743 research outputs found

    An Exploration of the Potential of Producing Biofuels and the Prospective Influence of Biofuels Production on Poverty Alleviation among Small-Scale Farmers in Tanzania

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    Tanzania is among the countries which depend entirely on imports for their oil needs. Consequently, the recent increases in world oil prices have led to rapid increases in the country’s expenditure on petrol and diesel imports. It is with this concern in mind that, just recently, the Tanzanian government started to think about the possibility of displacing fossil fuels with liquid biofuels. Unfortunately, however, the government has not yet backed its interest on biofuels with detailed economic analyses on the feasibility of producing biofuels in the country. Thus, the present study is an attempt to contribute towards the knowledge base regarding the feasibility of producing ethanol and biodiesel in the country. The general objective of the present study is to explore the potential of producing biofuels and the prospective influence of biofuels production on poverty alleviation among small-scale farmers in Tanzania. To achieve its objective, the present study estimates the costs of producing biofuels from various feedstocks. The estimates of the costs of producing biofuels are then compared with the prevailing petrol and diesel prices to find out whether biofuels produced in the country can compete with the traditional fossil fuels. Furthermore, the present study uses a linear programming model to determine the quantities of various crops which could be produced for use as feedstocks for producing biofuels. The results show that the costs of producing ethanol are 351, 570, 676 and 584 TZS/l for sugarcane, maize, sorghum and cassava respectively. At the same time the threshold ethanol production cost has been estimated to be 597 TZS/l. A quick comparison of the ethanol production cost figures and the threshold production cost shows that ethanol can be produced profitably in the country by using sugarcane, maize and/or cassava as feedstocks. Also the results show that ethanol can be produced competitively by using sugarcane even if world oil prices would fall to as low as US$ 40 a barrel. Moreover, the results show that the costs of producing biodiesel are 601 and 648 TZS/l for palm oil and jatropha respectively. Furthermore, the results show that the country can produce about 4010.10 and 1726.80 million litres of ethanol and biodiesel respectively. The annual demands for petrol and diesel in Tanzania are 375 and 789 million litres respectively. Thus it is clear that the country can produce enough biofuels to meet the local demand (for those fuels). The results also show that the use of sugarcane and jatropha for producing biofuels would increase the net returns for the producers of those crops by 28 and 53% respectively. In addition to increasing net returns for small-scale farmers, the results show that the production of biofuels would create about 1.8 million employment opportunities for the rural poor. Furthermore, the results show that the production of biofuels, by using sugarcane and jatropha as feedstocks, would reduce rural poverty by about 31%. Given the high potential of producing biofuels in Tanzania and their likely impact on poverty alleviation among small-scale farmers, the present study recommends deliberate efforts to attract investments in biofuels production in the country

    Factors that affect the adoption of improved maize varieties by smallholder farmers in Central Oromia, Ethiopia.

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    This study aims at identifying factors which affect the adoption of improved maize varieties in three woredas in Central Oromia, Ethiopia. The study utilized cross-sectional farm household level data collected by CIMMYT from 300 randomly selected sample households in 2012/13. Both descriptive and econometric methods have been used to analyze the data. The descriptive statistics were utilized to compare adopters and non-adopters. The logit model was employed to assess the adoption determinants.The descriptive analyses results show the existence of significant mean and proportion difference between adopters and non-adopters in terms of farmer characteristics. Adoption of the improved maize varieties among households was found to be positively influenced by adult-literacy, family size, livestock wealth, access to output market and credit access for the new varieties. On the other hand, farmer associations, distance to main markets and fertilizer credit negatively influenced adoption. Thus, the finding of this study revealed that educating farmers, strengthening extension services, improving farmer associations and improving market opportunities are some of the measures that need to be taken to enhance adoption of improved maize varieties by farmers. Keywords: improved maize varieties, small-holder farmers, adoption, determinants, Ethiopi

    Forecasting yields, prices and net returns for main cereal crops in Tanzania as probability distributions: A multivariate empirical (MVE) approach

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    Maize (Zea mays L.), sorghum (Sorghum bicolor L. Moench) and rice (Oryza sativa) are essential staple crops to the livelihoods of many Tanzanians. But the future productivity of these crops is highly uncertain due to many factors including overdependence on rain-fed, poor agricultural practices and climate change and variability. Despite the multiple risks and constraints, it is vital to highlight the pathways of cereal production in the country. Understanding the pathways of cereals helps to inform policymakers, so they can make better decisions to improve the viability of the sector and its potential to increase food production and income for the majority population. In this study, we employ a Monte Carlo simulation approach to develop a multivariate empirical (MVE) distribution model to simulate stochastic variables for main cereal crops in Tanzania. Eleven years (2008–2018) of yields and prices data for maize, sorghum and rice were used in the model to simulate and forecast yields and prices in Dodoma and Morogoro regions of Tanzania for a seven-year period, from 2019 to 2025. Dodoma and Morogoro regions represent semi-arid and sub-humid agro-ecological zones, respectively. The simulated yields and prices were used with total costs and total area harvested for each crop to calculate the probable net present value (NPV) for each agro-ecological zone. The results on crop yield show a slightly increasing trend for all three crops in Dodoma region. Likewise, rice yield is expected to marginally increase in Morogoro with a decreasing trend for maize and sorghum, meanwhile, the prices for the three crops all are projected to increase for the two regions. Generally, the results on economic feasibility in terms of NPV revealed a high probability of success for all the crops in Dodoma despite a higher relative risk for rice. The results in Morogoro presented a high probability of success for rice and sorghum with maize indicating the highest relative risk, and a 2.41% probability of negative NPV. This study helps to better understand the outlook of the main cereal crop sub-sectors in two agro-ecological zones of Tanzania over the next seven years. With high dependence on rain-fed agriculture, production of main cereals in Tanzania are likely to face a high degree of risk and uncertainty threatening livelihoods, incomes and foo

    An Economic Comparison between Alternative Rice Farming Systems in Tanzania Using a Monte Carlo Simulation Approach

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    Tanzania is the second-largest producer of rice (Oryza sativa) in Eastern, Central, and Southern Africa after Madagascar. Unfortunately, the sector has been performing poorly due to many constraints, including poor agricultural practices and climate variability. In addressing the challenge, the government is making substantial investments to speed the agriculture transformation into a more modernized, commercial, and highly productive and profitable sector. Our objective was to apply a Monte Carlo simulation approach to assess the economic feasibility of alternative rice farming systems operating in Tanzania while considering risk analysis for decision-makers with different risk preferences to make better management decisions. The rice farming systems in this study comprise rice farms using traditional practices and those using some or all of the recommended system of rice intensification (SRI) practices. The overall results show 2% and zero probability of net cash income (NCI) being negative for partial and full SRI adopters, respectively. Meanwhile, farmers using local and improved seeds have 66% and 60% probability of NCI being negative, correspondingly. Rice farms which applied fertilizers in addition to improved seeds have a 21% probability of negative returns. Additionally, net income for rice farms using local seeds was slightly worthwhile when the transaction made during the harvesting period compared to farms applied improved varieties due to a relatively high price for local seeds. These results help to inform policymakers and agencies promoting food security and eradication of poverty on the benefits of encouraging improved rice farming practices in the country. Despite climate variability, in Tanzania, it is still possible for rice farmers to increase food production and income through the application of improved technologies, particularly SRI management practices, which have shown a promising future.Peer Reviewe

    CHANG-ES XI: Circular Polarization in the Cores of Nearby Galaxies

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    We detect 5 galaxies in the CHANG-ES (Continuum Halos in Nearby Galaxies -- an EVLA Survey) sample that show circular polarization (CP) at L-band in our high resolution data sets. Two of the galaxies (NGC~4388 and NGC~4845) show strong Stokes V/ImC2V/I\,\equiv\,m_C\,\sim\,2\%, two (NGC~660 and NGC~3628) have values of mC0.3m_C\sim \,0.3\%, and NGC~3079 is a marginal detection at mC0.2m_C\sim \,0.2\%. The two strongest mCm_C galaxies also have the most luminous X-ray cores and the strongest internal absorption in X-rays. We have expanded on our previous Faraday conversion interpretation and analysis and provide analytical expressions for the expected VV signal for a general case in which the cosmic ray electron energy spectral index can take on any value. We provide examples as to how such expressions could be used to estimate magnetic field strengths and the lower energy cutoff for CR electrons. Four out of our detections are {\it resolved}, showing unique structures, including a {\it jet} in NGC~4388 and a CP `conversion disk' in NGC~4845. The conversion disk is inclined to the galactic disk but is perpendicular to a possible outflow direction. Such CP structures have never before been seen in any galaxy to our knowledge. None of the galaxy cores show linear polarization at L-band. Thus CP may provide a unique probe of physical conditions deep into radio AGNs.Comment: 30 pages, 4 figures, accepted to MNRA

    CHANG-ES IV: Radio continuum emission of 35 edge-on galaxies observed with the Karl G. Jansky Very Large Array in D-configuration, Data Release 1

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    We present the first part of the observations made for the Continuum Halos in Nearby Galaxies, an EVLA Survey (CHANG-ES) project. The aim of the CHANG-ES project is to study and characterize the nature of radio halos, their prevalence as well as their magnetic fields, and the cosmic rays illuminating these fields. This paper reports observations with the compact D configuration of the Karl G. Jansky Very Large Array (VLA) for the sample of 35 nearby edge-on galaxies of CHANG-ES. With the new wide bandwidth capabilities of the VLA, an unprecedented sensitivity was achieved for all polarization products. The beam resolution is an average of 9.6" and 36" with noise levels reaching approximately 6 and 30 microJy per beam for C- and L-bands, respectively (robust weighting). We present intensity maps in these two frequency bands (C and L), with different weightings, as well as spectral index maps, polarization maps, and new measurements of star formation rates (SFRs). The data products described herein are available to the public in the CHANG-ES data release available at www.queensu.ca/changes. We also present evidence of a trend among galaxies with larger halos having higher SFR surface density, and we show, for the first time, a radio continuum image of the median galaxy, taking advantage of the collective signal-to-noise ratio of 30 of our galaxies. This image shows clearly that a typical spiral galaxy is surrounded by a halo of magnetic fields and cosmic rays.Comment: 70 pages, of which 35 pages present the data of each galax

    Cerebrospinal fluid HIV-1 escape in patients with neurocognitive symptoms: pooled data from a neuro-HIV platform and the NAMACO study.

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    BACKGROUND Despite modern antiretroviral therapy, HIV-1 RNA escape into the cerebrospinal fluid (CSF) may occur. We examined the prevalence of and factors associated with CSF HIV-1 escape among people living with HIV (PLWH) in Switzerland. SETTING The Neurocognitive Assessment in the Metabolic and Aging Cohort (NAMACO) study is an ongoing, prospective, longitudinal, multicenter study within the Swiss HIV Cohort Study. The neuro-HIV platform is a multi-disciplinary, single-day outpatient consultation at Lausanne University Hospital. METHODS We pooled data from the NAMACO study and the neuro-HIV platform participants who underwent lumbar puncture (LP) between 2011 and 2019. Both patient groups had neurocognitive symptoms. CSF HIV-1 escape was defined as the presence of quantifiable CSF HIV-1 RNA when plasma HIV-1 RNA was suppressed or CSF HIV-1 RNA greater than plasma HIV-1 RNA when the latter was detectable. RESULTS Of 1166 PLWH assessed, 288 underwent LP. CSF HIV-1 escape was observed in 25 PLWH (8.7%) of whom 19 (76%) had supressed plasma HIV-1 RNA. Characteristics of PLWH were comparable whether they had CSF HIV-1 escape or not, including comorbidities, time since HIV diagnosis (15 vs 16 years, p=0.9), median CD4 nadir (158.5/mm3 vs 171/mm3, p=0.6), antiretroviral CSF-Penetration-Effectiveness score (7 vs 7 points, p=0.8), neurocognitive diagnosis based on Frascati criteria and radiological findings. CONCLUSIONS In this large pooled sample of PLWH with neurocognitive symptoms, CSF HIV-1 escape occurred in 8.7% of PLWH. PLWH with CSF HIV-1 escape presented no distinctive clinical or paraclinical characteristics. We conclude that LP is unavoidable in confirming CSF HIV-1 escape

    Impact of Integrase Inhibitors on Cardiovascular Disease Events in People With Human Immunodeficiency Virus Starting Antiretroviral Therapy

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    BACKGROUND Integrase strand transfer inhibitors (INSTIs) have been associated with an increased risk for cardiovascular disease (CVD) events. We investigated the impact of starting INSTI-based antiretroviral therapy (ART) on CVD events among treatment-naïve people with human immunodeficiency virus using a target trial framework, which reduces the potential for confounding and selection bias. METHODS We included Swiss HIV Cohort Study participants who were ART-naïve after May 2008, when INSTIs became available in Switzerland. Individuals were categorized according to their first ART regimen (INSTI vs other ART) and were followed from ART start until the first of CVD event (myocardial infarction, stroke, or invasive cardiovascular procedure), loss to follow-up, death, or last cohort visit. We calculated hazard ratios and risk differences using pooled logistic regression models with inverse probability of treatment and censoring weights. RESULTS Of 5362 participants (median age 38 years, 21% women, 15% of African origin), 1837 (34.3%) started INSTI-based ART, and 3525 (65.7%) started other ART. Within 4.9 years (interquartile range, 2.4-7.4), 116 CVD events occurred. Starting INSTI-based ART was not associated with an increased risk for CVD events (adjusted hazard ratio, 0.80; 95% confidence interval [CI], .46-1.39). Adjusted risk differences between individuals who started INSTIs and those who started other ART were -0.17% (95% CI, -.37 to .19) after 1 year, -0.61% (-1.54 to 0.22) after 5 years, and -0.71% (-2.16 to 0.94) after 8 years. CONCLUSIONS In this target trial emulation, we found no difference in short- or long-term risk for CVD events between treatment-naïve people with human immunodeficiency virus who started INSTI-based ART and those on other ART

    Impact of integrase inhibitors on cardiovascular disease events in people with HIV starting antiretroviral therapy.

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    BACKGROUND Integrase strand transfer inhibitors (INSTI) have been associated with an increased risk for cardiovascular disease (CVD) events. We investigated the impact of starting INSTI-based antiretroviral therapy (ART) on CVD events among treatment-naïve people with HIV (PWH) using a target trial framework, which reduces the potential for confounding and selection bias. METHODS We included Swiss HIV Cohort Study participants who were ART-naïve after 05/2008, when INSTI became available in Switzerland. Individuals were categorized according to their first ART regimen (INSTI vs. other ART) and were followed from ART start until the first of CVD event (myocardial infarction, stroke, or invasive cardiovascular procedure), loss to follow-up, death, or last cohort visit. We calculated hazard ratios and risk differences using pooled logistic regression models with inverse probability of treatment and censoring weights. RESULTS Of 5362 participants (median age 38 years, 21% women, 15% of African origin), 1837 (34.3%) started INSTI-based ART, and 3525 (65.7%) started other ART. Within 4.9 years (IQR 2.4-7.4), 116 CVD events occurred. Starting INSTI-based ART was not associated with an increase in CVD events (adjusted hazard ratio 0.80, 95% confidence interval [CI] 0.46-1.39). Adjusted risk differences between individuals who started INSTI and those who started other ART were -0.17% (95% CI -0.37-0.19) after one year, -0.61% (-1.54-0.22) after 5 years, and -0.71% (-2.16-0.94) after 8 years. CONCLUSIONS In this target trial emulation, we found no difference in short or longer term risk for CVD events between treatment-naïve PWH who started INSTI-based and those on other ART

    Anticholinergic and Sedative Medications Are Associated With Neurocognitive Performance of Well Treated People With Human Immunodeficiency Virus.

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    Background We previously showed that anticholinergic (ACH) medications contribute to self-reported neurocognitive impairment (NCI) in elderly people with human immunodeficiency virus (PWH). The current cross-sectional study further evaluated the effect of ACH and sedative drugs on neurocognitive function in PWH who underwent comprehensive neuropsychological evaluation. Methods A medication review was performed in PWH enrolled in the prospective Neurocognitive Assessment in Metabolic and Aging Cohort within the Swiss HIV Cohort Study. Neurocognitive functions were analyzed in 5 domains (motor skills, speed of information, attention/working memory, executive functions, and verbal learning memory). The effect of ACH and sedative medications on neurocognitive functioning was evaluated using linear regression models for the continuous (mean z-score) outcome and multivariable logistic regression models for the binary (presence/absence) outcome. Results A total of 963 PWH (80% male, 92% Caucasian, 96% virologically suppressed, median age 52) were included. Fourteen percent of participants were prescribed ≥1 ACH medication and 9% were prescribed ≥1 sedative medication. Overall, 40% of participants had NCI. Sedative medication use was associated with impaired attention/verbal learning and ACH medication use with motor skills deficits both in the continuous (mean z-score difference -0.26 to -0.14, P < .001 and P = .06) and binary (odds ratio [OR], ≥1.67; P < .05) models. Their combined use was associated with deficits in overall neurocognitive functions in both models (mean z-score difference -0.12, P = .002 and OR = 1.54, P = .03). These associations were unchanged in a subgroup analysis of participants without depression (n = 824). Conclusions Anticholinergic and sedative medications contribute to NCI. Clinicians need to consider these drugs when assessing NCI in PWH
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