Topological Insulators

Edge-State Physics Without Magnetic Fields in Science.

Solids can be divided into conductors and insulators. A new class of materials, called topological insulators, has been predicted (1, 2) that exhibit surface states that lead to quantized conductance of charge and spin. These surface states are helical edge states, which interconnect spin and momentum of the carriers. Observation of these states should not require application of a magnetic field.

Here's a potential application: Topological Quantum Image Analysis physics preprint.

A new approach to analyzing visual images is proposed, based on the idea of converting an optical image into a spatially varying pattern of polarized squeezed light, which is then used to produce a pattern of chiral edge currents in a thin film topological insulator. Thin films of Bi or Bi doped with Sb which are punctured with an array of sub-micron holes may be a way of realizing this kind of optical quantum information processing.

For a good introduction see A New Spin on the Insulating State in Science.

A Deeper Quantum Theory?

Is Quantum Theory Exact? by Stephen L. Adler and Angelo Bassi.
According to the standard theory, the state of a quantum system evolves deterministically according to Schrödinger's equation until the state is measured, when there's an apparently instantaneous nondeterministic transition to a new state.

How can we reconcile this probabilistic distribution of outcomes with the deterministic form of Schrödinger's equation? What precisely constitutes a "measurement?" At what point do superpositions break down, and definite outcomes appear? Is there a quantitative criterion, such as size of the measuring apparatus, governing the transition from coherent superpositions to definite outcomes? These puzzles have inspired a large literature in physics and philosophy.

The article asks whether there might be a deeper-level theory which explains quantum weirdness.
See also their preprint Collapse models with non-white noises.

Cats Modify Purring to Manipulate their Owners

Cat Purrs Evoke Baby Cries

There may be more to a cat's purr than meets the ear. A new study reports that our feline friends modify their signature sound when seeking food, adding a higher-frequency element that exploits our sensitivity to infant wails--and thus making it harder to ignore.

Elegant Microfluidic Images

This article contains more nice photomicrographs of emulsions High-Order Multiple Emulsions Formed in Poly(dimethylsiloxane) Microfluidics.

Climate Flip-Flops

What Drives Climate Flip-Flops?

Around 14,600 years ago, the atmospheric circulation over the North Atlantic region flipped within just a few years to another state (2); also, Greenland temperatures skyrocketed by >10°C over several decades (3), terminating a cold phase known as Heinrich Event 1. The global impacts of this Bølling-Allerød transition have been well documented with climate proxy records such as sediment cores and ice cores, but the physical conditions that triggered the transition remain controversial. The temperature evolution from the Heinrich Event 1 to the Bølling-Allerød and the subsequent Younger Dryas cold phase (see the figure) is strikingly similar to the Dansgaard-Oeschger cycles (4) that dominated Northern Hemispheric climate between 60,000 and 30,000 years ago (5). Hence, unraveling the processes that triggered the Bølling-Allerød transition may also help to elucidate the mysterious, tantalizingly regular Dansgaard-Oeschger cycles (6).

Giant Planets on the Move!

Shifting Orbits Gave Solar System A Big Shakeup, Model Suggests

Planetary scientists are finding that the four outermost planets of our solar system haven't always been orbiting where they are today. They've moved, some a considerable distance outward. The most catastrophic scenario for such planet migration, dubbed the Nice model (after the French city), has been gaining ground of late. It envisions the great reshuffling as a brief, violent affair that not only put the outer planets where they are today but also created the Kuiper belt of small icy bodies beyond Neptune, gave the planets scores of oddly orbiting moons, and bombarded the solar system with a rain of asteroids and comets so fierce that it would have cooked all but the deepest subterranean life on early Earth. The latest support for the Nice model, a new explanation for primitive-looking asteroids, appears this week in Nature. But the model has more hurdles to clear, such as explaining why the innermost planets—Earth and its neighbors—weren't reshuffled as well.

Mysterious Ancient Global Warming

Ancient Climate-Change Event Puzzles Scientists

Over the past couple of decades, researchers have been gathering data about a mysterious event known as the Paleocene-Eocene Thermal Maximum (PETM). The data, derived from drill cores brought up from the deep seabed in the Atlantic and Pacific Oceans, show that the surface temperature of the planet rose by as much as 9°C within 10,000 years during the PETM, which itself started out warmer than our current world. Temperatures stayed at this elevated level for nearly 100,000 years.

Steven Weinberg on Quantum Field Theory - Video

The Quantum Theory of Fields: Effective or Fundamental? talk by Steven Weinberg at CERN, July, 2009.

Statistics and Causality

FUNDAMENTALS OF STATISTICAL CAUSALITY

Traditionally, Statistics has been concerned with uncovering and describing associations, and statisticians have been wary of causal interpretations of their findings. But users of Statistics have rarely had such qualms. For otherwise what is it all for?
The enterprise of “Statistical Causality” has developed to take such concerns seriously. It has led to the introduction of a variety of formal methods for framing and understanding causal questions, and specific techniques for collecting and analysing data to shed light on these.

One of the examples mentioned is the quite simple but highly unintuitive Simpson's Paradox. The Berkeley sex bias case is particularly bizarre.

Feynman Videos Online at Microsoft

Videos of a series of lectures from 1964 by Physics Nobel Prize winner Richard Feynman has been placed on the web at Microsoft.
"This law has been called the greatest generalization achieved by the human mind. And you can get already from my introduction, that I'm interested not so much in the human mind as in the marvel of nature, who can obey such an elegant and simple law as this law of gravitation. So our main concentration will not be on how clever we are to have found it all out, but on how clever she is to pay attention to it."

Primordial Lithium Problem

A Bitter Pill: The Primordial Lithium Problem Worsens

The lithium problem arises from the significant discrepancy between the primordial 7Li abundance as predicted by BBN theory and the WMAP baryon density, and the pre-Galactic lithium abundance inferred from observations of metal-poor (Population II) stars. This problem has loomed for the past decade, with a persistent discrepancy of a factor of 2--3 in 7Li/H.

Effect of quark-mass variation on big bang nucleosynthesis

Measurements of the primordial baryon-to-photon ratio
η from the cosmic microwave background from
WMAP [1], coupled with precise measurements of the
neutron half-life [2], have made big bang nucleosynthesis
(BBN) an essentially parameter-free theory [2, 3, 4]. In
this paradigm excellent agreement has been obtained between
predicted and observed abundances of deuterium
and 4He (see, e.g. the Particle Data Group review [2] and
references therin). However there is some disagreement
for 7Li, the only other element for which the abundance
has been measured to an accuracy at which fruitful comparison
with theory can be made. While the “lithium
problem” has been known for some time, it has been exacerbated
by recent measurements of the 3He(α, γ)7Be
reaction [5]. Standard BBN theory with η provided
by WMAP 5 overproduces 7Li by a factor of 2.4 – 4.3
(around 4 – 5σ) [4].

Solar System Anomalies

There are at least four unexplained anomalies connected with astrometric data. Perhaps the most disturbing is the fact that when a spacecraft on a flyby trajectory approaches the Earth within 2000 km or less, it often experiences a change in total orbital energy per unit mass. Next, a secular change in the astronomical unit AU is definitely a concern. It is increasing by about 15 cm yr$^{-1}$. The other two anomalies are perhaps less disturbing because of known sources of nongravitational acceleration. The first is an apparent slowing of the two Pioneer spacecraft as they exit the solar system in opposite directions. Some astronomers and physicists are convinced this effect is of concern, but many others are convinced it is produced by a nearly identical thermal emission from both spacecraft, in a direction away from the Sun, thereby producing acceleration toward the Sun. The fourth anomaly is a measured increase in the eccentricity of the Moon's orbit. Here again, an increase is expected from tidal friction in both the Earth and Moon. However, there is a reported unexplained increase that is significant at the three-sigma level. It is prudent to suspect that all four anomalies have mundane explanations, or that one or more anomalies are a result of systematic error. Yet they might eventually be explained by new physics. For example, a slightly modified theory of gravitation is not ruled out, perhaps analogous to Einstein's 1916 explanation for the excess precession of Mercury's perihelion.

Space-Time Sensors using Atomic Levitation

Space-Time Sensors using Multiple-Wave Atomic Levitation

Optical atomic clocks are promising tools to investigate basics physics through fundamental tests. The best clocks to date control the atomic motion by trapping the sample in an optical lattice and then interrogate the atomic transition by shining on these atoms a distinct laser of controlled frequency. In order to perform both operations simultaneously and with the same laser field, we propose to use instead the levitation of a Bose-Einstein condensate through multiple-wave atomic interferences. The levitating condensate experiences a coherent localization in momentum and a controlled diffusion in altitude. The sample levitation is bound to a set of resonance conditions used either for frequency or for acceleration measurements. The chosen vertical geometry solves the limitations imposed by the sample free fall in previous optical clocks using also atomic interferences. This configuration allows for multiple-wave interference effects, which maintain the atomic population in levitation and yield a sensitivity improvement. This setup constitutes an attractive alternative to current atomic clocks and gravimeters.

Cosmic Microwave Background Anomalies

NASA / WMAP Science Team

Large scale alignment anomalies of CMB anisotropies: a new test for residuals applied to WMAP 5yr maps
The paper lists some anomalies of the CMB with respect to the lambda cold dark matter model:
1. There is low correlation (essentially zero) at large angles, not expected.
2. Unlikely alignments of low order multipole moments: the quadrupole and octupole moments with the dipole moment (which is caused by the motion of the earth). AKA "The Axis of Evil".
3. The two hemispheres defined by the plane of the solar system are asymmetric.
4. A Cold Spot in the southern hemisphere.

Dark Matter Astrophysics

Dark Matter Astrophysics preprint

These lectures are intended to provide a brief pedagogical review of dark matter for the newcomer to the subject. We begin with a discussion of the astrophysical evidence for dark matter. The standard weakly-interacting massive particle (WIMP) scenario--the motivation, particle models, and detection techniques--is then reviewed. We provide a brief sampling of some recent variations to the standard WIMP scenario as well as some alternatives (axions and sterile neutrinos). Exercises are provided for the reader.

Hominin Evolution

Middle and later Pleistocene hominins in Africa and Southwest Asia in PNAS.

Approximately 700,000 years ago, Homo erectus in Africa was giving way to populations with larger brains accompanied by structural adjustments to the vault, cranial base, and face. Such early Middle Pleistocene hominins were not anatomically modern. Their skulls display strong supraorbital tori above projecting faces, flattened frontals, and less parietal expansion than is the case for Homo sapiens. Postcranial remains seem also to have archaic features. Subsequently, some groups evolved advanced skeletal morphology, and by ca. 200,000 years ago, individuals more similar to recent humans are present in the African record. These fossils are associated with Middle Stone Age lithic assemblages and, in some cases, Acheulean tools. Crania from Herto in Ethiopia carry defleshing cutmarks and superficial scoring that may be indicative of mortuary practices. Despite these signs of behavioral innovation, neither the Herto hominins, nor others from Late Pleistocene sites such as Klasies River in southern Africa and Skhūl/Qafzeh in Israel, can be matched in living populations. Skulls are quite robust, and it is only after ≈35,000 years ago that people with more gracile, fully modern morphology make their appearance. Not surprisingly, many questions concerning this evolutionary history have been raised. Attention has centered on systematics of the mid-Pleistocene hominins, their paleobiology, and the timing of dispersals that spread H. sapiens out of Africa and across the Old World. In this report, I discuss structural changes characterizing the skulls from different time periods, possible regional differences in morphology, and the bearing of this evidence on recognizing distinct species.

An ancient human skull (pictured above) was found in Israel at Skhūl cave!?

Genetic Analysis of Copernicus?

It's impressive that they can now do so much with remains that are over 400 years old. Genetic identification of putative remains of the famous astronomer Nicolaus Copernicus at PNAS.

We report the results of mitochondrial and nuclear DNA analyses of skeletal remains exhumed in 2005 at Frombork Cathedral in Poland, that are thought to be those of Nicolaus Copernicus (1473–1543). The analyzed bone remains were found close to the altar Nicolaus Copernicus was responsible for during his tenure as priest. The mitochondrial DNA (mtDNA) profiles from 3 upper molars and the femurs were identical, suggesting that the remains originate from the same individual. Identical mtDNA profiles were also determined in 2 hairs discovered in a calendar now exhibited at Museum Gustavianum in Uppsala, Sweden. This calendar was the property of Nicolaus Copernicus for much of his life. These findings, together with anthropological data, support the identification of the human remains found in Frombork Cathedral as those of Nicolaus Copernicus. Up-to-now the particular mtDNA haplotype has been observed only 3 times in Germany and once in Denmark. Moreover, Y-chromosomal and autosomal short tandem repeat markers were analyzed in one of the tooth samples, that was much better preserved than other parts of the skeleton. Molecular sex determination revealed that the skeleton is from a male individual, and this result is consistent with morphological investigations. The minimal Y-chromosomal haplotype determined in the putative remains of Nicolaus Copernicus has been observed previously in many countries, including Austria, Germany, Poland, and the Czech Republic. Finally, an analysis of the SNP located in the HERC2 gene revealed the C/C genotype that is predominant in blue-eyed humans, suggesting that Copernicus may have had a light iris color.

See this blog post for more information about the HERC2 gene HERC2 & blue eye color & Danes

B Factories

Future prospects of B physics

In recent years, the CKM picture of flavor and CP violation has been confirmed, mainly due to B decay data. Yet, it is likely that there are small corrections to this picture. We expect to find new physics not much above the weak scale. This new physics could modify flavor changing processes compared to their SM expectations. Much larger B decay data sets, which are expected from LHCb and super-B-factories, will be used to search for these deviations with much improved sensitivity. The combination of low and high energy data will be particularly useful to probe the structure of new physics.

LHCb detector

Hierarchy problems

In particle physics, the Hierarchy problem is the question why the weak force is 10^32 times stronger than gravity. The Cosmological constant problem is that most quantum field theories predict a huge cosmological constant from the energy of the quantum vacuum . The value is off by 120 orders of magnitude, which is said to be the worst prediction in theorectical physics! In the preprint The Concept of a Cosmographical Vacuum we have:

The argument for a novel concept with a not unique, ``Cosmographical Vacuum'' state which generates fermion and weak boson masses is outlined in a brief and concise way.

The following preprint discusses the particle physics hierarchy problem and the problem of the very small but nonzero neutrino masses using the (speculative) possibility of extra dimensions:
Signatures of Singlet Neutrinos in Large Extra Dimensions at the LHC

It is a challenge to explain why neutrinos are so light compared to other leptons. Small neutrino masses can be explained if right-handed fermions propagate in large extra dimensions. Fermions propagating in the bulk would have implications on Higgs boson decays. If the Higgs boson is discovered at the Large Hadron Collider (LHC), a detailed analysis may reveal the presence of large extra dimensions. This paper reviews the status of large extra-dimensional models in the context of the current limits on Higgs boson masses and the fundamental Planck scale in extra dimensions.

Solar Circulation Paradox

Secrets of Magnetohydrodynamic Hell: The Solar Circulation Paradox and the Geodynamo

Differential rotation is widely supposed to be essential for the dynamo effects that sustain solar and planetary magnetic fields, but dynamo effects tend to oppose the flows that drive them, and it is uncertain what drives differential rotation. The relative sign of the differential rotation and meridional circulation is not consistent with simple convection modified by Coriolis forces. We investigate dynamo mechanisms consistent with the observed solar circulation, and discuss how reactive JxB forces would affect such flows. We formulate scaling rules that relate the magnetic field strength to mean rotation and convective heat transport.

On Time Reversal Mirrors

Narcissus by Caravaggio
A friend of mine complained that her boyfriend accused her of never passing a mirror without checking herself out, and that she spent half her life looking at her face in the mirror. Well if that were true and my friend had herself a Time Reversal Mirror, she would never get older! Sorry, that application is not actually discussed in this preprint, despite the promising title: On time reversal mirrors.

Time reversal (TR) is the process of recording the signal, time-reversing and re-propagating the signal. When the signal is from a localized source the time reversed field is expected to focus on the source. Time reversal of acoustic waves has led to applications in ultrasound and underwater acoustics including brain therapy, lithotripsy, nondestructive testing and telecommunications [17]. An even greater potential holds for the time reversal of electro-magnetic waves which is closely related to optical phase conjugation [28].

While it isn't quite the fountain of youth for the narcissists among us, there are exciting applications.

Dorian Gray used a different technology to remain youthful.

The Space Station

Space Station Is Near Completion, Maybe the End Plan to 'De-Orbit' in 2016 Is Criticized - article in the Washington Post. After $100 billion dollars the space station should be completed next year. Then we're going to burn it up over the ocean in 2016. Nice. Essentially no science has ever been done on the space station, though there's supposed to be an experiment brought up on the last shuttle flight in 2010. After that the space station can only be reached by the Russian Soyuz. What a waste. Someone in the article suggested that instead of destroying it we should give it to China!
Photo NASA

Vanity Fair on Finance and Politics

It Came from Wasilla

The August 2009 issue of Vanity Fair magazine had several interesting articles: It Came From Wasilla a hatchet job about Sarah Palin; The Man Who Crashed the World on the collapse of financial giant AIG by Michael Lewis; RICH HARVARD, POOR HARVARD "If Harvard is so smart, how come its record $36.9 billion endowment has collapsed" about the financial problems of my neighbor here in Cambridge; and a strangely sweet story about paparazzi Michael Jackson’s Last Close-Up. You'll have to buy the magazine to read the article about Harvard, the rest are on the web site.
The Harvard article (p.145) claims that the average full professor at Harvard makes $192,600 not including benefits. I'm surprised that's so high. I had been under the impression that the most prestiguous universities could actually get away with paying their faculty comparatively lower wages because professors were willing to give up salary to work at a big name institution.

Swoopo

Swoopo is The Crack Cocaine of Auction Sites.

Mantis Shrimps are Really, Really Cute

Photos of mantis shrimps found on the web, for the source and attribution, click on the photo.

An Ancient Explosion of Land Plants?

When Earth greened over: Explosion of animal life could have been triggered by blanket of vegetation.

A thick, green carpet of photosynthetic life, on the scale of that seen today, exploded across Earth 850 million years ago — much earlier than thought — a new study suggests.

Spontaneous Symmetry Breaking

FROM BCS TO THE LHC

Steven Weinberg reflects on spontaneous symmetry breaking, and the connection between condensed-matter physics and particle physics

Unanswered Questions in the Electroweak Theory

Unanswered Questions in the Electroweak Theory by Chris Quigg

For all its triumphs, the electroweak theory has many shortcomings. It does not make specific predictions for the masses of the quarks and leptons or for the mixing among different flavors. It leaves unexplained how the Higgs boson mass could remain below 1 TeV in the face of quantum corrections that tend to lift it toward the Planck scale or a unification scale. The Higgs field that must pervade all of space to hide the electroweak symmetry contributes a vacuum energy density far in excess of what is observed. And the electroweak theory responds inadequately to challenges raised by astronomical observations, including the dark-matter problem and the baryon asymmetry of the Universe. These shortcomings argue for physics beyond the standard model; some possibilities are recalled.

Kindle Definitions continued

I've been reading Ivanhoe on the Kindle. It was written in 1812 and the story was set long before that. There are many archaic terms used in the book, for example: kirtle, dingle and baldric. I probably wouldn't have bothered looking those up if I was reading the book in print but it was nice and easy on the Kindle. Not that these are likely to come up in conversation, even here in Cambridge.

Classical vs. Quantum Thought?

Classical Logical versus Quantum Conceptual Thought: Examples in Economy, Decision theory and Concept Theory

Inspired by a quantum mechanical formalism to model concepts and their disjunctions and conjunctions, we put forward in this paper a specific hypothesis. Namely that within human thought two superposed layers can be distinguished: (i) a layer guided by an underlying classical deterministic process, giving rise to essentially logical thought and its indeterministic version modeled by classical probability theory; (ii) a layer guided by conceptual weights of different types, such as 'typicality', 'membership', 'representativeness', 'similarity', 'applicability', 'preference' or 'utility', giving rise to what we call 'conceptual thought', indeterministic in essence, but equally well, although very differently, organized than logical thought. A substantial part of the conceptual thought process can be modeled by quantum mechanical probabilistic structures. We consider examples of three specific domains of research where the effects of the presence of conceptual thought and its deviations from classical logical thought have been noticed and studied, i.e. economics, decision theory, and concept theories and which provide experimental evidence for our hypothesis.

A Brief History of Planet Earth

The Earth – For Physicists is an article by John Baez with a somewhat unfortunate title. You don't actually need a background in physics to follow this synopsis of the origin and development of our planet.

Definitions in Kindle

Though the Kindle user interface is admittedly rather rudimentary, there's one seemingly minor feature that works great in practice. While reading a document, when you move the cursor onto a word it gives you a one line definition at the bottom of the screen. Hit return and it switches to a screen with the complete definition. I use this feature quite frequently. Even when I'm more or less familiar with a word, it's sometimes nice to check the exact definition. I don't check definitions nearly enough when I read normally, due to laziness, but the Kindle makes it painless enough that I've been actually doing it.

Kindle Shines in the Sun

I recently purchased a Kindle DX from Amazon, mainly hoping to use it while travelling. I've more or less ignored it since the first couple of days after it arrived. But today is a gorgeous sunny day for a change here in Boston, so I decided to try to read something out on my deck, which is blazingly bright today. I brought out the Kindle and was pleasantly surprised by how easy it was to read while wearing a pair of extremely dark polarized sunglasses. I found reading on the Kindle easier on my eyes than a paperback book, perhaps in part because the print is somewhat larger on the Kindle. As a joke, I brought out my laptop. I could barely see anything on the laptop screen in the sunlight without my sunglasses and absolutely nothing with the sunglasses on.
On a nice sunny day I often would like to read outdoors, but usually find the eye strain too much. The Kindle seems to help in this situation.

On the other hand the E Ink display used by the Kindle has its quirks too: there's a dramatic flash when the page is changed and there's long decay time when erasing the cursor, etc. However, I don't really even notice the page change flash anymore, though I certainly did when I first got it.

This Snake is a Fake Out Artist

The Tentacled Snake, an aquatic reptile of southeast Asia, does a nice job of faking out its fish prey: Tentacled snakes turn C-starts to their advantage and predict future prey behavior.

Many People Reject Unfair Offers Even When They Screw Only Themselves

The private rejection of unfair offers and emotional commitment

In a series of experiments, we demonstrate that certain players of an economic game reject unfair offers even when this behavior increases rather than decreases inequity. A substantial proportion (30–40%, compared with 60–70% in the standard ultimatum game) of those who responded rejected unfair offers even when rejection reduced only their own earnings to 0, while not affecting the earnings of the person who proposed the unfair split (in an impunity game). Furthermore, even when the responders were not able to communicate their anger to the proposers by rejecting unfair offers in a private impunity game, a similar rate of rejection was observed. The rejection of unfair offers that increases inequity cannot be explained by the social preference for inequity aversion or reciprocity; however, it does provide support for the model of emotion as a commitment device. In this view, emotions such as anger or moral disgust lead people to disregard the immediate consequences of their behavior, committing them to behave consistently to preserve integrity and maintain a reputation over time as someone who is reliably committed to this behavior.

Giant Kangaroo was probably wiped out by Humans

The largest-ever kangaroo, Procoptodon goliah disappeared about the time that humans arrived in Australia. It appears that was not a coincidence: Extinction implications of a chenopod browse diet for a giant Pleistocene kangaroo.

A Tight Biological Loop

Prochlorococcus, a tiny photosynthesing marine bacteria, is one of the smallest and most abundant forms of life. It needs nitrogen which is often a limiting factor in its growth. Apparently a major source of its nitrogen is nitrate, which is produced by organsims which mainly feed on Prochlorococcus itself: Prochlorococcus: Approved for export!

The Economics of Piracy

Aaaargh-onomics a blog post in the New York Times by Edward L. Glaeser of Harvard, reviews Peter Leeson’s book “The Invisible Hook: The Hidden Economics of Pirates.”

Mr. Leeson’s book represents a serious attempt to use the tools of economics to make sense of the institutions of piracy. The book is another example of economic imperialism, the use of economics to make sense of real world phenomena that are outside the standard realm of economic science. It addresses an important force that did, and does, impact world trade. But as the skull and crossbones on its spine suggests, the book is also just fun.

Benford, Zipf and Pareto

In this blog post Benford’s law, Zipf’s law, and the Pareto distribution Fields medalist Terence Tao discusses three remarkable real-world statistical patterns: Benford’s law, Zipf’s law, and the Pareto distribution.

Isn't it Ironic?

How to Think, Say, or Do Precisely the Worst Thing for Any Occasion

In slapstick comedy, the worst thing that could happen usually does: The person with a sore toe manages to stub it, sometimes twice. Such errors also arise in daily life, and research traces the tendency to do precisely the worst thing to ironic processes of mental control. These monitoring processes keep us watchful for errors of thought, speech, and action and enable us to avoid the worst thing in most situations, but they also increase the likelihood of such errors when we attempt to exert control under mental load (stress, time pressure, or distraction). Ironic errors in attention and memory occur with identifiable brain activity and prompt recurrent unwanted thoughts; attraction to forbidden desires; expression of objectionable social prejudices; production of movement errors; and rebounds of negative experiences such as anxiety, pain, and depression. Such ironies can be overcome when effective control strategies are deployed and mental load is minimized.

Hurricane Prediction

There appears to be a connection between Central Pacific Warming events and the severity and pattern of hurricanes in the North Atlantic. Central Pacific Warming events occur around the international dateline and are apparently distinct from Eastern Pacific Warming events - El Nino: Impact of Shifting Patterns of Pacific Ocean Warming on North Atlantic Tropical Cyclones and Predicting El Niño's Impacts.

The Russians are going to Phobos

Phobos, one of the moons of Mars, is a strange object. The Russians are launching a sample return mission this year: Russia's Dark Horse Plan to Get to Mars.

Valentini's Critique of Quantum Theory

Is Quantum Mechanics Tried, True, Wildly Successful, and Wrong?

A skeptical physicist charges that his field has been wandering in a philosophical wilderness for 80 years. The good news: He thinks he knows the way out.

Many of Antony Valentini's other papers can also be found at arXiv by clicking on the author's name in this link: Quantum Theory at the Crossroads: Reconsidering the 1927 Solvay Conference

We reconsider the crucial 1927 Solvay conference in the context of current research in the foundations of quantum theory. Contrary to folklore, the interpretation question was not settled at this conference and no consensus was reached; instead, a range of sharply conflicting views were presented and extensively discussed. Today, there is no longer an established or dominant interpretation of quantum theory, so it is important to re-evaluate the historical sources and keep the interpretation debate open. In this spirit, we provide a complete English translation of the original proceedings (lectures and discussions), and give background essays on the three main interpretations presented: de Broglie's pilot-wave theory, Born and Heisenberg's quantum mechanics, and Schroedinger's wave mechanics. We provide an extensive analysis of the lectures and discussions that took place, in the light of current debates about the meaning of quantum theory. The proceedings contain much unexpected material, including extensive discussions of de Broglie's pilot-wave theory (which de Broglie presented for a many-body system), and a "quantum mechanics" apparently lacking in wave function collapse or fundamental time evolution. We hope that the book will contribute to the ongoing revival of research in quantum foundations, as well as stimulate a reconsideration of the historical development of quantum physics. A more detailed description of the book may be found in the Preface. (Copyright by Cambridge University Press (ISBN: 9780521814218), expected publication date 2007.)

Cosmic Reionization

Computer Simulations of Cosmic Reionization

The cosmic reionization of hydrogen was the last major phase transition in the evolution of the universe, which drastically changed the ionization and thermal conditions in the cosmic gas. To the best of our knowledge today, this process was driven by the ultra-violet radiation from young, star-forming galaxies and from first quasars. We review the current observational constraints on cosmic reionization, as well as the dominant physical effects that control the ionization of intergalactic gas. We then focus on numerical modeling of this process with computer simulations. Over the past decade, significant progress has been made in solving the radiative transfer of ionizing photons from many sources through the highly inhomogeneous distribution of cosmic gas in the expanding universe. With modern simulations, we have finally converged on a general picture for the reionization process, but many unsolved problems still remain in this young and exciting field of numerical cosmology.

Graphene

Graphene: Status and Prospects

Graphene is a wonder material with many superlatives to its name. It is the thinnest material in the universe and the strongest ever measured. Its charge carriers exhibit giant intrinsic mobility, have the smallest effective mass (it is zero) and can travel micrometer-long distances without scattering at room temperature. Graphene can sustain current densities 6 orders higher than copper, shows record thermal conductivity and stiffness, is impermeable to gases and reconciles such conflicting qualities as brittleness and ductility. Electron transport in graphene is described by a Dirac-like equation, which allows the investigation of relativistic quantum phenomena in a bench-top experiment. What are other surprises that graphene keeps in store for us? This review analyses recent trends in graphene research and applications, and attempts to identify future directions in which the field is likely to develop.

The Evolution of Sex

On the Origin of Sexual Reproduction

Sexual reproduction is costly, so what are the benefits? One of the hypotheses has a catchy name: the Red Queen theory - from the Lewis Carroll character who tells Alice she must keep running faster just to stay in the same place. In biology it's the theory that organisms have to keep changing to keep ahead of their parasites. The recombination of characteristics in sexual reproduction may help.
The widespread system of sexual reproduction found in humans and many other eukaryotes alternates haploid and diploid stages. In humans the gametes (egg and sperm) are hapolid, they only have one copy of each chromosome, while embryos and adult forms are diploid, they have two copies of each chromosome. There's an elaborate mechanism, meiosis, which converts the diploid form into the haploid form. There's another mechanism, ferilizaton, which goes from two haploid forms (the egg and sperm) to the diploid form.

The Evolution of Meiosis From Mitosis

... if there is one event in the whole evolutionary sequence at which my own mind lets my awe still overcome my instinct to analyse, and where I might concede that there may be a difficulty in seeing a Darwinian gradualism hold sway throughout almost all, it is this event—the initiation of meiosis. W. J. HAMILTON (999, p. 419)

THE origins of meiosis in early eukaryotic history have never been satisfactorily explained. Since the reduction-division process in meiosis is essential for sexual life cycles, discussion of the origins of meiosis has been closely tied to debates about the evolutionary value of sex itself and the selective pressures for its maintenance. Yet the cytological events involved in the origins of meiosis are as puzzling as the question of selective pressures. While meiosis almost certainly evolved from mitosis, it has not one but four novel steps: the pairing of homologous chromosomes, the occurrence of extensive recombination between non-sister chromatids during pairing, the suppression of sister-chromatid separation during the first meiotic division, and the absence of chromosome replication during the second meiotic division. This complexity presents a challenge to any Darwinian explanation of meiotic origins. While the simultaneous creation of these new features in one step seems impossible, their step-by-step acquisition via selection of separate mutations seems highly problematic, given that the entire sequence is required for reliable production of haploid chromosome sets. Both Maynard Smith (1978) and Hamilton (1999) regarded the origins of meiosis as one of the most difficult evolutionary problems.

This article discusses something which always bothered me. In meiosis, the chromosomes are replicated first, resulting in four copies of each homolog chromosome. But each gamete requires only one copy. Why not seperate into two gametes directly, without the initial replication - it seems simpler. Apparently, since meiosis evolved from mitosis, and the initial replication is very similiar to what happens in mitosis, it is a relatively simple evolutionary change.

Thus, and perhaps counterintuitively, the evolution of two-step meiosis requires fewer new events than the seemingly simpler one-step process

This article proposes that the main benefit of meiosis is prevention of damage during recombination. Recombination itself is helpful for repairing damaged chromosomes.

Wavefunction Uncollapse

Uncollapsing the wavefunction by undoing quantum measurements

We review and expand on recent advances in theory and experiments concerning the problem of wavefunction uncollapse: Given an unknown state that has been disturbed by a generalized measurement, restore the state to its initial configuration. We describe how this is probabilistically possible with a subsequent measurement that involves erasing the information extracted about the state in the first measurement.

Fool's Gold

Fool's Gold: How the Bold Dream of a Small Tribe at J.P. Morgan Was Corrupted by Wall Street Greed and Unleashed a Catastrophe. Author Gillian Tett follows the staff of J.P. Morgan as they developed new financial instruments (various kinds of derivatives) to better manage risk - and which ended up being used in very risky ways that significantly contributed to the current financial meltdown.

Carlos Castenada

Carlos Castenada was a UCLA anthropology student who wrote a popular series of books in the 1970's about his research into the practices of native Mexican "sorcerers" which included the consumption of psychoactive plants. As it turns out, he also had a cult, based in Los Angeles, largely of women devotees, some of whom were supposed to be witches. When Castenada died of cancer in the late nineties, five of the women disappeared without a trace - it is assumed they committed suicide. A skeleton found in Death Valley was identified as one of the "witches" in 2006. See The dark legacy of Carlos Castaneda in Salon and The Sorcerer's Apprentice: My Life with Carlos Castaneda by Amy Irving.

Isotope Separation

SWU for U and Me by Jeremy Bernstein. Urananium isotope seperation has been in the news of late because of Iran's efforts in this arena. This paper explains some of the theory behind gas centrifuges and some of the fascinating history as well. If equations aren't your cup of tea, try skipping past those sections to the ancedotes.

The Evolution of Cell membranes

Cell membranes are largely composed of phospholipids. Phospholipids in turn are built on a glycerol phosphate. The are two different glycerol phosphates in use, glycerol-1-phosphate (G1P) and glycerol-3-phosphate (G3P). The archaea use G1P and the eubacteria and the eukaryotes use G3P. The two phospholipids are synthesized in entirely different ways. The mystery is, how did two such different systems evolve, and what was the nature of the common ancestor? Compounding the mystery, eukaryote transciption and translation is similiar to the archea, while eukaryote cell membranes are similar to bacteria. See Ancestral lipid biosynthesis and early membrane evolution and archea cell membranes.

Julian Schnabel

The Nerve and the Will is a beautiful review of the work of Julian Schnabel, in the New York Review of Books.

Machiavellian Monkeys

Never Trust a Hungry Monkey
Monkeys give false alarms and then take food when the other monkeys run off.

Mechanical Entanglement

Quantum mechanics: Entanglement goes mechanical

A neat experiment shows that the mechanical vibration of two ion pairs separated by a few hundred micrometres is entangled — their motions are intrinsically and inseparably connected in a quantum way.

Entangled mechanical oscillators

Hallmarks of quantum mechanics include superposition and entanglement. In the context of large complex systems, these features should lead to situations as envisaged in the 'Schrödinger's cat'1 thought experiment (where the cat exists in a superposition of alive and dead states entangled with a radioactive nucleus). Such situations are not observed in nature. This may be simply due to our inability to sufficiently isolate the system of interest from the surrounding environment2, 3—a technical limitation. Another possibility is some as-yet-undiscovered mechanism that prevents the formation of macroscopic entangled states4. Such a limitation might depend on the number of elementary constituents in the system5 or on the types of degrees of freedom that are entangled. Tests of the latter possibility have been made with photons, atoms and condensed matter devices6, 7. One system ubiquitous to nature where entanglement has not been previously demonstrated consists of distinct mechanical oscillators. Here we demonstrate deterministic entanglement of separated mechanical oscillators, consisting of the vibrational states of two pairs of atomic ions held in different locations. We also demonstrate entanglement of the internal states of an atomic ion with a distant mechanical oscillator. These results show quantum entanglement in a degree of freedom that pervades the classical world. Such experiments may lead to the generation of entangled states of larger-scale mechanical oscillators8, 9, 10, and offer possibilities for testing non-locality with mesoscopic systems11. In addition, the control developed here is an important ingredient for scaling-up quantum information processing with trapped atomic ions

Giant Neutrinos from the Big Bang

Quantum physics: Attack of the giant neutrinos
Quantum Coherence of Relic Neutrinos

What is the entropy of the universe?

What is the entropy of the universe?

Standard calculations suggest that the entropy of our universe is dominated by black holes, whose entropy is of order their area in Planck units, although they comprise only a tiny fraction of its total energy. Statistical entropy is the logarithm of the number of microstates consistent with the observed macroscopic properties of a system, hence a measure of uncertainty about its precise state. Therefore, assuming unitarity in black hole evaporation, the standard results suggest that the largest uncertainty in the future quantum state of the universe is due to the Hawking radiation from evaporating black holes. However, the entropy of the matter precursors to astrophysical black holes is enormously less than that given by area entropy. If unitarity relates the future radiation states to the black hole precursor states, then the standard results are highly misleading, at least for an observer that can differentiate the individual states of the Hawking radiation.

The Mass Gap

In THE PROBLEM OF GAUGE THEORY Edward Witten discusses the mass gap in quantum field theory, one of the Clay Institute Millenium Prize problems.

The White Tiger

While on a scuba diving trip to Cocos Island last week, I read The White Tiger the 2008 Man Booker award winner, a coming-of-age story about a poor young man in India.

Self Control Studies in the New Yorker

Don’t! The secret of self-control

William Blake - Auguries of Innocence

William Blake - Auguries of Innocence

To see a world in a grain of sand,
And a heaven in a wild flower,
Hold infinity in the palm of your hand,
And eternity in an hour.

...

Joy and woe are woven fine,
A clothing for the soul divine.
Under every grief and pine
Runs a joy with silken twine.

Lepton Oscillations

Do charged leptons oscillate?

The question of whether charged leptons oscillate is discussed in detail, with a special emphasis on the coherence properties of the charged lepton states created via weak interactions. This analysis allows one to clarify also an important issue of the theory of neutrino oscillations.

The Fall of the Roman Empire

I just finished reading How Rome Fell by Adrian Goldsworthy. I found the story of the last "pagan" emperor Julian the Apostate most fascinating.

The Cartwheel Galaxy

The Cartwheel Galaxy may be the result of a collision with one of the two nearby galaxies to its right.
Hubble Space Telescope - NASA

Sahara Dust and Atlantic Ocean Temperatures

The Role of Aerosols in the Evolution of Tropical North Atlantic Ocean Temperature Anomalies

Observations and models show that northern tropical Atlantic surface temperatures are sensitive to regional changes in stratospheric volcanic and tropospheric mineral aerosols. However, it is unknown whether the temporal variability of these aerosols is a key factor in the evolution of ocean temperature anomalies. We used a simple physical model, incorporating 26 years of satellite data, to estimate the temperature response of the ocean mixed layer to changes in aerosol loadings. Our results suggest that the mixed layer’s response to regional variability in aerosols accounts for 69% of the recent upward trend, and 67% of the detrended and 5-year low pass–filtered variance, in northern tropical Atlantic Ocean temperatures.

Free Will

The Sources of Human Volition

Every day we make actions that seem to depend on our "free will" rather than on any obvious external stimulus. This capacity not only differentiates humans from other animals, but also gives us the clear sense of controlling our bodies and lives. It therefore forms a key element of our personal identity. However, such voluntary actions are a puzzle for modern neuroscience. Where do they come from? A study by Desmurget et al. (1) on page 811 of this issue reveals how the brain may produce our experience of initiating voluntary action.

Edgar Allan Poe - Cosmologist

If the universe is infinite and homogeneous why is the night sky dark? There's an argument that really the entire sky should be just as bright as the sun. That's called Olbers' paradox. Edgar Allan Poe was athe first to suggest a solution to this problem - that perhaps the universe had a beginning in time.

Face Recognition

Symmetry, probability, and recognition in face space

e essential midline symmetry of human faces is shown to play a key role in facial coding and recognition. This also has deep and important connections with recent explorations of the organization of primate cortex, as well as human psychophysical experiments. Evidence is presented that the dimension of face recognition space for human faces is dramatically lower than previous estimates. One result of the present development is the construction of a probability distribution in face space that produces an interesting and realistic range of (synthetic) faces. Another is a recognition algorithm that by reasonable criteria is nearly 100% accurate.

Green Fluorescent Protein

Green glow deciphered - Mysterious jellyfish gene widely used in biology find its place in nature.

Space Clocks

Title: Orbit determination for next generation space clocks

Over the last decade of the 20th century and the first few years of the 21st, the uncertainty of atomic clocks has decreased by about two orders of magnitude, passing from the low 10^-14 to below 10^-16, in relative frequency . Space applications in fundamental physics, geodesy, time/frequency metrology, navigation etc... are among the most promising for this new generation of clocks. Onboard terrestrial or solar system satellites, their exceptional frequency stability and accuracy makes them a prime tool to test the fundamental laws of nature, and to study gravitational potentials and their evolution.
In this paper, we study in more detail the requirements on orbitography compatible with operation of next generation space clocks at the required uncertainty based on a completely relativistic model. Using the ACES (Atomic Clock Ensemble in Space) mission as an example, we show that the required accuracy goal can be reached with relatively modest constraints on the orbitography of the space clock, much less stringent than expected from "naive" estimates. Our results are generic to all space clocks and represent a significant step towards the generalised use of next generation space clocks in fundamental physics, geodesy, and time/frequency metrology

Time

Time as an Illusion

We review the idea, due to Einstein, Eddington, Hoyle and Ballard, that time is a subjective label, whose primary purpose is to order events, perhaps in a higher-dimensional universe. In this approach, all moments in time exist simultaneously, but they are ordered to create the illusion of an unfolding experience by some physical mechanism. This, in the language of relativity, may be connected to a hypersurface in a world that extends beyond spacetime. Death in such a scenario may be merely a phase change.

Cenotes

I've just done a couple of dives at cenotes (sinkholes) in the Yucatan peninsula of Mexico. My favorite so far is Dos Ojos - extremely clear water, beautiful light, nice cave formations.

Carbon Tubes and Ribbons

Carbon nanoelectronics: unzipping tubes into graphene ribbons

We report on the transport properties of novel carbon nanostructures made of partially unzipped carbon nanotubes, which can be regarded as a seamless junction of a tube and a nanoribbon. We find that graphene nanoribbons act at certain energy ranges as a perfect valley filters for carbon nanotubes, with the maximum possible conductance. Our results show that a partially unzipped carbon nanotube is a magnetoresistive device, with a very large value of the magnetoresistance. We explore the properties of several structures combining nanotubes and graphene nanoribbons, demonstrating that they behave as optimal contacts for each other, and opening a new route for the design of mixed graphene/nanotube devices.

an extraordinary flare in the M87 jet

Hubble Space Telescope observations of an extraordinary flare in the M87 jet

HST-1, a knot along the M87 jet located 0.85 arcsec from the nucleus of the galaxy has experienced dramatic and unexpected flaring activity since early 2000. We present analysis of Hubble Space Telescope Near-Ultraviolet (NUV) imaging of the M87 jet from 1999 May to 2006 December that reveals that the NUV intensity of HST-1 has increased 90 times over its quiescent level and outshines the core of the galaxy. The NUV light curve that we derive is synchronous with the light curves derived in other wavebands. The correlation of X-ray and NUV light curves during the HST-1 flare confirms the synchrotron origin of the X-ray emission in the M87 jet. The outburst observed in HST-1 is at odds with the common definition of AGN variability usually linked to blazars and originating in close proximity of the central black hole. In fact, the M87 jet is not aligned with our line of sight and HST-1 is located at one million Schwarzchild radii from the super-massive black hole in the core of the galaxy.

Manta Rays

I've just returned from a wonderful experience with the Manta rays of San Benedicto Island, in the Pacific off the coast of Mexico. Thanks to Gregory Colbert, his film crew and friends, and the crew of the Nautilus Explorer for an amazing trip.

Thermodynanics from Quantum Mechanics

Origin of the Canonical Ensemble: Thermalization with Decoherence

It is shown that a system embedded in a closed quantum mechanical system relaxes to its canonical ensemble equilibrium state if the environment drives this system to a fully decoherent state and the excess energy can release from the system to the environment or backward. Our findings show that the canonical ensemble is a special state that may result from pure quantum dynamics, suggesting that quantum mechanics may be regarded as the foundation of quantum statistical mechanics

Statistical mechanics is one of cornerstones of modern physics but its foundations and basic postulates are still under debate [1, 2, 3, 4]. There is a common believe that a generic “system” that interacts with a generic environment evolves into a state described by the canonical ensemble. Experience shows that this is true but a detailed understanding of this process, which is crucial for a rigorous justification of statistical physics and thermodynamics, is still lacking.

Classical to quantum transition

Classical to quantum transition of a driven nonlinear nanomechanical resonator

Much experimental effort is invested these days in fabricating nanoelectromechanical systems (NEMS) that are sufficiently small, cold, and clean, so as to approach quantum mechanical behavior as their typical quantum energy scale $\hbar\Omega$ becomes comparable to that of the ambient thermal energy $k_{B}T$. Such systems will hopefully enable one to observe the quantum behavior of human-made objects, and test some of the basic principles of quantum mechanics. Here we expand and elaborate on our recent suggestion [PRL 99 (2007) 040404] to exploit the nonlinear nature of a nanoresonator in order to observe its transition into the quantum regime. We study this transition for an isolated resonator, as well as one that is coupled to a heat bath at either zero or finite temperature. We argue that by exploiting nonlinearities, quantum dynamics can be probed using technology that is almost within reach. Numerical solutions of the equations of motion display the first quantum corrections to classical dynamics that appear as the classical-to-quantum transition occurs. This provides practical signatures to look for in future experiments with NEMS resonators.

An empirical Gravity law up to galactic scales

An empirical Gravity law up to galactic scales

Modelling on the MOND proposal, we introduce an empirically motivated gravity law for galactic and sub-galactic scales. This, circumvents the need for the cumbersome and ill-defined transition regime which exists in MOND, when passing from the standard gravitational regime at high accelerations to the MOND regime at low accelerations. We show that the proposed force law does not violate dynamical constraints at sub-galactic and solar system scales, does not degrade the good fit of the MOND proposal at large galactic scales, and in fact, slightly improves the accordance with observations at dSph scales. The proposed gravity law hence yields a good description of gravitational phenomena from terrestrial to large galactic scales, within a unique framework, without the need to invoke the presence of the still undetected and hypothetically dominant dark matter. Isothermal equilibrium density profiles then yield projected surface density profiles for the local dSph galaxies in very good agreement with observational determinations, for values of the relevant parameters as inferred from recent observations of these Galactic satellites. The observed scaling relations for these systems are also naturally accounted for within the proposed scheme.

The Origin of Labor Division

In Bert Hölldobler, E.O. Wilson: "The Superorganism: The Beauty, Elegance, and Strangeness of Insect Societies", p39.

... solitary bees behave like semisocial species when forced forced together experimentally. ... the coerced partners proceed variously to divide labor in foraging, tunneling and guarding. ... The division of labor appears to be the result of a preexisting behavioral groundplan in which solitary individuals tend to move from one job to another after the first is completed. In eusocial special, the algorithm is transferred to the avoidance of a job already being filled by another nestmate. It is evident that progressively providing bees and wasps are already "spring loaded" for a rapid shift to eusociality once ecological factors favor the change.

Flying Micro Robot

UW researchers develop world's first flying microrobot for microscale applications it flys using magnetic levitation.
Credit: University of Waterloo

Nothing to Be Frightened Of

The first chapter of Nothing to Be Frightened Of by Julian Barnes.
The exchange below is between Barnes and his brother, they are discussing their neice C. and her boyfriend R.

Instead, I asked, "But you approve of R.?"

"It's irrelevant," my brother replied, "whether or not I approve of R."

"No, it's not. C. might want you to approve of him."

"On the contrary, she might want me not to approve of him."

"But either way, it's not irrelevant to her whether or not you approve or disapprove."

He thought this over for a moment. "You're right," he said.

You can perhaps tell from these exchanges that he is the elder brother.

Mapa de Cuauhtinchan No. 2

A Lost World on the Map a review of
Cave, City, and Eagle's Nest: An Interpretive Journey Through the Mapa de Cuauhtinchan No. 2
edited by Davíd Carrasco and Scott Sessions
University of New Mexico Press, 479 pp., $65.00
The indigenous map is from the sixteenth century Valley of Puebla in Mexico.

Measuring measurement

Measuring measurement

Measurement connects the world of quantum phenomena to the world of classical events. It plays both a passive role, observing quantum systems, and an active one, preparing quantum states and controlling them. Surprisingly - in the light of the central status of measurement in quantum mechanics - there is no general recipe for designing a detector that measures a given observable. Compounding this, the characterization of existing detectors is typically based on partial calibrations or elaborate models. Thus, experimental specification (i.e. tomography) of a detector is of fundamental and practical importance. Here, we present the realization of quantum detector tomography: we identify the optimal positive-operator-valued measure describing the detector, with no ancillary assumptions. This result completes the triad, state, process, and detector tomography, required to fully specify an experiment. We characterize an avalanche photodiode and a photon number resolving detector capable of detecting up to eight photons. This creates a new set of tools for accurately detecting and preparing non-classical light.

The Strong CP Problem

CP Violation occurs in weak but not strong nuclear reactions. Why? In theory, there could be a nonzero CP violating angle theta, but experimentally it is zero. One way that shows up is the neutron electron dipole moment, which is also zero experimentally. One possible explanation is a new particle, the axion.

Coronal Heating Problem

The temperature at surface of the sun is about 5800K, but the temperature of solar corona is millions of degrees kelvin. Why is the corona so hot? We don't yet know.
a solar coronal loop
The corona is a source for solar storms, in particular coronal mass ejections. The most powerful such storm on record was the solar storm of 1859.
Currently the sun is unusually quiet: Deep Solar Minimum.

Garbage Land

Garbage Land by Elizabeth Royte recounts the author's attempt to track the destiny of her household garbage and sewage.

The Bear Stearns Meltdown

I'm also reading House of Cards: A Tale of Hubris and Wretched Excess on Wall Street, about the Bear Stearns meltdown.

"when involved in a trade, look around the room and determine who the chump is and if the chump is not clear to you, assume it is YOU."

"So as an example, if a salesman and trader are talking about how they did a trade with a customer and they think there's a significant business opportunity that came of that trade, at Bear Stearns they might say, 'I just ripped that fucker's head off. I'm going to make a lot of money on this trade. That's fucking crazy.' But at Goldman Sachs a salesman and a trader would talk about, 'That's a great opportunity. That was a very attractive and commercial price you purchased those securities at and I think we'll have a very interesting economic opportunity in the near future.'

Whales Battle on the Silver Bank

There was a spectactular battle between two humpback whales on the Silver Bank this year (2009) here are the photographs.

The Baseline Scenario

The Baseline Scenario is a blog about the current global financial crisis, written by Simon Johnson and James Kwak. Here a couple of their other recent articles.
The Radicalization of Ben Bernanke in the Washington Post.
He is throwing trillions of dollars at the financial crisis. What happens if his gambles don't pay off?
The Quiet Coup in the Atlantic.

The crash has laid bare many unpleasant truths about the United States. One of the most alarming, says a former chief economist of the International Monetary Fund, is that the finance industry has effectively captured our government—a state of affairs that more typically describes emerging markets, and is at the center of many emerging-market crises. If the IMF’s staff could speak freely about the U.S., it would tell us what it tells all countries in this situation: recovery will fail unless we break the financial oligarchy that is blocking essential reform. And if we are to prevent a true depression, we’re running out of time.

The Global Oceanic Conveyer Belt

There's a nice simplifed explanation of global thermohaline ocean circulation at Oceanic Conveyer Belt. The rest of the site nicely explains other aspects of "ocean motion".

Social Motives for Syntax

Social Motives for Syntax in Science.
Book review of Origins of Human Communication by Michael Tomasello,
MIT Press, Cambridge, MA, 2008. 407 pp. $36, £23.95. ISBN 9780262201773.

Summary: Tomasello argues for the importance of social interactions in an evolutionary transformation from pointing and pantomiming to human vocal communication.

On the Origin of Flowering Plants

On the Origin of Flowering Plants

Summary: Which plant was the mother of all angiosperms? In the fourth essay in Science's series in honor of the Year of Darwin, Elizabeth Pennisi discusses efforts to answer Darwin's question about how flowering plants diversified and spread so rapidly across the globe.

Sleeping to Reset Overstimulated Synapses

Sleeping to Reset Overstimulated Synapses in Science.

Summary: In this week's issue of Science (pp. 105 and 109), two studies with fruit flies provide what some researchers say is the most compelling evidence to date for the provocative hypothesis that sleep dials down synapses that have been cranked up by a day's worth of neural activity, helping to conserve both energy and precious real estate in the brain.

The North Atlantic Oscillation and Medieval Climate

Persistent Positive North Atlantic Oscillation Mode Dominated the Medieval Climate Anomaly in Science.

The Medieval Climate Anomaly (MCA) was the most recent pre-industrial era warm interval of European climate, yet its driving mechanisms remain uncertain. We present here a 947-year-long multidecadal North Atlantic Oscillation (NAO) reconstruction and find a persistent positive NAO during the MCA. Supplementary reconstructions based on climate model results and proxy data indicate a clear shift to weaker NAO conditions into the Little Ice Age (LIA). Globally distributed proxy data suggest that this NAO shift is one aspect of a global MCA-LIA climate transition that probably was coupled to prevailing La Niña–like conditions amplified by an intensified Atlantic meridional overturning circulation during the MCA.

Exploring the Quantum Vacuum with Lasers

Quantum Vacuum Experiments Using High Intensity Lasers

The quantum vacuum constitutes a fascinating medium of study, in particular since near-future laser facilities will be able to probe the nonlinear nature of this vacuum. There has been a large number of proposed tests of the low-energy, high intensity regime of quantum electrodynamics (QED) where the nonlinear aspects of the electromagnetic vacuum comes into play, and we will here give a short description of some of these. Such studies can shed light, not only on the validity of QED, but also on certain aspects of nonperturbative effects, and thus also give insights for quantum field theories in general.

A Solar Twin?

High-Dispersion Spectroscopic Study of Solar Twins: HIP 56948, HIP 79672, and HIP 100963

An intensive spectroscopic study was performed for three representative solar twins (HIP 56948, HIP 79672, and HIP 100963) as well as for the Sun (Moon; reference standard), with an intention of (1) quantitatively discussing the relative-to-Sun similarities based on the precisely established differential parameters and (2) investigating the reason causing the Li abundance differences despite their similarities. It was concluded that HIP 56948 most resembles the Sun in every respect including the Li abundance (though not perfectly similar) among the three and deserves the name of "closest-ever solar twin", while HIP 79672 and HIP 100963 have somewhat higher effective temperature and appreciably higher surface Li composition. While there is an indication of Li being rotation-dependent because the projected rotation in HIP 56948 (and the Sun) is slightly lower than the other two, the rotational difference alone does not seem to be so large as to efficiently produce the marked change in Li. Rather, this may be more likely to be attributed (at least partly) to the slight difference in T_eff via some T_eff-sensitive Li-controlling mechanism. Since the abundance of beryllium was found to be essentially solar for all stars irrespective of Li, any physical process causing the Li diversity should work only on Li without affecting Be.

See also Age and mass of solar twins constrained by lithium abundance

Neutron Stars

The Behavior of Matter under Extreme Conditions

The cores of neutron stars harbor the highest matter densities known to occur in nature, up to several times the densities in atomic nuclei. Similarly, magnetic field strengths can exceed the strongest fields generated in terrestrial laboratories by ten orders of magnitude. Hyperon-dominated matter, deconfined quark matter, superfluidity, even superconductivity are predicted in neutron stars. Similarly, quantum electrodynamics predicts that in strong magnetic fields the vacuum becomes birefringent. The properties of matter under such conditions is governed by Quantum Chromodynamics (QCD) and Quantum Electrodynamics (QED), and the close study of the properties of neutron stars offers the unique opportunity to test and explore the richness of QCD and QED in a regime that is utterly beyond the reach of terrestrial experiments. Experimentally, this is almost virgin territory.

Local Void vs Dark Energy

Local Void vs Dark Energy: Confrontation with WMAP and Type Ia Supernovae

It is now a known fact that if we happen to be living in the middle of a large underdense region, then we will observe an "apparent acceleration", even when any form of dark energy is absent. In this paper, we present a "Minimal Void" scenario, i.e. a "void" with minimal underdensity contrast (of about -0.4) and radius (~ 200-250 Mpc/h) that can, not only explain the supernovae data, but also be consistent with the 3-yr WMAP data. We also discuss consistency of our model with various other measurements such as Big Bang Nucleosynthesis, Baryon Acoustic Oscillations and local measurements of the Hubble parameter, and also point out possible observable signatures.

Antimatter Annihilation Anomalies

PAMELA and other experiments are searching for antimatter annihilation, as possible evidence for Dark Matter and other astrophysical phenomenon. These experiments have observed excess positron annihilation, but not antiprotons, which is inconsistent with many popular Dark Matter models. See also Dark Matter Annihilation and the PAMELA and ATIC Anomaly and Discriminate different scenarios to account for the PAMELA and ATIC data by synchrotron and IC radiation and Is the PAMELA anomaly caused by the supernova explosions near the Earth?
See also A hint of dark matter? in Nature.

Cosmic ray positrons are known to be produced in interactions in the interstellar medium. As well as originating from this 'secondary source', positrons might also be generated in primary sources such as pulsars and microquasars — or by dark matter annihilation. A new measurement of the positron fraction in the cosmic radiation for the energy range 1.5–100 GeV has been made using data from the PAMELA satellite experiment. Previous measurements, made predominantly by balloon-borne instruments, yield a positron fraction compatible with 'secondary source' production from interactions between cosmic ray nuclei and interstellar matter. Above 10 GeV the new measurements deviate significantly from this expectation, pointing to the presence of a primary source, either a nearby astrophysical object or dark matter particle annihilations.

The cosmic ray lepton puzzle in the light of cosmological N-body simulations

The PAMELA and ATIC collaborations have recently reported an excess in the cosmic ray positron and electron fluxes. These lepton anomalies might be related to cold dark matter (CDM) particles annihilating within a nearby dark matter clump. We outline regions of the parameter space for both the dark matter subhalo and particle model, where data from the different experiments are reproduced. We then confront this interpretation of the data with the results of the cosmological N-body simulation Via Lactea II. Having a sizable clump (Vmax = 9km/s) at a distance of only 1.2 kpc could explain the PAMELA excess, but such a configuration has a probability of only 0.37 percent. Reproducing also the ATIC bump would require a very large, nearby subhalo, which is extremely unlikely (p~3.10^-5). In either case, we predict Fermi will detect the gamma-ray emission from the subhalo. We conclude that under canonical assumptions, the cosmic ray lepton anomalies are unlikely to originate from a nearby CDM subhalo.

Radio Emissions from the Center of the Milky Way

Modeling Emission from the Supermassive Black Hole in the Galactic Center with GRMHD Simulations

Sagittarius A* is a compact radio source at the Galactic center, powered by accretion of fully ionized plasmas into a supermassive black hole. However, the radio emission cannot be produced through the thermal synchrotron process by a gravitationally bounded flow. General relativistic magneto-hydrodynamical(GRMHD) simulations of black hole accretion show that there are strong unbounded outflows along the accretion. With the flow structure around the black hole given by GRMHD simulations, we investigate whether thermal synchrotron emission from these outflows may account for the observed radio emission. We find that simulations producing relatively high values of plasma beta cannot produce the radio flux level without exceeding the X-ray upper limit set by Chandra observations through the bremsstrahlung process. The predicted radio spectrum is also harder than the observed spectrum both for the one temperature thermal model and a simple nonthermal model with a single power-law electron distribution. The electron temperature needs to be lower than the gas temperature near the black hole to reproduce the observed radio spectrum. A more complete modeling of the radiation processes, including the general relativistic effects and transfer of polarized radiation, will give more quantitative constraints on physical processes in Sgr A* with the current multi-wavelength, multi-epoch, and polarimetric observations of this source.