575 research outputs found

    Western North Atlantic Shark-Fishery Management Problems and Informational Requirements

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    The Mid-Atlantic Fishery Management Council (Council) has primary responsibility for the development ofihe Western North Atlantic Shark Fishery Management Plan (FMP). Currently, there is a consensus among the five East Coast Councils that an FMP for sharks should be prepared. The current concerns focus on many of the same issues that were germane a decade ago when a shark FMP was initiated and then halted mainly because of inadequate information. These issues include 1) an expanded, nondiscriminant, commercial longline fishery ; (2) an existing and rapidly expanding recreational fishery; (3) concern for the extensive waste which occurs from both recreational and commercial activities (especially the rapidly increasing issue of harvesting sharks for the use ofonly fins); (4) the reproductive strategy (few offspring, late maturation , and slow growth rates) of many species; and (5) realization that increased fishing pressure on specific shark species generally results in overfishing. Essential information for stock assessment is lacking for sharks and thus management is severely handicapped. Critical data needs include: valid growth information, stock delineation, documentation of the catch by species, samples of the population size structure, mortality estimates, independent indices of population abundance through time, and documentation of all (U.S. and other nationals) user groups both recreational and commercial . Data are particularly sparse for foreign fisheries which have expanded outside U .S. controlled waters, and which could be harvesting the same stocks of sharks.https://scholarworks.wm.edu/vimsbooks/1040/thumbnail.jp

    Seasonal availability and distribution of benthic fishes of Chesapeake Bight

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    In considering the potential for expanding the Middle Atlantic fishery, Virginia Institute of Marine Science estimated the seasonal distribution and availability of benthic fishes on the 15,000 square miles of continental shelf between Cape Hatteras and Cape May. The survey, which started in the winter of 1966 and continued through the winter of 1968, was conducted in two phases. The ·work in 1966 ·was devoted to determining the seasonal distribution of the various kinds of fishes, especially those which appeared to be under-utilized. For.this work a 45-foot semi-balloon shrimp trawl was employed to make 295 tows which were divided among the four seasons. In the second phase, conducted in 1967 and 1968, the objcctive·was to estimate the quantity of fish potentially available to trawlers, should a market be developed

    A study to explore the use of orbital remote sensing to determine native arid plant distribution

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    The author has identified the following significant results. It is possible to determine, from ERTS imagery, native arid plant distribution. Using techniques of multispectral masking and extensive fieldwork, three native vegetation communities were defined and mapped in the Avra Valley study area. A map was made of the Yuma area with the aid of ground truth correlations between areas of desert pavement visible on ERTS images and unique vegetation types. With the exception of the Yuma soil-vegetation correlation phenomena, only very gross differentiations of desert vegetation communities can be made from ERTS data. Vegetation communities with obvious vegetation density differences such as saguaro-paloverde, creosote bush, and riparian vegetation can be separated on the Avra Valley imagery while more similar communities such as creosote bush and saltbush could not be differentiated. It is suggested that large differences in vegetation density are needed before the signatures of two different vegetation types can be differentiated on ERTS imagery. This is due to the relatively insignificant contribution of vegetation to the total radiometric signature of a given desert scene. Where more detailed information concerning the vegetation of arid regions is required, large scale imagery is appropriate

    Risk factors for death in HIV-infected adult african patients recieving anti-retroviral therapy

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    Objective: To determine risk factors for death in HIV-infected African patients on anti-retroviral therapy (ART).Design: Retrospective Case-control study.Setting: The MOH-USAID-AMPATH Partnership ambulatory HIV-care clinics in western Kenya.Results: Between November 2001 and December 2005 demographic, clinical and laboratory data from 527 deceased and 1054 living patients receiving ART were compared to determine independent risk factors for death. Median age at ART initiation was 38 versus 36 years for the deceased and living patients respectively (p<0.0148). Mediantime from enrollment at AMPATH to initiation of ART was two weeks for both groups while median time on ART was eight weeks for the deceased and fourty two weeks for the living (p<0.0001). Patients with CD4 cell counts <100/mm3 were more likely to die than those with counts >100/mm3 (HR=1.553. 95% CI (1.156, 2.087), p<0.003). Patientsattending rural clinics had threefold higher risk of dying compared to patients attending clinic at a tertiary referral hospital (p<0.0001). Two years after initiating treatment fifty percent of non-adherent patients were alive compared to 75% of adherent patients. Male gender, WHO Stage and haemoglobin level <10 grams% were associated with time to death while age, marital status, educational level, employment status andweight were not.Conclusion: Profoundly immunosuppressed patients were more likely to die early in the course of treatment. Also, patients receiving care in rural clinics were at greater risk of dying than those receiving care in the tertiary referral hospital

    A thoracic surgery clinic dedicated to indeterminate pulmonary nodules: Too many scans and too little pathology?

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    ObjectiveWidespread application of computed tomographic scans has increased detection of asymptomatic pulmonary nodules. A dedicated clinic was established to encourage referral and manage large numbers of patients with such nodules.MethodsPatients were evaluated periodically by a nurse practitioner with surgeon oversight, and follow-up imaging was centralized. Patients were rescanned at intervals on the basis of radiologist recommendation.ResultsA total of 414 patients, 189 male and 225 female with a median age of 60.2 years (20.7–84.1 years), were evaluated since April 2000. Median follow-up was 1.51 years (0–6.65 years). Thirty-seven percent (153/414) were older than 60 years with at least 10 pack-years of tobacco use, whereas 30% (123/414) had never smoked. A total of 286 patients completed at least 2 years of follow-up computed tomographic evaluation. After 2 years, 24.2% (69/286) were deemed in stable condition and were discharged from further follow-up, whereas 22.4% (64/286) of patients were followed up longer than 2 years owing to the development of new nodules. Forty-five percent (127/286) of patients did not complete their recommended follow-up at our clinic. Overall, 3% (13/414) of our patients have been shown to have a malignant tumor. Only 5 patients underwent curative resection of a primary lung cancer.ConclusionIn a population of patients with indeterminate nodules in routine clinical practice, few patients required intervention and few cancers were detected. Although the benefits of a “nodule” clinic may include patient reassurance and convenience to referring physicians, a significant number of patients did not complete their follow-up in our clinic

    Intraspecific Variation in Vertical Habitat Use by Tiger Sharks (Galeocerdo cuvier) in the Western North Atlantic

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    Tiger sharks (Galeocerdo cuvier) are a wide ranging, potentially keystone predator species that display a variety of horizontal movement patterns, making use of coastal and pelagic waters. Far less, however, is known about their vertical movements and use of the water column. We used pop-up satellite archival tags with two data sampling rates (high rate and standard rate tags) to investigate the vertical habitat use and diving behavior of tiger sharks tagged on the Puerto Rico–Virgin Islands platform and off Bermuda between 2008 and 2009. Useable data were received from nine of 14 sharks tagged, tracked over a total of 529 days. Sharks spent the majority of their time making yo-yo dives within the upper 50 m of the water column and considerable time within the upper 5 m of the water column. As a result, sharks typically occupied a narrow daily temperature range (~2°C). Dives to greater than 200 m were common, and all sharks made dives to at least 250 m, with one shark reaching a depth of 828 m. Despite some similarities among individuals, a great deal of intraspecific variability in vertical habit use was observed. Four distinct depth distributions that were not related to tagging location, horizontal movements, sex, or size were detected. In addition, similar depth distributions did not necessitate similar dive patterns among sharks. Recognition of intraspecific variability in habitat use of top predators can be crucial for effective management of these species and for understanding their influence on ecosystem dynamics

    Civil Liberties and Volunteering in Six Former Soviet Union Countries

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    To contribute to the debate as to whether volunteering is an outcome of democratization rather than a driver of it, we analyze how divergent democratization pathways in six countries of the former Soviet Union have led to varied levels of volunteering. Using data from the European Values Study, we find that Latvia, Lithuania, and Estonia—which followed a Europeanization path—have high and increasing levels of civil liberties and volunteering. In Russia and Belarus, following a pre-emption path, civil liberties have remained low and volunteering has declined. Surprisingly, despite the Orange Revolution and increased civil liberties, volunteering rates in Ukraine have also declined. The case of Ukraine indicates that the freedom to participate is not always taken up by citizens. Our findings suggest it is not volunteering that brings civil liberties, but rather that increased civil liberties lead to higher levels of volunteerin

    Increased prevalence of pregnancy and comparative risk of program attrition among individuals starting HIV treatment in East Africa

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    Background The World Health Organization now recommends initiating all pregnant women on life-long antiretroviral therapy (ART), yet there is limited information about the characteristics and program outcomes of pregnant women already on ART in Africa. Our hypothesis was that pregnant women comprised an increasing proportion of those starting ART, and that sub-groups of these women were at higher risk for program attrition. Methods and findings We used the International Epidemiology Databases to Evaluate AIDS- East Africa (IeDEA-EA) to conduct a retrospective cohort study including HIV care and treatment programs in Kenya, Uganda, and Tanzania. The cohort consecutively included HIV-infected individuals 13 years or older starting ART 2004–2014. We examined trends over time in the proportion pregnant, their characteristics and program attrition rates compared to others initiating and already receiving ART. 156,474 HIV-infected individuals (67.0% women) started ART. The proportion of individuals starting ART who were pregnant women rose from 5.3% in 2004 to 12.2% in 2014. Mean CD4 cell counts at ART initiation, weighted for annual program size, increased from 2004 to 2014, led by non-pregnant women (annual increase 20 cells/mm3) and men (17 cells/mm3 annually), with lower rates of change in pregnant women (10 cells/mm3 per year) (p<0.0001). There was no significant difference in the cumulative incidence of program attrition at 6 months among pregnant women starting ART and non-pregnant women. However, healthy pregnant women starting ART (WHO stage 1/2) had a higher rate of attrition rate (9.6%), compared with healthy non-pregnant women (6.5%); in contrast among women with WHO stage 3/4 disease, pregnant women had lower attrition (8.4%) than non-pregnant women (14.4%). Among women who initiated ART when healthy and remained in care for six months, subsequent six-month attrition was slightly higher among pregnant women at ART start (3.5%) compared to those who were not pregnant (2.4%), (absolute difference 1.1%, 95% CI 0.7%-1.5%). Conclusions Pregnant women comprise an increasing proportion of those initiating ART in Africa, and pregnant women starting ART while healthy are at higher risk for program attrition than non-pregnant women. As ART programs further expand access to healthier pregnant women, further studies are needed to better understand the drivers of loss among this high risk group of women to optimize retention
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