Electrons on a sphere in disorder potential

We investigate, both analytically and numerically, the behavior of the electron gas on a sphere in the presence of point-like impurities. We find a criterion when the disorder can be regarded as small one and the main effect is the broadening of rotational multiplets. In the latter regime the statistics of one impurity-induced band is studied numerically. The energy level spacing distribution function follows the law P(s) ~ s exp(-a s^b) with 1<b<2. The number variance shows various possibilities, strongly dependent on the chosen model of disorder.Comment: 11 pages, REVTEX, 9 eps figures; references added to Sec.

Consistent Anisotropic Repulsions for Simple Molecules

We extract atom-atom potentials from the effective spherical potentials that suc cessfully model Hugoniot experiments on molecular fluids, e.g., $O_2$ and $N_2$. In the case of $O_2$ the resulting potentials compare very well with the atom-atom potentials used in studies of solid-state propertie s, while for $N_2$ they are considerably softer at short distances. Ground state (T=0K) and room temperatu re calculations performed with the new $N-N$ potential resolve the previous discrepancy between experimental and theoretical results.Comment: RevTeX, 5 figure

The Status of Coastal Benthic Ecosystems in the Mediterranean Sea: Evidence From Ecological Indicators

The Mediterranean Sea is subject to multiple human pressures increasingly threatening its unique biodiversity. Spatially explicit information on the ecological status of marine ecosystems is therefore key to an effective maritime spatial planning and management, and to help the achievement of environmental targets. Here, we summarized scientific data on the ecological status of a selection of marine ecosystems based on a set of ecological indicators in more than 700 sites of the Mediterranean Sea. For Posidonia oceanica seagrass beds, rocky intertidal fringe, and coastal soft bottoms, more than 70% of investigated sites exhibited good to high ecological conditions. In contrast, about two-thirds of sites for subtidal rocky reefs were classified to be in moderate to bad conditions, stressing the need for prioritizing conservation initiatives on these productive and diverse environments. Very little quantitative information was available for the southern Mediterranean Sea, thus monitoring programs and assessments in this area are essential for a representative assessment of the health of marine coastal ecosystems in the whole basin. This overview represents a first step to implement a baseline that, through georeferenced data on ecological status, could help identifying information gaps, directing future research priorities, and supporting improvements to spatial models of expected cumulative impacts on marine ecosystems

Occurrence of grapevine virus A (GVA) and other closteroviruses in Tunisian grapevines affected by leafroll disease

Vorkommen von Grapevine-Virus A (GVA) und anderen Closteroviren in blattrollkranken tunesischen RebenReben, die aus den Hauptweinbaugebieten Tunesiens stammten, wurden auf die Anwesenheit von Closteroviren hin überprüft. Während in keiner der symptomfreien Reben Viruspartikel entdeckt wurden, enthielten alle Reben mit Blattrollsymptomen - außer zweien - Closteroviruspartikel, die durch IEM (immune electron microscopy) in konzentrierten Blattextrakten oder unmittelbar in Rohsaft durch ISEM (immunosorbent electron microscopy) identifiziert wurden. Alle vier derzeit bekannten Closteroviren (GClV-1, GClV-2, GClV-3 und GVA) waren, meistens im Gemisch, in Reben mit Blattrollsymptomen vorhanden. GClV-3 und GVA wurden in 77 bzw. 50 % der geprüften Reben entdeckt. Ein tunesisches Isolat von GVA, das durch Planococcus citri auf krautige Testpflanzen übertragen wurde, unterschied sich in biologischer Hinsicht, aber nicht in den charakteristischen physikalisch-chemischen und serologischen Eigenschaften von zwei italienischen Isolaten desselben Virus

Pharmacological And Genetic Reversal Of Age-Dependent Cognitive Deficits Attributable To Decreased Presenilin Function

Alzheimer\u27s disease (AD) is the leading cause of cognitive loss and neurodegeneration in the developed world. Although its genetic and environmental causes are not generally known, familial forms of the disease (FAD) are attributable to mutations in a single copy of the Presenilin (PS) and amyloid precursor protein genes. The dominant inheritance pattern of FAD indicates that it may be attributable to gain or change of function mutations. Studies of FAD-linked forms of presenilin (psn) in model organisms, however, indicate that they are loss of function, leading to the possibility that a reduction in PS activity might contribute to FAD and that proper psn levels are important for maintaining normal cognition throughout life. To explore this issue further, we have tested the effect of reducing psn activity during aging in Drosophila melanogaster males. We have found that flies in which the dosage of psn function is reduced by 50% display age-onset impairments in learning and memory. Treatment with metabotropic glutamate receptor (mGluR) antagonists or lithium during the aging process prevented the onset of these deficits, and treatment of aged flies reversed the age-dependent deficits. Genetic reduction of Drosophila metabotropic glutamate receptor (DmGluRA), the inositol trisphosphate receptor (InsP(3)R), or inositol polyphosphate 1-phosphatase also prevented these age-onset cognitive deficits. These findings suggest that reduced psn activity may contribute to the age-onset cognitive loss observed with FAD. They also indicate that enhanced mGluR signaling and calcium release regulated by InsP(3)R as underlying causes of the age-dependent cognitive phenotypes observed when psn activity is reduced

Clinical and Genotypical Features of False-Negative Patients in 26 Years of Cystic Fibrosis Neonatal Screening in Tuscany, Italy.

Cystic fibrosis (CF) is a life-threatening and common genetic disorder. Cystic fibrosis newborn screening (CF NBS) has been implemented in many countries over the last 30 years, becoming a widely accepted public health strategy in economically developed countries. False-negative (FN) cases can occur after CF NBS, with the number depending on the method. We evaluated the delayed diagnosis of CF, identifying the patients who had false-negative CF NBS results over 26 years (1992-2018) in Tuscany, Italy. The introduction of DNA analysis to the newborn screening protocol improved the sensitivity of the test and reduced the FNs. Our experience showed that, overall, at least 8.7% of cases of CF received FNs (18 cases) and were diagnosed later, with an average age of 6.6 years (range: 4 months to 22 years). Respiratory symptoms and salt-loss syndrome (metabolic hypochloremic alkalosis) are suggestive symptoms of CF and were commons events in FN patients. In Tuscany, a region with a high CFTR allelic heterogeneity, the salt-loss syndrome was a common event in FNs. Therefore, we provided evidence to support the claim that the FN patients had CFTR mutations rarer compared with the true-positive cases. We underline the importance of vigilance toward clinical manifestations suggestive of CF on the part of the primary care providers and hospital physicians in a region with an efficient newborn screening program

Comparative characterization of fruit quality, phenols and antioxidant activity of de-pigmented “Ghiaccio” and white flesh peaches

Quality traits and nutraceutical potential of new de-pigmented peaches ("Ghiaccio") were investigated and compared with those of four white flesh peaches. Total soluble solids (TSS) were measured by digital refractometer, and titratable acidity (TA) by volumetric titration. Total phenolic (TPC) and anthocyanin content (TAC) were analysed spectrophotometrically and the antioxidant capacity (AC) evaluated by DPPH· assay. A strong influence of genotype on quality traits and phytochemical profile of "Ghiaccio" peaches was observed. "Ghiaccio" series showed, on average, a higher TPC content than that of white flesh peaches, both in flesh and peels (+129% and +14%, respectively). The peels of all peaches analysed were significantly richer in TPC than the flesh. TAC was not detectable in de-pigmented genotypes; on the contrary, in the white flesh peaches, it was higher in the peels than in the flesh. AC correlated well with TPC. Data confirm, for all peaches analysed, the influence of genotype and fruit tissue on the nutraceutical properties. Among genotypes, the best candidates for "Ghiaccio" peaches with enriched nutraceutical properties are the advanced selections GØ and GX. Observed differences in the nutraceutical potential among "Ghiaccio" series may open new opportunities for breeding de-pigmented peach varieties with a higher nutritional value