538 research outputs found

    Dairy farming in Uganda. Production Efficiency and Soil Nutrients under Different Farming Systems

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    Prior to the 1980s, milk production in Uganda occurred largely in two contrasting production systems. In the wetter parts of the country, especially in the southwest, there were a few large, mostly government-owned commercial dairy farms on which exotic and cross-bred dairy cattle were kept in paddocks and grazed on improved or natural pastures. In the drier eastern and northeastern parts of the country, pastoralists kept large numbers of local cattle breeds, notably the Small East African Zebu (SEAZ), under traditional extensive management systems. Although the pastoralists marketed some milk, most was consumed by the household. Cattle were also valued as an expression of cultural prestige and a means of accumulating capital and meeting planned and emergency expenses. Smallholders, who tended to keep a few low yielding indigenous cattle as well as growing crops, made little contribution to the nation’s marketed milk and were primarily subsistence-oriented

    Categorisation of dairy production systems: A strategy for targeting meaningful development of the systems in Uganda

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    Dairy production is a major contributor towards national economies and household food security and incomes in sub-Saharan Africa (SSA). Milk production in the region is estimated at 1.27 million metric tonnes year-1. However, this level of milk production is inadequate for the existing human population who would require 103 million metric tonnes year-1. In Uganda, milk production only meets approximately 20% of the population's nutritional requirements. As such, methods need to be sought to increase milk production in the region. Research efforts have made strides in identifying the causes of the production-demand gap in the SSA region and a spectrum of interventions to bolster the productivity. Unfortunately, these efforts have by far yielded insignificant results. First and foremost, for exploiting the full potential of the dairy cattle population in the region, among the critical elements often overlooked in research and development processes is the recognition of systematic parametric variations within the sector, which if considered could provide entry-points for targeting intervention efforts. One such high potential entry-point is the recognition of the existence of a dairy intensification "vector" across a country or region, along which exist sections with sequentially marked nuclei of fairly uniform socio-economic and biophysical dairy sub-systems features. To enhance the process of targeting research and development in the Ugandan dairy sector, dairy production systems in the country were categorised on basis of level of intensification of production. Data were collected from 300 households in Mbarara, Masaka and Jinja districts in Uganda. The major variables derived from the data for the categorisation process were those related with milk production, expenditure, income, land area and cattle herds. The data was subjected to a cluster analysis which although produced 16 groups only five had prominent membership (above 5% of the farms). The five major clusters were selected as representative of the dairy production systems. A ranking system was used to develop an intensification continuum for the 5 systems. Herding-on own and communal land (cluster 9) was the least intensive, this was followed by Herding-mainly on own land (cluster 12) and Fenced (cluster 8) respectively. Semi-Zero Grazing (cluster 15) and Zero Grazing (cluster 13) were the most intensive dairy production systems with the latter being at the highest end of the continuum

    Too Much SALT? The Nuanced Impact of the State and Local Tax Deduction Cap on Pass-Through Business Taxpayers

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    Perhaps the most controversial provision of the Tax Cuts and Jobs Act of 2017 is the state and local tax deduction limitation (or SALT cap), partic¬ularly with respect to how the cap impacts pass-through entities in high-tax states. This particular provision of the tax law has been criticized by opponents as deliberately punitive to small businesses in blue states, while proponents maintain that eliminating the SALT cap would primar¬ily benefit high income taxpayers. Politicians from blue states have called for the repeal of the SALT cap, and some states have enacted various workarounds with questionable prospects of success. Still, many taxpay¬ers will not benefit from a SALT deduction irrespective of the SALT cap, particularly taxpayers that either take the standard deduction or are subject to the alternative minimum tax (AMT). We examine the developing law around the SALT cap and provide descriptive empirical evidence of its disparate impact on closely held business taxpayers. Consistent with prior economics literature, we find that the impact is indeed most pro¬nounced among high-income taxpayers in blue states. However, we note that the impact is substantially less than the furor over the limitation would suggest because many high-income taxpayers are subject to the AMT and so are not significantly affected by the limitation. These findings suggest two underemphasized points. First, the imposition of the SALT cap was not the drastic financial hit to blue state taxpayers that policy makers and commentators have suggested. Second, with a new adminis¬tration that favors eliminating the SALT cap, Congress could consider whether the repeal of the cap alone is enough because further changes would be needed to return the SALT deduction to its earlier prominence

    Improved Livelihoods from Grasslands; the Case of Napier Grass in Smallholder Dairy Farms in Kenya

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    In Kenya, smallholder farmers produce about 80% of the marketed milk. The farming systems vary from mixed farms with up to 10 ha of land and \u3c 10 dairy cows (Gitau et al., 1994; Anon., 1985), to intensive smallholder dairy producers in the high human population central Kenya region with 0.9 to 2 ha of land and 3-4 dairy cows (Staal et al., 2001a). Milk production depends heavily on the cultivation of forages, with Pennisetum purpureum (Napier grass) by far the most important. An estimated 350,000 of the 600,000 smallholder farms in Kenya grow and utilize P. purpureum on their farms. There are various published data indicating the level of dependence on sown forages. In a survey of 21 smallholder dairy farmers in the highlands of Kenya, Romney et al. (2004) found that P. purpureum supplied approximately 40 and 60% of the feed offered to dairy cows in the dry and wet months respectively, with the remaining feed provided by concentrates, crop residues (mainly Zea mays (maize) stover) and other cut and carry fodder such as roadside grass. In the more intensive cut and carry systems of production practiced in central Kenya, McLeod et al. (2003) found that P. purpureum was grown by over 70% of the smallholder farmers in their study area. In farm level characterisation surveys of over 3300 households conducted between 1996 and 2000 in central Kenya, 62% kept livestock and more than 50% were growing P. purpureum. Farmers were also growing fodder legumes such as Sesbania grandiflora (Sesbania), Leucaena leucocephala (Leucaena), Calliandra calothyrsus (Callindra), Desmodium intortum/uncinatum, (Desmodium) and Medicago sativa (Lucerne), but the frequency did not exceed 7.5% (Staal et al., 2001b)

    Оптимизация условий экстрагирования меланинов из лузги подсолнечника

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    Определены оптимальные значения параметров экстрагирования меланинов из лузги подсолнечника: частота вибраций 24 Гц, концентрация раствора гидроксида натрия 0,36 М, 3 ступени экстрагирования, продолжительность экстрагирования на каждой ступени 20 минут. Выход меланинов при данных условиях составил 13,09%. Полученные данные могут быть использованы при разработке технологии получения меланина из альтернативного сырья - лузги подсолнечника.Defined are the optimal values of the parameters extraction of melanin from the husks of sunflower: the vibration frequency 24 Hz, the concentration of sodium hydroxide solution 0,36 M, 3 stages of extraction, duration of extraction at each stage in 20 minutes. The degree of extraction of melanin under these conditions were 13,09%. The results obtained determine the possibility of development of technology for production melanines from alternative raw materials - sunflower husk

    Sensitive VLBI Continuum and H I Absorption Observations of NGC 7674: First Scientific Observations with the Combined Array VLBA, VLA & Arecibo

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    We present phase-referenced VLBI observations of the radio continuum emission from, and the H I 21 cm absorption toward, the Luminous Infrared Galaxy NGC 7674. The observations were carried out at 1380 MHz using the VLBA, the phased VLA, and theArecibo radio telescope. These observations constitute the first scientific use of the Arecibo telescope in a VLBI observation with the VLBA. The high- and low-resolution radio continuum images reveal several new continuum structures in the nuclear region of this galaxy. At ~100 mas resolution, we distinguish six continuum structures extending over 1.4 arcsec, with a total flux density of 138 mJy. Only three of these structures were known previously. All these structures seem to be related to AGN activity. At the full resolution of the array, we only detect two of the six continuum structures. Both are composed of several compact components with brightness temperatures on the order of 10710^{7} K. While it is possible that one of these compact structures could host an AGN, they could also be shock-like features formed by the interaction of the jet with compact interstellar clouds in the nuclear region of this galaxy. Complex H I absorption is detected with our VLBI array at both high and low angular resolution. Assuming that the widest H I feature is associated with a rotating H I disk or torus feeding a central AGN, we estimate an enclosed dynamical mass of ~7 x 10^7 M_sun, comparable to the value derived from the hidden broad Hβ\beta emission in this galaxy. The narrower H I lines could represent clumpy neutral hydrogen structures in the H I torus. The detection of H I absorption toward some of the continuum components, and its absence toward others, suggest an inclined H I disk or torus in the central region of NGC 7674.Comment: 37 pages, 11 figures. ApJ accepted. To appear in the Nov. 10, 2003 issue of ApJ. Please use the PDF version if the postscript doesn't show the figure

    DiFX2: A more flexible, efficient, robust and powerful software correlator

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    Software correlation, where a correlation algorithm written in a high-level language such as C++ is run on commodity computer hardware, has become increasingly attractive for small to medium sized and/or bandwidth constrained radio interferometers. In particular, many long baseline arrays (which typically have fewer than 20 elements and are restricted in observing bandwidth by costly recording hardware and media) have utilized software correlators for rapid, cost-effective correlator upgrades to allow compatibility with new, wider bandwidth recording systems and improve correlator flexibility. The DiFX correlator, made publicly available in 2007, has been a popular choice in such upgrades and is now used for production correlation by a number of observatories and research groups worldwide. Here we describe the evolution in the capabilities of the DiFX correlator over the past three years, including a number of new capabilities, substantial performance improvements, and a large amount of supporting infrastructure to ease use of the code. New capabilities include the ability to correlate a large number of phase centers in a single correlation pass, the extraction of phase calibration tones, correlation of disparate but overlapping sub-bands, the production of rapidly sampled filterbank and kurtosis data at minimal cost, and many more. The latest version of the code is at least 15% faster than the original, and in certain situations many times this value. Finally, we also present detailed test results validating the correctness of the new code.Comment: 28 pages, 9 figures, accepted for publication in PAS

    Rapid pathogen-specific phenotypic antibiotic susceptibility testing using digital LAMP quantification in clinical samples

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    Rapid antimicrobial susceptibility testing (AST) is urgently needed for informing treatment decisions and preventing the spread of antimicrobial resistance resulting from the misuse and overuse of antibiotics. To date, no phenotypic AST exists that can be performed within a single patient visit (30 min) directly from clinical samples. We show that AST results can be obtained by using digital nucleic acid quantification to measure the phenotypic response of Escherichia coli present within clinical urine samples exposed to an antibiotic for 15 min. We performed this rapid AST using our ultrafast (~7 min) digital real-time loop-mediated isothermal amplification (dLAMP) assay [area under the curve (AUC), 0.96] and compared the results to a commercial (~2 hours) digital polymerase chain reaction assay (AUC, 0.98). The rapid dLAMP assay can be used with SlipChip microfluidic devices to determine the phenotypic antibiotic susceptibility of E. coli directly from clinical urine samples in less than 30 min. With further development for additional pathogens, antibiotics, and sample types, rapid digital AST (dAST) could enable rapid clinical decision-making, improve management of infectious diseases, and facilitate antimicrobial stewardship

    VLBA Continuum and H I Absorption Observations of the Ultra-Luminous Infrared Galaxy IRAS 17208-0014

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    We present phase-referenced VLBI observations of the radio continuum emission from, and the neutral hydrogen 21 cm absorption toward, the Ultra-Luminous Infrared Galaxy IRAS 17208-0014. The observations were carried out at 1362 MHz using the Very Long Baseline Array, including the phased Very Large Array as an element. The high-resolution radio continuum images reveal a nuclear starburst region in this galaxy, which is composed of diffuse emission approximately 670 x 340 pc on the plane of the sky, and a number of compact sources. These sources are most likely to be clustered supernova remnants and/or luminous radio supernovae. Their brightness temperatures range over (2.2-6.6) x 10^{5} K, with radio spectral luminosities between (1-10) x 10^{21} W Hz^{-1}. The total VLBI flux density of the starburst region is ~52 mJy, which is about 50% of the total flux density detected with the VLA at arcsecond resolution. For this galaxy, we derive a massive star formation rate of ~84pm13 M{_\odot} yr^{-1}, and a supernova rate of ~4pm1 yr^{-1}. H I absorption is detected in multiple components with optical depths ranging between 0.3 and 2.5, and velocity widths between 58 and 232 km s^{-1}. The derived column densities, assuming T_{s}=100 K, range over (10-26) x 10^{21} cm^{-2}. The H I absorption shows a strong velocity gradient of 453 km s^{-1} across 0.36 arcsec (274 pc). Assuming Keplerian motion, the enclosed dynamical mass is about 2.3 x 10^9 sin^{-2}i M{_\odot}, comparable to the enclosed dynamical mass estimated from CO observations.Comment: 26 pages total, 6 figures. ApJ accepted. To appear in the April 1, 2003 issue of ApJ. For a version with better images, see http://www.aoc.nrao.edu/~emomjian/IRAS.p
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