Basin characterization and determination of hydraulic connectivity of mega basins using integrated methods: (The case of Baro-Akobo and mega watershed beyond)

NASA Astrophysics Data System (ADS)

Alemayehu, Taye; Kebede, Tesfaye; Liu, Lanbo

2018-01-01

Despite being the longest river and the fourth in drainage area, Nile River has the lowest discharge per unit areas among the top ten rivers of the world. Understanding the hydrologic significance of the regional litho-stratigraphy and structures help to better understand the hydrodynamics. This work is aimed at characterizing the Baro-Akobo-Sobbat sub-basin of Nile and determine trans-basin flows. Integrated method is used to characterize the basin and determine the Baro-Akobo-Sobbat sub-basin's relationship with African Mesozoic Rifts. Oil and water well drilling logs; aeromagnetic, gravity and vertical electrical sounding data; and various study reports are used to establish regional lithostratigraphic correlations and determine trans-regional hydrogeological connectivity. A total of 633 samples collected from wells, springs, rivers, lakes, swamps and rain water are analysed for their chemical, stable isotopes, tritium and radon properties. The Baro-Akobo river basin is commonly presumed to have good groundwater potential, particularly in its lowland plain. However, it has poor exploitable groundwater potential and recharge rate due to the extensive clay cover, limited retention capacity and the loss of the bulk of the groundwaters through regional geological structures to the deep seated continental sediments; presumably reaching the hydraulically connected African Mesozoic Rifts; mainly Melut and Muglad. The deep underground northward flows, along Nile River is, presumably, retarded by Central African Shear Zone in the Sudan.

Holocene Flexural Deformation over the Nile Delta: Evidence from Radar Interferometry

NASA Astrophysics Data System (ADS)

Gebremichael, E.; Sultan, M.; Becker, R.

2017-12-01

Isostatic adjustment and subsequent subsidence and uplift due to sediment and water loading and unloading mechanisms is one of the major factors that produce regional deformational patterns across river deltas. Using 84 Envisat ASAR scenes that were acquired (2004 - 2010) along three tracks and applying Persistent scatterer (PS) radar interferometric techniques, we documented flexural deformational patterns over the entire Nile Delta (length: 186 km; width: 240 km) of Egypt. The passive continental margin of Africa subsided from Jurassic time onwards due to isostatic loading creating an accommodation space and consequently, the deposition of relatively younger sediments on the oceanic crust. In river deltas, the flexural isostasy model dictates that a subsidence in the oceanic crust side should be balanced by a bulge (uplift) in the flanking regions. Using radar interferometry, we were able to identify the flexural deformation pattern and map its spatial extent over the northern and central Nile Delta region. Findings include: (1) the northern Nile Delta region (block) is separated from the southern delta region by an east-west trending, extensively faulted, hinge line that signifies the boundary between two deformational patterns (subsidence and uplift). It separates the highly subsiding (up to 9.8 mm/yr) northern delta block (up to 85 km long) from the nearly stable (0.4 mm/yr; averaged) southern delta block (up to 91 km long). The hinge line marks the end of the passive continental margin of Africa and the beginning of the oceanic crust of the Mediterranean. (2) We mapped the extent of a 20-40 km wide flexural uplift zone to the south of the hinge line. Within the flexural uplift zone (2.5 mm/yr; averaged), there is a gradual increase in uplift rate reaching peak value (up to 7 mm/yr) near the midpoint of the zone. (3) The uplift rate gradually decreases south of the flexure boundary reaching 0.3 mm/yr at the southern periphery of the delta. (4) The flexural deformation pattern is interrupted (replaced by subsidence) in some areas due to local deformation caused by high groundwater extraction rates in western (6 mm/yr) and gas extraction in north central delta (9 mm/yr).

Marine Collagen Peptides from the Skin of Nile Tilapia (Oreochromis niloticus): Characterization and Wound Healing Evaluation

PubMed Central

Hu, Zhang; Yang, Ping; Zhou, Chunxia; Li, Sidong; Hong, Pengzhi

2017-01-01

Burns can cause tremendous economic problems associated with irreparable harm to patients and their families. To characterize marine collagen peptides (MCPs) from the skin of Nile tilapia (Oreochromis niloticus), molecular weight distribution and amino acid composition of MCPs were determined, and Fourier transform infrared spectroscopy (FTIR) was used to analyze the chemical structure. Meanwhile, to evaluate the wound healing activity, in vitro and in vivo experiments were carried out. The results showed that MCPs prepared from the skin of Nile tilapia by composite enzymatic hydrolysis were composed of polypeptides with different molecular weights and the contents of polypeptides with molecular weights of less than 5 kDa accounted for 99.14%. From the amino acid composition, the majority of residues, accounting for over 58% of the total residues in MCPs, were hydrophilic. FTIR indicated that the main molecular conformations inside MCPs were random coil. In vitro scratch assay showed that there were significant effects on the scratch closure by the treatment of MCPs with the concentration of 50.0 μg/mL. In the experiments of deep partial-thickness scald wound in rabbits, MCPs could enhance the process of wound healing. Therefore, MCPs from the skin of Nile tilapia (O. niloticus) have promising applications in wound care. PMID:28358307

Marine Collagen Peptides from the Skin of Nile Tilapia (Oreochromis niloticus): Characterization and Wound Healing Evaluation.

PubMed

Hu, Zhang; Yang, Ping; Zhou, Chunxia; Li, Sidong; Hong, Pengzhi

2017-03-30

Burns can cause tremendous economic problems associated with irreparable harm to patients and their families. To characterize marine collagen peptides (MCPs) from the skin of Nile tilapia ( Oreochromis niloticus ), molecular weight distribution and amino acid composition of MCPs were determined, and Fourier transform infrared spectroscopy (FTIR) was used to analyze the chemical structure. Meanwhile, to evaluate the wound healing activity, in vitro and in vivo experiments were carried out. The results showed that MCPs prepared from the skin of Nile tilapia by composite enzymatic hydrolysis were composed of polypeptides with different molecular weights and the contents of polypeptides with molecular weights of less than 5 kDa accounted for 99.14%. From the amino acid composition, the majority of residues, accounting for over 58% of the total residues in MCPs, were hydrophilic. FTIR indicated that the main molecular conformations inside MCPs were random coil. In vitro scratch assay showed that there were significant effects on the scratch closure by the treatment of MCPs with the concentration of 50.0 μg/mL. In the experiments of deep partial-thickness scald wound in rabbits, MCPs could enhance the process of wound healing. Therefore, MCPs from the skin of Nile tilapia ( O. niloticus ) have promising applications in wound care.

Synoptic conditions of fine-particle transport to the last interglacial Red Sea -Dead Sea from Nd-Sr compositions of sediment cores

NASA Astrophysics Data System (ADS)

Stein, M.; Palchan, D.; Goldstein, S. L.; Almogi-Labin, A.; Tirosh, O.; Erel, Y.

2017-12-01

The last interglacial peak, Marine Isotope Stage 5e (MIS 5e), was associated with stronger northern hemisphere insolation, higher global sea levels and higher average global temperatures compared to the Holocene, and is considered as an analogue for a future warming world. In this perspective the present-day areas of the Sahara - Arabia deserts (the "desert belt") are of special interest since their margins are densely inhabited and global climate models predict enhanced aridity in these regions due to future warming. The Red Sea situated at the midst of the desert belt and the Dead Sea at the northern fringe of the desert belt comprise sensitive monitors for past hydroclimate changes in the Red Sea-Levant regions as global climate shifted from glacial to interglacial conditions. Here, we reconstruct the synoptic conditions that controlled desert dust transport to the Red Sea and the Dead Sea during MIS5e. The reconstruction is based on Nd-Sr isotopes and chemical composition of carbonate-free detritus recovered from sediment cores drilled at the deep floors of these water-bodies combined with data of contemporaneous dust storms transporting dust to the lake and sea floors. During Termination 2 ( 134-130 ka) the Sahara, Nile River desiccated and the Dead Sea watershed were under extreme dry conditions manifested by lake level drop, deposition of salt and enhanced transport of Sahara dusts to the entire studied transect. At the peak of the interglacial MIS 5e ( 130-120 ka), enhanced flooding activity mobilized local fine detritus from the surroundings of the Red Sea and the Dead Sea watershed into the water-bodies. This interval coincided with the Sapropel event S5 in the Mediterranean that responded to enhanced monsoon rains at the heads of the Blue Nile River. At the end of MIS 5e ( 120-116 ka) the effect of the regional floods faded and the Dead Sea and Red Sea areas re-entered sever arid conditions with salt deposition at the Dead Sea. Overall, the desert margins were under turbulent climate regime during the last interglacial period, fluctuating between contraction and expansions manifested with extreme enhanced flooding and extreme arid spells.

Multiproxy Late Quaternary stratigraphy of the Nile deep-sea turbidite system — Towards a chronology of deep-sea terrigeneous systems

NASA Astrophysics Data System (ADS)

Ducassou, E.; Capotondi, L.; Murat, A.; Bernasconi, S. M.; Mulder, T.; Gonthier, E.; Migeon, S.; Duprat, J.; Giraudeau, J.; Mascle, J.

2007-08-01

Understanding the recent formation of a sedimentary system such as a deep-sea turbidite system (DSTS) requires an accurate stratigraphic control on deposits. Due to the important terrigeneous input which disrupts the sedimentary record, DSTS is an environment where stratigraphic control is difficult to assess. Most of the time, traditional stratigraphic tools are not accurate enough. This has led to a rather limited number of studies concerning stratigraphy in DSTS. In this study, we examine several hemipelagic long piston cores collected from the Nile DSTS (eastern Mediterranean), in order to understand the recent evolution of the complex sedimentary system in this area. The first aim of this study is to show how to obtain a reliable timeframe in DSTS. Indeed, we provided a detailed ecostratigraphical scheme based on planktonic foraminiferal distribution, oxygen isotope records and lithostratigraphy (sapropels and tephra) of three cores where the sedimentation is least disturbed. We have identified 29 foraminiferal ecozones during the last 250,000 years BP, with an approximately 2000-year time resolution. The time span of each ecozone was constrained by the oxygen isotope record, 14C AMS radiometric data, tephrochronology and the sapropel chronology. These high-resolution ecostratigraphical time subdivisions have been applied in discontinuous mixed hemipelagic/turbiditic sequences of a levee record. This example shows how to date gravity events, formation and time periods of sedimentary accumulations.

Mesozoic evolution of northeast African shelf margin, Libya and Egypt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aadland, R.K.; Schamel, S.

1989-03-01

The present tectonic features of the northeast African shelf margin between the Nile delta and the Gulf of Sirte are products of (1) precursory late Paleozoic basement arches, (2) early Mesozoic rifting and plate separation, and (3) Late Cretaceous structural inversion. The 250 km-wide and highly differentiated Mesozoic passive margin in the Western Desert region of Egypt is developed above a broad northwest-trending Late Carboniferous basement arch. In northeastern Libya, in contrast, the passive margin is restricted to just the northernmost Cyrenaica platform, where subsidence was extremely rapid in the Jurassic and Early Cretaceous. The boundary between the Western Desertmore » basin and the Cyrenaica platform is controlled by the western flank of the basement arch. In the middle Cretaceous (100-90 Ma), subsidence accelerated over large areas of the Western desert, further enhancing a pattern of east-west-trending subbasins. This phase of rapid subsidence was abruptly ended about 80 Ma by the onset of structural inversion that uplifted the northern Cyrenaica shelf margin and further differentiated the Western Desert subbasin along a northeasterly trend.« less

Deep-sea environment and biodiversity of the West African Equatorial margin

NASA Astrophysics Data System (ADS)

Sibuet, Myriam; Vangriesheim, Annick

2009-12-01

The long-term BIOZAIRE multidisciplinary deep-sea environmental program on the West Equatorial African margin organized in partnership between Ifremer and TOTAL aimed at characterizing the benthic community structure in relation with physical and chemical processes in a region of oil and gas interest. The morphology of the deep Congo submarine channel and the sedimentological structures of the deep-sea fan were established during the geological ZAIANGO project and helped to select study sites ranging from 350 to 4800 m water depth inside or near the channel and away from its influence. Ifremer conducted eight deep-sea cruises on board research vessels between 2000 and 2005. Standardized methods of sampling together with new technologies such as the ROV Victor 6000 and its associated instrumentation were used to investigate this poorly known continental margin. In addition to the study of sedimentary environments more or less influenced by turbidity events, the discovery of one of the largest cold seeps near the Congo channel and deep coral reefs extends our knowledge of the different habitats of this margin. This paper presents the background, objectives and major results of the BIOZAIRE Program. It highlights the work achieved in the 16 papers in this special issue. This synthesis paper describes the knowledge acquired at a regional and local scale of the Equatorial East Atlantic margin, and tackles new interdisciplinary questions to be answered in the various domains of physics, chemistry, taxonomy and ecology to better understand the deep-sea environment in the Gulf of Guinea.

The Joint Operating Environment (JOE): Challenges and Implications for the Future Joint Force

DTIC Science & Technology

2008-11-25

the Nile and the Mesopotamian valleys were emerging. But those continuities and the cultural power of China’s civilization have...share a similar historical and cultural background, the mere fact of belligerence guarantees profound differences in attitudes, expectations...deep understanding of the enemy – his culture , history, geography, religious and ideological motivations, and particularly the huge differences

Deep Marginalized Sparse Denoising Auto-Encoder for Image Denoising

NASA Astrophysics Data System (ADS)

Ma, Hongqiang; Ma, Shiping; Xu, Yuelei; Zhu, Mingming

2018-01-01

Stacked Sparse Denoising Auto-Encoder (SSDA) has been successfully applied to image denoising. As a deep network, the SSDA network with powerful data feature learning ability is superior to the traditional image denoising algorithms. However, the algorithm has high computational complexity and slow convergence rate in the training. To address this limitation, we present a method of image denoising based on Deep Marginalized Sparse Denoising Auto-Encoder (DMSDA). The loss function of Sparse Denoising Auto-Encoder is marginalized so that it satisfies both sparseness and marginality. The experimental results show that the proposed algorithm can not only outperform SSDA in the convergence speed and training time, but also has better denoising performance than the current excellent denoising algorithms, including both the subjective and objective evaluation of image denoising.

Identification and Characterization of MicroRNAs in Ovary and Testis of Nile Tilapia (Oreochromis niloticus) by Using Solexa Sequencing Technology

PubMed Central

Zhou, Yi; Yu, Fan; Gao, Yun; Luo, Yongju; Tang, Zhanyang; Guo, Zhongbao; Guo, Enyan; Gan, Xi; Zhang, Ming; Zhang, Yaping

2014-01-01

MicroRNAs (miRNAs) are endogenous non-coding small RNAs which play important roles in the regulation of gene expression by cleaving or inhibiting the translation of target gene transcripts. Thereinto, some specific miRNAs show regulatory activities in gonad development via translational control. In order to further understand the role of miRNA-mediated posttranscriptional regulation in Nile tilapia (Oreochromis niloticus) ovary and testis, two small RNA libraries of Nile tilapia were sequenced by Solexa small RNA deep sequencing methods. A total of 9,731,431 and 8,880,497 raw reads, representing 5,407,800 and 4,396,281 unique sequences were obtained from the sexually mature ovaries and testes, respectively. After comparing the small RNA sequences with the Rfam database, 1,432,210 reads in ovaries and 984,146 reads in testes were matched to the genome sequence of Nile tilapia. Bioinformatic analysis identified 764 mature miRNA, 209 miRNA-5p and 202 miRNA-3p were found in the two libraries, of which 525 known miRNAs are both expressed in the ovary and testis of Nile tilapia. Comparison of expression profiles of the testis, miR-727, miR-129 and miR-29 families were highly expressed in tilapia ovary. Additionally, miR-132, miR-212, miR-33a and miR-135b families, showed significant higher expression in testis compared with that in ovary. Furthermore, the expression patterns of the miRNAs were analyzed in different developmental stages of gonad. The result showed different expression patterns were observed during development of testis and ovary. In addition, the identification and characterization of differentially expressed miRNAs in the ovaries and testis of Nile tilapia provides important information on the role of miRNA in the regulation of the ovarian and testicular development and function. This data will be helpful to facilitate studies on the regulation of miRNAs during teleosts reproduction. PMID:24466258

Immunogenicity of West Nile virus infectious DNA and its noninfectious derivatives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seregin, Alexey; Nistler, Ryan; Borisevich, Victoria

2006-12-20

The exceptionally high virulence of the West Nile NY99 strain makes its suitability in the development of a live WN vaccine uncertain. The aim of this study is to investigate the immunogenicity of noninfectious virus derivatives carrying pseudolethal mutations, which preclude virion formation without affecting preceding steps of the viral infectious cycle. When administered using DNA immunization, such constructs initiate an infectious cycle but cannot lead to a viremia. While the magnitude of the immune response to a noninfectious replication-competent construct was lower than that of virus or infectious DNA, its overall quality and the protective effect were similar. Inmore » contrast, a nonreplicating construct of similar length induced only a marginally detectable immune response in the dose range used. Thus, replication-competent noninfectious constructs derived from infectious DNA may offer an advantageous combination of the safety of noninfectious formulations with the quality of the immune response characteristic of infectious vaccines.« less

Reliability of skin biopsies in determining accurate tumor margins: a retrospective study after Mohs micrographic surgery.

PubMed

Koslosky, Cynthia Lynn; El Tal, Abdel Kader; Workman, Benjamin; Tamim, Hani; Durance, Michelle Christine; Mehregan, David Ali

2014-09-01

Skin biopsy reports of basal cell carcinoma and squamous cell carcinoma are often accompanied by comments on the margins. A physician's management can be influenced by such reports, particularly when the margins are reported as clear and no further interventions are pursued. To retrospectively review pathology margins on Mohs micrographic surgery (MMS) cases performed at a University Center and to compare biopsy margins with the Mohs margins found on the first stage. Data collection of 1,000 cases of Mohs surgery was obtained regarding margins on skin biopsy and compared with margins on the first stage of MMS. Overall, of the biopsies that showed only deep margin involvement, a lateral margin was seen on 32% of the first stages of MMS. Conversely, of the biopsies that showed only lateral margin involvement, a deep margin was seen on 14% of the first stages of MMS. Of the biopsies that showed clear margins, a margin was seen in 30% of the cases on the first stage of MMS. Skin biopsies processed through the "bread-loafing" technique are not reliable in detecting accurate margins, and therefore, a biopsy report should not include margin involvement within it.

New Insights into Passive Margin Development from a Global Deep Seismic Reflection Dataset

NASA Astrophysics Data System (ADS)

Bellingham, Paul; Pindell, James; Graham, Rod; Horn, Brian

2014-05-01

The kinematic and dynamic evolution of the world's passive margins is still poorly understood. Yet the need to replace reserves, a high oil price and advances in drilling technology have pushed the international oil and gas industry to explore in the deep and ultra-deep waters of the continental margins. To support this exploration and help understand these margins, ION-GXT has acquired, processed and interpreted BasinSPAN surveys across many of the world's passive margins. Observations from these data lead us to consider the modes of subsidence and uplift at both volcanic and non-volcanic margins. At non-volcanic margins, it appears that frequently much of the subsidence post-dates major rifting and is not thermal in origin. Rather the subsidence is associated with extensional displacement on a major fault or shear zone running at least as deep as the continental Moho. We believe that the subsidence is structural and is probably associated with the pinching out (boudinage) of the Lower Crust so that the Upper crust effectively collapses onto the mantle. Eventually this will lead to the exhumation of the sub-continental mantle at the sea bed. Volcanic margins present more complex challenges both in terms of imaging and interpretation. The addition of volcanic and plutonic material into the system and dynamic effects all impact subsidence and uplift. However, we will show some fundamental observations regarding the kinematic development of volcanic margins and especially SDRs which demonstate that the process of collapse and the development of shear zones within and below the crust are also in existence at this type of margin. A model is presented of 'magma welds' whereby packages of SDRs collapse onto an emerging sub-crustal shear zone and it is this collapse which creates the commonly observed SDR geometry. Examples will be shown from East India, Newfoundland, Brazil, Argentina and the Gulf of Mexico.

Post-fire ecohydrological conditions at peatland margins in different hydrogeological settings of the Boreal Plain

NASA Astrophysics Data System (ADS)

Lukenbach, M. C.; Hokanson, K. J.; Devito, K. J.; Kettridge, N.; Petrone, R. M.; Mendoza, C. A.; Granath, G.; Waddington, J. M.

2017-05-01

In the Boreal Plain of Canada, the margins of peatland ecosystems that regulate solute and nutrient fluxes between peatlands and adjacent mineral uplands are prone to deep peat burning. Whether post-fire carbon accumulation is able to offset large carbon losses associated with the deep burning at peatland margins is unknown. For this reason, we examined how post-fire hydrological conditions (i.e. water table depth and periodicity, soil tension, and surface moisture content) and depth of burn were associated with moss recolonization at the peatland margins of three sites. We then interpreted these findings using a hydrogeological systems approach, given the importance of groundwater in determining conditions in the soil-plant-atmosphere continuum in peatlands. Peatland margins dominated by local groundwater flow from adjacent peatland middles were characterized by dynamic hydrological conditions that, when coupled with lowered peatland margin surface elevations due to deep burning, produced two common hydrological states: 1) flooding during wet periods and 2) rapid water table declines during dry periods. These dynamic hydrological states were unfavorable to peatland moss recolonization and bryophytes typical of post-fire recovery in mineral uplands became established. In contrast, at a peatland margin where post-fire hydrological conditions were moderated by larger-scale groundwater flow, flooding and rapid water table declines were infrequent and, subsequently, greater peatland-dwelling moss recolonization was observed. We argue that peatland margins poorly connected to larger-scale groundwater flow are not only prone to deep burning but also lags in post-fire moss recovery. Consequently, an associated reduction in post-fire peat accumulation may occur and negatively affect the net carbon sink status and ecohydrological and biogeochemical function of these peatlands.

Eolian and riverine contributions to central-Mediterranean sediments: a high-resolution Holocene record

NASA Astrophysics Data System (ADS)

Wu, Jiawang; Böning, Philipp; Pahnke, Katharina; Tachikawa, Kazuyo; De Lange, Gert

2017-04-01

Circum-Mediterranean climate variability is reflected in sediments deposited and preserved at the Mediterranean seafloor. Alternating depositions of organic-lean marls and organic-rich sapropel sediments in the eastern Mediterranean Sea (EMS) are clearly related to precessional hydroclimate variability. The exact origin for freshwater sources and related changes therein during sapropel formation are still debated. Here, Sr and Nd isotopes and high-resolution elemental ratios from core CP10BC are used to unravel and constrain different eolian and riverine supplies from North Africa and from northern borderlands to the central Mediterranean over the past 9.8 ka. Based on Sr and Nd isotopic and elemental compositions, the provenance for detrital sediments in the Levantine basin can be adequately described using 2-end-members. However, in the central Mediterranean, a three-endmember mixing system is required. The three endmember include Saharan Dust, Aegean/Nile, and Libyan Soil, which respectively represents the eolian supply from North Africa, the riverine inputs from the Aegean/Nile areas, and the riverine and shelf-derived fluxes from the Libyan-Tunisian margin. For the first time, robust and consistent evidence is given for important riverine supplies from the Libyan-Tunisian margin into the central Mediterranean during sapropel S1 time in particular. Considerable amounts of detrital materials and freshwater must have been delivered into the EMS through the fossil river/wadi systems, which were activated by intensified African monsoon precipitation. A west-east comparison of Sr-Nd isotope data between core CP10BC and 4 other cores throughout the EMS shows that, such detrital supplies originated mainly from western Libya and Tunisia, and were transported as far eastward as 25°E while being diluted by an increasing Nile contribution. The Nile contribution to the central-Mediterranean detrital sediment fraction appears to have been negligible. Moreover, elemental proxies (Ti/Al, K/Al, Y/Sc, Ce/Ni, and Zr/Cr) reflect concordant changes in the three endmembers at high resolution. These indicate that enhanced precipitation and associated detrital fluxes must have occurred not only from North Africa but also from the northern EMS borderlands. Changes in the Libyan-Tunisian riverine contribution show a close correspondence with hydroclimate evolution of NW Libya on the one hand, and with prominent riverine contribution from the northern EMS borderlands on the other (Wu et al., 2016). Wu, J., Böning, P., Pahnke, K., Tachikawa, K., De Lange, G.J., 2016. Unraveling North-African riverine and eolian contributions to central Mediterranean sediments during Holocene sapropel S1 formation. Quaternary Science reviews 152, 31-48.

Analysis of System Margins on Missions Utilizing Solar Electric Propulsion

NASA Technical Reports Server (NTRS)

Oh, David Y.; Landau, Damon; Randolph, Thomas; Timmerman, Paul; Chase, James; Sims, Jon; Kowalkowski, Theresa

2008-01-01

NASA's Jet Propulsion Laboratory has conducted a study focused on the analysis of appropriate margins for deep space missions using solar electric propulsion (SEP). The purpose of this study is to understand the links between disparate system margins (power, mass, thermal, etc.) and their impact on overall mission performance and robustness. It is determined that the various sources of uncertainty and risk associated with electric propulsion mission design can be summarized into three relatively independent parameters 1) EP Power Margin, 2) Propellant Margin and 3) Duty Cycle Margin. The overall relationship between these parameters and other major sources of uncertainty is presented. A detailed trajectory analysis is conducted to examine the impact that various assumptions related to power, duty cycle, destination, and thruster performance including missed thrust periods have on overall performance. Recommendations are presented for system margins for deep space missions utilizing solar electric propulsion.

Evidence of West Nile virus infection in Nepal.

PubMed

Rutvisuttinunt, Wiriya; Chinnawirotpisan, Piyawan; Klungthong, Chonticha; Shrestha, Sanjaya Kumar; Thapa, Amod Bahadur; Pant, Arjun; Yingst, Samuel L; Yoon, In-Kyu; Fernandez, Stefan; Pavlin, Julie A

2014-11-27

Acute febrile illness is common among those seeking medical care and is frequently treated empirically with the underlying illness remaining undiagnosed in resource-poor countries. A febrile illness study was conducted 2009-2010 to identify known and unknown pathogens circulating in Nepal. Study methods included diagnostic testing and preliminary ELISA screening of acute and convalescent samples for diseases both known and unknown to be circulating in Nepal, including West Nile virus (WNV). The molecular assays including Polymerase Chain Reaction (PCR), Sanger sequencing and ultra deep sequencing on MiSeq Illumina Platform were conducted to further confirm the presence of WNV. The study enrolled 2,046 patients presenting undifferentiated febrile illness with unknown etiology. Sera from 14 out of 2,046 patients were tested positive for west nile virus (WNV) by nested Reverse Transcription-Polymerase Chain Reaction (RT-PCR). Only two out of 14 cases were confirmed for the presence of WNV by sequencing and identified as WNV lineage 1 phylogentically. The two patients were adult males with fever and no neurological symptoms from Kathmandu and Bharatpur, Nepal. Two out of 2,046 serum samples contained fragments of WNV genome resembling WNV lineage 1, which is evidence of the continued spread of WNV which should be considered a possible illness cause in Nepal.

The role of deep-water sedimentary processes in shaping a continental margin: The Northwest Atlantic

USGS Publications Warehouse

Mosher, David C.; Campbell, D.C.; Gardner, J.V.; Piper, D.J.W.; Chaytor, Jason; Rebesco, M.

2017-01-01

The tectonic history of a margin dictates its general shape; however, its geomorphology is generally transformed by deep-sea sedimentary processes. The objective of this study is to show the influences of turbidity currents, contour currents and sediment mass failures on the geomorphology of the deep-water northwestern Atlantic margin (NWAM) between Blake Ridge and Hudson Trough, spanning about 32° of latitude and the shelf edge to the abyssal plain. This assessment is based on new multibeam echosounder data, global bathymetric models and sub-surface geophysical information.The deep-water NWAM is divided into four broad geomorphologic classifications based on their bathymetric shape: graded, above-grade, stepped and out-of-grade. These shapes were created as a function of the balance between sediment accumulation and removal that in turn were related to sedimentary processes and slope-accommodation. This descriptive method of classifying continental margins, while being non-interpretative, is more informative than the conventional continental shelf, slope and rise classification, and better facilitates interpretation concerning dominant sedimentary processes.Areas of the margin dominated by turbidity currents and slope by-pass developed graded slopes. If sediments did not by-pass the slope due to accommodation then an above grade or stepped slope resulted. Geostrophic currents created sedimentary bodies of a variety of forms and positions along the NWAM. Detached drifts form linear, above-grade slopes along their crests from the shelf edge to the deep basin. Plastered drifts formed stepped slope profiles. Sediment mass failure has had a variety of consequences on the margin morphology; large mass-failures created out-of-grade profiles, whereas smaller mass failures tended to remain on the slope and formed above-grade profiles at trough-mouth fans, or nearly graded profiles, such as offshore Cape Fear.

Plio-Quaternary sedimentation in the Mozambique Channel and in the Zambezi Fan

NASA Astrophysics Data System (ADS)

Fierens, Ruth; Droz, Laurence; Toucanne, Samuel; Jorry, Stephan; Raisson, François

2017-04-01

The classical stratigraphic framework stating minimum land-to-sea transfers during periods of high relative sea-level is challenged by marine sedimentary systems in regions where climate (low latitude, monsoon-type) is dominated by the 23-ky cyclicity. Known turbidite systems at the lowest latitudes, like the Nile and Bengal systems (Ducassou et al., 2009; Weber et al., 1997) show that the supply of sediments to the deep oceanic domain could persist during relative high sea-level periods. But turbidite systems at low-latitudes still remain poorly understood. In this work, we use the Zambezi turbidite system as a case study to develop our understanding of the reactivity of deep marine sedimentary systems and land-sea transfers to low-latitude climate variability. The Zambezi Plio-Quaternary turbidite system ( 2000 km long x 500 km wide) is located within the Mozambique Channel (Indian Ocean; 11°-30°S), separating Madagascar from the African continent, in a context of high hydronamic conditions. An extensive dataset acquired strategically along the turbidite system was obtained within the scope of the PAMELA project (scientific project leaded by Ifremer and TOTAL in collaboration with Université de Bretagne Occidentale, Université Rennes 1, Université Pierre and Marie Curie, CNRS et IFPEN) and includes multibeam bathymetry, seismic reflection data and sediment cores. Preliminary results of morphological, seismic and sedimentological study suggest that this turbidite system in the Mozambique Channel is particular: i) The Zambezi Valley currently appears to be dominated by erosional or vacuity process over its entire length, which is observed within the valley as well as on the flanks; ii) Only two restricted zones of tubiditic deposition are identified; iii) The sedimentary record of the last 375 ky shows few turbidites that occurs both during glacial and interglacial periods, with a rate of recurrence of several tens of thousands of years. Additional sedimentological results demonstrate a high diversity in turbidite facies depending on the location in the Zambezi system and the pelagic sediments between these turbidites are carbon-rich and have a low sedimentation rate (average of 2.7 cm/ka). These results imply that multiple controlling factors (sediment supplies, geomorphology, along slope bottom currents inducing possible selective transport of fine particles and impact of climatic and eustatic cycles) impacted the sedimentation and led to the atypical architecture of the Zambezi turbidity system. The PhD thesis of Ruth Fierens is co-funded by TOTAL and IFREMER as part of the PAMELA (Passive Margin Exploration Laboratories) scientific project. Cited references Ducassou et al., 2009. Evolution of the Nile deep-sea turbidite system during the Late Quaternary: influence of climate change on fan sedimentation. Sedimentology 56(7), 2061-2090. Weber et al., 1997. Active growth of the Bengal Fan during sea-level rise and highstand. Geology, 25(4), 315-318.

Deep crustal earthquakes associated with continental rifts

NASA Astrophysics Data System (ADS)

Doser, Diane I.; Yarwood, Dennis R.

1994-01-01

Deep (> 20 km) crustal earthquakes have occurred within or along the margins of at least four continental rift zones. The largest of these deep crustal earthquakes ( M ⩾ 5.0) have strike-slip or oblique-slip mechanisms with T-axes oriented similarly to those associated with shallow normal faulting within the rift zones. The majority of deep crustal earthquakes occur along the rift margins in regions that have cooler, thicker crust. Several deep crustal events, however, occur in regions of high heat flow. These regions also appear to be regions of high strain, a factor that could account for the observed depths. We believe the deep crustal earthquakes represent either the relative motion of rift zones with respect to adjacent stable regions or the propagation of rifting into stable regions.

PAX5 methylation detection by droplet digital PCR for ultra-sensitive deep surgical margins analysis of head and neck squamous cell carcinoma

PubMed Central

Hayashi, Masamichi; Guerrero-Preston, Rafael; Sidransky, David; Koch, Wayne M.

2015-01-01

Molecular deep surgical margin analysis has been shown to predict locoregional recurrences of head and neck squamous cell carcinoma (HNSCC). In order to improve the accuracy and versatility of the analysis, we used a highly tumor-specific methylation marker and highly sensitive detection technology to test DNA from surgical margins. Histologically cancer-negative deep surgical margin samples were prospectively collected from 82 eligible HNSCC surgeries by an imprinting procedure (n=75) and primary tissue collection (n=70). Bisulfite treated DNA from each sample was analyzed by both conventional quantitative methylation-specific polymerase chain reaction (QMSP) and QMSP by droplet digital PCR (ddQMSP) targeting PAX5 gene promoter methylation. The association between the presence of PAX5 methylation and locoregional recurrence free survival (LRFS) was evaluated. PAX5 methylation was found in 68.0% (51/75) of tumors in the imprint samples and 71.4% (50/70) in the primary tissue samples. Among cases which did not have postoperative radiation, (n=31 in imprint samples, n=29 in tissue samples), both conventional QMSP and ddQMSP revealed that PAX5 methylation positive margins was significantly associated with poor LRFS by univariate analysis. In particular, ddQMSP increased detection of the PAX5 marker from 29% to 71% in the non-radiated imprint cases. Also, PAX5 methylated imprint margins were an excellent predictor of poor LRFS (HR=3.89, 95%CI:1.19-17.52, P=0.023) by multivariate analysis. PAX5 methylation appears to be an excellent tumor-specific marker for molecular deep surgical margin analysis of HNSCC. Moreover, the ddQMSP assay displays increased sensitivity for methylation marker detection. PMID:26304463

Long term impacts of combined sewer overflow remediation on water quality and population dynamics of Culex quinquefasciatus, the main urban West Nile virus vector in Atlanta, GA.

PubMed

Lund, Andrea; McMillan, Joseph; Kelly, Rosmarie; Jabbarzadeh, Shirin; Mead, Daniel G; Burkot, Thomas R; Kitron, Uriel; Vazquez-Prokopec, Gonzalo M

2014-02-01

Combined sewers are a significant source of urban water pollution due to periodic discharges into natural streams. Such events (called combined sewer overflows, or CSOs) contribute to the impairment of natural waterways and are associated with increased mosquito productivity and elevated risk of West Nile virus transmission. We investigated the impact of CSOs on water quality and immature mosquito productivity in the city of Atlanta, Georgia, one year before and four years after CSO facility remediation. Water quality (ammonia, phosphate, nitrate and dissolved oxygen concentrations), immature mosquitoes (larvae and pupae), water temperature and rainfall were quantified biweekly between June-October at two urban creeks during 2008-2012. A before-after control-intervention design tested the impact of remediation on mosquito productivity and water quality, whereas generalized linear mixed-effect models quantified the factors explaining the long term impacts of remediation on mosquito productivity. Ammonia and phosphate concentrations and late immature (fourth-instar and pupae) mosquito populations were significantly higher in CSO than in non-CSO creeks, while dissolved oxygen concentrations were lower. Remediation significantly improved water quality estimates (particularly ammonia and dissolved oxygen) and reduced the number of overflows, mosquito productivity and the overall contribution of CSO-affected streams as sources of vectors of West Nile virus. The quality of water in CSOs provided a suitable habitat for immature mosquitoes. Remediation of the CSO facility through the construction of a deep storage tunnel improved water quality indices and reduced the productivity of mosquito species that can serve as vectors of West Nile virus. Copyright © 2013 Elsevier Inc. All rights reserved.

Geomorphological and sedimentary processes of the glacially influenced northwestern Iberian continental margin and abyssal plains

NASA Astrophysics Data System (ADS)

Llave, Estefanía; Jané, Gloria; Maestro, Adolfo; López-Martínez, Jerónimo; Hernández-Molina, F. Javier; Mink, Sandra

2018-07-01

The offshore region of northwestern Iberia offers an opportunity to study the impacts of along-slope processes on the morphology of a glacially influenced continental margin, which has traditionally been conceptually characterised by predominant down-slope sedimentary processes. High-resolution multibeam bathymetry, acoustic backscatter and ultrahigh-resolution seismic reflection profile data are integrated and analysed to describe the present-day and recent geomorphological features and to interpret their associated sedimentary processes. Seventeen large-scale seafloor morphologies and sixteen individual echo types, interpreted as structural features (escarpments, marginal platforms and related fluid escape structures) and depositional and erosional bedforms developed either by the influence of bottom currents (moats, abraded surfaces, sediment waves, contourite drifts and ridges) or by gravitational features (gullies, canyons, slides, channel-levee complexes and submarine fans), are identified for the first time in the study area (spanning 90,000 km2 and water depths of 300 m to 5 km). Different types of slope failures and turbidity currents are mainly observed on the upper and lower slopes and along submarine canyons and deep-sea channels. The middle slope morphologies are mostly determined by the actions of bottom currents (North Atlantic Central Water, Mediterranean Outflow Water, Labrador Sea Water and North Atlantic Deep Water), which thereby define the margin morphologies and favour the reworking and deposition of sediments. The abyssal plains (Biscay and Iberian) are characterised by pelagic deposits and channel-lobe systems (the Cantabrian and Charcot), although several contourite features are also observed at the foot of the slope due to the influence of the deepest water masses (i.e., the North Atlantic Deep Water and Lower Deep Water). This work shows that the study area is the result of Mesozoic to present-day tectonics (e.g. the marginal platforms and structural highs). Therefore, tectonism constitutes a long-term controlling factor, whereas the climate, sediment supply and bottom currents play key roles in the recent short-term architecture and dynamics. Moreover, the recent predominant along-slope sedimentary processes observed in the studied northwestern Iberian Margin represent snapshots of the progressive stages and mixed deep-water system developments of the marginal platforms on passive margins and may provide information for a predictive model of the evolution of other similar margins.

First account on the sedimentological, geochemical and petrophysical record of the Messinian Salinity Crisis in the subsurface of onshore Nile Delta, Egypt.

NASA Astrophysics Data System (ADS)

Leila, Mahmoud; Moscariello, Andrea

2016-04-01

The giant Cenozoic Nile Delta system in the extreme northern part of Egypt occupies the southeastern part of the Eastern Mediterranean Basin and represents the most prolific gas province in Egypt with estimates more than 62 tcf of proven reserves (Niazi and Dahi, 2004). Despite the importance of the Messinian sediments in the Nile Delta hosting excellent petroleum reservoirs and seals (Dolson et al., 2001), they are still poorly studied. A multidisciplinary sedimentological, geochemical and petrophysical study is being carried out to unravel the depositional environment and tectonic setting before, during and after the important Messinian Salinity Crisis (MSC) period in the Eastern Mediterranean, and how this affected the eastern part of the onshore Nile Delta. The Lower Messinian Qawasim Formation consists of high to low-density turbiditic sandstones displaying several vertical stacked patterns of coarsening and fining upwards trends reflecting different pulses of sedimentation suggesting a sedimentation in a submarine fan developed at the base of shelf slope. The deeply incised valley infill, dating the Upper Messinian consists of the Abu Madi Formation made of lowstand braided and meandering fluvial sandstone interbedded with fine-grained floodplain sandstones and siltstones. The base of this unit is erosional and contains large mud clasts embedded in a fine-grained matrix. The Upper Miocene lowstand fluvial sandstones are capped by estuarine fine-grained cross laminated sandstones, siltstones/mudstones followed by an open marine mudstones of the Early Pliocene Kafr El-Sheikh Formation representing the end of the MSC and the subsequent transgression episode after the re-establishment of the connection between the Mediterranean and the Atlantic Ocean. Both the Qawasim and Abu Madi Formations display similar geochemical fingerprints from the clastic components. Recycled Cretaceous and Eocene sedimentary and granodioritic to intermediate igneous rocks located in the Red Sea hills are considered to be the protolithites for the Miocene clastic rock. The depositional environment and diagenetic alterations enormously influenced the resulting composition and reservoir quality of the Miocene sandstones. Within the fluvial environmental conditions, early mechanical clay infiltration occurred that completely modified the original texture and porosity of the fluvial sandstones. In this unit the frequent transformation of feldspars into authigenic kaolinite, likely enhanced by favourable climatic conditions, also occurred. In general, the fluvial sandstones were subjected to more intense weathering than the turbiditic sandstones resulting in higher alteration indices (CIA and PIA). The sedimentological and geochemical data suggest that both depositional environments developed at the transition between the Lower Messinian and Early Pliocene, occurred in a passive margin setting likely at the edge of a shelf scarp, where the drastic drop in sea level resulted in the incision of a deep valley subsequently filled up during the Zanclean (?) transgression. References Niazi, M., Dahi, M., 2004. Unexplored giant sandstone features in ultra- deepwater, West Mediterranean, Egypt. In: American Association of Petroleum Geologists International Conference: October 24- 27, 2004; Cancun, Mexico. Dolson, J., Shann, M., Matbouly, S., Harwood, C., Rashed, R., Hammouda, H., 2001. The Petroleum Potential of Egypt, AAPG Memoir 74: 453- 482.

Limitations of microbial hydrocarbon degradation at the Amon mud volcano (Nile deep-sea fan)

NASA Astrophysics Data System (ADS)

Felden, J.; Lichtschlag, A.; Wenzhöfer, F.; de Beer, D.; Feseker, T.; Pop Ristova, P.; de Lange, G.; Boetius, A.

2013-05-01

The Amon mud volcano (MV), located at 1250 m water depth on the Nile deep-sea fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amon MV center in the presence of sulfate and hydrocarbons in the seeping subsurface fluids. By comparing spatial and temporal patterns of in situ biogeochemical fluxes, temperature gradients, pore water composition, and microbial activities over 3 yr, we investigated why the activity of anaerobic hydrocarbon degraders can be low despite high energy supplies. We found that the central dome of the Amon MV, as well as a lateral mud flow at its base, showed signs of recent exposure of hot subsurface muds lacking active hydrocarbon degrading communities. In these highly disturbed areas, anaerobic degradation of methane was less than 2% of the methane flux. Rather high oxygen consumption rates compared to low sulfide production suggest a faster development of more rapidly growing aerobic hydrocarbon degraders in highly disturbed areas. In contrast, the more stabilized muds surrounding the central gas and fluid conduits hosted active anaerobic hydrocarbon-degrading microbial communities. The low microbial activity in the hydrocarbon-vented areas of Amon MV is thus a consequence of kinetic limitations by heat and mud expulsion, whereas most of the outer MV area is limited by hydrocarbon transport.

Stratal stacking patterns and tectono-sedimentary evolution of hyperextended magma-poor rifted margins

NASA Astrophysics Data System (ADS)

Ribes, C.; Gillard, M.; Epin, M. E.; Ghienne, J. F.; Manatschal, G.; Karner, G. D.; Johnson, C. A.

2016-12-01

Research on the formation and evolution of deep-water rifted margins has undergone a major paradigm shift in recent years. An increasing number of studies of present-day and fossil rifted margins allow us to identify and characterize the structural architecture of the most distal parts of rifted margins, the so-called hyperextended, magma-poor rifted margins. However, at present, little is known about the depositional environments, sedimentary facies, stacking patterns, subsidence and thermal history within these domains. In this context, characterizing the stratal stacking patterns and understanding their spatial and temporal evolution is a new challenge. The major difficulty comes from the fact that the observed stratigraphic geometries and facies relationships are a result of the complex interplay between sediment supply and available accommodation, which is controlled by not only the regional generation of accommodation, but also by local tectono-magmatic processes. These parameters are poorly constrained or even sufficiently known in these tectonic settings. Indeed, the complex structural evolution of hyperextended magma-poor rifted margins, including the development of poly-phase in-sequence and out of sequence extensional detachment faults and associated mantle exhumation and magmatic activity, can generate complex accommodation patterns over a highly structured top basement. The presentation summarizes early results concerning the controlling parameters on ultra-deep water stratigraphic stacking patterns and to provide a conceptual framework. This observation-driven approach combines fieldwork from fossil Alpine Tethys margins exposed in the Alps and the analysis of seismic reflection data from present-day deep water rifted margins such as the Australian-Antarctic, East India and Iberia-Newfoundland margins.

Prediction of villages at risk for filariasis transmission in the Nile Delta using remote sensing and geographic information system technologies.

PubMed

Hassan, A N; Beck, L R; Dister, S

1998-04-01

Remote sensing and geographic information system (GIS) technologies were used to discriminate between 130 villages, in the Nile Delta, at high and low risk for filariasis, as defined by microfilarial prevalence. Landsat Thematic Mapper (TM) data were digitally processed to generate a map of landcover as well as spectral indices such as NDVI and moisture index. A Tasseled Cap transformation was also carried out on the TM data which produced three more indices: brightness, greenness and wetness. GIS functions were used to extract information on landcover and spectral indices within one km buffers around the study villages. The relationship between satellite data and prevalence was investigated using discriminant analysis. The analysis indicated that the most important landscape elements associated with prevalence were water and marginal vegetation, while wetness and moisture index were the most important indices. Discriminant functions generated for these variables were able to correctly predict 80% and 74% of high and low prevalence villages, respectively, with an overall accuracy of 77%. The present approach provides a promising tool for regional filariasis surveillance and helps direct control efforts.

Embryonic wound healing by apical contraction and ingression in Xenopus laevis.

PubMed

Davidson, Lance A; Ezin, Akouavi M; Keller, Ray

2002-11-01

We have characterized excisional wounds in the animal cap of early embryos of the frog Xenopus laevis and found that these wounds close accompanied by three distinct processes: (1) the assembly of an actin purse-string in the epithelial cells at the wound margin, (2) contraction and ingression of exposed deep cells, and (3) protrusive activity of epithelial cells at the margin. Microsurgical manipulation allowing fine control over the area and depth of the wound combined with videomicroscopy and confocal analysis enabled us to describe the kinematics and challenge the mechanics of the closing wound. Full closure typically occurs only when the deep, mesenchymal cell-layer of the ectoderm is left intact; in contrast, when deep cells are removed along with the superficial, epithelial cell-layer of the ectoderm, wounds do not close. Actin localizes to the superficial epithelial cell-layer at the wound margin immediately after wounding and forms a contiguous "purse-string" in those cells within 15 min. However, manipulation and closure kinematics of shaped wounds and microsurgical cuts made through the purse-string rule out a major force-generating role for the purse-string. Further analysis of the cell behaviors within the wound show that deep, mesenchymal cells contract their apical surfaces and ingress from the exposed surface. High resolution time-lapse sequences of cells at the leading edge of the wound show that these cells undergo protrusive activity only during the final phases of wound closure as the ectoderm reseals. We propose that assembly of the actin purse-string works to organize and maintain the epithelial sheet at the wound margin, that contraction and ingression of deep cells pulls the wound margins together, and that protrusive activity of epithelial cells at the wound margin reseals the ectoderm and re-establishes tissue integrity during wound healing in the Xenopus embryonic ectoderm. Copyright 2002 Wiley-Liss, Inc.

Flow cytometric single cell analysis reveals heterogeneity between adipose depots

PubMed Central

Boumelhem, Badwi B.; Assinder, Stephen J.; Bell-Anderson, Kim S.; Fraser, Stuart T.

2017-01-01

ABSTRACT Understanding adipose tissue heterogeneity is hindered by the paucity of methods to analyze mature adipocytes at the single cell level. Here, we report a system for analyzing live adipocytes from different adipose depots in the adult mouse. Single cell suspensions of buoyant adipocytes were separated from the stromal vascular fraction and analyzed by flow cytometry. Compared to other lipophilic dyes, Nile Red uptake effectively distinguished adipocyte populations. Nile Red fluorescence increased with adipocyte size and granularity and could be combined with MitoTracker® Deep Red or fluorescent antibody labeling to further dissect adipose populations. Epicardial adipocytes exhibited the least mitochondrial membrane depolarization and highest fatty-acid translocase CD36 surface expression. In contrast, brown adipocytes showed low surface CD36 expression. Pregnancy resulted in reduced mitochondrial membrane depolarisation and increased CD36 surface expression in brown and epicardial adipocyte populations respectively. Our protocol revealed unreported heterogeneity between adipose depots and highlights the utility of flow cytometry for screening adipocytes at the single cell level. PMID:28453382

Identification of Abnormal System Noise Temperature Patterns in Deep Space Network Antennas Using Neural Network Trained Fuzzy Logic

NASA Technical Reports Server (NTRS)

Lu, Thomas; Pham, Timothy; Liao, Jason

2011-01-01

This paper presents the development of a fuzzy logic function trained by an artificial neural network to classify the system noise temperature (SNT) of antennas in the NASA Deep Space Network (DSN). The SNT data were classified into normal, marginal, and abnormal classes. The irregular SNT pattern was further correlated with link margin and weather data. A reasonably good correlation is detected among high SNT, low link margin and the effect of bad weather; however we also saw some unexpected non-correlations which merit further study in the future.

Geomorphology of the Eastern North American Continental Margin: the role of deep sea sedimentation processes

NASA Astrophysics Data System (ADS)

Mosher, D. C.; Campbell, C.; Piper, D.; Chaytor, J. D.; Gardner, J. V.; Rebesco, M.

2016-12-01

Deep-sea sedimentation processes impart a fundamental control on the morphology of the western North Atlantic continental margin from Blake Spur to Hudson Strait. This fact is illustrated by the variable patterns of cross-margin gradients that are based on extensive new multibeam echo-sounder data in concert with subbottom profiler and seismic reflection data. Most of the continental margin has a steep (>3o) upper slope down to 1500 to 2500 m and then a gradual middle and lower slope with a general concave upward shape There is a constant interplay of deep sea sedimentation processes, but the general morphology is dictated by the dominant one. Erosion by off-shelf sediment transport in turbidity currents creating channels, gullies and canyons creates the steep upper slope. These gullies and canyons amalgamate to form singular channels that are conduits to the abyssal plain. This process results in a general seaward flattening of gradients, producing an exponentially decaying slope profile. Comparatively, sediment mass failure produces steeper upper slopes due to head scarp development and a wedging architecture to the lower slope as deposits thin in the downslope direction. This process results in either a two-segment slope, and/or a significant downslope gradient change where MTDs pinch out. Large sediment bodies deposited by contour-following currents are developed all along the margin. Blake Ridge, Sackville Spur, and Hamilton Spur are large detached drifts on disparate parts of the margin. Along their crests, they form a linear profile from the shelf to abyssal plain. Deeper portions of the US continental margin are dominated by the Chesapeake Drift and Hatteras Outer Ridge; both plastered elongate mounded drifts. Farther north, particularly on the Grand Banks margin, are plastered and separated drifts. These drifts tend to form bathymetric steps in profile, where they onlap the margin. Stacked drifts create several steps. Turbidites of the abyssal plain onlap the lowermost drift creating a significant gradient change at this juncture. Understanding the geomorphological consequences of deep sea sedimentation processes is important to extended continental shelf mapping, for example, in which gradient change is a critical metric.

Deep sea sedimentation processes and geomorphology: Northwest Atlantic continental margin

NASA Astrophysics Data System (ADS)

Mosher, David; Campbell, Calvin; Gardner, Jim; Chaytor, Jason; Piper, David; Rebesco, Michele

2017-04-01

Deep-sea sedimentation processes impart a fundamental control on the morphology of the western North Atlantic continental margin from Blake Spur to Hudson Strait. This fact is illustrated by the variable patterns of cross-margin gradients that are based on extensive new multibeam echo-sounder data informed by subbottom profiler and seismic reflection data. Erosion by off-shelf sediment transport in turbidity currents creates gullies, canyons and channels and a steep upper slope. Amalgamation of these conduits produces singular channels and turbidite fan complexes on the lower slope, flattening slope-profile gradients. The effect is an exponentially decaying "graded" slope profile. Comparatively, sediment mass failure produces steeper upper slopes due to head scarp development and a wedging architecture to the lower slope as deposits thin in the downslope direction. This process results in either a "stepped" slope, and/or a significant downslope gradient change where MTDs pinch out. Large drift deposits created by geostrophic currents are developed all along the margin. Blake Ridge, Sackville Spur, and Hamilton Spur are large detached drifts on disparate parts of the margin. They form a linear "above grade" profile along their crests from the shelf to abyssal plain. Deeper portions of the US continental margin are dominated by the Chesapeake Drift and Hatteras Outer Ridge; both plastered elongate mounded drifts. Farther north, particularly on the Grand Banks margin, are plastered and separated drifts. These drifts form "stepped" slope profiles, where they onlap the margin. Trough-mouth fan complexes become more common along the margin with increasing latitude. Sediment deposition and retention, particularly those dominated by glacigenic debris flows, characterize these segments producing an "above grade" slope profile. Understanding these geomorphological consequences of deep sea sedimentation processes is important to extended continental shelf mapping in which gradients and gradient change is a critical metric.

Sinai peninsula taken by the STS-112 crew

NASA Image and Video Library

2002-10-08

STS112-702-002 (7-18 October 2002) --- Egypt's triangular Sinai Peninsula lies in the center of this view, photographed from the Space Shuttle Atlantis, with the dark greens of the Nile delta lower right. In this southwesterly view, the Red Sea, with its characteristic parallel coastlines, stretches toward the top. At the bottom of the image, the Suez Canal appears as an irregular line joining the Red Sea to the Mediterranean Sea (lower left). The Dead Sea in central Israel, with its light blue salt ponds at the south end, appears on the left margin.

The T-Reflection and the deep crustal structure of the Vøring Margin offshore Mid-Norway

NASA Astrophysics Data System (ADS)

Abdelmalak, M. M.; Faleide, J. I.; Planke, S.; Gernigon, L.; Zastrozhnov, D.; Shephard, G. E.; Myklebust, R.

2017-12-01

Volcanic passive margins are characterized by massive occurrence of mafic extrusive and intrusive rocks, before and during plate breakup, playing major role in determining the evolution pattern and the deep structure of magma-rich margins. Deep seismic reflection data frequently provide imaging of strong continuous reflections in the middle/lower crust. In this context, we have completed a detailed 2D seismic interpretation of the deep crustal structure of the Vøring volcanic margin, offshore mid-Norway, where high-quality seismic data allow the identification of high-amplitude reflections, locally referred to as the T-Reflection (TR). Using the dense seismic grid we have mapped the top of the TR in order to compare it with filtered Bouguer gravity anomalies and seismic refraction data. The TR is identified between 7 and 10 s. Sometimes it consists of one single smooth reflection. However, it is frequently associated with a set of rough multiple reflections displaying discontinuous segments with varying geometries, amplitude and contact relationships. The TR seems to be connected to deep sill networks and locally located at the continuation of basement high structures or terminates over fractures and faults. The spatial correlation between the filtered positive Bouguer gravity anomalies and the TR indicates that the latter represents a high impedance boundary contrast associated with a high-density/velocity body. Within an uncertainty of ± 2.5 km, the depth of the mapped TR is found to correspond to the depth of the top of the Lower Crustal Body (LCB), characterized by high P-wave velocities (>7 km/s), in 50% of the outer Vøring Margin areas, whereas different depths between the TR and the top LCB are estimated for the remaining areas. We present a tectonic scenario, where a large part of the deep structure could be composed of preserved upper continental basement and middle to lower crustal lenses of inherited and intruded high-grade metamorphic rocks. Deep intrusions into the faulted crustal blocks are responsible for the rough character of the TR, whereas intrusions into the lower crust and detachment faults are likely responsible for its smoother appearance. Deep magma intrusions can be responsible for metamorphic processes leading to an increased velocity of the lower crust of more than 7 km/s.

Palaeogeographic implications of the Messinian surface in the Valencia trough, northwestern Mediterranean Sea

NASA Astrophysics Data System (ADS)

Escutia, C.; Maldonado, A.

1992-03-01

Sparker (3000 J and 8000 J) and multichannel seismic reflection profiles across the Valencia trough show a Messinian unconformity incised by numerous valleys. The main feature of this surface is a large valley that generally underlies the present Valencia valley and is deeply entrenched into the Miocene deposits. The size of this palaeo-valley ranges from 0.5 km wide and 15-100 m deep at its western end, to 1.6-2.8 km wide and 200-250 m deep downstream. An important tributary system is observed, with a main canyon (6-8 km wide and 150-200 m deep) draining the Ebro margin, as well as many other smaller valleys draining the Catalan and Balearic margins. Downstream, other tributaries underlie the present canyons of the Catalan margin. The location of the tributary system is controlled by the Early Miocene rift structures. The relief of the Messinian surface is affected by post-Miocene deformation that results from salt diapirism, extensional faulting and related volcanism. Late Neogene to Quaternary volcanic edifices cut the Messinian surface and coincide with large residual magnetic anomalies. Lower Pliocene to Quaternary salt diapirism in the abyssal plain north of Menorca has created a series of structural highs. Between these highs are deep interdiapiric troughs or basins that have become sediment depocentres during the Plio-Quaternary. The complex network of erosional valleys from the Valencia trough continental margin demonstrates that the valley system in the basin was not related to the refilling of the Mediterranean, but to the Iberian and Balearic margin palaeodrainage that developed during the Messinian desiccation. The presence of at least three erosional unconformities suggests that there were alternating periods of flooding and retreat of Atlantic water during Messinian time. The Messinian subaerial margin with erosional valleys contrasts sharply with the Pliocene-Quaternary marine margin with progradational turbidite systems.

Numerical experiments of volcanic dominated rifts and passive margins

NASA Astrophysics Data System (ADS)

Korchinski, Megan; Teyssier, Christian; Rey, Patrice; Whitney, Donna; Mondy, Luke

2017-04-01

Continental rifting is driven by plate tectonic forces (passive rifting), thermal thinning of the lithosphere over a hotspot (active rifting), or a combination of the two. Successful rifts develop into passive margins where pre-drift stretching is accompanied by normal faulting, clastic sedimentation, and various degrees of magmatism. The structure of volcanic passive margins (VPM) differs substantially from margins that are dominated by sedimentation. VPMs are typically narrow, with a lower continental crust that is intruded by magma and can flow as a low-viscosity layer. To investigate the role of the deep crust in the early development of VPMs, we have developed a suite of 2D thermomechanical numerical experiments (Underworld code) in which the density and viscosity of the deep crust and the density of the rift basin fill are systematically varied. Our experiments show that, for a given rifting velocity, the viscosity of the deep crust and the density of the rift basin fill exert primary controls on early VPM development. The viscosity of the deep crust controls the degree to which the shallow crust undergoes localised faulting or distributed thinning. A weak deep crust localises rifting and is efficiently exhumed to the near-surface, whereas a strong deep crust distributes shallow crust extension and remains buried. A high density rift basin fill results in gravitational loading and increased subsidence rate in cases in which the viscosity of the deep crust is sufficiently low to allow that layer to be displaced by the sinking basin fill. At the limit, a low viscosity deep crust overlain by a thick basalt-dominated fill generates a gravitational instability, with a drip of cool basalt that sinks and ponds at the Moho. Experiment results indicate that the deep crust plays a critical role in the dynamic development of volcanic dominated rifts and passive margins. During rifting, the deep continental crust is heated and readily responds to solicitations of the shallow crust (rooting of normal faults, exhumation of the deep crust in normal fault footwalls). Gravitational instabilities caused by high density rift infill similar to those observed in our numerical experiments may be present in the Mesoproterozoic ( 1100 Ma) North American Midcontinent Rift System (MRS). The MRS is a failed rift that is filled with >20 km of dominantly basaltic volcanic deposits, and therefore represents an end member VPM (high density basin fill) where the initial structure of a pre-drift VPM is preserved. Magmatism occurred in two pulses over <15 Ma involving deep mantle melting first (>150 km), then shallow melting (40-70 km). Post-rift subsidence accumulated up to 10 km of clastic sediments in the center of the basin. Evidence of cool, dense rocks sinking into a low-viscosity deep crust as predicted in our numerical experiments may be present in the western arm of the MRS, where crustal density analyses suggest the presence of dense bodies (eclogite) at the base of the crust.

Limitations of microbial hydrocarbon degradation at the Amon Mud Volcano (Nile Deep Sea Fan)

NASA Astrophysics Data System (ADS)

Felden, J.; Lichtschlag, A.; Wenzhöfer, F.; de Beer, D.; Feseker, T.; Pop Ristova, P.; de Lange, G.; Boetius, A.

2013-01-01

The Amon mud volcano (MV), located at 1250 m water depth on the Nile Deep Sea Fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amon MV center in the presence of sulphate and hydrocarbons in the seeping subsurface fluids. By comparing spatial and temporal patterns of in situ biogeochemical fluxes, temperature gradients, pore water composition and microbial activities over three years, we investigated why the activity of anaerobic hydrocarbon degraders can be low despite high energy supplies. We found that the central dome of the Amon MV, as well as a lateral mud flow at its base, showed signs of recent exposure of hot subsurface muds lacking active hydrocarbon degrading communities. In these highly disturbed areas, anaerobic degradation of methane was less than 2% of the methane flux. Rather high oxygen consumption rates compared to low sulphide production suggest a faster development of more rapidly growing aerobic hydrocarbon degraders in highly disturbed areas. In contrast, the more stabilized muds surrounding the central gas and fluid conduits hosted active anaerobic hydrocarbon-degrading microbial communities. Furthermore, within three years, cell numbers and hydrocarbon degrading activity increased at the gas-seeping sites. The low microbial activity in the hydrocarbon-vented areas of Amon mud volcano is thus a consequence of kinetic limitations by heat and mud expulsion, whereas most of the outer mud volcano area is limited by hydrocarbon transport.

76 FR 33136 - IFR Altitudes; Miscellaneous Amendments

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-08

.......... Chicago Heights, IL VORTAC....... *Niles, IL FIX 2500 *3500--MRA *3000--MCA Niles, IL FIX, N BND *Niles, IL FIX **Laird, IL FIX......... 3400 *3500--MRA **2600--MCA Laird, IL FIX, S BND Laird, IL FIX Thorr... IN PART....... Bebee, IL FIX *Niles, IL FIX 3400 *3500--MRA *3000--MCA Niles, IL FIX, N BND *Niles...

The long-term evolution of the Congo deep-sea fan: A basin-wide view of the interaction between a giant submarine fan and a mature passive margin (ZaiAngo project)

NASA Astrophysics Data System (ADS)

Anka, Zahie; Séranne, Michel; Lopez, Michel; Scheck-Wenderoth, Magdalena; Savoye, Bruno

2009-05-01

We have integrated the relatively unknown distal domains of the Lower Congo basin, where the main depocenters of the Congo submarine fan are located, with the better-constrained successions on the shelf and upper slope, through the analysis of thousands of km of 2D seismic reflection profiles off-shore the Congo-Angola passive margin. The basin architecture is depicted by two ca. 800-km-long regional cross sections through the northern (Congo) and southern (Angola) margin. A large unit deposited basinward of the Aptian salt limit is likely to be the abyssal-plain equivalent of the upper-Cretaceous carbonate shelf that characterized the first post-rift deposits in West-equatorial African margins. A latest-Turonian shelf-deepening event is recorded in the abyssal plain as a long period (Coniacian-Eocene) of condensed sedimentation and basin starvation. The onset of the giant Tertiary Congo deep-sea fan in early Oligocene following this event reactivates the abyssal plain as the main depocenter of the basin. The time-space partitioning of sedimentation within the deep-sea fan results from the interplay among increasing sediment supply, margin uplift, rise of the Angola salt ridge, and canyon incision throughout the Neogene. Oligocene-early Miocene turbidite sedimentation occurs mainly in NW-SE grabens and ponded inter-diapir basins on the southern margin (Angola). Seaward tilting of the margin and downslope salt withdrawal activates the up-building of the Angola escarpment, which leads to a northward (Congo) shift of the transfer zones during late Miocene. Around the Miocene-Pliocene boundary, the incision of the Congo submarine canyon confines the turbidite flows and drives a general basinward progradation of the submarine fan into the abyssal plain The slope deposition is dominated by fine-grained hemipelagic deposits ever since. Results from this work contribute to better understand the signature in the ultra-deep deposits of processes acting on the continental margin as well as the basin-wide sediment redistribution in areas of high river input.

OCT structure, COB location and magmatic type of the S Angolan & SE Brazilian margins from integrated quantitative analysis of deep seismic reflection and gravity anomaly data

NASA Astrophysics Data System (ADS)

Cowie, Leanne; Kusznir, Nick; Horn, Brian

2014-05-01

Integrated quantitative analysis using deep seismic reflection data and gravity inversion have been applied to the S Angolan and SE Brazilian margins to determine OCT structure, COB location and magmatic type. Knowledge of these margin parameters are of critical importance for understanding rifted continental margin formation processes and in evaluating petroleum systems in deep-water frontier oil and gas exploration. The OCT structure, COB location and magmatic type of the S Angolan and SE Brazilian rifted continental margins are much debated; exhumed and serpentinised mantle have been reported at these margins. Gravity anomaly inversion, incorporating a lithosphere thermal gravity anomaly correction, has been used to determine Moho depth, crustal basement thickness and continental lithosphere thinning. Residual Depth Anomaly (RDA) analysis has been used to investigate OCT bathymetric anomalies with respect to expected oceanic bathymetries and subsidence analysis has been used to determine the distribution of continental lithosphere thinning. These techniques have been validated for profiles Lusigal 12 and ISE-01 on the Iberian margin. In addition a joint inversion technique using deep seismic reflection and gravity anomaly data has been applied to the ION-GXT BS1-575 SE Brazil and ION-GXT CS1-2400 S Angola deep seismic reflection lines. The joint inversion method solves for coincident seismic and gravity Moho in the time domain and calculates the lateral variations in crustal basement densities and velocities along the seismic profiles. Gravity inversion, RDA and subsidence analysis along the ION-GXT BS1-575 profile, which crosses the Sao Paulo Plateau and Florianopolis Ridge of the SE Brazilian margin, predict the COB to be located SE of the Florianopolis Ridge. Integrated quantitative analysis shows no evidence for exhumed mantle on this margin profile. The joint inversion technique predicts oceanic crustal thicknesses of between 7 and 8 km thickness with normal oceanic basement seismic velocities and densities. Beneath the Sao Paulo Plateau and Florianopolis Ridge, joint inversion predicts crustal basement thicknesses between 10-15km with high values of basement density and seismic velocities under the Sao Paulo Plateau which are interpreted as indicating a significant magmatic component within the crustal basement. The Sao Paulo Plateau and Florianopolis Ridge are separated by a thin region of crustal basement beneath the salt interpreted as a regional transtensional structure. Sediment corrected RDAs and gravity derived "synthetic" RDAs are of a similar magnitude on oceanic crust, implying negligible mantle dynamic topography. Gravity inversion, RDA and subsidence analysis along the S Angolan ION-GXT CS1-2400 profile suggests that exhumed mantle, corresponding to a magma poor margin, is absent..The thickness of earliest oceanic crust, derived from gravity and deep seismic reflection data, is approximately 7km consistent with the global average oceanic crustal thicknesses. The joint inversion predicts a small difference between oceanic and continental crustal basement density and seismic velocity, with the change in basement density and velocity corresponding to the COB independently determined from RDA and subsidence analysis. The difference between the sediment corrected RDA and that predicted from gravity inversion crustal thickness variation implies that this margin is experiencing approximately 500m of anomalous uplift attributed to mantle dynamic uplift.

Residual corneal stroma in big-bubble deep anterior lamellar keratoplasty: a histological study in eye-bank corneas.

PubMed

McKee, Hamish D; Irion, Luciane C D; Carley, Fiona M; Jhanji, Vishal; Brahma, Arun K

2011-10-01

To determine if residual corneal stroma remains on the recipient posterior lamella in big-bubble deep anterior lamellar keratoplasty (DALK). Pneumodissection using the big-bubble technique was carried out on eye-bank corneas mounted on an artificial anterior chamber. Samples that had a successful big-bubble formation were sent for histological evaluation to determine if any residual stroma remained on the Descemet membrane (DM). Big-bubble formation was achieved in 32 donor corneas. Two distinct types of big-bubble were seen: the bubble had either a white margin (30 corneas) or a clear margin (two corneas). The posterior lamellae of all the white margin corneas showed residual stroma on DM with a mean central thickness of 7.0 μm (range 2.6-17.4 μm). The clear margin corneas showed no residual stroma on DM. It should no longer be assumed that big-bubble DALK, where the bubble has a white margin, routinely bares DM. True baring of DM may only occur with the less commonly seen clear margin bubble.

Passive recording of an active transform, an example from the Levant continental margin and the Dead Sea Fault

NASA Astrophysics Data System (ADS)

Lang, Guy; Lazar, Michael; Schattner, Uri

2017-04-01

Transform faults accommodate lateral motion between two adjacent plates. Records of plate motion and consequent boundary development on land is, at times, scarce and limited to structures along the fault axis. Investigation of a passive continental margin adjacent to the plate boundary might broaden the scope and provide estimates for its structural development. To examine this hypothesis, we analyzed depth and time migrated 3D seismic data together with four boreholes located along the southern Levant continental margin, ca. 100 Km from the continental Dead Sea fault (DSF). The analysis focus on the Plio-Pleistocene sequence, a key period in the development of the DSF. It includes formation of structural maps, stacking pattern investigation and calculation of sedimentation rates based on decompacted 3D depth data. These, in turn, enabled the reconstruction of margin development. This includes Messinian-earliest Zanclean NNE-SSW sinistral strike-slip faulting followed by Zanclean-Late Gelasian syn-depositional folding striking in the same direction. Abrupt change is marked by the Top Gelasian surface that shows indications of regional mass slumping. Successive Mid-Late Pleistocene progradation marks a basinward shift of the depocenter. Progradation controls margin sedimentation rates during the mid-late Pleistocene. These were found to increase throughout the whole Plio-Pleistocene, in contrast to reported sediment discharge from the Nile, which was shown to decrease after the Gelasian. Correlations to onshore findings, suggest that the continental margin records strain localization on the DSF during the Pliocene-Gelasian. This trend peaked at 1.8 Ma when short wavelength strain ceased along the margin, and differential subsidence commenced basinwards. This is attributed to consequent deepening of the DSF plate boundary.

Holocene-Pleistocene Environmental Changes in Eastern Mediterranean Sediments: Foraminiferal and Geochemical Approach

NASA Astrophysics Data System (ADS)

Sinoussy Mohamed, K. S., Jr.; Ibrahim, M. I. A.; Moustafa, A. R.; Abd Elkarim, M. R.; Shreadah, M. M. A.

2014-12-01

The present study is based on gravity core sediment samples from the Eastern Mediterranean Sea located in 32° 20' 55" N and 31° 47' 79" E, in front of the Nile Delta Fan taken during METEOR cruise M70b (October 2006). The core is gravity one (St#822), 4.5 m long, and in 1089 m water depth. The study of benthic and planktic foraminifera is used to determine the microhabitat of the bottom sediments during warm and cold periods. Sapropels S1, S3 and S4 are encountered in the studied gravity core sample from the eastern Mediterranean. The sapropel layers S1, S3 and S4 were deposited during interglacial periods, characterized by a low foraminiferal numbers, reflecting eutrophic conditions. Glacial periods are characterized by high foraminiferal numbers due probably to an enhanced glacial productivity. Sapropel layers are distinguished by increase of Fe, TOC% (TOC%≥ 1.2%) and decrease of Ca concentrations as a result of the Blue Nile suspended particulate matter discharge during summer monsoon. Clay content increases at the sapropel depths that indicate an increase in the terrigenous input derived from the weathering of Ethiopian basalts. Temporal distribution of planktic and benthic foraminifera in the Nile deep sea fan sediments besides geochemical charcterization, palaeohydrological fluctuations, palaeoenvironment and microhabitat of foraminifera were reconstructed for the last 100000 years including glacial and interglacial periods. Formation of the Sapropel layers are synchronized with the decreasing of δ18O which means that the Mediterranean Sea received high amount of fresh water from the Nile river discharge. Clay content, TOC%, Ca-Fe cycles, oxygen and carbon isotopes and planktic foraminifera document the pluvial and arid periods throughout the 100000 years and define clearly the contributions of terrigenous and TOC% in the sapropel layers. Infauna/epifauna ratio and benthic foraminifera assemblages were used to reconstruct the microhabitat of the sea bottom during sapropel and cold periods.

Primary Evaporites for the Messinian Salinity Crisis: the shallow gypsum vs. deep dolomite formation paradox solved

NASA Astrophysics Data System (ADS)

De Lange, Gert J.; Krijgsman, Wout

2014-05-01

The Messinian Salinity Crisis (MSC) is a dramatic event that took place ~ 5.9 Ma ago, and resulted in the deposition of 0.3-3 km thick evaporites at the Mediterranean seafloor. A considerable and long-lasting controversy existed on the modes of their formation. During the CIESM Almeria Workshop a consensus was reached on several aspects. In addition, remaining issues to be solved were identified, such as for the observed shallow gypsum versus deep dolostone deposits for the early phase of MSC. The onset of MSC is marked by deposition of gypsum/sapropel-like alternations, thought to relate to arid/humid climate conditions. Gypsum precipitation only occurred at marginal settings, while dolomite containing rocks have been reported from deeper settings. A range of potential explanations have been reported, most of which cannot satisfactorily explain all observations. Biogeochemical processes during MSC are poorly understood and commonly neglected. These may, however, explain that different deposits formed in shallow versus deep environments without needing exceptional physical boundary conditions for each. We present here a unifying mechanism in which gypsum formation occurs at all shallow water depths but its preservation is mostly limited to shallow sedimentary settings. In contrast, ongoing anoxic organic matter (OM) degradation processes in the deep basin result in the formation of dolomite. Gypsum precipitation in evaporating seawater takes place at 3-7 times concentrated seawater; seawater is always largely oversaturated relative to dolomite but its formation is thought to be inhibited by the presence of dissolved sulphate. Thus the conditions for formation of gypsum exclude those for the formation of dolomite and vice versa. Another process that links the saturation states of gypsum and dolomite is that of OM degradation by sulphate reduction. In stagnant deep water, oxygen is rapidly depleted through OM degradation, then sulphate becomes the main oxidant for OM mineralization, thus reducing the deep-water sulphate content. In addition, considerable amounts of dissolved carbonate are formed. This means that low-sulphate conditions as for MSC deepwater, i.e. unfavorable conditions for gypsum formation, always coincide with anoxic, i.e. oxygen-free conditions. Thus one would expect a bath-tub rim of gypsum at all shallow depths, but gypsum appears mainly at silled marginal basins. However, a thick package of heavy gypsum on top of more liquid mud in a marginal/slope setting is highly unstable, thus any physical disturbance such as tectonic activity or sea-level change, would easily lead to downslope transport of such marginal gypsum deposits. The absence of gypsum and the presence of erosional unconformities at the sill-less Mediterranean passive margins concord to such removal mechanism. In addition, large-scale re-sedimentation of gypsum has also been found for deep Messinian settings in the Northern Apennines and Sicily. Only at those marginal settings that were silled, the marginal gypsum deposits have been preserved. Including the dynamic biogeochemical processes in the thusfar static interpretations of evaporite formation mechanisms can thus account for the paradoxal, isochronous formation of shallow gypsum and deep-dolomite during the early MSC (1). (1) De Lange G.J. and Krijgsman W. (2010) Mar. Geol. 275, 273-277.

First images of the crustal structure across the central Algerian margin, off Tipaza (West Algiers) from deep penetrating seismic data: new information to constrain the opening of the Algerian basin

NASA Astrophysics Data System (ADS)

Leprêtre, A.; Deverchere, J.; Klingelhoefer, F.; Graindorge, D.; Schnurle, P.; Yelles, K.; Bracene, R.

2011-12-01

The origin of the Algerian margin remains one of the key questions still unresolved in the Western Mediterranean sea. This is related to the unknown nature and kinematics of this Neogene basin. Whereas the westernmost margin is generally assumed to have been shaped as a STEP-fault (Subduction-Transform Edge Propagator, transcurrent) margin by the westward displacement of the Alboran block, the central Algerian margin is believed to have involved a NW-SE basin opening related to a southward slab rollback. This work sheds insight on this issue, using data acquired in the context of the Algerian-French program SPIRAL (Sismique Profonde et Investigation Régionale en Algérie): a cruise conducted on the 'R/V L'Atalante' in October-November 2009. It has provided 5 new combined onshore-offshore wide-angle seismic profiles and an extensive multi-channel seismic dataset spread along the margin, from Oran to Annaba. In this work, the available structural information on the ~N-S wide-angle transect of Tipaza is presented, where the margin broadens due to the presence of a bathymetric high (the Khayr-Al-Din bank) which is assumed to represent a remaining titled block of the passive margin. Along the transect, 39 OBS and 13 landstations recorded 751 low frequency airgun shots. Travel-time tomography and forward modelling were computed using the software developed by Zelt and Barton (1998) and Zelt and Smith (1992), to obtain the velocity structure in the region. A set of multi-channel seismic reflection profiles including two coincident profiles with the wide-angle data allows a combined interpretation and extend the deep structure in the Bou Ismail Bay. MCS data outline the sedimentary sequence filling the Algerian basin depicting an intensive salt tectonic associated with the Messinan Salinity Crisis and allowing to image locally below the salt layer. The deep penetrating data SPIRAL allow to image the sedimentary sequence in the Algerian basin off Tipaza (West Algiers) and the crustal structure at the continent-ocean boundary. In the Algerian basin off Tipaza, the Moho discontinuity is identified using wide-angle modelling at 11-12 km depth which corresponds in two-way travel-time to 7-8 s. Wide-angle seismic modelling imaged a major thinning of the crust from more of 15 km in the upper margin (KADB) to only 5-6 km in the deep basin. This thinning also marks the rapid transition from a thinned continental crust at the Khayr-al-Din bank to an oceanic crust in the Algerian Basin, revealing a narrow transition zone (20-30 km) between the two domains. This work presents the deep structure of the margin West of Algiers from wide-angle and multichannel seismic data in order to discuss models of opening for the Algerian basin.

Determining the palaeodrainage of the Nile river from a provenance study of the Nile delta cone sediments: an on-going geochemical study

NASA Astrophysics Data System (ADS)

Fielding, Laura; Najman, Yani; Millar, Ian; Butterworth, Peter; Kneller, Ben; Garzanti, Eduardo

2013-04-01

This study documents the palaeodrainage history of the Nile River, in particular the time of transition from a small locally sourced drainage network to the initiation of an extensive Nile catchment, by conducting a provenance study of the well-dated Nile cone sediments. The identification of specific source inputs into the Nile cone has important implications for the prediction of reservoir quality and connectivity in hydrocarbon reservoirs. Presently, the Nile river drains as far south as south of Lake Victoria, with the White Nile draining largely Cratonic basement rocks of Archean to Proterozoic ages and the Blue Nile draining Cenozoic continental flood basalts and Neoproterozoic basement in Ethiopia. However, the timing of catchment expansion to its current extent is highly debated. There are a number of proposed palaeodrainage reconstructions, two of which are: A) The Blue Nile did not connect with the main (lower) Nile until the Late Messinian, and the White Nile did not connect with the lower Nile until at 0.5 Ma (e.g. Issawi and McCauley, 1992). In this model, the pre-Messinian Nile cone sediments are derived exclusively from the northern part of the present drainage basin, from the Red Sea Hills. B) The Blue Nile and Atbara Rivers have been connected to the main (lower) Nile since the Oligocene, simultaneous with large scale regional uplift and volcanism in the Ethiopian Highlands; with the river following a similar course to present day (Burke and Wells 1989). The palaeo-Nile cone sediments have the capacity to provide a unique archive of the river's highly debated palaeodrainage history. Our first objective was to characterise petrographically, geochemically and isotopically each possible source area (Ethiopian Flood Basalts, African Craton and Red Sea Hills) using a multidisciplinary approach in order to identify the presence (if any) of sediment from these sources in the delta core samples. Heavy mineral, petrographic, U-Pb zircon and rutile analyses so far support the hypothesis of the Blue Nile and/or the Red Sea Hills contributing detritus to the Nile delta since the Oligocene with very little input from the White Nile throughout the core. XRF, Sm-Nd and Rb-Sr analyses also point to a significant mafic (Blue Nile or Red Sea Hills) source since the Oligocene. More recent analytical work has involved studying the Lu/Hf of zircon. This is being carried out to assess the occurrence of the 30Ma zircons identified in the core, the Ethiopian Highlands and at Faiyum in the Western Desert. These results are preliminary, and the Red Sea Hills region in particular is subject to on-going work to more completely characterise its geochemical and isotopic signature.

Molecular cloning of NILE glycoprotein and evidence for its continued expression in mature rat CNS.

PubMed

Prince, J T; Alberti, L; Healy, P A; Nauman, S J; Stallcup, W B

1991-11-01

The NILE glycoprotein is a rat neuronal cell adhesion molecule which has been reported to be very similar in structure, function, and distribution to the mouse L1 glycoprotein. Here we report the complete nucleotide sequence of the NILE message (5,208 nucleotides) and the deduced amino acid sequence of the NILE polypeptide (1,257 amino acids). The predicted NILE protein is 96% identical to L1 at the amino acid level, confirming that the two molecules are homologues. The sequence information shows that NILE is a transmembrane molecule with an extensive ectodomain and a much smaller cytoplasmic domain. The extracellular portion of the molecule contains six immunoglobulin C-2 type domains followed by five fibronectin type III repeats. These two structural motifs are characteristic of several other cell adhesion molecules. The cytoplasmic tails of NILE and L1 are identical to each other and distinct from the cytoplasmic regions of all other cell adhesion molecules except Ng-CAM and neuroglian. Several possible sites for phosphorylation are present in the cytoplasmic tail of NILE. Antisera were produced against two NILE-beta-galactosidase fusion proteins containing distinct segments of the NILE polypeptide: the cytoplasmic domain and the segment containing fibronectin type III repeats. Immunoblots with these antisera and Northern blots with a NILE cDNA probe indicate that NILE continues to be expressed in most areas of the mature rat brain. This contradicts previous immunofluorescence data, which suggested that NILE was substantially down-regulated in maturing nerve fiber tracts. This raises the possibility that NILE could be masked in situ by interactions with other cell surface molecules.

Tectonic evolution of the northeastern part of the African continental margin, Egypt

NASA Astrophysics Data System (ADS)

Hussein, I. M.; Abd-Allah, A. M. A.

2001-07-01

The area between Manzalah Lake and the southern Galala Plateau in northeast Egypt constitutes the Galalas, Cairo-Suez, southern Nile Delta and northern Nile Delta structural provinces. The northern Galala Fault separates the Galalas Province from the Cairo-Suez Province and is considered to be the westward extension of the Themed Fault in central Sinai. The pre-Eocene rocks are affected by northeast to east-northeast-orientated folds and reverse faults, as well as east-west-orientated oblique-slip faults with dextral and normal components. Some folds and reverse faults are interpreted to have been formed by northwest to north-northwest-orientated compression related to the Syrian Arc movement, whereas the others by the secondary northwest orientated shortening, which accompanied dextral strike-slip component along the planes of the east-west-orientated faults. The east-west-orientated faults were initially formed during the Late Triassic/Early Jurassic extension related to the drifting of the African/Arabian Plate away from the Eurasian Plate as a result of opening of the Neotethyan Sea. The Neotethyan began to close due to convergence between the two plates, leading to the Syrian Arc deformation. This deformation mildly started in Late Cenomanian and followed by a more intensive phase in Conacian/Santonian. It mildly continued in the Maastrichtian, Early Palæocene and Late Palæocene/Early Eocene. The southward thinning of the pre-Eocene rocks controlled the intensity and style of deformation. Two deformational mechanisms are proposed for the Nile Delta hinge zone. The first is related to Late Oligocene—Early Miocene north-northwest-orientated Alpine compression. The second is related to northward gravitational sliding of the post-Oligocene shale and sandstone over Cretaceous-Eocene carbonates.

Dust Plume off the Coast of Egypt

NASA Technical Reports Server (NTRS)

2007-01-01

Dwarfing the Nile, a river of dust flowed out of the deserts of northern Egypt on May 19, 2007. As the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite passed overhead at 12:05 p.m. local time in Cairo, the sensor captured this image of the dust spreading northward over the Mediterranean Sea from the sandy deserts that span the country. At the margins of the plume, ribbons and ripples of dust are translucent, allowing a glimpse of the desert and water beneath, but in the center, the cloud is opaque, revealing nothing of the surface below. The part of north-central Egypt hidden by the dust plume is the Qattara Depression, the country's lowest point. Dipping down to 133 meters below sea level (436 feet), the depression is home to sandy deserts and dry lake beds that occasionally flood. The sand and fine, lake bed sediments are easily lofted into the air by strong winds that scour the area in late winter and early spring. In the eastern (right-hand) part of the image, the Nile River is lined by narrow ribbons of dull green vegetation. The fan-shaped delta is dotted with tan-colored spots, marking the location of cities and towns. The Nile Valley and Delta make up only a small fraction of the country's total land area, yet they support almost the entire population. The large image provided above has a spatial resolution (level of detail) of 250 meters per pixel. The MODIS Rapid Response Team provides this image in additional resolutions. The Earth Observatory also provides a 250-meter-resolution KMZ file of this image for use with Google Earth.

Multi-scale constraints of sediment source to sink systems in frontier basins: a forward stratigraphic modeling case study of the Levant region

NASA Astrophysics Data System (ADS)

Hawie, Nicolas; Deschamps, Remy; Granjeon, Didier; Nader, Fadi-Henri; Gorini, Christian; Müller, Carla; Montadert, Lucien; Baudin, François

2015-04-01

Recent scientific work underlined the presence of a thick Cenozoic infill in the Levant Basin reaching up to 12 km. Interestingly; restricted sedimentation was observed along the Levant margin in the Cenozoic. Since the Late Eocene successive regional geodynamic events affecting Afro-Arabia and Eurasia (collision and strike slip deformation)induced fast marginal uplifts. The initiation of local and long-lived regional drainage systems in the Oligo-Miocene period (e.g. Lebanon versus Nile) provoked a change in the depositional pattern along the Levant margin and basin. A shift from carbonate dominated environments into clastic rich systems has been observed. Through this communication we explore the importance of multi-scale constraints (i.e.,seismic, well and field data) in the quantification of the subsidence history, sediment transport and deposition of a Middle-Upper Miocene "multi-source" to sink system along the northernLevant frontier region. We prove through a comprehensive forward stratigraphic modeling workflow that the contribution to the infill of the northern Levant Basin (offshore Lebanon) is split in between proximal and more distal clastic sources as well as in situ carbonate/hemipelagic deposition. In a wider perspective this work falls under the umbrella of multi-disciplinary source to sink studies that investigate the impact of geodynamic events on basin/margin architectural evolutions, consequent sedimentary infill and thus on petroleum systems assessment.

Distribution of long-lived radioactive iodine isotope (I-129) in pore waters from the gas hydrate fields on the continental margins: Indication for methane source of gas hydrate deposits

NASA Astrophysics Data System (ADS)

Tomaru, H.; Lu, Z.; Fehn, U.

2011-12-01

Because iodine has a strong association with organic matters in marine environments, pore waters in high methane potential region, in particular gas hydrate occurrences on the continental margins, are enriched significantly in iodine compared with seawater. Natural iodine system is composed of stable and radioactive species, I-129 (half-life of 15.7 Myr) has been used for estimating the age of source formations both for methane and iodine, because iodine can be liberated into pore water during the degradation of organic matter to methane in deep sediments. Here we present I-129 age data in pore waters collected from variety of gas hydrate occurrences on the continental margins. The I-129 ages in pore waters from these locations are significantly older than those of host sediments, indicating long-term transport and accumulation from deep/old sediments. The I-129 ages in the Japan Sea and Okhotsk Sea along the plate boundary between the North American and Amurian Plates correspond to the ages of initial spreading of these marginal seas, pointing to the massive deposition of organic matter for methane generation in deep sediments within limited periods. On the Pacific side of these areas, organic matter-rich back stop is responsible for methane in deep-seated gas hydrate deposits along the Nankai Trough. Deep coaly sequences responsible for deep conventional natural gas deposits are also responsible for overlying gas hydrate deposits off Shimokita Peninsula, NE Japan. Those in the Gulf of Mexico are correlative to the ages of sediments where the top of salt diapirs intrude. Marine sediments on the Pacific Plate subducting beneath the Australian Plate are likely responsible for the methane and iodine in the Hikurangi Trough, New Zealand. These ages reflect well the regional geological settings responsible for generation, transport, and accumulation of methane, I-129 is a key to understand the geological history of gas hydrate deposition.

First images of the crustal structure across the eastern Algerian margin, from deep penetrating seismic data.

NASA Astrophysics Data System (ADS)

Bouyahiaoui, Boualem; Abtout, Abdeslam; Sage, Françoise; Klingelhoeffer, Frauke; Collot, Jean-yves; Yelles-chaouche, Abdelkarim; Marok, Abbas; Djellit, Hamou; Galves, Audrey; Bracène, Rabah; Schnurle, Philippe; Graindorge, David; party, Scientific

2013-04-01

The Algerian continental margin North Africa presents one of only a few examples of a passive continental margin formed in a back-arc environment, which undergoes current compression and is proposed to be reactivated today. In the framework of the Algerian - French SPIRAL research program (Sismique Profonde et Investigation Regionale du nord de l'ALgérie), a seismic cruise was conducted on the R/V Atalante from September to November 2009. During the cruise, deep penetrating low frequency multichannel and wide-angle seismic data were acquired in order to study the deep structure of the Algerian margin. In this work, we present the preliminary results from wide-angle modeling of the North-east Algerian margin in the region of Annaba along a N-S transect using a data set of 42 OBS (ocean bottom seismometers) along a profile extending 117km, and 13 broadband seismological stations along a profile of 80 km length. Travel-time tomography and forward modeling were undertaken to model the velocity structure in this region. The resulting velocity models image the thickness of the sedimentary layers, which varies between a few hundred meters on the continental margin of more than 4 km in the basin. The crust is about 6 km thick in the basin, and thickens to 7-8 km between 40 and 60km distance from the margin toe. Crustal thickness increases to about 22 km at the continental slope over a distance of ~ 90 km. The nature of the crust was determined to be thin oceanic with abnormal velocity gradient in the basin, and thinned continental from around 30 km distance from the coast landward. Integration of the wide-angle seismic data with multichannel seismic, gravity and magnetic data will help to better understand the structure of the Algerian margin and the adjacent oceanic basin in the Annaba region, and to discuss the numerous cinematic models proposed in literature regarding the formation of the north-Algerian basin.

Microbes in deep marine sediments viewed through amplicon sequencing and metagenomics

NASA Astrophysics Data System (ADS)

Biddle, J.; Leon, Z. R.; Russell, J. A., III; Martino, A. J.

2016-12-01

Nearly twenty percent of microbial biomass on Earth can be found in the marine subsurface. The majority of this is concentrated on continental margins, which have been investigated by scientific drilling. On the Costa Rica Margin, Iberian Margin and Peru Margins, sediment samples have been investigated through DNA extraction followed by amplicon and metagenomic sequencing. Overall samples show a high degree of microbial diversity, including many lineages of newly defined groups. In this talk, metagenome assembled genomes of unusual lineages will be presented, including their relationships to shallower relatives. From Costa Rica, in particular, we have retrieved deep relatives of Lokiarchaeota and Thorarchaeota, as well as other deeply branching archaeal relatives. We discuss their genome similarities to both other archaea and eukaryotes. From the Iberian Margin, relatives of Atribacteria and Aerophobetes will be discussed. Finally, we will detail the knowledge lost or gained depending on whether samples are studied via amplicon sequencing or total metagenomics, as studies in other environments have shown that up to 15% of microbial diversity is ignored when samples are studied via amplicon sequencing alone.

OCT structure, COB location and magmatic type of the SE Brazilian & S Angolan margins from integrated quantitative analysis of deep seismic reflection and gravity anomaly data

NASA Astrophysics Data System (ADS)

Cowie, L.; Kusznir, N. J.; Horn, B.

2013-12-01

Knowledge of ocean-continent transition (OCT) structure, continent-ocean boundary (COB) location and magmatic type are of critical importance for understanding rifted continental margin formation processes and in evaluating petroleum systems in deep-water frontier oil and gas exploration. The OCT structure, COB location and magmatic type of the SE Brazilian and S Angolan rifted continental margins are much debated; exhumed and serpentinised mantle have been reported at these margins. Integrated quantitative analysis using deep seismic reflection data and gravity inversion have been used to determine OCT structure, COB location and magmatic type for the SE Brazilian and S Angolan margins. Gravity inversion has been used to determine Moho depth, crustal basement thickness and continental lithosphere thinning. Residual Depth Anomaly (RDA) analysis has been used to investigate OCT bathymetric anomalies with respect to expected oceanic bathymetries and subsidence analysis has been used to determine the distribution of continental lithosphere thinning. These techniques have been validated on the Iberian margin for profiles IAM9 and ISE-01. In addition a joint inversion technique using deep seismic reflection and gravity anomaly data has been applied to the ION-GXT BS1-575 SE Brazil and ION-GXT CS1-2400 S Angola. The joint inversion method solves for coincident seismic and gravity Moho in the time domain and calculates the lateral variations in crustal basement densities and velocities along profile. Gravity inversion, RDA and subsidence analysis along the S Angolan ION-GXT CS1-2400 profile has been used to determine OCT structure and COB location. Analysis suggests that exhumed mantle, corresponding to a magma poor margin, is absent beneath the allochthonous salt. The thickness of earliest oceanic crust, derived from gravity and deep seismic reflection data is approximately 7km. The joint inversion predicts crustal basement densities and seismic velocities which are slightly less than expected for 'normal' oceanic crust. The difference between the sediment corrected RDA and that predicted from gravity inversion crustal thickness variation implies that this margin is experiencing ~300m of anomalous uplift attributed to mantle dynamic uplift. Gravity inversion, RDA and subsidence analysis have also been used to determine OCT structure and COB location along the ION-GXT BS1-575 profile, crossing the Sao Paulo Plateau and Florianopolis Ridge of the SE Brazilian margin. Gravity inversion, RDA and subsidence analysis predict the COB to be located SE of the Florianopolis Ridge. Analysis shows no evidence for exhumed mantle on this margin profile. The joint inversion technique predicts normal oceanic basement seismic velocities and densities and beneath the Sao Paulo Plateau and Florianopolis Ridge predicts crustal basement thicknesses between 10-15km. The Sao Paulo Plateau and Florianopolis Ridge are separated by a thin region of crustal basement beneath the salt interpreted as a regional transtensional structure. Sediment corrected RDAs and gravity derived 'synthetic' RDAs are of a similar magnitude on oceanic crust, implying negligible mantle dynamic topography.

Investigating Continental Margins: An Activity to Help Students Better Understand the Continental Margins of North America

ERIC Educational Resources Information Center

Poli, Maria-Serena; Capodivacca, Marco

2011-01-01

Continental margins are an important part of the ocean floor. They separate the land above sea level from the deep ocean basins below and occupy about 11% of Earth's surface. They are also economically important, as they harbor both mineral resources and some of the most valuable fisheries in the world. In this article students investigate North…

Constraints on the Final Stages of Breakup and Early Spreading history of the Eastern North American Margin from New Multichannel Seismic Data of the Community Seismic Experiment

NASA Astrophysics Data System (ADS)

Becel, A.

2016-12-01

In September-October 2014, the East North American Margin (ENAM) Community Seismic Experiment (CSE) acquired deep penetration multichannel seismic (MCS) reflection on a 500 km wide section of the Mid-Atlantic continental margin offshore North Carolina and Virginia. This margin formed after the Mesozoic breakup of supercontinent Pangea. One of the goals of this experiment is an improved understanding of events surrounding final stage of breakup including the relationship between the timing of rifting and the occurrence of offshore magmatism and early spreading history of this passive margin that remain poorly understood. Deep penetration MCS data were acquired with the 6600 cu.in. tuned airgun array and the 636 channel, 8-km-long streamer of the R/V Marcus Langseth. The source and the streamer were both towed at a depth of 9 m for deep imaging. Here we present initial results from MCS data along two offshore margin normal profiles (450-km long and 370-km-long, respectively), spanning from continental crust 50 km off the coast to mature oceanic crust and a 350-km-long MCS profile along the enigmatic Blake Spur Magnetic Anomaly (BSMA). Initial images reveal a major change in the basement roughness at the BSMA on both margin normal profiles. Landward of this anomaly, the basement is rough and more faulted whereas starting at the anomaly and seaward, the basement is very smooth and reflective. Clear Moho reflections are observed 2.5-3s (7.75-9.3 km assuming an average crustal velocity of 6.2 km/s) beneath the top of the basement on the seaward part of two margin normal profiles and on the margin parallel profile. Intracrustal reflections are also observed over both transitional and oceanic basement. A long-lived mantle thermal anomaly close to the ridge axis during the early opening of the Atlantic Ocean could explain the thicker than normal oceanic crust and smooth basement topography observed in the data.

Deep Margins Under Pressure: Sustaining Biodiversity and Function where Climate Change and Humans Collide

NASA Astrophysics Data System (ADS)

Levin, L. A.

2012-12-01

The ocean's deep continental margins (200 - 3000 m) extend for over 150,000 km and cover 45 million square km. Once considered monotonous and of limited environmental value, we now recognize that they are highly heterogeneous and that the diverse habitats and organisms provide key ecological functions and ecosystem services. Driven by increasing CO2 in the atmosphere, continental slopes are experiencing rapid changes in temperature, oxygen and pH. At the same time they are increasingly exploited for their fisheries, energy and mineral resources. This talk will highlight natural- and climate-change induced hypoxia, acidification and warming on upwelling margins. Natural variations in space and time provide lessons about the evolutionary and ecological responses of animals, communities and ecosystems to individual and multiple stressors. We ask, to what extent do they foretell the future? The overprint of stress from climate change is likely to increase ecosystem vulnerability to human disturbance from oil and gas extraction, fishing and minerals mining, with threats to biodiversity and lowered resilience. These challenges demand a global commitment to improved stewardship of deep-ocean ecosystems and resources. Sustaining the integrity of the deep ocean will require integration of oceanography, biodiversity and conservation science, technology, informatics, economics, policy, law and communication, as well as engagement of stakeholders.

West nile poliomyelitis in a 7-year-old child.

PubMed

Hainline, Margaret L; Kincaid, John C; Carpenter, Denise L; Golomb, Meredith R

2008-11-01

West Nile poliomyelitis is a well-described neurologic manifestation of West Nile viral infection in adults. However, few reports have described this manifestation in children infected with West Nile virus. We describe a 7-year-old boy who developed West Nile poliomyelitis with flaccid paralysis of his left leg. Electrodiagnostic testing and radiologic imaging confirmed anterior horn cell injury. We report on his course clinically and electrodiagnostically over 20 months.

From non-covalent binding to irreversible DNA lesions: nile blue and nile red as photosensitizing agents

PubMed Central

Gattuso, Hugo; Besancenot, Vanessa; Grandemange, Stéphanie; Marazzi, Marco; Monari, Antonio

2016-01-01

We report a molecular modeling study, coupled with spectroscopy experiments, on the behavior of two well known organic dyes, nile blue and nile red, when interacting with B-DNA. In particular, we evidence the presence of two competitive binding modes, for both drugs. However their subsequent photophysical behavior is different and only nile blue is able to induce DNA photosensitization via an electron transfer mechanism. Most notably, even in the case of nile blue, its sensitization capabilities strongly depend on the environment resulting in a single active binding mode: the minor groove. Fluorescence spectroscopy confirms the presence of competitive interaction modes for both sensitizers, while the sensitization via electron transfer, is possible only in the case of nile blue. PMID:27329409

The White Nile as a source for Nile sediments: Assessment using U-Pb geochronology of detrital rutile and monazite

NASA Astrophysics Data System (ADS)

Be'eri-Shlevin, Yaron; Avigad, Dov; Gerdes, Axel

2018-04-01

Basement terranes exposed at the headwaters of the White Nile include Archean-Paleoproterozoic rocks of the Congo Craton, whose northern sectors were severely reworked during Neoproterozoic orogeny. New U-Pb analyses of detrital rutile and monazite from early Quaternary to Recent coastal quartz sands of Israel, at the northeast extension of the Nile sedimentary system, yield mostly late Neoproterozoic ages, with a dominant peak at ca. 600 Ma. While derivation from the reworked sectors of the Craton cannot be negated, the absence of pre-Neoproterozoic rutile and monazite indicates that the detrital contribution from the Congo cratonic nuclei into the main Nile was insignificant. The near absence of White Nile basement-derived heavy minerals from the Nile sands arriving at the Eastern Mediterranean may be explained by a number of factors such as relatively minor erosion of the Cratonic basement nuclei during the Quaternary, late connection of the White Nile to the main Nile system with a possibility that northern segments connected prior to more southerly ones, and a long-term effective sediment blockage mechanism at the mouth of White Nile. Likewise, our previous study demonstrated that Nile sands display a detrital zircon U-Pb-Hf pattern consistent with significant recycling of NE African Paleozoic sediments. It is thus plausible that any detrital contribution from White Nile basement rocks was thoroughly diluted by eroded Paleozoic sediments, or their recycled products, which were likely the greatest sand reservoir in the region. This study adds to previous studies showing the advantage of a multi mineral U-Pb geochronology strategy in constraining sediment provenance patterns.

Crustal architecture of the oblique-slip conjugate margins of George V Land and southeast Australia

USGS Publications Warehouse

Stagg, H.M.J.; Reading, A.M.

2007-01-01

A conceptual, lithospheric-scale cross-section of the conjugate, oblique-slip margins of George V Land, East Antarctica, and southeast Australia (Otway Basin) has been constructed based on the integration of seismic and sample data. This cross-section is characterised by asymmetry in width and thickness, and depth-dependent crustal extension at breakup in the latest Maastrichtian. The broad Antarctic margin (~360 km apparent rift width) developed on thick crust (~42 km) of the Antarctic craton, whereas the narrow Otway margin (~220 km) developed on the thinner crust (~31 km) of the Ross–Delamerian Orogen. The shallow basement (velocities ~5.5 km.s-1) and the deep continental crust (velocities >6.4 km.s-1) appear to be largely absent across the central rift, while the mid-crustal, probably granitic layer (velocities ~6 km.s-1) is preserved. Comparison with published numerical models suggests that the shallow basement and deep crust may have been removed by simple shear, whereas the mid-crust has been ductilely deformed.

Nile River, Lake Nasser, Aswan Dam, Egypt

NASA Image and Video Library

1991-08-11

Egypt's High Aswan Dam on the Nile River at the first cataracts, Nile River, (24.0N, 33.0E) was completed in 1971 to provide cheap hydroelectric power and to regulate the historically uneven flow of the Nile River. The contrast between the largely base rock desert east of the Nile versus the sand covered desert west of the river and the ancient irrigated floodplain downstream from the damsite is clearly shown.

Nile River, Lake Nasser, Aswan Dam, Egypt

NASA Technical Reports Server (NTRS)

1991-01-01

Egypt's High Aswan Dam on the Nile River at the first cataracts, Nile River, (24.0N, 33.0E) was completed in 1971 to provide cheap hydroelectric power and to regulate the historically uneven flow of the Nile River. The contrast between the largely base rock desert east of the Nile versus the sand covered desert west of the river and the ancient irrigated floodplain downstream from the damsite is clearly shown.

Spatial variations in fluvial incision across the eastern margin of Tibet reveal locus of deformation in the deep crust

NASA Astrophysics Data System (ADS)

Kirby, Eric

2017-04-01

The manifestation of coupling among climate, erosion and tectonics along steep topographic margins of orogenic plateaus is strongly dependent on the processes driving crustal thickening. Along the eastern margin of the Tibetan Plateau, a long-standing and vigorous debate persists over whether mountain building occurred largely along upper-crustal faults or was the consequence of distributed thickening in the lower crust. Here I revisit this debate and show how surface deformation recorded by geomorphology over millennial timescales (10^4-105 yr) can yield insight into the role the deep crust along plateau margins. In contrast to the intensively studied Longmen Shan, the topographic margin of the Tibetan Plateau north of the Sichuan Basin follows the north-south Min Shan and cuts orthogonally across the structural grain of the Mesozoic West Qinling orogen. The lack of a direct association of topography with upper crustal faults affords an opportunity to evaluate the patterns of differential rock uplift from geomorphology. First, I employ an empirical calibration of river profile steepness (channel gradient normalized for drainage basin area) and erosion rate from cosmogenic 10Be concentrations in modern sediment. Application to the channels draining the plateau margin reveals a locus of high (300-500 m/Myr) erosion rate coincident with the Min Shan. Second, I present new results of surveying and dating of fluvial terraces developed along the Bailong Jiang, one of the major rivers draining across the plateau margin. A preliminary chronology of terrace formation and abandonment based on radiocarbon and OSL dating of fluvial deposits reveals systematic spatial gradients in fluvial incision, with highest incision rates (1000-2000 m/Myr) localized along the axis of the Min Shan and decreasing toward both the foreland and the plateau. This locus of incision has apparently been sustained through multiple generations of terrace formation and abandonment since at least 80 ka and thus is interpreted to reflect sustained differential rock uplift along this axis. The wavelength of the region of highest incision rates is 80 km and requires either 1) a deeply buried tip of a blind fault, or 2) thickening in the deep crust. We argue that terrace deformation and associated rock uplift likely reflects flow and thickening of deep Tibetan crust against the foreland of the West Qinling.

Spatial variations in fluvial incision across the eastern margin of Tibet reveal locus of thickening in the deep crust

NASA Astrophysics Data System (ADS)

Kirby, Eric; Zhang, Huiping; Chen, Jie

2016-04-01

The manifestation of coupling among climate, erosion and tectonics along steep topographic margins of orogenic plateaus is strongly dependent on the processes driving crustal thickening. Along the eastern margin of the Tibetan Plateau, a long-standing an vigorous debate persists over whether mountain building occurred largely along upper-crustal faults or was the consequence of distributed thickening in the lower crust. Here we revisit this debate and show how surface deformation recorded by geomorphology over millennial timescales (104-105 yr) can yield insight into the role the deep crust along plateau margins. In contrast to the intensively studied Longmen Shan, the topographic margin of the Tibetan Plateau north of the Sichuan Basin follows the north-south Min Shan and cuts orthogonally across the structural grain of the Mesozoic West Qinling orogen. The lack of a direct association of topography with upper crustal faults affords an opportunity to evaluate the patterns of differential rock uplift from geomorphology. First, we employ an empirical calibration of river profile steepness (channel gradient normalized for drainage basin area) and erosion rate from cosmogenic 10Be concentrations in modern sediment. Application to the channels draining the plateau margin reveals a locus of high (300-500 m/Myr) erosion rate coincident with the Min Shan. Second, we present new results of surveying and dating of fluvial terraces developed along the Bailong Jiang, one of the major rivers draining across the plateau margin. A preliminary chronology of terrace tread deposits based on radiocarbon and OSL samples reveals systematic spatial gradients in fluvial incision, with highest incision rates (1000-2000 m/Myr) localized along the axis of the Min Shan and decreasing toward both the foreland and the plateau. This locus of incision has apparently been sustained through multiple generations of terrace formation and abandonment since ca. 80ka and thus is interpreted to reflect sustained differential rock uplift along this axis. The wavelength of the region of highest incision rates is ˜80 km and requires either 1) a deeply buried tip of a blind fault, or 2) thickening in the deep crust. We argue that terrace deformation and associated rock uplift likely reflects flow and thickening of deep Tibetan crust against the foreland of the West Qinling.

Tectonic Inversion Along the Algerian and Ligurian Margins: On the Insight Provided By Latest Seismic Processing Techniques Applied to Recent and Vintage 2D Offshore Multichannel Seismic Data

NASA Astrophysics Data System (ADS)

Schenini, L.; Beslier, M. O.; Sage, F.; Badji, R.; Galibert, P. Y.; Lepretre, A.; Dessa, J. X.; Aidi, C.; Watremez, L.

2014-12-01

Recent studies on the Algerian and the North-Ligurian margins in the Western Mediterranean have evidenced inversion-related superficial structures, such as folds and asymmetric sedimentary perched basins whose geometry hints at deep compressive structures dipping towards the continent. Deep seismic imaging of these margins is difficult due to steep slope and superficial multiples, and, in the Mediterranean context, to the highly diffractive Messinian evaporitic series in the basin. During the Algerian-French SPIRAL survey (2009, R/V Atalante), 2D marine multi-channel seismic (MCS) reflection data were collected along the Algerian Margin using a 4.5 km, 360 channel digital streamer and a 3040 cu. in. air-gun array. An advanced processing workflow has been laid out using Geocluster CGG software, which includes noise attenuation, 2D SRME multiple attenuation, surface consistent deconvolution, Kirchhoff pre-stack time migration. This processing produces satisfactory seismic images of the whole sedimentary cover, and of southward dipping reflectors in the acoustic basement along the central part of the margin offshore Great Kabylia, that are interpreted as inversion-related blind thrusts as part of flat-ramp systems. We applied this successful processing workflow to old 2D marine MCS data acquired on the North-Ligurian Margin (Malis survey, 1995, R/V Le Nadir), using a 2.5 km, 96 channel streamer and a 1140 cu. in. air-gun array. Particular attention was paid to multiple attenuation in adapting our workflow. The resulting reprocessed seismic images, interpreted with a coincident velocity model obtained by wide-angle data tomography, provide (1) enhanced imaging of the sedimentary cover down to the top of the acoustic basement, including the base of the Messinian evaporites and the sub-salt Miocene series, which appear to be tectonized as far as in the mid-basin, and (2) new evidence of deep crustal structures in the margin which the initial processing had failed to reveal.

Biochemical properties of the nerve growth factor-inducible large external (NILE) glycoprotein.

PubMed

Salton, S R; Shelanski, M L; Greene, L A

1983-12-01

In the presence of nerve growth factor (NGF), PC12 pheochromocytoma cells undergo neuronal differentiation with a concomitant 3- to 5-fold increase in the specific level of an Mr = 230,000 cell surface component named the NGF-inducible large external, or NILE, glycoprotein. Antisera raised against NILE glycoprotein (NILE GP) purified from PC12 cells have been found to recognize most, if not all, neurons derived from the peripheral and central nervous systems. In the current studies several of the biochemical properties of NILE GP were investigated. NILE GP was found to be phosphorylated in NGF-treated and -untreated PC12 cells and in cultured rat sympathetic neurons. The phosphate moiety of NILE GP is almost completely alkali labile, suggesting that phosphoserine groups predominate. Immunoprecipitation experiments revealed that incorporation of [32P]phosphate into NILE GP relative to total PC12 cell phosphoprotein was not significantly altered at 12 and 24 hr of NGF treatment but was enhanced 3-fold after 7 days and up to 5-fold after 2 to 3 weeks of NGF exposure. These changes in phosphorylated NILE GP paralleled, and therefore appeared to be mainly a consequence of, the NGF-induced increase in total cellular levels of NILE GP. By two-dimensional gel analysis, anti-NILE GP selectively immunoprecipitated two NGF-inducible spots (apparent Mr = 230,000; pI = 6.4 to 6.6) from PC12 cells labeled with either [3H] fucose, [35S]methionine, or [32P]phosphate. Anti-NILE GP immunoprecipitated a single band (apparent Mr = 205,000) from extracts of rat brain labeled with [3H] glucosamine. This confirms the previously established apparent molecular weight difference between central and peripheral NILE GP cross-reactive material. When PC12 cells, cerebellar cultures, and cultured cerebral cortex were treated with tunicamycin and labeled with [35S]methionine, nonglycosylated bands each with Mr = 160,000 were immunoprecipitated, implying that the differences in the mobilities on sodium dodecyl sulfate gels of cross-reactive NILE GP from different tissues is due to variation in glycosylation rather than to large differences in apoprotein structure. Prolonged treatment of PC12 cells with trypsin produced an immunoreactive fragment of NILE GP of apparent Mr = 28,000 that was phosphorylated but not glycosylated, and that remained in the membrane. NILE GP remained predominantly membrane associated under a variety of aqueous extraction conditions, suggesting that it is an integral membrane protein.

Switchgrass cultivars alter microbial contribution to deep soil C

USDA-ARS?s Scientific Manuscript database

Switchgrass (Panicum virgatum L.) is a perennial, cellulosic biofuel feedstock capable of growing under a wide variety of climatic conditions on land marginally suited to cultivated crops. Due to its perennial nature and deep rooting characteristics, switchgrass contributes to soil C sequestration ...

Heat flow anomalies on the Western Mediterranean margins: first results from the WestMedFlux-2016 cruise

NASA Astrophysics Data System (ADS)

Poort, Jeffrey; Lucazeau, Francis; Le Gal, Virginie; Rabineau, Marina; Dal Cin, Michela; Bouzid, Abderrezak; Palomino, Desirée; Leroux, Estelle; Akhmanov, Grigory; Battani, Anne; Bachir, Roza Si; Khlystov, Oleg; Koptev, Aleksandre

2017-04-01

While there is now a large consensus that Western Mediterranean basins developed in a Miocene back-arc setting due to slab roll-back and that some of its domains are floored by oceanic crust, there is still a lot of speculation on the configuration, nature and evolution of its margins and the ocean-continent transitions (OCT). A thick Messinian layer of evaporites in the deep basin obscures deep seismic reflectors, and only recently seismic refraction and wide-angle studies revealed a confident picture of basement configuration. In order to further constrain models of crustal structure and margin evolution, heat flow is one of the key parameters needed. Recent heat flow studies on other margins have shown the existence of a persistent thermal anomaly under rifted margins that urges to reconsider the classical models of its evolution. The young age of OCT and ceased oceanic formation in the Western Mediterranean make it an interesting test case for a thermo-mechanical study of its margins. The presence of halokinetic structuring and salt diapirs urges the need of close spaced heat flow measurement to evaluate heat refraction and advective heat transfer by fluid migration. During the WestMedFlux cruise on the research vessel L'Atalante, we collected a total of 150 new heat flow measurement (123 in pogo mode, 27 with a sediment corer) in the deep basin of the Western Mediterranean where heat flow data were sparse. Preliminary analysis of the heat flow data confirms two regional trends: in the southern Provencal basin an overall increase from west to east (from about 60 mW/m2 at the Golf of Lion towards 75 mW/m2 at the West-Sardinia margin), while in the northern part of the Algero-Balearic basin heat flow increases from east to west (from about 80 to 100 mW/m2). On this regional trends, several local anomalies are clearly differentiated. In the deep oceanic basin, strong anomalies seem to be merely associated to salt diapiric structures. On the OCT and on the rifted continent, both strongly reduced and elevated heat flow are observed and suggest other heat sink and sources. We will discuss on the different processes that might have affected the surface heat flow (e.g., bottom water currents, slope instabilities and focused fluid migrations) and try to link the large scale heat flow patterns with crustal nature, structuring of the margins and mantle dynamics.

Source and migration of dissolved manganese in the Central Nile Delta Aquifer, Egypt

NASA Astrophysics Data System (ADS)

Bennett, P. C.; El Shishtawy, A. M.; Sharp, J. M.; Atwia, M. G.

2014-08-01

Dissolved metals in waters in shallow deltaic sediments are one of the world's major health problems, and a prime example is arsenic contamination in Bangladesh. The Central Nile Delta Aquifer, a drinking water source for more than 6 million people, can have high concentrations of dissolved manganese (Mn). Standard hydrochemical analyses coupled with sequential chemical extraction is used to identify the source of the Mn and to identify the probable cause of the contamination. Fifty-nine municipal supply wells were sampled and the results compared with published data for groundwaters and surface waters. Drill cuttings from 4 wells were collected and analyzed by sequential chemical extraction to test the hypothesized Mn-generating processes. The data from this research show that the Mn source is not deep saline water, microbial reduction of Mn oxides at the production depth, or leakage from irrigation drainage ditches. Instead, Mn associated with carbonate minerals in the surficial confining layer and transported down along the disturbed well annulus of the municipal supply wells is the likely source. This analysis provides a basis for future hydrogeological and contaminant transport modeling as well as remediation-modification of well completion practices and pumping schedules to mitigate the problem.

MARGATS cruise: investigation of the deep internal structure and the heterogeneous margins of the Demerara plateau reveals a polyphased volcanic history

NASA Astrophysics Data System (ADS)

Graindorge, D.; Museur, T.; Roest, W. R.; Klingelhoefer, F.; Loncke, L.; Basile, C.; Poetisi, E.; Deverchere, J.; Heuret, A.; Jean-Frederic, L.; Perrot, J.

2017-12-01

The MARGATS scientific cruise was carried out from October 20th to November 16th 2016 on board the R/V L'Atalante, offshore Suriname and French Guiana. This cruise is part of a program dedicated to the geological investigation of the continental margin, including the Demerara plateau, following the GUYAPLAC (2003), IGUANES (2013) and DRADEM (2016) cruises. The aim of MARGATS was to image the internal structure of the Demerara plateau and its different margins using coincident deep penetrating wide angle refraction and multi channel reflection seismic (MCS) methods. During the MARGATS experiment 171 OBS deployments were distributed along 4 wide-angle lines. Along each wide-angle line we also recorded coincident MCS data using a 3 km long 480 channel streamer. The dataset was completed by three MCS lines along the eastern part of the Demerara plateau. MCS MAR007 line which is coincident with line OBS MAR-3 was extended on land by 13 land stations deployed along the Maroni River. This line, together with MCS MAR001 and the coincident OBS MAR-1 line reveal the highly homogeneous deep structure of the internal part of the plateau. MCS MAR005 line, which is coincident with OBS MAR-2, MCS MAR006 line coincident with OBS MAR-4, MCS MAR002, MCS MAR003 and MCS MAR004 helps to elucidate the structural complexity of the northern transform margin and the eastern divergent margin of the plateau. These new datasets are highly complementary to the DRADEM dredge results which provide evidence for mid Jurassic volcanic rocks along the plateau and significant vertical displacements along the transform margin. These results allow to interpret the plateau as the remains of a huge jurassic volcanic divergent margin along the Central Atlantic ocean to the west, possibly remobilized during the cretaceous opening of the Equatorial Atlantic ocean as an highly oblique margin to the north and a divergent margin to the east in persistent presence of volcanism. This AGU session will be a great opportunity to present the exceptional quality of the seismic data, after the initial processing steps and how these data are conditioning a new understanding of the Demarara plateau and its margins which implies the hypothetic role of a new hot spot shaping the complex polyphased history of the structure.

The deep Algerian margin structure revisited by the Algerian-French SPIRAL research program, stage 2 : Wide-ange seismic experiment

NASA Astrophysics Data System (ADS)

Klingelhoefer, Frauke; Yellès, Abdelkarim; Bracène, Rabah; Graindorge, David; Ouabadi, Aziouz; Schnürle, Philippe; Scientific Party, Spiral

2010-05-01

During the second leg of the Algerien - French SPIRAL (Sismique Profonde et Investigation Regionale du Nord de l'ALgerie) cruise conducted on the R/V Atalante in October and November 2009 an extensive wide-angle seismic data-set was acquired on 5 regional transects off Algeria, from Arzew bay to the west, to Annaba to the east. The profiles are between 80 and 180 km in length and around 40 ocean-bottom seismometers were deployed on each profile. A 8350 cu. inch tuned airgun array consisting of 10 Bolt airguns was used to generate of deep frequency to allow for a good penetration. All profiles were extended on land up to 150 km by land-stations to better constrain the structure of the margin and the nature of the ocean-continent transition zone. Coincident reflection seismic, gravity and magnetic data were acquired on all profiles during the first leg of the cruise. The resulting data quality is very good with deep penetrating arrivals on most of the instruments. Only on very few instruments a deep salt layer inhibits deeper penetration of the seismic energy. Two instruments were lost and all other yielded useful information on geophone and hydrophone channels. Instruments located close to the coast show arrivals from thick sedimentary layers. Instruments located on oceanic crust indicate a relatively thin crust overlying a mantle layer characterised by seismic velocities of 8 km/s. Forward and inverse modelling of the wide-angle seismic data will help constrain the deep structure of the margin, the nature of the crust and might help to constrain possible existence of a detached slab in the upper mantle. Integration of the wide-angle seismic data with multichannel seismic, gravity and magnetic data will enable us to better understand the tectonic history and the structure of the Algerian margin.

Diversity of the benthic macrofauna off northern Namibia from the shelf to the deep sea

NASA Astrophysics Data System (ADS)

Eisenbarth, Simone; Zettler, Michael L.

2016-03-01

In late summer 2011, shortly after an upwelling event, 17 stations ranging from 30 to 2513 m water depth have been sampled at 20° south in the northern part of the Benguela Current Large Marine Ecosystem (BCLME) for the investigation of the benthic macrofauna. Sediments of this area are dominated by silt. At the time of sampling, oxygen conditions on the shelf were poor (between 0.42 and 0.68 ml l- 1) but not hypoxic. Below 400 m, however, concentrations rose steadily up to 5.28 ml l- 1. Macrozoobenthic communities along this depth gradient are described, revealing among others the community structure for the continental margin area and the deep sea off northern Namibia for the first time. Cluster analysis revealed 5 different communities along the depth gradient with three shelf communities, one continental margin community and one deep-sea community. All in all, 314 different taxa were found with polychaetes being the most abundant group. Diversity index (Shannon) was lowest for the shallow water community with 2.21 and highest for the deep-sea community with 4.79, showing a clear trend with increasing water depth. Species richness, however, reached its maximum with 187 taxa along the continental margin between 400 and 1300 m water depth. Dominant species for each community are named with the two Cumacea, Iphinoeafricana and Upselaspis caparti, being characteristic for the shallow water community. On the shelf, we found surprisingly high biomass values (23-123 g m- 2), mainly caused by polychaetes, the bivalve Sinupharus galatheae and the gastropod Nassarius vinctus. In terms of composition, the remaining communities were dominated by polychaetes with members of the Paraonidae dominating along the continental margin where we also found surprisingly high abundances of the bivalves Pecten sp. and Dosinia sp. Spionid polychaetes and some representatives of the genus Paraonis were the most common organisms for the deep-sea community.

The Influence of Topography on Subaqueous Sediment Gravity Flows and the Resultant Deposits: Examples from Deep-water Systems in Offshore Morocco and Offshore Trinidad

NASA Astrophysics Data System (ADS)

Deng, H.; Wood, L.; Overeem, I.; Hutton, E.

2016-12-01

Submarine topography has a fundamental control on the movement of sediment gravity flows as well as the distribution, morphology, and internal heterogeneity of resultant overlying, healing-phase, deep-water reservoirs. Some of the most complex deep-water topography is generated through both destructive and constructive mass transport processes. A series of numerical models using Sedflux software have been constructed over high resolution mass transport complexes (MTCs) top paleobathymetric surfaces mapped from 3D seismic data in offshore Morocco and offshore eastern Trinidad. Morocco's margin is characterized by large, extant rafted blocks and a flow perpendicular fabric. Trinidad's margin is characterized by muddier, plastic flows and isolated extrusive diapiric buttresses. In addition, Morocco's margin is a dry, northern latitude margin that lacks major river inputs, while Trinidad's margin is an equatorial, wet climate that is fed by the Orinoco River and delta. These models quantitatively delineate the interaction of healing-phase gravity flows on the tops of two very different topographies and provide insights into healing-phase reservoir distribution and stratigraphic trap development. Slopes roughness, curvatures, and surface shapes are measured and quantified relative to input points to quantify depositional surface character. A variety of sediment gravity flow types have been input and the resultant interval assessed for thickness and distribution relative to key topography parameters. Mathematical relationships are to be analyzed and compared with seismic data interpretation of healing-phase interval character, toward an improved model of gravity sedimentation and topography interactions.

Simulation of the last sapropel event using high-regional oceanic model

NASA Astrophysics Data System (ADS)

Vadsaria, Tristan; Ramstein, Gilles; Li, Laurent; Dutay, jean-Claude

2017-04-01

Since decades, the simulation of sapropel events remains a challenge. These events, occurring periodically in the Mediterranean Sea produce a strong stratification of the water column and break intermediate and deep convection, thereby leading to a decrease in deep water oxygen, of which evidence are recorded in marine sediment cores. Data from Mediterranean sediments have thus helped to better understand the anoxia process, in particular for the last sapropel event, S1, lasting 3000 years about 10 kyrs ago. However the causal link between insolation changes and the African monsoon variations - thought to be the trigger of sapropel events -, and anoxia has still to be quantified. From a modelling point of view, a requisite for studying sapropel events is to capture seasonal winds that are instrumental in producing convection in the Med Sea. Recently, the development of high-resolution several models studies intend to fill this gap, building different scenarios (Grimm et al, 2015). Combining an atmospheric GCM (LMDZ4) and a high-resolution oceanic model (NEMOMED8, resolution of 1/8 degree) dedicated to the Med Sea, our first objective is to test whether monsoon precipitation triggered by insolation changes can increase the Nile run-off enough to stratify the East Mediterranean Sea. We notably show that a 15 mSv Nile runoff increase triggers a large decrease of convection in the whole Eastern Mediterranean Sea associated with strong anoxia in bottom waters.. Comparisons of our first experiments with δ18O and ɛ-Nd data will also be presented. Future work includes extending our simulations to investigate whether sapropel events can be maintained on longer time scales.

21 CFR 866.3940 - West Nile virus serological reagents.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human serum...

21 CFR 866.3940 - West Nile virus serological reagents.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human serum...

21 CFR 866.3940 - West Nile virus serological reagents.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human serum...

21 CFR 866.3940 - West Nile virus serological reagents.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human serum...

21 CFR 866.3940 - West Nile virus serological reagents.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human serum...

Major and trace element distribution in soil and sediments from the Egyptian central Nile Valley

NASA Astrophysics Data System (ADS)

Badawy, W. M.; Ghanim, E. H.; Duliu, O. G.; El Samman, H.; Frontasyeva, M. V.

2017-07-01

The distributions of 32 major and trace elements in 72 surface soil and sediment samples collected from the Asyut to Cairo Nile river section were determined by epithermal neutron activation analysis and compared with corresponding data for the Upper Continental Crust, North American Shale Composite, Average Soil and Average Sediment as well as suspended sediments from Congo and Upper Niger Rivers, in order to establish to which extent the Nile sedimentary material can be related to similar material all over the world as well as to local geology. Their relative distributions indicate the presence of detrital material of igneous origin, most probably resulting from weathering of the Ethiopian Highlands and transported by the Blue Nile, the Nile main tributary. The distributions of nickel, zinc, and arsenic contents suggest that the lower part of the Nile and its surroundings including the Nile Delta is not seriously polluted with heavy metals, so that, in spite of a human activity, which lasted four millennia, the Nile River continues to be less affected by any anthropogenic contamination.

Nile Delta vegetation response to Holocene climate variability

USGS Publications Warehouse

Bernhardt, Christopher E.; Horton, Benjamin P.; Stanley, Jean-Daniel

2012-01-01

A 7000 yr palynologic record from Burullus Lagoon, Nile Delta, Egypt, is assessed to investigate changes in terrestrial vegetation in response to Nile flow. Previous studies in this region have shown that sea-level rise in the early to mid-Holocene, and markedly increased human land use during the past several centuries, altered vegetation in and around the lagoon. The pollen record from this study documents changes in delta vegetation that likely reflect variations in Nile flow. We suggest that Cyperaceae pollen is a sensitive marker of precipitation over the Nile headwaters and the resultant Nile flow. Decreases in Cyperaceae pollen, interpreted as a marker for diminished Nile flow, as well as the increase in relative abundance of microscopic charcoal, occurred at ca. 6000–5500, ca. 5000, ca. 4200, and ca. 3000 cal. yr B.P. (calibrated years before present). These correspond to extreme regional and global aridity events associated with a more southerly mean position of the Intertropical Convergence Zone. These changes, also recorded by other proxy studies, indicate that several marked regional drought events affected the Nile Delta region and impacted ancient Egyptian and Middle Eastern civilizations.

Deep Stucture of the Northwestern Atlantic Moroccan Margin Studied by OBS and Deep Multichannel Seismic Reflection.

NASA Astrophysics Data System (ADS)

MALOD, J. A.; Réhault, J.; Sahabi, M.; Géli, L.; Matias, L.; Diaz, J.; Zitellini, N.

2001-12-01

The Northwestern Atlantic Moroccan margin, a conjugate of the New Scotland margin, is one of the oldest passive margin of the world. Continental break up occurred at early Liassic time and the deep margin is characterized by a large salt basin. A good knowledge of this basin is of major interest to improve the initial reconstruction between Africa, North America and Iberia (Eurasia). It is also a good opportunity to study a mature passive margin and model its structure and evolution.Moreover, there is a need to assess the geological hazards linked to the neotectonic activity within the Africa-Eurasia plate boundary. These topics have been adressed during the SISMAR cruise carried out from April 9th to May 4th 2001.During this cruise, 3667 km of multichannel seismic reflection (360 channels, 4500 m long streamer, 4800 ci array of air guns) were recorded together with refraction records by means of 48 OBH/OBS drops. Simultaneously, some of the marine profiles have been extended onshore with 16 portable seismic land stations. We present the initial results of this study. Off El Jadida, the Moho and structures within the thinned continental crust are well imaged on both the reflection and refraction records. In the northern area, off Casablanca, we follow the deepening of the moroccan margin beneath the up to 9 sec (twtt) allochtonous series forming a prism at the front the Rif-Betic chain. Sismar cruise has been also the opportunity to record long seismic profiles making the junction between the Portuguese margin and the Moroccan one, and crossing the Iberian-African plate boundary. This allows to observe the continuity of the sedimentary sequence after the end of the large inter-plate motion in Early Cretaceous. In addition to the authors, SISMAR Group includes: AMRHAR Mostafa, BERMUDEZ VASQUEZ Antoni, CAMURRI Francesca, CONTRUCCI Isabelle, CORELA Carlos, DIAZ Jordi, DORVAL Philippe, EL ARCHI Abdelkrim, EL ATTARI Ahmed, GONZALEZ Raquel, HARMEGNIES Francois, JAFFAL Mohamed, KLINGELÖFER Fraucke, LANDURÉ Jean Yves, LEGALL Bernard, MAILLARD-LENOIR Agnès, MARTIN Christophe, MEHDI Khalid, MERCIER Eric, MOULIN Maryline, OUAJHAIN Brahim, PERROT Julie, ROLET Joël, RUELLAN Etienne, TEIXIRA Fernando, TERRINHA Pedro, ZOURARAH Bendehhou.

An-integrated seismic approach to de-risk hydrocarbon accumulation for Pliocene deep marine slope channels, offshore West Nile Delta, Egypt

NASA Astrophysics Data System (ADS)

Othman, Adel A. A.; Bakr, Ali; Maher, Ali

2017-12-01

The Nile Delta basin is a hydrocarbon rich province that has hydrocarbon accumulations generated from biogenic and thermogenic source rocks and trapped in a clastic channel reservoirs ranging in age from Pliocene to Early Cretaceous. Currently, the offshore Nile Delta is the most active exploration and development province in Egypt. The main challenge of the studied area is that we have only one well in a channel system exceeds fifteen km length, where seismic reservoir characterization is used to de-risk development scenarios for the field by discriminating between gas sand, water sand and shale. Extracting the gas-charged geobody from the seismic data is magnificent input for 3D reservoir static modelling. Seismic data, being non-stationary in nature, have varying frequency content in time. Spectral decomposition analysis unravels the seismic signal into its initial constituent frequencies. Frequency decomposition of a seismic signal aims to characterize the time-dependent frequency response of subsurface rocks and reservoirs for imaging and mapping of bed thickness, geologic discontinuities and channel connectivity. Inversion feasibility study using crossplot between P-wave impedance (Ip) and S-wave impedance (Is) which derived from well logs (P-wave velocity, S-wave velocity and density) is applied to investigate which inversion type would be sufficient enough to discriminate between gas sand, water sand and shale. Integration between spectral analysis, inversion results and Ip vs. Is crossplot cutoffs help to generate 3D lithofacies cubes, which used to extract gas sand and water sand geobodies, which is extremely wonderful for constructing facies depositional static model in area with unknown facies distribution and sand connectivity. Therefore de-risking hydrocarbon accumulation and GIIP estimation for the field became more confident for drilling new development wells.

Transmission of West Nile virus from an organ donor to four transplant recipients.

PubMed

Iwamoto, Martha; Jernigan, Daniel B; Guasch, Antonio; Trepka, Mary Jo; Blackmore, Carina G; Hellinger, Walter C; Pham, Si M; Zaki, Sherif; Lanciotti, Robert S; Lance-Parker, Susan E; DiazGranados, Carlos A; Winquist, Andrea G; Perlino, Carl A; Wiersma, Steven; Hillyer, Krista L; Goodman, Jesse L; Marfin, Anthony A; Chamberland, Mary E; Petersen, Lyle R

2003-05-29

In August 2002, fever and mental-status changes developed in recipients of organs from a common donor. Transmission of West Nile virus through organ transplantation was suspected. We reviewed medical records, conducted interviews, and collected blood and tissue samples for testing with a variety of assays. Persons who donated blood to the organ donor and associated blood components were identified and tested for West Nile virus. We identified West Nile virus infection in the organ donor and in all four organ recipients. Encephalitis developed in three of the organ recipients, and febrile illness developed in one. Three recipients became seropositive for West Nile virus IgM antibody; the fourth recipient had brain tissue that was positive for West Nile virus by isolation and nucleic acid and antigen assays. Serum specimens obtained from the organ donor before and immediately after blood transfusions showed no evidence of West Nile virus; however, serum and plasma samples obtained at the time of organ recovery were positive on viral nucleic acid testing and viral culture. The organ donor had received blood transfusions from 63 donors. A review of blood donors and follow-up testing identified one donor who had viremia at the time of donation and who became seropositive for West Nile virus IgM antibodies during the next two months. Our investigation of this cluster documents the transmission of West Nile virus by organ transplantation. Organ recipients receiving immunosuppressive drugs may be at high risk for severe disease after West Nile virus infection. Blood transfusion was the probable source of the West Nile virus viremia in the organ donor. Copyright 2003 Massachusetts Medical Society

Neuropsychological Impact of West Nile Virus Infection: An Extensive Neuropsychiatric Assessment of 49 Cases in Canada.

PubMed

Samaan, Zainab; McDermid Vaz, Stephanie; Bawor, Monica; Potter, Tammy Hlywka; Eskandarian, Sasha; Loeb, Mark

2016-01-01

West Nile virus emerged as an important human pathogen in North America and continues to pose a risk to public health. It can cause a highly variable range of clinical manifestations ranging from asymptomatic to severe illness. Neuroinvasive disease due to West Nile virus can lead to long-term neurological deficits and psychological impairment. However, these deficits have not been well described. The objective of this study was to characterize the neuropsychological manifestations of West Nile virus infection with a focus on neuroinvasive status and time since infection. Patients from Ontario Canada with a diagnosis of neuroinvasive disease (meningitis, encephalitis, or acute flaccid paralysis) and non-neuroinvasive disease who had participated in a cohort study were enrolled. Clinical and laboratory were collected, as well as demographics and medical history. Cognitive functioning was assessed using a comprehensive battery of neuropsychological tests. Data from 49 individuals (32 with West Nile fever and 17 with West Nile neuroinvasive disease) were included in the present cross-sectional analysis. Patterns of neuropsychological impairment were comparable across participants with both neuroinvasive and non-neuroinvasive West Nile virus infection on all cognitive measures. Neuropsychiatric impairment was also observed more frequently at two to four years post-infection compared to earlier stages of illness. Our data provide objective evidence for cognitive difficulties among patients who were infected with West Nile virus; these deficits appear to manifest regardless of severity of West Nile virus infection (West Nile fever vs. West Nile neuroinvasive disease), and are more prevalent with increasing illness duration (2-4 years vs. 1 month). Data from this study will help inform patients and healthcare providers about the expected course of recovery, as well as the need to implement effective treatment strategies that include neuropsychological interventions.

Deep Segmentation from 2D Forward Modeling and 3D Tomography of the Maranhão-Barreirinhas-Ceará Margin, NW Brazil

NASA Astrophysics Data System (ADS)

Afonso Dias, Nuno; Afilhado, Alexandra; Schnürle, Philippe; Gallais, Flora; Soares, José; Fuck, Reinhardt; Cupertino, José; Viana, Adriano; Moulin, Maryline; Aslanian, Daniel; Matias, Luís; Evain, Mikael; Loureiro, Afonso

2017-04-01

The deep crustal structure of the North-East equatorial Brazilian margin, was investigated during the MAGIC (Margins of brAzil, Ghana and Ivory Coast) joint project, conducted in 2012. The main goal set to understand the fundamental processes leading to the thinning and finally breakup of the continental crust, in a context of a Pull-apart system with two strike-slip borders. The offshore Barreirinhas Basin, was probed by a set of 5 intersecting deep seismic wide-angle profiles, with the deployment of short-period OBS's from IFREMER and land stations from the Brazilian pool. The experiment was devoted to obtain the 2D structure along the directions of flow lines, parallel to margin segmentation and margin segmentation, from tomography and forward modeling. The OBS's deployed recorded also lateral shooting along some profiles, allowing a 3D tomography inversion complementing the results of 2D modeling. Due to the large variation of the water column thickness, heterogeneous crustal structure and Moho depth, several approaches were tested to generate initial input models, to set the grid parameterization and inversion parameters. The assessment of the 3D model was performed by standard synthetic tests and comparison with the obtained 2D forward models. The results evidence a NW-SE segmentation of the margin, following the opening direction of this pull-apart basin, and N-S segmentation that marks the passage between Basins II-III. The signature of the segmentation is evident in the tomograms, where the shallowing of the basement from Basin II towards the oceanic domain is well marked by a NW-SE velocity gradient. Both 2D forward modeling and 3D tomographic inversion indicate a N-S segmentation in the proto-oceanic and oceanic domains, at least at the shallow mantle level. In the southern area the mantle is much faster than on the north. In all profiles crossing Basin II, a deep layer with velocities of 7-4-7.6 km/s generates both refracted as well as reflected phases from its boundaries, in agreement with the 3D model, which indicate a much more gradual transition of crustal velocities to mantle-velocities, than in the remaining segments. The intersection of Basins II, III and proto-oceanic crust is well marked by the absence of seismic energy propagation at deep crust to mantle levels, with no lateral arrival being recorded. Publication supported by FCT- project UID/GEO/50019/2013 - Instituto Dom Luiz.

The initiation and evolution of the River Nile

NASA Astrophysics Data System (ADS)

Fielding, Laura; Najman, Yani; Millar, Ian; Butterworth, Peter; Garzanti, Eduardo; Vezzoli, Giovanni; Barfod, Dan; Kneller, Ben

2018-05-01

The Nile is generally regarded as the longest river in the world. Knowledge of the timing of the Nile's initiation as a major river is important to a number of research questions. For example, the timing of the river's establishment as a catchment of continental proportions can be used to document surface uplift of its Ethiopian upland drainage, with implications for constraining rift tectonics. Furthermore, the time of major freshwater input to the Mediterranean is considered to be an important factor in the development of sapropels. Yet the river's initiation as a major drainage is currently constrained no more precisely than Eocene to Pleistocene. Within the modern Nile catchment, voluminous Cenozoic Continental Flood Basalts (CFBs) are unique to the Ethiopian Highlands; thus first detection of their presence in the Nile delta record indicates establishment of the river's drainage at continental proportions at that time. We present the first detailed multiproxy provenance study of Oligocene-Recent Nile delta cone sediments. We demonstrate the presence of Ethiopian CFB detritus in the Nile delta from the start of our studied record (c. 31 Ma) by (1) documenting the presence of zircons with U-Pb ages unique, within the Nile catchment, to the Ethiopian CFBs and (2) using Sr-Nd data to construct a mixing model which indicates a contribution from the CFBs. We thereby show that the Nile river was established as a river of continental proportions by Oligocene times. We use petrography and heavy mineral data to show that previous petrographic provenance studies which proposed a Pleistocene age for first arrival of Ethiopian CFBs in the Nile delta did not take into account the strong diagenetic influence on the samples. We use a range of techniques to show that sediments were derived from Phanerozoic sedimentary rocks that blanket North Africa, Arabian-Nubian Shield basement terranes, and Ethiopian CFB's. We see no significant input from Archaean cratons supplied directly via the White Nile in any of our samples. Whilst there are subtle differences between our Nile delta samples from the Oligocene and Pliocene compared to those from the Miocene and Pleistocene, the overall stability of our signal throughout the delta record, and its similarity to the modern Nile signature, indicates no major change in the Nile's drainage from Oligocene to present day.

Resuspension and Shelf-Deep Ocean Exchange in the Northern California Current: New Insights From Underwater Gliders

NASA Astrophysics Data System (ADS)

Erofeev, A.; Barth, J. A.; Shearman, R. K.; Pierce, S. D.

2016-02-01

Shelf-deep ocean exchange is dominated by wind-driven upwelling and downwelling in the northern California Current. The interaction of strong, along-shelf jets with coastline and bottom topographic features can also create significant cross-margin exchange. We are using data from over 60,000 kilometers of autonomous underwater glider tracks to understand the temporal and spatial distribution of shelf-deep ocean exchange off central Oregon. Year-round glider observations of temperature, salinity, depth-averaged currents, chlorophyll fluorescence, light backscatter, and colored dissolved organic matter fluorescence from a single cross-margin transect are used to examine shelf-deep ocean exchange mechanisms. During summer, cross-margin exchange is dominated by wind-driven upwelling and the relaxation or reversal of the dominant southward winds. This process has been fairly well observed and studied due to the relatively low sea states and winds during summer. There is far less data from fall and winter off Oregon, a time of strong winds and large waves. We use autonomous underwater gliders to sample during the winter, including through the fall and spring transitions. Glider observations of suspended material detected via light backscatter, show time-space variations in resuspension in the bottom boundary layer due to winds, waves and currents. Examples of shelf-deep ocean exchange are shown by layers with high light backscatter separating from the bottom near the shelf break and extending into the interior along isopycnals. We describe these features and events in relationship to wind-forcing, along-shelf flows, and other forcing mechanisms.

Impact of Margin Status on Local Recurrence After Mastectomy for Ductal Carcinoma In Situ

DOE Office of Scientific and Technical Information (OSTI.GOV)

Childs, Stephanie K.; Chen, Yu-Hui; Duggan, Margaret M.

Purpose: To examine the rate of local recurrence according to the margin status for patients with pure ductal carcinoma in situ (DCIS) treated by mastectomy. Methods and Materials: One hundred forty-five consecutive women who underwent mastectomy with or without radiation therapy for DCIS from 1998 to 2005 were included in this retrospective analysis. Only patients with pure DCIS were eligible; patients with microinvasion were excluded. The primary endpoint was local recurrence, defined as recurrence on the chest wall; regional and distant recurrences were secondary endpoints. Outcomes were analyzed according to margin status (positive, close (≤2 mm), or negative), location ofmore » the closest margin (superficial, deep, or both), nuclear grade, necrosis, receptor status, type of mastectomy, and receipt of hormonal therapy. Results: The primary cohort consisted of 142 patients who did not receive postmastectomy radiation therapy (PMRT). For those patients, the median follow-up time was 7.6 years (range, 0.6-13.0 years). Twenty-one patients (15%) had a positive margin, and 23 patients (16%) had a close (≤2 mm) margin. The deep margin was close in 14 patients and positive in 6 patients. The superficial margin was close in 13 patients and positive in 19 patients. One patient experienced an isolated invasive chest wall recurrence, and 1 patient had simultaneous chest wall, regional nodal, and distant metastases. The crude rates of chest wall recurrence were 2/142 (1.4%) for all patients, 1/21 (4.8%) for those with positive margins, 1/23 (4.3%) for those with close margins, and 0/98 for patients with negative margins. PMRT was given as part of the initial treatment to 3 patients, 1 of whom had an isolated chest wall recurrence. Conclusions: Mastectomy for pure DCIS resulted in a low rate of local or distant recurrences. Even with positive or close mastectomy margins, the rates of chest wall recurrences were so low that PMRT is likely not warranted.« less

Deep structure of the Algerian continental margin in the region of the Great Kabylies - Insights from wide-angle seismic data modelling

NASA Astrophysics Data System (ADS)

Aidi, Chafik; Klingelhoefer, F.; Yelles-Chaouche, A.; Beslier, M.; Bracene, R.; Philippe, S.; Djellit, H.; Galve, A.; Bounif, A.; Schenini, L.; Sage, F.; Charvis, P.

2013-12-01

During the Algerian-French SPIRAL cruise (Sismique Profonde et Investigation Régionale du Nord de l'Algérie) conducted onboard R/V Atalante (September-October 2009), one deep reflection and wide-angle seismic profile with total length of 140 km was acquired on the Algerian margin, offshore Greater Kabylia. 40 ocean bottom seismometers (OBS) were deployed on the profile, located perpendicular to the margin and it was additionally extended on land using 26 seismological stations. A 8350 in3 tuned air-gun array consisting of 10 Bolt air-guns was used to generate deep frequency shots to allow for a good penetration. A coincident multi-channel seismic profile was acquired using a 3040 in3 seismic source and a 4.5 km 360 channel digital seismic streamer. Underway geophysical measurements included gravimetric and magnetic data. The combined profile with a total length of about 260 km, crosses from north to south the Algero-Provençal basin, the central Algerian margin and onshore the crystalline basement of the Kabylides bloc up to the southward limit of the internal zones. We present results concerning the sedimentary and crustal structures in the study area using tomographic inversion, forward and gravimetric modelling. Modelling of the wide-angle and multi-channel seismic data reveals that the thickness of the sedimentary cover along the profile varies from several hundreds of metres onland in Tiziouzou basin (R. Bracéne 2001), to ~4 km at the foot of the margin and then decreasing northward to less than 3 km. The Messinian evaporitic units have been modelled by a high velocity layer, representing a velocity inversion with underlying pre-Messinian Miocene sedimentary layers. Progressive thinning of the continental crust towards the North is observed, with thicknesses decreasing from ~20 km at the foot of the margin to 4-5 km in the deep basin. Seismic velocities range between 6.2 and 6.6 km/s in the continental domain and 5.2 - 6.8 km/s in the deep basin. The uppermost crust of the deep margin is characterised by low velocities of only 4.5-5.0 km/s probably due to fracturing during the thinning of the crust. The transition between continental crust and crust of oceanic origin is located about 60 km from the coast. Its extension is very narrow (< 20 km) with a possibility of it being absent in this region. The crust underlying the basin at the foot of the continental slope is characterised by a thickness of only 3-5 km which is about 2 km thinner than normal oceanic crust. Seismic velocities however indicate that the crust is of oceanic origin and does not represent exhumed and partly serpentinised mantle material, although the presence of small amounts of mantle material in an otherwise igneous crust cannot be ruled out. Similar thin oceanic crust has been imaged in other Mediterranean Basins, such as the Liguro-Provençal basin (Gailler et al., 2009).

Interaction of surface water and groundwater in the Nile River basin: isotopic and piezometric evidence

NASA Astrophysics Data System (ADS)

Kebede, Seifu; Abdalla, Osman; Sefelnasr, Ahmed; Tindimugaya, Callist; Mustafa, Osman

2017-05-01

Past discussions around water-resources management and development in the River Nile basin disregard groundwater resources from the equation. There is an increasing interest around factoring the groundwater resources as an integral part of the Nile Basin water resources. This is hampered by knowledge gap regarding the groundwater resources dynamics (recharge, storage, flow, quality, surface-water/groundwater interaction) at basin scale. This report provides a comprehensive analysis of the state of surface-water/groundwater interaction from the headwater to the Nile Delta region. Piezometric and isotopic (δ18O, δ2H) evidence reveal that the Nile changes from a gaining stream in the headwater regions to mostly a loosing stream in the arid lowlands of Sudan and Egypt. Specific zones of Nile water leakage to the adjacent aquifers is mapped using the two sources of evidence. Up to 50% of the surface-water flow in the equatorial region of the Nile comes from groundwater as base flow. The evidence also shows that the natural direction and rate of surface-water/groundwater interaction is largely perturbed by human activities (diversion, dam construction) particularly downstream of the Aswan High Dam in Egypt. The decrease in discharge of the Nile River along its course is attributed to leakage to the aquifers as well as to evaporative water loss from the river channel. The surface-water/groundwater interaction occurring along the Nile River and its sensitivity to infrastructure development calls for management strategies that account groundwater as an integral part of the Nile Basin resources.

West Nile virus

MedlinePlus

... of standing water, such as trash bins and plant saucers (mosquitos breed in stagnant water) Community spraying for mosquitoes may also reduce mosquito breeding. Alternative Names Encephalitis - West Nile; Meningitis - West Nile ...

Intraspecific variation in gill morphology of juvenile Nile perch, Lates niloticus, in Lake Nabugabo, Uganda

USGS Publications Warehouse

Paterson, Jaclyn A.; Chapman, Lauren J.; Schofield, Pamela J.

2010-01-01

Several studies have demonstrated intraspecific variation in fish gill size that relates to variation in dissolved oxygen (DO) availability across habitats. In Lake Nabugabo, East Africa, ecological change over the past 12 years has coincided with a shift in the distribution of introduced Nile perch such that a larger proportion of the population now inhabits waters in or near wetland ecotones where DO is lower than in open waters of the lake. In this study, we compared gill size of juvenile Nile perch between wetland and exposed (open-water) habitats of Lake Nabugabo in 2007, as well as between Nile perch collected in 1996 and 2007. For Nile perch of Lake Nabugabo [<20 cm total length (TL)], there was a significant habitat effect on some gill traits. In general, fish from wetland habitats were characterized by a longer total gill filament length and average gill filament length than conspecifics from exposed habitats. Nile perch collected from wetland areas in 2007 had significantly larger gills (total gill filament length) than Nile perch collected in 1996, but there was no difference detected between Nile perch collected from exposed sites in 2007 and conspecifics collected in 1996.

Gating mass cytometry data by deep learning.

PubMed

Li, Huamin; Shaham, Uri; Stanton, Kelly P; Yao, Yi; Montgomery, Ruth R; Kluger, Yuval

2017-11-01

Mass cytometry or CyTOF is an emerging technology for high-dimensional multiparameter single cell analysis that overcomes many limitations of fluorescence-based flow cytometry. New methods for analyzing CyTOF data attempt to improve automation, scalability, performance and interpretation of data generated in large studies. Assigning individual cells into discrete groups of cell types (gating) involves time-consuming sequential manual steps, untenable for larger studies. We introduce DeepCyTOF, a standardization approach for gating, based on deep learning techniques. DeepCyTOF requires labeled cells from only a single sample. It is based on domain adaptation principles and is a generalization of previous work that allows us to calibrate between a target distribution and a source distribution in an unsupervised manner. We show that DeepCyTOF is highly concordant (98%) with cell classification obtained by individual manual gating of each sample when applied to a collection of 16 biological replicates of primary immune blood cells, even when measured across several instruments. Further, DeepCyTOF achieves very high accuracy on the semi-automated gating challenge of the FlowCAP-I competition as well as two CyTOF datasets generated from primary immune blood cells: (i) 14 subjects with a history of infection with West Nile virus (WNV), (ii) 34 healthy subjects of different ages. We conclude that deep learning in general, and DeepCyTOF specifically, offers a powerful computational approach for semi-automated gating of CyTOF and flow cytometry data. Our codes and data are publicly available at https://github.com/KlugerLab/deepcytof.git. yuval.kluger@yale.edu. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Earth Observations taken by the Expedition 10 crew

NASA Image and Video Library

2005-04-07

ISS010-E-23451 (7 April 2005) --- Khartoum, Sudan is featured in this image photographed by an Expedition 10 crewmember on the International Space Station (ISS). Sudan’s capital city Khartoum, which means Elephant’s Trunk, describes the shape of the Nile River where the Blue and the White Nile Rivers meet to form the united Nile that flows northward into Egypt. This image shows the rivers near the end of the dry season. The White Nile (western branch) runs through Sudan from Uganda. The White Nile’s equatorial source produces a flow that runs at a nearly constant rate throughout the year. The nearly dry Blue Nile from the highlands of Ethiopia swells in the late summer and early fall with rains from the summer monsoons. The flow can be so great the Nile flows backward at the junction. In recent years, floods in Khartoum have occurred in August with heavy monsoon rainfall. Khartoum is one of the largest Muslim cities in North Africa, but has a fairly short history.

Malaria (For Parents)

MedlinePlus

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Authigenic Carbonate Formation on the Peru Margin; New Insights from IODP Site 1230

NASA Astrophysics Data System (ADS)

Abdullajintakam, S.; Naehr, T. H.

2015-12-01

Fluid seepage of reduced organic compounds such as methane impacts the geology and biology of the seabed by inducing complex, microbially mediated biogeochemical processes. Authigenic carbonates serve as one of the few permanent records of these of dynamic biogeochemical interactions that involve methanogenesis, methanotrophy, sulfate reduction and carbonate precipitation. Meister et al. (2007) investigated deep-sea dolomite formation at Sites 1227-1229 on the Peru margin, where dolomite precipitation occurs in association with organic carbon-rich continental margin sediments. Geochemical and petrographic studies indicated episodic dolomite precipitation at a dynamic sulfate methane transition zone (SMTZ). Variations in δ13C values of these dolomites between +15‰ and -15‰ were attributed to non-steady state conditions as a result of the upward and downward migration of the SMTZ. Our study aims to better understand the biogeochemical processes associated with authigenic carbonate precipitation in this dynamic deep-sea setting. We focused our efforts on IODP Site 1230, which is a gas-hydrate-bearing site that shows sulphate consumption within the uppermost 10 m below the seafloor as well as high methane production. Using a multi proxy approach, we combined X-ray diffraction, stable isotope geochemistry, and trace metal analysis of authigenic carbonates to elucidate conditions for authigenic carbonate formation. Results from Site 1230 are compared to Sites 1227 and 1229, which lacks gas hydrates and is characterized by high pore water sulfate and low methane concentrations. This study contributes to a more comprehensive understanding of authigenic carbonate formation and associated biogeochemical processes in continental margin sediments. Meister, P., Mckenzie, J. A., Vasconcelos, C., Bernasconi, S., Frank, M., Gutjhar, M. and SCHRAG, D. P. (2007), Dolomite formation in the dynamic deep biosphere: results from the Peru Margin. Sedimentology, 54: 1007-1032.

Carbonate sedimentation in an extensional active margin: Cretaceous history of the Haymana region, Pontides

NASA Astrophysics Data System (ADS)

Okay, Aral I.; Altiner, Demir

2016-10-01

The Haymana region in Central Anatolia is located in the southern part of the Pontides close to the İzmir-Ankara suture. During the Cretaceous, the region formed part of the south-facing active margin of the Eurasia. The area preserves a nearly complete record of the Cretaceous system. Shallow marine carbonates of earliest Cretaceous age are overlain by a 700-m-thick Cretaceous sequence, dominated by deep marine limestones. Three unconformity-bounded pelagic carbonate sequences of Berriasian, Albian-Cenomanian and Turonian-Santonian ages are recognized: Each depositional sequence is preceded by a period of tilting and submarine erosion during the Berriasian, early Albian and late Cenomanian, which corresponds to phases of local extension in the active continental margin. Carbonate breccias mark the base of the sequences and each carbonate sequence steps down on older units. The deep marine carbonate deposition ended in the late Santonian followed by tilting, erosion and folding during the Campanian. Deposition of thick siliciclastic turbidites started in the late Campanian and continued into the Tertiary. Unlike most forearc basins, the Haymana region was a site of deep marine carbonate deposition until the Campanian. This was because the Pontide arc was extensional and the volcanic detritus was trapped in the intra-arc basins and did not reach the forearc or the trench. The extensional nature of the arc is also shown by the opening of the Black Sea as a backarc basin in the Turonian-Santonian. The carbonate sedimentation in an active margin is characterized by synsedimentary vertical displacements, which results in submarine erosion, carbonate breccias and in the lateral discontinuity of the sequences, and differs from blanket like carbonate deposition in the passive margins.

13.000 years of multicentennial variability in Nile discharge: The link between solar activity, Indian monsoon, and Sapropel S1 formation

NASA Astrophysics Data System (ADS)

Hennekam, Rick; Jilbert, Tom; Schnetger, Bernhard; De Lange, Gert J.

2014-05-01

Sediments in the southeast Mediterranean are characterized by high accumulation rates, being influenced by suspended matter from the Nile plume. Therefore, the sediments from this area offer an invaluable high-resolution climate archive. Earlier work has shown that Nile River outflow has influenced water chemistry in this region throughout the entire Holocene, being well recorded in the oxygen isotopic ratio of the planktic foraminifer Globigerinoides ruber (δ18Oruber). The deposition of organic-rich layers (sapropels) during precession minima is often linked to Nile discharge. Here we present a multi-proxy study of a well-dated sediment core from the southeast Mediterranean basin to study in high-resolution the variability in Nile discharge during the early- to mid-Holocene. High sedimentation rates and sample resolution allow for recognition of (multi-)centennial variability in Nile discharge as recorded by δ18Oruber. Moreover, we measured bulk sediment Ba/Al (representing export-productivity), V/Al (representing redox conditions), and total organic carbon (Corg) during deposition of sapropel S1 (~6-10 kyr BP). Nile discharge is influenced by moisture transport from both the Atlantic and Indian Oceans, being presently dominated by Atlantic moisture. We show that Nile discharge during the early- to mid-Holocene was dominated by Indian Ocean moisture transport. This is supported by the maximum in Nile discharge at ~9.5 cal. kyr BP, similar to the maximum intensity of Indian Ocean-influenced southwest Indian summer monsoon. Moreover, the strong solar activity signal observed in multi-centennial oscillations in Nile discharge during this time interval concords with those recorded in contemporaneous Indian Ocean-derived monsoon records, but not with those from the Atlantic Ocean. Solar-induced variability in Nile discharge also influenced the conditions relating to Sapropel S1 formation. During its deposition, similar multi-centennial variability is found in bulk sediment Ba/Al, V/Al, and Corg, indicating that nutrient availability and shallow water column ventilation in the eastern Mediterranean were sensitive to Nile discharge.

Comprehensive evaluation of immunomodulation by moderate hypoxia in S. agalactiae vaccinated Nile tilapia.

PubMed

Gallage, Sanchala; Katagiri, Takayuki; Endo, Masato; Maita, Masashi

2017-07-01

Streptococcus agalactiae is a major bacterial pathogen in tilapia aquaculture. Vaccines are known to provide protection but S. agalactiae clearance in tilapia can be reduced by marginal environmental conditions. Therefore, the purpose of this study is to examine S. agalactiae clearance in vaccinated Nile tilapia under moderate hypoxic (55± 5% DO) and normoxic (85 ± 5%DO) conditions. Fish were acclimatized to either moderate hypoxia or normoxia and immunized with formalin-inactivated S. agalactiae. Fish were experimentally challenged with S. agalactiae at 30 days post-vaccination. Serum antibody titer was significantly higher in vaccinated fish kept under normoxic condition compared to the moderate hypoxic condition at fifteen and thirty days post-vaccination. The cumulative mortality following challenge was significantly reduced in vaccinated fish kept under normoxic condition compared to those in moderate hypoxic condition reflecting that pre-challenge antibody titer may correlate with survival of fish. Blood and tissue pathogen burden detection of S. agalactiae studies revealed that culturable S. agalactiae cells could not be detected in the blood of normoxic vaccinated fish at all the sampling points. In contrast, fish vaccinated in moderate hypoxic condition had considerable number of culturable S. agalactiae cells in their blood up to 5 days following challenge. Phagocytosis and intracellular reactive oxygen species (ROS) production were lowered by moderate hypoxia in vitro. Furthermore, presence of specific antibodies and higher specific antibody level in the serum increased phagocytosis, ROS production and lowered intracellular survival of S. agalactiae in head kidney leukocytes. Overall this study has highlighted that S. agalactiae clearance in vaccinated Nile tilapia is modulated by moderate hypoxia. One of the possible explanations for this might be less efficient phagocytic activities due to low oxygen availability and lower specific antibody production in vaccinated fish. Copyright © 2017 Elsevier Ltd. All rights reserved.

A study of West Nile virus infection in Iranian blood donors.

PubMed

Sharifi, Zohreh; Mahmoodian Shooshtari, Mahmood; Talebian, Ali

2010-01-01

West Nile virus is a mosquito transmitted virus that can cause disease in humans and horses. A majority of people infected with WNV will have no symptoms or may only experience mild symptoms, such as headaches. About 20% of infected humans develop a flu-like illness characterized by fever; while in the elderly and immunocompromised West Nile virus can cause a more serious neurologic disease and may be fatal. West Nile virus infection is endemic in the Middle East. West Nile virus can also be transmitted by transfusion through infected blood components.The objective of this study is to find the West Nile virus-RNA incidence and anti-West Nile virus prevalence amongst Iranian blood donors in order to determine whether this emerging infection is a possible risk for the blood supply in Iran. Serum samples from 500 blood donors who donated blood at the Tehran Blood Transfusion Center were collected between May and October 2005. Serum samples were examined for IgM and IgG antibodies to West Nile virus using the ELISA method. The samples were tested for the presence of West Nile virus RNA by the real-time RT-polymerase chain reaction assay. All data were analyzed statistically using the Chi-Square test. All 500 donors were negative for West Nile virus-specific IgM antibody at the time of donation. No WNV RNA-positive samples were detected. The percentage of seropositivity of IgG antibodies to WNV was 5% at donation. No evidence of WNV-specific IgM antibody and WNV RNA in blood donor samples was found. In order to increase the safety of blood donation, it is essential to continue surveillance of this emerging infection in order to protect the blood supply in the future.

Rifting and Subsidence in the Gulf of Mexico: Implications for Syn-rift, Sag, and Salt Sections, and Subsequent Paleogeography

NASA Astrophysics Data System (ADS)

Pindell, J. L.; Graham, R.; Horn, B.

2013-05-01

Thick (up to 5 km), rapid (<3 Ma), salt deposition is problematic for basin modelling because such accommodation cannot be thermal, yet GoM salt deposits (Late Callovian-Early Oxfordian) appear to be post-rift (most salt overlies planar sub-salt unconformities on syn-rift section). One possible solution is that the pre-drift GoM was a deep (~2 km) air-filled rift depression where basement had already subsided tectonically, and thus could receive up to 5 km of salt, roughly the isostatic maximum on exhumed mantle, hyper-thinned continent, or new ocean crust. ION-GXT and other seismic data along W Florida and NW Yucatán show that (1) mother salt was only 1 km thick in these areas, (2) that these areas were depositionally connected to areas of thicker deposition, and (3) the top of all salt was at global sea level, and hence the sub-salt unconformity along Florida and Yucatán was only 1 km deep by end of salt deposition. These observations fit the air-filled chasm hypothesis; however, two further observations make that mechanism highly improbable: (1) basinward limits of sub-salt unconformities along Florida/Yucatán are deeper than top of adjacent ocean crust emplaced at ~2.7 km subsea (shown by backstripping), and (2) deepest abyssal sediments over ocean crust onlap the top of distal salt, demonstrating that the salt itself was rapidly drowned after deposition. Study of global ION datasets demonstrates the process of "rapid outer marginal collapse" at most margins, which we believe is achieved by low-angle detachment on deep, landward-dipping, Moho-equivalent surfaces such that outer rifted margins are hanging walls of crustal scale half-grabens over mantle. The tectonic accommodation space produced (up to 3 km, < 3 Ma) can be filled by ~5 km of sag/salt sequences with little apparent hanging wall rifting. When salt (or other) deposition lags behind, or ends during, outer marginal collapse, deep-water settings result. We suggest that this newly identified, "outer marginal detachment phase", normally separates the traditional "rift" from "drift" stages during continental margin creation. Importantly, this 2-3 km of subsidence presently is neither treated as tectonic nor as thermal in traditional subsidence analysis; thus, Beta estimates may be excessive at many outer margins. Outer marginal collapse was probably eastwardly diachronous with initiation of spreading in the GoM. Additionally, recent paleo-climate studies suggest humid Early/Middle Jurassic conditions in equatorial GoM, hindering air-filled chasm development, but North America's northward flight into middle latitudes initiated Callovian aridity.

Crustal Structure of the Ionian Basin and Eastern Sicily Margin: Results From a Wide-Angle Seismic Survey

NASA Astrophysics Data System (ADS)

Dellong, David; Klingelhoefer, Frauke; Kopp, Heidrun; Graindorge, David; Margheriti, Lucia; Moretti, Milena; Murphy, Shane; Gutscher, Marc-Andre

2018-03-01

In the Ionian Sea (central Mediterranean) the slow convergence between Africa and Eurasia results in the formation of a narrow subduction zone. The nature of the crust of the subducting plate remains debated and could represent the last remnants of the Neo-Tethys ocean. The origin of the Ionian basin is also under discussion, especially concerning the rifting mechanisms as the Malta Escarpment could represent a remnant of this opening. This subduction retreats toward the south-east (motion occurring since the last 35 Ma) but is confined to the narrow Ionian basin. A major lateral slab tear fault is required to accommodate the slab roll-back. This fault is thought to propagate along the eastern Sicily margin but its precise location remains controversial. This study focuses on the deep crustal structure of the eastern Sicily margin and the Malta Escarpment. We present two two-dimensional P wave velocity models obtained from forward modeling of wide-angle seismic data acquired onboard the R/V Meteor during the DIONYSUS cruise in 2014. The results image an oceanic crust within the Ionian basin as well as the deep structure of the Malta Escarpment, which presents characteristics of a transform margin. A deep and asymmetrical sedimentary basin is imaged south of the Messina strait and seems to have opened between the Calabrian and Peloritan continental terranes. The interpretation of the velocity models suggests that the tear fault is located east of the Malta Escarpment, along the Alfeo fault system.

The first human case of neuroinvasive West Nile virus infection identified in Cyprus.

PubMed

Paphitou, Niki I; Tourvas, Aristomenis; Floridou, Dora; Richter, Jan; Tryfonos, Christina; Christodoulou, Christina

West Nile virus infection can pose a diagnostic challenge to clinicians, especially in geographic areas where human cases of this disease have never been encountered before. In August 2016, the first human case of West Nile virus infection was diagnosed in Cyprus. An elderly non immunosuppressed patient with a history of recent travel, presented with a clinical picture of rapidly progressing ascending paralysis mimicking Guillain-Barré syndrome. Neuroinvasive West Nile virus disease was diagnosed by detecting West Nile virus nucleic acid in the patient's cerebrospinal fluid. Public health measures were taken raising awareness regarding this disease and its prevention. Clinical vigilance to consider West Nile virus as a possible emerging pathogen in the appropriate clinical setting is warranted and could benefit individual patients. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Explaining and forecasting interannual variability in the flow of the Nile River

NASA Astrophysics Data System (ADS)

Siam, M. S.; Eltahir, E. A. B.

2014-05-01

The natural interannual variability in the flow of Nile River had a significant impact on the ancient civilizations and cultures that flourished on the banks of the river. This is evident from stories in the Bible and Koran, and from the numerous Nilometers discovered near ancient temples. Here, we analyze extensive data sets collected during the 20th century and define four modes of natural variability in the flow of Nile River, identifying a new significant potential for improving predictability of floods and droughts. Previous studies have identified a significant teleconnection between the Nile flow and the Eastern Pacific Ocean. El Niño-Southern Oscillation (ENSO) explains about 25% of the interannual variability in the Nile flow. Here, we identify, for the first time, a region in the southern Indian Ocean with similarly strong teleconnection to the Nile flow. Sea Surface Temperature (SST) in the region (50-80° E and 25-35° S) explains 28% of the interannual variability in the Nile flow. During those years with anomalous SST conditions in both Oceans, we estimate that indices of the SSTs in the Pacific and Indian Oceans can collectively explain up to 84% of the interannual variability in the flow of Nile. Building on these findings, we use classical Bayesian theorem to develop a new hybrid forecasting algorithm that predicts the Nile flow based on global models predictions of indices of the SST in the Eastern Pacific and Southern Indian Oceans.

Mesozoic carbonate-siliciclastic platform to basin systems of a South Tethyan margin (Egypt, East Mediterranean)

NASA Astrophysics Data System (ADS)

Tassy, Aurélie; Crouzy, Emmanuel; Gorini, Christian; Rubino, Jean-Loup

2015-04-01

The Mesozoïc Egyptian margin is the south margin of a remnant of the Neo-Tethys Ocean, at the African northern plate boundary. East Mediterranean basin developed during the late Triassic-Early Jurassic rifting with a NW-SE opening direction (Frizon de Lamotte et al., 2011). During Mesozoïc, Egypt margin was a transform margin with a NW-SE orientation of transform faults. In the Eastern Mediterranean basin, Mesozoïc margins are characterized by mixed carbonate-siliciclastics platforms where subsidence and eustacy are the main parameters controlling the facies distribution and geometries of the platform-to-basin transition. Geometries and facies on the platform-slope-basin system, today well constrained on the Levant area, where still poorly known on the Egyptian margin. Geometries and stratigraphic architecture of the Egyptian margin are revealed, thanks to a regional seismic and well data-base provided by an industrial-academic group (GRI, Total). The objective is to understand the sismostratigraphic architecture of the platform-slope-basin system in a key area from Western Desert to Nile delta and Levant margin. Mapping of the top Jurassic and top Cretaceous show seismic geomorphology of the margin, with the cartography of the hinge line from Western Desert to Sinaï. During the Jurassic, carbonate platform show a prograding profile and a distally thickening of the external platform, non-abrupt slope profiles, and palaeovalleys incisions. Since the Cretaceous, the aggrading and retrograding mixed carbonate-siliciclastic platform show an alternation of steep NW-SE oblique segments and distally steepened segments. These structures of the platform edge are strongly controlled by the inherited tethyan transform directions. Along the hinge line, embayments are interpreted as megaslides. The basin infilling is characterised by an alternation of chaotic seismic facies and high amplitude reflectors onlaping the paleoslopes. MTC deposits can mobilize thick sedimentary series (up to 3500 m) as a mixed combination of debris flows, internal preserved blocks, and/or compressively-deformed distal allochthonous masses. Transported material have proceeded from the dismantling of the Mesozoic mixed carbonate-siliciclastic platform. They can spread down slope over areas as large as 70000 of km2. According to stratigraphic correlations with global sea-level positions, platform instability would have been triggered by the gravitational collapse of the carbonate-siliciclastic platform under its own weight after successive subaerial exposures which were able to generate karstification processes. Seismic interpretation is constrained by a detailed assessment of the Egyptian margin paleogeography supported by wells. This margin segment is briefly compared to the outcropping Apulian margin in Italy.

The Ebro margin study, northwestern Mediterranean Sea - an introduction

USGS Publications Warehouse

Maldonado, A.; Hans, Nelson C.

1990-01-01

The Ebro continental margin from the coast to the deep sea off northeastern Spain was selected for a multidisciplinary project because of the abundant Ebro River sediment supply, Pliocene and Quaternary progradation, and margin development in a restricted basin where a variety of controlling factors could be evaluated. The nature of this young passive margin for the last 5 m.y. was investigated with particular emphasis on marine circulation, sediment dynamics, sediment geochemistry, depositional facies, seismic stratigraphy, geotechnical properties, geological hazards and human influences. These studies show the importance of marine circulation, variation in sediment supply, sea-level oscillation and tectonic setting for the understanding of modern and ancient margin depositional processes and growth patterns. ?? 1990.

Natural equilibria and anthropic effects on sediment transport in big river systems: The Nile case

NASA Astrophysics Data System (ADS)

Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Vezzoli, Giovanni; Villa, Igor

2014-05-01

The Nile River flows for ~ 6700 km, from Burundi and Rwanda highlands south of the Equator to the Mediterranean Sea at northern subtropical latitudes. It is thus the longest natural laboratory on Earth, a unique setting in which we are carrying out a continuing research project to investigate changes in sediment composition associated with a variety of chemical and physical processes, including weathering in equatorial climate and hydraulic sorting during transport and deposition. Petrographic, mineralogical, chemical, and isotopic fingerprints of sand and mud have been monitored along all Nile branches, from the Kagera and White Nile draining Archean, Paleoproterozoic and Mesoproterozoic basements uplifted along the western branch of the East African rift, to the Blue Nile and Atbara Rivers sourced in Ethiopian volcanic highlands made of Oligocene basalt. Downstream of the Atbara confluence, the Nile receives no significant tributary water and hardly any rainfall across the Sahara. After construction of the Aswan High Dam in 1964, the Nile ceased to be an active conveyor-belt in Egypt, where the mighty river has been tamed to a water canal; transported sediments are thus chiefly reworked from older bed and levee deposits, with minor contributions from widyan sourced in the Red Sea Hills and wind-blown desert sand and dust. Extensive dam construction has determined a dramatic sediment deficit at the mouth, where deltaic cusps are undergoing ravaging erosion. Nile delta sediments are thus recycled under the effect of dominant waves from the northwest, the longest Mediterranean fetch direction. Nile sands, progressively enriched in more stable minerals such as quartz and amphiboles relative to volcanic rock fragments and pyroxene, thus undergo multistep transport by E- and NE-directed longshore currents all along the coast of Egypt and Palestine, and are carried as far as Akko Bay in northern Israel. Nile mud reaches the Iskenderun Gulf in southern Turkey. A full knowledge of the Nile sediment system not only has wide paleoclimatic, paleoceanographic and archaeological implications, including a better understanding of Quaternary environmental changes in northern Africa, water circulation and sapropel development in the Mediterranean Sea, and impact on the Egyptian civilization by natural phenomena, but is also strongly needed to mitigate undesirable impacts of human activities on natural equilibria and to improve watershed, reservoir and coastal management. Mineralogical data (Shukri, 1950) integrated by new petrographic, heavy-mineral and geochemical analyses (Padoan et al., 2011) show how sediments derived from Archean gneisses exposed through northern Uganda and from Panafrican basements drained by Ethiopian tributaries of River Sobat become progressively enriched in quartz at the expense of unstable components across the Sudd and Machar Marshes (grey shaded area). Petrographic, mineralogical, and isotopic signatures are gradually homogenized along both the Bahr el Jebel/Bahr ez Zeraf and the Sobat and remain finally unchanged down to Khartoum, which suggests massive sediment dumping in the marshes. This explains why White Nile sediment contribution to the main Nile downstream Khartoum is virtually negligible (Garzanti et al., 2006). 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. Padoan, M., Garzanti, E., Harlavan, Y., Villa, I.M., 2011. Tracing Nile sediment sources by Sr and Nd isotope signatures (Uganda, Ethiopia, Sudan). Geochim. Cosmochim. Acta, 75, 3627-3644. Said, R., 1993. The River Nile, Oxford, Pergamon, 1993, 320 p. Shukri, N.M., 1950. The mineralogy of some Nile sediments. Quart. J. Geol. Soc. London, 105, 511-534. Williams, M.A.J., Faure, H., 1980. The Sahara and the Nile. Balkema, Rotterdam. Woodward, J.C., Macklin, M.G., Krom, M.D., Williams, M.A.J., 2007. The Nile: Evolution, quaternary river environments and material fluxes. In: Large Rivers: Geomorphology and Management, Avijit Gupta (Ed.), John Wiley and Sons, ch. 13, 261-292.

Polychlorinated Biphenyls Water Pollution along the River Nile, Egypt

PubMed Central

Megahed, Ayman Mohamed; Dahshan, Hesham; Abd-El-Kader, Mahdy A.; Abd-Elall, Amr Mohamed Mohamed; Elbana, Mariam Hassan; Nabawy, Ehab; Mahmoud, Hend A.

2015-01-01

Ten polychlorinated biphenyl (PCB) congeners were determined in water samples collected along the River Nile using gas chromatography-electron capture detector (GC-ECD). PCB concentrations ranged from 14 to 20 μg/L, which were higher than those reported in previous studies, indicating serious PCB pollution in the River Nile. PCB congener profiles varied depending on the sampling sties. PCB-138 was the predominant congener accounting for more than 18% of total PCBs. The composition of PCB congeners in the water revealed that highly chlorinated PCB technical mixtures such as Aroclor 1254 was the main PCB production historically used in Egypt. An increasing trend in PCB levels from the upper stream to the Nile estuaries was observed. The calculated flux of PCBs indicated that 6.8 tons of PCBs is dumped into the Mediterranean Sea each year from the River Nile. The hazard quotients and carcinogenic risk caused by PCB pollution in the River Nile were above the acceptable level indicating that PCBs in the River Nile water pose adverse health effects for all age groups. Our findings revealed that PCBs possess a serious risk to the Egyptian population that depends mainly on the River Nile as a source of water. Thus, stricter legislation and regulatory controls should be applied to reduce the risk of PCBs in Egypt. PMID:26798844

Fusion loop peptide of the West Nile virus envelope protein is essential for pathogenesis and is recognized by a therapeutic cross-reactive human monoclonal antibody.

PubMed

Sultana, Hameeda; Foellmer, Harald G; Neelakanta, Girish; Oliphant, Theodore; Engle, Michael; Ledizet, Michel; Krishnan, Manoj N; Bonafé, Nathalie; Anthony, Karen G; Marasco, Wayne A; Kaplan, Paul; Montgomery, Ruth R; Diamond, Michael S; Koski, Raymond A; Fikrig, Erol

2009-07-01

West Nile virus is an emerging pathogen that can cause fatal neurological disease. A recombinant human mAb, mAb11, has been described as a candidate for the prevention and treatment of West Nile disease. Using a yeast surface display epitope mapping assay and neutralization escape mutant, we show that mAb11 recognizes the fusion loop, at the distal end of domain II of the West Nile virus envelope protein. Ab mAb11 cross-reacts with all four dengue viruses and provides protection against dengue (serotypes 2 and 4) viruses. In contrast to the parental West Nile virus, a neutralization escape variant failed to cause lethal encephalitis (at higher infectious doses) or induce the inflammatory responses associated with blood-brain barrier permeability in mice, suggesting an important role for the fusion loop in viral pathogenesis. Our data demonstrate that an intact West Nile virus fusion loop is critical for virulence, and that human mAb11 targeting this region is efficacious against West Nile virus infection. These experiments define the molecular determinant on the envelope protein recognized by mAb11 and demonstrate the importance of this region in causing West Nile encephalitis.

Detection and sequencing of West Nile virus RNA from human urine and serum samples during the 2014 seasonal period.

PubMed

Nagy, Anna; Bán, Enikő; Nagy, Orsolya; Ferenczi, Emőke; Farkas, Ágnes; Bányai, Krisztián; Farkas, Szilvia; Takács, Mária

2016-07-01

West Nile virus, a widely distributed mosquito-borne flavivirus, is responsible for numerous animal and human infections in Europe, Africa and the Americas. In Hungary, the average number of human infections falls between 10 and 20 cases each year. The severity of clinically manifesting infections varies widely from the milder form of West Nile fever to West Nile neuroinvasive disease (WNND). In routine laboratory diagnosis of human West Nile virus infections, serological methods are mainly applied due to the limited duration of viremia. However, recent studies suggest that detection of West Nile virus RNA in urine samples may be useful as a molecular diagnostic test for these infections. The Hungarian National Reference Laboratory for Viral Zoonoses serologically confirmed eleven acute human infections during the 2014 seasonal period. In three patients with neurological symptoms, viral RNA was detected from both urine and serum specimens, albeit for a longer period and in higher copy numbers with urine. Phylogenetic analysis of the NS3 genomic region of three strains and the complete genome of one selected strain demonstrated that all three patients had lineage-2 West Nile virus infections. Our findings reaffirm the utility of viral RNA detection in urine as a molecular diagnostic procedure for diagnosis of West Nile virus infections.

What's West Nile Virus?

MedlinePlus

... for Educators Search English Español What's West Nile Virus? KidsHealth / For Kids / What's West Nile Virus? Print en español ¿Qué es el Virus del Nilo Occidental? What exactly is the West ...

West Nile Virus: Symptoms and Treatment

MedlinePlus

... U V W X Y Z # West Nile virus Note: Javascript is disabled or is not supported ... visit this page: About CDC.gov . West Nile Virus Home Prevention Prevención y control Symptoms, Diagnosis, & Treatment ...

Climate change enhances interannual variability of the Nile river flow

NASA Astrophysics Data System (ADS)

Siam, Mohamed S.; Eltahir, Elfatih A. B.

2017-04-01

The human population living in the Nile basin countries is projected to double by 2050, approaching one billion. The increase in water demand associated with this burgeoning population will put significant stress on the available water resources. Potential changes in the flow of the Nile River as a result of climate change may further strain this critical situation. Here, we present empirical evidence from observations and consistent projections from climate model simulations suggesting that the standard deviation describing interannual variability of total Nile flow could increase by 50% (+/-35%) (multi-model ensemble mean +/- 1 standard deviation) in the twenty-first century compared to the twentieth century. We attribute the relatively large change in interannual variability of the Nile flow to projected increases in future occurrences of El Niño and La Niña events and to observed teleconnection between the El Niño-Southern Oscillation and Nile River flow. Adequacy of current water storage capacity and plans for additional storage capacity in the basin will need to be re-evaluated given the projected enhancement of interannual variability in the future flow of the Nile river.

Nile Red Detection of Bacterial Hydrocarbons and Ketones in a High-Throughput Format

PubMed Central

Pinzon, Neissa M.; Aukema, Kelly G.; Gralnick, Jeffrey A.; Wackett, Lawrence P.

2011-01-01

ABSTRACT A method for use in high-throughput screening of bacteria for the production of long-chain hydrocarbons and ketones by monitoring fluorescent light emission in the presence of Nile red is described. Nile red has previously been used to screen for polyhydroxybutyrate (PHB) and fatty acid esters, but this is the first report of screening for recombinant bacteria making hydrocarbons or ketones. The microtiter plate assay was evaluated using wild-type and recombinant strains of Shewanella oneidensis and Escherichia coli expressing the enzyme OleA, previously shown to initiate hydrocarbon biosynthesis. The strains expressing exogenous Stenotrophomonas maltophilia oleA, with increased levels of ketone production as determined by gas chromatography-mass spectrometry, were distinguished with Nile red fluorescence. Confocal microscopy images of S. oneidensis oleA-expressing strains stained with Nile red were consistent with a membrane localization of the ketones. This differed from Nile red staining of bacterial PHB or algal lipid droplets that showed intracellular inclusion bodies. These results demonstrated the applicability of Nile red in a high-throughput technique for the detection of bacterial hydrocarbons and ketones. PMID:21712420

Deep continental margin reflectors

USGS Publications Warehouse

Ewing, J.; Heirtzler, J.; Purdy, M.; Klitgord, Kim D.

1985-01-01

In contrast to the rarity of such observations a decade ago, seismic reflecting and refracting horizons are now being observed to Moho depths under continental shelves in a number of places. These observations provide knowledge of the entire crustal thickness from the shoreline to the oceanic crust on passive margins and supplement Consortium for Continental Reflection Profiling (COCORP)-type measurements on land.

Marginal Shape Deep Learning: Applications to Pediatric Lung Field Segmentation.

PubMed

Mansoor, Awais; Cerrolaza, Juan J; Perez, Geovanny; Biggs, Elijah; Nino, Gustavo; Linguraru, Marius George

2017-02-11

Representation learning through deep learning (DL) architecture has shown tremendous potential for identification, localization, and texture classification in various medical imaging modalities. However, DL applications to segmentation of objects especially to deformable objects are rather limited and mostly restricted to pixel classification. In this work, we propose marginal shape deep learning (MaShDL), a framework that extends the application of DL to deformable shape segmentation by using deep classifiers to estimate the shape parameters. MaShDL combines the strength of statistical shape models with the automated feature learning architecture of DL. Unlike the iterative shape parameters estimation approach of classical shape models that often leads to a local minima, the proposed framework is robust to local minima optimization and illumination changes. Furthermore, since the direct application of DL framework to a multi-parameter estimation problem results in a very high complexity, our framework provides an excellent run-time performance solution by independently learning shape parameter classifiers in marginal eigenspaces in the decreasing order of variation. We evaluated MaShDL for segmenting the lung field from 314 normal and abnormal pediatric chest radiographs and obtained a mean Dice similarity coefficient of 0.927 using only the four highest modes of variation (compared to 0.888 with classical ASM 1 (p-value=0.01) using same configuration). To the best of our knowledge this is the first demonstration of using DL framework for parametrized shape learning for the delineation of deformable objects.

Marginal shape deep learning: applications to pediatric lung field segmentation

NASA Astrophysics Data System (ADS)

Mansoor, Awais; Cerrolaza, Juan J.; Perez, Geovany; Biggs, Elijah; Nino, Gustavo; Linguraru, Marius George

2017-02-01

Representation learning through deep learning (DL) architecture has shown tremendous potential for identification, local- ization, and texture classification in various medical imaging modalities. However, DL applications to segmentation of objects especially to deformable objects are rather limited and mostly restricted to pixel classification. In this work, we propose marginal shape deep learning (MaShDL), a framework that extends the application of DL to deformable shape segmentation by using deep classifiers to estimate the shape parameters. MaShDL combines the strength of statistical shape models with the automated feature learning architecture of DL. Unlike the iterative shape parameters estimation approach of classical shape models that often leads to a local minima, the proposed framework is robust to local minima optimization and illumination changes. Furthermore, since the direct application of DL framework to a multi-parameter estimation problem results in a very high complexity, our framework provides an excellent run-time performance solution by independently learning shape parameter classifiers in marginal eigenspaces in the decreasing order of variation. We evaluated MaShDL for segmenting the lung field from 314 normal and abnormal pediatric chest radiographs and obtained a mean Dice similarity coefficient of 0:927 using only the four highest modes of variation (compared to 0:888 with classical ASM1 (p-value=0:01) using same configuration). To the best of our knowledge this is the first demonstration of using DL framework for parametrized shape learning for the delineation of deformable objects.

Marginal Shape Deep Learning: Applications to Pediatric Lung Field Segmentation

PubMed Central

Mansoor, Awais; Cerrolaza, Juan J.; Perez, Geovanny; Biggs, Elijah; Nino, Gustavo; Linguraru, Marius George

2017-01-01

Representation learning through deep learning (DL) architecture has shown tremendous potential for identification, localization, and texture classification in various medical imaging modalities. However, DL applications to segmentation of objects especially to deformable objects are rather limited and mostly restricted to pixel classification. In this work, we propose marginal shape deep learning (MaShDL), a framework that extends the application of DL to deformable shape segmentation by using deep classifiers to estimate the shape parameters. MaShDL combines the strength of statistical shape models with the automated feature learning architecture of DL. Unlike the iterative shape parameters estimation approach of classical shape models that often leads to a local minima, the proposed framework is robust to local minima optimization and illumination changes. Furthermore, since the direct application of DL framework to a multi-parameter estimation problem results in a very high complexity, our framework provides an excellent run-time performance solution by independently learning shape parameter classifiers in marginal eigenspaces in the decreasing order of variation. We evaluated MaShDL for segmenting the lung field from 314 normal and abnormal pediatric chest radiographs and obtained a mean Dice similarity coefficient of 0.927 using only the four highest modes of variation (compared to 0.888 with classical ASM1 (p-value=0.01) using same configuration). To the best of our knowledge this is the first demonstration of using DL framework for parametrized shape learning for the delineation of deformable objects. PMID:28592911

Source to sink evaluation of sediment routing in the Gulf of Alaska and Southeast Alaska: A thermochronometric perspective

NASA Astrophysics Data System (ADS)

Dunn, Catherine A.; Enkelmann, Eva; Ridgway, Kenneth D.; Allen, Wai K.

2017-03-01

In this study, we present a source to sink evaluation of sediment routing at the glaciated convergent margin in Southeast Alaska. We investigate the efficacy of thermochronology to record spatial and temporal exhumation patterns in synorogenic sediment using Neogene strata drilled by Integrated Ocean Drilling Program Expedition 341 in the Gulf of Alaska. We present 1641 and 529 new detrital zircon and apatite fission track ages, respectively, from strata deposited on the continental shelf, slope, and deep-sea fans. These data are compared to results from the proposed source terrains, including the St. Elias Mountains and new data from the Alsek River. We find that the offshore Bagley-Bering sediment contains grains recording cooling ages much older (80-35 Ma) than those reported from the St. Elias syntaxis (3-2 Ma), indicating that extreme rapid exhumation does not extend west of the Seward-Bagley divide. Data from the sediment on the continental shelf, slope, and proximal deep sea all yield similar results, suggesting the same general source region since 1.2 Ma and limited sediment mixing along this glaciated margin. Data from sediment in the distal deep sea show that extreme, rapid, and deep-seated exhumation was ongoing at 11-8 Ma. Overall, this study demonstrates the strengths and limitations of using detrital fission track thermochronology to understand sediment routing on a glaciated convergent margin and to record changes in exhumation rates over geologic time scales.

Late 20th Century Deep-seated Vertical Motions in New Orleans and implications for Gulf Coast Subsidence

NASA Astrophysics Data System (ADS)

Dokka, R. K.

2010-12-01

Subsidence of the Mississippi River delta and adjoining coastal areas is widely thought to be dominated by compaction of Holocene sediments. Current public policies regarding hurricane protection and ecosystems restoration are founded on this interpretation. To test this hypothesis, monuments that penetrate the entire Holocene section were measured using geodetic leveling and water gauges attached to bridge foundations. Results show that the entire sampling area subsided between 1955 and 1995 in amounts unanticipated by previous models. Subsidence due to processes originating below the Holocene section locally exceeded 0.9 m between 1955 and 1995. The maxima of deep subsidence occurred in the urbanized and industrialized sections of eastern New Orleans. Subsidence decreased away from urbanized areas and north of the belt of active basin margin normal faults; this decrease in subsidence continued to the north and east along the Mississippi coast. These independent measurements provide insights into the complexity and causes of modern landscape change in the region. Modern subsidence is clearly not dominated solely by shallow processes such as natural compaction, Deep subsidence occurring east and north of the basin margin faults can be explained by regional tectonic loading of the lithosphere by the modern Mississippi River delta and local groundwater withdrawal. Sharp, local changes in subsidence coincide with strands of the basin margin normal fault system. Deep subsidence of the New Orleans area can be explained by a combination of groundwater withdrawal from shallow upper Pleistocene aquifers, the aforementioned lithospheric loading, and non-groundwater-related faulting. Subsidence due to groundwater extraction from aquifers ~160 to 200 m deep dominated the urbanized areas from ~1960 to the early 1990s and is likely responsible for lowering flood protection structures and bridges in the area by as much as ~0.8 m.

Patterns of Deep-Sea Genetic Connectivity in the New Zealand Region: Implications for Management of Benthic Ecosystems

PubMed Central

Bors, Eleanor K.; Rowden, Ashley A.; Maas, Elizabeth W.; Clark, Malcolm R.; Shank, Timothy M.

2012-01-01

Patterns of genetic connectivity are increasingly considered in the design of marine protected areas (MPAs) in both shallow and deep water. In the New Zealand Exclusive Economic Zone (EEZ), deep-sea communities at upper bathyal depths (<2000 m) are vulnerable to anthropogenic disturbance from fishing and potential mining operations. Currently, patterns of genetic connectivity among deep-sea populations throughout New Zealand’s EEZ are not well understood. Using the mitochondrial Cytochrome Oxidase I and 16S rRNA genes as genetic markers, this study aimed to elucidate patterns of genetic connectivity among populations of two common benthic invertebrates with contrasting life history strategies. Populations of the squat lobster Munida gracilis and the polychaete Hyalinoecia longibranchiata were sampled from continental slope, seamount, and offshore rise habitats on the Chatham Rise, Hikurangi Margin, and Challenger Plateau. For the polychaete, significant population structure was detected among distinct populations on the Chatham Rise, the Hikurangi Margin, and the Challenger Plateau. Significant genetic differences existed between slope and seamount populations on the Hikurangi Margin, as did evidence of population differentiation between the northeast and southwest parts of the Chatham Rise. In contrast, no significant population structure was detected across the study area for the squat lobster. Patterns of genetic connectivity in Hyalinoecia longibranchiata are likely influenced by a number of factors including current regimes that operate on varying spatial and temporal scales to produce potential barriers to dispersal. The striking difference in population structure between species can be attributed to differences in life history strategies. The results of this study are discussed in the context of existing conservation areas that are intended to manage anthropogenic threats to deep-sea benthic communities in the New Zealand region. PMID:23185341

Resolving the fine-scale velocity structure of continental hyperextension at the Deep Galicia Margin using full-waveform inversion

NASA Astrophysics Data System (ADS)

Davy, R. G.; Morgan, J. V.; Minshull, T. A.; Bayrakci, G.; Bull, J. M.; Klaeschen, D.; Reston, T. J.; Sawyer, D. S.; Lymer, G.; Cresswell, D.

2018-01-01

Continental hyperextension during magma-poor rifting at the Deep Galicia Margin is characterized by a complex pattern of faulting, thin continental fault blocks and the serpentinization, with local exhumation, of mantle peridotites along the S-reflector, interpreted as a detachment surface. In order to understand fully the evolution of these features, it is important to image seismically the structure and to model the velocity structure to the greatest resolution possible. Traveltime tomography models have revealed the long-wavelength velocity structure of this hyperextended domain, but are often insufficient to match accurately the short-wavelength structure observed in reflection seismic imaging. Here, we demonstrate the application of 2-D time-domain acoustic full-waveform inversion (FWI) to deep-water seismic data collected at the Deep Galicia Margin, in order to attain a high-resolution velocity model of continental hyperextension. We have used several quality assurance procedures to assess the velocity model, including comparison of the observed and modeled waveforms, checkerboard tests, testing of parameter and inversion strategy and comparison with the migrated reflection image. Our final model exhibits an increase in the resolution of subsurface velocities, with particular improvement observed in the westernmost continental fault blocks, with a clear rotation of the velocity field to match steeply dipping reflectors. Across the S-reflector, there is a sharpening in the velocity contrast, with lower velocities beneath S indicative of preferential mantle serpentinization. This study supports the hypothesis that normal faulting acts to hydrate the upper-mantle peridotite, observed as a systematic decrease in seismic velocities, consistent with increased serpentinization. Our results confirm the feasibility of applying the FWI method to sparse, deep-water crustal data sets.

Ciliatamides A-C, bioactive lipopeptides from the deep-sea sponge Aaptos ciliata.

PubMed

Nakao, Yoichi; Kawatsu, Shizuka; Okamoto, Chikane; Okamoto, Masaaki; Matsumoto, Yoshitsugu; Matsunaga, Shigeki; van Soest, Rob W M; Fusetani, Nobuhiro

2008-03-01

Three lipopeptides, ciliatamides A-C ( 1- 3), were isolated from the deep-sea sponge Aaptos ciliata, and their structures were elucidated on the basis of spectroscopic and chemical methods. Ciliatamides A ( 1) and B ( 2) were found to be antileishmanial, while 2 also exhibited marginal cytotoxicity to HeLa cells.

Too Deep or Not Too Deep?: A Propensity-Matched Comparison of the Analgesic Effects of a Superficial Versus Deep Serratus Fascial Plane Block for Ambulatory Breast Cancer Surgery.

PubMed

Abdallah, Faraj W; Cil, Tulin; MacLean, David; Madjdpour, Caveh; Escallon, Jaime; Semple, John; Brull, Richard

2018-07-01

Serratus fascial plane block can reduce pain following breast surgery, but the question of whether to inject the local anesthetic superficial or deep to the serratus muscle has not been answered. This cohort study compares the analgesic benefits of superficial versus deep serratus plane blocks in ambulatory breast cancer surgery patients at Women's College Hospital between February 2014 and December 2016. We tested the joint hypothesis that deep serratus block is noninferior to superficial serratus block for postoperative in-hospital (pre-discharge) opioid consumption and pain severity. One hundred sixty-six patients were propensity matched among 2 groups (83/group): superficial and deep serratus blocks. The cohort was used to evaluate the effect of blocks on postoperative oral morphine equivalent consumption and area under the curve for rest pain scores. We considered deep serratus block to be noninferior to superficial serratus block if it were noninferior for both outcomes, within 15 mg morphine and 4 cm·h units margins. Other outcomes included intraoperative fentanyl requirements, time to first analgesic request, recovery room stay, and incidence of postoperative nausea and vomiting. Deep serratus block was associated with postoperative morphine consumption and pain scores area under the curve that were noninferior to those of the superficial serratus block. Intraoperative fentanyl requirements, time to first analgesic request, recovery room stay, and postoperative nausea and vomiting were not different between blocks. The postoperative in-hospital analgesia associated with deep serratus block is as effective (within an acceptable margin) as superficial serratus block following ambulatory breast cancer surgery. These new findings are important to inform both current clinical practices and future prospective studies.

77 FR 62260 - Niles America Wintech, Inc., Warehousing Division, a Valeo Company, Including On-Site Leased...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-12

..., Adecco Employment Services, Winchester, KY; Niles America Wintech, Inc., Assembly and Testing Division, a... former workers of Niles America Wintech, Inc., Warehousing Division and Assembly and Testing Division...

Natural deep eutectic solvents (NADES) as green solvents for carbon dioxide capture

NASA Astrophysics Data System (ADS)

Mulia, Kamarza; Putri, Sylvania; Krisanti, Elsa; Nasruddin

2017-03-01

This study was conducted to determine the effectiveness of Natural Deep Eutectic Solvent (NADES), consisting of choline chloride and a hydrogen bonding donor (HBD) compound, in terms of carbon dioxide absorption. Solubility of carbon dioxide in NADES was found to be influenced HBD compound used and choline chloride to HBD ratio, carbon dioxide pressure, and contact time. HBD and choline/HBD ratios used were 1,2-propanediol (1:2), glycerol (1:2), and malic acid (1:1). The carbon dioxide absorption measurement was conducted using an apparatus that utilizes the volumetric method. Absorption curves were obtained up to pressures of 30 bar, showing a linear relationship between the amount absorbed and the final pressure of carbon dioxide. The choline and 1,2-propanediol eutectic mixture absorbs the highest amount of carbon dioxide, approaching 0.1 mole-fraction at 3.0 MPa and 50°C. We found that NADES ability to absorb carbon dioxide correlates with its polarity as tested using Nile Red as a solvatochromic probe.

Geomorphology and Neogene tectonic evolution of the Palomares continental margin (Western Mediterranean)

NASA Astrophysics Data System (ADS)

Gómez de la Peña, Laura; Gràcia, Eulàlia; Muñoz, Araceli; Acosta, Juan; Gómez-Ballesteros, María; R. Ranero, César; Uchupi, Elazar

2016-10-01

The Palomares continental margin is located in the southeastern part of Spain. The margin main structure was formed during Miocene times, and it is currently part of the wide deformation zone characterizing the region between the Iberian and African plates, where no well-defined plate boundary occurs. The convergence between these two plates is here accommodated by several structures, including the left lateral strike-slip Palomares Fault. The region is characterized by sparse, low to moderate magnitude (Mw < 5.2) shallow instrumental earthquakes, although large historical events have also occurred. To understand the recent tectonic history of the margin we analyze new high-resolution multibeam bathymetry data and re-processed three multichannel seismic reflection profiles crossing the main structures. The analysis of seafloor morphology and associated subsurface structure provides new insights of the active tectonic features of the area. In contrast to other segments of the southeastern Iberian margin, the Palomares margin contains numerous large and comparatively closely spaced canyons with heads that reach near the coast. The margin relief is also characterized by the presence of three prominent igneous submarine ridges that include the Aguilas, Abubacer and Maimonides highs. Erosive processes evidenced by a number of scars, slope failures, gullies and canyon incisions shape the present-day relief of the Palomares margin. Seismic images reveal the deep structure distinguishing between Miocene structures related to the formation of the margin and currently active features, some of which may reactivate inherited structures. The structure of the margin started with an extensional phase accompanied by volcanic accretion during the Serravallian, followed by a compressional pulse that started during the Latemost Tortonian. Nowadays, tectonic activity offshore is subdued and limited to few, minor faults, in comparison with the activity recorded onshore. The deep Algero-Balearic Basin is affected by surficial processes, associated to halokinesis of Messinian evaporites.

The T-Reflection and the Deep Crustal Structure of the Vøring Margin, Offshore mid-Norway

NASA Astrophysics Data System (ADS)

Abdelmalak, M. M.; Faleide, J. I.; Planke, S.; Gernigon, L.; Zastrozhnov, D.; Shephard, G. E.; Myklebust, R.

2017-11-01

Seismic reflection data along volcanic passive margins frequently provide imaging of strong and laterally continuous reflections in the middle and lower crust. We have completed a detailed 2-D seismic interpretation of the deep crustal structure of the Vøring Margin, offshore mid-Norway, where high-quality seismic data allow the identification of high-amplitude reflections, locally referred to as the T-Reflection. Using a dense seismic grid, we have mapped the geometry of the T-Reflection in order to compare it with filtered Bouguer gravity anomalies and seismic refraction data. The T-Reflection is identified between 7 and 10 s. Sometimes it consists of one single smooth reflection. However, it is frequently associated with a set of rough multiple reflections displaying discontinuous segments with varying geometries, amplitudes, and contact relationships. The T-Reflection seems to be connected to deep sill networks and is locally identified at the continuation of basement high structures or terminates over fractures and faults. The T-Reflection presents a low magnetic signal. The spatial correlation between the filtered positive Bouguer gravity anomalies and the deep dome-shaped reflections indicates that the latter represent a high-impedance boundary contrast associated with a high-density and high-velocity body. In 50% of the outer Vøring Margin, the depth of the mapped T-Reflection is found to correspond to the depth of the top of the Lower Crustal Body (LCB), which is characterized by high P wave velocities (>7 km/s). We present a tectonic scenario, where a large part of the deep crustal structure is composed of preserved upper continental crustal blocks and middle to lower crustal lenses of inherited high-grade metamorphic rocks. Deep intrusions into the faulted crustal blocks are responsible for the rough character of the T-Reflection, whereas intrusions into the ductile lower crust and detachment faults are likely responsible for its smoother character. Deep magma intrusions can be responsible for regional metamorphic processes leading to an increasing velocity of the lower crust to more than 7 km/s. The result is a heterogeneous LCB that likely represents a complex mixture of pre- to syn-breakup mafic and ultramafic rocks (cumulates and sills) and old metamorphic rocks such as granulites and eclogites. An increasing degree of melting toward the breakup axis is responsible for an increasing proportion of cumulates and sill intrusions in the lower crust.

The intersection of antiretroviral therapy, peer support programmes, and economic empowerment with HIV stigma among HIV-positive women in West Nile Uganda.

PubMed

Kellett, Nicole Coffey; Gnauck, Katherine

2016-12-01

HIV stigma remains a major problem of the AIDS epidemic in sub-Saharan Africa. Women fear impending social stigma including blame, isolation and abuse. HIV infection and HIV stigma interact cyclically, creating and reinforcing economic and social exclusion for individuals living with HIV. Evidence suggests that interventions for people living with HIV infection that include, in combination, antiretroviral therapy (ART), peer support and economic empowerment are likely to be more effective than if used alone. We report a qualitative study in West Nile Uganda that explored perceptions of HIV stigma among fifty-four HIV-positive women who had similar access to ART and HIV peer support programmes, but varying levels of participation (full-time, intermittent, none) in economic empowerment programmes. Our study found that access to ART, peer support groups, and economic empowerment programmes helped to curb perceptions of deep-seated HIV stigma for participants. More expressions of usefulness, hope and psychological well-being prevailed with participants who had increased participation in economic empowerment programmes. Our findings underscore the value of HIV outreach programmes which combine ART, peer support and economic empowerment to alleviate HIV stigma. Further research to quantify the interaction of these factors is warranted.

Use of an Internal Positive Control in a Multiplex Reverse Transcription-PCR To Detect West Nile Virus RNA in Mosquito Pools

PubMed Central

Eisler, Diane L.; McNabb, Alan; Jorgensen, Danielle R.; Isaac-Renton, Judith L.

2004-01-01

We report on the use of West Nile virus Armored RNA as an internal positive control (IPC) for the extraction and reverse transcription-PCR (RT-PCR) of RNA extracted from field-collected mosquitoes and on a multiplex real-time Taqman RT-PCR to simultaneously detect the 3′ noncoding region of West Nile virus and the West Nile virus NS5-2 region comprising the IPC. Mosquito pools from the province of British Columbia, Canada (n = 635), were tested in duplicate and found to be negative for West Nile virus and positive for the IPC. Known West Nile virus-positive supernatants from mosquito pools from the provinces of Alberta and Manitoba were tested in duplicate and found to be positive for both regions of the West Nile virus genome. The mean cycle threshold (Ct) value for the IPC in batch extraction controls ± 2 standard deviations was found to be 36.43 ± 1.78 cycles. IPCs of 98.4% (624) of West Nile virus-negative pools fell within this range, indicating the reproducibility of RNA extraction and RT-PCR for pools varying in mosquito genus and number. A comparison of mosquito pool genera revealed no significant genus effect on the Ct value of the IPC. The incorporation of West Nile virus Armored RNA as an IPC allows monitoring of RNA extraction and RT-PCR and detection of false-negative results due to failures in these processes or to PCR inhibition, respectively. PMID:14766868

Control Over the Nile: Implications across Nations

DTIC Science & Technology

2010-06-01

states is evident in the 1959 Full Utilization of the Nile Waters Agreement between Egypt and the Sudan. Of the Nile’s annual average water yield of...grain, maize —has been falling. Kenya saw a 22 per cent decrease in 2000 from the 1998 harvest and a 36 per cent decrease from the 1999 harvest—leading...incorporated in a Nile water resource-sharing regime. The potential for Nile basin conflict or cooperation revolves around, first, the gap between water

Potential for adaptive evolution at species range margins: contrasting interactions between red coral populations and their environment in a changing ocean.

PubMed

Ledoux, Jean-Baptiste; Aurelle, Didier; Bensoussan, Nathaniel; Marschal, Christian; Féral, Jean-Pierre; Garrabou, Joaquim

2015-03-01

Studying population-by-environment interactions (PEIs) at species range margins offers the opportunity to characterize the responses of populations facing an extreme regime of selection, as expected due to global change. Nevertheless, the importance of these marginal populations as putative reservoirs of adaptive genetic variation has scarcely been considered in conservation biology. This is particularly true in marine ecosystems for which the deep refugia hypothesis proposes that disturbed shallow and marginal populations of a given species can be replenished by mesophotic ones. This hypothesis therefore assumes that identical PEIs exist between populations, neglecting the potential for adaptation at species range margins. Here, we combine reciprocal transplant and common garden experiments with population genetics analyses to decipher the PEIs in the red coral, Corallium rubrum. Our analyses reveal partially contrasting PEIs between shallow and mesophotic populations separated by approximately one hundred meters, suggesting that red coral populations may potentially be locally adapted to their environment. Based on the effective population size and connectivity analyses, we posit that genetic drift may be more important than gene flow in the adaptation of the red coral. We further investigate how adaptive divergence could impact population viability in the context of warming and demonstrate differential phenotypic buffering capacities against thermal stress. Our study questions the relevance of the deep refugia hypothesis and highlights the conservation value of marginal populations as a putative reservoir of adaptive genetic polymorphism.

Stratigraphy of two conjugate margins (Gulf of Lion and West Sardinia): modeling of vertical movements and sediment budgets

NASA Astrophysics Data System (ADS)

Leroux, Estelle; Gorini, Christian; Aslanian, Daniel; Rabineau, Marina; Blanpied, Christian; Rubino, Jean-Loup; Robin, Cécile; Granjeon, Didier; Taillepierre, Rachel

2016-04-01

The post-rift (~20-0 Ma) vertical movements of the Provence Basin (West Mediterranean) are quantified on its both conjugate (the Gulf of Lion and the West Sardinia) margins. This work is based on the stratigraphic study of sedimentary markers using a large 3D grid of seismic data, correlations with existing drillings and refraction data. The post-rift subsidence is measured by the direct use of sedimentary geometries analysed in 3D [Gorini et al., 2015; Rabineau et al., 2014] and validated by numerical stratigraphic modelling. Three domains were found: on the platform (1) and slope (2), the subsidence takes the form of a seaward tilting with different amplitudes, whereas the deep basin (3) subsides purely vertically [Leroux et al., 2015a]. These domains correspond to the deeper crustal domains respectively highlighted by wide angle seismic data. The continental crust (1) and the thinned continental crust (2) are tilted, whereas the intermediate crust, identified as lower continental exhumed crust [Moulin et al., 2015, Afhilado et al., 2015] (3) sagged. The post-break-up subsidence re-uses the initial hinge lines of the rifting phase. This striking correlation between surface geologic processes and deep earth dynamic processes emphasizes that the sedimentary record and sedimentary markers is a window into deep geodynamic processes and dynamic topography. Pliocene-Pleistocene seismic markers enabled high resolution quantification of sediment budgets over the past 6 Myr [Leroux et al., in press]. Sediment budget history is here completed on the Miocene interval. Thus, the controlling factors (climate, tectonics and eustasy) are discussed. Afilhado, A., Moulin, M., Aslanian, D., Schnürle, P., Klingelhoefer, F., Nouzé, H., Rabineau, M., Leroux, E. & Beslier, M.-O. (2015). Deep crustal structure across a young 1 passive margin from wide-angle and reflection seismic data (The SARDINIA Experiment) - II. Sardinia's margin. Bull. Soc. géol. France, 186, ILP Spec. issue, 4-5, 331-351. Gorini, C., Montadert, L., Rabineau, M., (2015) New imaging of the salinity crisis: Dual Messinian lowstand megasequences recorded in the deep basin of both the eastern and western Mediterranean, Marine and Petroleum Geology (2015), doi: 10.1016/j.marpetgeo.2015.01.009. Leroux, E., Aslanian, D., Rabineau, M., Moulin, M., Granjeon, D., Gorini C. & Droz, L. (2015a). Sedimentary markers in the Provençal basin (Western Mediterranean): a window into deep geodynamic processes. Terra Nova, 27(2), 122-129. Leroux, E., Rabineau, M., Aslanian, D., Gorini, C., Molliex, S., Bache, F., Robin, C., Droz, L., Moulin, M., Poort, J., Rubino, J.-L. & Suc, J.P. (2016, in press). High resolution evolution of terrigenous sediment yields in the Provence Basin during the last 6 Ma: relation with climate and tectonic. Basin Research, xx, xx-xx (ID: 4759575-1545130). Moulin, M., Klingelhoefer, F., Afiladho, A., Aslanian, D., Schnürle, P., Nouze, H., Beslier, M.-O. & Feld, A. (2015). Deep crustal structure across an young passive margin from wide-angle and reflection seismic data (The SARDINIA Experiment) - I. Gulf of Lion's margin, Bull. Soc. géol. France., 186, ILP Spec. issue, 4-5,309-330. Rabineau, M., Leroux, E., Aslanian, D., Bache, F., Gorini, C., Moulin, M., Molliex, S., Droz, L., Reis, T. D., Rubino, J.-L., Guillocheau, F. & Olivet, J.-L. (2014). Quantifying subsidence and isostatic readjustment using sedimentary markers (example in the Gulf of Lion). Earth and Planetary Science Letters, 388, 1-14.

Assessment of undiscovered petroleum resources of the Amerasia Basin Petroleum Province

USGS Publications Warehouse

Houseknecht, David W.; Bird, Kenneth J.; Garrity, Christopher P.

2012-01-01

The Amerasia Basin Petroleum Province encompasses the Canada Basin and the sediment prisms along the Alaska and Canada margins, outboard from basinward margins (hingelines) of the rift shoulders that formed during extensional opening of the Canada Basin. The province includes the Mackenzie delta and slope, the outer shelves and marine slopes along the Arctic margins of Alaska and Canada, and the deep Canada Basin. The province is divided into four assessment units (AUs): (1) The Canning-Mackenzie deformed margin AU is that part of the rifted margin where the Brooks Range orogenic belt has overridden the rift shoulder and is deforming the rifted-margin prism of sediment outboard of the hingeline. This is the only part of the Amerasia Basin Province that has been explored and—even though more than 3 billion barrels of oil equivalent (BBOE) of oil, gas, and condensate have been discovered—none has been commercially produced. (2) The Alaska passive margin AU is the rifted-margin prism of sediment lying beneath the Beaufort outer shelf and slope that has not been deformed by tectonism. (3) The Canada passive margin AU is the rifted-margin prism of sediment lying beneath the Arctic outer shelf and slope (also known as the polar margin) of Canada that has not been deformed by tectonism. (4) The Canada Basin AU includes the sediment wedge that lies beneath the deep Canada Basin, north of the marine slope developed along the Alaska and Canada margins. Mean estimates of risked, undiscovered, technically recoverable resources include more than 6 billion barrels of oil (BBO), more than 19 trillion cubic feet (TCF) of associated gas, and more than 16 TCF of nonassociated gas in the Canning-Mackenzie deformed margin AU; about 1 BBO, about 3 TCF of associated gas, and about 3 TCF of nonassociated gas in the Alaska passive margin AU; and more than 2 BBO, about 7 TCF of associated gas, and about 8 TCF of nonassociated gas in the Canada passive margin AU. Quantities of natural gas liquids also are assessed in each AU. The Canada Basin AU was not quantitatively assessed because it is judged to hold less than 10 percent probability of containing at least one accumulation of 50 million barrels of oil equivalent.

A Multi-Proxy Approach to Reconstruct Climate Variability in the Western Mediterranean across the Penultimate and Last Glacial Period

NASA Astrophysics Data System (ADS)

Dixit, Y.; Toucanne, S.; Bonnin, L.; Fontanier, C.; Jouet, G.; Tripati, A. K.

2016-12-01

The Mediterranean as a model miniature ocean is an ideal study area for the links between climate change and anoxia. Organic rich-sapropelic deposits punctuate Quaternary sediments series in the basin. These deposits reveal the occurrence of anoxic conditions during times when the circulation of the Mediterranean ocean was deeply perturbed. The `'Nilotic paradigm' proposes anoxia was a direct result of massive inputs of fresh water from the Nile. It is also possible that these sapropels could occur in response to periods of intense rainfall and riverine discharge on the northern Mediterranean coast. To resolve the sequence of events linked to sapropel deposition in the western Mediterranean, we use a multi-proxy (oxygen and carbon isotopes, benthic foraminifera assemblage and trace element geochemistry of foraminifera calcite) approach to examine sediments from the Tyrhennian Sea off the eastern Corsica margin in order to reconstruct climate variability during the penultimate glacial termination, and we compare results to those for the last glacial period. Our preliminary results show increased abundance of epifaunal and deep infaunal benthic species during MIS 5e ( 122-125 kyr BP), accompanied by a rise in Mg/Ca-based sea surface temperature (SST) using G. bulloides. A sharp decline in SST at 135 kyr BP coincides with Heinrich Stadial 5 in the North Atlantic. We will compare the timing of Mg/Ca-based SST minima and reconstructed water d18O variations to Heinrich Stadials in the North Atlantic in order to infer the mechanisms responsible for cooling in the Tyrrhenian Sea. This analysis should shed light on the proposed atmospheric teleconnection causing cooling of western Mediterranean waters via intensification of the Northern Hemisphere high-latitude wind systems.

Molecular phylogeny of osteoglossoids: a new model for Gondwanian origin and plate tectonic transportation of the Asian arowana.

PubMed

Kumazawa, Y; Nishida, M

2000-12-01

One of the traditional enigmas in freshwater zoogeography has been the evolutionary origin of Scleropages formosus inhabiting Southeast Asia (the Asian arowana), which is a species threatened with extinction among the highly freshwater-adapted fishes from the order Osteoglossiformes. Dispersalists have hypothesized that it originated from the recent (the Miocene or later) transmarine dispersal of morphologically quite similar Australasian arowanas across Wallace's Line, but this hypothesis has been questioned due to their remarkable adaptation to freshwater. We determined the complete nucleotide sequences of two mitochondrial protein genes from 12 osteoglossiform species, including all members of the suborder Osteoglossoidei, with which robust molecular phylogeny was constructed and divergence times were estimated. In agreement with previous morphology-based phylogenetic studies, our molecular phylogeny suggested that the osteoglossiforms diverged from a basal position of the teleostean lineage, that heterotidines (the Nile arowana and the pirarucu) form a sister group of osteoglossines (arowanas in South America, Australasia, and Southeast Asia), and that the Asian arowana is more closely related to Australasian arowanas than to South American ones. However, molecular distances between the Asian and Australasian arowanas were much larger than expected from the fact that they are classified within the same genus. By using the molecular clock of bony fishes, tested for its good performance for rather deep divergences and calibrated using some reasonable assumptions, the divergence between the Asian and Australasian arowanas was estimated to date back to the early Cretaceous. Based on the molecular and geological evidence, we propose a new model whereby the Asian arowana vicariantly diverged from the Australasian arowanas in the eastern margin of Gondwanaland and migrated into Eurasia on the Indian subcontinent or smaller continental blocks. This study also implicates the relatively long absence of osteoglossiform fossil records from the Mesozoic.

Hydroclimate variability in the Nile River Basin during the past 28,000 years

NASA Astrophysics Data System (ADS)

Castañeda, Isla S.; Schouten, Stefan; Pätzold, Jürgen; Lucassen, Friedrich; Kasemann, Simone; Kuhlmann, Holger; Schefuß, Enno

2016-03-01

It has long been known that extreme changes in North African hydroclimate occurred during the late Pleistocene yet many discrepancies exist between sites regarding the timing, duration and abruptness of events such as Heinrich Stadial (HS) 1 and the African Humid Period (AHP). The hydroclimate history of the Nile River is of particular interest due to its lengthy human occupation history yet there are presently few continuous archives from the Nile River corridor, and pre-Holocene studies are rare. Here we present new organic and inorganic geochemical records of Nile Basin hydroclimate from an eastern Mediterranean (EM) Sea sediment core spanning the past 28 ka BP. Our multi-proxy records reflect the fluctuating inputs of Blue Nile versus White Nile material to the EM Sea in response to gradual changes in local insolation and also capture abrupt hydroclimate events driven by remote climate forcings, such as HS1. We find strong evidence for extreme aridity within the Nile Basin evolving in two distinct phases during HS1, from 17.5 to 16 ka BP and from 16 to 14.5 ka BP, whereas peak wet conditions during the AHP are observed from 9 to 7 ka BP. We find that zonal movements of the Congo Air Boundary (CAB), and associated shifts in the dominant moisture source (Atlantic versus Indian Ocean moisture) to the Nile Basin, likely contributed to abrupt hydroclimate variability in northern East Africa during HS1 and the AHP as well as to non-linear behavior of hydroclimate proxies. We note that different proxies show variable gradual and abrupt responses to individual hydroclimate events, and thus might have different inherent sensitivities, which may be a factor contributing to the controversy surrounding the abruptness of past events such as the AHP. During the Late Pleistocene the Nile Basin experienced extreme hydroclimate fluctuations, which presumably impacted Paleolithic cultures residing along the Nile corridor.

STS-56 Earth observation of the northeastern Nile Delta

NASA Image and Video Library

1993-04-17

STS-56 Earth observation of the northeastern Nile Delta was photographed from the Earth-orbiting Discovery, Orbiter Vehicle (OV) 103. The branch of the Nile featured in the frame is Daimietta. The Suez Canal marks the boundary of the Nile Delta agriculture and the Sinai Desert to the right. Lake Masada, the dark waterlogged area to the west (left) of Port Said is becoming more saline as the Aswan Dam has reduced sediment downstream. This sediment reduction, according to NASA scientists studying the STS-56 photography, has resulted in increased coastal erosion and the intrusion of a salt-water lens to the ground water, particularly in the northeastern portions of the delta. Center pivot irrigation fields are located along either side of the Ramses Canal, which connects the Daimietta Nile with Great Bitter Lake. This canal has been re-dug three or four times in the past 3,000 years. Historians note that the canal's most famous use was as the departure point of the fleet of Pharaoh Necho. The fleet circumnavigated Africa clockwise from the head of the Red Sea to the Mediterranean coast of the Nile (probably the Rosetta Nile) in a three-year voyage circa 660 BC.

Marginal Space Deep Learning: Efficient Architecture for Volumetric Image Parsing.

PubMed

Ghesu, Florin C; Krubasik, Edward; Georgescu, Bogdan; Singh, Vivek; Yefeng Zheng; Hornegger, Joachim; Comaniciu, Dorin

2016-05-01

Robust and fast solutions for anatomical object detection and segmentation support the entire clinical workflow from diagnosis, patient stratification, therapy planning, intervention and follow-up. Current state-of-the-art techniques for parsing volumetric medical image data are typically based on machine learning methods that exploit large annotated image databases. Two main challenges need to be addressed, these are the efficiency in scanning high-dimensional parametric spaces and the need for representative image features which require significant efforts of manual engineering. We propose a pipeline for object detection and segmentation in the context of volumetric image parsing, solving a two-step learning problem: anatomical pose estimation and boundary delineation. For this task we introduce Marginal Space Deep Learning (MSDL), a novel framework exploiting both the strengths of efficient object parametrization in hierarchical marginal spaces and the automated feature design of Deep Learning (DL) network architectures. In the 3D context, the application of deep learning systems is limited by the very high complexity of the parametrization. More specifically 9 parameters are necessary to describe a restricted affine transformation in 3D, resulting in a prohibitive amount of billions of scanning hypotheses. The mechanism of marginal space learning provides excellent run-time performance by learning classifiers in clustered, high-probability regions in spaces of gradually increasing dimensionality. To further increase computational efficiency and robustness, in our system we learn sparse adaptive data sampling patterns that automatically capture the structure of the input. Given the object localization, we propose a DL-based active shape model to estimate the non-rigid object boundary. Experimental results are presented on the aortic valve in ultrasound using an extensive dataset of 2891 volumes from 869 patients, showing significant improvements of up to 45.2% over the state-of-the-art. To our knowledge, this is the first successful demonstration of the DL potential to detection and segmentation in full 3D data with parametrized representations.

Trace fossil analysis of lacustrine facies and basins

USGS Publications Warehouse

Buatois, L.A.; Mangano, M.G.

1998-01-01

Two ichnofacies are typical of lacustrine depositional systems. The Scoyenia ichnofacies characterizes transitional terrestrial/nonmarine aquatic substrates, periodically inundated or desiccated, and therefore is commonly present in lake margin facies. The Mermia ichnofacies is associated with well oxygenated, permanent subaqueous, fine-grained substrates of hydrologically open, perennial lakes. Bathymetric zonations within the Mermia ichnofacies are complicated by the wide variability of lacustrine systems. Detected proximal-distal trends are useful within particular lake basins, but commonly difficult to extrapolate to other lakes. Other potential ichnofacies include the typically marine Skolithos ichnofacies for high-energy zones of lakes and substrate-controlled, still unnamed ichnofacies, associated to lake margin deposits. Trace fossils are useful for sedimentologic analysis of event beds. Lacustrine turbidites are characterized by low-diversity suites, reflecting colonization by opportunistic organisms after the turbidite event. Underflow current beds record animal activity contemporaneous with nearly continuous sedimentation. Ichnologic studies may also help to distinguish between marine and lacustrine turbidites. Deep-marine turbidites host the Nereites ichnofacies that consists of high diversity of ornate grazing traces and graphoglyptids, recording highly specialized feeding strategies developed to solve the problem of the scarcity of food in the deep sea. Deep lacustrine environments contain the Mermia ichnofacies, which is dominated by unspecialized grazing and feeding traces probably related to the abundance and accessibility of food in lacustrine systems. The lower diversity of lacustrine ichnofaunas in comparison with deep-sea assemblages more likely reflects lower species diversity as a consequence of less stable conditions. Increase of depth and extent of bioturbation through geologic time produced a clear signature in the ichnofabric record of lacustrine facies. Paleozoic lacustrine ichnofaunas are typically dominated by surface trails with little associated bioturbation. During the Mesozoic, bioturbation depth was higher in lake margin facies than in fully lacustrine deposits. While significant degrees of bioturbation were attained in lake margin facies during the Triassic, major biogenic disruption of primary bedding in subaqueous lacustrine deposits did not occur until the Cretaceous.

Enhanced emission of Nile Red on plasmonic platforms

NASA Astrophysics Data System (ADS)

Synak, Anna; Bojarski, Piotr; Grobelna, Beata; Gryczyński, Ignacy; Fudala, Rafał; Mońka, Michal

2018-04-01

Strongly enhanced fluorescence of Nile Red deposited in the vicinity of silver nanoparticles and gold semitransparent mirror was observed. The properties of three different plasmonic platforms based on TiO2, TiO2-GLYMO (1:1) and SiO2 matrices were studied with spectroscopic and microscopic techniques. Significant differences of Nile Red spectroscopic properties in both matrices were observed. In particular, the sensitivity of Nile Red fluorescence enhancement and its peak location to the polarity of local surrounding was found.

Chronobiology of deep-water decapod crustaceans on continental margins.

PubMed

Aguzzi, Jacopo; Company, Joan B

2010-01-01

Species have evolved biological rhythms in behaviour and physiology with a 24-h periodicity in order to increase their fitness, anticipating the onset of unfavourable habitat conditions. In marine organisms inhabiting deep-water continental margins (i.e. the submerged outer edges of continents), day-night activity rhythms are often referred to in three ways: vertical water column migrations (i.e. pelagic), horizontal displacements within benthic boundary layer of the continental margin, along bathymetric gradients (i.e. nektobenthic), and endobenthic movements (i.e. rhythmic emergence from the substrate). Many studies have been conducted on crustacean decapods that migrate vertically in the water column, but much less information is available for other endobenthic and nektobenthic species. Also, the types of displacement and major life habits of most marine species are still largely unknown, especially in deep-water continental margins, where steep clines in habitat factors (i.e. light intensity and its spectral quality, sediment characteristics, and hydrography) take place. This is the result of technical difficulties in performing temporally scheduled sampling and laboratory testing on living specimens. According to this scenario, there are several major issues that still need extensive research in deep-water crustacean decapods. First, the regulation of their behaviour and physiology by a biological clock is almost unknown compared to data for coastal species that are easily accessible to direct observation and sampling. Second, biological rhythms may change at different life stages (i.e. size-related variations) or at different moments of the reproductive cycle (e.g. at egg-bearing) based on different intra- and interspecific interactions. Third, there is still a major lack of knowledge on the links that exist among the observed bathymetric distributions of species and selected autoecological traits that are controlled by their biological clock, such as the diel rhythm of behaviour. Species evolved in a photically variable environment where intra- and inter-specific interactions change along with the community structure over 24 h. Accordingly, the regulation of their biology through a biological clock may be the major evolutionary constraint that is responsible for their reported bathymetric distributions. In this review, our aim is to propose a series of innovative guidelines for a discussion of the modulation of behavioural rhythms of adult decapod crustaceans, focusing on the deep waters of the continental margin areas of the Mediterranean as a paradigm for other marine zones of the world. Copyright © 2010 Elsevier Ltd. All rights reserved.

Microbes of deep marine sediments as viewed by metagenomics

NASA Astrophysics Data System (ADS)

Biddle, J.

2015-12-01

Ten years after the first deep marine sediment metagenome was produced, questions still exist about the nucleic acid sequences we have retrieved. Current data sets, including the Peru Margin, Costa Rica Margin and Iberian Margin show that consistently, data forms larger assemblies at depth due to the reduced complexity of the microbial community. But are these organisms active or preserved? At SMTZs, a change in the assembly statistics is noted, as well as an increase in cell counts, suggesting that cells are truly active. As depth increases, genome sizes are consistently large, suggesting that much like soil microbes, sedimentary microbes may maintain a larger reportorie of genomic potential. Functional changes are seen with depth, but at many sites are not correlated to specific geochemistries. Individual genomes show changes with depth, which raises interesting questions on how the subsurface is settled and maintained. The subsurface does have a distinct genomic signature, including unusual microbial groups, which we are now able to analyze for total genomic content.

Africa's Megafans and Their Tectonic Setting

NASA Technical Reports Server (NTRS)

Wilkinson, M. J.; Burke, K.

2016-01-01

Megafans are a really extensive continental sediment bodies, fluvially derived, and fan-shaped in planform. Only those >80 km long were included in this study. Africa's megafans were mapped for purposes of both comprehensive geomorphic description and as a method of mapping by remote sensing large probable fluvial sediment bodies (we exclude sediment bodies deposited in well defined, modern floodplains and coastal deltas). Our criteria included a length dimension of >80 km and maximum width >40 km, partial cone morphology, and a radial drainage pattern. Visible and especially IR imagery were used to identify the features, combined with topographic SRTM data. We identified 99 megafans most of which are unstudied thus far. Their feeder rivers responsible for depositing megafan sediments rise on, and are consequent drainages oriented down the slopes of the swells that have dominated African landscapes since approximately 34 Ma (the high points in Africa's so-called basin-and-swell topography [1]). Most megafans (66%) have developed along these consequent rivers relatively near the swell cores, oriented radially away from the swells. The vast basins between the swells provide accommodation for megafan sediment wedges. Although clearly visible remotely, most megafans are inactive as a result of incision by the feeder river (which then no longer operates on the fan surface). Two tectonic settings control the location of Africa's megafans, 66% on swell flanks, and 33% related to rifts. (i) Swell flanks Most megafans are apexed relatively near the core of the parent swell, and are often clustered in groups: e.g., six on the west and north flanks of the Hoggar Swell (Algeria), seven on the north and south flanks of the Tibesti Swell (Libya-Chad borderlands), twelve on the west flank of the Ethiopian Swell, four on the east flank of the East African Swell (Kenya), Africa's largest, and eight around Angola's Bié Swell (western Zambia, northern Namibia). A cluster of possible fans lies on the western margin of the Congo Basin (Mayombe Swell), and on the coastal slopes of the Namibia Swell. Sheer size may have militated aginst the recognition of many megafans: the largest in the Sahara are the Teghahart (378 km, Hoggar Swell, Algeria), and the Wadi Albalata (340 km, Uweinat Swell, Egypt). In southern Africa the largest are the Cubango (320 km, Bié Swell, Angola/ Namibia), and the Limpopo (230 km, Mozambique). (ii) Rift zones (a) Steer's horns basins-wide depressions centered on rifts. The largest contiguous group (n=14) developed in a steer's-horns basin occupies the wide Muglad depression (200-350 km, South Sudan). Four rift-related megafans lie SE of Lake Chad (Chad). Nine megafans occupy the complex Anza Rift in Kenya/South Somalia. The Salamat megafan (Chad), is unusual because it oriented parallel with the linked Salamat, Doseo and Doba rift axes, and is consequently one of the longest in Africa (465 km). (b) Rift depressions sensu stricto. Most rifts are too narrow to provide a transverse dimension large enough to accommodate megafans. Although well-known, the Okavango Rift (NW Botswana, NE Namibia) is unique in Africa in hosting three megafans within identifiable faulted margins. The Nile megafan is Africa's largest (476 km) and comprises the vast Sudd wetland (South Sudan). An explanation for its remarkable size may be its location in a depression at the junction of two conducive tectonic zones, the East African Swell margin and the Muglad steer's-horns depression. Discharge of the River Nile, the largest in the region, has allowed the Nile megafan to outcompete neighboring megafans for space.

The natural history of West Nile virus infection presenting with West Nile virus meningoencephalitis in a man with a prolonged illness: a case report.

PubMed

Mainali, Shraddha; Afshani, Mansoor; Wood, James B; Levin, Michael C

2011-05-25

Estimates indicate that West Nile virus infects approximately one and a half million people in the United States of America. Up to 1% may develop West Nile virus neuroinvasive disease, in which infected patients develop any combination of meningitis, encephalitis, or acute paralysis. A 56-year-old African-American man presented to our hospital with headache, restlessness, fever, myalgias, decreased appetite, and progressive confusion. A cerebrospinal fluid examination showed mild leukocytosis and an elevated protein level. Testing for routine infections was negative. Brain T2-weighted magnetic resonance imaging scans showed marked enlargement of caudate nuclei and increased intensity within the basal ganglia and thalami. A West Nile virus titer was positive, and serial brain magnetic resonance imaging scans showed resolving abnormalities that paralleled his neurological examination. This report is unusual as it portrays the natural history and long-term consequences of West Nile virus meningoencephalitis diagnosed on the basis of serial brain images.

Tectonic types of marginal and inner seas; their place in the development of the crust

NASA Astrophysics Data System (ADS)

Khain, V. E.; Levin, L. E.

1980-12-01

Inner and marginal deep seas are of considerable interest not only for their genesis but also as "micromodels" of oceans. In the latter case it must be noted that some of them essentially differ from oceans in several parameters. They have a shorter period of development, thicker sedimentary cover, less distinct linear magnetic anomalies or an absence of them, high heat-flow values and seismic activity over their whole area. Consequently, the analogy with the oceans has certain limitations as the deep structure of such seas is not homogeneous and they probably vary in genesis. Only a few marginal seas are cut off from the principal areas of the oceans by island arcs formed, most probably, along transform faults. The origin of this type is more or less reliably demonstrated for the Bering Sea. Other types of marginal seas are more numerous. Some of them (such as the Gulf of Aden and the Gulf of California) are embryonic apophyses connected with the oceans. Others are atrophied (the Tasman and the Labrador seas) small oceans. The group of marginal and inner seas which lie in the inside zone of mature or young island arcs is even more numerous. Only a few basins of this group resulted from linear spreading imprinted in the system of magnetic anomalies (the Shikoku-Parese-Vela basin), the rest are supposed to have been formed in the process of diffusal or polyaxial spreading of recent time as in Afar. The majority of inner and marginal seas are younger than recent oceans. They are formed by rifting, oriented crosswise to continental margins of the Atlantic type or along the strike of margins of Andean type. More ancient basins of marginal and inner seas have been involved in Phanerozoic orogens or more rarely became parts of platforms (Ciscaspian syneclise).

Precessional control of Sr ratios in marginal basins during the Messinian Salinity Crisis?

NASA Astrophysics Data System (ADS)

Topper, R. P. M.; Lugli, S.; Manzi, V.; Roveri, M.; Meijer, P. Th.

2014-05-01

Based on 87Sr/86Sr data of the Primary Lower Gypsum (PLG) deposits in the Vena del Gesso basin—a marginal basin of the Mediterranean during the Messinian Salinity Crisis—a correlation between 87Sr/86Sr values and precessional forcing has recently been proposed but not yet confirmed. In this study, a box model is set up to represent the Miocene Mediterranean deep basin and a connected marginal basin. Measurements of 87Sr/86Sr in the Vena del Gesso and estimated salinity extrema are used to constrain model results. In an extensive analysis with this model, we assess whether coeval 87Sr/86Sr and salinity fluctuations could have been forced by precession-driven changes in the fresh water budget. A comprehensive set of the controlling parameters is examined to assess the conditions under which precession-driven 87Sr/86Sr variations occur and to determine the most likely setting for PLG formation. Model results show that precession-driven 87Sr/86Sr and salinity fluctuations in marginal basins are produced in settings within a large range of marginal basin sizes, riverine strontium characteristics, amplitudes of precessional fresh water budget variation, and average fresh water budgets of both the marginal and deep basin. PLG deposition most likely occurred when the Atlantic-Mediterranean connection was restricted, and the average fresh water budget in the Mediterranean was significantly less negative than at present day. Considering the large range of settings in which salinities and 87Sr/86Sr fluctuate on a precessional timescale, 87Sr/86Sr variations are expected to be a common feature in PLG deposits in marginal basins of the Mediterranean.

Analysis of DGGE profiles to explore the relationship between prokaryotic community composition and biogeochemical processes in deep subseafloor sediments from the Peru Margin.

PubMed

Fry, John C; Webster, Gordon; Cragg, Barry A; Weightman, Andrew J; Parkes, R John

2006-10-01

The aim of this work was to relate depth profiles of prokaryotic community composition with geochemical processes in the deep subseafloor biosphere at two shallow-water sites on the Peru Margin in the Pacific Ocean (ODP Leg 201, sites 1228 and 1229). Principal component analysis of denaturing gradient gel electrophoresis banding patterns of deep-sediment Bacteria, Archaea, Euryarchaeota and the novel candidate division JS1, followed by multiple regression, showed strong relationships with prokaryotic activity and geochemistry (R(2)=55-100%). Further correlation analysis, at one site, between the principal components from the community composition profiles for Bacteria and 12 other variables quantitatively confirmed their relationship with activity and geochemistry, which had previously only been implied. Comparison with previously published cell counts enumerated by fluorescent in situ hybridization with rRNA-targeted probes confirmed that these denaturing gradient gel electrophoresis profiles described an active prokaryotic community.

Identification and expression profiles of multiple genes in Nile tilapia in response to bacterial infections

USDA-ARS?s Scientific Manuscript database

To understand the molecular mechanisms involved in response of Nile tilapia (Oreochromis niloticus) to bacterial infection, suppression subtractive cDNA hybridization technique was used to identify upregulated genes in the posterior kidney of Nile tilapia at 6h post infection with Aeromonas hydrophi...

Reactivation West Nile virus infection-related chorioretinitis.

PubMed

Beardsley, Robert; McCannel, Colin

2012-01-01

West Nile Virus is a relatively uncommon infection that can involve retinal and choroidal inflammation leading to photopsias, photophobia, and orbital pain. The diagnosis is made by clinical history, serology, and characteristic funduscopic exam and fluorescein angiography findings. Treatment involves primarily supportive care as there are no known effective anti-viral agents. Visual recovery is usually full. Here we present a case of West Nile Virus Infection Related chorioretinitis that demonstrated active linear chorioretinal lesions approximately one year after the initial infection was diagnosed and treated. The patient noted new onset blurry vision and floaters for two weeks prior to presentation. Antibody titers to West Nile Virus increased from baseline levels indicating active infection. This represents the first case of reactivation West Nile Virus Infection Related chorioretinitis that has been documented.

2D ratiometric fluorescent pH sensor for tracking of cells proliferation and metabolism.

PubMed

Ma, Jun; Ding, Changqin; Zhou, Jie; Tian, Yang

2015-08-15

Extracellular pH plays a vital role no matter in physiological or pathological studies. In this work, a hydrogel, CD@Nile-FITC@Gel (Gel sensor), entrapping the ratiometric fluorescent probe CD@Nile-FITC was developed. The Gel sensor was successfully used for real-time extracellular pH monitoring. In the case of CD@Nile-FITC, pH-sensitive fluorescent dye fluorescein isothiocyanate (FITC) was chosen as the response signal for H(+) and Nile blue chloride (Nile) as the reference signal. The developed fluorescent probe exhibited high selectivity for pH over other metal ions and amino acids. Meanwhile, the carbon-dots-based inorganic-organic probe demonstrated excellent photostability against long-term light illumination. In order to study the extracellular pH change in processes of cell proliferation and metabolism, CD@Nile-FITC probe was entrapped in sodium alginate gel and consequently formed CD@Nile-FITC@Gel. The MTT assay showed low cytotoxicity of the Gel and the pH titration indicated that it could monitor the pH fluctuations linearly and rapidly within the pH range of 6.0-9.0, which is valuable for physiological pH determination. As expected, the real-time bioimaging of the probe was successfully achieved. Copyright © 2015 Elsevier B.V. All rights reserved.

West Nile virus: North American experience

USGS Publications Warehouse

Hofmeister, Erik K.

2011-01-01

West Nile virus, a mosquito-vectored flavivirus of the Japanese encephalitis serogroup, was first detected in North America following an epizootic in the New York City area in 1999. In the intervening 11 years since the arrival of the virus in North America, it has crossed the contiguous USA, entered the Canadian provinces bordering the USA, and has been reported in the Caribbean islands, Mexico, Central America and, more recently, South America. West Nile virus has been reported in over 300 species of birds in the USA and has caused the deaths of thousands of birds, local population declines of some avian species, the clinical illness and deaths of thousands of domestic horses, and the clinical disease in over 30 000 Americans and the deaths of over 1000. Prior to the emergence of West Nile virus in North America, St. Louis encephalitis virus and Dengue virus were the only other known mosquito-transmitted flaviviruses in North America capable of causing human disease. This review will discuss the North American experience with mosquito-borne flavivirus prior to the arrival of West Nile virus, the entry and spread of West Nile virus in North America, effects on wild bird populations, genetic changes in the virus, and the current state of West Nile virus transmission.

Seasonal extension of the Nile River plume into the Mediterranean Sea measured by its optical properties from satellite products

NASA Astrophysics Data System (ADS)

El-Mezayen, M. M.; Rueda-Roa, D. T.; Muller-Karger, F. E.; Otis, D. B.

2016-12-01

The Eastern Mediterranean is a semi-enclosed sea, considered oligotrophic except for the Levantine basin (LB) (30°-38° N, 28°-36° E) where the Nile River plays an important role in its water budget and biogeochemical properties. We studied the seasonality of the Nile River plume using ocean color satellite imagery. We analyzed 1 km resolution satellite chlorophyll-a (Chl-a) and Colored Dissolved Organic Matter (CDOM) concentration estimates from the Moderate Resolution Imaging Spectroradiometer (MODIS, 2002-2015). We used a threshold of 0.2 mg m-3 of Chl-a and 0.03 m-1 of CDOM as a proxy to mask out and calculate the extension of the Nile plume. The plume was always constrained to the coastal region of SE Mediterranean Sea over the 13-year period examined. The annual average surface area of the Nile plume estimated with Chl-a and CDOM was similar (26,245 and 21,195 Km2, respectively). The minimum Nile plume area occurred between April and December (21,329 and 19,177 Km2, for Chl-a and CDOM respectively). Maximum area extension was observed between January-March for both Chl-a and CDOM (40,993 and 27,251 Km2, respectively). There was a conspicuous difference in the maximum surface area of the Nile plume measured with the Chl-a product during February (54,053 Km2) relative to the CDOM proxy (30,749 Km2). During January-March the area of the Nile discharge measured with Chl-a was 1.3-1.8 larger than with the CDOM product, while they were similar the rest of the year. Correlation between Chl-a and CDOM results was high during April-December (R2=0.93, n=122, p<0.001) but somewhat low during January-March (R2=0.65, n=39, p<0.001). This indicates that there is a larger phytoplankton bloom during January-March, due to higher nutrient discharge by Nile water. Both satellite proxies are good indicators of the extent of the Nile plume. We will present further research on the seasonal extension of the Nile plume along the coast and in the LB.

New insights into hydrologic sources and sinks in the Nile Basin: A multi-source satellite data analysis

NASA Astrophysics Data System (ADS)

Senay, G. B.; Velpuri, N. M.; Bohms, S.; Demissie, Y.; Gebremichael, M.

2014-12-01

The Nile River is the longest in the world with a length of 6,800 km. However, the contrast between the length of the river or the size of the basin and the comparatively small volume of basin runoff generated is a unique feature of the Nile Basin. Due to non-availability of in-situ hydrologic data, we do not clearly understand the spatial distribution of hydrologic sources and sinks and how much they control input-output dynamics? In this study, we integrated satellite-derived precipitation, and modeled evapotranspiration data (2000-2012) to describe spatial variability of hydrologic sources and sinks in the Nile Basin. We also used long-term gridded runoff and river discharge data (1869-1984) to understand the discrepancy in the observed and expected flow along the Nile River. Results indicate that over 2000-2012 period, 4 out of 11 countries (Ethiopia, Tanzania, Kenya, and Uganda) in the Nile basin showed a positive water balance while three downstream countries (South Sudan, Sudan, and Egypt) showed a negative balance. The top three countries that contribute most to the flow are Ethiopia, Tanzania and Kenya. The study revealed that ~85% of the runoff generated in the Equatorial region is lost in an inter-station basin that includes the Sudd wetlands in South Sudan; this proportion is higher than the reported loss of 50% at the Sudd wetlands alone. The loss in runoff and flow volume at different sections of the river tend to be more than what can be explained by evaporation losses, suggesting a potential recharge to deeper aquifers that are not connected to the Nile channel systems. On the other hand, we also found that the expected average annual Nile flow at Aswan is larger (97 km3) than the reported amount (84 km3). Gravity Recovery and Climate Experiment (GRACE) mass deviation in storage data analysis showed that at annual time-scales, the Nile Basin shows storage change is substantial while over longer-time periods, it is minimal (<1% of basin precipitation). Due to the large variations of the reported Nile flow at different locations and time periods, the study recommends increased hydro-meteorological instrumentation of the basin. This study improves our understanding of the spatial dynamics of water sources and sinks in the Nile basin and identified emerging hydrologic questions that require further attention.

Extreme Longevity in Proteinaceous Deep-Sea Corals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roark, E B; Guilderson, T P; Dunbar, R B

2009-02-09

Deep-sea corals are found on hard substrates on seamounts and continental margins world-wide at depths of 300 to {approx}3000 meters. Deep-sea coral communities are hotspots of deep ocean biomass and biodiversity, providing critical habitat for fish and invertebrates. Newly applied radiocarbon age date from the deep water proteinaceous corals Gerardia sp. and Leiopathes glaberrima show that radial growth rates are as low as 4 to 35 {micro}m yr{sup -1} and that individual colony longevities are on the order of thousands of years. The management and conservation of deep sea coral communities is challenged by their commercial harvest for the jewelrymore » trade and damage caused by deep water fishing practices. In light of their unusual longevity, a better understanding of deep sea coral ecology and their interrelationships with associated benthic communities is needed to inform coherent international conservation strategies for these important deep-sea ecosystems.« less

Environmental Conditions Outweigh Geographical Contiguity in Determining the Similarity of nifH-Harboring Microbial Communities in Sediments of Two Disconnected Marginal Seas

PubMed Central

Zhou, Haixia; Dang, Hongyue; Klotz, Martin G.

2016-01-01

Ecological evidence suggests that heterotrophic diazotrophs fueled by organic carbon respiration in sediments play an important role in marine nitrogen fixation. However, fundamental knowledge about the identities, abundance, diversity, biogeography, and controlling environmental factors of nitrogen-fixing communities in open ocean sediments is still elusive. Surprisingly, little is known also about nitrogen-fixing communities in sediments of the more research-accessible marginal seas. Here we report on an investigation of the environmental geochemistry and putative diazotrophic microbiota in the sediments of Bohai Sea, an eutrophic marginal sea of the western Pacific Ocean. Diverse and abundant nifH gene sequences were identified and sulfate-reducing bacteria (SRB) were found to be the dominant putative nitrogen-fixing microbes. Community statistical analyses suggested bottom water temperature, bottom water chlorophyll a content (or the covarying turbidity) and sediment porewater Eh (or the covarying pH) as the most significant environmental factors controlling the structure and spatial distribution of the putative diazotrophic communities, while sediment Hg content, sulfide content, and porewater SiO32−-Si content were identified as the key environmental factors correlated positively with the nifH gene abundance in Bohai Sea sediments. Comparative analyses between the Bohai Sea and the northern South China Sea (nSCS) identified a significant composition difference of the putative diazotrophic communities in sediments between the shallow-water (estuarine and nearshore) and deep-water (offshore and deep-sea) environments, and sediment porewater dissolved oxygen content, water depth and in situ temperature as the key environmental factors tentatively controlling the species composition, community structure, and spatial distribution of the marginal sea sediment nifH-harboring microbiota. This confirms the ecophysiological specialization and niche differentiation between the shallow-water and deep-water sediment diazotrophic communities and suggests that the in situ physical and geochemical conditions play a more important role than geographical contiguity in determining the community similarity of the diazotrophic microbiota in marginal sea sediments. PMID:27489551

In Space Nuclear Power as an Enabling Technology for Deep Space Exploration

NASA Technical Reports Server (NTRS)

Sackheim, Robert L.; Houts, Michael

2000-01-01

Deep Space Exploration missions, both for scientific and Human Exploration and Development (HEDS), appear to be as weight limited today as they would have been 35 years ago. Right behind the weight constraints is the nearly equally important mission limitation of cost. Launch vehicles, upper stages and in-space propulsion systems also cost about the same today with the same efficiency as they have had for many years (excluding impact of inflation). Both these dual mission constraints combine to force either very expensive, mega systems missions or very light weight, but high risk/low margin planetary spacecraft designs, such as the recent unsuccessful attempts for an extremely low cost mission to Mars during the 1998-99 opportunity (i.e., Mars Climate Orbiter and the Mars Polar Lander). When one considers spacecraft missions to the outer heliopause or even the outer planets, the enormous weight and cost constraints will impose even more daunting concerns for mission cost, risk and the ability to establish adequate mission margins for success. This paper will discuss the benefits of using a safe in-space nuclear reactor as the basis for providing both sufficient electric power and high performance space propulsion that will greatly reduce mission risk and significantly increase weight (IMLEO) and cost margins. Weight and cost margins are increased by enabling much higher payload fractions and redundant design features for a given launch vehicle (higher payload fraction of IMLEO). The paper will also discuss and summarize the recent advances in nuclear reactor technology and safety of modern reactor designs and operating practice and experience, as well as advances in reactor coupled power generation and high performance nuclear thermal and electric propulsion technologies. It will be shown that these nuclear power and propulsion technologies are major enabling capabilities for higher reliability, higher margin and lower cost deep space missions design to reliably reach the outer planets for scientific exploration.

The effect of diagenesis and fluid migration on rare earth element distribution in pore fluids of the northern Cascadia accretionary margin

USGS Publications Warehouse

Kim, Ji-Hoon; Torres, Marta E.; Haley, Brian A.; Kastner, Miriam; Pohlman, John W.; Riedel, Michael; Lee, Young-Joo

2012-01-01

Analytical challenges in obtaining high quality measurements of rare earth elements (REEs) from small pore fluid volumes have limited the application of REEs as deep fluid geochemical tracers. Using a recently developed analytical technique, we analyzed REEs from pore fluids collected from Sites U1325 and U1329, drilled on the northern Cascadia margin during the Integrated Ocean Drilling Program (IODP) Expedition 311, to investigate the REE behavior during diagenesis and their utility as tracers of deep fluid migration. These sites were selected because they represent contrasting settings on an accretionary margin: a ponded basin at the toe of the margin, and the landward Tofino Basin near the shelf's edge. REE concentrations of pore fluid in the methanogenic zone at Sites U1325 and U1329 correlate positively with concentrations of dissolved organic carbon (DOC) and alkalinity. Fractionations across the REE series are driven by preferential complexation of the heavy REEs. Simultaneous enrichment of diagenetic indicators (DOC and alkalinity) and of REEs (in particular the heavy elements Ho to Lu), suggests that the heavy REEs are released during particulate organic carbon (POC) degradation and are subsequently chelated by DOC. REE concentrations are greater at Site U1325, a site where shorter residence times of POC in sulfate-bearing redox zones may enhance REE burial efficiency within sulfidic and methanogenic sediment zones where REE release ensues. Cross-plots of La concentrations versus Cl, Li and Sr delineate a distinct field for the deep fluids (z > 75 mbsf) at Site U1329, and indicate the presence of a fluid not observed at the other sites drilled on the Cascadia margin. Changes in REE patterns, the presence of a positive Eu anomaly, and other available geochemical data for this site suggest a complex hydrology and possible interaction with the igneous Crescent Terrane, located east of the drilled transect.

Single cell genomic study of dehalogenating Chloroflexi from deep sea sediments of Peruvian Margin

NASA Astrophysics Data System (ADS)

Spormann, A.; Kaster, A.; Meyer-Blackwell, K.; Biddle, J.

2012-12-01

Dehalogenating Chloroflexi, such as Dehalococcoidites (Dhc), are members of the rare biosphere of deep sea sediments but were originally discovered as the key microbes mediating reductive dehalogenation of the prevalent groundwater contaminants tetrachloroethene and trichloroethene to ethene. Dhc are slow growing, highly niche adapted microbes that are specialized to organohalide respiration as the sole mode of energy conservation. These strictly anaerobic microbes depend on a supporting microbial community to mitigate electron donor and cofactor requirements among other factors. Molecular and genomic studies on the key enzymes for energy conservation, reductive dehalogenases, have provided evidence for rapid adaptive evolution in terrestrial environments. However, the metabolic life style of Dhc in the absence of anthropogenic contaminants, such as in pristine deep sea sediments, is still unknown. In order to provide fundamental insights into life style, genomic population structure and evolution of Dhc, we analyzed a non-contaminated deep sea sediment sample of the Peru Margin 1230 site collected 6 mbf by a metagenomic and single cell genomic. We present for the first time single cell genomic data on dehalogenating Chloroflexi, a significant microbial population in the poorly understood oligotrophic marine sub-surface environments.

Single cell genomic study of dehalogenating Chloroflexi in deep sea sediments of Peru Margin 1230

NASA Astrophysics Data System (ADS)

Kaster, A.; Meyer-Blackwell, K.; Biddle, J.; Spormann, A.

2012-12-01

Dehalogenating Chloroflexi, such as Dehalococcoidites (Dhc), are members of the rare biosphere of deep sea sediments but were originally discovered as the key microbes mediating reductive dehalogenation of the prevalent groundwater contaminants tetrachloroethene and trichloroethene to ethene. Dhc are slow growing, highly niche adapted microbes that are specialized to organohalide respiration as the sole mode of energy conservation. They are strictly anaerobic microbes that depend on a supporting microbial community for electron donor and cofactor requirements among other factors. Molecular and genomic studies on the key enzymes for energy conservation, reductive dehalogenases, have provided evidence for rapid adaptive evolution in terrestrial environments. However, the metabolic life style of Dhc in the absence of anthropogenic contaminants, such as in pristine deep sea sediments, is still unknown. In order to provide fundamental insights into life style, genomic population structure and evolution of Dhc, we analyzed a non-contaminated deep sea sediment sample of the Peru Margin 1230 site collected 6 mbsf by a metagenomic and single cell genomic approach. We present for the first time single cell genomic data on dehalogenating Chloroflexi, a significant microbial population in the poorly understood oligotrophic marine sub-surface environment.

Deep structure of the Algerian margin offshore Great Kabylie: Preliminary results of an offshore-onshore seismic profile (SPIRAL campaign)

NASA Astrophysics Data System (ADS)

Chafik, Aidi; Abd el Karim, Yelles; Marie-Odile, Beslier; Frauke, Klingelhoefer; Philippe, Schnurle; Rabah, Bracene; Hamou, Djellit; Audrey, Galve; Laure, Schenini; Françoise, Sage; Abdallah, Bounif Mohand ou; Philippe, Charvis

2013-04-01

In October-November 2009 the Algerian-French SPIRAL research program (Sismique Profonde et Investigation Régionale du Nord de l'ALgérie) was conducted onboard the R/V Atalante in order to understand the deep structure and tectonic history of the Algerian Margin using multichannel and wide-angle seismic data. An extensive dataset was acquired along five regional transects off Algeria, from Arzew Bay to the west, to Annaba to the east. The profiles range from 80 to 180 km long and around 40 ocean-bottom seismometers were deployed on each profile. All profiles were extended on land up to 125 km by land-stations to better constrain the structure of the margin and the nature of the ocean-continent transition zone. We present the preliminary results from modeling of deep and superficial structures in the central Algerian margin, more precisely in the region of the Great Kabylie where a N-S transect of combined wide-angle data using a set of 40 OBS (ocean bottom seismometer) and 24 on-land seismological stations and reflection seismic data was acquired. The profile with a total length of about 260 km (140 km offshore and approximately 124 km onshore), crosses from the north to south the Algeria-Provence Basin, the central Algerian Margin and onshore the geological unit of the Great Kabylie that represents the Kabylides block and the transitional zone between the internal zone (Kabylides) and the external zone in the central Algeria. The network (OBS and seismological stations), recorded 1031 low frequency air gun shots in order to ensure good penetration in the crust. Travel time tomography of first arrivals time of OBS data has yielded a preliminary model of P wave velocities along the profile. In the oceanic domain, a relatively thin crust of about 5 km thickness was imaged overlying a mantle characterized by seismic velocities of about 8 km/s, and covered by a thin sedimentary layer of about 2 km thickness. For the study of the sedimentary cover near the margin several MCS profiles were acquired in this region during the Spiral survey and previously by the Maradja cruise. This data sets allows to image reactivation of the Algerian Margin in this region.

The Northwestern Atlantic Moroccan Margin From Deep Multichannel Seismic Reflection

NASA Astrophysics Data System (ADS)

Malod, J. A.; Réhault, J. P.; Sahabi, M.; Géli, L.; Matias, L.; Zitellini, N.; Sismar Group

The NW Atlantic Moroccan margin, a conjugate of the Nova Scotia margin, is one of the oldest passive margins of the world. Continental break up occurred in the early Jurassic and the deep margin is characterized by a large salt basin. The SISMAR cruise (9 April to 4 May 2001) acquired 3667 km of 360 channel seismic reflection profiles. In addition, refraction data were recorded by means of 48 OBH/OBS deployments. Simultaneously, some of the marine profiles were extended onshore with 16 portable seismic land stations. WNW-ESE profiles 4 and 5 off El Jadida show a good section of the margin. The crustal thinning in this region is fairly abrupt. These profiles image the crust above a strong seismic reflector at about 12 s.twt., interpreted as the Moho. The crust exhibits several different characteristics from the continent towards the ocean.: - highly diffractive with a thickness larger than 25 km beneath the shelf. - stratified at a deep level and topped by few "tilted blocks" with a diffractive acoustic facies and for which 2 hypotheses are proposed: either continental crust tilted during the rifting or large landslides of crustal and sedimentary material slid down later. Liassic evapor- ites are present but seem less thick than to the south. - layered with seaward dipping reflectors: this type of crust correlates with the magnetic anomaly S1 and corresponds to the continent-ocean transition. - diffractive with an oceanic character. Oceanwards, the crust becomes more typically oceanic, but shows internal reflectors that may be re- lated to compressional reactivation during the Tertiary attested by large scale inverted basins. Our results allow us to discuss the nature and location of the continent-ocean transition at a regional scale and the rifting to spreading evolution of the very ma- ture continental margin off El Jadida. This provide us with some constraints for the initial reconstruction between Africa, North America and Iberia. Moreover, these re- sults help to assess the geological hazards linked to the neotectonic activity within the Africa-Eurasia plate boundary. * SISMAR Group includes the authors and Amhrar M., Camurri F., Contrucci I., Diaz J., El Archi A., Gutscher M.A., Jaffal M., Klingelhöfer F., Legall B., Maillard A., Mehdi K., Mercier E., Moulin M., Olivet J.L., Ouajhain B., Perrot J., Rolet J., Ruellan E., Sibuet J.C., Zourarah B.

Diagenetic Carbonates Related to Hydrocarbon-rich Fluid Seepage in the Nile Deep Sea Fan (East Mediterranean Sea)

NASA Astrophysics Data System (ADS)

Pierre, C.; Gontharet, S.; Blanc-Valleron, M. M.; Bayon, G.; Dupré, S.; Mascle, J.

2017-12-01

During the NAUTINIL (September-October 2003), MIMES (July 2004), BIONIL (October 2006) and MEDECO2 (November 2007) cruises, coring and submersible dives were realized in the Nile Deep Sea Fan (NDSF) area. Active fluid venting sites were identified by the presence of living benthic organisms and by methane plumes in the bottom waters above the seeping structures. At all sites, hard carbonate crusts cover irregularly the sea floor. The sediments from the venting areas are organic-rich, contain sometimes carbonate concretions and have a strong H2S smell indicative of active sulfate reduction. The mineralogy of carbonate crusts is dominated by aragonite and Mg-calcite; the mineralogy of concretions is more complex, with mixtures of Mg-calcite, dolomite and ankerite. The oxygen and carbon isotopic compositions of the carbonate from crusts and concretions exhibit large variations (-2.8< δ18O ‰ VPDB <+9.5; -42.6< δ13C ‰ VPDB <+22.4). The wide range of δ18O values reflects variable sources of fluids. Most of the authigenic carbonates from the NDSF were precipitated in isotopic equilibrium with the Mediterranean bottom water. The carbonate crusts and concretions from the brine seeps of the north-western NDSF are enriched in 18O indicating that a source of 18O-rich fluids originated from depth. Differently, a few crusts and concretions from the eastern NDSF exhibit relatively low δ18O values, which are due to precipitation at warm temperatures. The very low δ13C values of the diagenetic carbonates indicate that methane and possibly other heavier hydrocarbons were the major source of carbon that was oxidized as bicarbonate mostly through bacterial sulfate reduction coupled with anaerobic methane oxidation within the anoxic sediment. The very positive δ13C values of the diagenetic carbonates from many carbonate concretions are related to the production of 13C-rich CO2 during methanogenesis within the sub-seafloor sediments.

Sedimentary Markers : a window into deep geodynamic processes Examples from the Western Mediterranean Sea

NASA Astrophysics Data System (ADS)

Rabineau, Marina; Aslanian, Daniel; Leroux, Estelle; Pellen, Romain; Gorini, Christian; Moulin, Maryline; Droz, Laurence; Bache, Francois; Molliex, Stephane; Silenzario, Carmine; Rubino, Jean-Loup

2017-04-01

Deep Earth dynamics impact so strongly on surface geological processes that we can use sediment palaeo-markers as a window into the deeper Earth. Derived from climatic and tectonic erosive actions on the continents, and related to eustasy, subsidence and isostasy, the sediment in a deep basin is the main recorder of these processes. Nevertheless, defining and quantifying the relative roles of parameters that interact to give the final sedimentary architecture is not a simple task. Using a 3D-grid of seismic and wide-angle data, boreholes and numerical stratigraphic modelling, we propose here a quantification of post-rift vertical movements in the Provençal Basin (Western Mediterranean) involving three domains of subsidence: seaward tilting on the platform and the slope and purely vertical subsidence in the deep basin (Rabineau et al., 2014 ; Leroux et al., 2015). These domains fit the deeper crustal domains highlighted by previous geophysical data (Moulin et al., 2015 ; Afilhado et al., 2015). Post-break-up sedimentary markers may therefore be used to identify the initial hinge lines of the rifting phase, to quantify sedimentation rates and isostatic rebound (Rabineau et al., 2014) and redefine the subsidence laws. Similar work and results are obtained in the Valencia Basin (Pellen et al., 2016). This Western Mediterranean Sea is a natural laboratory with very high total subsidence rates that enable high sedimentation rates along the margin with sediments provided by the Rhône and Ebro rivers flowing from the Alps, the Pyrennees and Catalan chains, which in turn archives the detailed record of climate/tectonic evolution during the Neogene. The Western Mediterranean Sea could therefore further probe deep-earth and surface connections using deep drillings of this land-locked ocean basin transformed into a giant saline basin (Rabineau et al., 2015). Leroux, E., Aslanian, D., Rabineau, M., M. Moulin, D. Granjeon, C. Gorini, L. Droz, 2015. Sedimentary markers: a window to deep geodynamic processes. Terra Nova 27, 122-129. Moulin, M., Klingelhoefer, F., Afilhado, A., Feld, A., Aslanian, D., Schnurle, P., Nouzé, H., Rabineau, M. & Beslier, M.O., 2015. Deep crustal structure across an young passive margin from wide- angle and reflection seismic date (The SARDINIA Experiment) - I- Gulf of Lion's Margin BSGF, ILP Special Volume, 186 (4-5), pp. 309-330 Afilhado A., M. Moulin, F. Klingelhoefer, D. Aslanian, P. Schnurle, H. Nouzé, M. Rabineau & M.O. Beslier, 2015. Deep crustal structure across a young passive margin from wide- angle and reflection seismic data (The SARDINIA Experiment) - II. Sardinia's margin, BSGF, ILP Special Volume, 186 (4-5), p. 331-351 Pellen, R., Aslanian, D., Rabineau, M., Leroux, E., Gorini, C., Silenzario, C., Blanpied, C., Rubino, J-L., 2016. The Minorca Basin: a buffer zone between Valencia and Provençal Basins, Terra Nova, 28-4, p. 245-256. Rabineau, M., Leroux, E., Aslanian, D., Bache, F., Gorini, C., Moulin, M., Molliex, S., Droz, L., Dos Reis, T., Rubino, J-L., Olivet, J-L., 2014. Quantifying Subsidence and Isostasy using paleobathymetric markers : example from the Gulf of Lion, EPSL, vol. 288, p. 353- 366. http://dx.doi.org/10.1016/j.epsl.2013.11.059 Rabineau, M., S. Cloetingh, J. Kuroda, D. Aslanian, A Droxler, C. Gorini, D. Garcia-Castellanos, A. Moscariello, Y. Hello, E. Burov, F. Sierro, F. Lirer, F. Roure, P.A. Pezard, L. Matenco, Y. Mart, A. Camerlenghi, A. Tripati and the GOLD and DREAM Working Groups, 2015. Probing connections between deep earth and surface processes in a land-locked ocean basin transformed into a giant saline basin: the Mediterranean GOLD project, Marine and Petroleum Geology, Volume: 66 Pages: 6-17.

Nile River Fluctuations Near Khartoum, Sudan

NASA Image and Video Library

2001-08-29

Throughout history, the rising and falling waters of the mighty Nile River have directly impacted the lives of the people who live along its banks. These images of the area around Sudan's capital city of Khartoum capture the river's dynamic nature. Acquired by the Multi-angle Imaging SpectroRadiometer's nadir (vertical-viewing) camera, they display the extent of the Nile waters before and after the onset of the rainy seasons of 2000 (top pair) and 2001 (bottom pair). The images are displayed in "false color," using the camera's near-infrared, green, and blue bands. With this particular spectral combination, water appears in shades of blue and turquoise, and highly vegetated areas show up as bright red. Originating in Uganda and Ethiopia, respectively, the waters of the White Nile (western branch) and Blue Nile (eastern branch) converge at Khartoum (about half-way between image center and the left-hand side), and continue to flow northward as the Great Nile. Although the most obvious feature in these images is the increased width of the White Nile between spring and summer, careful inspection shows that the Great Nile is at its widest in August 2001 (note in particular the area between the clouds near the top of this panel). Heavy rains in the Blue Nile catchment area of the Ethiopian highlands led to a rapid overflow of the river's floodwaters into the main stream of the Great Nile, leading to extensive flooding, the worst effects of which occurred north of Khartoum. According to the Food and Agriculture Organization of the United Nations, tens of thousands of people have fled their homes, and the number of people in need of urgent food assistance in Sudan, estimated at three million earlier in the year, was likely to increase with the onset of these floods. South of the confluence of the White Nile and the Blue Nile, the area of a cross-hatched appearance is the irrigated plain of El Gezira. The Gezira irrigation scheme uses water from the Makwar Dam (now called the Sennar Dam), located across the Blue Nile south of Khartoum. Among the main agricultural products of this region are cotton, millet, peanuts and fodder crops. Overall prospects for Sudan's 2001 grain crop were already poor prior to the flooding due to a late start of the rainy season in parts of the country. Following two consecutive years of serious drought, precipitation arrived too late to save the grain harvest that normally begins in late August. Lower harvests for the past two years coupled with depletion of stocks have led to a rise in cereal prices, reducing access to food for the Sudan's poorer citizens, already suffering from the effects of Africa's longest running civil war. Each of these images represents an area of about 130 kilometers x 150 kilometers. The data were obtained during Terra orbits 1922, 3553, 7281, and 8912. http://photojournal.jpl.nasa.gov/catalog/PIA03420

Phylogenetic analysis of West Nile virus, Nuevo Leon State, Mexico.

PubMed

Blitvich, Bradley J; Fernández-Salas, Ildefonso; Contreras-Cordero, Juan F; Loroño-Pino, María A; Marlenee, Nicole L; Díaz, Francisco J; González-Rojas, José I; Obregón-Martínez, Nelson; Chiu-García, Jorge A; Black, William C; Beaty, Barry J

2004-07-01

West Nile virus RNA was detected in brain tissue from a horse that died in June 2003 in Nuevo Leon State, Mexico. Nucleotide sequencing and phylogenetic analysis of the premembrane and envelope genes showed that the virus was most closely related to West Nile virus isolates collected in Texas in 2002.

Phylogenetic Analysis of West Nile Virus, Nuevo Leon State, Mexico

PubMed Central

Blitvich, Bradley J.; Fernández-Salas, Ildefonso; Contreras-Cordero, Juan F.; Loroño-Pino, María A.; Marlenee, Nicole L.; Díaz, Francisco J.; González-Rojas, José I.; Obregón-Martínez, Nelson; Chiu-García, Jorge A.; Black, William C.

2004-01-01

West Nile virus RNA was detected in brain tissue from a horse that died in June 2003 in Nuevo Leon State, Mexico. Nucleotide sequencing and phylogenetic analysis of the premembrane and envelope genes showed that the virus was most closely related to West Nile virus isolates collected in Texas in 2002. PMID:15324558

Identification and transcriptional profile of multiple genes in the posterior kidney of Nile tilapia at 6h post bacterial infections

USDA-ARS?s Scientific Manuscript database

To understand the molecular mechanisms involved in response of Nile tilapia (Oreochromis niloticus) to bacterial infection, suppression subtractive cDNA hybridization technique was used to identify upregulated genes in the posterior kidney of Nile tilapia at 6h post infection with Aeromonas hydrophi...

78 FR 16505 - Prospective Grant of Exclusive License: Chimeric West Nile/Dengue Viruses

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-15

... Grant of Exclusive License: Chimeric West Nile/Dengue Viruses AGENCY: Centers for Disease Control and... giving an exclusive license, in the field of use of in vitro diagnostics for dengue virus infection, to.... Provisional Application 61/049,342, filed 4/30/2008, entitled ``Engineered, Chimeric West Nile/Dengue Viruses...

Crystal Structure of West Nile Virus Envelope Glycoprotein Reveals Viral Surface Epitopes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kanai,R.; Kar, K.; Anthony, K.

2006-01-01

West Nile virus, a member of the Flavivirus genus, causes fever that can progress to life-threatening encephalitis. The major envelope glycoprotein, E, of these viruses mediates viral attachment and entry by membrane fusion. We have determined the crystal structure of a soluble fragment of West Nile virus E. The structure adopts the same overall fold as that of the E proteins from dengue and tick-borne encephalitis viruses. The conformation of domain II is different from that in other prefusion E structures, however, and resembles the conformation of domain II in postfusion E structures. The epitopes of neutralizing West Nile virus-specificmore » antibodies map to a region of domain III that is exposed on the viral surface and has been implicated in receptor binding. In contrast, we show that certain recombinant therapeutic antibodies, which cross-neutralize West Nile and dengue viruses, bind a peptide from domain I that is exposed only during the membrane fusion transition. By revealing the details of the molecular landscape of the West Nile virus surface, our structure will assist the design of antiviral vaccines and therapeutics.« less

Regional view of a Trans-African Drainage System.

PubMed

Abdelkareem, Mohamed; El-Baz, Farouk

2015-05-01

Despite the arid to hyperarid climate of the Great Sahara of North Africa, pluvial climates dominated the region. Radar data shed some light on the postulated Trans-African Drainage System and its relationship to active and inactive tributaries of the Nile basin. Interpretations of recent elevation data confirm a source of the river water from the Red Sea highlands did not connect the Atlantic Ocean across Tushka basin, highlands of Uwinate and Darfur, and Chad basin, but northward to the ancestral Nile Delta. Elements of topography and climate were considered. They show that the former segments of the Nile closely mirror present-day tributaries of the Nile basin in drainage geometry, landscape, and climate. A rainfall data interpolation scenario revealed that this basin received concurrent runoff from both flanks such as Gabgaba-Allaqi to the east and Tushka basin to the west, similar to present-day Sobat and White Nile tributaries, respectively. Overall the western tributaries such as those of Tushka basin and Howar lead to the Nile, which was (and still is) the biggest river system in Africa.

Regional view of a Trans-African Drainage System

PubMed Central

Abdelkareem, Mohamed; El-Baz, Farouk

2014-01-01

Despite the arid to hyperarid climate of the Great Sahara of North Africa, pluvial climates dominated the region. Radar data shed some light on the postulated Trans-African Drainage System and its relationship to active and inactive tributaries of the Nile basin. Interpretations of recent elevation data confirm a source of the river water from the Red Sea highlands did not connect the Atlantic Ocean across Tushka basin, highlands of Uwinate and Darfur, and Chad basin, but northward to the ancestral Nile Delta. Elements of topography and climate were considered. They show that the former segments of the Nile closely mirror present-day tributaries of the Nile basin in drainage geometry, landscape, and climate. A rainfall data interpolation scenario revealed that this basin received concurrent runoff from both flanks such as Gabgaba-Allaqi to the east and Tushka basin to the west, similar to present-day Sobat and White Nile tributaries, respectively. Overall the western tributaries such as those of Tushka basin and Howar lead to the Nile, which was (and still is) the biggest river system in Africa. PMID:26257941

Aggressiveness overcomes body-size effects in fights staged between invasive and native fish species with overlapping niches.

PubMed

Sanches, Fábio Henrique Carretero; Miyai, Caio Akira; Costa, Tânia Márcia; Christofoletti, Ronaldo Adriano; Volpato, Gilson Luiz; Barreto, Rodrigo Egydio

2012-01-01

Approximately 50 years ago, Nile tilapia were accidentally introduced to Brazil, and the decline of pearl cichlid populations, which has been intensified by habitat degradation, in some locations has been associated with the presence of Nile tilapia. There is, however, little strong empirical evidence for the negative interaction of non-native fish populations with native fish populations; such evidence would indicate a potential behavioural mechanism that could cause the population of the native fish to decline. In this study, we show that in fights staged between pairs of Nile tilapia and pearl cichlids of differing body size, the Nile tilapia were more aggressive than the pearl cichlid. Because this effect prevailed over body-size effects, the pearl cichlids were at a disadvantage. The niche overlap between the Nile tilapia and the pearl cichlid in nature, and the competitive advantage shown by the Nile tilapia in this study potentially represent one of several possible results of the negative interactions imposed by an invasive species. These negative effects may reduce population viability of the native species and cause competitive exclusion.

Continental margin sedimentation: From sediment transport to sequence stratigraphy

USGS Publications Warehouse

Nittrouer, Charles A.; Austin, James A.; Field, Michael E.; Kravitz, Joseph H.; Syvitski, James P. M.; Wiberg, Patricia L.

2007-01-01

This volume on continental margin sedimentation brings together an expert editorial and contributor team to create a state-of-the-art resource. Taking a global perspective, the book spans a range of timescales and content, ranging from how oceans transport particles, to how thick rock sequences are formed on continental margins.- Summarizes and integrates our understanding of sedimentary processes and strata associated with fluvial dispersal systems on continental shelves and slopes- Explores timescales ranging from particle transport at one extreme, to deep burial at the other- Insights are presented for margins in general, and with focus on a tectonically active margin (northern California) and a passive margin (New Jersey), enabling detailed examination of the intricate relationships between a wide suite of sedimentary processes and their preserved stratigraphy- Includes observational studies which document the processes and strata found on particular margins, in addition to numerical models and laboratory experimentation, which provide a quantitative basis for extrapolation in time and space of insights about continental-margin sedimentation- Provides a research resource for scientists studying modern and ancient margins, and an educational text for advanced students in sedimentology and stratigraphy

Cairo, Egypt as seen from STS-62

NASA Image and Video Library

1994-03-05

STS062-108-058 (4-18 March 1994) --- Cairo lies at the apex of the great delta of the Nile: the delta is marked by the strong greens of cultivated lands, Cairo by the gray sprawl along the river and the eastern delta apex as it develops in the direction of the airports and Suez. The city of El Giza lies on the west side of the Nile with the Giza pyramids in the desert just beyond the cultivated lands. Several major canals lead water to parts of the delta more distant from the Nile; generally these can be recognized as straighter, more engineered waterways. Towards the top left, the bifurcation of the Rosetta and Damietta branches of the Nile can be seen. These are the two major present-day veins of the Nile as it approaches the Mediterranean.

The Nile River

NASA Technical Reports Server (NTRS)

2002-01-01

This image of the northern portion of the Nile River was captured by MISR's nadir camera on January 30, 2001 (Terra orbit 5956). The Nile is the longest river in the world, extending for about 6700 kilometers from its headwaters in the highlands of eastern Africa. At the apex of the fertile Nile River Delta is the Egyptian capital city of Cairo. To the west are the Great Pyramids of Giza. North of here the Nile branches into two distributaries, the Rosetta to the west and the Damietta to the east. Also visible in this image is the Suez Canal, a shipping waterway connecting Port Said on the Mediterranean Sea with the Gulf of Suez. The Gulf is an arm of the Red Sea, and is located on the righthand side of the picture. Image credit: NASA/GSFC/LaRC/JPL, MISR Team.

Normal haematology and blood biochemistry of wild Nile crocodiles (Crocodylus niloticus) in the Okavango Delta, Botswana.

PubMed

Lovely, C J; Pittman, J M; Leslie, A J

2007-09-01

Wild Nile crocodiles (Crocodylus niloticus) of various size classes were captured in the Okavango Delta, Botswana. Blood was collected from the post occipital sinus and used for the determination of a wide range of haematological and biochemical parameters. These values were compared between the sexes and between 3 size classes. The values were also compared with the limited data available from farmed Nile crocodiles, as well as from other wild Nile crocodiles. The Okavango crocodiles were comparatively anaemic, and had comparatively low total protein and blood glucose levels. There was a high prevalence of Hepatozoon pettiti infection, however, there was no significant difference in haematological values between the infected and uninfected crocodiles. The values reported here will be useful in diagnostic investigations in both zoo and farmed Nile crocodiles.

Taxonomy, distribution and ecology of the order Phyllodocida (Annelida, Polychaeta) in deep-sea habitats around the Iberian margin

NASA Astrophysics Data System (ADS)

Ravara, Ascensão; Ramos, Diana; Teixeira, Marcos A. L.; Costa, Filipe O.; Cunha, Marina R.

2017-03-01

The polychaetes of the order Phyllodocida (excluding Nereidiformia and Phyllodociformia incertae sedis) collected from deep-sea habitats of the Iberian margin (Bay of Biscay, Horseshoe continental rise, Gulf of Cadiz and Alboran Sea), and Atlantic seamounts (Gorringe Bank, Atlantis and Nameless) are reported herein. Thirty-six species belonging to seven families - Acoetidae, Pholoidae, Polynoidae, Sigalionidae, Glyceridae, Goniadidae and Phyllodocidae, were identified. Amended descriptions and/or new illustrations are given for the species Allmaniella setubalensis, Anotochaetonoe michelbhaudi, Lepidasthenia brunnea and Polynoe sp. Relevant taxonomical notes are provided for other seventeen species. Allmaniella setubalensis, Anotochaetonoe michelbhaudi, Harmothoe evei, Eumida longicirrata and Glycera noelae, previously known only from their type localities were found in different deep-water places of the studied areas and constitute new records for the Iberian margin. The geographic distributions and the bathymetric range of thirteen and fifteen species, respectively, are extended. The morphology-based biodiversity inventory was complemented with DNA sequences of the mitochondrial barcode region (COI barcodes) providing a molecular tag for future reference. Twenty new sequences were obtained for nine species in the families Acoetidae, Glyceridae and Polynoidae and for three lineages within the Phylodoce madeirensis complex (Phyllodocidae). A brief analysis of the newly obtained sequences and publicly available COI barcode data for the genera herein reported, highlighted several cases of unclear taxonomic assignments, which need further study.

Understanding the hydrologic sources and sinks in the Nile Basin using multisource climate and remote sensing data sets

USGS Publications Warehouse

Senay, Gabriel; Velpuri, Naga Manohar; Bohms, Stefanie; Demissie, Yonas; Gebremichael, Mekonnen

2014-01-01

In this study, we integrated satellite-drived precipitation and modeled evapotranspiration data (2000–2012) to describe spatial variability of hydrologic sources and sinks in the Nile Basin. Over 2000–2012 period, 4 out of 11 countries (Ethiopia, Tanzania, Kenya, and Uganda) in the Nile Basin showed a positive water balance while three downstream countries (South Sudan, Sudan, and Egypt) showed a negative balance. Gravity Recovery and Climate Experiment (GRACE) mass deviation in storage data analysis showed that at annual timescales, the Nile Basin storage change is substantial while over longer time periods, it is minimal (<1% of basin precipitation). We also used long-term gridded runoff and river discharge data (1869–1984) to understand the discrepancy in the observed and expected flow along the Nile River. The top three countries that contribute most to the flow are Ethiopia, Tanzania, and Kenya. The study revealed that ∼85% of the runoff generated in the equatorial region is lost in an interstation basin that includes the Sudd wetlands in South Sudan; this proportion is higher than the literature reported loss of 50% at the Sudd wetlands alone. The loss in runoff and flow volume at different sections of the river tend to be more than what can be explained by evaporation losses, suggesting a potential recharge to deeper aquifers that are not connected to the Nile channel systems. On the other hand, we also found that the expected average annual Nile flow at Aswan is greater (97 km3) than the reported amount (84 km3). Due to the large variations of the reported Nile flow at different locations and time periods, the study results indicate the need for increased hydrometeorological instrumentation of the basin. The study also helped improve our understanding of the spatial dynamics of water sources and sinks in the Nile Basin and identified emerging hydrologic questions that require further attention.

Understanding the hydrologic sources and sinks in the Nile Basin using multisource climate and remote sensing data sets

NASA Astrophysics Data System (ADS)

Senay, Gabriel B.; Velpuri, Naga Manohar; Bohms, Stefanie; Demissie, Yonas; Gebremichael, Mekonnen

2014-11-01

In this study, we integrated satellite-drived precipitation and modeled evapotranspiration data (2000-2012) to describe spatial variability of hydrologic sources and sinks in the Nile Basin. Over 2000-2012 period, 4 out of 11 countries (Ethiopia, Tanzania, Kenya, and Uganda) in the Nile Basin showed a positive water balance while three downstream countries (South Sudan, Sudan, and Egypt) showed a negative balance. Gravity Recovery and Climate Experiment (GRACE) mass deviation in storage data analysis showed that at annual timescales, the Nile Basin storage change is substantial while over longer time periods, it is minimal (<1% of basin precipitation). We also used long-term gridded runoff and river discharge data (1869-1984) to understand the discrepancy in the observed and expected flow along the Nile River. The top three countries that contribute most to the flow are Ethiopia, Tanzania, and Kenya. The study revealed that ˜85% of the runoff generated in the equatorial region is lost in an interstation basin that includes the Sudd wetlands in South Sudan; this proportion is higher than the literature reported loss of 50% at the Sudd wetlands alone. The loss in runoff and flow volume at different sections of the river tend to be more than what can be explained by evaporation losses, suggesting a potential recharge to deeper aquifers that are not connected to the Nile channel systems. On the other hand, we also found that the expected average annual Nile flow at Aswan is greater (97 km3) than the reported amount (84 km3). Due to the large variations of the reported Nile flow at different locations and time periods, the study results indicate the need for increased hydrometeorological instrumentation of the basin. The study also helped improve our understanding of the spatial dynamics of water sources and sinks in the Nile Basin and identified emerging hydrologic questions that require further attention.

Deep structure of the continental margin and basin off Greater Kabylia, Algeria - New insights from wide-angle seismic data modeling and multichannel seismic interpretation

NASA Astrophysics Data System (ADS)

Aïdi, Chafik; Beslier, Marie-Odile; Yelles-Chaouche, Abdel Karim; Klingelhoefer, Frauke; Bracene, Rabah; Galve, Audrey; Bounif, Abdallah; Schenini, Laure; Hamai, Lamine; Schnurle, Philippe; Djellit, Hamou; Sage, Françoise; Charvis, Philippe; Déverchère, Jacques

2018-03-01

During the Algerian-French SPIRAL survey aimed at investigating the deep structure of the Algerian margin and basin, two coincident wide-angle and reflection seismic profiles were acquired in central Algeria, offshore Greater Kabylia, together with gravimetric, bathymetric and magnetic data. This 260 km-long offshore-onshore profile spans the Balearic basin, the central Algerian margin and the Greater Kabylia block up to the southward limit of the internal zones onshore. Results are obtained from modeling and interpretation of the combined data sets. The Algerian basin offshore Greater Kabylia is floored by a thin oceanic crust ( 4 km) with P-wave velocities ranging between 5.2 and 6.8 km/s. In the northern Hannibal High region, the atypical 3-layer crustal structure is interpreted as volcanic products stacked over a thin crust similar to that bordering the margin and related to Miocene post-accretion volcanism. These results support a two-step back-arc opening of the west-Algerian basin, comprising oceanic crust accretion during the first southward stage, and a magmatic and probably tectonic reworking of this young oceanic basement during the second, westward, opening phase. The structure of the central Algerian margin is that of a narrow ( 70 km), magma-poor rifted margin, with a wider zone of distal thinned continental crust than on the other margin segments. There is no evidence for mantle exhumation in the sharp ocean-continent transition, but transcurrent movements during the second opening phase may have changed its initial geometry. The Plio-Quaternary inversion of the margin related to ongoing convergence between Africa and Eurasia is expressed by a blind thrust system under the margin rising toward the surface at the slope toe, and by an isostatic disequilibrium resulting from opposite flexures of two plates decoupled at the continental slope. This disequilibrium is likely responsible for the peculiar asymmetrical shape of the crustal neck that may thus be a characteristic feature of inverted rifted margins.

N Isotopes in Nile Sediments (ethiopia, Sudan)

NASA Astrophysics Data System (ADS)

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

2009-04-01

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

Crustal structure of the Ionian basin and eastern Sicily margin : results from a wide angle seismic survey and implication for the crustal nature and origin of the basin, and the recent tear fault location

NASA Astrophysics Data System (ADS)

Gutscher, M. A.; Dellong, D.; Klingelhoefer, F.; Kopp, H.; Graindorge, D.; Margheriti, L.; Moretti, M.

2017-12-01

In the Ionian Sea (Central Mediterranean) the slow convergence between Africa and Eurasia results in the formation of a narrow subduction zone. The nature of the crust and lithosphere of the subducting plate remain debated and could represent the last remnants of the Neo-Tethys ocean. The rifting mechanism that produced the Ionian basin are also still under discussion with the Malta escarpment representing a possible remnant of this opening. At present, this subduction is still retreating to the south-east (motion occurring since the last 35 Ma) but is confined to the narrow Ionian Basin. In order to accommodate slab roll-back, a major lateral slab tear fault is required. This fault is thought to propagate along the eastern Sicily margin but its precise location remains controversial. This study focuses on the deep crustal structure of the Eastern-Sicily margin and the Malta Escarpment by presenting two wide-angle velocity profiles crossing these structures roughly orthogonally. The data used for the forward velocity modeling were acquired onboard the R/V Meteor during the DIONYSUS cruise in 2014. The results image an oceanic crust within the Ionian basin as well as the deep structure of the Malta Escarpment which presents characteristics of a transform margin. A deep and asymmetrical sedimentary basin is imaged south of the Messina strait and seems to have opened in between the Calabrian and Peloritan continental terranes. The interpretation of the velocity models suggests that the tear fault is located east of the Malta Escarpment, along the Alfeo fault system.

The polyphased tectonic evolution of the Anegada Passage in the northern Lesser Antilles subduction zone

NASA Astrophysics Data System (ADS)

Laurencin, M.; Marcaillou, B.; Graindorge, D.; Klingelhoefer, F.; Lallemand, S.; Laigle, M.; Lebrun, J.-F.

2017-05-01

The influence of the highly oblique plate convergence at the northern Lesser Antilles onto the margin strain partitioning and deformation pattern, although frequently invoked, has never been clearly imaged. The Anegada Passage is a set of basins and deep valleys, regularly related to the southern boundary of the Puerto Rico-Virgin Islands (PRVI) microplate. Despite the publications of various tectonic models mostly based on bathymetric data, the tectonic origin and deformation of this Passage remains unconstrained in the absence of deep structure imaging. During cruises Antithesis 1 and 3 (2013-2016), we recorded the first deep multichannel seismic images and new multibeam data in the northern Lesser Antilles margin segment in order to shed a new light on the structure and tectonic pattern of the Anegada Passage. We image the northeastern extent of the Anegada Passage, from the Sombrero Basin to the Lesser Antilles margin front. Our results reveal that this northeastern segment is an EW trending left-stepping en échelon strike-slip system that consists of the Sombrero and Malliwana pull-apart basins, the Malliwana and Anguilla left-lateral faults, and the NE-SW compressional restraining bend at the Malliwana Hill. Reviewing the structure of the Anegada Passage, from the south of Puerto Rico to the Lesser Antilles margin front, reveals a polyphased tectonic history. The Anegada Passage is formed by a NW-SE extension, possibly related to the rotation or escape of PRVI block due to collision of the Bahamas Bank. Currently, it is deformed by an active WNW-ESE strike-slip deformation associated to the shear component of the strain partitioning resulting from the subduction obliquity.

Fluid mixing and the deep biosphere of a fossil Lost City-type hydrothermal system at the Iberia Margin.

PubMed

Klein, Frieder; Humphris, Susan E; Guo, Weifu; Schubotz, Florence; Schwarzenbach, Esther M; Orsi, William D

2015-09-29

Subseafloor mixing of reduced hydrothermal fluids with seawater is believed to provide the energy and substrates needed to support deep chemolithoautotrophic life in the hydrated oceanic mantle (i.e., serpentinite). However, geosphere-biosphere interactions in serpentinite-hosted subseafloor mixing zones remain poorly constrained. Here we examine fossil microbial communities and fluid mixing processes in the subseafloor of a Cretaceous Lost City-type hydrothermal system at the magma-poor passive Iberia Margin (Ocean Drilling Program Leg 149, Hole 897D). Brucite-calcite mineral assemblages precipitated from mixed fluids ca. 65 m below the Cretaceous paleo-seafloor at temperatures of 31.7 ± 4.3 °C within steep chemical gradients between weathered, carbonate-rich serpentinite breccia and serpentinite. Mixing of oxidized seawater and strongly reducing hydrothermal fluid at moderate temperatures created conditions capable of supporting microbial activity. Dense microbial colonies are fossilized in brucite-calcite veins that are strongly enriched in organic carbon (up to 0.5 wt.% of the total carbon) but depleted in (13)C (δ(13)C(TOC) = -19.4‰). We detected a combination of bacterial diether lipid biomarkers, archaeol, and archaeal tetraethers analogous to those found in carbonate chimneys at the active Lost City hydrothermal field. The exposure of mantle rocks to seawater during the breakup of Pangaea fueled chemolithoautotrophic microbial communities at the Iberia Margin, possibly before the onset of seafloor spreading. Lost City-type serpentinization systems have been discovered at midocean ridges, in forearc settings of subduction zones, and at continental margins. It appears that, wherever they occur, they can support microbial life, even in deep subseafloor environments.

Fluid mixing and the deep biosphere of a fossil Lost City-type hydrothermal system at the Iberia Margin

PubMed Central

Klein, Frieder; Humphris, Susan E.; Guo, Weifu; Schubotz, Florence; Schwarzenbach, Esther M.; Orsi, William D.

2015-01-01

Subseafloor mixing of reduced hydrothermal fluids with seawater is believed to provide the energy and substrates needed to support deep chemolithoautotrophic life in the hydrated oceanic mantle (i.e., serpentinite). However, geosphere-biosphere interactions in serpentinite-hosted subseafloor mixing zones remain poorly constrained. Here we examine fossil microbial communities and fluid mixing processes in the subseafloor of a Cretaceous Lost City-type hydrothermal system at the magma-poor passive Iberia Margin (Ocean Drilling Program Leg 149, Hole 897D). Brucite−calcite mineral assemblages precipitated from mixed fluids ca. 65 m below the Cretaceous paleo-seafloor at temperatures of 31.7 ± 4.3 °C within steep chemical gradients between weathered, carbonate-rich serpentinite breccia and serpentinite. Mixing of oxidized seawater and strongly reducing hydrothermal fluid at moderate temperatures created conditions capable of supporting microbial activity. Dense microbial colonies are fossilized in brucite−calcite veins that are strongly enriched in organic carbon (up to 0.5 wt.% of the total carbon) but depleted in 13C (δ13CTOC = −19.4‰). We detected a combination of bacterial diether lipid biomarkers, archaeol, and archaeal tetraethers analogous to those found in carbonate chimneys at the active Lost City hydrothermal field. The exposure of mantle rocks to seawater during the breakup of Pangaea fueled chemolithoautotrophic microbial communities at the Iberia Margin, possibly before the onset of seafloor spreading. Lost City-type serpentinization systems have been discovered at midocean ridges, in forearc settings of subduction zones, and at continental margins. It appears that, wherever they occur, they can support microbial life, even in deep subseafloor environments. PMID:26324888

Natural constraints on exploring Antarctica's continental margin, existing geophysical and geological data basis, and proposed drilling program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, J.B.

1987-05-01

There have been a number of multichannel seismic reflection and seismic refraction surveys of the Antarctic continental shelf. While glacial erosion has left acoustic basement exposed on portions of the inner shelf, thick sedimentary sequences occur on the passive margin of east Antarctica. The thickness and age of these strata vary due to different breakup histories of the margin. Several sedimentary basins have been identified. Most are rift basins formed during the early stages of Antarctica's separation from other Gondwana continents and plateaus. The west Antarctic continental shelf is extensive, being approximately twice the size of the Gulf of Mexicomore » shelf. It has been poorly surveyed to date, owing mainly to its perennial sea ice cover. Gradual subduction of the spreading center from south to north along the margin resulted in old active margin sequences being buried beneath passive margin sequences. The latter should increase in thickness from north to south along the margin although no data bear this out. Hydrocarbon potential on the northern portion of the west Antarctic margin is considered low due to a probable lack of reservoir rocks. Establishment of ice sheets on Antarctica caused destruction of land vegetation and greatly restricted siliciclastic sand-producing environments. So only sedimentary basins which contain pre-early Miocene deposits have good hydrocarbon prospectivity. The Antarctic continental shelf is the deepest in the world, averaging 500 m and in places being more than a kilometer deep. The shelf has been left rugged by glacial erosion and is therefore prone to sediment mass movement. Widespread sediment gravity flow deposits attest to this. The shelf is covered with sea ice most of the year and in a few areas throughout the year. Icebergs, drift freely in the deep waters of the shelf; drift speeds of 1 to 2.5 km/year are not uncommon.« less

Discovery of asphalt seeps in the deep Southwest Atlantic off Brazil

NASA Astrophysics Data System (ADS)

Fujikura, Katsunori; Yamanaka, Toshiro; Sumida, Paulo Y. G.; Bernardino, Angelo F.; Pereira, Olivia S.; Kanehara, Toshiyuki; Nagano, Yuriko; Nakayama, Cristina R.; Nobrega, Marcos; Pellizari, Vivian H.; Shigeno, Shuichi; Yoshida, Takao; Zhang, Jing; Kitazato, Hiroshi

2017-12-01

The discovery and description of cold seeps with deep-sea chemosynthetic communities in the Southwest Atlantic Ocean are still incomplete, despite the large proven oil and gas reserves off the coast of Brazil. In the southeastern Brazilian continental margin, where over 71% of the country's oil and gas production takes place, there are previous geological and qualitative biological evidence of seep biota associated with pockmarks on the upper slope of the Santos Basin. In order to further study seep ecosystems on the Brazilian margin, a deep-sea investigation named Iatá-Piúna cruise was conducted using the human-occupied vehicle Shinkai 6500 off Brazil's southeast continental margin. Asphalt seeps were discovered on the seafloor of the North São Paulo Plateau from depths of 2652-2752 m, representing only the third discovery of this type of seep worldwide, following those in the Gulf of Mexico and off Angola. Video and isotopic analyses indicated a number of megabenthic animals in the asphalt seeps in the North São Paulo Plateau and revealed typical deep-sea heterotrophic and photosynthesis-based fauna occupying hard substrates provided by the asphalt seep. There was no evidence of chemosynthesis-based megabenthic fauna such as vesicomyid clams, Bathymodiolus mussels, and siboglinid tube worms, or any sediment bacterial mats, gas seepage, and carbonate rock in/around the seeps. The benthic fauna was composed mainly of sponges (ca. 15 species), such as the hexactinellids Caulophacus sp., Poliopogon amadou, Saccocalyx pedunculatus, Farrea occa and cf. Chonelasma choanoides; besides typical deep-sea isidid octocorals, brisingid starfishes and galatheid crabs. The δ13C values of poriferan sponges suggested a heterotrophic and pelagic nutrition. Geochemical analyses of asphalt revealed a heavy biodegradation of hydrocarbon molecules, supported by the depletion of light n-alkanes and other labile compounds. This advanced asphalt biodegradation is the likely reason for the absence of chemosynthetic communities at these seep sites.

Contralateral posterior interhemispheric approach to deep medial parietooccipital vascular malformations: surgical technique and results.

PubMed

Burkhardt, Jan-Karl; Winkler, Ethan A; Lawton, Michael T

2017-07-21

OBJECTIVE Deep medial parietooccipital arteriovenous malformations (AVMs) and cerebral cavernous malformations (CCMs) are traditionally resected through an ipsilateral posterior interhemispheric approach (IPIA), which creates a deep, perpendicular perspective with limited access to the lateral margins of the lesion. The contralateral posterior interhemispheric approach (CPIA) flips the positioning, with the midline positioned horizontally for retraction due to gravity, but with the AVM on the upper side and the approach from the contralateral, lower side. The aim of this paper was to analyze whether the perpendicular angle of attack that is used in IPIA would convert to a parallel angle of attack with the CPIA, with less retraction, improved working angles, and no significant increase in risk. METHODS A retrospective review of pre- and postoperative clinical and radiographic data was performed in 8 patients who underwent a CPIA. RESULTS Three AVMs and 5 CCMs were resected using the CPIA, with an average nidus size of 2.3 cm and CCM diameter of 1.7 cm. All lesions were resected completely, as confirmed on postoperative catheter angiography or MRI. All patients had good neurological outcomes, with either stable or improved modified Rankin Scale scores at last follow-up. CONCLUSIONS The CPIA is a safe alternative approach to the IPIA for deep medial parietooccipital vascular malformations that extend 2 cm or more off the midline. Contralaterality and retraction due to gravity optimize the interhemispheric corridor, the surgical trajectory to the lesion, and the visualization of the lateral margin, without resection or retraction of adjacent normal cortex. Although the falx is a physical barrier to accessing the lesion, it stabilizes the ipsilateral hemisphere while gravity delivers the dissected lesion through the transfalcine window. Patient positioning, CSF drainage, venous preservation, and meticulous dissection of the deep margins are critical to the safety of this approach.

Towards a model-based understanding of the Mediterranean circulation during the Messinian Salinity Crisis

NASA Astrophysics Data System (ADS)

Simon, Dirk; Meijer, Paul

2016-04-01

Today, the Atlantic-Mediterranean gateway (the Strait of Gibraltar) and the strong evaporative loss in the east let the Mediterranean Sea attain a salinity of 2-3 g/l higher than the Atlantic Ocean. During the winter months, strong cooling of surface waters in the north forms deep water, which mixes the Mediterranean, while during summer the water column is stratified. During the Messinian Salinity Crisis (MSC, 5.97-5.33Ma) the salt concentration was high enough to reach the saturation of gypsum (~130-160 g/l) and halite (~350 g/l). This caused large deposits of these evaporites all over the basin, capturing 6% of the World Ocean salt within the Mediterranean at the time. Although several mechanisms have been proposed as to how the Mediterranean circulation might have functioned, these mechanisms have yet to be rooted in physics and tested quantitatively. Understanding circulation during the MSC becomes particularly important when comparing Mediterranean marginal to deep basins. On the one hand, many of the marginal basins in the Mediterranean are well studied, like the Sorbas basin (Spain) or the Vena del Gesso basin (Italy). On the other hand, the deep Mediterranean is less well studied, as no full record of the whole deep sequence exists. This makes it very complicated to correlate marginal and deep basin records. Here we are presenting the first steps in working towards a physics-based understanding of the mixing and stratification bahaviour of the Mediterranean Sea during the MSC. The final goal is to identify the physical mechanism needed to form such a salt brine and to understand how it differs from today's situation. We are hoping to compare our results to, and learn from, the much smaller but best available analog to the MSC, the Dead Sea, where recent overturning has been documented.

Boundary scavenging in the Pacific Ocean - A comparison of Be-10 and Pa-231

NASA Technical Reports Server (NTRS)

Anderson, R. F.; Lao, Y.; Broecker, W. S.; Trumbore, S. E.; Hofmann, H. J.

1990-01-01

Measurements of U, Th, Pa-231, and Be-10 concentrations were conducted in Holocene sediments from several sites representing open-ocean and ocean-margin environments in the Pacific Ocean. The results show that boundary scavenging plays a major role in the removal of Be-10 from the Pacific. Deposition of Be-10 is more than an order of magnitude greater at margin sites than at deep central Pacific sites, while Pa-231 is 4- to 5-fold greater at margin sites. The factors controling boundary scavenging of Pa and Be are discussed.

Water Security and Hydropolitics of the Nile River: South Sudan’s National Security in the 21st Century

DTIC Science & Technology

2011-12-16

Politics of the Nile Basin” (Master’s Thesis, University of Witwatersrand, Johannesburg, 2009). 2 While the Nile Basin is the longest trans- boundary ...conflicts, there may be an area of cooperation among states that share trans- boundary international river systems.32 Other staggering statistics on the...

Deep-Sea Drilling.

ERIC Educational Resources Information Center

White, Stan M.

1979-01-01

Drilling during 1978 focused on three major geologic problems: the nature and origin of the oceanic crust, the nature and geologic history of the active continental margins, and the oceanic paleoenvironment. (Author/BB)

Sediment delivery to the Gulf of Alaska: source mechanisms along a glaciated transform margin

USGS Publications Warehouse

Dobson, M.R.; O'Leary, D.; Veart, M.

1998-01-01

Sediment delivery to the Gulf of Alaska occurs via four areally extensive deep-water fans, sourced from grounded tidewater glaciers. During periods of climatic cooling, glaciers cross a narrow shelf and discharge sediment down the continental slope. Because the coastal terrain is dominated by fjords and a narrow, high-relief Pacific watershed, deposition is dominated by channellized point-source fan accumulations, the volumes of which are primarily a function of climate. The sediment distribution is modified by a long-term tectonic translation of the Pacific plate to the north along the transform margin. As a result, the deep-water fans are gradually moved away from the climatically controlled point sources. Sets of abandoned channels record the effect of translation during the Plio-Pleistocene.

Deep Reading, Cost/Benefit, and the Construction of Meaning: Enhancing Reading Comprehension and Deep Learning in Sociology Courses

ERIC Educational Resources Information Center

Roberts, Judith C.; Roberts, Keith A.

2008-01-01

Reading comprehension skill is often assumed by sociology instructors, yet many college students seem to have marginal reading comprehension skills, which may explain why fewer than half of them are actually doing the reading. Sanctions that force students to either read or to pay a price are based on a rational choice model of behavior--a…

Origin of the Sinai-Negev erg, Egypt and Israel: mineralogical and geochemical evidence for the importance of the Nile and sea level history

USGS Publications Warehouse

Muhs, Daniel R.; Roskin, Joel; Tsoar, Haim; Skipp, Gary; Budahn, James R.; Sneh, Amihai; Porat, Naomi; Stanley, Jean-Daniel; Katra, Itzhak; Blumberg, Dan G.

2013-01-01

The Sinai–Negev erg occupies an area of 13,000 km2 in the deserts of Egypt and Israel. Aeolian sand of this erg has been proposed to be derived from the Nile Delta, but empirical data supporting this view are lacking. An alternative source sediment is sand from the large Wadi El Arish drainage system in central and northern Sinai. Mineralogy of the Negev and Sinai dunes shows that they are high in quartz, with much smaller amounts of K-feldspar and plagioclase. Both Nile Delta sands and Sinai wadi sands, upstream of the dunes, also have high amounts of quartz relative to K-feldspar and plagioclase. However, Sinai wadi sands have abundant calcite, whereas Nile Delta sands have little or no calcite. Overall, the mineralogical data suggest that the dunes are derived dominantly from the Nile Delta, with Sinai wadi sands being a minor contributor. Geochemical data that proxy for both the light mineral fraction (SiO2/10–Al2O3 + Na2O + K2O–CaO) and heavy mineral fraction (Fe2O3–MgO–TiO2) also indicate a dominant Nile Delta source for the dunes. Thus, we report here the first empirical evidence that the Sinai–Negev dunes are derived dominantly from the Nile Delta. Linkage of the Sinai–Negev erg to the Nile Delta as a source is consistent with the distribution of OSL ages of Negev dunes in recent studies. Stratigraphic studies show that during the Last Glacial period, when dune incursions in the Sinai–Negev erg began, what is now the Nile Delta area was characterized by a broad, sandy, minimally vegetated plain, with seasonally dry anastomosing channels. Such conditions were ideal for providing a ready source of sand for aeolian transport under what were probably much stronger glacial-age winds. With the post-glacial rise in sea level, the Nile River began to aggrade. Post-glacial sedimentation has been dominated by fine-grained silts and clays. Thus, sea level, along with favorable climatic conditions, emerges as a major influence on the timing of dune activity in the Sinai–Negev erg, through its control on the supply of sand from the Nile Delta. The mineralogy of the Sinai–Negev dunes is also consistent with a proposed hypothesis that these sediments are an important source of loess in Israel.

Development of live attenuated Streptococcus agalactiae as potential vaccines by selecting for resistance to sparfloxacin.

PubMed

Pridgeon, Julia W; Klesius, Phillip H

2013-05-31

To develop attenuated bacteria as potential live vaccines, sparfloxacin was used in this study to modify 40 isolates of Streptococcus agalactiae. Majority of S. agalactiae used in this study were able to develop at least 80-fold resistance to sparfloxacin. When the virulence of the sparfloxacin-resistant S. agalactiae isolates were tested in 10-12g Nile tilapia by intraperitoneal injection at dose of 2×10(7)CFU/fish, 31 were found to be avirulent to fish. Of the 31 avirulent sparfloxacin-resistant S. agalactiae isolates, 30 provided 75-100% protection to 10-12g Nile tilapia against challenges with a virulent S. agalactiae isolate Sag 50. When the virulence of the 30 sparfloxacin-resistant S. agalactiae isolates was tested in 3-5g Nile tilapia by intraperitoneal injection at dose of 2×10(7)CFU/fish, six were found to be avirulent to 3-5g Nile tilapia. Of the six avirulent sparfloxacin-resistant S. agalactiae isolates, four provided 3-5g Nile tilapia 100% protection against challenges with homologous isolates, including Sag 97-spar isolate that was non-hemolytic. However, Sag 97-spar failed to provide broad cross-protection against challenges with heterologous isolates. When Nile tilapia was vaccinated with a polyvalent vaccine consisting of 30 sparfloxacin-resistant S. agalactiae isolates at dose of 2×10(6)CFU/fish, the polyvalent vaccine provided significant (P<0.001) protection to both 3-5g and 15-20g Nile tilapia against challenges with 30 parent isolates of S. agalactiae. Taken together, our results suggest that a polyvalent vaccine consisting of various strains of S. agalactiae might be essential to provide broader protection to Nile tilapia against infections caused by S. agalactiae. Published by Elsevier Ltd.

West Nile virus disease: a descriptive study of 228 patients hospitalized in a 4-county region of Colorado in 2003.

PubMed

Bode, Amy V; Sejvar, James J; Pape, W John; Campbell, Grant L; Marfin, Anthony A

2006-05-01

Risk factors for complications of West Nile virus disease and prognosis in hospitalized patients are incompletely understood. Demographic characteristics and data regarding potential risk factors, hospitalization, and dispositions were abstracted from medical records for residents of 4 Colorado counties who were hospitalized in 2003 with West Nile virus disease. Univariate and multivariate analyses were used to identify factors associated with West Nile encephalitis (WNE), limb weakness, or death by comparing factors among persons with the outcome of interest with factors among those without the outcome of interest. Medical records of 221 patients were reviewed; 103 had West Nile meningitis, 65 had WNE, and 53 had West Nile fever. Respiratory failure, limb weakness, and cardiac arrhythmia occurred in all groups, with significantly more cases of each in the WNE group. Age, alcohol abuse, and diabetes were associated with WNE. Age and WNE were associated with limb weakness. The mortality rate in the WNE group was 18%; age, immunosuppression, requirement of mechanical ventilation, and history of stroke were associated with death. Only 21% of patients with WNE who survived returned to a prehospitalization level of function. The estimated incidence of West Nile fever cases that required hospitalization was 6.0 cases per 100,000 persons; West Nile fever was associated with arrhythmia, limb weakness, and respiratory failure. Persons with diabetes and a reported history of alcohol abuse and older persons appear to be at increased risk of developing WNE. Patients with WNE who have a history of stroke, who require mechanical ventilation, or who are immunosuppressed appear to be more likely to die. Respiratory failure, limb weakness, and arrhythmia occurred in all 3 categories, but there were significantly more cases of all in the WNE group.

Deep structure of the Texas Gulf passive margin and its Ouachita-Precambrian basement: Results of the COCORP San Marcos arch survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Culotta, R.; Latham, T.; Oliver, J.

1992-02-01

This COCORP deep seismic survey provides a comprehensive image of the southeast-Texas part of the Gulf passive margin and its accreted Ouachita arc foundation. Beneath the updip limit of the Cenozoic sediment wedge, a prominent antiformal structure is imaged within the interior zone of the buried late Paleozoic Ouachita orogen. The structure appears to involve Precambrian Grenville basement. The crest of the antiform is coincident with the Cretaceous-Tertiary Luling-Mexia-Talco fault zone. Some of these faults dip to the northwest, counter to the general regional pattern of down-to-the-basin faulting, and appear to sole into the top of the antiform, suggesting thatmore » the Ouachita structure has been reactivated as a hingeline to the subsiding passive margin. The antiform may be tied via this fault system and the Ouachita gravity gradient to the similar Devils River, Waco, and Benton uplifts, interpreted as Precambrian basement-cored massifs. Above the Paleozoic sequence, a possible rift-related graben is imaged near the updip limit of Jurassic salt. Paleoshelf edges of the major Tertiary depositional sequences are marked by expanded sections disrupted by growth faults and shale diapirs. Within the Wilcox Formation, the transect crosses the mouth of the 900-m-deep Yoakum Canyon, a principal pathway of sediment delivery from the Laramide belt to the Gulf. Beneath the Wilcox, the Comanchean (Lower Cretaceous) shelf edge, capped by the Stuart City reef, is imaged as a pronounced topographic break onlapped by several moundy sediment packages. Because this segment of the line parallels strike, the topographic break may be interpreted as a 2,000-m-deep embayment in the Cretaceous shelf-edge, and possibly a major submarine canyon older and deeper than the Yoakum Canyon.« less

(Tele)presenting Secrets from the Deep Southern California Margin

NASA Astrophysics Data System (ADS)

Levin, L. A.; Girguis, P. R.; Brennan, M.; German, C. R.; Raineault, N.; Le, J. T.; Grupe, B.; Gallo, N.; Inderbitzen, K. E.; Tuzun, S.; Wagner, J.

2016-02-01

This past summer scientists, students and the public participated through telepresence in 2 weeks of deep-sea exploration via the EV Nautilus, visiting a tremendous diversity of sites found along the southern California continental margin (200-900m). We observed previously unknown cold seeps; new and unexpected assemblages and species distributions; and novel animal behaviors; all under the overarching influence of strong oxygen gradients from the East Pacific oxygen minimum zone (OMZ). The expedition discovered four new methane seep sites, each with distinct biota reflecting varying depth and oxygen levels. OMZ specialists such as lucinid clams, hagfish, and thornyhead fishes coexisted with seep biota (vesicoymid clams) at a 1.4-km long seep off Point Dume (Malibu, CA), forming a blended ecosystem with distinct zonation. A range of habitats (canyons, knolls, mounds) within the OMZ hosted fish, crustacean, echinoderm and cnidarian species with unusual hypoxia tolerance to < 3 µM O2 or lower. Organic falls (a sunken whale and naturally occurring kelp holdfasts) hosted many invertebrates and served as clear magnets for scavengers and predators. In situ observations revealed unusual behaviors including "parasailing" snails and drifting benthic siphonophores in the Santa Monica Basin, fish aggregating at seep carbonates, and cruising catsharks and their egg cases at methane seeps. Many of these observations advance understanding of the ecosystem services provided by deep-sea, margin habitats, while stimulating public interest in ocean exploration. Telepresence permitted broad engagement of students and scientists from as near as Los Angeles and as far as South Africa, as well as meaningful interactions with the public. In situ exploration and observation can and will play increasingly important roles in environmental management of the deep ocean as disturbance from resource extraction and climate change intensify.

West Nile Virus Infection in Sheep.

PubMed

Rimoldi, G; Mete, A; Adaska, J M; Anderson, M L; Symmes, K P; Diab, S

2017-01-01

West Nile virus (WNV) infection has been detected in many species of birds and mammals, but scant information is available about the disease in small ruminants. West Nile virus was diagnosed in 6 sheep with neurological signs and encephalitis, in California between 2002 and 2014. All sheep had severe lymphoplasmacytic meningoencephalitis. Lymphoplasmacytic myelitis was also detected in 2 sheep where the spinal cord was examined. Brain tissue was positive for WNV detected by polymerase chain reaction in 6 of 6 sheep and by immunohistochemistry (IHC) in 5 of 6 sheep. Viral antigen was not detected by IHC in extraneural tissues in the 3 sheep examined. West Nile virus RNA was sequenced from 2 of 6 sheep, and each one clusters closely with WNV isolated from mosquito pools from nearby locations at similar times. West Nile virus was the most common cause of viral encephalitis in sheep diagnosed at this laboratory between 2002 and 2014, accounting for 6 of 9 sheep.

Nile Delta exhibited a spatial reversal in the rates of shoreline retreat on the Rosetta promontory comparing pre- and post-beach protection

NASA Astrophysics Data System (ADS)

Ghoneim, Eman; Mashaly, Jehan; Gamble, Douglas; Halls, Joanne; AbuBakr, Mostafa

2015-01-01

The coastline of the Nile Delta experienced accelerated erosion since the construction of the Aswan High Dam in 1964 and, consequently, the entrapment of a large amount of river sediments behind it. The coastline of the Rosetta promontory showed the highest erosion in the Delta with an average retreat rate of 137.4 m year- 1. In 1991, in an effort to mitigate sediment loss, a 4.85 km long seawall was built on the outer margin of the promontory. For additional beach protection, 15 groins were constructed along the eastern and western sides of the seawall in 2003 and 2005. To quantify erosion and accretion patterns along the Rosetta promontory, 11 Landsat images acquired at unequal intervals during a 40 year time span (1972 and 2012) were analyzed. The positions of shorelines were automatically extracted from satellite imagery and compared with three very high resolution QuickBird and WorldView2 images for data validation. Analysis of the rates of shoreline change revealed that the construction of the seawall was largely successful in halting the recession along the tip of the promontory, which lost 10.8 km2 prior to coastal protection. Conversely, the construction of the 15 groins has negatively affected the coastal morphology of the promontory and caused a reversal from accretion to fast erosion along the promontory leeside, where some segments of the shoreline have undergone as much as 30.8 m year- 1 of erosion. Without hard structures, the tip of the Rosetta promontory would have retreated 2.3 km by 2013 and lost 7.2 km2 of land. About 10% of this land is deltaic fertile cultivated farms. Moreover, without additional protection the sides of the promontory will lose about 1.3 km2 of land and the coastline would recede at an average rate of 200 m by 2020. Unless action is taken, coastal erosion, enhanced by rising sea level, will steadily eat away the Nile Delta at an alarming rate. The successful demonstration of the advocated procedures in this study could be adopted, with appropriate modifications, for other deltas worldwide.

Geophysical evidence for a transform margin in Northwestern Algeria: possible vestige of a Subduction-Transform Edge Propagator

NASA Astrophysics Data System (ADS)

Badji, R.; Charvis, P.; Bracene, R.; Galve, A.; Badsi, M.; Ribodetti, A.; Benaissa, Z.; Klingelhoefer, F.; Medaouri, M.; Beslier, M.

2013-12-01

This work is part of the Algerian-French SPIRAL program (Sismique Profonde et Investigation Régionale du Nord de l'Algérie) which provides unprecedented images of the deep structure of the western Algerian Margin based on several wide-angle and multichannel seismic data shot across the Algerian Margin. One of the different hypotheses for the opening of the western Mediterranean Sea, we are testing is that the western part of the Algerian margin was possibly part of the southern edge of the Alboran continental block during its westward migration related to the rollback of the Betic-Rif-Alboran subduction zone. A tomographic inversion of the first arrival traveltimes along a 100-km long wide-angle seismic profile shot over 40 Ocean Bottom Seismometers, across the Margin offshore Mostaganem (Northwestern Algerian Margin) was conducted. The final model reveals striking feature in the deep structure of the margin from north to south: 1- the oceanic crust is as thin as 4-km, with velocities ranging from 5.0 to 7.1 km/s, covered by a 3.3 km thick sedimentary pile (seismic velocities from 1.5 to 5.0 km/s) characterized by an intense diapiric activity of the Messinian salt layer. 2- a sharp transition zone, less than 10 km wide, with seismic velocities intermediate between oceanic seismic velocities (observed northward) and continental seismic velocities (observed southward). This zone coincides with narrow and elongated pull apart basins imaged by multichannel seismic data. No evidence of volcanism nor of exhumed serpentinized upper mantle as described along many extensional continental margins are observed along this segment of the margin. 3- a thinned continental crust coincident with a rapid variation of the Moho depth imaged from 12 to ~20 km with a dip up to 50%. The seafloor bathymetry is showing a steep continental slope (>20%). Either normal or inverse faults are observed along MCS lines shot in the dip direction but they do not present large vertical displacement and could be related primarily to strike slip motion. These results support the hypothesis, that the margin offshore Mostaganem is not an extensional margin but rather a transform margin. There is little evidence of tectonic inversion as described eastward along the Kabylian Margin. Possibly strike slip motion affected the thinned continental crust and the transition zone suggesting that this margin is a vestige of the Subduction-Transform Edge Propagator (STEP) related to the westward migration of the Alboran block.

Structure of the North American Atlantic Continental Margin

USGS Publications Warehouse

Schlee, J.S.; Klitgord, K.K.

1986-01-01

Off E N America, where the structure of the continental margin is essentially constructional, seismic profiles have approximated geologic cross sections up to 10-15km below the sea floor and revealed major structural and stratigraphic features that have regional hydrocarbon potential. These features include a) a block-faulted basement hinge zone; b) a deep, broad, rifted basement filled with clastic sediment and salt; and c) a buried paleoshelf-edge complex that has many forms. The mapping of seismostratigraphic units over the continental shelf, slope, and rise has shown that the margin's developmental state included infilling of a rifted margin, buildup of a carbonate platform, and construction of an onlapping continental-rise wedge that was accompanied by erosion of the slope. -from Authors

Retinyl palmitate flexible polymeric nanocapsules: characterization and permeation studies.

PubMed

Teixeira, Zaine; Zanchetta, Beatriz; Melo, Bruna A G; Oliveira, Luciana L; Santana, Maria H A; Paredes-Gamero, Edgar J; Justo, Giselle Z; Nader, Helena B; Guterres, Sílvia S; Durán, Nelson

2010-11-01

Polymeric nanocapsules with elastic characteristics were prepared by the pre-formed polymer interfacial deposition method. The system consists of an oily core of retinyl palmitate with Span 60 and a polymeric wall of poly(D,L-lactide) (PLA). A narrow size distribution (215 nm, P.D.I. 0.10) was showed by dynamic light scattering (DLS) analyses. Particle deformability was observed by transmission electron microscopy (TEM) images and permeation of the particles through two superposed membranes of smaller pore diameters. Permeation studies were achieved using plastic surgery abdominal human skin by Franz diffusion cell. Retinyl palmitate permeates into deep skin layers. Besides, a PLA fluorescent derivative conjugated with Nile blue dye by an amide covalent bound was additionally obtained. Permeation profile of the nanocapsules with the fluorescent polymer was evaluated by confocal laser scanning microscopy (CLSM). The CLSM showed that nanocapsules were distributed uniformly, suggesting that the permeation mechanism through skin is intercellular. Thus, the use of these nanocapsules may be a feasible strategy to enhance the permeation of actives into the skin when delivery to deep layers is aimed. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Tension zones of deep-seated rockslides revealed by thermal anomalies and airborne laser scan data

NASA Astrophysics Data System (ADS)

Baroň, Ivo; Bečkovský, David; Gajdošík, Juraj; Opálka, Filip; Plan, Lukas; Winkler, Gerhard

2015-04-01

Open cracks, tension fractures and crevice caves are important diagnostic features of gravitationally deformed slopes. When the cracks on the upper part of the slope open to the ground surface, they transfer relatively warm and buoyant air from the underground in cold seasons and thus could be detected by the infrared thermography (IRT) as warmer anomalies. Here we present two IRT surveys of deep-seated rockslides in Austria and the Czech Republic. We used thermal imaging cameras Flir and Optris, manipulated manually from the ground surface and also from unmanned aerial vehicle and piloted ultralight-plane platforms. The surveys were conducted during cold days of winter 2014/2015 and early in the morning to avoid the negative effect of direct sunshine. The first study site is the Bad Fischau rockslide in the southern part of the Vienna Basin (Austria). It was firstly identified by the morphostructural analysis of 1-m digital terrain model from the airborne laser scan data. The rockslide is superimposed on, and closely related to the active marginal faults of the Vienna basin, which is a pull apart structure. There is the 80-m-deep Eisenstein Show Cave situated in the southern lateral margin of the rockslide. The cave was originally considered to be purely of hydrothermal (hypogene) karstification; however its specific morphology and position within the detachment zone of the rockslide suggests its relation to gravitational slope-failure. The IRT survey revealed the Eisenstein Cave at the ground surface and also several other open cracks and possible cleft caves along the margins, headscarp, and also within the body of the rockslide. The second surveyed site was the Kněhyně rockslide in the flysch belt of the Outer Western Carpathians in the eastern Czech Republic. This deep-seated translational rockslide formed about eight known pseudokarst crevice caves, which reach up to 57 m in depth. The IRT survey recognized several warm anomalies indicating very deep deformation of the slope. When compared to digital terain model, some of these thermal anomalies suggest large unexplored crack systems deep in the rock-slope failure. As a conclusion we notice that especially when compared to topographic structures visualized on high accuracy digital terrain models, detecting the thermal anomalies could significantly contribute to understanding the subsurface occurrence of the tension fractures and voids within deep-seated rockslide bodies.

West Nile Virus Infection among Humans, Texas, USA, 2002–2011

PubMed Central

Nolan, Melissa S.; Schuermann, Jim

2013-01-01

We conducted an epidemiologic analysis to document West Nile virus infections among humans in Texas, USA, during 2002–2011. West Nile virus has become endemic to Texas; the number of reported cases increased every 3 years. Risk for infection was greatest in rural northwestern Texas, where Culex tarsalis mosquitoes are the predominant mosquito species. PMID:23260575

Earth view over Egypt and the Nile River taken during STS-121

NASA Image and Video Library

2006-07-04

STS121-334-026 (4-17 July 2006) --- This photo, featuring an easterly view of the Nile River, the Nile River Delta, Sinai Peninsula, the Suez Canal, Red Sea and part of the Mediterranean Sea, was taken by one of the STS-121 crewmembers aboard the Space Shuttle Discovery. Cairo, Egypt, can be seen at far right.

Holocene alluvial history and archaeological significance of the Nile floodplain in the Saqqara-Memphis region, Egypt

NASA Astrophysics Data System (ADS)

Hassan, F. A.; Hamdan, M. A.; Flower, R. J.; Shallaly, N. A.; Ebrahem, E.

2017-11-01

A suite of drill cores undertaken on the Saqqara-Memphisfloodplain revealed an array of Late Pleistocene-Holocene sediment facies that show a complex of spatio-temporal changes in sediment related to migration of the River Nile, Nile flood variations, settlement sites and climate change. The recovered data enhance our understanding of the history of the modern River Nile and its relationship to the emergence and continuity of Egyptian civilization. The floodplain of the Saqqara-Memphis area reveals a sequence of aggradation and degradation events comprising six clearly marked sedimentary units (I-VI), overlying Late Pleistocene fluvial sand and gravel (unit I). Deposition of unit II resumed during a period of high Nile flow, rapid sea level rise and locally wet climatic conditions. As a result, the floodplain was occupied by swamps and anastomosing channels. Subsequently, the Nile changed to a more stable meandering channel system with well-developed levees and flood basins (unit III). This aggradation unit was subsequently eroded by the end of Old Kingdom (ca. 4.2 kyr cal BP). The degradation hiatus was followed by a widespread layer of alluvial silt and sand indicating very high Nile floods that coincide with historical records of very high floods during the Middle Kingdom and frequently high floods during the New Kingdom (unit IV). During the last two thousand years (units VI-VII) floods generally diminished except for several notable lows and highs. Our calculations of the long-term rate of siltation during the Middle and Late Holocene suggest an average rate of 0.235 m/century rather than the commonly cited 0.09-0.12 m per century. In addition, our study of satellite imagery of the Memphite region in the context of archaeological data combined with our own geological studies reveal that the main Nile in Neolithic and Predynastic times (ca.7.0-5.0 kyr cal BP) ran along the eastern edge of the current floodplain. A lateral branch of the Nile ran along the western edge of the floodplain. It is on the bank of this branch that the first capital of a unified Egypt was established. Our cores also reveal during the Dynastic period, the western branch shifted eastwards, while the main Nile shifted westwards.

Organic Geochemistry of Sediments, Interstitial Fluids and Light Volatile Hydrocarbon Gases from Giza and North Alex Mud Volcanoes, Western Nile Deep-Sea Fan

NASA Astrophysics Data System (ADS)

Nuzzo, Marianne; Elvert, Marcus; Heuer, Verena; Schmidt, Mark; Hinrichs, Kai-Uwe; Scholz, Florian; Reitz, Anja; Hensen, Christian

2010-05-01

The West Nile Delta Project is a multi-disciplinary research project lead at IFM-GEOMAR (Kiel, Germany) and funded by RWE-DEA (Hamburg, Germany). It aims at investigating the sources and transport mechanisms of fluids and hydrocarbon gases seeping at two mud volcanoes (MVs) of the western Nile Deep-Sea Fan: North Alex and Giza MVs, and at the long-term monitoring of the seepage activity at these sites [1,2]. A comparative study of the organic geochemistry of sediments, gases and fluids was carried out in order to constrain (i) the sources of fluids, mud and gases erupted at these cold seeps, and (ii) the microbial hydrocarbon-oxidation processes associated with the extrusion of mud and gases. The molecular and stable isotope composition of light volatile hydrocarbon gases stripped from pore fluids reveal a clear thermogenic origin at the less active Giza MV and at the active centre of N. Alex MV. However, they probably originate from different sources, as shown by the distinct 13C-CH4 values of ~ -45‰ and -37‰VPDB at North Alex and Giza MVs, respectively, while 2H-CH4 values are similar (~ -228‰VSMOW). Away from the centre at North Alex MV the gases have variable compositions and are mainly produced by Archaea microbes. The microbial production of CH4 is probably sustained by the high content of the mud breccia sediments in labile organic matter. Indeed Total Organic Carbon content values are high (~ 1 and 2%weight) in MV sediments from both sites as well as at the reference site away from Giza MV, suggesting a main shallow (Plio-Pleistocene) sedimentary source. Consistently, the sedimentary lipids contain high amounts of compounds typically issued from terrestrial plants such as -amyrin and nC26:0 to nC30:0 fatty acids & alkenols. The hypothesis that labile terrestrial organic matter sustains intense microbial activity in the mud volcano sediments is supported by the extreme enrichment of pore fluids in a suite of Volatile Fatty Acids, in particular in acetic acid with values as high as 1 to 2mM at and near the centre of N. Alex MV. Additionally, the lipids extracted from MV sediments contain long-chain n-alkanes and biomarker compounds typically related to the presence of petroleum or bitumen as well as compounds associated with microbial communities living from the Anaerobic Oxidation of Methane. A large variety of these compounds have however been observed at the MVs, and their concentrations are quite variable as well. Here we present the results of multivariate statistical analyses applied to an extensive data set. Complementarily, Compound-Specific-Isotope-Analysis techniques have been used to study the origin of pore water Volatile Fatty Acids and of selected lipid biomarkers at Giza and North Alex MVs. Last, the information provided by geophysical imaging and heat flux measurements performed in the context of the West Nile Delta Project [1] has been taken into account to interpret the complex biogeochemical processes taking place at the MVs. [1] Feseker et al. (2008) RV Poseidon cruise report ISSN 1614-6298, IFM-GEOMAR, Kiel (Germany). [2] Bialas & Brϋckmann (2008) RV Pelagia 64PE298 WND Project cruise report, IFM-GEOMAR, Kiel (Germany), 52p.

Mutually beneficial and sustainable management of Ethiopian and Egyptian dams in the Nile Basin

NASA Astrophysics Data System (ADS)

Habteyes, Befekadu G.; Hasseen El-bardisy, Harb A. E.; Amer, Saud A.; Schneider, Verne R.; Ward, Frank A.

2015-10-01

Ongoing pressures from population growth, recurrent drought, climate, urbanization and industrialization in the Nile Basin raise the importance of finding viable measures to adapt to these stresses. Four tributaries of the Eastern Nile Basin contribute to supplies: the Blue Nile (56%), White Nile-Albert (14%), Atbara (15%) and Sobat (15%). Despite much peer reviewed work addressing conflicts on the Nile, none to date has quantitatively examined opportunities for discovering benefit sharing measures that could protect negative impacts on downstream water users resulting from new upstream water storage developments. The contribution of this paper is to examine the potential for mutually beneficial and sustainable benefit sharing measures from the development and operation of the Grand Ethiopian Renaissance Dam while protecting baseline flows to the downstream countries including flows into the Egyptian High Aswan Dam. An integrated approach is formulated to bring the hydrology, economics and institutions of the region into a unified framework for policy analysis. A dynamic optimization model is developed and applied to identify the opportunities for Pareto Improving measures to operate these two dams for the four Eastern Nile Basin countries: Ethiopia, South Sudan, Sudan, and Egypt. Results indicate a possibility for one country to be better off (Ethiopia) and no country to be worse off from a managed operation of these two storage facilities. Still, despite the optimism of our results, considerable diplomatic negotiation among the four riparians will be required to turn potential gains into actual welfare improvements.

Clinical and pathologic features of West Nile virus infection in native North American owls (Family strigidae).

PubMed

Fitzgerald, S D; Patterson, J S; Kiupel, M; Simmons, H A; Grimes, S D; Sarver, C F; Fulton, R M; Steficek, B A; Cooley, T M; Massey, J P; Sikarskie, J G

2003-01-01

Since the initial report of West Nile virus in the northeastern United States in 1999, the virus has spread rapidly westward and southward across the country. In the summer of 2002, several midwestern states reported increased cases of neurologic disease and mortality associated with West Nile virus infection in various native North American owl species. This report summarizes the clinical and pathologic findings for 13 captive and free-ranging owls. Affected species were all in the family Strigidae and included seven snowy owls (Nyctea scandiaca), four great-horned owls (Bubo virginianus), a barred owl (Strix varia), and a short-eared owl (Asio flammeus). Neurologic signs identified included head tilt, uncoordinated flight, paralysis, tremors, and seizures. Owls that died were screened for flaviviral proteins by immunohistochemical staining of formalin-fixed tissues, followed by specific polymerase chain reaction assay to confirm West Nile virus with fresh tissues when available. Microscopic lesions were widespread, involving brain, heart, liver, kidney, and spleen, and were typically nonsuppurative with infiltration by predominantly lymphocytes and plasma cells. Lesions in owls were much more severe than those previously reported in corvids such as crows, which are considered highly susceptible to infection and are routinely used as sentinel species for monitoring for the presence and spread of West Nile virus. This report is the first detailed description of the pathology of West Nile virus infection in Strigiformes and indicates that this bird family is susceptible to natural infection with West Nile virus.

Preliminary results of layered modelling of seismic refraction data at the East Limpopo Margin, Mozambique (PAMELA project, MOZ3/5 cruise)

NASA Astrophysics Data System (ADS)

Watremez, Louise; Evain, Mikael; Leprêtre, Angélique; Verrier, Fanny; Aslanian, Daniel; Leroy, Sylvie; Dias, Nuno; Afilhado, Alexandra; Schnurle, Philippe; d'Acremont, Elia; de Clarens, Philippe; Castilla, Raymi; Moulin, Maryline

2017-04-01

The East Limpopo Margin is a continental margin located offshore southern Mozambique, in the Mozambique Channel. The southern Mozambique margin has not been studied much until now, but its formation is assumed to be the result of the separation of the African plate from the Antarctica plate. A new geophysical survey MOZ3/5 (February-April 2016; PAMELA project*) allowed the acquisition of seven wide-angle reflection and refraction seismic profiles across the southernmost Mozambique margin. In this work, we show the first results obtained from the layered modelling of an approximately 400 km long transect crossing the East Limpopo Margin and including information from 22 ocean-bottom seismometers and 18 land seismometers. The velocity model, compared to coincident seismic reflection data, allows to observe (1) the variations of seismic velocities together with the variations of reflectivity characteristics in the sediments, including the occurrence of some magmatism, (2) some deep features located below the acoustic basement and that can be related to the pre-to-syn-rift history of the margin, (3) the velocities and Moho depths in the different areas of the crust, from the thick continental crust to the clear oceanic crust (magnetic anomalies), helping to define the nature of the crust and the presence of magmatic features along the whole profile, and (4) some velocity information in the uppermost mantle. These results will allow us to (1) understand the deep structures of the East Limpopo Margin and to have better constraints on the formation of the margin, helping kinematic reconstructions, improving the quantification of the magmatism along this margin, and (2) improve the knowledge of both the thermal evolution of the sediments and the potential magmatic sources in the study area. *The PAMELA project (PAssive Margin Exploration Laboratories) is a scientific project led by Ifremer and TOTAL in collaboration with Université de Bretagne Occidentale, Université Rennes 1, Université Pierre and Marie Curie, CNRS and IFPEN. Moulin, M., Aslanian, D., et al 2016. PAMELA-MOZ03 cruise, RV Pourquoi pas ?, http://dx.doi.org/10.17600/16001600 Moulin, M., Evain, M., et al. 2016. PAMELA-MOZ05 cruise, RV Pourquoi pas ?, http://dx.doi.org/10.17600/16009500

New species of the giant deep-sea isopod genus Bathynomus (Crustacea, Isopoda, Cirolanidae) from Hainan Island, South China Sea.

PubMed

Kou, Qi; Chen, Jun; Li, Xinzheng; He, Lisheng; Wang, Yong

2017-07-01

Several specimens of the giant deep-sea isopod genus Bathynomus were collected by a deep-sea lander at a depth of 898 m near Hainan Island in the northern South China Sea. After careful examination, this material and the specimens collected from the Gulf of Aden, north-western Indian Ocean, previously reported as Bathynomus sp., were identified to be the same as a new species to the genus. Bathynomus jamesi sp. nov. can be distinguished from the congeners by: the distal margin of pleotelson with 11 or 13 short straight spines and central spine not bifid; uropodal endopod and exopod with distolateral corner slightly pronounced; clypeus with lateral margins concave; and antennal flagellum extending when extended posteriorly reaches the pereonite 3. In addition, Bathynomus jamesi sp. nov. is also supported by molecular analyses based on mitochondrial COI and 16S rRNA gene sequences. The distribution range of the new species includes the western Pacific and north-western Indian Ocean. © 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Opportunities for woody crop production using treated wastewater in Egypt. I. Afforestation strategies

Treesearch

Ronald S. Zalesny Jr.; John A. Stanturf; Steven R. Evett; Nabil F. Kandil; Christopher Soriano

2011-01-01

The Nile River provides nearly 97% of Egypt's freshwater supply. Egypt's share of Nile waters is fixed at 55.5 billion cubic meters annually. As a result, Egypt will not be able to meet increasing water demand using freshwater from the Nile and has been developing non-conventional wastewater reuse strategies to meet future demands. The USAID Mission in Cairo...

Lake Nasser on Nile River in Egypt as seen from the Apollo 7 spacecraft

NASA Image and Video Library

1968-10-12

Lake Nasser on the Nile River in southeastern United Arab Republic (Egypt) as seen from the Apollo 7 spacecraft during its 10th revolution of the earth. Photographed from an altitude of 130 nautical miles, at ground elapsed time of 14 hours and 56 minutes. Lake Nasser was created by the contruction of the Aswan Dam on the Nile.

Opportunities for woody crop production using treated wastewater in Egypt

Treesearch

Ronald S. Jr. Zalesny; Steven R. Evett; Nabil F. Kandil; Chris Soriano; John A. Stanturf

2009-01-01

The Nile River provides nearly 97% of Egypt’s freshwater supply. Egypt's share of Nile waters is allocated according to international treaty obligations and is fixed at 55.5 billion cubic meters annually. As a result, Egypt will not be able to meet increasing water demand using freshwater from the Nile and has been developing wastewater reuse strategies to meet...

Analysis of YouTube as a Source of Information for West Nile Virus Infection

PubMed Central

Dubey, Divyanshu; Amritphale, Amod; Sawhney, Anshudha; Dubey, Devashish; Srivastav, Nupur

2014-01-01

Introduction A major outbreak of West Nile Virus was seen last year in different parts of the United States. Adequate dissemination of correct information about the disease would have helped decrease its spread and the associated panic in the general population. In this study, we looked into the use of YouTube as a resource for providing information about West Nile Virus infection. Objective This study aims to identify and evaluate YouTube as resource for providing information on West Nile Virus infection to the general public. Methods YouTube was searched on November 25, 2012, using the keywords West Nile Virus epidemic, West Nile Virus infection, and West Nile Virus prevention for videos uploaded in the past 6 months containing relevant information about the disease. The videos were classified as useful, misleading, or as news updates based on the type of information contained. Total viewership, number of days since upload, total duration of videos, and source of upload were noted. Results A total of 106 videos with information on West Nile Virus infection were included in the study, with 79.24% having useful information about the disease. Among the useful videos, 51/84 (60.71%) had information on disease prevention, and 29/84 (34.52%) contained information on news and research updates. The majority of these videos were uploaded by individuals (54.6%) or news agencies (41.8 %). Healthcare agencies contributed only 3.4 % of the total videos. Even though the useful videos represented 72% of all videos, there was significantly higher total viewership and viewership per day for the non-useful videos (P<0.05). Conclusions YouTube may be a significant resource for dissemination of information on public health issues like West Nile virus infection and should be targeted by healthcare agencies for this use. The major drawback of this medium is lack of verification by authorized healthcare professionals before these videos are made available for viewing by the community. Hence, a strict caution should be exercised in obtaining the information from unauthorized videos posted on YouTube. PMID:24573700

Nerve growth factor-inducible large external (NILE) glycoprotein: studies of a central and peripheral neuronal marker.

PubMed

Salton, S R; Richter-Landsberg, C; Greene, L A; Shelanski, M L

1983-03-01

The PC12 clone of pheochromocytoma cells undergoes neuronal differentiation in the presence of nerve growth factor (NGF). Concomitant with this is a significant induction in the incorporation of radiolabeled fucose or glucosamine into a 230,000-dalton cell surface glycoprotein named the NGF-Inducible Large External, or NILE, glycoprotein (GP) (McGuire, J. C., L. A. Greene, and A. V. Furano (1978) Cell 15: 357-365). In the current studies NILE GP was purified from PC12 cells using wheat germ agglutinin-agarose affinity chromatography and SDS-polyacrylamide gel electrophoresis (PAGE). Polyclonal antisera were raised against purified NILE GP and were found to selectively immunoprecipitate a single 230,000-dalton protein from detergent extracts of PC12 cells metabolically labeled with either [3H]fucose, [3H]glucosamine, or [35S]methionine. These antisera stained the surfaces of PC12 cells by indirect immunofluorescence and were cytotoxic to PC12 cells in the presence of complement. Limited treatment of PC12 cells with either trypsin or pronase produced a fucosylated 90,000-dalton immunoreactive fragment of NILE GP which remained in the membrane. Using quantitative immunoelectrophoresis, the action of NGF on NILE GP was represent an increase in the amount of protein, rather than a selective increase in carbohydrate incorporation. Immunofluorescent staining of primary cell cultures and tissue whole mounts revealed that immunologically cross-reactive NILE GP appears to be expressed on the cell surfaces (somas and neurites) of most if not all peripheral and central neurons examined. Immunoprecipitation of radiolabeled cultures showed that the cross-reactive material had an apparent molecular weight by SDS-PAGE of 225,000 to 230,000 in the peripheral nervous system and 200,000 to 210,000 in the central nervous system. NILE-cross-reactive material was also found to a small extent on Schwann cell surfaces, but not at all on a variety of other cell types. These results suggest that immunoreactive NILE GP is distributed widely and selectively on neural cell surfaces.

Analysis of YouTube as a source of information for West Nile Virus infection.

PubMed

Dubey, Divyanshu; Amritphale, Amod; Sawhney, Anshudha; Dubey, Devashish; Srivastav, Nupur

2014-12-01

A major outbreak of West Nile Virus was seen last year in different parts of the United States. Adequate dissemination of correct information about the disease would have helped decrease its spread and the associated panic in the general population. In this study, we looked into the use of YouTube as a resource for providing information about West Nile Virus infection. This study aims to identify and evaluate YouTube as resource for providing information on West Nile Virus infection to the general public. YouTube was searched on November 25, 2012, using the keywords West Nile Virus epidemic, West Nile Virus infection, and West Nile Virus prevention for videos uploaded in the past 6 months containing relevant information about the disease. The videos were classified as useful, misleading, or as news updates based on the type of information contained. Total viewership, number of days since upload, total duration of videos, and source of upload were noted. A total of 106 videos with information on West Nile Virus infection were included in the study, with 79.24% having useful information about the disease. Among the useful videos, 51/84 (60.71%) had information on disease prevention, and 29/84 (34.52%) contained information on news and research updates. The majority of these videos were uploaded by individuals (54.6%) or news agencies (41.8 %). Healthcare agencies contributed only 3.4 % of the total videos. Even though the useful videos represented 72% of all videos, there was significantly higher total viewership and viewership per day for the non-useful videos (P<0.05). YouTube may be a significant resource for dissemination of information on public health issues like West Nile virus infection and should be targeted by healthcare agencies for this use. The major drawback of this medium is lack of verification by authorized healthcare professionals before these videos are made available for viewing by the community. Hence, a strict caution should be exercised in obtaining the information from unauthorized videos posted on YouTube. © 2013 Marshfield Clinic.

Nile Red Detection of Bacterial Hydrocarbons and Ketones in a High-Throughput Format

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pinzon, NM; Aukema, KG; Gralnick, JA

A method for use in high-throughput screening of bacteria for the production of long-chain hydrocarbons and ketones by monitoring fluorescent light emission in the presence of Nile red is described. Nile red has previously been used to screen for polyhydroxybutyrate (PHB) and fatty acid esters, but this is the first report of screening for recombinant bacteria making hydrocarbons or ketones. The microtiter plate assay was evaluated using wild-type and recombinant strains of Shewanella oneidensis and Escherichia coli expressing the enzyme OleA, previously shown to initiate hydrocarbon biosynthesis. The strains expressing exogenous Stenotrophomonas maltophilia oleA, with increased levels of ketone productionmore » as determined by gas chromatography-mass spectrometry, were distinguished with Nile red fluorescence. Confocal microscopy images of S. oneidensis oleA-expressing strains stained with Nile red were consistent with a membrane localization of the ketones. This differed from Nile red staining of bacterial PHB or algal lipid droplets that showed intracellular inclusion bodies. These results demonstrated the applicability of Nile red in a high-throughput technique for the detection of bacterial hydrocarbons and ketones. IMPORTANCE In recent years, there has been renewed interest in advanced biofuel sources such as bacterial hydrocarbon production. Previous studies used solvent extraction of bacterial cultures followed by gas chromatography-mass spectrometry (GC-MS) to detect and quantify ketones and hydrocarbons (Beller HR, Goh EB, Keasling JD, Appl. Environ. Microbiol. 76: 1212-1223, 2010; Sukovich DJ, Seffernick JL, Richman JE, Gralnick JA, Wackett LP, Appl. Environ. Microbiol. 76: 3850-3862, 2010). While these analyses are powerful and accurate, their labor-intensive nature makes them intractable to high-throughput screening; therefore, methods for rapid identification of bacterial strains that are overproducing hydrocarbons are needed. The use of high-throughput evaluation of bacterial and algal hydrophobic molecule production via Nile red fluorescence from lipids and esters was extended in this study to include hydrocarbons and ketones. This work demonstrated accurate, high-throughput detection of high-level bacterial long-chain ketone and hydrocarbon production by screening for increased fluorescence of the hydrophobic dye Nile red.« less

Impacts of West Nile Virus on wildlife

USGS Publications Warehouse

Saito, E.K.; Wild, M.A.

2004-01-01

The recent epidemic of West Nile virus in the United States proved to be unexpectedly active and was the largest epidemic of the virus ever recorded. Much remains to be discovered about the ecology and epidemiology of West Nile virus in the United States, including which species are important in maintaining the virus in nature, why some species are more susceptible to lethal infection, and what environmental factors are important in predicting future epidemics. These factors will likely vary regionally, depending on local ecological characteristics. Until scientists better understand the virus and factors influencing its activity, predicting its effects for future seasons is impossible. However, experts are certain about one thing: West Nile virus is here to stay.

West Nile Flavivirus Polioencephalomyelitis in a harbor seal (Phoca vitulina).

PubMed

Del Piero, F; Stremme, D W; Habecker, P L; Cantile, C

2006-01-01

A 12-year-old male harbor seal presented with progressive signs of neurologic dysfunction including head tremors, muzzle twitching, clonic spasms, and weakness. Lesions included polioencephalomyelitis with glial nodules, spheroids, neuronophagia, ring hemorrhages, and a few neutrophils. Neurons, fibers, and glial nodules were multifocally colonized with intracytoplasmic West Nile flavivirus antigens that were demonstrated using indirect immunohistochemical analysis. Flavivirus on cultured cells also was isolated and was identified by use of monoclonal antibodies and reverse transcriptase-polymerase chain reaction analysis. Clinical signs of disease and lesion morphology and distribution were similar to those of equine West Nile virus infection. Similar to horses, alpacas, humans, dogs, and reptiles, seals can be dead-end hosts of West Nile virus.

Deep Sea Drilling Project

ERIC Educational Resources Information Center

Kaneps, Ansis

1977-01-01

Discusses the goals of the ocean drilling under the International Phase of Ocean Drilling, which include sampling of the ocean crust at great depths and sampling of the sedimentary sequence of active and passive continental margins. (MLH)

Turbiditic systems on passive margins: fifteen years of fruitful industry-academic exchanges.

NASA Astrophysics Data System (ADS)

Guillocheau, F.

2012-04-01

During the last fifteen years, with the oil discovery in deep offshore plays, new tools have been developed that deeply modified our knowledge on sedimentary gravity processes on passive margins: geometry, physical processes, but also the importance of the topography and the quantification of the stratigraphic parameters of control. The major breakthrough was of course the extensive 3D seismic data available around most of the world margins with a focus on gravity-tectonics dominated margins. The first major progress was the characterization of the sinuous channels infilling, their diversity and different models for their origin. This also was a better knowledge of the different types of slopes (graded vs. above-graded) and the extension of the concept of accommodation to deep-water environments (ponded, healed-slope, incised submarine valley and slope accommodation). The second step was the understanding of the synsedimentary deformations for the location and the growth of turbiditic systems on margins dominated by gravity tectonics, with the importance of the sedimentary flux and its variation through time and space. The third step is now the integration of the sedimentary system, from the upstream erosional catchment to the abyssal plain (source to sink approach), with the question of the sediment routing system. During the last 100 Ma, continents experienced major changes of both topography and climate. In the case of Africa, those are (1) the growth of the plateaus (and mainly the South African one) around 90-80 Ma (Late Cretaceous) and 40-20 Ma (Late Eocene-Early Miocene) and (2) a climate evolution from hot humid (50-40 Ma) to hot dry conditions since 20-15 Ma. This evolution changed the topography, the processes of erosion and the volume and nature (weathered vs. non weathered rocks) materials. Those are primary processes for controlling the deposition of turbiditic systems, and then to predict the location of sands. This will be discussed along the Atlantic margin of Africa. Keywords: Turbidite, Passive margins, Topography, Deformation, Source to sink

SAR Interferometry as a Tool for Monitoring Coastal Changes in the Nile River Delta of Egypt

NASA Technical Reports Server (NTRS)

Aly, Mohamed H.; Klein, Andrew G.; Giardino, John R.

2005-01-01

The Nile River Delta is experiencing rapid rates of coastal change. The rate of both coastal retreat and accretion in the Eastern Nile Delta requires regular, accurate detection and measurement. Current techniques used to monitor coastal changes in the delta are point measurements and, thus, they provide a spatially limited view of the ongoing coastal changes. SAR interferometry can provide measurements of subtle coastal change at a significantly improved spatial resolution and over large areas (100 sq km). Using data provided by the ERS-1&2 satellites, monitoring can be accomplished as frequently as every 35 days when needed. Radar interferometry is employed in this study to detect segments of erosion and accretion during the 1993-2000 period. The average rates of erosion and accretion in the Eastern Nile Delta are measured to be -11.64 m/yr and +5.12 m/yr, respectively. The results of this interferometric study can be used effectively for coastal zone management and integrated sustainable development for the Nile River Delta.

Agricultural Model for the Nile Basin Decision Support System

NASA Astrophysics Data System (ADS)

van der Bolt, Frank; Seid, Abdulkarim

2014-05-01

To analyze options for increasing food supply in the Nile basin the Nile Agricultural Model (AM) was developed. The AM includes state-of-the-art descriptions of biophysical, hydrological and economic processes and realizes a coherent and consistent integration of hydrology, agronomy and economics. The AM covers both the agro-ecological domain (water, crop productivity) and the economic domain (food supply, demand, and trade) and allows to evaluate the macro-economic and hydrological impacts of scenarios for agricultural development. Starting with the hydrological information from the NileBasin-DSS the AM calculates the available water for agriculture, the crop production and irrigation requirements with the FAO-model AquaCrop. With the global commodity trade model MAGNET scenarios for land development and conversion are evaluated. The AM predicts consequences for trade, food security and development based on soil and water availability, crop allocation, food demand and food policy. The model will be used as a decision support tool to contribute to more productive and sustainable agriculture in individual Nile countries and the whole region.

Occurrence of West Nile virus antibodies in wild birds, horses, and humans in Poland.

PubMed

Niczyporuk, Jowita Samanta; Samorek-Salamonowicz, Elżbieta; Lecollinet, Sylvie; Pancewicz, Sławomir Andrzej; Kozdruń, Wojciech; Czekaj, Hanna

2015-01-01

Serum samples of 474 wild birds, 378 horses, and 42 humans with meningitis and lymphocytic meningitis were collected between 2010 and 2014 from different areas of Poland. West Nile virus (WNV) antibodies were detected using competition enzyme linked immunosorbent assays: ELISA-1 ID Screen West Nile Competition, IDvet, ELISA-2 ID Screen West Nile IgM Capture, and ELISA-3 Ingezim West Nile Compac. The antibodies were found in 63 (13.29%) out of 474 wild bird serum samples and in one (0.26%) out of 378 horse serum samples. Fourteen (33.33%) out of 42 sera from patients were positive against WNV antigen and one serum was doubtful. Positive samples obtained in birds were next retested with virus microneutralisation test to confirm positive results and cross-reactions with other antigens of the Japanese encephalitis complex. We suspect that positive serological results in humans, birds, and horses indicate that WNV can be somehow closely related with the ecosystem in Poland.

Occurrence of West Nile Virus Antibodies in Wild Birds, Horses, and Humans in Poland

PubMed Central

Niczyporuk, Jowita Samanta; Samorek-Salamonowicz, Elżbieta; Lecollinet, Sylvie; Pancewicz, Sławomir Andrzej; Kozdruń, Wojciech; Czekaj, Hanna

2015-01-01

Serum samples of 474 wild birds, 378 horses, and 42 humans with meningitis and lymphocytic meningitis were collected between 2010 and 2014 from different areas of Poland. West Nile virus (WNV) antibodies were detected using competition enzyme linked immunosorbent assays: ELISA-1 ID Screen West Nile Competition, IDvet, ELISA-2 ID Screen West Nile IgM Capture, and ELISA-3 Ingezim West Nile Compac. The antibodies were found in 63 (13.29%) out of 474 wild bird serum samples and in one (0.26%) out of 378 horse serum samples. Fourteen (33.33%) out of 42 sera from patients were positive against WNV antigen and one serum was doubtful. Positive samples obtained in birds were next retested with virus microneutralisation test to confirm positive results and cross-reactions with other antigens of the Japanese encephalitis complex. We suspect that positive serological results in humans, birds, and horses indicate that WNV can be somehow closely related with the ecosystem in Poland. PMID:25866767

Use of a tandem affinity purification assay to detect interactions between West Nile and dengue viral proteins and proteins of the mosquito vector

PubMed Central

Colpitts, Tonya M.; Cox, Jonathan; Nguyen, Annie; Feitosa, Fabiana; Krishnan, Manoj N.; Fikrig, Erol

2011-01-01

West Nile and dengue viruses are (re)emerging mosquito-borne flaviviruses that cause significant morbidity and mortality in man. The identification of mosquito proteins that associate with flaviviruses may provide novel targets to inhibit infection of the vector or block transmission to humans. Here, a tandem affinity purification (TAP) assay was used to identify 18 mosquito proteins that interact with dengue and West Nile capsid, envelope, NS2A or NS2B proteins. We further analyzed the interaction of mosquito cadherin with dengue and West Nile virus envelope protein using co-immunoprecipitation and immunofluorescence. Blocking the function of select mosquito factors, including actin, myosin, PI3-kinase and myosin light chain kinase, reduced both dengue and West Nile virus infection in mosquito cells. We show that the TAP method may be used in insect cells to accurately identify flaviviral-host protein interactions. Our data also provides several targets for interrupting flavivirus infection in mosquito vectors. PMID:21700306

Opportunities for woody crop production using treated wastewater in Egypt

Treesearch

R.S. Zalesny; S.R.  Evett; N.F. Kandil; C.  Soriano; John Stanturf

2011-01-01

The Nile River provides nearly 97% of Egypt’s freshwater supply. Egypt’s share of Nile waters is fixed at 55.5 billion cubic meters annually. As a result, Egypt will not be able to meet increasing water demand using freshwater from the Nile and has been developing non-conventional wastewater reuse strategies to meet future demands. The USAID Mission in Cairo began...

Hydrology and empire: the Nile, water imperialism and the partition of Africa.

PubMed

Tvedt, Terje

2011-01-01

Why did the British march up the Nile in the 1890s? The answers to this crucial question of imperial historiography have direct relevance for narratives and theories about imperialism, in general, and the partition of Africa in the nineteenth century, in particular. They will also influence our understanding of some of the main issues in the modern history of the whole region, including state developments and resource utilisation. This article presents an alternative to dominant interpretations of the partition of Africa and the role of British Nile policies in this context. It differs from mainstream diplomatic history, which dominates this research field, in its emphasis on how geographical factors and the hydrological characteristics of the Nile influenced and framed British thinking and actions in the region. Realising the importance of such factors and the specific character of the regional water system does not imply less attention to traditional diplomatic correspondence or to the role of individual imperial entrepreneurs. The strength of this analytical approach theoretically is that it makes it possible to locate the intentions and acts of historical subjects within specific geographical contexts. Empirically, it opens up a whole new set of source material, embedding the reconstruction of the British Nile discourse in a world of Nile plans, water works and hydrological discourses.

Yard flooding by irrigation canals increased the risk of West Nile disease in El Paso, Texas

PubMed Central

Cardenas, Victor M.; Jaime, Javier; Ford, Paula B.; Gonzalez, Fernando J.; Carrillo, Irma; Gallegos, Jorge E.; Watts, Douglas M.

2011-01-01

Purpose To investigate the effects of use of water from irrigation canals to flood residential yards on the risk of West Nile disease in El Paso, Texas. Methods West Nile disease confirmed cases in 2009–2010 were compared with a random sample of 50 residents of the county according to access to and use of water from irrigation canals by subjects or their neighbors, as well as geo-referenced closest distance between their home address and the nearest irrigation canal. A windshield survey of 600 meters around the study subjects’ home address recorded the presence of irrigation canals. The distance from the residence of 182 confirmed cases of West Nile disease reported in 2003–2010 to canals was compared to that of the centroids of 182 blocks selected at random. Results Cases were more likely than controls to report their neighbors flooded their yards with water from canals. Irrigation canals were more often observed in neighborhoods of cases than of controls. Using the set of addresses of 182 confirmed cases and 182 hypothetic controls the authors found a statistically significant inverse relation with risk of West Nile disease. Conclusions Flooding of yards with water from canals increased the risk of West Nile disease. PMID:21943648

Sensitive spectroscopic detection of large and denatured protein aggregates in solution by use of the fluorescent dye Nile red.

PubMed

Sutter, Marc; Oliveira, Sabrina; Sanders, Niek N; Lucas, Bart; van Hoek, Arie; Hink, Mark A; Visser, Antonie J W G; De Smedt, Stefaan C; Hennink, Wim E; Jiskoot, Wim

2007-03-01

The fluorescent dye Nile red was used as a probe for the sensitive detection of large, denatured aggregates of the model protein beta-galactosidase (E. coli) in solution. Aggregates were formed by irreversible heat denaturation of beta-galactosidase below and above the protein's unfolding temperature of 57.4 degrees C, and the presence of aggregates in heated solutions was confirmed by static light scattering. Interaction of Nile red with beta-galactosidase aggregates led to a shift of the emission maximum (lambda (max)) from 660 to 611 nm, and to an increase of fluorescence intensity. Time-resolved fluorescence and fluorescence correlation spectroscopy (FCS) measurements showed that Nile red detected large aggregates with hydrodynamic radii around 130 nm. By steady-state fluorescence measurements, it was possible to detect 1 nM of denatured and aggregated beta-galactosidase in solution. The comparison with size exclusion chromatography (SEC) showed that native beta-galactosidase and small aggregates thereof had no substantial effect on the fluorescence of Nile red. Large aggregates were not detected by SEC, because they were excluded from the column. The results with beta-galactosidase demonstrate the potential of Nile red for developing complementary analytical methods that overcome the size limitations of SEC, and can detect the formation of large protein aggregates at early stages.

Yard flooding by irrigation canals increased the risk of West Nile disease in El Paso, Texas.

PubMed

Cardenas, Victor M; Jaime, Javier; Ford, Paula B; Gonzalez, Fernando J; Carrillo, Irma; Gallegos, Jorge E; Watts, Douglas M

2011-12-01

To investigate the effects of use of water from irrigation canals to flood residential yards on the risk of West Nile disease in El Paso, Texas. West Nile disease confirmed cases in 2009 through 2010 were compared with a random sample of 50 residents of the county according to access to and use of water from irrigation canals by subjects or their neighbors, as well as geo-referenced closest distance between their home address and the nearest irrigation canal. A windshield survey of 600 m around the study subjects' home address recorded the presence of irrigation canals. The distance from the residence of 182 confirmed cases of West Nile disease reported in 2003 through 2010 to canals was compared with that of the centroids of 182 blocks selected at random. Cases were more likely than controls to report their neighbors flooded their yards with water from canals. Irrigation canals were more often observed in neighborhoods of cases than of controls. Using the set of addresses of 182 confirmed cases and 182 hypothetical controls the authors found a significant, inverse relation with risk of West Nile disease. Flooding of yards with water from canals increased the risk of West Nile disease. Copyright © 2011 Elsevier Inc. All rights reserved.

Long-Term Neurological Outcomes in West Nile Virus–Infected Patients: An Observational Study

PubMed Central

Weatherhead, Jill E.; Miller, Vicki E.; Garcia, Melissa N.; Hasbun, Rodrigo; Salazar, Lucrecia; Dimachkie, Mazen M.; Murray, Kristy O.

2015-01-01

The Houston West Nile Cohort (HWNC) was founded in 2002 when West Nile virus (WNV) reached Houston, TX. The long-term outcomes following WNV infection are still mostly unknown, though neurological abnormalities up to 1 year postinfection have been documented. We report an observational study of neurological abnormalities at 1–3 and 8–11 years following WNV infection in the HWNC. We conducted standard neurological examinations at two separate time points to assess changes in neurological status over time. The majority of patients (86%, 30/35) with encephalitis had abnormal neurological exam findings at the time of the first assessment compared with uncomplicated fever (27%, 3/11) and meningitis (36%, 5/14) cases. At the time of the second assessment, 57% (4/7) of West Nile fever (WNF), 33% (2/6) of West Nile meningitis (WNM), and 36% (5/14) of West Nile encephalitis (WNE) had developed new neurological complications. The most common abnormalities noted were tandem gait, hearing loss, abnormal reflexes, and muscle weakness. Long-term neurological abnormalities were most commonly found in patients who experienced primary WNV encephalitis. New abnormalities may develop over time regardless of initial clinical infection. Future studies should aim to differentiate neurological consequences due to WNV neuroinvasive infection versus neurological decline related to comorbid conditions. PMID:25802426

Deep thermal structure of Southeast Asia constrained by S-velocity data

NASA Astrophysics Data System (ADS)

Yu, Chuanhai; Shi, Xiaobin; Yang, Xiaoqiu; Zhao, Junfeng; Chen, Mei; Tang, Qunshu

2017-12-01

Southeast Asia, located in the southeastern part of the Eurasian Plate, is surrounded by tectonically active margins, exhibiting intense seismicity and volcanism, contains complex geological units with a perplexing evolution history. Because tectonic evolution is closely related to the deep thermal structure, an accurate estimation of the lithosphere thermal structure and thickness is important in extracting information on tectonics and geodynamics. However, there are significant uncertainties in the calculated deep thermal state constrained only by the observed surface heat flow. In this study, in order to obtain a better-constrained deep thermal state, we first calculate the deep thermal structure of Southeast Asia by employing an empirical relation between S-velocity and temperature, and then we estimate the base of the thermal lithosphere from the calculated temperature-depth profiles. The results show that, in general, the temperature is higher than the dry mantle solidus below the top of the seismic low-velocity zone, possibly indicating the presence of partial melt in the asthenosphere, particularly beneath oceanic basins such as the South China Sea. The temperature at a depth of 80 km in rifted and oceanic basins such as the Thailand Rift Basin, Thailand Bay, Andaman Sea, and South China Sea is about 200 °C higher than in plateaus and subduction zones such as the Khorat Plateau, Sumatra Island, and Philippine Trench regions. We suggest that the relatively cold and thick lithosphere block of the Khorat Plateau has not experienced significant internal deformation and might be extruded and rotated as a rigid block in response to the Indo-Eurasia collision. Our results show that the surface heat flow in the South China Sea is mainly dominated by the deep thermal state. There is a thermal anomaly in the Leiqiong area and in the areas adjacent to the northern margin of the South China Sea, indicating the presence of a high-temperature and thin lithosphere in the area of the well-known and controversial Hainan plume. The thermal lithosphere-asthenosphere boundary uplift area along the Xisha and southeastern Vietnam margin, in the western margin of South China Sea, which corresponds to the volcanic belt around this area, might indicate upwelling of hot mantle materials. The temperature values at 100 and 120 km depths through most regions of Southeast Asia are about 1400-1500 and 1550-1600 °C, respectively, which are nearly uniform with a small temperature difference. Our results also show that the lithosphere becomes thinner from the continent blocks toward the oceanic basins, with the smaller thickness values of 65-70 km in the South China Sea. The estimated base of the lithosphere corresponds approximately to the 1400 °C isotherm and shows good correlation with the tectonic setting.

A new model of river dynamics, hydroclimatic change and human settlement in the Nile Valley derived from meta-analysis of the Holocene fluvial archive

NASA Astrophysics Data System (ADS)

Macklin, Mark G.; Toonen, Willem H. J.; Woodward, Jamie C.; Williams, Martin A. J.; Flaux, Clément; Marriner, Nick; Nicoll, Kathleen; Verstraeten, Gert; Spencer, Neal; Welsby, Derek

2015-12-01

In the Nile catchment, a growing number of site- and reach-based studies employ radiocarbon and, more recently, OSL dating to reconstruct Holocene river histories, but there has been no attempt to critically evaluate and synthesise these data at the catchment scale. We present the first meta-analysis of published and publically available radiocarbon and OSL dated Holocene fluvial units in the Nile catchment, including the delta region, and relate this to changing climate and river dynamics. Dated fluvial units are separated both geographically (into the Nile Delta and White, Blue, and Desert Nile sub-regions) and into depositional environment (floodplain and palaeochannel fills). Cumulative probability density frequency (CPDF) plots of floodplain and palaeochannel units show a striking inverse relationship during the Holocene, reflecting abrupt (<100 years) climate-related changes in flooding regime. The CPDF plot of dated floodplain units is interpreted as a record of over-bank river flows, whilst the CPDF plot of palaeochannel units reflect periods of major flooding associated with channel abandonment and contraction, as well as transitions to multi-centennial length episodes of greater aridity and low river flow. This analysis has identified major changes in river flow and dynamics in the Nile catchment with phases of channel and floodplain contraction at c. 6150-5750, 4400-4150, 3700-3450, 2700-2250, 1350-900, 800-550 cal. BC and cal. AD 1600, timeframes that mark shifts to new hydrological and geomorphological regimes. We discuss the impacts of these changing hydromorphological regimes upon riverine civilizations in the Nile Valley.

Purification and crystallization of dengue and West Nile virus NS2B–NS3 complexes

DOE Office of Scientific and Technical Information (OSTI.GOV)

D’Arcy, Allan, E-mail: allan.darcy@novartis.com; Chaillet, Maxime; Schiering, Nikolaus

Crystals of dengue serotype 2 and West Nile virus NS2B–NS3 protease complexes have been obtained and the crystals of both diffract to useful resolution. Sample homogeneity was essential for obtaining X-ray-quality crystals of the dengue protease. Controlled proteolysis produced a crystallizable fragment of the apo West Nile virus NS2B–NS3 and crystals were also obtained in the presence of a peptidic inhibitor. Both dengue and West Nile virus infections are an increasing risk to humans, not only in tropical and subtropical areas, but also in North America and parts of Europe. These viral infections are generally transmitted by mosquitoes, but maymore » also be tick-borne. Infection usually results in mild flu-like symptoms, but can also cause encephalitis and fatalities. Approximately 2799 severe West Nile virus cases were reported this year in the United States, resulting in 102 fatalities. With this alarming increase in the number of West Nile virus infections in western countries and the fact that dengue virus already affects millions of people per year in tropical and subtropical climates, there is a real need for effective medicines. A possible therapeutic target to combat these viruses is the protease, which is essential for virus replication. In order to provide structural information to help to guide a lead identification and optimization program, crystallizations of the NS2B–NS3 protease complexes from both dengue and West Nile viruses have been initiated. Crystals that diffract to high resolution, suitable for three-dimensional structure determinations, have been obtained.« less

Usutu virus persistence and West Nile virus inactivity in the Emilia-Romagna region (Italy) in 2011.

PubMed

Calzolari, Mattia; Bonilauri, Paolo; Bellini, Romeo; Albieri, Alessandro; Defilippo, Francesco; Tamba, Marco; Tassinari, Massimo; Gelati, Antonio; Cordioli, Paolo; Angelini, Paola; Dottori, Michele

2013-01-01

The circulation of West Nile virus and Usutu virus was detected in the Emilia-Romagna region in 2008 and 2009. To evaluate the extent of circulation of both viruses, environmental surveillance, based on bird and mosquito testing, was conducted in 2008 and gradually improved over the years. In February-March 2009-2011, 5,993 hibernating mosquitoes were manually sampled, out of which 80.1% were Culex pipiens; none tested positive for the viruses. From 2008 to 2011, 946,213 mosquitoes, sampled between May and October, were tested; 86.5% were Cx. pipiens. West Nile virus was detected in 32 Cx. pipiens pools, and Usutu virus was detected in 229 mosquito pools (217 Cx. pipiens, 10 Aedes albopictus, one Anopheles maculipennis s.l., and one Aedes caspius). From 2009 to 2011, of 4,546 birds collected, 42 tested positive for West Nile virus and 48 for Usutu virus. West Nile virus and Usutu virus showed different patterns of activity during the 2008-2011 surveillance period. West Nile virus was detected in 2008, 2009, and 2010, but not in 2011. Usutu virus, however, was continuously active throughout 2009, 2010, and 2011. The data strongly suggest that both viruses overwinter in the surveyed area rather than being continually reintroduced every season. The lack of hibernating mosquitoes testing positive for the viruses and the presence of positive birds sampled early in the season support the hypothesis that the viruses overwinter in birds rather than in mosquitoes. Herd immunity in key bird species could explain the decline of West Nile virus observed in 2011, while the persistence of Usutu virus may be explained by not yet identified reservoirs. Reported results are comparable with a peri-Mediterranean circulation of the West Nile virus lineage 1 related strain, which became undetectable in the environment after two to three years of obvious circulation.

Seismic evidence of Messinian salt in opposite margins of West Mediterranean

NASA Astrophysics Data System (ADS)

Mocnik, Arianna; Camerlenghi, Angelo; Del Ben, Anna; Geletti, Riccardo; Wardell, Nigel; Zgur, Fabrizio

2015-04-01

The post drift Messinian Salinity Crisis (MSC) affected the whole Mediterranean basin, with deposition of evaporitic sequences in the deep basins, in the lower continental slopes, and in several shallower marginal basins; usually, in the continental margins, the MSC originated noticeable erosional truncations that locally cause important hiatuses in the pre-Messinian sequences, covered by the Plio-Quaternary sediments. In this work we focus on the MSC seismic signature of two new seismic datasets acquired in 2010 (West Sardinia offshore) and in 2012 (within the Eurofleet project SALTFLU in the South Balearic continental margin and the northern Algero abyssal plain). The "Messinian trilogy" recognized in the West-Mediterranean abyssal plain, is characterized by different seismic facies: the Lower evaporite Unit (LU), the salt Mobile Unit (MU) and the Upper evaporite mainly gypsiferous Unit (UU). Both seismic datasets show the presence of the Messinian trilogy also if the LU is not always clearly interpretable due to the strong seismic signal absorption by the halite layers; the salt thickness of the MU is similar in both the basins as also the thickness and stratigraphy of the UU. The Upper Unit (UU) is made up of a well reflecting package of about 10 reflectors, partially deformed by salt tectonic and characterized by a thin transparent layer that we interpreted as salt sequence inner the shallower part of the UU. Below the stratified UU, the MU exhibits a transparent layer in the deep basin and also on the foot of the slope, where a negative reflector, related to the high interval velocity of salt, marks its base. The halokinetic processes are not homogeneously distributed in the region, forming a great number of diapirs on the foot of the slope (due to the pression of the slided sediments) and giant domes toward the deep basin (due to the higher thickness of the Plio-quaternary sediments). This distribution seems to be related to the amount of salt and of the sedimentary cover. During the MSC the margins of the West Mediterranean Sea seem to be involved in some tectonic events probably connected to reactivation of normal faults and to the fast variation of the water load related to sea level fluctuations. The absence of calibrating boreholes in the deep Mediterranean basins and the hard penetration of seismic energy below the evaporitic layers, represent a limit for the knowledge of the geological evolution of the basins; the interpretation of the presented datasets could be a contribution to the comprehension of the evaporitic deposition and early-stage salt deformation during the MSC in the Mediterranean sea.

Deep Structures of The Angola Margin

NASA Astrophysics Data System (ADS)

Moulin, M.; Contrucci, I.; Olivet, J.-L.; Aslanian, D.; Géli, L.; Sibuet, J.-C.

1 Ifremer Centre de Brest, DRO/Géosciences Marines, B.P. 70, 29280 Plouzané cedex (France) mmoulin@ifremer.fr/Fax : 33 2 98 22 45 49 2 Université de Bretagne Occidentale, Institut Universitaire Europeen de la Mer, Place Nicolas Copernic, 29280 Plouzane (France) 3 Total Fina Elf, DGEP/GSR/PN -GEOLOGIE, 2,place de la Coupole-La Defense 6, 92078 Paris la Defense Cedex Deep reflection and refraction seismic data were collected in April 2000 on the West African margin, offshore Angola, within the framework of the Zaiango Joint Project, conducted by Ifremer and Total Fina Elf Production. Vertical multichannel reflection seismic data generated by a « single-bubble » air gun array array (Avedik et al., 1993) were recorded on a 4.5 km long, digital streamer, while refraction and wide angle reflection seismic data were acquired on OBSs (Ocean Bottom Seismometers). Despite the complexity of the margin (5 s TWT of sediment, salt tectonics), the combination of seismic reflection and refraction methods results in an image and a velocity model of the ground structures below the Aptian salt layer. Three large seismic units appear in the reflection seismic section from the deep part on the margin under the base of salt. The upper seismic unit is layered with reflectors parallel to the base of the salt ; it represents unstructured sediments, filling a basin. The middle unit is seismically transparent. The lower unit is characterized by highly energetic reflectors. According to the OBS refraction data, these two units correspond to the continental crust and the base of the high energetic unit corresponds to the Moho. The margin appears to be divided in 3 domains, from east to west : i) a domain with an unthinned, 30 km thick, continental crust ; ii) a domain located between the hinge line and the foot of the continental slope, where the crust thins sharply, from 30 km to less than 7 km, this domain is underlain by an anormal layer with velocities comprising between 7,2 and 7,4 km/s. The maximum thickness of this layer is located where the crust shows the strongest thinning at the foot of the continental slope ; and iii) a transitional domain, 160 km wide, with an average crustal thickness of 6 km. Moreover, no tilted blocks nor detachment faults are observed on the reflection seismic sections. The consequences of these observations on the models of crustal thinning classically used in the litterature are examined. Avedik, F., V. Renard, J-P. Allenou, B. Morvan, "Single bubble" air gun for deep exploration, Geophysics, 58, 366-382, 1993.

Environmental margin and island evolution in Middle Eastern populations of the Egyptian fruit bat.

PubMed

Hulva, P; Marešová, T; Dundarova, H; Bilgin, R; Benda, P; Bartonička, T; Horáček, I

2012-12-01

Here, we present a study of the population genetic architecture and microevolution of the Egyptian fruit bat (Rousettus aegyptiacus) at the environmental margins in the Middle East using mitochondrial sequences and nuclear microsatellites. In contrast to the rather homogenous population structure typical of cave-dwelling bats in climax tropical ecosystems, a relatively pronounced isolation by distance and population diversification was observed. The evolution of this pattern could be ascribed to the complicated demographic history at higher latitudes related to the range margin fragmentation and complex geomorphology of the studied area. Lineages from East Africa and Arabia show divergent positions. Within the northwestern unit, the most marked pattern of the microsatellite data set is connected with insularity, as demonstrated by the separate status of populations from Saharan oases and Cyprus. These demes also exhibit a reduction in genetic variability, which is presumably connected with founder effects, drift and other potential factors related to island evolution as site-specific selection. Genetic clustering indicates a semipermeability of the desert barriers in the Sahara and Arabian Peninsula and a corridor role of the Nile Valley. The results emphasize the role of the island environment in restricting the gene flow in megabats, which is also corroborated by biogeographic patterns within the family, and suggests the possibility of nascent island speciation on Cyprus. Demographic analyses suggest that the colonization of the region was connected to the spread of agricultural plants; therefore, the peripatric processes described above might be because of or strengthened by anthropogenic changes in the environment. © 2012 Blackwell Publishing Ltd.

Dengue serosurvey after a 2-month long outbreak in Nîmes, France, 2015: was there more than met the eye?

PubMed

Succo, Tiphanie; Noël, Harold; Nikolay, Birgit; Maquart, Marianne; Cochet, Amandine; Leparc-Goffart, Isabelle; Catelinois, Olivier; Salje, Henrik; Pelat, Camille; de Crouy-Chanel, Perrine; de Valk, Henriette; Cauchemez, Simon; Rousseau, Cyril

2018-06-01

BackgroundClusters of dengue cases have recently become more frequent in areas of southern France colonised by the vector mosquito Aedes albopictus . In July 2015, a 2-month outbreak of dengue virus serotype 1 (DENV-1) was reported in Nîmes. Aim: We conducted a serosurvey in the affected area at the end of the vector activity period to determine the true extent of dengue transmission. Methods: We collected capillary blood from consenting household members, and information on their medical and travel histories, and exposure to mosquito bites. Recent infections were identified using IgM and IgG anti-DENV ELISA, followed, when positive, by plaque reduction neutralisation tests on serum against DENV 1-4 and West Nile virus. The prevalence estimator was calibrated on reference demographic data. We quantified the spatial clustering of dengue cases within the affected community and inferred the transmission tree. Results: The study participation rate was 39% (564/1,431). Three of 564 participants tested positive for DENV-1 infection (after marginal calibration, 0.41%; 95% confidence interval: 0.00-0.84). The spatial analysis showed that cases were clustered at the household level. Most participants perceived the presence of mosquitos as abundant (83%) and reported frequent mosquito bites (57%). We incidentally identified six past West Nile virus infections (0.9%; 95% CI: 0.2-1.6). Conclusion: This serosurvey confirms the potential for arboviral diseases to cause outbreaks - albeit limited for now - in France and Europe.

An Integrated Hydrological and Water Management Study of the Entire Nile River System - Lake Victoria to Nile Delta

NASA Technical Reports Server (NTRS)

Habib, Shahid; Zaitchik, Benjamin; Alo, Clement; Ozdogan, Mutlu; Anderson, Martha; Policelli, Fritz

2011-01-01

The Nile basin River system spans 3 million km(exp 2) distributed over ten nations. The eight upstream riparian nations, Ethiopia, Eretria, Uganda, Rwanda, Burundi, Congo, Tanzania and Kenya are the source of approximately 86% of the water inputs to the Nile, while the two downstream riparian countries Sudan and Egypt, presently rely on the river's flow for most of the their needs. Both climate and agriculture contribute to the complicated nature of Nile River management: precipitation in the headwaters regions of Ethiopia and Lake Victoria is variable on a seasonal and inter-annual basis, while demand for irrigation water in the arid downstream region is consistently high. The Nile is, perhaps, one of the most difficult trans-boundary water issue in the world, and this study would be the first initiative to combine NASA satellite observations with the hydrologic models study the overall water balance in a to comprehensive manner. The cornerstone application of NASA's Earth Science Research Results under this project are the NASA Land Data Assimilation System (LDAS) and the USDA Atmosphere-land Exchange Inverse (ALEXI) model. These two complementary research results are methodologically independent methods for using NASA observations to support water resource analysis in data poor regions. Where an LDAS uses multiple sources of satellite data to inform prognostic simulations of hydrological process, ALEXI diagnoses evapotranspiration and water stress on the basis of thermal infrared satellite imagery. Specifically, this work integrates NASA Land Data Assimilation systems into the water management decision support systems that member countries of the Nile Basin Initiative (NBI) and Regional Center for Mapping of Resources for Development (RCMRD, located in Nairobi, Kenya) use in water resource analysis, agricultural planning, and acute drought response to support sustainable development of Nile Basin water resources. The project is motivated by the recognition that accurate, frequent, and spatially distributed estimates of the water balance are necessary for effective water management. This creates a challenge for watersheds that are large, include data poor regions, and/or span multiple nations. All of these descriptors apply to the Nile River basin, yet successful management of the Nile is critical for development and political stability in the region. For this reason, improved hydrological data to support cooperative water management in the Nile basin is a priority for USAID, the US State Department, the World Bank and other international organizations. In this project, the U.S. based research team is working with partners at RCMRD, Nile Basin Initiative (NBI), and their member national-level agencies to develop satellite-based land cover maps, satellite-derived evapotranspiration estimates (using the ALEXI algorithm), and NASA's Land Data Assimilation System (LDAS) customized to match identified information needs. The cornerstone applied sciences product of the project is the development of a customized "Nile LDAS" that will produce optimal estimates of hydrological states and fluxes, as vetted against the in situ observations of NBI and RCMRD member organizations and independent satellite-derived hydrological estimates. Nile LDAS will be applied to improve the reliability of emerging Decision Support Systems in applications that include drought monitoring, reservoir management, and irrigation planning. The end-users such as RCMRD, NBI, Ethiopian and Kenya Meteorological and Famine Early Warning System Network (FEWSNet) will be the eventual benefactors of this work. There will be a capacity building process involving the above end-user organizations and transfer the models and the results for these organizations to execute for future use. The team has already initiated this study and the early results of first years' work are shown. The plan is to complete this work by late 2013.

Deep Drilling Results in the Atlantic Ocean: Continental Margins and Paleoenvironment

DTIC Science & Technology

1979-01-01

nannoplankton, a sparse to rich DITIBTO OF HORIZO C I foraminiferal fauna (simple arenaceous foramin - 5S SSftB / ifera, lagenids, epistominids, and primitive...Deep Sea Pessagno, E.A., Jr., Mesozoic Planctonic Foramin - DrillingP , 11, Washington (U.S. Govern- vera and Radiolaria, in Ewing, M., Worzel, L.J. ment...Strati- B.,er, W.H., Foramin ooze: solution at graphic Micropaleontology of Atlantic Basins depths, Science, 156, 383-385, 1967. and Borderlands

Conflicts of Shared Resources: A Case Study of River Nile

DTIC Science & Technology

2012-03-22

as Lake Kivu. Rwanda joined the earlier Nile basin project, Hydromet , in 1967, with the support on the UNDP. 18 Although the country does not...operation Hydromet . In 1967, with the assistance of the United Nations Development Program (UNDP) and the World Meteorological Organization (WMO), Egypt...Kenya, Sudan, Tanzania and Uganda launched the Hydromet Survey project to regulate the water level of the Nile.”30 Rwanda joined later while Ethiopia

Peri-operative imaging of cancer margins with reflectance confocal microscopy during Mohs micrographic surgery: feasibility of a video-mosaicing algorithm

NASA Astrophysics Data System (ADS)

Flores, Eileen; Yelamos, Oriol; Cordova, Miguel; Kose, Kivanc; Phillips, William; Rossi, Anthony; Nehal, Kishwer; Rajadhyaksha, Milind

2017-02-01

Reflectance confocal microscopy (RCM) imaging shows promise for guiding surgical treatment of skin cancers. Recent technological advancements such as the introduction of the handheld version of the reflectance confocal microscope, video acquisition and video-mosaicing have improved RCM as an emerging tool to evaluate cancer margins during routine surgical skin procedures such as Mohs micrographic surgery (MMS). Detection of residual non-melanoma skin cancer (NMSC) tumor during MMS is feasible, as demonstrated by the introduction of real-time perioperative imaging on patients in the surgical setting. Our study is currently testing the feasibility of a new mosaicing algorithm for perioperative RCM imaging of NMSC cancer margins on patients during MMS. We report progress toward imaging and image analysis on forty-five patients, who presented for MMS at the MSKCC Dermatology service. The first 10 patients were used as a training set to establish an RCM imaging algorithm, which was implemented on the remaining test set of 35 patients. RCM imaging, using 35% AlCl3 for nuclear contrast, was performed pre- and intra-operatively with the Vivascope 3000 (Caliber ID). Imaging was performed in quadrants in the wound, to simulate the Mohs surgeon's examination of pathology. Videos were taken at the epidermal and deep dermal margins. Our Mohs surgeons assessed all videos and video-mosaics for quality and correlation to histology. Overall, our RCM video-mosaicing algorithm is feasible. RCM videos and video-mosaics of the epidermal and dermal margins were found to be of clinically acceptable quality. Assessment of cancer margins was affected by type of NMSC, size and location. Among the test set of 35 patients, 83% showed acceptable imaging quality, resolution and contrast. Visualization of nuclear and cellular morphology of residual BCC/SCC tumor and normal skin features could be detected in the peripheral and deep dermal margins. We observed correlation between the RCM videos/video-mosaics and the corresponding histology in 32 lesions. Peri-operative RCM imaging shows promise for improved and faster detection of cancer margins and guiding MMS in the surgical setting.

Identification of channel geometries applying seismic attributes and spectral decomposition techniques, Temsah Field, Offshore East Nile Delta, Egypt

NASA Astrophysics Data System (ADS)

Othman, Adel A. A.; Fathy, M.; Negm, Adel

2018-06-01

The Temsah field is located in eastern part of the Nile delta to seaward. The main reservoirs of the area are Middle Pliocene mainly consist from siliciclastic which associated with a close deep marine environment. The Distribution pattern of the reservoir facies is limited scale indicating fast lateral and vertical changes which are not easy to resolve by applying of conventional seismic attribute. The target of the present study is to create geophysical workflows to a better image of the channel sand distribution in the study area. We apply both Average Absolute Amplitude and Energy attribute which are indicated on the distribution of the sand bodies in the study area but filled to fully described the channel geometry. So another tool, which offers more detailed geometry description is needed. The spectral decomposition analysis method is an alternative technique focused on processing Discrete Fourier Transform which can provide better results. Spectral decomposition have been done over the upper channel shows that the frequency in the eastern part of the channel is the same frequency in places where the wells are drilled, which confirm the connection of both the eastern and western parts of the upper channel. Results suggest that application of the spectral decomposition method leads to reliable inferences. Hence, using the spectral decomposition method alone or along with other attributes has a positive impact on reserves growth and increased production where the reserve in the study area increases to 75bcf.

The Sulu Sea as Carbon Dioxide Sink

NASA Astrophysics Data System (ADS)

Ferrera, C. M.; Jacinto, G. S.; Chen, C. T. A.

2016-12-01

The Sulu Sea, one of the marginal seas in the West Pacific and the largest internal sea in the Philippines, is characterized by its unique deep water ventilation pattern and high sediment organic carbon and CaCO3 content. Studies on the dissolved CO2 system in the Sulu Sea have remarkably shown that anthropogenic CO2 has already penetrated to the bottom of this 5km-deep basin, albeit limited to a dataset from a single station in December 1996. To further understand the role of this tropical marginal sea as CO2 sink and to assess its behavior as a CO2 sink during the 11-year period, water samples for dissolved CO2 parameters from two deep stations of high productivity and low productivity were collected in December 2007/January 2008 and were compared with the 1996 data. Results suggest that the surface waters in the low productivity region might have been acidifying at a rate of -0.0012 pH unit yr-1. Atmospheric CO2 increased at +1.9 ppmv yr-1 and seawater fCO2 at +3.30 μatm yr-1. Through deep water ventilation, anthropogenic CO2 has penetrated the water column thereby making the deeper waters a sink of anthropogenic CO2. But then the presence and dissolution of CaCO3 deposits at the sea floor and along the Sulu Sea slopes as a result of the reaction with this anthropogenic CO2 probably neutralizes the acidification at depths as shown by the increase in total alkalinity (+0.57 μmol kg-1 yr-1), and facilitates further uptake of CO2 from the atmosphere. Therefore, productivity at Sulu Sea surface waters results to sequestration of CO2 from the atmosphere to the sediment sink through organic carbon and CaCO3 deposits. While high temperature and low productivity surface waters make the Sulu Sea a source of CO2 to the atmosphere, ventilation patterns make the deep waters of the Sulu Sea an efficient sink for anthropogenic CO2. Given the larger area occupied by the CO2 sink deep waters compared to the CO2 source surface waters including an upwelling area, the Sulu Sea could possibly be a "net" CO2 sink, an important contribution to the otherwise underestimated inventory of CO2 from marginal seas.

Decadal biogeochemical history of the south east Levantine basin: Simulations of the river Nile regimes

NASA Astrophysics Data System (ADS)

Suari, Yair; Brenner, Steve

2015-08-01

The south eastern Mediterranean is characterized by antiestuarine circulation which leads to extreme oligotrophic conditions. The Nile river that used to transport fresh water and nutrients into the basin was dammed in 1964 which led to a drastic reduction of fresh water fluxes, and later, changes in Egyptian agriculture and diet led to increased nutrient fluxes. In this paper we present the results of simulations with a biogeochemical model of the south eastern Mediterranean. Four experiments were conducted: (1) present day without riverine inputs; (2) Nile before damming (pre-1964); (3) post-damming 1995 Nile; and (4) fresh water and nutrient discharges of Israeli coastal streams. The present day input simulation (control run) successfully reproduced measured nutrient concentrations, with the exception of simulated chlorophyll concentrations which were slightly higher than observed. The pre-1964 Nile simulation showed a salinity reduction of 2 psu near the Egyptian coast and 0.5 psu along the Israeli coast, as well as elevated chlorophyll a concentrations mostly east of the Nile delta and north to Cyprus. The spring bloom extended from its present peak during February-March to a peak during February-May. The 1995 Nile simulation showed increased chlorophyll a concentrations close to the Egyptian coast. The Israeli coastal stream simulation showed that the effect of the Israeli coastal stream winter flow on chlorophyll converged to control concentrations within about one month, demonstrating the stability and sensitivity of the model to external forcing. The results of this study demonstrate the significance of fresh water fluxes in maintaining marine productivity, which may have large scale effects on the marine ecosystem.

Does intra-individual neurocognitive variability relate to neuroinvasive disease and quality of life in West Nile Virus?

PubMed

Sheppard, David P; Woods, Steven Paul; Hasbun, Rodrigo; Salazar, Lucrecia; Nolan, Melissa S; Murray, Kristy O

2018-04-25

West Nile Virus (WNV) can be a neuroinvasive pathogen that may produce persistent mild-to-moderate neurocognitive impairments in some infected persons. Intra-individual variability (IIV) is an index of a person's performance across a neuropsychological test or battery, which is an indicator of neurocognitive control and integrity of prefrontal systems. The present study examined possible associations of IIV to neurological health and well-being in WNV infection. Participants included 84 adults with a range of clinical WNV disease (31 West Nile Encephalitis, 16 West Nile Meningitis, 37 West Nile Fever) who completed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). IIV was operationalized as covariance of variation (CoV), or the intra-individual standard deviation across 5 age-adjusted RBANS standard scores divided by the mean of standard scores. Participants were assessed for health-related quality of life (QoL) using the RAND 36-item short form health survey (SF-36). Analyses revealed that the West Nile Encephalitis group had higher neurocognitive CoV compared to the West Nile Fever group, and this difference was associated with a medium effect size (Cohen's d = .52). Mixed linear models controlling for estimated IQ, activities of daily living, depression, neuroinvasive disease groups, and fatigue showed that higher RBANS CoV was associated with lower physical, but not mental health QoL. In persons with WNV infection, there is a modest association between elevations in IIV and encephalitis, and even subtle disruptions in neuropsychological functioning show relationships with important self-reported functioning as measured by physical health quality of life. Future studies should examine whether IIV predicts long-term health outcomes (e.g., mortality) in individuals infected with WNV.

Liquefaction potential of Nile delta, Egypt

NASA Astrophysics Data System (ADS)

Fergany, Elsayed; Omar, Khaled

2017-06-01

Understanding how sedimentary basins respond to seismic-wave energy generated by earthquake events is a significant concern for seismic-hazard estimation and risk analysis. The main goal of this study is assessing the vulnerability index, Kg, as an indicator for liquefaction potential sites in the Nile delta basin based on the microtremor measurements. Horizontal to Vertical spectral ratio analyses (HVSR) of ambient noise data, which was conducted in 2006 at 120 sites covering the Nile delta from south to north were reprocessed using Geopsy software. HVSR factors of amplification, A, and fundamental frequency, F, were calculated and Kg was estimated for each measurement. The Kg value varies widely from south toward north delta and the potential liquefaction places were estimated. The higher vulnerability indices are associated with sites located in southern part of the Nile delta and close to the branches of Nile River. The HVSR factors were correlated with geologic setting of the Nile delta and show good correlations with the sediment thickness and subsurface stratigraphic boundaries. However, we note that sites located in areas that have greatest percentage of sand also yielded relatively high Kg values with respect to sites in areas where clay is abundant. We concluded that any earthquake with ground acceleration more than 50 gal at hard rock can cause a perceived deformation of sandy sediments and liquefaction can take place in the weak zones of Kg ≥ 20. The worst potential liquefaction zones (Kg > 30) are frequently joined to the Damietta and Rosetta Nile River branches and south Delta where relatively coarser sand exists. The HVSR technique is a very sensitive tool for lithological stratigraphy variations in two dimensions and varying liquefaction susceptibility.

Cairo, Egypt/Nile River viewed from STS-66 Atlantis

NASA Image and Video Library

1994-11-14

This close-up view of the intensively cultivated Nile River flood plain near Cairo presents a sharp color contrast to the virtually non-vegetated, sandy desert, located to the west of the vegetated area. Some rectangular cultivated field patterns, as well as circular center pivot irrigation patterns, can be observed northwest of the Nile River flood plain. The world famous Giza Pyramids are located near the center of this photography (see highly reflective sand surfaces).

West Nile virus infection and postoperative neurological symptoms: a case report and review of the literature.

PubMed

Moreland, Natalie C; Hemmer, Laura B; Koht, Antoun

2014-08-01

The incidence of West Nile virus, which may cause a range of clinical presentations including subclinical infections, mild febrile illness, meningitis, or encephalitis, has increased over recent years. Rare complications, including optic neuritis, also have been reported. A patient who presented with preoperative asymptomatic West Nile virus developed fever, altered mental status and temporary vision loss after elective multilevel spine fusion surgery. Copyright © 2014 Elsevier Inc. All rights reserved.

DNA Vaccine for West Nile Virus Infection in Fish Crows (Corvus ossifragus)

DTIC Science & Technology

2003-09-01

SUBJECT TERMS west Nile virus, vaccine , efficacy , crows 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18. NUMBER OF PAGES 5 19a...A DNA vaccine for West Nile virus (WNV) was evaluat- ed to determine whether its use could protect fish crows (Corvus ossifragus) from fatal WNV...infection. Captured adult crows were given 0.5 mg of the DNA vaccine either orally or by intramuscular (IM) inoculation; control crows were inoculated or

The organic geochemical characterization: An indication of type of kerogen and maturity of early - Mid Jurassic shale in the Blue Nile formation

NASA Astrophysics Data System (ADS)

Shoieba, Monera Adam; Sum, Chow Weng; Abidin, Nor Syazwani Zainal; Bhattachary, Swapan Kumar

2018-06-01

The heterogeneity and complexity of shale gas has become clear as the development of unconventional resources have improved. The Blue Nile Basin, is one of the many Mesozoic rift basins in Sudan associated with the Central African Rift System (CARS). It is located in the eastern part of the Republic of Sudan and has been the major focus for shale gas exploration due to the hydrocarbon found in the basin. But so far no success of discovery has been achieved because the shale gas potentiality of the study area is still unknown. The objective of this study is to assess the type of kerogen and maturity of the shale samples from the Blue Nile Formation within the Blue Nile Basin. This was done by employing organic geochemical methods such as pyrolysis gas chromatography (Py-GC) and petrographic analysis such as vitrinite reflectance (Ro%). Ten representative shale samples from TW-1 well in the Blue Nile Formation have been used to assess the quality of the source rock. Pyrolysis GC analysis indicate that all the selected shale samples contain Type II kerogen that produces oil and gas. The Blue Nile Formation possesses vitrinite reflectance (Ro%) of 0.60-0.65%, indicating that the shale samples are mature in the oil window.

The effects of composting on the nutritional composition of fibrous bio-regenerative life support systems (BLSS) plant waste residues and its impact on the growth of Nile tilapia ( Oreochromis niloticus)

NASA Astrophysics Data System (ADS)

Gonzales, John M.; Lowry, Brett A.; Brown, Paul B.; Beyl, Caula A.; Nyochemberg, Leopold

2009-04-01

Utilization of bio-regenerative life support systems (BLSS) plant waste residues as a nutritional source by Nile tilapia ( Oreochromis niloticus) has proven problematic as a result of high concentrations of fibrous compounds in the plant waste residues. Nutritional improvement of plant waste residues by composting with the oyster mushroom ( Pleurotus ostreatus), and the effects on growth and nutrient utilization of Nile tilapia fed such residues were evaluated. Five Nile tilapia (mean weight = 70.9 ± 3.1 g) were stocked in triplicate aquaria and fed one of two experimental diets, cowpea (CP) and composted cowpea (CCP), twice daily for a period of 8 weeks. Composting of cowpea residue resulted in reduced concentrations of nitrogen-free extract, hemi-cellulose and trypsin inhibitor activity, though trypsin inhibitor activity remained high. Composting did not reduce crude fiber, lignin, or cellulose concentrations in the diet. No significant differences ( P < 0.05) were observed in weight gain, specific growth rate, survival rate, daily consumption, and food conversion ratio between tilapia fed CP and CCP. These results suggest that P. ostreatus is not a suitable candidate for culture in conjunction with the culture of Nile tilapia. Additional work is needed to determine what, if any, benefit can be obtained from incorporating composted residue as feed for Nile tilapia.

[West Nile virus transmission risk in the Czech Republic].

PubMed

Vlčková, J; Rupeš, V; Horáková, D; Kollárová, H; Holý, O

2015-06-01

West Nile Virus (WNV) belongs to the family Flaviviridae. It is transmitted to humans by mosquitoes, capable of sucking blood on birds and mammals, most often by mosquitoes of the genus Culex. In humans, the virus was first identified in 1937 in the West Nile region, Uganda, Africa. Later, the virus spread and caused more or less severe epidemics of West Nile fever in North Africa, Europe, Asia, and North and South America. During the last two decades, WNV has been on the rise and is currently ranked as one of the most prevalent arboviruses in the world. In humans, WNV infection mostly occurs as asymptomatic, but may have a more severe or even fatal course in older and weakened patients. Humans may become infected not only by mosquitoes that acquire the virus from infected birds, but also through a blood transfusion, organ transplant, breast milk and transplacental transmission, or contact with infected animals, their blood, and tissues. The first autochthonous human case of West Nile fever in the Czech Republic was reported from South Moravia in 1997. In 2013, another case of West Nile fever emerged in this country, in the Ostrava area. The issue of WNV has recently been studied from many different perspectives, as evidenced by many original and review papers. This article briefly reviews the essential knowledge about this virus and its spread.

Long-term neurological outcomes in West Nile virus-infected patients: an observational study.

PubMed

Weatherhead, Jill E; Miller, Vicki E; Garcia, Melissa N; Hasbun, Rodrigo; Salazar, Lucrecia; Dimachkie, Mazen M; Murray, Kristy O

2015-05-01

The Houston West Nile Cohort (HWNC) was founded in 2002 when West Nile virus (WNV) reached Houston, TX. The long-term outcomes following WNV infection are still mostly unknown, though neurological abnormalities up to 1 year postinfection have been documented. We report an observational study of neurological abnormalities at 1-3 and 8-11 years following WNV infection in the HWNC. We conducted standard neurological examinations at two separate time points to assess changes in neurological status over time. The majority of patients (86%, 30/35) with encephalitis had abnormal neurological exam findings at the time of the first assessment compared with uncomplicated fever (27%, 3/11) and meningitis (36%, 5/14) cases. At the time of the second assessment, 57% (4/7) of West Nile fever (WNF), 33% (2/6) of West Nile meningitis (WNM), and 36% (5/14) of West Nile encephalitis (WNE) had developed new neurological complications. The most common abnormalities noted were tandem gait, hearing loss, abnormal reflexes, and muscle weakness. Long-term neurological abnormalities were most commonly found in patients who experienced primary WNV encephalitis. New abnormalities may develop over time regardless of initial clinical infection. Future studies should aim to differentiate neurological consequences due to WNV neuroinvasive infection versus neurological decline related to comorbid conditions. © The American Society of Tropical Medicine and Hygiene.

Fungal and Prokaryotic Activities in the Marine Subsurface Biosphere at Peru Margin and Canterbury Basin Inferred from RNA-Based Analyses and Microscopy

PubMed Central

Pachiadaki, Maria G.; Rédou, Vanessa; Beaudoin, David J.; Burgaud, Gaëtan; Edgcomb, Virginia P.

2016-01-01

The deep sedimentary biosphere, extending 100s of meters below the seafloor harbors unexpected diversity of Bacteria, Archaea, and microbial eukaryotes. Far less is known about microbial eukaryotes in subsurface habitats, albeit several studies have indicated that fungi dominate microbial eukaryotic communities and fungal molecular signatures (of both yeasts and filamentous forms) have been detected in samples as deep as 1740 mbsf. Here, we compare and contrast fungal ribosomal RNA gene signatures and whole community metatranscriptomes present in sediment core samples from 6 and 95 mbsf from Peru Margin site 1229A and from samples from 12 and 345 mbsf from Canterbury Basin site U1352. The metatranscriptome analyses reveal higher relative expression of amino acid and peptide transporters in the less nutrient rich Canterbury Basin sediments compared to the nutrient rich Peru Margin, and higher expression of motility genes in the Peru Margin samples. Higher expression of genes associated with metals transporters and antibiotic resistance and production was detected in Canterbury Basin sediments. A poly-A focused metatranscriptome produced for the Canterbury Basin sample from 345 mbsf provides further evidence for active fungal communities in the subsurface in the form of fungal-associated transcripts for metabolic and cellular processes, cell and membrane functions, and catalytic activities. Fungal communities at comparable depths at the two geographically separated locations appear dominated by distinct taxa. Differences in taxonomic composition and expression of genes associated with particular metabolic activities may be a function of sediment organic content as well as oceanic province. Microscopic analysis of Canterbury Basin sediment samples from 4 and 403 mbsf produced visualizations of septate fungal filaments, branching fungi, conidiogenesis, and spores. These images provide another important line of evidence supporting the occurrence and activity of fungi in the deep subseafloor biosphere. PMID:27375571

Fungal and Prokaryotic Activities in the Marine Subsurface Biosphere at Peru Margin and Canterbury Basin Inferred from RNA-Based Analyses and Microscopy.

PubMed

Pachiadaki, Maria G; Rédou, Vanessa; Beaudoin, David J; Burgaud, Gaëtan; Edgcomb, Virginia P

2016-01-01

The deep sedimentary biosphere, extending 100s of meters below the seafloor harbors unexpected diversity of Bacteria, Archaea, and microbial eukaryotes. Far less is known about microbial eukaryotes in subsurface habitats, albeit several studies have indicated that fungi dominate microbial eukaryotic communities and fungal molecular signatures (of both yeasts and filamentous forms) have been detected in samples as deep as 1740 mbsf. Here, we compare and contrast fungal ribosomal RNA gene signatures and whole community metatranscriptomes present in sediment core samples from 6 and 95 mbsf from Peru Margin site 1229A and from samples from 12 and 345 mbsf from Canterbury Basin site U1352. The metatranscriptome analyses reveal higher relative expression of amino acid and peptide transporters in the less nutrient rich Canterbury Basin sediments compared to the nutrient rich Peru Margin, and higher expression of motility genes in the Peru Margin samples. Higher expression of genes associated with metals transporters and antibiotic resistance and production was detected in Canterbury Basin sediments. A poly-A focused metatranscriptome produced for the Canterbury Basin sample from 345 mbsf provides further evidence for active fungal communities in the subsurface in the form of fungal-associated transcripts for metabolic and cellular processes, cell and membrane functions, and catalytic activities. Fungal communities at comparable depths at the two geographically separated locations appear dominated by distinct taxa. Differences in taxonomic composition and expression of genes associated with particular metabolic activities may be a function of sediment organic content as well as oceanic province. Microscopic analysis of Canterbury Basin sediment samples from 4 and 403 mbsf produced visualizations of septate fungal filaments, branching fungi, conidiogenesis, and spores. These images provide another important line of evidence supporting the occurrence and activity of fungi in the deep subseafloor biosphere.

Purpura fulminans associated with acute West Nile virus encephalitis.

PubMed

Shah, Sheevam; Fite, Laura Paul; Lane, Natalie; Parekh, Palak

2016-02-01

Purpura fulminans is a progressive thrombotic disorder that presents with widespread purpura due to deficiency or dysfunction of protein C or protein S. Lesions present as well-demarcated erythematous macules that progress to irregular areas of hemorrhagic necrosis.West Nile virus is a member of the Flaviviridae family transmitted to humans through the bite of various mosquito species. It manifests as West Nile fever in 25% of those infected and less commonly as neuroinvasive disease. An African American man in his fortiespresented with altered mental status and was noted to have evidence of disseminated intravascular coagulation according to his lab data. He then developed dusky skin discoloration and systemic flaccid bullae with desquamation. Biopsy was consistent with purpura fulminans and the patient eventually developed symmetric peripheral gangrene, requiring amputations of all four extremities. Infectious work up revealed positive testing for IgM and IgG antibodies in serum and cerebrospinal fluid leading to the diagnosis of acute West Nile Virus encephalitis. We present this case to describe the rarely reported association of purpura fulminans with West Nile Virus infection. Copyright © 2015 Elsevier B.V. All rights reserved.

The Nile

NASA Technical Reports Server (NTRS)

2001-01-01

This image of the northern portion of the Nile River was captured by MISR's nadir camera on January 30, 2001 (Terra orbit 5956). The Nile is the longest river in the world, extending for about 6700 kilometers from its headwaters in the highlands of eastern Africa.

At the apex of the fertile Nile River Delta is the Egyptian capital city of Cairo. To the west are the Great Pyramids of Giza. North of here the Nile branches into two distributaries, the Rosetta to the west and the Damietta to the east.

Also visible in this image is the Suez Canal, a shipping waterway connecting Port Said on the Mediterranean Sea with the Gulf of Suez. The Gulf is an arm of the Red Sea, and is located on the righthand side of the picture.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Overview of Petroleum Settings in Deep Waters of the Brazilian South Atlantic Margin

NASA Astrophysics Data System (ADS)

Anjos, Sylvia; Penteado, Henrique; Oliveira, Carlos M. M.

2015-04-01

The objective of this work is to present an overall view of the tectonic and stratigraphic evolution of the western South Atlantic with focus on the Brazilian marginal basins. It includes the structural evolution, stratigraphic sequences, depositional environments and petroleum systems model along the Brazilian marginal basins. In addition, a description of the main petroleum provinces and selected plays including the pre-salt carbonates and post-salt turbidite reservoirs is presented. Source-rock ages and types, trap styles, main reservoir characteristics, petroleum compositions, and recent exploration results are discussed. Finally, an outlook and general assessment of the impact of the large pre-salt discoveries on the present-day and future production curves are given.

Noncoding Subgenomic Flavivirus RNA Is Processed by the Mosquito RNA Interference Machinery and Determines West Nile Virus Transmission by Culex pipiens Mosquitoes.

PubMed

Göertz, G P; Fros, J J; Miesen, P; Vogels, C B F; van der Bent, M L; Geertsema, C; Koenraadt, C J M; van Rij, R P; van Oers, M M; Pijlman, G P

2016-11-15

Flaviviruses, such as Zika virus, yellow fever virus, dengue virus, and West Nile virus (WNV), are a serious concern for human health. Flaviviruses produce an abundant noncoding subgenomic flavivirus RNA (sfRNA) in infected cells. sfRNA results from stalling of the host 5'-3' exoribonuclease XRN1/Pacman on conserved RNA structures in the 3' untranslated region (UTR) of the viral genomic RNA. sfRNA production is conserved in insect-specific, mosquito-borne, and tick-borne flaviviruses and flaviviruses with no known vector, suggesting a pivotal role for sfRNA in the flavivirus life cycle. Here, we investigated the function of sfRNA during WNV infection of Culex pipiens mosquitoes and evaluated its role in determining vector competence. An sfRNA1-deficient WNV was generated that displayed growth kinetics similar to those of wild-type WNV in both RNA interference (RNAi)-competent and -compromised mosquito cell lines. Small-RNA deep sequencing of WNV-infected mosquitoes indicated an active small interfering RNA (siRNA)-based antiviral response for both the wild-type and sfRNA1-deficient viruses. Additionally, we provide the first evidence that sfRNA is an RNAi substrate in vivo Two reproducible small-RNA hot spots within the 3' UTR/sfRNA of the wild-type virus mapped to RNA stem-loops SL-III and 3' SL, which stick out of the three-dimensional (3D) sfRNA structure model. Importantly, we demonstrate that sfRNA-deficient WNV displays significantly decreased infection and transmission rates in vivo when administered via the blood meal. Finally, we show that transmission and infection rates are not affected by sfRNA after intrathoracic injection, thereby identifying sfRNA as a key driver to overcome the mosquito midgut infection barrier. This is the first report to describe a key biological function of sfRNA for flavivirus infection of the arthropod vector, providing an explanation for the strict conservation of sfRNA production. Understanding the flavivirus transmission cycle is important to identify novel targets to interfere with disease and to aid development of virus control strategies. Flaviviruses produce an abundant noncoding viral RNA called sfRNA in both arthropod and mammalian cells. To evaluate the role of sfRNA in flavivirus transmission, we infected mosquitoes with the flavivirus West Nile virus and an sfRNA-deficient mutant West Nile virus. We demonstrate that sfRNA determines the infection and transmission rates of West Nile virus in Culex pipiens mosquitoes. Comparison of infection via the blood meal versus intrathoracic injection, which bypasses the midgut, revealed that sfRNA is important to overcome the mosquito midgut barrier. We also show that sfRNA is processed by the antiviral RNA interference machinery in mosquitoes. This is the first report to describe a pivotal biological function of sfRNA in arthropods. The results explain why sfRNA production is evolutionarily conserved. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Noncoding Subgenomic Flavivirus RNA Is Processed by the Mosquito RNA Interference Machinery and Determines West Nile Virus Transmission by Culex pipiens Mosquitoes

PubMed Central

Göertz, G. P.; Fros, J. J.; Miesen, P.; Vogels, C. B. F.; van der Bent, M. L.; Geertsema, C.; Koenraadt, C. J. M.; van Oers, M. M.

2016-01-01

ABSTRACT Flaviviruses, such as Zika virus, yellow fever virus, dengue virus, and West Nile virus (WNV), are a serious concern for human health. Flaviviruses produce an abundant noncoding subgenomic flavivirus RNA (sfRNA) in infected cells. sfRNA results from stalling of the host 5′-3′ exoribonuclease XRN1/Pacman on conserved RNA structures in the 3′ untranslated region (UTR) of the viral genomic RNA. sfRNA production is conserved in insect-specific, mosquito-borne, and tick-borne flaviviruses and flaviviruses with no known vector, suggesting a pivotal role for sfRNA in the flavivirus life cycle. Here, we investigated the function of sfRNA during WNV infection of Culex pipiens mosquitoes and evaluated its role in determining vector competence. An sfRNA1-deficient WNV was generated that displayed growth kinetics similar to those of wild-type WNV in both RNA interference (RNAi)-competent and -compromised mosquito cell lines. Small-RNA deep sequencing of WNV-infected mosquitoes indicated an active small interfering RNA (siRNA)-based antiviral response for both the wild-type and sfRNA1-deficient viruses. Additionally, we provide the first evidence that sfRNA is an RNAi substrate in vivo. Two reproducible small-RNA hot spots within the 3′ UTR/sfRNA of the wild-type virus mapped to RNA stem-loops SL-III and 3′ SL, which stick out of the three-dimensional (3D) sfRNA structure model. Importantly, we demonstrate that sfRNA-deficient WNV displays significantly decreased infection and transmission rates in vivo when administered via the blood meal. Finally, we show that transmission and infection rates are not affected by sfRNA after intrathoracic injection, thereby identifying sfRNA as a key driver to overcome the mosquito midgut infection barrier. This is the first report to describe a key biological function of sfRNA for flavivirus infection of the arthropod vector, providing an explanation for the strict conservation of sfRNA production. IMPORTANCE Understanding the flavivirus transmission cycle is important to identify novel targets to interfere with disease and to aid development of virus control strategies. Flaviviruses produce an abundant noncoding viral RNA called sfRNA in both arthropod and mammalian cells. To evaluate the role of sfRNA in flavivirus transmission, we infected mosquitoes with the flavivirus West Nile virus and an sfRNA-deficient mutant West Nile virus. We demonstrate that sfRNA determines the infection and transmission rates of West Nile virus in Culex pipiens mosquitoes. Comparison of infection via the blood meal versus intrathoracic injection, which bypasses the midgut, revealed that sfRNA is important to overcome the mosquito midgut barrier. We also show that sfRNA is processed by the antiviral RNA interference machinery in mosquitoes. This is the first report to describe a pivotal biological function of sfRNA in arthropods. The results explain why sfRNA production is evolutionarily conserved. PMID:27581979

Drilling through the Messinian evaporites: the beginning of a new adventure?

NASA Astrophysics Data System (ADS)

Bassetti, M. A.; Lofi, J.

2009-04-01

The sensitivity of past environments tell us a lot about the nature of changes, either of climatic or geodynamic origin. In this respect, the Mediterranean basin represents the ideal natural laboratory for studying the interaction between deep processes, tectonics, sedimentary fluxes and sea-level oscillation that are at the origin of the sedimentary records. A spectacular example of reactivity of this system have been experienced less than 6 Myrs ago, when the pan-Mediterranean realm underwent rapid and abrupt changes of paleo-environmental parameters that led to the well known Messinian Salinity Crisis (MSC, Hsü et al., 1973). This short-term event at the geological scale (~5.96-5.32 Ma) results from the progressive closure of the two-way connection between the Atlantic Ocean and the Mediterranean Sea. The most important characteristics of this event are: (1) a reduction of the Atlantic water supply having as a consequence, an increased salinity and in the precipitation of thick evaporites within shallow water marginal basins (presently disconnected from the deep basins); (2) a subsequent major sea-level fall exceeding 2000 m and resulting in the massive erosion of the margins and the development of deep subaerial canyons; (3) the accumulation of the product of the erosion in the downslope domain of the margins; (4) the deposition of thick evaporites (up to 3000 m thick) above the deep Mediterranean abyssal plains and (5) and a very rapid refilling of the Mediterranean basin during the Latest Miocene/Lower Pliocene, following the re-connection between Atlantic and Mediterranean through the Gibraltar straight. Timing, causes and chronology of the MSC are not yet fully understood, but different scenarii have been proposed to explain in details the modalities of this catastrophic event. Certainly, the ongoing discussion about not fully conclusive interpretations are mainly linked to the fact that so far, only the deepest and buried Mediterranean basins might offer the most complete sequence from the Messinian to the Quaternary. Anywhere else, the MSC mostly generated a sedimentary/time lag corresponding to a widespread erosion surface extending from onshore down to the lower slopes of the margins. Onland, Messinian outcrops (e.g. Morocco, Cyprus, Spain, Italy…) are all incomplete and pre-date the drawdown phase and/or are tectonically/geometrically disconnected from the deep basin sequence. Correlations with the offshore depositional units are thus complex, preventing the construction of a coherent scenario of the MSC linking the outcropping evaporites, the erosion of the margins, and the deposition of clastics and deep evaporites in the abyssal plains. The discovery of the Messinian evaporites in the Mediterranenan is probably one of the major achievements of the DSDP program. Unfortunately, the Joides Resolution never drilled through evaporites because of technical impossibility (non-riser drilling vessel). Only the upper few meters of the pinch out of the deep basin sequence has been recovered. Thus, all hypothesis are based on onland outcropping evaporites and offshore seismic data interpretations. Improved quality of seismic data allowed some important advances in the recognition and understanding of Messinian markers (erosion surfaces, depositional units and bounding surfaces) but without the recovery of the full succession, all interpretations lack lithological and stratigraphical calibrations. At present, several basic questions are still open: - What are the true nature of the deep basin depositional units? What are their ages and chronologies? - What was the water depth before, during and after halite deposition in the deep basin? Did the basin(s) completely dried out? What are the associated amplitude and dynamics of the base-level changes? - Did the desiccation impact the regional climate and river run-off? What about climatic variability during the drawdown phase? - What was the balance between erosion and sedimentation during the crisis? What are the vertical movements (tectonic/isostatic responses) associated to margin unloading and basin loading? - What are the present-day fluid dynamics related to the salt layer? Their impact on the deep biosphere? The response to all of these questions would only come from drilling through the complete Messinian succession. It would represent an outstanding opportunity to unravel the history of extreme environmental changes during the Messinian and a unique chance to constrain the age, nature and paleo-environment of deposition of the deep-basin Messinian sequence. For that reason, in the framework of the IODP drilling program, we propose to sample and log two different sites in the western and eastern Mediterranean basins, with the new scientific riser drillship Chikyu perfectly adapted to overcome all safety problems. In order to promote a continuous sedimentary record of the MSC since the pre-crisis paleo-environmental changes, the sites should be drilled in areas where the Messinian salt is tabular and exempted of significant tectonic influence. A complete set of integrated studies (sedimentology, geochemistry, micropaleontology, bio-and cyclostratigraphy) should be carried out. This project opens the perspective of a new intellectual and scientific adventure that we expect to be as rich and exciting as the discovery of this unusual event was.

View of Spacelab module in payload bay with Earth background

NASA Image and Video Library

2016-08-12

STS083-709-030 (4-8 April 1997) --- Panorama over the Nile River, Sinai Peninsula and the Red Sea. Looking past the Orbiter's tail, this view extends from central Egypt eastward to Saudi Arabia on the horizon. Two major water systems, seen in this view, the Nile River and the Red Sea are used for world commerce and transportation in this region. The Nile is flanked immediately by agriculture then beyond by desert. This emphasizes the importance of the river waters to sustain a thriving local population. The Nile River delta is north under the clouds on the upper left-hand corner of the photo. Geologically, the Red Sea is a spreading center between the Arabian and the African Plates, and will continue to widen slowly over a long period of time.

A fluorogenic probe for SNAP-tagged plasma membrane proteins based on the solvatochromic molecule Nile Red.

PubMed

Prifti, Efthymia; Reymond, Luc; Umebayashi, Miwa; Hovius, Ruud; Riezman, Howard; Johnsson, Kai

2014-03-21

A fluorogenic probe for plasma membrane proteins based on the dye Nile Red and SNAP-tag is introduced. It takes advantage of Nile Red, a solvatochromic molecule highly fluorescent in an apolar environment, such as cellular membranes, but almost dark in a polar aqueous environment. The probe possesses a tuned affinity for membranes allowing its Nile Red moiety to insert into the lipid bilayer of the plasma membrane, becoming fluorescent, only after its conjugation to a SNAP-tagged plasma membrane protein. The fluorogenic character of the probe was demonstrated for different SNAP-tag fusion proteins, including the human insulin receptor. This work introduces a new approach for generating a powerful turn-on probe for "no-wash" labeling of plasma membrane proteins with numerous applications in bioimaging.

The White Nile sedimentary system

NASA Astrophysics Data System (ADS)

Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Resentini, Alberto; Vezzoli, Giovanni; Villa, Igor

2014-05-01

The Nile River flows for ~6700 km from south of the Equator to finally reach the Mediterranean Sea at northern subtropical latitudes (Woodward et al. 2007). This is the longest sedimentological laboratory on Earth, a unique setting in which we are investigating changes in sediment composition associated with diverse chemical and physical processes, including weathering and hydraulic sorting. The present study focuses on the southern branch of the Nile across 20° of latitude, from hyperhumid Burundi and Rwanda highlands in central Africa to Khartoum, the capital city of Sudan at the southern edge of the Sahara. Our study of the Kagera basin emphasizes the importance of weathering in soils at the source rather than during stepwise transport, and shows that the transformation of parent rocks into quartzose sand may be completed in one sedimentary cycle (Garzanti et al. 2013a). Micas and heavy minerals, less effectively diluted by recycling than main framework components, offer the best key to identify the original source-rock imprint. The different behaviour of chemical indices such as the CIA (a truer indicator of weathering) and the WIP (markedly affected by quartz dilution) helps us to distinguish strongly weathered first-cycle versus polycyclic quartz sands (Garzanti et al. 2013b). Because sediment is efficiently trapped in East African Rift lakes, the composition of Nile sediments changes repeatedly northwards across Uganda. Downstream of both Lake Kyoga and Lake Albert, quartzose sands are progressively enriched in metamorphiclastic detritus supplied from tributaries draining amphibolite-facies basements. The evolution of White Nile sediments across South Sudan, a scarcely accessible region that suffered decades of civil war, was inferred from the available information (Shukri 1950), integrated by original petrographic, heavy-mineral and geochemical data (Padoan et al. 2011). Mineralogical and isotopic signatures of Bahr-el-Jebel and Sobat sediments, derived respectively from Archean gneisses of Uganda and Neoproterozoic basements of Ethiopia, become gradually homogenized and enriched in quartz, and remain finally unchanged down to Khartoum. This suggests massive sediment dumping in the Sudd and Machar Marshes, and explains why White Nile sediment contribution to the main Nile is negligible (Garzanti et al. 2006). REFERENCES Garzanti E., Andò S., Vezzoli G., Megid A.A.A., El Kammar A., 2006. Petrology of Nile River sands (Ethiopian and Sudan): sediment budgets and erosion patterns. EPSL 252:327-341. Garzanti E., Padoan M., Setti M., Peruta L., Najman Y., Villa I.M., 2013. Weathering geochemistry and Sr-Nd fingerprints of equatorial upper Nile and Congo muds. Geochem. Geophys. Geosyst. 14:292-316. Garzanti E., Padoan M., Andò S., Resentini A., Vezzoli G., Lustrino M., 2013. Weathering and relative durability of detrital minerals in equatorial climate: sand petrology and geochemistry in the East African Rift. J.Geol. 121:547-580. Padoan M., Garzanti E., Harlavan Y., Villa I.M., 2011. Tracing Nile sediment sources by Sr and Nd isotope signatures (Uganda, Ethiopia, Sudan). Geochim. Cosmochim. Acta 75:3627-3644. Shukri N.M., 1950. The mineralogy of some Nile sediments. Quart. J. Geol. Soc. London 105:511-534. Woodward J.C., Macklin M.G., Krom M.D., Williams M.A.J. 2007. The Nile: Evolution, quaternary river environments and material fluxes. In: Large Rivers, Avijit Gupta (Ed.), Wiley, 261-292.

The Middle Jurassic basinal deposits of the Surmeh Formation in the Central Zagros Mountains, southwest Iran: Facies, sequence stratigraphy, and controls

USGS Publications Warehouse

Lasemi, Y.; Jalilian, A.H.

2010-01-01

The lower part of the Lower to Upper Jurassic Surmeh Formation consists of a succession of shallow marine carbonates (Toarcian-Aalenian) overlain by a deep marine basinal succession (Aalenian-Bajocian) that grades upward to Middle to Upper Jurassic platform carbonates. The termination of shallow marine carbonate deposition of the lower part of the Surmeh Formation and the establishment of deep marine sedimentation indicate a change in the style of sedimentation in the Neotethys passive margin of southwest Iran during the Middle Jurassic. To evaluate the reasons for this change and to assess the basin configuration during the Middle Jurassic, this study focuses on facies analysis and sequence stratigraphy of the basinal deposits (pelagic and calciturbidite facies) of the Surmeh Formation, referred here as 'lower shaley unit' in the Central Zagros region. The upper Aalenian-Bajocian 'lower shaley unit' overlies, with an abrupt contact, the Toarcian-lower Aalenian platform carbonates. It consists of pelagic (calcareous shale and limestone) and calciturbidite facies grading to upper Bajocian-Bathonian platform carbonates. Calciturbidite deposits in the 'lower shaley unit' consist of various graded grainstone to lime mudstone facies containing mixed deep marine fauna and platform-derived material. These facies include quartz-bearing lithoclast/intraclast grainstone to lime mudstone, bioclast/ooid/peloid intraclast grainstone, ooid grainstone to packstone, and lime wackestone to mudstone. The calciturbidite layers are erosive-based and commonly exhibit graded bedding, incomplete Bouma turbidite sequence, flute casts, and load casts. They consist chiefly of platform-derived materials including ooids, intraclasts/lithoclasts, peloids, echinoderms, brachiopods, bivalves, and open-ocean biota, such as planktonic bivalves, crinoids, coccoliths, foraminifers, and sponge spicules. The 'lower shaley unit' constitutes the late transgressive and the main part of the highstand systems tract of a depositional sequence and grades upward to platform margin and platform interior facies as a result of late highstand basinward progradation. The sedimentary record of the 'lower shaley unit' in the Central Zagros region reveals the existence of a northwest-southeast trending platform margin during the Middle Jurassic that faced a deep basin, the 'Pars intrashelf basin' in the northeast. The thinning of calciturbidite layers towards the northeast and the widespread Middle Jurassic platform carbonates in the southern Persian Gulf states and in the Persian Gulf area support the existence of a southwest platform margin and platform interior source area. The platform margin was formed as a result of tectonic activity along the preexisting Mountain Front fault associated with Cimmerian continental rifting in northeast Gondwana. Flooding of the southwest platform margin during early to middle Bajocian resulted in the reestablishment of the carbonate sediment factory and overproduction of shallow marine carbonates associated with sea-level highstand, which led to vertical and lateral expansion of the platform and gradual infilling of the Pars intrashelf basin by late Bajocian time. ?? 2010 Springer-Verlag.

Space Radar Image of Sudan Collision Zone

NASA Technical Reports Server (NTRS)

1994-01-01

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.

Regional and sediment depth differences in nematode community structure greater than between habitats on the New Zealand margin: Implications for vulnerability to anthropogenic disturbance

NASA Astrophysics Data System (ADS)

Rosli, Norliana; Leduc, Daniel; Rowden, Ashley A.; Probert, P. Keith; Clark, Malcolm R.

2018-01-01

Deep-sea community attributes vary at a range of spatial scales. However, identifying the scale at which environmental factors affect variability in deep-sea communities remains difficult, as few studies have been designed in such a way as to allow meaningful comparisons across more than two spatial scales. In the present study, we investigated nematode diversity, community structure and trophic structure at different spatial scales (sediment depth (cm), habitat (seamount, canyon, continental slope; 1-100 km), and geographic region (100-10000 km)), while accounting for the effects of water depth, in two regions on New Zealand's continental margin. The greatest variability in community attributes was found between sediment depth layers and between regions, which explained 2-4 times more variability than habitats. The effect of habitat was consistently stronger in the Hikurangi Margin than the Bay of Plenty for all community attributes, whereas the opposite pattern was found in the Bay of Plenty where effect of sediment depth was greater in Bay of Plenty. The different patterns at each scale in each region reflect the differences in the environmental variables between regions that control nematode community attributes. Analyses suggest that nematode communities are mostly influenced by sediment characteristics and food availability, but that disturbance (fishing activity and bioturbation) also accounts for some of the observed patterns. The results provide new insight on the relative importance of processes operating at different spatial scales in regulating nematode communities in the deep-sea, and indicate potential differences in vulnerability to anthropogenic disturbance.

Partitioning of deformation along a reactivated rifted margin: example of the northern Ligurian margin.

NASA Astrophysics Data System (ADS)

Sage, Françoise; Beslier, Marie-Odile; Gaullier, Virginie; Larroque, Christophe; Dessa, Jean-Xavier; Mercier de Lepinay, Bernard; Corradi, Nicola; Migeon, Sébastien; Katz, Hélène; Ruiz Constan, Ana

2013-04-01

The northern Ligurian margin, of Oligo-Miocene age, is currently undergoing compression related to microplate motions and/or to gravity spreading of the Alpine chain located immediately north of it. Active thrust faults and folds have previously been identified below the margin, together with a global uplift of the continental edge, since at least the Messinian. The seismicity that goes with the present-day margin contraction (e.g. Mw 6.9, 1887/02/23) extends to the axis of the adjacent oceanic basin (e.g. ML 6.0, 1963/07/19; ML 5.4, 2011/07/07). However, we do not know of any recent or active crustal contractional structure within this oceanic domain. In this study, we use new 12-channel high-resolution seismic data (FABLES seismic cruise, 2012, R/V Tethys II) in order to image the sedimentary cover of the Ligurian oceanic basin, up to ~3km below the seabed, including the Plio-Quaternary and the Messinian sediment down to the bottom of the Messinian salt layer. Because the Messinian event is well dated (5.96-5.32 Ma) and well identified in the seismic data, it forms a clear marker that we use to characterize the recent deformation related to both mobile salt motion and crustal tectonics. About 50 km south of the margin offshore of Italy, we identify huge and complex salt walls that elongate SW-NE. Such salt walls, which cannot be explained by salt tectonics only, are interpreted as evidence of deep-seated crustal deformation. They form en echelon structures that are well expressed in the seabed morphology, and do not correspond to any significant vertical throw at the base of the salt layer. This suggests that within the deep basin, mainly strike-slip faulting accommodates long-term crustal deformation. It thus offers a contrast with the margin where deformation is mainly marked by shortening and reverse faulting, with vertical throws of several hundred meters. This discrepancy in the tectonic styles between the margin and the adjacent oceanic basin suggests some partitioning of the deformation. It may result from the difference in the topographic gradient of the main crustal interfaces between the steep margin and the adjacent oceanic domain, and/or to different mechanical behaviours of the adjacent lithospheric domains.

Nile River Delta, Egypt

NASA Technical Reports Server (NTRS)

1984-01-01

The Nile River Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population. The capital city of Cairo is at the apex of the delta. Just across the river from Cairo can be seen the ancient three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

Nile Delta, Egypt

NASA Technical Reports Server (NTRS)

1982-01-01

The Nile Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population of 57 million. The capital city of Cairo is at the apex of the delta in the middle of the scene. Across the river from Cairo can be seen the three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

Nile River Delta, Egypt

NASA Image and Video Library

1984-10-13

The Nile River Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population. The capital city of Cairo is at the apex of the delta. Just across the river from Cairo can be seen the ancient three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

Organic-rich sediments in ventilated deep-sea environments: Relationship to climate, sea level, and trophic changes

NASA Astrophysics Data System (ADS)

Bertrand, P.; Pedersen, T. F.; Schneider, R.; Shimmield, G.; Lallier-Verges, E.; Disnar, J. R.; Massias, D.; Villanueva, J.; Tribovillard, N.; Huc, A. Y.; Giraud, X.; Pierre, C.; VéNec-Peyré, M.-T.

2003-02-01

Sediments on the Namibian Margin in the SE Atlantic between water depths of ˜1000 and ˜3600 m are highly enriched in hydrocarbon-prone organic matter. Such sedimentation has occurred for more than 2 million years and is geographically distributed over hundreds of kilometers along the margin, so that the sediments of this region contain a huge concentrated stock of organic carbon. It is shown here that most of the variability in organic content is due to relative dilution by buried carbonates. This reflects both export productivity and diagenetic dissolution, not differences in either water column or bottom water anoxia and related enhanced preservation of organic matter. These observations offer a new mechanism for the formation of potential source rocks in a well-ventilated open ocean, in this case the South Atlantic. The organic richness is discussed in terms of a suite of probable controls including local wind-driven productivity (upwelling), trophic conditions, transfer efficiency, diagenetic processes, and climate-related sea level and deep circulation. The probability of past occurrences of such organic-rich facies in equivalent oceanographic settings at the edge of large oceanic basins should be carefully considered in deep offshore exploration.

Deep sub-seafloor prokaryotes stimulated at interfaces over geological time.

PubMed

Parkes, R John; Webster, Gordon; Cragg, Barry A; Weightman, Andrew J; Newberry, Carole J; Ferdelman, Timothy G; Kallmeyer, Jens; Jørgensen, Bo B; Aiello, Ivano W; Fry, John C

2005-07-21

The sub-seafloor biosphere is the largest prokaryotic habitat on Earth but also a habitat with the lowest metabolic rates. Modelled activity rates are very low, indicating that most prokaryotes may be inactive or have extraordinarily slow metabolism. Here we present results from two Pacific Ocean sites, margin and open ocean, both of which have deep, subsurface stimulation of prokaryotic processes associated with geochemical and/or sedimentary interfaces. At 90 m depth in the margin site, stimulation was such that prokaryote numbers were higher (about 13-fold) and activity rates higher than or similar to near-surface values. Analysis of high-molecular-mass DNA confirmed the presence of viable prokaryotes and showed changes in biodiversity with depth that were coupled to geochemistry, including a marked community change at the 90-m interface. At the open ocean site, increases in numbers of prokaryotes at depth were more restricted but also corresponded to increased activity; however, this time they were associated with repeating layers of diatom-rich sediments (about 9 Myr old). These results show that deep sedimentary prokaryotes can have high activity, have changing diversity associated with interfaces and are active over geological timescales.

Deep-sea Lebensspuren of the Australian continental margins

NASA Astrophysics Data System (ADS)

Przeslawski, Rachel; Dundas, Kate; Radke, Lynda; Anderson, Tara J.

Much of the deep sea comprises soft-sediment habitats dominated by comparatively low abundances of species-rich macrofauna and meiofauna. Although often not observed, these animals bioturbate the sediment during feeding and burrowing, leaving signs of their activities called Lebensspuren ('life traces'). In this study, we use still images to quantify Lebensspuren from the eastern (1921 images, 13 stations, 1300-2200 m depth) and western (1008 images, 11 stations, 1500-4400 m depth) Australian margins using a univariate measure of trace richness and a multivariate measure of Lebensspuren assemblages. A total of 46 Lebensspuren types were identified, including those matching named trace fossils and modern Lebensspuren found elsewhere in the world. Most traces could be associated with waste, crawling, dwellings, organism tests, feeding, or resting, but the origin of 15% of trace types remains unknown. Assemblages were significantly different between the two regions and depth profiles, with five Lebensspuren types accounting for over 95% of the differentiation (ovoid pinnate trace, crater row, spider trace, matchstick trace, mesh trace). Lebensspuren richness showed no strong relationships with depth, total organic carbon, or mud, although there was a positive correlation to chlorin index (i.e., organic freshness) in the eastern margin, with richness increasing with organic freshness. Lebensspuren richness was not related to epifauna either, indicating that epifauna may not be the primary source of Lebensspuren. Despite the abundance and distinctiveness of several traces both in the current and previous studies (e.g., ovoid pinnate, mesh, spider), their origin and distribution remains a mystery. We discuss this and several other considerations in the identification and quantification of Lebensspuren. This study represents the first comprehensive catalogue of deep-sea Lebensspuren in Australian waters and highlights the potential of Lebensspuren as valuable and often untapped deep-sea datasets that can be used for biogeographical, evolutionary, behavioural, and ecological studies.

Another bipolar deep-sea anemone: new species of Iosactis (Actiniaria, Endomyaria) from Antarctica

NASA Astrophysics Data System (ADS)

Rodríguez, Estefanía

2012-06-01

A new species of deep-sea burrowing sea anemone is described and illustrated from Antarctica. Iosactis antarctica sp. nov. is characterised by easily deciduous tentacles with sphincters in the base, smooth column, endodermal marginal sphincter, same mesenteries proximally and distally, 24 perfect mesenteries regularly arranged, diffuse retractor musculature and basilar muscles well developed. Iosactis antarctica sp. nov. is the second species of the deep-sea abyssal genus Iosactis; it differs from I. vagabunda in internal anatomy, cnidae and geographic distribution. The description of I. antarctica sp. nov. provides the opportunity to revaluate the morphology of the proximal end of this genus.

The Deep-Sea Microbial Community from the Amazonian Basin Associated with Oil Degradation.

PubMed

Campeão, Mariana E; Reis, Luciana; Leomil, Luciana; de Oliveira, Louisi; Otsuki, Koko; Gardinali, Piero; Pelz, Oliver; Valle, Rogerio; Thompson, Fabiano L; Thompson, Cristiane C

2017-01-01

One consequence of oil production is the possibility of unplanned accidental oil spills; therefore, it is important to evaluate the potential of indigenous microorganisms (both prokaryotes and eukaryotes) from different oceanic basins to degrade oil. The aim of this study was to characterize the microbial response during the biodegradation process of Brazilian crude oil, both with and without the addition of the dispersant Corexit 9500, using deep-sea water samples from the Amazon equatorial margin basins, Foz do Amazonas and Barreirinhas, in the dark and at low temperatures (4°C). We collected deep-sea samples in the field (about 2570 m below the sea surface), transported the samples back to the laboratory under controlled environmental conditions (5°C in the dark) and subsequently performed two laboratory biodegradation experiments that used metagenomics supported by classical microbiological methods and chemical analysis to elucidate both taxonomic and functional microbial diversity. We also analyzed several physical-chemical and biological parameters related to oil biodegradation. The concomitant depletion of dissolved oxygen levels, oil droplet density characteristic to oil biodegradation, and BTEX concentration with an increase in microbial counts revealed that oil can be degraded by the autochthonous deep-sea microbial communities. Indigenous bacteria (e.g., Alteromonadaceae, Colwelliaceae , and Alcanivoracaceae ), archaea (e.g., Halobacteriaceae, Desulfurococcaceae , and Methanobacteriaceae ), and eukaryotic microbes (e.g., Microsporidia, Ascomycota, and Basidiomycota) from the Amazonian margin deep-sea water were involved in biodegradation of Brazilian crude oil within less than 48-days in both treatments, with and without dispersant, possibly transforming oil into microbial biomass that may fuel the marine food web.

The Deep-Sea Microbial Community from the Amazonian Basin Associated with Oil Degradation

PubMed Central

Campeão, Mariana E.; Reis, Luciana; Leomil, Luciana; de Oliveira, Louisi; Otsuki, Koko; Gardinali, Piero; Pelz, Oliver; Valle, Rogerio; Thompson, Fabiano L.; Thompson, Cristiane C.

2017-01-01

One consequence of oil production is the possibility of unplanned accidental oil spills; therefore, it is important to evaluate the potential of indigenous microorganisms (both prokaryotes and eukaryotes) from different oceanic basins to degrade oil. The aim of this study was to characterize the microbial response during the biodegradation process of Brazilian crude oil, both with and without the addition of the dispersant Corexit 9500, using deep-sea water samples from the Amazon equatorial margin basins, Foz do Amazonas and Barreirinhas, in the dark and at low temperatures (4°C). We collected deep-sea samples in the field (about 2570 m below the sea surface), transported the samples back to the laboratory under controlled environmental conditions (5°C in the dark) and subsequently performed two laboratory biodegradation experiments that used metagenomics supported by classical microbiological methods and chemical analysis to elucidate both taxonomic and functional microbial diversity. We also analyzed several physical–chemical and biological parameters related to oil biodegradation. The concomitant depletion of dissolved oxygen levels, oil droplet density characteristic to oil biodegradation, and BTEX concentration with an increase in microbial counts revealed that oil can be degraded by the autochthonous deep-sea microbial communities. Indigenous bacteria (e.g., Alteromonadaceae, Colwelliaceae, and Alcanivoracaceae), archaea (e.g., Halobacteriaceae, Desulfurococcaceae, and Methanobacteriaceae), and eukaryotic microbes (e.g., Microsporidia, Ascomycota, and Basidiomycota) from the Amazonian margin deep-sea water were involved in biodegradation of Brazilian crude oil within less than 48-days in both treatments, with and without dispersant, possibly transforming oil into microbial biomass that may fuel the marine food web. PMID:28659874

Well-circumscribed deep-seated lipomas of the upper extremity. A report of 13 cases.

PubMed

Elbardouni, A; Kharmaz, M; Salah Berrada, M; Mahfoud, M; Elyaacoubi, M

2011-04-01

The purpose of this study is to determine if giant size is of bad prognosis in deep lipomas of the upper extremity. We report a retrospective study of 13 patients with deep-seated lipomas of the upper extremity treated during the period from April 1997 to April 2008. We evaluated the clinical and radiological characteristics, treatment and evolution profile of these patients. There were 10 women and three men, with an average age of 53 years (range 30-79 years). Seven of these lipomas were in the arm, one in the shoulder, and five in the forearm. Six lipomas were intramuscular, six intermuscular (three of them being attached to bone and labelled parosteal lipoma) and one epivaginal lipoma of the flexor tendon sheath. All patients presented a progressive slow-growing mass that was associated with radial paralysis in one case and carpal tunnel syndrome in one case. Plain radiographs showed a radiolucent soft-tissue image in all cases and an associated osteochondroma in one parosteal lipoma. Computer tomography (CT) or magnetic resonance imaging (MRI) suggested the lipomatous nature and benign characteristics of these deep lipomas that were giant in all cases (mean size: 7 cm). Lipoma marginal excision was performed and histopathological examination demonstrated features consistent with a benign lipoma. There was good function and no clinical recurrence was observed after a mean follow-up of three years. Giant deep-seated lipomas of the upper extremity are uncommon and can be intermuscular or intramuscular. A painless soft-tissue mass is the most frequent chief complaint. MRI with fat suppression suggests the diagnosis and studies the extension of deep lipoma. Marginal excision is the treatment of choice and histopathology eliminates diagnosis of well-differentiated liposarcoma. Appropriate evaluation of deep lipoma is to rule out malignancy by systematically performing MRI and biopsy. In contrast to deep-seated lipomas of the lower extremity or the retroperitoneal space, the prognosis of deep-seated lipomas of the upper extremity is good irrelevant of their size. Recurrence and the degeneration are very rare. Level 4. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Comparison of authigenic carbonates formation at mud volcanoes and pockmarks in the Portuguese Margin vs. at the Yinazao serpentinite mud volcano in the Marianas forearc

NASA Astrophysics Data System (ADS)

Magalhaes, V. H.; Freitas, M.; Azevedo, M. R.; Pinheiro, L. M.; Salgueiro, E.; Abrantes, F. F. G.

2017-12-01

On the Portuguese passive continental margin, active and past seepage processes form mud volcanoes and pockmarks at the seafloor. Often associated with these structures are extensive methane-derived authigenic carbonates that form from deep-sourced methane-rich fluids that ascend from deep to the upper sedimentary column and often discharge at the seafloor. These carbonates form within the sediments and are either dominated by dolomite and high-Mg calcites, when formed under a restricted seawater circulation environment, anoxic and low sulphate conditions; or by aragonite and calcite when formed close to or at the seafloor in a high sulphate system. The δ13C values (-56.2‰ VPDB) found on the carbonate-cemented material clearly indicates methane as the major carbon source. On the Yinazao serpentinite mud volcano at an active, non-accretionary, convergent margin, sediment samples from IODP Sites U1491 and U1492 (Exp. 366) contain authigenic minerals such as aragonite, calcite, brucite, gypsum among others. Authigenic aragonite occurs predominantly within the top meters of the cores where both oxidation and seawater circulation in the sedimentary column are higher. In this system, initial results indicate that the major carbon source is most probably not methane but seawater related. This work discusses and compares the major carbon sources in both systems: sedimentary mud volcanoes and pockmarks of a passive margin vs. a serpentinite mud volcano of an active, non-accretionary, convergent margin. We acknowledge the support from the PES project - Pockmarks and fluid seepage in the Estremadura Spur: implications for regional geology, biology, and petroleum systems (PTDC/GEOFIQ/5162/2014) financed by the Portuguese Foundation for Science and Technology (FCT).

A viscoplastic shear-zone model for deep (15-50 km) slow-slip events at plate convergent margins

NASA Astrophysics Data System (ADS)

Yin, An; Xie, Zhoumin; Meng, Lingsen

2018-06-01

A key issue in understanding the physics of deep (15-50 km) slow-slip events (D-SSE) at plate convergent margins is how their initially unstable motion becomes stabilized. Here we address this issue by quantifying a rate-strengthening mechanism using a viscoplastic shear-zone model inspired by recent advances in field observations and laboratory experiments. The well-established segmentation of slip modes in the downdip direction of a subduction shear zone allows discretization of an interseismic forearc system into the (1) frontal segment bounded by an interseismically locked megathrust, (2) middle segment bounded by episodically locked and unlocked viscoplastic shear zone, and (3) interior segment that slips freely. The three segments are assumed to be linked laterally by two springs that tighten with time, and the increasing elastic stress due to spring tightening eventually leads to plastic failure and initial viscous shear. This simplification leads to seven key model parameters that dictate a wide range of mechanical behaviors of an idealized convergent margin. Specifically, the viscoplastic rheology requires the initially unstable sliding to be terminated nearly instantaneously at a characteristic velocity, which is followed by stable sliding (i.e., slow-slip). The characteristic velocity, which is on the order of <10-7 m/s for the convergent margins examined in this study, depends on the (1) effective coefficient of friction, (2) thickness, (3) depth, and (4) viscosity of the viscoplastic shear zone. As viscosity decreases exponentially with temperature, our model predicts faster slow-slip rates, shorter slow-slip durations, more frequent slow-slip occurrences, and larger slow-slip magnitudes at warmer convergent margins.

An integrated geophysical study on the Mesozoic strata distribution and hydrocarbon potential in the South China Sea

NASA Astrophysics Data System (ADS)

Hu, Weijian; Hao, Tianyao; Jiang, Weiwei; Xu, Ya; Zhao, Baimin; Jiang, Didi

2015-11-01

A series of drilling, dredge, and seismic investigations indicate that Mesozoic sediments exist in the South China Sea (SCS) which shows a bright prospect for oil and gas exploration. In order to study the distribution of Mesozoic strata and their residual thicknesses in the SCS, we carried out an integrated geophysical study based mainly on gravity data, gravity basement depth and distribution of residual Mesozoic thickness in the SCS were obtained using gravity inversion constrained with high-precision drilling and seismic data. In addition, the fine deep crustal structures and distribution characteristics of Mesozoic thicknesses of three typical profiles were obtained by gravity fitting inversion. Mesozoic strata in the SCS are mainly distributed in the south and north continental margins, and have been reformed by the later tectonic activities. They extend in NE-trending stripes are macro-controlled by the deep and large NE-trending faults, and cut by the NW-trending faults which were active in later times. The offset in NW direction of Mesozoic strata in Nansha area of the southern margin are more obvious as compared to the north margin. In the Pearl River Mouth Basin and Southwest Taiwan Basin of the north continental margin the Mesozoic sediments are continuously distributed with a relatively large thickness. In the Nansha area of the south margin the Mesozoic strata are discontinuous and their thicknesses vary considerably. According to the characteristics of Mesozoic thickness distribution and hydrocarbon potential analyses from drilling and other data, Dongsha Uplift-Chaoshan Depression, Southwest Taiwan Basin-Peikang Uplift and Liyue Bank have large thickness of the Mesozoic residual strata, have good hydrocarbon genesis capability and complete source-reservoir-cap combinations, show a bright prospect of Mesozoic oil/gas resources.

The modern Nile sediment system: Processes and products

NASA Astrophysics Data System (ADS)

Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Vezzoli, Giovanni; El Kammar, Ahmed

2015-12-01

We trace compositional changes of Nile sediments for 7400 km, from their sources in equatorial rift highlands of Burundi and Rwanda to their sink in the Mediterranean Sea. All chemical and physical controls on sediment petrography, mineralogy and geochemistry, including weathering, grain-size, hydraulic sorting, mechanical breakdown, anthropic impact, mixing and recycling are investigated in detail. The Nile course is controlled along its entire length by the East African-Red Sea Rift. In this anorogenic setting, detritus is derived in various proportions from volcanic fields associated with tectonic extension (Anorogenic Volcanic provenance) and from igneous, metamorphic and sedimentary rocks uplifted on the rift shoulders or exposed on the craton (Continental Block provenance). The entire spectrum of such detrital signatures is displayed in the Nile catchment. Volcaniclastic Atbara sand is generated by focused erosion of the Ethiopian basaltic plateau in semiarid climate, whereas quartzose White Nile sand reflects low erosion rates, extensive weathering and sediment trapping in lakes and swamps at equatorial to subequatorial latitudes. In the main Nile, as in its main tributary the Blue Nile, suspended load is volcaniclastic, whereas feldspatho-quartzose bedload is derived largely from basement sources, with fine to medium-grained eolian sand added along the lower course. Mixing of detrital populations with different provenance and grain size is reflected in diverse violations of settling-equivalence relationships in fluvial and deltaic sediments. Sediment delivery from Sudan has been cut off after closure of the Aswan High Dam and accelerated erosion of deltaic cusps is leading to local formation of placer lags dominated by ultradense Fe-Ti-Cr oxides, but mineralogical changes caused by man's radical modification of fluvial regimes have been minor so far. In beaches of Sinai, Gaza and Israel, the Nile volcaniclastic trace gets progressively diluted by quartzose sand recycled from eolian coastal deposits and carbonaticlastic detritus eroded from the Levant rift shoulder. Studying the compositional variability of modern sediments in big-river systems allows us to appreciate the richness of natural processes occurring in the vast drainage basin, and provides us with a key to understand the information stored in sedimentary archives and to reconstruct the evolution of the Earth's surface from the recent to the less recent past.

Prediction of future climate change for the Blue Nile, using RCM nested in GCM

NASA Astrophysics Data System (ADS)

Sayed, E.; Jeuland, M.; Aty, M.

2009-04-01

Although the Nile River Basin is rich in natural resources, it faces many challenges. Rainfall is highly variable across the region, on both seasonal and inter-annual scales. This variability makes the region vulnerable to droughts and floods. Many development projects involving Nile waters are currently underway, or being studied. These projects will lead to land-use patterns changes and water distribution and availability. It is thus important to assess the effects of a) these projects and b) evolving water resource management and policies, on regional hydrological processes. This paper seeks to establish a basis for evaluation of such impacts within the Blue Nile River sub-basin, using the RegCM3 Regional Climate Model to simulate interactions between the land surface and climatic processes. We first present results from application of this RCM model nested with downscaled outputs obtained from the ECHAM5/MPI-OM1 transient simulations for the 20th Century. We then investigate changes associated with mid-21st century emissions forcing of the SRES A1B scenario. The results obtained from the climate model are then fed as inputs to the Nile Forecast System (NFS), a hydrologic distributed rainfall runoff model of the Nile Basin, The interaction between climatic and hydrological processes on the land surface has been fully coupled. Rainfall patterns and evaporation rates have been generated using RegCM3, and the resulting runoff and Blue Nile streamflow patterns have been simulated using the NFS. This paper compares the results obtained from the RegCM3 climate model with observational datasets for precipitation and temperature from the Climate Research Unit (UK) and the NASA Goddard Space Flight Center GPCP (USA) for 1985-2000. The validity of the streamflow predictions from the NFS is assessed using historical gauge records. Finally, we present results from modeling of the A1B emissions scenario of the IPCC for the years 2034-2055. Our results indicate that future changes in rainfall may vary over different areas of the Upper Blue Nile catchment in Ethiopia. Our results suggest that there may be good reasons for developing climate models with finer spatial resolution than the more commonly used GCMs.

Big mantle wedge, anisotropy, slabs and earthquakes beneath the Japan Sea

NASA Astrophysics Data System (ADS)

Zhao, Dapeng

2017-09-01

The Japan Sea is a part of the western Pacific trench-arc-backarc system and has a complex bathymetry and intense seismic activities in the crust and upper mantle. Local seismic tomography revealed strong lateral heterogeneities in the crust and uppermost mantle beneath the eastern margin of the Japan Sea, which was determined using P and S wave arrival times of suboceanic earthquakes relocated precisely with sP depth phases. Ambient-noise tomography revealed a thin crust and a thin lithosphere beneath the Japan Sea and significant low-velocity (low-V) anomalies in the shallow mantle beneath the western and eastern margins of the Japan Sea. Observations with ocean-bottom seismometers and electromagnetometers revealed low-V and high-conductivity anomalies at depths of 200-300 km in the big mantle wedge (BMW) above the subducting Pacific slab, and the anomalies are connected with the low-V zone in the normal mantle wedge beneath NE Japan, suggesting that both shallow and deep slab dehydrations occur and contribute to the arc and back-arc magmatism. The Pacific slab has a simple geometry beneath the Japan Sea, and earthquakes occur actively in the slab down to a depth of ∼600 km beneath the NE Asian margin. Teleseismic P and S wave tomography has revealed that the Philippine Sea plate has subducted aseismically down to the mantle transition zone (MTZ, 410-660 km) depths beneath the southern Japan Sea and the Tsushima Strait, and a slab window is revealed within the aseismic Philippine Sea slab. Seismic anisotropy tomography revealed a NW-SE fast-velocity direction in the BMW, which reflects corner flows induced by the fast deep subduction of the Pacific slab. Large deep earthquakes (M > 7.0; depth > 500 km) occur frequently beneath the Japan Sea western margin, which may be related to the formation of the Changbai and Ulleung intraplate volcanoes. A metastable olivine wedge is revealed within the cold core of the Pacific slab at the MTZ depth, which may be related to the deep seismicity. However, many of these results are still preliminary, due to the lack of seismic stations in the Japan Sea. The key to resolving these critical geoscientific issues is seismic instrumentation in the Japan Sea, for which international cooperation of geoscience communities in the East Asian countries is necessary.

Oligocene to Holocene sediment drifts and bottom currents on the slope of Gabon continental margin (west Africa). Consequences for sedimentation and southeast Atlantic upwelling

NASA Astrophysics Data System (ADS)

Séranne, Michel; Nzé Abeigne, César-Rostand

1999-10-01

Seismic reflection profiles on the slope of the south Gabon continental margin display furrows 2 km wide and some 200 m deep, that develop normal to the margin in 500-1500 m water depth. Furrows are characterised by an aggradation/progradation pattern which leads to margin-parallel, northwestward migration of their axes through time. These structures, previously interpreted as turbidity current channels, display the distinctive seismic image and internal organisation of sediment drifts, constructed by the activity of bottom currents. Sediment drifts were initiated above a major Oligocene unconformity, and they developed within a Oligocene to Present megasequence of general progradation of the margin, whilst they are markedly absent from the underlying Late Cretaceous-Eocene aggradation megasequence. The presence of upslope migrating sediment waves, and the northwest migration of the sediment drifts indicate deposition by bottom current flowing upslope, under the influence of the Coriolis force. Such landwards-directed bottom currents on the slope probably represent coastal upwelling, which has been active along the west Africa margin throughout the Neogene.

Mechanisms underlying the organizer formation in Bufo arenarum embryos.

PubMed

Manes, M E; Nieto, O L

1989-06-01

In the early gastrula of Bufo arenarum the prospective mesoderm was previously identified as a marginal belt of grey cells. To analyze their differentiation capacity explants of these cells were cultured within ectodermal vesicles, in isolation and in combination with vegetal components. When cultured in isolation, dorsal and ventral fragments from the deep marginal zone behaved differently. Whilst ventral explants produced blood cells, dorsal explants failed to differentiate, remaining as masses of yolk-laden cells. On the other hand, both cultures were drastically modified when associated with superficial cells from the blastoporal zone, which caused the following effects: a) Promotion of differentiation in dorsal marginal explants, able now to produce notochordal and somitic structures, in addition to mesenchymatic cells. b) Promotion of dorsalization in ventral marginal explants, which changed their expected destiny developing axial components, similar to those furnished by "activated" dorso marginal explants. On the contrary, combined cultures of animal and vegetal pieces were unable to generate mesodermal structures. These studies suggest that the axial mesoderm, identified as the "organizer", develops from a marginal substrate of genuine mesodermal cells through a dorsalizing inductive stimulus originated in superficial periblastoporal cells.

Evaluation of surgical margins according to the histological type of basal cell carcinoma.

PubMed

Godoy, Charles Antonio Pires de; Neta, Alice Lima de Oliveira; Leão, Sofia Silveira de Souza; Dantas, Raul Lima; Carvalho, Valeska Oliveira Fonseca; Silva, Samuel Freire da

2017-01-01

Basal cell carcinoma is the most common skin cancer in the world. The aim of this study was to evaluate the surgical margin of basal cell carcinoma and correlate this with its histologic subtype. A retrospective analysis of pathology laboratory records from 1990 to 2000 was performed and the following data was collected: age, sex, race, anatomical location, histological type, and state of the excision margins in 1,428 histopathological reports of basal cell carcinoma. Ages ranged from 6 to 99 years, with an average of 57. There was a slight predominance of lesions in white women patients, and the most common histological subtype was the nodular, followed by the superficial. The most common locations were in the head and neck, with highest prevalence appeared in the nose. Surgical margins revealed a lateral involvement of 20.14% and a deep involvement of 12.47%. The fibrosing basal cell carcinoma is the histological type that most often presented positive surgical margins.

Evaluation of the marginal and internal gaps of three different dental prostheses: comparison of the silicone replica technique and three-dimensional superimposition analysis

PubMed Central

2017-01-01

PURPOSE The purposes of this study were to evaluate the marginal and internal gaps, and the potential clinical applications of three different methods of dental prostheses fabrication, and to compare the prostheses prepared using the silicone replica technique (SRT) and those prepared using the three-dimensional superimposition analysis (3DSA). MATERIALS AND METHODS Five Pekkton, lithium disilicate, and zirconia crowns were each manufactured and tested using both the SRT and the two-dimensional section of the 3DSA. The data were analyzed with the nonparametric version of a two-way analysis of variance using rank-transformed values and the Tukey's post-hoc test (α = .05). RESULTS Significant differences were observed between the fabrication methods in the marginal gap (P < .010), deep chamfer (P < .001), axial wall (P < .001), and occlusal area (P < .001). A significant difference in the occlusal area was found between the two measurement methods (P < .030), whereas no significant differences were found in the marginal gap (P > .350), deep chamfer (P > .719), and axial wall (P > .150). As the 3DSA method is three-dimensional, it allows for the measurement of arbitrary points. CONCLUSION All of the three fabrication methods are valid for measuring clinical objectives because they produced prostheses within the clinically acceptable range. Furthermore, a three-dimensional superimposition analysis verification method such as the silicone replica technique is also applicable in clinical settings. PMID:28680546

Biodiversity of the Deep-Sea Continental Margin Bordering the Gulf of Maine (NW Atlantic): Relationships among Sub-Regions and to Shelf Systems

PubMed Central

Kelly, Noreen E.; Shea, Elizabeth K.; Metaxas, Anna; Haedrich, Richard L.; Auster, Peter J.

2010-01-01

Background In contrast to the well-studied continental shelf region of the Gulf of Maine, fundamental questions regarding the diversity, distribution, and abundance of species living in deep-sea habitats along the adjacent continental margin remain unanswered. Lack of such knowledge precludes a greater understanding of the Gulf of Maine ecosystem and limits development of alternatives for conservation and management. Methodology/Principal Findings We use data from the published literature, unpublished studies, museum records and online sources, to: (1) assess the current state of knowledge of species diversity in the deep-sea habitats adjacent to the Gulf of Maine (39–43°N, 63–71°W, 150–3000 m depth); (2) compare patterns of taxonomic diversity and distribution of megafaunal and macrofaunal species among six distinct sub-regions and to the continental shelf; and (3) estimate the amount of unknown diversity in the region. Known diversity for the deep-sea region is 1,671 species; most are narrowly distributed and known to occur within only one sub-region. The number of species varies by sub-region and is directly related to sampling effort occurring within each. Fishes, corals, decapod crustaceans, molluscs, and echinoderms are relatively well known, while most other taxonomic groups are poorly known. Taxonomic diversity decreases with increasing distance from the continental shelf and with changes in benthic topography. Low similarity in faunal composition suggests the deep-sea region harbours faunal communities distinct from those of the continental shelf. Non-parametric estimators of species richness suggest a minimum of 50% of the deep-sea species inventory remains to be discovered. Conclusions/Significance The current state of knowledge of biodiversity in this deep-sea region is rudimentary. Our ability to answer questions is hampered by a lack of sufficient data for many taxonomic groups, which is constrained by sampling biases, life-history characteristics of target species, and the lack of trained taxonomists. PMID:21124960

The deep structure of the Sichuan basin and adjacent orogenic zones revealed by the aggregated deep seismic profiling datum

NASA Astrophysics Data System (ADS)

Xiong, X.; Gao, R.; Li, Q.; Wang, H.

2012-12-01

The sedimentary basin and the orogenic belt are the basic two tectonic units of the continental lithosphere, and form the basin-mountain coupling system, The research of which is the key element to the oil and gas exploration, the global tectonic theory and models and the development of the geological theory. The Sichuan basin and adjacent orogenic belts is one of the most ideal sites to research the issues above, in particular by the recent deep seismic profiling datum. From the 1980s to now, there are 11 deep seismic sounding profiles and 6 deep seismic reflection profiles and massive seismic broadband observation stations deployed around and crossed the Sichuan basin, which provide us a big opportunity to research the deep structure and other forward issues in this region. Supported by the National Natural Science Foundation of China (Grant No. 41104056) and the Fundamental Research Funds of the Institute of Geological Sciences, CAGS (No. J1119), we sampled the Moho depth and low-velocity zone depth and the Pn velocity of these datum, then formed the contour map of the Moho depth and Pn velocity by the interpolation of the sampled datum. The result shows the Moho depth beneath Sichuan basin ranges from 40 to 44 km, the sharp Moho offset appears in the western margin of the Sichuan basin, and there is a subtle Moho depression in the central southern part of the Sichuan basin; the P wave velocity can be 6.0 km/s at ca. 10 km deep, and increases gradually deeper, the average P wave velocity in this region is ca. 6.3 km/s; the Pn velocity is ca. 8.0-8.02 km/s in Sichuan basin, and 7.70-7.76 km/s in Chuan-Dian region; the low velocity zone appears in the western margin of the Sichuan basin, which maybe cause the cause of the earthquake.

Dynamics of particle export on the Northwest Atlantic margin

NASA Astrophysics Data System (ADS)

Hwang, Jeomshik; Manganini, Steven J.; Montluçon, Daniel B.; Eglinton, Timothy I.

2009-10-01

The Northwest Atlantic margin is characterized by high biological productivity in shelf and slope surface waters. In addition to carbon supply to underlying sediments, the persistent, intermediate depth nepheloid layers emanating from the continental shelves, and bottom nepheloid layers maintained by strong bottom currents associated with the southward flowing Deep Western Boundary Current (DWBC), provide conduits for export of organic carbon over the margin and/or to the interior ocean. As a part of a project to understand dynamics of particulate organic carbon (POC) cycling in this region, we examined the bulk and molecular properties of time-series sediment trap samples obtained at 968 m, 1976 m, and 2938 m depths from a bottom-tethered mooring on the New England slope (water depth, 2988 m). Frequent occurrences of higher fluxes in deep relative to shallower sediment traps and low Δ 14C values of sinking POC together provide strong evidence for significant lateral transport of aged organic matter over the margin. Comparison of biogeochemical properties such as aluminum concentration and flux, and iron concentration between samples intercepted at different depths shows that particles collected by the deepest trap had more complex sources than the shallower ones. These data also suggest that at least two modes of lateral transport exist over the New England margin. Based on radiocarbon mass balance, about 30% (±10%) of sinking POC in all sediment traps is estimated to be derived from lateral transport of resuspended sediment. A strong correlation between Δ 14C values and aluminum concentrations suggests that the aged organic matter is associated with lithogenic particles. Our results suggest that lateral transport of organic matter, particularly that resulting from sediment resuspension, should be considered in addition to vertical supply of organic matter derived from primary production, in order to understand carbon cycling and export over continental margins.

Epidemiological and clinical aspects on West Nile virus, a globally emerging pathogen.

PubMed

David, Shoba; Abraham, Asha Mary

2016-08-01

Since the isolation of West Nile virus (WNV) in 1937, in Uganda, it has spread globally, causing significant morbidity and mortality. While birds serve as amplifier hosts, mosquitoes of the Culex genus function as vectors. Humans and horses are dead end hosts. The clinical manifestations of West Nile infection in humans range from asymptomatic illness to West Nile encephalitis. The laboratory offers an array of tests, the preferred method being detection of RNA and serum IgM for WNV, which, if detected, confirms the clinical diagnosis. Although no definitive antiviral therapy and vaccine are available for humans, many approaches are being studied. This article will review the current literature of the natural cycle, geographical distribution, virology, replication cycle, molecular epidemiology, pathogenesis, laboratory diagnosis, clinical manifestations, blood donor screening for WNV, treatment, prevention and vaccines.

West Nile virus: a primer for the otolaryngologist.

PubMed

Michaelson, Peter G; Mair, Eric A

2005-03-01

Since recognition in the United States with a 1999 New York City epidemic, West Nile virus has enduringly migrated westward, leaving few states unaffected. Infection rates are rising at an alarming rate, doubling every year since introduction, with more than 9800 cases in 2003 alone and more than 260 deaths. Patients may present with myriad symptoms including a maculopapular rash that affects the face and trunk and diffuse lymphadenopathy, both of which may result in the initial consultation of the otolaryngologist. We review the clinical history of West Nile virus and its epidemiology, laboratory findings, and variable clinical presentation, with an emphasis on otolaryngologic manifestations. STUDY DESIGN AND SETTING COMPREHENSIVE: review of the literature over the past 50 years with an emphasis on what the present-day otolaryngologist needs to know concerning West Nile virus. Clinical manifestations of the head and neck such as encephalitis, meningitis, maculopapular rash, lymphadenopathy and dysphagia are discussed. To date, there are no articles in the otolaryngology literature discussing West Nile virus. These patients may present initially to multiple providers in diverse specialties because of multifarious initial signs and symptoms. The otolaryngologist must be educated on this quickly growing affliction and practice with a high index of suspicion. In this article we describe the clinical manifestations of West Nile virus, with an emphasis on the otolaryngologic manifestations. The otolaryngologist must become educated about this entity to facilitate preventative measures, adequately treat, and assist other providers in hopeful control and potential eradication of this infectious threat.

Earth observations taken during STS-83 mission

NASA Image and Video Library

2016-08-12

STS083-748-066 (4-8 April 1997) --- Luxor, Qus, and Qina, Egypt on the Nile. The Nile, which is about 4,132 miles long, is the longest river in the world. This photo demonstrates the dependency of the local agriculture on the River. This area is the historic area of ancient Thebes. Luxor, also called EL-AKSUR, or AL-UQSUR, a market town along the southern part of the Nile's curve, is located on the southern half of the ruins of Thebes. Ancient Thebes was about six miles square; the main part of the city was situated along the Nile's east bank; along the west bank was "the city of the dead" -- an area containing the Egyptian kings' mortuary temples and the houses of those priests, soldiers, craftsmen, and laborers who were devoted to their service. Qina, extending 3 - 4 miles (5 - 6 kilometers) on each side of the Nile River between the Arabian and Libyan deserts, is seen on the northeast part of the rivers curve. Occupying the great bend in the Nile Valley, it has an area of 715 square miles (1,851 square kilometers) and contains the celebrated ruins of Thebes and the Valley of the Tombs of the Kings. Qina has a dense agricultural population (more than 3,000 persons per square mile), and most of its land is under basin irrigation, yielding only one crop annually. Main crops are sugar (about three-fifths of the nation's production), lentils, and grains.

Intraoperative narrow band imaging better delineates superficial resection margins during transoral laser microsurgery for early glottic cancer.

PubMed

Garofolo, Sabrina; Piazza, Cesare; Del Bon, Francesca; Mangili, Stefano; Guastini, Luca; Mora, Francesco; Nicolai, Piero; Peretti, Giorgio

2015-04-01

The high rate of positive margins after transoral laser microsurgery (TLM) remains a matter of debate. This study investigates the effect of intraoperative narrow band imaging (NBI) examination on the incidence of positive superficial surgical margins in early glottic cancer treated by TLM. Between January 2012 and October 2013, 82 patients affected by Tis-T1a glottic cancer were treated with TLM by type I or II cordectomies. Intraoperative NBI evaluation was performed using 0-degree and 70-degree rigid telescopes. Surgical specimens were oriented by marking the superior edge with black ink and sent to a dedicated pathologist. Comparison between the rate of positive superficial margins in the present cohort and in a matched historical control group treated in the same way without intraoperative NBI was calculated by chi-square test. At histopathological examination, all surgical margins were negative in 70 patients, whereas 7 had positive deep margins, 2 close, and 3 positive superficial margins. The rate of positive superficial margins was thus 3.6% in the present group and 23.7% in the control cohort (P<.001). Routine use of intraoperative NBI increases the accuracy of neoplastic superficial spreading evaluation during TLM for early glottic cancer. © The Author(s) 2014.

Remote sensing, planform, and facies analysis of the Plain of Tineh, Egypt for the remains of the defunct Pelusiac River

NASA Astrophysics Data System (ADS)

Quintanar, Jessica; Khan, Shuhab D.; Fathy, Mohamed S.; Zalat, Abdel-Fattah A.

2013-11-01

The Pelusiac Branch was a distributary river in the Nile Delta that splits off from the main trunk of the Nile River as it flowed toward the Mediterranean. At approximately 25 A.D., it was chocked by sand and silt deposits from prograding beach accretion processes. The lower course of the river and its bifurcation point from the trunk of the Nile have been hypothesized based on ancient texts and maps, as well as previous research, but results have been inconsistent. Previous studies partly mapped the lower course of the Pelusiac River in the Plain of Tineh, east of the Suez Canal, but rapid urbanization related to the inauguration of the Peace Canal mega-irrigation project has covered any trace of the linear feature reported by these previous studies. The present study used multispectral remote sensing data of GeoEYE-1 and Landsat-TM to locate and accurately map the course of the defunct Pelusiac River within the Plain of Tineh. Remote sensing analysis identified a linear feature that is 135 m wide at its maximum and approximately 13 km long. It extends from the Pelusium ruins to the Suez Canal, just north of the Peace Canal. This remotely located linear feature corresponds to the path of the Pelusiac River during Roman times. Planform geomorphology was applied to determine the hydrological regime and paleodischarge of the river prior to becoming defunct. Planform analysis derived a bankfull paleodischarge value of ~ 5700 m3 s- 1 and an average discharge of 650 m3 s- 1, using the reach average for the interpreted Pelusiac River. The derived values show a river distributary similar in discharge to the modern dammed Damietta river. Field work completed in April of 2012 derived four sedimentary lithofacies of the upper formation on the plain that included pro-delta, delta-front and delta-plain depositional environments. Diatom and fossil mollusk samples were also identified that support coastal beach and lagoonal environments of deposition. Measured section columns and a shoreline parallel transect were also constructed to portray the paleogeography of the Mediterranean coastline in the Plain of Tineh at ~ 25 A.D. and indicate that the sampled study area is the downdrift margin of an asymmetric delta with barrier lagoon systems.

The Transition from Volcanic to Rift Dominated Crustal Breakup - From the Vøring Plateau to the Lofoten Margin, Norway

NASA Astrophysics Data System (ADS)

Breivik, A. J.; Faleide, J. I.; Mjelde, R.; Flueh, E.; Murai, Y.

2017-12-01

The Vøring Plateau was part of the Northeast Atlantic igneous province (NAIP) during early Cenozoic crustal breakup. Crustal breakup at the Vøring Plateau occurred marginal to the deep Cretaceous basins on the shelf, with less extension of the crust. Intrusive magmatism and oceanic crust up to three times normal thickness caused a period of sub-aerial magmatism around breakup time. The transition to the Lofoten Margin is rapid to a deep-water plain. Still, there is some excess magmatism north of this transition, where early oceanic crustal thickness is reduced to half of that of the Vøring Plateau 150 km away. Our estimates of the earliest seafloor spreading rates using new ship-track magnetic profiles on different margin segments offer a clue to what caused this rapid transition. While crustal breakup occurred within the magnetic polarity C24r in other parts of the NAIP, there is a delayed breakup for the Lofoten/Vesterålen margin. Modeling of the earliest seafloor spreading with geomagnetic reversals, indicate a breakup within C24n.3n (anomaly 24b), approximately 1 m.y. later. Both old wide-angle seismic models (from Ocean Bottom Seismometers) off southern Lofoten and a newly published profile farther north show a strongly extended outer margin. Applying early seafloor half-spreading rates ( 30 mm/y) from other NAIP margin segments for 1 m.y. can account for 30 km extra extension, giving a factor of three crustal thinning, and gives a high strain rate of 3.2 ·10-14. Crustal breakup at the magma-poor Iberian Margin occurred at a low strain rate of 4.4·10-15, allowing the ascending mantle to cool, favoring tectonic extension over magmatism. Similar strain rates are found within the main Ethiopian Rift, but there is much magmatism and crustal separation is dominated by dike injection. Mantle tomography models show an exceptionally low seismic velocity below the area interpreted as an unusually hot upper mantle, which will favor magmatism. The transition from the Vøring Plateau to the Lofoten Margin can therefore be explained by the presence/absence of hot mantle plume material under the different segments during rifting. Only after significant extension and close to crustal breakup time did a minor amount of plume material reach the Lofoten/Vesterålen margin to cause some elevated but short-lived excess magmatism there.

Breakup magmatism style on the North Atlantic Igneous Province: insight from Mid-Norwegian volcanic margin

NASA Astrophysics Data System (ADS)

Mansour Abdelmalak, Mohamed; Faleide, Jan Inge; Planke, Sverre; Theissen-Krah, Sonja; Zastrozhnov, Dmitrii; Breivik, Asbjørn Johan; Gernigon, Laurent; Myklebust, Reidun

2014-05-01

The distribution of breakup-related igneous rocks on rifted margins provide important constraints on the magmatic processes during continental extension and lithosphere separation which lead to a better understanding of the melt supply from the upper mantle and the relationship between tectonic setting and volcanism. The results can lead to a better understanding of the processes forming volcanic margins and thermal evolution of associated prospective basins. We present a revised mapping of the breakup-related igneous rocks in the NE Atlantic area, which are mainly based on the Mid-Norwegian (case example) margin. We divided the breakup related igneous rocks into (1) extrusive complexes, (2) shallow intrusive complexes (sills/dykes) and (3) deep intrusive complexes (Lower Crustal Body: LCB). The extrusive complex has been mapped using the seismic volcanostratigraphic method. Several distinct volcanic seismic facies units have been identified. The top basalt reflection is easily identified because of the high impedance contrast between the sedimentary and volcanic rocks resulting in a major reflector. The basal sequence boundary is frequently difficult to identify but it lies usually over the intruded sedimentary basin. Then the base is usually picked above the shallow sill intrusions identified on seismic profile. The mapping of the top and the base of the basaltic sequences allows us to determine the basalt thickness and estimate the volume of the magma production on the Mid- Norwegian margin. The thicker part of the basalt corresponds to the seaward dipping reflector (SDR). The magma feeder system, mainly formed by dyke and sill intrusions, represents the shallow intrusive complex. Deeper interconnected high-velocity sills are also mappable in the margin. Interconnected sill complexes can define continuous magma network >10 km in vertical ascent. The large-scale sill complexes, in addition to dyke swarm intrusions, represent a mode of vertical long-range magma transport through the upper crust. The deep intrusive complex represents the Lower Crustal Body (LCB) which is observed along the margin and characterized by high P-wave velocity bodies (Vp> 7km/s). On the Vøring margin a strong amplitude dome-shaped reflection (the so-called T-Reflection) has been identified and interpreted as the top LCB. In the sedimentary part of the margin, sill intrusions are the major feeder system and seem to be connected with LCB. In the volcanic part of the margin, dykes represent the main feeder system and lie above the thicker part of the LCB.

Is Solar Variability Reflected in the Nile River?

NASA Technical Reports Server (NTRS)

Ruzmaikin, Alexander; Feynman, Joan; Yung, Yuk L.

2006-01-01

We investigate the possibility that solar variability influences North African climate by using annual records of the water level of the Nile collected in 622-1470 A.D. The time series of these records are nonstationary, in that the amplitudes and frequencies of the quasi-periodic variations are time-dependent. We apply the Empirical Mode Decomposition technique especially designed to deal with such time series. We identify two characteristic timescales in the records that may be linked to solar variability: a period of about 88 years and one exceeding 200 years. We show that these timescales are present in the number of auroras reported per decade in the Northern Hemisphere at the same time. The 11-year cycle is seen in the Nile's high-water level variations, but it is damped in the low-water anomalies. We suggest a possible physical link between solar variability and the low-frequency variations of the Nile water level. This link involves the influence of solar variability on the atmospheric Northern Annual Mode and on its North Atlantic Ocean and Indian Ocean patterns that affect the rainfall over the sources of the Nile in eastern equatorial Africa.

Purification and crystallization of dengue and West Nile virus NS2B-NS3 complexes.

PubMed

D'Arcy, Allan; Chaillet, Maxime; Schiering, Nikolaus; Villard, Frederic; Lim, Siew Pheng; Lefeuvre, Peggy; Erbel, Paul

2006-02-01

Both dengue and West Nile virus infections are an increasing risk to humans, not only in tropical and subtropical areas, but also in North America and parts of Europe. These viral infections are generally transmitted by mosquitoes, but may also be tick-borne. Infection usually results in mild flu-like symptoms, but can also cause encephalitis and fatalities. Approximately 2799 severe West Nile virus cases were reported this year in the United States, resulting in 102 fatalities. With this alarming increase in the number of West Nile virus infections in western countries and the fact that dengue virus already affects millions of people per year in tropical and subtropical climates, there is a real need for effective medicines. A possible therapeutic target to combat these viruses is the protease, which is essential for virus replication. In order to provide structural information to help to guide a lead identification and optimization program, crystallizations of the NS2B-NS3 protease complexes from both dengue and West Nile viruses have been initiated. Crystals that diffract to high resolution, suitable for three-dimensional structure determinations, have been obtained.

Does the Nile reflect solar variability?

NASA Astrophysics Data System (ADS)

Ruzmaikin, Alexander; Feynman, Joan; Yung, Yuk

Historical records of the Nile water level provide a unique opportunity to investigate the possibility that solar variability influences the Earth's climate. Particularly important are the annual records of the water level, which are uninterrupted for the years 622-1470 A.D. These records are non-stationary, so that standard spectral analyses cannot adequately characterize them. Here the Empirical Mode Decomposition technique, which is designed to deal with non-stationary, nonlinear time series, becomes useful. It allows the identification of two characteristic time scales in the water level data that can be linked to solar variability: the 88 year period and a time scale of about 200 years. These time scales are also present in the concurrent aurora data. Auroras are driven by coronal mass ejections and the rate of auroras is an excellent proxy for solar variabiliy. Analysis of auroral data contemporaneous with the Nile data shows peaks at 88 years and about 200 years. This suggests a physical link between solar variability and the low-frequency variations of the Nile water level. The link involves the influence of solar variability on the North Annual Mode of atmospheric variability and its North Atlantic and Indian Oceans patterns that affect rainfall over Eastren Equatorial Africa where the Nile originates.

Occurrence of pesticides in fish tissues, water and soil sediment from Manzala Lake and River Nile.

PubMed

Osfor, M M; Abd el Wahab, A M; el Dessouki, S A

1998-02-01

Pesticides constitute the major source of potential environmental hazard to man and animal as they are present and concentrated in the food chain. This study was conducted on 136 samples of water, sediment and fish for detection and determination of pesticide residues in this ecosystem. Highly significant differences were found in levels of Indian, heptachlor, endrin, dieldrin, P,P'-DDE and propoxur in River Nile water when compared with that of Manzala Lake. Levels of Indian, endrin, malathion and diazinon were significantly higher in soil sediment of Manzala Lake, while the levels of heptachlor, aldrine, P,P'-DDE, DDT, parathion, propoxur and zectran were significantly higher in soil sediment of River Nile. Boury fish of Manzala Lake contained higher levels of heptachlor, aldrin, P,P'-DDE and malathion, while boury fish of River Nile contained a higher level of zectran only. This survey, thus indicated that Manzala Lake and even the River Nile which was used as control are heavily contaminated with chlorinated hydrocarbons (Indian, heptachlor, aldrin, endrin, dieldrin, P,P'-DDE and DDT), organic phosphorus compounds (malathion, dimethoat, diazinon and parathion) and carbamate pesticides (propoxur and zectran).

Mapping Mesophotic Reefs Along the Brazilian Continental Margin

NASA Astrophysics Data System (ADS)

Bastos, A.; Moura, R.; Amado Filho, G.; Ferreira, L.; Boni, G.; Vedoato, F.; D'Agostini, D.; Lavagnino, A. C.; Leite, M. D.; Quaresma, V.

2017-12-01

Submerged or drowned reefs constitute an important geological record of sea level variations, forming the substrate for the colonization of modern benthic mesophotic communities. Although mapping mesophotic reefs has increased in the last years, their spatial distribution is poorly known and the worldwide occurrence of this reef habitat maybe underestimated. The importance in recognizing the distribution of mesophotic reefs is that they can act as a refuge for corals during unsuitable environmental conditions and a repository for shallow water corals. Here we present the result of several acoustic surveys that mapped and discovered new mesophotic reefs along the Eastern and Equatorial Brazilian Continental Margin. Seabed mapping was carried out using multibeam and side scan sonars. Ground truthing was obtained using drop camera or scuba diving. Mesophotic reefs were mapped in water depths varying from 30 to 100m and under distinct oceanographic conditions, especially in terms of river load input and shelf width. Reefs showed distinct morphologies, from low relief banks and paleovalleys to shelf edge ridges. Extensive occurrence of low relief banks were mapped along the most important coralline complex province in the South Atlantic, the Abrolhos Shelf. These 30 to 40m deep banks, have no more than 3 meters in height and may represent fringing reefs formed during sea level stabilization. Paleovalleys mapped along the eastern margin showed the occurrence of coralgal ledges along the channel margins. Paleovalleys are usually deeper than 45m and are associated with outer shelf rhodolith beds. Shelf edge ridges (80 to 120m deep) were mapped along both margins and are related to red algal encrusting irregular surfaces that have more than 3m in height, forming a rigid substrate for coral growth. Along the Equatorial Margin, off the Amazon mouth, shelf edge patch reefs and rhodolith beds forming encrusting surfaces and shelf edge ridges were mapped in water depths greater than 100m. Thus, the occurrence of mesophotic reefs along the Brazilian Margin is influenced by transgressive morphological features, which could be used as a surrogate for mesophotic reef distribution. The extensive occurrence of rhodolith beds on the outer shelf characterizes most of these reefs.

The Zika Virus | NIH MedlinePlus the Magazine

MedlinePlus

... member of the flavivirus family. Other flaviviruses include dengue, yellow fever, and West Nile virus. Like its ... grantees have long studied Zika relatives, such as dengue and West Nile virus. Those studies provide a ...

Earth Observation

NASA Image and Video Library

2014-08-23

ISS040-E-105768 (23 Aug. 2014) --- One of the Expedition 40 crew members aboard the International Space Station, flying at an altitude of 221 nautical miles, captured this image of Egypt's Nile River and Lake Nasser on Aug. 23, 2014. The Aswan High Dam is to the right of center in the 70mm focal-length image, as the Nile flows southward (to the right in this image) toward Cairo and it?s Mediterranean delta (both out of frame at right). The Red Sea, which runs more or less parallel to the Nile, is out of frame at bottom.

Yellow fever vector live-virus vaccines: West Nile virus vaccine development.

PubMed

Arroyo, J; Miller, C A; Catalan, J; Monath, T P

2001-08-01

By combining molecular-biological techniques with our increased understanding of the effect of gene sequence modification on viral function, yellow fever 17D, a positive-strand RNA virus vaccine, has been manipulated to induce a protective immune response against viruses of the same family (e.g. Japanese encephalitis and dengue viruses). Triggered by the emergence of West Nile virus infections in the New World afflicting humans, horses and birds, the success of this recombinant technology has prompted the rapid development of a live-virus attenuated candidate vaccine against West Nile virus.

Evaluating the Use of Commercial West Nile Virus Antigens as Positive Controls in the Rapid Analyte Measurement Platform West Nile Virus Assay.

PubMed

Burkhalter, Kristen L; Savage, Harry M

2015-12-01

We evaluated the utility of 2 types of commercially available antigens as positive controls in the Rapid Analyte Measurement Platform (RAMP®) West Nile virus (WNV) assay. Purified recombinant WNV envelope antigens and whole killed virus antigens produced positive RAMP results and either type would be useful as a positive control. Killed virus antigens provide operational and economic advantages and we recommend their use over purified recombinant antigens. We also offer practical applications for RAMP positive controls and recommendations for preparing them.

Fatal human eosinophilic meningo-encephalitis caused by CNS co-infection with Halicephalobus gingivalis and West Nile virus.

PubMed

Anwar, M A; Gokozan, H N; Ball, M K; Otero, J; McGwire, B S

2015-10-01

The saprophytic nematode Halicephalobus is a rare cause of fatal human meningo-encephalitis, and West Nile virus is neurotropic flavivirus implicated in a variety of clinical neurologic syndromes. Here we report a case of rapidly progressive CNS encephalopathy and death. Serologic, immuno-histochemical, histopathologic and nucleic acid studies demonstrate the presence of active Halicephalobus and West Nile virus in the CNS tissue. This is the first reported case of co-infection with these neurotropic pathogens. Copyright © 2015. Published by Elsevier Ireland Ltd.

Detection of West Nile and Usutu Viruses in Italian Free Areas: Entomological Surveillance in Piemonte and Liguria Regions, 2014.

PubMed

Pautasso, Alessandra; Radaelli, Maria Cristina; Ballardini, Marco; Francese, Danila Raffaella; Verna, Federica; Modesto, Paola; Grattarola, Carla; Desiato, Rosanna; Bertolini, Silvia; Vitale, Nicoletta; Ferrari, Angelo; Rossini, Irene; Accorsi, Annalisa; Mosca, Andrea; Monaco, Federica; Savini, Giovanni; Prearo, Marino; Mignone, Walter; Chiavacci, Laura; Casalone, Cristina

2016-04-01

West Nile virus and Usutu virus have established in different parts of Italy over the past 10 years. Piemonte and Liguria Regions (Northwestern Italy) are known to be nonendemic areas, despite the presence of competent vectors and environmental conditions conducive to maintaining infection. This work evidences for the first time, through an entomological surveillance implemented on the basis of risk factor approach, the presence of West Nile and Usutu viruses in Piemonte and Liguria Regions (Northwestern Italy).

Deep Explosive Volcanism on the Gakkel Ridge and Seismological Constraints on Shallow Recharge at TAG Active Mound

DTIC Science & Technology

2013-02-01

Siberian margin (6.5 mm yr-1 full rate) [Vogt et al., 1979; DeMets et al., 1994; Sella et al., 2002]. For comparison, the ultraslow- spreading Southwest...that systemati~:ally decrea:;e from 12.8 mm yr 1 <~l its western eod {near Greeolund) to 6.5 nun yr 1 at its eastern end (the Siberian margin ) [Vogt et...perennial pack ice has made it possible to test these hypotheses. In 2007 the AGAVE expedi- tion utilized a oovcl vduclc (CAMPER) to acquire high

RAPD-SCAR Markers for Genetically Improved NEW GIFT Nile Tilapia (Oreochromis niloticus niloticus L.) and Their Application in Strain Identification.

PubMed

Li, Si-Fa; Tang, Shou-Jie; Cai, Wan-Qi

2010-04-01

The NEW GIFT Nile tilapia (Oreochromis niloticus niloticus L.) is a nationally certificated new strain selected over 14 years and 9 generations from the base strain of GIFT Nile tilapia, introduced in 1994. This new variety has been extended in most of areas of China. The management of genetically improved strains, including the genetic markers for identification is needed urgently. RAPD analysis was conducted and their conversion to SCAR markers was developed. From NEW GIFT Nile tilapia, two strain-specific RAPD bands, S(304 )(624 bp ) and S(36 )(568 bp ) were identified. The strain-specific RAPD bands were gel-purified, cloned, and sequenced. Locus-specific primers were then designed to amplify the strain-specific bands. PCR amplification was conducted to test the variations in allele frequencies of two converted SCAR markers among the NEW GIFT Nile tilapia and its base strains, as well as 7 additional farmed strains worldwide. The frequency of SCAR marker I (553 bp) was 85.7% in NEW GIFT Nile tilapia, but 16.7% in the base strain. The frequency of SCAR marker II (558 bp) was 91.4% in NEW GIFT Nile tilapia, but 0% - 70% in the 7 other strains. In order to confirm the utility of these two markers, an examination was conducted for a wild population from Egypt, resulted the frequency of SCAR I and II was 10% and 70%, respectively, much lower than that of New GIFT strain. The increase in allele frequency of these two SCAR markers suggests that these markers might be genetically linked to the quantitative trait loci (QTL) underlining the performance traits by long term selection, and indicate the bright potential of SCAR marker technology for tracking generations during selection progress and for distinguishing among genetically improved strain and other strains.

The monoamine oxidase inhibition properties of selected structural analogues of methylene blue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delport, Anzelle

The thionine dye, methylene blue (MB), is a potent inhibitor of monoamine oxidase (MAO) A, a property that may, at least in part, mediate its antidepressant effects in humans and animals. The central inhibition of MAO-A by MB has also been linked to serotonin toxicity (ST) which may arise when MB is used in combination with serotonergic drugs. Structural analogues and the principal metabolite of MB, azure B, have also been reported to inhibit the MAO enzymes, with all compounds exhibiting specificity for the MAO-A isoform. To expand on the structure-activity relationships (SARs) of MAO inhibition by MB analogues, themore » present study investigates the human MAO inhibition properties of five MB analogues: neutral red, Nile blue, new methylene blue, cresyl violet and 1,9-dimethyl methylene blue. Similar to MB, these analogues also are specific MAO-A inhibitors with cresyl violet (IC{sub 50} = 0.0037 μM), Nile blue (IC{sub 50} = 0.0077 μM) and 1,9-dimethyl methylene blue (IC{sub 50} = 0.018 μM) exhibiting higher potency inhibition compared to MB (IC{sub 50} = 0.07 μM). Nile blue also represents a potent MAO-B inhibitor with an IC{sub 50} value of 0.012 μM. From the results it may be concluded that non-thionine MB analogues (e.g. cresyl violet and Nile blue) also may exhibit potent MAO inhibition, a property which should be considered when using these compounds in pharmacological studies. Benzophenoxazines such as cresyl violet and Nile blue are, similar to phenothiazines (e.g. MB), representative of high potency MAO-A inhibitors with a potential risk of ST. - Highlights: • MB analogues, cresyl violet and Nile blue, are high potency MAO-A inhibitors. • Nile blue also represents a potent MAO-B inhibitor. • Potent MAO-A inhibition should alert to potential serotonin toxicity.« less

West Nile Virus: Review of the Literature

PubMed Central

Petersen, Lyle R.; Brault, Aaron C.; Nasci, Roger S.

2015-01-01

IMPORTANCE Since its introduction in North America in 1999,West Nile virus has produced the 3 largest arboviral neuroinvasive disease outbreaks ever recorded in the United States. OBJECTIVE To review the ecology, virology, epidemiology, clinical characteristics, diagnosis, prevention, and control of West Nile virus, with an emphasis on North America. EVIDENCE REVIEW PubMed electronic database was searched through February 5, 2013. United States national surveillance data were gathered from the Centers for Disease Control and Prevention. FINDINGS West Nile virus is now endemic throughout the contiguous United States, with 16 196 human neuroinvasive disease cases and 1549 deaths reported since 1999. More than 780 000 illnesses have likely occurred. To date, incidence is highest in the Midwest from mid-July to early September. West Nile fever develops in approximately 25% of those infected, varies greatly in clinical severity, and symptoms may be prolonged. Neuroinvasive disease (meningitis, encephalitis, acute flaccid paralysis) develops in less than 1% but carries a fatality rate of approximately 10%. Encephalitis has a highly variable clinical course but often is associated with considerable long-term morbidity. Approximately two-thirds of those with paralysis remain with significant weakness in affected limbs. Diagnosis usually rests on detection of IgM antibody in serum or cerebrospinal fluid. Treatment is supportive; no licensed human vaccine exists. Prevention uses an integrated pest management approach, which focuses on surveillance, elimination of mosquito breeding sites, and larval and adult mosquito management using pesticides to keep mosquito populations low. During outbreaks or impending outbreaks, emphasis shifts to aggressive adult mosquito control to reduce the abundance of infected, biting mosquitoes. Pesticide exposure and adverse human health events following adult mosquito control operations for West Nile virus appear negligible. CONCLUSIONS AND RELEVANCE In North America, West Nile virus has and will remain a formidable clinical and public health problem for years to come. PMID:23860989

76 FR 24535 - Notice of Determinations Regarding Eligibility To Apply for Worker Adjustment Assistance

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-02

... investigation resulting in-- (A) An affirmative determination of serious injury or threat thereof under section.... Container the Americas Division; Leased Workers from Manpower. 75,105 DW National Standard-Niles, Niles, MI...

Al Jazirah, Sudan

NASA Image and Video Library

2008-05-09

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. This image was acquired December 25, 2006 by NASA Terra spacecraft.

Earth observations during STS-58

NASA Image and Video Library

1998-07-28

STS058-92-064 (18 Oct-1 Nov 1993) --- This oblique view, looking northeast from central Egypt, shows great expanses of the sand covered and rocky Western Desert in the foreground (bottom). The dark patches bottom right are the Dakhla Oases on the south side of an escarpment. For centuries camel trains have moved from here to the Nile Valley, seen here as a broad green line winding through the desert. The northern half of Egypt's Nile appears here, from about the latitude of Luxor to the delta. Green colors indicate the small area of crops which feed Egypt's population of 55 million. The Nile Delta is partly obscured by a band of clouds, but can be discerned at the coast as a flattened triangle of green. The smaller triangle close by is the Faiyum Basin, a depression irrigated by water from the Nile. The coast of the Mediterranean Sea appears left.

Mixed non-covalent assemblies of ethynyl nile red and ethynyl pyrene along oligonucleotide templates.

PubMed

Ensslen, Philipp; Fritz, Yannic; Wagenknecht, Hans-Achim

2015-01-14

Ethynyl pyrene and ethynyl nile red as modifications at the 5-position of 2'-deoxyuridines self-assemble non-covalently and specifically along oligo-2'-deoxyadenosines as templates. Oligo-2'-deoxyadenosines of the lengths (dA)10-(dA)20 are able to retain nearly exactly as many ethynyl nile red units in solution as binding sites are available on these templates. In contrast, in the presence of oligo-2'-thymidines the ethynyl nile red moieties are similarly insoluble to those in the absence of any oligonucleotide and yield an aggregate. The mixed assemblies of both chromophores are highly ordered, show left-handed chirality and yield dual fluorescence. The strong excitonic coupling indicates assemblies with a high degree of order. These results show that DNA represents an important supramolecular scaffold for the templated, helical and non-covalent arrangement not only for one type of chromophore but also for mixtures of two different chromophores.

A Review of Vaccine Approaches for West Nile Virus

PubMed Central

Iyer, Arun V.; Kousoulas, Konstantin G.

2013-01-01

The West Nile virus (WNC) first appeared in North America in 1999. The North American lineages of WNV were characterized by the presence of neuroinvasive and neurovirulent strains causing disease and death in humans, birds and horses. The 2012 WNV season in the United States saw a massive spike in the number of neuroinvasive cases and deaths similar to what was seen in the 2002–2003 season, according to the West Nile virus disease cases and deaths reported to the CDC by year and clinical presentation, 1999–2012, by ArboNET (Arboviral Diseases Branch, Centers for Disease Control and Prevention). In addition, the establishment and recent spread of lineage II WNV virus strains into Western Europe and the presence of neurovirulent and neuroinvasive strains among them is a cause of major concern. This review discusses the advances in the development of vaccines and biologicals to combat human and veterinary West Nile disease. PMID:24025396

A review of vaccine approaches for West Nile virus.

PubMed

Iyer, Arun V; Kousoulas, Konstantin G

2013-09-10

The West Nile virus (WNC) first appeared in North America in 1999. The North American lineages of WNV were characterized by the presence of neuroinvasive and neurovirulent strains causing disease and death in humans, birds and horses. The 2012 WNV season in the United States saw a massive spike in the number of neuroinvasive cases and deaths similar to what was seen in the 2002-2003 season, according to the West Nile virus disease cases and deaths reported to the CDC by year and clinical presentation, 1999-2012, by ArboNET (Arboviral Diseases Branch, Centers for Disease Control and Prevention). In addition, the establishment and recent spread of lineage II WNV virus strains into Western Europe and the presence of neurovirulent and neuroinvasive strains among them is a cause of major concern. This review discusses the advances in the development of vaccines and biologicals to combat human and veterinary West Nile disease.

Climate-based models for West Nile Culex mosquito vectors in the Northeastern US

NASA Astrophysics Data System (ADS)

Gong, Hongfei; Degaetano, Arthur T.; Harrington, Laura C.

2011-05-01

Climate-based models simulating Culex mosquito population abundance in the Northeastern US were developed. Two West Nile vector species, Culex pipiens and Culex restuans, were included in model simulations. The model was optimized by a parameter-space search within biological bounds. Mosquito population dynamics were driven by major environmental factors including temperature, rainfall, evaporation rate and photoperiod. The results show a strong correlation between the timing of early population increases (as early warning of West Nile virus risk) and decreases in late summer. Simulated abundance was highly correlated with actual mosquito capture in New Jersey light traps and validated with field data. This climate-based model simulates the population dynamics of both the adult and immature mosquito life stage of Culex arbovirus vectors in the Northeastern US. It is expected to have direct and practical application for mosquito control and West Nile prevention programs.

[Birds, mosquitoes and West Nile virus: little risk of West Nile fever in the Netherlands].

PubMed

Duijster, Janneke W; Stroo, C J Arjan; Braks, Marieta A H

2016-01-01

Due to increased incidence of West Nile fever (WNF) in Europe and the rapid spread of West Nile virus (WNV) in the US, it is commonly thought that it will only be a matter of time before WNV reaches the Netherlands. However, assessing whether WNV is really a threat to the Dutch population is challenging, due to the numerous factors affecting transmission of the virus. Some of these factors are known to limit the risk of WNF in the Netherlands. This risk is determined by the interaction between the pathogen (WNV), the vectors (Culex mosquitoes), the reservoirs (birds) and the exposure of humans to infected mosquitoes. In this paper, we discuss the factors influencing introduction, establishment and spread of WNV in the Netherlands. The probability that each of these three phases will occur in the Netherlands is currently relatively small, as is the risk of WNF infection in humans in the Netherlands.

Milankovitch forcing and role of Indonesian Gateway on middle Miocene climate and carbon cycle: New perspective from the South China Sea, equatorial West Pacific and East Indian Ocean

NASA Astrophysics Data System (ADS)

Holbourn, A.; Kuhnt, W.; Schulz, M.

2003-04-01

The enigmatic long-term positive carbon isotope excursion ("Monterey excursion") in the middle Miocene exhibits an apparent 400 ky cyclicity (long eccentricity cycle of the Milankovitch frequency band). Similar isotope excursion are known from the mid-Cretaceous and may be a characteristic feature of a greenhouse world with extreme warm climate, high sealevel, and a dominantly zonal circulation pattern in the world ocean. This period of extreme warmth (the mid-Miocene climate optimum) ended between 14.2 and 13.8 Ma, when a significant increase in deep-water oxygen isotopic values occurred that was related to the growth of the East Antarctic ice sheet. Plate tectonic movements between Australia and SE Asia, ultimately leading to the closure of the deep water gateway connecting the Indian and Pacific Oceans, started prior to this paleoceanographic change. We used benthic deep water oxygen and carbon isotope curves in combination with new age models at critical locations along the northern margin of the Indonesian Gateway (South China Sea, ODP Site 1146), at the western end of the gateway (NW Australian margin, ODP Site 761) and at the eastern end of the gateway (Ontong Java Plateau, ODP Site 806) to investigate the frequency and amplitude of deep water isotope fluctuations during the middle Miocene. High resolution sediment color reflectance data, benthic carbon isotopes and foraminiferal assemblages are used as proxies of deep-water ventilation and carbon flux. Our results indicate Milankovitch forcing on virtually all proxies and a change from eccentricity to precession driven cyclicity at approximately 15 Ma. Our data reveal increased carbon flux and a restricted deep water exchange between the Pacific Ocean and Indian Ocean through the Indonesian Gateway during the middle Miocene climate optimum. After 13.6 Ma, the decrease in d13C was strongest at Site 806, indicating a marked change in the deep-water circulation of the equatorial West Pacific and a switch to a more distant deep-water source.

Evolution of Northeast Atlantic Magmatic Continental Margins from an Ethiopian-Afar Perspective

NASA Astrophysics Data System (ADS)

England, R. W.; Cornwell, D. G.; Ramsden, A. M.

2014-12-01

One of the major problems interpreting the evolution of magmatic continental margins is that the structure which should record the pre-magmatic evolution of the rift and which potentially influences the character of the rifting process is partially or completely obscured by thick basalt lava flows and sills. A limited number of deep reflection seismic profiles acquired with tuned seismic sources have penetrated the basalts and provide an image of the pre-magmatic structure, otherwise the principle data are lower resolution wide-angle/refraction profiles and potential field models which have greater uncertainties associated with them. In order to sidestep the imaging constraints we have examined the Ethiopian - Afar rift system to try to understand the rifting process. The Main Ethiopian rift contains an embryonic magmatic passive margin dominated by faulting at the margins of the rift and en-echelon magmatic zones at the centre. Further north toward Afar the rift becomes in-filled with extensive lava flows fed from fissure systems in the widening rift zone. This rift system provides, along its length, a series of 'snapshots' into the possible tectonic evolution of a magmatic continental margin. Deep seismic profiles crossing the NE Atlantic margins reveal ocean dipping reflector sequences (ODRS) overlying extended crust and lower crustal sill complexes of intruded igneous rock, which extend back beneath the continental margin. The ODRS frequently occur in fault bounded rift structures along the margins. We suggest, by analogy to the observations that can be made in the Ethiopia-Afar rift that these fault bounded basins largely form at the embryonic rift stage and are then partially or completely filled with lavas fed from fissures which are now observed as the ODRS. Also in the seismic profiles we identify volcanic constructs on the ODRS which we interpret as the equivalent of the present day fissure eruptions seen in Afar. The ocean ward dip on the ODRS is predominantly the result of post-eruption differential subsidence, as opposed to syn-eruption extension. The timing of intrusion of the lower crustal sill complexes remains unclear but they are most likely to have been emplaced as the supply of magma increased, which implies they are a late stage addition.

Two major Cenozoic episodes of phosphogenesis recorded in equatorial Pacific seamount deposits

USGS Publications Warehouse

Hein, J.R.; Hsueh-Wen, Yeh; Gunn, S.H.; Sliter, W.V.; Benninger, L.M.; Chung-Ho, Wang

1993-01-01

The phosphorites occur in a wide variety of forms, but most commonly carbonate fluorapatite (CFA) replaced middle Eocene and older carbonate sediment in a deep water environment (>1000 m). Element ratios distinguish seamount phosphorites from continental margin, plateau, and insular phosphorites. Uranium and thorium contents are low and total rare earch element (REE) contents are generally high. The paleoceanographic conditions initiated and sustained development of phosphorite by accumulation of dissolved phosphorus in the deep sea during relatively stable climatic conditions when oceanic circulation was sluggish. Fluctuations in climate, sealevel, and upwelling that accompanied the climate transitions may have driven cycles of enrichment and depletion of the deep-sea phosphorus reservoir. -from Authors

Identification and biochemical characterization of small-molecule inhibitors of west nile virus serine protease by a high-throughput screen.

PubMed

Mueller, Niklaus H; Pattabiraman, Nagarajan; Ansarah-Sobrinho, Camilo; Viswanathan, Prasanth; Pierson, Theodore C; Padmanabhan, R

2008-09-01

West Nile virus and dengue virus are mosquito-borne flaviviruses that cause a large number of human infections each year. No vaccines or chemotherapeutics are currently available. These viruses encode a serine protease that is essential for polyprotein processing, a required step in the viral replication cycle. In this study, a high-throughput screening assay for the West Nile virus protease was employed to screen approximately 32,000 small-molecule compounds for identification of inhibitors. Lead inhibitor compounds with three distinct core chemical structures (1 to 3) were identified. In a secondary screening of selected compounds, two compounds, belonging to the 8-hydroxyquinoline family (compounds A and B) and containing core structure 1, were identified as potent inhibitors of the West Nile virus protease, with K(i) values of 3.2 +/- 0.3 microM and 3.4 +/- 0.6 microM, respectively. These compounds inhibited the dengue virus type 2 protease with K(i) values of 28.6 +/- 5.1 microM and 30.2 +/- 8.6 microM, respectively, showing some selectivity in the inhibition of these viral proteases. However, the compounds show no inhibition of cellular serine proteases, trypsin, or factor Xa. Kinetic analysis and molecular docking of compound B onto the known crystal structure of the West Nile virus protease indicate that the inhibitor binds in the substrate-binding cleft. Furthermore, compound B was capable of inhibiting West Nile virus RNA replication in cultured Vero cells (50% effective concentration, 1.4 +/- 0.4 microM; selectivity index, 100), presumably by inhibition of polyprotein processing.

Fish faunal resurgence in Lake Nabugabo, East Africa

USGS Publications Warehouse

Chapman, L.J.; Chapman, Colin A.; Schofield, P.J.; Olowo, J.P.; Kaufman, L.S.; Seehausen, O.; Ogutu-Ohwayo., R.

2003-01-01

 In Lake Nabugabo, Uganda, a small satellite of the equatorial Lake Victoria, approximately 50% of the indigenous fish species disappeared from the open waters subsequent to establishment of the introduced predatory Nile perch (   Lates niloticus ). However, several of these species persisted in wetland refugia. Over the past decade, Nile perch in Lake Nabugabo have been intensively fished. Herein we report a resurgence of some indigenous species in open waters. In a multiyear study, we used annual transects in inshore and offshore waters of exposed ( no wetland ) and wetland habitats to document the pattern of resurgence. In 1995, haplochromine cichlids were largely confined to inshore areas, particularly wetland ecotones, and were rare in Nile perch stomachs, as were most other indigenous species. By 2000 haplochromine cichlids were abundant in inshore and offshore areas of both exposed and wetland transects. Several indigenous noncichlids also reappeared in the main lake, including three of the four original mormyrid species. Between 1995 and 1999, there was a dramatic increase in the proportion of haplochromines in the diet of Nile perch. When haplochromines were rare ( 1995 ), Nile perch switched from an invertebrate-dominated diet to piscivory at a large size ( 30 cm total length ). In 2000, however, Nile perch were strongly piscivorous by 5–10 cm total length. The pattern of faunal loss and recovery in Lake Nabugabo demonstrates the importance of refugia in providing the seeds of resurgence and provides a model with which to understand some changes in Lake Victoria.

Structural and Sequence Stratigraphic Analysis of the Onshore Nile Delta, Egypt.

NASA Astrophysics Data System (ADS)

Barakat, Moataz; Dominik, Wilhelm

2010-05-01

The Nile Delta is considered the earliest known delta in the world. It was already described by Herodotus in the 5th Century AC. Nowadays; the Nile Delta is an emerging giant gas province in the Middle East with proven gas reserves which have more than doubled in size in the last years. The Nile Delta basin contains a thick sedimentary sequence inferred to extend from Jurassic to recent time. Structural styles and depositional environments varied during this period. Facies architecture and sequence stratigraphy of the Nile Delta are resolved using seismic stratigraphy based on (2D seismic lines) including synthetic seismograms and tying in well log data. Synthetic seismograms were constructed using sonic and density logs. The combination of structural interpretation and sequence stratigraphy of the development of the basin was resolved. Seven chrono-stratigraphic boundaries have been identified and correlated on seismic and well log data. Several unconformity boundaries also identified on seismic lines range from angular to disconformity type. Furthermore, time structure maps, velocity maps, depth structure maps as well as Isopach maps were constructed using seismic lines and log data. Several structural features were identified: normal faults, growth faults, listric faults, secondary antithetic faults and large rotated fault blocks of manly Miocene age. In some cases minor rollover structures could be identified. Sedimentary features such as paleo-channels were distinctively recognized. Typical Sequence stratigraphic features such as incised valley, clinoforms, topsets, offlaps and onlaps are identified and traced on the seismic lines allowing a good insight into sequence stratigraphic history of the Nile Delta most especially in the Miocene to Pliocene clastic sedimentary succession.

Structure and evolution of the NE Atlantic conjugate margins off Norway and Greenland (Invited)

NASA Astrophysics Data System (ADS)

Faleide, J.; Planke, S.; Theissen-Krah, S.; Abdelmalak, M.; Zastrozhnov, D.; Tsikalas, F.; Breivik, A. J.; Torsvik, T. H.; Gaina, C.; Schmid, D. W.; Myklebust, R.; Mjelde, R.

2013-12-01

The continental margins off Norway and NE Greenland evolved in response to the Cenozoic opening of the NE Atlantic. The margins exhibit a distinct along-margin segmentation reflecting structural inheritance extending back to a complex pre-breakup geological history. The sedimentary basins at the conjugate margins developed as a result of multiple phases of post-Caledonian rifting from Late Paleozoic time to final NE Atlantic breakup at the Paleocene-Eocene transition. The >200 million years of repeated extension caused comprehensive crustal thinning and formation of deep sedimentary basins. The main rift phases span the following time intervals: Late Permian, late Middle Jurassic-earliest Cretaceous, Early-mid Cretaceous and Late Cretaceous-Paleocene. The late Mesozoic-early Cenozoic rifting was related to the northward propagation of North Atlantic sea floor spreading, but also linked to important tectonic events in the Arctic. The pre-drift extension is quantified based on observed geometries of crustal thinning and stretching factors derived from tectonic modeling. The total (cumulative) pre-drift extension amounts to in the order of 300 km which correlates well with estimates from plate reconstructions based on paleomagnetic data. Final lithospheric breakup at the Paleocene-Eocene transition culminated in a 3-6 m.y. period of massive magmatic activity during breakup and onset of early sea-floor spreading, forming a part of the North Atlantic Volcanic Province. At the outer parts of the conjugate margins, the lavas form characteristic seaward dipping reflector sequences and lava deltas that drilling has demonstrated to be subaerially and/or neritically erupted basalts. The continent-ocean transition is usually well defined as a rapid increase of P-wave velocities at mid- to lower-crustal levels. Maximum igneous crustal thickness of about 18 km is found across the outer Vøring Plateau on the Norwegian Margin, and lower-crustal P-wave velocities of up to 7.3 km/s are found at the bottom of the igneous crust here. The igneous crust, including the characteristic 7+ km/s lower crustal body, is even thicker on the East Greenland Margin. During the main igneous episode, sills intruded into the thick Cretaceous successions throughout the NE Atlantic margins. Strong crustal reflections can be mapped widespread on both conjugate margins. In some areas they are associated with the top of the high-velocity lower crustal body, in other areas they may represent deeply buried sedimentary sequence boundaries or moho at the base of the crust. Following breakup, the subsiding margins experienced modest sedimentation until the late Pliocene when large wedges of glacial sediments prograded into the deep ocean from uplifted areas along the continental margins. The outbuilding was probably initiated in Miocene time indicating pre-glacial tectonic uplift of Greenland, Fennoscandia and the Barents Shelf. The NE Atlantic margins also reveal evidence of widespread Cenozoic compressional deformation.

Dynamics of Organic Carbon Flux on the Northwest Atlantic Margin: Results from a Three-year Time-Series Sediment Trap Study

NASA Astrophysics Data System (ADS)

Hwang, J.; Manganini, S. J.; Montlucon, D. B.; Eglinton, T. I.

2012-12-01

Sinking particles have been collected on the Northwest Atlantic margin since summer 2004 to understand the dynamics of particle export and the role of the Deep Western Boundary Current in resuspension of particles from sediment and their horizontal transport. Three traps were deployed at roughly 1000m, 2000m, and 3000m (50 m above the bottom) on a mooring at 3000m isobath. The results from the 2004-2005 deployment have been published previously (Hwang et al., 2009). We report the results from summer 2004 to summer 2007 in this presentation. Lithogenic component accounted for an increasing fraction with increasing depth from 27% at 1000m to 42% at 3000m. Radiocarbon contents as Δ14C values of sinking particulate organic matter were significantly depleted from the value of particulate organic matter in the surface water. The 3-year average value decreased with increasing depth from +13 per mil at 1000m to -20 per mil at 3000m. As previously observed for the first year samples, radiocarbon content showed a strong negative correlation with aluminum concentration. Because there is no considerable riverine input the high concentrations of lithogenic component and depleted Δ14C values imply the influence of laterally transported particles resuspended from sediment. Fluxes of biogenic and lithogenic components and their temporal variation will be discussed in relation with production in the surface water, lateral supply of resuspended sediment, and the variability of the Deep Western Boundary Current. Hwang, J., et al. (2009), Dynamics of particle export on the Northwest Atlantic margin, Deep-Sea Res. I, 56, 1792-1803.

Gas hydrates (clathrates) causing pore-water freshening and oxygen isotope fractionation in deep-water sedimentary sections of terrigenous continental margins

USGS Publications Warehouse

Hesse, R.; Harrison, W.E.

1981-01-01

The occurrence of gas hydrates in deep-water sections of the continental margins predicted from anomalous acoustic reflectors on seismic profiles has been confirmed by recent deep-sea drilling results. On the Pacific continental slope off Guatemala gas hydrates were brought up for the first time from two holes (497, 498A) drilled during Leg 67 of the DSDP in water depths of 2360 and 5500 m, respectively. The hydrates occur in organic matter-rich Pleistocene to Miocene terrigenous sediments. In the hydrate-bearing zone a marked decrease in interstitial water chlorinities was observed starting at about 10-20 m subbottom depth. Pore waters at the bottom of the holes (near 400 m subbottom) have as little as half the chlorinity of seawater (i.e. 9???). Similar, but less pronounced, trends were observed during previous legs of the DSDP in other hydrate-prone segments of the continental margins where recharge of fresh water from the continent can be excluded (e.g. Leg 11). The crystallization of hydrates, like ice, excludes salt ions from the crystal structure. During burial the dissolved salts are separated from the solids. Subsidence results in a downward motion of the solids (including hydrates) relative to the pore fluids. Thawing of hydrates during recovery releases fresh water which is remixed with the pore fluid not involved in hydrate formation. The volume of the latter decreases downhole thus causing downward decreasing salinity (chlorinity). Hydrate formation is responsible for oxygen isotope fractionation with 18O-enrichment in the hydrate explaining increasingly more positive ??18O values in the pore fluids recovered (after hydrate dissociation) with depth. ?? 1981.

Contourite drifts on early passive margins as an indicator of established lithospheric breakup

NASA Astrophysics Data System (ADS)

Soares, Duarte M.; Alves, Tiago M.; Terrinha, Pedro

2014-09-01

The Albian-Cenomanian breakup sequence (BS) offshore Northwest Iberia is mapped, described and characterised for the first time in terms of its seismic and depositional facies. The interpreted dataset comprises a large grid of regional (2D) seismic-reflection profiles, complemented by Industry and ODP/DSDP borehole data. Within the BS are observed distinct seismic facies that reflect the presence of: (a) black shales and fine-grained turbidites, (b) mass-transport deposits (MTDs) and coarse-grained turbidites, and (c) contourite drifts. Borehole data show that these depositional systems developed as mixed carbonate-siliciclastic sediments proximally, and as organic-carbon-rich mudstones (black shales) distally on the Northwest Iberia margin. MTDs and turbidites tend to occur on the continental slope, frequently in association with large-scale olistostromes. Distally, these change into interbedded fine-grained turbidites and black shales showing widespread evidence of deep-water current activity towards the top of the BS. Current activity is expressed by intra-BS erosional surfaces and sediment drifts. The results in this paper are important as they demonstrate that contourite drifts are ubiquitous features in the study area after Aptian-Albian lithospheric breakup. Therefore, we interpret the recognition of contourite drifts in Northwest Iberia as having significant palaeogeographic implications. Contourite drifts materialise the onset of important deep-water circulation marking the establishment of oceanic gateways between two fully separated continental margins. As a corollary, we postulate the generation of deep-water geostrophic currents to have had significant impact on North Atlantic climate and ocean circulation during the Albian-Cenomanian, with the record of such impacts being preserved in the contourite drifts analysed in this work.

Recent Multidisciplinary Research Initiatives and IODP Drilling in the South China Sea

NASA Astrophysics Data System (ADS)

Lin, J.; Li, C. F.; Wang, P.; Kulhanek, D. K.

2016-12-01

The South China Sea (SCS) is the largest low-latitude marginal sea in the world. Its formation and evolution are linked to the complex continental-oceanic tectonic interaction of the Eurasian, Pacific, and Indo-Australian plates. Despite its relatively small size and short history, the SCS has undergone nearly a complete Wilson cycle from continental break-up to seafloor spreading to subduction, serving as a natural laboratory for studying the linkages between tectonic, volcanic, and oceanic processes. The last several years have witnessed significant progress in investigation of the SCS through comprehensive research programs using multidisciplinary approaches and enhanced international collaboration. The International Ocean Discovery Program (IODP) Expedition 349 drilled and cored five sites in the SCS in 2014. The expedition successfully obtained the first basaltic rock samples of the SCS relict spreading center, discovered large and frequent deep-sea turbidity events, and sampled multiple seamount volcaniclastic layers. In addition, high-resolution near-seafloor magnetic surveys were conducted in the SCS with survey lines passing near some of the IODP drilling sites. Together the IODP drilling and deep-tow magnetic survey results confirmed, for the first time, that the entire SCS basin might have stopped seafloor spreading at similar ages in early Miocene, providing important constraints on marginal sea geodynamic models. In 2007, IODP Expeditions 367 and 368 will drill the northern margin of the SCS to investigate the mechanisms of rifting to spreading processes. Meanwhile, major progress in studying the SCS processes has also been made through comprehensive multidisciplinary programs, for example, the eight-year-long "South China Sea Deep" initiative, which also supports and encourages strong international collaboration. This presentation will highlight the recent multidisciplinary research initiatives in investigation of the SCS and the important role of international collaboration.

15. VIEW OF THE ORIGINAL 10TON OVERHEAD NILES TRAVELING CRANE. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. VIEW OF THE ORIGINAL 10-TON OVERHEAD NILES TRAVELING CRANE. - Washington Water Power Company Post Falls Power Plant, Middle Channel Powerhouse & Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

Nile Delta

Atmospheric Science Data Center

2013-04-15

... west are the Great Pyramids of Giza. North of here the Nile branches into two distributaries, the Rosetta to the west and the Damietta to ... NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, D.C. The Terra spacecraft is managed ...

Prediction of future climate change for the Blue Nile, using a nested Regional Climate Model

NASA Astrophysics Data System (ADS)

Soliman, E.; Jeuland, M.

2009-04-01

Although the Nile River Basin is rich in natural resources, it faces many challenges. Rainfall is highly variable across the region, on both seasonal and inter-annual scales. This variability makes the region vulnerable to droughts and floods. Many development projects involving Nile waters are currently underway, or being studied. These projects will lead to land-use patterns changes and water distribution and availability. It is thus important to assess the effects of a) these projects and b) evolving water resource management and policies, on regional hydrological processes. This paper seeks to establish a basis for evaluation of such impacts within the Blue Nile River sub-basin, using the RegCM3 Regional Climate Model to simulate interactions between the land surface and climatic processes. We first present results from application of this RCM model nested with downscaled outputs obtained from the ECHAM5/MPI-OM1 transient simulations for the 20th Century. We then investigate changes associated with mid-21st century emissions forcing of the SRES A1B scenario. The results obtained from the climate model are then fed as inputs to the Nile Forecast System (NFS), a hydrologic distributed rainfall runoff model of the Nile Basin, The interaction between climatic and hydrological processes on the land surface has been fully coupled. Rainfall patterns and evaporation rates have been generated using RegCM3, and the resulting runoff and Blue Nile streamflow patterns have been simulated using the NFS. This paper compares the results obtained from the RegCM3 climate model with observational datasets for precipitation and temperature from the Climate Research Unit (UK) and the NASA Goddard Space Flight Center GPCP (USA) for 1985-2000. The validity of the streamflow predictions from the NFS is assessed using historical gauge records. Finally, we present results from modeling of the A1B emissions scenario of the IPCC for the years 2034-2055. Our results indicate that future changes in rainfall may vary over different areas of the Upper Blue Nile catchment in Ethiopia. Our results suggest that there may be good reasons for developing climate models with finer spatial resolution than the more commonly used GCMs.

Atribacteria from the Subseafloor Sedimentary Biosphere Disperse to the Hydrosphere through Submarine Mud Volcanoes.

PubMed

Hoshino, Tatsuhiko; Toki, Tomohiro; Ijiri, Akira; Morono, Yuki; Machiyama, Hideaki; Ashi, Juichiro; Okamura, Kei; Inagaki, Fumio

2017-01-01

Submarine mud volcanoes (SMVs) are formed by muddy sediments and breccias extruded to the seafloor from a source in the deep subseafloor and are characterized by the discharge of methane and other hydrocarbon gasses and deep-sourced fluids into the overlying seawater. Although SMVs act as a natural pipeline connecting the Earth's surface and subsurface biospheres, the dispersal of deep-biosphere microorganisms and their ecological roles remain largely unknown. In this study, we investigated the microbial communities in sediment and overlying seawater at two SMVs located on the Ryukyu Trench off Tanegashima Island, southern Japan. The microbial communities in mud volcano sediments were generally distinct from those in the overlying seawaters and in the well-stratified Pacific margin sediments collected at the Peru Margin, the Juan de Fuca Ridge flank off Oregon, and offshore of Shimokita Peninsula, northeastern Japan. Nevertheless, in-depth analysis of different taxonomic groups at the sub-species level revealed that the taxon affiliated with Atribacteria , heterotrophic anaerobic bacteria that typically occur in organic-rich anoxic subseafloor sediments, were commonly found not only in SMV sediments but also in the overlying seawater. We designed a new oligonucleotide probe for detecting Atribacteria using the catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). CARD-FISH, digital PCR and sequencing analysis of 16S rRNA genes consistently showed that Atribacteria are abundant in the methane plumes of the two SMVs (0.58 and 1.5 × 10 4 cells/mL, respectively) but not in surrounding waters, suggesting that microbial cells in subseafloor sediments are dispersed as "deep-biosphere seeds" into the ocean. These findings may have important implications for the microbial transmigration between the deep subseafloor biosphere and the hydrosphere.

Atribacteria from the Subseafloor Sedimentary Biosphere Disperse to the Hydrosphere through Submarine Mud Volcanoes

PubMed Central

Hoshino, Tatsuhiko; Toki, Tomohiro; Ijiri, Akira; Morono, Yuki; Machiyama, Hideaki; Ashi, Juichiro; Okamura, Kei; Inagaki, Fumio

2017-01-01

Submarine mud volcanoes (SMVs) are formed by muddy sediments and breccias extruded to the seafloor from a source in the deep subseafloor and are characterized by the discharge of methane and other hydrocarbon gasses and deep-sourced fluids into the overlying seawater. Although SMVs act as a natural pipeline connecting the Earth’s surface and subsurface biospheres, the dispersal of deep-biosphere microorganisms and their ecological roles remain largely unknown. In this study, we investigated the microbial communities in sediment and overlying seawater at two SMVs located on the Ryukyu Trench off Tanegashima Island, southern Japan. The microbial communities in mud volcano sediments were generally distinct from those in the overlying seawaters and in the well-stratified Pacific margin sediments collected at the Peru Margin, the Juan de Fuca Ridge flank off Oregon, and offshore of Shimokita Peninsula, northeastern Japan. Nevertheless, in-depth analysis of different taxonomic groups at the sub-species level revealed that the taxon affiliated with Atribacteria, heterotrophic anaerobic bacteria that typically occur in organic-rich anoxic subseafloor sediments, were commonly found not only in SMV sediments but also in the overlying seawater. We designed a new oligonucleotide probe for detecting Atribacteria using the catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). CARD-FISH, digital PCR and sequencing analysis of 16S rRNA genes consistently showed that Atribacteria are abundant in the methane plumes of the two SMVs (0.58 and 1.5 × 104 cells/mL, respectively) but not in surrounding waters, suggesting that microbial cells in subseafloor sediments are dispersed as “deep-biosphere seeds” into the ocean. These findings may have important implications for the microbial transmigration between the deep subseafloor biosphere and the hydrosphere. PMID:28676800

Development of a forward genetic screen to isolate oil mutants in the green microalga Chlamydomonas reinhardtii.

PubMed

Cagnon, Caroline; Mirabella, Boris; Nguyen, Hoa Mai; Beyly-Adriano, Audrey; Bouvet, Séverine; Cuiné, Stéphan; Beisson, Fred; Peltier, Gilles; Li-Beisson, Yonghua

2013-12-02

Oils produced by microalgae are precursors to biodiesel. To achieve a profitable production of biodiesel from microalgae, identification of factors governing oil synthesis and turnover is desirable. The green microalga Chlamydomonas reinhardtii is amenable to genetic analyses and has recently emerged as a model to study oil metabolism. However, a detailed method to isolate various types of oil mutants that is adapted to Chlamydomonas has not been reported. We describe here a forward genetic approach to isolate mutants altered in oil synthesis and turnover from C. reinhardtii. It consists of a three-step screening procedure: a primary screen by flow cytometry of Nile red stained transformants grown in 96-deep-well plates under three sequential conditions (presence of nitrogen, then absence of nitrogen, followed by oil remobilization); a confirmation step using Nile red stained biological triplicates; and a validation step consisting of the quantification by thin layer chromatography of oil content of selected strains. Thirty-one mutants were isolated by screening 1,800 transformants generated by random insertional mutagenesis (1.7%). Five showed increased oil accumulation under the nitrogen-replete condition and 13 had altered oil content under nitrogen-depletion. All mutants were affected in oil remobilization. This study demonstrates that various types of oil mutants can be isolated in Chlamydomonas based on the method set-up here, including mutants accumulating oil under optimal biomass growth. The strategy conceived and the protocol set-up should be applicable to other microalgal species such as Nannochloropsis and Chlorella, thus serving as a useful tool in Chlamydomonas oil research and algal biotechnology.

Neogene palaeochannel deposits in Sudan - Remnants of a trans-Saharan river system?

NASA Astrophysics Data System (ADS)

Bussert, Robert; Eisawi, Ali A. M.; Hamed, Basher; Babikir, Ibrahim A. A.

2018-05-01

The start of Nile-type trans-Saharan drainage systems in NE Africa during the Cenozoic is disputed. Stratigraphical and sedimentological data in Egypt are partly in conflict with the uplift history of potential source areas of water and sediment in East Africa. Here, we investigate outcrops of the Wadi Awatib Conglomerate in Sudan that provide the first evidence of northerly flowing Neogene rivers in the region. Dimension and relief of basal erosion surfaces, overall geometry of deposits and palaeocurrent indicators demonstrate that the deposits represent the fill of northward-oriented incised valleys. The conglomerates were deposited in deep gravel-bed rivers, by hyperconcentrated flows, tractions carpets and gravel bars, primarily during heavily sediment-laden floods of probably monsoonal origin. Stratigraphical and geomorphological relationships show that the deposits are between Eocene and Pliocene in age. Considering the structural history of the region and periods in the Cenozoic with palaeoclimatic conditions suitable for the production and transport of gravels, we hypothesize that the dramatic base-level fall during the Late Miocene Messinian salinity crisis in combination with a favorable palaeoclimate caused the incision of valleys and their subsequent filling with conglomerates. Sea-level change in the Mediterranean Sea and headward erosion of streams that were connected to the Egyptian Nile might have been the primary cause of valley incision and deposition of conglomerates, despite a location far inland from the coastline. We suggest that the deposits document a relatively young Neogene (Messinian to early Pliocene) trans-Saharan river system unrelated to uplift of the Ethiopian Plateau.

Influence of submarine morphology on bottom water flow across the western Ross Sea continental margin

USGS Publications Warehouse

Davey, F.J.; Jacobs, S.S.

2007-01-01

Multibeam sonar bathymetry documents a lack of significant channels crossing outer continental shelf and slope of the western Ross Sea. This indicates that movement of bottom water across the shelf break into the deep ocean in this area is mainly by laminar or sheet flow. Subtle, ~20 m deep and up to 1000 m wide channels extend down the continental slope, into tributary drainage patterns on the upper rise, and then major erosional submarine canyons. These down-slope channels may have been formed by episodic pulses of rapid down slope water flow, some recorded on bottom current meters, or by sub-ice melt water erosion from an icesheet grounded at the margin. Narrow, mostly linear furrows on the continental shelf thought to be caused by iceberg scouring are randomly oriented, have widths generally less than 400 m and depths less than 30m, and extend to water depths in excess of 600 m.

Subsurface metabolic potential on the Costa Rican Margin

NASA Astrophysics Data System (ADS)

Biddle, J.; Leon, Z. R.; Martino, A. J.; Bousses, K.; House, C. H.

2017-12-01

The distribution of archaea and bacteria and their associated metabolic abilities in the deep subseafloor are poorly understood. In order to explore this, we focused on samples from the Costa Rica margin IODP Expedition 334. The microbial community was analyzed via metagenomics in two different sites at multiple depths. At Site 1378, samples are from 2 meters below the sea floor (mbsf), 33 mbsf and 93 mbsf, and at Site 1379 from 22 mbsf to 45 mbsf. Whole community analysis of conserved gene markers in the metagenome show that the microbial community varies with depth, and drastically differs between the two geographically close sites. Thirty-two genomes were recovered from the metagenomic data with more than 30% completion. Archaea make 49% of all genomes recovered and over 90% of these recovered genomes belong to recently discovered and poorly characterized groups of Archaea. This study explored the relative dynamics of microbial communities in the deep biosphere and presents the metabolic potential of distinct subsurface biosphere archaeal groups.

Talonavicular joint arthroscopic portals: A cadaveric study of feasibility and safety.

PubMed

Xavier, Gabriel; Oliva, Xavier Martin; Rotinen, Mauri; Monzo, Mariano

2016-09-01

The objectives of the study were to evaluate the safety of hypothetical arthroscopic portals from talonavicular joint and to evaluate their reproducibility and enforceability. 19 cadaveric feet were marked and four arthroscopic portals were made (medial, dorsomedial, dorsolateral and lateral). The specimens were dissected in layers and the distances between neurovascular structures and the trocars were measured. Medial and dorsomedial portals were in average 8.3 and 8.7, respectively, to the saphenous vein and nerve. Dorsolateral portal was in average 8.1mm to the deep peroneal nerve and dorsalis pedis artery, and 9.1mm to the medial dorsal cutaneous branch of the superficial peroneal nerve. Lateral portal was in average 12.3mm to the intermediate dorsal cutaneous branch of the superficial peroneal nerve. Tested portals shown to have a good safety margin for the foot neurovascular deep dorsal structures and an acceptable safety margin for the superficial neurovascular structures. Copyright © 2015 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Extraterrestrial demise of banded iron formations 1.85 billion years ago

USGS Publications Warehouse

Slack, J.F.; Cannon, W.F.

2009-01-01

In the Lake Superior region of North America, deposition of most banded iron formations (BIFs) ended abruptly 1.85 Ga ago, coincident with the oceanic impact of the giant Sudbury extraterrestrial bolide. We propose a new model in which this impact produced global mixing of shallow oxic and deep anoxic waters of the Paleoproterozoic ocean, creating a suboxic redox state for deep seawater. This suboxic state, characterized by only small concentrations of dissolved O2 (???1 ??M), prevented transport of hydrothermally derived Fe(II) from the deep ocean to continental-margin settings, ending an ???1.1 billion-year-long period of episodic BIF mineralization. The model is supported by the nature of Precambrian deep-water exhalative chemical sediments, which changed from predominantly sulfide facies prior to ca. 1.85 Ga to mainly oxide facies thereafter. ?? 2009 Geological Society of America.

Volcanic passive margins: another way to break up continents

PubMed Central

Geoffroy, L.; Burov, E. B.; Werner, P.

2015-01-01

Two major types of passive margins are recognized, i.e. volcanic and non-volcanic, without proposing distinctive mechanisms for their formation. Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic, and represent distinctive features of Larges Igneous Provinces, in which regional fissural volcanism predates localized syn-magmatic break-up of the lithosphere. In contrast with non-volcanic margins, continentward-dipping detachment faults accommodate crustal necking at both conjugate volcanic margins. These faults root on a two-layer deformed ductile crust that appears to be partly of igneous nature. This lower crust is exhumed up to the bottom of the syn-extension extrusives at the outer parts of the margin. Our numerical modelling suggests that strengthening of deep continental crust during early magmatic stages provokes a divergent flow of the ductile lithosphere away from a central continental block, which becomes thinner with time due to the flow-induced mechanical erosion acting at its base. Crustal-scale faults dipping continentward are rooted over this flowing material, thus isolating micro-continents within the future oceanic domain. Pure-shear type deformation affects the bulk lithosphere at VPMs until continental breakup, and the geometry of the margin is closely related to the dynamics of an active and melting mantle. PMID:26442807

Volcanic passive margins: another way to break up continents.

PubMed

Geoffroy, L; Burov, E B; Werner, P

2015-10-07

Two major types of passive margins are recognized, i.e. volcanic and non-volcanic, without proposing distinctive mechanisms for their formation. Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic, and represent distinctive features of Larges Igneous Provinces, in which regional fissural volcanism predates localized syn-magmatic break-up of the lithosphere. In contrast with non-volcanic margins, continentward-dipping detachment faults accommodate crustal necking at both conjugate volcanic margins. These faults root on a two-layer deformed ductile crust that appears to be partly of igneous nature. This lower crust is exhumed up to the bottom of the syn-extension extrusives at the outer parts of the margin. Our numerical modelling suggests that strengthening of deep continental crust during early magmatic stages provokes a divergent flow of the ductile lithosphere away from a central continental block, which becomes thinner with time due to the flow-induced mechanical erosion acting at its base. Crustal-scale faults dipping continentward are rooted over this flowing material, thus isolating micro-continents within the future oceanic domain. Pure-shear type deformation affects the bulk lithosphere at VPMs until continental breakup, and the geometry of the margin is closely related to the dynamics of an active and melting mantle.

Drought and immunity determine the intensity of West Nile virus epidemics and climate change impacts

DOE PAGES

Paull, Sara H.; Horton, Daniel E.; Ashfaq, Moetasim; ...

2017-02-08

The effect of global climate change on infectious disease remains hotly debated because multiple extrinsic and intrinsic drivers interact to influence transmission dynamics in nonlinear ways. The dominant drivers of widespread pathogens, like West Nile virus, can be challenging to identify due to regional variability in vector and host ecology, with past studies producing disparate findings. Here, we used analyses at national and state scales to examine a suite of climatic and intrinsic drivers of continental-scale West Nile virus epidemics, including an empirically derived mechanistic relationship between temperature and transmission potential that accounts for spatial variability in vectors. We foundmore » that drought was the primary climatic driver of increased West Nile virus epidemics, rather than within-season or winter temperatures, or precipitation independently. Local-scale data from one region suggested drought increased epidemics via changes in mosquito infection prevalence rather than mosquito abundance. In addition, human acquired immunity following regional epidemics limited subsequent transmission in many states. We show that over the next 30 years, increased drought severity from climate change could triple West Nile virus cases, but only in regions with low human immunity. Lastly, these results illustrate how changes in drought severity can alter the transmission dynamics of vector-borne diseases.« less

Drought and immunity determine the intensity of West Nile virus epidemics and climate change impacts

PubMed Central

Horton, Daniel E.; Ashfaq, Moetasim; Rastogi, Deeksha; Kramer, Laura D.; Diffenbaugh, Noah S.

2017-01-01

The effect of global climate change on infectious disease remains hotly debated because multiple extrinsic and intrinsic drivers interact to influence transmission dynamics in nonlinear ways. The dominant drivers of widespread pathogens, like West Nile virus, can be challenging to identify due to regional variability in vector and host ecology, with past studies producing disparate findings. Here, we used analyses at national and state scales to examine a suite of climatic and intrinsic drivers of continental-scale West Nile virus epidemics, including an empirically derived mechanistic relationship between temperature and transmission potential that accounts for spatial variability in vectors. We found that drought was the primary climatic driver of increased West Nile virus epidemics, rather than within-season or winter temperatures, or precipitation independently. Local-scale data from one region suggested drought increased epidemics via changes in mosquito infection prevalence rather than mosquito abundance. In addition, human acquired immunity following regional epidemics limited subsequent transmission in many states. We show that over the next 30 years, increased drought severity from climate change could triple West Nile virus cases, but only in regions with low human immunity. These results illustrate how changes in drought severity can alter the transmission dynamics of vector-borne diseases. PMID:28179512

Drought and immunity determine the intensity of West Nile virus epidemics and climate change impacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paull, Sara H.; Horton, Daniel E.; Ashfaq, Moetasim

The effect of global climate change on infectious disease remains hotly debated because multiple extrinsic and intrinsic drivers interact to influence transmission dynamics in nonlinear ways. The dominant drivers of widespread pathogens, like West Nile virus, can be challenging to identify due to regional variability in vector and host ecology, with past studies producing disparate findings. Here, we used analyses at national and state scales to examine a suite of climatic and intrinsic drivers of continental-scale West Nile virus epidemics, including an empirically derived mechanistic relationship between temperature and transmission potential that accounts for spatial variability in vectors. We foundmore » that drought was the primary climatic driver of increased West Nile virus epidemics, rather than within-season or winter temperatures, or precipitation independently. Local-scale data from one region suggested drought increased epidemics via changes in mosquito infection prevalence rather than mosquito abundance. In addition, human acquired immunity following regional epidemics limited subsequent transmission in many states. We show that over the next 30 years, increased drought severity from climate change could triple West Nile virus cases, but only in regions with low human immunity. Lastly, these results illustrate how changes in drought severity can alter the transmission dynamics of vector-borne diseases.« less

Drought and immunity determine the intensity of West Nile virus epidemics and climate change impacts.

PubMed

Paull, Sara H; Horton, Daniel E; Ashfaq, Moetasim; Rastogi, Deeksha; Kramer, Laura D; Diffenbaugh, Noah S; Kilpatrick, A Marm

2017-02-08

The effect of global climate change on infectious disease remains hotly debated because multiple extrinsic and intrinsic drivers interact to influence transmission dynamics in nonlinear ways. The dominant drivers of widespread pathogens, like West Nile virus, can be challenging to identify due to regional variability in vector and host ecology, with past studies producing disparate findings. Here, we used analyses at national and state scales to examine a suite of climatic and intrinsic drivers of continental-scale West Nile virus epidemics, including an empirically derived mechanistic relationship between temperature and transmission potential that accounts for spatial variability in vectors. We found that drought was the primary climatic driver of increased West Nile virus epidemics, rather than within-season or winter temperatures, or precipitation independently. Local-scale data from one region suggested drought increased epidemics via changes in mosquito infection prevalence rather than mosquito abundance. In addition, human acquired immunity following regional epidemics limited subsequent transmission in many states. We show that over the next 30 years, increased drought severity from climate change could triple West Nile virus cases, but only in regions with low human immunity. These results illustrate how changes in drought severity can alter the transmission dynamics of vector-borne diseases. © 2017 The Author(s).

Vaccines in development against West Nile virus.

PubMed

Brandler, Samantha; Tangy, Frederic

2013-09-30

West Nile encephalitis emerged in 1999 in the United States, then rapidly spread through the North American continent causing severe disease in human and horses. Since then, outbreaks appeared in Europe, and in 2012, the United States experienced a new severe outbreak reporting a total of 5,387 cases of West Nile virus (WNV) disease in humans, including 243 deaths. So far, no human vaccine is available to control new WNV outbreaks and to avoid worldwide spreading. In this review, we discuss the state-of-the-art of West Nile vaccine development and the potential of a novel safe and effective approach based on recombinant live attenuated measles virus (MV) vaccine. MV vaccine is a live attenuated negative-stranded RNA virus proven as one of the safest, most stable and effective human vaccines. We previously described a vector derived from the Schwarz MV vaccine strain that stably expresses antigens from emerging arboviruses, such as dengue, West Nile or chikungunya viruses, and is strongly immunogenic in animal models, even in the presence of MV pre-existing immunity. A single administration of a recombinant MV vaccine expressing the secreted form of WNV envelope glycoprotein elicited protective immunity in mice and non-human primates as early as two weeks after immunization, indicating its potential as a human vaccine.

Vaccines in Development against West Nile Virus

PubMed Central

Brandler, Samantha; Tangy, Frederic

2013-01-01

West Nile encephalitis emerged in 1999 in the United States, then rapidly spread through the North American continent causing severe disease in human and horses. Since then, outbreaks appeared in Europe, and in 2012, the United States experienced a new severe outbreak reporting a total of 5,387 cases of West Nile virus (WNV) disease in humans, including 243 deaths. So far, no human vaccine is available to control new WNV outbreaks and to avoid worldwide spreading. In this review, we discuss the state-of-the-art of West Nile vaccine development and the potential of a novel safe and effective approach based on recombinant live attenuated measles virus (MV) vaccine. MV vaccine is a live attenuated negative-stranded RNA virus proven as one of the safest, most stable and effective human vaccines. We previously described a vector derived from the Schwarz MV vaccine strain that stably expresses antigens from emerging arboviruses, such as dengue, West Nile or chikungunya viruses, and is strongly immunogenic in animal models, even in the presence of MV pre-existing immunity. A single administration of a recombinant MV vaccine expressing the secreted form of WNV envelope glycoprotein elicited protective immunity in mice and non-human primates as early as two weeks after immunization, indicating its potential as a human vaccine. PMID:24084235

Tracing Nile sediment sources by Sr and Nd isotope signatures (Uganda, Ethiopia, Sudan)

NASA Astrophysics Data System (ADS)

Padoan, Marta; Garzanti, Eduardo; Harlavan, Yehudit; Villa, Igor Maria

2011-06-01

Strontium and neodymium isotopes, measured on diverse mud and sand fractions of sediment in transit along all major Nile branches, identify detritus sourced from Precambrian basements, Mesozoic strata, and Tertiary volcanic rocks exposed along the shoulders of the East African rift and in Ethiopian highlands. Sr and Nd isotopic ratios reflect the weighted average of detrital components generated in different catchments, allowing us to discriminate provenance, calculate sediment budgets, and investigate grain-size and hydraulic-sorting effects. 87Sr/ 86Sr and 143Nd/ 144Nd range, respectively, from as high as 0.722 and as low as 0.5108 for sediment derived from Archean gneisses in northern Uganda, to 0.705 and 0.5127 for sediment derived from Neoproterozoic Ethiopian and Eritrean basements. 87Sr/ 86Sr and 143Nd/ 144Nd, ranging 0.705-0.709 and 0.5124-0.5130 for Blue Nile tributaries, are 0.704-0.705 and 0.5127-0.5128 for largely volcaniclastic sediments of River Tekeze-Atbara, and 0.705-0.706 and 0.5126-0.5127 for main Nile sediments upstream Lake Nasser. Model mantle derivation ages ( tDM), oldest in Uganda where sediment is principally derived from the Congo Craton (3.4-3.0 Ga for Victoria and Albert Nile), progressively decrease northward across the Saharan Metacraton, from 2.6 Ga (Bahr el Jebel in South Sudan), to 2.4-2.2 Ga (Bahr ez Zeraf across the Sudd), and finally 1.6-1.3 Ga (White Nile upstream Khartoum). Instead, tDM ages of Sobat mud increase from 0.9 to 1.5 Ga across the Machar marshes. TDM ages are younger for sediments shed by Ethiopian (1.2-0.7 Ga) and Eritrean basements (1.5-1.2 Ga), and youngest for sediments shed from Ethiopian flood basalts (0.3-0.2 Ga). Integrated geochemical, mineralogical, and settling-equivalence analyses suggest influence on the Nd isotopic signal by volcanic lithic grains and titanite rather than by LREE-rich monazite or allanite. Because contributions by ultradense minerals is subordinate, intrasample variability of Sr and Nd ratios is minor. In Blue Nile, Atbara and main Nile sediments of mixed provenance, however, the Nd ratio tends to be higher and tDM ages lower in largely volcaniclastic mud than in mixed volcaniclastic/metamorphiclastic sand. The complete geochemical database presented here, coupled with high-resolution bulk-petrography and heavy-mineral data, provides a key to reconstructing erosion patterns and detrital fluxes across the whole Nile basin, and to investigate and understand how sources of sediment have changed in the historical and pre-historical past in relation to shifting climatic zones across arid northern Africa.

Organic matter pools, C turnover and meiofaunal biodiversity in the sediments of the western Spitsbergen deep continental margin, Svalbard Archipelago

NASA Astrophysics Data System (ADS)

Pusceddu, A.; Carugati, L.; Gambi, C.; Mienert, J.; Petani, B.; Sanchez-Vidal, A.; Canals, M.; Heussner, S.; Danovaro, R.

2016-01-01

We investigated organic matter (OM) quantity, nutritional quality and degradation rates, as well as abundance and biodiversity of meiofauna and nematodes along the deep continental margin off Spitsbergen, in the Svalbard Archipelago. Sediment samples were collected in July 2010 and 2011 along a bathymetric gradient between 600 m and 2000 m depth, and total mass flux measured at the same depths from July 2010 to July 2011. In both sampling periods sedimentary OM contents and C degradation rates increased significantly with water depth, whereas OM nutritional quality was generally higher at shallower depths, with the unique exception at 600 m depth in 2010. Meiofaunal abundance and biomass (largely dominated by nematodes) showed the highest values at intermediate depths (ca 1500 m) in both sampling periods. The richness of meiofaunal higher taxa and nematode species richness did not vary significantly with water depth in both sampling periods. We suggest here that patterns in OM quantity, C degradation rates, and meiofauna community composition in 2011 were likely influenced by the intensification of the warm West Spitsbergen Current (WSC). We hypothesize that the intensity of the WSC inflow to the Arctic Ocean could have an important role on benthic biodiversity and functioning of deep-sea Arctic ecosystems.

Tilapia show immunization response against Ich

USDA-ARS?s Scientific Manuscript database

This study compares the immune response of Nile tilapia and red tilapia against parasite Ichthyophthirius multifiliis (Ich) using a cohabitation challenge model. Both Nile and red tilapia showed strong immune response post immunization with live Ich theronts by IP injection or immersion. Blood serum...

Evaluation of marginal fit of 2 CAD-CAM anatomic contour zirconia crown systems and lithium disilicate glass-ceramic crown.

PubMed

Ji, Min-Kyung; Park, Ji-Hee; Park, Sang-Won; Yun, Kwi-Dug; Oh, Gye-Jeong; Lim, Hyun-Pil

2015-08-01

This study was to evaluate the marginal fit of two CAD-CAM anatomic contour zirconia crown systems compared to lithium disilicate glass-ceramic crowns. Shoulder and deep chamfer margin were formed on each acrylic resin tooth model of a maxillary first premolar. Two CAD-CAM systems (Prettau®Zirconia and ZENOSTAR®ZR translucent) and lithium disilicate glass ceramic (IPS e.max®press) crowns were made (n=16). Each crown was bonded to stone dies with resin cement (Rely X Unicem). Marginal gap and absolute marginal discrepancy of crowns were measured using a light microscope equipped with a digital camera (Leica DFC295) magnified by a factor of 100. Two-way analysis of variance (ANOVA) and post-hoc Tukey's HSD test were conducted to analyze the significance of crown marginal fit regarding the finish line configuration and the fabrication system. The mean marginal gap of lithium disilicate glass ceramic crowns (IPS e.max®press) was significantly lower than that of the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia) (P<.05). Both fabrication systems and finish line configurations significantly influenced the absolute marginal discrepancy (P<.05). The lithium disilicate glass ceramic crown (IPS e.max®press) had significantly smaller marginal gap than the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia). In terms of absolute marginal discrepancy, the CAD-CAM anatomic contour zirconia crown system (ZENOSTAR®ZR translucent) had under-extended margin, whereas the CAD-CAM anatomic contour zirconia crown system (Prettau®Zirconia) and lithium disilicate glass ceramic crowns (IPS e.max®press) had overextended margins.

Tropical fish in a warming world: thermal tolerance of Nile perch Lates niloticus (L.) in Lake Nabugabo, Uganda.

PubMed

Chrétien, Emmanuelle; Chapman, Lauren J

2016-01-01

Key to predicting the response of fishes to climate change is quantifying how close fish are to their critical thermal limits in nature and their ability to adjust their thermal sensitivity to maintain performance. Here, we evaluated the effects of body size and habitat on aerobic scope (AS) and thermal tolerance of Nile perch Lates niloticus (L.), a fish of great economic and food security importance in East Africa, using respirometry and critical thermal maximum (CTmax) trials. Juvenile Nile perch from distinct habitats (high or low dissolved oxygen concentrations) of Lake Nabugabo, Uganda were exposed for 4.6 ± 0.55 days to a temperature treatment (25.5, 27.5, 29.5 or 31.5°C) prior to experimentation, with the lowest temperature corresponding to the mean annual daytime temperature in Lake Nabugabo and the highest temperature being 3°C higher than the maximal monthly average. As expected, metabolic rates increased with body mass. Although resting metabolic rate increased with temperature, maximal metabolic rate showed no change. Likewise, AS did not vary across treatments. The CTmax increased with acclimation temperature. There was no effect of habitat on maximal metabolic rate, AS or CTmax; however, there was a trend towards a lower resting metabolic rate for Nile perch captured in the low-dissolved oxygen habitat than in well-oxygenated waters. This study shows that juvenile Nile perch maintain a large AS at temperatures near the upper limit of their natural thermal range and provides evidence that Nile perch have physiological mechanisms to deal with acute exposure to thermal stress.

Survival, growth and reproduction of non-native Nile tilapia II: fundamental niche projections and invasion potential in the northern Gulf of Mexico.

PubMed

Lowe, Michael R; Wu, Wei; Peterson, Mark S; Brown-Peterson, Nancy J; Slack, William T; Schofield, Pamela J

2012-01-01

Understanding the fundamental niche of invasive species facilitates our ability to predict both dispersal patterns and invasion success and therefore provides the basis for better-informed conservation and management policies. Here we focus on Nile tilapia (Oreochromis niloticus Linnaeus, 1758), one of the most widely cultured fish worldwide and a species that has escaped local aquaculture facilities to become established in a coastal-draining river in Mississippi (northern Gulf of Mexico). Using empirical physiological data, logistic regression models were developed to predict the probabilities of Nile tilapia survival, growth, and reproduction at different combinations of temperature (14 and 30°C) and salinity (0-60, by increments of 10). These predictive models were combined with kriged seasonal salinity data derived from multiple long-term data sets to project the species' fundamental niche in Mississippi coastal waters during normal salinity years (averaged across all years) and salinity patterns in extremely wet and dry years (which might emerge more frequently under scenarios of climate change). The derived fundamental niche projections showed that during the summer, Nile tilapia is capable of surviving throughout Mississippi's coastal waters but growth and reproduction were limited to river mouths (or upriver). Overwinter survival was also limited to river mouths. The areas where Nile tilapia could survive, grow, and reproduce increased during extremely wet years (2-368%) and decreased during extremely dry years (86-92%) in the summer with a similar pattern holding for overwinter survival. These results indicate that Nile tilapia is capable of 1) using saline waters to gain access to other watersheds throughout the region and 2) establishing populations in nearshore, low-salinity waters, particularly in the western portion of coastal Mississippi.

Impact of climate change on precipitation distribution and water availability in the Nile using CMIP5 GCM ensemble.

NASA Astrophysics Data System (ADS)

Mekonnen, Z. T.; Gebremichael, M.

2017-12-01

ABSTRACT In a basin like the Nile where millions of people depend on rainfed agriculture and surface water resources for their livelihoods, changes in precipitation will have tremendous social and economic consequences. General circulation models (GCMs) have been associated with high uncertainty in their projection of future precipitation for the Nile basin. Some studies tried to compare performance of different GCMs by doing a Multi-Model comparison for the region. Many indicated that there is no single model that gives the "best estimate" of precipitation for a very complex and large basin like the Nile. In this study, we used a combination of satellite and long term rain gauge precipitation measurements (TRMM and CenTrends) to evaluate the performance of 10 GCMs from the 5th Coupled Model Intercomparison Project (CMIP5) at different spatial and seasonal scales and produce a weighted ensemble projection. Our results confirm that there is no single model that gives best estimate over the region, hence the approach of creating an ensemble depending on how the model performed in specific areas and seasons resulted in an improved estimate of precipitation compared with observed values. Following the same approach, we created an ensemble of future precipitation projections for four different time periods (2000-2024, 2025-2049 and 2050-2100). The analysis showed that all the major sub-basins of the Nile will get will get more precipitation with time, even though the distribution with in the sub basin might be different. Overall the analysis showed a 15 % increase (125 mm/year) by the end of the century averaged over the area up to the Aswan dam. KEY WORDS: Climate Change, CMIP5, Nile, East Africa, CenTrends, Precipitation, Weighted Ensembles

Vulnerability of the Nile Delta coastal areas to inundation by sea level rise.

PubMed

Hassaan, M A; Abdrabo, M A

2013-08-01

Sea level changes are typically caused by several natural phenomena, including ocean thermal expansion, glacial melt from Greenland and Antarctica. Global average sea level is expected to rise, through the twenty-first century, according to the IPCC projections by between 0.18 and 0.59 cm. Such a rise in sea level will significantly impact coastal area of the Nile Delta, consisting generally of lowland and is densely populated areas and accommodates significant proportion of Egypt's economic activities and built-up areas. The Nile Delta has been examined in several previous studies, which worked under various hypothetical sea level rise (SLR) scenarios and provided different estimates of areas susceptible to inundation due to SLR. The paper intends, in this respect, to identify areas, as well as land use/land cover, susceptible to inundation by SLR based upon most recent scenarios of SLR, by the year 2100 using GIS. The results indicate that about 22.49, 42.18, and 49.22 % of the total area of coastal governorates of the Nile Delta would be susceptible to inundation under different scenarios of SLR. Also, it was found that 15.56 % of the total areas of the Nile Delta that would be vulnerable to inundation due to land subsidence only, even in the absence of any rise in sea level. Moreover, it was found that a considerable proportion of these areas (ranging between 32.32 and 53.66 %) are currently either wetland or undeveloped areas. Furthermore, natural and/or man-made structures, such as the banks of the International Coastal Highway, were found to provide unintended protection to some of these areas. This suggests that the inundation impact of SLR on the Nile Delta is less than previously reported.

Tropical fish in a warming world: thermal tolerance of Nile perch Lates niloticus (L.) in Lake Nabugabo, Uganda

PubMed Central

Chrétien, Emmanuelle; Chapman, Lauren J.

2016-01-01

Key to predicting the response of fishes to climate change is quantifying how close fish are to their critical thermal limits in nature and their ability to adjust their thermal sensitivity to maintain performance. Here, we evaluated the effects of body size and habitat on aerobic scope (AS) and thermal tolerance of Nile perch Lates niloticus (L.), a fish of great economic and food security importance in East Africa, using respirometry and critical thermal maximum (CTmax) trials. Juvenile Nile perch from distinct habitats (high or low dissolved oxygen concentrations) of Lake Nabugabo, Uganda were exposed for 4.6 ± 0.55 days to a temperature treatment (25.5, 27.5, 29.5 or 31.5°C) prior to experimentation, with the lowest temperature corresponding to the mean annual daytime temperature in Lake Nabugabo and the highest temperature being 3°C higher than the maximal monthly average. As expected, metabolic rates increased with body mass. Although resting metabolic rate increased with temperature, maximal metabolic rate showed no change. Likewise, AS did not vary across treatments. The CTmax increased with acclimation temperature. There was no effect of habitat on maximal metabolic rate, AS or CTmax; however, there was a trend towards a lower resting metabolic rate for Nile perch captured in the low-dissolved oxygen habitat than in well-oxygenated waters. This study shows that juvenile Nile perch maintain a large AS at temperatures near the upper limit of their natural thermal range and provides evidence that Nile perch have physiological mechanisms to deal with acute exposure to thermal stress. PMID:27990290

Hydro-economic Risk Assessment in the Eastern Nile River Basin

NASA Astrophysics Data System (ADS)

Arjoon, D.; Tilmant, A.; Mohamed, Y.

2013-12-01

In 2011, the Ethiopian government announced plans for the construction of the Grand Renaissance Dam (GRD) on the Blue Nile, just east of its border with Sudan, at a cost of almost 5 billion dollars. The project is expected to generate over 15 TWh of energy and will include a reservoir of more than 60 km3 capacity, which roughly corresponds to the average annual flow of the Blue Nile. This project is part of a larger scheme, by the government, to expand its hydroelectric power capacity, however, the scheme faces strong opposition from downstream Egypt and Sudan. Egypt and Sudan are highly dependent on flows that originate in Ethiopia (it has been estimated that 86% of Nile flow originates in the Ethiopian highlands). The Ethiopian government argues that the dam would supply electricity for Ethiopians as well as generate surplus energy for export to neighboring countries. The Ethiopians also argue that the huge reservoir would generate positive externalities downstream by reducing floods and providing more constant and predictable lows. This study attempts to provide an independent analysis of the hydrologic and economic risks faced by downstream countries when GRD will be online. To achieve this, an integrated, stochastic hydro-economic model of the entire Eastern Nile basin is used to analyze various development and management scenarios. The results indicate that if countries agree to co- operative management of the Eastern Nile River basin, GRD would indeed significantly increase basin-wide benefits, especially in Ethiopia and in Sudan. An alternative management scenario, whereby GRD would be operated by Sudan and Egypt, does not yield significant economic gains in these countries. However, massive unilateral irrigation developments in Ethiopia will be detrimental for all countries, including Ethiopia itself, due to the huge opportunity costs involved.

West Nile virus: Uganda, 1937, to New York City, 1999.

PubMed

Hayes, C G

2001-12-01

West Nile virus, first isolated in 1937, is among the earliest arthropod-borne viruses discovered by humans. Its broad geographical distribution, not uncommon infection of humans, transmission by mosquitoes, and association with wild birds as enzootic hosts were well documented by the mid-1960s. However, West Nile virus was not considered to be a significant human pathogen because most infections appeared to result in asymptomatic or only mild febrile disease. Several epidemics had been documented prior to 1996, some involving hundreds to thousands of cases in mostly rural populations, but only a few cases of severe neurological disease had been reported. The occurrence between 1996 and 1999 of three major epidemics, in southern Romania, the Volga delta in southern Russia, and the northeastern United States, involving hundreds of cases of severe neurological disease and fatal infections was totally unexpected. These were the first epidemics reported in large urban populations. A significant factor that appeared in common to all three outbreaks was the apparent involvement of the common house mosquito, Culex pipiens, as a vector. This species had not previously been implicated as important in the transmission of West Nile virus. In addition the epidemic in the northeastern United States was unusual in the association of West Nile virus infection with fatal disease of birds, suggesting a change in the virulence of the virus toward this host. Understanding the risk factors that contributed to these three urban epidemics is important for minimizing the potential for future occurrences. This review will attempt to compare observations on the biology of West Nile virus made over about 60 years prior to the recent epidemics to observations made in association with these urban epidemics.

Survival, Growth and Reproduction of Non-Native Nile Tilapia II: Fundamental Niche Projections and Invasion Potential in the Northern Gulf of Mexico

PubMed Central

Lowe, Michael R.; Wu, Wei; Peterson, Mark S.; Brown-Peterson, Nancy J.; Slack, William T.; Schofield, Pamela J.

2012-01-01

Understanding the fundamental niche of invasive species facilitates our ability to predict both dispersal patterns and invasion success and therefore provides the basis for better-informed conservation and management policies. Here we focus on Nile tilapia (Oreochromis niloticus Linnaeus, 1758), one of the most widely cultured fish worldwide and a species that has escaped local aquaculture facilities to become established in a coastal-draining river in Mississippi (northern Gulf of Mexico). Using empirical physiological data, logistic regression models were developed to predict the probabilities of Nile tilapia survival, growth, and reproduction at different combinations of temperature (14 and 30°C) and salinity (0–60, by increments of 10). These predictive models were combined with kriged seasonal salinity data derived from multiple long-term data sets to project the species' fundamental niche in Mississippi coastal waters during normal salinity years (averaged across all years) and salinity patterns in extremely wet and dry years (which might emerge more frequently under scenarios of climate change). The derived fundamental niche projections showed that during the summer, Nile tilapia is capable of surviving throughout Mississippi's coastal waters but growth and reproduction were limited to river mouths (or upriver). Overwinter survival was also limited to river mouths. The areas where Nile tilapia could survive, grow, and reproduce increased during extremely wet years (2–368%) and decreased during extremely dry years (86–92%) in the summer with a similar pattern holding for overwinter survival. These results indicate that Nile tilapia is capable of 1) using saline waters to gain access to other watersheds throughout the region and 2) establishing populations in nearshore, low-salinity waters, particularly in the western portion of coastal Mississippi. PMID:22848533

Soil aggregate stability and wind erodible fraction in a semi-arid environment of White Nile State, Sudan

NASA Astrophysics Data System (ADS)

Elhaja, Mohamed Eltom; Ibrahim, Ibrahim Saeed; Adam, Hassan Elnour; Csaplovics, Elmar

2014-11-01

One of the most important recent issues facing White Nile State, Sudan, as well as Sub Saharan Africa, is the threat of continued land degradation and desertification as a result of climatic factors and human activities. Remote sensing and satellites imageries with multi-temporal and spectral and GIS capability, plays a major role in developing a global and local operational capability for monitoring land degradation and desertification in dry lands, as well as in White Nile State. The process of desertification in form of sand encroachment in White Nile State has increased rapidly, and much effort has been devoted to define and study its causes and impacts. This study depicts the capability afforded by remote sensing and GIS to analyze and map the aggregate stability as indicator for the ability of soil to wind erosion process in White Nile State by using Geo-statistical techniques. Cloud-free subset Landsat; Enhance Thematic Mapper plus (ETM +) scenes covering the study area dated 2008 was selected in order to identify the different features covering the study area as well as to make the soil sampling map. Wet-sieving method was applied to determine the aggregate stability. The geo-statistical methods in EARDAS 9.1 software was used for mapping the aggregate stability. The results showed that the percentage of aggregate stability ranged from (0 to 61%) in the study area, which emphasized the phenomena of sand encroachment from the western part (North Kordofan) to the eastern part (White Nile State), following the wind direction. The study comes out with some valuable recommendations and comments, which could contribute positively in reducing sand encroachments

Survival, growth and reproduction of non-native Nile tilapia II: fundamental niche projections and invasion potential in the northern Gulf of Mexico

USGS Publications Warehouse

Lowe, Michael R.; Wu, Wei; Peterson, Mark S.; Brown-Peterson, Nancy J.; Slack, William T.; Schofield, Pamela J.

2012-01-01

Understanding the fundamental niche of invasive species facilitates our ability to predict both dispersal patterns and invasion success and therefore provides the basis for better-informed conservation and management policies. Here we focus on Nile tilapia (Oreochromis niloticus Linnaeus, 1758), one of the most widely cultured fish worldwide and a species that has escaped local aquaculture facilities to become established in a coastal-draining river in Mississippi (northern Gulf of Mexico). Using empirical physiological data, logistic regression models were developed to predict the probabilities of Nile tilapia survival, growth, and reproduction at different combinations of temperature (14 and 30°C) and salinity (0–60, by increments of 10). These predictive models were combined with kriged seasonal salinity data derived from multiple long-term data sets to project the species' fundamental niche in Mississippi coastal waters during normal salinity years (averaged across all years) and salinity patterns in extremely wet and dry years (which might emerge more frequently under scenarios of climate change). The derived fundamental niche projections showed that during the summer, Nile tilapia is capable of surviving throughout Mississippi's coastal waters but growth and reproduction were limited to river mouths (or upriver). Overwinter survival was also limited to river mouths. The areas where Nile tilapia could survive, grow, and reproduce increased during extremely wet years (2–368%) and decreased during extremely dry years (86–92%) in the summer with a similar pattern holding for overwinter survival. These results indicate that Nile tilapia is capable of 1) using saline waters to gain access to other watersheds throughout the region and 2) establishing populations in nearshore, low-salinity waters, particularly in the western portion of coastal Mississippi.

Egypt, Nile Valley, Gulf of Suez, Sinai as seen from Gemini 12 spacecraft

NASA Image and Video Library

1966-11-13

S66-63477 (13 Nov. 1966) --- United Arab Republic (Egypt), the Nile Valley from Luxor to Cairo, El Payium, Gulf of Suez, Sinai as seen from Gemini-12 spacecraft on its 25th revolution of Earth. Photo credit: NASA

West Nile Virus in Farmed Alligators

PubMed Central

Mauel, Michael J.; Baldwin, Charles; Burtle, Gary; Ingram, Dallas; Hines, Murray E.; Frazier, Kendal S.

2003-01-01

Seven alligators were submitted to the Tifton Veterinary Diagnostic and Investigational Laboratory for necropsy during two epizootics in the fall of 2001 and 2002. The alligators were raised in temperature-controlled buildings and fed a diet of horsemeat supplemented with vitamins and minerals. Histologic findings in the juvenile alligators were multiorgan necrosis, heterophilic granulomas, and heterophilic perivasculitis and were most indicative of septicemia or bacteremia. Histologic findings in a hatchling alligator were random foci of necrosis in multiple organs and mononuclear perivascular encephalitis, indicative of a viral cause. West Nile virus was isolated from submissions in 2002. Reverse transcription-polymerase chain reaction (RT-PCR) results on all submitted case samples were positive for West Nile virus for one of four cases associated with the 2001 epizootic and three of three cases associated with the 2002 epizootic. RT-PCR analysis was positive for West Nile virus in the horsemeat collected during the 2002 outbreak but negative in the horsemeat collected after the outbreak. PMID:12890319

C. elegans Major Fats Are Stored in Vesicles Distinct from Lysosome-Related Organelles

PubMed Central

O’Rourke, Eyleen J.; Soukas, Alexander A.; Carr, Christopher E.; Ruvkun, Gary

2010-01-01

SUMMARY Genetic conservation allows ancient features of fat storage endocrine pathways to be explored in C. elegans. Multiple studies have used Nile red or BODIPY-labeled fatty acids to identify regulators of fat mass. When mixed with their food, E. coli bacteria, Nile red, and BODIPY-labeled fatty acids stain multiple spherical cellular structures in the C. elegans major fat storage organ, the intestine. However, here we demonstrate that, in the conditions previously reported, the lysosome-related organelles stained by Nile red and BODIPY-labeled fatty acids are not the C. elegans major fat storage compartment. We show that the major fat stores are contained in a distinct cellular compartment that is not stained by Nile red. Using biochemical assays, we validate oil red O staining as a method to assess major fat stores in C. elegans, allowing for efficient and accurate genetic and functional genomic screens for genes that control fat accumulation at the organismal level. PMID:19883620

Reduced West Nile Virus Transmission Around Communal Roosts of Great-Tailed Grackle (Quiscalus mexicanus)

PubMed Central

Komar, Nicholas; Colborn, James M.; Horiuchi, Kalanthe; Delorey, Mark; Biggerstaff, Brad; Damian, Dan; Smith, Kirk; Townsend, John

2016-01-01

West Nile virus has caused several outbreaks among humans in the Phoenix metropolitan area (Arizona, southwest USA) within the last decade. Recent ecologic studies have implicated Culex quinquefasciatus and Culex tarsalis as the mosquito vectors and identified three abundant passerine birds—great-tailed grackle (Quiscalus mexicanus), house sparrow (Passer domesticus), and house finch (Haemorhous mexicanus)—as key amplifiers among vertebrates. Nocturnal congregations of certain species have been suggested as critical for late summer West Nile virus amplification. We evaluated the hypothesis that house sparrow (P. domesticus) and/or great-tailed grackle (Q. mexicanus) communal roost sites (n = 22 and n = 5, respectively) in a primarily suburban environment were spatially associated with West Nile virus transmission indices during the 2010 outbreak of human neurological disease in metropolitan Phoenix. Spatial associations between human case residences and communal roosts were non-significant for house sparrows, and were negative for great-tailed grackle. Several theories that explain these observations are discussed, including the possibility that grackle communal roosts are protective. PMID:25480320

Isolation and molecular identification of Naegleria fowleri from Nile river, Egypt.

PubMed

Al-Herrawy, Ahmad Z; Gad, Mahmoud A

2015-12-01

Members of the genus Naegleria are free-living amoebae distributed in various aquatic environments. Naegleria fowleri is the only species that can cause fatal primary amoebic meningoencephalitis in humans. A total of 48 Nile water samples were collected from the water stream passing though Cairo. The samples were processed for the detection of Naegleria spp. using non-nutrient agar at 45°C. The isolates of Naegleria spp. were identified based on the morphologic criteria of trophozoite, flagellated and cyst stages. Molecular characterization of the isolates was performed using PCR. The obtained results showed that Naegleria spp. were found in 45.8% of Nile water samples by means of microscopic examination. Seasonally, the highest prevalence of Naegleria spp. was recorded in summer (66.7%). Moreover, the highest prevalence of N. fowleri was recorded in summer (25%). The occurrence of heat-tolerant Naegleria spp., especially N. fowleri, in Nile water should be considered as a potential health threat.

A high-resolution map of the Nile tilapia genome: a resource for studying cichlids and other percomorphs

PubMed Central

2012-01-01

Background The Nile tilapia (Oreochromis niloticus) is the second most farmed fish species worldwide. It is also an important model for studies of fish physiology, particularly because of its broad tolerance to an array of environments. It is a good model to study evolutionary mechanisms in vertebrates, because of its close relationship to haplochromine cichlids, which have undergone rapid speciation in East Africa. The existing genomic resources for Nile tilapia include a genetic map, BAC end sequences and ESTs, but comparative genome analysis and maps of quantitative trait loci (QTL) are still limited. Results We have constructed a high-resolution radiation hybrid (RH) panel for the Nile tilapia and genotyped 1358 markers consisting of 850 genes, 82 markers corresponding to BAC end sequences, 154 microsatellites and 272 single nucleotide polymorphisms (SNPs). From these, 1296 markers could be associated in 81 RH groups, while 62 were not linked. The total size of the RH map is 34,084 cR3500 and 937,310 kb. It covers 88% of the entire genome with an estimated inter-marker distance of 742 Kb. Mapping of microsatellites enabled integration to the genetic map. We have merged LG8 and LG24 into a single linkage group, and confirmed that LG16-LG21 are also merged. The orientation and association of RH groups to each chromosome and LG was confirmed by chromosomal in situ hybridizations (FISH) of 55 BACs. Fifty RH groups were localized on the 22 chromosomes while 31 remained small orphan groups. Synteny relationships were determined between Nile tilapia, stickleback, medaka and pufferfish. Conclusion The RH map and associated FISH map provide a valuable gene-ordered resource for gene mapping and QTL studies. All genetic linkage groups with their corresponding RH groups now have a corresponding chromosome which can be identified in the karyotype. Placement of conserved segments indicated that multiple inter-chromosomal rearrangements have occurred between Nile tilapia and the other model fishes. These maps represent a valuable resource for organizing the forthcoming genome sequence of Nile tilapia, and provide a foundation for evolutionary studies of East African cichlid fishes. PMID:22672252

Ampullariid gastropods from the Palaeogene Hudi Chert Formation (Republic of the Sudan)

NASA Astrophysics Data System (ADS)

Harzhauser, Mathias; Neubauer, Thomas A.; Bussert, Robert; Eisawi, Ali A. M.

2017-05-01

The age of the Hudi Chert fauna is highly controversial and crucial for the reconstruction of the geological history of the Nile valley. Herein, six species of Ampullariidae (Gastropoda) are described from the Hudi Chert Formation in the Republic of the Sudan, documenting that alleged relations of the Hudi Chert fauna with Oligocene faunas from Egypt turned out to be based on misidentifications. Although an Oligocene age cannot be excluded, we propose an Eocene age for the Hudi Chert fauna based on the known stratigraphic range of the newly established genus Sudanistes. A Neogene age is clearly excluded based on the presence of the exclusively Palaeogene genus Pseudoceratodus. The Hudi Chert ampullariids lived in an extensive freshwater system of swamps and ponds, whereas riverine conditions and deep lake setting are unlikely depositional environments. Pila busserti Harzhauser & Neubauer is described as a new species and Sudanistes Harzhauser & Neubauer is introduced as a new genus.

Re-appraisal of the Magma-rich versus Magma-poor Paradigm at Rifted Margins: consequences for breakup processes

NASA Astrophysics Data System (ADS)

Tugend, J.; Gillard, M.; Manatschal, G.; Nirrengarten, M.; Harkin, C. J.; Epin, M. E.; Sauter, D.; Autin, J.; Kusznir, N. J.; McDermott, K.

2017-12-01

Rifted margins are often classified based on their magmatic budget only. Magma-rich margins are commonly considered to have excess decompression melting at lithospheric breakup compared with steady state seafloor spreading while magma-poor margins have suppressed melting. New observations derived from high quality geophysical data sets and drill-hole data have revealed the diversity of rifted margin architecture and variable distribution of magmatism. Recent studies suggest, however, that rifted margins have more complex and polyphase tectono-magmatic evolutions than previously assumed and cannot be characterized based on the observed volume of magma alone. We compare the magmatic budget related to lithospheric breakup along two high-resolution long-offset deep reflection seismic profiles across the SE-Indian (magma-poor) and Uruguayan (magma-rich) rifted margins. Resolving the volume of magmatic additions is difficult. Interpretations are non-unique and several of them appear plausible for each case involving variable magmatic volumes and mechanisms to achieve lithospheric breakup. A supposedly 'magma-poor' rifted margin (SE-India) may show a 'magma-rich' lithospheric breakup whereas a 'magma-rich' rifted margin (Uruguay) does not necessarily show excess magmatism at lithospheric breakup compared with steady-state seafloor spreading. This questions the paradigm that rifted margins can be subdivided in either magma-poor or magma-rich margins. The Uruguayan and other magma-rich rifted margins appear characterized by an early onset of decompression melting relative to crustal breakup. For the converse, where the onset of decompression melting is late compared with the timing of crustal breakup, mantle exhumation can occur (e.g. SE-India). Our work highlights the difficulty in determining a magmatic budget at rifted margins based on seismic reflection data alone, showing the limitations of margin classification based solely on magmatic volumes. The timing of decompression melting onset and melting rates (magmatic processes) relative to crustal thinning (tectonic processes) appear equally, if not more important, than the magmatic budget for unravelling the evolution of rifted margins.

The Role of Innate Immunity in Conditioning Mosquito Susceptibility to West Nile Virus

PubMed Central

Prasad, Abhishek N.; Brackney, Doug. E.; Ebel, Gregory D.

2013-01-01

Arthropod-borne viruses (arboviruses) represent an emerging threat to human and livestock health globally. In particular, those transmitted by mosquitoes present the greatest challenges to disease control efforts. An understanding of the molecular basis for mosquito innate immunity to arbovirus infection is therefore critical to investigations regarding arbovirus evolution, virus-vector ecology, and mosquito vector competence. In this review, we discuss the current state of understanding regarding mosquito innate immunity to West Nile virus. We draw from the literature with respect to other virus-vector pairings to attempt to draw inferences to gaps in our knowledge about West Nile virus and relevant vectors. PMID:24351797

Fatal West Nile virus infection in a white-tailed deer (Odocoileus virginianus).

PubMed

Miller, Debra L; Radi, Zaher A; Baldwin, Charles; Ingram, Dallas

2005-01-01

A 3-yr-old male white-tailed deer (Odocoileus virginianus) with a history of ataxia and tremors was submitted to the Tifton Veterinary Diagnostic and Investigational Laboratory (The University of Georgia, Tifton, Georgia, USA) for necropsy. Gross findings were unremarkable. Histologically, the brain had multifocal lymphoplasmacytic perivascular inflammation, scattered gliosis, and rare satellitosis. Mild hemorrhage and congestion in the retropharyngeal lymph nodes and mild lymphoid depletion in the tonsil were present. A reverse transcription-polymerase chain reaction test performed on brain yielded a positive result for West Nile virus. This represents the first report of fatal West Nile virus infection in a white-tailed deer.

Adult-onset opsoclonus-myoclonus syndrome due to West Nile Virus treated with intravenous immunoglobulin.

PubMed

Hébert, Julien; Armstrong, David; Daneman, Nick; Jain, Jennifer Deborah; Perry, James

2017-02-01

A 63-year-old female with no significant past medical history was presented with a 5-day history of progressive opsoclonus-myoclonus, headaches, and fevers. Her workup was significant only for positive West-Nile Virus serum serologies. She received a 2-day course of intravenous immunoglobulin (IvIG). At an 8-week follow up, she had a complete neurological remission. Adult-onset opsoclonus-myoclonus syndrome is a rare condition for which paraneoplastic and infectious causes have been attributed. To our knowledge, this is the first case reported of opsoclonus-myoclonus secondary to West-Nile Virus treated with intravenous immunoglobulin monotherapy.

Crustal seismic velocity structure from Eratosthenes Seamount to Hecataeus Rise across the Cyprus Arc, eastern Mediterranean

NASA Astrophysics Data System (ADS)

Welford, J. Kim; Hall, Jeremy; Hübscher, Christian; Reiche, Sönke; Louden, Keith

2015-02-01

Wide-angle reflection/refraction seismic profiles were recorded across the Cyprus Arc, the plate boundary between the African Plate and the Aegean-Anatolian microplate, from the Eratosthenes Seamount to the Hecataeus Rise immediately south of Cyprus. The resultant models were able to resolve detail of significant lateral velocity variations, though the deepest crust and Moho are not well resolved from the seismic data alone. Conclusions from the modelling suggest that (i) Eratosthenes Seamount consists of continental crust but exhibits a laterally variable velocity structure with a thicker middle crust and thinner lower crust to the northeast; (ii) the Hecataeus Rise has a thick sedimentary rock cover on an indeterminate crust (likely continental) and the crust is significantly thinner than Eratosthenes Seamount based on gravity modelling; (iii) high velocity basement blocks, coincident with highs in the magnetic field, occur in the deep water between Eratosthenes and Hecataeus, and are separated and bounded by deep low-velocity troughs and (iv) one of the high velocity blocks runs parallel to the Cyprus Arc, while the other two appear linked based on the magnetic data and run NW-SE, parallel to the margin of the Hecataeus Rise. The high velocity block beneath the edge of Eratosthenes Seamount is interpreted as an older magmatic intrusion while the linked high velocity blocks along Hecataeus Rise are interpreted as deformed remnant Tethyan oceanic crust or mafic intrusives from the NNW-SSE oriented transform margin marking the northern boundary of Eratosthenes Seamount. Eratosthenes Seamount, the northwestern limit of rifted continental crust from the Levant Margin, is part of a jagged rifted margin transected by transform faults on the northern edge of the lower African Plate that is being obliquely subducted under the Aegean-Anatolian upper plate. The thicker crust of Eratosthenes Seamount may be acting as an asperity on the subducting slab, locally locking up subduction of the Cyprus Arc on its northern margin, while deformed Tethyan oceanic crust remains trapped between its northeastern margin and the Hecataeus Rise.

The Zambezi sedimentary system (coastal plain - deep sea fan): a record of the vertical movements of the Mozambican margin since Cretaceous times.

NASA Astrophysics Data System (ADS)

Ponte, Jean Pierre; Robin, Cecile; Guillocheau, Francois; Baby, Guillaume; Dall'Asta, Massimo; Popescu, Speranta; Suc, Jean Pierre; Droz, Laurence; Rabineau, Marina; Moulin, Maryline

2016-04-01

The Mozambique margin is an oblique to transform margin which feeds one of the largest African turbiditic system, the Zambezi deep-sea fan (1800 km length and 400 km wide; Droz and Mougenot., AAPG Bull., 1987). The Zambezi sedimentary system is characterized by (1) a changing catchment area through time with evidences of river captures (Thomas and Shaw, J. Afr. Earth. Sci, 1988) and (2) a delta, storing more than 12 km of sediment, with no gravitary tectonics. The aim of this study is to carry out a source to sink study along the Zambezi sedimentary system and to analyse the margin evolution (vertical movements, climate change) since Early Cretaceous times. The used data are seismic lines (industrial and academic) and petroleum wells (with access to the cuttings). Our first objective was to perform a new biochronostratigraphic framework based on nannofossils, foraminifers, pollen and spores on the cuttings of three industrial wells. The second target was to recognize the different steps of the growth of the Zambezi sedimentary systems. Four main phases were identified: • Late Jurassic (?) - early Late Cretaceous: from Neocomian to Aptian times, the high of the clinoforms is getting higher, with the first occurrence of contouritic ridges during Aptian times. • Late Cretaceous - Early Paleocene: a major drop of relative sea-level occurred as a consequence of the South African Plateau uplift. The occurrence of two depocenters suggests siliciclastic supplies from the Bushveld and from the North Mozambique domain. • Early Paleocene - Eocene: growth of carbonate platforms and large contouritic ridges. • Oligocene - Present-day: birth of the modern Zambezi Delta, with quite low siliciclastic supply during Oligocene times, increasing during Miocene times. As previously expected (Droz and Mougenot) some sediments of the so-called Zambezi fans are coming from a feeder located east of the Davie Ridge. This study was founded by TOTAL and IFREMER in the frame of the research project PAMELA (Passive Margin Exploration Laboratories).

Climate Influence on Deep Sea Populations

PubMed Central

Company, Joan B.; Puig, Pere; Sardà, Francesc; Palanques, Albert; Latasa, Mikel; Scharek, Renate

2008-01-01

Dynamics of biological processes on the deep-sea floor are traditionally thought to be controlled by vertical sinking of particles from the euphotic zone at a seasonal scale. However, little is known about the influence of lateral particle transport from continental margins to deep-sea ecosystems. To address this question, we report here how the formation of dense shelf waters and their subsequent downslope cascade, a climate induced phenomenon, affects the population of the deep-sea shrimp Aristeus antennatus. We found evidence that strong currents associated with intense cascading events correlates with the disappearance of this species from its fishing grounds, producing a temporary fishery collapse. Despite this initial negative effect, landings increase between 3 and 5 years after these major events, preceded by an increase of juveniles. The transport of particulate organic matter associated with cascading appears to enhance the recruitment of this deep-sea living resource, apparently mitigating the general trend of overexploitation. Because cascade of dense water from continental shelves is a global phenomenon, we anticipate that its influence on deep-sea ecosystems and fisheries worldwide should be larger than previously thought. PMID:18197243

Discover the Nile River

ERIC Educational Resources Information Center

Project WET Foundation, 2009

2009-01-01

Bordering on the Fantastic. As the longest river on earth, the Nile passes through 10 countries. Presented through a wide range of activities and a winning array of games, it's also unsurpassed at taking young minds into exploring the world of water, as well as natural and man made wonders.

Modeling the Impact of controlled flow and sediment releases for the restoration of the Nile Delta, Egypt

NASA Astrophysics Data System (ADS)

Al-Zaidi, B. M.; Moussa, A.; Viparelli, E.

2017-12-01

The construction of the High and Old Aswan Dams and of barrages significantly altered the flow and the sediment transport regimes in the Egyptian reach of the Nile River. The field data collected by the Nile Research Institute show that the post-High Aswan Dam Nile River hydrology is characterized by reductions of more than 70% in flow discharge and 98% in sediment load compared to pre-High Aswan Dam conditions. A significant portion of discharge released from the dams is diverted at the barrages for agricultural ( 80%) and municipal ( 15%) uses. Thus, virtually no water is reaching the Nile Delta and the Mediterranean Sea. Consequently, the sediment load delivered to the Mediterranean Sea is negligible compared to pre-dam conditions. Consequences of the flow regulation are delta wide wetland loss and shoreline retreat, widespread delta pollution, reduction soil quality, salination of cultivated land, wetland losses, and saltwater intrusion in the groundwater. Here we present the second part of a feasibility study for the restoration of the Nile River-Delta system characterized by controlled flow releases and sediment augmentations downstream of the High Aswan Dam. The controlled flow releases are obtained by regulating the current releases from the High Aswan Dam at the Old Aswan Dam, which is located 6.5 km downstream of the High Aswan Dam. Previous studies showed that 10 billion m3 of water can be saved annually by improving the Egyptian irrigation system. Here we propose to use the saved water to increase the water discharge to the Nile Delta, i.e., the total volume of water released from the dams does not change, what changes is the water used and the imposed hydrograph. We modulate the river flow by storing the saved water during the agriculture season upstream of the Old Aswan Dam and releasing it in the months coinciding with the natural river flood season. It is important to note that here we are considering the simplest possible scenario for water storage. In reality, additional storage volumes are available upstream of the major barrages, and these volumes can also be used during the proposed restoration project. The study consists in the implementation and validation of a laterally averaged delta growth model to quantify the impact of the proposed restoration project on the Nile Delta in terms of changes in shoreline position and channel-floodplain characteristics under the predicted rates of sea level rise.

Monitoring infiltration and recharge of playa lakes in the Texas Southern High Plains

USDA-ARS?s Scientific Manuscript database

Preliminary results from playa lakes monitored by the Texas Water Development Board (TWDB) suggest that a small volume of deep infiltration and recharge to the Ogallala aquifer occurs along the margins of the lake beds, while the majority of infiltration associated with a typical inundation remains ...

Modulatory role of dietary Chlorella vulgaris powder against arsenic-induced immunotoxicity and oxidative stress in Nile tilapia (Oreochromis niloticus).

PubMed

Zahran, Eman; Risha, Engy

2014-12-01

Arsenic intoxicant have long been regarded as an impending carcinogenic, genotoxic, and immunotoxic heavy metal to human and animals as well. In this respect, we evaluated biomarkers of the innate immune response and oxidative stress metabolism in gills and liver of Nile tilapia (Oreochromis niloticus) after arsenic exposure, and the protective role of Chlorella vulgaris (Ch) dietary supplementation were elucidated. Protective role of C. vulgaris (Ch), as supplementary feeds (5% and 10% of the diet) was studied in Nile tilapia (O. niloticus) against arsenic induced toxicity (NaAsO2 at 7 ppm) for 21 days exposure period. A significant down-regulation in innate immune response; including, respiratory burst, lysozyme, and bactericidal activity followed due to deliberately As(+3) exposure. Similarly, oxidative stress response; like nitric oxide (NO), catalase (CAT), glutathione (GSH), glutathione peroxidase (GPx), malondialdehyde (MDA) and hydrogen peroxide (H2O2) levels were significantly decreased. Combined treatment of Ch and As(+3) significantly enhanced the innate immune response and antioxidant activity. Strikingly, Ch supplementation at 10% has been considered the optimum for Nile tilapia since it exhibited enhancement of innate immune response and antioxidant activity over the level 5%, and even better than that of control level. Thus, our results concluded that dietary Ch supplementation could protect Nile tilapia against arsenic induced immunosuppression and oxidative stresses. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preclinical and clinical development of YFV 17D-based chimeric vaccines against dengue, West Nile and Japanese encephalitis viruses.

PubMed

Guy, Bruno; Guirakhoo, Farshad; Barban, Veronique; Higgs, Stephen; Monath, Thomas P; Lang, Jean

2010-01-08

Dengue viruses (DENV), West Nile virus (WNV) and Japanese encephalitis virus (JEV) are major global health and growing medical problems. While a live-attenuated vaccine exists since decades against the prototype flavivirus, yellow fever virus (YFV), there is an urgent need for vaccines against dengue or West Nile diseases, and for improved vaccines against Japanese encephalitis. Live-attenuated chimeric viruses were constructed by replacing the genes coding for Premembrane (prM) and Envelope (E) proteins from YFV 17D vaccine strain with those of heterologous flaviviruses (ChimeriVax technology). This technology has been used to produce vaccine candidates for humans, for construction of a horse vaccine for West Nile fever, and as diagnostic reagents for dengue, Japanese encephalitis, West Nile and St. Louis encephalitis infections. This review focuses on human vaccines and their characterization from the early stages of research through to clinical development. Phenotypic and genetic properties and stability were examined, preclinical evaluation through in vitro or animal models, and clinical testing were carried out. Theoretical environmental concerns linked to the live and genetically modified nature of these vaccines have been carefully addressed. Results of the extensive characterizations are in accordance with the immunogenicity and excellent safety profile of the ChimeriVax-based vaccine candidates, and support their development towards large-scale efficacy trials and registration.

Gene expression in the deep biosphere.

PubMed

Orsi, William D; Edgcomb, Virginia P; Christman, Glenn D; Biddle, Jennifer F

2013-07-11

Scientific ocean drilling has revealed a deep biosphere of widespread microbial life in sub-seafloor sediment. Microbial metabolism in the marine subsurface probably has an important role in global biogeochemical cycles, but deep biosphere activities are not well understood. Here we describe and analyse the first sub-seafloor metatranscriptomes from anaerobic Peru Margin sediment up to 159 metres below the sea floor, represented by over 1 billion complementary DNA (cDNA) sequence reads. Anaerobic metabolism of amino acids, carbohydrates and lipids seem to be the dominant metabolic processes, and profiles of dissimilatory sulfite reductase (dsr) transcripts are consistent with pore-water sulphate concentration profiles. Moreover, transcripts involved in cell division increase as a function of microbial cell concentration, indicating that increases in sub-seafloor microbial abundance are a function of cell division across all three domains of life. These data support calculations and models of sub-seafloor microbial metabolism and represent the first holistic picture of deep biosphere activities.

Continentward-dipping detachment fault system and asymmetric rift structure of the Baiyun Sag, northern South China Sea

NASA Astrophysics Data System (ADS)

Zhou, Zhichao; Mei, Lianfu; Liu, Jun; Zheng, Jinyun; Chen, Liang; Hao, Shihao

2018-02-01

The rift architecture and deep crustal structure of the distal margin at the mid-northern margin of the South China Sea have been previously investigated by using deep seismic reflection profiles. However, one fundamental recurring problem in the debate is the extensional fault system and rift structure of the hyperextended rift basins (Baiyun Sag and Liwan Sag) within the distal margin because of the limited amount of seismic data. Based on new 3D seismic survey data and 2D seismic reflection profiles, we observe an array of fault blocks in the Baiyun Sag, which were tilted towards the ocean by extensional faulting. The extensional faults consistently dip towards the continent. Beneath the tilted fault blocks and extensional faults, a low-angle, high-amplitude and continuous reflection has been interpreted as the master detachment surface that controls the extension process. During rifting, the continentward-dipping normal faults evolved in a sequence from south to north, generating the asymmetric rift structure of the Baiyun Sag. The Baiyun Sag is separated from the oceanic domain by a series of structural highs that were uplifted by magmatic activity in response to the continental breakup at 33 Ma and a ridge jump to the south at 26-24 Ma. Therefore, we propose that magmatism played a significant role in the continental extension and final breakup in the South China Sea.

Geological and biological heterogeneity of the Aleutian margin (1965-4822 m)

NASA Astrophysics Data System (ADS)

Rathburn, A. E.; Levin, L. A.; Tryon, M.; Gieskes, J. M.; Martin, J. B.; Pérez, M. E.; Fodrie, F. J.; Neira, C.; Fryer, G. J.; Mendoza, G.; McMillan, P. A.; Kluesner, J.; Adamic, J.; Ziebis, W.

2009-01-01

Geological, biological and biogeochemical characterization of the previously unexplored margin off Unimak Island, Alaska between 1965 and 4822 m water depth was conducted to examine: (1) the geological processes that shaped the margin, (2) the linkages between depth, geomorphology and environmental disturbance in structuring benthic communities of varying size classes and (3) the existence, composition and nutritional sources of methane seep biota on this margin. The study area was mapped and sampled using multibeam sonar, a remotely operated vehicle (ROV) and a towed camera system. Our results provide the first characterization of the Aleutian margin mid and lower slope benthic communities (microbiota, foraminifera, macrofauna and megafauna), recognizing diverse habitats in a variety of settings. Our investigations also revealed that the geologic feature known as the “Ugamak Slide” is not a slide at all, and could not have resulted from a large 1946 earthquake. However, sediment disturbance appears to be a pervasive feature of this margin. We speculate that the deep-sea occurrence of high densities of Elphidium, typically a shallow-water foraminiferan, results from the influence of sediment redeposition from shallower habitats. Strong representation of cumacean, amphipod and tanaid crustaceans among the Unimak macrofauna may also reflect sediment instability. Although some faunal abundances decline with depth, habitat heterogeneity and disturbance generated by canyons and methane seepage appear to influence abundances of biota in ways that supercede any clear depth gradient in organic matter input. Measures of sediment organic matter and pigment content as well as C and N isotopic signatures were highly heterogeneous, although the availability of organic matter and the abundance of microorganisms in the upper sediment (1-5 cm) were positively correlated. We report the first methane seep on the Aleutian slope in the Unimak region (3263-3285 m), comprised of clam bed, pogonophoran field and carbonate habitats. Seep foraminiferal assemblages were dominated by agglutinated taxa, except for habitats above the seafloor on pogonophoran tubes. Numerous infaunal taxa in clam bed and pogonophoran field sediments and deep-sea “reef” cnidarians (e.g., corals and hydroids) residing on rocks near seepage sites exhibited light organic δ 13C signatures indicative of chemosynthetic nutritional sources. The extensive geological, biogeochemical and biological heterogeneity as well as disturbance features observed on the Aleutian slope provide an attractive explanation for the exceptionally high biodiversity characteristic of the world’s continental margins.

The Future of the Deep Space Network: Technology Development for K2-Band Deep Space Communications

NASA Technical Reports Server (NTRS)

Bhanji, Alaudin M.

1999-01-01

Projections indicate that in the future the number of NASA's robotic deep space missions is likely to increase significantly. A launch rate of up to 4-6 launches per year is projected with up to 25 simultaneous missions active [I]. Future high resolution mapping missions to other planetary bodies as well as other experiments are likely to require increased downlink capacity. These future deep space communications requirements will, according to baseline loading analysis, exceed the capacity of NASA's Deep Space Network in its present form. There are essentially two approaches for increasing the channel capacity of the Deep Space Network. Given the near-optimum performance of the network at the two deep space communications bands, S-Band (uplink 2.025-2.120 GHz, downlink 2.2-2.3 GHz), and X-Band (uplink 7.145-7.19 GHz, downlink 8.48.5 GHz), additional improvements bring only marginal return for the investment. Thus the only way to increase channel capacity is simply to construct more antennas, receivers, transmitters and other hardware. This approach is relatively low-risk but involves increasing both the number of assets in the network and operational costs.

Deep Unfolding for Topic Models.

PubMed

Chien, Jen-Tzung; Lee, Chao-Hsi

2018-02-01

Deep unfolding provides an approach to integrate the probabilistic generative models and the deterministic neural networks. Such an approach is benefited by deep representation, easy interpretation, flexible learning and stochastic modeling. This study develops the unsupervised and supervised learning of deep unfolded topic models for document representation and classification. Conventionally, the unsupervised and supervised topic models are inferred via the variational inference algorithm where the model parameters are estimated by maximizing the lower bound of logarithm of marginal likelihood using input documents without and with class labels, respectively. The representation capability or classification accuracy is constrained by the variational lower bound and the tied model parameters across inference procedure. This paper aims to relax these constraints by directly maximizing the end performance criterion and continuously untying the parameters in learning process via deep unfolding inference (DUI). The inference procedure is treated as the layer-wise learning in a deep neural network. The end performance is iteratively improved by using the estimated topic parameters according to the exponentiated updates. Deep learning of topic models is therefore implemented through a back-propagation procedure. Experimental results show the merits of DUI with increasing number of layers compared with variational inference in unsupervised as well as supervised topic models.

Assessment of Undiscovered Oil and Gas Resources of the Nile Delta Basin Province, Eastern Mediterranean

USGS Publications Warehouse

Kirschbaum, Mark A.; Schenk, Christopher J.; Charpentier, Ronald R.; Klett, Timothy R.; Brownfield, Michael E.; Pitman, Janet K.; Cook, Troy A.; Tennyson, Marilyn E.

2010-01-01

The U.S. Geological Survey estimated means of 1.8 billion barrels of recoverable oil, 223 trillion cubic feet of recoverable gas, and 6 billion barrels of natural gas liquids in the Nile Delta Basin Province using a geology-based assessment methodology.

West Nile Virus Documented in Indonesia from Acute Febrile Illness Specimens

PubMed Central

Myint, Khin Saw Aye; Kosasih, Herman; Artika, I. Made; Perkasa, Aditya; Puspita, Mita; Ma'roef, Chairin Nisa; Antonjaya, Ungke; Ledermann, Jeremy P.; Powers, Ann M.; Alisjahbana, Bachti

2014-01-01

We report the presence of West Nile virus in a cryopreserved, dengue-negative serum specimen collected from an acute fever case on Java in 2004–2005. The strain belongs to genotype lineage 2, which has recently been implicated in human outbreaks in Europe. PMID:24420775

Vector competence of the stable fly (Diptera: Muscidae)for West Nile virus.

USDA-ARS?s Scientific Manuscript database

Stable flies, which are notorious pests of cattle and other livestock, were suspected of transmitting West Nile virus (WNV) among American white pelicans at the Medicine Lake Wildlife Refuge in northeastern Montana in 2006-2007. However the ability of stable flies to transmit the virus was unknown. ...

Domestic goose model for West Nile virus vaccine efficiency testing

USDA-ARS?s Scientific Manuscript database

West Nile virus (WNV) is an emergent pathogen in the Americas, first reported in New York during 1999, and has since spread across the United States (USA), Central and South America causing neurological disease in humans, horses and some bird species, including domestic geese. No WNV vaccines are li...

Building climate resilience in the Blue Nile/Abay Highlands: Part II-arole for earth system sciences

USDA-ARS?s Scientific Manuscript database

The Blue Nile (Abay) Highlands of Ethiopia are characterized by significant interannual climate variability, dissected topography and associated local climate contrasts, erosive rains and erodible soils, and intense land pressure due to an increasing population and an economy that is almost entirely...

West Nile Virus Isolation in Human and Mosquitoes, Mexico

PubMed Central

Elizondo-Quiroga, Darwin; Davis, C. Todd; Fernandez-Salas, Ildefonso; Escobar-Lopez, Roman; Olmos, Dolores Velasco; Gastalum, Lourdes Cecilia Soto; Acosta, Magaly Aviles; Elizondo-Quiroga, Armando; Gonzalez-Rojas, Jose I.; Cordero, Juan F. Contreras; Guzman, Hilda; Travassos da Rosa, Amelia; Blitvich, Bradley J.; Barrett, Alan D.T.; Beaty, Barry J.

2005-01-01

West Nile virus has been isolated for the first time in Mexico, from a sick person and from mosquitoes (Culex quinquefasciatus). Partial sequencing and analysis of the 2 isolates indicate that they are genetically similar to other recent isolates from northern Mexico and the western United States. PMID:16229779

Spatially Explicit West Nile Virus Risk Modeling in Santa Clara County, CA

USDA-ARS?s Scientific Manuscript database

A geographic information systems model designed to identify regions of West Nile virus (WNV) transmission risk was tested and calibrated with data collected in Santa Clara County, California. American Crows that died from WNV infection in 2005, provided spatial and temporal ground truth. When the mo...

Spatially explicit West Nile virus risk modeling in Santa Clara County, California

USDA-ARS?s Scientific Manuscript database

A previously created Geographic Information Systems model designed to identify regions of West Nile virus (WNV) transmission risk is tested and calibrated in Santa Clara County, California. American Crows that died from WNV infection in 2005 provide the spatial and temporal ground truth. Model param...

Career Counseling of College Students: An Empirical Guide to Strategies That Work.

ERIC Educational Resources Information Center

Luzzo, Darrell Anthony, Ed.

This book contains 17 papers devoted to the counseling of college students. The following papers are included: "Introduction" (Darrell Anthony Luzzo); "Established Career Theories" (Paul J. Hartung, Spencer G. Niles); "Emerging Career Theories" (Spencer G. Niles, Paul J. Hartung); "Emotional-Social Issues in the…

West Nile virus antibody prevalence in wild mammals, southern Wisconsin

USGS Publications Warehouse

Docherty, D.E.; Samuel, M.D.; Nolden, C.A.; Egstad, Kristina F.; Griffin, K.M.

2006-01-01

Twenty percent prevalence of West Nile virus antibody was found in free-ranging medium-sized Wisconsin mammals. No significant differences were noted in antibody prevalence with regard to sex, age, month of collection, or species. Our results suggest a similar route of infection in these mammals.

West Nile Virus Antibody Prevalence in Wild Mammals, Southern Wisconsin

PubMed Central

Docherty, Douglas E.; Nolden, Cherrie A.; Egstad, Kristina F.; Griffin, Kathryn M.

2006-01-01

Twenty percent prevalence of West Nile virus antibody was found in free-ranging medium-sized Wisconsin mammals. No significant differences were noted in antibody prevalence with regard to sex, age, month of collection, or species. Our results suggest a similar route of infection in these mammals. PMID:17326959

Visualising DNA in Classrooms Using Nile Blue

ERIC Educational Resources Information Center

Milne, Christine; Roche, Scott; McKay, David

2008-01-01

Giving students the opportunity to extract, manipulate and visualise DNA molecules enhances a constructivist approach to learning about modern techniques in biology and biotechnology Visualisation usually requires agarose gel electrophoresis and staining. In this article, we report on an alternative DNA stain, Nile Blue A, that may be used in the…

Nile tilapia and blue tilapia fry production in a subtropical climate

USDA-ARS?s Scientific Manuscript database

The relationship between production in earthen ponds located in a subtropical climate of fry suitable for hormonal sex inversion and degree-days was quantified for Nile tilapia (Oreochromis niloticus; Egypt strain) and blue tilapia (O. aureus). Degree-days were calculated for each trial as the sum o...

Dermatofibrosarcoma protuberans of the vulva: margins assessment and reconstructive options - a report of two cases.

PubMed

Bertolli, Eduardo; Bretchbuhl, Eduard Renè; Camarço, William Ricardo; Campagnari, Mariane; Molina, André Sapata; Baiocchi, Glauco; Macedo, Mariana Petaccia; Pinto, Clovis Antonio; Cunha, Isabela Werneck; Neto, João Pedreira

2014-12-29

Dermatofibrosarcoma Protuberans (DFSP) of the vulva is rare and oncologic surgery with free margins may lead to severe functional damage, requiring multidisciplinary approach regarding resection, margin assessment and reconstruction.Case Report: Two cases of DFSP in vulva were treated in a single institution. A 28-year-old patient with an incisional biopsy in the vulvar region revealing DFSP underwent a partial vulvectomy with clitoris preservation. Pathological studies revealed free margins and reconstructive surgery was performed. This patient is disease free in a 40 months follow up. The other, a 57-year-old patient was also referred after an incomplete resection of a DFSP in the vulvar region. A 1-cm margim resection followed by Complete Circumferential and Peripheral Deep Margin Assessment (CCPDMA) was performed. Although the upper lateral margin was positive, it was possible to perform another wide local excision with preservation of the clitoris and primary closure. DFSP of the vulva requires an accurate evaluation of margins, resections following oncological principles and reconstruction. Although being a very challenging lesion that usually implies difficult surgical management, if treated in a multidisciplinary environment, with surgical oncologists, experienced dermatopathologists and reconstructive surgeons can achieve good results. Even in difficult cases that presents with large lesions and compromising challenging areas, a complete oncologic resection can be performed minimizing functional damage for the patient.

Structure Deformation of the Minjiang and Huya Fault, the Eastern Margin of the Tibetan Plateau Revealed by Deep Seismic Reflection Profiles

NASA Astrophysics Data System (ADS)

Gao, R.; Wang, H.; Li, W.; Li, H.

2014-12-01

The Minshan region, located along the eastern margin of the Tibetan Plateau north of the Sichuan Basin, provides an important natural laboratory in which to study the patterns of deformation and their relationship to mountain building at the margin of the plateau. The Minshan range is bounded by the Minjiang fault to the west and Huya fault to the east. Evidence from the Neotectonics sediments suggests that deformation along the western Min Shan may reflect the surface response to thickening of a weak lower crust at the margin of the Tibetan Plateau (Kirby et al., 2000). In 2014, two deep seismic profiles was carried out across the Minjiang fault (55 km long) and Huya fault (45 km long) respectively, supported by China geological survey project (No.1212011220260) and Crust Probe Project of China (SinoProbe-02-01). The recording of seismic waves from 4 big shots (500kg), 100 middle shots (120 kg) and 400 small shots (36 kg) were employed. The geophones spacing is 50 m. The preliminary stack sections provide us a detailed deformation mechanism of the Minshan region for the first time. The result shows that: (1) The Huya fault section shows different reflection characteristics on the west and east flank. (2) The Moho reflection beneath the Huya fault, which appeared at 12-13 s two-way time, tilts from the east to the west. (3) The Minjiang fault shows as a series of thrust nappe in the upper crust. (4) A strong reflector appears in the middle crust of the Minjiang section at 8-9 s two-way times, and it dips down to the lower crust from west to east.

Overview of the sedimentological processes in the western North Atlantic

NASA Astrophysics Data System (ADS)

Benetti, S.; Weaver, P.; Wilson, P.

2003-04-01

The sedimentary processes operating within the western North Atlantic continental margin include both along-slope sediment transport, which builds sediment drifts and waves, and down-slope processes involving mass wasting. Sedimentation along a large stretch of the margin (north of 32°N) has been heavily influenced by processes that occurred during glacial times (e.g. cutting of canyons and infilling of abyssal plains) when large volumes of sediment were supplied to the shelf edge either by ice grounded on continental shelves or river discharge. The large area of sea floor occupied by depositional basins and abyssal plains testifies to the dominance of turbidity currents. The widespread presence of slide complexes in this region has been related to earthquakes and melting of gas hydrates. South of 32°N, because of the low sediment supply from rivers even during glacial times and the reduced sedimentation due to the erosive effects of the Gulf Stream, few canyon systems and slides are observed and Tertiary sediment cover is thin and irregular. Turbidity currents filled re-entrant basins in the Florida-Bahama platform. Tectonic activity is primarily responsible for the overall morphology and sedimentation pattern along the Caribbean active margin. Along the whole margin, the reworking of bottom sediments by deep-flowing currents seems to be particularly active during interglacials. To some extent this observation must reflect the diminished effect of downslope transport during interglacials, but our data also contribute to the debate over changes in deep water circulation strength on glacial-interglacial timescales. Strong bottom circulation, an open basin system and high sediment supply have led to the construction of large elongate contourite drifts, mantled by smaller scale bedforms. These drifts are mostly seen in regions protected or distant from the masking influence of turbidity currents and sediment mass movements.

Repeated large-scale retreat and advance of Totten Glacier indicated by inland bed erosion.

PubMed

Aitken, A R A; Roberts, J L; van Ommen, T D; Young, D A; Golledge, N R; Greenbaum, J S; Blankenship, D D; Siegert, M J

2016-05-19

Climate variations cause ice sheets to retreat and advance, raising or lowering sea level by metres to decametres. The basic relationship is unambiguous, but the timing, magnitude and sources of sea-level change remain unclear; in particular, the contribution of the East Antarctic Ice Sheet (EAIS) is ill defined, restricting our appreciation of potential future change. Several lines of evidence suggest possible collapse of the Totten Glacier into interior basins during past warm periods, most notably the Pliocene epoch, causing several metres of sea-level rise. However, the structure and long-term evolution of the ice sheet in this region have been understood insufficiently to constrain past ice-sheet extents. Here we show that deep ice-sheet erosion-enough to expose basement rocks-has occurred in two regions: the head of the Totten Glacier, within 150 kilometres of today's grounding line; and deep within the Sabrina Subglacial Basin, 350-550 kilometres from this grounding line. Our results, based on ICECAP aerogeophysical data, demarcate the marginal zones of two distinct quasi-stable EAIS configurations, corresponding to the 'modern-scale' ice sheet (with a marginal zone near the present ice-sheet margin) and the retreated ice sheet (with the marginal zone located far inland). The transitional region of 200-250 kilometres in width is less eroded, suggesting shorter-lived exposure to eroding conditions during repeated retreat-advance events, which are probably driven by ocean-forced instabilities. Representative ice-sheet models indicate that the global sea-level increase resulting from retreat in this sector can be up to 0.9 metres in the modern-scale configuration, and exceeds 2 metres in the retreated configuration.

IODP workshop: developing scientific drilling proposals for the Argentina Passive Volcanic Continental Margin (APVCM) - basin evolution, deep biosphere, hydrates, sediment dynamics and ocean evolution

NASA Astrophysics Data System (ADS)

Flood, Roger D.; Violante, Roberto A.; Gorgas, Thomas; Schwarz, Ernesto; Grützner, Jens; Uenzelmann-Neben, Gabriele; Hernández-Molina, F. Javier; Biddle, Jennifer; St-Onge, Guillaume; Workshop Participants, Apvcm

2017-05-01

The Argentine margin contains important sedimentological, paleontological and chemical records of regional and local tectonic evolution, sea level, climate evolution and ocean circulation since the opening of the South Atlantic in the Late Jurassic-Early Cretaceous as well as the present-day results of post-depositional chemical and biological alteration. Despite its important location, which underlies the exchange of southern- and northern-sourced water masses, the Argentine margin has not been investigated in detail using scientific drilling techniques, perhaps because the margin has the reputation of being erosional. However, a number of papers published since 2009 have reported new high-resolution and/or multichannel seismic surveys, often combined with multi-beam bathymetric data, which show the common occurrence of layered sediments and prominent sediment drifts on the Argentine and adjacent Uruguayan margins. There has also been significant progress in studying the climatic records in surficial and near-surface sediments recovered in sediment cores from the Argentine margin. Encouraged by these recent results, our 3.5-day IODP (International Ocean Discovery Program) workshop in Buenos Aires (8-11 September 2015) focused on opportunities for scientific drilling on the Atlantic margin of Argentina, which lies beneath a key portion of the global ocean conveyor belt of thermohaline circulation. Significant opportunities exist to study the tectonic evolution, paleoceanography and stratigraphy, sedimentology, and biosphere and geochemistry of this margin.

Estimating Curie Point Depth and Heat Flow Map for Northern Red Sea Rift of Egypt and Its Surroundings, from Aeromagnetic Data

NASA Astrophysics Data System (ADS)

Saleh, Salah; Salk, Müjgan; Pamukçu, Oya

2013-05-01

In this study, we aim to map the Curie point depth surface for the northern Red Sea rift region and its surroundings based on the spectral analysis of aeromagnetic data. Spectral analysis technique was used to estimate the boundaries (top and bottom) of the magnetized crust. The Curie point depth (CPD) estimates of the Red Sea rift from 112 overlapping blocks vary from 5 to 20 km. The depths obtained for the bottom of the magnetized crust are assumed to correspond to Curie point depths where the magnetic layer loses its magnetization. Intermediate to deep Curie point depth anomalies (10-16 km) were observed in southern and central Sinai and the Gulf of Suez (intermediate heat flow) due to the uplifted basement rocks. The shallowest CPD of 5 km (associated with very high heat flow, ~235 mW m-2) is located at/around the axial trough of the Red Sea rift region especially at Brothers Island and Conrad Deep due to its association with both the concentration of rifting to the axial depression and the magmatic activity, whereas, beneath the Gulf of Aqaba, three Curie point depth anomalies belonging to three major basins vary from 10 km in the north to about 14 km in the south (with a mean heat flow of about 85 mW m-2). Moreover, low CPD anomalies (high heat flow) were also observed beneath some localities in the northern part of the Gulf of Suez at Hammam Fraun, at Esna city along River Nile, at west Ras Gharib in the eastern desert and at Safaga along the western shore line of the Red Sea rift. These resulted from deviatoric tensional stresses developing in the lithosphere which contribute to its further extension and may be due to the opening of the Gulf of Suez and/or the Red Sea rift. Furthermore, low CPD (with high heat flow anomaly) was observed in the eastern border of the study area, beneath northern Arabia, due to the quasi-vertical low-velocity anomaly which extends into the lower mantle and may be related to volcanism in northern Arabia. Dense microearthquakes seem to occur in areas where the lateral gradients of the CPD are steep (e.g. entrance of the Gulf of Suez and Brothers Island in the Red Sea). These areas may correspond to the boundaries between high and low thermal regions of the crust. Thus, the variations in the microseismic activity may be closely related to thermal structures of the crust. Indeed, shallow cutoff depths of seismicity can also be found in some geothermal areas (e.g. western area of Safaga city along the Red Sea coastal region and at Esna city along the River Nile). These facts indicate that the changes in the thickness of the seismogenic layer strongly depend on temperature. Generally, the shallow Curie point depth indicates that some regions in our study area are promising regions for further geothermal exploration particularly in some localities along the River Nile, Red Sea and Gulf of Suez coastal regions.

Evidence for an evolving oxygen minimum zone in the Eastern Mediterranean during sapropel S1 controlled partly by the increased outflow from the Nile flood

NASA Astrophysics Data System (ADS)

Zirks, Eleen; Goodman-Tchernov, Beverly; Krom, Michael D.

2017-04-01

Understanding the nature and evolution of past Oxygen Minimum Zones (OMZ) are of great interest since they shed light on expanding OMZ's in the modern ocean. Furthermore, as we alter the nutrient fluxes emitted from modern major rivers there are known to major, often undesirable, consequence to the oxygen status in the marine basin both proximal and distal to the river discharge (e.g. Mississippi). Recent Global Climate Model (GCM) of the nature and development of S-1 sapropel in the Eastern Mediterranean (EMS) have suggested a four layer system with a well-ventilated surface water (0-200 m) and intermediate water (200-500 m), a partially ventilated sapropel intermediate water (SIW, 500-1800 m) and long-term stagnant deep water below 1800 m. Our conceptual model is of the partially ventilated SIW flowing from Adriatic/Aegean towards the east and becoming depleted in oxygen as it is increasingly influenced by descending labile organic matter derived directly or indirectly from the Nile flood. Most studies of sapropels in the EMS concentrate on the deep water below 1800 m water depths with only a limited number of samples having been taken from the SIW layer. In this review, we focus on the several stations sampled between 500-1800 m and particularly on stations in the Eastern Aegean and Levantine basins. Data has been obtained from sediment cores (9509, 9501, SL112, PS009PC, SL123, 562MC) in which either benthic foraminifera fauna or redox sensitive trace metals (RSTM) data have been measured. The Shannon-Weaver diversity index and the Oxygen Index have been calculated on the benthic foraminifera fauna. These cores reveal a distinct pattern in onset and offset of sapropel S1 and in the interruption of the sapropel at 8.2 ka BP. The onset of S1 was earlier in the shallower water depths consistent with greater respiration rates from progressively less labile organic matter dropping from the photic zone. There was a clear spatial trend in intensity of the OMZ with benthic foraminifera surviving in SIW throughout S1 offshore Libya (562MC) and close to Crete (SL123) nearer the source of SIW. By contrast the diversity is reduced and in case of 562MC the Oxygen Index reached zero close to the Israeli coast and under the direct influence of the Nile. There was an observed correlation between the V/Al ratio (PS009PC), a redox sensitive trace metal used as an indicator for sub-oxic conditions in the water column and the calculated Oxygen Index as well as diversity on benthic foraminifera (SL112). Our study also shows that the intensity of S1 sapropel was greater in this region between its onset and the 8.2 interruption, than in the period from 8.2 to the end of S1. Indeed, close to Cyprus (9501) sapropel S1 ends at 8.2 ka BP and doesn't have a second sapropelic part.

Earth observations taken during STS-83 mission

NASA Image and Video Library

2016-08-12

STS083-747-026 (4-8 April 1997) --- Aswan Dam and Lake Nasser along the Nile River, Egypt. The Aswan Dam controls the flow of the Nile River forming Lake Nasser. Lake Nasser is reaching relatively high water levels due to the plentiful rains since December 1996 in Kenya, near the headwaters of the Nile river. The light colored areas in the Lake are where the sun is reflecting off the surface of the water. These areas are fairly calm and not disturbed by wind gusts enabling the sunglint to show water current patterns on the surface. The Aswan runway is seen as a dark set of lines west of the Aswan Dam.

Alexander the Great and West Nile virus encephalitis.

PubMed

Marr, John S; Calisher, Charles H

2003-12-01

Alexander the Great died in Babylon in 323 BC. His death at age 32 followed a 2-week febrile illness. Speculated causes of death have included poisoning; assassination, and a number of infectious diseases. One incident, mentioned by Plutarch but not considered by previous investigators, may shed light on the cause of Alexander's death. The incident, which occurred as he entered Babylon, involved a flock of ravens exhibiting unusual behavior and subsequently dying at his feet. The inexplicable behavior of ravens is reminiscent of avian illness and death weeks before the first human cases of West Nile virus infection were identified in the United States. We posit that Alexander may have died of West Nile virus encephalitis.

Alexander the Great and West Nile Virus Encephalitis

PubMed Central

Marr, John S.

2003-01-01

Alexander the Great died in Babylon in 323 BC. His death at age 32 followed a 2-week febrile illness. Speculated causes of death have included poisoning, assassination, and a number of infectious diseases. One incident, mentioned by Plutarch but not considered by previous investigators, may shed light on the cause of Alexander’s death. The incident, which occurred as he entered Babylon, involved a flock of ravens exhibiting unusual behavior and subsequently dying at his feet. The inexplicable behavior of ravens is reminiscent of avian illness and death weeks before the first human cases of West Nile virus infection were identified in the United States. We posit that Alexander may have died of West Nile encephalitis. PMID:14725285

Preliminary potential-field constraints on the geometry of the San Fernando basin, Southern California

USGS Publications Warehouse

Langenheim, V.E.; Griscom, Andrew; Jachens, R.C.; Hildenbrand, T.G.

2000-01-01

Gravity and magnetic data provide new insights on the structural underpinnings of the San Fernando Basin region, which may be important to ground motion models. Gravity data indicate that a deep basin (>5 km) underlies the northern part of the San Fernando Valley; this deep basin is required to explain the lowest gravity values over the Mission Hills thrust fault. Gravity modeling, constrained by well data and density information, shows that the basin may reach a thickness of 8 km, coinciding with the upper termination of the 1994 Northridge earthquake mainshock rupture. The basin is deeper than previous estimates by 2 to 4 km; this estimate is the result of high densities for the gravels of the Pliocene-Pleisocene Saugus Formation. The geometry of the southern margin of the deep basin is not well-constrained by the gravity data, but may dip to the south. Recently acquired seismic data along the LARSE (Los Angeles Regional Seismic Experiment) II profile may provide constraints to determine the location and attitude of the basin edge. Gravity and aeromagnetic models across the eastern margin of the San Fernando Valley indicate that the Verdugo fault may dip to the southwest along its southern extent and therefore have a normal fault geometry whereas it clearly has a thrust fault geometry along its northern strand.

Regional magnetic anomalies, crustal strength, and the location of the northern Cordilleran fold-and-thrust belt

USGS Publications Warehouse

Saltus, R.W.; Hudson, T.L.

2007-01-01

The northern Cordilleran fold-and-thrust belt in Canada and Alaska is at the boundary between the broad continental margin mobile belt and the stable North American craton. The fold-and-thrust belt is marked by several significant changes in geometry: cratonward extensions in the central Yukon Territory and northeastern Alaska are separated by marginward re-entrants. These geometric features of the Cordilleran mobile belt are controlled by relations between lithospheric strength and compressional tectonic forces developed along the continental margin. Regional magnetic anomalies indicate deep thermal and compositional characteristics that contribute to variations in crustal strength. Our detailed analysis of one such anomaly, the North Slope deep magnetic high, helps to explain the geometry of the fold-and-thrust front in northern Alaska. This large magnetic anomaly is inferred to reflect voluminous mafic magmatism in an old (Devonian?) extensional domain. The presence of massive amounts of malic material in the lower crust implies geochemical depletion of the underlying upper mantle, which serves to strengthen the lithosphere against thermal erosion by upper mantle convection. We infer that deep-source magnetic highs are an important indicator of strong lower crust and upper mantle. This stronger lithosphere forms buttresses that play an important role in the structural development of the northern Cordilleran fold-and-thrust belt. ?? 2007 The Geological Society of America.

Distribution of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons and organochlorinated pollutants in deep-sea sediments of the Southern Cretan margin, Eastern Mediterranean Sea: a baseline assessment.

PubMed

Mandalakis, Manolis; Polymenakou, Paraskevi N; Tselepides, Anastasios; Lampadariou, Nikolaos

2014-07-01

Deep sediments from the southern Cretan margin were analyzed to establish baseline levels for various types of organic pollutants before the anticipated intensification of anthropogenic activities. The total concentration of aliphatic hydrocarbons (ΣAH:326-3758ngg(-1), dry weight) was similar to those reported for deep sediments of the western Mediterranean Sea, while considerably lower levels were measured for polycyclic aromatic hydrocarbons (ΣPAH:9-60ngg(-1)). Source-diagnostic ratios suggested that the aliphatic hydrocarbons in sediments were mainly of terrestrial biogenic origin, while polycyclic aromatic hydrocarbons stemmed from the deposition of long-range transported combustion aerosols. Among the organochlorinated compounds analyzed, β-hexachlorocyclohexane (β-HCH:222-7052pgg(-1)), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (p,p'-DDT:37-2236pgg(-1)) and polychlorinated biphenyls (ΣPCB:38-1182pgg(-1)) showed the highest abundance in sediments. The presence of HCHs and PCBs was attributed to historical inputs that have undergone extensive weathering, whereas an ongoing fresh input was suggested for p,p'-DDT. Multiple linear regression analysis revealed that the levels of the various pollutants in sediments were controlled by different factors, but with organic carbon content playing a prominent role in most cases. Copyright © 2014 Elsevier Ltd. All rights reserved.

Reefal petroleum prospects possible in Pakistan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quadri, V.N.; Quadri, S.M.G.J.

1996-03-25

Carbonate buildups including reefs and banks have proven to be prolific hydrocarbon reservoirs in the US, Canada, Mexico, North Africa, Southeast Asia, and the Middle East. Seismic interpretation, particularly of high quality marine data, and geological analyses, including petrographic studies of selected formations, reveal a broad spectrum of possible reefal prospects in formations of different ages in Pakistan. However, the region with good seismic that provides good recognition of possible reefal buildups remains to date devoid of well confirmation. Oil and Gas Development Corp. of Pakistan formed the technical services department in 1976 for a systematic scientific review of allmore » exploration data and basin analysis. In 1985 this department was renamed offshore department, with responsibility for all offshore exploration. This article is based on the department`s work in collaboration with geoscientists from Russia, the US, Norway, and Canada covering the area shown. Four major types of carbonate buildups, easily recognized from seismic interpretation, include: barrier buildups that are linear with relatively deep water on both sides during deposition; pinnacle buildups that are roughly equidimensional and were surrounded by deep water during deposition; shelf margin buildups that are linear with deep water on one side and shallow water on the other; and patch buildups that form in shallow water either in close proximity to shelf margins, or over broad shallow seas.« less

Geology of the Sierra de Fiambala, northwestern Argentina: implications for Early Palaeozoic Andean tectonics

USGS Publications Warehouse

Grissom, G.C.; DeBari, S.M.; Snee, L.W.

1998-01-01

This paper is included in the Special Publication entitled 'The proto- Andean margin of Gondwana', edited by R.J. Pankhurst and C.W. Rapela. Field mapping in conjunction with structural, metamorphic, and geochronological data document the tectono-thermal history of exhumed deep crustal rocks in the Sierra de Fiambala, NW Argentina. The range consists of two structural blocks distinguished by different metasedimentary sequences and different grades of metamorphism. Orthogneiss and paragneiss in the northern structural block may have a Precambrian history. Greenschist- to amphibolite-facies metamorphism, intrusion, and injection magmatization affected all rocks at 540-550 Ma. A subsequent event in the Late Cambrian to Ordovician (c.515 to 470 Ma) involved amphibolite- to granulite-facies metamorphism, mafic intrusion, and deformation, followed by cooling through mid-Palaeozoic time. The emplacement of Carboniferous (325-350 Ma) post-tectonic granites caused reheating and retrogression that was strongest toward the northeast part of the range. The Cambrian, Ordovician, and Carboniferous events in the Sierra de Fiambala were of regional extent as indicated by temporal correlations with events reported for other deep crustal rocks of the northern Sierras Pampeanas. Correlations between periods of intrusion and high-grade metamorphism in the northern Sierras Pampeanas and volcanic-sedimentary events in the adjacent supracrustal exposures confirm that rocks in the northern Sierras Pampeanas formed at deep (10-25 km) structural levels in the early Palaeozoic continental margin of Gondwana.

Cold-seep-like macrofaunal communities in organic- and sulfide-rich sediments of the Congo deep-sea fan

NASA Astrophysics Data System (ADS)

Olu, K.; Decker, C.; Pastor, L.; Caprais, J.-C.; Khripounoff, A.; Morineaux, M.; Ain Baziz, M.; Menot, L.; Rabouille, C.

2017-08-01

Methane-rich fluids arising from organic matter diagenesis in deep sediment layers sustain chemosynthesis-based ecosystems along continental margins. This type of cold seep develops on pockmarks along the Congo margin, where fluids migrate from deep-buried paleo-channels of the Congo River, acting as reservoirs. Similar ecosystems based on shallow methane production occur in the terminal lobes of the present-day Congo deep-sea fan, which is supplied by huge quantities of primarily terrestrial material carried by turbiditic currents along the 800 km channel, and deposited at depths of up to nearly 5000 m. In this paper, we explore the effect of this carbon enrichment of deep-sea sediments on benthic macrofauna, along the prograding lobes fed by the current active channel, and on older lobes receiving less turbiditic inputs. Macrofaunal communities were sampled using either USNEL cores on the channel levees, or ROV blade cores in the chemosynthesis-based habitats patchily distributed in the active lobe complex. The exceptionally high organic content of the surface sediment in the active lobe complex was correlated with unusual densities of macrofauna for this depth, enhanced by a factor 7-8, compared with those of the older, abandoned lobe, whose sediment carbon content is still higher than in Angola Basin at same depth. Macrofaunal communities, dominated by cossurid polychaetes and tanaids were also more closely related to those colonizing low-flow cold seeps than those of typical deep-sea sediment. In reduced sediments, microbial mats and vesicomyid bivalve beds displayed macrofaunal community patterns that were similar to their cold-seep counterparts, with high densities, low diversity and dominance of sulfide-tolerant polychaetes and gastropods in the most sulfidic habitats. In addition, diversity was higher in vesicomyid bivalve beds, which appeared to bio-irrigate the upper sediment layers. High beta-diversity is underscored by the variability of geochemical gradients in vesicomyid assemblages, and by the vesicomyid population characteristics that vary in density, size and composition. By modifying the sediment geochemistry differently according to their morphology and physiology, the different vesicomyid species play an important role structuring macrofauna composition and vertical distribution. Dynamics of turbiditic deposits at a longer temporal scale (thousands of years) and their spatial distribution in the lobe area also resulted in high heterogeneity of the "cold-seep-like communities". Dynamics of chemosynthetic habitats and associated macrofauna in the active lobe area resembled those previously observed at the Regab pockmark along the Congo margin and rapid succession is expected to cope with high physical disturbance by frequent turbiditic events and huge sedimentation rates. Finally, we propose a model of the temporal evolution of these peculiar habitats and communities on longer timescales in response to changes in distributary channels within the lobe complex.

A study of the mutational landscape of pediatric-type follicular lymphoma and pediatric nodal marginal zone lymphoma.

PubMed

Ozawa, Michael G; Bhaduri, Aparna; Chisholm, Karen M; Baker, Steven A; Ma, Lisa; Zehnder, James L; Luna-Fineman, Sandra; Link, Michael P; Merker, Jason D; Arber, Daniel A; Ohgami, Robert S

2016-10-01

Pediatric-type follicular lymphoma and pediatric marginal zone lymphoma are two of the rarest B-cell lymphomas. These lymphomas occur predominantly in the pediatric population and show features distinct from their more common counterparts in adults: adult-type follicular lymphoma and adult-type nodal marginal zone lymphoma. Here we report a detailed whole-exome deep sequencing analysis of a cohort of pediatric-type follicular lymphomas and pediatric marginal zone lymphomas. This analysis revealed a recurrent somatic variant encoding p.Lys66Arg in the transcription factor interferon regulatory factor 8 (IRF8) in 3 of 6 cases (50%) of pediatric-type follicular lymphoma. This specific point mutation was not detected in pediatric marginal zone lymphoma or in adult-type follicular lymphoma. Additional somatic point mutations in pediatric-type follicular lymphoma were observed in genes involved in transcription, intracellular signaling, and cell proliferation. In pediatric marginal zone lymphoma, no recurrent mutation was identified; however, somatic point mutations were observed in genes involved in cellular adhesion, cytokine regulatory elements, and cellular proliferation. A somatic variant in AMOTL1, a recurrently mutated gene in splenic marginal zone lymphoma, was also identified in a case of pediatric marginal zone lymphoma. The overall non-synonymous mutational burden was low in both pediatric-type follicular lymphoma and pediatric marginal zone lymphoma (4.6 mutations per exome). Altogether, these findings support a distinctive genetic basis for pediatric-type follicular lymphoma and pediatric marginal zone lymphoma when compared with adult subtypes and to one another. Moreover, identification of a recurrent point mutation in IRF8 provides insight into a potential driver mutation in the pathogenesis of pediatric-type follicular lymphoma with implications for novel diagnostic or therapeutic strategies.

A study of the mutational landscape of pediatric-type follicular lymphoma and pediatric nodal marginal zone lymphoma

PubMed Central

Ozawa, Michael G; Bhaduri, Aparna; Chisholm, Karen M; Baker, Steven A; Ma, Lisa; Zehnder, James L; Luna-Fineman, Sandra; Link, Michael P; Merker, Jason D; Arber, Daniel A; Ohgami, Robert S

2016-01-01

Pediatric-type follicular lymphoma and pediatric marginal zone lymphoma are two of the rarest B-cell lymphomas. These lymphomas occur predominantly in the pediatric population and show features distinct from their more common counterparts in adults: adult-type follicular lymphoma and adult-type nodal marginal zone lymphoma. Here we report a detailed whole-exome deep sequencing analysis of a cohort of pediatric-type follicular lymphomas and pediatric marginal zone lymphomas. This analysis revealed a recurrent somatic variant encoding p.Lys66Arg in the transcription factor interferon regulatory factor 8 (IRF8) in 3 of 6 cases (50%) of pediatric-type follicular lymphoma. This specific point mutation was not detected in pediatric marginal zone lymphoma or in adult-type follicular lymphoma. Additional somatic point mutations in pediatric-type follicular lymphoma were observed in genes involved in transcription, intracellular signaling, and cell proliferation. In pediatric marginal zone lymphoma, no recurrent mutation was identified; however, somatic point mutations were observed in genes involved in cellular adhesion, cytokine regulatory elements, and cellular proliferation. A somatic variant in AMOTL1, a recurrently mutated gene in splenic marginal zone lymphoma, was also identified in a case of pediatric marginal zone lymphoma. The overall non-synonymous mutational burden was low in both pediatric-type follicular lymphoma and pediatric marginal zone lymphoma (4.6 mutations per exome). Altogether, these findings support a distinctive genetic basis for pediatric-type follicular lymphoma and pediatric marginal zone lymphoma when compared with adult subtypes and to one another. Moreover, identification of a recurrent point mutation in IRF8 provides insight into a potential driver mutation in the pathogenesis of pediatric-type follicular lymphoma with implications for novel diagnostic or therapeutic strategies. PMID:27338637

Geochemical constraints on the provenance and depositional environment of the Messinian sediments, onshore Nile Delta, Egypt: Implications for the late Miocene paleogeography of the Mediterranean

NASA Astrophysics Data System (ADS)

Leila, Mahmoud; Moscariello, Andrea; Šegvić, Branimir

2018-07-01

The Messinian sequence rocks in the Nile Delta present prolific hydrocarbon reservoirs and are, therefore, of great importance from the aspect of petroleum exploration and development strategies. Yet, little is known about their tectonic provenance and depositional setting. This study focuses on the geochemical signatures archived in the Messinian siliciclastic sediments to employ them as a powerful tool to elucidate the basin evolution during the Messinian salinity crisis (MSC). The pre-MSC Qawasim sediments are texturally and compositionally immature. They are enriched in lithic fragments, foraminiferal bioclasts, and rounded heavy minerals suggesting a significant contribution from the pre-existing Cretaceous-Eocene mixed carbonate-siliciclastic rocks bordering the Nile Delta. In contrast, the textural and mineralogical compositions as well as a range of geochemical proxies (e.g., chemical index of alteration and weathering CIA, CIW as well as index of chemical variability ICV and Zr/Sc ratio) are in favor of prolonged weathering and at least second-cycle origin of the MSC Abu Madi sediments. The mutually correspondent elemental ratios (e.g., Al2O3/TiO2, K2O/Na2O, Zr/Hf, Rb/Sr, Cr/Zr, and Cr/Th) and uniform weathering trends are indicatives for a similar provenance of the pre-MSC Qawasim and MSC Abu Madi sediments. Rare earth element (REE) distribution reveals a significant enrichment in LREE, depletion in HREE, relatively high (La/Yb)N (mean > 9), low (Gd/Yb)N (mean < 2) and a pronounced negative Eu anomaly (mean∼0.75) in the studied Messinian facies, characteristics of upper continental sources of mainly felsic to intermediate rock affiliations. Provenance proxy ratios (e.g., Al/Ti, La/Sc, Th/Sc, La/Co and Eu/Eu*) along with the low concentration of transition trace elements (Cr, Ni, Co, Ni) are effectively ruling out the contribution from mafic and ultramafic rocks. The investigated Messinian sedimentary facies have similar passive margin geotectonic setting and their source rocks were originated in a continental collision tectonic setting that lasted from Late Cretaceous to Oligo-Miocene time. This is confirmed by the Nb/Ta, Zr/Sm ratios coupled with the pronounced Nb, Ta, P, Ti anomalies and enrichments in Pb and U relative to primitive mantle typical of subduction zone environment. The petrographical and geochemical results suggest the MSC Abu Madi sediments to have been eroded and recycled from the older pre-MSC Qawasim sediments by gravity-flow processes and fluvial channels prior to redeposition as incised-valley-fills during the late stage of the MSC. The geochemical paleoenvironmental indicators such as C-value, Sr/Cu and Sr/Ba confirm arid-dry climatic conditions during the onset of the MSC consistent with the Mediterranean desiccation. These indicators also depict a transition from freshwater to relatively normal salinity conditions during the late stage of the MSC. Geochemical results presented in this study support the retrogradational depositional infill of the Messinian incised valleys in the Nile Delta, thus confirming an incipient rise in the Mediterranean Sea level prior to the major Zanclean flooding.

Opportunities for woody crop production using treated wastewater in Egypt. II. Irrigation strategies

USDA-ARS?s Scientific Manuscript database

Egypt's share of Nile waters is allocated according to international treaty obligations and is fixed at 55.5 billion cubic meters annually. As a result, Egypt will not be able to meet increasing water demand using freshwater from the Nile and has been developing non-conventional wastewater reuse st...

West Nile virus infection in killer whale, Texas, USA, 2007.

PubMed

St Leger, Judy; Wu, Guang; Anderson, Mark; Dalton, Les; Nilson, Erika; Wang, David

2011-08-01

In 2007, nonsuppurative encephalitis was identified in a killer whale at a Texas, USA, marine park. Panviral DNA microarray of brain tissue suggested West Nile virus (WNV); WNV was confirmed by reverse transcription PCR and sequencing. Immunohistochemistry demonstrated WNV antigen within neurons. WNV should be considered in cases of encephalitis in cetaceans.

West Nile Virus Infection in Commercial Waterfowl Operation, Wisconsin

PubMed Central

Kronenwetter-Koepel, Tamara A.; Vandermause, Mary F.; Reed, Kurt D.

2006-01-01

A West Nile virus (WNV) outbreak occurred at a commercial waterfowl operation in Wisconsin in 2005. Retrospective analysis of dead and live birds was conducted. WNV was detected by PCR in 84.1% of 88 dead birds; neutralizing antibodies were found in 14 of 30 randomly sampled asymptomatic or recovered birds. PMID:17073102

Ovicidal and larvicidal effects of garlic and asafoetida essential oils against West Nile virus vectors

USDA-ARS?s Scientific Manuscript database

We examined the chemical composition of garlic and asafoetida essential oils and their individual and combined toxicity against larvae of two West Nile virus vectors, Culex pipiens pipiens and Cx. restuans. The effect of the two essential oils on egg hatch was also examined. Ten and twelve compounds...

Domestic goose as a model for West Nile virus vaccine efficacy

USDA-ARS?s Scientific Manuscript database

West Nile virus (WNV) is an emergent pathogen in the Americas, first reported in New York during 1999, and has since spread across the United States (USA), Central and South America causing neurological disease in humans, horses and some bird species, including domestic geese. No WNV vaccines are li...

Introductions of West Nile Virus Strains to Mexico

PubMed Central

Deardorff, Eleanor; Estrada-Franco, José G.; Brault, Aaron C.; Navarro-Lopez, Roberto; Campomanes-Cortes, Arturo; Paz-Ramirez, Pedro; Solis-Hernandez, Mario; Ramey, Wanichaya N.; Davis, C. Todd; Beasley, David W.C.; Tesh, Robert B.; Barrett, Alan D.T.

2006-01-01

Complete genome sequencing of 22 West Nile virus isolates suggested 2 independent introductions into Mexico. A previously identified mouse-attenuated glycosylation variant was introduced into southern Mexico through the southeastern United States, while a common US genotype appears to have been introduced incrementally into northern Mexico through the southwestern United States. PMID:16494762

Year-round West Nile virus activity, Gulf Coast region, Texas and Louisiana.

PubMed

Tesh, Robert B; Parsons, Ray; Siirin, Marina; Randle, Yvonne; Sargent, Chris; Guzman, Hilda; Wuithiranyagool, Taweesak; Higgs, Stephen; Vanlandingham, Dana L; Bala, Adil A; Haas, Keith; Zerinque, Brian

2004-09-01

West Nile virus (WNV) was detected in 11 dead birds and two mosquito pools collected in east Texas and southern Louisiana during surveillance studies in the winter of 2003 to 2004. These findings suggest that WNV is active throughout the year in this region of the United States.

West nile virus anti-body surveillance in three Sierra Nevada raptors of conservation concern

Treesearch

J.M. Hull; J.J. Keane; L.A. Tell; H.B. Ernest

2010-01-01

West Nile virus (WNV) infection has caused high levels of mortality in North American hawks and owls. To investigate the extent of infection among raptors of conservation concern in the Sierra Nevada, we tested 62 Northern Goshawks (Accipiter gentilis), 209 Spotted Owls (Strix occidentalis), and 22 Great Gray Owls (...

West Nile Virus Encephalitis in a Barbary Macaque (Macaca sylvanus)

PubMed Central

Barker, Ian K.; Crawshaw, Graham J.; Bertelsen, Mads F.; Drebot, Michael A.; Andonova, Maya

2004-01-01

An aged Barbary ape (Macaca sylvanus) at the Toronto Zoo became infected with naturally acquired West Nile virus (WNV) encephalitis that caused neurologic signs, which, associated with other medical problems, led to euthanasia. The diagnosis was based on immunohistochemical assay of brain lesions, reverse transcriptase–polymerase chain reaction, and virus isolation. PMID:15200866

Efficacy of QCDCR formulated CpG ODN 2007 in Nile tilapia against Streptococcus iniae and identification of upregulated genes

USDA-ARS?s Scientific Manuscript database

The potential of using a QCDCR (quilA:cholesterol:dimethyl dioctadecyl ammonium bromide:carbopol:R1005 glycolipid) formulated CpG oligodeoxynucleotide (ODN), ODN 2007, to confer protection in Nile tilapia against Streptococcus iniae infection was evaluated in this study. At two days post treatment, ...

Outbreak of West Nile virus infection in Greece, 2010.

PubMed

Danis, Kostas; Papa, Anna; Theocharopoulos, George; Dougas, Georgios; Athanasiou, Maria; Detsis, Marios; Baka, Agoritsa; Lytras, Theodoros; Mellou, Kassiani; Bonovas, Stefanos; Panagiotopoulos, Takis

2011-10-01

During 2010, an outbreak of West Nile virus infection occurred in Greece. A total of 197 patients with neuroinvasive disease were reported, of whom 33 (17%) died. Advanced age and a history of heart disease were independently associated with death, emphasizing the need for prevention of this infection in persons with these risk factors.

Dead Crow Reports and Location of Human West Nile Virus Cases, Chicago, 2002

PubMed Central

Jones, Roderick C.; Gibbs, Kevin; Paul, William

2004-01-01

During the summer and fall of 2002, an epidemic (223 cases) and epizootic of West Nile virus infections occurred in Chicago. Retrospective spatial analysis demonstrated that age-adjusted human case rates were three times higher inside geographic areas with high early-season crow deaths than outside these areas. PMID:15200837

Early-season avian deaths from West Nile virus as warnings of human infection

USGS Publications Warehouse

Guptill, S.C.; Julian, K.G.; Campbell, G.L.; Price, S.D.; Marfin, A.A.

2003-01-01

An analysis of 2001 and 2002 West Nile virus (WNV) surveillance data shows that counties that report WNV-infected dead birds early in the transmission season are more likely to report subsequent WNV disease cases in humans than are counties that do not report early WNV-infected dead birds.

Mosquito and West Nile virus surveillance in northeast Montana, U.S.A., 2005-2006

USDA-ARS?s Scientific Manuscript database

Mosquito and West Nile virus surveillance was conducted on a National Wildlife Refuge in northeast Montana, 2005-2006, during which outbreaks of WNV in a colony of American white pelicans (Pelecanus erythrorhynchos Gmelin) resulted in juvenile mortality rates of 30 and 31%. During both years, flood...

Corvidae feather pulp and West Nile virus detection

USGS Publications Warehouse

Docherty, D.E.; Romaine Long, R.; Griffin, Katie M.; Saito, E.K.

2004-01-01

We evaluated cloacal swab, vascular pulp of flight feather, and kidney and spleen pool samples from carcasses of members of the family Corvidae as sources of West Nile virus (WNV). The cloacal swab, kidney and spleen pool, and feather pulp were the source of WNV in 38%, 43%, and 77%, respectively, of the carcasses.

Mosquitoes and the environment in Nile Delta villages with previous rift valley fever activity

USDA-ARS?s Scientific Manuscript database

Egypt is affected by serious human and animal mosquito-borne diseases such as Rift Valley fever (RVF). We investigated how potential RVF virus mosquito vector populations are affected by environmental conditions in the Nile Delta region of Egypt by collecting mosquitoes and environmental data from t...

Reduced West Nile Virus Transmission Around Communal Roosts of Great-Tailed Grackle (Quiscalus mexicanus).

PubMed

Komar, Nicholas; Colborn, James M; Horiuchi, Kalanthe; Delorey, Mark; Biggerstaff, Brad; Damian, Dan; Smith, Kirk; Townsend, John

2015-03-01

West Nile virus has caused several outbreaks among humans in the Phoenix metropolitan area (Arizona, southwest USA) within the last decade. Recent ecologic studies have implicated Culex quinquefasciatus and Culex tarsalis as the mosquito vectors and identified three abundant passerine birds-great-tailed grackle (Quiscalus mexicanus), house sparrow (Passer domesticus), and house finch (Haemorhous mexicanus)-as key amplifiers among vertebrates. Nocturnal congregations of certain species have been suggested as critical for late summer West Nile virus amplification. We evaluated the hypothesis that house sparrow (P. domesticus) and/or great-tailed grackle (Q. mexicanus) communal roost sites (n = 22 and n = 5, respectively) in a primarily suburban environment were spatially associated with West Nile virus transmission indices during the 2010 outbreak of human neurological disease in metropolitan Phoenix. Spatial associations between human case residences and communal roosts were non-significant for house sparrows, and were negative for great-tailed grackle. Several theories that explain these observations are discussed, including the possibility that grackle communal roosts are protective.

Earth observations taken during STS-102 flight

NASA Image and Video Library

2001-03-18

STS102-303-017 (8-21 March 2001)--- The STS-102 crew members used a 35mm camera on the flight deck of the Space Shuttle Discovery to record this image of the Aswan High Dam. The structure was completed in 1970 and is one of the largest earthen embankment dams in the world. It is 364 feet (111 meters) tall, 12,565 feet (3,830 meters) long and nearly 3,281 feet (1,000 meters) wide. When it was built the new reservoir required relocation of nearly 100,000 residents and some archaeological sites. Although the reservoir has benefited Egypt by providing power and controlling floods, according to NASA scientists, it has also had detrimental effects on the Nile system. Before the dam, an estimated 110 million tons of silt was deposited by the annual flood of the Nile, enriching agricultural lands and maintaining the land of the Nile delta. Now this sediment is trapped behind the dam, requiring artificial fertilization of agricultural lands and leading to erosion and saltwater intrusion where the Nile river meets the Mediterranean Sea.

An ensemble and single-molecule fluorescence microscopy investigation of phase-separated monolayer films stained with Nile Red.

PubMed

Lu, Yin; Porterfield, Robyn; Thunder, Terri; Paige, Matthew F

2011-01-01

Phase-separated Langmuir-Blodgett monolayer films prepared from mixtures of arachidic acid (C19H39COOH) and perfluorotetradecanoic acid (C13F27COOH) were stained via spin-casting with the polarity sensitive phenoxazine dye Nile Red, and characterized using a combination of ensemble and single-molecule fluorescence microscopy measurements. Ensemble fluorescence microscopy and spectromicroscopy showed that Nile Red preferentially associated with the hydrogenated domains of the phase-separated films, and was strongly fluorescent in these areas of the film. These measurements, in conjunction with single-molecule fluorescence imaging experiments, also indicated that a small sub-population of dye molecules localizes on the perfluorinated regions of the sample, but that this sub-population is spectroscopically indistinguishable from that associated with the hydrogenated domains. The relative importance of selective dye adsorption and local polarity sensitivity of Nile Red for staining applications in phase-separated LB films as well as in cellular environments is discussed in context of the experimental results. Copyright © 2010 Elsevier B.V. All rights reserved.

Inhibitors of Dengue virus and West Nile virus proteases based on the aminobenzamide scaffold.

PubMed

Aravapalli, Sridhar; Lai, Huiguo; Teramoto, Tadahisa; Alliston, Kevin R; Lushington, Gerald H; Ferguson, Eron L; Padmanabhan, R; Groutas, William C

2012-07-01

Dengue and West Nile viruses (WNV) are mosquito-borne members of flaviviruses that cause significant morbidity and mortality. There is no approved vaccine or antiviral drugs for human use to date. In this study, a series of functionalized meta and para aminobenzamide derivatives were synthesized and subsequently screened in vitro against Dengue virus and West Nile virus proteases. Four active compounds were identified which showed comparable activity toward the two proteases and shared in common a meta or para(phenoxy)phenyl group. The inhibition constants (K(i)) for the most potent compound 7n against Dengue and West Nile virus proteases were 8.77 and 5.55 μM, respectively. The kinetics data support a competitive mode of inhibition of both proteases by compound 7n. This conclusion is further supported by molecular modeling. This study reveals a new chemical scaffold which is amenable to further optimization to yield potent inhibitors of the viral proteases via the combined utilization of iterative medicinal chemistry/structure-activity relationship studies and in vitro screening. Copyright © 2012 Elsevier Ltd. All rights reserved.

Opsoclonus myoclonus ataxia associated with West Nile virus infection: A dramatic presentation with benign prognosis?

PubMed

Zaltzman, Roy; Klein, Colin; Gordon, Carlos R

2017-05-15

Opsoclonus myoclonus and ataxia is a combination of severe neurological signs associated with several pathologic agents and conditions. Only few cases of opsoclonus have been related to West Nile virus infection. We report on a 61-year-old woman and on a 55-year-old man who had history of recent fever, who were hospitalized because of acute severe truncal ataxia, opsoclonus and tremor with minimal myoclonic jerks. A through work-up revealed the presence of both IgM and IgG antibodies against West Nile virus both in the serum and Cerebrospinal Fluid and excluded other causes known to be associated with this combination of neurological signs. The first case was treated with corticosteroids, followed by significant improvement, and the second recovered spontaneously. The acute combination of opsoclonus, severe truncal ataxia and tremor with a history of recent fever requires, during the relevant season and in the relevant geographic area, a search for a recent infection with West Nile virus. Though initially suffering from a devastating sickness, our patients eventually recovered. Copyright © 2017 Elsevier B.V. All rights reserved.

From source to sink: Exploring the Quaternary history of the Nile

NASA Astrophysics Data System (ADS)

Woodward, J. C.; Williams, M. A. J.; Garzanti, E.; Macklin, M. G.; Marriner, N.

2015-12-01

Nearly two thousand five hundred years have elapsed since the Greek historian Herodotus (ca. 485-425 BC) posed a number of fundamental questions about the source, age, and flood regime of the River Nile. Herodotus travelled widely in Egypt in around 450 BC - mainly in the Delta and Lower Egypt, but he may have journeyed as far upstream as Aswan and the First Cataract. A keen observer of nature, with a questioning intellect, Herodotus very quickly discerned that the dark alluvial soils of Egypt were very different from the desert soils of Syria and Libya, and inferred that they were derived from the Ethiopian headwaters of the Nile. Herodotus was the first to recognize that Egyptian civilization was, as he put it, ;the gift of the river; (Griffiths, 1966) since he understood that, without the regular and reliable hundred days of flooding during the summer months, and the annual deposition of silts along the floodplains, agriculture would not have been possible on any significant scale under the desert climate of the Nile Valley.

Actin filaments participate in West Nile (Sarafend) virus maturation process.

PubMed

Chu, J J H; Choo, B G H; Lee, J W M; Ng, M L

2003-11-01

West Nile (Sarafend) virus has previously been shown to egress by budding at the plasma membrane of infected cells, but relatively little is known about the mechanism involved in this mode of release. During the course of this study, it was discovered that actin filaments take part in the virus maturation process. Using dual-labeled immunofluorescence and immunoelectron microscopy at late infection (10 hr p.i.), co-localization of viral structural (envelope and capsid) proteins with actin filaments was confirmed. The virus structural proteins were also immunoprecipitated with anti-actin antibody, further demonstrating the strong association between the two components. Perturbation of actin filaments by cytochalasin B strongly inhibited the release of West Nile virus (approximately 10,000-fold inhibition) when compared with the untreated cells. Infectious virus particles were recovered after the removal of cytochalasin B. Further confirmation was obtained when nucleocapsid particles were found associated with disrupted actin filaments at the periphery of cytochalasin B-treated cells. Together, these results showed that actin filaments do indeed have a key role in the release of West Nile (Sarafend) virions. Copyright 2003 Wiley-Liss, Inc.

Preface

NASA Astrophysics Data System (ADS)

Mohriak, Webster; Talwani, Manik

In compiling this volume, we have aimed to develop and enhance our current understanding of the structural evolution and sedimentation processes along divergent continental margins. To counteract the unfortunate situation of a lack of modem seismic and potential fields data on circum-Atlantic passive margins in the literature, we have linked new data from oil companies with that of research institutions. To update the data offered in most volumes used as reference works for the study of continental margins, now upwards of 20 years old, and to remedy the dispersal of important, more recent contributions in specialized journals, we present a current synthesis of materials in one volume focused on the deeper geology of the sedimentary basins along continental margins. In the early 1990s, as oil companies and other institutions developed tools to probe deeper into the architecture of passive margin sedimentary basins, a great amount of data based on regional deep seismic profiles evolved rapidly from its specialized niche as geophysical interpretation of the Earth's interior to widespread use by those same companies and institutions. At the same time, these findings demonstrated that some breakthroughs in data acquisition, processing and interpretation initially achieved by research institutions could almost instantaneously be globalized throughout different research groups, thereby influencing the thinking of geoscientists worldwide.

Gravity Data from the Teboursouk Area ("Diapirs Zone", Northern Tunisia): Characterization of Deep Structures and Updated Tectonic Pattern

NASA Astrophysics Data System (ADS)

Hachani, Fatma; Balti, Hadhemi; Kadri, Ali; Gasmi, Mohamed

2016-04-01

Located between eastern segments of the Atlas and Tell-Rif oro-genic belts, the "Dome zone" of northern Tunisia is characterized by the juxtaposition of various structures that mainly controlled the long geody-namic history of this part of the south-Tethyan Margin. To better understand the organization and deep extension of these structures, gravity data from the Teboursouk key area are proposed. These data include the plotting of Bouguer anomaly map and related parameters such as vertical and horizontal gradients, upward continuation and Euler solution. Compared to geological and structural maps available, they allow the identification of new deep structures and greater precision regarding the characteristics and organization of known ones; consequently, an updated structural pattern is proposed.

Analysis of Low-Biomass Microbial Communities in the Deep Biosphere.

PubMed

Morono, Y; Inagaki, F

2016-01-01

Over the past few decades, the subseafloor biosphere has been explored by scientific ocean drilling to depths of about 2.5km below the seafloor. Although organic-rich anaerobic sedimentary habitats in the ocean margins harbor large numbers of microbial cells, microbial populations in ultraoligotrophic aerobic sedimentary habitats in the open ocean gyres are several orders of magnitude less abundant. Despite advances in cultivation-independent molecular ecological techniques, exploring the low-biomass environment remains technologically challenging, especially in the deep subseafloor biosphere. Reviewing the historical background of deep-biosphere analytical methods, the importance of obtaining clean samples and tracing contamination, as well as methods for detecting microbial life, technological aspects of molecular microbiology, and detecting subseafloor metabolic activity will be discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Deepening Ecological Relationality through Critical Onto-Epistemological Inquiry: Where Transformative Learning Meets Sustainable Science

ERIC Educational Resources Information Center

Williams, Lewis

2013-01-01

Indigenous worldviews remain at the margins of education, science, and sustainability efforts. The emergence of sustainable science holds promise as a means of advancing deep sustainability and recentering Indigenous knowledge. Transformative learning's engagement with sustainable science has the potential to play an integral role in this…

Disrupting the Culture of Silence: Confronting Gender Inequality and Making Change in Higher Education

ERIC Educational Resources Information Center

De Welde, Kristine, Ed.; Stepnick, Andi, Ed.

2014-01-01

Despite tremendous progress toward gender equality and equity in institutions of higher education, deep patterns of discrimination against women in the academy persist. From the "chilly climate" to the "old boys' club," women academics must navigate structures and cultures that continue to marginalize, penalize, and undermine…

Evapotranspiration in the Nile Basin: Identifying dynamics and drivers, 2002–2011

USGS Publications Warehouse

Alemu, Henok; Kaptue, Armel T.; Senay, Gabriel; Wimberly, Michael C.; Henebry, Geoffrey M.

2015-01-01

Analysis of the relationship between evapotranspiration (ET) and its natural and anthropogenic drivers is critical in water-limited basins such as the Nile. The spatiotemporal relationships of ET with rainfall and vegetation dynamics in the Nile Basin during 2002–2011 were analyzed using satellite-derived data. Non-parametric statistics were used to quantify ET-rainfall interactions and trends across land cover types and subbasins. We found that 65% of the study area (2.5 million km2) showed significant (p < 0.05) positive correlations between monthly ET and rainfall, whereas 7% showed significant negative correlations. As expected, positive ET-rainfall correlations were observed over natural vegetation, mixed croplands/natural vegetation, and croplands, with a few subbasin-specific exceptions. In particular, irrigated croplands, wetlands and some forests exhibited negative correlations. Trend tests revealed spatial clusters of statistically significant trends in ET (6% of study area was negative; 12% positive), vegetation greenness (24% negative; 12% positive) and rainfall (11% negative; 1% positive) during 2002–2011. The Nile Delta, Ethiopian highlands and central Uganda regions showed decline in ET while central parts of Sudan, South Sudan, southwestern Ethiopia and northeastern Uganda showed increases. Except for a decline in ET in central Uganda, the detected changes in ET (both positive and negative) were not associated with corresponding changes in rainfall. Detected declines in ET in the Nile delta and Ethiopian highlands were found to be attributable to anthropogenic land degradation, while the ET decline in central Uganda is likely caused by rainfall reduction.

Water balance dynamics in the Nile Basin

USGS Publications Warehouse

Senay, Gabriel B.; Asante, Kwabena; Artan, Guleid A.

2009-01-01

Understanding the temporal and spatial dynamics of key water balance components of the Nile River will provide important information for the management of its water resources. This study used satellite-derived rainfall and other key weather variables derived from the Global Data Assimilation System to estimate and map the distribution of rainfall, actual evapotranspiration (ETa), and runoff. Daily water balance components were modelled in a grid-cell environment at 0·1 degree (∼10 km) spatial resolution for 7 years from 2001 through 2007. Annual maps of the key water balance components and derived variables such as runoff and ETa as a percent of rainfall were produced. Generally, the spatial patterns of rainfall and ETa indicate high values in the upstream watersheds (Uganda, southern Sudan, and southwestern Ethiopia) and low values in the downstream watersheds. However, runoff as a percent of rainfall is much higher in the Ethiopian highlands around the Blue Nile subwatershed. The analysis also showed the possible impact of land degradation in the Ethiopian highlands in reducing ETa magnitudes despite the availability of sufficient rainfall. Although the model estimates require field validation for the different subwatersheds, the runoff volume estimate for the Blue Nile subwatershed is within 7·0% of a figure reported from an earlier study. Further research is required for a thorough validation of the results and their integration with ecohydrologic models for better management of water and land resources in the various Nile Basin ecosystems.

Single cell genomic study of Dehalococcoidites in deep sea sediments of Peru Margin 1230

NASA Astrophysics Data System (ADS)

Kaster, A.; Meyer-Blackwell, K.; Spormann, A. M.

2013-12-01

Dehalogenating Chloroflexi, such as Dehalococcoidites Dhc were originally discovered as the key microorganisms mediating reductive dehalogenation of the prevalent groundwater contaminants tetrachloroethene and trichloroethene. Molecular and genomic studies on their key enzymes for energy conservation, reductive dehalogenases rdh, have provided evidence for ubiquitous horizontal gene transfer. A pioneering study by Futagami et al. discovered novel putative rdh phylotypes in sediments from the Pacific, revealing an unknown and surprising abundance of rdh genes in pristine habitats. The frequent detection of Dhc-related 16S rRNA genes from these environments implied the occurrence of dissimilatory dehalorespiration in marine subsurface sediments, however, pristine Dhc could never be linked to this activity. Despite being ubiquitous in those environments, metabolic life style or ecological function of Dhc in the absence of anthropogenic contaminants is still completely unknown. We therefore analyzed a non-contaminated deep sea sediment sample of the Peru Margin 1230 site by a single cell genomic (SGC) approach. We present for the first time data on three single Dhc cells, helping to elucidate their role in the poorly understood oligotrophic marine sub-surface environment.

Fertility and Childlessness in the United States.

PubMed

Baudin, Thomas; de la Croix, David

2015-06-01

We develop a theory of fertility, distinguishing its intensive margin from its extensive margin. The deep parameters are identified using facts from the 1990 US Census: (i) fertility of mothers decreases with education; (ii) childlessness exhibits a U-shaped relationship with education; (iii) the relationship between marriage rates and education is hump-shaped for women and increasing for men. We estimate that 2.5 percent of women were childless because of poverty and 8.1 percent because of high opportunity cost of childrearing. Over time, historical trends in total factor productivity and in education led to a U-shaped response in childlessness rates while fertility of mothers decreased.

West Nile virus among blood donors in the United States, 2003 and 2004.

PubMed

Stramer, Susan L; Fang, Chyang T; Foster, Gregory A; Wagner, Annette G; Brodsky, Jaye P; Dodd, Roger Y

2005-08-04

West Nile virus first appeared in the United States in 1999 and has since spread throughout the contiguous states, resulting in thousands of cases of disease. By 2002, it was clear that the virus could be transmitted by blood transfusion, and by the middle of 2003, essentially all blood donations were being tested for West Nile virus RNA with the use of investigational nucleic acid amplification tests; testing was performed on individual samples or on "minipools" of up to 16 donations. We analyzed data from the West Nile virus testing program of the American Red Cross for 2003 and 2004 to identify geographic and temporal trends. In areas with a high incidence of infection, individual donations were tested to increase the sensitivity of testing. Donors with reactive results participated in follow-up studies to confirm the original reactivity and to assess the natural history of infection. Routine testing in 2003 and 2004 identified 540 donations that were positive for West Nile virus RNA, of which 362 (67 percent) were IgM-antibody-negative and most likely infectious. Of the 540 positive donations, 148 (27 percent) were detectable only by testing of individual donations, but only 15 of the 148 (10 percent) were negative for IgM antibody. The overall frequencies of RNA-positive donations during the epidemic periods were 1.49 per 10,000 donations in 2003 and 0.44 per 10,000 in 2004. In 2004, 52 percent of the positive donations were from donors in four counties in southern California. Rapid implementation of a nucleic acid amplification test led to the prospective identification of 519 donors who were positive for West Nile virus RNA and the removal of more than 1000 potentially infectious related components from the blood supply of the Red Cross. No cases of transfusion-transmitted infection were confirmed among recipients of the tested blood. Copyright 2005 Massachusetts Medical Society.

Recharge sources and geochemical evolution of groundwater in the Quaternary aquifer at Atfih area, the northeastern Nile Valley, Egypt

NASA Astrophysics Data System (ADS)

El-Sayed, Salah Abdelwahab; Morsy, Samah M.; Zakaria, Khalid M.

2018-06-01

This study addresses the topic of recharge sources and evolution of groundwater in the Atfih area situated in the northeastern part of the Nile Valley, Egypt. Inventory of water wells and collection of groundwater and surface water samples have been achieved. Water samples are analyzed for major ions according to the American Society for Testing and Materials and for the environmental isotopes analysis (oxygen-18 and deuterium) by using a Triple Liquid Isotopic Water Analyzer (Los Gatos). The groundwater is available from the Quaternary aquifer formed mainly of graded sand and gravel interbedded with clay lenses. The hydrogeologic, hydrogeochemical and isotopic investigations indicate the hydrodynamic nature of the aquifer, where different flow paths, recharge sources and evolution mechanisms are distinguished. The directions of groundwater flow are from E, W and S directions suggesting the contribution from Nile River, the Eocene aquifer and the Nile basin, respectively. The groundwater altitudes range from 13 m (MSL) to 44 m (MSL). The hydraulic gradient varies between 0.025 and 0.0015. The groundwater is alkaline (pH > 7) and has salinity ranging from fresh to brackish water (TDS between 528 mg/l and 6070 mg/l). The observed wide range in the ionic composition and water types reflects the effect of different environmental and geological conditions through which the water has flowed. The isotopic compositions of groundwater samples vary between -14.13‰ and +23.56 for δD and between - 2.91‰ and +3.10 for δ18O. The isotopic data indicates that the Quaternary aquifer receive recharge from different sources including the Recent Nile water, surplus irrigation water, old Nile water before the construction of Aswan High Dam, surface runoff of local rains and Eocene aquifer. Evaporation, water rock interaction and mixing between different types of waters are the main processes in the groundwater evolution. Major suggestions are presented to develop the aquifer productivity and to mitigate the deterioration of groundwater quality.

Ocean-color remote sensing of the Nile delta shelf and SE Levantine basin and possible linkage to some mesoscale circulation features and Nile river run-off

NASA Astrophysics Data System (ADS)

Moufaddal, Wahid; Lavender, Samantha

To date, and despite the passage of more than 30 years since the launch of the first satellite based ocean-color sensor, no systematic study of the variability of chlorophyll in the Egyptian Mediterranean coast off the Nile delta has been undertaken using this kind of data. Meantime, available in-situ measurements on chlorophyll and other nutrient parameters along this coast are indeed very modest and scarce. The lack of data has in turn created a large gap in our knowledge on the biogeochemical characteristics of the coastal water and impacts of the Aswan High Dam and other land-use changes on the marine ecosystems and nutrient budget in the Nile delta shelf and the SE Mediterranean. The present study aims to fill part of this gap through application of ocean-color remote sensing and satellite retrieval of phytoplankton chlorophyll. For this purpose a 10-year (1997-2006) monthly satellite dataset from ESA Globcolour project (an ESA Data User Element project: http://www.globcolour.info) was retrieved and subjected to time-series analysis. Results of this analysis revealed that the oceanic and coastal parts off the Nile delta coast and SE Mediterranean manifest from time to time some of the most interesting and dynamical marine features including meso-scale gyres, coastal filaments, localized algal blooms and higher concentration of phytoplankton chlorophyll. These features together with certain physical pro-cesses and surface run-off from Nile mouthes and other land-based sources were found to exert pronounced effects on the nutrient supply and quality of the coastal and oceanic surface waters in this region. Results reveled also that there has been a general upward trend in concentration of surface chlorophyll during the 10-year period from 1997 to 2006 with a coincident rise of the coastal fisheries implying that improvement of nutrient supply is most likely responsible for this rise. Results confirmed also shift of the Nile phytoplankton bloom in space and time after construc-tion of the Aswan High Dam and other subsequent anthropogenic activities Conclusions and results achieved by this study show the importance of ocean-color satellite data for monitoring of biogeochemical impacts of land-use changes on coastal ecosystems and the role which it can play in assessment of the marine productivity and state of the marine fisheries.

The ancient Egyptian civilization: maximum and minimum in coincidence with solar activity

NASA Astrophysics Data System (ADS)

Shaltout, M.

It is proved from the last 22 years observations of the total solar irradiance (TSI) from space by artificial satellites, that TSI shows negative correlation with the solar activity (sunspots, flares, and 10.7cm Radio emissions) from day to day, but shows positive correlations with the same activity from year to year (on the base of the annual average for each of them). Also, the solar constant, which estimated fromth ground stations for beam solar radiations observations during the 20 century indicate coincidence with the phases of the 11- year cycles. It is known from sunspot observations (250 years) , and from C14 analysis, that there are another long-term cycles for the solar activity larger than 11-year cycle. The variability of the total solar irradiance affecting on the climate, and the Nile flooding, where there is a periodicities in the Nile flooding similar to that of solar activity, from the analysis of about 1300 years of the Nile level observations atth Cairo. The secular variations of the Nile levels, regularly measured from the 7 toth 15 century A.D., clearly correlate with the solar variations, which suggests evidence for solar influence on the climatic changes in the East African tropics The civilization of the ancient Egyptian was highly correlated with the Nile flooding , where the river Nile was and still yet, the source of the life in the Valley and Delta inside high dry desert area. The study depends on long -time historical data for Carbon 14 (more than five thousands years), and chronical scanning for all the elements of the ancient Egyptian civilization starting from the firs t dynasty to the twenty six dynasty. The result shows coincidence between the ancient Egyptian civilization and solar activity. For example, the period of pyramids building, which is one of the Brilliant periods, is corresponding to maximum solar activity, where the periods of occupation of Egypt by Foreign Peoples corresponding to minimum solar activity. The decline of the Kingdoms in ancient Egypt and occurrence of the intermediate periods are generally explained by very low Nile floods and prolonged droughts followed by severe famines and the destruction of the political structure. The study declear the role of solar activity on the climatic change, and the humankind history.

Use of Persistent Scatterer Interferometry to Assess Land Deformation in the Nile Delta and its Controlling Factors

NASA Astrophysics Data System (ADS)

Gebremichael, E.; Sultan, M.; Becker, R.; Emil, M.; Ahmed, M.; Chouinard, K.

2015-12-01

We applied Persistent scatterer interferometry (PSInSAR) to assess land deformation (subsidence and uplift) across the entire Nile delta and its surroundings and to identify possible causes of the observed deformation. For the purpose of the present study, 100 Envisat Advanced Synthetic Aperture Radar (ASAR; level 0) scenes that were acquired along four tracks and covering a time span of seven years (2004 to 2010) were used. The scenes extend from the Mediterranean coast in the north to Cairo city in the south. These scenes were focused using Repeat Orbit Interferometry PACkage (ROI_PAC) software and the subsequent PSI processing was done using the Stanford Method for Persistent Scatterers (StaMPS) method. A low coherence threshold (0.2) was used to decrease the impact of vegetation-related poor coherence and decorrelation of the scenes over the investigated time span. Subsidence was observed over: (1) the Demietta Nile River branch (3 to 14 mm/yr) where it intersects the Mediterranean coastline, (2) thick (~ 40 m) Holocene sediments in lake Manzala (up to 9 mm/yr), (3) reclaimed desert areas (west of Nile Delta; up to 12 mm/yr) of high groundwater extraction, (4) along parts of a previously proposed flexure line (up to 10 mm/yr), and (5) along the eastern sections of the Mediterranean coastline (up to 15.7 mm/yr). The city of Alexandria (underlain by carbonate platform) and the terminus of the Rosetta branch of the Nile River seem to experience almost no ground movement (mean subsidence of 0.28 mm/yr and 0.74 mm/yr respectively) while the cities of Ras Elbar and Port Said (underlain by thick Holocene sediment) exhibit the highest subsidence values (up to 14 mm/yr and 8.5 mm/yr respectively). The city of Cairo has also experienced subsidence in limited areas of up to 7.8 mm/yr. High spatial correlation was also observed between the subsiding areas and the Abu Madi incised valley; the largest gas field in the Nile Delta. Most of the area undergoing subsidence in the Nile Delta is related to sediment compaction and/or groundwater extraction, with other factors such as gas extraction and tectonic drivers correlating with smaller areas.

Assessing and managing water scarcity within the Nile River Transboundary Basin

NASA Astrophysics Data System (ADS)

Butts, M. B.; Wendi, D.; Jessen, O. Z.; Riegels, N. D.

2012-04-01

The Nile Basin is the main source of water in the North Eastern Region of Africa and is perhaps one of the most critical river basins in Africa as the riparian countries constitute 40% of the population on the continent but only 10% of the area. This resource is under considerable stress with rising levels of water scarcity, high population growth, watershed degradation, and loss of environmental services. The potential impacts of climate change may significantly exacerbate this situation as the water resources in the Nile Basin are critically sensitive to climate change (Conway, Hanson, Doherty, & Persechino, 2007). The motivation for this study is an assessment of climate change impacts and adaptation potential for floods and droughts within the UNEP project "Adapting to climate change induced water stress in the Nile River Basin", supported by SIDA. This project is being carried out as collaboration between DHI, the UK Met Office, and the Nile Basin Initiative (NBI). The Nile Basin exhibits highly diverse climatological and hydrological characteristics. Thus climate change impacts and adaptive capacity must be addressed at both regional and sub-basin scales. While the main focus of the project is the regional scale, sub-basin scale modelling is required to reflect variability within the basin. One of the major challenges in addressing this variability is the scarcity of data. This paper presents an initial screening modelling study of the water balance of the Nile Basin along with estimates of expected future impacts of climate change on the water balance. This initial study is focussed on the Ethiopian Highlands and the Lake Victoria regions, where the impact of climate change on rainfall is important. A robust sub-basin based monthly water balance model is developed and applied to selected sub-basins. The models were developed and calibrated using publicly available data. One of the major challenges in addressing this variability within the basin is the scarcity of spatial data and the results for the Kagera sub-basin show that it is important to represent the spatial distribution of the hydro-geographic characteristics such as rainfall, soil type, etc., in order to develop a reasonable representation of the water balance. These initial results show that the changes in the water balance and flow regime under climate change exhibit large uncertainty. From an examination the flow duration curves, however, there seems to be a consensus, based on an ensemble of climate projections, that flows will increase slightly the short term (2011-2030) and decrease significantly in the long term 2080-2099. The large uncertainties together with the natural variability in the Nile suggest that there is a strong need to maximise adaptive capacity with the region.

The Nile floodplain, hydroclimatic variability, and its relation with cultural dynamics in ancient Thebes (Luxor, Egypt)

NASA Astrophysics Data System (ADS)

Toonen, Willem H. J.; Graham, Angus; Pennington, Ben; Hunter, Morag; Strutt, Kris; Barker, Dominic; Masson, Aurelia; Emery, Virginia

2016-04-01

The western bank of the river Nile in the Luxor region (Egypt) separates New Kingdom divine temple complexes in the central axis of the river valley from contemporaneous sites on the desert edge and limestone plateau. The intermediate Nile floodplain features relatively few known archaeological sites, but played an important role in the ancient ritual landscape by connecting the focal region of the living (floodplain) with that of the dead (desert). All Royal Funerary Temple Complexes of the New Kingdom period (1539-1077 BCE), which played a central role in the cosmogonical landscape, are positioned within a confined 3.5 km long strip of land on the western edge of the present floodplain. This preferential location, together with contemporary textual sources and tomb scenes suggesting the nearby presence of canals, have led to the hypothesis that natural and human-made waterways may have once connected the main channel of the Nile with the desert edge. Until the present research took place, no detailed study of pre-existing channel networks existed in the region, leaving a gap in current knowledge on the configuration and use of the ancient floodplain. This study presents the results of a multi-disciplinary study aimed at mapping and dating ancient waterways in the Theban region and aims to find evidence for the natural or human origin of such channels. Boreholes and Electric Resistivity Tomography (ERT) were carried out along a transect that connects the edge of the Holocene floodplain with the current position of the river Nile. Satellite imagery and textual sources were also used to augment the fieldwork. The data indicate the presence of an infilled abandoned channel of the Nile in the western distal part of the current floodplain, adjoining the Funerary Temple complexes. Over 2100 ceramic fragments were analysed from the sedimentary infilling of the silted-up river course, dating it to the end of the New Kingdom, and indicating that the channel and temples were contemporary. The abundance of ceramic material also allowed the reconstruction of sedimentation rates across the floodplain, which ranged between 0.8-2.2 mm/yr, largely in agreement with estimates from other studies. Importantly, there seems to have been a major decrease in sedimentation rates after the New Kingdom. Furthermore, the abandonment of the secondary channel of the Nile and the formation of a well-developed calcareous palaeosol (both of which could have been forced by drought and failing Nile floods) correlate with the demise of the New Kingdom. This suggests that regionally observed cultural and natural dynamics may have been driven by hydroclimatic variability in the larger Nile basin. A lower calcareous palaeosol, located at least 1m below the New Kingdom horizon, hints at a previous period of severe drought and its age is tentatively inferred as Old Kingdom. The age of this lower palaeosol needs to be confirmed by more precise dating, but could support the idea that cultural dynamics in ancient floodwater farming cultures are strongly linked to hydroclimatic change.

Effective elastic thickness along the conjugate passive margins of India, Madagascar and Antarctica: A re-evaluation using the Hermite multitaper Bouguer coherence application

NASA Astrophysics Data System (ADS)

Ratheesh-Kumar, R. T.; Xiao, Wenjiao

2018-05-01

Gondwana correlation studies had rationally positioned the western continental margin of India (WCMI) against the eastern continental margin of Madagascar (ECMM), and the eastern continental margin of India (ECMI) against the eastern Antarctica continental margin (EACM). This contribution computes the effective elastic thickness (Te) of the lithospheres of these once-conjugated continental margins using the multitaper Bouguer coherence method. The results reveal significantly low strength values (Te ∼ 2 km) in the central segment of the WCMI that correlate with consistently low Te values (2-3 km) obtained throughout the entire marginal length of the ECMM. This result is consistent with the previous Te estimates of these margins, and confirms the idea that the low-Te segments in the central part of the WCMI and along the ECMM represents paleo-rift inception points of the lithospheric margins that was thermally and mechanically weakened by the combined action of the Marion hotspot and lithospheric extension during the rifting. The uniformly low-Te value (∼2 km) along the EACM indicates a mechanically weak lithospheric margin, probably due to considerable stretching of the lithosphere, considering the fact that this margin remained almost stationary throughout its rift history. In contrast, the ECMI has comparatively high-Te variations (5-11 km) that lack any correlation with the regional tectonic setting. Using gravity forward and inversion applications, we find a leading order of influence of sediment load on the flexural properties of this marginal lithosphere. The study concludes that the thick pile of the Bengal Fan sediments in the ECMI masks and has erased the signal of the original load-induced topography, and its gravity effect has biased the long-wavelength part of the observed gravity signal. The hence uncorrelated flat topography and deep lithospheric flexure together contribute a bias in the flexure modeling, which likely accounts a relatively high Te estimate.

Benthic Oxygen Uptake in the Arctic Ocean Margins - A Case Study at the Deep-Sea Observatory HAUSGARTEN (Fram Strait)

PubMed Central

Cathalot, Cecile; Rabouille, Christophe; Sauter, Eberhard; Schewe, Ingo; Soltwedel, Thomas

2015-01-01

The past decades have seen remarkable changes in the Arctic, a hotspot for climate change. Nevertheless, impacts of such changes on the biogeochemical cycles and Arctic marine ecosystems are still largely unknown. During cruises to the deep-sea observatory HAUSGARTEN in July 2007 and 2008, we investigated the biogeochemical recycling of organic matter in Arctic margin sediments by performing shipboard measurements of oxygen profiles, bacterial activities and biogenic sediment compounds (pigment, protein, organic carbon, and phospholipid contents). Additional in situ oxygen profiles were performed at two sites. This study aims at characterizing benthic mineralization activity along local bathymetric and latitudinal transects. The spatial coverage of this study is unique since it focuses on the transition from shelf to Deep Ocean, and from close to the ice edge to more open waters. Biogeochemical recycling across the continental margin showed a classical bathymetric pattern with overall low fluxes except for the deepest station located in the Molloy Hole (5500 m), a seafloor depression acting as an organic matter depot center. A gradient in benthic mineralization rates arises along the latitudinal transect with clearly higher values at the southern stations (average diffusive oxygen uptake of 0.49 ± 0.18 mmol O2 m-2 d-1) compared to the northern sites (0.22 ± 0.09 mmol O2 m-2 d-1). The benthic mineralization activity at the HAUSGARTEN observatory thus increases southward and appears to reflect the amount of organic matter reaching the seafloor rather than its lability. Although organic matter content and potential bacterial activity clearly follow this gradient, sediment pigments and phospholipids exhibit no increase with latitude whereas satellite images of surface ocean chlorophyll a indicate local seasonal patterns of primary production. Our results suggest that predicted increases in primary production in the Arctic Ocean could induce a larger export of more refractory organic matter due to the longer production season and the extension of the ice-free zone. PMID:26465885

Phosphate rock formation and marine phosphorus geochemistry: the deep time perspective.

PubMed

Filippelli, Gabriel M

2011-08-01

The role that phosphorite formation, the ultimate source rock for fertilizer phosphate reserves, plays in the marine phosphorus (P) cycle has long been debated. A shift has occurred from early models that evoked strikingly different oceanic P cycling during times of widespread phosphorite deposition to current thinking that phosphorite deposits may be lucky survivors of a series of inter-related tectonic, geochemical, sedimentological, and oceanic conditions. This paradigm shift has been facilitated by an awareness of the widespread nature of phosphogenesis-the formation of authigenic P-bearing minerals in marine sediments that contributes to phosphorite formation. This process occurs not just in continental margin sediments, but in deep sea oozes as well, and helps to clarify the driving forces behind phosphorite formation and links to marine P geochemistry. Two processes come into play to make phosphorite deposits: chemical dynamism and physical dynamism. Chemical dynamism involves the diagenetic release and subsequent concentration of P-bearing minerals particularly in horizons, controlled by a number of sedimentological and biogeochemical factors. Physical dynamism involves the reworking and sedimentary capping of P-rich sediments, which can either concentrate the relatively heavy and insoluble disseminated P-bearing minerals or provide an episodic change in sedimentology to concentrate chemically mobilized P. Both processes can result from along-margin current dynamics and/or sea level variations. Interestingly, net P accumulation rates are highest (i.e., the P removal pump is most efficient) when phosphorites are not forming. Both physical and chemical pathways involve processes not dominant in deep sea environments and in fact not often coincide in space and time even on continental margins, contributing to the rarity of high-quality phosphorite deposits and the limitation of phosphate rock reserves. This limitation is becoming critical, as the human demand for P far outstrips the geologic replacement for P and few prospects exist for new discoveries of phosphate rock. Copyright © 2011 Elsevier Ltd. All rights reserved.

Deposition and Burial Efficiency of Terrestrial Organic Carbon Exported from Small Mountainous Rivers to the Continental Margin, Southwest of Taiwan

NASA Astrophysics Data System (ADS)

Hsu, F.; Lin, S.; Wang, C.; Huh, C.

2007-12-01

Terrestrial organic carbon exported from small mountainous river to the continental margin may play an important role in global carbon cycle and it?|s biogeochemical process. A huge amount of suspended materials from small rivers in southwestern Taiwan (104 million tons per year) could serve as major carbon source to the adjacent ocean. However, little is know concerning fate of this terrigenous organic carbon. The purpose of this study is to calculate flux of terrigenous organic carbon deposited in the continental margin, offshore southwestern Taiwan through investigating spatial variation of organic carbon content, organic carbon isotopic compositions, organic carbon deposition rate and burial efficiency. Results show that organic carbon compositions in sediment are strongly influenced by terrestrial material exported from small rivers in the region, Kaoping River, Tseng-wen River and Er-jan Rver. In addition, a major part of the terrestrial materials exported from the Kaoping River may bypass shelf region and transport directly into the deep sea (South China Sea) through the Kaoping Canyon. Organic carbon isotopic compositions with lighter carbon isotopic values are found near the Kaoping River and Tseng-wen River mouth and rapidly change from heavier to lighter values through shelf to slope. Patches of lighter organic carbon isotopic compositions with high organic carbon content are also found in areas west of Kaoping River mouth, near the Kaoshiung city. Furthermore, terrigenous organic carbons with lighter isotopic values are found in the Kaoping canyon. A total of 0.028 Mt/yr of terrestrial organic carbon was found in the study area, which represented only about 10 percent of all terrestrial organic carbon deposited in the study area. Majority (~90 percent) of the organic carbon exported from the Kaoping River maybe directly transported into the deep sea (South China Sea) and become a major source of organic carbon in the deep sea.

Turnover of microbial lipids in the deep biosphere and growth of benthic archaeal populations

PubMed Central

Xie, Sitan; Lipp, Julius S.; Wegener, Gunter; Ferdelman, Timothy G.; Hinrichs, Kai-Uwe

2013-01-01

Deep subseafloor sediments host a microbial biosphere with unknown impact on global biogeochemical cycles. This study tests previous evidence based on microbial intact polar lipids (IPLs) as proxies of live biomass, suggesting that Archaea dominate the marine sedimentary biosphere. We devised a sensitive radiotracer assay to measure the decay rate of ([14C]glucosyl)-diphytanylglyceroldiether (GlcDGD) as an analog of archaeal IPLs in continental margin sediments. The degradation kinetics were incorporated in model simulations that constrained the fossil fraction of subseafloor IPLs and rates of archaeal turnover. Simulating the top 1 km in a generic continental margin sediment column, we estimated degradation rate constants of GlcDGD being one to two orders of magnitude lower than those of bacterial IPLs, with half-lives of GlcDGD increasing with depth to 310 ky. Given estimated microbial community turnover times of 1.6–73 ky in sediments deeper than 1 m, 50–96% of archaeal IPLs represent fossil signals. Consequently, previous lipid-based estimates of global subseafloor biomass probably are too high, and the widely observed dominance of archaeal IPLs does not rule out a deep biosphere dominated by Bacteria. Reverse modeling of existing concentration profiles suggest that archaeal IPL synthesis rates decline from around 1,000 pg⋅mL−1 sediment⋅y−1 at the surface to 0.2 pg⋅mL−1⋅y−1 at 1 km depth, equivalent to production of 7 × 105 to 140 archaeal cells⋅mL−1 sediment⋅y−1, respectively. These constraints on microbial growth are an important step toward understanding the relationship between the deep biosphere and the carbon cycle. PMID:23530229

Biogeochemical Implications of Recent Changes in the Ventilation of the Japan/East Sea

NASA Astrophysics Data System (ADS)

Jenkins, W. J.

2006-12-01

The Japan/East Sea (JES) is a highly productive marine ecosystem that constitutes an important fisheries resource for a number of nations. As a weakly stratified marginal sea separated from the Pacific Ocean by shallow straits, the ventilation of the abyssal JES is remarkably susceptible to climate change. Not surprisingly, such changes have indeed been noted for the late-glacial and Holocene. Over the past half-century or more, there has been a trend toward increasing deep water temperatures, increasing dissolved inorganic nutrients, and decreasing dissolved oxygen levels that are consistent with a reduction in deep ventilation in recent decades. I present a minimum complexity model of the Japan Sea that utilize observations of the transient tracers CFCs, tritium, and 3He to place useful constraints on the character, magnitude, and timing of these changes. I describe these changes within the context of differing mechanisms for deep water formation and ventilation. The converse of ventilation is the return of deep nutrients to the surface ocean, which in turn forms the basis of the food pyramid, and hence the support for new primary production in this strategically important marginal sea. The tracer constrained model calculations suggest that the primary (convective) supply of inorganic nitrogen to the shallow JES reduced by nearly a factor of two (from 1.7 to 0.9 Tmoles) in the latter half of the 20^th century. I relate the changes in abyssal nutrient reflux to climatic modulation of water mass formation changes, and present the implications for water column remineralization processes. The implications of the large scale changes for the sustenance of fishery stocks is significant.

Turnover of microbial lipids in the deep biosphere and growth of benthic archaeal populations.

PubMed

Xie, Sitan; Lipp, Julius S; Wegener, Gunter; Ferdelman, Timothy G; Hinrichs, Kai-Uwe

2013-04-09

Deep subseafloor sediments host a microbial biosphere with unknown impact on global biogeochemical cycles. This study tests previous evidence based on microbial intact polar lipids (IPLs) as proxies of live biomass, suggesting that Archaea dominate the marine sedimentary biosphere. We devised a sensitive radiotracer assay to measure the decay rate of ([(14)C]glucosyl)-diphytanylglyceroldiether (GlcDGD) as an analog of archaeal IPLs in continental margin sediments. The degradation kinetics were incorporated in model simulations that constrained the fossil fraction of subseafloor IPLs and rates of archaeal turnover. Simulating the top 1 km in a generic continental margin sediment column, we estimated degradation rate constants of GlcDGD being one to two orders of magnitude lower than those of bacterial IPLs, with half-lives of GlcDGD increasing with depth to 310 ky. Given estimated microbial community turnover times of 1.6-73 ky in sediments deeper than 1 m, 50-96% of archaeal IPLs represent fossil signals. Consequently, previous lipid-based estimates of global subseafloor biomass probably are too high, and the widely observed dominance of archaeal IPLs does not rule out a deep biosphere dominated by Bacteria. Reverse modeling of existing concentration profiles suggest that archaeal IPL synthesis rates decline from around 1,000 pg⋅mL(-1) sediment⋅y(-1) at the surface to 0.2 pg⋅mL(-1)⋅y(-1) at 1 km depth, equivalent to production of 7 × 10(5) to 140 archaeal cells⋅mL(-1) sediment⋅y(-1), respectively. These constraints on microbial growth are an important step toward understanding the relationship between the deep biosphere and the carbon cycle.

West Nile virus outbreak among horses in New York State, 1999 and 2000.

PubMed Central

Trock, S. C.; Meade, B. J.; Glaser, A. L.; Ostlund, E. N.; Lanciotti, R. S.; Cropp, B. C.; Kulasekera, V.; Kramer, L. D.; Komar, N.

2001-01-01

West Nile (WN) virus was identified in the Western Hemisphere in 1999. Along with human encephalitis cases, 20 equine cases of WN virus were detected in 1999 and 23 equine cases in 2000 in New York. During both years, the equine cases occurred after human cases in New York had been identified. PMID:11585543

West Nile Virus Infection in Killer Whale, Texas, USA, 2007

PubMed Central

Wu, Guang; Anderson, Mark; Dalton, Les; Nilson, Erika; Wang, David

2011-01-01

In 2007, nonsuppurative encephalitis was identified in a killer whale at a Texas, USA, marine park. Panviral DNA microarray of brain tissue suggested West Nile virus (WNV); WNV was confirmed by reverse transcription PCR and sequencing. Immunohistochemistry demonstrated WNV antigen within neurons. WNV should be considered in cases of encephalitis in cetaceans. PMID:21801643

Mutation in West Nile Virus Structural Protein prM during Human Infection.

PubMed

Lustig, Yaniv; Lanciotti, Robert S; Hindiyeh, Musa; Keller, Nathan; Milo, Ron; Mayan, Shlomo; Mendelson, Ella

2016-09-01

A mutation leading to substitution of a key amino acid in the prM protein of West Nile virus (WNV) occurred during persistent infection of an immunocompetent patient. WNV RNA persisted in the patient's urine and serum in the presence of low-level neutralizing antibodies. This case demonstrates active replication of WNV during persistent infection.