15,496 research outputs found
Binary trees, exploration processes, and an extented Ray--Knight Theorem
We study the bijection between binary Galton--Watson trees in continuous time
and their exploration process, both in the sub- and in the supercritical cases.
We then take the limit over renormalized quantities, as the size of the
population tends to infinity. We thus deduce Delmas' generalization of the
second Ray--Knight theorem
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Revised proposal for encoding the Adlam script in the SMP of the UCS
This is a proposal to encode the Adlam script in the international character encoding standard Unicode. The script was published in Unicode Standard version 9.0 in June 2016. Adlam was used to write Fulani and other African languages in western Africa and neighboring areas. The glyphs have been modified in later versions of the Unicode Standard, so users should consult the latest code charts, which are accessible from
An Upper Bound on the Size of Obstructions for Bounded Linear Rank-Width
We provide a doubly exponential upper bound in on the size of forbidden
pivot-minors for symmetric or skew-symmetric matrices over a fixed finite field
of linear rank-width at most . As a corollary, we obtain a
doubly exponential upper bound in on the size of forbidden vertex-minors
for graphs of linear rank-width at most . This solves an open question
raised by Jeong, Kwon, and Oum [Excluded vertex-minors for graphs of linear
rank-width at most . European J. Combin., 41:242--257, 2014]. We also give a
doubly exponential upper bound in on the size of forbidden minors for
matroids representable over a fixed finite field of path-width at most .
Our basic tool is the pseudo-minor order used by Lagergren [Upper Bounds on
the Size of Obstructions and Interwines, Journal of Combinatorial Theory Series
B, 73:7--40, 1998] to bound the size of forbidden graph minors for bounded
path-width. To adapt this notion into linear rank-width, it is necessary to
well define partial pieces of graphs and merging operations that fit to
pivot-minors. Using the algebraic operations introduced by Courcelle and
Kant\'e, and then extended to (skew-)symmetric matrices by Kant\'e and Rao, we
define boundaried -labelled graphs and prove similar structure theorems for
pivot-minor and linear rank-width.Comment: 28 pages, 1 figur
Fast exact algorithms for some connectivity problems parametrized by clique-width
Given a clique-width -expression of a graph , we provide time algorithms for connectivity constraints on locally checkable properties
such as Node-Weighted Steiner Tree, Connected Dominating Set, or Connected
Vertex Cover. We also propose a time algorithm for Feedback
Vertex Set. The best running times for all the considered cases were either
or worse
Host-feeding patterns of Aedes (Aedimorphus) vexans arabiensis, a Rift Valley Fever virus vector in the Ferlo pastoral ecosystem of Senegal
Background: Host-vector contact is a key factor in vectorial capacity assessment and thus the transmission of mosquito-borne viruses such as Rift Valley Fever (RVF), an emerging zoonotic disease of interest in West Africa. The knowledge of the host-feeding patterns of vector species constitutes a key element in the assessment of their epidemiological importance in a given environment. The aim of this work was to identify the blood meal origins of the mosquito Aedes vexans arabiensis, the main vector of RVF virus in the Ferlo pastoral ecosystem of Senegal. Methodology/principal findings: Engorged female mosquitoes were collected in Younoufe´re´ in the pastoral ecosystem in the Ferlo region during the 2014 rainy season. CO2-baited CDC light traps were set at six points for two consecutive nights every month from July to November. Domestic animals present around traps were identified and counted for each trapping session. Blood meal sources of engorged mosquitoes were identified using a vertebrate-specific multiplexed primer set based on cytochrome b. Blood meal sources were successfully identified for 319 out of 416 blood-fed females (76.68%), of which 163 (51.1%) were single meals, 146 (45.77%) mixed meals from two different hosts and 10 (3.13%) mixed meals from three different hosts. Aedes vexans arabiensis fed preferentially on mammals especially on horse compared to other hosts (FR = 46.83). Proportions of single and mixed meals showed significant temporal and spatial variations according to the availability of the hosts. Conclusion: Aedes vexans arabiensis shows an opportunistic feeding behavior depending on the host availability. This species fed preferentially on mammals especially on horses (primary hosts) and ruminants (secondary hosts)
A Polynomial Delay Algorithm for Enumerating Minimal Dominating Sets in Chordal Graphs
An output-polynomial algorithm for the listing of minimal dominating sets in
graphs is a challenging open problem and is known to be equivalent to the
well-known Transversal problem which asks for an output-polynomial algorithm
for listing the set of minimal hitting sets in hypergraphs. We give a
polynomial delay algorithm to list the set of minimal dominating sets in
chordal graphs, an important and well-studied graph class where such an
algorithm was open for a while.Comment: 13 pages, 1 figure, submitte
Activity report: Monitoring Outcome of Climate-Smart Agriculture in Kaffrine ClimateSmart Village, Senegal
A Climate-Smart Village (CSV) monitoring survey was carried out in Senegal from 14 to 24 November, 2019 by CCAFS WA and CCAFS/CIAT team. Prior to the survey, a one-week training workshop was organized in Kaffrine, from 8 to 13 November 2019 to build the capacities of the local implementation team. The main objective of the CSV monitoring was to assess farmers’ adoption/implementation of Climate-Smart Agricultural (CSA) practices and technologies over the last 12 months and the perceived effects of their implementation on: food security and diversity, crops productivity and income, adaptive capacity and gender aspects (labour, participation in decision making, access/control over generated resources). Seven promising CSA options were considered. Those options included: tree planting, farmer managed natural regeneration, drought tolerant improved varieties of millet, maize or groundnut , reduced tillage, manure use combined with microdose of inorganic fertilizer of NPK and urea, microdose of inorganic fertilizer of NPK and urea and organic fertilizer only (manure, compost). The CSV monitoring targeted two adult persons of opposite sex involved in on-farm activities from a sample of 191 household located in ten villages within the Kaffrine CSV site. The surveyed villages included: Fass Sy (01), Mbane (02), Touba Taba (03), Toune Mosquée (04), Medina Ndiognick (05), Ngouye (06), Ndamboul Mboul (07), Touba Keur Cheikh (08), Djida (09), Daga-Birame (10). Households from Daga-Birame are direct beneficiaries of the CCAFS led CSV activities while the ones located in the other villages are
considered non-beneficiaries or “additional”. The monitoring survey covered 378 individual farmers: 191 males and 187 females
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Neonatal azithromycin administration to prevent infant mortality: study protocol for a randomised controlled trial.
IntroductionBiannual mass azithromycin distribution to children aged 1-59 months has been shown to reduce all-cause mortality. Children under 28 days of age were not treated in studies evaluating mass azithromycin distribution for child mortality due to concerns related to infantile hypertrophic pyloric stenosis (IHPS). Here, we report the design of a randomised controlled trial to evaluate the efficacy and safety of administration of a single dose of oral azithromycin during the neonatal period.Methods and analysisThe Nouveaux-nés et Azithromycine: une Innovation dans le Traitement des Enfants (NAITRE) study is a double-masked randomised placebo-controlled trial designed to evaluate the efficacy of a single dose of azithromycin (20 mg/kg) for the prevention of child mortality. Newborns (n=21 712) aged 8-27 days weighing at least 2500 g are 1:1 randomised to a single, directly observed, oral dose of azithromycin or matching placebo. Participants are followed weekly for 3 weeks after treatment to screen for adverse events, including IHPS. The primary outcome is all-cause mortality at the 6-month study visit.Ethics and disseminationThis study was approved by the Institutional Review Boards at the University of California, San Francisco in San Francisco, USA (Protocol #18-25027) and the Comité National d'Ethique pour la Recherche in Ouagadougou, Burkina Faso (Protocol #2018-10-123). The findings of this trial will be presented at local, regional and international meetings and published in open access peer-reviewed journals.Trial registration numberNCT03682653; Pre-results
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