Search results for "SYNOP"

Sharpness of the extratropical tropopause in baroclinic life cycle experiments

2007

[1] The sharpness of the extratropical tropopause is investigated using baroclinic life cycle experiments. In these simulations, slow synoptic scale dynamics leads to a net tropopause sharpening. The mechanism involves vertical convergence of the ageostrophic wind. The results support earlier suggestions from idealized theoretical studies.

Immune activation promotes evolutionary conservation of T-cell epitopes in HIV-1.

2013

The immune system should constitute a strong selective pressure promoting viral genetic diversity and evolution. However, HIV shows lower sequence variability at T-cell epitopes than elsewhere in the genome, in contrast with other human RNA viruses. Here, we propose that epitope conservation is a consequence of the particular interactions established between HIV and the immune system. On one hand, epitope recognition triggers an anti-HIV response mediated by cytotoxic T-lymphocytes (CTLs), but on the other hand, activation of CD4(+) helper T lymphocytes (TH cells) promotes HIV replication. Mathematical modeling of these opposite selective forces revealed that selection at the intrapatient l…

Marcion and the Dating of the Synoptic Gospels.By Markus Vinzent

2015

Dust mobilization and transport in the northern Sahara during SAMUM 2006 – a meteorological overview

2009

The SAMUM field campaign in southern Morocco in May/June 2006 provides valuable data to study the emission, and the horizontal and vertical transports of mineral dust in the Northern Sahara. Radiosonde and lidar observations show differential advection of air masses with different characteristics during stable nighttime conditions and up to 5-km deep vertical mixing in the strongly convective boundary layer during the day. Lagrangian and synoptic analyses of selected dust periods point to a topographic channel from western Tunisia to central Algeria as a dust source region. Significant emission events are related to cold surges from the Mediterranean in association with eastward passing upp…

Oligodendrocyte precursor cells modulate the neuronal network by activity-dependent ectodomain cleavage of glial NG2.

2014

The role of glia in modulating neuronal network activity is an important question. Oligodendrocyte precursor cells (OPC) characteristically express the transmembrane proteoglycan nerve-glia antigen 2 (NG2) and are unique glial cells receiving synaptic input from neurons. The development of NG2+ OPC into myelinating oligodendrocytes has been well studied, yet the retention of a large population of synapse-bearing OPC in the adult brain poses the question as to additional functional roles of OPC in the neuronal network. Here we report that activity-dependent processing of NG2 by OPC-expressed secretases functionally regulates the neuronal network. NG2 cleavage by the α-secretase ADAM10 yields…

Climate of the Mediterranean

2012

This chapter considers a set of issues related to the synoptic climatology of the Mediterranean region (MR). The main Northern Hemisphere teleconnections affecting the MR and their role on temperature, precipitation, and atmospheric cyclones are described. The characteristics of the cyclones in the MR are presented. The role of teleconnections and atmospheric regimes on temperature and precipitation is discussed. The content includes extremes of temperature, precipitation, wind, and storminess (considering also marine aspects such as waves and storm surges).

Lateral diffusion estimation in fully depleted thick CCD using flat field image analysis

2011

Abstract In thick fully depleted CCDs charge carrier transport from the back window to the gates is accompanied by charge diffusion. Lateral diffusion smooths out density variations of the incoming photon flux by redistributing charges spatially. This creates short range positive correlations in recorded amplitudes. Pixel-to-pixel amplitude variations can also be caused by pixel size and quantum efficiency variations. Pixel size variations result in short range negative correlations. Our study shows that the characteristic diffusion width can be extracted from flat field data. The study was performed on fully depleted, thick CCDs produced in a technology study for the Large Synoptic Survey …

Heat in Normandy, types of atmospheric circulation and climate change (1970 - 2019)

2020

Heat in Normandy, synoptic circulation patterns and climate change (1970-2019). This article focuses on the role and the evolution of the different kinds of synoptic circulation patterns in the occurrence of hot days in Normandy. Heat is here, very dependent on the presence of action centres over central Europe as well as, air flow coming from NE and E. Contemporary climate change expresses itself by a rise in thermal efficiency of all synoptic circulation patterns (more heat for the same flow). Lastly, the north of Cotentin stands out by being a real “cool island” during summer because of its peninsula position which imposes on any air mass, regardless of its origin, a cooling from its bot…