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The rocky shores of the north-east Atlantic have been long studied. Our focus is from Gibraltar to Norway plus the Azores and Iceland. Phylogeographic processes shape biogeographic patterns of biodiversity. Long-term and broadscale studies have shown the responses of biota to past climate fluctuations and more recent anthropogenic climate change. Inter- and intra-specific species interactions along sharp local environmental gradients shape distributions and community structure and hence ecosystem functioning. Shifts in domination by fucoids in shelter to barnacles/mussels in exposure are mediated by grazing by patellid limpets. Further south fucoids become increasingly rare, with species disappearing or restricted to estuarine refuges, caused by greater desiccation and grazing pressure. Mesoscale processes influence bottom-up nutrient forcing and larval supply, hence affecting species abundance and distribution, and can be proximate factors setting range edges (e.g., the English Channel, the Iberian Peninsula). Impacts of invasive non-native species are reviewed. Knowledge gaps such as the work on rockpools and host–parasite dynamics are also outlined.
Cores from the bottom 4.83 m of the Antarctic ice sheet at Byrd Station contain abundant stratified debris ranging from silt-sized particles to cobbles. The nature and disposition of the debris, together with measurements of the physical properties of the inclosing ice, indicate that this zone of dirt-laden ice originated by “freezing-in” at the base of the ice sheet. The transition from air-rich glacial ice to ice practically devoid of air coincided precisely with the first appearance of debris in the ice at 4.83 m above the bed. Stable-isotope studies made in conjunction with gas-content measurements also confirm the idea of incorporation of basal debris by adfreezing of melt water at the ice―rock interface. It is suggested that the absence of air from basal ice may well constitute the most diagnostic test for discriminating between debris incorporated in a melt―refreeze process and debris entrapped by purely mechanical means, e.g. shearing. We conclude from our observations on bottom cores from Byrd Station that “freezing-in” of basal debris is the major mechanism by which sediment is incorporated into polar ice sheets.
Studies have demonstrated that the effects of two well-known predictors of adolescent substance use, family monitoring and antisocial peers, are not static but change over the course of adolescence. Moreover, these effects may differ for different groups of youth. The current study uses time-varying effect modeling to examine the changes in the association between family monitoring and antisocial peers and marijuana use from ages 11 to 19, and to compare these associations by gender and levels of behavioral disinhibition. Data are drawn from the Raising Healthy Children study, a longitudinal panel of 1,040 youth. The strength of association between family monitoring and antisocial peers and marijuana use was mostly steady over adolescence, and was greater for girls than for boys. Differences in the strength of the association were also evident by levels of behavioral disinhibition: youth with lower levels of disinhibition were more susceptible to the influence of parents and peers. Stronger influence of family monitoring on girls and less disinhibited youth was most evident in middle adolescence, whereas the stronger effect of antisocial peers was significant during middle and late adolescence. Implications for the timing and targeting of marijuana preventive interventions are discussed.
A 8x8 InSb CID array, developed in France by SAT (1) (Société Anonyme de Télécommunications) for terrestrial applications, has been tested at Meudon Observatory in order to evaluate if its performances at LHe temperature, meet the requirements of infrared astronomy. Next sections give : 1) Description of the array and the experimental conditions; 2) The test results; 3) Work under development.
Objectives: Although the clinical benefits of endovenous thermal ablation are widely recognized, few studies have evaluated the health economic implications of different treatments. This study compares 6-month clinical outcomes and cost-effectiveness of endovenous laser ablation (EVLA) compared with radiofrequency ablation (RFA) in the setting of a randomized clinical trial.
Methods: Patients with symptomatic primary varicose veins were randomized to EVLA or RFA and followed up for 6 months to evaluate clinical improvements, health related quality of life (HRQOL) and cost-effectiveness.
Results: A total of 131 patients were randomized, of which 110 attended 6-month follow-up (EVLA n = 54; RFA n = 56). Improvements in quality of life (AVVQ and SF-12v2) and Venous Clinical Severity Scores (VCSS) achieved at 6 weeks were maintained at 6 months, with no significant difference detected between treatment groups. There were no differences in treatment failure rates. There were small differences in favor of EVLA in terms of costs and 6-month HRQOL but these were not statistically significant. However, RFA is associated with less pain at up to 10 days.
Conclusions: EVLA and RFA result in comparable and significant gains in quality of life and clinical improvements at 6 months, compared with baseline values. EVLA is more likely to be cost-effective than RFA but absolute differences in costs and HRQOL are small.
To determine the impact of mucosal barrier injury laboratory-confirmed bloodstream infections (MBI-LCBIs) on central-line–associated bloodstream infection (CLABSI) rates during the first year of MBI-LCBI reporting to the National Healthcare Safety Network (NHSN)
Descriptive analysis of 2013 NHSN data
Selected inpatient locations in acute care hospitals
A descriptive analysis of MBI-LCBI cases was performed. CLABSI rates per 1,000 central-line days were calculated with and without the inclusion of MBI-LCBIs in the subset of locations reporting ≥1 MBI-LCBI, and in all locations (regardless of MBI-LCBI reporting) to determine rate differences overall and by location type.
From 418 locations in 252 acute care hospitals reporting ≥1 MBI-LCBIs, 3,162 CLABSIs were reported; 1,415 (44.7%) met the MBI-LCBI definition. Among these locations, removing MBI-LCBI from the CLABSI rate determination produced the greatest CLABSI rate decreases in oncology (49%) and ward locations (45%). Among all locations reporting CLABSI data, including those reporting no MBI-LCBIs, removing MBI-LCBI reduced rates by 8%. Here, the greatest decrease was in oncology locations (38% decrease); decreases in other locations ranged from 1.2% to 4.2%.
An understanding of the potential impact of removing MBI-LCBIs from CLABSI data is needed to accurately interpret CLABSI trends over time and to inform changes to state and federal reporting programs. Whereas the MBI-LCBI definition may have a large impact on CLABSI rates in locations where patients with certain clinical conditions are cared for, the impact of MBI-LCBIs on overall CLABSI rates across inpatient locations appears to be more modest.
Since hospitals in a region often share patients, an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) infection in one hospital could affect other hospitals.
Using extensive data collected from Orange County (OC), California, we developed a detailed agent-based model to represent patient movement among all OC hospitals. Experiments simulated MRSA outbreaks in various wards, institutions, and regions. Sensitivity analysis varied lengths of stay, intraward transmission coefficients (β), MRSA loss rate, probability of patient transfer or readmission, and time to readmission.
Each simulated outbreak eventually affected all of the hospitals in the network, with effects depending on the outbreak size and location. Increasing MRSA prevalence at a single hospital (from 5% to 15%) resulted in a 2.9% average increase in relative prevalence at all other hospitals (ranging from no effect to 46.4%). Single-hospital intensive care unit outbreaks (modeled increase from 5% to 15%) caused a 1.4% average relative increase in all other OC hospitals (ranging from no effect to 12.7%).
MRSA outbreaks may rarely be confined to a single hospital but instead may affect all of the hospitals in a region. This suggests that prevention and control strategies and policies should account for the interconnectedness of health care facilities.
This study aimed to describe the transmission dynamics, the serological and virus excretion patterns of Nipah virus (NiV) in Pteropus vampyrus bats. Bats in captivity were sampled every 7–21 days over a 1-year period. The data revealed five NiV serological patterns categorized as high and low positives, waning, decreasing and increasing, and negative in these individuals. The findings strongly suggest that NiV circulates in wild bat populations and that antibody could be maintained for long periods. The study also found that pup and juvenile bats from seropositive dams tested seropositive, indicating that maternal antibodies against NiV are transmitted passively, and in this study population may last up to 14 months. NiV was isolated from the urine of one bat, and within a few weeks, two other seronegative bats seroconverted. Based on the temporal cluster of seroconversion, we strongly believe that the NiV isolated was recrudesced and then transmitted horizontally between bats during the study period.
The La-Ba-Cu-O system contains several phases of special interest in the field of high Tc superconductivity. Specifically intriguing is the La3−xBa3+xCu6O4+y (“3–3–6”) phase [1,2], the La1·8 5Ba·1 5CuO4 (‘K2NiF4’) phase with a zero resistance temperature (Tc) of about 20 K [3,4], and the La1Ba2CU3O9–6 (“1–2–3”) phase with Tc's reported up to 75 K [5–7]. It has been suggested that the “3–3–6” phase may also be superconducting, especially in a Ba-doped version such that the stoichiometry is 2–4–6 [8–10]. In addition to defining a new high temperature superconducting phase, this latter suggestion would also rule out the possibility of Cu-0 “chains” being important to 90 K superconductivity since these chains are absent in the proposed configuration [1,2] of this phase.
Poly(o-toluidine) and poly(m-toluidine) in base form have been characterized by infrared and lH NMR spectroscopy. Assignments of the proton NMR signals have been facilitated by the use of model compounds. The distinction between benzenoid and quinoid methyl resonances in the NMR permits a semi-quantitative estimation of the oxidation states of the polytoluidines. Infrared studies are consistent with a polyaniline-type backbone having pendant methyl groups. Field desorption mass spectrometry (FD-MS) was employed for estimation of the molecular weight of poly(o-toluidine). Gel-permeation chromatography of the same sample showed a bimodal elution pattern, suggesting that the FD-MS technique detects only the lower molecular weight fraction of the polymer. Despite this inherent limitation, FD-MS yields the interesting information that the polymer contains chains of both odd and even numbers of repeat units, necessitating the coexistence of different oxidation states in the base form of the polymer.
We report optical, thermal, and transport studies on Kr+ implanted ladder (BBL) and rigid-rod ( PBO and PBZT) polymers, with an ion energy of 200 keV and dosage of 4 × 1016 / cm2. Both pristine and ion implanted polymers were studied using X-ray photo-electron spectroscopy (XPS), optical spectroscopy (IR and UV-Vis), thermogravimetric analysis (TGA), and temperature dependent DC conductivity (σ(T)). The XPS and IR results show a reduction in the heteroatoms and increase in the relative carbon content. After ion implantation, each polymer had a similar electronic structure, showing broad band metallic behavior. TGA data shows that each implanted polymer retains its thermal stability. σ(T) of the implanted polymers has the weakest temperature dependence of any conducting polymer reported, in accord with a disordered metal.
Recent advances in processing of polyaniline and polyacetylene have resulted in a new generation of conducting polymers with higher dc conductivities. We present the temperature (T) dependent microwave frequency dielectric constant, dc conductivity, and Kramers-Kronig analysis of conducting polyaniline and polyacetylene. The low temperature dielectric constant, ε, increases with the square of the x-ray crystalline domain length for preparations of HCl protonated polyaniline. For the highest crystalline polyaniline samples, ε increases dramatically with increasing T, supporting formation of three-dimensional (3-D) coupled “mesoscopic” Metallic regions. A “metallic” negative ε is observed for d,1-camphor sulfonie acid doped polyaniline prepared in m-cresol. Optical studies show a linear increase in reflectivity below 7000 cm-1. Below 600 cm-1 the reflectance increases rapidly. Kramers-Kronig analysis of the ir-visible results are presented. Highly conducting polyaniline is shown to have two plasma frequencies, one at ∼ 1.1 eV involving all the conduction band electrons, and one at ∼0.015 eV (120 cm-1) that is suggested to arise from the most delocalized electrons. The concept of inhomogeneous disorder is introduced. The results for polyaniline are compared to those of highly doped polyacetylene which also show metallic negative ε demonstrating the intrinsic metallic nature of the new generation of conducting polymers.
In the past decade a new class of magnets possessing spins on organic species have been discovered and studied. These magnets can be fabricated at room temperature and may enable useful devices and/or processes. Herein we discuss several of the mechanisms that can enable the stabilization of magnetic ordering and also provide examples of molecule-based magnets.
When thin films of polyaniline (emeraldine base, EB) are deposited on glass substrates from aqueous solutions of polymerizing aniline (“in-situ” EB-I film), they exhibit a Vis/UV spectrum in which the exciton peak has an absorption maximum at ∼600 nm; exposure to NMP vapor results in a shift of this peak to ∼650 nm (EB-II film). Doping of EBI film by aq. HCl gives the characteristic Vis/UV spectrum of “tight coil” doped polyaniline with a localized polaron peak at ∼820 nm. Treatment of EB-II film with HCl in a similar manner gives the characteristic spectrum of “expanded coil” doped polyaniline in which the ∼820 nm peak has disappeared and is replaced by a free carrier tail. It is concluded that EB-I and EB-II exist in “tight coil” and “expanded coil” molecular conformations respectively which do not change on doping in aqueous HCl.
We describe how the composition of an organic - based magnet can be controlled by varying the Chemical Vapor Deposition (CVD) conditions. A study was conducted for the Co2(CO)8/ TCNE system to form cobalt tetracyanoethylene [Co(TCNE)x, x∼2, a paramagnetic material], and for the V(CO)6/ TCNEx system to form vanadium tetracyanoethylene [V(TCNE)x, x∼2, a ferrimagnetic material]. Thin V(TCNE)x, x∼2 films (∼0.05-0.5 μm) with room temperature conductivity of 10-4<σRT<10-3S/cm and magnetic ordering temperature Tc of up to ∼400K were deposited. The V(TCNE)x, x∼2 thin films have the potential for incorporation in a spin-valve device as one of the magnetic contacts, and are promising candidates to form optically controlled magnetic-based structures.