לוח שנה משולב

Genome-scale predictions of how microbes control their metabolic activity are rapidly improving in accuracy, largely owing to the development of mathematical models, which combine genomic and biochemical knowledge with efficient optimization algorithms.
Yet, some of the most fundamental properties of real microbial ecosystems crucially depend on aspects that are beyond the metabolic networks of individual species, such as metabolite-mediated interactions between different microbes and spatio-temporal variation of environmental conditions. Can current models account for such effects, and help understand the dynamics and evolution of complex microbial communities? We explore possible answers to this question, with applications ranging from "synthetic ecology" to the organization of the human microbiome.

I have almost 40 years of perspective on the climate change field, having entered the field in the early 1970s when it was in its infancy. I will discuss the recent ClimateGate stolen-emails brouhaha and the extent to which it has damaged the IPCC process of assessing future climate change. In 10-20 years, when climate change is more readily evident to the average resident of the planet, due mostly, perhaps, to its effects on living things, ClimateGate may be looked back on as somewhat of a "tempest in a teapot". However, it sounded a cautionary note about several areas of ignorance that had been somewhat swept under the rug in the rush to seem more certain about our climate future. Chief among those areas of ignorance, was the fact that we don't know the fate of half of the extra energy being put into the Earth system by rising CO2, and thus we can't explain why the global average temperature has leveled off in the past 10 years and actually seems to be declining slightly since 2005.

What we do know for certain, but are reluctant to expose publicly, is that our climate models are woefully inadequate to their intended task of predicting the future. For example, they predict too much warming, they missed the rapid decline in Arctic sea ice and the accelerating rise of sea level, they entirely miss "dimming and brightening" of surface solar radiation, and they can't begin to explain the past extremely cold, snowy winter in Europe and the U.S. They predicted that most of the warming would occur at night and in the winter, which might soften the blow somewhat, and that hasn't come true either. The limitations of models are now becoming more obvious, and it is becoming clear that we are barely beginning to be able to model Earth's climate on a regional basis.

TBA

We consider the fate of AdS vacua connected by tunneling events. A precise holographic dual of thin-walled Coleman--de Luccia bounces is proposed in terms of Fubini instantons in an unstable CFT. This proposal is backed by several qualitative and quantitative checks, including the precise calculation of the instanton action appearing in evaluating the decay rate. Big crunches manifest themselves as time dependent processes which reach the boundary of field space in a finite time. The infinite energy difference involved is identified on the boundary and highlights the ill-defined nature of the bulk setup. We propose a qualitative scenario in which the crunch is resolved by
stabilizing the CFT, so that all attempts at crunching always end up shielded from the boundary by the formation of black hole horizons. In all these well defined bulk processes the configurations have the same asymptotics and are finite energy excitations.

Synopsis: Depending on its severity and context, stress can affect neural plasticity. Most related studies focused on synaptic plasticity and long-term potentiation (LTP) of principle cells. However, evidence suggests that following stress, modifications can also take place at the level of complex interactions with interneurons, i.e. at the local circuit level. We set out to examine in vivo in the rat the possible impact of re-exposure to the context of a traumatic experience on the plasticity of the principle cells and on local circuit activity within the dentate gyrus (DG). Findings indicate that the re-exposure to a reminder of a traumatic experience affects not only aspects of synaptic plasticity of principle cells, but also aspects of local circuit activity. These alterations may underlie some of the behavioral consequences of the traumatic experience.