Safety issues in PV systems: design choices for a secure fault detection and for preventing fire risk

Photovoltaic systems have played a key role over the last decade in the evolution of the electricity sector. In terms of safety design, it's important to consider that a PV plant constitutes a special system of generation, where the Direct Current (DC) presence results in changes to the technical rules. Moreover, if certain electrical faults occur, the plant is a possible source of fire. Choices regarding the grounding of the generator and its protection devices are fundamental for a design that evaluates fire risk. The subject of the article is the analysis of the relation between electrical phenomena in PV systems and the fire risk related to ensuring appropriate fault detection by the electrical protection system. A description of a grid-connected PV system is followed firstly by a comparison of the design solutions provided by international Standards, and secondly by an analysis of electrical phenomena which may trigger a fire. A study of two existing PV systems, where electrical faults have resulted in fires, is then presented. The study highlights the importance of checking all possible failure modes in a PV system design phase, to assess fire risk in advance. Some guidelines for the mitigation of electrical faults that may result in a fire are finally provided

Historical diversification of birds in Northwestern South America: A molecular perspective on the role of vicariant events

Studies of South American biodiversity have identified several areas of endemism that may have enhanced historical diversification of South American organisms. Hypotheses concerning the derivation of birds in the Choco area of endemism in northwestern South America were evaluated using protein electrophoretic data from 14 taxonomically diverse species groups of birds. Nine of these groups demonstrated that the Choco area of endemism has a closer historical relationship to Central America than to Amazonia, a result that is consistent with phytogeographic evidence. Within species groups, genetic distances between cis-Andean (east of the Andes) and trans-Andean (west of the Andes) taxa are, on average, roughly twice that between Choco and Central American taxa. The genetic data are consistent with the hypotheses that the divergence of most cis-Andean and trans-Andean taxa was the result of either the Andean uplift fragmenting a once continuous Amazonian-Pacific population (Andean Uplift Hypothesis), the isolation of the two faunas in forest refugia on opposite sides of the Andes during arid climates (Forest Refugia Hypothesis), or dispersal of Amazonian forms directly across the Andes into the trans-Andean region (Across-Andes Dispersal Hypothesis). Disentangling these hypotheses is difficult due to the complexity of the Andean uplift and to the scant geologic and paleoclimatic information that elucidates diversification events in northwestern South America. Regarding the divergence of cis- and trans-Andean taxa, the genetic, geologic, and paleoclimatic data allow weak rejection of the Andean Uplift Hypothesis and weak support for the Forest Refugia and Andean Dispersal Hypotheses. The subsequent diversification of Choco and Central American taxa was the result of Pleistocene forest refugia, marine transgressions, or parapatric speciation

Effects of Riverine Barriers on Genetic Differentiation of Amazonian Forest Undergrowth Birds (Peru).

The high frequency with which rivers delimit phenotypically differentiated bird taxa is unique to Amazonia, where major rivers often form the boundaries between allospecies and subspecies pairs of understory terra firme forest birds. In contrast, many such forest species with life history traits similar to these differentiated forms show no variation in plumage across even the largest rivers. To determine whether such species are nonetheless genetically differentiated, I obtained tissue samples from populations of forest understory birds from opposite banks of the Napo and Amazon rivers of northeastern Peru. These included three species that are not phenotypically differentiated across the Amazon and three species that are not phenotypically differentiated across the Napo, as well as two species that are phenotypically differentiated across the Amazon. Protein electrophoretic analysis of allozymes revealed substantial genetic differences among river-separated birds that do and do not show plumage differences. The prevailing historical hypothesis to explain the high number of species of Amazonian birds states that isolation in Pleistocene forest fragments was the important vicariant event that permitted speciation. An alternative is that isolation on opposite banks of rivers after the formation of the Amazonian river system was the important vicariant event. The pattern of genetic variation reported in this study supports the latter hypothesis. Wright\u27s coefficient {\rm F\sb{ST}} was used as an indirect index of the extent of gene flow among populations in contiguous forest. For some Amazonian species, {\rm F\sb{ST}} values are high compared to most temperate zone birds, especially considering the geographic proximity ($\u3c 90$ km) among the compared Amazonian populations. Increased population subdivision due to reduced effective population size or reduced effective dispersal distance, coupled with an aversion to crossing habitat discontinuities exposed to full sunlight, could explain the effect of riverine barriers on genetic differentiation within such species. The increased population subdivision and response to riverine barriers in understory terra firme forest birds suggests that the genetic continuity of these birds will be disrupted severely by the fragmentation of formerly contiguous forest through the building of roads and associated agricultural clearing currently underway in the Amazon basin

A case of nodular sclerosis Hodgkin’s lymphoma repeatedly relapsing in the context of composite plasma cell-hyaline vascular Castleman’s disease: successful response to rituximab and radiotherapy

We report the case of an Epstein-Barr virus (EBV)- and human immunodeficiency virus-serum negative patient suffering from repeatedly relapsing classical Hodgkin’s Lymphoma (cHL) associated with a histological picture of plasma cell-hyaline vascular (PC-HV) form of Castleman’s disease (CD). The CD30- and CD15- positive, Reed-Sternberg/Hodgkin cells, only occasionally expressed the CD20 molecule, but not leukocyte common antigen and latent membrane protein-1. Single-strand polymerase chain reaction failed to detect human herpesvirus 8 or EBV in the involved tissues. At the time of second relapse in July 2005, the clinical picture was characterized by a palpable right hypogastric mass, disclosed at physical exam, in the absence of other enlarged peripheral lymph nodes, subjective symptoms or laboratory profile alterations. Combined hybrid-(18)F-fluorodeoxyglucose positron emission-computerized tomography (18F-FDG PET/CT) showed increased radionuclide uptake in multiple external iliac lymph nodes [standardized uptake value (SUV) of 7.4] and non-palpable left supraclavicular lymph nodes (SUV of 5.8). Relapsing cHL in the context of mixed PC-HV CD was documented in two of three surgically excised abdominal lymph nodes never previously enlarged or involved by any lymphoproliferative disease. Because of the limited disease extension and failure to induce continuous remission with previous conventional chemoradiotherapy, the patient was treated with six rituximab injections. This immunotherapy induced significant reduction in size of supraclavicular lymph nodes as evident at ultrasound (US) scan (<1 vs. 2.5 cm, post- vs. pretherapy), which was confirmed by the 18F-FDG PET/CT in October 2005, despite no modification in SUV of 4.2. 18F-FDG PET/CT also disclosed no radionuclide uptake by abdominal lymph nodes. Thus, a second course of four additional rituximab injections was given and subsequent 18F-FDG PET/CT indicated persistent, but reduced incorporation of radionuclide compared to the pretherapy value (SUV of 2.7) in the supraclavicular area and confirmed a normal metabolic activity in the iliac external lymph nodes. Because of uncertain persistent disease in the supraclavicular nodal site, involved-field radiotherapy (RT) was delivered in that area as consolidation treatment. After completion of rituximab and RT for 16 and 14 months respectively, US and 18F-FDG PET/CT exams were indicative of complete remission. This case is in concordance with previously published data suggesting that rituximab immunotherapy might be a valid option in the treatment of CD and also have a role in the management of relapsing cHL

Isospora dendrocinclae n. sp. (Apicomplexa: Eimeriidae) from the Whitechinned Woodcreeper (Dendrocincla merula) from South America

A new species of Isospora is described from the fecal contents of the white-chinned woodcreeper, Dendrocincla merula merula from Guyana and Dendrocincla merula barletti from Peru. Sporulated oocysts are subspherical to ovoid, 19.2 × 16.5 (15–23 × 14.5–19) μm, with a smooth, colorless, bilayered wall. The average shape index is 1.2. No micropyle or oocyst residuum are present, but the oocysts contain one polar granule. Sporocysts are ovoid, 12.9 × 8.3 (12–14 × 7–10) μm, average shape index of 1.7 with a smooth, single layered wall and composed of a small, knoblike Stieda body and a slightly larger, bubble shaped substieda body. The two sporocysts each contain a compact residuum composed of coarse, non-uniform granules and four randomly arranged, vermiform sporozoites each with a terminal refractile body and a centrally located nucleus. DNA sequences representing ITS-1 and ITS-4 regions of the 5.8S rDNA gene from the two isolates were amplified and compared. In addition to the two isolates showing similar morphological characteristics, they also had identical nucleotide sequences for the ITS-1 and ITS-4 regions of the 5.8S ribosomal gene

Efficacy of anidulafungin in 539 patients with invasive candidiasis: a patient-level pooled analysis of six clinical trials

Item does not contain fulltextObjectives: To evaluate the efficacy of anidulafungin for the treatment of candidaemia and invasive candidiasis in a large dataset, including patients with deep-seated tissue candidiasis, neutropenia and infection due to non- albicans Candida species. Methods: Data were pooled from six prospective, multicentre, multinational studies: four open-label, non-comparative studies of anidulafungin and two double-blind, double-dummy, randomized studies of anidulafungin versus caspofungin (clinical trial registrations: NCT00496197, NCT00548262, NCT00537329, NCT00689338, NCT00806351 and NCT00805740; ClinicalTrials.gov). In all studies, patients with culture-confirmed invasive candidiasis received a single intravenous (iv) loading dose of anidulafungin 200 mg on day 1, followed by 100 mg once-daily. Switch to oral fluconazole or voriconazole was permitted after 5-10 days of iv treatment in all studies except one. Antifungal treatment (iv plus oral therapy if applicable) was maintained for >/=14 days after the last positive Candida culture. The primary endpoint was successful global response at end of iv therapy (EOivT) in the modified ITT (mITT) population. Results: In total, 539 patients were included (mITT population). The most common baseline Candida species were Candida albicans (47.9%), Candida glabrata (21.0%), Candida tropicalis (13.7%), Candida parapsilosis (13.2%) and Candida krusei (3.5%). Median duration of anidulafungin iv treatment was 10.0 days. The global response success rate at EOivT was 76.4% (95% CI 72.9%-80.0%). All-cause mortality was 13.0% on day 14 and 19.1% on day 28. Adverse events (AEs) were consistent with the known AE profile for anidulafungin. Conclusions: These data demonstrate that anidulafungin is effective for treatment of candidaemia and invasive candidiasis in a broad patient population

Efficacy of tigecycline for the treatment of complicated intraabdominal infections in real-life clinical practice from five european observational studies

Objectives: Tigecycline is a broad-spectrum antibiotic approved for the treatment of complicated intra-abdominal infections (cIAIs). The efficacy of tigecycline when administered as monotherapy or in combination with other antibacterials in the treatment of cIAIs in routine clinical practice is described. Patients and methods: Individual patient-level data were pooled from five European observational studies (July 2006 to October 2011). Results: A total of 785 cIAI patients who received tigecycline were included (mean age 63.1+14.0 years). Of these, 56.6% were in intensive care units, 65.6% acquired their infection in hospital, 88.1% had at least one comorbidity and 65.7% had secondary peritonitis. The mean Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores at the beginning of treatment were 16.9+7.6 (n=614) and 7.0+4.2 (n=108), respectively, indicating high disease severity. Escherichia coli (41.8%), Enterococcus faecium (40.1%) and Enterococcus faecalis (21.1%) were the most frequently isolated pathogens; 49.1% of infections were polymicrobial and 17.5% were due to resistant pathogens. Overall, 54.8% (n=430) received tigecycline as monotherapy and 45.2% (n=355) as combination therapy for a mean duration of 10.6 days. Clinical response rates at the end of treatment were 77.4% for all patients (567/733), 80.6% for patients who received tigecycline as monotherapy (329/408), 75.2% for patients with a nosocomial infection (354/471), 75.8% for patients with an APACHE II score .15 (250/330) and 54.2% (32/59) for patients with a SOFA score =7. Conclusions: In these real-life studies, tigecycline, alone and in combination, achieved favourable clinical response rates in patients with cIAI with a high severity of illness