853 research outputs found

    A cross-sectional study on bovine trypanosomosis in Jawi district of Amhara Region, Northwest Ethiopia

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    A cross-sectional study was carried out from December 2008 to March 2009 in Jawi district of Amhara Regional State northwest Ethiopia to assess the prevalence of bovine trypanosomosis. Blood sample was collected randomly from a total of 300 cattle through piercing of the marginal ear vein to determine the prevalence and measure PCV values for the assessment of anemia. During sampling age, sex and body condition of the animals were recorded to infer risk factors for the occurrence of the disease. The buffy coat technique was em ployed for the detection of trypanosome and to measure PCV values. Thin blood smear was made from positive samples for species identification of the parasite. The prevalence of trypanosomosis was found to be 11.33% (95% CI: 0.08 - 0.15%) in Jawi district of which higher prevalence with species of trypanosome was detected to be for T. congolense (65%) than T. vivax (35%). The prevalence showed no significant difference in susceptibility between sex categories and in age groups. The infection rate between body condition score in parasitaemic and aparasitaemic animals was significantly different (P< 0.05) that poor body conditioned animals were more affected by trypanosomes than good conditioned animals. The mean PCV values in parasitaemic animals was 24.29% +5.58SD while in aparasitaemic animals 27.46% +5.67SD with a statistical significant difference (

    A monitoring and evaluation framework to assess the performance of innovation platforms in the context of livestock value chains

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    Growing local and informal markets in Asia and Africa provide both challenges and opportunities for small holders. In developing countries, market failures often lead to suboptimal performance of the value chains and limited and inequitable participation of the poor. In recent years, innovation platforms have been promoted as mechanisms to stimulate and support multistakeholder collaboration in the context of research for development. They are recognized as having the potential to link value chain actors, and enhance communication and collaboration to overcome market failures. Despite the increased use of innovation platforms in research for development projects and programs, a monitoring and evaluation framework that encompasses the dynamic nature of innovation systems and value chains is not available. In this paper, the authors aim to develop a monitoring and evaluation framework for understanding and assessing the performance of innovation platforms in the context of pro-poor value chains, based on a discussion of various approaches

    Population structure of Gibberella xylarioides Heim and Saccas in Ethiopian forest coffee (Coffea arabica L.) systems

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    Coffee wilt caused by Gibberella xylarioides (Fusarium xylarioides) is a troublesome soil borne disease of Arabica coffee (Coffea arabica L.) in Ethiopia. It has been known to be prevalent and severe in plantation, garden and semi-forest coffee production systems in that order of importance. A number of recent reports have also indicated that the disease is equally damaging coffee trees with varying intensities thereby endangering the conservation of wild coffee genetic resources in forest coffee systems of the country. However, the reasons for the disease upsurge in the forest remain speculative. Thus, population structure of coffee wilt pathogen was studied by cross inoculating 12 accessions with four isolates collected in the four forest sites, namely, Bonga, Berhane-Kontir and Yayu (southwest) and Harenna (southeast) of Ethiopia. A pathogenic isolate ‘Gx11’ and a moderately resistant coffee cultivar cv. 7440, both from plantation were included as respective standard checks. The cultural and morphological characteristics of 24 isolates from the forests were compared with six strains collected from semi-forest and plantation coffee. The cultural appearance of most isolates from southwest was generally similar in pigments, aerial and radial growths but relatively different from those isolates collected in the Southeast forest site (Harenna). The result of coffee accession by isolate interactions showed that accessions of Harenna (P4, P6 and P11) were resistant to almost all isolates (except to its isolate) with low mean percent seedling deaths (&lt; 31%) while Bonga (P27) and Berhane-Kontir accessions (P34 and P38) were highly susceptible to all isolates with higher seedling deaths of 79.2 to 85.7%. The Harenna isolate was most aggressive (78.7%) followed by Bonga ‘B23’ and Yayu ‘Y21’ isolates which were as aggressive as the one from plantation coffee ‘G11’. In conclusion, the fungus population structure in the forest coffee sites have basically similar cultural and morphological characteristics of the species G. xylarioides (F. xylarioides) with certain differences between southwest and southeast in colony growth nature, pigmentation and aggressiveness. The study evidenced that the pathogen strains in the forest coffee are equally or even more aggressive than those strains in other coffee production systems, thus rapidly threatening Arabica coffee gene pool of Ethiopia.Keywords: Aggressiveness, colony growth, forest coffee, Fusarium xylarioides, coffee production systems, host-pathogen interactionsAfrican Journal of Biotechnology Vol. 12(33), pp. 5157-516

    On Exact Superpotentials, Free Energies and Matrix Models

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    We discuss exact results for the full nonperturbative effective superpotentials of four dimensional N=1\mathcal{N}=1 supersymmetric U(N) gauge theories with additional chiral superfield in the adjoint representation and the free energies of the related zero dimensional bosonic matrix models with polynomial potentials in the planar limit using the Dijkgraaf-Vafa matrix model prescription and integrating in and out. The exact effective superpotentials are produced including the leading Veneziano-Yankielowicz term directly from the matrix models. We also discuss how to use integrating in and out as a tool to do random matrix integrals in the large NN limit.Comment: 14 pages; v2: typos corrected; v3: the scheme for computing exact superpotentials including both the Veneziano-Yankielowicz term and all instanton corrections directly using matrix models is emphasized and references added, to appear in JHE

    An unidentified TeV source in the vicinity of Cygnus OB2

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    Deep observation (∼113 hrs) of the Cygnus region at TeV energies using the HEGRA stereoscopic system of air Čerenkov telescopes has serendipitously revealed a signal positionally inside the core of the OB association Cygnus OB2, at the edge of the 95% error circle of the EGRET source 3EG J2033+4118, and ∼0.5° north of Cyg X-3. The source centre of gravity is RA αJ2000: 20hr32m07s± 9.2stats±2.2syss, Dec δJ2000: +41°30′30″2.0stat±0.4′sys. The source is steady, has a post-trial significance of +4.6σ, indication for extension with radius 5.6′ at the ∼3σ level, and has a differential power-law flux with hard photon index of - 1.9 ± 0.3stat ± 0.3sys. The integral flux above 1 TeV amounts ∼3% that of the Crab. No counterpart for the TeV source at other wavelengths is presently identified, and its extension would disfavour an exclusive pulsar or AGN origin. If associated with Cygnus OB2, this dense concentration of young, massive stars provides an environment conducive to multi-TeV particle acceleration and likely subsequent interaction with a nearby gas cloud. Alternatively, one could envisage γ-ray production via a jet-driven termination shock.F. A. Aharonian, ... G. P. Rowell, ... [et al

    Scale-up of ART in Malawi has reduced case notification rates in HIV-positive and HIV-negative tuberculosis.

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    Setting: For 30 years, Malawi has experienced a dual epidemic of human immunodeficiency virus (HIV) infection and tuberculosis (TB) that has recently begun to be attenuated by the scale-up of antiretroviral therapy (ART). Objective: To report on the correlation between ART scale-up and annual national TB case notification rates (CNR) in Malawi, stratified by HIV-positive and HIV-negative status, from 2005 to 2015. Design: A retrospective descriptive ecological study using aggregate data from national reports. Results: From 2005 to 2015, ART was scaled up in Malawi from 28 470 to 618 488 total patients, with population coverage increasing from 2.4% to 52.2%. During this time, annual TB notifications declined by 35%, from 26 344 to 17 104, and the TB CNR per 100 000 population declined by 49%, from 206 to 105. HIV testing uptake increased from 51% to 92%. In known HIV-positive TB patients, the CNR decreased from a high of 1247/100 000 to 710/100 000, a 43% decrease. In known HIV-negative TB patients, the CNR also decreased, from a high of 66/100 000 to 49/100 000, a 26% decrease. Conclusion: TB case notifications have continued to decline in association with ART scale-up, with the decline seen more in HIV-positive than HIV-negative TB. These findings have programmatic implications for national TB control efforts

    N=1 Supersymmetric SU(2)rSU(2)^r Moose Theories

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    We study the quantum moduli spaces and dynamical superpotentials of four dimensional SU(2)rSU(2)^r linear and ring moose theories with N=1\mathcal{N}=1 supersymmetry and link chiral superfields in the fundamental representation. Nontrivial quantum moduli spaces and dynamical superpotentials are produced. When the moduli space is perturbed by generic tree level superpotentials, the vacuum space becomes discrete. The ring moose is in the Coulomb phase and we find two singular submanifolds with a nontrivial modulus that is a function of all the independent gauge invariants needed to parameterize the quantum moduli space. The massive theory near these singularities confines. The Seiberg-Witten elliptic curve that describes the quantum moduli space of the ring moose is produced.Comment: 26 pages, 4 figures. A few comments and references added. To appear in PR

    Bioimpedance index for measurement of total body water in severely malnourished children: Assessing the effect of nutritional oedema

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    Restoration of body composition indicates successful management of severe acute malnutrition (SAM). Bioimpedance (BI) index (height(2)/resistance) is used to predict total body water (TBW) but its performance in SAM, especially with oedema, requires further investigation

    Structures in the Gauge/Gravity Duality Cascade

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    We study corrections to the anomalous mass dimension and their effects in the Seiberg duality cascade in the Klebanov-Strassler throat, where N=1\mathcal{N}=1 supersymmetric SU(N+M)×SU(N)SU(N+M)\times SU(N) gauge theory with bifundamental chiral superfields and a quartic tree level superpotential in four dimensions is dual to type IIB string theory on AdS5×T1,1AdS_5 \times T^{1,1} background. Analyzing the renormalization group flow of the couplings on the gauge theory side, we propose specific corrections to the anomalous mass dimension. Applying gauge/gravity duality, we then show that the corrections reveal structures on the supergravity side with steps appearing in the running of the fluxes and the metric. The "charges" at the steps provide a gravitational source for Seiberg duality transformations. The finiteness of these corrections suggests that the theory flows to a baryonic branch rather than to a confining branch. The cosmological implication of the duality cascade and the gauge/gravity duality on the brane inflationary scenario and the cosmic microwave background radiation is pointed out.Comment: v3: 40 pages, minor changes and typos fixe

    Validation of bioelectrical impedance analysis in Ethiopian adults with HIV

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    Bioelectrical impedance analysis (BIA) is an inexpensive, quick and non-invasive method to determine body composition. Equations used in BIA are typically derived in healthy individuals of European descent. BIA is specific to health status and ethnicity and may therefore provide inaccurate results in populations of different ethnic origin and health status. The aim of the present study was to test the validity of BIA in Ethiopian antiretroviral-naive HIV patients. BIA was validated against the 2H dilution technique by comparing fat-free mass (FFM) measured by the two methods using paired t tests and Bland-Altman plots. BIA was based on single frequency (50 kHz) whole-body measurements. Data were obtained at three health facilities in Jimma Zone, Oromia Region, South-West Ethiopia. Data from 281 HIV-infected participants were available. Two-thirds were female and the mean age was 32·7 (sd 8·6) years. Also, 46 % were underweight with a BMI below 18·5 kg/m2. There were no differences in FFM between the methods. Overall, BIA slightly underestimated FFM by 0·1 kg (-0·1, 95 % CI -0·3, 0·2 kg). The Bland-Altman plot indicated acceptable agreement with an upper limit of agreement of 4·5 kg and a lower limit of agreement of -4·6 kg, but with a small correlation between the mean difference and the average FFM. BIA slightly overestimated FFM at low values compared with the 2H dilution technique, while it slightly underestimated FFM at high values. In conclusion, BIA proved to be valid in this population and may therefore be useful for measuring body composition in routine practice in HIV-infected African individuals
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