1,562 research outputs found
Reply to a comment by Carol S. Prentice, Paul Mann, and Luis R. Peña on: âHistorical perspective on seismic hazard to Hispaniola and the northeast Caribbean regionâ by U. ten Brink et al.
Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 118 (2013): 1606â1608, doi:10.1002/jgrb.50147.2013-10-1
Significant earthquakes on the Enriquillo Fault System, Hispaniola, 1500â2010 : implications for seismic hazard
This paper is not subject to U.S. copyright. The definitive version was published in Bulletin of the Seismological Society of America 102 (2012): 18-30, doi:10.1785/0120110077.Historical records indicate frequent seismic activity along the north-east Caribbean plate boundary over the past 500 years, particularly on the island of Hispaniola. We use accounts of historical earthquakes to assign intensities and the intensity assignments for the 2010 Haiti earthquakes to derive an intensity attenuation relation for Hispaniola. The intensity assignments and the attenuation relation are used in a grid search to find source locations and magnitudes that best fit the intensity assignments.
Here we describe a sequence of devastating earthquakes on the Enriquillo fault system in the eighteenth century. An intensity magnitude MI 6.6 earthquake in 1701 occurred near the location of the 2010 Haiti earthquake, and the accounts of the shaking in the 1701 earthquake are similar to those of the 2010 earthquake. A series of large earthquakes migrating from east to west started with the 18 October 1751 MI 7.4â7.5 earthquake, probably located near the eastern end of the fault in the Dominican Republic, followed by the 21 November 1751 MI 6.6 earthquake near Port-au-Prince, Haiti, and the 3 June 1770 MI 7.5 earthquake west of the 2010 earthquake rupture. The 2010 Haiti earthquake may mark the beginning of a new cycle of large earthquakes on the Enriquillo fault system after 240 years of seismic quiescence. The entire Enriquillo fault system appears to be seismically active; Haiti and the Dominican Republic should prepare for future devastating earthquakes
Observations of seismicity and ground motion in the Northeast U.S. Atlantic Margin from oceanâbottom seismometer data
Author Posting. © Seismological Society of America, 2016. This article is posted here by permission of Seismological Society of America for personal use, not for redistribution. The definitive version was published in Seismological Research Letters 88 (2017): 23-31, doi:10.1785/0220160079.Earthquake data from two shortâperiod oceanâbottom seismometer (OBS) networks deployed for over a year on the continental slope off New York and southern New England were used to evaluate seismicity and ground motions along the continental margin. Our OBS networks located only one earthquake of McâŒ1.5 near the shelf edge during six months of recording, suggesting that seismic activity (MLg>3.0) of the margin as far as 150â200 km offshore is probably successfully monitored by land stations without the need for OBS deployments. The spectral acceleration from two local earthquakes recorded by the OBS was found to be generally similar to the acceleration from these earthquakes recorded at several seismic stations on land and to hybrid empirical acceleration relationships for eastern North America. Therefore, the seismic attenuation used for eastern North America can be extended in this region at least to the continental slope. However, additional offshore studies are needed to verify these preliminary conclusions.This project was partially
funded by the Nuclear Regulatory Commission under NRC
Job Number V6166.2017-11-0
Seismic imaging of deep low-velocity zone beneath the Dead Sea basin and transform fault : implications for strain localization and crustal rigidity
Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 33 (2006): L24314, doi:10.1029/2006GL027890.New seismic observations from the Dead Sea basin (DSB), a large pull-apart basin along the Dead Sea transform (DST) plate boundary, show a low velocity zone extending to a depth of 18 km under the basin. The lower crust and Moho are not perturbed. These observations are incompatible with the current view of mid-crustal strength at low temperatures and with support of the basin's negative load by a rigid elastic plate. Strain softening in the middle crust is invoked to explain the isostatic compensation and the rapid subsidence of the basin during the Pleistocene. Whether the deformation is influenced by the presence of fluids and by a long history of seismic activity on the DST, and what the exact softening mechanism is, remain open questions. The uplift surrounding the DST also appears to be an upper crustal phenomenon but its relationship to a mid-crustal strength minimum is less clear. The shear deformation associated with the transform plate boundary motion appears, on the other hand, to cut throughout the entire crust.Funded by USAID Middle Eastern Regional
Cooperation Program grant M21-012, with matching funds by the participating
institutions
Geologic controls on submarine slope failure along the central U.S. Atlantic margin : insights from the Currituck Slide Complex
© The Author(s), 2016. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Geology 385 (2017): 114-130, doi:10.1016/j.margeo.2016.10.007.Multiple styles of failure, ranging from densely spaced, mass transport driven canyons to
the large, slab-type slope failure of the Currituck Slide, characterize adjacent sections of
the central U.S. Atlantic margin that appear to be defined by variations in geologic
framework. Here we use regionally extensive, deep penetration multichannel seismic
(MCS) profiles to reconstruct the influence of the antecedent margin physiography on
sediment accumulation along the central U.S. Atlantic continental shelf-edge, slope, and
uppermost rise from the Miocene to Present. These data are combined with highresolution
sparker MCS reflection profiles and multibeam bathymetry data across the
Currituck Slide complex. Pre-Neogene allostratigraphic horizons beneath the slope are
generally characterized by low gradients and convex downslope profiles. This is followed
by the development of thick, prograded deltaic clinoforms during the middle Miocene.
Along-strike variations in morphology of a regional unconformity at the top of this
middle Miocene unit appear to have set the stage for differing styles of mass transport
along the margin. Areas north and south of the Currituck Slide are characterized by
oblique margin morphology, defined by an angular shelf-edge and a relatively steep
(>8°), concave slope profile. Upper slope sediment bypass, closely spaced submarine
canyons, and small, localized landslides confined to canyon heads and sidewalls characterize these sectors of the margin. In contrast, the Currituck region is defined by a
sigmoidal geometry, with a rounded shelf-edge rollover and gentler slope gradient (<6°).
Thick (>800 m), regionally continuous stratified slope deposits suggest the low gradient
Currituck region was a primary depocenter for fluvial inputs during multiple sea level
lowstands. These results imply that the rounded, gentle slope physiography developed
during the middle Miocene allowed for a relatively high rate of subsequent sediment
accumulation, thus providing a mechanism for compactionâinduced overpressure that
preconditioned the Currituck region for failure. Detailed examination of the regional
geological framework illustrates the importance of both sediment supply and antecedent
slope physiography in the development of large, potentially unstable depocenters along
passive margins.The U.S. Geological Survey, the
U.S. Nuclear Regulatory Commission and Coastal Carolina University funded this
research
Seabed fluid expulsion along the upper slope and outer shelf of the U.S. Atlantic continental margin
Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 41 (2014): 96-101, doi:10.1002/2013GL058048.Identifying the spatial distribution of seabed fluid expulsion features is crucial for understanding the substrate plumbing system of any continental margin. A 1100âkm stretch of the U.S. Atlantic margin contains more than 5000 pockmarks at water depths of 120âm (shelf edge) to 700âm (upper slope), mostly updip of the contemporary gas hydrate stability zone (GHSZ). Advanced attribute analyses of high-resolution multichannel seismic reflection data reveal gas-charged sediment and probable fluid chimneys beneath pockmark fields. A series of enhanced reflectors, inferred to represent hydrate-bearing sediments, occur within the GHSZ. Differential sediment loading at the shelf edge and warming-induced gas hydrate dissociation along the upper slope are the proposed mechanisms that led to transient changes in substrate pore fluid overpressure, vertical fluid/gas migration, and pockmark formation.The U.S.
Geological Survey and the U.S. Nuclear Regulatory Commission funded this
research.2014-07-0
Current situation of endemic mycosis in the Americas and the Caribbean: Proceedings of the first international meeting on endemic mycoses of the Americas (IMEMA)
Background: The Americas are home to biologically and clinically diverse endemic fungi, including Blastomyces, Coccidioides, Emergomyces, Histoplasma, Paracoccidioides and Sporothrix. In endemic areas with high risk of infection, these fungal pathogens represent an important public health problem. Objectives: This report aims to summarise the main findings of the regional analysis carried out on the status of the endemic mycoses of the Americas, done at the first International Meeting on Endemic Mycoses of the Americas (IMEMA). Methods: A regional analysis for the Americas was done, the 27 territories were grouped into nine regions. A SWOT analysis was done. Results: All territories reported availability of microscopy. Seventy percent of territories reported antibody testing, 67% of territories reported availability of Histoplasma antigen testing. None of the territories reported the use of (1â3)-ÎČ-d-glucan. Fifty two percent of territories reported the availability of PCR testing in reference centres (mostly for histoplasmosis). Most of the territories reported access to medications such as trimethoprim-sulfamethoxazole, itraconazole, voriconazole and amphotericin B (AMB) deoxycholate. Many countries had limited access to liposomal formulation of AMB and newer azoles, such as posaconazole and isavuconazole. Surveillance of these fungal diseases was minimal. Conclusions: A consensus emerged among meeting participants, this group concluded that endemic mycoses are neglected diseases, and due to their severity and lack of resources, the improvement of diagnosis, treatment and surveillance is needed.Fil: Caceres, Diego H.. Universidad Colegio Mayor de Nuestra Señora del Rosario; Colombia. Centers for Disease Control and Prevention; Estados UnidosFil: Echeverri Tirado, Laura C.. Universidad de Antioquia; ColombiaFil: Bonifaz, Alexandro. Hospital General de Mexico; MĂ©xicoFil: Adenis, Antoine. Inserm; FranciaFil: Gomez, Beatriz L.. Universidad Colegio Mayor de Nuestra Señora del Rosario; ColombiaFil: Bnada Flores, Claudia Lizett. Universidad Peruana Cayetano Heredia; PerĂșFil: Canteros, Cristina Elena. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Santos, Daniel Wagner. Universidade Federal do Maranhao; BrasilFil: Arathoon, Eduardo. AsociaciĂłn de Salud Integral; GuatemalaFil: Ramirez Soto, Elia. Centro Nacional de Enfermedades Tropicales; BoliviaFil: Queiroz-Telles, Flavio. Universidade Federal do ParanĂĄ; BrasilFil: Schwartz, Ilan S.. University of Alberta; CanadĂĄFil: Zurita, Jeannete. Pontificia Universidad CatĂłlica del Ecuador; EcuadorFil: Serra Damasceno, Lisandra. Universidade Estadual do CearĂĄ; BrasilFil: Garcia, Nataly. Sociedad Venezolana de MicrobiologĂa; VenezuelaFil: Fernandez, Norma B.. Universidad de Buenos Aires. Facultad de Medicina. Hospital de ClĂnicas General San MartĂn; ArgentinaFil: Chincha, Omayra. Universidad Peruana Cayetano Heredia; PerĂșFil: Araujo, Patricia. Ministerio de Salud PĂșblica y Bienestar Social; ParaguayFil: Rabagliati, Ricardo. No especifĂca;Fil: Chiller, Tom. Centers for Disease Control and Prevention; Estados UnidosFil: Giusiano, Gustavo Emilio. Universidad Nacional del Nordeste. Instituto de Medicina Regional; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Nordeste; Argentin
Risk Factors of Porcine Cysticercosis in the Eastern Cape Province, South Africa
There is a high prevalence of Taenia solium taeniosis/cysticercosis in humans and pigs in the Eastern Cape Province (ECP) of South Africa. The objective of this study was to identify risk factors of porcine cysticercosis in select districts of the ECP. Data were collected in 2003 by interviewing 217 pig producers from the area. Blood samples were collected from 261 of their pigs, which were tested using two enzyme-linked immunosorbent assays (ELISA) for the presence of antibodies to cysticercosis. Frequencies of both owner- and pig-level characteristics were determined. For pig-level analysis, all bivariable and multivariable associations were determined using the surveylogistic procedure of the SAS/STATÂź software to accommodate for the intraclass correlation that exists for clusters of pigs within one owner and for clusters of owners within a district. All tests for significance were performed at the αâ=â0.05 level, and adjusted odds ratios (aOR) and 95% confidence intervals (CI) were determined. Among the respondents, 48% of their households lacked a latrine, 98% slaughtered pigs at home, and 99% indicated that meat inspection services were not available. On bivariable analysis, there was a significant association between porcine infection and district (pâ=â0.003), breed (pâ=â0.041) and the absence of a latrine (pâ=â0.006). On multivariable analysis, the absence of a latrine was the only variable significantly associated with porcine infection (aORâ=â1.89; 95% CIâ=â1.07, 3.35) (pâ=â0.028). The increased odds of porcine infection with households lacking a latrine contributes to our understanding of the transmission of this parasite in the ECP. Determining and addressing the risk factors for T. solium infection can potentially lower the very high prevalence in humans and pigs in this endemic area
Bone Marrow-Derived Cells from Male Donors Do Not Contribute to the Endometrial Side Population of the Recipient
Accumulated evidence demonstrates the existence of bone marrow-derived cells origin in the endometria of women undergoing bone marrow transplantation (BMT). In these reports, cells of a bone marrow (BM) origin are able to differentiate into endometrial cells, although their contribution to endometrial regeneration is not yet clear. We have previously demonstrated the functional relevance of side population (SP) cells as the endogenous source of somatic stem cells (SSC) in the human endometrium. The present work aims to understand the presence and contribution of bone marrow-derived cells to the endometrium and the endometrial SP population of women who received BMT from male donors. Five female recipients with spontaneous or induced menstruations were selected and their endometrium was examined for the contribution of XY donor-derived cells using fluorescent in situ hybridization (FISH), telomapping and SP method investigation. We confirm the presence of XY donor-derived cells in the recipient endometrium ranging from 1.7% to 2.62%. We also identify 0.45â0.85% of the donor-derived cells in the epithelial compartment displaying CD9 marker, and 1.0â1.83% of the Vimentin-positive XY donor-derived cells in the stromal compartment. Although the percentage of endometrial SP cells decreased, possibly being due to chemotherapy applied to these patients, they were not formed by XY donor-derived cells, donor BM cells were not associated with the stem cell (SC) niches assessed by telomapping technique, and engraftment percentages were very low with no correlation between time from transplant and engraftment efficiency, suggesting random terminal differentiation. In conclusion, XY donor-derived cells of a BM origin may be considered a limited exogenous source of transdifferentiated endometrial cells rather than a cyclic source of BM donor-derived stem cells
Leveraging environmental research and observation networks to advance soil carbon science
Soil organic matter (SOM) is a critical ecosystem variable regulated by interacting physical, chemical and biological processes. Collaborative efforts to integrate perspectives, data, and models from interdisciplinary research and observation networks can significantly advance predictive understanding of SOM. We outline how integrating three networks â the LongâTerm Ecological Research, with a focus on ecological dynamics, the Critical Zone Observatories with strengths in landscape/geologic context, and the National Ecological Observatory Network with standardized multiâscale measurementsâcan advance SOM knowledge. This integration requires improved data dissemination and sharing, coordinated data collection activities, and enhanced collaboration between empiricists and modelers within and across networks
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