1,689 research outputs found

    One-by-one trap activation in silicon nanowire transistors

    Full text link
    Flicker or 1/f noise in metal-oxide-semiconductor field-effect transistors (MOSFETs) has been identified as the main source of noise at low frequency. It often originates from an ensemble of a huge number of charges trapping and detrapping. However, a deviation from the well-known model of 1/f noise is observed for nanoscale MOSFETs and a new model is required. Here, we report the observation of one-by-one trap activation controlled by the gate voltage in a nanowire MOSFET and we propose a new low-frequency-noise theory for nanoscale FETs. We demonstrate that the Coulomb repulsion between electronically charged trap sites avoids the activation of several traps simultaneously. This effect induces a noise reduction by more than one order of magnitude. It decreases when increasing the electron density in the channel due to the electrical screening of traps. These findings are technologically useful for any FETs with a short and narrow channel.Comment: One file with paper and supplementary informatio

    Distributed and dynamic modelling of hydrology, phosphorus and ecology in the Hampshire Avon and Blashford Lakes: evaluating alternative strategies to meet WFD standards.

    Get PDF
    The issues of diffuse and point source phosphorus (P) pollution in the Hampshire Avon and Blashford Lakes are explored using a catchment model of the river system. A multibranch, process based, dynamic water quality model (INCA-P) has been applied to the whole river system to simulate water fluxes, total phosphorus (TP) and soluble reactive phosphorus (SRP) concentrations and ecology. The model has been used to assess impacts of both agricultural runoff and point sources from waste water treatment plants (WWTPs) on water quality. The results show that agriculture contributes approximately 40% of the phosphorus load and point sources the other 60% of the load in this catchment. A set of scenarios have been investigated to assess the impacts of alternative phosphorus reduction strategies and it is shown that a combined strategy of agricultural phosphorus reduction through either fertiliser reductions or better phosphorus management together with improved treatment at WWTPs would reduce the SRP concentrations in the river to acceptable levels to meet the EU Water Framework Directive (WFD) requirements. A seasonal strategy for WWTP phosphorus reductions would achieve significant benefits at reduced cost

    Three People Can Synchronize as Coupled Oscillators during Sports Activities

    Get PDF
    We experimentally investigated the synchronized patterns of three people during sports activities and found that the activity corresponded to spatiotemporal patterns in rings of coupled biological oscillators derived from symmetric Hopf bifurcation theory, which is based on group theory. This theory can provide catalogs of possible generic spatiotemporal patterns irrespective of their internal models. Instead, they are simply based on the geometrical symmetries of the systems. We predicted the synchronization patterns of rings of three coupled oscillators as trajectories on the phase plane. The interactions among three people during a 3 vs. 1 ball possession task were plotted on the phase plane. We then demonstrated that two patterns conformed to two of the three patterns predicted by the theory. One of these patterns was a rotation pattern (R) in which phase differences between adjacent oscillators were almost 2π/3. The other was a partial anti-phase pattern (PA) in which the two oscillators were anti-phase and the third oscillator frequency was dead. These results suggested that symmetric Hopf bifurcation theory could be used to understand synchronization phenomena among three people who communicate via perceptual information, not just physically connected systems such as slime molds, chemical reactions, and animal gaits. In addition, the skill level in human synchronization may play the role of the bifurcation parameter

    Bessel-Weighted Asymmetries in Semi Inclusive Deep Inelastic Scattering

    Get PDF
    The concept of weighted asymmetries is revisited for semi-inclusive deep inelastic scattering. We consider the cross section in Fourier space, conjugate to the outgoing hadron's transverse momentum, where convolutions of transverse momentum dependent parton distribution functions and fragmentation functions become simple products. Individual asymmetric terms in the cross section can be projected out by means of a generalized set of weights involving Bessel functions. Advantages of employing these Bessel weights are that they suppress (divergent) contributions from high transverse momentum and that soft factors cancel in (Bessel-) weighted asymmetries. Also, the resulting compact expressions immediately connect to previous work on evolution equations for transverse momentum dependent parton distribution and fragmentation functions and to quantities accessible in lattice QCD. Bessel weighted asymmetries are thus model independent observables that augment the description and our understanding of correlations of spin and momentum in nucleon structure.Comment: Matches published version, JHEP style, 36 pages and 2 figures, minor correction

    Oral chondroitin sulfate and prebiotics for the treatment of canine Inflammatory Bowel Disease: a randomized, controlled clinical trial

    Get PDF
    BACKGROUND Canine inflammatory bowel disease (IBD) is a chronic enteropathy of unknown etiology, although microbiome dysbiosis, genetic susceptibility, and dietary and/or environmental factors are hypothesized to be involved in its pathogenesis. Since some of the current therapies are associated with severe side effects, novel therapeutic modalities are needed. A new oral supplement for long-term management of canine IBD containing chondroitin sulfate (CS) and prebiotics (resistant starch, β-glucans and mannaoligosaccharides) was developed to target intestinal inflammation and oxidative stress, and restore normobiosis, without exhibiting any side effects. This double-blinded, randomized, placebo-controlled trial in dogs with IBD aims to evaluate the effects of 180 days administration of this supplement together with a hydrolyzed diet on clinical signs, intestinal histology, gut microbiota, and serum biomarkers of inflammation and oxidative stress. RESULTS Twenty-seven client-owned biopsy-confirmed IBD dogs were included in the study, switched to the same hydrolyzed diet and classified into one of two groups: supplement and placebo. Initially, there were no significant differences between groups (p > 0.05) for any of the studied parameters. Final data analysis (supplement: n = 9; placebo: n = 10) showed a significant decrease in canine IBD activity index (CIBDAI) score in both groups after treatment (p < 0.001). After treatment, a significant decrease (1.53-fold; p < 0.01) in histologic score was seen only in the supplement group. When groups were compared, the supplement group showed significantly higher serum cholesterol (p < 0.05) and paraoxonase-1 (PON1) levels after 60 days of treatment (p < 0.01), and the placebo group showed significantly reduced serum total antioxidant capacity (TAC) levels after 120 days (p < 0.05). No significant differences were found between groups at any time point for CIBDAI, WSAVA histologic score and fecal microbiota evaluated by PCR-restriction fragment length polymorphism (PCR-RFLP). No side effects were reported in any group. CONCLUSIONS The combined administration of the supplement with hydrolyzed diet over 180 days was safe and induced improvements in selected serum biomarkers, possibly suggesting a reduction in disease activity. This study was likely underpowered, therefore larger studies are warranted in order to demonstrate a supplemental effect to dietary treatment of this supplement on intestinal histology and CIBDAI

    Quantum Communication

    Get PDF
    Quantum communication, and indeed quantum information in general, has changed the way we think about quantum physics. In 1984 and 1991, the first protocol for quantum cryptography and the first application of quantum non-locality, respectively, attracted a diverse field of researchers in theoretical and experimental physics, mathematics and computer science. Since then we have seen a fundamental shift in how we understand information when it is encoded in quantum systems. We review the current state of research and future directions in this new field of science with special emphasis on quantum key distribution and quantum networks.Comment: Submitted version, 8 pg (2 cols) 5 fig

    Comparative mortality of hemodialysis patients at for-profit and not-for-profit dialysis facilities in the United States, 1998 to 2003: A retrospective analysis

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Concern lingers that dialysis therapy at for-profit (versus not-for-profit) hemodialysis facilities in the United States may be associated with higher mortality, even though 4 of every 5 contemporary dialysis patients receive therapy in such a setting.</p> <p>Methods</p> <p>Our primary objective was to compare the mortality hazards of patients initiating hemodialysis at for-profit and not-for-profit centers in the United States between 1998 and 2003. For-profit status of dialysis facilities was determined after subjects received 6 months of dialysis therapy, and mean follow-up was 1.7 years.</p> <p>Results</p> <p>Of the study population (<it>N </it>= 205,076), 79.9% were dialyzed in for-profit facilities after 6 months of dialysis therapy. Dialysis at for-profit facilities was associated with higher urea reduction ratios, hemoglobin levels (including levels above 12 and 13 g/dL [120 and 130 g/L]), epoetin doses, and use of intravenous iron, and less use of blood transfusions and lower proportions of patients on the transplant waiting-list (<it>P </it>< 0.05). Patients dialyzed at for-profit and at not-for-profit facilities had similar mortality risks (adjusted hazards ratio 1.02, 95% CI 0.99–1.06, <it>P </it>= 0.143).</p> <p>Conclusion</p> <p>While hemodialysis treatment at for-profit and not-for-profit dialysis facilities is associated with different patterns of clinical benchmark achievement, mortality rates are similar.</p

    Risk Factors for Prognosis in Patients With Severely Decreased GFR

    Get PDF
    Introduction: Patients with chronic kidney disease (CKD) and estimated glomerular filtration rate (eGFR) < 30 ml/min per 1.73 m 2 (corresponding to CKD stage G4+) comprise a minority of the overall CKD population but have the highest risk for adverse outcomes. Many CKD G4+ patients are older with multiple comorbidities, which may distort associations between risk factors and clinical outcomes. Methods: We undertook a meta-analysis of risk factors for kidney failure treated with kidney replacement therapy (KRT), cardiovascular disease (CVD) events, and death in participants with CKD G4+ from 28 cohorts (n = 185,024) across the world who were part of the CKD Prognosis Consortium. Results: In the fully adjusted meta-analysis, risk factors associated with KRT were time-varying CVD, male sex, black race, diabetes, lower eGFR, and higher albuminuria and systolic blood pressure. Age was associated with a lower risk of KRT (adjusted hazard ratio: 0.74; 95% confidence interval: 0.69–0.80) overall, and also in the subgroup of individuals younger than 65 years. The risk factors for CVD events included male sex, history of CVD, diabetes, lower eGFR, higher albuminuria, and the onset of KRT. Systolic blood pressure showed a U-shaped association with CVD events. Risk factors for mortality were similar to those for CVD events but also included smoking. Most risk factors had qualitatively consistent associations across cohorts. Conclusion: Traditional CVD risk factors are of prognostic value in individuals with an eGFR < 30 ml/min per 1.73 m 2, although the risk estimates vary for kidney and CVD outcomes. These results should encourage interventional studies on correcting risk factors in this high-risk population

    Population dynamics of a pathogen: the conundrum of vivax malaria

    Get PDF
    Building a mathematical model of population dynamics of pathogens within their host involves considerations of factors similar to those in ecology, as pathogens can prey on cells in the host. But within the multicellular host, attacked cell types are integrated with other cellular systems, which in turn intervene in the infection. For example, immune responses attempt to sense and then eliminate or contain pathogens, and homeostatic mechanisms try to compensate for cell loss. This review focuses on modeling applied to malarias, diseases caused by single-cell eukaryote parasites that infect red blood cells, with special concern given to vivax malaria, a disease often thought to be benign (if sometimes incapacitating) because the parasite only attacks a small proportion of red blood cells, the very youngest ones. However, I will use mathematical modeling to argue that depletion of this pool of red blood cells can be disastrous to the host if growth of the parasite is not vigorously check by host immune responses. Also, modeling can elucidate aspects of new field observations that indicate that vivax malaria is more dangerous than previously thought
    corecore