118 research outputs found

    Computing automorphic forms on Shimura curves over fields with arbitrary class number

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    We extend methods of Greenberg and the author to compute in the cohomology of a Shimura curve defined over a totally real field with arbitrary class number. Via the Jacquet-Langlands correspondence, we thereby compute systems of Hecke eigenvalues associated to Hilbert modular forms of arbitrary level over a totally real field of odd degree. We conclude with two examples which illustrate the effectiveness of our algorithms.Comment: 15 pages; final submission to ANTS I

    On the existence of abelian surfaces with everywhere good reduction

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    Let D≤2000D \le 2000 be a positive discriminant such that F=Q(D)F = \mathbf{Q}(\sqrt{D}) has narrow class one, and A/FA/F an abelian surface of GL2{\rm GL}_2-type with everywhere good reduction. Assuming that AA is modular, we show that AA is either an FF-surface or is a base change from Q\mathbf{Q} of an abelian surface BB such that EndQ(B)=Z{\rm End}_{\mathbf{Q}}(B) = \mathbf{Z}, except for D=353,421,1321,1597D = 353, 421, 1321, 1597 and 19971997. In the latter case, we show that there are indeed abelian surfaces with everywhere good reduction over FF for D=353,421D = 353, 421 and 15971597, which are non-isogenous to their Galois conjugates. These are the first known such examples

    An intriguing hyperelliptic Shimura curve quotient of genus 16

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    Let FF be the maximal totally real subfield of Q(ζ32)\mathbf{Q}(\zeta_{32}), the cyclotomic field of 3232nd roots of unity. Let DD be the quaternion algebra over FF ramified exactly at the unique prime above 22 and 7 of the real places of FF. Let O\mathcal{O} be a maximal order in DD, and X0D(1)X_0^D(1) the Shimura curve attached to O\mathcal{O}. Let C=X0D(1)/⟨wD⟩C = X_0^D(1)/\langle w_D \rangle, where wDw_D is the unique Atkin-Lehner involution on X0D(1)X_0^D(1). We show that the curve CC has several striking features. First, it is a hyperelliptic curve of genus 1616, whose hyperelliptic involution is exceptional. Second, there are 3434 Weierstrass points on CC, and exactly half of these points are CM points; they are defined over the Hilbert class field of the unique CM extension E/FE/F of class number 1717 contained in Q(ζ64)\mathbf{Q}(\zeta_{64}), the cyclotomic field of 6464th roots of unity. Third, the normal closure of the field of 22-torsion of the Jacobian of CC is the Harbater field NN, the unique Galois number field N/QN/\mathbf{Q} unramified outside 22 and ∞\infty, with Galois group Gal(N/Q)≃F17=Z/17Z⋊(Z/17Z)×\mathrm{Gal}(N/\mathbf{Q})\simeq F_{17} = \mathbf{Z}/17\mathbf{Z} \rtimes (\mathbf{Z}/17\mathbf{Z})^\times. In fact, the Jacobian Jac(X0D(1))\mathrm{Jac}(X_0^D(1)) has the remarkable property that each of its simple factors has a 22-torsion field whose normal closure is the field NN. Finally, and perhaps the most striking fact about CC is that it is also hyperelliptic over Q\mathbf{Q}

    The association between child Schistosoma spp. infections and morbidity in an irrigated rice region in Mali: a localized study

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    Schistosomiasis is one of the neglected tropical diseases endemic to Mali. There has been insufficient investigation of the morbidity burden in highly endemic irrigated rice areas with the ongoing mass drug administration with praziquantel. In February 2005, a year after an initial mass drug administration in 2004, we performed the first cross-sectional survey of schistosomiasis in the Kokry-Bozo village in the Office du Niger rice irrigation region. In the fourteen years since this survey, there has been almost no research into schistosomiasis morbidity in Mali due to lack of funding. Therefore, the 2005 survey supplies near-baseline data for any future research into the treatment impacts in the area

    Higher Tetanus Toxoid Immunity 2 Years After PsA-TT Introduction in Mali.

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    BACKGROUND: In 2010, mass vaccination with a then-new meningococcal A polysaccharide-tetanus toxoid protein conjugate vaccine (PsA-TT, or MenAfriVac) was undertaken in 1- to 29-year-olds in Bamako, Mali. Whether vaccination with PsA-TT effectively boosts tetanus immunity in a population with heterogeneous baseline tetanus immunity is not known. We assessed the impact of PsA-TT on tetanus toxoid (TT) immunity by quantifying age- and sex-specific immunity prior to and 2 years after introduction. METHODS: Using a household-based, age-stratified design, we randomly selected participants for a prevaccination serological survey in 2010 and a postvaccination survey in 2012. TT immunoglobulin G (IgG) antibodies were quantified and geometric mean concentrations (GMCs) pre- and postvaccination among all age groups targeted for vaccination were compared. The probability of TT IgG levels ≥0.1 IU/mL (indicating short-term protection) and ≥1.0 IU/mL (indicating long-term protection) by age and sex was determined using logistic regression models. RESULTS: Analysis of 793 prevaccination and 800 postvaccination sera indicated that while GMCs were low pre-PsA-TT, significantly higher GMCs in all age-sex strata were observed 2 years after PsA-TT introduction. The percentage with short-term immunity increased from 57.1% to 88.4% (31.3-point increase; 95% confidence interval [CI], 26.6-36.0;, P < .0001) and with long-term immunity increased from 20.0% to 58.5% (38.5-point increase; 95% CI, 33.7-43.3; P < .0001) pre- and postvaccination. CONCLUSIONS: Significantly higher TT immunity was observed among vaccine-targeted age groups up to 2 years after Mali's PsA-TT mass vaccination campaign. Our results, combined with evidence from clinical trials, strongly suggest that conjugate vaccines containing TT such as PsA-TT should be considered bivalent vaccines because of their ability to boost tetanus immunity

    Serological Evaluation of Onchocerciasis and Lymphatic Filariasis Elimination in the Bakoye and Falémé foci, Mali

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    In Mali, ivermectin-based onchocerciasis elimination from the Bakoye and Falémé foci, reported in 2009–2012, was a beacon leading to policy shifting from morbidity control to elimination of transmission (EOT). These foci are also endemic for lymphatic filariasis (LF). In 2007–2016 mass ivermectin plus albendazole administration was implemented. We report Ov16 (onchocerciasis) and Wb123 (LF) seroprevalence after 24–25 years of treatment to evaluate if onchocerciasis EOT and LF elimination as a public health problem (EPHP) have been achieved

    INPUT SELECTION BY EPR-MOGA

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    The growing availability of field data, from information and communication technologies (ICTs) in "smart'' urban infrastructures, allows data modeling to understand complex phenomena and to support management decisions. Among the analyzed phenomena, those related to storm water quality modeling have recently been gaining interest in the scientific literature. Nonetheless, the large amount of available data poses the problem of selecting relevant variables to describe a phenomenon and enable robust data modeling. This paper presents a procedure for the selection of relevant input variables using the multi-objective evolutionary polynomial regression (EPR-MOGA) paradigm. The procedure is based on scrutinizing the explanatory variables that appear inside the set of EPR-MOGA symbolic model expressions of increasing complexity and goodness of fit to target output. The strategy also enables the selection to be validated by engineering judgement. In such context, the multiple case study extension of EPR-MOGA, called MCS-EPR-MOGA, is adopted. The application of the proposed procedure to modeling storm water quality parameters in two French catchments shows that it was able to significantly reduce the number of explanatory variables for successive analyses. Finally, the EPR-MOGA models obtained after the input selection are compared with those obtained by using the same technique without benefitting from input selection and with those obtained in previous works where other data-modeling techniques were used on the same data. The comparison highlights the effectiveness of both EPR-MOGA and the input selection procedure

    Implementing Preventive Chemotherapy through an Integrated National Neglected Tropical Disease Control Program in Mali

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    Neglected tropical diseases (NTDs) are a group of chronic infections that affect the poorest group of the populations in the world. There are currently five major NTDs targeted through mass drug treatment in the affected communities. The drug delivery can be integrated to deliver different drug packages as these NTDs often overlap in distribution. Mali is endemic with all five major NTDs. The integrated national NTD control program was implemented through the primary health care system using the community health center workers and the community drug distributors aiming at long-term sustainability. After a pilot start in three regions in 2007 without prior examples to follow on integrated mass drug administration, treatment for the five targeted NTDs was gradually scaled up and reached all endemic districts by 2009, and annual drug coverage in the targeted population has since been maintained at a high level for each of the five NTDs. Around 10 million people received one or more drug treatments each year since 2009. The country is on the way to meet the national objectives of elimination or control of these diseases. The successes and lessons learned in Mali are valuable assets to other countries looking to start similar programs
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