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Sample records for southern african river

  1. Trends in the Flow Regime of the Southern African Rivers as ...

    African Journals Online (AJOL)

    In an attempt to investigate possible trend in the annual river runoff of 502 rivers in the region of southern Africa, possible trends were first visualized and examined by the use of rescaled adjusted partial sums (RAPS) rather than the actual time series plots of runoff. A simulation experiment of the technique has been ...

  2. Archives: Southern African Journal of Critical Care

    African Journals Online (AJOL)

    Items 1 - 24 of 24 ... Archives: Southern African Journal of Critical Care. Journal Home > Archives: Southern African Journal of Critical Care. Log in or Register to get access to full text downloads.

  3. Review of Southern African Studies

    African Journals Online (AJOL)

    Review of Southern African Studies is a multidisciplinary journal of Arts, Social and Behavioural Sciences. Vol 13, No 1 (2009). DOWNLOAD FULL TEXT Open Access DOWNLOAD FULL TEXT Subscription or Fee Access. Table of Contents. Articles. Health-Care Waste Practices in Selected Health-Care Facilities in Maseru ...

  4. Review of coastal currents in Southern African waters

    CSIR Research Space (South Africa)

    Harris, TFW

    1978-08-01

    Full Text Available A review has been made of existing knowledge of the coastal currents in Southern African waters between Pretoria to Oudtshoorn on the northeast border, and the Orange River on the west coast. These waters have been divided into five sectors...

  5. Southern African AIDS Training Programme.

    Science.gov (United States)

    Dafoe, G H

    1994-01-01

    The Canadian Public Health Association (CPHA) with the Canadian International Development Agency (CIDA), in a little over 2 years, have established a Southern African AIDS Training Programme (SAT) that is effective in developing community-based responses to acquired immunodeficiency syndrome (AIDS). Based in Harare, Zimbabwe, the program provides financial assistance, training, monitoring, and advice and information to 120 project partners. The average grant size is $40,000. In a second phase of the project, SAT will attempt to meet the requests of its partners for more services. Currently, to meet needs for rapid, responsive training, and novel approaches to skill building, SAT has developed a collaborative nongovernmental organization (NGO) initiative, "The School Without Walls". This program identifies and amplifies what has worked effectively for organizations and programs. Other similar organizations and programs learn from these experiences. Site visits, apprenticeships, mentor organizations, and skills-building based on shared problem-diagnosis and resolution are some of the techniques employed. A draft report of the CIDA midterm external evaluation of SAT recommends renewal of the program, resourcing of the program to meet its regional responsibilities, and adoption of "The School Without Walls" as a central strategy for southern Africa.

  6. South African southern ocean research programme

    CSIR Research Space (South Africa)

    SASCAR

    1987-01-01

    Full Text Available This document describes the South African National Antarctic Research Programme's (SANARP) physical, chemical and biological Southern Ocean research programme. The programme has three main components: ecological studies of the Prince Edward Islands...

  7. The environmental communication forum | Goetz | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of Environmental Education. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 5, No 1 (1987) >. Log in or Register to get access to full text downloads.

  8. Book Review: Multilingualism online | Roux | Southern African ...

    African Journals Online (AJOL)

    Southern African Linguistics and Applied Language Studies. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 35, No 2 (2017) >. Log in or Register to get access to full text downloads.

  9. Southern Ocean - South African cooperative research programme.

    CSIR Research Space (South Africa)

    SANCOR

    1979-05-01

    Full Text Available South African research in the Southern Ocean has already produced some important and illuminating results. Most of these efforts, however, were of an individual and uncoordinated nature. Due to increasing interest in the ocean- in South Africa...

  10. Globalisation, transport and HIV | Andrews | Southern African ...

    African Journals Online (AJOL)

    No Abstract Southern African Journal of HIV Medicine Vol. 5 (4) 2004: 41-44. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

  11. Paediatric antiretroviral pharmacology | Patel | Southern African ...

    African Journals Online (AJOL)

    No Abstract Southern African Journal of HIV Medicine Vol. 6 (4) 2005: pp. 8-14. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

  12. Southern African Journal of Environmental Education

    African Journals Online (AJOL)

    The Southern African Journal of Environmental Education (SAJEE) is an accredited and internationally refereed journal. It is published at least once a year, by the Environmental Education Association of Southern Africa (EEASA). The SAJEE aims to publish and report on a wide range of aspects relating to Environmental ...

  13. Southern African Linguistics and Applied Language Studies

    African Journals Online (AJOL)

    Southern African Linguistics and Applied Language Studies publishes articles on a wide range of linguistic topics and acts as a forum for research into ALL the languages of southern Africa, including English and Afrikaans. Original contributions are welcomed on any of the core areas of Linguistics, both theoretical (e.g. ...

  14. Southern African Development Research Network | CRDI - Centre ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    This project will build on lessons learned from an earlier IDRC-supported effort, the Southern African Trade Research Network (SATRN), funded under project 100816. The grant will support a broad-based research network, the Southern Africa Development Research Network (SADRN) with a view to filling some of the gaps ...

  15. Preface | Bekker | Southern African Linguistics and Applied ...

    African Journals Online (AJOL)

    Southern African Linguistics and Applied Language Studies. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 32, No 1 (2014) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. DOWNLOAD FULL TEXT ...

  16. Towards a Southern African English Defining Vocabulary

    African Journals Online (AJOL)

    user

    Towards a Southern African. English Defining Vocabulary*. Lorna Hiles, Department of Afrikaans and Dutch, Stellenbosch University,. Stellenbosch, South Africa (lorna@dictionarian.co.za). Abstract: Controlled defining vocabularies have been used regularly in lexicography since the. 1970s. They are mostly employed in ...

  17. Southern African Journal of Environmental Education: Submissions

    African Journals Online (AJOL)

    Online Submissions. Already have a Username/Password for Southern African Journal of Environmental Education? Go to Login. Need a Username/Password? Go to Registration. Registration and login are required to submit items online and to check the status of current submissions.

  18. Southern African Journal of HIV Medicine

    African Journals Online (AJOL)

    The Southern African Journal of HIV Medicine is a medical journal focused on HIV/AIDS treatment, prevention and related topics relevant to clinical and public health practice. The purpose of the journal is to disseminate original research results and to support high-level learning related to HIV Medicine. It publishes original ...

  19. Globalisation, transport and HIV | Andrews | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 5, No 4 (2004) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected ...

  20. Nailuj | Watson | SAFERE: Southern African Feminist Review

    African Journals Online (AJOL)

    SAFERE: Southern African Feminist Review. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 3, No 2 (1999) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. DOWNLOAD FULL TEXT Open Access ...

  1. Studies of mineralization in South African rivers

    CSIR Research Space (South Africa)

    Hall, GC

    1978-03-01

    Full Text Available Several South African rivers are polluted by mineral salts of diffuse source. This pollution can be related to geological phenomena and to irrigation practices. Mineralization is problematic in that it can render surface waters unsuitable...

  2. Ecological flow requirements for South African rivers

    CSIR Research Space (South Africa)

    Ferrar, AA

    1989-01-01

    Full Text Available This document contains the proceedings of a workshop which was convened to debate the ecological flow requirements of South African rivers. Topics which are discussed include the influence of weirs and impoundments, the quantity requirements...

  3. SAFERE: Southern African Feminist Review

    African Journals Online (AJOL)

    Feminism and Masculinity in an African Capitalist Context: · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Mwenda G. Ntarangwi, 19-32. http://dx.doi.org/10.4314/safere.v3i1.23948 ...

  4. Aspidonepsis (Asclepiadaceae, a new southern African genus

    Directory of Open Access Journals (Sweden)

    A. Nicholas

    1992-10-01

    Full Text Available Aspidonepsis, an endemic southern African genus, is described and compared to the closely allied genus Aspidoglossum. This newly described genus is composed of two subgenera, Aspidonepsis and Unguilobium. consisting of three and two species respectively.  Asclepias diploglossa, A. flava, A. cognata and A. reneensis are transferred to Aspidonepsis. and A. shebae is newly described. All species are discussed, illustrated and a key is given to aid in their identification.

  5. Book Review Roberts Geographic Variation of Southern African Birds

    African Journals Online (AJOL)

    Book Review Roberts Geographic Variation of Southern African Birds: a Guide to the Plumage Variation of 613 Bird Races in Southern Africa By Hugh Chittenden, David Allen and illustrated by Ingrid Weiersbye (2012)

  6. Transport and Impact of Southern African Aerosols

    Science.gov (United States)

    Swap, Robert John

    Atmospheric circulations over southern Africa are responsible for aerosol and trace gas transports. Three major types of low and mid level (surface to 500 hPa) air parcel transports are found during the Southern African Fire-Atmosphere Research Initiative (SAFARI) of August -October of 1992: (1) easterly direct and indirect; (2) westerly direct and indirect; and (3) recirculation within anticyclonic gyres. Air parcel transports off of southern Africa during SAFARI are overwhelmingly to the east (> 95%) and rise once away from the vertical controls of spatially ubiqitous and temporally persistent layers of absolute stability. The remaining westerly transports (~5%) are subsident in nature due to the effective capping of the stable layers. Average daily regional SAFARI air parcel volume transports for ENP approach 2.5 times 10^{14 } m^3/d and 1.6 times 10^{14} m ^3/d for westerly and easterly transports, respectively. Average daily SAFARI depositional fluxes of surface particulates are on the order of 0.15 kg/ha/d and 0.1 kg/ha/d for easterly and westerly transports. Average SAFARI daily depositional fluxes for the following nutritive species, rm K^+, NO_sp {3}{-}, NH_sp{4} {+}, and PO_sp{4} {3-}, range from 0.02 g/ha/d for rm PO_sp{4}{3-} to 0.9 g/ha/d for rm NO_sp{3 }{-} and NH_sp{4 }{+}. Annually, total southern African aerosol mass transports due to the dominant circulations are approximately 135 Mtons, with 29 Mtons transported to the south Atlantic, 45 Mtons to the Indian Ocean and 60 Mtons recirculated over southern Africa. Organic and inorganic geochemical techniques delineate between biomass burning/biogenic debris, industrial and mineral emissions. Average surface particulate concentrations at ENP during SAFARI are approximately 55 mu g/m^3 and range from 40 mug/m^3 to 65 mug/m^3 depending on circulation type. Bulk stable carbon isotope analyses of surface particulates result in signatures characteristic of biogenic (biomass burning/debris (-23 to -28

  7. The Role of South Africa in Southern African Regional Integration ...

    African Journals Online (AJOL)

    This article provides an analysis of the role of the South African state in Southern African regional integration as viewed by the Zimbabwean state, capital and civil society. Their view is that South Africa should forge and sustain better and more equitable relations with the rest of Southern Africa so as to create and sustain a ...

  8. Canadian assistance to southern African utilities to improve operational hydrology

    Energy Technology Data Exchange (ETDEWEB)

    Dyer, L. [SNC Group, Montreal, PQ (Canada)

    1995-12-31

    Various hydroelectric power projects in southern African countries that have benefited from Canadian expertise and assistance under the Southern African Development Community (SADC) AAA.3.4 Hydroelectric Hydrological Assistance Project, were described. The project aims to upgrade the operational hydrology units of the SADC hydroelectric utilities in the Zambezi River Basin, focusing particularly on improving the quality, availability, accessibility and utility of the hydrometric data used for inflow forecasting and inventory purposes. The data is also used for planning and operations. A current usage is to assess the sustainability of the systems implemented under the program. BC Hydro, and the Water Survey of Canada are the principal Canadian agencies involved in providing the technical expertise. Increased confidence in inflow forecasts, increased energy production, reduced loss of water due to unnecessary spilling, improved ability to safely route floods, and to cope with droughts, and improved data for design and dam safety studies are just some of the benefits derived from this example of Canadian technical assistance in the developing countries. 12 refs., 6 tabs., 4 figs.

  9. Seismic imaging of Southern African cratons

    DEFF Research Database (Denmark)

    Soliman, Mohammad Youssof Ahmad

    Cratonic regions are the oldest stable parts of continents that hold most of Earth’s mineral resources. There are several open questions regarding their formation and evolution. In this PhD study, passive source seismic methods have been used to investigate the crustal and lithosphere structures...... of the southern African regions. Some of the main research problems that have been dealt with during this research are about (1) the heterogeneity scale of crustal structure and composition, (2) the depth extent of the cratonic keels and their layering, and (3) the strength of crustal anisotropy. The core...... of this research was based on Ps- and Sp- receiver functions analysis to determine crustal thickness while finite-frequency traveltime tomography is utilized to model 3D heterogeneity in the upper mantle. Combining the two methods provides high vertical and lateral resolution....

  10. Safety of antiretrovirals in pregnancy | Clayden | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 10, No 1 (2009) >. Log in or Register to get access to full text downloads.

  11. Efavirenz in pregnancy | Clayden | Southern African Journal of HIV ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 11, No 2 (2010) >. Log in or Register to get access to full text downloads.

  12. A nurse's perspective on the ART rollout | Tito | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 15, No 1 (2014) >. Log in or Register to get access to full text downloads.

  13. Building on the first decade of ART | Maartens | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 15, No 1 (2014) >. Log in or Register to get access to full text downloads.

  14. Building on the first decade of ART | Maartens | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 15, No 1 (2014) >. Log in or Register to get access to full text downloads.

  15. Reflections on six years in paediatric ART | Moore | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 15, No 1 (2014) >. Log in or Register to get access to full text downloads.

  16. Microsatellite-based characterization of Southern African domestic ...

    African Journals Online (AJOL)

    based study of genetic diversity on southern African pig populations. A total of 351 pigs from three commercial breeds and three indigenous populations were genotyped at 39 loci. Differences among the levels of genetic diversity in populations ...

  17. Southern African Business Review - Vol 13, No 3 (2009)

    African Journals Online (AJOL)

    Academic publishing: Lessons learnt from the Southern African Business Review · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL ... The role of strategic leadership in effective strategy implementation: Perceptions of South African strategic leaders · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  18. Resource centre at the South African museum | Harrison | Southern ...

    African Journals Online (AJOL)

    Southern African Journal of Environmental Education. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 8 (1988) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Resource centre at the South African ...

  19. Competency development of southern African housing officers

    Directory of Open Access Journals (Sweden)

    Munita Dunn

    2013-11-01

    Full Text Available The Report on the Ministerial Committee for the Review of the Provision of StudentHousing at South African Universities (Higher Education and Training, 2011 hasprovided a comprehensive review of residences across several housing functional areas. Inone of the residence management and administration recommendations it stated, “Theprofessionalisation of housing staff is an urgent priority” (p. 141. This coupled with thereport’s estimated “current residence bed shortage of approximately 195 815 beds … witha cost of overcoming this shortage over a period of ten years is estimated at R82.4 billion”(pp. xvii–xviii will mean the hiring and training of hundreds of housing professional staffto meet not only the demand of the additional residence beds but the training of currenthousing staff. In 2010 The Association of College and University Housing Officers –International Southern Africa Chapter (ACUHO-I SAC initiated a Student HousingTraining Institute (SHTI first held in 2011 to meet the demands for professionalisinghousing staff. The SHTI was organised using a competency development model first usedto develop the Association of College and University Housing Officers – International(ACUHO-I James C. Grimm National Housing Training Institute (NHTI held in the US.

  20. The Southern African Development Community in legal historical ...

    African Journals Online (AJOL)

    This article explores the institutional history of the Southern African Development Community (SADC) with a view to isolating the factors and/or forces behind the slow progress of real economic integration in Southern Africa. It finds that SADC's poor track record in delivering on its institutional objectives is attributable to four ...

  1. African Renaissance – A Call to Reality: Southern African ...

    African Journals Online (AJOL)

    Mbeki's own definition of the African Renaissance embraces “marriage of memory and dream, of past and future”. His objective is to free the African mind from the enslavement that colonialism brought, which almost crushed the African soul and distorted, banished, and almost destroyed this memory. It is in this context that I ...

  2. Characteristics of southern California atmospheric rivers

    Science.gov (United States)

    Harris, Sarah M.; Carvalho, Leila M. V.

    2017-05-01

    Atmospheric rivers (ARs) are channels of high water vapor flux that transport moisture from low to higher latitudes on synoptic timescales. In areas of topographical variability, ARs may lead to high-intensity precipitation due to orographic forcing. ARs landfalling along North America's west coast are linked to extreme events including those leading to flooding and landslides. In southern California (SCA), proper AR forecasting is important for regional water resources as well as hazard mitigation and as the area's annual precipitation totals occur from relatively few storms per season, any changes to storm frequency and/or intensity may have dramatic consequences. Yet, as most regional AR studies focus on the Pacific Northwest, there is little information about SCA ARs. We develop an algorithm to identify ARs landfalling on North America's west coast between 1979 and 2013 within total precipitable water reanalysis fields. ARs are then categorized according to landfall region. To determine and differentiate the characteristics and spatial distributions of ARs affecting these areas, we examine lag composites of various atmospheric variables for each landfall region. SCA ARs differ from ARs landfalling farther north in the days prior to landfall with the position and amplitude of a trough offshore from the Asian continent and ridge over Alaska, as well as the displacement and eastward extension of the jet core that potentially guides AR moisture southwards. The relationships between AR landfalls and the El Niño/Southern Oscillation (ENSO), the Madden-Julian Oscillation (MJO), and the Pacific/North American Teleconnection Pattern (PNA) are also investigated.

  3. Southern African advanced fire information system

    CSIR Research Space (South Africa)

    McFerren, G

    2009-05-01

    Full Text Available datasets South Africa Protected Areas OGC WMS/WFS South African Protected Areas of various kinds, curated by South African National Biodiversity Institute Wind speed and direction OGC WMS/WFS Wind conditions last observed and reported by Weather... wherever fire threatens infrastructure. An important priority is the positioning of AFIS as a system for assisting in fire monitoring in protected areas. Here, fire management is key to ensuring preservation of ecosystem health, so fire managers require...

  4. African refugees in the southern Mediterranean

    OpenAIRE

    Lodge, Tom

    2014-01-01

    Between 1960 and 2000, most Africans travelling across the Mediterranean were North Africans by origin, that is, Algerian, Tunisian and Moroccan, moving first to France, and subsequently to Germany, Belgium and the Netherlands, responding to European demand for low skilled and low paid labour. Legal Moroccan emigration between the 1960s and the 2000s had created a diaspora of 2.6 million former Moroccans in Europe. Meanwhile, 700,000 Tunisians were living in France in 2003 (Baldwin-Edwards, 2...

  5. Role of Weddell Sea ice variability in southern African climate

    Science.gov (United States)

    Morioka, Y.; Engelbrecht, F.; Behera, S. K.

    2016-12-01

    A role of interannual sea ice variability in the Weddell Sea on southern African climate is investigated by conducting data analysis and coupled general circulation model (CGCM) experiments. The Weddell Sea ice exhibits a distinct interannual variability during austral summer when the southern African rainfall experiences most of its annual rainfall. The sea ice concentration (SIC) in the Weddell Sea shows a significantly negative correlation with the southern African rainfall during early summer (Nov-Jan). The low SIC anomaly in the Weddell Sea is associated with anticyclonic atmospheric circulation anomalies in the South Atlantic and southern Indian Oceans, which facilitates more moisture advection from the southern Indian Ocean. Composite analysis reveals that the low SIC anomaly in the Weddell Sea is attributed to the increased solar radiation and the northwesterly wind anomaly. This low SIC anomaly, in turn, acts to cause warmer skin temperature and reduce the meridional temperature gradient to the north. This is a favoring condition for sustaining the anticyclonic circulation anomaly in the South Atlantic by enhancing the near-surface atmospheric stability. This intriguing association between the SIC and atmospheric circulation anomalies is also simulated in a series of CGCM experiment, e.g. where the interannual sea surface temperature (SST) variability in the tropics and midlatitudes is suppressed by the monthly climatology of the model. However, in the absence of interannual SST variability over global oceans, the simulated SIC anomaly is much smaller in association with the atmospheric internal variability, called the Southern Annular Mode. These CGCM results suggest that the air-sea-ice interaction in the Weddell Sea has potential impact on the overlying atmosphere in the South Atlantic, which is important for the southern African climate.

  6. Determinants of Foreign Direct Investment in the Southern African ...

    African Journals Online (AJOL)

    This paper examines the determinants of FDI inflows to the Southern African Development Community (SADC)21 using data for the period 1990 -2007. The pooled ordinary least squares and panel least squares methods were used for estimation. The results show that the FDI inflows to SADC are positively and significantly ...

  7. The Honey bee across the curriculum | Hart | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of Environmental Education. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 4 (1987) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  8. Gender inequality: Bad for men's health | Cornell | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 14, No 1 (2013) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should load ...

  9. Resource centre at the South African museum | Harrison | Southern ...

    African Journals Online (AJOL)

    Southern African Journal of Environmental Education. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 8 (1988) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should ...

  10. The status of some southern African nominal species of Cucumaria ...

    African Journals Online (AJOL)

    A full history of four nominal species of southern African dendrochirotid holothurians, namely Cucumaria jageri Lampert, Semperia (= Cueumaria) sykion Lampert, C. insolens Theel and C. sinorbis Cherbonnier, is given and the confusion in their taxonomic status discussed. Morphological differences and habitat selection ...

  11. Post-exposure prophylaxis | Smith | Southern African Journal of HIV ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 2, No 1 (2001) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Post-exposure prophylaxis. C Smith. Abstract.

  12. Running the rat race | Pearce | Southern African Journal of ...

    African Journals Online (AJOL)

    Southern African Journal of Anaesthesia and Analgesia. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 20, No 1 (2014) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Running the rat race. W Pearce. Abstract.

  13. Ketamine: old dogs, new tricks | Wilson | Southern African Journal of ...

    African Journals Online (AJOL)

    Southern African Journal of Anaesthesia and Analgesia. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 19, No 1 (2013) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected ...

  14. The use of ketamine in cancer palliation | Smith | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of Anaesthesia and Analgesia. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 13, No 2 (2007) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected ...

  15. Adaptations in primary wing moult of southern African Viduidae and ...

    African Journals Online (AJOL)

    Primary wing moult patterns in southern African brood-parasitic viduines were compared with those of their estrildid hosts. We searched for similarities in the timing and duration of moult within these closely related species potentially arising from their linked breeding biology and geographical distributions. Contrasting ...

  16. Viral dynamics of HIV-1 infection | Martin | Southern African Journal ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 3, No 2 (2002) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Viral dynamics of HIV-1 infection. D Martin ...

  17. Dose scaling for the morbidly obese | Coetzee | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of Anaesthesia and Analgesia. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 20, No 1 (2014) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected ...

  18. You cannot ignore me | Manzvanzvike | SAFERE: Southern African ...

    African Journals Online (AJOL)

    SAFERE: Southern African Feminist Review. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 3, No 1 (1999) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. DOWNLOAD FULL TEXT Open Access ...

  19. Strategies of Water Conservation in Southern African Frogs ...

    African Journals Online (AJOL)

    The three approaches which anurans have adopted in response to water conservation problems have their correlates in bladder size and function. hormonal regulation of water balance and the extent to which water loss can be tolerated. The potential that the southern African amphibian fauna offers for physiological ...

  20. Changes to the scientific and common names of southern African ...

    African Journals Online (AJOL)

    Additions and changes to the scientific and common names of southern African freshwater fishes made since 1993, are recorded and explained. Nineteen new scientific names are listed including five new species, three genus-name changes, three species-name changes and four new records from the area.

  1. EEASA members opinion survey | Irwin | Southern African Journal of ...

    African Journals Online (AJOL)

    Southern African Journal of Environmental Education. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 9 (1988) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. EEASA members opinion survey. Pat Irwin. Abstract.

  2. Starting infants on antiretroviral therapy | Clayden | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 9, No 4 (2008) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected ...

  3. The Status of Herpetology in Southern Africa | Broadley | African ...

    African Journals Online (AJOL)

    The major developments in southern African herpetology during the last decade are reviewed and first consideration is given to the taxonomic work which is essential to provide a sound foundation for subsequent zoogeographical ecological and ethological research. With the passage of time there will be a gradual shift in ...

  4. Dietary iron overload in southern African rural blacks | Friedman ...

    African Journals Online (AJOL)

    A survey conducted in rural southern African black subjects indicated that dietary iron overload remains a major health problem. A full blood count, erythrocyte sedimentation rate, serum concentrations of iron, total iron-binding capacity, ferritin, C-reactive protein (CRP), 1'-glutamyltransferase (GGn and serological screening ...

  5. Oral hygiene care in critically ill patients | Human | Southern African ...

    African Journals Online (AJOL)

    A discussion of the available research evidence to guide oral hygiene care activities includes aspects of timing as well as recommended 'tools'. While some nursing-led research has been published on this topic, there is scope for further investigation into oral hygiene care practices in the critically ill. Southern African ...

  6. HIV and allergy | van Roayen | Southern African Journal of HIV ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 2, No 4 (2001) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. HIV and allergy. C van Roayen, LM Webber. Abstract. No Abstract.

  7. Three species of piscine parasitic copepods from southern African ...

    African Journals Online (AJOL)

    1992-09-04

    Sep 4, 1992 ... tuna, beskryf. Verskeie moriologiese variasies van ander beskrywings word in al drie spesies aangetoon. The three species of piscine parasitic copepods described here represent new and only descriptions from southern. African marine fish. Lepeopthirius nordmanni (Edwards,. 1840) was sampled from ...

  8. Message From the Editor | Myer | Southern African Journal of HIV ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 15, No 3 (2014) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Message From the Editor. L Myer. Abstract.

  9. Letter to the Editor: Polluting the well | Rodseth | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of Anaesthesia and Analgesia. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 23, No 6 (2017) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. Letter to the Editor: Polluting the ...

  10. Southern African Regional Science Initiative (SAFARI 2000): wet season campaigns

    CSIR Research Space (South Africa)

    Otter, LB

    2002-03-01

    Full Text Available The Southern African Regional Science Initiative (SAFARI 2000) involved two wet season and one dry season field campaigns. This paper reports on the wet season campaigns. The first was conducted at five sites along the Kalahari Transect in Zambia...

  11. Non-invasive mechanical ventilation | Giles | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of Critical Care. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 21, No 1 (2005) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should load ...

  12. Salinity ranges of some southern African fish species occurring in ...

    African Journals Online (AJOL)

    The recorded salinity ranges of 96 fish species occurring in southern African estuaries are documented. Factors influen- cing the tolerance of fishes to low and high salinity regimes are discussed, with most species tolerant of low rather than high salinity conditions. This is important since most systems are subject to periodic ...

  13. Mass-Produced, Buffer | Masitera | SAFERE: Southern African ...

    African Journals Online (AJOL)

    SAFERE: Southern African Feminist Review. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 3, No 2 (1999) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register. DOWNLOAD FULL TEXT Open Access DOWNLOAD FULL ...

  14. The status of some southern African nominal species of Cucumaria ...

    African Journals Online (AJOL)

    1986-05-19

    May 19, 1986 ... and the confusion in their taxonomic status discussed. Morphological differences and habitat ... Mediterranean Oenus syraeusanus (Grube) be also classified in the new genus. A key to the three southern. African ... Deichmann's (1948) error in regarding Theel's c. insolens as a growth stage of sykion.

  15. A review of renal protection strategies | Meyer | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of Anaesthesia and Analgesia. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 21, No 2 (2015) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF ...

  16. Population Dynamics of the Giant African River Prawn ...

    African Journals Online (AJOL)

    USER

    Paper 11 of 18. Population Dynamics of the Giant African River Prawn. Macrobrachium vollenhovenii. Herklots 1857 (Crustacea,. Palaemonidae) in the Cross River Estuary, Nigeria. F. M. Nwosu1* and M. Wolfi2. 1 Institute of Oceanography, University of Calabar, P.M.B 1115, Calabar, Nigeria. E-mail: fmnwosu@yahoo.com.

  17. Genetic characterization of native southern African chicken ...

    African Journals Online (AJOL)

    Unknown

    for the genetic conservation of poultry resources (Scherf, 1995). Similar projects have since been undertaken for all the major livestock species (Mason & Crawford, 1993). To date, native South African chicken lines have received very little scientific attention, and research projects have been directed primarily towards ...

  18. Review of Southern African Studies: Submissions

    African Journals Online (AJOL)

    Privacy Statement. The names and email addresses entered in this journal site will be used exclusively for the stated purposes of this journal and will not be made available for any other purpose or to any other party. ISSN: 1024-4190. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians ...

  19. The Southern African Development Community trade legal

    African Journals Online (AJOL)

    UNISA

    List of abbreviations and acronyms. ACP – African, Caribbean and Pacific Group of States. BLNS- Botswana, Lesotho, Namibia and Swaziland. CRTA- Committee on Regional Trade Agreements. CTG- Council on Trade in Goods. EPA- Economic Partnership Agreements. EU- European Union. FTA- Free Trade Area.

  20. SAFERE: Southern African Feminist Review: Editorial Policies

    African Journals Online (AJOL)

    SAFERE provides women with a writing platform which is feminist in content and orientation, as well as facilitating for African women to express their ideas and ... The Journal is one of barely a handful of feminist journals coming out of Africa, and through careful editing and the collection of high quality written work, it has ...

  1. Archives: Southern African Journal of Environmental Education

    African Journals Online (AJOL)

    5959. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES... for Researchers ...

  2. Southern African Development Research Network | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Members of the Southern Africa Development Community (SADC) are struggling to craft policies for fruitful integration into the global economy and inclusive growth. While some donor initiatives have been successful in meeting short-term policy needs, they are not sustainable solutions to a weak research and policy ...

  3. Genetic characterization of native southern African chicken ...

    African Journals Online (AJOL)

    This study presents the first results on the evaluation and selection of polymorphic microsatellite markers for the genetic characterization of native chicken populations in southern Africa. Blood samples for DNA extraction were obtained from five chicken lines from South Africa (Koekoek, New Hampshire, Naked-Neck, ...

  4. Marketing University Education: The Southern African Experience.

    Science.gov (United States)

    Maringe, Felix; Foskett, Nick

    2002-01-01

    Examined the perceptions of university marketers in southern Africa. Found a varying awareness of the significance of marketing, with more mature institutions exhibiting more developed marketing orientations. Strategies ranged from marketing as public relations to marketing as sales, with universities in South Africa the only ones demonstrating a…

  5. Dispersal of river sediment in the Southern California Bight

    Science.gov (United States)

    Warrick, J.A.; Farnsworth, K.L.

    2009-01-01

    The rivers of Southern California deliver episodic pulses of water, sediment, nutrients, and pollutants to the region's coastal waters. Although river-sediment dispersal is observed in positively buoyant (hypopycnal) turbid plumes extending tens of kilometers from river mouths, very little of the river sediment is found in these plumes. Rather, river sediment settles quickly from hypopycnal plumes to the seabed, where transport is controlled by bottom-boundary layer processes, presumably including fluid-mud (hyperpycnal) gravity currents. Here we investigate the geographical patterns of river-sediment dispersal processes by examining suspended-sediment concentrations and loads and the continental shelf morphology offshore river mouths. Throughout Southern California, river sediment is discharged at concentrations adequately high to induce enhanced sediment settling, including negative buoyancy. The rivers draining the Western Transverse Range produce suspended-sediment concentrations that are orders of magnitude greater than those in the urbanized region and Peninsular Range to the south, largely due to differences in sediment yield. The majority of sediment discharge from the Santa Clara River and Calleguas Creek occurs above the theoretical negative buoyancy concentration (>40 g/l). These rivers also produce event sediment loading as great as the Eel River, where fluid-mud gravity currents are observed. The continental shelf of Southern California has variable morphology, which influences the ability to transport via gravity currents. Over half of the rivers examined are adjacent to shelf slopes greater than 0.01, which are adequately steep to sustain auto-suspending gravity currents across the shelf, and have little (fluid-mud gravity currents could transport across these shelves, albeit slowly (??10 cm/s) and only with adequate wave-generated shear stress and sediment loading. Calleguas Creek is unique in that it discharges directly into a steepsloped canyon

  6. Water quality assessment of the Sinos River, Southern Brazil

    Directory of Open Access Journals (Sweden)

    KK. Blume

    Full Text Available The Sinos River basin is located Northeast of the state of Rio Grande do Sul (29º 20' to 30º 10' S and 50º 15' to 51º20'W, Southern Brazil, covering two geomorphologic provinces: the Southern plateau and central depression. It is part of the Guaíba basin and has an area of approximately 800 km², encompassing 32 municipalities. The objective of this study was to monitor water quality in the Sinos River, the largest river in this basin. Water samples were collected at four selected sites in the Sinos River, and the following parameters were analysed: pH, dissolved oxygen, biochemical oxygen demand (BOD5, turbidity, fecal coliforms, total dissolved solids, temperature, nitrate, nitrite, phosphorous, chromium, lead, aluminum, zinc, iron, and copper. The results were analysed based on Resolution No. 357/2005 of the Brazilian National Environmental Council (CONAMA regarding regulatory limits for residues in water. A second analysis was performed based on a water quality index (WQI used by the Sinos River Basin Management Committee (COMITESINOS. Poor water quality in the Sinos River presents a worrying scenario for the region, since this river is the main source of water supply for the urban core. Health conditions found in the Sinos River, mainly in its lower reaches, are worrying and a strong indicator of human activities on the basin.

  7. Zooplankton from can Giuoc River in Southern Vietnam

    Directory of Open Access Journals (Sweden)

    Duc Pham Anh

    2016-12-01

    Full Text Available In this study, the variables of zooplankton and water quality were investigated in the Can Giuoc River, Southern Vietnam. Zooplankton was monitored in April and September 2015 at 5 sampling sites in the river. Some basic water quality parameters were also tested, including pH, total suspended solid (TSS, dissolved oxygen (DO, biological oxygen demand (BOD5, inorganic nitrogen (NH4+, dissolved phosphorus (PO43−, and coliform. The zooplankton biodiversity indices were applied for the water quality assessment.

  8. Different cranial ontogeny in Europeans and Southern Africans.

    Directory of Open Access Journals (Sweden)

    Marina L Sardi

    Full Text Available Modern human populations differ in developmental processes and in several phenotypic traits. However, the link between ontogenetic variation and human diversification has not been frequently addressed. Here, we analysed craniofacial ontogenies by means of geometric-morphometrics of Europeans and Southern Africans, according to dental and chronological ages. Results suggest that different adult cranial morphologies between Southern Africans and Europeans arise by a combination of processes that involve traits modified during the prenatal life and others that diverge during early postnatal ontogeny. Main craniofacial changes indicate that Europeans differ from Southern Africans by increasing facial developmental rates and extending the attainment of adult size and shape. Since other studies have suggested that native subsaharan populations attain adulthood earlier than Europeans, it is probable that facial ontogeny is linked with other developmental mechanisms that control the timing of maturation in other variables. Southern Africans appear as retaining young features in adulthood. Facial ontogeny in Europeans produces taller and narrower noses, which seems as an adaptation to colder environments. The lack of these morphological traits in Neanderthals, who lived in cold environments, seems a paradox, but it is probably the consequence of a warm-adapted faces together with precocious maturation. When modern Homo sapiens migrated into Asia and Europe, colder environments might establish pressures that constrained facial growth and development in order to depart from the warm-adapted morphology. Our results provide some answers about how cranial growth and development occur in two human populations and when developmental shifts take place providing a better adaptation to environmental constraints.

  9. Institutional development paths in seaports: the southern African case

    OpenAIRE

    Fraser, D; Notteboom, T

    2015-01-01

    In the last three decades, transport economists and geographers have published an array of studies on port institutions and governance. Many of these publications emphasize the role of institutions in enabling or inhibiting port efficiencies, port competition (inter and intra) and the development of a port's resources and capabilities. Political instabilities and their consequential economic lags have to some extent misaligned the pace of institutional reforms in Southern African ports compar...

  10. Towards migration research networking in Eastern-Southern African subregions.

    Science.gov (United States)

    Oucho, J O

    1993-01-01

    This article reports efforts made by a small group of Eastern-Southern African (ESA) subregion scholars to adopt a systematic approach to establishing a regional network Migration Network in Eastern and Southern Africa (MINESA). The approach involved: 1) holding a conference at which symptomatic types of internal and international migration would be discussed; 2) publication of the conference proceedings; and 3) establishment of MINESA as a network of policy-oriented research in the two subregions. The first stage has been accomplished, the second is nearly complete, and the third has yet to be undertaken. During the African Population Conference organized by the International Union for Scientific Study of Population in Dakar, Senegal, on 5-9 November 1988, a small group agreed on a timetable to establish MINESA. At the ESA conference, papers were presented on ESA issues; internal migration processes and mechanism; refugee movements and their implications for countries; the effects on the economies of Southern African states, of emigration to the Republic of South Africa (RSA). In a keynote address, Adepoju surveyed migration and development in Western-Central (Middle) Africa and Eastern-Southern Africa, which included colonial and post-colonial historical epochs, internal and international migration, and labor and refugee movements. A paper on Kenya by Oucho discussed the implications for rural-urban balance of internal migration based on 1969 and 1979 censuses. Rural-urban migration from the traditional economy to Nairobi and Mombasa in particular has created an unacceptable rural-urban imbalance, adversely affecting rural development. Eastern and Southern Africa has seen massive and wide spatial dispersal of refugees (victims of wars, drought, and famine). Two papers were presented on Tanzania and one on Uganda. The final set of papers addressed the effects of labor migration to the RSA on Swaziland and Lesotho.

  11. Ecological Status of Owan River, Southern Nigeria using Aquatic ...

    African Journals Online (AJOL)

    Aquatic insects are among the most directly affected and vulnerable organisms with respect to surface water pollution and used as bioindicators of water quality. The composition, distribution and diversity of aquatic insects in Owan River, southern Nigeria were assessed and influence of different physico-chemical factors ...

  12. hydromedusae off the orange river mouth, southern africa

    African Journals Online (AJOL)

    A total of 242 zooplankton samples from the upper 100 m of the water column was collected discontinuously from March 1997 to January 1999 off the Orange River mouth on the west coast of southern Africa. Six species of hydromedusae were recovered at generally low abundance, of which Euphysa aurata, Leuckartia ...

  13. SAFARI 2000 Estimated BVOC Emissions for Southern African Land Cover Types

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Improved vegetation distribution and emission data for Africa south of the equator were developed for the Southern African Regional Science Initiative...

  14. The recreational value of river inflows into South African estuaries ...

    African Journals Online (AJOL)

    The contingent valuation method was used to estimate the value of recreational benefits that would result at 40 South African estuaries if water-inflow reductions were averted. The studies were undertaken between 2000 and 2007. All the estuaries selected were known to be vulnerable to changes in river inflows.

  15. Southern African Power Pool: Planning and Prospects for Renewable Energy

    Energy Technology Data Exchange (ETDEWEB)

    Miketa, Asami [IRENA, Bonn (Germany); Merven, Bruno [Energy Research Centre, Univ. of Cape Town (South Africa)

    2013-06-25

    With the energy systems of many African countries dominated by fossil-fuel sources that are vulnerable to global price volatility, regional and intra-continental power systems with high shares of renewable energy can provide least-cost option to support continued economic growth and address the continent’s acute energy access problem. Unlocking Africa’s huge renewable energy potential could help to take many people out of poverty, while ensuring the uptake of sustainable technologies for the continent’s long-term development. The report examines the ''renewable scenario'' based on a modelling tool developed by IRENA and tested in cooperation with the South African National Energy Development Institute (SANEDI) and the Southern African Development Community (SADC). Initial results from the System Planning and Test (SPLAT) model show that the share of renewable technologies in Southern Africa could increase from the current 10% to as much as 46% in 2030, with 20% of decentralised capacity coming from renewable sources and nearly 80% of the envisaged capacity additions between 2010 and 2030 being provided by renewable energy technologies. Deployment and export of hydropower from the Democratic Republic of Congo’s Inga hydropower project to the SADC region would significantly reduce average electricity generation costs. Analysis using SPLAT – along with a similar model developed for West Africa – can provide valuable input for regional dialogue and energy projects such as the East and Southern Africa Clean Energy Corridor and the Programme for Infrastructure and Development in Africa (PIDA). IRENA, together with partner organisations, has started plans to set up capacity building and development support for energy system modelling and planning for greater integration of renewables in Africa. IRENA is also completing a similar model and study for East Africa and intends to extend this work to Central and North Africa.

  16. A Pan-African thermal event in southern India

    Science.gov (United States)

    Miller, Jonathan S.; Santosh, M.; Pressley, Rachel A.; Clements, Alina S.; Rogers, John J. W.

    UPb zircon data from five igneous suites confirm previous studies that demonstrated widespread Pan-African magmatism in the Granulite Terrain of southern India. Ages determined here are ˜560 Ma for the Peralimala Granite and ˜555 Ma for the Kalpatta Granite, both north of the Palghat-Cauvery lineament, and ˜585 Ma for a charnockite in the Cardamom massif south of the lineament. Zircon from a pegmatite in the Kerala khondalite belt at Melankode yields an age of 512 Ma. Resetting of zircons in the 2500-Ma Arsikere Granite of the western Dharwar craton probably occurred at ˜450 Ma. These ages and the concentration of Pan-African granitic magmatism around the Indian portion of a broad region of granulite-facies metamorphism in East Gondwana demostrates generation of a restricted area of high temperature either above a rising plume or a zone of rifting. Mantle-derived fluids continued to move upward through the crust of southern India for at least 100 m.y. after the peak of magmatism, and the entire region was still cooling at 400 Ma.

  17. Genotoxic potential and physicochemical parameters of Sinos River, southern Brazil.

    Science.gov (United States)

    Scalon, Madalena C S; Rechenmacher, Ciliana; Siebel, Anna Maria; Kayser, Michele L; Rodrigues, Manoela T; Maluf, Sharbel W; Rodrigues, Marco Antonio S; Silva, Luciano Basso da

    2013-01-01

    The present study aimed to evaluate the physicochemical parameters and the genotoxic potential of water samples collected in the upper, middle, and lower courses of the Sinos River, southern Brazil. The comet assay was performed in the peripheral blood of fish Hyphessobrycon luetkenii exposed under laboratory conditions to water samples collected in summer and winter in three sampling sites of Sinos River. Water quality analysis demonstrated values above those described in Brazilian legislation in Parobé and Sapucaia do Sul sites, located in the middle and in the lower courses of the Sinos River, respectively. The Caraá site, located in the upper river reach, presented all the physicochemical parameters in accordance with the allowed limits in both sampling periods. Comet assay in fish revealed genotoxicity in water samples collected in the middle course site in summer and in the three sites in winter when compared to control group. Thus, the physicochemical parameters indicated that the water quality of the upper course complies with the limits set by the national guidelines, and the ecotoxicological assessment, however, indicated the presence of genotoxic agents. The present study highlights the importance of combining water physicochemical analysis and bioassays to river monitoring.

  18. The recreational value of river inflows into South African estuaries

    African Journals Online (AJOL)

    From the elicited responses median estuary user willingness to pay bids were predicted using. Tobit and OLS ... median values of river inflow into estuaries was calculated to be 3.4 c/m3 (South African cents, ZAR) and standard devia- tion 3.84 c/m3. .... forestry expansion and by-products, and has taken the form of reduced ...

  19. Assessment of intermediate fine sediment storage in a braided river reach (southern French Prealps)

    OpenAIRE

    Navratil, Oldrich; Legout, C.; Gateuille, D.; Esteves, Michel; Liebault, F.

    2010-01-01

    This paper presents a field investigation on river channel storage of fine sediments in an unglaciated braided river, the Bes River, located in a mountainous region in the southern French Prealps. Braided rivers transport a very large quantity of bedload and suspended sediment load because they are generally located in the vicinity of highly erosive hillslopes. Consequently, these rivers play an important role because they supply and control the sediment load of the entire downstream fluvial ...

  20. SAFARI 2000 Estimated BVOC Emissions for Southern African Land Cover Types

    Data.gov (United States)

    National Aeronautics and Space Administration — Improved vegetation distribution and emission data for Africa south of the equator were developed for the Southern African Regional Science Initiative (SAFARI 2000)...

  1. Aspects of potential climate change impacts on ports and maritime operations around the Southern African coast

    CSIR Research Space (South Africa)

    Rossouw, Marius

    2009-02-01

    Full Text Available to become available, and the resulting somewhat speculative discussions and predictions presented here are uncertain. Some important potential consequences of global warming on the southern African coast are highlighted, and there is presently a clear...

  2. Epidemiology of HIV/AIDS in South Africa | Allen | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 1, No 1 (2000) >. Log in or Register to get access to full text downloads.

  3. Integrated mapping of groundwater drought risk in the Southern African Development Community (SADC) region

    CSIR Research Space (South Africa)

    Villholth, KG

    2013-06-01

    Full Text Available and human vulnerability associated with diminished groundwater availability and access during drought. An integrated management support tool, GRiMMS, is presented, for the mapping and assessment of relative groundwater drought risk in the Southern African...

  4. Increasing summer river discharge in urbanized watersheds in southern California

    Science.gov (United States)

    Townsend-Small, A.; Nash, D.; Finan, K.; Liu, H.; Thomas, B.; Li, Z.; Wu, Q.

    2012-12-01

    Urban areas alter hydrologic flowpaths through increased impermeable surface area, which leads to a greater proportion of runoff versus infiltration during rain events. In semi-arid regions, however, there may be an additional impact of urbanization on stream flow rates via increased dry-season runoff due to landscaping irrigation and sewage treatment plant effluent. In this presentation, we will show that summer river discharge is increasing in urban and suburban southern California, USA, despite a lack of summer precipitation. The data were collected online from the USGS stream gauge network. The Los Angeles area megacity relies heavily on imported water from northern and western parts of California and the other parts of the southwestern USA. This water transportation network is a large drain on water resources in source regions and is one of the largest electricity consumers in the state. A close analysis of the streamflow data along with satellite-derived land cover data indicate that summer river discharge is low to nonexistent in most undeveloped watersheds, with no temporal trend, while urban and suburban river discharge has been increasing throughout the past 50 or 60 years. This has important implications for water policy in California, as water resources are expected to become more scarce with decreasing snowpack in the Sierra Nevada mountains. There are also potential health impacts for this research, as urban runoff can cause high bacterial counts and beach closures in this region. Potential causes for increasing summer river discharge will be discussed as well as suggestions for remediation and conservation.

  5. Southern African Journal of Critical Care - Vol 26, No 2 (2010)

    African Journals Online (AJOL)

    Southern African Journal of Critical Care. ... The experiences of nurses in providing psychosocial support to families of critically ill trauma patients in intensive care units ... Psychological sequelae following ICU admission at a level 1 academic South African hospital · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  6. End-of-life care in intensive care units | Langley | Southern African ...

    African Journals Online (AJOL)

    No Abstract Southern African Journal of Critical Care Vol. 22 (2) 2006: pp. 58-65. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

  7. SWOT Analysis of Extension Systems in Southern African Countries

    Directory of Open Access Journals (Sweden)

    Oladimeji Idowu Oladele

    2011-11-01

    Full Text Available This paper examined the strengths, weaknesses, opportunities and threats to extension systems in selected southern African countries of Malawi, Zambia, Swaziland, Mozambique, Lesotho and Botswana. This is predicated on the need for improved performance and reinvigoration of extension system for better services. Some of the strengths are development works to improve rural areas, extensive grassroots coverage, and use of committees for research and extension linkages, involvement of NGOs and private sector, and effective setting of extension administration units. On the other hand opportunities that can be explored are donor will fund well designed programme, expansion in the use of ICT, high involvement of farmers in extension planning, and potential for effective programme implementation. The threats to the extension systems are attempts to privatize extension services, weak feedback to research, and donor fatigue. The paper recommends that extension administrators, and policy makers should pay proper attention to the strengths, weaknesses, opportunities and threats to extension systems with a view of making extension services truly more responsive to local concerns and policy.

  8. 21st Century African Philosophy of Adult and Human Resource Education in Southern Africa

    Science.gov (United States)

    Mutamba, Charlene

    2012-01-01

    This paper will attempt to define a philosophy of adult education for the purpose of workforce development in Southern Africa. The different influences such as Ubuntu and communalism, indigenous education, diversity western philosophy, globalization and technology are explored in the context of the Southern African region.

  9. Does South Africa Still Need the Southern African Customs Union in ...

    African Journals Online (AJOL)

    ... Customs Union in relation to the Southern African Development Community in the advancement of its long-term strategic interests in Southern Africa and Africa. By consolidating its regional and continental status and seeking to be an international power, a major force within the Group of 20 countries and Brazil, Russia, ...

  10. African Instituted Churches in Southern Africa: Paragons of Regional ...

    African Journals Online (AJOL)

    sulaiman.adebowale

    2006-05-23

    May 23, 2006 ... Lack of leadership opportunities, personal ambitions, theo- logical controversies ..... AICs proclaimed the gospel of self-reliance and utilisation of African. 7. ... bering the sacrificial death of Jesus, they solidify a common African.

  11. A multibiomarker approach in rats to assess the impact of pollution on Sinos River, Southern Brazil

    National Research Council Canada - National Science Library

    Rechenmacher, C; Siebel, A M; Goldoni, A; Klauck, C R; Sartori, T; Rodrigues, M T; Rodrigues, M A S; Gehlen, G; Ardenghi, P G; Silva, L B

    2010-01-01

    ... response in the Sinos River, southern Brazil. Wistar rats were studied using three biomarkers combined with physical, chemical and microbiological analysis to assess the effects of pollution at four sampling sites...

  12. Ohio River backwater flood-inundation maps for the Saline and Wabash Rivers in southern Illinois

    Science.gov (United States)

    Murphy, Elizabeth A.; Sharpe, Jennifer B.; Soong, David T.

    2012-01-01

    Digital flood-inundation maps for the Saline and Wabash Rivers referenced to elevations on the Ohio River in southern Illinois were created by the U.S. Geological Survey (USGS). The inundation maps, accessible through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent of flooding corresponding to selected water levels (gage heights) at the USGS streamgage at Ohio River at Old Shawneetown, Illinois-Kentucky (station number 03381700). Current gage height and flow conditions at this USGS streamgage may be obtained on the Internet at http://waterdata.usgs.gov/usa/nwis/uv?03381700. In addition, this streamgage is incorporated into the Advanced Hydrologic Prediction Service (AHPS) flood warning system (http://water.weather.gov/ahps/) by the National Weather Service (NWS). The NWS forecasts flood hydrographs at many places that are often co-located at USGS streamgages. That NWS forecasted peak-stage information, also shown on the Ohio River at Old Shawneetown inundation Web site, may be used in conjunction with the maps developed in this study to show predicted areas of flood inundation. In this study, eight water-surface elevations were mapped at 5-foot (ft) intervals referenced to the streamgage datum ranging from just above the NWS Action Stage (31 ft) to above the maximum historical gage height (66 ft). The elevations of the water surfaces were compared to a Digital Elevation Model (DEM) by using a Geographic Information System (GIS) in order to delineate the area flooded at each water level. These maps, along with information on the Internet regarding current gage heights from USGS streamgages and forecasted stream stages from the NWS, provide emergency management personnel and residents with information that is critical for flood response activities such as evacuations and road closures, as well as for post-flood recovery efforts.

  13. Southern African Journal of Anaesthesia and Analgesia - Vol 21, No ...

    African Journals Online (AJOL)

    Guest Editorial: South African guidelines for the treatment of cancer pain: South African Cancer Pain Guidelines Working Group · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL ... regional techniques? Evidence from large studies with big data · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  14. Strategic culture of the Southern African Development Community ...

    African Journals Online (AJOL)

    This SADC Brigade is tied in closely to both the security architecture of the African Standby Force (ASF) of the African Union (AU) and the SADC Mutual Defence Pact. In the recent past (1998), military interventions by SADC members into Lesotho and the Democratic Republic of the Congo (DR Congo) caused the SADC to ...

  15. Water quality studies on two irrigation-associated rivers in southern ...

    African Journals Online (AJOL)

    The water quality of two rivers, Ayensu and Okyi-Amisa, associated with irrigation in southern Ghana were assessed in a bid to determine impacts downstream of the irrigated farmlands. Both have man-made reservoirs on their tributaries which flow under gravity into farmlands before entering the main river. A variety of ...

  16. Diversity as a common research priority for Nordic and Southern African Universities

    DEFF Research Database (Denmark)

    Petersen, Karen Bjerg

    This paper sets out to consider concepts of diversity as means to discuss and address the increasing diversity of modern societies and to reflect the development of research priorities for universities in Nordic and Southern African countries. Based on reconceptualisations of theoretical concepts...... countries like e.g. Denmark have responded differently to diversification during the past decades. Based on this, challenges in deal-ing with diversity as a common research priority for Nordic and African universities will be shortly addressed....

  17. Reconsidering the origins of the Southern African regionalism thirty years later: towards a constructivist approach to the origins of SADC

    Directory of Open Access Journals (Sweden)

    José Abel Moma

    2012-01-01

    Full Text Available The creation of SADCC has generated a debate over the real origins of the southern African model of regionalism. This paper develops the idea that the origins of SADC are both internal and external. Thus, southern African regionalism is understood as a constructivist articulation of internal and external inputs, which determined the creation of SADCC and its transformation into SADC.

  18. Children with Kaposi Sarcoma in Two Southern African Hospitals: Clinical Presentation, Management, and Outcome

    OpenAIRE

    de Bruin, G.P.; Stefan, D. C.

    2013-01-01

    Introduction. In 2010 more than 3 million children with human immunodeficiency virus (HIV) were living in Sub-Saharan Africa. The AIDS epidemic has contributed to an abrupt increase of the frequency of Kaposi sarcoma (KS), especially in Southern Africa. There is a need to describe the clinical features of this disease, its management, and its outcome in HIV positive children in Southern Africa. The aim of the study is to describe two different populations with HIV and KS from two African hosp...

  19. Timing of the Southern African Plateau uplift : a couple landforms-margin study of Southern Namibia

    Science.gov (United States)

    Guillocheau, François; Dauteuil, Olivier; Baby, Guillaume; Pickford, Martin; Senut, Brigitte

    2014-05-01

    The timing of the uplift of the Southern African (or Kalahari) Plateau is debated, with four scenarios of uplift: (1) at time of rifting (Early Cretaceous), (2) during Late Cretaceous, (3) around the Eocene-Oligocene boundary and (4) during Pliocene times. This knowledge is of primary importance for a better understanding of the mantle processes at the origin of this very long wavelength structure. To answer this question, we studied the key area of the northern Orange Margin (sequence stratigraphic analysis of seismic lines and wells), offshore of the Sperrgebiet. This study is coupled with an analysis of the landforms dated with associated sediments and volcanics. (1) The first uplift of the Plateau was during Late Cretaceous times, with a first increase of siliciclastic sediments supply during Late Cenomanian (95-90 Ma) in response to the beginning of the uplift along the Indian Ocean side that propagates eastward around the Campanian (85-70 Ma). (2) Because of the humid climatic conditions prevailing since Santonian (85 Ma), most of the relief of this first plateau is removed by erosion. At the end of the planation of this topography, chemical erosion is dominant with the growth of thick lateritic profiles (55?-45 Ma). (3) A second uplift of the Plateau occurred during Late Eocene-Early Oligocene (30-40 Ma - paroxysm) and Miocene with the incision of at least three generations of pediments that shape the present-day ""Great"" Escarpment. (4) This "old" Oligocene relief is probably preserved because of the decrease of the erosion due to the climate aridification, starting at Middle Miocene times (around 15 Ma).

  20. Abundance and Distribution of African Fish Eagles along Major Rivers in Gonarezhou National Park, Zimbabwe

    NARCIS (Netherlands)

    Zisadza-Gandiwa, P.; Chiganze, S.; Chirombe, P.; Mashapa, C.; Muboko, N.; Gandiwa, E.

    2013-01-01

    African fish eagles (Haliaeetus vocifer) are important birds of prey and indicator of ecosystem integrity in aquatic environments. We assessed the population abundance and spatial distribution of African fish eagles along three major rivers in Gonarezhou National Park, Zimbabwe. Data were collected

  1. Southern African Business Review - Vol 14, No 1 (2010)

    African Journals Online (AJOL)

    Approaches taken by South African advertisers to select and appoint advertising agencies · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. M Jansen van Rensburg, P Venter, JW Strydom ...

  2. Southern African Business Review - Vol 13, No 2 (2009)

    African Journals Online (AJOL)

    The availability and use of competitive and business intelligence in South African business organisations · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. P Venter, D Tustin ...

  3. Southern African Development Community (SADC): Towards Economic Integration

    National Research Council Canada - National Science Library

    Mokgware, Pius

    2002-01-01

    Southern Africa is a region richly endowed with human, natural, agricultural and mineral resources but the majority of people live in extreme poverty, and declining life expectancy and limited access...

  4. Notes on the activity patterns of 12 species of southern African ...

    African Journals Online (AJOL)

    The circadian activity patterns of 12 species of southern African rodents are described under controlled laboratory conditions. Activity was measured in a newly described apparatus, in which rodents, traver- sing infra-red light beams placed across several arenas and nest· boxes, activated a microprocessor which quantified, ...

  5. Ladies Are Seen, Not Heard: Language Socialization in a Southern, African American Cosmetology School.

    Science.gov (United States)

    Jacobs-Huey, Lanita

    2003-01-01

    Examined classroom discourse at a southern cosmetology school, noting African American students' language socialization. Highlighted freshmen's and seniors' engagement with formal/textbook scripts about proper communication, analyzing how teachers and students made sense of official metacommunicative scripts about proper salon communication.…

  6. Historical analysis of the Journal of the Southern African Society of ...

    African Journals Online (AJOL)

    For many years the Journal published by the Southern African Society of Aquatic Scientists has aimed to provide a forum for the publication of research results, observations, comment, theories, hypotheses and other information on natural waters in and around Africa south of the Sahara. The objective has been to promote ...

  7. Southern African Journal of HIV Medicine - Vol 5, No 3 (2004)

    African Journals Online (AJOL)

    ... therapy among HIVinfected Southern Africans: time to change policy? EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Gavin J Churchyard, Katherine Fielding, Salome Charalambous, John H Day, Elizabeth L Corbett, Richard J Hayes, Richard E Chaisson, Kevin M ...

  8. HIV/TB: When is it safe to start HAART? | Wood | Southern African ...

    African Journals Online (AJOL)

    Southern African Journal of HIV Medicine. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 9, No 4 (2008) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected ...

  9. Electricity supply and demand scenarios for the Southern African power pool

    CSIR Research Space (South Africa)

    Spalding-Fecher, R

    2017-02-01

    Full Text Available The study presents long-term electricity supply and demand scenarios for the twelve countries in the Southern African Power Pool, based on detailed bottom-up demand analysis for all countries and a set of internally consistent development scenarios...

  10. Water quality of the Modder River, South Africa | Koning | African ...

    African Journals Online (AJOL)

    The Modder River is a relatively small river in the central region of the Free State Province, South Africa and has a mean annual runoff of 184 x 106m3. Botshabelo is a city, which has developed in the catchment area of the river, and its sewage outflows are discharged into the Klein Modder, a tributary of the Modder River.

  11. Mitigating the UHI: Considerations for Southern African cities

    CSIR Research Space (South Africa)

    Naidoo, Sasha

    2016-12-01

    Full Text Available . The relevance of the UHI in the context of South African cities was discussed in terms of limited UHI studies and considerations for cooling strategies in cities, as well as the appropriateness of these strategies in terms of planned long-term development goals...

  12. African Instituted Churches in Southern Africa: Paragons of Regional ...

    African Journals Online (AJOL)

    sulaiman.adebowale

    2006-05-23

    May 23, 2006 ... pose, Africa shall finally shrug off the “Dark Continent” image and experience remarkable .... response to oppressive legislation that sought to protect white interests during the colonial period. Masowe encouraged ... This South African influence can also be detected in the spread of wom-. 7.Chitando2.pmd.

  13. Southern African Business Review - Vol 15, No 3 (2011)

    African Journals Online (AJOL)

    An investigation into youth entrepreneurship in selected South African secondary schools: An exploratory study · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT ... The relation between career anchors, emotional intelligence and employability satisfaction among workers in the service industry · EMAIL FREE FULL TEXT ...

  14. 1 St Southern African Students Psychology Conference, Gaborone ...

    African Journals Online (AJOL)

    African Safety Promotion: A Journal of Injury and Violence Prevention. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 7, No 2 (2009) >. Log in or Register to get access to full text downloads.

  15. Southern African Business Review - Vol 18, No 3 (2014)

    African Journals Online (AJOL)

    Senior executives' perspectives of integrated reporting regulatory regimes as a mechanism for advancing sustainability in South African listed companies · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. M Steyn, 142-174 ...

  16. Identity and distribution of southern African sciaenid fish species of ...

    African Journals Online (AJOL)

    U. canariensis is distributed along the South Africa eastern seaboard from Cape Point to Sodwana Bay and U. robinsoni is known from False Bay to Madagascar and Oman. African Umbrina taxonomy has, however, been hindered by geographic samples that were either too few or consisted of specimens of disparate length ...

  17. The Status of Herpetology in Southern Africa | Broadley | African ...

    African Journals Online (AJOL)

    African Zoology. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 11, No 2 (1976) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should load here if your ...

  18. Sen Virus and Hepatocellular Carcinoma in Southern African Blacks ...

    African Journals Online (AJOL)

    SEN virus (SENV), or its variants (SENV-D and SENV-H), have been detected in the serum of patients with hepatocellular carcinoma (HCC), acute or chronic benign hepatic diseases, and healthy individuals in a number of countries. No information has hitherto been available in sub-Saharan African populations.

  19. Southern African Business Review - Vol 19, No 1 (2015)

    African Journals Online (AJOL)

    Online servicescape dimensions as predictors of website trust in the South African domestic airline industry · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. SW Kühn, H Spies, DJ Petzer, 44-71 ...

  20. Southern African Business Review - Vol 16, No 2 (2012)

    African Journals Online (AJOL)

    The importance of choice attributes and the positions of the airlines within the South African domestic passenger airline industry as perceived by passengers at Durban International Airport · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. B Campbell, D Vigar-Ellis ...

  1. Editorial | Thomson | Southern African Journal of Critical Care

    African Journals Online (AJOL)

    Organ donation in South Africa – a call to action. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and ...

  2. New data on southern African Achatinidae (Mollusca, Gastropoda Pulmonata)

    NARCIS (Netherlands)

    Bruggen, van A.C.

    1972-01-01

    Increasing knowledge of the genital anatomy of the species of the African land snail family Achatinidae has greatly improved our understanding of the delimitation of the species and the intricate interrelationships of the various taxa (Mead, 1950). The genitalia of many achatinids are still unknown

  3. Southern African Business Review - Vol 16, No 1 (2012)

    African Journals Online (AJOL)

    Burnout and work engagement of South African blue-collar workers: The development of a new scale · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. L Brand-Labuschagne, K Mostert, S Rothmann Jnr, JC Rothmann, 58-93 ...

  4. The great neglected outdoor classroom! | Opie | Southern African ...

    African Journals Online (AJOL)

    Creative Commons License This work is licensed under a Creative Commons Attribution 3.0 License. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES.

  5. Enjoying the natural environmental in Natal | Gear | Southern African ...

    African Journals Online (AJOL)

    This work is licensed under a Creative Commons Attribution 3.0 License. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES... for Researchers · for ...

  6. El Niño Southern Oscillation Influences River Bank Erosion on the Lower Mekong River

    Science.gov (United States)

    Darby, S. E.; Trieu, H. Q.; Carling, P. A.

    2009-12-01

    . However, both simulated time series exhibit quasi-periodic oscillations about these means. The Mekong’s flow regime is controlled by variations in meltwater regime, the intensity of the SE Asian monsoon, and the frequency and intensity of tropical cyclones that penetrate inland from the South China Sea. Since melt contributes only to (non-erosive) base flows, variability in glacier and snow melt contributions from Himalayan source areas are unlikely to significantly impact inter-annual variations in river bank erosion. However, inter-annual variability in the SE Asian monsoon and tropical cyclone dynamics may both be related, albeit in a complex manner, to the El Niño Southern Oscillation (ENSO). Cross-wavelet transform and wavelet coherence analyses indicate statistically significant (at 95% limit) coherence between ENSO and simulated river bank erosion, but at both sites only since about 1980. During this recent period the ENSO and fluvial erosion time series are in anti-phase; that is ENSO cold phases are associated with enhanced rates of river bank erosion. This is as expected, since ENSO cold phases are associated with earlier onset and enhanced intensity of the monsoon, while the number of intense tropical storm systems making landfall over Vietnam and moving across the Lower Mekong Basin is also higher.

  7. THE ORIGINS OF THE SOUTHERN AFRICAN MAMMAL FAUNA ...

    African Journals Online (AJOL)

    ... the eastern escarpment to the southern Cape Province". Moreau (1952) assembles and discusses evidence for Tertiary and Quaternary climatic changes in Africa, pointing out amongst other things that during the early Tertiary Kalahari con-. ·Now Zoology Department, University of Pretoria. Zo%gica A/ricana 1 (1): 87-93.

  8. Curculionoidea (Coleoptera) from southern Turkey | Avgın | African ...

    African Journals Online (AJOL)

    A checklist of Curculionoidea is given from southern Turkey (Adana, Osmaniye and Hatay provinces). The known localities and ecological notes on each of them were reported based on literature records and on recently collected material. Lixus farinifer Reitter is newly recorded from Turkey, and 35 species (2 Rhynchitidae, ...

  9. Inversion structures in Northern Sotho | Zerbian | Southern African ...

    African Journals Online (AJOL)

    Inversion structures, in which the logical subject appears in postverbal position, are a wide-spread phenomenon among Bantu languages. The paper presents an overview of inversion structures in Bantu languages and describes in detail the inversion constructions in the Southern Bantu language Northern Sotho. It argues ...

  10. Dynamical seasonal prediction of Southern African summer precipitation

    CSIR Research Space (South Africa)

    Yuan, C

    2014-01-01

    Full Text Available ) provides the major source of predictability, but the relationship with ENSO is too strong in the model. The Benguela Niño, the basin mode in the tropical Indian Ocean, the subtropical dipole modes in the South Atlantic and the southern Indian Oceans...

  11. extra-territorial african police and soldiers in southern rhodesia

    African Journals Online (AJOL)

    Abel

    territorial recruits were phased out in ... minority, black security force personnel were a constant factor in the history of. Southern Rhodesia. ... of the colony's defence, they were each issued with a Martini-Henry rifle and five rounds of ammunition.10 ...

  12. Tracing the origins of the Southern African building regulations, with ...

    African Journals Online (AJOL)

    This paper uses contemporary definitions of building regulations and building standards to establish the first performance standard (and the source of building regulations) for Southern Africa. Specific focus is given to the period between 1650 and circa 1740. The author argues that the original premises remain relevant in ...

  13. Antiretroviral drug resistance: A guide for the southern African clinician

    African Journals Online (AJOL)

    Southern Africa is faced with the daunting prospect of putting several hundred thousand people on ARV therapy (ART) in the next few years.1 ART is the only effective option available to people with advanced HIV disease, and is remarkably effective in improving quality of life, increasing lifespan, dramatically decreasing the ...

  14. Life history and diet of two southern African smoothhound sharks ...

    African Journals Online (AJOL)

    Mustelus mustelus and M. palumbes) off southern Africa are described and compared. Free-swimming male M. mustelus measured 390–1 450 mm total length (TL), whereas females were recorded up to 1 650 mm TL. Most specimens of both ...

  15. Anthropogenic radiative forcing of southern African and Southern Hemisphere climate variability and change

    CSIR Research Space (South Africa)

    Engelbrecht, FA

    2014-10-01

    Full Text Available southern Africa and the Southern Hemisphere. Through a set of AMIP-style experiments, it is demonstrated that including the direct (radiative) effects of aerosols in the simulations decreases the model’s bias in simulating near-surface temperatures. Trends...

  16. Health evaluation of African penguins (Spheniscus demersus) in southern Africa.

    Science.gov (United States)

    Parsons, Nola J; Gous, Tertius A; Schaefer, Adam M; Vanstreels, Ralph E T

    2016-09-20

    The African penguin (Spheniscus demersus) is an endangered seabird that breeds along the coast of Namibia and South Africa, and disease surveillance was identified as a priority for its conservation. Aiming for the establishment of baseline data on the presence of potential pathogens in this species, a comprehensive health assessment (blood smear examination, haematology, biochemistry and serology) was conducted on samples obtained from 578 African penguins at 11 breeding colonies and a rehabilitation centre. There were 68 penguins that were seropositive for at least one of seven pathogens tested: avian encephalomyelitis virus, avian infectious bronchitis virus, avian reovirus, infectious bursal disease virus, Newcastle disease virus, Mycoplasma gallisepticum and Mycoplasma synoviae. All samples were seronegative for avian influenza virus subtypes H5 and H7 and infectious laryngotracheitis virus. The apparent prevalence of Babesia sp. and Borrelia sp. in blood smears was consistent with previous studies. Babesia-infected individuals had a regenerative response of the erythrocytic lineage, an active inflammatory response and hepatic function impairment. These findings indicate that African penguins may be exposed to conservation-significant pathogens in the wild and encourage further studies aiming for the direct detection and/or isolation of these microorganisms.

  17. Honey bees (Hymenoptera: Apidae) of African origin exist in non-africanized areas of the southern United States: evidence from mitochondrial DNA

    Science.gov (United States)

    M.A. Pinto; W.S. Sheppard; J.S. Johnston; W.L. Rubink; R.N. Coulson; N.M. Schiff; I. Kandemir; J.C. Patton

    2007-01-01

    Descendents of Apis mellifera scutellata Lepeletier (Hymenoptera: Apidae) (the Africanized honey bee) arrived in the United States in 1990. Whether this was the first introduction is uncertain. A survey of feral honey bees from non-Africanized areas of the southern United States revealed three colonies (from Georgia, Texas, and New Mexico) with a...

  18. Plio-Pleistocene climate-driven facial morphology in southern African australopithecines

    Science.gov (United States)

    Williams, F. L.; Christensen, B. A.

    2004-12-01

    Intensification of Northern Hemispheric Glaciation (INHG) has been cited as the driving force for climate change in southern Africa, despite the fact that rare and fragmentary continental records for the region allow for only a loose correlation between local faunal events and global climate change. Determining climatic influence from the limited climate history is exacerbated by the difficult chronology for the cave sites. The depositional history of the caves nonetheless reveals a turnover of southern African mammals, and variability, among other forcing factors, have implicated the INHG to explain the evolution of these novel forms. We suggest that evolutionary changes in southern African fauna may have also been driven by a subsequent climate event, the Onset of Walker Circulation (OWC) at ~ 2 Myr. The OWC, with enhanced high frequency climate variability, may have been more dominant than INHG in driving southern African mammalian evolution. For example, Pleistocene Australopithecus robustus, but not Pliocene Australopithecus africanus, exhibits relatively broad palates, postcanine megadonty and deep mandibular corpora that correspond to a dietary niche involving heavy mastication. These adaptations may have been selected for in unstable Pleistocene environments initiated by the OWC. Moreover, the temporal context of Australopithecus robustus, found in the Pleistocene dated caves of Swartkrans, Kromdraai and Drimolen, coincides more closely with the OWC than with the INHG.

  19. The bi-decadal rainfall cycle, Southern Annular Mode and tropical cyclones over the Limpopo River Basin, southern Africa

    Science.gov (United States)

    Malherbe, Johan; Landman, Willem A.; Engelbrecht, Francois A.

    2014-06-01

    The association between bi-decadal rainfall variability over southern Africa and the rainfall contributed by tropical cyclonic systems from the Southwest Indian Ocean (SWIO) provides a potential means towards understanding decadal-scale variability over parts of the region. A multi-decadal period is considered, focusing on the anomalous tropospheric patterns that induced a particularly wet 8-year long sub-period over the Limpopo River Basin. The wet sub-period was also characterized by a larger contribution to rainfall by tropical cyclones and depressions. The findings suggest that a broadening of the Hadley circulation underpinned by an anomalous anticyclonic pattern to the east of southern Africa altered tropospheric steering flow, relative vorticity and moisture contents spatially during the sub-period of 8 years. These circulation modulations induced enhanced potential for tropical systems from the SWIO to cause precipitation over the Limpopo River Basin. The same patterns are also conducive to increasing rainfall over the larger subcontinent, therefore explaining the positive association in the bi-decadal rainfall cycle and rainfall contributed by tropical cyclonic systems from the SWIO. An overview of regional circulation anomlies during alternating near-decadal wet and dry epochs is given. The regional circulation anomalies are also explained in hemispheric context, specifically in relation to the Southern Annular Mode, towards understanding variation over other parts of the Southern Hemisphere at this time scale.

  20. Microstructure-mediated Optical Effects in Southern African Snakes

    Directory of Open Access Journals (Sweden)

    Singh Ishan

    2017-01-01

    Full Text Available The scales of the African Viper Bitis arietans were tested for optical effects. Spectral intensity was recorded at incident angles over the visible spectrum for dark, pale, and ventral scale regions. The lowest spectral intensity recordings were associated with scales which have the greatest level of micro-structuring. Our results indicate that scale appearance in B. arietans is a product of microstructure-mediated optical effects. The optical effect may play a role in improving the ecological performance of the snake in its natural environment.

  1. Microstructure-mediated Optical Effects in Southern African Snakes

    Science.gov (United States)

    Singh, Ishan; Alexander, Graham

    2017-03-01

    The scales of the African Viper Bitis arietans were tested for optical effects. Spectral intensity was recorded at incident angles over the visible spectrum for dark, pale, and ventral scale regions. The lowest spectral intensity recordings were associated with scales which have the greatest level of micro-structuring. Our results indicate that scale appearance in B. arietans is a product of microstructure-mediated optical effects. The optical effect may play a role in improving the ecological performance of the snake in its natural environment.

  2. The impact of ENSO on Southern African rainfall in CMIP5 ocean atmosphere coupled climate models

    Science.gov (United States)

    Dieppois, Bastien; Rouault, Mathieu; New, Mark

    2015-11-01

    We study the ability of 24 ocean atmosphere global coupled models from the Coupled Model Intercomparison Project 5 (CMIP5) to reproduce the teleconnections between El Niño Southern Oscillation (ENSO) and Southern African rainfall in austral summer using historical forced simulations, with a focus on the atmospheric dynamic associated with El Niño. Overestimations of summer rainfall occur over Southern Africa in all CMIP5 models. Abnormal westward extensions of ENSO patterns are a common feature of all CMIP5 models, while the warming of the Indian Ocean that happens during El Niño is not correctly reproduced. This could impact the teleconnection between ENSO and Southern African rainfall which is represented with mixed success in CMIP5 models. Large-scale anomalies of suppressed deep-convection over the tropical maritime continent and enhanced convection from the central to eastern Pacific are correctly simulated. However, regional biases occur above Africa and the Indian Ocean, particularly in the position of the deep convection anomalies associated with El Niño, which can lead to the wrong sign in rainfall anomalies in the northwest part of South Africa. From the near-surface to mid-troposphere, CMIP5 models underestimate the observed anomalous pattern of pressure occurring over Southern Africa that leads to dry conditions during El Niño years.

  3. Variation in Vowel Duration Among Southern African American English Speakers.

    Science.gov (United States)

    Holt, Yolanda Feimster; Jacewicz, Ewa; Fox, Robert Allen

    2015-08-01

    Atypical duration of speech segments can signal a speech disorder. In this study, we examined variation in vowel duration in African American English (AAE) relative to White American English (WAE) speakers living in the same dialect region in the South to characterize the nature of systematic variation between the 2 groups. The goal was to establish whether segmental durations in minority populations differ from the well-established patterns in mainstream populations. Participants were 32 AAE and 32 WAE speakers differing in age who, in their childhood, attended either segregated (older speakers) or integrated (younger speakers) public schools. Speech materials consisted of 14 vowels produced in hVd-frame. AAE vowels were significantly longer than WAE vowels. Vowel duration did not differ as a function of age. The temporal tense-lax contrast was minimized for AAE relative to WAE. Vowels produced by females were significantly longer than vowels produced by males for both AAE and WAE. African American speakers should be expected to produce longer vowels relative to White speakers in a common geographic area. These longer durations are not deviant but represent a typical feature of AAE. This finding has clinical importance in guiding assessments of speech disorders in AAE speakers.

  4. Heavy metal pollution and potential ecological risks in rivers: a case study from southern Italy.

    Science.gov (United States)

    Protano, Carmela; Zinnà, Loredana; Giampaoli, Saverio; Romano Spica, Vincenzo; Chiavarini, Salvatore; Vitali, Matteo

    2014-01-01

    We monitored heavy metal (As, Cd, Hg, and Pb) concentrations in surface water, sediments, and oligochaetes in four major rivers in Calabria (southern Italy) over the course of 1 year. As, Cd, and Pb showed accumulation factors of 10(3)-10(5) for water to sediment and 1-10 for sediment to oligochaetes. Hg showed a water to sediment accumulation factor of 10-100. Finally, Hg concentrations exceeded the Italian quality standard for freshwater in all of the rivers, and As concentrations in sediments exceeded the respective Canadian standard. However, the application of an ecological risk assessment method indicated low risks for all monitored rivers.

  5. Connection between El Niño-Southern Oscillation events and river nitrate concentrations in a Mediterranean river.

    Science.gov (United States)

    Vegas-Vilarrúbia, Teresa; Sigró, Javier; Giralt, Santiago

    2012-06-01

    The causes of interannual nitrate variability in rivers remain uncertain, but extreme climatic events have been suggested as drivers of large nitrate inputs to rivers. Based on a 24-year data set (1983-2006), we suggest that El Niño-Southern Oscillation (ENSO) can affect nitrate behavior in a seasonal extra-tropical stream, the Llobregat (NE Iberian Peninsula), located thousands of kilometers away from the ENSO oscillating system via atmospheric teleconnections. Two commonly used indices, the Southern Oscillation Index (SOI) and the self-calibrating-Palmer Drought Severity Index (scPDSI) showed highly significant correlations with nitrate concentrations, which recurrently increased during La Niña phases, coinciding with severe droughts. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Animal-adapted members of the Mycobacterium tuberculosis complex endemic to the southern African subregion

    Directory of Open Access Journals (Sweden)

    Charlene Clarke

    2016-02-01

    Full Text Available Members of the Mycobacterium tuberculosis complex (MTC cause tuberculosis (TB in both animals and humans. In this article, three animal-adapted MTC strains that are endemic to the southern African subregion – that is, Mycobacterium suricattae, Mycobacterium mungi, and the dassie bacillus – are reviewed with a focus on clinical and pathological presentations, geographic distribution, genotyping methods, diagnostic tools and evolution. Moreover, factors influencing the transmission and establishment of TB pathogens in novel host populations, including ecological, immunological and genetic factors of both the host and pathogen, are discussed. The risks associated with these infections are currently unknown and further studies will be required for greater understanding of this disease in the context of the southern African ecosystem.Keywords: dassie bacillus; ecology; evolution; host jump; Mycobacterium mungi; Mycobacterium suricattae; Mycobacterium tuberculosis complex; phylogeny

  7. The history of African gene flow into Southern Europeans, Levantines, and Jews.

    Science.gov (United States)

    Moorjani, Priya; Patterson, Nick; Hirschhorn, Joel N; Keinan, Alon; Hao, Li; Atzmon, Gil; Burns, Edward; Ostrer, Harry; Price, Alkes L; Reich, David

    2011-04-01

    Previous genetic studies have suggested a history of sub-Saharan African gene flow into some West Eurasian populations after the initial dispersal out of Africa that occurred at least 45,000 years ago. However, there has been no accurate characterization of the proportion of mixture, or of its date. We analyze genome-wide polymorphism data from about 40 West Eurasian groups to show that almost all Southern Europeans have inherited 1%-3% African ancestry with an average mixture date of around 55 generations ago, consistent with North African gene flow at the end of the Roman Empire and subsequent Arab migrations. Levantine groups harbor 4%-15% African ancestry with an average mixture date of about 32 generations ago, consistent with close political, economic, and cultural links with Egypt in the late middle ages. We also detect 3%-5% sub-Saharan African ancestry in all eight of the diverse Jewish populations that we analyzed. For the Jewish admixture, we obtain an average estimated date of about 72 generations. This may reflect descent of these groups from a common ancestral population that already had some African ancestry prior to the Jewish Diasporas.

  8. The history of African gene flow into Southern Europeans, Levantines, and Jews.

    Directory of Open Access Journals (Sweden)

    Priya Moorjani

    2011-04-01

    Full Text Available Previous genetic studies have suggested a history of sub-Saharan African gene flow into some West Eurasian populations after the initial dispersal out of Africa that occurred at least 45,000 years ago. However, there has been no accurate characterization of the proportion of mixture, or of its date. We analyze genome-wide polymorphism data from about 40 West Eurasian groups to show that almost all Southern Europeans have inherited 1%-3% African ancestry with an average mixture date of around 55 generations ago, consistent with North African gene flow at the end of the Roman Empire and subsequent Arab migrations. Levantine groups harbor 4%-15% African ancestry with an average mixture date of about 32 generations ago, consistent with close political, economic, and cultural links with Egypt in the late middle ages. We also detect 3%-5% sub-Saharan African ancestry in all eight of the diverse Jewish populations that we analyzed. For the Jewish admixture, we obtain an average estimated date of about 72 generations. This may reflect descent of these groups from a common ancestral population that already had some African ancestry prior to the Jewish Diasporas.

  9. The History of African Gene Flow into Southern Europeans, Levantines, and Jews

    Science.gov (United States)

    Moorjani, Priya; Patterson, Nick; Hirschhorn, Joel N.; Keinan, Alon; Hao, Li; Atzmon, Gil; Burns, Edward; Ostrer, Harry; Price, Alkes L.; Reich, David

    2011-01-01

    Previous genetic studies have suggested a history of sub-Saharan African gene flow into some West Eurasian populations after the initial dispersal out of Africa that occurred at least 45,000 years ago. However, there has been no accurate characterization of the proportion of mixture, or of its date. We analyze genome-wide polymorphism data from about 40 West Eurasian groups to show that almost all Southern Europeans have inherited 1%–3% African ancestry with an average mixture date of around 55 generations ago, consistent with North African gene flow at the end of the Roman Empire and subsequent Arab migrations. Levantine groups harbor 4%–15% African ancestry with an average mixture date of about 32 generations ago, consistent with close political, economic, and cultural links with Egypt in the late middle ages. We also detect 3%–5% sub-Saharan African ancestry in all eight of the diverse Jewish populations that we analyzed. For the Jewish admixture, we obtain an average estimated date of about 72 generations. This may reflect descent of these groups from a common ancestral population that already had some African ancestry prior to the Jewish Diasporas. PMID:21533020

  10. Water quality index for Al-Gharraf River, southern Iraq

    Directory of Open Access Journals (Sweden)

    Salam Hussein Ewaid

    2017-06-01

    Full Text Available The Water Quality Index has been developed mathematically to evaluate the water quality of Al-Gharraf River, the main branch of the Tigris River in the south of Iraq. Water samples were collected monthly from five sampling stations during 2015–2016, and 11 parameters were analyzed: biological oxygen demand, total dissolved solids, the concentration of hydrogen ions, dissolved oxygen, turbidity, phosphates, nitrates, chlorides, as well as turbidity, total hardness, electrical conductivity and alkalinity. The index classified the river water, without including turbidity as a parameter, as good for drinking at the first station, poor at stations 2, 3, 4 and very poor at station 5. When turbidity was included, the index classified the river water as unsuitable for drinking purposes in the entire river. The study highlights the importance of applying the water quality indices which indicate the total effect of the ecological factors on surface water quality and which give a simple interpretation of the monitoring data to help local people in improving water quality.

  11. Bromus tectorum expansion and biodiversity loss on the Snake River Plain, southern Idaho, USA

    Science.gov (United States)

    N. L. Shaw; V. A. Saab; S. B. Monsen; T. D. Rich

    1999-01-01

    The Snake River Plain forms a 6 million ha arc-shaped depression across southern Idaho. Basalt flows, fresh water sediments, loess and volcanic deposits cover its surface. Elevation increases eastward from 650 to 2,150 m altitude. Climate is semi-arid with annual precipitation ranging from 150 to 400 mm, arriving primarily in winter and spring. Native shrub steppe...

  12. Southern Africa in water crisis – A case study of the Pangara River ...

    African Journals Online (AJOL)

    Southern Africa in water crisis – A case study of the Pangara River water shortage, 1987–1996: Towards a resource-based conflict management and resolution perspective. ... The first is an assessment of the nature of the environmental and regional weather patterns leading to predictable water shortages. This is followed ...

  13. An Investigation of the Migration of Africanized Honey Bees into the Southern United States

    Science.gov (United States)

    Navarro, Hector

    1997-01-01

    It is estimated that Apis mellifera scutellata, a honey bee subspecies from Africa, now extends over a 20 million square kilometer range that includes much of South America and practically all of Central America, and recently has been introduced to the southern United States. African honeybees were introduced into Brazil in 1956 by a Brazilian geneticist, Mr. Warwick Kerr. At the insistence of the Brazilian Ministry of Agriculture, in 1957, 26 colonies were accidentally released in a eucalyptus forest outside S5o Paulo. The swelling front of the bees was recorded as traveling between 80 and 500 kilometers a year. David Roubik, one of the original killer bee team members estimated that there were one trillion individual Africanized/African honey bees in Latin America. An estimate that is thought to be conservative.

  14. Nematode parasites of the channids in Orogodo River, Southern ...

    African Journals Online (AJOL)

    The distribution of infrapopulations of the parasites varied significantly with size class and weight of the fish peaking in most cases in larger size classes. The chemical parameters of the river water at this site showed the water to be stressed with high BOD and nutrients levels. The intensity of the parasites in the host fish ...

  15. Water quality assessment of the Siluko River, southern Nigeria ...

    African Journals Online (AJOL)

    The water quality of the Siluko River, Edo State, Nigeria was investigated from March to August 2015 to determine its suitability for drinking and usage for domestic purposes. Water samples collected from three stations were tested for thirteen physico-chemical parameters using standard analytical procedures. Temperature ...

  16. Tracking the movements of a post-nesting Southern River Terrapin (Batagur affinis edwardmolli)

    Science.gov (United States)

    Chen, Pelf-Nyok; Wong, Adrian

    2015-09-01

    A Southern River Terrapin (Batagur affinis edwardmolli) Conservation Project was initiated on one terrapin nesting bank in 2011, following the discovery of a River Terrapin population in the Kemaman River, Terengganu in 2010. Since this project was initiated, Turtle Conservation Society of Malaysia (TCS) was instrumental in the gazettement of three nesting banks along the Kemaman River, from which all River Terrapin eggs are collected for incubation. However, there are at least a dozen other "unprotected" nesting banks along the river, where all eggs were collected for human consumption. This project attempted to determine the movements of a post-nesting River Terrapin, with hopes that it would provide the preliminary baseline information on the utilization of adjacent nesting banks. The solution was a GPS tracking device that transmitted coordinates every hour over cellular networks. Location-based data was sent via Short Message Service (SMS) to our own SMS gateway running on a Raspberry Pi credit-card size computer, which was then logged in a database and presented graphically via Google Maps. It was a complete tracking and monitoring system. This solution enabled researchers to remotely track the movements of a River Terrapin, hence reducing the costs of research. The movements of a post-nesting River Terrapin were tracked for eight days before the battery was drained. On the third day, this River Terrapin ascended an adjacent riverbank and spent less than an hour on the bank, presumably to deposit her remaining eggs. This study confirmed that River Terrapins do utilize other suitable nesting banks if/whenever available. Results from such tracking studies will be used to leverage on the protection of adjacent nesting banks, thus providing greater protection for the critically endangered River Terrapins.

  17. The coherent variability of African river flows : composite climate ...

    African Journals Online (AJOL)

    The composite structure of the ocean and atmosphere around Africa is studied in the context of river flow variability. Annual streamflows are analysed for the Blue and White Nile, Congo, Niger, Senegal, Zambezi, and Orange Rivers, and inflow to Lake Malawi. Spectral energy is concentrated in 6.6- and 2.4-year bands.

  18. Use of landscape-level river signatures in conservation planning: a South African case study

    CSIR Research Space (South Africa)

    Roux, D

    2002-12-01

    Full Text Available : http://www.consecol.org/vol6/iss2/art6 1CSIR; 2Albany Museum Insight Use of Landscape-level River Signatures in Conservation Planning: a South African Case Study Dirk Roux1, Ferdy de Moor2, Jim Cambray2, and Helen Barber-James2... biota (Cowling and Pressey Conservation Ecology 6(2): 6. http://www.consecol.org/vol6/iss2/art6 The most significant river system that flows though the GAENP is the Sundays River and its tributaries. Darlington Dam is the largest man...

  19. Microbiological characterisation of southern African medicinal and cosmetic clays.

    Science.gov (United States)

    Mpuchane, Sisai F; Ekosse, Georges-Ivo E; Gashe, Berhanu A; Morobe, Isaac; Coetzee, Stephan H

    2010-02-01

    The effects of traditionally used medicinal and cosmetic clays in southern Africa on selected microorganisms were studied using microbiological media. The clay pH, microchemical composition, kind of associated microorganisms and antimicrobial activity of clays against test microorganisms were determined. The clays contained varying numbers of microorganisms which ranged from 0 up to 105 CFU/g. Clay pH ranged from 2.3-8.9. Neither Escherichia coli, nor other faecal coliforms were detected. Clays of pH value of Clays which were active against test microorganisms had Na(2)O, Al(2)O(3), SiO(2), SO(3), CuO or Cl(2)O as major components. Microbial activity of clays was attributed mainly to low pH but cations such as Cu, Al, S or Cl and various anions might have contributed to the microbicidal effects. No antimicrobial activity was established for many of the clays commonly used in the treatment of common ailments of microbial origin.

  20. Population dynamics of the Giant African River prawn ...

    African Journals Online (AJOL)

    West African Journal of Applied Ecology. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 9, No 1 (2006) >. Log in or Register to get access to full text downloads.

  1. Genetic structure of drone congregation areas of Africanized honeybees in southern Brazil

    Directory of Open Access Journals (Sweden)

    Thais Collet

    2009-01-01

    Full Text Available As yet, certain aspects of the Africanization process are not well understood, for example, the reproductive behavior of African and European honeybees and how the first Africanized swarms were formed and spread. Drone congregation areas (DCAs are the ideal place to study honeybee reproduction under natural conditions since hundreds of drones from various colonies gather together in the same geographical area for mating. In the present study, we assessed the genetic structure of seven drone congregations and four commercial European-derived and Africanized apiaries in southern Brazil, employing seven microsatellite loci for this purpose. We also estimated the number of mother-colonies that drones of a specific DCA originated from. Pairwise comparison failed to reveal any population sub-structuring among the DCAs, thus indicating low mutual genetic differentiation. We also observed high genetic similarity between colonies of commercial apiaries and DCAs, besides a slight contribution from a European-derived apiary to a DCA formed nearby. Africanized DCAs seem to have a somewhat different genetic structure when compared to the European.

  2. Hunter-gatherer genomic diversity suggests a southern African origin for modern humans.

    Science.gov (United States)

    Henn, Brenna M; Gignoux, Christopher R; Jobin, Matthew; Granka, Julie M; Macpherson, J M; Kidd, Jeffrey M; Rodríguez-Botigué, Laura; Ramachandran, Sohini; Hon, Lawrence; Brisbin, Abra; Lin, Alice A; Underhill, Peter A; Comas, David; Kidd, Kenneth K; Norman, Paul J; Parham, Peter; Bustamante, Carlos D; Mountain, Joanna L; Feldman, Marcus W

    2011-03-29

    Africa is inferred to be the continent of origin for all modern human populations, but the details of human prehistory and evolution in Africa remain largely obscure owing to the complex histories of hundreds of distinct populations. We present data for more than 580,000 SNPs for several hunter-gatherer populations: the Hadza and Sandawe of Tanzania, and the ≠Khomani Bushmen of South Africa, including speakers of the nearly extinct N|u language. We find that African hunter-gatherer populations today remain highly differentiated, encompassing major components of variation that are not found in other African populations. Hunter-gatherer populations also tend to have the lowest levels of genome-wide linkage disequilibrium among 27 African populations. We analyzed geographic patterns of linkage disequilibrium and population differentiation, as measured by F(ST), in Africa. The observed patterns are consistent with an origin of modern humans in southern Africa rather than eastern Africa, as is generally assumed. Additionally, genetic variation in African hunter-gatherer populations has been significantly affected by interaction with farmers and herders over the past 5,000 y, through both severe population bottlenecks and sex-biased migration. However, African hunter-gatherer populations continue to maintain the highest levels of genetic diversity in the world.

  3. Genetic structure of drone congregation areas of Africanized honeybees in southern Brazil.

    Science.gov (United States)

    Collet, Thais; Cristino, Alexandre Santos; Quiroga, Carlos Fernando Prada; Soares, Ademilson Espencer Egea; Del Lama, Marco Antônio

    2009-10-01

    As yet, certain aspects of the Africanization process are not well understood, for example, the reproductive behavior of African and European honeybees and how the first Africanized swarms were formed and spread. Drone congregation areas (DCAs) are the ideal place to study honeybee reproduction under natural conditions since hundreds of drones from various colonies gather together in the same geographical area for mating. In the present study, we assessed the genetic structure of seven drone congregations and four commercial European-derived and Africanized apiaries in southern Brazil, employing seven microsatellite loci for this purpose. We also estimated the number of mother-colonies that drones of a specific DCA originated from. Pairwise comparison failed to reveal any population sub-structuring among the DCAs, thus indicating low mutual genetic differentiation. We also observed high genetic similarity between colonies of commercial apiaries and DCAs, besides a slight contribution from a European-derived apiary to a DCA formed nearby. Africanized DCAs seem to have a somewhat different genetic structure when compared to the European.

  4. Water pollution and cyanobacteria's variation of rivers surrounding southern Taihu Lake, China.

    Science.gov (United States)

    Sun, Mingyang; Huang, Linglin; Tan, Lisha; Yang, Zhe; Baig, Shams Ali; Sheng, Tiantian; Zhu, Hong; Xu, Xinhua

    2013-05-01

    The water quality and cyanobacterial variation of rivers surrounding southern Taihu Lake, China were purposively monitored from 2008 to 2010. Trophic level index (TLI) was used to evaluate the trophic levels of southern Taihu Lake. Results showed a considerable decline in the monitored data compared with 2007, and the data showed downward trends year after year. The TLI decreased from 55.6 to 51.3, which implied that southern Taihu Lake was mildly eutrophic. The water quality and cyanobacterial variation indicated a positive response to the adopted control measures in the southern Taihu Lake basin, but the intra- and inter-annual variability was still quite varied. High concentrations of nitrogen and phosphorus typically lead to algae outbreaks, however, the cyanobacteria growth may result in a decline of the concentration of nitrogen and phosphorus. Temperature and other weather conditions are also important factors for algae outbreaks; the risk of blue-green algal blooms still persists.

  5. Toxicity of trace metals to Acartia tonsa in the Elizabeth River and southern Chesapeake Bay

    Science.gov (United States)

    Sunda, W. G.; Tester, P. A.; Huntsman, S. A.

    1990-03-01

    Dissolved zinc and copper and free cupric ions were present at high concentrations in water from the Elizabeth River estuary (a polluted tributary of the southern Chesapeake Bay) when compared to values in nearby Hampton Roads and lower Chesapeake Bay. Zinc concentrations at three stations in the Elizabeth River ranged from 87 to 1550 nM compared to values of 3·1 to 16 nM at four stations in the southern Chesapeake Bay. Likewise, free cupric ion concentration ranged from 10 -11·6 to 10 -10·1 M at the Elizabeth River stations, but was appreciably lower (10 -12·3 to 10 -12·6 M) in samples from Hampton Roads and the lower bay. In bioassays conducted with the copepod Acartia tonsa, the survival of naupliar larvae was much lower in Elizabeth River samples, containing high levels of copper and zinc, than in samples from the Chesapeake Bay or Newport River estuary which contained much lower levels of these metals. Based on previous results in trace metal ion buffered media, measured free cupric ion concentrations and estimated free zinc ion concentrations appear to have been high enough in the Elizabeth River samples to account for at least some of the observed decrease in larval survival. Furthermore, the addition of chelators, EDTA and NTA, that complex and detoxify copper and zinc (as well as cadmium, nickel and lead) significantly increased larval survival in the Elizabeth River samples. These results strongly support the hypothesis that elevated levels of copper and zinc (and possibly other toxic trace metals) occur at sufficiently high concentrations in Elizabeth River water to adversely affect Acartia tonsa and other sensitive estuarine organisms.

  6. Ecological Research on South African rivers - a preliminary synthesis

    CSIR Research Space (South Africa)

    O'Keeffe, JH

    1986-01-01

    Full Text Available , and therefore steeper, faster flowing, and with poorly developed floodplains. Considerable effort was devoted to understanding the consequences and effects of pollution in rivers, particularly through changes in the invertebrate fauna. In the last thirty years a...

  7. With or without us? An audit of disability research in the southern African region

    Directory of Open Access Journals (Sweden)

    Judith McKenzie

    2014-06-01

    Full Text Available Background: Disability research in the global South has not received significant critical consideration as to how it can be used to challenge the oppression and marginalisation of people with disabilities in low-income and middle-income countries. The Southern Africa Federation of the Disabled (SAFOD embarked on a programme to use research to influence policy and practice relating to people with disabilities in Southern Africa, and commissioned an audit on research expertise in the region. In this article, a research audit is reported on and situated in a framework of mancipatory research.Objectives: This article sets out to describe a preliminary audit of disability research in the southern African region and to draw conclusions about the current state of disability research in the region and make recommendations.Method: The research method entailed working with disability researchers in the ten SAFOD member countries and utilising African disability networks hosted on electronic media. Disability researchers working in the region completed 87 questionnaires, which were reviewed through a thematic analysis.Results: The discussion of results provides a consideration of definitions of disability; the understanding of disability rights, research topics and methodologies; the participation of people with disabilities in research; and the challenges and opportunities for using research to inform disability activism.Conclusion: The conclusion highlights critical issues for future research in the region, and considers how a disability researcher database can be used as a tool for disability organisations to prioritise research that serves a disability rights agenda.

  8. Circulation controls on southern African precipitation in coupled models: The role of the Angola Low

    Science.gov (United States)

    Munday, Callum; Washington, Richard

    2017-01-01

    In southern Africa, models from the latest Coupled Model Intercomparison Project produce a wide variety of rainfall climatologies. Differences between models in rainfall amount reach 70% in the rainy season (December-February; DJF), and the median model overestimates rainfall by between 15 and 40% throughout the annual cycle. This paper investigates the role of an understudied regional circulation feature, the Angola Low, in differentiating between model estimates of precipitation. In austral spring, the Angola Low is a heat low, driven by strong surface heating whereas in DJF it is more similar to a tropical low and is associated with moist instability. In the austral summer, we find that the simulated strength of the Angola Low is associated with between 40 and 60% of the intermodel variability in model mean rainfall across the subcontinent. The relationship is particularly strong along a northwest, southeast axis aligned from Angola down to the Mozambican Channel. Along this axis, models with stronger Angola Lows simulate enhanced, by up to 50 g kg-1 ms-1, northeasterly and northwesterly moisture transport. The enhanced southward moisture flux in models with relatively deep Angola Lows increases the rate of moisture convergence in central areas of the subcontinent and reduces moisture divergence across the Mozambican coast. The results highlight the need to better understand the links between the Angola Low and southern African rainfall and suggest that improving the simulation of the Angola Low can help to constrain model estimates of southern African rainfall.

  9. The recreational value of river inflows into South African estuaries

    African Journals Online (AJOL)

    estimate the value of recreational benefits that would result at 40 South African estuaries if water-inflow reductions were averted. The studies were undertaken .... population and demand pressure. 'Turning back the clock' to ..... Environmental Affairs and Tourism, Pretoria, South Africa. LAMBERTH S and TURPIE J (2003) ...

  10. Reemergence of rabies in the southern Han river region, Korea.

    Science.gov (United States)

    Oem, Jae-Ku; Kim, Seong-Hee; Kim, Yeon-Hee; Lee, Myoung-Heon; Lee, Kyoung-Ki

    2014-07-01

    Recently, 11 cases of animal rabies were reported in the southern region (Suwon and Hwaseong cities) of Gyeonggi Province, South Korea. The cases were temporally separated into two cases in dogs (Canis lupus familiaris) in spring 2012 and nine cases in domestic animals and wildlife in winter 2012-13. All carcasses were submitted for histopathologic examination and viral antigen identification. Sequences of the glycoprotein, nucleoprotein, and glycoprotein-large polymerase protein intergenic noncoding loci of the 11 strains were determined and compared with published reference sequences. All rabies strains were closely related to the Gangwon strains isolated in 2008-09, suggesting that the rabies virus strains isolated in Gyeonggi were introduced from Gangwon Province.

  11. A theological perspective on migrants and migration focussing on the Southern African Development Community (SADC

    Directory of Open Access Journals (Sweden)

    Botha, Nico A.

    2013-05-01

    Full Text Available The main purpose of the paper is to draw some contours of a theology of migration. The specific focus in the paper is on the Southern African Development Community (SADC which constitutes a very complex situation of human migration from neighbouring countries to South Africa. The praxis cycle is called into service to construct a theology of migration informed by insertion, context analysis, theological reflection and strategic planning. The main thesis of the paper is that a theology of migration should as a bare minimum reflect the following dimensions: a theological theology, i.e. the language about God in the context of migration, a narrative theology, a liturgical-communal theology and an intercultural and interreligious theology. The proposal offered on strategic planning is aimed at the radical transformation of relationships between South Africans and migrants.

  12. Methods to determine the impact of rainfall on fuels and burned area in southern African savannas

    CSIR Research Space (South Africa)

    Archibald, S

    2010-11-01

    Full Text Available /Aux fins d'examen seulement Southern African re regimes as revealed by remote sensing S. Archibald1;2;6, R.J. Scholes1;2, D.P. Roy3, G.Roberts4, L. Boschetti5 April 9, 2010 1CSIR, Ecosystems Processes and Dynamics, PO Box 395, Pretoria 0001, South... uncultivated but grazed land; cultivated land; and settlements). While annual mean burnt381 area fraction (Figure 5A), maximum re size (Figure 5D), Fire Radiative Power (Figure 5E),382 and cumulative re-a ected area (Figure 3) decrease as human impact...

  13. Studies in the southern African species of Justicia and Siphonoglossa (Acanthaceae: seeds

    Directory of Open Access Journals (Sweden)

    K. L. Immelman

    1990-12-01

    Full Text Available The seeds of all species of Justicia (except J. thymifolia (Nees C.B. Cl. and Siphonoglossa in the southern African region (as defined by the Flora of southern Africa were examined with the Scanning Electron Microscope. A wide range of different seed surfaces were seen, many of which could be correlated with other characters to further reinforce grouping of species into sections. However, some species that on other characters, would be placed together, had widely differing seed testas. Gross surface morphology varied from smooth to colliculate, irregularly rugose, reticulate with the ridges variously arranged, wheel-shaped (radiate or ammonite-like, with a central ridge or with multicellular barbed scales. The seeds were without hairs, unlike some American species sometimes considered to belong in Justicia (Graham 1989. Micromorphology also provided useful characters, with seeds being reticulate, papillate, minutely or deeply rugose or with one to many crystals visible. Critical-point drying was sometimes helpful in viewing microstructure.

  14. Introgressive hybridization in southern African baboons shapes patterns of mtDNA variation.

    Science.gov (United States)

    Keller, C; Roos, C; Groeneveld, L F; Fischer, J; Zinner, D

    2010-05-01

    Species, as main evolutionary units have long been considered to be morphological entities with limited hybridization potential. The occurrence of taxa which maintain morphological distinctness despite extensive hybridization is an interesting phenomenon. To understand the evolution of these taxa, descriptions of contemporary morphological and genetic variation are essential, also to reconstruct sound phylogenies. Baboons, with their wide geographic range, variant morphotypes, and extensive hybridization offer an intriguing model for those studies. We focus on the complex situation in southern Africa that, in contrast to east Africa, has been neglected in terms of baboon hybridization history. We aim to clarify the distribution and identify possible overlapping zones between different, previously described mitochondrial (mt) DNA clades of baboons that do not match with the ranges of traditionally recognized species. On the basis of the widespread sampling and mitochondrial cytochrome b gene sequencing, we constructed a phylogenetic tree that separates representatives of the two southern African baboon species, yellow and chacma baboons, into six clades: southern, northern and eastern chacmas, Kinda baboons and southern and Luangwa yellow baboons. The ranges of the chacma clades come into close contact or overlap in two regions in the Republic of South Africa and Namibia. Our phylogenetic reconstruction reveals mitochondrial paraphyly for chacma and yellow baboons, which is probably caused by introgressive hybridization and subsequent nuclear swamping, whereby males of the chacma morphotype population from the south invaded the yellow morphotype population in the north bringing their morphotype into a population that maintained its yellow baboon mtDNA.

  15. Anti-HIV activity of southern African plants: Current developments, phytochemistry and future research.

    Science.gov (United States)

    Prinsloo, Gerhard; Marokane, Cynthia K; Street, Renée A

    2018-01-10

    The African continent is home to a large number of higher plant species used over centuries for many applications, which include treating and managing diseases such as HIV. Due to the overwhelming prevalence and incidence rates of HIV, especially in sub-Saharan Africa, it is necessary to develop new and affordable treatments. The article provides an extensive overview of the status on investigation of plants from the southern African region with ethnobotanical use for treating HIV or HIV-related symptoms, or the management of HIV. The review also provide an account of the in vitro assays, anti-viral activity and phytochemistry of these plants. Peer-reviewed articles investigating plants with ethnobotanical information for the treatment or management of HIV or HIV-related symptoms from the southern African region were acquired from Science Direct, PubMed central and Google Scholar. The selection criteria was that (1) plants should have a record of traditional/popular use for infectious or viral diseases, HIV treatment or symptoms similar to HIV infection, (2) if not traditionally/popularly used, plants should be closely related to plants with popular use and HIV activity identified by means of in vitro assays, (3) plants should have been identified scientifically, (4) should be native to southern African region and (5) anti-HIV activity should be within acceptable ranges. Many plants in Africa and specifically the southern African region have been used for the treatment of HIV or HIV related symptoms and have been investigated suing various in vitro techniques. In vitro assays using HIV enzymes such as reverse transcriptase (RT), integrase (IN) and protease (PR), proteins or cell-based assays have been employed to validate the use of these plants with occasional indication of the selectivity index (SI) or therapeutic index (TI), with only one study, that progressed to in vivo testing. The compounds identified from plants from southern Africa is similar to compounds

  16. Assessment of potentially harmful elements pollution in the Calore River basin (Southern Italy).

    Science.gov (United States)

    Zuzolo, Daniela; Cicchella, Domenico; Catani, Vittorio; Giaccio, Lucia; Guagliardi, Ilaria; Esposito, Libera; De Vivo, Benedetto

    2017-06-01

    The geographical distribution of concentration values for harmful elements was determined in the Campania region, Italy. The study area consists of the drainage basin of the River Calore, a tributary of the river Volturno, the largest Southern Italian river. The results provide reliable analytical data allowing a quantitative assessment of the trace element pollution threat to the ecosystem and human health. Altogether 562 stream sediment samples were collected at a sampling density of 1 site per 5 km2. All samples were air-dried, sieved to urban settlements and industrial areas. The enrichment factor of these elements is 3-4 times higher than the background values. The southwestern area of the basin is characterized by a moderate/high degree of contamination, just where the two busiest roads of the area run and the highest concentration of industries occurs.

  17. A multibiomarker approach in rats to assess the impact of pollution on Sinos River, Southern Brazil.

    Science.gov (United States)

    Rechenmacher, C; Siebel, A M; Goldoni, A; Klauck, C R; Sartori, T; Rodrigues, M T; Rodrigues, M A S; Gehlen, G; Ardenghi, P G; Silva, L B

    2010-12-01

    The aim of this study was to determine the feasibility of combining water quality analysis with different biomarkers to characterise the relationship between anthropogenic contamination and biotic response in the Sinos River, southern Brazil. Wistar rats were studied using three biomarkers combined with physical, chemical and microbiological analysis to assess the effects of pollution at four sampling sites. The induction of oxidative stress was quantified by MDA levels in peripheral blood, lymphocyte DNA damage was determined using the comet assay, and histopathological changes were analysed in the liver. After sampling, animals were allowed to drink the river water during a 48 hours period. No increase in oxidative stress and DNA damage was observed. However, liver damage was observed in the animals exposed to water samples, indicating that the Sinos River is contaminated with hepatotoxic substances. Water analyses confirmed that water quality decreased downriver.

  18. A multibiomarker approach in rats to assess the impact of pollution on Sinos River, Southern Brazil

    Directory of Open Access Journals (Sweden)

    C. Rechenmacher

    Full Text Available The aim of this study was to determine the feasibility of combining water quality analysis with different biomarkers to characterise the relationship between anthropogenic contamination and biotic response in the Sinos River, southern Brazil. Wistar rats were studied using three biomarkers combined with physical, chemical and microbiological analysis to assess the effects of pollution at four sampling sites. The induction of oxidative stress was quantified by MDA levels in peripheral blood, lymphocyte DNA damage was determined using the comet assay, and histopathological changes were analysed in the liver. After sampling, animals were allowed to drink the river water during a 48 hours period. No increase in oxidative stress and DNA damage was observed. However, liver damage was observed in the animals exposed to water samples, indicating that the Sinos River is contaminated with hepatotoxic substances. Water analyses confirmed that water quality decreased downriver.

  19. Thrust belt advance versus sediment-flux steering - Late Pleistocene river migrations in the southern Caucasus

    Science.gov (United States)

    von Suchodoletz, Hans; Gärtner, Andreas; Hoth, Silvan; Umlauft, Josefine; Sukhishvili, Lasha; Faust, Dominik

    2017-04-01

    One response of rivers toward allogenic controls is large-scale river channel migration in the form of avulsions or progressive lateral migrations (combing) that are widespread phenomena around the world during the late Quaternary. Sediment-flux steering, i.e. a lateral shift of rivers against a tectonically driven subsidence trend promoted by transverse sediment discharge exerts such control. Evidence for this mechanism to operate stems from numerous field and experimental studies in extensional settings, characterized by commonly small-sized transverse catchments compared with that of the main river and/or volcaniclastic sedimentation. For the first time, this study investigates sediment-flux steering in a contractional tectonic setting with relatively large-sized transverse catchments compared with that of the main river. Geomorphologic, geochronologic, and heavy mineral provenance analyses were complemented with tectonomorphometric data to investigate late Quaternary channel migrations of the Kura River in the southern foreland basin of the Greater Caucasus. Large-scale migrations of the course of the Kura River during the late Quaternary reflect the interplay between a continuing southwestward advance of the Kura Fold-and-Thrust-Belt, leading to uplift in the NE and by climatically-triggered sediment-flux steering caused by aggradation phases of transverse rivers with comparatively large catchment areas in the Lesser Caucasus. During generally warmer periods such as the Holocene with fluvial incision and low sediment supply from the transverse rivers, the main Kura River could follow its tectonically driven trend toward the southwest. In contrast, during generally colder periods such as the upper late Pleistocene, sediment-flux steering caused by aggradation of the transverse rivers forced the main Kura River to migrate >10 km against that tectonically induced trend toward the northeast. Generally, besides improving our understanding of the coupling between

  20. High genetic connectivity among estuarine populations of the riverbream Acanthopagrus vagus along the southern African coast

    Science.gov (United States)

    Oosthuizen, Carel J.; Cowley, Paul D.; Kyle, Scotty R.; Bloomer, Paulette

    2016-12-01

    Physical and/or physiological constraints are assumed to isolate fish populations confined to or dependent on estuarine habitats. Strong isolation by distance is thus expected to affect connectivity. Such structuring has important implications for sustainable utilisation and replenishment of estuarine stocks that are heavily exploited. Here we present a preliminary investigation of the phylogenetic relationships of the riverbream (Acanthopagrus species) along the southern African coast and the geographic genetic structure of what appears to be a locally endemic species or lineage. Mitochondrial DNA (mtDNA) cytochrome b sequences support the notion that the species occurring along the southern African coast is A. vagus and not A. berda as previously thought. Yet, the taxonomy of this widespread Indo-West Pacific species or species-complex requires more in-depth investigation. No genetic differentiation was detected among estuarine populations of A. vagus based on the analyses of mtDNA ND2 gene sequences and 10 polymorphic nuclear microsatellite markers. The star-like genealogy and statistical analyses are consistent with a recent population expansion event. Spatial analyses of microsatellite genotypes fail to reject the null hypothesis of panmixia, indicative of a recent population expansion or ongoing gene flow between different estuaries. The northern localities were identified as containing most of the observed variation. This study not only provides insight into the phylogenetic relationship of A. vagus relative to other Acanthopagrus species but also sheds light on the demographic history and contemporary gene flow of the species.

  1. Factor analysis as a tool in groundwater quality management: two southern African case studies

    Science.gov (United States)

    Love, David; Hallbauer, Dieter; Amos, Amos; Hranova, Roumiana

    Although developed as a tool in the social sciences, R-mode factor analysis, a multivariate statistical tool, has proven highly effective in studies of groundwater quality. The technique examines the relationships between variables (such as chemical parameters in groundwater), which are shown by a number of cases (such as sampling points). In this study, two examples are presented. The first is of groundwater around a southern African iron ore mine and the second is of groundwater in the vicinity of a southern African municipal sewage disposal works. Groundwater samples were collected, their chemistry analysed and factor analysis was performed on each of the chemical datasets. In the first case study, factor analysis successfully separated signatures due to uncontaminated groundwater (calcium, magnesium and bicarbonate), agricultural activities (potassium and ammonium) and mining activities (sodium, chloride and sulphate). In the second case study, factor analysis did identify a chemical signature (nitrate and phosphate; minor iron) related to the sewage works-but since this signature involved parameters that were within regulated limits, the finding was of limited value for management purposes. Thus although R-mode factor analysis can be a valuable tool studies of groundwater quality, this is not always the case. Multivariate statistical techniques like factor analysis should thus be used as supplementary to, but not in replacement of, conventional groundwater quality data treatment methods.

  2. Correlated genetic and ecological diversification in a widespread southern African horseshoe bat.

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    Samantha Stoffberg

    Full Text Available The analysis of molecular data within a historical biogeographical framework, coupled with ecological characteristics can provide insight into the processes driving diversification. Here we assess the genetic and ecological diversity within a widespread horseshoe bat Rhinolophus clivosus sensu lato with specific emphasis on the southern African representatives which, although not currently recognized, were previously described as a separate species R. geoffroyi comprising four subspecies. Sequence divergence estimates of the mtDNA control region show that the southern African representatives of R. clivosus s.l. are as distinct from samples further north in Africa than they are from R. ferrumequinum, the sister-species to R. clivosus. Within South Africa, five genetically supported geographic groups exist and these groups are corroborated by echolocation and wing morphology data. The groups loosely correspond to the distributions of the previously defined subspecies and Maxent modelling shows a strong correlation between the detected groups and ecoregions. Based on molecular clock calibrations, it is evident that climatic cycling and related vegetation changes during the Quaternary may have facilitated diversification both genetically and ecologically.

  3. Correlated genetic and ecological diversification in a widespread southern African horseshoe bat.

    Science.gov (United States)

    Stoffberg, Samantha; Schoeman, M Corrie; Matthee, Conrad A

    2012-01-01

    The analysis of molecular data within a historical biogeographical framework, coupled with ecological characteristics can provide insight into the processes driving diversification. Here we assess the genetic and ecological diversity within a widespread horseshoe bat Rhinolophus clivosus sensu lato with specific emphasis on the southern African representatives which, although not currently recognized, were previously described as a separate species R. geoffroyi comprising four subspecies. Sequence divergence estimates of the mtDNA control region show that the southern African representatives of R. clivosus s.l. are as distinct from samples further north in Africa than they are from R. ferrumequinum, the sister-species to R. clivosus. Within South Africa, five genetically supported geographic groups exist and these groups are corroborated by echolocation and wing morphology data. The groups loosely correspond to the distributions of the previously defined subspecies and Maxent modelling shows a strong correlation between the detected groups and ecoregions. Based on molecular clock calibrations, it is evident that climatic cycling and related vegetation changes during the Quaternary may have facilitated diversification both genetically and ecologically.

  4. Interannual to interdecadal variability of winter and summer southern African rainfall, and their teleconnections

    Science.gov (United States)

    Dieppois, Bastien; Pohl, Benjamin; Rouault, Mathieu; New, Mark; Lawler, Damian; Keenlyside, Noel

    2016-06-01

    This study examines for the first time the changing characteristics of summer and winter southern African rainfall and their teleconnections with large-scale climate through the dominant time scales of variability. As determined by wavelet analysis, the austral summer and winter rainfall indices exhibit three significant time scales of variability over the twentieth century: interdecadal (15-28 years), quasi-decadal (8-13 years), and interannual (2-8 years). Teleconnections with global sea surface temperature and atmospheric circulation anomalies are established here but are different for each time scale. Tropical/subtropical teleconnections emerge as the main driver of austral summer rainfall variability. Thus, shifts in the Walker circulation are linked to the El Niño-Southern Oscillation (ENSO) and, at decadal time scales, to decadal ENSO-like patterns related to the Pacific Decadal Oscillation and the Interdecadal Pacific Oscillation. These global changes in the upper zonal circulation interact with asymmetric ocean-atmospheric conditions between the South Atlantic and South Indian Oceans; together, these lead to a shift in the South Indian Convergence Zone and a modulation of the development of convective rain-bearing systems over southern Africa in summer. Such regional changes, embedded in quasi-annular geopotential patterns, consist of easterly moisture fluxes from the South Indian High, which dominate southerly moisture fluxes from the South Atlantic High. Austral winter rainfall variability is more influenced by midlatitude atmospheric variability, in particular the Southern Annular Mode. The rainfall changes in the southwestern regions of southern Africa are determined by asymmetrical changes in the midlatitude westerlies between the Atlantic and Indian Oceans.

  5. Reconnaissance of the Pere Marquette River, a cold water river in the central part of Michigan's Southern Peninsula

    Science.gov (United States)

    Hendrickson, G.E.; Doonan, C.J.

    1971-01-01

    The cold-water streams of the northern states provide unique recreational values to the American people (wilderness or semi-wilderness atmosphere, fast-water canoeing, and trout fishing) but the expanding recreational needs must be balanced against the growing demand of water for public and industrial supplies, for irrigation, and for the dilution of sewage and other wastes. In order to make intelligent decisions regarding use and management of the water resource for recreation and other demands, an analysis of the hydrologic factors related to recreational values is essential.The Pere Marquette, an outstanding river for brown and steelhead trout fishing, is also a popular canoe trail. Larger boats, some equipped with motors, are common in the lower reaches where the river is wide and deep. Cabins are abundant on the river near Baldwin but are relatively sparse elsewhere. The broad swampy floodplain that borders most of the river between Walhalla and Ludington apparently offers few favorable cabin sites.The Pere Marquette is located in the west-central part of the Southern Peninsula of Michigan, and flows westward from the headwaters near Chase in Lake County to the mouth at Ludington, in Mason County. The river is south of, and roughly parallel to, U.S. Highway 10 from Chase to Ludington. Access to the river is by roads leading south from U.S. 10 at Nirvana, Idlewild, Baldwin, Branch, Walhalla, Scottville, and many intermediate points.The recreational value of the river depends on the streamflow characteristics, quality of water, and character of stream channel and bed and banks. The purpose of this report is to describe these characteristics and show how they relate to recreational USGS.Most of the information presented here was obtained from a field reconnaissance in July and August, 1966, and from basic records of the U.S. Geological Survey's Water Resources Division. The area of field study is limited to the channel, bed, and banks of the Middle Branch and

  6. Reconnaissance of the Pigeon River, a cold-water river in the north-central part of Michigan's southern peninsula

    Science.gov (United States)

    Hendrickson, G.E.; Doonan, C.J.

    1970-01-01

    The cold-water streams of the northern states provide unique recreational values to the American people (wilderness or semi-wilderness atmosphere, fast-water canoeing, and trout fishing), but the expanding recreational needs must be balanced against the growing demand of water for public and industrial supplies, for irrigation, and for the dilution of sewage and other wastes. In order to make intelligent decisions regarding use and management of the water resource for recreation and other demands, an analysis of the hydrologic factors related to recreational values is essential.The Pigeon River is one of Michigan's outstanding trout streams and is the favorite of a large number of anglers who return year after year. Camping is also popular and is usually, but not always, associated with fishing. Boating is very rare on the Pigeon because of numerous portages around log jams. Cabin-living and resorting are relatively minor on this river as yet, but much of the private river front may be developed in future years.The Pigeon is located in the north-central part of the southern peninsula of Michigan (see index map). Headwaters are a few miles northeast of Gaylord, and the mouth is at Mullet Lake, a few miles northeast of Indian River. Interstate Highway 75 roughly parallels the river about 5 to 10 miles to the west. Exits from this highway at Gaylord, Vanderbilt, Wolverine, and Indian River, provide easy access to the Pigeon.The recreational value of the river depends on the streamflow characteristics, quality of water, and character of stream channel, and bed and banks. The purpose of this atlas is to describe these characteristics, and to show how they relate to recreational uses.Most of the information presented here was obtained from a field reconnaissance in June, 1966, and from basic records of the U.S. Geological Survey's Water Resources Division. The area of field study is limited to the channel, bed, and banks of the main stem of the Pigeon from source to

  7. The Nubian Complex of Dhofar, Oman: an African middle stone age industry in Southern Arabia.

    Directory of Open Access Journals (Sweden)

    Jeffrey I Rose

    Full Text Available Despite the numerous studies proposing early human population expansions from Africa into Arabia during the Late Pleistocene, no archaeological sites have yet been discovered in Arabia that resemble a specific African industry, which would indicate demographic exchange across the Red Sea. Here we report the discovery of a buried site and more than 100 new surface scatters in the Dhofar region of Oman belonging to a regionally-specific African lithic industry--the late Nubian Complex--known previously only from the northeast and Horn of Africa during Marine Isotope Stage 5, ∼128,000 to 74,000 years ago. Two optically stimulated luminescence age estimates from the open-air site of Aybut Al Auwal in Oman place the Arabian Nubian Complex at ∼106,000 years ago, providing archaeological evidence for the presence of a distinct northeast African Middle Stone Age technocomplex in southern Arabia sometime in the first half of Marine Isotope Stage 5.

  8. The diagnosis and management of snakebite in dogs - a southern African perspective : review article

    Directory of Open Access Journals (Sweden)

    A.L. Leisewitz

    2004-06-01

    Full Text Available Cases of snakebite envenomation are frequently presented to veterinary practitioners in southernAfrica. Despite this, no published guidelines exist onhowthis medical emergency should be managed. Southern African snake venoms can be classified into 3 main types based on the main mechanism of venom action and clinical presentation. A polyvalent antivenom is manufactured in South Africa and contains antibodies against the most important southern African snake venoms. The cytotoxic venoms are represented mainly by the puff-adder (Bitis arietans, Mozambique spitting cobra (Naja mossabica, black-necked spitting cobra (Naja nigricollis (in the Western Cape and Namibia and the stiletto snake (Atractaspis bibronii. These venoms may cause dramatic local swelling, high morbidity and low mortality and infrequently require the use of antivenom for survival (the only cytotoxic venoms used to prepare the antivenom are the puff-adder and Mozambique spitting cobra. The neurotoxic venoms (represented chiefly by the non-spitting cobras and mambas cause high mortality due to rapid onset of paresis and require antivenom and mechanical ventilatory support which is life-saving. The boomslang (Dispholidus typus and the vine snake (coagulopathic venom rarely bite humans but dogs may be bitten more frequently. These venoms cause a consumption coagulopathy and successful treatment of boomslang bites requires the use of snake species-specific monovalent antivenom. There is no antivenom available for treating vine snake (Thelotornis capensis, berg adder (Bitis atropos, night adder (Causus spp., stiletto snake and other lesser adder bites. There are some important differences between the way snakebites are managed in humans and dogs.

  9. A taxonomic revision of the southern African native and naturalized species of Silene L. (Caryophyllaceae

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    J. C. Manning

    2012-12-01

    Full Text Available The native and naturalized species of Silene L. in southern Africa are reviewed, with full synonomy and the description of two new species from the West Coast of Western Cape. Eight native species and three naturalized species are recognized, including the first identification in southern Africa of the Mediterranean S. nocturna L. The identity of S. aethiopica Burm., which has remained unknown since its description, is established and is found to be the oldest name for S. clandestina Jacq. Patterns of morphological variation within each species are discussed and subspecies are recognized for geographically segregated groups of populations that are ± morphologically diagnosable. The following new names or combinations are made among the southern African taxa: S. aethiopica subsp. longiflora; S. burchellii subsp. modesta, subsp. multiflora, and subsp. pilosellifolia; S. crassifolia subsp. primuliflora; S. saldanhensis; S. rigens; and S. undulata subsp. polyantha. Each taxon is described, with information on ecology and distribution, and most species are illustrated, including SEM micrographs of the seeds.

  10. Decadal variability of summer southern African rainfall variability, and their teleconnections in the CMIP5 models

    Science.gov (United States)

    Dieppois, B.; Pohl, B.; Crétat, J.; Rouault, M.; Keenlyside, N.; New, M. G.; Lawler, D.

    2016-12-01

    This study examines for the first time the ability of 24 global climate models from the Coupled Model Intercomparison Project 5 (CMIP5) to reproduce decadal timescales of summer southern African rainfall variability and their teleconnections with large-scale climate through the dominant time scales of variability. As determined by wavelet analysis, the observed austral summer and rainfall indices exhibit three significant time scales of variability over the twentieth century: interdecadal (15-28 years), quasi-decadal (8-13 years), and interannual (2-8 years). Decadal timescales of variability are strongly underestimated in all CMIP5 models, and this can be due to misrepresentation of large-scale climate teleconnections. Tropical/subtropical teleconnections emerge as the main driver of austral summer rainfall variability in the observations. Thus, shifts in the Walker circulation are linked to decadal ENSO-like patterns, such as the Pacific Decadal Oscillation and the Interdecadal Pacific Oscillation. These global changes in the upper zonal circulation interact with asymmetric ocean-atmospheric conditions between the South Atlantic and South Indian Oceans; together, these lead to a shift in the South Indian Convergence Zone and a modulation of the development of convective rain-bearing systems over southern Africa in summer. Interdecadal and quasidecadal SST anomalies correctly simulated in all the CMIP5 models, in particular in the Pacific. This leads to regional biases in the CMIP5 models in simulating the atmospheric circulation over southern Africa.

  11. The Southern African Centre for infectious disease surveillance: a one health consortium.

    Science.gov (United States)

    Rweyemamu, Mark M; Mmbuji, Peter; Karimuribo, Esron; Paweska, Janusz; Kambarage, Dominic; Neves, Luis; Kayembe, Jean-Marie; Mweene, Aaron; Matee, Mecky

    2013-01-01

    Formed in 2008, the Southern African Centre for Infectious Disease Surveillance (SACIDS) is a One Health consortium of academic and research institutions involved with infectious diseases of humans and animals. Operating in partnership with world-renowned centres of research in industrialised countries, its mission is to harness innovations in science and technology for improving southern Africa's capacity to detect, identify, monitor (DIM) and manage the risk posed by infectious diseases of humans, animals, and ecosystems. The consortium's major capacity development activities include a series of One Health-based Master of Science (MSc) courses and a five-year DIM-driven research program. Additionally, SACIDS organized Africa's first One Health conference, in July 2011. This paper describes these and other major activities that SACIDS has undertaken to improve infectious disease surveillance across southern Africa. The paper also describes the role and collaboration of SACIDS with other national, regional and international consortia/networks that share a vision and interest in promoting novel approaches to infectious disease surveillance and outbreak response.

  12. Vertical slip rates of active faults of southern Albania inferred from river terraces

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    Oswaldo Guzmán

    2014-02-01

    Full Text Available Fluvial terraces of Shkumbin, Devoll, Osum and Vjosa rivers (southern Albania and northwestern Greece are studied in order to quantify the vertical slip rates of the large active faults of the Dinaric-Albanic-Hellenic Alpine fold belt. The spatial and temporal variations of the incision rates along these rivers were estimated from the geomorphological mapping of the Quaternary sediments, the geometry and the dating of the terraces. Eleven terraces levels were identified in Albania from 68 geochronological ages already published or acquired for this work. The five lower terraces of the four studied rivers are well dated (10 new and 23 already published ages. These terraces are younger than 30 ka and their remnants are numerous. Their restoration allows estimating the regional trend of incision rate and the identification of local shifts. We argue that these shifts are linked to the active tectonics when they coincide with the faults already mapped by previous authors. Vertical slip rates for eight active faults in southern Albania are thus estimated for the last 19 ka and vary from ~0.1 to ~2 mm/a. The Lushnje Tepelene Thrust, that extends more than 120 kilometers, has a throw rate that varies from 0.2 to 0.8 mm/a, whereas the active faults of the extensional domain are segmented but are very active, with throw rates reaching locally 2 mm/a.

  13. On the stationarity of Floods in west African rivers

    Science.gov (United States)

    NKA, B. N.; Oudin, L.; Karambiri, H.; Ribstein, P.; Paturel, J. E.

    2014-12-01

    West Africa undergoes a big change since the years 1970-1990, characterized by very low precipitation amounts, leading to low stream flows in river basins, except in the Sahelian region where the impact of human activities where pointed out to justify the substantial increase of floods in some catchments. More recently, studies showed an increase in the frequency of intense rainfall events, and according to observations made over the region, increase of flood events is also noticeable during the rainy season. Therefore, the assumption of stationarity on flood events is questionable and the reliability of flood evolution and climatic patterns is justified. In this work, we analyzed the trends of floods events for several catchments in the Sahelian and Sudanian regions of Burkina Faso. We used thirteen tributaries of large river basins (Niger, Nakambe, Mouhoun, Comoé) for which daily rainfall and flow data were collected from national hydrological and meteorological services of the country. We used Mann-Kendall and Pettitt tests to detect trends and break points in the annual time series of 8 rainfall indices and the annual maximum discharge records. We compare the trends of precipitation indices and flood size records to analyze the possible causality link between floods size and rainfall pattern. We also analyze the stationary of the frequency of flood exceeding the ten year return period level. The samples were extracted by a Peak over threshold method and the quantification of change in flood frequency was assessed by using a test developed by Lang M. (1995). The results exhibit two principal behaviors. Generally speaking, no trend is detected on catchments annual maximum discharge, but positive break points are pointed out in a group of three right bank tributaries of the Niger river that are located in the sahelian region between 300mm to 650mm. These same catchments show as well an increase of the yearly number of flood greater than the ten year flood since

  14. Groundwater quality characterization to protect biodiversity in SADC region (Southern African Development Community

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    Stefania Vitale

    2016-06-01

    Full Text Available The following paper describes the first phase of a study held in the context of the SECOSUD Phase II project, called “Conservation and equitable use of biological diversity in the SADC region (Southern African Development Community, which aims at promoting biodiversity conservation and sustainable economic development in the SADC [1]. The Southern African Development Community (SADC is an inter-governmental organization, with 15 member states: Angola, Botswana, Democratic Republic of Congo, Lesotho, Mauritius, Malawi, Mozambique, Namibia, Madagascar, Seychelles, South Africa, Swaziland, Tanzania, Zambia, and Zimbabwe. Its aim is to increase socio-economic cooperation and integration among the community. It is one of the richest area in terms of biodiversity. The main goal of the Project is to contribute to stop biodiversity loss by supporting the development of conservation strategies. Biodiversity or biological diversity is formally defined by the Convention on Biological Diversity (CBD as: “the variability among living organisms from all sources including, among others, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems” (UN 1992 Article 2 [2]. Biodiversity is affected by the interaction of multiple drivers and pressures including demographic, economic, socio-political, scientific and technological ones, which are leading to further decline, degradation and loss. The principal pressures on biodiversity include habitat loss and degradation, overexploitation, alien invasive species, climate change and pollution. These pressures are continuing to increase. To use biodiversity and to keep it in a sustainable way, it is necessary to study it, assess its economic value, develop a global strategy and a global network to monitor its status in the biosphere. An important step in developing conservation of biodiversity

  15. Effects of repeated burning on woody vegetation structure and composition in a semi-arid southern African savanna

    NARCIS (Netherlands)

    Gandiwa, E.

    2011-01-01

    The objective of this study was to investigate the effects of repeated dry season annual hot fires on woody plants in a semiarid southern African savanna in Zimbabwe. Parts of the National University of Science and Technology (NUST) research fields in Bulawayo, Zimbabwe have been burnt annually in

  16. Mainstreaming biodiversity and wildlife management into climate change policy frameworks in selected east and southern African countries

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    Olga L. Kupika

    2016-03-01

    Full Text Available The Rio+20 outcomes document, the Future We Want, enshrines green economy as one of the platforms to attain sustainable development and calls for measures that seek to address climate change and biodiversity management. This paper audits climate change policies from selected east and southern African countries to determine the extent to which climate change legislation mainstreams biodiversity and wildlife management. A scan of international, continental, regional and national climate change policies was conducted to assess whether they include biodiversity and/or wildlife management issues. The key finding is that many climate change policy–related documents, particularly the National Adaptation Programme of Actions (NAPAs, address threats to biodiversity and wildlife resources. However, international policies like the United Nations Framework Convention on Climate Change and Kyoto Protocol do not address the matter under deliberation. Regional climate change policies such as the East African Community, Common Market for Eastern and Southern Africa and African Union address biodiversity and/or wildlife issues whilst the Southern African Development Community region does not have a stand-alone policy for climate change. Progressive countries like Rwanda, Uganda, Tanzania and Zambia have recently put in place detailed NAPAs which are mainstream responsive strategies intended to address climate change adaptation in the wildlife sector.Keywords: mainstreaming, biodiversity, wildlife, climate change policy, east and southern Africa

  17. Compiling an Evidence-Based Improvement Plan for the Support of Distance-Education Students at a Southern African University

    Science.gov (United States)

    Makhakhane, Bothephana; Wilkinson, Annette C.; Ndeya-Ndereya, Charity N.

    2016-01-01

    This article illustrates how an event guide can be used to organise, systematise and prioritise the large amount of findings from an extensive study. The study aimed to enhance student support at a distance-education institute in a Southern African country (Lesotho). In this case study an improvement-oriented evaluation of the strengths,…

  18. Reproductive system and the spermatophoric reaction of the mesopelagic squid Octopoteuthis sicula (Ruppell 1844) (Cephalopoda : Octopoteuthidae) from southern African waters

    NARCIS (Netherlands)

    Hoving, H. J. T.; Lipinski, M. R.; Videler, J. J.

    2008-01-01

    Reproductive features of the poorly known oceanic squid Octopoteuthis sicula are described and quantified to gain insight into the reproductive biology of the species. The data are based on 39 complete and partial specimens from southern African waters, collected between 1975 and 2005. The specimens

  19. Enhanced curriculum intervention did not result in increased postnatal physical activity in rural, Southern, primarily African American women

    Science.gov (United States)

    Purpose. To test the impact of two home visiting curricula on postnatal physical activity in rural, Southern, African American mothers. Design. Randomized controlled trial. Setting. Three rural counties in Mississippi. Subjects. Between September 2013 and May 2016, 54 postpartum women randomized...

  20. Towards an understanding and application of environmental flow requirements for human welfare in East African Rivers

    Science.gov (United States)

    McClain, Michael

    2013-04-01

    In semi-arid regions of Africa, rivers are of vital importance to humans for the many direct ecosystem services they provide and, in some cases, for their potential to irrigate and power larger-scale development. More than in most regions of the world, Africans still rely individually on rivers for domestic water, nutrition, and other materials contributing to their daily welfare. This has led to a uniquely African adaptation of the environmental flow concept to incorporate the basic water needs of people as well as ecosystems. The combined flow is referred to as the 'Reserve'. East Africa has seen comparatively little development of its water resources to-date, but ambitious initiatives are underway to increase water use in new large-scale irrigation schemes and hydropower projects. Consequently, a number of comprehensive environmental flow assessments and ecohydrological research activities have recently been carried out in the region. This presentation briefly reviews the initiatives underway across the region but focuses mainly on combined research and flow-setting efforts in the transboundary Mara River Basin of Kenya and Tanzania, home to more than 800,000 people and the region's most popular conservation areas, Masai-Mara National Reserve and Serengeti National Park. Since 2006 a team of scientists, in cooperation with water authorities and the World Wide Fund for Nature (WWF), has investigated the hydrology, hydraulics, biology, and human uses of the Mara River in order to make initial environmental flow (reserve) recommendations. The flow regime of the still largely unregulated Mara River, based on analyses or 20+ years of data from three gauging stations, is highly variable and perennial flow in the middle reaches is dependent on inflows from two tributaries draining the heavily deforested Mau Escarpment, one of Kenya's five water towers. Downstream flows are also seasonally influenced by inflows from ephemeral tributaries that drain degraded grazing

  1. Exploring southern African Plateau uplift with landscape evolution model inversion and erosion history data

    Science.gov (United States)

    Stanley, Jessica; Braun, Jean; Flowers, Rebecca; Guillocheau, François; Robin, Cécile; Baby, Guillaume

    2017-04-01

    The southern African plateau is a dominant feature of African topography but there is considerable debate about when and how it formed. Cretaceous kimberlite activity and the presence of a large low shear seismic velocity province (LLSVP) in the deep mantle below southern Africa have lead many to propose uplift related to mantle processes. Better constraints on the timing of uplift have the potential to constrain the nature of the LLSVP and the source of support for southern Africa's anomalous elevations. However, surface uplift is difficult to detect directly in the geologic record and the relationships between mantle-sourced uplift and erosion are not necessarily direct. Here, we use a landscape evolution model combined with data constraining the spatiotemporal erosion patterns across southern Africa to explore how topographic development and erosion are related. This is an ideal location to utilize this approach because several recent studies have helped to constrain the erosion history of this region over different spatial and temporal scales but the uplift history is still widely debated. We integrate a highly efficient landscape evolution model (FastScape, Braun and Willett, 2013) and a thermal module with a large low temperature thermochronology dataset, sedimentary flux volumes for the major offshore basins, and geologic observations to address these questions. We used inversion methods based on the Neighborhood Algorithm to investigate how data is best simulated by the model while varying model parameters related to plateau uplift and the physical characteristics of the eroding material. This is a powerful approach because we are able to compare model outputs to many aspects of topographic shape and constraints on the erosion history simultaneously. Results from the inversions show that the data are sufficient to constrain many model parameters. Additionally, we show that the combination of different types of data, and in particular the spatiotemporal

  2. River flow and inundation in African river systems: results from a new pan-African land-surface model validated against Earth observations

    Science.gov (United States)

    Dadson, Simon

    2015-04-01

    The role of surface-water flooding in controlling fluxes of water and carbon between the land and the atmosphere is increasingly recognized in studies of the Earth system. Simultaneous advances in remote earth observation and large-scale land-surface and hydrological modeling promise improvements in our ability to understand these linkages, and suggest that improvements in prediction of river flow and inundation extents may result. Here we present an analysis of newly-available observational estimates of surface water inundation obtained through satellite Earth observation with results from simulations produced by using the Joint UK Land Environment Simulator (JULES) land-surface model operating at 0.5 degree resolution over the African continent. The model was forced with meteorological input from the WATCH Forcing Data for the period 1981-2001 and sensitivity to various model configurations and parameter settings were tested. Both the PDM and TOPMODEL sub-grid scale runoff generation schemes were tested for parameter sensitivities, with the evaluation focussing on simulated river discharge in sub-catchments of the Congo, Nile, Niger, Orange, Okavango and Zambezi rivers. It was found that whilst the water balance in each of the catchments can be simulated with acceptable accuracy, the individual responses of each river vary between model configurations so that there is no single runoff parameterization scheme or parameter values that yields optimal results across all catchments. We trace these differences to the model's representation of sub-surface flow and make some suggestions to improve the performance of large-scale land-surface models for use in similar applications. These findings suggest that the use of Earth observation data together with improved models of large-scale hydrology have the potential to improve our ability to predict surface-water flooding and to develop our understanding of the role of flooding in driving components of the water and carbon

  3. Epizootic ulcerative syndrome affecting fish in the Zambezi river system in southern Africa.

    Science.gov (United States)

    Andrew, T G; Huchzermeyer, K D A; Mbeha, B C; Nengu, S M

    2008-11-22

    In late 2006, diseased fish of a variety of species began to appear in the Chobe and upper Zambezi rivers in southern Africa. In April 2007, investigations showed that the levels of pesticides and heavy metals in the tissues of the fish were very low, discounting pollution as an underlying cause for the disease. However, histological evidence showed that the disease closely resembled the epizootic ulcerative syndrome caused by the oomycete Aphanomyces invadans, a serious aquatic pathogen that has been isolated from freshwater and estuarine fish in Japan, south-east Asia, Australia and the usa since the 1970s, but not previously recorded in Africa.

  4. Radiation risk and cancer mortality in exposed populations living near the Techa River in Southern Urals

    Energy Technology Data Exchange (ETDEWEB)

    Kossenko, M.M.; Degteva, M.O.

    1992-06-01

    The appropriateness of applying risk coefficients calculated from short-term exposures at high doses for the assessment of radiation effects at low doses is currently much debated. The problem can be resolved on the basis of the data obtained from a long-term follow-up of the population exposed in the early 1950s when discharges of radioactive wastes from a radiochemical plant into the Techa River (southern Urals) occurred. This paper discusses the results of an analysis of cancer mortality during the period 1950-82. 10 refs., 5 figs., 8 tabs.

  5. Trace-metal contamination of the African giant land snail Archachatina marginata from Southern Nigeria.

    Science.gov (United States)

    Wegwu, Matthew O; Wigwe, Ihundah A

    2006-01-01

    The levels of bio-accumulated trace metals in the African giant land snail Archachatina marginata, collected in six different states of Southern Nigeria, were determined. The Cu and Fe levels were 3.0-9.8 and 12.4-35.2 mg/kg body weight, respectively (Table). Similarly, the concentrations of Zn, Ni, Pb, and Cd were 10.3-20.5, 3.20-10.4, 0.80-6.00, and 0.60-0.84 mg/kg, respectively. Although the trace-metal levels for some samples collected in highly industrialized zones approached or even considerably exceeded the upper WHO limits, the average concentrations of trace metals recorded in this study remained below critical values.

  6. A qualitative ecological risk assessment of the invasive Nile tilapia, Oreochromis niloticus in a sub-tropical African river system (Limpopo River, South Africa)

    CSIR Research Space (South Africa)

    Zengeya, TA

    2013-01-01

    Full Text Available CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS Aquatic Conserv: Mar. Freshw. Ecosyst. 23: 51–64 (2013) A QUALITATIVE ECOLOGICAL RISK ASSESSMENT OF THE INVASIVE NILE TILAPIA, OREOCHROMIS NILOTICUS IN A SUB- TROPICAL AFRICAN RIVER SYSTEM (LIMPOPO RIVER... Hatfield, Pretoria, 0028 South Africa b Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown, 6140 South Africa c Natural Resources and the Environment Council for Scientific and Industrial Research (CSIR), PO Box...

  7. Comparing spatial patterns of thrust belt architecture and bedrock river morphology across the southern Bolivian Andes

    Science.gov (United States)

    Syrek, J. F.; Barnes, J. B.

    2011-12-01

    Rivers set the pace of mountain landscape evolution, but their ability to incise into rock is often governed by numerous factors. The degree to which variations in lithology, relief, rock uplift rates, and climate may affect the form of channel profiles remain largely open questions. Empirical models of bedrock river incision, such as stream power (E = KAmSn), oversimplify these potentially important factors. For example, the influence of many factors such as channel geometry, hydraulic roughness, sediment flux, and substrate erodibility are combined into the coefficient of erosion, K. Here we investigate the spatial patterns of rock erodibility, bedrock river slope, concavity, and stream power-based estimates of incision across the southern Bolivian Andes. We hypothesize that bedrock river morphology correlates with the thrust-belt geology. For example, channels cutting through the strongest and least fractured rock units will exhibit the highest steepness values. We estimate rock erodibility by measuring (a) compressive rock strength with a Schmidt hammer and (b) fracture density from exposures proximal to river channels at ~80 total sites from all the major rock units exposed throughout the study area. We use a hydrologically-conditioned 90 m digital elevation model to map patterns of channel steepness (ksn) and concavity (θ) indices. Furthermore, we use the stream power model, combined with a previous local calibration of K, to estimate patterns of river incision along the study area rivers. The combined strength and fracture density measurements suggest the Neogene volcanics, Cretaceous sediments, and Devonian metasediments are the least erodible units and the Silurian and Ordovician metasediments are the weakest. In general, changes in channel steepness often correlate with (1) changes in rock erodibility, (2) high rock uplift rates associated with active structures in the Subandes, and (3) the major hinterland structural transition between the Eastern

  8. Low densities of drifting litter in the African sector of the Southern Ocean.

    Science.gov (United States)

    Ryan, Peter G; Musker, Seth; Rink, Ariella

    2014-12-15

    Only 52 litter items (>1cm diameter) were observed in 10,467 km of at-sea transects in the African sector of the Southern Ocean. Litter density north of the Subtropical Front (0.58 items km(-2)) was less than in the adjacent South Atlantic Ocean (1-6 items km(-2)), but has increased compared to the mid-1980s. Litter density south of the Subtropical Front was an order of magnitude less than in temperate waters (0.032 items km(-2)). There was no difference in litter density between sub-Antarctic and Antarctic waters either side of the Antarctic Polar Front. Most litter was made of plastic (96%). Fishery-related debris comprised a greater proportion of litter south of the Subtropical Front (33%) than in temperate waters (13%), where packaging dominated litter items (68%). The results confirm that the Southern Ocean is the least polluted ocean in terms of drifting debris and suggest that most debris comes from local sources. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. IDESSA: An Integrative Decision Support System for Sustainable Rangeland Management in Southern African Savannas

    Science.gov (United States)

    Meyer, Hanna; Authmann, Christian; Dreber, Niels; Hess, Bastian; Kellner, Klaus; Morgenthal, Theunis; Nauss, Thomas; Seeger, Bernhard; Tsvuura, Zivanai; Wiegand, Kerstin

    2017-04-01

    Bush encroachment is a syndrome of land degradation that occurs in many savannas including those of southern Africa. The increase in density, cover or biomass of woody vegetation often has negative effects on a range of ecosystem functions and services, which are hardly reversible. However, despite its importance, neither the causes of bush encroachment, nor the consequences of different resource management strategies to combat or mitigate related shifts in savanna states are fully understood. The project "IDESSA" (An Integrative Decision Support System for Sustainable Rangeland Management in Southern African Savannas) aims to improve the understanding of the complex interplays between land use, climate patterns and vegetation dynamics and to implement an integrative monitoring and decision-support system for the sustainable management of different savanna types. For this purpose, IDESSA follows an innovative approach that integrates local knowledge, botanical surveys, remote-sensing and machine-learning based time-series of atmospheric and land-cover dynamics, spatially explicit simulation modeling and analytical database management. The integration of the heterogeneous data will be implemented in a user oriented database infrastructure and scientific workflow system. Accessible via web-based interfaces, this database and analysis system will allow scientists to manage and analyze monitoring data and scenario computations, as well as allow stakeholders (e. g. land users, policy makers) to retrieve current ecosystem information and seasonal outlooks. We present the concept of the project and show preliminary results of the realization steps towards the integrative savanna management and decision-support system.

  10. Variations in Reading Achievement Across 14 Southern African School Systems: Which Factors Matter?

    Science.gov (United States)

    Hungi, Njora; Thuku, Florence W.

    2010-02-01

    In this study the authors employed a multilevel analysis procedure in order to examine the pupil and school levels factors that contributed to variation in reading achievement among Grade 6 primary school pupils in 14 southern African school systems (Botswana, Kenya, Lesotho, Malawi, Mauritius, Mozambique, Namibia, Seychelles, South Africa, Swaziland, Tanzania, Uganda, Zambia, and Zanzibar). The data for this study were collected in 2002 as part of a major project known as the Southern and Eastern Africa Consortium for Monitoring Educational Quality (SACMEQ) that sought to examine the quality of education offered in primary schools in these countries. The most important factors affecting variation in pupil achievement across most of these school systems were grade repetition, pupil socioeconomic background, speaking the language of instruction at home, and Pupil age. South Africa, Uganda and Namibia were among the school systems with the largest between-school variation while Seychelles and Mauritius had the largest within-school variation. Low social equity in reading achievement was evident in Mauritius, Seychelles and Tanzania. Policy implications of the findings are discussed.

  11. Pollen morphology of members of southern African Boerhavia and Commicarpus (Nyctaginaceae

    Directory of Open Access Journals (Sweden)

    M. Struwig

    2013-01-01

    Full Text Available In southern Africa, Boerhavia L. and Commicarpus Standl. are the most species-rich genera of the Nyctaginaceae. Hitherto, the pollen morphology of only three southern African species of each of these genera has been described. A palynological study of the remaining species is therefore necessary to complete the information for the taxa. The pollen morphology of sixteen species was studied with light, scanning electron and transmission electron microscopy. Pollen grains of Boerhavia and Commicarpus are uniform in shape and sculpturing. Grains are spheroidal and pantoporate, and the tectum tubuliferous and spinulose. Pollen grains of the Boerhavia are 52–91 μm in diameter and those of Commicarpus 52–129 μm. Spinules in both genera are 1–5 μm long. Pore plates have one or two spinules. In both genera the exine is 3.5–11.5 μm thick, the tectum 0.9–3.9 μm thick and the collumellae 0.6–2.8 μm long. Foot layers are 0.9–5.1 μm thick and the endexine is barely visible. Size variation of the pollen grain, pore diameter and exine thickness overlap and cannot be used to distinguish between the two genera or the individual species.

  12. Implementing the millennium development food security goals Challenges of the southern African context

    Science.gov (United States)

    Love, David; Twomlow, Steve; Mupangwa, Walter; van der Zaag, Pieter; Gumbo, Bekithemba

    The Millennium Development Goals’ target to halve the proportion of people who suffer from hunger is extremely important in southern Africa, where food security has become increasingly problematic over the last 20 years. One “quick-win” proposal is replenishment of soil nutrients for smallholder farmers, through free or subsidised chemical fertilisers. Other proposals include appropriate irrigation technology, improved inputs and interventions targeted at women. Analysis of over 10 years of agro-hydrological and agro-economic studies from southern African show that a different approach is required to interventions proposed. There are sustainability problems with free chemical fertiliser due to transport costs and ancillary costs. Furthermore, recent studies in Zimbabwe and Mozambique show that significant increases in yield can only be obtained when soil fertility management is combined with good crop husbandry, e.g. timely planting and weeding. Ongoing replenishment of fertility would be dependent on a continued free or subsidised fertiliser supply, and transport system. Increasing access to irrigation will help, but is not the only solution and cannot reach even a majority of farmers. It has been determined that short dryspells are often the major cause of low yields in sub-Saharan Africa. Soil-water conservation approaches, e.g. winter weeding and conservation tillage, can reduce risk and increase yield. The following specific recommendations are made for urgent interventions to contribute sustainably to food security in southern Africa: (i) To increases access to fertiliser, consider development of strong input markets at end-user level. (ii) Intensification of technology transfer, focusing on capacity building for transfer of existing technologies and much closer collaboration between state and NGO sectors, agronomists and water engineers. (iii) Increasing the uptake of soil-water conservation methods, including conservation tillage and weeding, and

  13. Modeling of soil erosion and sediment transport in the East River Basin in southern China

    Science.gov (United States)

    Wu, Yping; Chen, Ji

    2012-01-01

    Soil erosion is a major global environmental problem that has caused many issues involving land degradation, sedimentation of waterways, ecological degradation, and nonpoint source pollution. Therefore, it is significant to understand the processes of soil erosion and sediment transport along rivers, and this can help identify the erosion prone areas and find potential measures to alleviate the environmental effects. In this study, we investigated soil erosion and identified the most seriously eroded areas in the East River Basin in southern China using a physically-based model, Soil and Water Assessment Tool (SWAT). We also introduced a classical sediment transport method (Zhang) into SWAT and compared it with the built-in Bagnold method in simulating sediment transport process along the river. The derived spatial soil erosion map and land use based erosion levels can explicitly illustrate the identification and prioritization of the critical soil erosion areas in this basin. Our results also indicate that erosion is quite sensitive to soil properties and slope. Comparison of Bagnold and Zhang methods shows that the latter can give an overall better performance especially in tracking the peak and low sediment concentrations along the river. We also found that the East River is mainly characterized by sediment deposition in most of the segments and at most times of a year. Overall, the results presented in this paper can provide decision support for watershed managers about where the best management practices (conservation measures) can be implemented effectively and at low cost. The methods we used in this study can also be of interest in sediment modeling for other basins worldwide.

  14. Recent, climate-driven river incision rate fluctuations in the Mercantour crystalline massif, southern French Alps

    Science.gov (United States)

    Petit, C.; Goren, L.; Rolland, Y.; Bourlès, D.; Braucher, R.; Saillard, M.; Cassol, D.

    2017-06-01

    We present a new geomorphological analysis of the Tinée River tributaries in the southern French Alps based on numerical inverse and forward modelling of their longitudinal profiles. We model their relative uplift history with respect to the main channel, hence the incision rate history of this channel. Inverse models show that all tributaries have consistent incision rate histories with alternating high and low values. A comparison with global temperature curves shows that these variations correlate with quaternary climate changes. We suggest that during warm periods, a wave of regressive erosion propagates in the Tinée River, while its tributaries deeply incise their substratum to catch up with the falling base-level. We also show that the post 140 ka history of this landscape evolution is dominated by fluvial incision. We then perform forward models of river incision and simulate the incision of the Tinée River system over a time span of 600 ka. This model allows us to extract time and space incision rate variations of the Tinée River. With a background of a few mm.yr-1, incision rate can increase up to more than 1 cm yr-1 during short periods of time due to climatic oscillations. This result is compatible with published cosmogenic nuclide based dating, which evidenced incision rates from 0.2 to 24 mm yr-1. The part of the channel located between 12 and 20 km downstream from the source has undergone several periods of rapid incision rates, which could explain the steep hillslopes and the triggering of a landslide ∼10 ka ago.

  15. Incision rate changes in the upper Var River catchment, southern French Alps: from observations to models.

    Science.gov (United States)

    Petit, Carole; Rolland, Yann; Goren, Liran; Bourlès, Didier; Braucher, Régis; Saillard, Marianne; Cassol, Davide

    2017-04-01

    Cosmic Ray Exposure (CRE) dating on river polished surfaces from gorges located in the Var River catchment (Southern French Alps) reveals high incision rate pulses (>10 mm.yr-1) related with climate changes, and in particular with glacial-interglacial transitions. In addition, they show that the onset of the last deglaciation in this area occurred shortly after the Last Glacial Maximum (LGM), i.e. 16-19 ka ago. Extrapolating these results to longer time scales suggests that the post 140 ka history of this landscape was dominated by fluvial incision. Inverse models based on the stream power law are then used to determine uplift rate variations in several small tributaries of this catchment with respect to the main channel. These inverse models show that all tributaries have consistent incision rate histories with alternating high and low values, and a comparison with global temperature curves shows that these variations significantly correlate with quaternary climate changes. We suggest that during warm periods, a wave of regressive erosion propagates in the main channel, while its tributaries deeply incise their substratum to catch up with the falling base-level. We then perform forward models of river incision and simulate the incision of the main channel system over a time span of 600 ka. This model allows us to extract time and space incision rate variations along the Tinée River channel (the largest tributary of the Var River). With a background of a few mm.yr-1, incision rate can increase up to more than 10 mm.yr-1 during short episodes, in agreement with CRE dating. The part of the channel located between 12 and 20 km downstream from the source has undergone several periods of rapid incision rates, which could explain the steep hillslopes and the triggering of a landslide 10 kyr ago.

  16. Paleomagnetic correlation of ignimbrites along the southern margin of the central Snake River Plain, Yellowstone hotspot

    Science.gov (United States)

    Finn, D. R.; Coe, R. S.; Spinardi, F.; Reichow, M. K.; Knott, T.; McDonnell, L.; Cunningham, D.; Branney, M.

    2011-12-01

    Mid-late Miocene explosive volcanism associated with the Yellowstone hotspot occurred in the central Snake River Plain, for example at the 12.5-11.3 Ma Bruneau-Jarbidge and 10-8.6 Ma Twin Falls eruptive centres. The volcanism was characterized by high-temperature rhyolitic caldera-forming super-eruptions, some exceeding 450 km3. To determine the number and scales and of these giant eruptions we are investigating successions of outflow ignimbrites at the southern and northern margins of the plain. The ignimbrites are exposed discontinuously in widely spaced (50-200 km) mountain ranges and are typically extensive, intensely welded and rheomorphic. Paleomagnetic characterization of individual (paleosol-bounded) eruption-units together with field, petrographic and chemical characterization will aid in stratigraphic correlation between distant sections. By correlating and mapping the eruption-units we can better estimate how the frequencies and volumes of the super-eruptions changed during eastward progression of Yellowstone hotspot volcanism. This information helps distinguish between effects of thermal flux, crustal structure, and tectonics on magmatic history of this continental large igneous province. Additionally, large caldera collapse events dramatically modify landscapes, and location and scale of calderas may have significantly contributed to Snake River Plain topography. Over 300 paleomagnetic cores were collected in September 2010 from the Cassia Hills, Rogerson Graben, and Bruneau-Jarbidge regions in the southern margin of the Snake River Plain. We drilled 10 oriented cores per eruption unit at reference sections from each location and demagnetized them with alternating-field (AF) and thermal demagnetization techniques. In some cases AF treatment up to 200 mT was unable to completely destroy a specimen's natural remnant magnetization and so thermal treatment was used to finish the experiment. Zjiderveld diagrams from AF, thermal and hybrid experiments show

  17. Reconnaissance of the Sturgeon River, a cold-water river in the north-central part of Michigan's southern peninsula

    Science.gov (United States)

    Hendrickson, G.E.; Doonan, C.J.

    1971-01-01

    The cold-water streams of the northern states provide unique recreational values to the American people (wilderness or semi-wilderness atmosphere, fast-water canoeing, trout fishing), but the expanding recreational needs must be balanced against the growing demand of water for public and industrial supplies, for irrigation, and for the dilution of sewage and other wastes. In order to make intelligent decisions regarding use and management of the water resources for recreation and other demands, analysis of the hydrologic factors related to recreational values is essential.The Sturgeon River north of Gaylord, one of the best brown trout streams in Michigan, is located in the north-central part of the southern peninsula of Michigan with headwaters just north of Gaylord. The Sturgeon flows northward, generally paralleling Interstate Highway 75. The West Branch of the Sturgeon, which joins the main stem at Wolverine, was not included in this study. Exits from Interstate 75 at Gaylord, Vanderbilt, Wolverine, and Indian River provide easy access to the Sturgeon. The recreational value of a river depends on the hydrologic characteristics of the river-the streamflow, water quality, and character of bed and banks. The purpose of this atlas is to describe these characteristics and to show how they relate to recreational uses. Much of the information presented here was derived from basic records of the U.S. Geological Survey's Water Resources Division. Additional information was obtained in a reconnaissance survey in May and June, 1966. The area of field study is limited to the channel, bed, and banks of the main stem from source to mouth. The study was made in cooperation with the Michigan Geological Survey, Gerald E. Eddy, Chief. Advice and assistance were also obtained from other sections of the Michigan Conservation Department. Sheet 1 of this atlas presents information on streamflow characteristics and water quality. Sheet 2 describes the physical characteristics of the

  18. African Models for Transnational River Basin Organisations in Africa: An Unexplored Dimension

    Directory of Open Access Journals (Sweden)

    Douglas J. Merrey

    2009-06-01

    Full Text Available One of the many legacies of colonialism in Africa is the multiplicity of river basins shared by two or more – and often far more – countries. Since changing national boundaries is not an option, African governments have no choice but to develop transnational institutions for developing shared water resources. Therefore, one finds a plethora of bilateral and multilateral committees, commissions, and authorities intended to facilitate agreements for infrastructural investments, management of water flows (quantity and quality, and response to disasters, especially floods. These efforts are supported by – indeed often, at least behind the scenes, driven by – western and international development partners. With few exceptions, the results to date are not impressive, as governments drag their feet on ratifying or implementing agreements and investing in creating the necessary institutional infrastructure, and donors’ funds go unspent because such agreements are conditions precedent for investment. Despite the work done by many international and local non-government organisations (NGOs as well as some governments, hardly any of the residents of African river basins are aware of these commissions. All of them are based on organisational models derived from western experiences and governing principles and are created by inter-governmental agreements. The citizens residing in the basin are rarely consulted. In some cases, powerful national hydraulic bureaucracies seek to control the process in an effort to gain leverage over infrastructural investments. There is a body of literature seeking to explain the ineffectiveness of transnational river basin management to date, largely based on political science, sociology and economics. Some but not all observers are concerned with the degree of democracy in the political process. This paper addresses a dimension that has received very little attention and therefore complements the existing literature

  19. African humid periods triggered the reactivation of a large river system in Western Sahara.

    Science.gov (United States)

    Skonieczny, C; Paillou, P; Bory, A; Bayon, G; Biscara, L; Crosta, X; Eynaud, F; Malaizé, B; Revel, M; Aleman, N; Barusseau, J-P; Vernet, R; Lopez, S; Grousset, F

    2015-11-10

    The Sahara experienced several humid episodes during the late Quaternary, associated with the development of vast fluvial networks and enhanced freshwater delivery to the surrounding ocean margins. In particular, marine sediment records off Western Sahara indicate deposition of river-borne material at those times, implying sustained fluvial discharges along the West African margin. Today, however, no major river exists in this area; therefore, the origin of these sediments remains unclear. Here, using orbital radar satellite imagery, we present geomorphological data that reveal the existence of a large buried paleodrainage network on the Mauritanian coast. On the basis of evidence from the literature, we propose that reactivation of this major paleoriver during past humid periods contributed to the delivery of sediments to the Tropical Atlantic margin. This finding provides new insights for the interpretation of terrigenous sediment records off Western Africa, with important implications for our understanding of the paleohydrological history of the Sahara.

  20. Towards One Health disease surveillance: The Southern African Centre for Infectious Disease Surveillance approach

    Directory of Open Access Journals (Sweden)

    Esron D. Karimuribo

    2012-06-01

    Full Text Available Africa has the highest burden of infectious diseases in the world and yet the least capacity for its risk management. It has therefore become increasingly important to search for ‘fit-for- purpose’ approaches to infectious disease surveillance and thereby targeted disease control. The fact that the majority of human infectious diseases are originally of animal origin means we have to consider One Health (OH approaches which require inter-sectoral collaboration for custom-made infectious disease surveillance in the endemic settings of Africa. A baseline survey was conducted to assess the current status and performance of human and animal health surveillance systems and subsequently a strategy towards OH surveillance system was developed. The strategy focused on assessing the combination of participatory epidemiological approaches and the deployment of mobile technologies to enhance the effectiveness of disease alerts and surveillance at the point of occurrence, which often lies in remote areas. We selected three study sites, namely the Ngorongoro, Kagera River basin and Zambezi River basin ecosystems. We have piloted and introduced the next-generation Android mobile phones running the EpiCollect application developed by Imperial College to aid geo-spatial and clinical data capture and transmission of this data from the field to the remote Information Technology (IT servers at the research hubs for storage, analysis, feedback and reporting. We expect that the combination of participatory epidemiology and technology will significantly improve OH disease surveillance in southern Africa.

  1. Towards one health disease surveillance: the Southern African Centre for Infectious Disease Surveillance approach.

    Science.gov (United States)

    Karimuribo, Esron D; Sayalel, Kuya; Beda, Eric; Short, Nick; Wambura, Philemon; Mboera, Leonard G; Kusiluka, Lughano J M; Rweyemamu, Mark M

    2012-06-20

    Africa has the highest burden of infectious diseases in the world and yet the least capacity for its risk management. It has therefore become increasingly important to search for 'fit-for- purpose' approaches to infectious disease surveillance and thereby targeted disease control. The fact that the majority of human infectious diseases are originally of animal origin means we have to consider One Health (OH) approaches which require inter-sectoral collaboration for custom-made infectious disease surveillance in the endemic settings of Africa. A baseline survey was conducted to assess the current status and performance of human and animal health surveillance systems and subsequently a strategy towards OH surveillance system was developed. The strategy focused on assessing the combination of participatory epidemiological approaches and the deployment of mobile technologies to enhance the effectiveness of disease alerts and surveillance at the point of occurrence, which often lies in remote areas. We selected three study sites, namely the Ngorongoro, Kagera River basin and Zambezi River basin ecosystems. We have piloted and introduced the next-generation Android mobile phones running the EpiCollect application developed by Imperial College to aid geo-spatial and clinical data capture and transmission of this data from the field to the remote Information Technology (IT) servers at the research hubs for storage, analysis, feedback and reporting. We expect that the combination of participatory epidemiology and technology will significantly improve OH disease surveillance in southern Africa.

  2. Estimating δ15N fractionation and adjusting the lipid correction equation using Southern African freshwater fishes.

    Directory of Open Access Journals (Sweden)

    Geraldine C Taylor

    Full Text Available Stable isotope analysis is an important tool for characterising food web structure; however, interpretation of isotope data can often be flawed. For instance, lipid normalisation and trophic fractionation values are often assumed to be constant, but can vary considerably between ecosystems, species and tissues. Here, previously determined lipid normalisation equations and trophic fractionation values were re-evaluated using freshwater fish species from three rivers in the Upper Zambezian floodplain ecoregion in southern Africa. The parameters commonly used in lipid normalisation equations were not correct for the 18 model species (new D and I parameters were estimated as D = 4.46‰ [95% CI: 2.62, 4.85] and constant I = 0 [95% CI: 0, 0.17]. We suggest that future isotopic analyses on freshwater fishes use our new values if the species under consideration do not have a high lipid content in their white muscle tissue. Nitrogen fractionation values varied between species and river basin; however, the average value closely matched that calculated in previous studies on other species (δ15N fractionation factor of 3.37 ± 1.30 ‰. Here we have highlighted the need to treat stable isotope data correctly in food web studies to avoid misinterpretation of the data.

  3. Fishes of the Taquari-Antas river basin (Patos Lagoon basin), southern Brazil.

    Science.gov (United States)

    Becker, F G; De Fries, L C C; Ferrer, J; Bertaco, V A; Luz-Agostinho, K D G; Silva, J F P; Cardoso, A R; Lucena, Z M S; Lucena, C A S

    2013-02-01

    The aquatic habitats of the Taquari-Antas river basin (in the Patos Lagoon basin, southern Brazil) are under marked environmental transformation because of river damming for hydropower production. In order to provide an information baseline on the fish fauna of the Taquari-Antas basin, we provide a comprehensive survey of fish species based on primary and secondary data. We found 5,299 valid records of fish species in the basin, representing 119 species and 519 sampling sites. There are 13 non-native species, six of which are native to other Neotropical river basins. About 24% of the total native species are still lacking a taxonomic description at the species level. Three native long-distance migratory species were recorded (Leporinus obtusidens, Prochilodus lineatus, Salminus brasiliensis), as well as two potential mid-distance migrators (Parapimelodus nigribarbis and Pimelodus pintado). Although there is only one officially endangered species in the basin (S. brasiliensis), restricted range species (21.7% of total species) should be considered in conservation efforts.

  4. Fishes of the Taquari-Antas river basin (Patos Lagoon basin, southern Brazil

    Directory of Open Access Journals (Sweden)

    FG. Becker

    Full Text Available The aquatic habitats of the Taquari-Antas river basin (in the Patos Lagoon basin, southern Brazil are under marked environmental transformation because of river damming for hydropower production. In order to provide an information baseline on the fish fauna of the Taquari-Antas basin, we provide a comprehensive survey of fish species based on primary and secondary data. We found 5,299 valid records of fish species in the basin, representing 119 species and 519 sampling sites. There are 13 non-native species, six of which are native to other Neotropical river basins. About 24% of the total native species are still lacking a taxonomic description at the species level. Three native long-distance migratory species were recorded (Leporinus obtusidens, Prochilodus lineatus, Salminus brasiliensis, as well as two potential mid-distance migrators (Parapimelodus nigribarbis and Pimelodus pintado. Although there is only one officially endangered species in the basin (S. brasiliensis, restricted range species (21.7% of total species should be considered in conservation efforts.

  5. Niger River Discharge and the Connection to the West African Monsoon Over the Last 25 kyr

    Science.gov (United States)

    Patten, J.; Marcantonio, F.; Slowey, N. C.; Schmidt, M. W.; Parker, A. O.; Thomas, D. J.

    2016-12-01

    The intensity of the West African monsoon is directly tied to the shifting of the Inter-Tropical Convergence Zone and global-scale climate variability. As the West African monsoon varies through time, it affects the precipitation that occurs within the Niger River basin and the Niger River's discharge into the eastern equatorial Atlantic Ocean. The accumulation of marine sediments on the continental slope offshore of the Niger Delta reflects these processes. We seek to better understand how related environmental processes have varied as climate and sea level changed during the latter part of the last glacial-interglacial cycle. Here we present results from our ongoing investigation of sediments collected offshore of the Niger Delta that reflect such changes. The concentrations of 230Th, 232Th, and 234U in the sediments have been measured and combined with ages from radiocarbon dates and planktonic foraminiferal δ18O stratigraphies to estimate how the rate of sediment accumulation has varied through time. This record is considered together with measurements of sediment CaCO3 content and grain-size distribution to better understand the relative importance of environmental processes that control the flux of sediments and thorium to the seafloor - scavenging by particles settling through the water column versus the transport of sediments downslope by turbidity flows. We present xs230Th-derived 232Th fluxes that we suggest approximate the amount of fine-grained detrital material delivered from the Niger River to our sites. We anticipate that the importance of these competing processes will vary as climate/sea-level change influences the flux of sediments from the Niger River and the transport of these sediments to the slope.

  6. Petrocephalus boboto and Petrocephalus arnegardi, two new species of African electric fish (Osteoglossomorpha, Mormyridae) from the Congo River basin

    OpenAIRE

    Lavoué, Sébastien; Sullivan, John P.

    2014-01-01

    Abstract A specimen of the African weakly electric fish genus Petrocephalus (Osteoglossomorpha, Mormyridae) collected in the Congo River at Yangambi, Orientale Province, Democratic Republic of Congo, is described as a new species. Petrocephalus boboto sp. n. can be distinguished from other Central African species of Petrocephalus by a combination of the following characteristics: three distinct black spots on the body, one at the origin of the pectoral fin, one at the origin of the caudal fin...

  7. The fluvial sediment budget of a dammed river (upper Muga, southern Pyrenees)

    Science.gov (United States)

    Piqué, G.; Batalla, R. J.; López, R.; Sabater, S.

    2017-09-01

    Many rivers in the Mediterranean region are regulated for urban and agricultural purposes. Reservoir presence and operation results in flow alteration and sediment discontinuity, altering the longitudinal structure of the fluvial system. This study presents a 3-year sediment budget of a highly dammed Mediterranean river (the Muga, southern Pyrenees), which has experienced flow regulation since the 1969 owing to a 61-hm3 reservoir. Flow discharge and suspended sediment concentration were monitored immediately upstream and downstream from the reservoir, whereas bedload transport was estimated by means of bedload formulae and estimated from regional data. Results show how the dam modifies river flow, reducing the magnitude of floods and shortening its duration. At the same time, duration of low flows increases. The downstream flow regime follows reservoir releases that are mostly driven by the irrigation needs in the lowlands. Likewise, suspended sediment and bedload transport are shown to be notably affected by the dam. Sediment transport upstream was mainly associated with floods and was therefore concentrated in short periods of time (i.e., > 90% of the sediment load occurred in sediments were transported more constantly (i.e., 90% of the load was carried during 50% of the time). Total sediment load upstream from the dam equalled 23,074 t, while downstream it was sediment load was equally distributed between suspension and bedload (i.e., 10,278 and 12,796 t respectively), whereas suspension dominated sediment transport downstream. More than 95% of the sediments transported from the upstream basins were trapped in the reservoir, a fact that explains the sediment deficit and the river bed armouring observed downstream. Overall, the dam disrupted the natural water and sediment fluxes, generating a highly modified environment downstream. Below the dam, the whole ecosystem shifted to stable conditions owing to the reduction of water and sediment loads.

  8. The influence of El Niño–Southern Oscillation regimes on eastern African vegetation and its future implications under the RCP8.5 warming scenario

    National Research Council Canada - National Science Library

    Istem Fer; Britta Tietjen; Florian Jeltsch; Christian Wolff

    2017-01-01

    The El Niño–Southern Oscillation (ENSO) is the main driver of the interannual variability in eastern African rainfall, with a significant impact on vegetation and agriculture and dire consequences for food and social security...

  9. The geomorphic effects of dams on rivers: some examples from southern Italy

    Science.gov (United States)

    Rosskopf, Carmen Maria; Scorpio, Vittoria

    2017-04-01

    During the second half of the last century, many rivers in southern Italy have experienced huge channel adjustments mainly induced by anthropic interventions. Particularly, in several cases dams were built along them mainly to meet the growing need for energy and water for irrigation purposes. The present study investigates the cases of Fortore and Biferno rivers, whose lower courses are regulated respectively since 1966 and 1976 by the Occhito and Ponteliscione dams, with the aim to verify possible impacts of the dams on channel morphology and adjustments over the last 60 years. Channel changes were analyzed by means of a multi-temporal GIS analysis of topographic maps and aerial photographs integrated with topographic and geomorphological field. The obtained evolutionary trajectories highlight that channel adjustments occurred through two distinct phases and led to an overall channel narrowing and channel bed lowering accompanied by pattern changes in prevalence from multithread to single-thread channel configurations. Major channel adjustments occurred in the first phase, from the 1950s until the end of the 1990s, under the dominant control of in-channel mining, channel works and hydraulic interventions. Regarding this phase, the impact of the dams is highlighted by net differences in the amount of channel adjustments of the reaches located respectively upstream and downstream of them. Especially channel narrowing was more intense in downstream reaches (up to 98% in the Fortore River and up to 96% in the Biferno River) than in upstream reaches (up to 81% in the Fortore and up to 86% in the Biferno). With respectively 7.4 m y-1 and -7.8 m y-1, averages rates of narrowing are very similar for the Fortore and Biferno in downstream reaches. Observed differences suggest that, besides the control factors that guided the evolution of the entire fluvial systems, the closure of the two dams had additional and permanent effects on downstream reaches through overall

  10. Reconnaissance of the Black River, a cold-water river in the north-central part of Michigan's southern peninsula

    Science.gov (United States)

    Hendrickson, G.E.; Doonan, C.J.

    1971-01-01

    The cold-water streams of the northern states provide unique recreational values to the American people (wilderness or semi-wilderness atmosphere, fast-water canoeing, trout fishing) but the expanding recreational needs must be balanced against the growing demand of water for public and industrial supplies, for irrigation, and for the dilution of sewage and other wastes. In order to make intelligent decisions regarding use and management of the water resource for recreation and other demands, an analysis of the hydrologic factors related to recreational values is essential.The Black River north of Johannesburg in Otsego County has been rated by many fisherman as the number one brook-trout stream in the north-central part of the southern peninsula of Michigan. Headwaters are a few miles north of Johannesburg, and the Black flows northward to join the Cheboygan river a few miles south of Cheyboygan. Only the part of the Black upstream from the impoundment at Tower is included in this report.The headwaters of the Black can be reached by driving east and north from Gaylord, or east from Vanderbilt. The lower reaches included in this study can be reached from Tower or Onaway.The recreational value of a river depends on the characteristics of streamflow, water-quality, and its bed and banks. The purpose of this atlas is to describe these characteristics and to show how they relate to recreational uses.Some of the information presented here was derived from basic records of the U.S. Geological Survey's Water-Resources Division. Additional information was obtained in field reconnaissance surveys in 1966 and 1968. The study was made in cooperation with the Michigan Geological Survey, Gerald E. Eddy, Chief. Advice and assistance were also obtained from other sections of the Michigan Conservation Department.Sheet 1 of this atlas presents information on streamflow characteristics and water quality. Sheet 2 describes the physical character of the stream channel, bed and banks

  11. The Palaeolithic occupation of southern Alentejo: the Sado River Drainage Survey

    Directory of Open Access Journals (Sweden)

    Burke, Ariane

    2011-06-01

    Full Text Available The Sado River Drainage Survey project (2004-2008 was designed to fill a significant gap in our knowledge of the prehistory of Portugal. Southern Alentejo constitutes nearly one third of the total land mass of continental Portugal, but has received comparatively little attention from Palaeolithic archaeologists. Practically nothing was known about the prehistory of the Sado River basin, which includes the southern Alentejo plain, before now. The results of the Sado River Drainage Survey (SRDS indicate that the Sado River basin was likely occupied at low population densities during the Middle Palaeolithic. There is some evidence for a Lower Palaeolithic presence but little or no evidence of an Upper Palaeolithic occupation. The emerging pattern suggests either an occupational hiatus or a major shift in settlement pattern towards the end of the Middle Palaeolithic. Possible explanations for this pattern, including aridification driven by climate change, are explored here.

    El proyecto de prospección de la cuenca del río Sado (SRDS, llevado a cabo entre el 2004 y el 2008, se diseñó para suplir la carencia de información concerniente al conocimiento actual de la Prehistoria de Portugal. Aunque la cuenca del río Sado conforma casi un tercio de la superficie continental de Portugal, aún no había recibido la debida atención para el Paleolítico. Antes de este proyecto, prácticamente nada se conocía acerca de la Prehistoria de dicha cuenca, incluyendo la llanura de Alentejo. Nuestros resultados indican una baja densidad de población durante el Paleolítico Medio, rastro de ocupaciones del Paleolítico Inferior y casi ninguna evidencia de ocupaciones asociadas al Paleolítico Reciente. A partir de los datos obtenidos, se desprende un modelo en el que se evidencia que, hacia finales del Paleolítico Medio, hubo una discontinuidad en la ocupación, probablemente asociada a cambios climáticos o del uso del territorio.

  12. Investigation of regional trends and seasonal shifts in the river flow ...

    African Journals Online (AJOL)

    The historical trend and variability of river is investigated in 502 river flow gauging in 9 countries of the Southern African region with a view to document the special variability of the river flow regimes. The study identifies regions with strong evidence of declining or increasing trend in annual runoff and those with strong ...

  13. Micrandra inundata (Euphorbiaceae), a new species with unusual wood anatomy from black-water river banks in southern Venezuela

    Science.gov (United States)

    Paul E. Berry; Alex C. Wiedenhoeft

    2004-01-01

    Micrandra inundata is a distinctive new species adapted to seasonally flooded black-water river banks in southern Venezuela. Trees rarely exceed 10 m in height but have thick basal trunks composed of very lightweight wood. It has the smallest leaves and fruits of any known Micrandra species and appears to be most closely related to M. minor Benth. The botanical...

  14. Pseudoleptonema tansoongnerni new species (Hydropsychidae: Trichoptera) with species list of Trichoptera from Li Phi Falls, Mekong River, southern Laos.

    Science.gov (United States)

    Laudee, Pongsak; Malicky, Hans

    2017-03-10

    A new species named Pseudoleptonema tansoongnerni n. sp. is presented along with a list of Trichoptera from Li Phi falls, Mekong River, southern Laos. Pseudoleptonema tansoongnerni n. sp. is described and figured based on adult males and females. It is distinguished from the others by its forewing pattern and color, which is yellowish brown.

  15. Pleistocene aridification cycles shaped the contemporary genetic architecture of Southern African baboons.

    Directory of Open Access Journals (Sweden)

    Riashna Sithaldeen

    Full Text Available Plio-Pleistocene environmental change influenced the evolutionary history of many animal lineages in Africa, highlighting key roles for both climate and tectonics in the evolution of Africa's faunal diversity. Here, we explore diversification in the southern African chacma baboon Papio ursinus sensu lato and reveal a dominant role for increasingly arid landscapes during past glacial cycles in shaping contemporary genetic structure. Recent work on baboons (Papio spp. supports complex lineage structuring with a dominant pulse of diversification occurring 1-2Ma, and yet the link to palaeoenvironmental change remains largely untested. Phylogeographic reconstruction based on mitochondrial DNA sequence data supports a scenario where chacma baboon populations were likely restricted to refugia during periods of regional cooling and drying through the Late Pleistocene. The two lineages of chacma baboon, ursinus and griseipes, are strongly geographically structured, and demographic reconstruction together with spatial analysis of genetic variation point to possible climate-driven isolating events where baboons may have retreated to more optimum conditions during cooler, drier periods. Our analysis highlights a period of continuous population growth beginning in the Middle to Late Pleistocene in both the ursinus and the PG2 griseipes lineages. All three clades identified in the study then enter a state of declining population size (Nef through to the Holocene; this is particularly marked in the last 20,000 years, most likely coincident with the Last Glacial Maximum. The pattern recovered here conforms to expectations based on the dynamic regional climate trends in southern Africa through the Pleistocene and provides further support for complex patterns of diversification in the region's biodiversity.

  16. Mainstreaming biodiversity and wildlife management into climate change policy frameworks in selected east and southern African countries

    OpenAIRE

    Olga L. Kupika; Godwell Nhamo

    2016-01-01

    The Rio+20 outcomes document, the Future We Want, enshrines green economy as one of the platforms to attain sustainable development and calls for measures that seek to address climate change and biodiversity management. This paper audits climate change policies from selected east and southern African countries to determine the extent to which climate change legislation mainstreams biodiversity and wildlife management. A scan of international, continental, regional and national climate change ...

  17. History and origin of the HIV-1 subtype C epidemic in South Africa and the greater southern African region.

    Science.gov (United States)

    Wilkinson, Eduan; Engelbrecht, Susan; de Oliveira, Tulio

    2015-11-17

    HIV has spread at an alarming rate in South Africa, making it the country with the highest number of HIV infections. Several studies have investigated the histories of HIV-1 subtype C epidemics but none have done so in the context of social and political transformation in southern Africa. There is a need to understand how these processes affects epidemics, as socio-political transformation is a common and on-going process in Africa. Here, we genotyped strains from the start of the epidemic and applied phylodynamic techniques to determine the history of the southern Africa and South African epidemic from longitudinal sampled data. The southern African epidemic's estimated dates of origin was placed around 1960 (95% HPD 1956-64), while dynamic reconstruction revealed strong growth during the 1970s and 80s. The South African epidemic has a similar origin, caused by multiple introductions from neighbouring countries, and grew exponentially during the 1980s and 90s, coinciding with socio-political changes in South Africa. These findings provide an indication as to when the epidemic started and how it has grown, while the inclusion of sequence data from the start of the epidemic provided better estimates. The epidemic have stabilized in recent years with the expansion of antiretroviral therapy.

  18. Why is Southern African canine babesiosis so virulent? An evolutionary perspective

    Directory of Open Access Journals (Sweden)

    Penzhorn Barend L

    2011-04-01

    Full Text Available Abstract Canine babesiosis is a common, highly virulent disease in Southern Africa with even pups and juveniles being severely affected. This contrasts with bovine babesiosis, for example, where host, parasite and vector co-evolved and young animals develop immunity after infection without showing clinical signs. Babesia rossi, the main causative organism of canine babesiosis in sub-Saharan Africa, was first described from a side-striped jackal (Canis adustus in Kenya. Although data are meagre, there is evidence that indigenous African canids, such as jackals and wild dogs (Lycaon pictus, can harbour the parasite without showing untoward effects. Dogs are not indigenous to Africa. The vast majority of dogs presented at veterinary facilities in South Africa represent recently introduced European, Asian or American breeds. The contention is that B. rossi is a new challenge to which these dogs have not adapted. With intensive treatment of clinical cases, natural selection is effectively negated and the status quo will probably be maintained indefinitely. It is postulated that Babesia vogeli, which frequently results in unapparent infections or mild manifestations in dogs, represents or is closely related to the ancestral form of the canine parasite, possibly originating from wolves (Canis lupus.

  19. Why is Southern African canine babesiosis so virulent? An evolutionary perspective.

    Science.gov (United States)

    Penzhorn, Barend L

    2011-04-13

    Canine babesiosis is a common, highly virulent disease in Southern Africa with even pups and juveniles being severely affected. This contrasts with bovine babesiosis, for example, where host, parasite and vector co-evolved and young animals develop immunity after infection without showing clinical signs. Babesia rossi, the main causative organism of canine babesiosis in sub-Saharan Africa, was first described from a side-striped jackal (Canis adustus) in Kenya. Although data are meagre, there is evidence that indigenous African canids, such as jackals and wild dogs (Lycaon pictus), can harbour the parasite without showing untoward effects. Dogs are not indigenous to Africa. The vast majority of dogs presented at veterinary facilities in South Africa represent recently introduced European, Asian or American breeds. The contention is that B. rossi is a new challenge to which these dogs have not adapted. With intensive treatment of clinical cases, natural selection is effectively negated and the status quo will probably be maintained indefinitely. It is postulated that Babesia vogeli, which frequently results in unapparent infections or mild manifestations in dogs, represents or is closely related to the ancestral form of the canine parasite, possibly originating from wolves (Canis lupus).

  20. Southern African HIV Clinicians Society adult antiretroviral therapy guidelines: Update on when to initiate antiretroviral therapy

    Directory of Open Access Journals (Sweden)

    Graeme Meintjes

    2015-12-01

    Full Text Available The most recent version of the Southern African HIV Clinicians Society’s adult antiretroviral therapy (ART guidelines was published in December 2014. In the 27 August 2015 edition of the New England Journal of Medicine, two seminal randomised controlled trials that addressed the optimal timing of ART in HIV-infected patients with high CD4 counts were published: Strategic timing of antiretroviral therapy (START and TEMPRANO ANRS 12136 (Early antiretroviral treatment and/or early isoniazid prophylaxis against tuberculosis in HIV-infected adults. The findings of these two trials were consistent: there was significant individual clinical benefit from starting ART immediately in patients with CD4 counts higher than 500 cells/μL rather than deferring until a certain lower CD4 threshold or clinical indication was met. The findings add to prior evidence showing that ART reduces the risk of onward HIV transmission. Therefore, early ART initiation has the public health benefits of potentially reducing both HIV incidence and morbidity. Given this new and important evidence, the Society took the decision to provide a specific update on the section of the adult ART guidelines relating to when ART should be initiated.

  1. Brown oculocutaneous albinism is allelic to tyrosinase-positive oculocutaneous albinism in southern African Negroids

    Energy Technology Data Exchange (ETDEWEB)

    Manga, P.; Ramsay, M.; Kromberg, J.; Jenkins, T. [Univ. of the Witwatersrand, Johannesburg (South Africa)

    1994-09-01

    Brown oculocutaneous albinism (BOCA) is an autosomal recessive disorder involving a decrease in pigment of the skin, hair and eyes as well as decreased visual acuity. Evidence from two families who have co-existent BOCA and tyrosinase-positive oculocutaneous albinism (ty-pos OCA), suggests that the two conditions are allelic. Ty-pos OCA has been mapped to chromosome 15q11-q12 and the gene has been confirmed to be the human homologue (P) of the mouse pink-eyed dilute gene (p). Seven markers known to be linked to the P gene, D15S11, D15S10, MS14, GABA3, GABA5, IR10 and pCMW-1, were used to construct haplotypes in 5 families with BOCA. The haplotype data was subjected to linkage analysis and a maximum lod score of 2.85 ({theta} 0.0) was obtained. It has been reported previously that BOCA, in an Afro-American, was due to the lack of tyrosinase-protein 1 (Trp-1) in melanocytes. Trp-1 has been excluded as the disease-causing locus in the southern African families by linkage analysis with D9S43. A lod score of -2.02 was obtained at {theta} = 0.02.

  2. The African cynodont Aleodon (Cynodontia, Probainognathia in the Triassic of southern Brazil and its biostratigraphic significance.

    Directory of Open Access Journals (Sweden)

    Agustín G Martinelli

    Full Text Available In this contribution we report the first occurrence of the enigmatic African probainognathian genus Aleodon in the Middle-early Late Triassic of several localities from the state of Rio Grande do Sul in southern Brazil. Aleodon is unusual among early probainognathians in having transversely-expanded postcanine teeth, similar to those of gomphodont cynognathians. This genus was previously known from the Manda Beds of Tanzania and the upper Omingonde Formation of Namibia. The Brazilian record of this genus is based upon multiple specimens representing different ontogenetic stages, including three that were previously referred to the sectorial-toothed probainognathian Chiniquodon theotonicus. We propose a new species of Aleodon (A. cromptoni sp. nov. based on the specimens from Brazil. Additionally, we tentatively refer one specimen from the upper Omingonde Formation of Namibia to this new taxon, strengthening biostratigraphic correlations between these strata. Inclusion of A. cromptoni in a phylogenetic analysis of eucynodonts recovers it as the sister-taxon of A. brachyrhamphus within the family Chiniquodontidae. The discovery of numerous specimens of Aleodon among the supposedly monospecific Chiniquodon samples of Brazil raises concerns about chiniquodontid alpha taxonomy, particularly given the extremely broad geographic distribution of Chiniquodon. The discovery of Brazilian Aleodon and new records of the traversodontid Luangwa supports the hypothesis that at least two subzones can be recognized in the Dinodontosaurus Assemblage Zone.

  3. Regional health governance: A suggested agenda for Southern African health diplomacy.

    Science.gov (United States)

    Penfold, Erica Dale; Fourie, Pieter

    2015-12-01

    Regional organisations can effectively promote regional health diplomacy and governance through engagement with regional social policy. Regional bodies make decisions about health challenges in the region, for example, the Union of South American Nations (UNASUR) and the World Health Organisation South East Asia Regional Office (WHO-SEARO). The Southern African Development Community (SADC) has a limited health presence as a regional organisation and diplomatic partner in health governance. This article identifies how SADC facilitates and coordinates health policy, arguing that SADC has the potential to promote regional health diplomacy and governance through engagement with regional social policy. The article identifies the role of global health diplomacy and niche diplomacy in health governance. The role of SADC as a regional organisation and the way it functions is then explained, focusing on how SADC engages with health issues in the region. Recommendations are made as to how SADC can play a more decisive role as a regional organisation to implement South-South management of the regional social policy, health governance and health diplomacy agenda.

  4. The African cynodont Aleodon (Cynodontia, Probainognathia) in the Triassic of southern Brazil and its biostratigraphic significance.

    Science.gov (United States)

    Martinelli, Agustín G; Kammerer, Christian F; Melo, Tomaz P; Paes Neto, Voltaire D; Ribeiro, Ana Maria; Da-Rosa, Átila A S; Schultz, Cesar L; Soares, Marina Bento

    2017-01-01

    In this contribution we report the first occurrence of the enigmatic African probainognathian genus Aleodon in the Middle-early Late Triassic of several localities from the state of Rio Grande do Sul in southern Brazil. Aleodon is unusual among early probainognathians in having transversely-expanded postcanine teeth, similar to those of gomphodont cynognathians. This genus was previously known from the Manda Beds of Tanzania and the upper Omingonde Formation of Namibia. The Brazilian record of this genus is based upon multiple specimens representing different ontogenetic stages, including three that were previously referred to the sectorial-toothed probainognathian Chiniquodon theotonicus. We propose a new species of Aleodon (A. cromptoni sp. nov.) based on the specimens from Brazil. Additionally, we tentatively refer one specimen from the upper Omingonde Formation of Namibia to this new taxon, strengthening biostratigraphic correlations between these strata. Inclusion of A. cromptoni in a phylogenetic analysis of eucynodonts recovers it as the sister-taxon of A. brachyrhamphus within the family Chiniquodontidae. The discovery of numerous specimens of Aleodon among the supposedly monospecific Chiniquodon samples of Brazil raises concerns about chiniquodontid alpha taxonomy, particularly given the extremely broad geographic distribution of Chiniquodon. The discovery of Brazilian Aleodon and new records of the traversodontid Luangwa supports the hypothesis that at least two subzones can be recognized in the Dinodontosaurus Assemblage Zone.

  5. Reverberation Mapping of PG 0934+013 with the Southern African Large Telescope

    Science.gov (United States)

    Park, Songyoun; Woo, Jong-Hak; Romero-Colmenero, Encarni; Crawford, Steven M.; Park, Dawoo; Cho, Hojin; Jeon, Yiseul; Choi, Changsu; Barth, Aaron J.; Pei, Liuyi; Hickox, Ryan C.; Sung, Hyun-Il; Im, Myungshin

    2017-10-01

    We present the variability and time-lag measurements of PG 0934+013 based on a photometric and spectroscopic monitoring campaign over a two year period. We obtained 46 epochs of data from the spectroscopic campaign, which was carried out using the Southern African Large Telescope with ˜1 week cadence over two sets of four month-long observing period, while we obtained 80 epochs of B-band imaging data using a few 1 m class telescopes. Due to the seven month gap between the two observing periods, we separately measured the time lags of broad emission lines, including Hβ, by comparing the emission line light curve with the B-band continuum light curve using the cross-correlation function techniques. We determined the Hβ lag, {τ }{cent}={8.46}-2.14+2.08 days in the observed frame based on Year 2 data, while the time lag from Year 1 data was not reliably determined. Using the rms spectrum of Year 2 data, we measured the Hβ line dispersion {σ }{line} = 668 ± 44 km s-1 after correcting for the spectral resolution. Adopting a virial factor f = 4.47 from Woo et al. (2015), we determined the black hole mass M BH = {3.13}-0.93+0.91× {10}6 M ⊙, based on the Hβ time lag and velocity.

  6. NOM characterization and removal at six Southern African water treatment plants

    Directory of Open Access Journals (Sweden)

    J. Haarhoff

    2010-04-01

    Full Text Available Organic pollution is a major concern during drinking water treatment. Major challenges attributed to organic pollution include the proliferation of pathogenic micro-organisms, prevalence of toxic and physiologically disruptive organic micro-pollutants, and quality deterioration in water distribution systems. A major component of organic pollution is natural organic matter (NOM. The operational mechanisms of most unit processes are well understood. However, their interaction with NOM is still the subject of scientific research. This paper takes the form of a meta-study to capture some of the experiences with NOM monitoring and analysis at a number of Southern African Water Treatment Plants. It is written from the perspective of practical process selection, to try and coax some pointers from the available data for the design of more detailed pilot work. NOM was tracked at six water treatment plants using dissolved organic carbon (DOC measurements. Fractionation of the DOC based on biodegradability and molecular weight distribution was done at a water treatment plant in Namibia. A third fractionation technique using ion exchange resins was used to assess the impact of ozonation on DOC. DOC measurements alone did not give much insight into NOM evolution through the treatment train. The more detailed characterization techniques showed that different unit processes preferentially remove different NOM fractions. Therefore these techniques provide better information for process design and optimisation than the DOC measurement which is routinely done during full scale operation at these water treatment plants.

  7. The Bible and evolution: Opinions amongst southern African clergy and theologians from the Reformed church tradition

    Directory of Open Access Journals (Sweden)

    Peet J. van Dyk

    2013-02-01

    Full Text Available The main objectives of the present study were to determine the opinions of southern African clergy and theologians (from the Reformed church tradition about evolution and faith and to assess their degree of knowledge regarding the biological theory of evolution. A total of 1720 structured electronic questionnaires were sent out via email to all clergy belonging to the �Nederduitse Gereformeerde� and �Hervormde� churches, of which 89 were received back. The SPSS 20 statistical program was used to conduct descriptive and inferential statistical analyses of these data. Most participants were positive about the theory of biological evolution, but expressed the belief that evolution should be seen as a process guided by God. However, most participants failed to appreciate the fact that this view was contrary to the non-teleological nature of the biological theory of evolution and failed to distinguish between what should be accepted in faith and what can be demonstrated or �proved� (e.g. as is common in intelligent design circles. Many participants were not clear about the finer aspects of evolutionary theory and therefore often believed common misconceptions about it. In conclusion, one could say that participants were positive about evolution and, at least nominally, agreed with non-fundamentalist views of the Bible.

  8. Southern African HIV Clinicians Society adult antiretroviral therapy guidelines: Update on when to initiate antiretroviral therapy

    Directory of Open Access Journals (Sweden)

    Graeme Meintjes

    2015-04-01

    Full Text Available The most recent version of the Southern African HIV Clinicians Society’s adult antiretroviral therapy (ART guidelines was published in December 2014. In the 27 August 2015 edition of the New England Journal of Medicine, two seminal randomised controlled trials that addressed the optimal timing of ART in HIV-infected patients with high CD4 counts were published: Strategic timing of antiretroviral therapy (START and TEMPRANO ANRS 12136 (Early antiretroviral treatment and/or early isoniazid prophylaxis against tuberculosis in HIV-infected adults. The findings of these two trials were consistent: there was significant individual clinical benefit from starting ART immediately in patients with CD4 counts higher than 500 cells/μL rather than deferring until a certain lower CD4 threshold or clinical indication was met. The findings add to prior evidence showing that ART reduces the risk of onward HIV transmission. Therefore, early ART initiation has the public health benefits of potentially reducing both HIV incidence and morbidity. Given this new and important evidence, the Society took the decision to provide a specific update on the section of the adult ART guidelines relating to when ART should be initiated.

  9. Biodiversity and distribution of the southern African sea cucumbers (Echinodermata: Holothuroidea).

    Science.gov (United States)

    Thandar, Ahmed S

    2015-12-17

    The history of the southern African holothuroid fauna south of the tropic of Capricorn, is updated and the biodiversity and distribution of the fauna discussed. All five currently recognized orders are represented, distributed over 24 families, 74 genera and 163 species. As many as 117 species are shelf forms comprising the following faunistic components : 36% Indo-Pacific, 12% West Indian Ocean, 1% Atlantic and 51% endemic. Four faunistic provinces are recognized : tropical Indo-Pacific Province on the east coast, extending to St Lucia in northern KwaZulu-Natal; the Subtropical (Natal) province, from this point to Port St. Johns in the Eastern Cape Province; the Warm Temperate (Agulhas) Province from this point to Cape Point in the Western Cape Province; and the Cold Temperate (Namaqua) from Cape Point to Walvis Bay in Namibia. Vertical distribution of the approximately 90 species collected from more than one locality is also given. The origin of the holothuroid fauna is briefly discussed and reiterated that the Indo-Pacific component moved in from the north mostly by way of the Mozambique-Agulhas Current. The origin of the endemic component is obscure but surmised that it is perhaps also of Indo-Pacific origin with negligible contribution from the Atlantic.

  10. Adjustment Experiences of African American Graduates of Historically Black Colleges or Universities Attending Graduate School at a Southern Predominantly White University

    OpenAIRE

    Alexander, Quentin Renard

    2001-01-01

    The purpose of this study was to examine the adjustment experiences of African American graduates of historically Black colleges or universities (HBCUs) attending graduate school at a Southern predominantly White university (PWU). A discussion of narratives and themes across participants provided information about the adjustment experiences of African American graduate students who transitioned from a university community where the student population was predominantly African American to one ...

  11. Emission of Volatile OrganoHalogens by Southern African Solar Salt Works

    Science.gov (United States)

    Kotte, Karsten; Weissflog, Ludwig; Lange, Christian Albert; Huber, Stefan; Pienaar, Jacobus J.

    2010-05-01

    Volatile organic compounds containing halogens - especially chlorine - have been considered for a long time of industrial origin only, and it was assumed that the production and emission of these compounds can easily be controlled by humans in case they will cause a threat for life on Earth. Since the middle of the 80ies of the last century it became clear that the biologically active organohalogens isolated by chemists are purposefully produced by nature as antibiotics or as antifeedant etc. To date more than 3800 organohalogens are known to be naturally produced by bio-geochemical processes. The global budgets of many such species are poorly understood and only now with the emergence of better analytical techniques being discovered. For example the compound chloromethane nature's production (5 GT) outdates the anthropogenic production (50 KT) by a factor of 100. Thus organohalogens are an interesting recent case in point since they can influence the ozone budget of the boundary layer, play a role in the production of aerosols and the climate change discussion. An intriguing observation is that most of the atmospheric CH3Cl and CH3Br are of terrestrial rather than of marine origin and that a number of halogenated small organic molecules are produced in soils. The high concentrations of halides in salt soils point to a possibly higher importance of natural halogenation processes as a source of volatile organohalogens. Terrestrial biota, such as fungi, plants, animals and insects, as well as marine algea, bacteria and archaea are known or suspected to be de-novo producers of volatile organohalogens. In recent years we revealed the possibility for VOX to form actively in water and bottom sediments of hyper-saline environments in the course of studying aridization processes during climatic warming. Due to the nature of their production process solar salt works, as to be found along-side the Southern African coast line but also upcountry, combine a variety of semi- and

  12. Atmospheric Rivers and floods in Southern California: Climate forcing of extreme weather events.

    Science.gov (United States)

    Hendy, I. L.; Heusser, L. E.; Napier, T.; Pak, D. K.

    2016-12-01

    Southern California has a Mediterranean type climate characterized by warm dry summers associated with the North Pacific High pressure system and cool, wet winters primarily associated in low pressure systems originating in the high latitude North Pacific. Extreme precipitation, however, is connected to strong zonal flow that brings warm, moist tropical across the Pacific (AKA atmospheric river). Here we present a revised record of flood events in Santa Barbara Basin that have been linked to atmospheric rivers focusing on events associated with transitions between known climate events using new radiocarbon chronology and detailed sediment composition. Flood events identified by homogenous grey layers are present throughout the Holocene with a recurrence every 110 years, but are particularly common (85 year recurrence) between 4,200 and 2,000 years BP. Interval between 6,500 and 4,500 commonly associated with dry conditions in California was associated with fewer flood events (recurrence interval increased to 176 years). Intervals of high lake levels in California associated with pluvials appear to be associated with more frequent extreme precipitation events. The longest recurrence interval (535 years) is associated with the Medieval Climate Anomaly. The season in which the atmospheric river occurs was estimated using the relative abundance of pollen within the flood deposit. The 735 and 1270 C.E. flood events are associated with May-June flowering vegetation, while the most recent events (1861-2 and 1761 C.E.) were associated with November to March flowering vegetation. This agrees with the December-January rainfall records of the historic 1861-62. We conclude the frequency of extreme precipitation events appears to increase as climate cools (e.g. the Little Ice Age).

  13. Low flows and reservoir management for the Durance River basin (Southern France) in the 2050s

    Science.gov (United States)

    Sauquet, Eric

    2015-04-01

    The Durance River is one of the major rivers located in the Southern part of France. Water resources are under high pressure due to significant water abstractions for human uses within and out of the natural boundaries of the river basin through an extended open channel network. Water demands are related to irrigation, hydropower, drinking water, industries and more recently water management has included water needs for recreational uses as well as for preserving ecological services. Water is crucial for all these activities and for the socio-economic development of South Eastern France. Both socio-economic development and population evolution will probably modify needs for water supply, irrigation, energy consumption, tourism, industry, etc. In addition the Durance river basin will have to face climate change and its impact on water availability that may question the sustainability of the current rules for water allocation. The research project R²D²-2050 "Risk, water Resources and sustainable Development within the Durance river basin in 2050" aims at assessing future water availability and risks of water shortage in the 2050s by taking into account changes in both climate and water management. R²D²-2050 is partially funded by the French Ministry in charge of Ecology and the Rhône-Méditerranée Water Agency. This multidisciplinary project (2010-2014) involves Irstea, Electricité de France (EDF), the University Pierre et Marie Curie (Paris), LTHE (CNRS), the Société du Canal de Provence (SCP) and the research and consultancy company ACTeon. A set of models have been developed to simulate climate at regional scale (given by 330 projections obtained by applying three downscaling methods), water resources (provided by seven rainfall-runoff models forced by a subset of 330 climate projections), water demand for agriculture and drinking water, for different sub basins of the Durance River basin upstream of Mallemort under present day and under future conditions

  14. Distinct responses of bacterial communities to agricultural and urban impacts in temperate southern African estuaries

    Science.gov (United States)

    Matcher, G. F.; Froneman, P. W.; Meiklejohn, I.; Dorrington, R. A.

    2018-01-01

    Worldwide, estuaries are regarded as amongst the most ecologically threatened ecosystems and are increasingly being impacted by urban development, agricultural activities and reduced freshwater inflow. In this study, we examined the influence of different human activities on the diversity and structure of bacterial communities in the water column and sediment in three distinct, temperate permanently open estuarine systems within the same geographic region of southern Africa. The Kariega system is freshwater-deprived and is considered to be relatively pristine; the Kowie estuary is marine-dominated and impacted by urban development, while the Sundays system is fresh-water dominated and impacted by agricultural activity in its catchment. The bacterial communities in all three systems comprise predominantly heterotrophic species belonging to the Bacteroidetes and Proteobacteria phyla with little overlap between bacterioplankton and benthic bacterial communities at the species level. There was overlap between the operational taxonomic units (OTUs) of the Kowie and Kariega, both marine-influenced estuaries. However, lower species richness in the Kowie, likely reflects the impact of human settlements along the estuary. The dominant OTUs in the Sundays River system were distinct from those of the Kariega and Kowie estuaries with an overall decrease in species richness and evenness. This study provides an important snapshot into the microbial population structures of permanently open temperate estuarine systems and the influence of anthropogenic impacts on bacterial diversity and community structure.

  15. Distribution and Geochemistry of Rare-Earth Elements in Rivers of Southern and Eastern Primorye (Far East of Russia)

    Science.gov (United States)

    Chudaev, O. V.; Bragin, I. V.; A, Kharitonova N.; Chelnokov, G. A.

    2016-03-01

    The distribution and geochemistry of rare earth elements (REE) in anthropogenic, technogenic and natural surface waters of southern and eastern Primorye, Far East of Russia, are presented in this study. The obtained results indicated that most of REE (up to 70%) were transported as suspended matter, ratio between dissolved and suspended forms varing from the source to the mouth of rivers. It is shown that all REE (except Ce) in the source of the rivers are predominantly presented in dissolved form, however, the content of light and heavy REE is different. Short-term enrichment of light rare earth elements (LREE) caused by REE-rich runoff from waste dumps and mining is neutralized by the increase in river flow rate. Rivers in urban areas are characterized by high content of LREE in dissolved form and very low in suspended one.

  16. Modeling climate change induced hydrological extremes in the Kafue River Basin in Southern Africa

    Science.gov (United States)

    Ngongondo, C.; Li, L.; Gong, L.; Xu, C.-Y.

    2012-04-01

    Climate change impact projections in southern Africa suggest significant declines in flows in the major river basins. However, impacts of climate change on hydrological extremes (floods) in the region remain a grey area despite the threat they pose to human life and property. In this study, the impacts of climate change on extreme flows in the upper Kafue River basin, a major tributary of the Zambezi River, were investigated. Catchment hydrography was determined using the Hydro1k at a spatial resolution of 1 km resulting in an approximate registered area of 23,000 km2. The daily global WASMOD-M model was calibrated and validated during 1971 to 2001 with the WATCH Forcing Data (WFD) against observed discharge at Machiya gauging station from the Gridded River Discharge Data Centre(GRDC). Future climate change scenarios for extreme flows were derived by forcing the model with outputs from three GCM's (ECHAM, CMCC3 and IPSL) under the IPCC's SRES A2 and B1 scenarios from 2020 to 2100 at daily timescale. During calibration and validation, the NS coefficient value was above 0.80 and the Pearson correlation coefficient between observed and simulated flows of 0.9, suggesting acceptable model performance. Current and future extremes for each scenario were analyzed using the Peak Over Threshold (POT) analysis fitted to the Generalised Pareto Distribution (GPA), which provided less RMSE values as compared to Annual Maximum Series (AMS) fitted to the Generalized Extreme Value (GEV) distribution. The results show considerable departures from the reference period extremes for most of GCM scenarios considered, with both the A2 and B1 scenarios of the IPSL resulting in higher projected flows as compared to the other two models. On average, floods with return periods T=5,10,50,100,1000 years increased from Q (m3 s-1) = 626.6, 673.9, 767.1, 802.3, 903.7 during the reference period to Q (m3s-1) = 793.5, 873.4, 1046.2, 1119.2, 1364.8 respectively. The approach in our study has a

  17. Influence of El Niño-Southern Oscillation (ENSO) on the behavior of floods in the Itajaí River basin in Southern Brazil

    Science.gov (United States)

    Tiago Silva, Artur; Portela, Maria Manuela; Naghettini, Mauro; Fernandes, Wilson

    2016-04-01

    The Itajaí River basin is located in the Southeastern South America (SESA) region, where the influence of El Niño-Southern Oscillation (ENSO) on hydrometeorological extremes has been reported. The lower reaches of the river are prone to calamitous floods as the basin is frequently subjected to extreme rainfall events. The history of devastating floods motivated the construction of detention dams in the upper reaches of the river during the 1970s-1990s. This work presents a study on the nonstationarity of floods in the Itajaí River, using a peaks-over-threshold (POT) approach applied to flood data from 3 gauging stations located in the Basin. Exploratory data analysis methods and nonstationary Poisson-Generalized Pareto models are used to study the joint influence of ENSO and upstream flood control dams on the flood regime of the river. Bayesian model estimation techniques are used with prior belief about the Generalized Pareto shape parameter elicited from regional information. The analysis revealed that occurrence rate and over-threshold peak magnitudes exhibit statistically significant and complex relationships with ENSO. Results also show evidence that, while upstream flood detention dams play a perceptible, though small, role in reducing flood hazard, the influence of the climate covariate on the flood regime is dominant. Furthermore, increased ENSO activity in recent decades, possibly related to a reported climate regime shift in the mid-1970s, has increased flood hazard and led to the occurrence of very large annual floods.

  18. The second Southern African Bird Atlas Project: Causes and consequences of geographical sampling bias.

    Science.gov (United States)

    Hugo, Sanet; Altwegg, Res

    2017-09-01

    Using the Southern African Bird Atlas Project (SABAP2) as a case study, we examine the possible determinants of spatial bias in volunteer sampling effort and how well such biased data represent environmental gradients across the area covered by the atlas. For each province in South Africa, we used generalized linear mixed models to determine the combination of variables that explain spatial variation in sampling effort (number of visits per 5' × 5' grid cell, or "pentad"). The explanatory variables were distance to major road and exceptional birding locations or "sampling hubs," percentage cover of protected, urban, and cultivated area, and the climate variables mean annual precipitation, winter temperatures, and summer temperatures. Further, we used the climate variables and plant biomes to define subsets of pentads representing environmental zones across South Africa, Lesotho, and Swaziland. For each environmental zone, we quantified sampling intensity, and we assessed sampling completeness with species accumulation curves fitted to the asymptotic Lomolino model. Sampling effort was highest close to sampling hubs, major roads, urban areas, and protected areas. Cultivated area and the climate variables were less important. Further, environmental zones were not evenly represented by current data and the zones varied in the amount of sampling required representing the species that are present. SABAP2 volunteers' preferences in birding locations cause spatial bias in the dataset that should be taken into account when analyzing these data. Large parts of South Africa remain underrepresented, which may restrict the kind of ecological questions that may be addressed. However, sampling bias may be improved by directing volunteers toward undersampled regions while taking into account volunteer preferences.

  19. Systematics of the southern African genus Ixia (Iridaceae. 3. Sections Hyalis and Morphixia

    Directory of Open Access Journals (Sweden)

    P. Goldblatt

    2011-12-01

    Full Text Available A revised classification is presented for Ixia L., a southern African genus restricted to the winter rainfall zone of the western part of the subcontinent, in which the four sections Dichone (Salisb. ex Baker Goldblatt & J.C.Manning, Hyalis (Baker Diels, Ixia, and Morphixia (Ker Gawl. Pax are recognized and diagnosed. The circumscription of sect. Hyalis is emended to include both short- and long-tubed species, mostly with four or more leaves with the uppermost not sharply differentiated from the lower. This contrast with sect. Morphixia, also with short- and long-tubed species, in which the entirely sheathing uppermost leaf (rarely upper two leaves is distinct from the lower two or rarely three leaves, which have well-developed blades. We revise these two sections, recognizing 18 species in sect. Hyalis, including the two new species, I. linderi and I. recondita, and recognizing 31 species in sect. Morphixia, including the 11 new species, I. alata, I. cedarmontana, I. dolichosiphon, I. ecklonii, I. linearifolia, I. monticola (previously included in I. latifolia var. angustifolia, I. pavonia, I. parva and I. ramulosa (raised from varietal rank as var. parviflora and var. ramulosa respectively of I. latifolia, I. saundersiana and I. stenophylla (previously I. fucata var. filifolia. We also provide a new name, I. mollis for the illegitimate homonym I. flaccida. Lastly, we transfer I. purpureorosea from sect. Ixia to sect. Hyalis. We recognize eight informal series, three in sect. Hyalis and five in sect. Morphixia. With these changes and additions the genus Ixia now comprises 78 species.

  20. Systematics of the southern African genus Ixia (Iridaceae: Crocoideae: 4. Revision of sect. Dichone

    Directory of Open Access Journals (Sweden)

    P. Goldblatt

    2012-12-01

    Full Text Available The southern African genus Ixia L. comprises ± 90 species from the winter-rainfall zone of the subcontinent. Ixia sect. Dichone (Salisb. ex Baker Goldblatt & J.C.Manning, one of four sections in the genus and currently including 10 species and three varieties, is distinguished by the following floral characters: lower part of the perianth tube filiform and tightly clasping the style; filaments not decurrent; upper part of the perianth tube short to vestigial; style branches involute-tubular and stigmatic only at the tips; and so-called subdidymous anthers. We review the taxonomy of the section, providing complete descriptions and distribution maps, and a key to the species. I. amethystina Manning & Goldblatt is recognized to be a later synonym of I. brevituba G.J.Lewis. Most collections currently included under that name represent another species, here described as I. rigida. We recognize five additional species in the section: early summer-blooming I. altissima from the Cedarberg; I. bifolia from the Caledon District; I. flagellaris, a stoloniferous species from the Cedarberg; I. simulans from the western Langeberg; and I. tenuis from the Piketberg. We also raise to species rank I. micrandra var. confusa and var. minor, as I. confusa and I. minor respectively. Foliar and associated floral variation in the widespread I. scillaris has led us to recognize two new subspecies among its northern populations, broad leaved subsp. latifolia and the dwarfed, smaller flowered subsp. toximontana; subsp. scillaris is restricted to the immediate southwestern Cape, from Darling to Somerset West. Sect. Dichone now has 17 species and two subspecies.

  1. In vitro determination of the anti-aging potential of four southern African medicinal plants.

    Science.gov (United States)

    Ndlovu, Gugulethu; Fouche, Gerda; Tselanyane, Malefa; Cordier, Werner; Steenkamp, Vanessa

    2013-11-05

    Aging is an inevitable process for all living organisms. During this process reactive oxygen species generation is increased which leads to the activation of hyaluronidase, collagenase and elastase, which can further contribute to skin aging. Four southern African medicinal plants; Clerodendrum glabrum, Schotia brachypetala, Psychotria capensis and Peltophorum africanum, were investigated to assess their anti-aging properties. Anti-elastase, anti-collagenase and anti-hyaluronidase activities of twenty-eight samples, consisting of methanol and ethyl acetate extracts of the four plants, were determined using spectrophotometric methods. Radical scavenging activity was determined by the ability of the plant extracts to scavenge the ABTS•+ radical. The majority of the samples in the anti-elastase assay and nine in the anti-collagenase assay showed more than 80% inhibition. The ethyl acetate extract of S. brachypetala bark and leaves of P. capensis inhibited elastase activity by more than 90%. The methanol extract of S. brachypetala bark contained the highest anti-hyaluronidase activity (75.13 ± 7.49%) whilst the ethyl acetate extract of P. africanum bark exhibited the highest antioxidant activity (IC50: 1.99 ± 0.23 μg/ml). The free radical scavenging activity and enzyme inhibitory activity of the plant extracts investigated suggests that they can help restore skin elasticity and thereby slow the wrinkling process. P. africanum was the plant with the most promising activity and will be subjected to further testing and isolation of the active compound/s.

  2. Evolution of foraging behaviour: Deep intra-generic genetic divergence between territorial and non-territorial southern African patellid limpets.

    Science.gov (United States)

    Mmonwa, Kolobe L; Teske, Peter R; McQuaid, Christopher D; Barker, Nigel P

    2017-12-01

    Southern Africa is a biodiversity hotspot of patellid limpets, with three genera (Helcion, Cymbula and Scutellastra) identified and described in the region. Scutellastra is the most diverse and most frequently studied of these and, along with Cymbula, includes species with territorial and non-territorial foraging behaviours. We used three mitochondrial markers (12S rRNA, 16S rRNA and COI) and one nuclear marker (ATPSβ intron) to assess evolutionary relationships among species of Cymbula and Scutellastra with these two foraging behaviours and to identify which foraging mode is the more ancient. Maximum Likelihood and Bayesian Inference phylogenetic analyses revealed that the species sharing a foraging type are monophyletic in both genera. Territoriality is a derived character, as the clades with this foraging type are nested within a tree that otherwise comprises non-territorial taxa. These include Helcion, which was recovered as sister to the Cymbula/Scutellastra clade, and the next basal genus, Patella, which is ancestral to all southern African patellogastropods. Deep genetic divergence between the two foraging traits reflects strong adaptive effects of resource partitioning in the evolution of southern African patellid limpets. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Luminescence dosimetry in a contaminated settlement of the Techa River valley, Southern Urals, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Woda, C., E-mail: clemens.woda@helmholtz-muenchen.d [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, D-85764 Neuherberg (Germany); Ulanovsky, A. [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, D-85764 Neuherberg (Germany); Bougrov, N.G. [Urals Research Center for Radiation Medicine, Chelyabinsk (Russian Federation); Fiedler, I. [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, D-85764 Neuherberg (Germany); Degteva, M.O. [Urals Research Center for Radiation Medicine, Chelyabinsk (Russian Federation); Jacob, P. [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, D-85764 Neuherberg (Germany)

    2011-03-15

    Optically stimulated luminescence (OSL) dosimetry is applied to quartz extracted from bricks from a mill in a contaminated village (Muslyumovo) of the Techa River valley, Southern Urals, Russia, for the purpose of dose reconstruction. Previous works [. First international intercomparison of luminescence techniques using samples from the Techa river valley. Health Phys. 82, 94-101]have shown that the expected dose due to man-made sources of radiation in the bricks is in the same range as the background dose due to natural sources of radiation, therefore a precise estimate of the cumulative and background dose is of utmost importance. Cumulative doses could be assessed with OSL with a precision of around 4% and lie between 450 and 600 mGy. The background dose was carefully determined by a combination of laboratory measurements, in-situ gamma spectrometry and Monte Carlo modelling. The results show that the gamma-dose rate of the soil was overestimated and the fractional brick gamma-dose rate underestimated in previous studies, but that the overall gamma-dose rate was nearly correct, due to mutual compensation. The obtained anthropogenic doses in brick measured with OSL lie between 200 and 300 mGy, show variability between adjacent bricks within error limits for one spot but a significant difference for two samples is observed for another spot. A distinct dependency of measured dose upon sample height is observed, which is an indication of a source distribution, which extends over a large area and up to a certain depth into the soil and in which higher contaminated areas are located at a greater distance to the mill than lower contaminated areas. A measured dose-depth profile is compared with previously published Monte Carlo calculations to verify the source energy.

  4. Bio-accumulation of selected metals in African sharptooth catfish Clarias gariepinus from the lower Olifants River, Mpumalanga, South Africa

    Directory of Open Access Journals (Sweden)

    H.H. Du Preez

    1997-01-01

    Full Text Available The level of metal (Cr, Cu, Mn, Ni, Pb and Zn bio- accumulation in tissues (muscle, gill, kidney, liver and gonads and bile of the African catfish Clarias gariepinus, from the lower Olifants River was investigated. These metals were detected in all the tissues as well as in the bile, with the highest concentration found in either the gills, liver or gonadal tissue. The lowest concentration was usually detected in the muscle tissue. Although statistic comparisons revealed no significant differences between the localities, fish from the Selati River (Locality 1 generally had higher metal levels than fish from the localities along the Olifants River inside the Kruger National Park. The higher levels in the fish from the Selati River may be attributed to anthropogenic activities resulting in point and/or diffuse sources of metal pollution. These sources should be identified and reduced.

  5. Interannual variability of the summer precipitation and streamflow in coastal river basins in Southern Oaxaca, Mexico

    Science.gov (United States)

    Perez, N.; Kretzschmar, T.; Cavazos, T.; Munoz-Arriola, F.

    2013-05-01

    Interannual variability of summer rainfall and streamflow in coastal river basins in Southern Oaxaca, Mexico (Río Verde, Río Tehuantepec, and the Southern Coast) were compared and the relationship with El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) were evaluated. A regionalization based on an oblique-rotated component analysis (PCA) was applied to 47 climatological stations, in the period from 1960 to 1990, and four precipitation regions were defined. Seventeen streamflow stations were clustered according to the four regions derived from the PCA. A correlation between annual precipitation and annual streamflow in each region was carried out; in the four regions, streamflow variability was significantly correlated (95% level) with annual rainfall, with higher values in the wettest regions. Therefore, regional streamflow during the study period is modulated by interannual rainfall. A significant negative correlation at the 95 % level was only found with the Oceanic El Niño Index (ONI) in rainfall Region 3, nearest to the Gulf of Tehuantepec. Wet years, mainly were associated with SST anomalies (≥ -0.6°C) similar to weak La Niña and Neutral cool conditions, while dry years were associated with positive SST anomalies similar to Neutral warm conditions (≤ 0.5°C). This rainfall-streamflow relationship with ENSO means, that for example for years with La Niña conditions, the streamflow is expected to show the highest levels, which directly implicates the regional water resource management. In each derived PCA region, the top 95 percentile (P95) of daily precipitation events were also evaluated and divides as those derived from tropical cyclones (TC) of the Eastern Tropical Pacific (EPAC), and non-tropical cyclone (NTC) rainfall events. The largest contribution of extreme P95 precipitation derived from TCs to the annual precipitation was observed in Region 3. A significant upward trend in the contribution of TC

  6. Foraging strategies of Southern sea lion females in the La Plata River Estuary (Argentina-Uruguay)

    Science.gov (United States)

    Rodríguez, Diego H.; Dassis, Mariela; Ponce de León, Alberto; Barreiro, César; Farenga, Marcelo; Bastida, Ricardo O.; Davis, Randall W.

    2013-04-01

    The stocks of Southern sea lions (Otaria flavescens, SSL) and South American fur seals (SAFS) that breed on coastal islands of Uruguay constitute the most important focal concentration of pinnipeds in South America, with a significant increase in SAFS and a steady decrease of SSL over the past decades. Because females are a key element of population dynamics and no information exists on the post-breeding pup rearing period, we studied the foraging patterns of SSL females in the La Plata River Estuary (LPRE) during mid and late lactation (late austral autumn and winter), analyzing the foraging performance, geographic coverage and ontogenetic differences in foraging strategies for a period of 1-5 months. At-sea movements of 22 SSL females (6 subadults and 16 adults) from Isla de Lobos (IL, 35°01'28"S-54°52'59"W, Uruguay) were monitored using satellite transmitters (SPOT4, SPOT5 and STDR-S16, Wildlife Computers) in 2007 and 2010. An algorithm [McConnell, B.J., Chambers, C., Fedak, M.A., 1992. Foraging ecology of southern elephant seals in relation to the bathymetry and productivity of the Southern Ocean. Antarct. Sci. 4, 393-398.] with a maximum transit speed of 3 m s-1 was applied to the Argos information, resulting in a total of 2522 filtered locations. A daily mean of 3.5±1.74 filtered locations per animal was received. One hundred and eighty three foraging trips (FT) were recorded with no significant differences (plactating females decrease FT duration by increasing transit speed but maintain a similar spatial coverage compared with FT later in lactation. Although several aquatic areas of high priority for conservation in LPRE have been identified and proposed, only 15% of the foraging habitat of SSL females is currently included in these areas. This emphasizes the importance of the inclusion of the at-sea foraging distributions of central point foragers in marine protected areas. If conservation efforts focus only on coastal breeding concentrations, key

  7. The bi-decadal rainfall cycle, Southern Annular Mode and tropical cyclones over the Limpopo River Basin, southern Africa

    CSIR Research Space (South Africa)

    Malherbe, J

    2014-06-01

    Full Text Available contribution to rainfall by tropical cyclones and depressions. The findings suggest that a broadening of the Hadley circulation underpinned by an anomalous anticyclonic pattern to the east of southern Africa altered tropospheric steering flow, relative...

  8. The Common Agricultural Policy as a driver of water quality changes: the case of the Guadalquivir River Basin (southern Spain)

    OpenAIRE

    Salmoral, Gloria; Garrido, Alberto

    2015-01-01

    Several studies have analysed the effects of European environmental policies on water quality, but no detailed retrospective analysis of the impacts of the Common Agricultural Policy (CAP) reforms on observed water quality parameters has been carried out. This study evaluates the impact of the CAP and other drivers on the concentrations of nitrates and suspended solids in the Guadalquivir River Basin (southern Spain) over the 1999-2009 period. The most important drivers that are degrading bot...

  9. High-resolution stable isotope signature of a land-falling atmospheric river in Southern Norway

    Science.gov (United States)

    Weng, Yongbiao; Sodemann, Harald

    2017-04-01

    Gathering observational evidence of the long-range moisture versus local source contributions remains a scientific challenge, but is critical for understanding how hydrological extremes develop. Moisture transport to the west coast of Norway is often connected to elongated meridional structures of high water vapour flux known as Atmospheric Rivers. It is still an open question how well moisture sources estimated by different numerical models for such events of long-range transport correspond with reality. In this study, we present high resolution stable isotope information collected during a land-falling Atmospheric River in Southern Norway during winter 2016, and analyse the data with the aim to differentiate between moisture source signatures and below-cloud processes affecting the stable isotope composition. The precipitation characterised by a pronounced warm front was sampled manually on a rooftop platform at a 10-20 minute interval during the 24h of the event and later measured by a laser spectrometer (Picarro L2140-i) in the lab for δ18O, δD, and d-excess. Simultaneously, the stable isotope composition of water vapor was continuously measured at high resolution. To that end, ambient air was continuously pumped from a nearby inlet at 25 m above the ground and measured by another laser spectrometer (Picarro L2130-i). Stable water isotope measurements were supplemented by detailed precipitation parameters from a laser disdrometer (OTT Parsivel2), Micro Rain Radar (MRR-2), Total Precipitation Sensor (TPS-3100), and a nearby weather station. Measurements show a signature of two depletion periods in the main stable isotope parameters that are not apparent in precipitation amount and atmospheric temperature measurements. The deuterium excess in rainfall responds differently, with first and increase and then a decrease during these depletion periods. We interpret this as a combined consequence of airmass change, cloud microphysics, and below-cloud effects

  10. The influence of invasive Fallopia taxa on resident plant species in two river valleys (southern Poland

    Directory of Open Access Journals (Sweden)

    Damian Chmura

    2015-03-01

    Full Text Available Riparian zones in two rivers in southern Poland were studied in terms of species composition and soil parameters in patches dominated by three knotweed taxa (Fallopia japonica, F. sachalinensis and the hybrid F. ×bohemica. The main purpose was to detect any differences in species diversity, environmental conditions and in the impact of the three Fallopia spp. on resident species. Fieldwork was conducted in spring and summer in 30 invaded plots (in total 90 subplots. It was demonstrated that vegetation dominated by particular knotweed taxa differed in response to soil pH and ammonium, nitrate, and magnesium content. Fallopia spp. (living plants and necromass had a stronger negative impact on the cover and species diversity of the resident species in summer in comparison with spring. Vegetation patches differed significantly in species composition in relation to the knotweed taxa present. These differences may be the consequence of the differentiated biotopic requirements of Fallopia taxa and the coexisting plants, or to the different impact of the knotweed taxa on the resident species.

  11. DISEASE SCREENING IN SOUTHERN RIVER TERRAPINS ( BATAGUR AFFINIS EDWARDMOLLI) IN CAMBODIA.

    Science.gov (United States)

    Seimon, Tracie A; Horne, Brian D; Tomaszewicz, Ania; Pruvot, Mathieu; Som, Sitha; In, Samat; Sokha, Chea; Platt, Steve; Toledo, Patricia; McAloose, Denise; Calle, Paul P

    2017-12-01

    Southern River terrapins ( Batagur affinis) are among the most critically endangered turtles in the world. To augment the Cambodia population, a head-start program was established for the endemic subspecies Batagur affinis edwardmolli in 2006, and in 2015, prerelease health assessments were performed on 70 subadults (hatch years, 2006-2011). Combined choanal/cloacal swab samples ( n = 70) were collected and screened by polymerase chain reaction (PCR) for Mycoplasma, herpesvirus, and ranavirus. Cloacal samples ( n = 50) were also collected and cultured for Salmonella sp. Of 70 tested samples, six (8.6%) were positive for Mycoplasma, and all other PCR and culture test results were negative. Phylogenetic analysis of the 16S ribosomal RNA gene placed the Mycoplasma sp. from B. affinis edwardmolli in the chelonian Mycoplasma cluster that groups within the Mycoplasma pulmonis clade. This mollicute was not associated with clinical disease (defined as observable clinical abnormalities, such as depression, lethargy, respiratory signs, and anorexia) and is likely part of the endemic microbial flora of these terrapins.

  12. Temporal changes of land use in Asi river delta (Hatay, Southern Turkey).

    Science.gov (United States)

    Korkmaz, Hüseyin; Cetin, Bayram; Kuscu, Veysel; Ege, Ismail; Bom, Ahmet; Ozsahin, Emre; Karatas, Atilla

    2012-04-01

    Increasing non-ecological land use necessitates more efficient using and utilization of land by man. Therefore, in recent years studies on sustainable land use have gained momentum. In this study, temporal change in land use, mainly between years 1940 and 2010, in Asi river delta on Southern Turkey was covered. To this end, in addition to literature, topographical maps and satellite images from year 1940 and after were used. Also, data were collected through field studies and interviews. Collected data were evaluated from geographical viewpoint using Geographical information system (GIS) and Remote sensing (RS) methods. Unplanned settlement in delta has reached levels high enough to threaten agricultural fields. Especially, greattendencyshown by Samandag city and the villages around it towards expanding into delta is an indicatorof this threat In additon, uncontrolled sand mining and touristic facilities on the coastline are also indicators of wrong land use. In future, direction of settlement to slopes around the delta rather than lowlands will be a much more ecological approach.

  13. Historical evolution of slope instability in the Calore River Basin, Southern Italy

    Science.gov (United States)

    Diodato, Nazzareno; Soriano, Marcella; Bellocchi, Gianni; Fiorillo, Francesco; Cevasco, Andrea; Revellino, Paola; Guadagno, Francesco Maria

    2017-04-01

    There is interest in knowing historical spatio-temporal patterns of landslide activity. However, this is challenging to reconstruct because it is difficult to obtain detailed records for past landslide activity. Here, we deal with hydro-geomorphological signatures, such as storms, downpours, floods, snowmelt and mass movement, to detect annual slope instability events (ASIEs) over historical times. In order to obtain ASIEs for each year, a monthly Instability Density Index (IDI) was used and then monthly values were summed up to obtain a yearly value. Classes of monthly IDI varying between 0 (no instability) and 4 (highest instability) were determined from historical documents. We present an application for the Calore River Basin, Southern Italy, using data from a 313-year long series (1701-2013 CE). After 1880 CE the information becomes more valuable with directly observed landslide frequency. By this cataloguing, 129 ASIEs were obtained. Their evolution shows slight instability during the 18th century. Uneven and greater slope instability occurred instead across the 19th century, when an important phase of deforestation coincided with intensification of agricultural activities. Slope instability events continued during the 20th century but their causes are mainly related to anthropisation and the effects of recent climate change. It was determined that stormy autumns until the 19th century and successive winter-times with enhanced snowmelt, may have driven the reactivation of widespread instability events. We also found that mountainous and hilly terrains have an acute sensitivity to climate change.

  14. Soil erosion vulnerability in the verde river basin, southern minas gerais

    Directory of Open Access Journals (Sweden)

    Vinícius Augusto de Oliveira

    2014-06-01

    Full Text Available Soil erosion is one of the most significant environmental degradation processes. Mapping and assessment of soil erosion vulnerability is an important tool for planning and management of the natural resources. The objective of the present study was to apply the Revised Universal Soil Loss Equation (RUSLE using GIS tools to the Verde River Basin (VRB, southern Minas Gerais, in order to assess soil erosion vulnerability. A annual rainfall erosivity map was derived from the geographical model adjusted for Southeastern Brazil, calculating an annual value for each pixel. The maps of soil erodibility (K, topographic factor (LS, and use and management of soils (C were developed from soils and their uses map and the digital elevation model (DEM developed for the basin. In a GIS environment, the layers of the factors were combined to create the soil erosion vulnerability map according to RUSLE. The results showed that, in general, the soils of the VRB present a very high vulnerability to water erosion, with 58.68% of soil losses classified as "High" and "Extremely High" classes. In the headwater region of VRB, the predominant classes were "Very High" and "Extremely High" where there is predominance of Cambisols associated with extensive pastures. Furthermore, the integration of RUSLE/GIS showed an efficient tool for spatial characterization of soil erosion vulnerability in this important basin of the Minas Gerais state.

  15. Foraging ranges of immature African white-backed vultures (Gyps africanus and their use of protected areas in southern Africa.

    Directory of Open Access Journals (Sweden)

    W Louis Phipps

    Full Text Available Vultures in the Gyps genus are declining globally. Multiple threats related to human activity have caused widespread declines of vulture populations in Africa, especially outside protected areas. Addressing such threats requires the estimation of foraging ranges yet such estimates are lacking, even for widespread (but declining species such as the African white-backed vulture (Gyps africanus. We tracked six immature African white-backed vultures in South Africa using GPS-GSM units to study their movement patterns, their use of protected areas and the time they spent in the vicinity of supplementary feeding sites. All individuals foraged widely; their combined foraging ranges extended into six countries in southern Africa (mean (± SE minimum convex polygon area =269,103±197,187 km(2 and three of the vultures travelled more than 900 km from the capture site. All six vultures spent the majority of their tracking periods outside protected areas. South African protected areas were very rarely visited whereas protected areas in northern Botswana and Zimbabwe were used more frequently. Two of the vultures visited supplementary feeding sites regularly, with consequent reduced ranging behaviour, suggesting that individuals could alter their foraging behaviour in response to such sites. We show that immature African white-backed vultures are capable of travelling throughout southern Africa, yet use protected areas to only a limited extent, making them susceptible to the full range of threats in the region. The standard approach of designating protected areas to conserve species is unlikely to ensure the protection of such wide-ranging species against threats in the wider landscape.

  16. Fertilisation of the Southern Atlantic: Ephemeral River Valleys as a replenishing source of nutrient-enriched mineral aerosols

    Science.gov (United States)

    Dansie, Andrew; Wiggs, Giles; Thomas, David

    2016-04-01

    Oceanic dust deposition provides biologically important iron and macronutrients (Phosphorus (P) and Nitrogen-based (N) compounds) that contribute to phytoplankton growth, marine productivity and oceanic atmospheric CO2 uptake. Research on dust emission sources to date has largely focused on the northern hemisphere and on ephemeral lakes and pans. Our work considers the ephemeral river valleys of the west coast of Namibia as an important yet overlooked source of ocean-fertilizing dust. Dust plumes are frequently emitted from the river valleys by strong easterly winds during the Southern Hemisphere winter, when the upwelling of the Benguela Current is at its weakest. We present field data from dust emission source areas along the main river channels near the coastal termini of the Huab, Kuiseb and Tsauchab river valleys. Collected data include erodible surface sediment, wind-blown flux, and associated meteorological data. Extensive surface sediment sampling was also undertaken throughout the combined 34,250 km2 extent of each river valley catchment with samples collected from within the main river channels, the main branches of each river system, selected tributaries, and into the upper watersheds. Geochemical data show valley sediment and wind-blown flux material have high concentrations of bioavailable Fe, P and N, exceeding that measured at the major dry lake basin dust sources in southern Africa. The contribution of fertilising deposition material is enhanced by both the spatial proximity of the source areas to the ocean and enrichment of source material by ephemeral fluvial accumulation and desiccation. Results show that geographical factors within each watershed play a key role in the nutrient composition of the emitting fluvial deposits in the river valleys. Analysis explores potential relationships between land use, geology, climate and precipitation in the upper watersheds and their influence on bioavailability of Fe, P and N compounds in wind

  17. Tracking the Cretaceous transcontinental Ceduna River through Australia: The hafnium isotope record of detrital zircons from offshore southern Australia

    Directory of Open Access Journals (Sweden)

    Jarred Lloyd

    2016-03-01

    Full Text Available The middle–upper Cretaceous Ceduna River system traversed continental Australia from the NE coast to the centre of the southern coast. At its mouth, it formed a vast delta system that is similar in scale to the Niger delta of West Africa. The delta system is composed of two main lobes that represent different phases of delta construction. A recent hypothesis has challenged the traditional idea that both lobes of the delta were derived from a transcontinental river system by suggesting that the upper lobe (Santonian–Maastrichtian is instead derived from a restricted catchment within southern Australia. Hf isotopic data presented here fingerprint the original source of the upper delta lobe zircons to NE Australia, with data comparing well with similar U-Pb and Lu-Hf isotopic data from the Lachlan Orogen, the New England Orogen, the eastern Musgraves Province and the northern Flinders Ranges. These data do not preclude a model where the lobe is derived from recycled Eromanga Basin sediments during a phase of late Cretaceous inland Australian uplift, but when coupled with reconnaissance low-temperature thermochronometry from the region of the Ceduna River course indicating widespread Triassic–Jurassic exhumation, and comparisons with detrital zircon data from the Winton Formation upstream of any proposed uplift, we suggest that both lobes of the Ceduna Delta are likely to be derived from a transcontinental Ceduna River.

  18. Morphological analysis of Trichomycterus areolatus Valenciennes, 1846 from southern Chilean rivers using a truss-based system (Siluriformes, Trichomycteridae).

    Science.gov (United States)

    Colihueque, Nelson; Corrales, Olga; Yáñez, Miguel

    2017-01-01

    Trichomycterus areolatus Valenciennes, 1846 is a small endemic catfish inhabiting the Andean river basins of Chile. In this study, the morphological variability of three T. areolatus populations, collected in two river basins from southern Chile, was assessed with multivariate analyses, including principal component analysis (PCA) and discriminant function analysis (DFA). It is hypothesized that populations must segregate morphologically from each other based on the river basin that they were sampled from, since each basin presents relatively particular hydrological characteristics. Significant morphological differences among the three populations were found with PCA (ANOSIM test, r = 0.552, p < 0.0001) and DFA (Wilks's λ = 0.036, p < 0.01). PCA accounted for a total variation of 56.16% by the first two principal components. The first Principal Component (PC1) and PC2 explained 34.72 and 21.44% of the total variation, respectively. The scatter-plot of the first two discriminant functions (DF1 on DF2) also validated the existence of three different populations. In group classification using DFA, 93.3% of the specimens were correctly-classified into their original populations. Of the total of 22 transformed truss measurements, 17 exhibited highly significant (p < 0.01) differences among populations. The data support the existence of T. areolatus morphological variation across different rivers in southern Chile, likely reflecting the geographic isolation underlying population structure of the species.

  19. Water quality comparison of secondary effluent and reclaimed water to ambient river water of southern Okinawa Island via biological evaluation.

    Science.gov (United States)

    Mano, Hiroyuki; Takeda, Fumihiko; Kitamura, Tomokazu; Okamoto, Seiichiro; Suzuki, Yutaka; Park, Chang-Beom; Yasui, Nobuhito; Kobayashi, Kentarou; Tanaka, Yuji; Yamashita, Naoyuki; Minamiyama, Mizuhiko

    2017-08-08

    The objective of this work was to evaluate the biological effect of the secondary effluent (SE) of a wastewater treatment plant and reclaimed water treated via ultrafiltration (UF) followed by either reverse osmosis (RO) membrane filtration or nanofiltration (NF) to be used for environmental use by comparing the results of algal growth inhibition tests of concentrated samples of the SE and permeates of RO and NF with those of six rivers in southern Okinawa Island. Although the SE water had no adverse effects on the growth of the algae Pseudokirchneriella subcapitata, it could lead to water quality degradation of rivers in terms of its toxic unit value, whereas the use of RO and NF permeates would not lead to such degradation. The recharge of rivers, into which domestic wastewater and livestock effluents might be discharged in southern Okinawa Island, with reclaimed water subjected to advanced treatment could dilute the concentrations of chemicals that cause biological effects and improve the water quality of the rivers, based on the results of the bioassay using P. subcapitata. Comparing the results of bioassays of reclaimed water with those of the ambient water at a site might be effective in assessing the water quality of reclaimed water for environmental use at the site.

  20. Morphological analysis of Trichomycterus areolatus Valenciennes, 1846 from southern Chilean rivers using a truss-based system (Siluriformes, Trichomycteridae

    Directory of Open Access Journals (Sweden)

    Nelson Colihueque

    2017-09-01

    Full Text Available Trichomycterus areolatus Valenciennes, 1846 is a small endemic catfish inhabiting the Andean river basins of Chile. In this study, the morphological variability of three T. areolatus populations, collected in two river basins from southern Chile, was assessed with multivariate analyses, including principal component analysis (PCA and discriminant function analysis (DFA. It is hypothesized that populations must segregate morphologically from each other based on the river basin that they were sampled from, since each basin presents relatively particular hydrological characteristics. Significant morphological differences among the three populations were found with PCA (ANOSIM test, r = 0.552, p < 0.0001 and DFA (Wilks’s λ = 0.036, p < 0.01. PCA accounted for a total variation of 56.16% by the first two principal components. The first Principal Component (PC1 and PC2 explained 34.72 and 21.44% of the total variation, respectively. The scatter-plot of the first two discriminant functions (DF1 on DF2 also validated the existence of three different populations. In group classification using DFA, 93.3% of the specimens were correctly-classified into their original populations. Of the total of 22 transformed truss measurements, 17 exhibited highly significant (p < 0.01 differences among populations. The data support the existence of T. areolatus morphological variation across different rivers in southern Chile, likely reflecting the geographic isolation underlying population structure of the species.

  1. Estimates of river flows, floodplain inundation and land-atmosphere feedbacks in tropical African wetlands

    Science.gov (United States)

    Dadson, Simon; Hayman, Garry; MacKellar, Neil

    2013-04-01

    The regional response of African rivers and wetlands to climate variability and change is of interest to hydrologists, meteorologists and water resource planners. Over wet surfaces, high daytime evaporation rates and suppressed sensible heat fluxes induce a shallower, moister planetary boundary layer, which affects atmospheric instability and favours the initiation of new storms. Moreover, wetlands form a key link between the hydrological and carbon cycles, via anoxic degradation of organic matter to release methane (CH4). Wetlands are the largest, but least well quantified, single source of CH4, with emissions ranging from 105-278 Tg yr-1, approximately 75 percent of which comes from the tropics. Yet little is known about the ability of regional models to reproduce regional patterns of hydrological response to climate variability and change in Africa, and few studies have directly addressed the impact of fluvial inundation on water, energy and carbon fluxes between the atmosphere and the land surface. Here we use the Joint UK Land-Environment Simulator (JULES) land surface model to produce estimates of river flows over Africa. The hydrological component of this model comprises a probability-distributed model of soil moisture and runoff production coupled with a discrete approximation to the one-dimensional kinematic wave equation to route river water downslope. We use subgrid-resolution topographic data to derive a two-parameter frequency distribution of inundated areas for each grid box which we then employ to represent overbank inundation in the model. The model was configured at 0.5 degree resolution and driven using the WATCH Forcing Data (WFD; Weedon et al., 2011) which is based on ERA-40 reanalysis data and an alternative based on applying the WFD methodology to ERA-Interim data (WFDEI; Weedon et al., 2012). The model reproduces the salient features of the observed river flow and inundation patterns; these include substantial evaporative losses from

  2. African languages — is the writing on the screen? | Bosch | Southern ...

    African Journals Online (AJOL)

    The trends emerging in the natural language processing (NLP) of African languages spoken in South Africa, are explored in order to determine whether research in and development of such NLP is keeping abreast of international developments. This is done by investigating the past, present and future of NLP of African ...

  3. Detecting changes in extreme precipitation and extreme streamflow in the Dongjiang River Basin in southern China

    Science.gov (United States)

    Wang, W.; Chen, X.; Shi, P.; van Gelder, P. H. A. J. M.

    2008-02-01

    Extreme hydro-meteorological events have become the focus of more and more studies in the last decade. Due to the complexity of the spatial pattern of changes in precipitation processes, it is still hard to establish a clear view of how precipitation has changed and how it will change in the future. In the present study, changes in extreme precipitation and streamflow processes in the Dongjiang River Basin in southern China are investigated with several nonparametric methods, including one method (Mann-Kendall test) for detecting trend, and three methods (Kolmogorov-Smirnov test, Levene's test and quantile test) for detecting changes in probability distribution. It was shown that little change is observed in annual extreme precipitation in terms of various indices, but some significant changes are found in the precipitation processes on a monthly basis, which indicates that when detecting climate changes, besides annual indices, seasonal variations in extreme events should be considered as well. Despite of little change in annual extreme precipitation series, significant changes are detected in several annual extreme flood flow and low-flow series, mainly at the stations along the main channel of Dongjiang River, which are affected significantly by the operation of several major reservoirs. To assess the reliability of the results, the power of three non-parametric methods are assessed by Monte Carlo simulation. The simulation results show that, while all three methods work well for detecting changes in two groups of data with large sample size (e.g., over 200 points in each group) and large differences in distribution parameters (e.g., over 100% increase of scale parameter in Gamma distribution), none of them are powerful enough for small data sets (e.g., less than 100 points) and small distribution parameter difference (e.g., 50% increase of scale parameter in Gamma distribution). The result of the present study raises the concern of the robustness of statistical

  4. Extreme precipitation and extreme streamflow in the Dongjiang River Basin in southern China

    Science.gov (United States)

    Wang, W.; Chen, X.; Shi, P.; van Gelder, P. H. A. J. M.; Corzo, G.

    2007-07-01

    Extreme hydro-meteorological events have become the focus of more and more studies in the last decade. Due to the complexity of the spatial pattern of changes in precipitation processes, it is still hard to establish a clear view of how precipitation has changed and how it will change in the future. In the present study, changes in extreme precipitation and streamflow processes in the Dongjiang River Basin in southern China are investigated. It was shown that little change is observed in annual extreme precipitation in terms of various indices, but some significant changes are found in the precipitation processes on a monthly basis. The result indicates that when detecting climate changes, besides annual indices, seasonal variations in extreme events should be considered as well. Despite of little change in annual extreme precipitation series, significant changes are detected in several annual extreme flood flow and low-flow series, mainly at the stations along the main channel of Dongjiang River, which are affected significantly by the operation of several major reservoirs. The result highlights the importance of evaluating the impacts of human activities in assessing the changes of extreme streamflows. In addition, three non-parametric methods that are not-commonly used by hydro-meteorology community, i.e., Kolmogorov-Smirnov test, Levene's test and quantile test, are introduced and assessed by Monte Carlo simulation in the present study to test for changes in the distribution, variance and the shift of tails of different groups of dataset. Monte Carlo simulation result shows that, while all three methods work well for detecting changes in two groups of data with large data size (e.g., over 200 points in each group) and big difference in distribution parameters (e.g., over 100% increase of scale parameter in Gamma distribution), none of them are powerful enough for small data sets (e.g., less than 100 points) and small distribution parameter difference (e.g., 50

  5. Detecting changes in extreme precipitation and extreme streamflow in the Dongjiang River Basin in southern China

    Directory of Open Access Journals (Sweden)

    W. Wang

    2008-02-01

    Full Text Available Extreme hydro-meteorological events have become the focus of more and more studies in the last decade. Due to the complexity of the spatial pattern of changes in precipitation processes, it is still hard to establish a clear view of how precipitation has changed and how it will change in the future. In the present study, changes in extreme precipitation and streamflow processes in the Dongjiang River Basin in southern China are investigated with several nonparametric methods, including one method (Mann-Kendall test for detecting trend, and three methods (Kolmogorov–Smirnov test, Levene's test and quantile test for detecting changes in probability distribution. It was shown that little change is observed in annual extreme precipitation in terms of various indices, but some significant changes are found in the precipitation processes on a monthly basis, which indicates that when detecting climate changes, besides annual indices, seasonal variations in extreme events should be considered as well. Despite of little change in annual extreme precipitation series, significant changes are detected in several annual extreme flood flow and low-flow series, mainly at the stations along the main channel of Dongjiang River, which are affected significantly by the operation of several major reservoirs. To assess the reliability of the results, the power of three non-parametric methods are assessed by Monte Carlo simulation. The simulation results show that, while all three methods work well for detecting changes in two groups of data with large sample size (e.g., over 200 points in each group and large differences in distribution parameters (e.g., over 100% increase of scale parameter in Gamma distribution, none of them are powerful enough for small data sets (e.g., less than 100 points and small distribution parameter difference (e.g., 50% increase of scale parameter in Gamma distribution. The result of the present study raises the concern of the

  6. Invasive, naturalized and casual alien plants in southern Africa: a sum­mary based on the Southern African Plant Invaders Atlas (SAPIA

    Directory of Open Access Journals (Sweden)

    L. Henderson

    2007-08-01

    Full Text Available The primary objective of this publication is to provide an overview of the species identity, invasion status, geographical extent, and abundance of alien plants in South Africa, Swaziland and Lesotho, based on field records from 1979 to the end of 2000. The dataset is all the species records for the study area in the Southern African Plant Invaders Atlas (SAPIA database during this time period. A total of 548 naturalized and casual alien plant species were catalogued and invasion was recorded almost throughout the study area. Most invasion, in terms of both species numbers and total species abundance, was recorded along the southern, southwestern and eastern coastal belts and in the adjacent interior. This area includes the whole of the Fynbos and Forest Biomes, and the moister eastern parts of the Grassland and Savanna Biomes. This study reinforces previous studies that the Fynbos Biome is the most extensively invaded vegetation type in South Africa but it also shows that parts of Savanna and Grassland are as heavily invaded as parts of the Fynbos. The Fabaceae is prominent in all biomes and Acacia with 17 listed species, accounts for a very large proportion of all invasion. Acacia mearmii was by far the most prominent invasive species in the study area, followed by A. saligna, Lantana camara, A. cyclops, Opuntia ficus-indica. Solarium mauritianum, Populus alba/xcanescens, Melia azedarach, A. dealbata and species of Prosopis.

  7. Invasive, naturalized and casual alien plants in southern Africa: a sum­mary based on the Southern African Plant Invaders Atlas (SAPIA

    Directory of Open Access Journals (Sweden)

    L. Henderson

    2007-12-01

    Full Text Available The primary objective of this publication is to provide an overview of the species identity, invasion status, geographical extent, and abundance of alien plants in South Africa, Swaziland and Lesotho, based on field records from 1979 to the end of 2000. The dataset is all the species records for the study area in the Southern African Plant Invaders Atlas (SAPIA database during this time period. A total of 548 naturalized and casual alien plant species were catalogued and invasion was recorded almost throughout the study area. Most invasion, in terms of both species numbers and total species abundance, was recorded along the southern, southwestern and eastern coastal belts and in the adjacent interior. This area includes the whole of the Fynbos and Forest Biomes, and the moister eastern parts of the Grassland and Savanna Biomes. This study reinforces previous studies that the Fynbos Biome is the most extensively invaded vegetation type in South Africa but it also shows that parts of Savanna and Grassland are as heavily invaded as parts of the Fynbos. The Fabaceae is prominent in all biomes and Acacia with 17 listed species, accounts for a very large proportion of all invasion. Acacia mearmii was by far the most prominent invasive species in the study area, followed by A. saligna, Lantana camara, A. cyclops, Opuntia ficus-indica. Solarium mauritianum, Populus alba/xcanescens, Melia azedarach, A. dealbata and species of Prosopis.

  8. Fourier analysis of temporal NDVI in the Southern African and American continents

    NARCIS (Netherlands)

    Azzali, S.; Menenti, M.

    1996-01-01

    Results of applying Fourier analysis of temporal NDVI in southern Africa and southern America are summarized. The decomposition of complex time series of images in simpler periodic components by Fourier analysis allowed the factors that affect the vegetation cover to be analysed much easier. The

  9. 76 FR 34859 - Safety Zone; Augusta Southern Nationals Drag Boat Race, Savannah River, Augusta, GA

    Science.gov (United States)

    2011-06-15

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Augusta Southern Nationals Drag Boat Race... during the Augusta Southern Nationals Drag Boat Race. The Augusta Southern Nationals Drag Boat Race will consist of a series of high-speed boat races. The event is scheduled to take place from Thursday, July 14...

  10. Late Quaternary glaciation of the Upper Soca River Region (Southern Julian Alps, NW Slovenia)

    Science.gov (United States)

    Bavec, Milos; Tulaczyk, Slawek M.; Mahan, Shannon; Stock, Gregory M.

    2004-01-01

    Extent of Late Quaternary glaciers in the Upper Soc??a River Region (Southern Julian Alps, SE Europe) has been analyzed using a combination of geological mapping, glaciological modeling, and sediment dating (radiocarbon, U/Th series and Infrared Stimulated Luminescence-IRSL). Field investigations focused mainly on relatively well preserved Quaternary sequences in the Bovec Basin, an intramontane basin located SW of the Mediterranean/Black Sea divide and surrounded by mountain peaks reaching from approximately 2100 up to 2587 m a.s.l. Within the Basin we recognized two Late Quaternary sedimentary assemblages, which consist of the same facies association of diamictons, laminated lacustrine deposits and sorted fluvial sediments. Radiocarbon dating of the upper part of the lake sediments sequence (between 12790??85 and 5885??60 14C years b.p.) indicates that the younger sedimentary assemblage was deposited during the last glacial maximum and through early Holocene (Marine Isotope Stage 21, MIS 2-1). Sediment ages obtained for the older assemblage with U/Th and IRSL techniques (between 154.74??22.88 and 129.93??7.90 ka b.p. for selected samples) have large errors but both methods yield results consistent with deposition during the penultimate glacial-interglacial transition (MIS 6-5). Based on analyses of field data combined with glaciological modeling, we argue that both sediment complexes formed due to high sediment productivity spurred by paraglacial conditions with glaciers present in the uplands around the Bovec Basin but not extending down to the basin floor. Our study shows that the extent and intensity of direct glacial sedimentation by Late Quaternary glaciers in the region was previously significantly overestimated. ?? 2004 Elsevier B.V. All rights reserved.

  11. THE PARADOX OF MIGRATION AND THE INTERESTS OF THE ATOMISTIC NATION-STATES: THE SOUTHERN AFRICAN PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Phazha Jimmy Ngandwe

    2013-04-01

    Full Text Available The "paradox of migration and the interests of the atomistic nation-states" interrogates the phenomenon of migration in general and in the Southern African Development Community in particular. The point of departure of the paper is the African Union and the Southern African Development Community’s legal framework on migration, as read with the national legal instruments of the different member states. Its focal point is the raison d’être of this phenomenon of migration and the corresponding approaches and attitudes of the nation-states within which migration takes place inter se. This includes the psycho-social impact of migration. Internationally as well as regionally, States are concerned with issues of sovereignty, the preservation of the welfare of the citizenry, ensuring social cohesion social, cultural and economic development including job creation, and fighting against transnational organised crime, including terrorism. The theme of the paper is that whereas migration should form the bedrock of regionalism and globalisation, the negative attitudes of the nation-states to migration are more often than not at variance with the objectives of regionalism and globalisation. The central question of the research is how states can discharge their duties and obligations vis-à-vis their nationals without perpetuating the bottlenecks to and the stigma that attaches to migration and thereby upsetting the international as well as regional integration objectives of the free movement of people. This is the issue that the paper is intended to explore. The main areas of concern are that the negative attitudes of the nation-states are manifested in the hostile treatment of migrants at all ports of entry, including illegal or ungazetted points of entry, within the nation-states in general, and in their labour markets in particular. This research therefore explores the paradoxical nature of the duties and responsibilities of states within the

  12. Diatom species composition of the Nišava river and its tributaries Jerma and Temska rivers (southern Serbia

    Directory of Open Access Journals (Sweden)

    Andrejić Jelena Z.

    2012-01-01

    Full Text Available The main objective of this paper is to report the diatom taxa identified from the Nišava River and its tributaries, the Jerma and Temska rivers. The study area included 11 sampling sites along the Nišava River, with one site on the Jerma River and one on the Temska River. Monthly samples (from stones, sediments and macrophytes were collected from May 2008 to May 2009. Diatom frustules were cleaned with chemical agents, and mounted on permanent slides. In total, 194 diatom taxa were identified. The most species rich genera are Navicula (25, Nitzschia (17 and Gomphonema (13, while other genera are presented with one or more species. Detailed floristic analysis of the benthic diatom flora has not been conducted before on these rivers. Therefore, this paper provides a baseline for future research. [Acknowledgments. The work was supported by projects Nos. TR037009, III43002 and III45012 that are financed by the Ministry of Education and Science of the Republic of Serbia.

  13. Discriminant analysis for characterization of hydrochemistry of two mountain river basins of contrasting climates in the southern Western Ghats, India.

    Science.gov (United States)

    Thomas, Jobin; Joseph, Sabu; Thrivikramji, K P

    2015-06-01

    Discriminant analysis (DA) was performed on river hydrochemistry data for three seasons (i.e., monsoon (MON), post-monsoon (POM), and pre-monsoon (PRM)) to examine the spatio-temporal hydrochemical variability of two mountain river basins (Muthirapuzha River Basin (MRB) and Pambar River Basin (PRB)) of the southern Western Ghats, India. Although the river basins drain tropical mountainous terrain, climate and degree of anthropogenic disturbances show significant differences (i.e., humid, more disturbed MRB vs semiarid, less disturbed PRB). In MRB, TDS, Na(+), pH, Mg(2+), and K(+) are the attributes responsible for significant hydrochemical variations between the seasons, while Cl(-), TH, and Na(+) are the predictors in PRB. The temporal discriminant models imply the importance of rainfall pattern, relative contribution of groundwater toward stream discharge and farming activities in hydrochemistry between the seasons. Inclusion of hydrochemical attributes (in the temporal discriminant functions) that can be derived from both natural and anthropogenic sources suggests that ionic enrichment strongly depends on the seasons, and is mainly due to the variability in the intensity of anthropogenic activities as well as fluctuations in river discharge. In spatial discriminant models, Cl(-) is the only variable responsible for hydrochemical variations between the basins (during MON), whereas Si discriminates during POM and PRM, implying the role of atmospheric supply, anthropogenic modifications as well as intensity of weathering. In the spatial discrimination models, misclassification of hydrochemistry data between MRB and PRB can be attributed to the overlapping effect of humid climate of MRB extending toward the upstream of (semiarid) PRB. This study underscores the versatility of DA in deciphering the significance of climatic controls on hydrochemical composition of tropical mountain rivers.

  14. MODERN TENDENCIES OF CLIMATE, WATER RESOURCES AND ECOSYSTEMS CHANGES IN THE MIDDLE-LOWER PART OF SOUTHERN BUG RIVER, UKRAINE

    Directory of Open Access Journals (Sweden)

    Svitlana Boychenko

    2017-11-01

    Full Text Available Purpose: Analyze the features of climate and water regime change in the northwestern part of the Southern Bug River basin in second half of the 20th century and at the beginning of the XXI century in the region of the South-Ukrainian Nuclear Power Plant (SUNPP. Assess the impact of the SUNPP on the microclimatic conditions and identify possible threats to the biotic diversity of natural ecosystems which are associated with environmental changes. Methods: The main results of work are obtained on the basis of empirical materials by statistical analysis and analytical review of published materials. Results: The energy production at the SUNPP requires significant amount of water from Southern Bug River for cooling. Due to the climatic changes, namely, with the increase of the average annual air temperature and the decrease the amount of precipitation (in the upper and middle part of the river, the operations of the connected with cooling became complicated. Discussion: The SUNPP activity in the modern limits already have a negative impact on the environment, but the concern of ecologists is exacerbated by the possible increase of the Oleksandrivske reservoir to a mark of +20 m, which will increase the load on natural ecosystems and the society, and will violate the number of international and national legal acts, while not taking into account current trends of climate change.

  15. Environmental risk assessment in five rivers of Parana River basin, Southern Brazil, through biomarkers in Astyanax spp.

    Science.gov (United States)

    Barros, Ivaldete Tijolin; Ceccon, Juliana Parolin; Glinski, Andressa; Liebel, Samuel; Grötzner, Sonia Regina; Randi, Marco Antonio Ferreira; Benedito, Evanilde; Ortolani-Machado, Claudia Feijó; Filipak Neto, Francisco; de Oliveira Ribeiro, Ciro Alberto

    2017-07-01

    In the current study, water quality of five river sites in Parana River basin (Brazil), utilized for public water supply, was assessed through a set of biomarkers in fish Astyanax spp. Population growth and inadequate use of land are challenges to the preservation of biodiversity and resources such as water. Some physicochemical parameters as well as somatic indexes, gills and liver histopathology, genotoxicity, and biochemical biomarkers were evaluated. The highest gonadosomatic index (GSI) and antioxidant parameters (catalase and glutathione S-transferase activities, non-protein thiols), as well as the lowest damage to biomolecules (lipid peroxidation, protein carbonylation, DNA damage) were observed in site 0 (Piava River), which is located at an environmental protected area. Site 1, located in the same river, but downstream site 0 and outside the protection area, presents some level of impact. Fish from site 2 (Antas River), which lack of riparian forest and suffer from silting, presented the highest micronucleus incidence and no melanomacrophages. Differently, individuals from site 3 (Xambrê River) and site 4 (Pinhalzinho River) which receive surface runoff from Umuarama city, urban and industrial sewage, have the highest incidences of liver and gill histopathological alterations, including neoplasia, which indicated the worst health conditions of all sites. In particular, site 4 had high levels of total nitrogen and ammonia, high turbidity, and very low oxygen levels, which indicate important chemical impact. Comparison of the biomarkers in fish allowed classification of the five sites in terms of environmental impact and revealed that sites 3 and 4 had particular poor water quality.

  16. Reconnaissance of the Manistee River, a cold-water river in the northwestern part of Michigan's Southern Peninsula

    Science.gov (United States)

    Hendrickson, G.E.; Doonan, C.J.

    1972-01-01

    The cold-water streams of the northern states provide unique recreational values to the American people (wilderness or semi-wilderness atmosphere, fast-water canoeing, trout fishing), but expanding recreational needs must be balanced against the growing demand of water for public and industrial supplies, irrigation, and dilution of sewage and other wastes. In order to make intelligent decisions regarding use and management of water resources for recreation and other demands, an analysis of hydrologic factors related to recreation is essential.The Manistee River is one of Michigan's well-known trout streams-a stream having numerous public access sites and campgrounds. Upstream from Cameron Bridge (see location map) the Manistee is rated as a first-class trout stream but below Cameron Bridge the river is rated only as a fair trout stream by the Michigan Department of Natural Resources. As a Michigan canoe trail it is second only to the Au Sable River in popularity. Esthetically, the Manistee is one of Michigan's most attractive rivers, its waters flowing cool and clean, and around each bend a pleasant wilderness scene. This report deals with that part of the river upstream from State Highway M-66 at Smithville. Several hard-surface roads give access to the upper river as shown on the location map. Numerous dirt roads and trails give access to the river at intermediate points. The recreational values of the Manistee depend on its characteristics of streamflow, water quality, and bed and banks. This atlas describes these characteristics and shows how they relate to recreational use.Much of the information presented here was obtained from basic records of the U.S. Geological Survey's Water Resources Division. Additional information was obtained from field reconnaissance surveys in 1968 and 1969. The study was made in cooperation with the Michigan Geological Survey, Gerald E. Eddy, Chief. Assistance was also obtained from other sections of the Michigan Department of

  17. Validation of satellite-based precipitation estimates over different African River Basins

    Science.gov (United States)

    Thiemig, V.; Rojas, R.; Levizzani, V.; De Roo, A.

    2012-04-01

    Satellite-based precipitation products have become increasingly available and accessible in near real-time, encouraging the scientific community increasingly to use these data to replace or supplement sparse ground observations. Six satellite-based rainfall estimates (SRFE), namely, CMORPH, RFE 2.0, TRMM 3B42, GPROF 6.0, PERSIANN, GSMaP-MKV, and one reanalysis product (ERA-interim) are validated against rain gauge data over four partly sparsely-gauged African river basins (Zambezi, Volta, Juba-Shabelle and Baro-Akobo). The objective is to provide the scientific community using SRFE as input data for hydro-meteorological applications an intercomparable validation study of these products over different hydro-climatological conditions in Africa. The validation focuses on the general ability of the SRFE products to reproduce daily and monthly rainfall and, particularly, on rainfall characteristics that are relevant to hydro-meteorological applications, such as, annual catchment totals, spatial distribution pattern within the river basin, seasonality of precipitation, number of rainy days per year, and timing and amount of heavy rainfall events. The accuracy of those products is assessed using a ground observation network, comprising of 203 stations with daily records between 2003 and 2006 (data coverage: 75 % of data for 38, 13, 18 and 31 % of stations, respectively). Considering the time and space variability of the different rainfall characteristics as well as the conventional hydrological working units, the validation is done on three spatially-aggregated levels: point, subcatchment, and river basin. For the latter two the ground observations are interpolated using Kriging with External Drift, where the drift is defined as the terrain elevation. The performance is measured using standard statistical measures (MAE, RMSE, pBIAS, r, and NSeff) as well as visual inspection. The examined products showed depending on the spatially-aggregated level they have been analyzed

  18. U Pb dating of plutonic rocks involved in the nappe tectonic in southern Cameroon: consequence for the Pan-African orogenic evolution of the central African fold belt

    Science.gov (United States)

    Toteu, Sadrack Felix; Fouateu, Rose Yongue; Penaye, Joseph; Tchakounte, Jacqueline; Mouangue, Aubin Ciriaque Seme; Van Schmus, William Randall; Deloule, Etienne; Stendal, Henrik

    2006-04-01

    TIMS-ID and SIMS U-Pb dating on zircons from metaplutonic rocks involved in the Pan-African nappe of southern Cameroon allow definition of three groups of subduction-related intrusions: group-I intrusions represented by the Masins metagabbro in the Lomie region yielded 666 ± 26 Ma; group-II intrusions represented by the Mamb metasyenogabbro and the Yaoundé pyriclasite yielded ca. 620 Ma and are broadly coeval with the deposition of the Yaoundé metasediments; group-III intrusions represented by the Elon augen metagranite and the Ngaa Mbappe metamonzodiorite yielded ca. 600 Ma. The onset of the nappe tectonics occurred under high-grade conditions in the range 616 to 610 Ma and continued around 600 Ma with the emplacement of the shallowest nappes. Finally, the construction of southern Cameroon proceeded by a multi-stage evolution characterized by a long-lived development of magmatic arcs associated with rapid opening and closure of sedimentary marginal basins in relation to a northward subduction.

  19. Relationships between recent channel adjustments, present morphological state and river corridor vegetation in the Fortore River (southern Italy)

    Science.gov (United States)

    Rosskopf, Carmen Maria; Scorpio, Vittoria; Calabrese, Valentina; Frate, Ludovico; Loy, Anna; Stanisci, Angela

    2017-04-01

    The Fortore River, as many other rivers in Italy, has experienced huge channel adjustments during the last 60 years that were mainly caused by anthropic interventions, especially in-channel mining and the closure of the Occhito dam in 1966. Such changes deeply modified extension and morphological characteristics of the river corridor and, consequently, also its ecological features. The present study aims to better understand the relationships between channel adjustments and river corridor vegetation changes and those between morphological features and environmental quality of the present-day river corridor. The study has been carried out by means of a multi-temporal GIS analysis of topographic maps and aerial photographs integrated with topographic, geomorphological and ecological field surveys. Results highlight that channel adjustments occurred through two distinct phases. Most of the channel changes occurred from the 1950s until the end of the 1990s (phase 1) and led to an overall channel narrowing (from 81 to 96%) and channel bed lowering (1-4 m). These changes were accompanied by pattern shifts from multithread to single-thread configurations. The reaches located downstream of the Occhito dam were affected by more intense modifications, especially channel narrowing, with respect to upstream reaches. From 2000 to 2016 (phase 2), a trend inversion occurred. Downstream reaches remained essentially stable, while upstream reaches were affected even by some channel widening and bed aggradation and slight increase of the extension of floodplain areas giving more space to the potential development of the riparian vegetation. The evolution and the present geomorphological conditions of the river corridor are also reflected by the state of the riparian vegetation. Upstream reaches are characterized by a higher richness in riparian vegetation types and vegetation cover with respect to downstream reaches. Best conditions occur especially in the upper Fortore valley. In

  20. Delineation of erosion classes in semi-arid southern African grasslands using vegetation indices from optical remote sensing data

    Science.gov (United States)

    Hochschild, Volker; Märker, Michael; Rodolfi, Giuliano; Staudenrausch, Helmut

    2003-04-01

    As stated by many authors in the recent past, soil erosion is one of the major environmental problems in southern Africa and it will become even more severe in the future due to population growth and potential climatic changes. This study concerns the detection of different land degradation stages in semi-arid grassland areas in the upper Mbuluzi-river catchment (Kingdom of Swaziland). It has been carried out within the framework of an interdisciplinary EU-funded project aimed at developing an integrated water resources management system (IWRMS) for water resources analyses and prognostic scenario planning in semi-arid catchments of Southern Africa (Flügel et al., [2001] URL: http://www.iwrms.uni-jena.de/download/Eu-reports/report_final.pdf). Within this more general framework, particular attention was focused on the determination of high-resolution morphometric parameters for detailed erosion process studies, as well as on the derivation of relationships between vegetation cover and bare soil. The latter has subsequently been used to delineate the vegetation cover density and C-factor values for erosion models such as the revised universal soil loss equation. The examples from Southern Africa show that the methods applied are able to identify areas affected by different types of erosion. Furthermore, it is possible to estimate the parameters for a subsequent erosion modelling.

  1. Techniques of remote sensing and GIS as tools for visualizing impact of climate change-induced flood in the southern African region.

    Science.gov (United States)

    This study employs remote sensing and Geographical Information Systems (GIS) data to visualize the impact of climate change caused by flooding in the Southern African region in order to assist decision makers’ plans for future occurrences. In pursuit of this objective, this study uses Digital Elevat...

  2. Sugar Cane: A Bitter-Sweet Legacy. A Study of the Disappearing African-American Worker on the Sugar Cane Plantations in Southern Louisiana.

    Science.gov (United States)

    Jones, John A., Jr.; And Others

    This resource/study guide is designed to accompany the instructional video, "Sugar Cane: A Bitter-Sweet Legacy," which explores the significance of cultivating, harvesting, and refining sugar cane. It is also a brief study of the disappearing African-American workers on the sugar cane plantations in southern Louisiana. Seven main ideas…

  3. Identifying sources of acidity and spatial distribution of acid sulfate soils in the Anglesea River catchment, southern Australia

    Science.gov (United States)

    Wong, Vanessa; Yau, Chin; Kennedy, David

    2015-04-01

    Globally, coastal and estuarine floodplains are frequently underlain by sulfidic sediments. When exposed to oxygen, sulfidic sediments oxidise to form acid sulfate soils, adversely impacting on floodplain health and adjacent aquatic ecoystems. In eastern Australia, our understanding of the formation of these coastal and estuarine floodplains, and hence, spatial distribution of acid sulfate soils, is relatively well established. These soils have largely formed as a result of sedimentation of coastal river valleys approximately 6000 years BP when sea levels were one to two metres higher. However, our understanding of the evolution of estuarine systems and acid sulfate soil formation, and hence, distribution, in southern Australia remains limited. The Anglesea River, in southern Australia, is subjected to frequent episodes of poor water quality and low pH resulting in closure of the river and, in extreme cases, large fish kill events. This region is heavily reliant on tourism and host to a number of iconic features, including the Great Ocean Road and Twelve Apostles. Poor water quality has been linked to acid leakage from mining activities and Tertiary-aged coal seams, peat swamps and acid sulfate soils in the region. However, our understanding of the sources of acidity and distribution of acid sulfate soils in this region remains poor. In this study, four sites on the Anglesea River floodplain were sampled, representative of the main vegetation communities. Peat swamps and intertidal marshes were both significant sources of acidity on the floodplain in the lower catchment. However, acid neutralising capacity provided by carbonate sands suggests that there are additional sources of acidity higher in the catchment. This pilot study has highlighted the complexity in the links between the floodplain, upper catchment and waterways with further research required to understand these links for targeted acid management strategies.

  4. Early and abrupt retreat of the Laurentide Ice Sheet margin from the Mackenzie River valley, southern Northwest Territories

    Science.gov (United States)

    Margold, Martin; Froese, Duane G.; Gosse, John C.; Yang, Guang; McKenna, Jillian; Hidy, Alan J.

    2017-04-01

    The detachment of the Laurentide Ice Sheet margin from the Canadian Cordillera opened the present-day drainage route of the Mackenzie River to the Arctic Ocean and an ice-free corridor that allowed for migration of species between Beringia and the mid-latitudes of North America. The existing ice-margin chronology depicts the southern reach of the Mackenzie River between 61 and 63° N as glaciated until about 13 ka, representing the last portion of the Laurentide Ice Sheet margin abutting the eastern foot of the Cordillera. A substantial retreat of the ice sheet margin in this region has been suggested to have occurred during the subsequent Younger Dryas cold period, despite the fact that in many other regions ice masses stabilised or even re-grew at this time. However, until now, deglacial chronometry for this region and the western LIS margin is sparse and consists mostly of minimum-limiting macrofossil and bulk C-14 ages from organics materials overlying glacial sediment. With the aim to bring new data on the deglaciation history of the Mackenzie River valley, we collected samples for Be-10 exposure dating from glacial erratic boulders in the southern Franklin Mountains that bound the Mackenzie River valley from the east. The sampling elevations ranged between 1480 and 800 m a.s.l., however, the measured ages show only a weak correlation with elevation. Instead, 10 out of 12 measured samples cluster tightly around 15 ka, with the remaining two samples likely containing Be-10 inherited from previous periods of exposure. Our results thus indicate a pre-Younger Dryas rapid down-wasting of the ice sheet surface, which we infer was accompanied by an ice margin retreat to the southeast. The southern reach of the Mackenzie River valley at the eastern foot of the Cordillera was, according to our results, ice free shortly after 15 ka, with the prospect that the ice-free corridor might have opened significantly earlier than hitherto anticipated. Further research is

  5. Southern African Treatment Resistance Network (SATuRN) RegaDB HIV drug resistance and clinical management database: supporting patient management, surveillance and research in southern Africa.

    Science.gov (United States)

    Manasa, Justen; Lessells, Richard; Rossouw, Theresa; Naidu, Kevindra; Van Vuuren, Cloete; Goedhals, Dominique; van Zyl, Gert; Bester, Armand; Skingsley, Andrew; Stott, Katharine; Danaviah, Siva; Chetty, Terusha; Singh, Lavanya; Moodley, Pravi; Iwuji, Collins; McGrath, Nuala; Seebregts, Christopher J; de Oliveira, Tulio

    2014-01-01

    Substantial amounts of data have been generated from patient management and academic exercises designed to better understand the human immunodeficiency virus (HIV) epidemic and design interventions to control it. A number of specialized databases have been designed to manage huge data sets from HIV cohort, vaccine, host genomic and drug resistance studies. Besides databases from cohort studies, most of the online databases contain limited curated data and are thus sequence repositories. HIV drug resistance has been shown to have a great potential to derail the progress made thus far through antiretroviral therapy. Thus, a lot of resources have been invested in generating drug resistance data for patient management and surveillance purposes. Unfortunately, most of the data currently available relate to subtype B even though >60% of the epidemic is caused by HIV-1 subtype C. A consortium of clinicians, scientists, public health experts and policy markers working in southern Africa came together and formed a network, the Southern African Treatment and Resistance Network (SATuRN), with the aim of increasing curated HIV-1 subtype C and tuberculosis drug resistance data. This article describes the HIV-1 data curation process using the SATuRN Rega database. The data curation is a manual and time-consuming process done by clinical, laboratory and data curation specialists. Access to the highly curated data sets is through applications that are reviewed by the SATuRN executive committee. Examples of research outputs from the analysis of the curated data include trends in the level of transmitted drug resistance in South Africa, analysis of the levels of acquired resistance among patients failing therapy and factors associated with the absence of genotypic evidence of drug resistance among patients failing therapy. All these studies have been important for informing first- and second-line therapy. This database is a free password-protected open source database available on

  6. Future ecosystem services in a Southern African river basin: a scenario planning approach to uncertainty

    CSIR Research Space (South Africa)

    Bohensky, EL

    2006-08-01

    Full Text Available Scenario planning is a promising tool for dealing with uncertainty, but it has been underutilized in ecology and conservation. The use of scenarios to explore ecological dynamics of alternative futures has been given a major boost by the recently...

  7. Book Review | Lupton-Smith | Southern African Journal of Critical Care

    African Journals Online (AJOL)

    Cardiopulmonary Physiotherapy in Trauma: An Evidence-based Approach Edited by Heleen van Aswegen and Brenda Morrow. London: Imperial College Press, 2015. ISBN 978-1-78326-651-7. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African ...

  8. Southern African Journal of HIV Medicine - Vol 19, No 1 (2018)

    African Journals Online (AJOL)

    'Scared of going to the clinic': Contextualising healthcare access for men who have sex with men, female sex workers and people who use drugs in two South African cities · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Zoe Duby, Busisiwe Nkosi, Andrew Scheibe, ...

  9. Low-flow anaesthesia (how to do it) | Welch | Southern African ...

    African Journals Online (AJOL)

    The introduction of Desflurane and Sevoflurane in the South African market over the past few years, along with the 0028 code for lowflow earlier this year has renewed interest in the technique. Some anaesthesia machines now come equipped with “econometers” designed to achieve the optimal fresh gas flow, while also ...

  10. New taxa, new records and name changes for southern African plants

    Directory of Open Access Journals (Sweden)

    B. C. de Wet

    1989-12-01

    Full Text Available Alterations to the inventory of about 24 000 species and infraspecific taxa of bryophytes and vascular plants in southern Africa are reported for the year 1988. The inventory, as currently maintained in the Taxon component of the PRECIS system, contains the accepted name for each taxon, synonyms previously in use as accepted names during the past half-century, and literature references necessary to identify species in each genus and to establish the synonymy. The inventory is updated as new research affecting plant classification in southern Africa is published. During 1988 there were 744 alterations, affecting about 3% of the total number of taxa.

  11. New taxa, new records and name changes for southern African plants

    Directory of Open Access Journals (Sweden)

    G. E. Gibbs Russell

    1988-12-01

    Full Text Available Alterations to the inventory of about 24 000 species and infraspecific taxa of bryophytes and vascular plants in southern Africa are reported for the year 1987. The inventory, as presently maintained in the Taxon component of the PRECIS system, contains the accepted name for each taxon, synonyms previously in use as accepted names during the past half-century, and literature references necessary to identify species in each genus and to establish the synonymy. The inventory is updated as new research affecting plant classification in southern Africa is published. During 1987 there were 678 alterations, representing about 2,8% of the total number of taxa.a

  12. Computational analysis of candidate disease genes and variants for Salt-sensitive hypertension in indigenous Southern Africans

    KAUST Repository

    Tiffin, Nicki

    2010-09-27

    Multiple factors underlie susceptibility to essential hypertension, including a significant genetic and ethnic component, and environmental effects. Blood pressure response of hypertensive individuals to salt is heterogeneous, but salt sensitivity appears more prevalent in people of indigenous African origin. The underlying genetics of salt-sensitive hypertension, however, are poorly understood. In this study, computational methods including text- and data-mining have been used to select and prioritize candidate aetiological genes for salt-sensitive hypertension. Additionally, we have compared allele frequencies and copy number variation for single nucleotide polymorphisms in candidate genes between indigenous Southern African and Caucasian populations, with the aim of identifying candidate genes with significant variability between the population groups: identifying genetic variability between population groups can exploit ethnic differences in disease prevalence to aid with prioritisation of good candidate genes. Our top-ranking candidate genes include parathyroid hormone precursor (PTH) and type-1angiotensin II receptor (AGTR1). We propose that the candidate genes identified in this study warrant further investigation as potential aetiological genes for salt-sensitive hypertension. © 2010 Tiffin et al.

  13. Suspended sediment yield and metal contamination in a river catchment affected by El Niño events and gold mining activities: the Puyango river basin, southern Ecuador

    Science.gov (United States)

    Tarras-Wahlberg, N. H.; Lane, S. N.

    2003-10-01

    The suspended sediment yield and the transfer of polluted sediment are investigated for the Puyango river basin in southern Ecuador. This river system receives metal (Cd, Cu, Hg, Pb and Zn) and cyanide pollution generated by mining, and is associated with large-scale hydrological variability, which is partly governed by El Niño events. Field sampling and statistical modelling methods are used to quantify the amount of mine tailings that is discharged into the basin. Annual suspended sediment yields are estimated using a novel combination of the suspended sediment rating method and Monte Carlo simulations, which allow for propagation of the uncertainties of the calculations that lead to final load estimates. Geochemical analysis of suspended and river bed sediment is used to assess the dispersion and long-term fate of contaminated sediment within the river catchment. Knowledge of the inter- and intra-annual variation in suspended sediment yield is shown to be crucial for judging the importance of mining discharges, and the extent to which the resultant pollution is diluted by river flows. In wet years, polluted sediments represent only a very small proportion of the yield estimates, but in dry years the proportion can be significant. Evidence shows that metal contaminated sediments are stored in the Puyango river bed during low flows. Large flood events flush this sediment periodically, both on an annual cycle associated with the rainy season, and also related to El Niño events. Therefore, environmental impacts of mining-related discharges are more likely to be severe during dry years compared with wet years, and in the dry season rather than the wet season. The hydrological consequences of El Niño events are shown to depend upon the extent to which these events penetrate inland. It is, thus, shown that the general conclusion that El Niño events can significantly affect suspended sediment yields needs evaluation with respect to the particular way in which those

  14. Challenges of transfrontier conservation areas: Natural resources nationalism, security and regionalism in the southern African development community region

    Directory of Open Access Journals (Sweden)

    Oswell Rusinga

    2012-12-01

    Full Text Available Transfrontier Conservation Areas (TFCAs initiatives in the Southern African Development Community (SADC region offer hope for providing a mechanism for resolving political tensions and conflicts which are not only related to environmental issues but to security concerns as well. The geopolitical implications of TFCAs in the SADC region cannot be overemphasised with regard to international relations and regional integration. The SADS region is characterised by histories of contested military balance of power and geopolitical rivalries which have a potential to degenerate into military confrontation. Although there is a strong belief in multilateral co-operation among SADC member countries, most of them often engage the international community at the bilateral level. Moreover, there is disharmony in constitutional applications of the rule of law, respect of human rights and good governance. However, TFCAs initiatives in Southern Africa have been seen as offering an opportunity to heal the wounds of pre- and post-independence wars of destabilisation through the encouragement of inter-state collaboration and co-operation by giving governments an opportunity for mutual action on issues of common interest.

  15. Tree cover and biomass increase in a southern African savanna despite growing elephant population

    NARCIS (Netherlands)

    Kalwij, J.M.; Boer, de W.F.; Mucina, L.; Prins, H.H.T.; Skarpe, C.; Winterbach, C.

    2010-01-01

    The growing elephant populations in many parts of southern Africa raise concerns of a detrimental loss of trees, resulting in overall reduction of biodiversity and ecosystem functioning. Elephant distribution and density can be steered through artificial waterpoints (AWPs). However, this leaves

  16. The relative contribution of sewage and diffuse phosphorus sources in the River Avon catchment, southern England: implications for nutrient management.

    Science.gov (United States)

    Bowes, Michael J; Hilton, John; Irons, Gordon P; Hornby, Duncan D

    2005-05-15

    In order to effectively manage nutrient river load reductions and target remediation strategies, it is important to determine the relative contributions of diffuse and point sources across the river catchment. This study used a geographical information system (GIS) to apply phosphorus (P) export coefficients (obtained from the literature) to 58 water quality monitoring sites across a large, urbanised, mixed land use catchment, typical of southern lowland England (the River Avon, Warwickshire, UK). These coefficients were used to estimate the annual P load at each monitoring site, and also the relative contribution of point source (from sewage treatment works (STW)) and diffuse input (from both livestock and agricultural land use). The estimated annual P loads showed very close agreement (r2=0.98) with the measured total phosphorus (TP) loads. Sites with the highest proportion of P derived from STW had the highest TP concentrations and loads, and also had greater variations between seasons, with elevated P concentrations occurring during the summer months. The GIS model was re-run to determine the effect of an 80% reduction in P output from STW serving over 10,000 people, thereby assessing the effect of implementing the European Union's Urban Waste Water Treatment Directive (UWWTD). The exported TP load was reduced by 52%, but the sites with the highest TP concentrations were still those with the highest proportion of P derived from STW. The GIS model was re-run to estimate the impact of 80% P reductions at a further 11 STW of varying sizes. This reduced the total TP load by only 29 tonnes year-1, but greatly reduced the P concentrations in many highly nutrient contaminated tributaries. The number of sites with P concentrations greater than 1 mg l-1 was cut from 15 (before UWWTD implementation) to 2. These findings suggest that after UWWTD implementation, resources should focus on introducing tertiary sewage treatment at the remaining large STW, before targeting

  17. The African buffalo: a villain for inter-species spread of infectious diseases in southern Africa.

    Science.gov (United States)

    Michel, Anita L; Bengis, Roy G

    2012-06-20

    The African buffalo (Syncerus caffer) is a large wild bovid which until recently ranged across all but the driest parts of sub-Saharan Africa, and their local range being limited to about 20 km from surface water. They are of high ecological value due to their important role as bulk feeders in the grazing hierarchy. They also have high economic value, because they are one of the sought after 'Big Five' in the eco-tourism industry. In Africa, buffaloes have been recognised for some time as an important role player in the maintenance and transmission of a variety of economically important livestock diseases at the wildlife and/or livestock interface. These include African strains of foot-and-mouth disease (FMD), Corridor disease (theileriosis), bovine tuberculosis and bovine brucellosis. For a number of other diseases of veterinary importance, African buffaloes may also serve as amplifier or incidental host, whereby infection with the causative pathogens may cause severe clinical signs such as death or abortion as in the case of anthrax and Rift Valley fever, or remain mild or subclinical for example heartwater. The long term health implications of most of those infections on the buffalo at a population level is usually limited, and they do not pose a threat on the population's survival. Because of their ability to harbour and transmit important diseases to livestock, their sustainable future in ecotourism, trade and transfrontier conservation projects become complex and costly and reliable diagnostic tools are required to monitor these infections in buffalo populations.

  18. Setting the agenda in emergency medicine in the southern African region: Conference assumptions and recommendations, Emergency Medicine Conference 2014: Gaborone, Botswana

    Directory of Open Access Journals (Sweden)

    Lloyd D. Christopher

    2014-09-01

    Full Text Available The first international emergency medicine (EM conference in Botswana was held on 15th and 16th May 2014 at the Gaborone International Convention Centre. The support from key stakeholders positioned the conference, from its conception, to deliver expert guidance on emergency medicine relevance, education and systems implementation. The conference theme was aptly: “Setting the Agenda in Emergency Medicine in the Southern African Region.” Over 300 local, regional and international delegates convened to participate in this landmark event. Country representation included Botswana, South Africa, Zambia, Namibia, Zimbabwe, Swaziland, Lesotho, Nigeria and the United States of America. Conference assumptions intersected emergency care, African burden of injury and illness and the role of the state; the public protection ethic of emergency care, and the developmental, economic and health interest in promoting EM. The recommendations addressed emergency care relevance; health systems research as an imperative for emergency systems development in southern Africa; community agency as a requisite for emergency care resilience; emergency care workers as pivotal to the emergency medical system, and support of EM system implementation. The conference recommendations – by way of setting an agenda, augur well for emergency care development and implementation in the southern African region and are likely to prove useful to the southern African countries seeking to address health service quality, EM advocacy support and implementation guidance. Emergency medicine is the only discipline with ‘universality’ and ‘responsivity’ at the point of need. This implies the widespread potential for facilitation of access to health care: a public health goal nuanced by the African development agenda.

  19. Water resources transfers through southern African food trade: water efficiency and climate signals

    Science.gov (United States)

    Dalin, Carole; Conway, Declan

    2016-01-01

    Temporal and spatial variability of precipitation in southern Africa is particularly high. The associated drought and flood risks, combined with a largely rain-fed agriculture, pose a challenge for water and food security in the region. As regional collaboration strengthens through the Southern Africa Development Community and trade with other regions increases, it is thus important to understand both how climate variability affects agricultural productivity and how food trade (regional and extra-regional) can contribute to the region's capacity to deal with climate-related shocks. We combine global hydrological model simulations with international food trade data to quantify the water resources embedded in international food trade in southern Africa and with the rest of the world, from 1986-2011. We analyze the impacts of socio-economic changes and climatic variability on agricultural trade and embedded water resources during this period. We find that regional food trade is efficient in terms of water use but may be unsustainable because water-productive exporters, like South Africa, rely on increasingly stressed water resources. The role of imports from the rest of the world in the region's food supply is important, in particular during severe droughts. This reflects how trade can efficiently redistribute water resources across continents in response to a sudden gap in food production. In a context of regional and global integration, our results highlight opportunities for improved water-efficiency and sustainability of the region's food supply via trade.

  20. Impact of river basin management on coastal water quality and ecosystem services: A southern Baltic estuary

    Science.gov (United States)

    Schernewski, Gerald; Hürdler, Jens; Neumann, Thomas; Stybel, Nardine; Venohr, Markus

    2010-05-01

    Eutrophication management is still a major challenge in the Baltic Sea region. Estuaries or coastal waters linked to large rivers cannot be managed independently. Nutrient loads into these coastal ecosystems depend on processes, utilisation, structure and management in the river basin. In practise this means that we need a large scale approach and integrated models and tools to analyse, assess and evaluate the effects of nutrient loads on coastal water quality as well as the efficiency of river basin management measures on surface waters and especially lagoons and estuaries. The Odra river basin, the Szczecin Lagoon and its coastal waters cover an area of about 150,000 km² and are an eutrophication hot-spot in the Baltic region. To be able to carry out large scale, spatially integrative analyses, we linked the river basin nutrient flux model MONERIS to the coastal 3D-hydrodynamic and ecosystem model ERGOM. Objectives were a) to analyse the eutrophication history in the river basin and the resulting functional changes in the coastal waters between early 1960's and today and b) to analyse the effects of an optimal nitrogen and phosphorus management scenario in the Oder/Odra river basin on coastal water quality. The models show that an optimal river basin management with reduced nutrient loads (e.g. N-load reduction of 35 %) would have positive effects on coastal water quality and algae biomass. The availability of nutrients, N/P ratios and processes like denitrification and nitrogen-fixation would show spatial and temporal changes. It would have positive consequences for ecosystems functions, like the nutrient retention capacity, as well. However, this optimal scenario is by far not sufficient to ensure a good coastal water quality according to the European Water Framework Directive. A "good" water quality in the river will not be sufficient to ensure a "good" water quality in the coastal waters. Further, nitrogen load reductions bear the risk of increased

  1. The African buffalo: A villain for inter-species spread of infectious diseases in southern Africa

    Directory of Open Access Journals (Sweden)

    Anita L. Michel

    2012-06-01

    Full Text Available The African buffalo (Syncerus caffer is a large wild bovid which until recently ranged across all but the driest parts of sub-Saharan Africa, and their local range being limited to about 20 km from surface water. They are of high ecological value due to their important role as bulk feeders in the grazing hierarchy. They also have high economic value, because they are one of the sought after ‘Big Five’ in the eco-tourism industry. In Africa, buffaloes have been recognised for some time as an important role player in the maintenance and transmission of a variety of economically important livestock diseases at the wildlife and/or livestock interface. These include African strains of foot-and-mouth disease (FMD, Corridor disease (theileriosis, bovine tuberculosis and bovine brucellosis. For a number of other diseases of veterinary importance, African buffaloes may also serve as amplifier or incidental host, whereby infection with the causative pathogens may cause severe clinical signs such as death or abortion as in the case of anthrax and Rift Valley fever, or remain mild or subclinical for example heartwater. The long term health implications of most of those infections on the buffalo at a population level is usually limited, and they do not pose a threat on the population’s survival. Because of their ability to harbour and transmit important diseases to livestock, their sustainable future in ecotourism, trade and transfrontier conservation projects become complex and costly and reliable diagnostic tools are required to monitor these infections in buffalo populations.

  2. Coupling effect analysis between landslides, river channel changes and sediment budgets - extreme climate events in Laishe River, southern Taiwan

    Science.gov (United States)

    Chang, Kuo-Jen; Huang, Mei-Jen; Tseng, Chih-Ming

    2016-04-01

    Taiwan, due to the high seismicity and high annual rainfall, numerous landslides triggered every year and severe impacts affect the island. Concerning to the catastrophic landslides, the key information of landslide, including range of landslide, volume estimation and the subsequent evolution are important when analyzing the triggering mechanism, hazard assessment and mitigation. Thus, the morphological analysis gives a general overview for the landslides and been considered as one of the most fundamental information. Typhoon Morakot brought extreme and long-time rainfall for Taiwan in August 2009, and caused severe disasters. In this study we integrate several technologies, especially by Unmanned Aerial Vehicle (UAV) and multi-spectral camera, to decipher the consequence and the potential hazard, and the social impact. In recent years, the remote sensing technology improves rapidly, providing a wide range of image, essential and precise information. This study integrates several methods, including, 1) Remote-sensing images gathered by Unmanned Aerial Vehicle (UAV) and by aerial photos taken in different periods; 2) field in-situ geologic investigation; 3) Differential GPS, RTK GPS geomatic measurements. The methods allow to constructing the DTMs before and after landslide, as well as the subsequent periods by using aerial photos and UAV derived images. The data sets permits to analysis the morphological changes. In the past, the study of sediment budgets usually relies on field investigation, but due to inconvenient transportation, topographical barriers, or located in remote areas, etc. the survey is hardly to be completed sometimes. In recent years, the rapid development of remote sensing technology improves image resolution and quality significantly. Remote sensing technology can provide a wide range of image data, and provide essential and precious information. The purpose of this study is to investigate the phenomenon of river migration and to evaluate the

  3. Post-Mazama Break-out Flood on the Sycan River, southern Oregon

    Science.gov (United States)

    Lind, P.; O'Connor, J. E.; McDowell, P.

    2007-12-01

    The Sycan River is the largest tributary to the Sprague River watershed in the semi-arid Upper Klamath Basin of south-central Oregon. Only 56 kilometers (35 miles) from Crater Lake, Mt Mazama's&premnant volcanic crater, the headwaters of the Sycan watershed has an abundance of aeolian and fluvially distributed Mazama pumice. The upper Sycan River flows through a wide basin 17 km long (Sycan Marsh), then southward through 40 kms of narrow basalt canyon. The lower16 river kilometers occupy a low gradient unconfined southward-widening valley at the Sprague River confluence. Field investigation of cut banks and auger holes in the lower valley reveal an extensive 1 to 2-m thick lobe-shaped deposit dominated by Mazama pumice, and fining upward from granules to medium sand. This deposit is interpreted as resulting from a single or set of break-out flood events relatively soon after the pyroclastic eruptions of Mt Mazama 7,700 years ago. The flood event buried a fine-grained floodplain with a thick layer of pumiceous sands across the river's unconfined lower valley section. In the upstream canyon section, boulder bars and boulder terraces as well as terraces of Mazama tephra indicate that the event was a relatively large system-wide flood. Distribution and stratigraphy of the resultant flood terraces of the lower Sycan River suggest that the event was a break-out flood caused by blockage in the confined canyon section. The location and mechanism of blockage are not definitely known; it may be either landslide(s) from the canyon walls, or accumulation(s) of Mazama tephra and other sediments in the canyon. Submitted radiocarbon samples from or near the base of the flood deposits will date the break-out flood event. Additional analysis and field investigation is underway to determine the mechanism and location of the canyon blockage, the hydraulic dynamics of the flood and the extent of the flood deposit lobe.

  4. Water quality assessment of the Shatt al-Arab River, Southern Iraq

    Directory of Open Access Journals (Sweden)

    Mohammad Salim Moyel

    2015-06-01

    Full Text Available Objective: To assess suitability of the water quality of Shatt al-Arab River for protection of aquatic life, potable water supply and irrigation uses. Methods: The Shatt al-Arab River was monitored on a monthly basis from July 2009 to June 2010. A water quality index (WQI was calculated to assess the suitability of water for protection of aquatic life, potable water supply and irrigation uses during the dry season from July to December 2009 and the wet season from January until June 2010. Results: The results of the WQI showed that the lowest water quality values were scored during the dry season for all three uses of the river. Marginal water quality values were recorded for protection of aquatic life and fair (upstream to poor (downstream water quality values were recorded for irrigation uses. Moreover, the river water was not suitable for potable water supply without elaborate treatment. Conclusions: Deterioration of the Shatt al-Arab water quality has been attributed to reduced freshwater discharges from Tigris and Euphrates Rivers, low annual precipitations and an advancing salt wedge from the Arabian Gulf. However, a combination of those factors such as low riverine discharge and advancing salt wedge with a continuous discharge of agriculture, oil industry and urban point effluent has polluted the waters and fostered the decline of the Shatt al-Arab River water quality during the study period. The study indicated that application of WQIs was a useful tool to monitor and assess the overall water quality of the Shatt al-Arab River.

  5. Distribution of dissolved and labile particulate trace metals in the overlying bottom water in the Vistula River plume (southern Baltic Sea)

    NARCIS (Netherlands)

    Sokolowski, A.; Wolowicz, M.; Hummel, H.

    2001-01-01

    Overlying bottom water samples were collected in the Vistula River plume, southern Baltic Sea, (Poland) and analysed for dissolved and labile particulate (1 M HCl extractable) Cu, Pb, Zn, Mn, Fe and Ni, hydrological parameters being measured simultaneously. Particulate organic matter (POM),

  6. Deconstructing southern African (multi) decadal summer rainfall variability through synoptic convection regimes

    Science.gov (United States)

    Pohl, Benjamin; Dieppois, Bastien; Crétat, Julien

    2017-04-01

    Austral summer rainfall in Southern Africa is highly variable in time and space. Seasonal rainfall amounts archived in long-term observational databases have recently been shown to exhibit significant periodicities at the interannual timescale (with a 2-8 year peak materializing mostly the regional effects of El Niño Southern Oscillation, ENSO), the quasi-decadal (8-13 years) and inter-decadal (15-28 years) timescales, interpretable as the signature of the Pacific Decadal Oscillation and Interdecadal Pacific Oscillation over the region. Here, we attempt to deconstruct these rainfall signals into a limited number of coherent synoptic convective regimes, obtained by applying a k-means clustering on daily Outgoing Longwave Radiation (OLR) derived from the 20th Century Reanalysis (20CR), on the period 1901-2010 and on the 56 ensemble members individually. Results show a time-increasing agreement between the ensemble members for capturing transient variability of large-scale atmospheric convection during the austral summer rainy season. Over the recent years, the results match well those obtained using satellite OLR measurements. The respective contribution of each regime to the three dominant timescales of rainfall variability has been assessed using multiple wavelet coherence analyses. The strong interannual teleconnections between the regional convective regimes and ENSO in the recent decades remain very robust throughout the 20th century. Synoptic convective regimes leading to wetter conditions in southern Africa are not systematically related to La Nina conditions. However, combinations of El Nino conditions at the interannual timescale with negative phases of the IPO and/or the PDO are likely to be associated with wetter conditions in southern Africa. At the quasi-decadal and inter-decadal timescales, analyses suggest a superposition of short-term anomalies associated with the various regimes and large-scale changes in convective activity. These interactions

  7. Evidence for panmixia despite barriers to gene flow in the southern African endemic, Caffrogobius caffer (Teleostei: Gobiidae

    Directory of Open Access Journals (Sweden)

    von der Heyden Sophie

    2008-12-01

    Full Text Available Abstract Background Oceanography and life-history characteristics are known to influence the genetic structure of marine species, however the relative role that these factors play in shaping phylogeographic patterns remains unresolved. The population genetic structure of the endemic, rocky shore dwelling Caffrogobius caffer was investigated across a known major oceanographic barrier, Cape Agulhas, which has previously been shown to strongly influence genetic structuring of South African rocky shore and intertidal marine organisms. Given the variable and dynamic oceanographical features of the region, we further sought to test how the pattern of gene flow between C. caffer populations is affected by the dominant Agulhas and Benguela current systems of the southern oceans. Results The variable 5' region of the mtDNA control region was amplified for 242 individuals from ten localities spanning the distributional range of C. caffer. Fifty-five haplotypes were recovered and in stark contrast to previous phylogeographic studies of South African marine species, C. caffer showed no significant population genetic structuring along 1300 km of coastline. The parsimony haplotype network, AMOVA and SAMOVA analyses revealed panmixia. Coalescent analyses reveal that gene flow in C. caffer is strongly asymmetrical and predominantly affected by the Agulhas Current. Notably, there was no gene flow between the east coast and all other populations, although all other analyses detect no significant population structure, suggesting a recent divergence. The mismatch distribution suggests that C. caffer underwent a population expansion at least 14 500 years ago. Conclusion We propose several possible life-history adaptations that could have enabled C. caffer to maintain gene flow across its distributional range, including a long pelagic larval stage. We have shown that life-history characteristics can be an important contributing factor to the phylogeography of marine

  8. The hemorrhagic fevers of Southern Africa with special reference to studies in the South African Institute for Medical Research.

    Science.gov (United States)

    Gear, J H

    1982-01-01

    In this review of studies on the hemorrhagic fevers of Southern Africa carried out in the South African Institute for Medical Research, attention has been called to occurrence of meningococcal septicemia in recruits to the mining industry and South African Army, to cases of staphylococcal and streptococcal septicemia with hemorrhagic manifestations, and to the occurrence of plague which, in its septicemic form, may cause a hemorrhagic state. "Onyalai," a bleeding disease in tropical Africa, often fatal, was related to profound thrombocytopenia possibly following administration of toxic witch doctor medicine. Spirochetal diseases, and rickettsial diseases in their severe forms, are often manifested with hemorrhagic complications. Of enterovirus infections, Coxsackie B viruses occasionally caused severe hepatitis associated with bleeding, especially in newborn babies. Cases of hemorrhagic fever presenting in February-March, 1975 are described. The first outbreak was due to Marburg virus disease and the second, which included seven fatal cases, was caused by Rift Valley fever virus. In recent cases of hemorrhagic fever a variety of infective organisms have been incriminated including bacterial infections, rickettsial diseases, and virus diseases, including Herpesvirus hominis; in one patient, the hemorrhagic state was related to rubella. A boy who died in a hemorrhagic state was found to have Congo fever; another patient who died of severe bleeding from the lungs was infected with Leptospira canicola, and two patients who developed a hemorrhagic state after a safari trip in Northern Botswana were infected with Trypanosoma rhodesiense. An illness manifested by high fever and melena developed in a young man after a visit to Zimbabwe; the patient was found to have both malaria and Marburg virus disease.

  9. Estimated bankfull discharge for selected Michigan rivers and regional hydraulic geometry curves for estimating bankfull characteristics in southern Michigan rivers

    Science.gov (United States)

    Rachol, Cynthia M.; Boley-Morse, Kristine

    2009-01-01

    Regional hydraulic geometry curves are power-function equations that relate riffle dimensions and bankfull discharge to drainage-basin size. They are defined by data collected through surveys conducted at stable stream reaches and can be used to aid watershed managers, design engineers, and others involved in determination of the best course of action for an unstable stream. Hydraulic geometry curves provide a mechanism through which comparisons can be made between riffle dimensions collected at an unstable stream to those collected at stable streams within the same region. In 2005, a study was initiated to delineate regional hydraulic geometry curves for Michigan. After in-office review of 343 U.S. Geological Survey streamgaging stations and an extensive field reconnaissance effort, 44 stable reaches were selected for this study. Detailed surveys that included cross-sectional and longitudinal profiles and pebble counts were conducted at selected streamgages, which were distributed throughout Michigan. By use of survey data from riffle cross sections and water-surface slope, bankfull discharge was estimated and compared to flood-recurrence intervals using regional flood equations. This comparison shows that bankfull discharges in Michigan recur more frequently than every 2 years. Regional hydraulic geometry curves were developed rather than statewide curves owing to large differences in factors that control channel geometry across the State. However, after the data were subdivided according to ecoregions, it was determined that there were enough data to delineate regional hydraulic geometry curves only for the Southern Lower Michigan Ecoregion. For this ecoregion, geometry curve equations and their coefficients of determination are: Width = 8.19 x DA0.44; R2 = 0.69, Depth = 0.67 x DA0.27; R2 = 0.28, Area = 4.38 x DA0.74; R2 = 0.59, where DA is the drainage area and R2 is the coefficient of determination. By use of discharge estimates for the Southern Lower Michigan

  10. Establishing the environmental flow regime for the Middle Zambezi River

    NARCIS (Netherlands)

    Mwelwa-Mutekenya-Mwelwa, E.

    2016-01-01

    The Middle Zambezi, host to a rich biodiversity, is located in the central part of the Zambezi River Basin which covers eight Southern African Countries. The area is located downstream of three hydropower schemes. In the last decades, the floodplain riparian tree, the Faidherbia albida, vital for

  11. Establishing the Environmental Flow Regime for the Middle Zambezi River

    NARCIS (Netherlands)

    Mwelwa-Mutekenya, E.

    2016-01-01

    The Middle Zambezi, host to a rich biodiversity, is located in the central part of the Zambezi River Basin which covers eight Southern African Countries. The area is located downstream of three hydropower schemes. In the last decades, the floodplain riparian tree, the Faidherbia albida, vital for

  12. Molecular characterization of Giardia duodenalis cysts in the Oreto River (Sicily, Southern Italy

    Directory of Open Access Journals (Sweden)

    Maria Antonella Di Benedetto

    2010-03-01

    Full Text Available

    Background: The presence of Giardia was investigated along the Oreto river between January 2008 and May 2009 with the aim of understanding the source of contamination by molecular typing of cysts.

    Methods: A total of 38 water samples (10 collected from the river mouth, 24 from the whole Oreto basin and 4 sewage samples from the Monreale treatment plant were processed. In addition, 22 faecal samples of livestock living close to the Oreto area, were analyzed. The presence of Giardia was determined by immunofluorescence assay and their genetic characterization was achieved by a nested PCR assay targeting the triosephosphate isomerase gene.

    Results: All water samples from the river mouth were positive for Giardia, even if the concentration of cysts fluctuated considerably among sampling occasions. Our investigation showed that the Vadduneddu and Altofonte torrents, two influents of the river, were the principal sources of contamination. Moreover, the genotypes of Vadduneddu torrent were the same as those detected in human wastewater taken from the activated sludge plant of Monreale city. Assemblages A and B were found in water samples with a predominance of Assemblage A, subtype AII. Assemblage E was only found in a single calf isolate.

    Conclusions: The data show that the high cyst counts regularly detected in the Oreto river are due to contamination with wastewater of human origin. This finding is relevant for public health, particularly because river water is used for agricultural purposes.

  13. Hydrological modeling of the semi-arid Andarax river basin in southern Spain

    DEFF Research Database (Denmark)

    Andersen, Flemming Hauge; Jensen, Karsten Høgh; Sandholt, Inge

    as this it will lead to better estimate of the groundwater recharge and hereby of the groundwater availability in the delta region.   The hydrological behaviour of the Andarax river basin is simulated by the MIKE SHE code, which is a physically based, distributed and integrated hydrological model. In the first...... scenario we only use traditional meteorological data and standard values for the vegetation characteristics. The traditional meteorological data are rather sparse for the Andarax river basin and to improve the estimation of evapotranspiration we use an energy-based two-layer SVAT model and apply remote...

  14. Impact of wet season river flood discharge on phytoplankton absorption properties in the southern Great Barrier Reef region coastal waters

    Science.gov (United States)

    Cherukuru, Nagur; Brando, Vittorio E.; Blondeau-Patissier, David; Ford, Phillip W.; Clementson, Lesley A.; Robson, Barbara J.

    2017-09-01

    Light absorption due to particulate and dissolved material plays an important role in controlling the underwater light environment and the above water reflectance signature. Thorough understanding of absorption properties and their variability is important to estimate light propagation in the water column. However, knowledge of light absorption properties in flood impacted coastal waters is limited. To address this knowledge gap we investigated a bio-optical dataset collected during a flood (2008) in the southern Great Barrier Reef (GBR) region coastal waters. Results presented here show strong impact of river flood discharges on water column stratification, distribution of suspended substances and light absorption properties in the study area. Bio-optical analysis showed phytoplankton absorption efficiency to reduce in response to increased coloured dissolved organic matter presence in flood impacted coastal waters. Biogeophysical property ranges, relationships and parametrisation presented here will help model realistic underwater light environment and optical signature in flood impacted coastal waters.

  15. The Common Agricultural Policy as a driver of water quality changes: the case of the Guadalquivir River Basin (southern Spain

    Directory of Open Access Journals (Sweden)

    Gloria Salmoral

    2015-09-01

    Full Text Available Several studies have analysed the effects of European environmental policies on water quality, but no detailed retrospective analysis of the impacts of the Common Agricultural Policy (CAP reforms on observed water quality parameters has been carried out. This study evaluates the impact of the CAP and other drivers on the concentrations of nitrates and suspended solids in the Guadalquivir River Basin (southern Spain over the 1999-2009 period. The most important drivers that are degrading both water quality indicators are exports from upland areas and agricultural intensification. Water quality conditions have improved in regions where there has been abandonment and/or deintensification. The decoupling process has reduced the concentration of nitrates and suspended solids in a number of subbasins. Although agricultural production and water efficiency in the basin have improved, high erosion rates have not yet been addressed. 

  16. Maturation and growth curves of Macrobrachium Carcinus (Linnaeus (Crustacea, Decapoda, Palaemonidae from Ribeira de Iguape River, southern Brazil

    Directory of Open Access Journals (Sweden)

    Wagner C Valenti

    1994-01-01

    Full Text Available In this paper, female Macrobrachium carcinus (Linnaeus, 1758 maturation curve, weight/length relationship, length and weight growth curves were studied. Prawns were captured, by traps, in Ribeira de Iguape river (24ºS and 47ºW, southern Brazil. There were used 207 females. It was observed that M. carcinus presents several spawnings during its life cycle and reproductive period goes on, at least till six years old. Weight/length relationship can be represented for the equation W = 8.73 E-3 L3.28. Expressions obtained for length and weight growth curves are Lt = 21 .0 (1-e-0493t and Wt= 190 (1-e-0493t3.28. respectively. A symptotic maximum length and asymptotic maximum weight are nearly attained at six and eight years old, respectively.

  17. Meteorology of the Southern Global Plume: African and South American Fires Pollute the South Pacific

    Science.gov (United States)

    Guo, Z.; Chatfield, R. B.

    1999-01-01

    An immense global plume of CO meanders widely around the world in the Southern Hemisphere. It arises over Southern America and Africa and flows eastward. The first emissions are in tropical Brazil, and the plume circulates around the world to South America again. The plume was largely unexpected until there were aircraft studies made in NASA's Pacific Exploratory Mission - Tropics (Part A). This paper describes the meteorology of the Global Plume, as our simulation, with a synoptic model adapted to global transport, reveals it with a tracer-CO simulation. The observations and their simulation require a particular set of conditions of pollutant accumulation, cumulonimbus venting with required strengths at a narrow range of altitude. Additionally, a particular subtropical conduction region, over the Indian Ocean, Australia, and the westeRNmost South Pacific, relatively free of storms, appears to be a key part of the mechanism. These conclusions are the results of a synoptic reconstruction of the PEMT-A period, September- October, 1996.

  18. Game auction prices are not related to biodiversity contributions of southern African ungulates and large carnivores

    Science.gov (United States)

    Dalerum, Fredrik; Miranda, Maria

    2016-02-01

    There is an urgent need for human societies to become environmentally sustainable. Because public policy is largely driven by economic processes, quantifications of the relationship between market prices and environmental values can provide important information for developing strategies towards sustainability. Wildlife in southern Africa is often privately owned and traded at game auctions to be utilized for commercial purposes mostly related to tourism. This market offers an interesting opportunity to evaluate how market prices relate to biologically meaningful species characteristics. In this market, prices were not correlated with species contributions to either phylogenetic or functional diversity, and species contributions to phylogenetic or functional diversity did not influence the trends in prices over time for the past 20 years. Since this economic market did not seem to appreciate evolutionary or ecologically relevant characteristics, we question if the game tourism market may contribute towards biodiversity conservation in southern Africa. We suggest that market prices in general may have limited values as guides for directing conservation and environmental management. We further suggest that there is a need to evaluate what humans value in biological organisms, and how potentially necessary shifts in such values can be instigated.

  19. Ethno-botanical study of the African star apple (Chrysophyllum albidum G. Don in the Southern Benin (West Africa

    Directory of Open Access Journals (Sweden)

    Houessou Laurent G

    2012-10-01

    Full Text Available Abstract Background In addition to plant species biology and ecology, understanding the folk knowledge systems related to the use of plant species and how this knowledge system influences the conservation of plant species is an important issue in the implementation of sustainable strategies of biodiversity conservation programs. This study aimed at providing information on the use and local knowledge variation on Chrysophyllum albidum G. Don a multipurpose tree species widely used in southern Benin. Methods Data was collected through 210 structured interviews. Informants were randomly selected from ten villages. The fidelity level and use value of different plant parts of C. albidum were estimated. The variation in ethnobotanical knowledge was assessed by comparing the use value between ethnic, gender and age groups. In order to assess the use pattern of the different plant parts in folk medicine, a correspondence analysis was carried out on the frequency citation of plant parts. Results Four categories of use (food, medicine, firewood and timber were recorded for C. albidum. With respect to the different plant parts, the fleshy pulp of the African star apple fruit showed high consensus degree as food among the informants. Fifteen diseases were reported to be treated by the different parts of C. albidum in the region. Correspondence analysis revealed the specificity of each part in disease treatment. There was no significant difference among ethnic groups regarding the ethno-botanical use value of C. albidum. However, significant difference existed between genders and among age groups regarding the knowledge of the medical properties of this species. Conclusions C. albidum is well integrated in the traditional agroforestry system of the southern Benin. Despite its multipurpose character, this species remains underutilized in the region. Considering the current threat of habitat degradation, action is needed in order to ensure the long term

  20. The influence of El Niño-Southern Oscillation regimes on eastern African vegetation and its future implications under the RCP8.5 warming scenario

    Science.gov (United States)

    Fer, Istem; Tietjen, Britta; Jeltsch, Florian; Wolff, Christian

    2017-09-01

    The El Niño-Southern Oscillation (ENSO) is the main driver of the interannual variability in eastern African rainfall, with a significant impact on vegetation and agriculture and dire consequences for food and social security. In this study, we identify and quantify the ENSO contribution to the eastern African rainfall variability to forecast future eastern African vegetation response to rainfall variability related to a predicted intensified ENSO. To differentiate the vegetation variability due to ENSO, we removed the ENSO signal from the climate data using empirical orthogonal teleconnection (EOT) analysis. Then, we simulated the ecosystem carbon and water fluxes under the historical climate without components related to ENSO teleconnections. We found ENSO-driven patterns in vegetation response and confirmed that EOT analysis can successfully produce coupled tropical Pacific sea surface temperature-eastern African rainfall teleconnection from observed datasets. We further simulated eastern African vegetation response under future climate change as it is projected by climate models and under future climate change combined with a predicted increased ENSO intensity. Our EOT analysis highlights that climate simulations are still not good at capturing rainfall variability due to ENSO, and as we show here the future vegetation would be different from what is simulated under these climate model outputs lacking accurate ENSO contribution. We simulated considerable differences in eastern African vegetation growth under the influence of an intensified ENSO regime which will bring further environmental stress to a region with a reduced capacity to adapt effects of global climate change and food security.

  1. Focus on CSIR research in pollution waste: The South African river health programme

    CSIR Research Space (South Africa)

    Hill, Liesl

    2007-08-01

    Full Text Available the design of the River Health Programme (RHP) to monitor the health of rivers in South Africa. The RHP forms part of a bigger initiative, the National Aquatic Ecosystem Health Monitoring Programme which will eventually cover all surface water resources...

  2. Assessment of the macro-invertebrate fauna of rivers in southern ...

    African Journals Online (AJOL)

    This study evaluated the macro-invertebrate fauna in water bodies of southern Nigeria spanning the rainforest and derived savanna ecozones. The benthic macro-invertebrate fauna of Edo Ecozone comprises 55 taxa, belonging to 13 major groups. The abundance of major taxonomic groups varied considerably among the ...

  3. Do indigenous Southern African cattle breeds have the right genetics for commercial production of quality meat?

    Science.gov (United States)

    Strydom, P E

    2008-09-01

    The establishment of cattle breeds which are now indigenous to Africa is believed by historians to be very closely associated with man, his development, migration and specific behaviour from 6000 years BC. Today these breeds compete with exotic breeds in a commercial system driven by global economical principles. Results from various trials are discussed to verify if these breeds can adhere to these principles and compete in the South African beef market to produce quality beef economically. Variation in frame size among indigenous breeds will determine their suitability as feedlot cattle depending on the price and feed margins driving profit in this industry sector. Meat quality analyses indicate small or no differences between indigenous and exotic European/British breeds but with potentially superior quality compared to Bos indicus breeds.

  4. Changes in the rotifers of Ikpoba River Dam, Benin City, southern ...

    African Journals Online (AJOL)

    Plankton samples were taken fortnightly from the Ikpoba River Dam from February to June 1992 to determine changes in the rotifer community. Fifty-three species of rotifers belonging to thirteen families were identified. One species, Macrochaetus subquadratus of the family Trichotridae was recorded for the first time in ...

  5. Understanding the experiences of married Southern African women in protecting themselves from HIV/AIDS: a systematic review and meta-synthesis.

    Science.gov (United States)

    Timba-Emmanuel, Tabeth; Kroll, Thilo; Renfrew, Mary J; MacGillivray, Steve

    2017-07-27

    Whilst marriage has been repeatedly identified in the literature as an HIV risk factor amongst Southern African women, not much is known about women's perception of their role, experiences and strategies used to address HIV risks in the context of a marriage. The aim of the study was to synthesise perceptions, experiences and strategies of married Southern African women in the prevention of HIV. A systematic review of qualitative studies was conducted. Three electronic databases (Medline, Cinahl and PsycINFO) were systematically searched to identify relevant literature. The meta-synthesis process followed Sandelowski and Barroso's [2007. Handbook for Synthesizing Qualitative Research. Springer Publishing Company] recommendations. Of 7 609 papers, 15 were included in the review. The quality of the included studies was variable. In the final synthesis stage, three broad analytic themes emerged: contextual background, cues to preventive behaviour, and HIV prevention strategies. Findings were used to develop a conceptual framework for studying HIV/AIDS prevention experiences of married Southern African women.

  6. Controls on sinuosity in the sparsely vegetated Fossálar River, southern Iceland

    Science.gov (United States)

    Ielpi, Alessandro

    2017-06-01

    Vegetation exerts strong controls on fluvial sinuosity, providing bank stability and buffering surface runoff. These controls are manifest in densely vegetated landscapes, whereas sparsely vegetated fluvial systems have been so far overlooked. This study integrates remote sensing and gauging records of the meandering to wandering Fossálar River, a relatively steep-sloped ( 0.05), suggesting that relationships between the two are mediated by intervening variables and uncertain lag times. By comparison, discharge regime and fluvial planform show direct correlation over monthly to yearly time scales, with stable discharge stages accompanying the accretion of meander bends and peak floods related to destructive point-bar reworking. Rapid planform change is aided by the unconsolidated nature of unrooted alluvial banks, with recorded rates of lateral channel-belt migration averaging 18 m/yr. Valley confinement and channel mobility also control the geometry and evolution of individual point bars, with the highest degree of spatial geomorphic variability recorded in low-gradient stretches where lateral migration is unimpeded. Point bars in the Fossálar River display morphometric values comparable to those of other sparsely vegetated rivers, suggesting shared scalar properties. This conjecture prompts the need for more sophisticated integrations between remote sensing and gauging records on modern rivers lacking widespread plant life. While a large volume of experimental and field-based work maintains that thick vegetation has a critical role in limiting braiding, thus favouring sinuosity, this study demonstrates the stronger controls of discharge regime and alluvial morphology on sparsely vegetated sinuous rivers.

  7. Spatial distribution of organic contaminants in three rivers of Southern England bound to suspended particulate material and dissolved in water.

    Science.gov (United States)

    Wilkinson, John L; Hooda, Peter S; Swinden, Julian; Barker, James; Barton, Stephen

    2017-09-01

    The spatial distribution of pharmaceuticals, personal care products (PPCPs) and other emerging contaminants (ECs) such as plasticisers, perflourinated compounds (PFCs) and illicit drug metabolites in water and bound to suspended particulate material (SPM) is not well-understood. Here, we quantify levels of thirteen selected contaminants in water (n=88) and their partition to suspended particulate material (SPM, n=16) in three previously-unstudied rivers of Greater London and Southern England during a key reproduction/spawning period. Analysis was conducted using an in-house validated method for Solid Phase Extraction followed by High-Performance Liquid Chromatography-Tandem Mass-Spectrometry. Analytes were extracted from SPM using an optimised method for ultrasonic-assisted solvent extraction. Detection frequencies of contaminants dissolved in water ranged from 3% (ethinylestradiol) to 100% (bisphenol-A). Overall mean concentrations in the aqueous-phase ranged from 14.7ng/L (benzoylecgonine) to 159ng/L (bisphenol-A). Sewage treatment works (STW) effluent was the predominant source of pharmaceuticals, while plasticisers/perfluorinated compounds may additionally enter rivers via other sources. In SPM, detection frequencies ranged from 44% (PFOA) to 94% (hydroxyacetophenone). Mean quantifiable levels of analytes bound to SPM ranged from 13.5ng/g dry SPM (0.33ng bound/L water) perfluorononanoic acid to 2830ng/g dry SPM (14.3ng bound/L water) perfluorooctanesulfonic acid. Long chain (>C7) amphipathic and acidic PFCs were found to more preferentially bind to SPM than short chain PFCs and other contaminants (Kd=34.1-75.5 vs work (n=104) enabled ANOVA followed by Tukey HSD post-hoc tests to establish significant trends in PPCP/EC spatial distribution from headwaters through downstream stretches of studied rivers. Novel findings include environmental Kd calculations, the occurrence of contaminants in river headwaters, increases in contaminant metabolite concentrations

  8. New taxa, new records and name changes for southern African plants

    Directory of Open Access Journals (Sweden)

    G. E. Gibbs Russell

    1987-12-01

    Full Text Available Alterations for the year 1986 to the inventory maintained in PRECIS are reported for bryophytes, pteridophytes and monocotyledons, and for a few dicotyledons. For the cryptogams and monocots there are 77 newly described species or infraspecific taxa, 27 names brought back into use, and nine species newly reported for southern Africa, resulting in 113 additions to the total list of species. Five species were removed because they were mistakenly recorded from the area. Seventy-five names have gone into synonymy, there are 52 new combinations, and there are 35 orthographic corrections, resulting in 237 alterations to the list of species. The total of 355 additions, deletions and alterations represents about 5% of the total species and infraspecific taxa for the cryptogams and monocots.

  9. Democratic local governance in the Southern African Development Community region: Some emerging issues and challenges

    Directory of Open Access Journals (Sweden)

    Bornwell Chikulo

    2010-03-01

    Full Text Available Recent reforms have been transforming the structure of local governance in the Southern Africa Development Community (SADC region. Since the 1990s, a critical objective of governance reform has been the strengthening of local government by the decentralization of powers, resources and responsibilities to local authorities and other locally administered bodies. These reforms have been labelled ‘democratic decentralization’ by scholars (Ribot, 2004; Olowu & Wunsch, 2004. Democratic decentralization refers to initiatives which entail the transfer of significant authority, responsibility for services, fiscal and human resources to local governance. The objective of the reforms was to capacitate local governance structures, as well as to increase the capacity and productivity of the public sector in general (Hope & Chikulo, 2000. Efforts to improve institutional effectiveness, accountability and service delivery at the local level thus have been a major focus throughout the region.

  10. Rainfall variability and its association with El Niño Southern Oscillation in Tons River Basin, India

    Science.gov (United States)

    Duhan, Darshana; Pandey, Ashish; Srivastava, Puneet

    2017-04-01

    In this study, rainfall variability in connection with El Niño Southern Oscillation (ENSO) over the Tons River Basin which is a sub-basin of the Ganges River has been examined. The rainfall trends on annual and seasonal basis for 15 weather stations were examined using the data of 1951-2004. Furthermore, the association between ENSO and rainfall was analyzed using three methods, namely cumulative frequency distributions, correlation analysis, and composite analysis. The annual rainfall series analysis indicated a significant decrease at Govindgarh (5.5 mm/year) and Meja (6.6 mm/year) stations. Seasonal rainfall analysis indicated significant decreasing trends at fourteen stations in pre-monsoon season, ten stations in winter season, two stations in post-monsoon, and only one station in monsoon season. The average frequency of occurrence of drought is once in every 4-7 years. Only monsoon season rainfall showed a significant negative correlation with Niño 3.4 SST at almost all the stations. During El Niño, the probability of below normal rainfall is high. However, during La Niña, the probability of above normal or near normal rainfall is high in monsoon season. Furthermore, comparison of results before (Pre76) and after (Post76) the climate shift revealed that the relationship between rainfall and El Niño has strengthened after the climate shift.

  11. Regional and temporal variation in minor ions in groundwater of a part of a large river delta, southern India.

    Science.gov (United States)

    Elumalai, Vetrimurugan; Brindha, K; Elango, L

    2017-07-01

    Impact of agricultural activities on groundwater can be determined from the concentration of nutrients present in groundwater. This study was carried out with the aim to assess the minor ions content of groundwater and to identify its sources, spatial, and seasonal variations in a part of the Cauvery River basin, southern India. Groundwater samples were collected from July 2007 to September 2009 and were analyzed for minor ions. These ions were in the order of dominance of nitrate> phosphate> bromide> fluoride> ammonium= nitrite> lithium. The concentration of ions tends to increase towards the coast except for fluoride. Increased concentration of ions identified in shallow wells than in deep wells with an exception of few locations indicates the impact of human activities. Relatively high concentration of agriculture-sourced nitrate was identified which pose a threat to groundwater suitability for agriculture and domestic usage. Combined influence of use of agrochemicals, improper sewage disposal, aquaculture activities, seawater intrusion due to heavy pumping near the coast, and natural weathering of aquifer materials are the major sources. Also, fine grain sediments of this area aid in poor flushing of the ions towards the sea resulting in accumulation of higher concentration of ions. A sustainable management strategy is essential to control the concentration of these ions, especially nitrate. Reduced use of fertilizers, increasing the rainfall recharge for diluting the pollutants in groundwater and maintaining the river flow for sufficiently longer period to reduce dependence on groundwater for irrigation can help to improve the situation.

  12. Species richness and abundance of bats in fragments of the stational semidecidual forest, Upper Paraná River, southern Brazil

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    H. Ortêncio-Filho

    Full Text Available The Upper Paraná River floodplain is inserted in a region of the Mata Atlântica biome, which is a critical area to preserve. Due to the scarcity of researches about the chiropterofauna in this region, the present study investigated species richness and abundance of bats in remnants from the stational semidecidual forest of the Upper Paraná River, southern Brazil. Samplings were taken every month, from January to December 2006, using 32 mist nets with 8.0 x 2.5 m, resulting in 640 m²/h and totaling a capture effort of 87,040 m²/h. In order to estimate the species richness, the following estimators were employed Chao1 and Jack2. During the study, a total of 563 individuals belonging to 17 species (Artibeus planirostris, Artibeus lituratus, Carollia perspicillata, Platyrrhinus lineatus, Sturnira lilium, Artibeus fimbriatus, Myotis nigricans, Desmodus rotundus, Artibeus obscurus, Noctilio albiventris, Phylostomus discolor, Phylostomus hastatus, Chrotopterus auritus, Lasiurus ega, Chiroderma villosum, Pygoderma bilabiatum and Lasiurus blossevillii were captured. The estimated richness curves tended to stabilize, indicating that most of the species were sampled. Captured species represented 10% of the taxa recorded in Brazil and 28% in Paraná State, revealing the importance of this area for the diversity of bats. These findings indicate the need to determine actions aiming to restrict human activities in these forest fragments, in order to minimize anthropogenic impacts on the chiropterofauna.

  13. Modelling the impact of a subsurface barrier on groundwater flow in the lower Palar River basin, southern India

    Science.gov (United States)

    Senthilkumar, M.; Elango, L.

    2011-06-01

    Groundwater modelling is widely used as a management tool to understand the behaviour of aquifer systems under different hydrological stresses, whether induced naturally or by humans. The objective of this study was to assess the effect of a subsurface barrier on groundwater flow in the Palar River basin, Tamil Nadu, southern India. Groundwater is supplied to a nearby nuclear power plant and groundwater also supplies irrigation, industrial and domestic needs. In order to meet the increasing demand for groundwater for the nuclear power station, a subsurface barrier/dam was proposed across Palar River to increase the groundwater heads and to minimise the subsurface discharge of groundwater into the sea. The groundwater model used in this study predicted that groundwater levels would increase by about 0.1-0.3 m extending out a distance of about 1.5-2 km from the upstream side of the barrier, while on the downstream side, the groundwater head would lower by about 0.1-0.2 m. The model also predicted that with the subsurface barrier in place the additional groundwater requirement of approximately 13,600 m3/day (3 million gallons (UK)/day) can be met with minimum decline in regional groundwater head.

  14. Comparison of Statistical Downscaling Methods for Monthly Total Precipitation: Case Study for the Paute River Basin in Southern Ecuador

    Directory of Open Access Journals (Sweden)

    L. Campozano

    2016-01-01

    Full Text Available Downscaling improves considerably the results of General Circulation Models (GCMs. However, little information is available on the performance of downscaling methods in the Andean mountain region. The paper presents the downscaling of monthly precipitation estimates of the NCEP/NCAR reanalysis 1 applying the statistical downscaling model (SDSM, artificial neural networks (ANNs, and the least squares support vector machines (LS-SVM approach. Downscaled monthly precipitation estimates after bias and variance correction were compared to the median and variance of the 30-year observations of 5 climate stations in the Paute River basin in southern Ecuador, one of Ecuador’s main river basins. A preliminary comparison revealed that both artificial intelligence methods, ANN and LS-SVM, performed equally. Results disclosed that ANN and LS-SVM methods depict, in general, better skills in comparison to SDSM. However, in some months, SDSM estimates matched the median and variance of the observed monthly precipitation depths better. Since synoptic variables do not always present local conditions, particularly in the period going from September to December, it is recommended for future studies to refine estimates of downscaling, for example, by combining dynamic and statistical methods, or to select sets of synoptic predictors for specific months or seasons.

  15. Decline of General Intelligence in Children Exposed to Manganese from Mining Contamination in Puyango River Basin, Southern Ecuador.

    Science.gov (United States)

    Betancourt, Óscar; Tapia, Marlene; Méndez, Ignacio

    2015-09-01

    Based on ecosystem approaches to health (Ecohealth), this study sought to identify neurobehavioral disorders in children exposed to several levels of toxic metal pollution from gold mining in the Puyango River Basin, Southern Ecuador. Ninety-three children born or living in the study area participated in the study. A neurobehavioral test battery consisting of 12 tests assessing various functions of the nervous system was applied as well as a questionnaire regarding events of exposure of children's mothers to contaminants during perinatal period. Hair samples were taken from children to determine manganese concentrations. Descriptive and inferential statistics were applied in order to examine possible relationships between exposure events, hair manganese, and neurobehavioral disorders. Having controlled co-variables such as age and educational level, it was found that children with elevated levels of hair manganese (over 2 μg/g) had poor performance in the test of general intelligence (Raven's Progressive Color Matrices Scale PCM). The Ecohealth approach helped to identify that children in the lower Puyango Basin with very elevated levels of manganese in the river water (970 µg/L) are the ones who have the highest levels of hair manganese and the worst performance in the intelligence test.

  16. Uniting Christian Students� Association�s pilgrimage to overcome colonial racism: A southern African postcolonial missiological dialogue

    Directory of Open Access Journals (Sweden)

    R.W. (Reggie Nel

    2015-03-01

    Full Text Available World Christianity has been enriched by Christian student movements such as the Uniting Christian Students� Association (UCSA from South Africa. This article, based on my recent doctoral research, starts with the affirmation of the ambiguous relations of these movements with colonial racism. However, faced with new challenges in a postcolonial context, there are key impulses to be gained by an inter-subjective, but also interdisciplinary dialogue with these movements as they negotiate their calling. By focussing on one movement within the southern African context, UCSA, in particular its formation and development since the demise of apartheid in South Africa, the article aims to present an attempt to understand the missionary praxis of UCSA through a postcolonial missiological matrix. The article draws on the theological disciplines of missiology, systematic theology, church history, contextual theology, as well as the methodologies in non-theologic disciplines like sociology, in particular social movement studies, and history. The findings show, amongst others, a growing complexity in relation to its agency, how it frames its world and also how it used its authoritative sources to discern its calling. The article closes with some key insights and pointers relevant for faith communities in their mission to overcome colonial racism.Intradisciplinary and/or interdisciplinary implications: The teaching and research in missiology and systematic theology in how the challenge of colonial racism is addressed, methodologically.

  17. The self-organizing map, a new approach to apprehend the Madden-Julian Oscillation influence on the intraseasonal variability of rainfall in the southern African region

    Science.gov (United States)

    Oettli, Pascal; Tozuka, Tomoki; Izumo, Takeshi; Engelbrecht, Francois A.; Yamagata, Toshio

    2014-09-01

    The Madden-Julian Oscillation (MJO) is the major mode of intraseasonal variability (30-60 days) in the tropics, having large rainfall impacts globally, and possibly on southern Africa. However, the latter impact is not well understood and needs to be further explored. The life cycle of the MJO, known to be asymmetric, has been nevertheless analyzed usually through methods constrained by both linearity and orthogonality, such as empirical orthogonal function analysis. Here we explore a non-linear classification method, the self-organizing map (SOM), a type of artificial neural network used to produce a low-dimensional representation of high-dimensional datasets, to capture more accurately the life cycle of the MJO and its global impacts. The classification is applied on intraseasonal anomalies of outgoing longwave radiation within the tropical region over the 1980-2009 period. Using the SOM to describe the MJO is a new approach, complimentary to the usual real-time multivariate MJO index. It efficiently captures this propagative phenomenon and its seasonality, and is shown to provide additional temporal and spatial information on MJO activity. For each node, the subtropical convection is analyzed, with a particular focus on the southern Africa region. Results show that the convection activity over the central tropical Indian Ocean is a key factor influencing the intraseasonal convective activity over the southern African region. Enhanced (suppressed) convection over the central Indian Ocean tends to suppress (enhance) convection over the southern African region with a 10-day lag by modulating the moisture transport.

  18. Do microplastic loads reflect the population demographics along the southern African coastline?

    Science.gov (United States)

    Nel, Holly Astrid; Hean, Jeffrey William; Noundou, Xavier Siwe; Froneman, Pierre William

    2017-02-15

    Plastic pollution is a major anthropogenic contaminant effecting the marine environment and is often associated with high human population densities and industrial activities. The microplastic (63 to 5000μm) burden of beach sediment and surf-zone water was investigated at selected sites along the entire length of the South African coastline. It was predicted that samples collected in areas of high population density, would contain a higher microplastic burden than those along coasts that demonstrate very low population densities. With the exception of water column microplastics within Richard's Bay Harbour (413.3±77.53particles·m(-3)) and Durban Harbour (1200±133.2particles·m(-3)), there were no significant spatial differences in microplastic loads. This supports the theory that harbours act as a source of microplastics for the surrounding marine environment. Additionally, the absence of any spatial variation highlights the possible long range distribution of microplastic pollutants by large scale ocean currents. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Do national drug policies influence antiretroviral drug prices? Evidence from the Southern African Development community.

    Science.gov (United States)

    Liu, Yao; Galárraga, Omar

    2017-03-01

    The efficacy of low- and middle-income countries’ (LMIC) national drug policies in managing antiretroviral (ARV) pharmaceutical prices is not well understood. Though ARV drug prices have been declining in LMIC over the past decade, little research has been done on the role of their national drug policies. This study aims to (i) analyse global ARV prices from 2004 to 2013 and (ii) examine the relationship of national drug policies to ARV prices. Analysis of ARV drug prices utilized data from the Global Price Reporting Mechanism from the World Health Organization (WHO). Ten of the most common ARV drugs (first-line and second-line) were selected. National drug policies were also assessed for 12 countries in the South African Development Community (SADC), which self-reported their policies through WHO surveys. The best predictor of ARV drug price was generic status—the generic versions of 8 out of 10 ARV drugs were priced lower than branded versions. However, other factors such as transaction volume, HIV prevalence, national drug policies and PEPFAR/CHAI involvement were either not associated with ARV drug price or were not consistent predictors of price across different ARV drugs. In the context of emerging international trade agreements, which aim to strengthen patent protections internationally and potentially delay the sale of generic drugs in LMIC, this study shines a spotlight on the importance of generic drugs in controlling ARV prices. Further research is needed to understand the impact of national drug policies on ARV prices.

  20. Diet of Iheringichthys labrosus (Siluriformes, Pimelodidae in the Ibicuí River, Southern Brazil

    Directory of Open Access Journals (Sweden)

    Camila K. Fagundes

    2008-03-01

    Full Text Available The diet of the benthic-feeding fish Iheringichthys labrosus (Lütken, 1874 was analyzed. Samples were taken bimonthly from December 1999 to January 2002, in three sites of the Ibicuí River, a tributary of Uruguay River basin (Rio Grande do Sul, Brazil. In each sampling point the specimens were collected in lentic and lotic environments. Gillnets and trammel nets were examined every 6 hours (6h, 12h, 18h and 24h. Diet description was based on the frequency of occurrence and the volume of each food item to obtain the Alimentary Index (IAi. The average stomach fullness was adopted to detect variations in the feeding activity according to the season, the circadian rhythm and the environment. Chironomids were the most important food item, followed by mollusks, and feeding activity was highest in summer, during daylight (6h and 12h, and in the lotic environment of the second sampling point.

  1. Transgressing the norm: Transformative agency in community-based learning for sustainability in southern African contexts

    Science.gov (United States)

    Lotz-Sisitka, Heila; Mukute, Mutizwa; Chikunda, Charles; Baloi, Aristides; Pesanayi, Tichaona

    2017-11-01

    Environment and sustainability education processes are often oriented to change and transformation, and frequently involve the emergence of new forms of human activity. However, not much is known about how such change emerges from the learning process, or how it contributes to the development of transformative agency in community contexts. The authors of this article present four cross-case perspectives of expansive learning and transformative agency development in community-based education in southern Africa, studying communities pursuing new activities that are more socially just and sustainable. The four cases of community learning and transformative agency focus on the following activities: (1) sustainable agriculture in Lesotho; (2) seed saving and rainwater harvesting in Zimbabwe; (3) community-based irrigation scheme management in Mozambique; and (4) biodiversity conservation co-management in South Africa. The case studies all draw on cultural-historical activity theory to guide learning and change processes, especially third-generation cultural-historical activity theory (CHAT), which emphasises expansive learning in collectives across interacting activity systems. CHAT researchers, such as the authors of this article, argue that expansive learning can lead to the emergence of transformative agency. The authors extend their transformative agency analysis to probe if and how expansive learning might also facilitate instances of transgressing norms - viewed here as embedded practices which need to be reframed and changed in order for sustainability to emerge.

  2. A review of taurodontism with new data on indigenous southern African populations.

    Science.gov (United States)

    Constant, D A; Grine, F E

    2001-11-01

    The prevalence and degree of taurodontism (enlargement of the pulp cavity) in the mandibular permanent molars of two recent population samples from southern Africa were investigated quantitatively from lateral radiographs. The degree of occlusal wear was scored and two measures of relative pulp cavity size were recorded for each tooth. There was a significant association between increased attrition and a reduction in the size of the pulp cavity when all of the teeth were considered together, but no correlation among individual molar types within each sample. In both the Zulu (n=68 individuals) and Khoisan (n=28 individuals) samples, third molars had the highest prevalence of taurodontism and first molars the lowest. The data for Zulus are similar to those recorded for other modern populations (e.g. white and black Americans, and Israelis), whereas the Khoisan data exhibit significantly higher frequencies. An increased appreciation of the distribution of this variant in modern human populations would contribute to an understanding of its possible evolutionary significance in the human fossil record.

  3. Transgressing the norm: Transformative agency in community-based learning for sustainability in southern African contexts

    Science.gov (United States)

    Lotz-Sisitka, Heila; Mukute, Mutizwa; Chikunda, Charles; Baloi, Aristides; Pesanayi, Tichaona

    2017-12-01

    Environment and sustainability education processes are often oriented to change and transformation, and frequently involve the emergence of new forms of human activity. However, not much is known about how such change emerges from the learning process, or how it contributes to the development of transformative agency in community contexts. The authors of this article present four cross-case perspectives of expansive learning and transformative agency development in community-based education in southern Africa, studying communities pursuing new activities that are more socially just and sustainable. The four cases of community learning and transformative agency focus on the following activities: (1) sustainable agriculture in Lesotho; (2) seed saving and rainwater harvesting in Zimbabwe; (3) community-based irrigation scheme management in Mozambique; and (4) biodiversity conservation co-management in South Africa. The case studies all draw on cultural-historical activity theory to guide learning and change processes, especially third-generation cultural-historical activity theory (CHAT), which emphasises expansive learning in collectives across interacting activity systems. CHAT researchers, such as the authors of this article, argue that expansive learning can lead to the emergence of transformative agency. The authors extend their transformative agency analysis to probe if and how expansive learning might also facilitate instances of transgressing norms - viewed here as embedded practices which need to be reframed and changed in order for sustainability to emerge.

  4. Eremiolirion, a new genus of southern African Tecophilaeaceae, and taxonomic notes on Cyanella alba

    Directory of Open Access Journals (Sweden)

    J. C. Manning

    2005-12-01

    Full Text Available The generic affiliation of Cyanella amboensis Schinz has been uncertain since the species was excluded from the genus Cyanella L. in 1991. The species has two leaves, a divaricately branching inflorescence, ebracteolate pedicels, and acti- nomorphic flowers with monomorphic anthers. It is endemic to the western parts of central and northern Namibia. Other species of Cyanella have several leaves, racemose inflorescences, bracteolate pedicels, zygomorphic flowers with dimor­phic anthers, and are endemic or near-endemic to the winter rainfall region in southwestern South Africa and southern Namibia. These differences are consistent with the recognition of the species as a distinct genus within the family. Phylogenetic analysis of plastid DNA sequences indicates that C.  amboensis Schinz is sister to the other species of Cyanella, a relationship that also supports its independent generic status. The monotvpic genus Eremiolirion is according­ly erected to accommodate the species. Minor differences in flower colour and vegetative morphology in Cyanella alba L.f. are shown to correlate with the three disjunct groups of populations in which the species occurs, and these populations are recognized at the level of subspecies.

  5. Diet of Astyanax species (Teleostei, Characidae in an Atlantic Forest River in Southern Brazil

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    Fábio Silveira Vilella

    2002-06-01

    Full Text Available Feeding habits of six species of Astyanax from river Maquiné are described. Fishes were sampled bi-monthly from November/95 to September/96 in two zones of the river. Items were identified, counted and had their abundance estimated according to a semi-quantitative scale. Frequency of occurrence, alimentary importance index (IFI values and a similarity analysis of diets for each species-river zone sample were examined. All the species were considered typically omnivorous, with insects and vegetal matter being the most important items in their diet. These species could act as seed dispersers, particularly for macrophytes. Intra-specific spatial differences were not observed in comparisons of samples from two diferent regions of the river, except for A. fasciatus. The presence of Podostemaceae macrophytes in the mid-course of the river seemed to be important both as an autochthonous food resource and as habitat for several organisms preyed by the Astyanax species.Seis espécies do gênero Astyanax, presentes no rio Maquiné, RS, foram estudadas quanto aos seus hábitos alimentares. Os exemplares foram amostrados bimensalmente de novembro de 1995 a setembro de 1996 nas zonas ritral e potamal do rio. Os itens alimentares foram identificados e quantificados de acordo com uma escala semi-quantitativa de abundância, utilizando-se para análise a frequência de ocorrência e um índice de importância alimentar para cada espécie e zona do rio. Análises multivariadas de agrupamento e ordenação foram utilizadas para comparar as dietas intra e interespecíficas. Todas as espécies foram consideradas onivoras, sendo que os itens mais importantes foram os insetos e restos de vegetais superiores. Sugere-se que as espécies estudadas possam atuar como dispersoras de sementes, particularmente para macrófitas. Diferenças espaciais intraespecíficas não foram encontradas, exceto para A. fasciatus. A presença de Podostemaceae no curso médio do rio parece

  6. Trophic interactions of the endangered Southern river otter ( Lontra provocax) in a Chilean Ramsar wetland inferred from prey sampling, fecal analysis, and stable isotopes

    Science.gov (United States)

    Franco, Marcela; Guevara, Giovany; Correa, Loreto; Soto-Gamboa, Mauricio

    2013-04-01

    Non-invasive methodological approaches are highly recommended and commonly used to study the feeding ecology of elusive and threatened mammals. In this study, we use multiple lines of evidence to assess the feeding strategies of the endangered Southern river otter, by determining seasonal prey availability (electrofishing), analysis of undigested prey remains (spraints), and the use of stable isotopes (δ15N and δ13C) in otter spraints ( n = 262) and prey in a wetland ecosystem of southern Chile (39°49'S, 73°15'W). Fecal and isotopic analyses suggest that the otter diet is restricted to a few prey items, particularly the less-mobile, bottom-living, and larger prey such as crayfish ( Samastacus spinifrons, 86.11 %) and crabs ( Aegla spp., 32.45 %), supplemented opportunistically by cyprinids ( Cyprinus carpio, 9.55 %) and catfish ( Diplomystes camposensis, 5.66 %). The results suggest that the river otter is highly specialized in bottom foraging. Isotopic signatures of food sources and feces revealed a mid-upper trophic position for the Southern river otter, with either higher or lower δ15N values than their potential prey items. δ13C values for river otters were less enriched than their potential food resources. We suggest that due to their narrow trophic niche and possible dependence on only a few food items, this species may be highly vulnerable to the reduction in its prey populations. Finally, maintaining the ecological interactions between Southern river otters and their prey is considered a central priority for the survival of this endangered carnivore mammal.

  7. Trophic interactions of the endangered Southern river otter (Lontra provocax) in a Chilean Ramsar wetland inferred from prey sampling, fecal analysis, and stable isotopes.

    Science.gov (United States)

    Franco, Marcela; Guevara, Giovany; Correa, Loreto; Soto-Gamboa, Mauricio

    2013-04-01

    Non-invasive methodological approaches are highly recommended and commonly used to study the feeding ecology of elusive and threatened mammals. In this study, we use multiple lines of evidence to assess the feeding strategies of the endangered Southern river otter, by determining seasonal prey availability (electrofishing), analysis of undigested prey remains (spraints), and the use of stable isotopes (δ(15)N and δ(13)C) in otter spraints (n = 262) and prey in a wetland ecosystem of southern Chile (39°49'S, 73°15'W). Fecal and isotopic analyses suggest that the otter diet is restricted to a few prey items, particularly the less-mobile, bottom-living, and larger prey such as crayfish (Samastacus spinifrons, 86.11%) and crabs (Aegla spp., 32.45%), supplemented opportunistically by cyprinids (Cyprinus carpio, 9.55%) and catfish (Diplomystes camposensis, 5.66%). The results suggest that the river otter is highly specialized in bottom foraging. Isotopic signatures of food sources and feces revealed a mid-upper trophic position for the Southern river otter, with either higher or lower δ(15)N values than their potential prey items. δ(13)C values for river otters were less enriched than their potential food resources. We suggest that due to their narrow trophic niche and possible dependence on only a few food items, this species may be highly vulnerable to the reduction in its prey populations. Finally, maintaining the ecological interactions between Southern river otters and their prey is considered a central priority for the survival of this endangered carnivore mammal.

  8. The influence of Pleistocene climatic changes and ocean currents on the phylogeography of the southern African barnacle, Tetraclita serrata (Thoracica; Cirripedia.

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    Terry V Reynolds

    Full Text Available The evolutionary effects of glacial periods are poorly understood for Southern Hemisphere marine intertidal species, particularly obligatory sessile organisms. We examined this by assessing the phylogeographic patterns of the southern African volcano barnacle, Tetraclita serrata, a dominant species on rocky intertidal shores. Restricted gene flow in some geographical areas was hypothesized based on oceanic circulation patterns and known biogeographic regions. Barnacle population genetic structure was investigated using the mitochondrial cytochrome oxidase subunit 1 (COI region for 410 individuals sampled from 20 localities spanning the South African coast. The mtDNA data were augmented by generating nuclear internal transcribed spacer 1 (ITS1 sequences from a subset of samples. Phylogenetic and population genetic analyses of mitochondrial DNA data reveal two distinct clades with mostly sympatric distributions, whereas nuclear analyses reveal only a single lineage. Shallow, but significant structure (0.0041-0.0065, P<0.01 was detected for the mtDNA data set, with the south-west African region identified as harbouring the highest levels of genetic diversity. Gene flow analyses on the mtDNA data show that individuals sampled in south-western localities experience gene flow primarily in the direction of the Benguela Current, while south and eastern localities experience bi-directional gene flow, suggesting an influence of both the inshore currents and the offshore Agulhas Current in the larval distribution of T. serrata. The mtDNA haplotype network, Bayesian Skyline Plots, mismatch distributions and time since expansion indicate that T. serrata population numbers were not severely affected by the Last Glacial Maximum (LGM, unlike other southern African marine species. The processes resulting in the two morphologically cryptic mtDNA lineages may be the result of a recent historical allopatric event followed by secondary contact or could reflect

  9. The influence of Pleistocene climatic changes and ocean currents on the phylogeography of the southern African barnacle, Tetraclita serrata (Thoracica; Cirripedia).

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    Reynolds, Terry V; Matthee, Conrad A; von der Heyden, Sophie

    2014-01-01

    The evolutionary effects of glacial periods are poorly understood for Southern Hemisphere marine intertidal species, particularly obligatory sessile organisms. We examined this by assessing the phylogeographic patterns of the southern African volcano barnacle, Tetraclita serrata, a dominant species on rocky intertidal shores. Restricted gene flow in some geographical areas was hypothesized based on oceanic circulation patterns and known biogeographic regions. Barnacle population genetic structure was investigated using the mitochondrial cytochrome oxidase subunit 1 (COI) region for 410 individuals sampled from 20 localities spanning the South African coast. The mtDNA data were augmented by generating nuclear internal transcribed spacer 1 (ITS1) sequences from a subset of samples. Phylogenetic and population genetic analyses of mitochondrial DNA data reveal two distinct clades with mostly sympatric distributions, whereas nuclear analyses reveal only a single lineage. Shallow, but significant structure (0.0041-0.0065, P<0.01) was detected for the mtDNA data set, with the south-west African region identified as harbouring the highest levels of genetic diversity. Gene flow analyses on the mtDNA data show that individuals sampled in south-western localities experience gene flow primarily in the direction of the Benguela Current, while south and eastern localities experience bi-directional gene flow, suggesting an influence of both the inshore currents and the offshore Agulhas Current in the larval distribution of T. serrata. The mtDNA haplotype network, Bayesian Skyline Plots, mismatch distributions and time since expansion indicate that T. serrata population numbers were not severely affected by the Last Glacial Maximum (LGM), unlike other southern African marine species. The processes resulting in the two morphologically cryptic mtDNA lineages may be the result of a recent historical allopatric event followed by secondary contact or could reflect selective pressures

  10. Equity in HIV testing: evidence from a cross-sectional study in ten Southern African countries

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    Mitchell Steven

    2010-09-01

    Full Text Available Abstract Background HIV testing with counseling is an integral component of most national HIV and AIDS prevention strategies in southern Africa. Equity in testing implies that people at higher risk for HIV such as women; those who do not use condoms consistently; those with multiple partners; those who have suffered gender based violence; and those who are unable to implement prevention choices (the choice-disabled are tested and can have access to treatment. Methods We conducted a household survey of 24,069 people in nationally stratified random samples of communities in Botswana, Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Tanzania, Zambia, and Zimbabwe. We asked about testing for HIV in the last 12 months, intention to test, and about HIV risk behaviour, socioeconomic indicators, access to information, and attitudes related to stigma. Results Across the ten countries, seven out of every ten people said they planned to have an HIV test but the actual proportion tested in the last 12 months varied from 24% in Mozambique to 64% in Botswana. Generally, people at higher risk of HIV were not more likely to have been tested in the last year than those at lower risk, although women were more likely than men to have been tested in six of the ten countries. In Swaziland, those who experienced partner violence were more likely to test, but in Botswana those who were choice-disabled for condom use were less likely to be tested. The two most consistent factors associated with HIV testing across the countries were having heard about HIV/AIDS from a clinic or health centre, and having talked to someone about HIV and AIDS. Conclusions HIV testing programmes need to encourage people at higher risk of HIV to get tested, particularly those who do not interact regularly with the health system. Service providers need to recognise that some people are not able to implement HIV preventive actions and may not feel empowered to get themselves

  11. HIV-related discrimination among grade six students in nine Southern African countries.

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    Maughan-Brown, Brendan; Spaull, Nicholas

    2014-01-01

    HIV-related stigmatisation and discrimination by young children towards their peers have important consequences at the individual level and for our response to the epidemic, yet research on this area is limited. We used nationally representative data to examine discrimination of HIV-positive children by grade six students (n = 39,664) across nine countries in Southern Africa: Botswana, Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Zambia and Zimbabwe. Descriptive statistics are used to compare discrimination by country, gender, geographic location and socioeconomic status. Multivariate logistic regression is employed to assess potential determinants of discrimination. The levels and determinants of discrimination varied significantly between the nine countries. While one in ten students in Botswana, Malawi, South Africa and Swaziland would "avoid or shun" an HIV positive friend, the proportions in Lesotho, Mozambique, Zambia and Zimbabwe were twice as high (approximately 20%). A large proportion of students believed that HIV positive children should not be allowed to continue to attend school, particularly in Zambia (33%), Lesotho (37%) and Zimbabwe (42%). The corresponding figures for Malawi and Swaziland were significantly lower at 13% and 12% respectively. Small differences were found by gender. Children from rural areas and poorer schools were much more likely to discriminate than those from urban areas and wealthier schools. Importantly, we identified factors consistently associated with discrimination across the region: students with greater exposure to HIV information, better general HIV knowledge and fewer misconceptions about transmission of HIV via casual contact were less likely to report discrimination. Our study points toward the need for early interventions (grade six or before) to reduce stigma and discrimination among children, especially in schools situated in rural areas and poorer communities. In particular, interventions

  12. Tree cover and biomass increase in a southern African savanna despite growing elephant population.

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    Kalwij, J M; De Boer, W F; Mucina, L; Prins, H H T; Skarpe, C; Winterbach, C

    2010-01-01

    The growing elephant populations in many parts of southern Africa raise concerns of a detrimental loss of trees, resulting in overall reduction of biodiversity and ecosystem functioning. Elephant distribution and density can be steered through artificial waterpoints (AWPs). However, this leaves resident vegetation no relief during dry seasons. We studied how the introduction of eight AWPs in 1996 affected the spatiotemporal tree-structure dynamics in central Chobe National Park, an unfenced savanna area in northern Botswana with a dry-season elephant density of approximately 3.34 individuals per square kilometer. We hypothesized that the impact of these AWPs amplified over time and expanded in space, resulting in a decrease in average tree density, tree height, and canopy volume. We measured height and canopy dimensions of all woody plants around eight artificial and two seasonal waterpoints for 172 plots in 1997, 2000, and 2008. Plots, consisting of 50 x 2 m transects for small trees (0.20-3.00 m tall) nested within 50 x 20 m transects for large trees (> or = 3.0 m tall), were located at 100, 500, 1000, 2000, and 5000 m distance classes. A repeated-measures mixed-effect model showed that tree density, cover, and volume had increased over time throughout the area, caused by a combination of an increase of trees in lower size classes and a decrease in larger size classes. Our results indicate that the decrease of large trees can be attributed to a growing elephant population. Decrease or loss of particular tree size classes may have been caused by a loss of browser-preferred species while facilitating the competitiveness of less-preferred species. In spite of 12 years of artificial water supply and an annual elephant population growth of 6%, we found no evidence that the eight AWPs had a negative effect on tree biomass or tree structure. The decreasing large-tree component could be a remainder of a depleted but currently restoring elephant population.

  13. Systematics of the hypervariable Moraea tripetala complex (Iridaceae: Iridoideae of the southern African winter rainfall zone

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    P. Goldblatt

    2012-12-01

    Full Text Available Field and laboratory research has shown that the Moraea tripetala complex of western South Africa, traditionally treated as a single species, sometimes with two additional varieties, has a pattern of morphological and cytological variation too complex to be accommodated in a single species. Variation in floral structure, especially the shape of the inner tepals, degree of union of the filaments, anther length and pollen colour form coherent patterns closely correlated with morphology of the corm tunics, mode of vegetative reproduction, and in some instances capsule and seed shape and size. The morphological patterns also correlate with geography, flowering time and sometimes habitat. It is especially significant that different variants of the complex may co-occur, each with overlapping or separate flowering times, a situation that conflicts with a single species taxonomy. We propose recognizing nine species and three additional subspecies for plants currently assigned to M. tripetala. M. grandis, from the western Karoo, has virtually free filaments and leaves often ± plane distally; closely allied M. amabilis, also with ± free filaments and often hairy leaves, is centred in the western Karoo and Olifants River Valley. Its range overlaps that of M. cuspidata, which has narrowly channelled, smooth leaves, linear inner tepals spreading distally and filaments united for up to 1.5 mm. M. decipiens from the Piketberg, M. hainebachiana, a local endemic of coastal limestone fynbos in the Saldanha District, M. ogamana from seasonally wet lowlands, and early flowering M. mutila constitute the remaining species of the complex in the southwestern Western Cape. M. helmei, a local endemic of middle elevations in the Kamiesberg, Namaqualand, has small flowers with short, tricuspidate inner tepals. All but M. amabilis and M. mutila are new species. We divide M. tripetala sensu stricto into three subspecies: widespread subsp. tripetala, subsp. violacea from

  14. Taxonomic delimitation and drivers of speciation in the Ibero-North African Carex sect. Phacocystis river-shore group (Cyperaceae).

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    Jiménez-Mejías, Pedro; Escudero, Marcial; Guerra-Cárdenas, Samuel; Lye, Kåre A; Luceño, Modesto

    2011-11-01

    The Ibero-North African Carex sect. Phacocystis river-shore group is a set of perennial helophytic species with poorly defined taxonomic boundaries. In the present study, we delimited the different taxonomic units, addressed the phylogeographic history, and evaluated the drivers of differentiation that have promoted diversification of these plants. We analyzed molecular data using statistical parsimony for plastid sequences (26 samples from 26 populations) and principal coordinate analysis, neighbor joining, and Bayesian analysis of population structure for AFLPs (186 samples from 26 populations). Chromosome numbers from 14 samples (9 populations) are newly reported. Three species can be distinguished (C. acuta, C. elata, and C. reuteriana). Unexpectedly for rhizome-growing helophytes, the vegetative reproduction detected was incidental. The widespread C. elata was found to be a genetically poorly differentiated taxon, whereas the local C. reuteriana displayed geographical structuring. Geographical factors seem to be the main driver of differentiation for both taxa. Despite apparent morphological and ecological similarities, C. elata and C. reuteriana have disparate genetic structures and evolutionary histories, which may have originated from small ecological differences. Carex elata is broadly distributed throughout Europe, and its northern populations were recently founded, probably after the last glacial maximum. In contrast, C. reuteriana is an Ibero-North African endemic, with long-standing populations affected by isolation and limited gene flow. It is likely that high-density blocking effects and different gene-flow barriers act together to delimit its distribution and promote its relatively high population differentiation.

  15. Geology of the Sabie River Basalt Formation in the Southern Kruger National Park

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    R.J. Sweeney

    1986-12-01

    Full Text Available The Sabie River Basalt Formation (SRBF in the central Lebombo is a virtually continuous sequence of basaltic lavas some 2 500 m thick that was erupted 200 - 179 Ma ago. Flows are dominantly pahoehoe in character and vary from 2 m to 20 m in thickness. Dolerite dykes cross-cutting the basalt sequence probably represent feeders to this considerable volcanic event. Volcanological features observed within the SRBF are described. Two chemically distinct basaltic magma types are recognised, the simultaneous eruption of which presents an intriguing geochemical problem as to their origins.

  16. Annual cycle and composition of the phytoplankton in the Quempillen River Estuary, southern Chile

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    Toro, J. E.

    1985-10-01

    Phytoplankton species and abundance were studied in the Quempillen River Estuary, from August 1979 to July 1980 in addition to some important environmental factors: salinity, temperature and dissolved oxygen. In order to determine the seasonal variations in cell density and biomass of the phytoplankton in this brackish aquatic environment, phytoplankton data obtained by the Uthermöhl (1958) technique were analysed. A total of 109 phytoplankton species were identified within the samples. Throughout the year there were two periods of population maxima, September and May, and one period of high biomass, February. The phytoflagellates were always present but only dominated the flora when diatoms were extremely reduced, especially during low tide periods.

  17. Systematics of the southern African genus Ixia (Iridaceae. 2. The filiform-leaved I. capillaris complex

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    P. Goldblatt

    2008-12-01

    Full Text Available Field study and associated examination of herbarium specimens of the filiform-leaved species of section Morphixia o f the South African genus Ixia L. have resulted in an increase in the number of species with this derived leaf type.  Ixia capillaris and  I. pauciflora have until now been the only species with such leaves and they have not been regarded as immediately related in past accounts of the genus. The two foliage leaves, typically less than 2 mm w ide, with a leathery to succulent texture, and lacking a raised central vein or margins, are specialized in the genus. Associated finely fibrous corm tunics, spikes of 1-3 flowers, and when present, short, thread-like lateral branches, usually bearing 1 or 2 flowers, provide supporting evidence that the group is monophyletic.  I. capillaris as interpreted until now. comprises four species, three of them new and described here, and the large-flowered I. pauciflora includes two species, one of these described here. While I. capillaris has a branched stem, radially symmetric flowers with a penanth tube (4—5—7(—8 mm long, tepals 11-15 mm long and thus substantially exceeding the tube, filaments typically exserted 1-2 mm. and anthers (3—4—5 mm long. I. exiliflora has a tube 8-10 mm long and ± as long as the tepals, included filaments, and anthers 3.5—4.0 mm long. The new  I. dieramoides also has included filaments but a perianth tube 13—18(—22 mm long and tepals 11-18 mm long. A third new species. I. reclinata has large flowers with a tube 13-15 mm long, tepals 16-21 mm long, and unilateral, decimate stamens with the filaments exserted 8-10 mm. and anthers 4-5 mm long. Typical  I. pauciflora has flowers with unilateral stamens and filaments exserted 2-6 mm from the flower and anthers prominently displayed, but specimens until now included in that species w ith short, included filaments 3-5 mm long and anthers half included in the tube, are here regarded as I. dieramoides. The I

  18. Exploring Geochemical Markers of the Anthropocene in River Sediments: Southern New England

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    Tran, J.

    2015-12-01

    The sedimentary record of New England is complex. From glacial till to colonial land use to the industrial revolution, any sediment preserved is intertwined and muddled by humans. Recent studies support the idea that any anthropogenic markers in the sediment record are site specific. Southern New England is marked by a myriad of practices including farming, charcoal kilns, hatting, mill dams, and iron furnaces. While specific markers of the anthropocene have been identified, little work has been done to correlate and quantify these noted markers across multiple basins. Specifically, a combination of x-ray fluorescence (XRF), x-ray diffraction (XRD), and grain size analysis were done on sediment cores taken within Southern New England across various watersheds. We present a combination of geochemical analysis and detrital zircon geochronology in order identify and account for basin differences. This in turn results in a more comprehensive trans-basin understanding of the anthropocene in this region. We observe strong evidence that supports the idea of geochemical markers anthropocene which include an increase in Mercury and Lead content in the sediments. Additionally, in basins where mill dams are present we observe sediment records consistent with flood events and dam degradation. While still fairly novel and understudied, our results provide insight to the much often question topic of the anthropocene in relation to this particular region and the potential pitfalls of doing large scale anthropogenic dating.

  19. Early and late direct costs in a Southern African antiretroviral treatment programme: a retrospective cohort analysis.

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    Rory Leisegang

    2009-12-01

    Full Text Available BACKGROUND: There is a paucity of data on the health care costs of antiretroviral therapy (ART programmes in Africa. Our objectives were to describe the direct heath care costs and establish the cost drivers over time in an HIV managed care programme in Southern Africa. METHODS/FINDINGS: We analysed the direct costs of treating HIV-infected adults enrolled in the managed care programme from 3 years before starting non-nucleoside reverse transcriptase inhibitor-based ART up to 5 years afterwards. The CD4 cell count criterion for starting ART was <350 cells/microl. We explored associations between variables and mean total costs over time using a generalised linear model with a log-link function and a gamma distribution. Our cohort consisted of 10,735 patients (59.4% women with 594,497 mo of follow up data (50.9% of months on ART. Median baseline CD4+ cell count and viral load were 125 cells/microl and 5.16 log(10 copies/ml respectively. There was a peak in costs in the period around ART initiation (from 4 mo before until 4 mo after starting ART driven largely by hospitalisation, following which costs plateaued for 5 years. The variables associated with changes in mean total costs varied with time. Key early associations with higher costs were low baseline CD4+ cell count, high baseline HIV viral load, and shorter duration in HIV care prior to starting ART; whilst later associations with higher costs were lower ART adherence, switching to protease inhibitor-based ART, and starting ART at an older age. CONCLUSIONS: Drivers of mean total costs changed considerably over time. Starting ART at higher CD4 counts or longer pre-ART care should reduce early costs. Monitoring ART adherence and interventions to improve it should reduce later costs. Cost models of ART should take into account these time-dependent cost drivers, and include costs before starting ART. Please see later in the article for the Editors' Summary.

  20. Scrubbing Up: Multi-Scale Investigation of Woody Encroachment in a Southern African Savannah

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    Christopher G. Marston

    2017-04-01

    Full Text Available Changes in the extent of woody vegetation represent a major conservation question in many savannah systems around the globe. To address the problem of the current lack of broad-scale cost-effective tools for land cover monitoring in complex savannah environments, we use a multi-scale approach to quantifying vegetation change in Kruger National Park (KNP, South Africa. We test whether medium spatial resolution satellite data (Landsat, existing back to the 1970s, which have pixel sizes larger than typical vegetation patches, can nevertheless capture the thematic detail required to detect woody encroachment in savannahs. We quantify vegetation change over a 13-year period in KNP, examine the changes that have occurred, assess the drivers of these changes, and compare appropriate remote sensing data sources for monitoring change. We generate land cover maps for three areas of southern KNP using very high resolution (VHR and medium resolution satellite sensor imagery from February 2001 to 2014. Considerable land cover change has occurred, with large increases in shrubs replacing both trees and grassland. Examination of exclosure areas and potential environmental driver data suggests two mechanisms: elephant herbivory removing trees and at least one separate mechanism responsible for conversion of grassland to shrubs, theorised to be increasing atmospheric CO2. Thus, the combination of these mechanisms causes the novel two-directional shrub encroachment that we observe (tree loss and grassland conversion. Multi-scale comparison of classifications indicates that although spatial detail is lost when using medium resolution rather than VHR imagery for land cover classification (e.g., Landsat imagery cannot readily distinguish between tree and shrub classes, while VHR imagery can, the thematic detail contained within both VHR and medium resolution classifications is remarkably congruent. This suggests that medium resolution imagery contains sufficient

  1. CliFEM – Climate Forcing and Erosion Modelling in the Sele River Basin (Southern Italy

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    N. Diodato

    2009-10-01

    Full Text Available This study presents a revised and scale-adapted Foster-Meyer-Onstad model (Foster et al., 1977 for the transport of soil erosion sediments under scarce input data, with the acronym CliFEM (Climate Forcing and Erosion Modelling. This new idea was addressed to develop a monthly time scale invariant Net Erosion model (NER, with the aim to consider the different erosion processes operating at different time scales in the Sele River Basin (South Italy, during 1973–2007 period. The sediment delivery ratio approach was applied to obtain an indirect estimate of the gross erosion too. The examined period was affected by a changeable weather regime, where extreme events may have contributed to exacerbate soil losses, although only the 19% of eroded sediment was delivered at outlet of the basin. The long-term average soil erosion was very high (73 Mg ha−1 per year ± 58 Mg ha−1. The estimate of monthly erosion showed catastrophic soil losses during the soil tillage season (August–October, with consequent land degradation of the hilly areas of the Sele River Basin.

  2. Occurrence of pollution indicators in tropical perennial river of Periyar, Southern India

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    V. Mahesh

    2015-11-01

    Full Text Available The Periyar river water samples were collected from nine different places during summer 2015 for physiochemical and bacteriological analysis. The mean concentrations of DO (mg/L and BOD (mg/L in S1, S2, S3, S4, S5, S6, S7, S8 and S9 were 6.7 and 7.8, 5.8 and 8.1, 4.9 and 5.8, 5.6 and 6.3, 4.3 and 7.4, 8.0 and 9.1, 4.4 and 5.1, 3.4 and 6.8, and 5.1 and 3.8, respectively. The level of Pollution Index (PI (Fecal coliforms / Fecal Streptococci in S1, S2, S3, S4, S5, S6, S7, S8 and S9 was 1.8, 1.3, 2.1, 1.75, 2.4, 1.8, 2.3, 1.4 and 1.5, respectively. The higher PI ratio (>1 indicated that the sampling sites were contaminated by human fecal matters which is major contribution for river pollution and which require immediate attention. The study further raises points for the need of action for a sustainable utilization of precious resources. The study also recommends the necessity of proper sanitation and waste disposal to sustain the surface water quality.

  3. Commissioning MOS and Fabry-Perot modes for the Robert Stobie Spectrograph on the Southern African Large Telescope

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    Koeslag, A. R.; Williams, T. B.; Nordsieck, K. H.; Romero-Colmenero, E.; Vaisanen, P. H.; Maartens, D. S.

    2014-07-01

    The Southern African Large Telescope (SALT) currently has three instruments: the imaging SALTICAM, the new High Resolution Spectrograph (HRS) which is in the process of being commissioned and the Robert Stobie Spectrograph (RSS). RSS has multiple science modes, of which long slit spectroscopy was originally commissioned; We have commissioned two new science modes: Multi Object Spectroscopy (MOS) and Fabry-Perot (FP). Due to the short track times available on SALT it is vital that acquisition is as efficient as possible. This paper will discuss how we implemented these modes in software and some of the challenges we had to overcome. MOS requires a slit-mask to be aligned with a number of stars. This is done in two phases: in MOS calibration the positions of the slits are detected using a through-slit image and RA/DEC database information, and in MOS acquisition the detector sends commands to the telescope control system (TCS) in an iterative and interactive fashion for fine mask/detector alignment to get the desired targets on the slits. There were several challenges involved with this system, and the user interface evolved to make the process as efficient as possible. We also had to overcome problems with the manufacturing process of the slit-masks. FP requires the precise alignment each of the two etalons installed on RSS. The software makes use of calibration tables to get the etalons into roughly aligned starting positions. An exposure is then done using a calibration arc lamp, producing a ring pattern. Measurement of the rings allows the determination of the adjustments needed to properly align the etalons. The software has been developed to optimize this process, along with software tools that allow us to fine tune the calibration tables. The software architecture allows the complexity of automating the FP calibration and procedures to be easily managed.

  4. Integrating remote sensing and conventional grazing/browsing models for modelling carrying capacity in southern African rangelands

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    Adjorlolo, C.; Botha, J. O.; Mhangara, P.; Mutanga, O.; Odindi, J.

    2014-10-01

    Woody vegetation encroachment into grasslands or bush thickening, a global phenomenon, is transforming the Southern African grassland systems into savanna-like landscapes. Estimation of woody vegetation is important to rangeland scientists and land managers for assessing its impact on grass production and calculating its grazing and browsing capacity. Assessment of grazing and browsing components is often challenging because agro-ecological landscapes of this region are largely characterized by small scale and heterogeneous land-use-land-cover patterns. In this study, we investigated the utility of high spatial resolution remotely sensing data for modelling grazing and browsing capacity at landscape level. Woody tree density or Tree Equivalents (TE) and Total Leaf Mass (LMASS) data were derived using the Biomass Estimation for Canopy Volume (BECVOL) program. The Random Forest (RF) regression algorithm was assessed to establish relationships between these variables and vegetation indices (Simple Ratio and Normalized Difference Vegetation Index), calculated using the red and near infrared bands of SPOT5. The RF analysis predicted LMASS with R2 = 0.63 and a Root Mean Square Error (RMSE) of 1256 kg/ha compared to a mean of 2291kg/ha. TE was predicted with R2 = 0.55 and a RMSE = 1614 TE/ha compared to a mean of 3746 TE/ha. Next, spatial distribution maps of LMASS/ha and TE/ha were derived using separate RF regression models. The resultant maps were then used as input data into conventional grazing and browsing capacity models to calculate grazing and browsing capacity maps for the study area. This study provides a sound platform for integrating currently available and future remote sensing satellite data into rangeland carrying capacity modelling and monitoring.

  5. Regional trade and the nutrition transition: opportunities to strengthen NCD prevention policy in the Southern African Development Community.

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    Thow, Anne Marie; Sanders, David; Drury, Eliza; Puoane, Thandi; Chowdhury, Syeda N; Tsolekile, Lungiswa; Negin, Joel

    2015-01-01

    Addressing diet-related non-communicable diseases (NCDs) will require a multisectoral policy approach that includes the food supply and trade, but implementing effective policies has proved challenging. The Southern African Development Community (SADC) has experienced significant trade and economic liberalization over the past decade; at the same time, the nutrition transition has progressed rapidly in the region. This analysis considers the relationship between regional trade liberalization and changes in the food environment associated with poor diets and NCDs, with the aim of identifying feasible and proactive policy responses to support healthy diets. Changes in trade and investment policy for the SADC were documented and compared with time-series graphs of import data for soft drinks and snack foods to assess changes in imports and source country in relation to trade and investment liberalization. Our analysis focuses on regional trade flows. Diets and the burden of disease in the SADC have changed since the 1990s in parallel with trade and investment liberalization. Imports of soft drinks increased by 76% into SADC countries between 1995 and 2010, and processed snack foods by 83%. South Africa acts as a regional trade and investment hub; it is the major source of imports and investment related to these products into other SADC countries. At the same time, imports of processed foods and soft drinks from outside the region - largely from Asia and the Middle East - are increasing at a dramatic rate with soft drink imports growing by almost 1,200% and processed snack foods by 750%. There is significant intra-regional trade in products associated with the nutrition transition; however, growing extra-regional trade means that countries face new pressures in implementing strong policies to prevent the increasing burden of diet-related NCDs. Implementation of a regional nutrition policy framework could complement the SADC's ongoing commitment to regional trade policy.

  6. Regional trade and the nutrition transition: opportunities to strengthen NCD prevention policy in the Southern African Development Community

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    Anne Marie Thow

    2015-07-01

    Full Text Available Background: Addressing diet-related non-communicable diseases (NCDs will require a multisectoral policy approach that includes the food supply and trade, but implementing effective policies has proved challenging. The Southern African Development Community (SADC has experienced significant trade and economic liberalization over the past decade; at the same time, the nutrition transition has progressed rapidly in the region. This analysis considers the relationship between regional trade liberalization and changes in the food environment associated with poor diets and NCDs, with the aim of identifying feasible and proactive policy responses to support healthy diets. Design: Changes in trade and investment policy for the SADC were documented and compared with time-series graphs of import data for soft drinks and snack foods to assess changes in imports and source country in relation to trade and investment liberalization. Our analysis focuses on regional trade flows. Results: Diets and the burden of disease in the SADC have changed since the 1990s in parallel with trade and investment liberalization. Imports of soft drinks increased by 76% into SADC countries between 1995 and 2010, and processed snack foods by 83%. South Africa acts as a regional trade and investment hub; it is the major source of imports and investment related to these products into other SADC countries. At the same time, imports of processed foods and soft drinks from outside the region – largely from Asia and the Middle East – are increasing at a dramatic rate with soft drink imports growing by almost 1,200% and processed snack foods by 750%. Conclusions: There is significant intra-regional trade in products associated with the nutrition transition; however, growing extra-regional trade means that countries face new pressures in implementing strong policies to prevent the increasing burden of diet-related NCDs. Implementation of a regional nutrition policy framework could

  7. An Approach for Including Uncertainty in Integrated Water Resources Assessments within Large River Basins of Southern Africa.

    Science.gov (United States)

    Hughes, D.

    2015-12-01

    There are many large basins in southern Africa that are mostly ungauged but may have some streamflow observations either on the main river or on tributaries. Many of the streamflow records are, however, of poor quality or impacted by largely unquantified and non-stationary development impacts. All water resources assessments are therefore uncertain and model setups are difficult to validate in traditional ways. The paper presents a method for practical uncertainty assessment using a semi-distributed (sub-basin) model. The method uses a 2-stage approach where the first stage involves obtaining 'behavioural' parameter sets to represent the incremental natural streamflow for each sub-basin. The criteria for 'behavioural' are based on a series of constraints on model output that can be developed from the available gauged data or from regional assessments of natural hydrological functioning. The second stage simulates the whole basin based on sampling the 'behavioural' incremental flow parameter sets, as well as samples of additional individual parameter values representing downstream routing parts of the model and development impacts. One of the perceived advantage of the method is that all the ensembles at the total basin outlet are made up of behavioural inputs for all sub-basins. The method is also flexible in terms of the uncertainty range of the constraints, which might be expected to be narrow (low uncertainty) in well gauged sub-basins, or areas where our understanding of flow regime characteristics is good, but much wider (higher uncertainty) in other parts of the basin. The paper briefly explains the approach and discusses some of the issues associated with its application using examples from southern Africa.

  8. Fluvial landscapes evolution in the Gangkou River basin of southern Taiwan: Evidence from the sediment cores

    Science.gov (United States)

    Chen, Jia-Hong; Chyi, Shyh-Jeng; Yen, Jiun-Yee; Lin, Li-Hung; Yen, I.-Chin; Yu, Neng-Ti; Ho, Lih-Der; Jen, Chia-Hung

    2017-04-01

    The Gangkou River basin is the largest basin in the eastern Hengchun Peninsula of Taiwan. Its main river length is 31km and the basin area is 102sq. km. The width of the active channel is relatively narrow, but the valley from the middle to downstream is remarkably wide, indicating a feature of underfit stream. We drilled two sediment cores in the downstream area, including a 30m core (core-A) from a higher terrace, which is 14m above mean sea level, and a 20m core (core-B) from a lower terrace, which is 4m above mean sea level. Most of the sediments in the core-A are mud, which represents the flood plain facies, and 14C dates in the core-A range from 11ka to 7ka BP. Furthermore, the sediment layers reveal signals of marine events at the core depths of 5m to 11m by X-ray fluorescence. In the core-B, there is an erosional surface at the core depth of 5m. The age of the fluvial gravel layer above the erosional surface is about 0.4ka BP, and the mud layer top the surface is about 8.5ka BP. The preliminary results show that (1) as the tectonic uplift rate induced by the marine terraces around the basin is 1.0 to 2.5 mm/yr, and the accumulation rate of the mud layer in the basin is 6.7 to 8.7 mm/yr, the sediments infilling (more than 30-meters-thick) in the downstream area of the basin should be the results of the lower tectonic uplifting and the higher post-glacial sea level rise and; (2) the marine sediment layer with 14C dates of 7.5ka to 8.5ka BP is very likely the remain of the maximum flooding surface (MFS) in the early Holocene. These results indicate that the fluvial landscapes evolution of the basin was controlled by the sea-level; (3) the erosional surface in the core-B indicates the Gangkou River continuously erode the infilling sediments from 7ka to 0.4ka BP. Previous studies show that the sea-level around Taiwan gradually declined from its high stand since 6ka, we proposed that the continuous erosion was probably the results of tectonic uplifting and

  9. Landscape development in Southern Peninsular India from 10Be denudation rates in river sands

    Science.gov (United States)

    Mandal, Sanjay; Lupker, Maarten; Haghipour, Negar; Burg, Jean-Pierre; Christl, Marcus

    2014-05-01

    The persistence of high elevation and topography observed along many passive margins remains one of the outstanding problems in landscape evolution. In Southern Peninsular India, this question revolves around the understanding of whether the observed high relief and pronounced topography results from equilibrium with contemporaneous external forcing or whether the relief was acquired during the late Cenozoic and conserved over several tens of millions years. Modern denudation rates dictating the current landscape evolution are ruled by the interactions between climate, tectonics and rock strength. We used detrital cosmogenic 10Be from 43 drainage basins ranging in size from 4 to 68768 km2, to infer millennial averaged denudation rates along and across the Western Ghat Mountains in Southern India and to understand if the present landscape is still actively evolving or not. The Western Ghat is characterized by a W-E gradient in relief and rainfall with only minor variations in lithology allowing to isolate the relationship between erosion rates and topographic indices. Cosmogenic-derived erosion rates are spatially variable, ranging from ~8 to 77 mm/ka on the western side and 8 to 51 mm/ka on the eastern side. The rugged topography of Western Ghats and Nilgiri Mountains exhibit pronounced topography in conjunction with low denudation rates. This represents an exception to the often-cited general coupling of topography and denudation rates and suggests that steep slopes and high relief in passive margin settings are not associated to high denudation. Nevertheless, locally the differences in denudation rates along and across the Western Ghats are well correlated with local relief, which suggests that the inherited topography still controls current denudation rates. Even though the catchments in Western Ghats receive a mean annual precipitation ~ 5 m, due to the SW Indian monsoon, precipitation shows only a minor control on denudation rates. This suggests that in the

  10. Oscillations and trends of river discharge in the southern Central Andes and linkages with climate variability

    Science.gov (United States)

    Castino, Fabiana; Bookhagen, Bodo; Strecker, Manfred R.

    2017-12-01

    This study analyzes the discharge variability of small to medium drainage basins (102-104 km2) in the southern Central Andes of NW Argentina. The Hilbert-Huang Transform (HHT) was applied to evaluate non-stationary oscillatory modes of variability and trends, based on four time series of monthly-normalized discharge anomaly between 1940 and 2015. Statistically significant trends reveal increasing discharge during the past decades and document an intensification of the hydrological cycle during this period. An Ensemble Empirical Mode Decomposition (EEMD) analysis revealed that discharge variability in this region can be best described by five quasi-periodic statistically significant oscillatory modes, with mean periods varying from 1 to ∼20 y. Moreover, we show that discharge variability is most likely linked to the phases of the Pacific Decadal Oscillation (PDO) at multi-decadal timescales (∼20 y) and, to a lesser degree, to the Tropical South Atlantic SST anomaly (TSA) variability at shorter timescales (∼2-5 y). Previous studies highlighted a rapid increase in discharge in the southern Central Andes during the 1970s, inferred to have been associated with the global 1976-77 climate shift. Our results suggest that the rapid discharge increase in the NW Argentine Andes coincides with the periodic enhancement of discharge, which is mainly linked to a negative to positive transition of the PDO phase and TSA variability associated with a long-term increasing trend. We therefore suggest that variations in discharge in this region are largely driven by both natural variability and the effects of global climate change. We furthermore posit that the links between atmospheric and hydrologic processes result from a combination of forcings that operate on different spatiotemporal scales.

  11. Inter-annual and Intra-annual Variability in River Flow and Inundation in African River Systems: Results from a new pan-African Land-surface Model Validated against Earth Observations

    Science.gov (United States)

    Dadson, S. J.

    2014-12-01

    The role of surface-water flooding in controlling fluxes of water and carbon between the land and the atmosphere is increasingly recognized in studies of the Earth system. Simultaneous advances in remote earth observation and large-scale land-surface and hydrological modeling promise improvements in our ability to understand these linkages, and suggest that improvements in prediction of river flow and inundation extents may result. Here we present an analysis of newly-available observational estimates of surface water inundation obtained through satellite Earth observation with results from simulations produced by using the Joint UK Land Environment Simulator (JULES) land-surface model operating at 0.5 degree resolution over the African continent. The model was forced with meteorological input from the WATCH Forcing Data for the period 1981-2001 and sensitivity to various model configurations and parameter settings were tested. Both the PDM and TOPMODEL sub-grid scale runoff generation schemes were tested for parameter sensitivities, with the evaluation focussing on simulated river discharge in sub-catchments of the Congo, Nile, Niger, Orange, Okavango and Zambezi rivers. It was found that whilst the water balance in each of the catchments can be simulated with acceptable accuracy, the individual responses of each river vary between model configurations so that there is no single runoff parameterization scheme or parameter values that yields optimal results across all catchments. We trace these differences to the model's representation of sub-surface flow and make some suggestions to improve the performance of large-scale land-surface models for use in similar applications. Our findings also demonstrate links between episodes of extensive surface water flooding and large-scale climatic indices, although the pattern of correlations contains a level of spatial and temporal detail that warrants careful attention to the climatology of individual situations. These

  12. Flow-gauging structures in South African rivers Part 2: Calibration ...

    African Journals Online (AJOL)

    Accurate hydrological information is of paramount importance in a dry country such as South Africa. Flow measurements in rivers are complicated by the high variability of flows as well as by sediment loads and debris. It has been found necessary to modify and even substitute certain internationally accepted gauging station ...

  13. 'Beyond the rivers of Ethiopia' : Pentecostal Pan-Africanism and Ghanaian identities in the transnational domain

    NARCIS (Netherlands)

    Dijk, van R.A.

    2004-01-01

    Rev. Mensa Otabil, the founder of the International Central Gospel Church in Accra, is considered an influential representative of a new Pentecostal-inspired Pan-Africanist ideology. His book 'Beyond the Rivers of Ethiopia' lays the foundations of a Pentecostal Liberation Theology that proclaims a

  14. The Aquatic And Marshy Flora Of The Lotru River Basin (Southern Carpathians, Romania

    Directory of Open Access Journals (Sweden)

    Drăgulescu Constantin

    2014-10-01

    Full Text Available The present paper continues the series of floristic inventories of the main Romanian rivers in the Carpathian Mountains (from which have been published those of Mureş, Sadu, Olt, Someş, Criş, Târnave, Tisa. In this work the author lists 204 plant taxa (hydrophilic, meso-hygrophilic and hygrophilic identified by the author or by other botanists in the Lotru Valley basin. Noted for each species were life form, floral element, ecological preferences for humidity (U, temperature (T, soil reaction (R, corology and coenology. Bibliographical sources are coded with numbers (see the references at the end of the paper. The sign “!” indicates that the author has seen the plant in that locality.

  15. The influence of El Niño–Southern Oscillation regimes on eastern African vegetation and its future implications under the RCP8.5 warming scenario

    Directory of Open Access Journals (Sweden)

    I. Fer

    2017-09-01

    Full Text Available The El Niño–Southern Oscillation (ENSO is the main driver of the interannual variability in eastern African rainfall, with a significant impact on vegetation and agriculture and dire consequences for food and social security. In this study, we identify and quantify the ENSO contribution to the eastern African rainfall variability to forecast future eastern African vegetation response to rainfall variability related to a predicted intensified ENSO. To differentiate the vegetation variability due to ENSO, we removed the ENSO signal from the climate data using empirical orthogonal teleconnection (EOT analysis. Then, we simulated the ecosystem carbon and water fluxes under the historical climate without components related to ENSO teleconnections. We found ENSO-driven patterns in vegetation response and confirmed that EOT analysis can successfully produce coupled tropical Pacific sea surface temperature–eastern African rainfall teleconnection from observed datasets. We further simulated eastern African vegetation response under future climate change as it is projected by climate models and under future climate change combined with a predicted increased ENSO intensity. Our EOT analysis highlights that climate simulations are still not good at capturing rainfall variability due to ENSO, and as we show here the future vegetation would be different from what is simulated under these climate model outputs lacking accurate ENSO contribution. We simulated considerable differences in eastern African vegetation growth under the influence of an intensified ENSO regime which will bring further environmental stress to a region with a reduced capacity to adapt effects of global climate change and food security.

  16. African Journals Online (AJOL)

    African Journals Online (AJOL)

    African Journals OnLine (AJOL) is the world's largest and pre-eminent collection of peer-reviewed, African-published scholarly journals. Historically, scholarly information has flowed from ... Southern African Business Review; Conflicts in Africa: Meaning, Causes, Impact and Solution African Research Review; The abnormal ...

  17. African Journals Online (AJOL)

    African Journals Online (AJOL)

    African Research Review; The competitive advantage of nations: is Porter's Diamond Framework a new theory that explains the international competitiveness of countries? Southern African Business Review; The Rise of Independent African Churches, 1890-1930: An Ethical-genesis of Nigerian Nationalism African ...

  18. African Journals Online (AJOL)

    African Journals Online (AJOL)

    Featured Country: Nigeria, Featured Journal: African Journal of Endocrinology and Metabolism ... Southern African Business Review; The Basis of Distinction Between Qualitative and Quantitative Research in Social Science: Reflection on Ontological, Epistemological and Methodological Perspectives Ethiopian Journal of ...

  19. African Journals Online (AJOL)

    African Journals Online (AJOL)

    African Journals OnLine (AJOL) is the world's largest and pre-eminent collection of ... Ethiopian Journal of Education and Sciences; The competitive advantage of ... Southern African Business Review; Income Tax Assignment under the ...

  20. African Journals Online (AJOL)

    African Journals Online (AJOL)

    reviewed, African-published scholarly journals. Historically, scholarly information has flowed from North to South and from West to East. ... Featured Country: South Africa, Featured Journal: Southern African Linguistics and Applied Language Studies ...

  1. African Journals Online (AJOL)

    African Journals Online (AJOL)

    Southern African Business Review; Project Work by Students for First Degree: An Appraisal Nnamdi ... African Research Review; Powers and Duties of the Corporate Affairs ... International Journal of Development and Management Review.

  2. Water quality assessment in the ?German River of the years 2014/2015?: how a case study on the impact of a storm water sedimentation basin displayed impairment of fish health in the Argen River (Southern Germany)

    OpenAIRE

    Thellmann, Paul; Kuch, Bertram; Wurm, Karl; K?hler, Heinz-R; Triebskorn, Rita

    2017-01-01

    Background The present work investigates the impact of discharges from a storm water sedimentation basin (SSB) receiving runoff from a connected motorway in southern Germany. The study lasted for almost two years and was aimed at assessing the impact of the SSB on the fauna of the Argen River, which is a tributary of Lake Constance. Two sampling sites were examined up- and downstream of the SSB effluent. A combination of different diagnostic methods (fish embryo test with the zebrafish, histo...

  3. River-Basin Politics and the Rise of Ecological and Transnational Democracy in Southeast Asia and Southern Africa

    Directory of Open Access Journals (Sweden)

    Chris Sneddon

    2008-06-01

    Full Text Available In recent years, debates over 'deliberative', 'transnational' and 'ecological' democracy have proliferated, largely among scholars engaged in discussions of modernisation, globalisation and political identity. Within this broad context, scholars and practitioners of environmental governance have advanced the argument that a democratic society will produce a more environmentally conscious society. We want to make a volte-face of this argument and ask: to what extent does engagement with environmental politics and, specifically, water politics, contribute to processes of democratisation? After reviewing some of the contributions to debates over 'ecological' and 'transnational' democracy, we explore this question within the context of conflicts over river-basin development in Southeast Asia and southern Africa. We argue that there are multiple pathways to democratisation and that, in some cases, the environment as a political issue does constitute a significant element of democratisation. But notions of 'ecological' and 'transnational' democracy must embody how both 'environment' and 'the transnational', as mobilised by specific social movements in specific historical and geographical circumstances, are politically constructed.

  4. Historical Storminess and Hydro-Geological Hazard Temporal Evolution in the Solofrana River Basin—Southern Italy

    Directory of Open Access Journals (Sweden)

    Antonia Longobardi

    2016-09-01

    Full Text Available Precipitation extremes have always been part of the Earth’s climate system and associated multiple damaging hydrological events (MDHEs, the simultaneous triggering of different types of phenomena (landslides and floods, affect an always-increasing portion of human settlement areas. This paper aims to investigate the relationship between the temporal evolution of severe geomorphological events and combined precipitation indices as a tool to improve understanding the hydro-geological hazard at the catchment scale. The case study is the Solofrana river basin, Southern Italy, and the focus is on four of main municipalities severely affected by natural disasters. Data for about 45 MDH events, spanning 1951–2014, have been collected and analyzed for this purpose. A preliminary monthly scale analysis of event occurrences highlights a pronounced seasonal characterization of the phenomenon, as about 60% of the total number of reported events take place during the period from September to November. Following, a statistical analysis clearly indicates a significant increase in the frequency of occurrences of MDHEs during the last decades. Such an increase appears to be related to non-stationary features of an average catchment scale rainfall-runoff erosivity index, which combines maximum monthly, maximum daily, and a proxy of maximum hourly precipitation data.

  5. Predictors of occurrence of the aquatic macrophyte Podostemum ceratophyllum in a southern Appalachian River

    Science.gov (United States)

    Argentina, Jane E.; Freeman, Mary C.; Freeman, Byron J.

    2010-01-01

    The aquatic macrophyte Podostemum ceratophyllum (Hornleaf Riverweed) commonly provides habitat for invertebrates and fishes in flowing-water portions of Piedmont and Appalachian streams in the eastern US. We quantified variation in percent cover by P. ceratophyllum in a 39-km reach of the Conasauga River, TN and GA, to test the hypothesis that cover decreased with increasing non-forest land use. We estimated percent P. ceratophyllum cover in quadrats (0.09 m2) placed at random coordinates within 20 randomly selected shoals. We then used hierarchical logistic regression, in an information-theoretic framework, to evaluate relative support for models incorporating alternative combinations of microhabitat and shoal-level variables to predict the occurrence of high (≥50%)P. ceratophyllum cover. As expected, bed sediment size and measures of light availability (location in the center of the channel, canopy cover) were included in best-supported models and had similar estimated-effect sizes across models. Podostemum ceratophyllum cover declined with increasing watershed size (included in 8 of 13 models in the confidence set of models); however, this decrease in cover was not well predicted by variation in land use. Focused monitoring of temporal and spatial trends in status of P. ceratophyllum are important due to its biotic importance in fast-flowing waters and its potential sensitivity to landscape-level changes, such as declines in forested land cover and homogenization of benthic habitats.

  6. Air temperature change in the southern Tarim River Basin, China, 1964-2011.

    Science.gov (United States)

    Zhao, Benfu; Xu, Jianhua; Chen, Zhongsheng; Bai, Ling; Li, Peng

    2013-01-01

    The temperature data from 3 meteorological stations (Kashi, Ruoqiang, and Hotan) in the South of Tarim River Basin (STRB) during 1964-2011 were analyzed by Mann-Kendall test and correlation analysis. The results from Mann-Kendall test show that the surface temperature (ST), 850 hPa temperature (T850), and 700 hPa temperature (T700) exhibited upward trends, while 300 hPa temperature (T300) revealed a downward trend. On the whole, the change rate of ST, T850, T700, and T300 was 0.26~0.46°C/10a, 0.15~0.40°C/10a, 0.03~0.10°C/10a, and -0.38~-0.13°C/10a, respectively. For the periods, ST and T850 declined during 1964-1997 and then rose during 1998-2011. T700 declined during 1964-2005 and then rose during 2006-2011, while T300 rose from 1964 to 1970s and then declined. The results from correlation analysis show that T850 and T700 positively correlated with ST (P<0.01) at the all three stations and there was a negative correlation between T300 and ST at Hotan (P<0.1), while the correlation is not significant at Kashi and Ruoqiang. The results indicate that there were gradient differences in the response of upper-air temperature (UT) to ST change.

  7. Satellite-measured interannual variability of turbid river plumes off central-southern Chile: Spatial patterns and the influence of climate variability

    Science.gov (United States)

    Saldías, Gonzalo S.; Largier, John L.; Mendes, Renato; Pérez-Santos, Iván; Vargas, Cristian A.; Sobarzo, Marcus

    2016-08-01

    Ocean color imagery from MODIS (Moderate Resolution Imaging Spectroradiometer) onboard the Aqua platform is used to characterize the interannual variability of turbid river plumes off central-southern Chile. Emphasis is placed on the influence of climate fluctuations, namely El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), and the Antarctic Oscillation (AAO). Additional satellite data on wind, boat-based hydrographic profiles, and regional climate indices are used to identify the influence of climate variability on the generation of anomalous turbid river plumes. The evolution of salinity at a coastal station on the 90 m isobath between the Itata and Biobío Rivers shows a freshwater surface layer with salinity < 32.5 and 5-10 m thick during major plume events in 2002, 2005 and 2006. Surface salinity minima are correlated with peaks in turbidy from the normalized water leaving radiance at 555 nm (nLw(555)), both representing turbid river plumes. EOF analysis reveals that major turbid plume events occurred primarily during warm phases of the ENSO and PDO, and negative phases of the AAO, when storm tracks are further north. Anomalously large turbid plumes extend long distances offshore (∼ 70-80 km), and individual plumes coalesce into a continuous plume along the coast that covers the entire continental shelf. Season-specific correlation analyses reveal an increased influence of the AAO on river plumes south of Punta Lavapié in spring-summer (negative correlation). North of this major cape, ENSO and PDO indices have a dominant influence on plumes with positive correlations with the nLw(555) signal in winter (and negative in summer). We discuss the biogeochemical implications of plume events and the importance of long-term and high-resolution ocean color observations for studying the temporal evolution of river plumes.

  8. Biomarkers of Oxidative Stress and Heavy Metal Levels as Indicators of Environmental Pollution in African Cat Fish (Clarias gariepinus) from Nigeria Ogun River

    OpenAIRE

    Y. R. Ajimoko; O. A. Adelowo; Farombi, E. O.

    2007-01-01

    Levels of Zn, Cu, Cd, As, and Pb in the kidney, Liver, Gills and Heart of African cat fish (Clarias gariepinus) from the Ogun River in Ogun State located close to six major industries in the South Western part of Nigeria, were determined using Bulk Scientific Atomic Absorption Spectrophotometer. Fishes were also collected from Government owned fish farm in Agodi, Ibadan which was considered a reference site. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione S-transfera...

  9. Air Temperature Change in the Southern Tarim River Basin, China, 1964–2011

    Directory of Open Access Journals (Sweden)

    Benfu Zhao

    2013-01-01

    Full Text Available The temperature data from 3 meteorological stations (Kashi, Ruoqiang, and Hotan in the South of Tarim River Basin (STRB during 1964–2011 were analyzed by Mann-Kendall test and correlation analysis. The results from Mann-Kendall test show that the surface temperature (ST, 850 hPa temperature (T850, and 700 hPa temperature (T700 exhibited upward trends, while 300 hPa temperature (T300 revealed a downward trend. On the whole, the change rate of ST, T850, T700, and T300 was 0.26~0.46°C/10a, 0.15~0.40°C/10a, 0.03~0.10°C/10a, and −0.38~−0.13°C/10a, respectively. For the periods, ST and T850 declined during 1964–1997 and then rose during 1998–2011. T700 declined during 1964–2005 and then rose during 2006–2011, while T300 rose from 1964 to 1970s and then declined. The results from correlation analysis show that T850 and T700 positively correlated with ST (P<0.01 at the all three stations and there was a negative correlation between T300 and ST at Hotan (P<0.1, while the correlation is not significant at Kashi and Ruoqiang. The results indicate that there were gradient differences in the response of upper-air temperature (UT to ST change.

  10. Air Temperature Change in the Southern Tarim River Basin, China, 1964–2011

    Science.gov (United States)

    Zhao, Benfu; Chen, Zhongsheng; Li, Peng

    2013-01-01

    The temperature data from 3 meteorological stations (Kashi, Ruoqiang, and Hotan) in the South of Tarim River Basin (STRB) during 1964–2011 were analyzed by Mann-Kendall test and correlation analysis. The results from Mann-Kendall test show that the surface temperature (ST), 850 hPa temperature (T850), and 700 hPa temperature (T700) exhibited upward trends, while 300 hPa temperature (T300) revealed a downward trend. On the whole, the change rate of ST, T850, T700, and T300 was 0.26~0.46°C/10a, 0.15~0.40°C/10a, 0.03~0.10°C/10a, and −0.38~−0.13°C/10a, respectively. For the periods, ST and T850 declined during 1964–1997 and then rose during 1998–2011. T700 declined during 1964–2005 and then rose during 2006–2011, while T300 rose from 1964 to 1970s and then declined. The results from correlation analysis show that T850 and T700 positively correlated with ST (P < 0.01) at the all three stations and there was a negative correlation between T300 and ST at Hotan (P < 0.1), while the correlation is not significant at Kashi and Ruoqiang. The results indicate that there were gradient differences in the response of upper-air temperature (UT) to ST change. PMID:24348192

  11. The extent of the Cratonic keel underneath the Southern African region: A 3D image using Finite-Frequency Tomography

    Science.gov (United States)

    Youssof, M.; Bezada, M.; Thybo, H.; Levander, A.

    2010-12-01

    We have re-examined the P body wave data from the South Africa Seismic Experiment (Carlson et al, EOS 77, 1996) across the Kaapvaal and Zimbabwe cratons and the Bushveld complex. Using finite-frequency kernels, we inverted the P-wave delay times to obtain 3-D images of compressional velocity perturbations in the mantle beneath the Southern African cratons to depths as great as the bottom of the transition zone. We utilized P-wave cross-correlation arrival times at three different frequency bands 1, 0.5 and 0.25 Hz. All P-wave arrivals were hand-processed. Crustal corrections were calculated using a crustal model we derived from PdS receiver functions using H-K analysis (Zhu and Kanamori, J. Geophys. Res. 105, 2000), and varied with azimuth. We chose damping for the inversion by examining the model norm-data misfit L curve. Checkerboard resolution tests showed good model recovery for 8°x8° anomalies with Vp variations of ±1.5%; 4°X4° checkerboards showed moderately good recovery. To try to isolate the depth extent of anomalies in the model we ran two suites of squeezing tests: 1) We reduced the maximum depth of the model from 1000 to 700 to 410 km. 2) For a 1000 km deep model we increased the damping parameter in the deeper layers progressively and examined the rms misfit and the imaged structure. Visual inspection of the tomographic images produced from these inversions showed that the lateral distribution of structures remained unchanged as the depth of the model was reduced and deep structures persist even with large damping, but with the rms error changing significantly. This indicates to us that the deeper structures are real. We have obtained a new P-wave tomography model showing the depth extent of the cratonic keel. We can distinguish the lateral and the vertical extent in Vp variations between the Archean and modified regions such as the Bushveld complex, and the mobile belts surrounding the cratons. The high velocity (+1.0%) cratonic roots extend to

  12. CSP parabolic trough and power tower performance analysis through the Southern African universities radiometric network (SAURAN) data

    Science.gov (United States)

    Pidaparthi, A. S.; Dall, E. P.; Hoffmann, J. E.; Dinter, F.

    2016-05-01

    The objective of this paper is to analyse the performance of parabolic trough and power tower technologies by selecting two radiometric stations in different geographic locations, with approximately equal annual direct normal irradiance (DNI) values, but with different monthly DNI distributions. The two stations chosen for this study are situated at the University of Free State, Bloemfontein, Free State Province and in Vanrhynsdorp, Western Cape Province. The annual measured DNI values for both these locations in South Africa are in the range of 2500-2700 kWh/m2. The comparison between the different monthly DNI distributions of these selected sites includes an assessment of annual hourly data in order to study the performance analysis of the most mature concentrating solar power (CSP) technologies, namely parabolic trough and power tower plants. The weather data has been obtained from the Southern African Universities Radiometric Network (SAURAN). A comparison between the different monthly DNI distributions of these selected sites includes the assessment of hourly data. Selection of these radiometric stations has also been done on the basis that they have been operational for at least one year. The first year that most SAURAN stations have been online for at least one year is 2014, thus data from this year has been considered. The annual performance analysis shows that parabolic trough plants have a higher energy yield in Vanrhynsdorp while power tower plants seem to be more suitable for Bloemfontein. Power tower plants in both the locations have a higher annual energy yield when compared with parabolic trough plants. A parabolic trough power plant in Vanrhynsdorp in the Western Cape Province has very low monthly electricity generation in the winter months of May, June, July and August. This is partly due to the higher cosine losses in the parabolic trough `one-axis' tracking systems and lower DNI values in the winter months. However, a power tower plant in

  13. Evaluating LSM-Based Water Budgets Over a West African Basin Assisted with a River Routing Scheme

    Science.gov (United States)

    Getirana, Augusto C. V.; Boone, Aaron; Peugeot, Christophe

    2014-01-01

    Within the framework of the African Monsoon Multidisciplinary Analysis (AMMA) Land Surface Model Intercomparison Project phase 2 (ALMIP-2), this study evaluates the water balance simulated by the Interactions between Soil, Biosphere, and Atmosphere (ISBA) over the upper Oum River basin, in Benin, using a mesoscale river routing scheme (RRS). The RRS is based on the nonlinear Muskingum Cunge method coupled with two linear reservoirs that simulate the time delay of both surface runoff and base flow that are produced by land surface models. On the basis of the evidence of a deep water-table recharge in that region,a reservoir representing the deep-water infiltration (DWI) is introduced. The hydrological processes of the basin are simulated for the 2005-08 AMMA field campaign period during which rainfall and stream flow data were intensively collected over the study area. Optimal RRS parameter sets were determined for three optimization experiments that were performed using daily stream flow at five gauges within the basin. Results demonstrate that the RRS simulates stream flow at all gauges with relative errors varying from -22% to 3% and Nash-Sutcliffe coefficients varying from 0.62 to 0.90. DWI varies from 24% to 67% of the base flow as a function of the sub-basin. The relatively simple reservoir DWI approach is quite robust, and further improvements would likely necessitate more complex solutions (e.g., considering seasonality and soil type in ISBA); thus, such modifications are recommended for future studies. Although the evaluation shows that the simulated stream flows are generally satisfactory, further field investigations are necessary to confirm some of the model assumptions.

  14. The History and Future of the Southern Bible Institute: A Post-Secondary School of Biblical Studies for African Americans

    Science.gov (United States)

    Cooks, Michael

    2010-01-01

    The United States of America has a long history in higher education, but one area of its history not exhausted through research involves higher education for African Americans. Specifically, higher education for African Americans in the area of theology or biblical studies presents numerous opportunities for further research. Soon after the…

  15. Distribution and pollution, toxicity and risk assessment of heavy metals in sediments from urban and rural rivers of the Pearl River delta in southern China.

    Science.gov (United States)

    Xiao, Rong; Bai, Junhong; Huang, Laibin; Zhang, Honggang; Cui, Baoshan; Liu, Xinhui

    2013-12-01

    Sediments were collected from the upper, middle and lower reaches of both urban and rural rivers in a typical urbanization zone of the Pearl River delta. Six heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) were analyzed in all sediment samples, and their spatial distribution, pollution levels, toxicity and ecological risk levels were evaluated to compare the characteristics of heavy metal pollution between the two rivers. Our results indicated that the total contents of the six metals in all samples exceeded the soil background value in Guangdong province. Based on the soil quality thresholds of the China SEPA, Cd levels at all sites exceeded class III criteria, and other metals exhibited pollution levels exceeding class II or III criteria at both river sites. According to the sediment quality guidelines of the US EPA, all samples were moderately to heavily polluted by Cr, Cu, Ni, Pb and Zn. Compared to rural river sites, urban river sites exhibited heavier pollution. Almost all sediment samples from both rivers exhibited moderate to serious toxicity to the environment, with higher contributions from Cr and Ni. A "hot area" of heavy metal pollution being observed in the upper and middle reaches of the urban river area, whereas a "hot spot" was identified at a specific site in the middle reach of the rural river. Contrary metal distribution patterns were also observed along typical sediment profiles from urban and rural rivers. However, the potential ecological risk indices of rural river sediments in this study were equal to those of urban river sediments, implying that the ecological health issues of the rivers in the undeveloped rural area should also be addressed. Sediment organic matter and grain size might be important factors influencing the distribution profiles of these heavy metals.

  16. the southern african perspective

    African Journals Online (AJOL)

    uvt

    1981-06-27

    Jun 27, 1981 ... The subject of migration falls under the ambit of regional integration and within the peace and security sphere of international law. The peace and security mandate departs from the position that it is in cultivating the spirit of good neighbourliness that peaceful neighbourhoods can be built. Subsequently, the ...

  17. Southern African Business Review

    African Journals Online (AJOL)

    Supply chain security orientation in the pharmaceutical industry · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. S. van Niekerk, W. Niemann, T. Kotzé, K. Mocke, 446-479 ...

  18. Southern African Business Review

    African Journals Online (AJOL)

    Mxit advertising's influence on cognitive attitudes amongst Millennials in the Western Cape · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. RG Duffett, 137-158 ...

  19. PENGELOLAAN SUNGAI BERBASIS MASYARAKAT LOKAL DI DAERAH LERENG SELATAN GUNUNGAPI MERAPI (River Management Based on Local Community in the Southern Slope of Marapi Volcano

    Directory of Open Access Journals (Sweden)

    Darmakusuma Darmanto

    2013-07-01

    Full Text Available ABSTRAK Dalam kehidupan manusia, ternyata ada hubungan yang saling terkait antara manusia dengan sungai. Manusia memerlukan sungai untuk mendukung keperluan dan aktivitasnya, sebaliknya keberadaan sungai juga dapat dipengaruhi oleh aktivitas manusia. Dalam memanfaatkan dan memelihara sungai tidak terlepas dari pemanfaatan air di dalam sungai dan alur sungainya. Dalam memgelola sungai tidak terpisahkan antara pengelolaan air sungai dan alur sungainya. Hal tersebut juga tergantung dari karakteristik sungai dan kondisi sosial budaya masyarakat. Penelitian yang dilakukan di lereng selatan Gunungapi Merapi dengan cara survei di lapangan. Data dikumpulkan dengan observasi lapangan dan wawancara dengan masyarakat. Selanjutnya dikuti dengan analisis data secara deskriptif kualitatif. Sungai sungai besar di daerah penelitian telah dikelola oleh pemerintah, sedangkan masyarakat lebih berperan kepada pemanfaatan dan pemeliharaan sungai kecil. Berbagai penggunaan dilakukan terhadap sungai-sungai kecil, untuk keperluan rumah tangga, irigasi dan perikanan. Teknik pengambilan dan pemanfaatan air dilakukan dengan cara sederhana dengan beaya yang relatif murah, tetapi tetap mengedepankan azas kebersamaan dan keadilan. Pemeliharaan terhadap alur sungai terhadap kerusakkan lingkungan dilakukan berdasarkan atas kesadaran untuk keberlangsungan lingkungan dengan yang dilakukan secara perorangan dan berkelompok. Dalam pemeliharaan dikedepankan asas kegotongroyongan tanpa mengabaikan budaya masyarakat setempat. ABSTRACT In human life, there was a relationship between human activities with rivers. Humans need rivers to support their need and their activities; otherwise the existence of rivers can also be affected by human activities. The management of river cannot be separated from managing water in the river and its channels. It also depends on rivers characteristics as well as social and culture of the community. This research was conducted in the southern slopes of

  20. Interannual sea level variability in the Pearl River Estuary and its response to El Niño-Southern Oscillation

    Science.gov (United States)

    Wang, Linlin; Li, Qiang; Mao, Xian-zhong; Bi, Hongsheng; Yin, Peng

    2018-03-01

    The South China coast, especially the Pearl River Estuary (PRE) region, is prosperous and densely populated, but vulnerable to sea level changes. Sea level anomalies (SLA) during 1954-2012 from tide gauge station data and regional SLAs during 1993-2012 from satellite altimetry are analyzed and compare to the El Niño-Southern Oscillation (ENSO). Results show that sea level declines during El Niño events and rises during La Niña. Sea level in the PRE responds to ENSO with 3-month lag. The ENSO can cause sea level in the PRE to fluctuate from -8.70 to 8.11 cm. Sea level cycles of 3 and 5 years are related to ENSO. The ENSO mechanism affecting sea level in the PRE was analyzed by identifying dominant regional and local forces. Weak/strong SLAs in most El Niño/La Niña events may be attributed to less/more seawater transport driven by anomalously weak/strong north winds and local anomalously high/low sea level pressure. Wind-driven coastal current is the predominant factor. It generated coastal seawater volume transport along a 160 km wide cross section to decrease by 21.07% in a typical El Niño period (January 2010) and increase by 44.03% in a typical La Niña period (January 2011) as compared to an ENSO neutral situation (January 2013). Results of sea level rise and its potential mechanism provide insight for disaster protection during extreme El Niño/La Niña events.

  1. Controls on large landslide distribution and implications for the geomorphic evolution of the southern interior Columbia River basin

    Science.gov (United States)

    Safran, E.B.; Anderson, S.W.; Mills-Novoa, M.; House, P.K.; Ely, L.

    2011-01-01

    Large landslides (>0.1 km2) are important agents of geomorphic change. While most common in rugged mountain ranges, large landslides can also be widespread in relatively low-relief (several 100 m) terrain, where their distribution has been relatively little studied. A fuller understanding of the role of large landslides in landscape evolution requires addressing this gap, since the distribution of large landslides may affect broad regions through interactions with channel processes, and since the dominant controls on landslide distribution might be expected to vary with tectonic setting. We documented >400 landslides between 0.1 and ~40 km2 across ~140,000 km2 of eastern Oregon, in the semiarid, southern interior Columbia River basin. The mapped landslides cluster in a NW-SE-trending band that is 50-100 km wide. Landslides predominantly occur where even modest local relief (~100 m) exists near key contacts between weak sedimentary or volcaniclastic rock and coherent cap rock. Fault density exerts no control on landslide distribution, while ~10% of mapped landslides cluster within 3-10 km of mapped fold axes. Landslide occurrence is curtailed to the NE by thick packages of coherent basalt and to the SW by limited local relief. Our results suggest that future mass movements will localize in areas stratigraphically preconditioned for landsliding by a geologic history of fluviolacustrine and volcaniclastic sedimentation and episodic capping by coherent lava flows. In such areas, episodic landsliding may persist for hundreds of thousands of years or more, producing valley wall slopes of ~7??-13?? and impacting local channels with an evolving array of mass movement styles. ?? 2011 Geological Society of America.

  2. Invasive alien plants and South African rivers: a proposed approach to the prioritisation of control operations

    CSIR Research Space (South Africa)

    Van Wilgen, BW

    2007-01-01

    Full Text Available es Blac k wattl e (Acaci a mearns ii D e Wild .) Riparia n zo n es o fper ennia l rivers ;upla nd s In cr ea se s to ta le v a po ra tio n a n d de cr ea se s st re a m flo w ; di sp la ce... s rip ar ia n v eg et at io n a n d de st ab ili se s riv er ba nk s V er y widesp rea d a n d abun dan t 43 2 Gre y po pla r( Pop ulu s cane scen s [Ai ton ]Sm. ) Riparia n zo n es o fper ennia...

  3. Microbial flora in organic honey samples of africanized honeybees from Parana river islands

    Directory of Open Access Journals (Sweden)

    Maria Josiane Sereia

    2011-06-01

    Full Text Available The purpose of this study was to verify and compare the main contamination sources and the hygienic/sanitary conditions of organic honey samples of Apis mellifera from Parana River islands. Thirty-three (33 samples were analyzed between January 2005 and August 2006. Eleven (11 samples were collected by beekeepers and twenty-two (22 samples were collected and processed in accordance with ideal personal hygiene norms and good manufacturing practices. The samples underwent microbiological analysis in search of coliforms at 35 ºC and 45 ºC, as well as fungi enumeration analysis. As for fungi counting, the samples harvested by beekeepers showed values above the maximum established by Resolution nº 15/94 of Common Market Group - Mercosul. The results showed that secondary contamination sources are responsible for the reduction of organic honey quality.

  4. River-Borne Sediment Exports, Sedimentation Rates, and Influence on Benthos and Leaflitter Breakdown in Southern Caribbean Mangroves (uraba, Colombia)

    Science.gov (United States)

    Blanco, J. F.; Taborda, A.; Arroyave, A.

    2011-12-01

    Deposition of river-borne sediments is a major issue in coastal ecosystems worldwide, but no study has been conducted in Neotropical mangroves. Mangroves in the Urabá Gulf (Southern Caribbean coast of Colombia) receive one of the highest sediment loads (crop district. Annual sedimentation rates were computed based in monthly samplings (2009-2010) in mangrove fringes across the Turbo River Delta using bottom-fixed 1L-cylinders (n=15). A significant spatial variation (0.04-0.9 ton m-2 yr-1) was observed among sampling stations within the delta, but the highest trapping occurred on river's main channel (2.54 ton m-2 yr-1). Temporal variation was smaller than spatial variation. Monitoring (twenty 1-m2 quadrats x 3 sites x 12 months) of a dominant mangrove-floor gastropod (Neritina virginea) observed a positive increase of density (4-125 ind. m-2: One-way ANOVA: p<0.001) along a sedimentation gradient (monthly means for low and high sedimentation sites: 3-69 kg m-2 yr-1). The role of N. virginea on leaflitter breakdown relative to sedimentation level was experimentally tested in a black mangrove (Avicennia germinans) stand by using 180 wire-mesh cages (15 x 15 x 25 cm) placed on the forest floor as experimental units, to prevent snail and crab access. After clearing existing snails and litter from the muddy bottom, each cage was placed and 1 senescent leaf of A. germinans and 7 snails were introduced (previously weighed) (snail abundance was similar to background densities). Three levels of area-weighed sedimentation rates (1, 3 and 18 g per cage) were daily added to test the impacts of the field-observed sedimentation gradient. The experiment was carried out during one month. Fresh leaf mass was different among treatments during the first week, increasing in proportion to the sedimentation rate probably due to leaf soaking. However, there was no difference in fresh leaf weight loss (average: 67%) among sediment levels after one month. Fresh weight loss (range: 81

  5. Sexual behaviors, perception of sexually transmitted infection risk, and practice of safe sex among southern African American women who have sex with women.

    Science.gov (United States)

    Muzny, Christina A; Harbison, Hanne S; Pembleton, Elizabeth S; Austin, Erika L

    2013-05-01

    Women who have sex with women (WSW) and women who have sex with women and men (WSWM) are frequently perceived to be at low risk for sexually transmitted infections (STIs), although data show that their STI rates are similar to heterosexual women. Little research has examined sexual behaviors, perceptions of STI risk, and practice of safe sex among African American WSW/WSWM living in the Southern United States, a population of women likely to be at high risk for STIs. Focus group discussions were conducted with African American WSW/WSWM living in Birmingham, Alabama, to explore their sexual behaviors with women, perceptions of STI risk from female (and male) sexual partners, and practice of safe sex. Digital audio-recordings were transcribed and analyzed using HyperRESEARCH software. Seven focus groups were conducted between August 2011 and March 2012, with 29 total participants. Women reported a broad range of sexual behaviors with female partners. They were more aware of their risk for STI acquisition from male partners than from female partners and felt that their best options for safe sex in their relationships with women were practicing good hygiene and requiring proof of STI testing results. African American WSW/WSWM in this study were aware of their STI risk, more so with regard to men, and desired accurate information on safer sex options in their sexual relationships with women. Health care providers can assist these women by helping them apply their existing knowledge of heterosexual STI transmission to their female sexual partnerships.

  6. Development of the African continent deduced from U-Pb chronology and trace element chemistry of detrital monazites from major rivers

    Science.gov (United States)

    Itano, Keita; Iizuka, Tsuyoshi; Chang, Qing; Kimura, Jun-Ichi

    2015-04-01

    To better understand the development of the African continent and, by implication, the Gondwana supercontinent, we present U-Pb age and trace element data for ca. 500 detrital monazite grains corrected from five African major rivers (the Nile, Niger, Congo, Zambezi and Orange Rivers). Monazite, a light-REE phosphate, occurs as an accessory mineral in low-Ca felsic rocks and middle- to high-grade metamorphic rocks. Because monazite has high U, Th and low common Pb contents, it is suitable for precise U-Pb chronology. In addition, its crystallization condition can be recorded by the trace element composition. Consequently, combination of U-Pb dating and trace element analysis of detrital monazites from large rivers would provide valuable insights into the timing and nature of orogeny resulting from supercontinent assembly. For this, we determined U-Pb ages and trace element compositions of the monazite grains by LA-SF-ICP-MS and LA-ICP-QMS, respectively. Detrital monazite U-Pb age distributions of all studied rivers except for the Orange River indicate prominent age peaks between 700 and 480 Ma, corresponding to the period of the Gondwana supercontinent assembly. In detail, each river shows a different age distribution and peak(s) (Nile: 580-600 Ma, Niger: 560-600 Ma, Congo: 540-560 and 600-640 Ma, Zambezi: 480-500 Ma, Orange: 900-1200 Ma). Furthermore, detrital monazite grains show variable trace element signatures, especially in [Eu/Eu*]N, [Gd/Lu]N and [Th/U]N ratios. Given that these trace element signatures reflect the effects of co-existing minerals, such as feldspar, garnet and zircon (Rubatto et al., 2006), the trace element data allow us to interpret the geologic significance of the identified age peaks. By combining the U-Pb age and the trace element data, we obtained the following picture for the development of the African continent: metamorphic events took place in the drainage basin area of the Congo River during the orogeny correlated to collision

  7. Analysis of ten year return period floods in west african rivers

    Science.gov (United States)

    Nka Nnomo, Bernadette; Oudin, Ludovic; Paturel, Jean Emmanuel; Karambiri, Harouna; Ribstein, Pierre

    2014-05-01

    In West Africa, flood and flow are usually determined by using methods advocated by the FAO (1996) and developed by ORSTOM and CIEH researchers in the 1960s. However, the 1970s, 1980s, 1990s decades were characterized by very low precipitation amounts, leading to low stream flows in river basins, except in the Sahelian region where the impact of human activities led to a substantial increase of floods in some catchments. More recently, studies pointed out an increase in the frequency of intense rainfall events and an increase of flood events. Consequently, the reliability of conventional methods for flood estimation is questionable. In this work, we analyzed the trends of the ten-year return period rainfall and stream flow events for several catchments in the Sahelian and Sudanian regions. We used eleven tributaries of large river basins (Niger, Nakambe, Senegal, Gambia) for which daily rainfall and flow data were collected from national hydrological services of four countries over West Africa (Burkina Faso, Mali, Niger, Senegal). The conjoint use of rainfall and flow data allowed us to analyze the possible causality link between the two variables. Mann-Kendall, Pettitt and Hubert tests were used to detect trends and abrupt change points in the annual maximum time series.The quantification of change was assessed by computing 10-year return period rain and flow values on sliding sub periods in the long-term maxima time series with the GEV distribution. Trend tests on annual maximum flows time series showed mixed results depending on the location of the catchments: generally speaking, a decrease is observed for Sudanian catchments and an increase is observed for Sahelian catchments. On a period of 50 years (1950 - 2010) we pointed out an increase of 72% of the mean value of flood 10-year return period for a station like Kakassi in the sahelian region, with respect to the period before the detected disruption; while for a soudanian catchment like Fadougou, the average

  8. Trace element enrichment in off-craton peridotites: comparison of off-craton Proterozoic and Pan-African mantle beneath southern Africa

    Science.gov (United States)

    le Roex, Anton; Class, Cornelia

    2014-05-01

    Trace element abundances in constituent clinopyroxene, garnet and phlogopite from off-craton mantle beneath the Proterozoic Namaqua-Natal belt (South Africa) and in clinopyroxene and amphibole from the Pan African Damara belt (Namibia) have been determined by laser ablation ICP-MS. Chondrite normalised rare earth element abundances in clinopyroxenes show a wide range of patterns from LREE depleted, through sinusoidal patterns to strongly LREE enriched. In garnets, the patterns range from strongly LREE depleted with flat HREE, through sinusoidal patterns to 'humped' sinusoidal patterns. Numerical modelling shows that the range of REE enrichment patterns can be generated via reactive porous flow mechanisms involving an alkaline silicate melt and where, in the Proterozoic mantle, there is a high fluid/solid ratio (i.e. all clinopyroxene and garnet are products of modal metasomatism and/or near fully equilibrated with a metasomatic fluid). In contrast, clinopyroxene in the Pan African mantle shows evidence for cryptic metasomatism, where enrichment of pre-existing clinopyroxene by alkaline silicate melts has occurred at the distal regions of an advancing metasomatic front. Extreme fluid/melt compositions are not required to account for the enrichment patterns Numerical modelling of primitive mantle normalised trace element abundances in clinopyroxenes show that the commonly observed strong relative depletions in Nb-Ta and Rb-Ba present in clinopyroxenes can be accounted for by crystallisation of accessory phlogopite (in Proterozoic mantle) and amphibole (in Pan African mantle) from the metasomatising melt/fluid. In contrast, strong relative depletion in Zr-Hf in some clinopyroxenes in both Proterozoic and Pan African mantle regions requires either metasomatic crystallisation of zircon, or involvement of a carbonatitic melt as metasomatic agent. Trace element enrichment patterns seen in clinopyroxene and garnet in the Proterozoic off-craton regions of southern Africa

  9. Study on Freshwater Macroinvertebrates of Some Tanzanian Rivers as a Basis for Developing Biomonitoring Index for Assessing Pollution in Tropical African Regions

    Directory of Open Access Journals (Sweden)

    Julius D. Elias

    2014-01-01

    Full Text Available Macroinvertebrates and physicochemical parameters were assessed at 15 sites along five rivers in Kilimanjaro region, Tanzania, with the aim of understanding their ecological status and setting a base to the development of a biological index for tropical regions. Investigated rivers that occur within Pangani basin include Karanga, Rau, Lumbanga, Sere, and Umbwe. Sampling sites were categorized according to the level of water and habitat quality as follows: reference or least impacted (4 sites, moderately impacted (5 sites, and highly impacted (6 sites sites. A total of 12,527 macroinvertebrates belonging to 13 orders and 48 families were recorded. The highest total abundance of 4,110 individuals per m2 was found in Karanga river, while Umbwe river had the lowest with 1,203 individuals per m2. Chironomidae was the most abundant family (2,588 individuals per m2 and the least were Hydridae and Thiaridae, each having 5 individuals per m2. High numbers of taxa were noted among the orders: Ephemeroptera (8, Odonata (8, Diptera (7, and Trichoptera (6. In conclusion, orders with greater diversity of macroinvertebrate families offer a wide range of tolerance to pollution and, thus can potentially be used to develop a biomonitoring index for evaluating pollution in tropical African rivers.

  10. Hematological and histopathological changes in silver catfish Rhamdia quelen (Siluriformes) exposed to clomazone herbicide in the Madre River, Santa Catarina State, Southern Brazil.

    Science.gov (United States)

    Brum, Aline; Dotta, Geovana; Roumbedakis, Katina; Gonçalves, Eduardo L T; Garcia, Laura P; Garcia, Patrícia; Scussel, Vildes M; Martins, Maurício L

    2014-01-01

    This study evaluated the influence of the clomazone herbicide (2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone) contamination on the hematological parameters and histological changes in gills and liver of silver catfish (Rhamdia quelen) from Madre River, Santa Catarina State, Southern Brazil. Fish were collected between March 2010 and January 2012 at two different sites of the Madre River, one site receiving residual water (contaminated site) from rice culture (n=49) and another that do not receive residual water (reference site) (n=48). The herbicide clomazone analysis detected 3.40±1.70 μg/L in the contaminated site and 1.1±0.33 μg/L in the reference site. Fish from contaminated site showed increased (PFish from both sites showed histopathological changes in gills and liver, possibly caused by chronic exposure to contamination. The influence of herbicide sub doses on fish health is also discussed.

  11. Some results of long-term investigation population exposed as a result of release of radioactive wastes into the Techa River in Southern Urals

    Energy Technology Data Exchange (ETDEWEB)

    Degteva, M.O.; Kozheurov, V.P.; Vorobiova, M.I. [Ural research Center for Radiation Medicine, Chelyabinsk (Russian Federation)

    1992-06-01

    This paper describes results of a long-term investigation of a population exposed to radioactive waste release in 1949-1956 into the Techa River in the Southern Urals. Systematic measurements of radionuclide concentration in the river waters, sediments, and floodplain soils and measurements of exposure gamma dose rates as well as studies of the radionuclide composition in the contaminated areas began in the summer of 1951. As a result of the contamination, 124,000 residents were exposed to radiation and 28,100 received significant doses in terms of health effect potential. Covered results include the following: estimation of external radiation doses; content of strontium-90 in humans and estimation of radionuclide ingestion rates; age-dependent model of strontium metabolism in the human body; evaluation of doses of internal irradiation; distribution of exposed population according to accumulated doses. 11 refs; 15 figs.

  12. The Effect of China’s Scramble for Resources and African Resource Nationalism on the Supply of Strategic Southern African Minerals: What Can the United States Do?

    Science.gov (United States)

    2010-01-01

    be wholesale; some mines may be nationalized, and some will not. The South African government is looking at Brazil as a model for increasing tax...Korea, Malaysia, Brazil , Russia, Kazakhstan and other countries are also seeking minerals. For relevant news stories, see Africa-Asia Confidential. 7...sodimico- sale,95130790-BRE. 38 “Congo’s outback : Mr. Copper,” The Economist, August 20, 2011. 39 Elizabeth Jaffee, US Embassy, Kinshasa, briefing

  13. Evaluation of the distribution of fecal indicator bacteria in a river system depending on different types of land use in the southern watershed of the Baltic Sea.

    Science.gov (United States)

    Gotkowska-Płachta, Anna; Gołaś, Iwona; Korzeniewska, Ewa; Koc, Józef; Rochwerger, Andrzej; Solarski, Kamil

    2016-03-01

    The aim of the study was to determine the effects of land use management on changes in the fecal contamination of water in the Łyna River, one of the main lowland watercourses in the southern watershed of the Baltic Sea (northern Poland). A total of 120 water samples were collected in different seasons of 2011 and 2012 at 15 sites where the river intersected forest (FA), agricultural (AA), and urbanized (UA) areas. Fecal indicator bacteria (FIB), the counts of Enterobacteriaceae and Escherichia coli, total bacterial counts (TBCs), and domain Bacteria (EUB338) were determined by culture-dependent and culture-independent methods. Temperature, pH, chemical oxygen demand, dissolved oxygen, total dissolved solids, ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, orthophosphate, and total phosphorus were also determined. The lowest bacterial counts were noted in water samples collected in FA, and the highest in samples collected in UA. Statistically significant differences were determined between bacterial populations across the analyzed land use types and in different sampling seasons. Significant correlations were also observed between the populations of FIB and physicochemical parameters. The results indicate that land use type influenced FIB concentrations in river water. The combined use of conventional and molecular methods improves the accuracy of fecal contamination analyses in river ecosystems.

  14. Sediment Budget Analysis and Hazard Assessment in the Peynin, a Small Alpine Catchment (Upper Guil River, Southern Alps, France)

    Science.gov (United States)

    Carlier, Benoit; Arnaud-Fassetta, Gilles; Fort, Monique; Bouccara, Fanny; Sourdot, Grégoire; Tassel, Adrien; Lissak, Candide; Betard, François; Cossart, Etienne; Madelin, Malika; Viel, Vincent; Charnay, Bérengère; Bletterie, Xavier

    2014-05-01

    The upper Guil catchment (Southern Alps) is prone to hydro-geomorphic hazards. Major hazards are related to catastrophic floods, with an amplification of their impacts due to strong hillslope-channel connectivity as observed in 1957 and 2000. In both cases, the rainfall intensity, aggravated by the pre-existing saturated soils, explained the instantaneous response of the fluvial system, such as destabilisation of slopes, high sediment discharge, and subsequent damages to exposed structures and settlements present in the floodplain and at confluence sites. The Peynin junction with the Guil River is one of these sites, where significant land-use change during the last decades in relation to the development of handicraft and tourism economy has increased debris flow threat to population. Here, we adopt a sediment budget analysis aimed at better understanding the functioning of this small subcatchment. This latter offers a combination of factors that favour torrential and gravitational activity. It receives abundant and intense rainfall during "Lombarde" events (moist air mass from Mediterranean Sea). Its elongated shape and small surface area (15 km²) together with asymmetric slopes (counter dip slope on the left bank) accelerate runoff on a short response time. In addition highly tectonised shaly schists supply a large volume of debris (mostly platy clasts and fine, micaceous sediment). The objectives of this study, carried out in the frame of SAMCO (ANR) project, are threefold: Identify the different sediment storages; Characterise the processes that put sediment into motion; Quantify volumes of sediment storages. We produced a geomorphic map using topographic surveys and aerial photos in order to locate the different sediment storage types and associated processes. This analysis was made with respect to geomorphic coupling and sediment flux activity. In terms of surface area, the dominant landforms in the valley were found to be mass wasting, talus slopes and

  15. Hydro-Geological Hazard Temporal Evolution during the last seven decades in the Solofrana River Basin—Southern Italy

    Science.gov (United States)

    Longobardi, Antonia; Diodato, Nazzareno; Mobilia, Mirka

    2017-04-01

    Extremes precipitation events are frequently associated to natural disasters falling within the broad spectrum of multiple damaging hydrological events (MDHEs), defined as the simultaneously triggering of different types of phenomena, such as landslides and floods. The power of the rainfall (duration, magnitude, intensity), named storm erosivity, is an important environmental indicator of multiple damaging hydrological phenomena. At the global scale, research interest is actually devoted to the investigation of non-stationary features of extreme events, and consequently of MDHEs, which appear to be increasing in frequency and severity. The Mediterranean basin appears among the most vulnerable regions with an expected increase in occurring damages of about 100% by the end of the century. A high concentration of high magnitude and short duration rainfall events are, in fact, responsible for the largest rainfall erosivity and erosivity density values within Europe. The aim of the reported work is to investigate the relationship between the temporal evolution of severe geomorphological events and combined precipitation indices as a tool to improve understanding the hydro-geological hazard at the catchment scale. The case study is the Solofrana river basin, Southern Italy, which has been seriously and consistently in time affected by natural disasters. Data for about 45 MDH events, spanning on a decadal scale 1951-2014, have been collected and analyzed for this purpose. A preliminary monthly scale analysis of event occurrences highlights a pronounced seasonal characterization of the phenomenon, as about 60% of the total number of reported events take place during the period from September to November. Following, a statistical analysis clearly indicates a significant increase in the frequency of occurrences of MDHEs during the last decades. Such an increase appears to be related to non-stationary features of an average catchment scale rainfall-runoff erosivity index

  16. Fine-scale fault structures revealed by earthquake relocations near the Leech River Fault, southern Vancouver Island

    Science.gov (United States)

    Li, G.; Liu, Y.; Regalla, C.; Morell, K. D.

    2016-12-01

    We present results of microseismic relocations that delineate potentially seismogenic structures along the Leech River Fault (LRF), southern Vancouver Island. The potential seismic activity of the LRF in particular has been the focus of many recent investigations, given its proximity to Victoria, the capitol of British Columbia. We investigate the seismic evidence of subsurface structures near the LRF by relocating 1528 earthquakes reported by Canadian National Seismograph Network (CNSN) catalog from 1985 to 2015 using the HypoDD [Waldhauser, F., 2001] method. This relocation procedure reveals two general northeast dipping structures representing the subsurface fractured deformation zone beneath the LRF and the San Juan Islands area, respectively. The subsurface structure underlying the LRF extends about 30 km along the LRF strike and has a dip of about 45o, which is generally consistent with fault dip inferred from seismic imaging [Green et al., 1987]. In addition, we use the k-mean++ clustering algorithm [Lloyd, 1982; Arthur et al., 2007] to select 5-subclusters for individual relocations in order to investigate possible finer faulting structures. The relocated sub-cluster seismicity, combined with earthquake focal mechanism solutions from previous studies, delineates the subsurface geometry of minor faults near the LRF. Relocation results also show the eastern segment is seismically active while the western segment lacks seismicity. We suggest two potential explanations for this marked variation in seismic behavior. First, seismicity might reflect variations in the regionals tress field [Balfour et al., 2011]. The orientation of the maximum horizontal compressive stress near the LRF is 10-30° clockwise from the strike of eastern segment, which would promote right lateral slip, but is nearly orthogonal to the strike of the western segment, which would inhibit slip. Second, foliations and mylonitic fabric are generally stronger, more developed, and exist over a

  17. Occurrence of Arsenic in Soils and Paleosols of the Claromecó River Basin, Southern Pampean Plain (Argentina)

    Science.gov (United States)

    Sosa, N. N.; Datta, S.; Zarate, M.; Porfido, C.; Spagnuolo, M.; Terzano, R.

    2016-12-01

    The Chacopampean plain is an extended flatland characterized by high As within sediments and drinking waters. The volcanic glass shards, normally present as a major constituent of the Chacopampean plain sediments, are classically considered the main source of As. Nevertheless, thick volcanic ash layers and Fe-Mn (Al) oxy-hydroxides are also contemplated as a reasonable source of As. In order to understand the main source of As in the Claromecó river basin (southern Chacopampean plain) sediments, paleosols, present-day soils and groundwaters were sampled. Three sedimentological units were identified: a deeper early Pliocene fluvial unit (mean sediment As 4.6 mg/kg), a shallower late Pleistocene fluvial unit (mean As 11.6mg/kg) and Holocene Loess (mean As 2.5 mg/kg). Two types of paleosols were characterized: a Pliocene pedogenic calcrete (mean As 3.6 mg/kg) and a Late Pleistocene hydromorphic paleosol (mean As 16.5 mg/kg). The present-day soils were taken into account where mean As is 10.5 mg/kg. Although mean values for each unit are quite different, statistical analyses (ANOVA) reveal no statistically significant difference between As concentrations within the various sedimentological units. However, the hydromorphic paleosols and present day soils show a statistically significant difference from the rest of the units. In these pedogenetic units, the highest As concentrations are located in the Fe-Mn(Al) oxy-hydroxide phases (nodules and rhizo-concretions) as shown by sequential extractions and µ-XRF analysis. From this context, Pliocene pedogenic calcrete shows low content of oxy-hydroxides and therefore low As. Additionally, As concentrations in waters (mean As 78.42 µg/L) shows higher values in shallower groundwaters coinciding with Pleistocene paleosols. This preliminary study highlights that the sediment deposition may not necessarily represent a systematic control in the As concentrations even though an increment from the Pliocene to the Holocene in

  18. African Journals Online (AJOL)

    African Journals Online (AJOL)

    African Journals OnLine (AJOL) is the world's largest and pre-eminent collection of peer-reviewed, African-published scholarly journals. Historically, scholarly information has flowed ... international competitiveness of countries? Southern African Business Review; Conflicts in Africa: Meaning, Causes, Impact and Solution

  19. African Journals Online (AJOL)

    African Journals Online (AJOL)

    African Journals OnLine (AJOL) is the world's largest and pre-eminent collection ... Gender and climate change-induced conflict in pastoral communities: Case study of Turkana in northwestern Kenya African Journal on Conflict Resolution; Project Work by Students for First Degree: ... Southern African Journal of Critical Care.

  20. African Journals Online (AJOL)

    African Journals Online (AJOL)

    African Journals OnLine (AJOL) is the world's largest and pre-eminent collection of peer-reviewed, African-published scholarly journals. Historically ... Southern African Business Review; The Basis of Distinction Between Qualitative and Quantitative Research in Social Science: Reflection on Ontological, Epistemological and ...

  1. Rapid assessment and mapping of tree cover in southern African savanna woodlands using a new iPhone App and Landsat 8 imagery

    Science.gov (United States)

    Fuller, D. O.

    2016-12-01

    Tree cover is a key parameter in climate modeling. It strongly influences CO2 exchanges between the land surface and atmosphere and surface energy balance. We measured percent woody canopy cover (PWCC) in the savanna woodlands of eastern Zambia over a 10-day period in May 2016 using a new iPhone App (CanopyApp) and related these field measurements to Landsat 8 (L8) Band 4 (red) imagery acquired approximately the same time. We then used parameters from the band 4 digital numbers (DNs)-PWCC linear regression to derive a new map of PWCC for the entire L8 scene. Consistent with theory and previous empirical studies, we found that the relationship between L8 band 4 DNs- PWCC was negative and linear (r2 = 0.61, p sufficient to estimate PWCC when spectral contrast exists between the grass, soil and tree layers during the austral fall period in southern African savannas.

  2. Focus on CSIR research in pollution waste: South African national spatial biodiversity assessment 2004 (Technical report volume 2: river component)

    CSIR Research Space (South Africa)

    Roux, D

    2007-08-01

    Full Text Available This report forms the river component of the National Spatial Biodiversity Assessment, which focuses on spatial conservation assessments for South Africa’s terrestrial, river, marine, estuarine and wetland ecosystems. The results presented form...

  3. The African Crane Database (1978-2014): Records of three threatened crane species (Family: Gruidae) from southern and eastern Africa.

    Science.gov (United States)

    Smith, Tanya; Page-Nicholson, Samantha; Morrison, Kerryn; Gibbons, Bradley; Jones, M Genevieve W; van Niekerk, Mark; Botha, Bronwyn; Oliver, Kirsten; McCann, Kevin; Roxburgh, Lizanne

    2016-01-01

    The International Crane Foundation (ICF) / Endangered Wildlife Trust's (EWT) African Crane Conservation Programme has recorded 26 403 crane sightings in its database from 1978 to 2014. This sightings collection is currently ongoing and records are continuously added to the database by the EWT field staff, ICF/EWT Partnership staff, various partner organizations and private individuals. The dataset has two peak collection periods: 1994-1996 and 2008-2012. The dataset collection spans five African countries: Kenya, Rwanda, South Africa, Uganda and Zambia; 98% of the data were collected in South Africa. Georeferencing of the dataset was verified before publication of the data. The dataset contains data on three African crane species: Blue Crane Anthropoides paradiseus, Grey Crowned Crane Balearica regulorum and Wattled Crane Bugeranus carunculatus. The Blue and Wattled Cranes are classified by the IUCN Red List of Threatened Species as Vulnerable and the Grey Crowned Crane as Endangered. This is the single most comprehensive dataset published on African Crane species that adds new information about the distribution of these three threatened species. We hope this will further aid conservation authorities to monitor and protect these species. The dataset continues to grow and especially to expand in geographic coverage into new countries in Africa and new sites within countries. The dataset can be freely accessed through the Global Biodiversity Information Facility data portal.

  4. Designing an Effective Sexuality Education Curriculum for Schools: Lessons Gleaned from the South(ern) African Literature

    Science.gov (United States)

    Wood, Lesley; Rolleri, Lori A.

    2014-01-01

    Sexuality education forms part of the national school curricula of most sub-Saharan African countries, yet risk-related sexual behaviour among young people continues to fuel the HIV pandemic in this part of the world. One of the arguments put forward to explain why sexuality education seems to have had little impact on sexual risk-taking is that…

  5. El Niño-Southern Oscillation and water resources in the headwaters region of the Yellow River: links and potential for forecasting

    Directory of Open Access Journals (Sweden)

    A. Lü

    2011-04-01

    Full Text Available This research explores the rainfall-El Niño-Southern Oscillation (ENSO and runoff-ENSO relationships and examines the potential for water resource forecasting using these relationships. The Southern Oscillation Index (SOI, Niño1.2, Niño3, Niño4, and Niño3.4 were selected as ENSO indicators for cross-correlation analyses of precipitation and runoff. There was a significant correlation (95% confidence level between precipitation and ENSO indicators during three periods: January, March, and from September to November. In addition, monthly streamflow and monthly ENSO indictors were significantly correlated during three periods: from January to March, June, and from October to December (OND, with lag periods between one and twelve months. Because ENSO events can be accurately predicted one to two years in advance using physical modeling of the coupled ocean-atmosphere system, the lead time for forecasting runoff using ENSO indicators in the Headwaters Region of the Yellow River could extend from one to 36 months. Therefore, ENSO may have potential as a powerful forecasting tool for water resources in the headwater regions of Yellow River.

  6. Southern African guidelines on the safe use of pre-exposure prophylaxis in persons at risk of acquiring HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Linda-Gail Bekker

    2016-03-01

    Full Text Available The Southern African HIV Clinicians Society published its first set of oral pre-exposure prophylaxis (PrEP guidelines in June 2012 for men who have sex with men (MSM who are at risk of HIV infection. With the flurry of data that has been generated in PrEP clinical research since the first guideline, it became evident that there was a need to revise and expand the PrEP guidelines with new evidence of safety and efficacy of PrEP in several populations, including MSM, transgender persons, heterosexual men and women, HIV-serodiscordant couples and people who inject drugs. This need is particularly relevant following the World Health Organization (WHO Consolidated Treatment Guidelines released in September 2015. These guidelines advise that PrEP is a highly effective, safe, biomedical option for HIV prevention that can be incorporated with other combination prevention strategies in Southern Africa, given the high prevalence of HIV in the region. PrEP should be tailored to populations at highest risk of HIV acquisition, whilst further data from studies in the region accrue to guide optimal deployment to realise the greatest impact regionally. PrEP may be used intermittently during periods of perceived HIV acquisition risk, rather than continually and lifelong, as is the case with antiretroviral treatment. Recognition and accurate measurement of potential risk in individuals and populations also warrants discussion, but are not extensively covered in these guidelines.

  7. Southern African guidelines on the safe use of pre-exposure prophylaxis in persons at risk of acquiring HIV-1 infection

    Directory of Open Access Journals (Sweden)

    Linda-Gail Bekker

    2016-02-01

    Full Text Available The Southern African HIV Clinicians Society published its first set of oral pre-exposure prophylaxis (PrEP guidelines in June 2012 for men who have sex with men (MSM who are at risk of HIV infection. With the flurry of data that has been generated in PrEP clinical research since the first guideline, it became evident that there was a need to revise and expand the PrEP guidelines with new evidence of safety and efficacy of PrEP in several populations, including MSM, transgender persons, heterosexual men and women, HIV-serodiscordant couples and people who inject drugs. This need is particularly relevant following the World Health Organization (WHO Consolidated Treatment Guidelines released in September 2015. These guidelines advise that PrEP is a highly effective, safe, biomedical option for HIV prevention that can be incorporated with other combination prevention strategies in Southern Africa, given the high prevalence of HIV in the region. PrEP should be tailored to populations at highest risk of HIV acquisition, whilst further data from studies in the region accrue to guide optimal deployment to realise the greatest impact regionally. PrEP may be used intermittently during periods of perceived HIV acquisition risk, rather than continually and lifelong, as is the case with antiretroviral treatment. Recognition and accurate measurement of potential risk in individuals and populations also warrants discussion, but are not extensively covered in these guidelines.

  8. Determinants of Persistence and Tolerance of Carnivores on Namibian Ranches: Implications for Conservation on Southern African Private Lands

    NARCIS (Netherlands)

    Lindsey, P.A.; Havemann, C.P.; Lines, R.M.; Palazy, L.; Price, A.E.; Retief, T.A.; Rhebergen, T.; Waal, van der C.

    2013-01-01

    Changing land use patterns in southern Africa have potential to dramatically alter the prospects for carnivore conservation. Understanding these influences is essential for conservation planning. We interviewed 250 ranchers in Namibia to assess human tolerance towards and the distribution of large

  9. The Usumacinta-Grijalva beach-ridge plain in southern Mexico: a high-resolution archive of river discharge and precipitation

    Science.gov (United States)

    Nooren, Kees; Hoek, Wim Z.; Winkels, Tim; Huizinga, Annika; Van der Plicht, Hans; Van Dam, Remke L.; Van Heteren, Sytze; Van Bergen, Manfred J.; Prins, Maarten A.; Reimann, Tony; Wallinga, Jakob; Cohen, Kim M.; Minderhoud, Philip; Middelkoop, Hans

    2017-09-01

    The beach-ridge sequence of the Usumacinta-Grijalva delta borders a 300 km long section of the southern Gulf of Mexico coast. With around 500 beach ridges formed in the last 6500 years, the sequence is unsurpassed in the world in terms of numbers of individual ridges preserved, continuity of the record, and temporal resolution. We mapped and dated the most extensively accreted part of the sequence, linking six phases of accretion to river mouth reconfigurations and constraining their ages with 14C and OSL dating. The geomorphological and sedimentological reconstruction relied on lidar data, coring transects, GPR measurements, grain-size analyses, and chemical fingerprinting of volcanic glass and pumice encountered within the beach and dune deposits. We demonstrate that the beach-ridge complex was formed under ample long-term fluvial sediment supply and shorter-term wave- and aeolian-modulated sediment reworking. The abundance of fluvially supplied sand is explained by the presence of easily weatherable Los Chocoyos ignimbrites from the ca. 84 ka eruption of the Atitlán volcano (Guatemala) in the catchment of the Usumacinta River. Autocyclic processes seem responsible for the formation of ridge-swale couplets. Fluctuations in their periodicity (ranging from 6-19 years) are governed by progradation rate, and are therefore not indicative of sea level fluctuations or variability in storm activity. The fine sandy beach ridges are mainly swash built. Ridge elevation, however, is strongly influenced by aeolian accretion during the time the ridge is located next to the beach. Beach-ridge elevation is negatively correlated with progradation rate, which we relate to the variability in sediment supply to the coastal zone, reflecting decadal-scale precipitation changes within the river catchment. In the southern Mexican delta plain, the coastal beach ridges therefore appear to be excellent recorders of hinterland precipitation.

  10. The Usumacinta–Grijalva beach-ridge plain in southern Mexico: a high-resolution archive of river discharge and precipitation

    Directory of Open Access Journals (Sweden)

    K. Nooren

    2017-09-01

    Full Text Available The beach-ridge sequence of the Usumacinta–Grijalva delta borders a 300 km long section of the southern Gulf of Mexico coast. With around 500 beach ridges formed in the last 6500 years, the sequence is unsurpassed in the world in terms of numbers of individual ridges preserved, continuity of the record, and temporal resolution. We mapped and dated the most extensively accreted part of the sequence, linking six phases of accretion to river mouth reconfigurations and constraining their ages with 14C and OSL dating. The geomorphological and sedimentological reconstruction relied on lidar data, coring transects, GPR measurements, grain-size analyses, and chemical fingerprinting of volcanic glass and pumice encountered within the beach and dune deposits. We demonstrate that the beach-ridge complex was formed under ample long-term fluvial sediment supply and shorter-term wave- and aeolian-modulated sediment reworking. The abundance of fluvially supplied sand is explained by the presence of easily weatherable Los Chocoyos ignimbrites from the ca. 84 ka eruption of the Atitlán volcano (Guatemala in the catchment of the Usumacinta River. Autocyclic processes seem responsible for the formation of ridge–swale couplets. Fluctuations in their periodicity (ranging from 6–19 years are governed by progradation rate, and are therefore not indicative of sea level fluctuations or variability in storm activity. The fine sandy beach ridges are mainly swash built. Ridge elevation, however, is strongly influenced by aeolian accretion during the time the ridge is located next to the beach. Beach-ridge elevation is negatively correlated with progradation rate, which we relate to the variability in sediment supply to the coastal zone, reflecting decadal-scale precipitation changes within the river catchment. In the southern Mexican delta plain, the coastal beach ridges therefore appear to be excellent recorders of hinterland precipitation.

  11. Impact of wastewater on fish health: a case study at the Neckar River (Southern Germany) using biomarkers in caged brown trout as assessment tools.

    Science.gov (United States)

    Vincze, Krisztina; Scheil, Volker; Kuch, Bertram; Köhler, Heinz R; Triebskorn, Rita

    2015-08-01

    The present work describes a field survey aiming at assessing the impact of a sewage treatment plant (STP) effluent on fish health by means of biomarkers. Indigenous fish were absent downstream of the STP. To elucidate the reason behind this, brown trout (Salmo trutta f. fario) were exposed in floating steel cages up- and downstream of a STP located at the Neckar River near Tübingen (Southern Germany), for 10 and 30 days. A combination of biomarker methods (histopathological investigations, analysis of the stress protein Hsp70, micronucleus test, B-esterase assays) offered the possibility to investigate endocrine, geno-, proteo- and neurotoxic effects in fish organs. Biological results were complemented with chemical analyses on 20 accumulative substances in fish tissue. Even after short-term exposure, biomarkers revealed clear evidence of water contamination at both Neckar River sites; however, physiological responses of caged brown trout were more severe downstream of the STP. According to this, similar bioaccumulation levels (low μg/kg range) of DDE and 12 polycyclic aromatic hydrocarbons (PAHs) were detected at both sampling sites, while up to fourfold higher concentrations of four PAHs, methyl-triclosan and two synthetic musks occurred in the tissues of downstream-exposed fish. The results obtained in this study suggest a constitutive background pollution at both sites investigated at the Neckar River and provided evidence for the additional negative impact of the STP Tübingen on water quality and the health condition of fish.

  12. Tropical systems from the southwest Indian Ocean making landfall over the Limpopo River Basin, southern Africa: a historical perspective

    CSIR Research Space (South Africa)

    Malherbe, J

    2011-03-01

    Full Text Available The study provides perspective on the contribution of landfalling tropical systems (cyclones, depressions, storms and lows) from the southwest Indian Ocean (SWIO) towards rainfall over the eastern interior of southern Africa, over the period 1948...

  13. Racial comparison of receptor-defined breast cancer in Southern African women: subtype prevalence and age-incidence analysis of nationwide cancer registry data.

    Science.gov (United States)

    Dickens, Caroline; Duarte, Raquel; Zietsman, Annelle; Cubasch, Herbert; Kellett, Patricia; Schüz, Joachim; Kielkowski, Danuta; McCormack, Valerie

    2014-11-01

    Receptor-defined breast cancer proportions vary across Africa. They have important implications for survival prospects and research priorities. We studied estrogen receptor (ER), progesterone receptor (PR), and HER2 receptor statuses in two multiracial Southern African countries with routine diagnostic immunohistochemistry. A total of 12,361 women with histologically confirmed breast cancer diagnosed at age ≥20 years during (i) 2009-2011 from South Africa's national cancer registry (public sector) and (ii) 2011-2013 from Namibia's only cancer hospital were included. Crude, age, and age + laboratory-adjusted ORs of receptor status were analyzed using logistic regression, and age-incidence curves were analyzed using Poisson regression. A total of 10,047 (81%) women had known ER status. Ranking of subtypes was consistent across races: ER(+)/PR(+)HER2(-) was most common (race-specific percentage range, 54.6%-64.8%), followed by triple-negative (17.4%-21.9%), ER(+)/PR(+)HER2(+) (9.6%-13.9%), and ER(-)PR(-)HER2(+) (7.8%-10.9%). Percentages in black versus white women were 33.8% [95% confidence (CI), 32.5-35.0] versus 26.0% (24.0-27.9) ER(-); 20.9% (19.7-22.1) versus 17.5% (15.4-19.6) triple-negative; and 10.7% (9.8-11.6) versus 7.8% (6.3-9.3) ER(-)PR(-)HER2(+). Indian/Asian and mixed-ancestry women had intermediate values. Age-incidence curves had similar shapes across races: rates increased by 12.7% per year (12.2-13.1) across ER subtypes under the age of 50 years, and thereafter slowed for ER(+) (1.95%) and plateaued for ER(-) disease (-0.1%). ER(+) breast cancer dominates in all Southern African races, but black women have a modest excess of aggressive subtypes. On the basis of the predominant receptor-defined breast tumors in Southern Africa, improving survival for the growing breast cancer burden should be achievable through earlier diagnosis and appropriate treatment. ©2014 American Association for Cancer Research.

  14. Where to Target Conservation Agriculture for African Smallholders? How to Overcome Challenges Associated with its Implementation? Experience from Eastern and Southern Africa

    Directory of Open Access Journals (Sweden)

    Frédéric Baudron

    2015-07-01

    Full Text Available Since the paper by Giller et al. (2009, the debate surrounding the suitability of conservation agriculture (CA for African smallholders has remained polarized between proponents and opponents. The debate also gave rise to a few studies that attempted to identify the “niche” where CA would fit in the region, but the insight offered by these studies has been limited. In this paper, we first analyze the rationale of adoption where it occurred globally to define “drivers” of adoption. Our analysis suggests that CA has first and foremost been adopted under the premises of being energy-saving (time and/or power, erosion-controlling, and water-use efficient, but rarely to increase yield. We then define the niche where CA fits, based on these drivers of adoption, as systems where (1 the energy available for crop establishment is limited and/or costly (including labor and draft power; (2 delayed planting results in a significant yield decline; (3 yield is limited or co-limited by water; and/or (4 severe erosion problems threaten the short- to medium-term productivity of farmland. In Eastern and Southern Africa, this niche appears rather large and likely to expand in the near future. When implemented within this niche, CA may still be limited by “performance challenges” that do not constitute drivers or barriers to adoption, but limitations to the performance of CA. We argue that most of these performance challenges can (and should be addressed by agronomic and socio-economic research, and provide four examples where the International Maize and Wheat Improvement Center (CIMMYT and its partners have been successfully alleviating four very different challenges through research and development (R&D in Eastern and Southern Africa. Finally, we describe an iterative and multi-scale R&D approach currently used by CIMMYT in Eastern and Southern Africa to overcome challenges associated with the implementation of CA by African smallholders. This

  15. Spatio-Temporal Analysis of Vegetation Dynamics in Relation to Shifting Inundation and Fire Regimes: Disentangling Environmental Variability from Land Management Decisions in a Southern African Transboundary Watershed

    Directory of Open Access Journals (Sweden)

    Narcisa G. Pricope

    2015-07-01

    Full Text Available Increasing temperatures and wildfire incidence and decreasing precipitation and river runoff in southern Africa are predicted to have a variety of impacts on the ecology, structure, and function of semi-arid savannas, which provide innumerable livelihood resources for millions of people. This paper builds on previous research that documents change in inundation and fire regimes in the Chobe River Basin (CRB in Namibia and Botswana and proposes to demonstrate a methodology that can be applied to disentangle the effect of environmental variability from land management decisions on changing and ecologically sensitive savanna ecosystems in transboundary contexts. We characterized the temporal dynamics (1985–2010 of vegetation productivity for the CRB using proxies of vegetation productivity and examine the relative importance of shifts in flooding and fire patterns to vegetation dynamics and effects of the association of phases of the El Niño—Southern Oscillation (ENSO on vegetation greenness. Our results indicate that vegetation in these semi-arid environments is highly responsive to climatic fluctuations and the long-term trend is one of increased but heterogeneous vegetation cover. The increased cover and heterogeneity during the growing season is especially noted in communally-managed areas of Botswana where long-term fire suppression has been instituted, in contrast to communal areas in Namibia where heterogeneity in vegetation cover is mostly increasing primarily outside of the growing season and may correspond to mosaic early dry season burns. Observed patterns of increased vegetation productivity and heterogeneity may relate to more frequent and intense burning and higher spatial variability in surface water availability from both precipitation and regional inundation patterns, with implications for global environmental change and adaptation in subsistence-based communities.

  16. River

    Directory of Open Access Journals (Sweden)

    Morel Mathieu

    2016-01-01

    Full Text Available The OECD report “Boosting Resilience through Innovative Risk Governance” examines the efforts of OECD countries to prevent or reduce future disaster impacts, and highlights several key areas where improvements can be made. International collaboration is insufficiently utilised to address shocks that have increasingly global consequences. Institutional design plays a significant role in facilitating or hampering the engagement and investments of governmental and non-governmental stakeholders in disaster risk prevention and mitigation. To inform the design of “better” institutions, the OECD proposes the application of a diagnostic framework that helps governments identify institutional shortcomings and take actions to improve them. The goal of the case study on the Rhone River is to conduct an analysis of the progress, achievements and existing challenges in designing and implementing disaster risk reduction strategies through the Rhone Plan from a comparative perspective across a set of selected countries of this study, like Austria and Switzerland, will inform how to improve institutional frameworks governing risk prevention and mitigation. The case study will be used to identify examples of successful practice taking into account their specific country contexts, and analyse their potential for policy transfer.

  17. The role of teacher values in the mediation of ESL innovation programmes: two case studies in a Southern African context.

    OpenAIRE

    Hughes-d Aeth, Armand Henry

    1995-01-01

    This thesis examines teacher personal and cultural presage variables within a black South African cultural dimension. I seek to understand what effects value variables have on the mediation of change and to know why these sometimes act as barriers to the implementation of classroom innovation - in this instance, a communicative language teaching approach. Finally, I itemize the implications of value change for the professional development of teachers following ELT INSET ...

  18. Effects of environmental changes and human impact on the functioning of mountain river channels, Carpathians, southern Poland

    Directory of Open Access Journals (Sweden)

    Krzemień Kazimierz

    2015-09-01

    Full Text Available In the northern slope of the Carpathian Mountains and in their foreland, river and stream channels have been significantly transformed by human impact. These transformations result from changing land use in river basins and direct interference with river channels (alluvia extraction, engineering infrastructure, channel straightening. Anthropogenic impacts cause significant changes in the channel system patterns leading to increased impact of erosion. This mainly leads to the channelling of the fluvial system. This article reviews studies of structure and dynamics of Carpathian river channels conducted based on the methodology of collection of data on channel systems, developed in the Department of Geomorphology of the Institute of Geography and Spatial Management, Jagiellonian University.

  19. Monitoring the Genotoxic and Cytotoxic Potential and the Presence of Pesticides and Hydrocarbons in Water of the Sinos River Basin, Southern Brazil.

    Science.gov (United States)

    Bianchi, Eloisa; Lessing, Gustavo; Brina, Karisa Roxo; Angeli, Larissa; Andriguetti, Natália Bordin; Peruzzo, Jaqueline Regina Soares; do Nascimento, Carlos Augusto; Spilki, Fernando Rosado; Ziulkoski, Ana Luiza; da Silva, Luciano Basso

    2017-04-01

    The Sinos River is one of the most polluted rivers in Brazil. The purpose of this work was to monitor the presence of some pesticides and hydrocarbons as well as the genotoxic and cytotoxic potential on HEp-2 cells from water samples collected at seven sites in the Sinos River Basin (SRB), southern Brazil. Nine samples were taken from the three main rivers in the SRB and used as a solution to dilute the HEp-2 cell culture medium after microfiltration. Twenty-four pesticides and 19 hydrocarbons were measured. Cytotoxicity was assessed by methyl thiazolyl tetrazolium (MTT) and neutral red (NR) assays, in which cells were exposed to different concentrations of the water samples for 24 h. Genotoxicity of the microfiltrated raw water samples was assessed by comet assay after 6 and 24 h of exposure. Among the chemicals analyzed, only the 2,4-D, dichloromethane, tetrachloroethene, chloroform, bromodichloromethane, styrene, and toluene were detected, but they were all lower than the limit established by Brazilian regulations. Twenty samples from a total of 60 had a cytotoxic effect in the MTT assay and 30 in the NR assay. The comet assay indicated the presence of genotoxic substances in the water at the seven locations monitored. Temporal and spatial variation was observed in the cytotoxicity and genotoxicity assays. Results indicated that the water in all stretches of the SRB is contaminated and it can cause harmful effects to humans and to the aquatic biota. This HEp-2 cell-line approach can be an additional tool for environmental monitoring.

  20. River-spring connectivity and hydrogeochemical interactions in a shallow fractured rock formation. The case study of Fuensanta river valley (Southern Spain)

    Science.gov (United States)

    Barberá, J. A.; Andreo, B.

    2017-04-01

    In upland catchments, the hydrology and hydrochemistry of streams are largely influenced by groundwater inflows, at both regional and local scale. However, reverse conditions (groundwater dynamics conditioned by surface water interferences), although less described, may also occur. In this research, the local river-spring connectivity and induced hydrogeochemical interactions in intensely folded, fractured and layered Cretaceous marls and marly-limestones (Fuensanta river valley, S Spain) are discussed based on field observations, tracer tests and hydrodynamic and hydrochemical data. The differential flow measurements and tracing experiments performed in the Fuensanta river permitted us to quantify the surface water losses and to verify its direct hydraulic connection with the Fuensanta spring. The numerical simulations of tracer breakthrough curves suggest the existence of a groundwater flow system through well-connected master and tributary fractures, with fast and multi-source flow components. Furthermore, the multivariate statistical analysis conducted using chemical data from the sampled waters, the geochemical study of water-rock interactions and the proposed water mixing approach allowed the spatial characterization of the chemistry of the springs and river/stream waters draining low permeable Cretaceous formations. Results corroborated that the mixing of surface waters, as well as calcite dissolution and CO2 dissolution/exsolution, are the main geochemical processes constraining Fuensanta spring hydrochemistry. The estimated contribution of the tributary surface waters to the spring flow during the research period was approximately 26-53% (Fuensanta river) and 47-74% (Convento stream), being predominant the first component during high flow and the second one during the dry season. The identification of secondary geochemical processes (dolomite and gypsum dissolution and dedolomitization) in Fuensanta spring waters evidences the induced hydrogeochemical

  1. Integrated modelling and management of nutrients and eutrophication in river basin - coast - sea systems: A southern Baltic Sea perspective

    Science.gov (United States)

    Schernewski, Gerald

    2014-05-01

    The Odra river basin (area: 120,000 km2, average discharge: 550 m³/s, annual N-load 60,000 t) and the Oder (Szczecin) Lagoon (687 km²) are the eutrophication hot-spot in the south-western Baltic region. To be able to carry out large scale, spatially integrative analyses, we linked the river basin nutrient flux model MONERIS to the coastal 3D-hydrodynamic and ecosystem model ERGOM. Objectives were a) to analyse the eutrophication history in the river basin and the resulting functional changes in the coastal waters between early 1960's and today and b) to analyse the effects of nitrogen and phosphorus management scenarios in the Oder/Odra river basin on coastal and Baltic Sea water quality. The models show that an optimal river basin management with reduced nutrient loads (e.g. N-load reduction of 35%) would have positive effects on lagoon water quality and algae biomass. The availability of nutrients, N/P ratios and processes like denitrification and nitrogen-fixation would show spatial and temporal changes. It would have positive consequences for ecosystems functions, like the nutrient retention capacity, as well. However, this optimal scenario is by far not sufficient to ensure a good coastal water quality according to the European Water Framework Directive. A "good" water quality in the river will not be sufficient to ensure a "good" water quality in the coastal waters. Further, nitrogen load reductions bear the risk of increased potentially toxic, blue-green algae blooms. The presentation will a) summarize recent results (Schernewski et al. 2009, Schernewski et al. 2011, 2012), b) give an overview how the models were used to provide a comprehensive and consistent set of water quality thresholds and maximum allowable riverine loads for the Water Framework Directive and c) will show the implications for an optimised river basin - lagoon quality management.

  2. Water quality assessment in the "German River of the years 2014/2015": how a case study on the impact of a storm water sedimentation basin displayed impairment of fish health in the Argen River (Southern Germany).

    Science.gov (United States)

    Thellmann, Paul; Kuch, Bertram; Wurm, Karl; Köhler, Heinz-R; Triebskorn, Rita

    2017-01-01

    The present work investigates the impact of discharges from a storm water sedimentation basin (SSB) receiving runoff from a connected motorway in southern Germany. The study lasted for almost two years and was aimed at assessing the impact of the SSB on the fauna of the Argen River, which is a tributary of Lake Constance. Two sampling sites were examined up- and downstream of the SSB effluent. A combination of different diagnostic methods (fish embryo test with the zebrafish, histopathology, micronucleus test) was applied to investigate health impairment and genotoxic effects in indigenous fish as well as embryotoxic potentials in surface water and sediment samples of the Argen River, respectively, in samples of the SSB effluent. In addition, sediment samples from the Argen River and tissues of indigenous fish were used for chemical analyses of 33 frequently occurring pollutants by means of gas chromatography. Furthermore, the integrity of the macrozoobenthos community and the fish population were examined at both investigated sampling sites. The chemical analyses revealed a toxic burden with trace substances (originating from traffic and waste water) in fish and sediments from both sampling sites. Fish embryo tests with native sediment and surface water samples resulted in various embryotoxic effects in exposed zebrafish embryos (Fig. 1). In addition, the health condition of the investigated fish species (e.g., severe alterations in the liver and kidney) provided clear evidence of water contamination at both Argen River sites (Fig. 2). At distinct points in time, some parameters (fish development, kidney and liver histopathology) indicated stronger effects at the sampling site downstream of the SSB effluent than at the upstream site. Our results clearly showed that the SSB cannot be assigned as the main source of pollutants that are released into the investigated Argen River section. Moreover, we showed that there is moderate background pollution with substances

  3. Contribution to the caryological study of the African grass Aristida rhiniochloa Hochst., based on specimens from the Southern Hemisphere

    Directory of Open Access Journals (Sweden)

    Pierre Bourreil

    1972-11-01

    Full Text Available The chromosome number established for Aristida rhiniochloa Hochst. by the study of material from three localities in the Southern Hemisphere confirms the results obtained on material from North Africa. The haploid complement (n = 11 and the diploid number (2n = 22 of this species conform to the basic number x = 11 typical for the Aristideae. It is shown that the caryotype of this species is sub-symmetrical. Preliminary studies o f material from two localities show that the meiotic behaviour conforms to that found in the diploid species with n bivalents.

  4. Contribution to the caryological study of the African grass Aristida rhiniochloa Hochst., based on specimens from the Southern Hemisphere

    Directory of Open Access Journals (Sweden)

    Pierre Bourreil

    1972-12-01

    Full Text Available The chromosome number established for Aristida rhiniochloa Hochst. by the study of material from three localities in the Southern Hemisphere confirms the results obtained on material from North Africa. The haploid complement (n = 11 and the diploid number (2n = 22 of this species conform to the basic number x = 11 typical for the Aristideae. It is shown that the caryotype of this species is sub-symmetrical. Preliminary studies o f material from two localities show that the meiotic behaviour conforms to that found in the diploid species with n bivalents.

  5. Migratory life history of European eel Anguilla anguilla from freshwater regions of the River Asi, southern Turkey and their high otolith Sr:Ca ratios.

    Science.gov (United States)

    Lin, Y-J; Yalçin-Özdilek, S; Iizuka, Y; Gümüş, A; Tzeng, W-N

    2011-03-01

    Otolith Sr:Ca ratios from 32 of 34 European eel Anguilla anguilla collected from three freshwater sites in the River Asi, southern Turkey, indicated that they were resident in fresh water without apparent exposure to salt water since the elver stage. The Sr:Ca ratio criterion indicative of residence in fresh water was more than twice that of values from other European countries. Otolith Sr:Ca ratios of A. anguilla from fresh waters can vary among regions, possibly reflecting regional-specific water chemistry. Hence, the use of Sr:Ca ratios determined in one region to interpret results from a different region might lead to misclassification of migratory life-history types. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

  6. Shakespeare in Southern Africa

    African Journals Online (AJOL)

    Shakespeare in Southern Africa is interested in both literary and theatrical approaches to Shakespeare. Its geographical scope is not confined to Southern Africa. Contributions discussing the legacy of Shakespeare elsewhere in Africa, with a specific focus on the Shakespearean experience in particular African countries, ...

  7. Ethical quandaries in spiritual healing and herbal medicine: A critical analysis of the morality of traditional medicine advertising in southern African urban societies

    Science.gov (United States)

    Munyaradzi, Mawere

    2011-01-01

    This paper critically examines the morality of advertising by practitioners in spiritual healing and herbal medicine heretofore referred to as traditional medicine, in southern African urban societies. While the subject of traditional medicine has been heavily contested in medical studies in the last few decades, the monumental studies on the subject have emphasised the place of traditional medicine in basic health services. Insignificant attention has been devoted to examine the ethical problems associated with traditional medicine advertising. Critical look at the worthiness of some advertising strategies used by practitioners in traditional medicine in launching their products and services on market thus has been largely ignored. Yet, though advertising is key to helping traditional medicine practitioners’ products and services known by prospective customers, this research registers a number of morally negative effects that seem to outweigh the merits that the activity brings to prospective customers. The paper adopts southern African urban societies, and in particular Mozambique, South Africa and Zimbabwe as particular references. The choice of the trio is not accidental, but based on the fact that these countries have in the last few decades been flooded with traditional medicine practitioners/traditional healers from within the continent and from abroad. Most of these practitioners use immoral advertising strategies in communicating to the public the products and services they offer. It is against this background that this paper examines the morality of advertising strategies deployed by practitioners in launching their products and services. To examine the moral worthiness of the advertising strategies used by traditional medical practitioners, I used qualitative analysis of street adverts as well as electronic and print media. From the results obtained through thematic content analysis, the paper concludes that most of the practitioners in traditional

  8. Ethical quandaries in spiritual healing and herbal medicine: a critical analysis of the morality of traditional medicine advertising in southern African urban societies.

    Science.gov (United States)

    Munyaradzi, Mawere

    2011-01-01

    This paper critically examines the morality of advertising by practitioners in spiritual healing and herbal medicine heretofore referred to as traditional medicine, in southern African urban societies. While the subject of traditional medicine has been heavily contested in medical studies in the last few decades, the monumental studies on the subject have emphasised the place of traditional medicine in basic health services. Insignificant attention has been devoted to examine the ethical problems associated with traditional medicine advertising. Critical look at the worthiness of some advertising strategies used by practitioners in traditional medicine in launching their products and services on market thus has been largely ignored. Yet, though advertising is key to helping traditional medicine practitioners' products and services known by prospective customers, this research registers a number of morally negative effects that seem to outweigh the merits that the activity brings to prospective customers. The paper adopts southern African urban societies, and in particular Mozambique, South Africa and Zimbabwe as particular references. The choice of the trio is not accidental, but based on the fact that these countries have in the last few decades been flooded with traditional medicine practitioners/traditional healers from within the continent and from abroad. Most of these practitioners use immoral advertising strategies in communicating to the public the products and services they offer. It is against this background that this paper examines the morality of advertising strategies deployed by practitioners in launching their products and services. To examine the moral worthiness of the advertising strategies used by traditional medical practitioners, I used qualitative analysis of street adverts as well as electronic and print media. From the results obtained through thematic content analysis, the paper concludes that most of the practitioners in traditional

  9. Managing the wetlands. People and rivers: Africa.

    Science.gov (United States)

    Dugan, P

    1993-01-01

    At the current population growth rate in Africa, the population will reach 1 billion by 2010. Water is needed to sustain these people, yet rainfall in Africa is erratic. Africans are already confronting a shortage of freshwater. Agriculture supports 66% of the population of sub-Saharan Africa. Sound agricultural development is needed to curb rural-urban migration, but a constant supply of freshwater is essential. Major rivers (the Limpopo in southern Africa and the Save/Sabi in Zimbabwe and Mozambique) now flow only seasonally. The flows of the Chari-Logona, the Nile, and the Zambezi are falling. Continual mismanagement of Africa's river basins coupled with current projections of global climate change will expand desiccation. All but the White Nile and the Zaire rivers flood seasonally every year, thereby expanding Africa's wetlands. Wetlands have been targeted for development projects (e.g., hydroelectric projects and large dams), largely to meet urban-industrial demands. Development planners tend to ignore the economic value of the wetlands. For example, the Niger Inland Delta sustains 550,000 people, 1 million cattle, and 1 million sheep. Wetlands replenish ground water and serve as natural irrigation. River basin planning often results in environmentally disastrous schemes which do not understand local management practices. Hydrologists, engineers, geologists, and economics design these schemes, but sociologists, anthropologists, and development experts should be included. The unfinished Jonglei Canal in southern Sudan would have adversely affected 400,000 pastoralists. The Volta River Authority's Akosombo Dam displaced 84,000 people and flooded the most productive agricultural land in Ghana. A sustainable future in Africa depends on understanding the interactions of human uses and the ways in which they relate to the natural variations in river flow. The IUCN Wetlands Programme, based on the principles of the World Conservation Strategy, is working with

  10. Identification and simulation of space–time variability of past hydrological drought events in the Limpopo River basin, southern Africa

    NARCIS (Netherlands)

    Trambauer, P.; Maskey, S.; Werner, M.; Pappenberger, F.; Van Beek, L.P.H.; Uhlenbrook, S.

    2014-01-01

    Droughts are widespread natural hazards and in many regions their frequency seems to be increasing. A finer-resolution version (0.05° × 0.05°) of the continental-scale hydrological model PCRaster Global Water Balance (PCR-GLOBWB) was set up for the Limpopo River basin, one of the most water-stressed

  11. Distribution and Source Apportionment of Polycyclic Aromatic Hydrocarbons (PAHs) in Forest Soils from Urban to Rural Areas in the Pearl River Delta of Southern China

    Science.gov (United States)

    Xiao, Yihua; Tong, Fuchun; Kuang, Yuanwen; Chen, Bufeng

    2014-01-01

    The upper layer of forest soils (0–20 cm depth) were collected from urban, suburban, and rural areas in the Pearl River Delta of Southern China to estimate the distribution and the possible sources of polycyclic aromatic hydrocarbons (PAHs). Total concentrations of PAHs in the forest soils decreased significantly along the urban–suburban–rural gradient, indicating the influence of anthropogenic emissions on the PAH distribution in forest soils. High and low molecular weight PAHs dominated in the urban and rural forest soils, respectively, implying the difference in emission sources between the areas. The values of PAH isomeric diagnostic ratios indicated that forest soil PAHs were mainly originated from traffic emissions, mixed sources and coal/wood combustion in the urban, suburban and rural areas, respectively. Principal component analysis revealed that traffic emissions, coal burning and residential biomass combustion were the three primary contributors to forest soil PAHs in the Pearl River Delta. Long range transportation of PAHs via atmosphere from urban area might also impact the PAHs distribution in the forest soils of rural area. PMID:24599040

  12. NOTES ON THE BIOLOGY AND ECOLOGY OF Sudanonautes floweri(DE MAN, 1901; CRUSTACEA: BRACHYURA: POTAMOIDEA: POTAMONAUTIDAE IN RIVER OGBOMWEN, SOUTHERN NIGERIA

    Directory of Open Access Journals (Sweden)

    FRANCIS O ARIMORO

    2008-01-01

    Full Text Available Investigation into some aspects of the biology and ecology of the freshwater crab, Sudanonautes floweri(De Man, 1901 in River Ogbomwen, Edo State, southern, Nigeria was carried out between February and July 2006. The study revealed that the crab species were widespread and abundant in the river. Abundance in terms of number and biomass was more during the wet season with at a peak in the months of June and July. The crab grew allometrically attaining a maximum total length and weight of 11.5 cm and 65 g respectively. The condition factor ranged from 8.60-9.45. These values did not vary with size and sex of the crab but showed seasonal variations. Females of Sudanonautes floweriwere more abundant although not significantly different from the expected 1:1 ratio. There were some sexually matured females with stages III gonad development. Fecundity estimate ranged from 400 to 650 eggs. The gonadosomatic index varied between 14.97 and 24.11%. Feeding habits varied slightly with size with larger sized crabs feeding on more and varied food particles. Generally, Sudanonautes flowerifed predominantly on detritus, crustaceans, fish, algae, filaments, diatoms and sand grains.

  13. The impact of anthropogenic factors on the occurrence of molybdenum in stream and river sediments of central Upper Silesia (Southern Poland

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    Pasieczna Anna

    2017-12-01

    Full Text Available In our study, a detailed survey was conducted with the aim to determine the distribution and possible anthropogenic sources of molybdenum in river and stream sediments in the central Upper Silesian Industrial Region (Southern Poland, where for many years, iron and zinc smelters as well as coking and thermal power plants were operating. At the same time, this has also been a residential area with the highest population density in the country. Sediments (1397 samples in total were collected from rivers and streams, and analysed for the content of molybdenum and 22 other elements. ICP-AES and CV-AAS methods were applied for the determination of the content of elements. The studies revealed molybdenum content in the range of 5 mg·kg−1. The spatial distribution of molybdenum demonstrated by the geochemical map has indicated that the principal factor determining its content in sediments is the discharge of wastewater from steelworks and their slag heaps. Another source of this element in sediments has been the waste of the historical mining of zinc ore and metallurgy of this metal. Additionally, molybdenum migration from landfills of power plants, coal combustion and Mo emission to the atmosphere and dust fall-out have been significant inputs of Mo pollution to the sediments.

  14. Feeding ecology of the freshwater crab Trichodactylus borellianus (Decapoda: Trichodactylidae in the floodplain of the Paraná River, southern South America

    Directory of Open Access Journals (Sweden)

    Verónica Williner

    2013-09-01

    Full Text Available Freshwater crabs are not commonly considered to be an important group in trophic webs, and this might be due to a lack of knowledge about their trophic roles in aquatic ecosystems. Trichodactylus borellianus is one of the most common and widely distributed freshwater crabs in the floodplains of the southern South American rivers. The main objective of the present study was to examine the trophic role of T. borellianus, in the floodplain of the Paraná River, and its relationships with the freshwater littoral community. The trophic spectrum of this species was characterized for both sexes and individuals of different sizes (adults and juveniles, throughout daily and seasonal cycles. Samples were collected from the aquatic vegetation of three shallow lakes. The diet composition and the feeding activity of T. borellianus were evaluated through the examination of the stomach contents and their degree of emptiness. This crab species consumed several plant and animal items, including amoebas, rotifers, oligochaetes, copepods, cladocerans, and insect larvae. Moreover, this species consumes filamentous and unicellular algae, diatoms, fungi, and macrophytic remains. The predatory habits varied with the season and time of day, and variations in the feeding activity of the juveniles and adults were detected and documented. The diversity of food items eaten by this crab suggests that its trophic role in the community as an omnivore and opportunistic predator provides a connection among several trophic levels from both aquatic and terrestrial communities.

  15. The Quequén Salado river basin: Geology and biochronostratigraphy of the Mio-Pliocene boundary in the southern Pampean plain, Argentina

    Science.gov (United States)

    Beilinson, E.; Gasparini, G. M.; Tomassini, R. L.; Zárate, M. A.; Deschamps, C. M.; Barendregt, R. W.; Rabassa, J.

    2017-07-01

    The Quequén Salado river basin has been the focus of several contributions since the first decades of the XX century, namely dealing with the general geological features of the deposits and with the vertebrate remains. In this paper, the Neogene geological history documented by the Quequén Salado river exposures is reconstructed by means of stratigraphic, sedimentological and paleomagnetic studies along with the paleontological analysis of vertebrate remains. The study area is a crucial setting not only to better understand the evolution of the southern Pampas basin during the late Miocene-early Pliocene interval, but also to test the validity of the biochronologic and biostratigraphic schemes, especially the ;Irenense;. A geological model for the Quequén Salado river valley is proposed: a case of downcutting and headward erosion that contributes with a coherent interpretation to explain the spatial distribution of facies and fossil taxa: the younger in the distal sector of the Quequén Salado middle basin and the older in the lower basin. The sedimentary record is believed to represent the distal reaches of a distributary fluvial system that drained from the Ventania ranges. The stratigraphic section of Paso del Indio Rico results a key stratigraphic site to fully understand the stratigraphic nature of the boundary between the Miocene and the Pliocene (the Huayquerian and Montehermosan stages/ages). In this sense, two stratigraphically superposed range zones have been recognized in the area: Xenodontomys ellipticus Range Zone (latest Miocene-early Pliocene; late Huayquerian), and Eumysops laeviplicatus Range Zone (early Pliocene; Montehermosan). Taking into account the available geological and paleontological evidences, the ;Irenense; would not represent a valid biostratigraphic unit, since, according to the geological model here proposed, it would be represented by elements of the Xenodontomys ellipticus Range Zone in the lower QS basin and by elements of the

  16. Role of the Angola Low in modulating southern African austral summer rainfall and relationships with synoptic and interannual modes of variability

    Science.gov (United States)

    Crétat, Julien; Pohl, Benjamin; Dieppois, Bastien

    2017-04-01

    The Angola Low has been suggested in many previous studies to be an important regional feature governing southern African rainfall variability during austral summer, which is, in particular, expressed through modulations of El Niño Southern Oscillation (ENSO) impacts on rainfall at the interannual timescale. Here, we analyse a variety of state-of-the-art reanalyses (NCEP2, ERA-Interim and MERRA2) and rainfall data (in situ rain-gauges and satellite-derived products) for: i) identifying the recurrent regimes of the Angola Low (position and intensity) at the daily timescale; ii) diagnosing how they modulate the spatio-temporal variability of austral summer rainfall; and iii) examining their relationships with synoptic convective regimes and ENSO, both at the interannual timescale. The recurrent regimes of the Angola Low are identified over the 1980-2015 period by applying a cluster analysis to daily 700-hPa wind vorticity anomalies over the Angola sector from November to March. The exact number and morphological properties of vorticity regimes vary significantly among the reanalyses, in particular when using the lowest spatial resolution reanalysis (i.e., NCEP2) that leads to detect less diversity, smoothest patterns and weakest intensity across the recurrent regimes. Despite such uncertainties, the regimes describing active Angola Low are quite robust among the reanalyses. Three preferential locations (locked over eastern Angola, shifted few degrees eastward or south-westward), which significantly impact on the rainfall spatial distribution over tropical and subtropical southern Africa, are identified. Independently from its location, Angola Low favours moisture advection from the southwest Indian Ocean and reduces moisture export towards the southeast Atlantic, hence contributing to increase moisture convergence over the subcontinent. Lead/lag correlations with synoptic convective regimes suggest that Angola Low may be a local precursor of tropical

  17. Incorporating trnH-psbA to the core DNA barcodes improves significantly species discrimination within southern African Combretaceae

    Directory of Open Access Journals (Sweden)

    Jephris Gere

    2013-12-01

    Full Text Available Recent studies indicate that the discriminatory power of the core DNA barcodes (rbcLa + matK for land plants may have been overestimated since their performance have been tested only on few closely related species. In this study we focused mainly on how the addition of complementary barcodes (nrITS and trnH-psbA to the core barcodes will affect the performance of the core barcodes in discriminating closely related species from family to section levels. In general, we found that the core barcodes performed poorly compared to the various combinations tested. Using multiple criteria, we finally advocated for the use of the core + trnH-psbA as potential DNA barcode for the family Combretaceae at least in southern Africa. Our results also indicate that the success of DNA barcoding in discriminating closely related species may be related to evolutionary and possibly the biogeographic histories of the taxonomic group tested.

  18. Determinants of persistence and tolerance of carnivores on Namibian ranches: implications for conservation on Southern African private lands.

    Science.gov (United States)

    Lindsey, Peter Andrew; Havemann, Carl Peter; Lines, Robin; Palazy, Lucille; Price, Aaron Ernest; Retief, Tarryn Anne; Rhebergen, Tiemen; Van der Waal, Cornelis

    2013-01-01

    Changing land use patterns in southern Africa have potential to dramatically alter the prospects for carnivore conservation. Understanding these influences is essential for conservation planning. We interviewed 250 ranchers in Namibia to assess human tolerance towards and the distribution of large carnivores. Cheetahs (Acinonyx jubatus), leopards (Panthera pardus) and brown hyaenas (Hyaena brunnea) were widely distributed on Namibian farmlands, spotted hyaenas (Crocuta crocuta) had a narrower distribution, and wild dogs (Lycaon pictus) and lions (Panthera leo) are largely limited to areas near source populations. Farmers were most tolerant of leopards and least tolerant of lions, wild dogs and spotted hyaenas. Several factors relating to land use correlated consistently with carnivore-presence and landowner tolerance. Carnivores were more commonly present and/or tolerated where; wildlife diversity and biomass were higher; income from wildlife was higher; income from livestock was lower; livestock biomass was lower; in conservancies; game fencing was absent; and financial losses from livestock depredation were lower. Efforts to create conditions whereby the costs associated with carnivores are lowest, and which confer financial value to them are likely to be the most effective means of promoting carnivore conservation. Such conditions are achieved where land owners pool land to create conservancies where livestock are replaced with wildlife (or where livestock husbandry is improved) and where wildlife generates a significant proportion of ranch income. Additional measures, such as promoting improved livestock husbandry and educational outreach efforts may also help achieve coexistence with carnivores. Our findings provide insights into conditions more conducive to the persistence of and tolerance towards large carnivores might be increased on private (and even communal) lands in Namibia, elsewhere in southern and East Africa and other parts of the world where

  19. Correlates of male circumcision in Eastern and Southern African countries: establishing a baseline prior to VMMC Scale-up.

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    Khai Hoan Tram

    Full Text Available BACKGROUND: Despite the importance of male circumcision (MC prevalence to HIV prevention efforts in Eastern and Southern Africa, there has been no systematic analysis on the correlates of male circumcision. This analysis identifies correlates of MC in 12 countries in the region with available data. METHODS: Data from the male questionnaire of DHS surveys collected between 2006-2011 in Ethiopia, Kenya, Lesotho, Malawi, Mozambique, Namibia, Rwanda, Swaziland, Tanzania, Uganda, Zambia, and Zimbabwe were analyzed. The dependent variable was self-reported male circumcision status. Independent variables included age, education, wealth quintile, place of residence, ethnicity, religion and region. Bivariate and multivariate analyses were conducted separately for each country. RESULTS: MC prevalence ranged from 8.2 percent in Swaziland to 92.2 percent in Ethiopia. Bivariate analyses showed a consistent positive association between age (being older and male circumcision. Education, wealth quintile, and place of residence were either not significantly related or differed in the direction of the relationship by country. Multivariate logistic regression showed three variables consistently associated with MC status: age (being older, religion (being Muslim and ethnicity. DISCUSSION: These data were collected prior to the scale-up of voluntary medical male circumcision (VMMC programs in 11 of the 12 countries. As the VMMC scale-up intensifies in countries across Eastern and Southern Africa, the correlates of VMMC are likely to change, with (younger age and education emerging as key correlates of VMMC performed in medical settings. The centuries-long tradition among Muslims to circumcise should continue to favor MC among this group. Non-circumcising ethnicities may become more open to MC if promoted as a health practice for decreasing HIV risk.

  20. Determinants of persistence and tolerance of carnivores on Namibian ranches: implications for conservation on Southern African private lands.

    Directory of Open Access Journals (Sweden)

    Peter Andrew Lindsey

    Full Text Available Changing land use patterns in southern Africa have potential to dramatically alter the prospects for carnivore conservation. Understanding these influences is essential for conservation planning. We interviewed 250 ranchers in Namibia to assess human tolerance towards and the distribution of large carnivores. Cheetahs (Acinonyx jubatus, leopards (Panthera pardus and brown hyaenas (Hyaena brunnea were widely distributed on Namibian farmlands, spotted hyaenas (Crocuta crocuta had a narrower distribution, and wild dogs (Lycaon pictus and lions (Panthera leo are largely limited to areas near source populations. Farmers were most tolerant of leopards and least tolerant of lions, wild dogs and spotted hyaenas. Several factors relating to land use correlated consistently with carnivore-presence and landowner tolerance. Carnivores were more commonly present and/or tolerated where; wildlife diversity and biomass were higher; income from wildlife was higher; income from livestock was lower; livestock biomass was lower; in conservancies; game fencing was absent; and financial losses from livestock depredation were lower. Efforts to create conditions whereby the costs associated with carnivores are lowest, and which confer financial value to them are likely to be the most effective means of promoting carnivore conservation. Such conditions are achieved where land owners pool land to create conservancies where livestock are replaced with wildlife (or where livestock husbandry is improved and where wildlife generates a significant proportion of ranch income. Additional measures, such as promoting improved livestock husbandry and educational outreach efforts may also help achieve coexistence with carnivores. Our findings provide insights into conditions more conducive to the persistence of and tolerance towards large carnivores might be increased on private (and even communal lands in Namibia, elsewhere in southern and East Africa and other parts of the world