Stability of Relativistic Matter with Magnetic Fields for Nuclear Charges up to the Critical Value

We give a proof of stability of relativistic matter with magnetic fields all the way up to the critical value of the nuclear charge $Z\alpha=2/\pi$.Comment: LaTeX2e, 12 page

57Fe Mössbauer spectroscopy studies of chondritic meteorites from the Atacama Desert, Chile: Implications for weathering processes

Some terrestrial areas have climatic and geomorphologic features that favor the preservation, and therefore, accumulation of meteorites. The Atacama Desert in Chile is among the most important of such areas, known as dense collection areas. This desert is the driest on Earth, one of the most arid, uninhabitable locals with semi-arid, arid and hyper-arid conditions. The meteorites studied here were collected from within the dense collection area of San Juan at the Central Depression and Coastal Range of Atacama Desert. [superscript 57]Fe Mössbauer spectroscopy was used for quantitative analysis of the degree of weathering of the meteorites, through the determination of the proportions of the various Fe-bearing phases and in particular the amount of oxidized iron in the terrestrial alteration products. The abundance of ferric ions in weathered chondrites can be related to specific precursor compositions and to the level of terrestrial weathering. The aim of the study was the identification, quantification and differentiation of the weathering products in the ordinary chondrites found in the San Juan area of Atacama Desert

A surveillance system to monitor excess mortality of people with mental illness in Canada

Objective: Outcome measures are rarely available for surveillance and system performance monitoring for mental disorders and addictions. Our study aims to demonstrate the feasibility and face validity of routinely measuring the mortality gap in the Canadian context at the provincial and regional levels using the methods and data available to the Canadian Chronic Disease Surveillance System (CCDSS) of the Public Health Agency of Canada. Methods: We used longitudinal data from the Quebec Integrated Chronic Disease Surveillance System, which also provides aggregated data to the CCDSS. This includes data from the health insurance registry physician claims and the hospital discharge abstract for all mental disorder diagnoses (International Classification of Diseases [ICD]-9 290-319 or ICD-10 F00-F99). Patients were defined as having had received a mental disorder diagnosis at least once during the year. Life expectancy was measured using Chiang's method for abridged life tables, complemented by the Hsieh method for adjustment of the last age interval. Results: We found a lower life expectancy among psychiatric patients of 8 years for men and 5 years for women. For patients with schizophrenia, life expectancy was lowered by 12 years for men and 8 years for women. Cardiovascular disease and cancer were the most common causes of premature death. Findings were consistent across time and regions of the province. Lower estimates of the mortality gap, compared with literature, could be explained by the inclusion of primary care patients and methods. Conclusions: Our study demonstrates the feasibility of using administrative data to measure the impact of current and future mental health plans in Canada provided the techniques can be replicated in other Canadian provinces

Global Research Alliance N2O chamber methodology guidelines: Design considerations

Terrestrial ecosystems, both natural ecosystems and agroecosystems, generate greenhouse gases (GHGs). The chamber method is the most common method to quantify GHG fluxes from soil–plant systems and to better understand factors affecting their generation and mitigation. The objective of this study was to review and synthesize literature on chamber designs (non‐flow‐through, non‐steady‐state chamber) and associated factors that affect GHG nitrous oxide (N2O) flux measurement when using chamber methods. Chamber design requires consideration of many facets that include materials, insulation, sealing, venting, depth of placement, and the need to maintain plant growth and activity. Final designs should be tailored, and bench tested, in order to meet the nuances of the experimental objectives and the ecosystem under study while reducing potential artifacts. Good insulation, to prevent temperature fluctuations and pressure changes, and a high‐quality seal between base and chamber are essential. Elimination of pressure differentials between headspace and atmosphere through venting should be performed, and designs now exist to eliminate Venturi effects of earlier tube‐type vent designs. The use of fans within the chamber headspace increases measurement precision but may alter the flux. To establish best practice recommendations when using fans, further data are required, particularly in systems containing tall plants, to systematically evaluate the effects that fan speed, position, and mixing rate have on soil gas flux.Peer reviewe

Dynamic and combinatorial control of gene expression by nuclear retinoic acid receptors (RARs)

Nuclear retinoic acid receptors (RARs) are transcriptional regulators controlling the expression of specific subsets of genes in a ligand-dependent manner. The basic mechanism for switching on transcription of cognate target genes involves RAR binding at specific response elements and a network of interactions with coregulatory protein complexes, the assembly of which is directed by the C-terminal ligand-binding domain of RARs. In addition to this scenario, new roles for the N-terminal domain and the ubiquitin-proteasome system recently emerged. Moreover, the functions of RARs are not limited to the regulation of cognate target genes, as they can transrepress other gene pathways. Finally, RARs are also involved in nongenomic biological activities such as the activation of translation and of kinase cascades. Here we will review these mechanisms, focusing on how kinase signaling and the proteasome pathway cooperate to influence the dynamics of RAR transcriptional activity

Self-phase modulation-based integrated optical regeneration in chalcogenide waveguides

Copyright © 2006 IEEEWe demonstrate integrated all-optical 2R regenerators based on Kerr optical nonlinearities (subpicosecond response) in chalcogenide glass waveguides with integrated Bragg grating filters. By combining a low loss As₂S₃ rib waveguide with an in-waveguide photo-written Bragg grating filter, we realize an integrated all-optical 2R signal regenerator with the potential to process bit rates in excess of 1 Tb/s. The device operates using a combination of self phase modulation induced spectral broadening followed by a linear filter offset from the input centerwavelength.A nonlinear power transfer curve is demonstrated using 1.4 ps pulses, sufficient for suppressing noise in an amplified transmission link. We investigate the role of dispersion on the device transfer characteristics, and discuss future avenues to realizing a device capable of operation at subwatt peak power levels.Vahid G. Ta’eed, Mehrdad Shokooh-Saremi, Libin Fu, Ian C. M. Littler, David J. Moss, Martin Rochette, Benjamin J. Eggleton, Yinlan Ruan, and Barry Luther-Davie

Evaluating Elevated Convection with the Downdraft Convective Inhibition

A method for evaluating the penetration of a stable layer by an elevated convective downdraft is discussed. Some controversy exists on the community’s ability to define truly elevated convection from surface-based convection. By comparing the downdraft convective inhibition (DCIN) to the downdraft convective available potential energy (DCAPE), we determine that downdraft penetration potential is progressively enabled as the DCIN is progressively smaller than the DCAPE; inversely as DCIN increases over DCAPE, so does the likelihood of purely elevated convection. Serial vertical soundings and accompanying analyses are provided to support this finding

Linking forest cover, soil erosion and mire hydrology to late-Holocene human activity and climate in NW Spain

This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 3.0 License (http://www.creativecommons.org/licenses/by-nc/3.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (http://www.uk.sagepub.com/aboutus/openaccess.htm).This article has been made available through the Brunel Open Access Publishing Fund.Forest clearance is one of the main drivers of soil erosion and hydrological changes in mires, although climate may also play a significant role. Because of the wide range of factors involved, understanding these complex links requires long-term multi-proxy approaches and research on the best proxies to focus. A peat core from NW Spain (Cruz do Bocelo mire), spanning the last ~3000 years, has been studied at high resolution by physical (density and loss on ignition (LOI)), geochemical (elemental composition) and palynological (pollen and non-pollen palynomorphs) analyses. Proxies related to mineral matter fluxes from the catchment (lithogenic tracers, Glomus and Entorrhiza), rainfall (Bromine), mire hydrology (HdV-18), human pressure (Cerealia-type, nitrophilous taxa and coprophilous fungi) and forest cover (mesophilous tree taxa) were the most useful to reconstruct the evolution of the mire and its catchment. Forest clearance for farming was one of the main drivers of environmental change from at least the local Iron Age (~2685 cal. yr BP) onwards. The most intense phase of deforestation occurred during Roman and Germanic times and the late Middle Ages. During these phases, the entire catchment was affected, resulting in enhanced soil erosion and severe hydrological modifications of the mire. Climate, especially rainfall, may have also accelerated these processes during wetter periods. However, it is noteworthy that the hydrology of the mire seems to have been insensitive to rainfall variations when mesophilous forest dominated. Abrupt changes were only detected once intense forest clearance commenced during the Iron Age/Roman transition (~2190 cal. yr BP) phase, which represented a tipping point in catchment's ability to buffer impacts. Overall, our findings highlight the importance of studying ecosystems' long-term trajectories and catchment-wide processes when implementing mire habitat protection measures.This work was funded by the projects CGL2010-20672 (Plan Nacional I+D+i, Spanish Ministry of Science and Innovation) and 10PXIB200182PR (General Directorate of I+D, Xunta de Galicia). N Silva-Sánchez and L López-Merino are currently supported by a FPU predoctoral scholarship (AP2010-3264) funded by the Spanish Government and a MINT postdoctoral fellowship funded by the Brunel Institute for the Environment, respectively

Magnetic properties of tektites and other related impact glasses

© 2015 Elsevier B.V. We present a comprehensive overview of the magnetic properties of the four known tektite fields and related fully melted impact glasses (Aouelloul, Belize, Darwin, Libyan desert and Wabar glasses, irghizites, and atacamaites), namely magnetic susceptibility and hysteresis properties as well as properties dependent on magnetic grain-size. Tektites appear to be characterized by pure Fe2+ paramagnetism, with ferromagnetic traces below 1 ppm. The different tektite fields yield mostly non-overlapping narrow susceptibility ranges. Belize and Darwin glasses share similar characteristics. On the other hand the other studied glasses have wider susceptibility ranges, with median close to paramagnetism (Fe2+ and Fe3+) but with a high-susceptibility population bearing variable amounts of magnetite. This signs a fundamental difference between tektites (plus Belize and Darwin glasses) and other studied glasses in terms of oxygen fugacity and heterogeneity during formation, thus bringing new light to the formation processes of these materials. It also appears that selecting the most magnetic glass samples allows to find impactor-rich material, opening new perspectives to identify the type of impactor responsible for the glass generation