944 resultados para projectile fragmentation
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Several factors, such as hunting and the pet trade, are responsible for the worldwide decline of wildlife populations. In addition, fatal collisions with vehicles on highways have also taken one of the largest tolls. This study aimed to quantify the richness and abundance of vertebrate roadkill along highway MS-080 in Mato Grosso do Sul, Central-West Brazil. We compare the amount of roadkill to the distance between cities, moon phases and the flow of vehicles on the highway. Samples were collected weekly between March and September 2011, totaling 257 individuals, belonging to 32 families and 52 species, resulting in an index of 0.13 individuals hit/km. Birds were the most frequently hit taxa, followed by mammals. The most affected species was Cariama cristata (Cariamidae), followed by Cerdocyon thous (Canidae). The sections of highway closest to cities had the highest number of individual animals killed. Our observations indicate that the density of the vegetation next to the highway positively influences the amount of roadkill.
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The Araneidae is a speciose family including web-spinning spiders that are very abundant in various terrestrial ecosystems. Several studies demonstrate that changes in vegetation surrounding rivers, streams and brooks affect the associated araneofauna. The aim of this research was to compare differences found in diversity (abundance and richness), composition and phenology of Araneidae spiders sampled in different habitats in four riparian forest catchments in southern Brazil. Samples were taken from riparian forests in four rivers of Rio Grande do Sul State: Piratini, Camaquã, Sinos and Maquiné rivers, each in a different hydrographic basin. Samples were taken twice seasonally on each basin during two years, sampling the araneofauna of the tree-shrub strata with beating tray. Six transects were employed on each basin, two per habitat: edge with grassland, forest interior and river edge. Araneids totalled 20 genera and 65 species. Comparing riparian forests significant differences are found. Spider abundance differed among riparian forests as well as species richness. Overall, Piratini river riparian forest had the higher abundance and richness for Araneidae; the lower values were in Sinos river forest. The stronger degradation and fragmentation of the riparian forests of Sinos river probably influenced the results, with human disturbance gradients associated negatively to web building. We present data on the diversity of these spiders, which were very abundant in the riparian forest interior and very rich in species in the grassland/riparian forest edge. Species composition also differs among the studied habitats (the above plus river/riparian forest edge). For the most abundant species the phenological pattern across the seasons was also analysed.
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Since von Hibler gas grangrene has been considered a local infection with systemic symptoms. When we consider some of the symptoms of gas gangrene, those of the central nervous system are in evidence beeing similar to those observed in tetanus and botulism. It is likely therefore that gas gangrene intoxication and the disease caused by it are of neurotoxic nature. With Almeida Cardoso and Araujo Costa we were able to demonstrate lesions in the central nervous system of animals wich had been intoxicated during a short period of time as well in those with intoxication of longer duration. In acute intoxication, after intracreneal inoculation, severe alterations were seen within 20 to 30 minutes in the cells of the spinal cord, specially in motor cells and also in some cells of the posterior cord and spinal bulb. The changes consisted in chromatolysis and picnosis and were more marked in animals intoxicated with Clostridium histolyticum and Cl. perfringens toxines. Myelin sheet was unchanged. in delayed intoxication with greater and repeated dosis lesions of the central nervous system (brain, protuberance, medula ablongate and medula spinal) were observed. They consisted in hyperemia, perivascular hemorrages in white and grey substances, oedema, accumulation of glia cells with enlarged and hyperchromatic nuclei, fragmentation of the myelin sheet and balooning degeneration of the described by Spielmeyer. Such changes were found in the swollen and hemorragic zones and were generally similar to those found in the acute type of Spielmeyer 9acute swelling and liquefation). Other changes found sometimes were agglutination of Nissl's bodies, sinous appearence of the dendritic endings, shruncken cells of Spielmeyer and neuronophagy around "ghost" cells. In short the changes...
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An earlier study revealed the strong phylogeographical structure of the lesser white-toothed shrew (Crocidura suaveolens group) within the northern Palaearctic. Here, we aim to reconstruct the colonization history of Mediterranean islands and to clarify the biogeography and phylogeographical relationships of the poorly documented Middle East region with the northern Palaearctic. We performed analyses on 998-bp-long haplotypes of the mitochondrial cytochrome b gene of 143 samples collected around the Mediterranean basin, including islands and the Middle East. The analyses suggest that the Cypriot shrew belongs to the rare group of relict insular Pleistocene mammal taxa that have survived to the present day. In contrast, the Cretan, Corsican and Menorcan populations were independently introduced from the Middle East during the Holocene. The phylogeographical structure of this temperate Palaearctic species within the Middle East appears to be complex and rich in diversity, probably reflecting fragmentation of the area by numerous mountain chains. Four deeply divergent clades of the C. suaveolens group occur in the area, meaning that a hypothetical contact zone remains to be located in central western Iran.
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Introduced in 2008, the femtosecond laser is a promising new technological advance which plays an ever increasing role in cataract surgery where it automates the three main surgical steps: corneal incision, capsulotomy and lens fragmentation. The proven advantages over manual surgery are: a better quality of incision with reduced induced astigmatism; increased reliability and reproducibility of the capsulotomy with increased stability of the implanted lens; a reduction in the use of ultrasound. Regarding refractive results or safety, however, no prospective randomized study to date has shown significant superiority compared with standard manual technique. The significant extra cost generated by this laser, undertaken by the patient, is a limiting factor for both its use and study. This review outlines the potential benefits of femtosecond-laser-assisted cataract surgery due to the automation of key steps and the safety of this new technology.
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Although chronic hypoxia is a claimed myocardial risk factor reducing tolerance to ischemia/reperfusion (I/R), intermittent reoxygenation has beneficial effects and enhances heart tolerance to I/R. AIM OF THE STUDY: To test the hypothesis that, by mimicking intermittent reoxygenation, selective inhibition of phosphodiesterase-5 activity improves ischemia tolerance during hypoxia. Adult male Sprague-Dawley rats were exposed to hypoxia for 15 days (10% O₂) and treated with placebo, sildenafil (1.4 mg/kg/day, i. p.), intermittent reoxygenation (1 h/day exposure to room air) or both. Controls were normoxic hearts. To assess tolerance to I/R all hearts were subjected to 30-min regional ischemia by left anterior descending coronary artery ligation followed by 3 h-reperfusion. Whereas hypoxia depressed tolerance to I/R, both sildenafil and intermittent reoxygenation reduced the infarct size without exhibiting cumulative effects. The changes in myocardial cGMP, apoptosis (DNA fragmentation), caspase-3 activity (alternative marker for cardiomyocyte apoptosis), eNOS phosphorylation and Akt activity paralleled the changes in cardioprotection. However, the level of plasma nitrates and nitrites was higher in the sildenafil+intermittent reoxygenation than sildenafil and intermittent reoxygenation groups, whereas total eNOS and Akt proteins were unchanged throughout. CONCLUSIONS: Sildenafil administration has the potential to mimic the cardioprotective effects led by intermittent reoxygenation, thereby opening the possibility to treat patients unable to be reoxygenated through a pharmacological modulation of NO-dependent mechanisms.
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This paper offers an integrated analysis of the forces shaping the emergence of the African slave trade over the early modern period. We focus our attention on two questions. First, why most of the increase in the demand for slaves during this period came exclusively from western Europeans. Second, and of most relevance for present-day development outcomes, why was the overwhelming majority of slaves of African origin. Technological differences in manufacturing technology, the specificities of sugar (and other crops’) production, and the cultural fragmentation of the African continent all play a role in the analysis. Supporting evidence for each of our claims is provided from a broad corpus of relevant literature.
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OBJECTIVE To establish the role of the transcription factor Pax4 in pancreatic islet expansion and survival in response to physiological stress and its impact on glucose metabolism, we generated transgenic mice conditionally and selectively overexpressing Pax4 or a diabetes-linked mutant variant (Pax4R129 W) in β-cells. RESEARCH DESIGN AND METHODS Glucose homeostasis and β-cell death and proliferation were assessed in Pax4- or Pax4R129 W-overexpressing transgenic animals challenged with or without streptozotocin. Isolated transgenic islets were also exposed to cytokines, and apoptosis was evaluated by DNA fragmentation or cytochrome C release. The expression profiles of proliferation and apoptotic genes and β-cell markers were studied by immunohistochemistry and quantitative RT-PCR. RESULTS Pax4 but not Pax4R129 W protected animals against streptozotocin-induced hyperglycemia and isolated islets from cytokine-mediated β-cell apoptosis. Cytochrome C release was abrogated in Pax4 islets treated with cytokines. Interleukin-1β transcript levels were suppressed in Pax4 islets, whereas they were increased along with NOS2 in Pax4R129 W islets. Bcl-2, Cdk4, and c-myc expression levels were increased in Pax4 islets while MafA, insulin, and GLUT2 transcript levels were suppressed in both animal models. Long-term Pax4 expression promoted proliferation of a Pdx1-positive cell subpopulation while impeding insulin secretion. Suppression of Pax4 rescued this defect with a concomitant increase in pancreatic insulin content. CONCLUSIONS Pax4 protects adult islets from stress-induced apoptosis by suppressing selective nuclear factor-κB target genes while increasing Bcl-2 levels. Furthermore, it promotes dedifferentiation and proliferation of β-cells through MafA repression, with a concomitant increase in Cdk4 and c-myc expression.
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Optical and electron microscopical evidences of focal matrix degradation were frequently seen in liver sections taken from patients with periportal ("pipe-stem") fibrosis caused by schistosomiasis mansoni. Besides present of focal areas of rarefaction, fragmentation and dispersion of collagen fibers, the enlargend portal spaces also showed hyperplasia of elastic tisue and disarray of smooth muscle fibers following the destrution of portal vein branches. Ultrastructural cahnges represented by focal lytic and/or electron dense alterations of colagen fibrils were similar to those first seen in experimental material and designated as "chronic collagen degradation". Elastin and related microfibrils were also affected by focal condensation, fragmentation, distorsion and dissolution. Schistosome eggs were scanty in the tissue sections examined. Matrix degradation represented involuting changes related to the progressive diminution of parasite aggression, which occurs spontaneously with age or after cure by chemotherapy. Changes of focal matrix degradation now being described represent the basic morphological counterpart of periportal fibrosis involution documented clinically, especially by ultrasonography, in patients with hepatosplenic schistosomiasis submitted to curative chemotherapy.
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El litoral comprés entre els municipis de Torredembarra, Creixell i Roda de Berà és una platja sorrenca situada al nord de la comarca del Tarragonès. Aquest espai allotja la platja natural protegida més ben conservada entre el Delta del Llobregat i el Delta de l'Ebre, sent caracteritzada per les seves dunes de sorra i les llacunes salabroses. Al ser una zona costanera el principal problema són els impactes generats per la freqüentació turística que s'han avaluat en el present treball. La freqüentació ha generat nombrosos petits camins entre les dunes, afavorint la fragmentació, el sorgiment de la vegetació al·lòctona i la molèstia i canvi de comportament a espècies de fauna importants com el corriol camanegre (Charadrius alexandrinus).
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Metabolic labeling techniques have recently become popular tools for the quantitative profiling of proteomes. Classical stable isotope labeling with amino acids in cell cultures (SILAC) uses pairs of heavy/light isotopic forms of amino acids to introduce predictable mass differences in protein samples to be compared. After proteolysis, pairs of cognate precursor peptides can be correlated, and their intensities can be used for mass spectrometry-based relative protein quantification. We present an alternative SILAC approach by which two cell cultures are grown in media containing isobaric forms of amino acids, labeled either with 13C on the carbonyl (C-1) carbon or 15N on backbone nitrogen. Labeled peptides from both samples have the same nominal mass and nearly identical MS/MS spectra but generate upon fragmentation distinct immonium ions separated by 1 amu. When labeled protein samples are mixed, the intensities of these immonium ions can be used for the relative quantification of the parent proteins. We validated the labeling of cellular proteins with valine, isoleucine, and leucine with coverage of 97% of all tryptic peptides. We improved the sensitivity for the detection of the quantification ions on a pulsing instrument by using a specific fast scan event. The analysis of a protein mixture with a known heavy/light ratio showed reliable quantification. Finally the application of the technique to the analysis of two melanoma cell lines yielded quantitative data consistent with those obtained by a classical two-dimensional DIGE analysis of the same samples. Our method combines the features of the SILAC technique with the advantages of isobaric labeling schemes like iTRAQ. We discuss advantages and disadvantages of isobaric SILAC with immonium ion splitting as well as possible ways to improve it
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This research primarily analyses relevant climate bargaining dynamics that have been informed by a North-South impasse. This working paper argues that the first stage of negotiations for a climate convention indeed witnessed a North-South divide which became institutionalized in the Framework Convention on Climate Change. However, in subsequent negotiation rounds the key loci of bargaining struggles was centered between developed countries, in which relevant North-South cooperation dynamics were also present. Finally, this paper assesses the unfinished post-Kyoto bargaining process in which two trends are already being observed: both the emergence of a new geopolitics between the United States and major developing countries, and a fragmentation process within the South, in which the Copenhagen Accord itself has begun to institutionalize such fragmentation.
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The Cinque Torri group (Cortina d'Ampezzo, Italy) is an articulated system of unstable carbonatic rock monoliths located in a very important tourism area and therefore characterized by a significant risk. The instability phenomena involved represent an example of lateral spreading developed over a larger deep seated gravitational slope deformation (DSGSD) area. After the recent fall of a monolith of more than 10 000 m3, a scientific study was initiated to monitor the more unstable sectors and to characterize the past movements as a fundamental tool for predicting future movements and hazard assessment. To achieve greater insight on the ongoing lateral spreading process, a method for a quantitative analysis of rotational movements associated with the lateral spreading has been developed, applied and validated. The method is based on: i) detailed geometrical characterization of the area by means of laser scanner techniques; ii) recognition of the discontinuity sets and definition of a reference frame for each set, iii) correlation between the obtained reference frames related to a specific sector and a stable external reference frame, and iv) determination of the 3D rotations in terms of Euler angles to describe the present settlement of the Cinque Torri system with respect to the surrounding stable areas. In this way, significant information on the processes involved in the fragmentation and spreading of a former dolomitic plateau into different rock cliffs has been gained. The method is suitable to be applied to similar case studies.
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Cervical lymph nodes biopsies from 31 HIV positive patients (with or without AIDS) were studied by histologic methods and immunohistochemistry (StreptABC staining of paraffin sections) to identify cellular and extracellular matrix components. The results were the following: (1) the biopsies were included in the stages of follicular hyperplasia without fragmentation FH-FF (4 cases); follicular hyperplasia with follicular fragmentation FH+FF (16 cases); follicular involution FI (6 cases) and diffuse pattern DP (5 cases); (2) the most important alteration was the germinal centers disruption due to follicle lysis, which began in the light zone; (3) there was coincidence between intrafollicular hemorrhages and segmental hyaline mycroangiopathy; (4) during the progression of the disease occurred: (a) an increase in the number of mast cells, CD68+ and Mac387+ macrophages; (b) a diffuse augment of collagen III, elastic fibers, laminin, fibronectin and proteoglycans; (c) maintenance of Factor VIII - related antigens in the vascular endothelial cells, with decrease in the expression of Ulex-Europeus I lectin. Follicular hyperplasia (FH-FF or FH+FF) was the most common histologic pattern recognized in the lymph nodes of patients without AIDS and follicular involution and difuse pattern were seen in those who had AIDS. The results indicate that the lymph node biopsies may provide important information about the evolutive stage of the disease and its prognosis.
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Treatment of retinal detachment frequently uses biocompatible materials to obtain scleral buckling. These materials are not devoid of consequences on surrounding tissues. In 3 eyes enucleated for failure of surgical treatment using scleral buckling materials, the changes prompted by episcleral implants could be observed. The sclera underwent both an inversion of its curvature and a reduction of its thickness under the material, as well as an encapsulation of the material was observed. While a silicone sponge was used in part to encircle one of these eyes, its capsular inner surface was regular and smooth. In contrast, hydrogel implants used in the three eyes showed a peripheral fragmentation prompting in two of them a typical foreign body giant cell granulomatous reaction. Changes in scleral curvature and scleral thinning were observed reflecting the consequences of the buckling procedure. The capsule formation occurred as it does for any nonabsorbable matérial implanted in tissues. Degradation and fragmentation of the hydrogel material suscitated a granuloma in response to fragments. These hydrogel specific changes should be recognized on microscopic examination of slides of either capsule or eyes previously in contact with this implanted material. They attested of the instability of hydrogel after implantation.