Tuesday, September 29, 2009

Fashion illustrator Kareem Iliya

Kareem Iliya, fashion illustrator, images can be found here and here.

Monday, September 28, 2009

The Hurt Locker

The Hurt Locker directed by Kathryn Bigelow is quite an intense film about an army bomb disposal unit in Iraq.

Juliette Binoche

French actress Juliette Binoche and English choreographer Akram Khan performed their dance/drama piece In-I at BAM. I saw the closing night peformance, which wound up with a spectacular finale.
She also recently published a book of her paintings "Juliette Binoche, Portraits In-Eyes". The book contains a series of side-by-side pairs of paintings inspired by each of her films. Each pair consists of a painting of the film's director and then a self portrait of herself "in character". Cool. The text is in both French and English.

William Blake at the Morgan Library

William Blake's World: "A New Heaven Is Begun" an exhibit at the Morgan Library in New York. At that link there's a nice reading of "The Tyger" and other poems by Jeremy Irons.
William's Blake's illustrations to the Book of Job can be found here. I was quite surprised by Blake's depiction of Satan: he's rather physically attractive and was not usually shown as particularly "evil looking".

Thursday, September 24, 2009

Massive Violation of Bell's Inequality

Violation of Bell's inequality in Josephson phase qubits in Nature.
The measurement process plays an awkward role in quantum mechanics, because measurement forces a system to 'choose' between possible outcomes in a fundamentally unpredictable manner. Therefore, hidden classical processes have been considered as possibly predetermining measurement outcomes while preserving their statistical distributions1. However, a quantitative measure that can distinguish classically determined correlations from stronger quantum correlations exists in the form of the Bell inequalities, measurements of which provide strong experimental evidence that quantum mechanics provides a complete description2, 3, 4. Here we demonstrate the violation of a Bell inequality in a solid-state system. We use a pair of Josephson phase qubits5, 6, 7 acting as spin-1/2 particles, and show that the qubits can be entangled8, 9 and measured so as to violate the Clauser–Horne–Shimony–Holt (CHSH) version of the Bell inequality10. We measure a Bell signal of 2.0732 0.0003, exceeding the maximum amplitude of 2 for a classical system by 244 standard deviations. In the experiment, we deterministically generate the entangled state, and measure both qubits in a single-shot manner, closing the detection loophole11. Because the Bell inequality was designed to test for non-classical behaviour without assuming the applicability of quantum mechanics to the system in question, this experiment provides further strong evidence that a macroscopic electrical circuit is really a quantum system7.

Genetic Structure of India

Indian ancestry revealed in Nature.
"The mixing of two distinct lineages led to most modern-day Indians."

Ultra-Cold Microscale Optomechanical Oscillator

Demonstration of an ultracold micro-optomechanical oscillator in a cryogenic cavity
Preparing and manipulating quantum states of mechanical resonators is a highly interdisciplinary undertaking that now receives enormous interest for its far-reaching potential in fundamental and applied science. Up to now, only nanoscale mechanical devices achieved operation close to the quantum regime. We report a new micro-optomechanical resonator that is laser cooled to a level of 30 thermal quanta. This is equivalent to the best nanomechanical devices, however, with a mass more than four orders of magnitude larger (43 ng versus 1 pg) and at more than two orders of magnitude higher environment temperature (5 K versus 30 mK). Despite the large laser-added cooling factor of 4,000 and the cryogenic environment, our cooling performance is not limited by residual absorption effects. These results pave the way for the preparation of 100-um scale objects in the quantum regime. Possible applications range from quantum-limited optomechanical sensing devices to macroscopic tests of quantum physics.

Observation of strong coupling between a micromechanical resonator and an optical cavity field
Achieving coherent quantum control over massive mechanical resonators is a current research goal. Nano- and micromechanical devices can be coupled to a variety of systems, for example to single electrons by electrostatic or magnetic coupling, and to photons by radiation pressure or optical dipole forces. So far, all such experiments have operated in a regime of weak coupling, in which reversible energy exchange between the mechanical device and its coupled partner is suppressed by fast decoherence of the individual systems to their local environments. Controlled quantum experiments are in principle not possible in such a regime, but instead require strong coupling. So far, this has been demonstrated only between microscopic quantum systems, such as atoms and photons (in the context of cavity quantum electrodynamics) or solid state qubits and photons. Strong coupling is an essential requirement for the preparation of mechanical quantum states, such as squeezed or entangled states, and also for using mechanical resonators in the context of quantum information processing, for example, as quantum transducers. Here we report the observation of optomechanical normal mode splitting, which provides unambiguous evidence for strong coupling of cavity photons to a mechanical resonator. This paves the way towards full quantum optical control of nano- and micromechanical devices.

Nature 460, 724-727 (2009)
DOI: 10.1038/nature08171

Wednesday, September 23, 2009

Cool Airship Video


The Lockheed P-791.

Gravity Insulators??


I noticed this stone a long time ago on the Tufts campus. A couple of older ladies with pronounced Irish accents read it and pronounced it "a lovely idea", haha.
I wondered at the time how such an outlandish monument ended up at a reputable university. Well Wikipedia Knows All: Gravity Research Foundation

Supersymmetry and Division Algebras

There's a surprising connection between supersymmetry , a hot topic in theoretical physics, and division algebras: the real, complex, quaternion and octonion number systems. Supersymmetry only works in 3,4,6 and 10 space time dimensions. That's because there's a cute little trick which allows us to represent an n+2 dimensional spacetime vector using one number from a division algebra and two additional real numbers. There are only four division algebras - which just happen to have 1,2,4 and 8 dimensions. John Baez Explains It All To You here.

Monday, September 21, 2009

Equal Temperament: Music Meets Mathematics

Generalized continued fractions and equal temperament
It would be nice if we could divide an octave into equal notes and then be able to have an interval close to a perfect fifth (which raises the frequency by 3/2). That's how equal temperament works: it divides an octave into twelve equal notes and then it turns out that an interval of seven notes is close to a perfect fifth. That's actually why this particular scale was chosen and a reason it has been so successful.

Antigravity

Antigravitation
We discuss why there are no negative gravitational sources in General Relativity and show that it is possible to extend the classical theory such that repulsive gravitational interaction occurs.

Interesting, but as the author points out in a previous preprint which provides more details of the theory: A Bi-Metric Theory with Exchange Symmetry "As this example shows, the bi-metric model is not causal ..."

Sunday, September 20, 2009

A Previous Yale Murder, Still Unsolved

Murder Most Yale a 1999 article in Vanity Fair about the murder of Suzanne Jovin a talented and beautiful Yale student - one of her professors was a suspect.

Fractal Cosmology

Fractal Cosmology is a theory of cosmology which models the universe as fractal: the universe is similar to itself at different scales.
Robert L. Oldershaw has published a series of papers in which he conjectures that certain types of stars are may be similiar to ... atoms of corresponding elements.
I would be very surprised if this turned out to be a fruitful approach, but it's a cool concept nonetheless.

Mandelbrot set: an example of a fractal - click for more info, more images

Inconstant Moon

Inconstant Moon is an episode of the Outer Limits American television show. It's based the short story (also titled Inconstant Moon) by Larry Niven. Many of Niven's stories have a basis in science fact, including this one.

Mike Murphy's reaction to the show was something like this "Absolute maximum horror: the world is ending so let's get married - then the world doesn’t end."

Friday, September 18, 2009

Optical Levitation

Cavity optomechanics using an optically levitated nanosphere
Recently, remarkable advances have been made in coupling a number of high-Q modes of nano-mechanical systems to high-finesse optical cavities, with the goal of reaching regimes where quantum behavior can be observed and leveraged toward new applications. To reach this regime, the coupling between these systems and their thermal environments must be minimized. Here we propose a novel approach to this problem, in which optically levitating a nano-mechanical system can greatly reduce its thermal contact, while simultaneously eliminating dissipation arising from clamping. Through the long coherence times allowed, this approach potentially opens the door to ground-state cooling and coherent manipulation of a single mesoscopic mechanical system or entanglement generation between spatially separate systems, even in room temperature environments. As an example, we show that these goals should be achievable when the mechanical mode consists of the center-of-mass motion of a levitated nanosphere.

Wednesday, September 16, 2009

Your Hippocampus Remembers More than You Do

Remembering Without Knowing It
In a memory task in which the subject was shown a photograph and then later asked to pick out that photo among several others, the subject's hippocampus activated when they were seeing the correct photo, even when they ended up choosing the wrong one!

Cosmology Review

Cosmology at a Crossroads
A fundamental question in cosmology is, "How did the universe begin?" The two pivotal ideas of inflation and cold dark matter (CDM), combined with extensive observational results, including the unpredicted accelerated expansion of the universe, underpin a new standard model of cosmology

Neanderthals were more Carnivorous than early modern Humans

Isotopic evidence for the diets of European Neanderthals and early modern humans
Neanderthals mainly fed on big-game, while early modern humans had a more varied diet, sometimes including lots of fish.

Genetics of the Human Expansion Out of Africa

Explaining worldwide patterns of human genetic variation using a coalescent-based serial founder model of migration outward from Africa
It seems that modern humans may have expanded out of Africa without mixing much with the descendants of earlier waves of migration.

Larvae and Adults are Hybrids??

Caterpillars evolved from onychophorans by hybridogenesis
I reject the Darwinian assumption that larvae and their adults evolved from a single common ancestor. Rather I posit that, in animals that metamorphose, the basic types of larvae originated as adults of different lineages, i.e., larvae were transferred when, through hybridization, their genomes were acquired by distantly related animals. “Caterpillars,” the name for eruciforms with thoracic and abdominal legs, are larvae of lepidopterans, hymenopterans, and mecopterans (scorpionflies). Grubs and maggots, including the larvae of beetles, bees, and flies, evolved from caterpillars by loss of legs. Caterpillar larval organs are dismantled and reconstructed in the pupal phase. Such indirect developmental patterns (metamorphoses) did not originate solely by accumulation of random mutations followed by natural selection; rather they are fully consistent with my concept of evolution by hybridogenesis. Members of the phylum Onychophora (velvet worms) are proposed as the evolutionary source of caterpillars and their grub or maggot descendants. I present a molecular biological research proposal to test my thesis. By my hypothesis 2 recognizable sets of genes are detectable in the genomes of all insects with caterpillar grub- or maggot-like larvae: (i) onychophoran genes that code for proteins determining larval morphology/physiology and (ii) sequentially expressed insect genes that code for adult proteins. The genomes of insects and other animals that, by contrast, entirely lack larvae comprise recognizable sets of genes from single animal common ancestors.

I would be surprised if this were true, but it's an interesting and novel hypothesis.

Sanction Threats reduce Reciprocity

Neural responses to sanction threats in two-party economic exchange
Sanctions are used ubiquitously to enforce obedience to social norms. However, recent field studies and laboratory experiments have demonstrated that cooperation is sometimes reduced when incentives meant to promote prosocial decisions are added to the environment. Although various explanations for this effect have been suggested, the neural foundations of the effect have not been fully explored. Using a modified trust game, we found that trustees reciprocate relatively less when facing sanction threats, and that the presence of sanctions significantly reduces trustee's brain activities involved in social reward valuation [in the ventromedial prefrontal cortex (VMPFC), lateral orbitofrontal cortex, and amygdala] while it simultaneously increases brain activities in the parietal cortex, which has been implicated in rational decision making. Moreover, we found that neural activity in a trustee's VMPFC area predicts her future level of cooperation under both sanction and no-sanction conditions, and that this predictive activity can be dynamically modulated by the presence of a sanction threat.

Jumping Robot

Video: Precision Urban Hopper leaps over fences, makes enemies cringe

Yow.

Tuesday, September 15, 2009

Palindromes on the Y Chromosome

New Clues to Sex Anomalies in How Y Chromosomes Are Copied
Most chromosomes come in pairs, which helps in detecting and repairing errors when DNA is copied. However, there's only one copy of the Y chromosome (found only in males) but many of its genes occur in palindromes (sequences which read the same forward and backward e.g. Madam Im Adam). When the Y chromosome is copied, the palindromic regions are folded over, so they can be compared for errors.

Sunday, September 13, 2009

The Simple Art of Murder

The Simple Art of Murder by Raymond Chandler (1950). An essay on the art and practice of the murder mystery.
See also The Simple Art of Murder a 1995 book review by Joyce Carol Oates about Raymond Chandler and an overview and critique of genre fiction.

Thursday, September 10, 2009

The Origin of Farming in Europe: Cultural Diffusion or Migration?

Ancient DNA Says Europe's First Farmers Came From Afar

Dogs and Infants make similiar errors, wolves don't

Like Infant, Like Dog
"The infants apparently believed believed adult instruction more than they believe their own eyes." Dogs behaved similarly.
Dogs: Kids in Fur Coats?

Erasing Fear Memories

Erasing Fear Memories
Memories of stressful events can be extinguished in young animals but are resistent to complete erasure in adults. New research hints at the neurobiological basis for these observations.

Photosystem genes in viruses

Photosystems at the double
Marine cyanobacteria viruses contain genes for both photosystems used in host photosynthesis.

Nano storage scheme which doesn't wear out

Nanotechnology: A gentle jackhammer
A futuristic method of data storage depends on the 'write–read' action of a multitude of tiny silicon tips. The concept of dynamic superlubricity offers a way to avoid the wear that would otherwise cripple them.

The History of Oxygen

Early Earth: Oxygen for heavy-metal fans
Chromium isotopes provide an eyebrow-raising history of oxygenation of Earth's atmosphere. Not least, it seems that oxygen might have all but disappeared half a billion years after its initial rise.

Sex Determination in Birds

Sex determination: Birds do it with a Z gene
The gene that determines sex in birds has eluded scientists for a decade. Now this all-important locus is revealed as a gene on the Z chromosome known for its proclivity for determining sex in all kinds of animals.

In mammals, males have XY chromosome pairs and females are XX, so the Y chromosome determines maleness and sex. In particular the SRY gene found on the Y chromosome determines testis.
In birds it's the other way around: males have ZZ chromosome pairs and females are ZW. However in birds the key gene is again for maleness and it resides on the Z chromosome.

Wednesday, September 02, 2009

Skateboard Park London




Sundial in Westminster London

Sundial at Saint Maragret's Church Westminster London. Also the correction curve to get civil time.

Arcadia by Tom Stoppard

Last night I saw Arcadia a play by Tom Stoppard in London. Ed Stoppard, the playwright's son, performs. The play discusses chaos theory, fractals, the second law of thermodyamics, romance versus rationality, poetry and academic rivalries - all in the format of a drawing room comedy.
I also saw the 1995 New York production directed by Trevor Nunn at Lincoln Center, which was absolutely brilliant.

The poet Lord Byron is a constant but never seen presence in the play which quotes the following lines from one of his poems:

She walks in beauty, like the night
Of cloudless climes and starry skies,
And all that's best of dark and bright
Meets in her aspect and her eyes;
Thus mellow'd to that tender light
Which Heaven to gaudy day denies