Power law in a gauge-invariant cut-off regularisation

We study one-loop quantum corrections of a compactified Abelian 5d gauge field theory. We use a cut-off regularisation procedure which respects the symmetries of the model, i.e. gauge invariance, exhibits the expected power-like divergences and therefore allows the derivation of power-law behavior of the effective 4d gauge coupling in a coherent manner.Comment: 5 pages, 1 figure, 5 graphs, few references added, to appear in Phys.Rev. Rapid Communication

The R Package metaLik for Likelihood Inference in Meta-Analysis

Meta-analysis is a statistical method for combining information from different studies about the same issue of interest. Meta-analysis is widely diffuse in medical investigation and more recently it received a growing interest also in social disciplines. Typical applications involve a small number of studies, thus making ordinary inferential methods based on first-order asymptotics unreliable. More accurate results can be obtained by exploiting the theory of higher-order asymptotics. This paper describes the metaLik package which provides an R implementation of higher-order likelihood methods in meta-analysis. The extension to meta-regression is included. Two real data examples are used to illustrate the capabilities of the package

The Effects of Additives on the Dehydrogenation of Amorphous Manganese Borohydride and Its Crystalline Form after Solvent Filtration/Extraction

A non-stoichiometric, amorphous a-Mn(BH4)(2x) hydride, accompanied by a NaCl-type salt, was mechanochemically synthesized from the additive-free mixture of (2NaBH4 + MnCl2), as well as from the mixtures containing the additives of ultrafine filamentary carbonyl nickel (Ni), graphene, and LiNH2. It is shown that both graphene and LiNH2 suppressed the release of B2H6 during thermal gas desorption, with the LiNH2 additive being the most effective suppressor of B2H6. During solvent filtration and extraction of additive-free, as well as additive-bearing, (Ni and graphene) samples from diethyl ether (Et2O), the amorphous a-Mn(BH4)(2x) hydride transformed into a crystalline c-Mn(BH4)2 hydride, exhibiting a microstructure containing nanosized crystallites (grains). In contrast, the LiNH2 additive most likely suppressed the formation of a crystalline c-Mn(BH4)2 hydride during solvent filtration/extraction. In a differential scanning calorimeter (DSC), the thermal decomposition peaks of both amorphous a-Mn(BH4)(2x) and crystalline c-Mn(BH4)2 were endothermic for the additive-free samples, as well as the samples with added graphene and Ni. The samples with LiNH2 exhibited an exothermic DSC decomposition peak.Natural Sciences and Engineering Research Council (NSERC) of Canada Discovery gran

Mechano-chemical synthesis of nanostructured hydride composites based on Li-Al-N-Mg for solid state hydrogen storage

It is observed that large quantities of hydrogen (H2) are released at ambient temperatures during the mechano-chemical synthesis of the Li-Al-N-Mg-based hydride composites using an energetic ball milling in a unique magneto-mill. For the (nLiAlH4+LiNH2; n=1, 3, 11.5, 30) composite, at the molar ratio n=1, the LiNH2 constituent destabilizes LiAlH4 and enhances its decomposition to Li3AlH6, Al and H2, and subsequently Li3AlH6 to LiH, Al and H2. LiNH2 ceases to destabilize LiAlH4 in the composites with increasing molar content of LiAlH4 (n≥3). For the (nLiAlH4+MnCl2; n=1, 3, 8, 13, 30, 63) composite, XRD phase analysis shows that chemical reaction occurs during ball milling between the hydride and chloride constituent forming either an inverse cubic spinel Li2MnCl4 for n=1 or lithium salt (LiCl) for n>1. Both reactions release hydrogen. For the (LiNH2+nMgH2; n=1, 1.5) composite the pathway of hydride reactions depends on the milling energy and milling time. Under low milling energy up to 25h there is either no reaction (1h) or the reaction products are amorphous Mg(NH2)2 (magnesium amide) and nanocrystalline LiH (lithium hydride) without any release of hydrogen. Under high milling energy a new hydride MgNH (magnesium imide) is formed due to reaction between Mg(NH2)2 and MgH2 which is always associated with the release of H2

Directed precipitation of anhydrous magnesite for improved performance of mineral carbonation of CO2

The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.jece.2017.06.048 © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/This paper studies the indirect aqueous carbon sequestration via Mg(OH)2 using directed precipitation technique. This technique produces anhydrous MgCO3 (magnesite), the most desirable carbonated phase for sequestration. The formation of magnesite is significantly affected by its kinetics of precipitation in an aqueous carbonation medium. This study considers directed precipitation strategy to control precipitation of anhydrous magnesite through enhancement of the heterogeneous precipitation. Heterogeneous precipitation is implemented using seeding material that could improve the conversion efficiency of the directed carbonation of Mg(OH)2. A ternary phase diagram is achieved which represents the relative concentration of possible precipitated phases: brucite (Mg(OH)2), magnesite and hydromagnesit (Mg5(CO3)4(OH)2·4H2O). The results reveal the fundamental role of heterogeneous precipitation on the magnesite concentration and conversion percentage of Mg(OH)2 wet carbonation process. Two seeding materials, hydrophobic activated carbon and hydrophilic alumina, were tested and the influence of the surface chemistry of varying seeding sites (hydrophobic vs. hydrophilic seeds) was elaborated. At the carbonation temperature of 100°C and 150°C, a heterogeneous precipitation using hydrophilic alumina results in lower concentrations of anhydrous magnesite in precipitated compounds, even as compared to the seedless solution, owing to the hydrophilic properties of alumina. In contrast, use of activated carbon as heterogeneous nucleation sites in an aqueous medium results in a magnesite concentration of around 60% and the corresponding carbonation conversion of about 72% under the controlled condition of 200°C and 30bar CO2 pressure.Network of Centres of Excellence - Carbon Management Canada (CMC)Natural Sciences and Engineering Research Council of Canada (NSERC)Waterloo Institute for Nanotechnology (WIN

Hybrid copula mixed models for combining case-control and cohort studies in meta-analysis of diagnostic tests

Copula mixed models for trivariate (or bivariate) meta-analysis of diagnostic test accuracy studies accounting (or not) for disease prevalence have been proposed in the biostatistics literature to synthesize information. However, many systematic reviews often include case-control and cohort studies, so one can either focus on the bivariate meta-analysis of the case-control studies or the trivariate meta-analysis of the cohort studies, as only the latter contains information on disease prevalence. In order to remedy this situation of wasting data we propose a hybrid copula mixed model via a combination of the bivariate and trivariate copula mixed model for the data from the case-control studies and cohort studies, respectively. Hence, this hybrid model can account for study design and also due to its generality can deal with dependence in the joint tails. We apply the proposed hybrid copula mixed model to a review of the performance of contemporary diagnostic imaging modalities for detecting metastases in patients with melanoma

On composite likelihood in bivariate meta-analysis of diagnostic test accuracy studies

The composite likelihood (CL) is amongst the computational methods used for estimation of the generalized linear mixed model (GLMM) in the context of bivariate meta-analysis of diagnostic test accuracy studies. Its advantage is that the likelihood can be derived conveniently under the assumption of independence between the random effects, but there has not been a clear analysis of the merit or necessity of this method. For synthesis of diagnostic test accuracy studies, a copula mixed model has been proposed in the biostatistics literature. This general model includes the GLMM as a special case and can also allow for flexible dependence modelling, different from assuming simple linear correlation structures, normality and tail independence in the joint tails. A maximum likelihood (ML) method, which is based on evaluating the bi-dimensional integrals of the likelihood with quadrature methods has been proposed, and in fact it eases any computational difficulty that might be caused by the double integral in the likelihood function. Both methods are thoroughly examined with extensive simulations and illustrated with data of a published meta-analysis. It is shown that the ML method has non-convergence issues or computational difficulties and at the same time allows estimation of the dependence between study-specific sensitivity and specificity and thus prediction via summary receiver operating curves

Iron speciation in aerosol dust influences iron bioavailability over glacial-interglacial timescales

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To the problem of doctor’s tactics in patients with pleuritis of uncertain genesis

Polyetiologic features of pleuritis lesions, doctors' particular speciality and the lack of standards give rise to inevitable difficulties in making diagnosis, while the introduction of modern research innovations solves only specific problems. All above mentioned issues require the introduction of new organizational technologies. Retrospective analysis of medical records of 968 patients performed at the centre of the Novokuznetsk State Clinical Tuberculous Hospital showed the efficacy of algorithm usage in specialized medical care and doctor's tactics. In 91% of patients the period for diagnosis verification was 10,4+2,0 days, and idiopathic pleuritis shared 4% of patients.Полиэтиологичность поражений плевры, узкая специализация врачей и отсутствие стандартов порождают неизбежные трудности диагностики, а внедрение наукоемких исследований решает лишь частные проблемы. Необходим пересмотр ситуации, использование новых организационных технологий. Данные ретроспективного анализа историй болезни 968 пациентов плеврального центра при ГУЗ «НКТБ», показали эффективность специализированной помощи и врачебной тактики, формализованной в виде алгоритма. Для 91% больных время верификации диагноза в среднем составляет 10,4+2,0 дней, а доля идиопатических плевритов — 4%

Variability in black carbon mass concentration in surface snow at Svalbard

Black carbon (BC) is a significant forcing agent in the Arctic, but substantial uncertainty remains to quantify its climate effects due to the complexity of the different mechanisms involved, in particular related to processes in the snowpack after deposition. In this study, we provide detailed and unique information on the evolution and variability in BC content in the upper surface snow layer during the spring period in Svalbard (Ny-Ålesund). A total of two different snow-sampling strategies were adopted during spring 2014 (from 1 April to 24 June) and during a specific period in 2015 (28 April to 1 May), providing the refractory BC (rBC) mass concentration variability on a seasonal variability with a daily resolution (hereafter seasonal/daily) and daily variability with an hourly sampling resolution (hereafter daily/hourly) timescales. The present work aims to identify which atmospheric variables could interact with and modify the mass concentration of BC in the upper snowpack, which is the snow layer where BC particles affects the snow albedo. Atmospheric, meteorological and snow-related physico-chemical parameters were considered in a multiple linear regression model to identify the factors that could explain the variations in BC mass concentrations during the observation period. Precipitation events were the main drivers of the BC variability during the seasonal experiment; however, in the high-resolution sampling, a negative association has been found. Snow metamorphism and the activation of local sources (Ny-Ålesund was a coal mine settlement) during the snowmelt periods appeared to play a non-negligible role. The statistical analysis suggests that the BC content in the snow is not directly associated to the atmospheric BC load