322 research outputs found

    The Increasing Burden of Imported Chronic Hepatitis B — United States, 1974–2008

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    Without intervention, up to 25% of individuals chronically infected with hepatitis B virus (HBV) die of late complications, including cirrhosis and liver cancer. The United States, which in 1991 implemented a strategy to eliminate HBV transmission through universal immunization, is a country of low prevalence. Approximately 3,000-5,000 U.S.-acquired cases of chronic hepatitis B have occurred annually since 2001. Many more chronically infected persons migrate to the United States yearly from countries of higher prevalence. Although early identification of chronic HBV infection can reduce the likelihood of transmission and late complications, immigrants are not routinely screened for HBV infection during or after immigration.To estimate the number of imported cases of chronic hepatitis B, we multiplied country-specific prevalence estimates by the yearly number of immigrants from each country during 1974-2008.During 1974-2008, 27.9 million immigrants entered the U.S. Sixty-three percent were born in countries of intermediate or high chronic hepatitis B prevalence (range 2%-31%). On average, an estimated 53,800 chronic hepatitis B cases were imported to the U.S. yearly from 2004 through 2008. The Philippines, China, and Vietnam contributed the most imported cases (13.4%, 12.5%, and 11.0%, respectively). Imported cases increased from an estimated low of 105,750 during the period 1974-1977 to a high of 268,800 in 2004-2008.Imported chronic hepatitis B cases account for approximately 95% of new U.S. cases. Earlier case identification and management of infected immigrants would strengthen the U.S. strategy to eliminate HBV transmission, and could delay disease progression and prevent some deaths among new Americans

    Management implications of the Macquarie Island trophic cascade revisited: a reply to Dowding et al.

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    1. The management of non-indigenous species is not without its complications. In Bergstrom et al.'s (2009) study, we demonstrated that feral cats Felis catus on sub-Antarctic Macquarie Island were exerting top-downcontrol on the feral rabbit Oryctolagus cuniculus population, and that the eradication of the cats led to a substantial increase in rabbit numbers and an associated trophic cascade. 2. Dowding et al. (2009) claim our modelling was flawed for various reasons, but primarily that a reduction in the application of the rabbit control agent, Myxoma virus, coinciding with cat removal, was a major driver of rabbit population release. 3. We explore this proposition (as well as others) by examining rates of Myxoma viral release between 1991 and 2006 (with an attenuation factor for the years, 2003-2006) in association with presence/absence of cats against two estimates of rabbit population size. Myxoma viral release was a significant factor in the lower estimates of rabbit population, but the effect was small, and was not significant for higher rabbit population estimates. By contrast, the presence or absence of cats remained highly significant for both estimates. 4. Synthesis and applications. We re-affirm our position that top-down control of rabbit numbers by cats, prior to their eradication, was occurring on Macquarie Island. Nonetheless, we agree with Dowding et al. (2009) that systems with multiple invasive species represent complex situations that require careful scrutiny. Such scrutiny should occur in advance of, during, and following management interventions.Centre of Excellence for Invasion Biolog

    Indirect effects of invasive species removal devastate World Heritage Island.

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    1. Owing to the detrimental impacts of invasive alien species, their control is often a priority for conservation management. Whereas the potential for unforeseen consequences of management is recognized, their associated complexity and costs are less widely appreciated. 2. We demonstrate that theoretically plausible trophic cascades associated with invasive species removal not only take place in reality, but can also result in rapid and drastic landscape-wide changes to ecosystems. 3. Using a combination of population data from of an invasive herbivore, plot-scale vegetation analyses, and satellite imagery, we show how a management intervention to eradicate a mesopredator has inadvertently and rapidly precipitated landscape-wide change on sub-Antarctic Macquarie Island. This happened despite the eradication being positioned within an integrated pest management framework. Following eradication of cats Felis catus in 2001, rabbit Oryctolagus cuniculus numbers increased substantially although a control action was in place (Myxoma virus), resulting in island-wideecosystem effects. 4.Synthesis and applications. Our results highlight an important lesson for conservation agencies working to eradicate invasive species globally; that is, risk assessment of management interventions must explicitly consider and plan for their indirect effects, or face substantial subsequent costs. On Macquarie Island, the cost of further conservation action will exceed AU$24 million.Centre of Excellence for Invasion Biolog

    The relation between school leadership from a distributed perspective and teachers' organizational commitment: examining the source of the leadership function

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    Purpose: In this study the relationship between school leadership and teachers’ organizational commitment is examined by taking into account a distributed leadership perspective. The relation between teachers’ organizational commitment and contextual variables of teachers’ perceptions of the quality and the source of the supportive and supervisory leadership function, participative decision making, and cooperation within the leadership team are examined. Research Design: A survey was set up involving 1,522 teachers from 46 large secondary schools in Flanders (Belgium). Because the data in the present study have an inherent hierarchical structure, that is, teachers are nested into schools, hierarchical linear modeling techniques are applied. Findings: The analyses reveal that 9% of the variance in teachers’ organizational commitment is attributable to differences between schools. Teachers’ organizational commitment is mainly related to quality of the supportive leadership, cooperation within the leadership team, and participative decision making. Who performed the supportive leadership function plays only a marginally significant positive role. The quality of the supervisory leadership function and the role of the leadership team members in this function were not significantly related to teachers’ organizational commitment. Conclusions: The implications of the findings are that to promote teachers’ organizational commitment teachers should feel supported by their leadership team and that this leadership team should be characterized by group cohesion, role clarity, and goal orientedness. Recommendations for further research are provided

    A preliminary comparison study of burnout and engagement in performance students in Australia, Poland and the UK

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    While there is a growing body of research concerning the well-being of music students, burnout and engagement remain largely unexplored. Likewise, cross-national variations in approaches to music education, and different educational experiences of men and women may influence burnout and engagement. This preliminary study aimed to inform further research by establishing the levels of, and exploring cross-national and sex differences in burnout and engagement in music performance students at conservatoires in Australia, Poland and the UK (n = 331). Self-reported levels of burnout were, typically, low to moderate. Nevertheless, one in ten students reported symptoms such that they could be classified as burned out. Australian and UK students displayed more burnout than students in Poland, although Australian students reported lower levels of reduced sense of accomplishment than Polish and UK students. Self-reported engagement was, typically, moderate to high. Students in Poland reported higher levels of engagement than those in the UK. Women displayed higher levels of global burnout and emotional/physical exhaustion, while men reported lower levels of reduced sense of accomplishment. Further research on burnout and engagement could build on this investigation to gain a better understanding of their impact and the influence of the educational experience on students’ music-related well-being

    Influenza A(H1N1)pdm09 vaccination policies and coverage in Europe

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    In August 2010 the Vaccine European New Integrated Collaboration Effort (VENICE) project conducted a survey to collect information on influenza A(H1N1) pdm09 vaccination policies and vaccination coverage in the European Union (EU), Norway and Iceland. Of 29 responding countries, 26 organised national pandemic influenza vaccination and one country had recommendations for vaccination but did not have a specific programme. Of the 27 countries with vaccine recommendations, all recommended it for healthcare workers and pregnant women. Twelve countries recommended vaccine for all ages. Six and three countries had recommendations for specific age groups in children and in adults, countries for specific adult age groups. Most countries recommended vaccine for those in new risk groups identified early in the pandemic such as morbid obese and people with neurologic diseases. Two thirds of countries started their vaccination campaigns within a four week period after week 40/2009. The reported vaccination coverage varied between countries from 0.4% to 59% for the entire population (22 countries); 3% to 68% for healthcare workers (13 countries); 0% to 58% for pregnant women (12 countries); 0.2% to 74% for children (12 countries). Most countries identified similar target groups for pandemic vaccine, but substantial variability in vaccination coverage was seen. The recommendations were in accordance with policy advice from the EU Health Security Committee and the World Health Organization

    The relationship between the perception of distributed leadership in secondary schools and teachers' and teacher leaders' job satisfaction and organizational commitment

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    This study investigates the relation between distributed leadership, the cohesion of the leadership team, participative decision-making, context variables, and the organizational commitment and job satisfaction of teachers and teacher leaders. A questionnaire was administered to teachers and teacher leaders (n=1770) from 46 large secondary schools. Multiple regression analyses and path analyses revealed that the study variables explained significant variance in organizational commitment. The degree of explained variance for job satisfaction was considerably lower compared to organizational commitment. Most striking was that the cohesion of the leadership team and the amount of leadership support was strongly related to organizational commitment, and indirectly to job satisfaction. Decentralization of leadership functions was weakly related to organizational commitment and job satisfaction
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