Diffusion of Ca and Mg in Calcite

The self-diffusion of Ca and the tracer diffusion of Mg in calcite have been experimentally measured using isotopic tracers of {sup 25}Mg and {sup 44}Ca. Natural single crystals of calcite were coated with a thermally-sputtered oxide thin film and then annealed in a CO{sub 2} gas at one atmosphere total pressure and temperatures from 550 to 800 C. Diffusion coefficient values were derived from the depth profiles obtained by ion microprobe analysis. The resultant activation energies for Mg tracer diffusion and Ca self-diffusion are respectively: E{sub a}(Mg) = 284 {+-} 74 kJ/mol and E{sub a}(Ca) = 271 {+-} 80 kJ/mol. For the temperature ranges in these experiments, the diffusion of Mg is faster than Ca. The results are generally consistent in magnitude with divalent cation diffusion rates obtained in previous studies and provide a means of interpreting the thermal histories of carbonate minerals, the mechanism of dolomitization, and other diffusion-controlled processes. The results indicate that cation diffusion in calcite is relatively slow and cations are the rate-limiting diffusing species for the deformation of calcite and carbonate rocks. Application of the calcite-dolomite geothermometer to metamorphic assemblages will be constrained by cation diffusion and cooling rates. The direct measurement of Mg tracer diffusion in calcite indicates that dolomitization is unlikely to be accomplished by Mg diffusion in the solid state but by a recrystallization process

STAMINA: Stochastic Approximate Model-Checker for Infinite-State Analysis

Stochastic model checking is a technique for analyzing systems that possess probabilistic characteristics. However, its scalability is limited as probabilistic models of real-world applications typically have very large or infinite state space. This paper presents a new infinite state CTMC model checker, STAMINA, with improved scalability. It uses a novel state space approximation method to reduce large and possibly infinite state CTMC models to finite state representations that are amenable to existing stochastic model checkers. It is integrated with a new property-guided state expansion approach that improves the analysis accuracy. Demonstration of the tool on several benchmark examples shows promising results in terms of analysis efficiency and accuracy compared with a state-of-the-art CTMC model checker that deploys a similar approximation method

Specification and Verification of Synchronous Hardware using LOTOS

This paper investigates specification and verification of synchronous circuits using DILL (Digital Logic in LOTOS). After an overview of the DILL approach, the paper focuses on the characteristics of synchronous circuits. A more constrained model is presented for specifying digital components and verifying them. Two standard benchmark circuits are specified using this new model, and analysed by the CADP toolset (Cæsar/Aldébaran Development Package)

Characteristics and risk factors associated with critical illness in pediatric COVID-19

© 2020, The Author(s). Background: While much has been reported regarding the clinical course of COVID-19 in children, little is known regarding factors associated with organ dysfunction in pediatric COVID-19. We describe critical illness in pediatric patients with active COVID-19 and identify factors associated with PICU admission and organ dysfunction. This is a retrospective chart review of 77 pediatric patients age 1 day to 21 years admitted to two New York City pediatric hospitals within the Northwell Health system between February 1 and April 24, 2020 with PCR + SARS-CoV-2. Descriptive statistics were used to describe the hospital course and laboratory results and bivariate comparisons were performed on variables to determine differences. Results: Forty-seven patients (61%) were admitted to the general pediatric floor and thirty (39%) to the PICU. The majority (97%, n = 75) survived to discharge, 1.3% (n = 1) remain admitted, and 1.3% (n = 1) died. Common indications for PICU admission included hypoxia (50%), hemodynamic instability (20%), diabetic ketoacidosis (6.7%), mediastinal mass (6.7%), apnea (6.7%), acute chest syndrome in sickle cell disease (6.7%), and cardiac dysfunction (6.7%). Of PICU patients, 46.7% experienced any significant organ dysfunction (pSOFA \u3e = 2) during admission. Patients aged 12 years or greater were more likely to be admitted to a PICU compared to younger patients (p = 0.015). Presence of an underlying comorbidity was not associated with need for PICU admission (p = 0.227) or organ dysfunction (p = 0.87). Initial white blood cell count (WBC), platelet count, and ferritin were not associated with need for PICU admission. Initial C-reactive protein was associated with both need for PICU admission (p = 0.005) and presence of organ dysfunction (p = 0.001). Initial WBC and presenting thrombocytopenia were associated with organ dysfunction (p = 0.034 and p = 0.003, respectively). Conclusions: Age over 12 years and initial CRP were associated with need for PICU admission in COVID-19. Organ dysfunction was associated with elevated admission CRP, elevated WBC, and thrombocytopenia. These factors may be useful in determining risk for critical illness and organ dysfunction in pediatric COVID-19

Efficacy of thalidomide in a girl with inflammatory calcinosis, a severe complication of juvenile dermatomyositis

We report a 14-year-old girl with juvenile dermatomyositis (JDM) complicated by severe inflammatory calcinosis successfully treated with thalidomide. She was diagnosed as JDM when she was 4 years old after a few months of increasing lethargy, muscle pain, muscle weakness, and rash. During three months, clinical manifestations and abnormal laboratory findings were effectively treated with oral prednisolone. However, calcinosis was recognized 18 months after disease onset. Generalized calcinosis rapidly progressed with high fever, multiple skin/subcutaneous inflammatory lesions, and increased level of CRP. Fifty mg/day (1.3 mg/kg day) of oral thalidomide was given for the first four weeks, and then the dose was increased to 75 mg/day. Clinical manifestations subsided, and inflammatory markers had clearly improved. Frequent high fever and local severe pain with calcinosis were suppressed. The levels of FDP-E, IgG, and tryglyceride, which were all elevated before the thalidomide treatment, were gradually returned to the normal range. Over the 18 months of observation up to the present, she has had no inflammatory calcinosis, or needed any hospitalization, although established calcium deposits still remain. Her condition became painless, less extensive and less inflammatory with the CRP level below 3.08 mg/dL. Recent examination by whole-body 18F-FDG-PET-CT over the 15 months of thalidomide treatment demonstrated fewer hot spots around the subcutaneous calcified lesions

Program Repair Suggestions from Graphical State-Transition Specifications

Abstract. In software engineering, graphical formalisms, like state-transition tables and automata, are very often indispensable parts of the specifications. Such a formalism usually leads to specification re-finement that maintains the simulation/bisimulation relation between an implementation and a specification. We investigate how to use formal techniques to generate suggestions for repairing a program that breaks the bisimulation relation with a graphical specification. We use state graphs as a unified representation of the program models and specifica-tions. We propose a technique that may evaluate the cost of a repair. We present a PTIME heuristic algorithm that suggests how to repair a model state graph. We then explain how to derive repair suggestions for programs from the repair for state graphs. Finally, we report our experi-ment that checks the performance of our repair algorithms and the costs of our repairs. Key words: state graph, state transition relation, repair, graph theory, cost, evaluation, equivalence, bisimulation

Safety of low-carbohydrate diets

Low-carbohydrate diets have re-emerged into the public spotlight and are enjoying a high degree of popularity as people search for a solution to the population\u27s ever-expanding waistline. The current evidence though indicates that low-carbohydrate diets present no significant advantage over more traditional energy-restricted diets on long-term weight loss and maintenance. Furthermore, a higher rate of adverse side-effects can be attributed to low-carbohydrate dieting approaches. Short-term efficacy of low-carbohydrate diets has been demonstrated for some lipid parameters of cardiovascular risk and measures of glucose control and insulin sensitivity, but no studies have ascertained if these effects represent a change in primary outcome measures. Low-carbohydrate diets are likely effective and not harmful in the short term and may have therapeutic benefits for weight-related chronic diseases although weight loss on such a program should be undertaken under medical supervision. While new commercial incarnations of the low-carbohydrate diet are now addressing overall dietary adequacy by encouraging plenty of high-fibre vegetables, fruit, low-glycaemic-index carbohydrates and healthier fat sources, this is not the message that reaches the entire public nor is it the type of diet adopted by many people outside of the world of a well-designed clinical trial. Health effects of long-term ad hoc restriction of inherently beneficial food groups without a concomitant reduction in body weight remains unanswered.<br /