Monday, 23 June 2014

Lost slumber could mean perdidos neurons

A large portion of us wish we got more rest. Consistently, something whether its kids, work or the Internet appears to keep us up late. Off and on again it keeps us up throughout the night. Frequently we comfort ourselves with the prospect that when in doubt, we can make it up with a couple of robust nights of mull over the weekend.

Yet new research demonstrates that the mind may not be as excusing as we trusted. While a couple of additional hours on the Internet may be vindicated, dusk 'til dawn affairs like those connected with movement work may wind up killing off neurons.

There is no doubt that rest is critical. It cleans our cerebrum cells and aides merge our memories. Absence of slumber blunts our capability to center, makes us risky drivers and can make us consume excessively. Jing Zhang and her associates at the University of Pennsylvania Perelman School of Medicine in Philadelphia were intrigued by the impacts of slumber misfortune on the cerebrum. "A hefty portion of us have pulled long nights and/or dusk 'til dawn affairs, and we think we're OK," says Sigrid Veasey, a neurobiologist at Penn and coauthor on the study. "Yet what is the impact? Is there a compensatory component? Then again does the cerebrum pay a cost for rehashed slumber misfortune?" 

The scientists were especially intrigued by the locus ceruleus, a territory of neurons profound in the mind stem. The locus ceruleus assumes an imperative part in consideration, "battle or flight" and our slumber wake cycles. Yet the locus ceruleus is additionally exceptionally touchy to stretch. Furthermore late nights can make those cells exceptionally fatigued without a doubt.

To look at how the mind may react to diminished slumber, Zhang and associates place mice in new, fascinating situations with other mice to play with and a lot of things to investigate. With this mouse play area, the analysts could keep the creatures up far past their bedtimes. The researchers took a gander at mice with typical slumber plans, mice that stayed up three hours after the fact than ordinary and mice with a night-movement plan kept astir throughout the day for three days in a row. In all cases, the mice could get to the extent that as they needed throughout the night, their typical dynamic period.

In a paper published march 19 in the journal of Neuroscience, Zhang and her gathering indicated that three hours of lost rest in the mouse play area delivered a build in Sirtuin3, or Sirt3, a protein in a phone's mitochondria. Sirt3 has a ton of capacities, and one of them is diminishing chemicals called responsive oxygen species. These atoms are equipped for tying to and upsetting various kinds of cell methodologies. ROS are a common by-result of a cell's every day life, however an excess of gathering in the phone can get hazardous as the particles tie to typical proteins, bringing about harm and inevitably cell demise.

By expanding Sirt3 protein when mice stay up late, the cerebrum cells in the locus ceruleus are primed to manage the ROS. In any case when the mice celebrated throughout the night, the circumstances switched. Sirt3rna levels went down, while ROS levels kept on increaing. With three days of eight-hour lack of sleep, the neurons in the locus ceruleus really started to kick the bucket. Resting didn't make up for the slumber lost.

Sirt3 has all the earmarks of being a key protein for ensuring neurons from harm from ROS particles throughout late nights. In mice failing to offer the gene for the Sirt3 protein, even three hours of lack of sleep brought about neuron harm from ROS.

"We didn't think the cerebrum got harmed from slumber misfortune," Veasey says. "Presently we know it does." She clarifies that the following step will be to check whether there is comparative harm in people who have done a lot of movement work, maybe by inspecting after death brains. Veasey additionally plans to check whether expanding Sirt3 can secure against the impacts of dusk 'til dawn affairs.

While it is fascinating to see another part for Sirt3 in slumber, Matthew Hirschey, a cell researcher at Duke University, says that its not so much astounding. "Sirt3 is a mitochondrial protein, he says, "and mitochondrial capacity touches such a large amount of science." furthermore, on the grounds that each cell in the body has Sirt3 in its mitochondria, expanding Sirt3 may have a bigger number of impacts than ensuring your neurons from a late night. "By and large," Hirschey says, "it gives off an impression of being a decent thing, however some disease cells have high Sirt3 also."

It will additionally be critical to check whether the locus ceruleus can recoup from neuron misfortune, and in the event that it even matters. Zhang's gathering did not run behavioral studies to check whether the sleepless mice had shortages in consideration or memory, or if these turned around with recuperation rest. They additionally don't know whether neuron misfortune proceeds over long haul movement work, or if the cerebrum can alter. Yet Veasey says the current discoveries are terrifying enough: "Every one of us in the lab consider rest a great deal more important than we us.

Tuesday, 12 February 2013

Neuronios Perdidos - Plasticidade

O nosso cérebro vai mudando constantemente ao longo das nossas vidas. Esta característica do cérebro é conhecida como plasticidade – em analogia aos modelos de plasticina que podem ser constantemente moldados e mudar de forma. Apesar do cérebro como um todo ser elativamente imutável, os neurónios individuais podem ser modificados por diferentes.

razões – durante o desenvolvimento enquanto são jovens, em resposta a agressão cerebral, e durante aprendizagem. Existem vários mecanismos de plasticidade, sendo a plasticidade
sináptica o mais importante – esta área de estudo procura perceber como é que os neurónios alteram a sua capacidade para comunicar entre si.

Tuesday, 14 August 2012


O neurónio (português europeu) ou neurônio (português brasileiro) é a célula do sistema nervoso responsável pela condução do impulso nervoso. Há cerca de 86 bilhões (até 20 de fevereiro de 2009 se especulava que havia 100 bilhões) de neurônios no sistema nervoso humano. O neurônio é constituído pelas seguintes partes: corpo celular, o núcleo celular, dendritos (prolongamentos numerosos e curtos do corpo celular, receptores de mensagens), axônio (prolongamento que transmite o impulso nervoso vindo do corpo celular) e telodendritos.

O neurônio pode ser considerado a unidade básica da estrutura do cérebro e do sistema nervoso. A membrana exterior de um neurônio toma a forma de vários ramos extensos chamados dendritos, que recebem sinais elétricos de outros neurônios, e de uma estrutura a que se chama um axônio que envia sinais elétricos a outros neurônios. O espaço entre o dendrito de um neurônio e os telodendritos de outro é o que se chama uma fenda sináptica: os sinais são transportados através das sinapses por uma variedade de substâncias químicas chamadas neurotransmissores. O córtex cerebral é um tecido fino composto essencialmente por uma rede de neurônios densamente interligados tal que nenhum neurônio está a mais do que algumas sinapses de distância de qualquer outro neurônio.

Os neurônios recebem continuamente impulsos nas sinapses de seus dendritos vindos de milhares de outras células. Os impulsos geram ondas de corrente elétrica (excitatória ou inibitória, cada uma num sentido diferente) através do corpo da célula até a uma zona chamada a zona de disparo, no começo do axônio. É aí que as correntes atravessam a membrana celular para o espaço extracelular e que a diferença de voltagem que se forma na membrana determina se o neurônio dispara ou não.

Esquema de um neurônio.
Os neurônios caracterizam-se pelos processos que conduzem impulsos nervosos para o corpo e do corpo para a célula nervosa. Os impulsos nervosos são reações físico-químicas que se verificam nas superfícies dos neurônios e seus processos. Reações semelhantes ocorrem em muitos outros tipos de células mas elas são mais notáveis nos neurônios, cujos caracteres estruturais se destinam a facilitar a transmissão dos impulsos a grandes distâncias. A cromatina nuclear é escassa, enquanto que o nucléolo é muito proeminente. O DNA está presente na cromatina sexual, que é maior em neurônios de indivíduos do sexo feminino. A substância cromidial no citoplasma é chamada de substância de Nissl. À microscopia eletrônica mostra-se disposta em tubos estreitos recobertos de finos grânulos. Estudos histoquímicos e outros demostraram-na constituída de nucleoproteínas. Estas nucleoproteínas diminuem durante a atividade celular intensa e durante a cromatólise que se segue à secção de axônios.

Wednesday, 13 July 2011

Network monitoring

While an intrusion detection system monitors a network for threats from the outside, a network monitoring system monitors the network for problems caused by overloaded and/or crashed servers, network connections or other devices.

For example, to determine the status of a webserver, monitoring software may periodically send an HTTP request to fetch a page. For email servers, a test message might be sent through SMTP and retrieved by IMAP or POP3.

Commonly measured metrics are response time, availability and uptime, although both consistency and reliability metrics are starting to gain popularity. The widespread addition of WAN optimization devices is having an adverse effect on most network monitoring tools -- especially when it comes to measuring accurate end-to-end response time because they limit round trip visibility.