641 research outputs found

    A generic approach for the development of short-term predictions of Escherichia coli and biotoxins in shellfish

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    Microbiological contamination or elevated marine biotoxin concentrations within shellfish can result in temporary closure of shellfish aquaculture harvesting, leading to financial loss for the aquaculture business and a potential reduction in consumer confidence in shellfish products. We present a method for predicting short-term variations in shellfish concentrations of Escherichia coli and biotoxin (okadaic acid and its derivates dinophysistoxins and pectenotoxins). The approach was evaluated for 2 contrasting shellfish harvesting areas. Through a meta-data analysis and using environmental data in situ, satellite observations and meteorological nowcasts and forecasts), key environmental drivers were identified and used to develop models to predict E. coli and biotoxin concentrations within shellfish. Models were trained and evaluated using independent datasets, and the best models were identified based on the model exhibiting the lowest root mean square error. The best biotoxin model was able to provide 1 wk forecasts with an accuracy of 86%, a 0% false positive rate and a 0% false discovery rate (n = 78 observations) when used to predict the closure of shellfish beds due to biotoxin. The best E. coli models were used to predict the European hygiene classification of the shellfish beds to an accuracy of 99% (n = 107 observations) and 98% (n = 63 observations) for a bay (St Austell Bay) and an estuary (Turnaware Bar), respectively. This generic approach enables high accuracy short-term farm-specific forecasts, based on readily accessible environmental data and observations

    Vitamin C partially attenuates male reproductive deficits in hyperglycemic rats

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    <p>Abstract</p> <p>Background</p> <p>Hyperglycemia can impair the male reproductive system in experimental animals and in men during reproductive age. Studies have shown that vitamin C has some good effects on male reproductive system, and therefore vitamin C treatment could attenuate the dysfunctions in this system caused by hyperglycemia. Thus, the objective of this work was to evaluate whether vitamin C treatment could attenuate reproductive dysfunctions in hyperglycemic male rats.</p> <p>Methods</p> <p>Adult male rats were divided into 3 groups: a normoglycemic (n = 10) and two hyperglycemic (that received a single dose of streptozotocin - 40 mg/kg BW). The two last groups (n = 10 per group) were divided into: hyperglycemic control (Hy) and hyperglycemic + 150 mg of vitamin C (HyC), by gavage during 30 consecutive days. The normoglycemic and hyperglycemic control groups received the vehicle (water). The first day after the treatment, the rats were anesthetized and killed to evaluate oxidative stress biomarkers (TBARS, SOD, GSHt and GSH-Px) in the erythrocytes, body and reproductive organ weights, sperm parameters, plasma hormone levels (FSH, LH and testosterone), testicular and epididymal histo-morphometry and histopathology.</p> <p>Results</p> <p>Compared with the normoglycemic animals, hyperglycemic control rats showed reduced weight of the body and reproductive organ but testis weight was maintained. It was also observed reduction of testosterone and LH levels, seminiferous tubular diameter, sperm motility and sperm counts in the epididymis. In addition, there was an increase in morphological abnormalities on spermatozoa as well as in oxidative stress level. Vitamin C reduced the oxidative stress level, diminished the number of abnormal sperm, and increased testosterone and LH levels and seminiferous tubular diameter but did not show improvement of sperm motility in relation to the hyperglycemic control group. Hyperglycemia caused a rearrangement in the epididymal tissue components (stroma, ephitelium and lumen) as demonstrated by the stereological analysis results. However, this alteration was partially prevented by vitamin C treatment.</p> <p>Conclusions</p> <p>We conclude that vitamin C partially attenuated some male reproductive system dysfunctions in hyperglycemic rats.</p

    Autonomy of Nations and Indigenous Peoples and the Environmental Release of Genetically Engineered Animals with Gene Drives

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    This article contends that the environmental release of genetically engineered (GE) animals with heritable traits that are patented will present a challenge to the efforts of nations and indigenous peoples to engage in self‐determination. The environmental release of such animals has been proposed on the grounds that they could function as public health tools or as solutions to the problem of agricultural insect pests. This article brings into focus two political‐economic‐legal problems that would arise with the environmental release of such organisms. To address those challenges, it is proposed that nations considering the environmental release of GE animals must take into account the underlying circumstances and policy failures that motivate arguments for the use of the modified animals. Moreover, countries must recognize that the UN International Covenant on Civil and Political Rights and the UN International Covenant on Economic, Social and Cultural Rights place on them an obligation to ensure that GE animals with patented heritable traits are not released without the substantive consent of the nations or indigenous peoples that could be affected

    Possible Race and Gender Divergence in Association of Genetic Variations with Plasma von Willebrand Factor: A Study of ARIC and 1000 Genome Cohorts

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    The synthesis, secretion and clearance of von Willebrand factor (VWF) are regulated by genetic variations in coding and promoter regions of the VWF gene. We have previously identified 19 single nucleotide polymorphisms (SNPs), primarily in introns that are associated with VWF antigen levels in subjects of European descent. In this study, we conducted race by gender analyses to compare the association of VWF SNPs with VWF antigen among 10,434 healthy Americans of European (EA) or African (AA) descent from the Atherosclerosis Risk in Communities (ARIC) study. Among 75 SNPs analyzed, 13 and 10 SNPs were associated with VWF antigen levels in EA male and EA female subjects, respectively. However, only one SNP (RS1063857) was significantly associated with VWF antigen in AA females and none was in AA males. Haplotype analysis of the ARIC samples and studying racial diversities in the VWF gene from the 1000 genomes database suggest a greater degree of variations in the VWF gene in AA subjects as compared to EA subjects. Together, these data suggest potential race and gender divergence in regulating VWF expression by genetic variations

    In Search of Critically Endangered Species: The Current Situation of Two Tiny Salamander Species in the Neotropical Mountains of Mexico

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    Worldwide, one in every three species of amphibian is endangered, 39 species have gone extinct in the last 500 years and another 130 species are suspected to have gone extinct in recent decades. Of the amphibians, salamanders have the highest portion of their species in one of the risk categories, even higher than the frogs. To date there have been few studies that have used recent field data to examine the status of populations of endangered salamanders. In this study we evaluate the current situation of two tiny salamanders, Parvimolge townsendi and Thorius pennatulus, both of which are distributed at intermediate elevations in the mountains of the northern Neotropics and are considered to be critically endangered; the first has been proposed as possibly extinct. By carrying out exhaustive surveys in both historical and potentially suitable sites for these two species, we evaluated their abundance and the characteristics of their habitats, and we estimated their potential geographic distribution. We visited 22 sites, investing 672 person-hours of sampling effort in the surveys, and found 201 P. townsendi salamanders in 11 sites and only 13 T. pennatulus salamanders in 5 sites. Both species were preferentially found in cloud forest fragments that were well conserved or only moderately transformed, and some of the salamanders were found in shade coffee plantations. The potential distribution area of both species is markedly fragmented and we estimate that it has decreased by more than 48%. The results of this study highlight the importance of carrying out exhaustive, systematic field surveys to obtain accurate information about the current situation of critically endangered species, and help us better understand the crisis that amphibians are facing worldwide

    Determinants of career aspirations of medical students in southern China

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    <p>Abstract</p> <p>Background</p> <p>With recent changes in both the Chinese medical system and compensation of medical doctors, the career aspirations of Chinese medical students have become more diverse. Shantou University Medical College has conducted evaluations and instituted programs to enhance student preparedness to enter a variety of medical careers.</p> <p>Methods</p> <p>A survey was conducted with 85 students to evaluate medical career aspirations and their association with family background, personal skills, English language proficiency, and interest in biomedical research, which were considered as possible factors affecting their career interest.</p> <p>Results</p> <p>Chinese students aspire to traditional as well as nontraditional medical careers. A significant minority of students are now interested in nontraditional careers such as medical teaching or research. However, poor proficiency in the English language and lack of computer skills may limit their academic and career opportunities.</p> <p>Conclusion</p> <p>Career aspirations have changed among medical undergraduates. Although many wish to pursue a traditional clinical doctor career, many are interested in research and teaching careers. Factors such as family background, personal characteristics, school mentoring, and extracurricular support may play a role.</p

    Localization and detection of visual stimuli in monkeys with pulvinar lesions

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    Since the pulvinar receives a major ascending projection of the superior colliculus, pulvinar lesions might produce behavioral impairments resembling those that follow colliculus lesions. To test this possibility, we examined the effect of pulvinar lesions in monkeys on the localization and detection of brief light flashes, a task in which monkeys with colliculus lesions are severely impaired. Some of the pulvinar-lesioned monkeys showed localization impairments similar to those in monkeys with colliculus lesions. However, histological analyses of the lesions suggested that these deficits were related not to the pulvinar damage per se, but rather to interruption of corticotectal fibers that pass through the pulvinar. We conclude that the pulvinar is not critical for the ability to locate and detect brief visual stimuli.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46551/1/221_2004_Article_BF00238622.pd
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