Phonon Transmission by bcc Sandwich Layers in Fe/Co/Fe and Co/Fe/Co Systems

A calculation of the coherent and ballistic phonon transport via thin nanojunctions between bcc lattices is presented. The model system A/B/A consists of a finite number of bcc (001) atomic layers of an element B sandwiched between two bcc semi-infinite crystal lattices of another element A oriented in the same (001) plane. It is applied to the Fe/Co/Fe nanojunction and to the inverse Co/Fe/Co nanojunction. The theoretical calculations of the ballistic phonon transmission via the nanojunction are carried out using the matching method. The possible experimental measurements of this ballistic transmission in comparison with theoretical results should be a useful probe for the determination of alloying force constants across the interface between two such elements. The full bcc dynamics of this system is under study

The REFANI-N study protocol: a cluster-randomised controlled trial of the effectiveness and cost-effectiveness of early initiation and longer duration of emergency/seasonal unconditional cash transfers for the prevention of acute malnutrition among children, 6-59 months, in Tahoua, Niger.

BACKGROUND: The global burden of acute malnutrition among children remains high, and prevalence rates are highest in humanitarian contexts such as Niger. Unconditional cash transfers are increasingly used to prevent acute malnutrition in emergencies but lack a strong evidence base. In Niger, non-governmental organisations give unconditional cash transfers to the poorest households from June to September; the 'hunger gap'. However, rising admissions to feeding programmes from March/April suggest the intervention may be late. METHODS/DESIGN: This cluster-randomised controlled trial will compare two types of unconditional cash transfer for 'very poor' households in 'vulnerable' villages defined and identified by the implementing organisation. 3,500 children (6-59 months) and 2,500 women (15-49 years) will be recruited exhaustively from households targeted for cash and from a random sample of non-recipient households in 40 villages in Tahoua district. Clusters of villages with a common cash distribution point will be assigned to either a control group which will receive the standard intervention (n = 10), or a modified intervention group (n = 10). The standard intervention is 32,500 FCFA/month for 4 months, June to September, given cash-in-hand to female representatives of 'very poor' households. The modified intervention is 21,500 FCFA/month for 5 months, April, May, July, August, September, and 22,500 FCFA in June, providing the same total amount. In both arms the recipient women attend an education session, women and children are screened and referred for acute malnutrition treatment, and the households receive nutrition supplements for children 6-23 months and pregnant and lactating women. The trial will evaluate whether the modified unconditional cash transfer leads to a reduction in acute malnutrition among children 6-59 months old compared to the standard intervention. The sample size provides power to detect a 5 percentage point difference in prevalence of acute malnutrition between trial arms. Quantitative and qualitative process evaluation data will be prospectively collected and programme costs will be collected and cost-effectiveness ratios calculated. DISCUSSION: This randomised study design with a concurrent process evaluation will provide evidence on the effectiveness and cost-effectiveness of earlier initiation of seasonal unconditional cash transfer for the prevention of acute malnutrition, which will be generalisable to similar humanitarian situations. TRIAL REGISTRATION: ISRCTN25360839 , registered March 19, 2015

The economic feasibility analysis of generated photovoltaic energy in the USTO campus

The aim of this study is to analyze the economic impact of photovoltaic energy generation by a prospective campus microgrid to be installed at the University of Science and Technology (USTO). In this work, hourly solar irradiation and temperature data provided from the local weather office is used to study the distribution and duration of solar radiation over the campus. The generated solar photovoltaic energy is analyzed taking into account the economic aspects such as the photovoltaic system capital investment cost and the annual power generation cash flow. The installed power of the photovoltaic plant was calculated and the generated energy estimed. The feasility analysis shows a payback year of of 10,3, an internal rate of return of 5% and a profitability index of 1. © 2019, Wydawnictwo SIGMA-NOT. All rights reserved

The position of mefloquine as a 21st century malaria chemoprophylaxis

BACKGROUND: Malaria chemoprophylaxis prevents the occurrence of the symptoms of malaria. Travellers to high-risk Plasmodium falciparum endemic areas need an effective chemoprophylaxis. METHODS: A literature search to update the status of mefloquine as a malaria chemoprophylaxis. RESULTS: Except for clearly defined regions with multi-drug resistance, mefloquine is effective against the blood stages of all human malaria species, including the recently recognized fifth species, Plasmodium knowlesi. New data were found in the literature on the tolerarability of mefloquine and the use of this medication by groups at high risk of malaria. DISCUSSION: Use of mefloquine for pregnant women in the second and third trimester is sanctioned by the WHO and some authorities (CDC) allow the use of mefloquine even in the first trimester. Inadvertent pregnancy while using mefloquine is not considered grounds for pregnancy termination. Mefloquine chemoprophylaxis is allowed during breast-feeding. Studies show that mefloquine is a good option for other high-risk groups, such as long-term travellers, VFR travellers and families with small children. Despite a negative media perception, large pharmaco-epidemiological studies have shown that serious adverse events are rare. A recent US evaluation of serious events (hospitalization data) found no association between mefloquine prescriptions and serious adverse events across a wide range of outcomes including mental disorders and diseases of the nervous system. As part of an in-depth analysis of mefloquine tolerability, a potential trend for increased propensity for neuropsychiatric adverse events in women was identified in a number of published clinical studies. This trend is corroborated by several cohort studies that identified female sex and low body weight as risk factors. CONCLUSION: The choice of anti-malarial drug should be an evidence-based decision that considers the profile of the individual traveller and the risk of malaria. Mefloquine is an important, first-line anti-malarial drug but it is crucial for prescribers to screen medical histories and inform mefloquine users of potential adverse events. Careful prescribing and observance of contraindications are essential. For some indications, there is currently no replacement for mefloquine available or in the pipeline

Automatic structural design of RC wall-slab buildings using a genetic algorithm with application in BIM environment

International audienc

Dynamic properties of a symmetric spin nanocontact

75.30.Ds Spin waves, 75.30.Fv Spin-density waves, 75.40.Gb Dynamic properties,

Magnons coherent transmission and its heat transport at ultrathin insulating ferromagnetic nanojunctions

A model calculation is presented for the magnons coherent transmission and corresponding heat transport at magnetic insulating nanojunctions. The system consists of a ferromagnetically ordered ultrathin insulating junction between two semi-infinite ferromagnetically ordered leads. Spin dynamics are analyzed using the equations of motion for the spin precession displacements, valid for the range of temperatures of interest. Coherent scattering cross-sections at the junction boundary are calculated using the phase field matching theory, for all the incidence angles on the boundary from the lead bands, for arbitrary angles of incidence, at variable temperatures, and for different nano thicknesses of the ultrathin junction. The model is general; it is applied in particular to the Fe/Gd/Fe system with a sandwiched ferromagnetic Gd junction. It yields also the thermal conductivity due to the magnons coherent transmission between the two leads when these are maintained at slightly different temperatures. The calculation is carried out for state of the art values of the exchange constants, and elucidates the relation between the coherent scattering transmission of magnons and their thermal conductivity, for different thicknesses

Interference effects in phonon scattering across a double atomic well

We develop an analytical and numerical formalism to study the double atomic nanowell configuration influence on coherent transmission and reflection scattering, derived as elements of a Landauer-Büttiker type scattering matrix in quasi-one-dimensional multichannel waveguides. The state densities at neighbourhood of the defect region are investigated. The defect region consists in the presence of a double atomic nanowell occurring in thin film. One solves this problem by the matching method in the harmonic approximation. The theoretical formalism using simultaneously the Green's function and the matching method is detailed in order to describe the complete evanescent and the propagating fields. The phononic coherent conductance is also studied. Numerical calculations are presented and illustrated as function of the force constants occurring in the model. The fluctuations in the conductance spectra are related to Fano resonances due to the coherent coupling between travelling phonons and the localized vibration modes in the neighbourhood of the nanowell domain.