In vitro characterisation of cell-level neurophysiological diversity in the rostral nucleus reuniens of adult mice

PublishedThis is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.The nucleus reuniens (Re) is the largest of the midline thalamic nuclei. We have performed a detailed neurophysiological characterization of neurons in the rostral Re of brain slices prepared from adult male mice. At resting potential (−63.7 ± 0.6 mV), circa 90% of Re neurons fired action potentials, typically continuously at ∼8 Hz. Although Re neurons experience a significant spontaneous barrage of fast, amino-acid-mediate synaptic transmission, this was not predominantly responsible for spontaneous spiking as firing persisted in the presence of glutamate and GABA receptor antagonists. With resting potential preset to −80 mV −20 pA current injections revealed a mean input resistance of 615 MΩ and mean time constant of 38 ms. Following cessation of this stimulus a significant rebound potential was seen that was sometimes large enough to trigger a short burst of very high frequency (100–300 Hz) firing. In most cells short (2 ms), strong (2 nA) current injections elicited a single spike followed by a large afterdepolarizing potential (ADP) which, when suprathreshold, generated high frequency spiking. Similarly, in the majority of cells preset at −80 mV, 500 ms depolarizing current injections to cells led to a brief initial burst of very high frequency firing, although this was lost when cells were preset at −72 mV. Biophysical and pharmacological experiments indicate a prominent role for T-type Ca2+ channels in the high-frequency bursting of Re neurons. Finally, we describe a novel form of activity-dependent intrinsic plasticity that persistently eliminates the burst firing potential of Re neurons

A Lagrangian vertical coordinate version of the ENDGame dynamical core. Part I: Formulation, remapping strategies, and robustness

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Previous work provides evidence that Lagrangian conservation and related properties of a numerical model dynamical core can be improved by the use of a Lagrangian or quasi-Lagrangian vertical coordinate (LVC). Most previous model developments based on this idea have made the hydrostatic approximation. Here the LVC is implemented in a nonhydrostatic compressible Euler equation dynamical core using almost identical numerical methods to ENDGame, the operational dynamical core of the Met Office atmospheric Unified Model. This enables a clean comparison of LVCand height-coordinate versions of the dynamical core using numerical methods that are as similar as possible. Since Lagrangian surfaces distort over time, model level heights are continually reset to certain ‘target levels’ and the values of model fields are remapped onto their new locations. Different choices for these target levels are discussed, along with remapping strategies that focus on different conservation or balance properties. Sample results from a baroclinic instability test case are presented. The LVC formulation is found to be rather less robust than the height-coordinate version; some reasons for this are discussed.We are grateful to Nigel Wood for pointing out the computational mode of the LVC vertical discretization. We also thank two anonymous reviewers for their constructive comments on an earlier version of this paper. This work was funded by the Natural Environment Research Council under grant NE/H006834/1

Collapsing Perfect Fluid in Higher Dimensional Spherical Spacetimes

The general metric for N-dimensional spherically symmetric and conformally flat spacetimes is given, and all the homogeneous and isotropic solutions for a perfect fluid with the equation of state $p = \alpha \rho$ are found. These solutions are then used to model the gravitational collapse of a compact ball. It is found that when the collapse has continuous self-similarity, the formation of black holes always starts with zero mass, and when the collapse has no such a symmetry, the formation of black holes always starts with a mass gap.Comment: Class. Quantum Grav. 17 (2000) 2589-259

Surface-Atmosphere Coupling Scale, the Fate of Water, and Ecophysiological Function in a Brazilian Forest

This is the final verison. Available from American Geophysical Union (AGU) via the DOI in this record.The K83 observational data are available from AmeriFlux (ameriflux.lbl.gov), NCEP Reanalysis data provided by NOAA/ESRL/PSD, Boulder, Colorado, USA, from the http://www.cdc.noaa.gov/ website. Model code and output is stored at GitLab (gitlab.com). This project is password protected, and the password can be obtained from the corresponding author at [email protected] upon request.Tropical South America plays a central role in global climate. Bowen ratio teleconnects to circulation and precipitation processes far afield, and the global CO2 growth rate is strongly influenced by carbon cycle processes in South America. However, quantification of basin-wide seasonality of flux partitioning between latent and sensible heat, the response to anomalies around climatic norms, and understanding of the processes and mechanisms that control the carbon cycle remains elusive. Here, we investigate simulated surface-atmosphere interaction at a single site in Brazil, using models with different representations of precipitation and cloud processes, as well as differences in scale of coupling between the surface and atmosphere. We find that the model with parameterized clouds/precipitation has a tendency toward unrealistic perpetual light precipitation, while models with explicit treatment of clouds produce more intense and less frequent rain. Models that couple the surface to the atmosphere on the scale of kilometers, as opposed to tens or hundreds of kilometers, produce even more realistic distributions of rainfall. Rainfall intensity has direct consequences for the “fate of water,” or the pathway that a hydrometeor follows once it interacts with the surface. We find that the model with explicit treatment of cloud processes, coupled to the surface at small scales, is the most realistic when compared to observations. These results have implications for simulations of global climate, as the use of models with explicit (as opposed to parameterized) cloud representations becomes more widespread.National Aeronautics and Space Administration (NASA)National Science Foundation (NSF)National Science Foundation (NSF)U.S. Department of Energy (DOE

On massless 4D Gravitons from 5D Asymptotically AdS Space-times

We investigate the conditions for obtaining four-dimensional massless spin-2 states in the spectrum of fluctuations around an asymptotically $AdS_5$ solution of Einstein-Dilaton gravity. We find it is only possible to have normalizable massless spin-2 modes if the space-time terminates at some IR point in the extra dimension, far from the UV AdS boundary, and if suitable boundary conditions are imposed at the ``end of space.'' In some of these cases the 4D spectrum consists only of a massless spin-2 graviton, with no additional massless or light scalar or vector modes. These spin-2 modes have a profile wave-function peaked in the interior of the 5D bulk space-time. Under the holographic duality, they may be sometimes interpreted as arising purely from the IR dynamics of a strongly coupled QFT living on the AdS boundary.Comment: 40 pages, 1 figure. Revised version, to appear in Nuclear Physics B. Typos corrected, one reference adde

The fifth dimension as an analogue computer for strong interactions at the LHC

We present a mechanism to get S ~ 0 or even negative, without bringing into play the SM fermion sector. This mechanism can be applied to a wide range of 5D models, including composite Higgs and Higgsless models. As a realization of the mechanism we introduce a simple model, although the effect on S does not rely on the underlying dynamics generating the background. Models that include this mechanism enjoy the following features: weakly-coupled light resonances (as light as 600 GeV) and degenerate or inverted resonance spectrum.Comment: JHEP version. References adde

Neurophysiological alterations in the nucleus reuniens of a mouse model of Alzheimer's disease.

This is the author accepted manuscriptRecently, increased neuronal activity in nucleus reuniens (Re) has been linked to hyperexcitability within hippocampal-thalamo-cortical networks in the J20 mouse model of amyloidopathy. Here in vitro whole-cell patch clamp recordings were used to compare old pathology-bearing J20 mice and wild-type controls to examine whether altered intrinsic electrophysiological properties could contribute to the amyloidopathy-associated Re hyperactivity. A greater proportion of Re neurons display hyperpolarized membrane potentials in J20 mice without changes to the incidence or frequency of spontaneous action potentials. Re neurons recorded from J20 mice did not exhibit increased action potential generation in response to depolarizing current stimuli but an increased propensity to rebound burst following hyperpolarizing current stimuli. Increased rebound firing did not appear to result from alterations to T-type Ca2+ channels. Finally, in J20 mice, there was an ~8% reduction in spike width, similar to what has been reported in CA1 pyramidal neurons from multiple amyloidopathy mice. We conclude that alterations to the intrinsic properties of Re neurons may contribute to hippocampal-thalmo-cortical hyperexcitability observed under pathological beta-amyloid load.Alzheimer´s Research UKEli Lilly and Company Limited (T/A Lilly

Atmospheric Properties from the 2006 Niamey Deployment and Climate Simulation with a Geodesic Grid Coupled Climate Model Third Quarter 2008

In 2008, the Atmospheric Radiation Measurement (ARM) Program and the Climate Change Prediction Program (CCPP) have been asked to produce joint science metrics. For CCPP, the metrics will deal with a decade-long control simulation using geodesic grid-coupled climate model. For ARM, the metrics will deal with observations associated with the 2006 deployment of the ARM Mobile Facility (AMF) to Niamey, Niger. Specifically, ARM has been asked to deliver data products for Niamey that describe cloud, aerosol, and dust properties. This report describes the aerosol optical depth (AOD) product

Atmospheric Properties from the 2006 Niamey Deployment and Climate Simulation with a Geodesic Grid Coupled Climate Model Fourth Quarter 2008

In 2008, the Atmospheric Radiation Measurement (ARM) Program and the Climate Change Prediction Program (CCPP) have been asked to produce joint science metrics. For CCPP, the metrics will deal with a decade-long control simulation using geodesic grid-coupled climate model. For ARM, the metrics will deal with observations associated with the 2006 deployment of the ARM Mobile Facility (AMF) to Niamey, Niger. Specifically, ARM has been asked to deliver data products for Niamey that describe cloud, aerosol, and dust properties. The first quarter milestone was the initial formulation of the algorithm for retrieval of these properties. The second quarter milestone included the time series of ARM-retrieved cloud properties and a year-long CCPP control simulation. The third quarter milestone included the time series of ARM-retrieved aerosol optical depth and a three-year CCPP control simulation. This final fourth quarter milestone includes the time-series of aerosol and dust properties and a decade-long CCPP control simulation

Non-Z2\mathbb{Z}_{2} symmetric braneworlds in scalar tensorial gravity

We obtain, via the Gauss-Codazzi formalism, the expression of the effective Einstein-Brans-Dicke projected equations in a non-$\mathbb{Z}_{2}$ symmetric braneworld scenario which presents hybrid compactification. It is shown that the functional form of such equations resembles the one in the Einstein's case, except by the fact that they bring extra informations in the context of exotic compactifications.Comment: 12 pages, LATEX file, no figures. Accepted for publication in the European Physical Journal