Trend analysis of extreme precipitation in the Northwestern Highlands of Ethiopia with a case study of Debre Markos

Understanding extreme precipitation is very important for Ethiopia, which is heavily dependent on low-productivity rainfed agriculture but lacks structural and non-structural water regulating and storage mechanisms. There has been an increasing concern about whether there is an increasing trend in extreme precipitation as the climate changes. Existing analysis of this region has been descriptive, without taking advantage of the advances in extreme value modeling. After reviewing the statistical methodology on extremes, this paper presents an analysis based on the generalized extreme value modeling with daily time series of precipitation records at Debre Markos in the Northwestern Highlands of Ethiopia. We found no strong evidence to reject the null hypothesis that there is no increasing trend in extreme precipitation at this location

Evaluation of bio-physiological and yield responses of stay green QTL introgression sorghum lines to post-flowering drought stress

Drought is the most drastic abiotic stress that limits crop production in sub-Sahara Africa. Sorghum ( Sorghum bicolor (L.) Moench) is among the most climate resilient cereals of the future due to its tolerance to drought and heat. Thus, identification of tolerant genotypes and plant characteristics that contribute to drought adaptation is timely. The objective of this study was to evaluate the response of 12 genotypes, including seven Stay-green (Stg) QTL introgression sorghum lines and their two donor; and three recurrent parents, to induced post-flowering drought stress. The recurrent parents were varieties released for drought prone lowlands of the country, and the donor parents were lines known to have stay-green properties. The study was conducted at Werer, in the Great Rift-valley of Ethiopia, during the off-season of 2014 under well-watered and water limited conditions. Significant differences (P<0.05) were observed among genotypes under water deficit regimes, for all measured physiological, biochemical (proline content), yield and yield related traits. Three Stg QTL introgression lines showed better tolerance to drought than their recurrent parents, as reflected by yield and maintenance of green leaf area. Three Stg QTL introgression lines, Teshale/E36-1, Gambella/B35-5 and Meko/B35-12, gave the highest grain yield under post-flowering drought stress, and B35 and Teshale/B35 gave the poorest yield under similar conditions. Therefore, these improved lines bear potential for use as alternatives in breeding programmes and for possible release in parts of the country where post-flowering drought stress is frequent. Proline content, weight of hundred seeds (HSW) and CO2 assimilation are effective screening tools for Stg property due to their high correlation with other parameters.La s\ue8cheresse est le stress abiotique le plus drastique qui limite la production agricole en Afrique Sub-saharienne. Le sorgho ( Sorghum bicolor (L.) Moench) est parmi les c\ue9r\ue9ales les plus r\ue9silientes au climat pour le futur d\ufb \ue0 sa tol\ue9rance \ue0 la s\ue9cheresse et \ue0 la chaleur. Donc, l\u2019identification des g\ue9notypes tol\ue9rants et les caract\ue9ristiques des plants qui contribuent \ue0 l\u2019adaptation \ue0 la s\ue9cheresse est opportune. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer la r\ue9ponse de 12 g\ue9notypes, comportant sept lign\ue9es de sorgho conf\ue9rant l\u2019introgression des QTL des attributs verts (Stg), leurs deux donneurs\ua0; et les trois parents r\ue9currents, au stress de la s\ue9cheresse post floraison induite. Les parents r\ue9currents ont \ue9t\ue9 les vari\ue9t\ue9s lib\ue9r\ue9es sensibles \ue0 la s\ue9cheresse dans les plaines du pays, et les donneurs ont \ue9t\ue9 les lign\ue9es connues pour leurs propri\ue9t\ue9s relatives aux attributs verts. L\u2019\ue9tude a \ue9t\ue9 conduite \ue0 Werer, dans la grande vall\ue9e du Rift d\u2019Ethiopie, pendant la contre saison de 2014 dans des conditions d\u2019irrigation abondante et d\u2019irrigation limit\ue9e. De diff\ue9rences significatives (P<0.05) ont \ue9t\ue9 observ\ue9es entre les g\ue9notypes sous des r\ue9gimes de d\ue9ficit hydriques, pour tous les traits physiologiques, biochimiques (teneur en proline), le rendement et les composantes de rendement. Trois lign\ue9es d\u2019introgression de Stg QTL ont montr\ue9 de meilleure tol\ue9rance \ue0 la s\ue9cheresse que leurs parents r\ue9currents, comme refl\ue9t\ue9 par le rendement et la maintenance de la surface verte de la feuille. Trois lign\ue9es d\u2019introgression de Stg QTL, Teshale/E36-1, Gambella/B35-5 et Meko/B35-12, ont donn\ue9 le plus haut rendement sous le stress de s\ue9cheresse de post floraison, et B35 et Teshale/B35 ont donn\ue9 le plus faible rendement dans des conditions similaires. En cons\ue9quence, ces lign\ue9es am\ue9lior\ue9es d\ue9tiennent tout le potentiel pour leur usage comme alternatives dans des programmes d\u2019am\ue9lioration g\ue9n\ue9tiques et pour une lib\ue9ration possible dans les r\ue9gions du pays o\uf9 le stress de la s\ue9cheresse post floraison est fr\ue9quent. La teneur en proline, le poids de 100 graines (HSW) et l\u2019assimilation du CO2 sont des outils effectifs de criblage pour la propri\ue9t\ue9 de Stg due \ue0 leur forte corr\ue9lation avec les autres param\ue8tres

Hydrological Foundation as a Basis for a Holistic Environmental Flow Assessment of Tropical Highland Rivers in Ethiopia

The sustainable development of water resources includes retaining some amount of the natural flow regime in water bodies to protect and maintain aquatic ecosystem health and the human livelihoods and wellbeing dependent upon them. Although assessment of environmental flows is now occurring globally, limited studies have been carried out in the Ethiopian highlands, especially studies to understand flow-ecological response relationships. This paper establishes a hydrological foundation of Gumara River from an ecological perspective. The data analysis followed three steps: first, determination of the current flow regime flow indices and ecologically relevant flow regime; second, naturalization of the current flow regime looking at how flow regime is changing; and, finally, an initial exploration of flow linkages with ecological processes. Flow data of Gumara River from 1973 to 2018 are used for the analysis. Monthly low flow occurred from December to June; the lowest being in March, with a median flow of 4.0 m(3) s(-1). Monthly high flow occurred from July to November; the highest being in August, with a median flow of 236 m(3) s(-1). 1-Day low flows decreased from 1.55 m(3) s(-1) in 1973 to 0.16 m(3) s(-1) in 2018, and 90-Day (seasonal) low flow decreased from 4.9 m(3) s(-1) in 1973 to 2.04 m(3) s(-1) in 2018. The Mann-Kendall trend test indicated that the decrease in low flow was significant for both durations at alpha = 0.05. A similar trend is indicated for both durations of high flow. The decrease in both low flows and high flows is attributed to the expansion of pump irrigation by 29 km(2) and expansion of plantations, which resulted in an increase of NDVI from 0.25 in 2000 to 0.29 in 2019. In addition, an analysis of environmental flow components revealed that only four "large floods" appeared in the last 46 years; no "large flood" occurred after 1988. Lacking "large floods" which inundate floodplain wetlands has resulted in early disconnection of floodplain wetlands from the river and the lake; which has impacts on breeding and nursery habitat shrinkage for migratory fish species in Lake Tana. On the other hand, the extreme decrease in "low flow" components has impacts on pin smaller pools. These results serve as the hydrological foundation for continued studies in the Gumara catchment, with the eventual goal of quantifying environmental flow requirements.redators, reducing their mobility and ability to access prey concentrate

If you feed them, they will come: A prospective study of the effects of complimentary food on attendance and physician attitudes at medical grand rounds at an academic medical center

<p>Abstract</p> <p>Background</p> <p>Evidence suggests that attendance at medical grand rounds at academic medical centers is waning. The present study examined whether attendance at medical grand rounds increased after providing complimentary food to attendees and also assessed attendee attitudes about complimentary food.</p> <p>Methods</p> <p>In this prospective, before-and-after study, attendance at medical grand rounds was monitored from September 25, 2002, to June 2, 2004, using head counts. With unrestricted industry (eg, pharmaceutical) financial support, complimentary food was provided to medical grand rounds attendees beginning June 4, 2003. Attendance was compared during the pre-complimentary food and complimentary food periods. Attitudes about the complimentary food were assessed with use of a survey administered to attendees at the conclusion of the study period.</p> <p>Results</p> <p>The mean (± SD) overall attendance by head counts increased 38.4% from 184.1 ± 90.4 during the pre-complimentary food period to 254.8 ± 60.5 during the complimentary food period (<it>P </it>< .001). At the end of the study period, 70.1% of the attendee survey respondents indicated that they were more likely to attend grand rounds because of complimentary food, 53.6% indicated that their attendance increased as a result of complimentary food, and 53.1% indicated that their attendance would decrease if complimentary food was no longer provided. Notably, 80.3% indicated that food was not a distraction, and 81.7% disagreed that industry representatives had influence over medical grand rounds because of their financial support for the food.</p> <p>Conclusion</p> <p>Providing free food may be an effective strategy for increasing attendance at medical grand rounds.</p

Study of growth and physiological characters in stay-green QTL introgression Sorghum bicolor (L.) lines under post-flowering drought stress

This experiment was carried out to evaluate the growth, physiological and yield traits of stay-green (Stg) QTL introgression sorghum lines, which were developed by the Ethiopian Institute of Agricultural Research in collaboration with ICRISAT between 2006 and 2008, under induced post-flowering drought stress. It involved a total of 12 genotypes including seven Stg QTL introgression lines, two Stg donor parents and three senescent recurrent parents. It was organized in a split plot design with three replications under well-watered and induced drought stress growing conditions at Melka Werer, Ethiopia during the post-rainy season of 2014. Analysis of variance revealed that the effect of moisture regimes on all measured traits was significant (P > 0.05). Differences among the genotypes and genotypeby- water regime interaction were also significant (P > 0.05) for all the traits considered. Postflowering drought stress was observed to significantly reduce most of the growth, physiological and yield related traits. The Stg introgression lines Meko/B35-selection 120, Teshale/B35-selection 2 and Teshale/E36-1 showed better drought stress tolerance properties than the rest of the genotypes based on the measured growth and physiological traits. These introgression lines also showed better grain yield than their recurrent parents under post-flowering drought stress and can be used as new versions of the existing varieties (served as recurrent parents) and for future breeding programs. Furthermore, leaf chlorophyll content, assimilation rate, transpiration rate, water use efficiency, root length and root dry weight were found to have strong correlation and can be used to screen genotypes for post-flowering drought tolerance

Integrated management of Aspergillus species and aflatoxin production in groundnut (Arachis hypogaea L.) through application of farm yard manure and seed treatments with fungicides and Trichoderma species

Groundnut (Arachis hypogaea L.) is an important cash crop in the lowland areas of Ethiopia. However, prevalence of Aspergillus invasions and subsequent aflatoxin contamination compromises the quality of groundnut kernels. This study was conducted to evaluate the effect of farm yard manure (FYM) and seed treatments against Aspergillus species pod colonization and aflatoxin accumulation under field conditions. The inhibitory efficacy of Trichoderma species as biocontrol agents was also assessed. A total of 20 treatment combinations including pre-planting applications of FYM at 0, 2.5, 5, and 7.5 tons/ha and seed treatments with carbendazim at 2 g/kg and mancozeb at 3 g kg-1, and Trichoderma harzianum and Trichoderma viride each at 5 g/kg as well as untreated seed as control were used. Treatments were laid out in a randomized complete block design (RCBD) in three replications. The experiment was conducted in two consecutive seasons (2014 and 2015) at Babile Haramaya University sub-Research Station. The highest pod and seed yields (1901.5 and 1281.5 kg/ha, respectively) were recovered from plots treated with T. harzianum at 5 g/kg seed. A. flavus was abundantly recorded in control plots, which could be responsible for the high aflatoxin B1 (5704.4 µg/kg) and B2 (2219.0 µg/kg) contamination. However, plots treated with T. harzianum at 5 g/kg seed and FYM at 5 tons/ha + T. harzianum at 5 g/kg were free from aflatoxin. Integrations of T. harzianum as biocontrol seed treatment and soil amendment with FYM were effective in the pre-harvest management of Aspergillus spp. and aflatoxins contamination

Landslide susceptibility mapping at VAZ watershed (Iran) using an artificial neural network model: a comparison between multilayer perceptron (MLP) and radial basic function (RBF) algorithms

Landslide susceptibility and hazard assessments are the most important steps in landslide risk mapping. The main objective of this study was to investigate and compare the results of two artificial neural network (ANN) algorithms, i.e., multilayer perceptron (MLP) and radial basic function (RBF) for spatial prediction of landslide susceptibility in Vaz Watershed, Iran. At first, landslide locations were identified by aerial photographs and field surveys, and a total of 136 landside locations were constructed from various sources. Then the landslide inventory map was randomly split into a training dataset 70 % (95 landslide locations) for training the ANN model and the remaining 30 % (41 landslides locations) was used for validation purpose. Nine landslide conditioning factors such as slope, slope aspect, altitude, land use, lithology, distance from rivers, distance from roads, distance from faults, and rainfall were constructed in geographical information system. In this study, both MLP and RBF algorithms were used in artificial neural network model. The results showed that MLP with Broyden–Fletcher–Goldfarb–Shanno learning algorithm is more efficient than RBF in landslide susceptibility mapping for the study area. Finally the landslide susceptibility maps were validated using the validation data (i.e., 30 % landslide location data that was not used during the model construction) using area under the curve (AUC) method. The success rate curve showed that the area under the curve for RBF and MLP was 0.9085 (90.85 %) and 0.9193 (91.93 %) accuracy, respectively. Similarly, the validation result showed that the area under the curve for MLP and RBF models were 0.881 (88.1 %) and 0.8724 (87.24 %), respectively. The results of this study showed that landslide susceptibility mapping in the Vaz Watershed of Iran using the ANN approach is viable and can be used for land use planning

Statistical tools for transgene copy number estimation based on real-time PCR

Background As compared with traditional transgene copy number detection technologies such as Southern blot analysis, real-time PCR provides a fast, inexpensive and high-throughput alternative. However, the real-time PCR based transgene copy number estimation tends to be ambiguous and subjective stemming from the lack of proper statistical analysis and data quality control to render a reliable estimation of copy number with a prediction value. Despite the recent progresses in statistical analysis of real-time PCR, few publications have integrated these advancements in real-time PCR based transgene copy number determination. Results Three experimental designs and four data quality control integrated statistical models are presented. For the first method, external calibration curves are established for the transgene based on serially-diluted templates. The Ct number from a control transgenic event and putative transgenic event are compared to derive the transgene copy number or zygosity estimation. Simple linear regression and two group T-test procedures were combined to model the data from this design. For the second experimental design, standard curves were generated for both an internal reference gene and the transgene, and the copy number of transgene was compared with that of internal reference gene. Multiple regression models and ANOVA models can be employed to analyze the data and perform quality control for this approach. In the third experimental design, transgene copy number is compared with reference gene without a standard curve, but rather, is based directly on fluorescence data. Two different multiple regression models were proposed to analyze the data based on two different approaches of amplification efficiency integration. Our results highlight the importance of proper statistical treatment and quality control integration in real-time PCR-based transgene copy number determination. Conclusion These statistical methods allow the real-time PCR-based transgene copy number estimation to be more reliable and precise with a proper statistical estimation. Proper confidence intervals are necessary for unambiguous prediction of trangene copy number. The four different statistical methods are compared for their advantages and disadvantages. Moreover, the statistical methods can also be applied for other real-time PCR-based quantification assays including transfection efficiency analysis and pathogen quantification

Epidemiology of Mycobacterium tuberculosis lineages and strain clustering within urban and peri-urban settings in Ethiopia

Background Previous work has shown differential predominance of certain Mycobacterium tuberculosis (M. tb) lineages and sub-lineages among different human populations in diverse geographic regions of Ethiopia. Nevertheless, how strain diversity is evolving under the ongoing rapid socio-economic and environmental changes is poorly understood. The present study investigated factors associated with M. tb lineage predominance and rate of strain clustering within urban and peri-urban settings in Ethiopia. Methods Pulmonary Tuberculosis (PTB) and Cervical tuberculous lymphadenitis (TBLN) patients who visited selected health facilities were recruited in the years of 2016 and 2017. A total of 258 M. tb isolates identified from 163 sputa and 95 fine-needle aspirates (FNA) were characterized by spoligotyping and compared with international M.tb spoligotyping patterns registered at the SITVIT2 databases. The molecular data were linked with clinical and demographic data of the patients for further statistical analysis. Results From a total of 258 M. tb isolates, 84 distinct spoligotype patterns that included 58 known Shared International Type (SIT) patterns and 26 new or orphan patterns were identified. The majority of strains belonged to two major M. tb lineages, L3 (35.7%) and L4 (61.6%). The observed high percentage of isolates with shared patterns (n = 200/258) suggested a substantial rate of overall clustering (77.5%). After adjusting for the effect of geographical variations, clustering rate was significantly lower among individuals co-infected with HIV and other concomitant chronic disease. Compared to L4, the adjusted odds ratio and 95% confidence interval (AOR; 95% CI) indicated that infections with L3 M. tb strains were more likely to be associated with TBLN [3.47 (1.45, 8.29)] and TB-HIV co-infection [2.84 (1.61, 5.55)]. Conclusion Despite the observed difference in strain diversity and geographical distribution of M. tb lineages, compared to earlier studies in Ethiopia, the overall rate of strain clustering suggests higher transmission and warrant more detailed investigations into the molecular epidemiology of TB and related factors

Incomplete homogenization of 18 S ribosomal DNA coding regions in Arabidopsis thaliana

<p>Abstract</p> <p>Background</p> <p>As a result of concerted evolution, coding regions of ribosomal DNA sequences are highly conserved within species and variation is generally thought to be limited to a few nucleotides. However, rDNA sequence variation has not been systematically examined in plant genomes, including that of the model plant <it>Arabidopsis thaliana </it>whose genome was the first to be sequenced.</p> <p>Findings</p> <p>Both genomic and transcribed 18 S sequences were sampled and revealed that most deviation from the consensus sequence was limited to single nucleotide substitutions except for a variant with a 270 bp deletion from position 456 to 725 in <it>Arabidopsis </it>numbering. The deletion maps to the functionally important and highly conserved 530 loop or helix18 in the structure of <it>E. coli </it>16 S. The expression of the deletion variant is tightly controlled during developmental growth stages. Transcripts were not detectable in young seedlings but could be amplified from RNA extracts of mature leaves, stems, flowers and roots of <it>Arabidopsis thaliana </it>ecotype Columbia. We also show polymorphism for the deletion variant among four <it>Arabidopsis </it>ecotypes examined.</p> <p>Conclusion</p> <p>Despite a strong purifying selection that might be expected against functionally impaired rDNAs, the newly identified variant is maintained in the <it>Arabidopsis </it>genome. The expression of the variant and the polymorphism displayed by <it>Arabidopsis </it>ecotypes suggest a transition state in concerted evolution.</p