Agricultural program planning to reflect potentials of small farms with applications to Mysore State, India

India, under its Fourth Five Year Plan, is placing greater emphasis on helping small farmers to increase their productivity and incomes. Small Farmer Development Agencies (SFDA) have been established in selected districts of Mysore and other states to coordinate the activities of relevant government agencies. The concern of this disser-tation was with the program results that might potentially be achieved if the resource constraints, production capabilities, and motivations of the small farmers themselves are taken adequately into account. Possible reasons why small farmers fail to respond to assistance programs were diagnosed. A general approach was suggested for selecting representative farmers, analyzing their potential responses to such help as more credit and irrigation, and assessing the aggregate implications in terms of program benefits and resource needs. This approach,was then illustrated to the extent possible with available farm data from a distributory in the Tungabhadra Irrigation Project in Mysore State. Bearing in mind the likely limitations in time and analytical capacity of district level agencies, a three-stage approach for using information about farmer situations and potential to help determine program content was suggested: Stage 1; The application of budgeting or linear programming to representative farms to ascertain their potential output response and input needs associated with alternative assistance proposals, taking into consideration the individual resource, constraints, technical capacities, and interests that they reflect. Stage II; Aggregation of these results to estimate the areawide benefits to small farmers and costs to the Agency stemming from each program alternative. Stage III; Use of benefit-cost or linear programming analysis to obtain an optimal SFDA program mix, considering the net benefits estimated in Stage II, the resource constraints of the Agency, and its objectives. The Tungabhadra illustration drew on survey data for 40 small farms and related production input-output information that had been synthesized from several sources. In this particular application, irrigated land area and operating capital were found to be the resources that most severely constrained farmers from achieving higher incomes. The linear programming analysis also brought out the fact that it is important to have detailed information about farmers\u27 production conr-straints, such as seasonal distribution of available family and hired labor, if farmer response potentials are to be realistically estimated. When SFDA assistance in the form of production credit and/or more irri-gated land was assumed, the additional credit generally came out as contributing more to incomes than additional irrigated land, especially on the larger representative farms. Labor was not a constraint except under very liberal assumptions about additional capital and irrigated land area. The overall implication for this Tungabhadra situation at least was that if SFDA wants to maximize its net contribution to small farmer incomes, it would not necessarily provide the same mix of assistance to every farmer, nor would it rationally expect all farmers to respond with identical changes in crops or practices. This study also explored, using the Tungabhadra data to illustrate where possible, some modifications in the basic procedure that might be considered by agencies like SFDA. These included: (1) use of principal component and factor analysis to divide farms into homogeneous groups for linear programming and aggregation purposes; (2) estimation of out-put changes and input needs, given the reality that farmers do not all take advantage of new opportunities at the same pace; and (3) simple approaches that SFDA workers might consider in the near future to improve the collection and analysis of farm level information for program plan-ning purposes

Spin filtering in nanowire directional coupler

The spin transport characteristics of a nanowire directional electronic coupler have been evaluated theoretically via a transfer matrix approach. The application of a gate field in the region of mixing allows for control of spin current through the different leads of the coupler via the Rashba spin-orbit interaction. The combination of spin-orbit interaction and applied gate voltages on different legs of the coupler give rise to a controllable modulation of the spin polarization. Both structural factors and field strength tuning lead to a rich phenomenology that could be exploited in spintronic devices.Comment: 9 pages, 4 figure

Solving the time-dependent Schr\"odinger equation with absorbing boundary conditions and source terms in Mathematica 6.0

In recent decades a lot of research has been done on the numerical solution of the time-dependent Schr\"odinger equation. On the one hand, some of the proposed numerical methods do not need any kind of matrix inversion, but source terms cannot be easily implemented into this schemes; on the other, some methods involving matrix inversion can implement source terms in a natural way, but are not easy to implement into some computational software programs widely used by non-experts in programming (e.g. Mathematica). We present a simple method to solve the time-dependent Schr\"odinger equation by using a standard Crank-Nicholson method together with a Cayley's form for the finite-difference representation of evolution operator. Here, such standard numerical scheme has been simplified by inverting analytically the matrix of the evolution operator in position representation. The analytical inversion of the N x N matrix let us easily and fully implement the numerical method, with or without source terms, into Mathematica or even into any numerical computing language or computational software used for scientific computing.Comment: 15 pages, 7 figure

O Papel dos Canais do Dnos nas Várzeas do Riacho (es): Estudo de Caso Sobre a Cosntituição Técnico-científica da Configuração Territorial Capixaba

O trabalho problematiza o significado dos canais construídos pelo Departamento Nacional de Obras de Saneamento (DNOS) nas várzeas do Riacho, iniciados no decênio de 1960, entre os municípios de Aracruz e Linhares. Com base na perspectiva teórica de Milton Santos, que permite assimilar a noção de Técnica enquanto recurso epistemológico para análise e interpretação do espaço geográfico, buscou-se compreender o processo de materialização dos canais enquanto obra de engenharia, configurando-se como estudo de caso do processo de materialização da constituição técnico-científica da configuração territorial capixaba, decorrente do período modernização do Espírito Santo. O trabalho permite, ainda, compreender a inflexão sobre o uso original dos canais, concebidos inicialmente para a promoção de áreas voltadas para a produção agrícola modernizada e que, atualmente, encontram-se sob controle da Aracruz Celulose (atual Fibria), causando consideráveis impactos sobre a sociedade local

Systemic hemodynamic and regional circulatory effects of centrally administered endothelin-1 are mediated through ETA receptors

Central endothelin (ET) has been implicated in the regulation of the cardiovascular system. The effect of intracerebroventricular (i.c.v.) administration of ET-1 or IRL 1620 (5, 15 and 45 ng) on the systemic hemodynamics and regional circulation was studied in anesthetized rats using a radioactive microsphere technique. Systemic hemodynamics and regional blood circulation were determined before (baseline) and at 30 min after the injection of each dose of ET-1 or IRL 1620. Administration of saline (5 μl, i.c.v.) did not produce any significant cardiovascular effects. The lower doses of ET-1 (5 and 15 ng) did not produce any significant effect on blood pressure (BP), heart rate (HR), cardiac output (CO), stroke volume (SV), total peripheral resistance (TPR) and regional blood circulation. However, the higher dose (45 ng) produced a transient rise (26%) followed by a sustained fall (48%) in BP. The decrease in BP was accompanied by significant decreases in CO (44%) and SV (39%), while HR and TPR were not affected. ET-1 (45 ng, i.c.v.) also produced a significant reduction in blood flow to the brain (75%), heart (49%), kidneys (66%), GIT (40%), portal system (52%) and musculo-skeletal system (38%), while blood flow to the skin was not affected. To determine pharmacological specificity of the central effects of ET-1, studies were performed in rats pretreated with BQ-123, a specific ETA receptor antagonist. Pretreatment with BQ-123 (10 μg, i.c.v.), 15 min prior to the administration of ET-1, completely antagonized the systemic hemodynamic as well as the regional circulatory effects of ET-1 (45 ng, i.c.v.). In order to determine whether stimulation of central ETB receptors produces any cardiovascular effects, studies were performed using IRL 1620, a specific ETB receptor agonist. Administration of IRL 1620 (5, 15 and 45 ng, i.c.v.) did not produce any effect on systemic hemodynamics and regional blood circulation in rats. It is concluded that ETA but not ETB receptors are involved in the central cardiovascular actions of ET

What factors influence UK medical students' choice of foundation school?

Background: We aimed to identify the factors influencing UK medical student applicants’ choice of foundation school. We also explored the factors that doctors currently approaching the end of their 2-year program believe should be considered. Methods: A cross-sectional study was conducted during the 2013–2014 academic year. An online questionnaire was distributed to 2092 final-year medical students from nine UK medical schools and 84 foundation year-2 (FY2) doctors from eight foundation schools. Participants were asked to rank their top 3 from a list of 12 factors that could potentially influence choice of foundation school on a 5-point Likert scale. Collated categorical data from the two groups were compared using a chi-square test with Yates correction. Results: Geographic location was overwhelmingly the most important factor for medical students and FY2 doctors with 97.2% and 98.8% in agreement, respectively. Social relationships played a pivotal role for medical student applicants. Clinical specialties within the rotations were of less importance to medical students, in comparison to location and social relationships. In contrast, FY2 doctors placed a significantly greater importance on the specialties undertaken in their 2-year training program, when compared to medical students (chi-square; p=0.0001). Conclusion: UK medical schools should make their foundation program applicants aware of the importance of choosing rotations based on specialties that will be undertaken. Individual foundation schools could provide a more favorable linked application system and greater choice and flexibility of specialties within their 2-year program, potentially making their institution more attractive to future applicants

Tuning hole mobility in InP nanowires

Transport properties of holes in InP nanowires were calculated considering electron-phonon interaction via deformation potentials, the effect of temperature and strain fields. Using molecular dynamics, we simulate nanowire structures, LO-phonon energy renormalization and lifetime. The valence band ground state changes between light- and heavy-hole character, as the strain fields and the nanowire size are changed. Drastic changes in the mobility arise with the onset of resonance between the LO-phonons and the separation between valence subbands.Comment: 4 pages, 4 figure