High resolution carbon isotope stratigraphy of the basal Silurian stratotype (Dob's Linn, Scotland) and its global correlation

Since its designation as the Global Stratotype Section and Point (GSSP) for the base of the Silurian System, the choice of Dob's Linn, Southern Scotland, has received criticism due to the difficulties of relating its well constrained graptolite biostratigraphy to shallow water sequences elsewhere. Kerogen samples from across the Ordovician-Silurian boundary interval at Dob's Linn have yielded carbon stable isotope signatures consistent with those recorded elsewhere, in particular showing a clear positive δ13C excursion in the terminal Ordovician. The architecture of the δ13C curve from Dob's Linn enables very high resolution stratigraphic subdivision and direct correlation between the deep water Dob's Linn section and time equivalent carbonate shelf deposits. An integrated stratigraphic scheme using isotope stratigraphy and biostratigraphy of graptolites, conodonts and shelly faunas has been constructed. This direct correlation shows that the shallow water successions, including the former stratotype candidate at Anticosti Island, are generally incomplete, with hiatuses related to the rapid sea level changes during the Hirnantian stage. This confirms and greatly increases the global utility of Dob's Linn as a boundary stratotype

Siderite concretions from nonmarine shales (Westphalian A) of the Pennines, England: Controls on their growth and composition

Back-scattered electron microscopy has been used to examine the microstructure of nonmarine-shale-hosted siderite concretions. The concretions are composed of 50-100 mu m, zoned crystallites, which exhibit no noticeable center-to-edge variation within any individual concretion. This indicates that siderite crystallites nucleated at virtually the same time across the entire concretion and that the concretions did not grow by radial addition of siderite layers around a central nucleus. Further siderite precipitation took place by crystal growth onto the nuclei. The total proportion of siderite in any part of the concretion bears no simple relationship to the porosity of the enclosing shale at the time of precipitation, and growth by passive precipitation in pore space is unlikely. Integration of microprobe data with bulk mineral-chemical and stable-isotope data suggests that the siderite crystallites are composed of an Fe-Mn-rich end member with a delta(13)C value of similar to +10 parts per thousand and a Mg-Ca-rich end member with a delta(13)C value of similar to 0 parts per thousand to -5 parts per thousand. The mineral-chemical and stable-isotope compositions of these concretions resulted from microbially mediated processes operating close (< 10 m) to the sediment-water interface, during methanogenesis. Methanogenesis can generate low-delta(13)C as well as high-delta(13)C carbonate cements, hence deep-burial diagenetic reactions, such as decarboxylation of organic matter, need not be invoked to generate solutes for siderite precipitation

PHP152 How are topics selected and prioritized by the national institute of health and care excellence (nice) and what might be the options if a technology is not selected?

Contents: Safety culture assessment saves Barilla money via better understanding of employee attitudes; Iowa State and CIRAS launch new online safety training modules; CIRAS sets table for food companies\u27 success; CIRAS helps Regency Consulting rocket share of federal contracts upward 28 percent; Iowa\u27s worker shortage: An old problem requiring new solutions; Filling the pipeline: By growing your own workers; Luring labor via LEGOS; Timerbline\u27s long-term relationship with CIRAS enhances company growth an dprofitability; CIRAS-arragned webinar to show job shops how to get more done factor; Want to buy a rapid prototyping machine? Don\u27t decide too rapidlyhttps://lib.dr.iastate.edu/ciras_news/1048/thumbnail.jp

Current physical and mental health of former collegiate athletes

Background: There is a dearth of research on the current health of former collegiate athletes. Purpose: To examine the current health and related correlates in a cohort of former collegiate athletes who played in a diverse range of men’s and women’s sports with various levels of contact. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Former collegiate athletes (N = 3657) were asked to complete an online questionnaire addressing sports history, medical history, and demographics. The questionnaire also included the Veterans RAND 12-Item Health Survey (VR-12), which yielded 2 composite scores for physical (PCS) and mental (MCS) health. The VR-12 PCS and MCS scores were compared with published US normative data using t tests and analyses of variance. Results: Mean PCS and MCS scores of the 797 respondents with complete data (21.9% of target sample; average, 14.5 years since last played collegiate sport) were 53.0 ± 6.1 and 51.7 ± 9.4, respectively. When stratified by age and sex, PCS and MCS scores were similar to normative scores in the United States. Lower PCS scores were associated with sustaining ≤3 concussions, playing in collision sports during college, and sustaining a career-ending injury (all, P <.001). No association was found between concussion and MCS scores (P =.06). Among former collegiate athletes, prevalent medical conditions included anxiety (16.2%), hypercholesterolemia/high cholesterol (10.6%), and depression (10.4%). Additionally, 5.8% screened positive for alcohol dependence, and 5.8% screened positive for disordered eating (eg, binge eating, purging). These findings were more prevalent than those reported by the World Health Organization as representative of the US population. Conversely, there was a lower prevalence of depression, bipolar disorders, and attention deficit disorder, with or without hyperactivity (ADD/ADHD), than in the World Health Organization US population data sample. Conclusion: Former collegiate athletes appear similar to the general US population on many aspects of mental and physical health. However, observed health deficits associated with previous sports injuries warrant ongoing monitoring of the health and well-being of former collegiate athletes

A Simple Colorimetric Method for the Estimation of Relative Numbers of Lactobacilli in the Saliva

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67295/2/10.1177_00220345400190040101.pd

Blackbody Radiation and the Scaling Symmetry of Relativistic Classical Electron Theory with Classical Electromagnetic Zero-Point Radiation

It is pointed out that relativistic classical electron theory with classical electromagnetic zero-point radiation has a scaling symmetry which is suitable for understanding the equilibrium behavior of classical thermal radiation at a spectrum other than the Rayleigh-Jeans spectrum. In relativistic classical electron theory, the masses of the particles are the only scale-giving parameters associated with mechanics while the action-angle variables are scale invariant. The theory thus separates the interaction of the action variables of matter and radiation from the scale-giving parameters. Classical zero-point radiation is invariant under scattering by the charged particles of relativistic classical electron theory. The basic ideas of the matter -radiation interaction are illustrated in a simple relativistic classical electromagnetic example.Comment: 18 page

Extended wavelength mid-infrared photoluminescence from type-I InAsN and InGaAsN dilute nitride quantum wells grown on InP

Extended wavelength photoluminescence emission within the technologically important 2–5 micrometer spectral range has been demonstrated from InAs1xNx and In1yGayAs1xNx type I quantum wells grown onto InP. Samples containing N 1% and 2% exhibited 4K photoluminescence emission at 2.0 and 2.7 lm, respectively. The emission wavelength was extended out to 2.9 lm (3.3 lm at 300 K) using a metamorphic buffer layer to accommodate the lattice mismatch. The quantum wells were grown by molecular beam epitaxy and found to be of a high structural perfection as evidenced in the high resolution x-ray diffraction measurements. The photoluminescence was more intense from the quantum wells grown on the metamorphic buffer layer and persisted up to room temperature. The mid-infrared emission spectra were analysed, and the observed transitions were found to be in good agreement with the calculated emission energies