Crustaceans go through pubertal molt to provide the animal with features that are distinct to adults. The androgenic gland hormone (AGH) is important for male differentiation and secondary male characteristics. Females lack AGH, so are considered the default sex for development. Previous work has shown that when the eyestalk is ablated in the females of some crab species, mating and maternal care structures show defects; however, the animals are able to molt and develop into giant immature crabs. In studying the blue crab, Callinectes sapidus, Zmora et al. now show that the endocrine system and localized activity of a hormone termed crustacean female sex hormone (CFSH) from the eyestalk ganglia are involved in adult-specific development through the control of the pubertal-terminal molt. When CFSH is eliminated, the brooding features, which are important for mating and brooding large clutches, are abnormal. This work shows that the endrocrine system functions via a female-specific hormone for the development of adult morphological structures associated with female reproduction, i.e., for mating and brooding.
Modeling reveals how the central nervous system systematically chooses optimal muscle responses to maintain balance
The central nervous system (CNS) comprises the brain
and spinal cord, and coordinates all our bodily activities. One of the
functions of the CNS is to choose the most efficient muscle movements in
order to conserve energy and allow the body to move smoothly, and it is
believed that the CNS trains itself through experience to narrow down
the number of options. Fady Alnajjar and colleagues from the Intelligent
Behavior Control Unit of the RIKEN Brain Science Institute have now
modeled the behavior of muscles during balance tests to illustrate how
the human CNS trains itself to maintain balance1.
“Modeling
of the computational mechanisms between the CNS and muscle control,
which we call muscle synergy, is challenging,” explains Alnajjar. “Our
study concerns the muscle synergy behind basic motor skills, such as
maintaining balance, in healthy humans.”
Alnajjar’s
team developed a model of ‘muscle synergy’ by devising two novel
parameters: the synergy stability index (SSI), which measures the
similarities between muscle usage in repeated behaviors and therefore
the stability of the neural command, and the synergy coordination index,
which measures the overall size of the synergy space required to carry
out a movement and therefore the level of coordination between muscles.
The
researchers used these two parameters to measure the interactions
between the human CNS and muscles during balance tests. Eight
participants were asked to stand on a randomly moving platform, using
only their hips and ankles to maintain balance, with electrodes attached
to their major leg and back muscles.
Both
indices were found to successfully characterize the muscle synergy
associated with balance skill. “Participants with strong balancing
ability showed high SSI levels,” notes Alnajjar, “implying that their
CNSs were aware of the best muscle synergy for responding to balance
disturbances. Participants with low balancing ability had low SSI
levels. Also, good balancers used tightly coordinated muscles, resulting
in smoother movements.”
In each case, the CNS
appeared to search for a narrow muscle-synergy space of stable neural
commands and coordinated muscle reactions. In a second set of
experiments using the lowest scorers from round one, each person
completed five more sessions on the balance platform. The participants
showed significant improvement on completion, suggesting that with
training, the CNS can narrow its muscle-synergy space and thus improve
coordination.
Alnajjar hopes that an advanced
version of these indices could be used to develop therapies for
post-stroke motor function recovery as a means of creating targeted,
effective neuro-rehabilitation systems.
Las pulgas de arena Tunga penetrans pasan la mitad de su vida en la tierra y la otra mitad en un una forma de vida, como por ejemplo un pie humano. Las infestaciones - en América del Sur y África subsahariana - pueden producir una condición dolorosa llamada tungiasis que hace que sea difícil caminar y puede conducir a otras infecciones. Pero la enfermedad ha causado escasa atención por parte de los médicos e investigadores que saben muy poco acerca del ciclo de vida de la criatura, incluso que cuando no está en el suelo tiene sexo y fertiliza sus huevos.
Por eso, cuando Marlene Thielecke, estudiante de doctorado de la Universidad Charité de Berlín, estaba estudiando tungiasis en Madagascar, descubrió que ella misma alojaba al parásito, dejó que su propio cuerpo se convierta en un laboratorio para estudiar la criatura.
La hembra inmadura se entierra en la piel de un hospedero a lo largo de 2 semanas, y se hincha hasta un máximo de 10 mm de diámetro. Pronto empieza expulsar huevos, y muere después de 4 a 6 semanas. La única manera de deshacerse de los parásitos es sacarlos de la piel.
Thielecke tomó fotografías regulares de su infestación. La pulga creció con normalidad, pero no estaba poniendo los huevos. Fue extraño - que todavía estaba vivo después de 2 meses (en ese momento ella la extrajo).
La explicación más probable? La pulga nunca fue fertilizada, Thielecke y su tutor, experto en tungiasis, Hermann Feldmeier, llegaron a esa conclusión en un artículo publicado este mes. En la búsqueda de la pulga, Thielecke había tomado precauciones, usar calcetines y zapatos cerrados para protegerse de otras pulgas, incluyendo potencialmente la fertilización de los machos. Esto sugiere una respuesta al enigma de que las pulgas son fertilizadas después de que se incrustan en la piel . http://scim.ag/fleafert
Artist's impression VICTOR HABBICK VISIONS/SPL/Getty
The
defining characteristic of a black hole may have to give, if the two
pillars of modern physics — general relativity and quantum theory — are
both correct.
Notion of an 'event horizon', from which nothing can escape, is incompatible with quantum theory, physicist claims.
Most physicists foolhardy enough to write a paper claiming that “there
are no black holes” — at least not in the sense we usually imagine —
would probably be dismissed as cranks. But when the call to redefine
these cosmic crunchers comes from Stephen Hawking, it’s worth taking
notice. In a paper posted online, the physicist, based at the University
of Cambridge, UK, and one of the creators of modern black-hole theory,
does away with the notion of an event horizon, the invisible boundary
thought to shroud every black hole, beyond which nothing, not even
light, can escape.
In its stead, Hawking’s radical proposal is a much more benign “apparent
horizon”, which only temporarily holds matter and energy prisoner
before eventually releasing them, albeit in a more garbled form.
“There is no escape from a black hole in classical theory,” Hawking told Nature.
Quantum theory, however, “enables energy and information to escape from
a black hole”. A full explanation of the process, the physicist admits,
would require a theory that successfully merges gravity with the other
fundamental forces of nature. But that is a goal that has eluded
physicists for nearly a century. “The correct treatment,” Hawking says,
“remains a mystery.”
Hawking posted his paper on the arXiv preprint server on 22 January1.
He titled it, whimsically, 'Information preservation and weather
forecasting for black holes', and it has yet to pass peer review. The
paper was based on a talk he gave via Skype at a meeting at the Kavli
Institute for Theoretical Physics in Santa Barbara, California, in
August 2013 (watch video of the talk).
Fire fighting
Hawking's
new work is an attempt to solve what is known as the black-hole
firewall paradox, which has been vexing physicists for almost two years,
after it was discovered by theoretical physicist Joseph Polchinski of
the Kavli Institute and his colleagues (see 'Astrophysics: Fire in the hole!').
In
a thought experiment, the researchers asked what would happen to an
astronaut unlucky enough to fall into a black hole. Event horizons are
mathematically simple consequences of Einstein's general theory of
relativity that were first pointed out by the German astronomer Karl
Schwarzschild in a letter he wrote to Einstein
in late 1915, less than a month after the publication of the theory. In
that picture, physicists had long assumed, the astronaut would happily
pass through the event horizon, unaware of his or her impending doom,
before gradually being pulled inwards — stretched out along the way,
like spaghetti — and eventually crushed at the 'singularity', the black
hole’s hypothetical infinitely dense core.
But on analysing the situation in detail, Polchinski’s team came to
the startling realization that the laws of quantum mechanics, which
govern particles on small scales, change the situation completely.
Quantum theory, they said, dictates that the event horizon must actually
be transformed into a highly energetic region, or 'firewall', that
would burn the astronaut to a crisp.
This was
alarming because, although the firewall obeyed quantum rules, it flouted
Einstein’s general theory of relativity. According to that theory,
someone in free fall should perceive the laws of physics as being
identical everywhere in the Universe — whether they are falling into a
black hole or floating in empty intergalactic space. As far as Einstein
is concerned, the event horizon should be an unremarkable place.
Beyond the horizon
Now
Hawking proposes a third, tantalizingly simple, option. Quantum
mechanics and general relativity remain intact, but black holes simply
do not have an event horizon to catch fire. The key to his claim is that
quantum effects around the black hole cause space-time to fluctuate too
wildly for a sharp boundary surface to exist.
In
place of the event horizon, Hawking invokes an “apparent horizon”, a
surface along which light rays attempting to rush away from the black
hole’s core will be suspended. In general relativity, for an unchanging
black hole, these two horizons are identical, because light trying to
escape from inside a black hole can reach only as far as the event
horizon and will be held there, as though stuck on a treadmill. However,
the two horizons can, in principle, be distinguished. If more matter
gets swallowed by the black hole, its event horizon will swell and grow
larger than the apparent horizon.
Conversely,
in the 1970s, Hawking also showed that black holes can slowly shrink,
spewing out 'Hawking radiation'. In that case, the event horizon would,
in theory, become smaller than the apparent horizon. Hawking’s new
suggestion is that the apparent horizon is the real boundary. “The
absence of event horizons means that there are no black holes — in the
sense of regimes from which light can't escape to infinity,” Hawking
writes.
“The picture Hawking gives sounds
reasonable,” says Don Page, a physicist and expert on black holes at the
University of Alberta in Edmonton, Canada, who collaborated with
Hawking in the 1970s. “You could say that it is radical to propose
there’s no event horizon. But these are highly quantum conditions, and
there’s ambiguity about what space-time even is, let alone whether there
is a definite region that can be marked as an event horizon.”
Although
Page accepts Hawking’s proposal that a black hole could exist without
an event horizon, he questions whether that alone is enough to get past
the firewall paradox. The presence of even an ephemeral apparent
horizon, he cautions, could well cause the same problems as does an
event horizon.
Unlike the event horizon, the
apparent horizon can eventually dissolve. Page notes that Hawking is
opening the door to a scenario so extreme “that anything in principle
can get out of a black hole”. Although Hawking does not specify in his
paper exactly how an apparent horizon would disappear, Page speculates
that when it has shrunk to a certain size, at which the effects of both
quantum mechanics and gravity combine, it is plausible that it could
vanish. At that point, whatever was once trapped within the black hole
would be released (although not in good shape).
If
Hawking is correct, there could even be no singularity at the core of
the black hole. Instead, matter would be only temporarily held behind
the apparent horizon, which would gradually move inward owing to the
pull of the black hole, but would never quite crunch down to the centre.
Information about this matter would not destroyed, but would be highly
scrambled so that, as it is released through Hawking radiation, it would
be in a vastly different form, making it almost impossible to work out
what the swallowed objects once were.
“It
would be worse than trying to reconstruct a book that you burned from
its ashes,” says Page. In his paper, Hawking compares it to trying to
forecast the weather ahead of time: in theory it is possible, but in
practice it is too difficult to do with much accuracy.
Polchinski,
however, is sceptical that black holes without an event horizon could
exist in nature. The kind of violent fluctuations needed to erase it are
too rare in the Universe, he says. “In Einstein’s gravity, the
black-hole horizon is not so different from any other part of space,”
says Polchinski. “We never see space-time fluctuate in our own
neighbourhood: it is just too rare on large scales.”
Raphael
Bousso, a theoretical physicist at the University of California,
Berkeley, and a former student of Hawking's, says that this latest
contribution highlights how “abhorrent” physicists find the potential
existence of firewalls. However, he is also cautious about Hawking’s
solution. “The idea that there are no points from which you cannot
escape a black hole is in some ways an even more radical and problematic
suggestion than the existence of firewalls,” he says. "But the fact
that we’re still discussing such questions 40 years after Hawking’s
first papers on black holes and information is testament to their
enormous significance."
Portada de la revista Science del 18 de Octubre de 2013, que nos muestra la caleta completa encontrada en Dmisisi Georgia de un Homo de 1.77 millones de años de edad y que nos recuerda el origen de nuestra humanidad.
Peer carefully at the lower right of this image and you might just spot the tiny dot that is Earth, seen from more than a billion kilometres away. This vista of Saturn’s famous rings backlit by the Sun was assembled from 141 individual images taken by NASA’s Cassini probe after it moved into Saturn’s shadow in July.
FIRE IN THE SKY
This huge fireball was created by the largest meteor known to hit Earth since the Tunguska rock landed in 1908. Russia was once again the unlucky recipient: the meteor exploded some 30 kilometres above Chelyabinsk in the Urals and shone brighter than the Sun.
BONUS ONLINE-ONLY EDITORS’ CHOICE
Although this image didn’t make our end-of-year print piece, it captivated our selection team. It shows Terry Headley, a volunteer with the University of Minnesota Raptor Center, rescuing an injured bald eagle in April.
365 days: Images of the year http://www.nature.com/news/365-days-images-of-the-year-1.14303
Ciertos sintomas de la esquizofrenia pueden surgir de la activación incontrolada de neuronas que ayudan a construir recuerdos durante los períodos de descanso.
Mapa de la actividad neuronal durante el descanso, en ratones deficientes de calcineurina. Comparativamente, en los ratones normales, el mapa revela patrones de encendido de neuronal complejos, los cuales están ausentes en el modelo de esquizofrenia de ratón.
When viruses (green) attack bacteria, the bacteria respond with DNA-targeting defenses that biologists have learned to exploit for genetic engineering.
CREDIT: EYE OF SCIENCE/SCIENCE SOURCEScience 23 August 2013: Vol. 341 no. 6148 pp. 833-836
By scanning blobs of brain activity, scientists may be able to decode people's thoughts, their dreams and even their intentions.
Anne Hathaway's face appears in a clip from the film Bride Wars,
engaged in heated conversation with Kate Hudson. The algorithm
confidently labels them with the words 'woman' and 'talk', in large
type. Another clip appears — an underwater scene from a wildlife
documentary. The program struggles, and eventually offers 'whale' and
'swim' in a small, tentative font.
Possible infection with the MERS coronavirus, or a closely related virus, has been detected in camels.
Frank Krahmer/Getty
A year on from the first reported human case of infection with Middle
East respiratory syndrome coronavirus (MERS-CoV), the world still has
few answers to the most pressing question from a public-health
perspective: what is the source of the steady stream of new cases? Only
with this information can the outbreak be controlled.
There have so far been 114 confirmed cases of MERS-CoV infection, including 54 deaths, with another 34 suspected cases (see ‘Catching on’).
All originated in the Arabian Peninsula, with most in Saudi Arabia and
others in Jordan, Qatar and the United Arab Emirates (UAE). Imported
cases have occurred in the United Kingdom, France, Italy and Tunisia.
The virus is thought to be an animal virus that sporadically jumps to
people — there are no signs yet that it can spread easily between
humans, although limited spread between people in close contact has been
seen.
Five European individuals who lived during the Middle Ages provide a look backwards at leprosy
Leprosy was endemic in Europe until the Middle Ages. Using DNA array capture, we have obtained
genome sequences of Mycobacterium leprae from skeletons of five medieval leprosy cases from the
United Kingdom, Sweden, and Denmark. In one case, the DNA was so well preserved that full de novo
assembly of the ancient bacterial genome could be achieved through shotgun sequencing alone.
The ancient M. leprae sequences were compared with those of 11 modern strains, representing
diverse genotypes and geographic origins. The comparisons revealed remarkable genomic conservation
during the past 1000 years, a European origin for leprosy in the Americas, and the presence of an
M. leprae genotype in medieval Europe now commonly associated with the Middle East. The exceptional
preservation of M. leprae biomarkers, both DNA and mycolic acids, in ancient skeletons has major
implications for palaeomicrobiology and human pathogen evolution. Science 341, 179 (2013)
Last summer, it looked like the Voyager 1
spacecraft might have finally reached its ultimate destination.
Thirty-five years
out from Earth and three times farther
from the sun than Pluto, the decrepit spacecraft reported a sharp drop
in plasma blowing
out from the sun and a sharp jump in
cosmic rays streaming in from out in the galaxy.
But three papers published online this week in Science
conclude that Voyager 1 has not left the heliosphere—the sun's magnetic
bubble inflated by its blowing plasma—and entered
interstellar space. That's because Voyager
found no accompanying switch from the magnetic field spiraling out from
the sun
to the magnetic field of interstellar
space.
Instead, Voyager
has discovered a hybrid part of the heliosphere lying between the
heliosphere proper and true interstellar
space. And nobody knows how far that
hybrid extends and when the spacecraft will actually make humankind's
first contact with
interstellar space.
Science. Volume 340, Number
6140, Issue of 28 June 2013
A magenta exoplanet 17.5 parsecs from Earth is the lowest-mass planet that has ever been directly imaged orbiting a Sun-like star outside the Solar System, NASA announced last week. The Subaru Telescope on Mauna Kea, Hawaii, took pictures of the exoplanet GJ 504b at near-infrared wavelengths with the help of adaptive optics. GJ 504b is four times more massive than Jupiter and, with a surface temperature of 237 °C, still glows pink from its fiery birth 160 million years ago. The rosy planet (pictured in an artist’s impression) orbits the star GJ 504, which can be seen with the naked eye, in the constellation Virgo. With an orbiting radius 43.5 times Earth’s distance from the Sun, GJ 504b challenges current theories of how far away from stars large planets form. The findings will be published in The Astrophysical Journal.
Not only are beetles among the most diverse group of animals on Earth, but some rival the most flamboyant birds and dazzling coral reef fish with their metallic sheens. Researchers have now traced the evolutionary history of this iridescence in one group of beetles, the weevils, and identified an unexpectedly varied assortment of complex light-altering crystals in the insects. The new work also shows that these diverse crystal architectures all share a single origin in these beetles' evolutionary past. Weevils "have developed high crystal diversity from a relatively modest tool kit," says Ainsley Seago, a systematist with the Australian National Insect Collection in Canberra, who led the work.
Cuando platique con el celebre biologo mexicano y del mundo, Toño Lazcano
Araujo, de la posibilidad de que nos visitara Stanley Miller, aquel inquieto
estudiante graduado de la Universidad de Chicago que había logrado
convencer al Doctor Harold Urey de reproducir en una probeta las condiciones
que pudo haber tenido la atmósfera primitiva de nuestro planeta, nunca
pense en lo grato que resultaría en muchos sentidos.
En primer lugar, en esta casa de trabajo, ARMARIO, todos, especialmente
Arturo Chavolla, Cuahtemoc Vite y Maria Luisa Franco me brindaron toda
clase de apoyo en relación a la posibiliad de que un suplemento cultural,
dedicara, nada menos que todo el número de hoy a un tema que la cultura
frecuentemente relega a un segundo o tercer plano o bién ni siquiera
considera como importante: La divulgación de un tema científico
En segundo lugar, cuando invité a Javier Ruíz de la Presa a escribir sobre
este tema, de inmediato le pareció interesante y hasta estímulante y escribió
una colaboración esplendida de la Evolución de la Vida desde “Una
perspectiva filosófica”, lo cual une a estas dos partes de la Ciencia la
biológica y la humanística, cosa a veces tan dificil de integrar en este
fragmentado mundo posmoderno.
Después al hablar con el naturalista jaliscience y Doctor Enrique Estrada
Faudon, fué tan amable, que me pareció que la empresa de hacer este
número iba a lograrse; Resulta que el Doctor Estrada Faudon es uno de los
personajes de las ciencias naturales que ha dado el occidente del país; su
experiencia con aspecto juvenil, lo hace imprescindible cuando uno quiere
conocer algun aspecto del desarrollo de la Botánica o Geografía del estado de
Jalísco. Gracias al Doctor Estrada Faudón presentamos algunas ilustraciones del biólogo mexicano Alfonso L
Herrera, que por los años treintas, en plena época cristera, andaba
publicando en las mejores revistas francesas los últimos avances de la
Biología logrados en su propio laboratorio de la colonia Santa María en la
Ciudad de México y en relación con la Plasmogénia o aparición de las primeras
formas vivas sobre el planeta.
Por supuesto la aparición de los textos de Miller por un lado y Lazcano por
otro, ilustran de manera impecable como la vida sobre la Tierra pudo haber
surgido hace unos cuatro mil millones de años y además como esas primeras
formas vivas empezaron a desarrollarse, lo cual fué perfectamente captado
por JIS en su celebre cartón que dedica en exclusiva a este númeto especial.
Precisamente su señor padre el Ingeniero Federico Solorzano, catedrático de
“Prehistoria” en el Centro Universitario de Ciencias Sociales y Humanidades,
de la Universidad de Guadalajara, nos hace un estupendo recuento de las
últimas fases de la evolución: La Evolución de los hominidos precursores del
Homo sapiens contemporaneo, discutiendo cuales de los restos arqueológicos
de hace unos cien mil años, actualmente encontrados en diversas partes del
mundo, corresponde al abuelo del hombre del siglo XXI .
Por último Ulises Iñiguez Mendoza aceptó con amabilidad el reto de colaborar
también en este número, desde la perspectiva del cine: Se plantea en su
docta colaboración que diferentes cineastas, uno inglés y otro ruso (Kubrick
y Tarkovski), de algún modo hicieron una importante incursión en el tema de
este número monográfico, por medio de sus obras maestras: 2001: “Una
Odisea del Espacio” y “Solaris” respectivamente, demostrando que la cultura
es un todo diverso en donde la ciencia y sus ideas permean a todo el actuar
humano.
Esperamos que este acontecimiento del número monográfico sea el primero
de una serie de números en donde la sociedad intelectual y el ciudadano se
enlacen para demostrar que el nivel del periodismo cultural no solo lo
constituyen la nota roja y la política sino que también hay sed de ciencia en la
comunidad de nuestra región. Enhorabuena.
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.
The subependymal zone (SEZ) is a neurogenic niche that gives rise to adult-born neurons. Paez-Gonzalez and colleagues describe a population of cholinergic neurons in this region that modulates neural progenitor proliferation. The cover depicts a SEZ cholinergic neuron (red) along with surrounding stem cells and newborn neuroblasts (teal). Cover image by Chay Kuo. (pp 897 and 934) July 2014 Volume 17 No 7
NEUROSCIENCE
Enzyme duo elicit nerve branching.- A pair of enzymes control where synapses form in neurons by guiding the transport of energy-producing organelles called mitochondria. A team led by Franck Polleux at the Scripps Research Institute in La Jolla, California, identified two enzymes that are required for axons (the long message-transmitting stalks of neurons) to branch and form synapses with other neurons. When these enzymes were overexpressed in neurons, mitochondria moving down the axon, along microtubules, were immobilized at the point where axons would form synapses. Higher levels of these enzymes boosted axon branching (pictured), whereas lower levels reduced it. The researchers suggest that the two enzymes work together to tell mitochondria where to stop and thus where synapses will form. Mitochondrial transport could factor in the development of a wide range of disorders, including autism, through its effects on synapse formation, the authors say.
Massive meteor strike
The Russian city of Chelyabinsk was rocked by the shock wave from a massive meteor that broke up high above the city on 15 February. More than 1,000 people were injured by flying glass as windows shattered throughout the city. Data from the Comprehensive Test Ban Treaty Organization show that the explosion was the equivalent of around half a megatonne of TNT. That would correspond to a meteoroid around 17 metres across and weighing 10,000 tonnes. It is believed to be the largest object to strike Earth since a massive body broke up over the Tunguska river in Siberia in 1908. See go.nature.com/yxeiwq and page 281 for more.
EVENTS NASA snaps Earth at night
Almost exactly 40 years after Apollo 17 astronauts took the iconic Blue Marble photograph of Earth, NASA has released a spectacular view of the planet at night, appropriately named Black Marble. The views, unveiled on 5 December, were stitched together from images taken by a high-resolution sensor aboard the Suomi National Polar-orbiting Partnership weather satellite. Data from the new sensor could be used as a proxy for factors such as population distribution and carbon emissions. See go.nature.com/jfv8ql for more.
PERCEPCIÓN
Facing reality: In the human brain, parts of the fusiform gyrus respond strongly and selectively when a person sees a face, and damage to the fusiform gyrus can impair face perception or naming. Nature Reviews Neuroscience 13, 812-813 (December 2012) |
Alfonso Islas/
Profesor Investigador Titular C de la Universidad de Guadalajara.
Profesor del Posgrado en Ciencias Biomédicas CUCS-CUCBA, con registro en el Padrón de Excelencia del CONACyT
Ubicación: Mexico
Doctor en Ciencias Biomédicas por la UNAM.
Profesor de la Maestría en Comunicación de la Ciencia y la Cultura con registro en el Padrón de Excelencia del CONACyT, del ITESO.
Miembro del Sistema Nacional de Investigadores de 1985 a 1997.
He publicado más de 40 artículos científicos en Revistas nacionales e internacionales.
Jefe del Departamento de Biología Celular y Molecular en 1994-1995.
Director de la División de Ciencias Biológicas 1995-1998.
Jefe de Investigación y Posgrado de la de la UdeG de 1998 a 2000.
Columnista de:
Siglo 21 (1993).
Armario de El Occidental1995-2000).
MURAL del grupo REFORMA (2000-2009).
He publicado en diferentes revistas culturales como Complot, Tragaluz, Replicante, Luvina y recientemente en otras academicas como Renglones (ITESO)
Intereses:
Ciencia, Cine, Literatura.
Películas favoritas
Movie-Art: Metropolis-Fritz Lang
Researchers in Massachusetts have found a way to extract power from the ear. Konstantina Stankovic of the Massachusetts Ear and Eye Infirmary in Boston, Anantha Chandrakasan at the Massachusetts Institute of Technology in Cambridge and their colleagues developed a chip (pictured) that can exploit the inner ear's electrical potential, which is generated to convert sound into neural impulses. The team inserted electrodes from the chip through a natural opening into the inner ear of an anaesthetized guinea pig. The chip extracted around 1 nanowatt of power for up to five hours — enough to power a small radio transmitter. The system could eventually be used to harvest power for devices that diagnose and treat hearing loss in humans, the authors suggest.
BAJO LOS CIELOS AFRICANOS
Gavin Jantjes’ untitled painting depicts a Khoisan girl creating the Milky Way
Galileo xplorador de la conciencia
Galileo Galilei, pictured centre, after a painting by H. J. Detouche, is imagined in Giulio Tononi’s Phi as an explorer of consciousness
Sustainability
The shoe firm Puma has taken innovative steps towards disclosing its environmental impact. Sustainability: The corporate climate overhaul
Microorganíamos de una muestra tomada en el Lago Washington (Seattle), son trending topic este mes.
SPACE WEATHER
Space weather, which sometimes causes auroras on Earth, threatens to play havoc with electrical grids and to disrupt signals from the Global Positioning System.
LUZ EN LA OSCURIDAD
From fish to squid, marine creatures have evolved sophisticated ways to make, use, and perceive light, inspiring researchers interested in optics and animal ecology and behavior
In this octopus, Stauroteuthis syrtensis, suckers have evolved into light organs, possibly used to lure in prey.
In the dark deep, the burglar alarm jellyfish lights up blue (far left) to call in predators of its attackers; researchers copied this pattern with LEDs (near left) to lure organisms to an underwater camera.
Transparent organisms still reflect polarized light (lower right), possibly losing their camouflage.
Researchers hope one day to tap the unique yellow bioluminescence of this polychaete for cell-labeling studies
Computer simulations (above) show that the iridescent cells (blue) that make giant clams colorful form a layer that transmits light to columns of algae (green) deeper down
Transparent organisms are invisible in downwelling light but can be seen by fish with bioluminescent searchlights red-pigmented animals have the reverse problem. But a transparent squid and octopus (above, far right) turn red rapidly when hit with a searchlight, remaining invisible.
CRÉDITOS
EDITH WIDDER, S. ZYLINSKI , ALISON M. SWEENEY, B. STRAUCH, S. JOHNSEN.
NEWS FOCUS Light in the Deep 9 MARCH 2012 VOL 335 SCIENCE: 1160
OTRO PRESENTE RECORDADO
¡Espacio, puro espacio, nulo y vacio! Estoy aquí, pero también estoy allá, todo es aquí, todo es allá. Estoy en cualquier punto eléctrico del espacio y en cualquier fragmento imantado del tiempo: ayer es hoy; mañana, hoy; todo lo que fue, todo lo que será, está siendo ahora mismo, aquí en la Tierra o allá, en la estrella. Octavio Paz. La Hija de Rappaccini (1956)
Vistas a la página totales
ASTRONOMÍA: UNA NUEVA CLASE DE PLANETAS
John Southwort de Nature nos cuenta, que han sido descubiertos tres ejemplos de una nueva familia de planetas, que en vez de orbitar un solo Sol, lo hacen alrededor de dos. La Vía Láctea puede contener millones de estos circumbinarios planetas / Referencia / Nature: 481, 448–449 (26 January 2012)
The Fukushima accident led to mass evacuations from nearby towns such as Minamisoma
LARGA VIDA
Envejecimiento evitable: Generaciones longevas Susan E. Mango
La extensión de la vida de algunos organismos puede ser extendida por medio de mutaciones que alteran el modo de como el DNA es empacado en las células. Un estudio revela que sus efectos pueden durar varias generaciones aún en desendientes geneticamente normales. (Ver artículo p.365)
Nature 479, 302–303 (17 November 2011) doi:10.1038/479302a
"Lab heads also need to ensure that their younger lab members maintain a sense of autonomy rather than of cog-in-the-machine" (Nature 24/7; 1 de Septiembre 2011)
y De parte de Alejandro Rozado:
NOSTALGIA DE DON QUIJOTE: "(...) defender las doncellas, amparar a las viudas, socorrer a los huérfanos y a los menesterosos". Alejandro
Mensajes Inmediatos
First Stars Were Spinning Tops
The first stars, which were up to hundreds of times bigger than the sun, were also whirling at incredible speeds, suggests a new study.
Al fin, La sonda satelital gravitacional "B", Prueba que Einstein Estaba en lo Corrercto
Old Spiders Weave Messy Webs
In humans, we associate getting older with cobwebs of the mind; in spiders, it's the cobwebs themselves that suffer. left photo, built by a 17-day-old spider. The web in the right photo was built by a 188-days-old spider nearing the end of its life
Exhuberancia
En el orden de las manecillas del relog: Cladanora benitezi; Unbelligerus peruviensis; Nassenia binotata y una nifa de Cymbomorpha
Jellyfish eyes on the sky
Box jellyfish seem to have eyes that peer constantly upwards, allowing them to navigate by detecting features on land.
Pánico en Japón
Choque de Placas
Olas de Dsectrucción
El Cerebro en una Cascara de Nuez
Autopsy in a Nutshell (2006) exploits more than the visual similarity between the brain and a walnut, as revealed on closer inspection (bottom).
Izabella Godlewska de Aranda's painting Cosmic Joy! (2009) hints at the idea of many universes
La Académia de Ciencias de Estados Unidos Convoca a la Investigación "Bipolar"
Pingüinos Adélie de la Antarctica son expulsados de su área natural, debido a las temperaturas más tibias que afectan su cadena alimenticia.
The reefs of the Phoenix Islands in Kiribati are part of the world’s largest marine protected area.
Los Muchos Estilos del Esperma
De todos los tipos celulares del reino animal, los más diversos son los espermas, los cuales pueden estar adornados con tallos, pelos chinos y más.
Romance Radioactivo
El escritor y artísta Lauren Redniss publica una biografía poco convencional de los esposos Marie y Pierre Curie.
El Químico Escéptico
Lejos de definir a los elementos químicos, Robert Boyle dudó de su existencia.
Detector de Neutrinos puesto a 2.5 Km de profundidad en la Antártida
El Detector Final: terminado y sellado, puesto a funcionar.
Mimica del Pez Gato
Mutualism can be a double-edged sword if the animals concerned also compete for food. This may explain the discovery that catfish mimics in the Amazon rarely engage in mimicry with related species.
Cuento Retorcido a la Izquierda
Mandibula de una Serpiente (Pareas iwasakii), con dientes extras en la parte inferior, predador de caracoles con concha con vuelta a la derecha, permitió la emergencia de los caracoles con vuelta a la izquierda
BELLEZA ROBADA
Maximum projection image of a confocal stack of a mitotic cycle 14 Drosophila melanogaster embryo using in situ hybridization to visualize mRNA expression of the gap gene giant (red) and the pair-rule gene even-skipped (blue), with Sytox Green (Invitrogen) used to localize nuclei. Specimen preparation and imaging by Cecelia Miles, Dr. Martin Kreitman's lab; projection and cover design by Dr. Vytas Bindokas; University of Chicago, USA.
Arsénico y Encaje
The cells’ large vacuoles may indicate that they are sequestering arsenic.
Neurociencia: Patrones Cerebrales
Los Disturbios Visuales como éste, vistos por algunas personas que padecen migrañas, pueden ser modelados matemáticamente.
Sexy circuits
As in humans, the actions and reactions of male and female fruitflies during courtship are quite distinct. The differences seem to lie in gender-specific neural interpretations of the same sensory signals.
Felipe Calderón muy Verde
Por cierto el presidente Calderón, declaró ayer que si no fuera presidente sería ecologísta. Además dijo, que hay que avanzar en Cancún, para que la única humanidad que existe se salve. Omite el presidente al resto de las especies sobre el planeta.
Efectivamente está muy verde en los conceptos de la Ecología.
Efecto de la Contaminación sobre la Piel, haciendola más vieja.
Father of fractals Mathematician Benoît Mandelbrot
Widely known as the father of fractal geometry, died on 14 October, aged 85. Working at IBM's research labs at Yorktown Heights in New York from 1958, he discovered the mathematical formulae that describe fractal shapes
Elemental shift for kilo
A precise atom count could usurp antique mass standard
CONFORMACIÓN PLÁSTICA DEL AGUA
"Nunca entederemos la Biología, hasta que entendamos al Agua."
Michael Faraday
Físico y Químico británico, nació el 22 de Septiembre de 1791, en Newington, Surrey, Inglaterra. Sus muchos experimentos contribuyeron grandemente al entendimieto del electromagnetismo. Faraday, s econviertió en un gran científico del siglo 19, inició su carrera como químico. Escribió un manual que muestra su destreza en la técnica y el arte, descubrió un número de compuestos orgánicos, entre otros el benceno, y fue el primero en licuar “permanentemente” un gas. Su principal contribución a la ciencia fue, sin embargo, en el campo de la electricidad y el magnetismo. Fue el primero en producir una corriente eléctrica a partir de un campo magnético, inventó el primer motor eléctrico y el dínamo, demostró la relación entre electricidad y enlace químico, descubrió el efecto del magnetísmo en la luz, y descubrió y nombró el diamagnetísmo. Además realizó los experimentos y formulo la teoría con los cuales James Clerk Maxwell estableció la teoría clásica acerca del campo electromagnético.
Moby Dick
Los Humanos hemos reducido la abundancia de muchos vertebrados marinos, incluidas las ballenas, y los tiburones, a solo pequeños porcentajes de sus niveles pre-industriales preferentemente por la pesca desmedida. Se consideran en este artículo las consecuencias de haber removido a estos animales del oceano, eliminando la posibilidad de atrapar carbono, acción útil para abatir el cambio climático.
CONTROL DEL CANCER DE PIEL
B-RAF es el nombre de una proteína que en el caso de los cánceres humanos y en especial del melanoma, esta mutada y por ello el melanocito normal se convierte en invasivo melanoma. Ahora, se reporta el hallazgo de que estos tumores son sensibles a un nuevo fármaco, llamado PLX4032, lo cual ofrece muchas expectativas para el tratamiento del cáncer.
Biología Evolucionaria
Pez elefante - Campylomormyrus rhynchophorus, que puede ayudar a entender como evolucionan las especies comunicandose entre si.
EFEMÉRIDES
John Dalton English scientist John Dalton, born this day (or September 5) in 1766, was a pioneer in the development of modern atomic theory and was considered by some contemporaries as the “father” of both meteorology and chemistry.
EMBRIÓN EN ACCIÓN
Science 329, 967–971 (2010): Ahora se puede disfrutar de esta secuencia en el tiempo, de nuevos detalles acerca del embrión del pez zebra, conforme se van iniciando sus primeras diez divisiones.
“Por más de 10,000 años, los perros han sido el mejor amigo del hombre"
“Los Perros son el único modelo natural para el estudio de desordenes psiquiátricos.”
Nature Neuroscience y Biotechnology
Una representación del virus HIV sobre la superficie de un linfocito T, generada por computadora, muestra la propuesta de Holt et al. de bloquear la entrada a la sangre, al agente causal del SIDA por medio del uso de la enzima llamada dedos de zinc que noquea al receptor del virus CCR5, presente en las células semilla hematopoyecticas en la página (p 839), se puede ver el artículo Credit: ANIMATE4.com/SciencePhotoLibrary
http://0-www.nature.com.fama.us.es/nbt/journal/v28/n8/covers/largecover.gif Nicholas Spitzer y colaboradores demostraron bellas neuronas piramidales en la portada de Nature Neuroscience de Agosto de 2010. (p 944)
"Una inteligencia que en un momento determinado conociera todas las fuerzas que animan a la naturaleza, así como la situación respectiva de los seres que la componen, si además fuera lo suficientemente amplia como para someter a análisis tales datos, podría abarcar en una sola fórmula los movimientos de los cuerpos más grandes del universo y los del átomo más ligero; nada le resultaría incierto y tanto el futuro como el pasado estarían presentes ante sus ojos"
Ensayo filosófico sobre las probabilidades (1814) Pierre-Simon Laplace (1749-1827)
Cosmos
DESPUES DEL BIG BANG
Grabado alemán que representa a Arquímedes en la Bañera
La UNAM, prestigio popular y público
El Rector Narro recibe el Premio Principe de Asturias: Comunicación y Humanidades. Sin la UNAM, nuestro país probablemente sería ya, tal como Felipe Calderon desea, Mecsicou. Por cierto, ni Zedillo, menos Fox ni Calderón son universitarios, o sea que su concepción de país y cultura es, sabe que modo.
Somos una sociedad que recompensa generosamente a quienes nos hacen más pobres.
Paul Krugman premio nobel de economía 2008
¿deben los científicos más destacados, esos que iluminan los caminos de la investigación científica, dedicar algún tiempo a escribir libros de divulgación científica, tarea que puede "desviarlos" de practicar las habilidades por las que son preciosos?
Clade C es el subtipo más prevalente de HIV-1 en el mundo. La estructura cristalina del núcleo de clade C gp120 es descrito por Bjorkman y colegas, en conjunto con el complejo CD4 y el receptor CD4 - inducidos por anticuerpo. El trabajo revela que el anticuerpo hace contacto con ambos, gp120 y CD4. La portada de la revista muestra una escultura de vidrio de una partícula viral realizada por el artistaLuke Jerram (http://www.lukejerram.com/projects/glass_microbiology).pp 608–613
Bien Dotados
De la Biología evolutiva, la gran variación en el tamaño de los genitales en los animales queda definido en el caso del mosquito Gambusia holbrooki, cuyos miembros femeninos de su especie prefieren machos con genitales grandes para copular. De acuerdo a Andrew Kahn y su equipo de colaboradores de la Universidad Australiana de Camberra para estas femeninas, más grande es mejor.
Referencia EVOLUTIONARY BIOLOGY Well endowed Biol. Lett. doi:10.1098/rsbl.2009.0637 (2009)
Capullo Cósmico
El nacimiento de una enana blanca
Tema Reservado
La Fuente de Marcel Duchamp
Precisamente uno de mis seguidores (ver más abajo), dedicó su columna periodística de la semana que termina a un tema, en mi opinión reservado, ¿Ustedes que opinan?
Sigueme
Arquímedes en la Tina invita a participar al que quiera darse un baño de ciencia y polémica.
Galileo Galilei
Nació en Pisa, el 15 de febrero de 1564. Murió en Florencia, el 8 de enero de 1642. Fue un astrónomo, filósofo, matemático y físico que estuvo relacionado estrechamente con la revolución científica. Eminente hombre del Renacimiento, mostró interés por casi todas las ciencias y artes (música, literatura, pintura). Sus logros incluyen la mejora del telescopio, gran variedad de observaciones astronómicas, la primera ley del movimiento y un apoyo determinante para el copernicanismo. Ha sido considerado como el "padre de la astronomía moderna", el "padre de la física moderna" y el "padre de la ciencia". Su trabajo experimental es considerado complementario a los escritos de Francis Bacon en el establecimiento del moderno método científico y su carrera científica es complementaria a la de Johannes Kepler. Su trabajo se considera una ruptura de las asentadas ideas aristotélicas y su enfrentamiento con la Iglesia Católica Romana suele tomarse como el mejor ejemplo de conflicto entre la autoridad y la libertad de pensamiento en la sociedad occidental.
Controvertido
Galileo ante el Santo Oficio: A pesar de pasar dos meses removiendo cielo y tierra para impedir lo inevitable, es convocado el 16 de febrero de 1616 por el Santo Oficio para el examen de las proposiciones de censura. Fue una catástrofe para él. La teoría copernicana fue condenada. El 25 de febrero y 26 de febrero de 1616, la censura es ratificada por la Inquisición y por el papa Pablo V.
Interesante que incursiones en lugares insospechados, pero, en mi opinión ello está reservado a maestros como Marcel Duchamp. Esta bien, es bueno evocar.
Marcel Duchamp, 28 de julio de 1887 - Neully-sur-Siena, 2 de Octubre de 1968). Artista y ajedrecista francés, cuya obra ejerció una fuerte influencia en la evolución del arte de vanguardia del siglo XX.
