170 research outputs found
Long-term changes and recurrent patterns in fisheries landings from Large Marine Ecosystems (1950–2004)
The regional dynamics of industrial fisheries within Large Marine Ecosystems (LMEs) boundaries were investigated by means of a historical-descriptive approach. Landings data from the Sea Around Us Project database were used to detect trends in total yields and variations in landings composition by functional groups over time. The temporal and spatial scales covered by this study allowed general issues to be addressed such as the detection of recurrent patterns and synchronies in fisheries landings. An unsuper-vised artificial neural network, Self Organizing Map (SOM), is used as a tool to analyze fisheries landings composition variation over five decades in 51 LMEs all over the world. From the historical analysis of “fishing behaviors” within LMEs a broad distinction between two main types of fisheries emerged: (1) small and medium pelagics fisheries, with stable compositions or cyclic behaviors, occurred in LMEs which share common productive features, despite different geographical locations and (2) demersal fisheries, which are more affected by economic drivers and tend to concentrate in LMEs in the Northern Hemisphere. Our analysis can be regarded as a first step towards the challenging scope of describing the relative influence of environmental and economic drivers on exploited ecosystems
Investigation of phase-separated electronic states in 1.5µm GaInNAs/GaAs heterostructures by optical spectroscopy
We report on the comparative electronic state characteristics of particular GaInNAs/GaAs quantum well structures that emit near 1.3 and 1.5 µm wavelength at room temperature. While the electronic structure of the 1.3 µm sample is consistent with a standard quantum well, the 1.5 µm sample demonstrate quite different characteristics. By using photoluminescence sPLd excitation spectroscopy at various detection wavelengths, we demonstrate that the macroscopic electronic states in the 1.5 µm structures originate from phase-separated quantum dots instead of quantum wells. PL measurements with spectrally selective excitation provide further evidence for the existence of composition-separated phases. The evidence is consistent with phase segregation during the growth leading to two phases, one with high In and N content which accounts for the efficient low energy 1.5 µm emission, and the other one having lower In and N content which contributes metastable states and only emits under excitation in a particular wavelength range
Interplay between charge trapping and polarization switching in BEOL-compatible bilayer Ferroelectric Tunnel Junctions
We here report a joint experimental and theoretical analysis of polarization switching in
ferroelectric tunnel junctions. Our results show that the injection and trapping of charge into the
ferroelectric-dielectric stack has a large influence on the polarization switching. Our results are relevant to the physical understanding and to the design of the devices, and for both memory and memristor
applications
200 mm wafer scale III-V/SOI technology for all-optical network-on-chip and signal processing
Integrated components, including microdisk lasers, photodetectors, and wavelength selective circuits, for optical network-on-chip and all-optical signal processing are presented using a complementary metal-oxide-semiconductor compatible III-V/silicon-on-insulator integration technology at 200mm wafer scale
What can be learned from phenotyping and genotyping analyses of Scedosporium prolificans isolates from diverse origins?
Introduction:
Scedosporium prolificans is a filamentous fungus considered as an emerging opportunistic member of the order Microascaceae. This fungus has a broad clinical spectrum and can cause different types of infections: localized colonization in immunocompetent hosts or disseminated mycosis in immunocompromised patients. Moreover, S. prolificans resistance to most antifungal agents has been reported. Compared to the well characterized Scedosporium / Pseudallescheria complex, little is known about the fundamental aspects of S. prolificans biology, pathogenicity and epidemiology.
Aim of the study:
Our goal was to characterize a large population of S. prolificans strains, isolated from animals, human, or environment samples in different countries (European, USA and Australia).
Results & methods:
All strains were prospectively collected, and grown at 30# C on Sabouraud’s agar medium with kanamycin for 1 week. DNA was extracted from subcultures using UltraClean Fecal# DNA kit (MoBio, France). To improve the knowledge of this species at the phylogenetic level, we combined phenotypic criteria such as macroscopic and microscopic morphology features, antifungal susceptibilities based on E-test# method, and genotypic characterization using multi-loci approaches (superoxide dismutase, beta-tubulin and internal transcript spacer genes). Phylogenetic trees were constructed with unambiguously CLUSTALW aligned sequences using the neighbour-joining method with Kimura-2 parameter as substitution model and maximum parsimony analysis, using the BioEdit version 7.0.0 and Phylip version 2.0 softwares.
Discussion:
Among our collection composed of 59 isolates, we identified three macroscopically different morphotypes of S. prolificans and some genetic polymorphisms (1.8–2.2% difference between the analyzed sequences). These low sequence polymorphisms reflected intra-specific genetic variations. Therefore, we hypothesized that S. prolificans might be stable in space, and apparently insensitive to xenical or environmental factors. No correlation between clinical-biological characteristics and genotypic or phenotypic criteria of S. prolificans strains was found. In conclusion, our results supported the current perception of S. prolificans as a unique species and an emerging opportunistic pathogen
Analysis of clinical and environmental Candida parapsilosis isolates by microsatellite genotyping – a tool for hospital infections surveillance
Candida parapsilosis emerged as an important opportunistic pathogen, causing candidaemia worldwide. Nosocomial outbreaks triggered by this species have been frequently described, particularly in cancer patients. For a better understanding of its epidemiology, several typing methods are used and microsatellite analysis has been reported as highly discriminant. The main objective of this work was to study C. parapsilosis isolates by application of microsatellite genotyping to distinguish epidemiologically related strains, compare clinical and environmental isolates and determine possible routes of dispersion of the isolates in the hospital setting. A total of 129 C. parapsilosis isolates from different origins, including hospital environment and hands of healthcare workers, were genotyped using four microsatellite markers. The isolates were recovered from different health institutions. Analysis of C. parapsilosis isolates from hospital environment showed great genotypic diversity; however, the same or very similar genotypes were also found. The same multilocus genotype was shared by isolates recovered from the hand of a healthcare worker, from the hospital environment and from patients of the same healthcare institution, suggesting that these could be possible routes of transmission and that infections due to C. parapsilosis may be mainly related with exogenous transmission to the patient. Examination of sequential isolates from the same patients showed that colonizing and bloodstream isolates had the same multilocus genotype in the majority of cases. We demonstrate that this typing method is able to distinguish clonal clusters from genetically unrelated genotypes and can be a valuable tool to support epidemiologic investigations in the hospital setting.This research was supported by FCT/MEC, Portugal through Portuguese funds (PIDDAC) - Pest-OE/BIA/UI4050/2014 (CBMA), University of Minho. Raquel Sabino was financially supported by a fellowship from FCT, Portugal (contract BD/22100/2005).info:eu-repo/semantics/publishedVersio
The frequency of adverse drug reaction related admissions according to method of detection, admission urgency and medical department specialty
The influence of environmental variables on the functional structure of headwater stream fish assemblages: a study of two tropical basins in Central Brazil
Divergent reaction of fish metrics to human pressures in fish assemblage types in Europe
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