28,639 research outputs found

    Locating the critical end point using the linear sigma model coupled to quarks

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    We use the linear sigma model coupled to quarks to compute the effective potential beyond the mean field approximation, including the contribution of the ring diagrams at finite temperature and baryon density. We determine the model couplings and use them to study the phase diagram in the baryon chemical potential-temperature plane and to locate the Critical End Point.Comment: 8 pages, 2 figures, conference paper from ISMD 201

    Report of the Biological Data Products Workshop of the European Marine Observation and Data Network (EMODnet)

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    From 25 till 26 of February 2010, the Flanders Marine Institute (VLIZ) organized a workshop on biological data products in Oostende, Belgium. This workshop was organized within the framework of the upcoming European Marine Observation and Data Network, EMODnet, launched by the Maritime Policy of the European Commission. 57 participants from 42 excellent institutes involved in marine biological data collection, marine research and marine policy across Europe attended the workshop. The workshop had three main objectives: (1) to discuss the marine biological data availability and gaps in Europe, (2) to demonstrate the prototype of the EMODnet biological data portal to different user groups and (3) to define a set of derived biological data products relevant for private bodies, public authorities and researchers. A huge amount of reliable European marine biological data and information was presented to the public. These data are available and despite some temporal, spatial and taxonomic limitations, data are already very useful for analyses. There was a consensus amongst workshop participants that the look and feel and functionalities of the EMODnet biological prototype portal, visualizing both data observations and data products, were meeting the requirements. Although the user groups were very diverse, being people from the scientific community, people involved in the European marine policy and coastal and marine practitioners, a number of striking similarities amongst data products were found. In the different user discussion groups, four different sets of marine biological data products were identified as priority biological data products being: (1) species distribution maps and trends, (2) species sensitivity and vulnerability maps, (3) species attributes (functional groups, HAB’s, invasive species, red list or protected species) and (4) biodiversity indices. Within the biological EMODnet preparatory action, a few data analysis workshops will be organized in the near future (2011) to produce some of the data products identified during this workshop. The same community and other relevant stakeholders, identified during the meeting will be involved in this process

    Post-growth annealing of GaMnAs under As capping - an alternative way to increase Tc

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    We demonstrate that in situ post-growth annealing of GaMnAs layers under As capping is adequate for achieving high Curie temperatures (Tc) in a similar way as ex situ annealing in air or in N2 atmosphere practiced earlier.Comment: 13 pages, 4 figure

    Human papillomavirus E2 regulates SRSF3 (SRp20) to promote capsid protein expression in infected differentiated keratinocytes

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    The human papillomavirus (HPV) life cycle is tightly linked to differentiation of the infected epithelial cell suggesting a sophisticated interplay between host cell metabolism and virus replication. Previously we demonstrated in differentiated keratinocytes in vitro and in vivo that HPV16 infection caused increased levels of the cellular SR splicing factors (SRSFs) SRSF1 (ASF/SF2), SRSF2 (SC35) and SRSF3 (SRp20). Moreover, the viral E2 transcription and replication factor that is expressed at high levels in differentiating keratinocytes could bind and control activity of the SRSF1 gene promoter. Here we reveal that E2 proteins of HPV16 and HPV31 control expression of SRSFs 1, 2 and 3 in a differentiation-dependent manner. E2 has the greatest trans-activation effect on expression of SRSF3. siRNA depletion experiments in two different models of the HPV16 life cycle (W12E and NIKS16) and one model of the HPV31 life cycle (CIN612-9E) revealed that only SRSF3 contributed significantly to regulation of late events in the virus life cycle. Increased levels of SRSF3 are required for L1 mRNA and capsid protein expression. Capsid protein expression was regulated specifically by SRSF3 and appeared independent of other SRSFs. Taken together these data suggest a significant role of the HPV E2 protein in regulating late events in the HPV life cycle through transcriptional regulation of SRSF3 expression. IMPORTANCE Human papillomavirus replication is accomplished in concert with differentiation of the infected epithelium. Virus capsid protein expression is confined to the upper epithelial layers so as to avoid immune detection. In this study we demonstrate that the viral E2 transcription factor activates the promoter of the cellular SRSF3 RNA processing factor. SRSF3 is required for expression of the E4̂L1 mRNA and so controls expression of the HPV L1 capsid protein. Thus we reveal a new dimension of virus-host interaction crucial for production of infectious virus. SRSF proteins are known drug targets. Therefore, this study provides an excellent basis for developing strategies to regulate capsid protein production in the infected epithelium and production of new virions

    The Transition State in a Noisy Environment

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    Transition State Theory overestimates reaction rates in solution because conventional dividing surfaces between reagents and products are crossed many times by the same reactive trajectory. We describe a recipe for constructing a time-dependent dividing surface free of such recrossings in the presence of noise. The no-recrossing limit of Transition State Theory thus becomes generally available for the description of reactions in a fluctuating environment

    Mapping the Kinematical Regimes of Semi-Inclusive Deep Inelastic Scattering

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    We construct a language for identifying kinematical regions of transversely differential semi-inclusive deep inelastic scattering cross sections with particular underlying partonic pictures, especially in regions of moderate to low QQ where sensitivity to kinematical effects outside the usual very high energy limit becomes non-trivial. The partonic pictures map to power law expansions whose leading contributions ultimately lead to well-known QCD factorization theorems. We propose methods for estimating the consistency of any particular region of overall hadronic kinematics with the kinematics of a given underlying partonic picture. The basic setup of kinematics of semi-inclusive deep inelastic scattering is also reviewed in some detail.Comment: 37 pages, 11 Figure

    Predicting magnetopause crossings at geosynchronous orbit during the Halloween storms

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    [1] In late October and early November of 2003, the Sun unleashed a powerful series of events known as the Halloween storms. The coronal mass ejections launched by the Sun produced several severe compressions of the magnetosphere that moved the magnetopause inside of geosynchronous orbit. Such events are of interest to satellite operators, and the ability to predict magnetopause crossings along a given orbit is an important space weather capability. In this paper we compare geosynchronous observations of magnetopause crossings during the Halloween storms to crossings determined from the Lyon-Fedder-Mobarry global magnetohydrodynamic simulation of the magnetosphere as well to predictions of several empirical models of the magnetopause position. We calculate basic statistical information about the predictions as well as several standard skill scores. We find that the current Lyon-Fedder-Mobarry simulation of the storm provides a slightly better prediction of the magnetopause position than the empirical models we examined for the extreme conditions present in this study. While this is not surprising, given that conditions during the Halloween storms were well outside the parameter space of the empirical models, it does point out the need for physics-based models that can predict the effects of the most extreme events that are of significant interest to users of space weather forecasts

    The cloned RNA polymerase II transcription factor IID selects RNA polymerase III to transcribe the human U6 gene in vitro

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    Although the human U2 and U6 snRNA genes are transcribed by different RNA polymerases (i.e., RNA polymerases II and III, respectively), their promoters are very similar in structure. Both contain a proximal sequence element (PSE) and an octamer motif-containing enhancer, and these elements are interchangeable between the two promoters. The RNA polymerase III specificity of the U6 promoter is conferred by a single A/T-rich element located around position -25. Mutation of the A/T-rich region converts the U6 promoter into an RNA polymerase II promoter, whereas insertion of the A/T-rich region into the U2 promoter converts that promoter into an RNA polymerase III promoter. We show that this A/T-rich element can be replaced by a number of TATA boxes derived from mRNA promoters transcribed by RNA polymerase II with little effect on RNA polymerase III transcription. Furthermore, the cloned RNA polymerase II transcription factor TFIID both binds to the U6 A/T-rich region and directs accurate RNA polymerase III transcription in vitro. Mutations in the U6 A/T-rich region that convert the U6 promoter into an RNA polymerase II promoter also abolish TFIID binding. Together, these observations suggest that in the human snRNA promoters, unlike in mRNA promoters, binding of TFIID directs the assembly of RNA polymerase III transcription complexes, whereas the lack of TFIID binding results in the assembly of RNA polymerase II snRNA transcription complexes
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