9,053 research outputs found
Climate modification and climate change debates amongst Soviet physical geographers, 1940s-1960s
This review provides an insight into some of the main themes characterizing the work of Soviet physical geographers concerning climate during the decade following the Second World War. Post-1945, pressure was placed upon geography via the state and the Academy of Sciences to ensure that its activities were of practical use to the development of the socialist economy and this was particularly evident in the case of work related to climate and climate modification. The review is divided into four main sections. First, it provides an understanding of the range of work carried out by physical geographers with respect to climate and related phenomena in the late 1940s and 1950s. Second, it focuses on the work of geographers and climatologists in relation to the heat and water balance at the earth's surface, which attracted considerable attention within geographical circles as well as more broadly within Soviet science during the 1950s. Third, it reflects upon the way in which Soviet geography utilized its understanding of climate systems in order to participate in national schemes concerned with the modification of the climate and the transformation of nature. Finally, the review highlights the maturing of climate modification debates among geographers and cognate scientists during the late 1950s and early 1960s with the emergence of competing discussions over the potential for human activity to result in both positive and negative consequences for the global climate system
Optic neuritis
Acute optic neuritis is the most common optic neuropathy affecting young adults. Exciting developments have occurred over the past decade in understanding of optic neuritis pathophysiology, and these developments have been translated into treatment trials. In its typical form, optic neuritis presents as an inflammatory demyelinating disorder of the optic nerve, which can be associated with multiple sclerosis. Atypical forms of optic neuritis can occur, either in association with other inflammatory disorders or in isolation. Differential diagnosis includes various optic nerve and retinal disorders. Diagnostic investigations include MRI, visual evoked potentials, and CSF examination. Optical coherence tomography can show retinal axonal loss, which correlates with measures of persistent visual dysfunction. Treatment of typical forms with high-dose corticosteroids shortens the period of acute visual dysfunction but does not affect the final visual outcome. Atypical forms can necessitate prolonged immunosuppressive regimens. Optical coherence tomography and visual evoked potential measures are suitable for detection of neuroaxonal loss and myelin repair after optic neuritis. Clinical trials are underway to identify potential neuroprotective or remyelinating treatments for acutely symptomatic inflammatory demyelinating CNS lesions
Joining Inventory by Parataxonomists with DNA Barcoding of a Large Complex Tropical Conserved Wildland in Northwestern Costa Rica
BACKGROUND: The many components of conservation through biodiversity development of a large complex tropical wildland, Area de Conservacion Guanacaste (ACG), thrive on knowing what is its biodiversity and natural history. For 32 years a growing team of Costa Rican parataxonomists has conducted biodiversity inventory of ACG caterpillars, their food plants, and their parasitoids. In 2003, DNA barcoding was added to the inventory process. METHODOLOGY/PRINCIPAL FINDINGS: We describe some of the salient consequences for the parataxonomists of barcoding becoming part of a field biodiversity inventory process that has centuries of tradition. From the barcoding results, the parataxonomists, as well as other downstream users, gain a more fine-scale and greater understanding of the specimens they find, rear, photograph, database and deliver. The parataxonomists also need to adjust to collecting more specimens of what appear to be the "same species"--cryptic species that cannot be distinguished by eye or even food plant alone--while having to work with the name changes and taxonomic uncertainty that comes with discovering that what looked like one species may be many. CONCLUSIONS/SIGNIFICANCE: These career parataxonomists, despite their lack of formal higher education, have proven very capable of absorbing and working around the additional complexity and requirements for accuracy and detail that are generated by adding barcoding to the field base of the ACG inventory. In the process, they have also gained a greater understanding of the fine details of phylogeny, relatedness, evolution, and species-packing in their own tropical complex ecosytems. There is no reason to view DNA barcoding as incompatible in any way with tropical biodiversity inventory as conducted by parataxonomists. Their year-round on-site inventory effort lends itself well to the sampling patterns and sample sizes needed to build a thorough barcode library. Furthermore, the biological understanding that comes with barcoding increases the scientific penetrance of biodiversity information, DNA understanding, evolution, and ecology into the communities in which the parataxonomists and their families are resident
Diagnosis of multiple sclerosis: progress and challenges
The diagnosis of multiple sclerosis (MS) is based on typical neurological symptoms and signs along with evidence of dissemination of central nervous system (CNS) lesions in space and time. Magnetic resonance imaging (MRI) is often sufficient to confirm the diagnosis when characteristic lesions of MS accompany a typical clinical syndrome, but in some patients, further supportive information can be obtained from cerebrospinal fluid examination and neurophysiological testing. It is important to differentiate MS not only from other diseases in which demyelination is a feature e.g. neuromyelitis spectrum disorder (NMOSD) and acute disseminated encephalomyelitis (ADEM), but also non-demyelinating conditions such as chronic small vessel disease and other inflammatory, granulomatous, infective, metabolic and genetic causes that can mimic MS. Advances in MRI, serological and genetic tests have greatly helped in distinguishing MS from these conditions, but misdiagnosis can occur. In this review, we explore the progress and challenges in the diagnosis of MS with reference to diagnostic criteria, important differential diagnoses, current controversies and uncertainties, and future prospects
Reading the Complex Skipper Butterfly Fauna of One Tropical Place
BACKGROUND: An intense, 30-year, ongoing biodiversity inventory of Lepidoptera, together with their food plants and parasitoids, is centered on the rearing of wild-caught caterpillars in the 120,000 terrestrial hectares of dry, rain, and cloud forest of Area de Conservacion Guanacaste (ACG) in northwestern Costa Rica. Since 2003, DNA barcoding of all species has aided their identification and discovery. We summarize the process and results for a large set of the species of two speciose subfamilies of ACG skipper butterflies (Hesperiidae) and emphasize the effectiveness of barcoding these species (which are often difficult and time-consuming to identify). METHODOLOGY/PRINCIPAL FINDINGS: Adults are DNA barcoded by the Biodiversity Institute of Ontario, Guelph, Canada; and they are identified by correlating the resulting COI barcode information with more traditional information such as food plant, facies, genitalia, microlocation within ACG, caterpillar traits, etc. This process has found about 303 morphologically defined species of eudamine and pyrgine Hesperiidae breeding in ACG (about 25% of the ACG butterfly fauna) and another 44 units indicated by distinct barcodes (n = 9,094), which may be additional species and therefore may represent as much as a 13% increase. All but the members of one complex can be identified by their DNA barcodes. CONCLUSIONS/SIGNIFICANCE: Addition of DNA barcoding to the methodology greatly improved the inventory, both through faster (hence cheaper) accurate identification of the species that are distinguishable without barcoding, as well as those that require it, and through the revelation of species "hidden" within what have long been viewed as single species. Barcoding increased the recognition of species-level specialization. It would be no more appropriate to ignore barcode data in a species inventory than it would be to ignore adult genitalia variation or caterpillar ecology
Prediction of time between CIS onset and clinical conversion to MS using Random Forests
CIS is diagnosed after a first neurological attack and can be considered an early stage of MS as ~80% of all CIS patients will have a second relapse
within 20 years. The prediction of this second clinical relapse which marks the clinical conversion to MS (i.e., clinically-definite MS, CDMS) is very
challenging, and many clinical and radiological predictors of CDMS have been identified. Machine learning techniques such as support vector machines
(SVMs) have been widely applied to neuroimaging data in order to associate MRI features with binary clinical outcomes. A single-centre study has
shown that it is possible to predict short-time conversion after 1 and 3 years with an accuracy of ~75 % using a priori defined features from baseline MRI
measures and clinical characteristics, which were applied to support vector machines (SVMs).
Random forests are another type of machine learning techniques that can easily be applied to regression problems, and consist of an ensemble of
decision trees for regression where each tree is created from independent bootstraps from the input data.
The present study shows the feasibility of using random forests with European multi-centre MRI data (obtained at CIS onset) to predict the actual date of
conversion to CDMS rather than just a binary outcome at a fixed time point
Spatial and temporal dynamics of Atlantic menhaden (Brevoortia tyrannus) recruitment in the Northwest Atlantic Ocean
Atlantic menhaden, Brevoortia tyrannus, is an abundant, schooling pelagic fish that is widely distributed in the coastal Northwest Atlantic. It supports the largest single-species fishery by volume on the east coast of the United States. However, relatively little is known about factors that control recruitment, and its stock- recruitment relationship is poorly defined. Atlantic menhaden is managed as a single unit stock, but fisheries and environmental variables likely act regionally on recruitments. To better understand spatial and temporal variability in recruitment, fishery-independent time-series (1959-2013) of young-of-year (YOY) abundance indices from the Mid-Atlantic to Southern New England (SNE) were analysed using dynamic factor analysis and generalized additive models. Recruitment time-series demonstrated low-frequency variability and the analyses identified two broad geographical groupings, the Chesapeake Bay (CB) and SNE. Each of these two regions exhibited changes in YOY abundance and different periods of relatively high YOY abundance that were inversely related to each other; CB indices were highest from ca. 1971 to 1991, whereas SNE indices were high from ca. 1995 to 2005. Wetested for effects of climatic, environmental, biological, and fishing-related variables that have been documented or hypothesized to influence stock productivity. Abroad-scale indicator of climate, the Atlantic Multidecadal Oscillation, was the best single predictor of coast-wide recruitment patterns, and had opposing effects on the CB and SNE regions. Underlying mechanisms of spatial and interannual variability in recruitment likely derive from interactions among climatology, larval transport, adult menhaden distribution, and habitat suitability. The identified regional patterns and climatic effects have implications for the stock assessment of Atlantic menhaden, particularly given the geographically constrained nature of the existing fishery and the climatic oscillations characteristic of the coastal ocean
A controlled trial of natalizumab for relapsing multiple sclerosis.
Background: In patients with multiple sclerosis, inflammatory brain lesions appear to arise from autoimmune responses involving activated lymphocytes and monocytes. The glycoprotein (alpha)(sub 4) integrin is expressed on the surface of these cells and plays a critical part in their adhesion to the vascular endothelium and migration into the parenchyma. Natalizumab is an (alpha)(sub 4) integrin antagonist that reduced the development of brain lesions in experimental models and in a preliminary study of patients with multiple sclerosis.Methods: In a randomized, double-blind trial, we randomly assigned a total of 213 patients with relapsing-remitting or relapsing secondary progressive multiple sclerosis to receive 3 mg of intravenous natalizumab per kilogram of body weight (68 patients), 6 mg per kilogram (74 patients), or placebo (71 patients) every 28 days for 6 months. The primary end point was the number of new brain lesions on monthly gadolinium-enhanced magnetic resonance imaging during the six-month treatment period. Clinical outcomes included relapses and self-reported well-being.Results: There were marked reductions in the mean number of new lesions in both natalizumab groups: 9.6 per patient in the placebo group, as compared with 0.7 in the group given 3 mg of natalizumab per kilogram (P<0.001) and 1.1 in the group given 6 mg of natalizumab per kilogram (P<0.001). Twenty-seven patients in the placebo group had relapses, as compared with 13 in the group given 3 mg of natalizumab per kilogram (P=0.02) and 14 in the group given 6 mg of natalizumab per kilogram (P=0.02). The placebo group reported a slight worsening in well-being (a mean decrease of 1.38 mm on a 100-mm visual-analogue scale), whereas the natalizumab groups reported an improvement (mean increase of 9.49 mm in the group given 3 mg of natalizumab per kilogram and 6.21 mm in the group given 6 mg of natalizumab per kilogram).Conclusions: In a placebo-controlled trial, treatment with natalizumab led to fewer inflammatory brain lesions and fewer relapses over a six-month period in patients with relapsing multiple sclerosis
Improving the psychological evaluation of exercise referral: psychometric properties of the Exercise Referral Quality of Life Scale
There is a growing need to assess the psychological outcomes of exercise referral and the National Institute of Health and Care Excellence has called for the routine assessment of life-quality. However, a quality of life scale specific to the requirements of exercise referral is currently unavailable. Therefore, the aim of this study was to produce a quality of life measure for this purpose. The Exercise Referral Quality of Life Scale is a 22-item measure comprising three domains: mental and physical health, injury pain and illness and physical activity facilitators. Exploratory factor analysis determined the initial factor structure and was subsequently confirmed by confirmatory factor analysis. Additional scale properties were also assessed. The scale contributes to the global need for improved consistent psychological outcome assessment of exercise referral
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