IMPACTS OF PST ON OPTIMAL PRODUCTION AND MARKETING DECISIONS OF A GROW-FINISH HOG FARM OPERATION

This paper examines the impact of PST on the optimal production/marketing decisions of a grow-finish hog farm operation. The analysis evaluates PST from three angles: the feed efficiency effect, the leaner meat price effect, and the aggregate-supply-induced price effect. When limited to the feed efficiency effect only, the primary response to the new technology is to increase the animal turnover rate of the operation. When the leaner meat price effect is also included, marketing weight increases while turnover rate remains relatively unchanged. Additionally, if the increased aggregate supply depressed the market price by more than 10%, the benefits from improved feed efficiency and learner meat will be completely dissipated. Aggregate price adjustments (reductions) of less than 10 percent maintained positive producer benefits resulting from improved feed efficiency and leaner meat.Livestock Production/Industries,

The Fundamental Group on Algebraic Topology

Algebraic topology is mostly about finding invariants for topological spaces. The fundamental group is the simplest, in some ways, and the most difficult in others. This project studies the fundamental group, its basic properties, some elementary computations, and a resulting theorem. In this paper, we will examine the construction and nature of the first homotopy group, which is more commonly known as the fundamental group of a topological space. We will first briefly cover the basics of point-set topology, then use these concepts to facilitate a rigorous study of the construction of the fundamental group

Increase of Carbon Cycle Feedback with Climate Sensitivity: Results from a coupled Climate and Carbon Cycle Model

Coupled climate and carbon cycle modeling studies have shown that the feedback between global warming and the carbon cycle, in particular the terrestrial carbon cycle, could accelerate climate change and result in larger warming. In this paper, we investigate the sensitivity of this feedback for year-2100 global warming in the range of 0 K to 8 K. Differing climate sensitivities to increased CO{sub 2} content are imposed on the carbon cycle models for the same emissions. Emissions from the SRES A2 scenario are used. We use a fully-coupled climate and carbon cycle model, the INtegrated Climate and CArbon model (INCCA) the NCAR/DOE Parallel Coupled Model coupled to the IBIS terrestrial biosphere model and a modified-OCMIP ocean biogeochemistry model. In our model, for scenarios with year-2100 global warming increasing from 0 to 8 K, land uptake decreases from 47% to 29% of total CO{sub 2} emissions. Due to competing effects, ocean uptake (16%) shows almost no change at all. Atmospheric CO{sub 2} concentration increases were 48% higher in the run with 8 K global climate warming than in the case with no warming. Our results indicate that carbon cycle amplification of climate warming will be greater if there is higher climate sensitivity to increased atmospheric CO{sub 2} content; the carbon cycle feedback factor increases from 1.13 to 1.48 when global warming increases from 3.2 to 8 K

Cactus pear (Opuntia ficus-indica) productivity, proximal composition and soil parameters as affected by planting time and agronomic management in a semi-arid region of india

Study of appropriate planting time and response to agronomic management practices is imperative for the newly introduced cactus pear (Opuntia ficus-indica (L.) Mill.) into a semi-arid region of India. Responses of cactus pear to agronomic practices (planting time and irrigation and fertilizer application) were evaluated to determine the potential for fodder production and livestock feed in a semi-arid environment of India. We assessed four planting times (February, March, July and October) and two agronomic managements (with and without irrigation and fertilizer application) during 2016–2020 at Jhansi, India. Cactus pear establishment and growth improved with planting time in July and October due to favorable soil moisture and congenial temperature. However, plant height (19 cm) and cladode weight (118 g) were greater in July than in October planting. Nutrient uptake and crude protein contents, however, were higher for the earlier plantings of February and April compared to June and October. Irrigation and nutrients application had little effect on the cactus pear plant growth, except on plant width and cladode length and width. Cactus pear can be planted during July in moderately fertile soils without any agronomic intervention in semi-arid situations of India and has potential as an effective alternative source of forage for livestock during the summer months

Addressing social issues in a universal HIV test and treat intervention trial (ANRS 12249 TasP) in South Africa: methods for appraisal

Background: The Universal HIV Test and Treat (UTT) strategy represents a challenge for science, but is also a challenge for individuals and societies. Are repeated offers of provider-initiated HIV testing and immediate antiretroviral therapy (ART) socially-acceptable and can these become normalized over time? Can UTT be implemented without potentially adding to individual and community stigma, or threatening individual rights? What are the social, cultural and economic implications of UTT for households and communities? And can UTT be implemented within capacity constraints and other threats to the overall provision of HIV services? The answers to these research questions will be critical for routine implementation of UTT strategies. Methods/design: A social science research programme is nested within the ANRS 12249 Treatment-as-Prevention (TasP) cluster-randomised trial in rural South Africa. The programme aims to inform understanding of the (i) social, economic and environmental factors affecting uptake of services at each step of the continuum of HIV prevention, treatment and care and (ii) the causal impacts of the TasP intervention package on social and economic factors at the individual, household, community and health system level. We describe a multidisciplinary, multi-level, mixed-method research protocol that includes individual, household, community and clinic surveys, and combines quantitative and qualitative methods. Discussion: The UTT strategy is changing the overall approach to HIV prevention, treatment and care, and substantial social consequences may be anticipated, such as changes in social representations of HIV transmission, prevention, HIV testing and ART use, as well as changes in individual perceptions and behaviours in terms of uptake and frequency of HIV testing and ART initiation at high CD4. Triangulation of social science studies within the ANRS 12249 TasP trial will provide comprehensive insights into the acceptability and feasibility of the TasP intervention package at individual, community, patient and health system level, to complement the trial's clinical and epidemiological outcomes. It will also increase understanding of the causal impacts of UTT on social and economic outcomes, which will be critical for the long-term sustainability and routine UTT implementation. Trial registration: Clinicaltrials.gov: NCT01509508; South African Trial Register: DOH-27-0512-3974

Navigating education in the context of COVID-19 lockdowns and school closures : challenges and resilience among adolescent girls and young women in South Africa

Gender related vulnerabilities and inequalities place female learners at high risk of school disengagement due to COVID-19 disruptions. Understanding the impacts of school closures and educational disruptions on female learners in South Africa is critical to inform appropriate, gender-sensitive policies, and programs, to mitigate further exacerbation of educational inequalities. We examined the effects that COVID-19 and lockdowns have had on the educational experiences of adolescent girls and young women (AGYW) aged 15–24, in six districts of South Africa characterized by high rates of HIV, teenage pregnancy and socio-economic hardship. Following a concurrent triangulation mixed-methods approach, we conducted a cross-sectional survey with 515 AGYW, and qualitative interviews with 50 AGYW. More than half of survey participants enrolled in education had been unable to continue with their studies. Factors associated with educational disruption included low socio-economic status, lack of cell phone access and household food insecurity. Qualitative narratives included challenges with online learning and studying at home in resource restricted settings, and insufficient support from schools and teachers. However, despite multiple barriers to continuing education, some AGYW demonstrated educational resilience, enabled by psychosocial and structural support, and resource access. Our findings lend support to an emerging evidence base showing that the closure of schools and tertiary institutions, combined with challenging home environments, and a lack of access to appropriate technology, has disproportionately impacted the most vulnerable AGYW, exacerbating pre-existing educational inequalities within the South African education system. Addressing structural barriers to educational equity, particularly in the pandemic context, including access of technology and the internet, is urgent

A theoretical and empirical investigation of nutritional label use

Due in part to increasing diet-related health problems caused, among others, by obesity, nutritional labelling has been considered important, mainly because it can provide consumers with information that can be used to make informed and healthier food choices. Several studies have focused on the empirical perspective of nutritional label use. None of these studies, however, have focused on developing a theoretical economic model that would adequately describe nutritional label use based on a utility theoretic framework. We attempt to fill this void by developing a simple theoretical model of nutritional label use, incorporating the time a consumer spends reading labels as part of the food choice process. The demand equations of the model are then empirically tested. Results suggest the significant role of several variables that flow directly from the model which, to our knowledge, have not been used in any previous empirical work

Active Amplification of the Terrestrial Albedo to Mitigate Climate Change: An Exploratory Study

This study explores the potential to enhance the reflectance of solar insolation by the human settlement and grassland components of the Earth's terrestrial surface as a climate change mitigation measure. Preliminary estimates derived using a static radiative transfer model indicate that such efforts could amplify the planetary albedo enough to offset the current global annual average level of radiative forcing caused by anthropogenic greenhouse gases by as much as 30 percent or 0.76 W/m2. Terrestrial albedo amplification may thus extend, by about 25 years, the time available to advance the development and use of low-emission energy conversion technologies which ultimately remain essential to mitigate long-term climate change. However, additional study is needed to confirm the estimates reported here and to assess the economic and environmental impacts of active land-surface albedo amplification as a climate change mitigation measure.Comment: 21 pages, 3 figures. In press with Mitigation and Adaptation Strategies for Global Change, Springer, N

Adaptation and resilience : lessons learned from implementing a combination health and education intervention for adolescent girls and young women in South Africa during the COVID-19 pandemic

The COVID-19 pandemic has been associated with reduced access to health services and worsening health outcomes for HIV and sexual and reproductive health (SRH). Through the analysis of data from an evaluation study of a combination intervention for adolescent girls and young women (AGYW) in South Africa, we sought to examine the way in which implementation and service provision were impacted by the COVID-19 pandemic and related restrictions, describing the adaptation implementers made to respond to this context. The intervention was implemented from 2019 in South African districts identified as high priority, given the high rates of HIV and teenage pregnancy amongst AGYW. The South African government introduced the first COVID-19 lockdown in March 2020. We conducted in-depth interviews with 38 intervention implementers in the period from November 2020 to March 2021. Respondents described various ways in which the COVID-19 pandemic and related restrictions had limited their ability to implement the intervention and provide services as planned. As a result, AGYW intervention beneficiary access to SRH and psychosocial services was disrupted. Implementers described several ways in which they attempted to adapt to the pandemic context, such as offering services remotely or door-to-door. Despite attempts to respond to the context and adapt services, overall COVID-19 negatively affected implementation and service provision, and heightened issues around community acceptability of the programs. Our findings can help to inform efforts to reduce health service disruption, increase health system resilience, and ensure continuous SRH service provision to AGYW in times of pandemics and other crises

Claims of Potential Expansion throughout the U.S. by Invasive Python Species Are Contradicted by Ecological Niche Models

BACKGROUND: Recent reports from the United States Geological Survey (USGS) suggested that invasive Burmese pythons in the Everglades may quickly spread into many parts of the U.S. due to putative climatic suitability. Additionally, projected trends of global warming were predicted to significantly increase suitable habitat and promote range expansion by these snakes. However, the ecological limitations of the Burmese python are not known and the possible effects of global warming on the potential expansion of the species are also unclear. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that a predicted continental expansion is unlikely based on the ecology of the organism and the climate of the U.S. Our ecological niche models, which include variables representing climatic extremes as well as averages, indicate that the only suitable habitat in the U.S. for Burmese pythons presently occurs in southern Florida and in extreme southern Texas. Models based on the current distribution of the snake predict suitable habitat in essentially the only region in which the snakes are found in the U.S. Future climate models based on global warming forecasts actually indicate a significant contraction in suitable habitat for Burmese pythons in the U.S. as well as in their native range. CONCLUSIONS/SIGNIFICANCE: The Burmese python is strongly limited to the small area of suitable environmental conditions in the United States it currently inhabits due to the ecological niche preferences of the snake. The ability of the Burmese python to expand further into the U.S. is severely limited by ecological constraints. Global warming is predicted to significantly reduce the area of suitable habitat worldwide, underscoring the potential negative effects of climate change for many species