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Sample records for african seismic experiment

  1. Active seismic experiment

    NASA Technical Reports Server (NTRS)

    Kovach, R. L.; Watkins, J. S.; Talwani, P.

    1972-01-01

    The Apollo 16 active seismic experiment (ASE) was designed to generate and monitor seismic waves for the study of the lunar near-surface structure. Several seismic energy sources are used: an astronaut-activated thumper device, a mortar package that contains rocket-launched grenades, and the impulse produced by the lunar module ascent. Analysis of some seismic signals recorded by the ASE has provided data concerning the near-surface structure at the Descartes landing site. Two compressional seismic velocities have so far been recognized in the seismic data. The deployment of the ASE is described, and the significant results obtained are discussed.

  2. The viking seismic experiment.

    PubMed

    Anderson, D L; Duennebier, F K; Latham, G V; Toksöz, M F; Kovach, R L; Knight, T C; Lazarewicz, A R; Miller, W F; Nakamura, Y; Sutton, G

    1976-12-11

    A three-axis short-period seismometer is now operating on Mars in the Utopia Planitia region. The noise background correlates well with wind gusts. Although no quakes have been detected in the first 60 days of observation, it is premature to draw any conclusions about the seismicity of Mars. The instrument is expected to return data for at least 2 years.

  3. Seismicity of the Earth 1900-2013 East African Rift

    USGS Publications Warehouse

    Hayes, Gavin P.; Jones, Eric S.; Stadler, Timothy J.; Barnhart, William D.; McNamara, Daniel E.; Benz, Harley M.; Furlong, Kevin P.; Villaseñor, Antonio; Hayes, Gavin P.; Jones, Eric S.; Stadler, Timothy J.; Barnhart, William D.; McNamara, Daniel E.; Benz, Harley M.; Furlong, Kevin P.; Villaseñor, Antonio

    2014-01-01

    Rifting in East Africa is not all coeval; volcanism and faulting have been an ongoing phenomenon on the continent since the Eocene (~45 Ma). The rifting began in northern East Africa, and led to the separation of the Nubia (Africa) and Arabia plates in the Red Sea and Gulf of Aden, and in the Lake Turkana area at the Kenya-Ethiopia border. A Paleogene mantle superplume beneath East Africa caused extension within the Nubia plate, as well as a first order topographic high known as the African superswell which now includes most of the eastern and southern sectors of the Nubia plate. Widespread volcanism erupted onto much of the rising plateau in Ethiopia during the Eocene-Oligocene (45–29 Ma), with chains of volcanoes forming along the rift separating Africa and Arabia. Since the initiation of rifting in northeastern Africa, the system has propagated over 3,000 km to the south and southwest, and it experiences seismicity as a direct result of the extension and active magmatism.

  4. Surface-wave Tomography of East African Rift System using Ambient Seismic Noise

    NASA Astrophysics Data System (ADS)

    Kim, S.; Kang, T.; Baag, C.; Nyblade, A. A.

    2008-12-01

    The surface-wave tomography technique for the ambient seismic noise is applied to the east African rift system to investigate shallow crustal structures of the region. Even if the technique has been widely used in many regions to investigate crustal structure in the world, there have been difficulties in application of the technique to the east African region because of unstable data conditions of PASSCAL experiments. A meticulous check of record by record enables us of applying the technique to understand the tectonic environment of the region. The long-period data of one month showing good quality in cross-correlation results are used in this study. They are from the 1994-95 Tanzania Passive-Source Seismic Experiment for the Tanzania craton and its surrounding rift zone, and from the 2000-02 Ethiopia/Kenya Broadband Seismic Experiment and the adjacent permanent stations of the African Array for the Ethiopia rift. The Rayleigh- and Love-wave group-speed maps were inverted using LSQR algorithm for several period bands (5 - 50 s). The preliminary group-speed distribution maps yield results roughly consistent with regional geology. The tomographic images of the Tanzania region show a strong high velocity anomaly at the location corresponding to the Tanzania craton and low velocity anomalies at the surrounding rift regions. For the Ethiopia regions, the features of low velocity anomalies roughly agree with the Tertiary volcanic regions. Combining the Tanzania and Ethiopia broadband arrays, the outline of the east African rift system can be identified as the low velocity anomalies in the surface-wave tomographic results. The structural variation with depth and the feature of the regional shear-wave anisotropy of crust will be explored by converting group- speed dispersion curves into shear-wave velocity structure.

  5. Experiments on seismic metamaterials: molding surface waves.

    PubMed

    Brûlé, S; Javelaud, E H; Enoch, S; Guenneau, S

    2014-04-01

    Materials engineered at the micro- and nanometer scales have had a tremendous and lasting impact in photonics and phononics. At much larger scales, natural soils civil engineered at decimeter to meter scales may interact with seismic waves when the global properties of the medium are modified, or alternatively thanks to a seismic metamaterial constituted of a mesh of vertical empty inclusions bored in the initial soil. Here, we show the experimental results of a seismic test carried out using seismic waves generated by a monochromatic vibrocompaction probe. Measurements of the particles' velocities show a modification of the seismic energy distribution in the presence of the metamaterial in agreement with numerical simulations using an approximate plate model. For complex natural materials such as soils, this large-scale experiment was needed to show the practical feasibility of seismic metamaterials and to stress their importance for applications in civil engineering. We anticipate this experiment to be a starting point for smart devices for anthropic and natural vibrations. PMID:24745420

  6. Experiments on seismic metamaterials: molding surface waves.

    PubMed

    Brûlé, S; Javelaud, E H; Enoch, S; Guenneau, S

    2014-04-01

    Materials engineered at the micro- and nanometer scales have had a tremendous and lasting impact in photonics and phononics. At much larger scales, natural soils civil engineered at decimeter to meter scales may interact with seismic waves when the global properties of the medium are modified, or alternatively thanks to a seismic metamaterial constituted of a mesh of vertical empty inclusions bored in the initial soil. Here, we show the experimental results of a seismic test carried out using seismic waves generated by a monochromatic vibrocompaction probe. Measurements of the particles' velocities show a modification of the seismic energy distribution in the presence of the metamaterial in agreement with numerical simulations using an approximate plate model. For complex natural materials such as soils, this large-scale experiment was needed to show the practical feasibility of seismic metamaterials and to stress their importance for applications in civil engineering. We anticipate this experiment to be a starting point for smart devices for anthropic and natural vibrations.

  7. Experiments on Seismic Metamaterials: Molding Surface Waves

    NASA Astrophysics Data System (ADS)

    Brûlé, S.; Javelaud, E. H.; Enoch, S.; Guenneau, S.

    2014-04-01

    Materials engineered at the micro- and nanometer scales have had a tremendous and lasting impact in photonics and phononics. At much larger scales, natural soils civil engineered at decimeter to meter scales may interact with seismic waves when the global properties of the medium are modified, or alternatively thanks to a seismic metamaterial constituted of a mesh of vertical empty inclusions bored in the initial soil. Here, we show the experimental results of a seismic test carried out using seismic waves generated by a monochromatic vibrocompaction probe. Measurements of the particles' velocities show a modification of the seismic energy distribution in the presence of the metamaterial in agreement with numerical simulations using an approximate plate model. For complex natural materials such as soils, this large-scale experiment was needed to show the practical feasibility of seismic metamaterials and to stress their importance for applications in civil engineering. We anticipate this experiment to be a starting point for smart devices for anthropic and natural vibrations.

  8. Apollo 14 active seismic experiment.

    NASA Technical Reports Server (NTRS)

    Watkins, J. S.; Kovach, R. L.

    1972-01-01

    Explosion seismic refraction data indicate that the lunar near-surface rocks at the Apollo 14 site consist of a regolith 8.5 meters thick and characterized by a compressional wave velocity of 104 meters per second. The regolith is underlain by a layer with a compressional wave velocity of 299 meters per second. The thickness of this layer, which we interpret to be the Fra Mauro Formation, is between 16 and 76 meters. The layer immediately beneath this has a velocity greater than 370 meters per second. We found no evidence of permafrost.

  9. Permafrost Active Layer Seismic Interferometry Experiment (PALSIE).

    SciTech Connect

    Abbott, Robert; Knox, Hunter Anne; James, Stephanie; Lee, Rebekah; Cole, Chris

    2016-01-01

    We present findings from a novel field experiment conducted at Poker Flat Research Range in Fairbanks, Alaska that was designed to monitor changes in active layer thickness in real time. Results are derived primarily from seismic data streaming from seven Nanometric Trillium Posthole seismometers directly buried in the upper section of the permafrost. The data were evaluated using two analysis methods: Horizontal to Vertical Spectral Ratio (HVSR) and ambient noise seismic interferometry. Results from the HVSR conclusively illustrated the method's effectiveness at determining the active layer's thickness with a single station. Investigations with the multi-station method (ambient noise seismic interferometry) are continuing at the University of Florida and have not yet conclusively determined active layer thickness changes. Further work continues with the Bureau of Land Management (BLM) to determine if the ground based measurements can constrain satellite imagery, which provide measurements on a much larger spatial scale.

  10. Lunar seismic profiling experiment natural activity study

    NASA Technical Reports Server (NTRS)

    Duennebier, F. K.

    1976-01-01

    The Lunar Seismic Experiment Natural Activity Study has provided a unique opportunity to study the high frequency (4-20 Hz) portion to the seismic spectrum on the moon. The data obtained from the LSPE was studied to evaluate the origin and importance of the process that generates thermal moonquakes and the characteristics of the seismic scattering zone at the lunar surface. The detection of thermal moonquakes by the LSPE array made it possible to locate the sources of many events and determine that they are definitely not generated by astronaut activities but are the result of a natural process on the moon. The propagation of seismic waves in the near-surface layers was studied in a qualitative manner. In the absence of an adequate theoretical model for the propagation of seismic waves in the moon, it is not possible to assign a depth for the scattering layer. The LSPE data does define several parameters which must be satisfied by any model developed in the future.

  11. The SEIS Experiment: A Mars Seismic Package

    NASA Technical Reports Server (NTRS)

    Schibler, P.; Lognonne, P.; Giardini, D.; Banerdt, B.; Karczewski, J. F.; Mimoun, D.; Zweifel, P.; Pike, T.; Ammann, J.; Anglade, A.

    2003-01-01

    This experiment will integrate a VBB (Very Broad Band) two axis seismometer, a three axis Short Period seismometer and a series of environmental sensors for pressure, infra-sounds and temperature. IPGP (France) has the overall responsibility of the experiment and is responsible for the VBB and environmental sensors. ETHZ (Switzerland) is responsible for the electronics of the experiment and JPL (USA) for the SP (Short Period) sensors. SEIS instrument was first proposed and accepted for NetLander mission (and will also be in charge of data acquisition for SPICE experiment). This seismic package should also be proposed for future missions.

  12. Rivera Ocean Seismic Experiment (ROSE) overview

    NASA Astrophysics Data System (ADS)

    Ewing, J. I.; Meyer, Robert P.

    1982-10-01

    The Rivera Ocean Seismic Experiment (ROSE) was designed as a combined sea and land seismic program to utilize both explosive sources and earthquakes to study a number of features of the structure and evolution of a mid-ocean ridge, a major oceanic fracture zone, and the transition region between ocean and continent. The primary region selected for the experiment included the Rivera Fracture Zone, the crest and eastern flank of the East Pacific Rise north of the Rivera, and adjacent areas of Baja California and mainland Mexico. These areas were to be instrumented with land and ocean bottom seismographs in order to determine good source parameter and location data for natural events and to record these events along a large number of paths crossing various parts of the region. Explosive charges were to be detonated at sea to supplement the natural events. However, the necessary permission to conduct the experiment was not received from Mexican authorities; therefore an alternate plan was implemented whereby the marine program had to be moved southward outside of territorial waters. This had the effect of transforming this experiment into three, almost independent components: (1) an experiment to study the East Pacific Rise south of the Orozco Fracture Zone primarily using ocean bottom recording and explosive sources, (2) a seismicity program at the Orozco, and (3) a land-based program of recording natural events along the coastal region of Mexico. A considerable amount of useful data was obtained in each of the three subprograms. In the marine parts of the experiment we were able to address a variety of problems including structure and evolution of young oceanic crust and mantle, structure and dynamics of the East Pacific Rise, seismicity of the Orozco Fracture Zone, and partitioning of energy transmission between the ocean volume and the crust/lithosphere. On land, the fortuitous occurrence of the Petatlan M7.6 earthquake of March 14, 1979, permitted the acquisition

  13. Cataloging the Pan-African Experience

    ERIC Educational Resources Information Center

    Hayes, Dianne

    2012-01-01

    Of all the honors and accolades bibliophile and noted authority on the Underground Railroad Charles Blockson has received, being bequeathed recently with some of Harriet Tubman's personal items by her great-niece is one of the most significant experiences of his life. A longtime collector of books and rare items by and about African-Americans,…

  14. South African TOPEX/Poseidon altimeter experiment

    NASA Technical Reports Server (NTRS)

    Gruendlingh, Marten L.; Shannon, L. V.; Lutjeharms, J. R.

    1991-01-01

    The area surrounding the southern tip of Africa contains a juxtaposition of a variety of interesting and climatically relevant features. On the Indian Ocean side, the Agulhas Current with its tributaries form a conduit through which much of the southern Indian Ocean surface flow is focused. South of the continent, this flow is fragmented and partially injected into the Atlantic Ocean and across the Subtropical Convergence into the Southern Ocean. To the west of the subcontinent, the circulation of the South Atlantic subtropical gyre in the Cape Basin interacts with the vigorous Benguela upwelling regime. The creation, transformation, and transport of water masses and the intra-annual and climatic importance of all these processes have been specifically recognized by the World Ocean Circulation Experiment (WOCE). The South African TOPEX/POSEIDON Altimeter Experiment addresses many of these issues through four mutually complementary and interrelated subprojects.

  15. Recent seismicity of the East African Rift system and its implications

    NASA Astrophysics Data System (ADS)

    Kebede, Fekadu; Kulhánek, Ota

    1991-09-01

    The seismicity of the East African Rift system and southern Red Sea is studied here. Location of earthquake epicenters in East Africa shows that there is a seismicity gap in space and time between the Main Ethiopian Rift system and the eastern rift. However, distribution of earthquake epicenters together with the energy mapping suggest a continuity of seismic activity or stress field from the Main Ethiopian Rift system to the western rift system via the southernmost rifts of Ethiopia. In general (except for some earthquakes which occurred at different complex tectonics regions) mechanisms of earthquakes studied here show dominantly normal faulting suggesting that the rift system is an extensional zone on the continent. The presence of greater focal depth earthquakes to the southern part of the rift system may indicate that softer materials at a shallower depth are present in Afar and neighboring regions than in the remaining part of the East African Rift system. This interpretation is supported by other geophysical studies (low electrical resistivity and gravity data) performed in Afar. It is also supported by low and high stress drops found for the northern part (Afar depression) and southern part of the East African Rift system, respectively.

  16. The Northern Walker Lane Seismic Refraction Experiment

    NASA Astrophysics Data System (ADS)

    Louie, J. N.; Smith, S. B.; Thelen, W.; Scott, J. B.; Clark, M.

    2002-12-01

    We are developing a three-dimensional reference seismic velocity model for the western Great Basin region of Nevada and eastern California. The northern Walker Lane had not been characterized well by previous work. In May 2002 we collected a new crustal refraction profile from Battle Mountain, Nev. across western Nevada, the Reno area, Lake Tahoe, and the northern Sierra to Auburn, Calif. Mine blasts and earthquakes were recorded by 199 Texan instruments (loaned by the PASSCAL Instrument Center) extending across this more than 450-km-long transect. The seismic sources at the eastern end were mining blasts at Barrick's GoldStrike pit. We recorded additional blasts at the Florida Canyon and other mines between Lovelock and Battle Mountain, Nevada. The GoldStrike mine produced several ripple-fired blasts using 10,000-40,000 kg of ANFO each. First arrivals from the larger blasts are obvious to distances exceeding 250 km in the raw records. A M2.4 earthquake near Bridgeport, Calif. also produced pickable P-wave arrivals across at least half the transect, providing fan-shot data. We recorded only during working hours, and so missed an M4 earthquake that occurred at night. Events of M2 occurred during our recording to the west on the San Andreas fault near Pinnacles, Calif.; M3 events occurred near Portola and Mammoth Lakes, Calif. Arrivals from M5 events in the Mariana and Kuril Islands also appear in the records. Time-picks from these earthquakes may be possible after more work on synthetic-time modeling, data filtering, and display. We plan to record blasts at quarries in the western Sierra in future experiments, for a direct refraction reversal. We will compare our time picks against times generated from regional velocity models, to identify potential crustal and upper-mantle velocity anomalies. Such anomalies may be associated with the Battle Mountain heat-flow high, the northern Walker Lane belt, or the northern Sierran block.

  17. Upper mantle structure beneath southern African cratons from seismic finite-frequency P- and S-body wave tomography

    NASA Astrophysics Data System (ADS)

    Youssof, M.; Thybo, H.; Artemieva, I. M.; Levander, A.

    2015-06-01

    We present a 3D high-resolution seismic model of the southern African cratonic region from teleseismic tomographic inversion of the P- and S-body wave dataset recorded by the Southern African Seismic Experiment (SASE). Utilizing 3D sensitivity kernels, we invert traveltime residuals of teleseismic body waves to calculate velocity anomalies in the upper mantle down to a 700 km depth with respect to the ak135 reference model. Various resolution tests allow evaluation of the extent of smearing effects and help defining the optimum inversion parameters (i.e., damping and smoothness) for regularizing the inversion calculations. The fast lithospheric keels of the Kaapvaal and Zimbabwe cratons reach depths of 300-350 km and 200-250 km, respectively. The paleo-orogenic Limpopo Belt is represented by negative velocity perturbations down to a depth of ˜ 250 km, implying the presence of chemically fertile material with anomalously low wave speeds. The Bushveld Complex has low velocity down to ˜ 150 km, which is attributed to chemical modification of the cratonic mantle. In the present model, the finite-frequency sensitivity kernels allow to resolve relatively small-scale anomalies, such as the Colesberg Magnetic Lineament in the suture zone between the eastern and western blocks of the Kaapvaal Craton, and a small northern block of the Kaapvaal Craton, located between the Limpopo Belt and the Bushveld Complex.

  18. Planning and conducting an international seismic data exchange experiment at the center for seismic studies

    NASA Astrophysics Data System (ADS)

    Romney, C.; Huszar, L.; Frazier, G. A.; Campanella, A.; Tiberio, M. A.

    1986-01-01

    This report covers preparations for and the conduct of an international seismic data exchange experiment sponsored by the Group of Scientific Experts, U.N. Conference on Disarmament. Seismic data reports from 37 countries were transmitted over circuits of the WMO/GTS. The data were analyzed at centers in Washington, Moscow and Stockholm and epicenter lists were broadcast to participants. The experiment tested a number of aspects of a proposed nuclear test monitoring system.

  19. Shallow lunar structure determined from the passive seismic experiment

    NASA Technical Reports Server (NTRS)

    Nakamura, Y.; Dorman, J.; Duennebier, F.; Lammlein, D.; Latham, G.

    1975-01-01

    Data relevant to the shallow structure of the moon obtained at the Apollo seismic stations are compared with previously published results of the active seismic experiments. It is concluded that the lunar surface is covered by a layer of low seismic velocity which appears to be equivalent to the lunar regolith defined previously by geological observations. This layer is underlain by a zone of distinctly higher seismic velocity at all of the Apollo landing sites. The regolith thicknesses at the Apollo 11, 12, and 15 sites are estimated from the shear-wave resonance to be 4.4, 3.7, and 4.4 m, respectively. These thicknesses and those determined at the other Apollo sites by the active seismic experiments appear to be correlated with the age determinations and the abundances of extralunar components at the sites.

  20. Observational studies in South African mines to mitigate seismic risks: implications for mine safety and tectonic earthquakes

    NASA Astrophysics Data System (ADS)

    Durrheim, Raymond; Ogaswara, Hiroshi; Nakatani, Masao; Yabe, Yasuo; Milev, Alexander; Cichowicz, Artur; Kawakata, Hironori; Moriya, Hirokazu; Naoi, Makoto; Kgarume, Thabang; Murakami, Osamu; Mngadi, Siyanda

    2014-05-01

    Seismicity poses a significant risk to workers in deep and overstressed mines, such as the gold mines in the Witwatersrand basin of South Africa, as well as inhabitants of earthquake-prone regions such as Japan. A 5-year collaborative project entitled "Observational studies in South African mines to mitigate seismic risks" was launched in 2010 to address these risks, drawing on over a century of South African and Japanese research experience with respect to mining-related and tectonic earthquakes, respectively. The project has three main aims: (1) to learn more about earthquake preparation and triggering mechanisms by deploying arrays of sensitive sensors within rock volumes where mining is likely to induce seismic activity; (2) to learn more about earthquake rupture and rockburst damage phenomena by deploying robust strong ground motion sensors close to potential fault zones and on stope hangingwalls; and (3) to upgrade the South African surface national seismic network in the mining districts. Research sites have been established at mines operated by Sibanye Gold (Hlanganani Shaft and Cooke #4 Shaft) and Anglogold Ashanti (Moab-Khotsong). More than 70 boreholes (totalling more than 2.8 km in length) have been drilled to locate "capable" faults i.e. faults that are considered likely to become seismically active as a result of mining activity and to deploy sensors. Acoustic emission sensors, strain- and tilt meters, and controlled seismic sources were installed to monitor the deformation of the rock mass, the accumulation of damage during the earthquake preparation phase, and changes in dynamic stress produced by the propagation of the rupture front. These data are being integrated with measurements of rock properties, stope closure, stope strong motion, seismic data recorded by the mine-wide network, and stress modelling. The mid-point of the 5-year project has passed. New observations of stress and the response of the rock mass to mining have already been made

  1. Cancer and the African American Experience

    Cancer.gov

    The first plenary of the EPEC-O (Education in Palliative and End-of-Life Care for Oncology) Self-Study: Cultural Considerations When Caring for African Americans explores the many factors that lead to inequalities in cancer care outcomes for African Americans.

  2. Mammoth Mountain, California broadband seismic experiment

    NASA Astrophysics Data System (ADS)

    Dawson, P. B.; Pitt, A. M.; Wilkinson, S. K.; Chouet, B. A.; Hill, D. P.; Mangan, M.; Prejean, S. G.; Read, C.; Shelly, D. R.

    2013-12-01

    Mammoth Mountain is a young cumulo-volcano located on the southwest rim of Long Valley caldera, California. Current volcanic processes beneath Mammoth Mountain are manifested in a wide range of seismic signals, including swarms of shallow volcano-tectonic earthquakes, upper and mid-crustal long-period earthquakes, swarms of brittle-failure earthquakes in the lower crust, and shallow (3-km depth) very-long-period earthquakes. Diffuse emissions of C02 began after a magmatic dike injection beneath the volcano in 1989, and continue to present time. These indications of volcanic unrest drive an extensive monitoring effort of the volcano by the USGS Volcano Hazards Program. As part of this effort, eleven broadband seismometers were deployed on Mammoth Mountain in November 2011. This temporary deployment is expected to run through the fall of 2013. These stations supplement the local short-period and broadband seismic stations of the Northern California Seismic Network (NCSN) and provide a combined network of eighteen broadband stations operating within 4 km of the summit of Mammoth Mountain. Data from the temporary stations are not available in real-time, requiring the merging of the data from the temporary and permanent networks, timing of phases, and relocation of seismic events to be accomplished outside of the standard NCSN processing scheme. The timing of phases is accomplished through an interactive Java-based phase-picking routine, and the relocation of seismicity is achieved using the probabilistic non-linear software package NonLinLoc, distributed under the GNU General Public License by Alomax Scientific. Several swarms of shallow volcano-tectonic earthquakes, spasmodic bursts of high-frequency earthquakes, a few long-period events located within or below the edifice of Mammoth Mountain and numerous mid-crustal long-period events have been recorded by the network. To date, about 900 of the ~2400 events occurring beneath Mammoth Mountain since November 2011 have

  3. 2013 East Bay Seismic Experiment (EBSE): implosion data, Hayward, Calif

    USGS Publications Warehouse

    Catchings, Rufus D.; Strayer, Luther M.; Goldman, Mark R.; Criley, Coyn J.; Garcia, Susan; Sickler, Robert R.; Catchings, Marisol K.; Chan, Joanne; Gordon, Leslie C.; Haefner, Scott; Blair, James Luke; Gandhok, Gini; Johnson, Michaela R.

    2015-01-01

    In August 2013, the California State University, East Bay (CSUEB) in Hayward, California imploded a 13-story building (Warren Hall) that was deemed unsafe because of its immediate proximity to the active trace of the Hayward Fault. The U.S. Geological Survey (USGS) and the CSUEB collaborated on a program to record the seismic waves generated by the collapse of the building. We refer to this collaboration as the East Bay Seismic Experiment (EBSE). The principal objective of recording the seismic energy was to observe ground shaking as it radiated from the source, but the data also may be useful for other purposes. For example, the seismic data may be useful in evaluating the implosion process as it relates to structural engineering purposes. This report provides the metadata needed to utilize the seismic data.

  4. The Mars SEIS Experiment: A Mars Seismic Package

    NASA Technical Reports Server (NTRS)

    Mimoun, D.; Lognonne, P.; Banerdt, W. B.; Schibler, P.; Giardini, D.; Pont, G.

    2005-01-01

    The Mars SEIS experiment. The SEIS experiment was first proposed by IPGP (and accepted) for the NetLander mission. It integrates two VBB (Very Broad Band) seismometers, a three axis Short Period seismometer and a series of environmental sensors for pressure, infra-sounds and temperature. IPGP (France) has the overall responsibility of the experiment and is responsible for the seismic and environmental sensors. ETHZ (Switzerland) is responsible for the electronics of the experiment and JPL (USA) for the SP (Short Period) sensors. As NetLander mission has been cancelled (while fortunately the development still goes on), this seismic package can be proposed for future Mars missions.

  5. Participation in the Apollo passive seismic experiment

    NASA Technical Reports Server (NTRS)

    Press, F.; Toksoez, M. N.; Dainty, A.

    1972-01-01

    Computer programs which were written to read digital tapes containing lunar seismic data were studied. Interpreting very early parts of the lunar seismogram as seismic body-wave phases enabled the determination of the structure of the outer part of the moon in the Fra Mauro region. The crust in the Fra Mauro region is 60 to 65 km-thick, overlaying a high velocity mantle. The crust is further divided into an upper part, 25 km thick, apparently made of material similar to the surficial basalts, and a lower part of seemingly different composition, possibly an anorthositic gabbro. The generation of the exceedingly long reverberating wave-train observed in lunar seismogram was also studied. This is believed to be due to an intense scattering layer with very high quality coefficient overlying a more homogeneous elastic medium. Titles and abstracts of related published papers are included.

  6. Results from the Apollo passive seismic experiment

    NASA Technical Reports Server (NTRS)

    Lathum, G.; Nakamura, Y.; Dorman, J.; Duennebier, F.; Ewing, M.; Lammlein, D.

    1974-01-01

    Recent results from the Apollo seismic network suggest that primitive differentiation occurred in the outer shell of the moon to a depth of approximately 300 km; and the central region of the moon is presently molten to a radius of between 200 and 300 km. If early melting to a depth of 300 to 400 km was a consequence of accretional energy, very short accretion times are required. The best model for the zone of original differentiation appears to be a crust 40 to 80 km thick, ranging in composition from anorthositic gabbro to gabbro; overlying an ultramafic cumulate (olivine-pyroxene) about 250 km thick. The best candidate for the molten core appears to be iron or iron sulphide. A new class of seismic signals has recently been identified that may correspond to shallow moonquakes. These are rare, but much more energetic than the more numerous, deep moonquakes.

  7. Results from the Apollo passive seismic experiment

    NASA Technical Reports Server (NTRS)

    Latham, G.; Nakamura, Y.; Dorman, J.; Duennebier, F.; Ewing, M.; Lammlein, D.

    1977-01-01

    Recent results from the Apollo Seismic Network suggest that primitive differentiation occurred in the outer shell of the moon to a depth of approximately 300 km and the central region of the moon is presently molten to a radius of between 200 and 300 km. If early melting to a depth of 300 to 400 km was a consequence of accretional energy, very short accretion times are required. It was shown that the best model for the zone of original differentiation is a crust 40 to 80 km thick, ranging in composition from anorthositic gabbro to gabbro, and overlying an ultramafic cumulate about 250 km thick. The best candidate for the molten core appears to be iron or iron sulphide. A new class of seismic signals recently were identified that may correspond to shallow moonquakes. These are rare, but much more energetic than the more numerous, deep moonquakes.

  8. Explosives for Lunar Seismic Profiling Experiment (LSPE)

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Explosive charges of various sizes were investigated for use in lunar seismic studies. Program logistics, and the specifications for procurement of bulk explosives are described. The differential analysis, thermal properties, and detonation velocity measurements on HNS/Teflon 7C 90/10 are reported along with the field tests of the hardware. It is concluded that nearly all large explosive charges crack after fabrication, from aging or thermal shock. The cracks do not affect the safety, or reliability of the explosives.

  9. The Lusi seismic experiment: An initial study to understand the effect of seismic activity to Lusi

    SciTech Connect

    Karyono; Mazzini, Adriano; Sugiharto, Anton; Lupi, Matteo; Syafri, Ildrem; Masturyono,; Rudiyanto, Ariska; Pranata, Bayu; Muzli,; Widodo, Handi Sulistyo; Sudrajat, Ajat

    2015-04-24

    The spectacular Lumpur Sidoarjo (Lusi) eruption started in northeast Java on the 29 of May 2006 following a M6.3 earthquake striking the island [1,2]. Initially, several gas and mud eruption sites appeared along the reactivated strike-slip Watukosek fault system [3] and within weeks several villages were submerged by boiling mud. The most prominent eruption site was named Lusi. The Lusi seismic experiment is a project aims to begin a detailed study of seismicity around the Lusi area. In this initial phase we deploy 30 seismometers strategically distributed in the area around Lusi and along the Watukosek fault zone that stretches between Lusi and the Arjuno Welirang (AW) complex. The purpose of the initial monitoring is to conduct a preliminary seismic campaign aiming to identify the occurrence and the location of local seismic events in east Java particularly beneath Lusi.This network will locate small event that may not be captured by the existing BMKG network. It will be crucial to design the second phase of the seismic experiment that will consist of a local earthquake tomography of the Lusi-AW region and spatial and temporal variations of vp/vs ratios. The goal of this study is to understand how the seismicity occurring along the Sunda subduction zone affects to the behavior of the Lusi eruption. Our study will also provide a large dataset for a qualitative analysis of earthquake triggering studies, earthquake-volcano and earthquake-earthquake interactions. In this study, we will extract Green’s functions from ambient seismic noise data in order to image the shallow subsurface structure beneath LUSI area. The waveform cross-correlation technique will be apply to all of recordings of ambient seismic noise at 30 seismographic stations around the LUSI area. We use the dispersive behaviour of the retrieved Rayleigh waves to infer velocity structures in the shallow subsurface.

  10. The Lusi seismic experiment: An initial study to understand the effect of seismic activity to Lusi

    NASA Astrophysics Data System (ADS)

    Karyono, Mazzini, Adriano; Lupi, Matteo; Syafri, Ildrem; Masturyono, Rudiyanto, Ariska; Pranata, Bayu; Muzli, Widodo, Handi Sulistyo; Sudrajat, Ajat; Sugiharto, Anton

    2015-04-01

    The spectacular Lumpur Sidoarjo (Lusi) eruption started in northeast Java on the 29 of May 2006 following a M6.3 earthquake striking the island [1,2]. Initially, several gas and mud eruption sites appeared along the reactivated strike-slip Watukosek fault system [3] and within weeks several villages were submerged by boiling mud. The most prominent eruption site was named Lusi. The Lusi seismic experiment is a project aims to begin a detailed study of seismicity around the Lusi area. In this initial phase we deploy 30 seismometers strategically distributed in the area around Lusi and along the Watukosek fault zone that stretches between Lusi and the Arjuno Welirang (AW) complex. The purpose of the initial monitoring is to conduct a preliminary seismic campaign aiming to identify the occurrence and the location of local seismic events in east Java particularly beneath Lusi.This network will locate small event that may not be captured by the existing BMKG network. It will be crucial to design the second phase of the seismic experiment that will consist of a local earthquake tomography of the Lusi-AW region and spatial and temporal variations of vp/vs ratios. The goal of this study is to understand how the seismicity occurring along the Sunda subduction zone affects to the behavior of the Lusi eruption. Our study will also provide a large dataset for a qualitative analysis of earthquake triggering studies, earthquake-volcano and earthquake-earthquake interactions. In this study, we will extract Green's functions from ambient seismic noise data in order to image the shallow subsurface structure beneath LUSI area. The waveform cross-correlation technique will be apply to all of recordings of ambient seismic noise at 30 seismographic stations around the LUSI area. We use the dispersive behaviour of the retrieved Rayleigh waves to infer velocity structures in the shallow subsurface.

  11. The MARINER Integrated Seismic and Geophysical Mapping Experiment (Invited)

    NASA Astrophysics Data System (ADS)

    Dunn, R. A.; Canales, J.; Sohn, R. A.; Paulatto, M.; Arai, R.; Szitkar, F.

    2013-12-01

    The MARINER (Mid-Atlantic Ridge INtegrated Experiments at Rainbow) seismic and geophysical mapping experiment was designed to examine the relationship between tectonic rifting, heat/melt supply, and oceanic core complex formation at a non-transform offset (NTO) of the Mid-Atlantic Ridge, 36°N, the site of the ultramafic-hosted Rainbow hydrothermal system. We present an overview of the components of the experiment and the various projects stemming from it. The 5-week experiment was carried out aboard the R/V M. G. Langseth in April-May 2013, and consisted of a 3D active-source seismic tomography experiment, 2D multi-channel seismic profiles, an on-going nine month passive micro-seismicity study, dense acoustic mapping of the seafloor (including depth and amplitude information), gravity field mapping, and magnetic field mapping. During the tomography experiment, we deployed 46 ocean bottom seismometers (OBS) over a 35 x 80 sq. km area centered on Rainbow. Twenty-six wide-angle seismic lines were carried out using the Langseth's 36-element source, generating ~175,000 seismic records. The MCS experiment, which was also recorded on 20 OBS, consisted of twenty-one densely spaced seismic lines using an 8-km-long hydrophone streamer. Bathymetry, gravity, and magnetic surveys were carried out over a broader, 80x105 sq. km, area centered on Rainbow. Overall, the experiment extends across two segments of the Mid-Atlantic Ridge separated by the Rainbow NTO massif. MARINER multi-beam bathymetry and acoustic imagery provide a broad view of the geologic and geophysical character of the ridge system, emphasizing the strong variability of ridge morphology, tectonics, and lava emplacement. The magnetization map shows a clear central anomaly with normal polarity, flanked by regions of negative polarity, consistent with the Brunhes-Matuyama reversal (~780,000 Ma). Rainbow itself lies in a region of weaker magnetization strength, which could be linked to a decrease in the depth of the

  12. Small Arrays for Seismic Intruder Detections: A Simulation Based Experiment

    NASA Astrophysics Data System (ADS)

    Pitarka, A.

    2014-12-01

    Seismic sensors such as geophones and fiber optic have been increasingly recognized as promising technologies for intelligence surveillance, including intruder detection and perimeter defense systems. Geophone arrays have the capability to provide cost effective intruder detection in protecting assets with large perimeters. A seismic intruder detection system uses one or multiple arrays of geophones design to record seismic signals from footsteps and ground vehicles. Using a series of real-time signal processing algorithms the system detects, classify and monitors the intruder's movement. We have carried out numerical experiments to demonstrate the capability of a seismic array to detect moving targets that generate seismic signals. The seismic source is modeled as a vertical force acting on the ground that generates continuous impulsive seismic signals with different predominant frequencies. Frequency-wave number analysis of the synthetic array data was used to demonstrate the array's capability at accurately determining intruder's movement direction. The performance of the array was also analyzed in detecting two or more objects moving at the same time. One of the drawbacks of using a single array system is its inefficiency at detecting seismic signals deflected by large underground objects. We will show simulation results of the effect of an underground concrete block at shielding the seismic signal coming from an intruder. Based on simulations we found that multiple small arrays can greatly improve the system's detection capability in the presence of underground structures. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344

  13. Bighorns Arch Seismic Experiment (BASE): Amplitude Response to Different Seismic Charge Configurations

    SciTech Connect

    Harder, S. H., Killer, K. C., Worthington, L. L., Snelson, C. M.

    2010-09-02

    Contrary to popular belief, charge weight is not the most important engineering parameter determining the seismic amplitudes generated by a shot. The scientific literature has long claimed that the relationship, A ~R2L1/2, where A is the seismic amplitude generated by a shot, R is the radius of the seismic charge and L is the length of that charge, holds. Assuming the coupling to the formation and the pressure generated by the explosive are constants, this relationship implies that the one should be able to increase the charge radius while decreasing the charge length and obtain more seismic amplitude with less charge weight. This has significant implications for the economics of lithospheric seismic shots, because shallower holes and small charge sizes decrease cost. During the Bighorns Array Seismic Experiment (BASE) conducted in the summer of 2010, 24 shots with charge sizes ranging from 110 to 900 kg and drill hole diameters of 300 and 450 mm were detonated and recorded by an array of up to 2000 single-channel Texan seismographs. Maximum source-receiver offset of 300 km. Five of these shots were located within a one-acre square in an effort to eliminate coupling effects due to differing geological formations. We present a quantitative comparison of the data from these five shots to experimentally test the equation above.

  14. The LUSI Seismic Experiment: Deployment of a Seismic Network around LUSI, East Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Karyono, Karyono; Mazzini, Adriano; Lupi, Matteo; Syafri, Ildrem; Haryanto, Iyan; Masturyono, Masturyono; Hadi, Soffian; Rohadi, Suprianto; Suardi, Iman; Rudiyanto, Ariska; Pranata, Bayu

    2015-04-01

    The spectacular Lusi eruption started in northeast Java, Indonesia the 29 of May 2006 following a M6.3 earthquake striking the island. Initially, several gas and mud eruption sites appeared along the reactivated strike-slip Watukosek fault system and within weeks several villages were submerged by boiling mud. The most prominent eruption site was named Lusi. Lusi is located few kilometres to the NE of the Arjuno-Welirang volcanic complex. Lusi sits upon the Watukosek fault system. From this volcanic complex originates the Watukosek fault system that was reactivated by the M6.3 earthquake in 2006 and is still periodically reactivated by the frequent seismicity. To date Lusi is still active and erupting gas, water, mud and clasts. Gas and water data show that the Lusi plumbing system is connected with the neighbouring Arjuno-Welirang volcanic complex. This makes the Lusi eruption a "sedimentary hosted geothermal system". To verify and characterise the occurrence of seismic activity and how this perturbs the connected Watukosek fault, the Arjuno-Welirang volcanic system and the ongoing Lusi eruption, we deployed 30 seismic stations (short-period and broadband) in this region of the East Java basin. The seismic stations are more densely distributed around LUSI and the Watukosek fault zone that stretches between Lusi and the Arjuno Welirang (AW) complex. Fewer stations are positioned around the volcanic arc. Our study sheds light on the seismic activity along the Watukosek fault system and describes the waveforms associated to the geysering activity of Lusi. The initial network aims to locate small event that may not be captured by the Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG) seismic network and it will be crucial to design the second phase of the seismic experiment that will consist of a local earthquake tomography of the Lusi-Arjuno Welirang region and temporal variations of vp/vs ratios. Such variations will then be ideally related to

  15. Apollo 14 and 16 Active Seismic Experiments, and Apollo 17 Lunar Seismic Profiling

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Seismic refraction experiments were conducted on the moon by Apollo astronauts during missions 14, 16, and 17. Seismic velocities of 104, 108, 92, 114 and 100 m/sec were inferred for the lunar regolith at the Apollo 12, 14, 15, 16, and 17 landing sites, respectively. These data indicate that fragmentation and comminution caused by meteoroid impacts has produced a layer of remarkably uniform seismic properties moonwide. Brecciation and high porosity are the probable causes of the very low velocities observed in the lunar regolith. Apollo 17 seismic data revealed that the seismic velocity increases very rapidly with depth to 4.7 km/sec at a depth of 1.4 km. Such a large velocity change is suggestive of compositional and textural changes and is compatible with a model of fractured basaltic flows overlying anorthositic breccias. 'Thermal' moonquakes were also detected at the Apollo 17 site, becoming increasingly frequent after sunrise and reaching a maximum at sunset. The source of these quakes could possibly be landsliding.

  16. Young Urban African American Adolescents' Experience of Discretionary Time Activities

    ERIC Educational Resources Information Center

    Bohnert, Amy M.; Richards, Maryse H.; Kolmodin, Karen E.; Lakin, Brittany L.

    2008-01-01

    This cross-sectional study examined the daily discretionary time experiences of 246 (107 boys, 139 girls) fifth through eighth grade urban African American adolescents using the Experience Sampling Method. Relations between the types of activities (i.e., active structured, active unstructured, passive unstructured) engaged in during discretionary…

  17. Near-field monitoring of seismic source behavior at South African deep gold mines

    NASA Astrophysics Data System (ADS)

    Ogasawara, H.; Nakatani, M.; Iio, Y.; Ishii, H.; Yamada, T.; Naoi, M.; Yasutake, G.; Kawakata, H.; Yamamoto, A.; Yamauchi, T.; Nakao, S.; Yabe, Y.; Otsuki, K.; Satoh, T.; Kato, A.; Shinya, Y.; Nagata, K.; Kuwano, O.; Igarashi, T.; Miyake, H.; Ide, S.; van Aswegen, G.; Mendecki, A.; Ward, T.; SeeSA Research Group

    2007-12-01

    We introduce our SeeSA projects, as important as dense array monitoring According to a mining plan and a geological map detailing locations of faults or weakness, we can anticipate potential M > 2 seismic sources at depths of 2.0 - 3.6 km at South African gold mines. At such potential sources, we have installed instruments prior to an onset of irreversible process to monitor earthquake generation process. From the previous projects for periods of from a year to a few years, the possible widest dynamic range and resolution have revealed the finest detail of the process since 1995 in cooperation with ISS International Ltd and South African gold mines (Mponeng, Bambanani, Tau Tona, Buffelsfontein GM, and ERPM), Wits Univ., Geohydroseis CC., Seismogen CC., OHMS CC., GFZ, GMuG, CSIR. The talk summarizes examples of our successful monitoring and introduces some on-going projects. Highlighted are the following. Yamada et al. [05, 07] demonstrated that mine tremors have rupture process as complex as natural larger earthquakes and the scale dependency of rupture parameters is similar to that for natural larger earthquakes. We successfully recorded strain accumulations larger than 100 micro strain, followed by several hundreds of seismic events (-1 < M < 3; distance < ~ 250 m). The seismicity within about 100m from strainmeters caused frequent, seismic strain-steps; the largest recorded was greater than 100 micro strain by an M2.5 earthquake at a distance within ~100 m. One of the most important results were that no detectable accelerating precursors preceded strain-steps associated with several hundreds of the earthquakes (- 1 < M < 3) catalogued by mine's seismic networks (hereinafter Catalogued E/Q; Takeuchi 05), while significant post-seismic drifts followed some strain-steps by Catalogued E/Qs. Frequently observed were episodic strain changes with durations of much slower than strain-steps associated with the Catalogued E/Qs [Naoi et al. 06]. Striking were some examples

  18. Results from the apollo-12 passive seismic experiment

    USGS Publications Warehouse

    Latham, G.

    1971-01-01

    The objective of the passive seismic experiment is to measure vibrations of the lunar surface produced by all natural and artificial sources of seismic energy and to use these data to deduce the internal structure and composition of the moon, the nature of forces which may cause deformation of the moon and moonquakes, and the numbers and masses of meteoroids striking the lunar surface. The ALSEP* seismometers can magnify lunar surface vibrations 10 million times. No instrument can operate on earth with this sensitivity, because weather and man produce too much seismic noise. To obtain answers to the above questions, seismic data must be combined with data from laboratory measurements of the physical and chemical properties of surface rocks, and many other geophyiscal and geochemical measurements. Thus far, we have had the opportunity to record data from two lunar seismic stations which were installed by the astronauts during Apollo misions  and 12. The combined recording time from the stations is presently over 12 months, but there was no overlap to permit recording of the same event at two stations. 

  19. The deep seismic structure of the Ethiopia/Afar hotspot and the African superplume

    NASA Astrophysics Data System (ADS)

    Hansen, Samantha E.; Nyblade, Andrew A.

    2013-07-01

    The Ethiopia/Afar hotspot has been frequently explained as an upper mantle continuation of the African superplume, with anomalous material in the lower mantle under southern Africa, rising through the transition zone beneath eastern Africa. However, the significantly larger amplitude low velocity anomaly in the upper mantle beneath Ethiopia/Afar, compared to the anomalies beneath neighboring regions, has led to questions about whether or not along-strike differences in the seismic structure beneath eastern Africa and western Arabia are consistent with the superplume interpretation. Here we present a new P-wave model of the hotspot's deep structure and use it to evaluate the superplume model. At shallow (< ˜400 km) depths, the slowest velocities are centered beneath the Main Ethiopian Rift, and we attribute these low velocities to decompression melting beneath young, thin lithosphere. At deeper depths, the low velocity structure trends to the northeast, and the locus of the low velocity anomaly is found beneath Afar. The northeast-trending structure with depth is best modeled by northeastward flow of warm superplume material beneath eastern Africa. The combined effects of shallow decompression melting and northeastward flow of superplume material explain why upper mantle velocities beneath Ethiopia/Afar are significantly slower than those beneath neighboring East Africa and western Arabia. The superplume interpretation can thus explain the deep seismic structure of the hotspot if the effects of both decompression melting and mantle flow are considered.

  20. African American Women's Sexual Objectification Experiences: A Qualitative Study

    ERIC Educational Resources Information Center

    Watson, Laurel B.; Robinson, Dawn; Dispenza, Franco; Nazari, Negar

    2012-01-01

    The purpose of our study was to investigate African American women's experiences with sexual objectification. Utilizing grounded theory methodology as well as Black feminist thought and objectification theory as the research lenses, the results of this study uncovered how racist, sexist, and classist ideologies contributed to sexual…

  1. Financing vaccinations - the South African experience.

    PubMed

    Blecher, Mark S; Meheus, Filip; Kollipara, Aparna; Hecht, Robert; Cameron, Neil A; Pillay, Yogan; Hanna, Luisa

    2012-09-01

    South Africa provides a useful country case study for financing vaccinations. It has been an early adopter of new vaccinations and has financed these almost exclusively from domestic resources, largely through general taxation. National vaccination policy is determined by the Department of Health, based on advice from a national advisory group on immunisation. Standard health economic criteria of effectiveness, cost-effectiveness, affordability and burden of disease are used to assess whether new vaccinations should be introduced. Global guidelines and the advice of local and international experts are also helpful in making the determination to introduce new vaccines. In terms of recent decisions to introduce new vaccines against pneumococcal disease and rotavirus diarrhoea in children, the evidence has proved unequivocal. Universal rollout has been implemented even though this has led to a fivefold increase in national spending on vaccines. The total cost to government remains below 1-1.5% of public expenditures for health, which is viewed by the South African authorities as affordable and necessary given the number of lives saved and morbidity averted. To manage the rapid increase in domestic spending, efforts have been made to scale up coverage over several years, give greater attention to negotiating price reductions and, in some cases, obtain initial donations or frontloaded deliveries to facilitate earlier universal rollout. There has been strong support from a wide range of stakeholders for the early introduction of new generation vaccines. PMID:22939027

  2. African-American Women's Perceptions and Experiences About Breastfeeding.

    PubMed

    Obeng, Cecilia S; Emetu, Roberta E; Curtis, Terry J

    2015-01-01

    There are health benefits to breastfeeding for both mothers and their children. The preventive health effects of breastfeeding continue into adulthood, lowering rate of various chronic illnesses. African-American women, especially of lower socioeconomic status, are less likely to breastfeed in comparison to their racial and ethnic counterparts. The purpose of this study is to explore how African-American women experience breastfeeding in the early stages of postpartum care. Two focus groups (N = 20, 10 in each group) were conducted with African-American mothers. Results revealed that participants felt that there were health benefits to breastfeeding, and organizations such as Women, Infants, and Children (WIC) provided support. However, participants stated that lack of information, negative perceptions, and unforeseen circumstances were barriers to breastfeeding. This study proposes support and interventions for this group to increase breastfeeding among this population. PMID:26734597

  3. Free online seismic data from a sand tank experiment

    NASA Astrophysics Data System (ADS)

    Lorenzo, J. M.; Smolkin, D.; White, C.; Chollett, S.; Sun, T.

    2012-12-01

    Theoretical fluid flow models are used regularly to predict and analyze porous media flow but require verification against natural systems. Seismic monitoring in a controlled laboratory setting at a nominal scale of 1:1000 in the acoustic frequency range can help improve fluid flow models as well as elasto-granular models for uncompacted, saturated-unsaturated soils. A mid-scale sand tank allows for many highly repeatable, yet flexible, experimental configurations with different material compositions and pump rates while still capturing phenomena such as patchy saturation, flow fingering, or layering. The tank (~6 x 9 x 0.44 m) contains a heterogeneous sand pack (1.52-1.7 phi). In a set of eight experiments the water table is raised inside the sand body at increments of ~0.05 m. Seismic events (vertical component) are recorded by a pseudo-walkaway 64-channel accelerometer array (20 Hz-20 kHz), at 78 kS/s, in 100- scan stacks so as to optimize signal-to-noise. Three screened well sites monitor water depth (+/- 3 mm) inside the sand body. Data sets comprise SEG-Y formatted files (seismic) and are publicly downloadable from the internet (http://github.com/cageo/Lorenzo-2012), in order to allow comparisons of different seismic and fluid flow analyses. The capillary fringe does not appear to completely saturate, as expected, because the interpreted compressional-wave velocity values remain so low (< 210 m/s). Even the highest water levels there is no large seismic impedance contrast across the top of the water table to generate a clear reflector. Preliminary results indicate an immediate need for several additional experiments whose data sets will be added to the online database. Future benchmark data sets will grow with a control data set to show conditions in the sand body before water levels rise, and a surface 3D data set. In later experiments, buried sensors will help reduce seismic attenuation effects and in-situ saturation sensors will provide calibration values.

  4. African Mask-Making Workshop: Professional Development Experiences of Diverse Participants

    ERIC Educational Resources Information Center

    Rule, Audrey C.; Montgomery, Sarah E.; Kirkland-Holmes, Gloria; Watson, Dwight C.; Ayesiga, Yvonne

    2015-01-01

    Diverse education professionals learned about African cultures in a workshop experience by making African masks using authentic symbolism. Analysis of reflections to evaluate the workshop for applicability to participants with and without African heritage showed that both groups expanded their cultural knowledge of traditional African ethnic…

  5. Deep crustal structure of the North-West African margin from combined wide-angle and reflection seismic data (MIRROR seismic survey)

    NASA Astrophysics Data System (ADS)

    Biari, Y.; Klingelhoefer, F.; Sahabi, M.; Aslanian, D.; Schnurle, P.; Berglar, K.; Moulin, M.; Mehdi, K.; Graindorge, D.; Evain, M.; Benabdellouahed, M.; Reichert, C.

    2015-08-01

    The structure of the Moroccan and Nova Scotia conjugate rifted margins is of key importance for understanding the Mesozoic break-up and evolution of the northern central Atlantic Ocean basin. Seven combined multichannel reflection (MCS) and wide-angle seismic (OBS) data profiles were acquired along the Atlantic Moroccan margin between the latitudes of 31.5° and 33° N during the MIRROR seismic survey in 2011, in order to image the transition from continental to oceanic crust, to study the variation in crustal structure, and to characterize the crust under the West African Coast Magnetic Anomaly (WACMA). The data were modeled using a forward modeling approach. The final models image crustal thinning from 36 km thickness below the continent to approximately 8 km in the oceanic domain. A 100 km wide zone characterized by rough basement topography and high seismic velocities up to 7.4 km/s in the lower crust is observed westward of the West African Coast Magnetic Anomaly. No basin underlain by continental crust has been imaged in this region, as has been identified north of our study area. Comparison to the conjugate Nova Scotian margin shows a similar continental crustal thickness and layer geometry, and the existence of exhumed and serpentinized upper mantle material on the Canadian side only. The oceanic crustal thickness is lower on the Canadian margin.

  6. Characterization of rockfalls from seismic signal: Insights from laboratory experiments

    NASA Astrophysics Data System (ADS)

    Farin, Maxime; Mangeney, Anne; Toussaint, Renaud; Rosny, Julien de; Shapiro, Nikolai; Dewez, Thomas; Hibert, Clément; Mathon, Christian; Sedan, Olivier; Berger, Frédéric

    2015-10-01

    The seismic signals generated by rockfalls can provide information on their dynamics and location. However, the lack of field observations makes it difficult to establish clear relationships between the characteristics of the signal and the source. In this study, scaling laws are derived from analytical impact models to relate the mass and the speed of an individual impactor to the radiated elastic energy and the frequency content of the emitted seismic signal. It appears that the radiated elastic energy and frequencies decrease when the impact is viscoelastic or elastoplastic compared to the case of an elastic impact. The scaling laws are validated with laboratory experiments of impacts of beads and gravels on smooth thin plates and rough thick blocks. Regardless of the involved materials, the masses and speeds of the impactors are retrieved from seismic measurements within a factor of 3. A quantitative energy budget of the impacts is established. On smooth thin plates, the lost energy is either radiated in elastic waves or dissipated in viscoelasticity when the impactor is large or small with respect to the plate thickness, respectively. In contrast, on rough thick blocks, the elastic energy radiation represents less than 5% of the lost energy. Most of the energy is lost in plastic deformation or rotation modes of the bead owing to surface roughness. Finally, we estimate the elastic energy radiated during field scale rockfalls experiments. This energy is shown to be proportional to the boulder mass, in agreement with the theoretical scaling laws.

  7. IRIS Controlled Source Seismic Experiments: Continental Structure, Instrumentation, and Education

    NASA Astrophysics Data System (ADS)

    Mooney, W. D.; Keller, G. R.

    2004-12-01

    The controlled-source seismology program of IRIS/PASSCAL has made major contributions to the study of continental structure and evolution. It has also undergone major developments in seismic instrumentation. The first PASSCAL experiments (1984/85) targeted the Basin and Range Province and the Ouachita orogenic belt. The Basin and Range study provided remarkably clear images of this thin, highly-extended crust, while the Ouachita experiment tested competing hypotheses for the deep structure of this Paleozoic orogen. However, both of these projects were limited by a lack of seismic instruments. The situation improved in the late 1980's with the benefit of a mixed array of 600 seismic recorders from the USGS, Stanford, and the Geological Survey of Canada. The resolution achieved with these instruments was revolutionary. Results include the imaging of such remarkable features as crustal-scale duplexes in the Brooks Range compressional orogen of northern Alaska, and of crustal "core complexes" in the extended crust of southwest Arizona. The 3-channel PASSCAL Jr. instrument was developed, leading to experiments in which ˜1000 instruments were deployed, including three-component recording. This complex mix of instruments served the community well for several years, but required large, complex instrument centers and lots of technical support. With input from PASSCAL and the international community, a newly designed, compact instrument (the Texan) was finalized in the spring of 1998, and the first 200 instruments was delivered to the Univ. of Texas-El Paso in late 1998. The present instrument pool of Texans exceeds 1,400 and these have been used on such projects as the high-resolution imaging of the Los Angeles and San Fernando basins (LARSE I and II experiments), where active thrust faults have been imaged. Controlled-source seismic experiments are now very numerous. During calendar year 2004 alone, portable Texan instruments have traveled from Venezuela to Denmark

  8. Full seismic waveform inversion of the African crust and Mantle - Initial Results

    NASA Astrophysics Data System (ADS)

    Afanasiev, Michael; Ermert, Laura; Staring, Myrna; Trampert, Jeannot; Fichtner, Andreas

    2016-04-01

    We report on the progress of a continental-scale full-waveform inversion (FWI) of Africa. From a geodynamic perspective, Africa presents an especially interesting case. This interest stems from the presence of several anomalous features such as a triple junction in the Afar region, a broad region of high topography to the south, and several smaller surface expressions such as the Cameroon Volcanic Line and Congo Basin. The mechanisms behind these anomalies are not fully clear, and debate on their origin spans causative mechanisms from isostatic forcing, to the influence of localized asthenospheric upwelling, to the presence of deep mantle plumes. As well, the connection of these features to the African LLSVP is uncertain. Tomographic images of Africa present unique challenges due to uneven station coverage: while tectonically active areas such as the Afar rift are well sampled, much of the continent exhibits a severe dearth of seismic stations. As well, while mostly surrounded by tectonically active spreading plate boundaries (a fact which contributes to the difficulties in explaining the South's high topography), sizeable seismic events (M > 5) in the continent's interior are relatively rare. To deal with these issues, we present a combined earthquake and ambient noise full-waveform inversion of Africa. The noise component serves to boost near-surface sensitivity, and aids in mitigating issues related to the sparse source / station coverage. The earthquake component, which includes local and teleseismic sources, aims to better resolve deeper structure. This component also has the added benefit of being especially useful in the search for mantle plumes: synthetic tests have shown that the subtle scattering of elastic waves off mantle plumes makes the plumes an ideal target for FWI [1]. We hope that this new model presents a fresh high-resolution image of sub-African geodynamic structure, and helps advance the debate regarding the causative mechanisms of its surface

  9. 3D Seismic Reflection Experiment over the Galicia Deep Basin

    NASA Astrophysics Data System (ADS)

    Sawyer, D. S.; Jordan, B.; Reston, T. J.; Minshull, T. A.; Klaeschen, D.; Ranero, C.; Shillington, D. J.; Morgan, J. K.

    2014-12-01

    In June thru September, 2013, a 3D reflection and a long offset seismic experiment were conducted at the Galicia rifted margin by investigators from the US, UK, Germany, and Spain. The 3D multichannel experiment covered 64 km by 20 km (1280 km2), using the RV Marcus Langseth. Four streamers 6 km long were deployed at 12.5 m hydrophone channel spacing. The streamers were 200 m apart. Two airgun arrays, each 3300 cu in, were fired alternately every 37.5 m, to collectively yield a 400 m wide sail line consisting of 8 CMP lines at 50 m spacing. The long offset seismic experiment included 72 short period OBS's deployed below the 3D reflection survey box. Most of the instruments recorded all the shots from the airgun array shots. The 3D seismic box covered a variety of geologic features. The Peridotite Ridge (PR), is associated with the exhumation of upper mantle rocks to the seafloor during the final stage of the continental separation between the Galicia Bank and the Grand Banks of Newfoundland. The S reflector is present below most of the continental blocks under the deep Galicia basin. S is interpreted to be a low-angle detachment fault formed late in the rifting process, and a number of rotated fault block basins and ranges containing pre and syn-rift sediments. Initial observations from stacked 3D seismic data, and samples of 2D pre-stack time migrated (PSTM) 3D seismic data show that the PR is elevated above the present seafloor in the South and not exposed through the seafloor in the North. The relative smoothness of the PR surface for the entire 20 km N-S contrasts with the more complex, shorter wavelength, faulting of the continental crustal blocks to the east. The PR does not seem to show offsets or any apparent internal structure. The PSTM dip lines show substantial improvement for the structures in the deep sedimentary basin East of the PR. These seem to extend the S reflector somewhat farther to the West. The migrated data show a substantial network of

  10. Seismic tomography Technology for the Water Infiltration Experiment

    SciTech Connect

    J. Descour

    2001-04-30

    NSA Engineering, Inc., conducted seismic tomography surveys in Niche No.3 in the Exploratory Studies Facility (ESF), Yucca Mountain, Nevada, and Alcove No.8 in the Enhanced Characterization of the Repository Block (ECRB) cross drift as part of the Infiltration Experiment being conducted in Niche No.3. NSA Engineering is a direct support contractor to the Yucca Mountain Project. This report documents the work performed from August 14 through 30, 2000, prior to the beginning of the infiltration experiment. The objective of the seismic tomography survey was to investigate the flow path of water between access drifts and more specifically to (Kramer 2000): (1) Conduct a baseline seismic tomography survey prior to the infiltration experiment; (2) Produce 2-D and 3-D tomographic images of the rock volume between Alcove No.8 and Niche No.3; (3) Correlate tomography results with published structural and lithological features, and with other geophysical data such as ground penetrating radar (GPR); and (4) Results of this survey will form a baseline with which to compare subsequent changes to the rock mass. These changes may be as a result of the water infiltration tests that could be conducted in Alcove No.8 in 2001. The scope of this reported work is to use the velocity tomograms to: (a) assess the structures and lithologic features within the surveyed area and/or volume between the two access drifts; and (b) provide information on the structural state of the rock mass as inferred by the velocity signatures of the rock prior to the beginning of the infiltration experiment.

  11. Looking for seismic scatterers: summer research experience for undergraduate students

    NASA Astrophysics Data System (ADS)

    Gerasimenko, I.; Bagchi, S.; Toteva, T.; Peng, Z.

    2008-12-01

    This project was part of collaboration between Randolph College (VA) and Georgia Institute of Technology (GA). It was designed as summer research experience for undergraduate students. The duration of the project was eight weeks. The aim of this study was to search for fault zone scatterers in the Parkfield section of the San Andreas Fault, and examine the presence or absence of physical changes in the scattering intensity before and after the 2004 M6 Parkfield earthquake. The two students visited Georgia Tech for a week and were trained to manipulate seismic data in Seismic Analysis Code (SAC) format. They assembled a data base of over a thousand events that occurred before and after the M6 earthquake and were recorded by the USGS Parkfield, California, dense seismograph array (UPSAR). They manually picked the arrivals for the P and S waves. Additional signal processing such as frequency filtering and semblance analysis were applied to the records in search for isolated scatterers in the seismic coda. While the eight-week-long research was not enough for the students to complete their project, it was certainly enough to sparkle excitement for conducting seismological research. Currently both students are enrolled in a research topics class and continue to work on this project. Their past and future work will be presented at the meeting.

  12. Characterisation of rockfalls from seismic signal: insights from laboratory experiments

    NASA Astrophysics Data System (ADS)

    Farin, Maxime; Mangeney, Anne; Toussaint, Renaud; de Rosny, Julien; Shapiro, Nikolai; Dewez, Thomas; Hibert, Clément; Mathon, Christian; Sedan, Olivier; Berger, Frédéric

    2015-04-01

    Rockfalls, debris flows and rock avalanches represent a major natural hazard for the population in mountainous, volcanic and coastal areas but their direct observation on the field is very difficult. Recent field studies showed that gravitational instabilities can be detected, localized and characterized thanks to the seismic signal they generate. Therefore, a burning challenge for risks assessment related to these events is to obtain quantiative informations on the characteristics of the rockfalls (mass, speed, extension,...) from the properties of the signal (seismic energy, frequencies,...). Using a theoretical model of viscoelastic impact of a sphere on a plane, we develop analytical scaling laws relating the energy radiated in elastic waves, the energy dissipated in viscoelasticity during the impact and the frequencies of the generated seismic signal to the mass m and the impact speed V z of the sphere and to the elastic parameters of the involved materials. The radiated elastic energy is shown to vary as m5/3V z11/5 on plates and as mV z13/5 on blocks, regardless of the elastic parameters. The energy dissipated in viscoelasticity does not depend on the support thickness and varies as m2/3V z11/5. The mean frequency of the generated signal is inversely proportional to the impact duration. Then, we conduct simple laboratory experiments that consist in dropping spherical beads of different size and materials and small gravels on thin plates of glass and PMMA and rock blocks. In the experiments, piezoelectric accelerometers are used to record the signals in a wide frequency range: 1 Hz to 56 kHz. The experiments are also monitored optically using fast cameras. The elastic energy emitted by an impact on the supports is first quantitatively estimated and compared to the potential energy of fall and to the potential energy change during the shock. We observe a quantitative agreement between experimental data and the analytical scaling laws, even when we use small

  13. Older African American Women’s Lived Experiences with Depression

    PubMed Central

    Ward, Earlise C.; Mengesha, Maigenete; Issa, Fathiya

    2014-01-01

    Little is known about older African American women’s lived experiences with depression. What does depression mean to this group? What are they doing about their depression? Unfortunately, these questions are unanswered. This study examined older African American women’s lived experiences with depression and coping behaviours. The common sense model provided the theoretical framework for present study. Thirteen community-dwelling African American women aged 60 and older (M =71 years) participated. Using qualitative phenomenological data analysis, results showed the women held beliefs about factors that can cause depression including experiences of trauma, poverty, and disempowerment. Results also indicated the women believed that depression is a normal reaction to life circumstances and did not see the need to seek professional treatment for depression. They coped by use of culturally-sanctioned behaviours including religious practices and resilience. It appears these women’s beliefs about depression and use of culturally-sanctioned coping behaviours might potentially be a barrier to seeking professional mental health care, which could result in missed opportunities for early diagnosis and treatment of depression among this group. Implications for research, educational and clinical interventions are discussed. PMID:23742034

  14. Results of a seismic forecasting experiment for the Kamchatka region

    NASA Astrophysics Data System (ADS)

    Doda, L. N.; Natyaganov, V. L.; Shopin, S. A.

    2016-08-01

    The integral results of a seismic forecasting experiment for the powerful M > 7 earthquakes in the Kamchatka region are presented. According to the empirical scheme of the short-term earthquake prediction, since 2002 all officially recorded forecasts, including five deep-focus earthquakes in the Sea of Okhotsk, have been predicted without missing events. The specific character of the features of the earthquake preparation and the annular cloud structures that began to be observed in satellite images near the coast of Japan at the boundary of the Okhotsk plate are analyzed.

  15. The Meaning of African American College Women's Experiences Attending a Predominantly White Institution: A Phenomenological Study

    ERIC Educational Resources Information Center

    Hannon, Christine R.; Woodside, Marianne; Pollard, Brittany L.; Roman, Jorge

    2016-01-01

    Because both race and gender are important to the development of African American women, student affairs professionals need to understand the unique experiences of African American women within the context of the college environment. In this phenomenological study, we examined African American women's lived experiences as college students at a…

  16. Seismic structure of the crust and lithospheric mantle of the southern African cratonic region

    NASA Astrophysics Data System (ADS)

    Youssof, M.; Thybo, H.; Artemieva, I. M.; Levander, A.

    2013-12-01

    We present a new seismic model for the structure of the crust and lithospheric mantle in southern Africa constrained by a joint study of seismic receiver functions and finite-frequency tomography, using the high-quality data from the South Africa Seismic Experiment (SASE). A) The crust has a highly heterogeneous structure with short wavelength variations in (i) thickness, (ii) composition (reflected in Vp/Vs-ratio calculated for all SASE stations), and (iii) Moho sharpness (which is quantified and mapped for the entire region) (Youssof et al., Tectonophysics, in review). By mapping these three parameters, we distinguish ~20 crustal blocks that do not everywhere coincide with surface tectonic features. Our RFs also demonstrate strong azimuthal anisotropy in the crust, with a typical crustal contribution to the total S-wave splitting of at least 30%. Spatial correlation of the S-wave polarization directions of crustal and mantle anisotropy indicates (i) the presence of three distinct Archean lithospheric terranes and (ii) coupling between the crust and lithospheric mantle in most of the study area, with a strong decoupling in western Kaapvaal where the crustal anisotropy is strongest. The similarity of anisotropy directions in the crust and mantle beneath much of the Kaapvaal craton indicates that (a) the seismic anisotropy originates at the time of cratonization and (b) the observed correspondence between the present direction of absolute plate motion (APM) and lithosphere anisotropy is coincidental. B) A new 3D high-resolution seismic model of the lithospheric mantle has been determined from finite frequency tomographic inversions of teleseismic P- and S- body wave data. The two velocity models are very similar in structure, but differ in the relative P- and S-wave velocity anomalies. We find that: 1) the fast lithospheric keels extends very deep, perhaps to depths of 300-350 km and 250 km beneath the Kaapvaal and Zimbabwe cratons, respectively, and 2) the Archean

  17. Seismic amplification within the Seattle Basin, Washington State: Insights from SHIPS seismic tomography experiments

    USGS Publications Warehouse

    Snelson, C.M.; Brocher, T.M.; Miller, K.C.; Pratt, T.L.; Trehu, A.M.

    2007-01-01

    Recent observations indicate that the Seattle sedimentary basin, underlying Seattle and other urban centers in the Puget Lowland, Washington, amplifies long-period (1-5 sec) weak ground motions by factors of 10 or more. We computed east-trending P- and S-wave velocity models across the Seattle basin from Seismic Hazard Investigations of Puget Sound (SHIPS) experiments to better characterize the seismic hazard the basin poses. The 3D tomographic models, which resolve features to a depth of 10 km, for the first time define the P- and S-wave velocity structure of the eastern end of the basin. The basin, which contains sedimentary rocks of Eocene to Holocene, is broadly symmetric in east-west section and reaches a maximum thickness of 6 km along our profile beneath north Seattle. A comparison of our velocity model with coincident amplification curves for weak ground motions produced by the 1999 Chi-Chi earthquake suggests that the distribution of Quaternary deposits and reduced velocity gradients in the upper part of the basement east of Seattle have significance in forecasting variations in seismic-wave amplification across the basin. Specifically, eastward increases in the amplification of 0.2- to 5-Hz energy correlate with locally thicker unconsolidated deposits and a change from Crescent Formation basement to pre-Tertiary Cascadia basement. These models define the extent of the Seattle basin, the Seattle fault, and the geometry of the basement contact, giving insight into the tectonic evolution of the Seattle basin and its influence on ground shaking.

  18. 3D Seismic Reflection Experiment Over the Galicia Deep Basin

    NASA Astrophysics Data System (ADS)

    Sawyer, Dale; Jordan, Brian; Tesi Sanjurjo, Mari; Alexanian, Ara; Morgan, Julia; Shillington, Donna; Reston, Timothy; Minshull, Timothy; Klaeschen, Dirk; Ranero, César

    2014-05-01

    In June thru September, 2013, a 3D reflection and a long offset seismic experiment were conducted at the Galicia rifted margin by investigators from the US, UK, Germany, and Spain. The 3D multichannel experiment covered 64 km by 20 km (1280 km2), using the RV Marcus Langseth. Four streamers 6 km long were deployed at 12.5 m hydrophone channel spacing. The streamers were 200 m apart. Two airgun arrays, each 3300 cu in, were fired alternately every 37.5 m, to collectively yield a 400 m wide sail line consisting of 8 CMP lines at 50 m spacing. The long offset seismic experiment included 72 short period OBS's deployed below the 3D reflection survey box. Most of the instruments recorded all the shots from the airgun array shots. The 3D seismic box covered a variety of geologic features. The Peridotite Ridge (PR), is associated with the exhumation of upper mantle rocks to the seafloor during the final stage of the continental separation between the Galicia Bank and the Grand Banks of Newfoundland. The S reflector is present below most of the continental blocks under the deep Galicia basin. S is interpreted to be a low-angle detachment fault formed late in the rifting process, and a number of rotated fault block basins and ranges containing pre and syn-rift sediments. Initial observations from stacked, but not yet migrated, 3D seismic data show that the PR is elevated above the present seafloor in the South and not exposed through the seafloor in the North. The relative smoothness of the PR surface for the entire 20 km N-S contrasts with the more complex, shorter wavelength, faulting of the continental crustal blocks to the east. The PR does not seem to show offsets or any apparent internal structure. However, migration will be required to see internal structure of the PR. Between the PR and the western most rifted continental crustal blocks, is a sedimentary basin about as wide as the PR and very different from the sedimentary basins bounded by the continental crustal

  19. The KRISP 90 seismic experiment-a technical review

    USGS Publications Warehouse

    Prodehl, C.; Mechie, J.; Achauer, U.; Keller, Gordon R.; Khan, M.A.; Mooney, W.D.; Gaciri, S.J.; Obel, J.D.

    1994-01-01

    On the basis of a preliminary experiment in 1985 (KRISP 85), a seismic refraction/wide-angle reflection survey and a teleseismic tomography experiment were jointly undertaken to study the lithospheric structure of the Kenya rift down to depths of greater than 200 km. This report serves as an introduction to a series of subsequent papers and will focus on the technical description of the seismic surveys of the main KRISP 90 effort. The seismic refraction/wide-angle reflection survey was carried out in a 4-week period in January and February 1990. It consisted of three profiles: one extending along the rift valley from Lake Turkana to Lake Magadi, one crossing the rift at Lake Baringo, and one located on the eastern flank of the rift proper. A total of 206 mobile vertical-component seismographs, with an average station interval of about 2 km, recorded the energy of underwater and borehole explosions to distances of up to about 550 km. During the teleseismic survey an array of 65 seismographs was deployed to record teleseismic, regional and local events for a period of about 7 months from October 1989 to April 1990. The elliptical array spanned the central portion of the rift, with Nakuru at its center, and covered an area about 300 ?? 200 km, with an average station spacing of 10-30 km. Major scientific goals of the project were to reveal the detailed crustal and upper-mantle structure under the Kenya rift, to study the relationship between deep crustal and mantle structure and the development of sedimentary basins and volcanic features within the rift, to understand the role of the Kenya rift within the Afro-Arabian rift system, and to answer fundamental questions such as the mode and mechanism of continental rifting. ?? 1994.

  20. Experiences of HIV-positive African-American and African Caribbean childbearing women: a qualitative study.

    PubMed

    Njie-Carr, Veronica; Sharps, Phyllis; Campbell, Doris; Callwood, Gloria

    2012-07-01

    This qualitative study examined the experiences of HIV-positive African-American and African Caribbean childbearing women related to decisions about HIV testing, status disclosure, adhering to treatment, decisions about childbearing, and experiences in violent intimate relationships. Twenty-three women completed a 60-minute in-depth interview. Six themes emerged: perceived vulnerability to HIV infection; feelings about getting tested for HIV; knowledge, attitudes, and behaviors after HIV diagnosis; disclosure of HIV status; living with HIV (positivity, strength, and prayer); and, experiences with physical and sexual violence. Three women (13%) reported perinatal abuse and 10 women (n = 23, 43.4%) reported lifetime abuse. Positive experiences and resilience were gained from faith and prayer. Most important to the women were the perceived benefits of protecting the health of their baby. Findings suggest that policies supporting early identification of HIV-positive childbearing women are critical in order to provide counseling and education in forming their decisions for safety precautions in violent intimate partner relationships.

  1. Seismic experiment paves way for long-term seafloor observatories

    NASA Astrophysics Data System (ADS)

    Stakes, Debra S.; Romanowicz, Barbara; Montagner, Jean-Paul; Tarits, Pascal; Karczewski, Jean-Francois; Etchemendy, Steve; Dawe, Craig; Neuhauser, Doug; McGill, Paul; Koenig, Jean Claude; Savary, Jean; Begnaud, Mike; Pasyanos, Mike

    The Monterey Bay Ocean Bottom International Seismic Experiment (MOISE) has successfully deployed a suite of geophysical and oceanographic instrument packages on the ocean floor using the Monterey Bay Aquarium Research Institute's (MBARI) Ventana, a tethered Remotely Operated Vehicle (ROV).The goal of this international cooperative experiment is to advance the global Seafloor Observatory effort by developing a prototype suite of instruments and installing them on the western side of the San Andreas fault system offshore of central California. The centerpiece of the instrument suite was a digital broadband seismometer package partially buried within the sediment-covered floor of Monterey Bay, 40 km offshore and 10 km west of the San Gregorio fault at a depth of 1015 m (Figure 1).

  2. The BOrborema Deep Electromagnetic and Seismic (BODES) Experiment

    NASA Astrophysics Data System (ADS)

    Julià, J.; Garcia, X.; Medeiros, W. E.; Farias do Nascimento, A.

    2015-12-01

    The Borborema Province of NE Brazil is a large Precambrian domain of the Brazilian shield located in the Northeasternmost corner of South America. It is bounded by the Parnaíba basin to the West and by the São Francisco craton to the South. Its structuration in the Precambrian has been related to compressional processes during the Brasiliano-Pan African orogeny (600-550 Ma). In the Mesozoic, extensional stresses eventually leading to continental breakup, left a number of aborted rift basins within the Province. After continental breakup, the evolution of the Province was marked by episodes of uplift, which might have been coeval with episodes of Cenozoic volcanism. The most prominent expression of those uplift processes is the Borborema Plateau, an elliptically shaped topographic feature in the eastern half of the Province with maximum elevations of ~1200 m. The origin of uplift in the Plateau has been the focus of a number of multi-institutional and multi-disciplinary studies in the past few years, which have imaged the deep structure of the eastern Province with unprecedented detail. The origin of uplift in the western Province, which includes a superb example of basin inversion demonstrated by the ~1000 km elevations of the Chapada do Araripe, however, has been seldom investigated. With the goal of investigating the deep structure of the western Province, a temporary network of 10 collocated seismic and magnetotelluric stations was deployed in the region. The collocated stations were arranged in an approximately NS direction, with an interspation spacing of ~70 km and spanning a total length of ~600 km. The seismic stations consisted of broadband sensors (RefTek 151B-120 "Observer") sampling at 100 Hz and were deployed in January 2015; the MT stations consisted of long-period magnetotelluric (LEMI) systems, sampling at 1 Hz and 4 Hz, and were deployed in April 2015 for a period of ~2 weeks. Preliminary results based on teleseismic P-wave receiver functions

  3. The experiences of African American graduate students: A cultural transition

    NASA Astrophysics Data System (ADS)

    Joseph, Joretta

    Historically Black Colleges and Universities (HBCU) have long been an intellectual resource for the African American community. HBCUs have provided and continue to provide an educational pathway for many Black students, particularly women who seek graduate and advanced degrees. However, despite the overwhelmingly positive presence of HBCU in the African American community, the academic training of students who graduate from HBCUs may be perceived as insufficient by predominantly White graduate institutions (PWIs). As a result, African American students who are not well integrated into their respective departmental communities and cultures at PW/is are likely to leave graduate school. Thus the continuing loss of talented people, potential research, role models for society, and the next generation of African American students in the fields of math, engineering, and the sciences (STEM) create a segregated and limited university environment. Studies in the field that attempt to provide insight in to experiences of underrepresented students are ultimately beneficial. However, often such studies do not address the process of adapting to the culture of a predominantly white institution (PWI), particularly within white and male dominated fields such as mathematics and the sciences. Research has also indicated that the first two years at a predominantly white graduate institution is the crucial transitional period for students of color, and it is this transitional moment in time that is the focus of this study. I consider how students make the transition from HBCU to majority institutions, and what impact this transition has on their persistence and commitment to their discipline. The limited amount of research that does address the experiences of minority doctoral students in math and science is usually coupled with the experiences of women. However, race and gender are not linear or additive. It cannot be assumed that the same factors that effect the under representation

  4. Resiliency in Physics: The Lived Experiences of African-American Women Who Completed Doctoral Physics Programs

    ERIC Educational Resources Information Center

    Burnette, Samara Fleming

    2013-01-01

    Currently, little is known about African-American women with doctoral degrees in physics. This study examined the lived experiences of African-American women who completed doctoral programs in physics. Due to factors of race and gender, African-American women automatically enter a double-bind in science, technology, engineering, and mathematics…

  5. The Meaning of KMT (Ancient Egyptian) History for Contemporary African American Experience.

    ERIC Educational Resources Information Center

    Hilliard, Asa G., III

    1992-01-01

    Explores the history of KMT (ancient Egypt) and its importance for contemporary African-American experience. Reviews evidence that ancient Egypt was a black African population bound by history and culture to the rest of Africa. The rescue of Kemetic history can restore a sense of heritage to African Americans. (SLD)

  6. An ocean-bottom hydrophone recorder for seismic refraction experiments

    NASA Astrophysics Data System (ADS)

    Sinha, M. C.; Owen, T. R. E.; Mason, M.

    1981-06-01

    A new and inexpensive pop-up ocean-bottom hydrophone recorder has been developed for use in seismic refraction experiments. It is capable of operating in water depths of up to 4000 m and in very rugged topography, and uses an acoustic command system built by the U.K. Institute of Oceanographic Sciences for recovery. The instrument is mounted in an inexpensive cylindrical pressure case based on commercially available extruded aluminium alloy tubing, and uses glass spheres and syntactic foam for buoyancy. Hydrophone and clock signals are frequency modulated and recorded on tape cassettes, with a recording duration of three hours allowing up to 18 programmed shot windows. The prototype has made seven free descents on the Mid-Atlantic ridge and in the Gulf of Oman, and successfully recorded shots under operational conditions for the first time in September 1979. The total component cost of the prototype was £2740 (1979 prices).

  7. Factors Influencing Dating Experiences Among African American Emerging Adults

    PubMed Central

    Hall, Naomi M.; Lee, Anna K.; Witherspoon, Daphne D.

    2014-01-01

    This study examined sociocultural factors that impact dating and sexual experiences of heterosexual African American undergraduate college students attending a historically Black institution in the Southeastern United States. Specifically, mate availability and relationship involvement were analyzed to document students’ experiences, and how these influences may be associated with sexual decision making and behavior. Data from nine focus groups (N = 57) were aggregated and four subthemes were identified: competition among women, acceptability of mates, high prevalence of casual relationships, and lowered expectations for commitment. Power dynamics emerged as a contributing factor to the types of relationship involvement, sexual decision-making, and behavior among participants. The importance of prevention programs focusing on situational and cultural variables is highlighted. Additionally, implications for professionals working with emerging adults to consider the impact of the gender ratio imbalance, and perceived power distributions on perceptions of dating relationships, and sexual decision making and behavior are addressed. PMID:25530924

  8. Seismic Reflectivity Evolution Beneath Sakurajima Volcano, Japan, from 2009 through 2014, Revealed with Rounds of Controlled-source Seismic Experiments

    NASA Astrophysics Data System (ADS)

    Tsutsui, T.; Iguchi, M.; Tameguri, T.; Nakamichi, H.

    2015-12-01

    Evolution in seismic reflectivity is detected beneath an active volcano, Sakurajima Volcano, from 2009 through 2014 with using controlled seismic experiments . The reflectivity variation is interpreted to associate with discharging magma. Sakurajima Volcano is the target of this study, which is one of the most active volcanoes in Japan. Seven rounds of the seismic experiment with controlled sources have been conducted annually in the volcano. Two seismic reflection profiles tied up are obtained from the datasets under successful reproduction during rounds. Clear annual variation in seismic reflectivity at 6.2km depth is detected in the northeastern part of Sakurajima during the rounds. The reflectivity marked its maximum on December 2009 on the first intrusion of magma and decreased gradually until December 2013, which coincides with inflation and following deflation in Sakurajima Volcano. The active reflector at 6.2km depth occupies a part of embedded clear reflector. A sandwich structure is invoked as the reflector model. Intrusion of fresh and high temperature magma into the intermediate layer of the model and its decline explains the variation range of reflectivity successfully. Our study presents one of new approaches for sensing magma properties instantaneously and for monitoring active volcanoes.

  9. Data Quality Analysis for the Bighorn Arch Seismic Array Experiment

    NASA Astrophysics Data System (ADS)

    Mancinelli, N. J.; Yang, Z.; Yeck, W. L.; Sheehan, A. F.

    2010-12-01

    We analyze background noise to assess the difference in station noise levels of different types of seismic sensors and the effects of deployed site locations, and to identify local noise sources, using the data from the Bighorn Arch Seismic Experiment (BASE). Project BASE is an EarthScope Flexible Array (FA) project and includes the deployment of 38 broadband seismometers (Guralp CMG3T), 173 short-period seismometers (L22 and CMG40T-1s), and 1850 high-frequency geophones with Reftek RT125 “Texans” in northern Wyoming, providing continuous dataset of various seismic sensor types and site locations in different geologic setups (basins and mountains). We carry out our analysis through a recently developed approach of using probability density function (PDF) to display the distribution of seismic power spectral density (PSD) [McNamara and Buland, 2004]. This new approach bypasses the tedious pre-screening for transient signals (earthquakes, mass recentering, calibration pulses, etc.) which is required by the traditional PSD analysis. Using the program PQLX, we were able to correlate specific noise sources—mine blasts, teleseisms, passing cars, etc—with features seen on PDF plots. We analyzed eight months of continuous BASE project broadband and short period data for this study. The power spectral density plots suggest that, of the 3 different instrument types used in the BASE project, the broadband CMG3T stations have the lowest background noise in the period range of 0.1-1 s while the short-period L22 stations have the highest background noise. As expected, stations located in the Bighorn Mountain Range are closer to the Low Noise Model [Peterson, 1993] than those located in the adjacent Bighorn Basin and Powder River Basin, particularly in the 0.1-1 s period range. This is mainly attributed to proximity to bedrock, though increased distance from cultural noise also contributes. At longer periods (1-100 s), the noise level of broadband instruments is lower

  10. Overview of Results from the Endeavour Seismic Tomography Experiment

    NASA Astrophysics Data System (ADS)

    Toomey, D. R.; Hooft, E. E.; Wilcock, W. S.; Weekly, R. T.; Wells, A. E.; Soule, D. C.

    2011-12-01

    We report on our continuing analyses of a multi-scale seismic tomography experiment of the Endeavour segment of the Juan de Fuca Ridge. In August 2009 we deployed 68 four-component ocean bottom seismometers (OBSs) at 64 sites throughout a 90x50 km2 area to record seismic energy from 5567 shots of the 36-element, 6600 in.3 airgun array of the R/V Marcus G. Langseth. The experimental geometry utilized 3 nested scales and was designed to image (1) crustal thickness variations within 25 km of the axial high (0 to 900 kyr); (2) the map view heterogeneity and anisotropy of the topmost mantle beneath the spreading axis; (3) the three-dimensional structure of the crustal magmatic system and (4) the detailed three-dimensional, shallow crustal thermal structure beneath the Endeavour vent fields. The 90-km-long Endeavour segment lies between the Cobb and Endeavour overlapping spreading centers (OSCs), which are converging and thus shortening the Endeavour segment. Previous seismic reflection studies indicate that the central Endeavour segment is on a 40-km-wide plateau of greater crustal thickness that is interpreted to have developed when the ridge overrode the mantle melt anomaly associated with the Heckle seamount chain. The central Endeavour is also underlain by an axial magma chamber (AMC) reflector that is shallowest and most prominent beneath the hydrothermal fields. Geophysical studies of Endeavour thus permit investigation of the competing effects of tectonic, magmatic and hydrothermal processes on crustal structure and architecture. Ongoing analyses include tomographic inversion of first-arriving P waves that sample the upper- and mid-crustal regions, characterization of off-axis magma bodies via travel time and amplitude anomalies of crustal phases, estimation of regional-scale crustal thickness variations from analysis of PmP arrivals and imaging of mantle structure using Pn to constrain mantle flow and melt distribution [Weekly et al.; Wells et al.; Soule et al

  11. Going to School: The African-American Experience.

    ERIC Educational Resources Information Center

    Lomotey, Kofi, Ed.

    This volume presents the views of a range of African-American educators on questions related to African-American academic achievement. The concern in this volume is with the persistent, pervasive, and disproportionate underachievement of African-American students. The book is divided into four parts. Part 1, "Problem Identification," comprises the…

  12. Diversifying the secondary school curriculum: The African experience

    NASA Astrophysics Data System (ADS)

    Sifuna, Daniel N.

    1992-01-01

    The paper discusses some African experiences in the diversification of secondary education, which is taken to mean curriculum change in a practical or vocational direction. This approach is intended to provide a wider set of future career options than is offered in the more uniform academic curriculum. The diversification policy has generally been seen as a solution to a number of economic and social problems facing the independent African countries, notably the increasing youth unemployment and the escalating costs of formal education. Studies which have so far been carried out have, however, revealed that diversification programmes have not met the intended objectives, although there is sustained interest in vocationalising formal education. Problems which commonly face these programmes include high unit costs, an absence of clarity in aims and objectives, a shortage of qualified teachers and the low status of vocational subjects as viewed by the students and the community. For future development, it is suggested that diversification programmes be reorganised to relate to more realistic goals through wider community participation and through the work-orientation of post-school training programmes.

  13. OSI Passive Seismic Experiment at the Former Nevada Test Site

    SciTech Connect

    Sweeney, J J; Harben, P

    2010-11-11

    its effectiveness for OSI purposes has yet to be determined. For this experiment, we took a broad approach to the definition of ''resonance seismometry''; stretching it to include any means that employs passive seismic methods to infer the character of underground materials. In recent years there have been a number of advances in the use of correlation and noise analysis methods in seismology to obtain information about the subsurface. Our objective in this experiment was to use noise analysis and correlation analysis to evaluate these techniques for detecting and characterizing the underground damage zone from a nuclear explosion. The site that was chosen for the experiment was the Mackerel test in Area 4 of the former Nevada Test Site (now named the Nevada National Security Site, or NNSS). Mackerel was an underground nuclear test of less than 20 kT conducted in February of 1964 (DOENV-209-REV 15). The reason we chose this site is because there was a known apical cavity occurring at about 50 m depth above a rubble zone, and that the site had been investigated by the US Geological Survey with active seismic methods in 1965 (Watkins et al., 1967). Note that the time delay between detonation of the explosion (1964) and the time of the present survey (2010) is nearly 46 years - this would not be typical of an expected OSI under the CTBT.

  14. Cage experiments in an East African mangrove forest: a synthesis

    NASA Astrophysics Data System (ADS)

    Schrijvers, J.; Vincx, M.

    1997-12-01

    The impact of epibenthos on endobenthos has frequently been investigated for temperate saltmarsh regions by using cage exclusion experiments. Although the insight into the function of the endobenthos of mangrove forests is crucial for their management, very few cage experiments have so far been carried out in such areas. The present paper summaries the results of such experiments in a typical East African mangrove forest at Gazi Bay about 60 km south of Mombasa, Kenya. Epibenthic animals were excluded for one year in two mangrove zones which differed in forest morphology and intertidal position ( Ceriops tagal and Avicennia marina). Environmental factors and meiobenthic and macrobenthic densities were followed in a randomised block design, and procedural and exclusion effects were statistically detected. In confronting the separate responses of all faunal groups in the two mangrove zones, this synthesis gives a better insight into the tropho-dynamical interactions than the earlier separate reports on the same experiment. The ecosystem of the mangrove zones and the competitive interactions within this system provided an ideal opportunity to discover the existence of two food systems. This confirmed a strong involvement of the majority of the endobenthos in an isolated decompositional pathway in the mangrove sediment. It became clear that this exploitative competition was more important than the epibenthic predation in structuring and regulating the global endobenthic community. This synthesis therefore both demonstrates the decisive role of the endobenthos as regenators of mangrove material, and suggests that endobenthos plays a minor role as prey for the demersal or pelagic carnivores.

  15. Representations of the Racialized Experiences of African Americans in Developmental Reading Textbooks

    ERIC Educational Resources Information Center

    Williams, Jeanine L.

    2013-01-01

    Race plays a major role in the lived experiences of African Americans. Consequently, race significantly impacts the identities and educational experiences of African American college students--many of whom require developmental reading courses. These courses, which are gateway courses in higher education, should address race along with reading…

  16. Ogbu Revisited: Unpacking High-Achieving African American Girls' High School Experiences

    ERIC Educational Resources Information Center

    Archer-Banks, Diane A. M.; Behar-Horenstein, Linda S.

    2012-01-01

    How African American girls cope and excel amidst the discriminations and inequities they experience within U.S. educational systems has not been widely discussed in the body of research about African Americans' schooling experiences. In this study, the researchers examined the applicability of Ogbu's cultural-ecological theory to the…

  17. The Perceived Undergraduate Classroom Experiences of African American Women in Science, Technology, Engineering, and Mathematics (STEM)

    ERIC Educational Resources Information Center

    Holmes, Kimberly Monique

    2013-01-01

    The purpose of this dissertation study was to explore African-American women's perceptions of undergraduate STEM classroom experiences, and the ways in which those experiences have supported or hindered their persistence in physics majors. The major research question guiding this study was: How do African-American women perceive the climate and…

  18. US Geological Survey begins seismic ground response experiments in Washington State

    USGS Publications Warehouse

    Tarr, A.C.; King, K.W.

    1988-01-01

    This article briefly describes the experimental monitoring of minor seismic features caused by distant nuclear explosions, mining blasts and rhythmic human pushing against wooden homes. Some means of response prediction are outlined in Washington State and some effects of seismic amplification by weak clayey sediments are described. The results of several experiments are described. -A.Scarth

  19. Lunar seismic profiling experiment. [Apollo 17 flight measurements of lunar surface vibrations to determine subsurface characteristics

    NASA Technical Reports Server (NTRS)

    Kovach, R. L.; Watkins, J. S.; Talwani, P.

    1973-01-01

    The Apollo 17 lunar seismic profiling experiment was conducted to record the vibrations of the lunar surface as induced by explosive charges, the thrust of the lunar module ascent engine, and the crash of the lunar module ascent stage. Analysis of the data obtained made it possible to determine the internal characteristics of the lunar crust to a depth of several kilometers. The test equipment used in the experiment is described. Maps showing the location of the geophones and the deployed explosive packages are provided. Samples of the seismic signals recorded by the lunar seismic profiling experiment geophones are included.

  20. Bandung seismic experiment: Towards tomographic imaging by using ambient seismic noise

    NASA Astrophysics Data System (ADS)

    Pranata, Bayu; Yudistira, Tedy; Saygin, Erdinc; Cummins, Phil R.; Widiyantoro, Sri; Zulfakriza, Nugraha, Andri D.

    2016-05-01

    Bandung is one of the most densely populated cities in Indonesia with vital infrastructures. On the other hand, this area is surrounded by potential sources of earthquakes that make Bandung vulnerable to earthquakes. Structure of seismic velocity and sediment thickness are crucially needed in the earthquake hazard reduction program for Bandung. Based on this consideration, we deployed 64 seismic stations over the Bandung basin to record seismic ambient noise. In this study, we employed a cross-correlation method to the simultaneously recorded data to retrieve interstation Green's functions. We measured group velocity of the retrieved Green's functions by using frequency-time analysis technique. By the end of this project, the set of interstation group velocity will be inverted to image the shallow seismic velocity structure of the Bandung basin and its surrounding areas including Mt. Tangkuban Parahu and Lembang fault. As the first stage of this work, currently we focus on Green ' s function calculation as well as the interstation group velocity measurements. The general characteristics of group velocity can be evaluated from the plot of cross-correlation function as a function of its interstation distance.

  1. Acculturative Experiences of Black-African International Students

    ERIC Educational Resources Information Center

    Boafo-Arthur, Susan

    2014-01-01

    There has been a significant increase in the number of international students pursuing higher education in the U.S. since 2001. Upon arrival, students are often beset with feelings of isolation and alienation, which are characteristic of adjusting to a new culture. African International students, specifically Black-African international students,…

  2. Experiences of African American Empowerment: A Jamesian Perspective on Agency

    ERIC Educational Resources Information Center

    Curtis-Tweed, Phyllis

    2003-01-01

    This essay draws from the work of William James and three African American pragmatists, W.E.B. Du Bois, Ralph Ellison and Cornel West, to explore the moral relevance of the self as an empowered agent among African American youth. The focus is on Jamesian agency as a function of the individual's awareness of options in context, the self-empowerment…

  3. An Examination of the Lived Experiences of Successful African American Men Attending a Historically Black University

    ERIC Educational Resources Information Center

    Powell, Clark R.

    2013-01-01

    This phenomenological research explored the lived experiences of successful African American men attending a Historically Black College and University (HBCU) in the Midwest. The guiding questions for the study were (a) What positive characteristics do successful African American men demonstrate at HBCUs that offset major problems, concerns, and…

  4. Unheard and Unseen: How Housing Insecure African American Adolescents Experience the Education System

    ERIC Educational Resources Information Center

    Ellis, Addie Lucille; Geller, Kathy D.

    2016-01-01

    This narrative study is based on stories told by African American adolescents experiencing homelessness. It offers insights into their lived experiences and describes the challenges faced in negotiating the urban education system. African American youth are disproportionately represented in the adolescent homeless demographic. "Unheard and…

  5. Experiences of Chinese International Students Learning English at South African Tertiary Institutions

    ERIC Educational Resources Information Center

    Ayliff, D.; Wang, G.

    2006-01-01

    This article aims to provide insight into the experiences of Chinese international students in some South African tertiary institutions. The study investigates their successes and failures in endeavouring to learn English and the culture shock and "learning shock" they endure when registering to study in an African country with an essentially…

  6. Exploring the Meaning African American PETE Teacher Candidates Ascribe to Their Aquatic Experiences

    ERIC Educational Resources Information Center

    Sato, Takahiro; Hodge, Samuel R.

    2012-01-01

    Physical Education Teacher Education (PETE) programs typically require their graduates to learn to swim proficiently. However, the research base is underdeveloped regarding the aquatic experiences of African Americans in PETE programs. The purpose of this study was to explore the meaning African American PETE teacher candidates ascribe to their…

  7. Black African Parents' Experiences of an Educational Psychology Service

    ERIC Educational Resources Information Center

    Lawrence, Zena

    2014-01-01

    The evidence base that explores Black African parents' experiences of an Educational Psychology Service (EPS) is limited. This article describes an exploratory mixed methods research study undertaken during 2009-2011, that explored Black African parents' engagement with a UK EPS. Quantitative data were gathered from the EPS preschool…

  8. Local seismic events in area of Poland based on data from PASSEQ 2006-2008 experiment

    NASA Astrophysics Data System (ADS)

    Polkowski, Marcin; Plesiewicz, Beata; Wiszniowski, Jan; Wilde-Piórko, Monika; Passeq Working Group

    2014-05-01

    PASSEQ 2006-2008 (Passive Seismic Experiment in TESZ; Wilde-Piórko et al, 2008) was the biggest so far passive seismic experiment in the area of Central Europe (Poland, Germany, Czech Republic and Lithuania). 196 seismic stations (including 49 broadband seismometers) worked simultaneously for over two years. During experiment multiple types of data recorders and seismometers were used making analysis more complex and time consuming. Dataset was unified and repaired to start the detection of local seismic events. Two different approaches for detection were applied for stations located in Poland. One used standard STA/LTA triggers (Carl Johnson's STA/LTA algorithm) and grid search to classify and locate events. Result was manually verified. Other approach used Real Time Recurrent Network (RTRN) detection (Wiszniowski et al, 2014). Both methods gave similar results showing four previously unknown seismic events located in area of Gulf Of Gdańsk in southern Baltic Sea. The investigation of local seismicity is a good opportunity for verification of new seismic models of lithosphere in the area. In this paper we discuss both detection methods with their pros and cons (accuracy, efficiency, manual work required, scalability). We also show details of all detected and previously unknown events in discussed area. This work was partially supported by NCN grant UMO-2011/01/B/ST10/06653.

  9. Seismic evaluation of a diesel generator system at the Savannah River Site using earthquake experience data

    SciTech Connect

    Griffin, M.J.; Tong, Wen H.; Rawls, G.B.

    1990-12-31

    New equipment and systems have been seismically qualified traditionally by either two methods, testing or analysis. Testing programs are generally expensive and their input loadings are conservative. It is generally recognized that standard seismic analysis techniques produce conservative results. Seismic loads and response levels for equipment that are typically calculated exceed the values actually experienced in earthquakes. An alternate method for demonstrating the seismic adequacy of equipment has been developed which is based on conclusions derived from studying the performance of equipment that has been subjected to actual earthquake excitations. The conclusion reached from earthquake experience data is that damage or malfunction to most types of equipment subjected to earthquakes is less than that predicted by traditional testing and analysis techniques. The use of conclusions derived from experience data provides a realistic approach in assessing the seismic ruggedness of equipment. By recognizing the inherently higher capacity that exists in specific classes of equipment, commercial ``off-the-shelf`` equipment can be procured and qualified without the need to perform expensive modifications to meet requirements imposed by traditional conservative qualification analyses. This paper will present the seismic experience data methodology applied to demonstrate the seismic adequacy of several commercially supplied 800KW diesel powered engine driven generator sets with peripheral support components installed at the Savannah River Site (SRS).

  10. Seismic evaluation of a diesel generator system at the Savannah River Site using earthquake experience data

    SciTech Connect

    Griffin, M.J.; Tong, Wen H. ); Rawls, G.B. )

    1990-01-01

    New equipment and systems have been seismically qualified traditionally by either two methods, testing or analysis. Testing programs are generally expensive and their input loadings are conservative. It is generally recognized that standard seismic analysis techniques produce conservative results. Seismic loads and response levels for equipment that are typically calculated exceed the values actually experienced in earthquakes. An alternate method for demonstrating the seismic adequacy of equipment has been developed which is based on conclusions derived from studying the performance of equipment that has been subjected to actual earthquake excitations. The conclusion reached from earthquake experience data is that damage or malfunction to most types of equipment subjected to earthquakes is less than that predicted by traditional testing and analysis techniques. The use of conclusions derived from experience data provides a realistic approach in assessing the seismic ruggedness of equipment. By recognizing the inherently higher capacity that exists in specific classes of equipment, commercial off-the-shelf'' equipment can be procured and qualified without the need to perform expensive modifications to meet requirements imposed by traditional conservative qualification analyses. This paper will present the seismic experience data methodology applied to demonstrate the seismic adequacy of several commercially supplied 800KW diesel powered engine driven generator sets with peripheral support components installed at the Savannah River Site (SRS).

  11. Experiences of african american parents following perinatal or pediatric death: a literature review.

    PubMed

    Boyden, Jackelyn Y; Kavanaugh, Karen; Issel, L Michele; Eldeirawi, Kamal; Meert, Kathleen L

    2014-01-01

    A child's death is one of life's most difficult experiences. Little is known about the unique factors that influence the grief experience for bereaved African American parents. Through an integrative review of 10 publications, the authors describe the grief responses, outcomes, and implications for African American parents who experience the death of a child. Four themes emerged: (a) emotional response to loss; (b) factors that added to the burden of loss; (c) coping strategies; and (d) health consequences of grief. Healthcare providers, administrators, and policymakers should be sensitive to the unique needs of African American parents following a child's death.

  12. Recent Seismic Experiments of OBS in the South China Sea

    NASA Astrophysics Data System (ADS)

    Ruan, A.; Li, J.; Wu, Z.

    2012-12-01

    Since 2006 some research institutions of China have carried out some important seismic experiments by using ocean bottom seismometer(OBS) in the South China Sea (SCS) and obtained many concrete progresses in modeling the crustal structure of SCS and also in understanding of its formation and evolution as well. In 2006 three wide-angle profiles were completed in the northern margin, named OBS2006-1 across the northwestern sub-basin, OBS2006-2 parallel to the sea basin boundary and OBS2006-3 across the Dongsha Rise and Chaoshan Depression respectively. In 2010 two wide- angle profiles were completed, named OBS2010-1 and OBS 2010-2 both perpendicular to the northern off-shore faulting system. During 2009-2011 four wide-angle profiles were completed in the southern margin, named OBS973-1 from southern margin to the southwestern sub-basin, OBS973-2 from Liyue Bank to the southwestern sub-basin and OBS973-3 from Xisha to the southwestern sub-basin, OBS2011-2 from Xisha to Hainan Island respectively. In 2011 two 3D seismic array of OBS were completed in the Zhongnan-Changlong sea mount chain and Huangyan-Zhenbei sea mount chain respectively. Here we present some primary but important results as follows. (1) The velocity model of OBS2006-1 indicates that the crust under the continental slope decreases from 21km to 11km, and to 7.7km in the northwestern sub-basin with Moho depth ascends from 21km to 11km. The tectonic geometry and velocity structure of the northwestern sub-basin and its margins on both sides shows symmetrical and conjugate and indicates pure shear mode of continental margin rifting mechanism. (2) The velocity model of OBS2006-3 reveals remarkable thickness with maximum 8 km of the Mesozoic sediment in Chaoshan Depression in which velocity increases downward from 4.4 km/s at top to 5.3 km/s at the bottom. The buried depth of Moho decreases from 24-25 km under Dongsha Rise to 17 km in the lower slope and an obviously velocity abnormal is detected in the upper

  13. The role of spirituality in the breast cancer experiences of African American women.

    PubMed

    Tate, Johnetta D

    2011-12-01

    Breast cancer is the most commonly diagnosed cancer type among African American women. African American women often use spirituality to overcome the physical, psychological, and emotional burdens that accompany a breast cancer diagnosis. Spirituality has been used over the years by African American women to bring hope when dealing with hardships. This integrative review seeks to explore the importance of spirituality to African American women throughout the breast cancer experience. Thirteen qualitative and quantitative studies that discussed how spirituality was used to cope with breast cancer from initial diagnosis to survivorship were reviewed. Spirituality was found to be the main coping mechanism used during all phases of the cancer experience. To provide holistic nursing care, nurses must understand that spirituality is an important coping strategy used by most African American women with breast cancer. The implications for nursing that were identified include the incorporation of spiritual interventions and the utilization of culturally appropriate assessment tools.

  14. A strategy for implementation of experience based seismic equipment qualification in IEEE and ASME industry standards

    SciTech Connect

    Adams, T.M.

    1996-12-01

    In the past 20 years, extensive data on the performance of mechanical and electric equipment during actual strong motion earthquakes and seismic qualification tests has been accumulated. Recognizing that an experience based approach provides a technically sound and cost effective method for the seismic qualification of some or certain equipment, the IEEE Nuclear Power Engineering Committee and the ASME Committee on Qualification of Mechanical Equipment established a Special Working Group to investigate the incorporation of experienced based methods into the industry consensus codes and standards currently used in the seismic qualification of Seismic Category Nuclear Power Plant equipment. This paper presents the strategy (course of action) which was developed by the Special Working Group for meeting this objective of incorporation of experience based seismic qualification standards used in the design and seismic qualification of seismic category nuclear power plant equipment. This strategy was recommended to both chartering organizations, the IEEE Nuclear Power Engineering Committee and the ASME Committee on Qualification of Mechanical Equipment for their consideration and implementation. The status of the review and implementation of the Special Working Group`s recommended strategy by the sponsoring organization is also discussed.

  15. Pacific Upper Mantle Seismic Anisotropy from the Active-Source Seismic Component of the NoMelt Experiment

    NASA Astrophysics Data System (ADS)

    Mark, H. F.; Lizarralde, D.; Gaherty, J. B.; Collins, J. A.; Hirth, G.; Evans, R. L.

    2014-12-01

    We will present a measurement of azimuthal seismic anisotropy of Pacific-plate upper mantle based on Pn travel times from the active-source seismic component of the NoMelt experiment. The NoMelt experiment was conducted in 2012 on ~70-m.y.-old lithosphere, in the center of the spreading segment between the Clarion and Clipperton fracture zones, with the goal of delineating the detailed seismic and electrical structure of "normal," mature oceanic lithosphere. The seismic component of the experiment consisted of a 600x400 km array of 27 broad-band (BB) ocean bottom seismometers (OBS); 31 short period (SP) OBS, spaced at 20 km, deployed along the long axis of the array (the main transect), oriented along a plate-kinematic flow line; and 3 SP OBS deployed along a line normal to the main transect, at 50 km spacing, extending to 200 km southeast of the center of the main transect. The SP OBS array was deployed to record airgun shots fired by the R/V M.G. Langseth's 36-element array. Airgun shots were fired along the two perpendicular lines and also along a semi-circular arc with a 75-km radius centered at the line intersection at the center of the main transect. Pn (upper mantle refraction) arrivals from shots fired along the semicircle and recorded by OBS within the semicircle's arc span 180 degrees of azimuth and an offset range of ~40-150 km. Preliminary analyses of these Pn arrival travel times indicate an azimuthal dependence of P-wave speeds, which range from ~8.6 km/s to ~7.6 km/s. These preliminary results suggest a pattern of azimuthal wave-speed dependence that requires depth-dependent seismic anisotropy and/or a dipping mantle fabric, with the latter being more likely given the limited range of source/receiver offsets spanned by the Pn arrivals used in this analysis. We will present results that include these observations as well as Pn arrivals from a much more comprehensive set of source/receiver pairs from the NoMelt experiment.

  16. The Will to Achieve: A Phenomenological Study of the Experiences of African American High Achieving Students and Their Parents

    ERIC Educational Resources Information Center

    Spencer, Natalie Faye

    2012-01-01

    The purpose of this research study was to understand the experiences of high achieving African American students and their parents. The experiences of high achieving African American students and their parents have been missing from literature on the academic achievement of African American students. Much of the literature that has been published…

  17. The Soul of Leadership: African American Students' Experiences in Historically Black and Predominantly White Organizations

    ERIC Educational Resources Information Center

    Hotchkins, Bryan K.

    2013-01-01

    This study addresses African American students' leadership experiences at predominantly White institutions. Findings indicated participants utilized servant leadership in historically Black organizations and transformational leadership in predominantly White organizations. The differences displayed showed that participants' leadership perceptions…

  18. Las Vegas Basin Seismic Response Project: Preliminary Results From Seismic Refraction Experiments, Las Vegas, NV.

    NASA Astrophysics Data System (ADS)

    Zaragoza, S. A.; Snelson, C. M.; Harder, S. H.; Kaip, G.; Luke, B.; Buck, B. J.; Hanson, A. D.

    2002-12-01

    In May and September 2002, seismic refraction data were acquired in the Las Vegas basin. Located in the southern Basin and Range province, the cities of Las Vegas, North Las Vegas, and Henderson sit atop a fault-bounded basin with a depth of up to 5 km and basin dimensions of roughly 60 km wide (east-west) by 50 km in length (north-south). Previous isostatic gravity, seismic reflection, and aeromagnetic studies indicate that a series of sub-basins exist beneath the unconsolidated basin fill, with the deepest sub-basin occurring 5 km west of the fault block bounding the eastern edge of the basin (Frenchman Mountain). The basin is significantly deeper along its northern extremity, following the path of the fault block bounding the northern edge of the basin (Las Vegas Valley Shear Zone), and along the western edge of Frenchman Mountain. Recent, paleoseismic studies have indicated that faults in the Las Vegas region have the potential for an earthquake of M6.5 to 7.0. It is estimated that a M6.9 earthquake in the basin could produce about 11 billion dollars in damage and a significant number of deaths and/or injuries. In addition, an equivalent or larger event in the Death Valley fault zone, 150 km distance, would also be devastating to the metropolitan area of approximately 1.5 million residents. Therefore, it is essential to understand the seismic hazard posed to the Las Vegas region. This project is part of a larger collaborative effort to characterize the basin and its response to ground shaking. The University of Nevada, Las Vegas with assistance from the University of Texas at El Paso, students from UNLV and UTEP, volunteers from the community and several students from Centennial High school deployed 432 portable seismic recorders ("Texans") throughout the valley. Shot point locations were located at three quarries in the valley, one to the north, one to the east and one to the southwest. The profiles cross the Las Vegas Valley Shear zone as well as a prominent

  19. Deep seismic exploration into the Arctic Lithosphere: Arctic-2012 Russian wide-angle seismic experiment

    NASA Astrophysics Data System (ADS)

    Kashubin, S.

    2013-12-01

    Integrated geological and geophysical studies of the Earth's crust and upper mantle (the Russian project 'Arctic-2012') were carried out in 2012 in the Mendeleev Rise, central Arctic. The set of studies included wide-angle seismic observations along the line crossing the Mendeleev Rise in its southern part. The DSS seismic survey was aimed at the determination of the Mendeleev Rise crust type. A high-power air gun (120 liters or 7320 cu.in) and ocean stations with multi-component recording (X, Y, Z geophone components and a hydrophone) were used for the DSS. The line was studied using a dense system of observation: bottom station spacing was from 10 to 20 km, excitation point spacing (seismic traces interval) was 315 m. Observation data were obtained in 27 location points of bottom stations, the distance between the first and the last stations was 480 km, the length of the excitation line was 740 km. In DSS wave fields, in the first and later arrivals, there are refracted and reflected waves associated with boundaries in the sedimentary cover, with the top of the basement, and with boundaries in the consolidated crust, including its bottom (Moho discontinuity). The waves could be traced for offsets up to 170-240 km. The DSS line coincides with the near-vertical CMP line worked out with the use of a 4500-m-long seismic streamer and with a 50 m shot point interval that allowed essential detalization of the upper part of the section and taking it into account in the construction of a deep crust model. The deep velocity model was constructed using ray-trace modeling of compressional, shear, and converted waves with the use of the SeisWide program. Estimates were obtained for Vp/Vs velocity ratios, which played an important role in determining the type of crust. The results of the interpretation show that the Mendeleev Rise section corresponds to sections of a thin continental crust of shelf seas and a thinned continental crust of submarine ridges and rises.

  20. DEVELOPING AND EXPLOITING A UNIQUE SEISMIC DATA SET FROM SOUTH AFRICAN GOLD MINES FOR SOURCE CHARACTERIZATION AND WAVE PROPAGATION

    SciTech Connect

    Julia, J; Nyblade, A A; Gok, R; Walter, W R; Linzer, L; Durrheim, R

    2008-07-08

    In this project, we are developing and exploiting a unique seismic data set to address the characteristics of small seismic events and the associated seismic signals observed at local (< 200 km) and regional (< 2000 km) distances. The dataset is being developed using mining-induced events from 3 deep gold mines in South Africa recorded on inmine networks (< 1 km) comprised of tens of high-frequency sensors, a network of 4 broadband stations installed as part of this project at the surface around the mines (1-10 km), and a network of existing broadband seismic stations at local/regional distances (50-1000 km) from the mines. After 1 year of seismic monitoring of mine activity (2007), over 10,000 events in the range -3.4 < ML < 4.4 have been catalogued and recorded by the in-mine networks. Events with positive magnitudes are generally well recorded by the surface-mine stations, while magnitudes 3.0 and larger are seen at regional distances (up to {approx}600 km) in high-pass filtered recordings. We have analyzed in-mine recordings in detail at one of the South African mines (Savuka) to (i) improve on reported hypocentral locations, (ii) verify sensor orientations, and (iii) determine full moment tensor solutions. Hypocentral relocations on all catalogued events have been obtained from P- and S-wave travel-times reported by the mine network operator through an automated procedure that selects travel-times falling on Wadati lines with slopes in the 0.6-0.7 range; sensor orientations have been verified and, when possible, corrected by correlating P-, SV-, and SH-waveforms obtained from theoretical and empirical (polarization filter) rotation angles; full moment tensor solutions have been obtained by inverting P-, SV-, and SH- spectral amplitudes measured on the theoretically rotated waveforms with visually assigned polarities. The relocation procedure has revealed that origin times often necessitate a negative correction of a few tenths of second and that hypocentral

  1. High-resolution seismic exploration methods for boreholes and tunnels: experiments, results and test site design

    NASA Astrophysics Data System (ADS)

    Giese, R.; Harms, U.; Jaksch, K.; Krüger, K.

    2012-12-01

    While surface to ground seismic exploration methods are well known, the utilization of seismic waves for underground surveying is less developed. The major challenge in subsurface seismics is the spatial ambiguity of the recorded wave field due to limited aperture of seismic source and receiver survey geometry. We developed novel imaging techniques and the appropriate measurement systems like phased array borehole sources for directional enhancement of seismic wave energy. Different procedures such as 3-component Kirchhoff-Migration and Fresnel-Volume-Migration were tested and improved to enhance the spatial resolution. The goal of these new approaches is to advance instruments for the detection of small-scale tectonic features or lithological changes in boreholes and tunnels. The key component for the experiments was the setup of our underground lab 150 m below surface (education and research mine Reiche Zeche, TU Freiberg, SE Germany). Surrounded by three galleries, the site comprises a block of homogeneous high-grade gneisses of about 50 m width and 100 m length ensuring constant environmental conditions. Along the galleries thirty 3-component geophones are anchored 1-2 m deep with a distance of 4-9 m from each other. Within this test site, two horizontal 8 ½" boreholes (20 and 30 m long) as well as a vertical hole (70 m depth) allow for 3D nearfield seismic experiments for high-resolution exploration and monitoring of geological structures.

  2. Extension and Basin Evolution of the East Kivu Graben, Rwanda, East African Rift: Results of New Multichannel Seismic Reflection Imaging

    NASA Astrophysics Data System (ADS)

    Scholz, C. A.; Zhang, X.; Wood, D.; Mburu, D.

    2012-12-01

    The East Kivu Graben resides within the eastern part of Lake Kivu, the highest Great Lake in the western branch of the East African Rift. The lake is more than 440 m deep in the East Kivu Basin, with a catchment comprised of Precambrian metasedimentary rocks and late-Cenozoic volcanics. Lake Kivu is renowned for its uniquely stratified water column, which is charged with considerable quantities of dissolved CO2 and methane, the former due to magmatic degassing. In February and March 2012 514 km of single- and multi-channel seismic reflection data were acquired in the Rwandan waters of Lake Kivu. The 24-fold multichannel seismic data were acquired aboard a modular research vessel, using a 600 m-long hydrophone streamer and single 40 cubic inch airgun. Extension in the East Kivu basin is largely accommodated along a major N-S striking, east-dipping boundary fault observed along the eastern edge of Iwawa Island, and extending for ~40 km along the length of the basin. Numerous intrabasinal normal faults occur to the east of the boundary fault, commonly displacing the lake floor and controlling the location of modern sublacustrine channels. The deepest sedimentary reflections observed on the new MCS data are 1.2-1.5 km below lake floor, near the center of the basin and boundary fault. Crystalline basement is not observed in these deepest areas however, suggesting the presence of a substantial sedimentary section below the imaged strata. Stratal surfaces dip steeply to the west over large areas of the half-graben basin. An acoustically transparent seismic sequence up to ~25 m thick is observed at the lake floor, which overlies a pronounced erosional unconformity over much of the basin. Some intrabasinal normal faults are draped by and do not penetrate the upper sequences, indicating several generations of fault activity in the basin. The late-Pleistocene exposure surface likely correlates to the previous lake level low stage that persisted prior to volcanic damming by

  3. Structural evolution beneath Sakurajima Volcano, Japan, revealed through rounds of controlled seismic experiments

    NASA Astrophysics Data System (ADS)

    Tsutsui, Tomoki; Iguchi, Masato; Tameguri, Takeshi; Nakamichi, Haruhisa

    2016-04-01

    Structural evolution beneath an active volcano is detected as the variation of seismic reflectivity through controlled seismic experiments, which is interpreted as being associated with discharging magma. The target of the present study is Sakurajima Volcano, which is one of the most active volcanoes in Japan. Six rounds of seismic experiments with controlled sources have been conducted annually at the volcano. Two seismic reflection profiles are obtained from the datasets for each successful round of experiments. The experiments reveal clear annual variation in seismic reflectivity at a depth of 6.2 km in the northeastern part of Sakurajima. The reflectivity is maximum in December 2009 upon the first intrusion of magma and decreases gradually until December 2013, which coincides with the inflation and deflation cycle of Sakurajima Volcano. Reflectivity variation occurred in the embedded clear reflector at depth. An evolving sandwiched structure in the intermediate layer is used as the reflector model. Lower-velocity magma embedded in the intermediate layer and its succeeding velocity increment explain the variation range of reflectivity. This is interpreted as a temperature decrease associated with discharging magma at depth. The present study describes a new approach for instantaneously sensing magma properties and for monitoring active volcanoes.

  4. Immersion and Identity: Experiences of an African American Preschool Child

    ERIC Educational Resources Information Center

    McCullough, Ruanda Garth; Reyes, Sharon Adelman

    2010-01-01

    This article explores the benefits and challenges of a Spanish language immersion preschool from the perspective of a non-Spanish speaking African American family. Data explored include the decision to enroll, reactions from peers and family, home-school communication issues, language development, and family involvement. In addition,…

  5. Leadership Development and the African American Male College Student Experience

    ERIC Educational Resources Information Center

    Oaks, D'Arcy John; Duckett, Kirstan; Suddeth, Todd; Kennedy-Phillips, Lance

    2013-01-01

    Qualitative interviews were employed to assess the effectiveness of a leadership program geared toward African American male personal and professional development, and to examine the relationship between program participation and connectedness. Elements of both social engagement (mentoring and being mentored, peer-to-peer relationships, and…

  6. The South African Experience: Beyond the CIDA Model

    ERIC Educational Resources Information Center

    Bruton, John M.

    2008-01-01

    The Community and Individual Development Association (CIDA) City Campus is presented by Heaton as an innovative African alternative to traditional business education. However, he considers the model in isolation from the unique educational and economic circumstances of postapartheid South Africa. As a response, this article goes beyond the CIDA…

  7. The Amistad Research Center: Documenting the African American Experience.

    ERIC Educational Resources Information Center

    Chepesiuk, Ron

    1993-01-01

    Describes the Amistad Research Center housed at Tulane University which is a repository of primary documents on African-American history. Topics addressed include the development and growth of the collection; inclusion of the American Missionary Association archives; sources of support; civil rights; and collecting for the future. (LRW)

  8. Multi Scale Imaging of Seismic Structure beneath the Western Branch of the East-African Rift

    NASA Astrophysics Data System (ADS)

    Jakovlev, A.; Rumpker, G.; Koulakov, I.

    2010-12-01

    In this study, we investigate the crustal and upper mantle velocity structure beneath the East African Rift System (EARS) as a whole and beneath the Rwenzori Mountains in western Uganda in particular. The most interesting features here is the mountain range of approximately 50 km-wide, with a length of about 150 km, which is situated within the western branch of the East African rift zone and reaches the altitudes of more than 5000 m. The joint tomographic inversion was used to investigate the velocity structure beneath the Rwenzoris on a local scale down to the depth of about 75 - 80 km. Arrival times from 2053 local and 284 teleseismic earthquakes recorded by a temporary network equipped 35 short period and broad-band stations were used as an input for the joint tomographic inversion. The network is covering an area of 140×90 km2. To estimate resolution ability and stability of the obtained results we performed many different tests. The tests show that the best horizontal resolution is achieved in the northern part of the study area, where the density of the ray coverage is highest. In shallow depths where local earthquake rays dominate, the vertical and horizontal resolution is relatvely high, while in deeper sections covered with teleseismic rays, the anomalies seem to be strongly smeared and can be interpreted only on a qualitative level. Velocity structure in the upper crust agrees with the distribution of the main geological units, such as sedimentary basins, igneous outcrops, thermal fields etc. For the uppermost mantle, our results reveal an inclined boundary between the high-velocity Tanzania craton and low-velocity patterns beneath the rift. The same position of the contact between craton and rift zone was obtained in the regional tomographic study of the EARS as a whole. This regional study was based on the ISC data, which contains information about arrival times of signals from earthquakes at more than 7000 stations of the global seismological network

  9. A Comparison of Seismicity Characteristics and Fault Structure Between Stick-Slip Experiments and Nature

    NASA Astrophysics Data System (ADS)

    Goebel, T. H. W.; Sammis, C. G.; Becker, T. W.; Dresen, G.; Schorlemmer, D.

    2015-08-01

    Fault zones contain structural complexity on all scales. This complexity influences fault mechanics including the dynamics of large earthquakes as well as the spatial and temporal distribution of small seismic events. Incomplete earthquake records, unknown stresses, and unresolved fault structures within the crust complicate a quantitative assessment of the parameters that control factors affecting seismicity. To better understand the relationship between fault structure and seismicity, we examined dynamic faulting under controlled conditions in the laboratory by creating saw-cut-guided natural fractures in cylindrical granite samples. The resulting rough surfaces were triaxially loaded to produce a sequence of stick-slip events. During these experiments, we monitored stress, strain, and seismic activity. After the experiments, fault structures were imaged in thin sections and using computer tomography. The laboratory fault zones showed many structural characteristics observed in upper crustal faults, including zones of localized slip embedded in a layer of fault gouge. Laboratory faults also exhibited a several millimeter wide damage zone with decreasing micro-crack density at larger distances from the fault axis. In addition to the structural similarities, we also observed many similarities between our observed distribution of acoustic emissions (AEs) and natural seismicity. The AEs followed the Gutenberg-Richter and Omori-Utsu relationships commonly used to describe natural seismicity. Moreover, we observed a connection between along-strike fault heterogeneity and variations of the Gutenberg-Richter b value. As suggested by natural seismicity studies, areas of low b value marked the nucleation points of large slip events and were located at large asperities within the fault zone that were revealed by post-experimental tomography scans. Our results emphasize the importance of stick-slip experiments for the study of fault mechanics. The direct correlation of

  10. Large-N Seismic Deployment at the Source Physics Experiment (SPE) Site

    NASA Astrophysics Data System (ADS)

    Chen, T.; Snelson, C. M.; Mellors, R. J.; Pitarka, A.

    2015-12-01

    The Source Physics Experiment (SPE) is multi-institutional and multi-disciplinary project that consists of a series of chemical explosion experiments at the Nevada National Security Site. The goal of SPE is to understand the complicated effect of earth structures on source energy partitioning and seismic wave propagation, develop and validate physics-based monitoring, and ultimately better discriminate low-yield nuclear explosions from background seismicity. Deployment of a large number of seismic sensors is planned for SPE to image the full 3-D wavefield with about 500 three-component sensors and 500 vertical component sensors. This large-N seismic deployment will operate near the site of SPE-5 shot for about one month, recording the SPE-5 shot, ambient noise, and additional controlled-sources. This presentation focuses on the design of the large-N seismic deployment. We show how we optimized the sensor layout based on the geological structure and experiment goals with a limited number of sensors. In addition, we will also show some preliminary record sections from deployment. This work was conducted under Contract No. DE-AC52-06NA25946 with the U.S. Department of Energy.

  11. An induced seismicity experiment across a creeping segment of the Philippine Fault

    NASA Astrophysics Data System (ADS)

    Prioul, R.; Cornet, F. H.; Dorbath, C.; Dorbath, L.; Ogena, M.; Ramos, E.

    2000-06-01

    The location of seismicity induced by forced fluid flow provides information about domains of pore pressure variation, while changes in fluid content are identified through changes in seismic velocity. These effects have been investigated in the geothermal field of Tongonan, which lies on a creeping portion of the Philippine Fault on Ley te Island. Locally, the left-lateral strike-slip Philippine Fault branches out into three subparallel segments (Eastern, Central and Western Fault Lines). In June-July 1997, a water stimulation was undertaken in a well that intersects the Central Fault Line 1980 m below ground surface; 36,000 m3 were injected between the casing shoe at 1308 m and the well bottom at 2177 m. The seismicity was monitored with a surface station network of 18 stations. More than 400 events, induced by the injection experiment as well as by routine injections associated with the geothermal field exploitation, were recorded in the vicinity of the well. They have been located through a simultaneous three-dimensional (3-D) velocity-hypocenter inversion procedure. None of the microearthquakes are located along the Central Fault Line, they all occurred below the casing shoe to the east of the fault line, i.e., within the geothermal reservoir and mostly below the bottom of the well. Results from the injection experiment and the 18 months of seismic monitoring along the Central and West Fault Lines suggest an aseismic behavior of this major continental fault at this location. The 3-D velocity model, determined from the travel time inversion for seismic events observed during injections, is compared to that obtained from seismic monitoring conducted prior to any injection activities. An increase of P wave velocity is observed during the water injection. This velocity increase is localized within the seismicity cloud and is interpreted as an increase in liquid content within the initial liquid-vapor multiphase part of the reservoir.

  12. Experiences of African American Young Women in Science, Technology, Engineering, and Mathematics (STEM) Education

    NASA Astrophysics Data System (ADS)

    Kolo, Yovonda Ingram

    African American women are underrepresented in science, technology, engineering, and mathematics (STEM) fields throughout the United States. As the need for STEM professionals in the United States increases, it is important to ensure that African American women are among those professionals making valuable contributions to society. The purpose of this phenomenological study was to describe the experiences of African American young women in relation to STEM education. The research question for this study examined how experiences with STEM in K-10 education influenced African American young women's academic choices in their final years in high school. The theory of multicontextuality was used to provide the conceptual framework. The primary data source was interviews. The sample was composed of 11 African American young women in their junior or senior year in high school. Data were analyzed through the process of open coding, categorizing, and identifying emerging themes. Ten themes emerged from the answers to research questions. The themes were (a) high teacher expectations, (b) participation in extra-curricular activities, (c) engagement in group-work, (d) learning from lectures, (e) strong parental involvement, (f) helping others, (g) self-efficacy, (h) gender empowerment, (i) race empowerment, and (j) strategic recruitment practices. This study may lead to positive social change by adding to the understanding of the experiences of African American young women in STEM. By doing so, these findings might motivate other African American young women to pursue advanced STEM classes. These findings may also provide guidance to parents and educators to help increase the number of African American women in STEM.

  13. Psychopathology, adversity, and creativity: diversifying experiences in the development of eminent African Americans.

    PubMed

    Damian, Rodica Ioana; Simonton, Dean Keith

    2015-04-01

    Symptoms associated with mental illness have been hypothesized to relate to creative achievement because they act as diversifying experiences. However, this theory has only been tested on predominantly majority-culture samples. Do tendencies toward mental illness still predict eminent creativity when they coexist with other diversifying experiences, such as early parental death, minority-status, or poverty? These alternative diversifying experiences can be collectively referred to as examples of developmental adversity. This conjecture was tested on a significant sample of 291 eminent African Americans who, by the nature of their status as long-term minorities, would experience more developmental adversity. Replicating majority-culture patterns, African American artists showed higher mental illness rates than African American scientists. Yet the absolute percentages were significantly lower for the African Americans, regardless of profession. Furthermore, mental illness predicted higher eminence levels only for the African American artists, an effect that diminished when controlling for developmental adversity. Because the latter predicted eminence for both artists and scientists, the "madness-to-genius" link probably represents just 1 of several routes by which diversifying experiences can influence eminence. The same developmental ends can be attained by different means. This inference warrants further research using other eminent creators emerging from minority culture populations.

  14. Caregiver Experiences of Discrimination and African American Adolescents' Psychological Health over Time

    ERIC Educational Resources Information Center

    Ford, Kahlil R.; Hurd, Noelle M.; Jagers, Robert J.; Sellers, Robert M.

    2013-01-01

    The present study examined the effect of caregivers' experiences of racial discrimination on their adolescent children's psychological functioning among a sample of 264 African American dyads. Potential relations between caregiver discrimination experiences and a number of indicators of adolescents' (aged 12-17) psychological functioning over time…

  15. African American and European American Therapists' Experiences of Addressing Race in Cross-Racial Psychotherapy Dyads

    ERIC Educational Resources Information Center

    Knox, Sarah; Burkard, Alan W.; Johnson, Adanna J.; Suzuki, Lisa A.; Ponterotto, Joseph G.

    2003-01-01

    Using Consensual Qualitative Research, 12 licensed psychologists' overall experiences addressing race in psychotherapy were investigated, as were their experiences addressing race in a specific cross-racial therapy dyad. Results indicated that only African American psychologists reported routinely addressing race with clients of color or when race…

  16. The Lived Experiences of African American Women with Breast Cancer: Implications for Counselors

    ERIC Educational Resources Information Center

    Clay, LaTasha K.

    2013-01-01

    Qualitative phenomenological methodology was used to explore the lived experiences of African American women diagnosed with breast cancer. Phenomenology focuses on the meaning of the lived experiences of individuals experiencing a concept, structure, or phenomenon (Creswell, 2007). The purpose of phenomenological research is to identify phenomena…

  17. We fall down: the African American experience of coping with the homicide of a loved one.

    PubMed

    Sharpe, Tanya L; Boyas, Javier

    2011-01-01

    Rates of homicide among African Americans are much higher than those of other racial or ethnic groups. Research has demonstrated that homicide can be psychologically debilitating for surviving family members. Yet, exploring the experiences of homicide victims’ surviving loved ones has received little attention. This study examined the coping strategies of African American survivors of homicide. Qualitative interviews were conducted with 8 African American family members (ages 18-82) of homicide victims. Survivors were recruited from the Massachusetts Office of Victim Services and from homicide survivor support, school, and community groups throughout the New England area. Interviews were conducted using open-ended questions derived from coping, support network, grief, and bereavement literatures. Results indicate that the primary coping strategies utilized by African American survivors of homicide victims are spiritual coping and meaning making, maintaining a connection to the deceased, collective coping and caring for others, and concealment. Implications for research and practice are discussed. PMID:22073426

  18. Imaging the deep seismic structure beneath a mid-ocean ridge: the MELT experiment

    PubMed

    1998-05-22

    The Mantle Electromagnetic and Tomography (MELT) Experiment was designed to distinguish between competing models of magma generation beneath mid-ocean ridges. Seismological observations demonstrate that basaltic melt is present beneath the East Pacific Rise spreading center in a broad region several hundred kilometers across and extending to depths greater than 100 kilometers, not just in a narrow region of high melt concentration beneath the spreading center, as predicted by some models. The structure of the ridge system is strongly asymmetric: mantle densities and seismic velocities are lower and seismic anisotropy is stronger to the west of the rise axis.

  19. An Idea for an Active Seismic Experiment on Mars in 2008

    NASA Technical Reports Server (NTRS)

    Lognonne, Ph.; Banerdt, B.; Giardini, D.; Costard, F.

    2001-01-01

    The detection of liquid water is of prime interest and should have deep implications in the understanding of the Martian hydrological cycle and also in exobiology. In the frame of the 2007 joint CNES-NASA mission to Mars, a set of 4 NETLANDERS developed by an European consortium is expected to be launched in June 2007. We propose to use a second spacecraft going or landing to Mars to release near one of the Netlander a series of artificial metallic meteorites, in order to perform an active seismic experiment providing a seismic profile of the crust and subsurface.

  20. Passive seismic monitoring of hydraulic fracture experiments at the Multiwell Experiment site

    SciTech Connect

    Thorne, B.J.; Morris, H.E.

    1988-08-01

    Redesign of hardware, software, and data-reduction techniques associated with the Sandia National Laboratories' Borehole Seismic System (BSS) have made possible better estimates of hydraulic fracture geometry at the Multiwell Experiment (MWX) site. The redesigned system now incorporates four geophones per axis and provides up to 112 dB of downhole gain, for 100 times the sensitivity of the original system. Improved signal-to-noise ratios, extended frequency response and increased digitization rates have made possible the acquisition and processing of data which were previously inaccessible. A maximum likelihood event location scheme, which incorporates an algorithm based on the use of spherical statistics, is used to compute the location of microseismic events and error estimates for these locations. Accuracy estimates for the redesigned system, based on the ability to locate perforation shots, indicates a 25 ft (7.6 m) uncertainty in the location of individual microseismic events using data from two BSS receivers. This resulted in a high level of confidence in determination of the azimuth of the November 1, 1986, hydraulic fracture in the Fluvial B sandstone. A reasonable determination of the azimuth, propped wing length and height for the September 23, 1987, hydraulic fracture in the Fluvial E sandstone was possible using data from only one BSS receiver. 15 refs., 32 figs., 6 tabs.

  1. Impact of Petrophysical Experiments on Quantitative Interpretation of 4D Seismic Data at Ketzin, Germany

    NASA Astrophysics Data System (ADS)

    Ivanova, A.; Lueth, S.

    2015-12-01

    Petrophysical investigations for CCS concern relationships between physical properties of rocks and geophysical observations for understanding behavior of injected CO2 in a geological formation. In turn 4D seismic surveying is a proven tool for CO2 monitoring. At the Ketzin pilot site (Germany) 4D seismic data have been acquired by means of a baseline (pre-injection) survey in 2005 and monitor surveys in 2009 and 2012. At Ketzin CO2 was injected in supercritical state from 2008 to 2013 in a sandstone saline aquifer (Stuttgart Formation) at a depth of about 650 m. The 4D seismic data from Ketzin reflected a pronounced effect of this injection. Seismic forward modeling using results of petrophysical experiments on two core samples fromthe target reservoir confirmed that effects of the injected CO2 on the 4D seismic data are significant. The petrophysical data were used in that modeling in order to reflect changes due to the CO2 injection in acoustic parameters of the reservoir. These petrophysical data were further used for a successful quantitative interpretation of the 4D seismic data at Ketzin. Now logs from a well (drilled in 2012) penetrating the reservoir containing information about changes in the acoustic parameters of the reservoir due to the CO2 injection are available. These logs were used to estimate impact of the petrophysical data on the qualitative and quantitative interpretation of the 4D seismic data at Ketzin. New synthetic seismograms were computed using the same software and the same wavelet as the old ones apart from the only difference and namely the changes in the input acoustic parameters would not be affected with any petrophysical experiments anymore. Now these changes were put in computing directly from the logs. In turn the new modelled changes due to the injection in the newly computed seismograms do not include any effects of the petrophysical data anymore. Key steps of the quantitative and qualitative interpretation of the 4D seismic

  2. Culturally specific interventions for African American smokers: an efficacy experiment.

    PubMed

    Webb, Monica S

    2009-09-01

    This pilot study sought to dismantle the efficacy of culturally specific print materials for smoking cessation. Two-hundred sixty-one African American smokers were randomized into 1 of 2 conditions: standard booklet or culturally specific booklet. The content and length of the interventions were identical yet varied in their degree of cultural specificity. Three-month follow-up assessments were completed by 70% (N = 183) of participants. Dependent variables included content evaluation, readiness to quit smoking, and actual behavior change. Evidence suggested that the culturally specific material was more effective at capturing attention, providing encouragement and gaining interest compared to standard materials; however, greater credibility was found for standard materials. In addition, greater readiness to quit and more 24-hour quit attempts were found in the standard condition. No differences were found in abstinence rates. In conclusion, culturally specific interventions may be preferred over standard approaches among African American smokers. Culturally specific approaches, however, may not result in greater behavior change. Implications for written interventions and cultural specificity are discussed. PMID:19806851

  3. The Millikan shaking experiments and high-frequency seismic wave propagation in Southern California

    NASA Astrophysics Data System (ADS)

    Tanimoto, Toshiro; Okamoto, Taro

    2014-08-01

    In order to study high-frequency seismic wave propagation, seismic wavefields generated by resonant-shaking experiments of the Millikan Library, on the campus of California Institute Technology (Pasadena, California, USA), were analysed. Because the resonant shaking frequencies are 1.12 Hz (the east-west direction) and 1.64 Hz (the north-south direction), this active-source experiment can provide opportunities for studying high-frequency seismic wave propagation in Southern California. Because they are very narrow frequency band data, the analyses must be quite different from ordinary time-domain analyses. We show, theoretically, that the signals must be dominated by surface waves. Adopting this surface wave assumption, we proceed to make two separate analyses, one on spectral amplitude and the other on phase. We present a new method to derive group velocity from phase based on the cross correlations between the station in the Millikan Library (MIK) and stations in the regional network. Our results support that an active-source experiment by resonant shaking of a building is a feasible approach for high-frequency seismic wave studies.

  4. Experiences of African Students in Predominantly White Institutions: A Literature Overview

    PubMed Central

    McCauley, Kay

    2016-01-01

    The objective of this paper is to examine research conducted on the experiences of African health sciences students in predominantly white higher education institutions/environments. The main elements of cross-cultural adaptation models were adopted to discuss the amalgamated themes under the auspices of adjustment, integration, and conditioning. The overview revealed that African students encounter unique experiences, with isolation and “feeling different” being commonly mentioned. Recommendations for future research are presented, including programmatic implications for higher education and student affairs professionals. PMID:27525115

  5. Martian Ambient Seismic Noise: from the first modeling to the future data of the InSight Seismic experiment.

    NASA Astrophysics Data System (ADS)

    Lognonne, P. H.; Banerdt, W. B.; Mimoun, D.; Kobayashi, N.; Panning, M. P.; Pike, W. T.; Giardini, D.; Christensen, U. R.; Nishikawa, Y.; Murdoch, N.; Kawamura, T.; Kedar, S.; Spiga, A.

    2014-12-01

    The InSight NASA Discovery mission is expected to deploy a 3 axis VBB and a 3 axis SP seismometer on Mars by late september 2016. This seismic station will explore the Martian ambient noise, in addition to more classical science goals related to the detection of Marsquakes, Meteoritic Impacts and Tides. Mars, in contrast with the Earth (with both atmosphere and ocean) and the Moon (with no atmosphere nor ocean) is expected to have ambient noise only related to its atmosphere. Mars seismic data are therefore expecting to reveal the atmospheric coupling for a different atmospheric dynamics than Earth, especially in the 0.1-1 Hz bandwidth, dominated by oceanic microseisms on Earth. We rapidly present the expected performances of the SEIS experiment onboard InSight. This experiment is based on two 3 axis seismometers, one covering the tide and low seismic frequencies (up to 10 Hz) and a second one covering the high frequencies (from 0.1 Hz to 50 Hz). Both sensors are mounted on a sensors plateform, deployed by a robotic arm 1-2 meters from the lander and covered by thermal protection and a wind protection. The expected performances indicates that signal as low as 10**(-9) m/s**2/Hz**(1/2) will be detected in the 0.005-2 Hz bandwidth. We then focus on the modeling of this ambient atmospheric noise.This modeling has been done not only from constraints gathered by the atmospheric sensors of previous Mars missions (e.g. Viking and Pathfinder) but also by numerical modeling of the atmospheric perturbations, both at global scale and mesoscale. Theoretical estimation of the ambient noise has then been obtained for the pressure-correlated surface loading and the stochastic excitation of surface waves, at both long and very long period (e.g. Mars hum) and at medium or short period (e.g. regional and local generated surface waves). Results shows that most of these source of ambient noise will be detected, likely during the day for those generated locally and possibly during the

  6. A wide-angle seismic survey of the Hecataeus Ridge, south of Cyprus: a microcontinental block from the African plate docked in a subduction zone?

    NASA Astrophysics Data System (ADS)

    Rahimi, Ayda; Welford, Kim; Hall, Jeremy; Hübscher, Christian; Louden, Keith; Ehrhardt, Axel

    2013-04-01

    Cyprus lies at the southern edge of the Aegean-Anatolian microplate, caught in the convergence of Africa and Eurasia. Subduction of the African plate below Cyprus has probably ceased and this has been attributed to the docking in the subduction zone of the Eratosthenes Seamount microcontinental fragment on the northern edge of the African plate. In early 2010, on R.V. Maria S. Merian, we conducted a wide-angle seismic survey to test the hypothesis that the Hecataeus Ridge, another possible microcontinental block lying immediately offshore SE Cyprus, might be related to an earlier docking event. The upper crust of southern Cyprus is dominated by ophiolites, with seismic velocities of up to 7 km s-1. A wide angle seismic profile along Hecataeus Ridge was populated with 15 Canadian and German ocean-bottom seismographs at 5 km intervals and these recorded shots from a 6000 cu. in. air gun array, fired approximately every 100 m. Rough topography of the seabed has made picking of phases and their modelling a demanding task. Bandpass and coherency filtering have enabled us to pick phases out to around 80 km. Tomographic inversion of short-range first arrivals provided an initial model of the shallow sub-seabed structure. Forward modelling by ray-tracing, using the code of Zelt and Smith, was then used to model crustal structure down to depths of around 20 km, with occasional evidence of reflections from deeper boundaries (Moho?). Modelling results provide good control on P-wave velocities in the top 20 km and some indications of deeper events. There is no evidence of true velocities approaching 7 km/s in the top 20 km below the Ridge that might indicate the presence of ophiolitic rocks. Regional gravity and magnetic field data tend to support this proposition. We thus conclude that Hecataeus Ridge is not composed of characteristically ophiolitic, Cyprus (upper plate) crust, and it might well be derived from the African (lower) plate.

  7. Caregiver experiences of discrimination and african american adolescents' psychological health over time.

    PubMed

    Ford, Kahlil R; Hurd, Noelle M; Jagers, Robert J; Sellers, Robert M

    2013-01-01

    The present study examined the effect of caregivers' experiences of racial discrimination on their adolescent children's psychological functioning among a sample of 264 African American dyads. Potential relations between caregiver discrimination experiences and a number of indicators of adolescents' (aged 12-17) psychological functioning over time were examined. It was found that caregiver discrimination experiences were positively related to adolescents' symptoms of depression and negatively related to their psychological well-being. Additional analysis revealed interactions between the effects of caregiver discrimination experiences and family income on all 3 outcomes. Greater caregiver discrimination experiences and lower family income were risk factors for the youth in the sample. These findings underscore the deleterious consequence of caregivers' discrimination experiences on African American youth's psychological health.

  8. Capacity development for health research in Africa: experiences managing the African Doctoral Dissertation Research Fellowship Program

    PubMed Central

    2010-01-01

    Africa's progress depends on her capacity to generate, adapt, and use scientific knowledge to meet regional health and development needs. Yet, Africa's higher education institutions that are mandated to foster this capacity lack adequate resources to generate and apply knowledge, raising the need for innovative approaches to enhance research capacity. In this paper, we describe a newly-developed program to support PhD research in health and population sciences at African universities, the African Doctoral Dissertation Research Fellowship (ADDRF) Program. We also share our experiences implementing the program. As health research capacity-strengthening in Africa continues to attract attention and as the need for such programs to be African-led is emphasized, our experiences in developing and implementing the ADDRF offer invaluable lessons to other institutions undertaking similar initiatives. PMID:20587016

  9. Joint seismic-geodynamic-mineral physical modelling of African geodynamics: A reconciliation of deep-mantle convection with surface geophysical constraints

    SciTech Connect

    Forte, A M; Quere, S; Moucha, R; Simmons, N A; Grand, S P; Mitrovica, J X; Rowley, D B

    2008-08-22

    Recent progress in seismic tomography provides the first complete 3-D images of the combined thermal and chemical anomalies that characterise the unique deep mantle structure below the African continent. With these latest tomography results we predict flow patterns under Africa that reveal a large-scale, active hot upwelling, or superplume, below the western margin of Africa under the Cape Verde Islands. The scale and dynamical intensity of this West African superplume (WASP) is comparable to that of the south African superplume (SASP) that has long been assumed to dominate the flow dynamics under Africa. On the basis of this new tomography model, we find the dynamics of the SASP is strongly controlled by chemical contributions to deep mantle buoyancy that significantly compensate its thermal buoyancy. In contrast, the WASP appears to be entirely dominated by thermal buoyancy. New calculations of mantle convection incorporating these two superplumes reveal that the plate-driving forces due to the flow generated by the WASP is as strong as that due to the SASP. We find that the chemical buoyancy of the SASP exerts a strong stabilising control on the pattern and amplitude of shallow mantle flow in the asthenosphere below the southern half of the African plate. The asthenospheric flow predictions provide the first high resolution maps of focussed upwellings that lie below the major centres of Late Cenozoic volcanism, including the Kenya domes and Hoggar massif that lies above a remnant plume head in the upper mantle. Inferences of sublithospheric deformation from seismic anisotropy data are shown to be sensitive to the contributions of chemical buoyancy in the SASP.

  10. Seismic images of the Brooks Range fold and thrust belt, Arctic Alaska, from an integrated seismic reflection/refraction experiment

    USGS Publications Warehouse

    Levander, A.; Fuis, G.S.; Wissinger, E.S.; Lutter, W.J.; Oldow, J.S.; Moore, T.E.

    1994-01-01

    We describe results of an integrated seismic reflection/refraction experiment across the Brooks Range and flanking geologic provinces in Arctic Alaska. The seismic acquisition was unusual in that reflection and refraction data were collected simultaneously with a 700 channel seismograph system deployed numerous times along a 315 km profile. Shot records show continuous Moho reflections from 0-180 km offset, as well as numerous upper- and mid-crustal wide-angle events. Single and low-fold near-vertical incidence common midpoint (CMP) reflection images show complex upper- and middle-crustal structure across the range from the unmetamorphosed Endicott Mountains allochthon (EMA) in the north, to the metamorphic belts in the south. Lower-crustal and Moho reflections are visible across the entire reflection profile. Travel-time inversion of PmP arrivals shows that the Moho, at 33 km depth beneath the North Slope foothills, deepens abruptly beneath the EMA to a maximum of 46 km, and then shallows southward to 35 km at the southern edge of the range. Two zones of upper- and middle-crustal reflections underlie the northern Brooks Range above ~ 12-15 km depth. The upper zone, interpreted as the base of the EMA, lies at a maximum depth of 6 km and extends over 50 km from the range front to the north central Brooks Range where the base of the EMA outcrops above the metasedimentary rocks exposed in the Doonerak window. We interpret the base of the lower zone, at ~ 12 km depth, to be from carbonate rocks above the master detachment upon which the Brooks Range formed. The seismic data suggest that the master detachment is connected to the faults in the EMA by several ramps. In the highly metamorphosed terranes south of the Doonerak window, the CMP section shows numerous south-dipping events which we interpret as a crustal scale duplex involving the Doonerak window rocks. The basal detachment reflections can be traced approximately 100 km, and dip southward from about 10-12 km

  11. Community among African American Students on Small, Predominantly White Campuses: The Unforeseen "Minority within a Minority" Experience.

    ERIC Educational Resources Information Center

    Littleton, Robert A.

    2003-01-01

    Describes the experiences of 16 African American students who attended four small, predominantly White colleges in the Southern Appalachian region of the United States. The African American community at these small colleges can sometimes be an unforeseen cultural experience especially for Black male and female nonathletes. Qualitative methodology…

  12. African American Women Coping with the Lived Experiences of Limited Mental Healthcare Access in Rural North Carolina

    ERIC Educational Resources Information Center

    Lesane, Everick S.

    2013-01-01

    This study examined the impact of lived experiences among African American women with limited mental healthcare access in rural North Carolina. The research examined how those lived experiences-due to limited transportation, low socioeconomic status, and limited healthcare access-further exacerbate emotional challenges among African American…

  13. The Lived Experience of the Adult African American Female Who Has Lived in Multiple Foster Care Placements

    ERIC Educational Resources Information Center

    Johnson, Avonda C.

    2012-01-01

    The purpose of the study was to examine and describe the lived experiences of the adult African American woman who had lived in multiple foster care placements. Eleven adult African American women ages 22-25 participated in semi-structured, face-to-face interviews to tell their stories and provide data of the memories of the experience. The…

  14. Striving to Be "in" the Profession and "of" It: The African American Experience in Physical Education and Kinesiology

    ERIC Educational Resources Information Center

    Wiggins, David K.; Wiggins, Brenda P.

    2011-01-01

    This study analyzes the experiences of African Americans in the physical education and kinesiology profession since the late 1850s. Using a variety of primary and secondary source material, we place special emphasis on the experiences of African American physical educators in higher education and in the American Alliance for Health, Physical…

  15. Deep seismic refraction experiment in northeast Brazil: New constraints for Borborema province evolution

    NASA Astrophysics Data System (ADS)

    Lima, Marcus Vinicius A. G. de; Berrocal, Jesus; Soares, José E. P.; Fuck, Reinhardt A.

    2015-03-01

    The Borborema Province of northeastern Brazil is a major Proterozoic crustal province that, until now, has never been explored using deep crustal seismic methods. Here are reported the first results obtained from a high-quality seismic refraction/wide-angle reflection profile that has defined the internal seismic velocity structure and thickness of the crust in this region. Almost 400 recording stations were deployed in the Deep Seismic Refraction (DSR) experiment through an NW-SE ca. 900 km linear array and 19 shots were exploded at every 50 km along the line. Data from the 10 southeastern most shots of the seismic profile were processed in this work. The main features and geological structures crossed by the studied portion of the profile belong to the so-called Central Sub-province of the Borborema tectonic province. The crustal model obtained is compatible with a typical structure of extended crust. The model was essentially divided into three layers: upper crust, lower crust, and a half-space represented by the shallower portion of the mantle. The Moho is an irregular interface with depth ranging between 31.7 and 34.5 km, and beneath the Central Sub-province it varies from 31.5 to 33 km depth, where its limits are related to major crustal discontinuities. The distribution of velocities within the crust is heterogeneous, varying vertically from 5.7 to 6.3 km/s in the upper crust and from 6.45 to 6.9 km/s in the lower crust. From the average crustal velocity distribution it is evident that the Central Sub-province has seismic characteristics different from neighboring domains. The crust is relatively thin and crustal thickness variations in the profile are subtle due to stretching that occurred in the Cretaceous, during the fragmentation of Pangaea, opening of the South Atlantic Ocean and separation of South America from Africa.

  16. Toddler Feeding: Expectations and Experiences of Low-Income African American Mothers

    ERIC Educational Resources Information Center

    Horodynski, Mildred A.; Brophy-Herb, Holly; Henry, Michelle; Smith, Katharine A.; Weatherspoon, Lorraine

    2009-01-01

    Objective: To ascertain maternal expectations and experiences with mealtimes and feeding of toddlers among low-income African American mothers in two mid- to large-size cities in the United States. Design: Qualitative focus group study. Setting: Two Early Head Start programme sites in a Midwestern state which serve low income families. Method:…

  17. Educational Change in Post-Conflict Contexts: Reflections on the South African Experience 20 Years Later

    ERIC Educational Resources Information Center

    Christie, Pam

    2016-01-01

    Reflecting on South African experience, this paper develops an analytical framework using the work of Henri Lefebvre and Nancy Fraser to understand why socially just arrangements may be so difficult to achieve in post-conflict reconstruction. The paper uses Lefebvre's analytic to trace three sets of entangled practices…

  18. Cooperative Policies and African International Students: Do Policy Spirits Match Experiences?

    ERIC Educational Resources Information Center

    McLellan, Carlton E.

    2009-01-01

    This paper explores the policy implications of experiences of African international students (AIS) studying at post-apartheid South Africa universities. It argues that given the spirit and tone of continental, regional, and domestic policies to which South Africa has committed that at the very least there is an implicit expectation of…

  19. Relationships between Discretionary Time Activities, Emotional Experiences, Delinquency and Depressive Symptoms among Urban African American Adolescents

    ERIC Educational Resources Information Center

    Bohnert, Amy M.; Richards, Maryse; Kohl, Krista; Randall, Edin

    2009-01-01

    Using the Experience Sampling Method (ESM), this cross-sectional study examined mediated and moderated associations between different types of discretionary time activities and depressive symptoms and delinquency among a sample of 246 (107 boys, 139 girls) fifth through eighth grade urban African American adolescents. More time spent in passive…

  20. African-American School Counselors in Majority School Districts: A Qualitative Perspective of Their Lived Experiences

    ERIC Educational Resources Information Center

    Wingate, Crystal Nicole

    2011-01-01

    This dissertation will focus on the lived experiences of African-American school counselors in majority school districts and the lack of retention among this population. The lack of retention and representation of ethnic minorities in the workforce has been the subject of much discussion throughout the United States (Ingersoll, 2004). The…

  1. Resilience Post Tenure: The Experience of an African American Woman in a PWI

    ERIC Educational Resources Information Center

    Behar-Horenstein, Linda S.; West-Olatunji, Cirecie A.; Moore, Thomas E.; Houchen, Deidre F.; Roberts, Kellie W.

    2012-01-01

    The purpose of this study was: 1) to explore the pre-tenure experiences of an African American female faculty member in a counselor education program; and 2) to compare the themes that ascended from a precursor study to the current one. By using critical ethnography and case study format, this research gave voice to the participant by prompting…

  2. Underserved, Underrepresented, Unprepared: Experiences of African American Females in Community College with Barriers to Academic Success

    ERIC Educational Resources Information Center

    Jobe, LaWanda D.

    2013-01-01

    African American women are enrolling and returning to college in large numbers across many community college campuses, especially those women who would be characterized as nontraditional students. This qualitative study examined and analyzed the experiences, stresses, and coping mechanisms of first generation, nontraditional, single parent,…

  3. African American College Students' Experience of Racial Discrimination and the Role of College Hassles

    ERIC Educational Resources Information Center

    Banks, Kira Hudson

    2010-01-01

    The current study examines the relationship between racial discrimination and depressive symptoms. In particular, it investigated whether college hassles moderated or mediated the relationship. Participants included 194 African American students from a large, Midwestern, state university. Participants provided self-report of their experience of…

  4. Black South Africans in the United States: An Analysis of Their Educational and Practical Training Experiences.

    ERIC Educational Resources Information Center

    Crawford, Beth S.; Kreidle, Ann M.

    A study was done of the experiences of Black South Africans who came to the United States for education and training. The research studied 140 individuals who participated in two programs between 1980 and 1991. Data were collected from the student files and from standard university data from "Profiles of American Colleges" by Barron's Educational…

  5. Ethical issues in genomic research on the African continent: experiences and challenges to ethics review committees.

    PubMed

    Ramsay, Michèle; de Vries, Jantina; Soodyall, Himla; Norris, Shane A; Sankoh, Osman

    2014-01-01

    This is a report on a workshop titled 'Ethics for genomic research across five African countries: Guidelines, experiences and challenges', University of the Witwatersrand, Johannesburg, South Africa, 10 and 11 December 2012. The workshop was hosted by the Wits-INDEPTH partnership, AWI-Gen, as part of the H3Africa Consortium.

  6. Sub-Saharan African Students and Their Experiences in American Higher Education

    ERIC Educational Resources Information Center

    Osikomaiya, Olujide

    2014-01-01

    The purpose of this research project is to study the experiences of Sub-Saharan African students, who have earned professional degrees from American institutions and are currently living in the United States. Acculturative stressors have been identified by researchers as predictors of loneliness, depression, homesickness, and poor mental health…

  7. Missed Opportunities: Examining the Literacy Experiences of African American Students Displaced by Hurricane Katrina

    ERIC Educational Resources Information Center

    Pollard, Tamica McClarty

    2011-01-01

    The purpose of this study was to examine how five African American middle school students, who were displaced by Hurricane Katrina represent their literacy experiences before, during, and after their displacement. Specifically, the two research questions were: (a) What are the stories that these middle school students tell about their lives,…

  8. African American Students in Counselor Education Programs: Perceptions of Their Experiences

    ERIC Educational Resources Information Center

    Henfield, Malik S.; Owens, Delila; Witherspoon, Sheila

    2011-01-01

    The authors explored 11 African American doctoral students' perceptions of their experiences in counselor education programs, and their findings are presented. Using a phenomenological methodological framework, the authors investigated the various systems of support that students use as they navigate their respective programs. Human agency was the…

  9. The Road Not Taken: Two African-American Girls' Experiences with School Mathematics

    ERIC Educational Resources Information Center

    Lim, Jae Hoon

    2008-01-01

    This article is a cross-case study exploring two young African-American adolescent girls' experiences with school mathematics and the impact of the socio-cultural context upon their motivation and mathematical identity. Based on repeated in-depth interviews and ethnographic observation of their mathematics classroom, the researcher portrays…

  10. Problematic Situations Associated with Dating Experiences and Relationships among Urban African American Adolescents: A Qualitative Study

    ERIC Educational Resources Information Center

    Sullivan, Terri N.; Erwin, Elizabeth H.; Helms, Sarah W.; Masho, Saba W.; Farrell, Albert D.

    2010-01-01

    This qualitative study focused on the identification of problem situations associated with adolescent dating experiences and relationships, including those that placed youth at risk for dating violence perpetration or victimization. Interviews were conducted with 44 African American middle and high school students in an urban school system.…

  11. Racial Identity, Language Attitudes and Educational Experiences: The Voices of African American College Students

    ERIC Educational Resources Information Center

    Stewart, Gail A.

    2012-01-01

    The current study examines the language attitudes, racial identity and educational experiences of 75 African American university and community college students. This study is motivated by the hypothesis that the power of language attitudes dictates, to a large extent, the language one speaks, which is intimately tied to one's sense of…

  12. Illuminating the Experiences of African-American Nursing Faculty Seeking Employment in Higher Education in Nursing

    ERIC Educational Resources Information Center

    Loyd, Vanessa

    2015-01-01

    This study explored and described the experience of female African-American nursing faculty seeking employment in higher education in nursing. The lack of diversity in the nursing workforce has been attributed as a major underlying cause of disparity in healthcare in the United States. The importance of increasing the number of minority nursing…

  13. In Their Own Voices: Adolescent African American Males' Experiences of the Achievement Gap

    ERIC Educational Resources Information Center

    Moon, Natasha S.; Singh, Anneliese A.

    2015-01-01

    The authors use a phenomenological research tradition grounded in CRT tenets to describe the daily lived experiences that 12 male African American youth had in relation to the achievement gap. Researchers collected individual semi-structured interviews and focus group data related to the study phenomenon. There were five themes identified in…

  14. On the Outside Looking in: An African American Family's Experience in an Individualized Education Plan Meeting

    ERIC Educational Resources Information Center

    Angelov, Azure D. S.; Anderson, Sheri L.

    2012-01-01

    The current laws that mandate special education originated through the advocacy of families (Turnbull & Turnbull, 1990). Over the years, families have challenged the system to provide free and appropriate public educations for their children. We share, through qualitative measures, the experiences of one African American family and the educators…

  15. Personal, Professional, and Sociocultural Experiences of African American Female School Leaders

    ERIC Educational Resources Information Center

    Robinson, Armentress D.

    2014-01-01

    The purpose of this phenomenological study was to explore and gain an in-depth understanding of the personal, professional, and sociocultural experiences of ten African American female school leaders serving as assistant principals, principals, and central office administrators in four suburban school districts in the southeast region of the…

  16. Ring of Silence: African American Women's Experiences Related to Their Breasts and Breast Cancer Screening

    ERIC Educational Resources Information Center

    Thomas, Eileen

    2006-01-01

    The purpose of this study was to explore women's memories and feelings concerning their breasts and breast cancer screening experiences in relation to their current breast cancer screening behaviors. Twelve African American women shared stories that were generated in written narratives and individual interviews. Two core themes emerged from the…

  17. Advancing Explosion Source Theory through Experimentation: Results from Seismic Experiments Since the Moratorium on Nuclear Testing

    NASA Astrophysics Data System (ADS)

    Bonner, J. L.; Stump, B. W.

    2011-12-01

    On 23 September 1992, the United States conducted the nuclear explosion DIVIDER at the Nevada Test Site (NTS). It would become the last US nuclear test when a moratorium ended testing the following month. Many of the theoretical explosion seismic models used today were developed from observations of hundreds of nuclear tests at NTS and around the world. Since the moratorium, researchers have turned to chemical explosions as a possible surrogate for continued nuclear explosion research. This talk reviews experiments since the moratorium that have used chemical explosions to advance explosion source models. The 1993 Non-Proliferation Experiment examined single-point, fully contained chemical-nuclear equivalence by detonating over a kiloton of chemical explosive at NTS in close proximity to previous nuclear explosion tests. When compared with data from these nearby nuclear explosions, the regional and near-source seismic data were found to be essentially identical after accounting for different yield scaling factors for chemical and nuclear explosions. The relationship between contained chemical explosions and large production mining shots was studied at the Black Thunder coal mine in Wyoming in 1995. The research led to an improved source model for delay-fired mining explosions and a better understanding of mining explosion detection by the International Monitoring System (IMS). The effect of depth was examined in a 1997 Kazakhstan Depth of Burial experiment. Researchers used local and regional seismic observations to conclude that the dominant mechanism for enhanced regional shear waves was local Rg scattering. Travel-time calibration for the IMS was the focus of the 1999 Dead Sea Experiment where a 10-ton shot was recorded as far away as 5000 km. The Arizona Source Phenomenology Experiments provided a comparison of fully- and partially-contained chemical shots with mining explosions, thus quantifying the reduction in seismic amplitudes associated with partial

  18. Noma: experiences with a microvascular approach under West African conditions.

    PubMed

    Giessler, Goetz A; Schmidt, Andreas B

    2003-09-15

    Noma (cancrum oris) is a serious ulcerating disease that generally begins in the gingival sulcus of children. One of the main areas of prevalence today is West Africa. If noma is survived, it results in disfiguring midfacial defects and intense scarring. Oral incompetence is often combined with trismus resulting from scar formation or bony fusion between the maxilla and the mandible. Reconstructive approaches with pedicled flaps from the head or shoulder area for closure of the outer defects have been prone to donor-site complications or have not properly addressed the trismus, leading to high recurrence rates. During three West African Interplast missions, a single-stage procedure was developed for reconstruction of the inner and outer linings of the oral, nasal, and paranasal cavities, with restoration of jaw function. The procedure consists of radical scar excision, placement of an external distractor for mouth opening, and primary closure of the defect with a folded free parascapular flap for full-thickness coverage. Twenty-three patients with various noma-related defects were treated with this procedure; two cases are described in detail. This combined treatment can be a safe successful procedure for patients with noma, especially those with severe soft-tissue destruction and profound trismus, even under demanding surgical conditions.

  19. DOE Non-Proliferation Experiment includes seismic data

    NASA Astrophysics Data System (ADS)

    Zucca, Jay

    The U.S. Department of Energy detonated approximately 1.29 million kg of a commercial blasting agent, based on ammonium nitrate and fuel oil (ANFO), at the Nevada Test Site (NTS) on September 22, 1993, at 00:01.080 a.m. Pacific Daylight Time. The blasting agent was emplaced in a cylindrical chamber, approximately 15.2 m in diameter × 5.5 m high, located at 37.20193°N and 116.20986°E in a Rainier Mesa tunnel, 390 m underground. Code-named the Non-Proliferation Experiment (NPE), the explosion had an energy release of approximately 1 kt (1 kiloton = 4.186×1012 joules).

  20. The structure and subsidence of Rockall Trough from two-ship seismic experiments

    SciTech Connect

    Joppen, M.; White, R.S. )

    1990-11-10

    Coincident multichannel seismic reflection and refraction profiles acquired northwest of Britain during a two-ship seismic experiment in the southern Rockall Trough provide evidence for a thin (6 km) syn-rift crust below Rockall Trough. The variation of seismic velocity with depth is consistent with either oceanic crust similar to that found in other parts of the North Atlantic or with thinned continental crust heavily intruded by syn-rift igneous rocks. The syn-rift crust beneath Rockall Trough is now buried by nearly 5 km of sediments that are intruded by Tertiary volcanics varying in extent from isolated sills to a large sill complex extending 100 km laterally. The basement imaged on seismic profiles exhibits a band of subhorizontal reflectors that extend laterally over distances of up to 40 km which they interpret as sediments intercalated with submarine lava flow generated during the opening of the Trough. Estimates of stretching from crustal thinning and from subsidence indicate that Rockall Trough has undergone extensive rifting ({beta} > 6). Upwelling asthenosphere beneath the thinned lithosphere generated at least 1-3 km thickness of melt as it decompressed. The molten rock rose upward from the mantle until it was in part extruded as lava flows and in part intruded into the crust.

  1. African-American Women’s Perceptions and Experiences About Breastfeeding

    PubMed Central

    Obeng, Cecilia S.; Emetu, Roberta E.; Curtis, Terry J.

    2015-01-01

    There are health benefits to breastfeeding for both mothers and their children. The preventive health effects of breastfeeding continue into adulthood, lowering rate of various chronic illnesses. African-American women, especially of lower socioeconomic status, are less likely to breastfeed in comparison to their racial and ethnic counterparts. The purpose of this study is to explore how African-American women experience breastfeeding in the early stages of postpartum care. Two focus groups (N = 20, 10 in each group) were conducted with African-American mothers. Results revealed that participants felt that there were health benefits to breastfeeding, and organizations such as Women, Infants, and Children (WIC) provided support. However, participants stated that lack of information, negative perceptions, and unforeseen circumstances were barriers to breastfeeding. This study proposes support and interventions for this group to increase breastfeeding among this population. PMID:26734597

  2. Coparenting experiences in African American families: an examination of single mothers and their nonmarital coparents.

    PubMed

    Gonzalez, Michelle; Jones, Deborah; Parent, Justin

    2014-03-01

    African American youth from single-mother homes continue to be overrepresented in statistics on risk behavior and delinquency, a trend that many be attributed to father-absence, socioeconomic disadvantage, and compromises in parenting more typical of single than two-parent families. Yet, this risk-focused perspective ignores a long-standing strength of the African American community, the involvement and potential protective impact of extended family members in childrearing. This study describes the experiences of 95 African American single mothers and their nonmarital coparents who participated in a study of African American single-mother families with an 11-16-year-old child. Specifically, the study examines: (a) the extent to which nonmarital coparents are involved in childrearing; (b) the relative levels of risk (i.e., depression, mother-coparent conflict) and protective (i.e., parenting) associated with maternal and coparent involvement; and (c) how similarly and/or differently coparent and mother variables operate with regard to youth externalizing problems. Findings reveal that a range of family members and other adults actively participate in childrearing in African American single-mother families, coparents do not differ from mothers on certain study variables (i.e., depression and mother-coparent conflict) but do for others (parenting), and coparent involvement is associated with youth adjustment in ways that are similar to our more established understanding of maternal involvement. The potential clinical implications of the findings are discussed and future research directions are highlighted. PMID:24479612

  3. Racism experiences and psychological functioning in African American college freshmen: is racial socialization a buffer?

    PubMed

    Bynum, Mia Smith; Burton, E Thomaseo; Best, Candace

    2007-01-01

    Previous research has documented the negative effects of racism on the psychological health of African Americans. However, consideration of racial socialization as a potential buffer against racism experiences has received limited attention. The present study investigated whether two types of parental racial socialization messages reduced the impact of racism on psychological functioning in a sample of 247 African American college freshmen (M=18.30). Results indicated that students who reported more racism experiences also had poorer levels of psychological functioning as indicated by higher levels of psychological stress and psychological distress. Parental messages emphasizing the use of African American cultural resources to cope with racism reduced the impact of racism on psychological stress only. Cultural pride messages predicted less psychological distress while messages emphasizing the use of cultural resources predicted greater psychological distress. However, neither message type moderated the relationship between racism experiences and psychological distress. These results suggest that racial socialization messages have complex relations to psychological functioning in African American college students.

  4. Masculinities fathering and health: the experiences of African-Caribbean and white working class fathers.

    PubMed

    Williams, Robert Alan

    2007-01-01

    There is a developing body of research that investigates the links between masculinities and men's health experiences, but the links between masculinities and the health of fathers has been a neglected focus for research in the UK. This paper presents some of the findings drawn from a parent study which investigated African-Caribbean and white working class fathers' experiences of fathering, health and social connectedness. Data are drawn from interviews with 13 men (6 African-Caribbean and 7 White working class) living in a city in the West Midlands area of the UK. In this paper, I analyse and discuss African-Caribbean and white working class fathers' stories about the meaning of health, the influences upon their health, and their health practices. It was found that for the African-Caribbean fathers specifically, anticipated or perceived racist prejudice, abuse or discrimination influenced their health experiences. However, the meaning of health for both ethnic groups of fathers was as functional capacity, that is health was an asset that allowed fathers to meet the obligations of paid work and fathering. These obligations were also associated with a restricted sense of personal agency for the men interviewed, and the associated constraints were linked to transgressive consumption of alcohol, food and tobacco. In addition, fathers were also involved in solitary ways of dealing with their vulnerability, vulnerability that was associated with fathers' health concerns, and other difficult life experiences. Fathers' solitary experiences of vulnerability were also mediated by hegemonic forms of masculinity. Nevertheless, the experience of fathering within the lifecourse influenced men's health experiences: reflexivity and challenges to both transgressive consumption and solitary experiences were linked to fathers' perceived obligations to children. The significance of gender, ethnicity and social class for theory and future research with working class fathers and boys

  5. Freshman-year experiences for African-American students in engineering

    NASA Astrophysics Data System (ADS)

    Chapple, Bernadette Maria

    1998-12-01

    The purpose of this study was to discover (a) why African American students choose to persist as an engineering major and (b) why students choose to leave engineering as a major. A total of 17 students from a large land-grant university participated in this study that was both quantitative and qualitative in design. This research will assist both the College of Engineering and the University in understanding the educational experiences of the matriculating African American pre-engineering student. In an effort to provide reasons and rationale for why African American engineering students choose to stay in this major and why other African American engineering student majors choose to leave, the researcher examined an undergraduate engineering program at a large land-grant institution in the South. The College of Engineering at this institution was able to institute several programs designed to increase the number of African American students choosing engineering as a major. Although initiatives for pre-collegiate students are important in the retention of African American students, it is the retention of those students once accepted into a program of study that the institution focuses on most. It is the intent of this study to offer a better understanding of such a retention initiative. Due to the decline of African American students pursuing majors in science and mathematics in general and in engineering in particular, an important research concern is to offer more insight into the experiences of the freshman engineering student in an attempt to develop fundamental reasons for why students remain in engineering and why some students leave. To assist the College of Engineering and the University in understanding the educational experiences of the matriculating African American pre-engineering student the data were collected from both a quantitative and qualitative approach. Results indicated that (a) students who chose to persist in the engineering program where

  6. Exploring Crustal Structure and Mantle Seismic Anisotropy Associated with the Incipient Southern and Southwestern Branches of the East African Rift System

    NASA Astrophysics Data System (ADS)

    Yu, Y.; Reed, C. A.; Gao, S. S.; Liu, K. H.; Massinque, B.; Mdala, H. S.; Chindandali, P. R. N.; Moidaki, M.; Mutamina, D. M.

    2014-12-01

    In spite of numerous geoscientific studies, the mechanisms responsible for the initiation and development of continental rifts are still poorly understood. The key information required to constrain various geodynamic models on rift initiation can be derived from the crust/mantle structure and anisotropy beneath incipient rifts such as the Southern and Southwestern branches of the East African Rift System. As part of a National Science Foundation funded interdisciplinary project, 50 PASSCAL broadband seismic stations were deployed across the Malawi, Luangwa, and Okavango rift zones from the summer of 2012 to the summer of 2014. Preliminary results from these 50 SAFARI (Seismic Arrays for African Rift Initiation) and adjacent stations are presented utilizing shear-wave splitting (SWS) and P-S receiver function techniques. 1109 pairs of high-quality SWS measurements, consisting of fast polarization orientations and splitting times, have been obtained from a total of 361 seismic events. The results demonstrate dominantly NE-SW fast orientations throughout Botswana as well as along the northwestern flank of the Luangwa rift valley. Meanwhile, fast orientations beneath the eastern Luangwa rift flank rotate from NNW to NNE along the western border of the Malawi rift. Stations located alongside the western Malawi rift border faults yield ENE fast orientations, with stations situated in Mozambique exhibiting more E-W orientations. In the northern extent of the study region, fast orientations parallel the trend of the Rukwa and Usangu rift basins. Receiver function results reveal that, relative to the adjacent Pan-African mobile belts, the Luangwa rift zone has a thin (30 to 35 km) crust. The crustal thickness within the Okavango rift basin is highly variable. Preliminary findings indicate a northeastward thinning along the southeast Okavango border fault system congruent with decreasing extension toward the southwest. The Vp/Vs measurements in the Okavango basin are roughly

  7. Seismic array monitoring of mortar fire during the November 2005 ARL-NATO TG-53 field experiment at YPG

    NASA Astrophysics Data System (ADS)

    Anderson, Thomas S.; Fisk, David J.; Fiori, John E.; Decato, Stephan N.; Punt, Douglas A.; Lamie, N.

    2006-05-01

    The U.S. Army Corps of Engineers Engineer Research and Development Center (ERDC) participated in a joint ARL-NATO TG-53 field experiment and data collection at Yuma Proving Ground, AZ, in early November 2005. Seismic and acoustic signatures from both muzzle blasts and impacts of small arms fire and artillery were recorded using seven seismic arrays and three acoustic arrays. Arrays composed of 12 seismic and 12 acoustic sensors each were located from 700 m to 18 km from gun positions. Preliminary analysis of signatures attributed to 60-mm, 81-mm, and 120-mm mortars recorded at a seismic-acoustic array 1.1 km from gun position are presented. Seismic and acoustic array f-k analysis is performed to detect and characterize the source signature. Horizontal seismic data are analyzed to determine efficacy of a seismic discriminant for mortar and artillery sources. Rotation of North and East seismic components to radial and transverse components relative to the source-receiver path provide maximum surface wave amplitude on the transverse component. Angles of rotation agree well with frequency-wavenumber (f-k) analysis of both seismic and acoustic signals. The spectral energy of the rotated transverse surface wave is observable on all caliber of mortars at a distance of 1.1 km and is a reliable source discriminant for mortar sources at this distance.

  8. Tackling the African "poverty trap": the Ijebu-Ode experiment.

    PubMed

    Mabogunje, Akin L

    2007-10-23

    An experiment in poverty reduction began in 1998 in the city of Ijebu-Ode, Nigeria (estimated 1999 population 163,000), where, without the remittances from relatives abroad, an estimated 90% of the population lived below the poverty line of $1.00 (U.S.) per person per day. Central to the experiment was whether poverty can be dramatically reduced through a city consultation process that seeks to mobilize the entire community along with its diaspora. With 7 years of experience, the Ijebu-Ode experiment has been successful in many ways. There is increasing evidence that poverty in the city has been reduced significantly through the microfinancing of existing and new productive activities and the estimated >8,000 jobs these activities have created. Training based on both sustainability science and technology and indigenous practitioner knowledge has been a critical factor in the establishment of cooperatives and the development of new enterprises in specialty crops, small animal, and fish production. Much of this success has been possible as a result of harnessing social capital, especially through the dynamic leadership of the traditional authorities of the city and by the provision of ample loanable funds through the National Poverty Eradication Program of the federal government. The city consultation process itself engendered a participatory focus to the experiment from the beginning and has encouraged sustainability. Yet long-term sustainability is still in question as the initial leadership needs replacement, and credit, the heart of the experiment, lacks sufficient collateral. PMID:17942687

  9. Correlates of coping with perceived discriminatory experiences among African American adolescents.

    PubMed

    Scott, Lionel D

    2004-04-01

    This study examined the relation of background and race-related factors to the use of approach and avoidance strategies to cope with perceived discriminatory experiences among a sample of African American adolescents of relative affluence ( n = 71). Results showed that gender, family structure, socioeconomic status (SES), perceived control over discriminatory experiences, discrimination distress, and racism-related socialization were significant correlates of coping with perceived discriminatory experiences. Results concerning gender, perceived control, and stress arousal were consistent with findings from the general adolescent stress and coping literature. Results concerning family structure, SES, and socialization suggest that certain factors may be very important for the positive adjustment of African American adolescents in the face of race-related adversity.

  10. African-American menthol and nonmenthol smokers: differences in smoking and cessation experiences.

    PubMed Central

    Okuyemi, Kolawole S.; Ebersole-Robinson, Maiko; Nazir, Niaman; Ahluwalia, Jasjit S.

    2004-01-01

    BACKGROUND: Despite smoking fewer cigarettes per day, African Americans have lower cessation rates and experience disproportionately higher rates of smoking-related health consequences. Because of their high preference for menthol cigarettes, it has been suggested that smoking menthol cigarettes may contribute to the excess smoking-related morbidity experienced by African Americans. Smoking menthol cigarettes could increase health risks from smoking if smokers of menthol cigarettes have lower cessation rates and thereby have longer duration of smoking compared to smokers of nonmentholated cigarettes. Few studies have examined associations between smoking of mentholated cigarettes and smoking cessation among African Americans. This study examined the smoking patterns of menthol cigarette smokers and their smoking cessation experiences. METHODS: A cross-sectional survey of 480 African-American smokers at an inner-city health center. Survey examined sociodemographics, smoking characteristics, and smoking cessation experiences of participants. Menthol smokers (n = 407) were compared to nonmenthol smokers (n = 73) in these characteristics. RESULTS: Menthol smokers were younger and more likely to smoke cigarettes with longer rod length, with filters, and those high in nicotine and tar. Although both groups did not differ by number of past quit attempts, time since most recent quit attempt was shorter for menthol smokers. The durations of most recent and longest-ever quit attempts were nonsignificantly shorter for menthol, compared to nonmenthol smokers. CONCLUSIONS: These data suggest that African-American menthol smokers are less successful with smoking cessation. Prospective studies are needed to confirm these findings and examine mechanisms underlying such differences. PMID:15481749

  11. Not Merely a Matter of Academics: Student Experiences of a South African University as Study-Abroad Destination

    ERIC Educational Resources Information Center

    Paola, R. J.; Lemmer, E. M.

    2013-01-01

    Study abroad programmes attract considerable numbers of American college students; however, very few select an African country as their study-abroad destination. This article explores the experiences of American undergraduates who made the uncommon choice of a South African university as destination for a mid-length immersion type programme. The…

  12. Teacher and Parent Perceptions of Classroom Experiences of African American Male Students in a High School Alternative Program

    ERIC Educational Resources Information Center

    Johnson, Kimberly C.

    2013-01-01

    A major concern in the public schools is the low academic achievement of African American males. This mixed methods study examined the classroom experiences of African American male students in an alternative program. The dual purpose was to investigate the teachers' perceptions and their ability to provide best learning environments for…

  13. Community among African American Students on Small, Predominantly White Campuses: The Unforeseen "Minority within a Minority" Experience

    ERIC Educational Resources Information Center

    Journal of American College Health, 2005

    2005-01-01

    Sixteen African American students participated in semi-structured, open-ended interviews about their experiences at small, predominantly white colleges in the Appalachian region. Two main themes emerged from the interviews: community among minorities and minority within a minority. The students described community among African Americans on campus…

  14. "A Fly in the Ointment": African American Male Preservice Teachers' Experiences with Stereotype Threat in Teacher Education

    ERIC Educational Resources Information Center

    Scott, Sonya V.; Rodriguez, Louie F.

    2015-01-01

    This study draws from a larger phenomenological study on African American academic persistence and career aspirations in education. This article highlights three African American males' experiences with concentrated forms of stereotype threat in teacher education. Their voices revealed dimensions of how power and privilege operate in teacher…

  15. Martian seismicity

    NASA Technical Reports Server (NTRS)

    Phillips, Roger J.; Grimm, Robert E.

    1991-01-01

    The design and ultimate success of network seismology experiments on Mars depends on the present level of Martian seismicity. Volcanic and tectonic landforms observed from imaging experiments show that Mars must have been a seismically active planet in the past and there is no reason to discount the notion that Mars is seismically active today but at a lower level of activity. Models are explored for present day Mars seismicity. Depending on the sensitivity and geometry of a seismic network and the attenuation and scattering properties of the interior, it appears that a reasonable number of Martian seismic events would be detected over the period of a decade. The thermoelastic cooling mechanism as estimated is surely a lower bound, and a more refined estimate would take into account specifically the regional cooling of Tharsis and lead to a higher frequency of seismic events.

  16. Evaluation of West African Monsoon Processes and Feedbacks: Second West African Monsoon Modeling and Evaluation Project Experiment (WAMME II)

    NASA Astrophysics Data System (ADS)

    Xue, Y.; Lau, W. K.; Boone, A. A.; Seidou Sanda, I.; Thiaw, W. M.; Druyan, L.; Team, W.

    2013-12-01

    Despite recent progress in understanding of the West African monsoon (WAM), there are still many unanswered questions regarding to the impact of external forcings: oceans, land, and aerosols, on WAM variability, especially their roles in the Sahel drought. The West African Monsoon Modeling and Evaluation (WAMME) is a project comprised of both general circulation models (GCMs) and regional climate models (RCMs) with the objective to collectively provide best estimation of the relative importance of all those external forcing on WAM on seasonal to multi-decadal time scales. WAMME research activities are closely coordinated with those of AMMA, involving many African institutions. Observational evidence has shown strong decadal climate variabilities in the Sahel from the 1950s to the 2000s, not only in precipitation, but also in SST, vegetation cover, land use and land cover changes (LULCC), and aerosols. In WAMME-2, multi-model intercomparison experiments are designed to test how seasonal and decadal variabilities of WAM precipitation are associated with these forcings, and assess their relative contributions in producing/amplifying the WAM seasonal and decadal climate variability. The sensitivity of the WAM variability to those external forcings is also examined. The WAMME-2 strategy is to apply observational data-based anomaly forcing of SST, land surface and aerosols, i.e., "idealized but realistic" forcing, in GCM and RCM simulations with the specific purpose of estimating the relative impacts of each forcing and feedback mechanisms. In the SST experiment, in addition to the global SST effect, each ocean's role is also evaluated. The preliminary results from most GCMs consistently indicate that SST has a maximum impact on the WAM decadal variability compared with other forcings, and that the effect of the Pacific Ocean is most dominant. The models, however, differ in producing other oceans' contribution. Moreover, the models with specified maximum SST forcing are

  17. Seismic mapping of shallow fault zones in the San Gabriel Mountains from the Los Angeles Region Seismic Experiment, southern California

    USGS Publications Warehouse

    Fuis, G.S.; Ryberg, T.; Lutter, W.J.; Ehlig, P.L.

    2001-01-01

    During the Los Angeles Region Seismic Experiment (LARSE), a reflection/refraction survey was conducted along a profile (line 1) extending from Seal Beach, California, northeastward to the Mojave Desert and crossing the Los Angeles and San Gabriel Valley basins and San Gabriel Mountains. In most shot gathers from the southern and central San Gabriel Mountains, clear secondary arrivals are seen that merge, or appear to merge, with first arrivals at three locations, including the location of the Vincent thrust fault, an exposed late Mesozoic/early Cenozoic megathrust. These secondary arrivals are interpretable as reflections in the shallow crust (<5 km depth) from a concave-upward interface that projects to the surface in the north near the Vincent thrust fault, is offset in its central part at the San Gabriel fault (an old branch of the San Andreas fault), and terminates in the south at 1 to 2 km depth at the southern mountain front. The velocity structure above and below this interface strongly suggests it is the Vincent thrust fault: intermediate velocities (6.2 km/s), consistent with mylonites overlying the Vincent thrust fault, are observed above it; lower velocities (5.8 km/s), consistent with the Pelona Schist underlying the Vincent thrust fault, are observed below it. Problems arise, however, in attempting to match this reflector to the exposed Vincent thrust fault, which is seen in outcrops east of line 1. The Vincent thrust fault is shallower than the reflector in most places. An unmapped structure (steep fault, monocline, or thrust fault) is required between line 1 and the outcrops that either drops the Vincent thrust fault down to the depths of the reflector or repeats the Vincent thrust fault beneath line 1 in the footwall of another thrust fault. An alternative interpretation of the reflector is a deep greenstone horizon within the Pelona Schist, although this alternative is not favored by the velocity structure. Copyright 2001 by the American

  18. Racism and mental health: the African American experience.

    PubMed

    Williams, D R; Williams-Morris, R

    2000-01-01

    This paper provides an overview of United States-based research on the ways in which racism can affect mental health. It describes changes in racial attitudes over time, the persistence of negative racial stereotypes and the ways in which negative beliefs were incorporated into societal policies and institutions. It then reviews the available scientific evidence that suggests that racism can adversely affect mental health status in at least three ways. First, racism in societal institutions can lead to truncated socioeconomic mobility, differential access to desirable resources, and poor living conditions that can adversely affect mental health. Second, experiences of discrimination can induce physiological and psychological reactions that can lead to adverse changes in mental health status. Third, in race-conscious societies, the acceptance of negative cultural stereotypes can lead to unfavorable self-evaluations that have deleterious effects on psychological well-being. Research directions are outlined.

  19. Free-field seismic ground motion in non-proliferation experiment

    SciTech Connect

    Garbin, H.G.

    1994-06-01

    In addition to stress and acceleration measurements made in the inelastic regime, Sandia fielded two triaxial accelerometer packages in the seismic free-field for the NON-PROLIFERATION EXPERIMENT (NPE). The gauges were located at ranges of 190 and 200 m from the center of the ANFO-laden cavity on the opposite sides of a vertical fault. This location allowed us to assess several different seismological aspects related to non-proliferation. The radial and vertical components of the two packages show similar motion. Comparisons are made with similar data from nuclear tests to estimate yield, calculate seismic energy release and to detect spectral differences between nuclear and non-nuclear explosions. The wave forms of NPE differ significantly from nuclear explosions. The first two peak amplitudes of NPE are comparable while the nuclear explosion initial peak is much larger than the second peak. The calculated seismic energies imply that the conventional explosions couple to the medium much better at low frequencies than do nuclear explosions and that nuclear explosions contain more high frequency energy than NPE. Radial and vertical accelerations were integrated for displacement and indicate there was movement across the fault.

  20. TOMO-ETNA MED-SUV.ISES an active seismic and passive seismic experiment at Mt. Etna volcano. An integrated marine and onland geophysical survey.

    NASA Astrophysics Data System (ADS)

    Ibáñez, Jesus. M.; Patane, Domenico; Puglisi, Guisseppe; Zuccarello, Lucciano; Bianco, Francesca; Luehr, Birger; Diaz-Moreno, Alejandro; Prudencio, Janire; Koulakov, Ivan; Del Pezzo, Edoardo; Cocina, Ornella; Coltelli, Mauro; Scarfi, Lucciano; De Gori, Pascuale; Carrion, Francisco

    2014-05-01

    An active seismic experiment to study the internal structure of Etna Volcano is going to carried out on Sicily and Aeolian islands. The main objective of the TOMO-ETNA MED-SUV.ISES experiment, beginning in summer 2014, is to perform a high resolution seismic tomography, in velocity and attenuation, in Southern Italy, by using active and passive seismic data, in an area encompassing outstanding volcanoes as Mt. Etna, and Aeolian volcanoes. The achievement of this objective is based on the integration and sharing of the in-situ marine and land experiments and observations and on the implementation of new instruments and monitoring systems. For the purpose, onshore and offshore seismic stations and passive and active seismic data generated both in marine and terrestrial environment will be used. Additionally, other geophysical data, mainly magnetic and gravimetric data will be considered to obtain a joint Upper Mantle-Crust structure that could permit to make progress in the understanding of the dynamic of the region. This multinational experiment which involves institutions from Spain, Italy, Germany, United Kingdom, Ireland, France, Malta, Portugal, Russia, USA and Mexico. During the experiment more than 6.600 air gun shots performed by the Spanish Oceanographic vessel "Sarmiento de Gamboa" will be recorder on a dense local seismic network consisting of 100 on land non-permanent stations, 70 on land permanent stations and 20-25 OBSs. Contemporaneously other marine geophysical measures will be performed using a marine Gravimeter LaCoste&Romberg Air-Sea Gravity System II and a Marine Magnetometer SeaSPY. The experiments will provide a unique data set in terms of data quantity and quality, and it will provide a detailed velocity and attenuation structural image of volcano edifice. The results will be essential in the development and interpretation of future volcanic models. It is noteworthy that this project is fully transversal, multidisciplinary and crosses several

  1. The influences and experiences of African American undergraduate science majors at predominately White universities

    NASA Astrophysics Data System (ADS)

    Blockus, Linda Helen

    The purpose of this study is to describe and explore some of the social and academic experiences of successful African American undergraduate science majors at predominately White universities with the expectation of conceptualizing emerging patterns for future study. The study surveyed 80 upperclass African Americans at 11 public research universities about their perceptions of the influences that affect their educational experiences and career interests in science. The mailed survey included the Persistence/ voluntary Dropout Decision Scale, the Cultural Congruity Scale and the University Environment Scale. A variety of potential influences were considered including family background, career goals, psychosocial development, academic and social connections with the university, faculty relationships, environmental fit, retention factors, validation, participation in mentored research projects and other experiences. The students' sources of influences, opportunities for connection, and cultural values were considered in the context of a research university environment and investigated for emerging themes and direction for future research. Results indicate that performance in coursework appears to be the most salient factor in African American students' experience as science majors. The mean college gpa was 3.01 for students in this study. Challenging content, time demands, study habits and concern with poor grades all serve to discourage students; however, for most of the students in this study, it has not dissuaded them from their educational and career plans. Positive course performance provided encouragement. Science faculty provide less influence than family members, and more students find faculty members discouraging than supportive. Measures of faculty relations were not associated with academic success. No evidence was provided to confirm the disadvantages of being female in a scientific discipline. Students were concerned with lack of minority role models

  2. An Intersectional Social Capital Analysis of the Influence of Historically Black Sororities on African American Women's College Experiences at a Predominantly White Institution

    ERIC Educational Resources Information Center

    Greyerbiehl, Lindsay; Mitchell, Donald, Jr.

    2014-01-01

    Research exploring the college experiences of African American women at predominantly White institutions (PWI) continues to be a necessity as African American women graduate at lower rates than their racial/ethnic peers. This qualitative study explored the influence historically Black sororities had on the college experiences of African American…

  3. Seismic risk mitigation in deep level South African mines by state of the art underground monitoring - Joint South African and Japanese study

    NASA Astrophysics Data System (ADS)

    Milev, A.; Durrheim, R.; Nakatani, M.; Yabe, Y.; Ogasawara, H.; Naoi, M.

    2012-04-01

    Two underground sites in a deep level gold mine in South Africa were instrumented by the Council for Scientific and Industrial Research (CSIR) with tilt meters and seismic monitors. One of the sites was also instrumented by JApanese-German Underground Acoustic emission Research in South Africa (JAGUARS) with a small network, approximately 40m span, of eight Acoustic Emission (AE) sensors. The rate of tilt, defined as quasi-static deformations, and the seismic ground motion, defined as dynamic deformations, were analysed in order to understand the rock mass behavior around deep level mining. In addition the high frequency AE events recorded at hypocentral distances of about 50m located at 3300m below the surface were analysed. A good correspondence between the dynamic and quasi-static deformations was found. The rate of coseismic and aseismic tilt, as well as seismicity recorded by the mine seismic network, are approximately constant until the daily blasting time, which takes place from about 19:30 until shortly before 21:00. During the blasting time and the subsequent seismic events the coseismic and aseismic tilt shows a rapid increase.Much of the quasi-static deformation, however, occurs independently of the seismic events and was described as 'slow' or aseismic events. During the monitoring period a seismic event with MW 2.2 occurred in the vicinity of the instrumented site. This event was recorded by both the CSIR integrated monitoring system and JAGUARS acoustic emotion network. The tilt changes associated with this event showed a well pronounced after-tilt. The aftershock activities were also well recorded by the acoustic emission and the mine seismic networks. More than 21,000 AE aftershocks were located in the first 150 hours after the main event. Using the distribution of the AE events the position of the fault in the source area was successfully delineated. The distribution of the AE events following the main shock was related to after tilt in order to

  4. Investigation of River Seismic Signal Induced by Sediment Transport and Water Flow: Controlled Dam Breaking Experiments

    NASA Astrophysics Data System (ADS)

    Chen, H. Y.; Chen, S. C.; Chao, W. A.

    2015-12-01

    Natural river's bedload often hard to measure, which leads numerous uncertainties for us to predict the landscape evolution. However, the measurement of bedload flux has its certain importance to estimate the river hazard. Thus, we use seismometer to receive the seismic signal induced by bedload for partially fill the gap of field measurement capabilities. Our research conducted a controlled dam breaking experiments at Landao River, Huisun Forest since it has advantage to well constraining the spatial and temporal variation of bedload transport. We set continuous bedload trap at downstream riverbed of dam to trap the transport bedload after dam breaking so as to analyze its grain size distribution and transport behavior. In the meantime we cooperate with two portable velocity seismometers (Guralp CMG6TD) along the river to explore the relationship between bedload transport and seismic signal. Bedload trap was divided into three layers, bottom, middle, and top respectively. After the experiment, we analyzed the grain size and found out the median particle size from bottom to top is 88.664mm, 129.601mm, and 214.801mm individually. The median particle size of top layer is similar with the upstream riverbed before the experiment which median particle size is 230.683mm. This phenomena indicated that as the river flow become stronger after dam breaking, the sediment size will thereupon become larger, which meant the sediment from upstream will be carried down by the water flow and turned into bedload. Furthermore, we may tell apart the seismic signal induced by water flow and bedload by means of two different position seismometers. Eventually, we may estimate the probable error band of bedload quantity via accurately control of water depth, time-lapse photography, 3D LiDAR and other hydrology parameters.

  5. Striving to be in the profession and of It: the African American experience in physical education and kinesiology.

    PubMed

    Wiggins, David K; Wiggins, Brenda P

    2011-06-01

    This study analyzes the experiences of African Americans in the physical education and kinesiology profession since the late 1850s. Using a variety of primary and secondary source material, we place special emphasis on the experiences of African American physical educators in higher education and in the American Alliance for Health, Physical Education, Recreation and Dance and its southern, regional, and state chapters. Apparent from this examination is that African Americans have experienced various forms of racially discriminatory practices in physical education and kinesiology and have found it extraordinarily difficult to assume leader ship positions in the profession and be acknowledged for their scholarly and academic accomplishments. PMID:21699112

  6. Striving to be in the profession and of It: the African American experience in physical education and kinesiology.

    PubMed

    Wiggins, David K; Wiggins, Brenda P

    2011-06-01

    This study analyzes the experiences of African Americans in the physical education and kinesiology profession since the late 1850s. Using a variety of primary and secondary source material, we place special emphasis on the experiences of African American physical educators in higher education and in the American Alliance for Health, Physical Education, Recreation and Dance and its southern, regional, and state chapters. Apparent from this examination is that African Americans have experienced various forms of racially discriminatory practices in physical education and kinesiology and have found it extraordinarily difficult to assume leader ship positions in the profession and be acknowledged for their scholarly and academic accomplishments.

  7. A Gravity data along LARSE (Los Angeles Regional Seismic Experiment) Line II, Southern California

    USGS Publications Warehouse

    Wooley, R.J.; Langenheim, V.E.

    2001-01-01

    The U.S. Geological Survey conducted a detailed gravity study along part of the Los Angeles Regional Seismic Experiment (LARSE) transect across the San Fernando Basin and Transverse Ranges to help characterize the structure underlying this area. 249 gravity measurements were collected along the transect and to augment regional coverage near the profile. An isostatic gravity low of 50-60 mGal reflects the San Fernando-East Ventura basin. Another prominent isostatic gravity with an amplitude of 30 mGal marks the Antelope Valley basin. Gravity highs occur over the Santa Monica Mountains and the Transverse Ranges. The highest isostatic gravity values coincide with outcrops of Pelona schist.

  8. African American eighth-grade female students' perceptions and experiences as learners of science literacy

    NASA Astrophysics Data System (ADS)

    Crim, Sharan R.

    The National Assessment of Educational Progress (2000) reports an achievement gap between male and female students and majority and minority students in science literacy. Rutherford and Algren (2000) describe a scientifically literate person as one who is aware that science, mathematics, and technology are interdependent human enterprises with strengths and limitations; understands key concepts and principles of science; is familiar with the natural world and recognizes both its diversity and unity; and uses scientific knowledge and scientific ways of thinking for individual and social purposes. The purpose of this qualitative case study research was to investigate African American eighth grade female students' perceptions and experiences as learners of science literacy. A social learning theory (Bandura, 1986) and constructivist theory (Vygotsky, 1977) served as a guide for the researcher. Two questions were explored: (1) What are African American eighth grade female students' perceptions and experiences as learners of science literacy? (2) In what ways do the perceptions and experiences of African American eighth grade female students influence their learning of science literacy? Purposeful sampling (Merriam, 1998) was used with four African American eighth grade female students selected as participants for the study. Data collection and analysis occurred between February and August in a single year. Data sources included an open-ended questionnaire, two in-depth interviews with each participant (Seidman, 1991); classroom observations, participant reflective journals, student artifacts, and a researcher's log. Data were analyzed through the constant comparative method (Glaser & Strauss, 1967), and richly descriptive participant portraits and qualitative case studies (Merriam, 1998) were used to report the findings. Three themes emerged from the study that positively affected the perceptions and experiences of African American eighth grade female students as

  9. Preliminary Results from the iMUSH Active Source Seismic Experiment

    NASA Astrophysics Data System (ADS)

    Levander, Alan; Kiser, Eric; Palomeras, Imma; Zelt, Colin; Schmandt, Brandon; Hansen, Steve; Harder, Steven; Creagar, Kenneth; Vidale, John; Abers, Geoffrey

    2015-04-01

    iMUSH (imaging Magma Under Saint Helens) is a US NSF sponsored multi-disciplinary investigation of Mount Saint Helens (MSH), currently the most active volcano in the Cascades arc in the northwestern United States. The project consists of active and passive seismic experiments, extensive magnetotelluric sounding, and geological/geochemical studies involving scientists at 7 institutions in the U.S. and Europe. The long-term goal of the seismic project is to combine analysis of the active source data with that of data from the 70 element broadband seismograph operating from summer 2014 until 2016. Combining seismic and MT analyses with other data, we hope to image the MSH volcanic plumbing system from the surface to the subducting Juan de Fuca slab. Here we describe preliminary results of the iMUSH active source seismic experiment, conducted in July and August 2014. The active source experiment consisted of twenty-three 454 or 908 kg weight shots recorded by ~3500 seismographs deployed at ~6,000 locations. Of these instruments, ~900 Nodal Seismic instruments were deployed continuously for two weeks in an areal array within 10 km of the MSH summit. 2,500 PASSCAL Texan instruments were deployed twice for five days in 3 areal arrays and 2 dense orthogonal linear arrays that extended from MSH to distances > 80 km. Overall the data quality from the shots is excellent. The seismograph arrays also recorded dozens of micro-earthquakes beneath the MSH summit and along the MSH seismic zone, and numerous other local and regional earthquakes. In addition, at least one low frequency event beneath MSH was recorded during the experiment. At this point we have begun various types of analysis of the data set: We have determined an average 1D Vp structure from stacking short-term/long-term average ratios, we have determined the 2-D Vp structure from ray-trace inversions along the two orthogonal profiles (in the NW-SE and NE-SW directions), and we have made low-fold CMP stacks of the

  10. From their own voices: the lived experience of African American registered nurses.

    PubMed

    Wilson, Deborah W

    2007-04-01

    This phenomenological study described the lived experience of African American registered nurses providing nursing care to individuals, families, and communities in southeast Louisiana. Data were collected from 13 African American registered nurses using semistructured interviews and a focus group. Analysis of the phenomenological data revealed two essential themes, (a) connecting with the patient and (b) proving yourself; and four incidental themes, (a) a fulfilling dream, (b) being invisible and voiceless, (c) surviving and persevering, and (d) mentoring and role modeling. The findings revealed that the general perception among participants was that they were not fully accepted as equal professionals by their Caucasian nurse colleagues, other health care providers, and sometimes patients. The findings of the study indicate the immediate need to address and resolve the issues of diversity within the nursing profession. Nursing will also have to reform its system and practices to embrace and support diversity. PMID:17416716

  11. Field Report on the iMUSH Active Source Seismic Experiment

    NASA Astrophysics Data System (ADS)

    Kiser, E.; Levander, A.; Schmandt, B.; Palomeras, I.; Harder, S. H.; Creager, K. C.; Vidale, J. E.; Malone, S. D.

    2014-12-01

    In the second half of July we completed the iMUSH active source seismic experiment, one component of the Imaging Magma Under Saint Helens project. A team of ~75 volunteers deployed 3500 seismographs to ~5920 locations on and around Mount St. Helens over the course of 3 weeks. This instrument deployment was accompanied by 23 shots distributed around the volcano. Instrumentation consisted of ~2550 Reftek 125A (Texan) seismographs with 4.5 Hz geophones, and 920 Nodal Seismic recorders with 10 Hz geophones. The shots were also recorded by the permanent stations of the Pacific Northwest Seismograph Network and 70 iMUSH broadband seismographs. Fifteen of the shots, 424 kg each, formed two rings around Mount Saint Helens at 15 km and 30 km radius from the summit. Eight of the shots, 828 kg each, were fired at distances of 50 to 80 km from MSH on NW-SE and NE-SW azimuths. The deployment geometry consisted of two lines oriented NW/SE and NE/SW, and three arrays. The offset of the lines ranged from 150 km to 190 km with an average spacing of 200 m. The first array was centered on the volcano with a radius of 30 km, and required both driving and hiking to deploy. Arrays two and three were set out with, and centered on, the NW/SE line. These arrays had a distance range from MSH of 30-75 km and an azimuth range of about 100 degrees. In addition to this large-scale deployment, we set out 7 beamforming arrays approximately collocated with iMUSH broadband seismographs, and above clusters of seismicity in the region. The aperture of these arrays was about 1 km with an instrument spacing of 100 m. The final deployment ended only days before the AGU abstract deadline, so we have not yet examined all of the data. However, the preliminary indications are that signal to noise is excellent: The shots, several of which registered on PNSN as ML>2.1, carried across the entire array, and were recorded as far away as Seattle and Corvallis on permanent stations. The array also recorded a

  12. The perceived racism scale: a multidimensional assessment of the experience of white racism among African Americans.

    PubMed

    McNeilly, M D; Anderson, N B; Armstead, C A; Clark, R; Corbett, M; Robinson, E L; Pieper, C F; Lepisto, E M

    1996-01-01

    The experience of racism is a complex, multidimensional phenomenon. At present, there are few instruments that attempt to capture the experience of racism in all of its complexity. For this study, a new instrument, the Perceived Racism Scale, has been constructed to assess the experience of racism in African Americans in a multidimensional manner. The scale not only provides a measure of the frequency of exposure to many manifestations of racism (including individual and institutional, overt and covert, attitudinal, behavioral, and cultural), but takes a step forward in more comprehensively measuring the experience of racism by assessing emotional and behavioral coping responses to racism. These responses are measured with respect to exposure to racism in three situational domains: on the job, in academic settings, and in the public realm. Measurement of responses to a fourth domain, that of exposure to racist statements, is also included. It is hoped that the Perceived Racism Scale will facilitate a more comprehensive understanding of the experience of racism among African Americans and, through its use in research and clinical settings, will ultimately move us closer to reducing the prevalence and potentially untoward effects of racism.

  13. Crustal structure variations along the NW-African continental margin: A comparison of new and existing models from wide-angle and reflection seismic data

    NASA Astrophysics Data System (ADS)

    Klingelhoefer, Frauke; Biari, Youssef; Sahabi, Mohamed; Aslanian, Daniel; Schnabel, Michael; Matias, Luis; Benabdellouahed, Massinissa; Funck, Thomas; Gutscher, Marc-André; Reichert, Christian; Austin, James A.

    2016-04-01

    Deep seismic data represent a key to understand the geometry and mechanism of continental rifting. The passive continental margin of NW-Africa is one of the oldest on earth, formed during the Upper Triassic-Lower Liassic rifting of the central Atlantic Ocean over 200 Ma. We present new and existing wide-angle and reflection seismic data from four study regions along the margin located in the south offshore DAKHLA, on the central continental margin offshore Safi, in the northern Moroccan salt basin, and in the Gulf of Cadiz. The thickness of unthinned continental crust decreases from 36 km in the North to about 27 km in the South. Crustal thinning takes place over a region of 150 km in the north and only 70 km in the south. The North Moroccan Basin is underlain by highly thinned continental crust of only 6-8 km thickness. The ocean-continent transition zone shows a variable width between 40 and 70 km and is characterized by seismic velocities in between those of typical oceanic and thinned continental crust. The neighbouring oceanic crust is characterized by a thickness of 7-8 km along the complete margin. Relatively high velocities of up to 7.5 km/s have been imaged between magnetic anomalies S1 and M25, and are probably related to changes in the spreading velocities at the time of the Kimmeridgian/Tithonian plate reorganization. Volcanic activity seems to be mostly confined to the region next to the Canary Islands, and is thus not related to the initial opening of the ocean, which was associated to only weak volcanism. Comparison with the conjugate margin off Nova Scotia shows comparable continental crustal structures, but 2-3 km thinner oceanic crust on the American side than on the African margin.

  14. What makes African American health disparities newsworthy? An experiment among journalists about story framing.

    PubMed

    Hinnant, Amanda; Oh, Hyun Jee; Caburnay, Charlene A; Kreuter, Matthew W

    2011-12-01

    News stories reporting race-specific health information commonly emphasize disparities between racial groups. But recent research suggests this focus on disparities has unintended effects on African American audiences, generating negative emotions and less interest in preventive behaviors (Nicholson RA, Kreuter MW, Lapka C et al. Unintended effects of emphasizing disparities in cancer communication to African-Americans. Cancer Epidemiol Biomarkers Prev 2008; 17: 2946-52). They found that black adults are more interested in cancer screening after reading about the progress African Americans have made in fighting cancer than after reading stories emphasizing disparities between blacks and whites. This study builds on past findings by (i) examining how health journalists judge the newsworthiness of stories that report race-specific health information by emphasizing disparities versus progress and (ii) determining whether these judgments can be changed by informing journalists of audience reactions to disparity versus progress framing. In a double-blind-randomized experiment, 175 health journalists read either a disparity- or progress-framed story on colon cancer, preceded by either an inoculation about audience effects of such framing or an unrelated (i.e. control) information stimuli. Journalists rated the disparity-frame story more favorably than the progress-frame story in every category of news values. However, the inoculation significantly increased positive reactions to the progress-frame story. Informing journalists of audience reactions to race-specific health information could influence how health news stories are framed.

  15. Multichannel seismic-reflection profiling on the R/V Maurice Ewing during the Los Angeles Region Seismic Experiment (LARSE), California

    USGS Publications Warehouse

    Brocher, Thomas M.; Clayton, Robert W.; Klitgord, Kim D.; Bohannon, Robert G.; Sliter, Ray; McRaney, John K.; Gardner, James V.; Keene, J.B.

    1995-01-01

    This report describes the acquisition of deep-crustal multichannel seismic-reflection data in the Inner California Borderland aboard the R/V Maurice Ewing, conducted in October 1994 as part of the Los Angeles Regional Seismic Experiment (LARSE). LARSE is a cooperative study of the crustal structure of southern California involving earth scientists from the U.S. Geological Survey, Caltech, the University of Southern California, the University of California Los Angeles, and the Southern California Earthquake Center (SCEC). During LARSE, the R/V Ewing's 20- element air gun array, totaling 137.7 liters (8470 cu. in.), was used as the primary seismic source for wide-angle recording along three main onshore-offshore lines centered on the Los Angeles basin and the epicenters of the 1933 Long Beach and 1994 Northridge earthquakes. The LARSE onshore-offshore lines were each 200-250 km long, with the offshore portions being between 90 and 150 km long. The nearly 24,000 air gun signals generated by the Ewing were recorded by an array of 170 PASSCAL REFTEK recorders deployed at 2 km intervals along all three of the onshore lines and 9 ocean bottom seismometers (OBSs) deployed along two of the lines. Separate passes over the OBS-deployment lines were performed with a long air gun repetition rate (60 and 90 seconds) to minimize acoustic-wave interference from previous shots in the OBS data. The Ewing's 4.2-km, 160-channel, digital streamer was also used to record approximately 1250 km of 40-fold multichannel seismic-reflection data. To enhance the fold of the wide-angle data recorded onshore, mitigating against cultural and wind noise in the Los Angeles basin, the entire ship track was repeated at least once resulting in fewer than about 660 km of unique trackline coverage in the Inner Borderland. Portions of the seismic-reflection lines were repeated up to 6 times. A variety of other geophysical data were also continuously recorded, including 3.5 kHz bathymetry, multi

  16. ENAM: A community seismic experiment targeting rifting processes and post-rift evolution of the Mid Atlantic US margin

    NASA Astrophysics Data System (ADS)

    Van Avendonk, H. J.; Magnani, M. B.; Shillington, D. J.; Gaherty, J. B.; Hornbach, M. J.; Dugan, B.; Long, M. D.; Lizarralde, D.; Becel, A.; Benoit, M. H.; Harder, S. H.; Wagner, L. S.; Christeson, G. L.

    2014-12-01

    The continental margins of the eastern United States formed in the Early Jurassic after the breakup of supercontinent Pangea. The relationship between the timing of this rift episode and the occurrence of offshore magmatism, which is expressed in the East Coast Magnetic Anomaly, is still unknown. The possible influence of magmatism and existing lithospheric structure on the rifting processes along margin of the eastern U.S. was one of the motivations to conduct a large-scale community seismic experiment in the Eastern North America (ENAM) GeoPRISMS focus site. In addition, there is also a clear need for better high-resolution seismic data with shallow penetration on this margin to better understand the geological setting of submarine landslides. The ENAM community seismic experiment is a project in which a team of scientists will gather both active-source and earthquake seismic data in the vicinity of Cape Hatteras on a 500 km wide section of the margin offshore North Carolina and Virginia. The timing of data acquisition in 2014 and 2015 facilitates leveraging of other geophysical data acquisition programs such as Earthscope's Transportable Array and the USGS marine seismic investigation of the continental shelf. In April of 2014, 30 broadband ocean-bottom seismometers were deployed on the shelf, slope and abyssal plain of the study site. These instruments will record earthquakes for one year, which will help future seismic imaging of the deeper lithosphere beneath the margin. In September and October of 2014, regional marine seismic reflection and refraction data will be gathered with the seismic vessel R/V Marcus Langseth, and airgun shots will also be recorded on land to provide data coverage across the shoreline. Last, in the summer of 2015, a land explosion seismic refraction study will provide constraints on the crustal structure in the adjacent coastal plain of North Carolina and Virginia. All seismic data will be distributed to the community through IRIS

  17. Reflections on E. E. Just, Black Apollo of Science, and the experiences of African American scientists.

    PubMed

    Manning, Kenneth R

    2009-10-01

    The text below is a transcript of the keynote address Kenneth Manning gave at the symposium honoring E. E. Just that was held on the campus of Howard University on November 21, 2008. In his talk, Manning reflects on his experiences researching and writing Black Apollo of Science: The Life of Ernest Everett Just, his prize-winning biography published in 1983. In the process, he retells the fascinating story of the life of E. E. Just. Manning also discusses a number of other topics, including Just's legacy, the role of African Americans in science, and the importance of having minority representation on college campuses. PMID:19610070

  18. On the scalability of seismic waveform inversion: From ultrasonic experiments to global-scale tomography

    NASA Astrophysics Data System (ADS)

    Kamei, R.; Pratt, R. G.

    2012-12-01

    Seismic waveform inversion endeavors to extract high-resolution subsurface models from full seismic records by using numerical solutions of the full forward wave equation. In the last two decades, waveform inversion has been successfully applied to both active and passive seismic experiments, and has demonstrated superb resolution power over a wide-range of applications. Waveform inversion is still computationally challenging, and is well known to be a strongly non-linear and ill-conditioned inverse problem. Passive and active waveform inversions have largely been developed independently, although both originate from the work of Lailly (1983) and Tarantola (1984). In this presentation, we review a suite of past results from both active and passive source waveform inversions, and attempt to illustrate similarities and shared challenges between them. In active seismics, waveform inversion has been applied to i) ultrasonic breast cancer data to image targets of a few tens of centimeters on a side, ii) cross-well exploration data using frequencies between hundreds and a few thousands of Hz to image targets of the order of hundreds of meters on a side, iii) surface seismic for near-surface engineering problems using frequencies of tens to a few hundreds of Hz to image targets of the order of hundreds of meters to several kilometers, and iv) hydrocarbon exploration and crustal imaging using frequencies of a few, to a few tens of Hz for targets tens of kilometers on a side. In contrast, waveform inversion from passive source data uses much lower frequencies (less than 1 Hz), and images much larger target areas to retrieve iv) crustal scale structures of the order of hundreds of kilometers using data periods of one to several tens of seconds, v) upper-mantle structure on regional scales thousands of kilometers on a side using data periods of ten to a few hundred seconds, and vi) the whole-earth inversions (of order 10,000 km on a side), using a similar frequency range. Our

  19. A comparative study of seismicity statistics in laboratory stick-slip experiments and nature: Implications for fault mechanics

    NASA Astrophysics Data System (ADS)

    Goebel, Thomas; Kwiatek, Grzegorz; Becker, Thorsten; Sammis, Charles; Dresen, Georg

    2016-04-01

    Fault properties can rarely be monitored under in-situ conditions at seismogenic depth. At these depths seismicity records are possibly the only high-resolution data that can provide insight into state of stress and mechanics of faulting. We analyze series of laboratory experiments on faults that developed during stick-slip on saw-cut and fractured surfaces under upper crustal stress conditions. Stick-slip experiments were performed on surfaces with varying roughness and fracture surfaces that evolved into fault zones with pronounced damage zones. We monitor and analyze acoustic emission events that exhibit many striking similarities to natural seismicity across all examined scales. These similarities include pronounced Gutenberg-Richter-type magnitude distributions, Omori-type aftershock decay, and off-fault seismicity distributions that decay as a power law with distance. In the laboratory, fault roughness and heterogeneity are critical in concentrating stresses that lead to local AE clustering, and differences in off-fault activities and lower b-values. Similar observations of earthquake clustering and b-value variations were made for natural faults such as the Parkfield segment of the San Andreas fault. In addition to seismicity statistics, we conducted a detailed analysis of moment tensors, focusing on relative contributions from isotropic and deviatoric components to laboratory seismicity. In contrast to natural seismicity, our results revealed a larger contribution from isotropic components. These contributions are a result of ongoing fracture processes within the evolving fault which are most pronounced after stick-slip events. Our study shows, that seismicity analyses in laboratory experiments can significantly advance our understanding of fault mechanics from the scale of single asperities to large fault zones.

  20. The experience of African American women living with HIV: creating a prevention film for teens.

    PubMed

    Norris, Anne E; DeMarco, Rosanna

    2005-01-01

    The personal and social costs of HIV are well documented. What remains unknown is the effect of public disclosure of HIV status on the individual who is doing the disclosing. This study describes the experience of four African American women living with HIV who participated in the development of an intergenerational education intervention for African American adolescent girls. These women suggested that they be filmed discussing the "dark side" of HIV in an effort to create an intergenerational education intervention that would alter the risk-taking behavior that they observed in young women in their community. After a rough cut of the film was completed, these women viewed the film and participated in a focus group during which they discussed what it was like to reveal and revisit their own painful experiences associated with becoming infected and then living with HIV. Findings from content analysis of transcribed dialogue included the following positive themes: (a) self-acceptance by telling one's own story and hearing the stories of the other women, (b) a sense of liberation by disclosing publicly one's image and message and letting go of others' judgments, (c) feeling supported by meeting other women who share the same experience, (d) value of using the film to impact or save young people from the pain one has experienced. A negative theme emerged related to personal pain in reliving the individual's history with HIV.

  1. Disability and Health: Exploring the Disablement Experience of Young Adult African Americans

    PubMed Central

    Harrison, Tracie

    2013-01-01

    Purpose The objective of this study was to examine disablement as experienced by young adult African American men and women with permanent mobility impairment. Methods This study included a sample of 5 male and 5 female participants ranging in age from 22 to 39. An exploratory descriptive design and qualitative methods, including interviews and fieldnotes, were used. Interview data was analyzed using the process of inductive qualitative content analysis. Results Basic desires for independence, shared intimacy, and psychological and physical health were not diminished by physical limitations. The disablement experience of this group is reflected in the themes of “Cumulative Losses” and “Sustained Desires.” The findings of this study describe the high level of motivation that young adult African American men and women with disabilities have to improve levels of health and well-being within the context of their impairments. Conclusion This study provides a better understanding of the contextual factors and experiences that may contribute to the development of further disability and subsequent health-related problems over time. Increased knowledge of the disablement experience of these young men and women may assist health care entities and social service providers in improving health care and rehabilitation efforts targeting this group. PMID:23745770

  2. A passive seismic experiment and ground penetration radar to characterize subsurface cavities in Eastern Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Asmaidi Chan, Septriandi; Ismail Kaka, SanLinn

    2014-05-01

    We have carried out a small-scale passive seismic experiment over a known shallow cavity at King Fahd University of Petroleum & Minerals in an attempt to characterize the near surface cavities. This experiment was conducted as part of a larger study to develop an integrated geophysical approach (i.e. seismic, gravity, resistivity and ground penetration radar) in detecting and characterizing shallow subsurface cavities. Characterizing shallow cavities is of particular interest in the eastern province of Saudi Arabia where many cavities were discovered during a number of construction projects. We used a Geospace passive seismic recording system to collect continuous data over a partly dolomitized limestone bed with several fractures and cavities. Systematically selected time series data at different times of the day were processed using Geopsy software developed by the SESAME (Site Effects Assessment using Ambient Excitations) project. Data from the 10 Hz geophone was used in this experiment and we extracted part of the data recorded during the night as this has been found to exclude most of the anthropologic noise that usually masks signals on data recorded during the day time. We analyzed time series data and performed spectral analysis. Horizontal-to-vertical ratio (H/V) and power spectral density (PSD) were performed as an enhancement tool to determine the resonance frequencies possibly associated with the shallow cavity. Various processing windows with 5% cosine tapers were applied to reduce spectral leakage. To retain the analysis at frequency range of interest between 0.1 to 20 Hz, a band-pass-filter with smoothing procedure described by Kamo and Omachi (1998) was applied. Moreover, the same frequency peaks were picked at each measuring point to check the stability of the H/V curve. The preliminary results (frequency peaks in the spectral H/V ambient ground motions as well as PSD plots) do not uniquely define the near surface cavity. However, further

  3. Seismic anisotropy of the lithosphere/asthenosphere system beneath the Rwenzori region of the East-African Rift

    NASA Astrophysics Data System (ADS)

    Homuth, Benjamin; Löbl, Ulrike; Batte, Arthur; Link, Klemens; Kasereka, Celestine; Rümpker, Georg

    2014-05-01

    We present results from a temporary seismic network of 32 broad-band stations located around the Rwenzori region of the Albertine rift at the border between Uganda and DR Congo. The study aims to constrain seismic anisotropy and mantle deformation processes in relation to the formation of the rift zone. Shear-wave splitting measurements from local and teleseismic earthquakes are used to investigate the seismic anisotropy in the crust and upper mantle beneath the Rwenzori region. At most stations, shear-wave splitting parameters obtained from individual earthquakes exhibit only minor variations with backazimuth. We therefore employ a joint inversion of SKS waveforms to derive hypothetical one-layer parameters. The corresponding fast polarizations are generally rift-parallel and the average delay time is about 1 s. On the other hand, shear phases from local events within the crust are characterized by a bimodal pattern of fast polarizations and an average delay time of 0.04 s. This observation suggests that the dominant source region for seismic anisotropy beneath the rift is located within the mantle. We use finite-frequency waveform modeling to test different models of anisotropy within the lithosphere/asthenosphere system of the rift. The results show that the rift-parallel fast polarizations are consistent with HTI anisotropy caused by rift-parallel magmatic intrusions or lenses located within the lithospheric mantle - as it would be expected during the early stages of continental rifting. Furthermore, the short-scale spatial variations in the fast polarizations observed in the southern part of the study area can be explained by effects due to sedimentary basins of low isotropic velocity in combination with a shift in the orientation of anisotropic fabrics in the upper mantle. A uniform anisotropic layer in relation to large-scale asthenospheric mantle flow is less consistent with the observed splitting parameters.

  4. Seismic Anisotropy of the Lithosphere/Asthenosphere System Beneath the Rwenzori Region of the East-African Rift

    NASA Astrophysics Data System (ADS)

    Homuth, B.; Löbl, U.; Batte, A.; Link, K.; Kasereka, C.; Rumpker, G.

    2014-12-01

    We present results from a temporary seismic network of 32 broad-band stations located around the Rwenzori region of the Albertine rift at the border between Uganda and DR Congo. The study aims to constrain seismic anisotropy and mantle deformation processes in relation to the formation of the rift zone. Shear-wave splitting measurements from local and teleseismic earthquakes are used to investigate the seismic anisotropy in the crust and upper mantle beneath the Rwenzori region. At most stations, shear-wave splitting parameters obtained from individual earthquakes exhibit only minor variations with backazimuth. We therefore employ a joint inversion of SKS waveforms to derive hypothetical one-layer parameters. The corresponding fast polarizations are generally rift-parallel and the average delay time is about 1 s. On the other hand, shear phases from local events within the crust are characterized by an average delay time of 0.04 s. This observation suggests that the dominant source region for seismic anisotropy beneath the rift is located within the mantle. We use finite-frequency waveform modeling to test different models of anisotropy within the lithosphere/asthenosphere system of the rift. The results show that the rift-parallel fast polarizations are consistent with HTI anisotropy caused by magmatic intrusions or lenses located within the lithospheric mantle - as it would be expected during the early stages of continental rifting. Furthermore, the short-scale spatial variations in the fast polarizations observed in the southern part of the study area can be explained by effects due to sedimentary basins of low isotropic velocity in combination with a shift in the orientation of anisotropic fabrics in the upper mantle. A uniform anisotropic layer in relation to large-scale asthenospheric mantle flow is less consistent with the observed splitting parameters.

  5. The application of ultrasonic seismic model experiment in quality test of cement mortar injection of Yongjiang river submarine tunnel tube foundation

    NASA Astrophysics Data System (ADS)

    Yang, Gang-Yu; Guo, Tie-Shuan; Li, Jin-Long; Yang, Dao-Sheng

    1996-11-01

    Ultrasonic seismic model experiment plays an important role in engineering multi-wave seismic prospecting (EM-SP), which has been used to do the complex engineering seismic exploration. It is introduced that the application of the technology in quality test of Yongjiang river submarine tunnel tube foundation in the paper. The material of the model was got from on-the-spot. The successful test has been made with results of the model experiment.

  6. A study of the lived experiences of African American women STEM doctoral degree completers

    NASA Astrophysics Data System (ADS)

    Squires, Stephanie Michelle

    This study examined the lived experiences of African American women (AAW) who completed doctoral degrees in a STEM (science, technology, engineering, and mathematics) discipline in the United States. This study sought to fill the gap in the literature by examining how AAW described and made meaning of lived STEM educational experiences during doctoral degree completion in the context of the intersection of being African American and a woman. This study utilized a theoretical perspective based upon three theories: (a) critical race theory as a framework to gather AAW's narratives about STEM doctorate education, (b) Black feminist thought as a framework to view the intersection of being African American and a woman in the United States, and (c) the science identity model as a framework to view how women of color successfully complete scientific graduate degrees. Participants revealed that being an African American and a woman in a STEM doctoral program often complicated an already difficult process of completing the doctoral degree. The participants described the educational experience as challenging, particularly the writing of the dissertation. The challenges that the participants faced were due to various factors such as difficult advisor/advisee relationships, tedious writing and revision processes, politics, and lack of information regarding the doctoral degree process. The findings suggested that AAW participants confronted intrinsic bias while completing STEM doctoral degrees, which led to isolation and feelings of being an impostor---or feelings of not belonging in scientific studies. The findings also indicated that the women in this study ascribed success in dissertation writing and degree completion to one or more of the following attributes: (a) having a clear plan, (b) taking ownership of the writing process, (c) having an engaged advisor, (d) learning the writing style of the advisor, (e) understanding the temperament of the advisor, (f) personal will

  7. DHOFAR Seismic Experiment: First results to understand the breakup processes in a passive margin context

    NASA Astrophysics Data System (ADS)

    Tiberi, C.; Leroy, S.; D'Acremont, E.; Pointu, A.; Ebinger, C.; Brisbourne, A.; Denton, P.; Al-Lazki, A.; Al-Azri, H.; Bin Monshir Bahlaf, S.; Brunet, C.; Famin, V.; Labrousse, L.

    2004-12-01

    The process of strain localisation preceding the onset of seafloor spreading is still poorly understood, though extensively studied. The reason is the differences in lithospheric properties, proximity to hot spot(s) and melt generation and extraction that lead to a variety of structural styles with major differences. The eastern Gulf of Aden represents a natural laboratory to study passive continental margins for many reasons: post-rift sedimentary strata are relatively thin, both onshore and nearshore structures are well-exposed, and conjugate margins can be precisely reconstructed. A first cruise (ENCENS-SHEBA), in 2000, has established the structural and geophysical framework using bathymetric swath mapping and underway geophysics. Later on, the Dhofar seismic experiment consisted in the deployment of a network of 11 broadband seismic stations from March 2003 to March 2004 on the northern margin, in the Dhofar area, southern Oman. This experiment was dedicated to the detailed study of the crust and upper mantle beneath the northern passive margin. CMG40TD 3-components seismometers from SEIS-UK network were used. We have recorded hundreds of teleseismic events with a good azimuthal coverage. Three main studies are then attempted. First, a teleseismic image of the first 200 km depth will be established using the P- and PKP-phases. This will allow a 3D representation of crustal and upper mantle velocity structures. We present here the preliminary results from the study of the traveltime residuals. The image resolution shall be enhanced by combining gravity data. Second, a receiver function analysis will locally determine the depth of the main interfaces (eg, Moho boundary). Finally, events recorded within the 1000-6000 km distance range will improve the regional S-wave velocity structure in this area and will help to locate the main regional wide structures related to this extended area.

  8. Experiences of racist events are associated with negative health consequences for African American women.

    PubMed

    Kwate, Naa Oyo A; Valdimarsdottir, Heiddis B; Guevarra, Josephine S; Bovbjerg, Dana H

    2003-06-01

    This study investigated whether experiences of racist events were related to psychological distress, negative health behaviors, and health problems. Participants were 71 African American women (mean age 44.4) who were recruited from an urban cancer-screening clinic as part of a larger longitudinal study on familial risk of breast cancer. Participants completed three study assessments, approximately one month apart, and data were collected via self-report. Correlational analyses revealed that past year and lifetime racism were both related to psychological distress. Among smokers and drinkers, past year racism was positively correlated with number of cigarettes and drinks consumed. Lifetime racism was negatively related to perceived health, and positively related to lifetime history of physical disease and frequency of recent common colds. Analyses using a general linear model revealed that these relationships were largely unaccounted for by other variables. In addition, demographic variables such as income and education were not related to experiences of racism. The results suggest that racism can be detrimental to African American's well being and should be investigated in health disparities research.

  9. African American women's preventative care usage: the role of social support and racial experiences and attitudes.

    PubMed

    Pullen, Erin; Perry, Brea; Oser, Carrie

    2014-09-01

    Research suggests that African Americans are less likely to utilise preventative care services than Americans of European descent, and that these patterns may contribute to racial health disparities in the United States. Despite the persistence of inequalities in preventative care utilisation, culturally relevant factors influencing the use of these gateway health services have been understudied among marginalised groups. Using a stratified sample of 205 low-income African American women, this research examines the predictors of receiving a physical exam, with a particular emphasis on how differing levels of social support from friend and family networks and experiences of racial discrimination and cultural mistrust shape utilisation. The findings underscore the importance of traditional predictors of utilisation, including insurance status and having a usual physician. However, they also indicate that supportive ties to friendship networks are associated with higher predicted rates of having an annual physical exam, while social support from family and sentiments of cultural mistrust are associated with lower rates of utilisation. Broadly, the findings indicate that even as traditional predictors of help-seeking become less relevant, it will be critical to explore how variations in discrimination experiences and social relationships across marginalised groups drive patterns of preventative care utilisation.

  10. Racism at the intersections: Gender and socioeconomic differences in the experience of racism among African Americans.

    PubMed

    Kwate, Naa Oyo A; Goodman, Melody S

    2015-09-01

    Several studies investigating the health effects of racism have reported gender and socioeconomic differences in exposures to racism, with women typically reporting lower frequencies, and individuals with greater resources reporting higher frequencies. This study used diverse measures of socioeconomic position and multiple measures and methods to assess experienced racism. Socioeconomic position included education and financial and employment status. Quantitative racism measures assessed individual experiences with day-to-day and with major lifetime incidents and perceptions of the extent to which African Americans as a group experience racism. A brief qualitative question asked respondents to describe a racist incident that stood out in recent memory. Participants comprised a probability sample of N = 144 African American adults aged 19 to 87 residing in New York City. Results suggested that women reported fewer lifetime incidents but did not differ from men on everyday racism. These differences appear to be partly because of scale content. Socioeconomic position as measured by years of education was positively associated with reported racism in the total sample but differently patterned across gender; subjective social status showed a negative association. Qualitative responses describing memorable incidents fell into 5 key categories: resources/opportunity structures, criminal profiling, racial aggression/assault, interpersonal incivilities, and stereotyping. In these narratives, men were more likely to offer accounts involving criminal profiling, and women encountered incivilities more often. The findings highlight the need for closer attention to the intersection of gender and socioeconomic factors in investigations of the health effects of racism. PMID:26460700

  11. South Africans' experiences of being old and of care and caring in a transitional period.

    PubMed

    Bohman, Doris M; van Wyk, Neltjie C; Ekman, Sirkka-Liisa

    2011-09-01

    This focused ethnographic study aimed to illuminate a group of South Africans' experiences of being old and of care and caring in a transitional period. With a growing number of older people in Africa, studies on the individual experiences may help to develop care which is more sensitively based on the needs for older people in a changing Southern Africa context. Data were collected through group and individual in-depth interviews and participant observations which involved 16 individuals, aged 52-76. Data were analysed using a qualitative content analysis. The study showed two interrelated themes reflections on life and ubuntu - an orientation towards others. Findings were discussed from the viewpoint of the theory of gerotranscendence, showing similarities as well as differences, possibly due to societal and cultural differences. Shortage of formal care for older people living in poor conditions in Southern Africa, gave rise to the discussion for the need of a contextualized development of gerontological care. To enhance knowledge on the theory of gerotranscendence and develop guidelines for nursing in home-based care/community-based care in a South African context may be a first step to support older people in their process towards gerotranscendence.

  12. Racism at the intersections: Gender and socioeconomic differences in the experience of racism among African Americans.

    PubMed

    Kwate, Naa Oyo A; Goodman, Melody S

    2015-09-01

    Several studies investigating the health effects of racism have reported gender and socioeconomic differences in exposures to racism, with women typically reporting lower frequencies, and individuals with greater resources reporting higher frequencies. This study used diverse measures of socioeconomic position and multiple measures and methods to assess experienced racism. Socioeconomic position included education and financial and employment status. Quantitative racism measures assessed individual experiences with day-to-day and with major lifetime incidents and perceptions of the extent to which African Americans as a group experience racism. A brief qualitative question asked respondents to describe a racist incident that stood out in recent memory. Participants comprised a probability sample of N = 144 African American adults aged 19 to 87 residing in New York City. Results suggested that women reported fewer lifetime incidents but did not differ from men on everyday racism. These differences appear to be partly because of scale content. Socioeconomic position as measured by years of education was positively associated with reported racism in the total sample but differently patterned across gender; subjective social status showed a negative association. Qualitative responses describing memorable incidents fell into 5 key categories: resources/opportunity structures, criminal profiling, racial aggression/assault, interpersonal incivilities, and stereotyping. In these narratives, men were more likely to offer accounts involving criminal profiling, and women encountered incivilities more often. The findings highlight the need for closer attention to the intersection of gender and socioeconomic factors in investigations of the health effects of racism.

  13. Experiences of racist events are associated with negative health consequences for African American women.

    PubMed Central

    Kwate, Naa Oyo A.; Valdimarsdottir, Heiddis B.; Guevarra, Josephine S.; Bovbjerg, Dana H.

    2003-01-01

    This study investigated whether experiences of racist events were related to psychological distress, negative health behaviors, and health problems. Participants were 71 African American women (mean age 44.4) who were recruited from an urban cancer-screening clinic as part of a larger longitudinal study on familial risk of breast cancer. Participants completed three study assessments, approximately one month apart, and data were collected via self-report. Correlational analyses revealed that past year and lifetime racism were both related to psychological distress. Among smokers and drinkers, past year racism was positively correlated with number of cigarettes and drinks consumed. Lifetime racism was negatively related to perceived health, and positively related to lifetime history of physical disease and frequency of recent common colds. Analyses using a general linear model revealed that these relationships were largely unaccounted for by other variables. In addition, demographic variables such as income and education were not related to experiences of racism. The results suggest that racism can be detrimental to African American's well being and should be investigated in health disparities research. PMID:12856911

  14. Early-stage rifting in the southwest East African Rift: Insights from new reflection seismic data from Lakes Tanganyika and Malawi (Nyasa)

    NASA Astrophysics Data System (ADS)

    Scholz, C. A.; Wood, D. A.; Shillington, D. J.; McCartney, T.; Accardo, N. J.

    2015-12-01

    The western branch of the East African Rift is characterized by modest amounts of mainly amagmatic extension; deeply-subsided, fault-controlled basins; and large-magnitude, deep seismicity. Lakes Tanganyika and Malawi are two of the world's largest lakes, with maximum water depths of 1450 and 700 m respectively. Newly acquired seismic reflection data, along with newly reprocessed legacy data reveal thick sedimentary sections, in excess of 5 km in some localities. The 1980's vintage legacy data from Project PROBE have been reprocessed through pre-stack depth migration in Lake Tanganyika, and similar reprocessing of legacy data from Lake Malawi is forthcoming. New high-fold and large-source commercial and academic data have recently been collected in southern Lake Tanganyika, and in the northern and central basins of Lake Malawi as part of the 2015 SEGMeNT project. In the case of Lake Tanganyika, new data indicate the presence of older sediment packages that underlie previously identified "pre-rift" basement (the "Nyanja Event"). These episodes of sedimentation and extension may substantially predate the modern lake. These deep stratal reflections are absent in many localites, possibly on account of attenuation of the acoustic signal. However in one area of southern Lake Tanganyika, the newly-observed deep strata extend axially for ~70 km, likely representing deposits from a discrete paleolake. The high-amplitude Nyanja Event is interpreted as the onset of late-Cenozoic rifting, and the changing character of the overlying depositional sequences reflects increasing relief in the rift valley, as well as the variability of fluvial inputs, and the intermittent connectivity of upstream lake catchments. Earlier Tanganyika sequences are dominated by shallow lake and fluvial-lacustrine facies, whereas later sequences are characterized by extensive gravity flow deposition in deep water, and pronounced erosion and incision in shallow water depths and on littoral platforms. The

  15. Magmatic Versus Amagmatic Rifting in the East African Rift System from Pn and Sn Tomography

    NASA Astrophysics Data System (ADS)

    O'Donnell, J. P.; Nyblade, A.

    2014-12-01

    Geodynamic models of rifting currently rely on the mechanism of hot mantle upwelling and decompressional melting to weaken lithospheric rock to the degree that rifting can initiate. However, many rift segments worldwide are apparently amagmatic. The East African Rift System is a prime example, with large sections of the system subaerially amagmatic. We seek to address the question of whether these apparently amagmatic rift segments merely lack a surficial expression of magmatism which exists at depth, or whether rifting is genuinely amagmatic. Based on regional earthquakes recorded by the Tanzania Broadband Seismic Experiment, the Kenya Broadband Seismic Experiment, the AfricaArray East African Seismic Experiment and several permanent GSN stations, we probe for uppermost mantle melt signatures along the East African Rift System using P- and S-wave speed ratios derived from Pn and Sn tomography. Pn- and Sn-velocity models, and their ratio which can be diagnostic of the presence of fluids, will be presented.

  16. Characterization of blocks impacts from seismic signal: insights from laboratory experiments

    NASA Astrophysics Data System (ADS)

    Farin, M.; Mangeney, A.; Toussaint, R.; de Rosny, J.; Sainte-Marie, J.; Shapiro, N.

    2014-12-01

    Rockfalls, debris flows and rock avalanches represent a major natural hazard for the population in mountainous, volcanic and coastal areas but their direct observation on the field is very difficult. Recent field studies showed that gravitational instabilities can be detected, localized and characterized thanks to the seismic signal they generate. Therefore, a burning challenge for risks assessment related to these events is to obtain quantiative informations on the characteristics of the rockfalls (mass, speed, extension,...) from the properties of the signal (seismic energy, frequencies,...). Using a theoretical model of viscoelastic impact of a sphere on a plane, we develop analytical scaling laws relating the energy radiated in elastic waves, the energy dissipated in viscoelasticity during the impact and the frequencies of the generated acoustic signal to the mass m and the impact speed Vz of the sphere and to the elastic parameters of the involved materials. The elastic energy is shown to vary as m5/3Vz11/5 on plates and as mVz13/5 on blocks, regardless of the elastic parameters. The energy dissipated in viscoelasticity does not depend on the support thickness and varies as m2/3Vz11/5. The mean frequency of the generated signal is inversely proportional to the impact duration. Then, we conduct simple laboratory experiments that consist in dropping spherical beads of different size and materials and small gravels on thin plates of glass and Plexiglass and rock blocks. The elastic energy emitted by an impact on the supports is first quantitatively estimated and compared to the potential energy of fall and to the potential energy change during the shock. We observe a quantitative agreement between experimental data and the analytical scaling laws, even when we use small gravels instead of spherical beads as impactors. These experiments allows to valid the theoretical model and to establish the energy budget of an impact. In the experiments, piezoelectric

  17. Active Source Tomography of Stromboli Volcano (Italy): Results From the 2006 Seismic Experiment.

    NASA Astrophysics Data System (ADS)

    Zuccarello, L.; Patanè, D.; Cocina, O.; Castellano, M.; Sgroi, T.; Favali, P.; de Gori, P.

    2008-12-01

    Stromboli island, located in the Southern Tyrrhenian sea, is the emerged part (about 900 m a.s.l.) of a 3km-high strato-volcano. Its persistent Strombolian activity, documented for over 2000 years, is sometimes interrupted by lava effusions or major explosions. Despite the amount of recent published geophysical studies aimed to clarifying eruption dynamics, the spatial extend and geometrical characteristics of the plumbing system remain poorly understood. In fact, the knowledge of the inner structure and the zones of magma storage is limited to the upper few hundreds meters of the volcanic edifice and P- and S-waves velocity models are available only in restricted areas. In order to obtain a more suitable internal structural and velocity models of the volcano, from 25 November to 2 December 2006, a seismic tomography experiment through active seismics using air-gun sources was carried out and the final Vp model is here presented. The data has been inverted for the Vp structure by using the code Simulps13q, considering a 3D grid of nodes spaced 0.5 km down to 2 km depth, beneath the central part of volcano. The results show a relatively high velocity zones located both in the inner part of the volcanic structure, at about 1km b.s.l. and in the last 200-300 m a.s.l. in correspondence with the volcanic conduit. Slower zones were located around the summit craters in agreement with volcanological and petrological informations for the area. The relatively high velocity zones could suggest the presence of intrusive bodies related to the plumbing system.

  18. Transition from slab to slabless: Results from the 1993 Mendocino triple junction seismic experiment

    USGS Publications Warehouse

    Beaudoin, B.C.; Godfrey, N.J.; Klemperer, S.L.; Lendl, C.; Trehu, A.M.; Henstock, T.J.; Levander, A.; Holl, J.E.; Meltzer, A.S.; Luetgert, J.H.; Mooney, W.D.

    1996-01-01

    Three seismic refraction-reflection profiles, part of the Mendocino triple junction seismic experiment, allow us to compare and contrast crust and upper mantle of the North American margin before and after it is modified by passage of the Mendocino triple junction. Upper crustal velocity models reveal an asymmetric Great Valley basin overlying Sierran or ophiolitic rocks at the latitude of Fort Bragg, California, and overlying Sierran or Klamath rocks near Redding, California. In addition, the upper crustal velocity structure indicates that Franciscan rocks underlie the Klamath terrane east of Eureka, California. The Franciscan complex is, on average, laterally homogeneous and is thickest in the triple junction region. North of the triple junction, the Gorda slab can be traced 150 km inboard from the Cascadia subduction zone. South of the triple junction, strong precritical reflections indicate partial melt and/or metamorphic fluids at the base of the crust or in the upper mantle. Breaks in these reflections are correlated with the Maacama and Bartlett Springs faults, suggesting that these faults extend at least to the mantle. We interpret our data to indicate tectonic thickening of the Franciscan complex in response to passage of the Mendocino triple junction and an associated thinning of these rocks south of the triple junction due to assimilation into melt triggered by upwelling asthenosphere. The region of thickened Franciscan complex overlies a zone of increased scattering, intrinsic attenuation, or both, resulting from mechanical mixing of lithologies and/or partial melt beneath the onshore projection of the Mendocino fracture zone. Our data reveal that we have crossed the southern edge of the Gorda slab and that this edge and/or the overlying North American crust may have fragmented because of the change in stress presented by the edge.

  19. Seismic waves from elephant vocalizations: A possible communication mode?

    NASA Astrophysics Data System (ADS)

    Günther, Roland H.; O'Connell-Rodwell, Caitlin E.; Klemperer, Simon L.

    2004-06-01

    We conducted experiments with trained African elephants that show that low-frequency elephant vocalizations produce Rayleigh waves. We model a potential range for these seismic waves, under ideal conditions, of c. 2 km. In appropriate conditions, surface waves from an elephant's infrasonic vocalizations might propagate further than airborne sound and provide advantages over acoustic communication. However, if we use the detection capabilities of the human ear as a benchmark for the signal-detection thresholds of elephants, our estimates of attenuation and ambient seismic noise suggest that the seismic detection range is unlikely to exceed the acoustic detection range under normal atmospheric conditions. We conclude that elephants may benefit from seismic detection in circumstances where the range of acoustic communication is limited, or in cases where multimodal communication is advantageous. Given our current understanding, elephants are unlikely to rely on seismic waves as their primary mode for long-range communication.

  20. Factors Associated with Partnership Experiences, Attitudes, and Perceptions: A Comparative Case Study of Two African Universities

    ERIC Educational Resources Information Center

    Chiteng Kot, Felly

    2011-01-01

    International partnerships have become an increasingly important trend in African higher education. The creation of partnerships with African universities has been on the rise in the last few years. Different factors (U.S., European, and African initiatives) suggest this trend will continue to increase. This study draws from a survey of a random…

  1. Contributions of College Experiences to African American and White Graduates' Careers.

    ERIC Educational Resources Information Center

    Nickols, Sharon Y.; And Others

    1996-01-01

    A survey of housing/consumer economics and social work alumni received responses from 38 African American and 50 white graduates. Likely sources of financial support for whites were parents, and for African Americans, grants. African Americans had significantly higher social support from churches, whites from sororities/fraternities. There were no…

  2. Comparison of abuse experiences of rural and urban African American women during perinatal period.

    PubMed

    Bhandari, Shreya; Bullock, Linda F C; Richardson, Jeanita W; Kimeto, Pamela; Campbell, Jacquelyn C; Sharps, Phyllis W

    2015-07-01

    A subsample of 12 African American women (6 urban and 6 rural) were selected from a larger longitudinal, randomized control trial, Domestic Violence Enhanced Home Visitation (DOVE-R01 900903 National Institute of Nursing Research [NINR]/National Institutes of Health [NIH]). All African American women were chosen to control for any racial- and/or race-related cultural differences that may exist among women across geographical areas. The experiences of abuse during the perinatal period are drawn from in-depth interviews conducted at five points in time during pregnancy and the post-partum period. The analysis describes three major themes that highlight the similarities and differences among rural and urban women. The main themes found were (1) types of abuse, (2) location of abuse, and (3) response to abuse. In addition, two sub-themes (a) defiance and compliance and (b) role of children were also identified. Implications for universal screening for women of reproductive age, safer gun laws, and the need for further research are discussed. PMID:25315478

  3. Regulatory challenges for GM crops in developing economies: the African experience.

    PubMed

    Nang'ayo, Francis; Simiyu-Wafukho, Stella; Oikeh, Sylvester O

    2014-12-01

    Globally, transgenic or genetically modified (GM) crops are considered regulated products that are subject to regulatory oversight during trans-boundary movement, testing and environmental release. In Africa, regulations for transgenic crops are based on the outcomes of the historic Earth Summit Conference held in Rio, Brazil two decades ago, namely, the adoption of the Convention on Biological Diversity (CBD) and the subsequent adoption of the Cartagena Protocol on Biosafety. To exploit the potential benefits of transgenic crops while safeguarding the potential risks on human health and environment, most African countries have signed and ratified the CBD and the Cartagena Protocol on Biosafety. Consequently, these countries are required to take appropriate legal, administrative and other measures to ensure that the handling and utilization of living modified organisms are undertaken in a manner that reduces the risks to humans and the environment. These countries are also expected to provide regulatory oversight on transgenic crops through functional national biosafety frameworks (NBFs). While in principle this approach is ideal, NBFs in most African countries are steeped in a host of policy, legal and operational challenges that appear to be at cross-purposes with the noble efforts of seeking to access, test and deliver promising GM crops for use by resource-limited farmers in Africa. In this paper we discuss the regulatory challenges faced during the development and commercialization of GM crops based on experiences from countries in Sub-Saharan Africa.

  4. Comparison of Abuse Experiences of Rural and Urban African American Women During Perinatal Period

    PubMed Central

    Bhandari, Shreya; Bullock, Linda F. C.; Richardson, Jeanita W.; Kimeto, Pamela; Campbell, Jacquelyn C.; Sharps, Phyllis W.

    2015-01-01

    A subsample of 12 African American women (6 urban and 6 rural) were selected from a larger longitudinal, randomized control trial, Domestic Violence Enhanced Home Visitation (DOVE-R01 900903 National Institute of Nursing Research [NINR]/National Institutes of Health [NIH]). All African American women were chosen to control for any racial- and/or race-related cultural differences that may exist among women across geographical areas. The experiences of abuse during the perinatal period are drawn from in-depth interviews conducted at five points in time during pregnancy and the post-partum period. The analysis describes three major themes that highlight the similarities and differences among rural and urban women. The main themes found were (1) types of abuse, (2) location of abuse, and (3) response to abuse. In addition, two sub-themes (a) defiance and compliance and (b) role of children were also identified. Implications for universal screening for women of reproductive age, safer gun laws, and the need for further research are discussed. PMID:25315478

  5. The South African Experience of Conservation and Social Forestry Outreach Nurseries

    NASA Astrophysics Data System (ADS)

    Botha, Jenny; Witkowski, Ed T. F.; Cock, Jacklyn

    2006-11-01

    Outreach nurseries are favored conservation and social forestry tools globally, but, as with many integrated conservation and development programs (ICDPs), they do not always produce anticipated results. A synopsis of the experience of South African practitioners is provided in this study of 65 outreach nurseries. South African outreach nurseries frequently include financial objectives, creating additional challenges in simultaneously attaining conservation and socioeconomic goals. Progress was hindered by biophysical problems (e.g., lack of water, poor soils, etc.) as well as the harsh socioeconomic conditions facing most communities in which nurseries had been established. Attaining financial viability was challenging. Business management skills were often restricted, and few viability studies included adequate market research. Costs to community participants were usually high, and benefits were limited. Conservation objectives were frequently lost in the struggle to attain financial viability. The management of social processes also proved challenging. Although small scale and relatively straightforward compared with many ICDPs, nurseries usually require substantial institutional support, including a range of technical, business, and development services. Project time frames need to be reconsidered, as practitioners estimate that it takes 5-10 years for nurseries to start meeting objectives, and donors and implementing agencies often operate on 2-3-year project cycles. Detailed viability studies are essential, incorporating a social probe and an assessment of potential impacts of projects on community participants. Progress needs to be continuously evaluated to enable institutions and community participants to adapt to changing conditions as well as ensure that the spectrum of objectives are being achieved.

  6. Regional Seismic Signals from Chemical Explosions, Nuclear Explosions and Earthquakes: Results from the Arizona Source Phenomenology Experiment

    SciTech Connect

    Walter, W R; Gok, R; Mayeda, K; Sicherman, A; Bonner, J; Leidig, M

    2005-09-02

    Routine industrial mining explosions play two important roles in seismic nuclear monitoring research: (1) they are a source of background events that need to be discriminated from potential nuclear explosions; (2) as some of the only explosions occurring in the current de facto global moratoria on nuclear testing, their signals should be exploited to improve the calibration of seismic m monitoring systems. A common issue monitoring arising in both of these roles is our limited physical understanding of the causes behind observed differences and similarities in the seismic signals produced by routine industrial mining blasts and small underground nuclear tests. In 2003 a consortium (Weston, SMU, LLNL, LANL and UTEP) carried out a Source Phenomenology Experiment (SPE), a series of dedicated explosions designed to improve this physical understanding, particularly as it relates to seismic methods of discriminating between signals from three different source types: earthquakes, industrial blasts, and nuclear tests. Here we very briefly review prior field experimental work that examined the seismic relationships between these source types.

  7. The effect of deformation history on the interpretation of seismic anisotropy in the upper mantle: experiments and numerical modeling

    NASA Astrophysics Data System (ADS)

    Boneh, Y.; Skemer, P. A.; Morales, L. F. G.; Kaminski, E. C.

    2015-12-01

    The main source of seismic anisotropy in the upper mantle is the deformation-induced crystallographic preferred orientation (CPO) of olivine. The interpretation of seismic anisotropy relies on models and experiments that predict certain relationships between olivine CPO and the deformation kinematics. Under some conditions, such as the interiors of oceanic plates, these relationships may be quite simple. However, near plate boundaries flow patterns are complex and the interpretation of seismic anisotropy is not straight-forward. In this contribution we describe the effect of deformation history on the re-orientation of olivine CPO as a function of strain. High pressure and temperature deformation experiments were performed on the Åheim dunite, which exhibits a pre-existing texture. Experiments were conducted in three different configurations with the pre-existing foliation at 0°, 45°, and 90° to the axis of compression, simulating three unique deformation histories. Deformation microstructures and texture are analyzed using electron backscatter diffraction (EBSD). The experiments show that up to strains of ~0.7 the three configurations evolve differently from one another, and from models initiated with random textures. Moreover, none of the models achieved the expected textural steady-state. The experiments results are then compared to numerical simulations using a Viscoplastic Self Consistent (VPSC) approach, and D-Rex. The input for the models is the Åheim dunite CPO in the three configurations used in the experiments. It is shown that, generally, texture symmetry evolves similarly in the models and the experiments although there are notable differences in texture strength. To achieve better agreement between experiments and models, new model parameterizations are proposed. Finally, we use the new parameterization of D-Rex to simulate a range of plausible deformation histories and associated seismic anisotropy in a variety of flow settings.

  8. A deep towed explosive source for seismic experiments on the ocean floor

    NASA Astrophysics Data System (ADS)

    Koelsch, Donald E.; Witzell, Warren E.; Broda, James E.; Wooding, Frank B.; Purdy, G. M.

    1986-12-01

    A new seismic source for carrying out high resolution measurements of deep ocean crustal structure has been constructed and successfully used in a number of ocean bottom refraction experiments on the Mid Atlantic Ridge near 23° N. The source is towed within 100 m of the ocean floor on a conventional 0.68″ coaxial cable and is capable of firing, upon command from the research vessel, up to 48 individual 2.3 kg explosive charges. The explosive used was commercially available Penta-Erythritol-Tetra Nitrate (PETN) that was activated by 14.9 gm m-1 Primacord and DuPont E-97 electrical detonators. For safety reasons each detonator was fitted with a pressure switch that maintained a short until the source was at depth in excess of approximately 300 m. In addition, a mechanical protector isolated the detonator from the main charge and was only removed by the physical release of the explosive from the source package. These and other safety precautions resulted in several misfires but three experiments were successfully completed during the summer of 1985 at source depths of 3000 4000 m.

  9. Seafloor bathymetry and gravity from the ALBACORE marine seismic experiment offshore southern California

    NASA Astrophysics Data System (ADS)

    Shintaku, N.; Weeraratne, D. S.; Kohler, M. D.

    2010-12-01

    Although the North America side of the plate boundary surrounding the southern California San Andreas fault region is well studied and instrumented, the Pacific side of this active tectonic boundary is poorly understood. In order to better understand this complex plate boundary offshore, its microplate structures, deformation, and the California Borderland formation, we have recently conducted the first stage of a marine seismic experiment (ALBACORE - Asthenospheric and Lithospheric Broadband Architecture from the California Offshore Region Experiment) deploying 34 ocean bottom seismometers offshore southern California in August 2010. We present preliminary data consisting of seafloor bathymetry and free air gravity collected from this experiment. We present high-resolution maps of bathymetry and gravity from the ALBACORE experiment compiled with previous ship track data obtained from the NGDC (National Geophysical Data Center) and the USGS. We use gravity data from Smith and Sandwell and study correlations with ship track bathymetry data for the features described below. We observe new seafloor geomorphological features far offshore and within the Borderland. Steep canyon walls which line the edges of the Murray fracture zone with possible volcanic flows along the canyon floor were mapped by multibeam bathymetry for the first time. Deep crevices juxtaposed with high edifices of intensely deformed plateaus indicate high strain deformation along the arcuate boundary of the Arguello microplate. Small volcanic seamounts are mapped which straddle the Ferrelo fault (Outer Borderland) and San Pedro fault (Inner Borderland), and appear to exhibit fracture and fault displacement of a portion of the volcanic centers in a left-lateral sense. A large landslide is also imaged extending approximately 6 miles in length and 3 miles in width in the Santa Cruz basin directly south of Santa Rosa Island. Deformation associated with capture of Arguello and Patton microplates by the

  10. Evaluation and developmental studies of possible active seismic experiments during the post-Apollo period

    NASA Technical Reports Server (NTRS)

    Kovach, R. L.

    1974-01-01

    Seismic velocity studies pertinent to the lunar crust and mantle are briefly summarized. The compressional and shear wave velocities in loose aggregates are discussed along with the effects of temperature on seismic velocity in compacted powders. Abstracts of papers concerning the lunar structure are included.

  11. Early educational foundations for the development of civic responsibility: an African experience.

    PubMed

    Serpell, Robert; Mumba, Paul; Chansa-Kabali, Tamara

    2011-01-01

    An innovative curriculum designed to foster the development of social responsibility among pre-adolescent children was introduced at a rural Zambian primary school. The curriculum invoked Child-to-Child principles focusing on health education, advancing a synthesis of Western psychological theories and African cultural traditions. The teacher sought to democratize the educational process through cooperative learning in mixed-gender, mixed-social-class, and mixed-ability study groups. Learners engaged in community service activities and contributed to the nurturant care of younger children. Young adults interviewed seventeen years after completing the program recalled their experience and reflected on how it had promoted their personal agency, cooperative disposition, and civic responsibility in early adulthood.

  12. “I thought we are safe”: Southern African lesbians' experiences of living with HIV

    PubMed Central

    Matebeni, Zethu; Reddy, Vasu; Sandfort, Theo; Southey-Swartz, Ian

    2013-01-01

    HIV prevention and service programmes have long either ignored or overlooked lesbians. The experiences of lesbians with HIV have similarly been unrecognised and unreported. This erasure has contributed to the invisibility of lesbians in relation to HIV and related health risks. This community participatory study, based on in-depth interviews with twenty-four self-identifying African lesbians living with HIV in South Africa, Zimbabwe and Namibia, focuses on their personal experiences and circumstances. Women's experiences shed light and challenge popular notions around lesbian risk. In particular among this group are lesbians who self-report exclusive sexual relationships with women. For these women, experiences of living with HIV are challenging as they struggle to understand the possibility of female-to-female transmission. While battling with their own perceptions of invulnerability and accepting their HIV positive status, they have to deal also with wide-ranging misconceptions about risk. The paper argues that within the context of HIV lesbians cannot be regarded as a `no-risk' group. Health services and health providers are encouraged to respond to the health needs of lesbians living with HIV. PMID:23627778

  13. Siting of USArray Seismic Stations in North Carolina and southern Virginia: Experience of NC-1 Team

    NASA Astrophysics Data System (ADS)

    Martin, P.; Howard, J.; Horne, T.

    2012-12-01

    The USArray component of the EarthScope, a transportable array of 400 seismometers installed in a grid about 70 km apart, is in the next two years entering its final stage with station deployment along the Atlantic coast of the United States. Here, we present the experience of the student-faculty team from North Carolina Central University (NCCU) in finding and documenting the suitable sites for the twenty five USArray stations in North Carolina and southern Virginia. The ideal sites are easily accessible yet far from traffic and other sources of noise, with good cell phone coverage, sun exposure and out of flood-prone areas. Although the initial selection of potential locations was done using geospatial mapping and analysis software provided by EarthScope, finding and finalizing the sites involved driving more then 1,000 miles each week for over two months inspecting possible site locations. Aside from driving, the majority of time was spent talking about the EarthScope project and hosting of USArray stations to mostly reluctant landowners. In addition to facing various challenges in finding appropriate sites due to land use issues, such as suburban sprawl of central North Carolina, or topography factors, such as low lying flood prone coastal areas, by far the major challenge was finding the landowners willing to host the seismic station for the necessary three years. In addition to involving students from an HBCU in seismology related project and increasing the visibility of NCCU geophysics program in the University and local community through publicity releases in local media and on university web site, the project had an important outreach component. As North Carolina is located along the seismically quiet, passive Atlantic margin, most residents are not familiar with earthquakes and seismology and the siting experience provided students an opportunity to practice explaining the earthquake research to the general public. The dialog also highlighted science

  14. The Seismic Aftershock Monitoring System (SAMS) for OSI - Experiences from IFE14

    NASA Astrophysics Data System (ADS)

    Gestermann, Nicolai; Sick, Benjamin; Häge, Martin; Blake, Thomas; Labak, Peter; Joswig, Manfred

    2016-04-01

    An on-site inspection (OSI) is the third of four elements of the verification regime of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The sole purpose of an OSI is to confirm whether a nuclear weapon test explosion or any other nuclear explosion has been carried out in violation of the treaty and to gather any facts which might assist in identifying any possible violator. It thus constitutes the final verification measure under the CTBT if all other available measures are not able to confirm the nature of a suspicious event. The Provisional Technical Secretariat (PTS) carried out the Integrated Field Exercise 2014 (IFE14) in the Dead Sea Area of Jordan from 3 November to 9. December 2014. It was a fictitious OSI whose aim was to test the inspection capabilities in an integrated manner. The technologies allowed during an OSI are listed in the Treaty. The aim of the Seismic Aftershock Monitoring System (SAMS) is to detect and localize aftershocks of low magnitudes of the triggering event or collapses of underground cavities. The locations of these events are expected in the vicinity of a possible previous explosion and help to narrow down the search area within an inspection area (IA) of an OSI. The success of SAMS depends on the main elements, hardware, software, deployment strategy, the search logic and not least the effective use of personnel. All elements of SAMS were tested and improved during the Built-Up Exercises (BUE) which took place in Austria and Hungary. IFE14 provided more realistic climatic and hazardous terrain conditions with limited resources. Significant variations in topography of the IA of IFE14 in the mountainous Dead Sea Area of Jordan led to considerable challenges which were not expected from experiences encountered during BUE. The SAMS uses mini arrays with an aperture of about 100 meters and with a total of 4 elements. The station network deployed during IFE14 and results of the data analysis will be presented. Possible aftershocks of

  15. Crustal structure beneath the Rif Cordillera, North Morocco, from the RIFSIS wide-angle reflection seismic experiment

    NASA Astrophysics Data System (ADS)

    Gil, Alba; Gallart, Josep; Diaz, Jordi; Carbonell, Ramon; Torne, Montserrat; Levander, Alan; Harnafi, Mimoun

    2014-12-01

    different geodynamic models proposed since the late 1990s to account for the complex evolution of the Gibraltar Arc System lack definite constraints on the crustal structure of the Rif orogen. Here we present the first well-resolved P-wave velocity crustal models of the Rif Cordillera and its southern continuation toward the Atlas made using controlled-source seismic data. Two 300+ km-long wide-angle reflection profiles crossed the Rif along NS and EW trends. The profiles recorded simultaneously five land explosions of 1Tn each using ˜850 high frequency seismometers. The crustal structure revealed from 2-D forward modeling delineates a complex, laterally varying crustal structure below the Rif domains. The most surprising feature, seen on both profiles, is a ˜50 km deep crustal root localized beneath the External Rif. To the east, the crust thins rapidly by 20 km across the Nekkor fault, indicating that the fault is a crustal scale feature. On the NS profile the crust thins more gradually to 40 km thickness beneath Middle Atlas and 42 km beneath the Betics. These new seismic results are in overall agreement with regional trends of Bouguer gravity and are consistent with recent receiver function estimates of crustal thickness. The complex crustal structure of the Rif orogen in the Gibraltar Arc is a consequence of the Miocene collision between the Iberian and African plates. Both the abrupt change in crustal thickness at the Nekkor fault and the unexpectedly deep Rif crustal root can be attributed to interaction of the subducting Alboran slab with the North African passive margin at late Oligocene-early Miocene times.

  16. Schooling Experiences and Perceptions of Resettled Sub-Saharan African Refugee Middle School Students in a Southwest U.S. State

    ERIC Educational Resources Information Center

    Sallu, Adama

    2012-01-01

    This study examined the schooling experiences and perceptions of resettled sub-Saharan African middle school refugee students in a metropolitan area of the United States Southwest. The research questions underpinning this study included: What are the schooling experiences and perceptions of resettled sub-Saharan African middle school refugee…

  17. A Case Study: How Do Social and Academic Experiences of African American Nontraditional Female Students on HBCU Campuses Influence Their Motivation to Graduate?

    ERIC Educational Resources Information Center

    Jackson-Golden, Cheryl D.

    2013-01-01

    Through a qualitative collective case study research design, the study captured the social and academic experiences of 13 African American nontraditional undergraduate female students enrolled in a historically Black college campus (HBCU) located in the southern United States. Experiences of 13 African American nontraditional undergraduate female…

  18. The stage-specific role of spirituality among African American Christian women throughout the breast cancer experience.

    PubMed

    Simon, Cassandra E; Crowther, Martha; Higgerson, Hyoun-Kyoung

    2007-01-01

    This study presents the results of semistructured interviews conducted with 18 African American Christian women regarding the role of spirituality throughout their breast cancer experiences. The spiritual themes relevant for phases of the breast cancer experience are identified. Analysis resulted in the identification of 11 codes and 5 subcodes that corresponded to the diagnosis, treatment, and posttreatment phases of the breast cancer experience. Most of the survivors indicated that their spirituality and faith assisted them throughout the breast cancer experience. Discussion focuses on the spiritual resources used by the participants at the different stages in the breast cancer experience. Attention is given to implications for how professionals can use these resources to assist African American women coping with breast cancer.

  19. Mid-Ocean Ridge Mantle Processes Constrained by the FAIM Seismic Refraction Experiment

    NASA Astrophysics Data System (ADS)

    Collins, J. A.; Lizarralde, D.; Gaherty, J. B.; Hirth, G.; Kim, S.

    2003-12-01

    The seismic structure (e.g. velocity, velocity gradients, anisotropy) of the shallow upper mantle of oceanic lithosphere constrains the degree of melt extraction at mid-ocean ridges and the shear deformation of the lithosphere. The variation of fine-scale structure with depth is difficult to resolve with teleseismic data but, with some notable exceptions, seismic refraction techniques - which have excellent depth resolution - have not been used to elucidate oceanic upper mantle structure. Here we report further results from the FAIM (Far-offset Active-source Imaging of the Mantle) seismic refraction experiment conducted along an 800-km-long flow-line transect and a 150-km-long ridge-parallel transect in the western north Atlantic. Sixteen short-period, vertical-component ocean-bottom seismometers (OBS) were deployed along the spreading-parallel transect in 3-km-separated pairs spaced 80-120 km apart, and 3 OBS were deployed orthogonal to the primary transect to a maximum distance of 350 km. Shot spacing was 1 km. Coherent P-wave arrivals were observed to 350-km distance, and the amplitude of this phase and its increasing and fast apparent-velocity suggest that energy is propagating to ˜24 km depth below the Moho. Two-dimensional travel-time analyses predict velocities of ˜8.25-8.55 km/s over the uppermost 24 km of the mantle on the flow-line-parallel transect and velocities of ˜8.05-8.25 km/s over the uppermost 10 km of the mantle on the ridge-parallel transect. At face value, these values indicate P-wave anisotropy is at least ˜3.0% throughout the upper 10 km of the mantle. However, velocities in only two orthogonal directions cannot constrain the precise direction and magnitude of anisotropy. To improve this estimate we analyzed the travel times of P-waves with good signal to noise from shots at ranges of 75-250 km, with an azimuth range spanning ˜100\\deg. When plotted as a function of propagation azimuth, these travel times display a strong variation, with

  20. Conceptual Design and Architecture of Mars Exploration Rover (MER) for Seismic Experiments Over Martian Surfaces

    NASA Astrophysics Data System (ADS)

    Garg, Akshay; Singh, Amit

    2012-07-01

    Keywords: MER, Mars, Rover, Seismometer Mars has been a subject of human interest for exploration missions for quite some time now. Both rover as well as orbiter missions have been employed to suit mission objectives. Rovers have been preferentially deployed for close range reconnaissance and detailed experimentation with highest accuracy. However, it is essential to strike a balance between the chosen science objectives and the rover operations as a whole. The objective of this proposed mechanism is to design a vehicle (MER) to carry out seismic studies over Martian surface. The conceptual design consists of three units i.e. Mother Rover as a Surrogate (Carrier) and Baby Rovers (two) as seeders for several MEMS-based accelerometer / seismometer units (Nodes). Mother Rover can carry these Baby Rovers, having individual power supply with solar cells and with individual data transmission capabilities, to suitable sites such as Chasma associated with Valles Marineris, Craters or Sand Dunes. Mother rover deploys these rovers in two opposite direction and these rovers follow a triangulation pattern to study shock waves generated through firing tungsten carbide shells into the ground. Till the time of active experiments Mother Rover would act as a guiding unit to control spatial spread of detection instruments. After active shock experimentation, the babies can still act as passive seismometer units to study and record passive shocks from thermal quakes, impact cratering & landslides. Further other experiments / payloads (XPS / GAP / APXS) can also be carried by Mother Rover. Secondary power system consisting of batteries can also be utilized for carrying out further experiments over shallow valley surfaces. The whole arrangement is conceptually expected to increase the accuracy of measurements (through concurrent readings) and prolong life cycle of overall experimentation. The proposed rover can be customised according to the associated scientific objectives and further

  1. Characterization and comparison of seismic signals emitted during field scale sheer box experiments and artificially induced landslides

    NASA Astrophysics Data System (ADS)

    Yfantis, Georgios; Martinez Carvajal, Hernan Eduardo; Pytharouli, Stella; Lunn, Rebecca

    2014-05-01

    The identification and detection of landslide induced seismic signals, recorded by deployed seismometers on active landslides has been the subject of many studies. The most commonly faced problem is the uncertainty in identifying which of the recorded signals are representing a movement or a failure in the landslide's body. In this paper we present two novel experimental campaigns; 1) field scale laboratory experiments of a 65cm diameter sheer box, 2) artificially induced failure of two, two-meter high vertical soil slopes. Using a field scale sheer box we recorded seismic signals emitted during soil slippage events, a phenomenon observed at a landslide's failure plain. This was implemented by displacing, a few centimeters at a time (1-10cm), a concrete cylinder filled with soil along a corridor free from vegetation. The field scale sheer box methodology allows control over a large number of parameters that affect a landslide. For example, it is possible to control soil saturation thus simulating different rain events or control the stress field on the soil's slippage surface simulating displacement events at different depths. More than 40 displacement events were induced under four different loading conditions between 472kg to 829kg. All soil slippage events were recorded above the levels of background seismic noise. Repetition of the methodology under the same experimental conditions resulted in similar seismic signals allowing us to define a 'characteristic seismic response' for soils. In the second experimental campaign, two controlled landslides were experimentally induced by increasing the vertical load on top of a 2m soil scarp. We were able to detect from 1 to 10 centimeter wide crack propagations and displacements, and approximately 20x20x10cm to 100x50x20cm block failure events based on microseismic recordings, field notes, video recordings and displacement measurements of the landslide's crown that failed during the experiments. Direct correlation

  2. Resistance and Assent: How Racial Socialization Shapes Black Students' Experience Learning African American History in High School

    ERIC Educational Resources Information Center

    Thornhill, Theodore E.

    2016-01-01

    African American history is often taught poorly in high school U.S. history courses. However, we know little about how Black students perceive and experience this situation. I use a refined racial socialization framework and interview data with 32 Black college students in the Northeast to investigate how familial racial socialization shapes their…

  3. Sex-Role Egalitarian Attitudes and Gender Role Socialization Experiences of African American Men and Women: A Mixed Methods Paradigm

    ERIC Educational Resources Information Center

    Heard, Courtney Christian Charisse

    2013-01-01

    The purpose of this study was to assess the sex-role egalitarian attitudes and gender role socialization experiences of African American men and women. A sequential mixed-methods design was employed to research this phenomenon. The Sex-Role Egalitarianism Scale-Short Form BB (SRES-BB) was utilized to assess sex-role egalitarian attitudes (King…

  4. A New Generation of Large Seismic Refraction Experiments in Central Europe (1997-2003)

    NASA Astrophysics Data System (ADS)

    Guterch, A.; Grad, M.; Spicak, A.; Brueckl, E.; Hegedus, E.; Keller, G. R.; Thybo, H.

    2003-12-01

    Beginning in 1997, Central Europe has been covered by an unprecedented network of seismic refraction experiments. These experiments (POLONAISE'97, CELEBRATION 2000, ALP 2002, SUDETES 2003) have only been possible due a massive international cooperative effort. The total length of all profiles is about 19,000 km, and over 300 explosive sources were employed. The result is a network of seismic refraction profiles that extends along the Trans-European Suture Zone region of Poland and the Bohemian massif, Pannonian basin, trough the Carpathians and Alps to the Adriatic Sea and the Dinarides. As reflected in structures within these areas, Central Europe has experienced a complex tectonic history that includes the Caledonian, Variscan, and Alpine orogenies. The related TESZ region is a broad zone of deformation that extends across Europe from British Isles to the Black Sea region that formed as Europe was assembled from a complex collage of terranes during the late Palaeozoic. For example, the Bohemian massif is mostly located in the Czech Republic and is a large, complex terrane whose origin can be traced to northern Gondwana (Africa). These terranes were accreted along the margin of Baltica that was formed during the break-up of Rodinia. The tectonic evolution of this region shares many attributes with the Appalachian/Ouachita origin and is certainly of global important to studies in terrane tectonics and continental evolution. In southern Poland, several structural blocks are located adjacent to Baltica and were probably transported laterally along it similar to the Cenozoic movement of terranes along the western margin of North America. The younger Carpathian arc and Pannonian back-arc basin were also targeted by these experiments. Thickness of the crust in the area of investigations changes from 22-25 km in the Pannonian basin to about 55 km in the Trans-European Suture Zone in SE Poland. Together, these experiments are providing an unprecedented 3-D image of the

  5. Frictional behavior of talc at seismic slip rates: preliminary results from high-velocity experiments.

    NASA Astrophysics Data System (ADS)

    Boutareaud, S.; Hirose, T.; Doan, M. L.; Andréani, M.; Calugaru, D. G.

    2009-04-01

    Talc is one of the few minerals not following the Byerlee law, its static friction velocity is 0.2-0.25. Talc has been identified in the San Andreas Fault, and is expected to occur within subduction zone. Talc can then affect their seismic behavior. Yet, the details of its frictional properties are poorly known, especially at seismic velocities. Our study aims at understanding its behavior at these velocities. The properties of the talc were studied during high-velocity rotary-shear experiments carried out at from 0.01 m/s to 1.31 m/s, at normal stresses of 0.6 to 1.4 MPa, using the frictional testing apparatus of the JAMSTEC. The experimental gouge is a pure natural talc schist powder (99.9% wt). The samples were test used in dry (i.e. at room moisture conditions) or wet conditions. During experiments, we were able to measure simulated fault thickness evolution, moisture release and to calculate friction coefficient. Even though it is from the start a weak material, talc schist follows a slip weakening law, which appears to depend strongly on the saturation of the sample. Dry samples sliding at speed of 1.31m/s an exponential decrease of friction coefficient from a peak value of 0.98-0.71 to a steady state value between 0.18 and 0.59. This weakening is strongly dependent on normal stress. Dry sample also experienced large gouge dilation. Results from experiments on wet samples are different. The friction peak values of 0.52-0.36 drop to a steady state value between 0.1 and 0.18. Moreover the steady state friction seems to be independent on the applied normal stress. Finally, the wet samples do not experience dilation, but a large release of water steam. This preliminary work suggests two different weakening processes for dry and wet conditions, respectively. To understand the talc friction behavior, we performed studies on talc schist decomposition, in case flash heating would locally alter the talc structure. Differential thermal analysis (DTA) combined to

  6. Structural evolution of the Rides Prerifaines (Morocco): structural and seismic interpretation and analogue modelling experiments

    NASA Astrophysics Data System (ADS)

    Sani, F.; Del Ventisette, C.; Montanari, D.; Bendkik, A.; Chenakeb, M.

    2007-08-01

    The Rides Prerifaines (RP) of Morocco constitute the leading edge of the Rif chain. They involve a Triassic Palaeocene succession deposited on a peneplained Palaeozoic fold belt and accumulated in basins delimited by NE SW-trending normal fault systems. A significant hiatus separates an overlying Middle Miocene Upper Miocene foredeep sequence. The reconstruction of the complex structural evolution of the RP during the later compressive phases that affected the Rif chain since Middle Miocene time has been the aim of this paper. We integrated field structural analyses, seismic line interpretation, and analogue modelling in order to evaluate the control exerted by the Late Triassic Jurassic normal fault systems onto the later compressive tectonics. The maximum compression direction associated with the first compressive phase is roughly NE SW to ENE WSW oriented. During this phase the Mesozoic basin fill was scooped-out from the graben and the main décollement level were the Triassic evaporites. Since Pliocene times the maximum compression direction was oriented roughly N S. During this phase the RP assumed their present structural setting. The earlier normal faults delimiting the Mesozoic graben were reactivated in a strike slip mode also involving the Palaeozoic basement. The analogue modelling experiments demonstrated that the basement reactivation promoted salt tectonics and favoured fluid circulation.

  7. A decade of experience with renal transplantation in African-Americans.

    PubMed

    Foster, Clarence E; Philosophe, Benjamin; Schweitzer, Eugene J; Colonna, John O; Farney, Alan C; Jarrell, Bruce; Anderson, Leslie; Bartlett, Stephen T

    2002-12-01

    OBJECTIVE To evaluate the strategies instituted by the authors' center to decrease the time to transplantation and increase the rate of transplantation for African-Americans, consisting of a formal education program concerning the benefits of living organ donation that is oriented to minorities; a laparoscopic living donation program; use of hepatitis C-positive donors in documented positive recipients; and encouraging vaccination for hepatitis B, allowing the use of hepatitis B core Ab-positive donors. SUMMARY BACKGROUND DATA The national shortage of suitable kidney donor organs has disproportional and adverse effects on African-Americans for several reasons. Type II diabetes mellitus and hypertension, major etiologic factors for end-stage renal disease, are more prevalent in African-Americans than in the general population. Once kidney failure has developed, African-Americans are disadvantaged for the following reasons: this patient cohort has longer median waiting times on the renal transplant list; African-Americans have higher rates of acute rejection, which affects long-term allograft survival; and once they are transplanted, the long-term graft survival rates are lower in this population than in other groups. METHODS From March 1990 to November 2001 the authors' center performed 2,167 renal transplants; 944 were in African-Americans (663 primary cadaver renal transplants and 253 primary Living donor renal transplants). The retransplants consisted of 83 cadaver transplants and 17 living donor transplants. Outcome measures of this retrospective analysis included median waiting time, graft and patient survival rates, and the rate of living donation in African-Americans and comparable non-African-Americans. Where applicable, data are compared to United Network for Organ Sharing national statistics. Statistical analysis employed appropriate SPSS applications. RESULTS One- and 5-year patient survival rates for living donor kidneys were 97.1% and 91.3% for non-African

  8. Establishing of cancer units in low or middle income african countries: angolan experience - a preliminary report

    PubMed Central

    Miguel, Fernando; Conceição, Ana Vaz; Lopes, Lygia Vieira; Bernardo, Dora; Monteiro, Fernando; Bessa, Fernanda; Santos, Cristina; Oliveira, João Blasques; Santos, Lúcio Lara

    2014-01-01

    Introduction The number of cancer cases and related deaths worldwide is expected to double over the next 20-30 years. African countries will be the most affected by the burden of cancer. The improving economic situation of Angola creates conditions for an increase in life expectancy which by itself is associated with an increased risk of oncological diseases. Because cancer therapy requires a multidisciplinary approach, trained health professionals, satisfactory infrastructure and appropriate facilities, the availability of effective cancer therapy is a difficult task that requires support. The aim of this article is to share our experience achieved in the establishment of cancer units in Angola and to validate our checklist for this action. Methods The survey method was a questionnaire addressed to Angolan cancer units, in order to evaluate the usefulness and feasibility of a checklist developed by the authors - The Cancer Units Assessment Checklist for low or middle income African countries - which was used previously in the establishment of those units. Afterwards, the crucial steps taken for the establishing of the main sites of each cancer unit considering, facilities, resources and professionals, were also recorded. Results All cancer units reported that the checklist was a useful tool in the development of the cancer program for the improvement of the unit or the establishing of cancer unit sites. This instrument helped identifying resources, defining the best practice and identifying barriers. Local experts, who know the best practices in oncology and who are recognized by the local heads, are also important and they proved to be the major facilitators. Conclusion The fight against cancer has just started in Angola. The training, education, advocacy and legislation are ongoing. According to our results, the assessment checklist for the establishment of cancer units is a useful instrument. PMID:25883719

  9. The High Lava Plains Broadband Seismic Experiment: Objectives, Status and Preliminary Results

    NASA Astrophysics Data System (ADS)

    James, D. E.; Fouch, M.; Eager, K.; Nair, S.; Roth, J.; Warren, L.; Beghein, C.; West, J.; Carlson, R.; Johnson, J.; Golden, S.

    2006-12-01

    The High Lava Plains (HLP) Project is a multi-disciplinary program to study the structure and formation of the high lava plains volcanic lineament, the most prominent feature of the actively evolving continental lithosphere in central and eastern Oregon. This region in the Pacific Northwest represents one of the most accessible, yet least understood, examples worldwide of the tectonomagmatic consequences of plate margin restructuring on the development of continental lithosphere. The confusing and complex tectonomagmatic evolution there has been variously ascribed to the Yellowstone plume, back-arc subduction processes, Basin and Range extension, or asthenospheric inflow along the migrating edge of the descending Juan de Fuca (formerly Farallon) plate. Various aspects of each of these processes are either mutually exclusive or apparently inconsistent with observations, but the seismic data that could resolve key questions of tectonomagmatic development have been conspicuously absent. The HLP Seismic Experiment is organized around multi-level broadband and active source seismic studies of the crust and mantle beneath young continent now largely blanketed with late Cenozoic volcanic rocks. The dense broadband array, when fully configured, will consist of about 170 stations in a region ~ 500 x 350 km. The high station density will make it possible to resolve fine-scale structures in the crust and mantle beneath the extensive region of post-17 Ma volcanism and at its margins with Proterozoic North America, the Northern Great Basin, and Cascadia with detail well beyond the capabilities of the more sparse EarthScope USArray Transportable Array. Synthetic resolution tests of tomographic images demonstrate sharply contrasting capabilities between the two arrays, particularly for imaging localized low-velocity features in the uppermost mantle. While the full HLP array is not scheduled for deployment until late spring, 2007, the installation of a skeletal array began in

  10. Seismic and Climatic Anomalies and Earthquakes Possibly Correlated to Electromagnets of LHC Project Experiment Processes

    NASA Astrophysics Data System (ADS)

    Sengor, T.

    2009-04-01

    The electromagnetic fields, which are generated by the electromagnets used in accelerating and redirecting the particles during the LHC experiment of CERN, can redirect both of the earthquake processes and climatic events what the Earth has. Besides, this EM field can trigger the uncaused major and big earthquakes, natural hazards generated due to atmospheric phenomena all around the Globe, potentially. So that, these uncausality effects may not be involved and processed in current possible expectation calculations, observations, probabilitistical approaches related to earthquakes and climatic hazards as great floods, thunderstorms, outbreaks, catastrophes, and etc. These results may occur after the experiment was ended, too. This paper aims a better understanding of the physical mechanisms through theoretical and/or observational studies including modeling of possible correlations related to the interactions of the electromagnetic field and/or wave sources with the seismic and/or climatic phenomena. Whole of the Earth should be considered as one, but complex system up to the outer space from the center of the globe to understand the compact reasons behind the natural phenomena in macroscopic scale [1]-[3]. Even the LHC project is important for scientific development, significantly, the fact below that is considered to bring on the point of view and considerations of the scientific community, has significance, which is not less than the significance of LHC project. The question is about arranging the apparatuses of the LHC experiment underground. Why? The objective is related with the electromagnets used in accelerating and redirecting the particles. This is caused as a result of the interaction mechanisms of irregularly deviating objects by electromagnetic waves. The effects, which are said here, may occur even if the magnitude of the field distribution is very little. The experiments like LHC should have been done at the deep of the space but not underground and

  11. Site Characterization of the Source Physics Experiment Phase II Location Using Seismic Reflection Data

    NASA Astrophysics Data System (ADS)

    Sexton, E. A.; Snelson, C. M.; Chipman, V.; Emer, D. F.; White, R. L.; Emmitt, R.; Wright, A. A.; Drellack, S.; Huckins-Gang, H.; Mercadante, J.; Floyd, M.; McGowin, C.; Cothrun, C.; Bonal, N.

    2013-12-01

    An objective of the Source Physics Experiment (SPE) is to identify low-yield nuclear explosions from a regional distance. Low-yield nuclear explosions can often be difficult to discriminate among the clutter of natural and man-made explosive events (e.g., earthquakes and mine blasts). The SPE is broken into three phases. Phase I has provided the first of the physics-based data to test the empirical models that have been used to discriminate nuclear events. The Phase I series of tests were placed within a highly fractured granite body. The evolution of the project has led to development of Phase II, to be placed within the opposite end member of geology, an alluvium environment, thereby increasing the database of waveforms to build upon in the discrimination models. Both the granite and alluvium sites have hosted nearby nuclear tests, which provide comparisons for the chemical test data. Phase III of the SPE is yet to be determined. For Phase II of the experiment, characterization of the location is required to develop the geologic/geophysical models for the execution of the experiment. Criteria for the location are alluvium thickness of approximately 170 m and a water table below 170 m; minimal fracturing would be ideal. A P-wave mini-vibroseis survey was conducted at a potential site in alluvium to map out the subsurface geology. The seismic reflection profile consisted of 168 geophone stations, spaced 5 m apart. The mini-vibe was a 7,000-lb peak-force source, starting 57.5 m off the north end of the profile and ending 57.5 m past the southern-most geophone. The length of the profile was 835 m. The source points were placed every 5 m, equally spaced between geophones to reduce clipping. The vibroseis sweep was from 20 Hz down to 180 Hz over 8 seconds, and four sweeps were stacked at each shot location. The shot gathers show high signal-to-noise ratios with clear first arrivals across the entire spread and the suggestion of some shallow reflectors. The data were

  12. Coparenting Experiences in African American Families: An Examination of Single Mothers and their Non-Marital Coparents

    PubMed Central

    Gonzalez, Michelle; Jones, Deborah J.; Parent, Justin

    2015-01-01

    African American youth from single mother homes continue to be overrepresented in statistics on risk behavior and delinquency, a trend that many be attributed to father-absence, socioeconomic disadvantage, and compromises in parenting more typical of single than two-parent families. Yet, this risk-focused perspective ignores a long-standing strength of the African American community, the involvement and potential protective impact of extended family members in childrearing. This study describes the experiences of 95 African American single mothers and their non-marital coparents who participated in a study of African American single mother families with an 11 to 16 year old child. Specifically, the study examines: 1) the extent to which nonmarital coparents are involved in childrearing; 2) the relative levels of risk (i.e., depression, mother-coparent conflict) and protective (i.e., parenting) associated with maternal and coparent involvement; and 3) how similarly and/or differently coparent and mother variables operate with regard to youth externalizing problems. Findings reveal that a range of family members and other adults actively participate in childrearing in African American single mother families, coparents do not differ from mothers on certain study variables (i.e., depression and mother-coparent conflict) but do for others (parenting), and coparent involvement is associated with youth adjustment in ways that are similar to our more established understanding of maternal involvement. The potential clinical implications of the findings are discussed and future research directions are highlighted. PMID:24479612

  13. Comparison of seismic and hydrodynamic yield determinations for the Soviet joint verification experiment of 1988.

    PubMed

    Sykes, L R; Ekström, G

    1989-05-01

    Seismic magnitudes determined from surface and body waves for the Soviet underground nuclear explosion of September 14, 1988, are used to calculate the yield of that event from previously derived calibration curves. The yield obtained by combining the two seismic estimates is 113 kilotons, which is very close to those obtained by hydrodynamic measurements made on-site. This comparison substantiates previous conclusions about the sizes of past Soviet weapons tests and compliance with the Threshold Test Ban Treaty. The factor of uncertainty in the combined seismic yield is 1.28 at the 68% and 1.62 at the 95% confidence levels, demonstrating that accuracies considerably better than a factor of 2 can be obtained by combining seismic determinations of yield.

  14. Active Source Seismic Experiment Peers Under Soufrière Hills Volcano

    NASA Astrophysics Data System (ADS)

    Voight, Barry; Sparks, R. S. J.; Hammond, J.; Shalev, E.; Malin, P.; Kenedi, C.; Minshull, T. A.; Paulatto, M.; Mattioli, G.; Hidayat, D.; Widiwijayanti, C.

    2010-07-01

    Characterizing internal structures of active volcanoes remains an enigmatic issue in geosciences. Yet studies of such structures can greatly improve hazard assessments, helping scientists to better monitor seismic signatures, geodetic deformation, and gas emissions, data that can be used to improve models and forecasts of future eruptions. Several passive seismic tomography experiments—which use travel times of seismic waves from natural earthquakes to image underground structures—have been conducted at active volcanoes (Hawaii's Kilauea, Washington's Mount St. Helens, Italy's Etna, and Japan's Unzen), but an inhomogeneous distribution of earthquakes compromises resolution. Further, if volcanic earthquakes are dominantly shallow at a given location, passive methods are limited to studying only shallow features. Thus, active source experiments—where seismic waves from the explosion of deliberately set charges are used to image below the surface—hold great potential to illuminate structures not readily seen through passive measures.

  15. Seismic passive: an experiment for the campus of the National University of Colombia

    NASA Astrophysics Data System (ADS)

    Mateus Reyes, S. E.

    2015-12-01

    The generation of seismic image, in areas where the use of active sources it is restricted (like dynamite) or just the area where the area is an active source, it is possible to do it with passive seismic, using seismic interferometry, retrieving the impulse response (Function Green) from the cross-correlation of the ambient noise. It was cross-correlated ambient seismic noise, of a recording made along a line lying on the university campus in Bogota, on that line were located the virtual-source and the traces. For processing, the surface waves were removed and subsequently, it was applied energy normalization to each of the noise panel and were correlated each noise panels with the trace at the chosen virtual-source position. When it was retrieved common-source gathers it was made a new stacking. And with this stack, seismic image was generated. The image obtained was compared with the geological surveys of the area and found that the reflectors match, showing 2 matching reflections. It was determined from this study of seismic exploration on one line, using retrieved reflection data it posible to obtain a migrated reflection imageof the subsurface.

  16. "You learn to go last": perceptions of prenatal care experiences among African-American women with limited incomes.

    PubMed

    Salm Ward, Trina C; Mazul, Mary; Ngui, Emmanuel M; Bridgewater, Farrin D; Harley, Amy E

    2013-12-01

    African American infants die at higher rates and are at greater risk of adverse birth outcomes than White infants in Milwaukee. Though self-reported experiences of racism have been linked to adverse health outcomes, limited research exists on the impact of racism on women's prenatal care experiences. The purpose of this study was to examine the experiences of racial discrimination during prenatal care from the perspectives of African American women in a low income Milwaukee neighborhood. Transcripts from six focus groups with twenty-nine women and two individual interviews were analyzed to identify important emergent themes. Validity was maintained using an audit trail, peer debriefing, and two individual member validation sessions. Participants identified three areas of perceived discrimination based on: (1) insurance or income status, (2) race, and (3) lifetime experiences of racial discrimination. Women described being treated differently by support staff and providers based on type of insurance (public versus private), including perceiving a lower quality of care at clinics that accepted public insurance. While some described personally-mediated racism, the majority of women described experiences that fit within a definition of institutionalized racism-in which the system was designed in a way that worked against their attempts to get quality prenatal care. Women also described lifetime experiences of racial discrimination. Our findings suggest that African American women with limited incomes perceive many provider practices and personal interactions during prenatal care as discriminatory. Future studies could explore the relationship between perceptions of discrimination and utilization of prenatal care.

  17. Experiments on the Brazil-nut effect due to seismic shakings

    NASA Astrophysics Data System (ADS)

    Maciel, A.; Tancredi, G.; Lluch, N.

    2014-07-01

    Size segregation processes have been identified as relevant when studying the behaviour of rocks and boulders on the surface and in the interior of a rubble-pile asteroid. The size segregation as a consequence of repeated shakings is also known as the Brazil-nut effect (BNE). These processes might be really important when studying rubble-pile -type asteroids, which may have suffered seisms as a consequence of repeated collisions; such as in the case of asteroid Itokawa. Size segregation processes can be studied using laboratory experiments as well as computational models, the first case being the one initially considered in this work. Previous studies of the BNE were performed using a sinusoidal vertical or horizontal vibration of the containers. Since we are interested in the effects of repeated seismic shakes, we have used in our experiments a sequence of repeated knocks of the container. We built a resin and polycarbonate box, which is filled with marbles of different sizes. Vacuum up to 0.5 % of ambient pressure is established inside the box. The box is subjected to repeated free-falls from heights up to 1m, with impact velocities on the ground up to 4m/s. We have chosen these low velocities since they are comparable to the escape velocities of km-size asteroids; and they are on the order of the displacement velocities of surface material as a consequence of a small impact (far from the impact point; Tancredi et al. 2012). We study the dependence of size segregation processes with the size rate among the spheres and the impact speed of the box. We observe that, when effectively occurs, size segregation mostly depends on the size rate of the particles and very little on the impact speed, even though this slight dependence has been recorded in our experiments. The laboratory experiments have been also numerically simulated using the Discrete Element Method (DEM) package known as ESyS-particle. The results of the numerical simulations are compared to the

  18. Laboratory Experiments Concerning Upwellings From the Slab-Graveyard: Implications For Geochemical and Seismic Models

    NASA Astrophysics Data System (ADS)

    Harris, A. C.; Kincaid, C.; Hall, P.

    2005-12-01

    The ongoing plume debate appears to focus on upwellings characterized by large heads and smaller tails, that form from a deep or basal thermal boundary layer (BTBL), which are driven by temperature excesses in the range of 200° C. We use 3-D laboratory experiments to explore how upwellings might differ from this common plume description when BTBLs are influenced by subducted plates. An important aspect of the models is the representation of ridge chemical differentiation processes resulting in slabs with two distinct layers; a lighter, depleted upper mantle component (Harzburgite:H) and a heavier, iron-rich crustal component (Basalt/Eclogite:B/E). Laboratory experiments utilize a working fluid of glucose syrup with temperature dependent density and viscosity. Compositionally distinct mantle reservoirs are represented through isothermal density/viscosity contrasts controlled by water content. The ambient fluid (AF) is contained within a rectangular tank that is heated from below and cooled from above to produce background convection with a Rayleigh number of 10-5-10-6. Highly viscous, tabular slabs are produced by pouring compositionally distinct syrup from two slab reservoirs (B/E and H) into a mold which is chilled to -5° C. The viscous layered slab is emplaced at the fluid surface and subsequently sinks through, stalls and spreads within a BTBL roughly twice the slab thickness (1 cm). Results show that a wide variety in upwelling morphologies form when layered slabs reside within the BTBL and that plume heads/tails are largely dissimilar to those of the standard plume model. The manner in which the slab laminae vs. AF in the BTBL combine (or segregate) within upwellings depends on viscosity/density contrasts, how slabs collapse in the BTBL, and time. End-member regimes include: experiments dominated by a very light H-slab component with early, cold H-plumes and late, hot B/E-AF plumes and experiments where density differences between H, B/E and AF are small and

  19. Jumping through Hoops: College Choice Experiences of African American Male Community College Club Basketball Players

    ERIC Educational Resources Information Center

    Ellis, Kimberly Carlotta

    2011-01-01

    This study aimed to learn what factors influenced the college choice decision-making process of African American male club basketball players in the community college. To understand how the participants determined their educational path, face-to-face interviews were conducted with 21 African American male students who were enrolled in at least six…

  20. Teaching White Students Black History: The African-American Experience in the Classroom

    ERIC Educational Resources Information Center

    Burrell, Leon F.; Walsh, Robert L.

    2001-01-01

    Many white students are barely exposed to African-American history throughout their schooling. When students do examine the other side of American history, the one not generally found in their textbooks, they often wonder why they have not learned this before. An understanding of African-American history is central to any effort to eliminate…

  1. Gender and Racial Experiences in Executive School Leadership: Perceptions of African American Female Superintendents

    ERIC Educational Resources Information Center

    Colbert, Daveda Jean

    2009-01-01

    There is a leadership crisis that exists in our schools creating an urgent need for effective leadership. Even though African American women have made slight gains, throughout the country people of color and women are dramatically underrepresented in the superintendency. Therefore, the primary purpose of this study is to provide African American…

  2. Experiences of High School Teachers and Administrators Regarding Suspension of African American Males

    ERIC Educational Resources Information Center

    Robinson, Corwin

    2014-01-01

    The large number of suspensions of African American high school males is one of the primary concerns facing high school administrators nationwide. At high schools in the southern United States, African American males are suspended at greater rates than their counterparts. Suspensions affect their levels of achievement, attitudes towards school,…

  3. In Their Own Words: African American Women Narrate Their Experiences to Leadership

    ERIC Educational Resources Information Center

    Choates, Ramelli

    2012-01-01

    This study employs a qualitative approach, using oral narratives to provide the life stories of five African American women administrators in higher education. The purpose of the study is to understand the impact of various influences, sources of support, and impact of mentorship on African American women who obtained senior administrative…

  4. When Aspiration Meets Opportunity: Examining Transitional Experiences of African American Males in College Readiness Programs

    ERIC Educational Resources Information Center

    Baber, Lorenzo DuBois

    2014-01-01

    The lack of postsecondary success for African American males has garnered significant attention from academic scholars and public policy leaders. While this scholarship provides a strong portrait on issues related to African American males, there are still significant gaps to be addressed. Most notably, current research tends to focus on students…

  5. Reflections on Academic Development: What We Can Learn from the South African Experience. Technical Report.

    ERIC Educational Resources Information Center

    Epstein, Ruth

    A study examined academic literacy in high-risk South African students entering postsecondary education, and the relationship of academic literacy to instructional development. Data were gathered in discussions with academic staff at South African universities and technikons and at the University of Saskatchewan. The report begins with background…

  6. Health Behaviors and Breast Cancer: Experiences of Urban African American Women

    ERIC Educational Resources Information Center

    Stolley, Melinda R.; Sharp, Lisa K.; Wells, Anita M.; Simon, Nolanna; Schiffer, Linda

    2006-01-01

    Breast-cancer survival rates are lower among African American women compared to White women. Obesity may contribute to this disparity. More than 77% of African American women are overweight or obese. Adopting health behaviors that promote a healthy weight status may be beneficial because obesity increases risk for recurrence. Studies among White…

  7. High-resolution shallow-seismic experiments in sand. Part 1: Water table, fluid flow, and saturation

    SciTech Connect

    Bachrach, R.; Nur, A.

    1998-07-01

    A high-resolution, very shallow seismic reflection and refraction experiment was conducted to investigate the seismic response of groundwater level changes in beach sand in situ. A fixed 10-m-long receiver array was used for repeated seismic profiling. Direct measurements of water level in a monitoring well and moisture content in the sand were taken as well. The water table in the well changed by about 1 m in slightly delayed response to the nearby ocean tides. In contrast, inversion of the seismic data yielded a totally different picture. The reflection from the water table at high tide appeared at a later time than the reflection at low tide. This unexpected discrepancy can be reconciled using Gassmann`s equation: a low-velocity layer must exist between the near-surface dry sand and the deeper and much faster fully saturated sand. This low-velocity layer coincides with the newly saturated zone and is caused by a combination of the sand`s high density (close to that of fully saturated sand), and its high compressibility (close to that of dry sand). This low-velocity zone causes a velocity pull-down for the high-frequency reflections, and causes a high-tide reflection to appear later in time than low-tide reflection. The calculated velocities in the dry layer show changes with time that correlate with sand dryness, as predicted by the temporal changes of the sand`s density due to changing water/air ratio. The results show that near-surface velocities in sand are sensitive to partial saturation in the transition zone between dry and saturated sand. The authors were able to extract the saturation of the first layer and the depth to the water table from the seismic velocities.

  8. Anatomy of a Metamorphic Core Complex: Preliminary Results of Ruby Mountains Seismic Experiment, Northeastern Nevada

    NASA Astrophysics Data System (ADS)

    Schiltz, K. K.; Litherland, M.; Klemperer, S. L.

    2010-12-01

    The Ruby Mountains Seismic Experiment is a 50-station deployment of Earthscope’s Flexible Array installed in June 2010 to study the Ruby Mountain metamorphic core complex, northeastern Nevada. Competing theories of metamorphic core complexes stress the importance of either (1) low-angle detachment faulting and lateral crustal flow, likely leading to horizontal shearing and anisotropy, or (2) vertical diapirism creating dominantly vertical shearing and anisotropy. Our experiment aims to distinguish between these two hypotheses using densely spaced (5 to 10 km) broadband seismometers along two WNW-ESE transects across the Ruby Range and one NNE-SSW transect along the axis of the range. When data acquisition is complete we will image crustal structures and measure velocity and anisotropy with a range of receiver function, shear-wave splitting and surface-wave tomographic methods. In addition to the newly acquired data, existing data can also be used to build understanding of the region. Previous regional studies have interpreted shear-wave splitting in terms of single-layer anisotropy in the mantle, related to a complex flow structure, but previous controlled source studies have identified measurable crustal anisotropy. We therefore attempted to fit existing data to a two-layer model consisting of a weakly anisotropic crustal layer and a more dominant mantle layer. We used “SplitLab” to measure apparent splitting parameters from ELK (a USGS permanent station) and 3 Earthscope Transportable Array stations. There is a clear variation in the splitting parameters with back-azimuth, but existing data do not provide a stable inversion for a two-layer model. Our best forward-model solution is a crustal layer with a fast axis orientation of 357° and 0.3 second delay time and a mantle layer with a 282° fast axis and 1.3 s delay time. Though the direction of the fast axis is consistent with previously published regional results, the 1.3 s delay time is larger than

  9. SinoProbe seismic experiment in Tibetan plateau (2008-2012)

    NASA Astrophysics Data System (ADS)

    Gao, R.; Sinoprobe-02 Tibetan Team

    2010-12-01

    SinoProbe Project is a five-year (2008-2012) Chinese National Special Project to use exploration geophysical methods to image the deep structure of continental China. The Tibetan Plateau is one of the most important probing areas including three main profiles: A, B, C, and two accessory profiles: D and E. Three main seismic methods, deep reflection profile (CMP), deep seismic sounding (DSS) and broad band (BB) survey, will be used in profiles: A, B, C, and D, in profile E only broad band survey will be done. Profile A is located in northeastern margin of Tibetan Plateau, covering the Zoigê basin, West Qinling Mt., Linxia Basin, Qilian Mt., and ends at Ala Shan block. Recently, we completed a total length of ~600 km deep seismic reflection and refraction profile. Broad band survey along the profile will be done in 2011. Location of Profile D is across the Longmenshan Mts. Because there are still strong seismic activities in this area, deep seismic reflection survey has been put off to 2012. Profile B is across Bangong-Nujiang Suture and Qiangtang terrane. Recently, we completed a total length of ~300 km deep seismic reflection profile. Broad band survey is being carried on, and refraction profile will be done in 2011. Profile E is a “Y” shape broad band survey, extending to the north across Qaidam basin and Altyn Mts., its field work is also carried on and will be finished late this year. Profile C is located in western Himalayan Mts. and across Karakoram fault and Nujiang Suture. Total length is about 200 km for seismic reflection, 300-400 km for seismic refraction and broad band survey. This work will be done in late 2010 or early 2011. We welcome other scientists to join us, to collaborate on acquisition and processing of deep seismic data in Tibetan plateau. Through joint research to create an environment for integrated understanding the geodynamics of the Tibetan plateau. We hope to develop a long-term, mutually beneficial partnership through our

  10. Exploring How African American Males from an Urban Community Navigate the Interracial and Intra-Racial Dimensions of Their Experiences at an Urban Jesuit High School

    ERIC Educational Resources Information Center

    Simmons, Robert W., III

    2012-01-01

    African American males from urban communities have been attending Jesuit high schools in urban spaces for many years, yet little to no literature exists that explores their experiences while attending these elite private schools. This qualitative study of 10 African American males from an urban community attending a similarly positioned Jesuit…

  11. A Hermeneutic Phenomenological Study of the Experiences of Female African American Undergraduate Engineering Students at a Predominantly White and an Historically Black Institution

    ERIC Educational Resources Information Center

    Frillman, Sharron Ann

    2011-01-01

    This phenomenological study examined the experiences of twelve female African Americans enrolled as fulltime undergraduate engineering students at North Carolina Agricultural and Technical State University, an historically Black university, and seven female African Americans enrolled as undergraduate engineering students at Purdue University in…

  12. Navigating Race and Cultural Identity: A Phenomenological Study of the Lived Experiences of African American Secondary Principals on the U.S.-Mexico Border of El Paso, Texas

    ERIC Educational Resources Information Center

    Hill, Natashia J.

    2013-01-01

    Presently the paucity of scholarship available is often unitary in nature and usually focuses on the lived experiences of African Americans principals in a predominately African American urban context and as well as emphasizes the necessity of same race principals for the purpose of mentorship and racial representation. Race and cultural identity…

  13. "Ain't Nobody Gonna Get Me down": An Examination of the Educational Experiences of Four African American Women Labeled with Disabilities

    ERIC Educational Resources Information Center

    Petersen, Amy J.

    2009-01-01

    This study used qualitative research methods to explore the educational experiences of four African American women with disabilities, revealing how each participant developed a critical consciousness in response to the dominant ideology surrounding the discourses of African American, woman, and disabled. The development of a critical consciousness…

  14. Experimenting in Distance Education: The African Virtual University (AVU) and the Paradox of the World Bank in Kenya--A Rejoinder

    ERIC Educational Resources Information Center

    Munene, Ishmael I.

    2007-01-01

    This rejoinder is in response to criticism against the African Virtual University (AVU), an internet-based education modality, by Amutabi and Oketch [2003. Experimenting in distance education: the African Virtual University (AVU) and the Paradox of World Bank in Kenya. International Journal of Educational Development 23, 57-73]. By closely…

  15. Fault rupture as a series of nano-seismic events during high-velocity shear experiments

    NASA Astrophysics Data System (ADS)

    Zu, X.; Reches, Z.; Chen, X.; Chang, J. C.; Carpenter, B. M.

    2015-12-01

    The rupture process of experimental faults is investigated here by monitoring nano-seismic events (NSE) during slip in a rotary shear apparatus. Our experimental faults are made of two rock blocks with one to four miniature 3D accelerometers that are glued to the stationary block at distance of ~ 2 cm from the fault surface. Accelerations in the frequency range of 1 Hz to 200 kHz are recorded in slip-parallel (x), slip-transverse (y), and slip-vertical (z) directions. We conducted a series of 45 experiments on diorite and dolomite samples in two loading styles: classical velocity controlled loading, and power-density loading, in which the power-density (shear stress times slip velocity) is selected, and stick-slip events develop spontaneously according to the experimental fault response. The 3D accelerometer data were recorded at 106 samples/s, with acceleration resolution of 10 mV/g in recoding range of +/- 5 V. The experiments were conducted at slip-velocity of 0.001-0.8 m/s and slip distance up to 1.38 m. The accelerometer observations revealed tens to hundreds of NSEs per slip in both loading styles; peak acceleration ranged from 1g to over 500g. A typical stick-slip with tens of NSEs in Fig. 1, shows: (1) An initial NSE at ~59.72 s (green) that coincides with a small stress drop (~10%, red); (2) Simultaneous macroscopic slip initiation (blue); (3) A swarm of NSEs occur as the fault slips, each NSE lasts 1-2 milliseconds; and (4) Details of the initial NSE are shown in Fig. 2. Based on waveform cross-correlation between frequency band from 20 kHz to 70kHz, we identify several groups of NSE clusters, and apply empirical Green's function method to analyze event source spectra based on Brune-type source model. These NSEs are indicators of rupture propagation during the experimental fault slip.

  16. Modeling Wide-Angle Seismic Data from the Hi-CLIMB Experiment in Tibet

    NASA Astrophysics Data System (ADS)

    Nowack, R. L.; Griffin, J. D.; Tseng, T.; Chen, W.

    2009-12-01

    Using data from local and regional events recorded by the Hi-CLIMB array in Tibet, we utilize seismic attributes, including arrival times, Hilbert amplitudes and pulse frequencies, to constrain structures of seismic wave speed and attenuation in the crust and the upper mantle in western China. We construct more than 30 high-quality, regional seismic profiles, and select 14 of these, which show excellent crustal and Pn arrivals, for further analysis. Travel-times from events at regional distances constrain large-scale velocity structures, and four close-in events provide further details on crustal structure. We use the 3-D ray tracer, CRT, to model the travel-times. Initial results indicate that the Moho beneath the Lhasa terrane of southern Tibet is over 73 km deep with a high Pn speed of about 8.2 km/s. In contrast, the Qiangtang terrane farther north shows a thinner crust, by up to 10 km, and a low Pn speed of 7.8-7.9 km/s. Preliminary estimates of upper mantle velocity gradients are between .003 and .004 km/s per km, consistent with previous results by Phillips et al. (2007). We also use P to SV conversions from teleseismic earthquakes to independently constrain variations in speeds of Pn and depths of the Moho. For instance, amplitudes of the SsPmP phase, when its last reflection off the Moho is near-critical, are particularly sensitive to the contrast in seismic wave speeds across the crust-mantle interface; and results from these additional data are consistent with those from modeling of travel-times. Additional seismic attributes, extracted from wave-trains containing Pn and major crustal phases, are being compared with results of numerical modeling based on the spectral element method and asymptotic calculations in laterally varying media, where both lateral and vertical gradients in seismic wave speeds can strongly affect Pn amplitudes and pulse frequencies.

  17. Planning the improvement of seismic monitoring in a volcanic supersite: experience on Mt. Etna

    NASA Astrophysics Data System (ADS)

    D'Alessandro, Antonino; Scarfi, Luciano; Scaltrito, Antonio; Aiesi, Giampiero; Di Prima, Sergio; Ferrari, Ferruccio; Rapisarda, Salvatore

    2013-04-01

    Etna is one of the most active volcanoes in the world and one of the most intriguing natural laboratories for the understanding of eruptive processes and lava uprising in basalt-type volcanic environments; indeed, it is considered, by the scientific international community, together with the Vesuvius and the Hawaiian Islands, as a volcanic supersite. Its activity is continuously monitored by the Osservatorio Etneo of the Istituto Nazionale di Geofisica e Vulcanologia (INGV), by means of an array of integrated multidisciplinary techniques. In particular, Etna seismicity is recorded by a dense local seismic network (ESN- Etna Seismic Network), which, nowadays, consists of about 40 real-time seismic stations, many of which equipped with broadband velocity and accelerometer sensors. The data are analyzed routinely in detail by the Osservatorio Etneo staff, producing daily and periodic reports and bulletins of the earthquakes located in the whole Sicily and southern Calabria region. In the last decades, seismological observations provided important information on both the dynamics and internal structure of the volcano, in addition to their interaction with the regional tectonic structures. In the last year, in the framework of the VULCAMED project, an INGV workgroup has taken on the task of developing the existing seismic network through the installation of new measurement stations. By considering the spatial distribution of earthquakes in the area, the presence of structures known as seismically active and through extensive geological-geophysical surveys, ten potential new sites were identified. In the following months, some of these sites will complement the existing network. The choice of optimal sites must clearly be made through a careful analysis of environmental noise, of the possible logistics, technical and broadcast problems, but must also take into account the geometry of the existing seismic network. For this purpose, we applied the Seismic Network

  18. U. S. Geological Survey begins seismic ground response experiments in Washington State

    USGS Publications Warehouse

    Tarr, A.C.; King, K.W.

    1987-01-01

    The men were Denver-based U.S Geological Survey (USGS) geophysicists working on the Urban Hazards Field Investigations project. On the previous day they had recorded two events on their seismographs-a distant nuclear explosion in Nevada and a blast at amine near Centralia, Washington. On another day, they used seismic refraction equipment to locate the depth of bedrock and seismic velocity to it at several locations in West Seattle and in the Seward Park-Brighton district of southeast Seattle. 

  19. Ghana's experience in the establishment of a national digital seismic network observatory

    NASA Astrophysics Data System (ADS)

    Ahulu, Sylvanus; Danuor, Sylvester Kojo

    2015-07-01

    The Government of Ghana has established a National Digital Seismic Network Observatory in Ghana with the aim of monitoring events such as earthquakes, blasts from mining and quarrying, nuclear tests, etc. The Digital Observatory was commissioned on 19 December 2012, and was dedicated to Geosciences in Ghana. Previously Ghana did not have any operational, digital seismic network acquisition system with the capability of monitoring and analysing data for planning and research purposes. The Ghana Geological Survey has been monitoring seismic events with an analogue system which was not efficient and does not deliver real-time data. Hence, the importance of setting up the National Digital Seismic Network System which would enable the Geological Survey to constantly monitor, manage and coordinate both natural and man-made seismic activities in the country and around the globe, to some extent on real-time basis. The Network System is made up of six remote digital stations that transmit data via satellite to the central observatory. Sensors used are 3× Trillium Compact and 3× Trillium 120PA with Trident digitizers. The department has also acquired strong motion equipment: Titan accelerometers with Taurus digitizers from Nanometrics. Three of each of these instruments have been installed at the Akosombo and Kpong hydrodams, and also at the Weija water supply dam. These instruments are used to monitor dams. The peak ground acceleration (PGA) values established from the analysed data from the accelerometers will be used to retrofit or carry out maintenance work of the dam structures to avoid collapse. Apart from these, the observatory also assesses and analyses seismic waveforms relevant to its needs from the Global Seismographic Network (GSN) system operated by the US Geological Survey. The Ghana Geological Survey, through its Seismic Network Observatory makes data available to its stakeholder institutions for earthquake disaster mitigation; reports on all aspects of

  20. Experiences of African immigrant women living with HIV in the U.K.: implications for health professionals.

    PubMed

    Ndirangu, Eunice W; Evans, Catrin

    2009-04-01

    In the U.K. immigrant women from Africa constitute an increasingly large proportion of newly diagnosed cases of HIV. A significant minority of these are refugees and asylum seekers. Very little is known about their experiences of living with HIV/AIDS, their psychosocial needs or their views of health care provision. This paper reports the results of a qualitative study that explored these issues by interviewing eight African women living with HIV in the British city of Nottingham. Women's ability to live positively with HIV was found to be strongly shaped by their migration history, their legal status, their experience of AIDS-related stigma and their Christian faith. Significantly, health services were represented as a safe social space, and were highly valued as a source of advice and support. The findings indicate that non-judgemental, personalised health care plays a key role in encouraging migrant African women to access psychosocial support and appropriate HIV services.

  1. Health Care Experiences and Perceived Barriers to Health Care Access: A Qualitative Study Among African Migrants in Guangzhou, Guangdong Province, China

    PubMed Central

    Brown, Katherine B.; Yu, Fan; Yang, Jingqi; Wang, Jason; Schrock, Joshua M.; Bodomo, Adams B.; Yang, Ligang; Yang, Bin; Nehl, Eric J.; Tucker, Joseph D.; Wong, Frank Y.

    2014-01-01

    Guangzhou, one of China's largest cities and a main trading port in South China, has attracted many African businessmen and traders migrating to the city for financial gains. Previous research has explored the cultural and economic roles of this newly emerging population; however, little is known about their health care experiences while in China. Semi-structured interviews and focus groups were used to assess health care experiences and perceived barriers to health care access among African migrants in Guangzhou, China. Overall, African migrants experienced various barriers to accessing health care and were dissatisfied with local health services. The principal barriers to care reported included affordability, legal issues, language barriers, and cultural differences. Facing multiple barriers, African migrants have limited access to care in Guangzhou. Local health settings are not accustomed to the African migrant population, suggesting that providing linguistically and culturally appropriate services may improve access to care for the migrants. PMID:25294415

  2. Modelling Active Faults in Probabilistic Seismic Hazard Analysis (PSHA) with OpenQuake: Definition, Design and Experience

    NASA Astrophysics Data System (ADS)

    Weatherill, Graeme; Garcia, Julio; Poggi, Valerio; Chen, Yen-Shin; Pagani, Marco

    2016-04-01

    The Global Earthquake Model (GEM) has, since its inception in 2009, made many contributions to the practice of seismic hazard modeling in different regions of the globe. The OpenQuake-engine (hereafter referred to simply as OpenQuake), GEM's open-source software for calculation of earthquake hazard and risk, has found application in many countries, spanning a diversity of tectonic environments. GEM itself has produced a database of national and regional seismic hazard models, harmonizing into OpenQuake's own definition the varied seismogenic sources found therein. The characterization of active faults in probabilistic seismic hazard analysis (PSHA) is at the centre of this process, motivating many of the developments in OpenQuake and presenting hazard modellers with the challenge of reconciling seismological, geological and geodetic information for the different regions of the world. Faced with these challenges, and from the experience gained in the process of harmonizing existing models of seismic hazard, four critical issues are addressed. The challenge GEM has faced in the development of software is how to define a representation of an active fault (both in terms of geometry and earthquake behaviour) that is sufficiently flexible to adapt to different tectonic conditions and levels of data completeness. By exploring the different fault typologies supported by OpenQuake we illustrate how seismic hazard calculations can, and do, take into account complexities such as geometrical irregularity of faults in the prediction of ground motion, highlighting some of the potential pitfalls and inconsistencies that can arise. This exploration leads to the second main challenge in active fault modeling, what elements of the fault source model impact most upon the hazard at a site, and when does this matter? Through a series of sensitivity studies we show how different configurations of fault geometry, and the corresponding characterisation of near-fault phenomena (including

  3. Improving detection and identification of seismic signals due to landslides: a methodology based on field scale controlled experiments

    NASA Astrophysics Data System (ADS)

    Yfantis, G.; Carvajal, H. E.; Pytharouli, S.; Lunn, R. J.

    2013-12-01

    A number of published studies use seismic sensors to understand the physics involved in slope deformation. In this research we artificially induce failure to two meter scaled slopes in the field and use 12 short period 3D seismometers to monitor the failure. To our knowledge there has been no previous controlled experiments that can allow calibration and validation of the interpreted seismic signals. Inside the body of one of the artificial landslides we embed a pile of glass shards. During movement the pile deforms emitting seismic signals due to friction among the glass shards. Our aim is twofold: First we investigate whether the seismic sensors can record pre-cursory and failure signals. Secondly, we test our hypothesis that the glass shards produce seismic signals with higher amplitudes and a distinct frequency pattern, compared to those emitted by common landslide seismicity and local background noise. Two vertical faces, 2m high, were excavated 3m apart in high porous tropical clay. This highly attenuating material makes the detection of weak seismic signals challenging. Slope failure was induced by increasing the vertical load at the landslide's crown. Special care was taken in the design of all experimental procedures to not add to the area's seismic noise. Measurements took place during 18 hours (during afternoon and night) without any change in soil and weather conditions. The 3D sensors were placed on the ground surface close to the crown, forming a dense microseismic network with 5-to-10m spacing and two nanoseismic arrays, with aperture sizes of 10 and 20 m. This design allowed a direct comparison of the recorded signals emitted by the two landslides. The two faces failed for loading between 70 and 100kN and as a result the pile of glass shards was horizontally deformed allowing differential movement between the shards. After the main failure both landslides were continuing to deform due to soil compaction and horizontal displacement. We apply signal

  4. Passive, broad-band seismic measurements for geothermal exploration : The GAPSS experiment

    NASA Astrophysics Data System (ADS)

    Saccorotti, Gilberto; Piccinini, Davide; Zupo, Maria; Mazzarini, Francesco; Cauchie, Lena; Chiarabba, Claudio; Piana Agostinetti, Nicola

    2014-05-01

    Passive seismological imaging techniques based on either transient (earthquakes) or sustained (background noise) signals can provide detailed descriptions of subsurface attributes as seismic velocity, attenuation, and anisotropy. However, the correspondence between these parameters and the physical properties of crustal fluids is still ambiguous. Moreover, the resolving capabilities and condition of applicability of emerging techniques such as the Ambient Noise Tomography are still to be investigated thoroughly. Following these arguments, a specific project (GAPSS-Geothermal Area Passive Seismic Sources) was planned, in order to test passive exploration methods on a well-known geothermal area, namely the Larderello-Travale Geothermal Field (LTGF). This geothermal area is located in the western part of Tuscany (Italy), and it is the most ancient geothermal power field of the world. Heat flow in this area can reach local peaks of 1000 mW/m3. The deep explorations in this area showed a deeper reservoir (3000 to 4000 m depth) located within the metamorphic rocks in the contact aureole of the Pliocene-Quaternary granites; it is characterized by a wide negative gravimetric anomaly, interpreted as partially molten granite at temperatures of 800°C. From seismic surveys the K-marker K (pressurized horizons) was found at depths between 3 and 7 km. The structural grain of the geothermal field is characterized by N-W trending and N-E dipping normal faults whose activity lasts since the Pliocene. GAPSS lasted from early May, 2012, through October, 2013. It consisted of up to 20 temporary seismic stations, complemented by two permanent stations from the National Seismic Network of Italy. The resulting array has an aperture of about 50 Km, with station spacings between 2 and 50 km. Stations are equipped with either broadband (40s and 120s) or intermediate-period (5s), 3-components seismometers. LTGF is seismically active. During the first 10 months of measurements, we located

  5. Factors linking childhood experiences to adult romantic relationships among African Americans.

    PubMed

    Simons, Leslie Gordon; Simons, Ronald L; Landor, Antoinette M; Bryant, Chalandra M; Beach, Steven R H

    2014-06-01

    It is well known that a high-quality relationship with a romantic partner is related to a variety of positive outcomes associated with health and well-being. Establishing such relationships is an important developmental task for young adults, and past research indicates that there is a link between experiences in the family of origin and the success of later intimate relationships. It has been suggested that this association can be explained by the acquisition of social competencies (e.g., emotions, schemas, traits) that are acquired during childhood in the family of origin and, in turn, influence interaction with adult romantic partners. The current study builds on this foundation by identifying particular competencies expected to explain the association between childhood exposure to supportive and harsh parenting and later patterns of interaction with romantic partners. Specifically, we examine anger management, attachment style, hostile attribution bias, and self-control as potential mediators using prospective, longitudinal data from a sample of 345 African American young adults. Results from structural equation modeling indicate that each of the mediators in our study accounts for a significant portion of the effect of parenting on the quality of adult romantic relationships, although the constructs linking parenting to warm interactions with romantic partners are somewhat different from those that link parenting to hostile interactions with romantic partners. Even after accounting for the effect of the mediators, there is still a direct effect of parenting on both warm/loving and hostile/aggressive interactions with romantic partner. Implications for theory and practice are discussed. PMID:24730381

  6. Factors linking childhood experiences to adult romantic relationships among African Americans.

    PubMed

    Simons, Leslie Gordon; Simons, Ronald L; Landor, Antoinette M; Bryant, Chalandra M; Beach, Steven R H

    2014-06-01

    It is well known that a high-quality relationship with a romantic partner is related to a variety of positive outcomes associated with health and well-being. Establishing such relationships is an important developmental task for young adults, and past research indicates that there is a link between experiences in the family of origin and the success of later intimate relationships. It has been suggested that this association can be explained by the acquisition of social competencies (e.g., emotions, schemas, traits) that are acquired during childhood in the family of origin and, in turn, influence interaction with adult romantic partners. The current study builds on this foundation by identifying particular competencies expected to explain the association between childhood exposure to supportive and harsh parenting and later patterns of interaction with romantic partners. Specifically, we examine anger management, attachment style, hostile attribution bias, and self-control as potential mediators using prospective, longitudinal data from a sample of 345 African American young adults. Results from structural equation modeling indicate that each of the mediators in our study accounts for a significant portion of the effect of parenting on the quality of adult romantic relationships, although the constructs linking parenting to warm interactions with romantic partners are somewhat different from those that link parenting to hostile interactions with romantic partners. Even after accounting for the effect of the mediators, there is still a direct effect of parenting on both warm/loving and hostile/aggressive interactions with romantic partner. Implications for theory and practice are discussed.

  7. Time-frequency-wavenumber Decomposition To Investigate Seismic Wavefield: Application To The Annot Experiment

    NASA Astrophysics Data System (ADS)

    Schissele, E.; Cansi, Y.; Gaffet, S.

    Many observations and studies as well as numerical simulations have been done in order to completely understand the whole seismogram recorded during an earthquake. At regional distances, the seismic wavefield is strongly influenced by crustal hetero- geneities. The primary wavefield constituted by Pn, Pg, Sn, Sg, Rg, Lg.... phases is diffracted and refracted by these heterogeneities and hence forms the coda of the seis- mogram. But the different mechanisms of propagation in a heterogeneous medium are not fully understood. The identification of the different phases contributing to the coda seems to be essential to progress in the comprehension of the seismic wavefield propagation. Seismic arrays are then well-adapted tools since they provide the spatio-temporal evo- lution of the wavefield. In 1998, 4 small-scales arrays were deployed for 2 months around the Annot region, located in the southern French Alps. Each array was constituted by 9 short-period seismometers, recording frequencies greater than 0.2 Hz. Its aperture was 250 meters, with a minimal distance between 2 adjacent sensors of 20 meters. That allows us to study the seismic wavefield for very low wavelength without any problem of spatial aliasing. It will be interesting to characterize in terms of wavefield deformation the signature of the different kinds of heterogeneities (fault system, topographic relief, impedance contrast...) surrounding this area. We expect the primary wavefield to be diffracted or refracted by all these heterogeneities. A time-frequency-wavenumber technique which allows us to characterize the whole coherent part of the energy which prop- agates through the seismic array has been derived. Such a characterization involves, for each coherent wavelet, an estimate of: (i) an arrival time and a frequency content and (ii) an azimuth and an apparent velocity. This way, the principal phases will be described. What will be more interesting, is the extraction of the deterministic part of the

  8. Rocky Mountain evolution: Tying Continental Dynamics of the Rocky Mountains and Deep Probe seismic experiments with receiver functions

    USGS Publications Warehouse

    Rumpfhuber, E.-M.; Keller, Gordon R.; Sandvol, E.; Velasco, A.A.; Wilson, D.C.

    2009-01-01

    In this study, we have determined the crustal structure using three different receiver function methods using data collected from the northern transect of the Continental Dynamics of the Rocky Mountains (CD-ROM) experiment. The resulting migrated image and crustal thickness determinations confirm and refine prior crustal thickness measurements based on the CD-ROM and Deep Probe experiment data sets. The new results show a very distinct and thick lower crustal layer beneath the Archean Wyoming province. In addition, we are able to show its termination at 42??N latitude, which provides a seismic tie between the CD-ROM and Deep Probe seismic experiments and thus completes a continuous north-south transect extending from New Mexico into Alberta, Canada. This new tie is particularly important because it occurs close to a major tectonic boundary, the Cheyenne belt, between an Archean craton and a Proterozoic terrane. We used two different stacking techniques, based on a similar concept but using two different ways to estimate uncertainties. Furthermore, we used receiver function migration and common conversion point (CCP) stacking techniques. The combined interpretation of all our results shows (1) crustal thinning in southern Wyoming, (2) strong northward crustal thickening beginning in central Wyoming, (3) the presence of an unusually thick and high-velocity lower crust beneath the Wyoming province, and (4) the abrupt termination of this lower crustal layer north of the Cheyenne belt at 42??N latitude. Copyright 2009 by the American Geophysical Union.

  9. Experiences and perspectives of African American, Latina/o, Asian American, and European American psychology graduate students: A national study.

    PubMed

    Maton, Kenneth I; Wimms, Harriette E; Grant, Sheila K; Wittig, Michele A; Rogers, Margaret R; Vasquez, Melba J T

    2011-01-01

    A national, Web-based survey of 1,219 African American, Latina/o, Asian American, and European American psychology graduate students revealed both similarities and differences in experiences and perspectives. Mentoring was found to be the strongest predictor of satisfaction across groups. Academic supports and barriers, along with perceptions of diversity within the academic environment, were also important predictors of satisfaction. Students of color perceived less fairness of representation of their ethnic group within psychology than European American students, and a greater linkage between aspects of the graduate school experience and their ethnicity. Limitations of the study and implications for future research and action are discussed.

  10. African American Women’s Limited Knowledge and Experiences with Genetic Counseling for Hereditary Breast Cancer

    PubMed Central

    Sheppard, Vanessa B.; Graves, Kristi D.; Christopher, Juleen; Hurtado-de-Mendoza, Alejandra; Talley, Costellia; Williams, Karen Patricia

    2014-01-01

    Genetic counseling and testing for hereditary breast cancer have the potential benefit of early detection and early interventions in African American women. However, African American women have low use of these services compared to White women. We conducted two focus groups with African American women diagnosed with breast cancer (affected group, n=13) and women with at least one first-degree relative with breast/ovarian cancer (unaffected group, n= 8). A content analysis approach was employed to analyze interview data. Breast cancer survivors had more knowledge about genetic counseling and testing than participants who were unaffected with cancer. However, knowledge about genetic counseling was limited in both groups. Barriers to pursuing genetic counseling and testing included poor understanding of the genetic counseling and testing process, fear of carrying the mutation, concerns about discrimination, and cost. Motivators to participate in genetic counseling and testing included desire to help family members, insurance coverage, and potential of benefiting the larger African American community. Education efforts are needed to increase genetic counseling and testing awareness in the African American community. PMID:24186304

  11. African American women's limited knowledge and experiences with genetic counseling for hereditary breast cancer.

    PubMed

    Sheppard, Vanessa B; Graves, Kristi D; Christopher, Juleen; Hurtado-de-Mendoza, Alejandra; Talley, Costellia; Williams, Karen Patricia

    2014-06-01

    Genetic counseling and testing for hereditary breast cancer have the potential benefit of early detection and early interventions in African American women. However, African American women have low use of these services compared to White women. We conducted two focus groups with African American women diagnosed with breast cancer (affected group, n = 13) and women with at least one first-degree relative with breast/ovarian cancer (unaffected group, n = 8). A content analysis approach was employed to analyze interview data. Breast cancer survivors had more knowledge about genetic counseling and testing than participants who were unaffected with cancer. However, knowledge about genetic counseling was limited in both groups. Barriers to pursuing genetic counseling and testing included poor understanding of the genetic counseling and testing process, fear of carrying the mutation, concerns about discrimination, and cost. Motivators to participate in genetic counseling and testing included desire to help family members, insurance coverage, and potential of benefiting the larger African American community. Education efforts are needed to increase genetic counseling and testing awareness in the African American community.

  12. Theory and experiment of an inertia-type vertical isolation system for seismic protection of equipment

    NASA Astrophysics Data System (ADS)

    Lu, Lyan-Ywan; Chen, Pei-Rong; Pong, Kuan-Wen

    2016-03-01

    Although it has been proven that seismic isolation is an effective technology for seismic protection of structures and equipment, most existing isolation systems are for mitigating horizontal ground motions, and in practice there are very few vertical isolation systems. Part of the reason is due to the conflict with regard to the demand for isolation stiffness. In other words, a vertical isolation system must have sufficient vertical rigidity to sustain the weight of the isolated object, while it must also have sufficient flexibility in order to elongate the vibration period under seismic excitation. In order to overcome this difficulty, a novel system is proposed in this study, called an inertia-type vertical isolation system (IVIS). The primary difference between the IVIS and a traditional system is that the former has an additional leverage mechanism with a counterweight. The counterweight will provide a static uplifting force and an extra dynamic inertia force, such that the effective vertical stiffness of the IVIS becomes higher in its static state and lower in the dynamic one. The theory underlying the IVIS is developed and verified experimentally by a seismic simulation test in this work. The results show that the IVIS leads to a less static settlement and at the same time a lower effective isolation frequency. The test results also demonstrate that the isolator displacement demand of the IVIS is only about 30-40 percent that of the traditional one in all kinds of earthquakes. With regard to the reduction of acceleration response, the IVIS is particularly effective for near-fault earthquakes or near-resonant excitations, but is less effective for far-field earthquakes with more high-frequency contents, as compared with the traditional system.

  13. Passive seismic experiment - A summary of current status. [Apollo-initiated lunar surface station data

    NASA Technical Reports Server (NTRS)

    Latham, G. V.; Dorman, H. J.; Horvath, P.; Ibrahim, A. K.; Koyama, J.; Nakamura, Y.

    1978-01-01

    The data set obtained from the four-station Apollo seismic network including signals from approximately 11,800 events, is surveyed. Some refinement of the lunar model will result, but its gross features remain the same. Attention is given to the question of a small, molten lunar core, the answer to which remains dependent on analysis of signals from a far side impact. Seventy three sources of repeating, deep moonquakes have been identified, thirty nine of which have been accurately located. Concentrated at depths from 800 to 1000 km, the periodicities of these events have led to the hypothesis that they are generated by tidal stresses. Lunar seismic data has also indicated that the meteoroid population is ten times lower than originally determined from earth based observations. Lunar seismic activity is much lower and mountainous masses show no sign of sinking, in contrast to earth, as a result of the lunar crust being four times thicker. While much work remains to be done, significant correlation between terrestrial and lunar observations can be seen.

  14. In/dependent Collaborations: Perceptions and Experiences of African Scientists in Transnational HIV Research

    PubMed Central

    Moyi Okwaro, Ferdinand; Geissler, P. W.

    2015-01-01

    This article examines collaboration in transnational medical research from the viewpoint of African scientists working in partnerships with northern counterparts. It draws on ethnographic fieldwork in an HIV laboratory of an East African state university, with additional data from interviews with scientists working in related research institutions. Collaboration is today the preferred framework for the mechanisms by which northern institutions support research in the south. The concept signals a shift away from the legacy of unequal (post‐) colonial power relations, although, amid persisting inequalities, the rhetorical emphasis on equality might actually hinder critical engagement with conflicts of interest and injustice. To collaborate, African scientists engage various strategies: They establish a qualified but flexible, non‐permanent workforce, diversify collaborators and research areas, source complementary funding to assemble infrastructures, and maintain prospective research populations to attract transnational clinical trials. Through this labor of collaboration, they sustain their institutions under prevailing conditions of scarcity. PMID:25800667

  15. Experiences of and responses to HIV among African and Caribbean communities in Toronto, Canada.

    PubMed

    Gardezi, F; Calzavara, L; Husbands, W; Tharao, W; Lawson, E; Myers, T; Pancham, A; George, C; Remis, R; Willms, D; McGee, F; Adebajo, S

    2008-07-01

    African and Caribbean communities in Canada and other developed countries are disproportionately affected by HIV/AIDS. This qualitative study of African and Caribbean communities in Toronto sought to understand HIV-related stigma, discrimination, denial and fear, and the effects of multiple intersecting factors that influence responses to the disease, prevention practices and access to treatment and support services. Semi-structured interviews were conducted with 30 HIV-positive men and women and focus groups were conducted with 74 men and women whose HIV status was negative or unknown. We identified a range of issues faced by African and Caribbean people that may increase the risk for HIV infection, create obstacles to testing and treatment and lead to isolation of HIV-positive people. Our findings suggest the need for greater sensitivity and knowledge on the part of healthcare providers; more culturally specific support services; community development; greater community awareness; and expanded efforts to tackle housing, poverty, racism and settlement issues.

  16. Sexual Decision Making in the Absence of Choice: The African American Female Dating Experience

    PubMed Central

    Andrasik, Michele P.; Nguyen, Hong V.; George, William H.; Kajumulo, Kelly F.

    2016-01-01

    Although links between low mate availability and increased HIV and STI risk for African American women have been documented in the literature, we know little about the impact of limited mate choices on the quality of relationships between Black men and women and how these relationship dynamics impact risk for young Black women. We conducted a qualitative study with African American female young adults (N=12) to explore the perceived impact of structural forces on African American female young adults’ dating and sexual behavior. Participants reported (1) perceptions of Black men as untrustworthy and manipulative, (2) the limited and often negative roles for Black men in the larger Black community, and (3) heterosexual relationships in the Black community as increasingly influenced by economics and commerce. Recommendations for HIV prevention interventions that include micro and macro level approaches are discussed. PMID:27182463

  17. In/dependent Collaborations: Perceptions and Experiences of African Scientists in Transnational HIV Research.

    PubMed

    Moyi Okwaro, Ferdinand; Geissler, P W

    2015-12-01

    This article examines collaboration in transnational medical research from the viewpoint of African scientists working in partnerships with northern counterparts. It draws on ethnographic fieldwork in an HIV laboratory of an East African state university, with additional data from interviews with scientists working in related research institutions. Collaboration is today the preferred framework for the mechanisms by which northern institutions support research in the south. The concept signals a shift away from the legacy of unequal (post-) colonial power relations, although, amid persisting inequalities, the rhetorical emphasis on equality might actually hinder critical engagement with conflicts of interest and injustice. To collaborate, African scientists engage various strategies: They establish a qualified but flexible, non-permanent workforce, diversify collaborators and research areas, source complementary funding to assemble infrastructures, and maintain prospective research populations to attract transnational clinical trials. Through this labor of collaboration, they sustain their institutions under prevailing conditions of scarcity.

  18. Development and validation of measures of religious involvement and the cancer experience among African Americans

    PubMed Central

    Holt, Cheryl L.; Caplan, Lee; Schulz, Emily; Blake, Victor; Southward, Vivian L.; Buckner, Ayanna V.

    2013-01-01

    Research indicates that African Americans diagnosed with cancer tend to use religion in coping, however less is known about the specific role that religion plays in the coping process. Based on previous qualitative work, five instruments were developed to assess the role of religious involvement in cancer coping: God as helper, God as healer, Faith in healing, Control over cancer, and New perspective. The instruments were administered to 100 African Americans with cancer. Each exhibited high internal reliability, and concurrent and discriminant validity. These instruments may have applied value for the development of church-based cancer support/survivorship interventions. PMID:19383653

  19. Fault structure, stress, or pressure control of the seismicity in shale? Insights from a controlled experiment of fluid-induced fault reactivation

    NASA Astrophysics Data System (ADS)

    De Barros, Louis; Daniel, Guillaume; Guglielmi, Yves; Rivet, Diane; Caron, Hervé; Payre, Xavier; Bergery, Guillaume; Henry, Pierre; Castilla, Raymi; Dick, Pierre; Barbieri, Ernesto; Gourlay, Maxime

    2016-06-01

    Clay formations are present in reservoirs and earthquake faults, but questions remain on their mechanical behavior, as they can vary from ductile (aseismic) to brittle (seismic). An experiment, at a scale of 10 m, aims to reactivate a natural fault by fluid pressure in shale materials. The injection area was surrounded by a dense monitoring network comprising pressure, deformation, and seismicity sensors, in a well-characterized geological setting. Thirty-two microseismic events were recorded during several injection phases in five different locations within the fault zone. Their computed magnitude ranged between -4.3 and -3.7. Their spatiotemporal distribution, compared with the measured displacement at the injection points, shows that most of the deformation induced by the injection is aseismic. Whether the seismicity is controlled by the fault architecture, mineralogy of fracture filling, fluid, and/or stress state is then discussed. The fault damage zone architecture and mineralogy are of crucial importance, as seismic slip mainly localizes on the sealed-with-calcite fractures which predominate in the fault damage zone. As no seismicity is observed in the close vicinity of the injection areas, the presence of fluid seems to prevent seismic slips. The fault core acts as an impermeable hydraulic barrier that favors fluid confinement and pressurization. Therefore, the seismic behavior seems to be strongly sensitive to the structural heterogeneity (including permeability) of the fault zone, which leads to a heterogeneous stress response to the pressurized volume.

  20. Academically Successful African American Male Urban High School Students' Experiences of Mattering to Others at School

    ERIC Educational Resources Information Center

    Tucker, Catherine; Dixon, Andrea; Griddine, Ke'Shana

    2010-01-01

    Mattering to others has been shown to be a key construct of mental health and wellness. Emerging research links interpersonal mattering and school climate. In this study, the authors use transcendental phenomenology to explore how interpersonal mattering impacts the academic achievement of urban African American males who are academically…

  1. The Power of Peers: Influences on Postsecondary Education Planning and Experiences of African American Students

    ERIC Educational Resources Information Center

    Holland, Nicole E.

    2011-01-01

    This investigation demonstrates the effect that peers have on students' academic engagement and educational aspirations. Forty-nine African American university students retrospectively discuss the manner by which their friends influenced their academic commitment and activity while in high school; their postsecondary education aspirations,…

  2. Till Death Do Us Part: Lived Experiences of HIV-Positive Married African American Women

    ERIC Educational Resources Information Center

    Edwards, Lorece V.; Irving, Shalon M.; Hawkins, Anita S.

    2011-01-01

    HIV/AIDS disease continues to be an escalating health problem, particularly among women. However, African American women are among the leading demographic groups for HIV prevalence in the United States. The typical woman with HIV/AIDS is young, in her late twenties, economically challenged, and of childbearing age. Participants were recruited from…

  3. Towards a Meaningful Curriculum Implementation in South African Schools: Senior Phase Teachers' Experiences

    ERIC Educational Resources Information Center

    Taole, Matshidiso Joyce

    2015-01-01

    Different sectors of society register complaints about schooling in South Africa. Given that curriculum reform has such a poor record of implementation in the country, there is clearly a need for research that identifies factors that hinder or facilitate curriculum implementation in South African schools and identifies strategies to address the…

  4. A Vision to Serve: The Experiences of Five African American Urban Teacher Leaders

    ERIC Educational Resources Information Center

    Watson, Allyson

    2007-01-01

    History denotes a small number of African-Americans have held leadership roles in educational public and private school systems across the country. However, during the last decade black women have pioneered and forged new frontiers as educational as leaders within urban schools. Because of these contributions, more should be known regarding the…

  5. The Outdoor Recreation Experience: Factors Affecting Participation of African American Women.

    ERIC Educational Resources Information Center

    Roberts, Nina S.; Drogin, Ellen B.

    1993-01-01

    Discusses factors contributing to the nonparticipation of African-American women in outdoor recreation activities including (1) historical oppression and racism; (2) stereotyping by race and gender; (3) lack of role models; (4) insufficient exposure to activity options; (5) limited accessibility to outdoor recreation areas; and (6) oppressive…

  6. African American Faculty Women Experiences of Underrepresentation in Computer Technology Positions in Higher Education

    ERIC Educational Resources Information Center

    King, Dolores

    2013-01-01

    African American women are underrepresented in computer technology disciplines in institutions of higher education throughout the United States. Although equitable gender representation is progressing in most fields, much less information is available on why institutions are still lagging in workforce diversity, a problem which can be lessened by…

  7. The Invisible Wall: Exploring the Experiences of African-American Students at CCCU Institutions

    ERIC Educational Resources Information Center

    Young, Timothy Perry

    2013-01-01

    African-American students who attend a CCCU institution do not complete their degrees as frequently as other student groups. The average gap at CCCU institutions between "overall and Black graduation rates is more than 19%. This is greater than the gap at other private institutions" (Smith, 2009, p.80). While the six-year graduation rate…

  8. A Dream Deferred: The Experience of an African American Student in a Doctoral Program in Science

    ERIC Educational Resources Information Center

    Green, Andre M.

    2008-01-01

    Due to a negative stigma that has been established about African Americans, many live their entire lives trying to "refute the degrading, humiliating and offensive racial images and stereotypes" that have plagued their race in scientific fields and in other areas of life. The images that are perpetuated have caused frustration as well as…

  9. Sense of Belonging and Student Success: An Analysis of Student Experiences in South African Universities

    ERIC Educational Resources Information Center

    Williams, Theresa

    2012-01-01

    Retention and graduation are major challenges in South African higher education institutions. These phenomena are especially troubling among Black and Colored (BC) students at both historically advantaged and historically disadvantaged institutions. The retention and graduation rates of these groups are disturbingly low compared to those of White…

  10. The Stuff of Stereotypes: Toward Unpacking Identity Threats amid African American Students' Learning Experiences

    ERIC Educational Resources Information Center

    Larnell, Gregory V.; Boston, Denise; Bragelman, John

    2014-01-01

    The purpose of this article is to shed light on scenarios in which threatening stereotypes unfold, specifically in an institutional context in which African Americans are overrepresented. Drawing on data and findings from a recent study examining mathematics learning and identity in non-credit-bearing remedial math courses, we present three…

  11. What Makes African American Health Disparities Newsworthy? An Experiment among Journalists about Story Framing

    ERIC Educational Resources Information Center

    Hinnant, Amanda; Oh, Hyun Jee; Caburnay, Charlene A.; Kreuter, Matthew W.

    2011-01-01

    News stories reporting race-specific health information commonly emphasize disparities between racial groups. But recent research suggests this focus on disparities has unintended effects on African American audiences, generating negative emotions and less interest in preventive behaviors (Nicholson RA, Kreuter MW, Lapka C "et al." Unintended…

  12. "I Understand the Struggle": Leveraging the Lived Experiences of African American Teachers in TESOL

    ERIC Educational Resources Information Center

    Siefert, Bobbi; Salas, Spencer; D'amico, Mark M.

    2015-01-01

    Although TESOL in-service teacher education committed to "culturally sustaining pedagogy" (Paris, 2012) has underscored the critical role of teachers' professional subjectivities for student achievement, relatively few studies have attempted to capture the perspectives of African American classroom teachers working with English language…

  13. Understanding the Breast Cancer Experience of Survivors: a Qualitative Study of African American Women in Rural Eastern North Carolina.

    PubMed

    Torres, Essie; Dixon, Crystal; Richman, Alice R

    2016-03-01

    The purpose of this study is to gain an in-depth understanding of African American breast cancer survivors' experiences, barriers and facilitators in accessing breast cancer treatment, and challenges in adherence to follow-up care. We conducted seven focus groups with 32 African American women with breast cancer in three rural counties in eastern North Carolina during August-November 2013. Surveys were also utilized to gather basic demographic and breast health history information. Thematic analysis was performed using the immersion crystallization approach. Several common areas of life affected by breast cancer included faith and support networks, psychosocial well-being, and quality of care issues. Faith in God was an important coping mechanism essential to all women in the study and a critical facilitator in survivorship. Support networks consisted of family, church-family, friends, and co-workers. The concept of fear included the discovery of breast cancer and fear of death, negative side effects of treatment, and social stigma of having breast cancer. Factors that influenced provider-patient relationship were age of provider, perceived lack of empathy, and providers leaving during treatment. Participants also expressed their lack of knowledge regarding a number of the side effects they were experiencing during and after their treatment. Results of this study contribute to the assessment of potential coping mechanisms used by African American breast cancer survivors (i.e., spirituality, positive attitudes, and support networks) that can potentially be effective and have a positive impact on the adjustment of life for survivors.

  14. COOL: Crust of the Oman Ophiolite and its Lithosphere - a passive seismic experiment

    NASA Astrophysics Data System (ADS)

    Weidle, Christian; Agard, Philippe; Ducassou, Céline; El-Hussain, Issa; Prigent, Cécile; Meier, Thomas

    2014-05-01

    Plate tectonics has established a framework for geoscientists to understand most geologic/tectonic processes that shaped our present-day Earth. 'Obduction', the emplacement of young, dense oceanic lithosphere (ophiolites) on top of older lighter continental lithosphere remains, however, a rather odd phenomenon. Some ophiolites are fundamentally similar to young oceanic crust and it is hence assumed that they were obducted as thrust sheets at the onset of continental subduction in a previously intra-oceanic subduction setting. The Peri-Arabic obduction corresponded to a spectacular, almost synchronous thrust movement along thousands of km from Turkey to Oman. At the eastern margin of the Arabian plate, the world's largest and best preserved ophiolite was emplaced in only a few My during Upper Cretaceous and is exposed today atop the Oman Mountain range. Although being the best studied ophiolite in the world, rather little is still known about the internal structure of the ophiolite and the Oman Mountains. The dimension of the ophiolite is large enough (~700 km) to be studied with seismological methods, providing thus a rare setting to investigate oceanic crust on land without ocean bottom installations. We have deployed a network of 40 broadband seismometers across the Oman Mountains in Oct/Nov 2013 for passive seismic registration for a duration of ca. 15 months. The network is complemented by 10 permanent stations in the area operated by the Earthquake Monitoring Center in Oman. Aims of the project include: - Seismological imaging of the geometry and internal properties of obducted oceanic, and its underlying continental lithosphere. - Regional tomographic velocity models will provide constraints on geodynamic processes that led to large scale obduction. - Investigating the "quiet" Makran subduction zone for local seismicity will improve understanding of seismic hazard on the eastern Arabian plate.

  15. Lithology, stress or pressure control of the seismicity in shale? Insights from a controlled experiment of fluid-induced fault reactivation

    NASA Astrophysics Data System (ADS)

    Rivet, D.; De Barros, L.; Daniel, G.; Guglielmi, Y.; Castilla, R.

    2015-12-01

    Shale materials are important components in petroleum systems (e.g. sealing and source rocks) and play an important role in earthquake faults. However, their mechanical behavior is still poorly understood, as it can vary from plastic to brittle. The role of fluid pressure in seismicity triggering is also not fully understood. A unique, decametric scale experiment, which aims at reactivating a natural fault by high pressure injection, was performed in shale. The injection interval was surrounded by a dense monitoring network of pressure, deformation and seismic sensors, in a well-characterized geological setting. 37 seismic events, with very small magnitude (about -4) were recorded during five series of injections within the fault zone. The spatio-temporal distribution of these events, compared with the measured displacement at the injection points, shows that most of the induced deformation is aseismic. The locations of the microseismic events are strongly asymmetrical, with most events distributed East of the fault and South of the injection area. Focal mechanisms are predominantly consistent with shear slip on a family of calcified fractures. The shale mineralogy appears to be a critical parameter governing the seismogenic character of deformation, as only calcified structures slipped seismically. As no seismic event occurs in the close vicinity of the injection, high-fluid content seems to inhibit seismic slip. Consequently, stress changes induced by this highly-pressurized volume should more likely influence the spatial distribution of seismicity. Finally, the main fault, acting as a fluid flow and/or stress barrier, strongly modifies the stress transfer. From the monitoring point of view, this experiment reflects the difficulty in quantitatively following fluid propagation in a shale formation, as seismicity will be strongly influenced by the presence of calcified fractures and by the interaction between stress transfer and lithological heterogeneities.

  16. Magmatic underplating and crustal growth in the Emeishan Large Igneous Province, SW China, revealed by a passive seismic experiment

    NASA Astrophysics Data System (ADS)

    Chen, Yun; Xu, Yigang; Xu, Tao; Si, Shaokun; Liang, Xiaofeng; Tian, Xiaobo; Deng, Yangfan; Chen, Lin; Wang, Peng; Xu, Yihe; Lan, Haiqiang; Xiao, Fuhui; Li, Wei; Zhang, Xi; Yuan, Xiaohui; Badal, José; Teng, Jiwen

    2015-12-01

    In an attempt to characterize the subsurface structure that is related to fossil mantle plume activity, a comprehensive geophysical investigation was conducted in the Emeishan Large Igneous Province (ELIP). The nature and geometry of the crust were examined within the scheme of the domal structure of ELIP, which comprises the Inner, Intermediate and Outer zones, which are defined on the basis of the biostratigraphy of pre-volcanic sediments. The bulk crustal properties within the Inner Zone are characterized by high density, high P-wave velocity, high Vp/Vs ratios and large crustal thickness. A visible continuous seismic converter is present in the upper part of the crust in the whole Intermediate Zone and the eastern part of the Inner Zone, but it is absent in the Inner Zone, where another seismic converter is observed in the lower part of the crust. The geometric configuration of these converters is attributable to the addition of mantle-derived melts to the pre-existing crust and subsequent interaction between them. The crustal geometry, which is delineated by the migrated image of receiver functions from the passive seismic experiment, and the crustal properties collectively suggest that a mafic layer of 15-20 km thickness and 150-180 km width exists at the base of the crust in the Inner Zone. Such a mafic layer reflects a vertical crustal growth through magmatic underplating at the base of the crust and intraplating within the upper crust. The salient spatial correlation between the deep crustal structure and the dome strongly supports a genetic link between crustal thickening and plume activity, if the pre-volcanic domal uplift is generated by the Permian Emeishan mantle plume. This arrangement is further supported by the consistency of the extent of crustal uplift estimated by isostatic equilibrium modeling and sedimentary data. This study therefore characterizes and provides evidence for a plume-modified crust in a large igneous province.

  17. High precision finite-differences time-domain direct modelling of wave equation for seismic oceanography experiments

    NASA Astrophysics Data System (ADS)

    Sallares, V.; Kormann, J.; Cobo, P.; Biescas, B.; Carbonell, R.

    2007-05-01

    Holbrook et al. (2003) demonstrated recently the possibility of visualizing fine structures in the water column, like thermohaline intrusion or internal waves, through seismic exploration experiments. Seismic exploration is becoming a popular technique for providing high-lateral resolution images of the explored area, in contrast with the classical oceanography probes, like XBT or XCDT. In this work we present a wave propagation model based upon a high order finite-differences time-domain (FDTD) scheme which includes special absorbing conditions in the boundaries. FDTD algorithms are known for presenting problems with reflections on the computational edges. Classical boundary conditions, like those of Engquist, provide reflection coefficients or the order of 10-2. However, reflection coefficients of fine structures in the water we are trying to model are about 10-4. Thus, the key point of the algorithm we present is in the implementation of Perfectly Matched Layer (PML) boundary conditions. These consist in zones with high absorption (therefore, very low reflection coefficient). The PML implemented in this scheme consists in a second order algorithm in the time domain, to take advantage of its stability and convergence properties. In this work we specify the propagation algorithm, and compare it results with the with Engquist and PML absorbing boundaries conditions. The PML condition affords reflection coefficients in the numerical edges lower than 10-4. Holbrook, W.S., Paramo, P., Pearse, S. and Schmitt, R.W., 2003. Thermohaline fine structure in an oceanographic front from seismic reflection profiling. Science, 301, 821-824.

  18. Effect of the surface roughness on the seismic signal generated by a single rock impact: insight from laboratory experiments

    NASA Astrophysics Data System (ADS)

    Bachelet, Vincent; Mangeney, Anne; de Rosny, Julien; Toussaint, Renaud

    2016-04-01

    The seismic signal generated by rockfalls, landslides or avalanches is a unique tool to detect, characterize and monitor gravitational flow activity, with strong implication in terms of natural hazard monitoring. Indeed, as natural flows travel down the slope, they apply stresses on the ground, generating seismic waves in a wide frequency band. Our ultimate objective is to relate the granular flow properties to the generated signals that result from the different physical processes involved. We investigate here the more simple process: the impact of a single bead on a rough surface. Farin et al. [2015] have already shown theoretically and experimentally the existence of a link between the properties of an impacting bead (mass and velocity) on smooth surfaces, and the emitted signal (radiated elastic energy and mean frequency). This demonstrates that the single impactor properties can be deduced from the form of the emitted signal. We extend this work here by investigating the impact of single beads and gravels on rough and erodible surfaces. Experimentally, we drop glass and steel beads of diameters from 2 mm to 10 mm on a PMMA plate. The roughness of this last is obtained by gluing 3mm-diameter glass beads on one of its face. Free beads have been also added to get erodible beds. We track the dropped impactor motion, times between impacts and the generated acoustic waves using two fast cameras and 8 accelerometers. Cameras are used in addition to estimate the impactor rotation. We investigate the energy balance during the impact process, especially how the energy restitution varies as a function of the energy lost through acoustic waves. From these experiments, we clearly observe that even if more dissipative processes are involved (friction, grain reorganization, etc.), the single bead scaling laws obtained on smooth surfaces remain valid. A main result of this work is to quantify the fluctuations of the characteristic quantities such as the bounce angle, the

  19. Termination of the Batholiths marine seismic experiment: the scientific method loses to hearsay

    NASA Astrophysics Data System (ADS)

    Hollister, L. S.

    2007-12-01

    The marine seismic component of the NSF-Continental Dynamics funded project Batholiths was terminated by Canadian authorities due to environmental concerns. Socioeconomic benefits of the project were not taken into account, nor were findings by the National Research Council on effects of ocean noise on marine mammal populations. The marine seismic component of Batholiths was to have been done using sound from airguns towed behind the R/V Langseth in order to seismically image the geologic structures below the Coast Mountains of British Columbia. The project was nearly identical in timing, location, and scope to the ACCRETE project, which was successfully permitted and done in the early fall of 1994, with no detected or known damage to the environment. However, what changed in the last 13 years was a dramatic increase of concern by eNGOs (environmental non- government organizations) that airguns produced sound that might be harmful to marine species, marine mammals in particular. The marine noise concerns were amplified by eNGO agendas and campaigns to prevent oil exploration along continental margins and to shut down naval exercises involving sonar to detect submarines. Compared to these agendas, Batholiths was an easy target because the PIs (Principal Investigators) did not have the manpower or financial or legal resources (in contrast to the Navy and oil companies) to push back against an organized campaign set on stopping Batholiths. The main concern used to mobilize public opinion against Batholiths was that, if we were permitted, then oil exploration in the nearby region would be permitted; and, if oil were found, drilling would proceed: the slippery slope argument. Thus, by stopping Batholiths with the speculation that airgun noise, as used in a marine seismic study, might damage marine life, the eNGOs believe they have stopped oil exploration in British Columbia coastal waters. It is widely recognized that everything was done right to get the permits for

  20. Deviant bodies, stigmatized identities, and racist acts: examining the experiences of African-American gamers in Xbox Live

    NASA Astrophysics Data System (ADS)

    Gray, K. L.

    2012-12-01

    The purpose of this article is to illustrate how minority gamers, particularly African-American males, are subject to the label of deviant within the virtual gaming community of Xbox Live. They are labeled deviant based on the stigma of their physical identity - blackness, through a process of linguistic profiling. By employing virtual ethnography, the author identifies a process that leads to racism based on how the black gamer sounds within the space. The act of racism emerges through a process involving questioning, provoking, instigating, and ultimately racism. Many black gamers have normalized these racist experiences and have accepted the label of deviant placed upon their bodies.

  1. Dry intrusions in the West African monsoon mid-troposphere during the AMMA experiment

    NASA Astrophysics Data System (ADS)

    Deme, A.; Roca, R.

    2009-04-01

    Mid-troposphere dry air patches (RH < 10%) have been recently detected over the African monsoon region and in particular over Sahel. At 500 hPa, these dry air features are thought to play a complex role onto convection: inhibition isolated convective cells but favouring already organized convection by feeding rear-inflow currents with dry air. The inhibiting action of the dry air onto convection comes from the temperature inversion induced by radiation at the bottom of the dry layer and/or by entrainment of dry air in ascending parcel that decreases its buoyancy. The organizing effect is associated to mesoscale currents within and around long lasting squall lines. This mid-tropospheric dry air has been shown to originate from the mid-latitudes upper level jets, therefore coined extra-tropical dry intrusions.Among all the forcings that control the dynamics of the West African monsoon, the role of a dry mid-troposphere needs to be clarified. The present study is dedicated to this objective and it is focused on extra-tropical dry air intrusions in the West African mid-troposphere during the AMMA campaign. The low level dynamics is documented (African Easterly Jet, African Easterly Wave) thanks to the NCEP operational analysis. It is completed by the radiosondes especially for the temperature and water vapor distribution. Back-trajectory are computed in order to highlight the origin of the tropospheric air mass. Finally Meteosat Second Generation derived water vapor and cloud and rainfall parameters are used to characterize the convective activity and its moist environment. Dry intrusions in the African mid troposphere during the summer 2006 have been shown to be associated with two major modes of occurrences: a 40-50 days mode and a 10-20 days mode. The long mode exhibits negative anomaly of the rainfall and a very large scale structure covering the whole West Africa region when occurring while the short mode is more restricted to the Sahelian longitude. Similarly

  2. The Impact of African American Parents' Racial Discrimination Experiences and Perceived Neighborhood Cohesion on their Racial Socialization Practices.

    PubMed

    Saleem, Farzana T; English, Devin; Busby, Danielle R; Lambert, Sharon F; Harrison, Aubrey; Stock, Michelle L; Gibbons, Frederick X

    2016-07-01

    Parental racial socialization is a parenting tool used to prepare African American adolescents for managing racial stressors. While it is known that parents' racial discrimination experiences affect the racial socialization messages they provide, little is known about the influence of factors that promote supportive and communal parenting, such as perceived neighborhood cohesion. In cohesive neighborhoods, neighbors may help parents address racial discrimination by monitoring youth and conveying racial socialization messages; additionally, the effect of neighborhood cohesion on parents' racial socialization may differ for boys and girls because parents socialize adolescents about race differently based on expected encounters with racial discrimination. Therefore, the current study examines how parents' perception of neighborhood cohesion and adolescents' gender moderate associations between parents' racial discrimination experiences and the racial socialization messages they deliver to their adolescents. Participants were a community sample of 608 African American adolescents (54 % girls; mean age = 15.5) and their primary caregivers (86 % biological mothers; mean age = 42.0). Structural equation modeling indicated that parental racial discrimination was associated with more promotion of mistrust messages for boys and girls in communities with low neighborhood cohesion. In addition, parental racial discrimination was associated with more cultural socialization messages about racial pride and history for boys in neighborhoods with low neighborhood cohesion. The findings suggest that parents' racial socialization messages are influenced by their own racial discrimination experiences and the cohesiveness of the neighborhood; furthermore, the content of parental messages delivered varies based on adolescents' gender. PMID:27189721

  3. Calibration formulae and values for velocity seismometers used in the 1998 Santa Clara Valley, California seismic experiment

    USGS Publications Warehouse

    Lindh, Allan G.; Eaton, Jerry P.; O'Neill Allen, Mary; Healy, John H.; Stewart, Samuel W.; Damerell, Lu

    1999-01-01

    Eaton (1975), Bakun and Dratler (1976), Eaton (1977), Healy and O’Neil (1977), Asten (1977), Stewart and O'Neill (1980), Liu and Peselnick (1986), Eaton (1991), Rodgers et al. (1995), and many others (see Asten (1977) for a list of earlier references) have presented formulae for calculating the damped generator constant (or motor constant), and the damping constant (or fractional damping ratio) for magnetically damped velocity seismometers. Unfortunately the notation varies between authors, and not all the formulae allow for some of the significant variables -- differences in input impedance of the recording system in particular. This has become particularly relevant because the USGS seismic networks in California have traditionally set up their velocity sensors for the 10K Ohm impedance of the standard USGS analog telemetry systems (Eaton, 1977), but modern digital recording systems are usually set up with high input impedances, often of a megaohm or greater. Thus the nominal calibration values valid for USGS velocity sensors in their “normal” configuration are incorrect when they are recorded on other systems. In this short note we have collected the relevant formulae needed, and computed the seismometer responses for the various velocity sensors used in the recent Santa Clara Valley Seismic Experiment (SCVSE, see Lindh et al., 1999).

  4. DIRECT COURSE-TRINITY seismic experiment. Final report, July 1983-July 1984

    SciTech Connect

    Reinke, R.E.

    1986-06-01

    The proximity of the DIRECT COURSE test site to the TRINITY site where the first atomic bomb was detonated in July 1945 offered a unique opportunity to compare the unusual appearing seismic waves recorded on the TRINITY event with those excited by DIRECT COURSE. Two of the Leet Seismographs used to record the 1945 TRINITY event were obtained and fielded on DIRECT COURSE alongside modern digital instrumentation in an effort to verify the TRINITY seismograms. Good records were obtained from one of the Leet instruments and from most of the digital instrumentation. Comparison between the Leet records and the digital seismograms indicates that the hydrodynamic wave, first observed at TRINITY, is real and not an instrument phenomenon.

  5. Simulation of complete seismic surveys for evaluation of experiment design and processing

    SciTech Connect

    Oezdenvar, T.; McMechan, G.A.; Chaney, P.

    1996-03-01

    Synthesis of complete seismic survey data sets allows analysis and optimization of all stages in an acquisition/processing sequence. The characteristics of available survey designs, parameter choices, and processing algorithms may be evaluated prior to field acquisition to produce a composite system in which all stages have compatible performance; this maximizes the cost effectiveness for a given level of accuracy, or for targets with specific characteristics. Data sets synthesized for three salt structures provide representative comparisons of time and depth migration, post-stack and prestack processing, and illustrate effects of varying recording aperture and shot spacing, iterative focusing analysis, and the interaction of migration algorithms with recording aperture. A final example demonstrates successful simulation of both 2-D acquisition and processing of a real data line over a salt pod in the Gulf of Mexico.

  6. The Tectonic Evolution of SE Canada: Seismic Evidence from the QM-III Experiment

    NASA Astrophysics Data System (ADS)

    Bastow, I. D.; Boyce, A.; Darbyshire, F. A.; Levin, V. L.; Menke, W. H.; Ellwood, A.

    2014-12-01

    Much of the geological record can be interpreted in the context of processes operating today at plate boundaries. This works well to explain processes and products during the Phanerozoic era; during Precambrian times when the oldest rocks were forming, however, conditions on the younger, hotter, more ductile Earth were likely very different, making analogies with modern day tectonics less certain. Gathering evidence preserved deep within the plates in the shields is thus essential to improve our understanding of the early Earth. Shields are usually underlain by thick, seismically fast roots that are absent beneath younger portions of Earth's surface. The thermochemically distinct nature of cratonic roots is often associated with Archean processes such as the extraction of komatiitic magmas. However, the cratonic core of North America does not fit easily into this Archean formation paradigm: part of the Canadian shield extends beneath the Archean Superior craton, but much of it persists beneath younger Proterozoic crust as well. We present here a relative arrival-time tomographic study of mantle seismic structure using data from a new seismograph network operating in SE Canada. Our stations extend from the Archean Superior craton around the southern tip of Hudson Bay, through Proterozoic Grenville terranes, and into Paleozoic coastal Maine and Nova Scotia. Tomographic images display three broad zones of mantle wavespeed: slow in the Appalachian terranes; fast in the Grenville Province; very fast within the Superior craton. Archean lithosphere has been modified by the Great Meteor hotspot, but we find no evidence for major plate-scale underthrusting during the Grenville orogeny. The abrupt wavespeed transition from Archean to Proterozoic mantle is thus consistent with the emerging consensus that keels form in two stages: a chemically depleted layer in Archean times followed by the thermal development of a less-depleted lithosphere during Proterozoic times.

  7. School Characteristics and Experiences of African American, Hispanic/Latino, and Native American Youth in Rural Communities: Relation to Educational Aspirations

    ERIC Educational Resources Information Center

    Irvin, Matthew J.; Byun, Soo-yong; Meece, Judith L.; Reed, Karla S.; Farmer, Thomas W.

    2016-01-01

    The primary purpose of this study was to examine differences in the school characteristics and experiences of African American, Hispanic/Latino, and Native American youth in rural high schools as well as their relation to educational aspirations. We also investigated the characteristics and experiences of students and their families given that…

  8. A Three-Day Seismic Experiment in an Urban Setting: An Introduction to Seismology for Minority Students

    NASA Astrophysics Data System (ADS)

    Lorenzo, J. M.; Anderson, L. C.; Bart, P. J.; Ferrell, R. E.; Tomkin, J. H.

    2004-12-01

    Summer program participants of LSU GAEMP (Geoscience Alliance to Improve Minority Participation) are non-traditional, STEM (science, technology, engineering, or math), underrepresented minorities from 9 Minority-Serving Institutions in the states of Louisiana, Texas and Mississippi. During this summer of 2004, twelve students completed a six-week field and lab program across the lower U.S.A. Because of the urban background of many of the participants one three-day module on earthquakes and earth deformation emphasized the design of a non-conventional seismic experiment, field acquisition and analysis of data in an urban setting. Day one introduced stress, major fault types and their plate tectonic setting based on a case study of active growth faulting, emphasizing its effects on urban planning. Students visited the field to verify the location of faults from prior interpretations using GPS and topographic maps, and to discuss observed faulted buildings, offices and roadways. Later, students were exposed to the principles of active seismology, divided into six working groups and required to design by the next morning a realistic experiment to verify faults in the shallow subsurface. Day two was dedicated to collecting shallow (<300m) shear-wave seismic refraction data from both sides of a suspected growth fault, with the student expectation that a thicker sediment sequence would be observed on the down-thrown block. Day three involved pencil-and-paper analyses of data for reflection and refraction-thickness and velocity estimation, capped with a discussion and formal oral presentations of group results. The student-led design, active field deployment of equipment and formal discussion groups provided the widest range of activities to promote awareness of the relevance of seismology in modern society.

  9. An in-situ stimulation experiment in crystalline rock - assessment of induced seismicity levels during stimulation and related hazard for nearby infrastructure

    NASA Astrophysics Data System (ADS)

    Gischig, Valentin; Broccardo, Marco; Amann, Florian; Jalali, Mohammadreza; Esposito, Simona; Krietsch, Hannes; Doetsch, Joseph; Madonna, Claudio; Wiemer, Stefan; Loew, Simon; Giardini, Domenico

    2016-04-01

    A decameter in-situ stimulation experiment is currently being performed at the Grimsel Test Site in Switzerland by the Swiss Competence Center for Energy Research - Supply of Electricity (SCCER-SoE). The underground research laboratory lies in crystalline rock at a depth of 480 m, and exhibits well-documented geology that is presenting some analogies with the crystalline basement targeted for the exploitation of deep geothermal energy resources in Switzerland. The goal is to perform a series of stimulation experiments spanning from hydraulic fracturing to controlled fault-slip experiments in an experimental volume approximately 30 m in diameter. The experiments will contribute to a better understanding of hydro-mechanical phenomena and induced seismicity associated with high-pressure fluid injections. Comprehensive monitoring during stimulation will include observation of injection rate and pressure, pressure propagation in the reservoir, permeability enhancement, 3D dislocation along the faults, rock mass deformation near the fault zone, as well as micro-seismicity. The experimental volume is surrounded by other in-situ experiments (at 50 to 500 m distance) and by infrastructure of the local hydropower company (at ~100 m to several kilometres distance). Although it is generally agreed among stakeholders related to the experiments that levels of induced seismicity may be low given the small total injection volumes of less than 1 m3, detailed analysis of the potential impact of the stimulation on other experiments and surrounding infrastructure is essential to ensure operational safety. In this contribution, we present a procedure how induced seismic hazard can be estimated for an experimental situation that is untypical for injection-induced seismicity in terms of injection volumes, injection depths and proximity to affected objects. Both, deterministic and probabilistic methods are employed to estimate that maximum possible and the maximum expected induced

  10. Experiences and effects of psychiatric stigma: Monologues of the stigmatizers and the stigmatized in an African setting

    PubMed Central

    Egbe, Catherine O.

    2015-01-01

    People with mental illness (PWMI) are faced with a number of social and health-related challenges especially stigma and discrimination which tend to have negative effects on their lives. This paper presents narrative monologues portraying the experiences and effects of psychiatric stigma and discrimination on PWMI in South Africa. These narratives voice out the concerns of the stigmatizers (specifically family members and significant others of PWMI) and the stigmatized in a poetic fashion. The society is still not very sympathetic to the plights of PWMI and this affects their general health and well-being. Traditional beliefs and prejudice still drive public attitude towards PWMI especially in African settings. These narratives presented in a poetic fashion in this paper highlight some salient issues relating to the experience and effects of stigma and the desires of PWMI to be treated with love and respect and helped to lead healthy normal lives. PMID:26088367

  11. Masculinity and the body: how African American and White men experience cancer screening exams involving the rectum.

    PubMed

    Winterich, Julie A; Quandt, Sara A; Grzywacz, Joseph G; Clark, Peter E; Miller, David P; Acuña, Joshua; Arcury, Thomas A

    2009-12-01

    Past research on prostate and colorectal cancer disparities finds that barriers to screening, such as embarrassment and offensiveness, are often reported. Yet none of this literature investigates why. This study uses masculinity and health theory to examine how men experience two common screenings: digital rectal exams (DREs) and colonoscopies. In-depth interviews were conducted with 64 African American and White men from diverse backgrounds, aged 40 to 64, from North Carolina. Regardless of race or education, men experienced DREs more negatively than colonoscopies because penetration with a finger was associated with a gay sexual act. Some men disliked colonoscopies, however, because they associated any penetration as an affront to their masculinity. Because beliefs did not differ by race, future research should focus on structural issues to examine why disparities persist with prostate and colorectal cancer. Recommendations are provided for educational programs and physicians to improve men's experiences with exams that involve the rectum.

  12. Wide-Angle Seismic Experiment Across the Oeste Fault Zone, Central Andes, Northern Chile.

    NASA Astrophysics Data System (ADS)

    Lorenzo, J. M.; Yáñez, G. A.; Vera, E. E.; Sepúlveda, J.

    2008-12-01

    From December 6-21, 2007, we conducted a 3-component, radio-telemetric, seismic survey along a ~ 15-km wide E-W transect in the Central Andes, at a latitude of ~ 22.41° S, centered north of the city of Calama (68.9° W), Chile. The study area is sandwiched between the Central Depression in the west and the Andean Western Cordillera of Chile. Recording stations, nominally spaced at intervals of either 125 or 250 m collected up to 3.5 s of refracted seismic arrivals at maximum source-receiver offsets exceeding 15 km. Ten shothole sources, spaced 2-6 km apart focused energy on the shallow (0-3 km), crustal, Paleogene-age structures. Preliminary, tomographic inversions of refracted first arrivals show the top of a shallow (< 1km), high- velocity (VP, ~5 km/s) crust, deepening sharply eastward to at least 2 km. At the surface, this central basement step correlates to a regionally extensive (> 600 km), strike-slip fault zone known as the Oeste fault. Turning ray densities suggest the base of the overlying velocity gradient unit (VP, 2-4 km/s) dips inwardly from both east and west directions toward the Oeste fault to depths of almost 1 km. Plate reorganization commencing at least by the latter half of the Oligocene led from oblique to more orthogonal convergence between the South American and the Nazca (Farallon) Plates. We interpret previously mapped, older, minor faults as being generated within the right-lateral, orogen-parallel, Oeste strike-slip fault zone, and postdated by Neogene, N-S striking thrust faults. In this context we also interpret that the spatial distribution of velocity units requires an period of extensional activity that may (1) postdate the transpressional strike slip fault activity of the Neogene, (2) be related to a later releasing bend through the translation and interaction of rigid blocks hidden at depth or even (3) be the consequence of inelastic failure from the result of flexural loading.

  13. The experience of the Antarctic Seismic Data Library System (SDLS) as a hub for researchers in antarctic crustal studies.

    NASA Astrophysics Data System (ADS)

    Diviacco, Paolo; Wardell, Nigel

    2010-05-01

    The SDLS was created in April 1991 under the auspices of the Scientific Committee on Antarctic Research to provide open access to Antarctic multichannel seismic-reflection data (MCS) for use in cooperative research projects. The SDLS operates under the mandates of the Antarctic Treaty System, by which all institutions that collect MCS data in Antarctica must submit their MCS data to the SDLS. The SDLS has library branches worldwide at which researchers may view and study the MCS data. MCS data are submitted to the SDLS within 4 years of collection and remain in the library under SDLS guidelines until 8 years after collection. Thereafter, the data go to World Data Centers or equivalents for unrestricted use. The SDLS offers a clearing house, based at Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS) where data are processed when needed and georeferenced, so that the end user can be provided with usable, although basic, post-stack seismic sections. Re-processing of data is beyond the scope of the SDLS, so that if a researcher is interested in reviewing pre-stack data he/she must resort to the data owner. So far 228,000 km of seismic data have been made public in all sectors of the Antarctic region. To augment the concept of physical repositories where data can be accessed by researchers travelling to one of the branches or from where data could be copied to digital media and sent to users, in 2003 it was decided to develop a web interface where data could be searched for and accessed directly. At that moment no previous non-commercial experience was available in this data field, so that the system was designed from scratch. Several technologies were introduced, tested, and after a period of use, reviewed and tuned. Particular attention was devoted to the seismic data viewing facility, which was tailored to the needs of a community with specific practices and legacies. Seismic data are sensitive data that are very important for the E&P industry, so

  14. Drawing the line: how African, Caribbean and White British women live out psychologically abusive experiences.

    PubMed

    Rivas, Carol; Kelly, Moira; Feder, Gene

    2013-09-01

    This study explores how African, Caribbean and White British women worked to hide psychological partner abuse as they experienced it, "do gender," and appear competent in social roles. They prioritized negotiated competencies as "good partners," actively setting socially and culturally embedded boundaries to their abuser's behaviors: an inner boundary encompassing normal behaviors and an outer one of "acceptable" behaviors projected as normal through remedial work. Behaviors breaching the outer boundary (e.g., if the women narrowed the bounds of the "acceptable") compromised the women's competence. This sometimes led them to actively use support services. Appropriate advice and support may change the boundaries.

  15. Seismic velocity structure and spatial distribution of reflection intensity off the Boso Peninsula, Central Japan, revealed by an ocean bottom seismographic experiment

    NASA Astrophysics Data System (ADS)

    Kono, Akihiro; Sato, Toshinori; Shinohara, Masanao; Mochizuki, Kimihiro; Yamada, Tomoaki; Uehira, Kenji; Shinbo, Takashi; Machida, Yuuya; Hino, Ryota; Azuma, Ryosuke

    2016-04-01

    Off the Boso Peninsula, central Japan, where the Sagami Trough is in the south and the Japan Trench is in the east, there is a triple junction where the Pacific plate (PAC), the Philippine Sea plate (PHS) and the Honshu island arc (HIA) meet each other. In this region, the PAC subducts beneath the PHS and the HIA, and the PHS subducts beneath the HIA. Due to the subduction of 2 oceanic plates, numerous seismic events took place in the past. In order to understand these events, it is important to image structure of these plates. Hence, many researchers attempted to reveal the substructure from natural earthquakes and seismic experiments. Because most of the seismometers are placed inland area and the regular seismicity off Boso is inactive, it is difficult to reveal the precise substructure off Boso area using only natural earthquakes. Although several marine seismic experiments using active sources were conducted, vast area remains unclear off Boso Peninsula. In order to improve the situation, a marine seismic experiment, using airgun as an active source, was conducted from 30th July to 4th of August, 2009. The survey line has 216 km length and 20 Ocean Bottom Seismometers (OBSs) were placed on it. We estimated 2-D P-wave velocity structure from the airgun data using the PMDM (Progressive Model Development Method; Sato and Kenett, 2000) and the FAST (First Arrival Seismic Tomography ; Zelt and Barton, 1998). Furthermore, we identified the probable reflection phases from the data and estimated the location of reflectors using Travel time mapping method (Fujie et al. 2006). We found some reflection phases from the data, and the reflectors are located near the region where P-wave velocity is 5.0 km/s. We interpret that the reflectors indicate the plate boundary between the PHS and the HIA. The variation of the intensity of reflection along the upper surface of PHS seems to be consistent with the result from previous reflection seismic experiment conducted by Kimura et

  16. Understanding the Breast Cancer Experience of Survivors: a Qualitative Study of African American Women in Rural Eastern North Carolina.

    PubMed

    Torres, Essie; Dixon, Crystal; Richman, Alice R

    2016-03-01

    The purpose of this study is to gain an in-depth understanding of African American breast cancer survivors' experiences, barriers and facilitators in accessing breast cancer treatment, and challenges in adherence to follow-up care. We conducted seven focus groups with 32 African American women with breast cancer in three rural counties in eastern North Carolina during August-November 2013. Surveys were also utilized to gather basic demographic and breast health history information. Thematic analysis was performed using the immersion crystallization approach. Several common areas of life affected by breast cancer included faith and support networks, psychosocial well-being, and quality of care issues. Faith in God was an important coping mechanism essential to all women in the study and a critical facilitator in survivorship. Support networks consisted of family, church-family, friends, and co-workers. The concept of fear included the discovery of breast cancer and fear of death, negative side effects of treatment, and social stigma of having breast cancer. Factors that influenced provider-patient relationship were age of provider, perceived lack of empathy, and providers leaving during treatment. Participants also expressed their lack of knowledge regarding a number of the side effects they were experiencing during and after their treatment. Results of this study contribute to the assessment of potential coping mechanisms used by African American breast cancer survivors (i.e., spirituality, positive attitudes, and support networks) that can potentially be effective and have a positive impact on the adjustment of life for survivors. PMID:25877467

  17. Calculation and experiment for dynamic response of bridge in deep water under seismic excitation

    NASA Astrophysics Data System (ADS)

    Liu, Chun-guang; Sun, Guo-shuai

    2014-08-01

    The fluid-structure interaction under seismic excitation is very complicated, and thus the damage identification of the bridge in deep water is the key technique to ensure the safe service. Based on nonlinear Morison equation considering the added mass effect and the fluid-structure interaction effect, the effect of hydrodynamic pressure on the structure is analyzed. A series of underwater shaking table tests are conducted in the air and in water. The dynamic characteristics affected by hydrodynamic pressure are discussed and the distribution of hydrodynamic pressure is also analyzed. In addition, the damage of structure is distinguished through the natural frequency and the difference of modal curvature, and is then compared with the test results. The numerical simulation and test of this study indicate that the effect of hydrodynamic pressure on the structure should not be neglected. It is also found that the presence of the damage, the location of the damage and the degree of the severity can be judged through the variation of structure frequency and the difference of modal curvature.

  18. The association between disaster-related experiences and mental health outcomes among drug using African American Hurricane Katrina evacuees.

    PubMed

    Cepeda, Alice; Saint Onge, Jarron M; Kaplan, Charles; Valdez, Avelardo

    2010-12-01

    This article provides a detailed examination of the relationship between disaster-related experiences and mental health outcomes among a sample of drug using African American Hurricane Katrina evacuees. Face-to-face structured interviews were administered to Hurricane Katrina evacuees (n = 350) residing in voucher assisted apartment complexes in Houston, Texas (2006-2007). We use Ordinary Least Squares and logistic regression models to examine both the relevance of disaster-related experiences and the interactive relationships between disaster-related experiences and post-disaster mental health outcomes including psychological distress, severe depression, somatic symptoms, and posttraumatic stress disorder. Results indicate that disaster-related experiences including negative life changes, disaster exposure, post-disaster stressors, and resource loss, have unique, inverse relationships with mental health. While resource loss has the strongest inverse relationship with mental health, disaster exposure has a negative interactive effect on psychological distress and anxiety. Although highly vulnerable populations report low levels of mental health nearly 2 years following a disaster experience, there is a convergence in mental health outcomes with high levels of disaster experiences and disaster exposure that suggests mental resiliency.

  19. Seismic hazard assessment of the Kivu rift segment based on a new sismo-tectonic zonation model (Western Branch of the East African Rift system)

    NASA Astrophysics Data System (ADS)

    Havenith, Hans-Balder; Delvaux, Damien

    2015-04-01

    In the frame of the Belgian GeoRisCA multi-risk assessment project focused on the Kivu and Northern Tanganyika Region, a seismic hazard map has been produced for this area. It is based on a on a recently re-compiled catalogue using various local and global earthquake catalogues. The use of macroseismic epicenters determined from felt earthquakes allowed to extend the time-range back to the beginning of the 20th century, thus spanning about 100 years. The magnitudes have been homogenized to Mw and the coherence of the catalogue has been checked and validated. The seismo-tectonic zonation includes 10 seismic source areas that have been defined on the basis of the regional geological structure, neotectonic fault systems, basin architecture and distribution of earthquake epicenters. The seismic catalogue was filtered by removing obvious aftershocks and Gutenberg-Richter Laws were determined for each zone. On the basis of this seismo-tectonic information and existing attenuation laws that had been established by Twesigomwe (1997) and Mavonga et al. (2007) for this area, seismic hazard has been computed with the Crisis 2012 (Ordaz et al., 2012) software. The outputs of this assessment clearly show higher PGA values (for 475 years return period) along the Rift than the previous estimates by Twesigomwe (1997) and Mavonga (2007) while the same attenuation laws had been used. The main reason for these higher PGA values is likely to be related to the more detailed zonation of the Rift structure marked by a strong gradient of the seismicity from outside the rift zone to the inside. Mavonga, T. (2007). An estimate of the attenuation relationship for the strong ground motion in the Kivu Province, Western Rift Valley of Africa. Physics of the Earth and Planetary Interiors 62, 13-21. Ordaz M, Martinelli F, Aguilar A, Arboleda J, Meletti C, D'Amico V. (2012). CRISIS 2012, Program for computing seismic hazard. Instituto de Ingeniería, Universidad Nacional Autónoma de M

  20. Lithospheric structure beneath Central Europe from the POLONAISE'97, CELEBRATION 2000, ALP 2002, and SUDETES 2003 seismic refraction experiments

    NASA Astrophysics Data System (ADS)

    Guterch, A.; Grad, M.; Keller, G. R.

    2005-12-01

    Beginning in 1997, Central Europe between the Baltic and Adriatic Seas, has been covered by an unprecedented network of seismic refraction experiments POLONAISE'97, CELEBRATION 2000, ALP 2002, and SUDETES 2003, have only been possible due to a massive international consortium consisted of more than 30 institutions from 16 countries in Europe and North America. The majority of recording instruments was provided by the IRIS/PASSCAL Instrument Center and the University of Texas at El Paso (USA), and several other countries also provided instrumentation. Total length of seismic profiles in all experiments is about 20,000 km. The main results of these experiments are: 1) the delineation of the deep structure of the southwestern margin of the East European Craton (southern Baltica) and its relationship to younger terranes; delineation of the major terranes and crustal blocks in the Trans European Suture Zone; determination of the structural framework of the Pannonian basin; elucidation of the deep structure and evolution of the Western Carpathian Mountains and Eastern Alps; determination of the structural relationships between the structural elements of the Bohemian massif and adjacent features; construction of 3-D models of the lithospheric structure; and evaluation and develop geodynamic models for the tectonic evolution of the region. Experiment Working Groups Members: K. Aric, M. Behm, E. Brueckl, W. Chwatal, H. Grassl, S. Hock, V. Hoeck, F. Kohlbeck, E.-M. Rumpfhuber, Ch. Schmid, R. Schmoller, C. Tomek, Ch. Ullrich, F.Weber (Austria), A.A. Belinsky (Belarus), I. Asudeh, R. Clowes, Z. Hajnal (Canada), F. Sumanova (Croatia), M. Broz , P. Hrubcova, M. Korn, O. Karousova, J. Malek, A. Spicak (Czech Republic), S.L. Jensen, P. Joergensen, H. Thybo (Denmark), K. Komminaho, U. Luosto, T. Tiira, J. Yliniemi (Finland), F. Bleibinhaus, R. Brinkmann, B. Forkmann, H. Gebrande, H. Geissler, A. Hemmann, G. Jentzsch, D. Kracke, A. Schulze, K. Schuster (Germany), T. Bodoky, T

  1. P-wave velocity structure of the southern Ryukyu margin east of Taiwan: Results from the ACTS wide-angle seismic experiment

    NASA Astrophysics Data System (ADS)

    Klingelhoefer, F.; Berthet, T.; Lallemand, S.; Schnurle, P.; Lee, C.-S.; Liu, C.-S.; McIntosh, K.; Theunissen, T.

    2012-11-01

    An active seismic experiment has been conducted across the southern Ryukyu margin east of Taiwan over the whole trench-arc-backarc system in May 2009. Twenty-four ocean bottom seismometers (OBS) were deployed from the Ryukyu trench to the southern Okinawa trough over the Ryukyu arc and forearc. Wide angle seismic data were recorded by the OBS array while coincident reflection seismic data were acquired using a 6 km long streamer and a 6600 cubic inch seismic airgun array. Results from tomographic inversion of 21091 travel time picks along this line allowed us to image crustal structures of the Ryukyu margin down to a depth of 25 km. The transect has been designed to provide a better seismic velocity structure of the subduction zone in a highly deformed area that has produced an M8 earthquake in 1920. The line crosses a seismic cluster of earthquakes which source mechanisms are still poorly understood. The subducting oceanic crust of the Huatung Basin is about 5-6 km thick. The underlying mantle exhibits low seismic velocities around 7.8 km/s suggesting some hydrothermal alterations or alteration of the upper mantle through faults generated by the flexure of the subducting plate as it enters the subduction. Low velocities, up to 4.5 km/s, associated with the accretionary wedge are well imaged from the trench back to the Nanao forearc. A major result concerns the abrupt termination of the buttress at the rear of the accretionary wedge. Despite the low resolution of the tomographic inversion near the subduction interface, several lines of evidence supporting the presence of a low velocity zone beneath the toe of the forearc buttress could be established. The Moho beneath the Ryukyu non-volcanic arc is located at a depth around 25 km depth.

  2. "Are You Sure You Know What You Are Doing?"--The Lived Experiences of an African American Male Kindergarten Teacher

    ERIC Educational Resources Information Center

    Bryan, Nathaniel; Browder, Jamison K.

    2013-01-01

    As of 2012, data indicate that only one percent of public school teachers are African American males. Numerous reports urge decision makers and higher education professionals to aggressively recruit and retain African American males as teachers in an effort to improve the academic outcomes of African American children in our educational system…

  3. Lower crustal deformation beneath the central Transverse Ranges, southern California: Results from the Los Angeles Region Seismic Experiment

    USGS Publications Warehouse

    Godfrey, N.J.; Fuis, G.S.; Langenheim, V.; Okaya, D.A.

    2002-01-01

    We present a P wave velocity model derived from active source seismic data collected during the 1994 Los Angeles Region Seismic Experiment. Our model extends previously published upper crustal velocity models to mantle depths. Our model was developed by both ray tracing through a layered model and calculating travel times through a gridded model. It includes an 8-km-thick crustal root centered beneath the surface trace of the San Andreas fault, north of the highest topography in the San Gabriel Mountains. A simple mass balance calculation suggests that ???36 km of north-south shortening across the San Andreas fault in the central Transverse Ranges could have formed this root. If north-south compression began when the "Big Bend" in the San Andreas fault formed at ???5 Ma, 36 km of shortening implies a north-south contraction rate of ???7.1 mm/yr across the central Transverse Ranges. If, instead, north-south compression began when the Transverse Ranges formed at 3.4-3.9 Ma, 36 km of shortening implies a contraction rate of 9.2-10.6 mm/yr. North of the San Andreas fault, the Mojave Desert crust has a low-velocity (6.3 km/s) mid and lower crust and a 28-km-deep Moho. South of the San Andreas fault, beneath the Los Angeles and San Gabriel Valley basins, there is a fast (6.6-6.8 km/s), thick (10-12 km) lower crust with a 27-km-deep Moho. Farther south still, the lower crust of the Continental Borderland is fast (6.6-6.8 km/s) and thin (5 km) with a shallow (22 km deep) Moho.

  4. "She Told Them, Oh That Bitch Got AIDS": Experiences of Multilevel HIV/AIDS-Related Stigma Among African American Women Living with HIV/AIDS in the South.

    PubMed

    Fletcher, Faith; Ingram, Lucy Annang; Kerr, Jelani; Buchberg, Meredith; Bogdan-Lovis, Libby; Philpott-Jones, Sean

    2016-07-01

    African American women bear a disproportionate burden of HIV/AIDS in the United States. Although they constitute only 13% of the US population, African Americans account for nearly 65% of all new HIV infections among American women. In addition, this population suffers comparatively greater adverse health outcomes related to HIV status. African American women living with HIV in the South may be further burdened by HIV/AIDS stigma, which is comparatively more pronounced in this region. To further explore this burden, we used narrative data and the Social Ecological Model to explore how African American women living with HIV in the US South recount, conceptualize, and cope with HIV/AIDS stigma at interpersonal, community, and institutional levels. Our narrative analysis suggests that HIV-positive African American women living in the South are vulnerable to experiences of multilevel HIV stigma in various settings and contexts across multiple domains of life. Stigma subsequently complicated disclosure decisions and made it difficult for women to feel supported in particular social, professional and medical settings that are generally regarded as safe spaces for noninfected individuals. Findings suggest that the debilitating and compounded effect of multilevel HIV/AIDS stigma on HIV-positive African American women in the South warrants closer examination to tailor approaches that effectively address the unique needs of this population. PMID:27410498

  5. Successfully Educating Our African-American Students

    ERIC Educational Resources Information Center

    Moncree-Moffett, Kareem

    2013-01-01

    The purpose of this empirical study was to explore the lived experiences of African American retired female teachers who have prior experience with educating urban African American students in public schools. Also explored are the experiences of active African American female teachers of urban African American students and comparisons are…

  6. West African monsoon decadal variability and surface-related forcings: second West African Monsoon Modeling and Evaluation Project Experiment (WAMME II)

    NASA Astrophysics Data System (ADS)

    Xue, Yongkang; De Sales, Fernando; Lau, William K.-M.; Boone, Aaron; Kim, Kyu-Myong; Mechoso, Carlos R.; Wang, Guiling; Kucharski, Fred; Schiro, Kathleen; Hosaka, Masahiro; Li, Suosuo; Druyan, Leonard M.; Sanda, Ibrah Seidou; Thiaw, Wassila; Zeng, Ning; Comer, Ruth E.; Lim, Young-Kwon; Mahanama, Sarith; Song, Guoqiong; Gu, Yu; Hagos, Samson M.; Chin, Mian; Schubert, Siegfried; Dirmeyer, Paul; Ruby Leung, L.; Kalnay, Eugenia; Kitoh, Akio; Lu, Cheng-Hsuan; Mahowald, Natalie M.; Zhang, Zhengqiu

    2016-06-01

    The second West African Monsoon Modeling and Evaluation Project Experiment (WAMME II) is designed to improve understanding of the possible roles and feedbacks of sea surface temperature (SST), land use land cover change (LULCC), and aerosols forcings in the Sahel climate system at seasonal to decadal scales. The project's strategy is to apply prescribed observationally based anomaly forcing, i.e., "idealized but realistic" forcing, in simulations by climate models. The goal is to assess these forcings' effects in producing/amplifying seasonal and decadal climate variability in the Sahel between the 1950s and the 1980s, which is selected to characterize the great drought period of the last century. This is the first multi-model experiment specifically designed to simultaneously evaluate such relative contributions. The WAMME II models have consistently demonstrated that SST forcing is a major contributor to the twentieth century Sahel drought. Under the influence of the maximum possible SST forcing, the ensemble mean of WAMME II models can produce up to 60 % of the precipitation difference during the period. The present paper also addresses the role of SSTs in triggering and maintaining the Sahel drought. In this regard, the consensus of WAMME II models is that both Indian and Pacific Ocean SSTs greatly contributed to the drought, with the former producing an anomalous displacement of the Intertropical Convergence Zone before the WAM onset, and the latter mainly contributes to the summer WAM drought. The WAMME II models also show that the impact of LULCC forcing on the Sahel climate system is weaker than that of SST forcing, but still of first order magnitude. According to the results, under LULCC forcing the ensemble mean of WAMME II models can produces about 40 % of the precipitation difference between the 1980s and the 1950s. The role of land surface processes in responding to and amplifying the drought is also identified. The results suggest that catastrophic

  7. Neighborhood Characteristics and Expectations of Racially Discriminatory Experiences Among African American Adolescents.

    PubMed

    Witherspoon, Dawn P; Seaton, Eleanor K; Rivas-Drake, Deborah

    2016-09-01

    This study examined how youth's neighborhood characteristics informed their expectations of racial discrimination concurrently and longitudinally. Secondary analyses were conducted on data from Waves 1, 3, 4, 5, and 6 of the Maryland Adolescent Development in Context Study, which permitted the examination of neighborhood influences among a socioeconomically diverse sample of African American parents and adolescents (n = 863; Mage  = 12.29). Youth exposed to more neighborhood disadvantage in seventh grade reported more negative concurrent neighborhood perceptions, which, in turn, predicted greater expectations of racial discrimination in eighth grade; youth's expectations remained stable into adulthood. Thus, support was found for the mediating role of youth's subjective neighborhood perceptions in the longitudinal relation between neighborhood structure and expectations of racial discrimination. PMID:27684392

  8. The Experience of Sexual Risk Communication in African American Families Living With HIV.

    PubMed

    Cederbaum, Julie A

    2012-09-01

    Mother-daughter communication plays an influential role in adolescent development. The impact of maternal HIV infection on family communication is not clear. This study explores how living with HIV impacts sexual risk communication between mothers and daughters and whether maternal HIV status influences adolescent choices about engagement in HIV risk behaviors. Data were collected from 12 African American women and 10 of their adolescent daughters through focus groups. Both mothers and daughters shared information about issues that promoted and inhibited communication and engagement in risk behaviors. Findings show that HIV status served as a mechanism for behavioral change related to communication and risk engagement behaviors. Therefore, HIV-infected mothers should be supported in communicating values and expectations to their daughters. PMID:23144530

  9. The Experience of Sexual Risk Communication in African American Families Living With HIV

    PubMed Central

    Cederbaum, Julie A.

    2012-01-01

    Mother-daughter communication plays an influential role in adolescent development. The impact of maternal HIV infection on family communication is not clear. This study explores how living with HIV impacts sexual risk communication between mothers and daughters and whether maternal HIV status influences adolescent choices about engagement in HIV risk behaviors. Data were collected from 12 African American women and 10 of their adolescent daughters through focus groups. Both mothers and daughters shared information about issues that promoted and inhibited communication and engagement in risk behaviors. Findings show that HIV status served as a mechanism for behavioral change related to communication and risk engagement behaviors. Therefore, HIV-infected mothers should be supported in communicating values and expectations to their daughters. PMID:23144530

  10. Surviving oppression under the Rock: The intersection of New York’s drug, welfare, and educational polices in the lived experiences of low-income African-Americans

    PubMed Central

    Windsor, Liliane Cambraia; Dunlap, Eloise; Armour, Marilyn

    2012-01-01

    Drawing on standpoint and intersectionality theories, this study explores the degree to which interactions among New York State’s Rockefeller Drug Laws, educational and welfare policies have contributed to the maintenance of a culture of surveillance in which the lives of impoverished African Americans are overseen and influenced by oppressive policies and governmental institutions. Qualitative secondary analysis of longitudinal ethnographic data was conducted. Findings demonstrate multiple disadvantages that impoverished African American families struggling with substance use and/or sale experience. These disadvantages accumulated intergenerationally, in a snowball effect making it difficult for participants to maintain stable lives. Findings explored the tension between participants’ experiences with oppression and the multiple ways they either assimilated or resisted their oppression. New sensitive policies informed by standpoint, intersectionality, and Afrocentric perspectives must be developed to increase the availability of meaningful employment and strengthening impoverished African American communities. PMID:23216440

  11. Physical activity among African American and Latino middle school girls: consistent beliefs, expectations, and experiences across two sites.

    PubMed

    Taylor, W C; Yancey, A K; Leslie, J; Murray, N G; Cummings, S S; Sharkey, S A; Wert, C; James, J; Miles, O; McCarthy, W J

    1999-01-01

    Physical inactivity is a major public health concern. Low levels of physical activity are reported in many subgroups of women including adolescent girls. More data are needed to better understand factors related to physical activity participation in adolescent girls. Therefore, we explored adolescent girls' reasons for participating and not participating in physical activity. Two independent samples were taken in California and Texas; the total sample included thirty-four African American and Latino girls. Six focus groups were conducted by trained facilitators. Based on independent qualitative analyses, six replicated themes emerged from the focus groups. Fun, social support, and concern with body image facilitated participation in activity. In contrast, negative experiences in physical education classes, concerns about appearance after activity, and lack of opportunity impeded participation in activity. Overall, the girls showed an interest in physical activity and identified activity motivators and barriers. We discuss the implications of our findings for future research.

  12. Enduring consequences of early experiences: 40 year effects on survival and success among African elephants (Loxodonta africana).

    PubMed

    Lee, Phyllis C; Bussière, Luc F; Webber, C Elizabeth; Poole, Joyce H; Moss, Cynthia J

    2013-04-23

    Growth from conception to reproductive onset in African elephants (Loxodonta africana) provides insights into phenotypic plasticity, individual adaptive plastic responses and facultative maternal investment. Using growth for 867 and life histories for 2652 elephants over 40 years, we demonstrate that maternal inexperience plus drought in early life result in reduced growth rates for sons and higher mortality for both sexes. Slow growth during early lactation was associated with smaller adult size, later age at first reproduction, reduced lifetime survival and consequently limited reproductive output. These enduring effects of trading slow early growth against immediate survival were apparent over the very long term; delayed downstream consequences were unexpected for a species with a maximum longevity of 70+ years and unpredictable environmental experiences.

  13. Traditional Healing, Biomedicine and the Treatment of HIV/AIDS: Contrasting South African and Native American Experiences

    PubMed Central

    Flint, Adrian

    2015-01-01

    Traditional healing remains an important aspect of many people’s engagement with healthcare and, in this, responses to the treatment of HIV/AIDS are no different. However, given the gravity of the global HIV/AIDS pandemic, there has been much debate as to the value of traditional healing in this respect. Accordingly, this paper explores the extent to which meaningful accommodation between the biomedical and traditional sectors is possible (and/or even desirable). It does this through a consideration of Native American and South African experiences, looking at how the respective groups, in which medical pluralism is common, have addressed the issue of HIV/AIDS. The paper points to the importance of developing “culturally appropriate” forms of treatment that emphasise complementary rather than adversarial engagement between the traditional and biomedical systems and how policymakers can best facilitate this. PMID:25903057

  14. Traditional healing, biomedicine and the treatment of HIV/AIDS: contrasting south african and native American experiences.

    PubMed

    Flint, Adrian

    2015-04-20

    Traditional healing remains an important aspect of many people's engagement with healthcare and, in this, responses to the treatment of HIV/AIDS are no different. However, given the gravity of the global HIV/AIDS pandemic, there has been much debate as to the value of traditional healing in this respect. Accordingly, this paper explores the extent to which meaningful accommodation between the biomedical and traditional sectors is possible (and/or even desirable). It does this through a consideration of Native American and South African experiences, looking at how the respective groups, in which medical pluralism is common, have addressed the issue of HIV/AIDS. The paper points to the importance of developing "culturally appropriate" forms of treatment that emphasise complementary rather than adversarial engagement between the traditional and biomedical systems and how policymakers can best facilitate this.

  15. Undergraduate African American females in the sciences: A qualitative study of student experiences affecting academic success and persistence

    NASA Astrophysics Data System (ADS)

    Essien-Wood, Idara R.

    Given the lack of literature on Undergraduate African American females in the sciences (UAAFS), this study sought to explicate their experiences at one large, predominantly White, Research I institution in the southwestern United States. In particular, the purpose of this study was to identify factors that affect the academic success and persistence of Black females in the natural and physical sciences. Data was collected via in-depth, semi-structured interviews with 15 Black female science majors. Findings from this study identified several supportive mechanisms for academic success: family, religion, teaching assistants and friends. Also identified were seven barriers to academic success: employment, lack of diversity, cultural dissonance, unwelcoming Research I environment, faculty, advisors, classmates, and lab groups. Further, an analysis of students' responses revealed numerous instances of racial and gender micro-aggressions. Recommendations are provided to address factors identified as affecting student academic success and persistence as well as a culture of micro-aggressive behavior.

  16. Assessment of P and S wave energy radiated from very small shear-tensile seismic events in a deep South African mine

    NASA Astrophysics Data System (ADS)

    Kwiatek, Grzegorz; Ben-Zion, Yehuda

    2013-07-01

    We discuss requirements for reliable estimates of radiated seismic energy in S and P phases and derive ratios of S-to-P radiated energy (ES/EP) of 539 seismic events with local magnitudes - 5.23 ≤ ML ≤ - 2.41 (subdecimeter size) recorded by high-frequency acoustic emission (AE) sensors of the JAGUARS seismic network in the Mponeng deep gold mine, South Africa. The analyzed events are aftershocks of a MW1.9 earthquake, and the recording AE sensors are located within about 40 m of the events. A shear-tensile model is used to simulate the radiation pattern of P and S phases from a family of rupture models ranging from pure shear to pure tensile failure. The calculations include correction factors for energy estimates associated with given source-receiver geometries and expected focal mechanism with possible tensile component. Synthetic calculations are used to assess the effects of limited observed frequency band and attenuation on the estimated ES/EP ratios. The model calculations provide guidelines on when different approximations may be used. The obtained ES/EP ratios for the analyzed events are relatively low (median value < 5) for the full range of model parameters tested, suggesting that significant number of the events display a tensile component. Events with very small ratios (e.g., <1) may reflect enhanced P radiation associated with rock damage in the source volumes.

  17. How astronauts would conduct a seismic experiment on the planet Mars

    NASA Astrophysics Data System (ADS)

    Pletser, V.; Lognonne, P.; Dehant, V.

    During the Summer 2001 Flashline Mars Arctic Research Station (M.A.R.S.) campaign in Devon Island, Nunavut, Canada, the crew of the second rotation conducted a geophysics experiment aiming at assessing the feasibility of an active seismology method to detect subsurface water on Mars. A crew of three deployed a line of 24 sensors. Reflected and refracted signals produced by mini-quakes generated by a sledge hammer were recorded by a seismograph. The experiment was conducted three times, once in a dry run and twice during simulated Extra-Vehicular Activities (EVA) on the edge of the Haughton crater, allowing a three dimensional characterization of the subsurface ground to a depth of several hundred meters. Data were recorded for later detailed processing. A third EVA attempt inside the crater had to be aborted because of the poor weather and terrain conditions. Despite this failed attempt, a large amount of results were collected. Several operational lessons were learned from conducting this experiment under simulated EVA conditions. This paper presents the experiment and the methodology used, reviews the experiment performance and summarizes the results obtained and the operational lessons learned.

  18. "We're Here Because We're Black": The Schooling Experiences of French-Speaking African-Canadian Students with Refugee Backgrounds

    ERIC Educational Resources Information Center

    Schroeter, Sara; James, Carl E.

    2015-01-01

    This article discusses the educational experiences of a group of French-speaking Black African-born students who entered Canada as refugees. They were attending a French school and were placed in a separate programme that was designed to meet their particular needs given their limited language skills and level of education. Drawing on critical…

  19. Low-Income African-American Caregivers' Experiences of Being Referred to Mental Health Services by the School Counselor: Implications for Best Practices

    ERIC Educational Resources Information Center

    Tucker, Catherine

    2009-01-01

    Referring students for mental health care is a core job function for school counselors, and one that is often stressful for all parties involved. In this phenomenological study, six low-income African-American caregivers were interviewed about their experiences of having a son or grandson referred for mental health care by the school counselor.…

  20. The Role of Race, Racism and Power in the Experiences and Perspectives of African American Males in the Context of Their Ascendence to the Superintendency

    ERIC Educational Resources Information Center

    George, Hughes B.

    2011-01-01

    Using the lens of Critical Race Theory, I present the experiences and perspectives of African American male superintendents in the context of their ascension to the superintendency. Participants in the study are chief executive officers of a school district. The primary question of this study is what are the contributing factors, particularly the…

  1. An integrated petrophysical approach to the sub-basalt imaging problem using well logging data to link measurements from cores and seismic experiments

    NASA Astrophysics Data System (ADS)

    Waagstein, R.; Boldreel, L. O.; Andersen, C.

    2003-04-01

    Flood basalt covered basins exist world wide along continental margins and are increasingly coming into the focus of the hydrocarbon industry as more accessible fields are being depleted. However, it has proved difficult in many places to look through the basalt cover by conventional seismic reflection methods. This stresses the need for a better understanding of the acoustic properties of basalt. The Seismic Faroes Basalt Project (SeiFaBa) was established in 2002 as an integrated study of the sub-basalt image problem. It involves 9 scientific institutions and individuals and is funded collectively by all oil companies operating in the Faroes sector (the Sindri group). The planned fieldwork includes core drilling, wire-line logging, multi-azimuth VSP and surface seismic experiments at land and sea. It is mainly centred around Glyvursnes, a relatively flat promontory near Tórshavn that allows optimal layout of seismic lines and integration of core, log and seismic data. We present the initial task of drilling and logging, which was performed in Oct.-Nov. 2002. A 700 m slim borehole was drilled on the shore of Glyvursnes with wire-line coring technique and an old 660 m borehole (Vestmanna-1) 30 km farther northwest partly blocked by calcite fillings was reopened using the same equipment. An extensive wire-line logging program was subsequently run in both holes. These two holes, together with the existing 3.65-km Lopra-1/1A hole in the southernmost island Suduroy, cover all three Faroes basalt formations and a range of lava compositions and morphologies. We show examples of the correlation of lava flow sequences and wire-logging measurements. Detailed analysis of the new logs is being planned together with laboratory studies of the petrography, rock chemistry and petrophysical properties of core samples with the aim of establishing a log stratigraphy and scale core data to seismic scales.

  2. The Subjective Experience of Social Class and Upward Mobility Among African American Men in Graduate School.

    PubMed

    Sánchez, Francisco J; Liu, William Ming; Leathers, Leslie; Goins, Joyce; Vilain, Eric

    2011-10-01

    We used Consensual Qualitative Research Methodology to analyze responses from 14 African American men (Mdn(Age) = 25 years-old) in graduate school at a predominantly-White university in the Midwestern region of the United Sates regarding how they acquired awareness of their social-class status; how social class was related to their sense of masculinity; how social class was related to race and skin tone; and the role that education and a romantic partner could play in upward mobility. School peers were the main source for their early awareness of social class. Many believed that discrimination maintains social class stratification that disadvantages racial minorities and that one's race will always trump any personal characteristics-including having light-complected skin and an advanced degree. Finally many overcame several obstacles during their educational career, and most believed that a romantic relationship with a woman from a privileged background could facilitate upward mobility. Psychological scientists and practitioners are encouraged to consider the role that social class plays when examining men's well-being.

  3. The Subjective Experience of Social Class and Upward Mobility Among African American Men in Graduate School

    PubMed Central

    Sánchez, Francisco J.; Liu, William Ming; Leathers, Leslie; Goins, Joyce; Vilain, Eric

    2011-01-01

    We used Consensual Qualitative Research Methodology to analyze responses from 14 African American men (MdnAge = 25 years-old) in graduate school at a predominantly-White university in the Midwestern region of the United Sates regarding how they acquired awareness of their social-class status; how social class was related to their sense of masculinity; how social class was related to race and skin tone; and the role that education and a romantic partner could play in upward mobility. School peers were the main source for their early awareness of social class. Many believed that discrimination maintains social class stratification that disadvantages racial minorities and that one's race will always trump any personal characteristics—including having light-complected skin and an advanced degree. Finally many overcame several obstacles during their educational career, and most believed that a romantic relationship with a woman from a privileged background could facilitate upward mobility. Psychological scientists and practitioners are encouraged to consider the role that social class plays when examining men's well-being. PMID:22058659

  4. South African experience with asbestos related environmental mesothelioma: is asbestos fiber type important?

    PubMed

    White, Neil; Nelson, Gill; Murray, Jill

    2008-10-01

    South Africa (SA), a country in which all three commercially important asbestos minerals have been mined and milled, has retained proven cases of mesothelioma linked with environmental exposure to asbestos. This study illustrates the importance of fiber type in the occurrence of environmental mesothelioma. Four studies have reviewed the source of occupational or environmental asbestos exposure in 504 histologically proven cases of mesothelioma in South Africa. One hundred and eighteen cases (23%) were thought to be related to environmental exposure to asbestos. In the vast majority of these cases, exposure was linked to crocidolite mining activities in the Northern Cape Province. Two cases were thought to have occurred in relation to amosite and Transvaal crocidolite exposure in the Limpopo Province. In the balance of cases there was some uncertainty. No cases were reported with exposure to South African chrysotile. Consequently, in the vast majority of cases of mesothelioma, environmental exposure to asbestos occurred in the Northern Cape Province, in proximity to mines, mills and dumps where crocidolite was processed. Crocidolite appears to be far more mesotheliomagenic than amosite, and chrysotile has not been implicated in the disease. This is true for both occupationally and environmentally exposed individuals.

  5. Factors affecting student success in a first-year mathematics course: a South African experience

    NASA Astrophysics Data System (ADS)

    Kizito, Rita; Munyakazi, Justin; Basuayi, Clement

    2016-01-01

    In spite of sustained efforts tertiary institutions implement to try and improve student academic performance, the number of students succeeding in first-year mathematics courses remains disturbingly low. For most students, the gap between their mathematical capability and the competencies they are expected and need to develop to function effectively in these courses persists even after course instruction. In this study, an instrument for identifying and examining factors affecting student performance and success in a first-year Mathematics university course was developed and administered to 86 students. The overall Cronbach's Alpha coefficient for the questionnaire was found to be 0.916. Having identified variables from prior research known to affect student performance, factor analysis was used to identify variables exhibiting the greatest impact on student performance. The variables included prior academic knowledge, workload, student approaches to learning, assessment, student support teaching quality, methods and resources. From the analysis, students' perceptions of their workload emerged as the factor having the greatest impact on student's performance, followed by the matriculation examination score. The findings are discussed and strategies that can be used to improve teaching and contribute to student success in a first-year mathematics course in a South African context are presented.

  6. High-pressure dehydration experiments of antigorite-olivine samples to explain seismicity in the lower Benioff plane

    NASA Astrophysics Data System (ADS)

    Ferrand, T. P.; Hilairet, N.; Incel, S.; Gasc, J.; Labrousse, L.; Renner, J.; Wang, Y.; Schubnel, A.

    2015-12-01

    Here we show the first recording of acoustic emissions due to serpentine dehydration in partially serpentinized sintered peridotites deformed in pressure and temperature conditions representative for intermediate depths earthquakes. Experiments were conducted in a D-DIA apparatus using simultaneously X-ray diffraction and acoustic emission monitoring, to estimate both stress-strain relationship and occurrence of micro-earthquakes. We use sintered powders of San Carlos olivine and Corsica antigorite, which is the HT serpentine polymorph. Our results demonstrate that around 2 GPa, serpentinized peridotite with serpentine content of 5% has a seismogenic potential. In the same conditions, no acoustic emission is detected in melanges with larger serpentine content (20%). At higher pressure (3.5 GPa) acoustic emissions are observed for melanges with up to 20% serpentine. Serpentine contents may favor initiation of mechanical failure of the olivine "load bearing" network for contents lower than a threshold value, at which connection of the weak phase (serpentine) prevents from stress rise in the stronger matrix (olivine). This threshold seems to increase with pressure. Thus mechanical instability may originate in serpentine dehydration for part of the intermediate-depth earthquakes, and hence at least part of the lower Benioff zone seismicity. Serpentine dehydration would act as a triggering mechanism for earthquakes nucleating and propagating in the olivine network.

  7. Notes on some experiments on the application of subtractive compensation to USGS seismic magnetic tape recording and playback systems

    USGS Publications Warehouse

    Eaton, Jerry P.

    1975-01-01

    The purpose of these experiments is to lay the groundwork for the implementation of subtractive compensation of the USGS seismic network tape playbacks utilizing the Develco model 6203 discriminators at a x1 playback speed. Although the Develco discriminators were designed for this application and a matching Develco compensation discriminator was purchased, effective use of this system for subtractive compensation has been blocked by the inadequate (frequency dependent) matching of the phase of the compensation signal to that of the data signal at the point compensation is carried out in the data discriminators. John Van Schaack has ameliorated the phase mismatch problem by an empirical alteration of the compensation discriminator input bandpass filter. We have selected a set (of eight) Develco discriminators and adjusted their compensation signal input levels to minimize spurious signals (noise) originating from tape speed irregularities. The sensitivity of the data discriminators was adjusted so that deviations of +125 Hz and -125 Hz produced output signals of +2.00 volts and -2.00 volts, respectively. The eight data discriminators are driven by a multiplex signal on a single tape track (subcarriers 680, 1020, 1360, 1700, 2040, 2380, 2720, and 3060 Hz). The Develco-supplied compensation discriminator requires an unmodulated 3125 Hz signal on a separate tape track.

  8. Mining-Induced Stress Transfer and Its Relation to a {M}_w 1.9 Seismic Event in an Ultra-deep South African Gold Mine

    NASA Astrophysics Data System (ADS)

    Ziegler, Moritz; Reiter, Karsten; Heidbach, Oliver; Zang, Arno; Kwiatek, Grzegorz; Stromeyer, Dietrich; Dahm, Torsten; Dresen, Georg; Hofmann, Gerhard

    2015-10-01

    On 27 December 2007, a {M}_w 1.9 seismic event occurred within a dyke in the deep-level Mponeng Gold Mine, South Africa. From the seismological network of the mine and the one from the Japanese-German Underground Acoustic Emission Research in South Africa (JAGUARS) group, the hypocentral depth (3,509 m), focal mechanism and aftershock location were estimated. Since no mining activity took place in the days before the event, dynamic triggering due to blasting can be ruled out as the cause. To investigate the hypothesis that stress transfer, due to excavation of the gold reef, induced the event, we set up a small-scale (450× 300× 310{m}^3) high-resolution three-dimensional (3D) geomechanical numerical model. The model consisted of the four different rock units present in the mine: quartzite (footwall), hard lava (hanging wall), conglomerate (gold reef) and diorite (dykes). The numerical solution was computed using a finite-element method with a discretised mesh of approximately 10^6 elements. The initial stress state of the model is in agreement with in situ data from a neighbouring mine, and the step-wise excavation was simulated by mass removal from the gold reef. The resulting 3D stress tensor and its changes due to mining were analysed based on the Coulomb failure stress changes on the fault plane of the event. The results show that the seismic event was induced regardless of how the Coulomb failure stress changes were calculated and of the uncertainties in the fault plane solution. We also used the model to assess the seismic hazard due to the excavation towards the dyke. The resulting curve of stress changes shows a significant increase in the last {˜}50 {m} in front of the dyke, indicating that small changes in the mining progress towards the dyke have a substantial impact on the stress transfer.

  9. Site Characterization of the Source Physics Experiment Phase II Location Using Seismic Reflection Data

    SciTech Connect

    Sexton, Emily; Snelson, Catherine M; Chipman, Veraun D; Emer, Dudley; White, Bob; Emmit, Ryan; Wright, Al; Drellack, Sigmund; Huckins-Gang, Heather; Mercadante, Jennifer; Floyd, Michael; McGowin, Chris; Cothrun, Chris; Bonal, Nedra

    2013-12-05

    An objective of the Source Physics Experiment (SPE) is to identify low-yield nuclear explosions from a regional distance. Low-yield nuclear explosions can often be difficult to discriminate among the clutter of natural and man-made explosive events (e.g., earthquakes and mine blasts). The SPE is broken into three phases. Phase I has provided the first of the physics-based data to test the empirical models that have been used to discriminate nuclear events. The Phase I series of tests were placed within a highly fractured granite body. The evolution of the project has led to development of Phase II, to be placed within the opposite end member of geology, an alluvium environment, thereby increasing the database of waveforms to build upon in the discrimination models. Both the granite and alluvium sites have hosted nearby nuclear tests, which provide comparisons for the chemical test data. Phase III of the SPE is yet to be determined.

  10. Tackling the African “poverty trap”: The Ijebu-Ode experiment

    PubMed Central

    Mabogunje, Akin L.

    2007-01-01

    An experiment in poverty reduction began in 1998 in the city of Ijebu-Ode, Nigeria (estimated 1999 population 163,000), where, without the remittances from relatives abroad, an estimated 90% of the population lived below the poverty line of $1.00 (U.S.) per person per day. Central to the experiment was whether poverty can be dramatically reduced through a city consultation process that seeks to mobilize the entire community along with its diaspora. With 7 years of experience, the Ijebu-Ode experiment has been successful in many ways. There is increasing evidence that poverty in the city has been reduced significantly through the microfinancing of existing and new productive activities and the estimated >8,000 jobs these activities have created. Training based on both sustainability science and technology and indigenous practitioner knowledge has been a critical factor in the establishment of cooperatives and the development of new enterprises in specialty crops, small animal, and fish production. Much of this success has been possible as a result of harnessing social capital, especially through the dynamic leadership of the traditional authorities of the city and by the provision of ample loanable funds through the National Poverty Eradication Program of the federal government. The city consultation process itself engendered a participatory focus to the experiment from the beginning and has encouraged sustainabaility. Yet long-term sustainability is still in question as the initial leadership needs replacement, and credit, the heart of the experiment, lacks sufficient collateral. PMID:17942687

  11. Religion and Spirituality in the Meaning-Making and Coping Experiences of African American Women: A Qualitative Analysis

    ERIC Educational Resources Information Center

    Mattis, Jacqueline S.

    2002-01-01

    This qualitative study examines the ways in which African American women use religion/spirituality to cope and to construct meaning in times of adversity. Content analysis of the narratives of a sample of African American women respondents (n = 23) revealed a set of eight nonoverlapping themes that explicate religiosity/spirituality's role in…

  12. Experiences of Reentry and Nontraditional African American Women and Their Support Networks: A Journey in Pursuit of a College Degree

    ERIC Educational Resources Information Center

    Denson, Janet L.

    2010-01-01

    This research study reports the findings of how support networks impact the success of African American women in completing their college degree. A phenomenological research methodology of 10 African American women participants of in-depth face-to-face interviews was used to collect the data. Fifty percent of the women completed their degree and…

  13. Understanding the Relationships and Experiences That Contribute to African Americans' Decision to Enroll in Doctoral Education

    ERIC Educational Resources Information Center

    McCallum, Carmen Michelle

    2012-01-01

    African Americans have made great advancements in postsecondary education. Over the last thirty years, enrollment and degree attainment has increased over 65% at undergraduate and graduate degree levels (National Center for Education Statistics, 2008). Yet despite these gains, African Americans continue to severely trail behind other racial and…

  14. A Grounded Theory of the College Experiences of African American Males in Black Greek-Letter Organizations

    ERIC Educational Resources Information Center

    Ford, David Julius, Jr.

    2014-01-01

    Studies have shown that involvement in a student organization can improve the academic and psychosocial outcomes of African American male students (Harper, 2006b; Robertson & Mason, 2008; Williams & Justice, 2010). Further, Harper, Byars, and Jelke (2005) stated that African American fraternities and sororities (i.e., Black Greek-letter…

  15. Cultural Self Meets Cultural Other in the African American Experience: Teachers' Responses to a Curriculum Content Reform.

    ERIC Educational Resources Information Center

    Shujaa, Mwalimu J.

    1995-01-01

    Discusses certain complexities of personal transformation among people implementing African and African American curriculum content reform in the Buffalo (New York) public schools, highlighting individual teachers' understanding of and responses to the reform and noting that attitudes about their own and other people's ethnicity proved important…

  16. Crustal structure variations along the NW-African continental margin: a comparison of new and existing models from wide angle and reflection seismic data

    NASA Astrophysics Data System (ADS)

    Biari, Y.; Klingelhoefer, F.; Sahabi, M.; Aslanian, D.; Philippe, S.; Louden, K. E.; Berglar, K.; Moulin, M.; Mehdi, K.; Graindorge, D.; Evain, M.; Benabellouahed, M.; Reichert, C. J.

    2014-12-01

    Deep seismic data represent a key to understand the geometry and mechanism of continental rifting. The passive continental margin of NW-Africa is one of the oldest on earth, formed during the Upper Triassic-Lower Liassic rifting of the central Atlantic Ocean over 200 Ma. We present new and existing wide-angle and reflection seismic data from three study regions along the margin located in the North Moroccan salt basin, on the central continental margin offshore Safi and in the south, offshore Dakhla. In each of the study areas several combined wide-angle and reflection seismic profiles perpendicular and parallel to the margin have been acquired and forward modelled using comparable methods. The thickness of unthinned continental crust decreases from 36 km in the North to about 27 km in the South. In the North Moroccan Basin continental crust thins from originally 36 km to about 8 km in a 150 km wide zone. The basin itself is underlain by highly thinned continental crust. Offshore safi thinning of the continental crust is confined to a 130 km wide zone with no neighboring sedimentary basin underlain by continental crust. In both areas the zone of crustal thinning is characterised by the presence of large blocks and abundant salt diapirs. In the south crustal thinning is more rapid in a zone of 90 km and asymmetric with the upper crust thinning more closely to the continent than the lower crust, probably due to depth-dependent stretching and the presence of the precambrian Reguibat Ridge on land. Oceanic crust is characterised by a thickness of 7-8 km along the complete margin. Relatively high velocities of up to 7.5 km/s have been imaged between magnetic anomalies S1 and M25, and are probably related to changes in the spreading velocities at the time of the Kimmeridgian/Tithonian plate reorganisation. Volcanic activity seems to be confined to the region next to the Canary Islands, and is thus not related to the initial opening of the oceanic, which was related to no

  17. Behind the Miracle: Emerging Insights from South African Business Leadership Experiences

    ERIC Educational Resources Information Center

    Lynham, Susan A.; Taylor, Robert K.; Dooley, Larry M.

    2005-01-01

    The decade preceding the end of apartheid in South Africa (SA) represents a period of remarkable national leadership, and atypical business leadership. Insights from these extraordinary business leadership experiences largely remain in the form of uncaptured oral histories. Yet they are inspiring stories of practices and principles of truly…

  18. Predicting Substance Use Behavior among South African Adolescents: The Role of Leisure Experiences across Time

    ERIC Educational Resources Information Center

    Sharp, Erin Hiley; Coffman, Donna L.; Caldwell, Linda L.; Smith, Edward A.; Wegner, Lisa; Vergnani, Tania; Mathews, Catherine

    2011-01-01

    Using seven waves of data, collected twice a year from the 8th through the 11th grades in a low-resource community in Cape Town, South Africa, we aimed to describe the developmental trends in three specific leisure experiences (leisure boredom, new leisure interests, and healthy leisure) and substance use (cigarettes, alcohol, and marijuana)…

  19. Examining the Cultural Adjustment Experiences of African International College Students: A Qualitative Analysis

    ERIC Educational Resources Information Center

    Constantine, Madonna G.; Anderson, Gregory M.; Berkel, LaVerne A.; Caldwell, Leon D.; Utsey, Shawn O.

    2005-01-01

    The authors examined the cultural adjustment experiences of 12 Kenyan, Nigerian, and Ghanaian international college students through semistructured interviews. Using consensual qualitative research methodology (C. E. Hill, B. J. Thompson, & E. N. Williams, 1997), 7 primary domains or themes related to these students' cultural adjustment…

  20. Life Experience of African Graduate Students in a Multi-Cultural Setting: A Case Study.

    ERIC Educational Resources Information Center

    Antwi, Ransford; Ziyati, Abdelali

    A study examined how international students from North and West Africa fit in, cope, manage, and respond to their experiences in American Universities that are in many cases set up in the context of Americans who constitute the majority. Assuming that the lives of international students outside their home countries and cultures are…

  1. Testing Models of Magmatic and Hydrothermal Segmentation: A Three-Dimensional Seismic Tomography Experiment at the Endeavour Ridge (Invited)

    NASA Astrophysics Data System (ADS)

    Wilcock, W. S.; Toomey, D. R.; Hooft, E. E.; Weekly, R. T.; Wells, A. E.

    2010-12-01

    Competing models for what controls the segmentation and intensity of ridge crest processes are at odds on the scale of mantle and crustal magmatic segmentation, the distribution of hydrothermal venting with respect to a volcanic segment and the properties of the thermal boundary layer that transports energy between the magmatic and hydrothermal systems. The presence of an axial magma chamber (AMC) reflector beneath the central portion of the Endeavour segment of the Juan de Fuca ridge, as well as systematic along axis changes in seafloor depth, ridge crest morphology and hydrothermal venting provide an ideal target for testing conflicting hypotheses. In late summer 2009, we conducted an active source seismic experiment on the Endeavour segment of the Juan de Fuca Ridge. A total of 5,567 airgun shots from the 36-gun, 6,600 in3 airgun array of the R/V Marcus G. Langseth were recorded by 68 short-period ocean bottom seismometers (OBSs) deployed at 64 sites. The experimental geometry utilized 3 nested scales and was designed to image (1) crustal thickness variations within 25 km of the axial high (0 to 900 kyr); (2) the map view heterogeneity and anisotropy of the topmost mantle beneath the spreading axis; (3) the three-dimensional structure of the crustal magmatic system and (4) the detailed three-dimensional, shallow crustal thermal structure beneath the Endeavour vent fields. At the segment scale, six 100-km-long ridge-parallel shot lines were obtained at distances of 16, 23 and 30 km to both sides of the ridge axis with OBSs on all but the outer lines. At the along-axis scale of the AMC reflector, shot lines are spaced 1 km apart and OBSs 8 km apart within a 60 x 20 km2 region. At the vent field scale, shots were obtained on a 500 x 500 m2 grid and OBSs spaced 5 km apart within a 20 x 10 km2 region. All the shooting lines were collected with a 9 m source depth to obtain impulsive arrivals at shorter ranges but the outer lines were also shot with a 15 m source depth

  2. Seafloor surface processes and subsurface paleo-channel unconformities mapped using multi-channel seismic and multi-beam sonar data from the Galicia 3D seismic experiment.

    NASA Astrophysics Data System (ADS)

    Gibson, J. C.; Shillington, D. J.; Sawyer, D. S.; Jordan, B.; Morgan, J. K.; Ranero, C.; Reston, T. J.

    2015-12-01

    In this study we use geophysical methods, stratigraphic relationships, and coring/drilling leg results to assess possible controls on deep-sea channel formation in order to further constrain paleo-channel (PC) and associated unconformity timing/source processes. A series of cut and fill PC are mapped in 3D multi-channel seismic (MCS) data and compared with multi-beam (MB) sonar bathymetry/backscatter data collected during the Galicia 3D survey with the R/V Marcus G. Langseth (2013). The MCS data were collected using four 6 km streamers spaced at 200 m resulting in 25 m x 25 m common mid-point bins within the ~67 km x 20 km 3D volume. The MB data were collected at an average depth of ~4900 m with a constrained swath width of 4.5 km resulting in 11.25x overlap while enabling 25-m bathymetry and 10-m backscatter grids. The PC lie below the mouth of a submarine canyon at the edge of the Galicia abyssal plain and cut pre/syn-rift sediments; they are bound by a rift block to the north and paleo-levees to the south (maximum height of ~180m). From drilling results, the most recent PC is late Miocene in age. In this study, four PC are traced into the basin as unconformities. Several of the PC/unconformities are tentatively correlated with previously interpreted Pyrenean orogeny/compressional Miocene/Oligocene tectonic events. However, one PC/unconformity within this interval has not been previously interpreted. In order test the hypothesis that the unconformities are the result of a significant change in base level indicated by a low shale/sand (SS) ratio, we use seismic surface attributes to calculate the SS ratio and trace the horizontal extent of the unconformities. Additionally, the MB/MCS seafloor morphology reveals sedimentary waves outboard of the canyon mouth. We use backscatter data to compare the extent of recent processes (e.g., Pleistocene glaciation/de-glaciation) with the unconformities by mapping the surface/shallow subsurface SS ratio (volume scattering).

  3. Using diaries to explore the work experiences of primary health care nursing managers in two South African provinces

    PubMed Central

    Munyewende, Pascalia O.; Rispel, Laetitia C.

    2014-01-01

    Background South Africa is on the brink of another wave of major health system reforms that underscore the centrality of primary health care (PHC). Nursing managers will play a critical role in these reforms. Objective The aim of the study was to explore the work experiences of PHC clinic nursing managers through the use of reflective diaries, a method hitherto under-utilised in health systems research in low- and middle-income countries. Design During 2012, a sub-set of 22 PHC nursing managers was selected randomly from a larger nurses’ survey in two South African provinces. After informed consent, participants were requested to keep individual diaries for a period of 6 weeks, using a clear set of diary entry guidelines. Reminders consisted of weekly short message service reminders and telephone calls. Diary entries were analysed using thematic content analysis. A diary feedback meeting was held with all the participants to validate the findings. Results Fifteen diaries were received, representing a 68% response rate. The majority of respondents (14/15) were female, each with between 5 and 15 years of nursing experience. Most participants made their diary entries at home. Diaries proved to be cathartic for individual nursing managers. Although inter-related and not mutually exclusive, the main themes that emerged from the diary analysis were health system deficiencies; human resource challenges; unsupportive management environment; leadership and governance; and the emotional impact of clinic management. Conclusions Diaries are an innovative method of capturing the work experiences of managers at the PHC level, as they allow for confidentiality and anonymity, often not possible with other qualitative research methods. The expressed concerns of nursing managers must be addressed to ensure the success of South Africa's health sector reforms, particularly at the PHC level. PMID:25537937

  4. Seismic moment tensors of acoustic emissions recorded during laboratory rock deformation experiments: sensitivity to attenuation and anisotropy

    NASA Astrophysics Data System (ADS)

    Stierle, Eva; Vavryčuk, Václav; Kwiatek, Grzegorz; Charalampidou, Elli-Maria; Bohnhoff, Marco

    2016-04-01

    Seismic moment tensors can provide information on the size and orientation of fractures producing acoustic emissions (AEs) and on the stress conditions in the sample. The moment tensor inversion of AEs is, however, a demanding procedure requiring carefully calibrated sensors and accurate knowledge of the velocity model. In field observations, the velocity model is usually isotropic and time independent. In laboratory experiments, the velocity is often anisotropic and time dependent and attenuation might be significant due to opening or closure of microcracks in the sample during loading. In this paper, we study the sensitivity of the moment tensor inversion to anisotropy of P-wave velocities and attenuation. We show that retrieved moment tensors critically depend on anisotropy and attenuation and their neglect can lead to misinterpretations of the source mechanisms. The accuracy of the inversion also depends on the fracturing mode of AEs: tensile events are more sensitive to P-wave anisotropy and attenuation than shear events. We show that geometry of faulting in anisotropic rocks should be studied using the source tensors, since the P- and T-axes of the moment tensors are affected by velocity anisotropy and deviate from the true orientation of faulting. The stronger the anisotropy is, the larger the deviations are. Finally, we prove that the moment tensor inversion applied to a large dataset of AEs can be utilized to provide information on the attenuation parameters of the rock sample. The method is capable of measuring anisotropic attenuation in the sample and allows for detection of dilatant cracking according to the stress regime.

  5. 1978 Yellowstone-eastern Snake River Plain seismic profiling experiment: Data and upper crustal structure of the Yellowstone region

    SciTech Connect

    Schilly, M.M.; Smith, R.B.; Braile, L.W.; Ansorge, J.

    1982-04-10

    Eleven in-line refraction profiles, recorded to distances of 300 km, and one azimuthal fan plot were constructed from data recorded with a 150-station array in the Yellowstone National Park area during the 1978 Yellowstone-Snake River Plain seismic experiment. Interpretations of the data suggest that the crustal P wave velocity model for the Yellowstone region is characterized by (1) an averaged 10-km-thick upper crustal layer, V/sub p/ = 6.0 km/s, (2) an average crustal velocity of 6.3 km/s, and (3) a total crustal thickness of 44 km. Velocity models are presented for profiles that emphasize the upper crust and show (1) a decrease in the depth to the top of the upper crustal crystalline basement from 5 km in southwestern Yellowstone near Island Park to 1 km at the northeast side of the Yellowstone Plateau that is interpreted as a progressive thinning of the silicic surface volcanic layer to the northeast and (2) evidence for a large lateral inhomogeneity interpreted to be a low-velocity body, with a decrease of at least 10% in P wave velocity, located beneath the northeast corner of the Yellowstone Plateau. The low-velocity zone coincides with a local -30-mgal residual gravity anomaly and is located beneath part of the Sour Creek resurgent dome and part of the Hot Springs Basin, the largest hydrothermal system in Yellowstone. The low-velocity body has a maximum depth to the top of 3 km and a minimum depth to the bottom of 9 km and may represent a zone of partial melt. In comparison to the thermally undisturbed upper crust of the surrounding Rocky Mountains the upper crust of the northeastern Yellowstone plateau appears laterally inhomogeneous in velocity and layer thickness, suggesting effects of thermal and magma intrusion, whereas the lower crust appears relatively homogeneous.

  6. Effects of mammalian herbivore declines on plant communities: observations and experiments in an African savanna

    PubMed Central

    Young, Hillary S; McCauley, Douglas J; Helgen, Kristofer M; Goheen, Jacob R; Otárola-Castillo, Erik; Palmer, Todd M; Pringle, Robert M; Young, Truman P; Dirzo, Rodolfo

    2013-01-01

    1. Herbivores influence the structure and composition of terrestrial plant communities. However, responses of plant communities to herbivory are variable and depend on environmental conditions, herbivore identity and herbivore abundance. As anthropogenic impacts continue to drive large declines in wild herbivores, understanding the context dependence of herbivore impacts on plant communities becomes increasingly important. 2. Exclosure experiments are frequently used to assess how ecosystems reorganize in the face of large wild herbivore defaunation. Yet in many landscapes, declines in large wildlife are often accompanied by other anthropogenic activities, especially land conversion to livestock production. In such cases, exclosure experiments may not reflect typical outcomes of human-driven extirpations of wild herbivores. 3. Here, we examine how plant community responses to changes in the identity and abundance of large herbivores interact with abiotic factors (rainfall and soil properties). We also explore how effects of wild herbivores on plant communities differ between large-scale herbivore exclosures and landscape sites where anthropogenic activity has caused wildlife declines, often accompanied by livestock increases. 4. Abiotic context modulated the responses of plant communities to herbivore declines with stronger effect sizes in lower-productivity environments. Also, shifts in plant community structure, composition and species richness following wildlife declines differed considerably between exclosure experiments and landscape sites in which wild herbivores had declined and were often replaced by livestock. Plant communities in low wildlife landscape sites were distinct in both composition and physical structure from both exclosure and control sites in experiments. The power of environmental (soil and rainfall) gradients in influencing plant response to herbivores was also greatly dampened or absent in the landscape sites. One likely explanation for

  7. Measuring conditions and trends in ecosystem services at multiple scales: the Southern African Millennium Ecosystem Assessment (SAfMA) experience

    PubMed Central

    van Jaarsveld, A.S; Biggs, R; Scholes, R.J; Bohensky, E; Reyers, B; Lynam, T; Musvoto, C; Fabricius, C

    2005-01-01

    The Southern African Millennium Ecosystem Assessment (SAfMA) evaluated the relationships between ecosystem services and human well-being at multiple scales, ranging from local through to sub-continental. Trends in ecosystem services (fresh water, food, fuel-wood, cultural and biodiversity) over the period 1990–2000 were mixed across scales. Freshwater resources appear strained across the continent with large numbers of people not securing adequate supplies, especially of good quality water. This translates to high infant mortality patterns across the region. In some areas, the use of water resources for irrigated agriculture and urban–industrial expansion is taking place at considerable cost to the quality and quantity of freshwater available to ecosystems and for domestic use. Staple cereal production across the region has increased but was outstripped by population growth while protein malnutrition is on the rise. The much-anticipated wood-fuel crisis on the subcontinent has not materialized but some areas are experiencing shortages while numerous others remain vulnerable. Cultural benefits of biodiversity are considerable, though hard to quantify or track over time. Biodiversity resources remain at reasonable levels, but are declining faster than reflected in species extinction rates and appear highly sensitive to land-use decisions. The SAfMA sub-global assessment provided an opportunity to experiment with innovative ways to assess ecosystem services including the use of supply–demand surfaces, service sources and sink areas, priority areas for service provision, service ‘hotspots’ and trade-off assessments. PMID:15814355

  8. Measuring conditions and trends in ecosystem services at multiple scales: the Southern African Millennium Ecosystem Assessment (SAfMA) experience.

    PubMed

    van Jaarsveld, A S; Biggs, R; Scholes, R J; Bohensky, E; Reyers, B; Lynam, T; Musvoto, C; Fabricius, C

    2005-02-28

    The Southern African Millennium Ecosystem Assessment (SAfMA) evaluated the relationships between ecosystem services and human well-being at multiple scales, ranging from local through to sub-continental. Trends in ecosystem services (fresh water, food, fuel-wood, cultural and biodiversity) over the period 1990-2000 were mixed across scales. Freshwater resources appear strained across the continent with large numbers of people not securing adequate supplies, especially of good quality water. This translates to high infant mortality patterns across the region. In some areas, the use of water resources for irrigated agriculture and urban-industrial expansion is taking place at considerable cost to the quality and quantity of freshwater available to ecosystems and for domestic use. Staple cereal production across the region has increased but was outstripped by population growth while protein malnutrition is on the rise. The much-anticipated wood-fuel crisis on the subcontinent has not materialized but some areas are experiencing shortages while numerous others remain vulnerable. Cultural benefits of biodiversity are considerable, though hard to quantify or track over time. Biodiversity resources remain at reasonable levels, but are declining faster than reflected in species extinction rates and appear highly sensitive to land-use decisions. The SAfMA sub-global assessment provided an opportunity to experiment with innovative ways to assess ecosystem services including the use of supply-demand surfaces, service sources and sink areas, priority areas for service provision, service 'hotspots' and trade-off assessments.

  9. Passive seismic experiment and receiver functions analysis to determine crustal structure at the contact of the northern Dinarides and southwestern Pannonian Basin

    NASA Astrophysics Data System (ADS)

    Šumanovac, Franjo; Hegedűs, Endre; Orešković, Jasna; Kolar, Saša; Kovács, Attila C.; Dudjak, Darko; Kovács, István J.

    2016-06-01

    Passive seismic experiment was carried out at the SW contact of the Dinarides and Pannonian basin to determine the crustal structure and velocity discontinuities. The aim of the experiment was to define the relationship between the Adriatic microplate and the Pannonian segment as a part of the European plate. Most of the temporary seismic stations were deployed in Croatia along the Alp07 profile-a part of the active-source ALP 2002 project. About 300-km-long profile stretches from Istra peninsula to the Drava river, in a WSW-ESE direction. Teleseismic events recorded on 13 temporary seismic stations along the profile were analysed by P-receiver function method. Two types of characteristic receiver functions (RF) have been identified, belonging to Dinaridic and Pannonian crusts as defined on the Alp07 profile, while in transitional zone there are both types. Three major crustal discontinuities can be identified for the Dinaridic type: sedimentary basement, intracrustal discontinuity and Mohorovičić discontinuity, whereas the Pannonian type revealed only two discontinuities. The intracrustal discontinuity was not observed in the Pannonian type, thus pointing to a single-layered crust in the Pannonian basin. Two interpretation methods were applied: forward modelling of the receiver functions and H-κ stacking method, and the results were compared with the active-source seismic data at deep refraction profile Alp07. The receiver function modelling has given reliable results of the Moho depths that are in accordance with the seismic refraction results at the end of the Alp07 profile, that is in the area of Pannonian crust characterized by simple crustal structure and low seismic velocities (Vp between 5.9 and 6.2 km s-1). In the Dinarides and its peripheral parts, receiver function modelling regularly gives greater Moho depths, up to +15 per cent, due to more complex crustal structure. The depths of the Moho calculated by the H-κ stacking method vary within wide

  10. Fault kinematics and tectonic stress in the seismically active Manyara Dodoma Rift segment in Central Tanzania Implications for the East African Rift

    NASA Astrophysics Data System (ADS)

    Macheyeki, Athanas S.; Delvaux, Damien; De Batist, Marc; Mruma, Abdulkarim

    2008-07-01

    The Eastern Branch of the East African Rift System is well known in Ethiopia (Main Ethiopian Rift) and Kenya (Kenya or Gregory Rift) and is usually considered to fade away southwards in the North Tanzanian Divergence, where it splits into the Eyasi, Manyara and Pangani segments. Further towards the south, rift structures are more weakly expressed and this area has not attracted much attention since the mapping and exploratory works of the 1950s. In November 4, 2002, an earthquake of magnitude Mb = 5.5 struck Dodoma, the capital city of Tanzania. Analysis of modern digital relief, seismological and geological data reveals that ongoing tectonic deformation is presently affecting a broad N-S trending belt, extending southward from the North Tanzanian Divergence to the region of Dodoma, forming the proposed "Manyara-Dodoma Rift segment". North of Arusha-Ngorongoro line, the rift is confined to a narrow belt (Natron graben in Tanzania) and south of it, it broadens into a wide deformation zone which includes both the Eyasi and Manyara grabens. The two-stage rifting model proposed for Kenya and North Tanzania also applies to the Manyara-Dodoma Rift segment. In a first stage, large, well-expressed topographic and volcanogenic structures were initiated in the Natron, Eyasi and Manyara grabens during the Late Miocene to Pliocene. From the Middle Pleistocene onwards, deformations related to the second rifting stage propagated southwards to the Dodoma region. These young structures have still limited morphological expressions compared to the structures formed during the first stage. However, they appear to be tectonically active as shown by the high concentration of moderate earthquakes into earthquake swarms, the distribution of He-bearing thermal springs, the morphological freshness of the fault scarps, and the presence of open surface fractures. Fault kinematic and paleostress analysis of geological fault data in basement rocks along the active fault lines show that recent

  11. Pathways to success in science: A phenomenological study, examining the life experiences of African-American women in higher education

    NASA Astrophysics Data System (ADS)

    Giscombe, Claudette Leanora

    This study is a qualitative investigation in which five African American women science faculty, in higher education, within the age range of 45--60, were the participants. The data that was collected, over twelve months, was primarily obtained from the in-depth phenomenological interviewing method (Seidman, 1991). The interpretation of the data was the result of ongoing cross analysis of the participants' life experiences, perceptions, and beliefs of the how they navigated and negotiated pathways to careers in the natural sciences, and the meanings they attach to these experiences. The software Ethnograph (V5.0) was used to organize the participants' responses into patterns and emergent themes. The Black women in this study articulated several themes that were critical determinants of their successes and achievements in science careers. From the analysis of the data set, four major findings were identified: (1) "Black Intentional Communities" acted as social agencies for the positive development of the participants; (2) "My World Reality" which was described by the participants as their acceptance of their segregated worlds, not being victims of inequities and injustices, but being resilient and determined to forge on to early academic successes. Early academic successes were identified as precursors and external motivational stimuli to their interests and achievements in science; (3) Their experiences of "Tensions and Double Consciousness" from race and gender negative images and career stereotypes, required the women to make "intra-cultural deviations" from stereotypic career roles and to develop "pragmatic coping strategies" to achieve in science careers and; (4) "Meaning-making"---Significant to the meaning of their journey was the fact that the participants grounded their experiences in a social context rather than in a scientific context and that they ended their journey with expressions of personal satisfactions about their journey and their unique drive and

  12. Challenges associated with tracking resources allocation for reproductive health in sub-Saharan African countries: the UNFPA/NIDI resource flows project experience.

    PubMed

    Sidze, Estelle M; Beekink, Erik; Maina, Beatrice W

    2015-01-01

    Universal access to reproductive health services entails strengthening health systems, but requires significant resource commitments as well as efficient and effective use of those resources. A number of international organizations and governments in developing countries are putting efforts into tracking the flow of health resources in order to inform resource mobilization and allocation, strategic planning, priority setting, advocacy and general policy making. The UNFPA/NIDI-led Resource Flows Project ("The UNFPA/NIDI RF Project") has conducted annual surveys since 1997 to monitor progress achieved by developing countries in implementing reproductive health financial targets. This commentary summarizes the Project experiences and challenges in gathering data on allocation of resources for reproductive health at the domestic level in sub-Saharan African countries. One key lesson learnt from the Project experience is the need for strengthening tracking mechanisms in sub-Saharan African countries and making information on reproductive health resources and expenditures available, in particular the private sector resources. PMID:26012472

  13. Challenges associated with tracking resources allocation for reproductive health in sub-Saharan African countries: the UNFPA/NIDI resource flows project experience.

    PubMed

    Sidze, Estelle M; Beekink, Erik; Maina, Beatrice W

    2015-05-05

    Universal access to reproductive health services entails strengthening health systems, but requires significant resource commitments as well as efficient and effective use of those resources. A number of international organizations and governments in developing countries are putting efforts into tracking the flow of health resources in order to inform resource mobilization and allocation, strategic planning, priority setting, advocacy and general policy making. The UNFPA/NIDI-led Resource Flows Project ("The UNFPA/NIDI RF Project") has conducted annual surveys since 1997 to monitor progress achieved by developing countries in implementing reproductive health financial targets. This commentary summarizes the Project experiences and challenges in gathering data on allocation of resources for reproductive health at the domestic level in sub-Saharan African countries. One key lesson learnt from the Project experience is the need for strengthening tracking mechanisms in sub-Saharan African countries and making information on reproductive health resources and expenditures available, in particular the private sector resources.

  14. Comparative sequence stratigraphy of low-latitude versus high-latitude lacustrine rift basins: Seismic data examples from the East African and Baikal rifts

    USGS Publications Warehouse

    Scholz, C.A.; Moore, T.C.; Hutchinson, D.R.; Golmshtok, A. Ja; Klitgord, Kim D.; Kurotchkin, A.G.

    1998-01-01

    Lakes Baikal, Malawi and Tanganyika are the world's three largest rift valley lakes and are the classic modem examples of lacustrine rift basins. All the rift lakes are segmented into half-graben basins, and seismic reflection datasets reveal how this segmentation controls the filling of the rift basins through time. In the early stages of rifting, basins are fed primarily by flexural margin and axial margin drainage systems. At the climax of syn-rift sedimentation, however, when the basins are deeply subsided, almost all the margins are walled off by rift shoulder uplifts, and sediment flux into the basins is concentrated at accommodation zone and axial margin river deltas. Flexural margin unconformities are commonplace in the tropical lakes but less so in high-latitude Lake Baikal. Lake levels are extremely dynamic in the tropical lakes and in low-latitude systems in general because of the predominance of evaporation in the hydrologic cycle in those systems. Evaporation is minimized in relation to inflow in the high-latitude Lake Baikal and in most high-latitude systems, and consequently, major sequence boundaries tend to be tectonically controlled in that type of system. The acoustic stratigraphies of the tropical lakes are dominated by high-frequency and high-amplitude lake level shifts, whereas in high-latitude Lake Baikal, stratigraphic cycles are dominated by tectonism and sediment-supply variations.

  15. Results of the South African Cloud-Seeding Experiments Using Hygroscopic Flares.

    NASA Astrophysics Data System (ADS)

    Mather, G. K.; Terblanche, D. E.; Steffens, F. E.; Fletcher, L.

    1997-11-01

    A new method of seeding convective clouds for the purpose of augmenting rainfall is being developed in South Africa. Flares that produce small salt particles (0.5-m mean diameter) are attached to the trailing edge of the wings of seeding aircraft and ignited in updrafts below the cloud base of convective storms. This method of delivery overcomes most of the difficulties encountered in the handling and the use of hygroscopic materials, difficulties that made seeding with ice nuclei (AgI) a more attractive option.The research that has led to the development of this new technique was prompted by an encounter with a storm with dramatically altered microphysics that was growing over a Kraft paper mill in the research area. Hygroscopic seeding flares were subsequently developed, and seeding trials began in October 1990. Successful seeding trials quickly led to the design and execution of a randomized convective cloud-seeding experiment, the results of which show convincing evidence of increases in the radar-measured rain mass from seeded storms when compared to the control or unseeded storms.Heightened reflectivities aloft seen by the real-time storm-tracking software and observed in the exploratory analysis raises the possibility of developing a radar-measured seeding algorithm that can recognize in almost real time a successful convective seeding event. The implications of such a development would have far-reaching effects on the conduct of future convective cloud-seeding experiments and operations.The authors' seeding hypothesis postulates that the hygroscopic seeding at cloud base accelerates the growth of large hydrometeors in the treated clouds, which harvest more of the available supercooled water before it is expelled into the anvils by the strong updrafts that are a characteristic of the local storms, thereby increasing the efficiency of the rainfall process. The validity of this hypothesis is supported by microphysical measurements made from an instrumented

  16. First-Year Village: Experimenting with an African Model for First-Year Adjustment and Support in South Africa

    ERIC Educational Resources Information Center

    Speckman, McGlory

    2016-01-01

    Predicated on the principles of success and contextuality, this chapter shares an African perspective on a first-year adjustment programme, known as First-Year Village, including its potential and challenges in establishing it.

  17. Blockage and flow: intimate experiences of condoms and microbicides in a South African clinical trial.

    PubMed

    Stadler, Jonathan; Saethre, Eirik

    2011-01-01

    Based on qualitative research undertaken during a phase-three microbicide gel trial, this paper explores female participants' experiences and perceptions of gel and condom use and the opinions of their male partners and community members. Participants were aware that condoms were effective in preventing HIV infection and that the efficacy of the microbicide was unproven. Yet, in narratives about gel and condom use, participants ascribed improvements to their reproductive health and intimate relationships with men to gel use. In contrast, condoms were believed to prevent disease, yet also embodied mistrust, were believed to contain dangerous substances and were felt to block the womb. These apparently contradictory views about condoms and gels are explored in the light of conceptions of flow and blockage. Health is achieved by maintaining a steady balance of substances within the body, while preventing fluid flow results in illness. We argue that women enrolled in the trial broadened the meaning of the gel beyond its primary intended effect of preventing HIV. Through their accounts of gel use, women 'reinvented' the gel as a substance that transformed their bodies and sexual relations. This has implications for understanding how local knowledge of health and illness intersects with biomedical knowledge.

  18. Photonics, Diversity and Mentoring -- 30 Years of Experiences and Strategies of an African-American Physicist

    NASA Astrophysics Data System (ADS)

    Johnson, Anthony M.

    2010-03-01

    As requested by our Session Chair, I hope to share a career that emphasizes cutting edge research in ultrafast optical phenomena, as well as outreach to women and underrepresented minorities that began over three decades ago at Bell Laboratories. My research career in Optical Physics owes it foundation and perspective to my mid-70s participation in the Bell Labs diversity programs the Summer Research Program for Minorities and Women (SRP) and the Cooperative Research Fellowship Program for Minorities (CRFP). In addition to striving to produce leading edge research, these programs made me a strong proponent of the recruitment and retention of women and underrepresented minorities into the scientific enterprise. Now approaching 15 years in academia, I have had the good fortune to continue the research tradition, where the majority of my graduate students are women and underrepresented minorities. Indeed, these students are out there, hungry for the experience, motivated to give their best effort, and thrive when given supportive and nurturing environments -- but you must expend the energy and resources to find them and I guarantee it will be worth it!

  19. Electronic data capture in a rural African setting: evaluating experiences with different systems in Malawi

    PubMed Central

    King, Carina; Hall, Jenny; Banda, Masford; Beard, James; Bird, Jon; Kazembe, Peter; Fottrell, Ed

    2014-01-01

    Background As hardware for electronic data capture (EDC), such as smartphones or tablets, becomes cheaper and more widely available, the potential for using such hardware as data capture tools in routine healthcare and research is increasing. Objective We aim to highlight the advantages and disadvantages of four EDC systems being used simultaneously in rural Malawi: two for Android devices (CommCare and ODK Collect), one for PALM and Windows OS (Pendragon), and a custom-built application for Android (Mobile InterVA – MIVA). Design We report on the personal field and development experience of fieldworkers, project managers, and EDC system developers. Results Fieldworkers preferred using EDC to paper-based systems, although some struggled with the technology at first. Highlighted features include in-built skip patterns for all systems, and specifically the ‘case’ function that CommCare offers. MIVA as a standalone app required considerably more time and expertise than the other systems to create and could not be customised for our specific research needs; however, it facilitates standardised routine data collection. CommCare and ODK Collect both have user-friendly web-interfaces for form development and good technical support. CommCare requires Internet to build an application and download it to a device, whereas all steps can be done offline with ODK Collect, a desirable feature in low connectivity settings. Pendragon required more complex programming of logic, using a Microsoft Access application, and generally had less technical support. Start-up costs varied between systems, and all were considered more expensive than setting up a paper-based system; however running costs were generally low and therefore thought to be cost-effective over the course of our projects. Conclusions EDC offers many opportunities for efficient data collection, but brings some issues requiring consideration when designing a study; the decision of which hardware and software to use

  20. Towards 4-D Noise-based Seismic Probing of Volcanoes: Perspectives from a Large-N Nodal Experiment on Piton de la Fournaise Volcano

    NASA Astrophysics Data System (ADS)

    Brenguier, F.; Ackerley, N. J.; Nakata, N.; Boué, P.; Campillo, M.; Roux, P.; Shapiro, N.

    2015-12-01

    Noise-based seismology is proving to be a complementary approach to active source or earthquake-based methods for imaging and monitoring the Earth's interior and in particular volcanoes and active faults. Until recently, noise-based imaging and monitoring relied only on the inversion of surface waves reconstructed from correlations of mostly microseismic seismic noise. Compared to body-wave tomography, surface wave tomography succeeds in retrieving lateral sub-surface velocity contrasts but is less efficient in resolving velocity perturbations at depth. Moreover reflected body-waves can carry direct information about sharp interfaces at depth. Extracting body-waves from noise correlations is challenging and the use of Large-N seismic arrays proves to be of great benefit for extracting noisy body-waves from noise-correlations by stacking over a large number of receiver pairs and by applying array processing. The purpose of VolcArray Large-N seismic experiment on Piton de la Fournaise Volcano is to extract body-waves travelling directly through the active magma reservoir located at ~2.5 km depth below the summit crater using noise correlations between arrays of seismic nodes. By beamforming noise on individual arrays, we found an unusual strong directional source of body-wave noise. This is thus a favorable context for retrieving the body-wave component of the Green's function between arrays. However, standard correlation techniques between nodes do not allow deciphering between the reconstructed Green's function and artifacts from the correlation of the strong directional source of body-waves. By applying double beamforming to the noise correlations between arrays, we are able to isolate ballistic body-waves travelling across the magma storage zone at depth. The stability of these reconstructed waves over time is encouraging in the perspectives of high resolution monitoring of the volcano feeding system.

  1. Involving lay community researchers in epidemiological research: experiences from a seroprevalence study among sub-Saharan African migrants

    PubMed Central

    Nöstlinger, Christiana; Loos, Jasna

    2016-01-01

    ABSTRACT Community-based participatory research (CBPR) has received considerable attention during past decades as a method to increase community ownership in research and prevention. We discuss its application to epidemiological research using the case of second-generation surveillance conducted among sub-Saharan African (SSA) migrants in Antwerp city. To inform evidence-based prevention planning for this target group, this HIV-prevalence study used two-stage time-location sampling preceded by formative research. Extensive collaborative partnerships were built with community organizations, a Community Advisory Board provided input throughout the project, and community researchers were trained to participate in all phases of the seroprevalence study. Valid oral fluid samples for HIV testing were collected among 717 SSA migrants and linked to behavioural data assessed through an anonymous survey between December 2013 and August 2014. A qualitative content analysis of various data sources (extensive field notes, minutes of intervision, and training protocols) collected at 77 data collection visits in 51 settings was carried out to describe experiences with challenges and opportunities inherent to the CBPR approach at three crucial stages of the research process: building collaborative partnerships; implementing the study; dissemination of findings including prevention planning. The results show that CBPR is feasible in conducting scientifically sound epidemiological research, but certain requirements need to be in place. These include among others sufficient resources to train, coordinate, and supervise community researchers; continuity in the implementation; transparency about decision-taking and administrative procedures, and willingness to share power and control over the full research process. CBPR contributed to empowering community researchers on a personal level, and to create greater HIV prevention demand in the SSA communities. PMID:26885938

  2. Involving lay community researchers in epidemiological research: experiences from a seroprevalence study among sub-Saharan African migrants.

    PubMed

    Nöstlinger, Christiana; Loos, Jasna

    2016-01-01

    Community-based participatory research (CBPR) has received considerable attention during past decades as a method to increase community ownership in research and prevention. We discuss its application to epidemiological research using the case of second-generation surveillance conducted among sub-Saharan African (SSA) migrants in Antwerp city. To inform evidence-based prevention planning for this target group, this HIV-prevalence study used two-stage time-location sampling preceded by formative research. Extensive collaborative partnerships were built with community organizations, a Community Advisory Board provided input throughout the project, and community researchers were trained to participate in all phases of the seroprevalence study. Valid oral fluid samples for HIV testing were collected among 717 SSA migrants and linked to behavioural data assessed through an anonymous survey between December 2013 and August 2014. A qualitative content analysis of various data sources (extensive field notes, minutes of intervision, and training protocols) collected at 77 data collection visits in 51 settings was carried out to describe experiences with challenges and opportunities inherent to the CBPR approach at three crucial stages of the research process: building collaborative partnerships; implementing the study; dissemination of findings including prevention planning. The results show that CBPR is feasible in conducting scientifically sound epidemiological research, but certain requirements need to be in place. These include among others sufficient resources to train, coordinate, and supervise community researchers; continuity in the implementation; transparency about decision-taking and administrative procedures, and willingness to share power and control over the full research process. CBPR contributed to empowering community researchers on a personal level, and to create greater HIV prevention demand in the SSA communities. PMID:26885938

  3. Building capacity for the assessment of HIV drug resistance: experiences from the PharmAccess African Studies to Evaluate Resistance network.

    PubMed

    Hamers, Raph L; Straatsma, Elske; Kityo, Cissy; Wallis, Carole L; Stevens, Wendy S; Sigaloff, Kim C E; Siwale, Margaret; Conradie, Francesca; Botes, Mariette E; Mandaliya, Kishor; Wellington, Maureen; Osibogun, Akin; van Vugt, Michèle; Rinke de Wit, Tobias F

    2012-05-01

    The PharmAccess African Studies to Evaluate Resistance (PASER) network was established as a collaborative partnership of clinical sites, laboratories, and research groups in 6 African countries; its purpose is to build research and laboratory capacity in support of a coordinated effort to assess population-level acquired and transmitted human immunodeficiency virus type-1 drug resistance (HIVDR), thus contributing to the goals of the World Health Organization Global HIV Drug Resistance Network. PASER disseminates information to medical professionals and policy makers and conducts observational research related to HIVDR. The sustainability of the network is challenged by funding limitations, constraints in human resources, a vulnerable general health infrastructure, and high cost and complexity of molecular diagnostic testing. This report highlights experiences and challenges in the PASER network from 2006 to 2010. PMID:22544185

  4. Examples of the contributions of PASSCAL to controlled source seismic experiments and the promise for the future based on EarthScope

    NASA Astrophysics Data System (ADS)

    Keller, G. R.; Miller, K. C.; Harder, S. H.

    2003-04-01

    Ever since the formation of IRIS (Incorporated Research Institutions for Seismology in 1984, PASSCAL (Program for Array Seismic Studies of the Continental Lithosphere) has provided badly needed facilities for controlled source seismic experiments. After an initial period of slow growth, the PASSCAL facility now has over 1500 channels of recording capability that were designed for controlled source studies. These instruments have supported many experiments over the years. The evolution of this instrumentation has seen the size and weight decrease while capabilities and ease of use have increased. The controlled source community has a history of cooperation, and in the past four years, several experiments have succeeded in fielding over 1000 instruments by pooling international resources. Examples of large experiments include LARSE, KRISP, DELTA FORCE, DEEP PROBE, SHIPS, CD-ROM, DOBRE, POLONAISE, CELEBRATION 2000, ALP 2002, and EAGLE, and selected results from these efforts will be shown. However, all of these projects have produced valuable results about processes at work in the Earth, and with time, increasing detailed images of Earth structure. In recent years, the goal of lithospheric-scale experiments has become more ambitious, and 3-D data acquisition schemes have been attempted with some success. However, several thousand recorders and hundreds of sources are needed if large-scale experiments are to have good 3-D coverage over substantial areas. The USArray component of EarthScope includes a plan for the acquisition of 2000 of the Texan recorders. Even when coupled with 840 of these instruments currently in the PASSCAL pool, 3-D capabilities will be limited (just a 200 x 200 km area covered with recorders at a 1 km spacing would require 4000 instruments). Hopefully, European instrumentation facilities will also expand so that experiments can be conducted that will effectively address the increasing difficult questions for which society and the scientific

  5. A hermeneutic phenomenological study of the experiences of female African American undergraduate engineering students at a predominantly White and an historically Black institution

    NASA Astrophysics Data System (ADS)

    Frillman, Sharron Ann

    2011-12-01

    This phenomenological study examined the experiences of twelve female African Americans enrolled as fulltime undergraduate engineering students at North Carolina Agricultural and Technical State University, an historically Black university, and seven female African Americans enrolled as undergraduate engineering students at Purdue University in West Lafayette, Indiana, a traditionally White institution. Interviews provided insights into the "lived" experiences of these young women and the factors they believe have contributed to their success in their respective engineering programs. Data analysis involved coding each participant's responses to interview questions using Atlas.ti, a powerful qualitative data analysis tool. This generated 181 codes that were further categorized into nine emergent themes, indicating the potential for extensive associations among the variables. The emergent themes are as follows: (1) Demographic information/special circumstances, (2) Personal attributes and characteristics, (3) Personal insights, (4) Sense of mission, (5) Sources of negative stress, (6) Success strategies, (7) Various forms of support, (8) Would/would not have made it to where she is now, and (9) Being African American and female in engineering. Analysis of these themes and their relationships led to the development of the Frillman Model of Emergent Themes in Female African American Engineering Students. Success. In addressing similarities and differences, three overriding theme categories emerged. These were: (1) Four personhood themes and dual social identity theme; (2) Environmental input and response theme; and (3) Outcome emergent theme of Would/Would not have made it to where she is now. Recommendations were made for future research to expand upon this exploratory study.

  6. UNDERSTANDING THE BREAST CANCER EXPERIENCE OF WOMEN: A QUALITATIVE STUDY OF AFRICAN AMERICAN, ASIAN AMERICAN, LATINA AND CAUCASIAN CANCER SURVIVORS

    PubMed Central

    ASHING-GIWA, KIMLIN TAM; PADILLA, GERALDINE; TEJERO, JUDITH; KRAEMER, JANET; WRIGHT, KAREN; COSCARELLI, ANNE; CLAYTON, SHEILA; WILLIAMS, IMANI; HILLS, DAWN

    2006-01-01

    Breast cancer is the most common form of cancer in American women across most ethnic groups. Although the psychosocial impact of breast cancer is being studied, there is little information on women from diverse ethnic and socioeconomic backgrounds. We conducted a qualitative study with breast cancer survivors (BCS) of various ethnicities. A total of 102 BCS participated in focus group interviews (24 African Americans, 34 Asians, 26 Latinas and 18 Caucasians); 20 health professionals participated in key informant interviews. Important ethnic differences in type of treatment were noted, Asians and Latinas were more likely to receive mastectomies and African American BCS were least likely to receive adjuvant therapies, including radiation and chemotherapy. These BCS enjoyed a fairly good overall health-related quality of life (HRQOL) with some persistent concerns. The prevailing concerns among all women included overall health, moderate physical concerns, cancer recurrence or metastases, psychosocial concerns related to worry about children and burdening the family, and body image and sexual health concerns. Additional challenges included: lack of knowledge about breast cancer; medical care issues such as insurance, cost and amount of time spent with physician; cultural sensitivity of providers, language barriers, cultural factors related to beliefs about illness, gender role and family obligations (e.g. self-sacrifice). These BCS, particularly the women of color, voiced that their spiritual beliefs and practices are central to their coping. This study accomplishes two goals; it adds to the sparse literature concerning the psychosocial sequelae of breast cancer among women of color, and it increases our knowledge of specific cultural influences (e.g. dietary practices, coping) and socio-ecological factors on HRQOL. More importantly, the study addressed areas that have not been studied before, specifically, an in-depth study on BCS QOL comparing multiple ethnic groups

  7. Alignment silkworms as seismic animal anomalous behavior (SAAB) and electromagnetic model of a fault: a theory and laboratory experiment

    NASA Astrophysics Data System (ADS)

    Ikeya, Motoji; Matsumoto, Hiroshi; Huang, Qing-Hua

    1998-05-01

    Alignment of silkworms and fish, observed as seismic anomalous animal behavior (SAAB) prior to the Kobe earthquake, were duplicated in a laboratory by applying a pulsed electric field assuming SAAB as electrophysiological responses to the stimuli of seismic electric signals (SES). The animals became aligned perpendicularly to the field direction since their skeletal muscle had a higher resistivity perpendicular to the field direction than parallel to it. An electromagnetic model of a fault is proposed in which dipolar charges, ±q are generated due to the change of seismic stress, σ(t). From a mathematical model, dq/dt=-α(dσ/dt) - q/ɛρ, where α is the charge generation constant like a piezoelectric coefficient, ɛ, the dielectric constant and ρ, the resistivity of bedrock granite. A fault having a length 2a and a displacement or rock rupture time τ, during which the stress is changed, gives pulsed dipolar charge surface densities, +q(t, x) and -q(t, x+2a), or an apparent electric dipole moment of P(t)=2aQ(t)=2aAq(t)=aM 0[ɛρ/(τ-ɛρ)](e-1/τ-e-1/σρ) using the earthquake moment M 0. The fault displacement, D, its initial velocity, D‧ and the stress drop, Δσ give τ=D/D‧=(Δσ/σ 0)(α/β). The field fintensity, F, and seismic current density at a fault zone, J were calculated as F=q/ɛ and J=F/ρ‧ using ρ‧ of water as to give J=0.1-1 A/m2 sufficient to cause SAAB experimentally. The near-field ultra low frequency (ULF) waves generated by P(t) give SES reciprocally proportional to the distance R.

  8. Seismic Ecology

    NASA Astrophysics Data System (ADS)

    Seleznev, V. S.; Soloviev, V. M.; Emanov, A. F.

    The paper is devoted to researches of influence of seismic actions for industrial and civil buildings and people. The seismic actions bring influence directly on the people (vibration actions, force shocks at earthquakes) or indirectly through various build- ings and the constructions and can be strong (be felt by people) and weak (be fixed by sensing devices). The great number of work is devoted to influence of violent seismic actions (first of all of earthquakes) on people and various constructions. This work is devoted to study weak, but long seismic actions on various buildings and people. There is a need to take into account seismic oscillations, acting on the territory, at construction of various buildings on urbanized territories. Essential influence, except for violent earthquakes, man-caused seismic actions: the explosions, seismic noise, emitted by plant facilities and moving transport, radiation from high-rise buildings and constructions under action of a wind, etc. can exert. Materials on increase of man- caused seismicity in a number of regions in Russia, which earlier were not seismic, are presented in the paper. Along with maps of seismic microzoning maps to be built indicating a variation of amplitude spectra of seismic noise within day, months, years. The presence of an information about amplitudes and frequencies of oscillations from possible earthquakes and man-caused oscillations in concrete regions allows carry- ing out soundly designing and construction of industrial and civil housing projects. The construction of buildings even in not seismically dangerous regions, which have one from resonance frequencies coincident on magnitude to frequency of oscillations, emitted in this place by man-caused objects, can end in failure of these buildings and heaviest consequences for the people. The practical examples of detail of engineering- seismological investigation of large industrial and civil housing projects of Siberia territory (hydro power

  9. African American Preschoolers' Language, Emergent Literacy Skills, and Use of African American English: A Complex Relation

    ERIC Educational Resources Information Center

    Connor, Carol McDonald; Craig, Holly K.

    2006-01-01

    Purpose: This study examined the relation between African American preschoolers' use of African American English (AAE) and their language and emergent literacy skills in an effort to better understand the perplexing and persistent difficulties many African American children experience learning to read proficiently. Method: African American…

  10. Executive University Managers' Experiences of Strike and Protest Activity: A Qualitative Case Study of a South African University

    ERIC Educational Resources Information Center

    Dominguez-Whitehead, Y.

    2011-01-01

    Strike and protest activity at South African universities continues to be prevalent nearly two decades after the dismantling of apartheid, although there has been a shift away from directing strikes and protests against the government (during the apartheid era), to directing them against higher education institutions and management (since the…

  11. Experimenting in Distance Education: The African Virtual University (AVU) and the Paradox of the World Bank in Kenya

    ERIC Educational Resources Information Center

    Amutabi, M. N.; Oketch, M. O.

    2003-01-01

    This article seeks to accomplish three objectives. The first is to interrogate the efficacy of the African Virtual University (AVU), which is a satellite and information technology (IT)-based distance education system, sponsored by the World Bank in Kenya. The second is to demonstrate the failures of the AVU and the reasons why this has been the…

  12. A Peculiar Sensation: Double Consciousness and the Lived Experiences of African American Art Historians at Predominately White Institutions

    ERIC Educational Resources Information Center

    Swaidan, Christina Michelle

    2010-01-01

    Double consciousness is the identity conflict of being Black and being an American (Du Bois, 1903). Double consciousness leads to "identity confusion and inherent contradictions in the collective psyche of people of African descent" (Benjamin, 2005, p. 21.). This study employed grounded theory to collect and analyze the data that emerged from the…

  13. Retaining and Reclaiming Ourselves: Reflections on a Peer Mentoring Group Experience for New African American Women Professors

    ERIC Educational Resources Information Center

    Packer-Williams, Catherine L.; Evans, Kathy M.

    2011-01-01

    This article reports on the results of a qualitative study of new African American female professors' participation in a peer mentoring group. Three key themes that emerged from the data included peer mentoring as a vehicle to process and cope effectively with microaggressions, increase positive self-identity and self-efficacy as a scholar, and…

  14. Narratives of Agency: The Experiences of Braille Literacy Practitioners in the "Kha Ri Gude" South African Mass Literacy Campaign

    ERIC Educational Resources Information Center

    McKay, Veronica I.; Romm, Norma R. A.

    2015-01-01

    In this article, we locate the "Kha Ri Gude" South African Mass Literacy Campaign within the context of the problem of illiteracy and exclusion in South Africa, while concentrating on various post-apartheid initiatives designed to give visually challenged adults the opportunity to become literate. We shall provide a detailed account of…

  15. Influence of Kinship Social Support on the Parenting Experiences and Psychosocial Adjustment of African-American Adolescents.

    ERIC Educational Resources Information Center

    Taylor, Ronald D.; And Others

    1993-01-01

    Questionnaires assessed kinship support, psychosocial adjustment, and parenting practices for 125 African-American adolescents. Found that kinship support for adolescents was positively associated with adolescent adjustment and authoritative parenting practices in single- but not two-parent families and that parenting practices mediated the…

  16. Operating in the Middle: The Experiences of African American Female Transfer Students in STEM Degree Programs at HBCUs

    ERIC Educational Resources Information Center

    Smith, Dimitra Jackson

    2016-01-01

    Increasing the representation of African American females is essential to ensure the United States (U.S.) remains a viable competitor in the STEM (science, technology, engineering, and mathematics) workforce. With minorities anticipated to represent half of the resident U.S population by 2050, fostering STEM talent among this population is vital.…

  17. From Victory to Freedom: The African American Experience. Curriculum Guide: Elementary and Middle School Course of Study.

    ERIC Educational Resources Information Center

    Ohio Historical Society, Columbus.

    This elementary and middle school curriculum guide contains three sections of instructional materials about three areas of African American life. The section "Community Life" includes detailed lessons on family, the church, education, business, and organizations. The section "Public Life" provides in-depth lessons on media, science and medicine,…

  18. Interactive Reading Experiences of African American Fathers and Social Fathers and Their 4- and 5-Year-Old Children

    ERIC Educational Resources Information Center

    Jackson, Clarissa R.

    2012-01-01

    The purpose of this mixed-methods study was to investigate the patterns of book choice and interaction during book reading sessions of six African American fathers and social fathers and their 4- to 5-year-old children. The fathers/social fathers selected and read aloud expository text, narrative text, and poetry to their children while…

  19. The African Experience. Volume I: Syllabus Lectures; Volume II: Bibliographic References; Volume IIIA: Introductory Essays; Volume IIIB: Introductory Essays.

    ERIC Educational Resources Information Center

    Paden, John N.; Soja, Edward W.

    In response to demands for more and better teaching about Africa in American higher education, the US Office of Education requested that the Program of African Studies at Northwestern University generate a set of teaching materials which could be used in introductory undergraduate courses. Included in these volumes, these materials provide…

  20. Inclusive Education and Training in South African Higher Education: Mapping the Experiences of a Student with Physical Disability at University

    ERIC Educational Resources Information Center

    Ntombela, Sithabile

    2013-01-01

    The South African Constitution upholds and entrenches the human right of all citizens. Similarly, the Higher Education Act of 1997 promotes equality of access for all, especially for those previously marginalised or excluded. The study reported in this article explored challenges experienced by students with disabilities at his university. Using…

  1. Cooperation between scientists, NGOs and industry in support of sustainable fisheries: the South African hake Merluccius spp. trawl fishery experience.

    PubMed

    Field, J G; Attwood, C G; Jarre, A; Sink, K; Atkinson, L J; Petersen, S

    2013-10-01

    This paper examines the increasingly close interaction between natural and social scientists, non-governmental organizations (NGO) and industry, in pursuit of responsible ecosystem-based management of fisheries. South Africa has committed to implementing an ecosystem approach to fisheries management. Management advice stems from multi-stakeholder representation on government-led scientific and management working groups. In the hake Merluccius capensis and Merluccius paradoxus fishery, the primary management measure is an annual total allowable catch (TAC), the level of which is calculated using a management procedure (MP) that is revised approximately every 4 years. Revision of the MP is a consultative process involving most stakeholders, and is based on simulation modelling of projected probable scenarios of resource and fishery dynamics under various management options. NGOs, such as the Worldwide Fund for Nature in South Africa (WWF-SA), have played an important role in influencing consumers, the fishing industry and government to develop responsible fishing practices that minimize damage to marine ecosystems. Cooperation between industry, government and scientists has helped to improve sustainability and facilitated the meeting of market-based incentives for more responsible fisheries. Research includes ecosystem modelling, spatial analysis and ecosystem risk assessment with increasing research focus on social and economic aspects of the fishery. A four-year cooperative experiment to quantify the effect of trawling on benthic community structure is being planned. The food requirements of top predators still need to be included in the TAC-setting formulae and more social and economic research is needed. This paper also demonstrates how NGO initiatives such as Marine Stewardship Council certification and the Southern African Sustainable Seafood Initiative, a traffic light system of classifying seafood for consumers, have contributed to responsible fishing

  2. Using climate model experiments to explore difference between degrees of global warming: lessons from a study of African precipitation

    NASA Astrophysics Data System (ADS)

    James, Rachel; Washington, Richard

    2015-04-01

    A 2°C increase in global mean temperature (ΔTg) has been widely adopted as a benchmark for dangerous climate change, and is currently being reviewed under the United Nations Framework Convention on Climate Change. However, there has been relatively little research into the implications of 2°C, or any other degree of global warming, for regional climate. This lack of research is particularly pressing in the case of vulnerable regions, including many in Africa. In recognition of this research gap, we conducted an in depth study of changes in African temperature and precipitation associated with 1°C, 1.5°C, 2°C, 3°C, 4°C, and beyond, using output from almost 400 climate model experiments: simulations from international modelling centres (CMIP3 and CMIP5), two perturbed physics ensembles, and a group of five regional models. The implications of global warming are different depending on which models are consulted, but each model consistently shows that temperature and precipitation anomalies are enhanced progressively with global warming. At 1°C, there is little significant change, but from 1.5°C or 2°C anomalies develop which grow in magnitude and spatial extent with global temperature, for example drying over Angola, and wetting in East Africa. The main difference between ΔTg intervals is in the magnitude and spatial extent of change. There do not appear to be rapid accelerations in the rate of change or trend reversals. This is not only true for lower levels of anthropogenic forcing, but also at higher degrees of warming up to 6°C. This finding has potential implications for policy. Given that larger changes in climate are likely to generate greater challenges for society, it suggests that global temperature should be limited to the lowest level possible. It does not imply that 2°C, or any other ΔTg increment, should be a preferred target from the perspective of regional climate. However, it is important to consider whether the approximately linear

  3. Emergency preparedness activities during an ongoing seismic swarm: the experience of the 2011-2012 Pollino (Southern Italy) sequence

    NASA Astrophysics Data System (ADS)

    Masi, A.; Mucciarelli, M.; Chiauzzi, L.; De Costanzo, G.; Loperte, G.

    2012-04-01

    Facing natural disasters effects can be a very difficult task lacking suitable activities and tools to preventively prepare the involved community (people, authorities, professionals, …) to the expected events. Therefore, a suite of preventive actions should be carried out to mitigate natural risks, in particular working to reduce the territorial vulnerability with respect to the specific natural hazard at hand, and to increase people response capacity. In fact, building social capacity helps to increase the risk perception and the people capacity to adapt to and cope with natural hazards. Since October 2011 a seismic swarm is affecting the Pollino mountain range, Southern Italy. At present the sequence is still ongoing, with more than 500 events with M>1, at least 40 well perceived by the population and a maximum magnitude at 3.6. The area mainly affected by the seismic sequence includes 12 villages, with a total population of about 50.000 inhabitants and, according to the current seismic hazard map it has high seismicity level. Such area was hit by a magnitude Ml=5.7 event in 1998 that produced macroseismic intensity not higher that VII-VIII degree of MCS scale and caused one dead, some injured and widespread damage in at least six municipalities. During the sequence, the National Department of Civil Protection (DPC) and the Civil Protection of Basilicata Region decided to put in action some measures aimed at verifying and enhancing emergency preparedness. These actions have been carried out with a constant and fruitful collaboration among the main stakeholders involved (scientific community, local and national governmental agencies, civil protection volunteers, etc) trough the following main activities: 1. collaboration between scientific community and the local and national offices of Civil Protection especially in the relationship with local authorities (e.g. mayors, which are civil protection authorities in their municipality); 2. interaction between DPC

  4. Is the Caribbean plate subducting underneath Hispaniola? Preliminary results from Caribe Norte wide-angle seismic experiment

    NASA Astrophysics Data System (ADS)

    Llanes Estrada, M.; ten Brink, U. S.; Carbo-Gorosabel, A.; Granja Bruña, J.; Flores, C. H.; Davila, J. M.; Pazos, A.; Quijano, J.

    2010-12-01

    A 200 km long, wide-angle seismic refraction transect was collected in the spring of 2009, across the widest part of the Muertos compressive margin (longitude 69°W). The transect was designed to test the hypothesized subduction of the Caribbean plate’s interior beneath the eastern Greater Antilles island arc. Shots were fired every 90 seconds from the R/V Hesperides’ 3850 cubic inches water-gun array, which, towed at 5 knots, resulted in a shot spacing of ~ 230 m. The seismic signal was recorded by 5 ocean-bottom seismometers deployed at distances varying from 25 to 50 km. Gravity, bathymetry and magnetic data were also acquired along that transect. Published and reprocessed reflection seismic lines nearby provided an initial model of the sediment column and on the pattern of upper crustal reflectors. Preliminary results of a 2-D forward ray-tracing model have enabled us to outline the broad-scale crustal structure across the Muertos margin. The Caribbean oceanic slab shows considerable variations in crustal thickness in the Venezuelan basin area (Caribbean plate’s interior). Farther north, the slab is imaged underneath the Muertos margin to about 60 km north of the deformation front and up to 19 km depth,. A change in crustal p wave velocity at about 60 km from the deformation front (or 70 km from the southern coast of the Dominican Republic) is interpreted to be the boundary between the arc crust and the accretionary prism. Caribbean oceanic crust does not appear to extend farther north. We interpret the results to indicate limited overthrusting of the Caribbean slab in the muertos Trough, rather than subduction.

  5. Next-generation seismic experiments: wide-angle, multi-azimuth, three-dimensional, full-waveform inversion

    NASA Astrophysics Data System (ADS)

    Morgan, Joanna; Warner, Michael; Bell, Rebecca; Ashley, Jack; Barnes, Danielle; Little, Rachel; Roele, Katarina; Jones, Charles

    2013-12-01

    Full-waveform inversion (FWI) is an advanced seismic imaging technique that has recently become computationally feasible in three dimensions, and that is being widely adopted and applied by the oil and gas industry. Here we explore the potential for 3-D FWI, when combined with appropriate marine seismic acquisition, to recover high-resolution high-fidelity P-wave velocity models for subsedimentary targets within the crystalline crust and uppermost mantle. We demonstrate that FWI is able to recover detailed 3-D structural information within a radially faulted dome using a field data set acquired with a standard 3-D petroleum-industry marine acquisition system. Acquiring low-frequency seismic data is important for successful FWI; we show that current acquisition techniques can routinely acquire field data from airguns at frequencies as low as 2 Hz, and that 1 Hz acquisition is likely to be achievable using ocean-bottom hydrophones in deep water. Using existing geological and geophysical models, we construct P-wave velocity models over three potential subsedimentary targets: the Soufrière Hills Volcano on Montserrat and its associated crustal magmatic system, the crust and uppermost mantle across the continent-ocean transition beneath the Campos Basin offshore Brazil, and the oceanic crust and uppermost mantle beneath the East Pacific Rise mid-ocean ridge. We use these models to generate realistic multi-azimuth 3-D synthetic seismic data, and attempt to invert these data to recover the original models. We explore resolution and accuracy, sensitivity to noise and acquisition geometry, ability to invert elastic data using acoustic inversion codes, and the trade-off between low frequencies and starting velocity model accuracy. We show that FWI applied to multi-azimuth, refracted, wide-angle, low-frequency data can resolve features in the deep crust and uppermost mantle on scales that are significantly better than can be achieved by any other geophysical technique, and

  6. seismicity and seismotectonics of Libya

    NASA Astrophysics Data System (ADS)

    Ben Suleman, abdunnur

    2015-04-01

    Libya, located at the central Mediterranean margin of the African shield, underwent many episodes of orogenic activity that shaped its geological setting. The present day deformation of Libya is the result of the Eurasia-Africa continental collision. The tectonic evolution of Libya has yielded a complex crustal structure that is composed of a series of basins and uplifts. This study aims to explain in detail the seismicity and seismotectonics of Libya using new data recorded by the recently established Libyan National Seismograph Network (LNSN) incorporating other available geophysical and geological information. Detailed investigations of the Libyan seismicity indicates that Libya has experienced earthquakes of varying magnitudes The seismic activity of Libya shows dominant trends of Seismicity with most of the seismic activity concentrated along the northern coastal areas. Four major clusters of Seismicity were quit noticeable. Fault plane solution was estimated for 20 earthquakes recorded by the Libyan National Seismograph Network in northwestern and northeastern Libya. Results of fault plane solution suggest that normal faulting was dominant in the westernmost part of Libya; strike slip faulting was dominant in northern-central part of Libya. The northern-eastern part of the country suggests that dip-dip faulting were more prevalent.

  7. Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment

    NASA Astrophysics Data System (ADS)

    Ayarza, P.; Carbonell, R.; Teixell, A.; Palomeras, I.; Martí, D.; Kchikach, A.; Harnafi, M.; Levander, A.; Gallart, J.; Arboleya, M. L.; Alcalde, J.; Fernández, M.; Charroud, M.; Amrhar, M.

    2014-05-01

    crustal structure and topography of the Moho boundary beneath the Atlas Mountains of Morocco has been constrained by a controlled source, wide-angle seismic reflection transect: the SIMA experiment. This paper presents the first results of this project, consisting of an almost 700 km long, high-resolution seismic profile acquired from the Sahara craton across the High and the Middle Atlas and the Rif Mountains. The interpretation of this seismic data set is based on forward modeling by raytracing, and has resulted in a detailed crustal structure and velocity model for the Atlas Mountains. Results indicate that the High Atlas features a moderate crustal thickness, with the Moho located at a minimum depth of 35 km to the S and at around 31 km to the N, in the Middle Atlas. Upper crustal shortening is resolved at depth through a crustal root where the Saharan crust underthrusts the northern Moroccan crust. This feature defines a lower crust imbrication that, locally, places the Moho boundary at ˜40-41 km depth in the northern part of the High Atlas. The P-wave velocity model is characterized by relatively low velocities, mostly in the lower crust and upper mantle, when compared to other active orogens and continental regions. These low deep crustal velocities together with other geophysical observables such as conductivity estimates derived from MT measurements, moderate Bouguer gravity anomaly, high heat flow, and surface exposures of recent alkaline volcanism lead to a model where partial melts are currently emplaced at deep crustal levels and in the upper mantle. The resulting model supports the existence of a mantle upwelling as mechanism that would contribute significantly to sustain the High Atlas topography. However, the detailed Moho geometry deduced in this work should lead to a revision of the exact geometry and position of this mantle feature and will require new modeling efforts.

  8. Lower Crustal Seismicity, Volatiles, and Evolving Strain Fields During the Initial Stages of Cratonic Rifting

    NASA Astrophysics Data System (ADS)

    Lambert, C.; Muirhead, J.; Ebinger, C. J.; Tiberi, C.; Roecker, S. W.; Ferdinand-Wambura, R.; Kianji, G.; Mulibo, G. D.

    2014-12-01

    The volcanically active East African rift system in southern Kenya and northern Tanzania transects thick cratonic lithosphere, and comprises several basins characterized by deep crustal seismicity. The US-French-Tanzania-Kenya CRAFTI project aims to understand the role of magma and volatile movement during the initiation and evolution of rifting in cratonic lithosphere. Our 38-station broadband network spans all or parts of fault-bounded rift segments, enabling comparison of lithospheric structure, fault kinematics, and seismogenic layer thickness with age and proximity to the deeply rooted Archaen craton. Seismicity levels are high in all basins, but we find profound differences in seismogenic layer thickness along the length of the rift. Seismicity in the Manyara basin occurs almost exclusively within the lower crust, and in spatial clusters that have been active since 1990. In contrast, seismicity in the ~ 5 My older Magadi basin is localized in the upper crust, and the long border fault bounding the west side of the basin is seismically inactive. Between these two basins lies the Natron rift segment, which shows seismicity between ~ 20 and ~2 km depth, and high concentrations at Oldoinyo Lengai and Gelai volcanoes. Older volcanoes on the uplifted western flank (e.g., Ngorongoro) experience swarms of activity, suggesting that active magmatism and degassing are widespread. Focal mechanisms of the frequent earthquakes recorded across the array are spatially variable, and indicate a stress field strongly influenced by (1) Holocene volcanoes, (2) mechanical interactions between adjacent rift basins, and (3) a far-field ESE-WNW extensional stress regime. We explore the spatial correlation between zones of intense degassing along fault systems and seismicity, and examine the influence of high gas pressures on lower and upper crustal seismicity in this youthful cratonic rift zone.

  9. Next-generation seismic experiments: wide-angle, multi-azimuth, three-dimensional, full-waveform inversion

    NASA Astrophysics Data System (ADS)

    Bell, Rebecca; Morgan, Joanna; Warner, Michael

    2016-04-01

    There are many outstanding plate-tectonic scale questions that require us to know information about sub-surface physical properties, for example ascertaining the geometry and location of magma chambers and estimating the effective stress along plate boundary faults. These important scientific targets are often too deep, impractical and expensive for extensive academic drilling. Full-waveform inversion (FWI) is an advanced seismic imaging technique that has recently become feasible in three dimensions, and has been widely adopted by the oil and gas industry to image reservoir-scale targets at shallow-to-moderate depths. In this presentation we explore the potential for 3-D FWI, when combined with appropriate marine seismic acquisition, to recover high-resolution high-fidelity P-wave velocity models for sub-sedimentary targets within the crystalline crust and uppermost mantle. Using existing geological and geophysical models, we construct P-wave velocity models over three potential sub-sedimentary targets: the Soufrière Hills Volcano on Montserrat and its associated crustal magmatic system, the downgoing oceanic plate beneath the Nankai subduction margin, and the oceanic crust-uppermost mantle beneath the East Pacific Rise mid-ocean ridge. We use these models to generate realistic multi-azimuth 3-D synthetic seismic data, and attempt to invert these data to recover the original models. We explore the resolution and accuracy, sensitivity to noise and acquisition geometry, ability to invert elastic data using acoustic inversion codes, and the trade-off between low frequencies and starting velocity model accuracy. We will show that FWI applied to multi-azimuth, refracted, wide-angle, low-frequency data can resolve features in the deep crust and uppermost mantle on scales that are significantly better than can be achieved by any other geophysical technique, and that these results can be obtained using relatively small numbers (60-90) of ocean-bottom receivers combined

  10. From the Surface Topography to the Upper Mantle Beneath Central-Iberian-Zone. the Alcudia Seismic Experiments.

    NASA Astrophysics Data System (ADS)

    Carbonell, R.; Ehsan, S. A.; Ayarza, P.; Martinez-Poyatos, D. J.; Simancas, J. F.; Azor, A.; Pérez-Estaún, A.

    2014-12-01

    Normal incidence and wide-angle seismic reflection data acquired in the Central and southern parts of the Iberia Peninsula resolve the internal architecture and constrain the distribution of the physical properties along an almost 350 km long transect that samples the major tectonic domains of the Iberian Massif, including the Central Iberian Zone (CIZ) and the associated sutures. The internal architecture down to almost 70 km depth (~15 s TWTT) is resolved by the normal incidence data set. It images a number of elements that characterize the tectonics of the study area, which is one of the best exposed fragment of the Variscan orogenic Belt. A well marked brittle-to-ductile (B2D) transition separates the crust in two, the upper and mid-lower parts, approximately, 13 km and 18 km thick, respectively. The upper crust appears to be decoupled from the mid-lower crust and responded differently to shortening. The Mohorovicic discontinuity is located at ~10.5 s (TWTT) , it is relatively thick, and highly reflective beneath the CIZ. The wide-angle seismic transect extended the lithospheric section towards the north across the Madrid Basin. This profile provides very strong constraints on the distribution of physical properties (P- and S- wave velocities, Poisson's ratio) of the upper lithosphere as well as a high resolution image of the base of the crust beneath the area. This data is one of the first datasets to present solid evidence of a relatively significant crustal thickening beneath the Madrid Basin. The crustal thickness varies from ~31 km beneath the CIZ to ~35.5 km beneath the Madrid Basin. This data set also reveals two major discontinuity levels, the B2D and the Moho, both represent levels of lithological/rheological variations. The characteristics of the the PmP and SmS seismic phases suggest further details on the internal structure of the Moho. Furthermore, low fold wide-angle P and S wave stacks reveal a marked crust-mantle transition which is most

  11. High-Frequency Seismic Waves generated by Building-Shaking Experiments and Surface Wave Group Velocity Estimates from the Cross-Correlation of Data

    NASA Astrophysics Data System (ADS)

    Tanimoto, T.; Okamoto, T.

    2013-12-01

    Modeling high-frequency (>1 Hz) seismic waves is known to be difficult but it is extremely important for earthquake hazard mitigation as many buildings have resonant frequencies above 1 Hz. In this study, we examine high-frequency waves at 1.64 Hz, generated by building-shaking experiments in California. The specific data we will examine are seismic data generated by shaking experiments of the Millikan Library between 2000 and 2002, located on the campus of California Institute of Technology in Pasadena, California. The excited wavefields were recorded by the broadband seismic network in the region (~150 stations), Southern California Seismic Network (SCSN). There were about 60 stations with good signal-to-noise ratios among SCSN stations. The maximum distance for signal detection was 323 km (station GRA). Based on numerical calculations for a regional seismic structure model (SCEC Community Velocity Model 11.9), we can show that the signals are dominated by surface waves (at 1.11 Hz and 1.64 Hz), whose energy is confined to shallow depths. The focus of this report will be on the cross-correlated signals between a station in the building (station MIK) and other stations. This cross-correlation may be viewed as a source deconvolution process and will let us focus on propagation in the medium. This cross-correlated phase can be expressed as a line integral of wavenumber along a propagation path for a direct (ballistic) phase, although it may contain complexity from the caustics (the Maslov index). Somewhat to our surprise, despite the fact that we are dealing with high frequency waves (1.64 Hz), we observe well-defined constant phase in many cross-correlated seismograms. If we knew the number of cycles between the source (Millikan) and a station, we could estimate phase velocity in principle but this is not possible and seems extremely hard because the number of cycles is about 50-100 or more. However, our signals do show frequency-dependence within a narrow (signal

  12. “It's The Skin You're In”: African-American Women Talk About Their Experiences of Racism. An Exploratory Study to Develop Measures of Racism for Birth Outcome Studies

    PubMed Central

    Nuru-Jeter, Amani; Dominguez, Tyan Parker; Hammond, Wizdom Powell; Leu, Janxin; Skaff, Marilyn; Egerter, Susan; Jones, Camara P.; Braveman, Paula

    2011-01-01

    Objectives Stress due to experiences of racism could contribute to African-American women's adverse birth outcomes, but systematic efforts to measure relevant experiences among childbearing women have been limited. We explored the racism experiences of childbearing African-American women to inform subsequent development of improved measures for birth outcomes research. Methods Six focus groups were conducted with a total of 40 socioeconomically diverse African-American women of childbearing age in four northern California cities. Results Women reported experiencing racism (1) throughout the lifecourse, with childhood experiences seeming particularly salient and to have especially enduring effects (2) directly and vicariously, particularly in relation to their children; (3) in interpersonal, institutional, and internalized forms; (4) across different life domains; (5) with active and passive responses; and (6) with pervasive vigilance, anticipating threats to themselves and their children. Conclusions This exploratory study's findings support the need for measures reflecting the complexity of childbearing African-American women's racism experiences. In addition to discrete, interpersonal experiences across multiple domains and active/passive responses, which have been measured, birth outcomes research should also measure women's childhood experiences and their potentially enduring impact, perceptions of institutionalized racism and internalized negative stereotypes, vicarious experiences related to their children, vigilance in anticipating future racism events, as well as the pervasiveness and chronicity of racism exposure, all of which could be sources of ongoing stress with potentially serious implications for birth outcomes. Measures of racism addressing these issues should be developed and formally tested. PMID:18463971

  13. Seismic seiches

    USGS Publications Warehouse

    McGarr, Arthur; Gupta, Harsh K.

    2011-01-01

    Seismic seiche is a term first used by Kvale (1955) to discuss oscillations of lake levels in Norway and England caused by the Assam earthquake of August 15, 1950. This definition has since been generalized to apply to standing waves set up in closed, or partially closed, bodies of water including rivers, shipping channels, lakes, swimming pools and tanks due to the passage of seismic waves from an earthquake.

  14. The Experience of Antiretroviral Treatment for Black West African Women who are HIV Positive and Living in London: An Interpretative Phenomenological Analysis.

    PubMed

    Spiers, Johanna; Smith, Jonathan A; Poliquin, Elizabeth; Anderson, Jane; Horne, Rob

    2016-09-01

    Antiretroviral therapy (ART) offers a powerful intervention in HIV but effectiveness can be compromised by inadequate adherence. This paper is a detailed examination of the experience of medication in a purposively selected group of people living with HIV. In-depth interviews were conducted with 10 HIV positive, West African women of black heritage living in London, UK. This group was of interest since it is the second largest group affected by HIV in the UK. Interviews were subjected to interpretative phenomenological analysis, an idiographic, experiential, qualitative approach. The paper details the women's negative experience of treatment. ART can be considered difficult and unrelenting and may be disconnected from the women's sense of health or illness. Participants' social context often exacerbated the difficulties. Some reported an improvement in their feelings about the medication over time. These findings point to some intrinsic and social motivators which could act as spurs to adherence.

  15. Topography and tectonics of the central New Madrid seismic zone: Results of numerical experiements using a three-dimensional boundary element program

    NASA Technical Reports Server (NTRS)

    Gomberg, Joan; Ellis, Michael

    1994-01-01

    We present results of a series of numerical experiments designed to test hypothetical mechanisms that derive deformation in the New Madrid seismic zone. Experiments are constrained by subtle topography and the distribution of seismicity in the region. We use a new boundary element algorithm that permits calcuation of the three-dimensional deformation field. Surface displacement fields are calculated for the New Madrid zone under both far-field (plate tectonics scale) and locally derived driving strains. Results demonstrate that surface displacement fields cannot distinguish between either a far-field simple or pure shear strain field or one that involves a deep shear zone beneath the upper crustal faults. Thus, neither geomorphic nor geodetic studies alone are expected to reveal the ultimate driving mechanism behind the present-day deformation. We have also tested hypotheses about strain accommodation within the New Madrid contractional step-over by including linking faults, two southwest dipping and one vertical, recently inferred from microearthquake data. Only those models with step-over faults are able to predict the observed topography. Surface displacement fields for long-term, relaxed deformation predict the distribution of uplift and subsidence in the contractional step-over remarkably well. Generation of these displacement fields appear to require slip on both the two northeast trending vertical faults and the two dipping faults in the step-over region, with very minor displacements occurring during the interseismic period when the northeast trending vertical faults are locked. These models suggest that the gently dippling central step-over fault is a reverse fault and that the steeper fault, extending to the southeast of the step-over, acts as a normal fault over the long term.

  16. Seismic Census Technique for African Elephants

    NASA Astrophysics Data System (ADS)

    Wood, J. D.; O'Connell-Rodwell, C. E.; Klemperer, S. L.

    2005-12-01

    Large mammal populations are difficult to census and monitor in remote areas. In particular, elephant populations in Central Africa are difficult to census due to dense forest making aerial surveys impractical. Conservation management would be improved by a census technique that was accurate and precise, did not require large efforts in the field, and could record numbers of animals over a period of time. We report a new detection technique that relies on sensing the footfalls of large mammals. Geophones were used to record the footfalls of elephants and other large mammal species at a water hole in Etosha National Park, Namibia. We were able to discriminate between species using the spectral content of their footfalls with an 85% accuracy rate while only using a single geophone. This was done using correlation coefficients comparing the shape of the spectra for various species. An ANOVA found significant differences between these correlation coefficients (F4,1785 = 147.78, P = 0.000). An estimate of the energy created by passing elephants (the area under the amplitude envelope) can be used to estimate the number of elephants passing the geophone. Our best regression line plotting number of elephants versus energy recorded in the geophone explained 55% of the variance in the data. Much of the unexplained variance is due to the variation in distance from the geophone to the passing elephants. By subjecting the recordings to a narrow band-pass filter and using beamforming techniques on array data, we believe that we can control for the variation in distance between animal and geophones, and thus achieve better estimates of the number of animals passing the array. Using 7 pairs of geophones in a linear array, we offset the pairs of time series to correspond with the time delay associated with the signal intersecting the pair of geophones at increments of 2 degrees. The offset time series were then summed and the RMS value calculated. The largest RMS value was then taken to indicate the most likely angle from which the signal intersected the pair of geophones. Lines were then plotted from the pairs of geophones at the angle with the highest RMS. The centroid of the line intersections was taken to be the location of the source signal. Thus far we have managed to localize the signal source within 15 meters of its true location.

  17. Seismicity of southern Lake Tanganyika

    NASA Astrophysics Data System (ADS)

    Lavayssiere, A.; Gallacher, R. J.; Keir, D.; Ebinger, C. J.; Drooff, C.; Khalfan, M.; Bull, J. M.

    2015-12-01

    Global seismic networks document frequent and unusually deep earthquakes in East African rift sectors lacking central volcanoes. The deep seismicity means that we can use earthquakes to probe the geometry and kinematics of fault systems throughout the crust, and to understand the distribution of strain between large offset border fault systems and intrabasinal faults. The southern Tanganyika rift zone has the highest seismicity rate within East Africa during the period 1973-present, yet earlier temporary seismometer networks have been too sparse in space and time to relocate earthquakes with location and depth errors of < 5-10 km. We address this issue by recording seismicity of southern Lake Tanganyika since June 2014 using a network at 12 broadband seismic stations. The distribution of earthquakes shows that deformation primarily occurs on large offset border faults beneath the lake. Subsidiary earthquake activity occurs along the subparrallel Rukwa graben, and beneath the NE-SW striking Mweru rift. The distribution of earthquakes suggests the southern end of lake Tanganyika is characterized by a network of intersecting NNW and NE striking faults. The depths of earthquakes are distributed throughout the crust, consistent with the relatively strong lithosphere.

  18. Seismic bearing

    NASA Astrophysics Data System (ADS)

    Power, Dennis

    2009-05-01

    Textron Systems (Textron) has been using geophones for target detection for many years. This sensing capability was utilized for detection and classification purposes only. Recently Textron has been evaluating multiaxis geophones to calculate bearings and track targets more specifically personnel. This capability will not only aid the system in locating personnel in bearing space or cartesian space but also enhance detection and reduce false alarms. Textron has been involved in the testing and evaluation of several sensors at multiple sites. One of the challenges of calculating seismic bearing is an adequate signal to noise ratio. The sensor signal to noise ratio is a function of sensor coupling to the ground, seismic propagation and range to target. The goals of testing at multiple sites are to gain a good understanding of the maximum and minimum ranges for bearing and detection and to exploit that information to tailor sensor system emplacement to achieve desired performance. Test sites include 10A Site Devens, MA, McKenna Airfield Ft. Benning, GA and Yuma Proving Ground Yuma, AZ. Geophone sensors evaluated include a 28 Hz triax spike, a 15 Hz triax spike and a hybrid triax spike consisting of a 10 Hz vertical geophone and two 28 Hz horizontal geophones. The algorithm uses raw seismic data to calculate the bearings. All evaluated sensors have triaxial geophone configuration mounted to a spike housing/fixture. The suite of sensors also compares various types of geophones to evaluate benefits in lower bandwidth. The data products of these tests include raw geophone signals, seismic features, seismic bearings, seismic detection and GPS position truth data. The analyses produce Probability of Detection vs range, bearing accuracy vs range, and seismic feature level vs range. These analysis products are compared across test sites and sensor types.

  19. African and African Caribbean users' perceptions of inpatient services.

    PubMed

    Secker, J; Harding, C

    2002-04-01

    It has been suggested that well-documented differences in African and African Caribbean people's contact with mental health services may stem from the organization, processes and practices of services themselves. This article presents the findings of a qualitative study which explored the inpatient experiences of a sample of African and African Caribbean people. Although some positive experiences were described, in the main, participants' accounts revolved around a sense of loss of control and around experiences of overt and implicit racism. Underpinning these experiences were relationships with staff that were perceived to be unhelpful. On the basis of both the positive and negative experiences described, we draw conclusions about the changes required to ensure that inpatient services more effectively meet the needs of this group.

  20. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2002-10-01

    RSI has access to two synthetic seismic programs: Osiris seismic modeling system provided by Odegaard (Osiris) and synthetic seismic program, developed by SRB, implementing the Kennett method for normal incidence. Achieving virtually identical synthetic seismic traces from these different programs serves as cross-validation for both. The subsequent experiments have been performed with the Kennett normal incidence code because: We have access to the source code, which allowed us to easily control computational parameters and integrate the synthetics computations with our graphical and I/O systems. This code allows to perform computations and displays on a PC in MatLab or Octave environment, which is faster and more convenient. The normal incidence model allows us to exclude from the synthetic traces some of the physical effects that take place in 3-D models (like inhomogeneous waves) but have no relevance to the topic of our investigation, which is attenuation effects on seismic reflection and transmission.

  1. "Give a Brotha a Break!": The Experiences and Dilemmas of Middle-Class African American Male Students in White Suburban Schools

    ERIC Educational Resources Information Center

    Gordon, Beverly M.

    2012-01-01

    Background/Context: Today, in the era of the first African American president, approximately one third of all African Americans live in suburban communities, and their children are attending suburban schools. Although most research on the education of African American students, particularly males, focuses on their plight in urban schooling, what…

  2. Oncology pharmacy units: a safety policy for handling hazardous drugs and related waste in low- and middle-income African countries—Angolan experience

    PubMed Central

    da Conceição, Ana Vaz; Bernardo, Dora; Lopes, Lygia Vieira; Miguel, Fernando; Bessa, Fernanda; Monteiro, Fernando; Santos, Cristina; Oliveira, Blasques; Santos, Lúcio Lara

    2015-01-01

    In African countries, higher rates of late-stage cancers at the time of first diagnosis are a reality. In this context, hazardous drugs (HDs), such as chemotherapy, play an important role and have immense benefits for patients’ treatment. HDs should be handled under specific conditions. At least a class 5 environment primary engineering control (PEC), physically located in an appropriate buffer area, is mandatory for sterile HDs compounding, as well as administrative control, personal protective equipment, work practices and other engineering and environmental controls, in order to protect the environment, patient, and worker. The aim of this study is to describe the Angolan experience regarding the development of oncology pharmacy units and discuss international evidence-based guidelines on handling HDs and related waste. Measures to incorporate modern and economical solutions to upgrade or build adequate and safe facilities and staff training, in order to comply with international guidelines in this area, are crucial tasks for African countries of low and middle income. PMID:26557873

  3. Experiences of racial discrimination and relation to sexual risk for HIV among a sample of urban black and African American men.

    PubMed

    Reed, E; Santana, M C; Bowleg, L; Welles, S L; Horsburgh, C R; Raj, A

    2013-04-01

    This study aimed to examine racial discrimination and relation to sexual risk for HIV among a sample of urban black and African American men. Participants of this cross-sectional study were black and African American men (N = 703) between the ages of 18 and 65 years, recruited from four urban clinical sites in the northeast. Multivariate logistic regression models were used to analyze the relation of reported racial discrimination to the following: (1) sex trade involvement, (2) recent unprotected sex, and (3) reporting a number of sex partners in the past 12 months greater than the sample average. The majority of the sample (96%) reported racial discrimination. In adjusted analyses, men reporting high levels of discrimination were significantly more likely to report recent sex trade involvement (buying and/or selling) (adjusted odds ratio (AOR) range = 1.7-2.3), having recent unprotected vaginal sex with a female partner (AOR = 1.4, 95% confidence interval (CI), 1.1-2.0), and reporting more than four sex partners in the past year (AOR = 1.4, 95% CI, 1.1-1.9). Findings highlight the link between experiences of racial discrimination and men's sexual risk for HIV.

  4. Seismic wave propagation in the MELT Experiment area: Probing the nature of intraplate earthquakes, lithospheric anisotropy and mantle upwelling in the vicinity of the southern East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Hung, Shu-Huei

    This thesis conducts comprehensive investigations of on-going tectonic processes from observations and modeling of seismic waves propagating through the MELT Experiment area across the southern East Pacific Rise (EPR). In Chapter One, a moment-tensor inversion procedure is developed to derive the source mechanism of a sequence of teleseismic earthquakes about 300 km west of the 18sp°S EPR. All the determined events are nearly pure normal faults striking in a variety of directions with significant non-double-couple components, which are likely due to simultaneously slip on randomly-oriented fault planes. The summed moment tensor indicates no preferred orientation of horizontal extension with maximum vertical compression, consistent with the release of thermal stresses in the cooling oceanic seafloor. In Chapter Two, a parallel multi-domain pseudospectral method is developed for simulation of seismic wave propagation in generalized inhomogeneous and anisotropic media. We illustrate the variabilities in wavefront geometry and waveform complexity for different anisotropic symmetries present in the Earth. In Chapter Three, we measure shear wave splitting parameters to constrain lithospheric anisotropy in the vicinity of the earthquake swarm. Most of the resolving fast polarization directions are subparallel to the plate motion vector, attributable to crystal fabrics formed by shearing mantle flow. Some of them are scattered nearly orthogonal to the spreading direction, associated with crack-induced crustal anisotropy. Waveform modeling is employed to test the hypothesis of double-layered anisotropy. The models reconstruct the observed splitting pattern and demonstrate that shear waves split in nonuniform anisotropic layers display frequency-dependent behavior. In Chapter Four, we combine observed and synthetic waveforms and travel-time delays recorded in the MELT seismometer array to characterize the nature of mantle upwelling beneath the EPR. The similar waveforms and

  5. Next-generation seismic experiments - II: wide-angle, multi-azimuth, 3-D, full-waveform inversion of sparse field data

    NASA Astrophysics Data System (ADS)

    Morgan, Joanna; Warner, Michael; Arnoux, Gillean; Hooft, Emilie; Toomey, Douglas; VanderBeek, Brandon; Wilcock, William

    2016-02-01

    3-D full-waveform inversion (FWI) is an advanced seismic imaging technique that has been widely adopted by the oil and gas industry to obtain high-fidelity models of P-wave velocity that lead to improvements in migrated images of the reservoir. Most industrial applications of 3-D FWI model the acoustic wavefield, often account for the kinematic effect of anisotropy, and focus on matching the low-frequency component of the early arriving refractions that are most sensitive to P-wave velocity structure. Here, we have adopted the same approach in an application of 3-D acoustic, anisotropic FWI to an ocean-bottom-seismometer (OBS) field data set acquired across the Endeavour oceanic spreading centre in the northeastern Pacific. Starting models for P-wave velocity and anisotropy were obtained from traveltime tomography; during FWI, velocity is updated whereas anisotropy is kept fixed. We demonstrate that, for the Endeavour field data set, 3-D FWI is able to recover fine-scale velocity structure with a resolution that is 2-4 times better than conventional traveltime tomography. Quality assurance procedures have been employed to monitor each step of the workflow; these are time consuming but critical to the development of a successful inversion strategy. Finally, a suite of checkerboard tests has been performed which shows that the full potential resolution of FWI can be obtained if we acquire a 3-D survey with a slightly denser shot and receiver spacing than is usual for an academic experiment. We anticipate that this exciting development will encourage future seismic investigations of earth science targets that would benefit from the superior resolution offered by 3-D FWI.

  6. Windows into the solid-state viscosity and seismic anisotropy of Earth's inner core inferred from experiments on micro-fabricated, controlled-geometry samples

    NASA Astrophysics Data System (ADS)

    Reaman, D. M.; Colijn, H. J.; Panero, W. R.

    2008-12-01

    The diffusion coefficients of core materials provide important constraints on the solid-state viscosity of the inner core, which governs the dominant mechanism for observed seismic anisotropy. Of considerable interest is the grain size and defect structure present in Earth's solid inner core, and what effect that may have on rates of diffusion. To quantify Fe/Ni diffusion under high pressure and temperature conditions, multi-layered, controlled-geometry samples were prepared for use in the laser-heated diamond anvil cell. These samples are composed of a Fe64Ni36 alloy foil substrate with 300 nm of Ni sputter-deposited atop the alloy foil to introduce an initial discontinuity in the samples. Fe and Ni were used because they are the two elements that comprise ~90% of the inner core. Experiments were performed at pressures of 20-50 GPa and laser heated to homologous temperatures of 0.8-1.1 Tm. We present results on TEM (transmission electron microscopy) analysis of prepared foils both before and after heating in order to gain a better understanding of the defect structure in our samples, and whether there is sufficient time for the defects to anneal themselves under the time constraints of laser heating. Results of EDS (energy dispersive x-ray spectroscopy) analysis through a cross-section of the hotspot provide compositional profiles across the initial compositional discontinuity to determine diffusion coefficients of core materials. The combined result of diffusivities and defect densities then allow for an examination of creep mechanisms in core materials under conditions of high pressure and temperature, resulting in insight into the solid-state viscosity of the inner core and the deformation mechanism responsible for observed seismic anisotropy.

  7. Drill-rig noise suppression using the Karhunen-Loéve transform for seismic-while-drilling experiment at Brukunga, South Australia

    NASA Astrophysics Data System (ADS)

    Sun, Baichun; Bóna, Andrej; Zhou, Binzhong; King, Andrew; Dupuis, Christian; Kepic, Anton

    2016-02-01

    Diamond-impregnated drill bits are known to be low energy vibration seismic sources. With the strong interference from the drill rig, it is difficult to obtain the drill-bit wavefield with a surface receiver array. To overcome the challenge of surface wave interference generated from the rig for seismic-while-drilling (SWD), we need to separate the rig- and bit-generated signals. To this end, we apply two wavefield separation methods, the Karhunen-Loéve (KL) transform and the f - k filter, and compare their performance. The applicability of these methods is based on the drill rig and drill bit having different spatial positions. While the drill-bit spatial position changes during the process of drilling, the drill rig remains stationary. This results in the source wavefields from the drill rig and the drill-bit having different characteristics, and allows us to separate and extract the drill-bit signal. We use a synthetic model to compare the KL transform and f - k filter. Both techniques are robust when the noise wavefield has consistent amplitude moveout. However, for changing amplitudes, such as the rig noise, which has an unrepeatable wavefield due to power amplitude variation, we show that the KL transform performs better in such situations. We also show the results of signal analysis of the SWD experiment data acquired from Brukunga, South Australia. We demonstrate the feasibility of the KL transform in separating the coherent noises from the stationary drill rig in a hard rock drilling environment, particularly emphasising the suppression of the surface and direct waves from the rig. The results show that drill-rig noise can be effectively suppressed in the correlation domain.

  8. Seismic Studies

    SciTech Connect

    R. Quittmeyer

    2006-09-25

    This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground motion at

  9. Seismic sequences in the Sombrero Seismic Zone

    NASA Astrophysics Data System (ADS)

    Pulliam, J.; Huerfano, V. A.; ten Brink, U.; von Hillebrandt, C.

    2007-05-01

    The northeastern Caribbean, in the vicinity of Puerto Rico and the Virgin Islands, has a long and well-documented history of devastating earthquakes and tsunamis, including major events in 1670, 1787, 1867, 1916, 1918, and 1943. Recently, seismicity has been concentrated to the north and west of the British Virgin Islands, in the region referred to as the Sombrero Seismic Zone by the Puerto Rico Seismic Network (PRSN). In the combined seismicity catalog maintained by the PRSN, several hundred small to moderate magnitude events can be found in this region prior to 2006. However, beginning in 2006 and continuing to the present, the rate of seismicity in the Sombrero suddenly increased, and a new locus of activity developed to the east of the previous location. Accurate estimates of seismic hazard, and the tsunamigenic potential of seismic events, depend on an accurate and comprehensive understanding of how strain is being accommodated in this corner region. Are faults locked and accumulating strain for release in a major event? Or is strain being released via slip over a diffuse system of faults? A careful analysis of seismicity patterns in the Sombrero region has the potential to both identify faults and modes of failure, provided the aggregation scheme is tuned to properly identify related events. To this end, we experimented with a scheme to identify seismic sequences based on physical and temporal proximity, under the assumptions that (a) events occur on related fault systems as stress is refocused by immediately previous events and (b) such 'stress waves' die out with time, so that two events that occur on the same system within a relatively short time window can be said to have a similar 'trigger' in ways that two nearby events that occurred years apart cannot. Patterns that emerge from the identification, temporal sequence, and refined locations of such sequences of events carry information about stress accommodation that is obscured by large clouds of

  10. The African-American History of Martha's Vineyard.

    ERIC Educational Resources Information Center

    Weintraub, Elaine

    1993-01-01

    Reports on research into African American history and experiences in Martha's Vineyard (Massachusetts). Examines primary sources and oral traditions of African American cultural and social history from 1703 to the present. Discusses African American sailors, race relations, and contributions by African American individuals to the community. (CFR)

  11. "Come on Baby. You Know I Love You": African American Women's Experiences of Communication with Male Partners and Disclosure in the Context of Unwanted Sex.

    PubMed

    Gutzmer, Kyle; Ludwig-Barron, Natasha T; Wyatt, Gail E; Hamilton, Alison B; Stockman, Jamila K

    2016-05-01

    We examined African American women's experiences of communication with their male intimate partners a couple of hours before and after an incident of unwanted sex. We also examined women's experiences of disclosure following an incident of unwanted sex. Semi-structured qualitative interviews were conducted with a community-based sample of sexually active African American women (n = 19) reporting at least one incident of sexual coercion (i.e., being pressured into unwanted sex without consent) by an intimate male partner since the age of 18. Our analysis was guided by "the sexual division of power" from Connell's (1987) theory of gender and power. Data were analyzed inductively by examining the interviews for common themes in the following domains: communication before the unwanted sex, communication after the unwanted sex, and disclosure to others. Men pressured partners for unwanted sex through verbal and non-verbal tactics, ranging from pestering and blunt requests for sex to verbal bullying and violence. Many women responded by clearly saying no. However, many women also described eventually ceasing to resist their partners and engaging in unwanted sex. After the unwanted sex, men actively and passively avoided discussing the incident. Although many women discussed the unwanted sex with family and friends, less women disclosed to trained professionals. In some cases, women did not discuss the incident with anyone at all. These findings indicate that, when addressing sexual violence against women, there is a need to target men as well as the norms of masculinity that underpin physical and sexual violence against women. PMID:26892099

  12. "Come on Baby. You Know I Love You": African American Women's Experiences of Communication with Male Partners and Disclosure in the Context of Unwanted Sex.

    PubMed

    Gutzmer, Kyle; Ludwig-Barron, Natasha T; Wyatt, Gail E; Hamilton, Alison B; Stockman, Jamila K

    2016-05-01

    We examined African American women's experiences of communication with their male intimate partners a couple of hours before and after an incident of unwanted sex. We also examined women's experiences of disclosure following an incident of unwanted sex. Semi-structured qualitative interviews were conducted with a community-based sample of sexually active African American women (n = 19) reporting at least one incident of sexual coercion (i.e., being pressured into unwanted sex without consent) by an intimate male partner since the age of 18. Our analysis was guided by "the sexual division of power" from Connell's (1987) theory of gender and power. Data were analyzed inductively by examining the interviews for common themes in the following domains: communication before the unwanted sex, communication after the unwanted sex, and disclosure to others. Men pressured partners for unwanted sex through verbal and non-verbal tactics, ranging from pestering and blunt requests for sex to verbal bullying and violence. Many women responded by clearly saying no. However, many women also described eventually ceasing to resist their partners and engaging in unwanted sex. After the unwanted sex, men actively and passively avoided discussing the incident. Although many women discussed the unwanted sex with family and friends, less women disclosed to trained professionals. In some cases, women did not discuss the incident with anyone at all. These findings indicate that, when addressing sexual violence against women, there is a need to target men as well as the norms of masculinity that underpin physical and sexual violence against women.

  13. Report for borehole explosion data acquired in the 1999 Los Angeles Region Seismic Experiment (LARSE II), Southern California: Part I, description of the survey

    USGS Publications Warehouse

    Fuis, Gary S.; Murphy, Janice M.; Okaya, David A.; Clayton, Robert W.; Davis, Paul M.; Thygesen, Kristina; Baher, Shirley A.; Ryberg, Trond; Benthien, Mark L.; Simila, Gerry; Perron, J. Taylor; Yong, Alan K.; Reusser, Luke; Lutter, William J.; Kaip, Galen; Fort, Michael D.; Asudeh, Isa; Sell, Russell; Van Schaack, John R.; Criley, Edward E.; Kaderabek, Ronald; Kohler, Will M.; Magnuski, Nickolas H.

    2001-01-01

    The Los Angeles Region Seismic Experiment (LARSE) is a joint project of the U.S. Geological Survey (USGS) and the Southern California Earthquake Center (SCEC). The purpose of this project is to produce seismic images of the subsurface of the Los Angeles region down to the depths at which earthquakes occur, and deeper, in order to remedy a deficit in our knowledge of the deep structure of this region. This deficit in knowledge has persisted despite over a century of oil exploration and nearly 70 years of recording earthquakes in southern California. Understanding the deep crustal structure and tectonics of southern California is important to earthquake hazard assessment. Specific imaging targets of LARSE include (a) faults, especially blind thrust faults, which cannot be reliably detected any other way; and (b) the depths and configurations of sedimentary basins. Imaging of faults is important in both earthquake hazard assessment but also in modeling earthquake occurrence. Earthquake occurrence cannot be understood unless the earthquake-producing "machinery" (tectonics) is known (Fuis and others, 2001). Imaging the depths and configurations of sedimentary basins is important because earthquake shaking at the surface is enhanced by basin depth and by the presence of sharp basin edges (Wald and Graves, 1998, Working Group on California Earthquake Probabilities, 1995; Field and others, 2001). (Sedimentary basins are large former valleys now filled with sediment eroded from nearby mountains.) Sedimentary basins in the Los Angeles region that have been investigated by LARSE include the Los Angeles, San Gabriel Valley, San Fernando Valley, and Santa Clarita Valley basins. The seismic imaging surveys of LARSE include recording of earthquakes (both local and distant earthquakes) along several corridors (or transects) through the Los Angeles region and also recording of man-made sources along these same corridors. Man-made sources have included airguns offshore and borehole

  14. Extension and magmatism across the Suwanee Suture and South Georgia Basin from the SUGAR seismic refraction experiment

    NASA Astrophysics Data System (ADS)

    Shillington, D. J.; Lizarralde, D.; Harder, S. H.; Marzen, R.; Kaip, G.; Accardo, N. J.; Gibson, J. C.; Nauer, A.

    2015-12-01

    The South Georgia Basin was at the center of the most recent sequence of continental collision and rifting events to shape eastern North America. It is the largest of the failed Mesozoic rift basins that formed during the breakup of Pangea, and it straddles the Suwannee Suture, the only well-defined remnant of the Alleghenian suture that joined North America and Gondwana. The South Georgia Basin also lies at the center of the Central Atlantic Magmatic Province (CAMP). It is thus an excellent location to examine the importance of magmatism and pre-existing structures on continental extension. Here we present preliminary results from the SUwanee Suture and GA Rift basin (SUGAR) project, an active-source seismic refraction project to image the crustal structure across these features. In March 2014, we acquired data along SUGAR Line 1, a ~325-km-long, NW-SE oriented profile that crossed the Suwanee Suture and western part of South Georgia Basin. The profile was densely instrumented with 1193 single-channel RekTek 125A seismographs ("Texans") spaced at ~250 m. The sources were 100 to 1800 lb shots spaced at ~20-50 km. In August 2015, we will acquire data along SUGAR Lines 2 and 3. SUGAR Line 2 is a ~450-km-long profile spanning the eastern part of the South Georgia Basin and two possible locations for the Suwanee Suture. We will deploy 1983 "Texans" spaced at 250 m and detonate seventeen 400 to 1600 lb shots spaced at ~16-50 km. SUGAR Line 3 targets the Brunswick magnetic anomaly; we plan to instrument a 100-km-long profile with 700 Texans spaced at 150 m and eleven 200 lb shots spaced at ~10 km. Over 68 students participated in field work for SUGAR. Preliminary models of SUGAR Line 1 indicate that the crust thins to ~33 km beneath the South Georgia Basin. Anomalously high lower crustal velocities occur beneath the basin in the area of the greatest crustal thinning and may represent mafic intrusions from CAMP/synrift magmatism. We will present initial velocity models of

  15. Initial constraints on crustal structure across the Suwanee Suture and South Georgia Basin from the SUGAR seismic refraction experiment

    NASA Astrophysics Data System (ADS)

    Shillington, D. J.; Lizarralde, D.; Harder, S. H.

    2014-12-01

    Some of the most important unresolved questions in plate tectonics concern the formation and rupture of continents. How does the accretion of terranes contribute to the construction of continental lithosphere, and what processes enable continental lithosphere to rupture? The South Georgia Basin was at the center of the most recent sequence of continental collision and rifting events to shape eastern North America. It is the largest of the failed Mesozoic rift basins that formed during the breakup of Pangea. It straddles the Suwannee Suture, the only well-defined remnant of the Alleghenian suture that joined North America and Gondwana, forming Pangea. The South Georgia Basin also lies at the center of the Central Atlantic Magmatic Province (CAMP). Here we present initial results from the first phase of the SUwanee Suture and GA Rift basin (SUGAR) project, an active-source seismic refraction project to image the crustal structure across these features. During March 2014, we acquired data along a ~325-km-long, NW-SE oriented profile that crossed the Suwanne Suture and western part of South Georgia Basin, extending from north of Columbus, GA to northernmost Florida east of Jasper, FL. The profile was densely instrumented with single-channel RekTek 125A seismometers ("Texans") spaced at ~250 m and deployed along state and country roads, yielding a total of 1193 seismometers along the profile. Thirty-three students and young scientists were involved in the deployment and recovery. The sources were 100 to 1800 lb shots spaced at ~20-50 km. The data are of exceptionally high quality. On nearly all shots, we observe arrivals out to the largest shot-receiver offsets. Within the basin, refractions through the sedimentary section with apparent velocities of ~3-4 km/s are observed to maximum offsets of 7 km. Crustal refractions are observed at a wide-range of offsets with apparent velocities increasing from ~5.5 km/s to as high as ~7.25 km/s. At offsets greater than 150-180 km

  16. Seismicity of the eastern Hellenic Subduction Zone

    NASA Astrophysics Data System (ADS)

    Bruestle, A.; Kueperkoch, L.; Rische, M.; Meier, T.; Friederich, W.; Egelados Working Group

    2012-04-01

    The Hellenic Subduction Zone (HSZ) is the seismically most active region of Europe. The African plate is subducting beneath the Aegean lithosphere with a relative velocity of 4 cm per year. A detailed picture of the microseismicity of the eastern HSZ was obtained by the recordings of the temporary networks CYCNET (September 2002 - September 2005) and EGELADOS (October 2005 - March 2007). In total, nearly 7000 earthquakes were located with a location uncertainty of less than 20 km. The SE Aegean is dominated by (1) shallow intraplate seismicity within the Aegean plate, by (2) interplate seismicity at the plate contact and by (3) intermediate deep seismicity along the subducting African slab. Strong shallow seismicity in the upper plate is observed along the Ptolemy graben south of Crete extending towards the Karpathos Basin, indicating intense recent deformation of the forearc. In contrary, low shallow seismicity around Rhodes indicates only minor seismic crustal deformation of the upper plate. An almost NS-striking zone of microseismicity has been located, running from the Karpathos basin via the Nisyros volcanic complex towards the EW striking Gökova graben. In the SE Aegean the geometry of the Wadati-Benioff-Zone (WBZ) within the subducting African plate is revealed in detail by the observed microseismicity. Between about 50 to 100 km depth a continuous band of intermediate deep seismicity describes the strongly curved geometry of the slab. From the central to the eastern margin of the HSZ, the dip direction of the WBZ changes from N to NW with a strong increase of the dip angle beneath the eastern Cretan Sea. The margin of the dipping African slab is marked by an abrupt end of the observed WBZ beneath SW Anatolia. Below 100 km depth, the WBZ of the eastern HSZ is dominated by an isolated cluster of intense intermediate deep seismicity (at 100-180 km depth) beneath the Nisyros volcanic complex. It has an extension of about 100x80 km and is build up of 3 parallel

  17. Seismic Tomography.

    ERIC Educational Resources Information Center

    Anderson, Don L.; Dziewonski, Adam M.

    1984-01-01

    Describes how seismic tomography is used to analyze the waves produced by earthquakes. The information obtained from the procedure can then be used to map the earth's mantle in three dimensions. The resulting maps are then studied to determine such information as the convective flow that propels the crustal plates. (JN)

  18. Seismic Symphonies

    NASA Astrophysics Data System (ADS)

    Strinna, Elisa; Ferrari, Graziano

    2015-04-01

    The project started in 2008 as a sound installation, a collaboration between an artist, a barrel organ builder and a seismologist. The work differs from other attempts of sound transposition of seismic records. In this case seismic frequencies are not converted automatically into the "sound of the earthquake." However, it has been studied a musical translation system that, based on the organ tonal scale, generates a totally unexpected sequence of sounds which is intended to evoke the emotions aroused by the earthquake. The symphonies proposed in the project have somewhat peculiar origins: they in fact come to life from the translation of graphic tracks into a sound track. The graphic tracks in question are made up by copies of seismograms recorded during some earthquakes that have taken place around the world. Seismograms are translated into music by a sculpture-instrument, half a seismograph and half a barrel organ. The organ plays through holes practiced on paper. Adapting the documents to the instrument score, holes have been drilled on the waves' peaks. The organ covers about three tonal scales, starting from heavy and deep sounds it reaches up to high and jarring notes. The translation of the seismic records is based on a criterion that does match the highest sounds to larger amplitudes with lower ones to minors. Translating the seismogram in the organ score, the larger the amplitude of recorded waves, the more the seismogram covers the full tonal scale played by the barrel organ and the notes arouse an intense emotional response in the listener. Elisa Strinna's Seismic Symphonies installation becomes an unprecedented tool for emotional involvement, through which can be revived the memory of the greatest disasters of over a century of seismic history of the Earth. A bridge between art and science. Seismic Symphonies is also a symbolic inversion: the instrument of the organ is most commonly used in churches, and its sounds are derived from the heavens and

  19. The potential impact of pneumococcal conjugate vaccine in Africa: Considerations and early lessons learned from the South African experience

    PubMed Central

    Madhi, Shabir A; Nunes, Marta C

    2016-01-01

    The introduction of pneumococcal conjugate vaccine (PCV) into the South African public immunization program since 2009 adopted a novel vaccination schedule of 3 doses at 6, 14 and 40 weeks of age. Over the past 5 y it has been shown that infant PCV immunization in South Africa is effective in reducing the burden of invasive pneumococcal disease (IPD) among HIV-infected and HIV-uninfected children. Furthermore, indirect protection of unvaccinated age-groups (including high risk groups such as HIV-infected adults) against IPD was demonstrated despite the absence of any substantial catch-up campaign of older children. This indirect effect against IPD is corroborated by the temporal reduction in vaccine-serotype colonization among age-groups targeted for PCV immunization as well as unvaccinated HIV-infected and HIV-uninfected adults, which was evident within 2 y of PCV introduction into the immunization program. Vaccine effectiveness has also been demonstrated in children against presumed bacterial pneumonia. The evaluation of the impact of PCV in South Africa, however, remains incomplete. The knowledge gaps remaining include the evaluation of PCV on the incidence of all-cause pneumonia hospitalization among vaccinated and unvaccinated age-groups. Furthermore, ongoing surveillance is required to determine whether there is ongoing replacement disease by non-vaccine serotypes, which could offset the early gains associated with the immunization program in the country. PMID:26317537

  20. Adolescent experiences of violence and relation to violence perpetration beyond young adulthood among an urban sample of Black and African American males.

    PubMed

    Reed, Elizabeth; Lawrence, Danielle A; Santana, M C; Welles, C Seth L; Horsburgh, C Robert; Silverman, Jay G; Rich, John A; Raj, Anita

    2014-02-01

    The purpose of this study is to determine if experiences of physical violence during early and late adolescence (12-21 years) places urban Black males at increased risk for interpersonal violence perpetration beyond young adulthood (30 years and older). Participants of this cross-sectional study were Black and African American men (N = 455) between the ages of 30 and 65 years, recruited from four urban clinical sites in the Northeast. Multivariate logistic regression models were used to analyze the relation of adolescent experiences of violence to: (1) past 6 month street violence involvement and (2) past year intimate partner violence perpetration. Ten percent of the sample reported that they experienced adolescent victimization. Men reporting adolescent victimization were significantly more likely to report past 6-month street violence involvement (Adjusted Odds Ratio (AOR) = 3.2, 95 % CI = 1.7-6.3) and past 6 month intimate partner violence perpetration (AOR = 2.8, 95 % CI = 1.8-5.4) compared to men who did not report such victimization. Study findings suggest that in order to prevent adulthood perpetration of violence, more work is needed to address experiences of victimization among young Black males, particularly violence experienced during adolescence.

  1. Analysis of the seismic signals generated by controlled single-block rockfalls on soft clay shales sediments: the Rioux Bourdoux slope experiment (French Alps).

    NASA Astrophysics Data System (ADS)

    Hibert, Clément; Provost, Floriane; Malet, Jean-Philippe; Bourrier, Franck; Berger, Frédéric; Bornemann, Pierrick; Borgniet, Laurent; Tardif, Pascal; Mermin, Eric

    2016-04-01

    Understanding the dynamics of rockfalls is critical to mitigate the associated hazards but is made very difficult by the nature of these natural disasters that makes them hard to observe directly. Recent advances in seismology allow to determine the dynamics of the largest landslides on Earth from the very low-frequency seismic waves they generate. However, the vast majority of rockfalls that occur worldwide are too small to generate such low-frequency seismic waves and thus these methods cannot be used to reconstruct their dynamics. However, if seismic sensors are close enough, these events will generate high-frequency seismic signals. Unfortunately we cannot yet use these high-frequency seismic records to infer parameters synthetizing the rockfall dynamics as the source of these waves is not well understood. One of the first steps towards understanding the physical processes involved in the generation of high-frequency seismic waves by rockfalls is to study the link between the dynamics of a single block propagating along a well-known path and the features of the seismic signal generated. We conducted controlled releases of single blocks of limestones in a gully of clay-shales (e.g. black marls) in the Rioux Bourdoux torrent (French Alps). 28 blocks, with masses ranging from 76 kg to 472 kg, were released. A monitoring network combining high-velocity cameras, a broadband seismometer and an array of 4 high-frequency seismometers was deployed near the release area and along the travel path. The high-velocity cameras allow to reconstruct the 3D trajectories of the blocks, to estimate their velocities and the position of the different impacts with the slope surface. These data are compared to the seismic signals recorded. As the distance between the block and the seismic sensors at the time of each impact is known, we can determine the associated seismic signal amplitude corrected from propagation and attenuation effects. We can further compare the velocity, the

  2. Active Experiments on Artificial Air Ionization to Check the Physical Mechanism of Air Electrification by Radon in Seismically Active Area

    NASA Astrophysics Data System (ADS)

    Pulinets, S. A.; Pokhmelnykh, L. A.; Domingues, M.; Bisiacchi, G.

    2005-05-01

    The air ionization in troposphere leads to formation of the large charged clusters of the aerosol size due to water molecules attachment to the new formed ions. This process have several consequences leading to the changes of the air conductivity, formation of large scale space charges and large scale electric field, changes of the air temperature and relative humidity. All these effects were observed experimentally within the interval of two weeks before the strong earthquakes such as Colima earthquake in Mexico (M7.8) on 22 of January 2003 or Parkfield earthquake in USA (M6) on 28 of September 2004. In the case of earthquakes the atmosphere electricity modification is ascribed to the radon ionization and the effects are calculated within the frame of the seismo-ionosphere coupling model. But there are very few systematic sources of the radon monitoring, so the real check of the model is better possible within the frame of the controlled active experiment. Such experiments of the artificial ionization were conducted in Mexico using the large wire antennas producing the air ionization by applying the large electric potential (~ 40 kV) to the elevated circular thin wire of ~ 100 m diameter. It was demonstrated that such impact on the atmosphere can create the effects of the meteorological scale producing the artificial clouds (and rains), and even modify the large scale atmospheric formations as typhoons. Results of the theoretical estimations and active experiments will be demonstrated.

  3. Experiences and Perceptions of Interpersonal, Environmental, and Institutional Racism among African-American Students in Psychology Graduate Training.

    ERIC Educational Resources Information Center

    Burrell, Tracey

    Racist incidents that graduate students in psychology may experience can be reflective of Eurocentric values and forces which permeate present institutions. To better understand these forces, the experiences and perceptions of racism as experienced by minority graduate students are explored. Seventeen doctoral students in psychology, who…

  4. Experiences and conceptualizations of sexual debut from the narratives of South African men and women in the context of HIV/AIDS.

    PubMed

    Stern, Erin; Cooper, Diane

    2014-01-01

    Given the pivotal role of first sex in the development of sexual and reproductive health (SRH) practices, there is a need for more contextualised and nuanced understandings of young people's early sexual debut experiences. This study used sexual history narratives to investigate how South African men and women experience and attribute meaning to their sexual debut, and their SRH practices. In light of the gendered disparities among young people's SRH awareness and risk, differences between men and women's narratives of sexual debut were assessed. Fifty sexual history interviews were conducted with men and 25 sexual history interviews with women, with participants purposively sampled from three age categories, a range of cultural and racial backgrounds and urban and rural sites across five provinces. Narrative interviews were designed to elicit stories around participants' early knowledge of sex and sexual experimentation, their range of sexual relationships and SRH practices. The data were analysed using a thematic approach. Participants generally reflected on their early sexual experiences with feelings of inadequacy and disappointment. While men appeared to hold greater decision-making power than women at sexual debut, descriptions of men's early sexual experiences were often characterised by respect, intimacy and vulnerability. Many men attributed the timing of their sexual debut to peer pressure, which typically generated higher social status and rarely included consideration of the need to practice safer sex. Several women felt pressured by their partner to sexually debut, which could have informed their perceptions of men being sexually controlling and aggressive. The study demonstrates the value of a narrative approach for generating insights on young people's sexual debut experiences and SRH practices, and the underlying gendered norms and expectations that shape these. The findings indicate the need for gender transformative HIV interventions to take into

  5. Experiences and conceptualizations of sexual debut from the narratives of South African men and women in the context of HIV/AIDS.

    PubMed

    Stern, Erin; Cooper, Diane

    2014-01-01

    Given the pivotal role of first sex in the development of sexual and reproductive health (SRH) practices, there is a need for more contextualised and nuanced understandings of young people's early sexual debut experiences. This study used sexual history narratives to investigate how South African men and women experience and attribute meaning to their sexual debut, and their SRH practices. In light of the gendered disparities among young people's SRH awareness and risk, differences between men and women's narratives of sexual debut were assessed. Fifty sexual history interviews were conducted with men and 25 sexual history interviews with women, with participants purposively sampled from three age categories, a range of cultural and racial backgrounds and urban and rural sites across five provinces. Narrative interviews were designed to elicit stories around participants' early knowledge of sex and sexual experimentation, their range of sexual relationships and SRH practices. The data were analysed using a thematic approach. Participants generally reflected on their early sexual experiences with feelings of inadequacy and disappointment. While men appeared to hold greater decision-making power than women at sexual debut, descriptions of men's early sexual experiences were often characterised by respect, intimacy and vulnerability. Many men attributed the timing of their sexual debut to peer pressure, which typically generated higher social status and rarely included consideration of the need to practice safer sex. Several women felt pressured by their partner to sexually debut, which could have informed their perceptions of men being sexually controlling and aggressive. The study demonstrates the value of a narrative approach for generating insights on young people's sexual debut experiences and SRH practices, and the underlying gendered norms and expectations that shape these. The findings indicate the need for gender transformative HIV interventions to take into

  6. Testing the Accuracy of Aerial Surveys for Large Mammals: An Experiment with African Savanna Elephants (Loxodonta africana)

    PubMed Central

    Schlossberg, Scott; Chase, Michael J.; Griffin, Curtice R.

    2016-01-01

    Accurate counts of animals are critical for prioritizing conservation efforts. Past research, however, suggests that observers on aerial surveys may fail to detect all individuals of the target species present in the survey area. Such errors could bias population estimates low and confound trend estimation. We used two approaches to assess the accuracy of aerial surveys for African savanna elephants (Loxodonta africana) in northern Botswana. First, we used double-observer sampling, in which two observers make observations on the same herds, to estimate detectability of elephants and determine what variables affect it. Second, we compared total counts, a complete survey of the entire study area, against sample counts, in which only a portion of the study area is sampled. Total counts are often considered a complete census, so comparing total counts against sample counts can help to determine if sample counts are underestimating elephant numbers. We estimated that observers detected only 76% ± SE of 2% of elephant herds and 87 ± 1% of individual elephants present in survey strips. Detectability increased strongly with elephant herd size. Out of the four observers used in total, one observer had a lower detection probability than the other three, and detectability was higher in the rear row of seats than the front. The habitat immediately adjacent to animals also affected detectability, with detection more likely in more open habitats. Total counts were not statistically distinguishable from sample counts. Because, however, the double-observer samples revealed that observers missed 13% of elephants, we conclude that total counts may be undercounting elephants as well. These results suggest that elephant population estimates from both sample and total counts are biased low. Because factors such as observer and habitat affected detectability of elephants, comparisons of elephant populations across time or space may be confounded. We encourage survey teams to

  7. Upper crustal structure from the Santa Monica Mountains to the Sierra Nevada, Southern California: Tomographic results from the Los Angeles Regional Seismic Experiment, Phase II (LARSE II)

    USGS Publications Warehouse

    Lutter, W.J.; Fuis, G.S.; Ryberg, T.; Okaya, D.A.; Clayton, R.W.; Davis, P.M.; Prodehl, C.; Murphy, J.M.; Langenheim, V.E.; Benthien, M.L.; Godfrey, N.J.; Christensen, N.I.; Thygesen, K.; Thurber, C.H.; Simila, G.; Keller, Gordon R.

    2004-01-01

    In 1999, the U.S. Geological Survey and the Southern California Earthquake Center (SCEC) collected refraction and low-fold reflection data along a 150-km-long corridor extending from the Santa Monica Mountains northward to the Sierra Nevada. This profile was part of the second phase of the Los Angeles Region Seismic Experiment (LARSE II). Chief imaging targets included sedimentary basins beneath the San Fernando and Santa Clarita Valleys and the deep structure of major faults along the transect, including causative faults for the 1971 M 6.7 San Fernando and 1994 M 6.7 Northridge earthquakes, the San Gabriel Fault, and the San Andreas Fault. Tomographic modeling of first arrivals using the methods of Hole (1992) and Lutter et al. (1999) produces velocity models that are similar to each other and are well resolved to depths of 5-7.5 km. These models, together with oil-test well data and independent forward modeling of LARSE II refraction data, suggest that regions of relatively low velocity and high velocity gradient in the San Fernando Valley and the northern Santa Clarita Valley (north of the San Gabriel Fault) correspond to Cenozoic sedimentary basin fill and reach maximum depths along the profile of ???4.3 km and >3 km , respectively. The Antelope Valley, within the western Mojave Desert, is also underlain by low-velocity, high-gradient sedimentary fill to an interpreted maximum depth of ???2.4 km. Below depths of ???2 km, velocities of basement rocks in the Santa Monica Mountains and the central Transverse Ranges vary between 5.5 and 6.0 km/sec, but in the Mojave Desert, basement rocks vary in velocity between 5.25 and 6.25 km/sec. The San Andreas Fault separates differing velocity structures of the central Transverse Ranges and Mojave Desert. A weak low-velocity zone is centered approximately on the north-dipping aftershock zone of the 1971 San Fernando earthquake and possibly along the deep projection of the San Gabriel Fault. Modeling of gravity data, using

  8. High Voltage Seismic Generator

    NASA Astrophysics Data System (ADS)

    Bogacz, Adrian; Pala, Damian; Knafel, Marcin

    2015-04-01

    This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes

  9. Deformation experiments under conditions of the blueschist- to eclogite-facies transition: implications for the upper Wadati-Benioff plane of seismicity

    NASA Astrophysics Data System (ADS)

    Incel, S.; Schubnel, A.; Hilairet, N.; Labrousse, L.; Chopin, C.; Renner, J.; Wang, Y.; Ferrand, T. P.; John, T.

    2015-12-01

    Blueschist samples were experimented on a Griggs, a piston-cylinder (PC) and a D-DIA apparatus. Starting materials were sieved powders (<30 μm) from a natural sample collected on Alpine Corsica which initially contained approx. 60 % glaucophane and 40 % lawsonite. After mineral separation, we produced powders with a high (80 % glaucophane, 20 % lawsonite) and a low (30 % glaucophane, 70 % lawsonite) glaucophane content. Samples of cold-pressed powders of the two compositions were deformed in the Griggs and D-DIA apparatus at low temperatures (<550 °C) at which lawsonite is stable but glaucophane should decompose into jadeite and talc, and at high temperatures (up to 850 °C) at which lawsonite dehydrates. Powders were also isostatically annealed at comparable experimental conditions in the PC-apparatus to provide a microstructural reference. The use of synchrotron X-rays during the D-DIA experiments enables us to follow the strain evolution (radiography) while deforming the sample, but also to monitor phase changes in-situ using X-ray diffraction. We also monitored acoustic emissions (AE). Depending on the sample mineralogy and the applied pressure, AEs were either observed at low temperature around 380-420 °C or in a range from 610-850 °C. In some samples AEs were triggered in both ranges. Microstructural observations (SEM, Raman, Microprobe, X-ray tomography) on retrieved samples reveal that samples deformed under deviatoric stress exhibit faults almost exclusively, whereas those under hydrostatic conditions do not. Our preliminary interpretation of stress, strain, microstructural and mineralogical evolution during deformation, is that the two temperature ranges of AE activity correspond to transformational faulting due to the glaucophane breakdown into jadeite and talc and lawsonite dehydration. We interpret these micro-earthquakes as possible laboratory analogs of intermediate depth earthquakes occurring within the upper Wadati-Benioff plane of seismicity

  10. Diagnosed but Not Defeated: The Experiences of African-American Males with Past Histories of Enrollment in Special Education Who Successfully Attend Community College

    ERIC Educational Resources Information Center

    Strickland-Dixon, Kennedi

    2013-01-01

    African-American males are disappearing at alarming rates before our eyes through racially driven practices that secure their position in the penal system and special education. Though many scholars in the field of education have highlighted alarming rates of incarceration and overrepresentation in special education for African-American males,…

  11. The Underrepresentation of African American Women Faculty: A Phenomenological Study Exploring the Experiences of McKnight Doctoral Fellow Alumna Serving in the Professoriate

    ERIC Educational Resources Information Center

    Ferguson, Dionne J.

    2013-01-01

    While African American women have been participating in higher education for more than a century, they remain significantly underrepresented among college and university professors in America. This study was pursued in an attempt to address the underrepresentation of African American women faculty at public and private universities within the…

  12. Integrated verification experiment data collected as part of the Los Alamos National Laboratory`s Source Region program. Appendix F: Regional data from Lawrence Livermore National Laboratory and Sandia National Laboratory Seismic Networks

    SciTech Connect

    Taylor, S.R.

    1993-06-11

    A dataset of regional seismograms assembled for a series of Integrated Verification Experiments conducted by the Los Alamos National Laboratory Source Region program is described. The seismic data has been assembled from networks operated by Lawrence Livermore National Laboratory and Sandia National Laboratory. Examples of the data are shown and basic recording characteristics of the network are described. The seismograms are available on a data tape in SAC format upon request.

  13. The role of fluid pressure in induced vs. triggered seismicity: insights from rock deformation experiments on carbonates

    PubMed Central

    Scuderi, Marco M.; Collettini, Cristiano

    2016-01-01

    Fluid overpressure is one of the primary mechanisms for tectonic fault slip, because fluids lubricate the fault and fluid pressure reduces the effective normal stress that holds the fault in place. However, current models of earthquake nucleation, based on rate- and state- friction laws, imply that stable sliding is favoured by the increase of pore fluid pressure. Despite this controversy, currently, there are only a few studies on the role of fluid pressure under controlled, laboratory conditions. Here, we use laboratory experiments, to show that the rate- and state- friction parameters do change with increasing fluid pressure. We tested carbonate gouges from sub hydrostatic to near lithostatic fluid pressure conditions, and show that the friction rate parameter (a − b) evolves from velocity strengthening to velocity neutral behaviour. Furthermore, the critical slip distance, Dc, decreases from about 90 to 10 μm. Our data suggest that fluid overpressure plays an important role in controlling the mode of fault slip. Since fault rheology and fault stability parameters change with fluid pressure, we suggest that a comprehensive characterization of these parameters is fundamental for better assessing the role of fluid pressure in natural and human induced earthquakes. PMID:27112408

  14. The role of fluid pressure in induced vs. triggered seismicity: insights from rock deformation experiments on carbonates.

    PubMed

    Scuderi, Marco M; Collettini, Cristiano

    2016-04-26

    Fluid overpressure is one of the primary mechanisms for tectonic fault slip, because fluids lubricate the fault and fluid pressure reduces the effective normal stress that holds the fault in place. However, current models of earthquake nucleation, based on rate- and state- friction laws, imply that stable sliding is favoured by the increase of pore fluid pressure. Despite this controversy, currently, there are only a few studies on the role of fluid pressure under controlled, laboratory conditions. Here, we use laboratory experiments, to show that the rate- and state- friction parameters do change with increasing fluid pressure. We tested carbonate gouges from sub hydrostatic to near lithostatic fluid pressure conditions, and show that the friction rate parameter (a - b) evolves from velocity strengthening to velocity neutral behaviour. Furthermore, the critical slip distance, Dc, decreases from about 90 to 10 μm. Our data suggest that fluid overpressure plays an important role in controlling the mode of fault slip. Since fault rheology and fault stability parameters change with fluid pressure, we suggest that a comprehensive characterization of these parameters is fundamental for better assessing the role of fluid pressure in natural and human induced earthquakes.

  15. The role of fluid pressure in induced vs. triggered seismicity: insights from rock deformation experiments on carbonates.

    PubMed

    Scuderi, Marco M; Collettini, Cristiano

    2016-01-01

    Fluid overpressure is one of the primary mechanisms for tectonic fault slip, because fluids lubricate the fault and fluid pressure reduces the effective normal stress that holds the fault in place. However, current models of earthquake nucleation, based on rate- and state- friction laws, imply that stable sliding is favoured by the increase of pore fluid pressure. Despite this controversy, currently, there are only a few studies on the role of fluid pressure under controlled, laboratory conditions. Here, we use laboratory experiments, to show that the rate- and state- friction parameters do change with increasing fluid pressure. We tested carbonate gouges from sub hydrostatic to near lithostatic fluid pressure conditions, and show that the friction rate parameter (a - b) evolves from velocity strengthening to velocity neutral behaviour. Furthermore, the critical slip distance, Dc, decreases from about 90 to 10 μm. Our data suggest that fluid overpressure plays an important role in controlling the mode of fault slip. Since fault rheology and fault stability parameters change with fluid pressure, we suggest that a comprehensive characterization of these parameters is fundamental for better assessing the role of fluid pressure in natural and human induced earthquakes. PMID:27112408

  16. The role of fluid pressure in induced vs. triggered seismicity: insights from rock deformation experiments on carbonates

    NASA Astrophysics Data System (ADS)

    Scuderi, Marco M.; Collettini, Cristiano

    2016-04-01

    Fluid overpressure is one of the primary mechanisms for tectonic fault slip, because fluids lubricate the fault and fluid pressure reduces the effective normal stress that holds the fault in place. However, current models of earthquake nucleation, based on rate- and state- friction laws, imply that stable sliding is favoured by the increase of pore fluid pressure. Despite this controversy, currently, there are only a few studies on the role of fluid pressure under controlled, laboratory conditions. Here, we use laboratory experiments, to show that the rate- and state- friction parameters do change with increasing fluid pressure. We tested carbonate gouges from sub hydrostatic to near lithostatic fluid pressure conditions, and show that the friction rate parameter (a ‑ b) evolves from velocity strengthening to velocity neutral behaviour. Furthermore, the critical slip distance, Dc, decreases from about 90 to 10 μm. Our data suggest that fluid overpressure plays an important role in controlling the mode of fault slip. Since fault rheology and fault stability parameters change with fluid pressure, we suggest that a comprehensive characterization of these parameters is fundamental for better assessing the role of fluid pressure in natural and human induced earthquakes.

  17. "I'm Used to It Now": Experiences of Homophobia among Queer Youth in South African Township Schools

    ERIC Educational Resources Information Center

    Msibi, Thabo

    2012-01-01

    This paper explores how sexually marginalised black high-school students from conservative schooling contexts in KwaZulu-Natal, South Africa, experience schooling. It draws on queer theories through life narratives in presenting findings from a small-scale interventionist project designed by the author. The project involved 14 participants…

  18. Differences in African-American and European-American Students' Engagement with Nanotechnology Experiences: Perceptual Position or Assessment Artifact?

    ERIC Educational Resources Information Center

    Jones, M. Gail; Tretter, Thomas; Paechter, Manuela; Kubasko, Dennis; Bokinsky, Alexandra; Andre, Thomas; Negishi, Atsuko

    2007-01-01

    This study examined middle and high school students' perceptions of a weeklong science experience with nanotechnology and atomic force microscopy. Through an examination of student self assessments and their writing, the study allowed us to examine some of the issues that may contribute to discrepancies that are seen between European-American and…

  19. Seismic properties of the Earth's upper mantle in various geodynamic settings derived from experiments on olivine-orthopyroxene aggregates deformed up to 8 GPa and 1500 °C

    NASA Astrophysics Data System (ADS)

    Soustelle, V.; Manthilake, G.

    2015-12-01

    We present here HP and HT deformation experiments on olivine-orthopyroxene aggregates and discuss the effect of pressure, temperature and composition on the development of olivine CPO and the resulting seismic properties. The experiments were prepared, synthesized, deformed and analysed at the Bayerisches Geoinstitut (University of Bayreuth,Germany). The sample consisted of hot-pressed powders composed of an olivine-orthopyroxene mix (87.5-12.5, 75-25 and 50-50 %) that were then placed in a simple-shear geometry assembly and deformed in a multi-anvil press employing 6 independently acting hydraulic rams at a constant strain-rate of 10-4 s-1 and 3 GPa-1300°C, 5 GPa-1400°C and 8 GPa-1500°C. The achieved shear strain ranged between 1 and 2. The sample were then analysed under SEM-EBSD. At 3 GPa, the observed CPO are similar to those predicted in previous studies, while the one developed at 5 and 8 GPa varies according to the orthopyroxene content: 1) Experiments with 12.5% orthopyroxene display annealing textures and random CPO; 2) the ones with 25% orthopyroxene display B-type olivine CPO consistent with high pressure dislocation creep deformation experiments; and 3) the experiments with 50% orthopyroxenes display A-type olivine CPO consistent with olivine-pyroxene aggregates deformed at high temperature in diffusion creep regime. The resulting seismic properties could therefore explain the seismic anisotropy observations in the mid and lower part of the Earth's upper mantle in different geodynamic contexts. For example, the mantle wedge above subduction which has pyroxene content corresponding to our 25% orthopyroxene experiments and often display the olivine fast-axis normal to the expected mantle flow. On the other hand, a more pristine intraplate mantle most often predict olivine fast-axis parallel to the mantle flow and would have an olivine-pyroxene ratio close to our experiment with 50% orthopyroxene.

  20. Infrasound Generation from the HH Seismic Hammer.

    SciTech Connect

    Jones, Kyle Richard

    2014-10-01

    The HH Seismic hammer is a large, "weight-drop" source for active source seismic experiments. This system provides a repetitive source that can be stacked for subsurface imaging and exploration studies. Although the seismic hammer was designed for seismological studies it was surmised that it might produce energy in the infrasonic frequency range due to the ground motion generated by the 13 metric ton drop mass. This study demonstrates that the seismic hammer generates a consistent acoustic source that could be used for in-situ sensor characterization, array evaluation and surface-air coupling studies for source characterization.

  1. Segmented African Lithosphere Beneath Anatolia Imaged by Teleseismic P-Wave Tomography

    NASA Astrophysics Data System (ADS)

    Biryol, Cemal; Zandt, George; Beck, Susan; Ozacar, Atilla

    2010-05-01

    Anatolia, a part of the Alpine-Himalayan orogenic belt, is shaped by a variety of complex tectonic processes that define the major tectonic provinces across which different deformation regimes exist. Collision related plateau formation dominates the present lithospheric deformation to the east and slab roll-back related back-arc extension takes place in the west. The two zones are connected at the northern part of the region by strike-slip faulting along the right-lateral North Anatolian Fault Zone. Recent seismological studies show that the Eastern Anatolian Plateau (EAP) is supported by hot asthenosphereric material that was emplaced beneath the plateau following the detachment of subducted Arabian lithosphere. The westward continuation of the deeper structure of Anatolia was previously less well constrained due to the lack of geophysical observations. In order to study the deeper lithosphere and mantle structure beneath Anatolia, we used teleseismic P-wave tomography and data from several temporary and permanent seismic networks deployed in the region. A major part of the data comes from the North Anatolian Fault passive seismic experiment (NAF) that consists of 39 broadband seismic stations operated at the north central part of Anatolia between 2005 and 2008. We also used data collected from permanent seismic stations of the National Earthquake Monitoring Center (NEMC) and stations from the Eastern Turkey Seismic Experiment (ETSE). Approximately 34,000 P-wave travel time residuals, measured in multiple frequency bands, are inverted using approximate finite-frequency sensitivity kernels. Our tomograms reveal a fast anomaly that corresponds to the subducted portion of the African lithosphere along the Cyprean Arc. This fast anomaly dips northward beneath central Anatolia with an angle of approximately 45 degrees. However, the anomaly disappears rather sharply to the east beneath the western margin of the EAP and to the west beneath the Isparta Angle. The western

  2. Race, health, and the African Diaspora.

    PubMed

    Spigner, Clarence

    Health inequalities exist throughout the African Diaspora and are viewed in this article as largely color-coded. In developed, developing, and undeveloped nations today, "racial" stratification is consistently reflected in an inability to provide adequate health regardless of national policy or ideology. For instance, African Americans experience less than adequate health care very similar to Blacks in Britain, in spite of each nations differing health systems. Latin America's Africana Negra communities experience poorer health similar to Blacks throughout the Caribbean. The African continent itself is arguably the poorest on earth. A common history of racism correlates with health disparities across the African Diaspora.

  3. Seismic velocity anisotropy and heterogeneity beneath the Mantle Electromagnetic and Tomography Experiment (MELT) region of the East Pacific Rise from analysis of P and S body waves

    USGS Publications Warehouse

    Hammond, W.C.; Toomey, D.R.

    2003-01-01

    We use teleseismic P and S delay times and shear wave splitting measurements to constrain isotropic and anisotropic heterogeneity in the mantle beneath the southern East Pacific Rise (SEPR). The data comprise 462 P and S delay times and 18 shear wave splitting observations recorded during the Mantle Electromagnetic and Tomography (MELT) Experiment. We estimate the mantle melt content (F) and temperature (T) variation from the isotropic velocity variation. Our results indicate that the maximum variation in F beneath our array is between zero and ???1.2%, and maximum variation in T is between zero and ???100 K. We favor an explanation having partial contributions from both T and F. We approximate the seismic anisotropy of the upper mantle with hexagonal symmetry, consistent with the assumption of two dimensionality of mantle flow. Our new tomographic technique uses a nonlinear inversion of P and slow S polarization delay times to simultaneously solve for coupled VP and VS heterogeneity throughout the model and for the magnitude of anisotropy within discrete domains. The domain dimensions and the dip of the anisotropy are fixed for each inversion but are varied in a grid search, obtaining the misfit of the models to the body wave delay data and to split times of vertically propagating S waves. The data misfit and the isotropic heterogeneity are sensitive to domain dimensions and dip of anisotropy. In a region centered beneath the SEPR the best average dip of the hexagonal symmetry axis is horizontal or dipping shallowly (<30??) west. Given the resolution of our data, a subaxial region characterized by vertically aligned symmetry axes may exist but is limited to be <80 km deep. We infer that the mantle flow beneath the SEPR is consistent with shallow asthenospheric return flow from the direction of the South Pacific superswell.

  4. Near-surface Fun with Seismic Data

    NASA Astrophysics Data System (ADS)

    Clapp, M.

    2015-12-01

    What is happening in the near-surface often has a direct effect on human activity. Seismic exploration has routinely targeted geology at depths of kilometers to tens of kilometers. However, these techniques can be applied to answer questions about shallower targets. Several recent experiments demonstrate seismic applicability to near-surface problems. One example is passive seismic monitoring using ambient noise to identify shallow changes and potential hazards in a producing hydrocarbon field. Another example is the use of seismic reflection data from within the water column to determine layering caused by temperature and salinity differences in depth. A third example is identifying historical elevation changes along coast lines using seismic reflection data. These examples show that exploration seismic methods can be effectively used for a variety of near-surface applications.

  5. First Generation U.S.-Born Africans and the Expanded Nigrescence Theory: The Stretching of a Theory for a "Different" African American Experience at a Predominantly White Institution of Higher Education

    ERIC Educational Resources Information Center

    De Walt, Patrick S.

    2009-01-01

    This dissertation explores the applicability of a "stretched" Expanded Nigrescence theory (Cross and Vandiver 2001; NT-E) to the racial identities/attitudes of six First Generation U.S.-Born Africans (FGAs) at a predominantly White institution (PWI). This instrumental case study blended ethnographic techniques and surveys to tell the stories of…

  6. African Aesthetics

    ERIC Educational Resources Information Center

    Abiodun, Rowland

    2001-01-01

    No single traditional discipline can adequately supply answers to the many unresolved questions in African art history. Because of the aesthetic, cultural, historical, and, not infrequently, political biases, already built into the conception and development of Western art history, the discipline of art history as defined and practiced in the West…

  7. "African Connection."

    ERIC Educational Resources Information Center

    Adelman, Cathy; And Others

    This interdisciplinary unit provides students in grades kindergarten through seventh grade an opportunity to understand diversity through a study of Africa as a diverse continent. The project is designed to provide all elementary students with cultural enrichment by exposing them to African music, art, storytelling, and movement. This project can…

  8. Teaching Reflection Seismic Processing

    NASA Astrophysics Data System (ADS)

    Forel, D.; Benz, T.; Pennington, W. D.

    2004-12-01

    Without pictures, it is difficult to give students a feeling for wave propagation, transmission, and reflection. Even with pictures, wave propagation is still static to many. However, when students use and modify scripts that generate wavefronts and rays through a geologic model that they have modified themselves, we find that students gain a real feeling for wave propagation. To facilitate teaching 2-D seismic reflection data processing (from acquisition through migration) to our undergraduate and graduate Reflection Seismology students, we use Seismic Un*x (SU) software. SU is maintained and distributed by Colorado School of Mines, and it is freely available (at www.cwp.mines.edu/cwpcodes). Our approach includes use of synthetic and real seismic data, processing scripts, and detailed explanation of the scripts. Our real data were provided by Gregory F. Moore of the University of Hawaii. This approach can be used by any school at virtually no expense for either software or data, and can provide students with a sound introduction to techniques used in processing of reflection seismic data. The same software can be used for other purposes, such as research, with no additional expense. Students who have completed a course using SU are well equipped to begin using it for research, as well. Scripts for each processing step are supplied and explained to the students. Our detailed description of the scripts means students do not have to know anything about SU to start. Experience with the Unix operating system is preferable but not necessary -- our notes include Computer Hints to help the beginner work with the Unix operating system. We include several examples of synthetic model building, acquiring shot gathers through synthetic models, sorting shot gathers to CMP gathers, gain, 1-D frequency filtering, f-k filtering, deconvolution, semblance displays and velocity analysis, flattening data (NMO), stacking the CMPs, and migration. We use two real (marine) data sets. One

  9. Historical seismicity

    USGS Publications Warehouse

    Dengler, L.

    1992-01-01

    The North Coast region of California in the vicinity of Cape Mendocino is one of the state's most seismically active areas, accounting for 25 percent of seismic energy release in California during the last 50 years. the region is located in a geologically dynamic are surrounding the Mendocino triple junction where three of the Earth's tectonic plates join together ( see preceding article by Sam Clarke). In the historic past the North Coast has been affected by earthquakes occurring on the San Andreas fault system to the south, the Mendocino fault to the southwest, and intraplate earthquakes within both the Gorda and North American plates. More than sixty of these earthquakes have caused damage since the mid-1800's. Recent studies indicate that California's North Coast is also at risk with respect to very large earthquakes (magnitude >8) originating along the Cascadia subduction zone. Although the subduction zone has not generated great earthquakes in historic time, paleoseismic evidence suggests that such earthquakes have been generated by the subduction zone in the recent prehistoric past. 

  10. High resolution seismic data coupled to Multibeam bathymetry of Stromboli island collected in the frame of the Stromboli geophysical experiment: implications with the marine geophysics and volcanology of the Aeolian Arc volcanic complex (Sicily, Southern Tyrrhenian sea, Italy).

    PubMed

    Aiello, Gemma; Di Fiore, Vincenzo; Marsella, Ennio; Passaro, Salvatore

    2014-01-01

    New high resolution seismic data (Subbottom Chirp) coupled to high resolution Multibeam bathymetry collected in the frame of the Stromboli geophysical experiment aimed at recording active seismic data and tomography of the Stromboli Island are here presented. The Stromboli geophysical experiment has been already carried out based on onshore and offshore data acquisition in order to investigate the deep structure and the location of the magma chambers of the Stromboli volcano. A new detailed swath bathymetry of Stromboli Island is here shown and discussed to reconstruct an up-to-date morpho-bathymetry and marine geology of the area compared to the volcanologic setting of the Aeolian Arc volcanic complex. Due to its high resolution the new Digital Terrain Model of the Stromboli Island gives interesting information about the submerged structure of the volcano, particularly about the volcano-tectonic and gravitational processes involving the submarine flanks of the edifice. Several seismic units have been identified based on the geologic interpretation of Subbottom Chirp profiles recorded around the volcanic edifice and interpreted as volcanic acoustic basement pertaining to the volcano and overlying slide chaotic bodies emplaced during its complex volcano-tectonic evolution. They are related to the eruptive activity of Stromboli, mainly poliphasic and to regional geological processes involving the intriguing geology of the Aeolian Arc, a volcanic area still in activity and needing improved research interest. PMID:24860717

  11. High resolution seismic data coupled to Multibeam bathymetry of Stromboli island collected in the frame of the Stromboli geophysical experiment: implications with the marine geophysics and volcanology of the Aeolian Arc volcanic complex (Sicily, Southern Tyrrhenian sea, Italy).

    PubMed

    Aiello, Gemma; Di Fiore, Vincenzo; Marsella, Ennio; Passaro, Salvatore

    2014-01-01

    New high resolution seismic data (Subbottom Chirp) coupled to high resolution Multibeam bathymetry collected in the frame of the Stromboli geophysical experiment aimed at recording active seismic data and tomography of the Stromboli Island are here presented. The Stromboli geophysical experiment has been already carried out based on onshore and offshore data acquisition in order to investigate the deep structure and the location of the magma chambers of the Stromboli volcano. A new detailed swath bathymetry of Stromboli Island is here shown and discussed to reconstruct an up-to-date morpho-bathymetry and marine geology of the area compared to the volcanologic setting of the Aeolian Arc volcanic complex. Due to its high resolution the new Digital Terrain Model of the Stromboli Island gives interesting information about the submerged structure of the volcano, particularly about the volcano-tectonic and gravitational processes involving the submarine flanks of the edifice. Several seismic units have been identified based on the geologic interpretation of Subbottom Chirp profiles recorded around the volcanic edifice and interpreted as volcanic acoustic basement pertaining to the volcano and overlying slide chaotic bodies emplaced during its complex volcano-tectonic evolution. They are related to the eruptive activity of Stromboli, mainly poliphasic and to regional geological processes involving the intriguing geology of the Aeolian Arc, a volcanic area still in activity and needing improved research interest.

  12. Observational study of rock mass response to mining induced seismic events and controlled blasting experiments at deep level gold mines in South Africa

    NASA Astrophysics Data System (ADS)

    Milev, A.; Durrheim, R. J.; Nakatani, M.; Yabe, Y.; Naoi, M. M.; Ogasawara, H.

    2012-12-01

    The strong ground motion generated by mining induced seismic events was studied to characterize the rock mass response and to estimate the site effect on the surface of the underground excavations. A stand-alone instruments, especially designed for recording strong ground motions, were installed underground at a number of deep level gold mines in South Africa. The instruments were recording data at the surface of the stope hangingwalls. A maximum value of 3 m/s was measured. Therefore data were compared to the data recorded in the solid rock by the mine seismic networks to determine the site response. The site response was defined as the ratio of the peak ground velocity measured at the surface of the excavations to the peak ground velocity inferred from the mine seismic data measured in the solid rocks. The site response measured at all mines studied was found to be 9 ± 3 times larger on average. In addition a number of simulated rockbursts were conducted underground in order to estimate the rock mass response when subjected to strong ground motion. The rockbursts were simulated by means of large blasts detonated in solid rock close to the sidewall of a tunnel. The numerical models used in the design of the simulated rockbursts were calibrated by small blasts taking place at each experimental site. A dense array of shock type accelerometers was installed along the blasting wall to monitor the attenuation of the strong ground motion as a function of the distance from the source. The attenuation of peak particle velocity was found to be proportional to R-1.7. In order to improve the understanding of the rock mass behaviour around deep level mining the rate of tilt was monitor and then compare to the seismic ground motion. A good correspondence between the rate of tilt and seismic ground motion was found. The rate of coseismic and aseismic tilt, as well as seismicity recorded by the mine seismic network, are approximately constant until the daily blasting time

  13. Multiple Intimate Partner Violence Experiences: Knowledge, Access, Utilization and Barriers to Utilization of Resources by Women of the African Diaspora

    PubMed Central

    Sabri, Bushra; Huerta, Julia; Alexander, Kamila A.; St.Vil, Noelle M.; Campbell, Jacquelyn C.; Callwood, Gloria B.

    2016-01-01

    Objective This study examined knowledge, access, utilization, and barriers to use of resources among Black women exposed to multiple types of intimate partner violence in Baltimore, Maryland and the U.S. Virgin Islands (USVI). Methods We analyzed quantitative survey data collected by 163 women recruited from primary care, prenatal or family planning clinics in Baltimore and the USVI. In addition we analyzed qualitative data from in-depth interviews with 11 women. Quantitative data were analyzed using descriptive statistics and qualitative data were analyzed using thematic analysis. Results A substantial proportion of Black women with multiple types of violence experiences lacked knowledge of, did not have access to, and did not use resources. Barriers to resource use were identified at the individual, relationship, and community levels. Conclusion There is need for programs to develop awareness, promote access and utilization of resources, and eliminate barriers to resource use among abused Black women. PMID:26548679

  14. Perception, experience, and indigenous knowledge of climate change and variability: the case of Accra, a sub-Saharan African city

    USGS Publications Warehouse

    Codjoe, Samuel N.A.; Owusu, George; Burkett, Virginia

    2014-01-01

    Several recent international assessments have concluded that climate change has the potential to reverse the modest economic gains achieved in many developing countries over the past decade. The phenomenon of climate change threatens to worsen poverty or burden populations with additional hardships, especially in poor societies with weak infrastructure and economic well-being. The importance of the perceptions, experiences, and knowledge of indigenous peoples has gained prominence in discussions of climate change and adaptation in developing countries and among international development organizations. Efforts to evaluate the role of indigenous knowledge in adaptation planning, however, have largely focused on rural people and their agricultural livelihoods. This paper presents the results of a study that examines perceptions, experiences, and indigenous knowledge relating to climate change and variability in three communities of metropolitan Accra, which is the capital of Ghana. The study design is based on a three-part conceptual framework and interview process involving risk mapping, mental models, and individual stressor cognition. Most of the residents interviewed in the three communities of urban Accra attributed climate change to the combination of deforestation and the burning of firewood and rubbish. None of the residents associated climate change with fossil fuel emissions from developed countries. Numerous potential adaptation strategies were suggested by the residents, many of which have been used effectively during past drought and flood events. Results suggest that ethnic residential clustering as well as strong community bonds in metropolitan Accra have allowed various groups and long-settled communities to engage in the sharing and transmission of knowledge of weather patterns and trends. Understanding and building upon indigenous knowledge may enhance the design, acceptance, and implementation of climate change adaptation strategies in Accra and

  15. Seismic sources

    DOEpatents

    Green, M.A.; Cook, N.G.W.; McEvilly, T.V.; Majer, E.L.; Witherspoon, P.A.

    1987-04-20

    Apparatus is described for placement in a borehole in the earth, which enables the generation of closely controlled seismic waves from the borehole. Pure torsional shear waves are generated by an apparatus which includes a stator element fixed to the borehole walls and a rotor element which is electrically driven to rapidly oscillate on the stator element to cause reaction forces transmitted through the borehole walls to the surrounding earth. Longitudinal shear waves are generated by an armature that is driven to rapidly oscillate along the axis of the borehole, to cause reaction forces transmitted to the surrounding earth. Pressure waves are generated by electrically driving pistons that press against opposite ends of a hydraulic reservoir that fills the borehole. High power is generated by energizing the elements for more than about one minute. 9 figs.

  16. 'We are despised in the hospitals': sex workers' experiences of accessing health care in four African countries.

    PubMed

    Scorgie, Fiona; Nakato, Daisy; Harper, Eric; Richter, Marlise; Maseko, Sian; Nare, Prince; Smit, Jenni; Chersich, Matthew

    2013-01-01

    Sex workers in east and southern Africa are exposed to multiple occupational health and safety risks. Detailed understanding of barriers to accessing care would optimise design of improved services for this population. In this study, trained sex workers conducted 55 in-depth interviews and 12 focus group discussions with 106 female, 26 male and 4 transgender sex workers across 6 urban sites in Kenya, Zimbabwe, Uganda and South Africa. Data were analysed thematically, following an interpretive framework. Participants cited numerous unmet health needs, including diagnosis and treatment for sexually transmitted infections and insufficient access to condoms and lubricant. Denial of treatment for injuries following physical assault or rape and general hostility from public-sector providers was common. Resources permitting, many sex workers attended private services, citing higher quality and respect for dignity and confidentiality. Sex workers in southern Africa accessed specialised sex worker clinics, reporting mostly positive experiences. Across sites, participants called for additional targeted services, but also sensitisation and training of public-sector providers. Criminalisation of sex workers and associated stigmatisation, particularly of transgender and male sex workers, hinder HIV-prevention efforts and render access to mainstream healthcare precarious. Alongside law reform, sex worker-led peer outreach work should be strengthened and calls by sex workers for additional targeted services heeded. PMID:23414116

  17. Southern Africa seismic structure and source studies

    NASA Astrophysics Data System (ADS)

    Zhao, Ming

    1998-09-01

    The upper mantle seismic velocity structure beneath southern Africa is investigated using travel time and waveform data. Waveform and travel time data used in this study come mainly from a large mine tremor in South Africa (msb{b} 5.6) recorded on stations of the southern Africa and the Tanzania Broadband Seismic Experiment. Auxiliary data along similar profiles are obtained from other moderate events within eastern and southern Africa. The waveform data from the large tremor show upper mantle triplications for both the 400 and 670-km discontinuities between 18sp° and 27sp° distance. The most notable feature of the data is a large, late P phase that propagates to at least 27sp°. This phase is striking because of its late arrival time (as much as 15 seconds after direct P at 27sp°) and high amplitude relative to the first arrival. Travel times from all available stations are used to invert for the P wave velocity structure down to 800 km depth and S wave velocity structure down to 200 km using the Wiechert-Herglotz (W-H) inversion technique. The P wave velocities from the uppermost mantle down to 300 km are as much as 3% higher than the global average and are slightly slower than the global average between 300 and 400 km depths. The velocity gradient between 300 and 400 km is 0.0015 1/s. The S wave travel time data yield fast velocities above 200-km depth. The S wave velocity structure appears inconsistent with the P wave structure model indicating varying Poisson's ratio in the upper mantle. Little evidence is found for a pronounced upper mantle low velocity zone. Both sharp and gradual-change 400-km discontinuities are favored by the waveform data. The 670-km discontinuity appears as a gradual-change zone. The source mechanism of the mb 5.6 mining tremor itself is important for seismic discrimination and insight into mining tremor sources. Source parameters for this event as well as some other large mining tremors from the South African gold mines are studied

  18. Design of the IPIRG-2 simulated seismic forcing function

    SciTech Connect

    Olson, R.; Scott, P.; Wilkowski, G.

    1996-02-01

    A series of pipe system experiments was conducted in IPIRG-2 that used a realistic seismic forcing function. Because the seismic forcing function was more complex than the single-frequency increasing-amplitude sinusoidal forcing function used in the IPIRG-1 pipe system experiments, considerable effort went into designing the function. This report documents the design process for the seismic forcing function used in the IPIRG-2 pipe system experiments.

  19. How Forgetful are Seismic Waves ?

    NASA Astrophysics Data System (ADS)

    Milkereit, B.

    2005-05-01

    3D surface seismic and vertical seismic profiling (VSP) techniques can be employed to image crustal structures in complex geological settings. The effects of heterogeneities on seismic wave propagation can be described in terms of different propagation regimes (Wu, 1989): quasi-homogeneous for heterogeneities too small to be seen by seismic waves, Rayleigh scattering, Mie scattering and small-angle scattering. These scattering regimes cause characteristic amplitude, phase and travel time fluctuation, which can be used to obtain estimates of scale length. Horizontal resolution of exploration seismic data is often discussed in terms of Fresnel zone. For surface and VSP data, the Fresnel radius increases with increasing depth of investigation. In addition, the lateral resolution is limited by the effective frequency content of the seismic signal. Based on strong contrast in petrophysical data, crustal exploration targets (such as gas-hydrates, permafrost or massive sulfide ores) should make strong P-wave, S-wave and converted wave reflectors against most background velocity models. In the context of realistic geological models, 3D numerical simulations are required to better assess elastic wave interactions with high acoustic impedance targets. In addition, it is important to study the influence of composition and shape of high acoustic impedance targets on the full scattered wavefield through a series of numerical modeling experiments based on the 3D elastic finite-difference (FD) method. Massive sulfide ores consisting of the end-member sulfide minerals pyrite, sphalerite, and galena, which span the full range of observed P- and S- wave velocities and densities in ore rocks, as well as gabbro inclusions, are investigated for different shapes which represent the complex morphologies often observed for ore deposits. 3D FD modeling reveals that large ore deposits lead to a strong and complex scattering response that is often dominated by shear-wave events (Bohlen et al

  20. Obesity and African Americans

    MedlinePlus

    ... Data > Minority Population Profiles > Black/African American > Obesity Obesity and African Americans African American women have the ... ss6304.pdf [PDF | 3.38MB] HEALTH IMPACT OF OBESITY More than 80 percent of people with type ...