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Sample records for southern sudan implications

  1. Trachoma in Western Equatoria State, Southern Sudan: Implications for National Control

    PubMed Central

    Kur, Lucia W.; Picon, Diana; Adibo, Obec; Robinson, Emily; Sabasio, Anthony; Edwards, Tansy; Ndyaba, Aggrey; Rumunu, John; Lewis, Karinya; Lado, Mounir; Kolaczinski, Jan

    2009-01-01

    Background Trachoma is thought to be common over large parts of Southern Sudan. However, many areas of the country, particularly west of the Nile, have not yet been surveyed. The aim of this study was to confirm whether trachoma extends into Western Equatoria State from neighboring Central Equatoria, where trachoma is highly prevalent, and whether intervention with the SAFE strategy is required. Methods and Findings Population-based cross-sectional surveys were conducted using a two-stage cluster random sampling method to select the study population. Subjects were examined for trachoma by experienced graders using the World Health Organization (WHO) simplified grading scheme. Two counties thought to be most likely to have trachoma were surveyed, Maridi and Mundri. In Maridi, prevalence of one of the signs of active trachoma (trachomatous inflammation-follicular (TF)) in children aged 1–9 years was 0.4% (95% confidence interval (CI), 0.0%–0.8%), while no children showing the other possible sign, trachomatous inflammation-intense (TI), were identified. No trachomatous trichiasis (TT) was found in those aged under 15, and prevalence was 0.1% (95% CI, 0.0%–0.4%) in those aged 15 years and above. In Mundri, active trachoma was also limited to signs of TF, with a prevalence of 4.1% (95% CI, 1.4%–6.9%) in children aged 1–9 years. Again, no TT was found in those aged under 15, and prevalence in those aged 15 years and above was 0.3% (95% CI, 0.0%–0.8%). Conclusion Trachoma prevalence in the east of Western Equatoria State is below the WHO recommended intervention threshold for mass drug administration of antibiotic treatment in all villages. However, the prevalence of TF and TT in some villages, particularly in Mundri County, is sufficiently high to warrant targeted interventions at the community level. These results demonstrate that trachoma is not a major public health problem throughout Southern Sudan. Further studies will be required to determine trachoma prevalence in other areas, particularly west of the Nile, but there are presently no resources to survey each county. Studies should thus be targeted to areas where collection of new data would be most informative. PMID:19636366

  2. Regional geodynamic implications of the May July 1990 earthquake sequence in southern Sudan

    NASA Astrophysics Data System (ADS)

    Gaulon, R.; Chorowicz, J.; Vidal, G.; Romanowicz, B.; Rouit, G.

    1992-08-01

    Several large earthquakes occurred in the south of the Sudan in May and July 1990. The focal mechanism solution of the main shock (May 20, 1990), one of the largest events in Africa ever recorded, shows left-lateral strike-slip faulting. One of the nodal planes is parallel to the Aswa fault zone, a major Proterozoic tectonic feature. A line connecting the epicenters of the main events of May and July also strikes in the same direction. Field observations and satellite imagery also indicate left-lateral horizontal reactivation movement along this large structural feature during Cenozoic times. The fault plane solutions of the Harvard Centroid Moment Tensor catalog for earthquakes between 1977 and 1989 in the East African Rift System show extensional horizontal slip component striking about northwest-southeast. All these facts lead the interpretation of this wide, diffuse fault zone as an active intracontinental transform area linking the two main branches of the rift system. If one considers this displacement and the slip directions obtained from the centroid moment tensors solutions as characterizing the motion between the Nubian and Somalian plates, new constraints on the regional geodynamics can be inferred; the Somalian block appears to be moving southeastwards relative to the African block. The rupture occurred in at least three steps, affecting a zone roughly 50 km long. The large aftershocks of 24th May have significantly different fault plane solutions, indicating the complexity of the rupture process. Nevertheless, the tension axes of the main aftershocks always strike N-S. Thus there is an exchange of the intermediate and pressure axes for the aftershocks on May 24 relative to the main shock.

  3. Cholera outbreak--southern Sudan, 2007.

    PubMed

    2009-04-10

    Vibrio cholerae causes cholera, an acute infectious diarrheal disease that can result in death without appropriate therapy, depending on the severity of the disease. War, poverty, inadequate sanitation, and large numbers of refugees and internally displaced persons (IDPs) are major precursors to cholera outbreaks. In 2005, Southern Sudan ended its 22-year civil war with North Sudan; as a result, IDPs and refugees are returning to the south. During April--June 2007, investigators from the Southern Sudan Field Epidemiology and Laboratory Training Program (SS-FELTP) and CDC investigated a cholera outbreak in the town of Juba, Southern Sudan. This report summarizes the results of that investigation, which found that 3,157 persons were diagnosed with suspected cholera during January--June 2007, with 74 deaths resulting from the disease. An environmental investigation revealed suboptimal hygiene practices and a lack of water and sanitation infrastructure in Juba. A case-control study indicated that persons less likely to have cholera were more likely to have consumed hot meals containing meat during the outbreak. Contaminated food or water were not identified as possible sources of the cholera outbreak in Juba. However, this might be attributed to limitations of the study, including small sample size. Cholera can reach epidemic proportions if adequate control measures are not implemented early. Mass media campaigns are important for current and new residents in Juba to understand the importance of proper food handling, clean water, and optimal hygiene practices to prevent the spread of cholera. PMID:19357634

  4. Integrated Mapping of Neglected Tropical Diseases: Epidemiological Findings and Control Implications for Northern Bahr-el-Ghazal State, Southern Sudan

    PubMed Central

    Sturrock, Hugh J. W.; Picon, Diana; Sabasio, Anthony; Oguttu, David; Robinson, Emily; Lado, Mounir; Rumunu, John; Brooker, Simon; Kolaczinski, Jan H.

    2009-01-01

    Background There are few detailed data on the geographic distribution of most neglected tropical diseases (NTDs) in post-conflict Southern Sudan. To guide intervention by the recently established national programme for integrated NTD control, we conducted an integrated prevalence survey for schistosomiasis, soil-transmitted helminth (STH) infection, lymphatic filariasis (LF), and loiasis in Northern Bahr-el-Ghazal State. Our aim was to establish which communities require mass drug administration (MDA) with preventive chemotherapy (PCT), rather than to provide precise estimates of infection prevalence. Methods and Findings The integrated survey design used anecdotal reports of LF and proximity to water bodies (for schistosomiasis) to guide selection of survey sites. In total, 86 communities were surveyed for schistosomiasis and STH; 43 of these were also surveyed for LF and loiasis. From these, 4834 urine samples were tested for blood in urine using Hemastix reagent strips, 4438 stool samples were analyzed using the Kato-Katz technique, and 5254 blood samples were tested for circulating Wuchereria bancrofti antigen using immunochromatographic card tests (ICT). 4461 individuals were interviewed regarding a history of ‘eye worm’ (a proxy measure for loiasis) and 31 village chiefs were interviewed regarding the presence of clinical manifestations of LF in their community. At the village level, prevalence of Schistosoma haematobium and S. mansoni ranged from 0 to 65.6% and from 0 to 9.3%, respectively. The main STH species was hookworm, ranging from 0 to 70% by village. Infection with LF and loiasis was extremely rare, with only four individuals testing positive or reporting symptoms, respectively. Questionnaire data on clinical signs of LF did not provide a reliable indication of endemicity. MDA intervention thresholds recommended by the World Health Organization were only exceeded for urinary schistosomiasis and hookworm in a few, yet distinct, communities. Conclusion This was the first attempt to use an integrated survey design for this group of infections and to generate detailed results to guide their control over a large area of Southern Sudan. The approach proved practical, but could be further simplified to reduce field work and costs. The results show that only a few areas need to be targeted with MDA of PCT, thus confirming the importance of detailed mapping for cost-effective control. PMID:19859537

  5. Southern Sudan: an opportunity for NTD control and elimination?

    PubMed

    Rumunu, John; Brooker, Simon; Hopkins, Adrian; Chane, Fasil; Emerson, Paul; Kolaczinski, Jan

    2009-07-01

    Southern Sudan has been ravaged by decades of conflict and is thought to have one of the highest burdens of neglected tropical diseases (NTDs) in the world. Health care delivery, including efforts to control or eliminate NTDs, is severely hampered by a lack of infrastructure and health systems. However, the post-conflict environment and Southern Sudan's emerging health sector provide the unprecedented opportunity to build new, innovative programmes to target NTDs. This article describes the current status of NTDs and their control in Southern Sudan and outlines the opportunities for the development of evidence-based, innovative implementation of NTD control. PMID:19540164

  6. Yellow Fever Outbreak, Imatong, Southern Sudan

    PubMed Central

    Ofula, Victor O.; Sang, Rosemary C.; Konongoi, Samson L.; Sow, Abdourahmane; De Cock, Kevin M.; Tukei, Peter M.; Okoth, Fredrick A.; Swanepoel, Robert; Burt, Felicity J.; Waters, Norman C.; Coldren, Rodney L.

    2004-01-01

    In May 2003, the World Health Organization received reports about a possible outbreak of a hemorrhagic disease of unknown cause in the Imatong Mountains of southern Sudan. Laboratory investigations were conducted on 28 serum samples collected from patients in the Imatong region. Serum samples from 13 patients were positive for immunoglobulin M antibody to flavivirus, and serum samples from 5 patients were positive by reverse transcription–polymerase chain reaction with both the genus Flavivirus–reactive primers and yellow fever virus–specific primers. Nucleotide sequencing of the amplicons obtained with the genus Flavivirus oligonucleotide primers confirmed yellow fever virus as the etiologic agent. Isolation attempts in newborn mice and Vero cells from the samples yielded virus isolates from five patients. Rapid and accurate laboratory diagnosis enabled an interagency emergency task force to initiate a targeted vaccination campaign to control the outbreak. PMID:15207058

  7. Sudan.

    PubMed

    1985-08-01

    The Sudan's population characteristics, geographical features, history, political conditions, and foreign relations are profiled. The 1984 population of Sudan has been estimated at 21.1 million, with an estimated annual growth rate of 3.0%. Approximately 25% of the Sudanese population resides in urban areas. Major religions are Islam, indigenous beliefs (in southern Sudan), and Christianity. The official language is Arabic, although English and tribal languages are also spoken. Education is compulsory for 9 years, but the attendance rate is only 48%. The infant mortality rate is 118.0/1000 live births, and life expectancy is 47 years. 78.4% of the work force is engaged in agriculture, 9.8% in industry and commerce, and 6% in government. The estimated gross national product for 1981-83 was $27.36 billion, with an estimated annual growth rate of 2.7% in 1982-83. Per capit income was approximately $361 in 1982, with an average annual inflation rate of 20-30%. Sudan's population is composed of 2 distinct cultures, Arab and black African, and effective collaboration between them poses one of the nation's principal internal problems. The 5 northern regions cover almost 2/3 of Sudan and include most urban centers. Most of the 13 million Sudanese who live in this area are Arabic-speaking Muslims of several distinct tribal groups. The southern region has a population of about 5.5 million and a predominantly rural, subsistence economy. The south also contains many tribal groups and uses many more languages than the north. Sudan's primary resources are agricultural. Although the country is trying to diversify its cash crops, cotton and cottonseed account for more than 50% of export earnings. Another large export crop is gum arabic. Grain sorghum is the principal food crop, and wheat is grown for domestic consumption. Livestock production has vast potential and many animals, particularly camels and sheep, are exported to other Arab countries. The inadequate transportation system is a major hindrance to economic development. PMID:12178062

  8. Viewing the Reconstruction of Primary Schooling in Southern Sudan through Education Data, 2006-2009

    ERIC Educational Resources Information Center

    Kim, HyeJin; Moses, Kurt D.; Jang, Bosun; Wils, Annababette

    2011-01-01

    After one of the longest wars in the history of Africa, Southern Sudan accomplished one of the world's quickest education reconstruction programmes. Once the Comprehensive Peace Agreement (CPA) was signed in 2005, the international donor community and the government and people of Southern Sudan united under a common goal: to increase access to…

  9. Ticks infesting animals in the Sudan and Southern Sudan: past and current status.

    PubMed

    Elghali, Ahmed A; Hassan, Shawgi M

    2012-01-01

    In this review, we collate information about ticks identified in different parts of the Sudan and South Sudan since 1956 in order to identify gaps in tick prevalence and create a map of tick distribution. This will avail basic data for further research on ticks and policies for the control of tick-borne diseases. In this review, we discuss the situation in the Republic of South Sudan as well as Sudan. For this purpose we have divided Sudan into four regions, namely northern Sudan (Northern and River Nile states), central Sudan (Khartoum, Gazera, White Nile, Blue Nile and Sennar states), western Sudan (North and South Kordofan and North, South and West Darfour states) and eastern Sudan (Red Sea, Kassala and Gadarif states). PMID:23327330

  10. [Sudan].

    PubMed

    The capital of Sudan is Khartoum. As of 1995, Sudan had a population of 28.1 million governed by a military, Islamic regime. 1994 gross national product and per capita income were, respectively, $5.9 billion and $250. In 1994, Sudan owed $18 billion, then being serviced at $1.3 billion. For the same year, Sudan exported $609 million in goods and services and imported $2.209 billion. As of 1995, the population was growing in size by 2.7% annually. In 1992-93, life expectancy at birth was 53 years, the infant mortality rate was 78 per 1000 births, 51% had access to health services, and 48% had access to drinkable water. Other data are presented on the country's topography, climate and vegetation, demographics, principal cities, population distribution, religions, political structure, economics and finances, foreign commerce, and transportation and communications. PMID:12347111

  11. Plight of a displaced woman in southern Sudan.

    PubMed

    Ogana, W

    1993-01-01

    Southern Sudanese have been displaced due to tribal conflicts and civil war between the Islamic Khartoum government in the North and the predominantly Christian South. This article narrates the plight of displaced Southern Sudanese women, particularly that of a woman named Rebecca Akwach during her journey towards Nzara to escape air raids by the Khartoum government. The war that plagued Southern Sudan for the past 11 years has burdened numerous women with the responsibility of bringing up their children single-handedly. Most of the husbands have been killed in battle, separated through displacement, or have fled to other countries. Approximately 500 displaced people, including pregnant women, have walked some 300 km westward to a small town in western Ethiopia. During their ordeal, meals was reduced to once daily or none at all, while others barter whatever valuables they have for food. Malnutrition, malaria, diarrhea, respiratory tract infection and measles were prevalent. Pregnant women have an added burden of carrying valuables and small children who cannot walk 10 km a day. Akwach and other sojourners are now in Nzara and are waiting for the allocation of land where they can temporarily settle. PMID:12349363

  12. Phylogenetic and Ecologic Perspectives of a Monkeypox Outbreak, Southern Sudan, 2005

    PubMed Central

    Emerson, Ginny L.; Carroll, Darin S.; Zhao, Hui; Li, Yu; Reynolds, Mary G.; Karem, Kevin L.; Olson, Victoria A.; Lash, R. Ryan; Davidson, Whitni B.; Smith, Scott K.; Levine, Rebecca S.; Regnery, Russell L.; Sammons, Scott A.; Frace, Michael A.; Mutasim, Elmangory M.; Karsani, Mubarak E. M.; Muntasir, Mohammed O.; Babiker, Alimagboul A.; Opoka, Langova; Chowdhary, Vipul; Damon, Inger K.

    2013-01-01

    Identification of human monkeypox cases during 2005 in southern Sudan (now South Sudan) raised several questions about the natural history of monkeypox virus (MPXV) in Africa. The outbreak area, characterized by seasonally dry riverine grasslands, is not identified as environmentally suitable for MPXV transmission. We examined possible origins of this outbreak by performing phylogenetic analysis of genome sequences of MPXV isolates from the outbreak in Sudan and from differing localities. We also compared the environmental suitability of study localities for monkeypox transmission. Phylogenetically, the viruses isolated from Sudan outbreak specimens belong to a clade identified in the Congo Basin. This finding, added to the political instability of the area during the time of the outbreak, supports the hypothesis of importation by infected animals or humans entering Sudan from the Congo Basin, and person-to-person transmission of virus, rather than transmission of indigenous virus from infected animals to humans. PMID:23347770

  13. Collaborative Evaluation and Market Research Converge: An Innovative Model Agricultural Development Program Evaluation in Southern Sudan

    ERIC Educational Resources Information Center

    O'Sullivan, John M.; O'Sullivan, Rita

    2012-01-01

    In June and July 2006 a team of outside experts arrived in Yei, Southern Sudan through an AID project to provide support to a local agricultural development project. The team brought evaluation, agricultural marketing and financial management expertise to the in-country partners looking at steps to rebuild the economy of the war ravaged region. A

  14. Collaborative Evaluation and Market Research Converge: An Innovative Model Agricultural Development Program Evaluation in Southern Sudan

    ERIC Educational Resources Information Center

    O'Sullivan, John M.; O'Sullivan, Rita

    2012-01-01

    In June and July 2006 a team of outside experts arrived in Yei, Southern Sudan through an AID project to provide support to a local agricultural development project. The team brought evaluation, agricultural marketing and financial management expertise to the in-country partners looking at steps to rebuild the economy of the war ravaged region. A…

  15. Jebel Moya (Sudan): new dates from a mortuary complex at the southern Meroitic frontier

    PubMed Central

    Brass, Michael; Schwenniger, Jean-Luc

    2013-01-01

    This paper proposes a new chronology for the burial complex at Jebel Moya, south-central Sudan. It reassesses the body of evidence from Sir Henry Wellcome's original 1911–1914 excavations in order to place the site within a firm chronological framework by: (a) applying an attribute-based approach to discern discrete pottery assemblages; and (b) applying initial OSL dates to facilitate the reliable dating of this site for the first time. Jebel Moya is re-interpreted as a burial complex situated on the southern periphery of the late Meroitic state, and its potential to serve as a chronological and cultural reference point for future studies in south-central and southern Sudan is outlined. PMID:25400300

  16. Targeting Trachoma Control through Risk Mapping: The Example of Southern Sudan

    PubMed Central

    Clements, Archie C. A.; Kur, Lucia W.; Gatpan, Gideon; Ngondi, Jeremiah M.; Emerson, Paul M.; Lado, Mounir; Sabasio, Anthony; Kolaczinski, Jan H.

    2010-01-01

    Background Trachoma is a major cause of blindness in Southern Sudan. Its distribution has only been partially established and many communities in need of intervention have therefore not been identified or targeted. The present study aimed to develop a tool to improve targeting of survey and control activities. Methods/Principal Findings A national trachoma risk map was developed using Bayesian geostatistics models, incorporating trachoma prevalence data from 112 geo-referenced communities surveyed between 2001 and 2009. Logistic regression models were developed using active trachoma (trachomatous inflammation follicular and/or trachomatous inflammation intense) in 6345 children aged 1–9 years as the outcome, and incorporating fixed effects for age, long-term average rainfall (interpolated from weather station data) and land cover (i.e. vegetation type, derived from satellite remote sensing), as well as geostatistical random effects describing spatial clustering of trachoma. The model predicted the west of the country to be at no or low trachoma risk. Trachoma clusters in the central, northern and eastern areas had a radius of 8 km after accounting for the fixed effects. Conclusion In Southern Sudan, large-scale spatial variation in the risk of active trachoma infection is associated with aridity. Spatial prediction has identified likely high-risk areas to be prioritized for more data collection, potentially to be followed by intervention. PMID:20808910

  17. Interactions and Pastoralism Along the Southern and Southeastern Frontiers of the Meroitic State, Sudan

    PubMed Central

    2016-01-01

    The Nilotic Meroitic state, in what is now the Sudan, existed from the late fourth century BC until the mid fourth century AD. It has come to be regarded in recent years as an African segmentary state with a prestige-goods economy, less centralised than, for example, Egypt, with direct control by the ruling family diminished outside the Shendi Reach (central Sudan). Outbound trade from its capital Meroe included ebony, elephants, gold, iron, ivory and ostrich feathers. Trade routes criss-crossed the desert and extended down the Nile river to Greco-Roman Egypt, as well as through Red Sea ports to several Middle Eastern destinations including Egypt. Using the southern and southeastern reaches of the Meroitic state as a case study, I argue that to conceptualise the frontier peripheries of early states as borders is to misunderstand their internal dynamics (movements of people, fluid social networks and regional exchange systems). Each region had its own distinctive form of power relations. Examining how communities in these frontier zones were constituted, inscribed their identities in the landscape and facilitated trade in relation to the core of the Meroitic state in the Shendi Reach draws attention to the fluidity and continual renegotiation of state–pastoral relations. PMID:27158190

  18. The epidemiology of trachoma in Eastern Equatoria and Upper Nile States, southern Sudan.

    PubMed Central

    Ngondi, Jeremiah; Onsarigo, Alice; Adamu, Liknaw; Matende, Ibrahim; Baba, Samson; Reacher, Mark; Emerson, Paul; Zingeser, James

    2005-01-01

    OBJECTIVE: Limited surveys and anecdotal data indicate that trachoma is endemic in the states of Eastern Equatoria and Upper Nile in southern Sudan. However, its magnitude and geographical distribution are largely unknown. We conducted surveys to ascertain the prevalence and geographical distribution of trachoma, and to identify targets for control interventions. METHODS: Population-based cross-sectional surveys were conducted in nine sites in southern Sudan between September 2001 and June 2004. Two-stage random cluster sampling with probability proportional to size was used to select the sample. Trachoma grading was done using the WHO simplified grading system. FINDINGS: A total of 17 016 persons were examined, a response rate of 86.1% of the enumerated population. Prevalence of signs of active trachoma in children aged 1-9 years was: TF=53.7% (95% confidence interval (CI)=52.1-55.3); TI=42.7% (95% CI=41.2-44.2); TF and/or TI=64.1% (95% CI=62.5-65.5). Prevalence of trichiasis (TT) in children aged less than 15 years was 1.2% (95% CI=0.9-1.4), while TT prevalence in persons aged 15 years and above was 9.2% (95% CI=8.6-9.9). Women were more likely to have trichiasis compared to men (odds ratio (OR)=1.57; 95% CI=1.34-1.84). Tentative extrapolation to the states of Eastern Equatoria and Upper Nile estimates that there is a backlog of 178,250 (lower and upper bounds=156,027-205,995) persons requiring surgery and the entire population, estimated to be over 3.9 million, is in need of the SAFE strategy to control blinding trachoma. CONCLUSION: Trachoma is a public health problem in all nine of the study sites surveyed. The unusually high prevalence of active trachoma and TT in children points to the severity of the problem. There is urgent need to implement trachoma control interventions in trachoma endemic regions of southern Sudan. PMID:16462982

  19. Issues of expressed stigma of HIV/AIDS among professionals in Southern Sudan.

    PubMed

    Machine, Edwin M; Ross, Michael W; McCurdy, Sheryl A

    2011-08-01

    HIV-related stigma continues to be a significant barrier to HIV testing, treatment, and care. Understanding the factors that underlie this stigma could help remove barriers to HIV/AIDS intervention. We identified these factors among nurses as well as community leaders in Lui, Southern Sudan. Participants included health workers at a local hospital, a women's group, local market traders, religious leaders, and teachers. We categorized the responses generated from group interaction forums as concerns, fears, and perceptions. We found that stigma persisted not only toward people with conspicuous signs of full-blown AIDS, but also toward community programs, like voluntary counseling and testing centers. Future interventions, including delabeling the counseling and testing centers and demonstrating the efficacy of highly active antiretroviral therapy, will be critical in reducing the stigma of HIV/AIDS in communities. PMID:21149851

  20. Lessons learned from translators and interpreters from the Dinka tribe of southern Sudan.

    PubMed

    Baird, Martha B

    2011-04-01

    This article discusses the methodological challenges associated with working with translators and interpreters from the Dinka tribe of southern Sudan during an ethnographic study with refugee Dinka women who were resettled with their children in the United States. Navigating the cultural differences between the researcher, the translator, and the interpreters provided a deeper understanding about the culture of the study population. The lessons learned included the importance of cultural congruence between the interpreters and participants; the education, training, and experience of the interpreters; and the difficulties encountered in preparing interpreters according to university institutional review board requirements. Cultural differences such as time perception and communication and literacy styles were negotiated throughout each phase of the study. The most valuable lesson learned from this experience was the importance of the relationship between the researcher, the translator, and the interpreters as well as between the interpreters and participants to achieve credibility and trustworthiness of the study results. PMID:21317404

  1. Malaria Epidemics and Interventions, Kenya, Burundi, Southern Sudan, and Ethiopia, 1999–2004

    PubMed Central

    Cox, Jonathan; Balkan, Suna; Tamrat, Abiy; Priotto, Gerardo; Alberti, Kathryn P.; Zurovac, Dejan; Guthmann, Jean-Paul

    2006-01-01

    Quantitative data on the onset and evolution of malaria epidemics are scarce. We review case studies from recent African Plasmodium falciparum epidemics (Kisii and Gucha Districts, Kenya, 1999; Kayanza Province, Burundi, 2000–2001; Aweil East, southern Sudan, 2003; Gutten and Damot Gale, Ethiopia, 2003–2004). We highlight possible epidemic risk factors and review delays in epidemic detection and response (up to 20 weeks), essentially due to poor case reporting and analysis or low use of public facilities. Epidemics lasted 15–36 weeks, and patients' age profiles suggested departures from classical notions of epidemic malaria everywhere but Burundi. Although emergency interventions were mounted to expand inpatient and outpatient treatment access, we believe their effects were lessened because of delays, insufficient evaluation of disease burden, lack of evidence on how to increase treatment coverage in emergencies, and use of ineffective drugs. PMID:17176560

  2. Visceral leishmaniasis in southern Sudan: status of healthy villagers in epidemic conditions.

    PubMed

    Seaman, J; Ashford, R W; Schorscher, J; Dereure, J

    1992-10-01

    A combination of interview, serology and skin testing was used to investigate the status of apparently healthy villagers during a visceral leishmaniasis epidemic in southern Sudan. The number of people who had died equalled the number who were alive at the time of the survey. The direct agglutination test (DAT) identified 10% of the people as being serologically positive. Most young children (36/39) and 34% (22/64) of adults had neither positive serology nor skin test. About 64% (42/66) of adults had positive skin tests. In two villages, 54% and 76% of those over four years of age showed evidence of having been infected. The mortality associated with infection was estimated as at least 69%; 25% of those infected appeared to have cured spontaneously. The outcome for the remaining 6% was still doubtful. Even in this devastating epidemic there is, therefore, evidence of a considerable amount of infection without severe disease. Serological tests, while useful clinically, are apparently not useful for detecting early cases. Combined skin testing and serology produces a comprehensive though partially hypothetical picture. PMID:1288429

  3. Structural development and crustal stretching in the Muglad Basin, southern Sudan

    NASA Astrophysics Data System (ADS)

    Mohamed, A. Y.; Ashcroft, W. A.; Whiteman, A. J.

    2001-02-01

    A simplified model cross-section has been established from integrated well data, reflection seismic and gravity data along a northeast-southwest profile in the Unity-Kaikang area in the Muglad Basin, southern Sudan. A multi-layer crustal model has been created to produce a better estimate of the crustal extension involved and assess some of the key factors in the basin's formation by comparison to a theoretical model. Within the sedimentary section, three reflection seismic horizons were picked and their depths were calculated: Top Bentiu (Cenomanian), Top Abu Gabra (Aptian-Albian) and Top Basement (Late Jurassic-Early Cretaceous). The integrated well and seismic data indicate a sedimentary section up to 11 km thick along the cross-section. Different densities were assigned to the three sedimentary layers according to well data, and upper and lower crustal layers were incorporated in the model. Isostatic compensation of the sedimentary fill and the resultant crustal thinning was estimated by gravity modelling. The stretching of the lithosphere is estimated at ≈56 km (≈61%), corresponding to a β factor of 1.61. The form of the basin agrees with the model of a rift basin developed over an extended period of time.

  4. Ebola virus disease in southern Sudan: hospital dissemination and intrafamilial spread

    PubMed Central

    Baron, Roy C.; McCormick, Joseph B.; Zubeir, Osman A.

    1983-01-01

    Between 31 July and 6 October 1979, 34 cases of Ebola virus disease (22 of which were fatal) occurred among five families in a rural district of southern Sudan; the disease was introduced into four of the families from a local hospital. Chains of secondary spread within the family units, accounting for 29 cases resulted from direct physical contact with an infected person. Among all persons with such contact in the family setting, those who provided nursing care had a 5.1-fold increased risk of infection, emphasizing the importance of intimate contact in the spread of this disease. The absence of illness among persons who were exposed to cases in confined spaces, but without physical contact, confirmed previous impressions that there is no risk of airborne transmission. While the ecology of Ebola virus is unknown, the presence of anti-Ebola antibodies in the sera of 18% of persons who were unassociated with the outbreak suggests that the region is an endemic focus of Ebola virus activity. PMID:6370486

  5. Integrated Surveys of Neglected Tropical Diseases in Southern Sudan: How Much Do They Cost and Can They Be Refined?

    PubMed Central

    Kolaczinski, Jan H.; Hanson, Kara; Robinson, Emily; Picon, Diana; Sabasio, Anthony; Mpakateni, Martin; Lado, Mounir; Moore, Stephen; Petty, Nora; Brooker, Simon

    2010-01-01

    Background Increasing emphasis on integrated control of neglected tropical diseases (NTDs) requires identification of co-endemic areas. Integrated surveys for lymphatic filariasis (LF), schistosomiasis and soil-transmitted helminth (STH) infection have been recommended for this purpose. Integrated survey designs inevitably involve balancing the costs of surveys against accuracy of classifying areas for treatment, so-called implementation units (IUs). This requires an understanding of the main cost drivers and of how operating procedures may affect both cost and accuracy of surveys. Here we report a detailed cost analysis of the first round of integrated NTD surveys in Southern Sudan. Methods and Findings Financial and economic costs were estimated from financial expenditure records and interviews with survey staff using an ingredients approach. The main outcome was cost per IU surveyed. Uncertain variables were subjected to univariate sensitivity analysis and the effects of modifying standard operating procedures were explored. The average economic cost per IU surveyed was USD 40,206 or USD 9,573, depending on the size of the IU. The major cost drivers were two key categories of recurrent costs: i) survey consumables, and ii) personnel. Conclusion The cost of integrated surveys in Southern Sudan could be reduced by surveying larger administrative areas for LF. If this approach was taken, the estimated economic cost of completing LF, schistosomiasis and STH mapping in Southern Sudan would amount to USD 1.6 million. The methodological detail and costing template provided here could be used to generate cost estimates in other settings and readily compare these to the present study, and may help budget for integrated and single NTDs surveys elsewhere. PMID:20644619

  6. They Own This: Mother Tongue Instruction for Indigenous Kuku Children in Southern Sudan

    ERIC Educational Resources Information Center

    Laguarda, Ana Isabel; Woodward, Walter Pierce

    2013-01-01

    This article details a pilot program of mother tongue instruction in five primary schools for classes one through three, in Kajokeji County, Central Equatoria State, South Sudan. The program was launched by teachers and volunteers with the support of the Jesuit Refugee Service, an international non-governmental organization. The research examines…

  7. Obstetric fistula in Southern Sudan: situational analysis and Key Informant Method to estimate prevalence

    PubMed Central

    2013-01-01

    Background Obstetric fistula is a severe condition which can have devastating consequences for a woman’s life. Despite a considerable literature, very little is known about its prevalence. This project was conducted to carry out a situational analysis of fistula services in South Sudan and to pilot test the Key Informant Method (KIM) to estimate the prevalence of fistula in a region of South Sudan. Methods Key stakeholder interviews, document reviews and fistula surgery record reviews were undertaken. A KIM survey was conducted in a district of Western Bahr-el-Ghazal in January 2012. One hundred sixty-six community-based distributors, traditional birth attendants and village midwives were trained as key informants to identify women with fistula in the community. Women identified were subsequently examined by an obstetrician and nurse to verify whether they had a fistula. Results There were limited fistula repair services in South Sudan. Approximately 50–80 women per year attend periodic campaigns, with around half having a fistula and receiving a repair. On average a further 5 women a year received fistula repair from hospital services. Ten women with potential fistula were identified via KIM; all confirmed by the obstetrician. Of these, three were from the survey area, which had 8,865 women of reproductive age (15–49 years). This gives a minimal estimated prevalence of at least 30 fistulas per 100,000 women of reproductive age (95% CI 10–100). Conclusions Routine fistula repair services available do not meet the population’s needs. The pilot study suggests that KIM can be used to identify women with fistula in the community. Data on fistula are generally poor; the KIM methodology we used in South Sudan yielded a lower fistula prevalence than estimates reported previously in the region. PMID:23497241

  8. Schistosomiasis and soil-transmitted helminths among an adult population in a war affected area, Southern Kordofan state, Sudan

    PubMed Central

    2012-01-01

    Background Schistosomiasis remains a major health problem at global and national levels, contributing to the vulnerability of the poor people in Sudan. Southern Kordofan is affected by Schistosomiasis but the disease prevalence was unknown. Methods 1826 adults were recruited in a community-based survey. Each recruited subject submitted at least 10 ml urine and one stool sample; they were also interviewed and filled in a questionnaire. Results 1826 adults were recruited in a community-based survey. Each recruited subject submitted at least 10 ml urine and one stool sample; they were also interviewed and filled in a questionnaire. The prevalence of S. haematobium was 6.9 % among the adult population. We estimated S. mansoni prevalence as 0.0 %. S. haematobium infection was focally distributed at the village level. The infection was associated with non preference of latrine use – if available, use of open water source for household affairs such as cleaning and also with the history of schistosomiasis treatment. The prevalence of soil transmitted helminths (STH) was also reported as high at 7.8 %, and two species were identified; Hymenolepis nana and Giardia lamblia. Conclusion Schistosomiasis is a significant health problem among the adult population in Southern Kordofan. The estimated prevalence will serve as a guide in developing a Schistosomiasis Control Program and applying treatment plans. PMID:22759923

  9. Soil moisture characteristics and implications for vegetation regeneration in Sudan during the period 1965-2005.

    NASA Astrophysics Data System (ADS)

    El Haj El Tahir, M.; Xu, C.; Zengxin, Z.

    2012-04-01

    This study aims at better understanding the soil moisture (SM) characteristics as fundamental factors for vegetation regeneration in Sudan during the period 1965-2005. The Mann Kendall (MK) analysis was used to test the trend in the average monthly soil moisture (SM), rainfall and temperature data. Geographically weighted regression (GWR) was selected to study the SM, rainfall and temperature relations because it accounts for the local spatial variability and non-stationarity of these variables. To further understand dry and wet variations in terms of regeneration demand, the aridity index (AI) was used. The results of (MK) test showed that there were decreasing trends of SM on an annual and seasonal level and that the trend was less dramatic or softer in the dry season (November-April) than the wet season (May- October). That soil moisture variability followed closely that of rainfall and temperature, although there was a hint that SM variability followed temperature changes more closely than rainfall. The (GWR) model gave optimal results in semi-arid central Sudan. In the north due to lack of rainfall and in the south due to plant heterogeneity, the model did not perform so well. The spatio-temporal variability of the (AI) showed that the long-term average of (AI) was affected by the reported decline in rainfall during 1965-1985. The decadal (AI) average of 1995-2005 gave evidence of increases in rainfall that are reported since the mid-nineties. (AI) performed well in reflecting the wet conditions in Sudan. Very rare are the studies of soil moisture in Sudan, especially in the through way that is presented here.

  10. Sudan, Africa

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Overlooking northwest Sudan (19.5N, 22.5E) toward the southeast, the Sahara Desert stretches to the horizon across this barren landscape where windblown sand has created an elaborate pattern of windstreaks across the scoured surface.

  11. The Birth of a New Nation: The Republic of South Sudan

    ERIC Educational Resources Information Center

    Totten, Samuel

    2011-01-01

    In early July, the country of Sudan, wracked by civil war since the 1980s, officially split into two separate nations, Sudan and South Sudan. Six months earlier, over a seven-day period, the people in southern Sudan had voted in a national referendum on whether to secede from the North. The voters had two choices: "Separation" or "Unity." For the…

  12. High prevalence of hypertension among an ethnic group in Sudan: implications for prevention.

    PubMed

    Noor, Sufian K; Elsugud, Nada A; Bushara, Sarra O; Elmadhoun, Wadie M; Ahmed, Mohamed H

    2016-04-01

    Objective Hypertension is an emerging non-communicable disease in developing countries. Due to its silent nature and serious complications, active screening is essential in order to prevent complications. For instance, premature mortality from cardiovascular diseases could be prevented by the effective control of hypertension. The aim of this study was to determine the prevalence of undiagnosed hypertension among Nuba ethnic group living in Atbara city, north Sudan and to identify the associated risk factors. Subject and methods All consenting 500 adults from Nuba tribe who live in El Wihda District, Atbara were included. Blood pressure (BP) and body mass index were measured. Standard interviewing procedures were used to record medical history, socio-demographic data, and lifestyle characteristics. Results Among the 500 participants, females were 364 (72.8%) and males were 136 (27.2%). The overall prevalence of undiagnosed hypertension was 49.4% (30.8% stage 1 hypertension and 18.6% stage 2 hypertension). In addition, 41% of the population was having prehypertension. The significant risk factors for high BP were: male sex, age above 45 years, overweight, illiteracy, and alcohol consumption. Conclusion Undiagnosed high BP is very common among Nuba ethnic group; therefore, active screening and early management are recommended to prevent complications. PMID:26738696

  13. Food aid and development in southern Sudan: implications of the Comprehensive Peace Agreement for response planning.

    PubMed

    Sharp, Buzz

    2007-03-01

    In the post-Comprehensive Peace Agreement (CPA) era a greater impact on the unacceptably high prevalence of child malnutrition is more likely to come from additional investment and attention to education, health, hygiene, sanitation and childcare practices than from expanded food aid interventions. The negligible impact of food aid on malnutrition, although most commonly challenged on the quality of needs assessments, is equally attributable to the timing of deliveries, and a dysfunctional distribution system. Comparatively few resources have been allocated to strengthen skills for assessing, analysing and understanding community priorities, local economies, and social safety nets. A more thoughtful allocation of scarce funds could have more impact if a range of alternative responses was considered. Participation in and commitment to a more independent livelihoods analytical forum would improve communication with the new government, local leaders and other partners, as well as providing a platform for reaching consensus on both humanitarian and development planning over the next five years. PMID:17349001

  14. Al Jazirah, Sudan

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Al Jazirah (also Gezira) is one of the 26 states of Sudan. The state lies between the Blue Nile and the White Nile in the east-central region of the country. It is a well populated area suitable for agriculture. The area was at the southern end of Nubia and little is known about its ancient history and only limited archaeological work has been conducted in this area. The region has benefited from the Gezira Scheme, a program to foster cotton farming begun in 1925. At that time the Sennar Dam and numerous irrigation canals were built. Al Jazirah became the Sudan's major agricultural region with more than 2.5 million acres (10,000 km) under cultivation. The initial development project was semi-private, but the government nationalized it in 1950. Cotton production increased in the 1970s but by the 1990s increased wheat production has supplanted a third of the land formerly seeded with cotton.

    The image was acquired December 25, 2006, covers an area of 56 x 36.4 km, and is located near 14.5 degrees north latitude, 33.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  15. A climate trend analysis of Sudan

    USGS Publications Warehouse

    Funk, Christopher C.; Eilerts, Gary; Verdin, Jim; Rowland, Jim; Marshall, Michael

    2011-01-01

    Summer rains in western and southern Sudan have declined by 10-20 percent since the mid-1970s. Observed warming of more than 1 degree Celsius is equivalent to another 10-20 percent reduction in rainfall for crops. The warming and drying have impacted southern Darfur and areas around Juba. Rainfall declines west of Juba threaten southern Sudan's future food production prospects. In many cases, areas with changing climate are coincident with zones of substantial conflict, suggesting some degree of association; however, the contribution of climate change to these conflicts is not currently understood. Rapid population growth and the expansion of farming and pastoralism under a more variable climate regime could dramatically increase the number of at-risk people in Sudan over the next 20 years.

  16. The Kordofan earthquakes, central Sudan

    NASA Astrophysics Data System (ADS)

    Clark, R. A.; Browne, S. E.

    Geophysical studies have revealed extensive rift systems throughout Central Africa, among them the White Nile Rift runnng SE-NW across central Sudan. Few earthquakes have been detected teleseismically in areas of Sudan away from the East African or Red Sea Rift systems. Relocations presented here confirm three earthquakes to have occurred at shallow depth at the NW extreme of the White Nile Rift, around Jebel Dumbeir, Kordofan province. Ambiguity in a teleseismic P-wave first-motion solution for the 9 October 1966 0648GMT event is resolved by use of the P/pP/sP relative amplitude method. The fault plane is near-vertical, striking to 005-025° with a downthrow to the SE and a minor sinistral strike-slip component. This is consistent with ground deformation and location of an aftershock. Its downthrow direction appears to reflect subsidence of the White Nile Rift and central Sudan. Its strike is common with present-day activity in the Ethiopian Rift, suggesting that a near ESE-WSW stress regime persists across central and southern Sudan.

  17. Measuring turbidity, and indicator to evaluate drinkability of waters in Southern countries? Approaches from Burkina Faso, Sudan and Argentina case studies

    NASA Astrophysics Data System (ADS)

    Lavie, Emilie; Robert, Elodie

    2013-04-01

    The relationship between proportion of suspended solids, dissolved oxygen and bacteriology has long been proven (Brock, 1966; Lechevallier et al., 1985; Bustina and Levallois, 2003; Chang and Liao, 2012), bacteria need coarse elements to hang on and develop. However, water bacteriology analyses are difficult to implement in southern countries. They are expensive and require sterile equipment, transport in cold conditions and a nearby laboratory, which remains difficult in remote areas under these hot latitudes. Yet, simple measurement devices allow to know in a few minutes the water turbidity. Is turbidity an efficient tool to evaluate the drinkability of water when no bacteriological analyses are possible? The results proposed here are taken from three different studies whose purposes were to measure different physical, chemical and bacteriological parameters of water used for human and/or animal consumption. One of the finalities was to propose a method, at lower cost, to evaluate the drinkability of water for consumption. Four case studies were chosen: the basin of the Doubegue River in Burkina Faso is a rural area of a developing country, where drinking water is taken from the alluvial aquifer close to the surface. Furthermore, the laundry is washed and the children play in running streams. Major expansion of the cultivated lands since 1980s has brought important soils losses, thus a chronicle contamination of surface water with suspended solids (Robert, 2012). The Mendoza and Tunuyán Rivers Basins in Argentina, an emerging country, have snow-glaciar regimes with naturally turbid waters. They supply drinking water to two towns, Mendoza and Tunuyán cities, respectively 1 million and 40,000 inhabitants. However, these two streams -whose watersheds are common- do not present the same managements: the Mendoza River has been equipped with large hydraulic infrastructures, moving the turbid waters into clear and erosive ones (Lavie, 2009), while the Tunuyán River and its tributaries were not transformed upstream our sample points (Lavie et al., 2013, under press). Finally, we studied an urban drinking waters network, in Khartoum, the capital of Sudan, one of the least developed countries, with chronic political crises. The nearly 6 million inhabitants of this settlement suffer many cuts and bad pressure at tap. Furthermore, Nile's waters that feed the network are summarily treated and then quite turbid, especially in summer during Nile's floods. This situation obliges the population to store and to decant water, transforming it into clear ones (Lavie and Hamza, 2013, under press). The results of our studies demonstrate that, generally, we can observe a correlation between increasing turbidity and bacteriology, and decreasing oximetry. This assumption is disproven in many cases: (1) the stagnant waters of Khartoum and (2) the clarified Mendoza River waters. Finally, (3) the seasonal anthropogenic uses of soil and waters in the Doubegue and Tunuyán Rivers have more impact on the bacteriological quality than the natural seasonality of the suspended solids because soil erosion has increased.

  18. Filariasis in the Sudan

    PubMed Central

    Kirk, R.

    1957-01-01

    The author summarizes the available information on Loa loa, Acanthocheilonema perstans and Wuchereria bancrofti infections in the Sudan, with special reference to the prevalence and distribution of the vectors. PMID:13472413

  19. The Southern Ocean "superbloom" of 2000: implications for carbon cycling

    NASA Astrophysics Data System (ADS)

    Kahru, M.; Mitchell, B.

    2005-12-01

    During the austral spring bloom in January-February, 2000 the concentration of surface chlorophyll-a (Chl) in the Southern Ocean was higher than the long-term average based on the 1997-2005 ocean color data. Chlorophyll anomalies were not uniformly distributed as areas with 3-4 times higher Chl were interspersed with areas of up to 3-4 times lower than the long-term mean. In general, Chl was nearly 50% higher in the Indian, Atlantic and Western Pacific sectors south of 60S but about normal in Western Pacific. All sectors south of 60S had also colder than normal sea-surface temperature (SST). Export flux of carbon calculated according to the model of Laws (2004) was almost double for the whole Southern Ocean during early 2000 compared to 1997. The interannual fluctuations in the rate of carbon removal from the euphotic zone should have implications for global carbon cycling and gas exchange. We investigate the relationships between these anomalies and various climatic indices (SOI, the Antarctic Circumpolar Wave), and the potential mechanisms causing the Chl anomalies.

  20. Demanding Divestment from Sudan

    ERIC Educational Resources Information Center

    Asquith, Christina

    2006-01-01

    Bowing to student demands to "stop supporting genocide," the University of California regents voted earlier this year to divest millions of dollars from companies working in the war-torn African nation of Sudan, the first major public university in the nation to take such action. Since student protests on the subject began at Harvard University in

  1. Demanding Divestment from Sudan

    ERIC Educational Resources Information Center

    Asquith, Christina

    2006-01-01

    Bowing to student demands to "stop supporting genocide," the University of California regents voted earlier this year to divest millions of dollars from companies working in the war-torn African nation of Sudan, the first major public university in the nation to take such action. Since student protests on the subject began at Harvard University in…

  2. UNICEF and the Sudan.

    ERIC Educational Resources Information Center

    United Nations Children's Fund, Nairobi (Kenya). Eastern Africa Regional Office.

    Coupled with poor infrastructure, vast distances, and harsh climatic conditions, the enormous physical obstacles in the Sudan (Africa's largest country) have combined to produce extremely serious problems for Sudanese children, who will soon constitute half of the 17 million people there. This booklet describes continuing projects implemented by…

  3. Preliminary survey of ticks (Acari: Ixodidae) on cattle in northern Sudan.

    PubMed

    Salih, D A; Hassan, S M; El Hussein, A M; Jongejan, F

    2004-12-01

    In a cross sectional survey conducted during the period June 2001 to July 2002, the geographical distribution of ticks on cattle in the Sudan was determined. Seventeen locations were surveyed from Northern, Central, Eastern, Western, Blue Nile and White Nile Provinces. Total body collections of ticks were made from 20 cattle at each location. Four tick genera and 11 species were identified. The tick species collected included Amblyomma lepidum, Amblyomma variegatum, Boophilus decoloratus, Hyalomma anatolicum anatolicum, Hyalomma dromedarii, Hyalomma impeltatum, Hyalomma marginatum rufipes, Hyalomma truncatum, Rhipicephalus evertsi evertsi, Rhipicephalus sanguineus group and Rhipicephalus simus simus. Major ecological changes have occurred due to extensive animal movement, deforestation, desertification and establishment of large mechanized agricultural schemes. These factors have certainly affected the distribution of ticks and tick-borne diseases in the Sudan. The absence of A. variegatum and A. lepidum in northern Sudan was not surprising, since these tick species are known to survive in humid areas and not in the desert and semi-desert areas of northern Sudan. The absence of B. annulatus in northern and central Sudan is in accordance with the finding that this tick species is restricted to the southern parts of the central Sudan. The presence of H. anatolicum anatolicum in Um Benin in relatively high abundance is an interesting finding. The present finding may indicate that the southern limit of this species has changed and moved southwards to latitude 13 degrees N. It is concluded that major changes in tick distribution have taken place in the Sudan. PMID:15732459

  4. Vitamin A deficiency in the Sudan: a call for a surveillance system.

    PubMed

    el Bushra, H E

    1992-05-01

    This short review summarizes all the published and unpublished reports on vitamin A deficiency in the Sudan in the last four decades. Different local terms used by people to indicate vitamin A deficiency were enlisted. There is evidence that vitamin A deficiency is a public health problem in eastern Sudan and among communities from western and southern Sudan living around Greater Khartoum, who were displaced from their homelands because of drought, famine conditions and civil unrest. There are reports indicative of vitamin A deficiency problem in the central and the far western provinces. There were no reports from the northern provinces. The need for a surveillance system was discussed. PMID:1644048

  5. [Sudan, through the back door].

    PubMed

    Veeken, H

    1998-08-01

    South Sudan has five million inhabitants and has been fighting a war of independence with North Sudan since 1959. The hostilities have totally disrupted society and the country is the most inaccessible of Africa. International non-government organizations co-operate in relief activities in the 'Operation Life Line'. Semi-nomadic pastoral tribes populate South Sudan. Doctors Without Borders assisted in fighting a major epidemic of kala azar in the late eighties which cost some 200,000 lives; the organization still provides medical aid in the country. PMID:9856145

  6. The Southern Survey of Agricultural Majors: Some Implications for the Future of Higher Education in Agriculture.

    ERIC Educational Resources Information Center

    Cosby, Arthur G.

    Some implications of the Southern Survey of Agricultural Majors for the training of agricultural professionals are examined. Women agricultural majors were found to be playing a role in the recent growth in enrollment. Females were found to be less likely than male students to have parents who own farms. It is claimed that agricultural education…

  7. Prevalence of Trachoma in Unity State, South Sudan: Results from a Large-Scale Population-Based Survey and Potential Implications for Further Surveys

    PubMed Central

    Edwards, Tansy; Smith, Jennifer; Sturrock, Hugh J. W.; Kur, Lucia W.; Sabasio, Anthony; Finn, Timothy P.; Lado, Mounir; Haddad, Danny; Kolaczinski, Jan H.

    2012-01-01

    Background Large parts of South Sudan are thought to be trachoma-endemic but baseline data are limited. This study aimed to estimate prevalence for planning trachoma interventions in Unity State, to identify risk factors and to investigate the effect of different sampling approaches on study conclusions. Methods and Findings The survey area was defined as one domain of eight counties in Unity State. Across the area, 40 clusters (villages) were randomly selected proportional to the county population size in a population-based prevalence survey. The simplified grading scheme was used to classify clinical signs of trachoma. The unadjusted prevalence of trachoma inflammation-follicular (TF) in children aged 1–9 years was 70.5% (95% CI: 68.6–72.3). After adjusting for age, sex, county and clustering of cases at household and village level the prevalence was 71.0% (95% CI: 69.9–72.1). The prevalence of trachomatous trichiasis (TT) in adults was 15.1% (95% CI: 13.4–17.0) and 13.5% (95% CI: 12.0–15.1) before and after adjustment, respectively. We estimate that 700,000 people (the entire population of Unity State) require antibiotic treatment and approximately 54,178 people require TT surgery. Risk factor analyses confirmed child-level associations with TF and highlighted that older adults living in poverty are at higher risk of TT. Conditional simulations, testing the alternatives of sampling 20 or 60 villages over the same area, indicated that sampling of only 20 villages would have provided an acceptable level of precision for state-level prevalence estimation to inform intervention decisions in this hyperendemic setting. Conclusion Trachoma poses an enormous burden on the population of Unity State. Comprehensive control is urgently required to avoid preventable blindness and should be initiated across the state now. In other parts of South Sudan suspected to be highly trachoma endemic, counties should be combined into larger survey areas to generate the baseline data required to initiate interventions. PMID:22506082

  8. Seismic Hazard Implication of the Seismotectonics of southern Africa

    NASA Astrophysics Data System (ADS)

    Midzi, Vunganai; Mulabisana, Thifelimbilu; Manzunzu, Brassnavy

    2014-05-01

    The work presented in this report / presentation was prepared as part of the requirements for the SIDA/IGCP Project 601 titled "Seismotectonics and Seismic Hazards in Africa" as well as part of the seismic source characterisation of the GEM-Africa Seismic hazard study. An effort was made to compile information necessary to prepare a seismotectonic map of Africa which can then be used in carrying out a seismic hazard assessment of the continent or locations within the continent. Information on major faults, fault plane solutions, geophysical data as well as stress data has so far been collected and included in a database for the southern Africa region. Reports published by several experts contributed much to the collected information. The seismicity data used are part of the earthquake catalogue being prepared for the GEM-Africa project, which includes historical and instrumental records as collected from various sources. An effort has been made to characterise the identified major faults and through further analysis investigate their possible impact on the seismic hazard of southern Africa.

  9. Plasmodium falciparum population structure in Sudan post artemisinin-based combination therapy.

    PubMed

    Bakhiet, Amani M A; Abdel-Muhsin, Abdel-Muhsin A; Elzaki, Salah-Eldin G; Al-Hashami, Zainab; Albarwani, Hamida S; AlQamashoui, Badar A; Al-Hamidhi, Salama; Idris, Mohamed A; Elagib, Atif A; Beja-Pereira, Albano; Babiker, Hamza A

    2015-08-01

    Over the past decade, Sudan has stepped up malaria control backed by WHO, and this has resulted in significant reduction in parasite rate, malaria morbidity and mortality. The present study analyzed Plasmodium falciparum parasites in four geographical separated areas, to examine whether the success in malaria control following the use of artemisinin-based combination therapy (ACT) has disrupted the population structure and evolution of the parasite. We examined 319 P. falciparum isolates collected between October 2009 and October 2012 in four different areas in Sudan (Jazira [central Sudan], Southern Darfur [western Sudan], Upper Nile [southern Sudan] and Kasala [eastern Sudan]). Twelve microsatellites were analyzed for allelic diversity, multi-locus haplotype and inter-population differentiation. Level of diversity was compared to that detected for three of the above microsatellites among P. falciparum parasites in central and eastern Sudan in 1999, prior to introduction of ACT. Diversity at each locus (unbiased heterozygosity [H]) was high in all areas (Jazira, H=0.67), (Southern Darfur, H=0.71), (Upper Nile, H=0.71), and (Kasala, H=0.63). Microsatellites were distributed widely and private alleles, detected in a single population, were rare. The extent of diversity in the above sites was similar to that seen, in 1999, in central (Khartoum, H=0.73) and eastern Sudan (Gedaref, H=0.75). Significant Linkage disequilibrium (LD) was observed between the microsatellites in all populations. Pairwise FST analysis revealed that parasites in the four areas could be considered as one population. However, the parasites in Sudan clustered away from parasites in West Africa and the Arabian Peninsula. Despite marked reduction in malaria risk in Sudan, the extent of diversity and parasite genetic structure are indicative of a large population size. Further considerable reduction in transmission would be needed before fragmented sub-population can be seen. In addition, the large divergence of P. falciparum in Sudan from West Africa and Arabian Peninsula populations may result from differential evolutionary pressures acting at the population level, which shall be considered in eradication plans. PMID:25913735

  10. [Onchocerciasis in Sudan: epidemiological situation in the south-west].

    PubMed

    Ibrahim, A A

    1987-01-01

    Human onchocerciasis is found along the Nile in Northern Sudan, on the border with Ethiopia and in the Southern and Western Sudan--all areas where there is fast flowing water suitable for S. damnosum S.L. (in Sudan, the only fly in which the O. volvulus has been found) to breed. Epidemiological studies of this disease are still in progress however it is clear that in the huge area between Bahr El-Arabe and the white Nile, which is the most serious focus with blindness rates equalling or exceeding those in the worst affected foci elsewhere in Africa. Infection rates and parasite populations are highest in villages situated on rivers--near the probable breeding sites. Intensity of infection is generally highest in skin snip taken from the pelvi region, where the palpable nodules are more frequent. Microfilariae are commonly detected in the anterior chamber of the eye and in the peripheral blood. Fundus oculi lesions have been also detected in significant numbers causing impairment of vision and blindness, specially in the group of old people. Males are more commonly infected than females. These data provide a reasonable, though far from complete, account of the present situation concerning the importance and severity of onchocerciasis in this part of Sudan. PMID:3431381

  11. Geology and geophysics of the West Nubian Paleolake and the Northern Darfur Megalake (WNPL-NDML): Implication for groundwater resources in Darfur, northwestern Sudan

    NASA Astrophysics Data System (ADS)

    Elsheikh, Ahmed; Abdelsalam, Mohamed G.; Mickus, Kevin

    2011-08-01

    The recent delineation of a vastly expanded Holocene paleo-lake (the Northern Darfur Megalake which was originally mapped as the West Nubian Paleolake and here will be referred to as WNPL-NDML) in Darfur in northwestern Sudan has renewed hopes for the presence of an appreciable groundwater resource in this hyper-arid region of Eastern Sahara. This paleolake which existed within a closed basin paleo-drainage system might have allowed for the collection of surface water which was subsequently infiltrated to recharge the Paleozoic-Mesozoic Nubian Aquifer. However, the presence of surface exposures of Precambrian crystalline rocks in the vicinity of the paleolake has been taken as indicating the absence of a thick Paleozoic-Mesozoic sedimentary section capable of holding any meaningful quantity of groundwater. This work integrates surface geology and gravity data to show that WNPL-NDML is underlain by NE-trending grabens forming potential local Paleozoic-Mesozoic aquifers that can hold as much as 1120 km 3 of groundwater if the sedimentary rocks are completely saturated. Nevertheless, it is advised here that recharge of the Nubian aquifer under WNPL-NDML is insignificant and that much of the groundwater is fossil water which was accumulated during different geological times much wetter than today's hyper-arid climate in Eastern Sahara. Excessive extraction will lead to quick depletion of this groundwater resource. This will result in lowering of the water table which in turn might lead to the drying out of the oases in the region which provide important habitats for humans, animals and plants in northern Darfur.

  12. Southern Hemisphere Storm Zones on Mars: Implications of MOLA Topography

    NASA Technical Reports Server (NTRS)

    Hollingsworth, J. L.; Haberle, R. M.; Schaeffer, J.

    1999-01-01

    Using the NASA Ames Mars general circulation model and recent Mars orbiter laser altimeter (MOLA) global topography, annual-cycle simulations have been performed corresponding to a lowglobally-averaged atmospheric dust loading (tau= 0 - 3). Comparisons of key global circulation fields as simulated utilizing previous topography datasets and those using the new Mars global topography have been carried out. Values of globally and/or hemispheric averaged kinetic energy associated with the longitudinally averaged (i.e., zonal) circulation and longitudinal departures (i.e., eddy components) as a function of season for simulations using the different topography datasets are provided contributions arising frommeteorological variability associated with thermal tides, stationary circulation components and recurrent weather systems (transient baroclinc and/or barotropic eddies). It can be noted that eddy activity in the northern hemisphere (NH) is substantially diminished using the new topographic data, and that at some seasons, the southern hemisphere (SH) activity is moderately increased. Additional information is contained in the original extended abstract.

  13. Tectonic implications of Thermopolis anticline, southern Big Horn basin, Wyoming

    SciTech Connect

    Paylor, E.D.; Muncy, H.L.; Lang, H.R.; Conel, J.E.; Adams, S.L.

    1987-08-01

    Surface geology interpreted from 1:24,000 scale Landsat Thematic Mapper images, in combination with topographic, borehole, seismic reflection, and field data were used to analyze the structure of the Thermopolis anticline, a Laramide Foreland structure in the southern Big Horn basin, Wyoming. Their results demonstrate that the anticline is asymmetric and verges to the southwest, away from the basin axis. Subsurface fold geometry can be predicted in cross section using a concentric fold model constrained by surface geology and balanced by bed-length measurements. The steep southwest limb is cut by multiple northeast-dipping thrust faults that thin the stratigraphic sequence approximately 25%. In the footwall, beds are upturned against the fault zone providing structural closure and a possible exploration target. Northeast-trending compartmental faults cut both the hanging wall and footwall, and segment the anticline into blocks that deformed independently from one another. Northeast-trending, low-amplitude folds are superimposed on the anticline. Flexural-slip folding, thrust faulting, and conjugate faulting were dominant mechanisms operating on the sedimentary sequence during deformation by compression. Seismic reflection data confirms predictions of subsurface geometry and indicate three stages of fault/fold development: (a) thrusting, initial brittle basement failure at low angles; (b) fold development, thrust fault propagation through the stratigraphic sequence inducing folding in sedimentary strata and cataclasis in subjacent crystalline basement; and (c) back-limb thrusting, culmination of fold development by backlimb thrusting of sedimentary strata. Structural geometry is consistent with either: (1) multiple phases of Laramide compression, or (2) a single phase of Laramide compression with shear-zone deformation.

  14. Spatial and temporal distribution of the malaria mosquito Anopheles arabiensis in northern Sudan: influence of environmental factors and implications for vector control

    PubMed Central

    Ageep, Tellal B; Cox, Jonathan; Hassan, M'oawia M; Knols, Bart GJ; Benedict, Mark Q; Malcolm, Colin A; Babiker, Ahmed; El Sayed, Badria B

    2009-01-01

    Background Malaria is an important public health problem in northern Sudan, but little is known about the dynamics of its transmission. Given the characteristic low densities of Anopheles arabiensis and the difficult terrain in this area, future vector control strategies are likely to be based on area-wide integrated pest management (AW-IPM) that may include the sterile insect technique (SIT). To support the planning and implementation of future AW-IPM activities, larval surveys were carried out to provide key data on spatial and seasonal dynamics of local vector populations. Methods Monthly cross-sectional larval surveys were carried out between March 2005 and May 2007 in two localities (Dongola and Merowe) adjacent to the river Nile. A stratified random sampling strategy based on the use of Remote Sensing (RS), Geographical Information Systems (GIS) and the Global Positioning System (GPS) was used to select survey locations. Breeding sites were mapped using GPS and data on larval density and breeding site characteristics were recorded using handheld computers. Bivariate and multivariate logistic regression models were used to identify breeding site characteristics associated with increased risk of presence of larvae. Seasonal patterns in the proportion of breeding sites positive for larvae were compared visually to contemporaneous data on climate and river height. Results Of a total of 3,349 aquatic habitats sampled, 321 (9.6%) contained An. arabiensis larvae. The frequency with which larvae were found varied markedly by habitat type. Although most positive sites were associated with temporary standing water around the margins of the main Nile channel, larvae were also found at brickworks and in areas of leaking pipes and canals – often far from the river. Close to the Nile channel, a distinct seasonal pattern in larval populations was evident and appeared to be linked to the rise and fall of the river level. These patterns were not evident in vector populations breeding in artificial water sources away from the river. Conclusion The GIS-based survey strategy developed in this study provides key data on the population dynamics of An. arabiensis in Northern State. Quantitative estimates of the contributions of various habitat types and their proximity to settlements provide a basis for planning a strategy for reducing malaria risk by elimination of the vector population. PMID:19500425

  15. Leishmaniasis in Sudan. Visceral leishmaniasis.

    PubMed

    Zijlstra, E E; el-Hassan, A M

    2001-04-01

    From the early 1900s, visceral leishmaniasis (VL; kala-azar) has been among the most important health problems in Sudan, particularly in the main endemic area in the eastern and central regions. Several major epidemics have occurred, the most recent--in Western Upper Nile province in southern Sudan, detected in 1988--claiming over 100,000 lives. The disease spread to other areas that were previously not known to be endemic for VL. A major upsurge in the number of cases was noted in the endemic area. These events triggered renewed interest in the disease. Epidemiological and entomological studies confirmed Phlebotomus orientalis as the vector in several parts of the country, typically associated with Acacia seyal and Balanites aegyptiaca vegetation. Infection rates with Leishmania were high, but subject to seasonal variation, as were the numbers of sand flies. Parasites isolated from humans and sand flies belonged to three zymodemes (MON-18, MON-30 and MON-82), which all belong to the L. donovani sensu lato cluster. Transmission dynamics have not been elucidated fully; heavy transmission in relatively scarcely populated areas such as Dinder national park suggested zoonotic transmission whereas the large numbers of patients with post kala-azar dermal leishmaniasis (PKDL) in heavily affected villages may indicate a human reservoir and anthroponotic transmission. Clinical presentation in adults and in children did not differ significantly, except that children were more anaemic. Fever, weight loss, hepato-splenomegaly and lymphadenopathy were the most common findings. PKDL was much more common than expected (56% of patients with VL developed PKDL), but other post-VL manifestations were also found affecting the eyes (uveitis, conjunctivitis, blepharitis), nasal and/or oral mucosa. Evaluation of diagnostic methods showed that parasitological diagnosis should still be the mainstay in diagnosis, with sensitivities for lymph node, bone marrow and spleen aspirates of 58%, 70% and 96%, respectively. Simple, cheap serological tests are needed. The direct agglutination test (DAT) had a sensitivity of 72%, specificity of 94%, positive predictive value of 78% and negative predictive value of 92%. As with other serological tests, the DAT cannot distinguish between active disease, subclinical infection or past infection. The introduction of freeze-dried antigen and control sera greatly improved the practicality and accuracy of the DAT in the field. An enzyme-linked immunosorbent assay using recombinant K39 antigen had higher sensitivity than DAT (93%). The polymerase chain reaction using peripheral blood gave a sensitivity of 70-93% and was more sensitive than microscopy of lymph node or bone marrow aspirates in patients with suspected VL. The leishmanin skin test (LST) was typically negative during active VL and converted to positive in c. 80% of patients 6 months after treatment. Immunological studies showed that both Th1 and Th2 cell responses could be demonstrated in lymph nodes from VL patients as evidenced by the presence of messenger ribonucleic acid for interleukin (IL)-10, interferon gamma and IL-2. Treatment of peripheral blood mononuclear cells from VL patients with IL-12 was found to drive the immune response toward a Th1 type response with the production of interferon gamma, indicating a potential therapeutic role for IL-12. VL responded well to treatment with sodium stibogluconate, which is still the first line drug at a dose of 20 mg/kg intravenously or intramuscularly per day for 15-30 d. Side effects and resistance were rare. Liposomal amphotericin B was effective, with few side effects. Control measures have not been implemented. Based on observations that VL does not occur in individuals who have a positive LST, probably because of previous cutaneous leishmaniasis, a vaccine containing heat-killed L. major promastigotes is currently undergoing a phase III trial. PMID:11370250

  16. Alkaline ring complexes in Sudan

    NASA Astrophysics Data System (ADS)

    Vail, J. R.

    An anorogenic petrographic province containing nearly 100 alkaline ring complexes extends across Sudan. These anorogenic complexes are distinct from late-orogenic granite-gabbro, calcalkaline plutonic centres particularly in the eastern part of Sudan, many of which also take the form of ring complexes. The biggest, most closely spaces, and most numerous ring complexes occur in a discontinuous belt of alkali granites and syenites, rarer foid syenites, and associated extrusive trachytes, rhyolites and ignimbrites exposed intermittently across 100 km from the Bayuda Desert and Nile River Valley near Khartoum to northern Kordofan Province and the Nuba Mountains region of central Sudan. These complexes range in age from Ordovician to Jurassic, but show no progressive change in age or distribution pattern other than a tendency to align locally in NW-trending bands, which might reflect zones of weakness in the underlying basement rocks. Mesozoic syenites and alkali granites forming plugs and ring complexes lie in a belt parallel to the coast in the Red Sea Hills of eastern Sudan. In the north-west of the country, alkali granites and foid syenites of Tertiary age crop out in the basement inlier of J. Uweinat, and Mesozoic granites, syenites and foid syenites form igneous plutons in Equatoria Province in the extreme south.

  17. Agricultural fields, Khartoum, Sudan, Africa

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This herringbone pattern of irrigated agricultural fields near Khartoum, Sudan (14.5N, 33.5E) is very distinctive in both size and shape. The region contains thousands of these rectangular fields bounded by canals which carry water from both the White and Blue Nile Rivers. A crop rotation system is used so that some fields are in cotton, millit, sorghum or fallow to conserve moisture and control weeds and insects. See also STS049-96-003.

  18. Nile River, Khartoum, Sudan, Africa

    NASA Technical Reports Server (NTRS)

    1983-01-01

    This view shows the confluence of the White Nile and the Blue Nile rivers to form the Nile River at Khartoum, the capital city of Sudan (15.5N, 32.5E). The White Nile comes from the south and drains the Sudd swamp and African Rift Valley while the Blue Nile comes from the southeast draining the Ethiopian highlands. The herringbone field patterns to the south of the city are agricultural fields where cotton is the main crop.

  19. Language Situation in Post-War Sudan

    ERIC Educational Resources Information Center

    Siddiek, Ahmed Gumaa

    2010-01-01

    The theme behind this paper is to review the language policy and language planning in the Sudan, after the institutionalization of peace; by exploring the recent policy of political factions in the North and the South towards languages in post-war Sudan. This effort aims at encouraging non-Arabic speaking-ethnic-groups to accept the Arabic…

  20. Identification of two distinct fire regimes in Southern California: implications for economic impact and future change

    NASA Astrophysics Data System (ADS)

    Jin, Yufang; Goulden, Michael L.; Faivre, Nicolas; Veraverbeke, Sander; Sun, Fengpeng; Hall, Alex; Hand, Michael S.; Hook, Simon; Randerson, James T.

    2015-09-01

    The area burned by Southern California wildfires has increased in recent decades, with implications for human health, infrastructure, and ecosystem management. Meteorology and fuel structure are universally recognized controllers of wildfire, but their relative importance, and hence the efficacy of abatement and suppression efforts, remains controversial. Southern California’s wildfires can be partitioned by meteorology: fires typically occur either during Santa Ana winds (SA fires) in October through April, or warm and dry periods in June through September (non-SA fires). Previous work has not quantitatively distinguished between these fire regimes when assessing economic impacts or climate change influence. Here we separate five decades of fire perimeters into those coinciding with and without SA winds. The two fire types contributed almost equally to burned area, yet SA fires were responsible for 80% of cumulative 1990-2009 economic losses (3.1 Billion). The damage disparity was driven by fire characteristics: SA fires spread three times faster, occurred closer to urban areas, and burned into areas with greater housing values. Non-SA fires were comparatively more sensitive to age-dependent fuels, often occurred in higher elevation forests, lasted for extended periods, and accounted for 70% of total suppression costs. An improved distinction of fire type has implications for future projections and management. The area burned in non-SA fires is projected to increase 77% (±43%) by the mid-21st century with warmer and drier summers, and the SA area burned is projected to increase 64% (±76%), underscoring the need to evaluate the allocation and effectiveness of suppression investments.

  1. Gravity study of the White Nile Rift, Sudan, and its regional tectonic setting

    NASA Astrophysics Data System (ADS)

    Browne, S. E.; Fairhead, J. D.; Mohamed, I. I.

    1985-03-01

    A compilation of 675 Bouguer gravity values for central Sudan show the presence of a series of linked gravity minima of approximately 40 km width and amplitude 200-300 g.u. to the east and north of the Nuba Mountains. These anomalies are interpreted as delineating the low-density sedimentary infill of the White Nile Rift. A broader 150 km wide positive Bouguer anomaly of amplitude less than 300 g.u. is centred over the Rift in the southern part of the study area and is interpreted in terms of a thinned crust beneath the Rift. Such a model is consistent with the subsidence nature of the Rift. The White Nile Rift is similar in tectonic character to the Southern Sudan Rift and the Blue Nile and Atbara fault controlled basins in that these Cretaceous/Tertiary structures all follow similar structural trends and terminate in line at their northwest end. This termination is considered to be caused by a structural lineament, possibly a shear zone, extending the Central African shear zone through Sudan. The form of the lineament is unknown but is considered to have had a major structural control on the development of deep sedimentary basins in Sudan since Cretaceous times and on the development of the Red Sea.

  2. Sudan challenges the sand dragon.

    PubMed

    Tinker, J

    1978-01-01

    Formerly productive areas have become wasteland as the desert advances in the Sudan. To understand how desertification is undermining the very survival of the Sahel, one ecosystem is reviewed in detail here: the gum arabic zone of Kordofan. After cotton, gum arabic is Sudan's largest export, worth from $14-26 million in recent years. In this zone the ecologically balanced cycle of gum gardens, fire, grain crops, and fallow is now breaking down; the 1968-1973 drought having in many areas delivered the final blow. Because of a growing population, the cultivation period is extended, and the soil becomes impoverished. Overgrazing in the fallow period, and the lopping of gum trees for firewood is producing a low return on the gum trees. Without this gum to harvest for cash, farmers must repeatedly replant their subsistence crops until the land becomes useless sand. The Sudanese have recognized the problem earlier than most, and a number of imaginative and practicable pilot projects are already in use: 1) waterpoint management; 2) construction of firebreaks; 3) land threatened by shifting dunes has been enclosed by stockproof fence and afforested with local trees; and 4) shelter belts have been planted around town perimeters where old gum tree stumps have started to sprout and the grass is reseeding itself. Out of these pilot projects, and with the advice of the U.N. Environment Program, the U.N. Development Program, and FAO, the Sudanese have developed a modest $26 million desert encroachment control and rehabilitation program (DECARP). PMID:12278008

  3. Rift Valley Fever, Sudan, 2007 and 2010

    PubMed Central

    Aradaib, Imadeldin E.; Erickson, Bobbie R.; Elageb, Rehab M.; Khristova, Marina L.; Carroll, Serena A.; Elkhidir, Isam M.; Karsany, Mubarak E.; Karrar, AbdelRahim E.; Elbashir, Mustafa I.

    2013-01-01

    To elucidate whether Rift Valley fever virus (RVFV) diversity in Sudan resulted from multiple introductions or from acquired changes over time from 1 introduction event, we generated complete genome sequences from RVFV strains detected during the 2007 and 2010 outbreaks. Phylogenetic analyses of small, medium, and large RNA segment sequences indicated several genetic RVFV variants were circulating in Sudan, which all grouped into Kenya-1 or Kenya-2 sublineages from the 2006–2008 eastern Africa epizootic. Bayesian analysis of sequence differences estimated that diversity among the 2007 and 2010 Sudan RVFV variants shared a most recent common ancestor circa 1996. The data suggest multiple introductions of RVFV into Sudan as part of sweeping epizootics from eastern Africa. The sequences indicate recent movement of RVFV and support the need for surveillance to recognize when and where RVFV circulates between epidemics, which can make data from prediction tools easier to interpret and preventive measures easier to direct toward high-risk areas. PMID:23347790

  4. Agonistic behaviour in juvenile southern rock lobster, Jasus edwardsii (Decapoda, Palinuridae): implications for developing aquaculture

    PubMed Central

    Carter, Chris G.; Westbury, Heath; Crear, Bradley; Simon, Cedric; Thomas, Craig

    2014-01-01

    Abstract The Southern rock lobster, Jasus edwardsii, is a temperate species of spiny lobster with established well managed fisheries in Australia and New Zealand. It has also been under consideration as a species with aquaculture potential. Agonistic behaviour has important consequences under aquaculture conditions that encompass direct effects, such as damage or death of protagonists, and indirect effects on growth that relate to resource access, principally food and refuge. This study aimed to identify and characterize behaviours and to make a preliminary investigation of their occurrence under tank culture. Juvenile Jasus edwardsii were examined in a flow-through seawater system using a remote video camera system. Twenty-nine behaviours were divided into three sub-groups: aggressive (11), avoidance (6) and others (12). Aggressive behaviours included attacks, pushing, lifting, clasping and carrying an opponent. Avoidance behaviours included moving away in a backwards-, forwards- or side-stepping motion as well as with more vigorous tail flips. These behaviours were components of twelve behavioural groups that described contact, attack and displacement between individuals. Activity was crepuscular with two clear peaks, one in the morning and the other in the evening. The occurrence of behavioural groups was not different between the morning and evening. The frequency of aggressive behaviours was not affected by changes made to stocking density or access to food. The implications of agonistic behaviours are discussed further in relation to developing aquaculture. PMID:25561845

  5. 15 CFR 742.10 - Anti-terrorism: Sudan.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Anti-terrorism: Sudan. 742.10 Section...-CCL BASED CONTROLS § 742.10 Anti-terrorism: Sudan. (a) License requirements. (1) If AT column 1 or AT... ECCN, a license is required for export to Sudan for anti-terrorism purposes. 1 AT column 1 refers...

  6. 15 CFR 742.10 - Anti-terrorism: Sudan.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 2 2011-01-01 2011-01-01 false Anti-terrorism: Sudan. 742.10 Section...-CCL BASED CONTROLS § 742.10 Anti-terrorism: Sudan. (a) License requirements. (1) If AT column 1 or AT... ECCN, a license is required for export to Sudan for anti-terrorism purposes. 1 AT column 1 refers...

  7. 31 CFR 538.505 - Provision of certain legal services to the Government of Sudan, persons in Sudan, or benefitting...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Provision of certain legal services to the Government of Sudan, persons in Sudan, or benefitting Sudan. 538.505 Section 538.505 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS...

  8. The question of Sudan: a hydroeconomic optimization model for the Sudanese Nile

    NASA Astrophysics Data System (ADS)

    Satti, S.; Zaitchik, B.; Siddiqui, S.

    2014-10-01

    The effects of development and the uncertainty of a changing climate in East Africa pose myriad challenges for water managers along the Blue Nile. Sudan's large irrigation potential, hydroelectric dams, and prime location within the basin mean that Sudan's water management decisions will have great social, economic and political implications within the region. At the same time, Sudan's water use options are constrained by tradeoffs between upstream irrigation developments and downstream hydropower facilities as well as by the country's commitments under existing or future transboundary water sharing agreements. Here, we present a model that can be applied to evaluate optimal allocation of surface water resources to irrigation and hydropower in the Sudanese portion of the Blue Nile. Hydrologic inputs are combined with agronomic and economic inputs to formulate an optimization model within the General Algebraic Modeling System (GAMS). A sensitivity analysis is performed by testing model response to a range of economic conditions and to changes in the volume and timing of hydrologic flows. Results indicate that changing hydroclimate inputs have the capacity to greatly influence the productivity of Sudan's water resources infrastructure. Results also show that the economically optimal volume of water consumption, and thus the importance of existing treaty constraints, is sensitive to the perceived value of agriculture relative to electricity as well as to changing hydrological conditions.

  9. The New South as Curriculum: Implications for Understanding Southern Race Relations.

    ERIC Educational Resources Information Center

    Castenell, Louis A.

    The culture of the southern United States is examined in the context of its effects on race relations and how it is portrayed in curriculum. Many of the southern racial tragedies of the past are still unresolved and this is reflected in schools as they teach about the South. Since schools are dependent on published materials to teach classes, and

  10. Political Implications of the Southern African Development Community Agenda on Educational Development in the Region.

    ERIC Educational Resources Information Center

    Nziramasanga, Caiphas T.

    This paper briefly describes the historical development of the Southern African Development Coordination Conference (SADCC) from its roots in 1980 and examines the work of the Southern African Development Community (SADC) today. The objectives of the SADCC are listed from the 1980 declaration and the achievement of those objectives are assessed.…

  11. Not just about sunburn--the ozone hole's profound effect on climate has significant implications for Southern Hemisphere ecosystems.

    PubMed

    Robinson, Sharon A; Erickson, David J

    2015-02-01

    Climate scientists have concluded that stratospheric ozone depletion has been a major driver of Southern Hemisphere climate processes since about 1980. The implications of these observed and modelled changes in climate are likely to be far more pervasive for both terrestrial and marine ecosystems than the increase in ultraviolet-B radiation due to ozone depletion; however, they have been largely overlooked in the biological literature. Here, we synthesize the current understanding of how ozone depletion has impacted Southern Hemisphere climate and highlight the relatively few documented impacts on terrestrial and marine ecosystems. Reviewing the climate literature, we present examples of how ozone depletion changes atmospheric and oceanic circulation, with an emphasis on how these alterations in the physical climate system affect Southern Hemisphere weather, especially over the summer season (December-February). These potentially include increased incidence of extreme events, resulting in costly floods, drought, wildfires and serious environmental damage. The ecosystem impacts documented so far include changes to growth rates of South American and New Zealand trees, decreased growth of Antarctic mosses and changing biodiversity in Antarctic lakes. The objective of this synthesis was to stimulate the ecological community to look beyond ultraviolet-B radiation when considering the impacts of ozone depletion. Such widespread changes in Southern Hemisphere climate are likely to have had as much or more impact on natural ecosystems and food production over the past few decades, than the increased ultraviolet radiation due to ozone depletion. PMID:25402975

  12. Avalonian crustal controls on basin evolution: implications for the Mesozoic basins of the southern North Sea

    NASA Astrophysics Data System (ADS)

    Smit, Jeroen; van Wees, Jan-Diederik; Cloetingh, Sierd

    2015-04-01

    Little is known of the Southern North Sea Basin's (SNSB) Pre-Permian basement due to a lack of outcrop and cores. The nature and structure of the East Avalonian crust and lithosphere remain even less constrained in the absence of deep seismic (refraction) lines. However, various studies have hinted at the importance of the Reactivation of the Early Carboniferous fault network during each consecutive Mesozoic and Cenozoic tectonic phase, demonstrating the key role of weak zones from the Early Carboniferous structural grain in partitioning of structural deformation and vertical basin motions at various scales. Although the older basin history and the basement attract increasing attention, the Pre-Permian tectonics of the SNSB remains little studied with most attention focused on the Permian and younger history. The strong dispersal of existing constraints requires a comprehensive study from Denmark to the UK, i.e. the East Avalonian microplate, bordered by the Variscan Rheïc suture, the Atlantic and Baltica. Based on an extensive literature study and the reinterpretation of publicly available data, linking constraints from the crust and mantle to stratigraphic-sedimentological information, we complement the map of Early Carboniferous rifting of East Avalonia and propose a new tectonic scenario. From the reinterpretation of the boundary between Avalonia and Baltica we propose a new outline for the Avalonian microplate with implications for the tectonics of the North German Basin. Furthermore, we highlight the nature and extent of the major crustal/lithospheric domains with contrasting structural behaviour and the major boundaries that separate them. Results shed light on the effects of long lived differences in crustal fabric that are responsible for spatial heterogeneity in stress and strain magnitudes and zonations of fracturing, burial history and temperature history. The geomechanical control of large crustal-scale fault structures will provide the constraints and geometrical and compositional input for local models of stress and strain. Results will be further used to validate and to test inferred erosion patterns and the potential effect on stress differentiation, in view of the exploration and production of (un)conventional hydrocarbons.

  13. Ebola haemorrhagic fever in Sudan, 1976

    PubMed Central

    1978-01-01

    A large outbreak of haemorrhagic fever (subsequently named Ebola haemorrhagic fever) occurred in southern Sudan between June and November 1976. There was a total of 284 cases; 67 in the source town of Nzara, 213 in Maridi, 3 in Tembura, and 1 in Juba. The outbreak in Nzara appears to have originated in the workers of a cotton factory. The disease in Maridi was amplified by transmission in a large, active hospital. Transmission of the disease required close contact with an acute case and was usually associated with the act of nursing a patient. The incubation period was between 7 and 14 days. Although the link was not well established, it appears that Nzara could have been the source of infection for a similar outbreak in the Bumba Zone of Zaire. In this outbreak Ebola haemorrhagic fever was a unique clinical disease with a high mortality rate (53% overall) and a prolonged recovery period in those who survived. Beginning with an influenza-like syndrome, including fever, headache, and joint and muscle pains, the disease soon caused diarrhoea (81%), vomiting (59%), chest pain (83%), pain and dryness of the throat (63%), and rash (52%). Haemorrhagic manifestations were common (71%), being present in half of the recovered cases and in almost all the fatal cases. Two post mortems were carried out on patients in November 1976. The histopathological findings resembled those of an acute viral infection and although the features were characteristic they were not exclusively diagnostic. They closely resembled the features described in Marburg virus infection, with focal eosinophilic necrosis in the liver and destruction of lymphocytes and their replacement by plasma cells. One case had evidence of renal tubular necrosis. Two strains of Ebola virus were isolated from acute phase sera collected from acutely ill patients in Maridi hospital during the investigation in November 1976. Antibodies to Ebola virus were detected by immunofluorescence in 42 of 48 patients in Maridi who had been diagnosed clinically, but in only 6 of 31 patients in Nzara. The possibility of the indirect immunofluorescent test not being sufficiently sensitive is discussed. Of Maridi case contacts, in hospital and in the local community, 19% had antibodies. Very few of them gave any history of illness, indicating that Ebola virus can cause mild or even subclinical infections. Of the cloth room workers in the Nzara cotton factory, 37% appeared to have been infected, suggesting that the factory may have been the prime source of infection. ImagesFig. 4Fig. 5Fig. 3Fig. 6Fig. 7 PMID:307455

  14. Aetiology of Oral Cancer in the Sudan

    PubMed Central

    2013-01-01

    ABSTRACT Objectives To review the studied risk factors that linked to aetiology of oral cancer in the Sudan. There have been numerous reports in the increase in the incidence of oral cancer from various parts of the world. A recent trend for a rising incidence of oral cancer, with the absence of the well established risk factors, has raised concern. Although, there are inconsistent data on incidence and demographical factors, studies suggest that the physiologic response to risk factors by men and women vary in different populations. Material and Methods This review principally examines 33 publications devoted to aetiology of oral cancer in the Sudan, in addition to some risk factors that are commonly practiced in the Sudan. Results Several studies examining risk factors for oral cancer include tobacco use (Smoked and Smokeless), alcohol consumption, occupational risk, familial risk, immune deficits, virus infection and genetic factors. Conclusions Toombak use and infection with high risk Human Papilloma Virus (HPV) were extensively investigated and linked to the aetiology of oral cancer in Sudan. PMID:24422031

  15. Buried troughs, grabens and rifts in Sudan

    NASA Astrophysics Data System (ADS)

    Salama, R. B.

    The deep lineaments and shear patterns of Sudan follow two main directions :NNW (Red Sea trend) and ENE (Gulf of Aden trend). Precambrian mobile belts trend NE and NW. Palaezoic(?) sediments occupy NE-SW aligned grabens. Mesozoic continental sediments with NW paleotrends were deposited in two major depressions also aligned NW. Cainozoic uplift and volcanism was associated with domal uplifts along NE and SE axes. Fracturing and faulting in NW and NE directions resulted in the formation of NW-SE fault bounded grabens ranging in depth from 1 to 11 km. Extending from the western boundaries of Sudan to the eastern borders with Ethiopia, the Sudanese Cainozoic rift systemforms the largest rift system in Africa and includes: (a) Bahr E1 Arab Rift, (b) White Nile Rift, (c) Blue Nile Rift, (d) River Atbara Rift and (e) Wadi El Kuu Rift. The grabens and trouhs within the rift system form the main groundwater basins of Sudan. The discovery of oil in three of these rifts will encourage the exploration for oil in the others and a search for similar structures in the northern areas of Sudan.

  16. 3 CFR - Presidential Determination on Sudan

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 3 The President 1 2011-01-01 2011-01-01 false Presidential Determination on Sudan Presidential... the United States of America, including section 908(a)(3) of the Trade Sanctions Reform and Export Enhancement Act of 2000, title IX, Public Law 106-387, as amended, 22 U.S.C. 7207(a)(3) (TSRA), I...

  17. Trachoma in the Sudan. A laboratory study.

    PubMed Central

    Salim, A R; Sheikh, H A

    1975-01-01

    Out of 46 patients in the Sudan who had been diagnosed clinically as having trachoma 25 strains of the trachoma agent were isolated. Bacterial contamination was easily controlled by streptomycin and vancomycin. On repeated passaging, chick embryos lost their susceptibility to the trachoma agent during the summer. PMID:1203228

  18. Tectonic implications of the microearthquake seismicity and fault plane solutions in southern Peru

    NASA Technical Reports Server (NTRS)

    Grange, F.; Hatzfeld, D.; Cunningham, P.; Molnar, P.; Roecker, S. W.; Suarez, G.; Rodrigues, A.; Ocola, L.

    1984-01-01

    Because the contortion in the seismic zone in southern Peru is aligned approximately parallel to the direction of relative plate motion, rather than perpendicular to the coast of Peru, the position of the contortion need not migrate with respect to the overriding South American plate as the Nazca plate subducts beneath it, and the flow in the surrounding asthenosphere could be in a steady state. In addition, the position of the contortion defines the northern boundary of the volcanic arc in southern Peru. The inference that a wedge of asthenospheric material must overlie the downgoing slab for subduction-related volcanism to occur is thereby strengthened.

  19. The emerging European immigration regime: some reflections on implications for southern Europe.

    PubMed

    Baldwin-edwards, M

    1997-12-01

    "Immigration is one of the more controversial areas in the history of European integration. Whilst northern European countries have been constructing elaborate compromises in the European Union (EU) Treaties and in the Schengen group, southern European countries have been trying to construct their own immigration policies. Little attention has been paid in the literature to the relationship between these two phenomena: it is suggested here that southern countries have found it expedient to fit in with EU and Schengen arrangements, even though these appear impossible to implement. This contradiction is seen as intrinsic to the overall relations of Portugal, Spain, Italy and Greece to the EU." PMID:12293846

  20. A Grammar of Northern and Southern Gumuz

    ERIC Educational Resources Information Center

    Ahland, Colleen Anne

    2012-01-01

    Gumuz is a Nilo-Saharan dialect cluster spoken in the river valleys of northwestern Ethiopia and the southeastern part of the Republic of the Sudan. There are approximately 200,000 speakers, the majority of which reside in Ethiopia. This study is a phonological and grammatical analysis of two main dialects/languages: Northern Gumuz and Southern

  1. Dissertation Citations in Organismal Biology at Southern Illinois University at Carbondale: Implications for Collection Development

    ERIC Educational Resources Information Center

    Nabe, Jonathan; Imre, Andrea

    2008-01-01

    We report on a citation analysis of Ph.D. dissertations in plant biology and zoology at Southern Illinois University Carbondale, undertaken to test the common assumption that scientists favor current research to such an extent that journal backfiles can be de-emphasized in academic library collections. Results demonstrate otherwise. The study is…

  2. Rehabilitation of the expanded programme on immunization in Sudan following a poliomyelitis outbreak.

    PubMed Central

    ElZein, H. A.; Birmingham, M. E.; Karrar, Z. A.; Elhassan, A. A.; Omer, A.

    1998-01-01

    In 1993 a large outbreak of paralytic poliomyelitis occurred in Sudan as a result of an accumulation of large numbers of susceptible children that was accelerated by faltering immunization services. The extent of the outbreak led to the rapid rehabilitation of Sudan's Expanded Programme on Immunization (EPI); the government began financing vaccine purchase, operational aspects of EPI were decentralized, vaccine delivery was changed from a mobile to a fixed-site strategy, a solar cold chain network was installed, inservice training was resuscitated, and social mobilization was enhanced. National immunization days (NIDs) for poliomyelitis eradication were conducted throughout the country, including the southern states during a cease fire in areas of conflict. Measles immunization coverage was increased by offering measles vaccine during the second round of NIDs and subsequently through routine immunization services. Supplemental tetanus toxoid immunization of women of child-bearing age began in three provinces at high risk for neonatal tetanus. From 1994 to 1996 reported immunization coverage increased and the incidence of all EPI target diseases fell. Trends in coverage, disease incidence, financing, and the implementation of WHO-recommended disease-control strategies suggest that more sustainable immunization services have been re-established in Sudan. PMID:9803584

  3. Incidence of bluetongue virus precipitating antibodies in sera of some domestic animals in the Sudan.

    PubMed Central

    Eisa, M.; Karrar, A. E.; Abd Elrahim, A. H.

    1979-01-01

    To determine the presence and prevalence of bluetongue (BT) infection in a variety of domestic animal species in different geographical regions of the Sudan, a serological study using the agar gel precipitation technique was initiated. A total of 2142 serum samples were examined. Of the numbers tested approximately 28% of sheep, 11.2% of goats, 8% of cattle and 4.9% of camels were positive for group-specific antibodies to BT virus antigen, indicating previous exposure to BT infection. None of the samples tested from horses or donkeys were positive. The findings suggest that the disease is widely distributed in most parts of the Sudan where possible insect vectors prevail and may be endemic in sheep in Juba District, Equatoria Province, Southern Region. Goats appeared to have some degree of resistance to infection compared with sheep, and there seemed to be no significant differences in positive rates between farm and free-range cattle. It is concluded that BT infection may cause clinical disease in sheep, while it is probably subclinical or inapparent in goats, cattle and camels of the Sudan. PMID:229163

  4. The Botrychiopsis genus and its biostratigraphic implications in Southern Paraná Basin.

    PubMed

    Jasper, André; Guerra-Sommer, Margot; Cazzulo-Klepzig, Miriam; Menegat, Rualdo

    2003-12-01

    Botrychiopsis has been considered an important floristic element of Westphalian/Artinskian associations of the Paraná Basin. The occurrence of Botrychiopsis in roof-shales of the Rio Bonito Formation in Southern Paraná Basin (Quitéria area), supported by the identification of Botrychiopsis valida, enlarges the genus biochron. Consequently, the stratigraphic hierarchy for Botrychiopsis plantiana and Botrychiopsis valida was defined for the Paraná Basin. Although it is climatically controlled and related to a deglaciation icehouse stage, stratigraphic distribution of the genus presents a substantial climate tolerance, from cold/cool to warm/temperate conditions. A new phytostratigraphic zonation is proposed for the southern portion of the basin that includes the Botrychiopsis Zone (Asselian/Kungurian), which is subdivided into the Botrychiopsis plantiana (Asselian/Artinskian) and Botrychiopsis valida (Late Artinskian/Kungurian) subzones. PMID:14605684

  5. Glacial-interglacial variability in diatom abundance and valve size: Implications for Southern Ocean paleoceanography

    NASA Astrophysics Data System (ADS)

    Nair, Abhilash; Mohan, Rahul; Manoj, M. C.; Thamban, Meloth

    2015-10-01

    Antarctic sea ice extent along with Southern Ocean biological productivity varied considerably during glacial-interglacial periods, and both are known to have played a considerable role in regulating atmospheric CO2 variations in the past. Here we present data on diatom absolute abundance (valves/g of sediment) and size over the past ~ 42 ka B.P. and how they link to glacial-interglacial changes in Antarctic sea ice extent, Southern Ocean frontal systems, and aeolian dust flux. Our records of sea ice and permanent open ocean zone diatom abundances suggest a shift in the Antarctic winter sea ice limit and Polar Front respectively up to the modern-day Polar Frontal Zone during marine isotopic stages (MIS) 2 and late MIS 3. In addition to glacial shifts in the Polar Front, diatom assemblages also recorded a plausible northward shifts in Polar Front during few intervals of MIS 1. Glacial periods north of the Polar Front in the Indian sector of the Southern Ocean were characterized by higher total diatom abundance, larger Fragilariopsis kerguelensis apical length, and Thalassiosira lentiginosa radius. This is probably a consequence of (1) a northward expansion of the opal belt, a region characterized by high production and export of biogenic silica; (2) an increase in terrigenous input, via erosion of Crozet Islands; and (3) the alleviation of iron deficit by high input of Fe-bearing dust. The larger and highly silicified diatoms such as F. kerguelensis and T. lentiginosa may have mainly contributed in transporting biogenic silica and organic carbon to the seabed for the last 42 ka, in the northern Polar Frontal Zone of the Indian sector of the Southern Ocean.

  6. Age and origin of cold climate landforms from the Eastern Cape Drakensberg, southern Africa: palaeoclimatic implications

    NASA Astrophysics Data System (ADS)

    Mills, Stephanie C.; Barrows, Timothy T.; Fifield, L. Keith

    2014-05-01

    Reliable dating is crucial for resolving the nature and timing of cold events in southern Africa and the associated cold climate landforms produced. Evidence for glaciation has been proposed for the Eastern Cape Drakensberg, based on the identification of moraines that were presumed to be of last glacial maximum age. Temperature depressions of 10-17°C have been proposed for this region, based on the presence of these moraines (Lewis and Illgner, 2001) and the identification of a relict rock glacier. Such large temperature depressions are, however, unsupported by other palaeoclimatic proxies in southern Africa. Debate regarding the occurrence of glaciation in southern Africa has been ongoing for several decades. There is good evidence for small-scale glaciation during the last glacial cycle in Lesotho, at elevations exceeding 3000 m a.s.l., but these sites are more than 1000 m higher in elevation than those identified in the Eastern Cape, and suggest a temperature depression of only ~6°C and a change to a winter dominated precipitation regime during the last glacial cycle. This paper presents preliminary cosmogenic nuclide exposure ages for the Eastern Cape 'moraines' and a periglacial blockstream in this region. We discuss potential alternative interpretations for the formation of the landforms and suggest that glaciers were absent in the Eastern Cape Drakensberg during the last glacial period. However, there is widespread evidence for periglacial activity down to an elevation of ~1700 m a.s.l., as illustrated by extensive blockstreams, stone garlands and solifluction deposits. These periglacial deposits suggest that the climate was much colder (~6ºC) during the last glacial cycle, in keeping with other proxy records, but not cold enough to initiate or sustain glaciers at low elevations. References Lewis C. A., Illgner, P. M., 2001. Late Quaternary glaciation in Southern Africa: moraine ridges and glacial deposits at Mount Enterprise in the Drakensberg of the Eastern Cape Province, South Africa. Journal of Quaternary Science 16, 365-374.

  7. Color variations of the Quaternary Red Clay in southern China and its paleoclimatic implications

    NASA Astrophysics Data System (ADS)

    Hu, Xue-Feng; Du, Yan; Guan, Chun-Lei; Xue, Yong; Zhang, Gan-Lin

    2014-04-01

    The red clay and red weathering crust are widely distributed in southern China. To study the possible relationship between soil color and paleoclimatic environment, three color parameters, lightness (L*), redness (a*) and yellowness (b*), of twelve Quaternary Red Clay (QRC) profiles in southern China were measured using a colorimeter. Colors of the QRC profiles vary vertically: a* and b* generally increase downward and L* decreases downwards. Colors of the QRC also show spatial variation: a* and b* generally increase towards the equator; whereas L* increases away from it. Both a* and b* are positively significantly correlated with clay (< 2 μm) content, free Fe (Fed), Fed/Fet ratios and other soil weathering indices of the QRC (ρ < 0.05), and the correlations between a* and the weathering indices are much stronger than those between b* and the indices. a* mainly reflects hematite content in soils. Compared with magnetic susceptibility (χ), a* of the QRC is a more promising paleoclimatic indicator, although it is sometimes disturbed by uneven parent materials and dissolution of hematite by water logging. The upward decrease of a* of the QRC profiles reflects a cooling and drying paleoclimate since the end of the Last Interglacial, and the spatial variation of a* coincides with more optimum hydrothermal conditions in lower-latitude areas of southern China.

  8. Forest to agriculture conversion in southern Belize: Implications for migrant land birds

    USGS Publications Warehouse

    Spruce, J.P.; Dowell, B.A.; Robbins, C.S.; Sader, S.A.

    1993-01-01

    Central America offers a suite of neotropical habitats vital to overwintering migrant land birds. The recent decline of many forest dwelling avian migrants is believed to be related in part to neotropical deforestation and land use change. However, spatio-temporal trends in neotropical habitat availability and avian migrant habitat use are largely unknown. Such information is needed to assess the impact of agriculture conversion on migrant land birds. In response, the USDI Fish and Wildlife Service and the University of Maine began a cooperative study in 1988 which applies remote sensing and field surveys to determine current habitat availability and avian migrant habitat use. Study sites include areas in Belize, Costa Rica, Guatemala and southern Mexico. Visual assessment of Landsat TM imagery indicates southern Belize forests are fragmented by various agricultural systems. Shifting agriculture is predominant in some areas, while permanent agriculture (citrus and mixed animal crops) is the primary system in others. This poster focuses on efforts to monitor forest to agriculture conversion in southern Belize using remote sensing, field surveys and GIS techniques. Procedures and avian migrant use of habitat are summarized.

  9. Lagrangian tracing of Sahelian Sudan moisture sources

    NASA Astrophysics Data System (ADS)

    Salih, Abubakr A. M.; Zhang, Qiong; Tjernström, Michael

    2015-07-01

    The Sahelian Sudan is an arid to semiarid region that depends on the seasonal rainfall as the main source of water, but its rainfall has large interannual variability. Such dry regions usually have their main moisture sources elsewhere; thus, the rainfall variability is directly related to the moisture transport. This study seeks to identify source regions of water vapor for Sahelian Sudan during the monsoon period, from July to September. We have used the Lagrangian trajectory model FLEXPART driven by ERA-Interim reanalysis for the time period 1998 to 2008. The results show that most of the air masses that reach this region during the monsoon period have their major origins over the Arabian Peninsula, Central Africa, or are associated with the tropical easterly jet. Flow associated with Intertropical Convergence Zone contributes almost half of the total precipitated water; most of it comes from Central Africa. This suggests that moisture recycling is the major contributor, compared to Oceanic sources. The flows from the northeast (Arabian Peninsula and north Asia) and east (Horn of Africa and north Indian Ocean) contribute about one third of the precipitated water. The rest of precipitated water comes from the Mediterranean, subtropical Atlantic, and western Sahel, all with smaller contribution. Our results also indicate that different subregions of Sahelian Sudan have different moisture sources. Such result needs to be taken into account in seasonal forecasting practices.

  10. Three-dimensional lithospheric electrical structure of Southern Granulite Terrain, India and its tectonic implications

    NASA Astrophysics Data System (ADS)

    Patro, Prasanta K.; Sarma, S. V. S.; Naganjaneyulu, K.

    2014-01-01

    crustal as well as the upper mantle lithospheric electrical structure of the Southern Granulite Terrain (SGT) is evaluated, using the magnetotelluric (MT) data from two parallel traverses: one is an ~ 500 km long N-S trending traverse across SGT and another a 200 km long traverse. Data space Occam 3-D inversion was used to invert the MT data. The electrical characterization of lithospheric structure in SGT shows basically a highly resistive (several thousands of Ohm meters) upper crustal layer overlying a moderately resistive (a few hundred Ohm meters) lower crustal layer which in turn is underlain by the upper mantle lithosphere whose resistivity shows significant changes along the traverse. The highly resistive upper crustal layer is interspersed with four major conductive features with three of them cutting across the crustal column, bringing out a well-defined crustal block structure in SGT with individual highly resistive blocks showing correspondence to the geologically demarcated Salem, Madurai, and Trivandrum blocks. The 3-D model also brought out a well-defined major crustal conductor located in the northern half of the Madurai block. The electrical characteristics of this south dipping conductor and its close spatial correlation with two of the major structural elements, viz., Karur-Oddanchatram-Kodaikanal Shear Zone and Karur-Kamban-Painavu-Trichur Shear Zone, suggest that this conductive feature is closely linked to the subduction-collision tectonic processes in the SGT, and it is inferred that the Archean Dharwar craton/neoproterozoic SGT terrain boundary lies south of the Palghat-Cauvery shear zone. The results also showed that the Achankovil shear zone is characterized by a well-defined north dipping conductive feature. The resistive block adjoining this conductor on the southern side, representing the Trivandrum block, is shown to be downthrown along this north dipping crustal conductor relative to the Madurai block, suggesting a northward movement of Trivandrum block colliding against the Madurai block. The lithospheric upper mantle electrical structure of the SGT up to a depth of 100 km may be broadly divided into two distinctly different segments, viz., northern and southern segments. The northern lithospheric segment, over a major part, is characterized by a thick resistive upper mantle, while the southern one is characterized by a dominantly conductive medium suggesting a relatively thinned lithosphere in the southern segment.

  11. Density variations between the southern and northern hemisphere of Mars: Implications from gravimetric inversion

    NASA Astrophysics Data System (ADS)

    Breuer, D.; Pauer, M.

    2008-12-01

    One remarkable feature of Mars is the crustal dichotomy which divides the surface into an old southern highland hemisphere rising several kilometers above the zero level and a superficially younger northern lowlands hemisphere well below the datum. Whether this crustal dichotomy is also reflected in composition, density, and thickness is not known -- although, a crustal thickness variation is generally suggested based on the assumption of a constant crustal density. We used gravimetric methods to place constraints on the maximum crustal density of the southern highlands. Gravimetric methods are ambiguous with a noted trade- off between the crustal thickness and density. However, combining two different methods, the geoid- topography ratio and Bouguer inversion, helps to constrain a maximum density of the crust for regions that show a homogeneous unit with respect to lateral density variations and compensation state. For the Martian Noachian southern highlands a combination of these methods suggests a maximum crustal density of 3020 ± 70 kgm-3, assuming a single-layer crustal structure. Two-layer crustal structures show similar results: the upper crustal density is also limited to ~ 3000 kgm-3, but a denser uniformly thick lower crust is possible. The obtained results together with the findings on crustal densities (and composition) of other regions on Mars are consistent with various scenarios of crustal evolution: 1) A 'temporal' evolution in the densities with low densities of the ancient crust and comparatively higher densities of the young (Amazonian-era) volcanic material. Such a 'temporal' increase may result from different formation mechanisms or possibly from a change in composition of the basaltic magmas over time. 2) The density variation is already manifested in the early evolution during the formation of the crustal dichotomy, i.e. the Noachian crust of the northern lowlands has a different density than the Noachian southern highland crust. The ancient northern hemisphere might have a higher density than the crust of the ancient southern hemisphere, assuming the high density crust of the Elysium region being representative for the entire Northern lowlands. If correct, this also suggests a much lower curst-mantle undulation as generally assumed. 3) As in case 2, the density variation is already manifested in the early evolution during the formation of the crustal dichotomy. However, in contrast to case 2, the ancient northern hemisphere has a lower density than the crust of the ancient southern hemisphere as suggested by TES data. The spectra can be interpreted as basalt in the southern hemisphere and andesite in the northern hemisphere. A consequence of that density variation is a stronger crust-mantle undulation than assumed by Bouguer inversion with constant crust density. In the subsequent evolution of dichotomy formation and bulk crust formation, the volcanism in Elysium and Tharsis becomes more enriched in iron and therefore shows an increasing density.

  12. Fore-arc Counterclockwise Rotation In Southern Mexico: Implications For The NA-CA-CO Triple Junction

    NASA Astrophysics Data System (ADS)

    Andreani, L.; Le Pichon, X.; Rangin, C.; Martinez-Reyes, J.

    2007-12-01

    Numerous studies, mainly based on structural and paleomagnetic data, consider the Southern Mexico as a crustal block (Southern Mexico Block, SMB) uncoupled from the North American plate with a southeast motion with respect to North America accommodated by extension through the central Trans-Mexican Volcanic Belt (TMVB). On the other hand, the accommodation of this motion on the southeastward boundary, especially at the Cocos/Caribbean/North American triple junction is still debated. The boundary between the SMB and the North American plate is constituted by three connected zones of deformation: (1) left-lateral transtension across the central TMVB, (2) left-lateral strike-slip faulting along the eastern TMVB and Veracruz area and (3) reverse and left- lateral strike-slip faulting in the Chiapas area. We show that these three active deformation zones accommodate a couterclockwise rotation of the SMB with respect to the North American plate. We specially discuss the Quaternary motion of the SMB with respect to the surrounding plates near the Cocos/Caribbean/North American triple junction. The model we propose predicts a Quaternary couterclockwise rotation of 0.45 deg/Ma with a pole located at 24.2N and 91.8W. Finally we discuss the geodynamic implications of this counterclockwise rotation. The Southern Mexico Block motion is generally assumed to be the result of slip partitioning at the trench. However the obliquity of the subduction is too small to explain slip partitioning. The motion could be facilitated by the high thermal gradient and gravitational collapse that affects central Mexico or by partial coupling with the eastward motion of the Caribbean plate.

  13. The Southern Survey of Agricultural Majors: Some Implications for the Future of Higher Education in Agriculture.

    ERIC Educational Resources Information Center

    Cosby, Arthur G.

    The increased enrollment of women in Colleges of Agriculture has implications for the training and socializing of agriculture professionals in the future. The female students represent fundamental changes in the character of agricultural enrollment. They are more likely to be young, single, and politically moderate or liberal. They are less likely…

  14. Southern dispersal and Palaeoecological implications of woolly rhinoceros ( Coelodonta antiquitatis): review of the Iberian occurrences

    NASA Astrophysics Data System (ADS)

    Álvarez-Lao, Diego J.; García, Nuria

    2011-07-01

    Cold-adapted large mammal populations spread southward during the coldest and driest phases of the Late Pleistocene reaching the Iberian Peninsula. Presence of woolly rhinoceros ( Coelodonta antiquitatis) can be identified from 23 Iberian sites, which is compiled and analyzed herein, and the fossil specimens from seven of these sites are described here for first time. Morphological and biometrical analyses demonstrate that the Iberian woolly rhinoceros did not significantly differ from individuals of other European populations, but represent the westernmost part of a continuous Eurasian belt of distribution. The first presence of woolly rhino in the Iberian Peninsula has been identified during the late Middle Pleistocene and early Late Pleistocene. However, the highest abundance of this species is recorded during MIS 3 and 2. The latest Iberian occurrences can be dated around 20 ka BP. The presence of woolly rhinoceros in the Iberian Peninsula correlates with periods of extreme dry and cold climatic conditions documented in Iberian terrestrial and marine sediment sequences. From a palaeobiogeographic point of view, the maximum southern spread of C. antiquitatis on the Iberian Peninsula was registered during the late Middle Pleistocene or early Late Pleistocene, reaching the latitude of Madrid (about 40°N). Subsequently, during MIS 3 and 2, all Iberian finds were restricted to the Northern regions of Iberia (Cantabrian area and Catalonia). The southern expansion of C. antiquitatis during the Late Pleistocene in the Iberian Peninsula reached similar latitudes to other Eurasian regions. The ecological composition of fossil assemblages with presence of woolly rhinoceros was statistically analyzed. Results show that temperate ungulate species are predominant at Iberian assemblages, resulting in a particular mixture of temperate and cold elements different of the typical Eurasian cold-adapted faunal associations. This particular situation suggests two possible explanations: a) Eventual migrations during the coldest time spans, resulting in a mixing of cold and temperate faunas, instead a faunal replacing; b) Persistence of woolly rhinoceros populations in the Iberian Peninsula during interglacial episodes confined at cryptic southern refugia.

  15. Three-dimensional resistivity structure of Southern Alberta, Canada: implications for Precambrian tectonics

    NASA Astrophysics Data System (ADS)

    Nieuwenhuis, Greg; Unsworth, Martyn J.; Pana, Dinu; Craven, Jim; Bertrand, Edward

    2014-05-01

    The Precambrian basement rocks in southern Alberta are hidden beneath the Western Canada Sedimentary Basin, making studies of these rocks dependent on geophysical measurements. Magnetotelluric (MT) data were used to study the structure of these basement rocks through measurements of electrical resistivity. Long-period MT data collected in Southern Alberta during the Lithoprobe project were combined with new data to produce a grid of data that permitted a 3-D approach to data analysis. Dimensionality analysis suggested that data at periods less than 1000 s were relatively 2-D. However, 2-D inversion models of MT data in Alberta resulted in low resistivity features in the crust which moved dependant on the data included in the inversion. These features were previously attributed to crustal anisotropy. 3-D inversion yielded a resistivity model that fit the measured MT data and was well correlated with both the Precambrian domain boundaries and interpretations of other geophysical data. This MT data set defines a major upper-mantle conductor coincident with the Archean Loverna Block of the Hearne Domain. This anomaly is called the Loverna Conductor, and its southern boundary is defined by a pronounced increase in upper-mantle resistivity along the Vulcan Structure, which is an approximately 300-km-long linear potential field anomaly completely buried beneath the western Canada Sedimentary Basin. Since the lithosphere in this region was assembled ca. 1.9-1.8 Ga, the low resistivity anomaly in the upper mantle is not associated with recent tectonic activity. The Loverna Conductor was likely formed by the enrichment of the lithospheric mantle through subduction along the Vulcan Structure during the Proterozoic assembly of Laurentia. In particular, this model is consistent with recent interpretations which attribute the origin of the Vulcan Structure to collision along a north dipping subduction zone.

  16. Compositional heterogeneity of Asteroid 4 Vesta’s southern hemisphere: Implications for the Dawn mission

    NASA Astrophysics Data System (ADS)

    Reddy, Vishnu; Gaffey, Michael J.; Kelley, Michael S.; Nathues, Andreas; Li, Jian-Yang; Yarbrough, Robert

    2010-12-01

    High signal-to-noise, rotationally-resolved spectra of Asteroid 4 Vesta's southern hemisphere from the 2007 opposition were used to constrain its compositional and mineralogical variations. The spectra were rotationally-phased using closely timed HST observations of Vesta by Li et al. (Li, J.-Y., McFadden, L.A., Thomas, P.C., Mutchler, M.J., Parker, J.Wm., Young, E.F., Russell, C.T., Sykes, M.V., Schmidt, B.E. [2010]. Icarus 208, 238-251). The average surface of Vesta's southern hemisphere is analogous to a howardite or polymict eucrite assemblage similar to the northern hemisphere, although the band parameters are distinctly shifted towards the diogenite zone on the Band-Band plot. A few distinct compositional units were detected and they might be related to albedo features detected by Hubble Space Telescope (Li et al., 2010). We have identified two compositionally distinct regions overlaying the background surface. The first unit is a polymict eucrite and/or low-Ca eucrite compositional unit at 143° longitude that border the eucrite zone on the Band-Band plot and the second is a diogenite unit at 159°. While we did not detect any distinct olivine units as suggested by Gaffey (Gaffey, M.J. [1997]. Icarus 127, 130-157), we cannot rule out the possibility of smaller olivine-rich units that are below the detection limit of the instrumentation we used. Based on the analysis and the limitations of the data, we do not suggest that Vesta's surface is olivine-free. Mean pyroxene chemistry estimates for both hemispheres broadly agree with one another (to within one-sigma) with the northern hemisphere ferrosilite (Fs) and wollastonite (Wo) values being slightly higher than southern hemisphere.

  17. Surveying the context for the implementation of UPE in the Sudan

    NASA Astrophysics Data System (ADS)

    Hajjar, Habib

    1983-06-01

    In 1977 the Government of the Sudan adopted a Plan with the long-term aim of universalizing primary education by the end of 1990. In spite of real accomplishments in education since the launching of the UPE scheme, there is a widespread conviction that the attainment of this objective will be delayed far beyond 1990 unless serious measures are taken to modify existing trends and imbalances. The following article, based on available information from the Sudan and on a microplanning study undertaken jointly by IIEP and the Sudanese Ministry of Education in 1981, is an attempt to draw some lessons from the Sudanese experience of UPE, highlighting the major difficulties encountered in implementing this policy and raising some of the implications of such a scheme for planning methods and perspectives. Although a host of financial and material problems (lack of resources, problems of communication, etc.) may be pointed out, one must not forget the pressure of existing trends and imbalances such as the `upward thrust' in the development of the Sudanese school system, which contrasts with the top priority accorded in theory to primary education. The existing planning methods laid down by the central level and formed within a uniform and general setting, scarcely suit the variety of local situations in a country like the Sudan where the different regions are very diverse in their geographic, economic, ethnic and political composition.

  18. Orbital remote sensing for geological mapping in southern Tunisia: Implication for oil and gas exploration

    NASA Astrophysics Data System (ADS)

    Peña, Sherrie A.; Abdelsalam, Mohamed G.

    2006-02-01

    Southern Tunisia is dominated by early to middle Triassic continental sandstones inter-bedded with shales and conglomerates followed by late Triassic shallow marine carbonates, lower Jurassic evaporates, and upper Jurassic to lower Cretaceous clastic sedimentary rocks. These constitute the Dahar Plateau (which is part of the Ghadames Basin and it is the focus of this study) that was developed in association with regional uplift of the Saharan Platform. Efforts in mapping the details of surface geology in southern Tunisia are hindered by the lack of continuous bedrock outcrops, where some of the formations are buried under the sand of the Sahara Desert. Remote sensing data including multi-spectral optical (Landsat Enhanced Thematic Mapper (ETM+) and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)), radar (RADARSAT), and Digital Elevation Models (DEMs) extracted from the Shuttle Radar Topography Mission (SRTM) data are used to trace along strike continuity of different lithological units as well as mapping morphologically defined structures in southern Tunisia. Landsat ETM+ and ASTER Red-Green-Blue (RGB) color combination images (both band and band-ratio images) have been used for the identification of various lithological units when they are exposed on the surface. On the other hand, RADARSAT images have been utilized for tracing geological formations and geological structures that are buried under thin (˜1 m) sand. Fusion of optical and radar remote sensing data using Color Normalization Transformation (CNT) has been effectively implemented to further identify lithological units and geological structures. Hill-shading techniques are applied to SRTM DEMs to enhance terrain perspective views and to extract geomorphological features and morphologically defined structures through the means of lineament analysis. Results from remote sensing analysis are in good agreement with results obtained from in situ investigations including geological mapping and seismic exploration. Identifying lithological and structural features using remote sensing studies incorporated with surface and sub-surface geological investigations in southern Tunisia can aid exploration for new oil and gas fields. Such an approach of integrating remote sensing and in situ geological studies can be successfully adopted in other parts of North Africa and arid regions in general.

  19. 31 CFR 538.418 - Financial transactions in Sudan.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Financial transactions in Sudan. 538.418 Section 538.418 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued... Interpretations § 538.418 Financial transactions in Sudan. (a) Any financial transaction with a...

  20. 76 FR 68037 - Federal Acquisition Regulation; Sudan Waiver Process

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-02

    ... Federal Register at 75 FR 62069 on October 7, 2010, to revise FAR 25.702, Prohibition on contracting with... Operations in Sudan and Imports from Burma, in the Federal Register at 74 FR 40463 on August 11, 2009... Regulation; Sudan Waiver Process AGENCIES: Department of Defense (DoD), General Services Administration...

  1. 75 FR 62069 - Federal Acquisition Regulation; Sudan Waiver Process

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-07

    ... Operations in Sudan and Imports from Burma, in the Federal Register at 74 FR 40463 on August 11, 2009... Federal Acquisition Regulation; Sudan Waiver Process AGENCIES: Department of Defense (DoD), General... criteria that an agency must address in a waiver request and a waiver consultation process...

  2. Humpback whale song on the Southern Ocean feeding grounds: implications for cultural transmission.

    PubMed

    Garland, Ellen C; Gedamke, Jason; Rekdahl, Melinda L; Noad, Michael J; Garrigue, Claire; Gales, Nick

    2013-01-01

    Male humpback whales produce a long, complex, and stereotyped song on low-latitude breeding grounds; they also sing while migrating to and from these locations, and occasionally in high-latitude summer feeding areas. All males in a population sing the current version of the constantly evolving display and, within an ocean basin, populations sing similar songs; however, this sharing can be complex. In the western and central South Pacific region there is repeated cultural transmission of song types from eastern Australia to other populations eastward. Song sharing is hypothesized to occur through several possible mechanisms. Here, we present the first example of feeding ground song from the Southern Ocean Antarctic Area V and compare it to song from the two closest breeding populations. The early 2010 song contained at least four distinct themes; these matched four themes from the eastern Australian 2009 song, and the same four themes from the New Caledonian 2010 song recorded later in the year. This provides evidence for at least one of the hypothesized mechanisms of song transmission between these two populations, singing while on shared summer feeding grounds. In addition, the feeding grounds may provide a point of acoustic contact to allow the rapid horizontal cultural transmission of song within the western and central South Pacific region and the wider Southern Ocean. PMID:24278134

  3. Spatial genetic structure and regional demography in the southern torrent salamander: Implications for conservation and management

    USGS Publications Warehouse

    Miller, Mark P.; Haig, Susan M.; Wagner, R.S.

    2006-01-01

    The Southern torrent salamander (Rhyacotriton variegatus) was recently found not warranted for listing under the US Endangered Species Act due to lack of information regarding population fragmentation and gene flow. Found in small-order streams associated with late-successional coniferous forests of the US Pacific Northwest, threats to their persistence include disturbance related to timber harvest activities. We conducted a study of genetic diversity throughout this species' range to 1) identify major phylogenetic lineages and phylogeographic barriers and 2) elucidate regional patterns of population genetic and spatial phylogeographic structure. Cytochrome b sequence variation was examined for 189 individuals from 72 localities. We identified 3 major lineages corresponding to nonoverlapping geographic regions: a northern California clade, a central Oregon clade, and a northern Oregon clade. The Yaquina River may be a phylogeographic barrier between the northern Oregon and central Oregon clades, whereas the Smith River in northern California appears to correspond to the discontinuity between the central Oregon and northern California clades. Spatial analyses of genetic variation within regions encompassing major clades indicated that the extent of genetic structure is comparable among regions. We discuss our results in the context of conservation efforts for Southern torrent salamanders.

  4. Phylogeography and spatial genetic structure of the Southern torrent salamander: Implications for conservation and management

    USGS Publications Warehouse

    Miller, M.P.; Haig, S.M.; Wagner, R.S.

    2006-01-01

    The Southern torrent salamander (Rhyacotriton variegatus) was recently found not warranted for listing under the US Endangered Species Act due to lack of information regarding population fragmentation and gene flow. Found in small-order streams associated with late-successional coniferous forests of the US Pacific Northwest, threats to their persistence include disturbance related to timber harvest activities. We conducted a study of genetic diversity throughout this species' range to 1) identify major phylogenetic lineages and phylogeographic barriers and 2) elucidate regional patterns of population genetic and spatial phylogeographic structure. Cytochrome b sequence variation was examined for 189 individuals from 72 localities. We identified 3 major lineages corresponding to nonoverlapping geographic regions: a northern California clade, a central Oregon clade, and a northern Oregon clade. The Yaquina River may be a phylogeographic barrier between the northern Oregon and central Oregon clades, whereas the Smith River in northern California appears to correspond to the discontinuity between the central Oregon and northern California clades. Spatial analyses of genetic variation within regions encompassing major clades indicated that the extent of genetic structure is comparable among regions. We discuss our results in the context of conservation efforts for Southern torrent salamanders. ?? The American Genetic Association. 2006. All rights reserved.

  5. Salp/krill interactions in the Southern Ocean: spatial segregation and implications for the carbon flux

    NASA Astrophysics Data System (ADS)

    Pakhomov, E. A.; Froneman, P. W.; Perissinotto, R.

    Available data on the spatial distribution and feeding ecophysiology of Antarctic krill, Euphausia superba, and the tunicate, Salpa thompsoni, in the Southern Ocean are summarized in this study. Antarctic krill and salps generally display pronounced spatial segregation at all spatial scales. This appears to be the result of a clear biotopical separation of these key species in the Antarctic pelagic food web. Krill and salps are found in different water masses or water mass modifications, which are separated by primary or secondary frontal features. On the small-scale (<100 km), Antarctic krill and salps are usually restricted to the specific water parcels, or are well segregated vertically. Krill and salp grazing rates estimated using the in situ gut fluorescence technique are among the highest recorded in the Antarctic pelagic food web. Although krill and salps at times may remove the entire daily primary production, generally their grazing impact is moderate (⩽50% of primary production). The regional ecological consequences of years of high salp densities may be dramatic. If the warming trend, which is observed around the Antarctic Peninsula and in the Southern Ocean, continues, salps may become a more prominent player in the trophic structure of the Antarctic marine ecosystem. This likely would be coupled with a dramatic decrease in krill productivity, because of a parallel decrease in the spatial extension of the krill biotope. The high Antarctic regions, particularly the Marginal Ice Zone, have, however, effective physiological mechanisms that may provide protection against the salp invasion.

  6. Humpback Whale Song on the Southern Ocean Feeding Grounds: Implications for Cultural Transmission

    PubMed Central

    Garland, Ellen C.; Gedamke, Jason; Rekdahl, Melinda L.; Noad, Michael J.; Garrigue, Claire; Gales, Nick

    2013-01-01

    Male humpback whales produce a long, complex, and stereotyped song on low-latitude breeding grounds; they also sing while migrating to and from these locations, and occasionally in high-latitude summer feeding areas. All males in a population sing the current version of the constantly evolving display and, within an ocean basin, populations sing similar songs; however, this sharing can be complex. In the western and central South Pacific region there is repeated cultural transmission of song types from eastern Australia to other populations eastward. Song sharing is hypothesized to occur through several possible mechanisms. Here, we present the first example of feeding ground song from the Southern Ocean Antarctic Area V and compare it to song from the two closest breeding populations. The early 2010 song contained at least four distinct themes; these matched four themes from the eastern Australian 2009 song, and the same four themes from the New Caledonian 2010 song recorded later in the year. This provides evidence for at least one of the hypothesized mechanisms of song transmission between these two populations, singing while on shared summer feeding grounds. In addition, the feeding grounds may provide a point of acoustic contact to allow the rapid horizontal cultural transmission of song within the western and central South Pacific region and the wider Southern Ocean. PMID:24278134

  7. Hyperpycnal sediment discharge from semiarid southern California rivers: Implications for coastal sediment budgets

    USGS Publications Warehouse

    Warrick, J.A.; Milliman, John D.

    2003-01-01

    Southern California rivers discharge hyperpycnal (river density greater than ocean density) concentrations of suspended sediment (>40 g/L, according to buoyancy theory) during flood events, mostly during El Nin??o-Southern Oscillation (ENSO) conditions. Because hyperpycnal river discharge commonly occurs during brief periods (hours to occasionally days), mean daily flow statistics often do not reveal the magnitude of these events. Hyperpycnal events are particularly important in rivers draining the Transverse Range and account for 75% of the cumulative sediment load discharged by the Santa Clara River over the past 50 yr. These events are highly pulsed, totaling only ??? 30 days (??? 0.15% of the total 50 yr period). Observations of the fate of sediment discharge, although rare, are consistent with hyperpycnal river dynamics and the high likelihood of turbidity currents during these events. We suggest that much of the sediment load initially bypasses the littoral circulation cells and is directly deposited on the adjacent continental shelf, thus potentially representing a loss of immediate beach sand supply. During particularly exceptional events (>100 yr recurrence intervals), flood underflows may extend past the shelf and escape to offshore basins.

  8. Phylogeography and spatial genetic structure of the Southern torrent salamander: implications for conservation and management.

    PubMed

    Miller, Mark P; Haig, Susan M; Wagner, R Steven

    2006-01-01

    The Southern torrent salamander (Rhyacotriton variegatus) was recently found not warranted for listing under the US Endangered Species Act due to lack of information regarding population fragmentation and gene flow. Found in small-order streams associated with late-successional coniferous forests of the US Pacific Northwest, threats to their persistence include disturbance related to timber harvest activities. We conducted a study of genetic diversity throughout this species' range to 1) identify major phylogenetic lineages and phylogeographic barriers and 2) elucidate regional patterns of population genetic and spatial phylogeographic structure. Cytochrome b sequence variation was examined for 189 individuals from 72 localities. We identified 3 major lineages corresponding to nonoverlapping geographic regions: a northern California clade, a central Oregon clade, and a northern Oregon clade. The Yaquina River may be a phylogeographic barrier between the northern Oregon and central Oregon clades, whereas the Smith River in northern California appears to correspond to the discontinuity between the central Oregon and northern California clades. Spatial analyses of genetic variation within regions encompassing major clades indicated that the extent of genetic structure is comparable among regions. We discuss our results in the context of conservation efforts for Southern torrent salamanders. PMID:17135462

  9. Seismicity and crustal structure studies of southern California: tectonic implications from improved earthquake locations

    SciTech Connect

    Corbett, E.J.

    1984-01-01

    The 5.1 M/sub L/ Santa Barbara earthquake of 13 August 1978 was located 3 km southeast of Santa Barbara at a focal depth of 12.7 km. The temporal-spatial development of the aftershock zone may indicate that the initial rupture plane was considerably smaller than that of the eventual aftershock zone. The aftershock hypocenters outline a nearly horizontal plane (dipping 15/sup 0/ or less) at 13-km depth and the preferred focal mechanism indicates north-over-south thrusting. To further test the decollement hypothesis, Caltech catalog locations were reviewed to determine the depth distribution of earthquakes in the Transverse Ranges. The seismogenic zone is thickest along the southern front of the Transverse Ranges and is thinnest in the southern Mojave Desert and at the east end of the Transverse Ranges. The seismicity of the western Transverse Ranges is typified by north-dipping planar structures and the eastern Transverse Ranges are typified by pervasive seismicity extending down to the floor of the seismogenic zone. Data from a large quarry explosion on Catalina Island were utilized to derive a 3-layer Continental Borderland velocity structure to improve the locations of the 1981 Santa Barbara Island earthquakes. The Santa Barbara Island earthquake (5.3 M/sub L/) occurred on September 4, 1981. Aftershocks exhibited a clear northwest-southeast alignment that coincides with the submarine escarpment of the Santa Cruz-Catalina fault and was consistent with focal mechanisms.

  10. Reasons behind the Failure of Teaching Sudan Practical Integrated National English (SPINE 5) in Sudan

    ERIC Educational Resources Information Center

    Hamad, Mona M.

    2015-01-01

    According to the development of English language learning and curriculum design, English language series became a very important issue that affects education globally and in Sudan. In specific, this study reports reasons behind the failure of teaching SPINE 5 (which is one of SPINE series) from the teachers' point of view. In Bahry Locality in…

  11. The impact of war on women and children: case study of Sudan.

    PubMed

    El-nagar, S E

    1992-06-01

    Civil war has raged in southern Sudan from 1955 to 1972 and again from 1983 to the present. This situation has been compounded by regional conflicts in other parts of Sudan and wars in neighboring countries. The consequences of war are taking their toll on the entire region and are intensified by environmental hazards, desertification, drought, and famine. The socioeconomic and educational infrastructure has been destroyed in southern Sudan, taking the family support system with it. The atmosphere of continued fighting has made it all but impossible for relief agencies to provide services. The innocent victims of the war are civilians who are forced to choose between disastrous alternatives: if they flee, they lose their homes, their livelihoods, and their communities; if they stay, they watch these things being destroyed around them. Women and children are suffering the most. Hunger and disease are widespread, and immunization programs have been curtailed. Very few school-age children are receiving an education, and children are subject to kidnapping and abuse from soldiers. There may be as many as 3 million people displaced, with 1.5 million living in settled areas and 707,000 in camps in the Khartoum area. Relief aid in the camps is unreliable, and the displace women arrive with no assets or skills. They survive through domestic work, begging, petty trading, or beer-brewing and prostitution (the latter 2 are illegal). Children are left to fend for themselves all day or to find work in situations where they are exploited. In addition to depriving the children of their health, education, and economic stability, the war has resulted in cultural deprivation as ethnic groups lose their sense of identity. Psychological problems are the natural consequence of this situation, and aggressive behavior is seen in the displaced children, while trauma and anxiety plague the children in the war zones. PMID:12318292

  12. Tectonic implications of a paleomagnetic study of the Sarmiento Ophiolitic Complex, southern Chile

    NASA Astrophysics Data System (ADS)

    Rapalini, A. E.; Calderón, M.; Singer, S.; Hervé, F.; Cordani, U.

    2008-06-01

    A paleomagnetic study was carried out on the Late Jurassic Sarmiento Ophiolitic Complex (SOC) exposed in the Magallanes fold and thrust belt in the southern Patagonian Andes (southern Chile). This complex, mainly consisting of a thick succession of pillow-lavas, sheeted dikes and gabbros, is a seafloor remnant of the Late Jurassic to Early Cretaceous Rocas Verdes basin that developed along the south-western margin of South America. Stepwise thermal and alternating field demagnetization permitted the isolation of a post-folding characteristic remanence, apparently carried by fine grain (SD?) magnetite, both in the pillow-lavas and dikes. The mean "in situ" direction for the SOC is Dec: 286.9°, Inc: - 58.5°, α95: 6.9°, N: 11 (sites). Rock magnetic properties, petrography and whole-rock K-Ar ages in the same rocks are interpreted as evidence of correlation between remanence acquisition and a greenschist facies metamorphic overprint that must have occurred during latest stages or after closure and tectonic inversion of the basin in the Late Cretaceous. The mean remanence direction is anomalous relative to the expected Late Cretaceous direction from stable South America. Particularly, a declination anomaly over 50° is suggestively similar to paleomagnetically interpreted counter clockwise rotations found in thrust slices of the Jurassic El Quemado Fm. located over 100 km north of the study area in Argentina. Nevertheless, a significant ccw rotation of the whole SOC is difficult to reconcile with geologic evidence and paleogeographic models that suggest a narrow back-arc basin sub-parallel to the continental margin. A rigid-body 30° westward tilting of the SOC block around a horizontal axis trending NNW, is considered a much simpler explanation, being consistent with geologic evidence. This may have occurred as a consequence of inverse reactivation of old normal faults, which limit both the SOC exposures and the Cordillera Sarmiento to the East. The age of tilting is unknown but it must postdate remanence acquisition in the Late Cretaceous. Two major orogenic events of the southern Patagonian Andes, in the Eocene (ca. 42 Ma) and Middle Miocene (ca. 12 Ma), respectively, could have caused the proposed tilting.

  13. Lateral extrusion of Tunisia : Contribution of Jeffara Fault (southern branch) and Petroleum Implications

    NASA Astrophysics Data System (ADS)

    Ghedhoui, R.; Deffontaines, B.; Rabia, M. C.

    2012-04-01

    Contrasting to the northward African plate motion toward Eurasia and due to its geographic position in the North African margin, since early cretaceous, Tunisia seems to be submitted to an eastward migration. The aim of this work is to study the southern branch of this inferred tectonic splay that may guide the Tunisian extrusion characterised to the east by the Mediterranean sea as a free eastern boundary. The Jeffara Fault zone (southern Tunisia), represent a case example of such deformation faced by Tunisia. Helped by the results of previous researchers (Bouaziz, 1995 ; Rabiaa, 1998 ; Touati et Rodgers, 1998 ; Sokoutis D. et al., 2000 ; Bouaziz et al., 2002 ; Jallouli et al., 2005 ; Deffontaines et al., 2008…), and new evidences developed in this study, we propose a geodynamic Tunisian east extrusion model, due to such the northern African plate migration to the Eurasian one. In this subject, structural geomorphology is undertaken herein based on both geomorphometric drainage network analysis (Deffontaines et al., 1990), the Digital Terrain Model photo-interpretation (SRTM) combined with photo-interpretation of detailed optical images (Landsat ETM+), and confirmed by field work and numerous seismic profiles at depth. All these informations were then integrated within a GIS (Geodatabase) (Deffontaines 1990 ; Deffontaines et al. 1994 ; Deffontaines, 2000 ; Slama, 2008 ; Deffontaines, 2008) and are coherent with the eastern extrusion of the Sahel block. We infer that the NW-SE Gafsa-Tozeur, which continue to the Jeffara major fault zone acting as a transtensive right lateral motion since early cretaceous is the southern branch of the Sahel block extrusion. Our structural analyses prove the presence of NW-SE right lateral en-echelon tension gashes, NW-SE aligned salt diapirs, numerous folds offsets, en-echelon folds, and so on that parallel this major NW-SE transtensive extrusion fault zone.These evidences confirm the fact that the NW-SE Jeffara faults correspond to the tectonic accident, located in the south of the Tunisian extrusion, in favour of the eastern migration of the Sahel block toward the free Mediterranean sea boundary. Therefore this geodynamic movement explains the presence, in offshore area, of small elongated NW-SE, N-S &NE-SW petroleum transtensive basins and grabens. To conclude, at the regional scale, the structural geomorphologic approach combined with both field work and reflexion seismic profile analyses appear to be an excellent tool to prove & confirm the east Sahel block extrusion of the central Tunisian part caused by the northward migration of African plate. _______________________________________ Keywords : Geodynamics, Neotectonics, right lateral transtensive fault, Extrusion, Petroleum exploration, Geomorphometry, Digital Elevation Model, Geographic Information System (GIS), Geodatabase, Jeffara, South Tunisia.

  14. Three-dimensional P and S wave velocity structures of southern Peru and their tectonic implications

    NASA Technical Reports Server (NTRS)

    Cunningham, Paul S.; Roecker, Steven W.; Hatzfeld, Denis

    1986-01-01

    Arrival times of compressional and shear (S) waves from microearthquakes recorded in 1981 by an 18-station regional array are used to study the three-dimensional velocity structure of the crust and upper mantle of the central Andes. The data suggest a crustal thickness of about 40 km beneath the coast, increasing to about 70 km beneath the Cordillera Occidental. The inverse correlation between the dip in the Moho and the dip of the slab may indicate a broad-scale causal relation between the two. S wave velocities in the mantle between 70 and 130 km depth above the 30-degree dipping slab are low, possibly indicating the presence of a partially melted asthenosphere that may be responsible for the magmatic activity recorded in southern Peru.

  15. Intradomiciliary behavior of Anopheles albimanus on the coastal plain of southern Mexico: implications for malaria control.

    PubMed

    Bown, D N; Rodriguez, M H; Arredondo-Jimenez, J I; Loyola, E G; Rodriguez, M C

    1993-09-01

    The postfeeding indoor resting behavior of Anopheles albimanus in experimental houses in southern México was investigated by using a mark-recapture procedure. The majority of mosquitoes rested inside houses after taking a blood meal indoors. There was a higher landing frequency on interior surfaces other than walls and roofs; however, mosquitoes rested for longer periods on these 2 surfaces. Successive landings on walls after short flights showed that mosquitoes gradually increased their mean landing height from 1.0 to 1.4 m. Similarly, mosquitoes resting at the base of inner roofs had a successive landing height range of about 0.5 m. Based on these observations and the potential for reduction of nearly 50% in the quantity of insecticide used and the time needed to apply it, village-scale studies involving the selective spraying of a 1-m-wide swath of insecticide on walls and on roofs are recommended in this area. PMID:8245943

  16. Structural and Geologic Mapping of Southern Tellus Regio, Venus: Implications for Crustal Plateau Formation

    NASA Astrophysics Data System (ADS)

    Graupner, Melanie

    Crustal plateau formation on Venus is subject to animated debate, centered on plateau support and resulting surface deformation. Detailed mapping provides critical clues for plateau evolution. Southern Tellus Regio records broadly synchronous formation of contractional and extensional structures, accompanied by deposition of flood material. Short-wavelength folds occur across the entire plateau, the extent of which has previously been undocumented. Generally the early-formed structures record a high structural fluidity, marked by variable orientation of structures or juxtaposition of neighboring structural suites. This interpretation of the geologic history of the region indicates the necessity of an extremely high geothermal gradient and provides a means to evaluate the different crustal plateau hypotheses. The mantle downwelling, mantle upwelling, and pulsating continents hypotheses fail to accommodate the surface features recorded in this study. However, the lava pond hypothesis provides a suitable hypothesis of crustal plateau formation that accommodates structural elements recorded in this study.

  17. Prediction of temperature and precipitation in Sudan and South Sudan by using LARS-WG in future

    NASA Astrophysics Data System (ADS)

    Chen, Hua; Guo, Jiali; Zhang, Zengxin; Xu, Chong-Yu

    2013-08-01

    Global warming has brought great pressure on the environment and livelihood conditions in Sudan and South Sudan. It is desirable to analyze and predict the change of critical climatic variables, such as temperature and precipitation, which will provide valuable reference results for future water resources planning and management in the region. The aims of this study are to test the applicability of the Long Ashton Research Station Weather Generator (LARS-WG) model in downscaling daily precipitation and daily maximum (Tmax) and daily minimum (Tmin) temperatures in Sudan and South Sudan and use it to predict future changes of precipitation; Tmin and Tmax for nine stations in Sudan and South Sudan are based on the SRA2 scenario of seven General Circulation Models (GCMs) outputs for the periods of 2011-2030, 2046-2065, and 2080-2099. The results showed that (1) the LARS-WG model produces good performance in downscaling daily precipitation and excellent performance in downscaling Tmax and Tmin in the study region; (2) downscaled precipitation from the prediction of seven GCMs showed great inconsistency in these two regions, which illustrates the great uncertainty in GCMs' results in the regions; (3) predicted precipitation in rainy season JJA (June, July, and August) based on the ensemble mean of seven GCMs showed a decreasing trend in the periods of 2011-2030, 2046-2065, and 2080-2099 in Sudan; however, an increasing trend can be found in SON (September, October, and November) in the future; (4) precipitation in South Sudan has an increasing trend in most seasons in the future except in MAM (March, April, and May) season in 2011-2030; and (5) predictions from seven GCMs showed a similar and continuous increasing trend for Tmax and Tmin in all three future periods, which will bring severe negative influence on improving livelihoods and reducing poverty in Sudan and South Sudan.

  18. Anthocyanins of Hibiscus sabdiffera calyces from Sudan.

    PubMed

    Cahliková, Lucie; Ali, Badreldin H; Havliková, Lucie; Ločárek, Mirek; Siatka, Tomáš; Opletal, Lubomir; Blunden, Gerald

    2015-01-01

    Extracts of the calyces of Hibiscus sabdariffa are widely used in folk medicine to combat many illnesses. The active constituents of the extracts have been shown on several occasions to be anthocyanins. In our current studies the biological activities of an extract of H. sabdariffa calyces purchased in Oman, but grown in Sudan, are being compared with those of the anthocyanins isolated from them, and, for this, the anthocyanin profile of the extract needed to be ascertained. Although several anthocyanins were detected by UHPLC-ESI-MS/MS, delphinidin-3-sambubioside (major) and cyanidin-3-sambubioside were predominant. PMID:25920224

  19. Meteorologic and isotopic characteristics of precipitation events with implications for groundwater recharge, Southern High Plains

    NASA Astrophysics Data System (ADS)

    Nativ, Ronit; Riggio, Robert

    Recharge estimates for the Ogallala aquifer in the Southern High Plains vary by two orders of magnitude (0.01 to 1.6 inches/yr or 0.25 to 41 mm/yr) because of differing interpretations of the contribution of the area's numerous playa lakes to the recharge of the aquifer. Higher rates are suggested by studies in which the playa lakes are assumed to be a major source of recharge. To reevaluate the recharge potential of precipitation, we measured meteorologic and isotopic properties of single precipitation events at five stations for one year. Values of precipitation for δ 18O (-22.7‰ to -4.7‰) and δD (-162% to +35%) plot along the world meteoric water line. Mean annual weighted values of δ 18O and δD are -7.5‰ and -48‰, respectively. Air masses from the Gulf of Mexico account for most summer precipitation, which is more isotopically enriched than winter precipitation, mainly derived from air masses from the eastern Pacific Ocean. Precipitation is more depleted in δ 18O and δD toward the northwestern part of the Southern High Plains, becoming isotopically enriched toward the southeast. These isotopic differences reflect temperature, continental, and altitude effects. Isotopic composition of Ogalla ground water has a spatial distribution similar to that of precipitation. Ground water, however, is consistently more enriched than precipitation sampled in the same area, suggesting evaporation during recharge. Evaporation can occur either in playa lakes prior to infiltration or in the vadose zone. Tritium in precipitation ranges from 1.1 to 14.7 TU, and in groundwater it ranges from zero where the vadose zone is thick, to 73 TU, where the zone is thin. The calculated recharge rate (using tritium as a tracer) ranges from 0.5 to 3.24 inches/yr, or 12.7 to 82 mm/yr. Such high recharge rates were only measured below playa lakes. Because of the fast recharge rates and the slightly enriched values of δ 18O and δD in ground water, the Ogalla a aquifer is most likely recharged by focused percolation of partly evaporated playa lake water, rather than by slow regional diffusive percolation of precipitation.

  20. Climate variability and El Niño Southern Oscillation: implications for natural coastal resources and management

    NASA Astrophysics Data System (ADS)

    Thatje, Sven; Heilmayer, Olaf; Laudien, Jürgen

    2008-03-01

    The El Niño Southern Oscillation (ENSO) significantly influences marine ecosystems and the sustained exploitation of marine resources in the coastal zone of the Humboldt Current upwelling system. Both its warm (El Niño: EN) and cold (La Niña: LN) phase have drastic implications for the ecology, socio-economy and infrastructure along most of Pacific South America. Local artisanal fisheries, which especially suffer from the effects of EN, represent a major part for the domestic economy of Chile and Peru and in consequence a huge amount of published and unpublished studies exists aiming at identifying effects of EN and LN. However, most processes and underlying mechanisms fostering the ecology of organisms along Pacific South America have not been analyzed yet and for the marine realm most knowledge is traditionally based on rather descriptive approaches. We herein advocate that small-scale comparative and interdisciplinary process studies work as one possible solution to understand better the variability observed in EN/LN effects at local scale. We propose that differences in small-scale impacts of ENSO along the coast rather than the macro-ecological and oceanographic view are essential for the sustainable management of costal ecosystems and the livelihood of the people depending on it. Based on this, we summarize the conceptual approach from the EU-funded International Science and Technology Cooperation (INCO) project “Climate variability and El Niño Southern Oscillation: Implications for Natural Coastal Resources and Management (CENSOR)” that aims at enhancing the detection, compilation, and understanding of EN and LN effects on the coastal zone and its natural resources. We promote a multidisciplinary avenue within present international funding schemes, with the intention to bridge the traditional gap between basic and applied coastal research. The long-term aim is an increased mitigation of harm caused by EN as well as a better use of beneficial effects, with the possibility to improve the livelihood of human coastal populations along Pacific South America and taking differences between local socio-economic structures of the countries affected by EN into consideration. The success of such an approach however, does finally rely upon a willingness of the recourse users and the various political and economic stakeholders involved to taking on the message as part of sustainable management strategies.

  1. Holocene Pacific North American plate interaction in southern Alaska: Implications for the Yakataga seismic gap

    NASA Astrophysics Data System (ADS)

    Lahr, John C.; Plafker, George

    1980-10-01

    The St. Elias, Alaska, earthquake (magnitude 7.1 Ms) on February 28, 1979, occurred along the complex Pacific North American plate boundary between Yakutat Bay and Prince William Sound, rupturing only a fraction of the seismic gap identified in that region. To aid in evaluating the potential for, and likely site of, a future earthquake occurring in the remainder of the gap, we have formulated a kinematic model of neotectonic deformation in southern Alaska from available geologic and seismic data. In this model the part of the North American plate bordering on the Gulf of Alaska is divided into three subblocks, which are partially coupled to the Pacific plate. On the basis of the model, the gap-filling rupture or ruptures would most likely be along the north-dipping thrust faults of the Pamplona zone between Icy Bay and the eastern end of the Aleutian Trench. If the accumulated strain of 3.8 m postulated for this region were released suddenly in one event involving the remainder of the gap, the result would be an earthquake as large as magnitude 8.

  2. Subsidence and thermal history of Southern Oklahoma aulacogen: implications for petroleum exploration

    SciTech Connect

    Feinstein, S.

    1981-12-01

    Reconstructed subsidence curves and the thermal history of the Southern Oklahoma aulacogen support the concept of thermally controlled isostatic subsidence for the formation of the basin and indicate the significance of this concept for petroleum exploration. Two mechanisms - initial elastic flexure, followed by detachment and differential subsidence of the aulacogen - are inferred from the subsidence curves. Two methods have been used for reconstruction of the thermal history. A tectonophysics model in combination with a history of basin evolution demonstrates that geothermal gradient and depth-of-burial were dynamic variables during the subsidence stage; maximum paleotemperatures were attained during Sylvan (Late Ordovician) time near the close of subsidence; and most of the Arbuckle Group had been subjected to the temperature conditions of oil formation (the oil liquid window) prior to the possible phase of fluid migration in Sylvan time. The second method, involving reconstruction of the geothermal history on the basis of geothermometry (palynomorph carbonization), suggests: (1) paleotemperatures exerted a significant effect on the level of organic metamorphism in the sedimentary rocks; (2) the geothermal gradient varied during the subsidence stage; (3) paleotemperatures were higher than those predicted by the theoretical model and support the hypothesis of formation of the basin by thermally controlled subsidence, and the application of this concept for petroleum exploration.

  3. Clinical and pharmacogenomic implications of genetic variation in a Southern Ethiopian population.

    PubMed

    Tekola-Ayele, F; Adeyemo, A; Aseffa, A; Hailu, E; Finan, C; Davey, G; Rotimi, C N; Newport, M J

    2015-02-01

    Africa is home to genetically diverse human populations. We compared the genetic structure of the Wolaita ethnic population from Southern Ethiopia (WETH, n=120) with HapMap populations using genome-wide variants. We investigated allele frequencies of 443 clinically and pharmacogenomically relevant genetic variants in WETH compared with HapMap populations. We found that WETH were genetically most similar to the Kenya Maasai and least similar to the Japanese in HapMap. Variant alleles associated with increased risk of adverse reactions to drugs used for treating tuberculosis (rs1799929 and rs1495741 in NAT2), thromboembolism (rs7294, rs9923231 and rs9934438 in VKORC1), and HIV/AIDS and solid tumors (rs2242046 in SLC28A1) had significantly higher frequencies in WETH compared with African ancestry HapMap populations. Our results illustrate that clinically relevant pharmacogenomic loci display allele frequency differences among African populations. We conclude that drug dosage guidelines for important global health diseases should be validated in genetically diverse African populations. PMID:25069476

  4. Holocene Pacific - North American plate interaction in southern Alaska: implications for the Yakataga seismic gap.

    USGS Publications Warehouse

    Lahr, J.C.; Plafker, G.

    1980-01-01

    The St. Elias, Alaska, earthquake (magnitude 7.1 MS) on February 28, 1979, occurred along the complex Pacific-North American plate boundary between Yakutat Bay and Prince William Sound, rupturing only a fraction of the seismic gap identified in that region. To aid in evaluating the potential for, and likely site of, a future earthquake occurring in the remainder of the gap, we have formulated a kinematic model of neotectonic deformation in southern Alaska from available geologic and seismic data. In this model the part of the North American plate bordering on the Gulf of Alaska is divided into three subblocks, which are partially coupled to the Pacific plate. On the basis of the model, the gap-filling rupture or ruptures would most likely be along the north-dipping thrust faults of the Pamplona zone between Icy Bay and the eastern end of the Aleutian Trench. If the accumulated strain of 3.8 m postulated for this region were released suddenly in one event involving the remainder of the gap, the result would be an earthquake as large as magnitude 8. -Authors

  5. Intradomicillary pre- and postfeeding behavior of Anopheles pseudopunctipennis of southern Mexico: implications for malaria control.

    PubMed

    Casas, M; Bown, D N; Rodríguez, M H

    1994-09-01

    The intradomicillary pre- and postfeed resting behavior of Anopheles pseudopunctipennis was studied in an experimental house in southern Mexico. During resting periods (both pre-/postfeed) mosquitos had greater contact (landings) with the inner roof than with the walls and other surfaces. A comparison of mean landing frequency and overall resting time (pre-/postfeed) showed that a greater periodic and prolonged contact occurred prefeed, probably as a result of disturbed activity associated with host movements. Pre-/postfeed resting patterns on walls were limited to a 0.6-0.5-m-wide band, nearly 1 m from the floor, and to a narrower band on the roof, 0.3-0.2 m wide, approximately 2.3 m from the floor, respectively. We calculated that with a band width of 0.8 m on the walls and another band 0.8 m wide on the roof, 87.2% of the mosquitoes had at least one contact with either the wall, the roof, or with both surfaces, along with an overall mean resting time (pre-/postfeed) of 8.1 min/landing. These findings suggest that a high potential for control can be achieved by spraying preferred wall and roof resting sites in this region where the intradomicillary application of residual insecticide is the primary malaria control measure. PMID:7807076

  6. Avian influenza A viruses of southern China and Hong Kong: ecological aspects and implications for man*

    PubMed Central

    Shortridge, K. F.

    1982-01-01

    Continuous surveillance of the influenza viruses isolated from domestic poultry from southern China and Hong Kong over more than 4 years resulted in the isolation of influenza viruses possessing 46 different combinations of haemagglutinin (H) and neuraminidase (N) subtypes. Of these, 43 were obtained from ducks from China. In all cases, infection appeared to be asymptomatic. The antigenic combination found most commonly in the viruses isolated was H4N6, which accounted for approximately one-quarter of the duck isolates, its occurrence being more frequent than expected from a statistical analysis of the observed frequencies of the haemagglutinin and neuraminidase genes among all the isolates. Some combinations of H and N occurred less frequently than expected or not at all. Influenza viruses tended to be isolated more frequently from ducks during the summer months in comparison with paramyxoviruses, which were more commonly encountered in the winter. Possible reasons for the great antigenic diversity of influenza A viruses in the poultry, especially the ducks, in the region are discussed together with the potential significance of these viruses to the emergence of human influenza pandemics. PMID:6979416

  7. Folklore and traditional ecological knowledge of geckos in Southern Portugal: implications for conservation and science.

    PubMed

    Ceríaco, Luis M P; Marques, Mariana P; Madeira, Natália C; Vila-Viçosa, Carlos M; Mendes, Paula

    2011-01-01

    Traditional Ecological Knowledge (TEK) and folklore are repositories of large amounts of information about the natural world. Ideas, perceptions and empirical data held by human communities regarding local species are important sources which enable new scientific discoveries to be made, as well as offering the potential to solve a number of conservation problems. We documented the gecko-related folklore and TEK of the people of southern Portugal, with the particular aim of understanding the main ideas relating to gecko biology and ecology. Our results suggest that local knowledge of gecko ecology and biology is both accurate and relevant. As a result of information provided by local inhabitants, knowledge of the current geographic distribution of Hemidactylus turcicus was expanded, with its presence reported in nine new locations. It was also discovered that locals still have some misconceptions of geckos as poisonous and carriers of dermatological diseases. The presence of these ideas has led the population to a fear of and aversion to geckos, resulting in direct persecution being one of the major conservation problems facing these animals. It is essential, from both a scientific and conservationist perspective, to understand the knowledge and perceptions that people have towards the animals, since, only then, may hitherto unrecognized pertinent information and conservation problems be detected and resolved. PMID:21892925

  8. UAVSAR and GPS Observations of Crustal Deformation in Southern California and Implications for Earthquake Risk

    NASA Astrophysics Data System (ADS)

    Donnellan, A.; Parker, J. W.; Lyzenga, G. A.; Rundle, J. B.; Grant Ludwig, L.; Granat, R. A.; Glasscoe, M. T.; Heflin, M. B.

    2010-12-01

    The 2010 El-Mayor Cucapah earthquake was the first earthquake to be observed with UAVSAR. UAVSAR observations, GPS time series analysis, and simulations suggest that the fault that ruptured in the earthquake is coupled to the Elsinore, San Jacinto, and San Andreas faults to the north. GPS and UAVSAR observations indicate a zone of shear that extends southward from the Big Bend of the San Andreas fault near Gorman through the San Fernando Valley towards the Newport-Inglewood fault. The zone steps over to the region of the Elsinore or San Jacinto faults, though the partitioning of strain between the two faults is not as clear. State changes in GPS time series data fall in line with the shear zone through the San Fernando Valley and extend northward from the El Mayor-Cucapah earthquake rupture. Seismicity hotspots also indicate elevated earthquake hazard near the San Fernando Valley and in the Inland Empire near the Elsinore and San Jacinto faults. Inversions of GPS velocity vectors favor a fault underlying the shear zone extending from the Big Bend to the Newport-Inglewood fault over substantial slip on the San Andreas fault under north of Los Angeles. Virtual California simulations of southern California are being analyzed for fault activity associated with the identified shear zone and for subsequent earthquakes that may be related to El Mayor-Cucapah type earthquakes in Baja.

  9. Shear-wave splitting beneath southern Korea and its tectonic implication

    NASA Astrophysics Data System (ADS)

    Kang, Tae-Seob; Shin, Jin Soo

    2009-06-01

    Seismic anisotropy beneath the southern Korean Peninsula (SKP) was investigated based on the ScS waves of deep-focused earthquakes recorded at 35 broadband stations. The most striking feature of the observed splitting patterns is the preference of the fast directions (NW-SE) that are nearly parallel to the direction of the absolute plate motion in the region. However, the splitting patterns over the region show significant variation in splitting parameters indicating a complex anisotropic structure. Variations of the splitting directions and dissimilarity in the source domains of basaltic volcanisms suggest that the asthenospheric mantle flow since at least the late Cenozoic cannot explain the seismic anisotropy beneath the region. Comparison to shear-wave splitting measurements from eastern China revealed that the NW-SE fast direction of splitting measurements in the SKP is close to that in the North China block (NCB) while the NE-SW fast direction might be related to that in the South China block (SCB). The shallow mantle lithosphere beneath the SKP retains the fossil anisotropy amalgamated prior to the late Paleozoic before the collision between the NCB and SCB, and the anisotropic structure was not completely realigned by the major orogenic events during the late Paleozoic to Mesozoic eras.

  10. Spatial variation in seabed temperatures in the Southern Ocean: Implications for benthic ecology and biogeography

    NASA Astrophysics Data System (ADS)

    Clarke, Andrew; Griffiths, Huw J.; Barnes, David K. A.; Meredith, Michael P.; Grant, Susie M.

    2009-09-01

    The Antarctic seabed has traditionally been regarded as cold and thermally stable, with little spatial or seasonal variation in temperature. Here we demonstrate marked spatial variations in continental shelf seabed temperature around Antarctica, with the western Antarctic Peninsula shelf significantly warmer than shelves around continental Antarctica as a result of flooding of the shelf by Circumpolar Deep Water from the Antarctic Circumpolar Current. The coldest shelf seabed temperatures are in the Weddell Sea, Ross Sea, and Prydz Bay as a consequence of seasonal convection associated with strong air-sea heat fluxes and sea-ice formation. These waters constitute the dense precursors of Antarctic Bottom Water, and can descend down the adjacent slope to inject cold water into the Southern Ocean deep sea. Deep sea seabed temperatures are coldest in the Weddell Sea and are progressively warmer to the east. There is a distinct latitudinal gradient in the difference between seabed temperatures on the shelf and in the deep sea, with the deep sea warmer by up to ˜2 K at high latitudes and colder by ˜2 K around sub-Antarctic islands. These differences have important consequences for benthic ecology and biogeography, understanding the evolutionary history of the Antarctic marine biota, and the impact of regional climate change.

  11. Folklore and traditional ecological knowledge of geckos in Southern Portugal: implications for conservation and science

    PubMed Central

    2011-01-01

    Traditional Ecological Knowledge (TEK) and folklore are repositories of large amounts of information about the natural world. Ideas, perceptions and empirical data held by human communities regarding local species are important sources which enable new scientific discoveries to be made, as well as offering the potential to solve a number of conservation problems. We documented the gecko-related folklore and TEK of the people of southern Portugal, with the particular aim of understanding the main ideas relating to gecko biology and ecology. Our results suggest that local knowledge of gecko ecology and biology is both accurate and relevant. As a result of information provided by local inhabitants, knowledge of the current geographic distribution of Hemidactylus turcicus was expanded, with its presence reported in nine new locations. It was also discovered that locals still have some misconceptions of geckos as poisonous and carriers of dermatological diseases. The presence of these ideas has led the population to a fear of and aversion to geckos, resulting in direct persecution being one of the major conservation problems facing these animals. It is essential, from both a scientific and conservationist perspective, to understand the knowledge and perceptions that people have towards the animals, since, only then, may hitherto unrecognized pertinent information and conservation problems be detected and resolved. PMID:21892925

  12. Tephrochronology of a 72 ka-long marine record: implications for the southern Tyrrhenian explosive volcanism

    NASA Astrophysics Data System (ADS)

    Tamburrino, Stella; Insinga, Donatella; Pelosi, Nicola; Kissel, Catherine; Laj, Carlo; Capotondi, Lucilla; Sprovieri, Mario

    2015-04-01

    Several discrete tephra layers occur in a Marion Dufresne 13.9 m-long deep-sea core (MD01-2474G) from the southern Tyrrhenian Sea. Major, minor and trace element data (EMPA-WDS and LA-ICP-MS analyses) from fresh micro-pumices and glass shards allow to correlate them with the volcanic activity from Aeolian Islands (Lipari, Vulcano, Salina), Campanian Plain (Ischia), Pantelleria and Mt. Etna. The chronology of the succession is provided by a high-resolution age-model based on isotope stratigraphy and AMS radiocarbon dating, which places the succession in a time interval spanning the last 72 kyrs BP. According to a detailed proximal-distal and distal-distal correlation, a precise chronological framework is established and some main markers tephras of the central Mediterranean area (Y-1, Y-6, Y-7 and Y-8) are recognised. In additions, the succession is a precious archive to record multiple volcanic events occurred at Ischia volcano and the Aeolian Arc (Lipari and Vulcano). This latter, in particular, erupted several products which exhibits strong compositional variations otherwise non detectable from terrestrial counterparts. The results of the present study, hence, provide new data for a detailed analytical reference database of the Tyrrhenian Sea tephrochronology and may contribute to a better chronostratigraphic reconstruction of the Aeolian arc explosive events.

  13. River channel adjustments in Southern Italy over the past 150 years and implications for channel recovery

    NASA Astrophysics Data System (ADS)

    Scorpio, Vittoria; Aucelli, Pietro P. C.; Giano, Salvatore I.; Pisano, Luca; Robustelli, Gaetano; Rosskopf, Carmen M.; Schiattarella, Marcello

    2015-12-01

    Multi-temporal GIS analysis of topographic maps and aerial photographs along with topographic and geomorphological surveys are used to assess evolutionary trends and key control factors of channel adjustments for five major rivers in southern Italy (the Trigno, Biferno, Volturno, Sinni and Crati rivers) to support assessment of channel recovery and river restoration. Three distinct phases of channel adjustment are identified over the past 150 years primarily driven by human disturbances. Firstly, slight channel widening dominated from the last decades of the nineteenth century to the 1950s. Secondly, from the 1950s to the end of the 1990s, altered sediment fluxes induced by in-channel mining and channel works brought about moderate to very intense incision (up to 6-7 m) accompanied by strong channel narrowing (up to 96%) and changes in channel configuration from multi-threaded to single-threaded patterns. Thirdly, the period from around 2000 to 2015 has been characterized by channel stabilization and local widening. Evolutionary trajectories of the rivers studied are quite similar to those reconstructed for other Italian rivers, particularly regarding the second phase of channel adjustments and ongoing transitions towards channel recovery in some reaches. Analyses of river dynamics, recovery potential and connectivity with sediment sources of the study reaches, framed in their catchment context, can be used as part of a wider interdisciplinary approach that views effective river restoration alongside sustainable and risk-reduced river management.

  14. Short communication: new HIV infections at Southern New England academic institutions: implications for prevention.

    PubMed

    Chan, Philip A; Kazi, Shahzeb; Rana, Amaad; Blazar, Ilyse; Dejong, Colette C; Mayer, Kenneth H; Huard, Thomas K; Carleton, Kim; Gillani, Fizza; Alexander, Nicole; Parillo, Zoanne; Flanigan, Timothy P; Kantor, Rami

    2013-01-01

    New HIV infections among younger men who have sex with men (MSM) in the United States are escalating. Data on HIV infections in college students are limited. In 2010, three MSM college students presented to our clinic with primary HIV infection (PHI) in a single month. To determine the number of college students among new HIV diagnoses, we reviewed clinical characteristics and molecular epidemiology of HIV-diagnosed individuals from January to December 2010 at the largest HIV clinic in Southern New England. PHI was defined as acute HIV infection or seroconversion within the last 6 months. Of 66 individuals diagnosed with HIV in 2010, 62% were MSM and 17% were academic students (12% college or university, 5% other). Seventy-three percent of students were MSM. Compared to nonstudents, students were more likely to be younger (24 versus 39 years), born in the United States (91% versus 56%), have another sexually transmitted disease (45% versus 11%), and present with PHI (73% versus 16%, all p-values<0.05). Thirty percent of individuals formed eight transmission clusters including four students. MSM were more likely to be part of clusters. Department of Health contact tracing of cluster participants allowed further identification of epidemiological linkages. Given these high rates of PHI in recently diagnosed students, institutions of higher education should be aware of acute HIV presentation and the need for rapid diagnosis. Prevention strategies should focus on younger MSM, specifically college-age students who may be at increased risk of HIV infection. PMID:22724920

  15. Environmental and Archaeological Implications of a Late Quaternary Palynological Sequence, Poyang Lake, Southern China

    NASA Astrophysics Data System (ADS)

    Jiang, Qinhua; Piperno, Dolores R.

    1999-09-01

    Paleoecological data from Poyang Lake, southern China, indicate that significant natural and human-induced vegetational changes have occurred during the Late Quaternary in the Middle Yangtze River valley, the likely location of rice (Oryza sativa L.) domestication. During the late Pleistocene (from ca. 12,830 to ca. 10,500 yr B.P.), the climate was cooler and drier than today's. The subtropical, mixed deciduous-evergreen broad-leaved forest which constitutes the modern, potential vegetation was reduced and herbaceous vegetative cover expanded. A hiatus in sedimentation occurred in Poyang Lake, beginning sometime after ca. 10,500 yr B.P. and lasting until the middle Holocene (ca. 4000 yr B.P.). At ca. 4000 yr B.P., the regional vegetation was a diverse, broad-leaved forest dominated by many of the same arboreal elements (e.g., Quercus, Castanopsis, Liquidambar) that grow in the area today. A significant reduction of arboreal pollen and an increase of herbaceous pollen at ca. 2000 yr B.P. probably reflect human influence on the vegetation and the expansion of intensive rice agriculture into the dryland forests near the river valleys.

  16. Seismic chimneys in the Southern Viking Graben - Implications for palaeo fluid migration and overpressure evolution

    NASA Astrophysics Data System (ADS)

    Karstens, Jens; Berndt, Christian

    2015-02-01

    Detailed understanding of natural fluid migration systems is essential to minimize risks during hydrocarbon exploration and to evaluate the long-term efficiency of the subsurface storage of waste water and gas from hydrocarbon production as well as CO2. The Southern Viking Graben (SVG) hosts numerous focused fluid flow structures in the shallow (<1000 m) subsurface. The seismic expressions of vertical fluid conduits are variously known as seismic chimneys or pipes. Seismic pipes are known to form large clusters. Seismic chimneys have so far been described as solitary structures. Here, we show that the study area in the SVG hosts more than 46 large-scale vertical chimney structures, which can be divided in three categories implying different formation processes. Our analysis reveals that seal-weakening, formation-wide overpressure and the presence of free gas are required to initiate the formation of vertical fluid conduits in the SVG. The presence of numerous vertical fluid conduits implies inter-stratigraphic hydraulic connectivity, which significantly affects the migration of fluids in the subsurface. Chimney structures are important for understanding the transfer of pore pressure anomalies to the shallow parts of the basin.

  17. Snow-avalanche impact landforms in Breheimen, southern Norway: Origin, age, and paleoclimatic implications

    SciTech Connect

    Matthews, J.A.; McCarroll, D. )

    1994-05-01

    Twelve snow-avalanche ramparts in Jostedalen and Sprongdalen (Breheimen, southern Norway) are investigated to elucidate processes of formation, the history of avalanche activity, and their potential for paleoclimatic reconstruction. Variation in the form of these riverbank boulder ramparts reflects local patterns of avalanche impact. Differences in clast roundness between ramparts, avalanche tracks, and river beds indicate that, on average, 50 to 60% of the clasts in the ramparts originate from river bedload as opposed to avalanche source areas or tracks. Rampart clasts increase in roundness downstream over a distance of 12 km, and the contribution from the river bed varies from 26 to 80% depending on local factors. Conventional lichenometric dating suggests ages for the initiation of rampart formation of 250 to 2000 yr, but they probably have a much longer history. Lichen-size frequency distributions, using the largest lichen from each of n boulders, reflect the age-frequency of surface boulders, providing a record of late Holocene avalanche activity. A simulation model suggests that maximum avalanche activity affected nine of the ramparts during the 19th century, after the peak of the Little Ice Age. The pattern of avalanche activity differs from the pattern of glacier variations but is in close agreement with that of debris-flow activity. The ramparts may yield a valuable proxy record of winter snowfall. 48 refs., 12 figs., 4 tabs.

  18. Dental microwear of sympatric rodent species sampled across habitats in southern Africa: Implications for environmental influence.

    PubMed

    Burgman, Jenny H E; Leichliter, Jennifer; Avenant, Nico L; Ungar, Peter S

    2016-03-01

    Dental microwear textures have proven to be a valuable tool for reconstructing the diets of a wide assortment of fossil vertebrates. Nevertheless, some studies have recently questioned the efficacy of this approach, suggesting that aspects of habitat unrelated to food preference, especially environmental grit load, might have a confounding effect on microwear patterning that obscures the diet signal. Here we evaluate this hypothesis by examining microwear textures of 3 extant sympatric rodent species that vary in diet breadth and are found in a variety of habitat types: Mastomys coucha, Micaelamys namaquensis and Rhabdomys pumilio. We sample each of these species from 3 distinct environmental settings in southern Africa that differ in rainfall and vegetative cover: Nama-Karoo shrublands (semi-desert) and Dry Highveld grasslands in the Free State Province of South Africa, and Afromontane (wet) grasslands in the highlands of Lesotho. While differences between habitat types are evident for some of the species, inconsistency in the pattern suggests that the microwear signal is driven by variation in foods eaten rather than grit-level per se. It is clear that, at least for species and habitats sampled in the current study, environmental grit load does not swamp diet-related microwear signatures. PMID:26748948

  19. Appearance of De Geer moraines in southern and western Finland - Implications for reconstructing glacier retreat dynamics

    NASA Astrophysics Data System (ADS)

    Ojala, Antti E. K.

    2016-02-01

    LiDAR digital elevation models (DEMs) from southern and western Finland were investigated to map and discriminate features of De Geer moraines, sparser and more scattered end moraines, and larger end moraine features (i.e., ice-marginal complexes). The results indicate that the occurrence and distribution of De Geer moraines and scattered end moraine ridges in Finland are more widespread than previously suggested. This is probably attributed to the ease of detecting and mapping these features with high-resolution DEMs, indicating the efficiency of LiDAR applications in geological and geomorphological studies. The variable appearance and distribution of moraine ridges in Finland support previous interpretations that no single model is likely to be appropriate for the genesis of De Geer moraines at all localities and for all types of end moraines. De Geer moraine appearances and interdistances probably result from a combination of the general rapidity of ice-margin recession during deglaciation, the proglacial water depth in which they were formed, and local glacier dynamics related to climate and terrain topography. The correlation between the varved clay-based rate of deglaciation and interdistances of distinct and regularly spaced De Geer moraine ridges indicates that the rate of deglaciation is probably involved in the De Geer ridge-forming process, but more thorough comparisons are needed to understand the extent to which De Geer interdistances represent an annual rate of ice-margin decay and the rapidity of regional deglaciation.

  20. Conjugate shear zones in the Southern Bohemian Massif (Austria): implications for Variscan and Alpine tectonothermal activity

    NASA Astrophysics Data System (ADS)

    Brandmayr, Michael; Dallmeyer, R. D.; Handler, Robert; Wallbrecher, Eckart

    1995-08-01

    Mylonitic fabrics developed within conjugate wrench ductile shear and fault systems in the Southern Bohemian Massif display both dextral (NW-SE-trending systems) and sinistral (NE-SW-trending systems) shear senses. Contrasting temperature conditions of deformation can be observed in the different shear zones. Temperatures above 650° C were reached in the Pfahl shear zone. Shearing under greenschist facies conditions took place in the Rodl and Danube shear zones. Brittle deformation dominated in the Vitis and Diendorf shear zones. {40Ar}/{39Ar} dating of various size fractions of muscovite formed and/or deformed during mylonitization yield ages of ca. 287 Ma (the NW-SE-trending system) and ca. 288-281 Ma (the NE-SW-trending system). The shear zones are interpreted as a late Variscan conjugate system. {40Ar}/{39Ar} age spectra of fine-grained newly grown sericite or rejuvenation of ages give evidence for post-Variscan reactivation of the shear zones. Brittle deformation within the shear zones was probably associated with maintenance of very high fluid pressure during Variscan deformation. Foreland deformation during the Alpine orogeny also played a significant role, leading not only to the development of the Ceske Budejovice Graben but also to local reactivation of the shear zones at higher crustal levels.

  1. Clinical and Pharmacogenomic Implications of Genetic Variation in a Southern Ethiopian Population

    PubMed Central

    Tekola-Ayele, Fasil; Adeyemo, Adebowale; Aseffa, Abraham; Hailu, Elena; Finan, Chris; Davey, Gail

    2014-01-01

    Africa is home to genetically diverse human populations. We compared the genetic structure of the Wolaita ethnic population from southern Ethiopia (WETH, n=120) with HapMap populations using genome-wide variants. We investigated allele frequencies of 443 clinically and pharmacogenomically relevant genetic variants in WETH compared to HapMap populations. We found that WETH were genetically most similar to the Kenya Maasai and least similar to the Japanese in HapMap. Variant alleles associated with increased risk of adverse reactions to drugs used for treating tuberculosis (rs1799929 and rs1495741 in NAT2), thromboembolism (rs7294, rs9923231 and rs9934438 in VKORC1), and HIV/AIDS and solid tumors (rs2242046 in SLC28A1) had significantly higher frequencies in WETH compared to African ancestry HapMap populations. Our results illustrate that clinically relevant pharmacogenomic loci display allele frequency differences among African populations. We conclude that drug dosage guidelines for important global health diseases should be validated in genetically diverse African populations. PMID:25069476

  2. Floristic Relationships Among Vegetation Types of New Zealand and the Southern Andes: Similarities and Biogeographic Implications

    PubMed Central

    Ezcurra, Cecilia; Baccalá, Nora; Wardle, Peter

    2008-01-01

    Background and Aims Similarities between the floras of geographically comparable regions of New Zealand (NZ) and the southern Andes (SA) have interested biologists for over 150 years. The present work selects vegetation types that are physiognomically similar between the two regions, compares their floristic composition, assesses the environmental factors that characterize these matching vegetation types, and determines whether phylogenetic groups of ancestral versus modern origin are represented in different proportions in their floras, in the context of their biogeographic history. Methods Floristic relationships based on 369 genera of ten vegetation types present in both regions were investigated with correspondence analysis (CA) and ascending hierarchical clustering (AHC). The resulting ordination and classification were related to the environmental characteristics of the different vegetation types. The proportions of different phylogenetic groups between the regions (NZ, SA) were also compared, and between forest and non-forest communities. Key Results Floristic similarities between NZ and SA tend to increase from forest to non-forest vegetation, and are highest in coastal vegetation and bog. The floras of NZ and SA also differ in their phylogenetic origin, NZ being characterized by an ‘excess’ of genera of basal origin, especially in forests. Conclusions The relatively low similarities between forests of SA and NZ are related to the former being largely of in situ South American and Gondwanan origin, whereas the latter have been mostly reconstituted though transoceanic dispersal of propagules since the Oligocene. The greater similarities among non-forest plant communities of the two regions result from varied dispersal routes, including relatively recent transoceanic dispersal for coastal vegetation, possible dispersal via a still-vegetated Antarctica especially for bog plants, and independent immigration from Northern Hemisphere sources for many genera of alpine vegetation and grassland. PMID:18390564

  3. Home management of childhood diarrhoea in southern Mali--implications for the introduction of zinc treatment.

    PubMed

    Ellis, Amy A; Winch, Peter; Daou, Zana; Gilroy, Kate E; Swedberg, Eric

    2007-02-01

    Diarrhoea remains one of the leading killers of young children. A recent meta-analysis demonstrated that a two-week course of zinc tablets once daily significantly reduces the severity and duration of diarrhoea and mortality in young children (Bhutta et al., 2000. Therapeutic effects of oral zinc in acute and persistent diarrhea in children in developing countries: Pooled analysis of randomized controlled trials. American Journal of Clinical Nutrition, 72(6), 1516-1522). Formative research is being conducted in a number of countries to prepare for the large-scale promotion of this new treatment. In-depth and semi-structured interviews with parents, community health workers, and traditional healers were conducted to examine the household management of diarrhoea in the Sikasso region of southern Mali in preparation for the introduction of a short-course of daily zinc for childhood diarrhoea at the community level. Supporting data from a subsequent household survey are also presented. Although nearly all parents knew oral rehydration solution (ORS) could replace lost fluids, its inability to stop diarrhoea caused parents to seek antibiotics from local markets, traditional medicines or anti-malarials to cure the illness. The notion of combining multiple treatments to ensure the greatest therapeutic benefit was prevalent, and modern medicines were often administered simultaneously with traditional therapies. As parents often deem ORS insufficient and judge that an additional treatment should be combined with ORS to cure diarrhoea, the concept of joint therapy of zinc and ORS should be well accepted in the community. Mothers-in-law and fathers, who play a significant role in decisions to seek treatment for sick children, as well as traditional healers, should also be considered when designing new programs to promote zinc. Similarities with formative research conducted for a previous generation of diarrhoea control programmes are discussed. PMID:17097788

  4. Medical education in the Sudan: its strengths and weaknesses.

    PubMed

    Fahal, Ahmed Hassan

    2007-11-01

    The history of medical education in the Sudan is both long and interesting. It began in 1924 and has passed through several different phases and stages. Despite numerous difficulties and constraints along the way, vast experience has been gained and many achievements made, all of which have had positive impacts on the health system in the Sudan and the Region. This paper aims to share the experiences and lessons that have emerged from the journey of medical education in the Sudan, and explores the future need for continuing support and dialogue from international colleagues to maintain momentum. PMID:18158664

  5. Geochemical characterization of a Holocene aeolian profile in the Zhongba area (southern Tibet, China) and its paleoclimatic implications

    NASA Astrophysics Data System (ADS)

    Li, Tuoyu; Wu, Yongqiu; Du, Shisong; Huang, Wenmin; Hao, Chengzhi; Guo, Chao; Zhang, Mei; Fu, Tianyang

    2016-03-01

    The Zhongba area lies in the valley of the Maquan River in southern Tibet, where there are both strong modern aeolian activities and ancient aeolian sand sediments. A Holocene aeolian sand and paleosol profile in the Zhongba area was selected for study and termed (Zhuzhu (ZZ) profile). The chronology of the ZZ profile was established by optically stimulated luminescence (OSL) and accelerator mass spectrometry (AMS) 14C dating. Based on the grain size and geochemical elements of the ZZ profile, the geochemical characterization was analyzed, the Holocene aeolian activity processes were reconstructed in the study area, and the paleoclimatic implications were discussed. The major elements and the chemical indicators are highly correlated with different grain-sizes in the ZZ profile. The evolutionary sequence of the aeolian activities and the paleoclimate in Holocene reveal four stages: before 7.3 ka BP, the climate was warm and wet with weak winds when the sand paleosol developed; at 7.3-3.8 ka BP, the climate turned dry, with strong aeolian activities; at 3.8-0.7 ka BP, the climate became wetter and the winds weakened when the silt paleosol developed; and since 0.7 ka BP, it was cold and dry with strong aeolian activities.

  6. Genetic variation in insecticide tolerance in a population of southern leopard frogs (Rana sphenocephala): Implications for amphibian conservation

    USGS Publications Warehouse

    Bridges, C.M.; Semlitsch, R.D.

    2001-01-01

    Currently, conservation efforts are devoted to determining the extent and the causes of the decline of many amphibian species worldwide. Human impacts frequently degrade amphibian habitat and have been implicated in many declines. Because genetic variance is critical in determining the persistence of a species in a changing environment, we examined the amount of genetic variability present in a single population for tolerance to an environmental stressor. We examined the amount of genetic variability among full- and half-sib families in a single population of southern leopard frogs (Rana sphenocephala) with respect to their tolerance to lethal concentrations of the agricultural chemical, carbaryl. Analysis of time-to-death data indicated significant differences among full-sib families and suggests a large amount of variability present in the responses to this environmental stressor. Significant differences in responses among half-sib families indicated that there is additive genetic variance. These data suggest that this population may have the ability to adapt to environmental stressors. It is possible that declines of amphibian populations in the western United States may be attributed to low genetic variability resulting from limited migration among populations and small population sizes.

  7. Structural Inversion of the Palos Verdes Fault, Southern California, and its Implications for Seismic Hazards Assessment

    NASA Astrophysics Data System (ADS)

    Brankman, C. M.; Shaw, J. H.

    2004-12-01

    The Palos Verdes Fault (PVF) defines the western margin of the Los Angeles basin, and is regarded as a likely source of moderate to large earthquakes that would affect the coastal metropolitan regions of southern California. In most hazard compilations, the PVF is generally considered to be a vertical, predominantly right-lateral, strike-slip fault system that extends continuously from the Santa Monica thrust southward across Santa Monica Bay, crossing the Palos Verdes Peninsula and continuing southeast across the Inner Borderlands to the area of Coronado Banks. A restraining bend where the fault dips steeply to the southwest generates uplift and folding of the Palos Verdes Peninsula. However, previous studies documenting the activity, slip rate, and slip sense of the PVF have used shallow subsurface excavations and high-frequency seismic data, which have generally limited observations to the upper kilometer of the crust. We use an extensive grid of petroleum industry seismic reflection data and well logs to define the three-dimensional subsurface geometry of the PVF in the region south of the Palos Verdes Peninsula. Our seismic data cover the complete offshore extent of the fault, from Santa Monica Bay to the Coronado Banks, and provide direct constraints on the fault geometry extending down to about 5km depth. We use the shapes of folded strata imaged in the seismic data and penetrated by wells to invert for permissible geometries of the fault as it extends to the base of the seismogenic crust. Our data and structural analyses indicate that the PVF developed by Pliocene inversion of a Miocene normal fault system. The fault has a significant component of reverse slip and southwesterly dip at depth along its extent. Oblique displacement on the fault appears to be partitioned at shallow levels into nearly pure right-lateral strike slip on near-vertical faults and contractional folding above gently to moderately dipping blind-thrust fault splays. These observations are used to define a realistic 3D geometry of the PVF, to define the sizes, shapes and spatial relationships of fault segments that may rupture in earthquakes, and to extend shallow slip and slip rate estimates from previous studies to depth along the fault. This fault model will provide improved forecasts of the possible size and frequency of large earthquakes on the PVF, and will provide more accurate geometric fault representations that can be used to predict strong ground motions resulting from these events.

  8. Southern hemisphere sand furrows: spatial patterning and implications for the cryo-venting process.

    NASA Astrophysics Data System (ADS)

    Nash, Ciaran; Bourke, Mary

    2015-04-01

    Carbon dioxide is an important volatile on Mars. Seasonally, atmospheric CO2 condenses as ice on to the Martian surface and sublimates during the spring. Links have been made between a suite of observed surface features and the sublimation of surface CO2 ice; these include spider-like araneiform, gullies, and fans. Sand furrows are one such feature; suggested to form due to the erosive action of pressurised CO2 gas as it escapes through cracks in surficial ice (i.e. cryo-venting, Bourke, 2013). There are significant and important differences between the North and South Hemispheres, particularly in the seasonal CO2 deposits. Previous investigations into the formation and distribution of sand furrows on Mars have concentrated solely on the northern hemisphere. We present a study of furrows in the southern hemisphere which has yielded new data on their distribution and spatial patterning as well as providing insights into the cryo-venting process. A total of 221 dune sites were surveyed over the three Martian years' of available HiRISE data to establish the overall distribution of sand furrows. A more detailed study was carried out at eight sites using data from Mars Year 30. These sites represent a latitudinal sample of dunefields located between 40°S to 72°S. Surficial CO2 ice thickness was estimated using the Mars Climate Database (Millour et al., 2014). Our data show that sand furrows are significantly less numerous in the study region than in the northern hemisphere where data show they occur in 95% of surveyed sites. We found a strong correlation between latitude and furrow distribution. As one progresses polewards from 40°S, furrows become more numerous until 68°S. Furrows were not detected south of 72°S. Carbon dioxide ice thickness has been highlighted as a potentially important factor controlling furrow distribution in the northern hemisphere (Bourke and McGaley-Towle, 2014). Results from our investigation suggest there is a feedback mechanism between CO¬2 ice thickness and furrow formation; indicating a threshold thickness above which geomorphologically effective cryo-venting may not occur. Bourke, M. C., The Formation of Sand Furrows by Cryo-Venting on Martian Dunes. 44th Lunar and Planetary Science Conference. Lunar and Planetary Institute, Houston, 2013, pp. Abstract #2919. Bourke, M. C., McGaley-Towle, Why do sand furrows distributions vary in the North Polar latitudes on Mars? , European Geosciences Union, Vienna, Vol. 16, EGU2014-13626, 2014. Millour, E., et al., The Mars Climate Database (MCD version 5.1). Eighth International Conference on Mars. Lunar and Planetary Institute, Houston, 2014, pp. Abstract #1184.

  9. A sediment budget for the southern reach in San Francisco Bay, CA: implications for habitat restoration

    USGS Publications Warehouse

    Shellenbarger, Gregory; Wright, Scott A.; Schoellhamer, David H.

    2013-01-01

    The South Bay Salt Pond Restoration Project is overseeing the restoration of about 6000 ha of former commercial salt-evaporation ponds to tidal marsh and managed wetlands in the southern reach of San Francisco Bay (SFB). As a result of regional groundwater overdrafts prior to the 1970s, parts of the project area have subsided below sea-level and will require between 29 and 45 million m3 of sediment to raise the surface of the subsided areas to elevations appropriate for tidal marsh colonization and development. Therefore, a sufficient sediment supply to the far south SFB subembayment is a critical variable for achieving restoration goals. Although both major tributaries to far south SFB have been seasonally gaged for sediment since 2004, the sediment flux at the Dumbarton Narrows, the bayward boundary of far south SFB, has not been quantified until recently. Using daily suspended-sediment flux data from the gages on Guadalupe River and Coyote Creek, combined with continuous suspended-sediment flux data at Dumbarton Narrows, we computed a sediment budget for far south SFB during Water Years 2009–2011. A Monte Carlo approach was used to quantify the uncertainty of the flux estimates. The sediment flux past Dumbarton Narrows from the north dominates the input to the subembayment. However, environmental conditions in the spring can dramatically influence the direction of springtime flux, which appears to be a dominant influence on the net annual flux. It is estimated that up to several millennia may be required for natural tributary sediments to fill the accommodation space of the subsided former salt ponds, whereas supply from the rest of the bay could fill the space in several centuries. Uncertainty in the measurement of sediment flux is large, in part because small suspended-sediment concentration differences between flood and ebb tides can lead to large differences in total mass exchange. Using Monte Carlo simulations to estimate the random error associated with this uncertainty provides a more statistically rigorous method of quantifying this uncertainty than the more typical “sum of errors” approach. The results of this study reinforce the need for measurement of estuarine sediment fluxes over multiple years (multiple hydrologic conditions) to adequately detail the variability in flux. Additionally, the timing of breaching events for the restoration project could be tied to annual hydrologic conditions to capitalize on increased regional sediment supply.

  10. Reconstructing Younger Dryas plateau icefields in the Tweedsmuir Hills, Southern Uplands, Scotland: Style, dynamics and palaeo-climatic implications

    NASA Astrophysics Data System (ADS)

    Pearce, Danni; Rea, Brice; Bradwell, Tom; Barr, Iestyn; Small, David; McDougall, Des

    2014-05-01

    In Britain, the glacial geomorphological record has been widely utilised to infer palaeo-glacier geometries and ice dynamics, with much of this work focusing on the Scottish Highlands during the Last Glacial Interglacial Transition (LGIT), in particular the Younger Dryas (YD; c. 12.9 - 11.7 ka BP). The Southern Uplands represents the largest upland area south of the Highlands but has received limited research attention over the last century. The Tweedsmuir Hills are located in the central Southern Uplands, which form an area of dissected plateau approximately 320 km2. Early research in the 1800s identified moraines thought to be associated with the YD. However, the majority of previous work has focussed on isolated valleys and ignored the potential for plateau icefield glaciation, which has significant implications for the understanding of ice dynamics and geometries. Recent numerical modelling experiments covering the period 38 - 10.4 ka BP (Hubbard et al., 2008 cf. E109B8 and E102b2) have predicted a significant body of ice for the Southern Uplands at the onset of and throughout the YD, which cannot be verified at present due to a lack of empirical data. This research aims to provide the first systematic geomorphological mapping and Lateglacial climate reconstruction for the Tweedsmuir Hills. The results of air-photo interpretation and field mapping, which utilised a morphostratigraphic approach, have demonstrated a more extensive glaciation than previously mapped, reflecting more closely the Hubbard et al. (2009) modelled extent than earlier research. This consists of two separate icefields over the southern and northern Tweedsmuir Hills covering an area c. 45 km2 and 25 km2 respectively with Equilibrium Line Altitudes (ELAs) calculated to have ranged from c.419 m to 634 m. For both icefields ELAs of individual outlets reflect topographic controls rather than steep precipitation gradients similar to those derived for other icefields in Scotland (e.g., the Monadhliath Mountains and Beinn Dearg). New radiocarbon dating of basal contact organics place the ice-mass within the context of the YD but new Cosmogenic Nuclide Analysis (CNA) of bedrock and in situ boulders are inconclusive, implying limited erosion and limited resetting during the YD. Landform evidence also indicates smaller independent glaciers occupied some of the south-easterly catchments until the end of the YD. All of these results differ significantly from the traditional paradigm which suggests that due to low accumulation rates, only restricted ice masses developed in the Tweedsmuir Hills during this time. References: Hubbard, A. et al., (2009). Dynamic cycles, ice streams and their impact on the extent, chronology and deglaciation of the British-Irish ice sheet. Quaternary Science Reviews, (28), 7-8, 758-776

  11. An Extreme Precipitation Event in Southern Morocco in Spring 2002 and some Hydrological Implications

    NASA Astrophysics Data System (ADS)

    Knippertz, P.; Fink, A. H.

    2003-04-01

    This paper describes an extreme rain event in the semiarid to arid region south of the High Atlas in northwest Africa on 31 March and 01 April 2002. Apart from European Centre for Medium-Range Weather Forecasts analyses, satellite, radiosonde and synoptic weather station data, half-hourly observations from 12 climate stations that have been recently installed in the Dra valley in southern Morocco as part of the IMPETUS project ("An Integrated Approach to the Efficient Management of Scarce Water Resources in West Africa") are considered. Precipitation totals (of up to 77 mm in 23 hours) range in the order of magnitude of more than half of an average annual sum and constitute the heaviest storm of the last 25 years in this region. The immediate run-off caused flooding and damage to buildings. Besides, a substantial filling of water reservoirs (+23.6% of the total capacity of the great storage lake Mansour Eddahbi) and a storage of water in the High Atlas snow cover (up to 1 m) and in the soil was observed, which positively impacted on the region's water supply until the summer. The precipitation event was connected to a "tropical plume" (TP) that formed on the eastern side of an quasi-stationary upper-level subtropical trough to the west of northwestern Africa during the previous days. The large positive potential vorticity (PV) anomaly associated with this trough suggests an intrusion of dry stratospheric air connected to an anticyclonic Rossby wave breaking event. This PV anomaly interacted with the low-level temperature front connected to the TP, initiating the development of a Mediterranean cyclone on the poleward side of the TP over the course of the following days. On 01 April, the merging of the TP with the cold air cloud feature resulted in the formation of a lambda-shaped cloud system, sometimes referred to as an "instant occlusion". A trajectory and integrated water vapour flux analysis reveals that on the equatorward side of the TP, mid-level moisture transports from tropical West Africa occurred, while the high clouds connected to the actual TP originated close to tropical South America. The strong dynamically induced upper-level divergence at the inflection point of the trough and the associated synoptic-scale uplift appear to be crucial factors for the formation of the extraordinarily heavy rainfalls. Orographic forcing might have played an additional role. In contrast to cases of tropical-extratropical interactions causing precipitation in the Atlas region in late summer/early autumn, large-scale dynamical and frontogenetic effects seem to dominate over local factors as for example the triggering of convection in the moist tropical air through the daytime heating of elevated terrain. The results are contrasted to a simultaneous extreme event on the nearby Canary Island of Tenerife (up to 240 mm in three hours), which is identified as a localised thunderstorm in the unstable air underneath the axis of the upper-level cold trough that initiated the TP, potentially enhanced locally by the steep orography of the island.

  12. Islands of Education: Schooling, Civil War and the Southern Sudanese (1983-2004)

    ERIC Educational Resources Information Center

    Sommers, Marc

    2005-01-01

    Victims of warfare, famine, slavery, and isolation, the Southern Sudanese are one of the most undereducated populations in the world. Since the inception of formal education in southern Sudan a century ago, schooling has largely consisted of island-like entities surrounded by oceans of educational emptiness. Islands of Education is the first book…

  13. A seroepidemiological survey of Crimean Congo hemorrhagic fever among Cattle in North Kordufan State, Sudan

    PubMed Central

    2013-01-01

    Background Crimean Congo hemorrhagic fever (CCHF), caused by CCHF virus (CCFV), may cause a fatal hemorrhagic illness in humans with mortality rate of approximately 30%. However, in animals the disease is typically asymptomatic and no clinical hemorrhagic infections appears to be associated with CCHFV. Recently, CCHF activity has been detected in western and southern Kordufan region, Sudan. Currently, no information is available in regard to previous exposure of livestock to CCHFV infection in the region. Aims In the present study, a seroepidemiological survey was conducted to determine the prevalence of CCHF and to identify the potential risk factors associated with the disease among cattle in North Kordufan State, Sudan. Methods In this survey, 299 blood samples were collected randomly from six localities in North Kordufan State and were tested by enzyme-linked immunosorbent assay (ELISA) for detection of CCHFV-specific immunoglobulin G (IgG) antibodies. Results The result of the study indicated that the prevalence rate of CCHF was relatively high among cattle, where serological evidence of the infection was observed in 21 (7.0%) of 299 animals. Older cattle were eight times more likely to be infected with the virus (OR=8.0824, CI=1.174-66.317, p-value=0.034). Cross breeds were at 37 time higher at risk compared to endogenous breed (OR=37.06, CI=1.455-944, p-value=0.029). Highly tick-infested cattle are 6 times higher at risk for CCHF when compared to tick-free animals (OR=6.532, CI=1.042-10.852, p-value=0.030). Conclusion It is recommended that surveillance of CCHF should be extended to include other ruminant animals and to study the distribution of ticks in the region to better predict and respond to CCHF outbreak in the State of North Kordufan, Sudan. PMID:23738961

  14. Iodized Salt Consumption in Sudan: Present Status and Future Directions

    PubMed Central

    Gaffar, Abdelrahim Mutwakel; Bani, Ibrahim Ahmed

    2012-01-01

    Iodine Deficiency Disorders (IDD) Control Programme in Sudan adopted salt iodization as the long-term strategy in 1994. In 2000, it was found that less than 1% of households were using adequately-iodized salt. The objectives of this study were to: (i) study the coverage and variation of different geographical regions of Sudan regarding access to and use of iodized salt, (ii) explore the possible factors which influence the use of iodized salt, (iii) develop recommendations to help in the implementation of the Universal Salt Iodization (USI) strategy in Sudan. This paper is based on the Sudan Household Health Survey (SHHS) dataset. A total sample of 24,507 households was surveyed, and 18,786 cooking salt samples were tested for iodine levels with rapid salt-testing kits. Nationally, the percentage of households using adequately-iodized salt increased from less than 1% in 2000 to 14.4%, with wide variations between states. Access to iodized salt ranged from 96.9% in Central Equatoria to 0.4% in Gezira state. Population coverage with iodized salt in Sudan remains very low. The awareness and political support for USI programme is very weak. National legislation banning the sale of non-iodized salt does not exist. Utilization of the already-existing laws, like the National Standardization and Metrology Law (2008), to develop a compulsory national salt specification, will accelerate the USI in Sudan. PMID:23304909

  15. Exploitation and recovery of a sea urchin predator has implications for the resilience of southern California kelp forests

    PubMed Central

    Hamilton, Scott L.; Caselle, Jennifer E.

    2015-01-01

    Size-structured predator–prey interactions can be altered by the history of exploitation, if that exploitation is itself size-selective. For example, selective harvesting of larger sized predators can release prey populations in cases where only large individuals are capable of consuming a particular prey species. In this study, we examined how the history of exploitation and recovery (inside marine reserves and due to fisheries management) of California sheephead (Semicossyphus pulcher) has affected size-structured interactions with sea urchin prey in southern California. We show that fishing changes size structure by reducing sizes and alters life histories of sheephead, while management measures that lessen or remove fishing impacts (e.g. marine reserves, effort restrictions) reverse these effects and result in increases in density, size and biomass. We show that predation on sea urchins is size-dependent, such that the diet of larger sheephead is composed of more and larger sized urchins than the diet of smaller fish. These results have implications for kelp forest resilience, because urchins can overgraze kelp in the absence of top-down control. From surveys in a network of marine reserves, we report negative relationships between the abundance of sheephead and urchins and the abundance of urchins and fleshy macroalgae (including giant kelp), indicating the potential for cascading indirect positive effects of top predators on the abundance of primary producers. Management measures such as increased minimum size limits and marine reserves may serve to restore historical trophic roles of key predators and thereby enhance the resilience of marine ecosystems. PMID:25500572

  16. Exploitation and recovery of a sea urchin predator has implications for the resilience of southern California kelp forests.

    PubMed

    Hamilton, Scott L; Caselle, Jennifer E

    2015-01-22

    Size-structured predator-prey interactions can be altered by the history of exploitation, if that exploitation is itself size-selective. For example, selective harvesting of larger sized predators can release prey populations in cases where only large individuals are capable of consuming a particular prey species. In this study, we examined how the history of exploitation and recovery (inside marine reserves and due to fisheries management) of California sheephead (Semicossyphus pulcher) has affected size-structured interactions with sea urchin prey in southern California. We show that fishing changes size structure by reducing sizes and alters life histories of sheephead, while management measures that lessen or remove fishing impacts (e.g. marine reserves, effort restrictions) reverse these effects and result in increases in density, size and biomass. We show that predation on sea urchins is size-dependent, such that the diet of larger sheephead is composed of more and larger sized urchins than the diet of smaller fish. These results have implications for kelp forest resilience, because urchins can overgraze kelp in the absence of top-down control. From surveys in a network of marine reserves, we report negative relationships between the abundance of sheephead and urchins and the abundance of urchins and fleshy macroalgae (including giant kelp), indicating the potential for cascading indirect positive effects of top predators on the abundance of primary producers. Management measures such as increased minimum size limits and marine reserves may serve to restore historical trophic roles of key predators and thereby enhance the resilience of marine ecosystems. PMID:25500572

  17. Late Quaternary environments in the White Nile region, Sudan

    NASA Astrophysics Data System (ADS)

    Williams, Martin A. J.; Adamson, Donald; Cock, Bryan; McEvedy, Rosanna

    2000-11-01

    Both the channel of the lower White Nile and the soils adjacent to the river have a number of special characteristics, which are a direct reflection of its unique late Quaternary history. These attributes include a straight channel pattern (despite a flood gradient of 1 in 100 000 and a very fine suspension load) and localised concentrations of buried evaporites, carbonates, and highly saline subsoils at intervals alongside the river. Late Quaternary aeolian, fluviatile and lacustrine deposits in and near the lower White Nile valley reveal a strong contrast between the often dry, cold and windy late Pleistocene climates characteristic of the Last Glacial Maximum (18 000±3000 BP) and the wetter and warmer climates prevalent in those regions towards 11 500-11 000 BP, 9500 BP and 8500-7000 BP. Buried shell-beds and recessional strandlines indicate a sudden and rapid regression of the vastly expanded terminal Pleistocene White Nile in possible Younger Dryas times (11 000-10 000 BP) coinciding with probable temporary closure of Lake Victoria in the Ugandan upper reaches of the White Nile. The stable carbon and oxygen isotopic composition of freshwater gastropod shells in the lower White Nile region is consistent with a stronger summer monsoon towards 11 500-11 000 BP and again towards 8500-7000 BP. At intervals between ca. 18 000 and 12 000 BP, the lower White Nile was a strongly seasonal river, which shifted course frequently and carried large quantities of medium and coarse sand. The present Sudd swamps in the southern Sudan cannot have been in existence during those times, but came into existence (or became reestablished) during the Holocene.

  18. Development of sedimentary cycles on the east Sahara craton since Silurian time (northwest Sudan/southwest Egypt)

    SciTech Connect

    Wycisk, P. )

    1988-08-01

    The sedimentary succession of southwest Egypt and northwest Sudan, formerly called the Nubia(n) Sandstone, has been subdivided into a number of formations. The predominantly fluvial sediments which characterize Silurian to Upper Cretaceous strata of this region were repeatedly interrupted by marine transgressions that rapidly progressed toward the south since Ordovician time. Thin, shallow marine sequences of different ages can be traced for more than 1,000 km within the studied area. The development of the sedimentary cycles will be pointed out by surface and subsurface data along a cross section from the southern Dakhla basin in the north to the Misaha trough and Abyad basin in the south.

  19. Determining the effect of climate change and development on water resources management in the Sudan

    NASA Astrophysics Data System (ADS)

    Satti, S.; Zaitchik, B.; Siddiqui, S.

    2013-12-01

    The effects of development and the uncertainty of climate change in East Africa provide a myriad of challenges for water managers along the Blue Nile. The construction of the Grand renaissance dam (GRD), as well as the unknown trajectory of precipitation trends in the Ethiopian highlands may greatly affect the countries that rely on the Nile. Sudan's huge irrigation potential and dams that feed multiple current irrigation schemes as well as its location within the basin means that Sudan's water management decisions may reverberate and have social, economic and political implications within the east African sub-region. Here, we apply a suite of state-of-the-art hydrology and climate analysis tools to evaluate the sensitivity of Sudan's optimal hydropower and irrigation development pathways to hydrologic variability and climate change. Present day hydrologic conditions are derived from a gridded implementation of the Noah Land Surface Model (LSM) that includes representation of typical irrigation practices in the region. Noah is implemented using the NASA Land Information System (LIS), and draws forcing data from a combination of reanalysis and satellite meteorological products. Additional satellite inputs are used to provide a constraint on Noah evapotranspiration estimates and to acquire parameters such as crop water requirements that are crucial in determining yield and agricultural production. Future climate conditions are projected using statistical downscaling techniques trained to historical meteorological records and projected forward using inputs from the 5th Coupled Model Intercomparison Project (CMIP5) simulation database. These climatic and hydrologic inputs are combined with agronomic and economic inputs to drive an optimization model developed within the General Algebraic Modeling System (GAMS). By using output and results from climate, hydrologic and optimization models this research aims to show how these models can be integrated to aid decision makers in the quest to better manage their water resources.

  20. VOLATILE ORGANIC COMPOUNDS FROM VEGETATION IN SOUTHERN YUNNAN PROVINCE, CHINA: EMISSION RATES AND SOME POTENTIAL REGIONAL IMPLICATIONS

    EPA Science Inventory

    Little information is currently available regarding emissions of biogenic volatile organic compounds (BVOCs) in southern Asia. To address the need for BVOC emission estimates in regional atmospheric chemistry simulations, 95 common plant species were screened for emissions of BVO...

  1. Linkages between Southern Ocean Cloud-Radiative Processes and the Large-Scale Southern Hemisphere Circulation, and Their Implications for Climate Model Projections

    NASA Astrophysics Data System (ADS)

    Grise, K. M.; Polvani, L. M.

    2014-12-01

    Southern Ocean cloud cover is strongly linked to extratropical weather systems, and thus to the position of the Southern Hemisphere (SH) storm track and the mid-latitude eddy-driven jet stream. Consequently, if the jet moves poleward (either as a result of natural variability or anthropogenic forcing), a notable change in cloud-radiative processes might be expected. In this study, we examine the cloud-radiative anomalies associated with interannual variability in the latitude of the SH mid-latitude eddy-driven jet, using two satellite data sets (ISCCP-FD and CERES) and 20 global climate models from Phase 5 of the Coupled Model Intercomparison Project (CMIP5). Two distinct model types are found. In the first class of models ("type I models"), the total cloud fraction is reduced at SH mid-latitudes as the jet moves poleward, contributing to enhanced shortwave radiative warming. In the second class of models ("type II models"), this dynamically-induced cloud-radiative warming effect is largely absent. Type I and type II models have distinct deficiencies in their representation of observed Southern Ocean clouds, but comparison with the two satellite data sets indicates that the cloud-dynamics behavior of type II models is more realistic. Because the SH mid-latitude jet shifts poleward in response to CO2 forcing, the cloud-dynamics biases uncovered from interannual variability are directly relevant for climate change projections. In CMIP5 model experiments with abruptly quadrupled atmospheric CO2 concentrations, the global-mean surface temperature initially warms more in type I models, even though their equilibrium climate sensitivity is not significantly larger. In type I models, this larger initial warming is linked to the rapid adjustment of the circulation and clouds to CO2 forcing in the SH, where a nearly instantaneous poleward shift of the mid-latitude jet is accompanied by a reduction in the reflection of solar radiation by clouds. In type II models, the SH jet also shifts rapidly poleward with CO2 quadrupling, but it is not accompanied by cloud-radiative warming anomalies, resulting in a smaller initial global-mean surface temperature warming.

  2. Present status of tick-borne diseases in Sudan.

    PubMed

    El Hussein, A R M; Majid, A M Abdel; Shawgi, M H

    2004-01-01

    Ticks and tick-borne diseases are widespread in the Sudan, cause substantial economic losses and constitute major obstacles to the development of animal wealth. Most important among these diseases are tropical theileriosis, malignant ovine theileriosis, cowdriosis, babesiosis, anaplasmosis and avian spirochaetosis. However, knowledge about ticks and tick-borne diseases is still fragmentary and far from complete. The large number of tick species, the multplicity of transmitted agents and the diverse ecoclimatic zones of the Sudan provide a unique opportunity to host diverse research activities that could benefit other regions in Africa. PMID:16929763

  3. Impact of the 2011 Southern US Drought on Ground-Level Particulate Matters (PM) in Summertime and Implication for Drought-Driven PM Response in Future Climate

    NASA Astrophysics Data System (ADS)

    Xie, Y.; Wang, Y.; Dong, W.; Zhang, Q.; Chai, L.; Zhang, L.

    2014-12-01

    Drought has wide spread influence over the continental US. Climate predictions suggest increasing frequencies and intensity in droughts, particularly over the southern and western US. In this study, we first present a quantitative assessment of the impacts of the 2011 Southern US drought on the distribution and budget of surface PM2.5 in the summertime using observations and the GEOS-Chem model. Through quantifying the complex dependence of PM2.5 species to meteorology parameters, we find different responses of OC and sulfate to drought conditions. There is an average enhancement of 26% (p < 10-4) in total PM2.5 over the southern US region during the drought, which is largely attributed to OC enhancements driven by increased emissions from wildfires and trans-boundary inflow from Mexico. By contrast, over central and eastern Texas, surface PM2.5 shows a mean decrease of 11% driven by a 26% (p < 0.03) reduction in sulfate due to decreased aqueous-phase oxidation. On the basis of our PM2.5 budget analysis of this drought event, a statistical approach is developed to estimate the impacts of similar droughts on PM2.5 air quality in the past decades and validated. Finally, we will apply the statistical relationship to discuss the implications on PM air quality of future changes in drought projected by climate models.

  4. Reworked planktonic Foraminifera from the Late Rupelian of the southern Upper Rhine Graben and their palaeogeographic and biostratigraphic implications

    NASA Astrophysics Data System (ADS)

    Pirkenseer, C.; Spezzaferri, S.; Berger, J.-P.

    2009-04-01

    During the Late Rupelian the widespread second transgression (corresponding to international Ru2-3 transgressions; BERGER et al. 2005) affected the whole Upper Rhine Graben basin and led to the deposition of the several hundred meters thick marine "Série grise". An abrupt transition (erosion surface) between the uppermost "Série grise" and Niederroedern Formation indicates the change to fluviatile and lacustrine conditions throughout the basin close to the Late Rupelian / Early Chattian boundary. Abundant reworked Middle to Late Cretaceous (e.g., Marginotruncana pseudolinneiana) and Late Paleocene to Late Eocene (e.g., Acarinina bullbrooki, Morozovella subbotinae, Turborotalia cocoaensis) ranging planktonic Foraminifera occur in the "Série Grise" and equivalent lithological units of the Upper Rhine Graben and the Mainz Basin (e.g., FISCHER 1965, PIRKENSEER 2007, SCHÄFER & KUHN 2004). At least Late Cretaceous, Ypresian, Lutetian and Priabonian ages of source sediments are indicated by the overlapping biostratigraphic ranges of the reworked specimens. Abundant reworked material first appears in the lower "Couches à Mélettes" and reaches its acme in the increasingly "Marnes à Cyrènes" (terminal "Série grise"). Only sparse records are documented from the subsequent terrestrial Niederroedern Formation. These reworking events are linked to intervals of increased clastic input throughout the "Série grise". The planktonic Foraminifera are proposed to be reworked from related alpine deposits (later Helvetikum?) via a northwards trending fluviatile system, as no autochthonous Cretaceous and Early to Middle Eocene marine sediments were deposited within the graben basin. Furthermore other possible source areas (e.g., Paris Basin) were either not connected to the Upper Rhine Graben or were not subject to erosion in the Late Rupelian. This accords with the proposition (ROUSSÉ 2006) of a vast northwards prograding delta-system that was located close to the southern margin of the Upper Rhine Graben. Reworked Mesozoic and Paleogene calcareous nannoplankton from the Upper Rhine Graben and the Mainz Basin confirms the data derived from planktonic Foraminifera. The existence of reworked planktonic Foraminifera influences the biostratigraphic interpretation of the assemblage ranges attributed to "Série grise" samples. Facultatively reworked planktonic Foraminifera as Subbotina utilisindex and Pseudohastigerina micra ranging from the Lutetian to the Late Rupelian should not be included in the biostratigraphic analyses, as the occurrences of these facultatively reworked species are always linked to those of exclusively Cretaceous and Eocene age. Therefore the age of the "Série grise" deposits at Allschwil-2 is most likely to be placed within the "Chiloguembelina cubensis - Globigerinella obesa / Globorotaloides variabilis"-assemblage range of Mid P20 to Final P21a, lasting considerably longer than the very short Mid P20 range based on the presence of Pseudohastigerina micra as "last occurrence"-marker (PIRKENSEER 2007). This study was funded by the Swiss National Science Foundation projects 109457 and 118025. References: BERGER, J.-P., REICHENBACHER, B., BECKER, D., et al. (2005): Eocene-Pliocene time scale and stratigraphy of the Upper Rhine Graben (URG) and the Swiss Molasse Basin (SMB). - International Journal of Earth Sciences, 94, 4: 711-731. FISCHER, H. (1965): Geologie des Gebietes zwischen Blauen und Pfirter Jura. - Beiträge zur geologischen Karte der Schweiz, NF 122: 106p. PIRKENSEER, C. (2007): Foraminifera, Ostracoda and other microfossils of the Southern Upper Rhine Graben - Palaeoecology, biostratigraphy, palaeogeography and geodynamic implications. - PhD thesis: 340p, Fribourg. ROUSSÉ, S. (2006): Architecture et dynamique des séries marines et continentales de ĺOligocène Moyen et Supérieur du Sud du Fossé Rhénan: Evolution des milieux de dépôt en contexte de rift en marge de ĺavant-pays alpin. - PhD: 471p, Strasbourg. SCHÄFER, P. & KUHN, W. (2004): Mikropaläontologische und lithologische Abgrenzungskriterien zwischen Oberem Rupelton [= Rosenberg-Subformation] und "Schleichsand" [= Stadecken-Formation] im Rupelium (Tertiär) des Mainzer Beckens. - Mainzer geowissenschaftliche Mitteilungen, 32: 139-178.

  5. The influence of extreme winds on coastal oceanography and its implications for coral population connectivity in the southern Arabian Gulf.

    PubMed

    Cavalcante, Geórgenes H; Feary, David A; Burt, John A

    2016-04-30

    Using long-term oceanographic surveys and a 3-D hydrodynamic model we show that localized peak winds (known as shamals) cause fluctuation in water current speed and direction, and substantial oscillations in sea-bottom salinity and temperature in the southern Persian/Arabian Gulf. Results also demonstrate that short-term shamal winds have substantial impacts on oceanographic processes along the southern Persian/Arabian Gulf coastline, resulting in formation of large-scale (52km diameter) eddies extending from the coast of the United Arab Emirates (UAE) to areas near the off-shore islands of Iran. Such eddies likely play an important role in transporting larvae from well-developed reefs of the off-shore islands to the degraded reef systems of the southern Persian/Arabian Gulf, potentially maintaining genetic and ecological connectivity of these geographically distant populations and enabling enhanced recovery of degraded coral communities in the UAE. PMID:26506023

  6. Southern Peru desert shattered by the great 2001 earthquake: Implications for paleoseismic and paleo-El Nino-Southern Oscillation records

    USGS Publications Warehouse

    Keefer, David K.; Moseley, Michael E.

    2004-01-01

    In the desert region around the coastal city of Ilo, the great southern Peru earthquake of June 23, 2001 (8.2-8.4 moment magnitude), produced intense and widespread ground-failure effects. These effects included abundant landslides, pervasive ground cracking, microfracturing of surficial hillslope materials, collapse of drainage banks over long stretches, widening of hillside rills, and lengthening of first-order tributary channels. We have coined the term "shattered landscape" to describe the severity of these effects. Long-term consequences of this landscape shattering are inferred to include increased runoff and sediment transport during postearthquake rainstorms. This inference was confirmed during the first minor postearthquake rainstorm there, which occurred in June and July of 2002. Greater amounts of rainfall in this desert region have historically been associated with El Nin??o events. Previous studies of an unusual paleoflood deposit in this region have concluded that it is the product of El Nin??o-generated precipitation falling on seismically disturbed landscapes. The effects of the 2001 earthquake and 2002 rainstorm support that conclusion.

  7. Southern Peru desert shattered by the great 2001 earthquake: Implications for paleoseismic and paleo-El Niño–Southern Oscillation records

    PubMed Central

    Keefer, David K.; Moseley, Michael E.

    2004-01-01

    In the desert region around the coastal city of Ilo, the great southern Peru earthquake of June 23, 2001 (8.2–8.4 moment magnitude), produced intense and widespread ground-failure effects. These effects included abundant landslides, pervasive ground cracking, microfracturing of surficial hillslope materials, collapse of drainage banks over long stretches, widening of hillside rills, and lengthening of first-order tributary channels. We have coined the term “shattered landscape” to describe the severity of these effects. Long-term consequences of this landscape shattering are inferred to include increased runoff and sediment transport during postearthquake rainstorms. This inference was confirmed during the first minor postearthquake rainstorm there, which occurred in June and July of 2002. Greater amounts of rainfall in this desert region have historically been associated with El Niño events. Previous studies of an unusual paleoflood deposit in this region have concluded that it is the product of El Niño-generated precipitation falling on seismically disturbed landscapes. The effects of the 2001 earthquake and 2002 rainstorm support that conclusion. PMID:15263069

  8. Mycetoma in the Sudan: An Update from the Mycetoma Research Centre, University of Khartoum, Sudan

    PubMed Central

    Fahal, Ahmed; Mahgoub, EL Sheikh; Hassan, Ahmed M. EL; Abdel-Rahman, Manar Elsheikh

    2015-01-01

    This communication reports on the Mycetoma Research Centre of the University of Khartoum, Sudan experience on 6,792 patients seen during the period 1991–2014.The patients were predominately young (64% under 30 years old) males (76%). The majority (68%) were from the Sudan mycetoma belt and 28% were students. Madurella mycetomatis eumycetoma was the most common type (70%). In 66% of the patients the duration of the disease was less than five years, and 81% gave a history of sinuses discharging mostly black grains (78%). History of trauma at the mycetoma site was reported in 20%. Local pain was reported in 27% of the patients, and only 12% had a family history of mycetoma. The study showed that 57% of the patients had previous surgical excisions and recurrence, and only 4% received previous medical treatment for mycetoma. Other concomitant medical diseases were reported in 4% of the patients. The foot (76%) and hand (8%) were the most commonly affected sites. Less frequently affected sites were the leg and knee (7%), thigh (2%), buttock (2%) and arm and forearm (1%). Rare sites included the chest wall, head and neck, back, abdominal wall, perineum, oral cavity, tongue and eye. Multiple sites mycetoma was recorded in 135 (2%) of cases. At presentation, 37% of patients had massive lesions, 79% had sinuses, 8% had local hyper-hydrosis at the mycetoma lesion, 11% had regional lymphadenopathy, while 6% had dilated tortuous veins proximal to the mycetoma lesions. The diagnosis of mycetoma was established by combined imaging techniques and cytological, histopathological, serological tests and grain culture. Patients with actinomycetoma received a combination of antimicrobial agents, while eumycetoma patients received antifungal agents combined with various surgical excisions. Surgical excisions in the form of wide local excision, debridement or amputation were done in 807 patients, and of them 248 patients (30.7%) had postoperative recurrence. Different types of amputations were done in 120 patients (1.7%). PMID:25816316

  9. New chronology for the southern Kalahari Group sediments with implications for sediment-cycle dynamics and early hominin occupation

    NASA Astrophysics Data System (ADS)

    Matmon, Ari; Hidy, Alan J.; Vainer, Shlomy; Crouvi, Onn; Fink, David; Erel, Yigal; Arnold, M.; Aumaître, G.; Bourlès, D.; Keddadouche, K.; Horwitz, Liora K.; Chazan, Michael

    2015-07-01

    Kalahari Group sediments accumulated in the Kalahari basin, which started forming during the breakup of Gondwana in the early Cretaceous. These sediments cover an extensive part of southern Africa and form a low-relief landscape. Current models assume that the Kalahari Group accumulated throughout the entire Cenozoic. However, chronology has been restricted to early-middle Cenozoic biostratigraphic correlations and to OSL dating of only the past ~ 300 ka. We present a new chronological framework that reveals a dynamic nature of sedimentation in the southern Kalahari. Cosmogenic burial ages obtained from a 55 m section of Kalahari Group sediments from the Mamatwan Mine, southern Kalahari, indicate that the majority of deposition at this location occurred rapidly at 1-1.2 Ma. This Pleistocene sequence overlies the Archaean basement, forming a significant hiatus that permits the possibility of many Phanerozoic cycles of deposition and erosion no longer preserved in the sedimentary record. Our data also establish the existence of a shallow early-middle Pleistocene water body that persisted for > 450 ka prior to this rapid period of deposition. Evidence from neighboring archeological excavations in southern Africa suggests an association of high-density hominin occupation with this water body.

  10. Assessing Vegetation Cover Dynamics Induced by Policy-Driven Ecological Restoration and Implication to Soil Erosion in Southern China.

    PubMed

    Zhang, Jien; Wang, Tianming; Ge, Jianping

    2015-01-01

    In the aftermath of the severe droughts and floods at the end of the 20th century, the Chinese government launched several ecological restoration projects, including the Natural Forest Protection Program in 1998 and the Grain-for-Green Program in 1999, to promote afforestation and reforestation to reduce surface runoff and consequent soil erosion nationwide. However, it is still unclear how vegetation has changed in southern China since the launch of these programs. In this study, we used the MODIS Enhanced Vegetation Index (EVI) to analyze the vegetation cover dynamics in southern China from 2000 to 2009 and evaluate the resulting effects of controlling soil erosion. Our observations indicate that 5.3% of the study area significantly increased and 0.98% significantly decreased in EVI value (p < 0.05). The spring EVI had largest increase in space. The conversions of croplands on steep slopes to forests resulting from national policies led to significant increases in EVI. The increase in EVI was not driven by annual average temperature and annual precipitation. By referencing ecological restoration statistical data and field observations, we showed that ecological restoration programs significantly improved vegetation cover in southern China. Increase in the area of farmland-converted forestlands has reduced soil erosion based upon monitoring sediment yields at hydrologic stations in the Yangtze River. This study displays the spatial patterns of trend in vegetation growth since the beginning of the 21st century in southern China and highlights the important role of China's afforestation program. PMID:26115116

  11. Assessing Vegetation Cover Dynamics Induced by Policy-Driven Ecological Restoration and Implication to Soil Erosion in Southern China

    PubMed Central

    Zhang, Jien; Wang, Tianming; Ge, Jianping

    2015-01-01

    In the aftermath of the severe droughts and floods at the end of the 20th century, the Chinese government launched several ecological restoration projects, including the Natural Forest Protection Program in 1998 and the Grain-for-Green Program in 1999, to promote afforestation and reforestation to reduce surface runoff and consequent soil erosion nationwide. However, it is still unclear how vegetation has changed in southern China since the launch of these programs. In this study, we used the MODIS Enhanced Vegetation Index (EVI) to analyze the vegetation cover dynamics in southern China from 2000 to 2009 and evaluate the resulting effects of controlling soil erosion. Our observations indicate that 5.3% of the study area significantly increased and 0.98% significantly decreased in EVI value (p < 0.05). The spring EVI had largest increase in space. The conversions of croplands on steep slopes to forests resulting from national policies led to significant increases in EVI. The increase in EVI was not driven by annual average temperature and annual precipitation. By referencing ecological restoration statistical data and field observations, we showed that ecological restoration programs significantly improved vegetation cover in southern China. Increase in the area of farmland-converted forestlands has reduced soil erosion based upon monitoring sediment yields at hydrologic stations in the Yangtze River. This study displays the spatial patterns of trend in vegetation growth since the beginning of the 21st century in southern China and highlights the important role of China’s afforestation program. PMID:26115116

  12. Late Holocene Marsh Expansion in Southern San Francisco Bay, California: Implications for the Use of Historic Baselines as Restoration Targets

    EPA Science Inventory

    Currently, the largest tidal wetlands restoration project on the US Pacific Coast is being planned and implemented in southern San Francisco Bay; however, knowledge of baseline conditions of salt marsh extent in the region prior to European settlement is limited. Here, analysis o...

  13. Base- and precious-metal deposits in the Basin and Range of Southern California and Southern Nevada - Metallogenic implications of lead isotope studies

    USGS Publications Warehouse

    Church, S.E.; Cox, D.P.; Wooden, J.L.; Tingley, J.V.; Vaughn, R.B.

    2005-01-01

    Southern California and southern Nevada contain abundant lead-zinc deposits with strikingly different characteristics. On the west, the Darwin Terrane contains abundant Jurassic and Cretaceous intrusions surrounded by lead-zinc skarn and replacement deposits rich in pyrite and manganese minerals. The Tecopa Terrane is east of the Darwin Terrane and contains some lead deposits that are hosted by the Proterozoic Noonday Dolomite. These lead deposits have no consistent relation to igneous rocks; they contain mainly galena, and are devoid of pyrite and manganese minerals. Other skarn and vein deposits in the Ivanpah and Tecopa districts are more closely associated with igneous rocks. Mississippi Valley type lead-zinc deposits are present still farther to the east in the Goodsprings Terrane in Nevada. These deposits are hosted by breccias formed below the Mississippian-Pennsylvanian unconformity and are unrelated to igneous rocks. Deposits in the Darwin Terrane have lead isotopic signatures that lie along a mantle-sediment mixing line indicating that they formed in a continental arc setting analogous to that for the plutons in the Sierra Nevada batholith [Chen, J.H. and Tilton, G.R., 1991. Application of lead and strontium isotopic relationships to the petrogenesis of granitoid rocks, central Sierra Nevada batholith, California. Geological Society of America Bulletin 103, 439-447]. Encroachment of this continental arc on the North American continent in the eastern part of the Darwin Terrane resulted in a lead isotopic signature that is like that of the strongly contaminated plutons [Chen, J.H. and Tilton, G.R., 1991. Application of lead and strontium isotopic relationships to the petrogenesis of granitoid rocks, central Sierra Nevada batholith, California. Geological Society of America Bulletin 103, 439-447]. Many deposits from the Inyo Mountains on east side of the Owens Valley have lead isotopic signatures that reflect this encroachment. To the east in the Tecopa Terrane, encroachment of the continental arc on the Mojave crust resulted in partial melting of 1.7 Ga amphibolite and granulite facies rocks to produce the plutons and mineral deposits associated with plutons in this terrane. Lead from deposits in this terrane hosted in the Proterozoic Noonday Dolomite and associated rocks have a lead isotope signature that reflects hydrothermal circulation of fluids in the Mojave supracrustal rocks. The boundary between the Darwin Terrane and the Tecopa Terrane lies just west of the Ash Valley-Panamint Range Fault and is bounded by the Towne Fault on the north and the Garlock Fault on the south. Lead isotopic data from the Goodsprings district in southwestern Nevada, east of the Tecopa Terrane, form a 1.45 Ga linear array that is indicative of Mississippi Valley type mineralization. Although we have no independent evidence of the timing of the tectonic events that formed these deposits, it is likely that all formed as a result of the Mesozoic collision of the Panthalassen crust with the North American continent. ?? 2005 Elsevier B.V. All rights reserved.

  14. Nosocomial Outbreak of Crimean-Congo Hemorrhagic Fever, Sudan

    PubMed Central

    Aradaib, Imadeldin E.; Erickson, Bobbie R.; Mustafa, Mubarak E.; Khristova, Marina L.; Saeed, Nageeb S.; Elageb, Rehab M.

    2010-01-01

    To confirm the presence of Crimean-Congo hemorrhagic fever in Sudan, we tested serum of 8 patients with hemorrhagic fever in a rural hospital in 2008. Reverse transcription–PCR identified Crimean-Congo hemorrhagic fever virus. Its identification as group III lineage indicated links to virus strains from South Africa, Mauritania, and Nigeria. PMID:20409377

  15. New sources of grain mold resistance among accessions from Sudan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fifty-nine sorghum accessions from Sudan were evaluated in replicated plots at Isabela, Puerto Rico, for resistance against Fusarium thapsinum, one of the causal agents of grain mold. The environmental conditions during this study, especially at and after physiological maturity were optimal for gra...

  16. The Role of Education in Sudan's Civil War

    ERIC Educational Resources Information Center

    Breidlid, Anders

    2013-01-01

    This article addresses the role that education plays in conflict, with specific reference to the civil war in Sudan. It analyses the ideological basis of the Sudanese government (GoS) during the civil war, with special reference to the role of religion and ethnicity. It shows how the primary education system was based on the Islamist ideology of

  17. The Role of Education in Sudan's Civil War

    ERIC Educational Resources Information Center

    Breidlid, Anders

    2013-01-01

    This article addresses the role that education plays in conflict, with specific reference to the civil war in Sudan. It analyses the ideological basis of the Sudanese government (GoS) during the civil war, with special reference to the role of religion and ethnicity. It shows how the primary education system was based on the Islamist ideology of…

  18. Sudanese Images of the Other: Education and Conflict in Sudan

    ERIC Educational Resources Information Center

    Breidlid, Anders

    2010-01-01

    Education can contribute to peace and reconciliation as well as to conflict and strife. The complex, often contradictory role of education in conflict is explored in this article in relation to Sudan. The focus of the article is the North-South conflict, bearing in mind that other, "minor" wars and military clashes in both the North and South have…

  19. Development and in-house validation of a liquid chromatography-electrospray-tandem mass spectrometry method for the simultaneous determination of Sudan I, Sudan II, Sudan III and Sudan IV in hot chilli products.

    PubMed

    Calbiani, F; Careri, M; Elviri, L; Mangia, A; Pistarà, L; Zagnoni, I

    2004-07-01

    An accurate method based on the use of reversed-phase (RP) liquid chromatography-tandem mass spectrometry interfaced with electrospray (LC-ESI-MS/MS) was devised for the determination of Sudan I, Sudan II, Sudan III and Sudan IV in hot chilli food samples. A simple sample treatment procedure entailing the use of an extraction step with acetone without clean-up was developed. A C18 column with an aqueous formic acid/methanol mixture as the mobile phase was used under isocratic conditions. Mass spectral acquisition was done in positive ion mode by applying selected reaction monitoring of three fragmentation transitions per compound to provide a high degree of selectivity. The method was in-house validated in terms of detection limits (LOD), quantitation limits (LOQ), linearity, sensitivity, accuracy, recovery, and selectivity on two kinds of hot chilli sauces. Good results in the low ng/g level were obtained for LOD and LOQ of all analytes in matrices. Under both intra-day repeatability (R.S.D. between 1 and 13%) and intermediate precision (about 5-15% R.S.D. for both chilli sauce matrices) conditions, precision proved to be typical of determinations based on electrospray LC-MS and acceptable for routine monitoring purposes. Extraction recoveries for all four azo-dyes in chilli tomato sauce ranged from 92 to 103% at a spiking level of 5 microg/kg, whereas values between 72 and 97% were calculated in chilli tomato and cheese sauce at the same concentration level. The applicability of the method to the determination of Sudan azo-dyes in hot chilli products was demonstrated. PMID:15296396

  20. 31 CFR 538.505 - Provision of certain legal services to the Government of Sudan, persons in Sudan, or benefitting...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... administrative proceedings in defense of property interests subject to U.S. jurisdiction of the Government of.... law requires access to legal counsel at public expense. (c) Enforcement of any lien, judgment... to transfer or otherwise alter or affect a property interest of the Government of Sudan is...

  1. 31 CFR 538.505 - Provision of certain legal services to the Government of Sudan, persons in Sudan, or benefitting...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... administrative proceedings in defense of property interests subject to U.S. jurisdiction of the Government of.... law requires access to legal counsel at public expense. (c) Enforcement of any lien, judgment... to transfer or otherwise alter or affect a property interest of the Government of Sudan is...

  2. 31 CFR 538.505 - Provision of certain legal services to the Government of Sudan, persons in Sudan, or benefitting...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... administrative proceedings in defense of property interests subject to U.S. jurisdiction of the Government of.... law requires access to legal counsel at public expense. (c) Enforcement of any lien, judgment... to transfer or otherwise alter or affect a property interest of the Government of Sudan is...

  3. 31 CFR 538.505 - Provision of certain legal services to the Government of Sudan, persons in Sudan, or benefitting...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... administrative proceedings in defense of property interests subject to U.S. jurisdiction of the Government of.... law requires access to legal counsel at public expense. (c) Enforcement of any lien, judgment... to transfer or otherwise alter or affect a property interest of the Government of Sudan is...

  4. Role of Eddies in Controlling the Uptake of Anthropogenic Ocean in the Southern Ocean and Implications for Recent Claims of a Decline in the Ocean Carbon Sink

    NASA Astrophysics Data System (ADS)

    Eckerle, K.; Khatiwala, S.

    2008-12-01

    There is increasing recognition of the importance of the Southern Ocean in the global carbon cycle. Indeed, a recent reconstruction shows that over 40% of the anthropogenic CO2 in the ocean in 2007 entered south of 50 deg S. However, recent work by Le Qur et al. (Science, 2007) and Lovenduski et al (GBC, 2007) suggests that CO2 uptake by the Southern Ocean has declined over the last few decades due to an increase in the westerlies. They attribute the decrease to an increase in the strength of the Southern Ocean meridional overturning circulation (MOC) and an associated increase in the outgassing of "natural" CO2. If true, this is cause for considerable concern since most IPCC models predict a continued strengthening of the zonal winds in the Southern Ocean, implying a further weakening of the ocean CO2 sink, with important implications for future climate. Central to the above claims is the assumption that the MOC responds in this simple manner to the winds. However, there are theoretical reasons to suspect otherwise. Here, we use a combination of theory and numerical simulation to better understand and quantify the dynamical response of the Southern Ocean MOC to changes in the zonal wind. Our results show that this response is extremely sensitive to the treatment of baroclinic eddies in ocean models. Specifically, the use of a "Gent- McWilliams-type" parameterization with a constant eddy-transfer coefficient, as is conventional in the coarse resolution ocean models of the type used by the above studies, significantly overestimates the sensitivity-- and perhaps even its sign--of the overturning to changes in the strength of the westerlies. In contrast, the use of a more realistic eddy-parameterization with a spatially variable eddy-transfer coefficient renders the strength of the overturning -- and hence the anthropogenic CO2 uptake -- largely insensitive to changes in the zonal wind. These results, which are supported by idealized eddy-resolving calculations, contradict recent claims of a decline in the ocean carbon sink.

  5. Growth responses of Ulva prolifera to inorganic and organic nutrients: Implications for macroalgal blooms in the southern Yellow Sea, China.

    PubMed

    Li, Hongmei; Zhang, Yongyu; Han, Xiurong; Shi, Xiaoyong; Rivkin, Richard B; Legendre, Louis

    2016-01-01

    The marine macrophyte Ulva prolifera is the dominant green-tide-forming seaweed in the southern Yellow Sea, China. Here we assessed, in the laboratory, the growth rate and nutrient uptake responses of U. prolifera to different nutrient treatments. The growth rates were enhanced in incubations with added organic and inorganic nitrogen [i.e. nitrate (NO3(-)), ammonium (NH4(+)), urea and glycine] and phosphorus [i.e. phosphate (PO4(3-)), adenosine triphosphate (ATP) and glucose 6-phosphate (G-6-P)], relative to the control. The relative growth rates of U. prolifera were higher when enriched with dissolved organic nitrogen (urea and glycine) and phosphorus (ATP and G-6-P) than inorganic nitrogen (NO3(-) and NH4(+)) and phosphorus (PO4(3-)). In contrast, the affinity was higher for inorganic than organic nutrients. Field data in the southern Yellow Sea showed significant inverse correlations between macroalgal biomass and dissolved organic nutrients. Our laboratory and field results indicated that organic nutrients such as urea, glycine and ATP, may contribute to the development of macroalgal blooms in the southern Yellow Sea. PMID:27199215

  6. Paleomagnetism, rock magnetism and opaque mineralogy of iron ore deposits from southern Mexico and their implications for quantitative modelling of magnetometric data

    SciTech Connect

    Alva-Valdivia, L.M.; Fucugauchi, Urrutia, J.; Bohnel, H.; Moran Zenteno, D.J. )

    1990-06-01

    Paleomagnetism, Rock Magnetism and Opaque Mineralogy of Iron Ore Deposits from Southern Mexico and Their Implications for Quantitative Modelling of Magnetometric Data. The tectonic history of the Pacific continental margin is critical for understanding their mineral deposits. The margin presents intrusive and volcanic activity characteristic of magmatic arcs of subduction zones, which are genetically related with deposits of Cu, Fe, Mo, Au, and Ag. Although the tectonic history has been complex, involving oblique plate subduction, lateral movements, accretion of magmatic arcs and oceanic plateaux, and lateral displacements of major blocks, the mineral deposits are spatially distributed along elongated belts that roughly follow the margin. The authors have conducted paleomagnetic, rock magnetic, and petrological studies of the iron ore deposits to investigate genesis, magnetic mineralogy, stratigraphic relationships, metamorphism, and applications on quantitative modelling of magnetometric data. The remanent magnetization and susceptibility data are necessary for interpretation of magnetic anomalies. The results permit a comparison of the mineral deposits along the continental margin.

  7. Lessons learned from post-wildfire monitoring and implications for land management and regional drinking water treatability in Southern Rockies of Alberta

    NASA Astrophysics Data System (ADS)

    Diiwu, J.; Silins, U.; Kevin, B.; Anderson, A.

    2008-12-01

    Like many areas of the Rocky Mountains, Alberta's forests on the eastern slopes of the Rockies have been shaped by decades of successful fire suppression. These forests are at high risk to fire and large scale insect infestation, and climate change will continue to increase these risks. These headwaters forests provide the vast majority of usable surface water supplies to large region of the province, and large scale natural disasters can have dramatic effects on water quality and water availability. The population in the region has steadily increased and now this area is the main source water for many Alberta municipalities, including the City of Calgary, which has a population of over one million. In 2003 a fire burned 21,000 ha in the southern foothills area. The government land managers were concerned about the downstream implications of the fire and salvage operations, however there was very limited scientific information to guide the decision making. This led to establishment of the Southern Rockies Watershed Project, which is a partnership between Alberta Sustainable Resource Development, the provincial government department responsible for land management and the University of Alberta. After five years of data collection, the project has produced quantitative information that was not previously available about the effects of fire and management interventions such as salvage logging on headwaters and regional water quality. This information can be used to make decisions on forest operations, fire suppression, and post-fire salvage operations. In the past few years this project has captured the interest of large municipalities and water treatment researchers who are keen to investigate the potential implications of large natural disturbances to large and small drinking water treatment facilities. Examples from this project will be used to highlight the challenges and successes encountered while bridging the gap between science and land management policy.

  8. Sea-Level Rise Implications for Coastal Protection from Southern Mediterranean to the U.S.A. Atlantic Coast

    NASA Astrophysics Data System (ADS)

    Ismail, Nabil; Williams, Jeffress

    2013-04-01

    This paper presents an assessment of global sea level rise and the need to incorporate projections of rise into management plans for coastal adaptation. It also discusses the performance of a shoreline revetment; M. Ali Seawall, placed to protect the land against flooding and overtopping at coastal site, within Abu Qir Bay, East of Alexandria, Egypt along the Nile Delta coast. The assessment is conducted to examine the adequacy of the seawall under the current and progressive effects of climate change demonstrated by the anticipated sea level rise during this century. The Intergovernmental Panel on Climate Change (IPCC, 2007) predicts that the Mediterranean will rise 30 cm to 1 meter this century. Coastal zone management of the bay coastline is of utmost significance to the protection of the low agricultural land and the industrial complex located in the rear side of the seawall. Moreover this joint research work highlights the similarity of the nature of current and anticipated coastal zone problems, at several locations around the world, and required adaptation and protection measures. For example many barrier islands in the world such as that in the Atlantic and Gulf of Mexico coasts of the U.S., lowland and deltas such as in Italy and the Nile Delta, and many islands are also experiencing significant levels of erosion and flooding that are exacerbated by sea level rise. Global Climatic Changes: At a global scale, an example of the effects of accelerated climate changes was demonstrated. In recent years, the impacts of natural disasters are more and more severe on coastal lowland areas. With the threats of climate change, sea level rise storm surge, progressive storm and hurricane activities and potential subsidence, the reduction of natural disasters in coastal lowland areas receives increased attention. Yet many of their inhabitants are becoming increasingly vulnerable to flooding, and conversions of land to open ocean. These global changes were recently demonstrated in autumn 2010 when the storm Becky reached the Santander Bay, Spain. As reported by THESEUS, the FP-7 EU project (2009-2013), the peak of nearshore significant wave height was about 8 m, the storm surge reached 0.6 m, with tidal level of 90% of the tidal range. The latest storm in December 2010, which hit the Nile Delta and which was the severest in the last decades showed that generated surges, up to 1.0 m as well as a maximum of 7.5 m wave height in the offshore of Alexandria presented a major natural hazard in coastal zones in terms of wave run up and overtopping. Along the US Atlantic Coast, where Hurricane Sandy this autumn and Hurricane Irene in 2011 left chaos in their wakes, a perfect storm of rising sea levels and dense coastal development at high risk . Super storm Sandy sent a storm surge of 4-5 m onto New Jersey's and New York's fragile barrier island and urban shorelines, causing an estimated 70 billion (USD) in damages and widespread misery for coastal inhabitants. Sea Level Rise and Impact on Upgrade of Coastal Structures: Williams (2013) highlights in his recent paper that adaptation planning on national scales in the USA for projected sea-level rise of 0.5-2 m by A.D. 2100 is advisable. Further he points out that sea-level rise, as a major driving force of change for coastal regions, is becoming increasingly important as a hazard to humans and urban areas in the coastal zone worldwide as global climate change takes effect. During the 20th century, sea level began rising at a global average rate of 1.7 mm/yr (). The current average rise rate is 3.1 mm/yr, a 50% increase over the past two decades. Many regions are experiencing even greater rise rates due to local geophysical (e.g., Louisiana, Chesapeake Bay) and oceanographic (mid-Atlantic coast) forces. Further the Mississippi River Delta plain region of Louisiana has much higher than average rates of LRSL rise due to geologic factors such as subsidence and man-made alterations to the delta plain, wetlands, and coast. As a result the entire coast is highly erosional and highly vulnerable to sea-level rise and storms. Detailed mapping studies over the past two decades show that subject to sea-level rise, subsidence, frequent major storms, and reduced sediment budget. Sea-level rise, with high regional variability, is exhibiting acceleration and is expected to continue for centuries unless mitigation is enacted to reduce atmospheric carbon. Low lying coastal plain regions, deltas, and most islands are highly vulnerable. The assessment of Abu-Qir seawall included the review of the current-2011design and past upgrades since 1830. Hydrodynamic analyses were conducted to estimate wave height distributions, wave run up and overtopping over the seawall. Use has been made of the Modified ImSedTran-2D model (Ismail et.al, 2012) as well as universal design standards (EurOtop, 2008). Comparison of the predicted overtopping with the observed wave overtopping volumes during the 8hrs-2010 storm, allowed the verification of the used universal design tools. Based on the results for worst wave design scenarios and anticipated sea level rise after 50 years (50 cm), recommendations are given to increase the height of the seawall cap, to strengthen the beach top and back slope with a facility to drain storm water to increase coastal resilience. Recommendations: Protection of coastal fringes requires that new design alternatives to protect eroding lowland shorelines of deltas and barrier islands should be explored. These soft engineering alternatives are such as beach nourishment, sand dunes stabilization, and storm barriers. Use of integrated barrier island and coastal lagoons & wetlands would act as a buffer zone to defend main land. The sustainability of the integrated natural systems would require (1) barrier island and shoreline restoration (2) hydrologic and vegetation restoration of coastal lagoons, and (3) relocation of development in highly vulnerable areas. Such adaptation planning and restoration projects will require a major undertaking by national governments and international institutions. Joint research projects between international organizations such as: USA research centers ( USGS, NOAA, Corps of Engineers), EU sponsored project groups, EU coastal marine centers as well as other world wide coastal research institutes (CoRI, Alexandria) are encouraged to advance the state of the art on managing coasts to adapt to sea level rise employing cost-effective coastal protection technologies. References 1.Williams, S.J.,"Sea-Level Rise Implications for Coastal Regions", Journal of Coastal Research, Vol. 63, 2013. 2.Ismail, N.,Wiegel, R., "Sustainable Solutions for Coastal Zone Management of Lowland and River Delta Coastlines", Proc. International Conference- Littoral 2012, Ostende, Belgium, November 27-29, 2012. 3.Ismail, N., Iskander, M., and El-Sayed, W. "Assessment of Coastal Flooding at Southern Mediterranean with Global Outlook for Lowland Coastal Zones", Proc. International Conference on Coastal Engineering, ASCE, July 1-6, 2012, Santander, Spain. 4.Moser, S. C., Williams,J.S., and Boesch, D. F., " Wicked Challenges at Land's End: Managing Coastal Vulnerability Under Climate Change'', Annual. Review of Environmental Resources, 37:51-78, 2012.

  9. Paleomagnetic results from the Cambrian and Ordovician sediments of Bornholm (Denmark) and Southern Sweden and paleogeographical implications for Baltica

    NASA Astrophysics Data System (ADS)

    Lewandowski, Marek; Abrahamsen, Niels

    2003-11-01

    If apparent polar wander paths (APWP) cross, the question arises how to prove the older magnetization to be primary and not just a younger overprint. This problem is typically met in areas affected by percolating mineralizing fluids and/or heating due to a younger regional igneous activity. The Permian magnetic overprint is the classical example. Earlier paleomagnetic studies over the Lowermost Cambrian Nekso Sandstone Fm (NSF) of Bornholm (Denmark) yielded a characteristic remanent magnetization (ChRM) similar to the Permian directions for Baltica. Since a possible reason could be a chemical overprint, we checked whether this phenomenon did take place on a regional scale. Some samples therefore were collected from other Lower Cambrian clastics of Bornholm and Southern Scandinavia. In result we show that the well-grouped and stable ChRM of the NSF contrasts with fairly chaotic, soft, and badly preserved magnetizations of the Balka, Hardeberga, Mickwitzia, and Lingulid sandstones of Bornholm and Southern Sweden, thus not indicating widespread paleomagnetic overprint. We demonstrate that the ChRM of the NSF is most probably of syndepositional/early diagenetic origin and its similarity to the Permian direction for Baltica is only casual. We propose a normal polarity and a near-equatorial position on the Southern Hemisphere for Baltica in the early Cambrian time, as well as a more complicated trend of the APWP for this paleocontinent than envisaged by other authors. Paleomagnetic results from the Arenigian limestones of the Laesaa Formation (Bornholm) that yield excellently defined but most probably only secondary components are also presented.

  10. Interseismic Strain Accumulation in the Imperial Valley and Implications for Triggering of Large Earthquakes in Southern California

    NASA Astrophysics Data System (ADS)

    Crowell, B. W.; Bock, Y.; Sandwell, D. T.

    2009-12-01

    From February, 2008 to March, 2009, we performed three rapid-static Global Positioning System (GPS) surveys of 115 geodetic monuments stretching from the United States-Mexico border into the Coachella Valley using the method of instantaneous positioning. The monuments are located in key areas near the Imperial, Superstition Hills, San Jacinto, San Andreas and Brawley Faults with nominal baselines generally less than 10 km. We perform a bicubic spline interpolation on the crustal motion vectors from the campaign measurements and 1005 continuous GPS monuments in western North America and solve for the velocity gradient tensor to look at the maximum shear strain, dilatation and rotation rates in the Imperial Valley. We then compare our computed strain field to that computed using the Southern California Earthquake Center Crustal Motion Map 3.0, which extends through 2003 and includes 840 measurements. We show that there is an interseismic strain transient that corresponds to an increase in the maximum shear strain rate of 0.7 μstrain/yr near Obsidian Buttes since 2003 along a fault referred to as the Obsidian Buttes Fault (OBF). A strong subsidence signal of 27 mm/yr and a left-lateral increase of 10 mm/yr are centered along the OBF. Changes in the dilatation and rotation rates confirm the increase in left-lateral motion, as well as infer a strong increase in spreading rate in the southern Salton Sea. The increase in spreading rate has caused an accelerated slip rate along the southern San Andreas near Durmid Hill as evidenced by continuous GPS, which has the potential for earthquake triggering.

  11. The Discovery of New Deep-Sea Hydrothermal Vent Communities in the Southern Ocean and Implications for Biogeography

    PubMed Central

    Rogers, Alex D.; Tyler, Paul A.; Connelly, Douglas P.; Copley, Jon T.; James, Rachael; Larter, Robert D.; Linse, Katrin; Mills, Rachel A.; Garabato, Alfredo Naveira; Pancost, Richard D.; Pearce, David A.; Polunin, Nicholas V. C.; German, Christopher R.; Shank, Timothy; Boersch-Supan, Philipp H.; Alker, Belinda J.; Aquilina, Alfred; Bennett, Sarah A.; Clarke, Andrew; Dinley, Robert J. J.; Graham, Alastair G. C.; Green, Darryl R. H.; Hawkes, Jeffrey A.; Hepburn, Laura; Hilario, Ana; Huvenne, Veerle A. I.; Marsh, Leigh; Ramirez-Llodra, Eva; Reid, William D. K.; Roterman, Christopher N.; Sweeting, Christopher J.; Thatje, Sven; Zwirglmaier, Katrin

    2012-01-01

    Since the first discovery of deep-sea hydrothermal vents along the Galápagos Rift in 1977, numerous vent sites and endemic faunal assemblages have been found along mid-ocean ridges and back-arc basins at low to mid latitudes. These discoveries have suggested the existence of separate biogeographic provinces in the Atlantic and the North West Pacific, the existence of a province including the South West Pacific and Indian Ocean, and a separation of the North East Pacific, North East Pacific Rise, and South East Pacific Rise. The Southern Ocean is known to be a region of high deep-sea species diversity and centre of origin for the global deep-sea fauna. It has also been proposed as a gateway connecting hydrothermal vents in different oceans but is little explored because of extreme conditions. Since 2009 we have explored two segments of the East Scotia Ridge (ESR) in the Southern Ocean using a remotely operated vehicle. In each segment we located deep-sea hydrothermal vents hosting high-temperature black smokers up to 382.8°C and diffuse venting. The chemosynthetic ecosystems hosted by these vents are dominated by a new yeti crab (Kiwa n. sp.), stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in vent ecosystems in other oceans, including polychaete worms (Siboglinidae), bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR vents. These groups, except the Siboglinidae, possess planktotrophic larvae, rare in Antarctic marine invertebrates, suggesting that the environmental conditions of the Southern Ocean may act as a dispersal filter for vent taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic vent ecosystems represent a new vent biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea hydrothermal vents globally indicate that vent biogeography is more complex than previously recognised. PMID:22235194

  12. The discovery of new deep-sea hydrothermal vent communities in the southern ocean and implications for biogeography.

    PubMed

    Rogers, Alex D; Tyler, Paul A; Connelly, Douglas P; Copley, Jon T; James, Rachael; Larter, Robert D; Linse, Katrin; Mills, Rachel A; Garabato, Alfredo Naveira; Pancost, Richard D; Pearce, David A; Polunin, Nicholas V C; German, Christopher R; Shank, Timothy; Boersch-Supan, Philipp H; Alker, Belinda J; Aquilina, Alfred; Bennett, Sarah A; Clarke, Andrew; Dinley, Robert J J; Graham, Alastair G C; Green, Darryl R H; Hawkes, Jeffrey A; Hepburn, Laura; Hilario, Ana; Huvenne, Veerle A I; Marsh, Leigh; Ramirez-Llodra, Eva; Reid, William D K; Roterman, Christopher N; Sweeting, Christopher J; Thatje, Sven; Zwirglmaier, Katrin

    2012-01-01

    Since the first discovery of deep-sea hydrothermal vents along the Galápagos Rift in 1977, numerous vent sites and endemic faunal assemblages have been found along mid-ocean ridges and back-arc basins at low to mid latitudes. These discoveries have suggested the existence of separate biogeographic provinces in the Atlantic and the North West Pacific, the existence of a province including the South West Pacific and Indian Ocean, and a separation of the North East Pacific, North East Pacific Rise, and South East Pacific Rise. The Southern Ocean is known to be a region of high deep-sea species diversity and centre of origin for the global deep-sea fauna. It has also been proposed as a gateway connecting hydrothermal vents in different oceans but is little explored because of extreme conditions. Since 2009 we have explored two segments of the East Scotia Ridge (ESR) in the Southern Ocean using a remotely operated vehicle. In each segment we located deep-sea hydrothermal vents hosting high-temperature black smokers up to 382.8°C and diffuse venting. The chemosynthetic ecosystems hosted by these vents are dominated by a new yeti crab (Kiwa n. sp.), stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in vent ecosystems in other oceans, including polychaete worms (Siboglinidae), bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR vents. These groups, except the Siboglinidae, possess planktotrophic larvae, rare in Antarctic marine invertebrates, suggesting that the environmental conditions of the Southern Ocean may act as a dispersal filter for vent taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic vent ecosystems represent a new vent biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea hydrothermal vents globally indicate that vent biogeography is more complex than previously recognised. PMID:22235194

  13. Os, Sr, Nd, and Pb isotope systematics of southern African peridotite xenoliths - Implications for the chemical evolution of subcontinental mantle

    NASA Technical Reports Server (NTRS)

    Walker, R. J.; Carlson, R. W.; Shirey, S. B.; Boyd, F. R.

    1989-01-01

    Isotope analyses of Os, Sr, Nd, and Pb elements were caried out on twelve peridotite xenoliths from the Jagersfontein, Letseng-la-terae, Thaba Patsoa, Mothae, and Premier kimberlites of southern Africa, to investigate the timing and the nature of melt extraction from the continental lithosphere and its relation to the continent formation and stabilization. The distinct Os and Pb isotopic characteristics found in these samples suggested that both the low- and the high-temperature peridotites reside in an ancient stable lithospheric 'keel' to the craton that has been isolated from chemical exchange with the sublithospheric mantle for time periods in excess of 2 Ga.

  14. Occurrence of Sudan I in paprika fruits caused by agricultural environmental contamination.

    PubMed

    Lian, Yunhe; Gao, Wei; Zhou, Li; Wu, Naiying; Lu, Qingguo; Han, Wenjie; Tie, Xiaowei

    2014-05-01

    Current research has demonstrated the presence of sub parts per billion levels of Sudan dye in paprika fruits during the vegetation process, which is difficult to understand on the basis of the conventional concept of cross-contamination or malicious addition. Detailed surveys on Sudan dyes I-IV in paprika fruits, soils, and agronomic materials used from seven fields of Xinjiang (China) were conducted to investigate the natural contamination. Results revealed that Sudan dyes II-IV were never detected and that Sudan I existed in almost all samples except for the mulching film and irrigation water. The higher total amount of Sudan I in soils, pesticides, and fertilizers compared to coated seeds indicated the combination of Sudan I-contaminated soils and application of Sudan I-containing agronomic materials constitutes a major source of 0.18-2.52 μg/kg levels of Sudan I in fruits during the growth period. The study offers a more reasonable explanation for the previously observed Sudan I in paprika fruits. PMID:24766082

  15. Hydroclimate implications of thermocline variability in the southern South China Sea over the past 180,000 yr

    NASA Astrophysics Data System (ADS)

    Dong, Liang; Li, Li; Li, Qianyu; Wang, Hui; Zhang, Chuanlun L.

    2015-03-01

    Based on core-top calibration, the TEX 86H-derived temperature has been considered as representing subsurface sea temperature (SSST), and the difference between the U37K‧-derived sea-surface temperature (SST) and the TEX 86H-derived SSST can be used to reflect the depth of thermocline (DOT) in the South China Sea region (Jia et al., 2012). We evaluated the DOT dynamics in late Quaternary records using this approach on paired analysis of samples from core MD05-2896/7 in the southern South China Sea. The reconstructed DOT over the last 180,000 yr (180 ka) displays a shoaling trend in glacial periods, which may be attributed to the strengthened cyclonic gyre by the enhanced East Asian winter monsoon and Walker circulation with prominent La Niña-like state, and vice versa in interglacial periods corresponding to reduced winter monsoon with enhanced El Niño-like state. These upper-water thermal variations testify that enhanced winter monsoon was the direct cause of an uplifted local thermocline during glacial or La Niña-like states with strengthened cyclonic gyre due to positive wind stress curl in the southern South China Sea. Our results provide insights into the relationship between monsoon and ENSO on both glacial and millennial time scales.

  16. Variability in transport pathways on and around the South Georgia shelf, Southern Ocean: Implications for recruitment and retention

    NASA Astrophysics Data System (ADS)

    Young, Emma F.; Thorpe, Sally E.; Banglawala, Neelofer; Murphy, Eugene J.

    2014-01-01

    The waters around South Georgia are among the most productive in the Southern Ocean, with zooplankton populations close to the island, in particular Antarctic krill, supporting vast colonies of higher predators. However, our understanding of the processes governing variability in the supply of these food resources is limited by the poor spatial and temporal resolution of available data. Here, we use a numerical modeling approach to examine the underlying physical processes driving the recruitment and retention of zooplankton to the South Georgia shelf. Variability in the magnitude and spatial distribution of recruitment was dominated by the proximity and orientation of the southern Antarctic Circumpolar Current front to the shelf edge. Shelf retention was highest for source sites on the southwest shelf, with the main transport routes off the shelf to the north and northwest. Retention was lowest in the austral summer and winter; in summer increased glacial melt drives stronger off-shelf near-surface currents, while in winter, stronger winds lead to an increase in off-shelf transport. Of particular note was the prediction of a significant increase in retention for particles released throughout the shelf in April and July 2000. This period coincided with the development of pronounced anticlockwise shelf flows, associated with horizontal density gradients due to reduced wind mixing of shelf waters, and differences between shelf and oceanic waters, which significantly reduced off-shelf transport rates. Such findings are crucial for understanding the influence of variability in physical processes on the ecosystem at South Georgia.

  17. Middle Miocene paleoaltimetry of southern Tibet: Implications for the role of mantle thickening and delamination in the Himalayan orogen

    NASA Astrophysics Data System (ADS)

    Currie, Brian S.; Rowley, David B.; Tabor, Neil J.

    2005-03-01

    The stable isotope composition of pedogenic and early diagenetic carbonates from the Oiyug Basin of southern Tibet allows model estimates of the paleoaltimetry of the Tibetan Plateau for the middle Miocene. Pedogenic calcium carbonate nodules have average δ18Occ values of -19.6‰, whereas nodular lacustrine dolomites range in composition from -7.6‰ to -5.5‰. The most negative of the carbonate isotope values can be used to constrain the oxygen isotope composition of paleoprecipitation, from which model estimates of paleoaltimetry can be made. Model results indicate that the southern Tibetan Plateau achieved elevations of ˜5200 +1370/-605 m by at least 15 Ma. Our results are identical within uncertainty to previous workers' paleoelevation estimates based on Oiyug Basin fossil floral physiognomy. This is the first time that two paleoaltimeters have been directly compared and are in accord. Collectively, these data strongly support tectonic models in which thickening of mantle lithosphere beneath the domain of crustal thickening and subsequent detachment of the mantle lithosphere plays an indiscernible role in the elevation history of this part of the Himalaya-Tibet orogenic system.

  18. Thrust faults of southern Diamond Mountains, central Nevada: Implications for hydrocarbons in Diamond Valley and at Yucca Mountain

    SciTech Connect

    French, D.E.

    1993-04-01

    Overmature Mississippian hydrocarbon source rocks in the southern Diamond Mountains have been interpreted to be a klippe overlying less mature source rocks and represented as an analogy to similar conditions near Yucca Mountain (Chamberlain, 1991). Geologic evidence indicates an alternative interpretation. Paleogeologic mapping indicates the presence of a thrust fault, referred to here as the Moritz Nager Thrust Fault, with Devonian rocks emplaced over Permian to Mississippian strata folded into an upright to overturned syncline, and that the overmature rocks of the Diamond Mountains are in the footwall of this thrust. The upper plate has been eroded from most of the Diamond Mountains but remnants are present at the head of Moritz Nager Canyon and at Sentinel Mountain. Devonian rocks of the upper plate comprised the earliest landslide megabreccia. Later, megabreccias of Pennsylvanian and Permian rocks of the overturned syncline of the lower plate were deposited. By this interpretation the maturity of lower-plate source rocks in the southern Diamond Mountains, which have been increased by tectonic burial, is not indicative of conditions in Diamond Valley, adjacent to the west, where upper-plate source rocks might be present in generating conditions. The interpretation that overmature source rocks of the Diamond Mountains are in a lower plate rather than in a klippe means that this area is an inappropriate model for the Eleana Range near Yucca Mountain.

  19. Magnetostratigraphy of syntectonic growth strata and implications for the late Cenozoic deformation in the Baicheng Depression, Southern Tian Shan

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiliang; Sun, Jimin; Tian, Zhonghua; Gong, Zhijun

    2016-03-01

    The collision between India and Eurasia in the Cenozoic has caused a series of intracontinental deformation in the foreland basins of Tian Shan, but there are debates about the timing of tectonic deformation and the relationship between tectonic uplift and sediment accumulation in the foreland basins. Based on the magnetostratigraphy of growth strata in the Baicheng Depression, Southern Tian Shan, we suggest that an episode of crustal shortening in the late Cenozoic evidenced by syntectonic growth strata in the Kelasu-Yiqikelike structural belt (KYSB) initiated at ∼5.3 Ma, since then the sedimentation rate accelerated abruptly and coarse molasse deposits accumulated. Combined with the results of growth strata on both flanks of Tian Shan and the fact that the Xiyu Formation on the southern limb of the Kasangtuokai Anticline was involved into the growth strata, we conclude that the period from ∼7-5 Ma to the early Pleistocene was one of the important episodes of intracontinental deformation in the foreland basins of Tian Shan, as a response to the Cenozoic collision between India and Eurasia.

  20. A comparison of observed and modeled surface waves in southern Lake Michigan and the implications for models of sediment resuspension.

    SciTech Connect

    Hawley, N.; Lesht, B. M.; Schwab, D. J.; Environmental Research; Great Lakes Environmental Research Lab

    2004-06-25

    Subsurface pressure sensors were used to make measurements of surface waves during 18 deployments in southern Lake Michigan between 1998 and 2000. Most of the observations were made during the unstratified period (November--May) in water depths between 10 and 55 m. The observations (as well as those obtained from the National Data Buoy Center (NDBC) buoy 45007, which is located in the middle of the southern basin of the lake) were compared to the results obtained from the Great Lakes Environmental Research Laboratory (GLERL)-Donelan wave model implemented on a 2-km grid. The results show that the wave model does a good job of calculating the wave heights, but consistently underestimates the wave periods. In over 80% of the cases the bottom stresses calculated from both the observations and the wave model results agree as to whether or not resuspension occurs, but over 70% of this agreement is for cases when resuspension does not occur; both stresses predict resuspension about 6% of the time. Since the bottom stresses calculated from the model results are usually lower than those calculated from the observations, resuspension estimates based on the wave model parameters are also lower than those calculated from the observed waves.

  1. Implications of Nubian-Like Core Reduction Systems in Southern Africa for the Identification of Early Modern Human Dispersals

    PubMed Central

    Phillips, Natasha

    2015-01-01

    Lithic technologies have been used to trace dispersals of early human populations within and beyond Africa. Convergence in lithic systems has the potential to confound such interpretations, implying connections between unrelated groups. Due to their reductive nature, stone artefacts are unusually prone to this chance appearance of similar forms in unrelated populations. Here we present data from the South African Middle Stone Age sites Uitpanskraal 7 and Mertenhof suggesting that Nubian core reduction systems associated with Late Pleistocene populations in North Africa and potentially with early human migrations out of Africa in MIS 5 also occur in southern Africa during early MIS 3 and with no clear connection to the North African occurrence. The timing and spatial distribution of their appearance in southern and northern Africa implies technological convergence, rather than diffusion or dispersal. While lithic technologies can be a critical guide to human population flux, their utility in tracing early human dispersals at large spatial and temporal scales with stone artefact types remains questionable. PMID:26125972

  2. Scale-up of a programme for malaria vector control using long-lasting insecticide-treated nets: lessons from South Sudan

    PubMed Central

    Remijo, Constantino D; Pasquale, Harriet; Baba, Samson P; Lako, Richard L

    2014-01-01

    Abstract Problem Long-lasting insecticidal nets (LLINs) are important tools in malaria control. South Sudan, like many other endemic countries, has struggled to improve LLIN coverage and utilization. Approach In 2006, Southern Sudan – known as South Sudan after independence in 2011 – initiated a strategic plan to increase LLIN coverage so that at least 60% of households had at least one LLIN each. By 2008, the target coverage was 80% of households and the Global Fund had financed a phased scale-up of LLIN distribution in the region. Local setting South Sudan’s entire population is considered to be at risk of malaria. Poor control of the vectors and the large-scale movements of returnees, internally displaced people and refugees have exacerbated the problem. Relevant changes By 2012, approximately 8.0 million LLINs had been distributed in South Sudan. Between 2006 and 2009, the percentage of households possessing at least one LLIN increased from about 12% to 53% and LLIN utilization rates increased from 5 to 25% among children younger than 5 years and from 5 to 36% among pregnant women. The number of recorded malaria cases increased from 71 948 in 2008 to 1 198 357 in 2012. Lessons learnt In post-conflict settings, a phased programme for the national scale-up of LLIN coverage may not have a substantial impact. A nationwide campaign that is centrally coordinated and based on sound guidelines may offer greater benefits. A strong partnership base and effective channels for the timely and supplementary deployment of LLINs may be essential for universal coverage. PMID:24700997

  3. Logistics of Guinea Worm Disease Eradication in South Sudan

    PubMed Central

    Jones, Alexander H.; Becknell, Steven; Withers, P. Craig; Ruiz-Tiben, Ernesto; Hopkins, Donald R.; Stobbelaar, David; Makoy, Samuel Yibi

    2014-01-01

    From 2006 to 2012, the South Sudan Guinea Worm Eradication Program reduced new Guinea worm disease (dracunculiasis) cases by over 90%, despite substantial programmatic challenges. Program logistics have played a key role in program achievements to date. The program uses disease surveillance and program performance data and integrated technical–logistical staffing to maintain flexible and effective logistical support for active community-based surveillance and intervention delivery in thousands of remote communities. Lessons learned from logistical design and management can resonate across similar complex surveillance and public health intervention delivery programs, such as mass drug administration for the control of neglected tropical diseases and other disease eradication programs. Logistical challenges in various public health scenarios and the pivotal contribution of logistics to Guinea worm case reductions in South Sudan underscore the need for additional inquiry into the role of logistics in public health programming in low-income countries. PMID:24445199

  4. The Status of Women in Physics in Sudan

    NASA Astrophysics Data System (ADS)

    Abdelbagi, Abdrazig M.; Sirelkhatim, Amna H.; Abdelrahman, Wafaa S.; Osman, Mai E.; Shatir, Tahani S.

    2009-04-01

    The progress of women in physics education in the last five years was surveyed in the six top universities in Sudan. The data reveal great increases in the number of females studying undergraduate physics. Most were studying experimental physics rather than theoretical physics, especially the laser and electronics fields. It appears undergraduate laboratory experiments are an important factor in attracting women to physics. Our survey found that girls are encouraged to study physics at the high school level. However, the data also showed that the fewer tendencies to study physics among the women after high school are due to the limited job opportunities and low income of teachers. Postgraduate physics study is handicapped by lack of institutions, financial constraints, and lack of qualified advisors. Improvement of education systems and new ways of teaching will have great influences on attracting women to physics in Sudan.

  5. Seroprevalence of rubella among pregnant women in Khartoum state, Sudan.

    PubMed

    Adam, O; Makkawi, T; Kannan, A; Osman, M E

    2013-09-01

    Rubella vaccine is not included in the Sudanese national immunization programme, and data on prevalence of rubella among women of childbearing age are inadequate. The objective of this cross-sectional study was to determine the seroprevalence of rubella among pregnant women in Khartoum state, Sudan. A total of 500 pregnant women who visited 7 antenatal clinics from November 2008 to March 2009 were examined for the presence of rubella IgG antibodies using ELISA. Rubella IgG antibodies were detected in 95.1% (95% Cl: 93.2%-97.0%) of women. This seroprevalence was significantly associated with education level, but not with age, residence area, occupation or parity. We presume this high seroprevalence indicates a high circulation of wild rubella virus in Khartoum state. Similar studies in other Sudanese states would be important for informing a decision to introduce rubella vaccine to Sudan. PMID:24313044

  6. The 2007 Rift Valley fever outbreak in Sudan.

    PubMed

    Hassan, Osama Ahmed; Ahlm, Clas; Sang, Rosemary; Evander, Magnus

    2011-09-01

    Rift Valley fever (RVF) is a neglected, emerging, mosquito-borne disease with severe negative impact on human and animal health and economy. RVF is caused by RVF virus (RVFV) affecting humans and a wide range of animals. The virus is transmitted through bites from mosquitoes and exposure to viremic blood, body fluids, or tissues of infected animals. During 2007 a large RVF outbreak occurred in Sudan with a total of 747 confirmed human cases including 230 deaths (case fatality 30.8%); although it has been estimated 75,000 were infected. It was most severe in White Nile, El Gezira, and Sennar states near to the White Nile and the Blue Nile Rivers. Notably, RVF was not demonstrated in livestock until after the human cases appeared and unfortunately, there are no records or reports of the number of affected animals or deaths. Ideally, animals should serve as sentinels to prevent loss of human life, but the situation here was reversed. Animal contact seemed to be the most dominant risk factor followed by animal products and mosquito bites. The Sudan outbreak followed an unusually heavy rainfall in the country with severe flooding and previous studies on RVF in Sudan suggest that RVFV is endemic in parts of Sudan. An RVF outbreak results in human disease, but also large economic loss with an impact beyond the immediate influence on the directly affected agricultural producers. The outbreak emphasizes the need for collaboration between veterinary and health authorities, entomologists, environmental specialists, and biologists, as the best strategy towards the prevention and control of RVF. PMID:21980543

  7. Value and cost of children in rural Sudan.

    PubMed

    Saghayroun, A A

    1983-12-01

    In this study the major dimensions of the value and cost of children are explained. It is argued that the nature of the production process in rural Sudan is the essential determinant of family size. This study depends mainly upon statistics gathered through surveys conducted in El Sawagi villages in Kassala province between January and May 1979. Children are needed to help on the family farm, looking after cattle and other animals in rural areas or to join the family in business inside and outside the home, and are thus considered as a cheap source of labor under the rural economy in the Sudan. In El Sawagi villages children are seen not only as a prime source of social security for aging parents but also as a source of income right from their childhood. It is because of the agrarian nature of the Sudan and because the system of agriculture is still mainly primitive and subsistence orientated, that children are valuable assets on the large scheme or family farms. Even though children may contribute little labor when the sum is averaged out over the whole year, their labor may be crucial for the poor, at times of peak labor demand. The favorite number of children for a family in El Sawagi villages is more than 4. The cost of rearing and educating a child has probably not yet entered into their calculations. At present, it is still economically beneficial to poor rural families to have a large number of children, although it is not to Sudan's economic benefit. Other social reasons for having children are discussed as well as the disadvantages of having many children. PMID:12312894

  8. Evidence for and implications of sedimentary diapirism and mud volcanism in the southern Utopia highland-lowland boundary plain, Mars

    USGS Publications Warehouse

    Skinner, J.A., Jr.; Tanaka, K.L.

    2007-01-01

    Several types of spatially associated landforms in the southern Utopia Planitia highland-lowland boundary (HLB) plain appear to have resulted from localized geologic activity, including (1) fractured rises, (2) elliptical mounds, (3) pitted cones with emanating lobate materials, and (4) isolated and coalesced cavi (depressions). Stratigraphic analysis indicates these features are Hesperian or younger and may be associated with resurfacing that preferentially destroyed smaller (< 8 ?? km diameter) impact craters. Based on landform geomorphologies and spatial distributions, the documented features do not appear to be specifically related to igneous or periglacial processes or the back-wasting and erosion of the HLB scarp. We propose that these features are genetically related to and formed by sedimentary (mud) diapirs that ascended from zones of regionally confined, poorly consolidated, and mechanically weak material. We note morphologic similarities between the mounds and pitted cones of the southern Utopia boundary plain and terrestrial mud volcanoes in the Absheron Peninsula, Azerbaijan. These analogs provide a context for understanding the geological environments and processes that supported mud diapir-related modification of the HLB. In southern Utopia, mud diapirs near the Elysium volcanic edifice may have resulted in laccolith-like intrusions that produced the fractured rises, while in the central boundary plain mud diapirs could have extruded to form pitted cones, mounds, and lobate flows, perhaps related to compressional stresses that account for wrinkle ridges. The removal of material a few kilometers deep by diapiric processes may have resulted in subsidence and deformation of surface materials to form widespread cavi. Collectively, these inferences suggest that sedimentary diapirism and mud volcanism as well as related surface deformations could have been the dominant Hesperian mechanisms that altered the regional boundary plain. We discuss a model in which detritus would have accumulated thickly in the annular spaces between impact-generated structural rings of Utopia basin. We envision that these materials, and perhaps buried ejecta of Utopia basin, contained volatile-rich, low-density material that could provide the source material for the postulated sedimentary diapirs. Thick, water-rich, low-density sediments buried elsewhere along the HLB and within the lowland plains may account for similar landforms and resurfacing histories. ?? 2006 Elsevier Inc. All rights reserved.

  9. Kinematics and age of Early Tertiary trench parallel volcano-tectonic lineaments in southern Mexico: Tectonic implications

    NASA Astrophysics Data System (ADS)

    Martini, M.; Ferrari, L.; Lopez Martinez, M.; Cerca Martinez, M.; Serrano Duran, L.

    2007-05-01

    We present new geological, structural, and geochronological data that constrain the timing and geometry of Early Tertiary strike slip deformation in southwestern Mexico and its relation with the concurrent magmatic activity. Geologic mapping in Guerrero and Michoacan States documented two regional WNW trending volcano-tectonic lineaments sub parallel to the present trench. The southernmost lineament runs for ~140 km from San Miguel Totolapan area (NW Guerrero) to Sanchiqueo (SE Michoacan), and passes through Ciudad Altamirano. Its southeastern part is marked by the alignment of at least eleven silicic to intermediate major domes as well as by the course of the Balsas River. The northwestern part of the lineament is characterized by ductile left lateral shear zones in Early Tertiary plutonic rocks observed in the Rio Chiquito valley. Domes near Ciudad Altamirano are unaffected by ductile shearing and yielded a ~42 Ma 40Ar/39Ar age, setting a minimum age for this deformation. The northern volcano-tectonic lineament runs for ~190 km between the areas of Huitzuco in northern Guerrero and the southern part of the Tzitzio fold in eastern Michoacan. The Huautla, Tilzapotla, Taxco, La Goleta and Nanchititla silicic centers (all in the range 37-34 Ma) are emplaced along this lineament, which continues to the WNW trough a mafic dike swarm exposed north of Tiquicheo (37-35 Ma) and the Purungueo subvolcanic body (~42 Ma). These rocks, unaffected by ductile shearing, give a minimum age of deformation similar to the southern Totolapan-Sanquicheo lineament. Post ~42 Ma deformation is essentially brittle and is characterized by several left lateral and right lateral transcurrent faults with typical Riedel patterns. Other trench-parallel left lateral shear zones active in pre-Oligocene times were recently reported in western Oaxaca. The recognizing of Early Tertiary trench-parallel and left-lateral ductile shearing in internal areas of southern Mexico suggest a field of widely distributed flow and shear zones with relatively small individual displacement that might represent an immature stage of the developing North American-Caribbean plate boundary. The documented transition from ductile to brittle deformation and the localization of shearing and volcanism in the Late Eocene may be related to the focusing of inter-plate deformation in a discrete left lateral transcurrent North America-Caribbean boundary. The opening of the Cayman Through at ~49 Ma may have accelerated this process.

  10. Focal mechanisms in the southern Aegean from temporary seismic networks - implications for the regional stress field and ongoing deformation processes

    NASA Astrophysics Data System (ADS)

    Friederich, W.; Brstle, A.; Kperkoch, L.; Meier, T.; Lamara, S.; Egelados Working Group

    2014-05-01

    The lateral variation of the stress field in the southern Aegean plate and the subducting Hellenic slab is determined from recordings of seismicity obtained with the CYCNET and EGELADOS networks in the years from 2002 to 2007. First motions from 7000 well-located microearthquakes were analysed to produce 540 well-constrained focal mechanisms. They were complemented by another 140 derived by waveform matching of records from larger events. Most of these earthquakes fall into 16 distinct spatial clusters distributed over the southern Aegean region. For each cluster, a stress inversion could be carried out yielding consistent estimates of the stress field and its spatial variation. At crustal levels, the stress field is generally dominated by a steeply dipping compressional principal stress direction except in places where coupling of the subducting slab and overlying plate come into play. Tensional principal stresses are generally subhorizontal. Just behind the forearc, the crust is under arc-parallel tension whereas in the volcanic areas around Kos, Columbo and Astypalea tensional and intermediate stresses are nearly degenerate. Further west and north, in the Santorini-Amorgos graben and in the area of the islands of Mykonos, Andros and Tinos, tensional stresses are significant and point around the NW-SE direction. Very similar stress fields are observed in western Turkey with the tensional axis rotated to NNE-SSW. Intermediate-depth earthquakes below 100 km in the Nisyros region indicate that the Hellenic slab experiences slab-parallel tension at these depths. The direction of tension is close to east-west and thus deviates from the local NW-oriented slab dip presumably owing to the segmentation of the slab. Beneath the Cretan sea, at shallower levels, the slab is under NW-SE compression. Tensional principal stresses in the crust exhibit very good alignment with extensional strain rate principal axes derived from GPS velocities except in volcanic areas, where both appear to be unrelated, and in the forearc where compressional principal stresses are very well aligned with compressional principal strain rates. This finding indicates that, except for volcanic areas, microseismic activity in the southern Aegean is not controlled by small-scale local stresses but rather reflects the regional stress field. The lateral and depth variations of the stress field reflect the various agents that influence tectonics in the Aegean: subduction of the Hellenic slab, incipient collision with continental African lithosphere, roll back of the slab in the southeast, segmentation of the slab, arc volcanism and extension of the Aegean crust.

  11. Evidence for and implications of sedimentary diapirism and mud volcanism in the southern Utopia highland lowland boundary plain, Mars

    NASA Astrophysics Data System (ADS)

    Skinner, James A.; Tanaka, Kenneth L.

    2007-01-01

    Several types of spatially associated landforms in the southern Utopia Planitia highland-lowland boundary (HLB) plain appear to have resulted from localized geologic activity, including (1) fractured rises, (2) elliptical mounds, (3) pitted cones with emanating lobate materials, and (4) isolated and coalesced cavi (depressions). Stratigraphic analysis indicates these features are Hesperian or younger and may be associated with resurfacing that preferentially destroyed smaller ( <8 km diameter) impact craters. Based on landform geomorphologies and spatial distributions, the documented features do not appear to be specifically related to igneous or periglacial processes or the back-wasting and erosion of the HLB scarp. We propose that these features are genetically related to and formed by sedimentary (mud) diapirs that ascended from zones of regionally confined, poorly consolidated, and mechanically weak material. We note morphologic similarities between the mounds and pitted cones of the southern Utopia boundary plain and terrestrial mud volcanoes in the Absheron Peninsula, Azerbaijan. These analogs provide a context for understanding the geological environments and processes that supported mud diapir-related modification of the HLB. In southern Utopia, mud diapirs near the Elysium volcanic edifice may have resulted in laccolith-like intrusions that produced the fractured rises, while in the central boundary plain mud diapirs could have extruded to form pitted cones, mounds, and lobate flows, perhaps related to compressional stresses that account for wrinkle ridges. The removal of material a few kilometers deep by diapiric processes may have resulted in subsidence and deformation of surface materials to form widespread cavi. Collectively, these inferences suggest that sedimentary diapirism and mud volcanism as well as related surface deformations could have been the dominant Hesperian mechanisms that altered the regional boundary plain. We discuss a model in which detritus would have accumulated thickly in the annular spaces between impact-generated structural rings of Utopia basin. We envision that these materials, and perhaps buried ejecta of Utopia basin, contained volatile-rich, low-density material that could provide the source material for the postulated sedimentary diapirs. Thick, water-rich, low-density sediments buried elsewhere along the HLB and within the lowland plains may account for similar landforms and resurfacing histories.

  12. Analysis of energy-saving potential in residential buildings in Xiamen City and its policy implications for southern China

    NASA Astrophysics Data System (ADS)

    Guo, Fei

    The buildings sector is the largest energy-consuming sector in the world. Residential buildings consume about three-quarters of the final energy in the buildings sector. Promoting residential energy savings is in consequence critical for addressing many energy-use-related environmental challenges, such as climate change and air pollution. Given China's robust economic growth and fast urbanization, it is now a critical time to develop policy interventions on residential energy use in the nation. With this as a background, this dissertation explores effective policy intervention opportunities in southern China through analyzing the residential energy-saving potential, using the city of Xiamen as a case study. Four types of residential energy-saving potential are analyzed: technical potential, economic potential, maximum achievable potential (MAP), and possible achievable potential (PAP). Of these, the first two types are characterized as static theoretical evaluation, while the last two represent dynamic evaluation within a certain time horizon. The achievable potential analyses are rarely seen in existing literature. The analytical results reveal that there exists a significant technical potential for residential energy savings of about 20.9-24.9% in the city of Xiamen. Of the technical potential, about two-thirds to four-fifths are cost-effective from the government or society perspective. The cost-effectiveness is evaluated by comparing the "Levelized Cost of Conserved Energy (LCOCE)" of available advanced technical measures with the "Actual Cost" of conserved energy. The "Actual Cost" of energy is defined by adding the environmental externalities costs and hidden government subsidies over the retail prices of energy. The achievable potential analyses are particularly based on two key realistic factors: 1) the gradual ramping-up adoption process of advanced technical measures; and 2) individuals' adoption-decision making on them. For implementing the achievable potential analyses in Xiamen, a residential energy consumption (REC) projection model specifically tailored for southern China is developed. This computational model builds on the Kastovich (1982) adoption-decision theory and the general logic used in the U.S. EIA's (2003) National Energy Modeling System (NEMS). Base on this projection model, Xiamen's REC from the base year 2011 to 2020 is projected. This model can be used as a policy analysis tool to quantitatively evaluate the real-world impact of diverse policy incentives on residential energy use in southern China. The projection results show that the MAP of residential energy savings in Xiamen will be about only 8.3-8.4% in 2020 from a business-as-usual projection. Ten current appropriate and feasible policy interventions are evaluated for analyzing the PAP in Xiamen, which reveals that only about one-fourth to one-half of Xiamen's MAP will possibly be achieved in 2020. Based on the potential analysis for the Xiamen case, a discussion on promoting energy-saving incentive policies for the residential buildings in southern China is given. It suggests that more new, innovative and market-based policies need to be introduced in China in order to realize larger achievable potential for residential energy savings.

  13. Paleomagnetism of the Cambrian Sediments in Bornholm (Denmark) and Southern Sweden and Implications for Paleogeography of Baltica

    NASA Astrophysics Data System (ADS)

    Lewandowski, M.; Abrahamsen, N.

    2001-12-01

    In Bornholm the Phanerozoic sedimentary succession overlying Precambrian basement starts with the Lower Cambrian (ca. 545 Ma) Nekso Sandstone Fm (NSF) that, in the earlier paleomagnetic analyses, have yielded characteristic magnetization (ChRM) similar to the Permian direction for Baltica. Here, we present paleomagnetic results from other Lower Cambrian formations in Bornholm (Balka Sandstone, Broens Odde siltstone) and in southern Sweden (Hardebega, Mickwitzia and Lingula Sandstones). Lithologically, most of these formations are very similar to the NSF and they are all considered stratigraphically younger. The intention was to check, whether a Permian paleomagnetic overprint occured on a regional scale and could it be attributed to secondary magnetic phases originating from fluids, which possibly traveled laterally along the contact between the basement and the Lower Cambrian sediments. In this report we show results of this regional test, followed by a comprehensive re-analysis of our Nekso data, including new results obtained after supplementary sampling and new petrologic information, which appeared recently. We have found that the NSF possessed a unique ChRM. The well-grouped and stable characteristic magnetization of the Nekso Sandstone contrasts with fairly chaotic, soft and badly preserved magnetization of the Balka, the Hardeberga, the Mickwitzia and the Lingulid sandstones of Bornholm and southern Sweden. A regional geological context, including the inferred diagenetic evolution of Lower Cambrian sediments, points to a syndepositional/early diagenetic origin of the characteristic remanence of the Nekso Sandstone, revealing a stable remanence applicable for plate tectonic interpretations. Similarity of the characteristic remanence of the NSF to the Permian direction for Baltica has been confirmed, but it is supposed to be casual, because of lack of any sign of a regional Permian remagnetization within the other Cambrian deposits of Southern Scandinavia. This is in line with recent results from isotopic and mineralogical studies which point to a final cementation and pore closure due to the late Silurian - early Devonian burial and diagenesis, what made the sedimentary rocks in question impermeable for mineralized fluids later during the Permian time. Supportive evidence for early Cambrian age of ChRM of the NSF is detrital/early diagenetic nature of hematite, which is the main carrier of the NSF magnetization. Taking into account the relatively low (up to 150circC) temperature of the burial event, a total thermoviscous resetting of the Ti-poor hematite carriers residing in the NSF seems unrealistic in any time of its geological history. The sub-horizontal paleomagnetic inclinations obtained for the NSF indicate an equatorial position of Bornholm (and hence of Baltica ) during the time of the remanence acquisition ( paleolatitude about 8circ N or S). Possible inclination and compaction errors may only be roughly estimated (say 10circ-15circ), and this would increase the paleolatitude for the early Cambrian position of the Bornholm basin up to 15circ. Following a minimum plate velocity principle and the shortest distance between paleopoles for the APWP we propose normal polarity and the southern hemisphere for Baltica. Such a paleogeographic position and orientation of Baltica increase the drift rate for this paleocontinent in the early Cambrian-Lower Ordovician time span and makes the APWP trend more complicated than envisaged by other authors.

  14. Transpressional segment boundaries in strike-slip fault systems offshore southern California: Implications for fluid expulsion and cold seep habitats

    NASA Astrophysics Data System (ADS)

    Maloney, Jillian M.; Grupe, Benjamin M.; Pasulka, Alexis L.; Dawson, Katherine S.; Case, David H.; Frieder, Christina A.; Levin, Lisa A.; Driscoll, Neal W.

    2015-05-01

    The importance of tectonics and fluid flow in controlling cold seep habitats has long been appreciated at convergent margins but remains poorly understood in strike-slip systems. Here we present geophysical, geochemical, and biological data from an active methane seep offshore from Del Mar, California, in the inner California borderlands (ICB). The location of this seep appears controlled by localized transpression associated with a step in the San Diego Trough fault zone and provides an opportunity to examine the interplay between fluid expulsion and restraining step overs along strike-slip fault systems. These segment boundaries may have important controls on seep locations in the ICB and other margins characterized by strike-slip faulting (e.g., Greece, Sea of Marmara, and Caribbean). The strike-slip fault systems offshore southern California appear to have a limited distribution of seep sites compared to a wider distribution at convergent plate boundaries, which may influence seep habitat diversity and connectivity.

  15. Small-scale lobes in the southern hemisphere on Mars: Implications for transient liquid water in the recent past.

    NASA Astrophysics Data System (ADS)

    Johnsson, A.; Reiss, D.; Conway, S. J.; Hauber, E.; Hiesinger, H.

    2015-10-01

    We have catalogued small-scale lobes in the southern hemisphere on Mars. Small-scale lobes are restricted to crater walls and hillslopes but are morphologically distinct from viscous flow features(VFF)or other putative glacial landforms. Instead they show striking resemblance to terrestrial solifluction lobes. Previously it was shown by several authors that they are common in the northern mid and high latitudes. Here we show that they represent a hemispherical bimodal and latitude-dependent landform such as gulliesand polygonal terrain. We hypothesize that they form by freeze-thaw activity and represent geomorphologic indicators for repeated transient liquid water close to the ground surface in Mars recent climate history.

  16. Microseismicity distribution in the southern Dead Sea basin and its implications on the structure of the basin

    NASA Astrophysics Data System (ADS)

    Braeuer, B.; Asch, Guenter; Hofstetter, R.; Haberland, Ch.; Jaser, D.; El-Kelani, R.; Weber, M.

    2012-03-01

    While the Dead Sea basin has been studied for a long time, the available knowledge about the detailed seismicity distribution in the area, as well as the deeper structure of the basin, is limited. Therefore, within the framework of the international project DESIRE (DEad Sea Integrated REsearch project), a dense temporary local seismological network was operated in the southern Dead Sea area. We use 530 local earthquakes, having all together 26 730 P- and S-arrival times for a simultaneous inversion of 1-D velocity models, station corrections and precise earthquake locations. Jackknife tests suggest an accuracy of the derived hypocentre locations of about 1 km. Thus, the result is the first clear image of the absolute distribution of the microseismicity of the area, especially in depth. The seismicity is concentrated in the upper crust down to 20 km depth while the lower limit of the seismicity is reached at 31 km depth. The seismic events at the eastern boundary fault (EBF) in the southern part of the study area represent the northward transform motion of the Arabian Plate along the Dead Sea Transform. North of the Boqeq fault the seismic activity represents the transfer of the motion in the pull-apart basin from the eastern to the western boundary. We find that from the surface downward the seismic events are tracing the boundary faults of the basin. The western boundary is mapped down to 12 km depth while the EBF reaches about 17 km depth, forming an asymmetric basin. One fifth of the data set is related to a specific cluster in time and space, which occurred in 2007 February at the western border fault. This cluster is aligned vertically, that is, it is perpendicular to the direction of the dominating left-lateral strike-slip movement at the main transform fault.

  17. Peleolakes and impact basins in southern Arabia Terra, including Meridiani Planum: Implications for the formation of hematite deposits on Mars

    USGS Publications Warehouse

    Newsom, Horton E.; Barber, C.A.; Hare, T.M.; Schelble, R.T.; Sutherland, V.A.; Feldman, W.C.

    2003-01-01

    The hematite deposit in Meridiani Planum was selected for a Mars Exploration Rover (MER) landing site because water could be involved in the formation of hematite, and water is a key ingredient in the search for life. Our discovery of a chain of paleolake basins and channels along the southern margin of the hematite deposits in Meridiani Planum with the presence of the strongest hematite signature adjacent to a paleolake basin, supports the possible role of water in the formation of the hematite and the deposition of other layered materials in the region. The hematite may have formed by direct precipitation from lake water, as coatings precipitated from groundwater, or by oxidation of preexisting iron oxide minerals. The paleolake basins were fed by an extensive channel system, originating from an area larger than Texas and located south of the Schiaparelli impact basin. On the basis of stratigraphic relationships, the formation of channels in the region occurred over much of Mars' history, from before the layered materials in Meridiani Planum were deposited until recently. The location of the paleolake basins and channels is connected with the impact cratering history of the region. The earliest structure identified in this study is an ancient circular multiringed basin (800-1600 km diameter) that underlies the entire Meridiani Planum region. The MER landing site is located on the buried northern rim of a later 150 km diameter crater. This crater is partially filled with layered deposits that contained a paleolake in its southern portion. Copyright 2003 by the American Geophysical Union.

  18. Implications of water supply for indigenous Americans during Holocene ardity phases on the Southern High Plains, USA

    USGS Publications Warehouse

    Wood, W.W.; Stokes, S.; Rich, J.

    2002-01-01

    Springs in the 40 to 50 large lake basins (>15 km2) on the southern portion of the Southern High Plains (SHP) were active during periods of aridity in the Holocene when there may have been human habitation of the area. Eolian erosion of the lake floors and lunette accretion occurred as groundwater levels declined in response to decreased groundwater recharge. The declining lake floor associated with eolian erosion allowed groundwater evaporative discharge to continue, thus maintaining a groundwater gradient toward the lake. This hydrologic condition was favorable for a relatively continuous spring discharge to the lake, independent of the elevation of the lake floor. To evaluate the postulated dynamic equilibrium critical to this conclusion, 17 optically stimulated ages were determined from a 17.7-m deep core of a lunette adjacent to Double Lakes, Texas (33??13???15???N, 101??54???08???W). The core yielded sediment accumulation dates of 11,500 ?? 1100, 6500 ?? 700, and 4900 ?? 500 yr B.P., corresponding broadly with periods of aridity known from other evidence. Based on analysis of this lunette, it is concluded that springs in Double Lakes basin probably existed throughout the Holocene with discharges similar to those observed historically. We assumed that similar dynamic equilibrium existed in the other large lake basins in the SHP and that these springs could have provided a continuous source of water for indigenous peoples during periods of prolonged aridity. The dynamic equilibrium that is proposed in this study is applicable not only to other arid and semiarid geographic areas with wind-erodible material but also over different geologic times. ?? 2002 University of Washington.

  19. Determinants of persistence and tolerance of carnivores on Namibian ranches: implications for conservation on Southern African private lands.

    PubMed

    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 carnivore conservation is being attempted on private lands. PMID:23326333

  20. Historical land-use and landscape change in southern Sweden and implications for present and future biodiversity.

    PubMed

    Cui, Qiao-Yu; Gaillard, Marie-Jos; Lemdahl, Geoffrey; Stenberg, Li; Sugita, Shinya; Zernova, Ganna

    2014-09-01

    The two major aims of this study are (1) To test the performance of the Landscape Reconstruction Algorithm (LRA) to quantify past landscape changes using historical maps and related written sources, and (2) to use the LRA and map reconstructions for a better understanding of the origin of landscape diversity and the recent loss of species diversity. Southern Sweden, hemiboreal vegetation zone. The LRA was applied on pollen records from three small bogs for four time windows between AD 1700 and 2010. The LRA estimates of % cover for woodland/forest, grassland, wetland, and cultivated land were compared with those extracted from historical maps within 3-km radius around each bog. Map-extracted land-use categories and pollen-based LRA estimates (in % cover) of the same land-use categories show a reasonable agreement in several cases; when they do not agree, the assumptions used in the data (maps)-model (LRA) comparison are a better explanation of the discrepancies between the two than possible biases of the LRA modeling approach. Both the LRA reconstructions and the historical maps reveal between-site differences in landscape characteristics through time, but they demonstrate comparable, profound transformations of the regional and local landscapes over time and space due to the agrarian reforms in southern Sweden during the 18th and 19th centuries. The LRA was found to be the most reasonable approach so far to reconstruct quantitatively past landscape changes from fossil pollen data. The existing landscape diversity in the region at the beginning of the 18th century had its origin in the long-term regional and local vegetation and land-use history over millennia. Agrarian reforms since the 18th century resulted in a dramatic loss of landscape diversity and evenness in both time and space over the last two centuries leading to a similarly dramatic loss of species (e.g., beetles). PMID:25478148

  1. Tectonic magnetic lineation and oroclinal bending of the Alborz range: Implications on the Iran-Southern Caspian geodynamics

    NASA Astrophysics Data System (ADS)

    Cifelli, Francesca; Ballato, Paolo; Alimohammadian, Habib; Sabouri, Jafar; Mattei, Massimo

    2015-01-01

    In this study we use the anisotropy of magnetic susceptibility (AMS) and paleomagnetic data for deciphering the origin of magnetic lineation in weakly deformed sedimentary rocks and for evaluating oroclinal processes within the Arabia-Eurasia collision zone. In particular, we have analyzed the Miocene Upper Red Formation (URF) from the outer curved front of the southern Central Alborz Mountains of north Iran, to test for the first time with paleomagnetic data the origin (primary versus secondary) of this orogenic arc. AMS data document the existence of a magnetic lineation parallel to the orientation of the major tectonic structures, which vary along strike from WNW to ENE. These directions are highly oblique to the paleoflow directions and hence suggest that the magnetic lineation in the URF was produced by compressional deformation during layer-parallel shortening. In addition, our paleomagnetic data document clockwise and anticlockwise rotations along vertical axis for the western and eastern sectors of the Central Alborz Mountains, respectively. Combined, our results suggest that the orogen represents an orocline, which formed not earlier than circa 7.6 Ma most likely through bending processes caused by the relative motion between the rigid crustal blocks of the collision zone. Moreover, our study provides new insights into the Iran-Southern Caspian Basin kinematic evolution suggesting that the present-day SW motion of the South Caspian Basin with respect to Central Iran postdates oroclinal bending and hence cannot be as old as late Miocene to early Pliocene but a rather recent configuration (i.e., 3 to <1 Ma).

  2. Historical land-use and landscape change in southern Sweden and implications for present and future biodiversity

    PubMed Central

    Cui, Qiao-Yu; Gaillard, Marie-José; Lemdahl, Geoffrey; Stenberg, Li; Sugita, Shinya; Zernova, Ganna

    2014-01-01

    The two major aims of this study are (1) To test the performance of the Landscape Reconstruction Algorithm (LRA) to quantify past landscape changes using historical maps and related written sources, and (2) to use the LRA and map reconstructions for a better understanding of the origin of landscape diversity and the recent loss of species diversity. Southern Sweden, hemiboreal vegetation zone. The LRA was applied on pollen records from three small bogs for four time windows between AD 1700 and 2010. The LRA estimates of % cover for woodland/forest, grassland, wetland, and cultivated land were compared with those extracted from historical maps within 3-km radius around each bog. Map-extracted land-use categories and pollen-based LRA estimates (in % cover) of the same land-use categories show a reasonable agreement in several cases; when they do not agree, the assumptions used in the data (maps)-model (LRA) comparison are a better explanation of the discrepancies between the two than possible biases of the LRA modeling approach. Both the LRA reconstructions and the historical maps reveal between-site differences in landscape characteristics through time, but they demonstrate comparable, profound transformations of the regional and local landscapes over time and space due to the agrarian reforms in southern Sweden during the 18th and 19th centuries. The LRA was found to be the most reasonable approach so far to reconstruct quantitatively past landscape changes from fossil pollen data. The existing landscape diversity in the region at the beginning of the 18th century had its origin in the long-term regional and local vegetation and land-use history over millennia. Agrarian reforms since the 18th century resulted in a dramatic loss of landscape diversity and evenness in both time and space over the last two centuries leading to a similarly dramatic loss of species (e.g., beetles). PMID:25478148

  3. Determinants of Persistence and Tolerance of Carnivores on Namibian Ranches: Implications for Conservation on Southern African Private Lands

    PubMed Central

    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 carnivore conservation is being attempted on private lands. PMID:23326333

  4. Increased dry-season length over southern Amazonia in recent decades and its implication for future climate projection

    PubMed Central

    Fu, Rong; Yin, Lei; Li, Wenhong; Arias, Paola A.; Dickinson, Robert E.; Huang, Lei; Chakraborty, Sudip; Fernandes, Katia; Liebmann, Brant; Fisher, Rosie; Myneni, Ranga B.

    2013-01-01

    We have observed that the dry-season length (DSL) has increased over southern Amazonia since 1979, primarily owing to a delay of its ending dates (dry-season end, DSE), and is accompanied by a prolonged fire season. A poleward shift of the subtropical jet over South America and an increase of local convective inhibition energy in austral winter (June–August) seem to cause the delay of the DSE in austral spring (September–November). These changes cannot be simply linked to the variability of the tropical Pacific and Atlantic Oceans. Although they show some resemblance to the effects of anthropogenic forcings reported in the literature, we cannot attribute them to this cause because of inadequate representation of these processes in the global climate models that were presented in the Intergovernmental Panel on Climate Change’s Fifth Assessment Report. These models significantly underestimate the variability of the DSE and DSL and their controlling processes. Such biases imply that the future change of the DSE and DSL may be underestimated by the climate projections provided by the Intergovernmental Panel on Climate Change’s Fifth Assessment Report models. Although it is not clear whether the observed increase of the DSL will continue in the future, were it to continue at half the rate of that observed, the long DSL and fire season that contributed to the 2005 drought would become the new norm by the late 21st century. The large uncertainty shown in this study highlights the need for a focused effort to better understand and simulate these changes over southern Amazonia. PMID:24145443

  5. Increased dry-season length over southern Amazonia in recent decades and its implication for future climate projection.

    PubMed

    Fu, Rong; Yin, Lei; Li, Wenhong; Arias, Paola A; Dickinson, Robert E; Huang, Lei; Chakraborty, Sudip; Fernandes, Katia; Liebmann, Brant; Fisher, Rosie; Myneni, Ranga B

    2013-11-01

    We have observed that the dry-season length (DSL) has increased over southern Amazonia since 1979, primarily owing to a delay of its ending dates (dry-season end, DSE), and is accompanied by a prolonged fire season. A poleward shift of the subtropical jet over South America and an increase of local convective inhibition energy in austral winter (June-August) seem to cause the delay of the DSE in austral spring (September-November). These changes cannot be simply linked to the variability of the tropical Pacific and Atlantic Oceans. Although they show some resemblance to the effects of anthropogenic forcings reported in the literature, we cannot attribute them to this cause because of inadequate representation of these processes in the global climate models that were presented in the Intergovernmental Panel on Climate Change's Fifth Assessment Report. These models significantly underestimate the variability of the DSE and DSL and their controlling processes. Such biases imply that the future change of the DSE and DSL may be underestimated by the climate projections provided by the Intergovernmental Panel on Climate Change's Fifth Assessment Report models. Although it is not clear whether the observed increase of the DSL will continue in the future, were it to continue at half the rate of that observed, the long DSL and fire season that contributed to the 2005 drought would become the new norm by the late 21st century. The large uncertainty shown in this study highlights the need for a focused effort to better understand and simulate these changes over southern Amazonia. PMID:24145443

  6. N Isotopes in Nile Sediments (ethiopia, Sudan)

    NASA Astrophysics Data System (ADS)

    Padoan, M.; Villa, I. M.; Garzanti, E.; Galbusera, M.; Quistini, S.; Peruta, L.; El Kammar, A.

    2009-04-01

    The Nile is the most important river of the Eastern Mediterranean. Its water and sediment fluxes have greatly influenced marine circulation throughout the Quaternary, and are widely considered as possible causes for stagnation and formation of sapropel (Krom et al., 1999a; 2002; Talbot et al., 2000; Freydier et al., 2001; Weldeab et al., 2002; Scrivner et al., 2004). Variations in annual flooding and baseflow of the river Nile, controlled by climate changes, had major impact on the rise and demise of Egyptian dynasties (Stanley et al., 2003). In order to better define sedimentary sources of the Nile system and to obtain more robust results, we have analyzed Nd isotopes in sediments of all its major Sudanese and Ethiopian tributaries (Atbara, Gash, Abay, Didesa, Dabus, White Nile, Bahr Ez Zeraf) in several replicate samples. Analyses were carried out on distinct mud and sand fractions (<40 microns and 125-180 microns) of 30 samples, and systematic changes related to grain size and hydraulic-sorting processes could thus be investigated. On the same samples, companion studies are being carried out on Sr isotopes (Padoan et al., 2007) and on Pb isotopes at the Geological Survey of Israel (Harlavan et al., in preparation). Overall, isotopic signals are markedly different between the White Nile system, derived from largely Archean to Paleoproterozoic basement rocks, and Ethiopian tributaries, derived in diverse proportions from largely Neoproterozoic rift-shoulder basements and overlying Oligocene flood basalts. Isotopic signals of Main Nile sediments downstream of the Atbara confluence are close to those of Blue Nile sediments, indicating that detritus is mainly provided by the latter (Garzanti et al., 2006). In the White Nile branch, the 143Nd/144Nd ratio of the mud fraction is lower in the Bahr Ez Zeraf (0.51167) than in the White Nile downstrean of the Sobat confluence (0.51219), revealing significant sediment influx from the latter. In Blue Nile and Atbara branches, values vary from 0.51240-0.51242 for tributaries draining basement rocks only (e.g., Gash, wadi Guba) to 0.51275-0.51280 for tributaries draining mostly basaltic rocks (Atbara); tributaries draining both record mixed signals (e.g., 0.51259; Beles). Nd ratios for Atbara sediments correspond closely with signatures of volcanic source rocks (0.51271-0.51298; Pik et al., 1999), revealing involvement of various mantle and crustal components in petrogenesis of flood basalts. Corresponding Nd model ages (tDM) cluster around 0.84 Ga for the mostly volcanic-derived Blue Nile, Atbara, and Main Nile muds, range 1.2 - 1.5 Ga for tributaries draining Ethiopian basement rocks, and reach as high as 2.4 Ga for the Bahr Ez Zeraf. The different Nd isotopic signal between mud and sand samples is closely controlled by mineralogical composition, Nd and other REE being chiefly contributed by ultradense minerals (e.g., monazite), and consequently concentrated in the finest size fractions of each sample (Garzanti et al., 2008). FREYDIER, R., MICHARD, A., DE LANGE G., THOMSON, J., 2001. Nd isotopic composition of Eastern Mediterranean sediments: tracers of the Nile influence during sapropel S1 formation. Mar. Geol., 177, 45-62. GARZANTI, E., ANDÒ, S., VEZZOLI, G., ABDEL MEGID, A.A., EL KAMMAR, A., 2006. Petrology of Nile River sands (Ethiopian and Sudan): Sediment budgets and erosion patterns. Earth Planet. Sci. Lett., 252, 327-341. GARZANTI, E., ANDÒ, S., VEZZOLI, G., 2008. Settling-equivalence of detrital minerals and grain-size dependence of sediment composition. Earth Planet. Sci. Lett. 273, 138-151. HARLAVAN Y., GARZANTI, E., PADOAN, M., EL KAMMAR, A. Geochemical characterization of Nile River sands; Rare earth elements, Pb and Sr isotopes of the fine fraction. In preparation. KROM, M.D., CLIFF, R.A., EIJSINK, L.M., HERUT, B., CHESTER, R., 1999a. The characterisation of Saharan dusts and Nile particulate matter in surface sediments from the Levantine basin using Sr isotopes. Mar. Geol., 155, 319-330. KROM, M.D., STANLEY, J.D., CLIFF, R.A., WOODWARD, J.C., 2002. Nile River sediment fluctuations over the past 7000 yr and their key role in sapropel development. Geol., 30, n. 1, 71-74. PADOAN M., GALBUSERA M., QUISTINI S., VILLA I.M., AND GARZANTI E., 2007 Isotopic tracers of Nile sediment sources. AGU Fall Meeting, San Francisco December 2007. PIK, R., DENIEL, C., COULON, C., YIRGU, G., MARTY, B., 1999, Isotopic and trace element signatures of Ethiopian flood basalts: Evidence for plume-lithosphere interactions. Geochim. Cosmochim. Acta, 63, 2263-2279. SCRIVNER, A., VANCE, D., ROHLING, E.J., 2004. New neodymium isotope data quantify Nile involvement in Mediterranean anoxic episodes. Geol., 32, n. 7, 565-568. STANLEY, J.D., KROM, M.D., CLIFF, R.A., WOODWARD, J.C., 2003. Short Contribution: Nile flow failure at the End of the Old Kingdom, Egypt: strontium isotopic and petrologic evidence. TALBOT, M.R., WILLIAMS, M.A.J., ADAMSON, D.A., 2000. Strontium isotope evidence for late Pleistocene reestablishment of an integrated Nile drainage network. Geol., 28, n. 4, 343-346. WELDEAB, S., EMEIS, K.C., HEMLEBEN, C., SIEBEL, W., 2002. Provenance of lithogenic surface sediments and pathway of riverine suspended matter in the Eastern Mediterranean Sea: evidence from 143Nd/144Nd and 87Sr/86Sr ratios. Chem. Geol., 186, 139-149.

  7. Multi-decadal variability and trends in the El Niño-Southern Oscillation and tropical Pacific fisheries implications

    NASA Astrophysics Data System (ADS)

    Harrison, D. E.; Chiodi, Andrew M.

    2015-03-01

    Extremes of the El Niño-Southern Oscillation (ENSO) are known to have various socio-economic impacts, including effects on several Pacific fisheries. The 137-year-long record of Darwin sea-level pressure offers a uniquely long-term perspective on ENSO and provides important insight into various aspects of interannual to century-scale variability that affects these fisheries. One particular issue of interest is whether there is a centennial-scale (or longer) trend that can be expected to alter the future distributions of these fisheries. Since most tropical Pacific fishery records are no longer than a few decades, another issue is the extent to which trends over these recent decades are a good basis for detecting the presence of long-term (e.g., centennial-scale) deterministic changes, and perhaps thereby projecting future conditions. We find that the full 137-yr trend cannot be distinguished from zero with 95% confidence, and also that the ENSO variance in recent decades is very similar to that of the early decades of the record, suggesting that ENSO has not fundamentally changed over the period of large increase in atmospheric CO2. However, the strong multi-decadal variability in ENSO is reflected in decades with quite different levels of ENSO effects on the ecosystem. Many multi-decadal subsets of the full record have statistically significant trends, using standard analysis techniques. These multi-decadal trends are not; however, representative of the record-length trend, nor are they a useful basis for projecting conditions in subsequent decades. Trend statistical significance is not a robust foundation for speculation about the future. We illustrate how the difficulties involved in determining whether a trend is statistically significant or not mean that, even after careful consideration, an unexpectedly large number of trends may reach standard statistical significance levels over the time spans for which many newer records are available, but still not continue into future decades or be indicative of deterministic changes to the system. Analysis of the Southern Oscillation Index, another common ENSO index, but one that has been directly measured for fewer years than has Darwin, yields similar results.

  8. Regional variations in the lead isotopic composition of galena from southern Korea with implications for the discrimination of lead provenance

    NASA Astrophysics Data System (ADS)

    Jeong, Youn-Joong; Cheong, Chang-sik; Shin, Dongbok; Lee, Kwang-Sik; Jo, Hui Je; Gautam, Mukesh Kumar; Lee, Insung

    2012-11-01

    This study presents a comprehensive database (n = 215) of lead isotopes in galena from the southern Korean peninsula using new and published data. Of the 69 metal mines examined, predominantly skarn- and hydrothermal-type Pb-Zn-Au-Ag-Cu deposits were observed and were associated with Mesozoic magmatic activities. Galena samples from each geotectonic unit showed discrete lead isotopic signatures. The Gyeongsang basin samples were characteristically unradiogenic and had restricted variations in lead isotopic composition (206Pb/204Pb = 18.16-18.59, 207Pb/204Pb = 15.48-15.64, 208Pb/204Pb = 37.87-38.77). Their 208Pb/204Pb range indicated an involvement of source materials less thorogenic than the associated granites. The galena samples from Cambro-Ordovician carbonate rocks of the northeastern Yeongnam massif and eastern Taebaeksan basin had the most radiogenic 206Pb/204Pb (19.28 ± 0.14) and 207Pb/204Pb (15.833 ± 0.027) ratios. Their lead isotopic trend indicated a combined contribution of ore lead from granitic magmas, Precambrian basements, and overlain host rocks. Less radiogenic galena samples from the middle to southwestern parts of the Yeongnam massif and Okcheon belt showed limited lead isotopic variations (206Pb/204Pb = 18.332 ± 0.065, 207Pb/204Pb = 15.693 ± 0.012, 208Pb/204Pb = 38.93 ± 0.07 on average), probably resulted from mixing with a common crustal basement. The differences in lead isotopes between the radiogenic and unradiogenic groups from the Yeongnam massif and Okcheon belt may reflect the spatial dissimilarity of involved crustal rocks. The old crust appears to have significantly contributed ore lead to galenas from the western Gyeonggi massif, but the geochronological meaning of their steep 207Pb/204Pb-206Pb/204Pb trend is not clear. The comprehensive database constructed by the present study suggests that lead province in the southern Korean peninsula may be subdivided into four discrete zones. Linear discriminant analysis showed that more than 90% of the compiled data were correctly reclassified within their a priori zones. Such discrimination may be useful for a wide range of applications, including mineral exploration, archaeological correlation, and environmental characterization.

  9. Focal mechanisms in the Southern Aegean from temporary seismic networks - implications for the regional stress field and ongoing deformation processes

    NASA Astrophysics Data System (ADS)

    Friederich, W.; Brstle, A.; Kperkoch, L.; Meier, T.

    2013-10-01

    The lateral variation of the stress field in the southern Aegean plate and the subducting Hellenic slab is determined from recordings of seismicity obtained with the CYCNET and EGELADOS networks in the years from 2002 to 2007. First motions from 7000 well-located earthquakes were analysed to produce 540 well-constrained focal mechanisms. They were complemented by another 140 derived by waveform matching of records from larger events. Most of these earthquakes fall into 16 distinct spatial clusters distributed over the southern Aegean region. For each cluster, a stress inversion could be carried out yielding consistent estimates of the stress field and its spatial variation. At crustal levels, the stress field is generally dominated by a steeply dipping compressional principal stress direction except in places where coupling of the subducting slab and overlying plate come into play. Tensional principal stresses are generally subhorizontal. Just behind the forearc, the crust is under arc-parallel tension whereas in the volcanic areas around Kos, Columbo and Astypalea tensional and intermediate stresses are nearly degenerate. Further west and north, in the Santorini-Amorgos graben and in the area of the islands of Mykonos, Andros and Tinos, tensional stresses are significant and point around the NW-SE direction. Very similar stress fields are observed in western Turkey with the tensional axis rotated to NNE-SSW. Intermediate depth earthquakes below 100 km in the Nisyros region indicate that the Hellenic slab experiences slab-parallel tension at these depths. The direction of tension is close to east-west and thus deviates from the local NW-oriented slab dip presumably owing to the segmentation of the slab. Beneath the Cretan sea, at shallower levels, the slab is under NW-SE compression. The lateral and depth variations of the stress field reflect the various agents that influence tectonics in the Aegean: subduction of the Hellenic slab, incipient collision with continental African lithosphere, roll back of the slab in the south-east, segmentation of the slab, arc volcanism and extension of the Aegean crust.

  10. Volatile organic compounds from vegetation in southern Yunnan Province, China: Emission rates and some potential regional implications

    NASA Astrophysics Data System (ADS)

    Geron, Chris; Owen, Sue; Guenther, Alex; Greenberg, Jim; Rasmussen, Rei; Hui Bai, Jian; Li, Qing-Jun; Baker, Brad

    Little information is currently available regarding emissions of biogenic volatile organic compounds (BVOCs) in southern Asia. To address the need for BVOC emission estimates in regional atmospheric chemistry simulations, 95 common plant species were screened for emissions of BVOC in and near the Xishuangbanna Tropical Biological Gardens in southern Yunnan Province, Peoples' Republic of China in February 2003. In situ measurements with leaf cuvettes and branch bag enclosures were used in combination with portable gas chromatography, flame ionization, photoionization, and mass spectral detection to identify and quantify BVOC emissions. Forty-four of the species examined emitted isoprene at rates exceeding 20 μg C g -1 (leaf dry weight) h -1. An emphasis was placed on the genus Ficus, which is important in the region and occupies a wide range of ecological niches. Several species in the footprint of a nearby flux tower were also examined. Several palm species and an abundant fern ( Cyclosorus parasiticus) emitted substantial amounts of isoprene, and probably accounted for observed daytime mean isoprene fluxes from the understory of a Hevea brasiliensis plantation of 1.0 and 0.15 mg C m -2 h -1 during the wet and dry seasons, respectively. These measurements verify that both the forest floor and canopy in this region can be sources of isoprene. Monoterpene emissions exceeded 1.0 μg-C g -1 (leaf dry weight) h -1 from only 4 of 38 species surveyed, including some Ficus species and H. brasiliensis. However most of the trees of the latter species were sparsely foliated due to dry season senescence, and emission factors are approximately an order of magnitude lower than those reported during the wet season. BVOC emission rates and physiology of many species are impacted by reduced moisture availability, especially Mangifera indica. South Asia is a region undergoing rapid landuse change and forest plantation establishment, with large increases in area of high BVOC-emitting species in the genera Bambusa, Elaeis, Eucalyptus, Hevea, Pinus, and Populus (among others). This could result in profound changes in atmospheric chemistry in these regions, for instance, terpene emissions from H. brasiliensis could increase wet season biogenic organic aerosol burdens by approximately a factor of 2 in the Xishuangbanna region. Increases in plantation area established with high isoprene emitting species, (e.g. Bambusa spp. and Eucalyptus spp.) are also projected for China and other parts of Southeast Asia in the near future. Thus, landcover change in South Asian landscapes is usually associated with large increases in BVOC flux with the potential to alter the atmospheric chemical composition and air quality over this rapidly developing region.

  11. ELEMENTAL UPTAKE BY SORGHUM SUDAN GRASS FROM A FLUE GAS DESULPHURIZATION WASTE AMENDED SOIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A greenhouse study was conducted to assess the effect of flue gas desulphurization (FGDW) waste on elemental uptake by sorghum sudan grass (Sorghum sundensis L.). Unweathered FGDW was applied to an Ogeechee loamy soil (Typic Paleudult) at 1, 2, 3, 4, 5, and 6% by weight. The sorghum-sudan grass was ...

  12. Games, Social Simulations, and Data--Integration for Policy Decisions: The "Sudan" Game

    ERIC Educational Resources Information Center

    Landwehr, Peter; Spraragen, Marc; Ranganathan, Balki; Carley, Kathleen M.; Zyda, Michael

    2013-01-01

    In this article, the authors discuss the development of the "Sudan Game," an interactive model of the country in the time period leading up to the Sudanese referendum on the secession of the South. While many simulations are designed to educate about their subjects, the "Sudan Game" is intended to be a prototype for policy making via gameplay. It…

  13. Games, Social Simulations, and Data--Integration for Policy Decisions: The "Sudan" Game

    ERIC Educational Resources Information Center

    Landwehr, Peter; Spraragen, Marc; Ranganathan, Balki; Carley, Kathleen M.; Zyda, Michael

    2013-01-01

    In this article, the authors discuss the development of the "Sudan Game," an interactive model of the country in the time period leading up to the Sudanese referendum on the secession of the South. While many simulations are designed to educate about their subjects, the "Sudan Game" is intended to be a prototype for policy making via gameplay. It

  14. 3 CFR - Certification Concerning U.S. Participation in the United Nations Mission in South Sudan...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... United Nations Mission in South Sudan Consistent With Section 2005 of the American Servicemembers... Certification Concerning U.S. Participation in the United Nations Mission in South Sudan Consistent With Section... in certain United Nations peacekeeping and peace enforcement operations, I hereby certify...

  15. Overcoming Structural Adjustment Policies in Africa: Strategies for Vocational Education and Training in the Sudan.

    ERIC Educational Resources Information Center

    Washi, Sidiga; Pitamber, Sunita

    Most developing countries have been debt ridden since the mid-1970s. This continuing debt burden has resulted in increasing prices and inflation, growing unemployment, and daily life difficulties. This problem has been acute for the Sudan. Sudan received help from the International Monetary Fund (IMF) in 1978 and negotiated new credit terms. By…

  16. Upconversion nanosensor for sensitive fluorescence detection of Sudan I-IV based on inner filter effect.

    PubMed

    Fang, Aijin; Long, Qian; Wu, Qiongqiong; Li, Haitao; Zhang, Youyu; Yao, Shouzhuo

    2016-02-01

    Sudan dyes are banned as food additives due to the carcinogenicity of their metabolites in the human body. Therefore, it is of great significance for sensitive detection of Sudan dyes. This paper reports a novel nanosensor for Sudan dyes detection based on fluorescence (FL) quenching of hexadecyl trimethyl ammonium bromide (CTAB) stabilized upconversion nanoparticles (UCNPs) through the inner filter effect (IFE). In the presence of Sudan I-IV, the fluorescence emission of UCNPs was effectively quenched due to the absorption bands of Sudan I-IV largely covered the emission bands of UCNPs. Under the optimized conditions, the FL was quenched with Sudan concentration over the range of 0.05-40, 0.01-20, 0.01-40 and 0.05-40 μg/mL for Sudan I-IV, respectively. The corresponding limit of detection is 15.1, 2.83, 3.52 and 16.7 ng/mL (at 3σ/slope) respectively. Meanwhile, the nanosensor shows good selectivity, sensitivity and can be successfully applied to detection of Sudan in chili powder samples. PMID:26653433

  17. The Birth of a Nation Is Only the Beginning: The Travails of South Sudan

    ERIC Educational Resources Information Center

    Totten, Samuel

    2014-01-01

    Just three years since it broke away from Sudan, the new country of South Sudan is embroiled in a violent civil war. This article examines what went wrong and why, by discussing the incredible difficulty of building a new nation from scratch following years of conflict, war, suspicion, and great expectations. How this tragedy will end is…

  18. The Lost Boys of Sudan: Ambiguous Loss, Search for Family, and Reestablishing Relationships with Family Members

    ERIC Educational Resources Information Center

    Luster, Tom; Qin, Desiree B.; Bates, Laura; Johnson, Deborah J.; Rana, Meenal

    2008-01-01

    The "Lost Boys of Sudan" were separated from their families by civil war and subsequently lived in 3 other countries--Ethiopia, Kenya, and the United States. In-depth interviews were conducted with 10 refugees who located surviving family members in Sudan after an average separation of 13.7 years. The interviews probed their experiences of…

  19. Last glacial-interglacial environments in the southern Rocky Mountains, USA and implications for Younger Dryas-age human occupation

    NASA Astrophysics Data System (ADS)

    Briles, Christy E.; Whitlock, Cathy; Meltzer, David J.

    2012-01-01

    The last glacial-interglacial transition (LGIT; 19-9 ka) was characterized by rapid climate changes and significant ecosystem reorganizations worldwide. In western Colorado, one of the coldest locations in the continental US today, mountain environments during the late-glacial period are poorly known. Yet, archaeological evidence from the Mountaineer site (2625 m elev.) indicates that Folsom-age Paleoindians were over-wintering in the Gunnison Basin during the Younger Dryas Chronozone (YDC; 12.9-11.7 ka). To determine the vegetation and fire history during the LGIT, and possible explanations for occupation during a period thought to be harsher than today, a 17-ka-old sediment core from Lily Pond (3208 m elev.) was analyzed for pollen and charcoal and compared with other high-resolution records from the southern Rocky Mountains. Widespread tundra and Picea parkland and low fire activity in the cold wet late-glacial period transitioned to open subalpine forest and increased fire activity in the Bølling-Allerød period as conditions became warmer and drier. During the YDC, greater winter snowpack than today and prolonged wet springs likely expanded subalpine forest to lower elevations than today, providing construction material and fuel for the early inhabitants. In the early to middle Holocene, arid conditions resulted in xerophytic vegetation and frequent fire.

  20. Presence of Zea luxurians (Durieu and Ascherson) Bird in Southern Brazil: Implications for the Conservation of Wild Relatives of Maize.

    PubMed

    Silva, Natália Carolina de Almeida; Vidal, Rafael; Costa, Flaviane Malaquias; Vaio, Magdalena; Ogliari, Juliana Bernardi

    2015-01-01

    Records of the occurrence of wild relatives of maize in South American lowlands are unprecedented, especially in sympatric coexistence with landraces. This fact is relevant, because regions of occurrence of wild relatives of cultivated plants should be a priority for conservation, even if they do not correspond to the center of origin of the species. The aim of this study was to identify and characterize the wild relatives of maize in the Far West of Santa Catarina, southern Brazil. Therefore, phenotypic characterization was performed for five populations, based on 22 morphological traits deemed as fundamental for classifying the species of the genus Zea, and validated through the characterization of chromosomal knobs of two populations. The occurrence and distribution of teosinte populations were described through semi-structured interviews applied to a sample of 305 farmers. A total of 136 teosinte populations were identified; 75% of them occur spontaneously, 17% are cultivated populations, and 8% occur both ways, for the same farm. Populations that were characterized morphologically had trapezoidal fruits mostly, upright tassel branch (4-18), non-prominent main branch and glabrous glumes, with two protruding outer ribs and 8 inner ribs, on average. Cytogenetic analysis identified 10 pairs of homologous chromosomes (2n = 20) with 26 knobs, located in the terminal region of all chromosomes. The similarity of these results with the information reported in the literature indicates that the five populations of wild relatives of maize in this region of Santa Catarina belong to the botanical species Zea luxurians. PMID:26488577

  1. Interaction of ambient conditions and fecal coliform bacteria in southern Lake Michigan beach waters: Monitoring program implications

    USGS Publications Warehouse

    Whitman, Richard L.; Nevers, Meredith Becker; Gerovac, Paul J.

    1999-01-01

    Excessive fecal coliform bacteria in public swimming waters can potentially threaten visitor health. Fecal coliform bacteria (1984-1989) and Escherichia coli (1990-1995) density were monitored weekly at the Indiana Dunes National Lakeshore beaches for 12 summers, and park officials closed swimming areas when fecal coliform density exceeded the state water quality criteria (400 CFU fecal coliforms/ 100 ml; 235 CFU E. coli/100 ml water). Due to a 24-hour incubation in the fecal coliform and E. coli assays, beaches were closed the day after collection of high fecal coliform. Our analysis suggests that it is not possible to predict one day's fecal coliform count based on the previous day's results in waters taken from southern Lake Michigan beaches. Dispersal and deposition of bacteria were not uniform among sites or across time apparently due to interactions among environmental variables including rainfall, wind direction, water temperature, and bacteria source. Rainfall combined with northwest winds increased bacteria concentrations. Escherichia coli followed a seasonal trend with similar fluctuations in density among beaches. We suggest that the current beach monitoring protocol is inadequate for predicting fecal coliform density at the time of beach closure, and, subsequently, its use for ensuring visitor safety remains questionable.

  2. Recent and old groundwater in the Niebla-Posadas regional aquifer (southern Spain): Implications for its management

    NASA Astrophysics Data System (ADS)

    Scheiber, Laura; Ayora, Carlos; Vázquez-Suñé, Enric; Cendón, Dioni I.; Soler, Albert; Custodio, Emilio; Baquero, Juan Carlos

    2015-04-01

    The Niebla-Posadas (NP) aquifer in southern Spain is one of the main groundwater sources for the lower Guadalquivir Valley, a semiarid region supporting an important population, agriculture and industry. To contribute to the understanding of this aquifer the assessment of sustainable use of groundwater, the residence time of groundwater in the NP aquifer has been estimated using 3H, 14C and 36Cl. Along the flow paths, recharged groundwater mixes with NaCl-type waters and undergoes calcite dissolution and is further modified by cation exchange (Ca-Na). Consequently, the water loses most of its calcium and the residual δ13CDIC in the groundwater is isotopically enriched. Further modifications take place along the flow path in deeper zones, where depleted δ13CDIC values are overprinted due to SO42- and iron oxide reduction, triggered by the presence of organic matter. Dating with 3H, 14C and 36Cl has allowed the differentiation of several zones: recharge zone (<0.06 ky), intermediate zone (0.06-20 ky), deep zone 1 (20-30 ky), and deep zone 2 (>30 ky). An apparent link between the tectonic structure and the groundwater residence time zonation can be established. Regional faults clearly separates deep zone 1 from the distinctly older age (>30 ky) deep zone 2. From the estimated residence times, two groundwater areas of different behavior can be differentiated within the aquifer.

  3. A New Oviraptorid Dinosaur (Dinosauria: Oviraptorosauria) from the Late Cretaceous of Southern China and Its Paleobiogeographical Implications.

    PubMed

    Lü, Junchang; Pu, Hanyong; Kobayashi, Yoshitsugu; Xu, Li; Chang, Huali; Shang, Yuhua; Liu, Di; Lee, Yuong-Nam; Kundrát, Martin; Shen, Caizhi

    2015-01-01

    The Ganzhou area of Jiangxi Province, southern China is becoming one of the most productive oviraptorosaurian localities in the world. A new oviraptorid dinosaur was unearthed from the uppermost Upper Cretaceous Nanxiong Formation of Ganzhou area. It is characterized by an anterodorsally sloping occiput and quadrate (a feature shared with Citipati), a circular supratemporal fenestra that is much smaller than the lower temporal fenestra, and a dentary in which the dorsal margin above the external mandibular fenestra is strongly concave ventrally. The position of the anteroventral corner of the external naris in relation to the posterodorsal corner of the antorbital fenestra provides new insight into the craniofacial evolution of oviraptorosaurid dinosaurs. A phylogenetic analysis recovers the new taxon as closely related to the Mongolian Citipati. Six oviraptorid dinosaurs from the Nanxiong Formation (Ganzhou and Nanxiong) are distributed within three clades of the family. Each of the three clades from the Nanxiong Formation has close relatives in Inner Mongolia and Mongolia, and in both places each clade may have had a specific diet or occupied a different ecological niche. Oviraptorid dinosaurs were geographically widespread across Asia in the latest Cretaceous and were an important component of terrestrial ecosystems during this time. PMID:26133245

  4. Inorganic contaminants from diffuse pollution in shallow groundwater of the Campanian Plain (Southern Italy). Implications for geochemical survey.

    PubMed

    Cuoco, E; Darrah, T H; Buono, G; Verrengia, G; De Francesco, S; Eymold, W K; Tedesco, D

    2015-02-01

    The Campanian Plain (CP) shallow aquifer (Southern Italy) represents a natural laboratory to validate geochemical methods for differentiating diffuse anthropogenic pollution from natural water-rock interaction processes. The CP is an appropriate study area because of numerous potential anthropogenic pollution vectors including agriculture, animal husbandry, septic/drainage sewage systems, and industry. In order to evaluate the potential for geochemical methods to differentiate various contamination vectors, 538 groundwater wells from the shallow aquifer in Campanian Plain (CP) were sampled. The dataset includes both major and trace elements. Natural water-rock interactions, which primarily depend on local lithology, control the majority of geochemical parameters, including most of the major and trace elements. Using prospective statistical methods in combination with the traditional geochemical techniques, we determined the chemical variables that are enriched by anthropogenic contamination (i.e. NO3, SO4 and U) by using NO3 as the diagnostic variable for detecting polluted groundwater. Synthetic agricultural fertilizers are responsible for the majority of SO4 and U pollution throughout the CP area. Both SO4 and U are present in the groundmass of synthetic fertilizers; the uranium concentration is specifically applicable as a tracer for non-point source agricultural fertilizer contamination. The recognition of non-geological (anthropogenic) inputs of these elements has to be considered in the geochemical investigations of contaminated aquifers. PMID:25638062

  5. A New Oviraptorid Dinosaur (Dinosauria: Oviraptorosauria) from the Late Cretaceous of Southern China and Its Paleobiogeographical Implications

    PubMed Central

    Lü, Junchang; Pu, Hanyong; Kobayashi, Yoshitsugu; Xu, Li; Chang, Huali; Shang, Yuhua; Liu, Di; Lee, Yuong-Nam; Kundrát, Martin; Shen, Caizhi

    2015-01-01

    The Ganzhou area of Jiangxi Province, southern China is becoming one of the most productive oviraptorosaurian localities in the world. A new oviraptorid dinosaur was unearthed from the uppermost Upper Cretaceous Nanxiong Formation of Ganzhou area. It is characterized by an anterodorsally sloping occiput and quadrate (a feature shared with Citipati), a circular supratemporal fenestra that is much smaller than the lower temporal fenestra, and a dentary in which the dorsal margin above the external mandibular fenestra is strongly concave ventrally. The position of the anteroventral corner of the external naris in relation to the posterodorsal corner of the antorbital fenestra provides new insight into the craniofacial evolution of oviraptorosaurid dinosaurs. A phylogenetic analysis recovers the new taxon as closely related to the Mongolian Citipati. Six oviraptorid dinosaurs from the Nanxiong Formation (Ganzhou and Nanxiong) are distributed within three clades of the family. Each of the three clades from the Nanxiong Formation has close relatives in Inner Mongolia and Mongolia, and in both places each clade may have had a specific diet or occupied a different ecological niche. Oviraptorid dinosaurs were geographically widespread across Asia in the latest Cretaceous and were an important component of terrestrial ecosystems during this time. PMID:26133245

  6. Evidence for Alleghenian brine migration in the central and southern Appalachians: implications for Mississippi valley-type sulfide mineralization

    SciTech Connect

    Hearn, P.P.; Sutter, J.F.; Kunk, M.J.; Belkin, H.E.

    1985-01-01

    Authigenic K-feldspar has been found in rocks near Mississippi Valley-Type (MVT) sulfide mineralization in lower Paleozoic carbonate rocks of Pennsylvania, Maryland, Virginia, and Tennessee. Synthetic /sup 40/Ar//sup 39/Ar age spectra for the authigenic K-feldspar yield Carboniferous ages. Mass balance calculations indicate that the formation of the K-feldspar involved the flux of multiple pore volumes of fluid through the rocks. Estimates of vapor-liquid ratios and microthermometric homogenization temperatures of primary fluid inclusions in K-feldspar overgrowths, the presence of halite daughter crystals in some associated carbonate-hosted inclusions, and low whole-rock Cl/Br ratios indicate the K-feldspar formed by the interaction of connate brines with siliciclastic debris at temperatures between 100/sup 0/ and 200/sup 0/C. The common occurrence of feldspathized rocks stratigraphically below mineralized zones and the similarity of primary fluid inclusions in K-feldspar overgrowths to those observed in ore and qanque minerals suggest the authigenic K-feldspar and mineralization are coeval. The Carboniferous age suggested by /sup 40/Ar//sup 39/Ar age spectra is consistent with estimates based on (1) paleomagnetic studies and (2) analyses of sphalerite deformation fabrics. Accordingly, the authors suggest that MVT sulfide deposits in the central and southern Appalachians were emplaced by the migration of heated connate brines along structural pathways developed during the Alleghenian Orogeny.

  7. Evidence for igneous activity and implications for the origin of a fretted channel in southern Ismenius Lacus, Mars

    NASA Astrophysics Data System (ADS)

    Carruthers, Margaret W.; McGill, George E.

    1998-12-01

    Northern Arabia Terra, Mars is characterized by a complex landscape that includes fretted terrain, fretted channels, completely closed canyons, shallow troughs, and fracture-bounded depressions. The importance of ground ice in the initiation and development of these features, and of large impact structures in controlling channel courses, has long been recognized. The development of the fretted channel systems, including the integration of closed canyons, craters, and surface depressions into throughgoing channels, has previously been attributed primarily to mass-wasting processes. The two channel systems in southern Ismenius Lacus quadrangle, Mamers Valles and Ismeniae Fossae, incorporate craters of probable impact origin, but both also include irregular crater-like features and scalloped channel reaches that have characteristics not consistent with an impact origin. Some of these are, by analogy with morphologically similar features on Earth and elsewhere on Mars, reasonably interpreted as of volcanic origin. The detailed morphologies of a few diagnostic features associated with Ismeniae Fossae suggest a hydrovolcanic origin, an inference supported by the probable presence of abundant ground ice or groundwater at the time of their formation. The evidence described here for hydrovolcanism supports the inference that, in addition to mass-wasting processes, explosive excavation, intrusion-driven sublimation, subsurface erosion, and erosion by running water may have played important roles in channel formation and evolution as well. All of these processes are consistent with magma interacting with groundwater or ground ice.

  8. Magnetotelluric constraints on the fluid content in the upper mantle beneath the southern Canadian Cordillera: Implications for rheology

    NASA Astrophysics Data System (ADS)

    Rippe, Dennis; Unsworth, Martyn J.; Currie, Claire A.

    2013-10-01

    Long-period magnetotelluric data were collected on two parallel profiles extending across the southern Canadian Cordillera and used to derive models of the electrical resistivity of the crust and mantle from the Cascadia subduction zone to the Alberta Basin. In the fore arc, the resistivity models indicate an east dipping conductor and conductive mantle wedge, caused by the release of aqueous fluids from the Juan de Fuca plate. Low resistivities are also found beneath the volcanic arc, associated with water released from the subducting slab and mantle melts. Low resistivities in the back-arc upper mantle at depths less than 60 km suggest a shallow asthenosphere compared to the adjacent North American craton where the lithosphere-asthenosphere boundary is at ~200 km. The resistivity of the back-arc upper mantle was interpreted using geotherms, laboratory studies of mineral properties and melting points to determine the type and quantity of fluids present. The low resistivities in the back-arc upper mantle require aqueous fluids, with water content increasing from 0.005 wt % at 50 km to 0.03 wt % at 150 km depth. In addition, melt fractions of up to 1.5% are required at depths less than ~135 km to explain the observed resistivities. The presence of these quantities of aqueous fluids and partial melt will lower the viscosity of the upper mantle, as required by geodynamic models that include vigorous convection in the back arc to explain the observed heat flow.

  9. A 130 year record of pollution in the Suances estuary (southern Bay of Biscay): implications for environmental management.

    PubMed

    Irabien, M J; Cearreta, A; Leorri, E; Gmez, J; Viguri, J

    2008-10-01

    Geochemical composition (Al, Zn, Pb, Cd, Cu, Ni, Cr and As) and foraminiferal assemblages in surface and core sediments were determined to assess the current situation and the recent environmental transformation of the Suances estuary (southern Bay of Biscay, Spain). Dating of the historical record has been achieved using isotopic analysis ((210)Pb, (137)Cs) and two benchmark events such as the beginning of the mineral exploitation in the Reocn Pb-Zn deposits and the evolution of the chlor-alkali industry (inputs of Hg). Concentrations of Zn, Pb and Cd in both surface and core samples are remarkably higher than background values, reflecting the existence of significant amounts of polluted materials. The dramatic environmental impact of this pollution is clearly recorded by the change of the foraminiferal assemblages that even reach an afaunal stage during recent decades. Application of two different sets of Sediment Quality Guidelines confirm that they exert potential risk to the environment, and therefore if dredged they should need specific management measures. The results provide a reference database to monitor future environmental changes in the Suances estuary, particularly as regards the contaminated sediment storage and the re-colonization by autochtonous meiofauna. PMID:18760425

  10. Deposits of the most recent eruption in the Southern Mono Craters, California: Description, interpretation and implications for regional marker tephras

    NASA Astrophysics Data System (ADS)

    Bursik, Marcus; Sieh, Kerry; Meltzner, Aron

    2014-04-01

    The penultimate eruption in the Mono Craters, Mono County, CA, USA, occurred in the southern section of the volcanic chain, and is herein named the South Mono eruption. The South Mono eruption occurred in 594-648cal A.D., and its products consist of widespread Plinian and phreatomagmatic fall, surge and pyroclastic flow deposits. The explosive deposits can be broken into Basal, Orange-Brown (surge dominated) and Upper subunits. The eruptive phase represented by the Upper beds was the most intense and voluminous, dispersing tephra over a wide region of eastern CA and western NV. South Coulee was the only effusive product of the eruption, and comprises the vast majority of the c. 0.4 cu km dense-rock equivalent (DRE) volume. The tephra overlies the deposits of Wilson Butte to the south, and is correlated herein with Wood's Tephra 2, and Walker Lake and Turupah Flats regional marker tephra layers. Other dates for these regional tephras may be the result of dating ash redeposited in debris flow events following fire.

  11. A New Oviraptorid Dinosaur (Dinosauria: Oviraptorosauria) from the Late Cretaceous of Southern China and Its Paleobiogeographical Implications

    NASA Astrophysics Data System (ADS)

    Lü, Junchang; Pu, Hanyong; Kobayashi, Yoshitsugu; Xu, Li; Chang, Huali; Shang, Yuhua; Liu, Di; Lee, Yuong-Nam; Kundrát, Martin; Shen, Caizhi

    2015-07-01

    The Ganzhou area of Jiangxi Province, southern China is becoming one of the most productive oviraptorosaurian localities in the world. A new oviraptorid dinosaur was unearthed from the uppermost Upper Cretaceous Nanxiong Formation of Ganzhou area. It is characterized by an anterodorsally sloping occiput and quadrate (a feature shared with Citipati), a circular supratemporal fenestra that is much smaller than the lower temporal fenestra, and a dentary in which the dorsal margin above the external mandibular fenestra is strongly concave ventrally. The position of the anteroventral corner of the external naris in relation to the posterodorsal corner of the antorbital fenestra provides new insight into the craniofacial evolution of oviraptorosaurid dinosaurs. A phylogenetic analysis recovers the new taxon as closely related to the Mongolian Citipati. Six oviraptorid dinosaurs from the Nanxiong Formation (Ganzhou and Nanxiong) are distributed within three clades of the family. Each of the three clades from the Nanxiong Formation has close relatives in Inner Mongolia and Mongolia, and in both places each clade may have had a specific diet or occupied a different ecological niche. Oviraptorid dinosaurs were geographically widespread across Asia in the latest Cretaceous and were an important component of terrestrial ecosystems during this time.

  12. The Extent and Nature of Fluidity in Typologies of Female Sex Work in Southern India: Implications for HIV Prevention Programs

    PubMed Central

    Saggurti, Niranjan

    2012-01-01

    These authors examine the nature and extent of fluidity in defining the typology of female sex work based on the place of solicitation or place of sex or both places together, and whether sex workers belonging to a particular typology are at increased risk of HIV in southern India. Data are drawn from a cross-sectional survey conducted during 2007–2008 among mobile female sex workers (N = 5301) in four Indian states. Findings from this study address an important policy issue: Should programmatic prevention interventions be spread to cover all places of sex work or be focused on a few places that cover a large majority of sex workers? Results indicate that most female sex workers, including those who are usually hard to reach such as those who are mobile or who use homes for soliciting clients or sex, can be reached programmatically multiple times by concentrating on a smaller number of categories, such as street-, lodge-, and brothel-based sex workers. PMID:22745597

  13. Limited MHC polymorphism in the southern elephant seal: implications for MHC evolution and marine mammal population biology.

    PubMed

    Slade, R W

    1992-08-22

    Genes of the major histocompatibility complex (MHC) are highly polymorphic in most terrestrial mammal populations so far studied. Exceptions to this are typically populations that lack genome-wide diversity. Here I show that two populations of the southern elephant seal (Mirounga leonina) have low DNA restriction fragment length polymorphism at MHC loci when compared with terrestrial mammals. Limited studies on MHC polymorphism in two cetacean species suggest this is a feature of marine mammal populations in general. MHC polymorphism is thought to be maintained by balancing selection, and several types of disease-based and reproductive-based mechanisms have been proposed. For the three marine mammal species examined, the low MHC polymorphism cannot be explained by low genome-wide diversity, or by any reproductive-based selection pressure. It can, however, be explained by diminished exposure to pathogenic selection pressure compared with terrestrial mammals. Reduced exposure to pathogens would also mean that marine mammal populations may be susceptible to occasional pathogen-induced mass mortalities. PMID:1360677

  14. Improved Schmidt-hammer exposure ages for active and relict pronival ramparts in southern Norway, and their palaeoenvironmental implications

    NASA Astrophysics Data System (ADS)

    Matthews, John A.; Wilson, Peter

    2015-10-01

    Eight pronival (protalus) ramparts from alpine southern Norway were dated using Schmidt-hammer exposure-age dating (SHD) based on local high-precision linear calibration equations. SHD ages were - 1355 ± 1240 to 815 ± 1000 years for three active ramparts and 8730 ± 1050 to 14,635 ± 1060 years for five relict ramparts. Different parts of the same rampart yielded ages that were in generally good agreement. R-value frequency distributions enabled the identification single-age and mixed-age boulder populations, and the differentiation of active and relict rampart surfaces. The relict ramparts are located outside Younger Dryas glacier limits and probably formed over a period of ~ 6000 years between deglaciation (following the Last Glacial Maximum of the late Weichselian, ~ 18,000 years ago) and the end of the Younger Dryas (~ 11,700 years ago). At that time, glacial debuttressing and permafrost degradation apparently enhanced the release of rock debris from rock faces to the ramparts. The active ramparts, which are located in areas deglaciated after the Younger Dryas, are relatively uncommon in the study area due to diminished paraglacial effects and limited debris supply associated with seasonally frozen ground during the Holocene. Thus, the legacy of glaciers, glacier-permafrost interaction, and the specific type of periglacial environment must all be considered when assessing the palaeoenvironmental and palaeoclimatic significance of pronival ramparts.

  15. Possible detachment zone in Precambrian rocks of Kanjamalai Hills, Cauvery Suture Zone, Southern India: Implications to accretionary tectonics

    NASA Astrophysics Data System (ADS)

    Mohanty, D. P.; Chetty, T. R. K.

    2014-07-01

    Existence of a possible detachment zone at Elampillai region, NW margin of Kanjamalai Hills, located in the northern part of Cauvery Suture Zone (CSZ), Southern India, is reported here for the first time. Detailed structural mapping provides anatomy of the zone, which are rarely preserved in Precambrian high grade terranes. The detachment surface separates two distinct rock units of contrasting lithological and structural characters: the upper and lower units. The detachment zone is characterized by a variety of fold styles with the predominance of tight isoclinal folds with varied plunge directions, limb rotations and the hinge line variations often leading to lift-off fold like geometries and deformed sheath folds. Presence of parasitic folding and associated penetrative strains seem to be controlled by differences in mechanical stratigraphy, relative thicknesses of the competent and incompetent units, and the structural relief of the underlying basement. Our present study in conjunction with other available geological, geochemical and geochronological data from the region indicates that the structures of the detachment zone are genetically related to thrust tectonics forming a part of subduction-accretion-collision tectonic history of the Neoproterozoic Gondwana suture.

  16. Crustal structure of Precambrian terranes in the southern African subcontinent with implications for secular variation in crustal genesis

    NASA Astrophysics Data System (ADS)

    Kachingwe, Marsella; Nyblade, Andrew; Julià, Jordi

    2015-07-01

    New estimates of crustal thickness, Poisson's ratio and crustal shear wave velocity have been obtained for 39 stations in Angola, Botswana, the Democratic Republic of Congo, Malawi, Mozambique, Namibia, Rwanda, Tanzania and Zambia by modelling P-wave receiver functions using the H-κ stacking method and jointly inverting the receiver functions with Rayleigh-wave phase and group velocities. These estimates, combined with similar results from previous studies, have been examined for secular trends in Precambrian crustal structure within the southern African subcontinent. In both Archean and Proterozoic terranes we find similar Moho depths [38-39 ± 3 km SD (standard deviation)], crustal Poisson's ratio (0.26 ± 0.01 SD), mean crustal shear wave velocity (3.7 ± 0.1 km s-1 SD), and amounts of heterogeneity in the thickness of the mafic lower crust, as defined by shear wave velocities ≥4.0 km s-1. In addition, the amount of variability in these crustal parameters is similar within each individual age grouping as between age groupings. Thus, the results provide little evidence for secular variation in Precambrian crustal structure, including between Meso- and Neoarchean crust. This finding suggests that (1) continental crustal has been generated by similar processes since the Mesoarchean or (2) plate tectonic processes have reworked and modified the crust through time, erasing variations in structure resulting from crustal genesis.

  17. Plio-Pleistocene vegetation response on orbitally forced climatic cycles in Southern Europe - implications for early human environments

    NASA Astrophysics Data System (ADS)

    Bruch, Angela; Bertini, Adele

    2013-04-01

    The pace and causes of the early human colonization, in one or several migratory waves from Africa in new environments of the Eurasian continent during the Early Pleistocene, are still a matter of debate. However, climate change is considered a major driving factor of hominin evolution and dispersal patterns. In fact directly or indirectly by its severe influence on vegetation, physiography of landscape, and animal distribution, climate modulates the availability of resources. Plant fossils usually are rare or even absent at hominin sites. Thus, direct evidence on local vegetation and environment is generally missing. Independent from such localities, pollen profiles from the Mediterranean realm show the response of regional vegetation on global climate changes and cyclicity, with distinct spatial and temporal differences. Furthermore, plant fossils provide proxies for climate quantification that can be compared to the global signal, and add data to understanding the regional differentiation of Mediterranean environments. In this presentation we will discuss various palaeobotanical data from Southern Europe to assess Early Pleistocene climate and vegetation in time and space as part of the environment during the first expansions of early humans out of Africa.

  18. Presence of Zea luxurians (Durieu and Ascherson) Bird in Southern Brazil: Implications for the Conservation of Wild Relatives of Maize

    PubMed Central

    2015-01-01

    Records of the occurrence of wild relatives of maize in South American lowlands are unprecedented, especially in sympatric coexistence with landraces. This fact is relevant, because regions of occurrence of wild relatives of cultivated plants should be a priority for conservation, even if they do not correspond to the center of origin of the species. The aim of this study was to identify and characterize the wild relatives of maize in the Far West of Santa Catarina, southern Brazil. Therefore, phenotypic characterization was performed for five populations, based on 22 morphological traits deemed as fundamental for classifying the species of the genus Zea, and validated through the characterization of chromosomal knobs of two populations. The occurrence and distribution of teosinte populations were described through semi-structured interviews applied to a sample of 305 farmers. A total of 136 teosinte populations were identified; 75% of them occur spontaneously, 17% are cultivated populations, and 8% occur both ways, for the same farm. Populations that were characterized morphologically had trapezoidal fruits mostly, upright tassel branch (4–18), non-prominent main branch and glabrous glumes, with two protruding outer ribs and 8 inner ribs, on average. Cytogenetic analysis identified 10 pairs of homologous chromosomes (2n = 20) with 26 knobs, located in the terminal region of all chromosomes. The similarity of these results with the information reported in the literature indicates that the five populations of wild relatives of maize in this region of Santa Catarina belong to the botanical species Zea luxurians. PMID:26488577

  19. Review of SISA Student Dissertations on Library and Information Systems and Services in Eastern and Southern Africa.

    ERIC Educational Resources Information Center

    Chowdhury, G. G.; Tadesse, Taye T.

    1995-01-01

    Analyzes student dissertations at the School of Information Studies for Africa (SISA) at Addis Ababa University (Ethiopia) in order to present an overview of the library and information systems and services available in seven eastern and southern African countries: Ethiopia, Kenya, Malawi, Sudan, Tanzania, Uganda, and Zambia. (Author/LRW)

  20. Mafic high inertia crater floors in the southern highlands: Implications for a widespread post-impact modification process on Mars

    NASA Astrophysics Data System (ADS)

    Edwards, C. S.; Bandfield, J. L.; Rogers, D.; Christensen, P. R.

    2010-12-01

    Understanding the history of impact crater modification and alteration can provide insights into planet scale processes that have occurred throughout Martian history. We have identified a unique class of Martian craters with flat, high thermal inertia floors, mafic mineralogies, and degraded morphologies. By using physical material properties in combination with morphologic and mineralogical data, it is possible to constrain the formation and modification history of these craters and better understand the crater modification processes, including post-impact volcanism, chemical weathering and hydrothermal alteration. This class of crater is prevalent throughout the southern highlands of Mars. The craters studied have degraded walls and rims, no central peak, no clearly visible ejecta deposits, an average diameter of ~52km (ranging in size from 18.5km to 179km), and occur almost exclusively in the southern highlands indicating an old formation age. The thermal inertia values derived from Thermal Emission Imaging System (THEMIS) measurements of crater floors are consistent with competent rocky material, while the walls and surrounding plains are composed of a less cohesive material. We have used THEMIS, Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), and Thermal Emission Spectrometer (TES) data to constrain the compositional variability of ~60 sites with the highest thermal inertia values. In general, the crater floors have higher abundances of mafic minerals (e.g. pyroxenes and olivine), while the surrounding plains have lower abundances of mafic minerals but show an increase in high-Si phase abundance. The composition, morphology, and distribution suggest that old, flat floored craters were resurfaced by a post-impact process that resulted in material significantly more mafic than the surrounding terrain. A possible formation mechanism may be related to inflationary volcanism associated with the impact [Schultz, 1976]. In this model, during the impact event, the crust is fractured providing a conduit for magma to erupt onto the surface and infill the original crater floor. The source of this magma is not well constrained and may be related to the unloading of the early Martian mantle and crust, resulting in partial melting of the underlying material. The mineralogy of these materials is consistent with a picritic basalt and indicates a primitive magma source, such as the Martian mantle. We have identified and characterized a unique class of Martian craters that has gone previously unstudied. If the distribution of this crater type is considered and the proposed model is correct, it is likely that inflationary volcanism is an important widespread process on Mars that has gone previously undocumented. This process could be responsible for extended periods of hydrothermal activity, a source of energy for altering materials, and may indicate high crustal heat flow early in Mars history. Schultz, P. H. (1976), Floor-fractured lunar craters, Earth, Moon, and Planets, 15(3).

  1. Internet accessibility and usage among urban adolescents in Southern California: implications for web-based health research.

    PubMed

    Sun, Ping; Unger, Jennifer B; Palmer, Paula H; Gallaher, Peggy; Chou, Chih-Ping; Baezconde-Garbanati, Lourdes; Sussman, Steve; Johnson, C Anderson

    2005-10-01

    The World Wide Web (WWW) poses a distinct capability to offer interventions tailored to the individual's characteristics. To fine tune the tailoring process, studies are needed to explore how Internet accessibility and usage are related to demographic, psychosocial, behavioral, and other health related characteristics. This study was based on a cross-sectional survey conducted on 2373 7th grade students of various ethnic groups in Southern California. Measures of Internet use included Internet use at school or at home, Email use, chat-room use, and Internet favoring. Logistic regressions were conducted to assess the associations between Internet uses with selected demographic, psychosocial, behavioral variables and self-reported health statuses. The proportion of students who could access the Internet at school or home was 90% and 40%, separately. Nearly all (99%) of the respondents could access the Internet either at school or at home. Higher SES and Asian ethnicity were associated with higher internet use. Among those who could access the Internet and after adjusting for the selected demographic and psychosocial variables, depression was positively related with chat-room use and using the Internet longer than 1 hour per day at home, and hostility was positively related with Internet favoring (All ORs = 1.2 for +1 STD, p < 0.05). Less parental monitoring and more unsupervised time were positively related to email use, chat-room use, and at home Internet use (ORs for +1 STD ranged from 1.2 to 2.0, all p < 0.05), but not related to at school Internet use. Substance use was positively related to email use, chat-room use, and at home Internet use (OR for "used" vs. "not used" ranged from 1.2 to 4.0, p < 0.05). Self-reported health problems were associated with higher levels of Internet use at home but lower levels of Internet use at school. More physical activity was related to more email use (OR = 1.3 for +1 STD), chat room use (OR = 1.2 for +1 STD), and at school ever Internet use (OR = 1.2 for +1 STD, all p < 0.05). Body mass index was not related to any of the Internet use-related measures. In this ethnically diverse sample of Southern California 7(th) grade students, 99% could access the Internet at school and/or at home. This suggests that the Internet is already a potential venue for large scale health communication studies. Adolescents with more psychosocial risk factors or detrimental health behaviors were more likely to use the Internet. Therefore, if used properly, Internet interventions could effectively address the high risk populations. Additional research is needed to gain a more complete understanding of the positive and negative consequences of Internet use among adolescents. PMID:16232037

  2. Data assimilative hindcast on the Southern Flank of Georges Bank during May 1999: frontal circulation and implications

    NASA Astrophysics Data System (ADS)

    Aretxabaleta, Alfredo; Manning, James; Werner, Francisco E.; Smith, Keston; Blanton, Brian O.; Lynch, Daniel R.

    2005-05-01

    The circulation of the tidal front along the Southern Flank of the Georges Bank region during May 1999 is examined for the purpose of understanding the transport of larval fish for periods of days to a week. Assimilation of shipboard ADCP data from several Georges Bank cruises into 3-D models is used to produce the hindcast circulation. Adjustments to boundary nodal elevations are estimated to minimize the misfit between model and observations both in frequency and time domains as described in Lynch and Hannah (J. Atmos. Oceanic Technol 18 (2001) 962) and Lynch and Naimie (Cont. Shelf Res. 22 (2002) 2191). An intercomparison of different methods of applying the adjustments is completed using drifter records and dye patch trajectories to provide a measure of skill. The computed flow fields show a skill of 2.4kmday-1 when compared to (unassimilated) drifter trajectories. The tracking of a dye-patch recovers an observed near-bottom cross-bank flow component that is not present without assimilation. Using these flow fields we then investigate the importance of the front as a retention mechanism using passive particle simulations. Wind, heat flux, and tides control the circulation across and along the tidal mixing front. Three 3-day time periods, before, during and after a wind event during May 1999 were studied. Model simulations suggest a highly variable cell-like circulation in the frontal region (onshore near the bottom, upwelling shoalward of the front, offshore at mid-depth and downwelling seaward of the front) that controls the exchange and retention of particles. During the periods when the cell-like circulation is active the highest accumulation of particles occurs in the areas surrounding the front.

  3. Controls on large landslide distribution and implications for the geomorphic evolution of the southern interior Columbia River basin

    USGS Publications Warehouse

    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.

  4. Geochemical studies of hotspot volcanism in the Southern Pacific and its implications for mantle structure and dynamics

    SciTech Connect

    Cheng, Q.C.

    1989-01-01

    This dissertation dedicates to geochemical investigations of hotspot volcanism in the Southern Pacific, by means of detailed, combined major, trace element and isotope studies of individual islands and island/seamount chains. Chapter 2 describes Sr, Nd and Pb isotopic studies of the whole Louisville Seamount Chain (LSC), to investigate long term evolution of hotspot source. Leaching experiments were conducted to study seawater alteration effects on both Sr and Nd isotopic compositions. Chapter 3 studies the Easter Island-Seamount Chain (EISC). Results from this study are most consistent with a hotspot origin for the EISC. Chapter 4 involves detailed geochemical studies of Tahiti, including Teahitia and Mehetia, from Society Islands. Both major and trace element compositions change systematically with time, indicating a progressive decrease in both the extent of partial melting and the amount of plume component. Isotope data are well correlated on the {sup 87}Sr/{sup 86}Sr vs. {sup 143}Nd/{sup 144}Nd diagram, suggesting mixing between two distinct end-members. Secular isotopic variation pattern records volcanic activities on Tahiti, which links geochemical characteristics to mantle processes of hotspot volcanism. A mantle blob model is preferred for island formation. Most existing OIB isotopic data can be explained by mixing of a small amount of sediments with MORB-like sources. These findings provide further geochemical evidence for a subducted slab origin of OIB sources. Chapter 5 synthesizes the author's own data and those from the literature, to evaluate mantle heterogeneities, origin and evolution of hotspot sources, and mantle structure and dynamics.

  5. Occurrence of organophosphorus flame retardants in indoor dust in multiple microenvironments of southern China and implications for human exposure.

    PubMed

    He, Chun-Tao; Zheng, Jing; Qiao, Lin; Chen, She-Jun; Yang, Jun-Zhi; Yuan, Jian-Gang; Yang, Zhong-Yi; Mai, Bi-Xian

    2015-08-01

    Organophosphorus flame retardants (OPFRs) are important alternatives to brominated flame retardants (BFRs), but information on their contamination of the environment in China is rare. We examined the occurrence of 12 OPFRs in indoor dust in four microenvironments of southern China, including a rural electronic waste (e-waste) recycling area, a rural non-e-waste area, urban homes, and urban college dormitory rooms. The OPFR concentrations (with a median of 25.0 μg g(-1)) were highest in the e-waste area, and the concentrations in other three areas were lower and comparable (7.48-11.0 μg g(-1)). The levels of OPFRs in the present study were generally relatively lower than the levels of OPFRs found in Europe, Canada, and Japan because BFRs are still widely used as the major FRs in China. The composition profile of OPFRs in the e-waste area was dominated by tricresyl phosphate (TCP) (accounting for 40.7%, on average), while tris(2-chloroethyl) phosphate (TCEP) was the most abundant OPFR (64.4%) in the urban areas (homes and college dormitories). These two distribution patterns represent two OPFR sources (i.e., emissions from past e-waste and from current household products and building materials). The difference in the OPFR profiles in the rural area relative to the OPFR profiles in the urban and e-waste areas suggests that the occurrence of OPFRs is due mainly to emissions from characteristic household products in rural homes. Although human exposures to all the OPFRs were under the reference doses, the health risk for residents in the e-waste area is a concern, considering the poor sanitary conditions in this area and exposure from other sources. PMID:25898308

  6. Climatic Implications of the Observed Temperature Dependence of the Liquid Water Path of Low Clouds in the Southern Great Plains

    NASA Technical Reports Server (NTRS)

    DelGenio, Anthony

    1999-01-01

    Satellite observations of low-level clouds have challenged the assumption that adiabatic liquid water content combined with constant physical thickness will lead to a negative cloud optics feedback in a decadal climate change. We explore the reasons for the satellite results using four years of surface remote sensing data from the Atmospheric Radiation Measurement Program Cloud and Radiation Testbed site in the Southern Great Plains of the United States. We find that low cloud liquid water path is approximately invariant with temperature in winter but decreases strongly with temperature in summer, consistent with the satellite inferences at this latitude. This behavior occurs because liquid water content shows no detectable temperature dependence while cloud physical thickness decreases with warming. Thinning of clouds with warming is observed on seasonal, synoptic, and diurnal time scales; it is most obvious in the warm sectors of baroclinic waves. Although cloud top is observed to slightly descend with warming, the primary cause of thinning, is the ascent of cloud base due to the reduction in surface relative humidity and the concomitant increase in the lifting condensation level of surface air. Low cloud liquid water path is not observed to be a continuous function of temperature. Rather, the behavior we observe is best explained as a transition in the frequency of occurrence of different boundary layer types. At cold temperatures, a mixture of stratified and convective boundary layers is observed, leading to a broad distribution of liquid water path values, while at warm temperatures, only convective boundary layers with small liquid water paths, some of them decoupled, are observed. Our results, combined with the earlier satellite inferences, imply that the commonly quoted 1.5C lower limit for the equilibrium global climate sensitivity to a doubling of CO2 which is based on models with near-adiabatic liquid water behavior and constant physical thickness, should be revised upward.

  7. Climatic Implications of the Observed Temperature Dependence of the Liquid Water Path of Low Clouds in the Southern Great Plains

    NASA Technical Reports Server (NTRS)

    DelGenio, Anthony D.; Wolf, Audrey B.

    1999-01-01

    Satellite observations of low-level clouds have challenged the assumption that adiabatic liquid water content combined with constant physical thickness will lead to a negative cloud optics feedback in a decadal climate change. We explore the reasons for the satellite results using four years of surface remote sensing data from the Atmospheric Radiation Measurement Program Cloud and Radiation Testbed site in the Southern Great Plains of the United States. We find that low cloud liquid water path is approximately invariant with temperature in winter but decreases strongly with temperature in summer, consistent with the satellite inferences at this latitude. This behavior occurs because liquid water content shows no detectable temperature dependence while cloud physical thickness decreases with warming. Thinning of clouds with warming is observed on seasonal, synoptic, and diurnal time scales; it is most obvious in the warm sectors of baroclinic waves. Although cloud top is observed to slightly descend with warming, the primary cause of thinning is the ascent of cloud base due to the reduction in surface relative humidity and the concomitant increase in the lifting condensation level of surface air. Low cloud liquid water path is not observed to be a continuous function of temperature. Rather, the behavior we observe is best explained as a transition in the frequency of occurrence of different boundary layer types: At cold temperatures, a mixture of stratified and convective boundary layers is observed, leading to a broad distribution of liquid water path values, while at warm temperatures, only convective boundary layers with small liquid water paths, some of them decoupled, are observed. Our results, combined with the earlier satellite inferences, imply that the commonly quoted 1.50 C lower limit for the equilibrium global climate sensitivity to a doubling of CO2, which is based on models with near-adiabatic liquid water behavior and constant physical thickness, should be revised upward.

  8. Anomalous crustal and lithospheric mantle structure of southern part of the Vindhyan Basin and its geodynamic implications

    NASA Astrophysics Data System (ADS)

    Pandey, O. P.; Srivastava, R. P.; Vedanti, N.; Dutta, S.; Dimri, V. P.

    2014-09-01

    Tectonically active Vindhyan intracratonic basin situated in central India, forms one of the largest Proterozoic sedimentary basins of the world. Possibility of hydrocarbon occurrences in thick sediments of the southern part of this basin, has led to surge in geological and geophysical investigations by various agencies. An attempt to synthesize such multiparametric data in an integrated manner, has provided a new understanding to the prevailing crustal configuration, thermal regime and nature of its geodynamic evolution. Apparently, this region has been subjected to sustained uplift, erosion and magmatism followed by crustal extension, rifting and subsidence due to episodic thermal interaction of the crust with the hot underlying mantle. Almost 5-6 km thick sedimentation took place in the deep faulted Jabera Basin, either directly over the Bijawar/Mahakoshal group of mafic rocks or high velocity-high density exhumed middle part of the crust. Detailed gravity observations indicate further extension of the basin probably beyond NSL rift in the south. A high heat flow of about 78 mW/m2 has also been estimated for this basin, which is characterized by extremely high Moho temperatures (exceeding 1000 °C) and mantle heat flow (56 mW/m2) besides a very thin lithospheric lid of only about 50 km. Many areas of this terrain are thickly underplated by infused magmas and from some segments, granitic-gneissic upper crust has either been completely eroded or now only a thin veneer of such rocks exists due to sustained exhumation of deep seated rocks. A 5-8 km thick retrogressed metasomatized zone, with significantly reduced velocities, has also been identified around mid to lower crustal transition.

  9. High-pressure metamorphism in the southern New England Orogen: Implications for long-lived accretionary orogenesis in eastern Australia

    NASA Astrophysics Data System (ADS)

    Phillips, G.; Offler, R.; Rubatto, D.; Phillips, D.

    2015-09-01

    New geochemical, metamorphic, and isotopic data are presented from high-pressure metamorphic rocks in the southern New England Orogen (eastern Australia). Conventional and optimal thermobarometry are augmented by U-Pb zircon and 40Ar/39Ar phengite dating to define pressure-temperature-time (P-T-t) histories for the rocks. The P-T-t histories are compared with competing geodynamic models for the Tasmanides, which can be summarized as (i) a retreating orogen model, the Tasmanides formed above a continuous, west dipping, and eastward retreating subduction zone, and (ii) a punctuated orogen model, the Tasmanides formed by several arc accretion, subduction flip, and/or transference events. Whereas both scenarios are potentially supported by the new data, an overlap between the timing of metamorphic recrystallization and key stages of Tasmanides evolution favors a relationship between a single, long-lived subduction zone and the formation, exhumation, and exposure of the high-pressure rocks. By comparison with the retreating orogen model, the following links with the P-T-t histories emerge: (i) exhumation and underplating of oceanic eclogite during the Delamerian Orogeny, (ii) recrystallization of underplated and exhuming high-pressure rocks at amphibolite facies conditions coeval with a period of rollback, and (iii) selective recrystallization of high-pressure rocks at blueschist facies conditions, reflecting metamorphism in a cooled subduction zone. The retreating orogen model can also account for the anomalous location of the Cambrian-Ordovician high-pressure rocks in the Devonian-Carboniferous New England Orogen, where sequential rollback cycles detached and translated parts of the leading edge of the overriding plate to the next, younger orogenic cycle.

  10. Anatomy and implications of bioturbated beds in black shale sequences: Examples from the Jurassic Posidonienschiefer (Southern Germany)

    SciTech Connect

    Savrda, C.E. ); Bottjer, D.J. )

    1989-08-01

    Sequences of organic-rich, laminated mudrocks deposited under oxygen-deficient conditions commonly contain interbedded, bioturbated intervals that reflect periodic episodes of improved bottom-water oxygenation. On the basis of differential ichnofossil preservation, many of these redox event beds are divisible into two parts: a primary stratum and a piped zone. Primary strata, characterized by vague burrow mottling and the lack of discrete biogenic structures, represent sediments that have passed through the surface mixed layer. Piped zones, which occur at the interfaces between primary strata and subjacent darker laminated strata, are characterized by well-preserved, discrete trace fossils that represent the earliest emplacement of transition layer burrows in sediments that have not passed through the surface mixed layer. The anatomy of these bioturbated beds can be used to infer the relative durations and magnitudes of the oxygenation events responsible. Based on the thickness of primary strata and the extent of cross-cutting of ishnofossils in the piped zones, two general types or redox events can be recognized: (1) short-term events, and (2) extended events. Systematic increases in burrow diameter, depth of burrow penetration, and diversity of trace-fossil assemblages within piped zones provide evidence for increasing magnitude of oxygenation episodes. The utility and limitations of this approach are illustrated through an example application to twelve bioturbated intervals within black shales of the Jurassic Posidonienschiefer of southern Germany. These beds can be categorized as one of three types, each of which are interpreted to reflect differences in oxygenation-event histories.

  11. Analysis of coastal sea-level station records and implications for tsunami monitoring in the Adriatic Apulia region, southern Italy

    NASA Astrophysics Data System (ADS)

    Bressan, Lidia; Tinti, Stefano; Tallarico, Andrea

    2015-04-01

    The region of Apulia, southern Italy, was theater of one of the largest tsunami disaster in Italian history (the 30 July 1627 event) and is considered to be exposed to tsunami hazard coming from local Italian sources as well as from sources on the eastern side of the Adriatic and from the Ionian sea, including the Hellenic Arc earthquakes. Scientific interest for tsunami studies and monitoring in the region is only recent and this theme was specifically addressed by the international project OTRIONS, coordinated by the University of Bari. In the frame of this project the University of Bologna contributed to the analysis of the tsunami hazard and to the evaluation of the regional tide-gauge network with the scope of assessing its adequacy for tsunami monitoring. This latter is the main topic of the present work. In eastern Apulia, facing the Adriatic sea, the sea-level data network is sufficiently dense being formed of stations of the Italian tide-gauge network (Rete Mareografica Nazionale, RMN), of four additional stations operated by the Apulia Port Authority (in Brindisi, Ischitella, Manfredonia and Porto Cesareo) and of two more stations that were installed in the harbours of Barletta and Monopoli in the frame of the project OTRIONS with real-time data transmission and 1-sec sampling period. Pre-processing of the sea-level data of these stations included quality check and spectral analysis. Where the sampling rate was adequate, the records were also examined by means of the specific tools provided by the TEDA package. This is a Tsunami Early Detection Algorithm, developed by the Tsunami Research Team of the University of Bologna, that allows one to characterize the sea-level background signal in the typical tsunami frequency window (from 1 to several minutes) and consequently to optimize TEDA parameters for an efficient tsunami detection. The results of the analysis show stability of the spectral content and seasonal variations.

  12. Compositional diversity of Late Cenozoic basalts in a transect across the southern Washington Cascades: Implications for subduction zone magmatism

    SciTech Connect

    Leeman, W.P. ); Smith, D.R. ); Hildreth, W. ); Palacz, Z.; Rogers, N. )

    1990-11-10

    Major volcanoes of the Southern Washington Cascades (SWC) include the large quaternary stratovolcanoes of Mount St. Helens (MSH) and Mount Adams (MA) and the Indian Heaven (IH) and Simcoe Mountain (SIM) volcanic fields. There are significant differences among these volcanic centers in terms of their composition and evolutionary history. The authors conclude that subducted fluids and sediments do not play an essential role in producing these magmas. Rather, they infer that they formed by variable degree melting of a mixed mantle source consisting mainly of heterogeneously distributed OIB and mid-ocean ridge basalt source domains. Relatively minor occurrences of high field strength element (HFSE) depleted arclike basalts may reflect the presence of a small proportion of slab-metasomatized subarc mantle. The juxtaposition of such different mantle domains within the lithospheric mantle is viewed as a consequence of (1) tectonic mixing associated with accretion of oceanic and island arc terranes along the Pacific margin of North America prior to Neogene time, and possibly (2) a seaward jump in the locus of subduction at about 40 Ma. The Cascades arc is unusual in that the subducting oceanic plate is very young and hot. They suggest that slab dehydration outboard of the volcanic front resulted in a diminished role of aqueous fluids in generating or subsequently modifying SWC magmas compared to the situation at most convergent margins. Furthermore, with low fluid flux conditions, basalt generation is presumably triggered by other processes that increase the temperature of the mantle wedge (e.g., convective mantle flow, shear heating, etc.).

  13. Hillslope response to knickpoint migration in the Southern Appalachians: Implications for the evolution of post-orogenic landscapes

    USGS Publications Warehouse

    Wegmann, S.F.G.; Franke, K.L.; Hughes, S.; Lewis, R.Q.; Lyons, N.; Paris, P.; Ross, K.; Bauer, J.B.; Witt, A.C.

    2011-01-01

    The southern Appalachians represent a landscape characterized by locally high topographic relief, steep slopes, and frequent mass movement in the absence of significant tectonic forcing for at least the last 200 Ma. The fundamental processes responsible for landscape evolution in a post-orogenic landscape remain enigmatic. The non-glaciated Cullasaja River basin of south-western North Carolina, with uniform lithology, frequent debris flows, and the availability of high-resolution airborne lidar DEMs, is an ideal natural setting to study landscape evolution in a post-orogenic landscape through the lens of hillslope-channel coupling. This investigation is limited to channels with upslope contributing areas >2.7 km2, a conservative estimate of the transition from fluvial to debris-flow dominated channel processes. Values of normalized hypsometry, hypsometric integral, and mean slope vs elevation are used for 14 tributary basins and the Cullasaja basin as a whole to characterize landscape evolution following upstream knickpoint migration. Results highlight the existence of a transient spatial relationship between knickpoints present along the fluvial network of the Cullasaja basin and adjacent hillslopes. Metrics of topography (relief, slope gradient) and hillslope activity (landslide frequency) exhibit significant downstream increases below the current position of major knickpoints. The transient effect of knickpoint-driven channel incision on basin hillslopes is captured by measuring the relief, mean slope steepness, and mass movement frequency of tributary basins and comparing these results with the distance from major knickpoints along the Cullasaja River. A conceptual model of area-elevation and slope distributions is presented that may be representative of post-orogenic landscape evolution in analogous geologic settings. Importantly, the model explains how knickpoint migration and channel- hillslope coupling is an important factor in tectonically-inactive (i.e. post-orogenic) orogens for the maintenance of significant relief, steep slopes, and weathering-limited hillslopes. ?? 2011 John Wiley & Sons, Ltd.

  14. Submarine canyon morphologies in the Gulf of Palermo (Southern Tyrrhenian Sea) and possible implications for geo-hazard

    NASA Astrophysics Data System (ADS)

    Lo Iacono, Claudio; Sulli, Attilio; Agate, Mauro; Lo Presti, Valeria; Pepe, Fabrizio; Catalano, Raimondo

    2011-03-01

    The continental shelf and the upper slope of the Gulf of Palermo (Southern Tyrrhenian Sea) in the depth interval ranging from 50 to 1,500 m were mapped for the first time with Multi Beam echosounder and high resolution seismic. Seven submarine canyons are confined to the upper slope or indent the shelf-edge and enter the Palermo intraslope basin at a depth of around 1,300 m. The canyons evolved through concurrent top-down turbiditic processes and bottom-up retrogressive mass failures. Most of the mass failure features of the area are related to canyon-shaping processes and only few of them are not confined to the upper slope. In general, these features probably do not represent a significant tsunami hazard along the coast. The geological element that controls the evolution of the canyons and induces sediment instability corresponds to the steep slope gradient, especially in the western sector of the Gulf, where the steepest canyons are located. The structural features mapped in the Palermo offshore contributed to the regulation of mass failure processes in the area, with direct faults and antiform structures coinciding with some of the canyon heads. Furthermore, the occurrence of pockmarks and highs that probably consist of authigenic carbonates above faulted and folded strata suggests a local relationship between structural control, fluid escape processes and mass failure. This paper presents a valuable high-resolution morphologic dataset of the Gulf of Palermo, which constitutes a reliable base for evaluating the geo-hazard potential related to slope failure in the area.

  15. Multi-scale structural and kinematic analysis of a Neoarchean shear zone in northeastern Minnesota: Implications for assembly of the southern Superior Province

    NASA Astrophysics Data System (ADS)

    Dyess, Jonathan

    This dissertation is a multi-scale structural and kinematic analysis of the Shagawa Lake shear zone in northeastern Minnesota (USA). The Neoarchean Shagawa Lake shear zone is an ~70 km long ~7 km wide subvertical package of L-S tectonites located within the Wawa Subprovince of the Archean Superior Province. In this dissertation, I (1) discuss a new method for mapping regional tectonic fabrics using high-resolution LiDAR altimetry data; (2) examine the geometric relationships between metamorphic foliation, elongation lineation, vorticity, and non-coaxial shear direction within individual L-S tectonites; and (3) incorporate LiDAR, field, and microstructural data sets into a comprehensive structural and kinematic analysis of the Western Shagawa Lake shear zone. Lastly, I discuss implications for assembly of the southern Superior Province. In Chapter one I examine an Archean granite-greenstone terrane in NE Minnesota to illustrate the application of high-resolution LiDAR altimetry to mapping regional tectonic fabrics in forested, glaciated areas. I describe the recognition of lineaments and distinguishing between tectonic and glacial lineament fabrics. I use a 1-m posted LiDAR derived bare-earth digital elevation model (DEM) to construct multiple shaded-relief images for lineament mapping with sun elevation of 45? and varying sun azimuth in 45? intervals. Two suites of lineaments are apparent. Suite A has a unimodal orientation, mean trend of 035, and consists of short (> 2 km long) lineaments within sediment deposits and bedrock. Suite B lineaments, which are longer (1-30 km) than those of suite A, have a quasi-bimodal orientation distribution, with maximum trends of 065 and 090. Only one lineament suite is visible in areas where suites A and B are parallel. I interpret suite A as a surficial geomorphologic fabric related to recent glaciation, and suite B as a proxy for the regional tectonic fabric. In Chapter two I present a detailed kinematic study of seven Neoarchean L-S tectonite samples in order to determine vorticity and non-coaxial shear direction relative to foliation and elongation lineation. I compare data from thin-sections, x-ray computed tomography, and quartz crystallographic fabric analysis to monoclinic shear models to determine vorticity and better understand geometric relationships between vorticity, non-coaxial shear direction, foliation, and elongation lineation. Kinematic indicators in thin-section and image slices from X-ray computed tomography consistently record asymmetric microstructural fabrics in foliation-normal lineation-parallel planes, whereas planes normal to foliation and elongation lineation display dominantly symmetric microstructural fabrics. Data indicate that tectonites record non-coaxial shear broadly parallel to elongation lineation regardless of lineation geographic orientation. In Chapter three I present a detailed structural and kinematic study of the eastern Shagawa Lake shear zone. I recognize no strain partitioning, crosscutting relationships between multiple shear events, or metamorphic overprinting within the study area. L-S tectonites record roughly isobaric/isothermal greenschist facies metamorphic conditions across the Shagawa Lake shear zone. The Shagawa Lake shear zone records a broad deformation event characterized by dominantly dip-slip shear in varying directions with multiple shear-senses. Structural and kinematic data indicate that the Shagawa Lake shear zone records deformation within a rheologically weak crust. These data are inconsistent with existing sagduction-diapirism/crustal overturn models and with plate-tectonic/terrane accretion scenarios for assembly of the southern Superior Province. Channel flow induced collapse and exhumation of high-grade crustal material during regional shortening provides a plausible mechanism for assembly of the southern Superior Province and is consistent with the rheological implications of this study. (Abstract shortened by UMI.).

  16. Volcanic risk and tourism in southern Iceland: Implications for hazard, risk and emergency response education and training

    NASA Astrophysics Data System (ADS)

    Bird, Deanne K.; Gisladottir, Gudrun; Dominey-Howes, Dale

    2010-01-01

    This paper examines the relationship between volcanic risk and the tourism sector in southern Iceland and the complex challenge emergency management officials face in developing effective volcanic risk mitigation strategies. An early warning system and emergency response procedures were developed for communities surrounding Katla, the volcano underlying the Mýrdalsjökull ice cap. However, prior to and during the 2007 tourist season these mitigation efforts were not effectively communicated to stakeholders located in the tourist destination of Þórsmörk despite its location within the hazard zone of Katla. The hazard zone represents the potential extent of a catastrophic jökulhlaup (glacial outburst flood). Furthermore, volcanic risk mitigation efforts in Þórsmörk were based solely on information derived from physical investigations of volcanic hazards. They did not consider the human dimension of risk. In order to address this gap and provide support to current risk mitigation efforts, questionnaire surveys were used to investigate tourists' and tourism employees' hazard knowledge, risk perception, adoption of personal preparedness measures, predicted behaviour if faced with a Katla eruption and views on education. Results indicate that tourists lack hazard knowledge and they do not adopt preparedness measures to deal with the consequences of an eruption. Despite a high level of risk perception, tourism employees lack knowledge about the early warning system and emergency response procedures. Results show that tourists are positive about receiving information concerning Katla and its hazards and therefore, the reticence of tourism employees with respect to disseminating hazard information is unjustified. In order to improve the tourism sector's collective capacity to positively respond during a future eruption, recommendations are made to ensure adequate dissemination of hazard, risk and emergency response information. Most importantly education campaigns should focus on: (a) increasing tourists' knowledge of Katla, jökulhlaup and other volcanic hazards and (b) increasing tourist and employee awareness of the early warning and information system and appropriate behavioural response if a warning is issued. Further, tourism employees should be required to participate in emergency training and evacuation exercises annually. These efforts are timely given that Katla is expected to erupt in the near future and international tourism is an expanding industry in Þórsmörk.

  17. Simulated Damping of Periodic Fluctuations in Net Infiltration Within a Thick Unsaturated Zone in Southern Nevada: Implications For Radionuclide Transport

    NASA Astrophysics Data System (ADS)

    Ebel, B. A.; Nimmo, J. R.

    2009-12-01

    Arid and semiarid regions are historically preferred sites for radionuclide generating activities and waste disposal, in part because their unsaturated zones, typically having large thickness and low water content, are expected to inhibit the transport of contaminants to groundwater supplies. Through portions of the unsaturated zone that are heavily fractured, however, there is concern that transport in preferential flow paths might be relatively rapid on an episodic basis. Even so, fractured zones are commonly interrupted by lithologic units without substantial fractures, through which unsaturated flow might always be diffuse so as to damp out episodic fluctuations. In unsaturated-zone fractured units below such damping units, the initiation of preferential flow theoretically hinges on reaching a threshold moisture state, which depends on the magnitude of pressure and flux signals resulting from natural periodic variations in net infiltration. In diffuse unsaturated flow, periodic oscillations are damped to a quasi-steady state at sufficient distance from the inflow boundary. The resulting matric potential may be insufficient to trigger or sustain fracture flow through unsaturated media lying beneath those that facilitate damping. In general, shorter-period oscillations, longer distances of diffuse flow, and drier matrix conditions are conducive to damping. In this work we examine the damping of periodic recharge signals to a quasi-steady value, using analytical solutions for diffuse unsaturated flow, at Rainier Mesa and Shoshone Mountain in southern Nevada. Underground nuclear tests in previous decades introduced radionuclides into the unsaturated subsurface at these sites. Both sites have possible damping units greater than 100 m thick that are believed to be dominated by diffuse flow. Below these damping units lie fractured rocks in which preferential flow could resume, especially if the damping units are not sufficiently thick or dry. Effective damping of periodic recharge variations has the potential to suppress preferential flow initiation. Our simulations suggest that annual to decadal variations in net infiltration at these semiarid locations are damped to quasi-steady fluxes if diffuse unsaturated flow dominates within the thickness of the selected damping units. Sensitivity analysis shows that the estimated period to achieve damping is most sensitive to the unsaturated hydraulic properties of the media.

  18. A temporary pond in the Early Cretaceous of southern England: palaeoclimatic implications of nonmarine "Purbeck-Wealden" ostracod faunas

    NASA Astrophysics Data System (ADS)

    Horne, D. J.

    2009-04-01

    Excavation of the partial skeleton of an Iguanodon from the Upper Weald Clay (Barremian, Early Cretaceous) at Smokejacks Brickworks near Ockley, Surrey, UK included detailed sampling for micropalaeontological and palynological and studies (Nye et al., 2008). Rich and well-preserved non-marine assemblages of pollen and spores include early angiosperms as well as freshwater green algae. Taphonomic analyses show the ostracod assemblages to be autochthonous thanatocoenoses, indicative of local environment at the time of deposition. Using a palaeobiological approach, the ostracods and palynomorphs demonstrate temporary / ephemeral freshwater conditions at the time when the Iguanodon died and the carcase was buried. Ostracod "faunicycles" in "Purbeck-Wealden" deposits may represent salinity variations in non-marine water-bodies, influenced by the balance between precipitation and evaporation, and/or the relative abundance of permanent and temporary waterbodies in the landscape; many assemblages resulted from post-mortem mixing, perhaps during flood events (Horne, 2002). Faunal alternations may therefore reflect shifts of the boundary between warm temperate and paratropical climate in the Early Cretaceous of NW Europe. The previously rejected suggestion that such assemblage variations record Milankovitch cyclicity deserves to be reconsidered, as does the possibility that they reflect changes on sub-Milankovitch timescales. Climate variability may have influenced the differential evolutionary success of sexual, mixed and parthenogenetic reproductive strategies in nonmarine ostracods. Latitudinally restricted distribution patterns and wind dispersal of resting eggs offer potential for inferring global climate patterns from ostracod palaeobiogeography, although dispersal by large animals (e.g., crocodiles, pterosaurs) is likely to have confused any aeolian transport patterns. References Horne, D. J. 2002. Ostracod biostratigraphy and palaeoecology of the Purbeck Limestone Group in southern England. Special Papers in Palaeontology, 68, 1-18, 2 pls. Nye, E., Feist-Burkhardt, S., Horne, D. J., Ross, A. J. & Whittaker, J. E. (2008) The palaeoenvironment associated with a partial Iguanodon skeleton from the Upper Weald Clay (Barremian, Early Cretaceous) at Smokejacks Brickworks (Ockley, Surrey, UK), based on palynomorphs and ostracods. Cretaceous Research, 29, 417-444.

  19. Constraining the age of Liuqu Conglomerate, southern Tibet: Implications for tectonic evolution of the Indus-Yarlung Suture Zone

    NASA Astrophysics Data System (ADS)

    Li, G.; Sandiford, M.; Kohn, B.

    2014-12-01

    The depositional age and provenance of the Liuqu Conglomerate (LC), distributed along the Indus-Yarlung suture zone (IYSZ) in South Tibet, remain controversial, leading to different interpretations, such as a Paleogene basin deposited during India-Asia collision (Wang et al., 2010) or the result of the collision between India and an intra-oceanic arc (Aitchison et al., 2007). Here, we report low-temperature thermochronometry data (apatite fission track, apatite and zircon U-Th/He) for the LC in the Xigaze area, to constrain its depositional age, provenance and burial-exhumation history. Five samples from Liuqu yielded consistent AFT ages of ~6-8Ma, and dispersed single-grain AFT ages of six samples range from ~ 140 to 5 Ma, and single grain AFT ages for grains with >0.4 Cl (wt%) content was calculated three age-peaks of ~16.4 ±3.0, 37.3 ± 6.4 and 89.5 ± 22.2 Ma. Four groups of detrital ZHe ages, including 18 scattered single grain ages in the range of ~20 - 107.9 Ma, yielded four age peaks of ~20, 37, 66 and 104 Ma. We interpret the AHe ages of the LC as having been completely thermally reset, while AFT ages have been partially annealed and ZHe ages have not been thermally reset, suggesting that the post-depositional maximum temperature of the LC was > 80 °C and < 110°C. Collectively, our results indicate that the Liuqu Conglomerate was probably deposited in the Early Miocene time, similar to the Qiuwu-Dazhuka conglomerates which are located in the northern part of the IYSZ, as one component of the Gangrinboche Group, and was derived from the Xigaze forearc basin, Yarlung-Zangbo suture zone, as well as the Tethyan Himalaya. Furthermore, the Liuqu Conglomerate was exhumed to the surface by post-depositional incision of a tributary of the Yarlung Zangbo river by the Late Miocene time.Aitchison, J. C.; Ali, J. R., and Davis, A. M. 2007, When and where did India and Asia collide?: J. Geophys. Res. v. 112: B05423, doi:10.1029/2006JB004706.Wang, J.G., Hu, X.M., Wu, F.Y., and Jansa, L., 2010, Provenance of the Liuqu Conglomerate in southern Tibet: A Paleogene erosional record of the Himalayan-Tibetan orogen: Sedimentary Geology, v. 231, p. 74-84, doi:10.1016/j.sedgeo.2010.09.004.

  20. Geophysical exploration of an active pockmark field in the Bay of Concarneau, southern Brittany, and implications for resident suspension feeders

    NASA Astrophysics Data System (ADS)

    Baltzer, Agnès; Ehrhold, Axel; Rigolet, Carinne; Souron, Aurélie; Cordier, Céline; Clouet, Hélène; Dubois, Stanislas F.

    2014-06-01

    About a decade ago, a large field of pockmarks (individual features up to 30 m in diameter and <2 m deep) was discovered in water depths of 15-40 m in the Bay of Concarneau in southern Brittany along the French Atlantic coast, covering an overall area of 36 km2 and characterised by unusually high pockmark densities in places reaching 2,500 per square kilometre. As revealed by geophysical swath and subbottom profile data ground-truthed by sediment cores collected during two campaigns in 2005 and 2009, the confines of the pockmark field show a spectacular spatial association with those of a vast expanse of tube mats formed by a benthic community of the suspension-feeding amphipod Haploops nirae. The present study complements those findings with subbottom chirp profiles, seabed sonar imagery and ultrasonic backscatter data from the water column acquired in April 2011. Results show that pockmark distribution is influenced by the thickness of Holocene deposits covering an Oligocene palaeo-valley system. Two groups of pockmarks were identified: (1) a group of large (>10 m diameter), more widely scattered pockmarks deeply rooted (up to 8 ms two-way travel time, TWTT) in the Holocene palaeo-valley infills, and (2) a group of smaller, more densely spaced pockmarks shallowly rooted (up to 2 ms TWTT) in interfluve deposits. Pockmark pore water analyses revealed high methane concentrations peaking at ca. 400 μl/l at 22 and 30 cm core depth in silty sediments immediately above Haploops-bearing layers. Water column data indicate acoustic plumes above pockmarks, implying ongoing pockmark activity. Pockmark gas and/or fluid expulsion resulting in increased turbidity (resuspension of, amongst others, freshly settled phytoplankton) could at least partly account for the strong spatial association with the phytoplankton-feeding H. nirae in the Bay of Concarneau, exacerbating impacts of anthropogenically induced eutrophication and growing offshore trawling activities. Tidally driven hydraulic pumping in gas-charged pockmarks represents a good candidate as large-scale short-term triggering mechanism of pockmark activation, in addition to episodic regional seismic activity.

  1. Average Stress Drops of Southern California Earthquakes in the Context of Crustal Geophysics: Implications for Fault Zone Healing

    NASA Astrophysics Data System (ADS)

    Hauksson, Egill

    2015-05-01

    To understand how fault healing processes affect earthquake stress drops, we search for a possible dependency of stress drops on crustal conditions and geophysical parameters. We reanalyze the stress drop values of ~60,000 earthquakes in southern California which were originally determined by Shearer et al. J Geophys Res 111:B06303, (2006) using a spectral method. We modify the dataset to include only stress drops that are derived from at least 10 spectra and with corner frequencies between 3 and 30 Hz, and correct the rupture velocity for increasing S-wave speed with depth. We see no dependence of stress drop on moment magnitude or depth, except for a small, poorly determined increase from 15 to 25 km. We use six crustal geophysics parameters to search for obvious correlations that may explain changes in the mean values of the stress drops: (1) crustal thickness, (2) isostatic gravity, (3) heat flow, (4) shear strain rate, (5) crustal stress regime, and (6) style of faulting. None of the variables reduce the scatter but most can explain up to 10-20 % variations in the mean stress drops. The geographical distribution of the grouped mean stress drops includes very high stress drops near Ridgecrest, eastern California, as well as near fault jogs within the San Andreas Fault system. Low stress drops dominate in trans-tensional regions. Heat flow and GPS-based shear strain rate estimates have the largest influence on stress drop variations. In the range of low to medium heat flow, the stress drops increase with increasing heat flow. In contrast, at high heat flow in thin crust, the stress drops decrease systematically with increasing heat flow. Increasing shear strain rate systematically correlates with decreasing stress drops. The crustal stress regime and style of faulting also influence the stress drops as demonstrated by lower stress drops for north-northeast trending principal horizontal stress and in areas of dip-slip faulting. The mean variations in stress drops with heat flow, stress regime, crustal thickness, and density can be explained in the context of fault healing (grain boundary growth) and corresponding increase in fault zone strength on time scales modulated by the tectonic shear strain rate.

  2. Origin of the Lyme Dome and implications for the timing of multiple Alleghanian deformational and intrusive events in southern Connecticut

    USGS Publications Warehouse

    Walsh, G.J.; Aleinikoff, J.N.; Wintsch, R.P.

    2007-01-01

    Geologic mapping, structural analysis, and geochronology in the area of the Lyme dome, southern Connecticut provides constraints on the origin of the rocks in the core of the dome, the absolute timing of the principal deformational and thermal events attributed to Alleghanian orogenesis, and the processes that generated the dome. Detrital zircon geochronology in combination with ages on intrusive rocks brackets the deposition of quartzite in the core of the dome sometime between ca. 925 and 620 Ma. Granite and granodiorite intruded the Neoproteorozic metasedimentary rocks in the core of the dome at ca. 620 to 610 Ma. Four major early Permian events associated with the Alleghanian orogeny affected the rocks in the Lyme dome area. Syn-tectonic migmatization and widespread penetrative deformation (D1, ca. 300 - 290 Ma) included emplacement of alaskite at 290 ?? 4 Ma during regional foliation development and aluminosilicate-orthoclase metamorphic conditions. Rocks of the Avalon terrane may have wedged between Gander cover rocks and Gander basement in the core of the Lyme during D1. Limited structural evidence for diapiric uplift of the Lyme dome indicates that diapirism started late in D1 and was completed by D2 (ca. 290 - 280 Ma) when horizontal WNW contractional stresses dominated over vertical stresses. Second sillimanite metamorphism continued and syn-tectonic D2 granite pegmatite (288 ?? 4 Ma) and the Joshua Rock Granite Gniess (284 ?? 3 Ma) intruded at this time. North-northwest extension during D3 (ca. 280 - 275 Ma) led to granitic pegmatite intrusion along S3 cleavage planes and in extensional zones in boudin necks during hydraulic failure and decompression melting. Intrusion of a Westerly Granite dike at 275 ?? 4 Ma suggests that D3 extension was active, and perhaps concluding, by ca. 275 Ma. Late randomly oriented but gently dipping pegmatite dikes record a final stage of intrusion during D4 (ca. 275 - 260 Ma), and a switch from NNW extension to vertical unloading and exhumation. Monazite and metamorphic zircon rim ages record this event at ca. 259 Ma. The evolution of the Lyme dome involved D1 mylonitization, intrusion, and migmatization during north-directed contraction, limited late D1 diapirism, D2 migmatization during WNW contraction with associated flexural flow and fold interference, D3 NNW horizontal extension and decompression melting, and final D4 vertical extension and rapid exhumation. Late regional uplift, extension, and normal faulting at higher crustal levels may have been caused by diapiric rise of the lower crust, below the structural level of the Lyme dome. The rocks record no evidence of Acadian metamorphism or deformation, suggesting that the Gander zone here was not tectonically juxtaposed with Avalon until the Alleghanian orogeny.

  3. Hypertension among Rural Population in Four States: Sudan 2012

    PubMed Central

    Balla, Siham Ahmed; Abdalla, Asma Abdelaal; Elmukashfi, Taha Ahmed; Ahmed, Haiedr Abu

    2014-01-01

    Background: Hypertension is emerging as an alarming public-health problem causes organ damage. Objectives: To identify prevalence of hypertension and predictor factors among rural population in four states in Sudan. Methods: A community based cross-sectional study was conducted in sixteen rural areas in Sudan during April 2012. A total of 3020 adult were interviewed using structured questionnaire and blood pressure was measured before and after the interview. Hypertension was taken as ≥ 140 mmHg and ≥ 90 mmHg for systole and diastole respectively. Analysis: Descriptive statistic was presented; Sex and mean of systolic and diastolic blood pressure were tested using ANOVA for individuals on antihypertensive medication. Predictor factors to hypertension were tested by logistic regression. Results: Prevalence of hypertension among rural population was 15.8%. Overall means of systolic and diastolic blood pressure were 128.6±17.7 and 81.5±11.6 respectively while the means among hypertensive individuals was154.74 ±14.4 and 97.98±8.4 respectively Known hypertensive individuals were 20.1%; out of whom 71.7% were hypertensive and 22.4% have Target Organ Damage. Those on anti-hypertensive medications were 76.4% and normotensive were 55.1%. Individuals having both diabetes and hypertension were 3.3% and 80.2% were hypertensive. Log regression model showed age, smoking, diabetes and family hypertension were predictors of hypertension by 3.6%, 34.9%, 49.7% and 56.8% respectively (P-value <0.05). Conclusion: Prevalence of hypertension among rural Sudan was 15.8%. Family history was the strongest predictor of hypertension. PMID:24762364

  4. Environmental determinants of the distribution of Phlebotomus orientalis in Sudan.

    PubMed

    Elnaiem, D A; Connor, S J; Thomson, M C; Hassan, M M; Hassan, H K; Aboud, M A; Ashford, R W

    1998-12-01

    Despite its importance as a vector of visceral leishmaniasis in Sudan, the ecology of Phlebotomus orientalis is still poorly understood. The results of a ground-based survey and a geographical-information-system (GIS) study, carried out to investigate the environmental determinants of the distribution of P. orientalis in the wooded areas of the central savannah belt of Sudan, are described here. The survey, carried out in April-June 1996, consisted of a collection of sandflies over two consecutive nights at each of 44 study sites, using three CDC, miniature, light traps at each site. During the survey, the ecology of each site was described. Phlebotomus orientalis was caught at 17 of the sites. Environmental data on the collection sites (rainfall, minimum and maximum temperatures, soil class, vegetation and land-surface-temperature indices) were extracted from a range of sources of digital data collected by satellites in the National Ocean and Atmospheric Administration's series. These data were then analysed, to ascertain which variables were significantly associated with sites positive for P. orientalis. In line with the results of previous studies, P. orientalis was found to have a significant association with the presence of the tree species Acacia seyal and Balanites aegyptiaca and with the black cotton (vertisolic) soils of eastern Sudan. The positive sites were found to have significantly higher annual mean maximum and minimum daily temperatures than the negative sites and the annual mean maximum normalized-difference vegetation index (NDVI) value was also found to be significantly higher in these sites than in sites where no P. orientalis were found. PMID:10396348

  5. Tectono-thermal History of the Southern Nenana Basin, Interior Alaska: Implications for Conventional and Unconventional Hydrocarbon Exploration

    NASA Astrophysics Data System (ADS)

    Dixit, N. C.; Hanks, C. L.

    2014-12-01

    The Tertiary Nenana basin of Interior Alaska is currently the focus of both new oil exploration and coalbed methane exploitation and is being evaluated as a potential CO2sequestration site. The basin first formed as a Late Paleocene extensional rift with the deposition of oil and gas-prone, coal-bearing non-marine sediments with excellent source potential. Basin inversion during the Early Eocene-Early Oligocene times resulted in folding and erosion of higher stratigraphic levels, forming excellent structural and stratigraphic traps. Initiation of active faulting on its eastern margin in the middle Oligocene caused slow tectonic subsidence that resulted in the deposition of reservoir and seal rocks of the Usibelli Group. Onset of rapid tectonic subsidence in Pliocene that continues to the present-day has provided significant pressure and temperature gradient for the source rocks. Apatite fission-track and vitrinite reflectance data reveals two major paleo-thermal episodes: Late Paleocene to Early Eocene (60 Ma to 54.8 Ma) and Late Miocene to present-day (7 Ma to present). These episodes of maximum paleotemperatures have implications for the evolution of source rock maturity within the basin. In this study, we are also investigating the potential for coalbed methane production from the Late Paleocene coals via injection of CO2. Our preliminary analyses demonstrate that 150 MMSCF of methane could be produced while 33000 tonnes of CO2 per injection well (base case of ~9 years) can be sequestered in the vicinity of existing infrastructure. However, these volumes of sequestered CO2and coal bed methane recovery are estimates and are sensitive to the reservoir's geomechanical and flow properties. Keywords: extensional rift, seismic, subsidence, thermal history, fission track, vitrinite reflectance, coal bed methane, Nenana basin, CO2 sequestration

  6. Minerals and trace elements in silcretes of the Sado basin (Alentejo, southern Portugal) and implications for silcrete formation

    NASA Astrophysics Data System (ADS)

    Sauer, Daniela; Kullmann, Sarah; Zarei, Mehdi; Stahr, Karl

    2014-05-01

    Soils in the eastern part of the Sado basin (southern Portugal) are often characterized by massive cementations caused by silica. The thickness and massive character of these silcretes led to the hypothesis that accumulation of silica took place not only vertically within a soil profile, but also by enrichment through lateral water and element flow into the Sado basin. The aims of the study reported here were: 1) to characterize the cementing agent with regard to its mineralogy; 2) to test the hypothesis that silification was enhanced through lateral silica transport from the adjacent Alto Alentejo into the Sado basin. Aim 1) was achieved by scratching silica coatings from ped surfaces of the silicified soil horizons and cleaning them manually in the lab under a binocular microscope. After careful smashing with a mortar, density separation by sodium polytungstate solution was applied to remove any remaining mineral grains from the silica samples. The cleaned silica samples were then subjected to XRD and SEM in combination with EDS. Aim 2) was attained by using trace element contents of predominant rock types of the Alto Alentejo and of the silcretes in the Sado basin for identifying lateral pathways of water and silica in the landscape. Ten rock samples from the assumed source area of silica were combusted by fusion melt, and their contents of Ba, Co, Cs, Nb, Pb, Rb, Sr, Y and Zr were analyzed by ICP-MS. The same elements were analyzed in NaOH extracts of the cemented soil horizons in the Sado basin. The X-ray diagrams of the silica coatings show the expected broad hump of amorphous silica. In addition, quartz, kaolinite, and surprisingly high amounts of halloysite are identified, the latter reflecting conditions of intensive weathering and pedogenesis during the formation of the silica coatings. This intensive soil formation and hence silification most likely took place during Pliocene. Greater age is impossible, because the silification took place in Pliocene sediments; later, on the other hand, the climate became cooler, hence intensity of pedogenesis should have decreased. It is assumed that halloysite was preserved over such long period of time, because it was occluded in the silica mass. The micromorphology of the coatings under the SEM includes laminar coverings, banded and alveolar structures. EDS analysis shows that the coatings consist mainly of silicon; in addition they contain aluminum and some also have minor amounts of iron. Trace element contents of the rock samples and silcretes enabled tracing lateral silica flows from the Alto Alentejo into the Sado basin. Some rock samples and silcretes contained considerable amounts of Barium. Even barite crystals were observed in the silica coatings under the SEM. Acknowledgement The authors thank Beate Podtschaske for her valuable help in the laboratory and the German Research Foundation DFG for financial support (project STA 146/45-3).

  7. Cooling History in Mabja Dome, Southern Tibet: Implications for the Tectonic Evolution of the North Himalayan Gneiss Domes

    NASA Astrophysics Data System (ADS)

    Lee, J.; Wang, Y.; McWilliams, M.; Hourigan, J.; Blythe, A.; McClelland, W.

    2001-12-01

    The Mabja Dome (MD), southern Tibet, is one of a series of gneiss domes, called the North Himalayan Gneiss Domes, located south of the Indus-Tsangpo suture zone and north of the high Himalaya. The MD consists of an ~25 km diameter doubly plunging antiform cored by migmatitic K-feldspar augen biotite orthogneiss which is mantled by high grade metapelites and granitic orthogneisses. These rocks record two primary deformational events: an older deformational event, D1, characterized by ~EW-trending folds of S0 with an associated moderately N-dipping axial planar foliation, S1, and a younger event, D2, characterized by a domed mylonitic foliation, S2, and associated NS-trending mineral stretching lineation. Peak metamorphism is pre- to early syntectonic with D2 structures and defines a set of isograds that are subparallel to structure. Two-mica granites, one of which yielded an U/Pb monazite age of 14.5+/-0.1 Ma, were emplaced during the latest stages of D2 deformation. Mica and kspar Ar/Ar and apatite fission track (AFT) analyses were completed on orthogneisses, metasediments, and two-mica granites to shed light on the timing and mechanism of cooling of these rocks. Muscovite yielded Ar/Ar cooling ages of ~12.7 Ma on the northern flank of the dome, increasing to ~17.0 Ma in metapelite and orthogneiss at deeper structural levels, and decreasing to ~13.5 Ma within migmatite at the deepest structural levels. Biotites are disturbed and yield total gas ages that are slightly younger than muscovite on the flanks of the dome, but older within the core. Analyses of four kspars from orthogneiss and migmatite yielded complex spectra with old apparent ages at the lowest temperature steps, followed by ages that climb slowly from 12.5-13.0 Ma over the first 30% of 39Ar released, which in turn is followed by ages that climb to 100 Ma (orthogneiss) and 15-18 Ma (migmatite) at high temperature steps. AFT analyses from orthogneiss and migmatite yielded a mean age of 9.5 Ma indicating symmetric cooling across the dome at this time. The two mica granites yielded concordant muscovite and biotite ages of 13.1-13.5 Ma, ages of ~11 Ma at the low temperature part of kspar spectra and ages of ~13 Ma at the high temperature part, and AFT ages of 9.2-9.9 Ma. Cooling rates vary from ~60° C/Ma in the migmatitic core and two-mica granites to ~30° C/Ma in the overlying metapelite and orthogneiss. We interpret these structural, metamorphic, and cooling relations as suggesting a similar tectonic history as that documented in the Kangmar Dome (e.g. Lee et al., 2000): (1) contraction (D1 deformation) leading to thickening followed by thermal re-equilibration (peak metamorphism), (2) mid-crustal extension (D2 deformation), (3) doming and exhumation as a consequence of thrusting upward and southward over a north-dipping ramp above cold Tethyan sediments (mica Ar/Ar ages at higher structural levels that increase with depth suggesting refrigeration from below) and erosion during early to middle Miocene, and (4) emplacement of two-mica granites resulting in reheating at the deepest structural levels during the middle Miocene and continued doming as a consequence of diapirism and erosion during middle to late Miocene.

  8. Paleoclimatic implications (Late Cretaceous-Paleogene) from micromorphology of calcretes, palustrine limestones and silcretes, southern Paraná Basin, Uruguay

    NASA Astrophysics Data System (ADS)

    Tófalo, Ofelia R.; Pazos, Pablo J.

    2010-04-01

    Sedimentologic and petrographic analyses of outcroping and subsurface calcretes, palustrine carbonates, and silcretes were carried out in the southern Paraná Basin (Uruguay). The aim of this work is to describe the microfabric and interpret the genesis of these rocks through detailed analyses, since they contain significant paleoenvironmental and paleoclimatic evolution information. The main calcrete and silcrete host rock (Mercedes Formation) is represented by a fluvial thinning upward succession of conglomerate and sandstone deposits, with isolated pelitic intervals and paleosoils. Most of the studied calcretes are macroscopically massive with micromorphological features of alpha fabric, originated by displacive growth of calcite in the host clastic material due to evaporation, evapotranspiration and degassing. Micromorphologically, calcretes indicate an origin in the vadose and phreatic diagenetic environments. Micrite is the principal component, and speaks of rapid precipitation in the vadose zone from supersaturated solutions. The abundance of microsparite and secondary sparite is regarded as the result of dissolution and reprecipitation processes. Although present, brecciated calcretes are less common. They are frequent in vadose diagenetic environments, where the alternation between cementation and non-tectonic fracturing conditions take place. These processes generated episodes of fragmentation, brecciation and cementation. Fissures are filled with clear primary sparitic calcite, formed by precipitation of extremely supersaturated solutions in a phreatic diagenetic environment. The micromorphological characteristics indicate that calcretes resulted from carbonate precipitation in the upper part of the groundwater table and the vadose zone, continuously nourished by lateral migration of groundwater. The scarcity of biogenic structures suggests that they were either formed in zones of little biological activity or that the overimposed processes related to water table fluctuations produced intense recrystallization completely obliterating the biogenic fabric. Limestone beds containing terrestrial gastropods are geographically restricted. Situated at the top of the calcrete successions, they exhibit brecciated and peloidal-intraclastic textures but lack lamination, edaphic structures, aggregates and vertical rhizoliths. This indicates they correspond to low-energy palustrine deposits, generated in shallow, local and ephemeral ponds developed in topographic depressions. When water table levels dropped, the palustrine deposits were exposed. This favours the presence of terrestrial gastropods, seeds and insect nests. The combination of calcretes and palustrine carbonates indicates periods and areas with a reduced clastic input and a predominantly semiarid climate, with well-defined humid and dry seasons. Characteristics of the later developed massive and nodular horizons of silcretes, such as, preservation of the internal structure of the host rock, the small areal extent, the formation of massive lenses, the complex pore infillings and the lack of a columnar upper section, indicate that they were generated from groundwaters. Every silcretized horizon shows different positions of the groundwater table and relates to the dissection of landscape. The age of calcretization and silcretization is bracketed between the Late Cretaceous (Campanian-Maastrichtian) and the Early Eocene. Paleoclimate indicates changing conditions from warm and humid at the end of the Cretaceous (Mercedes Formation) to semiarid and seasonal during Paleocene (groundwater calcretes and palustrine deposits) and subtropical and seasonal in the early Eocene (Asencio Formation).

  9. Large Glacitectonic structures on the Dogger Bank, southern North Sea; Implications for glacial dynamics, glacial limits, and interplay between the British and Fennoscandinavian Ice Sheets

    NASA Astrophysics Data System (ADS)

    Dove, Dayton; Cotterill, Carol; Long, Dave; Ruiter, Astrid; Phillips, Emrys; James, Leo; Forsberg, Carl Fredrik

    2013-04-01

    Recently acquired 2D seismic data (sparker) acquired over the Dogger Bank (DB) reveal large glacitectonic structures associated with late-Pleistocene glacial incursion into the southern North Sea. The densely populated survey data (100m line spacing) collected for the purposes of offshore windfarm development on the DB, allow for pseudo-3D interpretation. The sparker data show discrete thrust faults extending from within ~5 m of the seabed to ~200 m depth, and consistently terminate at one of two décollement surfaces. Preliminary mapping and amplitude extraction maps reveal the thrusts to occur in a series of thrust blocks (5-8 faults), with each set encompassing an area of approximately 6 km along-strike and 2 km at right angles. The overall zone of thrusting is up to 16 x 6 km on the western edge of the DB. The strike of the faults indicates ice-flow from the west. Other deformation structures include: open, recumbent, and fault propagation folds, as well as back thrusts, and pop-up structures. The relief of the DB (dimensions) is entirely accounted for by what has historically been termed the 'DB Formation'. These new data reveal that this seismostratigraphic unit likely consists of deposits from a variety of glacially influenced depositional regimes. The observed thrusts penetrate through the 'DB formation', indicating this phase of intense deformation post-dated the initial construction of the bank. Less pronounced glacial deformation affects much of the rest of the DB, and the products of this deformation (push-moraine complexes?) were possibly integral to the construction of the bank itself. While the style and fabric (NS?) of this deformation is less clear, it is likely there were multiple incursions of glacial ice, from different directions (and sources?), into this area where late-Pleistocene glaciation limits are poorly understood. Several mechanisms for forming such glacitectonic features have been proposed, and the thrust blocks here may have been caused by sub-glacial (gravitational spreading), ice-marginal (push-moraine complex), or pro-glacial (ice-push) processes, or a combination of the three at an oscillating ice-margin. The thrusts appear to have no surface expression, suggesting the topography was removed either by late-stage glacial erosion or Holocene marine transgression. Work to date on the paleoenvironmental implications of the data has been preliminary. The exact style, pattern, and timing glacial deformation (and associated sedimentation) on the Dogger Bank and circum-southern North Sea, and glacial history of the region, will be the focus of a Ph.D studentship which commenced Sept. 2012.

  10. Emergency measles control activities--Darfur, Sudan, 2004.

    PubMed

    2004-10-01

    The Darfur region of Sudan, composed of three states with a population of approximately six million, has experienced civil conflict during the previous year, resulting in the internal displacement of approximately one million residents and an exodus of an estimated 170,000 persons to neighboring Chad. The conflict has left a vulnerable population with limited access to food, health care, and other basic necessities. In addition, measles vaccination coverage has been adversely affected; in 2003, coverage was reported to be 46%, 57%, and 77% in North, West, and South Darfur, respectively. This report describes measles-control activities in Darfur region conducted by the Federal Ministry of Health (FMOH) in Sudan in collaboration with the United Nations and nongovernmental organizations (NGOs) during March-August 2004. Ongoing measles transmission in camps for internally displaced persons (IDPs) and neighboring communities in Darfur led to a regionwide measles vaccination campaign targeting all children aged 9 months-15 years, resulting in a reduction in reported measles cases. Once security is improved, ongoing efforts to increase measles vaccine coverage will be required to eliminate persistent susceptibility to measles in the Darfur population. PMID:15457146

  11. A climate distribution model of malaria transmission in Sudan.

    PubMed

    Musa, Mohammed I; Shohaimi, Shamarina; Hashim, Nor R; Krishnarajah, Isthrinayagy

    2012-11-01

    Malaria remains a major health problem in Sudan. With a population exceeding 39 million, there are around 7.5 million cases and 35,000 deaths every year. The predicted distribution of malaria derived from climate factors such as maximum and minimum temperatures, rainfall and relative humidity was compared with the actual number of malaria cases in Sudan for the period 2004 to 2010. The predictive calculations were done by fuzzy logic suitability (FLS) applied to the numerical distribution of malaria transmission based on the life cycle characteristics of the Anopheles mosquito accounting for the impact of climate factors on malaria transmission. This information is visualized as a series of maps (presented in video format) using a geographical information systems (GIS) approach. The climate factors were found to be suitable for malaria transmission in the period of May to October, whereas the actual case rates of malaria were high from June to November indicating a positive correlation. While comparisons between the prediction model for June and the case rate model for July did not show a high degree of association (18%), the results later in the year were better, reaching the highest level (55%) for October prediction and November case rate. PMID:23242678

  12. Low Seroprevalence Indicates Vulnerability of Eastern and Central Sudan to Infection with Chikungunya Virus.

    PubMed

    Adam, Awadalkareem; Seidahmed, Osama M E; Weber, Christopher; Schnierle, Barbara; Schmidt-Chanasit, Jonas; Reiche, Sven; Jassoy, Christian

    2016-04-01

    Outbreaks of infections with chikungunya virus (CHIKV) have previously been reported from Sudan but the prevalence in the general population is unknown. We investigated the seroprevalence of CHIKV infection in 379 serum samples from patients with fever in the outpatient clinics of three hospitals in eastern and central Sudan. The seroprevalence was 1.8%, indicating that CHIKV infections are rare in these parts of Sudan. As the vector Aedes aegypti is endemic in this area, the population is at risk for a CHIKV epidemic. PMID:26974266

  13. Staining histological lung sections with Sudan Black B or Sudan III for automated identification of alveolar epithelial type II cells.

    PubMed

    Schneider, Jan Philipp; Pedersen, Lars; Mühlfeld, Christian; Ochs, Matthias

    2015-10-01

    Alveolar epithelial type II (AE2) cells produce, store and secrete pulmonary surfactant and serve as progenitor cells for the alveolar epithelium. They are thus an interesting target in wide fields of pulmonary research. Stereological methods allow their quantification based on measurements on histological sections. A proper AE2 cell quantification, however, requires a method of tissue processing that results in little tissue shrinkage during processing. It was recently shown that a primary fixation with a mixture of glutaraldehyde and formaldehyde, postfixation with osmium tetroxide and uranyl acetate and embedding in glycol methacrylate fulfills this requirement. However, a proper quantification, furthermore, requires a secure identification of the cells under the microscope. Classical approaches using routine stainings, high magnifications and systematic uniform random sampling can result in a tedious counting procedure. In this article we show that Sudan Black B and Sudan III staining in combination with the previously described "low shrinkage method" of tissue processing result in good staining of lamellar bodies of AE2 cells (their storing organelles of surfactant) and thus provide a good signal of AE2 cells, which allows their easy and secure identification even at rather low magnifications. We further show that this signal enables automated detection of AE2 cells by image analysis, which should make this method a suitable staining method for the recently developed and more efficient proportionator sampling. PMID:26558990

  14. Synsedimentary deformation of Pleistocene glaciolacustrine deposits in the Albese con Cassano Area (Southern Alps, Northern Italy), and possible implications for paleoseismicity

    NASA Astrophysics Data System (ADS)

    Chunga, Kervin; Livio, Franz; Michetti, Alessandro M.; Serva, Leonello

    2007-03-01

    We describe and interpret the well exposed soft-sediment deformations preserved in a Mid-Pleistocene proglacial sequence outcropping at Albese con Cassano, near Como (Southern Alps, N Italy). The observed deformations affect six distinct stratigraphic intervals within the same depositional sequence. The stratigraphy of this sequence, the geomorphic setting, and the careful geological mapping of the area clearly show that these deformations are not the result of glaciotectonics or cryoturbation, but are due to six separate events of synsedimentary liquefaction. In particular, the 3 basal deformed units include sand and gravel volcanoes that formed at the bottom of a proglacial lake. We examined several hypothesis of possible causative mechanism for the formation of these features. Taking into account all the information available on the local geology and sedimentary environment, it is possible to assess that the liquefaction features at Albese con Cassano had a coseismic origin. To our knowledge, this would be the first report of similar evidence of paleoseismicity in the Lombardia Southern Alps. Also, there is no record of historical liquefaction triggered by seismic events in an area of ca. 70 km of radius near Albese con Cassano, including the town of Como, the large metropolitan area of Milano and most of W Lombardia, that is one of the largest industrial districts in Europe. Therefore, the interpretation of the observed deformations can have critical impact for understanding the current seismicity level in the region, and mitigating the associated risk. In this paper we show that this interpretation is not a simple process. Liquefaction features must be treated with caution in order to derive suitable information for seismic hazard characterization, even if their coseismic origin has been definitely proved. It is necessary to understand the amount of seismic shaking (for instance, in terms of local macroseismic intensity) that can have produced that specific feature at that specific site, the location of the causative seismic event (epicenter and focal depth), and eventually its size (in terms of epicentral intensity and/or earthquake magnitude). In the case of Albese con Cassano, the implications in terms of seismic hazard of the observed possible earthquake paleoliquefactions can only be assessed through the definition of several scenarios, taking into account: a) different thresholds of shaking for triggering the described synsedimentary structures, and b) different seismotectonic frameworks related to the Mid-Pleistocene to Holocene evolution of the S Alps, including seismicity induced by isostatic glacial rebound. We conclude that it is worth checking these scenarios in the field with further paleoseismological research on other possible evidence of past earthquakes. There are no unequivocal sedimentological indicators of paleoseismicity, however, when carefully interpreted within the proper local seismotectonic context and compared with other earthquake-induced features, soft-sediment deformations can offer information of critical value for seismic hazard assessment.

  15. Peste des petits ruminants outbreaks in White Nile State, Sudan.

    PubMed

    Ishag, Osama M; Saeed, Intisar K; Ali, Yahia H

    2015-01-01

    Eight outbreaks of peste des petits ruminants in sheep and goats were reported in White Nile State, Sudan, between 2008 and 2009. A mortality rate of 4.2% was reported across the different outbreaks. Clinically the disease was characterised by high fever, ocular and nasal discharge, pneumonia, ulceration of the mucous membranes, diarrhoea and death. The postmortem findings included necrotic lesions in the mouth and gastrointestinal tract, and swollen, oedematous lymph nodes associated with the lungs and intestine. Of the 209 serum samples tested by competitive enzyme-linked immunosorbent assay, 113 (54%) were found positive. Peste des petits ruminants virus was confirmed in tissues, nasal swabs and blood samples by immunocapture enzyme-linked immunosorbent assay, reverse-transcription polymerase chain reaction and isolation of the virus in culture of lamb testicle cells. PMID:26304168

  16. Anaerobic Metabolism of 1-Amino-2-Naphthol-Based Azo Dyes (Sudan Dyes) by Human Intestinal Microflora▿

    PubMed Central

    Xu, Haiyan; Heinze, Thomas M.; Chen, Siwei; Cerniglia, Carl E.; Chen, Huizhong

    2007-01-01

    The rates of metabolism of Sudan I and II and Para Red by human intestinal microflora were high compared to those of Sudan III and IV under anaerobic conditions. Metabolites of the dyes were identified as aniline, 2,4-dimethylaniline, o-toluidine, and 4-nitroaniline through high-performance liquid chromatography and liquid chromatography electrospray ionization tandem mass spectrometry analyses. These data indicate that human intestinal bacteria are able to reduce Sudan dyes to form potentially carcinogenic aromatic amines. PMID:17933925

  17. The Impact of Conflict on Forests in South Sudan

    NASA Astrophysics Data System (ADS)

    Gorsevski, V.; Kasischke, E. S.; Dempewolf, J.; Loboda, T. V.; Geores, M.

    2014-12-01

    The impacts of armed conflict on ecosystems are complex and difficult to assess due to restricted access to affected areas making satellite remote sensing a useful tool for studying direct and indirect effects of conflict on the landscape. The Imatong Central Forest Reserve (ICFR) in South Sudan together with the nearby Dongotana Hills and the Agoro-Agu Forest Reserve (AFR) in Northern Uganda share a boundary and encompass a biologically diverse montane ecosystem. This study used satellite data combined with general human population trends to examine the impact of armed conflict and its outcome on similar forest ecosystems both during and after hostilities. A Disturbance Index (DI) was used to investigate the location and extent of forest cover loss and gain in three areas for two key time periods. Results indicate that the rate of forest recovery was significantly higher than the rate of disturbance both during and after wartime in and around the ICFR. In contrast, the nearby Dongotana Hills experienced relatively high rates of disturbance during both periods; however, post war period losses were largely offset by some gains in forest cover. Discussions with local inhabitants confirmed these findings and provided further insights into the underlying causes impacting forest cover and wildlife. South Sudan is the latest nation to join the Global Environment Facility (GEF). While the GEF does not explicitly address conflict, many of the projects it supports occur in conflict and post-conflict zones with wide-ranging repercussions for both people and the environment. In an effort to assess best practices for working in conflict and post-conflict areas, the GEF Scientific and Technical Advisory Panel (STAP) will undertake an analysis of GEF-funded projects over the last two decades to identify where the GEF has promoted cooperation between groups and states, and/or made a positive contribution toward conflict avoidance resulting in shared environmental benefits.

  18. First report of Neospora caninum infection in cattle in Sudan.

    PubMed

    Ibrahim, Amira Mohamed Elhassan; Elfahal, Abdelghafar Mohamed; El Hussein, Abdel Rahim Mohamed

    2012-04-01

    A cross-sectional survey was conducted in Sudan to determine sero-prevalence and risk factors associated with Neospora caninum infection in non-vaccinated dairy herds and to assess importance of the disease. Blood samples were collected from a total of 262 animals from 25 herds. Sera were tested for antibodies against N. caninum using ELISA test. The prevalence rates of N. caninum antibodies in cattle were high both at herd level (44%) and at individual animal level (10.7%). Herd level infection rates were similar in Khartoum State (43.7%) and at Gazira States (44.4%). The overall prevalence rates were higher (16.1%) in Gazira State than in Khartoum State (9%) but with no significant variation. The sero-prevalence at individual animal level was significantly higher (p < 0.05) in animals with history of abortion (12.8%) than in apparently healthy animal (11.3%), animal with history of infertility (8.1%), or neonatal death of calves (4.3%). In addition, significantly higher (P < 0.05) sero-prevalence was observed in samples collected during the rainy season (6.87%) than winter (3.05%) or summer (0.76%). However, no significant differences in sero-prevalence due to locality, animal breed, sex, and age were observed (p > 0.05). This preliminary study reveals for the first time the existence of natural N. caninum infection in Sudan. Also, the findings of the present study indicated that this disease is highly prevalent in two major areas of dairy production in the country, and this calls for control strategy to be implemented. PMID:21898183

  19. Elasticity of demand for water in Khartoum, Sudan.

    PubMed

    Cairncross, S; Kinnear, J

    1992-01-01

    A survey of the quantities of water purchased from vendors in the squatter areas of Khartoum, Sudan, was used to assess the effect of the price charged for water and of household income on domestic water consumption. Households in two squatter communities--Meiyo and Karton Kassala--were studied by observation and by interview. In spite of the substantially higher charges, water consumption in Karton Kassala was as high as that in Meiyo. Households within these communities showed no tendency to use less water when paying a higher price for it, or when their income was below average. In other words, no price elasticity or income elasticity was detectable. This was all the more striking in view of the high proportion of income that was spent on water; 17% in Meiyo, and 56% in Karton Kassala. One consequence of this lack of elasticity is that the poorest households devote the greatest percentage of their income to the purchase of water, although the only major item in their household budget which can be sacrificed to make this possible is food. The high price of water in urban Sudan is probably a major cause of the malnutrition prevalent in the squatter areas. Another consequence is that a low-income household's consumer surplus for domestic water is very high, amounting to a substantial proportion of its total income. This has important consequences for the economic appraisal of urban water supply schemes. It also follows that wealthier households with private connections would be willing to pay at least as much for water as that currently paid by the poor. PMID:1738871

  20. a Regional Study of Seasonal Rainfall Conditions in the Sudan

    NASA Astrophysics Data System (ADS)

    El Seed, Abdel Malik Gasm

    Available from UMI in association with The British Library. This thesis is primarily a regional climatological study of some spatial and temporal rainfall characteristics, with a special emphasis being made on quantitative analysis of the wet season rains over the Sudan. The study area has been objectively classified into five main "rainfall regions" on the basis of wet season duration and timing at 60 observing stations. Also a regionalisation derived from two multivariate techniques is compared and critically discussed. The spatial distributions of mean wet and dry season rainfall over individual regions, are described and explained by reference to the main weather systems and topographic features using the method of trend surface analysis. Rainfall variability has been quantified by the coefficient of variation index and analysed in a similar way to that of rainfall distribution. The results have shown an inverse relationship between variability indices and mean rainfall amounts. In relation to the study of variability, an assessment of rainfall probability and reliability has been discussed with reference to certain critical rainfall amounts and by applying the concept of binomial frequency distribution for critical time periods. The spatial distribution of mean rain days tends to portray a similar pattern to that of the mean rainfall. This apparent relationship is confirmed by the highly significant correlation coefficients between the two parameters. The relation between mean rainfall and daily rainfall intensity is not always a direct one, since wetter areas are mostly associated with increased frequency of rain days rather than greater rainfall intensities. Daily rainfall analysis has also revealed that the probability distributions of wet and dry spells of various sequence lengths can be mathematically derived from a Markov chain model and these were found to fit the actual daily data closely. Finally, the contributions of various atmospheric factors to the rainfall amounts are determined by applying multiple regression analysis. The provision of partial regression equations also permits an estimate of rainfall with a reasonable degree of accuracy for any place in the Sudan.

  1. 78 FR 68500 - In the Matter of the Designation of Jama'atu Ansarul Muslimina Fi Biladis-Sudan Also Known as...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-14

    ... Africa Also Known as JAMBS Also Known as Jama'atu Ansaril Muslimina Fi Biladis Sudan as a Specially... Black Africa, also known as JAMBS, also known as Jama'atu Ansaril Muslimina Fi Biladis Sudan,...

  2. Education in Emergencies and Early Reconstruction: UNICEF Interventions in Colombia, Liberia, and Southern Sudan

    ERIC Educational Resources Information Center

    Beleli, Ozsel; Chang, Victoria; Feigelson, Michael J.; Kopel-Bailey, Jules A.; Maak, Sheila A.; Mnookin, Jacob P.; Nguyen, Thu H.; Salazar, Mariana; Sinderbrand, Joy E.; Tafoya, Simon N.

    2007-01-01

    Broad access to quality, child-friendly education in emergencies is a critical component of early reconstruction and development. As a class of graduate students at the Woodrow Wilson School of Public and International Affairs at Princeton University, our goal is to make a modest contribution to the field of education in emergencies by working…

  3. International Aid as Informal Educator: Exploring Political Attitudes and Engagement in Southern Sudan

    ERIC Educational Resources Information Center

    Pagen, Christine Mary

    2010-01-01

    Scholarship has isolated internal economic conditions and political institutions as essential factors in political development and democracy-building, this research suggests that external influences are at play. During times of civil war and post-conflict reconstruction, governmental and socioeconomic structures are likely weak or nonexistent, and…

  4. Guayape-Papalutla fault system: A continuous Cretaceous structure from southern Mexico to the Chortís block? Tectonic implications

    NASA Astrophysics Data System (ADS)

    Silva-Romo, G.

    2008-01-01

    Recent papers have opened the debate over whether the Chortísblock was located off the coast of southern Mexico or in a moreoutboard position, and this led me to explore whether correlationswith older structures could be established to determine theevolution of the southwest corner of the North America plate.In this paper I hypothesize that the Papalutla fault of Mexicoand the Guayape fault system of Honduras, both considered tobe terrane boundaries, were roughly continuous in the Cretaceous,extending from southern Mexico to the Chortís block.They influenced Early Cretaceous clastic sedimentation of theZicapa Formation on the Guerrero-Morelos Platform (southernMexico) and the Tepemechin Formation of the Central Chortísterrane (Honduras). The units accumulated in fault-bounded basinsassociated with left-lateral slip. The basins developed in theCentral Chortís terrane and Guerrero-Morelos Platform.Both geological entities appear to represent a continuous Cretaceousgeologic province characterized by a trangression that occurredearlier in Honduras than in southern Mexico. This nonrotationalhypothesis for the location of the Chortís block adjacentto southern Mexico during the Cretaceous is consistent withnortheastward displacement of the Caribbean plate during Cretaceoustime and implies 1500 km of Chortís block displacementduring the Cenozoic.

  5. Leishmaniasis in Sudan. Post kala-azar dermal leishmaniasis.

    PubMed

    Zijlstra, E E; el-Hassan, A M

    2001-04-01

    Post kala-azar dermal leishmaniasis (PKDL) is increasingly recognized in Sudan as a complication of visceral leishmaniasis (VL), occurring in c. 55% of patients after, or during treatment of, VL. The development of PKDL seems to be restricted to parasites of the Leishmania donovani sensu stricto cluster; no particular zymodeme has been found to be associated with it. In contrast to PKDL in India, PKDL in Sudan occurs within 0-6 months after treatment for VL. The rash may be macular, maculo-papular or nodular, and spreads from the perioral area to other parts of the body, depending on grade of severity. Young children are particularly at risk of developing more severe disease. In 16% of PKDL patients, parasites can be demonstrated by microscopy in lymph node or bone marrow aspirates and, with the aid of the polymerase chain reaction (PCR), in lymph nodes of 81% of patients, possibly indicating persistent visceralized infection. Diagnosis can be made by demonstration of parasites in skin smears or biopsies in 20-30% of cases; newer techniques, using PCR with skin smears, have higher sensitivity (83%). Monoclonal antibodies against L. donovani can detect parasites in 88% of biopsies. Serological tests are of limited value. The leishmanin skin test is positive in 50-60% of cases; there is an inverse relationship between the skin test result and severity of PKDL. In differential diagnosis, miliaria rubra is the most common problem; differentiation from leprosy is the most difficult. In biopsies, hyperkeratosis, parakeratosis, acanthosis, follicular plugging and liquefaction degeneration of the basal layer may be found in the epidermis; in the dermis there are varying intensities of inflammation with scanty parasites and mainly lymphocytes; macrophages and epithelioid cells may also be found. In 20% of cases discrete granulomas may be found. After VL, the immune response shifts from a Th2-type to a mixed Th1/Th2-type. High levels of interleukin-10 in skin biopsies as well as in peripheral blood mononuclear cells and plasma in patients with VL predict the development of PKDL. Treatment is needed only for those who have severe and prolonged disease; sodium stibogluconate (20 mg/kg/d for 2 months) is usually sufficient. (Liposomal) amphotericin B is effective, whereas ketoconazole, terbinafine and itraconazole are not. PMID:11370251

  6. Human African Trypanosomiasis in South Sudan: How Can We Prevent a New Epidemic?

    PubMed Central

    Ruiz-Postigo, José A.; Franco, José R.; Lado, Mounir; Simarro, Pere P.

    2012-01-01

    Human African trypanosomiasis (HAT) has been a major public health problem in South Sudan for the last century. Recurrent outbreaks with a repetitive pattern of responding-scaling down activities have been observed. Control measures for outbreak response were reduced when the prevalence decreased and/or socio-political crisis erupted, leading to a new increase in the number of cases. This paper aims to raise international awareness of the threat of another outbreak of sleeping sickness in South Sudan. It is a review of the available data, interventions over time, and current reports on the status of HAT in South Sudan. Since 2006, control interventions and treatments providing services for sleeping sickness have been reduced. Access to HAT diagnosis and treatment has been considerably diminished. The current status of control activities for HAT in South Sudan could lead to a new outbreak of the disease unless 1) the remaining competent personnel are used to train younger staff to resume surveillance and treatment in the centers where HAT activities have stopped, and 2) control of HAT continues to be given priority even when the number of cases has been substantially reduced. Failure to implement an effective and sustainable system for HAT control and surveillance will increase the risk of a new epidemic. That would cause considerable suffering for the affected population and would be an impediment to the socioeconomic development of South Sudan. PMID:22666506

  7. A review of analytical techniques for determination of Sudan I-IV dyes in food matrixes.

    PubMed

    Rebane, Riin; Leito, Ivo; Yurchenko, Sergei; Herodes, Koit

    2010-04-23

    Sudan dyes are a family of lipophilic azo dyes, extensively used in industrial and scientific applications but banned for use as food colorants due to their carcinogenicity. Due to the continuing illicit use of Sudan dyes as food colorants their determination in different food matrices--especially in different chilli and tomato sauces and related products--has during the recent years received increasing attention all over the world. This paper critically reviews the published determination methods of Sudan I-IV dyes. LC-UV-vis and LC-MS are the dominating methods for analysis of Sudan I-IV dyes. Sudan dyes are usually found in food at mg kg(-1) levels at which it may be necessary to use a preconcentration step in order to attain the desired detection limits. Liquid-solid extraction is the dominating sample preparation procedure. In recent years it has been supplemented by ultrasonic-assisted extraction and pressurized liquid extraction. Various solid phase extraction types have been used for sample cleanup. The large majority of works use conventional C18 columns and conventional LC eluents. Traditionally the UV-vis absorbance detection has been the most frequently used. In the recent years MS detection is applied more and more often as it offers more reliable identification possibilities. PMID:20299022

  8. Extraction of Sudan dyes from environmental water by hemimicelles-based magnetic titanium dioxide nanoparticles.

    PubMed

    Li, Chenyu; Chen, Ligang; You, Xiaoxiao

    2014-11-01

    A novel method for the extraction of Sudan dyes including Sudan I, II, III, and IV from environmental water by magnetic titanium dioxide nanoparticles (Fe3O4@TiO2) coated with sodium dodecylsulfate (SDS) as adsorbent was reported. Fe3O4@TiO2 was synthesized by a simple method and was characterized by transmission electron microscopy, Fourier-transform infrared spectrometry, and vibrating sample magnetometer. The magnetic separation was quite efficient for the adsorption and desorption of Sudan dyes. The effect of the amount of SDS, extraction time, pH, desorption condition, maximal extraction volume, and humic acid on the extraction process were investigated. This method was employed to analyze three environmental water samples. The results demonstrated that our proposed method had wide linear range (25-5,000 ng L(-1)) with a good linearity (R (2) > 0.999) and low detection limits (2.9-7.3 ng L(-1)). An enrichment factor of 1,000 was achieved. In all three spiked levels (25, 250, and 2,500 ng L(-1)), the recoveries of Sudan dyes were in the range of 86.9-93.6 %. The relative standard deviations obtained were ranging from 2.5 to 9.3 %. That is to say, the new method was fast and effective for the extraction of Sudan dye from environmental water. PMID:24938811

  9. The Relationship between Leadership Style and Motivation among Faculty Members in Two Public Universities in the Republic of South Sudan

    ERIC Educational Resources Information Center

    Malok, Malok N.

    2012-01-01

    The purpose of this study was to investigate the relationship between leadership style and motivation among faculty members in two public universities in the Republic of the South Sudan. The researcher examined this issue by surveying and interviewing faculty members in two public universities in the Republic of South Sudan, a total of 67 for…

  10. 31 CFR 538.508 - Certain payments by the Government of Sudan of obligations to persons within the United States...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Sudan of obligations to persons within the United States authorized. 538.508 Section 538.508 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL... Licensing Policy § 538.508 Certain payments by the Government of Sudan of obligations to persons within...

  11. The Relationship between Leadership Style and Motivation among Faculty Members in Two Public Universities in the Republic of South Sudan

    ERIC Educational Resources Information Center

    Malok, Malok N.

    2012-01-01

    The purpose of this study was to investigate the relationship between leadership style and motivation among faculty members in two public universities in the Republic of the South Sudan. The researcher examined this issue by surveying and interviewing faculty members in two public universities in the Republic of South Sudan, a total of 67 for

  12. 76 FR 63635 - Extension of the Designation of Sudan for Temporary Protected Status and Automatic Extension of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-13

    ... extraordinary and temporary conditions within that country. See 62 FR 59737; section 244(a)(b)(1)(A), (C) of the... redesignated Sudan for TPS a total of 12 times, including this extension. See 74 FR 69355 (Dec. 31, 2009.... 69 FR 60168 (Oct. 7, 2004). The last extension of TPS for Sudan was announced on December 31,...

  13. Late Quaternary vegetation, biodiversity and fire dynamics on the southern Brazilian highland and their implication for conservation and management of modern Araucaria forest and grassland ecosystems.

    PubMed

    Behling, Hermann; Pillar, Valério DePatta

    2007-02-28

    Palaeoecological background information is needed for management and conservation of the highly diverse mosaic of Araucaria forest and Campos (grassland) in southern Brazil. Questions on the origin of Araucaria forest and grasslands; its development, dynamic and stability; its response to environmental change such as climate; and the role of human impact are essential. Further questions on its natural stage of vegetation or its alteration by pre- and post-Columbian anthropogenic activity are also important. To answer these questions, palaeoecological and palaeoenvironmental data based on pollen, charcoal and multivariate data analysis of radiocarbon dated sedimentary archives from southern Brazil are used to provide an insight into past vegetation changes, which allows us to improve our understanding of the modern vegetation and to develop conservation and management strategies for the strongly affected ecosystems in southern Brazil. PMID:17255033

  14. Electrochemical determination of Sudan I in food products using a carbon nanotube-ionic liquid composite modified electrode.

    PubMed

    Liu, Benzhi; Yin, Chuntao; Wang, Min

    2014-01-01

    A sensitive and convenient electrochemical method was developed for the determination of Sudan I using a carbon nanotube-ionic liquid composite modified electrode with the enhancement effect of cetyltrimethyl ammonium bromide (CTAB). The modified electrode exhibited an obvious electrocatalytic activity towards the oxidation of Sudan I, and the oxidation peak current significantly increased in the presence of CTAB. The experimental parameters, such as solution pH, concentration of CTAB and accumulation time, were optimised for Sudan I determination. The oxidation peak current showed a linear relationship with the concentration of Sudan I in the range of 3.0 × 10(-8) to 3.1 × 10(-6) mol l(-1), with a detection limit of 8.0 × 10(-9) mol l(-1). The proposed method was successfully applied for the determination of Sudan I in food products of ketchup and chilli sauce. PMID:25254422

  15. Women's experiences in the armed conflict situation in Sudan.

    PubMed

    1999-01-01

    The negative impact of war is apparent at various levels of the Sudanese society. Economic, social, and political instability is occurring on a large scale and the most vulnerable groups are women and children. This report aimed to document women's human rights violations in the ongoing armed conflict situation in Sudan, with the emphasis on rape; investigate the forms of violence against women in a situation of armed conflict; present testimonies of women survivors; and use the document for advocacy. A total of 20 testimonies were obtained, which clearly indicated that rape is a systematic practice in areas of conflict regardless of whether the Sudanese People's Liberation Army, the Khartoum government, or bandit groups that take advantage of the chaos, have attacked civilians. In view of this, regional agencies should show more seriousness in finding solutions for the war, and perpetrators of rape should be brought to justice so as to change the perception of rape as an unfortunate but inevitable side effect of war. PMID:12179109

  16. Addressing malaria vector control challenges in South Sudan: proposed recommendations.

    PubMed

    Chanda, Emmanuel; Doggale, Constantino; Pasquale, Harriet; Azairwe, Robert; Baba, Samson; Mnzava, Abraham

    2013-01-01

    Upon the signing of the Comprehensive Peace Agreement in 2005, the Republic of South Sudan (RSS) has faced a lot of challenges, such as a lack of infrastructure, human resources and an enormous burden of vector borne diseases including malaria. While a national malaria strategic plan 2006-2011 was developed, the vector control component has remained relatively weak. The strategy endorses the distribution of long-lasting insecticidal nets (LLINs) as the frontline intervention with other interventions recommended only when technical and institutional capacity is available. In 2006, a draft integrated vector management (IVM) strategic plan 2007-2012 was developed but never implemented, resulting in minimal coordination, implementation and coverage of malaria vector control tools including their inherent impact. To address this challenge, the vector control team of the National Malaria Control Programme (NMCP) is being strengthened. With the objective of building national capacity and technical collaboration for effective implementation of the IVM strategy, a national malaria vector control conference was held from 15-17th October 2012 in Juba. A range of NMCP partners, state ministries, acadaemia, private sector, national and international non-governmental organizations, including regional and global policymakers attended the meeting. The conference represented a major milestone and made recommendations revolving around the five key elements of the IVM approach. The meeting endorsed that vector control efforts in RSS be augmented with other interventions within the confines of the IVM strategy as a national approach, with strong adherence to its key elements. PMID:23394124

  17. Respiratory symptoms and occupational bronchitis in chromite ore miners, Sudan.

    PubMed

    Ballal, S G

    1986-10-01

    Prevalence of respiratory symptoms and chronic bronchitis was determined in a group of 122 subjects (77 exposed miners, 18 partially exposed, 27 controls) working at chromite ore mines in Sudan. The mean ages (+/- s.d.) of the three groups were 36.4 (+/- 7.8), 35.2 (+/- 6.8) and 34.6 (+/- 7.5) years respectively. Methods included a respiratory symptoms questionnaire based on the British Medical Research Council (MRC 1976) questionnaire on respiratory symptoms, determination of FEV1, FVC and FEV1/FVC%. The majority (66%) of the exposed subjects were non-smokers (NS) and 20 (77%) of the 'ever-smokers' (current and ex-smokers) were smokers of less than 15 cigarettes day-1. Respiratory symptoms (cough, phlegm, dyspnoea) were more frequent among the miners and so was chronic bronchitis. The prevalence of the latter was 26% among the miners compared to 11% and 7% among the partially exposed and the controls respectively. These differences could not be accounted for by cigarette smoking. Sixty-five per cent of the miners diagnosed as having asthma, chronic bronchitis or both were non-smokers. Although the values for the FEV1/FVC% remained normal or near the lower limits of the normal range, the mean value was significantly lower among the miners. It was concluded that the mine dust was the prime cause of the respiratory symptoms and chronic bronchitis among the miners. PMID:3795322

  18. Epidemiology of Substance Use among University Students in Sudan.

    PubMed

    Osman, Tarig; Victor, Cathrine; Abdulmoneim, Alaa; Mohammed, Hala; Abdalla, Fatima; Ahmed, Asma; Ali, Eiman; Mohammed, Wael

    2016-01-01

    Background. Youth populations are vulnerable to substance use particularly in developing countries where circumstances may be favorable for it. There is no published data on substance use among the youth in Sudan other than on tobacco use. Objectives. The aim of this study was to investigate the prevalence, circumstances, and factors associated with substance use. Methods. An institution-based survey was conducted on a sample of 500 students. Data was collected using a questionnaire designed by the WHO for student drug surveys and analyzed using IBM SPSS version 20. Results. The overall prevalence of substance use is 31%. The current prevalence of tobacco, cannabis, alcohol, amphetamines, tranquilizers, inhalants, opiates, cocaine, and heroin use was 13.7%, 4.9%, 2.7%, 2.4%, 3.2%, 1%, 1.2%, 0.7%, and 0.5%, respectively. Curiosity (33.1%) was the main reason for initiation of substance use. The main adverse effects reported were health problems (19.7%) and theft (19.7%). Peers (40.9%) were the prime source of substance use. On multivariate analysis, male sex was the principle predictor for substance use (AOR: 5.55; 95% CI: 3.38, 9.17). Conclusion. Strategies to control substance use should encompass the role of the university and parents in observing and providing education to improve awareness of substances and their consequences. PMID:27006856

  19. Ethical, legal and social aspects of the approach in Sudan.

    PubMed

    El Sayed, Badria B; Malcolm, Colin A; Babiker, Ahmed; Malik, Elfatih M; El Tayeb, Mohammed A H; Saeed, Nageeb S; Nugud, Abdel Hameed D; Knols, Bart G J

    2009-01-01

    The global malaria situation, especially in Africa, and the problems frequently encountered in chemical control of vectors such as insecticide resistance, emphasize the urgency of research, development and implementation of new vector control technologies that are applicable at regional and local levels. The successful application of the sterile insect technique (SIT) for the control of the New World screwworm Cochliomyia hominivorax and several species of fruit flies has given impetus to the use of this method for suppression or elimination of malaria vectors in some areas of Africa including Northern State of Sudan. The research and development phase of the Northern State feasibility study has been started. Sudanese stakeholders are working side-by-side with the International Atomic Energy Agency in the activities of this important phase. Several ethical, legal and social issues associated with this approach arose during this phase of the project. They need to be seriously considered and handled with care. In this paper, these issues are described, and the current and proposed activities to overcome potential hurdles to ensure success of the project are listed. PMID:19917073

  20. Modelling of sedimentation processes inside Roseires Reservoir (Sudan)

    NASA Astrophysics Data System (ADS)

    Omer, A. Y. A.; Ali, Y. S. A.; Roelvink, J. A.; Dastgheib, A.; Paron, P.; Crosato, A.

    2015-04-01

    Roseires Reservoir, located on the Blue Nile River in Sudan, is the first trap to the sediments coming from the vast upper river catchment in Ethiopia, which suffers from high erosion and desertification problems. The reservoir has already lost more than one-third of its storage capacity due to sedimentation in the last four decades. Appropriate management of the eroded soils in the upper basin could mitigate this problem. In order to do that, the areas providing the highest sediment volumes to the river have to be identified, since they should have priority with respect to the application of erosion control practices. This requires studying the sedimentation record inside Roseires Reservoir in order to assess when and how much sediment is deposited and to identify its source. This paper deals with the identification of deposition time and soil stratification inside the reservoir, based on historical bathymetric data, numerical modelling and newly acquired soil data. The remoteness of the study area and the extreme climate result in coring campaigns being expensive and difficult. Therefore, these activities need to be optimised and coring locations selected beforehand. This was done by combining bathymetric data and the results of a depth-averaged morphodynamic model recording the vertical stratification in sediment deposits. The model allowed for recognising the areas that are potentially subject to neither net erosion nor bar migration during the lifespan of the reservoir. Verification of these results was carried out by analysing sediment stratification from the data collected during the subsequent field campaign.

  1. Evapotranspiration computed by Darcy's Law: Sudan case study

    NASA Astrophysics Data System (ADS)

    Abdalla, O. A. E.

    2005-08-01

    The present study applies Darcy's Law to compute evapotranspiration in the arid to semi-arid central Sudan. The average decline in groundwater level (s) along a distance (L) of the aquifer's cross section was calculated. Such decline is a function of discharge Q at any point across the unit width of the aquifer and effective porosity. Groundwater in the study area generally flows from NW to the SE along basin axial trough and is characterized by variable hydraulic gradient. As the aquifer discharge is directly proportional to the gradient, different values of groundwater level decline were calculated along the flow direction. The hydrogeological map constructed during this study indicates that the system is hydrologicaly closed and groundwater doesn't discharge in the neighboring White Nile River. Geological, hydrological and climatological settings of the discharge area demonstrate that evapotranspiration is the main mechanism of groundwater discharge and reveals that the area is suited for the application of Darcy's Law to compute evapotranspiration. Evapotranspiration was estimated from Darcy's law to be 1.2 mm/a and is sufficient to balance the present system. Greater similarity in geology, hydrology, climate and vegetation encourages the application of Darcy's Law in the Sahara and sub-Sahara to compute for evapotranspiration. Such cost effective method can be applied in arid to semi-arid areas if conditions are favorable.

  2. Epidemiology of Substance Use among University Students in Sudan

    PubMed Central

    Osman, Tarig; Victor, Cathrine; Abdulmoneim, Alaa; Mohammed, Hala; Abdalla, Fatima; Ahmed, Asma; Ali, Eiman; Mohammed, Wael

    2016-01-01

    Background. Youth populations are vulnerable to substance use particularly in developing countries where circumstances may be favorable for it. There is no published data on substance use among the youth in Sudan other than on tobacco use. Objectives. The aim of this study was to investigate the prevalence, circumstances, and factors associated with substance use. Methods. An institution-based survey was conducted on a sample of 500 students. Data was collected using a questionnaire designed by the WHO for student drug surveys and analyzed using IBM SPSS version 20. Results. The overall prevalence of substance use is 31%. The current prevalence of tobacco, cannabis, alcohol, amphetamines, tranquilizers, inhalants, opiates, cocaine, and heroin use was 13.7%, 4.9%, 2.7%, 2.4%, 3.2%, 1%, 1.2%, 0.7%, and 0.5%, respectively. Curiosity (33.1%) was the main reason for initiation of substance use. The main adverse effects reported were health problems (19.7%) and theft (19.7%). Peers (40.9%) were the prime source of substance use. On multivariate analysis, male sex was the principle predictor for substance use (AOR: 5.55; 95% CI: 3.38, 9.17). Conclusion. Strategies to control substance use should encompass the role of the university and parents in observing and providing education to improve awareness of substances and their consequences. PMID:27006856

  3. Correlation of measles and dengue infection in Kassala, Eastern Sudan.

    PubMed

    Abdalla, Tajeldin M; Karsany, Mubarak S; Ali, AbdelAziem A

    2015-01-01

    Using the clinical case definition adopted by the World Health Organization, a total of 275 suspected cases of measles were enrolled in this study during January-March 2012 in Kassala Teaching Hospital, Eastern Sudan. Various clinical manifestations (fever, headache, cough, coryza, conjunctivitis, skin rash, vomiting, diarrhoea, convulsion, and hemorrhagic manifestations) were reported among these patients. Blood was withdrawn from the first 64 (23.3%) patients. Two samples were hemolyzed and only 60 samples (21.8%) were investigated for measles and dengue IgM antibodies. Antibodies for measles, dengue, and co-infection were detected in the plasma of 12 (20%), seven (11.7%), and 10 (16.7%) samples, respectively. Although there was no significant difference in age, residence, occupation, and vaccination status among the different groups, a high proportion of male patients (P = 0.011), severe cases (P = 0.004), and death ((P = 0.001) were reported among co-infected cases. PMID:24980486

  4. Cystic echinococcosis in Mundari tribe-members of South Sudan

    PubMed Central

    Stewart, Barclay T; Jacob, Joseph; Finn, Timothy; Lado, Mounir; Napoleon, Robert; Brooker, Simon; Sidhu, Paul S; Kolaczinski, Jan

    2013-01-01

    Many neglected tropical diseases, including the zoonotic disease cystic echinococcosis (hydatidosis), are endemic to East Africa. However, their geographical distribution is heterogenous and incompletely characterized. The aim of this study was to determine if Mundari pastoralists harbor endemic human hydatidosis. The survey was conducted in cattle camps randomly selected from accessible sites provided by officials in Terekeka, South Sudan. Following informed consent, a questionnaire collected demographic data and hydatid exposure risk. A systematic sonographic abdominal exam was performed using General Electrics LOGIQ Book XP with a 3C-RS 25 MHz curvilinear transducer. Six hundred and ten individuals were screened from 13 camps. Four infections were identified, all in women. The prevalence of abdominal hydatid disease in the Mundari tribe-members in cattle camps was 0.7% and all individuals reporting at least one high-risk exposure to hydatid disease. Cystic echinococcosis is endemic among Mundari pastoralists; however, it would appear to be less endemic than in neighboring tribes. PMID:24139620

  5. Agricultural pesticide exposure and perinatal mortality in central Sudan.

    PubMed Central

    Taha, T. E.; Gray, R. H.

    1993-01-01

    Hospital- and community-based studies were conducted in central Sudan to investigate the association between pesticide exposure and perinatal mortality. The cases were 197 stillbirths in the hospital and 36 perinatal deaths in the community; the controls were 812 liveborn, normal-birth-weight infants in the hospital, and 1505 liveborn infants who survived for the first 7 days after birth in the community. The odds ratio (OR) of perinatal death associated with pesticide exposure was estimated using multiple logistic regression. There was a consistent and significant association between pesticide exposure and perinatal mortality in the hospital (adjusted OR = 1.9; 95% confidence interval (CI): 1.3-2.8) and the community populations (adjusted OR = 2.7; 95% CI: 1.1-6.4). The OR was significantly higher among women engaged in farming (3.6; 95% CI: 1.6-8.0), but not among women in nonfarming occupations (1.6; 95% CI: 0.8-3.3). The estimated attributable risks of perinatal death owing to pesticide exposure were 22.6% for hospital stillbirths and 15.7% for community perinatal deaths; but among women engaged in farming in the hospital population the attributable risks were substantially higher (34.5%). PMID:8324850

  6. On the azo/hydrazo equilibrium in Sudan I azo dye derivatives.

    PubMed

    Ferreira, Gilson R; Garcia, Humberto Costa; Couri, Mara Rubia C; Dos Santos, Hélio F; de Oliveira, Luiz Fernando C

    2013-01-24

    In this study, Raman, infrared, UV/vis, NMR, and single crystal X-ray diffraction spectroscopies are used to elucidate the tautomeric equilibrium of azo dyes derived from 1-phenyl-azo-2-naphthol (Sudan I). A new crystallographic structure is described for Sudan I, revealing the presence of intramolecular hydrogen bonds and supramolecular interactions, such as the unconventional C-H···O hydrogen bond type, π-stacking, and charge-dipole interactions. All of these weak intermolecular interactions play a role in the stability of the crystalline structure. Theoretical calculations are also reported for geometries, energy, and spectroscopic properties. The predicted spectra are in accordance with the experiments carried out in the solid state and in solution of dichloromethane, carbon tetrachloride, and chloroform, suggesting the hydrazo form as the preferable tautomer in gas and condensate phases for Sudan I and its derivatives. PMID:23289665

  7. Cenozoic tectonic and climatic events in southern Iberian Peninsula: Implications for the evolutionary history of freshwater fish of the genus Squalius (Actinopterygii, Cyprinidae).

    PubMed

    Perea, Silvia; Cobo-Simon, Marta; Doadrio, Ignacio

    2016-04-01

    Southern Iberian freshwater ecosystems located at the border between the European and African plates represent a tectonically complex region spanning several geological ages, from the uplifting of the Betic Mountains in the Serravalian-Tortonian periods to the present. This area has also been subjected to the influence of changing climate conditions since the Middle-Upper Pliocene when seasonal weather patterns were established. Consequently, the ichthyofauna of southern Iberia is an interesting model system for analyzing the influence of Cenozoic tectonic and climatic events on its evolutionary history. The cyprinids Squalius malacitanus and Squalius pyrenaicus are allopatrically distributed in southern Iberia and their evolutionary history may have been defined by Cenozoic tectonic and climatic events. We analyzed MT-CYB (510 specimens) and RAG1 (140 specimens) genes of both species to reconstruct phylogenetic relationships and to estimate divergence times and ancestral distribution ranges of the species and their populations. We also assessed their levels of genetic structure and diversity as well as the amount of gene flow between populations. To investigate recent paleogeographical and climatic factors in southern Iberia, we modeled changes-through-time in sea level from the LGM to the present. Phylogenetic, geographic and population structure analyses revealed two well-supported species (S. malacitanus and S. pyrenaicus) in southern Iberia and two subclades (Atlantic and Mediterranean) within S. malacitanus. The origin of S. malacitanus and the separation of its Atlantic and Mediterranean populations occurred during the Serravalian-Tortonian and Miocene-Pliocene periods, respectively. These divergence events occurred in the Middle Pliocene and Pleistocene in S. pyrenaicus. In both species, Atlantic basins possessed populations with higher genetic diversity than Mediterranean, which may be explained by the Janda Lagoon. The isolation of S. malacitanus was earlier and related to the rising of the Betic Mountains. Divergence of its Atlantic and Mediterranean populations was associated with the creation of the freshwater systems of southern Iberia close to the Gibraltar Strait. The presence of S. pyrenaicus in southern Iberia may be the result of recent colonization associated with river capture, as demonstrated our biogeographic reconstruction. PMID:26785110

  8. Right-lateral displacements and the Holocene slip rate associated with prehistoric earthquakes along the southern Panamint Valley fault zone: Implications for southern Basin and Range tectonics and coastal California deformation

    SciTech Connect

    Peizhen Zhang; Ellis, M.; Slemmons, D.B.; Fengying Mao )

    1990-04-10

    The N 20{degree}W-trending Panamint Valley fault zone is linked to the N 60{degree}W-trending Hunter Mountain strike-slip fault and the Saline Valley fault system, which represents on of the three major fault systems accommodating active crustal extension in the southern Great Basin. The displacement associated with the most recent event, determined through six detailed topographic maps of offset features, is 3.2 {plus minus} 0.5 m, and a number of larger offsets, in range of 6-7 m and 12 m, are also observed. If the larger displacements represent, respectively, two and three events, each of {approximately} 3 m, then the fault zone appears to be associated with a characteristic earthquake, which the authors estimate from the length of the rupture zone and the displacement to be between (Ms) 6.5 and 7.2. The Holocene slip rate is 2.36 {plus minus} 0.79 mm/yr, is determined from the displacement of two alluvial features whose maximum age is estimated from pluvial shorelines. Assuming a characterisitc earthquake model, the recurrence interval is between 860 and 2,360 years. The total slip vector of the southern Panamint Valley fault system is oriented toward {approximately} N 35{degree}W, making this a predominately strike-slip fault. In conjunction with the N 60{degree}W orientation of the Hunter mountain strike-slip fault, the authors suggest that the displacement vector for the southern Great Basin is toward the NW, consistent with results from VLBI data, rather than WNW as determined by combining VLBI and geological data. This is turn suggests that the coastal California deformation component involves, respectively, less shortening and more strike-slip displacement perpendicular and parallel to the San Andreas fault than is currently proposed.

  9. Towards global Guinea worm eradication in 2015: the experience of South Sudan.

    PubMed

    Awofeso, Niyi

    2013-08-01

    For centuries, the Guinea worm parasite (Dracunculus medinensis) has caused disabling misery, infecting people who drink stagnant water contaminated with the worm's larvae. In 2012, there were 542 cases of Guinea worm reported globally, of which 521 (96.1%) were reported in South Sudan. Protracted civil wars, an inadequate workforce, neglect of potable water provision programs, suboptimal Guinea worm surveillance and case containment, and fragmented health systems account for many of the structural and operational factors encumbering South Sudan's Guinea worm eradication efforts. This article reviews the impacts of six established Guinea worm control strategies in South Sudan: (1) surveillance to determine actual caseload distribution and trends in response to control measures; (2) educating community members from whom worms are emerging to avoid immersing affected parts in sources of drinking water; (3) filtering potentially contaminated drinking water using cloth filters or filtered drinking straws; (4) treating potentially contaminated surface water with the copepod larvicide temephos (Abate); (5) providing safe drinking water from boreholes or hand-dug wells; and (6) containment of transmission through voluntary isolation of each patient to prevent contamination of drinking water sources, provision of first aid, and manual extraction of the worm. Surveillance, community education, potable water provision, and case containment remain weak facets of the program. Abate pesticide is not a viable option for Guinea worm control in South Sudan. In light of current case detection and containment trends, as well as capacity building efforts for Guinea worm eradication, South Sudan is more likely to eradicate Guinea worm by 2020, rather than by 2015. The author highlights areas in which substantial improvements are required in South Sudan's Guinea worm eradication program, and suggests improvement strategies. PMID:23623648

  10. Characterization of epidemic and nonepidemic Neisseria meningitidis serogroup A strains from Sudan and Sweden.

    PubMed Central

    Salih, M A; Danielsson, D; Bäckman, A; Caugant, D A; Achtman, M; Olcén, P

    1990-01-01

    A random selection of 25 strains isolated during an epidemic caused by serogroup A Neisseria meningitidis in Sudan (1988), 3 preepidemic meningococcal strains (1985), and 26 serogroup A strains isolated from sporadic cases of meningitis in Sweden (1973 to 1987) were assessed for multilocus enzyme genotypes (ETs), DNA restriction enzyme patterns, outer membrane proteins, lipopolysaccharides, pilus formation, and antibiograms. All of the 25 Sudanese epidemic isolates and 22 of the Swedish strains were of the same or closely related ETs (ETs 3, 4, and 5), corresponding to clone III-1, which has been responsible for two pandemic waves in the last three decades. The earlier pandemic involved Scandinavia, and the last one caused an outbreak during the pilgrimage to Mecca, Saudi Arabia (August 1987), spreading to Sudan, Chad, and Ethiopia. The three Sudanese preepidemic isolates (1985) were clone IV-1 (sulfonamide susceptible), which has been resident in the African meningitis belt for the last 25 years. The uniformity of clone III-1 strains (all sulfonamide resistant) from Sudan and Sweden was confirmed by DNA restriction enzyme patterns. ETs 3, 4, and 5 from Sudan and Sweden had 86 to 100% similarity to a Swedish clone III-1 reference strain, whereas ETs 1, 2, 6, and 7 showed 50 to 80% similarity. Class 1 protein for clone III-1 showed serosubtype antigens P1.9 and P1.x, whereas ET6 strains (clone IV-1) had serosubtype P1.7. Lipopolysaccharides were variable in the Sudanese and Swedish strains. Pili were expressed in all clone III-1 isolates from Sudan and Sweden but in none of the clone IV-1 isolates (Sudan, 1985). Images PMID:1975593

  11. Seasonal variation of carbon fluxes in a sparse savanna in semi arid Sudan

    PubMed Central

    Ardö, Jonas; Mölder, Meelis; El-Tahir, Bashir Awad; Elkhidir, Hatim Abdalla Mohammed

    2008-01-01

    Background Large spatial, seasonal and annual variability of major drivers of the carbon cycle (precipitation, temperature, fire regime and nutrient availability) are common in the Sahel region. This causes large variability in net ecosystem exchange and in vegetation productivity, the subsistence basis for a major part of the rural population in Sahel. This study compares the 2005 dry and wet season fluxes of CO2 for a grass land/sparse savanna site in semi arid Sudan and relates these fluxes to water availability and incoming photosynthetic photon flux density (PPFD). Data from this site could complement the current sparse observation network in Africa, a continent where climatic change could significantly impact the future and which constitute a weak link in our understanding of the global carbon cycle. Results The dry season (represented by Julian day 35–46, February 2005) was characterized by low soil moisture availability, low evapotranspiration and a high vapor pressure deficit. The mean daily NEE (net ecosystem exchange, Eq. 1) was -14.7 mmol d-1 for the 12 day period (negative numbers denote sinks, i.e. flux from the atmosphere to the biosphere). The water use efficiency (WUE) was 1.6 mmol CO2 mol H2O-1 and the light use efficiency (LUE) was 0.95 mmol CO2 mol PPFD-1. Photosynthesis is a weak, but linear function of PPFD. The wet season (represented by Julian day 266–273, September 2005) was, compared to the dry season, characterized by slightly higher soil moisture availability, higher evapotranspiration and a slightly lower vapor pressure deficit. The mean daily NEE was -152 mmol d-1 for the 8 day period. The WUE was lower, 0.97 mmol CO2 mol H2O-1 and the LUE was higher, 7.2 μmol CO2 mmol PPFD-1 during the wet season compared to the dry season. During the wet season photosynthesis increases with PPFD to about 1600 μmol m-2s-1 and then levels off. Conclusion Based on data collected during two short periods, the studied ecosystem was a sink of carbon both during the dry and wet season 2005. The small sink during the dry season is surprising and similar dry season sinks have not to our knowledge been reported from other similar savanna ecosystems and could have potential management implications for agroforestry. A strong response of NEE versus small changes in plant available soil water content was found. Collection and analysis of flux data for several consecutive years including variations in precipitation, available soil moisture and labile soil carbon are needed for understanding the year to year variation of the carbon budget of this grass land/sparse savanna site in semi arid Sudan. PMID:19046418

  12. Genetic diversity and population structure of Plasmodium vivax isolates from Sudan, Madagascar, French Guiana and Armenia.

    PubMed

    Menegon, Michela; Durand, Patrick; Menard, Didier; Legrand, Eric; Picot, Stéphane; Nour, Bakri; Davidyants, Vladimir; Santi, Flavia; Severini, Carlo

    2014-10-01

    Polymorphic genetic markers and especially microsatellite analysis can be used to investigate multiple aspects of the biology of Plasmodium species. In the current study, we characterized 7 polymorphic microsatellites in a total of 281 Plasmodium vivax isolates to determine the genetic diversity and population structure of P. vivax populations from Sudan, Madagascar, French Guiana, and Armenia. All four parasite populations were highly polymorphic with 3-32 alleles per locus. Mean genetic diversity values was 0.83, 0.79, 0.78 and 0.67 for Madagascar, French Guiana, Sudan, and Armenia, respectively. Significant genetic differentiation between all four populations was observed. PMID:25102032

  13. Southern Africa

    Atmospheric Science Data Center

    2013-04-16

    article title: Southern Africa View larger JPEG image ... visibility of smoke plumes and haze. The southern tip of South Africa is at the bottom of the image, and Zambia is at the top. ... MISR Team. Aug 25, 2000 -South Africa to Zambia including the Okavango Delta. project: ...

  14. A comparison of the physics of the northern and southern shelves of the eastern Bering Sea and some implications for the ecosystem

    NASA Astrophysics Data System (ADS)

    Stabeno, Phyllis J.; Farley, Edward V., Jr.; Kachel, Nancy B.; Moore, Sue; Mordy, Calvin W.; Napp, Jeffrey M.; Overland, James E.; Pinchuk, Alexei I.; Sigler, Michael F.

    2012-06-01

    Sufficient oceanographic measurements have been made in recent years to describe the latitudinal variation in the physics of the eastern Bering Sea shelf and the potential impact of climate change on the species assemblages in the two ecosystems (north and south). Many of the predicted ecosystem changes will result from alterations in the timing and extent of sea ice. It is predicted that the sea ice in the northern Bering Sea will be less common in May, but will continue to be extensive through April. In contrast, the southern shelf will have, on average, much less sea ice than currently observed, but with large interannual and multiyear variability until at least 2050. Thus, even under current climate warming scenarios, bottom temperatures on the northern shelf will remain cold. Based on biophysical measurements, the southern and northern ecosystems were divided by a North-South Transition at ˜60°N. The northern middle shelf was characterized by a freshwater lens at the surface, cold bottom temperatures, and a thicker pycnocline than found on the southern shelf. Subsurface phytoplankton blooms were common. In contrast, the southern shelf stratification was largely determined by temperature alone; the pycnocline was thin (often<3 m) and subsurface blooms were uncommon. Biological responses to climate warming could include greater north-south differences in zooplankton community structure, the transport of large Outer Shelf Domain crustacean zooplankton to the middle shelf, and the disappearance of two principal prey taxa (Calanus spp. and Thysanoessa spp.) of planktivorous fish, seabirds and whales. The response of commercially and ecologically important fish species is predicted to vary. Some species of fish (e.g., juvenile sockeye salmon, Oncorhynchus nerka) may expand their summer range into the northern Bering Sea; some (e.g., pink salmon, O. gorbuscha) may increase in abundance while still other species (e.g., walleye pollock and arrowtooth flounder; Theragra chalcogramma and Atheresthes stomias, respectively) are unlikely to become common in the north. The projected warming of the southern shelf will limit the distribution of arctic species (e.g., snow crab, Chionoecetes opilio) to the northern shelf and will likely permit expansion of subarctic species into the southern Bering Sea. The distribution and abundance of baleen whales will respond to shifts in prey availability; for instance, if prey are advected northward from the southeastern Bering Sea, an extension of range and an increase in seasonally migratory baleen whale numbers is anticipated. Thus, alteration of this ecosystem in response to climate change is expected to result in something other than a simple northward shift in the distribution of all species.

  15. Using apatite (U-Th)/He thermochronometry to resolve regional unroofing patterns across the interior of the southern African Plateau and implications for mantle dynamics

    NASA Astrophysics Data System (ADS)

    Stanley, J. R.; Flowers, R. M.

    2011-12-01

    The southern African Plateau is a long wavelength physiographic feature characterized by elevated Archean and Proterozoic cratonic lithosphere surrounded by a horseshoe shaped "Great Escarpment" which drops to the coastal plane. The average elevation of the plateau interior is ~1 km, ~0.5 km higher than average cratons. Unlike other major continental plateaus, southern Africa is surrounded by divergent margins which formed during the Jurassic breakup of Gondwana. The mechanisms for plateau uplift are intensely debated and include mantle drivers such as shallow convection or dynamic topography related to the southern African superplume. Constraining the timing and patterns of uplift can help to differentiate these competing explanations for the high topography. Thermochronological studies can yield critical information regarding unroofing histories to help decipher the timing and causes of plateau elevation gain. Previous studies using apatite fission-track (AFT) thermochronology mostly focused on transects across southern portions of the Great Escarpment. However, despite its importance for resolving large-scale unroofing patterns, there is limited thermochronological information from the plateau interior. This is in part because the temperature sensitivity of the AFT system may be somewhat higher than that required to tightly resolve the lower magnitudes of unroofing in the plateau interior relative to the coastal plain. The (U-Th)/He system in apatite (AHe) is particularly well-suited to this problem because its sensitivity to temperatures as low as ~30°C allows unroofing events in the upper 1-2 km of crust to be detected. Here we present the first AHe dataset from a broad swath across the interior of the plateau from northern South Africa and Botswana. New AHe data for eight Proterozoic diabase samples yield Cretaceous dates that display an interesting bimodal distribution of data. These results suggest at least 1.5 km of unroofing across this portion of the plateau interior since Cretaceous time. The only published AHe data for southern Africa (Flowers and Schoene 2009) comes from across the Great Escarpment in the Barberton region of South Africa and Swaziland. Those results are also Cretaceous with dates clustering ~100 Ma. Our new data, when combined with the previously published results, complete a large scale, ~900 km long, transect of AHe data from the coastal plain across the Great Escarpment well into the interior of the plateau. This full dataset suggests an intriguing spatial variability in dates, and shows the promise of using AHe data to decipher unroofing patterns across the continent to help better understand the mantle processes responsible for the rise of the southern African Plateau.

  16. The curious case of the date of introduction of leaded fuel to Australia: Implications for the history of Southern Hemisphere atmospheric lead pollution

    NASA Astrophysics Data System (ADS)

    Cook, D. E.; Gale, S. J.

    By comparison with the Northern Hemisphere, the history of atmospheric lead pollution in the Southern Hemisphere is still poorly understood. Until recently, the main source of atmospheric lead fallout in the Southern Hemisphere was tetraethyl lead from motor fuel and for most of the 20th century the most important single source of this pollutant was Australia. Yet there is little agreement over when leaded fuel made its first appearance in Australia. Reported dates range from the early 1920s to the late 1940s. A study of oil company advertisements and reports in motoring and oil company journals shows that leaded petrol first became available in Australia in August 1932. This date is important both for the reconstruction of lead pollution histories and in the use of lead stratigraphies to determine chronology.

  17. Detrital Geochemical Fingerprints of Rivers Along Southern Tibet and Nepal: Implications for Erosion of the Indus-Yarlung Suture Zone and the Himalayas

    NASA Astrophysics Data System (ADS)

    Hassim, M. F. B.; Carrapa, B.; DeCelles, P. G.; Kapp, P. A.; Gehrels, G. E.

    2014-12-01

    Our detrital geochemical study of modern sand collected from tributaries of the Yarlung River in southern Tibet and the Kali Gandaki River and its tributaries in Nepal shed light on the ages and exhumation histories of source rocks within the Indus-Yarlung Suture (IYS) zone and the Himalayas. Seven sand samples from rivers along the suture zone in southern Tibet between Xigatze to the east and Mt. Kailas to the west were collected for detrital zircon U-Pb geochronologic and Apatite Fission Track (AFT) thermochronologic analyses. Zircon U-Pb ages for all rivers range between 15 and 3568 Ma. Rivers draining the northern side of the suture zone mainly yield ages between 40 and 60 Ma, similar to the age of the Gangdese magmatic arc. Samples from rivers draining the southern side of the suture zone record a Tethyan Himalayan signal characterized by age clusters at 500 Ma and 1050 Ma. Our results indicate that the ages and proportion of U-Pb zircons ages of downstream samples from tributaries of the Yarlung River directly reflect source area ages and relative area of source rock exposure in the catchment basin. Significant age components at 37 - 40 Ma, 47 - 50 Ma, 55 - 58 Ma and 94 - 97 Ma reflect episodicity in Gangdese arc magmatism. Our AFT ages show two main signals at 23-18 Ma and 12 Ma, which are in agreement with accelerated exhumation of the Gangdese batholith during these time intervals. The 23 - 18 Ma signal partly overlaps with deposition of the Kailas Formation along the suture zone and may be related to exhumation due to upper plate extension in southern Tibet in response to Indian slab rollback and/or break-off events. Detrital thermochronology of four sand samples from the Kali Gandaki River and some of its tributaries in Nepal is underway and will provide constraints on the timing of erosion of the central Nepal Himalaya.

  18. Ebola haemorrhagic fever in Sudan, 1976. Report of a WHO/International Study Team.

    PubMed

    1978-01-01

    A large outbreak of haemorrhagic fever (subsequently named Ebola haemorrhagic fever) occurred in southern Sudan between June and November 1976. There was a total of 284 cases; 67 in the source town of Nzara, 213 in Maridi, 3 in Tembura, and 1 in Juba. The outbreak in Nzara appears to have originated in the workers of a cotton factory. The disease in Maridi was amplified by transmission in a large, active hospital. Transmission of the disease required close contact with an acute case and was usually associated with the act of nursing a patient. The incubation period was between 7 and 14 days. Although the link was not well established, it appears that Nzara could have been the source of infection for a similar outbreak in the Bumba Zone of Zaire.In this outbreak Ebola haemorrhagic fever was a unique clinical disease with a high mortality rate (53% overall) and a prolonged recovery period in those who survived. Beginning with an influenza-like syndrome, including fever, headache, and joint and muscle pains, the disease soon caused diarrhoea (81%), vomiting (59%), chest pain (83%), pain and dryness of the throat (63%), and rash (52%). Haemorrhagic manifestations were common (71%), being present in half of the recovered cases and in almost all the fatal cases.Two post mortems were carried out on patients in November 1976. The histopathological findings resembled those of an acute viral infection and although the features were characteristic they were not exclusively diagnostic. They closely resembled the features described in Marburg virus infection, with focal eosinophilic necrosis in the liver and destruction of lymphocytes and their replacement by plasma cells. One case had evidence of renal tubular necrosis.Two strains of Ebola virus were isolated from acute phase sera collected from acutely ill patients in Maridi hospital during the investigation in November 1976. Antibodies to Ebola virus were detected by immunofluorescence in 42 of 48 patients in Maridi who had been diagnosed clinically, but in only 6 of 31 patients in Nzara. The possibility of the indirect immunofluorescent test not being sufficiently sensitive is discussed.Of Maridi case contacts, in hospital and in the local community, 19% had antibodies. Very few of them gave any history of illness, indicating that Ebola virus can cause mild or even subclinical infections. Of the cloth room workers in the Nzara cotton factory, 37% appeared to have been infected, suggesting that the factory may have been the prime source of infection. PMID:307455

  19. Petrology of Nile River sands (Ethiopia and Sudan): Sediment budgets and erosion patterns

    NASA Astrophysics Data System (ADS)

    Garzanti, Eduardo; Andò, Sergio; Vezzoli, Giovanni; Ali Abdel Megid, Ada; El Kammar, Ahmed

    2006-12-01

    Detrital modes of modern Nile sands, together with estimates of sediment volumes trapped in Sudanese reservoirs, allow us to calculate sediment loads of major tributaries (Blue Nile, White Nile, Atbara) and erosion rates in the Nile catchment. A tridimensional array of high-resolution bulk-petrography and heavy-mineral data was obtained on both levee (suspended load) and bar (bedload) deposits, analysed separately for each grain-size subclass at 0.5 Φ intervals. From available information on sediments stored in the Roseires, Khashm el Girba and Lake Nasser reservoirs between 1964 and 1990, the total Nile load is reassessed at 230 ± 20 10 6 t/a, an estimate two to four times higher than figures reported so far, on which previous estimates of sediment yields and erosion rates were based. Of such huge amount of detritus, 82 ± 10 10 6 t/a are contributed by River Atbara, which carries more volcanic rock fragments, brown augite and olivine from basaltic rocks, and 140 ± 20 10 6 t/a by the Blue Nile, which carries more K-feldspar and hornblende from amphibolite-facies basement rocks. The additional ≤ 10 7 t/a of almost purely quartzose sediments supplied by the rest of the Nile catchment, corresponding to insignificant average yields and erosion rates, represent the stable residue which survived extreme subequatorial weathering in southern Sudan swamps (White Nile, Bahr ez Zeraf, and Sobat sands) or fluvial and eolian recycling of ancient quartzarenites in hyperarid climates (Nubian sands). Sediment production is thus markedly focused on Ethiopian rift highlands, where rainfall is concentrated in a single July-August peak. High average yields and erosion rates (800 ± 150 t/km 2 a, 0.29 ± 0.05 mm/a) partly reflect anthropically-accelerated erosion caused by deforestation and intensive land use, and cannot be extrapolated far in the past. Erosion patterns may have changed repeatedly during Quaternary climatic oscillations, and possibly also in the longer term during the multistage rift-related events which, since impingement of the Afar plume and eruption of flood basalts in the Oligocene, caused elevated topography and monsoonal climate in Ethiopia.

  20. Patient doses in interventional cardiology procedures in Sudan.

    PubMed

    Ahmed, Nada A; Ibraheem, S B; Habbani, F I

    2013-01-01

    Radiation doses delivered to 461 patients were measured during the period of 12 months in a hospital in Khartoum, Sudan. Kerma Area Product, Cumulative Kerma and fluoroscopy time were registered during four selected procedures, namely coronary angiography (CA), percutaneous transluminal coronary angioplasty (PTCA), percutaneous transvenous mitral commissurotomy (PTMC) and pacemaker. For CA, PTCA, PTMC and pacemaker the mean and median kerma area product values in gray centimeter square were found to be (20, 17.9), (56.5, 50.3), (21.6, 19.6) and (15.3, 9.6), respectively. The obtained results for mean and median cumulative kerma in milli gray were (143.7, 120.5), (418.4, 371.4), (119.8, 102) and (88.7, 59.8) as measured for CA, PTCA, PTMC and pacemaker, respectively. The mean and median total fluoroscopy time in minutes were (5.2, 3.39), (17.6, 14.8), (18, 15) and (10.2, 7.16) as registered for CA, PTCA, PTMA and pacemaker, respectively. Maximum skin dose was estimated for 13 patients during PTCA and CA procedures. Dose exceeded 2 Gy in PTCA for one patient. In comparison with the guidelines for coronary examinations suggested by SENTINEL Consortium, a higher fluoroscopy time for PTCA procedure is reported in this study. It is realised that proper selection of irradiation area, technique modes, fluoroscopy time and conducting special training on radiation protection to the operators are the main factors for potential optimisation. PMID:22791837

  1. Prioritizing maternal and child health in independent South Sudan.

    PubMed

    Rai, Rajesh Kumar; Ramadhan, Ally Ahmed; Tulchinsky, Theodore Herzl

    2012-08-01

    With its independence secured on 9th July 2011, the Republic of South Sudan faces a daunting task to improve public health and primary care in one of the poorest countries in the world. Very high maternal and child mortality rates must be a major concern for the new national government and for the many international agencies working in the country. Poor maternal health outcomes are primarily due to poor prenatal, delivery and post natal care services in health facilities, coupled with low literacy, widespread poverty, and poor nutrition among the general population. Child mortality is the result of widespread malnutrition, pneumonia, malaria, vaccine preventable diseases and diarrheal diseases. National responses to HIV and AIDS with international assistance have been encouraging with relatively low rates of infection. This paper explores barriers and identifies opportunities available to work toward achieving the targets for Millennium Development Goals (MDGs) 5 and 4 to reduce maternal mortality from its current rate of 2,054 deaths per 100,000 live births, and child mortality (currently 135 deaths per 1,000 live births) respectively in the new nation. National and international organizations have a social responsibility to mobilize efforts to focus on maternal, child health and nutrition issues targeting the worst affected regions for improving access to primary care and obstetrical services. Initiatives are needed to build up community access to primary care with a well supervised community health workers program, as well as training mid level management capacity with higher levels of funding from national and international sources to promote public health than current in the new republic. PMID:21959924

  2. Bacteriological quality of drinking water in Nyala, South Darfur, Sudan.

    PubMed

    Abdelrahman, Amira Ahmed; Eltahir, Yassir Mohammed

    2011-04-01

    The objective of this study was to determine the bacterial contaminations in drinking water in Nyala city, South Darfur, Sudan with special reference to the internally displaced people camps (IDPs). Two hundred and forty water samples from different sites and sources including bore holes, hand pumps, dug wells, water points, water reservoir and household storage containers were collected in 2009. The most probable number method was used to detect and count the total coliform, faecal coliform and faecal enterococci. Results revealed that the three indicators bacteria were abundant in all sources except water points. Percentages of the three indicators bacteria count above the permissible limits for drinking water in all samples were 46.4% total coliform, 45.2% faecal coliform and 25.4% faecal enterococci whereas the highest count of the indicators bacteria observed was 1,600 U/100 ml water. Enteric bacteria isolated were Escherichia coli (22.5%), Enterococcus faecalis (20.42%), Klebsiella (15.00%), Citrobacter (2.1%) and Enterobacter (3.33%). The highest contamination of water sources was observed in household storage containers (20%) followed by boreholes (11.25%), reservoirs (6.24%), hand pumps (5.42%) and dug wells (2.49%). Contamination varied from season to season with the highest level in autumn (18.33%) followed by winter (13.75%) and summer (13.32%), respectively. All sources of water in IDP camps except water points were contaminated. Data suggested the importance of greater attention for household contamination, environmental sanitation control and the raise of awareness about water contamination. PMID:20480392

  3. A New Model for Management of Mycetoma in the Sudan

    PubMed Central

    Fahal, Ahmed; Mahgoub, El Sheikh; EL Hassan, Ahmed Mohamed; Abdel-Rahman, Manar Elsheikh; Alshambaty, Yassir; Hashim, Ahmed; Hago, Ali; Zijlstra, Eduard E.

    2014-01-01

    Patients with mycetoma usually present late with advanced disease, which is attributed to lack of medical and health facilities in endemic areas, poor health education and low socio-economic status. With this background, an integrated patient management model at the village level was designed to address the various problems associated with mycetoma. The model was launched in an endemic village in the Sudan, between 2010 and 2013. This model is described in a prospective, descriptive, community-based study, aimed to collect epidemiological, ecological, and clinical data and to assess knowledge, attitude and practice (KAP) in order to design effective and efficient management measures. In this study, the prevalence of mycetoma was 14.5 per 1,000 inhabitants. The patients were farmers, housewives and children of low socio-economic status, and no obvious risk group was detected. All had surgery performed in a mobile surgical unit in the village which encouraged patients to present early with small early lesion leading to a good clinical outcome. The close contact with the Acacia tree thorns, animals and animal dung, walking bare footed and practising poor hygiene may all have contributed to the development of mycetoma in the village. Knowledge of mycetoma was poor in 96.3% of the study population, 70% had appropriate attitudes and beliefs towards interaction with mycetoma patients and treatment methods, and 49% used satisfactory or good practices in the management of mycetoma. Knowledge and practices on mycetoma were found to be significantly associated with age. Based on the KAP and epidemiological data, several health education sessions were conducted in the village for different target groups. The integrated management approach adopted in this study is unique and appeared successful and seems suitable as an immediate intervention. While for the longer term, establishment of local health facilities with trained health staff remains a priority. PMID:25356640

  4. Determination of banned Sudan dyes in food samples by molecularly imprinted solid phase extraction-high performance liquid chromatography.

    PubMed

    Baggiani, Claudio; Anfossi, Laura; Baravalle, Patrizia; Giovannoli, Cristina; Giraudi, Gianfranco; Barolo, Claudia; Viscardi, Guido

    2009-10-01

    A method for molecularly imprinted SPE of banned Sudan azo-dyes from food samples was investigated. The molecularly imprinted polymer was obtained by suspension polymerization using 1-(4-chlorophenyl)azonaphthalen-2-ol as the mimic template. The molecular recognition properties of imprinted beads were evaluated for use as a SPE sorbent, in order to develop a selective extraction protocol for the Sudan class of dyes. The optimized extraction protocol resulted in a reliable molecularly imprinted SPE (MISPE) method suitable for HPLC analysis. It was selective for the main analyte, Sudan I, and the related azo-dyes Sudan II, III, IV, Sudan Red B, and Sudan Red 7B, while the permitted azo-dyes Allura Red AC, Neococcin, and Sunset Yellow FCF were not extracted. The method was tested for Sudan I, II, III, and IV in five different food samples (hot chilli pepper, hot chilli tomato sauce, sausage, tomato sauce, and hard boiled egg yolk) at three concentration levels (15, 100, and 300 microg/g). It demonstrated itself to be insensitive to the presence of different complex matrices, precise, accurate, and with good recovery rates (85-101%). The LOD and LOQ were satisfactory for most analytical determinations. PMID:19722173

  5. Gender differences in the prevalence and determinants of tobacco use among school-aged adolescents (11 – 17 years) in Sudan and South Sudan

    PubMed Central

    Atari, Dominic Odwa

    2014-01-01

    Introduction Tobacco use is one of the leading and preventable causes of global morbidities and premature mortalities. The study explores gender differences in the prevalence and determinants of tobacco use among school-aged adolescents (11-17years) in Sudan and South Sudan. Methods The study utilized the national Global Youth Tobacco Survey (GYTS) data collected in 2005 for Sudan (4,277 unweighted; 131,631 weighted). Univariate and bivariate analyses were conducted to examine the associations between the dependent (tobacco use status) and independent variables. Logistic regression analyses were performed to identify the key factors which influence tobacco consumption among adolescents in the 2 Sudans for ever cigarette users, current cigarette users, and users of noncigarette tobacco products. Results There were significant gender differences in the prevalence of ever cigarette users (21.8%; male=13.1%, female=6.5%, p<0.05) and current cigarette users (6.9%; male=4.9%, female = 1.3%, p<0.05) but not among users of noncigarette tobacco products (14.7%; male=6.8%, female=6.1%). Adolescent tobacco use was significantly associated with availability of monthly income or allowance, exposure to tobacco industry promotions, and tobacco-use behavior of familial relations. Knowledge about the harmful effects of secondhand smoke was related with decreased likelihood of tobacco use. Conclusion School programs that focus on health messages alone may not work for the adolescent population. Legislations that ban all types of tobacco advertisements, promotions, and sponsorships among adolescents are needed in the 2 countries. PMID:25404978

  6. Risk Factors for Sustained Cholera Transmission, Juba County, South Sudan, 2014

    PubMed Central

    Ujjiga, Thomas T.A.; Mogga, Juma J.H.; Othwonh, Thabo O.; Mutonga, David; Kone-Coulibaly, Asta; Ali, Masood; Mpairwe, Allan M.; Abdinasir, Abubaker; Abdi, Mohamed A.; Yoti, Zabulon; Olushayo, Olu; Nyimol, Pinyi; Lul, Riek; Lako, Richard L.; Rumunu, John

    2015-01-01

    We conducted a case–control study to identify risk factors for the 2014 cholera outbreak in Juba County, South Sudan. Illness was associated with traveling or eating away from home; treating drinking water and receiving oral cholera vaccination were protective. Oral cholera vaccination should be used to complement cholera prevention efforts. PMID:26402715

  7. An analysis of mortality trends among refugee populations in Somalia, Sudan, and Thailand*

    PubMed Central

    Toole, M. J.; Waldman, R. J.

    1988-01-01

    A review of mortality data from refugee camps in Thailand (1979-80), Somalia (1980-85), and Sudan (1984-85) indicates that crude mortality rates (CMRs) were up to 40 times higher than those for the non-refugee populations in the host countries. In eastern Sudan, approximately 5% of the population of eight camps died in the first 3 months of the emergency and daily CMRs as high as 14 per 10 000 were reported. These rates dropped to values comparable with those of the host country within 6 weeks in the Thai camps; however, in Somalia and Sudan this process took 12 months. Mortality rates among under-5-year olds in the early phases, which were as high as 32.6 per 10 000 per day, are six times greater than those in the world's least developed countries during non-emergency times. Among severely undernourished children in one camp in Sudan, the death rate reached 114 per 10 000 per day. Acute respiratory infections, diarrhoeal diseases, malaria, measles, and undernutrition were the causes of most reported deaths, the majority of which could have been prevented by adequate food rations, clean water, measles immunization, and an oral rehydration programme. PMID:3260831

  8. 76 FR 69612 - Amendment to the International Traffic in Arms Regulations: Sudan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ...The Department of State is amending the International Traffic in Arms Regulations to include the Republic of the Sudan as a proscribed destination, pursuant to a United Nations Security Council arms embargo, and to clarify that this policy does not apply to the Republic of South...

  9. 76 FR 63629 - Designation of Republic of South Sudan for Temporary Protected Status

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-13

    ... SECURITY Citizenship and Immigration Services RIN 1615-ZB08 Designation of Republic of South Sudan for Temporary Protected Status AGENCY: U.S. Citizenship and Immigration Services, Department of Homeland... register and to apply for TPS and Employment Authorization Documents (EADs) with U.S. Citizenship...

  10. 78 FR 8360 - Addition of South Sudan to the Restricted Destinations List

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-06

    ... power program; however, South Sudan does have the need for radioactive sources for legitimate industrial, medical, and research purposes in support of important economic and commercial development projects... that this final rule will not have a significant economic impact on a substantial number of...

  11. A Basic Hybrid Library Support Model to Distance Learners in Sudan

    ERIC Educational Resources Information Center

    Abdelrahman, Omer Hassan

    2012-01-01

    Distance learning has flourished in Sudan during the last two decades; more and more higher education institutions offer distance learning programmes to off-campus students. Like on-campus students, distance learners should have access to appropriate library and information support services. They also have specific needs for library and…

  12. The Naivasha Language Policy: The Language of Politics and the Politics of Language in the Sudan

    ERIC Educational Resources Information Center

    Abdelhay, Ashraf Kamal; Makoni, Busi; Makoni, Sinfree Bullock

    2011-01-01

    This article provides a textual analysis of the Naivasha language provisions in Sudan in an attempt to explore how political discourse is manifested in each policy statement. Using Critical Discourse Analysis (CDA) as an analytic and interpretive framework, the article argues that the Naivasha language provisions as political discourse are shaped…

  13. Feasibility of health systems strengthening in South Sudan: a qualitative study of international practitioner perspectives

    PubMed Central

    Jones, Abigail; Legido-Quigley, Helena

    2015-01-01

    Objective To explore the feasibility of health systems strengthening from the perspective of international healthcare implementers and donors in South Sudan. Design A qualitative interview study, with thematic analysis using the WHO health system building blocks framework. Setting South Sudan. Participants 17 health system practitioners, working for international agencies in South Sudan, were purposively sampled for their knowledge and experiences of health systems strengthening, services delivery, health policy and politics in South Sudan. Results Participants universally reported the health workforce as insufficient and of low capacity and service delivery as poor, while access to medicines was restricted by governmental lack of commitment in undertaking procurement and supply. However, progress was clear in improved county health department governance, health management information system functionality, increased health worker salary harmonisation and strengthened financial management. Conclusions Resurgent conflict and political tensions have negatively impacted all health system components and maintaining or continuing health system strengthening has become extremely challenging. A coordinated approach to balancing humanitarian need particularly in conflict-affected areas, with longer term development is required so as not to lose improvements gained. PMID:26700280

  14. Research On: Motivation to Learn English among College Students in Sudan

    ERIC Educational Resources Information Center

    Humaida, Ibrahim Abdelrahim Ibrahim

    2012-01-01

    This research was conducted to achieve the following objectives: to examine motivation to learn English language among students of faculty of arts, Islamic University-Sudan, to find out if there were significant statistical differences on motivation scores related to both student level and age. To pursue these objectives, the researcher used the…

  15. Genetic Diversity of Schistosoma haematobium Eggs Isolated from Human Urine in Sudan.

    PubMed

    Quan, Juan-Hua; Choi, In-Wook; Ismail, Hassan Ahmed Hassan Ahmed; Mohamed, Abdoelohab Saed; Jeong, Hoo-Gn; Lee, Jin-Su; Hong, Sung-Tae; Yong, Tai-Soon; Cha, Guang-Ho; Lee, Young-Ha

    2015-06-01

    The genetic diversity of Schistosoma haematobium remains largely unstudied in comparison to that of Schistosoma mansoni. To characterize the extent of genetic diversity in S. haematobium among its definitive host (humans), we collected S. haematobium eggs from the urine of 73 infected schoolchildren at 5 primary schools in White Nile State, Sudan, and then performed a randomly amplified polymorphic DNA marker ITS2 by PCR-RFLP analysis. Among 73 S. haematobium egg-positive cases, 13 were selected based on the presence of the S. haematobium satellite markers A4 and B2 in their genomic DNA, and used for RFLP analysis. The 13 samples were subjected to an RFLP analysis of the S. haematobium ITS2 region; however, there was no variation in size among the fragments. Compared to the ITS2 sequences obtained for S. haematobium from Kenya, the nucleotide sequences of the ITS2 regions of S. haematobium from 4 areas in Sudan were consistent with those from Kenya (> 99%). In this study, we demonstrate for the first time that most of the S. haematobium population in Sudan consists of a pan-African S. haematobium genotype; however, we also report the discovery of Kenyan strain inflow into White Nile, Sudan. PMID:26174820

  16. 3 CFR - Continuation of the National Emergency With Respect to Sudan

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 3 The President 1 2010-01-01 2010-01-01 false Continuation of the National Emergency With Respect... of the National Emergency With Respect to Sudan On November 3, 1997, by Executive Order 13067, the... November 3, 1997, as expanded on April 26, 2006, and with respect to which additional steps were taken...

  17. 3 CFR - Continuation of the National Emergency With Respect to Sudan

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 3 The President 1 2011-01-01 2011-01-01 false Continuation of the National Emergency With Respect... of the National Emergency With Respect to Sudan On November 3, 1997, by Executive Order 13067, the... November 3, 1997, as expanded on April 26, 2006, and with respect to which additional steps were taken...

  18. 31 CFR 538.205 - Prohibited exportation and reexportation of goods, technology, or services to Sudan.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Prohibited exportation and reexportation of goods, technology, or services to Sudan. 538.205 Section 538.205 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY SUDANESE SANCTIONS...

  19. Geologic assessment of the fossil energy and geothermal potential of the Sudan

    SciTech Connect

    Setlow, L.W.

    1983-01-01

    This preliminary report provides geological input to the consideration of appropriate activities that can enhance the exploration and development of fossil-fuel and possible geothermal energy resources of the Sudan, and is based on study of available literature in early 1982. 59 references, 16 figures, 7 tables.

  20. Study of Characteristics, Attitudes and Opinions of the Students in the College of Agriculture in Sudan.

    ERIC Educational Resources Information Center

    Bannaga, Ali Mohayad

    In examining characteristics, attitudes, and opinions of the students in the College of Agriculture, University of Khartoum, in the Sudan, this study focused on eight independent variables: years in the College of Agriculture, location of permanent home, size of home town, length of hostel living experience, father's occupation, number of living…

  1. Examining the Contemporary Status of an Education System: The Case of the Republic of South Sudan

    ERIC Educational Resources Information Center

    Banraba, Boboya James Edimond

    2015-01-01

    This paper attempts to examine the contemporary status of an education system. The paper takes the case of the Republic of South Sudan. The key issues the paper will examine are the education enrollment and completion rates while paying particular attention to inequalities in both access and quality among racial or ethnic groups, males and…

  2. The Sociolinguistics of Nationalism in the Sudan: The Politicisation of Arabic and the Arabicisation of Politics

    ERIC Educational Resources Information Center

    Abdelhay, Ashraf; Makoni, Busi; Makoni, Sinfree; Mugaddam, Abdel Rahim

    2011-01-01

    This monograph describes the historiography of language ideologies that led to the politicisation of Arabic and the Arabicisation of politics in the Sudan, starting from British colonial rule until the Comprehensive Peace Agreement that was a precursor to the separation of the South as an independent state. The monograph shows that the…

  3. Adult Literacy in Africa--Nigeria, Rhodesia, South Africa, Sudan, Tanzania. Literacy Bibliographies 23.

    ERIC Educational Resources Information Center

    International Inst. for Adult Literacy Methods, Teheran (Iran).

    Approximately 200 items are listed in this bibliography of materials pertaining to adult literacy in Nigeria, Rhodesia, South Africa, the Sudan, and Tanzania. The listed materials are categorized according to country and deal with a variety of topics, including the following: (1) adult education and adaptation to change in Nigeria; (2) adult…

  4. Flow injection chemiluminescence determination of sudan I in hot chilli sauce.

    PubMed

    Liu, Yanhong; Song, Zhenghua; Dong, Faxin; Zhang, Lin

    2007-02-01

    A chemiluminescence method based on the luminol-H2O2 system with flow injection technology was proposed for the determination of sudan I in hot chilli sauce. It was found that sudan I could enhance chemiluminescence intensity generated from the luminol-H2O2 system. The increment of chemiluminescence intensity was proportional to the concentration of sudan I, giving a calibration graph linear over the concentration from 10 pg mL-1 to 7 ng mL-1 (R 2 = 0.9980) with the detection limit of 3 pg mL-1 (3sigma) and the quantification limit of 7.5 pg mL-1. At a flow rate of 2.0 mL min-1, one analysis cycle, including sampling and washing, could be accomplished in 60 s with a relative standard deviation of <5.0%. The method has been applied successfully to the determination of sudan I in Pixian douban, Golden Mark guilin chilli sauce, and Golden Mark satay sauce, and the recovery was 90.6-110.0%. PMID:17263450

  5. Civic Education and Peacebuilding: Examples from Iraq and Sudan. Special Report 254

    ERIC Educational Resources Information Center

    Levine, Daniel H.; Bishai, Linda S.

    2010-01-01

    Between 2006 and 2010, the United States Institute of Peace developed several civic education programs for Iraq and Sudan as part of broader efforts to promote postconflict stability and development and help prevent a return to violence. This report describes those programs after first examining the conceptual bases for civic education and how…

  6. South Sudan: Stakeholders' Views of Technical and Vocational Education and Training and a Framework for Action

    ERIC Educational Resources Information Center

    Atari, Dominic Odwa; McKague, Kevin

    2015-01-01

    The Republic of South Sudan, recently emerging from the longest civil war in contemporary African history, has set goals towards post-conflict reconstruction in many areas of social services. However, the educational infrastructure continues to struggle, and many stakeholders in government and international and local organisations are not…

  7. 76 FR 68053 - Continuation of the National Emergency With Respect to Sudan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-02

    ... Register and transmitted to the Congress. (Presidential Sig.) THE WHITE HOUSE, November 1, 2011. [FR Doc..., pursuant to the International Emergency Economic Powers Act (50 U.S.C. 1701-1706), to deal with the unusual... President determined that the conflict in Sudan's Darfur region posed an unusual and extraordinary threat...

  8. Southern Rains

    Atmospheric Science Data Center

    2014-05-15

    ...   View Larger image Vigorous vegetation growth in the Southern United States after heavy rains fell during April and ... for atmospheric scattering and absorption effects, and use plant canopy structural models to determine the partitioning of solar ...

  9. Continent-scale strike-slip on a low-angle fault beneath New Zealand's Southern Alps: Implications for crustal thickening in oblique collision zones

    NASA Astrophysics Data System (ADS)

    Lamb, Simon; Smith, Euan; Stern, Tim; Warren-Smith, Emily

    2015-09-01

    New Zealand's Southern Alps lie adjacent to the continent-scale dextral strike-slip Alpine Fault, on the boundary between the Pacific and Australian plates. We show with a simple 2-D model of crustal balancing that the observed crustal root and erosion (expressed as equivalent crustal shortening) is up to twice that predicted by the orthogonal plate convergence since ˜11 Ma, and even since ˜23 Ma when the Alpine Fault formed. We consider two explanations for this, involving a strong component of motion along the length of the plate-boundary zone. Geophysical data indicate that the Alpine Fault has a listric geometry, flattening at mid crustal levels, and has accommodated sideways underthrusting of Australian plate crust beneath Pacific plate crust. The geometry of the crustal root, together with plate reconstructions, requires the underthrust crust to be the hyperextended part of an asymmetric rift system which formed over 500 km farther south during the Eocene—the narrow remnant part today forms the western margin of the Campbell Plateau. At ˜10 Ma, the hyperextended margin underwent shallow subduction in the Puysegur subduction zone, and then was dragged over 300 km along the length of the Southern Alps beneath a low-angle (<20°) section of the Alpine Fault. We speculate that prior to 10 Ma, more distributed lower crustal shortening and thickening occurred beneath the Southern Alps, accommodating southward extrusion of continental crust in the northern part of the plate boundary zone, providing a mechanism for clockwise rotation of the Hikurangi margin.

  10. Phytoplankton size structure in the southern Bay of Bengal modified by the Summer Monsoon Current and associated eddies: Implications on the vertical biogenic flux

    NASA Astrophysics Data System (ADS)

    Jyothibabu, R.; Vinayachandran, P. N.; Madhu, N. V.; Robin, R. S.; Karnan, C.; Jagadeesan, L.; Anjusha, A.

    2015-03-01

    The present study combines field and satellite observations to investigate how hydrographical transformations influence phytoplankton size structure in the southern Bay of Bengal during the peak Southwest Monsoon/Summer Monsoon (July-August). The intrusion of the Summer Monsoon Current (SMC) into the Bay of Bengal and associated changes in sea surface chemistry, traceable eastward up to 90°E along 8°N, seems to influence biology of the region significantly. Both in situ and satellite (MODIS) data revealed low surface chlorophyll except in the area influenced by the SMC. During the study period, two well-developed cyclonic eddies (north) and an anti-cyclonic eddy (south), closely linked to the main eastward flow of the SMC, were sampled. Considering the capping effect of the low-saline surface water that is characteristic of the Bay of Bengal, the impact of the cyclonic eddy, estimated in terms of enhanced nutrients and chlorophyll, was mostly restricted to the subsurface waters (below 20 m depth). Conversely, the anti-cyclonic eddy aided by the SMC was characterized by considerably higher nutrient concentration and chlorophyll in the upper water column (upper 60 m), which was contrary to the general characteristic of such eddies. Albeit smaller phytoplankton predominated the southern Bay of Bengal (60-95% of the total chlorophyll), the contribution of large phytoplankton was double in the regions influenced by the SMC and associated eddies. Multivariate analysis revealed the extent to which SMC-associated eddies spatially influence phytoplankton community structure. The study presents the first direct quantification of the size structure of phytoplankton from the southern Bay of Bengal and demonstrates that the SMC-associated hydrographical ramifications significantly increase the phytoplankton biomass contributed by larger phytoplankton and thereby influence the vertical opal and organic carbon flux in the region.

  11. Disability associated with exposure to traumatic events: results from a cross-sectional community survey in South Sudan

    PubMed Central

    2013-01-01

    Background There is a general lack of knowledge regarding disability and especially factors that are associated with disability in low-income countries. We aimed to study the overall and gender-specific prevalence of disability, and the association between exposure to traumatic events and disability in a post-conflict setting. Methods We conducted a cross-sectional community based study of four Greater Bahr el Ghazal States, South Sudan (n = 1200). The Harvard Trauma Questionnaire (HTQ) was applied to investigate exposure to trauma events. Disability was measured using the Washington Group Short Measurement Set on Disability, which is an activity-based scale derived from the WHO’s International Classification of Disability, Functioning and Health. Results The estimated prevalence of disability (with severe difficulty) was 3.6% and 13.4% for disability with moderate difficulties. No gender differences were found in disability prevalence. Almost all participants reported exposure to at least one war-related traumatic event. The result of a hierarchical regression analysis showed that, for both men and women, exposure to traumatic events, older age and living in a polygamous marriage increased the likelihood of having a disability. Conclusions The finding of association between traumatic experience and disability underlines the precariousness of the human rights situation for individuals with disability in low-income countries. It also has possible implications for the construction of disability services and for the provision of health services to individuals exposed to traumatic events. PMID:23672785

  12. Late Holocene Environmental Change at Amara West: A New Kingdom Town on the Desert Nile in Northern Sudan

    NASA Astrophysics Data System (ADS)

    Spencer, Neal; Woodward, Jamie; Macklin, Mark; Dalton, Matthew

    2014-05-01

    Amara West is a well-preserved town of the late New Kingdom downstream of Sai Island in Northern Sudan. The town has being identified as the seat of the pharaonic administration of Kush (Upper Nubia) in the Ramesside Period (c. 1306-1070 BC). This region fell under Egyptian control after about 1500 BC. The modern Nile (flowing eastwards in this reach) lies to the south of the town and a well preserved palaeochannel lies immediately to the north. Following the Egypt Exploration Society excavations of 1938-39 and 1947-48, it was argued that the ancient town was once located upon an island in the Nile. Renewed archaeological excavations allied to geomorphological work on the ancient river environment are attempting to establish the nature of the local and regional landscape before, during, and after the occupation of the town. This paper presents new OSL and radiocarbon dates on the sedimentary fill from the palaeochannel system to establish when the channel system ceased to flow on a permanent basis. Micromorphological work on the sedimentary records within the town provide additional insights into the nature of the local environment during the period of occupation. We discuss the implications of the new palaeoenvironmental data for our understanding of Amara West and we set out the wider significance of these new geoarchaeological data.

  13. Antibody Treatment of Ebola and Sudan Virus Infection via a Uniquely Exposed Epitope within the Glycoprotein Receptor-Binding Site.

    PubMed

    Howell, Katie A; Qiu, Xiangguo; Brannan, Jennifer M; Bryan, Christopher; Davidson, Edgar; Holtsberg, Frederick W; Wec, Anna Z; Shulenin, Sergey; Biggins, Julia E; Douglas, Robin; Enterlein, Sven G; Turner, Hannah L; Pallesen, Jesper; Murin, Charles D; He, Shihua; Kroeker, Andrea; Vu, Hong; Herbert, Andrew S; Fusco, Marnie L; Nyakatura, Elisabeth K; Lai, Jonathan R; Keck, Zhen-Yong; Foung, Steven K H; Saphire, Erica Ollmann; Zeitlin, Larry; Ward, Andrew B; Chandran, Kartik; Doranz, Benjamin J; Kobinger, Gary P; Dye, John M; Aman, M Javad

    2016-05-17

    Previous efforts to identify cross-neutralizing antibodies to the receptor-binding site (RBS) of ebolavirus glycoproteins have been unsuccessful, largely because the RBS is occluded on the viral surface. We report a monoclonal antibody (FVM04) that targets a uniquely exposed epitope within the RBS; cross-neutralizes Ebola (EBOV), Sudan (SUDV), and, to a lesser extent, Bundibugyo viruses; and shows protection against EBOV and SUDV in mice and guinea pigs. The antibody cocktail ZMapp™ is remarkably effective against EBOV (Zaire) but does not cross-neutralize other ebolaviruses. By replacing one of the ZMapp™ components with FVM04, we retained the anti-EBOV efficacy while extending the breadth of protection to SUDV, thereby generating a cross-protective antibody cocktail. In addition, we report several mutations at the base of the ebolavirus glycoprotein that enhance the binding of FVM04 and other cross-reactive antibodies. These findings have important implications for pan-ebolavirus vaccine development and defining broadly protective antibody cocktails. PMID:27160900

  14. Organochlorine contaminants in blubber from stranded marine mammals collected from the Northern Oregon and Southern Washington coasts: implications for re-introducing California Condors, Gymnogyps californianus, in Oregon.

    PubMed

    Gundersen, Deke T; Duffield, Deborah A; Randall, Tina; Wintle, Nate; D'Alessandro, Dalin N; Rice, James M; Shepherdson, David

    2013-03-01

    Re-introduction of California Condors into Oregon is currently being considered, but there are concerns about the safety of potential food sources of this species. Condors are opportunistic feeders and a largely available food source for this species will be stranded marine mammal carcasses. We analyzed 37 blubber samples from 7 different marine mammal species collected from the Oregon and Southern Washington coasts for 18 organochlorine (OC) pesticides and 16 polychlorinated biphenyls (PCBs). Dichlorodiphenyldichloroethylene (DDE) was the most prevalent OC contaminant, making up more than 58 % of the total OC concentration measured. There were no significant differences in OC content between species or sexes. PMID:23275975

  15. Provenance of the Passo Feio complex, Dom Feliciano Belt: Implications for the age of supracrustal rocks of the São Gabriel Arc, southern Brazil

    NASA Astrophysics Data System (ADS)

    Lopes, Carina Graciniana; Pimentel, Marcio Martins; Philipp, Ruy Paulo; Gruber, Leonardo; Armstrong, Richard; Junges, Sergio

    2015-03-01

    The Passo Feio complex (PFC) is a sequence of metapelite, amphibolite, metavolcanic/metavolcanoclastic rocks, marble, calc-silicate rocks, quartzite and magnesium schist. It is part of the São Gabriel Terrane, a Neoproterozoic juvenile arc formed during the early stages of evolution of the Neoproterozoic Dom Feliciano Belt (DFB), in southern Brazil. This belt corresponds to the southernmost portion of the Mantiqueira Province, an important Neoproterozoic orogenic system exposed in the NNE direction along the southeastern coast of Brazil. The geotectonic significance of the original Passo Feio basin in the tectonic evolution of São Gabriel Terrene is not well understood. It has been considered as part of a passive margin sequence or as a back-arc sequence. Geochronological and isotopic data are very scarse for the Passo Feio rocks and this has hampered the better understanding of its significance in the Neoproterozoic tectonic evolution of southern Brazil. In the present study the age and significance of metasedimentary rocks of the PFC were investigated. The provenance study was carried out in four metapelite samples from the southern and northern Passo Feio complex, using U-Pb dating of detrital zircon. The results showed varied provenance patterns and zircon ages range from 3637 to 803 Ma. Paleo- and Mesoproterozoic detrital zircon grains are present in all samples, but an important Neoproterozoic population has been identified in one of them. 3.5 Ga old zircon grains form the oldest population of detrital zircon ever reported in southern Brazil. Paleoproterozoic/Archean terranes within the Rio de la Plata Craton may represent the main source of detrital sediments and this suggests that part of the Passo Feio complex might have been a passive margin sequence, developed along the northeastern margin of that paleocontinent. However, the presence of a Neoproterozoic zircon population is not consistent with derivation solely from the craton and indicates contribution from younger sources, such as the Neoproterozoic São Gabriel Arc itself. This Neoproterozoic zircon population with ages ranging from 948 to 803 Ma, suggests that the onset of the magmatic/tectonic evolution of the São Gabriel Arc might have started as early ca. 0.95 Ma.

  16. Ignimbrite flare-up and deformation in the southern Sierra Madre Occidental, western Mexico: Implications for the late subduction history of the Farallon plate

    NASA Astrophysics Data System (ADS)

    Ferrari, Luca; López-Martínez, Margarita; Rosas-Elguera, José

    2002-08-01

    The Sierra Madre Occidental (SMO) of western Mexico is one of the largest silicic volcanic provinces on Earth, but the mechanism for the generation of such a large volume of ignimbrites has never been clearly defined. We present new 40Ar/39Ar ages, geologic mapping, and structural data for the southern part of the SMO demonstrating that most of this volcanic province was built in two episodes of ignimbrite flare-up in Oligocene (31.5-28 Ma) and early Miocene (23.5-20 Ma) time, and that extensional deformation occurred mostly before the transfer of Baja California to the Pacific plate. Extensive ignimbrite successions, with 40Ar/39Ar ages clustering at ~23 and ~21 Ma, cover most of the southern SMO, thus correlating in age with ignimbrites exposed in southern Baja California and central Mexico. Grabens with a 020° to N-S orientation developed in the east almost concurrently with this volcanic episode. Half grabens and NNW striking listric normal fault systems formed at the end of middle Miocene as far as 150 km from the present coast. A belt of left-lateral transpressional structures formed along the southern boundary of the SMO during the same period. We link these magmatic and tectonic events to the evolution and dynamics of the Farallon and North America plates during the Miocene. Particularly, we propose that a first detachment of the lower part of the Farallon plate in early Miocene time produced a transient thermal event and partial melting of the crust via mafic underplating. Middle Miocene extension would be related to a second detachment event, resulting from the slowing subduction that preceded the final capture of the Magdalena microplate by the Pacific plate at 12.5 Ma. Transpression at the southernmost end of the SMO occurred along the inland projection of the Magdalena-Cocos plate boundary and may be explained by a difference in subduction rate and by a temporal convergence between the two plates in the eve of the end of subduction of the Magdalena plate.

  17. Malaria control in South Sudan, 2006–2013: strategies, progress and challenges

    PubMed Central

    2013-01-01

    Background South Sudan has borne the brunt of years of chronic warfare and probably has the highest malaria burden in sub-Saharan Africa. However, effective malaria control in post-conflict settings is hampered by a multiplicity of challenges. This manuscript reports on the strategies, progress and challenges of malaria control in South Sudan and serves as an example epitome for programmes operating in similar environments and provides a window for leveraging resources. Case description To evaluate progress and challenges of the national malaria control programme an in-depth appraisal was undertaken according to the World Health Organization standard procedures for malaria programme performance review. Methodical analysis of published and unpublished documents on malaria control in South Sudan was conducted. To ensure completeness, findings of internal thematic desk assessments were triangulated in the field and updated by external review teams. Discussion and evaluation South Sudan has strived to make progress in implementing the WHO recommended malaria control interventions as set out in the 2006–2013 National Malaria Strategic Plan. The country has faced enormous programmatic constraints including infrastructure, human and financial resource and a weak health system compounded by an increasing number of refugees, returnees and internally displaced people. The findings present a platform on which to tailor an evidence-based 2014–2018 national malaria strategic plan for the country and a unique opportunity for providing a model for countries in a post-conflict situation. Conclusions The prospects for effective malaria control and elimination are huge in South Sudan. Nevertheless, strengthened coordination, infrastructure and human resource capacity, monitoring and evaluation are required. To achieve all this, allocation of adequate local funding would be critical. PMID:24160336

  18. Hepatitis C Virus Epidemiology in Djibouti, Somalia, Sudan, and Yemen: Systematic Review and Meta-Analysis

    PubMed Central

    Chaabna, Karima; Kouyoumjian, Silva P.; Abu-Raddad, Laith J.

    2016-01-01

    Objectives To characterize hepatitis C virus (HCV) epidemiology and assess country-specific population-level HCV prevalence in four countries in the Middle East and North Africa (MENA) region: Djibouti, Somalia, Sudan, and Yemen. Methods Reports of HCV prevalence were systematically reviewed as per PRISMA guidelines. Pooled HCV prevalence estimates in different risk populations were conducted when the number of measures per risk category was at least five. Results We identified 101 prevalence estimates. Pooled HCV antibody prevalence in the general population in Somalia, Sudan and Yemen was 0.9% (95% confidence interval [95%CI]: 0.3%–1.9%), 1.0% (95%CI: 0.3%–1.9%) and 1.9% (95%CI: 1.4%–2.6%), respectively. The only general population study from Djibouti reported a prevalence of 0.3% (CI: 0.2%–0.4%) in blood donors. In high-risk populations (e.g., haemodialysis and haemophilia patients), pooled HCV prevalence was 17.3% (95%CI: 8.6%–28.2%) in Sudan. In Yemen, three studies of haemodialysis patients reported HCV prevalence between 40.0%-62.7%. In intermediate-risk populations (e.g.. healthcare workers, in patients and men who have sex with men), pooled HCV prevalence was 1.7% (95%CI: 0.0%–4.9%) in Somalia and 0.6% (95%CI: 0.4%–0.8%) in Sudan. Conclusion National HCV prevalence in Yemen appears to be higher than in Djibouti, Somalia, and Sudan as well as most other MENA countries; but otherwise prevalence levels in this subregion are comparable to global levels. The high HCV prevalence in patients who have undergone clinical care appears to reflect ongoing transmission in clinical settings. HCV prevalence in people who inject drugs remains unknown. PMID:26900839

  19. Anionic surfactant linear alkylbenzene sulfonates (LAS) in sediments from the Gulf of Gda?sk (southern Baltic Sea, Poland) and its environmental implications.

    PubMed

    Hampel, Miriam; Mauffret, Aourell; Pazdro, Ksenia; Blasco, Julian

    2012-10-01

    Linear alkylbenzene sulfonate (LAS) is a group of anionic surfactants employed in the formulation of laundry and cleaning products, with a global production rate of 4 million metric tons. Sediments from the Polish coast of the southern Baltic Sea were collected at ten stations. Total LAS concentrations, measured by high-performance liquid chromatography, were between 0.04 and 0.72 mg LASkg(-1) dry weight. Highest LAS concentrations were found in suspended matter collected from the Vistula River, sediment collected close to the Vistula River mouth and from the Gda?sk Deep, known as the depositional area. With the obtained environmental LAS concentrations, a risk assessment for this surfactant has been carried out, based on publicly available acute and chronic toxicity data in target organisms. The results indicated that LAS could pose a low risk for the existing benthic community applying worst case scenario assessment. This is the first time that levels of LAS have been measured in environmental samples of the southern Baltic Sea. PMID:22006264

  20. Carbonate saturation state of surface waters in the Ross Sea and Southern Ocean: controls and implications for the onset of aragonite undersaturation

    NASA Astrophysics Data System (ADS)

    DeJong, H. B.; Dunbar, R. B.; Mucciarone, D.; Koweek, D. A.

    2015-12-01

    Predicting when surface waters of the Ross Sea and Southern Ocean will become undersaturated with respect to biogenic carbonate minerals is challenging in part due to the lack of baseline high-resolution carbon system data. Here we present ~ 1700 surface total alkalinity measurements from the Ross Sea and along a transect between the Ross Sea and southern Chile from the austral autumn (February-March 2013). We calculate the saturation state of aragonite (ΩAr) and calcite (Ω Ca) using measured total alkalinity and pCO2. In the Ross Sea and south of the Polar Front, variability in carbonate saturation state (Ω) is mainly driven by algal photosynthesis. Freshwater dilution and calcification have minimal influence on Ω variability. We estimate an early spring surface water ΩAr value of ~ 1.2 for the Ross Sea using a total alkalinity-salinity relationship and historical pCO2 measurements. Our results suggest that the Ross Sea is not likely to become undersaturated with respect to aragonite until the year 2070.

  1. Carbonate saturation state of surface waters in the Ross Sea and Southern Ocean: controls and implications for the onset of aragonite undersaturation

    NASA Astrophysics Data System (ADS)

    DeJong, H. B.; Dunbar, R. B.; Mucciarone, D. A.; Koweek, D. A.

    2015-06-01

    Predicting when surface waters of the Ross Sea and Southern Ocean will become undersaturated with respect to biogenic carbonate minerals is challenging in part due to the lack of baseline high resolution carbon system data. Here we present ~ 1700 surface total alkalinity measurements from the Ross Sea and along a transect between the Ross Sea and southern Chile from the austral autumn (February-March 2013). We calculate the saturation state of aragonite (ΩAr) and calcite (ΩCa) using measured total alkalinity and pCO2. In the Ross Sea and south of the Polar Front, variability in carbonate saturation state (Ω) is mainly driven by algal photosynthesis. Freshwater dilution and calcification have minimal influence on Ω variability. We estimate an early spring surface water ΩAr value of ~ 1.2 for the Ross Sea using a total alkalinity-salinity relationship and historical pCO2 measurements. Our results suggest that the Ross Sea is not likely to become undersaturated with respect to aragonite until the year 2070.

  2. Hyalomma ticks on northward migrating birds in southern Spain: Implications for the risk of entry of Crimean-Congo haemorrhagic fever virus to Great Britain.

    PubMed

    England, Marion E; Phipps, Paul; Medlock, Jolyon M; Atkinson, Peter M; Atkinson, Barry; Hewson, Roger; Gale, Paul

    2016-06-01

    Crimean-Congo haemorrhagic fever virus (CCHFV) is a zoonotic virus transmitted by Hyalomma ticks, the immature stages of which may be carried by migratory birds. In this study, a total of 12 Hyalomma ticks were recovered from five of 228 migratory birds trapped in Spring, 2012 in southern Spain along the East Atlantic flyway. All collected ticks tested negative for CCHFV. While most birds had zero Hyalomma ticks, two individuals had four and five ticks each and the statistical distribution of Hyalomma tick counts per bird is over-dispersed compared to the Poisson distribution, demonstrating the need for intensive sampling studies to avoid underestimating the total number of ticks. Rates of tick exchange on migratory birds during their northwards migration will affect the probability that a Hyalomma tick entering Great Britain is positive for CCHFV. Drawing on published data, evidence is presented that the latitude of a European country affects the probability of entry of Hyalomma ticks on wild birds. Further data on Hyalomma infestation rates and tick exchange rates are required along the East Atlantic flyway to further our understanding of the origin of Hyalomma ticks (i.e., Africa or southern Europe) and hence the probability of entry of CCHFV into GB. PMID:27232135

  3. Women's income generation activities in Merowe Province, Northern State, Sudan.

    PubMed

    Pitamber, S; Osama, S

    1994-06-01

    Merowe province in rural northern Sudan has been divided into three local government council areas: Merowe, Karima, and Ed Debba. A government program was instituted to increase the welfare of residents and food production. A baseline survey of 490 respondents was conducted in order to ascertain how illiterate women viewed development in the area and to provide useful information for program design and implementation. Women from 24 villages were administered questionnaires, observed in their daily activities, and engaged in discussion in a local meeting place. Discussions were also held with members of the local Popular Committee. Demographic information was very sketchy about age, and 48% had no formal education in writing and reading. General reading and writing skills of the remainder were very poor. There were 500 female children and 502 male children, and the sex ratio varied among the 3 council areas. 52% were married and 14% were divorced or widowed and living with relatives. The average monthly income was from Ls. 700 to Ls. 3000 based on reports from only 59.3% of respondents. Most of the women had skills in food processing and 25.7% were skilled in handicrafts. Water was obtained primarily from local wells and not decontaminated before use. Pit latrines were the standard. One bathing facility was available in the compound for the entire council area. Health units were either in each village or within 20-30 minutes walk. Child mortality was 4.3% in Merowe province. 77 children 0-5 years old died out of a total of 1002 live births. Life expectancy was 41-50 years for women and 61-70 years for men. Cleanliness and healthful eating were observed. 58% owned no land; plots were under 5 feddans and usually half a feddan. 92.1% had no bank account and 90% had no experience with loans. 70.2% were indifferent about involvement in an income generation program. 26% were interested in part-time participation. Only 3.9% desired full-time participation. 8.6% said they wanted raw materials to produce handicrafts, and 21% said they wanted cash to raise livestock. 28.4% had radios. 80.4% lacked any farm equipment. 7.6% owned an electric pump and 7% had an ox plough. A program could be offered after lunch and coordinated with other activities after 4 P.M. at a local center. The population would have to be oriented to business and income generation would have to be planned very carefully. PMID:12288810

  4. Petroleum maturation modelling, Abu Gabra Sharaf area, Muglad Basin, Sudan

    NASA Astrophysics Data System (ADS)

    Mohamed, Abdalla Y.; Pearson, Michael J.; Ashcroft, William A.; Whiteman, A. J.

    2002-08-01

    Structural and maturation studies in the northwest of the Muglad Basin, Sudan showed a thick sedimentary section up to 9000 m in the deep sub-basins and an average of about 6000 m in the Sharaf-Abu Gabra Ridge. The isopach map of the Lower Cretaceous Abu Gabra-Sharaf formations, which contain source rocks, showed a thickness of sedimentary section between 2000 and 5000 m. The burial history showed high subsidence rates during the first rifting phase with relatively low subsidence rates during the following two phases in this part of the basin. Significant erosion of the sedimentary section occurred in the ridge area during Miocene and Cenomanian-Albian times. The geothermal gradients in the modelled wells range between 18 and 27.5 °C/km corresponding to the relatively wide range of present day heat flow of between 37 and 63 mW/m 2, averaging 50 mW/m 2. Heat flow history curves consistent with vitrinite reflectance data were adopted with elevated high heat flow (75 mW/m 2) during the first rifting phase followed by minor peaks (average 60 mW/m 2) during the second and the third rifting phases. Application of a kinetic vitrinite maturation model resulted in a present day oil window between 2000 and 4500 m. The source rock of the Abu Gabra (AG) and Sharaf (SH) formations, which has an average total organic carbon of 1.0% and hydrogen index (HI) of 280, was modelled for hydrocarbon generation. The section was divided into four layers; AG-1 (Albian), AG-2 (Aptian), SH-1 (Barremian) and SH-2 (Neocomian). Conditions for hydrocarbon generation are present throughout the Sharaf formation and in AG-2. The generation model suggests an average generation amount of 4 mgHC/g rock in the lower three modelled layers with a timing range between 120 Ma and the present. Total calculated oil volume is about 370 US billion bbls and the expected volume expelled and migrated (40%) is 150 US billion bbls. The total gas expelled and migrated (90%) is 1600 US trillion cu ft. Retention of hydrocarbons may be adversely affected by long-continued faulting and lack of good seals.

  5. Magnetic Prospection at the Archaeological Site of Jebel Barkal, Sudan

    NASA Astrophysics Data System (ADS)

    Ali, Mohamed A. Mohamed; Goldmann, Thomas; Wolf, Pawel; Wützler, Ronny; Goldmann, Lukas; Hobbs, Richard; Kendall, Timothy

    2010-05-01

    One of most important archaeological sites in northern Sudan is Jebel Barkal, an isolated sandstone butte, which became the chief cult center of the ancient Sudanese kingdom of Kush (ca. 800 BC-400 AD). Located on the western edge of the modern town of Karima, just downstream from the Nile's fourth cataract, Jebel Barkal is the site of numerous ruined palaces, temples, and pyramids. In 2006 and 2007, we carried out a magnetic survey of about 3.5 hectares of the temple area using an Overhauser magnetometer GSM 19. Our objective was to prospect some of the unexcavated areas of the site to try to image the sub-soil remains, and our resulting map clearly shows a number of magnetic anomalies of mud-brick, fired brick and stone-block walls belonging to different ancient buildings. Our initial magnetic results successfully revealed one corner of the wall of the early Meroitic palace B 100, which had been "lost" after its excavation in 1916, since it buried by later excavation debris before it had been precisely located on any site map. Prospection in the same area also revealed other (earlier?) massive mud walls of unknown function and character. A second area we chose for examination was that in front of the Great Amun Temple (B 500). Here we found two or three small rectangular anomalies that suggested a series of small chapels built at right angles to the paved way leading into the Great Temple; the layout was identical to chapels in front of the Great Amun Temple at Meroe. Another magnetic anomaly in front of B 500 seemed to be a predictable type of stepped podium, well-known from other Kushite temples. A third area we chose to examine was that northeast of B 500. Here we found the clear outline of a multi-chambered building (B 1700) parallel to the Great Temple, which appeared to have all the characteristics of a smaller temple fronted by a pylon. Far less clear were the complex magnetic anomalies we found northeast of B 1700. These appeared to belong to a series of adjacent or overlapping structures, but why their plans were so incoherent was puzzling. All the features revealed by the magnetic survey are partially excavated and will be fully exposed within the next five years, this should shortly offer us the opportunity to correlate our magnetic images with actuality.

  6. Late Jurassic sodium-rich adakitic intrusive rocks in the southern Qiangtang terrane, central Tibet, and their implications for the Bangong-Nujiang Ocean subduction

    NASA Astrophysics Data System (ADS)

    Li, Yalin; He, Juan; Han, Zhongpeng; Wang, Chengshan; Ma, Pengfei; Zhou, Aorigele; Liu, Sheng-Ao; Xu, Ming

    2016-02-01

    The lack of magmatic records with high-quality geochronological and geochemical data in the central segment of the southern Qiangtang subterrane in central Tibet inhibits a complete understanding of the subduction polarity of the Bangong-Nujiang Ocean lithosphere during the Mesozoic. In this study, we present the zircon U-Pb age as well as geochemical and Sr-Nd-Pb isotopic data for the Late Jurassic pluton from the Kangqiong area in the central segment of the southern Qiangtang subterrane. The Kangqiong pluton primarily consists of granodiorites (SiO2 = 62.87-65.17 wt.%) and was emplaced in the Late Jurassic (147.6 ± 2.4-149.9 ± 2.1 Ma). The granodiorites display high Na2O numbers (Na2O/K2O = 1.75-2.24) as well as high MgO (2.21-3.14 wt.%) and Mg-numbers (53-58), are characterized by a low abundance of heavy rare earth elements (e.g., Yb = 1.05-1.92 ppm) and Y (12.63-17.52 ppm), and high Sr/Y (29-61) and La/Yb (14-18) ratios, which are comparable in composition to those of slab-derived adakitic rocks. The Kangqiong adakitic granodiorites have initial (87Sr/86Sr)i ratios of 0.70611 to 0.70669, negative εNd(t) values (- 1.06 to - 0.25), (206Pb/204Pb)t ratios of 18.42 to 18.47, (207Pb/204Pb)t ratios of 15.62 to 15.63, and (208Pb/204Pb)t ratios of 38.50 to 38.60. These geochemical signatures indicate that the magmas were most likely derived from the partial melting of the subducted Bangong-Nujiang oceanic crust and minor contaminants from the accretionary complex. Our results, in combination with the coeval magmatism in the western segment of the southern Qiangtang subterrane, indicate that the Bangong-Nujiang oceanic lithosphere was subducted northward beneath the Qiangtang Terrane, forming a west-east magmatic arc over 800 km during the Late Jurassic.

  7. Evidence for large-magnitude paleo-earthquakes on the Ventura fault: Implications for earthquake recurrence, fault slip rate, and seismic hazard assessment in southern California

    NASA Astrophysics Data System (ADS)

    Mcauliffe, L. J.; Dolan, J. F.; Hubbard, J.; Shaw, J. H.; Pratt, T. L.; Rhodes, E. J.

    2013-12-01

    New borehole, high-resolution seismic reflection, and geochronologic data reveal the ages and displacements of the two most recent large-magnitude earthquakes on the Ventura fault, the central segment of a large, multi-fault reverse fault system that extends for >200 km along the southern edge of the central and western Transverse Ranges fault system. Based on geomorphology and analysis of high-resolution seismic data acquired in 2010, we drilled 17 hollow stem auger boreholes and cone penetrometer tests along two transects across the locus of most recent folding above the Ventura fault. At Day Road in downtown Ventura, our 23-m-deep boreholes revealed a well-bedded alluvial section with many units that are traceable continuously along the entire 375 m length of the transect. Stratigraphic relationships indicate that the prominent topographic scarp at this site records ~6 m of uplift during fold growth in the most-recent earthquake on the underlying Ventura blind thrust ramp. Similarly, sedimentary growth observed in the borehole cross section indicates ~4.5 m of growth during the penultimate event, with an event horizon located at the base of a growth interval between 4 and 8.5 m depth south of the scarp. Six 14C and 14 OSL ages collected from the four hollow-stem auger boreholes at this site constrain the timing of the two most recent events on the Ventura blind thrust fault to post-2900 B.P. and 4700 × 350 to 5460 × 330 years before present; dating of additional shallow luminescence samples should help narrow the age range of the MRE. The large amounts of uplift in the two folding events indicate that they formed in response to large-displacement, and therefore large-magnitude earthquakes, likely involving rupture of the Ventura fault together with thrust ramps to both the west (e.g., Pitas Point fault) and east (Southern San Cayetano and eastern San Cayetano faults). These thrust faults form the middle section of a >200-km-long, east-west belt of large, interconnected reverse faults that extends along the southern edge of the Transverse Ranges. Although each of these faults represents a major seismic source in its own right, we are exploring the possibility of even larger-magnitude, multi-segment ruptures that may link these faults to other major faults to the east and west. The proximity of this large reverse-fault system to several major population centers, including the metropolitan Los Angeles region, and the potential for tsunami generation during offshore ruptures of the western parts of the system, emphasize the importance of understanding the behavior of these faults for seismic hazard assessment.

  8. Petrogenesis of the early Cretaceous intermediate and felsic intrusions at the southern margin of the North China Craton: Implications for crust-mantle interaction

    NASA Astrophysics Data System (ADS)

    Gao, Xin-Yu; Zhao, Tai-Ping; Bao, Zhi-Wei; Yang, Alexandra Yang

    2014-10-01

    New major and trace element, whole rock Sr and Nd isotopes and zircon U-Pb ages and Hf isotope data are presented for rocks from the early Cretaceous Tianqiaogou dioritic and Taishanmiao granitic plutons at the southern margin of the North China Craton (NCC), in order to investigate their petrogenesis and geological evolution. LA-ICP-MS U-Pb analyses for zircons from these two plutons yield similar 206Pb/238U ages of 122 Ma and 115-125 Ma, respectively. Monzodiorites from the Tianqiaogou pluton have whole rock εNd(t) values ranging from -6.2 to - 1.3 and zircon εHf(t) values from + 2.9 to + 6.2. They are variably enriched in Ra, Ba, and Sr, and depleted in Nb, Ta, Zr, Hf and Ti, indicating that they were derived from a depleted mantle and underwent subsequent magma differentiation and crustal contamination. The Taishanmiao pluton is composed of metaluminous to peraluminous highly fractionated I-type granites that have high SiO2, Na2O, K2O, Rb, Th, and U, and low P, Ba, Sr, Ti and Eu contents. The granites have strong negative whole rock εNd(t) values (- 16.1 to - 7.5) and zircon εHf(t) values (- 20.9 to - 6.1). Their Nd TDM ages (1.19 to 2.01 Ga) and zircon Hf TC DM ages (1565 to 2490 Ma) are much younger than the basement rocks beneath the southern margin of the NCC, suggesting derivation from an ancient crustal source with minor involvement of mantle-derived components. Therefore, rocks from the Tianqiaogou dioritic pluton were partial melts of the mantle source. Underplating of the mafic magmas initiated partial melting of the ancient continental crust, resulting in the formation of the Taishanmiao granitic pluton. Their complex petrogenesis reflects a strong crust-mantle interaction process related to lithospheric thinning beneath the southern margin of the NCC in early Cretaceous.

  9. Inclination shallowing in Eocene Linzizong sedimentary rocks from Southern Tibet: correction, possible causes and implications for reconstructing the India-Asia collision

    NASA Astrophysics Data System (ADS)

    Huang, Wentao; Dupont-Nivet, Guillaume; Lippert, Peter C.; van Hinsbergen, Douwe J. J.; Hallot, Erwan

    2013-09-01

    A systematic bias towards low palaeomagnetic inclination recorded in clastic sediments, that is, inclination shallowing, has been recognized and studied for decades. Identification, understanding and correction of this inclination shallowing are critical for palaeogeographic reconstructions, particularly those used in climate models and to date collisional events in convergent orogenic systems, such as those surrounding the Neotethys. Here we report palaeomagnetic inclinations from the sedimentary Eocene upper Linzizong Group of Southern Tibet that are ˜20° lower than conformable underlying volcanic units. At face value, the palaeomagnetic results from these sedimentary rocks suggest the southern margin of Asia was located ˜10°N, which is inconsistent with recent reviews of the palaeolatitude of Southern Tibet. We apply two different correction methods to estimate the magnitude of inclination shallowing independently from the volcanics. The mean inclination is corrected from 20.5° to 40.0° within 95 per cent confidence limits between 33.1° and 49.5° by the elongation/inclination (E/I) correction method; an anisotropy-based inclination correction method steepens the mean inclination to 41.3 ± 3.3° after a curve fitting- determined particle anisotropy of 1.39 is applied. These corrected inclinations are statistically indistinguishable from the well-determined 40.3 ± 4.5º mean inclination of the underlying volcanic rocks that provides an independent check on the validity of these correction methods. Our results show that inclination shallowing in sedimentary rocks can be corrected. Careful inspection of stratigraphic variations of rock magnetic properties and remanence anisotropy suggests shallowing was caused mainly by a combination of syn- and post-depositional processes such as particle imbrication and sedimentary compaction that vary in importance throughout the section. Palaeolatitudes calculated from palaeomagnetic directions from Eocene sedimentary rocks of the upper Linzizong Group that have corrected for inclination shallowing are consistent with palaeolatitude history of the Lhasa terrane, and suggest that the India-Asia collision began at ˜20°N by 45-55 Ma.

  10. Cytochrome P450 isozyme protein verified in the skin of southern hemisphere humpback whales (Megaptera novaeangliae): implications for biochemical biomarker assessment.

    PubMed

    Waugh, Courtney A; Huston, Wilhelmina M; Noad, Michael J; Bengtson Nash, Susan

    2011-04-01

    Large mysticete whales represent a unique challenge for chemical risk assessment. Few epidemiological investigations are possible due to the low incidence of adult stranding events. Similarly their often extreme life-history adaptations of prolonged migration and fasting challenge exposure assumptions. Molecular biomarkers offer the potential to complement information yielded through tissue chemical analysis, as well as providing evidence of a molecular response to chemical exposure. In this study we confirm the presence of cytochrome P450 reductase (CPR) and cytochrome P450 isoenzyme 1A1 (CYP1A1) in epidermal tissue of southern hemisphere humpback whales (Megaptera novaeangliae). The detection of CYP1A1 in the integument of the humpback whale affords the opportunity for further quantitative non-destructive investigations of enzyme activity as a function of chemical stress. PMID:21276991

  11. A New Estimate for Total Offset on the Southern San Andreas Fault: Implications for Cumulative Plate Boundary Shear in the Northern Gulf of California

    NASA Astrophysics Data System (ADS)

    Darin, M. H.; Dorsey, R. J.

    2012-12-01

    Development of a consistent and balanced tectonic reconstruction for the late Cenozoic San Andreas fault (SAF) in southern California has been hindered for decades by incompatible estimates of total dextral offset based on different geologic cross-fault markers. The older estimate of 240-270 km is based on offset fluvial conglomerates of the middle Miocene Mint Canyon and Caliente Formations west of the SAF from their presumed source area in the northern Chocolate Mountains NE of the SAF (Ehlig et al., 1975; Ehlert, 2003). The second widely cited offset marker is a distinctive Triassic megaporphyritic monzogranite that has been offset 160 ± 10 km between Liebre Mountain west of the SAF and the San Bernadino Mountains (Matti and Morton, 1993). In this analysis we use existing paleocurrent data and late Miocene clockwise rotation in the eastern Transverse Ranges (ETR) to re-assess the orientation of the piercing line used in the 240 km-correlation, and present a palinspastic reconstruction that satisfies all existing geologic constraints. Our reconstruction of the Mint Canyon piercing line reduces the original estimate of 240-270 km to 195 ± 15 km of cumulative right-lateral slip on the southern SAF (sensu stricto), which is consistent with other published estimates of 185 ± 20 km based on correlative basement terranes in the Salton Trough region. Our estimate of ~195 km is consistent with the lower estimate of ~160 km on the Mojave segment because transform-parallel extension along the southwestern boundary of the ETR during transrotation produces ~25-40 km of displacement that does not affect offset markers of the Liebre/San Bernadino correlation located northwest of the ETR rotating domain. Reconciliation of these disparate estimates places an important new constraint on the total plate boundary shear that is likely accommodated in the adjacent northern Gulf of California. Global plate circuit models require ~650 km of cumulative Pacific-North America (PAC-NAM) relative plate motion since ~12 Ma (Atwater and Stock, 1998). We propose that the continental component of PAC-NAM shear is accommodated by: (1) 195 ± 15 km on the southern SAF (this study); (2) 12 ± 2 km on the Whittier-Elsinore fault; (3) 75 ± 20 km of cumulative shear across the central Mojave in the eastern California shear zone; (4) 30 ± 4 km of post-13 Ma slip on the Stateline fault; and (5) 47 ± 18 km of NW-directed translation produced by north-south shortening. Together, these components sum to 359 ± 31 km of net dextral displacement on the SAF system (sensu lato) in southern California since ca. 12 Ma, or ~300 km less than what is required by the global plate circuit. This suggests that the continental component of post-12 Ma PAC-NAM transform motion can be no more than ~390 km in the adjacent northern Gulf of California, substantially less than the 450 km of shear proposed in some models. We suggest that the remaining ~270-300 km of NW-directed relative plate motion is accommodated by a small component of late Miocene extension and roughly 225 km of slip on the offshore borderland fault system west of Baja California.

  12. Southern Ocean air-sea heat flux, SST spatial anomalies, and implications for multi-decadal upper ocean heat content trends.

    NASA Astrophysics Data System (ADS)

    Tamsitt, V. M.; Talley, L. D.; Mazloff, M. R.

    2014-12-01

    The Southern Ocean displays a zonal dipole (wavenumber one) pattern in sea surface temperature (SST), with a cool zonal anomaly in the Atlantic and Indian sectors and a warm zonal anomaly in the Pacific sector, associated with the large northward excursion of the Malvinas and southeastward flow of the Antarctic Circumpolar Current (ACC). To the north of the cool Indian sector is the warm, narrow Agulhas Return Current (ARC). Air-sea heat flux is largely the inverse of this SST pattern, with ocean heat gain in the Atlantic/Indian, cooling in the southeastward-flowing ARC, and cooling in the Pacific, based on adjusted fluxes from the Southern Ocean State Estimate (SOSE), a ⅙° eddy permitting model constrained to all available in situ data. This heat flux pattern is dominated by turbulent heat loss from the ocean (latent and sensible), proportional to perturbations in the difference between SST and surface air temperature, which are maintained by ocean advection. Locally in the Indian sector, intense heat loss along the ARC is contrasted by ocean heat gain of 0.11 PW south of the ARC. The IPCC AR5 50 year depth-averaged 0-700 m temperature trend shows surprising similarities in its spatial pattern, with upper ocean warming in the ARC contrasted by cooling to the south. Using diagnosed heat budget terms from the most recent (June 2014) 6-year run of the SOSE we find that surface cooling in the ARC is balanced by heating from south-eastward advection by the current whereas heat gain in the ACC is balanced by cooling due to northward Ekman transport driven by strong westerly winds. These results suggest that spatial patterns in multi-decadal upper ocean temperature trends depend on regional variations in upper ocean dynamics.

  13. Structure of Tendaho Graben and Manda Hararo Rift: Implications for the evolution of the southern Red Sea propagator in Central Afar

    NASA Astrophysics Data System (ADS)

    Acocella, V.; Abebe, B.; Korme, T.; Barberi, F.

    2008-08-01

    The Red Sea and Aden rifts (or propagators) meet in Afar. Here we use remote sensing and field analyses to define the geology and structure of the southern part of the Red Sea propagator in Central Afar. This consists of the NW-SE trending Tendaho Graben (TG) and the younger and active NW-SE trending Manda Hararo Rift (MHR), partly within TG. Tectonic and volcanic activity within TG developed mostly between ˜1.8 and ˜0.6 Ma, with a stretching factor β ˜ 1.1, an extension rate ˜3.6 mm/yr and the fissural eruption of part (˜7000 km3/Ma) of the Afar Stratoid sequence (mainly basaltic lava flows and ignimbrites). MHR, before terminating southward, has a β ˜ 1.04 and an extension rate ˜1.2 mm/yr, and is associated with the emission of ˜600 km3/Ma of basalts in the last ˜0.2 Ma. These data suggest that after the exceptional amount of magma erupted between ˜1.8 and ˜0.6 Ma, magmatic and tectonic activity significantly decreased along the southern part of the Red Sea propagator in the last ˜0.2 Ma. This decrease coincides with the on-land development and migration of the more active (inferred extension rate in the order of ˜10 mm/yr, as proposed in previous studies) Aden propagator, suggesting that spreading in Central Afar mainly occurred along one active propagator at any one time.

  14. New [sup 40]Ar/[sup 39]Ar mica ages from eastern New Hampshire and southern Maine: Implications for the exhumation history of the region

    SciTech Connect

    Lux, D.R.; West, D.P. Jr. . Dept. of Geological Science)

    1993-03-01

    It has long been recognized that micas from the high-grade metamorphic terrane of Maine and New Hampshire have anomalously young K-Ar ages. Furthermore, ages show systematic spatial patterns. Samples from western New Hampshire are youngest and become progressively older towards the east. In the Kearsarge-Central Maine Synclinorium (KCMS) of western Maine, ages are oldest along the northern terminus of high grade metamorphism and become progressively younger towards the southwest. In order to understand this peculiar relationship, micas from 20 sites in eastern New Hampshire and southern Maine were dated by the [sup 40]Ar/[sup 39]Ar method. The following relationships are observed: (1) Micas from the KCMS of southern New Hampshire have Permo-Carboniferous ages and coexisting micas are highly discordant, (2) micas from within or very near the Massabesic Gneiss Complex have young ages ([approximately]240--250 Ma) and show little to no discordance, (3) with one exception, micas from south of the Sebago batholith in Maine are also young ([approximately]240--250 Ma) and show little to no discordance. North of the Sebago batholith the transition to older micas is gradual. Mica ages from the Massabesic Gneiss Complex are younger than in surrounding regions and the transition to older ages roughly coincides with the Campbell Hill and Flint Hill faults. Outside the zone of young micas, cooling curves are concave upward for the same temperature interval. The young micas are concordant indicating rapid cooling but they are [approximately]40 Ma younger than the time of Late Paleozoic metamorphism. Therefore the young ages cannot be explained by rapid post-metamorphic cooling. The authors believe the accelerated cooling is the result of regional tectonic exhumation related to the earliest stages of rifting associated with opening of the Atlantic.

  15. Petrogenesis of the early Cretaceous Funiushan granites on the southern margin of the North China Craton: Implications for the Mesozoic geological evolution

    NASA Astrophysics Data System (ADS)

    Gao, Xin-Yu; Zhao, Tai-Ping; Chen, Wei-Terry

    2014-11-01

    Late Mesozoic granitoids are ubiquitous in the southern margin of the North China Craton and are keys to the understanding of the Mesozoic geological evolution. The early Cretaceous Funiushan granitic pluton in the southern margin of the North China Craton is composed of porphyritic biotite monzogranites. Rocks from the Funiushan pluton have high SiO2 (64.45-73.98 wt.%), Na2O (3.19-4.67 wt.%) and K2O (3.76-7.95 wt.%) and low MgO (0.11-1.34 wt.%). They are enriched in Rb, Ba, Th, U and LREE ((La/Yb)N = 9.63-45.0), and depleted in Nb, Ta, Ti and P, and have negative Eu anomalies (Eu/Eu* = 0.29-0.72). This geochemical feature is similar to those of typical I-type granites. Zircons from the granites were dated using LA-ICP-MS and SIMS, and yielded 206Pb/238U ages of 115-131 Ma. They have εHf(t) values mainly vary from -17.7 to +0.9 and TDMC ages mainly from 2301 to 1118 Ma. Whole rock εNd(t) values range from -20.3 to -9.6 and TDM ages from 1.49 to 2.29 Ga, indicating that the magma was produced by partial melting of the Neoarchean to Paleoproterozoic crustal rocks, as represented by the Taihua Group basement rocks, with minor involvement of mantle-derived melts. The Funiushan pluton is considered to have been formed through a strong crust-mantle interaction process under a low pressure condition in an extensional setting, due to the lithospheric thinning caused by westward subduction of the Paleo-Pacific oceanic crust.

  16. Nd- and Sr-isotopic compositions of lavas from the northern Mariana and southern Volcano arcs: implications for the origin of island arc melts

    NASA Astrophysics Data System (ADS)

    Lin, P. N.; Stern, R. J.; Morris, J.; Bloomer, S. H.

    1990-09-01

    Nd- and Sr-isotopic data are reported for lavas from 23 submarine and 3 subaerial volcanoes in the northern Mariana and southern Volcano arcs. Values of ɛNd range from +2.4 to +9.5 whereas 87Sr/86Sr ranges from 0.70319 to 0.70392; these vary systematically between and sometimes within arc segments. The Nd-and Sr-isotopic compositions fall in the field of ocean island basalt (OIB) and extend along the mantle array. Lavas from the Volcano arc, Mariana Central Island Province and the southern part of the Northern Seamount Province have ɛNd to +10 and 87Sr/86Sr=0.7032 to 0.7039. These are often slightly displaced toward higher 87Sr/86Sr at similar ɛNd. In contrast, those lavas from the northern part of the Mariana Northern Seamount Province as far north as Iwo Jima show OIB isotopic characteristics, with ɛNd and 87Sr/86Sr=0.7035 to 0.7039. Plots of 87Sr/86Sr and ɛNd versus Ba/La and (La/Yb)n support a model in which melts from the Mariana and Volcano arcs are derived by mixing of OIB-type mantle (or melts therefrom) and a metasomatized MORB-type mantle (or melts therefrom). An alternate interpretation is that anomalous trends on the plots of Nd- and Sr-isotopic composition versus incompatible-element ratios, found in some S-NSP lavas, suggest that the addition of a sedimentary component may be locally superimposed on the two-component mixing of mantle end-members.

  17. Impact of moisture flux convergence and soil moisture on precipitation: a case study for the southern United States with implications for the globe

    NASA Astrophysics Data System (ADS)

    Wei, Jiangfeng; Su, Hua; Yang, Zong-Liang

    2016-01-01

    Interactions between soil moisture, evapotranspiration (ET), atmospheric moisture fluxes and precipitation are complex. It is difficult to attribute the variations of one variable to another. In this study, we investigate the influence of atmospheric moisture fluxes and land surface soil moisture on local precipitation, with a focus on the southern United States (U.S.), a region with a strong humidity gradient and intense moisture fluxes. Experiments with the Weather Research and Forecasting model show that the variation of moisture flux convergence (MFC) is more important than that of soil moisture for precipitation variation over the southern U.S. Further analyses decompose the precipitation change into several contributing factors and show that MFC affects precipitation both directly through changing moisture inflow (wet areas) and indirectly by changing the precipitation efficiency (transitional zones). Soil moisture affects precipitation mainly by changing the precipitation efficiency, and secondly through direct surface ET contribution. The greatest soil moisture effects are over transitional zones. MFC is more important for the probability of heavier rainfall; soil moisture has much weaker impact on rainfall probability and its roles are similar for the probability of intermediate-to-heavy rainfall (>10 mm day-1). Although MFC is more important than soil moisture for precipitation over most regions, the impact of soil moisture could be large over certain transitional regions. At the submonthly time scale, the African Sahel appears to be the only major region where soil moisture has a greater impact than MFC on precipitation. This study provides guidance to understanding and further investigation of the roles of local land surface processes and large-scale circulations on precipitation.

  18. Geology of the Eel River basin and adjacent region: Implications for late Cenozoic tectonics of the southern Cascadia subduction zone and Mendocino triple junction

    SciTech Connect

    Clarke, S.H. Jr. )

    1992-02-01

    Two upper Cenozoic depositional sequences of principally marine strata about 4,000 m thick overlie accreted basement terranes of the Central and Coastal belts of the Franciscan Complex in the onshore-offshore Eel River basin of northwestern California. The older depositional sequence is early to middle Miocene in age and represents slope basin and slope-blanket deposition, whereas the younger sequence, later Miocene to middle Pleistocene in age, consists largely of forearc basin deposits. Youthful tectonic activity related to Gorda-North American plate convergence indicates an active Cascadia subduction zone and strong partial coupling between these plates. Structures of the northeastern margin of the Eel River basin are principally north-northwest-trending, east-northeast-dipping thrust and reverse faults that form imbricate thrust fans. The Coastal belt fault, the early Tertiary accretionary suture between the Franciscan Central and Coastal belts, can be traced from Arcata Bay northward offshore to the southern Oregon border. It is tentatively extended farther northward based on aeromagnetic data to an offshore position west of Cape Blanco. Thereafter, it may coincide with the offshore Fulmar fault. The Cascadia subduction zone (CSZ) does not join the Mendocino transform fault at the commonly depicted offshore location of the Mendocino triple junction (MTJ). Instead, the CSZ extends southeastward around the southern Eel River basin and shoreward along Mendocino Canyon to join the Petrolia shear zone. Similarly, the Mendocino fault may extend shoreward via Mattole Canyon and join the Cooskie shear zone. These two shear zones intersect onshore north of the King Range, and the area of their intersection is the probable location of the MTJ.

  19. The upper lithostratigraphic unit of ANDRILL AND-2A core (Southern McMurdo Sound, Antarctica): local Pleistocene volcanic sources, paleoenvironmental implications and subsidence in the southern Victoria Land Basin

    NASA Astrophysics Data System (ADS)

    Del Carlo, P.; Panter, K. S.; Bassett, K. N.; Bracciali, L.; di Vincenzo, G.; Rocchi, S.

    2009-12-01

    We report results from the study of the uppermost 37 meters of the Southern McMurdo Sound (SMS) AND-2A drillcore, corresponding to the lithostratigraphic unit 1 (LSU 1), the most volcanogenic unit within the core. Nearly all of LSU 1 consists of volcanic breccia and sandstone that is a mixture of near primary volcanic material dominated by lava and vitric clasts with minor exotic material derived from distal basement sources. Lava clasts and glass are mafic and range from strongly alkaline (basanite, tephrite) to moderately alkaline (alkali basalt, hawaiite) compositions that are similar to nearby land deposits. 40Ar-39Ar laser step-heating analyses on groundmass separated from lava clasts yield Pleistocene ages (692±38 and 793±63, ±2σ internal errors). Volcanoes of the Dailey Island group, located ~13 km SW of the drillsite, are a possible source for the volcanic materials based on their close proximity, similar composition and age. A basanite lava flow on Juergens Island yields a comparable Pleistocene age of 775±22 ka. Yet there is evidence to suggest that the volcanic source is much closer to the drillsite and that the sediments were deposited in much shallower water relative to the present-day water depth of 384 mbsl. Evidence for local volcanic activity is based in part on the common occurrence of delicate vitriclasts (e.g. glass shards and Pele’s hair) and a minimally reworked ~2 meter thick monomict breccia that is interpreted to have formed by autobrecciating lava. In addition, conical-shaped seamounts and high frequency magnetic anomalies encompass the drillsite and extend south including the volcanoes of the Dailey Islands. Sedimentary features and structures indicate shallow water sedimentation for the whole of LSU 1. Rippled asymmetric cross-laminated sands and hummocky cross-stratification occur intermittently throughout LSU 1 and indicate water depths shallower than 100 meters. The occurrence of ooliths and layers containing siderite and Fe-rich cement, along with the occurrence of shallow water diatoms, all indicate deposition in shallow waters agitated by waves. These results contrast strikingly with the present water depth, and let us infer rapid recent tectonic subsidence within this segment of the Victoria Land Basin (Terror Rift).

  20. Influence of climate and land use in carbon biogeochemistry in lower reaches of rivers in central southern Chile: Implications for the carbonate system in river-influenced rocky shore environments

    NASA Astrophysics Data System (ADS)

    Pérez, Claudia A.; DeGrandpre, Michael D.; Lagos, Nelson A.; Saldías, Gonzalo S.; Cascales, Emma-Karin; Vargas, Cristian A.

    2015-04-01

    Freshwater discharge affects the biogeochemistry of river-influenced nearshore environments by contributing with carbon and nutrients. An increase in human activities in river basins may alter the natural riverine nutrients and carbon export to coastal ecosystems. Along a wide latitudinal range (32°55'S-40°10'S), this study explores the role of climate and land use in determining the nutrient and carbon concentrations in the river mouth and fluxes to adjacent coastal areas. Between winter 2011 and fall 2012, we collected monthly samples in five river mouths in central southern Chile and at rocky shore sites affected by river plumes. Basins were characterized by different land uses and meteorological conditions along this latitudinal range. Water samples were collected for pH measurements, nutrients, dissolved organic and inorganic carbon, particulate organic carbon, and isotopic signatures (δ13C). Our results show a north-south gradient in concentrations of nutrients and carbon. The highest concentrations were observed in the Maipo basin, which presents the highest percentage of urban-industrial activities. Nutrients and carbon contributions, in most cases, were lowest in the southern Valdivia basin, which has the least human intervention and a greater percentage of vegetation. The Biobío River had the highest nutrient and carbon fluxes, in most cases, due to its high river discharge. Our results show the influence of river plume effects on carbon and nitrogen concentrations in river-influenced rocky shore sites. Moreover, our study suggests that land use might influence some parameters of carbonate system in rivers and river-influenced rocky shore environments. River-influenced rocky shore environments may exhibit suppression in aragonite saturation state with implications for calcifiers inhabiting these marine environments.

  1. Representation of drought frequency in Southern South America performed by 14 CMIP5 models. Drought risk implications and perspectives towards future projections

    NASA Astrophysics Data System (ADS)

    Rivera, J. A.; Penalba, O. C.

    2012-12-01

    Drought frequency estimation is a key variable for drought risk assessment. The aim of this research is to evaluate how well the global climate models (GCMs) represent the drought frequencies in Southern South America (south of 20°S). For that purpose, we used the Standardized Precipitation Index (SPI), which quantifies the number of standard deviations that the accumulated rainfall in a given time scale deviates from the average value of a location in a particular period. The SPI is one of the drought indices most widely used worldwide, and one of the best suited for the study area. In order to build this index, monthly rainfall data were obtained from the CLARIS LPB Data Base for 120 of its stations, which were subjected to quality control procedures and have less than 10% of missing values. The SPI was computed for the period 1979-2008 on a time scale of 12 months, which represents long-term droughts. This procedure was also applied to the simulated precipitation from 14 CMIP5 GCMs over the study area. Two types of comparisons were performed, the first one for drought frequencies without taking into account the different drought classes and the second one for the frequencies of moderate, severe and extreme drought events. This second comparison is important given that drought risk was evaluated through a weighted index based in drought frequencies, which was constructed as a sum of drought classes -moderate, severe and extreme- with a weighting scheme. Most of the regions with moderate to high observed drought frequencies are located in the western and southern portions of La Plata Basin and over Patagonia region, while lower observed drought frequencies were obtained for Northern Argentina, Southern Brazil and Paraguay. This spatial pattern is barely reproduced by the modeled frequencies, and in some cases major differences exist. In order to analyze these differences, we performed a regional assessment of the SPI time series, which showed that the time series of the model outputs are inconsistent with the variabilities based on observed precipitation data. This also indicates that monthly and seasonal variabilities of precipitation are misrepresented by the models and this result contributes to the poor representation of the drought frequency patterns. These are the kind of variabilities that could be important for the forecasting of droughts on seasonal scales and could help to a seasonal risk assessment, which is important for the agricultural and hydrological sectors. Moreover, the spatial pattern of annual precipitation are poorly reproduced, with a subestimation of precipitation over La Plata Basin and an overestimation over Patagonia, leeward the Andes. These results prove that GCMs outputs are far to be used for drought risk assessment in the region, given the substantial differences in the frequency patterns. Also, future projections must be evaluated carefully in longer time scale resolutions.

  2. Comprehensive Waveform Cross-correlation of Southern California Seismograms: Part 1. Refined Hypocenters Obtained Using the Double-difference Method and Tectonic Implications

    NASA Astrophysics Data System (ADS)

    Hauksson, E.; Chi, W.; Shearer, P.

    2003-12-01

    We present preliminary results applying waveform cross-correlation to southern California seismograms for over 380,000 events between 1984 and 2002. Waveforms recorded by the SCSN are first extracted from the SCEDC data center in 50 s windows that include both P and S waves. The resulting online waveform archive uses about 0.5 TB on a RAID system. The traces are then re-sampled to a uniform 100 Hz sample rate and band-pass filtered to between 1 and 10 Hz. Next, we apply time domain waveform cross-correlation for P and S waves between each event and 100 neighboring events (identified from the catalog based on a 3-D velocity model of Hauksson (2000). We identify and save differential times from the peaks in the cross-correlation functions and use a spline interpolation method to achieve a nominal timing precision of 0.001 s. These differential times, together with existing P and S phase picks, are input to the double-difference program of Waldhauser and Ellsworth (2000). We define a grid across southern California and locate hypocenters near each grid node. Because some events may be located many times as hypocenters are calculated near successive grid-points, we assign a weight to each hypocenter and calculate a weighted average hypo-center for each earthquake. The new HypoDD hypocenters show improved clustering both horizontally and vertically, creating a more focused picture of the previously identified, spatially complex distributions of seismicity. In many cases, the late Quaternary faults, such as the Elsinore and Hollywood-Santa Monica faults appear to bracket the seismicity distributions; in other cases, the faults trace the median within a symmetric distribution of hypocenters. The depth distribution of the seismicity shows sudden changes across some of the major strike-slip faults, while regions of dip-slip faulting are often bound by dipping surfaces that are clearly defined by the deepest hypocenters. The seismicity around the southern San Andreas fault shows clear alignment along the Carrizo Plain segment while both the Mojave and Coachella Valley segments are dominated by off-fault hypocenters. A prominent horizontal boundary striking a few degrees north of west with a prominent depth change in the seismicity cuts across Banning Pass towards San Bernardino. Earthquake swarms in the Salton Sea at the south end of the San Andreas fault suggest the presence of two north-northwest striking seismic zones at the south end of the San Andreas fault. The seismicity along the San Jacinto fault forms sharp alignments that in most cases are adjacent to, but not coincident with, the mapped surface traces that are either parallel to the traces or form high angles to them. In the Los Angeles basin, the major aftershock sequences appear as densely focused clusters within a cloud of scattered background seismicity. The seismicity along the Newport-Inglewood fault forms a sharp alignment to the north and a diffuse distribution to the south, where the 1933 Long Beach earthquake occurred. Similarly, several clusters as well as scattered background seismicity extending from east to west across the basin illuminate the blind thrusts beneath the north edge of the basin. The major aftershock sequences such as 1992 Landers, 1994 Northridge, and 1999 Hector Mine form clusters, with distinct internal structures, illuminating secondary faults and a heterogeneous main fault rupture surface. Some of these alignments suggest that high angle cross-faults were activated by the mainshock.

  3. A lithofacies terrain model for the Blantyre Region: Implications for the interpretation of palaeosavanna depositional systems and for environmental geology and economic geology in southern Malawi

    NASA Astrophysics Data System (ADS)

    Dill, H. G.; Ludwig, R.-R.; Kathewera, A.; Mwenelupembe, J.

    2005-06-01

    The Blantyre City Area is part of the African savanna in southern Malawi. Sedimentological, geomorphological, chemical and mineralogical studies were conducted to create a lithofacies terrain model. The project involves mapping, cross-sectioning, grain size, heavy mineral analysis, XRD and the study of sedimentary textures under the petrographic microscope. These classical techniques were combined with GIS-based field and office works. The combined efforts led to 2-D maps and 3-D block diagrams that illustrate the geomorphological and sedimentological evolution of the landscape in southern Malawi during the late Mesozoic and Cenozoic. The results obtained through integrated geomorphological-sedimentological studies form the basis for land management (planning of residential areas, waste disposal sites, assessment of bearing capacity of rocks), geohazard prediction (delineation of high risk zones in terms of mass flow and inundation) and the evaluation of high-place (ceramic raw materials) and high-unit value (placers of precious metals and gemstones) mineral commodities in the study area. The study addresses regional and general aspects alike. In regional terms, the study aimed at unraveling the evolution of landforms at the southern end of the East African Rift System during the most recent parts of the geological past. Four stages of peneplanation were established in the working area. Planation was active from the Cretaceous to the Quaternary (stage I: early to mid-Cretaceous, stage II: early Tertiary, stage III: early to mid-Tertiary, stage IV: mid- to late Tertiary). During the most recent parts of the Quaternary, strong fluvial incision was triggered by the base-level lowering of the Shire River. Geomorphological alteration of the landscape goes along with a phyllosilicate-sesquioxide transformation from minerals indicative of more acidic meteoric fluids (e.g., gibbsite, kaolinite) to those typical of more alkaline conditions (e.g. smectite, vermiculite, hydrobiotite). In addition, the investigation is to provide some characteristic features suitable for the recognition and interpretation of terrestrial environments resembling the present-day savanna in the ancient sedimentary record: Conspicuous bimodality in the grain-size distribution. High degree of gravel roundness. Boulder fields (basal conglomerates) with fitting breccias and no rotation of structural elements. Poor to very poor sorting of siliciclastics. Stratification is rare; if present only in sandy beds with antidune and tabular cross-bedding at low angle prevailing over cross-bedding at high angle. Grading rare; in arenaceous deposits poorly developed FU sequences, in rudites poorly developed CU sequences, locally with surface armoring. Directional sedimentary structures in coarse-grained deposits are unimodal. Fabric types: a(t)b(i) and a(p)b(i); shear planes indicative of slide may be present. Ribbon-shaped architectural elements prevail over channel-like types. Bounding surfaces/unconformities are uneven to wavy and more widespread than scour-and-pool structures. Fine-grained carbonaceous interbeds are restricted to shallow depressions. Etch marks such as tafonis, flutes, honeycomb textures are common. Placer deposits of metallic and non-metallic mineral commodities are abundant. Alucretes and ferricretes of bog iron (ferrihydrite > goethite) and lateritic (goethite > ferrihydrite) types are common, calcitic freshwater limestones and gypcretes are scarce. Kandite-group minerals "in" (relic), smectite-group minerals "in", vermiculite "in" (recent), mica-group minerals "out".

  4. Meso-Cenozoic tectonics of the southern Patagonian foreland: Structural evolution and implications for Au-Ag veins in the eastern Deseado Region (Santa Cruz, Argentina)

    NASA Astrophysics Data System (ADS)

    Giacosa, R.; Zubia, M.; Sánchez, M.; Allard, J.

    2010-12-01

    Located in the centre of the Argentinean Patagonia between 46° and 49°S, the Deseado Region represents the foreland domain of the Southern Patagonian Andes. Its geology is characterized by thick Mesozoic sequences which, at its eastern sector, present a Mesozoic and Cenozoic geologic evolution which has been strongly determined by the development of three major tectonic phases. The present research is based on field geological mapping, interpretation of seismic and aeromagnetic data, as well as satellite image analysis. This approach has allowed us to identify and characterize the deformation that occurred throughout Jurassic, Cretaceous and Miocene times. We interpret that the most relevant structural features are the result of normal faulting generated as a response to the Jurassic rifting stage. These extensional features have strongly influenced the subsequent geometry and distribution of younger Cretaceous and Cenozoic structures. The Jurassic extensional deformation, which affected major areas of Southern Gondwana, is the product of a major intra-continental rifting stage which was accompanied by synkinematic volcanism. This tectonic regime is characterized by SW-NE directed extension that generated major oblique WNW trending faults accommodating regional dextral-extension. In the study area, this tectonic regime is inferred from the geometries of major fault systems interpreted from available seismic reflection data, as well as from the spatial distribution and orientation of the extensional fracturing associated with the opening of hybrid and dilatational siliceous epithermal Au-Ag veins. Following the Jurassic rifting stage, a more restricted Cretaceous -post-Neocomian-compressional tectonic phase took place. Throughout this period, we interpret the previously formed Jurassic extensional structures to have been reactivated under sinistral transpression. Deformation during this period generated sinistral-reverse WNW belts of deformation, which accommodated reverse faulting, imbricate thrusts, dextral and sinistral R 1 and R 2 shears and disharmonic folds due to a buttress effect. Under the post-Oligocene Andean regime, W-E directed compression acted on previously-formed N to NNE-oriented normal faults. Compression and shortening uplifted a series of narrow and sub-meridional ranges which run as a 200 km long inversion-related tectonic front along the Patagonian foreland. Between 47°11' and 48°40'S, one of these NNE ranges divides the entire Deseado Region into two distinctive structural domains. Whilst the western domain presents dominant NNW morphotectonic features, that to the east appears highly dominated by WNW fabrics of Jurassic and Cretaceous age. The structural features of the Eastern domain appear to extend further north of the Deseado Region towards the vicinity of the San Jorge Gulf. This WNW-trending belt hosts pre-Upper Cretaceous rocks and pre-drift basement rocks which include igneous Paleozoic metamorphic rocks and Permian to Triassic sedimentary units. The Deseado region's epithermal Au-Ag Jurassic vein systems result from the infilling and deposition of low temperature hydrothermal fluids within dilatational and hybrid structures. These spectacular vein systems are compatible with the regional SW-NE extension direction controlled by the Jurassic intra-continental rifting of southern Gondwana. Dilatational and hybrid veins are preferentially hosted by fractures in the Jurassic volcanic rocks, while the veins located within the pre-volcanic basement preferentially infill normal faults. Finally, most of these epithermal vein fields where exhumed during a moderate phase of inversion during Cretaceous times.

  5. Ground-water geology of Kordofan Province, Sudan

    USGS Publications Warehouse

    Rodis, Harry G.; Hassan, Abdulla; Wahadan, Lutfi

    1968-01-01

    For much of Kordofan Province, surface-water supplies collected and stored in hafirs, fulas, and tebeldi trees are almost completely appropriated for present needs, and water from wells must serve as the base for future economic and cultural development. This report describes the results of a reconnaissance hydrogeologic investigation of the Province and the nature and distribution of the ground-water resources with respect to their availability for development. Kordofan Province, in central Sudan, lies within the White Nile-Nile River drainage basin. The land surface is largely a plain of low relief; jebels (hills) occur sporadically, and sandy soils are common in most areas except in the south where clayey soils predominate. Seasonal rainfall, ranging from less than 100 millimeters in the north to about 800 millimeters in the south, occurs almost entirely during the summer months, but little runoff ever reaches the Nile or White Nile Rivers. The rocks beneath the surficial depsits (Pleistocene to Recent) in the Province comprise the basement complex (Precambrian), Nawa Series (upper Paleozoic), Nubian Series (Mesozoic), laterite (lower to middle Tertiary), and the Umm Ruwaba Series (Pliocene to Pleistocene). Perennial ground-water supplies in the Province are found chiefly in five hydrologic units, each having distinct geologic or hydrologic characteristics. These units occur in Nubian or Umm Ruwaba strata or both, and the sandstone and conglomerate beds form the :principal aquifers. The water is generally under slight artesian head, and the upper surface of the zone of saturation ranges from about 50 meters to 160 meters below land surface. The surficial deposits and basement rocks are generally poor sources of ground water in most of the Province. Supplies from such sources are commonly temporary and may dissipate entirely during the dry season. Locally, however, perennial supplies are obtained from the surficial deposits and from the basement rocks. Generally, water from Nubian aquifers is satisfactory for most uses and is of better quality than that obtained from Umm Ruwaba aquifers. The relatively high mineralization of water from the Umm Ruwaba, especially in the eastern part of the Province, makes the water unsuitable for many municipal ad industrial uses. The water is generally usable, however, for domestic and livestock purposes. Some 175 drilled wells located at 75 water yards yield an average, of about 1,000 imperial gallons .per hour per well from Nubian or Umm Ruwaba. aquifers. Generally the water yards provide sufficient water for minimum domestic and livestock requirements throughout the year. Commonly, however, the water yards are widely separated and, hence, not always properly spaced for good range management or for serving the needs of the dispersed rural population. In 1962, withdrawals from Nubian and Umm Ruwaba aquifers in the Province were approximately 600 million gallons annually. This rate of draft: could probably be continued almost indefinitely without significant depletion of the water supply. Nubian and Umm Ruwaba aquifers in the southwestern part of Kordofan offer excellent potential for future development. Nubian aquifers in northern Kordofan need extensive exploration by test drilling before their economic potential can be properly evaluated.

  6. Mapping Precambrian structures in the Sahara Desert with SIR-C/X-SAR radar: The Neoproterozoic Keraf Suture, NE Sudan

    NASA Astrophysics Data System (ADS)

    Abdelsalam, Mohamed G.; Stern, Robert J.

    1996-10-01

    A major N-trending Neoproterozoic suture between composite arc terranes of the Arabian-Nubian Shield in the east and older crust of the Nile Craton to the west is inferred to trend N-S close to the Nile in northern Sudan. We used shuttle imaging radar (SIR) C/X synthetic aperture radar (SAR) imagery to find and map these structures in the poorly known Keraf Suture which are not apparent on visible or near IR imagery due to extensive sand cover. L band (23 cm wavelength) radar images best resolve geologic structure; the other frequencies of the SIR-C/X-SAR system (X and C bands) permit qualitative evaluation of the effects of surface versus subsurface backscattering. Interpretation of L band images supported by field work indicates that the Keraf Suture is ~50 km wide and >550 km long, making it the longest basement structure recognized to date in NE Africa. The northern part of the Suture comprises ophiolitic rocks which were thrust westward over tightly folded sediments of the Nile Craton. The southern Keraf Suture is dominated by N- and NNW-trending, left-lateral strike-slip faults that affect previously deformed passive margin sediments. Associated with these faults are NE-trending transpressional folds and a possible transtensional basin. These structures are interpreted to be due to NW-SE oblique collision between the Arabian-Nubian Shield and the Nile Craton, as east and west Gondwana collided in the last 150 m.y. of Neoproterozoic time.

  7. Provenance Ages of Protoliths From the Chiapas Massif Complex and Adjacent Strata of the Southern Maya Block - Implications on the Paleozoic Reconstruction of Middle America.

    NASA Astrophysics Data System (ADS)

    Weber, B.; Schaaf, P.; Valencia, V. A.; Lopez-Martinez, M.; Ortega-Gutierrez, F.

    2007-05-01

    The basement of the Maya block is exposed in the Maya Mountains of Belize, the Chuacús Complex of Guatemala, and in the Chiapas Massif Complex (CMC) of SE Mexico. In the CMC medium- to high-grade metasedimentary rocks occur as isolated domains in mostly metaigneous crystalline rocks. The most important tectonothermal event in the entire CMC is of late Permian age, culminating in partial anatexis and the intrusion of the Chiapas batholith. In this work we present U-Pb data obtained by LA-MC-ICPMS from detrital zircon cores of metasediments from the CMC and from detrital zircons of Paleozoic strata exposed in SE Chiapas. The Pennsylvanian-Permian Santa Rosa Formation (SRF) contains mostly Pan-African (500-650 Ma) zircons, minor populations of Silurian-Early Devonian (400-420 Ma) and Grenville (1.0-1.25 Ga) zircons, and few Paleoproterozoic and Archean grains. The maximum sedimentation age is documented by ~320 Ma old zircons. Metagreywacke and metasandstones of the central CMC have inherited detrital zircon cores with age distributions indistinguishable from those of the SRF. High-grade metapelites and para-amphibolites from the CMC, instead, have inherited zircon cores with one single population of 1.0 Ga or with populations at 1.0, 1.2, and 1.5 Ga. In the southern part of the CMC leucocratic granites intrude sedimentary rocks whose detrital zircons yielded mostly 1.53 Ga ages with some grains in the range of 1.6-1.7 Ga, but no younger zircons. White mica grown in contact with the leucogranite has a 40Ar- 39Ar age of 406 ± 4 Ma, defining a minimum age for both deposition of the sediments and intrusion of the leucogranite. Our data indicate that the CMC has a composite pre-metamorphic basement, containing sedimentary protoliths from the Pennsylvanian-Permian SRF and from early Paleozoic strata intruded by Silurian-Early Devonian granites. This favors a similar pre-Permian geologic history for the CMC as for the Maya Mountains of Belize. The early Paleozoic sediments were shed from a Mesoproterozoic landmass with ages typically observed from the SW Amazon craton; however, it seems more likely that during the Silurian-Early Devonian the Maya block was situated close to the southern Grenville Province of Laurentia where ancestors from the SW Amazon craton, but no Pan-African belts, are present. By initiating the collision between Gondwana and Laurentia during the Carboniferous, the sediments were shed mostly from the newly formed orogens close to West Africa, which contains mainly Pan-African crust.

  8. High-Precision U-Pb Zircon Geochronology of Southern African Cratonic Mantle Eclogites and Implications for Subcontinental Lithospheric Mantle Evolution and Metasomatism

    NASA Astrophysics Data System (ADS)

    Schmitz, M. D.; Bowring, S. A.

    2002-05-01

    Zircon is a trace constituent of a number of Group II eclogites from the Group 2 Lace kimberlite (133+/-3 Ma, central craton) and the Group 1 Lovedale kimberlite (74+/-1 Ma, southwestern craton margin) of the Kaapvaal craton of southern Africa. High-precision ID-TIMS U-Pb isotopic measurements of single zircon grains has revealed numerous episodes of zircon growth which provide insight into the timing of eclogite genesis and subsequent metasomatism of the subcontinental lithospheric mantle. Single zircons from eclogites in both kimberlites yield near-concordant Late Archean (2.78 to 2.63 Ga) dates, providing a minimum age for eclogite formation; similarities with the timing of intracratonic mafic volcanism suggest a link between magmatic intraplating and Group II eclogite formation. These Late Archean zircons also unequivocally establish the closed-system behavior of zircon with respect to Pb diffusion in these lithospheric mantle samples, and confirm the nature of recorded isotopic dates as crystal growth ages. In one of the Lovedale eclogites, Late Archean zircon is accompanied by a much more abundant and morphologically distinct phase of zircon, of which single grains define a mixing array between 0.95 and 0.16 Ga. These data are interpreted to represent intracrystalline mixtures of zircon of these two growth ages, which themselves may date episodes of thermally- or fluid-induced mantle metasomatism. The former age coincides with the latest stages of Mesoproterozoic Kaapvaal-Namaqualand convergent margin orogenesis, while the latter overlaps in time with proximal Group 2 kimberlite emplacement during southern Gondwana breakup. Eclogites from the Lace kimberlite also contain younger zircons, with an enigmatic range of near concordant dates at ca. 0.80 to 0.20 Ga. The latter is the sole constituent in one eclogite nodule, and is precisely dated at 205.7+/-0.4 Ma by three concordant zircons. This age significantly predates nearly all Group 1 and Group 2 kimberlite emplacement, as well as the rapid extrusion of the Karoo volcanics at 180 Ma; only the Dokolwayo kimberlite of Swaziland, in the extreme eastern craton may be of comparable age. We suggest that this Jurassic eclogitic zircon growth in the lithosphere beneath the central Kaapvaal craton preserves a unique record of heating and/or the infiltration of metasomatizing agents into the subcontinental mantle during the earliest stages of supercontinent breakup.

  9. Early evolution of the southern margin of the Neuquén Basin, Argentina: Tectono-stratigraphic implications for rift evolution and exploration of hydrocarbon plays

    NASA Astrophysics Data System (ADS)

    D'Elia, Leandro; Bilmes, Andrés; Franzese, Juan R.; Veiga, Gonzalo D.; Hernández, Mariano; Muravchik, Martín

    2015-12-01

    Long-lived rift basins are characterized by a complex structural and tectonic evolution. They present significant lateral and vertical stratigraphic variations that determine diverse basin-patterns at different timing, scale and location. These issues cause difficulties to establish facies models, correlations and stratal stacking patterns of the fault-related stratigraphy, specially when exploration of hydrocarbon plays proceeds on the subsurface of a basin. The present case study corresponds to the rift-successions of the Neuquén Basin. This basin formed in response to continental extension that took place at the western margin of Gondwana during the Late Triassic-Early Jurassic. A tectono-stratigraphic analysis of the initial successions of the southern part of the Neuquén Basin was carried out. Three syn-rift sequences were determined. These syn-rift sequences were located in different extensional depocentres during the rifting phases. The specific periods of rifting show distinctly different structural and stratigraphic styles: from non-volcanic to volcanic successions and/or from continental to marine sedimentation. The results were compared with surface and subsurface interpretations performed for other depocentres of the basin, devising an integrated rifting scheme for the whole basin. The more accepted tectono-stratigraphic scheme that assumes the deposits of the first marine transgression (Cuyo Cycle) as indicative of the onset of a post-rift phase is reconsidered. In the southern part of the basin, the marine deposits (lower Cuyo Cycle) were integrated into the syn-rift phase, implying the existence of different tectonic signatures for Cuyo Cycle along the basin. The rift climax becomes younger from north to south along the basin. The post-rift initiation followed the diachronic ending of the main syn-rift phase throughout the Neuquén Basin. Thus, initiation of the post-rift stage started in the north and proceeded towards the south, constituting a diachronous post-rift event. This arrangement implies that the lower part of Cuyo Cycle, traditionally related to regional thermal subsidence, may be deposited during either mechanical subsidence or thermal subsidence according to its position within the basin.

  10. Pervasive Palaeogene remagnetization of the central Taurides fold-and-thrust belt (southern Turkey) and implications for rotations in the Isparta Angle

    NASA Astrophysics Data System (ADS)

    Meijers, Maud J. M.; van Hinsbergen, Douwe J. J.; Dekkers, Mark J.; Altıner, Demir; Kaymakcı, Nuretdin; Langereis, Cor G.

    2011-03-01

    The Turkish Anatolide-Tauride block rifted away from the northern margin of Gondwana in the Triassic, which gave way to the opening of the southern Neo-Tethys. By the late Palaeocene to Eocene, it collided with the southern Eurasian margin, leading to the closure of the northern Neo-Tethys ocean. To determine the position of the Anatolide-Tauride block with respect to the African and Eurasian margin we carried out a palaeomagnetic study in the central Taurides belt, which constitutes the eastern limb of the Isparta Angle. The sampled sections comprise Carboniferous to Palaeocene rocks (mainly limestones). Our data suggest that all sampled rocks are remagnetized during the late Palaeocene to Eocene phase of folding and thrusting event, related to the collision of the Anatolide-Tauride block with Eurasia. To further test the possibility of remagnetization, we use a novel end-member modelling approach on 174 acquired isothermal remanent magnetization (IRM) curves. We argue that the preferred three end-member model confirms the proposed remagnetization of the rocks. Comparing our data to the post-Eocene declination pattern in the central Tauride belt, we conclude that our clockwise rotations are in agreement with data from other studies. After combining our results with previously published data from the Isparta Angle (that includes our study area), we have reasons to cast doubt on the spatial and temporal extent of an earlier reported early to middle Miocene remagnetization event. We argue that the earlier reported remagnetized directions from Triassic rocks—in tilt corrected coordinates—from the southwestern Antalya Nappes (western Taurides), are in good agreement with other studies from the area that show a primary origin of their characteristic remanent magnetization. This implies that we document a clockwise rotation for the southwestern Antalya Nappes since the Triassic that is remarkably similar to the post-Eocene (˜40°) rotation of the central Taurides. For the previously published results that are clearly remagnetized, we argue that their remagnetization has occurred in the Palaeocene to Eocene.

  11. Tectonic geomorphology and paleoseismology of strike-slip faults in Jamaica: Implications for distribution of strain and seismic hazard along the southern edge of the Gonave microplate

    NASA Astrophysics Data System (ADS)

    Koehler, R. D.; Mann, P.; Brown, L. A.

    2009-12-01

    The east-west, left lateral strike-slip fault system forming the southern edge of the Gonave microplate crosses the110-km-long and 70-km-wide island of Jamaica. GPS measurements in the northeastern Caribbean are supportive of the microplate interpretation and indicate that ~ half of the Caribbean-North America left-lateral plate motion (8-14 mm/yr) is carried by the Plantain Garden (PGFZ) and associated faults in Jamaica. We performed Neotectonic mapping of the Plantain Garden fault along the southern rangefront of the Blue Mountains and conducted a paleoseismic study of the fault at Morant River. Between Holland Bay and Morant River, the fault is characterized by a steep, faceted, linear mountain front, prominent linear valleys and depressions, shutter ridges, and springs. At the eastern end of the island, the PGFZ is characterized by a left-stepping fault geometry that includes a major, active hot spring. The river cut exposure at Morant River exposes a 1.5-m-wide, sub-vertical fault zone juxtaposing sheared alluvium and faulted Cretaceous basement rocks. This section is overlain by an, unfaulted 3-m-thick fluvial terrace inset into a late Pleistocene terrace that is culturally modified. Upward fault terminations indicate the occurrence of three paleoearthquakes that occurred prior to deposition of the flat lying inset terrace around 341-628 cal yr BP. At this time, our radiocarbon results suggest that we can rule out the PGFZ as the source of the 1907 Kingston earthquake 102 years ago, as well as, the 1692 event that destroyed Port Royal 317 years ago and produced a major landslide at Yallahs. Pending OSL ages will constrain the age of the penultimate and most recent ruptures. Gently to steeply dipping rocks as young as Pliocene exposed in roadcuts within the low coastal hills south of and parallel to the Plantain Garden fault may indicate active folding and blind thrust faulting. These structures are poorly characterized and may accommodate an unknown amount of oblique strain. Reconnaissance mapping was also performed along the South Coast fault in south-central Jamaica north of Portland Ridge, and along the Crawle River-Rio Minho fault near Frankfield in the Central Inlier. The absence of fault scarps or other tectonic geomorphic features across fluvial terraces of the Milk and Minho Rivers indicate that the South Coast fault has not been active in Holocene time. Left laterally offset streams, linear valleys, and saddles support active faulting along the east-west Crawle River-Rio Minho fault that is roughly collinear with the western extension of the Plantain Garden fault.

  12. Elemental and Sr Nd isotopic systematics of the early Mesozoic volcanic sequence in southern Jiangxi Province, South China: petrogenesis and tectonic implications

    NASA Astrophysics Data System (ADS)

    Wang, Yuejun; Fan, Weiming; Peng, Touping; Guo, Feng

    2005-02-01

    Elemental and Sr Nd isotopic results are presented for the early Mesozoic volcanic sequence (~172 Ma) in southern Jiangxi Province, South China. The sequence is voluminously composed of ~45% subalkaline basaltic rocks (group 1), <5% high-mg andesite dacites (group 2) and ~50% rhyolites (group 3). The group 1 rocks are characterized by (La/Yb)cn = 3.8 7.2, Eu/Eu* = 0.65 1.15, Nb/La = 0.64 0.99, 87Sr/86Sr(t) = 0.70602~0.70822 and ɛNd(t) = -1.63 to +0.11, similar to those of an EMII-like source. The group 2 rocks have mg=0.42~0.60, SiO2=60.24~66.71%, MgO=2.65~ 5.54%, Ni=24~102 ppm and Cr=84~266 ppm, classified as high-mg andesitic rocks. These rocks are more enriched in LILEs and LREE with more significant negative Eu anomaly (0.63~0.79), are more depleted in HFSEs with Nb/La ratios of 0.40 0.56 and have lower ɛNd(t) (-9.44 to -7.78) and higher 87Sr/86Sr(t) (0.70985~0.71016), in comparison with the group 1 rocks. They most likely originated from metasomatised veins in the lithospheric mantle. The origination of the group 1 and group 2 magma suggests the development of a peridotite-plus-vein lithospheric mantle during early Mesozoic era beneath the interior of the Cathaysian block. The group 3 rhyolites are characterized by high SiO2 (72.75~77.97%), Zr (99~290 ppm), Hf (3.9~9.7 ppm) and Ga/Al (2.76~3.87) and significant Nb Ta, Ba Sr and P Ti depletions. These rhyolites exhibit Sr Nd isotopic compositions (87Sr/86Sr(t) = 0.70962~0.71104, ɛNd(t) = -4.63 to -5.80) similar to the contemporaneous Zhaibei and Pitou A-type granites in the area. Such characteristics suggest that they might be derived from the underplating basaltic magma contaminated by crustal materials. Therefore, an early Mesozoic rifting model in response to intracontinental lithospheric extension is proposed to account for the early Mesozoic volcanism in southern Jiangxi Province, South China.

  13. Modeling the bloom evolution and carbon flows during SOIREE: Implications for future in situ iron-enrichments in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Hannon, E.; Boyd, P. W.; Silvoso, M.; Lancelot, C.

    The impact of a mesoscale in situ iron-enrichment experiment (SOIREE) on the planktonic ecosystem and biological pump in the Australasian-Pacific sector of the Southern Ocean was investigated through model simulations over a period of 60-d following an initial iron infusion. For this purpose we used a revised version of the biogeochemical SWAMCO model ( Lancelot et al., 2000), which describes the cycling of C, N, P, Si, Fe through aggregated chemical and biological components of the planktonic ecosystem in the high nitrate low chlorophyll (HNLC) waters of the Southern Ocean. Model runs were conducted for both the iron-fertilized waters and the surrounding HNLC waters, using in situ meteorological forcing. Validation was performed by comparing model predictions with observations recorded during the 13-d site occupation of SOIREE. Considerable agreement was found for the magnitude and temporal trends in most chemical and biological variables (the microbial food web excepted). Comparison of simulations run for 13- and 60-d showed that the effects of iron fertilization on the biota were incomplete over the 13-d monitoring of the SOIREE bloom. The model results indicate that after the vessel departed the SOIREE site there were further iron-mediated increases in properties such as phytoplankton biomass, production, export production, and uptake of atmospheric CO 2, which peaked 20-30 days after the initial iron infusion. Based on model simulations, the increase in net carbon production at the scale of the fertilized patch (assuming an area of 150 km2) was estimated to 9725 t C by day 60. Much of this production accumulated in the upper ocean, so that the predicted downward export of particulate organic carbon (POC) only represented 22% of the accumulated C in the upper ocean. Further model runs that implemented improved parameterization of diatom sedimentation (i.e. including iron-mediated diatom sinking rate, diatom chain-forming and aggregation) suggested that the downward POC flux predicted by the standard run might have been underestimated by a factor of up to 3. Finally, a sensitivity analysis of the biological response to iron-enrichment at locales with different initial oceanographic conditions (such as mixed-layer depth) or using different iron fertilization strategies (single vs. pulsed additions) was conducted. The outcomes of this analysis offer insights in the design and location of future in situ iron-enrichments.

  14. Geochronology and geochemistry of late Paleozoic magmatic rocks in the Yinwaxia area, Beishan: Implications for rift magmatism in the southern Central Asian Orogenic Belt

    NASA Astrophysics Data System (ADS)

    Zheng, Rongguo; Wu, Tairan; Zhang, Wen; Meng, Qingpeng; Zhang, Zhaoyu

    2014-09-01

    Mafic-ultramafic rocks are distributed widely in the Beishan rift, which is located in the southern Beishan, central southern Central Asian Orogenic Belt. The Yinwaxia study area is located in eastern Beishan rift, where mafic-ultramafic rocks occur along major faults. The zircon SHRIMP U-Pb age obtained of a gabbro is 281 ± 11 Ma, and the age of the basalt is constrained by the youngest xenocrystal with an age of 265 Ma, which substantiate that these mafic rocks formed in Permian. Basalts and gabbros exhibit similar geochemical characteristics including: high SiO2, total Fe2O3 and TiO2 contents; low MgO contents and Mg# values; and tholeiitic characteristics. Yinwaxia mafic rocks have relatively high total rare earth element contents, enrichment in light rare earth elements, enrichments in the high field strength elements, and obvious negative Nb-Ta-Ti anomalies. Basalts exhibit low (87Sr/86Sr)i and high εNd(t) values, while gabbros exhibit relatively high (87Sr/86Sr)i and low εNd(t) values. Isotopic compositions of these mafic rocks display a mixed trend between depleted and enriched mantles. Meanwhile, differing εNd(t) values show that basalts were intensively contaminated by juvenile crustal materials, but gabbros were contaminated by older continental crust. We conclude that Yinwaxia mafic rocks were derived from lithospheric mantle metasomatized by fluids and/or melts from subducted slab; parental magmas underwent AFC processes, then emplaced along faults in a continental rift. We collected geochemical and geochronological data in the study area, and collated geochronological data from previous workers in the Beishan orogenic belt to develop a geochronological frequency diagram. From these data and analyses we deduced a model of tectonic evolution for the Beishan orogenic belt. Considering the geochemistry, sedimentological evidence for rifting, and the geochronological frequency diagram, we propose that the Beishan rift had entered a post-collision stage since Early Devonian, and then changed into a continental rift stage around late Carboniferous-early Permian.

  15. Northern versus southern gateways control on ocean overturning circulation at the Eocene-Oligocene transition and possible implications to global cooling

    NASA Astrophysics Data System (ADS)

    Abelson, M.; Erez, J.

    2013-12-01

    There is a growing body of evidence indicating reorganization in the ocean overturning circulation during the transition from the Eocene to the Oligocene, in particular, the initiation of the northern-sourced overturning circulation that comprises the northern component water (NCW) and northward flowing intermediate water. This evidence includes Nd isotopes from the Southern Hemisphere, δ13C from intermediate water in the subtropical North Atlantic, and increasing difference in the benthic δ18O between the Northern and Southern Hemispheres. We compare all these sets of proxies and show that the increasing trends have been conjugated throughout most of the Oligocene indicating enhancement of the northern-sourced overturning circulation that began around the Eocene-Oligocene transition (EOT). This reorganization was attributed mainly to the development of the wind-driven Antarctic circumpolar current (ACC). Based on variety of geological inferences, we suggest that the shift to interhemispheric bipolar overturning circulation was initiated by buoyancy fluxes formed by the development of anti-estuarine circulation between the Nordic Seas and the North Atlantic around the EOT, which significantly intensified the NCW. The Nordic anti-estuarine circulation began at a critical threshold during rapid tectonic subsidence of the Greenland-Scotland Ridge (GSR) triggered by the suppression of the Iceland mantle plume. We show that the development of northern-sourced circulation cell during the Oligocene correlates compellingly with the histories of the GSR subsidence and the activity of the Iceland mantle plume, and to a lesser degree with the ACC history. Accordingly, this circulation was enhanced as long as the GSR subsided rapidly. The onset of the northern-sourced overturning circulation, which is the biologically productive circulation domain, has probably triggered the marked increase in the ocean productivity during the EOT. The relationship between the EOT climatic changes (δ18O, CO2 proxies) and circulation proxies may suggest that growing rates of burial of organic carbon caused by the productivity increase could have triggered an accelerated decrease in atmospheric CO2, which in turn caused the cooling at the first stage of the EOT.

  16. Surface exposure chronology of the Waimakariri glacial sequence in the Southern Alps of New Zealand: Implications for MIS-2 ice extent and LGM glacial mass balance

    NASA Astrophysics Data System (ADS)

    Rother, Henrik; Shulmeister, James; Fink, David; Alexander, David; Bell, David

    2015-11-01

    During the late Quaternary, the Southern Alps of New Zealand experienced multiple episodes of glaciation with large piedmont glaciers reaching the coastal plains in the west and expanding into the eastern alpine forelands. Here, we present a new 10Be exposure age chronology for a moraine sequence in the Waimakariri Valley (N-Canterbury), which has long been used as a reference record for correlating glacial events across New Zealand and the wider Southern Hemisphere. Our data indicate that the Waimakariri glacier reached its maximum last glaciation extent prior to ∼26 ka well before the global last glaciation maximum (LGM). This was followed by a gradual reduction in ice volume and the abandonment of the innermost LGM moraines at about 17.5 ka. Significantly, we find that during its maximum extent, the Waimakariri glacier overflowed the Avoca Plateau, previously believed to represent a mid-Pleistocene glacial surface (i.e. MIS 8). At the same time, the glacier extended to a position downstream of the Waimakariri Gorge, some 15 km beyond the previously mapped LGM ice limit. We use a simple steady-state mass balance model to test the sensitivity of past glacial accumulation to various climatic parameters, and to evaluate possible climate scenarios capable of generating the ice volume required to reach the full local-LGM extent. Model outcomes indicate that under New Zealand's oceanic setting, a cooling of 5 °C, assuming modern precipitation levels, or a cooling of 6.5 °C, assuming a one third reduction in precipitation, would suffice to drive the Waimakariri glacier to the eastern alpine forelands (Canterbury Plains). Our findings demonstrate that the scale of LGM glaciation in the Waimakariri Valley and adjacent major catchments, both in terms of ice volume and downvalley ice extent, has been significantly underestimated. Our observation that high-lying glacial surfaces, so far believed to represent much older glacial episodes, were glaciated during the LGM, challenges the conventional geomorphic model of glaciation in New Zealand where the vertical arrangement of glacial landform-associations is used to assign successively older glaciation ages.

  17. Southern Italy

    NASA Technical Reports Server (NTRS)

    1973-01-01

    This rare cloud free view of southern Italy (41.0N, 16.0E) shows almost all of the famous `boot' configuration of the peninsula up to just north of Naples and Mount Vesuvius. The land mass of this historic peninsula contrasts sharply with the sparkling blue waters of the Mediterranean Sea.

  18. The AyiaTriadha Cave, Southern Euboea Finds and Implications of the Earliest Human Habitation in the Area (A Preliminary Report).

    NASA Astrophysics Data System (ADS)

    Mavridis, F.; Tankosić, Ž.

    The Ayia Triadha cave excavation project aims to explore early maritime connections in the Aegean during the Late Neolithic I and II and the Early Bronze Age. The cave lies in a strategic position close to the crossroads that connect insular regions and the mainland. We also aim to explore the manifestations of the so-called Saliagos culture of the Cyclades and the Aegean. This culture is connected to the White-on-Dark pottery horizon (late sixth to early fifth millennium B.C.) found in the cave. The Final Neolithic/LNIIa material is also present in the cave in large quantities. It is closely connected to the Attica-Kephala horizon (late fifth/fourth millennium B.C.) known from the Cyclades and the southern part of mainland Greece. Of great importance is the identification of an Early Bronze Age context, located inside a small chamber, off the main entrance corridor. In this paper we present our preliminary results from the 2007 field season and some aspects of the 2008 campaign together with research strategies we plan to apply in the future.

  19. Migration of growth axial surfaces and its implications for multiphase tectono-sedimentary evolution of the Zhangwu fault depression, southern Songliao Basin, NE China

    NASA Astrophysics Data System (ADS)

    Gui, Baoling; He, Dengfa; Chen, Weijia; Zhang, Wenjun

    2014-04-01

    The normal fault-bend folding theory uses active axial surfaces, inactive axial surfaces, and growth axial surfaces to describe the geometric relationship between faults and deformation of a hanging wall. The dip of a growth axial surface is related to the fault slip rate and the basin sedimentation rate: higher fault slip rates result in smaller dips of growth axial surfaces, whereas higher basin sedimentation rates produce larger dips of growth axial surfaces. Moreover, the growth axial surface will be a straight line if both the fault slip and sedimentation rates remain relatively unchanged, but will become curved if both rates are variable. Therefore, the characteristics of growth axial surfaces can provide clear information on the evolution of faulting and deposition. By studying the seismic profiles of the Zhangwu fault depression of the southern Songliao Basin, we show that the migration of growth axial surfaces and unconformities can be used as indicators of basin development. Multiphase tectonic activity will not only produce unconformities but also result in migration of growth axial surfaces or inactive axial surfaces. Therefore, the normal fault-bend folding theory, particularly with regard to the evolution of growth axial surfaces, can be applied to the interpretation of geometric and kinematic evolutions of half-grabens and the exploration of related tectono-sedimentary processes.

  20. Contrasting styles of mineralization in the Chinese Altai and East Junggar, NW China: implications for the accretionary history of the southern Altaids

    NASA Astrophysics Data System (ADS)

    Wan, Bo; Xiao, Wenjiao; Windley, Brian

    2013-04-01

    The Chinese Altai-East Junggar collage in the southern Altaids hosts three metallogenic belts, which are, from north to south: (1) a volcanogenic massive sulphide (VMS) Cu-Pb-Zn belt; (2) a belt of shear zone-related gold deposits; (3) a porphyry Cu-Au-Mo belt. The VMS deposits formed in two pulses (c. 405 Ma and c. 375 Ma) in the Chinese Altai arc. The porphyry deposits developed in three pulses in the East Junggar arc, the first two synchronous with the VMS mineralization, and the third at c. 330 Ma. The shear zone-related gold deposits developed in the late Carboniferous to Permian at the contact between the Chinese Altai and East Junggar arcs. Time-space distributions of diverse ore deposits across the Altai-East Junggar collage indicate that the collage developed from two independent arcs, the Chinese Altai and the East Junggar. The VMS and porphyry deposits developed in the Chinese Altai and East Junggar arcs, respectively. The Chinese Altai arc is interpreted to be a Japanese-type arc, and the East Junggar arc a Mariana-type arc. During the latest Palaeozoic, the two arcs were juxtaposed by the Erqis Fault, when many shear zone-related lode gold deposits were emplaced. These metallogenic distributions were a likely response to spatially localized mechanisms of crust growth and to the tectonic evolution of the Altai-East Junggar collage, and they are consistent with interpretation of the Altaids as a multiple subduction-accretion collage.

  1. Low-grade metamorphism in the eastern Southern Alps: Distribution, conditions, timing and implications for the tectonics of the Alps and NW Dinarides

    NASA Astrophysics Data System (ADS)

    Neubauer, Franz; Heberer, Bianca; Genser, Johann; Friedl, Getrude

    2014-05-01

    Based on 40Ar/39Ar dating of newly-grown syntectonic metamorphic white mica (sericite), we recognize for the first time the timing of Alpine low-grade metamorphism in the eastern part of the Southalpine unit: (1) A Silurian phyllite of Seeberg inlier located to the south of the Periadriatic fault yields a plateau age at c. 75 Ma suggesting a Late Cretaceous age of previously recognized low-grade (Rantitsch & Rainer, 2003) metamorphism. (2) Within the Tolmin nappe, four sericite plateau ages of mainly Middle Triassic volcanics are at c. 51 Ma (Early Eocene). The Late Cretaceous age in the Seeberg inlier is considered to record ductile deformation during formation of a retro-wedge related to the Eo-Alpine orogeny in the Austroalpine units in the Eastern Alps exposed north of the future Periadriatic fault. The Eocene age at the boundary of very low-grade to low-grade metamorphism in the Tolmin nappe (Rainer et al., 2009) relates to the emplacement of the Southalpine nappe complex onto the Dinarides and is contemporaneous with the initial ductile deformation in the Dinarides during Adria-directed shortening and formation of a siliciclastic flysch belt in front of the SW-directed growing fold-thrust belt (Placer, 2008). Similar rare Late Cretaceous and dominant Eocene ages within post-Variscan units are virtually more widespread in the Southalpine unit and Dinarides as considered before. These regions include the Collio basin (Feijth, 2002) and the Eder unit (Läufer et al., 1996) in the western and central Southern Alps, in the internal NW Dinarides (Borojević Šoštarić et al., 2012) and the Mid Bosnian Schist Mountains (Pamić et al., 2004) and Lim Paleozoic unit in the central Dinarides (Ilic et al., submitted). Consequently, the Southalpine unit and Dinarides were affected by two stages of metamorphism, Late Cretaceous (ca. 80 to 75 Ma) and Eocene (ca. 51 - 40 Ma), both stages are related to back-thrusting. The ages of metamorphism are different from those in the main body of the Alpine orogen exposed north of the E-trending Periadriatic fault. In previous interpretations, the eastern Southalpine unit was considered to differ in many respects from Alpine units north of the Periadriatic fault including (1) no Alpine metamorphic overprint and, therefore, (2) also no Alpine ductile deformation in contrast to amphibolite- and even eclogite- grade metamorphism (ca. 100 - 85 Ma) in Austroalpine units north of the fault, and by (3) S- to SW-, Adria-directed vergency of the deformation of mostly Eocene to Neogene age in contrast to all units basically directed to the north and northwest, towards the stable European plate. The Southalpine unit is considered as back-thrust of the Middle-Late Eocene plate collision between Stable Europe and the Alpine thrust wedge (Doglioni & Bosellini, 1987). The new data from the eastern part of the Southalpine unit challenge this view and imply a steadily but slowly growing Adria-directed thrust wedge between Maastrichtian and Early Eocene times. Acknowledement: The work has been supported by the Austrian Science Fund (project no. 22,110). References Borojević Šoštarić, S. Neubauer, F., Handler, R., Palinkaš, L. A., 2012. Variscan vs. Alpine tectonothermal events in NW-Dinarides: constraints from 40Ar/39Ar dating. Geologica Carpathica, 63, 441-452. Doglioni, C., Bosellini, A., 1987. Eoalpine and mesoalpine tectonics in the Southern Alps. Geologische Rundschaus, 76, 735-754. Feijth, J., 2002. Paleozoic and Mesozoic tectonometamorphic development and geochronology of the Orobic chain (Southern Alps, Lombardy, Italy). PhD thesis, Faculty of Engineering and Applied Geosciences, Technical University of Berlin, 136 p. Ilić, A., Neubauer, F., Handler, R. (submitted). Formation of a structural dome due to transpression: The Lim unit in Central Dinarides. Journal of Structural Geology. Läufer, A.L., Frisch, W., Steinitz, G., Loeschke, J., 1997. Exhumed fault-bounded Alpine blocks along the Periadriatic lineament: the Eder unit (Carnic Alps, Austria). Geologische Rundschau, 86, 612-626. Pamić, J., Balogh, K., Hrvatović, H., Balen, D., Jurković, I., Palinkaš, L., 2004. K-Ar and Ar-Ar dating of the palaeozoic metamorphic complex from the Mid-Bosnian Schist Mts., central Dinarides, Bosnia and Hercegovina. Mineralogy and Petrology, 82, 65 Borojević Šoštarić 79. Placer, L., 2008. Principles of the tectonic subdivision of Slovenia. Geologija 51/2, 205-217. Rantitsch, G., Rainer, T., 2003. Thermal modeling of Carboniferous to Triassic sediments of the Karawanken Range (Southern Alps) as a tool for paleogeographic reconstructions in the Alpine-Dinaridic-Pannonian realm. International Journal of Earth Sciences, 92, 195-209. Rainer, T., Sachsenhofer, R. F., Rantitsch G., Herlec, U., Vrabec, M., 2009. Organic maturity trends across the Variscan discordance in the Alpine-Dinaric Transition Zone (Slovenia, Austria, Italy): Variscan versus Alpidic thermal overprint. Austrian Journal of Earth Sciences, 102, 120-133.

  2. Regional variations in upper mantle compressional velocities beneath southern California 1. Post-shock temperatures: Their experimental determination, calculation, and implications, 2.. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Raikes, S. A.

    1978-01-01

    The compressional velocity within the upper mantle beneath Southern California is investigated through observations of the dependence of teleseismic P-delays at all stations of the array on the distance and azimuth to the event. The variation of residuals with azimuth was found to be as large as 1.3 sec at a single station; the delays were stable as a function of time, and no evidence was found for temporal velocity variations related to seismic activity in the area. These delays were used in the construction of models for the upper mantle P-velocity structure to depths of 150 km, both by ray tracing and inversion techniques. The models exhibit considerable lateral heterogeneity including a region of low velocity beneath the Imperial Valley, and regions of increased velocity beneath the Sierra Nevada and much of the Transverse Ranges. The development is described of a technique for the experimental determination of post-shock temperatures, and its application to several metals and silicates shocked to pressures in the range 5 to 30 GPa. The technique utilizes an infra-red radiation detector to determine the brightness temperature of the free surface of the sample after the shock wave has passed through it.

  3. Abrupt turnover in calcareous-nannoplankton assemblages across the Paleocene/Eocene Thermal Maximum: implications for surface-water oligotrophy over the Kerguelen Plateau, Southern Indian Ocean

    USGS Publications Warehouse

    Jiang, Shijun; Wise, Sherwood W., Jr.

    2007-01-01

    Ocean Drilling Program (ODP) Core Section 183-1135A-25R-4 from the Kerguelen Plateau in the Indian Ocean sector of the Southern Ocean represents only the second complete, expanded sequence through the Paleocene/Eocene Thermal Maximum (PETM; ~55 Ma) recovered from Antarctic waters. Calcareous nannoplankton at this site underwent an abrupt, fundamental turnover across the PETM as defined by a carbon isotope excursion. Although Chiasmolithus, Discoaster, and Fasciculithus exponentially increase in abundance at the onset, the former abruptly drops but then rapidly recovers, whereas the latter two taxa show opposite trends due to surface-water oligotrophy. These observations confirm previous results from ODP Site 690 on Maud Rise. The elevated pCO2 that accompanied the PETM caused a shoaling of the lysocline and carbonate compensation depth, leading to intensive dissolution of susceptible holococcoliths and poor preservation of the assemblages. Similarities and contrasts between the results of this study and previous work from open-ocean sites and shelf margins further demonstrate that the response to the PETM was consistent in open-ocean environments, but could be localized on continental shelves where nutrient regimes depend on the local geologic setting and oceanographic conditions.

  4. Implications and concerns of deep-seated disposal of hydrocarbon exploration produced water using three-dimensional contaminant transport model in Bhit Area, Dadu District of Southern Pakistan.

    PubMed

    Ahmad, Zulfiqar; Akhter, Gulraiz; Ashraf, Arshad; Fryar, Alan

    2010-11-01

    A three-dimensional contaminant transport model has been developed to simulate and monitor the migration of disposal of hydrocarbon exploration produced water in Injection well at 2,100 m depth in the Upper Cretaceous Pab sandstone, Bhit area in Dadu district of Southern Pakistan. The regional stratigraphic and structural geological framework of the area, landform characteristics, meteorological parameters, and hydrogeological milieu have been used in the model to generate the initial simulation of steady-state flow condition in the underlying aquifer's layers. The geometry of the shallow and deep-seated characteristics of the geological formations was obtained from the drilling data, electrical resistivity sounding surveys, and geophysical well-logging information. The modeling process comprised of steady-state simulation and transient simulation of the prolific groundwater system of contamination transport after 1, 10, 30 years of injection. The contaminant transport was evaluated from the bottom of the injection well, and its short- and long-term effects were determined on aquifer system lying in varying hydrogeological and geological conditions. PMID:19936954

  5. Illite-smectite patterns in sheared Pleistocene mudstones of the Southern Apennines and their implications regarding the process of illitization: A multiscale analysis

    NASA Astrophysics Data System (ADS)

    Casciello, Emilio; Cosgrove, John W.; Cesarano, Massimo; Romero, Enrique; Queralt, Ignasi; Vergés, Jaume

    2011-11-01

    The transformation of water-rich smectite clay minerals into relatively anhydrous illite is a common reaction in sedimentary basins. It is commonly thought to be driven by temperature increase with increasing burial depth. This mineral transformation is also observed in the gouge of large faults, and because it releases bound water from smectite, it is thought to be a key control in hydrologic and mechanical processes at subduction complexes. In this work, the distribution of smectite and illite within a large fault zone of the Southern Apennines of Italy is analysed at scales varying from outcrop to sub millimetre. X-ray diffraction analyses indicate a direct link between the darkening in colour of the sheared mudstone and the illitization of smectite. The heterogeneous distribution of illite and smectite within this shear zone was studied by integrating outcrop-scale observations with a peeling technique that allows microscope and SEM observations to be made over areas in excess of 60 cm2. The observed patterns of smectite illitization suggest that temperature is not the primary cause of the mineral transformation inside the fault. The distribution of illite along planes of the P foliation and in the infill of shears indicates that shear stress facilitates the mineral transformation.

  6. Petrofacies and provenance of the Puente Formation (middle to upper Miocene), Los Angeles basin, southern California: Implications for rapid uplift and accumulation rates

    SciTech Connect

    Critelli, S.; Rumelhart, P.E.; Ingersoll, R.V.

    1995-10-02

    The Peunte Formation is a Middle-Upper Miocene clastic unit lying unconformably on the Lower-Middle Miocene El Modeno Volcanics and Topanga Group, in the Los Angeles basin. The Puente Formation, about 3900 m thick, is composed of conglomerate, sandstone, and mudrock deposit;ed as a submarine fan at bathyal depths. Several intrabasinal discordances suggest tectonic activity during deposition. The succession consists of two main upward-thickening and -coarsening megacycles, reflecting submarine-fan progradation. The Puente Formation is characterized up-section by: (1) thin-bedded sandstone and shale (La Vida member) grading to thick-bedded sandstone and conglomerate (Soquel Member); and (2) thin-bedded mudrock and sandstone (Yorba Member) grading to thick- to very thick-bedded sandstone and conglomerate (Sycamore Canyon Member). There is consistent provenance signal in spite of complex transportation tectonics, responsible for opening of the Los Angeles Basin, and later transpressional processes, which are still active. Detailed provenance study of the Puente Formation and related units provides important constraints on paleogeographic and paleotectonic reconstructions of southern California basins and uplifts.

  7. Isotopic composition of a calcite-cemented layer in the Lower Jurassic Bridport Sands, southern England: Implications for formation of laterally extensive calcite-cemented layers

    SciTech Connect

    Bjoerkum, P.A. ); Walderhaug, O. )

    1993-07-01

    [delta][sup 18]O[sub PDB] and [delta][sup 13]C[sub PDB] values have been measured on 107 calcite cement samples from a laterally extensive (> 3 km) and continuous calcite-cemented layer 0.5 m thick in the coastal exposures of the Lower Jurassic shallow-marine Bridport Sands in Dorset, southern England. The samples were taken from a two-dimensional grid with 10-cm horizontal and vertical spacing between samples and along individual vertical lines across the calcite-cemented layer, [delta][sup 18]O[sub PDB] values vary between [minus]4.8% and [minus]9.2% and decrease radially outwards from points with lateral spacings on the order of 0.5-1 m in the middle of the calcite-cemented layer. The [delta][sup 18]O[sub PDB] values therefore indicate that the calcite-cemented layer was formed by merging of concretions. All [delta][sup 13]C[sub PDB] values measured are in the narrow range [minus]2.2% to [minus]0.5%, which suggests that the dominant source of calcite cement in the layer was biogenic carbonate.

  8. Factors affecting competitive dominance of rainbow trout over brook trout in southern Appalachian streams: Implications of an individual-based model

    SciTech Connect

    Clark, M.E.; Rose, K.A.

    1997-01-01

    We used an individual-based model to examine possible explanations for the dominance of rainbow trout Oncorhynchus mykiss over brook trout Salvelinus fontinalis in southern Appalachian streams. Model simulations were used to quantify the effects on interspecific competition of (1) competitive advantage for feeding sites by rainbow trout, (2) latitudinal differences in stream temperatures, flows, and daylight, (3) year-class failures, (4) lower fecundity of brook trout, and (5) reductions in spawning habitat. The model tracks the daily spawning, growth, and survival of individuals of both species throughout their lifetime in a series of connected stream habitat units (pools, runs, or riffles). Average densities of each species based on 100-year simulations were compared for several levels of each of the five factors and for sympatric and allopatric conditions. Based on model results and empirical information, we conclude that more frequent year-class failures and the lower fecundity of brook trout are both possible and likely explanations for rainbow trout dominance, that warmer temperatures due to latitude and limited spawning habitat are possible but unlikely explanations, and that competitive advantage for feeding sites by rainbow trout is an unlikely explanation. Additional field work should focus on comparative studies of the reproductive success and the early life stage mortalities of brook and rainbow trout among Appalachian streams with varying rainbow trout dominance. 53 refs., 11 figs.

  9. The Sr and Nd isotopic variations of the southern Japan Sea sediments over the past 48 ka: Implications for terrigenous sediment provenance and East Asian Monsoon

    NASA Astrophysics Data System (ADS)

    Zou, Jianjun; Shi, XueFa; Zhu, Aimei

    2015-04-01

    143Nd/144Nd and 87Sr/86Sr ratios of the acid-insoluble residues of the fine-grained sediments (<63μm) of core KCES1 collected from the Ulleung Basin (southern Japan Sea) were investigated. The Sr isotopic compositions of the sediments range between 0.718-0.723 with an average value of 0.72. ɛNd values vary from -10.12 to -12.03 with an average vaule of -11.02. Temporal distributions of the Sr and Nd isotopes of the sediments showed higher Sr isotope ratios and lower Nd isotope ratios during the Holocene, increasing trends of Sr and Nd isotope ratios during the last deglaciation and relatively stable Sr and Nd isotope ratios during the last glacial periods. The downcore variations in Sr and Nd isotopic compositions indicate climatically induced changes in sediment provenance from two isotopically distinct end-members: Yangtze River and Chinese Loess Plateau. Sediments deposited after 8 ka were supplied mainly from the Yang River, while before 8 ka the eolian input contributed much to the sediments. The rapid change in sediment source is closely related to the evolution of East Asian Monsoon and sea level. Acknowledgements: This study was supported by the National Natural Science Foundation of China (Grant No. 41476056, 41206059) and by Basic Scientific Fund for National Public Research Institutes of China (No. 2012G31, GY0213G23).

  10. Geomorphic assessment of late Quaternary volcanism in the Yucca Mountain area, southern Nevada: Implications for the proposed high-level radioactive waste repository

    SciTech Connect

    Wells, S.G.; McFadden, L.D.; Renault, C.E.; Crowe, B.M.

    1991-03-01

    Volcanic hazard studies for high-level radioactive waste isolation in the Yucca Mountain area, Nevada, require a detailed understanding of Quaternary volcanism to forecast rates of volcanic processes. Recent studies of the Quaternary Cima volcanic fields in southern California have demonstrated that K-Ar dates of volcanic landforms are consistent with their geomorphic and pedologic properties. The systematic change of these properties with time may be used to provide age estimates of undated or questionably dated volcanic features. The reliability of radiometric age determinations of the youngest volcanic center, Lathrop Wells, near the proposed Yucca Mountain site in Nevada has been problematic. In this study, a comparison of morphometric, pedogenic, and stratigraphic data establishes that correlation of geomorphic and soil properties between the Cima volcanic field and the Yucca Mountain area is valid. Comparison of the Lathrop Wells cinder cone to a 15-20 ka cinder cone in California shows that their geomorphic-pedogenic properties are similar and implies that the two cones are of similar age. The authors of ca. 0.27 Ma for the latest volcanic activity at Lathrop Wells, approximately 20 km from the proposed repository, may be in error by as much as an order of magnitude and that the most recent volcanic activity is no older than 20 ka.

  11. Geomorphic assessment of late Quarternary volcanism in the Yucca Mountain area, southern Nevada: Implication for the proposed high-level radiocative waste repository

    SciTech Connect

    Wells, S.G.; McFadden, L.D.; Renault, C.E.; Crowe, B.M.

    1990-06-01

    Volcanic hazard studies for high-level radioactive waste isolation in the Yucca Mountain area, Nevada, require a detailed understanding of Quaternary volcanism to forecast rates of volcanic processes. Recent studies of the Quaternary Cima volcanic field in southern California have demonstrated that K-Ar dates of volcanic landforms are consistent with their geomorphic and pedologic properties. The systematic change of these properties with time may be used to provide age estimates of undated or questionably dated volcanic features. The reliability of radiometric age determinations of the youngest volcanic center, Lathrop Wells, near the proposed Yucca Mountain site in Nevada has been problematic. In this study, a comparison of morphometric, pedogenic, and stratigraphic data establishes that correlation of geomorphic and soil properties between the Cima volcanic field and the Yucca Mountain area is valid. Comparison of the Lathrop Wells cinder cone to a 15-20 ka cinder cone in California shows that their geomorphic-pedogenic properties are similar and implies that the two cones are of similar age. We conclude that previous determinations of ca. 0.27 Ma for the latest volcanic activity at Lathrop Wells, approximately 20 km from the proposed repository, may be in error by as much as an order of magnitude and that the most recent volcanic activity is no older than 20ka.

  12. An integrated approach to population and human resources development planning: a suggested framework for the Sudan.

    PubMed

    Ertur, O S; House, W J

    1993-01-01

    This article describes why greater attention needs to be given to the role of demographic phenomena in creating Sudan's current economic crisis. While state planning and direct involvement in the economy may be on the decline throughout Africa, the public sector cannot simply stop taking any responsibility for planning and policy-making in the domains of population and human resources development. The current nature and scope of population and human resources planning in the Sudan is evaluated and a description given of the machinery and institutions involved in the planning process. Their overall effectiveness is assessed. A broad framework based upon a socioeconomic and demographic system relevant to the objectives of human resources development is presented, with the proposed framework identifying the institutions responsible for creating and monitoring plans for human resources development. PMID:12293641

  13. Pharmaceutical representatives' beliefs and practices about their professional practice: a study in Sudan.

    PubMed

    Idris, K M; Mustafa, A F; Yousif, M A

    2012-08-01

    Pharmaceutical representatives are an important promotional tool for pharmaceutical companies. This cross-sectional, exploratory study aimed to determine pharmaceutical representatives' beliefs and practices about their professional practice in Sudan. A random sample of 160 pharmaceutical representatives were interviewed using a pretested questionnaire. The majority were male (84.4%) and had received training in professional sales skills (86.3%) and about the products being promoted (82.5%). Only 65.6% agreed that they provided full and balanced information about products. Not providing balanced information was attributed by 23.1% to doctors' lack of time. However, 28.1% confessed they sometimes felt like hiding unfavourable information, 21.9% were sometimes or always inclined to give untrue information to make sales and 66.9% considered free gifts as ethically acceptable. More attention is needed to dissemination of ethical codes of conduct and training about the ethics of drug promotion for pharmaceutical representatives in Sudan. PMID:23057370

  14. Integrated vector management: a critical strategy for combating vector-borne diseases in South Sudan

    PubMed Central

    2013-01-01

    Background Integrated vector management (IVM) based vector control is encouraged by the World Health Organization (WHO). However, operational experience with the IVM strategy has mostly come from countries with relatively well-established health systems and with malaria control focused programmes. Little is known about deployment of IVM for combating multiple vector-borne diseases in post-emergency settings, where delivery structures are less developed or absent. This manuscript reports on the feasibility of operational IVM for combating vector-borne diseases in South Sudan. Case description A methodical review of published and unpublished documents on vector-borne diseases for South Sudan was conducted via systematic literature search of online electronic databases, Google Scholar, PubMed and WHO, using a combination of search terms. Additional, non-peer reviewed literature was examined for information related to the subject. Discussion South Sudan is among the heartlands of vector-borne diseases in the world, characterized by enormous infrastructure, human and financial resource constraints and a weak health system against an increasing number of refugees, returnees and internally displaced people. The presence of a multiplicity of vector-borne diseases in this post-conflict situation presents a unique opportunity to explore the potential of a rational IVM strategy for multiple disease control and optimize limited resource utilization, while maximizing the benefits and providing a model for countries in a similar situation. Conclusion The potential of integrating vector-borne disease control is enormous in South Sudan. However, strengthened coordination, intersectoral collaboration and institutional and technical capacity for entomological monitoring and evaluation, including enforcement of appropriate legislation are crucial. PMID:24156749

  15. Levels of pesticides residues in the White Nile water in the Sudan.

    PubMed

    Nesser, Gibreel A A; Abdelbagi, Azhari O; Hammad, Ahmed Mohammed Ali; Tagelseed, Mirghani; Laing, Mark D

    2016-06-01

    Twenty-two commonly used pesticides were monitored during autumn, winter, and summer of 2004-2005 in 27 water samples from three sites along the White Nile in Sudan (former Sudan). Sites were selected to reflect pesticides gathered from drainage canals in central Sudan and from upstream sources. Collected samples were extracted and subjected to gas chromatographic analysis. Pesticides levels were measured in nanograms per liter. Pesticides residues were detected in 96 % of the samples with a total residue burden of 4132.6 ng L(-1), and an overall mean concentration and range of 50.99 and not detected-1570 ng L(-1), respectively. Ororganochlorines were the most frequently detected contaminants, which were found in 70 % of the samples, causing a total burden of 2852.8 ng L(-1), followed by pyrethroids 15 % of the samples, with a total burden of 926.5 ng L(-1). The tested herbicides were detected in ˂4 % of the samples with a total burden of 353.3 ng L(-1), while organophosphorus levels were below the detection limit. The most frequent contaminants were the following: heptachlor and its epoxide (52 % of samples), followed by DDTs (dichlorodiphenyltrichloroethanes) (DDT and DDE, in 19 % of the samples), cypermethrin and fenvalerate (in 11 % of the samples), and pendimethalin (in <4 % of the samples). Residues of hexachlorocyclohexane (HCH) isomers (α, β, γ and δ), endosulfan (α and β), p, p-DDD, λ cyhalothrin, deltamethrin, and oxyfluorfen were not detected in the analyzed samples. Generally, levels were least in autumn, and followed by summer and winter. Sources of contamination might include agricultural lands in central Sudan and upstream sources. Both recent and old contaminations were indicated. PMID:27230426

  16. Sudan stain of fecal fat: new insight into an old test.

    PubMed

    Khouri, M R; Huang, G; Shiau, Y F

    1989-02-01

    The 72-h fecal fat determination is used as the gold standard to document the presence of steatorrhea. Although the Sudan stain for fecal fat is advocated as a sensitive screening test, a quantitative correlation between the 72-h fecal fat quantitation and the fecal Sudan stain is lacking. This study was designed to examine the staining properties of different classes of purified lipids in an experimentally defined artificial matrix, and to elucidate the reasons for the lack of quantitative correlation between these two tests. Our results indicate that the "neutral fat" stain without acidification or heating identifies triglyceride; and at an appropriate pH, the "neutral stain" also identifies fatty acid. The "split fat" stain with acidification and heating identifies both triglyceride and fatty acid. After acidification, fatty acid soaps are converted to the nonionized fatty acid. Thus, fatty acid soaps can be identified indirectly as fat droplets that are stained by the split fat stain. Although cholesterol is stained with Sudan stain after heating, upon cooling, cholesterol forms crystals of anhydrous cholesterol, making its staining pattern distinct. Neither the neutral fat nor the split fat stain can detect phospholipid or cholesteryl ester. The 72-h fecal fat determination is a measure of the total fatty acid content after a specimen is saponified. The resulting fatty acids are derived from a variety of endogenous and exogenous sources, including free fatty acids, soaps of fatty acids, triglycerides, cholesterol esters, and phospholipids. Therefore, the 72-h fecal fat quantitation does not differentiate between the primary sources of the measured fatty acid. It is concluded that the 72-h fecal fat determination is not specific for documenting triglyceride (fat) malabsorption. Until new methods are developed that specifically measure fecal triglyceride and fatty acid, the Sudan stain of fecal fat appears to be a more specific method for detecting the presence of triglyceride and fatty acid in a matrix. PMID:2463205

  17. A new substrate for surface enhanced Raman scattering of dye Sudan molecules.

    PubMed

    Zhou, Xiaofang; Fang, Yan; Zhang, Pengxiang

    2007-05-01

    A new SERS substrate was prepared using electro-polishing aluminum foils. Based on these high active SERS systems, surface enhanced Raman scattering (SERS) of Azo Dye Sudan were performed and carefully studied based on this highly active SERS substrate. High quality SERS spectra were obtained, which indicates that this kind of coarse aluminum foils is an active SERS substrate. Numbers of additional modes were presented, as well as some split peaks, which may be a consequence of symmetry lowering. PMID:16945577

  18. Confluence of the White and Blue Nile Rivers at Khartoum, Sudan

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Blue Nile River flowing from Lake Tana to the east and the larger White Nile River flowing from the Rift Valley region combine to form the Nile River at Khartoum, the capital city of Sudan (15.5N, 33.0E). The rivers normally flow out of phase as a result of the differing maximum precipitation periods of their watersheds. The differing flow periods allows longer use of the river for agriculture irrigation in the fields south of the city.

  19. Competition between Culex quinquefasciatus Say and Anopheles arabiensis patton in the Khartoum area, Sudan

    NASA Astrophysics Data System (ADS)

    El Rayah, El Amin; Abu Groun, Nawal A.

    1983-03-01

    The range of environmental temperatures that allow of survival would appear to be greater for Anopheles arabiensis than for Culex quinquefasciatus. Nevertheless the latter is the more common species in the Khartoum (Sudan) area. This relative abundance is suggested to be attributed largely to the success of Culex quinquefasciatus in exploiting a wide range of breeding sites, even those which are obviously contaminated in various ways.

  20. Extensive permethrin and DDT resistance in Anopheles arabiensis from eastern and central Sudan

    PubMed Central

    2011-01-01

    Background The distribution of insecticide treated nets (ITN) has been dramatically scaled up in eastern and central Sudan. Resistance to insecticides has already been reported in this region and there is an urgent need to develop appropriate resistance management strategies, which requires detailed information on the extent and causes of resistance. This study assessed resistance to permethrin and DDT in seven populations of Anopheles arabiensis from Sudan. Results Three out of the seven populations were defined as resistant to permethrin and five of six populations resistant to DDT according to WHO criteria. The 1014F kdr allele was present in all six populations tested and the presence of this allele was significantly correlated with resistance to permethrin (P = 0.0460). While homozygous 1014F individuals were statistically not more likely to survive (53.7%) permethrin than to be killed (38.6%) by the diagnostic dose, there was no difference in the likelihood of permethrin survival in heterozygotes (P = 0.7973). The susceptible genotypes were more likely to be killed by permethrin exposure than to survive (P = 0.0460). The 1014F allele failed to confer a survival advantage to the WHO diagnostic dose of DDT in either the homozygous or heterozygous state. The 1014S allele was not detected in any of the populations tested. Conclusion The kdr allele is certainly contributing to the extensive resistance to permethrin and DDT in Sudan but the high number of DDT (43%) and permethrin (16.7%) survivors that did not contain either kdr alleles suggests that other resistance mechanisms are also present in these populations. The high frequency of permethrin resistance throughout central and eastern Sudan is a cause of great concern for malaria control activities. PMID:21812972

  1. C. 1.5 Ga metamorphism of the Lazdijai 13 volcano-sedimentary sequence in southern Lithuania: its origin and implications

    NASA Astrophysics Data System (ADS)

    Siliauskas, Laurynas; Skridlaite, Grazina

    2015-04-01

    The concealed crystalline crust in the SW East European Craton consists of several domains finally accreted at 1.8-1.70 Ga (Bogdanova et al., 2014). However, some geological structures in the Lithuanian basement are still poorly reconstructed because of insufficient isotopic and geochemical data. Such is the Lazdijai 13 (Lz13) volcano-sedimentary sequence in southern Lithuania, preliminary dated at 1.83-1.80 Ga (U-Pb zircon age). The newly obtained monazite analyses (EPMA dating, Cameca SX-100 electron microprobe, Warsaw University) allowed dating of metamorphism of the Lz13 rocks. The 300 m thick Lz13 sequence is composed of deformed and metamorphosed volcanics, volcano-clastics and sediments, cross-cut by pegmatite and quartz veins. The upper part of the drilling (at c. 493 m) consists of exhalitic quartz chlorite cherts and metaandesitic rocks. They are underlain by medium-fine grained shists composed of quartz, biotite, garnet, cordierite, staurolite, minor plagioclase, K-feldspar, magnetite and monazite (felsic volcanics, 540 m) that were metamorphosed at 580° C and 6 kbar (garnet, biotite, cordierite geothermobarometry). Monazites are small, interstitial, fragmented and dissolved, some found as inclusions in magnetite. They yielded three ages: 1685±25 Ma, 1525±11Ma, and 1448±24 Ma. Another layer of a fine grained shist (quartz, biotite, garnet, K-feldspar, muscovite, 599 m) of sedimentary origin contains zircons and monazites arranged in thin, undulating lines. The monazites are small, interstitial, partly dissolved, in places overgrown by alanite aggregates. They yielded 1671±29 Ma and 1523±17 Ma ages. Below, at 757 m, a strongly deformed shist composed of quartz, biotite, K-feldspar, plagioclase, garnet and cordierite (former sediment) was metamorphosed at 498° C and 5.4 kbar (garnet, biotite, plagioclase and muscovite geothermobarometry). It contains very small, strongly dissolved and locally overgrown by alanite, monazite grains. Three of them were dated at 1629±48 Ma and 1499±21 Ma. The 1685-1629 Ma ages were obtained from relic domains in the c 1.5 Ga monazites. These domains might be the relics of magmatic monazites, somewhat older than 1.69 Ga. The largest monazite group of c. 1530-1500 Ma seems to record a major metamorphic event. The c. 1450 Ma age might indicate a cooling or lead loss as in case of the oldest monazites. According to the previously obtained data, the volcano-sedimentary sequence of Lz13 might have been formed in a back arc tectonic setting c. 1.83-1.80 Ga ago. The new data shows that the rocks did not experience any stronger metamorphic reworking until c. 1.5 Ga. The nearby AMCG charnockites and host rocks were metamorphosed at 1.53-1.50 Ga (Skridlaite et al., 2008). The metamorphism might have been caused by the intrusion of the 1.54-1.50 Ga AMCG Mazury suite in N Poland and S Lithuania. The Mesoproterozoic AMCG magmatism and metamorphism in Lithuania as well as in Poland may be regarded as inboard manifestations of the accretionary Danopolonian orogeny (Bogdanova, 2008) at the present southern margin of ProtoBaltica. This is a contribution to the Open Access Centre activities Bogdanova, S.V. et al., 2008, Precambrian Research, 160, 23-45. Bogdanova, S., et al., 2014, Precambrian Research, http://dx.doi.org/10.1016/j.precamres.2014.11.023 Skridlaite, et al., 2008. Gondwana Research, 14, 663-674.

  2. Long Return Periods for Earthquakes in San Gorgonio Pass and Implications for Large Ruptures of the San Andreas Fault in Southern California

    NASA Astrophysics Data System (ADS)

    Yule, J.; McBurnett, P.; Ramzan, S.

    2011-12-01

    The largest discontinuity in the surface trace of the San Andreas fault occurs in southern California at San Gorgonio Pass. Here, San Andreas motion moves through a 20 km-wide compressive stepover on the dextral-oblique-slip thrust system known as the San Gorgonio Pass fault zone. This thrust-dominated system is thought to rupture during very large San Andreas events that also involve strike-slip fault segments north and south of the Pass region. A wealth of paleoseismic data document that the San Andreas fault segments on either side of the Pass, in the San Bernardino/Mojave Desert and Coachella Valley regions, rupture on average every ~100 yrs and ~200 yrs, respectively. In contrast, we report here a notably longer return period for ruptures of the San Gorgonio Pass fault zone. For example, features exposed in trenches at the Cabezon site reveal that the most recent earthquake occurred 600-700 yrs ago (this and other ages reported here are constrained by C-14 calibrated ages from charcoal). The rupture at Cabezon broke a 10 m-wide zone of east-west striking thrusts and produced a >2 m-high scarp. Slip during this event is estimated to be >4.5 m. Evidence for a penultimate event was not uncovered but presumably lies beneath ~1000 yr-old strata at the base of the trenches. In Millard Canyon, 5 km to the west of Cabezon, the San Gorgonio Pass fault zone splits into two splays. The northern splay is expressed by 2.5 ± 0.7 m and 5.0 ± 0.7 m scarps in alluvial terraces constrained to be ~1300 and ~2500 yrs old, respectively. The scarp on the younger, low terrace postdates terrace abandonment ~1300 yrs ago and probably correlates with the 600-700 yr-old event at Cabezon, though we cannot rule out that a different event produced the northern Millard scarp. Trenches excavated in the low terrace reveal growth folding and secondary faulting and clear evidence for a penultimate event ~1350-1450 yrs ago, during alluvial deposition prior to the abandonment of the low terrace. Subtle evidence for a third event is poorly constrained by age data to have occurred between 1600 and 2500 yrs ago. The southern splay at Millard Canyon forms a 1.5 ± 0.1 m scarp in an alluvial terrace that is inset into the lowest terrace at the northern Millard site, and therefore must be < ~1300 yrs old. Slip on this fault probably occurred during the most recent rupture in the Pass. In summary, we think that the most recent earthquake occurred 600-700 yrs ago and generated ~6 m of slip on the San Gorgonio Pass fault zone. The evidence for two older earthquakes is less complete but suggests that they are similar in style and magnitude to the most recent event. The available data therefore suggest that the San Gorgonio Pass fault zone has produced three large (~6 m) events in the last ~2000 yrs, a return period of ~700 yrs assuming that the next rupture is imminent. We prefer a model whereby a majority of San Andreas fault ruptures end as they approach the Pass region from the north or the south (like the Wrightwood event of A.D. 1812 and possibly the Coachella Valley event of ~A.D. 1680). Relatively rare (once-per-millennia?), through-going San Andreas events break the San Gorgonio Pass fault zone and produce the region's largest earthquakes.

  3. The evolution of the Hornelen Basin detachment system, western Norway: Implications for the style of late orogenic extension in the southern Scandinavian Caledonides

    NASA Astrophysics Data System (ADS)

    Wilks, W. J.; Cuthbert, S. J.

    1994-11-01

    The geology of the Devonian Hornelen Basin and the surrounding Western Gneiss Region (WGR), western Norway has been examined in detail. Structural, clast provenance and geothermobarometric data have been combined to reconstruct the motion history of part of a major late-orogenic extensional shear zone in the southern Scandinavian Caledonides, the Nordfjord-Sogn Detachment (NSD). The NSD in the Hornelen Basin area is a zone of mylonites 4-6 km thick, tectonostratigraphically constrained within the Lower and Middle Allochthons (LMA) and the uppermost part of the WGR. It separates eclogite-bearing gneisses of the WGR from greenschist and amphibolite facies rocks of the Middle and Upper Allochthons, marking a profound metamorphic break and indicating major excision of crustal section. Kinematic indicators give a consistent "top to the west" shear sense, indicating a reversal of the movement sense of the Scandian nappes, with the ductile strain being distributed through the entire LMA section. The WGR was exhumed from depths of up to 100 km in the footwall of the shear zone, partly aided by pure-shear vertical flattening below the NSD and extension and erosion of the hanging wall. The majority of the movements on the NSD in the Hornelen Basin area occurred under amphibolite facies conditions prior to 410 Ma. Subsequent shear caused limited greenschist retrogression along extensional crenulation cleavages. Depending on interpretation of mica 40Ar- 39Ar ages, this lower-grade shearing may be due to a continuation of movements, or renewal of motion associated with opening of the Hornelen Basin at about 385 Ma. The lack of clear evidence of penetrative greenschist facies mylonites in the Hornelen area may be due to the faulted omission of tectonites of this grade. Following Scandian A-subduction and eclogite facies metamorphism at 425 Ma, the P-T-t path of the WGR shows very rapid decompression associated with early slip on the extensional detachment horizons. Unroofing was initially near isothermal, followed by a phase of rapid near-isobaric cooling. After 410 Ma decompression and cooling slowed, as slip on the NSD slowed or even ceased. By the Middle Devonian, the WGR lay at about 10-15 km depth and the crust had almost returned to isostatic equilibrium. At this time, a brittle fault, splaying from the NSD, ramped upwards through the Upper Allochthon, opening a scoop-shaped, west-facing half-graben, the Hornelen Basin. A further 50 km of heave on the NSD occurred during alluvial infilling of the basin. Subsequently, the basin fill was folded by (Late Devonian?) N-S compression and the basin margins were modified by Mesozoic faulting. These features are consistent with an orogenic collapse model for southern Scandinavia that involves large-scale backsliding of the Scandinavian Caledonides within tectonostratigraphic units. By this mechanism the Baltic Shield could have been efficiently unloaded, with tectonic translations producing significant metamorphic breaks within a seemingly preserved tectonostratigraphic sequence. The model favours orogenic collapse driven by an external pull, rather than internal body forces.

  4. A 250,000-year record of lunette dune accumulation on the Southern High Plains, USA and implications for past climates

    NASA Astrophysics Data System (ADS)

    Rich, Julie

    2013-02-01

    A concentration of lake/playa basins occurs on the Southern High Plains (SHP) of northwest Texas and eastern New Mexico. Associated with these lake/playas are lee-side lunettes positioned on their southeast margins ranging in height from 1.5 to >10 m. An OSL dating program was applied to 30 samples from lunettes associated with large lakes and small playa basins. Samples were extracted from trenched dune sections or from deep cores. Earlier SHP lunette investigations show depositional ages primarily in the late Wisconsin and Holocene. This research extends the timing of lunette accretion to the middle Pleistocene, the earliest recorded deposition for these features. The expanded chronology permitted investigation into dune morphology on nested lunettes built on contracting lake margins. Outer lunettes formed prior to inner dunes, but simultaneous deposition occurred on downwind ridges as younger lee-side dunes were constructed. Large lake lunettes were inactive during discreet SHP pluvial episodes from early Wisconsin to LGM. Conversely, these lunettes accreted when climatic conditions promoted basin desiccation and aeolian deflation. This suggests their mode of formation contrasts with lunette models recognized for other regions. From post LGM to earliest Holocene, active lunette accretion occurred from 16 to 11 ka followed by a significant period of lunette construction during the mid-Holocene. Late Holocene-lunette deposition was interrupted by intervals of landscape stability. Lunette deposition between 1300s and 1700s corresponds with drought intervals recognized in tree-ring records from adjacent regions. Recent lunette activity on the plateau is contemporary with the 1930's 'dust bowl'. Further insight into SHP response to changing climatic conditions was given by comparing lunette depositional events with previous investigations on sedimentation intervals for draws, lake/playa basins, and sand sheets.

  5. Deciphering shallow paleomagnetic inclinations: 2. Implications from Late Cretaceous strata overlapping the Insular/Intermontane Superterrane boundary in the southern Canadian Cordillera

    NASA Astrophysics Data System (ADS)

    Enkin, R. J.; Mahoney, J. B.; Baker, J.; Riesterer, J.; Haskin, M. L.

    2003-04-01

    Significant discrepancies exist between paleomagnetic and geologic estimates of the timing and magnitude of terrane displacement in the southern Canadian Cordillera. Lithostratigraphic, palynological, geochronologic, geochemical, and structural data, to which we add paleomagnetic data, demonstrate that Upper Cretaceous strata in Churn Creek are laterally equivalent facies of the Silverquick/Powell Creek (SPC) succession. These rocks therefore comprise a single overlap sequence linking the Insular and Intermontane Superterranes by Late Albian-Cenomanian time (˜95 Ma), contradicting previous assertions based solely on paleomagnetic interpretation that major (˜2000 km) latitudinal displacement separated the two regions. The Churn Creek succession retains primary magnetic remanence, as demonstrated by positive fold, conglomerate and contact tests. The sediments do not hold the anisotropy signature of compaction-shallowed inclinations. The mean inclination of all SPC sites, from both Mount Tatlow and Churn Creek, is 55.6° ± 2.3° (N = 36 sites), corresponding to a paleolatitude of 36.1° ± 2.4°. This reflects northward translation of the composite Insular/Intermontane Superterrane of 3050 ± 450 km between 85 and 50 Ma. The Silverquick/Powell Creek succession at Churn Creek unconformably overlies the northern end of the Spences Bridge Group, a late Early Cretaceous volcanic arc assemblage on the Intermontane Superterrane. Paleomagnetic data in the companion paper place it 1050 ± 450 km south of its current position between 100 and 105 Ma. Integration of these new data sets require that the Insular and Intermontane Superterranes formed a single, enormous crustal block that underwent complex, episodic south-north translation between circa 105 and 50 Ma. The timing, rate, and vectors of translation are problematic in terms of geologic constraints along the continental margin.

  6. Deciphering shallow paleomagnetic inclinations: 1. Implications from correlation of Albian volcanic rocks along the Insular/Intermontane Superterrane boundary in the southern Canadian Cordillera

    NASA Astrophysics Data System (ADS)

    Haskin, M. L.; Enkin, R. J.; Mahoney, J. B.; Mustard, P. S.; Baker, J.

    2003-04-01

    Geologic and paleomagnetic data lead to two contradictory hypotheses regarding the paleoposition of the Insular and Intermontane Superterranes that presently constitute the western Canadian Cordillera. Paleomagnetic data from the Insular and Intermontane superterranes suggest a southerly origin coinciding with the latitude of Mexico and the northwest United States, respectively, during the mid-Cretaceous. Geologic evidence points to a northerly origin for these same tectonic entities during this period; both models cannot be correct. Geologic and paleomagnetic data from the Empire Valley-Churn Creek area in south central British Columbia (51.5°N, 122.5°W) are critical to resolving these contradictory hypotheses. Late Cretaceous rocks correlated to the Insular Superterrane with large paleomagnetic displacements unconformably overlie mid-Cretaceous rocks correlative to the Spences Bridge Group of the Intermontane Superterrane. We provide paleomagnetic evidence of this correlation based on similar magnetic properties, opaque mineral assemblages, demagnetization behavior, fold test results, mean inclinations, clockwise vertical axes rotations, and statistically indistinguishable paleomagnetic poles and displacement estimates. This correlation and the observed geologic relationships in the Empire Valley-Churn Creek area indicate that the Insular and Intermontane Superterranes were linked by the mid-Cretaceous. Sites from the two previous Spences Bridge Group studies are combined with their correlatives in the Empire Valley-Churn Creek area to give 81 sites that yield a paleomagnetic pole of 60.5°N, 304.5°E, dp = 3.7°, dm = 5.5° which corresponds to 1050 ± 450 km of displacement from the south. This new displacement estimate suggests that the Spences Bridge arc formed at the latitude of southern Oregon during the mid-Cretaceous.

  7. Age and composition of Archean crystalline rocks from the southern Madison Range, Montana. Implications for crustal evolution in the Wyoming craton

    SciTech Connect

    Mueller, P.A.; Shuster, R.D. ); Wooden, J.L. ); Erslev, E.A. ); Bowes, D.R. )

    1993-04-01

    The southern Madison Range of southwestern Montana contains two distinct Precambrian lithologic assemblages: (1) a complex of tonalitic to granitic gneisses that has been thrust over (2) a medium-grade metasupracrustal sequence dominated by pelitic schist. Crystallization ages for the protolith of a granodioritic gneiss that intruded the metasupracrustal sequence ([approximately]2.6 Ga)-along with an intercalated meta-andesite ([approximately]2.7 Ga) confirm the sequence as Archean. Chemical (major and trace element), isotopic (Rb-Sr, Sm-Nd, Pb-Pb), and geochronologic (U-Pb zircon) data for selected components of the gneiss complex indicate two groups of gneisses: an older, tonalitic to trondhjemitic group ([approximately]3.3 Ga) and a younger, mostly granitic group ([approximately]2.7 Ga). Both groups of gneisses exhibit the radiogenic Pb and nonradiogenic Nd isotopic signature characteristic of Middle and Late Archean rocks from throughout the Wyoming province. The older gneisses, in particular, appear to be compositionally, isotopically, and chronologically comparable to other Middle Archean gneisses from the northern part of the province (for example, Beartooth Mountains). The Late Archean gneisses, however, exhibit some distinct differences relative to their temporal counterparts, including (1) trace-element patterns that are more suggestive of crustal melts than subduction activity and (2) higher initial Sr isotopic ratios that suggest more involvement of older crust in their petrogenesis. These comparisons suggest that the juxtaposition of Late Archean terranes in the northern Wyoming province was the result, at least in part, of intracratonic processes. 41 refs., 6 figs., 2 tabs.

  8. Genesis of an esker-like ridge over the southern Fraser Plateau, British Columbia: Implications for paleo-ice sheet reconstruction based on geomorphic inversion

    NASA Astrophysics Data System (ADS)

    Perkins, Andrew J.; Brennand, Tracy A.; Burke, Matthew J.

    2013-05-01

    Robust interpretations of meltwater systems operating during ice sheet decay are integral to reconstructing deglacial patterns and style. Yet over reliance on meltwater landform morphology with limited attention to morpho-sedimentary relationships, and basin-scale geomorphic and stratigraphic context can lead to unreliable geomorphic inversion-based paleo-ice sheet reconstructions. This problem is illustrated by the evolution of Young Lake esker-like ridge (YLER) formed in the Young Lake basin (YLB) on BC's southern Fraser Plateau during decay of the last Cordilleran Ice Sheet (CIS). We integrate data from digital elevation models, aerial photographs, sedimentary outcrops, water wells and shallow geophysics (ground-penetrating radar, electrical resistivity tomography). Previous interpretations of YLER as both an esker and an ice-contact, poorly-sorted, stratified deposit emplaced by westerly flowing meltwater, imply an eastward retreating ice margin. Geophysical data from a flat-topped component of YLER reveal slipface and planar-bedded sand and gravel overlying lacustrine sediments, characteristic of a Hjulstrom delta. Eastward-dipping foresets in a Gilbert delta exist at the eastern terminus. Contextually our observations suggest, despite esker-like morphology, YLER was not deposited within a subglacial ice tunnel. Instead, it formed through deposition of subaerial outwash between and/or on dead ice in front of a regionally backwasting ice margin. The complex deglacial evolution of YLB, including a drainage reversal and formation of two glacial lakes, supports northwestward backwasting of the CIS and dead ice within YLB. We conclude that accurate geomorphic inversion of meltwater landforms for deglacial paleo-ice sheet reconstruction requires knowledge of landform-scale morpho-sedimentary relationships and basin-scale geomorphic and stratigraphic context.

  9. Leafcutter Bee Nests and Pupae from the Rancho La Brea Tar Pits of Southern California: Implications for Understanding the Paleoenvironment of the Late Pleistocene

    PubMed Central

    Holden, Anna R.; Koch, Jonathan B.; Griswold, Terry; Erwin, Diane M.; Hall, Justin

    2014-01-01

    The Rancho La Brea Tar Pits is the world’s richest and most important Late Pleistocene fossil locality and best renowned for numerous fossil mammals and birds excavated over the past century. Less researched are insects, even though these specimens frequently serve as the most valuable paleoenvironemental indicators due to their narrow climate restrictions and life cycles. Our goal was to examine fossil material that included insect-plant associations, and thus an even higher potential for significant paleoenviromental data. Micro-CT scans of two exceptionally preserved leafcutter bee nest cells from the Rancho La Brea Tar Pits in Los Angeles, California reveal intact pupae dated between ∼23,000–40,000 radiocarbon years BP. Here identified as best matched to Megachile (Litomegachile) gentilis Cresson (Hymenoptera: Megachilidae) based on environmental niche models as well as morphometrics, the nest cells (LACMRLP 388E) document rare preservation and life-stage. The result of complex plant-insect interactions, they offer new insights into the environment of the Late Pleistocene in southern California. The remarkable preservation of the nest cells suggests they were assembled and nested in the ground where they were excavated. The four different types of dicotyledonous leaves used to construct the cells were likely collected in close proximity to the nest and infer a wooded or riparian habitat with sufficient pollen sources for larval provisions. LACMRLP 388E is the first record of fossil Megachile Latreille cells with pupae. Consequently, it provides a pre-modern age location for a Nearctic group, whose phylogenetic relationships and biogeographic history remain poorly understood. Megachile gentilis appears to respond to climate change as it has expanded its distribution across elevation gradients over time as estimated by habitat suitability comparisons between low and high elevations; it currently inhabits mesic habitats which occurred at a lower elevation during the Last Glacial Maximum ∼21,000 years ago. Nevertheless, the broad ecological niche of M. gentilis appears to have remained stable. PMID:24718701

  10. Basin geometry and cumulative offsets in the Eastern Transverse Ranges, southern California: Implications for transrotational deformation along the San Andreas fault system

    USGS Publications Warehouse

    Langenheim, V.E.; Powell, R.E.

    2009-01-01

    The Eastern Transverse Ranges, adjacent to and southeast of the big left bend of the San Andreas fault, southern California, form a crustal block that has rotated clockwise in response to dextral shear within the San Andreas system. Previous studies have indicated a discrepancy between the measured magnitudes of left slip on through-going east-striking fault zones of the Eastern Transverse Ranges and those predicted by simple geometric models using paleomagnetically determined clockwise rotations of basalts distributed along the faults. To assess the magnitude and source of this discrepancy, we apply new gravity and magnetic data in combination with geologic data to better constrain cumulative fault offsets and to define basin structure for the block between the Pinto Mountain and Chiriaco fault zones. Estimates of offset from using the length of pull-apart basins developed within left-stepping strands of the sinistral faults are consistent with those derived by matching offset magnetic anomalies and bedrock patterns, indicating a cumulative offset of at most ???40 km. The upper limit of displacements constrained by the geophysical and geologic data overlaps with the lower limit of those predicted at the 95% confidence level by models of conservative slip located on margins of rigid rotating blocks and the clockwise rotation of the paleomagnetic vectors. Any discrepancy is likely resolved by internal deformation within the blocks, such as intense deformation adjacent to the San Andreas fault (that can account for the absence of basins there as predicted by rigid-block models) and linkage via subsidiary faults between the main faults. ?? 2009 Geological Society of America.

  11. Evidence for Late-Paleozoic brine migration in Cambrian carbonate rocks of the central and southern Appalachians: Implications for Mississippi Valley-type sulfide mineralization

    USGS Publications Warehouse

    Hearn, P.P., Jr.; Sutter, J.F.; Belkin, H.E.

    1987-01-01

    Many Lower Paleozoic limestones and dolostones in the Valley and Ridge province of the central and southern Appalachians contain 10 to 25 weight percent authigenic potassium feldspar. This was considered to be a product of early diagenesis, however, 40Ar 39Ar analyses of overgrowths on detrital K-feldspar in Cambrian carbonate rocks from Pennsylvania, Maryland, Virginia, and Tennessee yield Late Carboniferous-Early Permian ages (278-322 Ma). Simple mass balance calculations suggest that the feldspar could not have formed isochemically, but required the flux of multiple pore volumes of fluid through the rocks, reflecting regional fluid migration events during the Late-Paleozoic Alleghanian orogeny. Microthermometric measurements of fluid inclusions in overgrowths on detrital K-feldspar and quartz grains from unmineralized rocks throughout the study area indicate homogenization temperatures from 100?? to 200??C and freezing point depressions of -14?? to -18.5??C (18-21 wt.% NaCl equiv). The apparent similarity of these fluids to fluid inclusions in ore and gangue minerals of nearby Mississippi Valley-type (MVT) deposits suggests that the regional occurrences of authigenic K-feldspar and MVT mineralization may be genetically related. This hypothesis is supported by the discovery of authigenic K-feldspar intergrown with sphalerite in several mines of the Mascot-Jefferson City District, E. Tennessee. Regional potassic alteration in unmineralized carbonate rocks and localized occurrences of MVT mineralization are both explainable by a gravity-driven flow model, in which deep brines migrate towards the basin margin under a hydraulic gradient established during the Alleghanian orogeny. The authigenic K-feldspar may reflect the loss of K during disequilibrium cooling of the ascending brines. MVT deposits are probably localized manifestations of the same migrating fluids, occurring where the necessary physical and chemical traps are present. ?? 1987.

  12. Evidence for late-paleozoic brine migration in Cambrian carbonate rocks of the central and southern Appalachians: implications for Mississippi Valley-type sulfide mineralization

    SciTech Connect

    Hearn, P.P. Jr; Sutter, J.F.; Belkin, H.E.

    1987-05-01

    Many Lower Paleozoic limestones and dolostones in the Valley and Ridge province of the central and southern Appalachians contain 10 to 25 weight percent authigenic potassium feldspar. This was considered to be a product of early diagenesis, however, /sup 40/Ar//sup 39/Ar analyses of overgrowths on detrital K-feldspar in Cambrian carbonate rocks from Pennsylvania, Maryland, Virginia, and Tennessee yield Late Carboniferous-Early Permian ages (278-322 Ma). Simple mass balance calculations suggest the feldspar could not have formed isochemically, but required the flux of multiple pore volumes of fluid through the rocks, reflecting regional fluid migration events during the Late-Paleozoic Alleghanian orogeny. Microthermometric measurements of fluid inclusions in overgrowths on detrital K-feldspar and quartz grains from unmineralized rocks throughout the study area indicate homogenization temperatures from 100/sup 0/ to 200/sup 0/C and freezing point depressions of -14/sup 0/ to -18.5/sup 0/C. The apparent similarity of these fluids to fluid inclusions in ore and gangue minerals of nearby Mississippi Valley-type (MVT) deposits suggests that the regional occurrences of authigenic K-feldspar and MVT mineralization may be genetically related. This hypothesis is supported by the discovery of authigenic K-feldspar intergrown with sphalerite in several mines of the Mascot-Jefferson City District, E. Tennessee. Regional potassic alteration in unmineralized carbonate rocks and localized occurrences of MVT mineralization are both explainable by a gravity-driven flow model, in which deep brines migrate towards the basin margin under a hydraulic gradient established during the Alleghanian orogeny.

  13. Initial results and implications of [sup 40]Ar/[sup 39]Ar mica age dating in the southern Black Hills, South Dakota

    SciTech Connect

    Holm, D.K.; Dahl, P.S.; Gardner, E.T. . Dept. of Geology); Lux, D.R. . Dept. of Geology)

    1993-04-01

    Intrusion of the 1,700 Ma Harney Peak Granite, southern Black Hills, South Dakota resulted in the formation of a large thermal aureole reaching second-sillimanite grade metamorphism and local migmatization. [sup 40]Ar/[sup 39]Ar ages for micas were obtained from staurolite-zone country rock samples collected over a wide region surrounding the pluton. Excess argon appears to be a problem in only one sample which exhibited a total gas age much older than the pluton. A sample ([number sign]87) located [approximately]15 km SW of the pluton yielded a biotite near-plateau age (and concordant total gas age) of 1,669[+-]16 Ms. Muscovite from the sample yielded a concordant plateau and total gas age of 1,648[+-]12 Ma. The concordant mica pair ages (within error) suggests cooling from above [approximately]350 C to below [approximately]300 C about 30--40 Ma after intrusion of the main pluton. Five separates from three localities (W and NW of the pluton) yield concordant plateau and near-plateau mica ages which cluster around 1,620--1,630 Ma ages as having been reset after initial cooling to below [approximately]300 C at about 1,660 Ma. Since no igneous activity of this age has been reported in the Black Hills, the authors favor a resetting event associated with a low-grade metamorphic event long recognized regionally east and west of the Black Hills and perhaps visibly represented within the Black Hills by a late (post-Harney Peak Granite) widespread but non-penetrative (F4) foliation.

  14. Mineralogy and geochemistry of pseudogley soils and recent alluvial clastic sediments in the Ngog-Lituba region, Southern Cameroon: An implication to their genesis

    NASA Astrophysics Data System (ADS)

    Ndjigui, Paul-Désiré; Ebah Abeng, Sandrine Appolonie; Ekomane, Emile; Nzeukou, Aubin Nzeugang; Ngo Mandeng, Francine Sidonie; Matoy Lindjeck, Marthe

    2015-08-01

    Mineralogical and geochemical investigations have been done on the hydromorphic clays (pseudogley soils and recent alluvial clastic sediments) in the Sanaga Maritime region (Southern Cameroon). Pseudogley soils are developed on gneisses from the Yaoundé Group. They have a dark brown to greyish brown color, with silty clay texture. Their mineral assemblage is made up of kaolinite, goethite, quartz, smectite, rutile, muscovite-illite and feldspars. The alluvial clastic sediments are characterized by variable colors (purple yellow, greenish, dark brown and purple brown) and sandy clay to clay texture. The mineral assemblage of alluvial clays is similar to that of pseudogley soils. SEM observations confirm the presence of kaolinite, smectite, quartz and muscovite-illite. Infrared data show that kaolinite is more orderly in pseudogley than in the alluvial clastic sediments. The Ngog-Lituba gneisses have moderate contents in SiO2, Al2O3, Fe2O3, MgO, CaO, Na2O, K2O and several trace elements including REE. High element depletion is noticed in the pseudogley soils except Cr, V, Zr, Pb and REE. However, the alluvial clays are marked by a strong mobilization of LILE (Na, K, Ba, Rb and Sr) and REE, relative to the parent rock and pseudogley soils. The chondrite-normalized REE patterns are homogenous and parallel with Ce-anomalies. The (La/Yb)N shows that the REE fractionation increase from the parent rock to the alluvial clastic sediments. The mineralogical and geochemical features show that the clastic river sediments are derived from the erosion of the neighboring pseudogley materials before hydraulic sorting.

  15. Evidence for Late-Paleozoic brine migration in Cambrian carbonate rocks of the central and southern Appalachians: Implications for Mississippi Valley-type sulfide mineralization

    NASA Astrophysics Data System (ADS)

    Hearn, Paul P., Jr.; Sutter, John F.; Belkin, Harvey E.

    1987-05-01

    Many Lower Paleozoic limestones and dolostones in the Valley and Ridge province of the central and southern Appalachians contain 10 to 25 weight percent authigenic potassium feldspar. This was considered to be a product of early diagenesis, however, 40Ar /39Ar analyses of overgrowths on detrital K-feldspar in Cambrian carbonate rocks from Pennsylvania, Maryland, Virginia, and Tennessee yield Late Carboniferous-Early Permian ages (278-322 Ma). Simple mass balance calculations suggest that the feldspar could not have formed isochemically, but required the flux of multiple pore volumes of fluid through the rocks, reflecting regional fluid migration events during the Late-Paleozoic Alleghanian orogeny. Microthermometric measurements of fluid inclusions in overgrowths on detrital K-feldspar and quartz grains from unmineralized rocks throughout the study area indicate homogenization temperatures from 100° to 200°C and freezing point depressions of -14° to -18.5°C (18-21 wt.% NaCl equiv). The apparent similarity of these fluids to fluid inclusions in ore and gangue minerals of nearby Mississippi Valley-type (MVT) deposits suggests that the regional occurrences of authigenic K-feldspar and MVT mineralization may be genetically related. This hypothesis is supported by the discovery of authigenic K-feldspar intergrown with sphalerite in several mines of the Mascot-Jefferson City District, E. Tennessee. Regional potassic alteration in unmineralized carbonate rocks and localized occurrences of MVT mineralization are both explainable by a gravity-driven flow model, in which deep brines migrate towards the basin margin under a hydraulic gradient established during the Alleghanian orogeny. The authigenic K-feldspar may reflect the loss of K during disequilibrium cooling of the ascending brines. MVT deposits are pro