Lessons from upstream soil conservation measures to mitigate soil erosion and its impact on upstream and downstream users of the Nile River

A study was conducted to evaluate the effects of soil bunds stabilized with vetiver grass (V. zizanioides) and tree lucerne (C. palmensis) on selected soil physical and chemical properties, bund height, inter-terrace slope and barley (Hordeum vulgare L.) yield in Absela site, Banja Shikudad District, Awi administrative Zone of the Amhara National Regional State (ANRS) located in the Blue Nile Basin. The experiment had five treatments that included non-conserved land (control), a 9-year old soil bund stabilized with tree lucerne, a 9-year old soil bund stabilized with vetiver grass, a 9-year old sole soil bund, and a 6-year old soil bund stabilized with tree lucerne. Data were analyzed using one-way analysis of variance (ANOVA) and mean values for the treatments were separated using the Duncan Multiple Range Test. Results of the experiment indicated that organic carbon (OC), total nitrogen (N), bulk density, infiltration rate, bund height, and inter-terrace slope are significantly (p?0.05) affected by soil conservation measures. The non-conserved fields had significantly lower OC, total N, and infiltration rate; whereas higher bulk density as compared to the conserved fields with different conservation measures. However, no significant differences in bulk density were observed among the conservation methods. The field treated with 9-year old soil bund stabilized with tree lucerne or sole soil bund had significantly higher OC content than all other treatments. Fields having 6-year old soil bunds had lower OC and total N when compared to fields having 9-year old soil bunds irrespective of their method of stabilization. Fields with soil bunds stabilized with vetiver grass had the highest bund height and the lowest inter-terrace slope than fields with the remaining conservation measures. Barley grain and straw yields were significantly (P<0.05) greater in both the soil accumulation and loss zones of the conserved fields than the non-conserved (control) ones. In the accumulation zone, fields with the 9-year old soil bund stabilized with tree lucerne and those with the 9-year old sole soil bund gave higher grain yields (1878.5 kg ha-1 and 1712.5 kg ha-1, respectively) than fields having 9-year old soil bund stabilized with vetiver grass (1187 kg ha-1) and 6-year old soil bund stabilized with tree lucerne (1284.25 kg ha-1). When we compare the accumulation and the loss zones, the average grain yield obtained from the accumulation zones (averaged over all the Lessons from Upstream Soil Conservation Measures to Mitigate Soil Erosion and its Impact on Upstream and Downstream Users of the Nile River.Length: pp.170-183ErosionLand degradationSoil conservationBundsWater conservationSoil properties

Hydrogen content in doped and undoped BaPrO3 and BaCeO3 by cold neutron prompt-gamma activation analysis

Proton uptake in undoped and Y-doped BaPrO3 has been measured by cold neutron prompt-gamma activation analysis, and compared to the proton uptake in Gd-doped BaCeO3, as determined by the same technique. The conventional proton incorporation model of perovskites in which oxygen ion vacancies, generated by the introduction of the trivalent dopant onto the tetravalent perovskite site, are filled with hydroxyl groups upon exposure of the sample to H2O containing atmospheres, predicts that the proton concentration in such materials should be no greater than the dopant concentration. In contradiction to this model, the proton concentration in BaPr1–xYxO3 after humidification is as much as three times greater than the dopant concentration, and even undoped samples contain a high concentration of protons. Moreover, x-ray photoemission spectra suggest that the Pr oxidation state is lowered upon hydration. In contrast, BaCe0.9Y0.1O3 shows a typical hydrogen concentration, of close to 90% of the yttrium concentration. The results are interpreted in terms of the variable valence of Pr, which can become reduced from the 4+ to the 3+ oxidation state upon exposure to water, and effectively behaves as a self-dopant within the structure

Risk Factors of Deep Venous Thrombosis in Duplex and Colour Doppler Ultrasound at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia

Background: Deep venous thrombosis is a major health problem with high morbidity and mortality worldwide. Thus early, correct and definitive diagnosis is crucial in assessing thromboembolic risk and initiating therapy. In this regard Patients at risk must be identified and given appropriate prophylaxis to reduce Venous Thromboembolism related morbidity and mortality.The main objective of this study was to determine common risk factors of deep venous thrombosis (DVT) and the common sites involved by DVT in ultrasound proven cases.Methods: This was a prospective cross-sectional study which included all patients who had proven deep venous thrombosis by Dopper and duplex ultrasound at Tikur Anbessa Specialized Hospital (TASH). Senior radiology residents collected the data after getting approval from consultant radiologists. Analysis was under taken by principal investigator.Results: There were a total 81 ultrasound proven cases of DVT involving the extremities during the study period out of which 34.6% were males and 65.4% females. The majority (58%) were under the age of 40 years. Malignancy was the most common identified risk factor (30.9% of the cases) followed by prolonged immobilization 19.8%, pregnancy related problems 6.2% and severe trauma 6.2% of the patients. No apparent risk factor was found in 12.3%. Swelling was noted in 93.8% of the participants in combination with other manifestations or alone; whereas pain was noted in 70.4% of the patients. The study showed 59.3% had involvement of the left lower limb only; 11.1% had involvement of both lower limbs. The upper extremities were affected in only one patient having bilateral involvement of brachiocephalic veins. According to the study 84% of the patients had combined involvement of the deep veins of the lower extremities extending from the common iliac veins to the poplitial veins. The study revealed that 28.4% of participants were found to havecombined involvement of the common femoral vein (CFV), superficial femoral vein (SFV) &amp; poplitial vein; 22.2% had combined involvement of the CFV &amp; SFV. Conclusion: From the study we concluded that Malignancy, prolonged immobilization, pregnancy related problems and major trauma were the most common risk factors noted for DVT and Swelling was the most common presenting manifestation. Majority of the patients had multiple site deep vein involvement extending from the common iliac to the poplitial veins.Key words: Risk, Factors, Deep, Vein, Thrombosis, Duplex,Doppler

Evidence for compact cooperatively rearranging regions in a supercooled liquid

We examine structural relaxation in a supercooled glass-forming liquid simulated by NVE molecular dynamics. Time correlations of the total kinetic energy fluctuations are used as a comprehensive measure of the system's approach to the ergodic equilibrium. We find that, under cooling, the total structural relaxation becomes delayed as compared with the decay of the component of the intermediate scattering function corresponding to the main peak of the structure factor. This observation can be explained by collective movements of particles preserving many-body structural correlations within compact 3D cooperatively rearranging regions.Comment: 8 pages, 4 figure

Noncommutative polynomial maps

Accepté pour publication dans "Journal of Algebra and its applications"; 16 pages.Polynomial maps attached to polynomials of an Ore extension are naturally defi ned. In this setting we show the importance of pseudo-linear transformations and give some applications. In particular, factorizations of polynomials in an Ore extension over a fi nite fi eld F_q[t;S ], where S is the Frobenius automorphism, are translated into factorizations in the usual polynomial ring F_q[x]

Bulk Properties of the Oxygen Reduction Catalyst SrCo_(0.9)Nb_(0.1)O_(3-δ)

The perovskite SrCo_(0.9)Nb_(0.1)O_(3−δ) (SCN) has excellent electrochemical activity toward oxygen reduction, and it is also valuable as a possible model material for other state-of-the-art perovskite catalysts based on strontium and cobalt, such as Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3−δ) (BSCF). Here we report thermogravimetric, conductivity, and diffraction measurements from SCN. We find that the thermodynamic stability limits of SCN are slightly more favorable than those reported for BSCF, although both materials exhibit a slow oxidative partial decomposition under likely operating conditions. In SCN, this decomposition is thermodynamically preferred when the average formal oxidation state of cobalt is greater than ∼3.0+, but due to sluggish kinetics, metastable SCN with higher cobalt valence can be observed. The oxygen stoichiometry 3−δ varies from 2.45 to 2.70 under the conditions studied, 500–1000 °C and 10^(–4)–1 bar O_2, which encompass both stable and metastable behavior. The electronic conductivity is p-type and thermally activated, with a value at 600 °C in air of 250 S cm^(–1), comparable to that of La_(0.8)Sr_(0.2)MnO_(3−δ). The polaron migration enthalpy decreases linearly from 0.30 to 0.05 eV as 3−δ increases from 2.52 to 2.64. Thermal and chemical expansivities are also reported

Linear growth in preschool children treated with mass azithromycin distributions for trachoma: A cluster-randomized trial.

BackgroundMass azithromycin distributions have been shown to reduce mortality among pre-school children in sub-Saharan Africa. It is unclear what mediates this mortality reduction, but one possibility is that antibiotics function as growth promoters for young children.Methods and findings24 rural Ethiopian communities that had received biannual mass azithromycin distributions over the previous four years were enrolled in a parallel-group, cluster-randomized trial. Communities were randomized in a 1:1 ratio to either continuation of biannual oral azithromycin (20mg/kg for children, 1 g for adults) or to no programmatic antibiotics over the 36 months of the study period. All community members 6 months and older were eligible for the intervention. The primary outcome was ocular chlamydia; height and weight were measured as secondary outcomes on children less than 60 months of age at months 12 and 36. Study participants were not masked; anthropometrists were not informed of the treatment allocation. Anthropometric measurements were collected for 282 children aged 0-36 months at the month 12 assessment and 455 children aged 0-59 months at the month 36 assessment, including 207 children who had measurements at both time points. After adjusting for age and sex, children were slightly but not significantly taller in the biannually treated communities (84.0 cm, 95%CI 83.2-84.8, in the azithromycin-treated communities vs. 83.7 cm, 95%CI 82.9-84.5, in the untreated communities; mean difference 0.31 cm, 95%CI -0.85 to 1.47, P = 0.60). No adverse events were reported.ConclusionsPeriodic mass azithromycin distributions for trachoma did not demonstrate a strong impact on childhood growth.Trial registrationThe TANA II trial was registered on clinicaltrials.gov #NCT01202331

Agricultural resource and risk management with multiperiod stochastics: A case of the mixed crop-livestock production system in the drylands of Jordan

Generally, agricultural production involves several challenges. In the drylands, it is further complicated by weather-related risks and resource degradation. In this paper, we present a case study of the mixed crop-livestock production system in Jordan. To better capture the nature of response farming in the drylands, we develop a methodology for using crop simulation models to directly generate data for optimizing production practices of an integrated crop-livestock producing household in a dynamic stochastic context. The approach optimizes producer's adaptations to random events, such as weather, which are realized throughout the planning horizon. To ensure the sustainability of the optimized production decisions, long-term valuations of end of horizon soil attributes are included in the objective function. This approach endogenizes the tradeoff between short-and long-run productivity. Model results show that due to the limited natural resource endowments and financial liquidity constraints of the typical farm households in the study area, we find these households have limited options. To optimally respond to weather conditions during the production season, better manage risk, and achieve improvements in soil attributes, a typical household would need larger farm size, larger flock, and better financial liquidity than it currently commands. Like all such models, the farm household model used in this paper is not suitable for drawing policy implications. Therefore, targeted analysis using appropriate sectoral or economy-wide models will be needed in the future to identify and test the efficacy of different policy and institutional interventions including land consolidation, establishment of producer and marketing cooperatives, access to financial services including agricultural credit, and crop insurance in expanding the resource base of farmers-thereby positioning them for higher earnings, ensuring soil conservation, and enhancing the sustainability of the production system