600 research outputs found
Crops of the West African Semi-Arid Tropics
This review deals with three aspects, i.e., ecology,
cultivation, and diseases and pests, of 23 crops which are grown in the West African Semi-Arid Tropics. These crops form six groups: cereals, legumes, roots and tubers, vegetables, fibres, and other crops.
The review no doubt has many errors. For these I express my
apologies and hope that they would be brought to my attention so that correction can be made
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Rethinking energy security and services in practice: national vulnerability and three energy pathways in Tajikistan
To help answer questions about availability, accessibility, sustainability and other dimensions of energy security, the vulnerability approach concentrates the attention of policymakers on the assessment of risks associated with natural, technical, political and economic factors. This understanding, combined with a focus on energy services (e.g. lighting, heating, telecommunications, mobility, etc.) helps to prioritize actions to achieve the goal of energy security. This paper conceptualizes energy security as low vulnerability of vital energy systems and sustained provision of modern energy services. Taking Tajikistan as a case, this paper highlights key vulnerabilities including neglect of environmental conditions, insufficient energy production capacity, unreliable and expensive energy imports, dwindling power infrastructure causing technical and economic losses, inadequate transparency in the power sector, lack of regional cooperation in energy and water resources sharing, and inadequate financial resources to address these challenges. Three major proposals presented by the World Bank, the United Nations Development Program, and the Government of Tajikistan to achieve energy security in Tajikistan are evaluated. Specifically, they lack a focus on energy services and therefore overlook people's socio-cultural context and appropriate energy needs. This paper highlights energy services as critical to people’s wellbeing and socio-economic development
Co-Produced Research Supports Pastoralists to Pursue Transformative Social and Ecological Change in Rangelands
Over the last two decades, pastoralists and researchers have formed powerful alliances to transform how we think about and do research-with-action in rangelands. These alliances promote faster learning about problems and their potential solutions by bringing together diverse partners and their different ways of understanding important issues. They also ensure research is fully relevant to real problems, so it supports pastoralists to act on both old and new issues that they face. While these approaches can be contentious when perspectives and experiences do not align, team members are finding them transformative, if they commit to working together over the long term.
Based on a long history of participatory research approaches in the social sciences, these alliances are now inter- and trans-disciplinary, spread throughout the sciences. This paper uses six case studies to explore the experience of teams who have used this research-with-action approach in the rangelands of Kenya, Tanzania, Mongolia, Tajikistan, Afghanistan, Spain and the US. These teams developed and implemented this approach not in halls of academia, but in equal pastoralist-researcher partnerships by creating full co-learning and democratized processes together. These teams then purposely built the capacity of all stakeholders to act together to promote desired change. The case studies integrate diverse knowledges at multiple scales into collective ‘learning and doing’ teams composed of pastoral peoples, policy makers, scientists, business people, and others. This process ensures a broad range of understandings and interpretations form the foundation of the actions and adaptations taken by actors across landscapes and scales. The approach contributes to the resilience of place-based social-ecological systems in rangelands by avoiding top-down, one-size-fits-all approaches. Uniting these ideas and practices has allowed research-with-action to become truly transformative, by accelerating the capacity of all stakeholders to learn and act more effectively
Medicinal Plant Use and Health Sovereignty: Findings from the Tajik and Afghan Pamirs
Medicinal plants are indicators of indigenous
knowledge in the context of political volatility and sociocultural
and ecological change in the Pamir Mountains of
Afghanistan and Tajikistan. Medicinal plants are the
primary health care option in this region of Central Asia.
The main objective of this paper is to demonstrate that
medicinal plants contribute to health security and sovereignty
in a time of instability. We illustrate the nutritional
as well as medicinal significance of plants in the daily
lives of villagers. Based on over a decade and half of
research related to resilience and livelihood security, we
present plant uses in the context of mountain communities.
Villagers identified over 58 cultivated and noncultivated
plants and described 310 distinct uses within
63 categories of treatment and prevention. Presence of
knowledge about medicinal plants is directly connected to
their use
Conservation agriculture for sustainable and resilient agriculture: global status, prospects and challenges
This chapter discusses the following topics: conservation agriculture as the way forward for sustainable agricultural production; definition and concept of conservation agriculture; and the global history, current status and prospects of conservation agriculture. The chapter also includes reports of research studies conducted on: soil and water conservation; soil quality; rainwater use efficiency; nutrient use efficiency; input use efficiency; insect-pest, disease and weed dynamics; crop productivity; climate change mitigation and adaptation; benefits at ecosystem level; and farm profitabilit
Parent and child agreement for acute stress disorder, post-traumatic stress disorder and other psychopathology in a prospective study of children and adolescents exposed to single-event trauma
Examining parent-child agreement for Acute Stress Disorder (ASD) and Post-Traumatic Stress Disorder (PTSD) in children and adolescents is essential for informing the assessment of trauma-exposed children, yet no studies have examined this relationship using appropriate statistical techniques. Parent-child agreement for these disorders was examined by structured interview in a prospective study of assault and motor vehicle accident (MVA) child survivors, assessed at 2-4 weeks and 6 months post-trauma. Children were significantly more likely to meet criteria for ASD, as well as other ASD and PTSD symptom clusters, based on their own report than on their parent's report. Parent-child agreement for ASD was poor (Cohen's κ = -.04), but fair for PTSD (Cohen's κ = .21). Agreement ranged widely for other emotional disorders (Cohen's κ = -.07-.64), with generalised anxiety disorder found to have superior parent-child agreement (when assessed by phi coefficients) relative to ASD and PTSD. The findings support the need to directly interview children and adolescents, particularly for the early screening of posttraumatic stress, and suggest that other anxiety disorders may have a clearer presentation post-trauma
Nonlinear Instability in a Semiclassical Problem
We consider a nonlinear evolution problem with an asymptotic parameter and
construct examples in which the linearized operator has spectrum uniformly
bounded away from Re z >= 0 (that is, the problem is spectrally stable), yet
the nonlinear evolution blows up in short times for arbitrarily small initial
data.
We interpret the results in terms of semiclassical pseudospectrum of the
linearized operator: despite having the spectrum in Re z < -c < 0, the
resolvent of the linearized operator grows very quickly in parts of the region
Re z > 0. We also illustrate the results numerically
Monoclonal Antibodies to Distinct Regions of Human Myelin Proteolipid Protein Simultaneously Recognize Central Nervous System Myelin and Neurons of Many Vertebrate Species
Myelin proteolipid protein (PLP), the major protein of mammalian CNS myelin, is a member of the proteolipid gene family (pgf). It is an evolutionarily conserved polytopic integral membrane protein and a potential autoantigen in multiple sclerosis (MS). To analyze antibody recognition of PLP epitopes in situ, monoclonal antibodies (mAbs) specific for different regions of human PLP (50–69, 100–123, 139–151, 178–191, 200–219, 264–276) were generated and used to immunostain CNS tissues of representative vertebrates. mAbs to each region recognized whole human PLP on Western blots; the anti-100–123 mAb did not recognize DM-20, the PLP isoform that lacks residues 116–150. All of the mAbs stained fixed, permeabilized oligodendrocytes and mammalian and avian CNS tissue myelin. Most of the mAbs also stained amphibian, teleost, and elasmobranch CNS myelin despite greater diversity of their pgf myelin protein sequences. Myelin staining was observed when there was at least 40% identity of the mAb epitope and known pgf myelin proteins of the same or related species. The pgf myelin proteins of teleosts and elasmobranchs lack 116–150; the anti-100–123 mAb did not stain their myelin. In addition to myelin, the anti-178– 191 mAb stained many neurons in all species; other mAbs stained distinct neuron subpopulations in different species. Neuronal staining was observed when there was at least approximately 30% identity of the PLP mAb epitope and known pgf neuronal proteins of the same or related species. Thus, anti-human PLP epitope mAbs simultaneously recognize CNS myelin and neurons even without extensive sequence identity. Widespread anti-PLP mAb recognition of neurons suggests a novel potential pathophysiologic mechanism in MS patients, i.e., that anti-PLP antibodies associated with demyelination might simultaneously recognize pgf epitopes in neurons, thereby affecting their functions
An excess power statistic for detection of burst sources of gravitational radiation
We examine the properties of an excess power method to detect gravitational
waves in interferometric detector data. This method is designed to detect
short-duration (< 0.5 s) burst signals of unknown waveform, such as those from
supernovae or black hole mergers. If only the bursts' duration and frequency
band are known, the method is an optimal detection strategy in both Bayesian
and frequentist senses. It consists of summing the data power over the known
time interval and frequency band of the burst. If the detector noise is
stationary and Gaussian, this sum is distributed as a chi-squared (non-central
chi-squared) deviate in the absence (presence) of a signal. One can use these
distributions to compute frequentist detection thresholds for the measured
power. We derive the method from Bayesian analyses and show how to compute
Bayesian thresholds. More generically, when only upper and/or lower bounds on
the bursts duration and frequency band are known, one must search for excess
power in all concordant durations and bands. Two search schemes are presented
and their computational efficiencies are compared. We find that given
reasonable constraints on the effective duration and bandwidth of signals, the
excess power search can be performed on a single workstation. Furthermore, the
method can be almost as efficient as matched filtering when a large template
bank is required. Finally, we derive generalizations of the method to a network
of several interferometers under the assumption of Gaussian noise.Comment: 22 pages, 6 figure
A new method for assessing content validity in model-based creation and iteration of ehealth interventions
Background: The advent of eHealth interventions to address psychological concerns and health behaviors has created new opportunities, including the ability to optimize the effectiveness of intervention activities and then deliver these activities consistently to a large number of individuals in need. Given that eHealth interventions grounded in a well-delineated theoretical model for change are more likely to be effective and that eHealth interventions can be costly to develop, assuring the match of final intervention content and activities to the underlying model is a key step. We propose to apply the concept of 'content validity' as a crucial checkpoint to evaluate the extent to which proposed intervention activities in an eHealth intervention program are valid (eg, relevant and likely to be effective) for the specific mechanism of change that each is intended to target and the intended target population for the intervention.
Objective: The aims of this paper are to define content validity as it applies to model-based eHealth intervention development, to present a feasible method for assessing content validity in this context, and to describe the implementation of this new method during the development of a Web-based intervention for children.
Methods: We designed a practical 5-step method for assessing content validity in eHealth interventions that includes defining key intervention targets, delineating intervention activity-target pairings, identifying experts and using a survey tool to gather expert ratings of the relevance of each activity to its intended target, its likely effectiveness in achieving the intended target, and its appropriateness with a specific intended audience, and then using quantitative and qualitative results to identify intervention activities that may need modification. We applied this method during our development of the Coping Coach Web-based intervention for school-age children.
Results: In the evaluation of Coping Coach content validity, 15 experts from five countries rated each of 15 intervention activity-target pairings. Based on quantitative indices, content validity was excellent for relevance and good for likely effectiveness and age-appropriateness. Two intervention activities had item-level indicators that suggested the need for further review and potential revision by the development team.
Conclusions: This project demonstrated that assessment of content validity can be straightforward and feasible to implement and that results of this assessment provide useful information for ongoing development and iterations of new eHealth interventions, complementing other sources of information (eg, user feedback, effectiveness evaluations). This approach can be utilized at one or more points during the development process to guide ongoing optimization of eHealth interventions
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