Winter Ecosystem Respiration and Sources of CO2 From the High Arctic Tundra of Svalbard: Response to a Deeper Snow Experiment

Currently, there is a lack of understanding on how the magnitude and sources of carbon (C) emissions from High Arctic tundra are impacted by changing snow cover duration and depth during winter. Here we investigated this issue in a graminoid tundra snow fence experiment on shale-derived gelisols in Svalbard from the end of the growing season and throughout the winter. To characterize emissions, we measured ecosystem respiration (Reco) along with its radiocarbon (14C) content. We assessed the composition of soil organic matter (SOM) by measuring its bulk-C and nitrogen (N), 14C content, and n-alkane composition. Our findings reveal that greater snow depth increased soil temperatures and winter Reco (25 mg C m−2 d−1 under deeper snow compared to 13 mg C m−2 d−1 in ambient conditions). At the end of the growing season, Reco was dominated by plant respiration and microbial decomposition of C fixed within the past 60 years (Δ14C = 62 ± 8‰). During winter, emissions were significantly older (Δ14C = −64 ± 14‰), and likely sourced from microorganisms decomposing aged SOM formed during the Holocene mixed with biotic or abiotic mineralization of the carbonaceous, fossil parent material. Our findings imply that snow cover duration and depth is a key control on soil temperatures and thus the magnitude of Reco in winter. We also show that in shallow Arctic soils, mineralization of carbonaceous parent materials can contribute significant proportions of fossil C to Reco. Therefore, permafrost-C inventories informing C emission projections must carefully distinguish between more vulnerable SOM from recently fixed biomass and more recalcitrant ancient sedimentary C sources

Removal of AMPA receptors (AMPARs) from synapses is preceded by transient endocytosis of extrasynaptic AMPARs

AMPA receptors (AMPARs) are dynamically regulated at synapses, but the time course and location of their exocytosis and endocytosis are not known. Therefore, we have used ecliptic pHluorin-tagged glutamate receptor 2 to visualize changes in AMPAR surface expression in real time. We show that synaptic and extrasynaptic AMPARs respond very differently to NMDA receptor activation; there is a rapid internalization of extrasynaptic AMPARs that precedes the delayed removal of synaptic AMPARs

Study of contamination sensors. Volume I - Executive summary report

Design criteria for automatic remotely indicating fluid contamination sensors, monitors, counters, and recorders and for sampling equipment and technique

Reasons for doctor migration from South Africa

Background: The migration of doctors from their home countries is not a new phenomenon. Apart from voluntary migration due to various reasons,medical professionals, often from sub-Saharan Africa, are actively recruited by developed countries. Doctors in South Africa are esteemed for the highstandard of training they receive locally, a quality which renders them prime candidates for employment. Various factors are involved in the push-pull theory of migration. It has, however, been reported extensively that push factors usually play a much greater role in doctors’ decision to leave their countries of origin, than do pull factors in the host or recipient country. Push factors motivating migration most frequently include dissatisfaction with remuneration packages and working conditions, high levels of crime and violence, political instability, lack of future prospects, HIV/AIDS and a decline in education systems. In addition to a depletion of intellectual resources through losing highly qualified and skilled  individuals, source countries also face substantial monetary implications caused by the migration of doctors. Government subsidy of medical students’ training could be regarded as a lost investment when young graduates seek permanent employment abroad. The aim of the study was to investigate the profile of South African qualified physicians who had emigrated from South Africa.Methods: The investigation was conducted in 2005 as a descriptive study of participants found primarily by the snowball sampling method. Theinitial participants were known to the researcher. Participants had to be graduates from South African medical schools/faculties, living abroad andin possession of a permanent work permit in the countries where they were employed. Short-term locum doctors were not included. Information,consent letters and questionnaires were either hand-delivered or e-mailed, and completed forms and questionnaires were returned via these routes.Participation was voluntary.Results: Twenty-nine of 43 potential participants responded, of which 79.3% were male and 20.7% female between the ages of 28 and 64 years(median 47 years). The year of graduation ranged from 1964 to 2000 (median 1985), and the year of leaving the country ranged from 1993 to 2005 (median 2002). The majority (72.4%) were in private practice before they left, 27.5% had public service appointments and 17.3% were employed by private hospitals. Seventy-nine per cent of respondents had postgraduate qualifications. Countries to which migration occurred included New Zealand, United Arab Emirates, Bahrain, United Kingdom, Canada, Yemen and Australia. Forty-one per cent of respondents indicated that they would encourage South African young people to study medicine, although 75% would recommend newly graduated doctors to leave the country. Financial factors were indicated as a reason for leaving by 86.2% of the respondents, better job opportunities by 79.3%, and the high crime rate in South Africa by 75.9%. Only 50% of the respondents said that better schooling opportunities for their children played a role in their decision to leave the country.Approximately one-fifth (17.9%) of the respondents indicated that they already had family abroad by the time they decided to emigrate.Conclusions: Financial reasons were the most important motivating factor in this particular group of doctors who relocated to overseas destinations,followed by working conditions and the rate of crime and violence in the country. In comparison to other investigations published previously, theresults presented here clearly indicate a tendency that more doctors offer financial and crime-related reasons for migration from South Africa thanbefore. In order to prevent the loss of medical expertise from a society already in need of quality healthcare, issues compelling doctors to look forgreener pastures should be addressed urgently and aggressively by stakeholders

Sclerites and possible mouthparts of Wiwaxia from the temperate palaeolatitudes of Colombia, South America

This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1111/let.12154The problematic mollusc Wiwaxia is perhaps the most widely distributed non-mineralized Cambrian metazoan, but has only been reported from palaeotropical latitudes. Here we describe mid Cambrian (Drumian, c. 504 Ma) sclerites and possible tooth arrays from the northern Llanos Basin, Colombia, recovered from drilled ditch cuttings by palynological processing – demonstrating that pristine material and low manipulation processing are not essential to the recovery of Small Carbonaceous Fossils. This, the first report of Wiwaxia from South America, substantially expands Wiwaxia’s geographic range into the high palaeolatitudes.We thank the two referees for their constructive comments, and Ecopetrol SA for permission to publish the wellbore material. Jean Bernard Caron, Peter Fenton, Doug Erwin and Mark Florence provided access to Burgess Shale material, which was funded in part by a Geological Society of America research grant to M.R.S. M.R.S. is supported by Clare College, Cambridge

Geochemical “fingerprints” for Olduvai Gorge Bed II tuffs and implications for the Oldowan–Acheulean transition

Bed II is a critical part of early Pleistocene Olduvai Gorge, Tanzania. Its deposits include transitions from humid to more arid conditions (with associated faunal changes), from Homo habilis to erectus, and from Oldowan to Acheulean technology. Bed II (~ 1.8–1.2 Ma) is stratigraphically and environmentally complex, with facies changes, faulting, and unconformities, making site-to-site correlation over the ~ 20 km of exposure difficult. Bed II tuffs are thinner, less evenly preserved, and more reworked than those of Bed I. Five marker tuffs (Tuffs IIA–IID, Bird Print Tuff (BPT)), plus local tephra, were collected from multiple sites and characterized using stratigraphic position, mineral assemblage, and electron probe microanalysis of phenocryst (feldspar, hornblende, augite, titanomagnetite) and glass (where available) composition. Lowermost Bed II tuffs are dominantly nephelinitic, Middle Bed II tuffs (BPT, Tuff IIC) have basaltic components, and upper Bed II Tuff IID is trachytic. The BPT and Tuff IID are identified widely using phenocryst compositions (high-Ca plagioclase and high-Ti hornblende, respectively), though IID was originally (Hay, 1976) misidentified as Tuff IIC at Loc 91 (SHK Annexe) in the Side Gorge. This work helps establish a high-resolution basin-wide paleolandscape context for the Oldowan–Acheulean transition and helps link hominin, faunal and archaeological records

Anisotropic Inflation from Extra Dimensions

Vacuum multidimensional cosmological models with internal spaces being compact $n$-dimensional Lie group manifolds are considered. Products of 3-spheres and $SU(3)$ manifold (a novelty in cosmology) are studied. It turns out that the dynamical evolution of the internal space drives an accelerated expansion of the external world (power law inflation). This generic solution (attractor in a phase space) is determined by the Lie group space without any fine tuning or arbitrary inflaton potentials. Matter in the four dimensions appears in the form of a number of scalar fields representing anisotropic scale factors for the internal space. Along the attractor solution the volume of the internal space grows logarithmically in time. This simple and natural model should be completed by mechanisms terminating the inflationary evolution and transforming the geometric scalar fields into ordinary particles.Comment: LaTeX, 11 pages, 5 figures available via fax on request to [email protected], submitted to Phys. Lett.

Tobacco Induced Priapism in Wister Rat: A Case Report

In an eight-week study on the effect of potash-tobacco dust ingestion on rats, a persistent penile erection for days was observed amongst some of the rats under study. This study involved a total of 42 Wister rats of weights rangingbetween 150-300g and grouped into four groups (A, B, C and D). Group A served as control, while groups B – Dserved as test groups and received 2g, 4g, and 6g of tobacco-dust, as well as 0.4g, 0.8g, and 1.2g of potash respectively, with water given ad libitum. By the 4th week, a persistent penile erection was observed in one of the rats in group C, and by the 6th week, a similar incident occurred in group C and D respectively, prompting serial observation. By the 8 week, gangrenous changes were observed, followed by necrosis and death of the rats on the 10th day from onset. The control rats (group A), which received normal feed and water, remained normal.Keywords: Priapism, Rat, Tobacco, Potash, Penile erectio

Shareholder Theory/Shareholder Value

Shareholder theory states that the primary objective of management is to maximize shareholder value. This objective ranks in front of the interests of other corporate stakeholders, such as employees, suppliers, customers, and society.Shareholder theory argues that shareholders are the ultimate owners of a corporate’s assets, and thus, the priority for managers and boards is to protect and grow these assets for the benefit of shareholders. Shareholder theory assumes that shareholders value corporate assets with two measurable metrics, dividends and share price. There-fore, management should make decisions that maximize the combined value of dividends and share price increases. However, shareholder theory fails to consider that shareholders and corporates may have other objectives that are not based on financial performance. For example, as early as1932, Berle and Means argued that corporations have a variety of purposes and interests including encouraging entrepreneurship, innovation, and building communities. This wider view is gaining more traction in recent decades as evidenced by an increased interest in ethical investment funds.This suggests that shareholders and potential shareholders are not only interested in financial gains but are also interested in corporates being socially responsible (Kyriakou2018). Therefore shareholder value creation is important; however,it needs to be balanced with other stakeholders’ interests. This is referred to as an enlightened approach to shareholder value maximization