450 research outputs found

    Methods for removal of unwanted signals from gravity time-series : comparison using linear techniques complemented with analysis of system dynamics

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    We thanks the participants of the 35th General Assembly of the European Seismological Commission for comments on preliminary results. The authors are grateful to all IGETS contributors, particularly to the station operators and to ISDC/GFZ-Potsdam for providing the original gravity data used in this study. We also thank the developers of ATLANTIDA3.1 and UTide. Part of this work was performed using the ICSMB High Performance Computing Cluster, University of Aberdeen. We also thanks M. Thiel and A. Moura for reviewing a preliminary version and making comments on the methods section and M.A. Ara´ujo for comments on Lyapunov exponents. Funding: A. Valencio is supported by CNPq, Brazil [206246/2014-5]; and received a travel grant from the School of Natural and Computing Sciences, University of Aberdeen [PO2073498], for a presentation including preliminary results.Peer reviewedPostprintPublisher PD

    Tight-Binding model for semiconductor nanostructures

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    An empirical scpa3s_cp^3_a tight-binding (TB) model is applied to the investigation of electronic states in semiconductor quantum dots. A basis set of three pp-orbitals at the anions and one ss-orbital at the cations is chosen. Matrix elements up to the second nearest neighbors and the spin-orbit coupling are included in our TB-model. The parametrization is chosen so that the effective masses, the spin-orbit-splitting and the gap energy of the bulk CdSe and ZnSe are reproduced. Within this reduced scpa3s_cp_a^3 TB-basis the valence (p-) bands are excellently reproduced and the conduction (s-) band is well reproduced close to the Γ\Gamma-point, i.e. near to the band gap. In terms of this model much larger systems can be described than within a (more realistic) sp3ssp^3s^*-basis. The quantum dot is modelled by using the (bulk) TB-parameters for the particular material at those sites occupied by atoms of this material. Within this TB-model we study pyramidal-shaped CdSe quantum dots embedded in a ZnSe matrix and free spherical CdSe quantum dots (nanocrystals). Strain-effects are included by using an appropriate model strain field. Within the TB-model, the strain-effects can be artifically switched off to investigate the infuence of strain on the bound electronic states and, in particular, their spatial orientation. The theoretical results for spherical nanocrystals are compared with data from tunneling spectroscopy and optical experiments. Furthermore the influence of the spin-orbit coupling is investigated

    Yours ever (well, maybe): Studies and signposts in letter writing

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    Electronic mail and other digital communications technologies seemingly threaten to end the era of handwritten and typed letters, now affectionately seen as part of snail mail. In this essay, I analyze a group of popular and scholarly studies about letter writing-including examples of pundits critiquing the use of e-mail, etiquette manuals advising why the handwritten letter still possesses value, historians and literary scholars studying the role of letters in the past and what it tells us about our present attitudes about digital communications technologies, and futurists predicting how we will function as personal archivists maintaining every document including e-mail. These are useful guideposts for archivists, providing both a sense of the present and the past in the role, value and nature of letters and their successors. They also provide insights into how such documents should be studied, expanding our gaze beyond the particular letters, to the tools used to create them and the traditions dictating their form and function. We also can discern a role for archivists, both for contributing to the literature about documents and in using these studies and commentaries, suggesting not a new disciplinary realm but opportunities for new interdisciplinary work. Examining a documentary form makes us more sensitive to both the innovations and traditions as it shifts from the analog to the digital; we can learn not to be caught up in hysteria or nostalgia about one form over another and archivists can learn about what they might expect in their labors to document society and its institutions. At one time, paper was part of an innovative technology, with roles very similar to the Internet and e-mail today. It may be that the shifts are far less revolutionary than is often assumed. Reading such works also suggests, finally, that archivists ought to rethink how they view their own knowledge and how it is constructed and used. © 2010 Springer Science+Business Media B.V

    Hypoxia Reduces Arylsulfatase B Activity and Silencing Arylsulfatase B Replicates and Mediates the Effects of Hypoxia

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    This report presents evidence of 1) a role for arylsulfatase B (ARSB; N-acetylgalactosamine-4-sulfatase) in mediating intracellular oxygen signaling; 2) replication between the effects of ARSB silencing and hypoxia on sulfated glycosaminoglycan content, cellular redox status, and expression of hypoxia-associated genes; and 3) a mechanism whereby changes in chondroitin-4-sulfation that follow either hypoxia or ARSB silencing can induce transcriptional changes through galectin-3. ARSB removes 4-sulfate groups from the non-reducing end of chondroitin-4-sulfate and dermatan sulfate and is required for their degradation. For activity, ARSB requires modification of a critical cysteine residue by the formylglycine generating enzyme and by molecular oxygen. When primary human bronchial and human colonic epithelial cells were exposed to 10% O2×1 h, ARSB activity declined by ∼41% and ∼30% from baseline, as nuclear hypoxia inducible factor (HIF)-1α increased by ∼53% and ∼37%. When ARSB was silenced, nuclear HIF-1α increased by ∼81% and ∼61% from baseline, and mRNA expression increased to 3.73 (±0.34) times baseline. Inversely, ARSB overexpression reduced nuclear HIF-1α by ∼37% and ∼54% from baseline in the epithelial cells. Hypoxia, like ARSB silencing, significantly increased the total cellular sulfated glycosaminoglycans and chondroitin-4-sulfate (C4S) content. Both hypoxia and ARSB silencing had similar effects on the cellular redox status and on mRNA expression of hypoxia-associated genes. Transcriptional effects of both ARSB silencing and hypoxia may be mediated by reduction in galectin-3 binding to more highly sulfated C4S, since the galectin-3 that co-immunoprecipitated with C4S declined and the nuclear galectin-3 increased following ARSB knockdown and hypoxia

    The effects of nitroxyl (HNO) on soluble guanylate cyclase activity: interactions at ferrous heme and cysteine thiols

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    It has been previously proposed that nitric oxide (NO) is the only biologically relevant nitrogen oxide capable of activating the enzyme soluble guanylate cyclase (sGC). However, recent reports implicate HNO as another possible activator of sGC. Herein, we examine the affect of HNO donors on the activity of purified bovine lung sGC and find that, indeed, HNO is capable of activating this enzyme. Like NO, HNO activation appears to occur via interaction with the regulatory ferrous heme on sGC. Somewhat unexpectedly, HNO does not activate the ferric form of the enzyme. Finally, HNO-mediated cysteine thiol modification appears to also affect enzyme activity leading to inhibition. Thus, sGC activity can be regulated by HNO via interactions at both the regulatory heme and cysteine thiols

    Yoga after Stroke Leads to Multiple Physical Improvements

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    poster abstractMethods: Forty-seven individuals with chronic stroke were recruited and randomized 3:1 to yoga or waitlist control (usual care). The yoga group completed one hour yoga sessions twice a week for 8 weeks. Yoga was taught by a yoga therapist and included modified physical postures in seated, standing, and supine positions and included yoga breathing, bilateral movements, concluding with relaxation. Assessments before and after the 8 weeks included: flexibility via passive range of motion (PROM) for the hamstrings (HS) and active range of motion (AROM) for hip flexion, cervical rotation, and cervical lateral flexion; strength with the chair to stand and arm curl and hip flexion manual muscle test; and walking capacity with the 6 minute walk test. We compared groups with a t-test/Mann Whitney. We used paired t-tests/Wilcoxon non-parametric tests to compare baseline and 8-week data

    Persistent anthrax as a major driver of wildlife mortality in a tropical rainforest

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    Anthrax is a globally important animal disease and zoonosis. Despite this, our current knowledge of anthrax ecology is largely limited to arid ecosystems, where outbreaks are most commonly reported. Here we show that the dynamics of an anthrax-causing agent, Bacillus cereus biovar anthracis, in a tropical rainforest have severe consequences for local wildlife communities. Using data and samples collected over three decades, we show that rainforest anthrax is a persistent and widespread cause of death for a broad range of mammalian hosts. We predict that this pathogen will accelerate the decline and possibly result in the extirpation of local chimpanzee (Pan troglodytes verus) populations. We present the epidemiology of a cryptic pathogen and show that its presence has important implications for conservation

    Self-Renewal of Acute Lymphocytic Leukemia Cells Is Limited by the Hedgehog Pathway Inhibitors Cyclopamine and IPI-926

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    Conserved embryonic signaling pathways such as Hedgehog (Hh), Wingless and Notch have been implicated in the pathogenesis of several malignancies. Recent data suggests that Hh signaling plays a role in normal B-cell development, and we hypothesized that Hh signaling may be important in precursor B-cell acute lymphocytic leukemia (B-ALL). We found that the expression of Hh pathway components was common in human B-ALL cell lines and clinical samples. Moreover, pathway activity could be modulated by Hh ligand or several pathway inhibitors including cyclopamine and the novel SMOOTHENED (SMO) inhibitor IPI-926. The inhibition of pathway activity primarily impacted highly clonogenic B-ALL cells expressing aldehyde dehydrogenase (ALDH) by limiting their self-renewal potential both in vitro and in vivo. These data demonstrate that Hh pathway activation is common in B-ALL and represents a novel therapeutic target regulating self-renewal and persistence of the malignant clone

    The federal government commissioner for patient issues in Germany: initial analysis of the user inquiries

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    BACKGROUND: The political objective in many countries worldwide is to give better consideration to the interests of patients within the health system. The establishment of a federal government commissioner for the issues of patients in the health system in Germany in 2004 is part of these endeavours. The structure and field of activities of this institution has been unique so far. This study investigates for the first time the inquiries the commissioner receives from the public. METHODS: A 33% sampling (n = 850) of the written inquiries (correspondence and e-mails) addressed to the commissioner in the first six months of the year 2005 (n = 2580) was investigated. In a procedure comprising combined qualitative and quantitative levels, the material was thematically encoded and the inquiries allocated to the resulting categories (multiple nominations). The results are presented in descriptive form and investigated especially with respect to sex and age-specific differences. The interdependences between the categorized criteria are analysed. RESULTS: The inquirers are equally spread out amongst the sexes (49% women, 51% men). Older persons outweigh the younger (69% over 60 years). In most cases the issues take the form of claims (72%, n = 609). In every fifth inquiry (n = 168) the personal financial burden for health services is considered as being too high; about equally high (n = 159) is the proportion of persons who criticize the communication with health professionals, especially hospitals and doctors' surgeries. Every third who mentions a medical practice uses terms such as "uncertainty" and "anxiety". It is conspicuous that men more often than women write that they feel unfairly treated in the health system (62% vs. 38%, p < 0.05). CONCLUSION: Predominantly older persons seek the assistance of the federal government commissioner for patient issues. Considerable uncertainty and anxiety with respect to services and charges within the system of the German health insurances become evident. It is not possible from the data to draw conclusions concerning the impact of the commissioner's work on the health system. Nor do we gain any knowledge about the usefulness of the service for the individual. Therefore, evaluation of the political impact and the user satisfaction should follow
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