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1

Schistosoma hematobium and S. mansoni among Children, Southern Sudan  

PubMed Central

We conducted a survey of schistosomiasis among schoolchildren in 2 villages in Southern Sudan. In Lui (West Equatoria region), prevalence of Schistosoma mansoni infection was 51.5%; no cases of S. hematobium infection were detected. In Nyal (Upper Nile region), prevalence of S. hematobium infection was 73% and S. mansoni infection, 70%. PMID:18257996

Deganello, Roberto; Beltramello, Claudio; Duncan, Otine; Oyugi, Vincent; Montresor, Antonio

2007-01-01

2

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

ERIC Educational Resources Information Center

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…

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

2011-01-01

3

The epidemiology of low vision and blindness associated with trichiasis in southern Sudan  

E-print Network

Abstract Background We investigated vision status associated with trachomatous trichiasis (TT) and explored age-sex patterns of low vision and blindness associated with trichiasis in Mankien district of southern Sudan where trachoma prevention...

Ngondi, Jeremiah; Reacher, Mark; Matthews, Fiona E; Ole-Sempele, Francis; Onsarigo, Alice; Matende, Ibrahim; Baba, Samson; Brayne, Carol; Emerson, Paul M

2007-08-28

4

Reliminary survey of ticks (Acari: Ixodidae) on cattle in Central Equatoria State, Southern Sudan.  

PubMed

In a preliminary survey conducted in 2005, the species composition and seasonality of ticks infesting cattle in Central Equatoria State, Southern Sudan was determined. Three locations were selected (Gumbo, Khor Rumla and Nyaing) and surveyed every 3 months. Two cattle herds in each of the three locations were visited four times during the study period. Total body collections of ticks were made from each of five cattle (Nilotic Zebu breed) kept in six different herds. Four tick genera and ten species were identified. The tick species identified were Amblyomma lepidum, Amblyomma variegatum, Boophilus annulatus, Boophilus decoloratus, Hyalomma marginatum rufipes, Hyalomma truncatum, Rhipicephalus appendiculatus, Rhipicephalus evertsi evertsi, Rhipicephalus praetextatus and Rhipicephalus sanguineus group. The highest number of ticks was collected in October during the rainy season. A finding of great significance was that R. appendiculatus, vector of East Coast fever, has now firmly established itself throughout the year with possible implications for cattle production in Central Equatoria State. PMID:18575063

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

2008-03-01

5

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

PubMed Central

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

Brass, Michael; Schwenniger, Jean-Luc

2013-01-01

6

Epidemiological studies on tick-borne diseases of cattle in Central Equatoria State, Southern Sudan  

Microsoft Academic Search

A herd-based study was carried out in Central Equatoria State, Southern Sudan, to study epidemiological aspects of tick-borne\\u000a diseases. Six herds of cattle situated in three different locations were selected and investigated every 3 months during the\\u000a year 2005. Blood smears for Giemsa staining and blood spots on filter paper for deoxyribonucleic acid extraction were collected\\u000a from 600 apparently healthy indigenous

D. A. Salih; A. M. El Hussein; U. Seitzer; J. S. Ahmed

2007-01-01

7

Prevalence and Causes of Blindness and Low Vision in Southern Sudan  

PubMed Central

Background Blindness and low vision are thought to be common in southern Sudan. However, the magnitude and geographical distribution are largely unknown. We aimed to estimate the prevalence of blindness and low vision, identify the main causes of blindness and low vision, and estimate targets for blindness prevention programs in Mankien payam (district), southern Sudan. Methods and Findings A cross-sectional survey of the population aged 5 y and above was conducted in May 2005 using a two-stage cluster random sampling with probability proportional to size. The Snellen E chart was used to test visual acuity, and participants also underwent basic eye examination. Vision status was defined using World Health Organization categories of visual impairment based on presenting visual acuity (VA). A total of 2,954 persons were enumerated and 2,499 (84.6%) examined. Prevalence of blindness (presenting VA of less than 3/60 in the better eye) was 4.1% (95% confidence interval [CI], 3.4–4.8); prevalence of low vision (presenting VA of at least 3/60 but less than 18/60 in the better eye) was 7.7% (95% CI, 6.7–8.7); whereas prevalence of monocular visual impairment (presenting VA of at least 18/60 in better eye and VA of less than 18/60 in other eye) was 4.4% (95% CI, 3.6–5.3). The main causes of blindness were considered to be cataract (41.2%) and trachoma (35.3%), whereas low vision was mainly caused by trachoma (58.1%) and cataract (29.3%). It is estimated that in Mankien payam 1,154 persons aged 5 y and above (lower and upper bounds = 782–1,799) are blind, and 2,291 persons (lower and upper bounds = 1,820–2,898) have low vision. Conclusions Blindness is a serious public health problem in Mankien, and there is urgent need to implement comprehensive blindness prevention programs. Further surveys are essential to confirm these tragic findings and estimate prevalence of blindness and low vision in the entire region of southern Sudan in order to facilitate planning of VISION 2020 objectives. PMID:17177596

Ngondi, Jeremiah; Ole-Sempele, Francis; Onsarigo, Alice; Matende, Ibrahim; Baba, Samson; Reacher, Mark; Matthews, Fiona; Brayne, Carol; Emerson, Paul M

2006-01-01

8

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

PubMed Central

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

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

2006-01-01

9

31 CFR 538.320 - Specified Areas of Sudan.  

Code of Federal Regulations, 2010 CFR

...of Sudan. (a) The term Specified Areas of Sudan means Southern Sudan, Southern Kordofan/Nuba Mountains State, Blue Nile State, Abyei, Darfur, and marginalized areas in and around Khartoum. (b) The term marginalized areas in and around...

2010-07-01

10

Wetland change detection in Nile swamps of southern Sudan using multitemporal satellite imagery  

NASA Astrophysics Data System (ADS)

In this study, the maximum likelihood supervised classification and the post-classification comparison change detection are applied in order to monitor the wetlands by assessing and quantifying the wetland cover changes in the Nile swamps of southern Sudan, called the Sudd, by using the ERDAS IMAGINE software. Three multispectral satellite imageries, acquired in the wet season from 1986 to 2006 by Landsat TM and Landsat ETM+ images, are classified into five main land cover classes namely water, vegetation, urban, wetland-vegetation, and wetland-no vegetation, by using the maximum likelihood supervised classification. A pixel-by-pixel comparison was then performed over the classified thematic map images. The post-classification change detection results show a 3.69% decrease in the wetland-vegetation areas and a 2.68% decrease in the wetland-no vegetation areas within the period 1986 to 1999. In addition, a noticeable increase is observed in the wetland-vegetation areas within the period 1999 to 2006 in the Sudd area as 14.95% of the land cover classes' areas, excluding the wetland-vegetation areas are changed into wetland-vegetation areas while there was a decrease of 5.18% in the wetland-no vegetation areas within the period 1999 to 2006. The objective of this paper is to introduce precedence in studying the wetland cover changes over the Sudd area which can help the output planners develop water resources management projects leading to enhance the life conditions in the Sudd region.

Soliman, Ghada; Soussa, Hoda

2011-01-01

11

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

PubMed Central

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

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

1983-01-01

12

Contesting Miss South Sudan  

Microsoft Academic Search

As South Sudan prepares for a referendum on independence in 2011, heightened nationalist expression within popular and political discourse reveals a messier and more openly disputed conception of the ideal Southern Sudanese woman. In this article I examine one site for debate in the diaspora, the US based Miss South Sudan beauty pageant. Highlighting the perseverance and power of the

Caroline Faria

2010-01-01

13

Gendered citizenship in Sudan: competing debates on family laws among northern and southern elites in Khartoum  

Microsoft Academic Search

In Sudan, family laws are formed and applied by the religious communities – Islamic, Christian and traditional African beliefs –creating a gendered citizenship that has led to the absence of ‘equality before the law’ not only between men and women in general but also between Sudanese women across religious and tribal affiliations. In contrast to the general literature on women's

Liv Tønnessen

2008-01-01

14

Post-conflict mental health needs: a cross-sectional survey of trauma, depression and associated factors in Juba, Southern Sudan  

PubMed Central

Background The signing of the Comprehensive Peace Agreement in January 2005 marked the end of the civil conflict in Sudan lasting over 20 years. The conflict was characterised by widespread violence and large-scale forced migration. Mental health is recognised as a key public health issue for conflict-affected populations. Studies revealed high levels of post-traumatic stress disorder (PTSD) amongst populations from Southern Sudan during the conflict. However, no studies have been conducted on mental health in post-war Southern Sudan. The objective of this study was to measure PTSD and depression in the population in the town of Juba in Southern Sudan; and to investigate the association ofdemographic, displacement, and past and recent trauma exposure variables, on the outcomes of PTSD and depression. Methods A cross-sectional, random cluster survey with a sample of 1242 adults (aged over 18 years) was conducted in November 2007 in the town of Juba, the capital of Southern Sudan. Levels of exposure to traumatic events and PTSD were measured using the Harvard Trauma Questionnaire (original version), and levels of depression measured using the Hopkins Symptom Checklist-25. Multivariate logistic regression was used to analyse the association ofdemographic, displacement and trauma exposure variables on the outcomes of PTSD and depression. Multivariate logistic regression was also conducted to investigate which demographic and displacement variables were associated with exposure to traumatic events. Results Over one third (36%) of respondents met symptom criteria for PTSD and half (50%) of respondents met symptom criteria for depression. The multivariate logistic regression analysis showed strong associations of gender, marital status, forced displacement, and trauma exposure with outcomes of PTSD and depression. Men, IDPs, and refugees and persons displaced more than once were all significantly more likely to have experienced eight or more traumatic events. Conclusion This study provides evidence of high levels of mental distress in the population of Juba Town, and associated risk-factors. Comprehensive social and psychological assistance is urgently required in Juba. PMID:19261192

Roberts, Bayard; Damundu, Eliaba Yona; Lomoro, Olivia; Sondorp, Egbert

2009-01-01

15

Visceral Leishmaniasis Relapse in Southern Sudan (1999–2007): A Retrospective Study of Risk Factors and Trends  

PubMed Central

Background Risk factors associated with L. donovani visceral leishmaniasis (VL; kala azar) relapse are poorly characterized. Methods We investigated patient characteristics and drug regimens associated with VL relapse using data from Médecins Sans Frontières - Holland (MSF) treatment centres in Southern Sudan. We used MSF operational data to investigate trends in VL relapse and associated risk factors. Results We obtained data for 8,800 primary VL and 621 relapse VL patients treated between 1999 and 2007. Records of previous treatment for 166 VL relapse patients (26.7%) were compared with 7,924 primary VL patients who had no record of subsequent relapse. Primary VL patients who relapsed had larger spleens on admission (Hackett grade ?3 vs0, odds ratio (OR) for relapse?=?3.62 (95% CI 1.08, 12.12)) and on discharge (Hackett grade ?3 vs 0, OR?=?5.50 (1.84, 16.49)). Age, sex, malnutrition, mobility, and complications of treatment were not associated with risk of relapse, nor was there any trend over time. Treatment with 17-day sodium stibogluconate/paromomycin (SSG/PM) combination therapy vs 30-day SSG monotherapy was associated with increased risk of relapse (OR?=?2.08 (1.21, 3.58)) but reduced risk of death (OR?=?0.27 (0.20, 0.37)), although these estimates are likely to be residually confounded. MSF operational data showed a crude upward trend in the proportion of VL relapse patients (annual percentage change (APC)?=?11.4% (?3.4%, 28.5%)) and a downward trend in deaths (APC?=??18.1% (?22.5%, ?13.4%)). Conclusions Splenomegaly and 17-day SSG/PM vs 30-day SSG were associated with increased risk of VL relapse. The crude upward trend in VL relapses in Southern Sudan may be attributable to improved access to treatment and reduced mortality due to SSG/PM combination therapy. PMID:20544032

Gorski, Stanislaw; Collin, Simon M.; Ritmeijer, Koert; Keus, Kees; Gatluak, Francis; Mueller, Marius; Davidson, Robert N.

2010-01-01

16

Implications of renewable energy for women in Sudan: challenges and opportunities  

Microsoft Academic Search

In Sudan, electricity reaches only about 30% of the population, mainly in urban areas. Hence, a major problem for rural people is the inadequate supply of power for lighting, heating, cooking, cooling, water pumping, radio or TV communications and security services. Petroleum product supplies, including diesel, kerosene and liquid petroleum gas are irregular and often subject to sudden price increases.

Abdeen Mustafa Omer

2003-01-01

17

Landscape wildfire interactions in Southern Europe: implications for landscape management.  

E-print Network

Landscape ­ wildfire interactions in Southern Europe: implications for landscape management) Landscape ­ wildfire interactions in Southern Europe: implications for landscape management, Journal - p. 2402" #12;Abstract Every year approx. half a million hectares of land are burned by wildfires

Boyer, Edmond

18

Sudan Grass.  

E-print Network

.3~1'1 TEXAS AGRICULTURAL EXPERIMENT STATION BULLETIN No. 172 JANUARY, 1915 ? SUDAN GRASS ? '! POSTOFFICE: COLLEGE STATION, BRAZOS COUNTY, TEXAS ? VON BOECKMANN-JONES CO., PRINTERS, AUSTIN, TEXAS 1915 BLANK PAGE IN ORIGINAL A42-f1 5-30m... TEXAS AGRICULTURAL EXPERIMENT~ STATION BuLLETIN No. 172 JANUARY, 1915 SUDAN GRASS BY B. YOUNGBLOOD .AND A. B. CONNER POSTOFFICE: COLLI:GE STATION, BRAZOS COUNTY, TEXAS VON BOECKMANN-JONES CO., PRINTERS, .\\. USTIN .. I'EXAS 1915 AGRICULTURAL...

Youngblood, B.; Conner, A. B.

1915-01-01

19

DEM-optical-radar data integration for palaeohydrological mapping in the northern Darfur, Sudan: implication for groundwater exploration  

Microsoft Academic Search

North?western Sudan, as a part of the eastern Sahara, is among the driest places on earth. However, the region underwent drastic climatic changes through the alternation of dry and wet conditions in the past. During humid phases, when the rain was plentiful over a prolonged time period, the surface was veined by rivers and dotted by large lakes. The new

E. Ghoneim; F. El-Baz

2007-01-01

20

Spectral P-wave magnitudes, magnitude spectra and other source parameters for the 1990 southern Sudan and the 2005 Lake Tanganyika earthquakes  

NASA Astrophysics Data System (ADS)

Teleseismic Broadband seismograms of P-waves from the May 1990 southern Sudan and the December, 2005 Lake Tanganyika earthquakes; the western branch of the East African Rift System at different azimuths have been investigated on the basis of magnitude spectra. The two earthquakes are the largest shocks in the East African Rift System and its extension in southern Sudan. Focal mechanism solutions along with geological evidences suggest that the first event represents a complex style of the deformation at the intersection of the northern branch of the western branch of the East African Rift and Aswa Shear Zone while the second one represents the current tensional stress on the East African Rift. The maximum average spectral magnitude for the first event is determined to be 6.79 at 4 s period compared to 6.33 at 4 s period for the second event. The other source parameters for the two earthquakes were also estimated. The first event had a seismic moment over fourth that of the second one. The two events are radiated from patches of faults having radii of 13.05 and 7.85 km, respectively. The average displacement and stress drop are estimated to be 0.56 m and 1.65 MPa for the first event and 0.43 m and 2.20 MPa for the second one. The source parameters that describe inhomogeneity of the fault are also determined from the magnitude spectra. These additional parameters are complexity, asperity radius, displacements across the asperity and ambient stress drop. Both events produce moderate rupture complexity. Compared to the second event, the first event is characterized by relatively higher complexity, a low average stress drop and a high ambient stress. A reasonable explanation for the variations in these parameters may suggest variation in the strength of the seismogenic fault which provides the relations between the different source parameters. The values of stress drops and the ambient stresses estimated for both events indicate that these earthquakes are of interplate type.

Moussa, Hesham Hussein Mohamed

2008-10-01

21

Seismotectonic implications of sand blows in the southern Mississippi Embayment  

Microsoft Academic Search

We explore seismically-induced sand blows from the southern Mississippi Embayment and their implications in resolving the question of near or distal epicentral source region. This was accomplished using aerial photography, field excavations, and cone penetration tests. Our analysis shows that three sand blow fields exhibit a distinct chronology of strong ground motion for the southern embayment: (1) The Ashley County,

R. T. Cox; A. A. Hill; D. Larsen; T. Holzer; S. L Forman; T. Noce; C. Gardner; J. Morat

2007-01-01

22

Al Jazirah, Sudan  

NASA Technical Reports Server (NTRS)

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.

2008-01-01

23

A climate trend analysis of Sudan  

USGS Publications Warehouse

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.

Funk, Chris; Eilerts, Gary; Verdin, Jim; Rowland, Jim; Marshall, Michael

2011-01-01

24

Energy in Sudan  

Microsoft Academic Search

Sudan is an agricultural country with fertile land, plenty of water resources, livestock, forestry resources, and agricultural residues. An overview of the energy situation in Sudan is introduced with reference to the end uses and regional distribution. Energy sources are divided into two main types: conventional energy (biomass, petroleum products, and electricity); and non-conventional energy (solar, wind, hydro, etc.). Sudan

Abdeen Mustafa Omer

2003-01-01

25

A regional reconnaissance on yellow fever in the Sudan  

PubMed Central

Neutralization-tests with yellow fever virus performed on 666 human sera collected in the southern Sudan imply that yellow fever is still endemic south of the 10th parallel, in the south-west border of the Nuba Mountains, and in the plains west of the Nuba Mountains as far north as El Muglad. Similar tests on bloods from 110 primates revealed a high rate of immunity among both baboons (Papio sp.) (94%) and grivet monkeys (Cercopithecus aethiops) (77%), and a very low rate (1 in 56) among galagos (Galago senegalensis). It would therefore appear that, in contrast to the baboon and the grivet monkey, the galago is not significantly involved in the cycle of the virus. The epidemiological implications of these findings are discussed. PMID:14379007

Taylor, R. M.; Haseeb, M. A.; Work, T. H.

1955-01-01

26

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)

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.

Lavie, Emilie; Robert, Elodie

2013-04-01

27

Aquatic and terrestrial invertebrate drift in southern Appalachian Mountain streams: implications for trout  

E-print Network

Aquatic and terrestrial invertebrate drift in southern Appalachian Mountain streams: implications invertebrate drift in six south-western North Carolina streams and their implications for trout production productivity. However, little is known about the contribution of terrestrial invertebrates entering drift

Hutchens, John

28

76 FR 63629 - Designation of Republic of South Sudan for Temporary Protected Status  

Federal Register 2010, 2011, 2012, 2013, 2014

...Violence has increased in South Kordofan. In June 2011...artillery shelling in the eastern and southern parts of...access to drinking water. South Sudan census results...drought in the Horn of Africa. As of July 21, 2011...has not yet affected South Sudan directly,...

2011-10-13

29

Biogas energy technology in Sudan  

Microsoft Academic Search

Biogas from biomass appears to have potential as an alternative energy in Sudan, which is potentially rich in biomass resources. This is an overview of some salient points and perspectives of biogas technology in Sudan. The current literature is reviewed regarding the ecological, social, cultural and economic impacts of biogas technology. Sudan is blessed with abundant solar, wind, hydro, and

A. M. Omer; Y. Fadalla

2003-01-01

30

Seismotectonic implications of sand blows in the southern Mississippi Embayment  

USGS Publications Warehouse

We explore seismically-induced sand blows from the southern Mississippi Embayment and their implications in resolving the question of near or distal epicentral source region. This was accomplished using aerial photography, field excavations, and cone penetration tests. Our analysis shows that three sand blow fields exhibit a distinct chronology of strong ground motion for the southern embayment: (1) The Ashley County, Arkansas sand blow field, near the Arkansas/Louisiana state border, experienced four Holocene sand venting episodes; (2) to the north, the Desha County field experienced at least three episodes of liquefaction; and (3) the Lincoln-Jefferson Counties field experienced at least one episode. Cone penetration tests (CPT) conducted in and between the sand blow fields suggest that the fields may not be distal liquefaction associated with New Madrid seismic zone earthquakes but rather are likely associated with strong earthquakes on local faults. This conclusion is consistent with the differences in timing of the southern embayment sand venting episodes and those in the New Madrid seismic zone. These results suggest that active tectonism and strong seismicity in intraplate North America may not be localized at isolated weak spots, but rather widespread on fault systems that are favorably oriented for slip in the contemporary stress field. ?? 2006 Elsevier B.V. All rights reserved.

Cox, R.T.; Hill, A.A.; Larsen, D.; Holzer, T.; Forman, S.L.; Noce, T.; Gardner, C.; Morat, J.

2007-01-01

31

UNICEF and the Sudan.  

ERIC Educational Resources Information Center

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…

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

32

Demanding Divestment from Sudan  

ERIC Educational Resources Information Center

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…

Asquith, Christina

2006-01-01

33

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

Microsoft Academic Search

BackgroundLarge 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 FindingsThe survey area was defined as one domain of eight counties in Unity State. Across

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

2012-01-01

34

Dust storm in Sudan  

NASA Technical Reports Server (NTRS)

A dust storm is carrying dust from Sudan, Africa, out over the Red Sea (right) in this Moderate Resolution Imaging Spectroradiometer Image from June 30, 2002. In the lower left quadrant of the image, the sinuous path of the Nile can be seen. Dust storms such as this reduce the amount of solar radiation that reaches the surface, and have a cooling effect on the area. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

2002-01-01

35

Famine in Sudan  

NSDL National Science Digital Library

This week's In the News covers the famine in Sudan. The seven resources discussed offer news, analysis, and commentary. The largest country in Africa, Sudan has been wracked by civil strife and violence since becoming an independent republic in 1956. Years of civil war have devastated the Sudanese economy and society, killing over 1.2 million since 1983 alone. Despite this tortured history, Sudan may now be facing its worst crisis. After two years of drought, bad harvests and renewed fighting, over 2.5 million people require emergency food aid and malnutrition rates exceed 60% of the population in some areas. While international relief agencies have scrambled to assist, many estimate that only about half of what is needed in terms of money and material is arriving. While the weather has played a role in the current crisis, it is also a product of the long-running conflict between the Islamic government in the north and the mainly Christian south. An attempt to institute strict Islamic law in the south in 1983 touched off a conflict between the government and numerous rebel groups in the south, most importantly the Sudan's Peoples Liberation Army (SPLA), which became a full-scale civil war by the mid-1980s. Since then some concessions have been made to the South and several peace talks were held. The present situation was touched off in February, 1998 when local warlord Kerubino Kuanyin Bol, who had been fighting for the government, rejoined the rebellion, reigniting the conflict. Two weeks ago the government and the SPLA announced a one-month cease-fire to allow aid to get through, but many aid workers believe it may be too late. The rainy season has finally arrived, one moth late, hampering communication and the transportation of much-needed food and medicine. In the meantime, Sudan has rapidly become a destination of choice for documentary news photographers eager for startling and powerful photos. Whether or not sufficient aid will arrive in their wake remains to be seen.

de Nie, Michael Willem.

1998-01-01

36

Structural Implications of Walloomsac and Hartland Rocks of Southern Manhattan Island  

E-print Network

Structural Implications of Walloomsac and Hartland Rocks of Southern Manhattan Island Charles reappears across town near the Brooklyn Bridge. The duplication of Walloomsac rocks on either side in the subsurface of southern Manhattan. To Cite This Abstract: Merguerian, Charles; and Moss, C. J., 2006b

Merguerian, Charles

37

As an eye witness to the celebrated independence of South Sudan, how  

E-print Network

or secession. Southern Sudanese recorded a massive vote for secession from the north in the January 9, 2011 of violence erupting due to political tension between the northern and southern governments and militias who split from the SPLM (Sudan Liberation Movement) prior to secession. I was in direct contact with many

Edwards, Paul N.

38

Geodynamic implications of earthquake data in the southern Tyrrhenian sea  

Microsoft Academic Search

Data from short-period seismic stations operating in Calabria, Sicily and the Aeolian Islands have been used to investigate earthquake properties of the southern Tyrrhenian lithosphere. The results have been analyzed, taking into account other geophysical and geological information available in the literature for the same region, with the main purpose of contributing to the definition of local geodynamic processes.Space distribution

G. Neri; D. Caccamo; O. Cocina; A. Montalto

1996-01-01

39

Seismic Hazard Implication of the Seismotectonics of southern Africa  

NASA Astrophysics Data System (ADS)

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.

Midzi, Vunganai; Mulabisana, Thifelimbilu; Manzunzu, Brassnavy

2014-05-01

40

A Southern Hemisphere Wave Response to ENSO with Implications for Southern Africa Precipitation.  

NASA Astrophysics Data System (ADS)

Ensemble GCM simulations with an imposed, idealized warming of the eastern Pacific Ocean reveal two wave anomalies in the Southern Hemisphere, one in the eastern and one in the western hemisphere. Both are statistically significant at the 99% confidence level. Application of a steady-state linear model and a Rossby wave source analysis is used to diagnose the causes of the waves. The western hemisphere wave is forced by the advection and stretching of planetary vorticity by the divergent flow from the Southern Hemisphere component of the central Pacific `twin anticyclones' that straddle the equator during warm events. The eastern hemisphere wave is a result of the northeastward shift of the South Indian convergence zone (SICZ) that, in turn, is forced from the upper troposphere by convergence to the north. An upper-level convergence maximum over the equatorial Indian Ocean induces divergence to the south, encouraging vertical motion and precipitation to the northeast of the SICZ's normal position. The resulting anomalous upper-level convergence in the climatological position of the SICZ, as well as the anomalous vorticity flux convergence by the transients associated with an equatorward shift of the storm track behind the SICZ, force the eastern hemisphere Rossby wave.Since a shift of the SICZ is a fairly robust observed consequence of ENSO events, these results suggest the mechanism by which drought conditions develop over southern Africa at the height of many warm events. Seasonal prediction capabilities in this region can be improved by monitoring and understanding the details and consequences of the adjustment of the Walker circulation near the equator outside of the Pacific Ocean basin.

Cook, Kerry H.

2001-08-01

41

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

Microsoft Academic Search

The El Niño Southern Oscillation (ENSO) significantly influences marine ecosystems and the sustained exploitation of marine\\u000a resources in the coastal zone of the Humboldt Current upwelling system. Both its warm (El Niño: EN) and cold (La Niña: LN)\\u000a phase have drastic implications for the ecology, socio-economy and infrastructure along most of Pacific South America. Local\\u000a artisanal fisheries, which especially suffer

Sven Thatje; Olaf Heilmayer; Jürgen Laudien

2008-01-01

42

Current situation of tropical theileriosis in the Sudan.  

PubMed

Tropical theileriosis has long been recognized as a hindrance to the development of sound dairy industry in the Sudan and is a cause of major economic losses. Serological surveys indicated that Theileria annulata infection is widespread in the country but the disease mostly affects exotic dairy breeds and their crosses with indigenous breeds. The disease has recently been identified in Darfur and southern parts of Blue Nile State in dairy farms around large urban areas where it has never been detected before. These new introductions were accompanied by the establishment of Hyalomma anatolicum tick which is the main vector of the parasite in the Sudan. The disease is routinely diagnosed using microscopic examination of stained blood and lymph node biopsy smears. More advanced techniques are mainly used for research purposes. Tropical theileriosis in the Sudan is mainly controlled by using anti-theilerial drugs and acaricide application. It is recommended that live attenuated schizont vaccines developed from locally isolated T. annulata strains be used to control the disease. In addition, every care should be taken to prevent introduction of the disease into new areas. PMID:22565402

El Hussein, Abdelrahim M; Hassan, Shawgi M; Salih, Diaeldin A

2012-08-01

43

Nile River, Khartoum, Sudan, Africa  

NASA Technical Reports Server (NTRS)

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.

1983-01-01

44

Agricultural fields, Khartoum, Sudan, Africa  

NASA Technical Reports Server (NTRS)

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.

1992-01-01

45

GURUSWAMI, H ASTAD, SUDAN, AND ZUCKERMAN 1  

E-print Network

GURUSWAMI, H š ASTAD, SUDAN, AND ZUCKERMAN 1 Combinatorial Bounds for List Decoding Venkatesan Guruswami Johan Hšastad Madhu Sudan David Zuckerman Abstract--- Informally, an error­correcting code has Zuckerman's address is Department of Computer Science, University of Texas, Austin, TX 78712, USA. Email

HÃ¥stad, Johan

46

GURUSWAMI, H ASTAD, SUDAN, AND ZUCKERMAN 1  

E-print Network

GURUSWAMI, H š ASTAD, SUDAN, AND ZUCKERMAN 1 Combinatorial Bounds for List Decoding Venkatesan Guruswami Johan Hšastad Madhu Sudan David Zuckerman Abstract--- Informally, an error­correcting code has, and NTT Award MIT2001­04. David Zuckerman's address is Department of Computer Science, University of Texas

Guruswami, Venkatesan

47

Rift Valley Fever, Sudan, 2007 and 2010  

PubMed Central

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

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

48

UNDP supports HIV / AIDS / STD project for war-torn south Sudan -- a special report.  

PubMed

This article describes a UN HIV/AIDS and sexually transmitted disease (STD) project in war-torn south Sudan. The 3-year project relies on collaboration between adversaries and implementation in government-held and rebel-controlled areas. The project aims to reduce the risk and vulnerability to HIV/AIDS/STDs and to foster dialogue among adversaries as a means of conflict resolution. The World Health Organization will contribute technical assistance. Local partners including the government, the Southern Sudan Independence Movement, and the Sudanese People's Liberation Movement will contribute resources valued at about $100,000. The total UN contribution is about $300,000. HIV transmission has increased due to a high concentration of military personnel and population displacement. Available information suggests that the south has the highest HIV prevalence and 46% of known AIDS cases. STDs increased from 2.3% in 1989 to 14.1% in 1994. The project focuses on women, youth, and other vulnerable groups. The project is in its 9-month preparatory phase. The preparatory phase includes analysis of the HIV/AIDS/STD situation, design of a sustainable program, assessment of causative factors, and establishment of a mechanism for effectively coordinating the project. The civil war will affect priorities, strategies, and activities. In government-controlled areas, the Sudan National AIDS program will conduct activities. In non-government areas, the Sudan Rehabilitation and Relief Association, the Relief Association for South Sudan, and health and humanitarian authorities of the liberation groups will conduct programs. The UN Office of Special Projects will provide oversight during the preparatory phase. Sudan's UN Country Theme Group on HIV/AIDS will be the coordinating group. PMID:12348210

Del Viso, N

1997-01-01

49

Sudan Grass for Hay, Seed and Pasture.  

E-print Network

TEXAS AGRICULTURAL EXPERIMENT STATION A. B. CONNER, DIRECTOR COLLEGE STATION. BRAZOS COUNTY. TEXAS DMSION OF AGRONOMY SUDAN GRASS FOR HAY, SEED, AND PASTURE AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS T. 0. WALTON. President ADMINISTRATION... with the School of Agriculture. Sudan grass is an annual grass sorghum introduced into this country in 1909 by the United States Department of Agriculture. It was grown at Chillicothe that year and thereafter the seed were widely distributed to farmers over...

Quinby, John Roy; Jones, D. L. (Don L.); Karper, R. E. (Robert Earl)

1929-01-01

50

A Late Neoproterozoic (V630 Ma) high-magnesium andesite suite from southern Israel: implications for the consolidation  

E-print Network

A Late Neoproterozoic (V630 Ma) high-magnesium andesite suite from southern Israel: implications, when the dykes were emplaced. These magmas had compositions of basaltic andesites and andesites but had and depleted in heavy rare earth elements. They are high-magnesium andesites and are similar to low-Ca type 2

Basu, Asish R.

51

Measurements of air-sea gas exchange at high wind speeds in the Southern Ocean: Implications for global parameterizations  

E-print Network

Measurements of air-sea gas exchange at high wind speeds in the Southern Ocean: Implications August 2006. [1] The SOLAS Air-Sea Gas Exchange (SAGE) Experiment was conducted in the western Pacific that factors controlling air-sea gas exchange in this region are similar to those in other parts of the world

Ho, David

52

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

E-print Network

The Discovery of New Deep-Sea Hydrothermal Vent Communities in the Southern Ocean and Implications discovery of deep-sea hydrothermal vents along the Gala´pagos Rift in 1977, numerous vent sites and endemic deep-sea fauna. It has also been proposed as a gateway connecting hydrothermal vents in different

Naveira Garabato, Alberto

53

Environmental justice and regional inequality in southern California: implications for future research.  

PubMed Central

Environmental justice offers researchers new insights into the juncture of social inequality and public health and provides a framework for policy discussions on the impact of discrimination on the environmental health of diverse communities in the United States. Yet, causally linking the presence of potentially hazardous facilities or environmental pollution with adverse health effects is difficult, particularly in situations in which diverse populations are exposed to complex chemical mixtures. A community-academic research collaborative in southern California sought to address some of these methodological challenges by conducting environmental justice research that makes use of recent advances in air emissions inventories and air exposure modeling data. Results from several of our studies indicate that communities of color bear a disproportionate burden in the location of treatment, storage, and disposal facilities and Toxic Release Inventory facilities. Longitudinal analysis further suggests that facility siting in communities of color, not market-based "minority move-in," accounts for these disparities. The collaborative also investigated the health risk implications of outdoor air toxics exposures from mobile and stationary sources and found that race plays an explanatory role in predicting cancer risk distributions among populations in the region, even after controlling for other socioeconomic and demographic indicators. Although it is unclear whether study results from southern California can be meaningfully generalized to other regions in the United States, they do have implications for approaching future research in the realm of environmental justice. The authors propose a political economy and social inequality framework to guide future research that could better elucidate the origins of environmental inequality and reasons for its persistence. PMID:11929723

Morello-Frosch, Rachel; Pastor, Manuel; Porras, Carlos; Sadd, James

2002-01-01

54

The majority legal status of women in southern Africa: implications for women and families.  

PubMed

The introduction to this article, which provides an overview of the legal status of women in southern Africa, notes that the legal majority status of women is an important social policy issue with broad implications for the socioeconomic welfare of women and their families. The dual legal system (general law and customary law) which arose from colonization is a complicating factor in the legal life of women in the region. The colonial legal system legitimized the subordination of women, and during the colonial period the customary system was reinvented to the detriment of women by male African leaders working in collusion with colonial authorities. The next section of this article presents a brief description of the legal standing of women in terms of majority/minority status, marriage arrangements, and right to own immovable property in the states of Botswana, Lesotho, South Africa, Swaziland, Zambia, and Zimbabwe. The implications of the majority/minority status of women are then explored through consideration of the economic effects of majority rights, of family relationships, and of efforts to change the legal system (by changing the content and implementation of laws and by empowering women to take advantage of their rights). The barriers that impede women from asserting their rights point to the need for removal of broad-based economic, educational, and cultural constraints. Granting majority rights is an important step toward the goals of eliminating poverty and ending the marginalization of women. PMID:12320840

Van Hook, M P; Ngwenya, B N

1996-01-01

55

Biomass energy potential and future prospect in Sudan  

Microsoft Academic Search

Sudan is an agricultural country with fertile land, plenty of water resources, livestock, forestry resources, and agricultural residues. Sudan is an energy importing country and the energy requirements have been supplied through imports that have caused financial problems. Because of the economical problems in Sudan today, the Sudanese energy policy should be concentrated on assurance of energy supply, reliability, domestic

Abdeen M. Omer

2005-01-01

56

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

57

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

NASA Astrophysics Data System (ADS)

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.

Thatje, Sven; Heilmayer, Olaf; Laudien, Jürgen

2008-03-01

58

The ethnic distribution of sickle cell disease in Sudan  

PubMed Central

Sickle cell disease (SCD) is one of the most common inherited disorders of haemoglobin in Africa and it is expected that sickle cell trait varies in frequency in different areas in Sudan. An extensive literature search was carried out accessing the US National Library of Medicine, the WHO Eastern Mediterranean Region resources, the Catalogue for Transmission Genetics in Arabs and papers and documents published in Sudan that included data on the prevalence of sickle cell anaemia and trait. Rates of SCA and trait varied in different areas in Sudan with the highest rates reported from Western and Eastern Sudan where one in every 123 children born in Messeryia tribe in Western Sudan is at risk of having SCD. High consanguinity rates and malaria endemicity are strong related factors with sickle cell gene in Sudan. This review will present what is known about the rates of sickle cell gene in different ethnic groups in Sudan. PMID:25360197

Sabahelzain, Majdi Mohammed; Hamamy, Hanan

2014-01-01

59

The ethnic distribution of sickle cell disease in Sudan.  

PubMed

Sickle cell disease (SCD) is one of the most common inherited disorders of haemoglobin in Africa and it is expected that sickle cell trait varies in frequency in different areas in Sudan. An extensive literature search was carried out accessing the US National Library of Medicine, the WHO Eastern Mediterranean Region resources, the Catalogue for Transmission Genetics in Arabs and papers and documents published in Sudan that included data on the prevalence of sickle cell anaemia and trait. Rates of SCA and trait varied in different areas in Sudan with the highest rates reported from Western and Eastern Sudan where one in every 123 children born in Messeryia tribe in Western Sudan is at risk of having SCD. High consanguinity rates and malaria endemicity are strong related factors with sickle cell gene in Sudan. This review will present what is known about the rates of sickle cell gene in different ethnic groups in Sudan. PMID:25360197

Sabahelzain, Majdi Mohammed; Hamamy, Hanan

2014-01-01

60

Mesozoic break-up of SW Gondwana: implications for regional hydrocarbon potential of the southern South Atlantic  

Microsoft Academic Search

This work provides new palinspastic palaeofacies reconstructions of SW Gondwana incorporating rotation of a Falkland\\/Malvinas microplate. We discuss the implications of this for the tectonic evolution of the southern South Atlantic and hence for the regional hydrocarbon potential.Existing Gondwana reconstructions display good fits of major continents but poorly constrained fits of microcontinents. In most continental reconstructions, the Falkland\\/Malvinas Plateau was

David Macdonald; Irene Gomez-Perez; Juan Franzese; Luis Spalletti; Lawrence Lawver; Lisa Gahagan; Ian Dalziel; Chris Thomas; Nigel Trewin; Malcolm Hole; Douglas Paton

2003-01-01

61

Ebola haemorrhagic fever in Sudan, 1976  

PubMed Central

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

1978-01-01

62

Declining sand dune activity in the southern Canadian prairies: Historical context, controls and ecosystem implications  

NASA Astrophysics Data System (ADS)

Sandhills are islands of biodiversity in the southern Canadian prairies that sustain habitat for many rare and endangered species. These unique areas consist of large expanses of dune fields now mostly stabilized by grassland vegetation. Historically, the number of active dunes has decreased significantly due to vegetation stabilization, resulting in a dramatic decline of open-sand habitat for a variety of dune-dependent species. Without a certain level of wind erosion, opportunities for establishment of early-stage, species-rich vegetation types are diminished and open-sand habitat decreases by encroachment of the surrounding grassland vegetation. The current trend of dune stabilization, however, implies that wind erosion is decreasing, thereby threatening the continued existence of a variety of dune-dependent plants, arthropods and vertebrates, as well as other less-specialized species that benefit indirectly from these habitats. By reviewing factors contributing to the historical decline of active dunes, as well as the ecological implications of dune stabilization, the aim of this paper is to establish the biophysical context for new land management strategies that conserve valued landscape components, such as active dunes, and the processes therein. As dune stabilization continues management interventions will be required to sustain or re-establish open sand and the species that rely on these habitats.

Hugenholtz, Chris H.; Bender, Darren; Wolfe, Stephen A.

2010-11-01

63

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

PubMed Central

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

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

2014-01-01

64

Rethinking the civil war in Sudan  

Microsoft Academic Search

A troubled country, the largest in a troubled continent, the Sudan surely tells one of the most tragic stories of war. The war is presented in the West as a religiously inspired persecution of Christian tribesmen in the south by the Islamic Fundamentalist government. The real story, however, is one of continued opposition and periodic fighting since shortly before independence

Roger Dean

2000-01-01

65

Paleoseismology of the southern Panamint Valley fault: Implications for regional earthquake occurrence and seismic hazard in southern California  

NASA Astrophysics Data System (ADS)

data from the southern Panamint Valley fault (PVF) reveal evidence of at least four surface ruptures during late Holocene time (0.33-0.48 ka, 0.9-3.0 ka, 3.3-3.6 ka, and >4.1 ka). These paleo-earthquake ages indicate that the southern PVF has ruptured at least once and possibly twice during the ongoing (?1.5 ka) seismic cluster in the Mojave section of the eastern California shear zone (ECSZ). The most recent event (MRE) on the PVF is also similar in age to the 1872 Owens Valley earthquake and the geomorphically youthful MRE on the Death Valley fault. The timing of the three oldest events at our site shows that the PVF ruptured at least once and possibly thrice during the well-defined 2-5 ka seismic lull in the Mojave section of the ECSZ. Interestingly, the 3.3-3.6 ka age of Event 3 overlaps with the 3.3-3.8 ka age of the penultimate (i.e., pre-1872) rupture on the central Owens Valley fault. These new PVF data support the notion that earthquake occurrence in the ECSZ may be spatially and temporally complex, with earthquake clusters occurring in different regions at different times. Coulomb failure function modeling of the Panamint Valley and Garlock faults reveals significant stress interactions between these two faults that may influence future earthquake occurrence. Specifically, our models suggest a possible rupture sequence whereby an event on the southern Panamint Valley fault can lead to the potential triggering of an event on the Garlock fault, which in turn could trigger the Mojave section of the San Andreas Fault.

McAuliffe, Lee J.; Dolan, James F.; Kirby, Eric; Rollins, Chris; Haravitch, Ben; Alm, Steve; Rittenour, Tammy M.

2013-09-01

66

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

PubMed

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

Robinson, Sharon A; Erickson, David J

2015-02-01

67

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

PubMed Central

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

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

1979-01-01

68

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

PubMed Central

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

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

1998-01-01

69

Retrospective measles outbreak investigation: Sudan, 2004.  

PubMed

Recent population-based studies of measles incidence and deaths in Sudan are not available. To determine the epidemiology and case-fatality rate (CFR) of measles, we conducted a retrospective outbreak investigation in two states in northern Sudan. Of 1144 case-patients identified, 92% were <15 years; 48.6% were vaccinated; and 62% received vitamin A before illness. Ten measles-associated deaths were identified (CFR 0.9%; 95% confidence interval 0.16-1.91). CFR determined by this investigation is lower than expected for the region but remains 10 times higher than that in developed countries. Measles control should be strengthened by improving vaccine coverage, measles surveillance and case-management. PMID:16735363

Coronado, Fátima; Musa, Nisreen; El Tayeb, El Sayed Ahmed; Haithami, Salah; Dabbagh, Alya; Mahoney, Frank; Nandy, Robin; Cairns, Lisa

2006-10-01

70

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

ERIC Educational Resources Information Center

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.…

Nziramasanga, Caiphas T.

71

Structural development of the southern basin, onshore Trinidad: Implications for hydrocarbon entrapment  

Microsoft Academic Search

Episodic compressional deformation across onshore southern Trinidad formed a complex spectrum of fold timing and fold types. Successful oil traps are not related to a specific time interval of structural formation, a specific oil expulsion event or a specific fold morphology. Traps that retained hydrocarbons may be related to seal facies. The tectono-stratigraphic section of onshore southern Trinidad, south of

L. J. Aden; R. E. Bierley

1996-01-01

72

Salt fortification with iodine: Sudan situation analysis.  

PubMed

Iodine deficiency disorders (IDD) constitute a severe public health problem in Sudan. IDD affects children and women throughout life. More than 2 out of 10 school age children have goiter. The prevalence reaches 40% in some regions of the country. Several interventional measures were introduced to control the IDD problem. While the situation with regard to production and supply of iodized salt was thus deteriorating, an Emergency Food Security and Nutrition Assessment Survey (EFSNA) revealed that the prevalence of IDD among adult women, as reflected in the presence of visible goiter, was as high as 25.5%. We have conducted a situation analysis survey in the Republic of Sudan to review the prevailing situation and suggest a benchmark that would help in developing effective control measures and in monitoring their implementations. SWOT analysis, questionnaire, focus groups discussion beside a combination of rapid assessment approach and qualitative method were used to critically evaluate the salt iodization situation in the country and assess the prevailing IDD situation in and propose a plan of action to overcome the bottlenecks. The survey concluded that Iodine deficiency affects children and women all through Sudan. The prevalence is even greater in some regions of the country and there is no supportive policy environment for successful universal salt iodization. To overcome this aggravated situation Sudan will need to conduct a baseline study to provide data on the prevalence of IDD, geographic distribution, knowledge, attitudes and practices relating to iodine deficiency. This will provide a benchmark that will help in developing effective control measures and in monitoring their implementation. The study recommended a set of actions to the government to overcome the prevailing situation and strengthening the current policy and implementation. PMID:19326717

Izzeldin, S H; Crawford, M A; Ghebremeskel, K

2009-01-01

73

Mapping the potential risk of mycetoma infection in Sudan and South Sudan using ecological niche modeling.  

PubMed

In 2013, the World Health Organization (WHO) recognized mycetoma as one of the neglected tropical conditions due to the efforts of the mycetoma consortium. This same consortium formulated knowledge gaps that require further research. One of these gaps was that very few data are available on the epidemiology and transmission cycle of the causative agents. Previous work suggested a soil-borne or Acacia thorn-prick-mediated origin of mycetoma infections, but no studies have investigated effects of soil type and Acacia geographic distribution on mycetoma case distributions. Here, we map risk of mycetoma infection across Sudan and South Sudan using ecological niche modeling (ENM). For this study, records of mycetoma cases were obtained from the scientific literature and GIDEON; Acacia records were obtained from the Global Biodiversity Information Facility. We developed ENMs based on digital GIS data layers summarizing soil characteristics, land-surface temperature, and greenness indices to provide a rich picture of environmental variation across Sudan and South Sudan. ENMs were calibrated in known endemic districts and transferred countrywide; model results suggested that risk is greatest in an east-west belt across central Sudan. Visualizing ENMs in environmental dimensions, mycetoma occurs under diverse environmental conditions. We compared niches of mycetoma and Acacia trees, and could not reject the null hypothesis of niche similarity. This study revealed contributions of different environmental factors to mycetoma infection risk, identified suitable environments and regions for transmission, signaled a potential mycetoma-Acacia association, and provided steps towards a robust risk map for the disease. PMID:25330098

Samy, Abdallah M; van de Sande, Wendy W J; Fahal, Ahmed Hassan; Peterson, A Townsend

2014-10-01

74

Mapping the Potential Risk of Mycetoma Infection in Sudan and South Sudan Using Ecological Niche Modeling  

PubMed Central

In 2013, the World Health Organization (WHO) recognized mycetoma as one of the neglected tropical conditions due to the efforts of the mycetoma consortium. This same consortium formulated knowledge gaps that require further research. One of these gaps was that very few data are available on the epidemiology and transmission cycle of the causative agents. Previous work suggested a soil-borne or Acacia thorn-prick-mediated origin of mycetoma infections, but no studies have investigated effects of soil type and Acacia geographic distribution on mycetoma case distributions. Here, we map risk of mycetoma infection across Sudan and South Sudan using ecological niche modeling (ENM). For this study, records of mycetoma cases were obtained from the scientific literature and GIDEON; Acacia records were obtained from the Global Biodiversity Information Facility. We developed ENMs based on digital GIS data layers summarizing soil characteristics, land-surface temperature, and greenness indices to provide a rich picture of environmental variation across Sudan and South Sudan. ENMs were calibrated in known endemic districts and transferred countrywide; model results suggested that risk is greatest in an east-west belt across central Sudan. Visualizing ENMs in environmental dimensions, mycetoma occurs under diverse environmental conditions. We compared niches of mycetoma and Acacia trees, and could not reject the null hypothesis of niche similarity. This study revealed contributions of different environmental factors to mycetoma infection risk, identified suitable environments and regions for transmission, signaled a potential mycetoma-Acacia association, and provided steps towards a robust risk map for the disease. PMID:25330098

Samy, Abdallah M.; van de Sande, Wendy W. J.; Fahal, Ahmed Hassan; Peterson, A. Townsend

2014-01-01

75

A Grammar of Northern and Southern Gumuz  

ERIC Educational Resources Information Center

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

Ahland, Colleen Anne

2012-01-01

76

Lagrangian tracing of Sahelian Sudan moisture sources  

NASA Astrophysics Data System (ADS)

Sahelian Sudan, 10° to 16°N, is an arid to semi-arid zone that separates the Saharan to the north and the wet Savannah to the south. The region is characterized by, relatively, limited water resources, and hence has a high dependency on the annual rainfall. According to the latest IPCC report, regions that have such limited water resources are highly vulnerable to the ongoing climate change and variability. Taking into account that the agriculture is the main economical activity, the variability in annual rainfall is of direct soci-economical relevance. Similar to the rest of the African Sahel, the rainy season, June through September, across Sahelian Sudan is connected to the annual march of the Intertropical Convergence Zone (ITCZ). However, there still a limited understanding of the actual sources of moisture that supplies this region with water vapor during the rainy season. Broadly speaking, the Atlantic, the Congo rain forest, the Read Sea and the Indian Ocean are the main potential sources. In this study we use Lagrangian tracing technique to indentify the sources of moisture of Sahelian Sudan and attempt quantifying their contribution to the total annual moisture convergence. For this we utilized output from the Lagrangian trajectory model FLEXPART driven by the meteorological fields from the European Center for Medium range Weather Forecast ERA-interim for period of ten years 2000 to 2009. We trace back, for ten days each mass element to indentify the source region. The models also accounts for precipitation and moisture uptakes through the course of the transport of the air parcel from source to destination. Identifying the sources of moisture is of great importance, and can help in two connected directions. First, identifying sources of moisture will help in understanding the variability and will provide insight about the drought causes and mechanisms. Second, revealing the moisture sources would enhance ongoing efforts in seasonal forecasting.

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

2013-04-01

77

Ecological implications of Laurel Wilt infestation on Everglades Tree Islands, southern Florida  

USGS Publications Warehouse

The spread of the redbay ambrosia beetle and its fungal symbiont has been very rapid, exceeding model predictions (Koch and Smith, 2008); by 2011, laurel wilt disease was found from the southern coastal plain of North Carolina to southern peninsular Florida. The first redbay ambrosia beetle was trapped in Miami-Dade County in March 2010, and laurel wilt disease was discovered in swamp bays in February 2011 and in commercial avocado groves about a year later (Kendra and others, 2013). By 2013, laurel wilt disease was seen in swamp bays throughout the southern Everglades in Everglades National Park, Big Cypress National Preserve, and Water Conservation Areas (WCAs) 3A and 3B (Rodgers and others, 2014).

Snyder, James R.

2014-01-01

78

Dracunculiasis Eradication: And Now, South Sudan  

PubMed Central

This report summarizes the status of the global Dracunculiasis Eradication Program as of the end of 2012. Dracunculiasis (Guinea worm disease) has been eliminated from 17 of 21 countries where it was endemic in 1986, when an estimated 3.5 million cases occurred worldwide. Only 542 cases were reported from four countries in 2012, and 103 villages still had indigenous transmission. Most remaining cases were reported from the new Republic of South Sudan, whereas Chad, Ethiopia, and Mali each reported 10 cases or less. Political instability and insecurity in Mali may become the main obstacles to interrupting dracunculiasis transmission forever. PMID:23843492

Hopkins, Donald R.; Ruiz-Tiben, Ernesto; Weiss, Adam; Withers Jr., P. Craig; Eberhard, Mark L.; Roy, Sharon L.

2013-01-01

79

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

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

80

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

NASA Astrophysics Data System (ADS)

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.

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

2013-08-01

81

Quaternary morphotectonic mapping of the Wadi Araba and implications for the tectonic activity of the southern  

E-print Network

the northward motion of Arabia relative to Sinai at a rate of $5 mm/yr. The southern segment of the fault that accommodates the northward motion of the Arabia plate relative to the Sinai subplate (Figure 1a). Numerous studies aimed to determine the slip rate of this fault based on geological observations over the last $20

Klinger, Yann

82

Sediment geochemistry in lower Spencer Gulf, South Australia: implications for southern bluefin tuna farming  

Microsoft Academic Search

Farming of southern bluefin tuna in South Australia currently contributes to more than 30% of the value of the aquaculture production in Australia. This study investigated the natural sedimentary setting of the area designated for this important industry in coastal waters off Port Lincoln, and explored the links between the natural distribution of sediments and potential environmental effects and risks

M. Fernandes; A. Cheshire; A. Doonan

2006-01-01

83

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

ERIC Educational Resources Information Center

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…

Nabe, Jonathan; Imre, Andrea

2008-01-01

84

Production, attributes and relative value of alpaca fleeces in southern Australia and implications for industry development  

Microsoft Academic Search

An investigation of commercially important alpaca fibre attributes aimed to identify the influence of management and production variables on alpaca fibre and to quantify the relative economic value of fibre production. Fleeces from five farms in southern Australia (n=1100) were measured using midside samples and standard tests and were assigned a relative economic value based on an analysis of market

B. A. McGregor

2006-01-01

85

Morphometric variability in the diatom Fragilariopsis kerguelensis: Implications for Southern Ocean paleoceanography  

NASA Astrophysics Data System (ADS)

Diatoms play a central role in the ecosystem of the Southern Ocean, where they represent the main producers and carriers of organic carbon and dissolved silicon towards the deep ocean. Variability in space and time of the size of the most abundant species ( Fragilariopsis kerguelensis) may directly impact the way this ecosystem functions, and also affect the nutrient balance of the global ocean, as important water masses (e.g. the Antarctic Intermediate Water) get their nutrient signature in this area. We used a biometric approach and analyzed the size variability of F. kerguelensis valves in sixty-four surface sediment samples from the Southern Ocean, in sediment trap samples from a mooring (Site PF3) at the Antarctic Polar Front (APF), and along a nearby piston core (PS1654-2). The average length and valve area of F. kerguelensis displayed a distinct increase in the proximity of the APF, and lower values to the north and south of it, and also changed markedly over seasonal cycles, as diatom blooms and nutrient availability waxe and wane. The last glacial to interglacial transition also witnesses important changes in the general shape and valve size of F. kerguelensis, with specimens from glacial intervals being ca. 30% larger than their interglacial counterparts (195 versus 150 ?m 2 valve area). A sharp peak in average area and a very specific valve morphology correspond to the first signs of deglaciation and concurring SST (Sea Surface Temperature) increase and sea-ice retreat. The latter, together with melting icebergs, may have contributed dissolved iron to surface waters. The highest average sizes during glacial intervals are higher than what found anywhere in the Southern Ocean today. The newly proposed proxy (valve area and shape of F. kerguelensis) may thus prove useful for the reconstruction of the past position and nutrient characteristics of the APF and "opal belt", a region characterized by high production and export of biogenic silica, in a particularly sensitive and dynamic area such as the Southern Ocean.

Cortese, G.; Gersonde, R.

2007-05-01

86

Process-form relationships in Southern Italian badlands: erosion rates and implications for landform evolution  

Microsoft Academic Search

Characteristic badlands are incised into Plio-Pleistocene clays in Basilicata, southern Italy, creating steep, scarp slopes with knife-edge ridges (calanchi) and small dome-shaped forms (biancane). Erosion pin data for the period 1997-2003 give mean annual erosion rates for dome-shaped biancane in the range 9-19 mm a ? ? ? ? ?1 , while rates for the calanchi scarps are lower, at

Michèle L. Clarke; Helen M. Rendell

2006-01-01

87

Three Late Quaternary pollen diagrams from Southern Patagonia and their palaeoecological implications  

Microsoft Academic Search

Diagrams of fossil pollen in three deposits postdating glacial recession of the last ice age provide an account of late-glacial and Holocene vegetation and palaeoclimate in Southern Patagonia. Sites are mires, located along the Estrecho de Magallanes at Punta Arenas (53°09?S, 70°57?W) and Puerto del Hambre (53°36?S, 70°55?W), and an intermittent lake, some 300 km to the north, at Torres

C. J. Heusser

1995-01-01

88

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

89

Evidence for genetic differentiation at the microgeographic scale in Phlebotomus papatasi populations from Sudan  

PubMed Central

Background Cutaneous Leishmaniasis (CL) is endemic in Sudan. It is caused by Leishmania major parasites and transmitted by Phlebotomus papatasi sandflies. Recently, uncommon clinical manifestations of CL have been reported. Moreover, L. donovani parasites that cause Visceral Leishmaniasis (VL) have been isolated from CL lesions of some patients who contracted the disease in Khartoum State, Central Sudan with no history of travelling to VL endemic sites on south-eastern Sudan. Because different clinical manifestations and the parasite behaviour could be related to genetic differentiation, or even sub-structuring within sandfly vector populations, a population genetic study was conducted on P. papatasi populations collected from different localities in Khartoum State known for their uncommon CL cases and characterized by contrasting environmental conditions. Methods A set of seven microsatellite loci was used to investigate the population structure of P. papatasi samples collected from different localities in Khartoum State, Central Sudan. Populations from Kassala State, Eastern Sudan and Egypt were also included in the analyses as outgroups. The level of genetic diversity and genetic differentiation among natural populations of P. papatasi was determined using FST statistics and Bayesian assignments. Results Genetic analyses revealed significant genetic differentiation (FST) between the Sudanese and the Egyptian populations. Within the Sudanese P. papatasi populations, one population from Gerif West, Khartoum State, exhibited significant genetic differentiation from all other populations including those collected as near as 22 km. Conclusion The significant genetic differentiation of Gerif West P. papatasi population from other Sudanese populations may have important implication for the epidemiology of leishmaniasis in Khartoum State and needs to be further investigated. Primarily, it could be linked to the unique location of Gerif West which is confined by the River Nile and its tributaries that may act as a natural barrier for gene flow between this site and the other rural sites. The observed high migration rates and lack of genetic differentiation among the other P. papatasi populations could be attributed to the continuous human and cattle movement between these localities. PMID:23146340

2012-01-01

90

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

NASA Astrophysics Data System (ADS)

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 ?m) content, free Fe (Fed), Fed/Fet ratios and other soil weathering indices of the QRC (? < 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 (?), 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.

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

2014-04-01

91

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

USGS Publications Warehouse

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.

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

1993-01-01

92

Status of shark resources in the southern Gulf of Mexico and Caribbean: implications for management  

Microsoft Academic Search

This paper reviews current knowledge on shark biology, ecology, and fisheries in Mexican waters of the Gulf of Mexico, focusing on management implications. Original and literature data are summarized covering distribution, migrations, nursery areas, structure of the landings and catch trends. There are at least 34 species of shark in the area, most of them from the genera Carcharhinus and

Ramón Bonfil

1997-01-01

93

Identifying potential sources of Sudan I contamination in Capsicum fruits over its growth period.  

PubMed

Sudan dyes in spices are often assumed to arise from cross-contamination or malicious addition. Here, experiments were carried out to identify the potential source of Sudan I-IV in Capsicum fruits through investigation of their contents in native Capsicum tissues, soils and associated agronomic materials. Sudan II-IV was not detected in any of the tested samples. Sudan I was found in almost all samples except for the mulching film. Sudan I concentrations decreased from stems to leaves and then to fruits or roots. Sudan I levels in soils were significantly elevated by vegetation treatment. These results exclude the possibility of soil as the main source for Sudan I contamination in Capsicum fruits. Further study found out pesticide and fertilizer constitutes the major source of Sudan I contamination. This work represents a preliminary step for a detailed Sudan I assessment to support Capsicum management and protection in the studied region. PMID:25466000

Wu, Naiying; Gao, Wei; Zhou, Li; Lian, Yunhe; Li, Fengfei; Han, Wenjie

2015-04-15

94

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

NASA Astrophysics Data System (ADS)

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.

Álvarez-Lao, Diego J.; García, Nuria

2011-07-01

95

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

96

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

NASA Astrophysics Data System (ADS)

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.

Peña, Sherrie A.; Abdelsalam, Mohamed G.

2006-02-01

97

Oceanic pollution and the Southern Ocean: rethinking the international legal implications for Antarctica  

SciTech Connect

The author makes a critical examination of the nature of maritime pollution and the threat it poses to common space resource regimes, especially that of the Southern Ocean. Accepting the premise that international law must operate to prevent further degradation of the earth's common spaces, especially the oceans and Antarctica. This article examines the political, economic, and legal nuances associated with pollution abatement for the marine environment and resource conservation/contamination prevention for the Antarctic ecosystem. It notes encouraging signs in the United Nations conference on the Law of the Sea (UNCLOS III). 209 references.

Joyner, C.C.

1984-01-01

98

Structural evolution of the Thetford Mines Ophiolite Complex, Canada: Implications for the southern Québec ophiolitic belt  

NASA Astrophysics Data System (ADS)

The Thetford Mines Ophiolite Complex (TMOC) preserves a complete ophiolitic sequence, and occupies the hanging wall of a major SE dipping normal fault, the Saint-Joseph fault. Preobduction, synobduction, and postobduction structures can be recognized in the TMOC. NS trending, preobduction, paleonormal faults are parallel to ultramafic minor intrusions, and to sheeted dykes, recording extension related to seafloor-spreading in a pericontinental suprasubduction zone basin. WNW trending synobduction, synmetamorphic fabrics are found toward the base of the TMOC and in the underlying continental margin rocks, but are absent in the upper part of the TMOC and overlying sedimentary rocks. These Ordovician (Taconian) structures record the development of a dynamothermal aureole immediately below the mantle/margin contact, and emplacement of the young ophiolite onto the continental margin. Postobduction structures include Late Silurian/Early Devonian, SE verging backthrusts and back folds that inverted the TMOC; and Middle Devonian (Acadian) NW verging folds and reverse faults. The tectonic history established for the TMOC is consistent with that of the adjacent Laurentian margin, and can be applied to the southern Québec ophiolitic belt as a whole. The structural synthesis of the ophiolitic belt, complemented with new observations and our compilation of stratigraphical, geochemical, geochronological, and petrological data, suggests that the southern Québec ophiolites may represent the remnants of the obduction of a single large slab of suprasubduction oceanic lithosphere extending for over a 100 km of strike length.

Schroetter, Jean-Michel; BéDard, Jean H.; Tremblay, Alain

2005-02-01

99

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

NASA Astrophysics Data System (ADS)

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 Niño 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.

Warrick, Jonathan A.; Milliman, John D.

2003-09-01

100

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

NASA Astrophysics Data System (ADS)

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.

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

101

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

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

102

Downscaled Climate Change Projections for the Southern Colorado Plateau: Variability and Implications for Vegetation Changes  

NASA Astrophysics Data System (ADS)

Recent and rapid forest mortality in western North America and associated changes in fire frequency and area burned are among the chief concerns of ecosystem managers. These examples of climate change surprises demonstrate nonlinear and threshold ecosystem responses to increased temperatures and severe drought. A consistent management request from climate change adaptation workshops held during the last four years in the southwest U.S. is for region-specific estimates of climate and vegetation change, in order to provide guidance for management of federal and state forest, range, and riparian preserves and land holdings. Partly in response to these concerns, and partly in the interest of improving knowledge of potential ecosystem changes and their relationships with observed changes and changes demonstrated in the paleoecological record, we developed a set of integrated climate and ecosystem analyses. We selected five of twenty-two GCMs from the PCMDI archive of IPCC AR4 model runs, based on their approximations of observed critical seasonality for vegetation in the Southern Colorado Plateau (domain: 35°- 38°N, 114°-107°W), centered on the Four Corners states. We used three key seasons in our analysis, winter (November-March), pre-monsoon (May-June), and monsoon (July- September). Projections of monthly and seasonal temperature and precipitation from our five-model ensemble indicate steadily increasing temperatures in our region of interest during the twenty-first century. By 2050, the ensemble projects increases of 3.0°C during May and June, months critical for drought stress and tree mortality, and 4.5-5.0°C by 2090. Projected temperature changes for months during the heart of winter (December and January) are on the order of 2.5°C by 2050 and 3.0°C by 2090; such changes are likely to affect snow hydrology in middle to low elevations in the Southern Colorado Plateau. Summer temperature increases are on the order of 2.5°C (2050) and 4.0°C (2090). The most striking aspect of projections of future precipitation is steadily decreasing May-June precipitation during the twenty-first century. Though absolute precipitation during this season is small, declining moisture during the arid pre-monsoon will likely decrease soil moisture, and increase drought stress - consequently, increasing vegetation susceptibility the insect outbreaks and disease. Summer precipitation projections show considerable multi-decade variability, but no substantial trends. Winter precipitation shows little interannual variability and no strong trends. By 2090, annual precipitation is projected to decline by 1-5% across much of the region, with greater declines in the southern part of the domain and increases of 1-5% in the northwestern and northeastern parts of the domain. As part of a National Institute for Climate Change Research project, these projected changes will be input into a USDA-FS vegetation response model, in order to estimate species-specific responses to projected climate changes. We expect increasing temperatures, declining annual precipitation, and extreme declines in pre-monsoon season precipitation to generate significant redistribution of some plant species in the Southern Colorado Plateau.

Garfin, G. M.; Eischeid, J. K.; Cole, K. L.; Ironside, K.; Cobb, N. S.

2008-12-01

103

Footprints of large theropod dinosaurs and implications on the age of Triassic biotas from Southern Brazil  

NASA Astrophysics Data System (ADS)

Dinosaur footprints found in an outcrop of the Caturrita Formation (Rio Grande do Sul State, Southern Brazil), associated with a diverse and well preserved record of fauna and flora, reopen the debate about its exclusive Triassic age. The studied footprints were identified as Eubrontes isp. and are interpreted as having been produced by large theropod dinosaurs. The morphological characteristics and dimensions of the footprints are more derived than those commonly found in the Carnian-Norian, and are more consistent with those found during the Rhaetian-Jurassic. The trackmaker does not correspond to any type of dinosaur yet known from Triassic rocks of Brazil. Recent studies with the paleofloristic content of this unit also support a more advanced Rhaetian or even Jurassic age for this unit.

da Silva, Rafael Costa; Barboni, Ronaldo; Dutra, Tânia; Godoy, Michel Marques; Binotto, Raquel Barros

2012-11-01

104

Paleozoic archipelagic tectonic evolution of Western Junggar, NW China: implications for continental growth of southern Altaids  

NASA Astrophysics Data System (ADS)

The Western Junggar, NW China, a dominant site for continental growth in Southern Altaids, bridges the Circum-Balkhash and Junggar belts and exposes ophiolite, igneous rocks and strata from Cambrian to Carboniferous. Recent updated data on structure, geochronology, geochemisty and paleomagnetism, integrated with previous data, present a newly Paleozoic spatial and temporal framework of Western Junggar. In Cambrian, the Western Junggar begins to birth at the Tangbale area to south, where occurs Ordovician blueschist and top-to-south vergence structures, indicating north-dipping subduction. This event triggers intra-arc extension to generate Ordovician island arc in the Hongguleleng-Xiemisitai area to north and seamount in the Mayile area, middle of Western Junggar. Until Silurian, a southeastward subduction begins in the extended back-arc basin to west of Mayile, occurring blueschist at the Barleik trench and the Nalunsuo magmatic arc, at the rear of which generates Devonian back-arc basin around the Durbut area. Meanwhile, a Silurian Xiemisitai magmatic arc has been developed at the northern part of Western Junggar, along which a northward subduction has emplaced the Tarbahatai ophiolite and generates the Carboniferous Sawur magmatic arc. At the middle part of Western Junggar, the coeval adakite and sanukitic dykes, charnockite, multiple properties of ophiolite and plutons, SSZ-like andesite, dacite and rhyolite and regional structures suggest that there develop double-subduction systems with ridge-trench interaction in Carboniferous. These features suggest that the Western Junggar experiences rollback, intra-oceanic extension and subduction polarity reversal/flip in back-arc basin settings. Furthermore, positive ?Nd(t) values and no huge movements of blocks suggest that the Western Junggar is amalgamated by juvenile elements with different orientations. Therefore, we conclude that the Western Junggar enlarges from an island arc to Paleozoic tectonic regime with island arcs and subduction-accretion complexes via continuous accretion presented as episodic events and it significantly contributes to continental growth in southern Altaids.

Zhang, Jien; Xiao, Wenjiao; Han, Chunming; Ma, Chong; Song, Dongfang

2013-04-01

105

Geochemical Characterization of Dust in the Southern Ocean, Provenance and Paleoclimatic implications  

NASA Astrophysics Data System (ADS)

Wind-blown dust can be used to trace past and present atmospheric circulation patterns, through the study of its geographical provenance, its spatial distribution and temporal variability. Antarctic and marine records indicate that Patagonia has been a principal source of dust for the southern latitudes, particularly during glacial times. To improve our understanding of dust provenance and transport mechanisms downstream from South America and part-way to Antarctica, we analyzed the fine (<5 ?m) fraction terrigenous input into the Southern Ocean by studying the 12.76-m piston core TNO57-6, from 3751 m water depth on the Agulhas Ridge in the Southeast Atlantic, north of the present-day position of the Subantarctic Front and South of the Subtropical Convergence Zone. Due to this core's location and depth, and the position of the winds and marine currents, we suggest that the major input of sediment comes from wind-blown dust material originating in South America. To fingerprint better the terrigenous detritus, we measured chemical compositions and Sr-Nd-Pb-He isotope ratios in samples ranging in age from present-day to MIS 6. Additionally we analyzed material from potential dust source areas in different locations in Patagonia to refine their geochemical signatures. Our first results suggest that the glacial and interglacial samples have different provenances, and that the purely Patagonian sources may represent only the glacial end-member of the dust reaching that location. Further analyses at higher time resolution in the marine record will improve understanding of the relationships between the dust arriving at the site with changing climate, and continued study of potential source area samples (including Patagonia and farther North in La Puna and Altiplano) will help define the other end-member in the dust composition, and thus the more active dust sources during interglacial intervals.

Recasens, C.; Goldstein, S. L.; Winckler, G.; Kaplan, M. R.; Gili, S.; Gaiero, D. M.; Anderson, R. F.

2013-12-01

106

Assessing dengue infection risk in the southern region of Taiwan: implications for control.  

PubMed

SUMMARY Dengue, one of the most important mosquito-borne diseases, is a major international public health concern. This study aimed to assess potential dengue infection risk from Aedes aegypti in Kaohsiung and the implications for vector control. Here we investigated the impact of dengue transmission on human infection risk using a well-established dengue-mosquito-human transmission dynamics model. A basic reproduction number (R 0)-based probabilistic risk model was also developed to estimate dengue infection risk. Our findings confirm that the effect of biting rate plays a crucial role in shaping R 0 estimates. We demonstrated that there was 50% risk probability for increased dengue incidence rates exceeding 0·5-0·8 wk-1 for temperatures ranging from 26°C to 32°C. We further demonstrated that the weekly increased dengue incidence rate can be decreased to zero if vector control efficiencies reach 30-80% at temperatures of 19-32°C. We conclude that our analysis on dengue infection risk and control implications in Kaohsiung provide crucial information for policy-making on disease control. PMID:25007831

Liao, C-M; Huang, T-L; Cheng, Y-H; Chen, W-Y; Hsieh, N-H; Chen, S-C; Chio, C-P

2015-04-01

107

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

108

Implications of Stratigraphic and Structural Data from the Bitter Spring Region, Southern Nevada  

NASA Astrophysics Data System (ADS)

Deposition of the Tertiary Horse Spring Formation (HSF) in southern Nevada has been used to infer varying styles of extensional and strike-slip basin formation. Beard (1996) proposes an initial large contiguous basin of Rainbow Gardens age (ca. 26-18 Ma) that is subsequently broken up into sub-basins during Thumb time (16-14 Ma). A key locality to test this hypothesis is near the southern end of East and West Longwell Ridges, on the Bitter Spring USGS 1:24000 quadrangle (BSQ). However, the stratigraphic framework in this area is poorly defined. The BSQ is located west of the Overton arm of Lake Mead near the junction of the Las Vegas Valley Shear Zone and the Lake Mead Fault System. By mapping a portion of the quadrangle at 1:5000 scale, measuring detailed sections, and collecting ash samples from key localities, we investigated the structural and sedimentary framework of the area and have begun to clarify the stratigraphic relationships between members of the HSF. Faults fall into three categories: one set strikes north and dips moderately to the west; another strikes east-northeast and dips shallowly to the northwest; and the last strikes north and dips to the east. Many of these faults show an oblique sense of movement and may be related to movement on the White Basin (WBF) and Rodgers Spring Faults (Bohannon, 1983). A distinctive resistant limestone caps gypsiferous and clastic units on both sides of the north-south trending WBF. To the west of the WBF, this limestone is mapped as the Bitter Ridge Limestone Member of the HSF, whereas to the east it is mapped as the Thumb Member by Beard (unpub) and as the Rainbow Gardens Member by Bohannon (1983). We suspect that these limestones may be correlative; geochemical and petrographic fingerprinting of numerous ashes from our sections should allow correlation of these units across the WBF. In addition, sections from the east side of the WBF spaced over 1.5 km show conglomerate at the base, overlain by a sequence of red sandstone, gypsum, and carbonates (mainly oncolitic and peloidal limestone). These units show rapid lateral facies changes and thickness variation suggesting comparable changes in accommodation-space creation, possibly related to extensionally-induced subsidence. Paleocurrent data from the central portion of the mapping area indicate that flow was east- to southeast-directed, indicating that West Longwell Ridge may have been a topographic high during Thumb time. This interpretation is further supported by stratigraphic relationships near the basin margin, where conglomerate was deposited in buttress contact against Paleozoic limestones at the southern end of the ridge. Future work in this area includes continued mapping, Ar-Ar dating of ash mineral phases, and provenance analysis of sedimentary units.

Donatelle, A.; Goeden, J.; Hannon, M.; Hickson, T.; Holter, S.; Johnson, T.; Lamb, M.; Lindberg, J.

2004-05-01

109

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

NASA Astrophysics Data System (ADS)

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 ? 18O (-22.7‰ to -4.7‰) and ?D (-162% to +35%) plot along the world meteoric water line. Mean annual weighted values of ? 18O and ?D 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 ? 18O and ?D 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 ? 18O and ?D 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.

Nativ, Ronit; Riggio, Robert

110

The 2013 severe haze over southern Hebei, China: model evaluation, source apportionment, and policy implications  

NASA Astrophysics Data System (ADS)

Extremely severe and persistent haze occurred in January 2013 over eastern and northern China. The record-breaking high concentrations of fine particulate matter (PM2.5) of more than 700 ?g m-3 on hourly average and the persistence of the episodes have raised widespread, considerable public concerns. During that period, 7 of the top 10 polluted cities in China were within the Hebei Province. The three cities in southern Hebei (Shijiazhuang, Xingtai, and Handan) have been listed as the top three polluted cities according to the statistics for the first half of the year 2013. In this study, the Mesoscale Modeling System Generation 5 (MM5) and the Models-3/Community Multiscale Air Quality (CMAQ) modeling system are applied to simulate the 2013 severe winter regional hazes in East Asia and northern China at horizontal grid resolutions of 36 and 12 km, respectively, using the Multi-resolution Emission Inventory for China (MEIC). The source contributions of major source regions and sectors to PM2.5 concentrations in the three most polluted cities in southern Hebei are quantified by aiming at the understanding of the sources of the severe haze pollution in this region, and the results are compared with December 2007, the haziest month in the period 2001-2010. Model evaluation against meteorological and air quality observations indicates an overall acceptable performance and the model tends to underpredict PM2.5 and coarse particulate matter (PM10) concentrations during the extremely polluted episodes. The MEIC inventory is proven to be a good estimation in terms of total emissions of cities but uncertainties exist in the spatial allocations of emissions into fine grid resolutions within cities. The source apportionment shows that emissions from northern Hebei and the Beijing-Tianjin city cluster are two major regional contributors to the pollution in January 2013 in Shijiazhuang, compared with those from Shanxi and northern Hebei for December 2007. For Xingtai and Handan, the emissions from northern Hebei and Henan are important. The industrial and domestic sources are the most significant local contributors, and the domestic and agricultural emissions from Shandong and Henan are non-negligible regional sources, especially for Xingtai and Handan. Even in the top two haziest months (i.e., January 2013 and December 2007), a large fraction of PM2.5 in the three cities may originate from quite different regional sources. These results indicate the importance of establishing a regional joint framework of policymaking and action system to effectively mitigate air pollution in this area, not only over the Beijing-Tianjin-Hebei area, but also surrounding provinces such as Henan, Shandong, and Shanxi.

Wang, L. T.; Wei, Z.; Yang, J.; Zhang, Y.; Zhang, F. F.; Su, J.; Meng, C. C.; Zhang, Q.

2014-03-01

111

The 2013 severe haze over the southern Hebei, China: model evaluation, source apportionment, and policy implications  

NASA Astrophysics Data System (ADS)

Extremely severe and persistent haze occurred in January 2013 over the eastern and northern China. The record-breaking high concentrations of fine particulate matter (PM2.5) of more than 700 ?g m-3 on hourly average and the persistence of the episodes have raised widespread, considerable public concerns. During that period, seven of the top ten polluted cities in China were within Hebei Province. The three cities in southern Hebei, Shijiazhuang, Xingtai, and Handan, have been listed as the top three polluted cities according to the statistics for the first half year of 2013. In this study, the Mesoscale Modeling System Generation 5 (MM5) and the Models-3/Community Multiscale Air Quality (CMAQ) modeling system are applied to simulate the 2013 severe winter regional hazes in East Asia and the northern China at horizontal grid resolutions of 36 and 12 km, respectively, using the Multi-resolution Emission Inventory of China (MEIC). The source contributions of major source regions and sectors to PM2.5 concentrations in the three most-polluted cities in southern Hebei are quantified aiming at the understanding of the sources of the severe haze pollution in this region, and the results are compared with December 2007, the haziest month in 2001-2010. Model evaluation against meteorological and air quality observations indicates an overall acceptable performance and the model tends to underpredict PM2.5 and coarse particulate matter (PM10) concentrations during the extremely severe polluted episodes. The MEIC inventory is proved to be a good estimation in terms of total emissions of cities but uncertainties exist in the spatial allocations of emissions into fine grid resolutions within cities. The source apportionment shows that emissions from the northern Hebei and the Beijing-Tianjin city cluster are two major regional contributors to the pollution in January 2013 in Shijiazhuang, comparing with those from Shanxi and the northern Hebei for December 2007. For Xingtai and Handan, the emissions from the northern Hebei and Henan are important. The industrial and domestic sources are the most significant local contributors, and the domestic and agricultural emissions from Shandong and Henan are unnegligible regional sources, especially for Xingtai and Handan. Even in the top two haziest months (i.e., January 2013 and December 2007), a large fraction of PM2.5 in the three cities may originate from quite different regional sources. These results indicate the importance of establishing a regional joint framework of policymaking and action system to effectively mitigate air pollution in this area, not only over Beijing-Tianjin-Hebei area, but also surrounding provinces such as Henan, Shandong, and Shanxi.

Wang, L. T.; Wei, Z.; Yang, J.; Zhang, Y.; Zhang, F. F.; Su, J.; Meng, C. C.; Zhang, Q.

2013-11-01

112

A New Oviraptorosaur (Dinosauria: Oviraptorosauria) from the Late Cretaceous of Southern China and Its Paleoecological Implications  

PubMed Central

A new oviraptorosaur Nankangia jiangxiensis gen. et sp. nov. is described on the basis of a partial postcranial skeleton with a partial lower jaw collected from the Upper Cretaceous Nanxiong Formation of Ganzhou, in Jiangxi Province of southern China. The new taxon is diagnosed by: (1) a mandibular symphysis that is not turned down; (2) neural spines of the cranial caudal vertebrae that are wider transversely than anteroposteriorly, forming a large posterior fossa with rugose central areas; (3) a femoral neck extending at an angle of about 90 to the shaft; and (4) a ratio of femur to tibia length of 0.95. Phylogenetic analysis recovers Nankangia as basal to the oviraptorid Yulong, but more derived than Caenagnathus, which also has a mandibular symphysis that is not turned down. The coexistence of Nankangia jiangxiensis, Ganzhousaurus nankangensis, Jiangxisaurus ganzhouensis, an unnamed oviraptorid from Nanxiong Basin and Banji long suggests that they occupied distinct ecological niches. Nankangia may have been more herbivorous than carnivorous. PMID:24312233

Lü, Junchang; Yi, Laiping; Zhong, Hui; Wei, Xuefang

2013-01-01

113

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

NASA Astrophysics Data System (ADS)

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.

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

1995-08-01

114

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

PubMed Central

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

2011-01-01

115

Cyclic nature of lamination in the Tithonian Solnhofen Plattenkalk of southern Germany and its palaeoclimatic implications  

NASA Astrophysics Data System (ADS)

In the Tithonian Solnhofen Plattenkalk (Malm ? 2) of southern Germany, layers of purely micritic limestone are rhythmically interbedded with ones of marly micritic limestone. It appears that this alternation was formed under control of the Tithonian orbital variations. The Fourier spectral analysis shows that, on a decimetric to metric scale, the long-term cyclicities in the number of laminae per centimetre are in agreement with those found in the bed-thickness series, varying from 0.7 to 1.3 m cycles. The number of laminae of the Solnhofen Formation ranges from about 5,800 to about 12,800 laminae per main cycle. This indicates that, under an assumption that the main cycle of the Solnhofen Formation corresponds to the Tithonian precessional one, a single lamina represents a multi-year time interval. Particularly, in the short-term cyclic domain, the laminated sequence contains clearly millimetric cycles consisting of about two to three cyclic components. It implies that laminae formation may result from the composite effect of two or three distinct climatic processes.

Park, M.-H.; Fürsich, F. T.

2001-03-01

116

A new oviraptorosaur (Dinosauria: Oviraptorosauria) from the late cretaceous of southern China and its paleoecological implications.  

PubMed

A new oviraptorosaur Nankangia jiangxiensis gen. et sp. nov. is described on the basis of a partial postcranial skeleton with a partial lower jaw collected from the Upper Cretaceous Nanxiong Formation of Ganzhou, in Jiangxi Province of southern China. The new taxon is diagnosed by: (1) a mandibular symphysis that is not turned down; (2) neural spines of the cranial caudal vertebrae that are wider transversely than anteroposteriorly, forming a large posterior fossa with rugose central areas; (3) a femoral neck extending at an angle of about 90 to the shaft; and (4) a ratio of femur to tibia length of 0.95. Phylogenetic analysis recovers Nankangia as basal to the oviraptorid Yulong, but more derived than Caenagnathus, which also has a mandibular symphysis that is not turned down. The coexistence of Nankangia jiangxiensis, Ganzhousaurus nankangensis, Jiangxisaurus ganzhouensis, an unnamed oviraptorid from Nanxiong Basin and Banji long suggests that they occupied distinct ecological niches. Nankangia may have been more herbivorous than carnivorous. PMID:24312233

Lü, Junchang; Yi, Laiping; Zhong, Hui; Wei, Xuefang

2013-01-01

117

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

NASA Astrophysics Data System (ADS)

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.

Karstens, Jens; Berndt, Christian

2015-02-01

118

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

PubMed

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

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

2015-02-01

119

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

PubMed

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

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

2011-01-01

120

Landscape--wildfire interactions in southern Europe: implications for landscape management.  

PubMed

Every year approximately half a million hectares of land are burned by wildfires in southern Europe, causing large ecological and socio-economic impacts. Climate and land use changes in the last decades have increased fire risk and danger. In this paper we review the available scientific knowledge on the relationships between landscape and wildfires in the Mediterranean region, with a focus on its application for defining landscape management guidelines and policies that could be adopted in order to promote landscapes with lower fire hazard. The main findings are that (1) socio-economic drivers have favoured land cover changes contributing to increasing fire hazard in the last decades, (2) large wildfires are becoming more frequent, (3) increased fire frequency is promoting homogeneous landscapes covered by fire-prone shrublands; (4) landscape planning to reduce fuel loads may be successful only if fire weather conditions are not extreme. The challenges to address these problems and the policy and landscape management responses that should be adopted are discussed, along with major knowledge gaps. PMID:21741757

Moreira, Francisco; Viedma, Olga; Arianoutsou, Margarita; Curt, Thomas; Koutsias, Nikos; Rigolot, Eric; Barbati, Anna; Corona, Piermaria; Vaz, Pedro; Xanthopoulos, Gavriil; Mouillot, Florent; Bilgili, Ertugrul

2011-10-01

121

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

SciTech Connect

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.

Matthews, J.A.; McCarroll, D. (Univ. of Wales, Swansea (United Kingdom))

1994-05-01

122

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

SciTech Connect

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.

Wycisk, P. (Technical Univ., Berlin (West Germany))

1988-08-01

123

Space Radar Image of Sudan Collision Zone  

NASA Technical Reports Server (NTRS)

This is a radar image of a region in northern Sudan called the Keraf Suture that reveals newly discovered geologic features buried beneath layers of sand. This discovery is being used to guide field studies of the region and has opened up new perspectives on old problems, such as what controls the course of the Nile, a question that has perplexed geologists for centuries. The Nile is the yellowish/green line that runs from the top to the bottom of the image. A small town, Abu Dis, can be seen as the bright, white area on the east (right) bank of the Nile (about a third of the way down from the top) at the mouth of a dry stream valley or 'wadi' that drains into the river. Wadis flowing into the Nile from both east and west stand out as dark, reddish branch-like drainage patterns. The bright pink area on the west (left) side of the Nile is a region where rocks are exposed, but the area east (right) of the Nile is obscured by layers of sand, a few inches to several feet thick. Virtually everything visible on the right side of this radar image is invisible when standing on the ground or when viewing photographs or satellite images such as the United States' Landsat or the French SPOT satellite. A sharp, straight fault cuts diagonally across the image, to the right of the Nile river. The area between the fault and the Nile is part of the collision zone where the ancient continents of East and West Gondwana crashed into each other to form the supercontinent Greater Gondwana more than 600 million years ago. On this image, the Nile approaches but never crosses the fault, indicating that this fault seems to be controlling the course of the Nile in this part of Sudan. The image is centered at 19.5 degrees north latitude, 33.35 degrees east longitude, and shows an area approximately 18 km by 20 km (10 miles by 12 miles). The colors in the image are assigned to different frequencies and polarizations of the radar as follows: Red is L-band, vertically transmitted and vertically received; green is L-band, horizontally transmitted and vertically received; and blue is C-band, horizontally transmitted and vertically received. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) when it flew aboard the space shuttle Endeavour in April 1994. SIR-C/X-SAR, a joint mission of the German, Italian and United States space agencies, is part of NASA's Mission to Planet Earth.

1994-01-01

124

Landscape formation at the Deuteronilus contact in southern Isidis Planitia, Mars: Implications for an Isidis Sea?  

NASA Astrophysics Data System (ADS)

Two of the most widely studied landforms that are associated with a putative ocean that filled the northern hemisphere of Mars are (1) the Vastitas Borealis Formation (VBF), plain units that cover a larger portion of the northern lowlands of Mars, and (2) a candidate paleoshoreline, e.g., the Deuteronilus contact, which represents the outer margin of the VBF. The VBF and the Deuteronilus contact are interpreted to result from a short-lived Late Hesperian ocean that readily froze and sublimated. Similar landforms are also present in the impact basin of Isidis Planitia and suggest formation processes comparable to those that formed the VBF and the Deuteronilus contact in the northern lowlands. Our study of the Deuteronilus contact in Isidis revealed geologic evidence that possibly supports the existence of a Late Hesperian/Early Amazonian Isidis Sea. For example, numerous valleys that are incised into the plains of the southern Isidis basin rim between 82°/90°E and 3°/6°N and trend a few tens of kilometers to the north following the general topographic gradient toward the center of Isidis Planitia. A few of them reach the Deuteronilus contact and continue as sinuous ridges in the Isidis Interior Plains (IIP). Based on our findings we conclude that the geologic setting along the Deuteronilus contact, including the valleys and ridges is a result of (1) Late Hesperian short-term fluvial activity, (2) a Late Hesperian/Early Amazonian short-lived Isidis Sea that readily froze, (3) subglacial drainage and esker formation, and (4) subsequent sublimation of the proposed Isidis ice sheet. Although the fluvio-glacial model we introduce in our manuscript cannot fully explain the geologic setting, possible alternative formation models, including relief inversion and fluvio-volcanic scenarios are even less capable in explaining the observed geologic setting along the Deuteronilus contact.

Erkeling, G.; Reiss, D.; Hiesinger, H.; Ivanov, M. A.; Hauber, E.; Bernhardt, H.

2014-11-01

125

Shear wave velocity mapping of Hat Yai district, southern Thailand: implication for seismic site classification  

NASA Astrophysics Data System (ADS)

Soil characteristics play an important role in the degree of ground shaking due to local site amplification during an earthquake. The objectives of this work are to study shear wave velocity (Vs) distribution in the near surface, and to develop a seismic site classification map for soil effect characterization and seismic hazard assessment in Hat Yai district, southern Thailand. The Vs determination based on the multichannel analysis of surface waves technique, has been carried out and analyzed at 70 measuring sites throughout the district. On the basis of the weighted-average Vs in the upper 30?m depth (Vs30), a seismic site classification map, based on the National Earthquake Hazards Reduction Program (NEHRP) standard has been developed. It is found that the NEHRP site class in Hat Yai can be classified into four groups in accordance with the value of Vs30 within the range of about 150 to 1160?m?s?1. Most parts of the study area are typically classified as site class C and D. Site class C is mostly found within the colluvial and terrace deposits in the western and eastern part of the area, whereas site class D is concentrated in the alluvial sediment of the middle and northern flood plain areas. A small portion of site class B is observed in the western mountain ranges, where there is a thin overburden on the firm rock. There is a remarkably low Vs30 value at only one site, located near the main stream in the northern part of the study area. The results imply that the soil characteristics in the central and northern Hat Yai district pose a medium to high amplification rate with respect to the other regions. Although Vs data alone are insufficient to verify the potential of the amplification of ground shaking, this study provides an initial attempt to understand seismic hazards in the study area.

Yordkayhun, Sawasdee; Sujitapan, Chedtaporn; Chalermyanont, Tanit

2015-02-01

126

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

ERIC Educational Resources Information Center

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…

Sommers, Marc

2005-01-01

127

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

128

Energy Supply Potentials and Needs, and the Environmental Impact of their Use in Sudan  

Microsoft Academic Search

Sudan is an agricultural country with fertile land, plenty of water resources, livestock, forestry resources, and agricultural residues. An overview of the energy situation in Sudan is introduced with reference to the end uses and regional distribution. Energy sources are divided into two main types; conventional energy (biomass, petroleum products, and electricity); and non-conventional energy (solar, wind, hydro-electricity, etc.). Sudan

Abdeen Mustafa Omer

2002-01-01

129

Overview of renewable energy sources in the Republic of the Sudan  

Microsoft Academic Search

Sudan is an agricultural country with fertile land, plenty of water resources, livestock, forestry resources and agricultural residues. An overview of the energy situation in Sudan is introduced with reference to the end uses and regional distribution. Energy sources are divided into two main types: conventional energy (biomass, petroleum products and electricity) and non-conventional energy (solar, wind, hydro, etc.). Sudan

A. M. Omer

2002-01-01

130

Trends in Barrett's esophagus diagnosis in Southern Europe: implications for surveillance.  

PubMed

The incidence of Barrett's esophagus (BE) and esophageal adenocarcinoma has increased in Western countries in recent decades. The aim of this study is to describe the changes in incidence and prevalence of BE diagnosis, dysplasia, and adenocarcinoma development in BE patients in a South-European Mediterranean area. Retrospective population-based analyses of endoscopy and pathology reports from 1976 to 2001 was performed. Data from patients with diagnosis of BE and/or esophageal carcinoma were collected. The study period was divided in four quartiles for statistical calculations; parametric and nonparametric tests were used. A 6.9-fold increase was found in the diagnosis of long-segment BE from the first to the fourth quartile, and a 9.3-fold increase in short-segment BE from 1995 to 2000, in contrast to a much smaller increase of 1.9-fold increase in the number of upper gastrointestinal endoscopies. The adjusted incidence of BE diagnosis increased from 0.73 to 9.73 cases/100,000 (first to fourth quartile, respectively) and the adjusted prevalence from 6.51 to 76.04 cases/100,000 (1985-2001). The incidence of dysplasia was 2.13% per year (95% confidence interval: 0.05-11.3%) - 1.78% for low-grade dysplasia and 0.36% for high-grade dysplasia - giving a total incidence of 1 per 47 patient-years. The incidence of adenocarcinoma during follow-up was 0.48% per year (95% confidence interval: 0.006-2.62%), for an incidence of 1 per 210 patient-years. Nineteen patients with BE (14 long-segment BE, 5 short-segment BE) were diagnosed with esophageal adenocarcinoma, with eight being diagnosed during endoscopic surveillance. Only 14 (8%) adenocarcinoma patients diagnosed during the study period had a history of BE. BE diagnosis has dramatically increased over recent decades in our population, unrelated to an increase in endoscopies. Progression to low-grade dysplasia and adenocarcinoma is rare. Surveillance may have a low impact on the survival of adenocarcinoma patients in Southern Europe. PMID:19425201

Alcedo, Javier; Ferrández, Angel; Arenas, Juan; Sopeña, Federico; Ortego, Javier; Sainz, Ricardo; Lanas, Angel

2009-01-01

131

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

USGS Publications Warehouse

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.

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

2013-01-01

132

Pleistocene northwards fold propagation of the Jura within the southern Upper Rhine Graben: seismotectonic implications  

NASA Astrophysics Data System (ADS)

On the basis of the geophysical (seismic profiles and electric tomography), geomorphic and geological data, we re-evaluate the post-Pliocene structural interpretation of the southern Upper Rhine graben (Basel-Mulhouse area): we demonstrate a Plio-Pleistocene northward propagation of the Jura thrust and fold belt up to Mulhouse proceeding from a succession of four ˜10 km apart ramps (from north to south Ferrette, Muespach, Magstatt and Rixheim) rooted within the late Triassic evaporitic marls acting as a decollement. This domain was previously considered as having undergone an on-going continuous extension (horst of Mulhouse bounded by the Quaternary Sirentz and Dannemarie grabens). The Quaternary activity of this thin-skinned tectonics induces the growth of a sedimentary wedge whose regional slope, which comprised between 1.4° and 1° to the north, also attests to a low friction basal detachment. More into details, these ramps correspond to ˜40-50-m high jumps within the forward topographic slope. Pleistocene activity is suggested just above the Muespach ramp by the presence of a 5-10-m north-facing scarp corresponding in depth to a 3-m vertical offset of early Pleistocene alluvial deposits. Farther to the north, a stronger incision of the Rhine Würm terrace can be interpreted as the result of the growth of the Mulhouse-Rixheim frontal ramp. This northward propagation of the Jura thrust and fold belt is strongly controlled by the Oligocene structural inheritage. The development of the frontal ramp in Mulhouse has to be related to the Oligocene significant vertical offset of the Triassic evaporite along the Mulhouse Railway Station fault preventing a propagation of the decollement farther to the north. In the same way, the fold propagation is laterally segmented by the N20°E trending Oligocene fabrics (from East to West, Rhine Valley flexure fault, Allschwil-Istein fault system and Illfurth fault) which acts above the decollement as lateral ramps. To the west, the development of a shallow anticline along the Illfurth fault suggests that the thin-skinned propagation is oblique with respect to the Oligocene fabrics. It results in spacial contrast between a left-lateral-reverse and a right-lateral-normal shallow kinematics along the western and eastern lateral ramps, respectively. In depth to the east, it also induces a vertical contrast between shallow (right-lateral-normal) and deep (left-lateral given by fault plane solutions) kinematics along the Istein-Allschwill-Rhine Valley fault system. Few arguments supporting a nucleation of the Basel-1356 earthquake, the strongest event in NW Europe in the last thousand years, onto the Rhine Valley fault system beneath the decollement have been given. However, we emphasize that the above mentioned coeval thin (aseismic)- and thick (seismic)-skinned tectonics along the Istein-Allschwill-Rhine Valley fault system would make difficult both the identification and the interpretation of the surface rupture of the Basel-1356 earthquake.

Nivière, Bertrand; Winter, Thierry

2000-12-01

133

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

PubMed

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

Hamilton, Scott L; Caselle, Jennifer E

2015-01-22

134

Late Quaternary tectonics in the inner Northern Apennines (Siena Basin, southern Tuscany, Italy) and their seismotectonic implication  

NASA Astrophysics Data System (ADS)

Defining the most recent Quaternary tectonics represents a challenging task for neotectonic, palaeoseismological and seismotectonic studies. This paper focuses on an integrated approach to reconstructing the latest Quaternary deformation affecting the northern part of the Siena Basin (inner Northern Apennines, i.e., southern Tuscany, Italy) near the town of Siena, and to discuss the seismological implications. Field work and structural and stratigraphic analyses, coupled with the interpretation of reflection seismic lines, have been combined to define the geometry, kinematics and age of mesoscopic to map-scale faults which have affected the mainly Quaternary continental and Pliocene marine deposits. The resulting dataset describes a tectonic setting characterized by coeval SW- and NW-trending transtensional and normal faults, respectively, dissecting alluvial sediments younger than 23.9 ± 0.23 ka. Seismic interpretation sheds light on the geometrical setting of the faults at deeper levels, down to 1-2 km, and provides support for the presence of a wide brittle shear zone defined by conjugated fault segments, locally giving rise to an asymmetrical negative flower-like structure. Faults and their damage zones have controlled (and still control) the discharge of gas vents (mainly CO2 and H2S) and hydrothermal circulation (which deposits travertine) since at least 23.216 ± 0.124 ka. The resulting complete data set provides support for our description of the Neogene-Quaternary tectonics which were active until the late Quaternary, providing additional information about the seismotectonic framework of an area characterized by low seismicity and generally low-magnitude earthquakes (M < 4), but having experienced significant seismic events over the last few centuries.

Brogi, Andrea; Capezzuoli, Enrico; Martini, Ivan; Picozzi, Matteo; Sandrelli, Fabio

2014-05-01

135

Mycetoma in the Sudan: an update from the mycetoma research centre, university of khartoum, Sudan.  

PubMed

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

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

2015-03-01

136

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

PubMed Central

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

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

2015-01-01

137

The Role of Education in Sudan's Civil War  

ERIC Educational Resources Information Center

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…

Breidlid, Anders

2013-01-01

138

Reemerging Sudan Ebola Virus Disease in Uganda, 2011  

PubMed Central

Two large outbreaks of Ebola hemorrhagic fever occurred in Uganda in 2000 and 2007. In May 2011, we identified a single case of Sudan Ebola virus disease in Luwero District. The establishment of a permanent in-country laboratory and cooperation between international public health entities facilitated rapid outbreak response and control activities. PMID:22931687

Shoemaker, Trevor; Balinandi, Stephen; Campbell, Shelley; Wamala, Joseph Francis; McMullan, Laura K.; Downing, Robert; Lutwama, Julius; Mbidde, Edward; Ströher, Ute; Rollin, Pierre E.; Nichol, Stuart T.

2012-01-01

139

Mineral Composition of Renal Stones from the Sudan  

Microsoft Academic Search

Urolithiasis is a very frequent finding in the Sudan, but stone analysis is not routinely performed in this country. It would, however, give important evidence for the metabolic basis of stone formation. We therefore set out to analyze urinary stones in 80 Sudanese patients (45 male, 35 female), 12 of whom where children. Fourier-transformed infrared spectroscopy was used for stone

A. A. Balla; A. M. Salah; A. H. H. Khattab; A. Kambal; D. Bongartz; B. Hoppe; A. Hesse

1998-01-01

140

Sudanese Images of the Other: Education and Conflict in Sudan  

ERIC Educational Resources Information Center

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…

Breidlid, Anders

2010-01-01

141

a0005 Geographic Overviews/Africa Central and Nilotic Sudan  

E-print Network

ELSEVIER FIRSTPROOF a0005 Geographic Overviews/Africa ­ Central and Nilotic Sudan Kathleen Nicoll, used, or modified by humans. Common examples include tools, utensils, art, food remains, and other in search of food, water, and grazing land. g0065 optically stimulated luminescence (OSL) Quaternary

Nicoll, Kathleen

142

Diabetic Heel Ulcer in the Sudan: Determinants of Outcome  

Microsoft Academic Search

Heel ulceration, on average, costs 1.5 times more than metatarsal ulceration. The aim of this study was to analyze the determinant factors of healing in diabetic patients with heel ulcers and the late outcomes at Jabir Abu Eliz Diabetic Centre Khartoum, Khartoum, Sudan. Data were collected prospectively for 96 of 100 diabetic patients presenting with heel ulcers at the Jabir Abu

Haseeb E. Bakheit; Mohamed F. Mohamed; Seif ElDin I. Mahadi; Abu Bakr H. Widatalla; Mohamed A. Shawer; Amar H. Khamis; Mohamed E. Ahmed

143

The Peasant Economy of Refugee Resettlement in Eastern Sudan  

Microsoft Academic Search

This study seeks to contribute to the growing literature on migration in developing countries by placing refugee resettlement into the larger context of social transformation in agrarian societies. Eastern Sudan has experienced a massive influx of refugees during the last twenty-five years as a consequence of the longest war in postcolonial Africa. This case study examines the process of resettlement

Johnathan Bascom

1993-01-01

144

Renewable energy resources for electricity generation in Sudan  

Microsoft Academic Search

Electricity reaches only about 30% of Sudan's more than 40M population; this mainly in urban areas. Hence, a major problem for rural people is the inadequate supply of power for lighting, heating, cooking, cooling, water pumping, radio or TV communications and security services. Petroleum product supplies, including diesel, kerosene and LPG are irregular and often subject to sudden price increases.

Abdeen Mustafa Omer

2007-01-01

145

Insecticide resistance in Anopheles arabiensis in Sudan: temporal trends and underlying mechanisms  

PubMed Central

Background Malaria vector control in Sudan relies mainly on indoor residual spraying (IRS) and the use of long lasting insecticide treated bed nets (LLINs). Monitoring insecticide resistance in the main Sudanese malaria vector, Anopheles arabiensis, is essential for planning and implementing an effective vector control program in this country. Methods WHO susceptibility tests were used to monitor resistance to insecticides from all four WHO-approved classes of insecticide at four sentinel sites in Gezira state over a three year period. Insecticide resistance mechanisms were studied using PCR and microarray analyses. Results WHO susceptibility tests showed that Anopheles arabiensis from all sites were fully susceptible to bendiocarb and fenitrothion for the duration of the study (2008–2011). However, resistance to DDT and pyrethroids was detected at three sites, with strong seasonal variations evident at all sites. The 1014 F kdr allele was significantly associated with resistance to pyrethroids and DDT (P??7 in allelic tests). The 1014S allele was not detected in any of the populations tested. Microarray analysis of the permethrin-resistant population of An. arabiensis from Wad Medani identified a number of metabolic genes that were significantly over-transcribed in the field-collected resistant samples when compared to the susceptible Sudanese An. arabiensis Dongola strain. These included CYP6M2 and CYP6P3, two genes previously implicated in pyrethroid resistance in Anopheles gambiae s.s, and the epsilon-class glutathione-S-transferase, GSTe4. Conclusions These data suggest that both target-site mechanisms and metabolic mechanisms play an important role in conferring pyrethroid resistance in An. arabiensis from Sudan. Identification in An. arabiensis of candidate loci that have been implicated in the resistance phenotype in An. gambiae requires further investigation to confirm the role of these genes. PMID:24886129

2014-01-01

146

Fatty acid composition of lipid-rich myctophids and mackerel icefish ( Champsocephalus gunnari ) - Southern Ocean food-web implications  

Microsoft Academic Search

The lipid content, fatty acid composition and calorific value of seven species of mesopelagic deep-sea fish of the family Myctophidae and the mackerel icefish, Champsocephalus gunnari, important in the diet of Southern Ocean marine predators, are presented. Fish were sampled at the Kerguelen Plateau (KP) and Macquarie Ridge (MR) in the Indian and Pacific sectors of the Southern Ocean respectively,

Mary-Anne Lea; Peter D. Nichols; Gareth Wilson

2002-01-01

147

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

NASA Astrophysics Data System (ADS)

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 ?Oligocène Moyen et Supérieur du Sud du Fossé Rhénan: Evolution des milieux de dépôt en contexte de rift en marge de ?avant-pays alpin.

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

2009-04-01

148

The Prevalence of Blinding Trachoma in Northern States of Sudan  

PubMed Central

Background Despite historical evidence of blinding trachoma, there have been no widespread contemporary surveys of trachoma prevalence in the northern states of Sudan. We aimed to conduct district-level surveys in this vast region in order to map the extent of the problem and estimate the need for trachoma control interventions to eliminate blinding trachoma. Methods and Findings Separate, population based cross-sectional surveys were conducted in 88 localities (districts) in 12 northern states of Sudan between 2006 and 2010. Two-stage cluster random sampling with probability proportional to size was used to select the sample. Trachoma grading was done using the WHO simplified grading system. Key prevalence indicators were trachomatous inflammation-follicular (TF) in children aged 1–9 years and trachomatous trichiasis (TT) in adults aged 15 years and above. The sample comprised 1,260 clusters from which 25,624 households were surveyed. A total of 106,697 participants (81.6% response rate) were examined for trachoma signs. TF prevalence was above 10% in three districts and between 5% and 9% in 11 districts. TT prevalence among adults was above 1% in 20 districts (which included the three districts with TF prevalence >10%). The overall number of people with TT in the population was estimated to be 31,072 (lower and upper bounds?=?26,125–36,955). Conclusion Trachoma mapping is complete in the northern states of Sudan except for the Darfur States. The survey findings will facilitate programme planning and inform deployment of resources for elimination of trachoma from the northern states of Sudan by 2015, in accordance with the Sudan Federal Ministry of Health (FMOH) objectives. PMID:21655349

Hassan, Awad; Ngondi, Jeremiah M.; King, Jonathan D.; Elshafie, Balgesa E.; Al Ginaid, Ghada; Elsanousi, Mazin; Abdalla, Zeinab; Aziz, Nabil; Sankara, Dieudonne; Simms, Victoria; Cromwell, Elizabeth A.; Emerson, Paul M.; Binnawi, Kamal H.

2011-01-01

149

15 CFR Supplement No. 2 to Part 742 - Anti-Terrorism Controls: North Korea, Syria and Sudan Contract Sanctity Dates and Related Policies  

Code of Federal Regulations, 2012 CFR

...false Anti-Terrorism Controls: North Korea, Syria and Sudan Contract Sanctity...Anti-Terrorism Controls: North Korea, Syria and Sudan Contract Sanctity...of State has designated Cuba, North Korea, Sudan and Syria as...

2012-01-01

150

15 CFR Supplement No. 2 to Part 742 - Anti-Terrorism Controls: North Korea, Syria and Sudan Contract Sanctity Dates and Related Policies  

Code of Federal Regulations, 2014 CFR

...false Anti-Terrorism Controls: North Korea, Syria and Sudan Contract Sanctity...Anti-Terrorism Controls: North Korea, Syria and Sudan Contract Sanctity...of State has designated Cuba, North Korea, Sudan and Syria as...

2014-01-01

151

15 CFR Supplement No. 2 to Part 742 - Anti-Terrorism Controls: North Korea, Syria and Sudan Contract Sanctity Dates and Related Policies  

Code of Federal Regulations, 2013 CFR

...false Anti-Terrorism Controls: North Korea, Syria and Sudan Contract Sanctity...Anti-Terrorism Controls: North Korea, Syria and Sudan Contract Sanctity...of State has designated Cuba, North Korea, Sudan and Syria as...

2013-01-01

152

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...

153

Logistics of Guinea Worm Disease Eradication in South Sudan  

PubMed Central

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

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

2014-01-01

154

Site Response and Earthquake Design Spectra for Central Khartoum, Sudan  

Microsoft Academic Search

Khartoum, the capital of Sudan, is located at the confluence of White and Blue Niles. The city is heavily populated. Central\\u000a Khartoum with its high-rise buildings is the center of governmental and business activities and is located on a strip adjacent\\u000a to the Blue Nile. Geological and geotechnical data indicate that the subsoil conditions at Central Khartoum are characterized\\u000a by

Y. E. A. Mohamedzein; J. A. Abdalla; A. Abdelwahab

2006-01-01

155

The 2007 Rift Valley fever outbreak in Sudan.  

PubMed

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

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

2011-09-01

156

Nasopharyngeal Cancer in Sudan: Epidemiology, Clinical and Histological Characteristics  

PubMed Central

Objectives: To study the epidemiology, clinical features, staging, etiology and pathology of nasopharyngeal cancer in Sudan. Study design: This is a retrospective study. Setting: Ear, Nose and Throat Department Khartoum Teaching Hospital, Khartoum City, Sudan. Subjects and methods: Patients suspected to have nasopharyngeal cancer were assessed during the period March 2004 to May 2010. Data from confirmed cases was obtained; it included clinical and epidemiological information. Results: Three hundred and eighty five cases were studied. Bimodal age distribution of the disease was noted with two peaks, one at 15–19 years and one at 50–54 years. The male to female ratio was 2.6:1 and a distinct geographical distribution of the disease was noted, with clustering of cases in the towns of Dilling, Kadogli and the surrounding rural area of the Nuba Mountains. These areas in the Western States were reported to be of high background radiation due to naturally produced radioactive uranium. The Nuba tribe headed the list among other tribes, demonstrating a clear ethnic predilection. Sixty-eight cases presented at stage IV. There was a predominance of Type II (15.58%) and Type III (65.97%). Patients were treated by neoadjuvant chemoradiotherapy. Conclusions: NPC is an important form of cancer in Sudan. Some tribes are significantly more affected than others. Patients present with advanced disease. Environmental and genetic factors need further studies. Screening at risk populations that aim at early diagnosis and management of patients is recommended. PMID:24179400

Abdullah, Nazik E.; Adam, Ameera A.M.; Khalifa, Eman H.; EL Hassan, Lamyaa A.M.; Ibrahim, M.E.; Hamad, K.M.; El Hassan, A.M.

2011-01-01

157

Malaria risk mapping for control in the republic of Sudan.  

PubMed

Evidence shows that malaria risk maps are rarely tailored to address national control program ambitions. Here, we generate a malaria risk map adapted for malaria control in Sudan. Community Plasmodium falciparum parasite rate (PfPR) data from 2000 to 2010 were assembled and were standardized to 2-10 years of age (PfPR(2-10)). Space-time Bayesian geostatistical methods were used to generate a map of malaria risk for 2010. Surfaces of aridity, urbanization, irrigation schemes, and refugee camps were combined with the PfPR(2-10) map to tailor the epidemiological stratification for appropriate intervention design. In 2010, a majority of the geographical area of the Sudan had risk of < 1% PfPR(2-10). Areas of meso- and hyperendemic risk were located in the south. About 80% of Sudan's population in 2011 was in the areas in the desert, urban centers, or where risk was < 1% PfPR(2-10). Aggregated data suggest reducing risks in some high transmission areas since the 1960s. PMID:23033400

Noor, Abdisalan M; ElMardi, Khalid A; Abdelgader, Tarig M; Patil, Anand P; Amine, Ahmed A A; Bakhiet, Sahar; Mukhtar, Maowia M; Snow, Robert W

2012-12-01

158

N Isotopes in Nile Sediments (ethiopia, Sudan)  

NASA Astrophysics Data System (ADS)

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 s

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

2009-04-01

159

Mammalian body size changes and Plio-Pleistocene environmental shifts: implications for understanding hominin evolution in eastern and southern Africa.  

PubMed

This study examines geographic and temporal variation in three mammalian taxa co-occurring in eastern and southern Africa. The selected taxa-the spotted hyena (Crocuta crocuta), the plains zebra (Equus burchellii), and the impala (Aepyceros melampus)--are geographically widespread in modern times and are abundant in eastern and southern African Plio-Pleistocene fossil sites. Craniodental measurements of modern conspecifics from known geographic locations are compared using multivariate statistical methods to discern patterns of modern geographic variation within taxa. Modern and fossil samples are statistically compared to assess the nature and extent of inferred shifts in body size, both between modern samples and through time in each region. These results indicate that modern spotted hyenas and plains zebras exhibit mainly size variation between regions, with southern African samples possessing statistically larger craniodental metrics than eastern African samples. Comparison of fossil and modern samples reveals that the fossil assemblages do not show the same pattern of geographic variation. Significant temporal changes are more numerous between fossil and modern eastern African samples, and these changes are not mirrored by similar changes in the southern African samples. The changes experienced by taxa in eastern Africa appear to have been more extreme and wide-ranging than those in southern Africa, a presumed refugium. This result accords well with genetic studies of several large mammal species and paleoenvironmental studies suggesting that eastern African localized environments were more affected by tectonism and volcanism than were those in southern Africa. This study suggests that different evolutionary scenarios may have existed within Africa during the Plio-Pleistocene, but that both regions played unique and complementary roles in the evolution of African hominins and the broader faunal community. PMID:17915290

Reynolds, Sally Christine

2007-11-01

160

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

PubMed Central

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

Keefer, David K.; Moseley, Michael E.

2004-01-01

161

Habitat selection by the pale-headed brush-finch (Atlapetes pallidiceps) in southern Ecuador: implications for conservation  

E-print Network

Habitat selection by the pale-headed brush-finch (Atlapetes pallidiceps) in southern Ecuador-headed brush-finch (Atlapetes pallidiceps) is threatened with extinction due to habitat loss, but very little management. Habitat selection by the sympatric stripe-headed brush-finch (Buarremon torquatus) was examined

Schaefer, Martin

162

Complex Faulting in the Pacific-North America Transform Offshore Southern California And Implications on Plate Boundary Tectonics and Tsunamigenesis  

Microsoft Academic Search

Complexity in the tectonic model for Pacific-North America transform motion in the offshore southern California region is demonstrated by earthquakes near San Clemente Island and Fortymile Bank. Observed focal mechanisms show movements opposite to those predicted by the plate tectonic theory for right-slip on NW- trending transform faults and observed in other parts of the California Continental Borderland. Also, there

M. R. Legg; A. Barberopoulou

2007-01-01

163

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

Microsoft Academic Search

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

James A. Skinner; Kenneth L. Tanaka

2007-01-01

164

Paleoseismology along the 1980 surface rupture of the Irpinia fault - Implications for earthquake recurrence in the southern Apennines, Italy  

Microsoft Academic Search

The results of trenching across the scarp of the Irpinia fault, 5 km from the epicenter of the 1980 earthquake, are described. The trenches provide data on earthquake recurrence intervals, slip per event, and slip rate on the Irpinia fault, a major normal fault in the Southern Apennines fault zone. Evidence was found of four paleoearthquakes that occurred in the

Daniela Pantosti; David P. Schwartz; Gianluca Valensise

1993-01-01

165

Numerical modeling and field evidence of coastal overwash in southern New England from Hurricane Bob and implications for paleotempestology  

Microsoft Academic Search

In this paper, we examine the use of coastal overwash modeling in conjunction with geological proxy techniques to provide a more comprehensive tool for paleotempestology. Southern New England, which lies in the path of north tracking hurricanes, has been a prime location for paleotempestological studies. Hurricane Bob of 1991 is the most recent landfall in this region and has the

Kwok Fai Cheung; Liujuan Tang; Jeffrey P. Donnelly; Elyse M. Scileppi; Kam-Biu Liu; Xian-Zhong Mao; Samuel H. Houston; Richard J. Murnane

2007-01-01

166

Crustal structure beneath southern Africa and its implications for the formation and evolution of the Kaapvaal and Zimbabwe cratons  

Microsoft Academic Search

The formation of Archean crust appears to involve processes unique to early earth history. Initial results from receiver function analysis of crustal structure beneath 81 broadband stations deployed across southern Africa reveal significant differences in the nature of the crust and the crust-mantle boundary between Archean and post-Archean geologic terranes. With the notable exception of the collisional Limpopo belt, where

T. K. Nguuri; J. Gore; D. E. James; S. J. Webb; C. Wright; T. G. Zengeni; O. Gwavava; J. A. Snoke

2001-01-01

167

Habitat Associations of Hypogeous Fungi in the Southern Appalachians: Implications for the Endangered Northern Flying Squirrel (Glaucomys sabrinus coloratus)  

Microsoft Academic Search

gporocarps of hypogeous mycorrhizal fungi (truffles) are the major food of northern flying squirrels (Gluucomys satinus). The two subspecies of northern flying squir- rels that occur in the southern Appalachians, G. s. colmatus and G. s. fuscus, are endangered species which are primarily found in the ecotone between high-elevation spruce-fir and northern hardwood forests. Our objective was to determine the

SUSAN C. LOEB; FRANK H. TAINTER; EFREN CÁZARES

2000-01-01

168

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...

169

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

NASA Astrophysics Data System (ADS)

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.

Church, Stanley E.; Cox, Dennis P.; Wooden, Joseph L.; Tingley, Joseph V.; Vaughn, Robert B.

2005-12-01

170

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

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.

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

2005-01-01

171

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

ERIC Educational Resources Information Center

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…

Totten, Samuel

2014-01-01

172

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

ERIC Educational Resources Information Center

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…

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

2008-01-01

173

Removal of water-insoluble Sudan dyes by Shewanella oneidensis MR-1.  

PubMed

Decolorization of water-insoluble Sudan dyes was studied with Shewanella oneidensis MR-1, which removed 66.8%, 43.4%, 56.0% and 33.7% Sudan I-IV in 104 h, respectively and reduced Sudan I to aniline and 1-amino-2-naphthol. Lactate was identified as the most efficient electron donor for Sudan I reduction. Improved reduction performance was obtained in the presence of higher lactate or biomass concentration. The correlation between specific reduction rate and initial Sudan I concentration could be described with Michaelis-Menten kinetics (V(max)=1.8 mg Sudan I mg cell(-1) h(-1) and K(m)=5.3 mg l(-1)). The addition of anthraquinone-2-sulfonate stimulated the reduction significantly whereas the presence of 2-hydroxy-1,4-naphthoquinone had little enhancing effect. The main azoreductase activity was found with membrane-bound proteins of MR-1 and no reduction occurred when Sudan I was incubated with cell extracts. These data indicated for the first time that Shewanella could reduce solid-phase Sudan dye particles. PMID:22456237

Ji, Qiuyan; Liu, Guangfei; Zhou, Jiti; Wang, Jing; Jin, Ruofei; Lv, Hong

2012-06-01

174

GURUSWAMI, H ASTAD, SUDAN, AND ZUCKERMAN 1 Combinatorial Bounds for List Decoding  

E-print Network

GURUSWAMI, H °ASTAD, SUDAN, AND ZUCKERMAN 1 Combinatorial Bounds for List Decoding Venkatesan Guruswami Johan H°astad Madhu Sudan David Zuckerman Abstract-- Informally, an error-correcting code has-9875511, NSF Grant CCR-9912342, and NTT Award MIT2001-04. David Zuckerman's address is Department

HÃ¥stad, Johan

175

GURUSWAMI, H ASTAD, SUDAN, AND ZUCKERMAN 1 Combinatorial Bounds for List Decoding  

E-print Network

GURUSWAMI, H °ASTAD, SUDAN, AND ZUCKERMAN 1 Combinatorial Bounds for List Decoding Venkatesan Guruswami Johan H°astad Madhu Sudan David Zuckerman Abstract--Informally, an error-correcting code has "nice-9875511, NSF Grant CCR-9912342, and NTT Award MIT2001-04. David Zuckerman's address is Department

Sudan, Madhu

176

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

ERIC Educational Resources Information Center

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…

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

2013-01-01

177

Cross-border Dynamics of Violent ConflictThe Case of Sudan and Chad  

Microsoft Academic Search

Violent conflicts in Africa are often presented as ethnic strife in a framework of weak states. This article takes a diachronical actor-oriented perspective to analyse the conflict in Sudan. It shows how apparently local conflicts have been interlinked with the aims and interests of governments and opposing groups, army factions and militant organizations in the larger sub-region that Sudan is

Elke Grawert

2008-01-01

178

77 FR 3369 - Presidential Determination on the Eligibility of South Sudan To Receive Defense Articles and...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Determination on the Eligibility of South Sudan To Receive Defense Articles and Defense Services Under the Foreign Assistance Act of 1961...as amended, I hereby find that the furnishing of defense articles and defense services to the Republic of South Sudan will...

2012-01-24

179

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)

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.

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

2008-12-01

180

The fault pattern in the northern Negev and southern Coastal Plain of Israel and its hydrogeological implications for groundwater flow in the Judea Group aquifer  

NASA Astrophysics Data System (ADS)

On the basis of a broadly expanding data base, the hydrogeological properties of the Judea Group sequence in the northern Negev and southern Coastal Plain of Israel have been reassessed. The updated subsurface model is based on data derived from water- and oil-wells and on recent large-scale geophysical investigations. A new regional pattern of the reassessed geological through the subsurface of the study area has been revealed. In view of the reassessed geological and hydrological subsurface setting, it appears that the Judea Group aquifer should not be regarded as one continuous and undisturbed hydrological unit; owing to the occurrence of regional faults, its subaquifers are locally interconnected. These subaquifers, which contain mainly high-quality water, are juxtaposed, as a result of faulting, against Kurnub Group sandstones containing brackish paleowater. The latter Group is faulted against late Jurassic formations containing highly saline groundwater. In the Beer Sheva area, the Judea Group aquifer is vertically displaced against the Senonian and Eocene Mt. Scopus and Avdat Groups, which also contain brackish and saline water. In the southern Coastal Plain, major faults locally dissect also the Pleistocene Kurkar Group, facilitating inflow of Mg-rich groundwater deriving from Judea Group dolomites. The new geological evidence and its hydrogeological implications provide new solutions for previously unexplained salinization phenomena.

Weinberger, G.; Rosenthal, E.

1994-03-01

181

Timing of emplacement and deformation of the Tia Granodiorite, southern New England Fold Belt, NSW: Implications for the metamorphic history  

Microsoft Academic Search

The Tia Granodiorite, a Hillgrove Suite pluton in the southern New England Fold Belt, intruded complexly deformed metasediment and metabasite belonging to the Tia Complex, which at the time of intrusion had already been affected by two deformation events at low?T moderate?P metamorphic conditions and two overprinting deformation events at high?T low?P metamorphic conditions. Emplacement took place during D5 thrusting

P. H. G. M. Dirks; R. Offler; W. J. Collins

1993-01-01

182

Crustal velocity model along the southern Cuban margin: implications for the tectonic regime at an active plate boundary  

Microsoft Academic Search

A new 1-D velocity model along the southern Cuban margin has been determined using local earthquake data, which are the result of the merged Cuban and Jamaican catalogues. Simultaneous inversion using joint-hypocentre determination was applied to solve the coupled hypocentre-velocity model problem. We obtained a seven-layer model with an average Moho interface at 20 km. The average velocity was found

Bladimir Moreno; Margaret Grandison; Kuvvet Atakan

2002-01-01

183

The late Neoglacial ('Little Ice Age') glacier maximum in southern Norway : new 14C-dating evidence and climatic implications  

Microsoft Academic Search

Critical evidence is presented for the timing and extent of Holocene glacier variations in southern Norway based on end-moraine stratigraphy and 22 new 14C dates. Dates have been obtained from moss layers, other plant remains, peat and soil associated with outermost moraines delimiting the Neoglacial maximum extent of four glaciers in the Jotunheimen-Jostedalsbreen region. There is conclusive evidence for a

John A. Matthews

1991-01-01

184

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

Microsoft Academic Search

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

Anrudh K. Jain; Niranjan Saggurti

2012-01-01

185

Diversity and distribution of aquatic insects in Southern Brazil wetlands: implications for biodiversity conservation in a Neotropical region.  

PubMed

The selection of priority areas is an enormous challenge for biodiversity conservation. Some biogeographic methods have been used to identify the priority areas to conservation, and panbiogeography is one of them. This study aimed at the utilization of panbiogeographic tools, to identify the distribution patterns of aquatic insect genera, in wetland systems of an extensive area in the Neotropical region (approximately 280 000km2), and to compare the distribution of the biogeographic units identified by the aquatic insects, with the conservation units of Southern Brazil. We analyzed the distribution pattern of 82 genera distributed in four orders of aquatic insects (Diptera, Odonata, Ephemeroptera and Trichoptera) in Southern Brazil wetlands. Therefore, 32 biogeographic nodes corresponded to the priority areas for conservation of the aquatic insect diversity. Among this total, 13 were located in the Atlantic Rainforest, 16 in the Pampa and three amongst both biomes. The distribution of nodes showed that only 15% of the dispersion centers of insects were inserted in conservation units. The four priority areas pointed by node cluster criterion must be considered in further inclusions of areas for biodiversity conservation in Southern Brazil wetlands, since such areas present species from different ancestral biota. The inclusion of such areas into the conservation units would be a strong way to conserve the aquatic biodiversity in this region. PMID:22458224

Maltchik, Leonardo; Dalzochio, Marina Schmidt; Stenert, Cristina; Rolon, Ana Silvia

2012-03-01

186

Reexamination of the Near-Surface Airflow over the Antarctic Continent and Implications on Atmospheric Circulations at High Southern Latitudes*  

E-print Network

Reexamination of the Near-Surface Airflow over the Antarctic Continent and Implications) ABSTRACT Previous work has shown that winds in the lower atmosphere over the Antarctic continent are among the mean annual and seasonal airflow patterns over the Antarctic continent to compare with previous

Howat, Ian M.

187

Environmental determinants of the distribution of Phlebotomus orientalis in Sudan.  

PubMed

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

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

1998-12-01

188

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

PubMed Central

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

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

189

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

PubMed

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

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

190

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)

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.

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

1989-01-01

191

Late Pleistocene and Holocene uplift history of Cyprus: implications for active tectonics along the southern margin of the Anatolian microplate  

USGS Publications Warehouse

The nature of the southern margin of the Anatolian microplate during the Neogene is complex, controversial and fundamental in understanding active plate-margin tectonics and natural hazards in the Eastern Mediterranean region. Our investigation provides new insights into the Late Pleistocene uplift history of Cyprus and the Troodos Ophiolite. We provide isotopic (14C) and radiogenic (luminescence) dates of outcropping marine sediments in eastern Cyprus that identify periods of deposition during marine isotope stages (MIS) 3, 4, 5 and 6. Past sea-levels indicated by these deposits are c. 95±25 m higher in elevation than estimates of worldwide eustatic sea-level. An uplift rate of c. 1.8 mm/year and possibly as much as c. 4.1 mm/year in the past c. 26–40 ka is indicated. Holocene marine deposits also occur at elevations higher than those expected for past SL and suggest uplift rates of c. 1.2–2.1 mm/year. MIS-3 marine deposits that crop out in southern and western Cyprus indicate uniform island-wide uplift. We propose a model of tectonic wedging at a plate-bounding restraining bend as a mechanism for Late Pleistocene to Holocene uplift of Cyprus; uplift is accommodated by deformation and seismicity along the margins of the Troodos Ophiolite and re-activation of its low-angle, basal shear zone.

Harrison, R.W.; Tsiolakis, E.; Stone, B.D.; Lord, A.; McGeehin, J.P.; Mahan, S.A.; Chirico, P.

2013-01-01

192

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

SciTech Connect

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.

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

2004-06-25

193

Extensional deformation along the southern boundary of the Gyeonggi Massif, South Korea: structural characteristics, age constraints, and tectonic implications  

NASA Astrophysics Data System (ADS)

The Permo-Triassic collision of the North and South China blocks caused the development of the Dabie-Sulu Orogen in China and Songrim Orogen in the Korean Peninsula. Extension after this collision is known from the Dabie-Sulu Orogen, but post-orogenic extension is not well defined in the Korean Peninsula. Extensional deformation along the southern boundary of the Gyeonggi Massif in Korea is characterized by top-down-to-the-south ductile shearing and subsequent brittle normal faulting, and was predated by regional metamorphism and north-vergent contractional deformation. Extension occurred between ~220 and 185 Ma based on the ages of pre-extensional regional metamorphism and post-extensional pluton emplacement. 40Ar/39Ar dating of syn-extensional muscovite in quartz-mica mylonite yields an age of 187.8 ± 5.6 (2 ?) Ma, in agreement with constraints from structural relationships. Together with the extensional deformation identified along the northern boundary of the Gyeonggi Massif (~226 Ma), the extension along the southern boundary is probably related to the exhumation of the massif during late-orogenic or post-orogenic extension associated with the Songrim Orogeny of the Korean Peninsula and forms an important event in the Phanerozoic crustal evolution of East Asia.

Han, Raehee; Min, Kyoungwon; Ree, Jin-Han; Foster, David A.

2014-04-01

194

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

SciTech Connect

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.

French, D.E.

1993-04-01

195

Palliative care for cancer patients in Sudan: an overview  

PubMed Central

Sudan is facing an increasing number of cancer patients every year, and cancer is now among the top ten killer diseases in the country. The majority of cancer patients are diagnosed with an advanced type of cancer where curative treatment has little, if any, effect. The need for palliative care (PC) is urgent. In spite of this, there is no established programme for comprehensive cancer control in the country. In this article we review the state of PC services available for cancer patients. A PC service started in 2010 as an outpatient service at the main oncology centre in Sudan. With the help of international bodies, several training activities in PC were held. Currently the service includes an outpatient clinic, a nine-bed ward, and a limited home-care service. PC has started to reach two other hospitals in the country. Unfortunately, the need is still great; the services provided are not fully supported by the hospital administration. And even now, thousands of patients outside the cities of Khartoum and Medani have no access to oral morphine. PMID:25624872

Gafer, Nahla; Elhaj, Ahmed

2014-01-01

196

Palliative care for cancer patients in Sudan: an overview.  

PubMed

Sudan is facing an increasing number of cancer patients every year, and cancer is now among the top ten killer diseases in the country. The majority of cancer patients are diagnosed with an advanced type of cancer where curative treatment has little, if any, effect. The need for palliative care (PC) is urgent. In spite of this, there is no established programme for comprehensive cancer control in the country. In this article we review the state of PC services available for cancer patients. A PC service started in 2010 as an outpatient service at the main oncology centre in Sudan. With the help of international bodies, several training activities in PC were held. Currently the service includes an outpatient clinic, a nine-bed ward, and a limited home-care service. PC has started to reach two other hospitals in the country. Unfortunately, the need is still great; the services provided are not fully supported by the hospital administration. And even now, thousands of patients outside the cities of Khartoum and Medani have no access to oral morphine. PMID:25624872

Gafer, Nahla; Elhaj, Ahmed

2014-01-01

197

Molecular detection of equine trypanosomes in the Sudan.  

PubMed

Equine trypanosomosis (ET) is a protozoan disease affecting equines in many parts of the world. We examined 509 samples collected from geographically distinct regions in eastern, central and western Sudan to estimate the endemicity of ET using the generic ITS1-PCR diagnostic methods. Results revealed that horses and donkeys were infected by Trypanosoma brucei subgroup, Trypanosoma vivax, Trypanosoma simiae and Trypanosoma congolense. The prevalence of Trypanosoma spp. was higher in horses (12.7%, n=393) than in donkeys (3.4%, n=116). The highest prevalence was observed in South Darfur State (19.3%, n=202), followed by Kassala State (15.1%, n=86), Gadaref State (3.7%, n=82), and Khartoum State (2.6%, n=76). No trypanosomes were detected in the 63 samples collected from North Kurdofan State. We report for the first time the presence of T. simiae and T. congolense in horses in the Sudan. This study should alert veterinary services, authorized bodies to take action toward ET by undertaking countrywide epidemiological studies of the disease and adopting control strategies. PMID:24439848

Salim, Bashir; Bakheit, Mohammed Ahmed; Sugimoto, Chihiro

2014-03-01

198

A climate distribution model of malaria transmission in Sudan.  

PubMed

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

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

2012-11-01

199

Factors Associated with HIV/AIDS in Sudan  

PubMed Central

Objectives. To assess participants' knowledge about HIV/AIDS and to identify the factors associated with HIV/AIDS in Sudan. Methods. Observational cross-sectional study carried out at Omdurman National Voluntary Counseling and Testing Centre, Sudan covered 870 participants. Sociodemographic data as well as information related to sexual behavior were collected. Results. Most of the respondents were knowledgeable about the true transmission modes for AIDS virus. Very few respondents knew someone infected with AIDS (4.5%), died of AIDS (8.1%), accepted to live with someone infected with AIDS (4.7%) or to work with someone infected with AIDS (2.1%). Regarding sexual behavior, 96.5% had reported their first sexual experience between 20 and 30 years, with 85.7% reporting one or two partners, and only 1.8% reported using condom. Multivariate logistic regression showed that circumcision, religion, marital status, age at first sex, number of sexual partners, education level, and misconception of knowledge are the main risk factors associated with HIV/AIDS. Conclusion. Our results showed that a number of diversity risk factors were associated with HIV/AIDS. It is unlikely that a holistic approach will be found to immediately change sexual-risk-relating behavior. Interventions including sustained educational programs, promotion of condom, and encouragement of voluntary testing and active involvement of the country's political and religious leaders will be needed to alleviate this problem. PMID:23957014

Mohamed, Badreldin Abdelrhman; Mahfouz, Mohamed Salih

2013-01-01

200

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

USGS Publications Warehouse

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.

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

2007-01-01

201

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

NASA Astrophysics Data System (ADS)

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.

Skinner, James A.; Tanaka, Kenneth L.

2007-01-01

202

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)

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.

Friederich, W.; Brüstle, A.; Küperkoch, L.; Meier, T.; Lamara, S.; Egelados Working Group

2014-05-01

203

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

PubMed

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

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

204

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

PubMed Central

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

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

205

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

NASA Astrophysics Data System (ADS)

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).

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

2015-01-01

206

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

PubMed Central

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

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

2014-01-01

207

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

PubMed

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

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

208

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

USGS Publications Warehouse

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.

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

2003-01-01

209

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

PubMed

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

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

2014-09-01

210

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

PubMed Central

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

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

211

Reproductive biology and implications for management of the orange-spotted grouper Epinephelus coioides in the southern Arabian Gulf.  

PubMed

The reproductive biology of Epinephelus coioides was determined from the examination of 1455 individuals collected between July 2005 and June 2007 in the southern Arabian Gulf. Histological preparations of gonads indicated that males were either derived from a juvenile phase or the transition of postspawning females, confirming a diandric protogynous sexual pattern. The spawning season was well defined, occurring once a year during April and early May. Peaks in spawning occurred after the full and new moons and was completed within a single lunar cycle. The presence of mature males over the entire size and age range and the absence of inactive mature females during the spawning season suggested that the population was not constrained by sperm limitation. While specimens undergoing sexual transition were only observed in size and age ranges of 335-685 mm total length (L(T)) and 5-6 years, patterns in the proportion of males in size and age classes suggested that sex change occurred at a relatively constant rate after female maturation up to the maximum size (1002 mm L(T)) and age (11 years). Relationships between reproductive output and capacity with size and age indicated that conventional regulations that equate the mean size at first capture to sexual maturation are unsuitable for the management of E. coioides. The maximum age, small size and young age at sexual maturation (L(min)= 320 mm L(T), 2 years, for females and 242 mm L(T), 1 year, for males) conflict with the general pattern for large epinepheline groupers and may be a direct result of the intensive demersal fishery in the southern Arabian Gulf. PMID:20735602

Grandcourt, E M; Al Abdessalaam, T Z; Francis, F; Al Shamsi, A T; Hartmann, S A

2009-03-01

212

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

ERIC Educational Resources Information Center

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)

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

1995-01-01

213

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

PubMed

In order to effectively manage nutrient river load reductions and target remediation strategies, it is important to determine the relative contributions of diffuse and point sources across the river catchment. This study used a geographical information system (GIS) to apply phosphorus (P) export coefficients (obtained from the literature) to 58 water quality monitoring sites across a large, urbanised, mixed land use catchment, typical of southern lowland England (the River Avon, Warwickshire, UK). These coefficients were used to estimate the annual P load at each monitoring site, and also the relative contribution of point source (from sewage treatment works (STW)) and diffuse input (from both livestock and agricultural land use). The estimated annual P loads showed very close agreement (r2=0.98) with the measured total phosphorus (TP) loads. Sites with the highest proportion of P derived from STW had the highest TP concentrations and loads, and also had greater variations between seasons, with elevated P concentrations occurring during the summer months. The GIS model was re-run to determine the effect of an 80% reduction in P output from STW serving over 10,000 people, thereby assessing the effect of implementing the European Union's Urban Waste Water Treatment Directive (UWWTD). The exported TP load was reduced by 52%, but the sites with the highest TP concentrations were still those with the highest proportion of P derived from STW. The GIS model was re-run to estimate the impact of 80% P reductions at a further 11 STW of varying sizes. This reduced the total TP load by only 29 tonnes year-1, but greatly reduced the P concentrations in many highly nutrient contaminated tributaries. The number of sites with P concentrations greater than 1 mg l-1 was cut from 15 (before UWWTD implementation) to 2. These findings suggest that after UWWTD implementation, resources should focus on introducing tertiary sewage treatment at the remaining large STW, before targeting diffuse inputs. This conclusion is also likely to apply to other lowland river catchments in southern England, most of which have similar population densities to the River Avon. PMID:15907511

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

2005-05-15

214

Implications for the Formation of Transform Faults from Pliocene Basins on Isla San Jose, Southern Gulf of California  

NASA Astrophysics Data System (ADS)

Pliocene basins on islands in the southern Gulf of California offer a superb opportunity to evaluate how transform faults form in a highly oblique plate boundary. Pliocene strata are exposed in two subbasins on Isla San Jose, 100 km north of La Paz, Mexico. The subbasins have broadly similar stratigraphy and part of the basin is subsided offshore. A ~1 km thick lower sequence deepens upward from a thick alluvial fan unit through marginal marine strata to an outer shelf to upper slope mudstone (based on lithology and benthic forams). The uppermost mudstone has planktonic forams that indicate an early late Pliocene age ( ~3.5-3 Ma). There is evidence for widespread syn-sedimentary deformation in the lower sequence. The upper sequence is a ~50 - 120 m thick shallow marine calcarenite that lies across a low-angle to abruptly gradational unconformity. The overall stratigraphy represents 1 - 1.5 km of subsidence in the lower sequence before 3 Ma, followed by local tilting of the basin and rapid upward shallowing at and after 3 Ma. A late Pliocene to Quaternary unconformity lies above the basin and most Quaternary deposits are alluvial. The southern subbasin is bounded by NW-N striking Pliocene normal and normal-dextral faults, while the northern subbasin has mainly buttress unconformities and local faults along an irregular embayment. The subbasins on Isla San Jose may have initiated at the northern end of an early transform fault emanating from the Cerralvo trough, which suggests basin inception at 5 - 6 Ma. This implies a reasonable rate of subsidence for a rift basin. The rapid basin uplift indicates a major reorientation (or cessation) of Cerralvo transform faulting at ~3 Ma. Mudstone deposition at 3.5 - 3 Ma followed by basin uplift is similar to events in the Perico basin on Isla Carmen, 120 km to the NW near Loreto. These synchronous events on two separate islands may mean that the development of early transform faults acted in unison from Loreto to the mouth of the Gulf. This implies that there was a major reorganization of early transform faults to the modern configuration at 3 Ma. In contrast, later fault reorientation in the Loreto basin at 2.4 - 2 Ma suggests that there may be a northward propagation of transform fault development. The evidence from the islands shows that MCS and bathymetric data from the narrow shelf are needed to resolve the connections from the basins and faults we are studying on the islands to the main plate boundary transform spreading ridge system in the middle of the Gulf of California.

Umhoefer, P. J.; Schwennicke, T.; Ingle, J. C.; Del Margo, M. T.; Ruiz-Geraldo, G.

2001-12-01

215

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)

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.

Friederich, W.; Brüstle, A.; Küperkoch, L.; Meier, T.

2013-10-01

216

The discovery of late Quaternary basalt on Mount Bambouto: Implications for recent widespread volcanic activity in the southern Cameroon Line  

NASA Astrophysics Data System (ADS)

At the north-eastern flank of Mount Bambouto, a lateral cone, the Totap volcano, is dated at 0.480 ± 0.014 Ma, which corresponds to the most recent activity of this area. The lava is a basanite similar to the older basanites of Mount Bambouto. Two new datations of the lavas of the substratum are 11.75 ± 0.25 Ma, and 21.12 ± 0.45 Ma. A synthetic revision of the volcanic story of Mount Bambouto is proposed as follows. The first stage, ca. 21 Ma, corresponds to the building of the initial basaltic shield volcano. The second stage, from 18.5 to 15.3 Ma, is marked by the collapse of the caldera linked to the pouring out of ignimbritic rhyolites and trachytes. The third stage, from 15 to 4.5 Ma, renews with basaltic effusive activity, together with post-caldera extrusions of trachytes and phonolites. The 0.5 Ma Totap activity could be a fourth stage. In the recent Quaternary, a number of basaltic activities, similar to that of the Totap volcano, are encountered elsewhere in the Cameroon Line, from Mount Oku to Mount Cameroon. The very long-live activity at Mount Bambouto and the volcanic time-space distribution in the southern Cameroon Line are linked to the working of a hotline.

Kagou Dongmo, Armand; Nkouathio, David; Pouclet, André; Bardintzeff, Jacques-Marie; Wandji, Pierre; Nono, Alexandre; Guillou, Hervé

2010-04-01

217

Stable isotopes in cave drip waters from the semi-arid southern Portugal: implication for paleoenvironment reconstructions  

NASA Astrophysics Data System (ADS)

Paleo-environmental studies rely on proxies for which present day conditions need to be documented. Here, we present results from a nearly two years sampling program of waters in precipitation, aquifers and cave drip waters in the semi arid region of Southern Portugal where a Mediterranean type climate prevails. Isotopic compositions of precipitations at Faro, from 1978 until 2001, are available through the Global Network of Isotopes in Precipitation (GNIP) database of the International Atomic Energy Agency. In addition, we measured oxygen and hydrogen isotopic compositions of water samples collected in 2011 and 2012 at one meteorological station located 20 km apart from the cave. In the cave itself, four different dripping locations were surveyed. Finally, five wells from the aquifer flowing underneath the cave were also sampled. Whereas local meteoric water line obtained from GNIP data shows an important contribution of local evaporating waters, precipitation data from this project rather points out to a drier moisture source, exhibiting a deuterium excess of close to 16.5 oȦquifer isotopic compositions show very small variations during the 2 yr sampling period, with mean values of -4.53±0.06 o (VSMOW) and 23.39±0.81 o (VSMOW) for ?18O and ?2H, respectively. On the other hand, drip waters isotopic compositions are dependent of the sampling site, although varying linearly (?2H~13.3*?18O + 38.1, R2=0.74, p

Veiga-Pires, Cristina; Hélie, Jean-François; Hillaire-Marcel, Claude

2014-05-01

218

Tectonic implications for the along-strike variation of the Peninsular Ranges batholith, southern and Baja California  

NASA Astrophysics Data System (ADS)

The Jurassic-Cretaceous Peninsular Ranges batholith of southern and Baja California exhibits several along-strike variations that are most pronounced across the Agua Blanca fault. These variations include differences in the age of magmatism, degree of inheritance in zircons, depositional environment of volcanic strata, extra-arc basin geography, lateral extent of continentally derived flysch strata, and the structures attending juxtaposition of the two segments with the North American continental margin and with each other. We propose that these variations, when taken together, imply that the two segments of the western zone currently juxtaposed by the active Agua Blanca fault were accreted to North America diachronously and did not share a common history prior to the late Early Cretaceous. The Santiago Peak arc segment north of the fault developed on oceanic lithosphere juxtaposed with the continental margin prior to and during arc magmatism. Conversely, the Alisitos arc segment developed on oceanic lithosphere exotic to North America prior to accretion at 115 108 Ma. If this model is correct, it implies that the Agua Blanca fault initiated as a transpressional continuation of the suture joining the latter arc segment to the continent and that a large portion of the forearc that existed between them was subducted.

Wetmore, Paul H.; Schmidt, Keegan L.; Paterson, Scott R.; Herzig, Charles

2002-03-01

219

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

PubMed

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

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

2015-02-01

220

Paleoecological and taphonomic implications of insect-damaged pleistocene vertebrate remains from Rancho La Brea, southern California.  

PubMed

The La Brea Tar Pits, the world's richest and most important Late Pleistocene fossil locality, offers unsurpassed insights into southern California's past environments. Recent studies at Rancho La Brea document that insects serve as sensitive and valuable paleoecological and taphonomic indicators. Of the thousands of fossil bird and mammal bones recovered from the Tar Pits, insect trace damage is thus far almost exclusively confined to the foot bones of large herbivores, especially bison, camel, and horse species. Our laboratory experiments with dermestid and tenebrionid beetles establish that the larvae of both consume bone, producing different characteristic feeding traces and providing the first documentation that tenebrionids consume bone. The presence of carcass-exploiting insects in the Rancho La Brea biota provides insight into the taphonomy of the asphaltic bone masses and the environmental conditions under which they accumulated. The succession of dermestids, tenebrionids, and indeterminate traces on many of the foot elements, combined with the climate restrictions and life cycles of these insects, indicate that carcasses could remain unsubmerged for at least 17-20 weeks, thus providing the most reliable estimate to date. Attribution of these traces also suggests that the asphaltic fossils only accumulated during warmer intervals of the Late Pleistocene. Forensic studies need to reevaluate the role of tenebrionids in carcass decomposition and other additional insects that modify bone. PMID:23843988

Holden, Anna R; Harris, John M; Timm, Robert M

2013-01-01

221

Paleoecological and Taphonomic Implications of Insect-Damaged Pleistocene Vertebrate Remains from Rancho La Brea, Southern California  

PubMed Central

The La Brea Tar Pits, the world’s richest and most important Late Pleistocene fossil locality, offers unsurpassed insights into southern California’s past environments. Recent studies at Rancho La Brea document that insects serve as sensitive and valuable paleoecological and taphonomic indicators. Of the thousands of fossil bird and mammal bones recovered from the Tar Pits, insect trace damage is thus far almost exclusively confined to the foot bones of large herbivores, especially bison, camel, and horse species. Our laboratory experiments with dermestid and tenebrionid beetles establish that the larvae of both consume bone, producing different characteristic feeding traces and providing the first documentation that tenebrionids consume bone. The presence of carcass-exploiting insects in the Rancho La Brea biota provides insight into the taphonomy of the asphaltic bone masses and the environmental conditions under which they accumulated. The succession of dermestids, tenebrionids, and indeterminate traces on many of the foot elements, combined with the climate restrictions and life cycles of these insects, indicate that carcasses could remain unsubmerged for at least 17–20 weeks, thus providing the most reliable estimate to date. Attribution of these traces also suggests that the asphaltic fossils only accumulated during warmer intervals of the Late Pleistocene. Forensic studies need to reevaluate the role of tenebrionids in carcass decomposition and other additional insects that modify bone. PMID:23843988

Holden, Anna R.; Harris, John M.; Timm, Robert M.

2013-01-01

222

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

PubMed

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 Reocín 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

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

2008-10-01

223

Jurassic-Cretaceous history of Cuba: implications for the evolution of the southern margin of the North American plate  

SciTech Connect

The oldest Cuban sedimentary rocks, clastics of the Bajocian San Cayetano Fm. provide the earliest record of North American-Gondwana rifting as seen in Cuba. A similar clastic sequence is seen below the carbonates of the Bahamas platform. In the Pinar del Rio area, the San Cayetano is succeeded by Oxfordian limestones, the shallow water Jagua Fm. to the south and deeper water Francisco Fm. to the north. Both contain basaltic pillow lavas, related either to rifting or to leaky transform motion parallel to the margin. The Oxfordian units are overlain by Kimmeridgian to Tithonian pelagic limestones, the Guasasa and Artemisa Fms. The later interfingers with northerly derived calci-turbidites. North of the Escambray, silici-clastic fragments in late Jurassic pelagic limestones suggests that a basement high existed south of the platform until the Berriasian. The carbonate platform continues to shed debris along its southern edge throughout the Cretaceous. To the south an Aptian-Albian episode of turbidite deposition suggests that South America-Africa rifting caused tectonic disturbances in the Caribbean. Southerly derived volcanoclastics deposited during the Maastrichtian marks the start of the Cuban orogeny.

Barros, J.A.; Rosencrantz, E.

1985-01-01

224

The first report on the prevalence of pestivirus infection in camels in Sudan.  

PubMed

The role of pestivirus particularly bovine viral diarrhea virus (BVDV) in causing respiratory infections in camels was studied in four different localities in Sudan. The evaluation was carried out using ELISA, and positive specimens were further tested using direct fluorescent antibody technique (FAT) and reverse transcriptase polymerase chain reaction (RT-PCR) for confirmation. The overall detected seroprevalence of BVD in camel sera was 84.6% with the highest prevalence in Western Sudan (92.5%) and with most of positives showing 2+ and 3+ titer. Out of 186 lung specimens examined for BVDV antigen, 13 were found positive (7%) with the highest prevalence in Central Sudan. All ELISA-positive specimens were positive using FAT and RT-PCR. To our knowledge, this is the first report for the detection of BVDV antigen and antibodies in camels in Sudan. PMID:20376559

Intisar, Kamil Saeed; Ali, Yahia H; Khalafalla, Abdelmelik I; Mahasin, E A Rahman; Amin, Adil S; Taha, Khalid M

2010-08-01

225

Enhancing effect of pyrrolidone derivatives on the transdermal penetration of sulfaguanidine, aminopyrine and Sudan III.  

PubMed

The enhancing effect of pyrrolidone derivatives on the percutaneous penetration of sulfaguanidine, aminopyrine and sudan III was investigated using in vitro technique and excised rat skin. 1-Methyl (MP), 1-hexyl (HP) and 1-lauryl-2-pyrrolidone (LP) were used as penetration enhancers. Aminopyrine showed high penetration through skin although sulfaguanidine and sudan III showed little penetration. Pyrrolidone derivatives enhanced their penetrations. Especially HP and LP enhanced the penetration of sulfaguanidine to a high extent. Sudan III was not detected in the receptor phase regardless of the presence of enhancer. Pyrrolidone derivatives significantly increased the skin accumulation of sulfaguanidine, aminopyrine and sudan III. Penetration of pyrrolidone derivatives was also determined. MP and HP showed high penetrations. LP was not detectable in the receptor phase. MP, HP and LP showed high skin accumulations. These results suggested the usefulness of pyrrolidone derivatives as percutaneous penetration enhancers. PMID:2374089

Sasaki, H; Kojima, M; Nakamura, J; Shibasaki, J

1990-03-01

226

First reported isolation of Mycoplasma bovis from an outbreak of bovine mastitis in Sudan.  

PubMed

Thirty-seven isolates of Mycoplasma bovis were recovered from 42 milk samples from imported Friesian cows in Khartoum State. This is the first report on isolation of M. bovis in the Sudan. PMID:9008958

Abbas, S I

1996-01-01

227

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)

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.).

Dyess, Jonathan

228

Population Genetics of Trypanosoma evansi from Camel in the Sudan  

PubMed Central

Genetic variation of microsatellite loci is a widely used method for the analysis of population genetic structure of microorganisms. We have investigated genetic variation at 15 microsatellite loci of T. evansi isolated from camels in Sudan and Kenya to evaluate the genetic information partitioned within and between individuals and between sites. We detected a strong signal of isolation by distance across the area sampled. The results also indicate that either, and as expected, T. evansi is purely clonal and structured in small units at very local scales and that there are numerous allelic dropouts in the data, or that this species often sexually recombines without the need of the “normal” definitive host, the tsetse fly or as the recurrent immigration from sexually recombined T. brucei brucei. Though the first hypothesis is the most likely, discriminating between these two incompatible hypotheses will require further studies at much localized scales. PMID:21666799

Salim, Bashir; de Meeûs, Thierry; Bakheit, Mohammed A.; Kamau, Joseph; Nakamura, Ichiro; Sugimoto, Chihiro

2011-01-01

229

Colonial Boundaries of Africa: The Case of Ethiopia’s Boundary with Sudan  

Microsoft Academic Search

The aim of this paper is to study the merits and the demerits of colonial boundaries in Africa by using the Ethiopia-Sudan boundary as a case study. The paper tries to examine how the existing boundary between the two countries came into being in the early 20th century. The present-day boundary between Ethiopia and Sudan is principally the result of

Wondwosen TESHOME

2009-01-01

230

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

Microsoft Academic Search

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 ambiguous loss, relationships in the refugee camps, the

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

2008-01-01

231

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

USGS Publications Warehouse

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.

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

232

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

USGS Publications Warehouse

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.

Safran, E.B.; Anderson, S.W.; Mills-Novoa, M.; House, P.K.; Ely, L.

2011-01-01

233

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

234

Calc-silicate assemblages from the Kerala Khondalite Belt, southern India: implications for pressure-temperature-fluid histories  

NASA Astrophysics Data System (ADS)

This paper reports several new localities of wollastonite- and scapolite-bearing calc-silicate assemblages from the granulite-facies supracrustal Kerala Khondalite Belt (KKB), southern India. Based on mineralogy, these calc-silicate rocks are classified into four types: Type I, lacking wollastonite and grossular; Type II, wollastonite-bearing but grossular-absent; Type III, wollastonite- and grossular-bearing; and Type IV, dolomitic marbles. Detailed petrographic studies reveal a variety of reaction textures overprinting the polygonal granoblastic peak metamorphic assemblages in these rocks. The Type II calc-silicate rocks preserve reaction textures, including meionite breaking down to anorthite-calcite-quartz, wollastonite breaking down to calcite-quartz and meionite-quartz symplectites after K-feldspar and wollastonite. Type III calc-silicate rocks have porphyroblastic and coronal grossular. Grossular-quartz coronas separating wollastonite and anorthite and the development of grossular within the anorthite-calcite-quartz pseudomorphs of meionite form important retrograde reaction textures in this type. In Type IV dolomitic marble assemblages, meionite forming in grain boundaries of calcite and feldspars, forsterite rimmed by diopside-dolomite and the formation of grossular in feldspar-rich zones are the important textures. Calculated partial petrogenetic grids in the CaO?Al 2O 3?SiO 2?CO 2 system are used to deduce the pressure-temperature-fluid evolution of the calc-silicate rocks. The Type II assemblages provide CO 2 activity estimates of > 0.5, with a peak metamorphic temperature of about 790°C. Initial cooling followed by later CO 2 influx can be deduced from reaction modelling in these calc-silicate rocks. Type III assemblages are characterized by internal fluid buffering throughout their tectonic history. The formation of coronal grossular indicates an initial cooling from peak metamorphic temperatures of about 830°C deduced from vapour-absent meionite and grossular equilibria. Type IV marble assemblages also indicate internal fluid buffering followed by localized CO 2 influx. Overall, the calc-silicate rocks of the KKB define peak metamorphic temperatures in the range of 790-850°C, with an internally buffered fluid composition during the peak conditions. Initial cooling was followed by localized carbonic fluid influx that also post-dated decompression deduced from other rock types in the KKB.

Satish-Kumar, M.; Santosh, M.; Harley, S. L.; Yoshida, M.

235

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

NASA Astrophysics Data System (ADS)

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.

Horne, D. J.

2009-04-01

236

Foot and mouth disease in the Borana pastoral system, southern Ethiopia and implications for livelihoods and international trade.  

PubMed

Participatory epidemiology (PE) was used on the Borana plateau of southern Ethiopia to understand pastoralist's perceptions of the clinical and epidemiological features of foot and mouth disease (FMD) in cattle. Matrix scoring showed good agreement between informant groups on the clinical signs of acute and chronic FMD, and findings were cross-checked by clinical examination of cattle and assessment of previous clinical FMD at herd level by detection of antibody to non structural proteins of FMD virus. The positive predictive value of pastoralist's diagnosis of FMD at herd level was 93.1%. The annual age-specific incidence and mortality of acute FMD in 50 herds was estimated using proportional piling. The estimated mean incidence of acute FMD varied from in 18.5% in cattle less than two years of age to 14.0% in cattle three to four years of age. The estimated mean mortality due to acute FMD varied from 2.8% in cattle less than two years of age to 0.3% in cattle three of age or older. Pearson correlation coefficients for acute FMD by age group were -0.12 (p>0.05) for incidence and -0.59 (p<0.001) for mortality. Estimates of the annual incidence of chronic FMD varied from 0.2% in cattle less than two years of age to 1.8% in cattle three to four years of age. The Pearson correlation coefficient for the incidence of chronic FMD by age group was 0.47 (p<0.001). Outbreaks of FMD peaked in Borana cattle during the two dry seasons and were attributed to increased cattle movement to dry season grazing areas. The mean seroprevalence of FMD was estimated at 21% (n=920) and 55.2% of herds (n=116) tested seropositive. Serotyping of 120 seropositive samples indicated serotypes O (99.2%), A (95.8%), SAT 2 (80%) and C (67.5%). The endemic nature of FMD in Borana pastoral herds is discussed in terms of the direct household-level impact of the disease, and the increasing export of cattle and chilled beef from Ethiopia. PMID:18551776

Rufael, T; Catley, A; Bogale, A; Sahle, M; Shiferaw, Y

2008-01-01

237

Vertical fault mapping within the Gutingkeng Formation of southern Taiwan: implications for sub-aerial mud diapir tectonics  

NASA Astrophysics Data System (ADS)

Vertical faults were mapped around the periphery of the mudstone-rich Plio-Pleistocene Gutingkeng Formation (Gtk) in southern Taiwan. The faults are manifested as black colored, penetrating shear bands that intersect bedding planes of the Gtk (shear band dips range from 60 - 90 degrees; shear band thicknesses range from several centimeters to several meters). Thin (1-2cm), friable calcite veins were found locally within the shear bands and often contain weakly developed slickensides. Where available, the sense of shear of these faults show consistent interior upward motion of the Gtk. The Chishan Fault is the southeastern bounding structure of the Gtk and where exposed, near-vertical shear bands were observed with a normal sense of shear (west-side-up). In addition, three exploratory cores drilled in 2010 along the western edge of the hanging wall of the Chishan Fault did not intersect the fault or the Gtk after nearly 200 meters of drilling. This suggests that the main Chishan Fault may not be a typical top-to-the-west reverse fault as previously mapped and does not fit the typical fold and thrust geometry that is prevalent in the western foothills of Taiwan. Instead, we interpret the collective field evidence to suggest that the Chishan Fault is a near vertical structure that is accommodating uplift of the Gtk, similar to mechanism by which sub-aqueous mud diapirs grow. A chain of mud diapirs is located off the southeastern coast of Taiwan and the Gtk may be the onshore extension of this chain. The sub-aerial mud diapir hypothesis is further supported by recent leveling data collected across the Gtk that shows the largest vertical uplift in the region to be centered within the Gtk. Finally, observations at the western end of the Highway 3 tunnel through the Chishan fault and overlying Wushan Formation indicate that there is recent west side (footwall) uplift along the Chishan Fault. The vertical faults mapped within the Gtk are significant for they may provide evidence for a long-term history of vertical tectonics in this region that has shaped the structural geometries and geologic patterns of southwestern Taiwan.

Gourley, J. R.; Lee, Y.; Ching, K.

2012-12-01

238

3-D Mohr circle construction using vein orientation data from Gadag (southern India) - Implications to recognize fluid pressure fluctuation  

NASA Astrophysics Data System (ADS)

In this paper orientations of quartz veins from the Archaean age lode-gold bearing region of Gadag (southern India) are used to determine the relative stress and fluid pressure (Pf) conditions by constructing 3-D Mohr circle. Anisotropy of magnetic susceptibility (AMS) analysis of the host massive metabasalt reveals that the magnetic foliation is NW-SE striking, which is related to early NE-SW compression (D1/D2 deformation) that affected the region. The quartz veins have a wide range of orientations, with NW-SE striking veins (steep northeasterly dips) being the most prominent. Vein emplacement is inferred to have taken place under NW-SE compression that is known to have caused late deformation (D3) in the region. It is argued that the NW-SE fabric defined the pre-existing anisotropy and channelized fluid flow during D3. The permeability was initially low, which resulted in high Pf (>?2). 3-D Mohr circle analysis indicates that the driving pressure ratio (R?) was 0.94, a condition that favoured fracturing and reactivation of fabric elements (foliations and fractures) having a wide range of orientations. This led to an increase in permeability and fluid flowed (burped) into the fractures. Resulting vein emplacement and sealing of fractures led to a reduction of Pf (?2). Thus, it is concluded that the quartz veins in the Gadag region are a consequence of an interplay between conditions that fluctuated from Pf > ?2 to Pf < ?2.

Mondal, Tridib Kumar; Mamtani, Manish A.

2013-11-01

239

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

NASA Astrophysics Data System (ADS)

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.

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

2010-01-01

240

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)

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 ?l/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.

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

2014-06-01

241

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

NASA Astrophysics Data System (ADS)

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).

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

2014-05-01

242

Environmental Magnetism of Late Quaternary Sediments From the Southern Okinawa Trough: Paleoceanographic Implications and History of the Kuroshio Current  

NASA Astrophysics Data System (ADS)

The objective of this study is to advance our understanding of the late Cenozoic environmental and paleoceanographic history of the Southern Okinawa Trough and the Kuroshio Current. Our investigation is based on the environmental magnetic record of a suite of u-channel samples that span the upper 140 m (0.42 m.y.) of ODP Site 1202. This site was drilled in the southernmost Okinawa Trough off the northeast coast of Taiwan and provides, with sedimentation rates of up to 9 m/k.y., one of the highest-resolution records of environmental and paleoceanographic change ever recovered. Variations in the concentration of fine-grained magnetite (anhysteretic remanent magnetization, ARM), magnetic grain size (ARM/k), magnetic hardness (ARM(30)/ARM(0)), and overall mineralogy (susceptibility, k) reflect fluctuations in climate, sea level, source material, and depositional environment. Eleven AMS C-14 dates of planktonic foraminifers and scaphopod samples combined with oxygen isotope stratigraphy (Wei et al., 2005) provide a relatively low- resolution, but well-defined age model. Based on the magnetic characteristics we distinguished five distinctive intervals with boundaries at 11.3, 14.3, 18.6, and 27.4 ka. From the beginning of the record at about 40 ka to 27.4 ka (MIS-3) all magnetic parameters remain remarkably constant indicating very little variation in sediment source and processes. Sea level during this time interval fluctuated at around -80 m. At 27.4 ka a significant decrease in magnetic grain size is accompanied by an increase in the amount of magnetic material. This change coincides with a drop in sea level below -80 m in the buildup to the sea level lowstand of the Last Glacial Maximum (LGM). Sediment source during this time interval was predominantly the East China Sea (Wei, 2006; Diekmann et al., in press). MIS-2 is characterized by constantly increasing magnetic grain size and a decreasing amount of magnetic material. At 14.3 ka after melt water pulse (MWP) 1A, which is expressed as a short spike in all magnetic parameters, the magnetic signature changes significantly, shows very little variability and remains constant until MWP-1B at 11.3 ka. An effect of the Younger Dryas is possibly preserved in the magnetic susceptibility signal. Associated with a significant sea level rise at the onset of the Holocene, a change in sediment source to Taiwan (Wei, 2006; Diekmann et al., in press) and the onset of the Kuroshio Current as sea level rose above -50 m, magnetic parameters shift and remain relatively constant throughout the Holocene. This allowed for the extraction of a high-resolution relative paleointensity record from 0-9.4 ka. MWP-1C is associated with a short and sudden increase in magnetic grain size.

Richter, C.; Venuti, A.; Verosub, K. L.; Wei, K.

2008-12-01

243

Guns, Southernness, and gun control  

Microsoft Academic Search

Southerners have been found to have higher levels of gun ownership than persons who reside elsewhere. This may be due to cultural factors peculiar to the Southern region. If so, this would have interesting implications for gun control initiatives. Although the differential in gun ownership has been linked to varying support or opposition to gun control, the relationship between this

Pauline Gasdow Brennan; Alan J. Lizotte; David McDowall

1993-01-01

244

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

ERIC Educational Resources Information Center

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…

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

245

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

ERIC Educational Resources Information Center

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…

Pagen, Christine Mary

2010-01-01

246

[Sudan and other illegal dyes--food adulteration].  

PubMed

As foodstuffs adulterated by illegal dyes, such as Sudan I, II, III IIV, para-Red, have appeared on the European Union market, the emergency measures to eliminate this problem have been taken. The illegal dyes are added to dried, ground chilli, curry, curcuma and to palm oil. These products are imported from countries outside the E.U. The adulteration concerns also ready to eat products which contain the ingredients mentioned above. Apart from the adulteration, the presence of illegal dyes in foodstuffs can be a threat to consumer's health. In 2003-2005 three Commission Decisions on emergency measures regarding some products which can contain illegal dyes were published. Since May 2003 to March 2006, 651 notifications on food adulteration by illegal dyes were sent to the RASFF system. As a result of the taken measures, the number of notifications have decreased. The possibility of food adulteration by illegal dyes different from the ones which are used now are considered. This is the reason why the continuation of food control and cooperation between official control authorities and food producers are necessary. PMID:17713194

Gajda, Joanna; Switka, Agnieszka; Ku?ma, Katarzyna; Jarecka, Jolanta

2006-01-01

247

Cystic echinococcosis in Mundari tribe-members of South Sudan  

PubMed Central

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 Electric’s LOGIQ Book XP with a 3C-RS 2–5 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

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

2013-01-01

248

Health status of teenage school boys in eastern Sudan.  

PubMed

In July, 1981 a health survey of teenage boys was conducted in a medical clinic in the eastern Sudan, run by the Lalmba Association, a non-profit aid organization based in the US. The study population was a group of 231 students ranging in age from 13-18, some of whom board at the school. Data consisted of a general health questionnaire, height and weight measurements, and a thorough physical examination including stool sample. Average height and weight were both less than Western teenagers, possibly due to a diet deficient in animal and plant protein and total calories. Hematocrit levels were comparable. Stool parasites were present in 31% of those surveyed, the most common being Giardia, Entamoeba histolytica, and Hymenolepsis nana. The most common symptomatic problem was dental caries (8%) and the most common asymptomatic problems were trachoma and anemia (15% and 9% respectively). Investigators noted an unexpected number of genitourinary abnormalities (6%). The study population was selective in that it was the well-off portion of the teenage population in this locality. The investigators suggest that health authorities in the area distribute trachoma prophylaxis (antibiotic eye ointment) to all school age children. PMID:4006817

Rekart, M L; Plastino, J; Carr, C

1985-01-01

249

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

PubMed

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

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

2013-01-01

250

31 CFR 538.506 - 30-day delayed effective date for pre-November 4, 1997 trade contracts involving Sudan.  

Code of Federal Regulations, 2010 CFR

...are considered to be exported upon final loading aboard the exporting conveyance in the country of export. Goods are considered...third countries for an entity operated from Sudan, or for the benefit of the Government of Sudan. The application for a...

2010-07-01

251

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

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…

Malok, Malok N.

2012-01-01

252

Gravity anomalies, Quaternary vents, and Quaternary faults in the southern Cascade Range, Oregon and California: Implications for arc and backarc evolution  

Microsoft Academic Search

Isostatic residual gravity anomalies in the southern Cascade Range of northern California and southern Oregon are spatially correlated with broad zones of Quaternary magmatism as reflected by the total volume of Quaternary volcanic products, the distribution of Quaternary vents, and the anomalously low teleseismic P wave velocities in the upper 30 km of crust. The orientation of Quaternary faults also

Richard J. Blakely; Robert L. Christiansen; Marianne Guffanti; Ray E. Wells; Julie M. Donnelly-Nolan; L. J. Patrick Muffler; Michael A. Clynne; James G. Smith

1997-01-01

253

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)

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.

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

2007-03-01

254

Seasonal variation of carbon fluxes in a sparse savanna in semi arid Sudan  

PubMed Central

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 ?mol CO2 mmol PPFD-1 during the wet season compared to the dry season. During the wet season photosynthesis increases with PPFD to about 1600 ?mol 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

Ardö, Jonas; Mölder, Meelis; El-Tahir, Bashir Awad; Elkhidir, Hatim Abdalla Mohammed

2008-01-01

255

Aspects of cratonal sedimentation: facies distribution of fluvial and shallow marine sequences in NW Sudan / SW Egypt since Silurian time  

NASA Astrophysics Data System (ADS)

The predominantly fluvial sediments, which characterize Silurian to Upper Cretaceous strata of NW-Sudan and SW-Egypt, were repeatedly interrupted by marine transgressions, which rapidly progressed toward the south since Ordovician time. Most of the thin, shallow marine deposits of different ages can be traced for more than 1000 km within the studied area of the southern Dakhla Basin, Misaha Trough and the Abyad Basin. From Silurian time onward, sheet-like sandstone units of large lateral extent within the shallow basins have been built up by vertical and lateral stacking of fluvial sandstone bodies, as well as bythe amalgamation of fluvial sequences from mainly braided to low-sinuosity river sand sandy nearshore deposits. Since sedimentological processes are closely connected with the structural history of the region and with paleogeographic and paleoclimatic conditions, a classification of distinct sequence developments can be given, due to the respective structural situation: a) Fluvial/shallow marine and predominantly fluvial cratonic sheet sandstones are attributed to a mild crustal warping structural type, partly affected by reactivated fault systems (Silurian to Lower Carboniferous, Lower Cretaceous and Upper Cretaceous strata). b) Alluvial clastic wedges, attributed to vertical block movement, have been formed by fluvial sediments in intracratonal grabens and display various facies within the alluvial paleoenvironments (predominantly Upper Carboniferous to Lower Jurassic and Upper Jurassic strata). Increasing soil-forming processes have been affecting the depositional style of the alluvial deposits from Carboniferous time onward, and became especially dominant at the Upper Cretaceous.

Wycisk, P.

256

Genetic diversity and population structure of Plasmodium vivax isolates from Sudan, Madagascar, French Guiana and Armenia.  

PubMed

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

Menegon, Michela; Durand, Patrick; Menard, Didier; Legrand, Eric; Picot, Stéphane; Nour, Bakri; Davidyants, Vladimir; Santi, Flavia; Severini, Carlo

2014-10-01

257

The Use of Sudan Grass Pastures and Other Feeds for Beef Production.  

E-print Network

or going "off feed." It was possible to market creditably finished yearling steers directly from the sudan fields by self-feeding cottonseed cake or ground ear corn with the grazing; however, carcasses of steers so fed showed yellow color of external... directly from the sudan fields. A summary of the trial, November 16, 1938 to May 15, 1939, is shown in Table 7. Discussion Lot 2, which grazed 98 days on small grain pasturage made approxi- mately 60 pounds more gain per head and at the same time...

Jones, John H.

1941-01-01

258

A New Model for Management of Mycetoma in the Sudan  

PubMed Central

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

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

259

Mycetoma herbal treatment: the Mycetoma Research Centre, Sudan experience.  

PubMed

It is still challenging and difficult to treat patients with eumycetoma; the current treatment has many side effects and has proven to be expensive and characterized by high recurrence rate, hence the poor patients' treatment compliance. Most of the patients are of low socio-economic status, have many financial constraints and hence, many of them rely on alternative and herbal medicine for the treatment of their disease. With this background, the current study was conducted to determine the prevalence of herbal medicine usage among patients with eumycetoma. This cross-sectional, observational, questionnaire-based study was conducted at the Mycetoma Research Center, University of Khartoum, Khartoum, Sudan. A convenience cohort of 311 patients with confirmed eumycetoma was invited to participate in the study after informed consent. The study showed that 42.4% of the study population used herbal medicine for the treatment of eumycetoma at some stage of their illness. The commonly used herbs were Moringa oleifera, Acacia nilotica, Citrullus colocynthis and Cuminum cyminum. Most of the patients claimed no benefits from the herbal treatment. Ninety one patients (29.3%) had encountered complications with herbal treatment. The high prevalence of herbal treatment encountered in the study can be explained by the patients' dissatisfaction with the current medical therapeutic modalities. To reduce the high prevalence of herbal medicine usage, governmental control and health policies are mandatory; likewise, native healers need to be educated in that. Moringa oleifera was the commonly used herb in this study and many reports claimed medicinal properties of this tree; hence, further in-depth studies to determine the active ingredients in the different parts of the tree and its effect are required. PMID:23991244

Ezaldeen, Eshraga A; Fahal, Ahmed Hassan; Osman, Anjom

2013-01-01

260

A new model for management of mycetoma in the Sudan.  

PubMed

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

Fahal, Ahmed; Mahgoub, El Sheikh; El Hassan, Ahmed Mohamed; Abdel-Rahman, Manar Elsheikh; Alshambaty, Yassir; Hashim, Ahmed; Hago, Ali; Zijlstra, Eduard E

2014-10-01

261

Thermochronometric analysis of the North Lunggar Rift: Implications for the timing of extension initiation and structural style of deformation in southern Tibet  

E-print Network

Active north-trending rifts in southern Tibet are kinematically linked to conjugate sets of strike-slip faults along the Bangong-Nujiang Suture zone (BNS), but the initiation age of the strike-slip faults is currently ...

Sundell, Kurt E.

2011-01-01

262

Stratigraphy and strontium geochemistry of Messinian evaporite-bearing successions of the southern Apennines foredeep, Italy: implications for the Mediterranean “salinity crisis” and regional palaeogeography  

Microsoft Academic Search

An integrated study, comprising detailed mapping, stratigraphy, evaporite facies analysis, strontium content, and 87Sr\\/86Sr ratio data, is presented for two Messinian evaporite-bearing units cropping out in Irpinia-Daunia Mountains (southern Apennines, Italy). These units record the tectonic and palaeogeographic evolution of the Messinian southern Apennine foreland basin system during the abrupt salinity crisis which occurred in the Mediterranean region. The Daunia

F. Matano; M. Barbieri; S. Di Nocera; M. Torre

2005-01-01

263

Ebola haemorrhagic fever in Sudan, 1976. Report of a WHO/International Study Team.  

PubMed

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

1978-01-01

264

Civic Education and Peacebuilding: Examples from Iraq and Sudan. Special Report 254  

ERIC Educational Resources Information Center

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…

Levine, Daniel H.; Bishai, Linda S.

2010-01-01

265

Part I: cancer in Sudan—burden, distribution, and trends breast, gynecological, and prostate cancers  

PubMed Central

Despite the growing burden of cancer worldwide, it continues to receive low priority in Africa, across the continent and specifically in Sudan. This is due to political unrest, limited health resources, and other pressing public health issues such as infectious diseases. Lack of awareness about the magnitude of the current and future cancer burden among policy makers play a major role as well. Although, the real scope of cancer in Sudan is not known, the reported cases have increased from 303 in 1967–6303 in 2010. According to Globocan estimates, the top most common cancers in both sexes are breast, non-Hodgkin lymphoma, leukemia, esophagus, and colorectum. This review is the first of four papers that focuses on cancer, its distribution and trend as well as the risk factors most common in Sudan. It is expected that cancer will increase in Sudan as a result of migration of people from rural areas to urban cities in the pursuit of a better standard of living, which has resulted in lifestyle and behavioral changes that include tobacco chewing and smoking, unhealthy dieting, and a lack of physical activity. These changes are further exacerbated by the aging population and have made the country vulnerable to many diseases including cancer. These reviews are meant to provide a better understanding and knowledge required to plan appropriate cancer-control and prevention strategies in the country. PMID:25641872

Elamin, Amany; Ibrahim, Muntaser E; Abuidris, Dafalla; Mohamed, Kamal Eldin H; Mohammed, Sulma Ibrahim

2015-01-01

266

The Naivasha Language Policy: The Language of Politics and the Politics of Language in the Sudan  

ERIC Educational Resources Information Center

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…

Abdelhay, Ashraf Kamal; Makoni, Busi; Makoni, Sinfree Bullock

2011-01-01

267

RELIGION, IDENTITIES, AND POLITICS: DEFINING MUSLIM DISCOURSES IN THE NUBA MOUNTAINS OF THE SUDAN  

Microsoft Academic Search

The author discusses the increased importance of Islam in religious and so- cial life in the Sudan, exemplified by a discussion of the interplay between an indigenous, non-Arab, non-Islamized Sudanese people, the Lafofa Nuba, and their interaction with the Arab and Islamic traditions of Suda- nese society at large. An understanding of this interaction will require types of analysis that

Leif Ole Manger

268

Part I: cancer in Sudan-burden, distribution, and trends breast, gynecological, and prostate cancers.  

PubMed

Despite the growing burden of cancer worldwide, it continues to receive low priority in Africa, across the continent and specifically in Sudan. This is due to political unrest, limited health resources, and other pressing public health issues such as infectious diseases. Lack of awareness about the magnitude of the current and future cancer burden among policy makers play a major role as well. Although, the real scope of cancer in Sudan is not known, the reported cases have increased from 303 in 1967-6303 in 2010. According to Globocan estimates, the top most common cancers in both sexes are breast, non-Hodgkin lymphoma, leukemia, esophagus, and colorectum. This review is the first of four papers that focuses on cancer, its distribution and trend as well as the risk factors most common in Sudan. It is expected that cancer will increase in Sudan as a result of migration of people from rural areas to urban cities in the pursuit of a better standard of living, which has resulted in lifestyle and behavioral changes that include tobacco chewing and smoking, unhealthy dieting, and a lack of physical activity. These changes are further exacerbated by the aging population and have made the country vulnerable to many diseases including cancer. These reviews are meant to provide a better understanding and knowledge required to plan appropriate cancer-control and prevention strategies in the country. PMID:25641872

Elamin, Amany; Ibrahim, Muntaser E; Abuidris, Dafalla; Mohamed, Kamal Eldin H; Mohammed, Sulma Ibrahim

2015-03-01

269

Relationship of the Sickle Cell Gene to the Ethnic and Geographic Groups Populating the Sudan  

Microsoft Academic Search

The presence of a geographical pattern in the distribution of the sickle cell gene (S gene) and its association with malaria is well documented. To study the distribution of the S gene among various ethnic and linguistic groups in the Sudan we analyzed a hospital-based sample of 189 sickle cell anemia (SCA) patients who reported to the Khartoum Teaching Hospital

Abdelrahim O. Mohammed; Bekhieta Attalla; Fathya M. K. Bashir; Fatima E. Ahmed; Ahmed M. El Hassan; Gafar Ibnauf; Weiying Jiang; Luigi L. Cavalli-Sforza; Zein Al Abdin Karrar; Muntaser E. Ibrahim

2006-01-01

270

Dragonflies (Insecta, Odonata) from the Red Sea Hills and the main Nile in Sudan  

Microsoft Academic Search

Twenty-one species of dragonflies are recorded from the Nile and the Red Sea Hills in the Sudan. The majority are species of africotropical origin, but wide-ranging and tolerant of strongly fluctuating environmental conditions. A small but significant fraction is restricted to the Nile Valley, and another fraction, found only in the Red Sea Hills, is composed of Eremian species of

Henri J. Dumont; Koen Martens

1984-01-01

271

Reaching out and Partnering in the Sudan through Integrated Community-Oriented Teaching  

ERIC Educational Resources Information Center

Community-university partnerships, if they are to be successful, must be firmly grounded in the context in which they take place. This paper describes the ways in which the University of Gezira in the Sudan from its very beginning was built on an understanding of rural communities. The university's Faculty of Medicine built its training around…

Abdelrahman, Samira; Al Fadil, Sumaia

2011-01-01

272

A Basic Hybrid Library Support Model to Distance Learners in Sudan  

ERIC Educational Resources Information Center

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…

Abdelrahman, Omer Hassan

2012-01-01

273

Geologic assessment of the fossil energy and geothermal potential of the Sudan  

SciTech Connect

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.

Setlow, L.W.

1983-01-01

274

Flow injection chemiluminescence determination of sudan I in hot chilli sauce.  

PubMed

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

Liu, Yanhong; Song, Zhenghua; Dong, Faxin; Zhang, Lin

2007-02-01

275

Phyllody of faba bean in the Sudan. I. Progress of symptom expression, host range and transmis-  

E-print Network

Phyllody of faba bean in the Sudan. I. Progress of symptom expression, host range and transmis bean phyllody was followed in a local susceptible cultivar, Hudeiba 72, graft-inoculated from naturally and slow development of disease, sometimes partial recovery. Symptom expression in faba bean plants

Paris-Sud XI, Université de

276

Recombinant Vesicular Stomatitis Virus Vector Mediates Postexposure Protection against Sudan Ebola Hemorrhagic Fever in Nonhuman Primates  

Microsoft Academic Search

Recombinant vesicular stomatitis virus (VSV) vectors expressing homologous filoviral glycoproteins can completely protect rhesus monkeys against Marburg virus when administered after exposure and can partially protect macaques after challenge with Zaire ebolavirus. Here, we administered a VSV vector expressing the Sudan ebolavirus (SEBOV) glycoprotein to four rhesus macaques shortly after exposure to SEBOV. All four animals survived SEBOV challenge, while

Thomas W. Geisbert; Kathleen M. Daddario-DiCaprio; Kinola J. N. Williams; Joan B. Geisbert; Anders Leung; Friederike Feldmann; Lisa E. Hensley; Heinz Feldmann; Steven M. Jones

2008-01-01

277

The impact of indoor residual spraying with malathion on malaria in refugee camps in eastern Sudan  

Microsoft Academic Search

An exploratory trial of the efficacy of indoor spraying with malathion on morbidity and mortality in refugee camps in eastern Sudan was conducted during the rainy season of 1997. The interior walls of houses from a randomly selected group of five camps were sprayed with malathion in mid-September and morbidity and mortality rates in the camps for the months October

J. D. Charlwood; M. Qassim; E. I. Elnsur; M. Donnelly; V. Petrarca; P. F. Billingsley; J. Pinto; T. Smith

2001-01-01

278

Late Holocene Environmental Change at Amara West: A New Kingdom Town on the Desert Nile in Northern Sudan  

NASA Astrophysics Data System (ADS)

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.

Spencer, Neal; Woodward, Jamie; Macklin, Mark; Dalton, Matthew

2014-05-01

279

Concomitant Infection with Leishmania donovani and L. major in Single Ulcers of Cutaneous Leishmaniasis Patients from Sudan  

PubMed Central

In Sudan human leishmaniasis occurs in different clinical forms, that is, visceral (VL), cutaneous (CL), mucocutaneous (ML), and post-kala-azar dermal leishmaniasis (PKDL). Clinical samples from 69 Sudanese patients with different clinical manifestations were subjected to a PCR targeting the cytochrome oxidase II (COII) gene for Leishmania species identification. Mixed infections were suspected due to multiple overlapping peaks presented in some sequences of the COII amplicons. Cloning these amplicons and alignment of sequences from randomly selected clones confirmed the presence of two different Leishmania species, L. donovani and L. major, in three out of five CL patients. Findings were further confirmed by cloning the ITS gene. Regarding other samples no significant genetic variations were found in patients with VL (62 patients), PKDL (one patient), or ML (one patient). The sequences clustered in a single homogeneous group within L. donovani genetic group, with the exception of one sequence clustering with L. infantum genetic group. Findings of this study open discussion on the synergetic/antagonistic interaction between divergent Leishmania species both in mammalian and vector hosts, their clinical implications with respect to parasite fitness and response to treatment, and the route of transmission with respect to vector distribution and or adaptation. PMID:24744788

Babiker, A. M.; Ravagnan, S.; Fusaro, A.; Hassan, M. M.; Bakheit, S. M.; Mukhtar, M. M.; Cattoli, G.; Capelli, G.

2014-01-01

280

Malaria control in South Sudan, 2006–2013: strategies, progress and challenges  

PubMed Central

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

2013-01-01

281

Differential gene expression in Staphylococcus aureus exposed to Orange II and Sudan III azo dyes.  

PubMed

We previously demonstrated the effects of azo dyes and their reduction metabolites on bacterial cell growth and cell viability. In this report, the effects of Orange II and Sudan III on gene expression profiling in Staphylococcus aureus ATCC BAA 1556 were analyzed using microarray and quantitative RT-PCR technology. Upon exposure to 6 ?g/ml Orange II for 18 h, 21 genes were found to be differently expressed. Among them, 8 and 13 genes were up- and down-regulated, respectively. Most proteins encoded by these differentially expressed genes involve stress response caused by drug metabolism, oxidation, and alkaline shock indicating that S. aureus could adapt to Orange II exposure through a balance between up and down regulated gene expression. Whereas, after exposure to 6 ?g/ml Sudan III for 18 h, 57 genes were differentially expressed. In which, 51 genes were up-regulated and 6 were down-regulated. Most proteins encoded by these differentially expressed genes involve in cell wall/membrane biogenesis and biosynthesis, nutrient uptake, transport and metabolite, and stress response, suggesting that Sudan III damages the bacterial cell wall or/and membrane due to binding of the dye. Further analysis indicated that all differentially expressed genes encoded membrane proteins were up-regulated and most of them serve as transporters. The result suggested that these genes might contribute to survival, persistence and growth in the presence of Sudan III. Only one gene msrA, which plays an important role in oxidative stress resistance, was found to be down-regulated after exposure to both Orange II and Sudan III. The present results suggested that both these two azo dyes can cause stress in S. aureus and the response of the bacterium to the stress is mainly related to characteristics of the azo dyes. PMID:25720844

Pan, Hongmiao; Xu, Joshua; Kweon, Oh-Gew; Zou, Wen; Feng, Jinhui; He, Gui-Xin; Cerniglia, Carl E; Chen, Huizhong

2015-05-01

282

Record of Cenozoic sedimentation from the Amanos Mountains, Southern Turkey: Implications for the inception and evolution of the Arabia–Eurasia continental collision  

Microsoft Academic Search

The sedimentary succession of the southern Amanos Mountains, bordering the eastern margin of the Karasu Rift in south central Turkey, provides a record of environmental change from the Eocene (Lutetian) to the Upper Miocene (Tortonian) that charts the final evolution of the northern margin of the Arabian plate prior to and during continental collision. Eocene shallow-marine carbonates (Hac?da?? Formation) are

Sarah J. Boulton

2009-01-01

283

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  

Microsoft Academic Search

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

Hermann Behling; Valério DePatta Pillar

2007-01-01

284

Spatial variability in microscopic deformation and composition of the Punchbowl fault, southern California: implications for mechanisms, fluid–rock interaction, and fault morphology  

Microsoft Academic Search

We examine the distribution and nature of microstructures, geochemistry, and mineralogy along two traverses across the Punchbowl fault, southern California, to determine the morphology and deformation mechanisms of the fault zone in schistose rocks. The Punchbowl fault is an exhumed fault that has two main strands of slip localization and has a total of 44 km of right-slip. Protolith in

Steven E Schulz; James P Evans

1998-01-01

285

Ignimbrite flare-up and deformation in the southern Sierra Madre Occidental, western Mexico: Implications for the late subduction history of the Farallon plate  

Microsoft Academic Search

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

Luca Ferrari; Margarita López-Martínez; José Rosas-Elguera

2002-01-01

286

Subsidence, Compaction, and Gravity Sliding: Implications for 3D Geometry, Dynamic Rupture, and Seismic Hazard of Active Basin Bounding Faults in Southern California  

Microsoft Academic Search

In southern California, high rates of measured geodetic shortening occur where active basin-bounding faults thrust early-Cenozoic rocks over young uncon- solidated sediments. This implies that compaction, subsidence, and other nonelastic processes of footwall deformation may play an important role in contributing to the high rates of observed crustal strain. Even in the absence of active tectonic short- ening, sediment compaction

Craig Nicholson; Marc J. Kamerling; Christopher C. Sorlien; Thomas E. Hopps; Jean-Pierre Gratier

2007-01-01

287

Geochemistry of Paleoproterozoic metasedimentary rocks from the Birim diamondiferous field, southern Ghana: Implications for provenance and crustal evolution at the Archean-Proterozoic boundary  

Microsoft Academic Search

Metagraywackes and metapelites from the Paleoproterozoic Birimian Supergroup in the Birim diamondiferous field, southern Ghana, were analyzed for their major and trace element contents. Compared to early Proterozoic crust, the metasedimentary rocks are enriched in ferromagnesian elements but depleted in rare earth elements (REE), high field strength elements (HFSE) (with exception of Zr), and Th. They show REE patterns similar

D. K. ASIEDU; S. B. DAMPARE; P. A SAMOAH SAKYI; B. BANOENG-YAKUBO; S. OSAE; B. J. B. NYARKO; J. MANU

288

The Zooplankton and the Zoobenthos of the White Nile and Adjoining waters in the Republic of the Sudan  

Microsoft Academic Search

1.The zooplankton and the zoobenthos of the White Nile in the Republic of the Sudan were studied from November 1963 to April 1964.2.The investigated region included the White Nile river with its tributaries, the flood-plain water bodies of the south of the Sudan and Jebel-Aulia reservoir.3.The zooplankton and the zoobenthos of the Upper Nile were monotonous. The abundance of the

A. V. Monakov

1969-01-01

289

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)

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.

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

290

Genetic Diversity of the Outer Surface Protein C Gene of Southern Borrelia Isolates and Its Possible Epidemiological, Clinical, and Pathogenetic Implications  

PubMed Central

The ospC genes of 20 southern Borrelia strains were sequenced. The strains consisted of B. burgdorferi sensu stricto, B. andersonii, B. bissettii, one undescribed genospecies, MI-8, and one probably new Borrelia species, TXW-1. A high degree of similarity exists between B. burgdorferi sensu stricto and B. bissettii and between B. bissettii and B. andersonii. Lateral transfers of the ospC gene probably occurred between B. burgdorferi sensu stricto and B. bissettii and between B. bissettii and B. andersonii. Internal gene recombination appears to occur among them. The highest degree of genetic diversity among them was observed in the two variable domains (V1 and V2), semivariable domain (SV), and the species-specific epitopes (between amino acids 28 and 31). Differences in ospC sequences among southern strains reflect diversity at the strain and genospecies levels. MI-8, which was recognized as an undescribed genospecies in our previous reports, remains distinguishable in our current analysis of ospC genes and is distinct from B. burgdorferi sensu stricto. Interestingly, another undescribed southern isolate, TXW-1, was not amplified under various PCR conditions. Compared to European B. burgdorferi sensu stricto strains, American B. burgdorferi sensu stricto strains show greater genetic heterogeneity. Southern B. burgdorferi sensu stricto, B. andersonii, and B. bissettii isolates were intermixed with each other in the phylogenetic trees. In the derived trees in our work, at least one southeastern strain of B. burgdorferi, MI-2, most closely aligns with a so-called invasive cluster that possesses many proven human-invasive strains. Transmission experiments show that MI-2 and the strains in this group of southern spirochetes are able to infect mice and hamsters and that the typical vector of Lyme disease, Ixodes scapularis, can acquire the spirochetes from infected mammals. Currently, strain MI-2 appears to be the only southern isolate among the 20 we analyzed that clusters with an OspC invasive group and thus might be invasive for humans. PMID:12089279

Lin, Tao; Oliver, Jr., James H.; Gao, Lihui

2002-01-01

291

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)

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.

Cook, D. E.; Gale, S. J.

292

Gravity anomalies, Quaternary vents, and Quaternary faults in the southern Cascade Range, Oregon and California: Implications for arc and backarc evolution  

USGS Publications Warehouse

Isostatic residual gravity anomalies in the southern Cascade Range of northern California and southern Oregon are spatially correlated with broad zones of Quaternary magmatism as reflected by the total volume of Quaternary volcanic products, the distribution of Quaternary vents, and the anomalously low teleseismic P wave velocities in the upper 30 km of crust. The orientation of Quaternary faults also appears to be related to gravity anomalies and volcanism in this area, trending generally north-south within the magmatic regions and northwest-southeast as they enter the neighboring amagmatic zones to the north and south. The relationship between gravity anomalies, vent density, and fault orientations may indicate in a broad sense the strength of the middle and upper crust. The southern Cascade Range occupies a transition zone where horizontal stress is transferred from the northwest-southeast dextral shear of the Walker Lane belt to the east-west extension characteristic of the Cascade arc in central Oregon. Faulting along north-south strikes in the volcanically active areas indicates the east-west extensional stresses in thermally weakened crust, whereas northwest faulting between the volcanically active areas reflects the northwest trending, right lateral shear strain of the Walker Lane belt. The segmentation of the arc reflected in Quaternary magmatism may be caused by differential extension behind crustal blocks of the forearc rotating clockwise with respect to North America. In this view the volcanic centers at Mount Shasta, Medicine Lake volcano, and Lassen Peak in northern California are situated along the southern parts of the trailing edges of two distinct segments of the forearc where additional extension is implied by their differential clockwise rotation. U.S. copyright. Published in 1997 by the American Geophysical Union.

Blakely, R.J.; Christiansen, R.L.; Guffanti, M.; Wells, R.E.; Donnelly-Nolan, J. M.; Muffler, L.J. Patrick; Clynne, M.A.; Smith, James G.

1997-01-01

293

Rates of Holocene chemical weathering, `Little Ice Age' glacial erosion and implications for Schmidt-hammer dating at a glacier—foreland boundary, Fåbergstølsbreen, southern Norway  

Microsoft Academic Search

Average rates of Holocene chemical weathering and `Little Ice Age' glacial erosion of bedrock are estimated across the glacier—foreland boundary of an outlet glacier of the Jostedalsbreen ice-cap, southern Norway. Estimates are derived from two types of evidence: (1) the heights of quartz veins above adjacent surfaces of granitic or granodioritic gneiss; and (2) Schmidt-hammer R-values of rock hardness. Average

Geraint Owen; John A. Matthews; Paul G. Albert

2007-01-01

294

Early Permian post-collisional high-K granitoids from Liuyuan area in southern Beishan orogen, NW China: Petrogenesis and tectonic implications  

NASA Astrophysics Data System (ADS)

Early Permian magmatism is one of the most important tectonothermal events in the Central Asian Orogenic Belt (CAOB). Early Permian granitic magmatism has been recognized from southern Beishan, NW China and they were emplaced between 275 Ma and 279 Ma according to LA-ICPMS zircon U-Pb dating. They are mainly metaluminous I-type and belong to the high-K calc-alkaline and shoshonitic series. The granitoids have calc-alkalic and alkali-calcic features. Their Sri values range from 0.7028 to 0.7047, ?Nd(t) values from - 2.5 to + 1.2 with Nd model ages (TDM) of 1.06-1.25 Ga, suggesting a mixed magma source of juvenile material with old continental crust. Furthermore, some granitoids have weak heterogeneous zircon ?Hf(t) values (- 1.7 to + 9.6) and Hf model ages (TDM2 = 0.84-1.57 Ga) that are also indicative of juvenile components with a small involvement of old continental crust. Based on geochemical and isotopic features, these high-K granitoids were derived from melting of heterogeneous crustal sources or through mixing of old continental crust with juvenile components and minor AFC (assimilation and fractional crystallization). The juvenile components probably originated from underplated basaltic magmas in response to asthenospheric upwelling. These Early Permian high-K calc-alkaline granitoids in the southern Beishan orogen were probably emplaced in a post-collisional extensional setting and suggest vertical continental crustal growth in the southern CAOB, which is the same or similar to most granitoids in CAOB. This study provides new evidence for determining the post-accretionary evolution of the southern CAOB.

Li, Shan; Wilde, Simon A.; Wang, Tao

2013-10-01

295

Exposure to Traumatic Experiences Among Asylum Seekers from Eritrea and Sudan During Migration to Israel.  

PubMed

Little is known about the experiences of displaced individuals en route to destination countries. We investigated the reported prevalence of exposure to traumatic experiences during migration among a consecutive sample of adult asylum seekers (n = 895 Eritrean, n = 149 Sudanese) who sought health services in the Physicians for Human Rights Open-Clinic in Israel. Percentage of Eritrean and Sudanese men and women who reported witnessing violence (Eritrea: men: 41.3 %, women: 29.3 %; Sudan: men: 16.8 %, women: 22.2 %) and/or being a victim of violence (Eritrea: men: 56.0 %, Women: 34.9 %; Sudan: men: 51.9 % women: 44.4 %) during migration varied by gender and country of origin. Findings highlight the need for a well-coordinated international cooperation to document and prevent these transgressions. PMID:24752982

Nakash, Ora; Langer, Benjamin; Nagar, Maayan; Shoham, Shahar; Lurie, Ido; Davidovitch, Nadav

2014-04-22

296

Pharmaceutical representatives' beliefs and practices about their professional practice: a study in Sudan.  

PubMed

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

Idris, K M; Mustafa, A F; Yousif, M A

2012-08-01

297

Petrogenesis of the Early Eocene adakitic rocks in the Napuri area, southern Lhasa: Partial melting of thickened lower crust during slab break-off and implications for crustal thickening in southern Tibet  

NASA Astrophysics Data System (ADS)

Cenozoic adakitic rocks in the Lhasa block (southern Tibet) have been widely used to trace the lateral extent of crustal thickening. However, their petrogenesis remains controversial. Here, we report geochronological and geochemical data for the Napuri intrusive rocks in the core area of the Quxu batholith, southern Lhasa. Zircon U-Pb dating suggests that they were generated at approximately 48 Ma. The studied samples show significant geochemical variations, manifested by the coexistence of three types of igneous rocks. Groups I and II rocks exhibit variable and high SiO2 (66.4-73.9 wt.%), high Al2O3 (14.0-17.4 wt.%), K2O (3.9-5.3 wt.%), Sr (273-718 ppm) and Sr/Y (18.3 to 81.3) values, and low Y (3.6 to 16 ppm), heavy rare earth element (REE) (e.g., Yb = 0.48 to 1.8 ppm), MgO (0.4-1.0 wt.%), Cr (2.9-7.4 ppm) and Ni (1.6-4.5 ppm) contents, which are similar to those of thickened lower crust-derived adakitic rocks. The Group I rocks show higher Sr/Y (77.5-81.3) ratios and lower total REE (55.5-63.2 ppm) contents with clearly positive Eu and Sr anomalies, whereas the Group II rocks have relatively lower Sr/Y (18.3-65.7) ratios and higher total REE (115-375 ppm) contents with negligible or slightly negative Eu and Sr anomalies. Group III rocks have the highest SiO2 (74.5-76.0 wt.%), Y (17.0-23.7 ppm) and Yb (2.91-3.30 ppm) contents, and the lowest Al2O3 (12.5-13.2 wt.%), Sr (81.3-141 ppm) and Sr/Y (4.8-5.9) values with distinctly negative Eu and Sr anomalies. Compared with the Jurassic-Cretaceous granitoids in southern Lhasa, the relative enrichment in Sr-Nd-Hf isotopic compositions ((87Sr/86Sr)i = 0.7049-0.7055, ?Nd(t) = - 0.3 ± 0.7 and ?Hf(t)zircon = + 3.6 ± 11.4) for the Napuri intrusive rocks indicates that they likely contained Indian continental components. The Group I and Group II rocks most probably originated from thickened mafic lower crust (amphibolite eclogites or garnet amphibolites) with garnet + rutile ± plagioclase as residual minerals in the source at > 1.5 GPa, corresponding to depths of > 50 km, and Group III rocks were probably generated by fractional crystallization of plagioclase from the adakitic magmas. Taking into account the narrow linear nature of the Eocene magmatic belt and reported synchronous asthenosphere-derived basaltic rocks in southern Lhasa, we suggest that upwelling asthenosphere triggered by the break-off of subducted Neo-Tethyan slab probably provided the required thermal conditions for lower crustal melting. The identification of Indian continental components in the Napuri intrusive rocks probably indicates that the Asia-India collision had taken place prior to their emplacement. The dramatic changes in the (La/Yb)N ratios and ?Nd(t) and ?Hf(t) values of magmatic rocks in the Gangdese area at ca. 51-46 Ma indicate that the Cenozoic crustal thickening associated with the indentation of the Indian continent began in the Early Eocene (ca. 51-46 Ma) at the latest.

Ma, Lin; Wang, Bao-Di; Jiang, Zi-Qi; Wang, Qiang; Li, Zheng-Xiang; Wyman, Derek A.; Zhao, Shou-Ren; Yang, Jin-Hui; Gou, Guo-Ning; Guo, Hai-Feng

2014-05-01

298

The first report on the prevalence of pestivirus infection in camels in Sudan  

Microsoft Academic Search

The role of pestivirus particularly bovine viral diarrhea virus (BVDV) in causing respiratory infections in camels was studied\\u000a in four different localities in Sudan. The evaluation was carried out using ELISA, and positive specimens were further tested\\u000a using direct fluorescent antibody technique (FAT) and reverse transcriptase polymerase chain reaction (RT-PCR) for confirmation.\\u000a The overall detected seroprevalence of BVD in camel

Kamil Saeed Intisar; Yahia H. Ali; AbdelMelik I. Khalafalla; E. A. Rahman Mahasin; Adil S. Amin; Khalid M. Taha

2010-01-01

299

An epidemiological survey of rheumatic fever and rheumatic heart disease in Sahafa Town, Sudan  

Microsoft Academic Search

STUDY OBJECTIVE--The aim was to determine the prevalence of rheumatic fever and rheumatic heart disease and to initiate a programme of secondary prophylaxis in Sahafa Town, Sudan. DESIGN--The study was a prospective case finding survey, carried out by a specially trained team headed by a cardiologist. SETTING--The study involved high risk school children (5-15 years of age) from Sahafa Town

S Ibrahim-Khalil; M Elhag; E Ali; F Mahgoub; S Hakiem; N Omer; S Shafie; E Mahgoub

1992-01-01

300

Climate change, conflict and development in Sudan: global neo-Malthusian narratives and local power struggles.  

PubMed

Dystopian accounts of climate change posit that it will lead to more conflict, causing state failure and mass population movements. Yet these narratives are both theoretically and empirically problematic: the conflict–environment hypothesis merges a global securitization agenda with local manipulations of Northern fears about the state of planetary ecology. Sudan has experienced how damaging this fusion of wishful thinking, power politics and top-down development can be. In the 1970s, global resource scarcity concerns were used locally to impose the fata morgana of Sudan as an Arab-African breadbasket: in the name of development, violent evictions of local communities contributed to Sudan's second civil war and associated famines. Today, Darfur has been labelled ‘the world's first climate change conflict’, masking the long-term political-economic dynamics and Sudanese agency underpinning the crisis. Simultaneously, the global food crisis is instrumentalized to launch a dam programme and agricultural revival that claim to be African answers to resource scarcity. The winners, however, are Sudan's globalized Islamist elites and foreign investors, whilst the livelihoods of local communities are undermined. Important links exist between climatic developments and security, but global Malthusian narratives about state failure and conflict are dangerously susceptible to manipulations by national elites; the practical outcomes decrease rather than increase human security. In the climate change era, the breakdown of institutions and associated violence is often not an unfortunate failure of the old system due to environmental shock, but a strategy of elites in wider processes of power and wealth accumulation and contestation. PMID:22069801

Verhoeven, Harry

2011-01-01

301

The impact of apiculture on the genetic structure of wild honeybee populations ( Apis mellifera ) in Sudan  

Microsoft Academic Search

Apiculture often relies on the importation of non-native honeybees (Apis mellifera) and large distance migratory beekeeping. These activities can cause biodiversity conflicts with the conservation of wild\\u000a endemic honeybee subspecies. We studied the impact of large scale honeybee imports on managed and wild honeybee populations\\u000a in Sudan, a centre of biodiversity of A. mellifera, using as set of linked microsatellite

Mogbel A. A. El-Niweiri; Robin F. A. Moritz

2010-01-01

302

Can the Sudan Reduce Poverty by Half by the Year 2015?  

Microsoft Academic Search

ABSTRACT: The paper investigates the feasibility of achieving ,the Millennium Development ,Goal of reducing ,poverty by half by the year 2015 in the context of Sudan. An analytical framework,for the changes in poverty over time is presented. The framework,allows an indirect method,for the calculation of the relevant variables to be used for countries that do not,have the required information. The

Ali Abdel Gadir Ali

303

Epidemiological assessment of the health and nutrition of Ethiopian refugees in emergency camps in Sudan, 1985  

Microsoft Academic Search

The findings from epidemiological data that were collected from emergency camps for Ethiopian refugees during a mass influx of refugees into Eastern Sudan in 1985 are presented. An overall mortality of 8.9 per 10,000 a day was recorded during February 1985, and in children under 5 years of age the rate was 22 per 10,000 a day. The estimated prevalence

P Shears; A M Berry; R Murphy; M A Nabil

1987-01-01

304

Aflatoxin B 1 Contamination of Traditionally Processed Peanuts Butter for Human Consumption in Sudan  

Microsoft Academic Search

A survey was carried out to detect the presence of aflatoxin B1 in 60 duplicated samples (120 samples) of peanuts butter purchased from the local markets and other traditionally prepared\\u000a and distributed by the street sellers in Khartoum state, Sudan. AflaTest-P affinity column was used to extract the toxin from\\u000a the samples, and the concentration was measured by calibrated Vicam

Sana Z. B. Elshafie; Abdullah ElMubarak; Saifeldin A. F. El-Nagerabi; Abdulkadir E. Elshafie

2011-01-01

305

A seismicity burst following the 2010 M6.4 Jiashian earthquake -implications1 for short-term seismic hazards in southern Taiwan2  

E-print Network

1 A seismicity burst following the 2010 M6.4 Jiashian earthquake - implications1 stress change; ground12 motion prediction equation; probabilistic seismic hazard assessment; Taiwan.13 14 15 #12;2 Abstract. Following the 4 March 2010 Mw 6.4 Jiashian earthquake

Wu, Yih-Min

306

A seismicity burst following the 2010 M 6.4 Jiashian earthquake implications for short-term seismic hazards in southern Taiwan  

E-print Network

A seismicity burst following the 2010 M 6.4 Jiashian earthquake ­ implications for short Smoothing Kernel function Coulomb stress change Ground motion prediction equation Probabilistic seismic hazard assessment Taiwan a b s t r a c t Following the 4 March 2010 MW 6.4 Jiashian earthquake

Wu, Yih-Min

307

Southern Appalachia: A Special Challenge  

ERIC Educational Resources Information Center

An informal survey of administrative personnel at six community colleges in North Carolina elicited perceptions of the characteristics of the Southern Appalachian people, their socioeconomic condition, their cultural influences, and the importance of community college accessibility and transportation. Implications for community college governance…

Cottingham, Tom; Cooper, Leland

1975-01-01

308

Leishmania donovani populations in Eastern Sudan: temporal structuring and a link between human and canine transmission.  

PubMed

BackgroundVisceral leishmaniasis (VL), caused by the members of the Leishmania donovani complex, has been responsible for devastating VL epidemics in the Sudan. Multilocus microsatellite and sequence typing studies can provide valuable insights into the molecular epidemiology of leishmaniasis, when applied at local scales. Here we present population genetic data for a large panel of strains and clones collected in endemic Sudan between 1993 and 2001.MethodsGenetic diversity was evaluated at fourteen microsatellite markers and eleven nuclear sequence loci across 124 strains and clones.ResultsMicrosatellite data defined six genetic subpopulations with which the nuclear sequence data were broadly congruent. Pairwise estimates of FST (microsatellite) and KST (sequence) indicated small but significant shifts among the allelic repertoires of circulating strains year on year. Furthermore, we noted the co-occurrence of human and canine L. donovani strains in three of the six clusters defined. Finally, we identified widespread deficit in heterozygosity in all four years tested but strong deviation from inter-locus linkage equilibrium in two years.ConclusionsSignificant genetic diversity is present among L. donovani in Sudan, and minor population structuring between years is characteristic of entrenched, endemic disease transmission. Seasonality in vector abundance and transmission may, to an extent, explain the shallow temporal clines in allelic frequency that we observed. Genetically similar canine and human strains highlight the role of dogs as important local reservoirs of visceral leishmaniasis. PMID:25410888

Baleela, Rania; Llewellyn, Martin S; Fitzpatrick, Sinead; Kuhls, Katrin; Schönian, Gabriele; Miles, Michael A; Mauricio, Isabel L

2014-11-20

309

Sonography of Common Carotid Arteries’ Intima: Media Thickness in the Normal Adult Population in Sudan  

PubMed Central

Background: Carotid ultrasonography is a useful diagnostic tool for assessing carotid disease. It is highly reliable, has no radiation risk, and has no risks when compared to conventional angiography. Aim: The study was to determine the common carotid artery (CCA) intima–media thickness (IMT) in the normal adult Sudanese so as to create standards for defining abnormalities. Materials and Methods: In 440 participants, the intima–media thickness was obtained sonographically in the supine position at the point of 1 cm section distal to the carotid bulb. Due to ethnic variations, participants were divided into a five ethnic groups according to their geographic distribution in Sudan. Results: The ranges of IMT found in the study were from 0.04 cm to 0.07 cm in carotids. Ethnically, males and females from West and East of Sudan show the highest IMT (0.070 ± 0.00 cm and 0.065 ± 0.01 cm) for CCA while males and females from the South of Sudan show the lowest IMT (0.055 ± 0.01 cm and 0.058 ± 0.004 cm). Conclusion: Mean carotids’ IMT was slightly higher in females compared to males. No significant differences were found between IMT and different ethnics but significance was noted among participants’ age and IMT of both sexes. PMID:23641368

Mahmoud, Mustafa Z

2013-01-01

310

Paleocene-Eocene foreland basin evolution in the Himalaya of southern Tibet and Nepal: Implications for the age of initial India-Asia collision  

NASA Astrophysics Data System (ADS)

Siliciclastic sedimentary rocks derived from the southern Lhasa terrane, sitting depositionally upon rocks of the northern Indian passive continental margin, provide an estimate of the age of initial contact between the continental parts of the Indian and Asian plates. We report sedimentological, sedimentary petrological, and geochronological data from Upper Cretaceous-Paleocene strata in the Sangdanlin section, located along the southern flank of the Indus-Yarlung suture zone in southern Tibet. This is probably the most proximal, and therefore the oldest, record of the India-Asia collision. These strata were deposited by high-density turbidity currents (or concentrated density flows) and suspension settling of pelagic biogenic debris in a deep-marine setting. An abrupt change from quartz-arenitic to feldspatholithic sandstone compositions marks the transition from Indian to Asian sediment provenance. The abrupt compositional change is accompanied by changes in U-Pb ages of detrital zircons diagnostic of a sediment provenance reversal, from Indian to Asian sources. The timing of the transition is bracketed between ~60 Ma and 58.5 ± 0.6 Ma by detrital zircon U-Pb ages and zircon U-Pb ages from a tuffaceous bed in the upper part of the section. In the context of a palinspastically restored regional paleogeographic framework, data from the Sangdanlin section combined with previously published data from the northern Tethyan Himalaya and the frontal Nepalese Lesser Himalaya and Subhimalaya suggest that a flexural wave migrated ~1300 km southward across what is now the Himalayan thrust belt from Paleocene time to the present.

DeCelles, P. G.; Kapp, P.; Gehrels, G. E.; Ding, L.

2014-05-01

311

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)

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 insitu 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.

Jyothibabu, R.; Vinayachandran, P. N.; Madhu, N. V.; Robin, R. S.; Karnan, C.; Jagadeesan, L.; Anjusha, A.

2015-03-01

312

Spatio-temporal spawning and larval dynamics of a zebra mussel (Dreissena polymorpha) population in a North Texas Reservoir: implications for invasions in the southern United States  

USGS Publications Warehouse

Zebra mussels were first observed in Texas in 2009 in a reservoir (Lake Texoma) on the Texas-Oklahoma border. In 2012, an established population was found in a near-by reservoir, Ray Roberts Lake, and in June 2013, settled mussels were detected in a third north Texas reservoir, Lake Lewisville. An established population was detected in Belton Lake in September 2013. With the exception of Louisiana, these occurrences in Texas mark the current southern extent of the range of this species in the United States. Previous studies indicate that zebra mussel populations could be affected by environmental conditions, especially increased temperatures and extreme droughts, which are characteristic of surface waters of the southern and southwestern United States. Data collected during the first three years (2010–12) of a long-term monitoring program were analyzed to determine if spatio-temporal zebra mussel spawning and larval dynamics were related to physicochemical water properties in Lake Texoma. Reproductive output of the local population was significantly related to water temperature and lake elevation. Estimated mean date of first spawn in Lake Texoma was approximately 1.5 months earlier and peak veliger densities were observed two months earlier than in Lake Erie. Annual maximum veliger density declined significantly during the study period (p < 0.0001). A population crash occurred as a result of thermal stress and variability of lake elevation. In summer 2011, water temperatures peaked at 34.3°C and lake elevation declined to the lowest level recorded during the previous 18 years, which resulted in desiccation of substantial numbers of settled mussels in littoral zones. Veliger spatial distributions were associated with physicochemical stratification characteristics. Veligers were observed in the deepest oxygenated water after lake stratification, which occurred in late spring. Results of this study indicate environmental conditions can influence variability of population sizes and spatial distributions of zebra mussels along the current southern frontier of their geographic range. Although the future population size trajectory and geographic range are uncertain, increased temperatures and intermittent, extreme droughts likely will affect spatio-temporal dynamics of established populations if zebra mussels spread farther into the southern and southwestern United States.

Churchill, Christopher John

2013-01-01

313

Impact of moisture flux convergence and soil moisture on precipitation: a case study for southern U.S. with implications for the globe  

NASA Astrophysics Data System (ADS)

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 U.S., a region with a strong humidity gradient and intense moisture fluxes. Experiments with the Weather Research and Forecasting (WRF) 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 exerts a stronger impact on precipitation in wetter regions, where the direct moisture inflow is large. Over transitional zones, the effect of soil moisture variations becomes important, mainly by changing precipitation efficiency. The direct moisture contribution from surface ET is relatively small over all areas. Analysis of global reanalysis data sets shows that similar conclusions apply to other land regions. 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 we analyzed, African Sahel is the only region where soil moisture has greater impact than MFC on precipitation.

Wei, J.; Su, H.; Yang, Z.

2013-12-01

314

Combined structural interventions for gender equality and livelihood security: a critical review of the evidence from southern and eastern Africa and the implications for young people  

PubMed Central

Background Young people in southern and eastern Africa remain disproportionately vulnerable to HIV with gender inequalities and livelihood insecurities being key drivers of this. Behavioural HIV prevention interventions have had weak outcomes and a new generation of structural interventions have emerged seeking to challenge the wider drivers of the HIV epidemic, including gender inequalities and livelihood insecurities. Methods We searched key academic data bases to identify interventions that simultaneously sought to strengthen people's livelihoods and transform gender relationships that had been evaluated in southern and eastern Africa. Our initial search identified 468 articles. We manually reviewed these and identified nine interventions that met our criteria for inclusion. Results We clustered the nine interventions into three groups: microfinance and gender empowerment interventions; supporting greater participation of women and girls in primary and secondary education; and gender empowerment and financial literacy interventions. We summarise the strengths and limitations of these interventions, with a particular focus on what lessons may be learnt for young people (18–24). Conclusions Our review identified three major lessons for structural interventions that sought to transform gender relationships and strengthen livelihoods: 1) interventions have a narrow conceptualisation of livelihoods, 2) there is limited involvement of men and boys in such interventions, 3) studies have typically been done in stable populations. We discuss what this means for future interventions that target young people through these methods. PMID:22713350

Gibbs, Andrew; Willan, Samantha; Misselhorn, Alison; Mangoma, Jaqualine

2012-01-01

315

Construction of Late Devonian Dundunshan arc in the Beishan orogen and its implication for tectonics of southern Central Asian Orogenic Belt  

NASA Astrophysics Data System (ADS)

The Beishan orogen, located in the southern Central Asian Orogenic Belt, was formed by subduction-accretionary processes in the Paleozoic, and so provides key constraints on the current international controversy regarding the duration of the orogenesis and the time of its termination and formation of the final suture. This paper concerns the tectonic setting, in the Beishan, of Devonian volcanic and sedimentary rocks that belong to the Dundunshan subduction-generated volcanic arc. The Dundunshan arc comprises metaluminous to weakly peraluminous, calc-alkaline andesites, dacites, rhyolites, porphyries and tuffs, which have Late Devonian U-Pb zircon ages of 368.8 ± 3.1 Ma and 370.9 ± 1.3 Ma. The rhyolites have an arc geochemical signature. The Dundunshan sediments are predominantly clastic sandstones, the trace element geochemical data of which indicate derivation from a rhyolitic source with variable degrees of weathering, suggesting an active tectonic provenance. The Dundunshan arc is situated on the southern side of the Huaniushan arc, which, according to current published data, was generated by northward subduction in the Early Paleozoic, and this was followed by the Dundunshan arc in the Late Devonian. It is likely that the northward-dipping subduction zone retreated southwards, giving rise to southward younging of the arcs. Our data provide important constraints on a better understanding of the growth of arcs that dominate the Altaid accretionary orogen.

Guo, Qianqian; Xiao, Wenjiao; Hou, Quanlin; Windley, Brian F.; Han, Chunming; Tian, Zhonghua; Song, Dongfang

2014-01-01

316

New c. 270 kyr strike-slip and uplift rates for the southern Alpine Fault and implications for the New Zealand plate boundary  

NASA Astrophysics Data System (ADS)

Along 100 km of the Alpine Fault, major valleys and glacial deposits can be matched across an 8000 m dextral offset. We use paleontologic and stratigraphic age constraints to date c. 270 ka marine sediments uplifted to 600 m elevation and overlying c. 270 ka glacial deposits related to the 8000 m dextral offset. These constraints yield a fault-proximal Australian plate uplift rate of 2.6 (-0.5/+0.4) mm/yr and an Alpine Fault dextral slip rate of 29.6 (-2.5/+4.5) mm/yr. Our rates resolve an apparent along-strike drop in strike-slip rate and instead support a relatively constant along-strike dextral slip rate of ˜28 mm/yr (˜80% of current Australian-Pacific plate boundary motion). We argue that the rate of dextral slip on the southern Alpine Fault has been relatively constant over the last ?3.5 myr, and that ductile fault processes may rate-limit the fault from accommodating a progressively higher percentage of plate boundary motion through time (i.e., the fault reached maturity long ago). The spatiotemporally constant strike-slip rate of the southern Alpine Fault and a previously published paleoseismic record of near-regular earthquake recurrence both characterize the Alpine Fault as a mature plate boundary fault zone that behaves in a constant way with behavior predictable over timescales of thousands and hundreds of thousands of years.

Barth, N. C.; Kulhanek, D. K.; Beu, A. G.; Murray-Wallace, C. V.; Hayward, B. W.; Mildenhall, D. C.; Lee, D. E.

2014-07-01

317

Geology, Geochemistry and Geochronology of the Upper Cretaceous high-K volcanics in the southern Part of the Eastern Pontides: Implications for Mesozoic Geodynamic Evolution of NE Turkey  

NASA Astrophysics Data System (ADS)

The Eastern Pontide Orogenic Belt is one of the most complex geodynamic settings in the Alpine-Mediterranean region. Its geodynamic evolution is very controversial due to lack of systematic, quantitative structural, geochemical and geochronological data. This belt is divided into three subgroups: northern, southern and axial zones, distinguished from north to south by different lithological units, facies changes and tectonic characteristics. Especially, the southern zone is very attractive with its numerous rock associations such as alaskan-type mafic-ultramafic intrusions, shoshonitic and ultrapotassic volcanics, adakitic magmatics, glaucophane-bearing gabbros, metamorphic and ultramafic massifes. This study focuses on the petrology, geotectonic setting and evidence for subduction polarity of the Upper Cretaceous shoshonitic and ultrapotassic volcanics exposed in the most southerly part of the eastern Pontide magmatic arc. Geological, geochemical and isotopic data indicate that there were two distinct cycles of high-K volcanic activity in the southern part of the eastern Pontide magmatic arc during the Late Cretaceous. The first cycle (Early Campanian), represented by shoshonitic trachyandesites and associated pyroclastics, containing high K2O (2.74-4.81 wt %) and Na2O (3.60-5.51 wt %), overlies the Middle-Cretaceous ophiolitic-olistostromal melange formed during the rifting stage of a back-arc basin (Neotethys). The second cycle of high-K volcanism is characterized by potassic or ultrapotassic analcime-bearing volcanics, erupted in a lagoonal environment during the Maastrichtian. Progressive shallowing of the basin indicates that Upper Cretaceous high-K volcanism developed during the final stage of pull-apart basin development in the southern zone of the eastern Pontides. These volcanic rocks, intercalated with continental detritus, are characterized by high Na2O (3.22-7.16 wt %) concentrated in secondary analcime crystals. Their K2O contents also range between 0.83 and 6.05 (wt %). Volcanic rocks belonging to both cycles have remarkable similarity in their trace and rare earth element concentrations and display variable enrichment in large ion lithophile elements (LILE), high field strength elements (HFSE), light rare earth elements (LREE) and heavy rare earth elements (HREE) with respect to primitive mantle and chondrite. Negative Nb, Ta, Zr, Hf and Ti anomalies are typical of subduction-related arc magmas. In addition, Nd-Sr and Pb isotope ratios of the investigated volcanics support that they are products of a similar mantle source. Undoubtedly, the existence of the subduction-related high-K volcanics in the southern part of the eastern Pontide magmatic arc is very important for interpretation of subduction polarity. Southward subduction of the Paleotethys oceanic crust during Mesozoic can be separated into two main stages. The first stage of southward subduction ended with slab break-off of the old and dense part of the Paleotethys oceanic crust during the Mid-Cretaceous. This process caused upwelling of the asthenospheric mantle and opening of the back-arc basins in the eastern Pontides. Middle Cretaceous olistostromal ophiolitic mélange formed on the transitional crust or on true oceanic crust restricted by deep spreading troughs of the pull-apart basins. Deformation of the deep-spreading troughs, in which the mélange formed, was initially extensional (drifting stage) but became increasingly compressional (infilling stage) as the strike-slip cycle was completed. Southward migration of the Upper Cretaceous volcanism in the eastern Pontides (arranged TH-CA in the north, CA-A in the south and shoshonitic-ultrapotassic in the far south) implies that the remaining undepleted part of Paleotethys oceanic crust continued to subduct southward. In addition, intense volcanic activity and emplacement of granite, gabbro and diorite intrusions in the northern part of the arc caused break-up of the Malm-Lower Cretaceous carbonate platform during the Upper Cretaceous.

Eyuboglu, Y.

2009-04-01

318

Petrogenesis of Cretaceous adakite-like intrusions of the Gangdese Plutonic Belt, southern Tibet: Implications for mid-ocean ridge subduction and crustal growth  

NASA Astrophysics Data System (ADS)

We have conducted a whole-rock geochemical, U-Pb zircon geochronological, and in situ zircon Hf-O isotopic compositional study of rocks in southern Tibet from the Langxian igneous suite (including a lamprophyre dyke, mafic enclaves, a granodiorite, and a two-mica granite) and the Nuri igneous suite (a quartz-diorite). U-Pb zircon dating indicates that the timing of crystallization of the mafic enclaves and host granodiorite of the Langxian suite are ca. 105 Ma and 102 Ma, respectively, that the Langxian lamprophyre dyke and the two-mica granite were emplaced at ca. 96 Ma and 80-76 Ma, respectively, and that the Nuri quartz-diorite was emplaced at ca. 95 Ma. With the exception of the lamprophyre dyke and mafic enclaves in the Langxian area, felsic rocks from the Langxian and Nuri igneous suites all show signs of a geochemical affinity with adakite-like rocks. The high Mg-numbers, high abundance of compatible elements, high ?Nd(t) (2.7 and 2.8) and ?18O (8.9 and 9.2‰) values, elevated zircon ?Hf(t) (11.0-17.0) values, and low 87Sr/86Sr(i) ratios (0.7040), collectively indicate that the Nuri adakite-like quartz-diorite was derived from partial melting of the low temperature altered Neo-Tethyan oceanic crust, and that these dioritic magmas subsequently interacted with peridotite as they rose upwards through the overlying mantle wedge. The observation of identical differentiation trends, similar whole-rock Sr-Nd and zircon Hf isotopic compositions, and consistently low (Dy/Yb)N ratios among the Langxian igneous suite rocks, indicates that the adakite-like granodiorite was produced by low-pressure fractional crystallization of precursor magmas now represented by the (relict) mafic enclaves. However, relatively high Al2O3 contents, low MgO, Cr and Ni contents, and low (La/Yb)N and (Dy/Yb)N values indicate that the two-mica granite was derived from partial melting of the southern Tibetan mafic lower crust in the absence of garnet, while isotopic data suggest that at least 70% of the magma source region was juvenile materials. Combined with the presence of HT (high temperature) charnockitic magmatism, HT granulite facies metamorphism, and large volumes of Late Cretaceous batholiths, the oceanic-slab-derived Nuri adakitic rocks indicate a substantial high heat flux in the Gangdese batholith belt during the Late Cretaceous, which may have been related to subduction of a Neo-Tethyan mid-ocean ridge system. According to this model, hot asthenosphere would rise up through the corresponding slab window, and come into direct contact with both the oceanic slab and the base of the overlying plate. This would cause melting of both the oceanic slab and the overlying plate by the addition of heat that was ultimately linked with peak magmatism and the significant growth and chemical differentiation of juvenile crust in southern Tibet during the Late Cretaceous (105-76 Ma). In addition, the petrogenesis of the Langxian adakite-like two-mica granite indicates that the southern Tibetan crust was still of normal thickness prior to the emplacement of these intrusions at ca. 76 Ma. This probably means that large parts of southern Tibet were not very highly elevated prior to the Indian-Asian collision.

Zheng, Yuan-chuan; Hou, Zeng-qian; Gong, Ying-li; Liang, Wei; Sun, Qing-Zhong; Zhang, Song; Fu, Qiang; Huang, Ke-Xian; Li, Qiu-Yun; Li, Wei

2014-03-01

319

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)

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 ?Nd(t) values ranging from -6.2 to - 1.3 and zircon ?Hf(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 ?Nd(t) values (- 16.1 to - 7.5) and zircon ?Hf(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.

Gao, Xin-Yu; Zhao, Tai-Ping; Bao, Zhi-Wei; Yang, Alexandra Yang

2014-10-01

320

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)

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.

Mcauliffe, L. J.; Dolan, J. F.; Hubbard, J.; Shaw, J. H.; Pratt, T. L.; Rhodes, E. J.

2013-12-01

321

Field geology, geochronology and geochemistry of mafic-ultramafic rocks from Alxa, China: Implications for Late Permian accretionary tectonics in the southern Altaids  

NASA Astrophysics Data System (ADS)

The time of termination of orogenesis for the southern Altaids has been controversial. Systematic investigations of field geology, geochronology and geochemistry on newly discriminated mafic-ultramafic rocks from northern Alxa in the southern Altaids were conducted to address the termination problem. The mafic-ultramafic rocks are located in the Bijiertai, Honggueryulin, and Qinggele areas, stretching from west to east for about 100 km. All rocks occur high-grade gneisses as tectonic lenses that are composed of peridotite, pyroxenite, gabbro, and serpentinite, most of which have undergone pronounced alteration, i.e., serpentinization and chloritization. Geochemically, the rocks are characterized by uniform compositional trends, i.e., with low SiO2-contents (42.51-52.21 wt.%) and alkalinity (Na2O + K2O) (0.01-5.45 wt.%, mostly less than 0.8 wt.%), and enrichments in MgO (7.37-43.36 wt.%), with Mg# = 52.75-91.87. As the rocks have been strongly altered and have a wide range of loss-on-ignition (LOI: 0.44-14.07 wt.%) values, they may have been subjected to considerable alteration by either seawater or metamorphic fluids. The REE and trace element patterns show a relatively fractionated trend with LILE enrichment and HFSE depletion, similar to that of T-MORB between N-MORB and E-MORB, indicating that the parental melt resulted from the partial melting of oceanic lithospheric mantle overprinted by fluid alteration of island-arc origin. The ultramafic rocks are relics derived from the magma after a large degree of partial melting of oceanic lithospheric mantle with superposed island arc processes under the influence of mid-ocean-ridge magmatism. LA-ICP MS U-Pb zircon ages of gabbros from three spots are 274 ± 3 Ma (MSWD = 0.35), 306 ± 3 Ma (MSWD = 0.49), 262 ± 5 Ma (MSWD = 1.2), respectively, representing the formation ages of the mafic-ultramafic rocks. Therefore, considering other previously published data, we suggest that the mafic-ultramafic rocks were products of south-dipping subduction, most probably with a slab window caused by ridge subduction, of the Paleo-Asian Ocean plate beneath the Alxa block in the Late Carboniferous to Late Permian before the Ocean completely closed. This sheds light on the controversial tectonic history of the southern Altaids and supports the concept that the termination of orogenesis was in the end-Permian to Triassic.

Feng, Jianyun; Xiao, Wenjiao; Windley, Brian; Han, Chunming; Wan, Bo; Zhang, Ji'en; Ao, Songjian; Zhang, Zhiyong; Lin, Lina

2013-12-01

322

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)

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.

Darin, M. H.; Dorsey, R. J.

2012-12-01

323

New paleomagnetic data from Late Neoproterozoic sedimentary successions in Southern Urals, Russia: implications for the Late Neoproterozoic paleogeography of the Iapetan realm  

NASA Astrophysics Data System (ADS)

We present the results of paleomagnetic study of Ediacaran sedimentary successions from the Southern Urals. The analysis of the sedimentary rocks of the Krivaya Luka, Kurgashlya and Bakeevo Formations reveal stable mid-temperature and high-temperature remanence components. Mid-temperature components were acquired during Devonian (Bakeevo Formation) and Late Carboniferous-Early Permian remagnetization events. The high-temperature components in Kurgashlya and Bakeevo Formations are interpreted to be primary, because they are supported by a positive conglomerate test (Bakeevo Formation) and magnetostratigraphic pattern (Kurgashlya Formation). The high-temperature component in the Krivaya Luka Formation is interpreted to be a Late Ediacaran overprint. Our new paleomagnetic poles together with some previously published Ediacaran poles from Baltica and Laurentia are used herein to produce a series of paleogeographic reconstructions of the opening of the Iapetus Ocean.

Lubnina, Natalia V.; Pisarevsky, Sergei A.; Puchkov, Victor N.; Kozlov, Vjacheslav I.; Sergeeva, Nina D.

2014-07-01

324

U-Cr-rich high Mg-Al granulites from Karimnagar Granulite Belt, India: implications for Neoarchean-Paleoproterozoic events in southern India  

NASA Astrophysics Data System (ADS)

High Mg-Al granulite occurs as enclave within granite gneisses at Karimnagar, southern India, and it contains coarse granoblastic aggregates of orthopyroxene and sapphirine with minor amount of cordierite, spinel and phlogopite. An important chemical characteristic of these minerals is their extremely high MgO content and the high Cr2O3 in sapphirine and spinel. Textural analysis shows sapphirine + orthopyroxene + cordierite as the peak-metamorphic assemblage that possibly evolved though the breakdown of a spinel-bearing assemblage. Cation exchange geothermometers involving orthopyroxene, sapphirine and spinel yield temperatures of 600-800 °C with a maximum of 860 °C implying an event of high temperature (HT) metamorphism. Pseudosection analysis in the FeO-MgO-Al2O3-SiO2 chemical system shows the stability of the peak- assemblage below 6.2 kbar. Subsequently, the rock underwent hydration and cooling with the appearance of phlogopite in the assemblage. Chromium enrichment is possibly inherited from the protolith and its presence presumably stabilized sapphirine and spinel below their high-temperature stability field. The recorded Rb-Sr age of ca. 2,500 Ma in host granite gneiss marks the upper age limit of HT metamorphism. Presence of patchy, lobate grains as well as veinlets of uraninite and brannerite is also a characteristic feature of the rock. Uranium mineralization took place during the post peak metamorphic stage, sulfide mineralization represented by tiny grains and veinlets of pyrite, millerite and pentlandite coincided with, and outlasted the uranium mineralization. The U-Th-Pb chemical ages of uraninite grains suggest ca. 2,200 ± 12 Ma for the age of uranium mineralization in the granulite. Based on the field relations, it is surmised that the granulite metamorphism in the study area is older than ca. 2,500 Ma and is comparable with an event in the other parts of Eastern Dharwar Craton. It can be conceived as a widespread event in southern India.

Sarbajna, Chanchal; Bose, Sankar; Rajagopalan, V.; Das, Kaushik; Som, Anjan; Paul, A. K.; Shivkumar, K.; Umamaheswar, K.; Chaki, Anjan

2013-08-01

325

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)

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 ?Hf(t) values mainly vary from -17.7 to +0.9 and TDMC ages mainly from 2301 to 1118 Ma. Whole rock ?Nd(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.

Gao, Xin-Yu; Zhao, Tai-Ping; Chen, Wei-Terry

2014-11-01

326

Geochronology and geochemistry of the Sangri Group Volcanic Rocks, Southern Lhasa Terrane: Implications for the early subduction history of the Neo-Tethys and Gangdese Magmatic Arc  

NASA Astrophysics Data System (ADS)

The Sangri Group volcanic rocks are distributed along the southern margin of the Lhasa Terrane on the northern side of the Indus-Yarlung Zangbo suture zone. This Group consists of the Mamuxia and Bima formations and has long been considered to be Late Jurassic to Early Cretaceous in age. In this paper, we report for the first time zircon LA-ICPMS U-Pb ages, whole-rock major and trace element geochemistry, as well as Sr-Nd isotope data of the Bima Formation volcanic rocks in the Sangri County, Tibet. Two samples collected from the Bima Formation volcanic rocks yield zircon U-Pb ages of 195 ± 3 Ma and 189 ± 3 Ma, respectively. These data suggest that the Bima Formation volcanic rocks formed during the Early Jurassic rather than the Late Jurassic-Early Cretaceous as previously reported. The volcanic rocks of the Bima Formation are dominantly composed of basalt and andesite that are enriched in LILEs and LREEs, but depleted in HFSEs, showing typical characteristics of arc volcanic rocks. They also show positive ?Nd (t) (+ 4.09 to + 7.02) values and low initial 87Sr/86Sr (0.7032 to 0.7050) ratios, similar to the MORB of the Indus-Yarlung Zangbo ophiolites, indicating that the Bima Formation volcanic rocks were derived from a depleted mantle wedge. The magmas subsequently experienced juvenile crust contamination and fractional crystallization during ascent. Geochemical features of magmas of the Bima Formation volcanic rocks are interpreted to be generated by the northward subduction of Neo-Tethys beneath the southern Lhasa Terrane as early as ~ 195 Ma. Coeval with a large volume of Late Triassic-Early Jurassic felsic intrusions within the Gangdese arc, the Gangdese magmatic arc is interpreted to be initiated at a juvenile continental margin during the Late Triassic-Early Jurassic, although a possible intra-oceanic arc setting cannot be excluded.

Kang, Zhi-Qiang; Xu, Ji-Feng; Wilde, Simon A.; Feng, Zuo-Hai; Chen, Jian-Lin; Wang, Bao-Di; Fu, Wen-Chun; Pan, Hui-Bin

2014-07-01

327

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)

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.

Hauksson, E.; Chi, W.; Shearer, P.

2003-12-01

328

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)

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.

Rivera, J. A.; Penalba, O. C.

2012-12-01

329

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)

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".

Dill, H. G.; Ludwig, R.-R.; Kathewera, A.; Mwenelupembe, J.

2005-06-01

330

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)

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.

Giacosa, R.; Zubia, M.; Sánchez, M.; Allard, J.

2010-12-01

331

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)

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.

Koehler, R. D.; Mann, P.; Brown, L. A.

2009-12-01

332

1.4 kyrs of flash flood events in the Southern European Alps: implications for extreme precipitation patterns and forcing over the north-western Mediterranean area  

NASA Astrophysics Data System (ADS)

Extreme precipitation events trigger flash floods causing large human and economic losses. Their frequency and/or intensity are expected to increase in the context of global warming, especially in the Mediterranean region. However, the relationship between such events and past climate change remains difficult to assess. Indeed, the stochastic nature of extreme event occurrence precludes the identification of trends. This is reinforced by a lack in long-term instrumental data. It is hence essential to reconstruct long-term geological records of intense events to extend documented records beyond the observational data. This will enable a better understanding of local to regional flood hazard patterns in the context of global warming and hence improve predictive models. In the framework of Pygmalion research program, a multiproxy investigation of the Lake Allos (2230 m a.s.l., Southern French Alps) sediment sequence revealed the presence of 160 flood-triggered interbedded layers within a 1400-long sequence. Owing to sedimentary and geochemical characteristics and the frequent occurrence, such deposits were interpreted as the result of high-energy sediment inputs during intense torrential floods (i.e. flash-floods), related to extreme precipitation events. Furthermore the significant relationship between the thickness and the basal grain size of the graded beds allowed using the thickness as a proxy of the flood intensity. Trough the comparison with local historic flood reconstructions over the last 400 years, we argue that these flash floods were mostly triggered by autumnal meso-scale intense precipitation events. Since the Medieval Climate Anomaly (MCA), the absence of major change in erosion processes and local vegetation dynamics linked to anthropogenic impact led us to interpret the Allos flood record as the proxy for the occurrence of such extreme precipitation events over the last millennium. The frequency of Allos flash-flood events appeared consistent with the general moisture, the hydrology of large rivers and temperature patterns of the south-western European region, i.e. a low flood activity during the warm/dry MCA and conversely during the cold/wet Little Ice Age (LIA). At a sub-centennial scale, a high variability of the flood frequency is superimposed to the general increase during the LIA and appeared in phase with solar maximum. Moreover peaks of flood frequency seem to be correlated with negative autumnal NAO phases, in agreement with previous paleoflood reconstructions of Mediterranean Spanish rivers. Finally the comparison of flood frequency patterns from north-western Mediterranean sites suggests a 50-150 years oscillation mode, probably related to a NAO-like pattern, in two main NW Mediterranean atmospheric circulation patterns triggering extreme precipitations either over the Southern Alps or the Cevennes-Vivarais region.

Wilhelm, B.; Arnaud, F.; Sabatier, P.; Crouzet, C.; Brisset, E.; Guiter, F.; Reyss, J. L.; Chaumillon, E.; Tachikawa, K.; Bard, E.; Delannoy, J. J.

2012-04-01

333

Habitat overlap between southern bluefin tuna and yellowfin tuna in the east coast longline fishery - implications for present and future spatial management  

NASA Astrophysics Data System (ADS)

Southern bluefin tuna (SBT) are presently a quota-managed species in the multi-species eastern Australian tuna and billfish longline fishery (ETBF). Capture of SBT is regulated by quota, as is access to regions likely to contain SBT. A habitat prediction model combining data from an ocean model and pop-up satellite archival tags is used to define habitat zones based on the probability of SBT occurrence. These habitat zones are used by fishery managers to restrict access by ETBF fishers to SBT habitat during a May-November management season. The zones display a distinct seasonal cycle driven by the seasonal southward expansion and northward contraction of the East Australia Current (EAC) and as a result access by fishers to particular ocean regions changes seasonally. This species also overlaps with the commercially valuable yellowfin tuna (YFT), thus, we modified the SBT model to generate YFT habitat predictions in order to investigate habitat overlap between SBT and YFT. There is seasonal variation in the overlap of the core habitat between these two species, with overlap early (May-Jul) in the management season and habitat separation occurring towards the end (Aug-Nov). The EAC is one of the fastest warming ocean regions in the southern hemisphere. To consider the future change in distribution of these two species compared to the present and to explore the potential impact on fishers and managers of the future, we use future ocean predictions from the CSIRO Bluelink ocean model for the year 2064 to generate habitat predictions. As the ocean warms on the east coast of Australia and the EAC extends southward, our model predicts the suitable habitat for SBT and YFT will move further south. There was an increase in the overlap of SBT and YFT habitat throughout the management season, due to regional variation of each species' habitat. These results illustrate that a management tradeoff exists between restricting fisher access to SBT habitat and allowing access to YFT habitat. We suggest that some options to address this tradeoff are possible by identifying the seasonal variability of the overlap.

Hartog, Jason R.; Hobday, Alistair J.; Matear, Richard; Feng, Ming

2011-03-01

334

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)

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 ?Nd(t) values, while gabbros exhibit relatively high (87Sr/86Sr)i and low ?Nd(t) values. Isotopic compositions of these mafic rocks display a mixed trend between depleted and enriched mantles. Meanwhile, differing ?Nd(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.

Zheng, Rongguo; Wu, Tairan; Zhang, Wen; Meng, Qingpeng; Zhang, Zhaoyu

2014-09-01

335

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)

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.

Weber, B.; Schaaf, P.; Valencia, V. A.; Lopez-Martinez, M.; Ortega-Gutierrez, F.

2007-05-01

336

A need for One Health approach – lessons learned from outbreaks of Rift Valley fever in Saudi Arabia and Sudan  

PubMed Central

Introduction Rift Valley fever (RVF) is an emerging viral zoonosis that impacts human and animal health. It is transmitted from animals to humans directly through exposure to blood, body fluids, or tissues of infected animals or via mosquito bites. The disease is endemic to Africa but has recently spread to Saudi Arabia and Yemen. Our aim was to compare two major outbreaks of RVF in Saudi Arabia (2000) and Sudan (2007) from a One Health perspective. Methods Using the terms ‘Saudi Arabia’, ‘Sudan’, and ‘RVF’, articles were identified by searching PubMed, Google Scholar, and web pages of international organizations as well as local sources in Saudi Arabia and Sudan. Results The outbreak in Saudi Arabia caused 883 human cases, with a case fatality rate of 14% and more than 40,000 dead sheep and goats. In Sudan, 698 human cases of RVF were recognized (case fatality, 31.5%), but no records of affected animals were available. The ecology and environment of the affected areas were similar with irrigation canals and excessive rains providing an attractive habitat for mosquito vectors to multiply. The outbreaks resulted in livestock trade bans leading to a vast economic impact on the animal market in the two countries. The surveillance system in Sudan showed a lack of data management and communication between the regional and federal health authorities, while in Saudi Arabia which is the stronger economy, better capacity and contingency plans resulted in efficient countermeasures. Studies of the epidemiology and vectors were also performed in Saudi Arabia, while in Sudan these issues were only partly studied. Conclusion We conclude that a One Health approach is the best option to mitigate outbreaks of RVF. Collaboration between veterinary, health, and environmental authorities both on national and regional levels is needed. PMID:24505511

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

2014-01-01

337

Accelerated removal of Sudan dye by Shewanella oneidensis MR-1 in the presence of quinones and humic acids.  

PubMed

Although there have been many studies on bacterial removal of soluble azo dyes, much less information is available for biological treatment of water-insoluble azo dyes. The few bacterial species capable of removing Sudan dye generally require a long time to remove low concentrations of insoluble dye particles. The present work examined the efficient removal of Sudan I by Shewanella oneidensis MR-1 in the presence of redox mediator. It was found that the microbially reduced anthraquinone-2,6-disulfonate (AQDS) could abiotically reduce Sudan I, indicating the feasibility of microbially-mediated reduction. The addition of 100 ?M AQDS and other different quinone compounds led to 4.3-54.7 % increase in removal efficiencies in 22 h. However, adding 5-hydroxy-1,4-naphthoquinone into the system inhibited Sudan I removal. The presence of 10, 50 and 100 ?M AQDS stimulated the removal efficiency in 10 h from 26.4 to 42.8, 54.9 and 64.0 %, respectively. The presence of 300 ?M AQDS resulted in an eightfold increase in initial removal rate from 0.19 to 1.52 mg h?¹ g?¹ cell biomass. A linear relationship was observed between the initial removal rates and AQDS concentrations (0-100 ?M). Comparison of Michaelis-Menten kinetic constants revealed the advantage of AQDS-mediated removal over direct reduction. Different species of humic acid could also stimulate the removal of Sudan I. Scanning electronic microscopy analysis confirmed the accelerated removal performance in the presence of AQDS. These results provide a potential method for the efficient removal of insoluble Sudan dye. PMID:23539152

Liu, Guangfei; Zhou, Jiti; Ji, Qiuyan; Wang, Jing; Jin, Ruofei; Lv, Hong

2013-09-01

338

analysis of pedestrian accident costs in Sudan using the willingness-to-pay method.  

PubMed

The willingness-to-pay (WTP) with contingent valuation (CV) method has been proven to be a valid tool for the valuation of non-market goods or socio-economic costs of road traffic accidents among communities in developed and developing countries. Research on accident costing tends to estimate the value of statistical life (VOSL) for all road users by providing a principle for the evaluation of road safety interventions in cost-benefit analysis. As in many other developing countries, the economic loss of traffic accidents in Sudan is noticeable; however, analytical research to estimate the magnitude and impact of that loss is lacking. Reports have shown that pedestrians account for more than 40% of the total number of fatalities. In this study, the WTP-CV approach was used to determine the amount of money that pedestrians in Sudan are willing to pay to reduce the risk of their own death. The impact of the socioeconomic factors, risk levels, and walking behaviors of pedestrians on their WTP for fatality risk reduction was also evaluated. Data were collected from two cities-Khartoum and Nyala-using a survey questionnaire that included 1400 respondents. The WTP-CV Payment Card Questionnaire was designed to ensure that Sudan pedestrians can easily determine the amount of money that would be required to reduce the fatality risk from a pedestrian-related accident. The analysis results show that the estimated VOSL for Sudanese pedestrians ranges from US$0.019 to US$0.101 million. In addition, the willingness-to-pay by Sudanese pedestrians to reduce their fatality risk tends to increase with age, household income, educational level, safety perception, and average time spent on social activities with family and community. PMID:25794921

Mofadal, Adam I A; Kanitpong, Kunnawee; Jiwattanakulpaisarn, Piyapong

2015-05-01

339

Reconstructing the southern South China Sea upper water column structure since the Last Glacial Maximum: Implications for the East Asian winter monsoon development  

NASA Astrophysics Data System (ADS)

Upper water column dynamics in the southern South China Sea were reconstructed in order to track changes in the activity of the East Asian winter monsoon (EAWM) since the Last Glacial Maximum. We used the difference in the stable oxygen isotopes (??18O) and Mg/Ca-based temperatures (?T) of surface-dwelling (G. ruber) and thermocline-dwelling (P. obliquiloculata) planktonic foraminifera and the temperature difference between alkenone- and P. obliquiloculata Mg/Ca-based temperatures to estimate the upper ocean thermal gradient at International Marine Past Global Change Study (IMAGES) core MD01-2390. Estimates of the upper ocean thermal gradient were used to reconstruct mixed layer dynamics. We find that our ??18O estimates are biased by changes in salinity and, thus, do not display a true upper ocean thermal gradient. The ?T of G. ruber and P. obliquiloculata as well as the alkenone and P. obliquiloculata suggest increased surface water mixing during the late glacial, likely due to enhanced EAWM winds. Surface water mixing was weaker during the late Holocene, indicating a weaker influence of winter monsoon winds. The weakest winter monsoon activity occurred between 6.5 ka and 2.5 ka. Inferred EAWM changes since the Last Glacial Maximum coincide with EAWM changes as recorded in Chinese loess sediments. We find that the intensity of the EAWM and the East Asian summer monsoon show an inverse behavior during the last glacial and deglaciation but covaried during the middle to late Holocene.

Steinke, Stephan; Mohtadi, Mahyar; Groeneveld, Jeroen; Lin, Li-Chuan; Löwemark, Ludvig; Chen, Min-Te; Rendle-Bühring, Rebecca

2010-06-01

340

Geomorphic assessment of late Quarternary volcanism in the Yucca Mountain area, southern Nevada: Implication for the proposed high-level radiocative waste repository  

SciTech Connect

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.

Wells, S.G.; McFadden, L.D.; Renault, C.E. [Univ. of New Mexico, Albuquerque, NM (USA)] [Univ. of New Mexico, Albuquerque, NM (USA); Crowe, B.M. [Los Alamos Yucca Mountain Project Office, Las Vegas, NV (USA)] [Los Alamos Yucca Mountain Project Office, Las Vegas, NV (USA)

1990-06-01

341

Geomorphic assessment of late Quaternary volcanism in the Yucca Mountain area, southern Nevada: Implications for the proposed high-level radioactive waste repository  

SciTech Connect

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.

Wells, S.G.; McFadden, L.D.; Renault, C.E. [Univ. of New Mexico, Albuquerque (USA); Crowe, B.M. [Los Alamos Yucca Mountain Project Office, Las Vegas NV (USA)

1991-03-01

342

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

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

Ahmad, Zulfiqar; Akhter, Gulraiz; Ashraf, Arshad; Fryar, Alan

2010-11-01

343

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)

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.

Raikes, S. A.

1978-01-01

344

Risk maps for the presence and absence of Phlebotomus perniciosus in an endemic area of leishmaniasis in southern Spain: implications for the control of the disease.  

PubMed

The aim of this study was to construct risk maps for the presence of the dominant Leishmania infantum vector, P. perniciosus, and check its usefulness (a) to predict the risk of canine leishmaniasis and (b) to define effective leishmaniasis control measures. We obtained data for the presence/absence of P. perniciosus at 167 sampling sites in southern Spain, from which we also took a series of ecological and climate-related data. The probability of P. perniciosus presence was estimated as a function of these environmental variables and generated spatial risk maps. Altitude, land use and drainage hole features (with or without PVC piping) were retained as the only predictors for the distribution of this vector species. Drainage hole features in retaining walls, with or without PVC piping, produce significant variations in the probability of P. perniciosus presence, varying from 2·3 to 91·8% if PVC piping is absent and from 0·4 to 66·5% if all holes have PVC piping. It was concluded that the use of PVC piping in drainage holes could help to reduce leishmaniasis transmission. PMID:21854702

Barón, S D; Morillas-Márquez, F; Morales-Yuste, M; Díaz-Sáez, V; Irigaray, C; Martín-Sánchez, J

2011-09-01

345

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

[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.

Bjoerkum, P.A. (Statoil, Stavanger (Norway)); Walderhaug, O. (Rogaland Research, Stavanger (Norway))

1993-07-01

346

Factors affecting competitive dominance of rainbow trout over brook trout in southern Appalachian streams: Implications of an individual-based model  

SciTech Connect

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.

Clark, M.E. [Univ. of Tennessee, Knoxville, TN (United States)] [Univ. of Tennessee, Knoxville, TN (United States); Rose, K.A. [Oak Ridge National Lab., TN (United States)] [Oak Ridge National Lab., TN (United States)

1997-01-01

347

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

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.

Critelli, S. [Consiglio Nazionale delle Ricerche, Roges di Rende (Italy). Istituto di Ricerca per la Protezione Idrogeologica nell`Italia Meridionale ed Insulare; Rumelhart, P.E.; Ingersoll, R.V. [Univ. of California, Los Angeles, CA (United States). Dept. of Earth and Space Sciences

1995-10-02

348

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

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.

Jiang, Shijun; Wise, Sherwood W., Jr.

2007-01-01

349

Relationship of the sickle cell gene to the ethnic and geographic groups populating the Sudan.  

PubMed

The presence of a geographical pattern in the distribution of the sickle cell gene (S gene) and its association with malaria is well documented. To study the distribution of the S gene among various ethnic and linguistic groups in the Sudan we analyzed a hospital-based sample of 189 sickle cell anemia (SCA) patients who reported to the Khartoum Teaching Hospital between June 1996 and March 2000 and 118 controls with other complaints, against their ethnic and linguistic affiliations and geographic origin. Electrophoresis for hemoglobin S and sickling tests were carried out on all patients and controls as a prerequisite for inclusion. The majority of patients (93.7%) belonged to families of single ethnic descent, indicating the high degree of within-group marriages and thus the higher risk of augmenting the gene. SCA was found to be predominant among the Afro-Asiatic-speaking groups (68.4%) including nomadic groups of Arab and non- Arab descent that migrated to the Sudan in various historical epochs. Those patients clustered in western Sudan (Kordofan and Darfur) from where 73% of all cases originate. The proportion of patients reporting from other geographic areas like the south (3.1%), which is primarily inhabited by Nilo-Saharan-speaking groups (19% of the whole sample) who populated the country in previous times, is disproportionate to their total population in the country (chi(2) = 71.6; p = 0.0001). Analysis of the haplotypes associated with the S gene indicated that the most abundant haplotypes are the Cameroon, Benin, Bantu and Senegal haplotypes, respectively. No relationship was seen between haplotypes and the various hematological parameters in the sub-sample analyzed for such association. These results provide an insight into the distribution of the sickle cell gene in the Sudan, and highlight the strong link of the middle Nile Valley with West Africa through the open plateau of the Sahel and the nomadic cattle herders and also probably the relatively young age of the S gene. PMID:16612062

Mohammed, Abdelrahim O; Attalla, Bekhieta; Bashir, Fathya M K; Ahmed, Fatima E; El Hassan, Ahmed M; Ibnauf, Gafar; Jiang, Weiying; Cavalli-Sforza, Luigi L; Karrar, Zein Al Abdin; Ibrahim, Muntaser E

2006-01-01

350

Neoproterozoic chromite-bearing high-Mg diorites in the western part of the Jiangnan orogen, southern China: Geochemistry, petrogenesis and tectonic implications  

NASA Astrophysics Data System (ADS)

High-Mg diorites were discovered in the southern part of the ca. 830 Ma Dongma Pluton, northern Guangxi Province of southern China. The diorites (SiO2 = 59-65 wt%) are characterized by high MgO (6.7-8.9 wt%) contents and Mg-number [Mg# = 100 × Mg/(Mg + Fe)] (69-73), in contrary to the associated medium-Mg (MgO = 3.4-3.8 wt%, Mg# = 59-63) granodiorites in the Dongma main body and the low-Mg (MgO = 1.4-1.9 wt%, Mg# = 46-51) granodiorites in the Bendong Pluton to the north. Moreover, the high-Mg diorites show surprisingly high Cr (595-640 ppm) and Ni (171-194 ppm) concentrations, which are beyond the ranges of most coeval mafic rocks in the study area. Correspondingly, chromite crystals were separated from the high-Mg diorites and some of the medium-Mg granodiorites, and they show high Cr# [100 × Cr/(Cr + Al)] (average of 75), but low Mg# (0.34-2.51) and low Fe3 +. The decoupling of Cr# and Mg# and the existence of quartz + apatite mineral inclusion in chromites suggest Mg-Fe exchange that may be facilitated by the disequilibrium resulted from magma mixing. The high-Mg diorites show low La/Yb (6.8-8.5) and Sr/Y (2.1-3.1) ratios, significant negative anomalies of Nb and Ti and positive anomaly of Pb, resembling the Setouchi high-Mg andesites, despite of their relatively low Sr (71-100 ppm). All of the studied diorites and granodiorites show enriched Nd isotope compositions, with ?Nd(t) values (- 3.2 to - 5.9) a bit higher than some of the associated mafic rocks. Some of the high-Mg diorites show whole-rock ?Hf(t) (- 6.0 to - 6.2) coupled with Nd isotopes, similar to the associated mafic-ultramafic rocks in northern Guangxi, suggesting the metasomatism by melts of subducting sediments in the mantle source. Whereas, others show decoupled Nd-Hf isotopes that are similar to the medium- and low-Mg granodiorites [?Hf(t) = - 1.8 to + 0.05], probably indicating the late magma mixing with granitic magmas at a crustal level for the dioritic magmas. We propose a two-stage model for the petrogenesis of the high-Mg diorites: 1) the mantle source was firstly metasomatized by melts from partial melting of subducting terrigenous sediments to form the enriched Nd-Hf isotopic characteristics; and then 2) the mantle-derived high-Mg mafic melts mixed with the crust-derived low-Mg granitic melts to form the high-Mg diorites and medium-Mg granodiorites. The occurrence of high-Mg diorites implies the existence of Neoproterozoic subduction-related metasomatism in the western part of the Jiangnan orogen.

Chen, Xin; Wang, Di; Wang, Xiao-Lei; Gao, Jian-Feng; Shu, Xu-Jie; Zhou, Jin-Cheng; Qi, Liang

2014-07-01

351

First reconstruction of last millennium flooding activity on Kerguelen archipelago (50°S, sub-Antarctic Indian Ocean) from Lake Armor sediment: implications for southern hemisphere cyclonic circulation changes  

NASA Astrophysics Data System (ADS)

Subantarctic Indian Ocean, above 50°S, is one the places in the world where past atmospheric circulation patterns remain completely unknown. This is an important lack in scientific knowledge of past climate changes as this region is one of the key places of the climate machine. In particular, we do not know the impact of Holocene climate variability on extreme south cyclonic circulation. Lake Armor is a fjord-type lake, 98m maximum depth, located on the eastern edge of Kerguelen mainland central plateau. A first reconnaissance survey, including seismic imaging and short cores retrieving, was led here in November 2006. Seismic and bathymetric data reveal the existence of two depocentres submitted to river inputs (Heirman et al., 2007 ; Arnaud et al., 2007). The southern one is submitted to strong underwater currents and is not suited for paleoclimate reconstruction. On the contrary, the northern one exhibits finely stratified Holocene deposits which were cored in the aim of reconstructing the evolution of river floods on Kerguelen archipelago. We led on the retrieved short cores a high resolution sedimentological study, including micro-grainsize, colour, physical properties (Geotek multi-track sensor), and geochemistry (XRF core scanning, major and trace elemental composition, infrared spectrometry). In the case of lake sediments in which detrital inputs are diluted by an autochthonous biogenic fraction, such an approach permits a high resolution reconstruction of flood history (Arnaud et al., 2005; Arnaud, 2005), taking account of both sediment source and river activity evolutions. Using an XRF core scanner, we established high resolution geochemical profiles on a short 14C-dated core, spanning the last 1200 years. We here interpret the Si/Rb ratio as an indicator of biogenic silica abundance, in opposition to Rubidium-bearing detrital inputs. We hence evidenced a series of high and low terrigenous inputs, corresponding to high and low flooding activity, respectively. Our results were compared with the only available climate-related information for Late Holocene on Kerguelen archipelago: a series of two 14C ages interpreted as evidences of glacier retreat (Frénot et al., 1997). Both records match together, as the 1100-1350 AD minima of flood activity corresponds to the younger age of glacier retreat. We hence evidence three periods of wetter conditions at ca. 800-1100, 1350-1750, 1880-1940 AD, which are interpreted as periods of enhanced cyclonic circulation, compared to the present-day situation. Those results show the potential of Lake Armor sediments to establish the first Holocene palaeohydrological record in southern Indian Ocean. References Arnaud et al., 2005, The Holocene 15, 420-428 Arnaud, 2005, Jour. Of Palaeolim. 34, 519-52 Arnaud et al., 2007, ILIC congress Frénot et al., 1997, CRAS 320, 567-573. Heirman et al., 2007, ILIC congress

Arnaud, F.; Révillon, S.; Poulenard, J.; Boone, D.; Heirman, K.

2009-04-01

352

Evolving transpressional strain fields along the San Andreas fault in southern California: implications for fault branching, fault dip segmentation and strain partitioning  

NASA Astrophysics Data System (ADS)

The San Andreas fault in southern California records only few large-magnitude earthquakes in historic time, and the recent activity is confined primarily on irregular and discontinuous strike-slip and thrust fault strands at shallow depths of ~5-20 km. Despite this fact, slip along the San Andreas fault is calculated to c. 35 mm/yr based on c.160 km total right lateral displacement for the southern segment of the fault in the last c. 8 Ma. Field observations also reveal complex fault strands and multiple events of deformation. The presently diffuse high-magnitude crustal movements may be explained by the deformation being largely distributed along more gently dipping reverse faults in fold-thrust belts, in contrast to regions to the north where deformation is less partitioned and localized to narrow strike-slip fault zones. In the Mecca Hills of the Salton trough transpressional deformation of an uplifted segment of the San Andreas fault in the last ca. 4.0 My is expressed by very complex fault-oblique and fault-parallel (en echelon) folding, and zones of uplift (fold-thrust belts), basement-involved reverse and strike-slip faults and accompanying multiple and pervasive cataclasis and conjugate fracturing of Miocene to Pleistocene sedimentary strata. Our structural analysis of the Mecca Hills addresses the kinematic nature of the San Andreas fault and mechanisms of uplift and strain-stress distribution along bent fault strands. The San Andreas fault and subsidiary faults define a wide spectrum of kinematic styles, from steep localized strike-slip faults, to moderate dipping faults related to oblique en echelon folds, and gently dipping faults distributed in fold-thrust belt domains. Therefore, the San Andreas fault is not a through-going, steep strike-slip crustal structure, which is commonly the basis for crustal modeling and earthquake rupture models. The fault trace was steep initially, but was later multiphase deformed/modified by oblique en echelon folding, renewed strike-slip movements and contractile fold-thrust belt structures. Notably, the strike-slip movements on the San Andreas fault were transformed outward into the surrounding rocks as oblique-reverse faults to link up with the subsidiary Skeleton Canyon fault in the Mecca Hills. Instead of a classic flower structure model for this transpressional uplift, the San Andreas fault strands were segmented into domains that record; (i) early strike-slip motion, (ii) later oblique shortening with distributed deformation (en echelon fold domains), followed by (iii) localized fault-parallel deformation (strike-slip) and (iv) superposed out-of-sequence faulting and fault-normal, partitioned deformation (fold-thrust belt domains). These results contribute well to the question if spatial and temporal fold-fault branching and migration patterns evolving along non-vertical strike-slip fault segments can play a role in the localization of earthquakes along the San Andreas fault.

Bergh, Steffen; Sylvester, Arthur; Damte, Alula; Indrevær, Kjetil

2014-05-01

353

Petrology and geochemistry of primitive lower oceanic crust from Pito Deep: Implications for the accretion of the lower crust at the Southern East Pacific Rise  

USGS Publications Warehouse

A suite of samples collected from the uppermost part of the plutonic section of the oceanic crust formed at the southern East Pacific Rise and exposed at the Pito Deep has been examined. These rocks were sampled in situ by ROV and lie beneath a complete upper crustal section providing geological context. This is only the second area (after the Hess Deep) in which a substantial depth into the plutonic complex formed at the East Pacific Rise has been sampled in situ and reveals significant spatial heterogeneity in the plutonic complex. In contrast to the uppermost plutonic rocks at Hess Deep, the rocks studied here are generally primitive with olivine forsterite contents mainly between 85 and 88 and including many troctolites. The melt that the majority of the samples crystallized from was aggregated normal mid-ocean ridge basalt (MORB). Despite this high Mg# clinopyroxene is common despite model predictions that clinopyroxene should not reach the liquidus early during low-pressure crystallization of MORB. Stochastic modeling of melt crystallisation at various levels in the crust suggests that it is unlikely that a significant melt mass crystallized in the deeper crust (for example in sills) because this would lead to more evolved shallow level plutonic rocks. Similar to the upper plutonic section at Hess Deep, and in the Oman ophiolite, many samples show a steeply dipping, axis-parallel, magmatic fabric. This suggests that vertical magmatic flow is an important process in the upper part of the seismic low velocity zone beneath fast-spreading ridges. We suggest that both temporal and spatial (along-axis) variability in the magmatic and hydrothermal systems can explain the differences observed between the Hess Deep and Pito Deep plutonics. ?? Springer-Verlag 2007.

Perk, N.W.; Coogan, L.A.; Karson, J.A.; Klein, E.M.; Hanna, H.D.

2007-01-01

354

Cyclostratigraphy of an orbitally-driven Tithonian-Valanginian carbonate ramp succession, Southern Mendoza, Argentina: Implications for the Jurassic-Cretaceous boundary in the Neuquén Basin  

NASA Astrophysics Data System (ADS)

Detailed sedimentological, sequence stratigraphical and cyclostratigraphical analyses have been made from four lower Tithonian-lower Valanginian sections of the Vaca Muerta Formation, exposed in the southern Mendoza area of the Neuquén Basin, Argentina. The Vaca Muerta Formation is characterized by decimetre-scale rhythmic alternations of marls, shales and limestones, and consists of five facies associations, which reflect different paleoenvironmental conditions: basin to restricted outer ramp, outer ramp, and middle ramp. Vertical organization within the Vaca Muerta Formation shows a well-ordered hierarchy of cycles, where elementary cycles, bundles and superbundles with frequencies within the Milankovitch band have been recognized. According to biostratigraphic data, elementary cycles have a periodicity of ~ 20 ky, which correlates with the precession cycle of Earth's axis. Spectral analysis based on series of cycle thickness allows us to identify frequencies of about 400 ky and 90-120 ky, which we interpret as the modulation of the precessional cycle by the Earth's orbital eccentricity. Cycles are probably driven by variations in carbonate exportation, as fluctuations in shallow-water carbonate production involve modifications in carbonate basinward exportation. Cyclostratigraphic data allowed us to build a floating orbital scale for the Tithonian-lower Valanginian interval in the Neuquén Basin. Correlation between studied sections allowed us to recognize a discontinuity between the Substeueroceras koeneni and Argentiniceras noduliferum ammonite zones in the Malargüe Anticline area. Orbital calibration of these sections is consistent with Riccardi's biostratigraphic scheme, wich place the Jurassic-Cretaceous boundary within the Substeueroceras koeneni ammonite Zone. On the other hand, the base of the Vaca Muerta Formation (Virgatosphinctes mendozanus ammonite Zone) would be probably placed in the base of the middle Tithonian rather than the lower Tithonian, which is also consistent with our preliminary palaeomagnetic data.

Kietzmann, Diego A.; Palma, Ricardo M.; Iglesia Llanos, Maria Paula

2015-01-01

355

The age of the Chuangde Formation in Kangmar, southern Tibet of China: Implications for the origin of Cretaceous oceanic red beds (CORBs) in the northern Tethyan Himalaya  

NASA Astrophysics Data System (ADS)

The Chuangde Formation in the northern Tethyan Himalaya consists of the Upper Cretaceous oceanic red beds (CORBs). Due to the structural complexity and poor fossil preservation, the age of this unit remains an issue. In one interpretation, the age of the Chuangde Formation in the eastern Tethyan Himalaya is significantly older than in the western Tethyan Himalaya, suggesting that the formation of CORBs in the Late Cretaceous Tethys ocean may have been triggered by the ocean circulation pattern change in response to the changes associated with the collision between Indian and Asian plates. New foraminiferal biostratigraphic data from a well-preserved and fossil-rich section in Kangmar, southern Tibet, China, reveal that the Chuangde Formation in the eastern Tethyan Himalaya has an age from Early Campanian to Maastrichtian. Fossil assemblages from this section allow its correlation with other CORB-bearing sections and argue against the age discrepancy of CORBs between the eastern and western parts of the northern Tethyan Himalaya. Biostratigraphic correlation and paleogeographic reconstruction indicates that the CORBs in the Tethyan Himalaya are restricted to the slope and basinal environments but they are entirely missing in the shelf environments including the shelf margin. The similar thicknesses (and therefore potentially similar sedimentation rates) of time-equivalent units between shelf and slope/basinal sections argues against the formation of CORBs in the Tethyan Himalaya by transportation of terrigenous iron into a sediment-starved ocean. The lack of CORBs in shelf environments and the widespread occurrence CORBs in slope/basinal environments suggest that the CORBs were likely formed by oxidation of reduced iron in the upper ocean water column close to the chemocline rather than in oxic bottom waters.

Li, Guobiao; Jiang, Ganqing; Wan, Xiaoqiao

2011-03-01

356

Stable isotope composition of suspended particulate organic matter in twenty reservoirs from Guangdong, southern China: implications for pelagic carbon and nitrogen cycling.  

PubMed

We studied seasonal variations in the carbon and nitrogen stable isotopes (?(13)C and ?(15)N) of particulate organic matter (POM) in the surface water of 20 man-made reservoirs in southern China during March, August and December 2010. These reservoirs are located from subtropical to tropical region, varied in trophic states and were influenced by several types of human activities. The geomorphometric and biogeochemical gradients in tropical/subtropical regions are complicated and poorly understood because of low variation in temperature and high variation in hydrological processes. The POM samples were collected from all the reservoirs to assess the seasonal variation patterns of ?(13)CPOM and ?(15)NPOM. Variation in ?(13)CPOM followed seasonal thermal and hydrological cycles. By contrast, ?(15)NPOM did not seasonally differ, which may have been complicated by phytoplankton assimilation of N originating in agricultural waste entering the reservoirs and of atmospheric nitrogen during the wet season as well as an increased relative contribution of animal waste in the reservoirs in the dry season. Within each sampling period, nutrient availability is more important than thermal and solar radiation inputs in the summer, and these physical drivers are more important during the dry and cold winter month in controlling ?(13)CPOM and ?(15)NPOM. On an annual basis, trophic states (total P, total N and chlorophyll a) are the primary drivers for the changes in both ?(13)CPOM and ?(15)NPOM across reservoirs. When the seasonal effect is removed using annual averages from each reservoir, we found that latitude, trophic states, pH, rainfall, water temperature, reservoir age, catchment area to reservoir area (CA:RA) ratio and together explained about 80% of the variance in both ?(13)CPOM and ?(15)NPOM. Our findings also suggest that the trend of ?(15)NPOM is less predictable than ?(13)CPOM. The consistent (15)N depletion and enrichment of POM in different reservoirs point to the importance of different anthropogenic sources of nitrogen in the reservoirs. PMID:23726697

Hou, Wei; Gu, Binhe; Lin, Qiuqi; Gu, Jiguang; Han, Bo-Ping

2013-07-01

357

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

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

Holden, Anna R; Koch, Jonathan B; Griswold, Terry; Erwin, Diane M; Hall, Justin

2014-01-01

358

Age and composition of Archean crystalline rocks from the southern Madison Range, Montana. Implications for crustal evolution in the Wyoming craton  

SciTech Connect

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.

Mueller, P.A.; Shuster, R.D. (Univ. of Florida, Gainesville (United States)); Wooden, J.L. (Geological Survey, Menlo Park, CA (United States)); Erslev, E.A. (Colorado State Univ., Fort Collins (United States)); Bowes, D.R. (Glasgow Univ. (United Kingdom))

1993-04-01

359

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

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.

Langenheim, V.E.; Powell, R.E.

2009-01-01

360

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

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

Holden, Anna R.; Koch, Jonathan B.; Griswold, Terry; Erwin, Diane M.; Hall, Justin

2014-01-01

361

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)

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.

Rich, Julie

2013-02-01

362

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)

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 (Borojevi? Šoštari? et al., 2012) and the Mid Bosnian Schist Mountains (Pami? 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 Borojevi? Šoštari?, 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. Ili?, 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. P

Neubauer, Franz; Heberer, Bianca; Genser, Johann; Friedl, Getrude

2014-05-01

363

Petrology and mineral equilibrium modeling of incipient charnockite from the Trivandrum Granulite Block, southern India: implications for granulite formation in a Gondwana fragment  

NASA Astrophysics Data System (ADS)

The Southern Granulite Terrane (SGT) in India is known for its classic exposures of regionally metamorphosed granulite-facies rocks formed during the collisional orogeny related to the amalgamation of Gondwana supercontinent. The SGT is composed of a collage of Proterozoic crustal blocks dissected by large Late Neoproterozoic shear/suture zones. The Trivandrum Granulite Block (TGB) is comprises dominantly metasedimentary sequence with khondalites, leptynites and charnockites with subordinate quartzite, mafic granulite, calc-silicate rocks, and meta-ultramafic rocks. The TGB is known as one of the classic examples for the spectacular development of 'incipient charnockites' within orthopyroxene-free felsic gneisses as exposed in several quarry sections in the states of Kerala and Tamil Nadu. The charnockite-forming process in the TGB is considered to have been triggered by the infiltration of CO2-rich anhydrous fluids along structural pathways within upper amphibolite facies gneisses, resulting in the lowering of water activity and stabilization of orthopyroxene through the breakdown of biotite. However, no quantitative study on the stability of charnockitic mineral assemblage using mineral equilibrium modeling approach has been done so far. In this study, we report a new occurrence of incipient charnockite from Mavadi in the TGB and discuss the petrogenesis of granulite formation in an arrested stage on the basis of petrography, geothermobarometry, and mineral equilibrium modeling. In Mavadi, patches and lenses of charnockite (Kfs + Qtz + Pl + Bt + Grt + Opx + Ilm + Mag) of about 30 to 120 cm in length occur within Opx-free Grt-Bt gneiss (Kfs + Qtz + Pl + Bt + Grt + Ilm) host rocks. The application of mineral equilibrium modeling on charnockite assemblage in NCKFMASHTO system to constrain the conditions of charnockitization defines a P - T range of 800° C at 4.5 kbar to 850° C at 8.5 kbar, which is broadly consistent with the results from the conventional geothermobarometry (810-880° C at 7.7-8.0 kbar) on these rocks. The P - T conditions are lower than the inferred peak metamorphic conditions from the ultrahigh-temperature granulites of the study area (T >900° C), which might suggest heterogeneity in peak P - T conditions within this crustal block in relation to local buffering of metamorphic temperature by Opx-Bt-Kfs-Qtz assemblage. The result of T versus mole H2O (M(H2O)) modeling demonstrated that Opx-free assemblage in Grt-Bt gneiss is stable at M(H2O) = 0.3 to 1.5 mol.%, and orthopyroxene occurs as a stable mineral at M(H2O)

Endo, T.; Tsunogae, T.; Santosh, M.

2012-04-01

364

Multiple mineralization events at the Jiru porphyry copper deposit, southern Tibet: Implications for Eocene and Miocene magma sources and resource potential  

NASA Astrophysics Data System (ADS)

The Jiru porphyry copper deposit in the Gangdese Porphyry Copper Belt (GPCB) is hosted by monzogranite and monzogranite porphyry with SHRIMP U-Pb ages of 48.6 ± 0.8 Ma and 16.0 ± 0.4 Ma, respectively. Rhenium-Os ages of molybdenite from the monzogranite and monzogranite porphyry are 44.9 ± 2.6 Ma and 15.2 ± 0.4 Ma, slightly younger than ages of the host rocks, respectively. These geochronological data indicate that there are two mineralization events at the Jiru deposit, in contrast to other porphyry deposits in the eastern part of the GPCB that are only Miocene in age. The Eocene monzogranite is characterized by high SiO2 (63.0-71.4%) and K2O (3.7-5.9%), enrichment in LILEs, depletion in Nb, Ta, and Ti, moderate negative Eu anomalies (?Eu = 0.55-0.94), and relatively low Sr/Y (14-39) and (La/Yb)n (9-20) ratios. It also has young ?Nd(t) values (-0.43 to -0.25), low initial 87Sr/86Sr ratios (0.7044-0.7048), and young depleted-mantle model ages TDM (742-821 Ma), compared to Eocene melts derived from mature continental crust in the central Lhasa subterrane. These geochemical features suggest that the Jiru monzogranite was most likely derived from the hydrated asthenospheric mantle wedge with involvement of subducted sediments related to the Neo-Tethyan oceanic slab breakoff. The Miocene monzogranite porphyry contains hydrous phenocryst phases (hornblende and biotite) and displays LREE-enrichment patterns, with high Sr/Y (131-183) and (La/Yb)n (22-72) ratios, and weak or absent Eu anomalies. The porphyry has slightly negative ?Nd(t) values (-3.8 to -3.5), low initial 87Sr/86Sr ratios (0.7057-0.7058), and young TDM (952-974 Ma). The Miocene porphyry is likely the product of remelting of the stalled Neo-Tethyan oceanic slab, with input from the lower crust during the convective removal of thickened lithosphere below southern Tibet. Recognition of the Eocene magmatic-hydrothermal ore-forming event indicates a newly recognized potential for copper resources of that age in the eastern GPCB.

Zheng, Youye; Sun, Xiang; Gao, Shunbao; Zhao, Zhidan; Zhang, Gangyang; Wu, Song; You, Zhiming; Li, Jiandong

2014-01-01

365

Geochemistry, geochronology, and Sr-Nd isotopes of the Late Neoproterozoic Wadi Kid volcano-sedimentary rocks, Southern Sinai, Egypt: Implications for tectonic setting and crustal evolution  

NASA Astrophysics Data System (ADS)

The Kid Group is one of the few exposures of Neoproterozoic metavolcano-sedimentary rocks in the basement of southern Sinai in the northernmost Arabian-Nubian Shield. It is divided into the mostly metamorphosed volcaniclastic Melhaq and siliciclastic Um Zariq formations in the north and the mostly volcanic Heib and Tarr formations in the south. The Heib, Tarr, and Melhaq formations reflect an intense episode of igneous activity and immature clastic deposition associated with core-complex formation during Ediacaran time, but Um Zariq metasediments are relicts of an older (Cryogenian) sedimentary sequence. The latter yielded detrital zircons with concordant ages as young as 647 ± 12 Ma, which may indicate that the protolith of Um Zariq schist was deposited after ~ 647 Ma but 19 concordant zircons gave a 206Pb/238U weighted mean age of 813 ± 6 Ma, which may represent the maximum depositional age of this unit. In contrast, a cluster of 11 concordant detrital zircons from the Melhaq Formation yield a weighted mean 206Pb/238U age of 615 ± 6 Ma. Zircons from Heib Formation rhyolite clast define a 206Pb/238U weighted mean age of 609 ± 5 Ma, which is taken to approximate the age of Heib and Tarr formation volcanism. Intrusive syenogranite sample from Wadi Kid yields a 206Pb/238U weighted mean age of 604 ± 5 Ma. These constraints indicate that shallow-dipping mylonites formed between 615 ± 6 Ma and 604 ± 5 Ma. Geochemical data for volcanic samples from the Melhaq and Heib formations and the granites show continuous major and trace element variations corresponding to those expected from fractional crystallization. The rocks are enriched in large ion lithophile and light rare earth elements, with negative Nb anomalies. These reflect magmas generated by melting of subduction-modified lithospheric mantle, an inference that is further supported by ?Nd(t) = + 2.1 to + 5.5. This mantle source obtained its trace element characteristics by interaction with fluids and melts from subducting oceanic crust during the Late Cryogenian time, prior to terminal collision between fragments of East and West Gondwana at ~ 630 Ma. Positive ?Nd(t) values and the absence of pre-Ediacaran zircons in all but Um Zariq metasediments indicate minor interaction with Cryogenian and older crust. A model of extensional collapse following continental collision, controlled mainly by lithospheric delamination and slab break-off is suggested for the origin of the post-collision volcanics and granites at Wadi Kid. No evidence of pre-Neoproterozoic sources was found. Kid Group Ediacaran volcanic rocks are compositionally and chronologically similar to the Dokhan Volcanics of NE Egypt, which may be stratigraphic equivalents.

Moghazi, Abdel-Kader M.; Ali, Kamal A.; Wilde, Simon A.; Zhou, Qin; Andersen, Tom; Andresen, Arild; Abu El-Enen, Mahrous M.; Stern, Robert J.

2012-12-01

366

Morphometric analysis of drainage network in the northern sector of the southern Italian foredeep: implications for fluvial denudation processes and Late Quaternary geomorphological evolution  

NASA Astrophysics Data System (ADS)

We present new data about the morphological and stratigraphic evolution and the rates of fluvial denudation of an area located in the northernmost sector of the foredeep of the southern Apennines. The study area is the medium- to low-relief sector located between the easternmost part of the Daunia Apennine and the Apulian foreland of the Gargano promontory. This area is characterized by several orders of terraced fluvial deposits disconformably overlying lower Pleistocene marine clay and organized in a staircase geometry, which recorded the emersion and the long-term incision history of this sector since mid-Pleistocene times. Geomorphological analyses have been carried out in order to retrace the landscape evolution of the area and its relationships with tectonic- and eustatic-induced variations of base-levels of erosion. Drainage network morphometry and the estimation of several topographic attributes have been added to the data collected through photo-aerial geomorphological interpretation and field survey. Drainage pattern, morphometric indexes and geological data seem to indicate that the thrust front is not active in the Late Quaternary. Paleotopographic reconstruction of ancient base-levels of erosion has permitted to calculated missing volumes. The estimation of eroded volumes in river valleys was performed through a GIS-aided calculation supported by a DEM with spatial resolution of 8 m, using the several orders of terraced deposits recognized in the area. The mapped remnants of relict geomorphological land surfaces have been interpolated by geospatial analysis and subtracted pixel by pixel to the present-day topography. Then, denudation rates were calculated on the basis of the relative age assigned to the deposits. Middle to upper Pleistocene denudation rates estimated by means of such an approach are about 0.1 mm/y, in good agreement with data coming from direct and indirect evaluation of transport sediment yield. The analysis of longitudinal river profiles using the stream power erosion model provided additional information on the incision rates of the studied area. The Late Quaternary uplift rate (0.15 mm/y), calculated on the basis of the elevation above sea level of the marine deposits outcropping in the easternmost sector of the study area, is quite similar to the erosion rates average value, so suggesting a steady-state fluvial incision.

Gioia, D.; Moretti, M.; Gallicchio, S.; Schiattarella, M.

2012-04-01

367

Implication of the southern Tethyan Himalaya (Sutlej section, India) for the extrusion of the Higher Himalaya and the geometry of the mid-crustal channel  

NASA Astrophysics Data System (ADS)

In the last three years, various combinations of channel flow and critical taper mechanisms have been suggested as plausible mechanism for the extrusion of the Higher Himalaya (HH, Beaumont and Jamieson 2010; Chambers et al., 2011; Larson et al., 2011; Corrie et al., 2012; Long et al. 2012; Mukherjee, in press). An alternate and rather less popular model of the HH has been southward droop of the northern boundary of the HH viz. the 'South Tibetan Detachment System-Upper (STDSU)' (Exner et al. 2006). Had the later been true, drag folds with southward vergence would be expected immediately north of the STDSU. In a SW to NE traverse from Morang up to Spillo along the Sutlej river valley (Himachal Pradesh, India), such folds do occur within the southern part of the Tethyan Himalaya. On close observation, the primary shear planes of top-to~S shear are overturned by folds with broad rounded hinges and with ~ NE dipping axial planes and limbs. The shear sense indicated by the sigmoid fabrics matches with the asymmetry of the folds. Northward from Spillo, large-scale folds (antiforms) with down-dip extensional shear in both limbs indicate 'irregular' doming of the Tethyan sediments. One of the best exposures of this shear sense that could be deciphered even from a distance is where the National Highway 22 running along the river valley joins the road to Nasang village. Below the Tethyan sediments, a mid-crustal sub-horizontal channel is widely accepted to allow the Higher Himalayan rock materials to flow from beneath south Tibet. Much north of Spillo, the Leo Pargil granite-gneiss dome has been suggested as an exposure of the channel materials. Thus, this work suggests (i) flap of the STDSU might have triggered the extrusion of the HH; and (ii) doming of a part of the Tethyan Himalaya could be due to the rise of low-density hot, partially molten rocks through the sub-horizontal channel. This would imply that the upper boundary of the sub-horizontal channel was flexible rather than rigid. Following Mancktelow (2008), the viscosity ratio between the mid-crustal material and that of the surrounding Tethyan sediments might be > 10-7.Taking the viscosity of the mid-crustal material as 1018-1019 Pa s, that for the Tethyan schists are loosely constrained as < 1025 to 1026 Pa s. This matches the viscosity values (between 500-700 0C: 1018-1019 Pa s) given for schists by Landholt-Bornstein (1982).

Mukherjee, Soumyajit

2013-04-01

368

Mineralogical and microfabric characteristics of magnetite in the Wuyang Precambrian BIFs, southern North China Craton: Implications for genesis and depositional processes of the associated BIFs  

NASA Astrophysics Data System (ADS)

Precambrian Banded Iron Formations (BIFs) are widely distributed in the North China Craton (NCC). Among them, the Wuyang BIFs located in the southern margin of NCC occur in the Late Archaean Tieshanmiao Formation and can be subdivided in two different sub-types: (i) quartz-magnetite BIFs (QMB), consisting of magnetite, fine-microcrystalline quartz and minor calcite and (ii) pyroxene-magnetite BIFs (PMB), composed of pyroxene, fine-microcrystalline quartz and subordinate feldspars. Both sub-types display apparent discrepancies in terms of petrography and mineral composition. As shown in Electron BackScattered Diffraction (EBSD) images and micrographs, magnetite grains from the QMB range in size from tens up to hundreds of ?m, whereas magnetite crystals from the PMB can be up to a few tens of ?m across. The X-ray diffraction (XRD) structural data indicate that magnetite from both BIF sub-types is equiaxed (cubic) and was generated by sedimentary metamorphic processes. The cell parameters of magnetite in the QMB are a = b = c = 8.396 Å and Z = 8, which deviate slightly from these of magnetite in the PMB: a = b = c = 8.394 Å and Z = 8. The analytical results of Raman spectroscopy analysis revealed micro-structural signatures of both magnetite (Raman shifts near 552 cm-1 and 673 cm-1) and hematite (Raman shifts near 227 cm-1, 295 cm-1 and 413 cm-1). In magnetite from both QMB and PMB, the crystallinity degree is similar for magnetite micro-structures but varies significantly for hematite micro-structures. Oxygen fugacity (fO2) conditions fluctuated during the recrystallization of magnetite in the QMB, whereas no evident variation of fO2 occurred during the formation of magnetite in the PMB. Analytical results of laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) show that the Si, Al and Mg abundances are higher in magnetite from the QMB, whereas the Ti and Mn contents are more elevated in magnetite from the PMB. Magnetite composition also denotes that both BIF sub-types are sedimentary-metamorphic origin, whereas the deposition of PMB was also affected by volcanic activities. Overall data indicate that the differences in the depositional environment of each BIF sub-type are due to the involvement of volcanic eruption processes in the genesis of the PMB. Thus, this paper indicated that the QMB was deposited by chemical deposition at the long-term interval of volcanic eruptions, and the PMB were the product of chemical deposition affected by the volcanic eruption.

Li, Hongzhong; Zhai, Mingguo; Zhang, Lianchang; Yang, Zhijun; Kapsiotis, Argyrios; Zhou, Yongzhang; He, Junguo; Wang, Changle; Liang, Jin

2014-11-01

369

Late Quaternary incision rates in the Vésubie catchment area (Southern French Alps) from in situ-produced 36Cl cosmogenic nuclide dating: Tectonic and climatic implications  

NASA Astrophysics Data System (ADS)

We have estimated recent river incision rates using the in situ-produced 36Cl cosmogenic nuclide concentrations. The target site consists of a ~25 m high vertical profile along a polished river cliff located in Jurassic limestones in the Vésubie catchment area, in the southern French Alps. The 36Cl exposure ages of the sampled river polished surface range from 3 to 14 ka, i.e., after the Last Glacial Maximum. Our data suggest as a first approximation a linear age/height relationship and lead to a mean incision rate of 2.2 mm a-1 over the last 14 ka. More precisely, incision rates are characterized by two peaks reaching ~2 and 4-5 mm a-1 at 4-5 ka and 11-12 ka, respectively, separated by a period experiencing a lower incision rate (~1 mm a-1). A chi-plot of the river longitudinal profile suggests that on the long term, the river is close to equilibrium conditions with a concavity index of 0.475. The evolution of the Vésubie River longitudinal profile over a time period of 2 Ma based on the stream power law of river incision was then modeled with varying erodibility coefficients and uplift rates ranging from 0.5 to 2 mm a-1. The best fitting models yield erodibility coefficient values ranging from 2.5 to 9.0 × 10-6 m-0.475 a-1 for the considered uplift rates. For long-term uplift rates lower than 2 mm a-1, an increase of the erodibility coefficient during the last 16 ka, with two peaks at 11-12 and 4-5 ka, is necessary to precisely match the observed incision rates and is interpreted as resulting from recent climatic changes. These variations do not strongly affect the general shape of the river profile and suggest that the measured short-term incision rate is dominated by a climatic signal, which does not preclude the possible role of tectonic uplift.

Saillard, Marianne; Petit, Carole; Rolland, Yann; Braucher, Régis; Bourlès, Didier L.; Zerathe, Swann; Revel, Marie; Jourdon, Anthony

2014-05-01

370

Vegetation and geomorphic significance of the riparian greenline in the Sprague River basin, southern Oregon: implications for biogeomorphic monitoring of riparian corridors in semi-arid mountain valleys  

NASA Astrophysics Data System (ADS)

Like many regions in the western U.S., valley-floor environments of the semi-arid Sprague River basin of southern Oregon are heavily irrigated and widely grazed by cattle. To better understand the impacts of grazing and other land uses on river quality, the Klamath Tribes have begun a long-term, basin-wide program aimed at: (1) establishing baseline geomorphic and vegetative conditions along the Sprague River and its tributaries, and (2) monitoring changes in these conditions over time. Because of its widespread use and ease of application, determining the composition of the lowest line of perennial vegetation above baseflow, or the “greenline,” has been included. The goal of this paper is to summarize results of 38 greenline surveys conducted at 19 sites in 2008-9 and to explore geomorphic hypotheses that may explain vegetation patterns evident in the surveys. Spikerush (Eleocharis ssp.) and reed-canary grass (Phalaris arudinacea) were the most commonly occurring vegetation in the greenline across all sites. Because these species are aggressive colonizers, they indicate high availability of fresh alluvium, which may be associated with sustained channel-bank disturbance. Sedges dominated some portions of the greenline at most of the sites, but occurred in less abundance. The late successional or early-to-late transitional state of these sedges, combined with their relatively low frequency, further supports the hypothesis that channel-bank systems remain chronically disturbed and dynamic. Grazing is common, but variable in intensity, at nearly all of the study sites, likely contributing to the persistence of channel-bank disturbance. Among meandering channels, the richness of dominant species (i.e., “community diversity”) was higher on the outer bends than on the inner bends of meanders at 10 of 12 sites. The variability of geomorphic surfaces (old floodplain, new floodplain, failed bank, accreted toe, etc.) incorporated in the greenline by the spatially discontinuous processes of channel-bank erosion and failure on the outer meander bends appears to increase the types of habitats surveyed and their combined biodiversity. In contrast, the spatial continuity of bar accretion on the inner meander bends appears to result in a more uniform geomorphic setting with fewer dominant species in the greenline. Despite widespread recognition that geomorphic processes influence riparian vegetation, factors such as the type and severity of bank erosion, the location of the survey with respect to meander geometry, and the type of geomorphic surface underlying greenline observations are not explicitly included in published guidance for biogeomorphic monitoring of the riparian greenline. Inclusion of such factors would improve communication, study design, and application of research by fluvial geomorphologists, riparian ecologists, and resource managers utilizing the greenline methodology.

Hughes, M. L.; Leeseberg, C.

2009-12-01

371

Ages and origins of rocks of the Killingworth dome, south-central Connecticut: Implications for the tectonic evolution of southern New England  

USGS Publications Warehouse

The Killingworth dome of south-central Connecticut occurs at the southern end of the Bronson Hill belt. It is composed of tonalitic and trondhjemitic orthogneisses (Killingworth complex) and bimodal metavolcanic rocks (Middletown complex) that display calc-alkaline affinities. Orthogneisses of the Killingworth complex (Boulder Lake gneiss, 456 ?? 6 Ma; Pond Meadow gneiss, ???460 Ma) were emplaced at about the same time as eruption and deposition of volcanic-sedimentary rocks of the Middletown complex (Middletown Formation, 449 ?? 4 Ma; Higganum gneiss, 459 ?? 4 Ma). Hidden Lake gneiss (339 ?? 3 Ma) occurs as a pluton in the core of the Killingworth dome, and, on the basis of geochemical and isotopic data, is included in the Killingworth complex. Pb and Nd isotopic data suggest that the Pond Meadow, Boulder Lake, and Hidden Lake gneisses (Killingworth complex) resulted from mixing of Neoproterozoic Gander terrane sources (high 207Pb/204Pb and intermediate ??Nd) and less radiogenic (low 207Pb/204Pb and low ??Nd) components, whereas Middletown Formation and Higganum gneiss (Middletown complex) were derived from mixtures of Gander basement and primitive (low 207Pb/204Pb and high ??Nd) sources. The less radiogenic component for the Killingworth complex is similar in isotopic composition to material from Laurentian (Grenville) crust. However, because published paleomagnetic and paleontologic data indicate that the Gander terrane is peri-Gondwanan in origin, the isotopic signature of Killingworth complex rocks probably was derived from Gander basement that contained detritus from non-Laurentian sources such as Amazonia, Baltica, or Oaxaquia. We suggest that the Killingworth complex formed above an east-dipping subduction zone on the west margin of the Gander terrane, whereas the Middletown complex formed to the east in a back-arc rift environment. Subsequent shortening, associated with the assembly of Pangea in the Carboniferous, resulted in Gander cover terranes over the Avalon terrane in the west; and in the Middletown complex over the Killingworth complex in the east. Despite similarities of emplacement age, structural setting, and geographic continuity of the Killingworth dome with Oliverian domes in central and northern New England, new and published isotopic data suggest that the Killingworth and Middletown complexes were derived from Gander crust, and are not part of the Bronson Hill arc that was derived from Laurentian crust. The trace of the Ordovician Iapetan suture (the Red Indian line) between rocks of Laurentian and Ganderian origin probably extends from Southwestern New Hampshire west of the Pelham dome of northcentral Massachusetts and is coverd by Mesozoic rocks of the Hartford basin.

Aleinikoff, J.N.; Wintsch, R.P.; Tollo, R.P.; Unruh, D.M.; Fanning, C.M.; Schmitz, M.D.

2007-01-01

372

Total and incremental left-lateral displacement across the East Gobi Fault Zone, southern Mongolia: Implications for timing and modes of polyphase intracontinental deformation  

NASA Astrophysics Data System (ADS)

The East Gobi Fault Zone (EGFZ) is a dominant structural feature in southeastern Mongolia. The EGFZ's protracted history includes at least five distinct deformation events occurring over the last 250 million years. Two of these phases are marked by left-lateral motion, but the total and incremental displacement history is poorly known. A better understanding of the displacement history across the EGFZ is required to place its Mesozoic and Cenozoic evolution within the larger context of central Asian tectonics, including evaluating the EGFZ's possible role as an intracontinental extrusion feature. This study presents analysis of sedimentary and igneous rocks as proposed offset markers on either side of the EGFZ. New geochronologic data, integrated with existing structural and stratigraphic data, are used to characterize and quantify two periods of left-lateral displacement along the EGFZ. The slip history of the EGFZ includes a total of ?250-300 km of left-lateral displacement. Approximately 150-200 km of slip occurred along a major shear zone during the Late Triassic (?225-210 Ma), based on restoration of Carboniferous intrusive suites and Permian remnant ocean basin deposits. During this first period of left-lateral displacement, the EGFZ acted as a continental extrusion feature responding to oblique collision between the South and North China Blocks and northern Mongolia and Siberia, an event analogous to the later India-Asia collision during the Cenozoic. A second period of ?90-100 km of left-lateral slip occurred in the Late Oligocene, based on offset of Lower Cretaceous strata and cross-cutting relationships. This brittle deformation phase was contemporaneous with dynamic boundary conditions along the Pacific margin, and the Indo-Asia collision. Cenozoic movement along the EGFZ may have coincided kinematically with the Altyn Tagh Fault in China via dispersed fault zones in the Alxa region. Major displacement along the EGFZ likely ceased in the early Miocene, coincident with changing relative plate motions at the Pacific margin. Magnitudes of Cenozoic offset across the EGFZ are significantly smaller than estimated for the Altyn Tagh Fault, which likely reflects distributed deformation in heterogeneous crust of the southern Central Asian Orogenic Belt.

Heumann, Matthew J.; Johnson, Cari L.; Webb, Laura E.; Taylor, Joshua P.; Jalbaa, Undarya; Minjin, Chuluun

2014-04-01

373

Antibody seroprevalences against Peste des Petits Ruminants (PPR) virus in sheep and goats in Sudan.  

PubMed

Counter immnuo-electrophoresis (CIEP) and Competitive ELISA (C-ELISA) tests were employed for seroprevalence of Peste des Petits Ruminants (PPR) infection in Sudan. The result of both tests showed high prevalence of PPRV antibodies in sheep and goats sera collected from six different regions of Sudan. Of the 519 serum samples examined for the presence of PPRV antibodies 307(59.15%) were positive by CIEP while 263(50.67%) were positive by C-ELISA. CIEP technique was shown to be more sensitive than C-ELISA technique for detection of PPRV antibodies (Kappa statistics 0.259). C-ELISA allowed rapid, simple, specific, sensitive and differential sero-diagnosis of PPRV and RPV in sheep, goats and cattle. CIEP is, unlike competitive ELISA, is group-specific test and can not differentiate between PPR and RP infections. Despite its low specificity CIEP can be a useful indicative screening test for PPRV antibodies in flocks that neither been vaccinated nor otherwise exposed to PPR or RP virus. Results obtained suggest that CIEP, like the HI test, could be a useful screening test where it is not possible to use C-ELISA. PMID:19798772

Osman, Nussieba A; Ali, A S; A/Rahman, Mahasin E; Fadol, M A

2009-10-01

374

A serological survey of akabane virus infection in cattle in Sudan.  

PubMed

A cross-sectional survey was carried out in ten states in Sudan to determine seroprevalence and to assess risk factors associated with Akabane virus (AKAV) infection in dairy herds. Serum samples were collected from a total of 361 dairy cattle and tested for antibodies against AKAV using ELISA. The prevalence rates of AKAV antibodies in cattle varied between 69.6% in Khartoum state and 3.3% in Sennar State with an overall prevalence rate of 29.4%. The prevalence rates of AKAV antibodies were significantly associated with breed being high in crossbred (39.9%; P < 0.001); female sex (33%; P < 0.001), and animals in the age group of 2-3 years old (45.3%; P < 0.001). Akabane virus antibodies prevalence was also highly associated with locality (P < 0.001); season being high in winter season (58.1%; P < 0.001); and animals raised under intensive management system (37%; P < 0.001). Among 68 cases suffering from reproductive (abortion and infertility) problems the prevalence rate of AKAV antibodies in animals with infertility problem (76.2%; P < 0.03) was significantly higher than in animals with abortion (48.9%). The study revealed that AKAV infection is highly prevalent in dairy cattle in Sudan and this calls for control strategy to be implemented. PMID:24977042

Elhassan, Amira M; Mansour, Mohammed E A; Shamon, Awadia A A; El Hussein, A M

2014-01-01

375

Controlling medicine prices in Sudan: the challenge of the recently established medicines regulatory authority.  

PubMed

This study evaluated the capacity of the medicine pricing mechanism of the National Medicines and Poisons Board (NMPB), the medicine regulatory agency of Sudan, in controlling prices of imported medicines. The study was conducted between July and September 2008 and data on the 50 most sold medicines in 2007 were obtained from the records of the regulatory authority and pharmacies in Khartoum; 135 products were included. The cost and freight (C&F) prices of 23% of the selected medicines approved by NMPB were over 10 times the International Reference Price; 71% of these items were generics. The wholesale price of only 40% of the studied medicines was less than that approved by NMPB, while the retail price of 47% of medicines was less than that approved by the authority. The retail price of 11 of 12 originator medicines was equal to or more than their prices published in the British National Formulary. The price of the medicines distributed by Central Medical Supplies was about 2-fold their C&F price. The current pricing system is of limited benefit in controlling medicine prices in Sudan. PMID:23057369

Ali, G K M; Yahia, Y

2012-08-01

376

Prevalence of Protozoa Species in Drinking and Environmental Water Sources in Sudan  

PubMed Central

Protozoa are eukaryotic cells distributed worldwide in nature and are receiving increasing attention as reservoirs and potential vectors for the transmission of pathogenic bacteria. In the environment, on the other hand, many genera of the protozoa are human and animal pathogens. Only limited information is available on these organisms in developing countries and so far no information on their presence is available from Sudan. It is necessary to establish a molecular identification of species of the protozoa from drinking and environmental water. 600 water samples were collected from five states (Gadarif, Khartoum, Kordofan, Juba, and Wad Madani) in Sudan and analysed by polymerase chain reaction (PCR) and sequencing. 57 out of 600 water samples were PCR positive for protozoa. 38 out of the 57 positive samples were identified by sequencing to contain 66 protozoa species including 19 (28.8%) amoebae, 17 (25.7%) Apicomplexa, 25 (37.9%) ciliates, and 5 (7.6%) flagellates. This study utilized molecular methods identified species belonging to all phyla of protozoa and presented a fast and accurate molecular detection and identification of pathogenic as well as free-living protozoa in water uncovering hazards facing public health. PMID:25789313

Shanan, Salah; Abd, Hadi; Bayoumi, Magdi; Saeed, Amir; Sandström, Gunnar

2015-01-01

377

The seroprevalence of parvovirus B19 infection in pregnant women in Sudan.  

PubMed

Parvovirus B19 (B19V) infection during pregnancy may have serious consequences like fetal anaemia, hydrops fetalis, and fetal loss. Since epidemiological data on B19V infection are generally lacking in Sudan, the current study aimed to determine the seroprevalence of B19V in Sudanese pregnant women. Five hundred women, attending antenatal clinics in Khartoum state between November 2008 and March 2009, were enrolled and screened for B19V IgG and IgM antibodies by enzyme immunoassays. The study revealed a B19V IgG seroprevalence of 61·4%, with one subject positive for IgM. B19V DNA was not detected by PCR in any of the tested individuals. B19V IgG seroprevalence was significantly correlated with multigravidity (P = 0·046). Our data showed that B19V infection is prevalent in Sudan and we recommend further studies in Sudanese women, particularly in those with complications and adverse outcomes of pregnancy. PMID:24650427

Adam, O; Makkawi, T; Reber, U; Kirberg, H; Eis-Hübinger, A M

2015-01-01

378

Mesozoic palynology and continental sediments in NE Africa (Egypt and Sudan) - a review  

NASA Astrophysics Data System (ADS)

In Egypt and Sudan most palynogical data are derived from predominantly clastic sequences in research wells for oil, water and other sedimentary deposits. The partly coal-bearing Middle Jurassic is characterized by dominance of pteridophytes while increasing percentages of gymnosperms may be noted in the Late Jurassic. The Jurassic-Cretaceous boundary is difficult to define, but Ischyosporites-Cicatricosisporites assemblages have been interpreted as Late Jurassic and overlying assemblages with Impardecispora, Geicheniidites, Classopollis etc. as Neocomian. The appearance of rare early angiosperms and their subsequent rise is documented e.g. in the Six Hills (Barremian) and in the shallow marine Abu Ballas Formation (Aptian). More advanced angiosperm types (tricolpates, tricolporates, triporates) occur in the post-Aptian. Elater-bearing spores ( Elaterosporites) associated with Afropollis form a distinctive element of the Albian (to Early Cenomanian) palynofloras known from Northern Egypt and recently discovered in Northern Sudan. In the Coniacian-Santonian, the spinose tetrads of Droseridites senonicus and large tricolpate pollen of the Foveotricolpites giganteus group become the most characteristic members of the terrestrial palynofloras. Distinctly marine palynomorphs reach the middle latitudes of Egypt for the first time with the Campanian-Maastrichtian transgression. Reduced salinity in the Phosphate Formation is reflected by peridinoid (e.g. Andalusiella, Senegalinium) communities interfingering with pollen and spores dominated associations. More open marine conditions in the overlying Dakhla Shale are documented by the rise of cosmopolitan gonyaulacoids such as Spiniferites, Glaphyrocysta and Florentinia.

Schrank, E.

379

Serological survey of canine leptospirosis in three countries of tropical Africa: Sudan, Gabon and Ivory Coast.  

PubMed

A cross-sectional survey was conducted to estimate the presence of leptospiral antibodies among 475 dogs from three countries of tropical Africa: Sudan (n=62), Gabon (n=255) and Ivory Coast (n=158). Sixteen reference strains belonging to seven serogroups were used as antigen in the microscopic agglutination test. Overall, considering titres ?1:40, 453 samples were positive towards one or several serovars of pathogenic leptospires. Focusing on high titres, i.e. ?1:320, the seroprevalence was 40.8%. In Gabon, the seroprevalence was higher in rural areas than in an urban environment (p<0.001). In Ivory Coast, the seroprevalence for serogroups Icterohaemorrhagiae and Canicola was not statistically different according to the vaccinal status. Predominant serogroups varied according to the countries but Grippotyphosa and Sejroë were the most common, while Icterohaemorragiae and Canicola were dominant in Sudan. In these three countries, dogs are heavily exposed to pathogenic Leptospira and humans living in the same environment are also at risk of infection. PMID:25467033

Roqueplo, Cédric; Marié, Jean-Lou; André-Fontaine, Geneviève; Kodjo, Angeli; Davoust, Bernard

2015-02-01

380

Photocatalytic degradation of Azure and Sudan dyes using nano TiO2.  

PubMed

The present study investigates the dependence of photocatalytic rate on molecular structure of the substrate that is degraded. The photocatalytic degradation of Azure (A and B) and Sudan (III and IV) dyes, having similar structure, but different functional groups, were investigated with two catalysts. The photocatalytic activity of solution combustion synthesized TiO(2) (CS TiO(2)) was compared with that of Degussa P-25 for degrading these dyes. The effect of solvents and mixed-solvent system on photodegradation of Sudan III was investigated. The photodegradation rate was found to be higher in solvents with higher polarity. The effect of pH and the presence of metal ions in the form of chloride and nitrate salt, on degradation rate of Azure A was also investigated. The metal ions significantly reduced the photocatalysis rates. A detailed Langmuir-Hinshelwood kinetic model has been developed to explain the effect of metal ions on degradation rate of the substrate. This model elucidates the contribution of holes and electrons towards degradation of the dye. PMID:17540499

Aarthi, T; Narahari, Prashanthi; Madras, Giridhar

2007-11-19