3,075 research outputs found

    Title registration for a systematic review: Access to electricity for improving health, education and welfare in low- and middle-income countries: a systematic review

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    As of 2013, about 1.2 billion people or about one-sixth of the world’s population and mostly poor, lack access to electricity.1 The majority of people without access to electricity are concentrated in rural areas (about 83%).2 The case for energy as a key driver of economic activities is well documented in available literature (Khandker, Barnes, & Samad, 2012). Energy services are considered important for productivity, income, health, education, potable water and communication services (United Nations Development Programme [UNDP], 2005). The global population without access to electricity is concentrated in Sub-Saharan Africa, South Asia, and to a lesser extent in East Asia and the Pacific. In addition to the population that does not have access to electricity, up to a billion people, especially in developing countries, are subject to unreliable and low quality of power supply resulting in outages and brownouts and therefore, reduced benefits from electricity use. Even where electricity is within reach, inability to pay for an electricity connection and ongoing consumption is a significant barrier for many. Low connection rates are particularly prevalent among poorer households. The World Bank Group made a first attempt at investigating the welfare gains associated with electricity access in 2008 (IEG, 2008). This study proposes to update and expand the knowledge on the topic through a systematic review of impact evaluations that have addressed the linkage between access to electricity and health, education and welfare outcomes

    Diagnosing Bone Fracture to Assess Early Hominin Behaviour, Meat-Eating, and Socioecology at FLK-Zinjanthropus, Olduvai Gorge, Tanzania

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    This study develops a fractographic method to diagnose hammerstone- and carnivore induced fracture. This is important because interpretations of hominin entry into the carnivore guild and evolution of meat-eating are based on rare tool and tooth marks in Oldowan (2.5-1.8mya) fossil assemblages. Consequently, estimating hominin and carnivore involvement is difficult, and questions remain about Oldowan hominin’s position in the carnivore guild and socioecology. One aspect of bone damage, fracture surfaces, is ubiquitous, but largely unstudied. The fractographic (study of fracture surfaces) method is based on fracture principals, particularly how differences in static- and impact-loading affect material response and fracture features resulting from loading extremes. The method is applied to analysis of fracture features in a) the Amboseli Hyaena Den assemblage, b) an experimental hammerstone-broken assemblage, c) a Plio-Pleistocene assemblage previously interpreted as a carnivore accumulation, FLK-NN2 (Olduvai Gorge), and d) the zooarchaeological assemblage from FLK-Zinj, (Olduvai Gorge). This is the first zooarchaeological/taphonomic study to demonstrate that a) static and impact fracture differ fundamentally in applied load size and material responses to loading extremes, b) impact-forces are significantly greater than the maximum carnivore bite-force, c) cones, incipient flakes, radiating cracks, and lateral stress features are characteristic of impact fracture, and e) Oldowan hominins at FLK-Zinj were responsible for breakage of 54% of the limb assemblage (a 37% – 40% increase over estimates based on percussion marks). The socioecological implications of the habitual transport of food from death and/or kill sites to secondary locations are explored by examining reasons why social carnivores transport food. Aspects of modern carnivore behaviour suggest general mammalian constraints that may have predicated food transport by early Homo. Early Homo food transport behaviour was structured by anti-predator defense strategies associated with a) foraging in an open habitat rich with competing predators, b) the lack of masticatory and digestive apparatus to quickly consume animal tissue, and c) the presence of altricial young in the hominin group

    Bovid mortality patterns from Kanjera South, Homa Peninsula, Kenya and FLK-Zinj, Olduvai Gorge, Tanzania: Evidence for habitat mediated variability in Oldowan hominin hunting and scavenging behavior

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    The archaeological record has documented Oldowan hominin occupation of habitats ranging from open grasslands to riparian forest by 2.0 Ma. Despite this we have a poor understanding of whether hominin foraging behavior varied in different environmental settings. We compared bovid mortality profiles from the two largest Oldowan zooarchaeological samples, one from a grassland (Excavation 1, Kanjera South, Kenya) and another from a woodland (FLK Zinj, Olduvai Gorge, Tanzania) with bovid mortality samples created by African carnivores in different habitats. Kanjera hominins frequently had early access, likely through hunting, to small (size 1 ≀ 23 kg and size 2 = 24–112 kg) juvenile bovids, creating a mortality pattern similar to that created by grassland dwelling carnivores. Kanjera hominins had more mixed access to large (size 3 = 113–340 kg), often juvenile, bovids and frequently scavenged heads. In contrast, previous work has shown that the few small bovids at FLK-Zinj were predominantly older individuals. Prime adults dominated the FLK-Zinj large bovid sample, leading to a mortality pattern similar to that created by carnivores occupying more closed habitats. Variation in bovid body size and mortality profiles between these archaeological assemblages may reflect the challenges of acquiring fauna in open versus closed habitats with a simple hunting toolkit. The heterogeneous woodland habitat of FLK-Zinj would have provided more opportunities to ambush prey, whereas on grasslands with more limited concealment opportunities Kanjera hominins focused their efforts on vulnerable juvenile prey, some likely acquired after short chases

    Old stones’ song—second verse: use-wear analysis of rhyolite and fenetized andesite artifacts from the Oldowan lithic industry of Kanjera South, Kenya

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    This paper investigates Oldowan hominin behavioral ecology through use-wear analysis of artifacts from Kanjera South, Western Kenya. It extends development of our experimental use-wear reference collection and analysis of use-wear on the well preserved and unweathered Oldowan tools from this site to include rhyolite, a non-local material of similar durability to previously studied quartz and quartzite tools, and fenetized andesite, a local material with considerably less durability. Variability in rhyolite and fenetized andesite texture, inclusions, and matrix required enhancement of previous methods so we combine the use of stereoscopic, metallographic, and scanning electron microscopy in this study. This study allows us to begin exploration of the links between specific artifactual raw materials and the materials they were used to process. Data assembled so far suggest that tools fashioned from non-local and local stone were, with one possible exception, used to process similar materials. Additionally, experiments carried out with replicas of tools made of rhyolite and fenetized andesite confirm interpretation of reduction sequences that tools made of less durable local material had a shorter use-life and were used expediently compared to the more durable non-local quartz, quartzite, and rhyolite. These new data improve our understanding, of the functional needs, behavioral solutions, and cognitive capacities of Oldowan hominins. Finally, these data show how use-wear analysis, combined with lithic raw material and lithic technology, can be a powerful means for evaluating two key points for human evolution: long-term memory, and planning

    Microbial micropatches within microbial hotspots

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    © 2018 Dann et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The spatial distributions of organism abundance and diversity are often heterogeneous. This includes the sub-centimetre distributions of microbes, which have ‘hotspots’ of high abundance, and ‘coldspots’ of low abundance. Previously we showed that 300 ÎŒl abundance hotspots, coldspots and background regions were distinct at all taxonomic levels. Here we build on these results by showing taxonomic micropatches within these 300 ÎŒl microscale hotspots, coldspots and background regions at the 1 ÎŒl scale. This heterogeneity among 1 ÎŒl subsamples was driven by heightened abundance of specific genera. The micropatches were most pronounced within hotspots. Micropatches were dominated by Pseudomonas, Bacteroides, Parasporobacterium and Lachnospiraceae incertae sedis, with Pseudomonas and Bacteroides being responsible for a shift in the most dominant genera in individual hotspot subsamples, representing up to 80.6% and 47.3% average abundance, respectively. The presence of these micropatches implies the ability these groups have to create, establish themselves in, or exploit heterogeneous microenvironments. These genera are often particle-associated, from which we infer that these micropatches are evidence for sub-millimetre aggregates and the aquatic polymer matrix. These findings support the emerging paradigm that the microscale distributions of planktonic microbes are numerically and taxonomically heterogeneous at scales of millimetres and less. We show that microscale microbial hotspots have internal structure within which specific local nutrient exchanges and cellular interactions might occur

    Combining GPS, GIS, and Accelerometry: Methodological Issues in the Assessment of Location and Intensity of Travel Behaviors

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    Background: Global positioning systems (GPS), geographic information systems (GIS), and accelerometers are powerful tools to explain activity within a built environment, yet little integration of these tools has taken place. This study aimed to assess the feasibility of combining GPS, GIS, and accelerometry to understand transport-related physical activity (TPA) in adults. Methods: Forty adults wore an accelerometer and portable GPS unit over 7 consecutive days and completed a demographics questionnaire and 7-day travel log. Accelerometer and GPS data were extracted for commutes to/from workplace and integrated into a GIS database. GIS maps were generated to visually explore physical activity intensity, GPS speeds and routes traveled. Results: GPS, accelerometer, and survey data were collected for 37 participants. Loss of GPS data was substantial due to a range of methodological issues, such as low battery life, signal drop out, and participant noncompliance. Nonetheless, greater travel distances and significantly higher speeds were observed for motorized trips when compared with TPA. Conclusions: Pragmatic issues of using GPS monitoring to understand TPA behaviors and methodological recommendations for future research were identified. Although methodologically challenging, the combination of GPS monitoring, accelerometry and GIS technologies holds promise for understanding TPA within the built environment

    Evaluation of electrical signals in pine trees in a mediterranean forest ecosystem

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    This is an Accepted Manuscript of an article published by Taylor & Francis in Plant Signaling and Behaviour on 2020, available online: http://www.tandfonline.com/10.1080/15592324.2020.1795580[EN] Electric potential differences in living plants are explained by theories based on sap flow. In order to acquire more advanced knowledge about the spatial distribution of these electric potential measures in trees, this research aims to analyze electrical signals in a population of Aleppo pines (Pinus halepensisMill.) in a representative Mediterranean forest ecosystem. The specific research objective is to assess some of the most significant factors that influence the distribution pattern of those electric signals: tree age, measurement type and electrode placement. The research has been conducted in representative forest stands, obtaining measurements of different representative trees. After a statistical evaluation of the obtained results, the main conclusions of our research are: A.Tree maturity influences directly on electric potential. B.Maximum electrical signals can be measured in young pines showing values of 0.6 V and 0.6 mu A for voltage and current, respectively. C.The distribution patterns of both voltage and short-circuit current depending on electrode placement are uniform.Zapata, R.; Oliver Villanueva, JV.; Lemus ZĂșñiga, LG.; Luzuriaga, JE.; Mateo Pla, MÁ.; UrchueguĂ­a Schölzel, JF. (2020). Evaluation of electrical signals in pine trees in a mediterranean forest ecosystem. Plant Signaling and Behaviour (Online). 15(10):1-9. https://doi.org/10.1080/15592324.2020.1795580S191510I. Further experiments on the more important physiological changes induced in the human economy by change of climate. (1873). Proceedings of the Royal Society of London, 21(139-147), 1-10. doi:10.1098/rspl.1872.0002Darwin, C. (1875). 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 Merka, P. (2019). Fully Inkjet-Printed CuO Sensor on Flexible Polymer Substrate for Alcohol Vapours and Humidity Sensing at Room Temperature. Sensors, 19(14), 3068. doi:10.3390/s19143068Wang, K., & Zhang, S. (2019). Extracellular electron transfer modes and rate-limiting steps in denitrifying biocathodes. Environmental Science and Pollution Research, 26(16), 16378-16387. doi:10.1007/s11356-019-05117-xDIRECTIVE 1999/5/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 9 March 1999.Prutchi, D., & Norris, M. (2004). Design and Development of Medical Electronic Instrumentation. doi:10.1002/0471681849Woodward, S., & Pearce, R. B. (1988). The role of stilbenes in resistance of Sitka spruce (Picea sitchensis (Bong.) Carr.) to entry of fungal pathogens. Physiological and Molecular Plant Pathology, 33(1), 127-149. doi:10.1016/0885-5765(88)90049-5Mullick, D. B. (1975). A new tissue essential to necrophylactic periderm formation in the bark of four conifers. Canadian Journal of Botany, 53(21), 2443-2457. doi:10.1139/b75-271Abbott, D. T., & Crossley, D. A. (1982). Woody Litter Decomposition Following Clear-Cutting. Ecology, 63(1), 35-42. doi:10.2307/1937028Fensom, D. S. (1963). THE BIOELECTRIC POTENTIALS OF PLANTS AND THEIR FUNCTIONAL SIGNIFICANCE: V. SOME DAILY AND SEASONAL CHANGES IN THE ELECTRICAL POTENTIAL AND RESISTANCE OF LIVING TREES. Canadian Journal of Botany, 41(6), 831-851. doi:10.1139/b63-068Sellin, A. (1991). Variation in sapwood thickness of Picea abies in Estonia depending on the tree age. Scandinavian Journal of Forest Research, 6(1-4), 463-469. doi:10.1080/02827589109382683Rosenvald, K., Ostonen, I., Uri, V., Varik, M., Tedersoo, L., & LĂ”hmus, K. (2012). Tree age effect on fine-root and leaf morphology in a silver birch forest chronosequence. European Journal of Forest Research, 132(2), 219-230. doi:10.1007/s10342-012-0669-7Delgado, A. V., GonzĂĄlez-Caballero, F., Hunter, R. J., Koopal, L. K., & Lyklema, J. (2007). Measurement and interpretation of electrokinetic phenomena. Journal of Colloid and Interface Science, 309(2), 194-224. doi:10.1016/j.jcis.2006.12.07
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