9,309 research outputs found
Properties and functions of organic materials in poor agricultural soil condition
A field experiment was conducted under different soil strata in poor agricultural soil condition. Each soil stratum was treated separately with different organic material for soil fertility management. These organic materials are cow dung, sheep dung, goat dung, donkey dung, rice husks, millet husks, Acacia albida, Acacia nilotica, wood ash, house refuses, and combination of all âani-cro-berâ. In the first assessment, soil structure, texture, colour, consistency, bulk density were determined in the field, while in the second assessment N, P, K, Na, Ca, OC, OM and pH were determined under specific laboratory analysis. It is believed that the use of organic materials in soil management is a good way to improve and maintain soil quality and soil fertility rehabilitation in poor agricultural soil condition
Smallholder Supply Response and Gender in Ethiopia: A Profit Function Analysis
Empirical studies on gender and agricultural productivity are typically based on production function estimates of a single crop or aggregate output, ignoring the role of prices and endogeneity of input choice. We apply the profit function approach to farm-level data from Ethiopia to compare supply response between male and female farmers, incorporating the full range of crops and prices and non-price incentives. Gender-differential in labor productivity is accounted for by including separate variables for adult male and female labor as well as child labor. We find that women respond to price incentives as strongly as men farmers do, but responsiveness largely depends on the type of crops and the relative importance of binding constraints. In contrast to price responses, differences in the non-price effects are not qualitatively different between the two groups, with location-specific factors soliciting significantly larger share of output response than household-specific factors. The data shows that female-headed farmers are more likely to be asset-poor subsistence farmers living in climatically less favored areas; consequently, constrained by limited access to better quality land, male labor and animal traction to diversify into high-yielding fertilizer-intensive food crops. Gender-targeted interventions that explicitly address low endowment of capital by women are likely to pay-off, as well as technologies that improve the productivity of land and labor. Well-integrated pro-poor policies that facilitate access to basic physical capital and credit are equally important. Our findings suggest that broad-based price and fertilizer policies are unlikely to be optimal, as they do not target the prevailing crop and agro-climatic mixes. Broad-based infrastructure and market access policies, on the other hand, are more likely to benefit all farmers
Large Scale Earth's Bow Shock with Northern IMF as simulated by PIC code in parallel with MHD model
In this paper, we propose a 3D kinetic model (Particle-in-Cell PIC ) for the
description of the large scale Earth's bow shock. The proposed version is
stable and does not require huge or extensive computer resources. Because PIC
simulations work with scaled plasma and field parameters, we also propose to
validate our code by comparing its results with the available MHD simulations
under same scaled Solar wind ( SW ) and ( IMF ) conditions. We report new
results from the two models. In both codes the Earth's bow shock position is
found to be ~14.8 RE along the Sun-Earth line, and ~ 29 RE on the dusk side.
Those findings are consistent with past in situ observations. Both simulations
reproduce the theoretical jump conditions at the shock. However, the PIC code
density and temperature distributions are inflated and slightly shifted sunward
when compared to the MHD results. Kinetic electron motions and reflected ions
upstream may cause this sunward shift. Species distributions in the foreshock
region are depicted within the transition of the shock (measured ~2
c/{\omega}pi for {\Theta}Bn =90o and MMS =4.7 ) and in the downstream. The size
of the foot jump in the magnetic field at the shock is measured to be (1.7
c/{\omega}pi ). In the foreshocked region, the thermal velocity is found equal
to 213 km.sec-1 at 15 RE and is equal to 63 km.sec-1at 12 RE (Magnetosheath
region). Despite the large cell size of the current version of the PIC code, it
is powerful to retain macrostructure of planets magnetospheres in very short
time, thus it can be used for a pedagogical test purposes. It is also likely
complementary with MHD to deepen our understanding of the large scale
magnetosphereComment: 26 pages, 8 figures, 1 table , 66 references, JOAA-D-16-00005/201
Estimating Supply Response in the Presence of Technical Inefficiency Using the Profit Function: An Application to Ethiopian Agriculture
Studies of supply response using the profit function have typically maintained the neo- classical assumption of efficiency. Using farm-level data from Northern Ethiopia, this study examines the impact of technical inefficiency on the response of small holder farmers. Two systems of output supply and input demand functions are estimated and compared: one the standard model in which technical efficiency is assumed and another in which technical inefficiency is explicitly incorporated into the profit function. While the results from non-nested hypotheses tests are inconclusive, the model with technical inefficiency is preferred to the other model for theoretical consistency. Incorporation of inefficiency has generally increased the magnitudes and the statistical significance of own price elasticities, substantially so in the case of teff and fertilizer. The results indicate that farmers in Ethiopia do respond positively and significantly to price incentives. The results also underscore the need to improve farmerâs access to better quality land, farm inputs and credit, and public investment in roads and irrigation.Supply Response; Technical Inefficiency; Elasticities; Profit functions
Budget support, conditionality and poverty
This paper examines the effectiveness of budget support aid as an anti-poverty instrument. We argue that a major determinant of this effectiveness is the element of trust â or `social capital´, as it may be seen â which builds up between representatives of the donor and recipient. Thus we model the conditionality processes attending budget support aid, not purely in the conventional way as a non-cooperative two-person game, but rather as a non-cooperative game which may mutate into a collaborative equilibrium if sufficient trust between the negotiating parties builds up. Whether or not this happens is, we argue, fundamental to the effectiveness of conditionality, and of budget support aid. This then requires us to enquire into the determinants of trust, which - we empirically demonstrate - derive from the experience of the negotiating parties with one another, from the incentives they are able to provide to trust one another and from the processes within which their negotiations are conducted. The model is tested against two samples: extensively against a broad sample of all African countries undergoing budget support operations and intensively against a narrow sample of Ethiopia, Uganda, Malawi and Zambia. The statistical analysis suggests that trust has in practice been achieved not only through a positive `social history´ but by the transmission of forward-looking `signals´ or `bona fides´ concerning fundamentals: high pro-poor expenditure, low military expenditure, and low corruption show a positive relationship with growing trust (measured in terms of freedom from programme interruptions). Where these signals are present, budget support aid is in general growing, and slippage on overt conditionality is in general forgiven; but there are exceptions to this trend, as our case-study analysis demonstrates . A proactive stance in defence of a pro-poor strategy is positive for trust, as are certain procedural reforms including the presence of an IMF resident mission and frequent face-to-face meetings between negotiators for donor and recipient. High trust generates stability of aid, and stability of aid, in conjunction with its level and its targeting, significantly influences growth and poverty outcomes
Longitudinal performance analysis of machine learning based Android malware detectors
This paper presents a longitudinal study of the performance of machine learning classifiers for Android malware detection. The study is undertaken using features extracted from Android applications first seen between 2012 and 2016. The aim is to investigate the extent of performance decay over time for various machine learning classifiers trained with static features extracted from date-labelled benign and malware application sets. Using date-labelled apps allows for true mimicking of zero-day testing, thus providing a more realistic view of performance than the conventional methods of evaluation that do not take date of appearance into account. In this study, all the investigated machine learning classifiers showed progressive diminishing performance when tested on sets of samples from a later time period. Overall, it was found that false positive rate (misclassifying benign samples as malicious) increased more substantially compared to the fall in True Positive rate (correct classification of malicious apps) when older models were tested on newer app samples
Aid, agriculture and poverty in developing countries
We make two contributions to the debate on aid-effectiveness, illustrating that for impact on poverty what matters is not just the level but also the composition and stability of aid. One specific implication of this for aid policy is that aid most effectively reduces poverty if it supports public (and other) expenditures which are supportive of agricultural development â these, our regression analysis confirms, are not only direct expenditure on agriculture, but also education and infrastructure, and military expenditure has a negative impact. Three factors appear to be particularly conducive to the development of stable pro-poor expenditure patterms (and in particular pro-agriculture expenditure patterns). These are expenditure strategies which protect the poor against risk, the development of stable relations between governments and aid donors, and long-term political commitment to pro-poor strategies by government. The argument is pursued partly by panel-data econometric analysis of developing countries as a whole, and partly by case studies of sustained and non-sustained green revolutions in heavily aid-dependent countries in Africa
Performance evaluation of a low cost series hybrid electric vehicle
The escalating amount of vehicles on the road has raised awareness to vehicular environmental impacts and sustainability; this has provided a stimulus for future mobility considerations. The conventional car may not meet future requirements regarding noise, emissions and energy consumption. There is a distinct lack of short-term alternative solutions that meet consumer requirements and has a potential for mass production. Furthermore, the internal combustion engine has been developed over 100 years and there may be some risk that the automotive companies choose to invest into the âwrongâ alternative. This paper presents a development process in an attempt to find answer this dilemma. The first consideration is the vehicle performance criteria that take into account consumer expectations and operational/regulatory/environmental factors. Secondly, the drive train components are identified, most are commercially available, and are particular to these factors. Finally, a computer simulation isused to assess the performance of the vehicle, in comparison with the factors.The result of these investigations is a series hybrid electric vehicle that is recharged from the mains. The fuel consumption is four times better than that of a comparable car, but vehicle mass and cost have not increased significantly. The driving range of this vehicle is not limited to the battery capacity.This vehicle meets the consumer expectations as well as environmental issues and benefits with added driver comfort. Still being low-cost, it provides the potential for mass-production and thus reducing overall impacts on the environment
Mosses of Mt. Trus Madi, Sabah, Malaysia
A species list of mosses collected in Mt. Trus Madi, Sabah, between 10 September and 10 October 1996 is presented. A total of 153 taxa were collected, of which 11 are new to Borneo and five new to Sabah
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