A programming logic for Java bytecode programs

One significant disadvantage of interpreted bytecode languages, such as Java, is their low execution speed in comparison to compiled languages like C. The mobile nature of bytecode adds to the problem, as many checks are necessary to ensure that downloaded code from untrusted sources is rendered as safe as possible. But there do exist ways of speeding up such systems. One approach is to carry out static type checking at load time, as in the case of the Java Bytecode Verifier. This reduces the number of runtime checks that must be done and also allows certain instructions to be replaced by faster versions. Another approach is the use of a Just In Time (JIT) Compiler, which takes the bytecode and produces corresponding native code at runtime. Some JIT compilers also carry out some code optimization. There are, however, limits to the amount of optimization that can safely be done by the Verifier and JITs; some operations simply cannot be carried out safely without a certain amount of runtime checking. But what if it were possible to prove that the conditions the runtime checks guard against would never arise in a particular piece of code? In this case it might well be possible to dispense with these checks altogether, allowing optimizations not feasible at present. In addition to this, because of time constraints, current JIT compilers tend to produce acceptable code as quickly as possible, rather than producing the best code possible. By removing the burden of analysis from them it may be possible to change this. We demonstrate that it is possible to define a programming logic for bytecode programs that allows the proof of bytecode programs containing loops. The instructions available to use in the programs are currently limited, but the basis is in place to extend these. The development of this logic is non-trivial and addresses several difficult problems engendered by the unstructured nature of bytecode programs

Constitutive modeling for isotropic materials (HOST)

The results of the third year of work on a program which is part of the NASA Hot Section Technology program (HOST) are presented. The goals of this program are: (1) the development of unified constitutive models for rate dependent isotropic materials; and (2) the demonstration of the use of unified models in structural analyses of hot section components of gas turbine engines. The unified models selected for development and evaluation are those of Bodner-Partom and of Walker. A test procedure was developed for assisting the generation of a data base for the Bodner-Partom model using a relatively small number of specimens. This test procedure involved performing a tensile test at a temperature of interest that involves a succession of strain-rate changes. The results for B1900+Hf indicate that material constants related to hardening and thermal recovery can be obtained on the basis of such a procedure. Strain aging, thermal recovery, and unexpected material variations, however, preluded an accurate determination of the strain-rate sensitivity parameter is this exercise. The effects of casting grain size on the constitutive behavior of B1900+Hf were studied and no particular grain size effect was observed. A systematic procedure was also developed for determining the material constants in the Bodner-Partom model. Both the new test procedure and the method for determining material constants were applied to the alternate material, Mar-M247 . Test data including tensile, creep, cyclic and nonproportional biaxial (tension/torsion) loading were collected. Good correlations were obtained between the Bodner-Partom model and experiments. A literature survey was conducted to assess the effects of thermal history on the constitutive behavior of metals. Thermal history effects are expected to be present at temperature regimes where strain aging and change of microstructure are important. Possible modifications to the Bodner-Partom model to account for these effects are outlined. The use of a unified constitutive model for hot section component analyses was demonstrated by applying the Walker model and the MARC finite-element code to a B1900+Hf airfoil problem

Arginine-enriched oral nutritional supplementation in the treatment of pressure ulcers: A literature review

Abstract Purpose Pressure ulcers are a common, potentially mortal complication to disease, care and treatment for patients of all ages with mobility impairments. In addition, pressure ulcers not always heal straightforward because of multiple intrinsic factors e.g. undernutrition and extrinsic factors e.g. inadequate nutrition that may influence the healing process. The aim of this descriptive review is to investigate the treatment effect of arginine-enriched oral nutritional supplementation in pressure ulcers. Results The included studies, seven RCTs and four CTs, were published between January 2001 and October 2015, and conducted in different settings: hospital, long-term care/care homes and home care. The duration of follow-up of the studies varied from 2 weeks to complete healing and the sample size varied from 16 to 245 patients aged from 37 to 92 years and with pressure ulcer stages II, III or IV. The wound-specific oral nutritional supplementation contained 3–9 g of arginine. The main outcome measures were complete healing, time needed for complete wound closure, reduction in wound surface area, nursing time, and the number of dressings used. Ten out of eleven studies showed a beneficial effect of the arginine-enriched oral nutritional supplementation on the healing of pressure ulcers. Conclusions This review shows that there is substantial evidence supporting the positive effect of nutritional supplementation with additional protein, arginine and micronutrients to promote pressure ulcer healing. Currently, there is only one large study (N = 200) with level 1 evidence. It may be postulated that at least one extra comparable level 1 study is needed to draw firm conclusions on the importance of key nutrients in complete pressure ulcer healing

A Serological Biomarker of Laminin Gamma 1 Chain Degradation Reflects Altered Basement Membrane Remodeling in Crohn’s Disease and DSS Colitis

Background: The laminin gamma 1 chain (LMγ1) is abundant along the crypt-villus axis in the intestinal basement membrane. / Aims: We investigated whether a serological biomarker of laminin degradation was associated with disease activity in patients with Crohn’s disease (CD) and in rats with dextran sulfate sodium (DSS)-induced colitis. / Methods: Serum samples from CD patients (n = 43), healthy subjects (n = 19), and Sprague Dawley rats receiving 5–6% DSS water for five days and regular drinking water for 11 days were included in this study. The LG1M biomarker, a neo-epitope degradation fragment of the LMγ1 chain generated by matrix metalloproteinases-9 (MMP-9), was measured in serum to estimate the level of laminin degradation. / Results: Serum LG1M was elevated in CD patients with active and inactive disease compared to healthy subjects (p < 0.0001). LG1M distinguished CD patients from healthy subjects, with an area under the curve (AUC) of 0.81 (p < 0.0001). Serum LG1M was decreased in DSS rats compared to controls 2 days after DSS withdrawal, and increased upon reversal of the disease. / Conclusions: Increased serum LG1M in active and inactive CD patients supports the evidence of altered LM expression in both inflamed and non-inflamed tissue. Moreover, lower LG1M levels in the early healing phase of DSS-induced colitis may reflect ongoing mucosal repair

Euclid preparation : XVIII. The NISP photometric system

Euclid will be the first space mission to survey most of the extragalactic sky in the 0.95-2.02 mu m range, to a 5 sigma point-source median depth of 24.4 AB mag. This unique photometric dataset will find wide use beyond Euclid's core science. In this paper, we present accurate computations of the Euclid Y-E, J(E), and H-E passbands used by the Near-Infrared Spectrometer and Photometer (NISP), and the associated photometric system. We pay particular attention to passband variations in the field of view, accounting for, among other factors, spatially variable filter transmission and variations in the angle of incidence on the filter substrate using optical ray tracing. The response curves' cut-on and cut-off wavelengths - and their variation in the field of view - are determined with similar to 0.8 nm accuracy, essential for the photometric redshift accuracy required by Euclid. After computing the photometric zero points in the AB mag system, we present linear transformations from and to common ground-based near-infrared photometric systems, for normal stars, red and brown dwarfs, and galaxies separately. A Python tool to compute accurate magnitudes for arbitrary passbands and spectral energy distributions is provided. We discuss various factors, from space weathering to material outgassing, that may slowly alter Euclid's spectral response. At the absolute flux scale, the Euclid in-flight calibration program connects the NISP photometric system to Hubble Space Telescope spectrophotometric white dwarf standards; at the relative flux scale, the chromatic evolution of the response is tracked at the milli-mag level. In this way, we establish an accurate photometric system that is fully controlled throughout Euclid's lifetime.Peer reviewe

Elevated ectodomain of type 23 collagen is a novel biomarker of the intestinal epithelium to monitor disease activity in ulcerative colitis and Crohn's disease

BACKGROUND: Impaired intestinal epithelial barrier is highly affected in inflammatory bowel disease. Transmembrane collagens connecting the epithelial cells to the extracellular matrix have an important role in epithelial cell homeostasis. Thus, we sought to determine whether the transmembrane type 23 collagen could serve as a surrogate marker for disease activity in patients with Crohn's disease and ulcerative colitis. METHODS: We developed an enzyme-linked immunosorbent assay to detect the ectodomain of type 23 collagen (PRO-C23) in serum, followed by evaluation of its levels in both acute and chronic dextran sulfate sodium colitis models in rats and human inflammatory bowel disease cohorts. Serum from 44 Crohn's disease and 29 ulcerative colitis patients with active and inactive disease was included. RESULTS: In the acute and chronic dextran sulfate sodium-induced rat colitis model, the PRO-C23 serum levels were significantly increased after colitis and returned to normal levels after disease remission. Serum levels of PRO-C23 were elevated in Crohn's disease (p < 0.05) and ulcerative colitis (p < 0.001) patients with active disease compared to healthy donors. PRO-C23 differentiated healthy donors from ulcerative colitis (area under the curve: 0.81, p = 0.0009) and Crohn's disease (area under the curve: 0.70, p = 0.0124). PRO-C23 differentiated ulcerative colitis patients with active disease from those in remission (Area under the curve: 0.75, p = 0.0219) and Crohn's disease patients with active disease from those in remission (area under the curve: 0.68, p = 0.05). CONCLUSION: PRO-C23 was elevated in rats with active colitis, and inflammatory bowel disease patients with active disease. Therefore, PRO-C23 may be used as a surrogate marker for monitoring disease activity in ulcerative colitis and Crohn's disease

Euclid preparation : XIII. Forecasts for galaxy morphology with the Euclid Survey using deep generative models

We present a machine learning framework to simulate realistic galaxies for the Euclid Survey, producing more complex and realistic galaxies than the analytical simulations currently used in Euclid. The proposed method combines a control on galaxy shape parameters offered by analytic models with realistic surface brightness distributions learned from real Hubble Space Telescope observations by deep generative models. We simulate a galaxy field of 0.4x2006;deg(2) as it will be seen by the Euclid visible imager VIS, and we show that galaxy structural parameters are recovered to an accuracy similar to that for pure analytic Sersic profiles. Based on these simulations, we estimate that the Euclid Wide Survey (EWS) will be able to resolve the internal morphological structure of galaxies down to a surface brightness of 22.5x2006;magx2006;arcsec(-2), and the Euclid Deep Survey (EDS) down to 24.9x2006;magx2006;arcsec(-2). This corresponds to approximately 250 million galaxies at the end of the mission and a 50% complete sample for stellar masses above 10(10.6)M(circle dot) (resp. 10(9.6)M(circle dot)) at a redshift zx2004;similar to 0.5 for the EWS (resp. EDS). The approach presented in this work can contribute to improving the preparation of future high-precision cosmological imaging surveys by allowing simulations to incorporate more realistic galaxies.Peer reviewe

The time to extinction for an SIS-household-epidemic model

We analyse a stochastic SIS epidemic amongst a finite population partitioned into households. Since the population is finite, the epidemic will eventually go extinct, i.e., have no more infectives in the population. We study the effects of population size and within household transmission upon the time to extinction. This is done through two approximations. The first approximation is suitable for all levels of within household transmission and is based upon an Ornstein-Uhlenbeck process approximation for the diseases fluctuations about an endemic level relying on a large population. The second approximation is suitable for high levels of within household transmission and approximates the number of infectious households by a simple homogeneously mixing SIS model with the households replaced by individuals. The analysis, supported by a simulation study, shows that the mean time to extinction is minimized by moderate levels of within household transmission

Metabolism of ticagrelor in patients with acute coronary syndromes.

© The Author(s) 2018Ticagrelor is a state-of-the-art antiplatelet agent used for the treatment of patients with acute coronary syndromes (ACS). Unlike remaining oral P2Y12 receptor inhibitors ticagrelor does not require metabolic activation to exert its antiplatelet action. Still, ticagrelor is extensively metabolized by hepatic CYP3A enzymes, and AR-C124910XX is its only active metabolite. A post hoc analysis of patient-level (n = 117) pharmacokinetic data pooled from two prospective studies was performed to identify clinical characteristics affecting the degree of AR-C124910XX formation during the first six hours after 180 mg ticagrelor loading dose in the setting of ACS. Both linear and multiple regression analyses indicated that ACS patients presenting with ST-elevation myocardial infarction or suffering from diabetes mellitus are more likely to have decreased rate of ticagrelor metabolism during the acute phase of ACS. Administration of morphine during ACS was found to negatively influence transformation of ticagrelor into AR-C124910XX when assessed with linear regression analysis, but not with multiple regression analysis. On the other hand, smoking appears to increase the degree of ticagrelor transformation in ACS patients. Mechanisms underlying our findings and their clinical significance warrant further research.Peer reviewedFinal Published versio