www.transicionestructural.NET es un nuevo foro, que a partir del 25/06/2012 se ha separado de su homónimo .COM. No se compartirán nuevos mensajes o usuarios a partir de dicho día.
0 Usuarios y 1 Visitante están viendo este tema.
Brain Scientists Finally Discover the Glue That Makes Memories Stick For a LifetimePosted by BeauHD on Wednesday August 28, 2024 @11:30PM from the key-chemical-players dept.An anonymous reader quotes a report from Scientific American, written by science journalist Simon Makin:CitarThe persistence of memory is crucial to our sense of identity, and without it, there would be no learning, for us or any other animal. It's little wonder, then, that some researchers have called how the brain stores memories the most fundamental question in neuroscience. A milestone in the effort to answer this question came in the early 1970s, with the discovery of a phenomenon called long-term potentiation, or LTP. Scientists found that electrically stimulating a synapse that connects two neurons causes a long-lasting increase in how well that connection transmits signals. Scientists say simply that the "synaptic strength" has increased. This is widely believed to be the process underlying memory. Networks of neural connections of varying strengths are thought to be what memories are made of.In the search for molecules that enable LTP, two main contenders emerged. One, called PKMzeta (protein kinase Mzeta), made a big splash when a 2006 study showed that blocking it erased memories for places in rats. If obstructing a molecule erases memories, researchers reasoned, that event must be essential to the process the brain uses to maintain memories. A flurry of research into the so-called memory molecule followed, and numerous experiments appeared to show that it was necessary and sufficient for maintaining numerous types of memory. The theory had a couple of holes, though. First, PKMzeta is short-lived. "Those proteins only last in synapses for a couple of hours, and in neurons, probably a couple of days," says Todd Sacktor, a neurologist at SUNY Downstate Health Sciences University, who was co-senior author of the 2006 study. "Yet our memories can last 90 years, so how do you explain this difference?" Second, PKMzeta is created in cells as needed, but then it has to find the right synapses. Each neuron has around 10,000 synapses, only a few percent of which are strengthened, says neuroscientist Andre Fenton, the other co-senior author of the 2006 study, who is now at New York University. The strengthening of some synapses and not others is how this mechanism stores information, but how PKMzeta molecules accomplish this was unknown.A new study published in Science Advances by Sacktor, Fenton and their colleagues plugs these holes. The research suggests that PKMzeta works alongside another molecule, called KIBRA (kidney and brain expressed adaptor protein), which attaches to synapses activated during learning, effectively "tagging" them. KIBRA couples with PKMzeta, which then keeps the tagged synapses strengthened. Experiments show that blocking the interaction between these two molecules abolishes LTP in neurons and disrupts spatial memories in mice. Both molecules are short-lived, but their interaction persists. "It's not PKMzeta that's required for maintaining a memory, it's the continual interaction between PKMzeta and this targeting molecule, called KIBRA," Sacktor says. "If you block KIBRA from PKMzeta, you'll erase a memory that's a month old." The specific molecules will have been replaced many times during that month, he adds. But, once established, the interaction maintains memories over the long term as individual molecules are continually replenished. [...]"What seems clear is that there is no single 'memory molecule,'" concludes Scientific American. "Regardless of any competing candidate, PKMzeta needs a second molecule to maintain long-term memories, and there is another that can substitute in a pinch.""There are also some types of memory, such as the association of a location with fear, that do not depend on PKMzeta," the report adds. "Nobody knows what molecules are involved in those cases, and PKMzeta is clearly not the whole story."
The persistence of memory is crucial to our sense of identity, and without it, there would be no learning, for us or any other animal. It's little wonder, then, that some researchers have called how the brain stores memories the most fundamental question in neuroscience. A milestone in the effort to answer this question came in the early 1970s, with the discovery of a phenomenon called long-term potentiation, or LTP. Scientists found that electrically stimulating a synapse that connects two neurons causes a long-lasting increase in how well that connection transmits signals. Scientists say simply that the "synaptic strength" has increased. This is widely believed to be the process underlying memory. Networks of neural connections of varying strengths are thought to be what memories are made of.In the search for molecules that enable LTP, two main contenders emerged. One, called PKMzeta (protein kinase Mzeta), made a big splash when a 2006 study showed that blocking it erased memories for places in rats. If obstructing a molecule erases memories, researchers reasoned, that event must be essential to the process the brain uses to maintain memories. A flurry of research into the so-called memory molecule followed, and numerous experiments appeared to show that it was necessary and sufficient for maintaining numerous types of memory. The theory had a couple of holes, though. First, PKMzeta is short-lived. "Those proteins only last in synapses for a couple of hours, and in neurons, probably a couple of days," says Todd Sacktor, a neurologist at SUNY Downstate Health Sciences University, who was co-senior author of the 2006 study. "Yet our memories can last 90 years, so how do you explain this difference?" Second, PKMzeta is created in cells as needed, but then it has to find the right synapses. Each neuron has around 10,000 synapses, only a few percent of which are strengthened, says neuroscientist Andre Fenton, the other co-senior author of the 2006 study, who is now at New York University. The strengthening of some synapses and not others is how this mechanism stores information, but how PKMzeta molecules accomplish this was unknown.A new study published in Science Advances by Sacktor, Fenton and their colleagues plugs these holes. The research suggests that PKMzeta works alongside another molecule, called KIBRA (kidney and brain expressed adaptor protein), which attaches to synapses activated during learning, effectively "tagging" them. KIBRA couples with PKMzeta, which then keeps the tagged synapses strengthened. Experiments show that blocking the interaction between these two molecules abolishes LTP in neurons and disrupts spatial memories in mice. Both molecules are short-lived, but their interaction persists. "It's not PKMzeta that's required for maintaining a memory, it's the continual interaction between PKMzeta and this targeting molecule, called KIBRA," Sacktor says. "If you block KIBRA from PKMzeta, you'll erase a memory that's a month old." The specific molecules will have been replaced many times during that month, he adds. But, once established, the interaction maintains memories over the long term as individual molecules are continually replenished. [...]
World's First Zinc-Ion Battery Megafactory Opens For BusinessPosted by BeauHD on Wednesday September 04, 2024 @03:00AM from the safe-energy-solutions dept.Sweden's Enerpoly has opened the world's first zinc-ion battery megafactory near Stockholm, aiming for a 100 MWh annual capacity by 2026. "According to Enerpoly, this megafactory will serve Europe's needs for safe energy storage, and also utilize an all-European supply chain to boot," reports New Atlas. From the report:CitarIf you're wondering why Enerpoly is bothering with zinc-ion and not lithium-ion batteries, it's because the former is a better choice for storage in several ways:They use a water-based electrolyte, which makes them non-flammable, and reduces the risk of fires and explosions.They're less expensive, because zinc is far more abundant than lithium (which is difficult and expensive to extract), and easier to handle. They can also operate across a wider temperature range and require less maintenance, making them cheaper than lithium-ion options.They're more eco-friendly for the same reason. In contrast, extracting lithium currently requires extensive mining as well as the use of massive evaporation ponds before processing even begins.They're said to last a whole lot longer. According to the International Zinc Association, a nonprofit trade association which counts Enerpoly as a member, zinc-based batteries can last up to 20 years, while lithium batteries manage about 12 years.The downside? They have a lower energy density than something like a Tesla 4680 battery, making them ideal for applications like load shifting and grid resilience.
If you're wondering why Enerpoly is bothering with zinc-ion and not lithium-ion batteries, it's because the former is a better choice for storage in several ways:They use a water-based electrolyte, which makes them non-flammable, and reduces the risk of fires and explosions.They're less expensive, because zinc is far more abundant than lithium (which is difficult and expensive to extract), and easier to handle. They can also operate across a wider temperature range and require less maintenance, making them cheaper than lithium-ion options.They're more eco-friendly for the same reason. In contrast, extracting lithium currently requires extensive mining as well as the use of massive evaporation ponds before processing even begins.They're said to last a whole lot longer. According to the International Zinc Association, a nonprofit trade association which counts Enerpoly as a member, zinc-based batteries can last up to 20 years, while lithium batteries manage about 12 years.
FDA Grants Neuralink With Breakthrough Device Tag For 'Blindsight' ImplantPosted by BeauHD on Wednesday September 18, 2024 @03:00AM from the life-changing-tech dept.Neuralink said on Tuesday it has received the FDA's "breakthrough device" designation for its experimental implant aimed at restoring vision. Called Blindsight, the device "will enable even those who have lost both eyes and their optic nerve to see," said Neuralink founder Elon Musk. Reuters reports:CitarThe FDA's breakthrough tag is given to certain medical devices that provide treatment or diagnosis of life-threatening conditions. It is aimed at speeding up development and review of devices currently under development. Neuralink did not immediately respond to a request seeking details about when it expects the Blindsight device to move into human trials.
The FDA's breakthrough tag is given to certain medical devices that provide treatment or diagnosis of life-threatening conditions. It is aimed at speeding up development and review of devices currently under development. Neuralink did not immediately respond to a request seeking details about when it expects the Blindsight device to move into human trials.
Fly Brain Breakthrough 'Huge Leap' To Unlock Human MindPosted by BeauHD on Thursday October 03, 2024 @09:25PM from the technological-feats dept.fjo3 shares a report from the BBC:CitarThey can walk, hover and the males can even sing love songs to woo mates -- all this with a brain that's tinier than a pinhead. Now for the first time scientists researching the brain of a fly have identified the position, shape and connections of every single one of its 130,000 cells and 50 million connections. It's the most detailed analysis of the brain of an adult animal ever produced. One leading brain specialist independent of the new research described the breakthrough as a "huge leap" in our understanding of our own brains. One of the research leaders said it would shed new light into âoethe mechanism of thought." [...]The images the scientists have produced, which have been published in the journal Nature, show a tangle of wiring that is as beautiful as it is complex. Its shape and structure holds the key to explaining how such a tiny organ can carry out so many powerful computational tasks. Developing a computer the size of a poppy seed capable of all these tasks is way beyond the ability of modern science. Dr Mala Murthy, another of the projectâ(TM)s co-leaders, from Princeton University, said the new wiring diagram, known scientifically as a connectome, would be âoetransformative for neuroscientists." [...] The researchers have been able to identify separate circuits for many individual functions and show how they are connected. The wires involved with movement for example are at the base of the brain, whereas those for processing vision are towards the side. There are many more neurons involved in the latter because seeing requires much more computational power. While scientists already knew about the separate circuits they did not know how they were connected together.Anyone can view and download the fly connectome here.
They can walk, hover and the males can even sing love songs to woo mates -- all this with a brain that's tinier than a pinhead. Now for the first time scientists researching the brain of a fly have identified the position, shape and connections of every single one of its 130,000 cells and 50 million connections. It's the most detailed analysis of the brain of an adult animal ever produced. One leading brain specialist independent of the new research described the breakthrough as a "huge leap" in our understanding of our own brains. One of the research leaders said it would shed new light into âoethe mechanism of thought." [...]The images the scientists have produced, which have been published in the journal Nature, show a tangle of wiring that is as beautiful as it is complex. Its shape and structure holds the key to explaining how such a tiny organ can carry out so many powerful computational tasks. Developing a computer the size of a poppy seed capable of all these tasks is way beyond the ability of modern science. Dr Mala Murthy, another of the projectâ(TM)s co-leaders, from Princeton University, said the new wiring diagram, known scientifically as a connectome, would be âoetransformative for neuroscientists." [...] The researchers have been able to identify separate circuits for many individual functions and show how they are connected. The wires involved with movement for example are at the base of the brain, whereas those for processing vision are towards the side. There are many more neurons involved in the latter because seeing requires much more computational power. While scientists already knew about the separate circuits they did not know how they were connected together.
Cheetos Food Dye Turns Mice TransparentPosted by BeauHD on Friday October 04, 2024 @03:00AM from the puff-piece dept.Researchers have discovered that a popular food dye used in Cheetos "alters the optical qualities of skin, allowing light to pass through (Source paywalled; alternative source)," according to the Wall Street Journal. Larger doses of the dye used on humans could make searching veins for blood draw easier. From a report:CitarTartrazine, the yellowing agent for the "dangerously cheesy" snack, was tested on the stomachs and heads of mice -- with surprising results. Researchers were even able to see muscle pulsations and blood vessels in their brains, the Wall Street Journal reported.How does this ultimate magic trick work? It has to do with how cells are comprised of membranes that hold fats in a watery style, the outlet stated. The fats and water manage light differently. In this case, when the dye is applied, it causes light to pass through when it hits their cells. Thus, ta-da! the transparent opacity of invisible mice skin.The findings have been published in the journal Science.
Tartrazine, the yellowing agent for the "dangerously cheesy" snack, was tested on the stomachs and heads of mice -- with surprising results. Researchers were even able to see muscle pulsations and blood vessels in their brains, the Wall Street Journal reported.How does this ultimate magic trick work? It has to do with how cells are comprised of membranes that hold fats in a watery style, the outlet stated. The fats and water manage light differently. In this case, when the dye is applied, it causes light to pass through when it hits their cells. Thus, ta-da! the transparent opacity of invisible mice skin.
CitarAnyone can view and download the fly connectome here.Saludos.
Anyone can view and download the fly connectome here.
https://www.economist.com/leaders/2024/10/03/a-map-of-a-fruit-flys-brain-could-help-us-understand-our-ownhttps://www.economist.com/science-and-technology/2024/10/02/an-adult-fruit-fly-brain-has-been-mapped-human-brains-could-followSaludos.
Cita de: Cadavre Exquis en Octubre 06, 2024, 00:16:04 amhttps://www.economist.com/leaders/2024/10/03/a-map-of-a-fruit-flys-brain-could-help-us-understand-our-ownhttps://www.economist.com/science-and-technology/2024/10/02/an-adult-fruit-fly-brain-has-been-mapped-human-brains-could-followSaludos.Y ahora es cuando los periolistos sacan la conclusión que ahora que ya hay un mapa, se comprende por completo como funciona un cerebro y en un par de años ya tendremos lo mismo en humanos.Esto es sólo un paso. Ahora lo complicado viene por el lado de la extrema complejidad del mapa, que implica que computacionalmente no es tratable simular el funcionamiento de este cerebro, pese a lo que pudiese pensarse. Y eso es sólo para una mosca. Los animales mayores tienen una complejidad que se dispara por el número tan absolutamente gigantesco de neuronas que tienen (y por tanto exponencialmente más conexiones).Hay que tener en cuenta que cada neurona individual tiene un modelo físico extremadamente complejo y que no es conocido en su totalidad (tengamos en cuenta que hablamos de estructuras a escala molecular), que se ve a su vez influido por señales electroquímicas y físicas de todo tipo y en su mayoría poco conocidas, pero que se sospecha que tienen influencia en la computación que realizan. Eso implica que para simular y/o comprender este cerebro habría que hace una simulación a nivel molecular de los mecanismos de cada neurona, lo cual se escapa por completo de las capacidades actuales (al menos a tiempo real).Al contrario que un microprocesador, con partes muy concretas que se encargan de cada rol dentro de una computación (muy similar a una cadena de montaje) y que sólo realizan una instrucción de cada vez (más o menos, hoy día es más complejo, pero la idea original persiste), nuestros cerebros utilizan una computación hecha de billones de computaciones más pequeñas. Cada neurona es un pequeño procesador celular y la interacción entre todo ello es lo que produce el comportamiento. Es un paradigma totalmente diferente de lo que hacen los ordenadores, y totalmente diferente de lo que hacen las IA (los modelos de aprendizaje automático en uso hoy día).Nota para legos: las "redes neuronales" no tienen nada de parecido con una neurona real. El funcionamiento físico de una neurona real sólo es conocido a a grandes rasgos, y las mal llamadas neuronas matemáticas están basadas muy libremente en el funcionamiento teórico de una neurona real.No se sabe a qué nivel de detalle físico sería necesaria la emulación para poder reproducir fielmente el comportamiento de un insecto real, pero incluso a un nivel muy superficial ya sería todo un reto tecnológico.
Cita de: pollo en Octubre 06, 2024, 01:08:01 amCita de: Cadavre Exquis en Octubre 06, 2024, 00:16:04 amhttps://www.economist.com/leaders/2024/10/03/a-map-of-a-fruit-flys-brain-could-help-us-understand-our-ownhttps://www.economist.com/science-and-technology/2024/10/02/an-adult-fruit-fly-brain-has-been-mapped-human-brains-could-followSaludos.Y ahora es cuando los periolistos sacan la conclusión que ahora que ya hay un mapa, se comprende por completo como funciona un cerebro y en un par de años ya tendremos lo mismo en humanos.Esto es sólo un paso. Ahora lo complicado viene por el lado de la extrema complejidad del mapa, que implica que computacionalmente no es tratable simular el funcionamiento de este cerebro, pese a lo que pudiese pensarse. Y eso es sólo para una mosca. Los animales mayores tienen una complejidad que se dispara por el número tan absolutamente gigantesco de neuronas que tienen (y por tanto exponencialmente más conexiones).Hay que tener en cuenta que cada neurona individual tiene un modelo físico extremadamente complejo y que no es conocido en su totalidad (tengamos en cuenta que hablamos de estructuras a escala molecular), que se ve a su vez influido por señales electroquímicas y físicas de todo tipo y en su mayoría poco conocidas, pero que se sospecha que tienen influencia en la computación que realizan. Eso implica que para simular y/o comprender este cerebro habría que hace una simulación a nivel molecular de los mecanismos de cada neurona, lo cual se escapa por completo de las capacidades actuales (al menos a tiempo real).Al contrario que un microprocesador, con partes muy concretas que se encargan de cada rol dentro de una computación (muy similar a una cadena de montaje) y que sólo realizan una instrucción de cada vez (más o menos, hoy día es más complejo, pero la idea original persiste), nuestros cerebros utilizan una computación hecha de billones de computaciones más pequeñas. Cada neurona es un pequeño procesador celular y la interacción entre todo ello es lo que produce el comportamiento. Es un paradigma totalmente diferente de lo que hacen los ordenadores, y totalmente diferente de lo que hacen las IA (los modelos de aprendizaje automático en uso hoy día).Nota para legos: las "redes neuronales" no tienen nada de parecido con una neurona real. El funcionamiento físico de una neurona real sólo es conocido a a grandes rasgos, y las mal llamadas neuronas matemáticas están basadas muy libremente en el funcionamiento teórico de una neurona real.No se sabe a qué nivel de detalle físico sería necesaria la emulación para poder reproducir fielmente el comportamiento de un insecto real, pero incluso a un nivel muy superficial ya sería todo un reto tecnológico.Si a todo, pero el desafio no es computacional-Tampoco existian microscopios y se fueron fabricando,He corregido el link al pdfhttps://www.nature.com/articles/s41586-024-07686-5.pdfLos ordenadores ya permiten reproducir el cerebro virtual de la mosca, en 3 dimensiones-Pero el desafio no es la reproducción de la red biológica sino la tipificación o etiquetado de cada neurona (célula sinapsis y transmisores) para conseguir su clasificación funcional (vision, sensores, emisores, hacia el sistema orgánico) y los procedimientos que permitan discriminar y verificar que son realmente funcionalesNo están en la labor de saber qué hacen las neuronas- Están en la fase previa, la de clasificación, que llevará a una tabla de tipos-neuronales, como antes andaban buscando la tabla de elementos- Hacen investigación científica, no una una aplicación tecnológica del estado actual de una ciencia (eso es lo que hace o haría la IA -- una tecnologia crea un producto) Por ejemplo, explican las premisas experimentales sobre las que se pueden reducir 13,8 M de neuronas a 8500 tipos funcionales,Es esa reducción a tipos (como asignar elementos o pesos atómicos a la materia quimica) la que permite razonar sobre las redes neuronales, su funcionamiento y su similitud con cerebros de mamiferos, El paper que he citado explica cómo han ido identificando tipos y determinado experimentalmente que son constantes (no bolsas de cereales seleccionadas de forma arbitraria) es muy interesante- No requiere especiales conocimientos de biologia, y aunque haya que leer lentamente (yo al menos) el razonamiento es de un cientifico que busca una LeyDe hecho, ya enuncia dos de ellas, y explica como verificarlas, Pero la base de investigación por ahora sólo dispone de un sólo cerebro completo y otro medio cerebro de moscas, Esas leyes tendrán que probarse con cerebros más complejos (ratones)- Queda por desarrollar el sw para "diseccionar" los cerebros (con la información de los microscopios) Vale la pena leerlo- Es una muy buena lección de ciencia experimental,
https://www.eleconomista.es/tecnologia/noticias/13028509/10/24/elon-musk-desvela-los-tesla-cybercab-el-coche-autonomo-que-costara-27500-euros.htmlDotCSV Lab | ¡EVENTO TESLA en 10 MINUTOS! Anuncio del CYBERCAB en EspañolSaludos.
Impresionante quinto vuelo del Starship de SpaceX, captura de la primera etapa con los chopsticks de Mechazilla incluidaPor @Wicho — 13 de Octubre de 2024https://x.com/SpaceX/status/1845440879844261938Tras unas cuantas semanas de espera por la autorización de la Administración Federal de Aviación (FAA) de los Estados Unidos hoy por fin ha tenido lugar el quinto lanzamiento de un Starship de SpaceX. Falta por analizar los datos pero a priori todo indica que ha sido un gran éxito.La Starship S30 –la segunda etapa, que se llama como el cohete entero– amerizó de una pieza y con la precisión suficiente como para que la grabara una cámara cercana. Aunque es cierto que por momentos dio la impresión de que el plasma causado por la reentrada se iba a colar entre una de las aletas y el cuerpo del cohete, del mismo modo que el el cuarto lanzamiento. Y no está claro aún si la explosión de la S30 después del amerizaje estaba prevista para evitar dejar restos sobre la superficie del mar o si fue un RUD, un desmontaje rápido no programado.Pero, sobre todo, y esto ha sido absolutamente impresionante, el Booster B12, la primera etapa, volvió a base y fue capturada por los brazos mecánicos –chopsticks– de la torre de lanzamiento –Mechazilla–. Era la primera vez que SpaceX intentaba tal cosa y he de decir que para nada las tenía todas conmigo. Por mucho que SpaceX lleve años demostrando una enorme precisión en los aterrizajes de las primeras etapas de los Falcon 9.https://x.com/SpaceX/status/1845442658397049011Sí, es cierto que aún falta que Starship –la segunda etapa– entre en órbita, pues el de hoy era un vuelo suborbital; hay que ver cómo de intacto ha quedado el Booster 10 y si podrá ser utilizado de nuevo. Aunque lo más probable es que lo desmonten hasta el último tornillo para ver cómo lo ha afectado el vuelo y ver por qué había algo ardiendo en su parte inferior tras la captura, además de por qué se desprendieron trozos de esa misma parte en los últimos del vuelo.Y aún falta más para que Starship vuele con cargas útiles o que demuestre la transferencia de combustible entre dos Starship. Y mucho más aún para que lo haga con un sistema de soporte vital que le permita misiones tripuladas.Pero una vez más hemos visto en directo y en 4K como SpaceX escribía un nuevo capítulo en la historia de la exploración espacial.Otra buena noticia es que la autorización de la FAA para el lanzamiento de hoy incluye también la de futuros vuelos con el mismo perfil, así que dado que todo ha ido más o menos según lo previsto la fecha del sexto vuelo del Starship depende que de SpaceX esté lista, no de la FAA. Así que no me atrevo a decir que será en días, pero sí que en pocas semanas.