428 research outputs found
EVALUATING A REACTIVE TEST-AND-TREAT PROGRAM FOR SUB-PATENT MALARIA IN MACHA, ZAMBIA: OPTIMAL STRATEGIES TO ACHIEVE ELIMINATION
Background: In Choma District, Southern Province, Zambia, malaria prevalence by rapid diagnostic test (RDT) declined from 8% in 2008 to 1% in 2013. As part of an effort to achieve elimination, the Zambian government implemented a reactive test-and-treat (RTAT) program in parts of Southern Province in 2013. Individuals with confirmed malaria by health workers are followed-up within two weeks of diagnosis. All individuals living in households within 140 meters of the index case are tested with an RDT and treated if positive. This study aimed to optimize the RTAT strategy by characterizing infected individuals missed by both the RDT and the current screening radius.
Methods: Health workers notified the study team of individuals with RDT confirmed malaria. For each study participant, a questionnaire was administered and a blood sample collected. To evaluate the optimal RTAT radius and assess the frequency of sub-patent, RDT negative infections, the radius was expanded to 250 meters and testing of dried blood spot samples by real-time polymerase chain reaction (PCR) was introduced. Spatial-temporal cluster detection was conducted to identify clusters of index households.
Results: From January 2015 to January 2016, 101 index cases were followed-up through the RTAT program. 2504 individuals residing in 394 households were screened. Excluding index cases, parasite prevalence was 2.5% by PCR (53 of 2225) and 1.2% by RDT (26 of 2108). 66% of PCR positive individuals tested negative by RDT. 24 households had a PCR+/RDT- individual. Nearly half of those infected resided within the index case household. No clustering of index house was identified.
Conclusion: The low number of secondary cases indicates a low efficiency of RTAT beyond the index case household in this setting, and the sensitivity of the RDT was too low to be an effective screening tool. Focal drug administration in which all individuals within index case households are treated may be a more efficient approach to achieving malaria elimination in southern Zambia
THE CHANGING SPATIAL EPIDEMIOLOGY OF MALARIA IN THE DEMOCRATIC REPUBLIC OF THE CONGO
Malaria remains a significant public health problem worldwide, and especially in the Democratic Republic of the Congo (DRC), where approximately 12% of global cases occur. Despite this burden, very few national malaria studies have been conducted in the DRC, particularly amongst adults. Because of this, critical questions, such who is at highest risk and where transmission is highest, remain under-studied. This information is needed to tailor interventions to individuals and areas in which they will be most effective. We aimed to fill this gap in the literature using data from the population based, nationally-representative Demographic and Health Surveys (DHS) conducted in the DRC. Using DHS data, we evaluated the status of malaria prevalence amongst adults in the DRC, and determine changes in prevalence over time. We found that the national prevalence is high, approximately 30%, and that the prevalence of patent infections increased from 2.4% in 2007 to 7.5% in 2013. We identified several risk factors for infection, such as traditional housing and decreased within-household net coverage. However, we also found that while uptake of malaria interventions has increased since 2007, use of long-lasting insecticide treated nets (LLIN) and intermittent preventative therapy during pregnancy both remain low. Increasing LLIN use was associated with only a small reduction in prevalence of patent infection, pointing to the need to re-evaluate current malaria control strategies. Overall, this dissertation highlights the high prevalence of infections amongst adults and the need for massively scaled up malaria control efforts. The findings identify individuals and areas that most need attention. These findings will help the DRC Ministry of Health plan future malaria control programs and help ensure that such programs are maximally effective. This dissertation also underscore the importance of studying malaria amongst individuals of all ages.Doctor of Philosoph
The form of morphemes:MEG evidence from masked priming of two Hebrew templates
Studies of lexical access have benefited from comparisons between languages like English, which shows concatenative morphology, and Semitic languages showing non-concatenative morphology of roots and patterns. Morphological decomposition in Semitic has previously been probed using masked priming, originally developed to investigate concatenative morphology. However, studies conducted on Semitic languages have often targeted Semitic-specific questions, such as whether the root and the verbal template prime lexical access. The overall consequence of these studies for our understanding of lexical access remains unclear. In two experiments on Hebrew using MEG, we demonstrate that a verbal form which is orthographically and phonologically indistinguishable from non-verbal forms is primed by other verbs in the same template but not by similar nouns and adjectives. These results suggest that masked priming taps into more than just visual forms but reflects morphological content, even if this content is abstract, showing no distinct orthographic or phonological marking
An Evolutionary Reduction Principle for Mutation Rates at Multiple Loci
A model of mutation rate evolution for multiple loci under arbitrary
selection is analyzed. Results are obtained using techniques from Karlin (1982)
that overcome the weak selection constraints needed for tractability in prior
studies of multilocus event models. A multivariate form of the reduction
principle is found: reduction results at individual loci combine topologically
to produce a surface of mutation rate alterations that are neutral for a new
modifier allele. New mutation rates survive if and only if they fall below this
surface - a generalization of the hyperplane found by Zhivotovsky et al. (1994)
for a multilocus recombination modifier. Increases in mutation rates at some
loci may evolve if compensated for by decreases at other loci. The strength of
selection on the modifier scales in proportion to the number of germline cell
divisions, and increases with the number of loci affected. Loci that do not
make a difference to marginal fitnesses at equilibrium are not subject to the
reduction principle, and under fine tuning of mutation rates would be expected
to have higher mutation rates than loci in mutation-selection balance. Other
results include the nonexistence of 'viability analogous, Hardy-Weinberg'
modifier polymorphisms under multiplicative mutation, and the sufficiency of
average transmission rates to encapsulate the effect of modifier polymorphisms
on the transmission of loci under selection. A conjecture is offered regarding
situations, like recombination in the presence of mutation, that exhibit
departures from the reduction principle. Constraints for tractability are:
tight linkage of all loci, initial fixation at the modifier locus, and mutation
distributions comprising transition probabilities of reversible Markov chains.Comment: v3: Final corrections. v2: Revised title, reworked and expanded
introductory and discussion sections, added corollaries, new results on
modifier polymorphisms, minor corrections. 49 pages, 64 reference
The burden of Malaria in the democratic Republic of the Congo
Despite evidence that older children and adolescents bear the highest burden of malaria, large malaria surveys focus on younger children. We used polymerase chain reaction data from the 2013-2014 Demographic and Health Survey in the Democratic Republic of Congo (including children aged <5 years and adults aged ≥15 years) and a longitudinal study in Kinshasa Province (participants aged 6 months to 98 years) to estimate malaria prevalence across age strata. We fit linear models and estimated prevalences for each age category; adolescents aged 10-14 years had the highest prevalence. We estimate approximately 26 million polymerase chain reaction-detectable infections nationally. Adolescents and older children should be included in surveillance studies
Large infrapatellar ganglionic cyst of the knee fat pad: a case report and review of the literature
<p>Abstract</p> <p>Introduction</p> <p>Large ganglionic cystic formations arising from the infrapatellar fat pad are quite uncommon and only a few are mentioned in the literature. An open excision in these cases is mandatory.</p> <p>Case presentation</p> <p>We report the case of a large infrapatellar fat pad ganglion in a 37-year-old Greek man with chronic knee discomfort. The ganglionic cyst originated from the infrapatellar fat pad and had no intrasynovial extension. The final diagnosis was determined with magnetic resonance imaging of the knee, and the lesion was treated with surgery.</p> <p>Conclusions</p> <p>These lesions are asymptomatic in most cases but often are misdiagnosed as meniscal or ligamentous lesions of the knee joint. Nowadays, the therapeutic trend for such lesions is arthroscopic excision, but when there is a large ganglion, as in this case report, the treatment should be an open and thorough resection. This report is intended mostly but not exclusively for clinical physicians and radiologists.</p
Relationship of fat patterning to coronary artery disease risk in obese adolescents
Fatness and fat patterning of 27 male and 33 female obese adolescents were identified by principal-components analysis of five skinfolds (triceps, subscapular, iliac, abdominal, and thigh). Correlations were computed between the component scores, based on the eigen vectors, and anthropometric and physiological variables. Overall fatness, component I, was highly correlated with all anthropometric and body composition variables. Also, component I significantly correlated with fasting insulin and VO 2 max for both sexes and with basal metabolism and HDL-cholesterol for females and males, respectively. Extremity fat patterning, component II, was poorly correlated with all the anthropometric and physiological variables except diastolic blood pressure for the females. Upper-lower body fat patterning, component III, was correlated with the fewest physiological variables.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37636/1/1330710405_ftp.pd
Quantum walks: a comprehensive review
Quantum walks, the quantum mechanical counterpart of classical random walks,
is an advanced tool for building quantum algorithms that has been recently
shown to constitute a universal model of quantum computation. Quantum walks is
now a solid field of research of quantum computation full of exciting open
problems for physicists, computer scientists, mathematicians and engineers.
In this paper we review theoretical advances on the foundations of both
discrete- and continuous-time quantum walks, together with the role that
randomness plays in quantum walks, the connections between the mathematical
models of coined discrete quantum walks and continuous quantum walks, the
quantumness of quantum walks, a summary of papers published on discrete quantum
walks and entanglement as well as a succinct review of experimental proposals
and realizations of discrete-time quantum walks. Furthermore, we have reviewed
several algorithms based on both discrete- and continuous-time quantum walks as
well as a most important result: the computational universality of both
continuous- and discrete- time quantum walks.Comment: Paper accepted for publication in Quantum Information Processing
Journa
New limits on nucleon decays into invisible channels with the BOREXINO Counting Test Facility
The results of background measurements with the second version of the
BOREXINO Counting Test Facility (CTF-II), installed in the Gran Sasso
Underground Laboratory, were used to obtain limits on the instability of
nucleons, bounded in nuclei, for decays into invisible channels ():
disappearance, decays to neutrinos, etc. The approach consisted of a search for
decays of unstable nuclides resulting from and decays of parents
C, C and O nuclei in the liquid scintillator and the water
shield of the CTF. Due to the extremely low background and the large mass (4.2
ton) of the CTF detector, the most stringent (or competitive) up-to-date
experimental bounds have been established: y, y, y and y, all at 90% C.L.Comment: 22 pages, 3 figures,submitted to Phys.Lett.
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