109 research outputs found

    Law School Libraries 2007

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    The primary mission of the law school library is to meet the information needs of the faculty and students of the institution it supports. In addition to their role in educating future lawyers, law schools are the major producers of scholarly literature in law and rely on academic law libraries to provide the resources and support needed for research and publication. Beyond support for the core functions of legal education and research, the specific missions of law school libraries vary depending on the size and missions of law schools of different types. Differences among law schools result in differences among their libraries in collection size and composition, staffing and services offered, and additional clienteles served

    Arabidopsis thaliana leaves with altered chloroplast numbers and chloroplast movement exhibit impaired adjustments to both low and high light

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    The effects of chloroplast number and size on the capacity for blue light-dependent chloroplast movement, the ability to increase light absorption under low light, and the susceptibility to photoinhibition were investigated in Arabidopsis thaliana. Leaves of wild-type and chloroplast number mutants with mean chloroplast numbers ranging from 120 to two per mesophyll cell were analysed. Chloroplast movement was monitored as changes in light transmission through the leaves. Light transmission was used as an indicator of the ability of leaves to optimize light absorption. The ability of leaves to deal with 3 h of high light stress at 10 °C and their capacity to recover in low light was determined by measuring photochemical efficiencies of PSII using chlorophyll a fluorescence. Chloroplast movement was comparable in leaves ranging in chloroplast numbers from 120 to 30 per mesophyll cell: the final light transmission levels after exposure to 0.1 (accumulation response) and 100 μmol photons m−2 s−1 (avoidance response) were indistinguishable, the chloroplasts responded quickly to small increases in light intensity and the kinetics of movement were similar. However, when chloroplast numbers per mesophyll cell decreased to 18 or below, the accumulation response was significantly reduced. The avoidance response was only impaired in mutants with nine or fewer chloroplasts, both in terms of final transmission levels and the speed of movement. Only mutants lacking both blue light receptors (phot1/phot2) or those with drastically reduced chloroplast numbers and severely impacted avoidance responses showed a reduced ability to recover from high light stress

    Transport von Silbernanopartikeln in natürlich gelagerten Bodensäulen

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    Die Anzahl der wissenschaftlichen Untersuchungen zum Verbleib von Silbernanopartikeln (Ag-NP) in Böden hat in den letzten Jahren zugenommen. Da die publizierten Ergebnisse darauf hinweisen, dass sie stark durch die gewählten Versuchs- und Randbedingungen beeinflusst werden, bleibt die Bewertung der Mobilität von Silbernanopartikeln in Böden schwierig. Daher sollte der Transport und Verbleib der Ag-NP in dieser Untersuchung unter naturnahe Bedingung, aber mit kontrollierten Rand- und Anfangsbedingungen bestimmt werden. Dazu wurden an zwei Standorten (Sand, Schluff) jeweils acht ungestörte Bodensäulen (Ø 10,2 cm Höhe 16 cm) genommen und in einer Säulenversuchsanlage (SCS, Fa. emc GmbH) untersucht. Drei Säulen dienten jeweils als Parallelen während eine Säule als Kontrolle ohne Zugabe von NP untersucht wurde. Für beide Bodenarten erfolgten Versuche mit gesättigtem und ungesättigtem Fluss. Zur Nachverfolgung des Wasserflusses durch die Säulen wurde dem Beregnungswasser D2O als Tracer zugesetzt. Die Silbergesamtgehalte im Perkolat wurde nach HNO3-Aufschluss und mit ICP-OES/MS analysiert. Die Messung der gelösten Silberfraktion erfolgte nach Ultrazentrifugation mit ICP-MS. Die Größenverteilung von natürlichen Bodenkolloiden und Ag-NP wurde mit Dynamic Light Scattering (Malvern NanoZS) gemessen. Die Ergebnisse bestätigen den Einfluss der Versuchsbedingungen, zeigen aber auch die Bedeutung der Bodenstruktur auf die Mobilität der Ag-NP. Die Variabilität zwischen den Parallelproben ist sehr groß und überschattet mögliche Unterschiede zwischen den Bodenarten. Bevorzugte Fließwege sind wohl die Regel, die frühen Durchbrüche von D2O und Ag-NP bestätigt den präferentiellen Transport von Wasser und Partikeln. Mit Hilfe eines nachträglich durch die Säule perkolierten Farbstoffes (Brillant Blue) wurde Randfluss ausgeschlossen. Unter ungesättigten Bedingungen wird ein deutlich größerer Teil der Ag-NP im Boden zurückgehalten als unter gesättigten Fließbedingungen. Daher wird angenommen, dass die Bodenluft für die Retention der Partikel im Boden wichtig ist

    Helicobacter pylori Adapts to Chronic Infection and Gastric Disease via pH-Responsive BabA-Mediated Adherence

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    International audienceThe BabA adhesin mediates high-affinity binding of Helicobacter pylori to the ABO blood group antigen-glycosylated gastric mucosa. Here we show that BabA is acid responsive-binding is reduced at low pH and restored by acid neutralization. Acid responsiveness differs among strains; often correlates with different intragastric regions and evolves during chronic infection and disease progression; and depends on pH sensor sequences in BabA and on pH reversible formation of high-affinity binding BabA multimers. We propose that BabA's extraordinary reversible acid responsiveness enables tight mucosal bacterial adherence while also allowing an effective escape from epithelial cells and mucus that are shed into the acidic bactericidal lumen and that bio-selection and changes in BabA binding properties through mutation and recombination with babA-related genes are selected by differences among individuals and by changes in gastric acidity over time. These processes generate diverse H. pylori subpopulations, in which BabA's adaptive evolution contributes to H. pylori persistence and overt gastric disease

    Temporal migration rates affect the genetic structure of populations in the biennial Erysimum mediohispanicum with reproductive asynchrony

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    Funding was provided by projects CGL2009-07487/BOS and CGL2016-77720-P (AEI/FEDER, UE) to F.X.P., by the Impact Fellow programme from the University of Stirling to M.A. and by the Portuguese Foundation for Science and Technology (SFRH/BPD/111015/2015) to A.J.M.-P.We are grateful to Armando Caballero, Juan Pedro Martínez Camacho, Mario Vallejo-Marin, Mohammed Bakkali, Robin S. Waples, Xavier Thibert-Plante and Antonio Castilla for their comments and discussions on a previous draft of the manuscript. Esperanza Manzano, Leticia Ayllón and Rocío Gómez assisted in the laboratory. The EVOFLOR discussion group stimulated the development of this study. We thank the Sierra Nevada National Park headquarters for the permits and the support during our samplings in the field. We thank Bioportal at the University of Oslo and Residencia de Estudiantes de la Universidad de Zaragoza in Jaca for logistic support. We also thank the staff of the laboratory of molecular ecology (LEM) of the EBD-CSIC for assistance.Migration is a process with important implications for the genetic structure of populations. However, there is an aspect of migration seldom investigated in plants: migration between temporally isolated groups of individuals within the same geographic population. The genetic implications of temporal migration can be particularly relevant for semelparous organisms, which are those that reproduce only once in a lifetime after a certain period of growth. In this case, reproductive asynchrony in individuals of the same population generates demes of individuals differing in their developmental stage (non-reproductive and reproductive). These demes are connected by temporal migrants, that is, individuals that become annually asynchronous with respect to the rest of individuals of their same deme. Here, we investigated the extent of temporal migration and its effects on temporal genetic structure in the biennial plant Erysimum mediohispanicum. To this end, we conducted two independent complementary approaches. First, we empirically estimated temporal migration rates and temporal genetic structure in four populations of E. mediohispanicum during three consecutive years using nuclear microsatellites markers. Second, we developed a demographic genetic simulation model to assess genetic structure for different migration scenarios differing in temporal migration rates and their occurrence probabilities. We hypothesized that genetic structure decreased with increasing temporal migration rates due to the homogenizing effect of migration. Empirical and modelling results were consistent and indicated a U-shape relationship between genetic structure and temporal migration rates. Overall, they indicated the existence of temporal genetic structure and that such genetic structure indeed decreased with increasing temporal migration rates. However, genetic structure increased again at high temporal migration rates. The results shed light into the effects of reproductive asynchrony on important population genetic parameters. Our study contributes to unravel the complexity of some processes that may account for genetic diversity and genetic structure of natural populations.AEI/FEDER, UE CGL2009-07487/BOS CGL2016-77720-PImpact Fellow programme from the University of StirlingPortuguese Foundation for Science and Technology SFRH/BPD/111015/201

    Effect of rosuvastatin on outcomes in chronic haemodialysis patients – design and rationale of the AURORA study

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    BACKGROUND: Patients with end-stage renal disease (ESRD) are at high risk of cardiovascular events. Multiple risk factors for atherosclerosis are present in ESRD and may contribute to the increased risk of cardiovascular mortality in this population. In contrast to patients with normal renal function, the benefits of modifying lipid levels on cardiovascular outcomes in patients with ESRD on haemodialysis have yet to be confirmed in large prospective randomised trials. A study to evaluate the Use of Rosuvastatin in subjects On Regular haemodialysis: an Assessment of survival and cardiovascular events (AURORA) will be the first large-scale international trial to assess the effects of statin therapy on cardiovascular morbidity and mortality in ESRD patients on chronic haemodialysis. METHODS: More than 2,750 ESRD patients who have been receiving chronic haemodialysis treatment for at least 3 months have been randomised (1:1), irrespective of baseline lipid levels, to treatment with rosuvastatin 10 mg or placebo. The primary study endpoint is the time to a major cardiovascular event (first occurrence of cardiovascular death, non-fatal myocardial infarction or non-fatal stroke). Secondary endpoints include all-cause mortality, major cardiovascular event-free survival time, time to cardiovascular death, time to non-cardiovascular death, cardiovascular interventions, tolerability of treatment and health economic costs per life-year saved. Study medication will be given until 620 subjects have experienced a major cardiovascular event. CONCLUSION: Our hypothesis is that results from AURORA will establish the clinical efficacy and tolerability of rosuvastatin in patients with ESRD receiving chronic haemodialysis and guide the optimal management of this expanding population
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