Moment tensor inversions of icequakes on Gornergletscher, Switzerland

We have determined seismic source mechanisms for shallow and intermediate-depth icequake clusters recorded on the glacier Gornergletscher, Switzerland, during the summers of 2004 and 2006. The selected seismic events are part of a large data set of over 80,000 seismic events acquired with a dense seismic network deployed in order to study the yearly rapid drainage of Gornersee lake, a nearby ice-marginal lake. Using simple frequency and distance scaling and Green’s functions for a homogeneous half-space, we calculated moment tensor solutions for icequakes with M_w-1.5 using a full-waveform inversion method usually applied to moderate seismic events (M_w>4) recorded at local to regional distances (≈50–700 km). Inversions from typical shallow events are shown to represent tensile crack openings. This explains well the dominating Rayleigh waves and compressive first motions observed at all recording seismograms. As these characteristics can be observed in most icequake signals, we believe that the vast majority of icequakes recorded in the 2 yr is due to tensile faulting, most likely caused by surface crevasse openings. We also identified a shallow cluster with somewhat atypical waveforms in that they show less dominant Rayleigh waves and quadrantal radiation patterns of first motions. Their moment tensors are dominated by a large double-couple component, which is strong evidence for shear faulting. Although less than a dozen such icequakes have been identified, this is a substantial result as it shows that shear faulting in glacier ice is generally possible even in the absence of extreme flow changes such as during glacier surges. A third source of icequakes was located at 100 m depth. These sources can be represented by tensile crack openings. Because of the high-hydrostatic pressure within the ice at these depths, these events are most likely related to the presence of water lenses that reduce the effective stress to allow for tensile faulting

The role of the catecholaminergic projections to the forebrain in the modulation of autonomic responses to stress

Exposure of animals to noxious or stressful stimuli increases heart rate (HR) and blood pressure through activation of the autonomic nervous system (ANS). Stressors also elicit the release of the neuromodulatory catecholamines dopamine (DA) and noradrenaline (NA) in several regions of the forebrain. Although many of these regions project to brainstem nuclei involved in the control of autonomic output, the functions of the catecholamines in the modulation of responses to stressful stimuli mediated by the ANS are not known. To resolve this issue, a series of experiments was carried out to examine the effects of injections of agonists, and antagonists of DAergic and NAergic receptors into four regions of the forebrain innervated by the catecholaminergic projections, on an autonomically-mediated response to stress, the increase in HR induced by tail pinch, in rats anesthetized with urethane. The regions tested included the medial frontal cortex (MFC), agranular insular cortex (AIC), nucleus accumbens (NAC) and the central nucleus of the amygdala (CeA). Injections of an antagonist of Ý-adrenoceptors into each of these regions reduced the magnitude of the increase in HR induced by tail pinch. Injections of an agonist of Ý-adrenoceptors in the MFC, AIC and NAC increased basal HR but did not affect the pinch response. Injections of drugs acting at Ì-adrenoceptors altered neither of these parameters, but injections of a combination of agonists of Ì- and Ý-adrenoceptors made into the NAC markedly increased the magnitude of the response to pinch. When injected alone, agonists or antagonists of DAergic receptors were largely without effect on basal HR and the response to pinch. However, injections of a combination of a D 2 antagonist and an agonist of the Ý-adrenoceptor into the AIC significantly increased the magnitude of the pinch response. These results provide the first clear evidence that catecholamines released in the forebrain during basal conditions and in response to stress are important modulators of autonomic output. NA, primarily through actions on Ý-adrenoceptors, exerts the most salient influence, serving to facilitate the output of the ANS during both of these conditions. In the case of the NAC, this NAergic influence may be facilitated, in turn, by the stimulation of Ì-adrenoceptors. Although DA in these regions may not have a salient influence on autonomic output, it may, via the stimulation of D 2 receptors, modulate the actions of NA on Ý-adrenoceptors in at least the AIC

Glycol-Based Lube Oil Behavior & Its Effects In Fuel Gas Compression System

Case StudiesOil-flooded screw compressors (2 units x 100% duty) deliver fuel gas from AGRU Absorber at saturated condition to GTG to sustain oil production facilities @ ~33 MW power demand. Each Fuel Gas Compressor (FGC) is rated for 0.788 Msm3/day with max 100 ppm H2

Chronic ethanol exposure increases microtubule content in PC12 cells

BACKGROUND: Chronic ethanol exposure has been shown to result in changes in neuronal cyto-architecture such as aberrant sprouting and alteration of neurite outgrowth. In PC12 cells, chronic ethanol treatment produces an increase in Nerve Growth Factor (NGF)-induced neurite outgrowth that appears to require the epsilon, but not delta, isoform of Protein Kinase C (PKC). Neurites contain a core of microtubules that are formed from polymerization of free-tubulin. Therefore, it would be expected that an increase in neurite outgrowth would correlate with an increase in microtubule content. We examined the effect of chronic ethanol exposure on microtubule content in PC12 cells and the role of PKC epsilon and delta in ethanol's effect on microtubule levels. RESULTS: Chronic ethanol exposure of wild-type and vector control PC12 cells resulted in a significant increase in microtubule content and a corresponding decrease in free tubulin. There was also a significant increase in microtubule content in PC12 cells expressing a dominate-negative inhibitor of epsilon PKC; cells which have previously been shown to have no ethanol-induced increase in neurite outgrowth. In contrast, ethanol had no effect on microtubule content in PC12 cells expressing a dominate-negative inhibitor of delta PKC. CONCLUSION: These results suggest that chronic ethanol exposure alters the relative ratio of free tubulin to microtubule-associated tubulin, an important component of the cytoskeleton. Further, the data from the PKC dominant-negative cell lines suggest that the effects of ethanol on microtubule content do not correlate with the effects of ethanol on neurite outgrowth. The delta isoform of PKC appears to be necessary for the ethanol-induced increase in microtubule content. These studies demonstrate an effect of chronic ethanol exposure which may contribute to previously documented alterations of neuronal cyto-architecture

Development of data acquisition and control facilities for the optimization of drive line efficiency

Call number: LD2668 .T4 1986 F86Master of ScienceMechanical and Nuclear Engineerin

The Evolution of Light Stress Proteins in Photosynthetic Organisms

The Elip (early light-inducible protein) family in pro- and eukaryotic photosynthetic organisms consists of more than 100 different stress proteins. These proteins accumulate in photosynthetic membranes in response to light stress and have photoprotective functions. At the amino acid level, members of the Elip family are closely related to light-harvesting chlorophyll a/b-binding (Cab) antenna proteins of photosystem I and II, present in higher plants and some algae. Based on their predicted secondary structure, members of the Elip family are divided into three groups: (a) one-helix Hlips (high light-induced proteins), also called Scps (small Cab-like proteins) or Ohps (one-helix proteins); (b) two-helix Seps (stress-enhanced proteins); and (c) three-helix Elips and related proteins. Despite having different physiological functions it is believed that eukaryotic three-helix Cab proteins evolved from the prokaryotic Hlips through a series of duplications and fusions. In this review we analyse the occurrence of Elip family members in various photosynthetic prokaryotic and eukaryotic organisms and discuss their evolutionary relationship with Cab proteins

Stress-Induced Reinstatement of Drug Seeking: 20 Years of Progress

In human addicts, drug relapse and craving are often provoked by stress. Since 1995, this clinical scenario has been studied using a rat model of stress-induced reinstatement of drug seeking. Here, we first discuss the generality of stress-induced reinstatement to different drugs of abuse, different stressors, and different behavioral procedures. We also discuss neuropharmacological mechanisms, and brain areas and circuits controlling stress-induced reinstatement of drug seeking. We conclude by discussing results from translational human laboratory studies and clinical trials that were inspired by results from rat studies on stress-induced reinstatement. Our main conclusions are (1) The phenomenon of stress-induced reinstatement, first shown with an intermittent footshock stressor in rats trained to self-administer heroin, generalizes to other abused drugs, including cocaine, methamphetamine, nicotine, and alcohol, and is also observed in the conditioned place preference model in rats and mice. This phenomenon, however, is stressor specific and not all stressors induce reinstatement of drug seeking. (2) Neuropharmacological studies indicate the involvement of corticotropin-releasing factor (CRF), noradrenaline, dopamine, glutamate, kappa/dynorphin, and several other peptide and neurotransmitter systems in stress-induced reinstatement. Neuropharmacology and circuitry studies indicate the involvement of CRF and noradrenaline transmission in bed nucleus of stria terminalis and central amygdala, and dopamine, CRF, kappa/dynorphin, and glutamate transmission in other components of the mesocorticolimbic dopamine system (ventral tegmental area, medial prefrontal cortex, orbitofrontal cortex, and nucleus accumbens). (3) Translational human laboratory studies and a recent clinical trial study show the efficacy of alpha-2 adrenoceptor agonists in decreasing stress-induced drug craving and stress-induced initial heroin lapse

Glycol-Based Lube Oil Behavior & Its Effects In Fuel Gas Compression System

Case StudiesOil-flooded screw compressors (2 units x 100% duty) deliver fuel gas from AGRU Absorber at saturated condition to GTG to sustain oil production facilities @ ~33 MW power demand. Each Fuel Gas Compressor (FGC) is rated for 0.788 Msm3/day with max 100 ppm H2

HVint: a strategy for identifying novel protein-protein interactions in Herpes Simplex Virus Type 1

Human herpesviruses are widespread human pathogens with a remarkable impact on worldwide public health. Despite intense decades of research, the molecular details in many aspects of their function remain to be fully characterized. To unravel the details of how these viruses operate, a thorough understanding of the relationships between the involved components is key. Here, we present HVint, a novel protein-protein intra-viral interaction resource for herpes simplex virus type 1 (HSV-1) integrating data from five external sources. To assess each interaction, we used a scoring scheme that takes into consideration aspects such as the type of detection method and the number of lines of evidence. The coverage of the initial interactome was further increased using evolutionary information, by importing interactions reported for other human herpesviruses. These latter interactions constitute, therefore, computational predictions for potential novel interactions in HSV-1. An independent experimental analysis was performed to confirm a subset of our predicted interactions. This subset covers proteins that contribute to nuclear egress and primary envelopment events, including VP26, pUL31, pUL40 and the recently characterized pUL32 and pUL21. Our findings support a coordinated crosstalk between VP26 and proteins such as pUL31, pUS9 and the CSVC complex, contributing to the development of a model describing the nuclear egress and primary envelopment pathways of newly synthesized HSV-1 capsids. The results are also consistent with recent findings on the involvement of pUL32 in capsid maturation and early tegumentation events. Further, they open the door to new hypotheses on virus-specific regulators of pUS9-dependent transport. To make this repository of interactions readily accessible for the scientific community, we also developed a user-friendly and interactive web interface. Our approach demonstrates the power of computational predictions to assist in the design of targeted experiments for the discovery of novel protein-protein interactions