318 research outputs found

    Scientific research on animal biodiversity is systematically biased towards vertebrates and temperate regions.

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    Over the last 25 years, research on biodiversity has expanded dramatically, fuelled by increasing threats to the natural world. However, the number of published studies is heavily weighted towards certain taxa, perhaps influencing conservation awareness of and funding for less-popular groups. Few studies have systematically quantified these biases, although information on this topic is important for informing future research and conservation priorities. We investigated: i) which animal taxa are being studied; ii) if any taxonomic biases are the same in temperate and tropical regions; iii) whether the taxon studied is named in the title of papers on biodiversity, perhaps reflecting a perception of what biodiversity is; iv) the geographical distribution of biodiversity research, compared with the distribution of biodiversity and threatened species; and v) the geographical distribution of authors' countries of origin. To do this, we used the search engine Web of Science to systematically sample a subset of the published literature with 'biodiversity' in the title. In total 526 research papers were screened-5% of all papers in Web of Science with biodiversity in the title. For each paper, details on taxonomic group, title phrasing, number of citations, study location, and author locations were recorded. Compared to the proportions of described species, we identified a considerable taxonomic weighting towards vertebrates and an under-representation of invertebrates (particularly arachnids and insects) in the published literature. This discrepancy is more pronounced in highly cited papers, and in tropical regions, with only 43% of biodiversity research in the tropics including invertebrates. Furthermore, while papers on vertebrate taxa typically did not specify the taxonomic group in the title, the converse was true for invertebrate papers. Biodiversity research is also biased geographically: studies are more frequently carried out in developed countries with larger economies, and for a given level of species or threatened species, tropical countries were understudied relative to temperate countries. Finally, biodiversity research is disproportionately authored by researchers from wealthier countries, with studies less likely to be carried out by scientists in lower-GDP nations. Our results highlight the need for a more systematic and directed evaluation of biodiversity studies, perhaps informing more targeted research towards those areas and taxa most depauperate in research. Only by doing so can we ensure that biodiversity research yields results that are relevant and applicable to all regions and that the information necessary for the conservation of threatened species is available to conservation practitioners

    Some of the ecological effects of a small inter-basin water transfer on the receiving reaches of the upper Berg River, Western Cape

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    Bibliography: pages 113-129.Inter-basin water transfer (IBT) is defined as the transfer of water from one geographically isolated river catchment, sub-catchment or river reach, to another. Thus, one river becomes a donor, and another the recipient. They are joined by a range of possible transfer routes. In many cases either or both the donor and recipient rivers are impounded. The volumes of water transferred and the operational criteria for IBT schemes vary considerably. This study produced a review of the literature dealing with the ecological (physical, chemical and biological) effects of IBTs. The review highlighted the fact that much of the information available is conceptual, and provides few data collected from systems affected by transfer schemes. The main objective of this study was, therefore, to collect data from a donor and recipient river of a small IBT scheme in the Western Cape, the Riviersonderend-Berg-Eerste River Government Water Scheme (RBEGS). The donor river, the Riviersonderend, is impounded by the Theewaterskloof Dam. Water from this reservoir is transferred through a tunnel to the upper reaches of the Berg River, and then on to the Cape Metropolitan Area (CMA). Approximately 38-45% of the water utilised in the CMA is transferred from Theewaterskloof. The release of water into the upper Berg is f, for irrigation in the upper catchment, and for use by a rainbow trout farm downstream of the outlet

    AN EXPLORATORY STUDY OF LONG SUPPLY CHAIN COMPETITION: SELECTED CASES IN THE SOUTH AFRICAN AEROSPACE SECTOR

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    <p>ENGLISH ABSTRACT: This article investigates how supply chains, especially long supply chains, compete in the South African aerospace industry. A multiple case study methodology is employed, involving six selected firms. Semi-structured interviews provide the primary source of data. Multiple case analysis identifies similarities in competitive dimension criteria for supplier-firm and customer-firm units in the supply chain. Results indicate that supplier-firm units compete on the basis of speed, dependability, quality, flexibility, and cost. Customer-firm units compete on the basis of speed, quality, and flexibility. The results also identify focus areas for future research into how long supply chains compete in the South African aerospace industry.</p><p>AFRIKAANSE OPSOMMING: Hierdie artikel ondersoek hoe voorsieningskettings, veral uitgerekte kettings, meeding in die Suid-Afrikaanse lugvaartindustrie. ‘n Meervoudige gevallestudie-metodologie is gevolg waartydens ses ondernemings bestudeer is. Semi-gestruktureerde onderhoude was die primĂȘre bron van data. Meervoudige gevalle-analise identifiseer ooreenkomste in die mededingingskriteria vir leweransiers- en kliĂ«ntefirmas. Die resultate toon dat leweransiers kompeteer op spoed, betroubaarheid, kwaliteit, aanpasbaarheid en koste. KliĂ«ntefirmas ding mee op grond van spoed, kwaliteit en aanpasbaarheid. Die resultate identifiseer fokusareas vir verdere navorsing op hierdie terrein.</p&gt

    FORECASTING NEW PRODUCT SALES

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    <p>ENGLISH ABSTRACT: This paper tests the accuracy of using Linear regression, Logistics regression, and Bass curves in selected new product rollouts, based on sales data. The selected new products come from the electronics and electrical engineering and information and communications technology industries. The eight selected products are: electronic switchgear, electric motors, supervisory control and data acquisition systems, programmable logic controllers, cell phones, wireless modules, routers, and antennas. We compare the Linear regression, Logistics regression and Bass curves with respect to forecasting using analysis of variance. The accuracy of these three curves is studied and conclusions are drawn. We use an expert panel to compare the different curves and provide lessons for managers to improve forecasting new product sales. In addition, comparison between the two industries is drawn, and areas for further research are indicated.</p><p>AFRIKAANSE OPSOMMING: Hierdie artikel toets die akkuraatheid van die gebruik van linĂȘere regressie, logistiese regressie en Bass-krommes by die bekendstelling van nuwe produkte gebaseer op verkoopsdata. Die geselekteerde nuwe produkte is uit die elektriese en elektroniese asook informasietegnologie- en kommunikasie bedrywe. LinĂȘere regressie, logistiese regressie en Bass-krommes word vergelyk ten opsigte van vooruitskatting deur variansie te ontleed. Die akkuraatheid word ontleed en gevolgtrekkings gemaak. Die doel is om vooruitskatting van nuwe produkverkope te verbeter.</p&gt

    Detection of functional PTEN lipid phosphatase protein and enzyme activity in squamous cell carcinomas of the head andeck, despite loss of heterozygosity at this locus

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    The human tumour suppressor gene PTEN located at 10q23 is mutated in a variety of tumour types particularly metastatic cases and in the germline of some individuals with Cowdens cancer predisposition syndrome. We have assessed the status of PTEN and associated pathways in cell lines derived from 19 squamous cell carcinomas of the head and neck. Loss of heterozygosity is evident at, or close to the PTEN gene in 5 cases, however there were no mutations in the remaining alleles. Furthermore by Western analysis PTEN protein levels are normal in all of these SCC-HN tumours and cell lines. To assess the possibility that PTEN may be inactivated by another mechanism, we characterized lipid phosphatase levels and from a specific PIP3 biochemical assay it is clear that PTEN is functionally active in all 19 human SCCs. Our data strongly suggest the possibility that a tumour suppressor gene associated with development of SCC-HN, other than PTEN, is located in this chromosomal region. This gene does not appear to be MXI-1, which has been implicated in some other human tumour types. PTEN is an important negative regulator of PI3Kinase, of which subunit alpha is frequently amplified in SCC-HN. To examine the possibility that PI3K is upregulated by amplification in this tumour set we assessed the phosphorylation status of Akt, a downstream target of PI3K. In all cases there is no detectable increase in Akt phosphorylation. Therefore there is no detectable defect in the PI3K pathway in SCC-HN suggesting that the reason for 3q26.3 over-representation may be due to genes other than PI3K110α. © 2001 Cancer Research Campaign http://www.bjcancer.co

    TCT-294: Long-Term (Three Years) Follow-Up of the Patients with Multiple Sirolimus Eluting Stent Implantation (Full-metal Jacket Patients)

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    1. The cost, usability and power efficiency of available wildlife monitoring equipment currently inhibits full ground-level coverage of many natural systems. Developments over the last decade in technology, open science, and the sharing economy promise to bring global access to more versatile and more affordable monitoring tools, to improve coverage for conservation researchers and managers. 2. Here we describe the development and proof-of-concept of a low-cost, small-sized and low-energy acoustic detector: 'AudioMoth'. The device is open-source and programmable, with diverse applications for recording animal calls or human activity at sample rates of up to 384kHz. We briefly outline two ongoing real-world case studies of large-scale, long-term monitoring for biodiversity and exploitation of natural resources. These studies demonstrate the potential for AudioMoth to enable a substantial shift away from passive continuous recording by individual devices, towards smart detection by networks of devices flooding large and inaccessible ecosystems. 3. The case studies demonstrate one of the smart capabilities of AudioMoth, to trigger event logging on the basis of classification algorithms that identify specific acoustic events. An algorithm to trigger recordings of the New Forest cicada (Cicadetta montana) demonstrates the potential for AudioMoth to vastly improve the spatial and temporal coverage of surveys for the presence of cryptic animals. An algorithm for logging gunshot events has potential to identify a shotgun blast in tropical rainforest at distances of up to 500 m, extending to 1km with continuous recording. 4. AudioMoth is more energy efficient than currently available passive acoustic monitoring (PAM) devices, giving it considerably greater portability and longevity in the field with smaller batteries. At a build cost of ~US$43 per unit, AudioMoth has potential for varied applications in large-scale, long-term acoustic surveys. With continuing developments in smart, energy-efficient algorithms and diminishing component costs, we are approaching the milestone of local communities being able to afford to remotely monitor their own natural resources
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