Cluster PEACE observations of electron pressure tensor divergence in the magnetotail

Cluster crossed the magnetotail neutral sheet on four occasions between 16: 38 and 16: 43 UT on 08/17/2003. The four-spacecraft capabilities of Cluster are used to determine spatial gradients from the magnetic field vectors and, for the first time, full electron pressure tensors. We find that the contribution to the electric field from the Hall term (max of similar to 6 mV/m) pointed towards the neutral sheet, whereas that from the electron pressure divergence ( max of similar to 1 mV/m) pointed away from the neutral sheet. The electric field contributions in this direction were closely anti-correlated. During this period Clusters 1 and 4 were sometimes above and below the neutral sheet respectively. This allowed the simultaneous observation of magnetic fields that are interpreted as two quadrants of the Hall magnetic field system. An associated field-aligned current system was detected using the curlometer and moments of the particle distributions

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Software and systems complexity can have a profound impact on information security. Such complexity is not only imposed by the imperative technical challenges of monitored heterogeneous and dynamic (IP and VLAN assignments) network infrastructures, but also through the advances in exploits and malware distribution mechanisms driven by the underground economics. In addition, operational business constraints (disruptions and consequences, manpower, and end-user satisfaction), increase the complexity of the problem domain... Copyright SANS Institut

Quantum theory of damped harmonic oscillator

The exact solutions of the Schrödinger equation for damped harmonic oscillator with pulsating mass and modified Caldirola-Kanai Hamiltonian are evaluated. We also investigated the case of under-damped for the twomodels constructed and the results obtained in both cases do not violate Heisenberg uncertainty principle

Subgenual Cingulum Microstructure Supports Control of Emotional Conflict

This is the final version of the article. Available from Oxford University Press via the DOI in this record.Major depressive disorder (MDD) is associated with specific difficulties in attentional disengagement from negatively valenced material. Diffusion MRI studies have demonstrated altered white matter microstructure in the subgenual cingulum bundle (CB) in individuals with MDD, though the functional significance of these alterations has not been examined formally. This study explored whether individual differences in selective attention to negatively valenced stimuli are related to interindividual differences in subgenual CB microstructure. Forty-six individuals (21 with remitted MDD, 25 never depressed) completed an emotional Stroop task, using happy and angry distractor faces overlaid by pleasant or unpleasant target words and a control gender-based Stroop task. CBs were reconstructed in 38 individuals using diffusion-weighted imaging and tractography, and mean fractional anisotropy (FA) computed for the subgenual, retrosplenial, and parahippocampal subdivisions. No significant correlations were found between FA and performance in the control gender-based Stroop task in any CB region. However, the degree of interference produced by angry face distractors on time to identify pleasant words (emotional conflict) correlated selectively with FA in the subgenual CB (r= -0.53;P= 0.01). Higher FA was associated with reduced interference, irrespective of a diagnosis of MDD, suggesting that subgenual CB microstructure is functionally relevant for regulating attentional bias toward negative interpersonal stimuli.P.A.K. was funded by the Higher Education Funding Council for Wales (HEFCW) and an Academy of Medical Sciences and Wellcome Trust Starter Grant (AJ17102004). M.M. received an EPSRC Doctoral Training Grant. This work was also supported by a Marie Curie fellowship to Marcel Meyer and received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 267171. D.K.J. was funded by HEFCW and received grants from the MS Society, a Wellcome Trust New Investigator Award, a Wellcome Trust Multi User Equipment Grant and Medical Research Council, and Wellcome Trust project grants. A.N.D. was supported by the Wellcome Trust PhD schemes. N.L. was funded by HEFCW. A.D.L. was funded by HEFCW. He also received grants from the ESRC, Wellcome Trust, and NISCHR. Funding to pay the Open Access publication charges for this article was provided by The Wellcome Trust

G protein-coupled receptor GPR37-like 1 regulates adult oligodendrocyte generation

Oligodendrocytes (OLs) continue to be generated from OL precursors (OPs) in the adult mammalian brain. Adult-born OLs are believed to contribute to neural plasticity, learning and memory through a process of “adaptive myelination”, but how adult OL generation and adaptive myelination are regulated remains unclear. Here, we report that the glia-specific G protein-coupled receptor 37-like 1 (GPR37L1) is expressed in subsets of OPs and newly-formed immature OLs in adult mouse brain. We found that OP proliferation and differentiation are inhibited in the corpus callosum of adult Gpr37l1 knockout mice, leading to a reduction in the number of adult-born OLs. Our data raise the possibility that GPR37L1 is mechanistically involved in adult OL generation and adaptive myelination, and suggest that GPR37L1 might be a useful functional marker of OPs that are committed to OL differentiation

Radiocarbon Chronologies and Extinction Dynamics of the Late Quaternary Mammalian Megafauna of the Taimyr Peninsula, Russian Federation

This paper presents 75 new radiocarbon dates based on late Quaternary mammal remains recovered from eastern Taimyr Peninsula and adjacent parts of the northern Siberian lowlands, Russian Federation, including specimens of woolly mammoth (Mammuthus primigenius), steppe bison (Bison priscus), muskox (Ovibos moschatus), moose (Alces alces), reindeer (Rangifer tarandus), horse (Equus caballus) and wolf (Canis lupus). New evidence permits reanalysis of megafaunal extinction dynamics in the Asian high Arctic periphery. Increasingly, radiometric records of individual species show evidence of a gap at or near the Pleistocene/Holocene boundary (PHB). In the past, the PHB gap was regarded as significant only when actually terminal, i.e., when it marked the apparent ‘‘last’’ occurrence of a species (e.g., current ‘‘last’’ occurrence date for woolly mammoth in mainland Eurasia is 9600 yr BP). However, for high Arctic populations of horses and muskoxen the gap marks an interruption rather than extinction, because their radiocarbon records resume, nearly simultaneously, much later in the Holocene. Taphonomic effects, ΔC14 flux, and biased sampling are unlikely explanations for these hiatuses. A possible explanation is that the gap is the signature of an event, of unknown nature, that prompted the nearly simultaneous crash of many megafaunal populations in the high Arctic and possibly elsewhere in Eurasia.

Does prophylactic sotalol and magnesium decrease the incidence of atrial fibrillation following coronary artery bypass surgery: a propensity-matched analysis

BACKGROUND: Atrial fibrillation can occur in up to 40% of patients undergoing coronary surgery. METHODS: We retrospectively analysed 103 consecutive coronary surgery patients under the care of one surgeon between April 2003 and September 2003. These patients received 40 mg of sotalol orally twice daily from the first post-operative day for 6 weeks and 2 g of magnesium intravenously immediately post surgery and on the first post-operative day. We developed a propensity score for the probability of receiving sotalol and magnesium after coronary surgery. 89 patients from the sotalol and magnesium group were successfully matched with 89 unique coronary surgery patients who did not receive either sotalol or magnesium with an identical propensity score. RESULTS: Preoperative characteristics were well matched between groups. There was no significant difference with respect to in-hospital mortality between groups (sotalol and magnesium 1.1% versus control 4.5%; p = 0.17). The incidence of atrial fibrillation in the sotalol and magnesium group was 13.5% compared to 27.0% in the controls (p = 0.025). CONCLUSION: The combination of sotalol and magnesium can significantly reduce the incidence of post-operative atrial fibrillation following coronary surgery

Antimicrobial Resistance, Class 1 Integrons, and Genomic Island 1 in Salmonella Isolates from Vietnam

BACKGROUND: The objective was to investigate the phenotypic and genotypic resistance and the horizontal transfer of resistance determinants from Salmonella isolates from humans and animals in Vietnam. METHODOLOGY/PRINCIPAL FINDINGS: The susceptibility of 297 epidemiologically unrelated non-typhoid Salmonella isolates was investigated by disk diffusion assay. The isolates were screened for the presence of class 1 integrons and Salmonella genomic island 1 by PCR. The potential for the transfer of resistance determinants was investigated by conjugation experiments. Resistance to gentamicin, kanamycin, chloramphenicol, streptomycin, trimethoprim, ampicillin, nalidixic acid, sulphonamides, and tetracycline was found in 13 to 50% of the isolates. Nine distinct integron types were detected in 28% of the isolates belonging to 11 Salmonella serovars including S. Tallahassee. Gene cassettes identified were aadA1, aadA2, aadA5, bla(PSE-1), bla(OXA-30), dfrA1, dfrA12, dfrA17, and sat, as well as open reading frames with unknown functions. Most integrons were located on conjugative plasmids, which can transfer their antimicrobial resistance determinants to Escherichia coli or Salmonella Enteritidis, or with Salmonella Genomic Island 1 or its variants. The resistance gene cluster in serovar Emek identified by PCR mapping and nucleotide sequencing contained SGI1-J3 which is integrated in SGI1 at another position than the majority of SGI1. This is the second report on the insertion of SGI1 at this position. High-level resistance to fluoroquinolones was found in 3 multiresistant S. Typhimurium isolates and was associated with mutations in the gyrA gene leading to the amino acid changes Ser83Phe and Asp87Asn. CONCLUSIONS: Resistance was common among Vietnamese Salmonella isolates from different sources. Legislation to enforce a more prudent use of antibiotics in both human and veterinary medicine should be implemented by the authorities in Vietnam

Reconstructions of deltaic environments from Holocene palynological records in the Volga delta, northern Caspian Sea

This article was made available through open access by the Brunel Open Access Publishing Fund.New palynological and ostracod data are presented from the Holocene Volga delta, obtained from short cores and surface samples collected in the Damchik region, near Astrakhan, Russian Federation in the northern Caspian Sea. Four phases of delta deposition are recognized and constrained by accelerated mass spectrometry (AMS) radiocarbon ages. Palynological records show that erosive channels, dunes (Baer hills) and inter-dune lakes were present during the period 11,500–8900 cal. BP at the time of the Mangyshlak Caspian lowstand. The period 8900–3770 cal. BP was characterized regionally by extensive steppe vegetation, with forest present at times with warmer, more humid climates, and with halophytic and xerophytic vegetation present at times of drought. The period 3770–2080 cal. BP was a time of active delta deposition, with forest or woodland close to the delta, indicating relatively warm and humid climates and variable Caspian Sea levels. From 2080 cal. BP to the present-day, aquatic pollen is frequent in highstand intervals and herbaceous pollen and fungal hyphae frequent in lowstand intervals. Soils and incised valley sediments are associated with the regional Derbent regression and may be time-equivalent with the ‘Medieval Warm Period’. Fungal spores are an indicator of erosional or aeolian processes, whereas fungal hyphae are associated with soil formation. Freshwater algae, ostracods and dinocysts indicate mainly freshwater conditions during the Holocene with minor brackish influences. Dinocysts present include Spiniferites cruciformis, Caspidinium rugosum, Impagidinium caspienense and Pterocysta cruciformis, the latter a new record for the Caspian Sea. The Holocene Volga delta is a partial analogue for the much larger oil and gas bearing Mio-Pliocene palaeo-Volga delta.Funding for the data collection and field work was provided from the following sources: 1 – IGCP-UNESCO 2003–2008 (Project 481 CASPAGE, Dating Caspian Sea Level Change); 2 – NWO, Netherlands Science Foundation and RFFI, Russian Science Foundation 2005–2008 (Programme: ‘VHR Seismic Stratigraphy and Paleoecology of the Holocene Volga Delta’); and 3 – BP Exploration (Caspian Sea) Sea Ltd. (Azeri-Chirag-Gunashli) 2005–2008 (‘Unravelling the Small-Scale Stratigraphy and Sediment Dynamics of the Modern Volga Delta Using VHR Marine Geophysics’). The palynological work was funded jointly by BP Exploration (Caspian Sea) Ltd., Delft University of Technology and KrA Stratigraphic Ltd. Ostracod analyses were funded by StrataData Ltd. and funding for two additional radiocarbon dates provided by Deltares