419 research outputs found
Energy Access and Electricity Planning
As developing countries look for ways to achieve sustainable energy services, which is essential to lift people out of poverty, the big challenge centers around providing access for all while avoiding past pitfalls without creating new ones. The reality is that this can only occur if there is a fundamental transformation of energy systems along the entire set of resource to energy service chains - and that will necessitate greater energy efficiency and a bigger role for renewables in the global energy mix energy. Competitive and private sector dominated energy markets rely on clear and consistent government energy-environment policies to align their investment decisions with sustainable development objectives. This paper tries to shed light on how developing countries can carry out energy planning by reviewing the available methodologies and tools, including their potential to integrate rural energy access and encourage the uptake of renewable energy technologies. It also probes how investment needs and cost-effectiveness are reflected in different analytic and planning tools - with a case study on Ethiopia. And it examines the interaction of energy planning and scenario development and how these are applied to informed policy making. The findings suggest that energy planning is essential and feasible. However, support is required to improve data collection and access, develop open accessible modelling tools, and build sustainable national capacity to undertake plannin
Desalination using renewable energy sources on the arid islands of South Aegean Sea
Water and energy supply are strongly interrelated and their efficient management is crucial for a sustainable future. Water and energy systems on several Greek islands face a number of pressing issues. Water supply is problematic as regards both to the water quality and quantity. There is significant lack of water on several islands and this is mainly dealt with tanker vessels which transport vast amounts of water from the mainland. At the same time island energy systems are congested and rely predominanty on fossil fuels, despite the abundant renewable energy potential. These issues may be addressed by combining desalination and renewable energy technologies. It is essential to analyse the feasibility of this possibility. This study focuses on developing a tool capable of designing and optimally sizing desalination and renewable energy units. Several parameters regarding an island's water demandand the desalination's energy requirements are taken into account as well as input data which concern technological performance, resource availability and economic data. The tool is applied on three islands in the South Aegean Sea, Patmos (large), Lipsoi (medium) ad Thirasia (small). Results of the modelling exercise show that the water selling price ranges from 1.45 euro/m^3 for the large island, while the corresponding value is about 2.6 euro/m^3 for the small island, figures significantly lower than the current water cost (7-9 euro/m^3)
Dairy Farm Business Summary: Central Valleys Region 1997
E.B. 98-12Dairy farm managers throughout New York State have been participating in Cornell Cooperative Extension's farm business summary and analysis program since the early 1950's. Managers of each participating farm business receive a comprehensive summary and analysis of their farm business. The information in this report represents averages of the data submitted from dairy farms in the Central Valleys Region for 1997
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Psychometric properties of discourse measures in aphasia: acceptability, reliability, and validity
BACKGROUND: Discourse in adults with aphasia is increasingly the focus of assessment and therapy research. A broad range of measures is available to describe discourse, but very limited information is available on their psychometric properties. As a result, the quality of these measures is unknown, and there is very little evidence to motivate the choice of one measure over another. AIMS: To explore the quality of a range of discourse measures, targeting sentence structure, coherence, story structure and cohesion. Quality was evaluated in terms of the psychometric properties of acceptability (data completeness and skewness), reliability (inter- and intra-rater), and validity (content, convergent, discriminant and known groups). METHODS & PROCEDURES: Participants with chronic mild-to-moderate aphasia were recruited from community groups. They produced a range of discourses which were grouped into Cinderella and everyday discourses. Discourses were then transcribed orthographically and analyzed using macro- and microlinguistic measures (Story Grammar, Topic Coherence, Local Coherence, Reference Chains and Predicate Argument Structure-PAS). Data were evaluated against standard predetermined criteria to ascertain the psychometric quality of the measures. OUTCOMES & RESULTS: A total of 17 participants took part in the study. All measures had high levels of acceptability, inter- and intra-rater reliability, and had good content validity, as they could be related to a level of the theoretical model of discourse production. For convergent validity, as expected, 8/10 measures correlated with the Western Aphasia Battery-Revised (WAB-R) spontaneous speech scores, and 7/10 measures correlated with the Kissing and Dancing Test (KDT) scores (r ≥ 0.3), giving an overall positive rating for construct validity. For discriminant validity, as predicted, all measures had low correlations with Raven's Coloured Progressive Matrices (RCPM) and WAB-R Auditory Verbal Comprehension scores (r < 0.3), giving an overall positive rating for construct validity. Finally, for known groups validity, all measures indicated a difference between speakers with mild and moderate aphasia except for the Local Coherence measures. Overall, Story Grammar, Topic Coherence, Reference Chains and PAS emerged as the strongest measures in the current study because they achieved the predetermined thresholds for quality in terms of each of the psychometric parameters profiled. CONCLUSIONS & IMPLICATIONS: The current study is the first to psychometrically profile measures of discourse in aphasia. It contributes to the field by identifying Story Grammar, Topic Coherence, Reference Chains and PAS as the most psychometrically robust discourse measures yet profiled with speakers with aphasia. Until further data are available indicating the strength of other discourse measures, caution should be applied when using them
Unraveling the Possible Routes of SARS-COV-2 Invasion into the Central Nervous System
Purpose of Review: To describe the possible neuroinvasion pathways of Severe Acute Respiratory Syndrome-related Coronavirus-2 (SARS-CoV-2), the virus responsible for the Coronavirus disease-19 (Covid-19) pandemic.
Recent Findings: We present data regarding the family of Coronaviruses (CoVs) and the central nervous system (CNS), and describe parallels between SARS-CoV-2 and other members of the family, which have been investigated in more depth and combine these findings with the recent advancements regarding SARS-CoV-2.
Summary: SARS-CoV-2 like other CoVs is neuroinvasive, neurotropic and neurovirulent. Two main pathways of CNS penetration seem to be the strongest candidates, the hematogenous and the neuronal. Τhe olfactory route in particular appears to play a significant role in neuroinvasion of coronaviruses and SARS-CoV-2, as well. However, existing data suggest that other routes, involving the nasal epithelium in general, lymphatic tissue and the CSF may also play roles in SARS-CoV-2 invasion into the CNS
Book Reviews
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Morphological characteristics of motor neurons do not determine their relative susceptibility to degeneration in a mouse model of severe spinal muscular atrophy
Spinal muscular atrophy (SMA) is a leading genetic cause of infant mortality, resulting primarily from the degeneration and loss of lower motor neurons. Studies using mouse models of SMA have revealed widespread heterogeneity in the susceptibility of individual motor neurons to neurodegeneration, but the underlying reasons remain unclear. Data from related motor neuron diseases, such as amyotrophic lateral sclerosis (ALS), suggest that morphological properties of motor neurons may regulate susceptibility: in ALS larger motor units innervating fast-twitch muscles degenerate first. We therefore set out to determine whether intrinsic morphological characteristics of motor neurons influenced their relative vulnerability to SMA. Motor neuron vulnerability was mapped across 10 muscle groups in SMA mice. Neither the position of the muscle in the body, nor the fibre type of the muscle innervated, influenced susceptibility. Morphological properties of vulnerable and disease-resistant motor neurons were then determined from single motor units reconstructed in Thy.1-YFP-H mice. None of the parameters we investigated in healthy young adult mice - including motor unit size, motor unit arbor length, branching patterns, motor endplate size, developmental pruning and numbers of terminal Schwann cells at neuromuscular junctions - correlated with vulnerability. We conclude that morphological characteristics of motor neurons are not a major determinant of disease-susceptibility in SMA, in stark contrast to related forms of motor neuron disease such as ALS. This suggests that subtle molecular differences between motor neurons, or extrinsic factors arising from other cell types, are more likely to determine relative susceptibility in SMA
A Geospatial Assessment of Small-Scale Hydropower Potential in Sub-Saharan Africa
Sub-Saharan Africa has been at the epicenter of an ongoing global dialogue around the issue of energy poverty. More than half of the world’s population without access to modern energy services lives there. It also happens to be a sub-continent with plentiful renewable energy resource potential. Hydropower is one of them, and to a large extent it remains untapped. This study focuses on the technical assessment of small-scale hydropower (0.01–10 MW) in Sub-Saharan Africa. The underlying methodology was based on open source geospatial datasets, whose combination allowed a consistent evaluation of 712,615 km of river network spanning over 44 countries. Environmental, topological, and social constraints were included in the form of constraints in the optimization algorithm. The results are presented on a country and power pool basis
the challenge of energy access in africa
There are multiple dimensions to the problem of energy access in Sub-Saharan Africa, where large shares of population lack a reliable supply of electricity and affordable modern cooking fuels: from insufficient power generation capacity, to difficulties in managing energy infrastructure and attract investments in the sector, to challenges in serving low-income users. Booming populations, urbanization, and ambitions of economic development will all demand more energy. This chapter illustrates the main challenges ahead towards the sustainable development objective of achieving universal access to electricity and clean cooking in the region
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