246 research outputs found

    Subsistence Entrepreneurship: The Role of Collaborative Innovation, Sustainability and Social Goals

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    There has been more interest in sustainability in an entrepreneurship setting. This has been the result of the perceived positive social benefits stemming from sustainable entrepreneurship. One of the fascinating areas of research about sustainable entrepreneurship is to understand how it has changed the nature of business. This will help provide policy insights to encourage more research into sustainable entrepreneurship. Traditionally entrepreneurship was considered purely a commercial activity, but this has changed with the advent of interest in social issues. This chapter furthers our understanding about the nature of sustainable entrepreneurship by providing an overview of emerging research trends. Important topics are discussed in a way that preempts the following chapters in the book

    Survey and management of potato pests in Uganda

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    Potato (Solanum tuberosum L.) is an important food and income generating crop for its growers. The crop is also nutritionally rich in carbohydrates, vitamins (C and B), proteins, minerals (potassium) among other nutritional components. In Uganda, potato has been recognized as a crop with potential for nutrition security and income generation. Despite these benefits, average potato yield (4.8 t/ha) in Uganda is still comparatively lower than attainable global average yield (30 to 40 t/ha), owing to several biotic and abiotic production constraints. A study was conducted to establish the status of potato pests and diseases in north eastern and south western Uganda to include districts such as Mbale, Namisindwa, Kween, Kapchorwa and Kabale, Rubanda, Kisoro, respectively. The study was aimed at assessing the incidence and prevalence of key pests and diseases affecting potato in Uganda, with special emphasis on potato cyst nematode. Several pests and diseases including leaf miner flies, aphids, potato tuber moths, whiteflies, viruses, several nematode species, bacterial wilt (Ralstonia solanacaerum), and Fusarium spp. were observed to be affecting potato. Through the prospections conducted in this survey, the potato cyst nematode (Globodera rostochiensis) was identified in north eastern and south western areas of Uganda. Male farmers were more engaged in decision-making activities for potato production than their female counterparts in Eastern Uganda. An inclusive and multi institutional team was tasked to conduct this potato disease survey; this exercise was led by the International Institute of Tropical Agriculture (IITA) and the International Fertilizer Development Centre (IFDC-GIZ), with the special cooperation of the International Potato Centre (CIP), and the active engagement of the BugiZARDI-NARO and the District Production Office of the District Local Governments and Ministry of Agriculture, Animal Industry and Fisheries-Department of National Crop Certification Services

    Influence of altitude as a proxy for temperature on key Musa pests and diseases in watershed areas of Burundi and Rwanda

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    Open Access ArticlePests and diseases are key biotic constraints limiting banana production among smallholder farmers in Eastern and Central Africa. Climate changemay favour pest and disease development and further exacerbate the vulnerability of smallholder farming systems to biotic constraints. Information on effects of climate change on pests and pathogens of banana is required by policy makers and researchers in designing control strategies and adaptation plans. Since altitude is inversely related to temperature, this study used the occurrence of key banana pests and diseases along an altitude gradient as a proxy for the potential impact of changes in temperature associated with global warming on pests and diseases. We assessed the occurrence of banana pests and diseases in 93 banana fields across three altitude ranges in Burundi and 99 fields distributed in two altitude ranges in Rwanda watersheds. Incidence and prevalence of Banana Bunchy Top Disease (BBTD) and Fusarium wilt (FW) was significantly associated with temperature and altitude in Burundi, revealing that increasing temperatures may lead to upward movement of banana diseases. No significant associations with temperature and altitude were observed for weevils, nematodes and Xanthomonas wilt of banana (BXW). Data collected in this study provides a baseline to verify and guide modelling work to predict future pest and disease distribution according to climate change scenarios. Such information is useful in informing policy makers and designing appropriate management strategies

    The Inheritance of Histone Modifications Depends upon the Location in the Chromosome in Saccharomyces cerevisiae

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    Histone modifications are important epigenetic features of chromatin that must be replicated faithfully. However, the molecular mechanisms required to duplicate and maintain histone modification patterns in chromatin remain to be determined. Here, we show that the introduction of histone modifications into newly deposited nucleosomes depends upon their location in the chromosome. In Saccharomyces cerevisiae, newly deposited nucleosomes consisting of newly synthesized histone H3-H4 tetramers are distributed throughout the entire chromosome. Methylation of lysine 4 on histone H3 (H3-K4), a hallmark of euchromatin, is introduced into these newly deposited nucleosomes, regardless of whether the neighboring preexisting nucleosomes harbor the K4 mutation in histone H3. Furthermore, if the heterochromatin-binding protein Sir3 is unavailable during DNA replication, histone H3-K4 methylation is introduced onto newly deposited nucleosomes in telomeric heterochromatin. Thus, a conservative distribution model most accurately explains the inheritance of histone modifications because the location of histones within euchromatin or heterochromatin determines which histone modifications are introduced

    HIV Testing and Treatment with the Use of a Community Health Approach in Rural Africa.

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    BACKGROUND: Universal antiretroviral therapy (ART) with annual population testing and a multidisease, patient-centered strategy could reduce new human immunodeficiency virus (HIV) infections and improve community health. METHODS: We randomly assigned 32 rural communities in Uganda and Kenya to baseline HIV and multidisease testing and national guideline-restricted ART (control group) or to baseline testing plus annual testing, eligibility for universal ART, and patient-centered care (intervention group). The primary end point was the cumulative incidence of HIV infection at 3 years. Secondary end points included viral suppression, death, tuberculosis, hypertension control, and the change in the annual incidence of HIV infection (which was evaluated in the intervention group only). RESULTS: A total of 150,395 persons were included in the analyses. Population-level viral suppression among 15,399 HIV-infected persons was 42% at baseline and was higher in the intervention group than in the control group at 3 years (79% vs. 68%; relative prevalence, 1.15; 95% confidence interval [CI], 1.11 to 1.20). The annual incidence of HIV infection in the intervention group decreased by 32% over 3 years (from 0.43 to 0.31 cases per 100 person-years; relative rate, 0.68; 95% CI, 0.56 to 0.84). However, the 3-year cumulative incidence (704 incident HIV infections) did not differ significantly between the intervention group and the control group (0.77% and 0.81%, respectively; relative risk, 0.95; 95% CI, 0.77 to 1.17). Among HIV-infected persons, the risk of death by year 3 was 3% in the intervention group and 4% in the control group (0.99 vs. 1.29 deaths per 100 person-years; relative risk, 0.77; 95% CI, 0.64 to 0.93). The risk of HIV-associated tuberculosis or death by year 3 among HIV-infected persons was 4% in the intervention group and 5% in the control group (1.19 vs. 1.50 events per 100 person-years; relative risk, 0.79; 95% CI, 0.67 to 0.94). At 3 years, 47% of adults with hypertension in the intervention group and 37% in the control group had hypertension control (relative prevalence, 1.26; 95% CI, 1.15 to 1.39). CONCLUSIONS: Universal HIV treatment did not result in a significantly lower incidence of HIV infection than standard care, probably owing to the availability of comprehensive baseline HIV testing and the rapid expansion of ART eligibility in the control group. (Funded by the National Institutes of Health and others; SEARCH ClinicalTrials.gov number, NCT01864603.)

    Thermal Testing for Cryogenic CMB Instrument Optical Design

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    Observations of the Cosmic Microwave Background rely on cryogenic instrumentation with cold detectors, readout, and optics providing the low noise performance and instrumental stability required to make more sensitive measurements. It is therefore critical to optimize all aspects of the cryogenic design to achieve the necessary performance, with low temperature components and acceptable system cooling requirements. In particular, we will focus on our use of thermal filters and cold optics, which reduce the thermal load passed along to the cryogenic stages. To test their performance, we have made a series of in situ measurements while integrating the third receiver for the BICEP Array telescope. In addition to characterizing the behavior of this receiver, these measurements continue to refine the models that are being used to inform design choices being made for future instruments.Comment: 9 pages, 8 figures, Proceedings of SPIE 202

    BICEP / Keck XVI: Characterizing Dust Polarization through Correlations with Neutral Hydrogen

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    We characterize Galactic dust filaments by correlating BICEP/Keck and Planck data with polarization templates based on neutral hydrogen (H I) observations. Dust polarization is important for both our understanding of astrophysical processes in the interstellar medium (ISM) and the search for primordial gravitational waves in the cosmic microwave background (CMB). In the diffuse ISM, H I is strongly correlated with the dust and partly organized into filaments that are aligned with the local magnetic field. We analyze the deep BICEP/Keck data at 95, 150, and 220 GHz, over the low-column-density region of sky where BICEP/Keck has set the best limits on primordial gravitational waves. We separate the H I emission into distinct velocity components and detect dust polarization correlated with the local Galactic H I but not with the H I associated with Magellanic Stream I. We present a robust, multifrequency detection of polarized dust emission correlated with the filamentary H I morphology template down to 95 GHz. For assessing its utility for foreground cleaning, we report that the H I morphology template correlates in B modes at a \sim10-65%\% level over the multipole range 20<<20020 < \ell < 200 with the BICEP/Keck maps, which contain contributions from dust, CMB, and noise components. We measure the spectral index of the filamentary dust component spectral energy distribution to be β=1.54±0.13\beta = 1.54 \pm 0.13. We find no evidence for decorrelation in this region between the filaments and the rest of the dust field or from the inclusion of dust associated with the intermediate velocity H I. Finally, we explore the morphological parameter space in the H I-based filamentary model.Comment: 27 pages, 12 figure
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