104 research outputs found

    Towards Building Wind Tunnels for Data Center Design

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    Data center design is a tedious and expensive process. Recently, this process has become even more challenging as users of cloud services expect to have guaranteed levels of availability, durability and performance. A new challenge for the service providers is to find the most cost-effective data center design and configuration that will accommodate the users ’ expectations, on ever-changing workloads, and constantly evolving hardware and software components. In this paper, we argue that data center design should become a systematic process. First, it should be done using an integrated approach that takes into account both the hardware and the software interdependencies, and their impact on users ’ expectations. Second, it should be performed in a “wind tunnel”, which uses large-scale simulation to systematically explore the impact of a data center configuration on both the users ’ and the service providers ’ requirements. We believe that this is the first step towards systematic data center design – an exciting area for future research. 1

    Homocysteine in cerebrovascular disease: An independent risk factor for subcortical vascular encephalopathy

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    Hyperhomocysteinemia is a risk factor for obstructive large-vessel disease. Here, we studied plasma concentrations of homocysteine and vitamins in patients suffering from subcortical vascular encephalopathy (SVE), a cerebral small-vessel disease leading to dementia. These results were compared to the homocysteine and vitamin plasma concentrations from patients with cerebral large vessel disease and healthy control subjects. Plasma concentrations of homocysteine, vascular risk factors and vitamin status (B-6, B-12, folate) were determined in 82 patients with subcortical vascular encephalopathy, in 144 patients with cerebral large-vessel disease and in 102 control subjects. Patients with SVE, but not those with cerebral large-vessel disease, exhibited pathologically increased homocysteine concentrations in comparison with control subjects without cerebrovascular disease. Patients with SVE also showed lower vitamin B6 values in comparison to subjects without cerebrovascular disease. Logistic regression analysis showed that homocysteine is associated with the highest risk for SVE (odds ratio 5.7; CI 2.5-12.9) in comparison to other vascular risk factors such as hypertension, age and smoking. These observations indicate that hyperhomocysteinemia is a strong independent risk factor for SVE

    Coherent QCD phenomena in the Coherent Pion-Nucleon and Pion-Nucleus Production of Two Jets at High Relative Momenta

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    We use QCD to compute the cross section for coherent production of a di-jet (treated as a qqˉq\bar q moving at high relative transverse momentum,Îșt\kappa_t ). In the target rest frame,the space-time evolution of this reaction is dominated by the process in which the high Îșt\kappa_t qqˉq\bar q component of the pion wave function is formed before reaching the target. It then interacts through two gluon exchange. In the approximation of keeping the leading order in powers of αs\alpha_s and all orders in αsln⁥(Îșt2/k02),\alpha_{s}\ln(\kappa_{t}^2/k_{0}^2), the amplitudes for other processes are shown to be smaller at least by a power of αs\alpha_{s}. The resulting dominant amplitude is proportional to z(1−z)Îșt−4z(1-z) \kappa_t^{-4} (zz is the fraction light-cone(+)momentum carried by the quark in the final state) times the skewed gluon distribution of the target. For the pion scattering by a nuclear target, this means that at fixed xN=2Îșt2/sx_{N}= 2\kappa_{t}^2/s (but Îșt2→∞\kappa_{t}^2\to \infty) the nuclear process in which there is only a single interaction is the most important one to contribute to the reaction. Thus in this limit color transparency phenomena should occur.These findings are in accord with E971 experiment at FNAL. We also re-examine a potentially important nuclear multiple scattering correction which is positive and ∝A1/3/Îșt4\propto A^{1/3}/\kappa_t^4. The meaning of the signal obtained from the experimental measurement of pion diffraction into two jets is also critically examined and significant corrections are identified.We show also that for values of Îșt\kappa_t achieved at fixed target energies, di-jet production by the e.m. field of the nucleus leads to an insignificant correction which gets more important as Îșt\kappa_t increases.Comment: 23 pages, 9 figure

    Taming of the shrewd: novel eukaryotic genes from RNA viruses

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    Genomes of several yeast species contain integrated DNA copies of complete genomes or individual genes of non-retroviral double-strand RNA viruses as reported in a recent BMC Biology article by Taylor and Bruenn. The integrated virus-specific sequences are at least partially expressed and seem to evolve under pressure of purifying selection, indicating that these are functional genes. Together with similar reports on integrated copies of some animal RNA viruses, these results suggest that integration of DNA copies of non-reverse-transcribing RNA viruses might be much more common than previously thought. The integrated copies could contribute to acquired immunity to the respective viruses

    Effects of state-wide implementation of the Los Angeles Motor Scale for triage of stroke patients in clinical practice

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    The prehospital identification of stroke patients with large-vessel occlusion (LVO), that should be immediately transported to a thrombectomy capable centre is an unsolved problem. Our aim was to determine whether implementation of a state-wide standard operating procedure (SOP) using the Los Angeles Motor Scale (LAMS) is feasible and enables correct triage of stroke patients to hospitals offering (comprehensive stroke centres, CSCs) or not offering (primary stroke centres, PSCs) thrombectomy. Prospective study involving all patients with suspected acute stroke treated in a 4-month period in a state-wide network of all stroke-treating hospitals (eight PSCs and two CSCs). Primary endpoint was accuracy of the triage SOP in correctly transferring patients to CSCs or PSCs. Additional endpoints included the number of secondary transfers, the accuracy of the LAMS for detection of LVO, apart from stroke management metrics. In 1123 patients, use of a triage SOP based on the LAMS allowed triage decisions according to LVO status with a sensitivity of 69.2% (95% confidence interval (95%-CI): 59.0–79.5%) and a specificity of 84.9% (95%-CI: 82.6–87.3%). This was more favourable than the conventional approach of transferring every patient to the nearest stroke-treating hospital, as determined by geocoding for each patient (sensitivity, 17.9% (95%-CI: 9.4–26.5%); specificity, 100% (95%-CI: 100–100%)). Secondary transfers were required for 14 of the 78 (17.9%) LVO patients. Regarding the score itself, LAMS detected LVO with a sensitivity of 67.5% (95%-CI: 57.1–78.0%) and a specificity of 83.5% (95%-CI: 81.0–86.0%). State-wide implementation of a triage SOP requesting use of the LAMS tool is feasible and improves triage decision-making in acute stroke regarding the most appropriate target hospital

    Bis(diethylamino)(pentafluorophenyl)phosphane – a Push–Pull Phosphane Available for Coordination

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    A facile large-scale synthesis of the “push–pull”-substituted ligand bis(diethylamino)(pentafluorophenyl)phosphane is reported. A selenophosphorane as well as complexes with CuI and PdCl2, can be formed almost quantitatively from suitable starting materials. The PdII complex shows a square-planar coordination with significant distortions of the Cl–Pd–Cl moiety in the solid state. In contrast, the phosphane ligand exhibits a large flexibility in the trigonal-planar coordination of the Cu salt, as proven by X-ray crystallography. C–C cross-coupling reactions and 1,3-dipolar cycloadditions have been tested for the PdII and CuI complexes, respectively. Whereas the reactivity of the PdII complex is good at low temperature, the CuI complex reveals remarkable reaction rates at temperatures up to 130 °C. Furthermore, the CuI-catalyzed azide/alkyne 1,3-dipolar cycloaddition was successfully adapted for flow conditions

    Concept of the Munich/Augsburg Consortium Precision in Mental Health for the German Center of Mental Health

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    The Federal Ministry of Education and Research (BMBF) issued a call for a new nationwide research network on mental disorders, the German Center of Mental Health (DZPG). The Munich/Augsburg consortium was selected to participate as one of six partner sites with its concept “Precision in Mental Health (PriMe): Understanding, predicting, and preventing chronicity.” PriMe bundles interdisciplinary research from the Ludwig-Maximilians-University (LMU), Technical University of Munich (TUM), University of Augsburg (UniA), Helmholtz Center Munich (HMGU), and Max Planck Institute of Psychiatry (MPIP) and has a focus on schizophrenia (SZ), bipolar disorder (BPD), and major depressive disorder (MDD). PriMe takes a longitudinal perspective on these three disorders from the at-risk stage to the first-episode, relapsing, and chronic stages. These disorders pose a major health burden because in up to 50% of patients they cause untreatable residual symptoms, which lead to early social and vocational disability, comorbidities, and excess mortality. PriMe aims at reducing mortality on different levels, e.g., reducing death by psychiatric and somatic comorbidities, and will approach this goal by addressing interdisciplinary and cross-sector approaches across the lifespan. PriMe aims to add a precision medicine framework to the DZPG that will propel deeper understanding, more accurate prediction, and personalized prevention to prevent disease chronicity and mortality across mental illnesses. This framework is structured along the translational chain and will be used by PriMe to innovate the preventive and therapeutic management of SZ, BPD, and MDD from rural to urban areas and from patients in early disease stages to patients with long-term disease courses. Research will build on platforms that include one on model systems, one on the identification and validation of predictive markers, one on the development of novel multimodal treatments, one on the regulation and strengthening of the uptake and dissemination of personalized treatments, and finally one on testing of the clinical effectiveness, utility, and scalability of such personalized treatments. In accordance with the translational chain, PriMe’s expertise includes the ability to integrate understanding of bio-behavioral processes based on innovative models, to translate this knowledge into clinical practice and to promote user participation in mental health research and care

    Combining modeling tools to identify conservation priority areas: A case study of the last large-bodied avian frugivore in the Atlantic Forest

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    Applicability of modeling tools to tackle conservation problems is key for conservation planning. However, modeling papers regarding real-world conservation issues are scarce. Here, we combined two modeling tools to identify priority areas in the Brazilian Atlantic Forest, focusing on the last large-bodied frugivorous bird in the region, the red-billed curassow (Crax blumenbachii). We used population viability analysis (PVA) to determine (1) the minimum viable population size under different hunting scenarios; and (2) the minimum critical forest patch size required to maintain viable populations. We used ecological niche modeling (ENM) to identify remnants that retain suitable environmental conditions to ensure the long-term persistence of this species. We overlapped the outputs from PVA and ENM models to identify priority areas for curassows. Under our best-case scenario, 56 individuals would suffice to maintain a viable population and 71 forest patches located within the species' known range are above the critical size of 3141 ha. In the worst-case scenario, at least 138 individuals would be required to maintain a viable population in forest patches larger than 9500 ha, corresponding to only 20 Atlantic Forest fragments within the species range. Among these, 17 presented median habitat suitability values higher than 0.70, eight of which were selected as priority areas for law enforcement and nine as priority areas for reintroduction. We encourage conservation biologists and land managers to combine modeling tools which can be guided by our conservation planning framework. This approach is promising to inform long-term conservation planning of a flagship species and its entire ecosystem
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