Addition of lime and gypsum to ethiopian soils to enable lentil growth

Non-Peer Reviewe

Addition of lime and gypsum to Ethiopian soils to enable lentil growth

Non-Peer Reviewe

Food insecurity in Farta District, Northwest Ethiopia: A community based cross–sectional study

Background Access to sufficient food is essential for household welfare as well as for accomplishing other development activities. Households with insufficient access to food often face other challenges related to food insecurity including poor health and a decline in productivity. These challenges can often create a vicious circle whereby households are unable to produce enough food even during a good crop season. Thus, this study aimed to determine the magnitude of food insecurity and its determinants in rural households of Farta District, Northwest Ethiopia. Methods A community based cross-sectional study was conducted from September to October 2012. Household heads were recruited using a multistage random sampling technique. Data were collected by face-to-face interviews using the Household Food Insecurity Access Scale (HFIAS) tool after verbal informed consent. Data were entered to Epi info 2002 and exported to SPSS version 16 for analysis. Multiple logistic regressions were fitted and odds ratios with 95% confidence intervals were calculated to identify associated factors and control confounding effect. Results A total of 836 households were included in this study. Nearly three quarters of the households (70.7%) had food insecurity. Households headed by females (AOR = 3.18, 95% CI:1.08, 15.21), lack of education (AOR = 2.59, 95% CI: 1.46, 4.60), family size of 4-7 (AOR = 2.39, 95% CI: 1.21,4.70), family size of >7 (AOR = 13.23,95% CI:6.18, 28.32), few or absence of livestock (AOR = 5.60, 95% CI:1.28, 24.43), absence of income from off-farm activities (AOR = 3.12, 95% CI:1.53, 6.36), lack of irrigation (AOR = 3.54, 95% CI:2.14, 5.18) and lack of perennial income (AOR = 3.15, 95% CI:1.88, 5.27) were factors associated with food insecurity. Conclusions This study revealed that most households of the district were food insecure. Hence, the promotion of contraceptive use, off-farm employment activities and the development of small scale irrigation are important recommendations to reduce food insecurity

Low-frequency electronic noise in superlattice and random-packed thin films of colloidal quantum dots

We report measurements of low-frequency electronic noise in ordered superlattice, weakly-ordered and random-packed thin films of 6.5 nm PbSe quantum dots prepared using several different ligand chemistries. For all samples, the normalized noise spectral density of the dark current revealed a Lorentzian component, reminiscent of the generation-recombination noise, superimposed on the 1/f background (f is the frequency). An activation energy of 0.3 eV was extracted from the temperature dependence of the noise spectra. The noise level in the ordered films was lower than that in the weakly-ordered and random-packed films. A large variation in the magnitude of the noise spectral density was also observed in samples with different ligand treatments. The obtained results are important for application of colloidal quantum dot films in photodetectors.Comment: 24 pages, 6 figures and supplemental inf

Associated Viruses Threatening Sweetpotato Improvement and Production in Ethiopia

The level of virus contamination on sweetpotato germplasm resources in Ethiopia was determined. Sweetpotato ( Ipomea batatus ) accessions in fields at Awassa and Wondo Genet Research Stations had 85% typical virus symptoms with up to 100% incidence. The associated viruses were identified by Enzyme-linked immunosorbent assay (ELISA). Accordingly, out of 57 accessions serologically tested from Awassa, 22 and 21 were found to be infected by Sweetpotato feathery mottle virus (SPFMV) and Sweetpotato chlorotic stunt virus (SPCSV). Only one was infected by Sweetpotato virus 2 (SPV2). Similar serological analysis of 122 accessions from Wondo Genet revealed that SPFMV is the most frequent (64.7) followed by SPCSV (10.7%) and SPV2 in only two accessions. This is the first report of the occurrence of SPCSV and SPV2 in Ethiopia. There was a high virus contamination level of sweetpotato germplasm resources in Ethiopia.Le niveau de contamination virale sur les ressources de germoplasme de la patate douce en Ethiope a \ue9t\ue9 d\ue9termin\ue9. Les accessions de patate douce ( Ipomea batatus ) aux champs des stations de recherche d' Awassa et dans les stations de recherche de Wondo Genet a avaient (85 %) de sympt\uf4mes de virus typic avec environ 100 % d'incidence. Les virus associ\ue9s \ue9taient indentif\ue9s par l'Enzyme d'analyse immunosorbant (ELISA). En cons\ue9quence, parmi les 57 accessions d' Awassa s\ue9rologiquement test\ue9es, 22 et 21 \ue9taient trouv\ue9es infect\ue9es par la Sweetpotato feathery mottle virus (SPFMV) et Sweetpotato chlorotic stunt virus (SPCSV), alors que le sweet potato virus 2 (SPV2) n'avait affect\ue9 qu'une seule. ). Une analyse serological similaire de 122 nouvelles accessions de Wondo Genet avaient r\ue9v\ue9l\ue9 que SPFMV est le plus fr\ue9quent (64,7) suivi de SPCSV (10,7%) et SPV2 dans seulement deux accessions. Ceci est le prmier rapport sur l'occurrence de SPCSV et SPV2 en Ethiopie. Il y avait eu un niveau tr\ue8s \ue9lev\ue9 de contamination virale du germoplasme de patate douce en Ethiopie

Impact of grassland conversion to forest on groundwater recharge in the Nebraska Sand Hills

Study region: Nebraska National Forest in the High Plains Aquifer, Nebraska Sand Hills, U.S.A. Study focus: This research aimed to investigate the effects of grassland conversions to forest on recharge rates in a century-old experimental forest. The DiffeRential Evolution Adaptive Metropolis (DREAMZS) global optimization algorithm was used to calibrate the effective soil hydraulic parameters from observed soil moisture contents for 220 cm deep uniform soil profiles. The historical recharge rates were then estimated by applying the numerical model HYDRUS 1-D for simulation of two plots representing grasslands and dense pine forest conditions. New hydrological insights: The results indicate that conversion from grasslands to dense pine forests led to vegetation induced changes in soil hydraulic properties, increased rooting depth, and greater leaf area index, which together altered the water budget considerably. The impacts of land use change, expressed in percent of gross precipitation, include a 7% increase in interception associated with an increase in leaf area index, a nearly 10% increase in actual evapotranspiration, and an overall reduction of groundwater recharge by nearly 17%. Simulated average annual recharge rates decreased from 9.65 cm yr−1 in the grassland to 0.07 cm yr−1 in the pine plot. These outcomes highlight the significance of the grassland ecology for water resources, particularly groundwater recharge, in the Nebraska Sand Hills and the overall sustainability and vitality of the High Plains Aquifer

Thermal Properties of the Binary-Filler Composites with Few-Layer Graphene and Copper Nanoparticles

The thermal properties of an epoxy-based binary composites comprised of graphene and copper nanoparticles are reported. It is found that the "synergistic" filler effect, revealed as a strong enhancement of the thermal conductivity of composites with the size-dissimilar fillers, has a well-defined filler loading threshold. The thermal conductivity of composites with a moderate graphene concentration of ~15 wt% exhibits an abrupt increase as the loading of copper nanoparticles approaches ~40 wt%, followed by saturation. The effect is attributed to intercalation of spherical copper nanoparticles between the large graphene flakes, resulting in formation of the highly thermally conductive percolation network. In contrast, in composites with a high graphene concentration, ~40 wt%, the thermal conductivity increases linearly with addition of copper nanoparticles. The electrical percolation is observed at low graphene loading, less than 7 wt.%, owing to the large aspect ratio of graphene. At all concentrations of the fillers, below and above the electrical percolation threshold, the thermal transport is dominated by phonons. The obtained results shed light on the interaction between graphene fillers and copper nanoparticles in the composites and demonstrate potential of such hybrid epoxy composites for practical applications in thermal interface materials and adhesives.Comment: 25 pages, 4 figure

Low-Frequency Noise Spectroscopy of Charge-Density-Wave Phase Transitions in Vertical Quasi-2D Devices

We report results regarding the electron transport in vertical quasi-2D layered 1T-TaS2 charge-density-wave devices. The low-frequency noise spectroscopy was used as a tool to study changes in the cross-plane electrical characteristics of the quasi-2D material below room temperature. The noise spectral density revealed strong peaks - changing by more than an order-of-magnitude - at the temperatures closely matching the electrical resistance steps. Some of the noise peaks appeared below the temperature of the commensurate to nearly-commensurate charge-density-wave transition, possibly indicating the presence of the debated "hidden" phase transitions. These results confirm the potential of the noise spectroscopy for investigations of electron transport and phase transitions in novel materials.Comment: 16 pages; 5 figure

Vitamin-A deficiency and its determinants among preschool children: A community based cross-sectional study in Ethiopia

Background Vitamin A deficiency is the leading cause of preventable visual impairments in children. It is also an underlying cause for nearly one-fourth of global child mortality associated with measles, diarrhea, and malaria. The limited literature available in Ethiopia shows severe public health significance of vitamin-A deficiency. Hence the aim of the current study was to assess the prevalence and factors determining vitamin-A deficiency among preschool children in Dembia District, northwest Ethiopia. Methods A community-based cross-sectional study was conducted among preschool children of Dembia District from January to February, 2015. A multi-stage sampling, followed by a systematic sampling technique was employed to select study participants. A structured interviewer-administered questionnaire was used to collect data. Using a binary logistic regression model, multivariable analysis was fitted to identify the associated factors of vitamin-A deficiency. The adjusted odds ratio (AOR) with a 95 % confidence interval was computed to assess the strength of the association, and variables with a p value of <0.05 in multivariable analysis were considered as statistically significant. Results Six hundred eighty-one preschool children were included in the study, giving a response rate of 96.5 %. The overall prevalence of xerophthalmia was 8.6 %. The result of the multivariable analysis revealed that nonattendance at the antenatal care clinic [AOR 2.65,95 % CI (1.39,5.07)], being male [AOR 1.81, 95 % CI (1.01,3.24)], and in the age group of 49–59 months [AOR 3.00, 95 % CI (1.49,6.02)] were significantly associated with vitamin-A deficiency. Conclusions Vitamin-A deficiency is a severe public health problem in the study area. Further strengthening antenatal care utilization and giving emphasis to preschool children will help to mitigate vitamin-A deficiency in the study area