ESTIMATING GENDER DIFFERENCES IN AGRICULTURAL PRODUCTIVITY: BIASES DUE TO OMISSION OF GENDER-INFLUENCED VARIABLES AND ENDOGENEITY OF REGRESSORS

This study evaluates managerial differences between men and women and assesses the degree of bias introduced by omission of gender-influenced variables and ignoring the endogeneity of farmer characteristics and input levels. The results also give insight to improving research methods for isolating the gender impact on productivity.Labor and Human Capital, Productivity Analysis,

Barium fluoride whispering-gallery-mode disk-resonator with one billion quality-factor

We demonstrate a monolithic optical whispering gallery mode resonator fabricated with barium fluoride (BaF$_2$) with an ultra-high quality ($Q$) factor above $10^9$ at $1550$ nm, and measured with both the linewidth and cavity-ring-down methods. Vertical scanning optical profilometry shows that the root mean square surface roughness of $2$ nm is achieved for our mm-size disk. To the best of our knowledge, we show for the first time that one billion $Q$-factor is achievable by precision polishing in relatively soft crystals with mohs hardness of ~$3$. We show that complex thermo-optical dynamics can take place in these resonators. Beside usual applications in nonlinear optics and microwave photonics, high energy particle scintillation detection utilizing monolithic BaF$_2$ resonators potentially becomes feasible

Effect of Nitrogen Fertilizer Dose and Application Timing on Yield and Nitrogen Use Efficiency of Irrigated Hybrid Rice under Semi-Arid Conditions

Nitrogen fertilizer is the major input in rice production and the optimum rate and application timing management assure profitability and sustainability of the production system. This study aims to investigate hybrid rice response to different nitrogen fertilizer levels and the timing of application and quantify hybrid rice nitrogen use efficiency. Field experiments were conducted during the dry and the wet seasons 2016 at the research station of Africa Rice at Ndiaye in Senegal. Six nitrogen rates (0, 60, 90, 120, 150 and 180 kg N/ha) and three hybrid rice varieties (AR031H, AR032H, AR033H) and one inbred variety (Sahel108) and two nitrogen fertilizer application timings (three split and four split) were combined within a split-split plot design. The results showed significant effect of nitrogen rate and timing on rice grain yield that varied from 4.10 to 11.58 tons/ha and most the yield components. Rice grain yield exhibited curvilinear relationship with the applied nitrogen rates during the dry season under both nitrogen application timings and a linear relationship during the wet season under three splits. Nitrogen rate of 150 kg/ha was revealed optimum with best performance achieved by the Hybrid rice AR033H. Hybrid rice genotypes achieved greater nitrogen use efficiency compared to the inbred rice Sahel108. Hence, hybrid rice genotypes, and nitrogen rate of 150 kg/ha applied in four splits could be recommended to improve rice production and food security for achieving self-sufficiency in rice as targeted by Senegal and the neighboring countries

Epidémiologie de la peste des petits ruminants (PPR) et de la peste bovine au Mali : enquêtes sérologiques

Dans le cadre de l'épidémiosurveillance de la peste bovine au Mali, une enquête sérologique a été conduite dans 58 troupeaux de petits ruminants. Sur 567 sérums analysés pour la détection des anticorps anti-peste bovine, deux seulement se sont révélés positifs. Ils proviennent de deux animaux âgés de plus de 6 ans et donc probablement contaminés lors de la dernière épidémie de peste bovine survenue en 1986. Il est probable que le virus bovipestique ne circule plus au Mali depuis cette date. En revanche, l'infection des chèvres et des moutons avec le virus de la peste des petits ruminants semble être importante : 74 p. 100 des troupeaux ont déjà été contaminés. La prévalence de l'infection individuelle est de 32 p. 100. Une enquête sérologique similaire conduite chez 450 bovins dépourvus d'anticorps anti-peste bovine a montré que 1,78 p. 100 de ces animaux a été en contact avec le virus PPR. Avec un taux si faible d'infection de bovins, le virus PPR n'a probablement pas d'incidence sur l'épidémiologie de la peste bovine au Mali. (Résumé d'auteur

Cetacean research in Senegal 1995-97, an overview. Scientific Committee document SC/49/SM10, International Whaling Commission, Bournemouth, UK

Historically Senegal is the West-African nation with the best kept faunistical records for cetaceans. We found verifiable evidence for at least 18 species, but limited life history data. Quantified information on interactions with soaring coastal fisheries is wanting. Here we present preliminary results of recent field work in central and central-south Senegal, which aim was to help design a long-term research plan with Senegalese scientists, offer training and reinitiate data collecting.With limited monitoring we encountered evidence of dolphin by-catches but no wide-spread directed dolphin fishery. However the presence of tell-tale conditions including spreading acceptance for consumption of dolphin meat and indications of overexploitation of some fish stocks are known warning signs. Future efforts should cover larger areas and generally be more intensive. Three carcasses of Atlantic hump-backed dolphin Sousa teuszii found on Sangomar island had rope tied around the tailstock. Fishermen at Djifer and Joal-Fadiouth confirmed regular incidental takes and landings. In the Siné-Saloum delta, inshore S. teuszii and T. truncatus are probably the most affected species. Senegal’s EEZ waters support large industrial fisheries which may constitute an additional source of by-caught small cetaceans. We here document 21 new specimen records and a series of sightings. Dolphins occurring in the Casamance river and upstream in the salt-water canals of the Saloum delta are identified as T. truncatus

Outsourcing selective maintenance problem in failure prone multi-component systems

In many industrial settings, there are systems designed to perform consecutive missions interspersed with finite breaks during which only a set of component repairs can be carried out due to limited time, budget, or resources. The decision maker then has to decide which components to repair in order to guarantee a given performance level. This is known as the selective maintenance problem (SMP). This paper introduces a new variant of the SMP by specifically taking into account the maintenance outsourcing alternative. A novel integrated non-linear programming formulation where both the in-house and outsourcing maintenance alternatives are accounted for is developed and optimally solved. The effect of the outsourcing alternative on maintenance decisions is investigated through numerical experiments. The overall results obtained demonstrate the validity of the proposed approach. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved