811 research outputs found
Livelihoods, Land and Political Economy: Reflections on Sam Moyo’s Research Methodology
This article focuses on the methodological lessons from Sam Moyo’s scholarship. Sam’s research is characterised by a combination of detailed empirical investigation, deep knowledge of the technical and practical aspects of agricultural production and farming livelihoods, and bigpicture political economy analysis and theory. Sam’s method is an insightful contemporary application of the method originally set out in Marx’s Grundrisse. Many contemporary explorations of agrarian political economy fail to sustain the important tension and dialectical debate, between diverse empirical realities and their ‘multiple determinations and relations’ and wider theorisation of the ‘concrete’ features of emergent processes of change. The implications of Sam’s methodological approach for the analysis of Zimbabwe’s land reform are discussed, especially in relation to the land occupations and the politics of agrarian reform since 2000
Economic impacts of cassava research and extension in Malawi and Zambia
This paper estimates the economic impacts of cassava research and extension in Malawi and Zambia over the period 1990-2008. The data come from sample household surveys, planting material production records, and a series of cassava improvement experiments conducted in the two countries. Past investments in cassava improvement have led to the development and release of a good number of high-yielding and cassava mosaic virus disease (CMD)-tolerant cassava varieties. The results show relatively higher adoption rates for the CMD-free local varieties compared to CMD-tolerant varieties that have been released in the two countries. The adoption of new varieties has been low and slow largely due to the fact that most of these varieties lacked the consumption attributes highly valued by farmers. The multiplication and distribution of CMD-free planting materials of the recommended local varieties led to greater adoption, but infection with CMD three to four years after adoption meant that the yield gains and economic benefits could not be sustained. Nevertheless, the multiplication and distribution of clean cassava planting materials generated a modest rate of return of 24%, which is actually consistent with an earlier rate of return estimate of 9 to 22% for cassava improvement in developing countries. Analysis of the ex ante impacts of current and future investments in cassava improvement shows that cassava improvement research that focuses on the development and dissemination of varieties with highly preferred consumption and industrial attributes would yield a greater rate of return of 40%
Two dimensional dynamical systems which admit Lie and Noether symmetries
We prove two theorems which relate the Lie point symmetries and the Noether
symmetries of a dynamical system moving in a Riemannian space with the special
projective group and the homothetic group of the space respectively. The
theorems are applied to classify the two dimensional Newtonian dynamical
systems, which admit a Lie point/Noether symmetry. Two cases are considered,
the non-conservative and the conservative forces. The use of the results is
demonstrated for the Kepler - Ermakov system, which in general is
non-conservative and for potentials similar to the H\`enon Heiles potential.
Finally it is shown that in a FRW background with no matter present, the only
scalar cosmological model which is integrable is the one for which 3-space is
flat and the potential function of the scalar field is exponential. It is
important to note that in all applications the generators of the symmetry
vectors are found by reading the appropriate entry in the relevant tables.Comment: 25 pages, 17 table
Zimbabwe’s land reform: challenging the myths
Most commentary on Zimbabwe’s land reform insists that agricultural production has almost totally collapsed, that food insecurity is rife, that rural economies are in precipitous decline, that political ‘cronies’ have taken over the land and that farm labour has all been displaced. This paper however argues that the story is not simply one of collapse and catastrophe; it is much more nuanced and complex, with successes as well as failures. The paper provides a summary of some of the key findings from a ten-year study in Masvingo province and the book Zimbabwe’s Land Reform: Myths and Realities. The paper documents the nature of the radical transformation of agrarian structure that has occurred both nationally and within the province, and the implications for agricultural production and livelihoods. A discussion of who got the land shows the diversity of new settlers, many of whom have invested substantially in their new farms. An emergent group ‘middle farmers’ is identified who are producing, investing and accumulating. This has important implications – both economically and politically – for the future, as the final section on policy challenges discusses.ESR
Схемотехническое моделирование и синтез активных СВЧ-фильтров на полевых транзисторах Шоттки
Разработаны схемы активных СВЧ-фильтров, пригодных для исполнения в виде гибридной или полупроводниковой микросхемы
Midwifery 2030: A woman's pathway to health. What does this mean?
© 2015 The Authors. The 2014 State of the World's Midwifery report included a new framework for the provision of woman-centred sexual, reproductive, maternal, newborn and adolescent health care, known as the Midwifery2030 Pathway. The Pathway was designed to apply in all settings (high-, middle- and low-income countries, and in any type of health system). In this paper, we describe the process of developing the Midwifery2030 Pathway and explain the meaning of its different components, with a view to assisting countries with its implementation.The Pathway was developed by a process of consultation with an international group of midwifery experts. It considers four stages of a woman's reproductive life: (1) pre-pregnancy, (2) pregnancy, (3) labour and birth, and (4) postnatal, and describes the care that women and adolescents need at each stage. Underpinning these four stages are ten foundations, which describe the systems, services, workforce and information that need to be in place in order to turn the Pathway from a vision into a reality. These foundations include: the policy and working environment in which the midwifery workforce operates, the effective coverage of sexual, reproductive, maternal, newborn and adolescent services (i.e. going beyond availability and ensuring accessibility, acceptability and high quality), financing mechanisms, collaboration between different sectors and different levels of the health system, a focus on primary care nested within a functional referral system when needed, pre- and in-service education for the workforce, effective regulation of midwifery and strengthened leadership from professional associations. Strengthening of all of these foundations will enable countries to turn the Pathway from a vision into reality
Evaluating the cost-effectiveness of TB diagnostic strategies in HIV-positive patients in Lusaka, Zambia
Neuroimaging measurements derived from magnetic resonance imaging provide important information required for detecting changes related to the progression of mild cognitive impairment (MCI). Cortical features and changes play a crucial role in revealing unique anatomical patterns of brain regions, and further differentiate MCI patients from normal states. Four cortical features, namely, gray matter volume, cortical thickness, surface area, and mean curvature, were explored for discriminative analysis among three groups including the stableMCI (sMCI), the convertedMCI (cMCI), and the normal control (NC) groups. In this study, 158 subjects (72 NC, 46 sMCI, and 40 cMCI) were selected from the Alzheimer's Disease Neuroimaging Initiative. A sparse-constrained regression model based on the l2-1-norm was introduced to reduce the feature dimensionality and retrieve essential features for the discrimination of the three groups by using a support vector machine (SVM). An optimized strategy of feature addition based on the weight of each feature was adopted for the SVM classifier in order to achieve the best classification performance. The baseline cortical features combined with the longitudinal measurements for 2 years of follow-up data yielded prominent classification results. In particular, the cortical thickness produced a classification with 98.84% accuracy, 97.5% sensitivity, and 100% specificity for the sMCI-cMCI comparison; 92.37% accuracy, 84.78% sensitivity, and 97.22% specificity for the cMCI-NC comparison; and 93.75% accuracy, 92.5% sensitivity, and 94.44% specificity for the sMCI-NC comparison. The best performances obtained by the SVM classifier using the essential features were 5-40% more than those using all of the retained features. The feasibility of the cortical features for the recognition of anatomical patterns was certified; thus, the proposed method has the potential to improve the clinical diagnosis of sub-types of MCI and predict the risk of its conversion to Alzheimer's diseas
Уровень провоспалительных цитокинов внутриматочных смывов при гиперплазиях эндометрия
Проведено вивчення змін рівня прозапальних цитокінів ІЛ -1ß, ІЛ -6 та ФНП-α в маткових змивах у
жінок з різними видами гіперплазій ендометрію. Встановлено, що формування гіперплазії ендометрію
супроводжується активацією прозапальних цитокінів. Найбільш виражені зміни виявлені при комплексній
гіперплазії ендометрію. Запальний процес в урогенітальної системі сприяє більш вираженому зростанню рівня
цитокінів в маткових змивах. Оцінка вираженості змін в рівні цитокінів маткових змивів може використовуватися
в якості додаткового критерію, що характеризує гіперплазії ендометрію, для оцінки формування запальних
змін в ендометрії при його гіперплазії і для оцінки прогнозу перебігу гіперплазій.Levels of proinflammatory cytokines IL-1ß, IL-6 and TNF-α in uterine lavage fluid of women with different
types of endometrial hyperplasia were studied. It is established that the formation of endometrial hyperplasia
is associated with activation of proinflammatory cytokines. The most intensive changes were found in complex
endometrial hyperplasia. Inflammation in the urogenital system leads to more intensive increase of cytokines
level in the uterine washout. Investigation of changes in cytokines levels in uterine lavage fluid can be used as an
additional criterion for characteristics of endometrial hyperplasia, to assess the formation of inflammatory changes
in the endometrium and for prognosis of hyperplasia
Cyber-physical energy systems modeling, test specification, and co-simulation based testing
The gradual deployment of intelligent and coordinated devices in the electrical power system needs careful investigation of the interactions between the various domains involved. Especially due to the coupling between ICT and power systems a holistic approach for testing and validating is required. Taking existing (quasi-) standardised smart grid system and test specification methods as a starting point, we are developing a holistic testing and validation approach that allows a very flexible way of assessing the system level aspects by various types of experiments (including virtual, real, and mixed lab settings). This paper describes the formal holistic test case specification method and applies it to a particular co-simulation experimental setup. The various building blocks of such a simulation (i.e., FMI, mosaik, domain-specific simulation federates) are covered in more detail. The presented method addresses most modeling and specification challenges in cyber-physical energy systems and is extensible for future additions such as uncertainty quantification
- …