Neutrino Oscillations in the Framework of Three-Generation Mixings with Mass Hierarchy

We have analyzed the results of reactor and accelerator neutrino oscillation experiments in the framework of a general model with mixing of three neutrino fields and a neutrino mass hierarchy that can accommodate the results of the solar neutrino experiments. It is shown that $\nu_\mu \leftrightarrows \nu_e$ oscillations with $0.6 \le \Delta m^2 \le 100 \, \mathrm{eV}^2$ and amplitude larger than $2 \times 10^{-3}$ are not compatible with the existing limits on neutrino oscillations if the non-diagonal elements of the mixing matrix $\left| U_{e3} \right|$ and $\left| U_{\mu3} \right|$ are small. Thus, if the excess of electron events recently observed in the LSND experiment is due to $\nu_\mu \leftrightarrows \nu_e$ oscillations, the mixing in the lepton sector is basically different from the CKM mixing of quarks. If this type of mixing is realized in nature, the observation of $\nu_\mu \leftrightarrows \nu_e$ oscillations would not influence $\nu_\mu \leftrightarrows \nu_\tau$ oscillations that are being searched for in the CHORUS and NOMAD experiments.Comment: Revtex file, 13 pages + 2 figures (included). The postscript file of text and figures is available at http://www.to.infn.it/teorici/giunti/papers.html or ftp://ftp.to.infn.it/pub/giunti/1995/dftt-25-95/dftt-25-95.ps.

Managing software development information in global configuration management activities

Software Configuration Management (SCM) techniques have been considered the entry point to rigorous software engineering, where multiple organizations cooperate in a decentralized mode to save resources, ensure the quality of the diversity of software products, and manage corporate information to get a better return of investment. The incessant trend of Global Software Development (GSD) and the complexity of implementing a correct SCM solution grow not only because of the changing circumstances, but also because of the interactions and the forces related to GSD activities. This paper addresses the role SCM plays in the development of commercial products and systems, and introduces a SCM reference model to describe the relationships between the different technical, organizational, and product concerns any software development company should support in the global market

Prognostic importance of plasma total magnesium in a cohort of cats with azotemic chronic kidney disease

BACKGROUND: Hypomagnesemia is associated with increased mortality and renal function decline in humans with chronic kidney disease (CKD). Magnesium is furthermore inversely associated with fibroblast growth factor 23 (FGF23), an important prognostic factor in CKD in cats. However, the prognostic significance of plasma magnesium in cats with CKD is unknown. OBJECTIVES: To explore associations of plasma total magnesium concentration (tMg) with plasma FGF23 concentration, all-cause mortality, and disease progression in cats with azotemic CKD. ANIMALS: Records of 174 client-owned cats with IRIS stage 2-4 CKD. METHODS: Cohort study. Cats with azotemic CKD were identified from the records of two London-based first opinion practices (1999-2013). Possible associations of baseline plasma tMg with FGF23 concentration and risks of death and progression were explored using, respectively, linear, Cox, and logistic regression. RESULTS: Plasma tMg (reference interval, 1.73-2.57 mg/dL) was inversely associated with plasma FGF23 when controlling for plasma creatinine and phosphate concentrations (partial correlation coefficient, -0.50; P < .001). Hypomagnesemia was observed in 12% (20/174) of cats, and independently associated with increased risk of death (adjusted hazard ratio, 2.74; 95% confidence interval [CI], 1.35-5.55; P = .005). The unadjusted associations of hypermagnesemia (prevalence, 6%; 11/174 cats) with survival (hazard ratio, 2.88; 95% CI, 1.54-5.38; P = .001), and hypomagnesemia with progressive CKD (odds ratio, 17.7; 95% CI, 2.04-154; P = .009) lost significance in multivariable analysis. CONCLUSIONS AND CLINICAL IMPORTANCE: Hypomagnesemia was associated with higher plasma FGF23 concentrations and increased risk of death. Measurement of plasma tMg augments prognostic information in cats with CKD, but whether these observations are associations or causations warrants further investigation

Maintaining dimensions and mechanical properties of ionically crosslinked alginate hydrogel scaffolds in vitro

Ionically crosslinked alginate hydrogels are attractive scaffolds because of their biocompatibility and mild gelation reaction that allows for gentle cell incorporation. However, the instability of ionically crosslinked hydrogels in an aqueous environment is a challenge that limits their application. This report presents a novel method to control the dimensions and mechanical properties of ionically crosslinked hydrogels via control of the ionic concentration of the medium. Homogeneous calcium-alginate gels were incubated in physiological saline baths adjusted to specific calcium ion concentrations. Swelling and shrinking occurred at low and high ionic concentrations of the medium, respectively, while an “optimal” intermediate calcium ion concentration of the medium was found to maintain original size and shape of the hydrogel. This optimal calcium ion concentration was found to be a function of crosslinking density and polymer concentration of the hydrogel and chemical composition of the alginate. The effects of optimal and high calcium ion concentrations of the medium on swelling behavior, calcium content, dry weight, and mechanical properties of the immersed hydrogels were investigated. It was found that the resulting hydrogel composition and mechanical properties depended on not only the calcium concentration of the medium, but also the crosslinking density and polymer concentration of the gel. In an 8-week experiment, controlled dimensions and mechanical properties of alginate gels in an aqueous environment were demonstrated. This new technique significantly enhances the potential of alginate hydrogels for tissue engineering and other biomedical applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58038/1/31375_ftp.pd

Membrane fouling, chemical cleaning and separation performance assessment of a chlorine-resistant nanofiltration membrane for water recycling applications

The effectiveness of hypochlorite cleaning for fouling mitigation of a prototype chlorine-resistant nanofiltration (NF) membrane was assessed for direct filtration of a secondary treated effluent. The chlorine resistance and separation performance of the prototype NF membrane were also compared to commercial NF and reverse osmosis membranes. The prototype chlorine resistant NF membrane did not show any changes in permeability and conductivity rejection after exposing a NaOCl solution for up to 5 × 104 ppm-h. By contrast, a considerable deterioration in rejection was observed for the other two commercial membranes. Direct filtration of a secondary treated effluent by the prototype NF membrane resulted in a progressive permeability reduction by up to 25% after 10 h of filtration. The membrane permeability was fully restored by hypochlorite cleaning with a 2000 ppm NaOCl solution for 1 h. Effective permeability recovery by hypochlorite cleaning was demonstrated with multiple hypochlorite cleaning cycles. Membrane fouling and hypochlorite cleaning were also simulated using solutions containing a model foulant (sodium alginate, humic acids or bovine serum albumin). Among them, an insufficient permeability recovery was observed for membrane fouling caused by humic acids. Further research is recommended to develop an improved hypochlorite cleaning protocol to control various membrane fouling

Postnatal nutrition environment reprograms renal DNA methylation patterns in offspring of maternal protein-restricted stroke-prone spontaneously hypertensive rats

Maternal malnutrition hampers the offspring health by manipulating the epigenome. Recent studies indicate that the changes in DNA methylation could be reversed by afterbirth nutrition supplementation. In this study, we used DNA methylation arrays to comprehensively investigate the DNA methylation status of the renal promoter regions and the effects of postnatal protein intake on DNA methylation. We fed stroke-prone spontaneously hypertensive (SHRSP) rat dams a normal diet or a low-protein diet during pregnancy, and their 4-week-old male offspring were fed a normal diet or a high−/low-protein diet for 2 weeks. We found that the methylation status of 2,395 differentially methylated DNA regions was reprogrammed, and 34 genes were reset by different levels of postnatal protein intake in the offspring. Among these genes, Adora2b, Trpc5, Ar, Xrcc2, and Atp1b1 are involved in renal disease and blood pressure regulation. Our findings indicate that postnatal nutritional interventions can potentially reprogram epigenetic changes, providing novel therapeutic and preventive epigenetic targets for salt-sensitive hypertension

The Growth of Massive Black Holes in Galaxy Merger Simulations with Feedback by Radiation Pressure

We study the growth of massive black holes (BH) in galaxies using smoothed particle hydrodynamic simulations of major galaxy mergers with new implementations of BH accretion and feedback. The effect of BH accretion on gas in its host galaxy is modeled by depositing momentum at a rate ~ tau L/c into the ambient gas, where L is the luminosity produced by accretion onto the BH and tau is the wavelength-averaged optical depth of the galactic nucleus to the AGN's radiation (a free parameter of our model). The accretion rate onto the BH is relatively independent of our subgrid accretion model and is instead determined by the BH's dynamical impact on its host galaxy: BH accretion is thus self-regulated rather than `supply limited.' We show that the final BH mass and total stellar mass formed during a merger are more robust predictions of the simulations than the time dependence of the star formation rate or BH accretion rate. In particular, the latter depend on the assumed interstellar medium physics, which determines when and where the gas fragments to form star clusters; this in turn affects the fuel available for further star formation and BH growth. Simulations over a factor of ~ 30 in galaxy mass are consistent with the observed M_BH-sigma relation for a mean optical depth of tau ~ 25. This requires that most BH growth occur when the galactic nucleus is optically thick to far-infrared radiation, consistent with the hypothesized connection between ultra-luminous infrared galaxies and quasars. We find tentative evidence for a shallower M_BH-sigma relation in the lowest mass galaxies, sigma < 100 km/s. Our results demonstrate that feedback-regulated BH growth and consistency with the observed M_BH-sigma relation do not require that BH feedback terminate star formation in massive galaxies or unbind large quantities of cold gas.Comment: 21 pages, 17 figures, submitted MNRA

Regional differences in APD restitution can initiate wavebreak and re-entry in cardiac tissue: A computational study

Background Regional differences in action potential duration (APD) restitution in the heart favour arrhythmias, but the mechanism is not well understood. Methods We simulated a 150 × 150 mm 2D sheet of cardiac ventricular tissue using a simplified computational model. We investigated wavebreak and re-entry initiated by an S1S2S3 stimulus protocol in tissue sheets with two regions, each with different APD restitution. The two regions had a different APD at short diastolic interval (DI), but similar APD at long DI. Simulations were performed twice; once with both regions having steep (slope > 1), and once with both regions having flat (slope < 1) APD restitution. Results Wavebreak and re-entry were readily initiated using the S1S2S3 protocol in tissue sheets with two regions having different APD restitution properties. Initiation occurred irrespective of whether the APD restitution slopes were steep or flat. With steep APD restitution, the range of S2S3 intervals resulting in wavebreak increased from 1 ms with S1S2 of 250 ms, to 75 ms (S1S2 180 ms). With flat APD restitution, the range of S2S3 intervals resulting in wavebreak increased from 1 ms (S1S2 250 ms), to 21 ms (S1S2 340 ms) and then 11 ms (S1S2 400 ms). Conclusion Regional differences in APD restitution are an arrhythmogenic substrate that can be concealed at normal heart rates. A premature stimulus produces regional differences in repolarisation, and a further premature stimulus can then result in wavebreak and initiate re-entry. This mechanism for initiating re-entry is independent of the steepness of the APD restitution curve

TopoWellPlate:A Well‐Plate‐Based Screening Platform to Study Cell–Surface Topography Interactions

The field of biomaterial engineering is increasingly using high‐throughput approaches to investigate cell–material interactions. Because most material libraries are prepared as chips, immunofluorescence‐based read‐outs are used to uniquely image individual materials. This paper proposes to produce libraries of materials using a well‐based strategy in which each material is physically separated, and thus compatible with standard biochemical assays. In this work, the TopoWellPlate, a novel system to study cell–surface topography interaction in high‐throughput is presented. From a larger library of topographies, 87 uniquely defined bioactive surface topographies are identified, which induce a wide variety of cellular morphologies. Topographically enhanced polystyrene films are fabricated in a multistep cleanroom process and served as base for the TopoWellPlate. Thermal bonding of the films to bottomless 96‐well plates results in a cell culture ready, topographically enhanced, 96‐well plate. The overall metabolic activity of bone marrow‐derived human mesenchymal stem cells is measured to show the functionality of the TopoWellPlate as a screening tool, which showed a 2.5‐fold difference range in metabolic activity per cell. TopoWellPlates of this and other topographical designs can be used to analyze cells using the wealth of standardized molecular assays available and thus disclose the mechanisms of biomaterials‐induced mechanotransduction