52 research outputs found
Quantum Dimensional Zeeman Effect in the Magneto-optical Absorption Spectrum for Quantum Dot - Impurity Center Systems
Magneto-optical properties of the quantum dot - impurity center (QD-IC)
systems synthesized in a transparent dielectric matrix are considered. For the
QD one-electron state description the parabolic model of the confinement
potential is used. Within the framework of zero-range potential model and the
effective mass approach, the light impurity absorption coefficient for the case
of transversal polarization with respect to the applied magnetic field
direction, with consideration of the QD size dispersion, has been analytically
calculated. It is shown that for the case of transversal polarization the light
impurity absorption spectrum is characterized by the quantum dimensional Zeeman
effect.Comment: 18 pages, 1 figure, PDF fil
New genetic loci link adipose and insulin biology to body fat distribution.
Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms
The Constrained Maximal Expression Level Owing to Haploidy Shapes Gene Content on the Mammalian X Chromosome.
X chromosomes are unusual in many regards, not least of which is their nonrandom gene content. The causes of this bias are commonly discussed in the context of sexual antagonism and the avoidance of activity in the male germline. Here, we examine the notion that, at least in some taxa, functionally biased gene content may more profoundly be shaped by limits imposed on gene expression owing to haploid expression of the X chromosome. Notably, if the X, as in primates, is transcribed at rates comparable to the ancestral rate (per promoter) prior to the X chromosome formation, then the X is not a tolerable environment for genes with very high maximal net levels of expression, owing to transcriptional traffic jams. We test this hypothesis using The Encyclopedia of DNA Elements (ENCODE) and data from the Functional Annotation of the Mammalian Genome (FANTOM5) project. As predicted, the maximal expression of human X-linked genes is much lower than that of genes on autosomes: on average, maximal expression is three times lower on the X chromosome than on autosomes. Similarly, autosome-to-X retroposition events are associated with lower maximal expression of retrogenes on the X than seen for X-to-autosome retrogenes on autosomes. Also as expected, X-linked genes have a lesser degree of increase in gene expression than autosomal ones (compared to the human/Chimpanzee common ancestor) if highly expressed, but not if lowly expressed. The traffic jam model also explains the known lower breadth of expression for genes on the X (and the Z of birds), as genes with broad expression are, on average, those with high maximal expression. As then further predicted, highly expressed tissue-specific genes are also rare on the X and broadly expressed genes on the X tend to be lowly expressed, both indicating that the trend is shaped by the maximal expression level not the breadth of expression per se. Importantly, a limit to the maximal expression level explains biased tissue of expression profiles of X-linked genes. Tissues whose tissue-specific genes are very highly expressed (e.g., secretory tissues, tissues abundant in structural proteins) are also tissues in which gene expression is relatively rare on the X chromosome. These trends cannot be fully accounted for in terms of alternative models of biased expression. In conclusion, the notion that it is hard for genes on the Therian X to be highly expressed, owing to transcriptional traffic jams, provides a simple yet robustly supported rationale of many peculiar features of X's gene content, gene expression, and evolution
Die Evaluation von Beratungsleistungen : Prozesse der Wahrnehmung und Bewertung
Die Beratungsbranche hat in den vergangenen Jahrzehnten einen immensen Bedeutungszuwachs erfahren. Nicht nur Manager, sondern auch Politiker nehmen immer häufiger den professionellen Rat von Unternehmensberatungen in Anspruch.
Berit Ernst geht der zentralen und in der Forschung bisher kaum thematisierten Frage nach, wie Bewertungen über die Leistungen von Unternehmensberatungen zustande kommen. In einer qualitativen empirischen Untersuchung werden in Interviews mit Managern und Beratern Beratungsprojekte rekonstruiert und die komplexen Zusammenhänge zwischen verschiedenen Faktoren wie der Berater-Klienten-Beziehung, der Motivation sowie den Erfahrungen der Beteiligten und den über die Beratungsleistung gebildeten Urteilen aufgezeigt. Diese Faktoren entziehen sich einer auf technisch-instrumentelle Aspekte fokussierten Evaluation, beeinflussen aber maßgeblich die Wahrnehmung von Erfolg bzw. Misserfolg und sind daher besonders wichtig für die Zusammenarbeit zwischen Beratern und Klienten. Eine objektive Evaluation scheint infolgedessen nicht möglich und wird in der Praxis auch kaum angestrebt
A comparison of hydrological climate services at different scales by users and scientists
Given the current proliferation of climate change services, how should a user judge which one is most relevant for a specific case? In this study, climate researchers and users compare continental, national and locally tailored climate change services for two case studies in Sweden with clear adaptation needs. The case studies addressed the organising committee of the large ski-racing event, Vasaloppet, for which snow availability is a concern now and in the future, and a small municipality in Sweden (Karlstad) that is prone to flooding. After meetings and online discussions with users, researchers locally tailored a service by reanalysing the data behind the national climate service. We then compared these locally tailored results with available, comparable data from the pan-European and national climate services, including the projected changes and the uncertainties provided by each service. We found that different climate change services provided different indicators, and magnitudes and directions of climate change. Differences across services are unavoidable, and limitations of climate change services are a reality of the nature of projecting an ultimately uncertain future. Therefore, we call for clearer, more explicit communication of what a climate change service provides, and detailed explanations of the limitations of climate services regarding variables, locations, scales, as well as other uncertainties. We also find that value can be added to existing climate change services by tailoring climate service outputs for a specific location or specific user requirements. Keywords: Climate services, Climate change services, Climate adaptation, Tailored climate services, Water resources, Stakeholder
Crustal composition of the Møre Margin and compilation of a conjugate Atlantic margin transect
Highlights
• The basement at the mid-Norwegian Møre Margin is dominantly felsic in composition.
• A lower crustal body is interpreted as a mixture of continental blocks and eclogite.
• The thickness of the outer lower crustal body is twice as thick on the East Greenland Margin.
• The thinning during this first phase of post-Caledonian extension was highest for proto Norway.
Abstract
The inner part of the volcanic, passive Møre Margin, mid-Norway, expresses an unusual abrupt thinning from high onshore topography with a thick crust to an offshore basin with thin crystalline crust. Previous P-wave modeling of wide-angle seismic data revealed the presence of a high-velocity (7.7–8.0 km/s) body in the lower crust in this transitional region. These velocities are too high to be readily interpreted as Early Cenozoic intrusions, a model often invoked to explain lower crustal high-velocity bodies in the region. We present a Vp/Vs model, derived from the modeling of wide-angle seismic data, acquired by use of Ocean Bottom Seismograph horizontal components. The modeling suggests dominantly felsic composition of the crust. An average Vp/Vs value for the lower crustal body is modeled at 1.77, which is compatible with a mixture of continental blocks and Caledonian eclogites. The results are compiled with earlier results into a transect extending from onshore Norway to onshore Greenland. Back-stripping of the transect to Early Cenozoic indicates asymmetric conjugate magmatism related to the continental break-up. Further back-stripping to the time when most of the Caledonian mountain range had collapsed indicates that the thinning during the first phase of extension was about 25% higher for proto Norway than proto Greenland
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