PRIMER PLANETA DISTANTE AZUL

First distant planet to be seen in colour is blue

Hubble Space Telescope measures visible light from an exoplanet.

 

  Blue gas giant.- By observing exoplanet HD 189733 b before, during and after it disappeared behind its host star, astronomers were able to discover that its colour is a deep blue. (Artist's impression.)

A navy-blue world orbiting a faraway star is the first exoplanet to have its colour directly measured. Discovered in 2005, HD 189733 b is one of the best-studied planets outside the Solar System, orbiting a star about 19 parsecs away in the Vulpecula, or Fox, constellation. Previous efforts to observe the planet focused on the infrared light it emits — invisible to the human eye.

Last December, astrophysicist Tom Evans at the University of Oxford, UK, and his colleagues used the Hubble Space Telescope to observe the planet and its host star. Hubble's optical resolution is not high enough to actually 'see' the planet as a dot of light separate from its star, so instead, the telescope receives light from both objects that mix into a single point source. To isolate the light contribution of the planet, Evans and his colleagues waited for the planet to move behind the star during its orbit, so that its light would be blocked, and looked for changes in light colour.

Nature News 11 July 2013

Study confirms principle’s limits on measurement accuracy.

 Werner Heisenberg’s concept of quantum uncertainty could now be on firmer ground.

INTERFOTO/Alamy

 Encapsulating the strangeness of quantum mechanics is a single mathematical expression. According to every undergraduate physics textbook, the uncertainty principle states that it is impossible to simultaneously know the exact position and momentum of a subatomic particle — the more precisely one knows the particle’s position at a given moment, the less precisely one can know the value of its momentum.

But the original version of the principle, put forward by physicist Werner Heisenberg in 1927, couches quantum indeterminism in a different way — as a fundamental limit to how well a detector can measure quantum properties. Heisenberg offered no direct proof for this version of his principle, and expressed his ideas “only informally and intuitively”, says physicist Jos Uffink of the University of Minnesota in Minneapolis.

Now researchers say that they have a formal proof. “Our work shows that you can’t measure something with an accuracy any better than the fundamental quantum uncertainty,” says Paul Busch, a theoretical physicist at the University of York, UK, who with his colleagues posted the proof on 6 June on the arXiv preprint server¹. Not only does the work place this measurement aspect of the uncertainty principle on solid ground — something that researchers had started to question — but it also suggests that quantum-encrypted messages can be transmitted securely.

Proof mooted for quantum uncertainty

 

FROG IN FLIGHT

Frog in flight — The photo was taken by Andres Andrade from the Center for Genomic Sciences, UNAM, Cuernavaca, Mexico, who works on how bacterial secondary metabolites can participate in the establishment of microbial communities.

RELOG CIRCADIANO LOCALIZADO EN LA ANTENA

Ecology

Getting It Just Right 

Sacha Vignieri  Volume 339, Number 6125, Issue of 15 March 2013

  

North American monarch butterflies are known for the massive southern migrations they undertake each year. During these migrations, a single butterfly may fly over 2500 miles south to the overwintering site, where it enters diapause, a hibernation-like state. This same butterfly will then fly northward in the spring, where it will become reproductive before dying and leaving the remainder of the return trip to its offspring. Monarchs coordinate their southward flight on the basis of a Sun compass mediated through circadian clocks located in the antennae. Guerra and Reppert now show that northbound flight is mediated by the same Sun compass mechanism. This finding begs the question, however, of how individuals are able to "switch" their compasses to fly south in the fall and north in the spring. Exposure of fall remigrants to variations of the day length and temperature conditions encountered at overwintering sites revealed that although day length has no effect on flight direction, temperature was able to facilitate the directional switch. Specifically, butterflies exposed to temperatures that were too warm did not switch their flight directions, whereas those exposed to appropriately cold temperatures flew north as expected. Thus, cold temperatures during overwintering are necessary for the completion of the enigmatic migration. Furthermore, warmer winters at these sites, due to climate change, may interfere with the monarch's migration home.

Curr. Biol. 10.1016/j.cub.2013.01.052 (2013).

The End of the Beginning for the Brain

• Books et al. Neurobiology

Replicant's end. Publicity still from Ridley Scott's Blade Runner (1982). CREDIT: LADD COMPANY/WARNER BROS./THE KOBAL COLLECTION

Science-fiction novels and films have long popularized the notion that machines will, sooner or later, match and ultimately exceed human-level intelligence. On the way they will acquire feelings and consciousness. In the most famous such movie, Blade Runner, a replicant exclaims in the face of its imminent demise,

"I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I watched c-beams glitter in the dark near the Tannhäuser Gate. All those moments will be lost in time, like tears in rain. Time to die."

—revealing in its eloquence and poignancy its (simulated) humanity. 

 Science 15 February 2013:
Vol. 339 no. 6121 pp. 759-76

ROBOTICS

Tiny, winged machines

Insect-sized robots can mimic the hovering and darting of flies.

Flies have long been admired for their aerial agility, but technical limitations in miniaturization have hindered attempts to replicate this in similar-sized robots. Kevin Ma and his colleagues at Harvard University in Cambridge, Massachusetts, have invented a specialized laser-manufacturing process that allowed them to create tiny composite structures, including mechanical wings and flight muscles. The researchers used the components to build 80-milligram robotic flies with flapping frequency, wing stroke and energy use similar to that of real flies.

 The mechanical flies (pictured) were capable of controlled flight manoeuvres and hovering in place. The work could open the door to additional innovations in miniaturized machines.

Nature 497, 161 (09 May 2013)

Science 340, 603–607 (2013)

BAT GENOMES

Evolution of Flight and Immunity

 

 

 

A juvenile male Pteropus alecto (black flying fox) spreading its wings (for adults, average wing span: ~1 meter; average weight range: 500 to 1000 grams). Bats, the only mammals capable of sustained flight, are among the world's most diverse mammals and are host to numerous deadly viruses. Comparative genome analyses have shed new light on the evolution of bat-specific traits, including flight and immunity. See page 456. Photo: Martin Asser Hansen/www.maasha.dk 

 

Bats are the only mammals capable of sustained flight and are notorious reservoir hosts for some of the world's most highly pathogenic viruses, including Nipah, Hendra, Ebola, and severe acute respiratory syndrome (SARS). To identify genetic changes associated with the development of bat-specific traits, we performed whole-genome sequencing and comparative analyses of two distantly related species, fruit bat Pteropus alecto and insectivorous bat Myotis davidii. We discovered an unexpected concentration of positively selected genes in the DNA damage checkpoint and nuclear factor κB pathways that may be related to the origin of flight, as well as expansion and contraction of important gene families. Comparison of bat genomes with other mammalian species has provided new insights into bat biology and evolution.  

Science 25 January 2013: Vol. 339 no. 6118 pp. 456-460

EL REGRESO DE TRES DINOSAURIOS

1) EL DE TITO MONTERROSO

El dinosaurio
[Minicuento. Texto completo.]

Augusto Monterroso

Cuando despertó, el dinosaurio todavía estaba allí. 

FIN 

 

2) EL DE NATURE

Return of the dinosaur Mongolian researchers have finally got their hands on the Tarbosaurus bataar fossil (pictured) that was illegally smuggled out of Mongolia and came to auction in the United States last year. On 16 April, the team in New York began weighing and measuring the bones of the T. bataar specimen in preparation for customs registration and shipment back to Mongolia, which is expected shortly after it officially becomes Mongolian property on 6 May. The legal status of the fossil had been in limbo since Mongolia disputed its sale for more than US$1 million at a New York auction house last May. The 7.3-metre-long specimen is one of the most complete tyrannosau 

3) EL PRI

Arachnoscelis magnifica

Arachnoscelis magnifica, a predaceous katydid (Orthoptera: Tettigoniidae), on a leaf in the San Lorenzo forest of Panama. This attractive insect is but one of the ~25,000 arthropod species likely to live in this 6000-hectare forest, confirming the formidable diversity of arthropods, which appears to be 300 times that of mammals in tropical rainforests.

DEGRADACIÓN DE LA TIERRA

Drought kills agricultural profit

 

 

Land degradation and desertification are causing huge reductions in agricultural profits in the world’s poorest nations, according to a report presented at the United Nations Convention to Combat Desertification (UNCCD). The first assessment of its kind in more than 20 years calculates that Guatemala, for example, lost 24% of its agricultural gross domestic product to environmental degradation. The findings were presented at the UNCCD’s second scientific conference, on 9 April in Bonn, Germany. Nearly 3.7 million people in East Africa still require food assistance after droughts in Kenya (pictured) and other nations wiped out crops in 2011, the UNCCD says. “Desertification, land degradation and drought are key constraints to building social and environmental resilience, achieving global food security and delivering meaningful poverty reduction,” said UNCCD executive secretary Luc Gnacadja at the meeting.

 

Nature / Seven days: 12–18 April 2013

 

 

NATURAL PRODUCTS EMERGENT

Fermentation rooms, at Warp Drive Bio, could open the door to natural product drug discovery

Natural compounds produced by the world’s microbes were once the go-to source of molecules for the drug industry before the chemistry dried up and big pharma went packing. Now, researchers hope that advances in genomics will bring companies back into the fold.

volume 19 | number 4 | april 2013 nature medicine

MEXICAN ARTIST: ATANASIO ECHEVERRIA

VISIBLE EMPIRE

Botanical Expeditions and visual culture in the hispanic enlightenment

From New Spain.

Mexican artist Atanasio Echeverría's watercolor of Erythrina divaricata.

Science 9 November 2012: Vol. 338 no. 6108 pp. 743-744  BOOKS ET AL.

HISTORY OF SCIENCE

Picturing Nature and Empire

Pamela H. Smith

Visible Empire Botanical Expeditions and Visual Culture in the Hispanic Enlightenment by Daniela Bleichmar University of Chicago Press, Chicago, 2012. 298 pp. $55, £35.50. ISBN 9780226058535.

Molecular therapy

Deafness diverted

Molecular therapy improves hearing and balance in a mouse model of a hereditary disease that causes deafness and balance disorders.

In humans, Usher syndrome is often caused by a mutation in the gene USH1C that results in the production of a truncated form of the protein harmonin — which normally guides development of the inner ear (pictured) — and leads to impaired hearing.

Jennifer Lentz at Louisiana State University in New Orleans, Michelle Hastings at Rosalind Franklin University in North Chicago, Illinois, and their collaborators injected newborn mice with DNA-like molecules that mask the mutation in the cell's protein-expression machinery, causing normal harmonin to be produced. This stopped the loss of inner-ear cells that respond to sound, improved low- and mid-frequency hearing and reduced behaviours associated with balance impairment such as head-tossing and circling. The effects lasted at least six months. The authors suggest that a similar approach may have therapeutic potential in human congenital deafness.

Nature 494, 150 (14 February 2013)

 

 

BOX JELLYFISH

Because most jellyfishes are venomous, they are also called sea wasps or marine stingers. Each tentacle contains more than 100,000 cnidocytes with nematocysts, small needles that inject venom into the victim. The most dangerous species are found in the tropical Indo-Pacific but the Caribbean species can also cause serious injuries. This picture was taken in Guadeloupe (French West Indies) by Dominique Marion, a senior scientist from the Institut de Biologie Structurale in Grenoble, France. Visit his galleries at http://diffraction-marine.net for more underwater pictures.

NEUROCIENCIA DE PECERA

Mapping brain networks

The transparency of zebrafish larvae makes the animals ideal models for seeing deep into tissues. CHARLES MAZEL/VISUALS UNLIMITED/CORBIS

Tiny fish trapped in a virtual world provide a window into complex brain connections.
Virginia Hughes

A recently hatched zebrafish is swimming upriver for the first time. Its big round eyes, bulging on the front of its eyelash-sized body, scan the surroundings. Suddenly, it sees the scenery flying forwards as a gentle current pushes it backwards. The fish flicks its tail to try to stay in place. Or so it thinks.
In reality, the baby fish is paralysed and suspended in a water-filled Petri dish by glass pipettes. The dish sits on the stage of a US$100,000 microscope in the corner of a darkened, cluttered laboratory. A film, projected from below, has transported the fish to a virtual world in which moving bands of light and dark simulate passing underwater scenery.
Although the fish doesn't move, the motor neurons that control its tail are firing away, just as if it were swimming. And when fed into a computer, those signals can control the video display, giving the fish nearly every sign that it is swimming normally. All the while, Florian Engert's microscope peers deep into the fish's tiny, translucent brain to watch neurons glow green as they fire (see ‘A river of deceit’).

Nature 493, 466–468 (24 January 2013)

ECOLOGÍA URBANA

Colillas de Cigarro Repelen Pestes

VÍCTOR ARGAEZ/R. SOC.

 City-dwelling sparrows and finches incorporate the butts of smoked cigarettes into their nests, seemingly to ward off parasitic mites.

 Isabel López-Rull and her colleagues at the National Autonomous University of Mexico in Mexico City found that nests of house sparrows (Passer domesticus) and house finches (Carpodacus mexicanus; pictured) with higher levels of cellulose acetate, a component of cigarette butts, had fewer mites. The researchers attached fibres from either smoked or unsmoked cigarette filters to parasite-attracting heat traps and placed them in 27 sparrow and 28 finch nests. Traps bearing fibres from smoked filters, which contain more nicotine than those of unsmoked ones, captured fewer mites, suggesting that nicotine — and perhaps other compounds in cigarettes — repel the parasites.

Birds have long been known to line their nests with vegetation that deters parasites, and the authors suggest that the use of cigarette butts is an urbanized form of this earlier adaptation.

Biol. Lett. http://dx.doi.org/10.1098/rsbl.2012.0931 (2012)

Research Highlights Nature 492, 156 (13 December 2012)

IN RETROSPECT The Origin of Life

Clifford P. Brangwynne and Anthony A. Hyman celebrate the first book to plausibly suggest how life began.

Aleksandr Oparin (seated) posited that life emerged from compounds in the atmosphere of early Earth.

“No religious or philosophical system, no outstanding thinker ever failed to give this question serious consideration.” So wrote Aleksandr Oparin more than 75 years ago, about the quintessential conundrum of how life self-assembled from inanimate components. The Soviet biochemist’s answer is his book The Origin of Life (1936). Roughly based on a pamphlet he published in 1924, this book is an enormous contribution to our understanding of life’s improbable beginnings. In it, Oparin argues that conditions on early Earth nurtured the synthesis of amino acids and their assembly into protocells.

Tony Hyman. NATURE | VOL 491 | 22 NOVEMBER 2012

CERTAIN NEURONS ARE CRITICAL REGULATORS OF BODY WEIGHT & FOOD INTAKE

a switch between peripheral
carbohydrate and lipid utilization

AgRP/NPY neurons are critical regulators of body weight and food intake. Concordant with their orexigenic effects, it is expected that AgRP ablation leads to the appearance of a lean phenotype. In the current issue of The EMBO Journal, Joly-Amado et al (2012) describe an obese phenotype in a model of AgRP-ablated mice, and link it to a shift in metabolic profile in efferent tissues such as the
liver, muscle and pancreas.

Luis Varela and Tamas L Horvath

The EMBO Journal (2012) 31, 4252–4254.

ASTRONOMY: PICKING OUT A PREDATORY PULSAR

 "Viuda Negra" Convertida en Pulsar

Researchers have used raw computing power to hunt down a 'black widow' pulsar that is evaporating its companion star.

Pulsars are stellar remnants that emit lighthouse-like beams of radiation. They often emit gamma rays, but can usually be spotted only if they also emit easier-to-detect radio waves. However, Holger Pletsch of the Max Planck Institute for Gravitational Physics in Hannover, Germany, and his colleagues found the current pulsar (pictured; circled) through a blind search of data from the Fermi Gamma-ray Space Telescope.

Using computers to analyse huge swathes of raw data, the team picked out the pulsar, which takes 93 minutes to orbit its companion star. This orbital period is the shortest of any binary pulsar of this type yet found.

Nature: 491, 10 (01 November 2012)

ESTRÉS EN LA CIUDAD

Stress and the city: Urban decay

 Scientists are testing the idea that the stress of modern city life is a breeding ground for psychosis.

In 1965, health authorities in Camberwell, a bustling quarter of London's southward sprawl, began an unusual tally. They started to keep case records for every person in the area who was diagnosed with schizophrenia, depression, bipolar disorder or any other psychiatric condition. Decades later, when psychiatrists looked back across the data, they saw a surprising trend: the incidence of schizophrenia had more or less doubled, from around 11 per 100,000 inhabitants per year in 1965 to 23 per 100,000 in 1997 — a period when there was no such rise in the general population (J. Boydell et al. Br. J. Psychiatry 182, 45–49; 2003). The result raised a question in many researchers' minds: could the stress of city life be increasing the risk of schizophrenia and other mental-health disorders?

Nature | News Feature  Alison Abbott 10 October 2012 162 | NATURE | VOL 490 | 11 OCTOBER 2012