Non-Fermi liquid behavior of SrRuO_3 -- evidence from infrared conductivity

The reflectivity of the itinerant ferromagnet SrRuO_3 has been measured between 50 and 25,000 cm-1 at temperatures ranging from 40 to 300 K, and used to obtain conductivity, scattering rate, and effective mass as a function of frequency and temperature. We find that at low temperatures the conductivity falls unusually slowly as a function of frequency (proportional to \omega^{-1/2}), and at high temperatures it even appears to increase as a function of frequency in the far-infrared limit. The data suggest that the charge dynamics of SrRuO_3 are substantially different from those of Fermi-liquid metals.Comment: 4 pages, 3 postscript figure

Nanosecond Transient IR Spectroscopy of Halorhodopsin in Living Cells

The ability to track minute changes of a single amino acid residue in a cellular environment is causing a paradigm shift in the attempt to fully understand the responses of biomolecules that are highly sensitive to their environment. Detecting early protein dynamics in living cells is crucial to understanding their mechanisms, such as those of photosynthetic proteins. Here, we elucidate the light response of the microbial chloride pump NmHR from the marine bacterium Nonlabens marinus, located in the membrane of living Escherichia coli cells, using nanosecond time-resolved UV/vis and IR absorption spectroscopy over the time range from nanoseconds to seconds. Transient structural changes of the retinal cofactor and the surrounding apoprotein are recorded using light-induced time-resolved UV/vis and IR difference spectroscopy. Of particular note, we have resolved the kinetics of the transient deprotonation of a single cysteine residue during the photocycle of NmHR out of the manifold of molecular vibrations of the cells. These findings are of high general relevance, given the successful development of optogenetic tools from photoreceptors to interfere with enzymatic and neuronal pathways in living organisms using light pulses as a noninvasive trigger

The Photoreaction of the Proton-Pumping Rhodopsin 1 From the Maize Pathogenic Basidiomycete Ustilago maydis

Microbial rhodopsins have recently been discovered in pathogenic fungi and have been postulated to be involved in signaling during the course of an infection. Here, we report on the spectroscopic characterization of a light-driven proton pump rhodopsin (UmRh1) from the smut pathogen Ustilago maydis, the causative agent of tumors in maize plants. Electrophysiology, time-resolved UV/Vis and vibrational spectroscopy indicate a pH-dependent photocycle. We also characterized the impact of the auxin hormone indole-3-acetic acid that was shown to influence the pump activity of UmRh1 on individual photocycle intermediates. A facile pumping activity test was established of UmRh1 expressed in Pichia pastoris cells, for probing proton pumping out of the living yeast cells during illumination. We show similarities and distinct differences to the well-known bacteriorhodopsin from archaea and discuss the putative role of UmRh1 in pathogenesis

Do Doctors Vote?

BACKGROUND: Organizational leaders and scholars have issued calls for the medical profession to refocus its efforts on fulfilling the core tenets of professionalism. A key element of professionalism is participation in community affairs. OBJECTIVE: To measure physician voting rates as an indicator of civic participation. DESIGN: Cross-sectional survey of a subgroup of physicians from a nationally representative household survey of civilian, noninstitutionalized adult citizens. PARTICIPANTS: A total of 350,870 participants in the Current Population Survey (CPS) November Voter Supplement from 1996–2002, including 1,274 physicians and 1,886 lawyers; 414,989 participants in the CPS survey from 1976–1982, including 2,033 health professionals. MEASUREMENTS: Multivariate logistic regression models were used to compare adjusted physician voting rates in the 1996–2002 congressional and presidential elections with those of lawyers and the general population and to compare voting rates of health professionals in 1996–2002 with those in 1976–1992. RESULTS: After multivariate adjustment for characteristics known to be associated with voting rates, physicians were less likely to vote than the general population in 1998 (odds ratio 0.76; 95% confidence interval [CI] 0.59–0.99), 2000 (odds ratio 0.64; 95% CI 0.44–0.93), and 2002 (odds ratio 0.62; 95% CI 0.48–0.80) but not 1996 (odds ratio 0.83; 95% CI 0.59–1.17). Lawyers voted at higher rates than the general population and doctors in all four elections (P < .001). The pooled adjusted odds ratio for physician voting across the four elections was 0.70 (CI 0.61–0.81). No substantial changes in voting rates for health professionals were observed between 1976–1982 and 1996–2002. CONCLUSIONS: Physicians have lower adjusted voting rates than lawyers and the general population, suggesting reduced civic participation

Influence of soil and climate heterogeneity on the performance of economic instruments for reducing nitrate leaching from agriculture

Economic instruments can be used to control groundwater nitrate pollution due to the intensive use of fertilizers in agriculture. In order to test their efficiency on the reduction of nitrate leaching, we propose an approach based on the combined use of production and pollution functions to derive the impacts on the expected farmer response of these instruments. Some of the most important factors influencing nitrate leaching and crop yield are the type of soil and the climatic conditions. Crop yield and nitrate leaching responses to different soil and climaticconditions were classified by means of a cluster analysis, and crops located in different areas but with similar response were grouped for the analysis. We use a spatial economic optimization model to evaluate the potential of taxes on nitrogen fertilizers, water prices, and taxes on nitrate emissions to reduce nitrate pollution, as well as their economic impact in terms of social welfare and farmers' net benefits. Themethod was applied to theMancha Oriental System(MOS) in Spain, a large area with different soil types and climatic conditions.We divided the study area into zones of homogeneous crop production and nitrate leaching properties. Results how spatially different responses of crop growth and nitrate leaching, proving howthe cost-effectiveness of pollution control instruments is contingent upon the spatial heterogeneities of the problem.The study has been supported by the European Community 7th Framework Project GENESIS (226536) on groundwater.Peña Haro, S.; García Prats, A.; Pulido-Velazquez, M. (2014). Influence of soil and climate heterogeneity on the performance of economic instruments for reducing nitrate leaching from agriculture. Science of the Total Environment. 499:510-519. https://doi.org/10.1016/j.scitotenv.2014.07.029S51051949

Identifying patterns of alumni commitment in key strategic relationship programmes

Higher education institutions (HEIs) need to understand their alumni when drawing strategic relationship programmes. This paper aims to identify clusters of alumni based on their commitment relationship and to analyse factors influencing their intention to collaborate with the HEI. The study took place at a Portuguese university, considering a dataset of 1075 of alumni asserting intention to collaborate. First, a cluster analysis was conducted to identify patterns of commitment relationship. Secondly, a logistic regression was run to identify determinants of intention to collaborate. Both techniques revealed the decisive role of HEI commitment in the process. Relationship advantages and positive feelings towards the HEI were also pointed out as important. Alumni asserted recommendations, further training, sharing experiences and giving help as ways to collaborate with HEI. Regression results suggest that sociodemographic variables such as gender, marital status and volunteering are significantly associated with a probability to collaborate. Results also show that affiliation in sororities/fraternities and participation in extracurricular activities are significantly associated with that collaborative intention. The findings provide clues to support strategic relationship programmes based on consistent marketing campaigns, while bringing value to the literature in the European context, where alumni culture requires real insights to evolve.info:eu-repo/semantics/publishedVersio

Comparative mortality of hemodialysis patients at for-profit and not-for-profit dialysis facilities in the United States, 1998 to 2003: A retrospective analysis

<p>Abstract</p> <p>Background</p> <p>Concern lingers that dialysis therapy at for-profit (versus not-for-profit) hemodialysis facilities in the United States may be associated with higher mortality, even though 4 of every 5 contemporary dialysis patients receive therapy in such a setting.</p> <p>Methods</p> <p>Our primary objective was to compare the mortality hazards of patients initiating hemodialysis at for-profit and not-for-profit centers in the United States between 1998 and 2003. For-profit status of dialysis facilities was determined after subjects received 6 months of dialysis therapy, and mean follow-up was 1.7 years.</p> <p>Results</p> <p>Of the study population (<it>N </it>= 205,076), 79.9% were dialyzed in for-profit facilities after 6 months of dialysis therapy. Dialysis at for-profit facilities was associated with higher urea reduction ratios, hemoglobin levels (including levels above 12 and 13 g/dL [120 and 130 g/L]), epoetin doses, and use of intravenous iron, and less use of blood transfusions and lower proportions of patients on the transplant waiting-list (<it>P </it>< 0.05). Patients dialyzed at for-profit and at not-for-profit facilities had similar mortality risks (adjusted hazards ratio 1.02, 95% CI 0.99–1.06, <it>P </it>= 0.143).</p> <p>Conclusion</p> <p>While hemodialysis treatment at for-profit and not-for-profit dialysis facilities is associated with different patterns of clinical benchmark achievement, mortality rates are similar.</p

Alphavirus replicon particles containing the gene for HER2/neu inhibit breast cancer growth and tumorigenesis

INTRODUCTION: Overexpression of the HER2/neu gene in breast cancer is associated with an increased incidence of metastatic disease and with a poor prognosis. Although passive immunotherapy with the humanized monoclonal antibody trastuzumab (Herceptin) has shown some effect, a vaccine capable of inducing T-cell and humoral immunity could be more effective. METHODS: Virus-like replicon particles (VRP) of Venezuelan equine encephalitis virus containing the gene for HER2/neu (VRP-neu) were tested by an active immunotherapeutic approach in tumor prevention models and in a metastasis prevention model. RESULTS: VRP-neu prevented or significantly inhibited the growth of HER2/neu-expressing murine breast cancer cells injected either into mammary tissue or intravenously. Vaccination with VRP-neu completely prevented tumor formation in and death of MMTV-c-neu transgenic mice, and resulted in high levels of neu-specific CD8(+ )T lymphocytes and serum IgG. CONCLUSION: On the basis of these findings, clinical testing of this vaccine in patients with HER2/neu(+ )breast cancer is warranted

Derepression of CLDN3 and CLDN4 during ovarian tumorigenesis is associated with loss of repressive histone modifications

Unlike epigenetic silencing of tumor suppressor genes, the role of epigenetic derepression of cancer-promoting genes or oncogenes in carcinogenesis remains less well understood. The tight junction proteins claudin-3 and claudin-4 are frequently overexpressed in ovarian cancer and their overexpression was previously reported to promote the migration and invasion of ovarian epithelial cells. Here, we show that the expression of claudin-3 and claudin-4 is repressed in ovarian epithelial cells in association with promoter ‘bivalent’ histone modifications, containing both the activating trimethylated histone H3 lysine 4 (H3K4me3) mark and the repressive mark of trimethylated histone H3 lysine 27 (H3K27me3). During ovarian tumorigenesis, derepression of CLDN3 and CLDN4 expression correlates with loss of H3K27me3 in addition to trimethylated histone H4 lysine 20 (H4K20me3), another repressive histone modification. Although CLDN4 repression was accompanied by both DNA hypermethylation and repressive histone modifications, DNA methylation was not required for CLDN3 repression in immortalized ovarian epithelial cells. Moreover, activation of both CLDN3 and CLDN4 in ovarian cancer cells was associated with simultaneous changes in multiple histone modifications, whereas H3K27me3 loss alone was insufficient for their derepression. CLDN4 repression was robustly reversed by combined treatment targeting both DNA demethylation and histone acetylation. Our study strongly suggests that in addition to the well-known chromatin-associated silencing of tumor suppressor genes, epigenetic derepression by the conversely related loss of repressive chromatin modifications also contributes to ovarian tumorigenesis via activation of cancer-promoting genes or candidate oncogenes