5,819 research outputs found

    Dueling Loyalties: Honor, Citizenship, and Antisemitism in Nineteenth Century Germany

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    Joan and Henry Katz Lecture in Judaic Studies… David Meola, PhD. Author, Bert & Fanny Meisler Chair in History and Jewish Studies, University of South Alabama.https://digitalcommons.fairfield.edu/bennettcenter-posters/1361/thumbnail.jp

    Study of deposition of YBa2Cu3O7-x on cubic zirconia

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    Films of YBa2Cu3O7-x were grown on (100) cubic zirconia with 8 percent yttria by laser ablation from sintered targets of YBa2Cu3O7-x. The temperature of the zirconia substrate during growth was varied between 700 and 780 C. The atmosphere during growth was 170 mtorr of O2. The films were subsequently slowly cooled in-situ in 1 atm of O2. The best films were c-axis aligned and had a transition temperature of 87.7 K. The superconducting transition temperature and the X-ray diffraction analysis is reported as a function of the substrate temperature and of the angle between the laser beam and the target's normal

    Laser ablated high T(sub c) superconducting thin YBa2Cu3O(7-x) films on substrates suitable for microwave applications

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    The development of high temperature superconducting YBa2Cu3O(7-x) thin films on substrates suitable for microwave applications is of great interest for evaluating their applications for space radar, communication, and sensor systems. Thin films of YBa2Cu3O(7-x) were formed on SrTiO3, ZrO2, MgO, and LaAlO3 substrates by laser ablation. The wavelength used was 248 nm from a KrF excimer laser. During deposition the films were heated to 600 C in a flowing oxygen environment, and required no post annealing. The low substrate temperature during deposition with no post annealing gave films which were smooth, which had their c-axis aligned to the substrates, and which had grains ranging from 0.2 to 0.5 microns in size. The films being c-axis aligned gave excellent surface resistance at 35 GHz which was lower than that of copper at 77 K. At present, LaAlO3 substrates with a dielectric constant of 22, appears suitable as a substrate for microwave and electronic applications. The films were characterized by resistance-temperature measurements, scanning electron microscopy, and x ray diffraction. The highest critical transition temperatures (T sub c) are above 89 K for films on SrTiO3 and LaAlO3, above 88 K for ZrO2, and above 86 K for MgO. The critical current density (J sub c) of the films on SrTiO3 is above 2 x 10(exp 6) amperes/sq cm at 77 K. The T(sub c) and J(sub c) are reported as a function of laser power, composition of the substrate, and temperature of the substrate during deposition

    Decomposizione di lettiere singole e miste di Quercus ilex L., Pistacia lentiscus L., Phillyrea angustifolia L., e Cistus spp. in un area a macchia bassa della Riserva di Castel Volturno (Sud Italia)

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    La maggior parte dei lavori sulla decomposizione riguardano lettiera di foglie di singole specie; pochissimi sono gli studi su lettiere miste più adeguati a rappresentare gli effetti della diversità delle comunità vegetali su questo processo. In questa ricerca la decomposizione di Quercus ilex L., Pistacia lentiscus L., Phillyrea angustifolia e Cistus spp., è stata studiata utilizzando sacchetti di lettiera di una sola specie e sacchetti di lettiere miste per un totale di 10 tipologie di sacchetti. Le proporzioni delle singole specie nelle miscele erano 33:33:33 e 50:25:25. I sacchetti di lettiera sono stati incubati nella macchia bassa della Riserva Naturale di Castel Volturno, nella stessa area nella quale era stata effettuata la raccolta di lettiera. La decomposizione e la colonizzazione fungina sono state determinate dopo 96 giorni di incubazione. La lettiera pura di cisto in circa 3 mesi perde il 25 % del peso iniziale; in miscela con fillirea e con lentisco presenta valori significativamente più bassi di decomposizione e di colonizzazione fungina. Nello stesso periodo la fillirea perde il 23 % del suo peso iniziale. Le lettiere di leccio e di lentisco, caratterizzate da un più alto contenuto iniziale di lignina presentano una decomposizione più lenta e perdono rispettivamente il 18% ed il 14% del peso iniziale. Non sono state evidenziate per fillirea, leccio e lentisco effetti delle miscele sulla decomposizione

    Productivity and modifications of ecosystem processes in gaps of a low Macchia in southern Italy

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    Disturbance in Mediterranean shrub lands creates gaps that break up the shrub cover and potentially restrict productivity and other ecosystem processes. Gaps make up to about 20% of the low Macchia area at the Castel Volturno nature reserve (southern Italy). The plant community consists mainly of small annual species (legumes, grasses and forbs) that germinate in November and die out before the onset of summer drought. The inter-annual variability in productivity and the relative abundance of legumes, grasses and forbs were assessed over 4 yr (2004–2007) to evaluate main potential modifications of ecosystem processes determined by the occurrence of gaps in the shrub cover. <br><br> In the study years, at the peak production, plant mass varied from about 250 to 700 g m<sup>−2</sup>; biomass belowground allocation varied from 23% in the wettest to 44% in the driest year. Belowground/aboveground biomass ratios were negatively related to rainfall and positively related to the length of the dry period, showing that water availability controls biomass allocation patterns. Legumes were the most abundant fraction (about 60%) of the aboveground mass in the wettest year. In the drier years legumes exhibited a shorter life cycle and senesced by mid-spring. Among the three functional groups monitored, legumes were the most sensitive to water shortage and their biomass was positively related to the amount of rainfall and negatively related to the length of the dry period. The higher fraction of legume mass was associated with higher nitrogen content in plant tissues and in the soil. Senesced annual species decomposed more than senescent <i>Phillyrea</i> sp. leaves. The stability of organic carbon pool, evaluated through the endogenous mineralization coefficient (CEM), was lower in gaps than in understorey soils

    Ultrasound evaluation of access complications: Thrombosis, aneurysms, pseudoaneurysms and infections

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    : Arteriovenous fistula (AVF) complications are classified based on fistula outcomes. This review aims to update colour Doppler (CD) and pulse wave Doppler (PWD) roles in managing early and late complications of the native and prosthetic AVF. Vascular access (VA) failure occurs because inflow or outflow stenosis activates Wirchow's triad inducing thrombosis. Therefore, the diagnosis of the tributary artery and outgoing vein stenosis will be the first topic considered. Post-implantation complications occur from the inability to achieve AVF maturation and dialysis suitability due to inflow/outflow stenosis. Late stenosis is usually a sequence of early defects repaired to maintain patency. Less frequently, in the mature AVF or graft, complications are acquired 'de novo'. They derive either from incorrect management of vascular access (haematoma, pseudoaneurysm, prosthesis infection) or wall pathologies (aneurysm, myxoid valve degeneration, kinking, coiling, abnormal dilation from defects of elastic structures). High-resolution transducers (10-20 MHz) allow the characterization of the wall damage, haemodynamic dysfunctions, early and late complications even if phlebography remains the gold standard for the diagnosis for its sensitivity and specificity
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