7,090 research outputs found
The prevalence of occult hepatitis B virus (hbv) infection in a large multi-ethnic haemodialysis cohort.
Haemodialysis patients are at increased risk of exposure to blood borne viruses. To reduce transmission in the UK, all haemodialysis patients are regularly screened, and if susceptible to Hepatitis B virus (HBV) infection, vaccinated
Undp-Gef Grasslands Project: The Tanzania Montane Grasslands Project
The Tanzania Southern Highlands and adjacent Nyika montane grasslands in Malawi form a distinct centre of plant diversity and endemism. The area is characterised by complex geology with old basement mountains and much more recent volcanoes (Mount Rungwe) adjacent to the rift valet faulting with Lakes Malawi (Nyasa) and Rukwa. Lake proximity generates rainfall up to 3,000 mm per annum. The maximum altitude is 3,000 m asl
Heavy metal toxicity as a kill mechanism in impact caused mass extinctions
Heavy metals that are known to be toxic exist in carbonaceous chrondrites at abundances considerably in excess to that of the terrestrial crust. An impactor of relatively undifferentiated cosmic matter would inject into the terrestrial environment large quantities of toxic elements. The abundances of toxic metals found in the Allende CV carbonaceous chondrite and the ratio of meteoritic abundance to crustal abundance are: Cr, 3630 PPM, 30X; Co, 662 PPM, 23X; ni, 13300 PPm, 134X; se, 8.2 PPM, 164X; Os, 0.828 PPM, 166X. The resulting areal density for global dispersal of impactor derived heavy metals and their dilution with terrestrial ejecta are important factors in the determination of the significance of impactor heavy metal toxicity as a kill mechanism in impact caused mass extinctions. A 10 km-diameter asteroid having a density of 3 gram per cu cm would yield a global areal density of impact dispersed chondritic material of 3 kg per square meter. The present areal density of living matter on the terrestrial land surface is 1 kg per square meter. Dilution of impactor material with terrestrial ejecta is determined by energetics, with the mass of ejecta estimated to be in the range of 10 to 100 times that of the mass of the impactor. Because a pelagic impact would be the most likely case, the result would be a heavy metal rainout
Winter visitors to Yellowstone National Park, their value orientations and support for management actions
The idea of a National Park contains a diversity of values and missions. This paper takes a multi-dimensional, context- specific approach to measuring the perceived values of Yellowstone National Park. It is an initial step in recording how perceptions of National Parks are changing over time. Responses of 1064 winter visitors to 24 park value items were factor and cluster analyzed to produce four groups. Examination of the relationship between cluster membership and support / opposition to a variety of management actions showed significant differences for all 19 proposed actions. Groups of visitors with different value orientations showed correspondingly different levels of support for management actions. The National Park Service (and other natural resource agencies) can, therefore, expect to encounter and manage for a diversity of perceived values and conflicting attitudes towards park management and planning
The history, evolution, and future of big data & analytics:A bibliometric analysis of its relationship to performance in organizations
Big data and analytics (BDA) are gaining momentum, particularly in the practitioner world. Research linking BDA to improved organizational performance seems scarce and widely dispersed though, with the majority focused on specific domains and/or macro-level relationships. In order to synthesize past research and advance knowledge of the potential organizational value of BDA, the authors obtained a data set of 327 primary studies and 1252 secondary cited papers. This paper reviews this body of research, using three bibliometric methods. First, it elucidates its intellectual foundations via co-citation analysis. Second, it visualizes the historical evolution of BDA and performance research and its substreams through algorithmic historiography. Third, it provides insights into the field's potential evolution via bibliographic coupling. The results reveal that the academic attention for the BDA-performance link has been increasing rapidly. The study uncovered ten research clusters that form the field's foundation. While research seems to have evolved following two main, isolated streams, the past decade has witnessed more cross-disciplinary collaborations. Moreover, the study identified several research topics undergoing focused development, including financial and customer risk management, text mining and evolutionary algorithms. The review concludes with a discussion of the implications for different functional management domains and the gaps for both research and practice.</p
High Retention of Minority and International Faculty through a Formal Mentoring Program
In these economic times, retention of new faculty, particularly minority and international faculty, is a high priority. In this study, retention of new faculty from 2006 to 2013 was compared for participants and nonparticipants in a formal mentoring program. Retention was 92% for participating faculty and 58% for nonparticipating new faculty. For African American faculty, retention was 86% for participating and 56% for nonparticipating. Participating international faculty were retained at 100% and nonparticipating at 61%. The results indicate that mentoring programs including both individual and group mentoring provide a supportive community and self validation to new faculty, leading to high retention rates
Testing the recovery of stellar rotation signals from Kepler light curves using a blind hare-and-hounds exercise
We present the results of a blind exercise to test the recoverability of
stellar rotation and differential rotation in Kepler light curves. The
simulated light curves lasted 1000 days and included activity cycles, Sun-like
butterfly patterns, differential rotation and spot evolution. The range of
rotation periods, activity levels and spot lifetime were chosen to be
representative of the Kepler data of solar like stars. Of the 1000 simulated
light curves, 770 were injected into actual quiescent Kepler light curves to
simulate Kepler noise. The test also included five 1000-day segments of the
Sun's total irradiance variations at different points in the Sun's activity
cycle.
Five teams took part in the blind exercise, plus two teams who participated
after the content of the light curves had been released. The methods used
included Lomb-Scargle periodograms and variants thereof, auto-correlation
function, and wavelet-based analyses, plus spot modelling to search for
differential rotation. The results show that the `overall' period is well
recovered for stars exhibiting low and moderate activity levels. Most teams
reported values within 10% of the true value in 70% of the cases. There was,
however, little correlation between the reported and simulated values of the
differential rotation shear, suggesting that differential rotation studies
based on full-disk light curves alone need to be treated with caution, at least
for solar-type stars.
The simulated light curves and associated parameters are available online for
the community to test their own methods.Comment: Accepted for publication in MNRAS. Accepted, 13 April 2015. Received,
26 March 2015; in original form, 9 November 201
Crossing Methodological Boundaries: Assessing Visitor Motivations and Support for Management Actions at Yellowstone National Park Using Quantitative and Qualitative Research Approaches
Winter use of Yellowstone National Park has given rise to a complex of management issues, including rapid growth in recreation demand, environmental impacts of snowmobiling, and a string of litigation against the National Park Service (NPS) designed to both protect park resources and maintain public access (Sacklin et al. 2000). The intertwined character of these problems suggests that none can be resolved independently of the other, that policy must be comprehensive in nature, and that many sources of knowledge may be required to effect their resolution
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