Temperature dependence of absorption in photorefractive iron-doped lithium niobate crystals

We present experimental data showing a significant dependence of light absorption on temperature in photorefractive LiNbO3:Fe crystals. The results are successfully explained by assuming that the widths of the Fe2+ absorption bands in the visible and in the infrared spectral region depend on temperature. The findings are of relevance for thermal fixing of holograms. Furthermore, a temperature-induced increase of the infrared absorption is promising for improved infrared recording

Health Equity, Population Health, and Climate Change Adaptation in Ontario, Canada

Climate change holds the potential to exacerbate existing health inequalities, yet understanding how practitioners conceive health equity and health equality has received little attention in the scholarly literature. This contribution utilizes in-depth interviews with public health practitioners from health units across Ontario, Canada to characterize understandings of equity in relation to on-going climate change adaptation work. Perceptions of health equity and associated public health practices are described before discussing the resulting implications for how and why practitioners take up the equity agenda in relation to climate change. In doing so, this work problematizes existing public health tools and competencies and signals the emergence of new practices capable of simultaneously promoting adaptive capacity to climate change and reducing health inequity in Ontario

Infrastructure for the Coupling of Dune Grids

We describe an abstract interface for the geometric coupling of finite element grids. The scope of the interface encompasses a wide range of domain decomposition techniques in use today, including nonconforming grids and grids of different dimensions. The couplings are described as sets of remote intersections, which encapsulate the relationships between pairs of elements on the coupling interface. The abstract interface is realized in a module dune-grid-glue for the software framework dune. Several implementations of this interface exist, including one for general nonconforming couplings and a special efficient implementation for conforming interfaces. We present two numerical examples to show the flexibility of the approach

FLARE: Fingerprinting Deep Reinforcement Learning Agents using Universal Adversarial Masks

We propose FLARE, the first fingerprinting mechanism to verify whether a suspected Deep Reinforcement Learning (DRL) policy is an illegitimate copy of another (victim) policy. We first show that it is possible to find non-transferable, universal adversarial masks, i.e., perturbations, to generate adversarial examples that can successfully transfer from a victim policy to its modified versions but not to independently trained policies. FLARE employs these masks as fingerprints to verify the true ownership of stolen DRL policies by measuring an action agreement value over states perturbed via such masks. Our empirical evaluations show that FLARE is effective (100% action agreement on stolen copies) and does not falsely accuse independent policies (no false positives). FLARE is also robust to model modification attacks and cannot be easily evaded by more informed adversaries without negatively impacting agent performance. We also show that not all universal adversarial masks are suitable candidates for fingerprints due to the inherent characteristics of DRL policies. The spatio-temporal dynamics of DRL problems and sequential decision-making process make characterizing the decision boundary of DRL policies more difficult, as well as searching for universal masks that capture the geometry of it.Comment: Will appear in the proceedings of ACSAC 2023; 13 pages, 5 figures, 7 table

Poling effect on distribution of quenched random fields in a uniaxial relaxor ferroelectric

The frequency dependence of the dielectric permitivity's maximum has been studied for poled and unpoled doped relaxor strontium barium niobate $Sr_{0.61}Ba_{0.39}Nb_{2}O_{6}:Cr^{3+}$ (SBN-61:Cr). In both cases the maximum found is broad and the frequency dispersion is strong. The present view of random fields compensation in the unpoled sample is not suitable for explaining this experimental result. We propose a new mechanism where the dispersion of quenched random electric fields, affecting the nanodomains, is minimized after poling. We test our proposal by numerical simulations on a random field Ising model. Results obtained are in agreement with the polarization's measurements presented by Granzow et al. [Phys. Rev. Lett {\bf 92}, 065701 (2004)].Comment: 7 pages, 4 figure

Protective Role of Superoxide Dismutase against Diabetogenic Drugs

Copper-zinc superoxide dismutase (SOD) is present in relatively high concentrations in the β-cells of human islets. The activity of the extracted enzyme is partially inhibited upon incubation with the diabetogenic drugs alloxan, streptozotocin, or Vacor. The role of this enzyme in protecting β-cells against chemically induced diabetes was further investigated. Incubation of intact canine islets with alloxan (0.2 mg/ml) and 4 mM glucose decreased the insulin secretory response by 87% during subsequent exposure to 28 mM glucose. Concomitantly the SOD-specific activity (units of enzyme activity per milligram immunoreactive SOD) decreased 50% in alloxan-exposed islets. When islets were protected from alloxan toxicity by including 28 mM glucose with alloxan, the insulin secretory response and SOD specific activity remained identical to controls. Thus, SOD specific activity correlates with maintenance of β-cell function. To test the effectiveness of SOD against streptozotocin in vitro, canine islets were incubated 10 min with or without streptozotocin (0.1 mg/ml) with 4 mM glucose; their functional integrity was tested subsequently as the insulin secretory response to 28 mM glucose. Exposure to streptozotocin alone decreased the response by 70%; inclusion of SOD (1.5 mg/ml) before and during exposure to streptozotocin completely prevented this effect. Cyanide-inactivated SOD was not effective. The potential of SOD to prevent streptozotocin-induced diabetes was tested in rats in vivo. SOD injected 10 s or 50 min before streptozotocin prevented or significantly attenuated diabetes. Injection of SOD and streptozotocin simultaneously was much less effective, and cyanide-inactivated SOP was ineffective. No protection was afforded by injection of SOD 12 or 24 h before streptozotocin. Our results support hypotheses that (a) oxygen radicals mediate the β-cell toxicity of both alloxan and streptozotocin, and (b) β-cells may be particularly vulnerable to oxygen radical damage

Switching to Once-Daily Liraglutide From Twice-Daily Exenatide Further Improves Glycemic Control in Patients With Type 2 Diabetes Using Oral Agents

OBJECTIVETo evaluate efficacy and safety of switching from twice-daily exenatide to once-daily liraglutide or of 40 weeks of continuous liraglutide therapy.RESEARCH DESIGN AND METHODSWhen added to oral antidiabetes drugs in a 26-week randomized trial (Liraglutide Effect and Action in Diabetes [LEAD]-6), liraglutide more effectively improved A1C, fasting plasma glucose, and the homeostasis model of β-cell function (HOMA-B) than exenatide, with less persistent nausea and hypoglycemia. In this 14-week extension of LEAD-6, patients switched from 10 μg twice-daily exenatide to 1.8 mg once-daily liraglutide or continued liraglutide.RESULTSSwitching from exenatide to liraglutide further and significantly reduced A1C (0.32%), fasting plasma glucose (0.9 mmol/l), body weight (0.9 kg), and systolic blood pressure (3.8 mmHg) with minimal minor hypoglycemia (1.30 episodes/patient-year) or nausea (3.2%). Among patients continuing liraglutide, further significant decreases in body weight (0.4 kg) and systolic blood pressure (2.2 mmHg) occurred with 0.74 episodes/patient-year of minor hypoglycemia and 1.5% experiencing nausea.CONCLUSIONSConversion from exenatide to liraglutide is well tolerated and provides additional glycemic control and cardiometabolic benefits

Modulation of Rat Skeletal Muscle Branched-Chain α-Keto Acid Dehydrogenase In Vivo Effects of Dietary Protein and Meal Consumption

The effects of dietary protein on the activity of skeletal muscle branched-chain a-keto acid dehydrogenase (BCKAD) were investigated. BCKAD is rate-limiting for branched-chain amino acid (BCAA) catabolism by muscle; its activity is modulated by phosphorylation-dephosphorylation. In rats fed an adequate protein (25% casein) diet, BCKAD was - 2% active postabsorptively and increased to 10% or 16% active after a 25% or 50% protein meal, respectively. Prolonged feeding of a 50% protein diet increased postabsorptive BCKAD activity to 7% with further increases to 40% active postprandially. On a low protein (9% casein) diet BCKAD remained - 2% active regardless of meal-feeding. Dose-dependent activation of BCKAD by intravenous leucine in postabsorptive rats was blunted by a low protein diet. We conclude that excesses of dietary protein enhance the capacity of skeletal muscle to oxidize BCAA, muscle conserves BCAA when protein intake is inadequate, and skeletal muscle may play an important role in whole-body BCAA homeostasis

Выбор оптимальных технических решений для улавливания углеводородных паров от резервуарных парков нефти

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