10,550 research outputs found
Is the even distribution of insecticide-treated cattle essential for tsetse control? Modelling the impact of baits in heterogeneous environments
Background:
Eliminating Rhodesian sleeping sickness, the zoonotic form of Human African Trypanosomiasis, can be achieved only through interventions against the vectors, species of tsetse (Glossina). The use of insecticide-treated cattle is the most cost-effective method of controlling tsetse but its impact might be compromised by the patchy distribution of livestock. A deterministic simulation model was used to analyse the effects of spatial heterogeneities in habitat and baits (insecticide-treated cattle and targets) on the distribution and abundance of tsetse.
Methodology/Principal Findings:
The simulated area comprised an operational block extending 32 km from an area of good habitat from which tsetse might invade. Within the operational block, habitat comprised good areas mixed with poor ones where survival probabilities and population densities were lower. In good habitat, the natural daily mortalities of adults averaged 6.14% for males and 3.07% for females; the population grew 8.46in a year following a 90% reduction in densities of adults and pupae, but expired when the population density of males was reduced to <0.1/km2; daily movement of adults averaged 249 m for males and 367 m for females. Baits were placed throughout the operational area, or patchily to simulate uneven distributions of cattle and targets. Gaps of 2–3 km between baits were inconsequential provided the average imposed mortality per km2 across the entire operational area was maintained. Leaving gaps 5–7 km wide inside an area where baits killed 10% per day delayed effective control by 4–11 years. Corrective measures that put a few baits within the gaps were more effective than deploying extra baits on the edges.
Conclusions/Significance:
The uneven distribution of cattle within settled areas is unlikely to compromise the impact of insecticide-treated cattle on tsetse. However, where areas of >3 km wide are cattle-free then insecticide-treated targets should be deployed to compensate for the lack of cattle
Management of erectile dysfunction post-radical prostatectomy
© 2015 Saleh et al.Radical prostatectomy is a commonly performed procedure for the treatment of localized prostate cancer. One of the long-term complications is erectile dysfunction. There is little consensus on the optimal management; however, it is agreed that treatment must be prompt to prevent fibrosis and increase oxygenation of penile tissue. It is vital that patient expectations are discussed, a realistic time frame of treatment provided, and treatment started as close to the prostatectomy as possible. Current treatment regimens rely on phosphodiesterase 5 inhibitors as a first-line therapy, with vacuum erection devices and intraurethral suppositories of alprostadil as possible treatment combination options. With nonresponders to these therapies, intracavernosal injections are resorted to. As a final measure, patients undergo the highly invasive penile prosthesis implantation. There is no uniform, objective treatment program for erectile dysfunction post-radical prostatectomy. Management plans are based on poorly conducted and often underpowered studies in combination with physician and patient preferences. They involve the aforementioned drugs and treatment methods in different sequences and doses. Prospective treatments include dietary supplements and gene therapy, which have shown promise with there proposed mechanisms of improving erectile function but are yet to be applied successfully in human patients
TRANSFORMATIONAL LEADERSHIP IN THE ASSOCIATION OF RELATED CHURCHES: A CROSS-SECTIONAL EXAMINATION OF MINISTRY STUDENTS AT SOUTHEASTERN UNIVERSITY REGIONAL CAMPUSES
The purpose of this study was to identify independent programmatic leadership activity variables that showed the most robust correlation to higher transformational leadership scores in ministry students. Recognizing which variables have the strongest correlation to higher transformational leadership scores may help regional campus directors and pastors better understand how to develop future church leaders in their programs. This quantitative study utilized a survey method that addressed six research questions. The Multifactor Leadership Questionnaire (MLQ) served as the instrument. Association of Related Churches (ARC) ministry students located at Southeastern University regional campuses in Florida were the population. Idealized influence-attribution represented the most robust correlate within transformational leadership, the independent variable of GPA had a moderate correlation to higher transformational leadership scores, and the independent variable of leadership courses had a moderate inverse correlation to transactional leadership. Implications of this study include recommendations for future strategies related to developing transformational leaders within ARC regional campuses
Biomarkers: a strategic tool in the assessment of environmental quality of coastal waters
Ecosystems are under the pressure of complex mixtures of contaminants whose effects are not always simple to assess. Biomarkers, acting as early warning signals of the presence of potentially toxic xenobiotics, are useful tools for assessing either exposure to, or the effects of these compounds providing information about the toxicant bioavailability. In fact, it has been argued that a full understanding of ecotoxicological processes must consider an integrated multi-level approach, in which molecular impact is related with higher-order biological consequences at the individual, population and community levels. Monitoring programs should make use of this tool to link contaminants and ecological responses fulfilling strategies like those launched by OSPAR (Commissions of Oslo and Paris) Convention on the protection of the marine environment of the North-East Atlantic and the International Council for the Exploration of the Sea (ICES). An overview of the work done in the past few years using biomarkers as in situ tools for pollution assessment in Portuguese coastal waters is presented as a contribution to the set up of a biomonitoring program for the Portuguese coastal zone. Considering the data set available the biomonitoring proposal should include the analysis of biomarkers and effects at individual levels. The aim of the program will include a spatial and temporal characterization of the biomarkers acetyl-cholinesterase, metallothioneins, DNA damage, adenylate energy charge and scope-for-growth levels. The investigation of the spatial variation of biomarkers is crucial to define sites for long term monitoring, which will be integrated with a chemical monitoring program. This framework will be a major contribution to the implementation of a national database for the use of biomarkers along the Portuguese coast.info:eu-repo/semantics/publishedVersio
Highlights from PHENIX II: Exploring the QCD medium
Much of the present experimental effort at RHIC is now directed towards
understanding the properties of the hot and dense colored medium created in A+A
collisions. Recent results from PHENIX on the dynamical evolution of the medium
and its response to high momentum probes are presented, and their impact on our
overall understanding of heavy-ion collisions is discussed.Comment: 8 pages, 6 figures - To appear in the conference proceedings for
Quark Matter 2009, March 30 - April 4, Knoxville, Tennessee. Revised versio
Dynamic spin response of a strongly interacting Fermi gas
We present an experimental investigation of the dynamic spin response of a
strongly interacting Fermi gas using Bragg spectroscopy. By varying the
detuning of the Bragg lasers, we show that it is possible to measure the
response in the spin and density channels separately. At low Bragg energies,
the spin response is suppressed due to pairing, whereas the density response is
enhanced. These experiments provide the first independent measurements of the
spin-parallel and spin-antiparallel dynamic and static structure factors and
open the way to a complete study of the structure factors at any momentum. At
high momentum the spin-antiparallel dynamic structure factor displays a
universal high frequency tail, proportional to , where is the probe energy.Comment: Replaced with final versio
A proposal for a different chi-square function for Poisson distributions
We obtain an approximate Gaussian distribution from a Poisson distribution
after doing a change of variable. A new chi-square function is obtained which
can be used for parameter estimations and goodness-of-fit testing when
adjusting curves to histograms. Since the new distribution is approximately
Gaussian we can use it even when the bin contents are small. The corresponding
chi-square function can be used for curve fitting. This chi-square function is
simple to implement and presents a fast convergence of the parameters to the
correct value, especially for the parameters associated with the width of the
fitted curve. We present a Monte Carlo comparative study of the fitting method
introduced here and two other methods for three types of curves: Gaussian,
Breit-Wigner and Moyal, when each bin content obeys a Poisson distribution. It
is also shown that the new method and the other two converge to the same result
when the number of events increasesComment: 27 pages, 13 figure
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