Visualizing Culturally Relevant Science Pedagogy Through Photonarratives of Black Middle School Teachers

Science.gov (United States)

Goldston, M. Jenice; Nichols, Sharon

2009-04-01

This study situated in a Southern resegregated Black middle school involved four Black teachers and two White science educators’ use of photonarratives to envision culturally relevant science pedagogy. Two questions guided the study: (1) What community referents are important for conceptualizing culturally relevant practices in Black science classrooms? and (2) How do teachers’ photonarratives serve to open conversations and notions of culturally relevant science practices? The research methodologically drew upon memory-work, Black feminism, critical theory, visual methodology, and narrative inquiry as “portraiture.” Issues of positionality and identity proved to be central to this work, as three luminaries portray Black teachers’ insights about supports and barriers to teaching and learning science. The community referents identified were associated with church and its oral traditions, inequities of the market place in meeting their basic human needs, and community spaces.

Pilgrim Souvenir: Hood of Cherries

Directory of Open Access Journals (Sweden)

Amy Jeffs

2017-06-01

Full Text Available This lead alloy badge from the British Museum represents a medieval hood repurposed as a sack for a harvest of cherries. It measures 38 by 30 millimetres and was cast integrally with its pin and clasp in a three-part mould. When first made, it would have shone like silver. Badges were purchased in their millions by pilgrims between the late twelfth and early sixteenth centuries, as attractive, wearable and cheap souvenirs of their visits to holy sites. By the later Middle Ages badges were also worn as general symbols of devotion, as livery insignia, and as humorous or amorous tokens; which of these categories the “hood of cherries” badge falls into is debatable. Five of them have been found: three in Salisbury, and another in London, while the provenance of the fifth is unknown. Their cataloguers reluctantly associate them with the cult of St Dorothy, whose emblem is a basket of fruit, although Spencer expressed concern that, “a fashionable hood seems far removed from her story.” There are also possible alternative explanations to its meaning, which will be explored here.

Hooded Vulture Necrosyrtes monachus and African White-backed ...

African Journals Online (AJOL)

Basic ecological information is still lacking for many species of African vultures. The Hooded Vulture Necrosyrtes monachus is known as a rare breeding resident in north-eastern South Africa. This study set out to monitor the nests of Hooded Vultures and, secondarily, White-backed Vultures Gyps africanus in the Olifants ...

Visitors to nests of Hooded Vultures Necrosyrtes monachus in ...

African Journals Online (AJOL)

We recommend expanding the Hooded Vulture nest monitoring programme to include more pairs. Keywords: Alopochen aegyptiaca, Chacma Baboon, Egyptian Goose, Hooded Vulture, Kruger-to-Canyons Biosphere Region, Martial Eagle, Necrosyrtes monachus, nest visitors, Papio ursinus, Polemaetus bellicosus ...

Measurements of Capture Efficiency of Range Hoods in Homes

DEFF Research Database (Denmark)

Simone, Angela; Sherman, Max H.; Walker, Iain S.

2015-01-01

mapped the pollution distribution in the room, and showed that the pollutants escape more at the sides of the cooktop. These preliminary results suggest that more measurements should be conducted investigating the capture efficiency at different pollutant source temperature, size and location...... want a range hood to use little energy and have high capture efficiency to minimize the required air flow to capture the cooking pollutants. Currently there are no standards for rating range hoods for capture efficiency In this study, measurements of range hood capture efficiency were made a tight...... kitchen-room built in a laboratory chamber, and a methodology for standardizing measurement of capture efficiency was developed. The results for a wall mounted range hood, showed that up to half of the cooking pollutants were not captured at a flow rate of 230 m3/h. A more detailed set of measurements...

Effect of flow characteristics on ultrafine particle emissions from range hoods.

Science.gov (United States)

Tseng, Li-Ching; Chen, Chih-Chieh

2013-08-01

In order to understand the physical mechanisms of the production of nanometer-sized particulate generated from cooking oils, the ventilation of kitchen hoods was studied by determining the particle concentration, particle size distribution, particle dimensions, and hood's flow characteristics under several cooking scenarios. This research varied the temperature of the frying operation on one cooking operation, with three kinds of commercial cooking oils including soybean oil, olive oil, and sunflower oil. The variations of particle concentration and size distributions with the elevated cooking oil temperatures were presented. The particle concentration increases as a function of temperature. For oil temperatures ranging between 180°C and 210°C, a 5°C increase in temperature increased the number concentration of ultrafine particles by 20-50%. The maximum concentration of ultrafine particles was found to be approximately 6 × 10(6) particles per cm(3) at 260°C. Flow visualization techniques and particle distribution measurement were performed for two types of hood designs, a wall-mounted range hood and an island hood, at a suction flow rate of 15 m(3) min(-1). The flow visualization results showed that different configurations of kitchen hoods induce different aerodynamic characteristics. By comparing the results of flow visualizations and nanoparticle measurements, it was found that the areas with large-scale turbulent vortices are more prone to dispersion of ultrafine particle leakage because of the complex interaction between the shear layers and the suction movement that results from turbulent dispersion. We conclude that the evolution of ultrafine particle concentration fluctuations is strongly affected by the location of the hood, which can alter the aerodynamic features. We suggest that there is a correlation between flow characteristics and amount of contaminant leakage. This provides a comprehensive strategy to evaluate the effectiveness of kitchen hoods

Effects of boundary-layer separation controllers on a desktop fume hood.

Science.gov (United States)

Huang, Rong Fung; Chen, Jia-Kun; Hsu, Ching Min; Hung, Shuo-Fu

2016-10-02

A desktop fume hood installed with an innovative design of flow boundary-layer separation controllers on the leading edges of the side plates, work surface, and corners was developed and characterized for its flow and containment leakage characteristics. The geometric features of the developed desktop fume hood included a rearward offset suction slot, two side plates, two side-plate boundary-layer separation controllers on the leading edges of the side plates, a slanted surface on the leading edge of the work surface, and two small triangular plates on the upper left and right corners of the hood face. The flow characteristics were examined using the laser-assisted smoke flow visualization technique. The containment leakages were measured by the tracer gas (sulphur hexafluoride) detection method on the hood face plane with a mannequin installed in front of the hood. The results of flow visualization showed that the smoke dispersions induced by the boundary-layer separations on the leading edges of the side plates and work surface, as well as the three-dimensional complex flows on the upper-left and -right corners of the hood face, were effectively alleviated by the boundary-layer separation controllers. The results of the tracer gas detection method with a mannequin standing in front of the hood showed that the leakage levels were negligibly small (≤0.003 ppm) at low face velocities (≥0.19 m/s).

Ethanol intake and 3H-serotonin uptake I: A study in Fawn-Hooded rats

International Nuclear Information System (INIS)

Daoust, M.; Compagnon, P.; Legrand, E.; Boucly, P.

1991-01-01

Ethanol intake and synaptosomal 3 H-serotonin uptake were studied in male Fawn-Hooded and Sprague-Dawley rats. Fawn-Hooded rats consumed more alcohol and more water than Sprague-Dawley rats. Plasma alcohol levels of Sprague-Dawley rats were not detectable but were about 5 mg/dl in Fawn-Hooded rats. Ethanol intake increased the Vmax of serotonin uptake in Fawn-Hooded rats in hippocampus and cortex, but not in thalamus. In Fawn-Hooded rats, serotonin uptake (Vmax) was higher than in Sprague-Dawley rats cortex. Ethanol intake reduced the Vmax of serotonin uptake in Fawn-Hooded rats in hippocampus and cortex. In cortex, the carrier affinity for serotonin was increased in alcoholized Fawn-Hooded rats. These results indicate that synaptosomal 3 H-serotonin uptake is affected by ethanol intake. In Fawn-Hooded rats, high ethanol consumption is associated with high serotonin uptake. In rats presenting high serotonin uptake, alcoholization reduces 3 H-serotonin internalization in synaptosomes, indicating a specific sensitivity to alcohol intake of serotonin uptake system

Minimum acceptable face velocities of laboratory fume hoods and guidelines for their classification

International Nuclear Information System (INIS)

Bolton, N.E.; Porter, W.E.; Alcorn, S.P.; Everett, W.S.; Hunt, J.B.; Morehead, J.F.; Higdon, H.F.

1978-06-01

Data developed to support the requirement of a 100 LFM minimum face velocity requirement for laboratory fume hoods are summarized. Also included is a description of the Y-12 test hood as well as guidelines for a hood classification scheme

Effect of internal elements of the steam turbine exhaust hood on losses

Directory of Open Access Journals (Sweden)

Tajč Ladislav

2012-04-01

Full Text Available The document deals with the flow in the exhaust hood of a single flow steam turbine. The effect of the shape of the external case of the hood and the position and dimensions of the internal reinforcements on the energy loss coefficient is evaluated. Using this coefficient, it is possible to determine the gained or lost output in the diffuser and the entire exhaust hood at a known flow and efficiency of the last stage. Flow research in the exhaust hood was performed especially using numeric simulations; some variants were verified experimentally in the aerodynamic wind tunnel.

Hood River production program monitoring and evaluation. Report A: Hood River and Pelton Ladder evaluation studies. Annual report for 1996

International Nuclear Information System (INIS)

Olsen, E.A.; French, R.A.

1996-01-01

In 1992, the Northwest Power Planning Council approved the Hood River and Pelton Ladder master plans within the framework of the Columbia River Basin Fish and Wildlife Program. The master plans define an approach for implementing a hatchery supplementation program in the Hood River subbasin. The hatchery program, as defined in the master plans, is called the Hood River Production Program (HRPP). The HRPP will be implemented at a reduced hatchery production level until (1) the construction of all proposed hatchery facilities has been completed and (2) numbers of returning wild jack and adult fish are sufficient to meet broodstock collection goals. It is anticipated that construction on the hatchery production facilities will be completed by the spring of 1998. The HRPP is jointly implemented by the Oregon Department of Fish and Wildlife (ODFW) and the Confederated Tribes of the Warm Springs (CTWS) Reservation

Field-trip guide to Mount Hood, Oregon, highlighting eruptive history and hazards

Science.gov (United States)

Scott, William E.; Gardner, Cynthia A.

2017-06-22

This guidebook describes stops of interest for a geological field trip around Mount Hood volcano. It was developed for the 2017 International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) Scientific Assembly in Portland, Oregon. The intent of this guidebook and accompanying contributions is to provide an overview of Mount Hood, including its chief geologic processes, magmatic system, eruptive history, local tectonics, and hazards, by visiting a variety of readily accessible localities. We also describe coeval, largely monogenetic, volcanoes in the region. Accompanying the field-trip guidebook are separately authored contributions that discuss in detail the Mount Hood magmatic system and its products and behavior (Kent and Koleszar, this volume); Mount Hood earthquakes and their relation to regional tectonics and the volcanic system (Thelen and Moran, this volume); and young surface faults cutting the broader Mount Hood area whose extent has come to light after acquisition of regional light detection and ranging coverage (Madin and others, this volume).The trip makes an approximately 175-mile (280-kilometer) clockwise loop around Mount Hood, starting and ending in Portland. The route heads east on Interstate 84 through the Columbia River Gorge National Scenic Area. The guidebook points out only a few conspicuous features of note in the gorge, but many other guides to the gorge are available. The route continues south on the Mount Hood National Scenic Byway on Oregon Route 35 following Hood River, and returns to Portland on U.S. Highway 26 following Sandy River. The route traverses rocks as old as the early Miocene Eagle Creek Formation and overlying Columbia River Basalt Group of middle Miocene age, but chiefly lava flows and clastic products of arc volcanism of late Miocene to Holocene age.

Finite element analysis of car hood for impact test by using ...

African Journals Online (AJOL)

Finite element analysis of car hood for impact test by using solidworks software ... high safety and at the same time can be built according to market demands. ... Keywords: finite element analysis; impact test; Solidworks; automation, car hood.

Hood River and Pelton Ladder monitoring and evaluation project and Hood River fish habitat project : annual progress report 1999-2000.; ANNUAL

International Nuclear Information System (INIS)

Lambert, Michael B.; McCanna, Joseph P.; Jennings, Mick

2001-01-01

The Hood River subbasin is home to four species of anadromous salmonids: chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), steelhead (Oncorhynchus mykiss), and sea run cutthroat trout (Salmo clarki). Indigenous spring chinook salmon were extirpated during the late 1960's. The naturally spawning spring chinook salmon currently present in the subbasin are progeny of Deschutes stock. Historically, the Hood River subbasin hatchery steelhead program utilized out-of-basin stocks for many years. Indigenous stocks of summer and winter steelhead were listed in March 1998 by National Marine Fisheries Service (NMFS) under the Endangered Species Act (ESA) as a ''Threatened'' Species along with similar genetically similar steelhead in the Lower Columbia Basin. This annual report summarizes work for two consecutive contract periods: the fiscal year (FY) 1999 contract period was 1 October, 1998 through 30 September, 1999 and 1 October, 1999 through 30 September, 2000 for FY 2000. Work implemented during FY 1999 and FY 2000 included (1) acclimation of hatchery spring chinook salmon and hatchery summer and winter steelhead smolts, (2) spring chinook salmon spawning ground surveys on the West Fork Hood River (3) genetic analysis of steelhead and cutthroat[contractual service with the ODFW], (4) Hood River water temperature studies, (5) Oak Springs Hatchery (OSH) and Round Butte Hatchery (RBH) coded-wire tagging and clipping evaluation, (6) preparation of the Hood River Watershed Assessment (Coccoli et al., December 1999) and the Fish Habitat Protection, Restoration, and Monitoring Plan (Coccoli et al., February 2000), (7) project implementation of early action habitat protection and restoration projects, (8) Pelton Ladder evaluation studies, (9) management oversight and guidance to BPA and ODFW engineering on HRPP facilities, and (10) preparation of an annual report summarizing project objectives for FY 1999 and FY 2000

Removal (and attempted removal) of material from a Hooded Vulture ...

African Journals Online (AJOL)

Relatively little is documented about nest material theft in vultures. We used camera traps to monitor Hooded Vulture Necrosyrtes monachus nests for a year. We report camera trap photographs of a starling Lamprotornis sp. removing what appeared to be dung from an inactive Hooded Vulture nest on Cleveland Game ...

Analysis of heat transfer and contaminant transport in fume hoods

International Nuclear Information System (INIS)

Pathanjali, C.; Rahman, M.M.

1996-01-01

The paper presents the analysis of three-dimensional flow patterns and the associated heat and mass transfer mechanisms in a fume hood enclosure. The flow enters the hood through the front window opening (positive x-direction) and leaves the cupboard through an opening on the top of the hood (positive z-direction). The flow was assumed to be fully turbulent. The flow pattern for different sash openings were studied. The flow pattern around an object located at the bottom of the hood was studied for different locations of the object. It was found that air entering the hood proceeds directly to the back wall, impinges it and turns upward toward the top wall and exits through the outlet. The flow finds its way around any object forming a recirculating region at its training surface. With an increase in the sash opening, the velocity becomes higher and the fluid traces the path to the outlet more quickly. The volume occupied by recirculating flow decreases with increase in sash opening. Both temperature and concentration were found to be maximum near the source and gradually decreased as the heated air or gaseous contaminant entrained with incoming air. The local concentration decreased with increase in sash opening area. The results will be very useful to design experiments with optimum sash opening providing adequate disposal of contaminants with minimum use of conditioned air inside the room

"Ameeriklane" Robin Hood / Timo Diener

Index Scriptorium Estoniae

Diener, Timo

2005-01-01

Mängufilmi "Robin Hood : varaste prints" võtetest. Režissöör Kevin Reynolds, peaosas Kevin Costner, USA 1991. Järg: Teleleht nr. 14, 11. aprill 2005, lk. 38 : ill ja Teleleht nr. 15, 18. aprill 2005, lk. 38 : ill

The Influence of Inlet Asymmetry on Steam Turbine Exhaust Hood Flows.

Science.gov (United States)

Burton, Zoe; Hogg, Simon; Ingram, Grant L

2014-04-01

It has been widely recognized for some decades that it is essential to accurately represent the strong coupling between the last stage blades (LSB) and the diffuser inlet, in order to correctly capture the flow through the exhaust hoods of steam turbine low pressure cylinders. This applies to any form of simulation of the flow, i.e., numerical or experimental. The exhaust hood flow structure is highly three-dimensional and appropriate coupling will enable the important influence of this asymmetry to be transferred to the rotor. This, however, presents challenges as the calculation size grows rapidly when the full annulus is calculated. The size of the simulation means researchers are constantly searching for methods to reduce the computational effort without compromising solution accuracy. However, this can result in excessive computational demands in numerical simulations. Unsteady full-annulus CFD calculation will remain infeasible for routine design calculations for the foreseeable future. More computationally efficient methods for coupling the unsteady rotor flow to the hood flow are required that bring computational expense within realizable limits while still maintaining sufficient accuracy for meaningful design calculations. Research activity in this area is focused on developing new methods and techniques to improve accuracy and reduce computational expense. A novel approach for coupling the turbine last stage to the exhaust hood employing the nonlinear harmonic (NLH) method is presented in this paper. The generic, IP free, exhaust hood and last stage blade geometries from Burton et al. (2012. "A Generic Low Pressure Exhaust Diffuser for Steam Turbine Research,"Proceedings of the ASME Turbo Expo, Copenhagen, Denmark, Paper No. GT2012-68485) that are representative of modern designs, are used to demonstrate the effectiveness of the method. This is achieved by comparing results obtained with the NLH to those obtained with a more conventional mixing

Hood River Production Program Review, Final Report 1991-2001.

Energy Technology Data Exchange (ETDEWEB)

Underwood, Keith; Chapman, Colin; Ackerman, Nicklaus

2003-12-01

This document provides a comprehensive review of Bonneville Power Administration (BPA) funded activities within the Hood River Basin from 1991 to 2001. These activities, known as the Hood River Production Program (HRPP), are intended to mitigate for fish losses related to operation of federal dams in the Columbia River Basin, and to contribute to recovery of endangered and/or threatened salmon and steelhead, as directed by Nation Oceanic and Atmospheric Administration - Fisheries (NOAA Fisheries). The Environmental Impact Statement (EIS) for the HRPP, which authorized BPA to fund salmon and steelhead enhancement activities in the Hood River Basin, was completed in 1996 (BPA 1996). The EIS specified seven years of monitoring and evaluation (1996-2002) after program implementation to determine if program actions needed modification to meet program objectives. The EIS also called for a program review after 2002, that review is reported here.

Determination of the internal exposure hazard from plutonium work in an open front hood

Science.gov (United States)

Olson, Cheryl Lynn

Work with hazardous substances, such as radioactive material, can be done safely when engineered controls are used to maintain the worker effective dose below the International Commission on Radiological Protection ICRP 60 recommendation of 0.02 Sv/year and reduce the worker exposure to material to as low as reasonably achievable (ALARA). A primary engineered control used at a Los Alamos National Laboratory facility is the open-front hood. An open-front hood, also known as an open-front box, is a laboratory containment box that is fully enclosed except for a 15-cm opening along the front of the box. This research involved collection of the aerosol escaping an open-front hood while PuO2 sample digestion was simulated. Sodium chloride was used as a surrogate to mimic the behavior of PuO2. The NaCl aerosol was binned as a function of median aerodynamic diameter using a Micro-orifice Uniform Deposit Impactor (MOUDI, MSP Corporation, Shoreview, MN) cascade impactor. Using neutron activation analysis (NAA) to measure the mass of material in each of the nine bins of the MOUDI, the mass median diameter of the escaping aerosol was determined. Using the mass median diameter and the total mass of the particle distribution, dose was calculated using ICRP 60 methodology. Experimental conditions mimicked a stationary worker and a worker moving her hands in and out of the open front hood. Measurements were also done in the hood for comparison. The effect of the hands moving in and out of the box was modeled. Information necessary for Computational Fluid Dynamics (CFD) modeling is given, such as volumetric flow rates out of the open front hood and into the experimental room, detailed sketches of the experimental set-up, and energy provided by the hot plate and worker. This research is unique as it measures particle size distribution from routine working conditions. Current research uses tracer gases or describes non-routine conditions. It is important to have results that mimic

Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume hoods

International Nuclear Information System (INIS)

Tsai, Su-Jung; Ada, Earl; Isaacs, Jacqueline A.; Ellenbecker, Michael J.

2009-01-01

Manual handling of nanoparticles is a fundamental task of most nanomaterial research; such handling may expose workers to ultrafine or nanoparticles. Recent studies confirm that exposures to ultrafine or nanoparticles produce adverse inflammatory responses in rodent lungs and such particles may translocate to other areas of the body, including the brain. An important method for protecting workers handling nanoparticles from exposure to airborne nanoparticles is the laboratory fume hood. Such hoods rely on the proper face velocity for optimum performance. In addition, several other hood design and operating factors can affect worker exposure. Handling experiments were performed to measure airborne particle concentration while handling nanoparticles in three fume hoods located in different buildings under a range of operating conditions. Nanoalumina and nanosilver were selected to perform handling experiments in the fume hoods. Air samples were also collected on polycarbonate membrane filters and particles were characterized by scanning electron microscopy. Handling tasks included transferring particles from beaker to beaker by spatula and by pouring. Measurement locations were the room background, the researcher's breathing zone and upstream and downstream from the handling location. Variable factors studied included hood design, transfer method, face velocity/sash location and material types. Airborne particle concentrations measured at breathing zone locations were analyzed to characterize exposure level. Statistics were used to test the correlation between data. The test results found that the handling of dry powders consisting of nano-sized particles inside laboratory fume hoods can result in a significant release of airborne nanoparticles from the fume hood into the laboratory environment and the researcher's breathing zone. Many variables were found to affect the extent of particle release including hood design, hood operation (sash height, face velocity

Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume hoods

Energy Technology Data Exchange (ETDEWEB)

Tsai, Su-Jung, E-mail: candace.umass@gmail.com; Ada, Earl [University of Massachusetts Lowell, NSF Center for High-rate Nanomanufacturing (CHN) (United States); Isaacs, Jacqueline A. [Northeastern University, NSF Center for High-rate Nanomanufacturing (CHN) (United States); Ellenbecker, Michael J. [University of Massachusetts Lowell, NSF Center for High-rate Nanomanufacturing (CHN) (United States)

2009-01-15

Manual handling of nanoparticles is a fundamental task of most nanomaterial research; such handling may expose workers to ultrafine or nanoparticles. Recent studies confirm that exposures to ultrafine or nanoparticles produce adverse inflammatory responses in rodent lungs and such particles may translocate to other areas of the body, including the brain. An important method for protecting workers handling nanoparticles from exposure to airborne nanoparticles is the laboratory fume hood. Such hoods rely on the proper face velocity for optimum performance. In addition, several other hood design and operating factors can affect worker exposure. Handling experiments were performed to measure airborne particle concentration while handling nanoparticles in three fume hoods located in different buildings under a range of operating conditions. Nanoalumina and nanosilver were selected to perform handling experiments in the fume hoods. Air samples were also collected on polycarbonate membrane filters and particles were characterized by scanning electron microscopy. Handling tasks included transferring particles from beaker to beaker by spatula and by pouring. Measurement locations were the room background, the researcher's breathing zone and upstream and downstream from the handling location. Variable factors studied included hood design, transfer method, face velocity/sash location and material types. Airborne particle concentrations measured at breathing zone locations were analyzed to characterize exposure level. Statistics were used to test the correlation between data. The test results found that the handling of dry powders consisting of nano-sized particles inside laboratory fume hoods can result in a significant release of airborne nanoparticles from the fume hood into the laboratory environment and the researcher's breathing zone. Many variables were found to affect the extent of particle release including hood design, hood operation (sash height, face

Sexual aggression by intruders in hooded crow Corvus cornix

OpenAIRE

Zduniak, Piotr; Kosicki, Jakub Z.; Yosef, Reuven

2015-01-01

The hooded crow Corvus cornix is a west Palaearctic, solitary nesting, monogamous corvid. In the breeding season, populations are characterized by a social organization wherein breeding pairs are territorial and non-breeding individuals, called floaters, live in flocks. During a study of the breeding ecology of the hooded crow, conducted in a protected flooded area, we monitored nests with video cameras. We recorded two separate incidents when intruders attacked a female at the nest. We belie...

Relationship of sex, achievement, and science self-concept to the science career preferences of black students

Science.gov (United States)

Jacobowitz, Tina

Science career preferences of junior high school-aged students, while not stable predictors of ultimate career choice, do serve to direct and maintain individuals along the paths to careers in science. In this study, factors relevant to science career preferences of black eighth grade students were investigated. This issue is of particular import to blacks since they are severely underrepresented in the scientific fields. The sample consisted of 113 males and 148 females in an inner city junior high school. The Science Career Preference Scale, the Peabody Picture Vocabulary Test, and the Self-Concept of Ability Scale (Form B-Science) were administered. Mathematics and science grades were obtained from class rating sheets. Treatment of the data involved multiple regression analysis according to a hierarchical model. Results showed that of all the independent variables, sex was the strongest predictor of science career preferences, accounting for 25% of the criterion variance. The findings suggest that early adolescent science career preferences are related more to interests that are consonant with sex-role considerations than realistic assessment of mathematics or science achievement.

Black males' self-perceptions of academic ability and gifted potential in advanced science classes

Science.gov (United States)

Rascoe, Barbara; Monroe Atwater, Mary

2005-10-01

The purpose of this research effort was to examine Black male students' self-perceptions of academic ability and gifted potential in science. The purposeful sample consisted of nine Black males between the ages of 14 and 18 years. Four categories of self-perceptions of academic ability and gifted potential emerged from the data. These included: (a) gifted high achievers; (b) gifted could do better high achievers; (c) gifted could do better situational nonachievers; and (d) gifted could do better underachievers. Science teachers' influences that referenced participants' academic achievement pointed to validation. Participants' perceptions regarding how science teachers' influenced their academic performance focused on science teachers' content knowledge. Power dynamics germane to Black male participants' value or worth that directed their efforts in science learning environments are discussed. Implications are posited for science teaching, science education programs, and future research. This research endeavor was based on two premises. The first premise is that Black males' self-perceptions of academic ability affect their science academic achievement. The second premise is that, given parental, peer, and community influences, science teachers have considerable influence on students' self-perceptions of academic ability. However, the focus of this research was not on parental influences, peer influences, or any potential influences that participants' communities may have on their academic achievement.

Fort Hood Building and Landscape Inventory with WWII and Cold War Context

Science.gov (United States)

2007-03-01

barracks, 1970s (NARA)........................................................... 112 Figure 37. Palmer Movie Theater (NARA...revised 1953) showing layout of Hood Village and trailer park (Fort Hood...arms ammunition storage building #92012 (ERDC-CERL, 2004). ......... 260 Figure 163: Radio reception building #92063 (ERDC-CERL, 2004

Hood River and Pelton Ladder Evaluation Studies, Annual Report 2000-2001.

Energy Technology Data Exchange (ETDEWEB)

Olsen, Erik

2009-09-01

The Bonneville Power Administration (BPA) funded the development of two master plans which outline the rationale, and general approach, for implementing a defined group of projects that are an integral part of a comprehensive watershed goal to 'Protect, enhance and restore wild and natural populations of anadromous and resident fish within the Hood River Subbasin'. The Hood River Production Master Plan and the Pelton Ladder Master Plan were completed in 1991 and subsequently approved by the Northwest Power Planning Council in 1992. Action items identified in the two master plans, as well as in a later document entitled 'Hood River/Pelton Ladder Master Agreement' (ODFW and CTWSRO Undated), are designed to achieve two biological fish objectives: (1) to increase production of wild summer and winter steelhead (Oncorhynchus mykiss) to levels commensurate with the subbasins current carrying capacity and (2) re-establishing a self-sustaining population of spring chinook salmon (Oncorhynchus tshawytscha). Numerical fish objectives for subbasin escapement, spawner escapement, and subbasin harvest are defined for each of these species in Coccoli (2000). Several projects are presently funded by the BPA to achieve the Hood River subbasin's numerical fish objectives for summer and winter steelhead and spring chinook salmon. They include BPA project numbers 1998-021-00 (Hood River Fish Habitat), 1998-053-03 (Hood River Production Program - CTWSRO: M&E), 1998-053-07 (Parkdale Fish Facility), 1998-053-08 (Powerdale/Oak Springs O&M), and 1998-053-12 (Hood River Steelhead Genetics Study). Collectively, they are implemented under the umbrella of what has come to be defined as the Hood River Production Program (HRPP). The HRPP is jointly implemented by the Oregon Department of Fish and Wildlife (ODFW) and The Confederated Tribes of the Warm Springs Reservation of Oregon (CTWSRO). Strategies for achieving the HRPP's biological fish objectives for the Hood

Staying in the Hood: Black Lesbian and Transgender Women and Identity Management in North Philadelphia.

Science.gov (United States)

Brooks, Siobhan

2016-12-01

The concept Don't Ask, Don't Tell regarding Black LGBT sexuality in Black communities has been an acceptable form of identity management for Black LGBT people. In other words, Black LGBT people are accepted as long as they are not vocal about their sexuality. However, this is changing with the issue of gay marriage, which is creating a space where Black LGBT people are more open about their gender identity and sexuality in heterosexual Black spaces. This new form of openness allows Black LGBT people to "stay in" their communities, as opposed to coming out. In this article I examine how Black LGBT women in North Philadelphia stay in their communities: being politically active regarding LGBT issues, disengaging from LGBT issues, passing, and educating straight Black people about issues affecting the Black LGBT community. I conclude with implications of staying in and intersectionality among Black heterosexual and LGBT women fighting for social change.

Hood River Passive House

Energy Technology Data Exchange (ETDEWEB)

Hales, David [BA-PIRC, Spokane, WA (United States)

2014-01-01

The Hood River Passive Project was developed by Root Design Build of Hood River Oregon using the Passive House Planning Package (PHPP) to meet all of the requirements for certification under the European Passive House standards. The Passive House design approach has been gaining momentum among residential designers for custom homes and BEopt modeling indicates that these designs may actually exceed the goal of the U.S. Department of Energy's (DOE) Building America program to "reduce home energy use by 30%-50% (compared to 2009 energy codes for new homes). This report documents the short term test results of the Shift House and compares the results of PHPP and BEopt modeling of the project. The design includes high R-Value assemblies, extremely tight construction, high performance doors and windows, solar thermal DHW, heat recovery ventilation, moveable external shutters and a high performance ductless mini-split heat pump. Cost analysis indicates that many of the measures implemented in this project did not meet the BA standard for cost neutrality. The ductless mini-split heat pump, lighting and advanced air leakage control were the most cost effective measures. The future challenge will be to value engineer the performance levels indicated here in modeling using production based practices at a significantly lower cost.

The Effect of Condensing Steam Turbine Exhaust Hood Body Geometry on Exhaust Performance Efficiency

Science.gov (United States)

Gribin, V. G.; Paramonov, A. N.; Mitrokhova, O. M.

2018-06-01

The article presents data from combined numerical and experimental investigations of the effect that the overall dimensions of the exhaust hood of a steam turbine with an underslung condenser has on the aerodynamic losses in the hood. Owing to the properly selected minimum permissible overall dimensions of the exhaust hood, more efficient operation of this turbine component is achieved, better vibration stability of the turbine set shaft line is obtained, and lower costs are required for arranging the steam turbine plant in the turbine building. Experiments have shown that the main overall dimensions of the hood body have a determining effect on the exhaust hood flow path profile and on its aerodynamic performance. Owing to properly selected ratios between the exhaust hood body main sizes without a diffuser, a total loss coefficient equal to approximately unity has been obtained. By using an axial-radial diffuser, the energy loss can be decreased by 30-40% depending on the geometrical parameters and level of velocities in the inlet section of a hood having the optimal overall dimensions. By using the obtained results, it becomes possible to evaluate the overall dimensions necessary for achieving the maximal aerodynamic hood efficiency and, as a consequence, to obtain better technical and economic indicators of the turbine plant as a whole already at the initial stage of its designing. If a need arises to select overall dimensions smaller than their optimal values, the increase of energy loss can be estimated using the presented dependences. The cycle of investigations was carried out on the experimental setups available in the fundamental research laboratory of the Moscow Power Engineering Institute National University's Department of Steam and Gas Turbines with due regard to the operating parameters and similarity criteria.

The Influence of the Bed with a Semiopen Hood on Bacteria Removal in a Negative-Pressure Isolation Room

Directory of Open Access Journals (Sweden)

Jeng-Min Huang

2014-06-01

Full Text Available This study numerically investigates the influence of a sickbed with a semiopened hood on bacteria removal in a negative-pressure isolation room. The parameters include air change rate, lying style, the length and height of hood, flow rate allotments, and the positions of outlets. The results show that the hood has excellent effect on the removal of contaminated air, which is much better than the case without hood. The flow field of patient's face up cough is very different from face side cough, and the contaminated air cannot be removed properly through one air outlet. There are three outlets on the hood, set straight above the patient's face and at both sides. The allotment of the exhaust flow rate of the upper outlet to that of side outlets is suggested to be 4: 6. When the total air change rate is above 6 ACH, the hood length has slight influence on pollutant removal. The increase of hood height has a negative impact when the patient coughs lying on back. When the side exhaust flow rate is high, the hood height has a slight impact for face side cough. The recommended air change rate for the negative-pressure ward with sickbed hood is above 5 ACH.

Biological Assessment of the Effects of Military Associated Activities on Endangered Species at Fort Hood, Texas

Science.gov (United States)

1992-12-01

monographing the genus Croton. Dr. Joe Allen Farmer published a dissertation on the species in 1962. Studies on the Fort Hood population have begun under...Woodhouse, S.W., "Descriptions of New Species of the Genus Vireo, VieilL, and Zonorrichia, Swains," Proceeding of the Academy of Natural Sciences of...sinuata Skunkbush Saumac Rhus aroma tica Texas Oak Quercus texazza Texas Persimmon, Diospyros texana Texas Ashe Fraxinus texensis Virginia Creeper Paz

Hood River Conservation Project load analysis

Energy Technology Data Exchange (ETDEWEB)

Stovall, T.K.

1987-11-01

As a part of the Hood River Conservation Project (HRCP), 314 homes were monitored to measure electrical energy use. The total electrical load, space heating load, water heating load (in about 200 homes), wood-stove heat output (in about 100 homes), and indoor temperature were monitored. Data were collected for one full year before and one full year after these homes were retrofit with conservation measures. Local weather information was also collected on a 15-min basis. This data base was used to evaluate the load savings attributable to HRCP. Two methods of weather normalization were used and showed close agreement. The weather-normalized diversified residential load savings on the Pacific Power and Light system and Hood River area peak days were >0.5 kW/household. The average spring, summer, and fall savings were much smaller, <0.1 kW/household. The load factor for the diversified residential load decreased following the conservation retrofit actions. 11 refs., 40 figs., 13 tabs.

Origins of albino and hooded rats: implications from molecular genetic analysis across modern laboratory rat strains.

Directory of Open Access Journals (Sweden)

Takashi Kuramoto

Full Text Available Albino and hooded (or piebald rats are one of the most frequently used laboratory animals for the past 150 years. Despite this fact, the origin of the albino mutation as well as the genetic basis of the hooded phenotype remained unclear. Recently, the albino mutation has been identified as the Arg299His missense mutation in the Tyrosinase gene and the hooded (H locus has been mapped to the ∼460-kb region in which only the Kit gene exists. Here, we surveyed 172 laboratory rat strains for the albino mutation and the hooded (h mutation that we identified by positional cloning approach to investigate possible genetic roots and relationships of albino and hooded rats. All of 117 existing laboratory albino rats shared the same albino missense mutation, indicating they had only one single ancestor. Genetic fine mapping followed by de novo sequencing of BAC inserts covering the H locus revealed that an endogenous retrovirus (ERV element was inserted into the first intron of the Kit gene where the hooded allele maps. A solitary long terminal repeat (LTR was found at the same position to the ERV insertion in another allele of the H locus, which causes the so called Irish (h(i phenotype. The ERV and the solitary LTR insertions were completely associated with the hooded and Irish coat patterns, respectively, across all colored rat strains examined. Interestingly, all 117 albino rat strains shared the ERV insertion without any exception, which strongly suggests that the albino mutation had originally occurred in hooded rats.

Ecological Baseline, Fort Hood, Texas

Science.gov (United States)

1980-08-01

cedar eTm (Uiimus crassifolia), Texas ash (Fraxinus texansis), and Texas persimmon ( Diospyros texana). Conversely, the two predominant tree species...Ilex decidua), Mex- ican buckeye (Ungnadia spjeciosa), and Texas persimmon ( Diospyros texana). Vines included greenbrier (Smilax bona-nox) and white...Hedgehey Cactus (Echinocereus sp.) has been observed on Fort Hood. Due to the brief period of flowering for this genus , the individual species were not

Experimental study on centerline velocities of a rectangular capture hood under realistic conditions.

Science.gov (United States)

He, Xinjian; Lewis, Braxton V; Guffey, Steven E

2018-02-01

Capture hoods are an important component of a local ventilation system designed to reduce exposures to airborne contaminants. The velocity at any point along the centerline of the hood (V x ) is currently estimated using one of many predictive equations developed since the 1930s. It is unproven that those predictive equations for V x are accurate, despite the prodigious number of studies concerning them. Among other issues, almost all experimental verifications were conducted for conditions that were either unrealistically ideal without competing air currents (e.g., zero cross draft) or were not described. This study measured values of V x along the midline using Particle Image Velocimetry (PIV) at distances of 1-14 inches in front of a rectangular capture hood. The experiments were conducted in a large wind tunnel (9' × 12' × 40', H × W × L) using a heated, breathing, anthropomorphically sized manikin. Three 0 degree draft velocities (V draft = 4, 14, and 50 ft/min) were tested, all directed toward the hood face and the back of the manikin (if present). For each value of V draft , the velocity fields were measured in a factorial design with and without the manikin, and with and without a worktable underneath the hood. An ideal condition was represented by a freestanding hood at the 4 fpm draft. Nonideal conditions included the presence of a worktable or manikin, and the combination of table and manikin. Each condition was tested at the three levels of V draft . The experimental results found significant effects (p < 0.001) for V draft , the presence of the manikin, the presence of the worktable, and all combinations of those factors. The effects of the independent variables were most pronounced at distances greater than 10 in (25.4 cm) from the hood face. It is concluded that none of the previously published models accurately predicted V x under the realistic conditions tested in this study. A satisfactory model will have to include terms for V draft and the

Science identity possibilities: a look into Blackness, masculinities, and economic power relations

Science.gov (United States)

Rosa, Katemari

2018-02-01

This forum paper dialogues with Sheron Mark's A bit of both science and economics: a non-traditional STEM identity narrative. In her paper, she discusses the development of a Science, Technology, Engineering, and Mathematics (STEM) identity by a young African American male during an informal STEM for Social Justice Program. Here, the discussion focuses on Black masculinities, identity formation, and the role of science educators in making STEM fields a welcoming place for young Black men. Drawing from Mark's data and discussion, this paper is a dialogue between science identity possibilities in the United States and in Brazil when we look at the intersections of race, gender, and socioeconomic status. Using the shared colonial past of both countries a connection is established to address race relations within science education. The main argument in this paper is that racism can no longer be denied and dismissed by the science education community worldwide and that intersectional approaches are needed to face this issue.

NASA's Chandra Finds Black Holes Are "Green"

Science.gov (United States)

2006-04-01

Black holes are the most fuel efficient engines in the Universe, according to a new study using NASA's Chandra X-ray Observatory. By making the first direct estimate of how efficient or "green" black holes are, this work gives insight into how black holes generate energy and affect their environment. The new Chandra finding shows that most of the energy released by matter falling toward a supermassive black hole is in the form of high-energy jets traveling at near the speed of light away from the black hole. This is an important step in understanding how such jets can be launched from magnetized disks of gas near the event horizon of a black hole. Illustration of Fuel for a Black Hole Engine Illustration of Fuel for a Black Hole Engine "Just as with cars, it's critical to know the fuel efficiency of black holes," said lead author Steve Allen of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University, and the Stanford Linear Accelerator Center. "Without this information, we cannot figure out what is going on under the hood, so to speak, or what the engine can do." Allen and his team used Chandra to study nine supermassive black holes at the centers of elliptical galaxies. These black holes are relatively old and generate much less radiation than quasars, rapidly growing supermassive black holes seen in the early Universe. The surprise came when the Chandra results showed that these "quiet" black holes are all producing much more energy in jets of high-energy particles than in visible light or X-rays. These jets create huge bubbles, or cavities, in the hot gas in the galaxies. Animation of Black Hole in Elliptical Galaxy Animation of Black Hole in Elliptical Galaxy The efficiency of the black hole energy-production was calculated in two steps: first Chandra images of the inner regions of the galaxies were used to estimate how much fuel is available for the black hole; then Chandra images were used to estimate the power required to produce

The Influence of the Bed with a Semiopen Hood on Bacteria Removal in a Negative-Pressure Isolation Room

OpenAIRE

Jeng-Min Huang; Hsiang-Tai Cheng

2014-01-01

This study numerically investigates the influence of a sickbed with a semiopened hood on bacteria removal in a negative-pressure isolation room. The parameters include air change rate, lying style, the length and height of hood, flow rate allotments, and the positions of outlets. The results show that the hood has excellent effect on the removal of contaminated air, which is much better than the case without hood. The flow field of patient's face up cough is very different from face side coug...

A floating bridge disrupts seaward migration and increases mortality of steelhead smolts in Hood Canal, Washington state.

Directory of Open Access Journals (Sweden)

Megan Moore

Full Text Available Habitat modifications resulting from human transportation and power-generation infrastructure (e.g., roads, dams, bridges can impede movement and alter natural migration patterns of aquatic animal populations, which may negatively affect survival and population viability. Full or partial barriers are especially problematic for migratory species whose life histories hinge on habitat connectivity.The Hood Canal Bridge, a floating structure spanning the northern outlet of Hood Canal in Puget Sound, Washington, extends 3.6 meters underwater and forms a partial barrier for steelhead migrating from Hood Canal to the Pacific Ocean. We used acoustic telemetry to monitor migration behavior and mortality of steelhead smolts passing four receiver arrays and several single receivers within the Hood Canal, Puget Sound, and Strait of Juan de Fuca. Twenty-seven mortality events were detected within the vicinity of the Hood Canal Bridge, while only one mortality was recorded on the other 325 receivers deployed throughout the study area. Migrating steelhead smolts were detected at the Hood Canal Bridge array with greater frequency, on more receivers, and for longer durations than smolts migrating past three comparably configured arrays. Longer migration times and paths are likely to result in a higher density of smolts near the bridge in relation to other sites along the migration route, possibly inducing an aggregative predator response to steelhead smolts.This study provides strong evidence of substantial migration interference and increased mortality risk associated with the Hood Canal Bridge, and may partially explain low early marine survival rates observed in Hood Canal steelhead populations. Understanding where habitat modifications indirectly increase predation pressures on threatened populations helps inform potential approaches to mitigation.

A floating bridge disrupts seaward migration and increases mortality of steelhead smolts in Hood Canal, Washington state.

Science.gov (United States)

Moore, Megan; Berejikian, Barry A; Tezak, Eugene P

2013-01-01

Habitat modifications resulting from human transportation and power-generation infrastructure (e.g., roads, dams, bridges) can impede movement and alter natural migration patterns of aquatic animal populations, which may negatively affect survival and population viability. Full or partial barriers are especially problematic for migratory species whose life histories hinge on habitat connectivity. The Hood Canal Bridge, a floating structure spanning the northern outlet of Hood Canal in Puget Sound, Washington, extends 3.6 meters underwater and forms a partial barrier for steelhead migrating from Hood Canal to the Pacific Ocean. We used acoustic telemetry to monitor migration behavior and mortality of steelhead smolts passing four receiver arrays and several single receivers within the Hood Canal, Puget Sound, and Strait of Juan de Fuca. Twenty-seven mortality events were detected within the vicinity of the Hood Canal Bridge, while only one mortality was recorded on the other 325 receivers deployed throughout the study area. Migrating steelhead smolts were detected at the Hood Canal Bridge array with greater frequency, on more receivers, and for longer durations than smolts migrating past three comparably configured arrays. Longer migration times and paths are likely to result in a higher density of smolts near the bridge in relation to other sites along the migration route, possibly inducing an aggregative predator response to steelhead smolts. This study provides strong evidence of substantial migration interference and increased mortality risk associated with the Hood Canal Bridge, and may partially explain low early marine survival rates observed in Hood Canal steelhead populations. Understanding where habitat modifications indirectly increase predation pressures on threatened populations helps inform potential approaches to mitigation.

Orthogonal design on range hood with air curtain and its effects on kitchen environment.

Science.gov (United States)

Liu, Xiaomin; Wang, Xing; Xi, Guang

2014-01-01

Conventional range hoods cannot effectively prevent the oil fumes containing cooking-induced harmful material from escaping into the kitchen Air curtains and guide plates have been used in range hoods to reduce the escape of airborne emissions and heat, thereby improving the kitchen environment and the cook's degree of comfort. In this article, numerical simulations are used to study the effects of the jet velocity of an air curtain, the jet angle of the air curtain, the width of the jet slot, the area of the guide plate, and the exhaust rate of the range hood on the perceived temperature, the perceived concentration of oil fumes, the release temperature of oil fumes, and the concentration of escaped oil fumes in a kitchen. The orthogonal experiment results show that the exhaust rate of the range hood is the main factor influencing the fumes concentration and the temperature distribution in the kitchen. For the range hood examined in the present study, the optimum values of the exhaust rate, the jet velocity of the air curtain, the jet angle of the air curtain, the width of the jet slot, and the area of the guide plate are 10.5 m(3)/min, 1.5 m/s, -5°, 4 mm, and 0.22 m(2), respectively, based on the results of the parametric study. In addition, the velocity field, temperature field, and oil fumes concentration field in the kitchen using the proposed range hood with the air curtain and guide plate are analyzed for those parameters. The study's results provide significant information needed for improving the kitchen environment.

REDESIGN OF OUTER HOOD PANEL OF ESEMKA R2 CAR TO IMPROVE PEDESTRIAN PROTECTION USING FINITE ELEMENT MODELING

Directory of Open Access Journals (Sweden)

Binyamin Binyamin

2016-12-01

Full Text Available Traffic accidents are terrible scourge that occur in many countries, specially for developing countries where transportation affairs like tangled yarn. Besides functioning as an engine compartment cover, the hood of modern compact SUV can also help to manage the impact energy of a pedestrian’s head in a vehicle-pedestrian impact. This paper presents outer hood design of Esemka R2 that has a potential to improve hood’s ability and also to absorb the impact energy of a pedestrian’s head. The developed method for the design of an outer hood configuration aims to provide a robust design and homogeneous of Head Injury Criterion (HIC for impact position at WAD 1000 and three different thicknesses (1.25 mm, 1.35 mm & 1.50 mm of outer hood panel of Esemka R2 compact SUV, taking into consideration the limited space available for deformation. The non-linear Finite Element Analysis (FEA software (Explicit Dynamics was used in this research to simulate the testing procedurs of head impact for child pedestrian. The results show that the average of comparison dimensional of outer hood panel of Esemka R2 was 4.89 mm. The minimum of deformation space meet the requirement for HIC value which required obtaining robust and homogeneous head impact performance. Outer hood thickness and materials were identified as the factors to influence the stress and HIC value of the hood. By comparing all outer hood panels, aluminium alloy as the best selected material which has the lowest value is 32.78% for the pedestrian protection.

General experiences + race + racism = Work lives of Black faculty in postsecondary science education

Science.gov (United States)

Parsons, Eileen R. C.; Bulls, Domonique L.; Freeman, Tonjua B.; Butler, Malcolm B.; Atwater, Mary M.

2016-12-01

Existent research indicates that postsecondary Black faculty members, who are sorely underrepresented in the academy especially in STEM fields, assume essential roles; chief among these roles is diversifying higher education. Their recruitment and retention become more challenging in light of research findings on work life for postsecondary faculty. Research has shown that postsecondary faculty members in general have become increasingly stressed and job satisfaction has declined with dissatisfaction with endeavors and work overload cited as major stressors. In addition to the stresses managed by higher education faculty at large, Black faculty must navigate diversity-related challenges. Illuminating and understanding their experiences can be instrumental in lessening stress and job dissatisfaction, outcomes that facilitate recruitment and retention. This study featured the experiences and perceptions of Black faculty in science education. This study, framed by critical race theory, examines two questions: What characterizes the work life of some Black faculty members who teach, research, and serve in science education? How are race and racism present in the experiences of these postsecondary Black faculty members? A phenomenological approach to the study situates the experiences of the Black participants as valid phenomena worthy of investigation, illuminates their experiences, and seeks to retain the authenticity of their voices.

Sexual aggression by intruders in hooded crow Corvus cornix.

Science.gov (United States)

Zduniak, Piotr; Kosicki, Jakub Z; Yosef, Reuven

The hooded crow Corvus cornix is a west Palaearctic, solitary nesting, monogamous corvid. In the breeding season, populations are characterized by a social organization wherein breeding pairs are territorial and non-breeding individuals, called floaters, live in flocks. During a study of the breeding ecology of the hooded crow, conducted in a protected flooded area, we monitored nests with video cameras. We recorded two separate incidents when intruders attacked a female at the nest. We believe that she remained in the nest in order to prevent the strangers cannibalizing the nestlings by mantling over the brood. The spatio-temporal occurrence of these attacks suggests that the observed behaviour is intraspecific sexual aggression wherein non-breeding males mounted an immobilized female.

Humboldt Open Ocean Disposal Site (HOODS) Survey Work 2014

Data.gov (United States)

U.S. Environmental Protection Agency — The Humboldt Open Ocean Disposal Site (HOODS) is a dredged material disposal site located 3 nautical miles (nm) offshore of Humboldt Bay in Northern California....

Persistence of Change: Fume Hood Campaign Lessons

Science.gov (United States)

Feder, Elah; Robinson, Jennifer; Wakefield, Sarah

2012-01-01

Purpose: Sustainability initiatives typically operate for a limited time period, but it is often unclear whether they have lasting effects. The purpose of this paper is to examine a laboratory fume hood campaign, in order to identify factors that might contribute or detract from long-term change persistence. Design/methodology/approach: The…

The Structural Relationship between Out-of-School Time Enrichment and Black Student Participation in Advanced Science

Science.gov (United States)

Young, Jamaal; Young, Jemimah

2018-01-01

The researchers tested a model of the structural relationship between Black student engagement in out-of-school time (OST) science enrichment and participation in advanced science courses in high school. The participants in the sample were Black students (N = 3,173) who participated in the High School Longitudinal Study of 2009/2012. The student…

Reduced-scale experimental investigation on ventilation performance of a local exhaust hood in an industrial plant

DEFF Research Database (Denmark)

Huang, Yanqiu; Wang, Yi; Liu, Li

2015-01-01

stratification in the working areas of industrial plants. Investigated factors were confined airflow boundaries, flow rates of the exhaust hoods, source strengths, airflow obstacles and distances between sources and exhaust hoods. Reduced-scale experiments were conducted with a geometric scale of 1...... efficiency. Hood performance was also evaluated by thermal stratification heights in the plants. This study could help improve the capture efficiency of local ventilation systems used in industrial plants. Safe operation heights are recommended in the upper space of industrial plants based on the thermal...

42 CFR 84.135 - Half-mask facepieces, full facepieces, hoods, and helmets; fit; minimum requirements.

Science.gov (United States)

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Half-mask facepieces, full facepieces, hoods, and... OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.135 Half-mask facepieces, full facepieces, hoods, and helmets; fit; minimum requirements. (a) Half-mask facepieces and full facepieces shall...

Hood River and Pelton Ladder Evaluation Studies, 2008 Annual Report : October 2007 - September 2008.

Energy Technology Data Exchange (ETDEWEB)

Reagan, Robert E.; Olsen, Erik A. [Oregon Department of Fish and Wildlife

2009-09-28

This report summarizes the life history and production data collected in the Hood River subbasin during FY 2008. Included is a summary of jack and adult life history data collected at the Powerdale Dam trap on seventeen complete run years of winter steelhead, spring and fall chinook salmon, and coho salmon, and on fifteen complete run years of summer steelhead. Also included are summaries of (1) the hatchery winter steelhead broodstock collection program; (2) hatchery production releases in the Hood River subbasin; (3) subbasin wild summer and winter steelhead smolt production, (4) numbers of hatchery summer and winter steelhead smolts leaving the subbasin; (5) smolt migration timing past Bonneville Dam, (6) wild and hatchery steelhead smolt-to-adult survival rates; (7) wild summer and winter steelhead egg to smolt survival rates; and (8) streamflow at selected locations in the Hood River subbasin. Data will be used in part to (1) evaluate the HRPP relative to its impact on indigenous populations of resident and anadromous salmonids (see Ardren Draft), (2) evaluate the HRPP's progress towards achieving the biological fish objectives defined in the Hood River Subbasin Plan (Coccoli 2004) and the Revised Master Plan for the Hood River Production Program (HDR|FishPro, ODFW, and CTWSRO 2008), (3) refine spawner escapement objectives to more accurately reflect subbasin carrying capacity, and (4) refine estimates of subbasin smolt production capacity to more accurately reflect current and potential subbasin carrying capacity.

Brucella pinnipedialis hooded seal (Cystophora cristata) strain in the mouse model with concurrent exposure to PCB 153.

Science.gov (United States)

Nymo, Ingebjørg H; das Neves, Carlos G; Tryland, Morten; Bårdsen, Bård-Jørgen; Santos, Renato Lima; Turchetti, Andreia Pereira; Janczak, Andrew M; Djønne, Berit; Lie, Elisabeth; Berg, Vidar; Godfroid, Jacques

2014-05-01

Brucellosis, a worldwide zoonosis, is linked to reproductive problems in primary hosts. A high proportion of Brucella-positive hooded seals (Cystophora cristata) have been detected in the declined Northeast Atlantic stock. High concentrations of polychlorinated biphenyls (PCBs) have also been discovered in top predators in the Arctic, including the hooded seal, PCB 153 being most abundant. The aim of this study was to assess the pathogenicity of Brucella pinnipedialis hooded seal strain in the mouse model and to evaluate the outcome of Brucella spp. infection after exposure of mice to PCB 153. BALB/c mice were infected with B. pinnipedialis hooded seal strain or Brucella suis 1330, and half from each group was exposed to PCB 153 through the diet. B. pinnipedialis showed a reduced pathogenicity in the mouse model as compared to B. suis 1330. Exposure to PCB 153 affected neither the immunological parameters, nor the outcome of the infection. Altogether this indicates that it is unlikely that B. pinnipedialis contribute to the decline of hooded seals in the Northeast Atlantic. Copyright © 2014 Elsevier Ltd. All rights reserved.

Energy Impacts of Effective Range Hood Use for all U.S. Residential Cooking

Energy Technology Data Exchange (ETDEWEB)

Logue, Jennifer M; Singer, Brett

2014-06-01

Range hood use during residential cooking is essential to maintaining good indoor air quality. However, widespread use will impact the energy demand of the U.S. housing stock. This paper describes a modeling study to determine site energy, source energy, and consumer costs for comprehensive range hood use. To estimate the energy impacts for all 113 million homes in the U.S., we extrapolated from the simulation of a representative weighted sample of 50,000 virtual homes developed from the 2009 Residential Energy Consumption Survey database. A physics-based simulation model that considered fan energy, energy to condition additional incoming air, and the effect on home heating and cooling due to exhausting the heat from cooking was applied to each home. Hoods performing at a level common to hoods currently in U.S. homes would require 19?33 TWh [69?120 PJ] of site energy, 31?53 TWh [110-190 PJ] of source energy; and would cost consumers $1.2?2.1 billion (U.S.$2010) annually in the U.S. housing stock. The average household would spend less than $15 annually. Reducing required airflow, e.g. with designs that promote better pollutant capture has more energy saving potential, on average, than improving fan efficiency.

A new method for infrared imaging of air currents in and around critical hazard fume hoods

International Nuclear Information System (INIS)

Mulac, W.A.; McCreary, J.R.; Schmalz, H.

1992-01-01

A real time method of measuring and recording the efficacy of vapor containment in and around critical hazard fume hoods is being developed. An infrared camera whose response is restricted to a spectral range that overlaps a strong absorption band in a non-toxic gas is used to render real-time video images of the presence and flow of the gas. The gas, nitrous oxide, is ejected in a continuous stream in and around fume hoods that are to be certified capable of containing hazardous fumes. The principle advantage is that various scenarios of air flow displacement in and outside the hood can be easily investigated; the principle limitation is the necessity of high tracer gas concentration to obtain strong visualizations. We hope that this technique can be found to be an effective and safe method to test hoods in locations that were built before present regulations were promulgated

Potential inhalation exposure and containment efficiency when using hoods for handling nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Tsai, Candace Su-Jung, E-mail: tsai51@purdue.edu [Purdue University, School of Health Science (United States)

2013-09-15

Inhalation exposure to airborne nanoparticles (NPs) has been reported during manual activities using typical fume hoods. This research studied potential inhalation exposure associated with the manual handling of NPs using two new nanoparticle-handling enclosures and two biological safety cabinets, and discussed the ability to contain NPs in the hoods to reduce environmental release and exposure. Airborne concentrations of 5 nm to 20 {mu}m diameter particles were measured while handling nanoalumina particles in various ventilated enclosures. Tests were conducted using two handling conditions and concentrations were measured using real-time particle counters, and particles were collected on transmission electron microscope grids to determine particle morphology and elemental composition. Airflow patterns were characterized visually using a laser-light sheet and fog. The average number concentration increase at breathing zone outside the enclosure was less than 1,400 particle/cm{sup 3} for each particle size at all tested conditions and the estimated overall mass concentration was about 83 {mu}g/m{sup 3} which was less than the dosage of typical nanoparticle inhalation exposure studies. The typical front-to-back airflow was used in the studied hoods, which could potentially induce reverse turbulence in the wake region. However, containment of NPs using studied hoods was demonstrated with excellent performance. Smoke tests showed that worker's hand motion could potentially cause nanoparticle escape. The challenge of front-to-back airflow can be partially overcome by gentle motion, low face velocity, and front exhaust to reduce nanoparticle escape.

42 CFR 84.1135 - Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements.

Science.gov (United States)

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Half-mask facepieces, full facepieces, hoods... Air-Purifying High Efficiency Respirators and Combination Gas Masks § 84.1135 Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements. (a) Half-mask facepieces...

Entrance and Survival of Brucella pinnipedialis Hooded Seal Strain in Human Macrophages and Epithelial Cells

Science.gov (United States)

Briquemont, Benjamin; Sørensen, Karen K.; Godfroid, Jacques

2013-01-01

Marine mammal Brucella spp. have been isolated from pinnipeds (B. pinnipedialis) and cetaceans (B. ceti) from around the world. Although the zoonotic potential of marine mammal brucellae is largely unknown, reports of human disease exist. There are few studies of the mechanisms of bacterial intracellular invasion and multiplication involving the marine mammal Brucella spp. We examined the infective capacity of two genetically different B. pinnipedialis strains (reference strain; NTCT 12890 and a hooded seal isolate; B17) by measuring the ability of the bacteria to enter and replicate in cultured phagocytes and epithelial cells. Human macrophage-like cells (THP-1), two murine macrophage cell lines (RAW264.7 and J774A.1), and a human malignant epithelial cell line (HeLa S3) were challenged with bacteria in a gentamicin protection assay. Our results show that B. pinnipedialis is internalized, but is then gradually eliminated during the next 72 – 96 hours. Confocal microscopy revealed that intracellular B. pinnipedialis hooded seal strain colocalized with lysosomal compartments at 1.5 and 24 hours after infection. Intracellular presence of B. pinnipedialis hooded seal strain was verified by transmission electron microscopy. By using a cholesterol-scavenging lipid inhibitor, entrance of B. pinnipedialis hooded seal strain in human macrophages was significantly reduced by 65.8 % (± 17.3), suggesting involvement of lipid-rafts in intracellular entry. Murine macrophages invaded by B. pinnipedialis do not release nitric oxide (NO) and intracellular bacterial presence does not induce cell death. In summary, B. pinnipedialis hooded seal strain can enter human and murine macrophages, as well as human epithelial cells. Intracellular entry of B. pinnipedialis hooded seal strain involves, but seems not to be limited to, lipid-rafts in human macrophages. Brucella pinnipedialis does not multiply or survive for prolonged periods intracellulary. PMID:24376851

Reaching for 100% participation in a utility conservation programme: the Hood River project

Energy Technology Data Exchange (ETDEWEB)

Hirst, Eric

1989-04-01

The Hood River Conservation Project (HRCP) was a major residential retrofit demonstration project. The project was intended to install as many cost-effective retrofit measures in all electrically heated homes in Hood River, OR, USA. To achieve 100% participation, HRCP offered a package of 'super' retrofit measures and paid for installation of these measures. Almost all (91%) of the eligible households participated, in stark contrast to the much lower participation levels achieved in other residential conservation programmes. Also, unlike other programmes, HRCP attracted larger fractions of traditionally hard-to-reach groups: low-income households; occupants of multifamily units; and renters. The key factors leading to this phenomenal success include: the offer of free retrofits; determination on the part of staff to enlist every eligible household; the use of community-based marketing approaches; and reliance on extensive word-of-mouth among Hood River residents. (author).

42 CFR 84.175 - Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements.

Science.gov (United States)

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Half-mask facepieces, full facepieces, hoods....175 Half-mask facepieces, full facepieces, hoods, helmets, and mouthpieces; fit; minimum requirements. (a) Half-mask facepieces and full facepieces shall be designed and constructed to fit persons with...

Locating inputs of freshwater to Lynch Cove, Hood Canal, Washington, using aerial infrared photography

Science.gov (United States)

Sheibley, Rich W.; Josberger, Edward G.; Chickadel, Chris

2010-01-01

The input of freshwater and associated nutrients into Lynch Cove and lower Hood Canal (fig. 1) from sources such as groundwater seeps, small streams, and ephemeral creeks may play a major role in the nutrient loading and hydrodynamics of this low dissolved-oxygen (hypoxic) system. These disbursed sources exhibit a high degree of spatial variability. However, few in-situ measurements of groundwater seepage rates and nutrient concentrations are available and thus may not represent adequately the large spatial variability of groundwater discharge in the area. As a result, our understanding of these processes and their effect on hypoxic conditions in Hood Canal is limited. To determine the spatial variability and relative intensity of these sources, the U.S. Geological Survey Washington Water Science Center collaborated with the University of Washington Applied Physics Laboratory to obtain thermal infrared (TIR) images of the nearshore and intertidal regions of Lynch Cove at or near low tide. In the summer, cool freshwater discharges from seeps and streams, flows across the exposed, sun-warmed beach, and out on the warm surface of the marine water. These temperature differences are readily apparent in aerial thermal infrared imagery that we acquired during the summers of 2008 and 2009. When combined with co-incident video camera images, these temperature differences allow identification of the location, the type, and the relative intensity of the sources.

Opening the Big Black Box: European study reveals visitors' impressions of science laboratories

CERN Multimedia

2004-01-01

"On 29 - 30 March the findings of 'Inside the Big Black Box'- a Europe-wide science and society project - will be revealed during a two-day seminar hosted by CERN*. The principle aim of Inside the Big Black Box (IN3B) is to determine whether a working scientific laboratory can capture the curiosity of the general public through visits" (1 page)

Don Quixote, Machiavelli, and Robin Hood: public health practice, past and present.

Science.gov (United States)

Mullan, F

2000-05-01

Since the mid-19th century, when the first formal health departments were established in the United States, commissioners, directors, and secretaries of public health have functioned as senior members of the staffs of public executives, mayors, governors, and presidents. They have provided important political, managerial, and scientific leadership to agencies of government that have played increasingly important roles in national life, from the sanitary revolution of the 19th century to the prevention of HIV/AIDS and the control of tobacco use today. Although public health officials come from a variety of backgrounds and oversee agencies of varied size and composition, there are philosophical themes that describe and define the commonality of their work. These themes are captured metaphorically by 3 celebrated figures: Don Quixote, Machiavelli, and Robin Hood. By turns, the public health official functions as a determined idealist (Don Quixote), a cunning political strategist (Machiavelli), and an agent who redistributes resources from the wealthier sectors of society to the less well off (Robin Hood.) All 3 personae are important, but, it is argued, Robin Hood is the most endangered.

Contrast fluoroscopic evaluation of gastrointestinal transit times with and without the use of falconry hoods in red-tailed hawks (Buteo jamaicensis).

Science.gov (United States)

Doss, Grayson A; Williams, Jackie M; Mans, Christoph

2017-11-01

OBJECTIVE To evaluate gastrointestinal transit times in red-tailed hawks (Buteo jamaicensis) by use of contrast fluoroscopic imaging and investigate the effect of falconry hooding in these hawks on gastrointestinal transit time. DESIGN Prospective, randomized, blinded, complete crossover study. ANIMALS 9 healthy red-tailed hawks. PROCEDURES Hawks were gavage-fed a 30% weight-by-volume barium suspension (25 mL/kg [11.3 mL/lb]) into the crop. Fluoroscopic images were obtained at multiple time points after barium administration. Time to filling and emptying of various gastrointestinal tract organs and overall transit time were measured. The effect of hooding (hooded vs nonhooded) on these variables was assessed in a randomized complete crossover design. RESULTS In nonhooded birds, overall gastrointestinal transit time ranged from 30 to 180 minutes (mean ± SD, 100 ± 52 min). Time to complete crop emptying ranged from 30 to 180 minutes (83 ± 49 min). Contrast medium was present in the ventriculus in all birds within 5 minutes of administration and in the small intestines within 5 to 15 minutes (median, 5 min). Hooding of red-tailed hawks resulted in a significant delay of complete crop emptying (no hood, 83 ± 49 minutes; hood, 133 ± 48 minutes), but no significant effects of hooding were found on other measured variables. CONCLUSIONS AND CLINICAL RELEVANCE These results indicated that overall gastrointestinal transit times are faster in red-tailed hawks than has been reported for psittacines and that the use of a falconry hood in red-tailed hawks may result in delayed crop emptying. Hooding did not exert significant effects on overall gastrointestinal transit time in this raptorial species.

A support approach for the conceptual design of energy-efficient cooker hoods

International Nuclear Information System (INIS)

Cicconi, Paolo; Landi, Daniele; Germani, Michele; Russo, Anna Costanza

2017-01-01

Highlights: •An eco-innovation approach to support the design of household appliances. •The research is focused on the energy labelling for kitchen hoods. •A software platform provides tools to configure and optimize new solutions. •A tool can calculate the energy efficiency indexes of a product configuration. -- Abstract: In Europe, kitchen hoods currently come with an energy label showing their energy efficiency class and other information regarding the energy consumption and noise level, as established by the European Energy Labelling Directive. Because of recent regulations, designs of cooker hoods must consider new issues, such as the evaluation of the energy efficiency, analysis of the energy consumption, and product lifecycle impact. Therefore, the development of eco-driven products requires Ecodesign tools to support eco-innovation and related sustainability improvements. The scope of the proposed research is to define a method and an agile and affordable platform tool that can support designers in the early estimation of product energy performance, including the calculation of energy efficiency indexes. The approach also considers the use of genetic algorithm methods to optimize the product configuration in terms of energy efficiency. The research context concerns large and small productions of kitchen hoods. The paper describes the methodological approach within the developed tool. The results show a good correlation between real efficiency values and calculated ones. A validation activity has been described, and a test case shows how to apply the proposed approach for the design of a new efficient product with an A-class Energy Efficiency Index.

Freshwater and Saline Loads of Dissolved Inorganic Nitrogen to Hood Canal and Lynch Cove, Western Washington

Science.gov (United States)

Paulson, Anthony J.; Konrad, Christopher P.; Frans, Lonna M.; Noble, Marlene; Kendall, Carol; Josberger, Edward G.; Huffman, Raegan L.; Olsen, Theresa D.

2006-01-01

Hood Canal is a long (110 kilometers), deep (175 meters) and narrow (2 to 4 kilometers wide) fjord of Puget Sound in western Washington. The stratification of a less dense, fresh upper layer of the water column causes the cold, saltier lower layer of the water column to be isolated from the atmosphere in the late summer and autumn, which limits reaeration of the lower layer. In the upper layer of Hood Canal, the production of organic matter that settles and consumes dissolved oxygen in the lower layer appears to be limited by the load of dissolved inorganic nitrogen (DIN): nitrate, nitrite, and ammonia. Freshwater and saline loads of DIN to Hood Canal were estimated from available historical data. The freshwater load of DIN to the upper layer of Hood Canal, which could be taken up by phytoplankton, came mostly from surface and ground water from subbasins, which accounts for 92 percent of total load of DIN to the upper layer of Hood Canal. Although DIN in rain falling on land surfaces amounts to about one-half of the DIN entering Hood Canal from subbasins, rain falling directly on the surface of marine waters contributed only 4 percent of the load to the upper layer. Point-source discharges and subsurface flow from shallow shoreline septic systems contributed less than 4 percent of the DIN load to the upper layer. DIN in saline water flowing over the sill into Hood Canal from Admiralty Inlet was at least 17 times the total load to the upper layer of Hood Canal. In September and October 2004, field data were collected to estimate DIN loads to Lynch Cove - the most inland marine waters of Hood Canal that routinely contain low dissolved-oxygen waters. Based on measured streamflow and DIN concentrations, surface discharge was estimated to have contributed about one-fourth of DIN loads to the upper layer of Lynch Cove. Ground-water flow from subbasins was estimated to have contributed about one-half of total DIN loads to the upper layer. In autumn 2004, the relative

Sodium-glucose cotransporter 2 inhibition and health benefits: The Robin Hood effect.

Science.gov (United States)

Kalra, Sanjay; Jain, Arpit; Ved, Jignesh; Unnikrishnan, A G

2016-01-01

This review discusses two distinct, yet related, mechanisms of sodium-glucose cotransporter 2 (SGLT2) inhibition: Calorie restriction mimicry (CRM) and pro-ketogenic effect, which may explain their cardiovascular benefits. We term these adaptive CRM and pro-ketogenic effects of SGLT2 inhibition, the Robin Hood hypothesis. In English history, Robin Hood was a "good person," who stole from the rich and helped the poor. He supported redistribution of resources as he deemed fit for the common good. In a similar fashion, SGLT2 inhibition provides respite to the overloaded glucose metabolism while utilizing lipid stores for energy production.

Sodium-glucose cotransporter 2 inhibition and health benefits: The Robin Hood effect

Directory of Open Access Journals (Sweden)

Sanjay Kalra

2016-01-01

Full Text Available This review discusses two distinct, yet related, mechanisms of sodium-glucose cotransporter 2 (SGLT2 inhibition: Calorie restriction mimicry (CRM and pro-ketogenic effect, which may explain their cardiovascular benefits. We term these adaptive CRM and pro-ketogenic effects of SGLT2 inhibition, the Robin Hood hypothesis. In English history, Robin Hood was a "good person," who stole from the rich and helped the poor. He supported redistribution of resources as he deemed fit for the common good. In a similar fashion, SGLT2 inhibition provides respite to the overloaded glucose metabolism while utilizing lipid stores for energy production.

The decline of an urban Hooded Vulture Necrosyrtes monachus ...

African Journals Online (AJOL)

Likely causes are (1) exponential urbanisation resulting in loss of feeding sites and reduced food availability, (2) increased poisoning of feral dogs with strychnine sulphate due to an upsurge of rabies and (3) increased disappearance of suitable trees for nesting and roosting. Keywords: cutting of trees, Hooded Vulture, ...

Dynamics of participation and supply of services in the Hood River Conservation Project

Energy Technology Data Exchange (ETDEWEB)

Hirst, E.; Goeltz, R.

1986-07-01

The Hood River Conservation Project (HRCP) is a major residential retrofit demonstration project. HRCP is funded by the Bonneville Power Administration (BPA) and run by Pacific Power and Light Company. The project was conducted in the community of Hood River, Oregon, will cost $21 million, and will last for three years (mid-1983 through 1986). Installation of applicable retrofit measures was completed by the end of 1985; data collection, analysis, and report writing will continue through 1986. This report documents the extent to which households participated in HRCP. Differences between participants and eligible nonparticipants are examined. Similarly, differences among participants as a function of when they signed up for HRCP are analyzed. The report also examines the dynamics of program services (i.e., times between audit requests and audit, and between audit and installation of measures). These analyses are based on data from the roughly 3500 Hood River homes eligible for HRCP, 3189 of which received free home energy audits and 2988 of which received HRCP-financed retrofit measures.

The trials, tribulations, and triumphs of black faculty in the math and science pipeline: A life history approach

Science.gov (United States)

Williams, Lisa D.

2000-12-01

This study explores the career progression and life history of black mathematicians and scientists who teach on university faculties in the United States. It investigates the following questions: Why are there so few black mathematicians and scientists in colleges and universities in the United States? What is the experience of black students who express an interest in science and math? What barriers do black scientists and mathematicians face as they move through school towards their career in higher education? What factors facilitate their success? The current literature shows that there are few women and minorities teaching or working in math and science compared to white men, although reasons for this underrepresentation are still not well understood. I explored this phenomenon by conducting two sets of in-depth interviews with twelve black faculty, six women, six men, from both historically black and predominantly white higher educational institutions in the United States. My interviews were based upon a life history approach that identified the participants' perceptions of the barriers and obstacles, as well as the supports and facilitators encountered in their schooling and career progression. The findings from the study show the importance of a strong family, community, and teacher support for the participants throughout their schooling. Support systems continued to be important in their faculty positions. These support systems include extended family members, teachers, community members, supervisors, and classmates, who serve as role models and mentors. The life study interviews provide striking evidence of the discrimination, isolation, and harassment due to race and gender experienced by black male and female mathematicians and scientists. The racial discrimination and the compounding effect of racism and sexism play out differently for the male and female participants in this study. This study suggests directions for future research on the experiences

77 FR 12514 - Drawbridge Operation Regulation; Hood Canal, WA

Science.gov (United States)

2012-03-01

... operating regulation for the Hood Canal floating drawbridge near Port Gamble. This modification would relieve heavy rush hour road traffic on State Routes 3 and 104, by allowing the draws of the bridge to not.... FOR FURTHER INFORMATION CONTACT: If you have questions on this rule, call or email the Bridge...

Transfer hood for handling fuel assemblies in nuclear reactors and especially fast reactors

International Nuclear Information System (INIS)

Aubert, M.; Merland, D.; Renaux, C.

1975-01-01

A description is given of a hood for transferring fuel assemblies between two or more separate guide ramps inclined to the vertical at the same angle of slope and extending respectively through a first passage into the reactor vessel and through a second passage into a fuel-assembly storage chamber. The hood comprises at least one shielded duct joined to a flanged rotating portion which is so arranged that the open lower end of the shielded duct is positioned in the line of extension of one guide ramp and then the other as a result of displacement of the rotating portion

Hood River Monitoring and Evaluation Project, Annual Report 2002-2003.

Energy Technology Data Exchange (ETDEWEB)

Vaivoda, Alexis

2004-02-01

The Hood River Production Program Monitoring and Evaluation Project is co-managed by the Confederated Tribes of Warm Springs (CTWSRO) and the Oregon Department of Fish and Wildlife. The program is divided up to share responsibilities, provide efficiency, and avoid duplication. From October 2002 to September 2003 (FY 03) project strategies were implemented to monitor, protect, and restore anadromous fish and fish habitat in the Hood River subbasin. A description of the progress during FY 03 is reported here. Additionally an independent review of the entire program was completed in 2003. The purpose of the review was to determine if project goals and actions were achieved, look at critical uncertainties for present and future actions, determine cost effectiveness, and choose remedies that would increase program success. There were some immediate changes to the implementation of the project, but the bulk of the recommendations will be realized in coming years.

Renewable Energy Opportunities at Fort Hood, Texas

Energy Technology Data Exchange (ETDEWEB)

Chvala, William D.; Warwick, William M.; Dixon, Douglas R.; Solana, Amy E.; Weimar, Mark R.; States, Jennifer C.; Reilly, Raymond W.

2008-06-30

The document provides an overview of renewable resource potential at Fort Hood based primarily upon analysis of secondary data sources supplemented with limited on-site evaluations. The effort was funded by the U.S. Army Installation Management Command (IMCOM) as follow-on to the 2005 DoD Renewables Assessment. This effort focuses on grid-connected generation of electricity from renewable energy sources and also ground source heat pumps for heating and cooling buildings, as directed by IMCOM.

An Examination of Black Science Teacher Educators' Experiences with Multicultural Education, Equity, and Social Justice

Science.gov (United States)

Atwater, Mary M.; Butler, Malcolm B.; Freeman, Tonjua B.; Carlton Parsons, Eileen R.

2013-12-01

Diversity, multicultural education, equity, and social justice are dominant themes in cultural studies (Hall in Cultural dialogues in cultural studies. Routledge, New York, pp 261-274, 1996; Wallace 1994). Zeichner (Studying teacher education: The report of the AERA panel on research and teacher education. Lawrence Erlbaum Associates, Mahwah, pp 737-759, 2005) called for research studies of teacher educators because little research exists on teacher educators since the late 1980s. Thomson et al. (2001) identified essential elements needed in order for critical multiculturalism to be infused in teacher education programs. However, little is known about the commitment and experiences of science teacher educators infusing multicultural education, equity, and social justice into science teacher education programs. This paper examines twenty (20) Black science teacher educators' teaching experiences as a result of their Blackness and the inclusion of multicultural education, equity, and social justice in their teaching. This qualitative case study of 20 Black science teacher educators found that some of them have attempted and stopped due to student evaluations and the need to gain promotion and tenure. Other participants were able to integrate diversity, multicultural education, equity and social justice in their courses because their colleagues were supportive. Still others continue to struggle with this infusion without the support of their colleagues, and others have stopped The investigators suggest that if science teacher educators are going to prepare science teachers for the twenty first century, then teacher candidates must be challenged to grapple with racial, ethnic, cultural, instructional, and curricular issues and what that must mean to teach science to US students in rural, urban, and suburban school contexts.

Contamination Status of Seven Elements in Hooded Cranes Wintering in South-West Kyushu, Japan: Comparison with Red-Crowned Cranes in Hokkaido, Japan.

Science.gov (United States)

Teraoka, Hiroki; Miyagi, Hasumi; Haraguchi, Yuko; Takase, Kozo; Kitazawa, Takio; Noda, Jun

2018-05-31

The hooded crane is designated as an endangered species. The cranes breed primarily in wetlands in southeast Russia and China in summer. Most of the hooded crane population winters in the Izumi plain in Japan. It is difficult to know the contamination status of their habitat because of their vast breeding area. We determined the levels of Cd, Pb, As, (total) Hg, Se, Zn, and Cu in the liver, kidney, and muscle of hooded cranes that were found dead in Izumi in the periods 2003-2006 and 2014-2015 compared with the levels in red-crowned cranes in Hokkaido, Japan, as the only cranes in which these elements had been studied extensively. There were no notable differences between levels of the seven elements in the two periods. Overall, tissue levels of the elements examined in hooded cranes were comparable to those in red-crowned cranes except for Hg and Se. Tissue levels of Hg and Se were clearly lower in hooded cranes than in red-crowned cranes that were found dead from 2000. One lead poisoning case was confirmed. The results suggest that Hooded cranes wintering in Izumi are not extensively contaminated with the seven elements examined.

First glimpse of the functional benefits of clitoral hood piercings.

Science.gov (United States)

Millner, Vaughn S; Eichold, Bernard H; Sharpe, Thomasina H; Lynn, Sherwood C

2005-09-01

In this exploratory study, we identify a positive relationship between vertical clitoral hood piercing and desire, frequency of intercourse and arousal. There were no dramatic differences in orgasmic functioning. Clinicians can play key roles in educating patients about potential outcomes and risks of genital piercing.

Digital data for preliminary geologic map of the Mount Hood 30- by 60-minute quadrangle, northern Cascade Range, Oregon

Science.gov (United States)

Lina Ma,; Sherrod, David R.; Scott, William E.

2014-01-01

The Mount Hood 30- by 60-minute quadrangle covers the axis and east flank of the Cascade Range in northern Oregon. Its namesake, Mount Hood volcano, dominates the view in the northwest quarter of the quadrangle, but the entire area is underlain by Oligocene and younger volcanic and volcaniclastic rocks of the Cascade Range. Since the time of the Columbia River Basalt Group about 15 million years (m.y.) ago, the locus and composition of Cascade Range volcanism have shifted sporadically across the map area. Andesitic eruptions were predominant in the western part from about 14 to 10 m.y. ago (Salmon and Sandy Rivers area), producing the Rhododendron Formation and overlying lava flows. From about 8 to 6.5 m.y. ago, lithic pyroclastic debris of the Dalles Formation was shed by chiefly andesitic volcanoes in the north-central part of the map area (Hood River valley escarpment). Andesitic to dacitic volcanism was again predominant about 5 to 3 m.y. ago, with known eruptive centers located from Lookout Mountain westward to Lolo Pass, probably including the area now occupied by Mount Hood. A major episode of mafic volcanism-basalt and basaltic andesite-began about 3-4 m.y. ago and lasted until about 2 m.y. ago. Volcanism since about 2 m.y. ago has been concentrated along the axis of the High Cascades. North and south of Mount Hood these youngest rocks are predominantly basaltic andesite lava flows; whereas at Mount Hood itself, andesite is predominant, forming pyroclastic and debris-flow deposits and lava flows.

Análise de convergência espacial dos repasses da Lei Robin Hood Spatial convergence analysis of tax transfers from the Robin Hood Act

Directory of Open Access Journals (Sweden)

Noé Gonçalves Maranduba Júnior

2009-12-01

Full Text Available Alega-se que a Lei Robin Hood tem permitido uma melhor distribuição dos valores do ICMS devidos aos municípios do estado de Minas Gerais. O objetivo deste artigo é investigar se essa lei, entre os anos de 2001 e 2005, realmente foi eficaz, isto é, se, em termos relativos, municípios pobres receberam mais dessas transferências do que os municípios ricos. Para fazer isso metodologicamente, implementa-se uma análise exploratória de dados espaciais e uma análise de convergência, para verificar se as disparidades nos repasses diminuíram com o passar do tempo. Os resultados mostraram que os efeitos espaciais importaram nas análises e que não houve um efeito redistributivo dos repasses, considerando-se que o coeficiente indicador de convergência não foi significativo.One alleges that the Robin Hood Act has allowed one better distribution of the values of ICMS to municipalities of the state of Minas Gerais. The paper is aimed at verifying if the Robin Hood Act has actually revealed a redistributive effect in tax transfers to municipalities in the state over the period 2001-2005, that is, if, in relative terms, poor municipalities have received more these transfers than rich ones. In doing methodologically so, an exploratory spatial data analysis and a convergence analysis are implemented to verify if the disparities of tax redistribution have diminished over the time. The findings showed that the spatial effects were important in the analysis as well as there was no redistributive effect in the period because the convergence coefficient was not significant.

Mass transfer inside a flux hood for the sampling of gaseous emissions from liquid surfaces - Experimental assessment and emission rate rescaling

Science.gov (United States)

Prata, Ademir A.; Lucernoni, Federico; Santos, Jane M.; Capelli, Laura; Sironi, Selena; Le-Minh, Nhat; Stuetz, Richard M.

2018-04-01

This study assesses the mass transfer of compounds inside the US EPA flux hood, one of the enclosure devices most commonly employed for the direct measurement of atmospheric emissions from liquid surfaces in wastewater treatment plants (WWTPs). Experiments comprised the evaporation of water and the volatilisation of a range of volatile organic compounds (VOCs). Special attention was given to the evaluation of the mass transfer coefficients in the microenvironment created by the flux hood and the effects of concentration build up in the hood's headspace. The VOCs emission rates and the water evaporation rates generally increased with the sweep air flow rate, as did the mass transfer coefficients for all compounds. The emission of compounds whose volatilisation is significantly influenced by the gas phase was greatly affected by concentration build up, whereas this effect was not significant for liquid phase-controlled compounds. The gas-film mass transfer coefficient (kG) estimated inside the US EPA flux hood was of the same order as the respective kG reported in the literature for wind tunnel-type devices, but the emission rates measured by the flux hood can be expected to be lower, due to the concentration build-up. Compared against an emission model for the passive surfaces in WWTPs, the mass transfer of acetic acid (representing a gas phase-dominated compound) inside the US EPA flux hood was equivalent to conditions of wind speeds at 10 m height (U10) of 0.27, 0.51 and 0.99 m s-1, respectively, for sweep air flow rates of 2, 5 and 10 L min-1. On the other hand, for higher wind speeds, the emission rates of gas phase-controlled compounds obtained with the flux hood can be considerably underestimated: for instance, at U10 = 5 m s-1, the emission rates of acetic acid inside the flux hood would be approximately 23, 12 and 6 times lower than the emission rates in the field, for sweep air flow rates of 2, 5 and 10 L min-1, respectively. A procedure is presented in

76 FR 40322 - Mt. Hood Meadows Ski Resort Parking Improvements

Science.gov (United States)

2011-07-08

... fleet. Also, the location of the current maintenance shop impedes traffic flow and removes potential... new Sunrise Vehicle Maintenance Shop on the north side of the Sunrise parking lot. DATES: Comments... increasing parking capacity and improving traffic flow in at Mt. Hood Meadows Ski Resort. Parking capacity...

The Black Cultural Ethos and science teachers' practices: A case study exploring how four high school science teachers meet their African American students' needs in science

Science.gov (United States)

Strachan, Samantha L.

The underachievement of African American students in science has been a persistent problem in science education. The achievement patterns of African American students indicate that researchers must take a closer look at the types of practices that are being used to meet these students' needs in science classrooms. Determining why science teachers decide to employ certain practices in their classrooms begins with a careful examination of teachers' beliefs as well as their instructional approaches. The purpose of this study was to explore four urban high school science teachers' beliefs about their African American students' learning needs and to investigate how these teachers go about addressing students' needs in science classrooms. This research study also explored the extent to which teachers' practices aligned with the nine dimensions of an established cultural instructional theory, namely the Black Cultural Ethos. Qualitative research methods were employed to gather data from the four teachers. Artifact data were collected from the teachers and they were interviewed and observed. Believing that their students had academic-related needs as well as needs tied to their learning preferences, the four science teachers employed a variety of instructional strategies to meet their students where they were in learning. Overall, the instructional strategies that the teachers employed to meet their students' needs aligned with five of the nine tenets of the Black Cultural Ethos theory.

Feeding habits of harp and hooded seals in Greenland waters

Directory of Open Access Journals (Sweden)

Finn O Kapel

2000-05-01

Full Text Available Results of stomach contents analyses of harp and hooded seals collected in West Greenland waters in the period 1986-1993 are reviewed, and compared with published data and circumstantial information from local hunters.  The diet of harp seals in this region is variable but consists mainly of pelagic crustaceans (Thysanoessa spp. and Parathemisto libellula and small fish species like capelin (Mallotus villosus, sandeel (Ammodytes spp., polar cod (Boreogadus saida and Arctic cod (Arctogadus glacialis. Species of importance for commercial fisheries in Greenland, such as Northern prawn (Pandalus borealis, Atlantic cod (Gadus morhua, and Greenland halibut (Reinhardtius hippoglossoides play a minor role in the diet of harp seals in this area. Variation in the diet of hooded seals is less well documented, but in addition to the species also taken by harp seals, larger demersal fishes like Greenland halibut, redfish (Sebastes spp., cod, and wolffish (Anarhichas minor are apparently important prey items.

Particle release and control of worker exposure during laboratory-scale synthesis, handling and simulated spills of manufactured nanomaterials in fume hoods

Science.gov (United States)

Fonseca, Ana S.; Kuijpers, Eelco; Kling, Kirsten I.; Levin, Marcus; Koivisto, Antti J.; Nielsen, Signe H.; Fransman, W.; Fedutik, Yijri; Jensen, Keld A.; Koponen, Ismo K.

2018-02-01

Fume hoods are one of the most common types of equipment applied to reduce the potential of particle exposure in laboratory environments. A number of previous studies have shown particle release during work with nanomaterials under fume hoods. Here, we assessed laboratory workers' inhalation exposure during synthesis and handling of CuO, TiO2 and ZnO in a fume hood. In addition, we tested the capacity of a fume hood to prevent particle release to laboratory air during simulated spillage of different powders (silica fume, zirconia TZ-3Y and TiO2). Airborne particle concentrations were measured in near field, far field, and in the breathing zone of the worker. Handling CuO nanoparticles increased the concentration of small particles (control during synthesis and handling of nanomaterials. An appropriate fume hood with adequate sash height and face velocity prevents 98.3% of particles release into the surrounding environment. Care should still be made to consider spills and high cleanliness to prevent exposure via resuspension and inadvertent exposure by secondary routes.

Uncovering Black/African American and Latina/o students' motivation to learn science: Affordances to science identity development

Science.gov (United States)

Mahfood, Denise Marcia

The following dissertation reports on a qualitative exploration that serves two main goals: (1) to qualitatively define and highlight science motivation development of Black/African American and Latina/o students as they learn science in middle school, high school, and in college and (2) to reveal through personal narratives how successful entry and persistence in science by this particular group is linked to the development of their science identities. The targeted population for this study is undergraduate students of color in science fields at a college or university. The theoretical frameworks for this study are constructivist theory, motivation theory, critical theory, and identity theories. The methodological approach is narrative which includes students' science learning experiences throughout the course of their academic lives. I use The Science Motivation Questionnaire II to obtain baseline data to quantitatively assess for motivation to learn science. Data from semi-structured interviews from selected participants were collected, coded, and configured into a story, and emergent themes reveal the important role of science learning in both informal and formal settings, but especially in informal settings that contribute to better understandings of science and the development of science identities for these undergraduate students of color. The findings have implications for science teaching in schools and teacher professional development in science learning.

Revised Master Plan for the Hood River Production Program, Technical Report 2008.

Energy Technology Data Exchange (ETDEWEB)

Oregon Department of Fish and Wildlife; Confederated Tribes of the Warm Springs Reservation

2008-04-28

The Hood River Production Program (HRPP) is a Bonneville Power Administration (BPA) funded program initiated as a mitigation measure for Columbia River hydrosystem effects on anadromous fish. The HRPP began in the early 1990s with the release of spring Chinook and winter steelhead smolts into the basin. Prior to implementation, co-managers, including the Confederated Tribes of the Warm Springs Reservation and the Oregon Department of Fish and Wildlife drafted the Hood River Production Master Plan (O'Toole and ODFW 1991a; O'Toole and ODFW 1991b) and the Pelton Ladder Master Plan (Smith and CTWSR 1991). Both documents were completed in 1991 and subsequently approved by the Council in 1992 and authorized through a BPA-led Environmental Impact Statement in 1996. In 2003, a 10-year programmatic review was conducted for BPA-funded programs in the Hood River (Underwood et al. 2003). The primary objective of the HRPP Review (Review) was to determine if program goals were being met, and if modifications to program activities would be necessary in order to meet or revise program goals. In 2003, an agreement was signed between PacifiCorp and resource managers to remove the Powerdale Dam (RM 10) and associated adult trapping facility by 2010. The HRPP program has been dependant on the adult trap to collect broodstock for the hatchery programs; therefore, upon the dam's removal, some sort of replacement for the trap would be needed to continue the HRPP. At the same time the Hood River Subbasin Plan (Coccoli 2004) was being written and prompted the co-managers to considered future direction of the program. This included revising the numerical adult fish objectives based on the assimilated data and output from several models run on the Hood River system. In response to the Review as well as the Subbasin Plan, and intensive monitoring and evaluation of the current program, the HRPP co-managers determined the spring Chinook program was not achieving the HRPP

Reduction of exposure to ultrafine particles by kitchen exhaust hoods: the effects of exhaust flow rates, particle size, and burner position.

Science.gov (United States)

Rim, Donghyun; Wallace, Lance; Nabinger, Steven; Persily, Andrew

2012-08-15

Cooking stoves, both gas and electric, are one of the strongest and most common sources of ultrafine particles (UFP) in homes. UFP have been shown to be associated with adverse health effects such as DNA damage and respiratory and cardiovascular diseases. This study investigates the effectiveness of kitchen exhaust hoods in reducing indoor levels of UFP emitted from a gas stove and oven. Measurements in an unoccupied manufactured house monitored size-resolved UFP (2 nm to 100 nm) concentrations from the gas stove and oven while varying range hood flow rate and burner position. The air change rate in the building was measured continuously based on the decay of a tracer gas (sulfur hexafluoride, SF(6)). The results show that range hood flow rate and burner position (front vs. rear) can have strong effects on the reduction of indoor levels of UFP released from the stove and oven, subsequently reducing occupant exposure to UFP. Higher range hood flow rates are generally more effective for UFP reduction, though the reduction varies with particle diameter. The influence of the range hood exhaust is larger for the back burner than for the front burner. The number-weighted particle reductions for range hood flow rates varying between 100 m(3)/h and 680 m(3)/h range from 31% to 94% for the front burner, from 54% to 98% for the back burner, and from 39% to 96% for the oven. Copyright © 2012 Elsevier B.V. All rights reserved.

ALARA review for the 202-S plutonium loadout hood stabilization

International Nuclear Information System (INIS)

Patch, R.F.

2000-01-01

This as low as reasonably achievable (ALARA) review provides a description of the engineering and administrative controls used to manage personnel exposures, control contamination levels, and control airborne radioactivity concentrations while conducting stabilization of the Reduction-Oxidation (REDOX) Facility plutonium loadout hood and associated piping, and the isolation of the ER-8 ventilation system

Pedestrian protection integrated in the motor hood; Fussgaengerschutz bei Motorhauben

Energy Technology Data Exchange (ETDEWEB)

Hilfrich, E.; Roettger, R.; Zoernack, M.; Patberg, L. [Vertrieb/Engineering, Fahrzeugtechnik, ThyssenKrupp Steel, Duisburg (Germany)

2005-12-01

New legislation provides for better pedestrian protection in case of collision with motor cars. This is a great challenge in car design. ThyssenKrupp Steel are working on concepts for motor hoods that meet these requirements. Steel is the material of choice as it combines effective energy absorption with an excellent cost-benefit ration. (orig.)

Capture Efficiency of Cooking-Related Fine and Ultrafine Particles by Residential Exhaust Hoods

Energy Technology Data Exchange (ETDEWEB)

Lunden, Melissa M.; Delp, William W.

2014-06-05

Effective exhaust hoods can mitigate the indoor air quality impacts of pollutant emissions from residential cooking. This study reports capture efficiencies (CE) measured for cooking generated particles for scripted cooking procedures in a 121-m3 chamber with kitchenette. CEs also were measured for burner produced CO2 during cooking and separately for pots and pans containing water. The study used four exhaust hoods previously tested by Delp and Singer (Environ. Sci. Technol., 2012, 46, 6167-6173). For pan-frying a hamburger over medium heat on the back burner, CEs for particles were similar to those for burner produced CO2 and mostly above 80percent. For stir-frying green beans in a wok (high heat, front burner), CEs for burner CO2 during cooking varied by hood and airflow: CEs were 34-38percent for low (51?68 L s-1) and 54?72percent for high (109?138 L s-1) settings. CEs for 0.3?2.0 ?m particles during front burner stir-frying were 3?11percent on low and 16?70percent on high settings. Results indicate that CEs measured for burner CO2 are not predictive of CEs of cooking-generated particles under all conditions, but they may be suitable to identify devices with CEs above 80percent both for burner combustion products and for cooking-related particles.

Mathematical modeling of thermal stresses in basic oxygen furnace hood tubes

Science.gov (United States)

Samarasekera, I. V.

1985-06-01

The stress-strain history of Basic Oxygen Furnace hood tubes during thermal cycling has been computed using heat flow and stress analyses. The steady-state temperature distribution in a transverse section of the tube was computed at a location where gas temperature in the hood could be expected to be a maximum. Calculations were performed for peak gas temperatures in the range 1950 to 2480 °C (3500 to 4500 °F). The stress-strain history of an element of material located at the center of the tube hot face was traced for three consecutive cycles using elasto-plastic finite-element analysis. It has been shown that the state of stress in the element alternates between compression and tension as the tube successively heats and cools. Yielding and plastic flow occurs at the end of each half of a given cycle. It was postulated that owing to repctitive yielding, plastic strain energy accumulates causing failure of the tubes by fatigue in the low cycle region. Using fatigue theory a conservative estimate for tube life was arrived at. In-plant observations support this mechanism of failure, and the number of cycles within which tube cracking was observed compares reasonably with model predictions. Utilizing the heat flow and stress models it was recommended that tube life could be enhanced by changing the tube material to ARMCO 17-4 pH or AISI 405 steel or alternatively reconstructing hoods with AISI 316L tubes of reduced thickness. These recommendations were based on the criterion that low-cycle fatigue failure could be averted if the magnitude of the cyclic strain could be reduced or if macroscopic plastic flow could be prevented.

Research and Development for Underground Science at Black Hills State University

Science.gov (United States)

Keeter, Kara

2010-10-01

The development of the Deep Underground Science and Engineering Laboratory (DUSEL) in the former Homestake mine in Lead, South Dakota has greatly spurred interest in science research and development along with education and outreach. Early science activities at Black Hills State University associated with the Sanford Underground Laboratory and DUSEL include radon emanation studies of iron oxide sludge and in situ, and radioactive background and magnetic field measurements. Work is also underway for R&D development for depleted argon-based dark matter detectors, neutrinoless double beta decay experiments, and a liquid scintillator immersion tank for whole-body low-background assays. Students from BHSU and across the state of South Dakota have been working alongside scientists on these and other projects. Teachers from high schools throughout South Dakota have also participated in these projects through the newly formed QuarkNet Center at BHSU.

A Black Feminist Book Club as a Multicultural Professional Development Model for Inservice Secondary Science Teachers

Science.gov (United States)

Hoard, Althea B.

According to science teacher educators, science teachers often struggle to embrace and implement multicultural teaching practices due to limited awareness of the biases, assumptions, and oppressive structures that hinder the success of Students of Color in science classrooms. At its core, teachers lack this awareness due to incomplete understanding of the ways identity markers, such as race, gender, and socioeconomic status, work together to shape one's coming into, understanding of, and success in the sciences. To this end, this case study features four science teachers of diverse backgrounds who engaged in a book club structured to support their understanding of their intersectionality and their identity development. These four science teachers met as a science department to engage with the text Black Feminist Thought (BFT) (Collins, 2009) and other critical texts over a six-month period at a New York City, charter high school. The findings revealed the ways racial stereotypes, propagated by many factors--including images of scientists, relationships with teachers, and expectations of peers and family--influenced their coming into and understanding of science. Additionally, the findings show the ways teachers discovered their intersectionality--particularly the interplay of their race and gender--influenced their approaches to teaching science. As teachers learned about the multidimensionality of their positional identities, they became aware of discriminatory structures of power that disadvantage their Black female science students and reported implementing more student-centered pedagogical practices. Altogether, this study offers a professional development model for building critical consciousness with inservice secondary science teachers.

Science self-efficacy of African Americans enrolled in freshman level physical science courses in two historically black institutions

Science.gov (United States)

Prihoda, Belinda Ann

2011-12-01

Science education must be a priority for citizens to function and be productive in a global, technological society. African Americans receive fewer science degrees in proportion to the Caucasian population. The primary purposes of this study were to determine the difference between the pretest and posttest science self-efficacy scores of African-American nonscience majors, the difference between the pretest and posttest science self-efficacy scores of African-American science majors, the relationship between science self-efficacy and course grade, the relationship between gender and science self-efficacy score, and the relationship between science self-efficacy score and course withdrawal. This study utilized a Likert survey instrument. All participants were enrolled in freshman level courses in the physical sciences at a historically black institution: a college or university. Participants completed the pretest survey within two weeks after the 12th class day of the semester. Initially, 458 participants completed the pretest survey. The posttest was administered within two weeks before the final exam. Only 245 participants completed the posttest survey. Results indicate that there is a difference in science self-efficacy of science majors and nonscience majors. There was no significant difference between the pretest and posttest science self-efficacy scores of African-American science majors and nonscience majors. There was no significant relationship between science self-efficacy and course grade, gender and science self-efficacy score, and course withdrawal and science self-efficacy score.

Capture efficiency of cooking-related fine and ultrafine particles by residential exhaust hoods.

Science.gov (United States)

Lunden, M M; Delp, W W; Singer, B C

2015-02-01

Effective exhaust hoods can mitigate the indoor air quality impacts of pollutant emissions from residential cooking. This study reports capture efficiencies (CE) measured for cooking-generated particles for scripted cooking procedures in a 121-m3 chamber with kitchenette. CEs also were measured for burner produced CO2 during cooking and separately for pots and pans containing water. The study used four exhaust hoods previously tested by Delp and Singer (Environ. Sci. Technol., 2012, 46, 6167-6173). For pan-frying a hamburger over medium heat on the back burner, CEs for particles were similar to those for burner produced CO2 and mostly above 80%. For stir-frying green beans in a wok (high heat, front burner), CEs for burner CO2 during cooking varied by hood and airflow: CEs were 34-38% for low (51-68 l/s) and 54-72% for high (109-138 l/s) settings. CEs for 0.3-2.0 μm particles during front burner stir-frying were 3-11% on low and 16-70% on high settings. Results indicate that CEs measured for burner CO2 are not predictive of CEs of cooking-generated particles under all conditions, but they may be suitable to identify devices with CEs above 80% both for burner combustion products and for cooking-related particles. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Archeological Testing Fort Hood: 1994-1995. Volume 2

Science.gov (United States)

1996-10-01

ASSOCI TES, INC. (662-22) Archeological Testing at Fort Hood. 1994-199.5 569 -48-1941.1080-134 1935 -058 Figure 7.17 Selected Perforator Types: Awl and...Department of Anthropology, University of Arkansas. Huskey, V. 1935 An Archeological Survey of the Nueces Canyon of Texas, Bulletin of the Texas... epr 064lL.Tan I lms expected 08-FH1 Yellow 4 expected expedctd cd .9 15.Q W n• I less M 0 ~ *~Tax~on Total Total Inmr 53 nac na Vertebra.es 1. FcAuifnm

Hood River Steelhead Genetics Study; Relative Reproductive Success of Hatchery and Wild Steelhead in the Hood River, Final Report 2002-2003.

Energy Technology Data Exchange (ETDEWEB)

Blouin, Michael

2003-05-01

There is a considerable interest in using hatcheries to speed the recovery of wild populations. The Bonneville Power Administration (BPA), under the authority of the Northwest Power Planning Act, is currently funding several hatchery programs in the Columbia Basin as off-site mitigation for impacts to salmon and steelhead caused by the Columbia River federal hydropower system. One such project is located on the Hood River, an Oregon tributary of the Columbia. These hatchery programs cost the region millions of dollars. However, whether such programs actually improve the status of wild fish remains untested. The goal of this project was to evaluate the effectiveness of the Hood River hatchery program as required by the Northwest Power Planning Council Fish and Wildlife Program, by the Oregon Plan for Coastal Salmonids, by NMFS ESA Section 4(d) rulings, and by the Oregon Department of Fish and Wildlife (ODFW) Wild Fish Management Policy (OAR 635-07-525 through 529) and the ODFW Hatchery Fish Gene Resource Management Policy (OAR 635-07-540 through 541). The Hood River supports two populations of steelhead, a summer run and a winter run. They spawn only above the Powerdale Dam, which is a complete barrier to all salmonids. Since 1991 every adult passed above the dam has been measured, cataloged and sampled for scales. Therefore, we have a DNA sample from every adult steelhead that went over the dam to potentially spawn in the Hood River from 1991 to the present. Similar numbers of hatchery and wild fish have been passed above the dam during the last decade. During the 1990's 'old' domesticated hatchery stocks of each run (multiple generations in the hatchery, out-of-basin origin; hereafter H{sub old}) were phased out, and conservation hatchery programs were started for the purpose of supplementing the two wild populations (hereafter 'new' hatchery stocks, H{sub new}). These samples gave us the unprecedented ability to estimate, via

Carbon Dioxide Exposure Resulting From Hood Protective Equipment Used in Joint Arthroplasty Surgery.

Science.gov (United States)

Patel, Suhani; Fine, Janelle M; Lim, Michael J; Copp, Steven N; Rosen, Adam S; West, John B; Prisk, G Kim

2017-08-01

To protect both the surgeon and patient during procedures, hooded protection shields are used during joint arthroplasty procedures. Headache, malaise, and dizziness, consistent with increased carbon dioxide (CO 2 ) exposure, have been anecdotally reported by surgeons using hoods. We hypothesized that increased CO 2 concentrations were causing reported symptoms. Six healthy subjects (4 men) donned hooded protection, fan at the highest setting. Arm cycle ergometry at workloads of 12 and 25 watts (W) simulated workloads encountered during arthroplasty. Inspired O 2 and CO 2 concentrations at the nares were continuously measured at rest, 12 W, and 25 W. At each activity level, the fan was deactivated and the times for CO 2 to reach 0.5% and 1.0% were measured. At rest, inspired CO 2 was 0.14% ± 0.04%. Exercise had significant effect on CO 2 compared with rest (0.26% ± 0.08% at 12 W, P = .04; 0.31% ± 0.05% at 25 W, P = .003). Inspired CO 2 concentration increased rapidly with fan deactivation, with the time for CO 2 to increase to 0.5% and 1.0% after fan deactivation being rapid but variable (0.5%, 12 ± 9 seconds; 1%, 26 ± 15 seconds). Time for CO 2 to return below 0.5% after fan reactivation was 20 ± 37 seconds. During simulated joint arthroplasty, CO 2 remained within Occupational Safety and Health Administration (OSHA) standards with the fan at the highest setting. With fan deactivation, CO 2 concentration rapidly exceeds OSHA standards. Copyright © 2017 Elsevier Inc. All rights reserved.

Study the velocity and pressure exerted in front of the filter surface in the kitchen hood system by using ANSYS

Science.gov (United States)

Asmuin, Norzelawati; Pairan, M. Rasidi; Isa, Norasikin Mat; Sies, Farid

2017-04-01

Commercial kitchen hood ventilation system is a device used to capture and filtered the plumes from cooking activities in the kitchen area. Nowadays, it is very popular in the industrial sector such as restaurant and hotel to provide hygiene food. This study focused at the KSA filter part which installed in the kitchen hood system, the purpose of this study is to identify the critical region which indicated by observing the velocity and pressure of plumes exerted at of KSA filter. It is important to know the critical location of the KSA filter in order to install the nozzle which will helps increase the filtration effectiveness. The ANSYS 16.1 (FLUENT) software as a tool used to simulate the kitchen hood systems which consist of KSA filter. The commercial kitchen hood system model has a dimension 700 mm width, 1600 mm length and 555 mm height. The system has two inlets and one outlet. The velocity of the plumes is set to be 0.235m/s and the velocity of the inlet capture jet is set to be 1.078m/s. The KSA filter is placed 45 degree from the y axis. The result shows the plumes has more tendency flowing pass through at the bottom part of KSA filter.

Hood River Production Program Monitoring and Evaluation (M&E) - Confederated Tribes of Warm Springs : Annual Report For Fiscal Year, October 2007 – September 2008.

Energy Technology Data Exchange (ETDEWEB)

Gerstenberger, Ryan [Confederated Tribes of Warm Springs Reservation

2009-07-27

This progress report describes work performed by the Confederated Tribes of Warm Springs (CTWSRO) portion of the Hood River Production Program Monitoring and Evaluation Project (HRPP) during the 2008 fiscal year. A total of 64,736 hatchery winter steelhead, 12,108 hatchery summer steelhead, and 68,426 hatchery spring Chinook salmon smolts were acclimated and released in the Hood River basin during the spring. The HRPP exceeded program goals for a release of and 50,000 winter steelhead but fell short of the steelhead release goals of 30,000 summer steelhead and 75,000 spring Chinook in 2008. Passive Integrated Transponders (PIT) tags were implanted in 6,652 hatchery winter steelhead, and 1,196 hatchery summer steelhead, to compare migratory attributes and survival rates of hatchery fish released into the Hood River. Water temperatures were recorded at six locations within the Hood River subbasin to monitor for compliance with Oregon Department of Environmental Quality water quality standards. A preseason spring Chinook salmon adult run forecast was generated, which predicted an abundant return adequate to meet escapement goal and brood stock needs. As a result the tribal and sport fisheries were opened. A tribal creel was conducted from May 22 to July 18 during which an estimated 172 spring Chinook were harvested. One hundred sixteen Spring Chinook salmon redds were observed and 72 carcasses were inspected on 19.4 miles of spawning grounds throughout the Hood River Basin during 2008. Annual salvage operations were completed in two irrigation canals resulting in the liberation of 1,641 fish back to the Hood River.

How the Cobra Got Its Flesh-Eating Venom: Cytotoxicity as a Defensive Innovation and Its Co-Evolution with Hooding, Aposematic Marking, and Spitting

Directory of Open Access Journals (Sweden)

Nadya Panagides

2017-03-01

Full Text Available The cytotoxicity of the venom of 25 species of Old World elapid snake was tested and compared with the morphological and behavioural adaptations of hooding and spitting. We determined that, contrary to previous assumptions, the venoms of spitting species are not consistently more cytotoxic than those of closely related non-spitting species. While this correlation between spitting and non-spitting was found among African cobras, it was not present among Asian cobras. On the other hand, a consistent positive correlation was observed between cytotoxicity and utilisation of the defensive hooding display that cobras are famous for. Hooding and spitting are widely regarded as defensive adaptations, but it has hitherto been uncertain whether cytotoxicity serves a defensive purpose or is somehow useful in prey subjugation. The results of this study suggest that cytotoxicity evolved primarily as a defensive innovation and that it has co-evolved twice alongside hooding behavior: once in the Hemachatus + Naja and again independently in the king cobras (Ophiophagus. There was a significant increase of cytotoxicity in the Asian Naja linked to the evolution of bold aposematic hood markings, reinforcing the link between hooding and the evolution of defensive cytotoxic venoms. In parallel, lineages with increased cytotoxicity but lacking bold hood patterns evolved aposematic markers in the form of high contrast body banding. The results also indicate that, secondary to the evolution of venom rich in cytotoxins, spitting has evolved three times independently: once within the African Naja, once within the Asian Naja, and once in the Hemachatus genus. The evolution of cytotoxic venom thus appears to facilitate the evolution of defensive spitting behaviour. In contrast, a secondary loss of cytotoxicity and reduction of the hood occurred in the water cobra Naja annulata, which possesses streamlined neurotoxic venom similar to that of other aquatic elapid snakes (e

How the Cobra Got Its Flesh-Eating Venom: Cytotoxicity as a Defensive Innovation and Its Co-Evolution with Hooding, Aposematic Marking, and Spitting.

Science.gov (United States)

Panagides, Nadya; Jackson, Timothy N W; Ikonomopoulou, Maria P; Arbuckle, Kevin; Pretzler, Rudolf; Yang, Daryl C; Ali, Syed A; Koludarov, Ivan; Dobson, James; Sanker, Brittany; Asselin, Angelique; Santana, Renan C; Hendrikx, Iwan; van der Ploeg, Harold; Tai-A-Pin, Jeremie; van den Bergh, Romilly; Kerkkamp, Harald M I; Vonk, Freek J; Naude, Arno; Strydom, Morné A; Jacobsz, Louis; Dunstan, Nathan; Jaeger, Marc; Hodgson, Wayne C; Miles, John; Fry, Bryan G

2017-03-13

The cytotoxicity of the venom of 25 species of Old World elapid snake was tested and compared with the morphological and behavioural adaptations of hooding and spitting. We determined that, contrary to previous assumptions, the venoms of spitting species are not consistently more cytotoxic than those of closely related non-spitting species. While this correlation between spitting and non-spitting was found among African cobras, it was not present among Asian cobras. On the other hand, a consistent positive correlation was observed between cytotoxicity and utilisation of the defensive hooding display that cobras are famous for. Hooding and spitting are widely regarded as defensive adaptations, but it has hitherto been uncertain whether cytotoxicity serves a defensive purpose or is somehow useful in prey subjugation. The results of this study suggest that cytotoxicity evolved primarily as a defensive innovation and that it has co-evolved twice alongside hooding behavior: once in the Hemachatus + Naja and again independently in the king cobras ( Ophiophagus ). There was a significant increase of cytotoxicity in the Asian Naja linked to the evolution of bold aposematic hood markings, reinforcing the link between hooding and the evolution of defensive cytotoxic venoms. In parallel, lineages with increased cytotoxicity but lacking bold hood patterns evolved aposematic markers in the form of high contrast body banding. The results also indicate that, secondary to the evolution of venom rich in cytotoxins, spitting has evolved three times independently: once within the African Naja , once within the Asian Naja , and once in the Hemachatus genus. The evolution of cytotoxic venom thus appears to facilitate the evolution of defensive spitting behaviour. In contrast, a secondary loss of cytotoxicity and reduction of the hood occurred in the water cobra Naja annulata , which possesses streamlined neurotoxic venom similar to that of other aquatic elapid snakes (e.g., hydrophiine

Construction and Operation of a Ventilated Hood System for Measuring Greenhouse Gas and Volatile Organic Compound Emissions from Cattle

Directory of Open Access Journals (Sweden)

Yongjing Zhao

2011-12-01

Full Text Available Recent interest in greenhouse gas emissions from ruminants, such as cattle, has spawned a need for affordable, precise, and accurate methods for the measurement of gaseous emissions arising from enteric fermentation. A new head hood system for cattle designed to capture and quantify emissions was recently developed at the University of California, Davis. The system consists of two head hoods, two vacuum pumps, and an instrumentation cabinet housing the required data collection equipment. This system has the capability of measuring carbon dioxide, methane, ethanol, methanol, water vapor, nitrous oxide, acetic acid emissions and oxygen consumption in real-time. A unique aspect of the hoods is the front, back, and sides are made of clear polycarbonate sheeting allowing the cattle a full range of vision during gas sampling. Recovery rates for these slightly negative pressure chambers were measured ranging from 97.6 to 99.3 percent. This system can capture high quality data for use in improving emission inventories and evaluating gaseous emission mitigation strategies.

Subscale hood seal test topical report

Energy Technology Data Exchange (ETDEWEB)

Versteeg, J.L.; Herold, B.A.; McClintic, J.K.; Schmall, R.A.; Hoetzl, M.

1991-09-06

To maximize the transfer of heat from the recirculated gases to the scrap, it is essential to percolate as much of the gases as possible through the scrap. To accomplish this flow path and avoid the bypassing of hot gas around the scrap, the seal between the preheater hood and the scrap bucket must be relatively tight. These tests which are described in this report were designed to measure the performance of several possible seal designs under simulated operating conditions. At the conclusion of the tests, one design was recommended as the primary arrangement with another design considered as an alternate. Both designs met the criteria of low leakage but one design was preferred due an expected greater resistance to wear. The test results also provided valuable information for estimating seal leakage in the full scale installation.

Influence of impact speed on head and brain injury outcome in vulnerable road user impacts to the car hood.

Science.gov (United States)

Fredriksson, Rikard; Zhang, Liying; Boström, Ola; Yang, King

2007-10-01

EuroNCAP and regulations in Europe and Japan evaluate the pedestrian protection performance of cars. The test methods are similar and they all have requirements for the passive protection of the hood area at a pedestrian to car impact speed of 40 km/h. In Europe, a proposal for a second phase of the regulation mandates a brake-assist system along with passive requirements. The system assists the driver in optimizing the braking performance during panic braking, resulting in activation only when the driver brakes sufficiently. In a European study this was estimated to occur in about 50% of pedestrian accidents. A future system for brake assistance will likely include automatic braking, in response to a pre-crash sensor, to avoid or mitigate injuries of vulnerable road users. An important question is whether these systems will provide sufficient protection, or if a parallel, passive pedestrian protection system will be necessary. This study investigated the influence of impact speed on head and brain injury risk, in impacts to the carhood. One car model was chosen and a rigid adjustable plate was mounted under the hood. Free-flying headform impacts were carried out at 20 and 30 km/h head impact velocities at different under-hood distances, 20 to 100 mm; and were compared to earlier tests at 40 km/h. The EEVC WG17 adult pedestrian headform was used for non-rotating tests and a Hybrid III adult 50th percentile head was used for rotational tests where linear and rotational acceleration was measured. Data from the rotational tests was used as input to a validated finite element model of the human head, the Wayne State University Head Injury Model (WSUHIM). The model was utilized to assess brain injury risk and potential injury mechanism in a pedestrian-hood impact. Although this study showed that it was not necessarily true that a lower HIC value reduced the risk for brain injury, it appeared, for the tested car model, under-hood distances of 60 mm in 20 km/h and 80 mm

Teachers' perceptions of the effectiveness of an urban health sciences curriculum in closing the Black-White test score gap: A participatory case study

Science.gov (United States)

Prince, Joan Marie

1999-12-01

Over the past years, progress in Black academic achievement, particularly in the area of science, has generally slowed or ceased. According to the 1994 NAEP assessment, twelfth-grade Black students are performing at the level of White eighth-grade students in the discipline of science (Department of Education, 1996). These students, in their last year of required schooling, are about to graduate, yet they lag at least four years behind their white counterparts in science achievement. Despite the establishment and implementation of numerous science intervention programs, Black students still suffer from a disparate gap in standardized test score achievement. The purpose of this research is to investigate teachers' perceptions of the effectiveness of an urban sciences intervention tool that was designed to assist in narrowing the Black-White science academic achievement gap. Specifically, what factors affect teachers' personal sense of instructional efficacy, and how does this translate into their outcome expectancy for student academic success? A multiple-case, replicative design, grounded in descriptive theory, was selected for the study. Multiple sources of evidence were queried to provide robust findings. These sources included a validated health sciences self-efficacy instrument, an interview protocol, a classroom observation, and a review of archival material that included case study participants' personnel files and meeting minutes. A cross-comparative analytic approach was selected for interpretation (Yin, 1994). Findings indicate that teachers attribute the success or failure of educational intervention tools in closing the Black-White test score gap to a variety of internal and external factors. These factors included a perceived lack of both monetary and personal support by the school leadership, as well as a perceived lack of parental involvement which impacted negatively on student achievement patterns. The case study participants displayed a depressed

Beyond 2001: a silvicultural odyssey to sustaining terrestrial and aquatic ecosystems? Proceedings of the 2001 national silviculture workshop, May 6-10, Hood River, Oregon.

Science.gov (United States)

Sharon Parker; Susan Stevens. Hummel

2002-01-01

The 2001 National Silviculture Workshop was held in Hood River, Oregon, and hosted by the Mt. Hood National Forest, the Gifford Pinchot National Forest, and the Pacific Northwest Research Station. The Washington Office Vegetation Management and Protection Research and Forest and Grassland staffs are ongoing sponsors of the biennial workshop, which began in 1973 in...

An Investigation of How Black STEM Faculty at Historically Black Colleges and Universities Approach the National Science Foundation Merit Review Process

Science.gov (United States)

Rankins, Falcon

This qualitative inquiry explored the ways in which US-born, Black faculty member participants in science, technology, engineering, and mathematics (STEM) disciplines at Historically Black Colleges and Universities (HBCUs) interact with the National Science Foundation (NSF). Eight Black HBCU STEM faculty members with a range of involvement in NSF-related activities were individually interviewed. Topics of discussion with participants included their prior experiences with NSF, their understanding of the merit review process, and their understanding of their personal and institutional relationships with NSF and the STEM community. Two broad findings emerged from the conversations. The first was that issues of communities and social identity were important to the participants' work as research scientists. Participants prioritized advancing people and communities over advancing the knowledge of ambiguous, disembodied scientific disciplines, and some participants were motivated by interests in social justice. However, participants maintained strong identities as scientists and the discussions provided no evidence that other social factors influenced their application of the scientific method. The second major finding dealt with the role participants perceived their institutions playing in their involvement with NSF. All participants described challenges associated with pursuing research in HBCU environments and, in some cases, the institutional challenges served as the motivation for participants' projects, with varying consequences. The participants' discussions about their institutions also raised important questions about how well-aligned participants' visions are with the visions of their institutional leadership, regarding how research should be incorporated into the HBCU mission. Finally, this study developed and refined a theoretical framework for explaining the underrepresentation of HBCUs in NSF funding streams. In developing this framework, a brief history of

Carbon epoxy front hood for an electrical city vehicle

Directory of Open Access Journals (Sweden)

Bere Paul

2017-01-01

Full Text Available In the last decade fiber-reinforced polymer (FRP had a very impressive development. Due to its physical and mechanical properties, this material is used in many high-end domains such as: aerospace, aviation, automotive, medical, engineering or building constructions. In the last period FRP are being intensely used in the automotive industry especially for the chassis manufacturing and other vehicle structural components. In this paper, the authors present the model of a carbon epoxy front hood of a two-passenger electrical car which is specially designed in urban area and which makes use of advanced FRP manufacturing.

The gut microbiome of hooded cranes (Grus monacha) wintering at Shengjin Lake, China.

Science.gov (United States)

Zhao, Guanghong; Zhou, Lizhi; Dong, Yuanqiu; Cheng, Yuanyuan; Song, Yunwei

2017-06-01

Gut microbes of animals play critical roles in processes such as digestion and immunity. Therefore, identifying gut microbes will shed light on understanding the annual life of animal species, particularly those that are threatened or endangered. In the present study, we conducted nucleotide sequence analyses of the 16S rRNA genes of gut microbiome of the hooded cranes (Grus monacha) wintering at Shengjin Lake, China, by Illumina high-throughput sequencing technology. We acquired 503,398 high-quality sequences and 785 operational taxonomic units (OTUs) from 15 fecal samples from different cranes, representing 22 phyla that were dominated by Firmicutes, Proteobacteria, and Actinobacteria. A total of 305 genera were identified that were dominated by Clostridium, Lysinibacillus, and Enterobacter. The core gut microbiome comprised 26 genera, including many probiotic species such as Clostridium, Bacillus, Cellulosilyticum, and Cellulomonas that could catabolize cellulose. The findings reported here contribute to our knowledge of the microbiology of hooded cranes and will likely advance efforts to protect waterbirds that inhabit Shengjin Lake Reserve during winter. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Measurements and predictions of hooded crow (Corvus corone cornix) call propagation over open field habitats

DEFF Research Database (Denmark)

Jensen, Kenneth Kragh; Larsen, Ole Næsbye; Attenborough, Keith

2008-01-01

In a study of hooded crow communication over open fields an excellent correspondence is found between the attenuation spectra predicted by a "turbulence-modified ground effect plus atmospheric absorption" model, and crow call attenuation data. Sound propagation predictions and background noise...

End-use energy characterization and conservation potentials at DoD Facilities: An analysis of electricity use at Fort Hood, Texas

Energy Technology Data Exchange (ETDEWEB)

Akbari, H.; Konopacki, S.

1995-05-01

This report discusses the application of the LBL`s End-use Disaggregation Algorithm (EDA) to a DoD installation and presents hourly reconciled end-use data for all major building types and end uses. The project initially focused on achieving these objectives and pilot-testing the methodology at Fort Hood, Texas. Fort Hood, with over 5000 buildings was determined to have representative samples of nearly all of the major building types in use on DoD installations. These building types at Fort Hood include: office, administration, vehicle maintenance, shop, hospital, grocery store, retail store, car wash, church, restaurant, single-family detached housing, two and four-plex housings, and apartment building. Up to 11 end uses were developed for each prototype, consisting of 9 electric and 2 gas; however, only electric end uses were reconciled against known data and weather conditions. The electric end uses are space cooling, ventilation, cooking, miscellaneous/plugs, refrigeration, exterior lighting, interior lighting, process loads, and street lighting. The gas end uses are space heating and hot water heating. Space heating energy-use intensities were simulated only. The EDA was applied to 10 separate feeders from the three substations at Fort Hood. The results from the analyses of these ten feeders were extrapolated to estimate energy use by end use for the entire installation. The results show that administration, residential, and the bar-rack buildings are the largest consumers of electricity for a total of 250GWh per year (74% of annual consumption). By end use, cooling, ventilation, miscellaneous, and indoor lighting consume almost 84% of total electricity use. The contribution to the peak power demand is highest by residential sector (35%, 24 MW), followed by administration buildings (30%), and barrack (14%). For the entire Fort Hood installation, cooling is 54% of the peak demand (38 MW), followed by interior lighting at 18%, and miscellaneous end uses by 12%.

MOUNT HOOD WILDERNESS AND ADJACENT AREAS, OREGON.

Science.gov (United States)

Keith, T.E.C.; Causey, J.D.

1984-01-01

A mineral survey of the Mount Hood Wilderness, Oregon, was conducted. Geochemical data indicate two areas of substantiated mineral-resource potential containing weak epithermal mineralization: an area of the north side of Zigzag Mountain where vein-type lead-zinc-silver deposits occur and an area of the south side of Zigzag Mountain, where the upper part of a quartz diorite pluton has propylitic alteration associated with mineralization of copper, gold, silver, lead, and zinc in discontinuous veins. Geothermal-resource potential for low- to intermediate-temperature (less than 248 degree F) hot-water systems in the wilderness is probable in these areas. Part of the wilderness is classified as a Known Geothermal Resource Area (KGRA), which is considered to have probable geothermal-resource potential, and two parts of the wilderness have been included in geothermal lease areas.

Agriculture and Rural Development on Fort Hood Lands, 1849-1942: National Register Assessments of 710 Historic Archeological Properties

National Research Council Canada - National Science Library

Freeman, Martha

2001-01-01

In 1999, historians consulting with Prewitt & Associates, Inc., conducted archival research for the purpose of developing historic contexts relevant to the Fort Hood lands taken during the 1940s acquisition...

A review of Brucella infection in marine mammals, with special emphasis on Brucella pinnipedialis in the hooded seal (Cystophora cristata)

Science.gov (United States)

2011-01-01

Brucella spp. were isolated from marine mammals for the first time in 1994. Two novel species were later included in the genus; Brucella ceti and Brucella pinnipedialis, with cetaceans and seals as their preferred hosts, respectively. Brucella spp. have since been isolated from a variety of marine mammals. Pathological changes, including lesions of the reproductive organs and associated abortions, have only been registered in cetaceans. The zoonotic potential differs among the marine mammal Brucella strains. Many techniques, both classical typing and molecular microbiology, have been utilised for characterisation of the marine mammal Brucella spp. and the change from the band-based approaches to the sequence-based approaches has greatly increased our knowledge about these strains. Several clusters have been identified within the B. ceti and B. pinnipedialis species, and multiple studies have shown that the hooded seal isolates differ from other pinniped isolates. We describe how different molecular methods have contributed to species identification and differentiation of B. ceti and B. pinnipedialis, with special emphasis on the hooded seal isolates. We further discuss the potential role of B. pinnipedialis for the declining Northwest Atlantic hooded seal population. PMID:21819589

A review of Brucella infection in marine mammals, with special emphasis on Brucella pinnipedialis in the hooded seal (Cystophora cristata

Directory of Open Access Journals (Sweden)

Nymo Ingebjørg H

2011-08-01

Full Text Available Abstract Brucella spp. were isolated from marine mammals for the first time in 1994. Two novel species were later included in the genus; Brucella ceti and Brucella pinnipedialis, with cetaceans and seals as their preferred hosts, respectively. Brucella spp. have since been isolated from a variety of marine mammals. Pathological changes, including lesions of the reproductive organs and associated abortions, have only been registered in cetaceans. The zoonotic potential differs among the marine mammal Brucella strains. Many techniques, both classical typing and molecular microbiology, have been utilised for characterisation of the marine mammal Brucella spp. and the change from the band-based approaches to the sequence-based approaches has greatly increased our knowledge about these strains. Several clusters have been identified within the B. ceti and B. pinnipedialis species, and multiple studies have shown that the hooded seal isolates differ from other pinniped isolates. We describe how different molecular methods have contributed to species identification and differentiation of B. ceti and B. pinnipedialis, with special emphasis on the hooded seal isolates. We further discuss the potential role of B. pinnipedialis for the declining Northwest Atlantic hooded seal population.

Harvest-related edge effects on prey availability and foraging of hooded warblers in a bottomland hardwood forest.

Energy Technology Data Exchange (ETDEWEB)

John Kilgo

2005-04-20

The effects of harvest-created canopy gaps in bottomland hardwood forests on arthropod abundance and, hence, the foraging ecology of birds are poorly understood. I predicted that arthropod abundance would be high near edges of group-selection harvest gaps and lower in the surrounding forest, and that male Hooded Warblers (Wilsonia citrina) foraging near gaps would find more prey per unit time than those foraging in the surrounding forest. In fact, arthropod abundance was greater >100 m from a gap edge than at 0-30 m or 30-100 m from an edge, due to their abundance on switchcane (Arundinaria gigantea); arthropods did not differ in abundance among distances from gaps on oaks (Quercus spp.) or red maple (Acer rubrum). Similarly, Hooded Warbler foraging attack rates were not higher near gap edges: when foraging for fledglings, attack rate did not differ among distances from gaps, but when foraging for themselves, attack rates actually were lower 0-30 m from gap edges than 30-100 m or >100 m from a gap edge. Foraging attack rate was positively associated with arthropod abundance. Hooded Warblers apparently encountered fewer prey and presumably foraged less efficiently where arthropods were least abundant, i.e., near gaps. That attack rates among birds foraging for fledglings were not affected by distance from gap (and hence arthropod abundance) suggests that prey availability may not be limiting at any location across the forest, despite the depressing effects of gaps on arthropod abundance.

42 CFR 84.198 - Half-mask facepieces, full facepieces, mouthpieces, hoods, and helmets; fit; minimum requirements.

Science.gov (United States)

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Half-mask facepieces, full facepieces, mouthpieces... APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.198 Half-mask facepieces, full facepieces, mouthpieces, hoods, and helmets; fit; minimum requirements. (a) Half-mask facepieces...

Bonneville - Hood River Vegetation Management Environmental Assessment

Energy Technology Data Exchange (ETDEWEB)

N/A

1998-08-01

To maintain the reliability of its electrical system, BPA, in cooperation with the U.S. Forest Service, needs to expand the range of vegetation management options used to clear unwanted vegetation on about 20 miles of BPA transmission line right-of-way between Bonneville Dam and Hood River; Oregon, within the Columbia Gorge National Scenic Area (NSA). We propose to continue controlling undesirable vegetation using a program of Integrated Vegetation Management (IVM) which includes manual, biological and chemical treatment methods. BPA has prepared an Environmental Assessment (EA) (DOE/EA-1257) evaluating the proposed project. Based on the analysis in the EA, BPA has determined that the proposed action is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969. Therefore, the preparation of an Environmental Impact Statement (EIS) is not required and BPA is issuing this FONSI.

Computer modeling of fluid flow and combustion in the ISV [In Situ Vitrification] confinement hood

International Nuclear Information System (INIS)

Johnson, R.W.; Paik, S.

1990-09-01

Safety and suitability objectives for the application of the In Situ Vitrification (ISV) technology at the INEL require that the physical processes involved in ISVV be modeled to determine their operational behavior. The mathematical models that have been determined to address the modeling needs adequately for the ISV analysis package are detailed elsewhere. The present report is concerned with the models required for simulating the reacting flow that occurs in the ISV confinement hood. An experimental code named COYOTE has been secured that appears adequate to model the combustion in the confinement hood. The COYOTE code is a two-dimensional, transient, compressible, Eulerian, gas dynamics code for modeling reactive flows. It recognizes nonuniform Cartesian and cylindrical geometry and is based on the ICE (Implicit Continuous-fluid Eulerian) family of solution methods. It includes models for chemical reactions based on chemical kinetics as well as equilibrium chemistry. The mathematical models contained in COYOTE, their discrete analogs, the solution procedure, code structure and some test problems are presented in the report. 12 refs., 17 figs., 6 tabs

Cassini ISS Observations Of The Early Stages Of The Formation Of Titan's South Polar Hood And Vortex In 2012

Science.gov (United States)

West, Robert A.; Del Genio, A.; Perry, J.; Ingersoll, A. P.; Turtle, E. P.; Porco, C.; Ovanessian, A.

2012-10-01

Northern spring equinox on Titan occurred on August 11, 2009. In March of 2012 the Imaging Science Subsystem (ISS) on the Cassini spacecraft saw the first evidence for the formation of a polar hood in the atmosphere above Titan’s south pole. Views of the limb showed an optical thickening primarily at about 360 km altitude across a few degrees of latitude centered on the pole. Images of Titan in front of Saturn provide a nearly direct measure of the line-of-sight optical depth as a function of latitude and altitude from about 250 km and higher. Two or more distinct layers are seen, both near the pole and at other latitudes. The highest of these, near 360 km altitude, hosts the embryonic polar hood. On June 27, 2012 ISS observed the pole from high latitude. These images show a distinct and unusual cloudy patch, elongated and not centered on the pole and with an elevated perimeter. The morphology and color indicate an unfamiliar (for Titan) composition and dynamical regime. The interior of the feature consists of concentrations of cloud/haze organized on spatial scales of tens of kilometers. Its morphology is reminiscent of the open cellular convection sometimes seen in the atmospheric boundary layer over Earth’s oceans under conditions of large-scale subsidence. Unlike Earth, where such convection is forced by large surface heat fluxes or the onset of drizzle, convection at 360 km on Titan is more likely to be driven from above by radiative cooling. During the 9 hours we observed Titan, this feature completed a little over one rotation around the pole, providing direct evidence for a polar vortex rotating at a rate roughly consistent with angular-momentum-conserving flow for air displaced from the equator. Part of this work was performed by the Jet Propulsion Laboratory, California Institute of Technology.

Emissions & Measurements - Black Carbon | Science ...

Science.gov (United States)

Emissions and Measurement (EM) research activities performed within the National Risk Management Research Lab NRMRL) of EPA's Office of Research and Development (ORD) support measurement and laboratory analysis approaches to accurately characterize source emissions, and near source concentrations of air pollutants. They also support integrated Agency research programs (e.g., source to health outcomes) and the development of databases and inventories that assist Federal, state, and local air quality managers and industry implement and comply with air pollution standards. EM research underway in NRMRL supports the Agency's efforts to accurately characterize, analyze, measure and manage sources of air pollution. This pamphlet focuses on the EM research that NRMRL researchers conduct related to black carbon (BC). Black Carbon is a pollutant of concern to EPA due to its potential impact on human health and climate change. There are extensive uncertainties in emissions of BC from stationary and mobile sources. Emissions and Measurement (EM) research activities performed within the National Risk Management Research Lab NRMRL) of EPA's Office of Research and Development (ORD)

Book review: Black bass diversity: Multidisciplinary science for conservation

Science.gov (United States)

Jelks, Howard L.

2016-01-01

These proceedings are from the third symposium dedicated to management and conservation of black basses in the genus Micropterus. The first symposium was held in 1975 (R. H. Stroud and H. Clepper. Black Bass Biology and Management. Washington (DC): Sport Fishing Institute) followed 25 years later by Black Bass 2000 (D. P. Philipp and M. S. Ridgway. 2002. Black Bass: Ecology, Conservation, and Management. Bethesda (MD): American Fisheries Society). Although the previous books discussed conservation of genetic variation and distinct strains of basses, the bulk of the papers in those tomes emphasized management of largemouth and smallmouth bass. In contrast, this third symposium is focused on the rarer bass species and challenges for their successful management.

Factors influencing success of metal to plastic conversion programs for under-hood applications

Energy Technology Data Exchange (ETDEWEB)

Male, L.J. [Amoco Chemicals Polymers Business Group, Alpharetta, GA (United States); Desai, K.C.

1995-12-31

This paper compares high performance engineering polymers available today for under-hood applications. It includes an example of an end cap showing value-added capabilities such as design for machining and assembly (DFMA), team approach and computer aided engineering being used for a most cost-effective custom molding solution. These techniques should be part of standard design procedure for conversion programs to cope with the challenges of today and tomorrow. (orig./HW)

Vent hood concept for safely unloading TRUPACT-IIs

International Nuclear Information System (INIS)

Kelley, C.R.

1991-01-01

Receipt of transuranic (TRU) waste in the TRUPACT-2 shipping package, implies a potential of receiving waste packages contaminated with only alpha emitters or emitting hazardous gases. Due to the difficulty of rapidly detecting low-level alpha contamination, a strict contamination control system has been developed to check incoming waste packages in a controlled environment. A part of this control is the use of a vent hood system for the TRUPACT-2 shipping container unloading process. A clear final shroud with a monitored/filtered exhaust system has been designed and fabricated to permit direct surveillance of TRU waste packages prior to exposing personnel or facilities to possible radioactive contamination or hazardous gases. This concept has also been adapted to similar evolutions in which packages are exposed that hold TRU or hazardous materials but cannot be directly monitored prior to opening

The Manifesto for Extension and Engagement: A Perspective on Family and Consumer Sciences for the Future

Science.gov (United States)

Carroll, Jan B.; Chamberlin, Barbara; Devall, Esther; Dinstel, Roxie; Hauser-Lindstrom, Doreen; Petty, Barbara D.

2017-01-01

Extension professionals in the Western Region proclaimed The Timberline Manifesto at their 100-year celebration, "Centennial on the Summit," at Mount Hood, OR, in 2014. Family and consumer sciences (FCS) leaders relate this platform to the future of FCS: our opportunities for success in engagement, integration, technology, demand-driven…

Pre-migratory congregations of Red-crowned (Grus japonensis, White-naped (G. vipio and Hooded (G. monacha cranes in the Muraviovka Park for Sustainable Land Use in 1992

Directory of Open Access Journals (Sweden)

P. I. Gorlov

2017-05-01

Full Text Available The autumn pre-migratory concentrations of Red-crowned, White-naped and Hooded Cranes were studied in the Muraviovka Park for Sustainable Land Use and Environmentla Education (Tambov District, Amur Region, Russian Federation during 23.08–29.09.1992. We counted 292 Hooded Cranes, 34 White-naped Cranes, and 17 Red-crowned Cranes during the study period. We also marked specific differences in the behaviour of the birds connected with their readiness for migration. The Hooded Cranes showed the greatest readiness for migration. We observed mutual flights, overnight stays, and feeding of adult birds and family groups in their flocks. This was not the same in the flocks of White-naped Cranes. However, the average number of birds in the flocks of White-naped Cranes had increased by the end of our observations due to new families joining the general flock. The family parties of the Red-crowned Crane and adult birds without young individuals stayed apart from each other and from other crane species during the whole observation period. We registered the autumn departure of Hooded Cranes in late September, the migratory departure of White-naped Cranes in the middle of October, and the Red-crowned Cranes left the area in the first half of November. The breeding period for all crane species starts at the same time: the third decade of April – the beginning of May. The young of the studied crane species differ significantly in the period of time before fledging: Hooded Cranes – 55–60 days, White-naped Cranes – 65–70 days, and Red-crowned Cranes – 70–75 days because of their specific differences in the ratio of size to weight (1 : 1.3 : 1.7. Thus, the time difference between the Hooded and Red-crowned Cranes is about 2–3 weeks. We suggest that this is the main reason that determines the differences between these species in the timing of the the start of autumn migration.

SPECIFIC FEATURES OF TECHNOLOGY OF MANUFACTURING A ZINC-COATED TUB WIRE FOR MUZZLE (BOTTLE’ HOOD WIRE

Directory of Open Access Journals (Sweden)

D. B. Zuev

2016-01-01

Full Text Available The paper presents the main technical specifications of galvanized low carbon wire for muzzles (bottle’hood wire, consistent with the exploitation requirements to the wire in the manufacture and use of muzzles. The main criteria when selecting the steel grade and upon selection of the technological processes are given. 

Estimates of Nutrient Loading by Ground-Water Discharge into the Lynch Cove Area of Hood Canal, Washington

Science.gov (United States)

Simonds, F. William; Swarzenski, Peter W.; Rosenberry, Donald O.; Reich, Christopher D.; Paulson, Anthony J.

2008-01-01

Low dissolved oxygen concentrations in the waters of Hood Canal threaten marine life in late summer and early autumn. Oxygen depletion in the deep layers and landward reaches of the canal is caused by decomposition of excess phytoplankton biomass, which feeds on nutrients (primarily nitrogen compounds) that enter the canal from various sources, along with stratification of the water column that prevents mixing and replenishment of oxygen. Although seawater entering the canal is the largest source of nitrogen, ground-water discharge to the canal also contributes significant quantities, particularly during summer months when phytoplankton growth is most sensitive to nutrient availability. Quantifying ground-water derived nutrient loads entering an ecologically sensitive system such as Hood Canal is a critical component of constraining the total nutrient budget and ultimately implementing effective management strategies to reduce impacts of eutrophication. The amount of nutrients entering Hood Canal from ground water was estimated using traditional and indirect measurements of ground-water discharge, and analysis of nutrient concentrations. Ground-water discharge to Hood Canal is variable in space and time because of local geology, variable hydraulic gradients in the ground-water system adjacent to the shoreline, and a large tidal range of 3 to 5 meters. Intensive studies of ground-water seepage and hydraulic-head gradients in the shallow, nearshore areas were used to quantify the freshwater component of submarine ground-water discharge (SGD), whereas indirect methods using radon and radium geochemical tracers helped quantify total SGD and recirculated seawater. In areas with confirmed ground-water discharge, shore-perpendicular electrical resistivity profiles, continuous electromagnetic seepage-meter measurements, and continuous radon measurements were used to visualize temporal variations in ground-water discharge over several tidal cycles. The results of these

The politics of particularism: HBCUs, Spelman College, and the struggle to educate Black women in science, 1950--1997

Science.gov (United States)

Scriven, Olivia A.

Since the close of World War II, higher education has been central to the growth of U.S. science, but the role of historically Black colleges and universities (HBCUs) has been under-explored within this narrative. The nation's 105 HBCUs constitute less than one percent of the U.S. higher education community, but consistently have served as a major conduit for the production of African Americans in the sciences, technology, mathematics and engineering. National Science Foundation data reflect an average 29 percent share for the period 1994-2001. The output is even more striking when examined by degrees awarded in disciplinary clusters---50 percent in the agricultural sciences, 45 percent in the physical sciences and mathematics, and 42 percent in the biological sciences. This research explores the role of HBCUs in educating African Americans in science from the boosterism period shortly following World War II, through affirmative action legislation of the 1960s and 1970s, and concluding with current federal policies. A particular analysis is undertaken of Spelman College, a private liberal arts college founded by New England missionaries in the South during the late 19th century as a seminary for former slave women and girls. Spelman presents a unique case to analyze the particularistic characteristics of race, gender and institutional setting within the context of a so-called normative structure of science. Over a 25-year period, Spelman was able to rise beyond the structural limitations of its position as a Black college, a women's college, and a southern college to become one of the single most productive undergraduate institution for African American women earning the baccalaureate degree in science. What new perspectives might the Spelman story specifically and the history of HBCUs generally offer about the history of U.S. science, the notion that careers be open to talent, and current public policy discourse regarding efforts to increase the participation of

"Hold up..do pigs eat bacon?!" An investigation of science instruction for urban Black youth and the need for a culturally considerate response

Science.gov (United States)

Ridgeway, Monica Lynn

As a critical race ethnography, this dissertation attempts to foreground the richness of Black urban youth culture during and around science classroom instruction. Ironically, during an era of much diversity rhetoric in the United States, the culture of urban Black youth is rarely reflected in mainstream public school culture. I attempt to explicate such a worldview compassionately and authentically for both insiders and outsiders of the lived experiences of Black America. Education in the United States can be damning for Black youth who do not fit the mainstream mold, and several authors have provided detailed critique of mechanisms that shape, direct, and marginalize outliers to the successful academic cultural model. The U.S. through this lens is experiencing an opportunity gap, not an achievement gap--one which equitable educational experience can best be viewed through the richness of critical ethnographic methods. This methodical approach allowed me as a researcher to listen to marginalized voices and to incorporate lived interactions with youth, their parents, and community stakeholders all committed to provide support for the today's youth. As a Black female science educator, I explore the evidence for reform impact as I examine in school experiences and science teaching of culturally relevant pedagogies for urban, working-class and poor families of color in grades six-eight who participated in a Western New York academic enrichment program. Findings suggest that skepticism of reform efforts and new pedagogical approaches existed for all stakeholders aforementioned, but that students were the most amenable and responsive to alternative educational approaches. Specific recommendations for engaging students in inquiry processes are given for teachers, institutions, parents and students on the basis of videotaped lessons, interviews, and instructional artifacts. Implications include the recommendations that educators working with youth of color need to be

Harvest-related edge effects on prey availability and foraging of hooded warblers in a bottomland hardwood forest

Science.gov (United States)

John C. Kilgo

2005-01-01

The effects of harvest-created canopy gaps in bottomland hardwood forests on arthropod abundance and, hence, the foraging ecology of birds are poorly understood. I predicted that arthropod abundance would be high near edges of group-selection harvest gaps and lower in the surrounding forest, and that male Hooded Warblers (Wilsonia citrina) foraging...

Hood of the truck statistics for food animal practitioners.

Science.gov (United States)

Slenning, Barrett D

2006-03-01

This article offers some tips on working with statistics and develops four relatively simple procedures to deal with most kinds of data with which veterinarians work. The criterion for a procedure to be a "Hood of the Truck Statistics" (HOT Stats) technique is that it must be simple enough to be done with pencil, paper, and a calculator. The goal of HOT Stats is to have the tools available to run quick analyses in only a few minutes so that decisions can be made in a timely fashion. The discipline allows us to move away from the all-too-common guess work about effects and differences we perceive following a change in treatment or management. The techniques allow us to move toward making more defensible, credible, and more quantifiably "risk-aware" real-time recommendations to our clients.

W. E. B. Du Bois at the center: from science, civil rights movement, to Black Lives Matter.

Science.gov (United States)

Morris, Aldon

2017-03-01

I am honoured to present the 2016 British Journal of Sociology Annual Lecture at the London School of Economics. My lecture is based on ideas derived from my new book, The Scholar Denied: W.E.B. Du Bois and the Birth of Modern Sociology. In this essay I make three arguments. First, W.E.B. Du Bois and his Atlanta School of Sociology pioneered scientific sociology in the United States. Second, Du Bois pioneered a public sociology that creatively combined sociology and activism. Finally, Du Bois pioneered a politically engaged social science relevant for contemporary political struggles including the contemporary Black Lives Matter movement. © London School of Economics and Political Science 2017.

Black smokers and the Tree of Life

Science.gov (United States)

Linich, Michael

The molecular biology revolution has turned the classification of life on its head. Is Whittaker's five-kingdom scheme for the classification of living things no longer relevant to life science education? Coupled with this is the discovery that most microscopic life cannot yet be brought into culture. One of the key organisms making this knowledge possible is Methanococcus jannishi a microorganism found in black smokers. This workshop presents the development of the Universal Tree of Life in a historical context and then links together major concepts in the New South Wales senior science programs of Earth and Environmental Science and Biology by examining the biological and geological aspects of changes to black smokers over geological time.

Black Scientists and Inventors in the United States: 1731-1980. Curriculum Guide: Department of Science, Cambridge Rindge and Latin School.

Science.gov (United States)

Walcott, Phyllis B.

Four units focusing on 16 different Black scientists or inventors who have contributed to American life and research are presented. As part of an interdisciplinary high school science course, the units are designed to help students develop an understanding of and appreciation for the talents of the individuals studied, motivate minority students…

The Black Hole in Science Ranks.

Science.gov (United States)

Rasekoala, Elizabeth

This paper reviews four decades of research on race and education in Great Britain and discusses the deficit theories of underachievement that serve as the structure of most of the studies. Focus is placed on black youth of Caribbean origin and how they perform in British schools. Consideration is also given to constructive frameworks from gender…

From X-ray binaries to quasars black holes on all mass scales black holes on all mass scales

CERN Document Server

Ho, L C; Maccarone, T J

2005-01-01

This volume brings together contributions from many of the world's leading authorities on black hole accretion. The papers within represent part of a new movement to make use of the relative advantages of studying stellar mass and supermassive black holes and to bring together the knowledge gained from the two approaches. The topics discussed here run the gamut of the state of the art in black hole observational and theoretical work-variability, spectroscopy, disk-jet connections, and multi-wavelength campaigns on black holes are all covered. Reprinted from ASTROPHYSICS AND SPACE SCIENCE, 300:1-3 (2005)

Nocturnal feeding under artificial light conditions by Brown-hooded Gull (Larus maculipennis) in Puerto Madryn harbour (Chubut Province, Argentina)

NARCIS (Netherlands)

Leopold, M.F.; Philippart, C.J.M.; Yorio, P.

2010-01-01

This paper describes nocturnal, marine feeding behaviour in the Brown-hooded Gull (Larus maculipennis) in November 2009. The gulls assembled at night at the end of a long pier, running 800 m offshore into the Golfo Nuevo, at Puerto Madryn, Chubut Province, Argentina. Powerful lights predictably

Research Sources and Microforms in Black Studies: An Annotated Bibliography.

Science.gov (United States)

Ridinger, Robert B. Marks

1985-01-01

Analyzes 93 reference works and 23 microform collections concerning the Black American experience in 13 subject areas of the social sciences (anthropology, biography, race relations and civil rights, the Black church, communication studies, economics, education, dance, genealogy, Black history, sports, women's studies, and literature and language)…

Utilisation of polyurethane composit with 50% composition of roystonea regia fiber as noise reduction panel on car hood

Science.gov (United States)

Ikhwansyah; Mulia; Gunawan, S.; Lubis, R. D. W.

2018-02-01

The objective is to get the characteristics of noise reduction, noise reduction level, variety of measurement spaces, and knowing the process in making acoustic material of natural fiber becomes noise reduction on a car hood. The process of making noise reduction material used casting method and pressed by using molded press. The composition of noise reduction material consist of 50% roystonea regia by 32 mesh and 50% combined by gypsum and polyurethane. The result shows that the average result of noise reduction at X1- side is 5,7% and X2- side is 3,9%, X1+ side is 0,9% and X2+ side is 6,2%, Z1- side is 8,9% and Z2- side is 10,1%, Z1+ side is 9,7% and Z2+ side is 10,01%. The main conclusion of the study shows that a noise reduction which made of roystonea regia with 32 mesh mixed by matrix of polyurethane and gypsum is appropriate for noise reduction on car hood.

The Robin Hood method - A novel numerical method for electrostatic problems based on a non-local charge transfer

International Nuclear Information System (INIS)

Lazic, Predrag; Stefancic, Hrvoje; Abraham, Hrvoje

2006-01-01

We introduce a novel numerical method, named the Robin Hood method, of solving electrostatic problems. The approach of the method is closest to the boundary element methods, although significant conceptual differences exist with respect to this class of methods. The method achieves equipotentiality of conducting surfaces by iterative non-local charge transfer. For each of the conducting surfaces, non-local charge transfers are performed between surface elements, which differ the most from the targeted equipotentiality of the surface. The method is tested against analytical solutions and its wide range of application is demonstrated. The method has appealing technical characteristics. For the problem with N surface elements, the computational complexity of the method essentially scales with N α , where α < 2, the required computer memory scales with N, while the error of the potential decreases exponentially with the number of iterations for many orders of magnitude of the error, without the presence of the Critical Slowing Down. The Robin Hood method could prove useful in other classical or even quantum problems. Some future development ideas for possible applications outside electrostatics are addressed

Materials Science | NREL

Science.gov (United States)

microscopy and imaging science, interfacial and surface science, materials discovery, and thin-film material Science Materials Science Illustration with bottom row showing a ball-and-stick model and top row dense black band. State-of-the-art advances in materials science come from a combination of experiments

História da química e da geologia: Joseph Black e James Hutton como referências para educação em ciências History of chemistry and geology: Joseph Black and James Hutton as references for science education

Directory of Open Access Journals (Sweden)

Natalina Aparecida L. Sicca

2002-07-01

Full Text Available The second half of eighteenth century is marked by the advancement of chemistry and geology. The first science acquired the law of conservation of mass and this science represented a important support to geology and mineralogy. We say that both became modern science that time. Our aim is to show up some interrelations between history of chemistry and history of geology by means of the study of Joseph Black's and James Hutton's works. We defend that it is positive to science education to understand and approach the relations among different and disciplinary areas of science.

Measuring spin of black holes in the universe

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Measuring spin of black holes in the universe. Department of Physics Indian Institute of Science Bangalore. Notes: 74th Annual Meeting of Indian Academy of Science.

Pathfinders on Black Dance in America.

Science.gov (United States)

Roy, Loriene, Ed.

This is a compilation of 18 pathfinders (i.e., a bibliographic instruction aid) on black dance in America, prepared by graduate students in the "Information Resources in the Humanities" and the "Information Resources in the Social Sciences" classes in the Graduate School of Library and Information Science at the University of…

The Milky Way's Supermassive Black Hole: How Good a Case Is It? A Challenge for Astrophysics & Philosophy of Science

Czech Academy of Sciences Publication Activity Database

Eckart, A.; Kiefer, C.; Britzen, S.; Zajaček, M.; Laemmerzahl, C.; Stoeckler, M.; Valencia-S, M.; Karas, Vladimír; García-Marín, M.

2017-01-01

Roč. 47, č. 5 (2017), s. 553-624 ISSN 0015-9018 R&D Projects: GA MŠk(CZ) 7E13012; GA ČR GB14-37086G EU Projects: European Commission(XE) 312789 - STRONGGRAVITY Institutional support: RVO:67985815 Keywords : black holes * mass * spin Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 1.067, year: 2016

Addendum 4 to CSAR 81-001, Installation of an Official Critical Drain on the Plexiglass Contamination Barrier in HC-227T Hood

International Nuclear Information System (INIS)

Chiao, T.

1995-12-01

This report defines the maximum space allowed between the floor surface and the lower edge of an official criticality drain which is to be installed on the plexiglas contamination barrier in HC-227T Hood

The Pride and the Passion: Introduction to Black History.

Science.gov (United States)

Berry, Goodman

1983-01-01

The first Blacks in the Americas arrived before the Pilgrims landed at Plymouth Rock. Blacks have contributed to the development of the United States in the fields of government, education, science, music, entertainment (comedy and drama), literature, art, and athletics. (AOS)

Computer-games for gravitational wave science outreach: Black Hole Pong and Space Time Quest

International Nuclear Information System (INIS)

Carbone, L; Bond, C; Brown, D; Brückner, F; Grover, K; Lodhia, D; Mingarelli, C M F; Fulda, P; Smith, R J E; Unwin, R; Vecchio, A; Wang, M; Whalley, L; Freise, A

2012-01-01

We have established a program aimed at developing computer applications and web applets to be used for educational purposes as well as gravitational wave outreach activities. These applications and applets teach gravitational wave physics and technology. The computer programs are generated in collaboration with undergraduates and summer students as part of our teaching activities, and are freely distributed on a dedicated website. As part of this program, we have developed two computer-games related to gravitational wave science: 'Black Hole Pong' and 'Space Time Quest'. In this article we present an overview of our computer related outreach activities and discuss the games and their educational aspects, and report on some positive feedback received.

Identification of a Major Locus Contributing to Erythrocyte 2,3-Diphosphoglycerate Variability in Hooded (Long-Evans) Rats

Science.gov (United States)

Noble, N. A.; Brewer, G. J.

1977-01-01

The erythrocyte glycolytic intermediate 2,3-diphosphoglycerate (DPG) and adenosine triphosphate (ATP) play an important role in oxygen transport and delivery by binding to hemoglobin (Hb) and reducing its affinity for oxygen. Considerable quantitative variability in the levels of DPG and ATP exists in human populations and in a population of hooded (Long-Evans) rats we have studied. This paper presents the results of studies on the genetic component of DPG-level variation in an outbred population of hooded rats. Beginning with about 100 rats, a two-way selection experiment was initiated. Pairs of rats with the highest DPG levels were mated to produce a High-DPG rat strain and animals with the lowest DPG levels were mated to produce a Low-DPG strain. Mean DPG levels responded rapidly to selection and, from generation 3 on, the differences between strain means were highly significant. Ten High-DPG strain rats were intercrossed with 10 Low-DPG strain rats of generation 10 to produce an F1 generation in which the DPG levels were almost as high as those of High-DPG animals. This indicates partial dominance of High-DPG alleles. The F2 DPG-level distribution showed two distinct subpopulations. The high DPG subpopulation contained three times as many animals as the low DPG subpopulation. From these results and the statistical analyses performed, it was concluded that the DPG differences between strains were due to an allelic difference at one major locus, the allele carried by the High-DPG strain showing partial dominance over the allele carried by the Low-DPG strain. It appears that this locus may also effect ATP levels to a large extent and is polymorphic in hooded rat populations. Identification of this locus gives us a useful tool for studies of the physiological effects of DPG variability, as well as providing an example of a major gene effect in a quantitatively varying trait. PMID:863239

efficient screening procedure for black sigatoka disease of banana

African Journals Online (AJOL)

ACSS

3 University of Copenhagen, Faculty of Science, Department of Plant and Environmental Sciences, ... procedure for black sigatoka disease in order to provide a reliable controlled environment ..... Inoculation of emerging leaves, on average.

Understanding the fate of merging supermassive black holes

International Nuclear Information System (INIS)

Campanelli, Manuela

2005-01-01

Understanding the fate of merging supermassive black holes in galactic mergers, and the gravitational wave emission from this process, are important LISA science goals. To this end, we present results from numerical relativity simulations of binary black hole mergers using the so-called Lazarus approach to model gravitational radiation from these events. In particular, we focus here on some recent calculations of the final spin and recoil velocity of the remnant hole formed at the end of a binary black hole merger process, which may constrain the growth history of massive black holes at the core of galaxies and globular clusters

Reconceptualizing successful aging among black women and the relevance of the strong black woman archetype.

Science.gov (United States)

Baker, Tamara A; Buchanan, NiCole T; Mingo, Chivon A; Roker, Rosalyn; Brown, Candace S

2015-02-01

Although there are multiple pathways to successful aging, little is known of what it means to age successfully among black women. There is a growing body of literature suggesting that black women experience a number of social challenges (sexism and racism) that may present as barriers to aging successfully. Applying aspects of the Strong Black Women ideal, into theoretical concepts of successful aging, may be particularly relevant in understanding which factors impair or promote the ability of black women to age successfully. The Strong Black Women archetype is a culturally salient ideal prescribing that black women render a guise of self-reliance, selflessness, and psychological, emotional, and physical strength. Although this ideal has received considerable attention in the behavioral sciences, it has been largely absent within the gerontology field. Nevertheless, understanding the dynamics of this cultural ideal may enhance our knowledge while developing an appreciation of the black woman's ability to age successfully. Rather than summarize the social, physical, and mental health literature focusing on health outcomes of black women, this conceptual review examines the Strong Black Women archetype and its application to the lived experiences of black women and contributions to current theories of successful aging. Focusing on successful aging exclusively among black women enhances our understanding of this group by considering their identity as women of color while recognizing factors that dictate their ability to age successfully. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

76 FR 42502 - Substantial Product Hazard List: Children's Upper Outerwear in Sizes 2T to 12 With Neck or Hood...

Science.gov (United States)

2011-07-19

... because children of those ages are most at risk. 4. Adult Apparel and Marketing Concerns (Comment 4)--Two... smaller adult sizes and larger children's sizes. Further, children at the pre-teen and teen stages often... channel, and the commenters raised concerns about the 2009 recall of children's hooded sweatshirts with...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. Wilaiwan Chanmanee. Articles written in Journal of Chemical Sciences. Volume 121 Issue 5 September 2009 pp 655-664. Platinum-carbon black-titanium dioxide nanocomposite electrocatalysts for fuel cell applications · Satheesh Sambandam Vinodh Valluri Wilaiwan ...

Microbiological and serological monitoring in hooded crow (Corvus corone cornix in the Region Lombardia, Italy

Directory of Open Access Journals (Sweden)

Guido Grilli

2010-01-01

Full Text Available The health status of 276 hooded crows (Corvus corone cornix from various provinces of Lombardy was monitored for three years. Bacteriological examination detected E. coli (76%, Campylobacter jejuni (17%, Salmonella typhimurium (11.6%, Yersinia spp. (6.5%, Clamydophila abortus and C. psittaci (2.6%; from six birds showing severe prostration Pasteurella multocida was isolated. Virological and serological tests were negative for Avian Influenza virus (AIV, West Nile virus (WNV and only three samples were positive for Newcastle disease virus (NDV but only at serology (titre 1:16.

The Award Winning Black Suns

Science.gov (United States)

Holbrook, Jarita

2018-01-01

Black Suns: An Astrophysics Adventure is a documentary film focusing on the annular and total solar eclipses of 2012. We made a different kind of astronomy documentary showing the human aspects rather than just focusing on pretty astronomy pictures. The film combines personal stories with science. Our heroes are Hakeem Oluseyi and Alphonse Sterling, who valiantly travel to study the solar corona during total solar eclipses. The goals of the film included presenting three dimensional scientists, to show their paths to becoming astrophysicists, and to show them as they collect data and work as scientists. Drama and tension surround taking data during the small window of time during totality. The Black Suns was filmed in Tokyo, Cairns, Tucson, and Melbourne Florida. Uniquely, the film began through a Kickstarter campaign to fund travel and filming in Tokyo. Many American Astronomical Society members donated to the film! Black Suns won the Jury Prize at the 2017 Art of Brooklyn Film Festival. Black Suns will be screening in full on ???.

Do beliefs about science limit access to the science discourse ...

African Journals Online (AJOL)

While the shortage of black South Africans who are qualified in the sciences and applied sciences is severe, political changes have already begun to provide fairer access to tertiary study in these fields. Examining the role of subtler and more widely spread societal attitudes that limit access to the science discourse ...

"Iron-Clad" Evidence For Spinning Black Hole

Science.gov (United States)

2003-09-01

-energy particles have been detected around both types of black holes. Why do some stellar black holes spin rapidly and others not? One possibility is that differences in spin are imparted at birth when a massive star collapses. Another possibility is that the spin rate depends on how long the black hole has been devouring matter from its companion star, a process that makes the black hole spin faster. Black holes with more rapid spin, XTE J1650-500 and GX 339-4, have low-mass companion stars. These relatively long-lived stars may have been feeding the black hole for longer, allowing it to spin up to faster rates. Cygnus X-1 with its short-lived companion star may not have not time to spin up. Miller is a National Science Foundation Astronomy & Astrophysics Postdoctoral Fellow. His primary collaborators in this work were Walter Lewin if the Massachusetts Institute of Technology in Cambridge, Andrew Fabian of the University of Cambridge, UK, and Chris Reynolds of the University of Maryland, College Park. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the Office of Space Science, NASA Headquarters, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW, Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

External Labor Markets and the Distribution of Black Scientists and Engineers in Academia.

Science.gov (United States)

Kulis, Stephen; Shaw, Heather; Chong, Yinong

2000-01-01

Analyzes data from the 1989 Survey of Doctorate Recipients to evaluate racial segmentation of the academic labor market along geographic and disciplinary lines. Finds that black faculty in the sciences and engineering are found disproportionately in southern, historically black institutions; areas with sizable black populations; and, independent…

Data from moored current meters, temperature and salinity from a historical mooring placed in Hood Canal, Puget Sound, February - April 1980 (NODC Accession 0000680)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Physical, current, and other data were collected from moored buoys in Hood Canal and the Puget Sound from 08 February 1980 to 10 April 1980. Data were collected by...

Being beyond: The Black Legend and how we got over it.

Science.gov (United States)

Slater, John; López-Terrada, Maríaluz

2017-06-01

We used to think it was the job of a historian of Spanish science to combat the negative evaluations of Hispanic cultures that came to be known as the Black Legend. Paradoxically, attempts to amend dominant narratives of the history of science (such as the Scientific Revolution) so that they might accommodate Spain bolstered the very stories we meant to dismantle. Caring about the Black Legend deformed the history we were trying to write and never convinced the people we hoped to sway. In this article, we provide an overview of the historiographic tendencies that most shaped our careers - responses to the Black Legend, such as contributionist history and bibliometrics - and explain why we have chosen to move on.

Black to Black

DEFF Research Database (Denmark)

Langkjær, Michael Alexander

2012-01-01

Pop musicians performing in black stage costume take advantage of cultural traditions relating to matters black. Stylistically, black is a paradoxical color: although a symbol of melancholy, pessimism, and renunciation, black also expresses minimalist modernity and signifies exclusivity (as is hi...

Environmental Assessment for Ongoing and Future Operations at U.S. Navy Dabob Bay and Hood Canal Military Operating Areas

Science.gov (United States)

2002-05-01

well as being cultivated in aquaculture operations in Puget Sound, including Hood Canal and Dabob Bay (Figure 3.4-2). Pacific oysters (Crassostrea...gigas) are widely cultivated in aquaculture operations in Puget Sound. Commercial oyster beds exist in Dabob Bay, mostly at the north end. Dabob Bay... Ecotoxicology of metals in aquatic sediments: binding and release, bioavailability, risk assessment, and remediation. Canadian Journal of

Chandra Data Reveal Rapidly Whirling Black Holes

Science.gov (United States)

2008-01-01

black holes," said co-investigator Richard Bower of Durham University. "This might help us explain the source of these incredible jets that we see stretching for enormous distances across space." One significant connection consequence of powerful, black-hole jets in galaxies in the centers of galaxy clusters is that they can pump enormous amounts of energy into their environments, and heat the gas around them. This heating prevents the gas from cooling, and affects the rate at which new stars form, thereby limiting the size of the central galaxy. Understanding the details of this fundamental feedback loop between supermassive black holes and the formation of the most massive galaxies remains an important goal in astrophysics. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

How bees distinguish black from white

Directory of Open Access Journals (Sweden)

Horridge A

2014-10-01

Full Text Available Adrian Horridge Biological Sciences, Australian National University, Canberra, ACT, AustraliaAbstract: Bee eyes have photoreceptors for ultraviolet, green, and blue wavelengths that are excited by reflected white but not by black. With ultraviolet reflections excluded by the apparatus, bees can learn to distinguish between black, gray, and white, but theories of color vision are clearly of no help in explaining how they succeed. Human vision sidesteps the issue by constructing black and white in the brain. Bees have quite different and accessible mechanisms. As revealed by extensive tests of trained bees, bees learned two strong signals displayed on either target. The first input was the position and a measure of the green receptor modulation at the vertical edges of a black area, which included a measure of the angular width between the edges of black. They also learned the average position and total amount of blue reflected from white areas. These two inputs were sufficient to help decide which of two targets held the reward of sugar solution, but the bees cared nothing for the black or white as colors, or the direction of contrast at black/white edges. These findings provide a small step toward understanding, modeling, and implementing in silicon the anti-intuitive visual system of the honeybee, in feeding behavior. Keywords: vision, detectors, black/white, color, visual processing

Vigilance and activity time-budget adjustments of wintering hooded cranes, Grus monacha, in human-dominated foraging habitats.

Science.gov (United States)

Li, Chunlin; Zhou, Lizhi; Xu, Li; Zhao, Niannian; Beauchamp, Guy

2015-01-01

Due to loss and degradation of natural wetlands, waterbirds increasingly rely on surrounding human-dominated habitats to obtain food. Quantifying vigilance patterns, investigating the trade-off among various activities, and examining the underlying mechanisms will help us understand how waterbirds adapt to human-caused disturbances. During two successive winters (November-February of 2012-13 and 2013-14), we studied the hooded crane, Grus monacha, in the Shengjin Lake National Nature Reserve (NNR), China, to investigate how the species responds to human disturbances through vigilance and activity time-budget adjustments. Our results showed striking differences in the behavior of the cranes when foraging in the highly disturbed rice paddy fields found in the buffer zone compared with the degraded natural wetlands in the core area of the NNR. Time spent vigilant decreased with flock size and cranes spent more time vigilant in the human-dominated buffer zone. In the rice paddy fields, the birds were more vigilant but also fed more at the expense of locomotion and maintenance activities. Adult cranes spent more time vigilant and foraged less than juveniles. We recommend habitat recovery in natural wetlands and community co-management in the surrounding human-dominated landscape for conservation of the hooded crane and, generally, for the vast numbers of migratory waterbirds wintering in the middle and lower reaches of the Yangtze River floodplain.

Beyond the Event Horizon: Education with Black Holes

Science.gov (United States)

Silva, Sarah; Cominsky, L.; Plait, P.; SSU E/PO Group

2006-09-01

The Sonoma State University NASA Education and Public Outreach Program (SSU E/PO), in collaboration with the Denver Museum of Nature & Science (DMNS), NOVA, Thomas Lucas Productions (TLP), the National Science Foundation and E/PO groups across NASA's Astrophysics Division, is creating a series of educational and outreach products for both formal and informal educational settings. The formal (in-class) products are closely tied with the informal (museum and television) products. An NSF-funded digital planetarium show titled "Black Holes: The Other Side of Infinity" was created by DMNS and TLP and is currently showing at several venues, with more planned. Through funding from the Swift and GLAST missions, SSU has developed an accompanying educator workshop and guide to train museum personnel in the use of black hole educational materials so that they can give professional development workshops to local teachers. In addition, SSU E/PO has worked with TLP and NOVA to create a television program ("Monster of the Milky Way") will premiere in the fall of 2006 with accompanying online educational materials. The educator guide materials include activities from NASA Astrophysics missions such as GLAST, Swift, XMM-Newton, and Gravity Probe-B, as well as from the Center for Science Education at Space Sciences Laboratory and the HEASARC education programs. We are also creating an online educational resource for use by anyone who wants to find information about black holes. It will have interactive features, including a possible museum kiosk where visitors can explore black holes. All products that are developed as a part of this program include integrated evaluation and assessment. The planetarium show has already had formative evaluation and is in the process of summative evaluation. The workshops include evaluation and follow-up work with the participating educators.

Black Holes: A Selected Bibliography.

Science.gov (United States)

Fraknoi, Andrew

1991-01-01

Offers a selected bibliography pertaining to black holes with the following categories: introductory books; introductory articles; somewhat more advanced articles; readings about Einstein's general theory of relativity; books on the death of stars; articles on the death of stars; specific articles about Supernova 1987A; relevant science fiction…

ATU/Fort Hood Solar Total Energy Military Large-Scale Experiment (LSE-1): system design and support activities. Final report, November 23, 1976-November 30, 1977

Energy Technology Data Exchange (ETDEWEB)

1977-01-01

The ATU/Fort Hood Solar Total Energy System will include a concentrating solar collector field of several acres. During periods of direct insolation, a heat-transfer fluid will be circulated through the collector field and thus heated to 500 to 600/sup 0/F. Some of the fluid will be circulated through a steam generator to drive a turbine-generator set; additional fluid will be stored in insulated tanks for use when solar energy is not available. The electrical output will satisfy a portion of the electrical load at Fort Hood's 87,000 Troop Housing Complex. Heat extracted from the turbine exhaust in the form of hot water will be used for space heating, absorption air conditioning, and domestic water heating at the 87,000 Complex. Storage tanks for the hot water are also included. The systems analysis and program support activities include studies of solar availability and energy requirements at Fort Hood, investigation of interfacing LSE-1 with existing energy systems at the 87,000 Complex, and preliminary studies of environmental, health, and safety considerations. An extensive survey of available concentrating solar collectors and modifications to a computerized system simulation model for LSE-1 use are also reported. Important program support activities are military liaison and information dissemination. The engineering test program reported involved completion of the Solar Engineering Test Module (SETM) and extensive performance testing of a single module of the linear-focusing collector.

Adolescent Black Males' Drug Trafficking and Addiction: Three Theoretical Perspectives.

Science.gov (United States)

Moore, Sharon E.

1995-01-01

Explains the incidence and nature of drug trafficking and chemical dependency among adolescent black males. The paper also discusses the social science theories of Emile Durkheim, Karl Marx, and Molefi Asante to better understand the behaviors, and the consequences of those behaviors, of young black males who participate in drug trafficking. (GR)

El espejo televisivo de Claude. Estética, ciencia y ficción en Black Mirror / Claude’s Television Mirror. Aesthetic, Science and Fiction in Black Mirror

Directory of Open Access Journals (Sweden)

Laura García Pousa

2016-08-01

��«The National Anthem», «Fifteen Million Merits» and «The Entire History of You»— aims to identify the narrative value and artistic contribution of the series.Keywords: Black Mirror, science, fiction, drama, television, screens, virtual reality, future, «The National Anthem», «Fifteen Million Merits», «The Entire History of You».

A Comparative Morphometric Analysis of Three Cranial Nerves in Two Phocids: The Hooded Seal (Cystophora cristata) and the Harbor Seal (Phoca vitulina).

Science.gov (United States)

Wohlert, Dennis; Kröger, Jürgen; Witt, Martin; Schmitt, Oliver; Wree, Andreas; Czech-Damal, Nicole; Siebert, Ursula; Folkow, Lars; Hanke, Frederike D

2016-03-01

While our knowledge about the senses of pinnipeds has increased over the last decades almost nothing is known about the organization of the neuroanatomical pathways. In a first approach to this field of research, we assessed the total number of myelinated axons of three cranial nerves (CNs) in the harbor (Phoca vitulina, Pv) and hooded seal (Cystophora cristata, Cc). Axons were counted in semithin sections of the nerves embedded in Epon and stained with toluidine blue. In both species, the highest axon number was found within the optic nerve (Pv 187,000 ± 8,000 axons, Cc 481,600 ± 1,300 axons). Generally, considering absolute axon numbers, far more axons were counted within the optic and trigmenial nerve (Pv 136,700 ± 2,500 axons, Cc 179,300 ± 6,900 axons) in hooded in comparison to harbor seals. The axon counts of the vestibulocochlear nerve are nearly identical for both species (Pv 87,100 ± 8,100 axons, Cc 86,600 ± 2,700 axons). However, when comparing cell density, the cell density is almost equal for all nerves for both species except for the optic nerve in which cell density was particularly higher than in the other nerves and higher in hooded in comparison to harbor seals. We here present the first comparative analysis of three CNs in two phocid seals. While the CNs of these closely related species share some general characteristics, pronounced differences in axon numbers/densities are apparent. These differences seem to reflect differences in e.g. size, habitat, and/or functional significance of the innervated sensory systems. © 2015 Wiley Periodicals, Inc.

Gender, mathematics, reading comprehension and science reasoning as predictors of science achievement among African-American students at a historical black college or university

Science.gov (United States)

Davis, Consuella Artiemese

This study investigated predictors that influence the science achievement of African-American non-science majors in a Physical Science class. The population consisted of male and female college students enrolled in Physical Science courses at a historical black college or university (HBCU) located in the southeastern portion of the United States. A personal data information sheet was administered to 120 participants during the Fall of 2008. The personal data information sheet consisted of questions pertaining to the high school courses, students took in math, language arts and science. It also consisted of basic background information. Students also gave written consent for their midterm and final grades earned in Physical Science to be used in the study as part of the analyses. A t-Test including chi-square tests revealed that there was not a significant difference in the raw scores of African-American females and African American males on the American College Test. A significant difference was not observed between the females and males on the ACT math subtest, t (118) = -.78, p = .43; reading comprehension subtest, t (118) = -1.44, .15 or on the science reasoning subtest, t (118) = -1.46, p = .15. A significant difference was not found between the final grades of African American females and the final grades of African American males. Chi-square tests were conducted to determine goodness of fit, X2 = 6.11, df = 1, p = .191. Although the grades of females were higher than males, results were not significant. The correlation between math ACT and final grades were not significant, r = .131, N = 120, p = .155, reading comprehension ACT and final grades were not significant, r = .072, N = 120, p = .434 and science reasoning ACT and final grades were found not to be significant, r = .109, N = 120, p = .237. Being that the majority of students who participated in the study were from one state, had similar high school backgrounds, had similar majors and were similar in

Erratic Black Hole Regulates Itself

Science.gov (United States)

2009-03-01

system," said Lee. "So, we can learn a tremendous amount about black holes by just studying stellar-mass black holes like this one." It is not known what causes the jet to turn on again once the wind dies down, and this remains one of the major unsolved mysteries in astronomy. "Every major observatory, ground and space, has been used to study this black hole for the past two decades," said Neilsen. "Although we still don't have all the answers, we think our work is a step in the right direction." This was work made using Chandra's High Energy Transmission Gratings Spectrometer. These results appear in the March 26th issue of Nature. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

Statistical characteristics of breakthrough discoveries in science using the metaphor of black and white swans

Science.gov (United States)

Zeng, Carl J.; Qi, Eric P.; Li, Simon S.; Stanley, H. Eugene; Ye, Fred Y.

2017-12-01

A publication that reports a breakthrough discovery in a particular scientific field is referred to as a ;black swan;, and the most highly-cited papers previously published in the same field ;white swans;. Important scientific progress occurs when ;white swans; meet a ;black swan;, and the citation patterns of the ;white swans; change. This metaphor combines scientific discoveries and scientometric data and suggests that breakthrough scientific discoveries are either ;black swans; or ;grey-black swans;.

Carbon nanotubes applications in separation science: A review

Energy Technology Data Exchange (ETDEWEB)

Herrera-Herrera, Antonio V.; Gonzalez-Curbelo, Miguel Angel [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Quimica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez s/n, 38206 La Laguna (Tenerife) (Spain); Hernandez-Borges, Javier, E-mail: jhborges@ull.es [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Quimica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez s/n, 38206 La Laguna (Tenerife) (Spain); Rodriguez-Delgado, Miguel Angel [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Quimica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez s/n, 38206 La Laguna (Tenerife) (Spain)

2012-07-13

Highlights: Black-Right-Pointing-Pointer The use of CNTs in Separation Science in the period 2009-2011 is reviewed. Black-Right-Pointing-Pointer CNTs as stationary phases in LC, CE and GC. Black-Right-Pointing-Pointer CNTs as pseudostationary phases in EKC. Black-Right-Pointing-Pointer CNTs as sorbents in SPE and SPME. Black-Right-Pointing-Pointer Other uses of CNTs in separation science, as LDI substrates or in membranes. - Abstract: Due to the intensive and multidisciplinary research carried out during the last two decades on carbon nanotubes (CNTs), the scientific community understands nowadays much better the chemistry, structure and properties of these interesting materials. In fact, they have found their particular place in a wide number of application fields (nanotechnology, electronics, optics, medicine, etc.) among which Analytical Chemistry is becoming more and more important. The aim of this review is to provide an updated report of the most recent manuscripts (years 2009-2011) regarding the use of CNTs in Separation Science. In particular, the use of CNTs as solid-phase extraction and microextraction sorbents, as part of membranes as well as their use in chromatography and electrophoresis will be discussed and commented. Besides, although not as fully related to Separation Science as the previous techniques, the use of CNTs as laser desorption/ionization substrates has also been considered because of its importance in the field.

MeerLICHT and BlackGEM: custom-built telescopes to detect faint optical transients

Science.gov (United States)

Bloemen, Steven; Groot, Paul; Woudt, Patrick; Klein Wolt, Marc; McBride, Vanessa; Nelemans, Gijs; Körding, Elmar; Pretorius, Margaretha L.; Roelfsema, Ronald; Bettonvil, Felix; Balster, Harry; Bakker, Roy; Dolron, Peter; van Elteren, Arjen; Elswijk, Eddy; Engels, Arno; Fender, Rob; Fokker, Marc; de Haan, Menno; Hagoort, Klaas; de Hoog, Jasper; ter Horst, Rik; van der Kevie, Giel; Kozłowski, Stanisław; Kragt, Jan; Lech, Grzegorz; Le Poole, Rudolf; Lesman, Dirk; Morren, Johan; Navarro, Ramon; Paalberends, Willem-Jelle; Paterson, Kerry; Pawłaszek, Rafal; Pessemier, Wim; Raskin, Gert; Rutten, Harrie; Scheers, Bart; Schuil, Menno; Sybilski, Piotr W.

2016-07-01

We present the MeerLICHT and BlackGEM telescopes, which are wide-field optical telescopes that are currently being built to study transient phenomena, gravitational wave counterparts and variable stars. The telescopes have 65 cm primary mirrors and a 2.7 square degree field-of-view. The MeerLICHT and BlackGEM projects have different science goals, but will use identical telescopes. The first telescope, MeerLICHT, will be commissioned at Sutherland (South Africa) in the first quarter of 2017. It will co-point with MeerKAT to collect optical data commensurate with the radio observations. After careful analysis of MeerLICHT's performance, three telescopes of the same type will be commissioned in La Silla (Chile) in 2018 to form phase I of the BlackGEM array. BlackGEM aims at detecting and characterizing optical counterparts of gravitational wave events detected by Advanced LIGO and Virgo. In this contribution we present an overview of the science goals, the design and the status of the two projects.

Looking for the invisible universe - Black matter, black energy, black holes

International Nuclear Information System (INIS)

Elbaz, David

2016-01-01

As the discovery of the expansion of the universe and of black holes put the study of cosmology into question again because it now refers to invisible things such as black holes, black energy and black matter, the author proposes an other view on the universe within such a context. He first discusses these three enigmas of black matter, black energy and black holes. In a second part, he addresses, discusses and comments five illusions: the Uranian illusion (questions of the existence of an anti-world, of black matter temperature), the Mercurian illusion (quantum gravity, the string theory), the Martian illusion (a patchwork universe, the illusion of the infinite), the cosmic Maya (the John Wheeler's cup, the holographic universe), and the narcissistic illusion

Exploration of Factors Affecting Success of Undergraduate Engineering Majors at a Historically Black University

Science.gov (United States)

Igbinoba, Egheosa P.

Blacks are underrepresented amongst persons who earn college degrees in the United States and Black males attend and complete college at a lower rate than Black females (Toldson, Fry Brown, & Sutton, 2009). According to Toldson et al. (2009), this quandary may be attributed to Black males' apathy toward education in general, waning support and ideological challenges toward Pell Grants and affirmative action, cultural incompetency on the part of the 90% White, ethnic makeup of the U.S. teaching force, and the relatively high numbers of Black males who are held back in school. In spite of the dismal statistics regarding Black male academic achievement and matriculation, there are those Black males who do participate in postsecondary education. While many studies have highlighted reasons that Black males do not achieve success in attending and persisting through college, few have adopted the anti-deficit research framework suggested by Harper (2010), identifying reasons Black males do persist in higher education. Although science, technology, engineering, and mathematics careers are identified as those most imperative to the economic competitiveness of the United States, few studies have concentrated solely on engineering majors and fewer, if any, solely on Black male engineering majors at an historically Black college and university. The aim of this study was to address an apparent gap in the literature and invoke theories for recruitment, retention, and success of Black males in engineering degree programs by employing an anti-deficit achievement framework for research of students of color in science, technology, engineering, and mathematics. Data garnered from the study included insight into participants' definitions of success, precollege experiences, factors contributing to the persistence during undergraduate study, and perceptions of attending a historically Black college and university versus a primarily White institution.

From Subhuman to Human Kind: Implicit Bias, Racial Memory, and Black Males in Schools and Society

Science.gov (United States)

Brown, Anthony L.

2018-01-01

This paper argues that implicit racial bias regarding black males is a manifestation of a long trajectory of Western racial memory and anti-blackness where black males have been considered subhuman or as human kinds. The author draws from theological, scientific, and social science literature to illustrate how racial discourses have historically…

Giant Black Hole Rips Apart Star

Science.gov (United States)

2004-02-01

hole, ruling out other possible astronomical explanations. In the future, searches using Chandra, XMM-Newton and survey instruments should find many other tidal disruptions. Detailed studies with future observatories like Constellation-X should teach us about the extreme physics around supermassive black holes. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the Office of Space Science, NASA Headquarters, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW, Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. XMM-Newton is an ESA science mission managed at the European Space Research and Technology Centre (ESTEC) in the Netherlands for the Directorate of the Scientific Programme. Additional information and images are available at: http://chandra.harvard.edu and http://chandra.nasa.gov

Heaviest Stellar Black Hole Discovered in Nearby Galaxy

Science.gov (United States)

2007-10-01

have had a radius larger than the present separation between the stars, so the stars must have been brought closer while sharing a common outer atmosphere. This process typically results in a large amount of mass being lost from the system, so much that the parent star should not have been able to form a 15.7 solar-mass black hole. The black hole's progenitor must have shed gas at a rate about 10 times less than predicted by models before it exploded. If even more massive stars also lose very little material, it could explain the incredibly luminous supernova seen recently as SN 2006gy. The progenitor for SN 2006gy is thought to have been about 150 times the mass of the Sun when it exploded. Artist's Illustration of M33 X-7 Artist's Illustration of M33 X-7 "Massive stars can be much less extravagant than people think by hanging onto a lot more of their mass toward the end of their lives," said Orosz. "This can have a big effect on the black holes that these stellar time-bombs make." Coauthor Wolfgang Pietsch was also the lead author of an article in the Astrophysical Journal that used Chandra observations to report that M33 X-7 is the first black hole in a binary system observed to undergo eclipses. The eclipsing nature enables unusually accurate estimates for the mass of the black hole and its companion. "Because it's eclipsing and because it has such extreme properties, this black hole is an incredible test-bed for studying astrophysics," said Pietsch. The length of the eclipse seen by Chandra gives information about the size of the companion. The scale of the companion's motion, as inferred from the Gemini observations, gives information about the mass of the black hole and its companion. Other observed properties of the binary were used to constrain the mass estimates. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight

The Crisis in Black and Black.

Science.gov (United States)

Hutchinson, Earl Ofari

These essays explore why the historic conflict between blacks and whites in the United States has become a crisis that divides many African Americans. The changing racial dynamic is not marked by conflicts. between the black middle class and the poor, black men and women, the black intellectual elite and rappers, black politicians and the urban…

Black generation Y students' perceptions of national sport celebrity ...

African Journals Online (AJOL)

African Journal for Physical Activity and Health Sciences ... Black generation Y students' perceptions of national sport celebrity endorsers as role models ... at tertiary institutions constitute a particularly attractive target market to marketers given ...

Effect of summer heat environment on body temperature, estrous cycles and blood antioxidant levels in Japanese Black cow.

Science.gov (United States)

Sakatani, Miki; Balboula, Ahmed Z; Yamanaka, Kenichi; Takahashi, Masashi

2012-05-01

This study investigated the effect of summer heat environment on estrous cycles and blood antioxidant levels in Japanese Black cows. A total of 13 non-lactating Japanese Black cows (summer: 9, winter: 4) were examined. Body temperature was measured rectally and intravaginally using a thermometer and data logger, respectively. Estrous behavior was monitored using a radiotelemetric pedometer that recorded walking activity. Rectal temperatures were higher during summer than winter (Pstress, and also reduces signs of estrus in Japanese Black cows. © 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.

Hooded seal Cystophora cristata foraging areas in the Northeast Atlantic Ocean-Investigated using three complementary methods.

Directory of Open Access Journals (Sweden)

Jade Vacquie-Garcia

Full Text Available Identifying environmental characteristics that define the ecological niche of a species is essential to understanding how changes in physical conditions might affect its distribution and other aspects of its ecology. The present study used satellite relay data loggers (SRDLs to study habitat use by Northeast Atlantic hooded seals (N = 20; 9 adult females, 3 adult males, and 8 juveniles. Three different methods were used in combination to achieve maximum insight regarding key foraging areas for hooded seals in this region, which have decline by 85% in recent decades: 1 first passage time (FPT; 2 vertical transit rate and; 3 change in dive drift rate. Generalized additive mixed models (GAMM were applied to each method to determine whether specific habitat characteristics were associated with foraging. Separate models were run for the post-molting and the post-breeding seasons; sex and age classes were included in the GAMMs. All three methods highlighted a few common geographic areas as being important foraging zones; however, there were also some different areas identified by the different methods, which highlights the importance of using multiple indexes when analyzing tracking and diving data to study foraging behavior. Foraging occurred most commonly in relatively shallow areas with high Sea Surface Temperatures (SST, corresponding to continental shelf areas with Atlantic Water masses. All age and sex classes overlapped spatially to some extent, but the different age and sex groups showed differences in the bathymetry of their foraging areas as well as in their vertical use of the water column. When foraging, pups dove in the upper part of the water column in relatively deep areas. Adult females foraged relatively shallowly in deep water areas too, though in shallower areas than pups. Adult males foraged close to the bottom in shallower areas.

USSTRIDE program is associated with competitive Black and Latino student applicants to medical school

OpenAIRE

Campbell, Kendall M.; Berne-Anderson, Thesla; Wang, Aihua; Dormeus, Guy; Rodríguez, José E.

2014-01-01

Purpose: We compared MCAT scores, grade point averages (GPAs), and medical school acceptance rates of Black and Latino students in an outreach program called Undergraduate Science Students Together Reaching Instructional Diversity and Excellence (USSTRIDE) to non-USSTRIDE students. We hypothesized that Black and Latino participants in USSTRIDE had higher acceptance rates to medical school, higher MCAT scores, and college GPAs when compared to other Black and Latino medical school applicants f...

77 FR 38652 - Endangered Species; Receipt of Applications for Permit

Science.gov (United States)

2012-06-28

.... Species: Ring-tailed lemur (Lemur catta) Black and white ruffed lemur (Varecia variegata) Cottontop tamarin (Saguinus oedipus) Snow leopard (Uncia uncia) Amur leopard (Panthera pardus orientalis) Siberian tiger (Panthera tigris altaica) Golden parakeet (Guarouba guarouba) Hooded crane (Grus monacha) Jackass...

Black Hole Paradox Solved By NASA's Chandra

Science.gov (United States)

2006-06-01

. Using Chandra, Miller and his team provided crucial evidence for the role of magnetic forces in the black hole accretion process. The X-ray spectrum, the number of X-rays at different energies, showed that the speed and density of the wind from J1655's disk corresponded to computer simulation predictions for magnetically-driven winds. The spectral fingerprint also ruled out the two other major competing theories to winds driven by magnetic fields. "In 1973, theorists came up with the idea that magnetic fields could drive the generation of light by gas falling onto black holes," said co-author John Raymond of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "Now, over 30 years later, we finally may have convincing evidence." Evidence for Wind in the GRO J1655-40 Spectrum Evidence for Wind in the GRO J1655-40 Spectrum This deeper understanding of how black holes accrete matter also teaches astronomers about other properties of black holes, including how they grow. "Just as a doctor wants to understand the causes of an illness and not merely the symptoms, astronomers try to understand what causes phenomena they see in the Universe," said co-author Danny Steeghs also of the Harvard-Smithsonian Center for Astrophysics. "By understanding what makes material release energy as it falls onto black holes, we may also learn how matter falls onto other important objects." In addition to accretion disks around black holes, magnetic fields may play an important role in disks detected around young sun-like stars where planets are forming, as well as ultra-dense objects called neutron stars. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center, Cambridge, Mass. Additional information and images can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov

Black Undergraduate Women and Their Sense of Belonging in STEM at Predominantly White Institutions

Science.gov (United States)

Dortch, Deniece; Patel, Chirag

2017-01-01

Because little work exists on the sense of belonging focusing on just Black undergraduate women in science, technology, engineering, and math (STEM), especially at highly selective predominantly white institutions (PWIs), this study takes a phenomenological approach to understand the lived experiences of Black undergraduate women in STEM by…

"Robin Hood" of techno-Turkey or organ trafficking in the state of ethical beings.

Science.gov (United States)

Sanal, Aslihan

2004-09-01

Dr S. is a famous transplant surgeon in the Middle East. He operates "underground" on wealthy patients in different countries, from Israel to Turkey to Russia. The media refer to him as the "Organ Mafia doctor," and patients diagnosed with renal failure speak of him sardonically as "Robin Hood," acknowledging that he takes organs from the poor to give to the rich. But ethical issues of organ trafficking are not limited to marginal private clinics and "Mafia" doctors. All-living related organ transplants in Turkey involve similar ethical dilemmas: many related or nonrelated organ recipients pay their donors, and demand continues to rise. This paper explores practices in state and university hospitals and the ethical dilemmas doctors encounter to understand where and how judicial, cultural, and social categories of "human rights" and "crime" are constructed in our high-tech world.

Black Holes Have Simple Feeding Habits

Science.gov (United States)

2008-06-01

properties of these black holes should be very helpful. In addition to Chandra, three radio arrays (the Giant Meterwave Radio Telescope, the Very Large Array and the Very Long Baseline Array), two millimeter telescopes (the Plateau de Bure Interferometer and the Submillimeter Array), and Lick Observatory in the optical were used to monitor M81. These observations were made simultaneously to ensure that brightness variations because of changes in feeding rates did not confuse the results. Chandra is the only X-ray satellite able to isolate the faint X-rays of the black hole from the emission of the rest of the galaxy. This result confirms less detailed earlier work by Andrea Merloni from the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany and colleagues that suggested that the basic properties of larger black holes are similar to the smaller ones. Their study, however, was not based on simultaneous, multi-wavelength observations nor the application of a detailed physical model. These results will appear in an upcoming issue of The Astrophysical Journal. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

Confronting Color-Blind STEM Talent Development: Toward a Contextual Model for Black Student STEM Identity

Science.gov (United States)

Collins, Kristina Henry

2018-01-01

What is Black student's science, technology, engineering, and mathematics (STEM) identity? The author addresses this question through a synthesis of the literature that includes studies that explore Black student identity. Background information regarding STEM achievement and persistence followed by empirical studies that explore STEM attitudes…

The StarDate Black Hole Encyclopedia Website blackholes.stardate.org

Science.gov (United States)

Gebhardt, Karl; Benningfield, D.; Preston, S.

2013-01-01

The StarDate Black Hole Encyclopedia website was developed over the past seven years to provide an extensive but easy-to-read resource for the public and students. A Spanish-language version, Enciclopedia de agujeros negros, is also available at blackholes.radiouniverso.org. Evaluation shows that the sites are used by the public, students, and astronomy professionals, and the site is among the top references in most web searches for individual black holes. The site comprises seven major subsections: Basics, Directory, Research, History, Pop Culture, News, and Resources. The Basics section introduces black holes, explains how they are discovered and studied, and covers their basis in the theory of gravity. This section also includes a six-minute video introduction, “Black Holes: Stranger than Fiction.” The Directory section contains extensive descriptions of more than 80 well-known stellar, intermediate, and supermassive black holes as well as images and vital statistics of each. The Research section takes a look at three NSF-funded projects, including the work of Andrea Ghez, Karl Gebhardt and Jenny Greene, and the LIGO project. The History section provides a timeline of black holes from Isaac Newton to the present. Some of the best and worst roles played by black holes in films, TV shows, and books are included in the Pop Culture section (and pop culture references and images are sprinkled through the rest of the site). An archive of news reports about black holes is available in the News section, which provides links to the original stories or press releases. And the Resources section offers FAQs, articles from StarDate magazine and radio programs, activities for students that are tied to national standards, a glossary, and a reading list of books and websites. We have conducted both quantitative and qualitative evaluation on the black hole websites. This material is based upon work supported by the National Science Foundation under Grant No. 0935841. Any

Black hole physics. Black hole lightning due to particle acceleration at subhorizon scales.

Science.gov (United States)

Aleksić, J; Ansoldi, S; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; Becerra González, J; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; de Oña Wilhelmi, E; Delgado Mendez, C; Dominis Prester, D; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; García López, R J; Garczarczyk, M; Garrido Terrats, D; Gaug, M; Godinović, N; González Muñoz, A; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Prada Moroni, P G; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rodriguez Garcia, J; Rügamer, S; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Torres, D F; Toyama, T; Treves, A; Uellenbeck, M; Vogler, P; Zanin, R; Kadler, M; Schulz, R; Ros, E; Bach, U; Krauß, F; Wilms, J

2014-11-28

Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes, revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet. Copyright © 2014, American Association for the Advancement of Science.

The Challenges and Success of Implementing Climate Studies Lessons for Pre-Professional Teachers at a Small Historically Black College to Engage Student Teaching of Science Pedagogy and Content Skill Based Learning.

Science.gov (United States)

Arnold, J.; Wider-Lewis, F.; Miller-Jenkins, A.

2017-12-01

This poster is a description of the challenges and success of implementing climate studies lessons for pre-service teachers to engage student teaching pedagogy and content skill based learning. Edward Waters College is a historical black college with an elementary education teacher program focused on urban elementary school teaching and learning. Pre-Service Elementary Educator Students often have difficulty with science and mathematics content and pedagogy. This poster will highlight the barriers and successes of using climate studies lessons to develop and enhance pre-service teachers' knowledge of elementary science principles particularly related to climate studies, physical and earth space science.

Stereotype Threat Among Black and White Women in Health Care Settings

Science.gov (United States)

Abdou, Cleopatra M.; Fingerhut, Adam W.

2016-01-01

The first of its kind, the present experiment applied stereotype threat—the threat of being judged by or confirming negative group-based stereotypes—to the health sciences. Black and White women (N = 162) engaged in a virtual health care situation. In the experimental condition, one’s ethnic identity and negative stereotypes of Black women specifically were made salient. As predicted, Black women in the stereotype threat condition who were strongly identified as Black (in terms of having explored what their ethnic identity means to them and the role it plays in their lives) reported significantly greater anxiety while waiting to see the doctor in the virtual health care setting than all other women. It is hypothesized that stereotype threat experienced in health care settings is one overlooked social barrier contributing to disparities in health care utilization and broader health disparities among Black women. PMID:25045944

An overview of the 2009 Fort Hood Robotics Rodeo

Science.gov (United States)

Norberg, Seth

2010-04-01

The Robotics Rodeo held from 31 August to 3 September 2009 at Fort Hood, Texas, had three stated goals: educate key decision makers and align the robotics industry; educate Soldiers and developers; and perform a live market survey of the current state of technologies to encourage the development of robotic systems to support operational needs. Both events that comprised the Robotics Rodeo, the Extravaganza and the robotic technology observation, demonstration and discussion (RTOD2) addressed these stated goals. The Extravaganza was designed to foster interaction between the vendors and the visitors who included the media, Soldiers, others in the robotics industry and key decision makers. The RTOD2 allowed the vendors a more private and focused interaction with the subject matter experts teams, this was the forum for the vendors to demonstrate their robotic systems that supported the III Corps operational needs statements that are focused on route clearance, convoy operations, persistent stare, and robotic wingman. While the goals of the Rodeo were achieved, the underlying success from the event is the development of a new business model that is focused on collapsing the current model to get technologies into the hands of our warfighters quicker. This new model takes the real time data collection from the Rodeo, the Warfighter Needs from TRADOC, the emerging requirements from our current engagements, and assistance from industry partners to develop a future Army strategy for the rapid fielding of unmanned systems technologies.

Chandra Sees Remarkable Eclipse of Black Hole

Science.gov (United States)

2007-04-01

Chandra X-ray Image of NGC 1365 "Thanks to this eclipse, we were able to probe much closer to the edge of this black hole than anyone has been able to before," said co-author Martin Elvis from CfA. "Material this close in will likely cross the event horizon and disappear from the universe in about a hundred years, a blink of an eye in cosmic terms." In addition to measuring the size of this disk of material, Risaliti and his colleagues were also able to estimate the location of the dense gas cloud that eclipsed the X-ray source and central black hole. The Chandra data show that this cloud is one hundredth of a light year from the black hole's event horizon, or 300 times closer than generally thought. "AGN include the brightest objects in the Universe and are powerful probes of the early universe. So, it's vital to understand their basic structure," said Risaliti. "It turns out that we still have work to do to understand these monsters." A series of six Chandra observations of NGC 1365 were made every two days over a period of two weeks in April 2006. During five of the observations, high energy X-rays from the central X-ray source were visible, but in the second one - corresponding to the eclipse - they were not. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center, Cambridge, Mass. Additional information and images are available at: http://chandra.harvard.edu and http://chandra.nasa.gov

Stratigraphy, sedimentology and bulk organic geochemistry of black ...

Indian Academy of Sciences (India)

Stratigraphy, sedimentology and bulk organic geochemistry of black shales from the Proterozoic. Vindhyan Supergroup (central India). S Banerjee1,∗. , S Dutta. 2. , S Paikaray. 1 and U Mann. 2. 1. Department of Earth Sciences, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India. 2. Forschungszentrum ...

Multiple [3H]imipramine binding sites in brains of male and female Fawn-Hooded and Long-Evans rats

International Nuclear Information System (INIS)

Ieni, J.R.; Zukin, S.R.; Praag, H.M. van; Tobach, E.; Barr, G.A.

1985-01-01

Comparisons of high- and low-affinity [ 3 H]imipramine binding to whole brain homogenates from adult male and female rats of the Fawn-Hooded and Long-Evans strains were performed. Most strikingly, no significant differences were observed between the two strains in any of the binding parameters, indicating that brain [ 3 H]imipramine binding sites, which may be related to the serotonergic uptake process, appear normal in a strain of rats with serotonin platelet storage pool disease. However, a significant sex difference in high- but not low-affinity whole brain [ 3 H]imipramine Bsub(max) values was observed, with females of both strains having higher densities than males. (Auth.)

Unveiling the edge of time black holes, white holes, wormholes

CERN Document Server

Gribbin, John

1992-01-01

Acclaimed science writer John Gribbin recounts dramatic stories that have led scientists to believe black holes and their more mysterious kin are not only real, but might actually provide a passage to other universes and travel through time.

Black Silicon Solar Cells with Black Ribbons

DEFF Research Database (Denmark)

Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

2016-01-01

We present the combination of mask-less reactive ion etch (RIE) texturing and blackened interconnecting ribbons as a method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon made by mask-less reactive ion etching has total, average...... in the range 15.7-16.3%. The KOH-textured reference cell had an efficiency of 17.9%. The combination of black Si and black interconnecting ribbons may result in aesthetic, all-black panels based on conventional, front-contacted silicon solar cells....... reflectance below 0.5% across a 156x156 mm2 silicon (Si) wafer. Black interconnecting ribbons were realized by oxidizing copper resulting in reflectance below 3% in the visible wavelength range. Screen-printed Si solar cells were realized on 156x156 mm2 black Si substrates with resulting efficiencies...

75 FR 81793 - Endangered and Threatened Wildlife and Plants; Listing Seven Brazilian Bird Species as Endangered...

Science.gov (United States)

2010-12-28

... northeastern Argentina (Morellato and Haddad 2000, pp. 786-787; Conservation International 2007a, p. 1; H[ouml... and Life History The black-hooded antwren inhabits lush understories of remnant old- growth and early... and Life History The Brazilian merganser is highly adapted to mountainous, highly oxygenated clear...

Black Hole Results from XMM-Newton

Directory of Open Access Journals (Sweden)

Norbert Schartel

2014-12-01

Full Text Available XMM-Newton is one of the most successful science missions of the  European Space Agency. Since 2003 every year about 300 articles are published in refereed journals making directly use of XMM-Newton data. All XMM-Newton calls for observing proposals are highly oversubscribed by factors of six and more. In the following some scientic highlights of XMM-Newton observations of black holes are summarized.

Association in Long-Evans hooded rats of red cell 2,3-diphosphoglycerate levels with hemoglobin types.

Science.gov (United States)

Brewer, G; Gilman, J; Noble, N; Crews, V

1978-08-01

Two sublines of commercially available Long-Evans hooded rats have been developed by genetic selection. These sublines have widely differing levels of erythrocyte 2,3-diphosphoglycerate (DPG) due to different alleles at a single genetic locus. In the present work, it is shown that rats from the commercial population are also polymorphic at a hemoglobin locus, probably involving two alleles of the IIIbeta-globin chain locus. Particular hemoglobin types have been found to be strongly associated with certain DPG types, not only in the high-DPG and low-DPG lines but also in the commercial population. Two explanations for this association are considered. One is a single-locus hypothesis, with hemoglobin allelic variation causing DPG variation, and the other is a two-locus hypothesis, with marked linkage disequilibrium.

Educational pathways of Black women physicists: Stories of experiencing and overcoming obstacles in life

Science.gov (United States)

Rosa, Katemari

2017-01-01

This talk presents an empirical study on the underrepresentation of people of color in scientific careers. Grounded in Critical Race Theory, the presentation examines the lived experiences of six Black women physicists in the United States, addresses obstacles faced in their career paths, and strategies used to overcome these obstacles. Data for this study were collected through semi-structured interviews and coded for emergent themes, which are invitation to engage in science, communities of science practices, and isolation in the academy. The findings reveal that college recruitment and funding were fundamental for these women to choose Physics over other STEM fields. The analysis shows Physics can be a hostile environment for these women. In addition, Black women experience unique challenges of socialization in Physics, particularly by exclusion of study groups. In this talk, suggestions will be presented to make Physics departments a more inclusive space to support Black women in science. This presentation is based on work supported by the Brazilian government through CAPES (BEX1907-07-7), the Fulbright Program, Comissño Fulbright Brasil, and the Office of Diversity at Teachers College, Columbia University.

Precocious Supermassive Black Holes Challenge Theories

Science.gov (United States)

2004-11-01

NASA's Chandra X-ray Observatory has obtained definitive evidence that a distant quasar formed less than a billion years after the Big Bang contains a fully-grown supermassive black hole generating energy at the rate of twenty trillion Suns. The existence of such massive black holes at this early epoch of the Universe challenges theories of the formation of galaxies and supermassive black holes. Astronomers Daniel Schwartz and Shanil Virani of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA observed the quasar, known as SDSSp J1306, which is 12.7 billion light years away. Since the Universe is estimated to be 13.7 billion years old, we see the quasar as it was a billion years after the Big Bang. They found that the distribution of X-rays with energy, or X-ray spectrum, is indistinguishable from that of nearby, older quasars. Likewise, the relative brightness at optical and X-ray wavelengths of SDSSp J1306 was similar to that of the nearby group of quasars. Optical observations suggest that the mass of the black hole is about a billion solar masses. Illustration of Quasar SDSSp J1306 Illustration of Quasar SDSSp J1306 Evidence of another early-epoch supermassive black hole was published previously by a team of scientists from the California Institute of Technology and the United Kingdom using the XMM-Newton X-ray satellite. They observed the quasar SDSSp J1030 at a distance of 12.8 billion light years and found essentially the same result for the X-ray spectrum as the Smithsonian scientists found for SDSSp J1306. Chandra's precise location and spectrum for SDSSp J1306 with nearly the same properties eliminate any lingering uncertainty that precocious supermassive black holes exist. "These two results seem to indicate that the way supermassive black holes produce X-rays has remained essentially the same from a very early date in the Universe," said Schwartz. "This implies that the central black hole engine in a massive galaxy was formed very soon

VLBA Reveals Closest Pair of Supermassive Black Holes

Science.gov (United States)

2006-05-01

Astronomers using the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope have found the closest pair of supermassive black holes ever discovered in the Universe -- a duo of monsters that together are more than 150 million times more massive than the Sun and closer together than the Earth and the bright star Vega. The VLBA The VLBA CREDIT: NRAO/AUI/NSF "These two giant black holes are only about 24 light-years apart, and that's more than 100 times closer than any pair found before," said Cristina Rodriguez, of the University of New Mexico (UNM) and Simon Bolivar University in Venezuela. Black holes are concentrations of mass with gravity so strong that not even light can escape them. The black hole pair is in the center of a galaxy called 0402+379, some 750 million light-years from Earth. Astronomers presume that each of the supermassive black holes was once at the core of a separate galaxy, then the two galaxies collided, leaving the black holes orbiting each other. The black holes orbit each other about once every 150,000 years, the scientists say. "If two black holes like these were to collide, that event would create the type of strong gravitational waves that physicists hope to detect with instruments now under construction," said Gregory Taylor, of UNM. The physicists will need to wait, though: the astronomers calculate that the black holes in 0402+379 won't collide for about a billion billion years. "There are some things that might speed that up a little bit," Taylor remarked. An earlier VLBA study of 0402+379, an elliptical galaxy, showed the pair of radio-wave-emitting objects near its core. Further studies using the VLBA and the Hobby-Eberly Telescope in Texas, revealed that the pair of objects is indeed a pair of supermassive black holes. "We needed the ultra-sharp radio 'vision' of the VLBA, particularly at the high radio frequencies of 22 and 43 GigaHertz, to get the detail needed to show that those objects are a pair of

Black holes

International Nuclear Information System (INIS)

Feast, M.W.

1981-01-01

This article deals with two questions, namely whether it is possible for black holes to exist, and if the answer is yes, whether we have found any yet. In deciding whether black holes can exist or not the central role in the shaping of our universe played by the forse of gravity is discussed, and in deciding whether we are likely to find black holes in the universe the author looks at the way stars evolve, as well as white dwarfs and neutron stars. He also discusses the problem how to detect a black hole, possible black holes, a southern black hole, massive black holes, as well as why black holes are studied

The role of glycogen, glucose and lactate in neuronal activity during hypoxia in the hooded seal (Cystophora cristata) brain.

Science.gov (United States)

Czech-Damal, N U; Geiseler, S J; Hoff, M L M; Schliep, R; Ramirez, J-M; Folkow, L P; Burmester, T

2014-09-05

The brains of diving mammals are repeatedly exposed to hypoxic conditions during diving. Brain neurons of the hooded seal (Cystophora cristata) have been shown to be more hypoxia tolerant than those of mice, but the underlying mechanisms are not clear. Here we investigated the roles of different metabolic substrates for maintenance of neuronal activity and integrity, by comparing the in vitro spontaneous neuronal activity of brain slices from layer V of the visual cortex of hooded seals with those in mice (Mus musculus). Studies were conducted by manipulating the composition of the artificial cerebrospinal fluid (aCSF), containing either 10 mM glucose, or 20 mM lactate, or no external carbohydrate supply (aglycemia). Normoxic, hypoxic and ischemic conditions were applied. The lack of glucose or the application of lactate in the aCSF containing no glucose had little effect on the neuronal activity of seal neurons in either normoxia or hypoxia, while neurons from mice survived in hypoxia only few minutes regardless of the composition of the aCSF. We propose that seal neurons have higher intrinsic energy stores. Indeed, we found about three times higher glycogen stores in the seal brain (∼4.1 ng per μg total protein in the seal cerebrum) than in the mouse brain. Notably, in aCSF containing no glucose, seal neurons can tolerate 20 mM lactate while in mouse neuronal activity vanished after few minutes even in normoxia. This can be considered as an adaptation to long dives, during which lactate accumulates in the blood. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Transcriptome Analysis Identifies Key Metabolic Changes in the Hooded Seal (Cystophora cristata Brain in Response to Hypoxia and Reoxygenation.

Directory of Open Access Journals (Sweden)

Mariana Leivas Müller Hoff

Full Text Available The brain of diving mammals tolerates low oxygen conditions better than the brain of most terrestrial mammals. Previously, it has been demonstrated that the neurons in brain slices of the hooded seal (Cystophora cristata withstand hypoxia longer than those of mouse, and also tolerate reduced glucose supply and high lactate concentrations. This tolerance appears to be accompanied by a shift in the oxidative energy metabolism to the astrocytes in the seal while in terrestrial mammals the aerobic energy production mainly takes place in neurons. Here, we used RNA-Seq to compare the effect of hypoxia and reoxygenation in vitro on brain slices from the visual cortex of hooded seals. We saw no general reduction of gene expression, suggesting that the response to hypoxia and reoxygenation is an actively regulated process. The treatments caused the preferential upregulation of genes related to inflammation, as found before e.g. in stroke studies using mammalian models. Gene ontology and KEGG pathway analyses showed a downregulation of genes involved in ion transport and other neuronal processes, indicative for a neuronal shutdown in response to a shortage of O2 supply. These differences may be interpreted in terms of an energy saving strategy in the seal's brain. We specifically analyzed the regulation of genes involved in energy metabolism. Hypoxia and reoxygenation caused a similar response, with upregulation of genes involved in glucose metabolism and downregulation of the components of the pyruvate dehydrogenase complex. We also observed upregulation of the monocarboxylate transporter Mct4, suggesting increased lactate efflux. Together, these data indicate that the seal brain responds to the hypoxic challenge by a relative increase in the anaerobic energy metabolism.

Winds of Change: How Black Holes May Shape Galaxies

Science.gov (United States)

2010-03-01

portion of the gas is pulled into the black hole, but some of it is blown away. High energy X-rays produced by the gas near the black hole heat the ouflowing gas, causing it to glow at lower X-ray energies. This Chandra study by Evans and his colleagues is much deeper than previous X-ray observations. It allowed them to make a high-definition map of the cone-shaped volume lit up by the black hole and its winds. By combining measurement of the velocity of the clouds with estimates of the density of the gas, Evans and his colleagues showed that each year several times the mass of the Sun is being deposited out to large distances, about 3,000 light years from the black hole. The wind may carry enough energy to heat the surrounding gas and suppress extra star formation. "We have shown that even these middle-of-the-road black holes can pack a punch," said Evans. "I think the upshot is that these black holes are anything but ordinary." Further Chandra HETGS studies of other nearby galaxies will examine the impact of other AGN outflows, leading to improvements in our understanding of the evolution of both galaxies and black holes. "In the future, our own Galaxy's black hole may undergo similar activity, helping to shut down the growth of new stars in the central region of the Milky Way," said Evans. These new results provide a key comparison to previous work performed at Georgia State University and the Catholic University of America with the Hubble Space Telescope's STIS instrument. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass. More information, including images and other multimedia, can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov

Black silicon with black bus-bar strings

DEFF Research Database (Denmark)

Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

2016-01-01

We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by mask-less reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Black bus-bars were realized by oxidized copper resulting in reflectance below 3% in the entire visible wavelength range. The combination of these two technologies may result in aesthetic, all-black panels based on conventional, front-contacted solar cells...

Seismicity Induced by Groundwater Recharge at Mt. Hood, Oregon, and its Implications for Hydrogeologic Properties.

Science.gov (United States)

Saar, M. O.; Manga, M.

2002-12-01

seismicity at Mt. Hood, Oregon. We can use the time lag of about 120 days between the two records to estimate the regional hydraulic diffusivity (1 m2/s) and other hydrogeologic parameters (permeability ≈ 10-13 m2, vertical matrix compressibility ≈ 10-10 m2/N). These values are comparable with our results from coupled heat and groundwater flow studies that are based on bore hole temperature data at Mt. Hood.

Applications of hidden symmetries to black hole physics

International Nuclear Information System (INIS)

Frolov, Valeri

2011-01-01

This work is a brief review of applications of hidden symmetries to black hole physics. Symmetry is one of the most important concepts of the science. In physics and mathematics the symmetry allows one to simplify a problem, and often to make it solvable. According to the Noether theorem symmetries are responsible for conservation laws. Besides evident (explicit) spacetime symmetries, responsible for conservation of energy, momentum, and angular momentum of a system, there also exist what is called hidden symmetries, which are connected with higher order in momentum integrals of motion. A remarkable fact is that black holes in four and higher dimensions always possess a set ('tower') of explicit and hidden symmetries which make the equations of motion of particles and light completely integrable. The paper gives a general review of the recently obtained results. The main focus is on understanding why at all black holes have something (symmetry) to hide.

Black Holes: Eliminating Information or Illuminating New Physics?

Directory of Open Access Journals (Sweden)

Sumanta Chakraborty

2017-07-01

Full Text Available Black holes, initially thought of as very interesting mathematical and geometric solutions of general relativity, over time, have come up with surprises and challenges for modern physics. In modern times, they have started to test our confidence in the fundamental understanding of nature. The most serious charge on the black holes is that they eat up information, never to release and subsequently erase it. This goes absolutely against the sacred principles of all other branches of fundamental sciences. This realization has shaken the very base of foundational concepts, both in quantum theory and gravity, which we always took for granted. Attempts to get rid of of this charge, have led us to crossroads with concepts, hold dearly in quantum theory. The sphere of black hole’s tussle with quantum theory has readily and steadily grown, from the advent of the Hawking radiation some four decades back, into domain of quantum information theory in modern times, most aptly, recently put in the form of the firewall puzzle. Do black holes really indicate something sinister about their existence or do they really point towards the troubles of ignoring the fundamental issues, our modern theories are seemingly plagued with? In this review, we focus on issues pertaining to black hole evaporation, the development of the information loss paradox, its recent formulation, the leading debates and promising directions in the community.

Black rings

International Nuclear Information System (INIS)

Emparan, Roberto; Reall, Harvey S

2006-01-01

A black ring is a five-dimensional black hole with an event horizon of topology S 1 x S 2 . We provide an introduction to the description of black rings in general relativity and string theory. Novel aspects of the presentation include a new approach to constructing black ring coordinates and a critical review of black ring microscopics. (topical review)

Chandra Catches "Piranha" Black Holes

Science.gov (United States)

2007-07-01

had good evidence until now," said co-author Paul Martini, also of OSU. "This can help solve a couple of mysteries about galaxy clusters." One mystery is why there are so many blue, star-forming galaxies in young, distant clusters and fewer in nearby, older clusters. AGN are believed to expel or destroy cool gas in their host galaxy through powerful eruptions from the black hole. This may stifle star formation and the blue, massive stars will then gradually die off, leaving behind only the old, redder stars. This process takes about a billion years or more to take place, so a dearth of star-forming galaxies is only noticeable for older clusters. The process that sets the temperature of the hot gas in clusters when they form is also an open question. These new results suggest that even more AGN may have been present when most clusters were forming about ten billion years ago. Early heating of a cluster by large numbers of AGN can have a significant, long-lasting effect on the structure of a cluster by "puffing up" the gas. "In a few nearby clusters we've seen evidence for huge eruptions generated by supermassive black holes. But this is sedate compared to what might be going on in younger clusters," said Eastman. These results appeared in the July 20th issue of The Astrophysical Journal Letters. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. Additional information and images are available at: Additional information and images are available at: http://chandra.harvard.edu and http://chandra.nasa.gov

"Black Like Me": Reframing Blackness for Decolonial Politics

Science.gov (United States)

Dei, George J. Sefa

2018-01-01

From a particular vantage point, as an African-born scholar with a politics to affirm my Black subjectivity and Indigeneity in a diasporic context, my article engages a (re)theorization of Blackness for decolonial politics. Building on existing works of how Black scholars, themselves, have theorized Blackness, and recognizing the fluid,…

Coffee, Black Holes, Editors, and Beer: The Science-Writing Life

Science.gov (United States)

Francis, Matthew R.

2016-01-01

What does a science writer do all day? In a tough job market and the pressures of the publish-or-perish life, careers outside academia are enticing. But it's not just a matter of swapping research papers for news stories, or adapting course lectures to magazine articles. I am a former academic scientist (with a PhD in physics and astronomy, as well as six years of university teaching) who now works as a freelance science journalist. In this talk, I'll share my experiences, along with a brief guide to the science-writing life. Along the way, we'll touch on misconceptions ("I love teaching, so science writing should be easy!"), bad attitudes ("dumbing down" is a concept that should be nuked from orbit), and the joys of sharing science with others. There are some hard truths: don't choose science writing because you think it's an easy option compared with academic research. Nevertheless, it's a rewarding profession, and one that allows you to remember the love of science — and share that love with large numbers of other people.

NASA Observatory Confirms Black Hole Limits

Science.gov (United States)

2005-02-01

cosmic time. Such "cosmic downsizing" was previously observed for galaxies undergoing star formation. These results connect well with the observations of nearby galaxies, which find that the mass of a supermassive black hole is proportional to the mass of the central region of its host galaxy. The other co-authors on the paper in the February 2005 issue of The Astronomical Journal were Len Cowie, Wei-Hao Wang, and Peter Capak (Institute for Astronomy, Univ. of Hawaii), Yuxuan Yang (GSFC and the Univ. of Maryland, College Park), and Aaron Steffen (Univ. of Wisconsin, Madison). NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for NASA's Space Mission Directorate, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW, Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. Additional information and images are available at: http://chandra.harvard.edu and http://chandra.nasa.gov

Massive Black Hole Implicated in Stellar Destruction

Science.gov (United States)

2010-01-01

of Alabama who led the study. Irwin and his colleagues obtained optical spectra of the object using the Magellan I and II telescopes in Las Campanas, Chile. These data reveal emission from gas rich in oxygen and nitrogen but no hydrogen, a rare set of signals from globular clusters. The physical conditions deduced from the spectra suggest that the gas is orbiting a black hole of at least 1,000 solar masses. The abundant amount of oxygen and absence of hydrogen indicate that the destroyed star was a white dwarf, the end phase of a solar-type star that has burned its hydrogen leaving a high concentration of oxygen. The nitrogen seen in the optical spectrum remains an enigma. "We think these unusual signatures can be explained by a white dwarf that strayed too close to a black hole and was torn apart by the extreme tidal forces," said coauthor Joel Bregman of the University of Michigan. Theoretical work suggests that the tidal disruption-induced X-ray emission could stay bright for more than a century, but it should fade with time. So far, the team has observed there has been a 35% decline in X-ray emission from 2000 to 2008. The ULX in this study is located in NGC 1399, an elliptical galaxy about 65 million light years from Earth. Irwin presented these results at the 215th meeting of the American Astronomical Society in Washington, DC. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass. More information, including images and other multimedia, can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov

Provoking misunderstanding: a comment on Black's defence of value-free sociology.

Science.gov (United States)

Hammersley, Martyn

2014-09-01

This paper is a response to a recent article dealing with the concept of value-free sociology by Donald Black. It argues that while a defence of Weber's position on the role of values in sociological research is necessary and important, what is offered by Black is counter-productive in important respects. This is because it encourages some of the misunderstandings that it is aimed at remedying and, even more importantly, offers a simplistic discussion of what are complex issues. © London School of Economics and Political Science 2014.

Black Alcoholism.

Science.gov (United States)

Watts, Thomas D.; Wright, Roosevelt

1988-01-01

Examines some aspects of the problem of alcoholism among Blacks, asserting that Black alcoholism can best be considered in an ecological, environmental, sociocultural, and public health context. Notes need for further research on alcoholism among Blacks and for action to reduce the problem of Black alcoholism. (NB)

Resonance – Journal of Science Education | News

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education. Film Review. Articles in Resonance – Journal of Science Education. Volume 22 Issue 3 March 2017 pp 317-318 Film Review. The Untold Story of NASA's Trailblazers: Hidden Figures sheds light on the contributions of black women to the US Space Race.

Tests for the existence of black holes through gravitational wave echoes

Science.gov (United States)

Cardoso, Vitor; Pani, Paolo

2017-09-01

The existence of black holes and spacetime singularities is a fundamental issue in science. Despite this, observations supporting their existence are scarce, and their interpretation is unclear. In this Perspective we outline the case for black holes that has been made over the past few decades, and provide an overview of how well observations adjust to this paradigm. Unsurprisingly, we conclude that observational proof for black holes is, by definition, impossible to obtain. However, just like Popper's black swan, alternatives can be ruled out or confirmed to exist with a single observation. These observations are within reach. In the coming years and decades, we will enter an era of precision gravitational-wave physics with more sensitive detectors. Just as accelerators have required larger and larger energies to probe smaller and smaller scales, more sensitive gravitational-wave detectors will probe regions closer and closer to the horizon, potentially reaching Planck scales and beyond. What may be there, lurking?

Black Holes, Gravitational Waves, and LISA

Science.gov (United States)

Baker, John

2009-01-01

Binary black hole mergers are central to many key science objectives of the Laser Interferometer Space Antenna (LISA). For many systems the strongest part of the signal is only understood by numerical simulations. Gravitational wave emissions are understood by simulations of vacuum General Relativity (GR). I discuss numerical simulation results from the perspective of LISA's needs, with indications of work that remains to be done. Some exciting scientific opportunities associated with LISA observations would be greatly enhanced if prompt electromagnetic signature could be associated. I discuss simulations to explore this possibility. Numerical simulations are important now for clarifying LISA's science potential and planning the mission. We also consider how numerical simulations might be applied at the time of LISA's operation.

The regeneration of a multi-ethnic mixed-use area: The case of Robin Hood Chase

Directory of Open Access Journals (Sweden)

Ian Bentley

1997-01-01

Full Text Available Urban designers show increasing interest in promoting community participation in urban regeneration and especially housing regeneration. However, effective participation has proved difficult in multi-ethnic mixed-use areas, with their wide range of different (and often conflicting interest groups. This paper, presented in case-study form, analyses a project in one such area: the Robin Hood Chase local centre in St. Ann’s area of Nottingham. It pays particular attention to the identification of different interest groups and their associated institutions, the use of local media and social events to involve these groups in the urban design process, the use of rearrangeable models in a process of “enquiry by design”, and the production of a widely acceptable urban design strategy for the area. Analysis of feedback from participants indicates a high level of satisfaction both with the final physical design proposal and with the process itself; and also identifies directions for further development in the approach and techniques employed.

The Death of Imhotep: A Hermeneutical Framework for Understanding the Lack of Black Males in STEM Fields

Science.gov (United States)

Mocombe, Paul C.

2018-01-01

In Afrocentric circles in the United States, ancient Kemetic (Egyptian) scientist Imhotep is considered the Black father of medicine. In this article, I use his name in the title as an allusion to highlight the lack of Black males matriculating in science, technology, engineering, and mathematics (STEM) programs or fields in the United States. The…

Black holes

OpenAIRE

Brügmann, B.; Ghez, A. M.; Greiner, J.

2001-01-01

Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries.

Levels of non-essential elements in muscle from harp seal (Phagophilus groenlandicus) and hooded seal (Cystophora cristata) caught in the Greenland Sea area

International Nuclear Information System (INIS)

Brunborg, Linn Anne; Graff, Ingvild Eide; Froyland, Livar; Julshamn, Kare

2006-01-01

The non-essential elements, arsenic, cadmium, mercury and lead, inevitably accumulate in marine top predators such as seals. The concentration of these elements and the essential element selenium, due to its proposed protective properties against mercury toxicity in marine mammals, were measured in muscle, liver and kidney from reproductive active females of harp seal (Phagophilus groenlandicus) and hooded seal (Cystophora cristata) caught in the drift ice between Iceland and East Greenland. Arsenic levels were below 1 μg/g w.w. in all analysed samples, and were therefore low compared to other seafood products. The concentrations of arsenic found in the present study were comparable to the results reported in a similar study from 1985. Mean concentrations of total mercury in muscle from the present study were higher than levels in other seafood products. The levels of total mercury from the present study showed a tendency of lower levels in all tissue samples compared to the study from 1985. Methyl mercury displayed a trend of a lower ratio of methyl mercury to total mercury as the concentration of total mercury increased, indicating a demethylation of methyl mercury at high total mercury concentrations (e.g. mercury in liver of hooded seal). The concentration ratio of methyl mercury to total mercury in muscle samples was more than 75%, with total mercury concentration less than 0.5 μg/g w.w., whereas the ratio for liver was as low as 0.2% with a total mercury concentration of 128 μg/g w.w. The molar concentration ratios of selenium to mercury showed that selenium was present in a molar surplus to mercury in all tissues with low mercury concentration. However, there seemed to be a general mobilisation of selenium in liver and kidney tissues of harp seal and hooded seal, whereas an extraordinary mobilisation seemed to take place at hepatic mercury concentrations exceeding 50 μg/g w.w. The mean concentrations of lead in muscles in the present study were higher

The phase structure of higher-dimensional black rings and black holes

International Nuclear Information System (INIS)

Emparan, Roberto; Harmark, Troels; Niarchos, Vasilis; Obers, Niels A.; RodrIguez, Maria J.

2007-01-01

We construct an approximate solution for an asymptotically flat, neutral, thin rotating black ring in any dimension D ≥ 5 by matching the near-horizon solution for a bent boosted black string, to a linearized gravity solution away from the horizon. The rotating black ring solution has a regular horizon of topology S 1 x S D-3 and incorporates the balancing condition of the ring as a zero-tension condition. For D = 5 our method reproduces the thin ring limit of the exact black ring solution. For D ≥ 6 we show that the black ring has a higher entropy than the Myers-Perry black hole in the ultra-spinning regime. By exploiting the correspondence between ultra-spinning black holes and black membranes on a two-torus, we take steps towards qualitatively completing the phase diagram of rotating blackfolds with a single angular momentum. We are led to propose a connection between MP black holes and black rings, and between MP black holes and black Saturns, through merger transitions involving two kinds of 'pinched' black holes. More generally, the analogy suggests an infinite number of pinched black holes of spherical topology leading to a complicated pattern of connections and mergers between phases

PREDICTORS OF INFANT AND TODDLER BLACK BOYS' EARLY LEARNING: SEIZING OPPORTUNITIES AND MINIMIZING RISKS.

Science.gov (United States)

Iruka, Iheoma U

2017-01-01

Using the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B) data set (U.S. Department of Education Institute of Education Sciences, National Center for Education Statistics, 2001), this study examined child, family, and community factors in the early years (infant and toddler years) to predict the cognitive and language outcomes for preschool-age Black boys in relation to Black girls and White boys. Findings indicate that Black children face many challenges, with Black boys experiencing less sensitive parenting as compared to their peers. We live in a highly complex, racialized environment. While there are universal indicators that predict children's preschool outcomes such as strong social positioning and positive parenting, there are, in addition, some indicators that are more beneficial for Black boys' early development, including a stable, less urban home environment with parents engaging in "tough love." © 2016 Michigan Association for Infant Mental Health.

Supersonic gas streams enhance the formation of massive black holes in the early universe.

Science.gov (United States)

Hirano, Shingo; Hosokawa, Takashi; Yoshida, Naoki; Kuiper, Rolf

2017-09-29

The origin of super-massive black holes in the early universe remains poorly understood. Gravitational collapse of a massive primordial gas cloud is a promising initial process, but theoretical studies have difficulty growing the black hole fast enough. We report numerical simulations of early black hole formation starting from realistic cosmological conditions. Supersonic gas motions left over from the Big Bang prevent early gas cloud formation until rapid gas condensation is triggered in a protogalactic halo. A protostar is formed in the dense, turbulent gas cloud, and it grows by sporadic mass accretion until it acquires 34,000 solar masses. The massive star ends its life with a catastrophic collapse to leave a black hole-a promising seed for the formation of a monstrous black hole. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

On the Charter Question: Black Marxism and Black Nationalism

Science.gov (United States)

Stern, Mark; Hussain, Khuram

2015-01-01

This article brings two black intellectual traditions to bear on the question of charter schools: black Marxism and black nationalism. The authors examine the theoretical and rhetorical devices used to talk about charters schools by focusing on how notions of "black liberation" are deployed by the charter movement, and to what end. The…

"Be Real Black for Me": Imagining BlackCrit in Education

Science.gov (United States)

Dumas, Michael J.; ross, kihana miraya

2016-01-01

The authors put forward a theorization of a Black Critical Theory, or what might be called BlackCrit, within, and in response to, Critical Race Theory, and then outline ways that BlackCrit in education helps us to more incisively analyze how the specificity of (anti)blackness matters in explaining how Black bodies become marginalized, disregarded,…

Black hole astrophysics

International Nuclear Information System (INIS)

Blandford, R.D.; Thorne, K.S.

1979-01-01

Following an introductory section, the subject is discussed under the headings: on the character of research in black hole astrophysics; isolated holes produced by collapse of normal stars; black holes in binary systems; black holes in globular clusters; black holes in quasars and active galactic nuclei; primordial black holes; concluding remarks on the present state of research in black hole astrophysics. (U.K.)

Surprise: Dwarf Galaxy Harbors Supermassive Black Hole

Science.gov (United States)

2011-01-01

The surprising discovery of a supermassive black hole in a small nearby galaxy has given astronomers a tantalizing look at how black holes and galaxies may have grown in the early history of the Universe. Finding a black hole a million times more massive than the Sun in a star-forming dwarf galaxy is a strong indication that supermassive black holes formed before the buildup of galaxies, the astronomers said. The galaxy, called Henize 2-10, 30 million light-years from Earth, has been studied for years, and is forming stars very rapidly. Irregularly shaped and about 3,000 light-years across (compared to 100,000 for our own Milky Way), it resembles what scientists think were some of the first galaxies to form in the early Universe. "This galaxy gives us important clues about a very early phase of galaxy evolution that has not been observed before," said Amy Reines, a Ph.D. candidate at the University of Virginia. Supermassive black holes lie at the cores of all "full-sized" galaxies. In the nearby Universe, there is a direct relationship -- a constant ratio -- between the masses of the black holes and that of the central "bulges" of the galaxies, leading them to conclude that the black holes and bulges affected each others' growth. Two years ago, an international team of astronomers found that black holes in young galaxies in the early Universe were more massive than this ratio would indicate. This, they said, was strong evidence that black holes developed before their surrounding galaxies. "Now, we have found a dwarf galaxy with no bulge at all, yet it has a supermassive black hole. This greatly strengthens the case for the black holes developing first, before the galaxy's bulge is formed," Reines said. Reines, along with Gregory Sivakoff and Kelsey Johnson of the University of Virginia and the National Radio Astronomy Observatory (NRAO), and Crystal Brogan of the NRAO, observed Henize 2-10 with the National Science Foundation's Very Large Array radio telescope and

Transformative practices in secondary school science classrooms: Life histories of Black South African teachers

Science.gov (United States)

Jita, Loyiso Currell

1999-11-01

This study investigated the construction of teaching practices that are aimed at including all students in learning the key ideas of science and helping them to develop a voice for participating in the discourses in and outside of the science classroom. Such practices define what in this study is referred to as transformative practice. The study tells the stories of three Black secondary school teachers in South Africa who have worked to construct a transformative practice in their biology and physical science classrooms. Using a life history perspective, the study explored the relationships between teachers' identities and the changes in their classroom practices. Data were collected mainly through periodic interviews with the teachers and observations of their teaching practices over a period of 18 months. An important finding of the study was that the classroom practices of all three teachers were defined by three similar themes of: (1) "covering the content" and preparing their students to succeed in the national examinations, (2) developing deep conceptual understandings of the subject matter, and (3) including all students in their teaching by constructing what other researchers have called a "culturally-relevant" pedagogy. This finding was consistent despite the observed variations of context and personal histories. A major finding of this study on the question of the relationship between identity and teaching practice was that despite the importance of context, subject matter, material and social resources, another category of resources---the "resources of biography"---proved to be crucial for each of the teachers in crafting a transformative pedagogy. These "resources of biography" included such things as the teachers' own experiences of marginalization, the experiences of growing up or living in a particular culture, and the experiences of participating in certain kinds of social, political, religious or professional activities. The study suggests that it

The Gender and Race-Ethnicity of Faculty in Top Science and Engineering Research Departments

Science.gov (United States)

Beutel, Ann M.; Nelson, Donna J.

This study examines the gender and racial-ethnic composition of faculty in top research departments for science and engineering "S-E - disciplines. There are critical masses of at least 15% women in top research departments in biological sciences, psychology, and social sciences but not in physical sciences and engineering. Blacks and Hispanics together make up only 4.1% of the faculty in our study. Black and Hispanic females are the most poorly represented groups; together, they make up only 1% of the faculty in top S-E research departments. For most S-E disciplines, less than 15% of full professors in top research departments are women or non-Whites.

Nine optical black-box experiments for lower-secondary students

Science.gov (United States)

Rode, Henning; Friege, Gunnar

2017-05-01

In this paper a sequence of nine, easy to manufacture optical black-box experiments with increasing levels of difficulty, and supportive frameworks for physics classes are introduced. They have been evaluated in a lower-secondary school at the end of optics lessons. A black-box is a kind of experimental task where the inner structure is not visible to the experimenter. Using mirrors, beam-splitters, and blockers in a black-box to manipulate the light beam’s direction through this specific experiment, students are instructed to vary input and observe the output of light to get an idea of the possible inner structure. The presented sequence of black-box experiments requires a basic knowledge of the linear propagation of light and is suitable for beginner physics. Furthermore a framework for concrete implementation to physics classes is given, which covers suitable structure of class, examples for helpful worksheets, and authentic students’ solutions. The difficulty of the specific black-box experiments is given by the students’ success within observing input-output correlation and conclusion of an inner structure. The experiments’ implementation to physics classes may cover elaboration, practice, and aspects of the nature of science even in a beginner’s class. Evaluation has been conducted with students of young age (11-12 years old), however they are suitable for older students also. Although dealing with a time extensive sequence of experiments, students showed a high level of motivation throughout. Overall, implementing this sequence of black-box experiments is seen as valuable and helpful for physics classes.

Contemporary Black Theatre.

Science.gov (United States)

Thomas, Pearl

The distinguishable black theatre in America, mirroring a distinguishable black experience, is an artistic product which demands audience involvement. Both the Afro-American oral tradition and the art of gesture are integral aspects of black theatre. In addition, the tragedy found black theatre is not tragedy in the classic sense, as blacks feel…

Lidar-enhanced geologic mapping, examples from the Medford and Hood River areas, Oregon

Science.gov (United States)

Wiley, T. J.; McClaughry, J. D.

2012-12-01

Lidar-based 3-foot digital elevation models (DEMs) and derivatives (slopeshade, hillshade, contours) were used to help map geology across 1700 km2 (650 mi2) near Hood River and Medford, Oregon. Techniques classically applied to interpret coarse DEMs and small-scale topographic maps were adapted to take advantage of lidar's high resolution. Penetration and discrimination of plant cover by the laser system allowed recognition of fine patterns and textures related to underlying geologic units and associated soils. Surficial geologic maps were improved by the ability to examine tiny variations in elevation and slope. Recognition of low-relief features of all sizes was enhanced where pixel elevation ranges of centimeters to meters, established by knowledge of the site or by trial, were displayed using thousands of sequential colors. Features can also be depicted relative to stream level by preparing a DEM that compensates for gradient. Near Medford, lidar-derived contour maps with 1- to 3-foot intervals revealed incised bajada with young, distal lobes defined by concentric contour lines. Bedrock geologic maps were improved by recognizing geologic features associated with surface textures and patterns or topographic anomalies. In sedimentary and volcanic terrain, structure was revealed by outcrops or horizons lying at one stratigraphic level. Creating a triangulated irregular network (TIN) facet from positions of three or more such points gives strike and dip. Each map area benefited from hundreds of these measurements. A more extensive DEM in the plane of the TIN facet can be subtracted from surface elevation (lidar DEM) to make a DEM with elevation zero where the stratigraphic horizon lies at the surface. The distribution of higher and lower stratigraphic horizons can be shown by highlighting areas similarly higher or lower on the same DEM. Poor fit of contacts or faults projected between field traverses suggest the nature and amount of intervening geologic structure

Caged black holes: Black holes in compactified spacetimes. I. Theory

International Nuclear Information System (INIS)

Kol, Barak; Sorkin, Evgeny; Piran, Tsvi

2004-01-01

In backgrounds with compact dimensions there may exist several phases of black objects including a black hole and a black string. The phase transition between them raises questions and touches on fundamental issues such as topology change, uniqueness, and cosmic censorship. No analytic solution is known for the black hole, and moreover one can expect approximate solutions only for very small black holes, while phase transition physics happens when the black hole is large. Hence we turn to numerical solutions. Here some theoretical background to the numerical analysis is given, while the results will appear in a subsequent paper. The goals for a numerical analysis are set. The scalar charge and tension along the compact dimension are defined and used as improved order parameters which put both the black hole and the black string at finite values on the phase diagram. The predictions for small black holes are presented. The differential and the integrated forms of the first law are derived, and the latter (Smarr's formula) can be used to estimate the 'overall numerical error'. Field asymptotics and expressions for physical quantities in terms of the numerical values are supplied. The techniques include the 'method of equivalent charges', free energy, dimensional reduction, and analytic perturbation for small black holes

Primary black holes

International Nuclear Information System (INIS)

Novikov, I.; Polnarev, A.

1981-01-01

Proves are searched for of the formation of the so-called primary black holes at the very origin of the universe. The black holes would weigh less than 10 13 kg. The formation of a primary black hole is conditional on strong fluctuations of the gravitational field corresponding roughly to a half of the fluctuation maximally permissible by the general relativity theory. Only big fluctuations of the gravitational field can overcome the forces of the hot gas pressure and compress the originally expanding matter into a black hole. Low-mass black holes have a temperature exceeding that of the black holes formed from stars. A quantum process of particle formation, the so-called evaporation takes place in the strong gravitational field of a black hole. The lower the mass of the black hole, the shorter the evaporation time. The analyses of processes taking place during the evaporation of low-mass primary black holes show that only a very small proportion of the total mass of the matter in the universe could turn into primary black holes. (M.D.)

77 FR 70423 - Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC...

Science.gov (United States)

2012-11-26

... Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of..., 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor) and Black Bear Development Holdings, LLC and Black Bear SO, LLC (transferees) filed an application for the partial the transfer of licenses...

Residential and service-population exposure to multiple natural hazards in the Mount Hood region of Clackamas County, Oregon

Science.gov (United States)

Mathie, Amy M.; Wood, Nathan

2013-01-01

The objective of this research is to document residential and service-population exposure to natural hazards in the rural communities of Clackamas County, Oregon, near Mount Hood. The Mount Hood region of Clackamas County has a long history of natural events that have impacted its small, tourism-based communities. To support preparedness and emergency-management planning in the region, a geospatial analysis of population exposure was used to determine the number and type of residents and service populations in flood-, wildfire-, and volcano-related hazard zones. Service populations are a mix of residents and tourists temporarily benefitting from local services, such as retail, education, or recreation. In this study, service population includes day-use visitors at recreational sites, overnight visitors at hotels and resorts, children at schools, and community-center visitors. Although the heavily-forested, rural landscape suggests few people are in the area, there are seasonal peaks of thousands of visitors to the region. “Intelligent” dasymetric mapping efforts using 30-meter resolution land-cover imagery and U.S. Census Bureau data proved ineffective at adequately capturing either the spatial distribution or magnitude of population at risk. Consequently, an address-point-based hybrid dasymetric methodology of assigning population to the physical location of buildings mapped with a global positioning system was employed. The resulting maps of the population (1) provide more precise spatial distributions for hazard-vulnerability assessments, (2) depict appropriate clustering due to higher density structures, such as apartment complexes and multi-unit commercial buildings, and (3) provide new information on the spatial distribution and temporal variation of people utilizing services within the study area. Estimates of population exposure to flooding, wildfire, and volcanic hazards were determined by using overlay analysis in a geographic information system

Phase transition for black holes with scalar hair and topological black holes

International Nuclear Information System (INIS)

Myung, Yun Soo

2008-01-01

We study phase transitions between black holes with scalar hair and topological black holes in asymptotically anti-de Sitter spacetimes. As the ground state solutions, we introduce the non-rotating BTZ black hole in three dimensions and topological black hole with hyperbolic horizon in four dimensions. For the temperature matching only, we show that the phase transition between black hole with scalar hair (Martinez-Troncoso-Zanelli black hole) and topological black hole is second-order by using differences between two free energies. However, we do not identify what order of the phase transition between scalar and non-rotating BTZ black holes occurs in three dimensions, although there exists a possible decay of scalar black hole to non-rotating BTZ black hole

Galaxy evolution. Black hole feedback in the luminous quasar PDS 456.

Science.gov (United States)

Nardini, E; Reeves, J N; Gofford, J; Harrison, F A; Risaliti, G; Braito, V; Costa, M T; Matzeu, G A; Walton, D J; Behar, E; Boggs, S E; Christensen, F E; Craig, W W; Hailey, C J; Matt, G; Miller, J M; O'Brien, P T; Stern, D; Turner, T J; Ward, M J

2015-02-20

The evolution of galaxies is connected to the growth of supermassive black holes in their centers. During the quasar phase, a huge luminosity is released as matter falls onto the black hole, and radiation-driven winds can transfer most of this energy back to the host galaxy. Over five different epochs, we detected the signatures of a nearly spherical stream of highly ionized gas in the broadband x-ray spectra of the luminous quasar PDS 456. This persistent wind is expelled at relativistic speeds from the inner accretion disk, and its wide aperture suggests an effective coupling with the ambient gas. The outflow's kinetic power larger than 10(46) ergs per second is enough to provide the feedback required by models of black hole and host galaxy coevolution. Copyright © 2015, American Association for the Advancement of Science.

From binary black hole simulation to triple black hole simulation

International Nuclear Information System (INIS)

Bai Shan; Cao Zhoujian; Han, Wen-Biao; Lin, Chun-Yu; Yo, Hwei-Jang; Yu, Jui-Ping

2011-01-01

Black hole systems are among the most promising sources for a gravitational wave detection project. Now, China is planning to construct a space-based laser interferometric detector as a follow-on mission of LISA in the near future. Aiming to provide some theoretical support to this detection project on the numerical relativity side, we focus on black hole systems simulation in this work. Considering the globular galaxy, multiple black hole systems also likely to exist in our universe and play a role as a source for the gravitational wave detector we are considering. We will give a progress report in this paper on our black hole system simulation. More specifically, we will present triple black hole simulation together with binary black hole simulation. On triple black hole simulations, one novel perturbational method is proposed.

Variational data assimilation system "INM RAS - Black Sea"

Science.gov (United States)

Parmuzin, Eugene; Agoshkov, Valery; Assovskiy, Maksim; Giniatulin, Sergey; Zakharova, Natalia; Kuimov, Grigory; Fomin, Vladimir

2013-04-01

Development of Informational-Computational Systems (ICS) for Data Assimilation Procedures is one of multidisciplinary problems. To study and solve these problems one needs to apply modern results from different disciplines and recent developments in: mathematical modeling; theory of adjoint equations and optimal control; inverse problems; numerical methods theory; numerical algebra and scientific computing. The problems discussed above are studied in the Institute of Numerical Mathematics of the Russian Academy of Science (INM RAS) in ICS for Personal Computers (PC). Special problems and questions arise while effective ICS versions for PC are being developed. These problems and questions can be solved with applying modern methods of numerical mathematics and by solving "parallelism problem" using OpenMP technology and special linear algebra packages. In this work the results on the ICS development for PC-ICS "INM RAS - Black Sea" are presented. In the work the following problems and questions are discussed: practical problems that can be studied by ICS; parallelism problems and their solutions with applying of OpenMP technology and the linear algebra packages used in ICS "INM - Black Sea"; Interface of ICS. The results of ICS "INM RAS - Black Sea" testing are presented. Efficiency of technologies and methods applied are discussed. The work was supported by RFBR, grants No. 13-01-00753, 13-05-00715 and by The Ministry of education and science of Russian Federation, project 8291, project 11.519.11.1005 References: [1] V.I. Agoshkov, M.V. Assovskii, S.A. Lebedev, Numerical simulation of Black Sea hydrothermodynamics taking into account tide-forming forces. Russ. J. Numer. Anal. Math. Modelling (2012) 27, No.1, 5-31 [2] E.I. Parmuzin, V.I. Agoshkov, Numerical solution of the variational assimilation problem for sea surface temperature in the model of the Black Sea dynamics. Russ. J. Numer. Anal. Math. Modelling (2012) 27, No.1, 69-94 [3] V.B. Zalesny, N.A. Diansky, V

Giant black hole rips star apart

Science.gov (United States)

2004-02-01

satellite and is helping to solve many cosmic mysteries of the violent Universe, from black holes to the formation of galaxies. It was launched on 10 December 1999, using an Ariane-5 rocket, from French Guiana. It is expected to return data for a decade. XMM-Newton's high-tech design uses over 170 wafer-thin cylindrical mirrors spread over three telescopes. Its orbit takes it almost a third of the way to the Moon, so that astronomers can enjoy long, uninterrupted views of celestial objects. NASA's Marshall Space Flight Center, Huntsville, Alabama, manages the Chandra programme for the Office of Space Science, NASA Headquarters, Washington DC, USA. Northrop Grumman of Redondo Beach, California, formerly TRW Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Massachusetts.

Surface geometry of 5D black holes and black rings

International Nuclear Information System (INIS)

Frolov, Valeri P.; Goswami, Rituparno

2007-01-01

We discuss geometrical properties of the horizon surface of five-dimensional rotating black holes and black rings. Geometrical invariants characterizing these 3D geometries are calculated. We obtain a global embedding of the 5D rotating black horizon surface into a flat space. We also describe the Kaluza-Klein reduction of the black ring solution (along the direction of its rotation) which, though it is nakedly singular, relates this solution to the 4D metric of a static black hole distorted by the presence of external scalar (dilaton) and vector ('electromagnetic') fields. The properties of the reduced black hole horizon and its embedding in E 3 are briefly discussed

Black Holes

OpenAIRE

Townsend, P. K.

1997-01-01

This paper is concerned with several not-quantum aspects of black holes, with emphasis on theoretical and mathematical issues related to numerical modeling of black hole space-times. Part of the material has a review character, but some new results or proposals are also presented. We review the experimental evidence for existence of black holes. We propose a definition of black hole region for any theory governed by a symmetric hyperbolic system of equations. Our definition reproduces the usu...

Black silicon solar cells with black bus-bar strings

DEFF Research Database (Denmark)

Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

2016-01-01

We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by maskless reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Four different methods to obtain blackened bus-bar strings were compared with respect to reflectance, and two of these methods (i.e., oxidized copper and etched solder) were used to fabricate functional allblack solar 9-cell panels. The black bus-bars (e.......g., by oxidized copper) have a reflectance below 3% in the entire visible wavelength range. The combination of black silicon cells and blackened bus-bars results in aesthetic, all-black panels based on conventional, front-contacted solar cells without compromising efficiency....

The Black Rock Forest Consortium: A narrative

Science.gov (United States)

Buzzetto-More, Nicole Antoinette

The Black Rock Forest is a 3,785-acre wilderness area whose richly forested landscape represents the splendor of the Hudson Valley Region of New York State. Although originally intended to become the home of wealthy banker James Stillman, it was his son Ernest whose love of conservation caused him to embrace the then new and revolutionary practice of sustainable forestry and establish Black Rock in 1928. Due to Ernest Stillman's foresight, the property was protected from development and bequeathed to Harvard University following his death for the establishment of an experimental forest. The modern environmental movement in America began when the Black Rock Forest was threatened with development by Consolidated Edison, and the people of the surrounding community banded together, battling tirelessly for over 17 years to stop the degradation of this historic forest. The outcome of this crusade marked a hallmark win for the environment leaving an illustrious and inveterate legacy. The campaign resulted in the watershed legislation the National Environmental Policy Act, the formation of several environmental advocacy groups, the creation of the Council on Environmental Quality of the Executive Office of the President, as well as set a precedent for communities to initiate and win cases against major corporations in order to safeguard natural resources. In the midst of the controversy it became apparent that alternative futures for the Forest needed to be explored. As a result of a committee report and one man's vision, the idea emerged to create a consortium that would purchase and steward the Forest. With a formation that took nearly fifteen years, the Black Rock Forest Consortium was formed, a unique amalgamation of K--12 public and private schools, colleges and universities, and science and cultural centers that successfully collaborate to enhance scientific research, environmental conservation, and education. The Consortium works to bridge the gaps between learners

The Escalation of Business as Usual

Science.gov (United States)

Tuchman, Gaye

2011-01-01

An academic plan is a business plan disguised in the regalia donned for significant public ceremonies--black cap and gown, colorful hood, and, of course, gold tassel. Several years ago, the University of Connecticut started to plan for the economic disaster that was at the time so obviously in the future of higher education institutions. A formal…

Effects of racialized tracking on racial gaps in science self-efficacy, identity, engagement, and aspirations: Connection to science and school segregation

Science.gov (United States)

Chang, Briana L.

Given the concentration of economic growth and power in science fields and the current levels of racial stratification in schooling, this study examined (1) the effects of race on students' connectedness to science and career aspirations, (2) the extent to which these effects were moderated by school racial composition and racialized tracking, and (3) the differences in modeling effects using separate variables for race and gender (i.e., White, Black, Hispanic, female) versus race/gender (e.g., White female, Black male, etc.). Using the lens of racial formation theory, this study situated access to science knowledge as a racial project, conferring and denying access to resources along racial lines. Reviews of the literature on science self-efficacy, identity, engagement, and career aspirations revealed an under-emphasis on school institutional factors, such as racial composition and racialized tracking (which are important in sociological literature), as shaping student outcomes. The study analyzed data from the nationally representative High School Longitudinal Study that surveyed students in 2009 during their freshman year in high school and again in 2012 during most students' junior year (n = 6,998). Affective ratings (in self-efficacy, identity, engagement) and career aspirations for students measured in 2012 were examined as dependent variables and a variable for racialized tracking was estimated given schools' placement of students in advanced science coursework in 2012. Although school racial composition was not found to moderate race on outcome effects, primary analyses demonstrated that the presence of racialized tracking in the students' schools did moderate these effects. Overall these results suggested that the student subgroups most often at a disadvantage compared to White students for the science outcomes studied were Hispanic males and females; Black students' ratings and aspirations were largely on par or exceeded those of their White counterparts

Ghost Remains After Black Hole Eruption

Science.gov (United States)

2009-05-01

NASA's Chandra X-ray Observatory has found a cosmic "ghost" lurking around a distant supermassive black hole. This is the first detection of such a high-energy apparition, and scientists think it is evidence of a huge eruption produced by the black hole. This discovery presents astronomers with a valuable opportunity to observe phenomena that occurred when the Universe was very young. The X-ray ghost, so-called because a diffuse X-ray source has remained after other radiation from the outburst has died away, is in the Chandra Deep Field-North, one of the deepest X-ray images ever taken. The source, a.k.a. HDF 130, is over 10 billion light years away and existed at a time 3 billion years after the Big Bang, when galaxies and black holes were forming at a high rate. "We'd seen this fuzzy object a few years ago, but didn't realize until now that we were seeing a ghost", said Andy Fabian of the Cambridge University in the United Kingdom. "It's not out there to haunt us, rather it's telling us something - in this case what was happening in this galaxy billions of year ago." Fabian and colleagues think the X-ray glow from HDF 130 is evidence for a powerful outburst from its central black hole in the form of jets of energetic particles traveling at almost the speed of light. When the eruption was ongoing, it produced prodigious amounts of radio and X-radiation, but after several million years, the radio signal faded from view as the electrons radiated away their energy. HDF 130 Chandra X-ray Image of HDF 130 However, less energetic electrons can still produce X-rays by interacting with the pervasive sea of photons remaining from the Big Bang - the cosmic background radiation. Collisions between these electrons and the background photons can impart enough energy to the photons to boost them into the X-ray energy band. This process produces an extended X-ray source that lasts for another 30 million years or so. "This ghost tells us about the black hole's eruption long after

Synthesis of multiwalled carbon nanotube from different grades of carbon black using arc discharge method

Energy Technology Data Exchange (ETDEWEB)

Arora, Neha, E-mail: n4neha31@gmail.com [Department of Mechanical Engineering, Birla Institute of Technology and Science, Pilani (India); Sharma, N. N. [Department of Mechanical Engineering, Birla Institute of Technology and Science, Pilani (India); Director, School of Automobile, Mechanical & Mechatronics, Manipal University,Jaipur,India (India)

2016-04-13

This paper describes the synthesis of nanotube from different grades (Tread * A(non-ASTM), N134,N121,N660 and N330)of carbon black using DC arc discharge method at 40A current for 60sec. Carbon black samples of different grades were procured from industry (Aditya Birla Science and Technology Limited, India). Scanning Electron Micrographs (SEM) of the deposited carbon nanostructures suggests that MWCNTs are formed at 40A and for a minimal exposure time of 60sec.The result formed indicates the N330 grade of carbon black gets converted to MWCNTs (Multiwall Carbon nanotube) as compared to other grades.

Search for gravitational waves from primordial black hole binary coalescences in the galactic halo

International Nuclear Information System (INIS)

Abbott, B.; Anderson, S.B.; Araya, M.; Armandula, H.; Asiri, F.; Barish, B.C.; Barnes, M.; Barton, M.A.; Bhawal, B.; Billingsley, G.; Black, E.; Blackburn, K.; Bogue, L.; Bork, R.; Brown, D.A.; Busby, D.; Cardenas, L.; Chandler, A.; Chapsky, J.; Charlton, P.

2005-01-01

We use data from the second science run of the LIGO gravitational-wave detectors to search for the gravitational waves from primordial black hole binary coalescence with component masses in the range 0.2-1.0M · . The analysis requires a signal to be found in the data from both LIGO observatories, according to a set of coincidence criteria. No inspiral signals were found. Assuming a spherical halo with core radius 5 kpc extending to 50 kpc containing nonspinning black holes with masses in the range 0.2-1.0M · , we place an observational upper limit on the rate of primordial black hole coalescence of 63 per year per Milky Way halo (MWH) with 90% confidence

Distortion of Schwarzschild-anti-de Sitter black holes to black strings

International Nuclear Information System (INIS)

Tomimatsu, Akira

2005-01-01

Motivated by the existence of black holes with various topologies in four-dimensional spacetimes with a negative cosmological constant, we study axisymmetric static solutions describing any large distortions of Schwarzschild-anti-de Sitter black holes parametrized by the mass m. Under the approximation such that m is much larger than the anti-de Sitter radius, it is found that a cylindrically symmetric black string is obtained as a special limit of distorted spherical black holes. Such a prolonged distortion of the event horizon connecting a Schwarzschild-anti-de Sitter black hole to a black string is allowed without violating both the usual black hole thermodynamics and the hoop conjecture for the horizon circumference

Taking the Pulse of a Black Hole System

Science.gov (United States)

2011-01-01

away an enormous amount of matter, equivalent to one third the mass of the Moon per day! This effectively forces the black hole onto a severe diet, and we think it eventually has real consequences for the system's heartbeat," said co-author Julia Lee, associate professor in the Astronomy department at Harvard and Neilsen's thesis advisor. This massive wind drains material from the outer disk and after a couple weeks, this depletion affects the inner disk, causing the black hole to feed much more slowly and its X-ray brightness to decrease substantially. Unable to power such strong variations in the disk and the wind, GRS 1915's 'heart' ceases to beat. This remarkable system then likely begins one of its 13 other known patterns of variation. Neilsen is a winner of the Roger Doxsey Travel Prize, which provides graduate students within one year of receiving or receipt of their PhD a monetary prize to enable the oral presentation of their dissertation research at an AAS meeting. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass. More information, including images and other multimedia, can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov

Low-mass black holes as the remnants of primordial black hole formation.

Science.gov (United States)

Greene, Jenny E

2012-01-01

Bridging the gap between the approximately ten solar mass 'stellar mass' black holes and the 'supermassive' black holes of millions to billions of solar masses are the elusive 'intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ∼10(4)-10(5) M(⊙) black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism.

Black holes, wormholes and time machines

CERN Document Server

Al-Khalili, Jim

2011-01-01

Bringing the material up to date, Black Holes, Wormholes and Time Machines, Second Edition captures the new ideas and discoveries made in physics since the publication of the best-selling first edition. While retaining the popular format and style of its predecessor, this edition explores the latest developments in high-energy astroparticle physics and Big Bang cosmology.The book continues to make the ideas and theories of modern physics easily understood by anyone, from researchers to students to general science enthusiasts. Taking you on a journey through space and time, author Jim Al-Khalil

Resonance – Journal of Science Education | Indian Academy of ...

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education. Prajval Shastri. Articles written in Resonance – Journal of Science Education. Volume 22 Issue 3 March 2017 pp 237-244 General Article. Black Holes in Our Universe: Do They Inch Up the Mass Ladder? Prajval Shastri · More Details Abstract Fulltext PDF.

Black Culture

Directory of Open Access Journals (Sweden)

Angela Khristin Brown

2013-07-01

Full Text Available The migration of blacks in North America through slavery became united.  The population of blacks past downs a tradition of artist through art to native born citizens. The art tradition involved telling stories to each generation in black families. The black culture elevated by tradition created hope to determine their personal freedom to escape from poverty of enslavement and to establish a way of life through tradition. A way of personal freedoms was through getting a good education that lead to a better foundation and a better way of life.

Jet Power and Black Hole Assortment Revealed in New Chandra Image

Science.gov (United States)

2008-01-01

acceleration in this part of the jet is unknown. Hundreds of point-like sources are also seen in the Chandra image. Many of these are X-ray binaries that contain a stellar-mass black hole and a companion star in orbit around one another. Determining the population and properties of these black holes should help scientists better understand the evolution of massive stars and the formation of black holes. Another surprise was the detection of two particularly bright X-ray binaries. These sources may contain stellar mass black holes that are unusually massive, and this Chandra observation might have caught them gobbling up material at a high rate. In this image, low-energy X-rays are colored red, intermediate-energy X-rays are green, and the highest-energy X-rays detected by Chandra are blue. The dark green and blue bands running almost perpendicular to the jet are dust lanes that absorb X-rays. This dust lane was created when Centaurus A merged with another galaxy perhaps 100 million years ago. This research was presented at the American Astronomical Society meeting on January 9th by Gregory Sivakoff (The Ohio State University). Other team members include Ralph Kraft (Harvard-Smithsonian Center for Astrophysics), Martin Hardcastle (University of Hertfordshire), Diana Worrall (University of Bristol), and Andres Jordan (Smithsonian Astrophysical Observatory). NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

Magnetized black holes and black rings in the higher dimensional dilaton gravity

International Nuclear Information System (INIS)

Yazadjiev, Stoytcho S.

2006-01-01

In this paper we consider magnetized black holes and black rings in the higher dimensional dilaton gravity. Our study is based on exact solutions generated by applying a Harrison transformation to known asymptotically flat black hole and black ring solutions in higher dimensional spacetimes. The explicit solutions include the magnetized version of the higher dimensional Schwarzschild-Tangherlini black holes, Myers-Perry black holes, and five-dimensional (dipole) black rings. The basic physical quantities of the magnetized objects are calculated. We also discuss some properties of the solutions and their thermodynamics. The ultrarelativistic limits of the magnetized solutions are briefly discussed and an explicit example is given for the D-dimensional magnetized Schwarzschild-Tangherlini black holes

Never Before Seen: Two Supermassive Black Holes in Same Galaxy

Science.gov (United States)

2002-11-01

For the first time, scientists have proof two supermassive black holes exist together in the same galaxy, thanks to data from NASA's Chandra X-ray Observatory. These black holes are orbiting each other and will merge several hundred million years from now, to create an even larger black hole resulting in a catastrophic event that will unleash intense radiation and gravitational waves. The Chandra image reveals that the nucleus of an extraordinarily bright galaxy, known as NGC 6240, contains not one, but two giant black holes, actively accreting material from their surroundings. This discovery shows that massive black holes can grow through mergers in the centers of galaxies, and that these enigmatic events will be detectable with future space-borne gravitational wave observatories. "The breakthrough came with Chandra's ability to clearly distinguish the two nuclei, and measure the details of the X-radiation from each nucleus," said Guenther Hasinger, of the Max Planck Institute for Extraterrestrial Physics in Germany, a coauthor of an upcoming Astrophysical Journal Letters paper describing the research. "These cosmic fingerprints revealed features characteristic of supermassive black holes -- an excess of high-energy photons from gas swirling around a black hole, and X-rays from fluorescing iron atoms in gas near black holes," he said. Previous X-ray observatories had shown that the central region produces X-rays, while radio, infrared and optical observations had detected two bright nuclei, but the nature of this region remained a mystery. Astronomers did not know the location of the X-ray source, or the nature of the two bright nuclei. "With Chandra, we hoped to determine which one, if either, of the nuclei was an active supermassive black hole," said Stefanie Komossa, also of the Max Planck Institute, lead author of the paper on NGC 6240. "Much to our surprise, we found that both were active black holes!" At a distance of about 400 million light years, NGC 6240

Fort Hood Solar Total Energy Project. Volume II. Preliminary design. Part 2. System performance and supporting studies. Final report

Energy Technology Data Exchange (ETDEWEB)

None,

1979-01-01

The preliminary design developed for the Solar Total Energy System to be installed at Fort Hood, Texas, is presented. System performance analysis and evaluation are described. Feedback of completed performance analyses on current system design and operating philosophy is discussed. The basic computer simulation techniques and assumptions are described and the resulting energy displacement analysis is presented. Supporting technical studies are presented. These include health and safety and reliability assessments; solar collector component evaluation; weather analysis; and a review of selected trade studies which address significant design alternatives. Additional supporting studies which are generally specific to the installation site are reported. These include solar availability analysis; energy load measurements; environmental impact assessment; life cycle cost and economic analysis; heat transfer fluid testing; meteorological/solar station planning; and information dissemination. (WHK)

The Black Lives Matter Movement and Historically Black Colleges and Universities

Science.gov (United States)

Gasman, Marybeth

2017-01-01

This article looks at the Black Lives Matter Movement and Historically Black Colleges and Universities. Historically Black Colleges and Universities (HBCUs) continue to play an important role in society. However, what the Black Lives Matter movement shows consistently is that predominantly White institutions need to change, to step up and embrace…

Stars Form Surprisingly Close to Milky Way's Black Hole

Science.gov (United States)

2005-10-01

The supermassive black hole at the center of the Milky Way has surprisingly helped spawn a new generation of stars, according to observations from NASA's Chandra X-ray Observatory. This novel mode of star formation may solve several mysteries about the supermassive black holes that reside at the centers of nearly all galaxies. "Massive black holes are usually known for violence and destruction," said Sergei Nayakshin of the University of Leicester, United Kingdom, and coauthor of a paper on this research in an upcoming issue of the Monthly Notices of the Royal Astronomical Society. "So it's remarkable that this black hole helped create new stars, not just destroy them." Black holes have earned their fearsome reputation because any material -- including stars -- that falls within the so-called event horizon is never seen again. However, these new results indicate that the immense disks of gas known to orbit many black holes at a "safe" distance from the event horizon can help nurture the formation of new stars. Animation of Stars Forming Around Black Hole Animation of Stars Forming Around Black Hole This conclusion came from new clues that could only be revealed in X-rays. Until the latest Chandra results, astronomers have disagreed about the origin of a mysterious group of massive stars discovered by infrared astronomers to be orbiting less than a light year from the Milky Way's central black hole, a.k.a. Sagittarius A*, or Sgr A*. At such close distances to Sgr A*, the standard model for star formation predicts that gas clouds from which stars form should have been ripped apart by tidal forces from the black hole. Two models to explain this puzzle have been proposed. In the disk model, the gravity of a dense disk of gas around Sgr A* offsets the tidal forces and allows stars to form; in the migration model, the stars formed in a star cluster far away from the black hole and migrated in to form the ring of massive stars. The migration scenario predicts about a

Chandra Reviews Black Hole Musical: Epic But Off-Key

Science.gov (United States)

2006-10-01

give the strongest evidence to date of a shock wave produced by the supermassive black hole, a clear sign of a powerful explosion. This shock wave appears as a nearly circular ring of high-energy X-rays that is 85,000 light years in diameter and centered on the black hole. Other remarkable features are seen in M87 for the first time including narrow filaments of X-ray emission -- some over 100,000 light years long -- that may be due hot gas trapped by magnetic fields. Also, a large, previously unknown cavity in the hot gas, created by an outburst from the black hole about 70 million years ago, is seen in the X-ray image. Animation Showing a Supermassive Black Hole Outburst in M87 Animation Showing a Supermassive Black Hole Outburst in M87 "We can explain some of what we see, like the shock wave, with textbook physics," said team member Christine Jones, also of the CfA. "However, other details, like the filaments we find, leave us scratching our heads." Sound has been detected from another black hole in the Perseus cluster, which was calculated to have a note some 57 octaves below middle C. However, the sound in M87 appears to be more discordant and complex. A series of unevenly spaced loops in the hot gas gives evidence for small outbursts from the black hole about every 6 million years. These loops imply the presence of sound waves, not visible in the Chandra image, which are about 56 octaves below middle C. The presence of the large cavity and the sonic boom gives evidence for even deeper notes -- 58 or 59 octaves below middle C -- powered by large outbursts. These new results on M87 were presented at the High-Energy Astrophysics Division meeting being held in San Francisco. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center, Cambridge, Mass. Additional information and images are

University of Missouri research reactor exhaust ventilation/laboratory fume hood upgrade

International Nuclear Information System (INIS)

Edwards, C.B. Jr.; McKibben, J.C.; McCracken, C.B.

1989-01-01

The University of Missouri research reactor (MURR) facility is located in Research Park, 1 mile south of the Columbia campus. The reactor is a 10-MW pressurized loop, in-pool-type, light-water-moderated, beryllium-and-graphite-reflected core, serviced by six radial beam tubes for research, and has sample irradiation facilities in both a flux trap and in the graphite region. The reactor operates at full power 150 h/week, 52 week/yr, making it one of the best operating schedules and the most extensively used of any university research reactor. This extensive utilization includes many programs, such as radioisotope applications, neutron activation analysis, etc., that depend heavily on fume hoods, glove boxes, and hot cells that put a tremendous demand on the exhaust system. The exhaust system is required to be operable whenever the reactor is operating and must have the capability of being operated from an emergency electrical generator on loss of site electrical power. The originally installed exhaust ventilation system was below needed capacity and, with increased program requirements and system age, the necessity to upgrade the system was paramount. The challenge was to complete the upgrade construction while continuing to operate the reactor and maintain all the other ongoing programs, rather than take the easy way of an extended shutdown. This paper discusses how MURR met this challenge and solved these problems, problems that are similarly experienced by almost all research reactors to some degree when major work is required on critical systems

Black hole levitron

International Nuclear Information System (INIS)

Arsiwalla, Xerxes D.; Verlinde, Erik P.

2010-01-01

We study the problem of spatially stabilizing four dimensional extremal black holes in background electric/magnetic fields. Whilst looking for stationary stable solutions describing black holes placed in external fields we find that taking a continuum limit of Denef et al.'s multicenter supersymmetric black hole solutions provides a supergravity description of such backgrounds within which a black hole can be trapped within a confined volume. This construction is realized by solving for a levitating black hole over a magnetic dipole base. We comment on how such a construction is akin to a mechanical levitron.

Black Holes

OpenAIRE

Horowitz, Gary T.; Teukolsky, Saul A.

1998-01-01

Black holes are among the most intriguing objects in modern physics. Their influence ranges from powering quasars and other active galactic nuclei, to providing key insights into quantum gravity. We review the observational evidence for black holes, and briefly discuss some of their properties. We also describe some recent developments involving cosmic censorship and the statistical origin of black hole entropy.

Search for black holes

International Nuclear Information System (INIS)

Cherepashchuk, Anatolii M

2003-01-01

Methods and results of searching for stellar mass black holes in binary systems and for supermassive black holes in galactic nuclei of different types are described. As of now (June 2002), a total of 100 black hole candidates are known. All the necessary conditions Einstein's General Relativity imposes on the observational properties of black holes are satisfied for candidate objects available, thus further assuring the existence of black holes in the Universe. Prospects for obtaining sufficient criteria for reliably distinguishing candidate black holes from real black holes are discussed. (reviews of topical problems)

Noncommutative black holes

Energy Technology Data Exchange (ETDEWEB)

Lopez-DomInguez, J C [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); Obregon, O [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); RamIrez, C [Facultad de Ciencias FIsico Matematicas, Universidad Autonoma de Puebla, PO Box 1364, 72000 Puebla (Mexico); Sabido, M [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico)

2007-11-15

We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole.

CSIR ScienceScope: Women in science

CSIR Research Space (South Africa)

CSIR

2006-08-01

Full Text Available of a SET career ladder is in process, the results of which I anticipate will not reflect an abundance of women in top science or management positions. There is still no female CSIR fellow, however, for the first time in our history we have a black... they perceive the opportunities available to them. The CSIR recently went through a change process, which is not yet complete – we need to consider interventions to accelerate the movement of women through the organisation’s SET career ladder. It is clear...

Authoring Identity amidst the Treacherous Terrain of Science: A Multiracial Feminist Examination of the Journeys of Three Women of Color in Science

Science.gov (United States)

Johnson, Angela; Brown, Jaweer; Carlone, Heidi; Cuevas, Azita K.

2011-01-01

The study of the identity processes of women of color in science-based fields helps us (a) find ways to support similar women, and (b) study the dynamics of inequity, within and beyond science. Participants in this study (a Black woman, a Latina, and an American Indian woman) survived inadequate high schools and discouraging college science…

NASA-HBCU Space Science and Engineering Research Forum Proceedings

International Nuclear Information System (INIS)

Sanders, Y.D.; Freeman, Y.B.; George, M.C.

1989-01-01

The proceedings of the Historically Black Colleges and Universities (HBCU) forum are presented. A wide range of research topics from plant science to space science and related academic areas was covered. The sessions were divided into the following subject areas: Life science; Mathematical modeling, image processing, pattern recognition, and algorithms; Microgravity processing, space utilization and application; Physical science and chemistry; Research and training programs; Space science (astronomy, planetary science, asteroids, moon); Space technology (engineering, structures and systems for application in space); Space technology (physics of materials and systems for space applications); and Technology (materials, techniques, measurements)

Special data base of Informational - Computational System 'INM RAS - Black Sea' for solving inverse and data assimilation problems

Science.gov (United States)

Zakharova, Natalia; Piskovatsky, Nicolay; Gusev, Anatoly

2014-05-01

Development of Informational-Computational Systems (ICS) for data assimilation procedures is one of multidisciplinary problems. To study and solve these problems one needs to apply modern results from different disciplines and recent developments in: mathematical modeling; theory of adjoint equations and optimal control; inverse problems; numerical methods theory; numerical algebra and scientific computing. The above problems are studied in the Institute of Numerical Mathematics of the Russian Academy of Science (INM RAS) in ICS for personal computers. In this work the results on the Special data base development for ICS "INM RAS - Black Sea" are presented. In the presentation the input information for ICS is discussed, some special data processing procedures are described. In this work the results of forecast using ICS "INM RAS - Black Sea" with operational observation data assimilation are presented. This study was supported by the Russian Foundation for Basic Research (project No 13-01-00753) and by Presidium Program of Russian Academy of Sciences (project P-23 "Black sea as an imitational ocean model"). References 1. V.I. Agoshkov, M.V. Assovskii, S.A. Lebedev, Numerical simulation of Black Sea hydrothermodynamics taking into account tide-forming forces. Russ. J. Numer. Anal. Math. Modelling (2012) 27, No.1, pp. 5-31. 2. E.I. Parmuzin, V.I. Agoshkov, Numerical solution of the variational assimilation problem for sea surface temperature in the model of the Black Sea dynamics. Russ. J. Numer. Anal. Math. Modelling (2012) 27, No.1, pp. 69-94. 3. V.B. Zalesny, N.A. Diansky, V.V. Fomin, S.N. Moshonkin, S.G. Demyshev, Numerical model of the circulation of Black Sea and Sea of Azov. Russ. J. Numer. Anal. Math. Modelling (2012) 27, No.1, pp. 95-111. 4. Agoshkov V.I.,Assovsky M.B., Giniatulin S. V., Zakharova N.B., Kuimov G.V., Parmuzin E.I., Fomin V.V. Informational Computational system of variational assimilation of observation data "INM RAS - Black sea"// Ecological

Black hole critical phenomena without black holes

Indian Academy of Sciences (India)

large values of Ф, black holes do form and for small values the scalar field ... on the near side of the ridge ultimately evolve to form black holes while those configu- ... The inset shows a bird's eye view looking down on the saddle point.

Black widow spider

Science.gov (United States)

... medlineplus.gov/ency/article/002858.htm Black widow spider To use the sharing features on this page, please enable JavaScript. The black widow spider (Latrodectus) has a shiny black body with a ...

USSTRIDE program is associated with competitive Black and Latino student applicants to medical school

Directory of Open Access Journals (Sweden)

Kendall M. Campbell

2014-05-01

Full Text Available Purpose: We compared MCAT scores, grade point averages (GPAs, and medical school acceptance rates of Black and Latino students in an outreach program called Undergraduate Science Students Together Reaching Instructional Diversity and Excellence (USSTRIDE to non-USSTRIDE students. We hypothesized that Black and Latino participants in USSTRIDE had higher acceptance rates to medical school, higher MCAT scores, and college GPAs when compared to other Black and Latino medical school applicants from our institution. Methods: The academic performance (GPAs and MCAT scores and acceptance and matriculation rate data on all Black and Latino Florida State University applicants to any medical school from 2008 to 2012 were collected from the AIS/AMCAS database and separated into two comparison groups (USSTRIDE vs. Non-USSTRIDE. Independent sample T-tests and chi-square analysis, Cohen's D test, and odds ratios were determined. Results: Average science GPA was 3.47 for USSTRIDE students (n=55 and 3.45 for non-USSTRIDE students (n=137, p=0.68, d=0.0652. Average cumulative GPA was 3.57 for USSTRIDE students and 3.54 for non-USSTRIDE students (p=0.45, d=0.121. Average MCAT score was 23 for USSTRIDE students and 25 for non-USSTRIDE students (p=0.02, d=0.378. Twenty-three percent of accepted USSTRIDE students and 29% of accepted non-USSTRIDE students had multiple acceptances (p=0.483, OR 1.38, 95% CI 0.52–3.88. Forty-nine percent of non-USSTRIDE students and 75% of USSTRIDE students matriculated in medical school (p=0.001, OR 3.13 95% CI 1.51–6.74. About 78.6% of USSTRIDE students matriculated at FSU's medical school compared to 36.2% of non-USSTRIDE students (p<0.01. Conclusions: USSTRIDE and non-USSTRIDE students had similar science and cumulative GPAs. USSTRIDE students' MCAT scores were lower but acceptance rates to medical school were higher. Participation in USSTRIDE is associated with increased acceptance rates for Black and Latino students to our

A Dose–Response Analysis of the Reproductive Effects of a Single Gestational Dose of 2,3,7,8-Tetrachlorodibenzo-p-dioxin in Male Long Evans Hooded Rat Offspring,

OpenAIRE

Gray, L. E.; Ostby, J. S.; Kelce, W. R.

1997-01-01

Male rats exposedin uteroto 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) display reduced fertility as a consequence of the direct action of TCDD on the epididymides, as well as delayed puberty and altered reproductive organ weights. The current study provides dose–response data for the reproductive effects of TCDD, administered during pregnancy, with an emphasis on the effects of TCDD on testicular, epididymal, and ejaculated sperm numbers. Long Evans Hooded rats were dosed by gavage with 0, 0....

A Dancing Black Hole

Science.gov (United States)

Shoemaker, Deirdre; Smith, Kenneth; Schnetter, Erik; Fiske, David; Laguna, Pablo; Pullin, Jorge

2002-04-01

Recently, stationary black holes have been successfully simulated for up to times of approximately 600-1000M, where M is the mass of the black hole. Considering that the expected burst of gravitational radiation from a binary black hole merger would last approximately 200-500M, black hole codes are approaching the point where simulations of mergers may be feasible. We will present two types of simulations of single black holes obtained with a code based on the Baumgarte-Shapiro-Shibata-Nakamura formulation of the Einstein evolution equations. One type of simulations addresses the stability properties of stationary black hole evolutions. The second type of simulations demonstrates the ability of our code to move a black hole through the computational domain. This is accomplished by shifting the stationary black hole solution to a coordinate system in which the location of the black hole is time dependent.

Era of Galaxy and Black Hole Growth Spurt Discovered

Science.gov (United States)

2005-04-01

Universe that they can be detected at all. "The deeper we look into the Universe with Chandra, the more fascinating things we find" says Niel Brandt of Penn State University in University Park. "Who knows what nature has in store for us as we push the boundaries yet further." The X-ray observations also showed that the black holes are surrounded by a dense shroud of gas and dust. This is probably the material that will be consumed by the growing black holes. Hubble Space Telescope observations indicate that most of the submillimeter galaxies are actually two galaxies that are colliding and merging. Recent sophisticated computer simulations performed by Tiziana Di Matteo of Carnegie Mellon University in Pittsburgh, Penn., and her collaborators have shown that such mergers drive gas toward the central regions of galaxies, triggering a burst of star formation and providing fuel for the growth of a central black hole. Chandra's X-ray Image of Black Holes in the Early Universe Chandra's X-ray Image of Black Holes in the Early Universe "It is exciting that these recent observations are in good agreement with our simulation," says Di Matteo, "We seem to be converging on a consistent picture of galaxy formation with both observations and theory." In particular, this work will help scientists to understand the observed link in the present epoch between the total mass of stars in the central bulges of large galaxies and the size of their central, supermassive black holes. The James Clerk Maxwell Telescope (JCMT) is operated on behalf of the United Kingdom, Canada & Netherlands by the Joint Astronomy Centre. With its 15-meter (50-foot) diameter dish the JCMT detects light with "submillimeter" wavelengths, between infrared light and radio waves on the wavelength scale. The W. M. Keck Observatory is operated by the California Association for Research in Astronomy. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate

New Panorama Reveals More Than a Thousand Black Holes

Science.gov (United States)

2007-03-01

By casting a wide net, astronomers have captured an image of more than a thousand supermassive black holes. These results give astronomers a snapshot of a crucial period when these monster black holes are growing, and provide insight into the environments in which they occur. The new black hole panorama was made with data from NASA's Chandra X-ray Observatory, the Spitzer Space Telescope and ground-based optical telescopes. The black holes in the image are hundreds of millions to several billion times more massive than the sun and lie in the centers of galaxies. X-ray, IR & Optical Composites of Obscured & Unobscured AGN in Bootes Field X-ray, IR & Optical Composites of Obscured & Unobscured AGN in Bootes Field Material falling into these black holes at high rates generates huge amounts of light that can be detected in different wavelengths. These systems are known as active galactic nuclei, or AGN. "We're trying to get a complete census across the Universe of black holes and their habits," said Ryan Hickox of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass. "We used special tactics to hunt down the very biggest black holes." Instead of staring at one relatively small part of the sky for a long time, as with the Chandra Deep Fields -- two of the longest exposures obtained with the observatory -- and other concentrated surveys, this team scanned a much bigger portion with shorter exposures. Since the biggest black holes power the brightest AGN, they can be spotted at vast distances, even with short exposures. Scale Chandra Images to Full Moon Scale Chandra Images to Full Moon "With this approach, we found well over a thousand of these monsters, and have started using them to test our understanding of these powerful objects," said co-investigator Christine Jones, also of the CfA. The new survey raises doubts about a popular current model in which a supermassive black hole is surrounded by a doughnut-shaped region, or torus, of gas. An

The Doctorate Production and Baccalaureate Origins of African Americans in the Sciences and Engineering.

Science.gov (United States)

Solorzano, Daniel G.

1995-01-01

Reviews the status of black doctorate production from U.S. universities during the 1980s, updating baseline information and examining the baccalaureate origins of African American doctorates. Black students continue to be underrepresented, especially in science and engineering, and gender differences persist. The role of historically black…

Black Swans and the Effectiveness of Remediating Groundwater Contamination

Science.gov (United States)

Siegel, D. I.; Otz, M. H.; Otz, I.

2013-12-01

Black swans, outliers, dominate science far more than do predictable outcomes. Predictable success constitutes the Black Swan in groundwater remediation. Even the National Research Council concluded that remediating groundwater to drinking water standards has failed in typically complex hydrogeologic settings where heterogeneities and preferential flow paths deflect flow paths obliquely to hydraulic gradients. Natural systems, be they biological or physical, build upon a combination of large-scale regularity coupled to chaos at smaller scales. We show through a review of over 25 case studies that groundwater remediation efforts are best served by coupling parsimonious site characterization to natural and induced geochemical tracer tests to at least know where contamination advects with groundwater in the subsurface. In the majority of our case studies, actual flow paths diverge tens of degrees from anticipated flow paths because of unrecognized heterogeneities in the horizontal direction of transport, let alone the vertical direction. Consequently, regulatory agencies would better serve both the public and the environment by recognizing that long-term groundwater cleanup probably is futile in most hydrogeologic settings except to relaxed standards similar to brownfielding. A Black Swan

Who Will Do Science? Trends, and Their Causes in Minority and Female Representation among Holders of Advanced Degrees in Science and Mathematics. A Special Report.

Science.gov (United States)

Berryman, Sue E.

This paper describes trends in and causes of minority and female representation among holders of advanced science and math degrees. The minority groups studied are Blacks, Hispanic Americans, American Indians, and Asian Americans, all of whom are compared with Whites. The degrees looked at include those in math, the computer sciences, physical…

Gender, Ethnicity, and Physics Education: Understanding How Black Women Build Their Identities as Scientists

Science.gov (United States)

Rosa, Katemari Diogo da

This research focuses on the underrepresentation of minoritized groups in scientific careers. The study is an analysis of the relationships between race, gender, and those with careers in the sciences, focusing on the lived experiences of Black women physicists, as viewed through the lens of women scientists in the United States. Although the research is geographically localized, the base-line question is clear and mirrors in the researcher's own intellectual development: "How do Black women physicists describe their experiences towards the construction of a scientific identity and the pursuit of a career in physics?" Grounded on a critical race theory perspective, the study uses storytelling to analyze how these women build their identities as scientists and how they have negotiate their multiple identities within different communities in society. Findings show that social integration is a key element for Black women physicists to enter study groups, which enables access to important resources for academic success in STEM. The study has implications for physics education and policymakers. The study reveals the role of the different communities that these women are part of, and the importance of public policies targeted to increase the participation of underrepresented groups in science, especially through after-school programs and financial support through higher education.

Astrophysical black holes

CERN Document Server

Gorini, Vittorio; Moschella, Ugo; Treves, Aldo; Colpi, Monica

2016-01-01

Based on graduate school lectures in contemporary relativity and gravitational physics, this book gives a complete and unified picture of the present status of theoretical and observational properties of astrophysical black holes. The chapters are written by internationally recognized specialists. They cover general theoretical aspects of black hole astrophysics, the theory of accretion and ejection of gas and jets, stellar-sized black holes observed in the Milky Way, the formation and evolution of supermassive black holes in galactic centers and quasars as well as their influence on the dynamics in galactic nuclei. The final chapter addresses analytical relativity of black holes supporting theoretical understanding of the coalescence of black holes as well as being of great relevance in identifying gravitational wave signals. With its introductory chapters the book is aimed at advanced graduate and post-graduate students, but it will also be useful for specialists.

Natural ventilation of a generic cask under a transport hood - CFD and analytical modelling

Energy Technology Data Exchange (ETDEWEB)

Powell, D.; Davies, G.; Tso, C.F. [Arup, London (United Kingdom)

2004-07-01

In comparison with finite element simulation for structural and thermal behaviour, the use of computational fluid dynamics technique (hereafter CFD) to analyse, predict and design air and heat flow in package design is relatively novel. Arup has been using CFD techniques to investigate fluid and heat flow, and to use it as a tool to design fluid and heat flow across a broad spectrum of industries for over fifteen years. In order demonstrate the power of the technique and its benefits, the airflow and heat flow characteristics around a transport package during transit under a transport hood has been evaluated using the CFD technique. This paper presents the scenario, the model, the analysis technique and the results of this analysis. Comparison with test results is probably the best way to validate a CFD analysis. In the absence of test results, the analysis was verified by comparison with hand calculation solutions. The scenario as it stands is too complex and hand calculation solution cannot describe the scenario sufficiently. However, hand calculation solutions could be derived for simplified version of the scenario against which CFD analysis of the simplified scenario can be compared. The second half of this paper describes the verification out.

Natural ventilation of a generic cask under a transport hood - CFD and analytical modelling

International Nuclear Information System (INIS)

Powell, D.; Davies, G.; Tso, C.F.

2004-01-01

In comparison with finite element simulation for structural and thermal behaviour, the use of computational fluid dynamics technique (hereafter CFD) to analyse, predict and design air and heat flow in package design is relatively novel. Arup has been using CFD techniques to investigate fluid and heat flow, and to use it as a tool to design fluid and heat flow across a broad spectrum of industries for over fifteen years. In order demonstrate the power of the technique and its benefits, the airflow and heat flow characteristics around a transport package during transit under a transport hood has been evaluated using the CFD technique. This paper presents the scenario, the model, the analysis technique and the results of this analysis. Comparison with test results is probably the best way to validate a CFD analysis. In the absence of test results, the analysis was verified by comparison with hand calculation solutions. The scenario as it stands is too complex and hand calculation solution cannot describe the scenario sufficiently. However, hand calculation solutions could be derived for simplified version of the scenario against which CFD analysis of the simplified scenario can be compared. The second half of this paper describes the verification out

Lumpy AdS5× S5 black holes and black belts

International Nuclear Information System (INIS)

Dias, Óscar J.C.; Santos, Jorge E.; Way, Benson

2015-01-01

Sufficiently small Schwarzschild black holes in global AdS 5 ×S 5 are Gregory-Laflamme unstable. We construct new families of black hole solutions that bifurcate from the onset of this instability and break the full SO(6) symmetry group of the S 5 down to SO(5). These new “lumpy" solutions are labelled by the harmonics ℓ. We find evidence that the ℓ=1 branch never dominates the microcanonical/canonical ensembles and connects through a topology-changing merger to a localised black hole solution with S 8 topology. We argue that these S 8 black holes should become the dominant phase in the microcanonical ensemble for small enough energies, and that the transition to Schwarzschild black holes is first order. Furthermore, we find two branches of solutions with ℓ=2. We expect one of these branches to connect to a solution containing two localised black holes, while the other branch connects to a black hole solution with horizon topology S 4 ×S 4 which we call a “black belt”.

Black holes in binary stars

NARCIS (Netherlands)

Wijers, R.A.M.J.

1996-01-01

Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes

Black Interpretation, Black American Literature, and Grey Audiences.

Science.gov (United States)

Washington, Earl M.

1981-01-01

Defines and illustrates language techniques used by Black authors writing to and for Blacks in the 1960s and 1970s. Suggests how language and theme barriers of such literature might be overcome in a contemporary integrated oral interpretation classroom. (PD)

#BlackBabiesMatter: Analyzing Black Religious Media in Conservative and Progressive Evangelical Communities

Directory of Open Access Journals (Sweden)

Monique Moultrie

2017-11-01

Full Text Available This article explores how conservative and progressive black Protestants interrogate the theological theme of the sacrality of black life through digital media. The innovations of religious media in black evangelical communities remain an understudied phenomenon in African American religion, making this an apt arena for further discovery. This current intervention into the study of African American Religion examines digital activism through examples of religious media produced by blacks for black audiences. This article begins its interrogation of the sacrality of black life by juxtaposing those who contend that Black Babies Matter as pro-birth-oriented, religiously motivated activists with those religious opponents asserting Black Lives Matter who present an intersectional pro-life approach. The comparison of views relies on womanist cultural analysis as its main methodology to analyze and interpret digital media and explore its ramifications for African American Religion.

Black holes. Chapter 6

International Nuclear Information System (INIS)

Penrose, R.

1980-01-01

Conditions for the formation of a black hole are considered, and the properties of black holes. The possibility of Cygnus X-1 as a black hole is discussed. Einstein's theory of general relativity in relation to the formation of black holes is discussed. (U.K.)

Black ringoids: spinning balanced black objects in d≥5 dimensions — the codimension-two case

International Nuclear Information System (INIS)

Kleihaus, Burkhard; Kunz, Jutta; Radu, Eugen

2015-01-01

We propose a general framework for the study of asymptotically flat black objects with k+1 equal magnitude angular momenta in d≥5 spacetime dimensions (with 0≤k≤[((d−5)/2)]). In this approach, the dependence on all angular coordinates but one is factorized, which leads to a codimension-two problem. This framework can describe black holes with spherical horizon topology, the simplest solutions corresponding to a class of Myers-Perry black holes. A different set of solutions describes balanced black objects with S"n"+"1×S"2"k"+"1 horizon topology. The simplest members of this family are the black rings (k=0). The solutions with k>0 are dubbed black ringoids. Based on the nonperturbative numerical results found for several values of (n,k), we propose a general picture for the properties and the phase diagram of these solutions and the associated black holes with spherical horizon topology: n=1 black ringoids repeat the k=0 pattern of black rings and Myers-Perry black holes in 5 dimensions, whereas n>1 black ringoids follow the pattern of higher dimensional black rings associated with ‘pinched’ black holes and Myers-Perry black holes.

Black theology in South Africa – A theology of human dignity and black identity

Directory of Open Access Journals (Sweden)

Timothy van Aarde

2016-08-01

Full Text Available Black theology in South Africa is still relevant 20 years after the apartheid regime ended. It is a theology that gave to Black South Africans human dignity and a black identity. Black theology in South Africa confronted the imbalances of power and abusive power structures through an affirmation of human dignity and the uniqueness of the identity of black people. The biblical narrative of the Exodus is a definitive narrative in American black theology and liberation theology in overcoming oppression understood as political victimisation. Black theology in South Africa is not primarily about power and economics but also about the rediscovery of human dignity and black identity and to a lesser extent about victimisation. A third generation of black theology in South Africa will gain impetus through a rediscovery of human dignity and identity as its core values instead of a Black American liberation theology of victimisation or a Marxist liberation theology of the eradication of all power or economic imbalances.

Black hole hair removal

International Nuclear Information System (INIS)

Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

2009-01-01

Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair - degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

Measuring the angular momentum of supermassive black holes

CERN Document Server

Brenneman, Laura

2013-01-01

Measuring the spins of supermassive black holes (SMBHs) in active galactic nuclei (AGN) can inform us about the relative role of gas accretion vs. mergers in recent epochs of the life of the host galaxy and its AGN. Recent advances in theory and observation have enabled spin measurements for a handful of SMBHs thus far, but this science is still very much in its infancy. Herein, I discuss how and why we seek to measure black hole spin in AGN, using recent results from long X-ray observing campaigns on three radio-quiet AGN (MCG-6-30-15, NGC 3783 and Fairall 9) to illustrate this process and its caveats. I then present our current knowledge of the distribution of SMBH spins in the local universe. I also address prospects for improving the accuracy, precision and quantity of these spin constraints in the next decade and beyond with instruments such as NuSTAR, Astro-H and a future generation large-area X-ray telescope.

Upon opening the black box of participatory design and finding it filled with ethics

NARCIS (Netherlands)

Steen, M.G.D.

2011-01-01

In this essay, I bring together Participatory Design's (PD) tradition of critical reflection on one's own practices, and Science and Technology Studies' focus on specific activities ('opening the black box'), in order to explore the ethics of PD. Three different forms of ethics—ethics-of-theother,

Digging Deeper: Observing Primordial Gravitational Waves below the Binary-Black-Hole-Produced Stochastic Background.

Science.gov (United States)

Regimbau, T; Evans, M; Christensen, N; Katsavounidis, E; Sathyaprakash, B; Vitale, S

2017-04-14

The merger rate of black hole binaries inferred from the detections in the first Advanced LIGO science run implies that a stochastic background produced by a cosmological population of mergers will likely mask the primordial gravitational wave background. Here we demonstrate that the next generation of ground-based detectors, such as the Einstein Telescope and Cosmic Explorer, will be able to observe binary black hole mergers throughout the Universe with sufficient efficiency that the confusion background can potentially be subtracted to observe the primordial background at the level of Ω_{GW}≃10^{-13} after 5 years of observation.

Engaging youth of color in applied science education and public health promotion

Science.gov (United States)

Sprague Martinez, Linda; Bowers, Edmond; Reich, Amanda J.; Ndulue, Uchenna J.; Le, Albert An; Peréa, Flavia C.

2016-03-01

Participation in inquiry-based science education, which focuses on student-constructed learning, has been linked to academic success. Whereas the benefits of this type of science education are evident, access to such high-quality science curriculum and programming is not equitable. Black and Latino students in particular have less access to supplementary science programming, and fewer opportunities to engage in inquiry-based education. This paper describes outcomes associated with an inquiry-based out-of-school time science education program, Nuestro Futuro: Applied Science Education to Engage Black and Latino Youth (NFASE), which sought to build the capacity of middle school students of color to 'think' like health scientists from diverse disciplinary perspectives. The program was designed with the intent of (1) improving student attitudes toward and motivation for science and (2) increasing active and engaged citizenship (AEC). NFASE students explored health inequity and the social determinants of health locally and engaged in developing health promotion, outreach and education efforts targeted to their peers, parents/families, and community. Interest in the program was high overall, but implementation was not without challenges. Although evaluation outcomes indicate that there were no statistically significant changes in science-related attitudes or motivation, students reported significant increases in neighborhood social connection, as well as overall AEC.

UH-60M Black Hawk Helicopter (UH-60M Black Hawk)

Science.gov (United States)

2016-12-01

Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-341 UH-60M Black Hawk Helicopter (UH-60M Black Hawk ) As of FY 2017 President’s Budget Defense...Acquisition Management Information Retrieval (DAMIR) March 21, 2016 18:25:45 UNCLASSIFIED UH-60M Black Hawk December 2015 SAR March 21, 2016 18...Operational Requirements Document OSD - Office of the Secretary of Defense O&S - Operating and Support PAUC - Program Acquisition Unit Cost UH-60M Black Hawk

C-Bag Consolidation: An Inventory and Safety Stock Analysis

Science.gov (United States)

2014-06-13

and vertical integration and it is responsible for all aspects of installation management for 187 Army installations. (Burbach, 2010) IMCOM has...chemical protective overgarment, two pair of footwear covers or one Green/Black Vinyle Overshoe, two pair of glove sets and two protective hoods...Air Force Base, Alabama: Air Force Logistics Managment Agency. Tietje, R. W. (2002). Embedded Case Study Methods: Integrating Quantitative and

Place-Based Learning: Interactive Learning and Net-Zero Design

Science.gov (United States)

Holser, Alec; Becker, Michael

2011-01-01

Food and conservation science curriculum, net-zero design and student-based building performance monitoring have come together in the unique and innovative new Music and Science Building for Oregon's Hood River Middle School. The school's Permaculture-based curriculum both informed the building design and was also transformed through the…

Black American and Nigerian Pentecostalism: A Black Religious ...

African Journals Online (AJOL)

Black American and Nigerian Pentecostalism: A Black Religious Schizophrenia, 1910-2010. ... in American and African Pentecostalism as is related to social crisis, the dislocation of masses brought on by economic deprivation, urbanization, the break up of traditional society and consequence loss of traditional values.

Black Tea

Science.gov (United States)

... mental alertness as well as learning, memory, and information processing skills. It is also used for treating headache; ... of carbamazepine. Since black tea contains caffeine, in theory taking black tea with carbamazepine might decrease the ...

Starchild Presents...StarChild: A Learning Center for Young Astronomers. Black Holes. An Information and Activity Booklet. Grades K-8, 1998-1999.

Science.gov (United States)

Truelove, Elizabeth; Dejoie, Joyce

The information provided in this booklet is meant to give the necessary background information so that the science of black holes can be taught confidently to elementary students. The featured activities can be used to engage and excite students about the topic of black holes in different disciplines and in a number of ways. Activities include:…

Using stochastic gradient boosting to infer stopover habitat selection and distribution of Hooded Cranes Grus monacha during spring migration in Lindian, Northeast China.

Science.gov (United States)

Cai, Tianlong; Huettmann, Falk; Guo, Yumin

2014-01-01

The Hooded Crane (Grus monacha) is a globally vulnerable species, and habitat loss is the primary cause of its decline. To date, little is known regarding the specific habitat needs, and stopover habitat selection in particular, of the Hooded Crane. In this study we used stochastic gradient boosting (TreeNet) to develop three specific habitat selection models for roosting, daytime resting, and feeding site selection. In addition, we used a geographic information system (GIS) combined with TreeNet to develop a species distribution model. We also generated a digital map of the relative occurrence index (ROI) of this species at daytime resting sites in the study area. Our study indicated that the water depth, distance to village, coverage of deciduous leaves, open water area, and density of plants were the major predictors of roosting site selection. For daytime resting site selection, the distance to wetland, distance to farmland, and distance to road were the primary predictors. For feeding site selection, the distance to road, quantity of food, plant coverage, distance to village, plant density, distance to wetland, and distance to river were contributing factors, and the distance to road and quantity of food were the most important predictors. The predictive map showed that there were two consistent multi-year daytime resting sites in our study area. Our field work in 2013 using systematic ground-truthing confirmed that this prediction was accurate. Based on this study, we suggest that Lindian plays an important role for migratory birds and that cultivation practices should be adjusted locally. Furthermore, public education programs to promote the concept of the harmonious coexistence of humans and cranes can help successfully protect this species in the long term and eventually lead to its delisting by the IUCN.

Using stochastic gradient boosting to infer stopover habitat selection and distribution of Hooded Cranes Grus monacha during spring migration in Lindian, Northeast China.

Directory of Open Access Journals (Sweden)

Tianlong Cai

Full Text Available The Hooded Crane (Grus monacha is a globally vulnerable species, and habitat loss is the primary cause of its decline. To date, little is known regarding the specific habitat needs, and stopover habitat selection in particular, of the Hooded Crane. In this study we used stochastic gradient boosting (TreeNet to develop three specific habitat selection models for roosting, daytime resting, and feeding site selection. In addition, we used a geographic information system (GIS combined with TreeNet to develop a species distribution model. We also generated a digital map of the relative occurrence index (ROI of this species at daytime resting sites in the study area. Our study indicated that the water depth, distance to village, coverage of deciduous leaves, open water area, and density of plants were the major predictors of roosting site selection. For daytime resting site selection, the distance to wetland, distance to farmland, and distance to road were the primary predictors. For feeding site selection, the distance to road, quantity of food, plant coverage, distance to village, plant density, distance to wetland, and distance to river were contributing factors, and the distance to road and quantity of food were the most important predictors. The predictive map showed that there were two consistent multi-year daytime resting sites in our study area. Our field work in 2013 using systematic ground-truthing confirmed that this prediction was accurate. Based on this study, we suggest that Lindian plays an important role for migratory birds and that cultivation practices should be adjusted locally. Furthermore, public education programs to promote the concept of the harmonious coexistence of humans and cranes can help successfully protect this species in the long term and eventually lead to its delisting by the IUCN.

Science at Hampton Normal and Agricultural Institute, 1868-1893

Science.gov (United States)

Tucker, Linda Bart

Science had a variety of uses at Hampton Normal and Agricultural Institute, a private, missionary school supported by northern whites and Virginia's black land grant school from 1872 to 1920. Samuel Chapman Armstrong, principal for the first twenty-five years (1868-1893), advocated not classical but scientific studies, primarily as applied science to improve lives and "civilize" blacks and Indians. Agriculture and mechanics were practiced in Hampton's industries, where students worked their way through school. They were organized for production rather than instruction, though Armstrong claimed that labor had a moral value and that practical experience was valuable learning. In contrast to works by James D. Anderson and Donald Spivey, this study stresses the pragmatic, business purposes of Hampton's industries rather than any ideological agenda. Problems with providing specialized facilities, apparatus, and teachers made it difficult for Hampton to provide rigorous, graded science instruction. Students learned of practical applications of science in agricultural lectures and in such classes as physiology. However, the curriculum was designed for teacher training, using broad, elementary science for general knowledge, to train minds, and to make adult remedial language lessons more effective. Not surprisingly, very few graduates pursued careers which required more than general science studies. Besides the utilitarian and disciplinary purposes, Hampton used science to discourage superstitious ideas in religion. Armstrong also argued for racially distinctive education for blacks and Indians on the basis of scientific ideas about cultural evolution and inheritance of the experience of past generations. In practice, however, Hampton teachers adapted mainstream tools and methods of instruction. Not all teachers shared Armstrong's racial views, and several demonstrated concern for students, confidence in their ability, and professional interest in advancing them as

Student achievement in science: A longitudinal look at individual and school differences

Science.gov (United States)

Martinez, Alina

The importance of science in today's technological society necessitates continued attention to students' experiences in science and specifically their achievement in science. There is a need to look at gender and race/ethnicity simultaneously when studying students' experiences in science and to explore factors related to higher achievement among students. Using data from the Longitudinal Study of American Youth, this study contributes to existing literature on student achievement in science by simultaneously exploring the effects of race/ethnicity and gender. Capitalizing on the availability of yearly science achievement scores, I present trajectories of student achievement from 7th to 12th grade. This study also includes an exploration of school effects. Overall, student achievement in science increases from 7th to 12th grade, although some leveling is seen in later grades. Growth in achievement differs by both gender and race/ethnicity, but racial/ethnic differences are larger than gender differences. Hispanic, Black, Asian, and White males score higher, on average, throughout the secondary grades than their female counterparts. Achievement scores of Asian students are consistently higher than White students, who in turn score higher than Hispanic and finally Black students. Both background and science-related factors help explain variation in achievement status and growth in achievement. Parental education is positively associated with achievement status among all groups except Black students for whom there is no effect of parental education. Science related resources in the home are positively associated with student achievement and the effect of these resources increases in later grades. Student achievement in science is also positively related to student course taking and attitude toward science. Furthermore, both the negative effect of viewing science as a male domain, which exists for males and females, and the positive effect of parental support for

Black holes are warm

International Nuclear Information System (INIS)

Ravndal, F.

1978-01-01

Applying Einstein's theory of gravitation to black holes and their interactions with their surroundings leads to the conclusion that the sum of the surface areas of several black holes can never become less. This is shown to be analogous to entropy in thermodynamics, and the term entropy is also thus applied to black holes. Continuing, expressions are found for the temperature of a black hole and its luminosity. Thermal radiation is shown to lead to explosion of the black hole. Numerical examples are discussed involving the temperature, the mass, the luminosity and the lifetime of black mini-holes. It is pointed out that no explosions corresponding to the prediction have been observed. It is also shown that the principle of conservation of leptons and baryons is broken by hot black holes, but that this need not be a problem. The related concept of instantons is cited. It is thought that understanding of thermal radiation from black holes may be important for the development of a quantified gravitation theory. (JIW)

How Often do Giant Black Holes Become Hyperactive?

Science.gov (United States)

2010-12-01

for field galaxies -- as some results have hinted -- but then decreased more rapidly, at some point the cluster fraction would be about equal to the field fraction. This may explain what is being seen in the local Universe. The Milky Way contains a supermassive black hole known as Sagittarius A* (Sgr A*, for short). Even though astronomers have witnessed some activity from Sgr A* using Chandra and other telescopes over the years, it has been at a very low level. If the Milky Way follows the trends seen in the ChaMP survey, Sgr A* should be about a billion times brighter in X-rays for roughly 1% of the remaining lifetime of the Sun. Such activity is likely to have been much more common in the distant past. If Sgr A* did become an AGN it wouldn't be a threat to life here on Earth, but it would give a spectacular show at X-ray and radio wavelengths. However, any planets that are much closer to the center of the Galaxy, or directly in the line of fire, would receive large and potentially damaging amounts of radiation. These results were published in the November 10th issue of the Astrophysical Journal. Other co-authors on the paper were Scott Anderson of the University of Washington, Anca Constantin from James Madison University, Tom Aldcroft and Dong-Woo Kim from Harvard-Smithsonian Center for Astrophysics and Wayne Barkhouse from the University of North Dakota. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass. More information, including images and other multimedia, can be found at: http://chandra.harvard.edu and http://chandra.nasa.gov

Is It because I'm Black? A Black Female Research Experience

Science.gov (United States)

Maylor, Uvanney

2009-01-01

This article examines what it means to be a Black female researcher in contemporary Britain. Drawing on Black feminist theory and critical race theory (CRT), this article seeks to highlight some of the experiences and challenges that Black female researchers face when undertaking research, particularly research that has diversity, equality or…

The stable problem of the black-hole connected region in the Schwarzschild black hole

OpenAIRE

Tian, Guihua

2005-01-01

The stability of the Schwarzschild black hole is studied. Using the Painlev\\'{e} coordinate, our region can be defined as the black-hole-connected region(r>2m, see text) of the Schwarzschild black hole or the white-hole-connected region(r>2m, see text) of the Schwarzschild black hole. We study the stable problems of the black-hole-connected region. The conclusions are: (1) in the black-hole-connected region, the initially regular perturbation fields must have real frequency or complex frequen...

Black hole how an idea abandoned by Newtonians, hated by Einstein, and gambled on by Hawking became loved

CERN Document Server

Bartusiak, Marcia

2015-01-01

For more than half a century, physicists and astronomers engaged in heated dispute over the possibility of black holes in the universe. The weirdly alien notion of a space-time abyss from which nothing escapes-not even light-seemed to confound all logic. This engrossing book tells the story of the fierce black hole debates and the contributions of Einstein and Hawking and other leading thinkers who completely altered our view of the universe. Renowned science writer Marcia Bartusiak shows how the black hole helped revive Einstein's greatest achievement, the general theory of relativity, after decades during which it had been pushed into the shadows. Not until astronomers discovered such surprising new phenomena as neutron stars and black holes did the once-sedate universe transform into an Einsteinian cosmos, filled with sources of titanic energy that can be understood only in the light of relativity. This book celebrates the hundredth anniversary of general relativity, uncovers how the black hole really got ...

Quantum aspects of black holes

CERN Document Server

2015-01-01

Beginning with an overview of the theory of black holes by the editor, this book presents a collection of ten chapters by leading physicists dealing with the variety of quantum mechanical and quantum gravitational effects pertinent to black holes. The contributions address topics such as Hawking radiation, the thermodynamics of black holes, the information paradox and firewalls, Monsters, primordial black holes, self-gravitating Bose-Einstein condensates, the formation of small black holes in high energetic collisions of particles, minimal length effects in black holes and small black holes at the Large Hadron Collider. Viewed as a whole the collection provides stimulating reading for researchers and graduate students seeking a summary of the quantum features of black holes.

Black holes and beyond

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-02-01

Belief in the existence of black holes is the ultimate act of faith for a physicist. First suggested by the English clergyman John Michell in the year 1784, the gravitational pull of a black hole is so strong that nothing - not even light - can escape. Gravity might be the weakest of the fundamental forces but black-hole physics is not for the faint-hearted. Black holes present obvious problems for would-be observers because they cannot, by definition, be seen with conventional telescopes - although before the end of the decade gravitational-wave detectors should be able to study collisions between black holes. Until then astronomers can only infer the existence of a black hole from its gravitational influence on other matter, or from the X-rays emitted by gas and dust as they are dragged into the black hole. However, once this material passes through the 'event horizon' that surrounds the black hole, we will never see it again - not even with X-ray specs. Despite these observational problems, most physicists and astronomers believe that black holes do exist. Small black holes a few kilometres across are thought to form when stars weighing more than about two solar masses collapse under the weight of their own gravity, while supermassive black holes weighing millions of solar masses appear to be present at the centre of most galaxies. Moreover, some brave physicists have proposed ways to make black holes - or at least event horizons - in the laboratory. The basic idea behind these 'artificial black holes' is not to compress a large amount of mass into a small volume, but to reduce the speed of light in a moving medium to less than the speed of the medium and so create an event horizon. The parallels with real black holes are not exact but the experiments could shed new light on a variety of phenomena. The first challenge, however, is to get money for the research. One year on from a high-profile meeting on artificial black holes in London, for

Octavia Butler and Virginia Hamilton: Black Women Writers and Science Fiction.

Science.gov (United States)

Hampton, Gregory Jerome; Brooks, Wanda M.

2003-01-01

Notes that African American literature has always had science fiction elements in its focus on narratives of the alienated and marginalized "other." Contends that Octavia Butler and Virginia Hamilton are two African American writers of science fiction who examine the connections between the stories of a culture and the genre of science…

Complicated Contradictions Amid Black Feminism and Millennial Black Women Teachers Creating Curriculum for Black Girls

Science.gov (United States)

Nyachae, Tiffany M.

2016-01-01

Millennial Black women teachers wrestle with two simultaneous burdens: disrupting the racist and sexist status quo of schooling through curriculum, and employing tactics to survive school politics among their majority White women colleagues. This article describes how the "Sisters of Promise" (SOP) curriculum aligned with Black feminism…

Chandra Discovers Light Echo from the Milky Way's Black Hole

Science.gov (United States)

2007-01-01

Like cold case investigators, astronomers have used NASA's Chandra X-ray Observatory to uncover evidence of a powerful outburst from the giant black hole at the Milky Way's center. A light echo was produced when X-ray light generated by gas falling into the Milky Way's supermassive black hole, known as Sagittarius A* (pronounced "A-star"), was reflected off gas clouds near the black hole. While the primary X-rays from the outburst would have reached Earth about 50 years ago, the reflected X-rays took a longer path and arrived in time to be recorded by Chandra. Variability in Chandra Images of Light Echo Variability in Chandra Images of Light Echo "This dramatic event happened before we had satellites in space that could detect it," said Michael Muno of the California Institute of Technology in Pasadena. "So, it's remarkable that we can use Chandra to dig into the past and see this monster black hole's capacity for destruction." Previously, scientists have used Chandra to directly detect smaller and more recent outbursts from the black hole. This latest outburst revealed by the X-ray echo was about 1,000 times brighter and lasted well over 1,000 times longer than any of the recent outbursts observed by Chandra. Theory predicts that an outburst from Sagittarius A* would cause X-ray emission from the clouds to vary in both intensity and shape. Muno and his team found these changes for the first time, thus ruling out other interpretations. The latest results corroborate other independent, but indirect, evidence for light echoes generated by the black hole in the more distant past. Illustrations of Light Echo Illustrations of Light Echo Scientists have long known that Sagittarius A*, with a mass of about 3 million suns, lurked at the center for Milky Way. However, the black hole is incredibly faint at all wavelengths, especially in X-rays. "This faintness implies that stars and gas rarely get close enough to the black hole to be in any danger," said co-author Frederick

Rotating black holes at future colliders. III. Determination of black hole evolution

International Nuclear Information System (INIS)

Ida, Daisuke; Oda, Kin-ya; Park, Seong Chan

2006-01-01

TeV scale gravity scenario predicts that the black hole production dominates over all other interactions above the scale and that the Large Hadron Collider will be a black hole factory. Such higher-dimensional black holes mainly decay into the standard model fields via the Hawking radiation whose spectrum can be computed from the greybody factor. Here we complete the series of our work by showing the greybody factors and the resultant spectra for the brane-localized spinor and vector field emissions for arbitrary frequencies. Combining these results with the previous works, we determine the complete radiation spectra and the subsequent time evolution of the black hole. We find that, for a typical event, well more than half a black hole mass is emitted when the hole is still highly rotating, confirming our previous claim that it is important to take into account the angular momentum of black holes

Investigating Supermassive Black Hole Spin at Different Redshift

Science.gov (United States)

Sinanan-Singh, Jasmine

2018-01-01

Supermassive black hole (SMBH) spin encodes vital information about the history of SMBH growth. High spins indicate a history of growth through large mass accretion events, which spin-up the black hole; Intermediate spins indicate a history of galactic mergers, which don't tend to systemcatically spin-up or spin-down black holes; low spins are attributed to successive, small accretion events with random orientations. Examining spin over different redshifts will help us understand the relative growth of SMBHs by mergers or accretion over cosmic time, an important part of understanding how SMBHs and their host galaxies co-evolved over time. To study spin, we compute the Fe K alpha emission line from the X-ray spectra of AGN sources in the Chandra-COSMOS Legacy Survey. We stack rest frame AGN spectra to improve the signal-to-noise ratio since the photon counts are low for individual spectra, and then average the spectra using an unwieghted mean. Our method is derived from Corral et al. (2008). We test our method on the two brightest sources in the COSMOS Survey and compute the rest frame average Fe K alpha emission line for different redshift bins. The SAO REU program is funded by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant AST-1659473, and by the Smithsonian Institution.

BlackBerry For Dummies

CERN Document Server

Kao, Robert

2010-01-01

Get the most juice out of your BlackBerry handheld!. Feature-rich and complex, the BlackBerry is the number one smartphone in the corporate world is among the most popular handhelds for business users. This new and updated edition includes all the latest and greatest information on new and current BlackBerry mobile devices. Covering a range of valuable how-to topics, this helpful guide explores the BlackBerry's most useful features, techniques for getting the most out of your BlackBerry, and practical information about power usage.: Covers all aspects of the number one smartphone in the corpor

The use of paleo-imaging and microbiological testing in the analysis of antique cultural material: multislice tomography, and microbial analysis of the Trogir Cathedral cope hood depicting St. Martin and a beggar.

Science.gov (United States)

Cavka, Mislav; Petaros, Anja; Kavur, Lovro; Skrlin, Jasenka; Mlinaric Missoni, Emilija; Jankovic, Ivor; Brkljacic, Boris

2013-01-01

Paleoradiology is the study of biological and other materials from archeological settings through the use of various medical imaging techniques. Although it is most often used in the scientific study of ancient human remains, it can also be used to study metals, ceramics, paper, and clothes. The aim of this study was to test two paleoimaging techniques (MSCT and mammography) in the analysis of an important Croatian liturgical vestment: the hood of a bishop's cope from St. Lawrence's Treasury in Trogir depicting St. Martin and a beggar. To ensure a safe environment for scientists participating in the analysis, a preliminary microbiological analysis was performed, which contributed to the database of microbiological flora found on Croatian archeological remains and relics studied to date. Due to a great amount of metal filaments, the paleoradiological analysis did not produce satisfactory results. However, a digitally enhanced image clearly showed fine metal embroidery of the hood that was not so easily perceived by naked eye. This article argues in favor of expanding paleoradiological studies on materials other than human remains and also of publishing unsatisfactory results, as important lessons for future development of techniques and methods to analyze ancient remains and seek answers about human historical and cultural heritage.

Hawking radiation and entropy of a black hole in Lovelock-Born-Infeld gravity from the quantum tunneling approach

Science.gov (United States)

Li, Gu-Qiang

2017-04-01

The tunneling radiation of particles from black holes in Lovelock-Born-Infeld (LBI) gravity is studied by using the Parikh-Wilczek (PW) method, and the emission rate of a particle is calculated. It is shown that the emission spectrum deviates from the purely thermal spectrum but is consistent with an underlying unitary theory. Compared to the conventional tunneling rate related to the increment of black hole entropy, the entropy of the black hole in LBI gravity is obtained. The entropy does not obey the area law unless all the Lovelock coefficients equal zero, but it satisfies the first law of thermodynamics and is in accordance with earlier results. It is distinctly shown that the PW tunneling framework is related to the thermodynamic laws of the black hole. Supported by Guangdong Natural Science Foundation (2016A030307051, 2015A030313789)

Black Hole Area Quantization rule from Black Hole Mass Fluctuations

OpenAIRE

Schiffer, Marcelo

2016-01-01

We calculate the black hole mass distribution function that follows from the random emission of quanta by Hawking radiation and with this function we calculate the black hole mass fluctuation. From a complete different perspective we regard the black hole as quantum mechanical system with a quantized event horizon area and transition probabilities among the various energy levels and then calculate the mass dispersion. It turns out that there is a perfect agreement between the statistical and ...

Framing black boys: parent, teacher, and student narratives of the academic lives of black boys.

Science.gov (United States)

Rowley, Stephanie J; Ross, Latisha; Lozada, Fantasy T; Williams, Amber; Gale, Adrian; Kurtz-Costes, Beth

2014-01-01

The discourse on Black boys tends to suggest that Black boys are in complete peril. We begin with evidence that Black boys are excelling in certain contexts (i.e., in certain states, in certain schools, and in certain courses). We then discuss the ways in which the narratives used by parents, teachers, and Black boys themselves may serve to further reinforce views that Black boys are beyond hope. Research on Black parents suggests that they tend to view their sons as vulnerable and have lower expectations for sons than for daughters. Studies of teachers show that they tend to view Black boys as unteachable, as social problems, and as scary. Research on Black boys shows that they are sometimes complicit in supporting these narratives by engaging in negative or ste reotypical behavior. We also include recent research that includes counter-narratives of Black boys. We end with suggestions for future research.

Analysis of aluminium by atomic absorption spectrometry and analysis of thorium and uranium by alpha spectrometry in the black sand of Egypt

International Nuclear Information System (INIS)

Hannachi, Dhouha; Mathlouthi, Nadia

2008-01-01

Throughout the period of our project of end of study carried out in the Center ; main road Sciences and Nuclear Engineering's CNSTN in one is tallied took one Egypt black sand simple with an aim has of knowing the activities of the existing radio elements and especially Uranium and Thorium. In the same mining, we try to take another Egypt black sand simple an aim has knowing the mass of aluminum by using a techniques in Atomique Absorption Spectrophotometer. After the radio chemical and Spectrometry analysis of the black sand sample we found the results following: - Egypt black sand is contains isotopes of Uranium such as 234 U and 238 U; - The Egypt black sand is contains isotopes of Thorium such as 230 Th and 232 Th. - L' Aluminum is a major. (Author)

VINTE ANOS DA LEI ROBIN HOOD: UM BALANÇO DA PROTEÇÃO DO PATRIMÔNIO CULTURAL EM MINAS GERAIS (Dossiê: Gestão, Educação e Patrimônio Cultural

Directory of Open Access Journals (Sweden)

Helaine Nolasco Queiroz

2015-06-01

Full Text Available Resumo: O presente texto busca discutir o impacto causado na preservação do patrimônio cultural mineiro pela lei Robin Hood ou Lei do ICMS que, em 2015, completa vinte anos de vigência. Ele partiu das reflexões apresentadas no XIX Simpósio Regional da ANPUH, realizado em Juiz de Fora em 2014, cujo tema foi Profissão historiador: formação e mercado de trabalho, e mostrou-se digno de maior divulgação e publicaçao pela atualidade e relevância do tema. O objetivo é conjecturar sobre as mudanças trazidas pela lei na preservação do patrimônio de Minas Gerais tanto no órgão fiscalizador da preservação no estado quanto nos municípios que aderiram à lei e, ainda, na atuação profissional dos que se dedicam à área. Palavras-chave: Patrimônio cultural, ICMS cultural, Lei Robin Hood, Minas Gerais, IEPHA/MG   Abstract: This text intends to discuss the impact caused in the Cultural Heritage of Minas Gerais (Brazil by the Robin Wood Law, or Low of the ICMS, that completes 20 years of existence in 2015. The idea received an explanation in the XIX Regional Simposion of ANPUH that took place in Juiz de Fora (Minas Gerais, Brazil in 2014. The theme of the simposium was The profession of historian: superior education and work marketing and it showed the actuality and the relevance of deeper discusstions about the subject. The purpose of the article is to reflect about the changes brought by the law in the cultural heritage preservation in Minas Gerais, in the organ that inspects the aplication of the law, in the cities that gain the ressourcers of the law and in the actuation of the professionals of the area.Keywords: Cultural Heritage, ICMS Law, Robin Hood Law, Minas Gerais (Brazil, IEPHARecebido em: 20/05/2015 – Aceito em 23/06/2015

The Black Family as Educator.

Science.gov (United States)

Wallace, Joan

The black family is the primary socializing agent of the black child and, thus, the primary educator. The culture of blacks in America, in which the child is steeped, is unique, complex and rich-the result of a convergence and fusion of African, American, and European influences. In its education of the black child, the black family must deal,…

Monopole Black Hole Skyrmions

OpenAIRE

Moss, Ian G; Shiiki, N; Winstanley, E

2000-01-01

Charged black hole solutions with pion hair are discussed. These can be\\ud used to study monopole black hole catalysis of proton decay.\\ud There also exist\\ud multi-black hole skyrmion solutions with BPS monopole behaviour.

Effects of clay on fat necrosis and carcass characteristics in Japanese Black steers.

Science.gov (United States)

Oka, Akio; Iwamoto, Eiji; Tatsuda, Ken

2015-10-01

Twenty 10-month-old Japanese Black steers were used to evaluate the effects of clay on fat necrosis and carcass characteristics. Ten steers (Clay group) were fed the clay (50 g/day) during 10-30 months of age. The other 10 steers (Control group) were not fed it. There was no significant difference in body weight or average daily gain between the two groups (P > 0.05). The occurrence of fat necrotic mass in the Clay group (30%) was lower (P Clay group was smaller (P clay prevented the occurrence of fat necrosis and did not affect the carcass characteristics in Japanese Black steers. © 2015 Japanese Society of Animal Science.

Skyrmion black hole hair: Conservation of baryon number by black holes and observable manifestations

Energy Technology Data Exchange (ETDEWEB)

Dvali, Gia [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, 80333 München (Germany); Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, 80805 München (Germany); Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Gußmann, Alexander, E-mail: alexander.gussmann@physik.uni-muenchen.de [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, 80333 München (Germany)

2016-12-15

We show that the existence of black holes with classical skyrmion hair invalidates standard proofs that global charges, such as the baryon number, cannot be conserved by a black hole. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. We then perform a refined Gedankenexperiment by incorporating the new knowledge and show that no contradiction with conservation of baryon number takes place at any stage of black hole evolution. Our analysis also indicates no conflict between semi-classical black holes and the existence of baryonic gauge interaction arbitrarily-weaker than gravity. Next, we study classical cross sections of a minimally-coupled massless probe scalar field scattered by a skyrmion black hole. We investigate how the skyrmion hair manifests itself by comparing this cross section with the analogous cross section caused by a Schwarzschild black hole which has the same ADM mass as the skyrmion black hole. Here we find an order-one difference in the positions of the characteristic peaks in the cross sections. The peaks are shifted to smaller scattering angles when the skyrmion hair is present. This comes from the fact that the skyrmion hair changes the near horizon geometry of the black hole when compared to a Schwarzschild black hole with same ADM mass. We keep the study of this second aspect general so that the qualitative results which we obtain can also be applied to black holes with classical hair of different kind.

Historiography of the Epidemic of “Black Death” on the Territory of Juchid Ulus (1814–2016

Directory of Open Access Journals (Sweden)

T.F. Khaydarov

2017-03-01

Full Text Available Objective: to examine the main works and theories of foreign and domestic authors, which has considered the theme of “Black death” on the territory of the ulus of Jochi in 1814–2016. Research materials: at the present stage of development of historical science the way out from methodological crisis is the most pressing issue. As international experience shows, progress towards the knowledge of the past is only possible through interaction with other disciplines, such as genetics or biology. At the moment, the epidemic of “Black Death” is rightfully considered one of these research topics. This event was of great importance in the history. Raged for several hundreds of years and killed up to a third of the then population, the plague significantly changed the face of human societies, accelerated the transition to a new economic system, to the culture and philosophy of Modern times. However, until recently research on this topic mainly focused on studying either biology of the plague, or the study of reality emerged after the “Black Death”. In these circumstances, the transition to interdisciplinarity, which occurred in recent years in Western science, allowed not only more comprehensive approach to the study of this topic, but to expand the regions under study and to include among them, in the first instance, Northern Eurasia and its most important part – Juchid ulus. In general, Western historiography had not yet developed an unambiguous assessment of the “Black Death” in this region. This is partly due to lack of experience with written sources in the Tatar and Russian languages as well as due to not long period of work with archaeological sources. At the same time, domestic science has more than 200 years of experience in understanding of this problem, but it suffers from several disadvantages. Results and novelty of the research: on the basis of historiographical material, the article manages to conclude that despite a

Statistical black-hole thermodynamics

International Nuclear Information System (INIS)

Bekenstein, J.D.

1975-01-01

Traditional methods from statistical thermodynamics, with appropriate modifications, are used to study several problems in black-hole thermodynamics. Jaynes's maximum-uncertainty method for computing probabilities is used to show that the earlier-formulated generalized second law is respected in statistically averaged form in the process of spontaneous radiation by a Kerr black hole discovered by Hawking, and also in the case of a Schwarzschild hole immersed in a bath of black-body radiation, however cold. The generalized second law is used to motivate a maximum-entropy principle for determining the equilibrium probability distribution for a system containing a black hole. As an application we derive the distribution for the radiation in equilibrium with a Kerr hole (it is found to agree with what would be expected from Hawking's results) and the form of the associated distribution among Kerr black-hole solution states of definite mass. The same results are shown to follow from a statistical interpretation of the concept of black-hole entropy as the natural logarithm of the number of possible interior configurations that are compatible with the given exterior black-hole state. We also formulate a Jaynes-type maximum-uncertainty principle for black holes, and apply it to obtain the probability distribution among Kerr solution states for an isolated radiating Kerr hole

Faculty of health sciences, walter sisulu university: training doctors from and for rural South african communities.

Science.gov (United States)

Iputo, Jehu E

2008-10-01

Introduction The South African health system has disturbing inequalities, namely few black doctors, a wide divide between urban and rural sectors, and also between private and public services. Most medical training programs in the country consider only applicants with higher-grade preparation in mathematics and physical science, while most secondary schools in black communities have limited capacity to teach these subjects and offer them at standard grade level. The Faculty of Health Sciences at Walter Sisulu University (WSU) was established in 1985 to help address these inequities and to produce physicians capable of providing quality health care in rural South African communities. Intervention Access to the physician training program was broadened by admitting students who obtained at least Grade C (60%) in mathematics and physical science at standard grade, and who demonstrated appropriate personal attributes. An innovative curriculum, combining problem-based learning with community-based education (PBL/CBE) in small tutorial group settings, was also adopted. This approach was aimed at educating and graduating a broader cohort of students, while training future doctors to identify, analyze, and treat health problems in the rural South African context. Outcomes To date, 745 doctors (72% black Africans) have graduated from the program, and 511 students (83% black Africans) are currently enrolled. After the PBL/CBE curriculum was adopted, the attrition rate for black students dropped from 23% to 80%, and the proportion of students graduating within the minimum period rose from 55% to >70%. Many graduates are still completing internships or post-graduate training, but preliminary research shows that 36% percent of graduates practice in small towns and rural settings. Further research is underway to evaluate the impact of their training on health services in rural Eastern Cape Province and elsewhere in South Africa. Conclusions The WSU program increased access to

Retelling the educational pathways of Black women physicists: Stories of experiencing and overcoming obstacles in life

Science.gov (United States)

Mensah, Felicia

This is an empirical study on the underrepresentation of people of color in scientific careers. Grounded in critical race theory, the paper examines the lived experiences of six Black women physicists and addresses obstacles faced in their career paths and strategies used to overcome these obstacles. Data for this study were collected through semi-structured interviews and coded for emergent themes. The findings reveal that college recruitment and funding were fundamental for these women to choose physics over other STEM fields. In addition, Black women experience unique challenges of socialization in STEM, particularly by exclusion of study groups. We suggest physics departments provide a more inclusive environment to support Black women in science. CAPES, the Fulbright Program, Comissão Fulbright Brasil, and the Office of Diversity at Teachers College, Columbia University.

Black holes without firewalls

Science.gov (United States)

Larjo, Klaus; Lowe, David A.; Thorlacius, Larus

2013-05-01

The postulates of black hole complementarity do not imply a firewall for infalling observers at a black hole horizon. The dynamics of the stretched horizon, that scrambles and reemits information, determines whether infalling observers experience anything out of the ordinary when entering a large black hole. In particular, there is no firewall if the stretched horizon degrees of freedom retain information for a time of the order of the black hole scrambling time.

Fear of a Black femme: The existential conundrum of embodying a Black femme identity while being a professor of Black, queer, and feminist studies.

Science.gov (United States)

Story, Kaila Adia

2017-10-02

Although a Black femme identity has been defined and embodied by many as an identity with Black feminist roots and revolutionary potentials, Black femmes are still rendered hypervisible and invisible through racist and heteronormative politics. Similarly, embodying a Black femme identity as a professor in academia often engenders these same pretenses of hypervisibility and invisibility. This essay explores what this existential conundrum has been for me as both a Black femme and professor of Black queer and feminist studies, while illuminating the mix of forces within academia that have attempted to stifle my chosen sexual identity and gendered performance.

Exploring Jets from a Supermassive Black Hole

Science.gov (United States)

Kohler, Susanna

2018-06-01

collaborators observations span the enormous radial distance of a thousand to a billion times the radius of the black hole, or about 54 light-days to more than a million light-years.Scale for ChangeThe width of the jet as a function of radial distance from the black hole, for NGC 4261 (red) compared to the few other jets from nearby supermassive black holes that weve measured. NGC 4261s jets transition from parabolic to conical at around 10,000 times the radius of the black hole (RS). [Nakahara et al. 2018]The authors observations of NGC 4261s jets indicate that a transition occurs at 10,000 times the radius of the black hole (thats a little over a light-year from the black hole). At this point, the jets structures change from parabolic (becoming more tightly beamed) to conical (expanding freely). Around the same location, Nakahara and collaborators also see the radiation profile of one of the jets change, suggesting the physical conditions in the jets transition here as well.This is the first time weve been able to examine jet width this closely for both of the jets emitted from a supermassive black hole. The fact that the structure changes at the same distance for both jets indicates that the shape of these powerful streams is likely governed by global properties of the environment surrounding the galaxys nucleus, or properties of the jets themselves, rather than by a local condition.The authors next hope to pin down velocities inside NGC 4261s jets to determine where the jets accelerate and decelerate. This nearby powerhouse is clearly going to be a useful laboratory in the future, helping to unveil the secrets of more distant, feeding monsters.BonusCurious what these hungry supermassive black holes look like? Check out this artists imagining of NGC 4261, which shows how it feeds from a large, swirling accretion disk and emits fast-moving, collimated jets. [Original video credit to Dana Berry, Space Telescope Science Institute]CitationSatomi Nakahara et al 2018 ApJ 854 148

Black Lives Matter of Black Identity Extremist? : The FBI, Black Activists and the Struggle for Victimhood

NARCIS (Netherlands)

Mutsaers, Paul

2017-01-01

The question 'who is the victim?' is an important social directive that shapes the struggles for victimhood in which Black Lives Matters, U.S. police forces and their various (counter)publics are currently engaging. This column begins with a controversial FBI report on so-called Black Identity

Einstein-Gauss-Bonnet metrics: black holes, black strings and a staticity theorem

International Nuclear Information System (INIS)

Bogdanos, C.; Charmousis, C.; Gouteraux, B.; Zegers, R.

2009-01-01

We find the general solution of the 6-dimensional Einstein-Gauss-Bonnet equations in a large class of space and time-dependent warped geometries. Several distinct families of solutions are found, some of which include black string metrics, space and time-dependent solutions and black holes with exotic horizons. Among these, some are shown to verify a Birkhoff type staticity theorem, although here, the usual assumption of maximal symmetry on the horizon is relaxed, allowing exotic horizon geometries. We provide explicit examples of such static exotic black holes, including ones whose horizon geometry is that of a Bergman space. We find that the situation is very different from higher-dimensional general relativity, where Einstein spaces are admissible black hole horizons and the associated black hole potential is not even affected. In Einstein-Gauss-Bonnet theory, on the contrary, the non-trivial Weyl tensor of such exotic horizons is exposed to the bulk dynamics through the higher order Gauss-Bonnet term, severely constraining the allowed horizon geometries and adding a novel charge-like parameter to the black hole potential. The latter is related to the Euler characteristic of the four-dimensional horizon and provides, in some cases, additional black hole horizons.

Accreting Black Holes

OpenAIRE

Begelman, Mitchell C.

2014-01-01

I outline the theory of accretion onto black holes, and its application to observed phenomena such as X-ray binaries, active galactic nuclei, tidal disruption events, and gamma-ray bursts. The dynamics as well as radiative signatures of black hole accretion depend on interactions between the relatively simple black-hole spacetime and complex radiation, plasma and magnetohydrodynamical processes in the surrounding gas. I will show how transient accretion processes could provide clues to these ...

Naked black holes

International Nuclear Information System (INIS)

Horowitz, G.T.; Ross, S.F.

1997-01-01

It is shown that there are large static black holes for which all curvature invariants are small near the event horizon, yet any object which falls in experiences enormous tidal forces outside the horizon. These black holes are charged and near extremality, and exist in a wide class of theories including string theory. The implications for cosmic censorship and the black hole information puzzle are discussed. copyright 1997 The American Physical Society

Haul-out behavior of harbor seals (Phoca vitulina in Hood Canal, Washington.

Directory of Open Access Journals (Sweden)

Josh M London

Full Text Available The goal of this study was to model haul-out behavior of harbor seals (Phoca vitulina in the Hood Canal region of Washington State with respect to changes in physiological, environmental, and temporal covariates. Previous research has provided a solid understanding of seal haul-out behavior. Here, we expand on that work using a generalized linear mixed model (GLMM with temporal autocorrelation and a large dataset. Our dataset included behavioral haul-out records from archival and VHF radio tag deployments on 25 individual seals representing 61,430 seal hours. A novel application for increased computational efficiency allowed us to examine this large dataset with a GLMM that appropriately accounts for temporal autocorellation. We found significant relationships with the covariates hour of day, day of year, minutes from high tide and year. Additionally, there was a significant effect of the interaction term hour of day : day of year. This interaction term demonstrated that seals are more likely to haul out during nighttime hours in August and September, but then switch to predominantly daylight haul-out patterns in October and November. We attribute this change in behavior to an effect of human disturbance levels. This study also examined a unique ecological event to determine the role of increased killer whale (Orcinus orca predation on haul-out behavior. In 2003 and 2005 these harbor seals were exposed to unprecedented levels of killer whale predation and results show an overall increase in haul-out probability after exposure to killer whales. The outcome of this study will be integral to understanding any changes in population abundance as a result of increased killer whale predation.

Legitimizing Blacks in Philosophy

Directory of Open Access Journals (Sweden)

Jameliah Shorter-Bourhanou

2017-12-01

Full Text Available In its efforts toward improving diversity, the discipline of philosophy has tended to focus on increasing the number of black philosophers. One crucial issue that has received less attention is the extent to which black philosophers are delegitimized in the discipline because their philosophical contributions challenge the status quo. A systematic problem that bars black philosophers from equal and full participation, this delegitimization precludes the emergence of genuine diversity and reveals the importance of interrogating broader attitudes toward black philosophical contributions. In this essay, I argue for radical systematic changes to disciplinary hallmarks of professionalization such as pedagogy, mentoring, publishing, and hiring practices with the aim of legitimizing black philosophers and their contributions.

HUBBLE provides multiple views of how to feed a black hole

Science.gov (United States)

1998-05-01

fuel from a devoured galaxy, it may be oblivious to the rest of the galaxy and the collision," said Ethan Schreier of the Space Telescope Science Institute, Baltimore, MD. Schreier and an international team of co-investigators used Hubble's Near Infrared Camera and Multi-Object Spectrometer to probe deeper into the galaxy's mysterious heart than anyone has before. The hot gas disk viewed by Hubble investigators is perpendicular to the galaxy's outer dust belt, while the black hole's own internal accretion disk of superhot gas falling into it is tilted approximately diagonally to these axes. "We have found a complicated situation of a disk within a disk within a disk, all pointing in different directions," Schreier said. It is not clear if the black hole was always present in the host galaxy or belonged to the spiral galaxy that fell into the core, or if it is the product of the merger of a pair of smaller black holes that lived in the two once-separate galaxies. Having an active galaxy just 10 million light-years away from Earth rather than hundreds of millions or billions of light-years distant offers astronomers a unique laboratory for understanding the elusive details of the behavior of supermassive black holes as fueled by galaxy collisions. "Though Hubble has seen hot gas disks around black holes in other galaxies, the infrared camera has for the first time allowed us to peer at this relatively nearby, very active, but obscured black hole region," Schreier added. The team of astronomers is awaiting further Hubble data to continue its study of the disk, as well as ground-based spectroscopic observations to measure the velocity of entrapped material around the black hole. This will allow the astronomers to better calculate the black hole's mass. The current results are scheduled to appear in the June 1, 1998 issue of Astrophysical Journal Letters. Images and further information related to these results are available on the Internet at the following URLs: http

From inside the black box: Teacher perceptions of science instruction at the elementary level

Science.gov (United States)

Ferrini, Cynthia D.

Science education reform projects aimed at elementary school children arose in the 1960's. The most prevalent of these reforms utilized the inquiry, or hands-on, science method. Billions of dollars have been invested in these reforms. Yet, reports indicate that science is not being taught at the level one might expect in elementary schools. This research was an analysis of the problems and concerns teachers at one school district faced as they tried to implement and sustain elementary inquiry science instruction. The district chosen was a large suburban district in the Western United States. The population was ninety percent Caucasian with a slightly more ethnically diverse school population. This district was chosen because it had an elementary science program for over twenty years and had received national acclaim for that program. The district had a stable and homogeneous staff there was a low administrator and teacher turnover rate and the elementary teaching population was ninety percent Caucasian and ninety percent female. Interviews with administrators and teachers were conducted. Data were collected from focus groups of teachers and science partners. Observations of elementary science classroom instruction and professional development sessions were made. Results of this research indicated that one important key to elementary science reform rests in the hands of teachers. Once the door to the classroom is closed, the teacher can decide to teach or not to teach science. The findings of this research illustrate that teachers hold ideas about science and science instruction that are antithetical to some tenets of inquiry science. Until these ideas are addressed it will be difficult, if not impossible, to implement a systemic elementary inquiry science program. This study demonstrates that professional development for elementary teachers in science needs to change from a focus on the mechanical usage of individual units to a focus on teacher expectations for

Black holes are hot

International Nuclear Information System (INIS)

Gibbons, G.

1976-01-01

Recent work, which has been investigating the use of the concept of entropy with respect to gravitating systems, black holes and the universe as a whole, is discussed. The resulting theory of black holes assigns a finite temperature to them -about 10 -7 K for ordinary black holes of stellar mass -which is in complete agreement with thermodynamical concepts. It is also shown that black holes must continuously emit particles just like ordinary bodies which have a certain temperature. (U.K.)

Journal of Fundamental and Applied Sciences - Vol 10, No 2S (2018)

African Journals Online (AJOL)

Technology requirement for Halal quality control · EMAIL FREE FULL TEXT ... fibre reinforced plastic, aluminium alloy and alloy steel for car hood application for ... gravitational search algorithm in feature selection for automatic classification of ...

Black swans, wicked problems, and science during crises

Science.gov (United States)

Machlis, G.E.; McNutt, M.K.

2011-01-01

Oceanic resources face challenges that are significant and widespread, including (but not limited to) overharvesting, climate change, selected stock collapse, coral reef decline, species extinction, pollution, and more. These challenges are the focus of much ocean science, which is helping to inform policy and guide management actions. The steady growth of research results and the emergence of new research needs have been systematically reviewed through periodic assessments, such as those of the Intergovernmental Oceanographic Commission (Valdés et al., 2010).

Intermediate-Mass Black Holes

Science.gov (United States)

Miller, M. Coleman; Colbert, E. J. M.

2004-01-01

The mathematical simplicity of black holes, combined with their links to some of the most energetic events in the universe, means that black holes are key objects for fundamental physics and astrophysics. Until recently, it was generally believed that black holes in nature appear in two broad mass ranges: stellar-mass (M~3 20 M⊙), which are produced by the core collapse of massive stars, and supermassive (M~106 1010 M⊙), which are found in the centers of galaxies and are produced by a still uncertain combination of processes. In the last few years, however, evidence has accumulated for an intermediate-mass class of black holes, with M~102 104 M⊙. If such objects exist they have important implications for the dynamics of stellar clusters, the formation of supermassive black holes, and the production and detection of gravitational waves. We review the evidence for intermediate-mass black holes and discuss future observational and theoretical work that will help clarify numerous outstanding questions about these objects.

Advancement of High Temperature Black Liquor Gasification Technology

Energy Technology Data Exchange (ETDEWEB)

Craig Brown; Ingvar Landalv; Ragnar Stare; Jerry Yuan; Nikolai DeMartini; Nasser Ashgriz

2008-03-31

design, specification and procurement of facility upgrades. Chemrec AB is also operating a pressurized, O2-blown gasifier pilot facility in Piteaa, Sweden. There was an exchange of knowledge with the pressurized projects including utilization of the experimental results from facilities in Piteaa, Sweden. Resources at the Georgia Tech Research Corporation (GTRC, a.k.a., the Institute of Paper Science and Technology) were employed primarily to conduct the fundamental investigations on scaling and plugging mechanisms and characterization of green liquor dregs. The project also tapped GTRC expertise in the development of the critical underlying black liquor gasification rate subroutines employed in the CFD code. The actual CFD code development and application was undertaken by Process Simulation, Ltd (PSL) and Simulent, Ltd. PSL focused on the overall integrated gasifier CFD code, while Simulent focused on modeling the black liquor nozzle and description of the black liquor spray. For nozzle development and testing Chemrec collaborated with ETC (Energy Technology Centre) in Piteae utilizing their test facility for nozzle spray investigation. GTI (Gas Technology Institute), Des Plains, IL supported the team with advanced gas analysis equipment during the gasifier test period in June 2005.

Imagine the Universe! The Anatomy of Black Holes. Probing the Structure & Evolution of the Cosmos. An Information and Activity Booklet. Grades 9-12, 1998-1999.

Science.gov (United States)

Whitlock, Laura A.; Granger, Kara C.; Mahon, Jane D.

The information provided in this booklet is meant to give the necessary background information so that the science of black holes can be taught confidently to secondary students. The featured activities can be used to engage and excite students about the topic of black holes in different disciplines and in a number of ways. Activities include: (1)…

The Effect of Black Peers on Black Test Scores

Science.gov (United States)

Armor, David J.; Duck, Stephanie

2007-01-01

Recent studies have used increasingly complex methodologies to estimate the effect of peer characteristics--race, poverty, and ability--on student achievement. A paper by Hanushek, Kain, and Rivkin using Texas state testing data has received particularly wide attention because it found a large negative effect of school percent black on black math…

Gravitational waves from binary supermassive black holes missing in pulsar observations.

Science.gov (United States)

Shannon, R M; Ravi, V; Lentati, L T; Lasky, P D; Hobbs, G; Kerr, M; Manchester, R N; Coles, W A; Levin, Y; Bailes, M; Bhat, N D R; Burke-Spolaor, S; Dai, S; Keith, M J; Osłowski, S; Reardon, D J; van Straten, W; Toomey, L; Wang, J-B; Wen, L; Wyithe, J S B; Zhu, X-J

2015-09-25

Gravitational waves are expected to be radiated by supermassive black hole binaries formed during galaxy mergers. A stochastic superposition of gravitational waves from all such binary systems would modulate the arrival times of pulses from radio pulsars. Using observations of millisecond pulsars obtained with the Parkes radio telescope, we constrained the characteristic amplitude of this background, A(c,yr), to be gravitational waves. Copyright © 2015, American Association for the Advancement of Science.

Black hole multiplicity at particle colliders (Do black holes radiate mainly on the brane?)

International Nuclear Information System (INIS)

Cavaglia, Marco

2003-01-01

If gravity becomes strong at the TeV scale, we may have the chance to produce black holes at particle colliders. In this Letter we revisit some phenomenological signatures of black hole production in TeV-gravity theories. We show that the bulk-to-brane ratio of black hole energy loss during the Hawking evaporation phase depends crucially on the black hole greybody factors and on the particle degrees of freedom. Since the greybody factors have not yet been calculated in the literature, and the particle content at trans-Planckian energies is not known, it is premature to claim that the black hole emits mainly on the brane. We also revisit the decay time and the multiplicity of the decay products of black hole evaporation. We give general formulae for black hole decay time and multiplicity. We find that the number of particles produced during the evaporation phase may be significantly lower than the average multiplicity which has been used in the past literature

Understanding the Black Aesthetic Experience.

Science.gov (United States)

Curtis, Marvin V.

1988-01-01

Discussing the importance of the Black aesthetic experience, Curtis examines Black cultural heritage and participatory style, the spiritual, and the creation and recreation of Black music. Advocating multicultural music education in teacher training, he suggests that Black music be studied for its value and contribution to society. Lists five ways…

Black Writers' Views of America.

Science.gov (United States)

Hairston, Loyle

1979-01-01

This article argues that the stagnation, pessimism, and self-pity evident in recent Black writing results in part from the alienation of Black writers from the mainstream of Black life, and in part from the illusions that they share with other Blacks who have embraced the American value system. (Author/EB)

USSTRIDE program is associated with competitive Black and Latino student applicants to medical school.

Science.gov (United States)

Campbell, Kendall M; Berne-Anderson, Thesla; Wang, Aihua; Dormeus, Guy; Rodríguez, José E

2014-01-01

We compared MCAT scores, grade point averages (GPAs), and medical school acceptance rates of Black and Latino students in an outreach program called Undergraduate Science Students Together Reaching Instructional Diversity and Excellence (USSTRIDE) to non-USSTRIDE students. We hypothesized that Black and Latino participants in USSTRIDE had higher acceptance rates to medical school, higher MCAT scores, and college GPAs when compared to other Black and Latino medical school applicants from our institution. The academic performance (GPAs and MCAT scores) and acceptance and matriculation rate data on all Black and Latino Florida State University applicants to any medical school from 2008 to 2012 were collected from the AIS/AMCAS database and separated into two comparison groups (USSTRIDE vs. Non-USSTRIDE). Independent sample T-tests and chi-square analysis, Cohen's D test, and odds ratios were determined. Average science GPA was 3.47 for USSTRIDE students (n=55) and 3.45 for non-USSTRIDE students (n=137, p=0.68, d=0.0652). Average cumulative GPA was 3.57 for USSTRIDE students and 3.54 for non-USSTRIDE students (p=0.45, d=0.121). Average MCAT score was 23 for USSTRIDE students and 25 for non-USSTRIDE students (p=0.02, d=0.378). Twenty-three percent of accepted USSTRIDE students and 29% of accepted non-USSTRIDE students had multiple acceptances (p=0.483, OR 1.38, 95% CI 0.52-3.88). Forty-nine percent of non-USSTRIDE students and 75% of USSTRIDE students matriculated in medical school (p=0.001, OR 3.13 95% CI 1.51-6.74). About 78.6% of USSTRIDE students matriculated at FSU's medical school compared to 36.2% of non-USSTRIDE students (pLatino students to our medical school. This finding is true for other medical schools as USSTRIDE students are as likely as non-USSTRIDE students to have multiple acceptances.

String-Corrected Black Holes

Energy Technology Data Exchange (ETDEWEB)

Hubeny, V.

2005-01-12

We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect--the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive. The magnitude of this effect is related to the size of the compactification manifold.

Doing Science with eLISA: Astrophysics and Cosmology in the Millihertz Regime

Science.gov (United States)

Amaro, Seoane, Pau; Aoudia, Sofiane; Babak, Stanislav; Binetruy, Pierre; Berti, Amanuele; Bohe, Alejandro; Caprini, Chiara; Colpi, Monica; Cornish, Neil J.; Danzmann, Karsten;

BlackMax: A black-hole event generator with rotation, recoil, split branes, and brane tension

International Nuclear Information System (INIS)

Dai Dechang; Starkman, Glenn; Stojkovic, Dejan; Issever, Cigdem; Tseng, Jeff; Rizvi, Eram

2008-01-01

We present a comprehensive black-hole event generator, BlackMax, which simulates the experimental signatures of microscopic and Planckian black-hole production and evolution at the LHC in the context of brane world models with low-scale quantum gravity. The generator is based on phenomenologically realistic models free of serious problems that plague low-scale gravity, thus offering more realistic predictions for hadron-hadron colliders. The generator includes all of the black-hole gray-body factors known to date and incorporates the effects of black-hole rotation, splitting between the fermions, nonzero brane tension, and black-hole recoil due to Hawking radiation (although not all simultaneously). The generator can be interfaced with Herwig and Pythia. The main code can be downloaded from http://www-pnp.physics.ox.ac.uk/~issever/BlackMax/blackmax.html.

Internal structure of black holes

International Nuclear Information System (INIS)

Cvetic, Mirjam

2013-01-01

Full text: We review recent progress that sheds light on the internal structure of general black holes. We first summarize properties of general multi-charged rotating black holes both in four and five dimensions. We show that the asymptotic boundary conditions of these general asymptotically flat black holes can be modified such that a conformal symmetry emerges. These subtracted geometries preserve the thermodynamic properties of the original black holes and are of the Lifshitz type, thus describing 'a black hole in the asymptotically conical box'. Recent efforts employ solution generating techniques to construct interpolating geometries between the original black hole and their subtracted geometries. Upon lift to one dimension higher, these geometries lift to AdS 3 times a sphere, and thus provide a microscopic interpretation of the black hole entropy in terms of dual two-dimensional conformal field theory. (author)

Partnership Opportunities In Earth System Science Education Between Historically Black and Historically White Universities: Elizabeth City State University and the University of New Hampshire

Science.gov (United States)

Williams, J. E.; Hayden, L. B.; Wake, C. P.; Varner, R. K.; Graham, K.; Rock, B. N.; Hale, S.; Hurtt, G. C.; Porter, W.; Blackmon, R.; Bryce, J. G.; Branch, B. D.; Johnson, J. E.

2009-12-01

Federal efforts to promote the participation of underrepresented students in the science, technology, engineering and mathematics disciplines (STEM) in higher education have been in effect over several decades. The Science and Engineering Equal Opportunities Act of 1980 aimed to create equal opportunity in the STEM disciplines by promoting and broadening the participation of underrepresented talent in science and engineering. Since that time, federal agencies such as the National Science Foundation, NOAA and NASA, scientific organizations such as the American Geophysical Union, and other organizations such as the Educational Testing Service have created programs, diversity plans and cutting edge reports designed to further explicate the need to broaden the participation of underrepresented student talent in these disciplines. Despite increases in the degrees awarded to underrepresented students in the STEM disciplines, enhancing diversity in these disciplines continues to remain a significant challenge. This paper describes a strategic approach to this challenge via the development of a collaborative partnership model between two universities: the historically black Elizabeth City State University (ESCU) and the historically white University of New Hampshire (UNH). The alliance, built on a mutually-agreed upon set of partnership principles, strives to enhance opportunities for underrepresented students to pursue careers in STEM disciplines, specifically those in Earth system science and remote sensing. In examining the partnership, six promising practices that help advance its success come to the forefront. These practices include institutional commitment and faculty engagement, mutual respect and shared time commitment, identifying engaged leadership, engaging critical change agents, initiating difficult dialogues, and preparing for growth and evolution. Outcomes of the partnership to date include the successful submission and funding of four collaborative

Black supernovae and black holes in non-local gravity

Energy Technology Data Exchange (ETDEWEB)

Bambi, Cosimo [Center for Field Theory and Particle Physics and Department of Physics, Fudan University,200433 Shanghai (China); Theoretical Astrophysics, Eberhard-Karls Universität Tübingen,72076 Tübingen (Germany); Malafarina, Daniele [Department of Physics, Nazarbayev University,010000 Astana (Kazakhstan); Modesto, Leonardo [Center for Field Theory and Particle Physics and Department of Physics, Fudan University,200433 Shanghai (China)

2016-04-22

In a previous paper, we studied the interior solution of a collapsing body in a non-local theory of gravity super-renormalizable at the quantum level. We found that the classical singularity is replaced by a bounce, after which the body starts expanding. A black hole, strictly speaking, never forms. The gravitational collapse does not create an event horizon but only an apparent one for a finite time. In this paper, we solve the equations of motion assuming that the exterior solution is static. With such an assumption, we are able to reconstruct the solution in the whole spacetime, namely in both the exterior and interior regions. Now the gravitational collapse creates an event horizon in a finite comoving time, but the central singularity is approached in an infinite time. We argue that these black holes should be unstable, providing a link between the scenarios with and without black holes. Indeed, we find a non catastrophic ghost-instability of the metric in the exterior region. Interestingly, under certain conditions, the lifetime of our black holes exactly scales as the Hawking evaporation time.

German science and black racism--roots of the Nazi Holocaust.

Science.gov (United States)

Haas, François

2008-02-01

The Nazi's cornerstone precept of "racial hygiene" gave birth to their policy of "racial cleansing" that led to the murders of millions. It was developed by German physicians and scientists in the late 19th century and is rooted in the period's Social Darwinism that placed blacks at the bottom of the racial ladder. This program was first manifested in the near-extermination of the African Herero people during the German colonial period. After WWI, the fear among the German populace that occupying African troops and their Afro-German children would lead to "bastardization" of the German people formed a unifying racial principle that the Nazis exploited. They extended this mind-set to a variety of "unworthy" groups, leading to the physician-administered racial Nuremberg laws, the Sterilization laws, the secret sterilization of Afro-Germans, and the German euthanasia program. This culminated in the extermination camps.

Chandra Sees Wealth Of Black Holes In Star-Forming Galaxies

Science.gov (United States)

2001-06-01

NASA's Chandra X-ray Observatory has found new populations of suspected mid-mass black holes in several starburst galaxies, where stars form and explode at an unusually high rate. Although a few of these objects had been found previously, this is the first time they have been detected in such large numbers and could help explain their relationship to star formation and the production of even more massive black holes. At the 198th meeting of the American Astronomical Society in Pasadena, California, three independent teams of scientists reported finding dozens of X-ray sources in galaxies aglow with star formation. These X-ray objects appear point-like and are ten to a thousand times more luminous in X-rays than similar sources found in our Milky Way and the M81 galaxy. "Chandra gives us the ability to study the populations of individual bright X-ray sources in nearby galaxies in extraordinary detail," said Andreas Zezas, lead author from the Harvard-Smithsonian Center for Astrophysics team that observed The Antennae, a pair of colliding galaxies, and M82, a well-known starburst galaxy. "This allows us to build on earlier detections of these objects and better understand their relationship to starburst galaxies." Antennae-True Color Image True Color Image of Antennae Credit: NASA/SAO/G.Fabbiano et al. Press Image and Caption Kimberly Weaver, of NASA's Goddard Space Flight Center in Greenbelt, MD, lead scientist of the team that studied the starburst galaxy NGC 253, discussed the importance of the unusual concentration of these very luminous X-ray sources near the center of that galaxy. Four sources, which are tens to thousands of times more massive than the Sun, are located within 3,000 light years of the galaxy core. "This may imply that these black holes are gravitating toward the center of the galaxy where they could coalesce to form a single supermassive black hole," Weaver suggested. "It could be that this starburst galaxy is transforming itself into a quasar

Black Sea aerosols

International Nuclear Information System (INIS)

Hacisalihoglu, G.; Eliyakut, F.; Anwari, M.A.; Ataman, O.Y.; Balkas, T.I.; Tuncel, G.; Olmez, I.

1991-01-01

Shipboard, high volume air particulate samples were collected from the Black Sea atmosphere and analyzed by instrumental neutron activation analysis, atomic absorption spectrophotometry and ion chromatography for about 40 elements and ions. Concentrations of elements in the eastern and western parts of the Black Sea are different at the 95% confidence level, with lower concentrations in the eastern Black Sea. Back-trajectories and concentrations of elements in trajectory groups show that Europe accounts for more than 70% of the anthropogenic elements in the atmosphere. The average sulfate concentration was 7 μg/m 3 , which is comparable with rural sulfate levels in western Europe. Fluxes of elements from the atmosphere to the Black Sea are in good agreement with the results of similar flux calculations for other regions

New Directions for Black Women?

Science.gov (United States)

McGuigan, Dorothy, Ed.

1978-01-01

This collection of papers deals with various aspects of the black female experience in America. "The Black Woman in Transition" discusses the effects of sexism and racism on black women with particular reference to employment and education; it is noted that black women, in comparison with other groups in society, suffer a proportionately higher…

Black-spot poison ivy.

Science.gov (United States)

Schram, Sarah E; Willey, Andrea; Lee, Peter K; Bohjanen, Kimberly A; Warshaw, Erin M

2008-01-01

In black-spot poison ivy dermatitis, a black lacquerlike substance forms on the skin when poison ivy resin is exposed to air. Although the Toxicodendron group of plants is estimated to be the most common cause of allergic contact dermatitis in the United States, black-spot poison ivy dermatitis is relatively rare.

What is black hole?

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. What is black hole? Possible end phase of a star: A star is a massive, luminous ball of plasma having continuous nuclear burning. Star exhausts nuclear fuel →. White Dwarf, Neutron Star, Black Hole. Black hole's gravitational field is so powerful that even ...

Genocide and Black Ecology

Science.gov (United States)

Sinnette, Calvin H.

1972-01-01

Contends that the survival of black people is in serious jeopardy as is evidenced in contemporary discussions on the worldwide plight of black people, and that an exhaustive study of the problem in its many dimensions is seriously lacking; the moral and ethical issues of genocide require examination from a black perspective. (JW)

Quantum effects in black holes

International Nuclear Information System (INIS)

Frolov, V.P.

1979-01-01

A strict definition of black holes is presented and some properties with regard to their mass are enumerated. The Hawking quantum effect - the effect of vacuum instability in the black hole gravitational field, as a result of shich the black hole radiates as a heated body is analyzed. It is shown that in order to obtain results on the black hole radiation it is sufficient to predetermine the in-vacuum state at a time moment in the past, when the collapsing body has a large size, and its gravitational field can be neglected. The causes and the place of particle production by the black hole, and also the space-time inside the black hole, are considered

Carbon black vs. black carbon and other airborne materials containing elemental carbon: Physical and chemical distinctions

International Nuclear Information System (INIS)

Long, Christopher M.; Nascarella, Marc A.; Valberg, Peter A.

2013-01-01

Airborne particles containing elemental carbon (EC) are currently at the forefront of scientific and regulatory scrutiny, including black carbon, carbon black, and engineered carbon-based nanomaterials, e.g., carbon nanotubes, fullerenes, and graphene. Scientists and regulators sometimes group these EC-containing particles together, for example, interchangeably using the terms carbon black and black carbon despite one being a manufactured product with well-controlled properties and the other being an undesired, incomplete-combustion byproduct with diverse properties. In this critical review, we synthesize information on the contrasting properties of EC-containing particles in order to highlight significant differences that can affect hazard potential. We demonstrate why carbon black should not be considered a model particle representative of either combustion soots or engineered carbon-based nanomaterials. Overall, scientific studies need to distinguish these highly different EC-containing particles with care and precision so as to forestall unwarranted extrapolation of properties, hazard potential, and study conclusions from one material to another. -- Highlights: •Major classes of elemental carbon-containing particles have distinct properties. •Despite similar names, carbon black should not be confused with black carbon. •Carbon black is distinguished by a high EC content and well-controlled properties. •Black carbon particles are characterized by their heterogenous properties. •Carbon black is not a model particle representative of engineered nanomaterials. -- This review demonstrates the significant physical and chemical distinctions between elemental carbon-containing particles e.g., carbon black, black carbon, and engineered nanomaterials

Examining African self-consciousness and Black racial identity as predictors of Black men's psychological well-being.

Science.gov (United States)

Pierre, Martin R; Mahalik, James R

2005-02-01

This study investigated African self-consciousness and Black racial identity as predictors of psychological distress and self-esteem for Black men. One hundred thirty Black men from a college and community sample completed the African Self-Consciousness Scale, the Racial Identity Attitude Scale-B, the Symptom Checklist 90-Revised, and the Coopersmith Self-Esteem Inventory. Canonical correlation analysis found 2 significant roots with the 1st root indicating that Black men whose attitudes reflected Preencounter and Immersion racial identity attitudes and who do not resist against anti-African/Black forces reported greater psychological distress and less esteem. Results from the 2nd root suggested that Black men whose attitudes reflect greater Internalization racial identity attitudes, greater resistance to anti-African/Black forces, and less identification with Blacks reported greater self-esteem. ((c) 2005 APA, all rights reserved).

Dark Energy, Dark Matter and Science with Constellation-X

Science.gov (United States)

Cardiff, Ann Hornschemeier

2005-01-01

Constellation-X, with more than 100 times the collecting area of any previous spectroscopic mission operating in the 0.25-40 keV bandpass, will enable highthroughput, high spectral resolution studies of sources ranging from the most luminous accreting supermassive black holes in the Universe to the disks around young stars where planets form. This talk will review the updated Constellation-X science case, released in booklet form during summer 2005. The science areas where Constellation-X will have major impact include the exploration of the space-time geometry of black holes spanning nine orders of magnitude in mass and the nature of the dark energy and dark matter which govern the expansion and ultimate fate of the Universe. Constellation-X will also explore processes referred to as "cosmic feedback" whereby mechanical energy, radiation, and chemical elements from star formation and black holes are returned to interstellar and intergalactic medium, profoundly affecting the development of structure in the Universe, and will also probe all the important life cycles of matter, from stellar and planetary birth to stellar death via supernova to stellar endpoints in the form of accreting binaries and supernova remnants. This talk will touch upon all these areas, with particular emphasis on Constellation-X's role in the study of Dark Energy.

The angry black woman: the impact of pejorative stereotypes on psychotherapy with black women.

Science.gov (United States)

Ashley, Wendy

2014-01-01

In the aftermath of slavery and the resulting social, economic, and political effects, Black women have become the victims of negative stereotyping in mainstream American culture. Such stereotypes include the myth of the angry Black woman that characterizes these women as aggressive, ill tempered, illogical, overbearing, hostile, and ignorant without provocation. Symptoms presented by Black women during mental health treatment may reinforce this myth. However, many of the negative characteristics of the angry Black woman developed in response to external stressors and historical factors. Black women also have a unique experience with and expressions of anger that shape the presenting symptoms interpreted by the mental health clinician. This myth and corresponding negative stereotypes significantly affect Black women intrapsychically, interpersonally, and are likely to influence the efficacy of mental health treatment. Understanding and treatment of Black women in a mental health context should be influenced by the cultural norms and sociopolitical dynamics affecting these clients. Successful mental health treatment requires cultural competence and clinicians who are well prepared to navigate the inherent complexities of culture with clients. Awareness of the angry Black woman mythology, including its genesis, manifestations, and the unique experiences of Black women, may raise the standards of cultural competence for clinicians and provide more successful treatment outcomes in working with this population. A case example illustrates the assiduity essential to practicing in a culturally competent manner. A client is presented from a traditional psychotherapeutic perspective and then viewed through a lens that integrates psychotherapeutic practice with conscious awareness of the mythology and stereotypes impacting Black women. Implications for culturally relevant practice are discussed.

Over spinning a black hole?

Energy Technology Data Exchange (ETDEWEB)

Bouhmadi-Lopez, Mariam; Cardoso, Vitor; Nerozzi, Andrea; Rocha, Jorge V, E-mail: mariam.bouhmadi@ist.utl.pt, E-mail: vitor.cardoso@ist.utl.pt, E-mail: andrea.nerozzi@ist.utl.pt, E-mail: jorge.v.rocha@ist.utl.pt [CENTRA, Department de Fisica, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049 Lisboa (Portugal)

2011-09-22

A possible process to destroy a black hole consists on throwing point particles with sufficiently large angular momentum into the black hole. In the case of Kerr black holes, it was shown by Wald that particles with dangerously large angular momentum are simply not captured by the hole, and thus the event horizon is not destroyed. Here we reconsider this gedanken experiment for black holes in higher dimensions. We show that this particular way of destroying a black hole does not succeed and that Cosmic Censorship is preserved.

Adaptability of black walnut, black cherry, and Northern red oak to Northern California

Science.gov (United States)

Philip M. McDonald

1987-01-01

When planted in sheltered sites in northern California, only 49% of black walnut (Juglans nigra L.) and 58% of black cherry (Prunus serotina Ehrh.) survived for 15 years, and 20% of northern red oak (Quercus rubra L.) survived for 10 years. The black walnut trees averaged 0.6 inches diameter at breast...

Black Holes in Higher Dimensions

Directory of Open Access Journals (Sweden)

Reall Harvey S.

2008-09-01

Full Text Available We review black-hole solutions of higher-dimensional vacuum gravity and higher-dimensional supergravity theories. The discussion of vacuum gravity is pedagogical, with detailed reviews of Myers–Perry solutions, black rings, and solution-generating techniques. We discuss black-hole solutions of maximal supergravity theories, including black holes in anti-de Sitter space. General results and open problems are discussed throughout.

Black hole decay as geodesic motion

International Nuclear Information System (INIS)

Gupta, Kumar S.; Sen, Siddhartha

2003-01-01

We show that a formalism for analyzing the near-horizon conformal symmetry of Schwarzschild black holes using a scalar field probe is capable of describing black hole decay. The equation governing black hole decay can be identified as the geodesic equation in the space of black hole masses. This provides a novel geometric interpretation for the decay of black holes. Moreover, this approach predicts a precise correction term to the usual expression for the decay rate of black holes

The Black Atlantic as reversal: A reappraisal of African and black theology

Directory of Open Access Journals (Sweden)

Hans Engdahl

2017-09-01

Full Text Available In this article, I will try to do three things. Firstly, pay attention to the notion of Black Atlantic as coined by Paul Gilroy, which in effect could signify a reversal of colonialism and slavery. Secondly, revisit the 1970s and the debate about the relevance of Black theology vis-à-vis African theology, using John Mbiti’s article ‘An African Views American Black Theology’ as entry point. Here, I will discuss contributions also made by Desmond Tutu and James Cone. Thirdly, starting with the premise that both theologies are relevant and soul mates today, which would (probably be confirmed by all the above mentioned at this point in time, an assessment of current voices will be made, that is, Tinyiko Maluleke and Vuyani Vellem on black and African ecclesiologies from a South African perspective, and Lawrence Burnley on the fate of the Black Church in the United States.

"Vraisemblance" and the Western Setting in Contemporary Science Fiction Film.

Science.gov (United States)

Roth, Lane

Analyzing the setting of six recent "blockbuster" films, this study outlines numerous instances of the Western's influence on several contemporary science fiction films, "Star Wars,""Battlestar Galactica,""Star Trek: The Motion Picture,""The Black Hole,""The Empire Strikes Back," and…

Black report up-date

International Nuclear Information System (INIS)

1988-12-01

In 1984, the Black Report published its results on the incidence of cancer and leukaemia in under 25-year olds in the village of Seascale and the surrounding area near the Sellafield nuclear reprocessing plant. Since then the pressure group core, as a result of their own independent research, has discovered ten additional cases of childhood cancer which should have been included in the Black Report and a Further two cases since the Black Report was written. This represents an additional 31% over the initial numbers considered and a review of the Black Report is sought. (UK)

JPRS Report, Science & Technology: Europe.

Science.gov (United States)

1992-04-21

body, Mercedes Benz for the first time used cold wire laser welding. A second laser application joined the roof to the side wall. Volvo is doing...assem- blies leave the hood production line daily. The reasons for using lasers are many. In the case of Mercedes Benz , styling was the decisive factor...and Salt Lake City, Utah (U.S.)—is looking around for other sales markets . Reichardt has found new cus- tomers: " Advertising agencies, universities

Lifshitz topological black holes

International Nuclear Information System (INIS)

Mann, R.B.

2009-01-01

I find a class of black hole solutions to a (3+1) dimensional theory gravity coupled to abelian gauge fields with negative cosmological constant that has been proposed as the dual theory to a Lifshitz theory describing critical phenomena in (2+1) dimensions. These black holes are all asymptotic to a Lifshitz fixed point geometry and depend on a single parameter that determines both their area (or size) and their charge. Most of the solutions are obtained numerically, but an exact solution is also obtained for a particular value of this parameter. The thermodynamic behaviour of large black holes is almost the same regardless of genus, but differs considerably for small black holes. Screening behaviour is exhibited in the dual theory for any genus, but the critical length at which it sets in is genus-dependent for small black holes.

Predictors of indoor fine particulate matter in infants' bedrooms in Denmark

DEFF Research Database (Denmark)

Raaschou-Nielsen, Ole; Sørensen, Mette; Hertel, Ole

2011-01-01

conducted 1122 measurements of fine PM (PM2.5 and black smoke) in the bedrooms of 389 infants and registered indoor activities and characteristics of the house. We used mixed models to identify and quantify associations between predictors and concentrations. Results The concentration of PM2.5 was 2.8 times....... Frying without a range hood was associated with a 32% (95% CI, 12–54%) higher PM2.5 concentration per time per day, whereas frying with use of a range hood did not increase the concentration in the infant’s bedroom. Use of a fireplace, stove, candles or vacuum-cleaner, interior rebuilding or renovation......, local traffic, inner city residence and cold season increased the fine PM concentration. Open windows decreased the PM2.5 concentration in homes with smokers but increased the concentration in non-smoking homes. Conclusions We identified several sources of fine PM in infants’ bedrooms...

Acceleration of black hole universe

Science.gov (United States)

Zhang, T. X.; Frederick, C.

2014-01-01

Recently, Zhang slightly modified the standard big bang theory and developed a new cosmological model called black hole universe, which is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, and cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This paper investigates acceleration of the black hole universe and provides an alternative explanation for the redshift and luminosity distance measurements of type Ia supernovae. The results indicate that the black hole universe accelerates its expansion when it accretes the ambient matter in an increasing rate. In other words, i.e., when the second-order derivative of the mass of the black hole universe with respect to the time is positive . For a constant deceleration parameter , we can perfectly explain the type Ia supernova measurements with the reduced chi-square to be very close to unity, χ red˜1.0012. The expansion and acceleration of black hole universe are driven by external energy.

Why Blue-Collar Blacks Help Less

OpenAIRE

Smith, Sandra Susan; Young, Kara Alexis

2013-01-01

Why are blue-collar blacks less likely to help jobseekers than jobholders from other ethnoracial groups or even than more affluent blacks? Drawing from in-depth, semi-structured interviews with 97 black and Latino workers at one large, public sector employer, we find that blue-collar black workers both helped less proactively and rejected more requests for assistance than did blue-collar Latino and white-collar black workers. We attribute blue-collar blacks’ more passive engagement to their...

Curvature invariant characterization of event horizons of four-dimensional black holes conformal to stationary black holes

Science.gov (United States)

McNutt, David D.

2017-11-01

We introduce three approaches to generate curvature invariants that transform covariantly under a conformal transformation of a four-dimensional spacetime. For any black hole conformally related to a stationary black hole, we show how a set of conformally covariant invariants can be combined to produce a conformally covariant invariant that detects the event horizon of the conformally related black hole. As an application we consider the rotating dynamical black holes conformally related to the Kerr-Newman-Unti-Tamburino-(anti)-de Sitter spacetimes and construct an invariant that detects the conformal Killing horizon along with a second invariant that detects the conformal stationary limit surface. In addition, we present necessary conditions for a dynamical black hole to be conformally related to a stationary black hole and apply these conditions to the ingoing Kerr-Vaidya and Vaidya black hole solutions to determine if they are conformally related to stationary black holes for particular choices of the mass function. While two of the three approaches cannot be generalized to higher dimensions, we discuss the existence of a conformally covariant invariant that will detect the event horizon for any higher dimensional black hole conformally related to a stationary black hole which admits at least two conformally covariant invariants, including all vacuum spacetimes.

New geometries for black hole horizons

Energy Technology Data Exchange (ETDEWEB)

Armas, Jay [Physique Théorique et Mathématique,Université Libre de Bruxelles and International Solvay Institutes, ULB-Campus Plaine CP231, B-1050 Brussels (Belgium); Blau, Matthias [Albert Einstein Center for Fundamental Physics, University of Bern,Sidlerstrasse 5, 3012 Bern (Switzerland)

2015-07-10

We construct several classes of worldvolume effective actions for black holes by integrating out spatial sections of the worldvolume geometry of asymptotically flat black branes. This provides a generalisation of the blackfold approach for higher-dimensional black holes and yields a map between different effective theories, which we exploit by obtaining new hydrodynamic and elastic transport coefficients via simple integrations. Using Euclidean minimal surfaces in order to decouple the fluid dynamics on different sections of the worldvolume, we obtain local effective theories for ultraspinning Myers-Perry branes and helicoidal black branes, described in terms of a stress-energy tensor, particle currents and non-trivial boost vectors. We then study in detail and present novel compact and non-compact geometries for black hole horizons in higher-dimensional asymptotically flat space-time. These include doubly-spinning black rings, black helicoids and helicoidal p-branes as well as helicoidal black rings and helicoidal black tori in D≥6.

Statistical mechanics of black holes

International Nuclear Information System (INIS)

Harms, B.; Leblanc, Y.

1992-01-01

We analyze the statistical mechanics of a gas of neutral and charged black holes. The microcanonical ensemble is the only possible approach to this system, and the equilibrium configuration is the one for which most of the energy is carried by a single black hole. Schwarzschild black holes are found to obey the statistical bootstrap condition. In all cases, the microcanonical temperature is identical to the Hawking temperature of the most massive black hole in the gas. U(1) charges in general break the bootstrap property. The problems of black-hole decay and of quantum coherence are also addressed

Few-layer black phosphorus nanoparticles.

Science.gov (United States)

Sofer, Zdenek; Bouša, Daniel; Luxa, Jan; Mazanek, Vlastimil; Pumera, Martin

2016-01-28

Herein, black phosphorus quantum dots and nanoparticles of a few layer thickness were prepared and characterized using STEM, AFM, dynamic light scattering, X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy and photoluminescence. Impact electrochemistry of the induvidual black phosphorus nanoparticles allows their size determination. The centrifugation of colloidal black phosphorus nanoparticles allowed separation of quantum dots with sizes up to 15 nm. These black phosphorus nanoparticles exhibit a large band gap and are expected to find a wide range of applications from semiconductors to biomolecule tags. The use of black phosphorus nanoparticles for vapour sensing was successfully demonstrated.

Black Holes Lead Galaxy Growth, New Research Shows

Science.gov (United States)

2009-01-01

Astronomers may have solved a cosmic chicken-and-egg problem -- the question of which formed first in the early Universe -- galaxies or the supermassive black holes seen at their cores. "It looks like the black holes came first. The evidence is piling up," said Chris Carilli, of the National Radio Astronomy Observatory (NRAO). Carilli outlined the conclusions from recent research done by an international team studying conditions in the first billion years of the Universe's history in a lecture presented to the American Astronomical Society's meeting in Long Beach, California. Gas in Distant Galaxy VLA image (right) of gas in young galaxy seen as it was when the Universe was only 870 million years old. CREDIT: NRAO/AUI/NSF, SDSS Full-size JPEG, 323 KB PDF file, 180 KB Galaxy image, no annotation, JPEG 21 KB Earlier studies of galaxies and their central black holes in the nearby Universe revealed an intriguing linkage between the masses of the black holes and of the central "bulges" of stars and gas in the galaxies. The ratio of the black hole and the bulge mass is nearly the same for a wide range of galactic sizes and ages. For central black holes from a few million to many billions of times the mass of our Sun, the black hole's mass is about one one-thousandth of the mass of the surrounding galactic bulge. "This constant ratio indicates that the black hole and the bulge affect each others' growth in some sort of interactive relationship," said Dominik Riechers, of Caltech. "The big question has been whether one grows before the other or if they grow together, maintaining their mass ratio throughout the entire process." In the past few years, scientists have used the National Science Foundation's Very Large Array radio telescope and the Plateau de Bure Interferometer in France to peer far back in the 13.7 billion-year history of the Universe, to the dawn of the first galaxies. "We finally have been able to measure black-hole and bulge masses in several galaxies seen

Regular black hole in three dimensions

OpenAIRE

Myung, Yun Soo; Yoon, Myungseok

2008-01-01

We find a new black hole in three dimensional anti-de Sitter space by introducing an anisotropic perfect fluid inspired by the noncommutative black hole. This is a regular black hole with two horizons. We compare thermodynamics of this black hole with that of non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy.

Visual thinking networking promotes long-term meaningful learning and achievement for 9th grade earth science students

Science.gov (United States)

Longo, Palma Joni

2001-12-01

An experimental and interview-based design was used to test the efficacy of visual thinking networking (VTN), a new generation of metacognitive learning strategies. Students constructed network diagrams using semantic and figural elements to represent knowledge relationships. The findings indicated the importance of using color in VTN strategies. The use of color promoted the encoding and reconstruction of earth science knowledge in memory and enhanced higher order thinking skills of problem solving. Fifty-six ninth grade earth science students (13--15 years of age) in a suburban school district outside New York City were randomly assigned to three classes with the same instructor. Five major positive findings emerged in the areas of problem solving achievement, organization of knowledge in memory, problem solving strategy dimensionality, conceptual understanding, and gender differences. A multi-covariate analysis was conducted on the pre-post gain scores of the AGI/NSTA Earth Science Examination (Part 1). Students who used the color VTN strategies had a significantly higher mean gain score on the problem solving criterion test items than students who used the black/white VTN (p = .003) and the writing strategies for learning science (p color VTN strategies: (1) significantly recalled more earth science knowledge than students who used the black/white VTN (p = .021) and the writing strategies (p color VTNs had a significantly higher mean number of conceptually accurate propositions than students who used the black/white VTN (p = .018) and the writing strategies (p = .010). Gender influenced the choice of VTN strategy. Females used significantly more color VTN strategies, while males used predominately black/white VTN strategies (p = .01). A neurocognitive model, the encoding activation theory of the anterior cingulate (ENACT-AC), is proposed as an explanation for these findings.

Boosted quantum black hole and black string in M-theory, and quantum correction to Gregory-Laflamme instability

Energy Technology Data Exchange (ETDEWEB)

Hyakutake, Yoshifumi [Faculty of Science, Ibaraki University,Bunkyo 2-1-1, Mito, Ibaraki, 310-8512 (Japan)

2015-09-11

We take into account higher derivative R{sup 4} corrections in M-theory and construct quantum black hole and black string solutions in 11 dimensions up to the next leading order. The quantum black string is stretching along the 11th direction and the Gregory-Laflamme instability is examined at the quantum level. Thermodynamics of the boosted quantum black hole and black string are also discussed. Especially we take the near horizon limit of the quantum black string and investigate its instability quantitatively.

Exchanges between the open Black Sea and its North West shelf

Science.gov (United States)

Shapiro, Georgy; Wobus, Fred; Zhou, Feng

2014-05-01

offshore flow over a large section of the shelf break. Due to the short duration of strong wind effects (4-7 days) the horizontal extent of cross-shelf-break exchanges is limited to the outer shelf. The effect of Ekman drift is confined to the upper layers. In contrast, eddies and meanders penetrate deep down to the bottom, but they are restricted laterally. During the strong wind events of April 15 - 22 and July 1 - 4, some 0.66×1012 and 0.44×1012 m3of water were removed from the northwestern shelf respectively. In comparison, the single long-lived Sevastopol Eddy generated a much larger offshore transfer of 2.84×1012 m3 over the period April 23 to June 30, which is equivalent to 102% of the volume of northwestern shelf waters. This result is consistent with the data obtained from satellite derived information (Shapiro et al, 2010). The open Black Sea is generally warmer and more saline than the northwest shelf. Hence the exchanges contribute to the increase in both salinity and temperature of shelf waters. Over the study period, salt exchanges increased the average density of the shelf waters by 0.67 kg m-3 and reduced the density contrast between the shelf and deep sea, while lateral heat exchanges reduced the density of the shelf waters by 0.16 kg m-3 and thus enhanced density contrast across the shelf break. This study was supported by the EU (via PERSEUS grant FP7-OCEAN-2011-287600 and MyOcean SPA.2011.1.5-01 grant 283367), Ministry of Science and Technology of China (Grant 2011CB409803), the Natural Science Foundation of China (Grant 41276031), Zhejiang Association for International Exchange of Personnel, and the University of Plymouth Marine Institute Innovation Fund. References Huthnance, J. M., 1995. Circulation, exchange and water masses at the ocean margin: the role of physical processes at the shelf edge, Prog Oceanogr, 35(4), 353-431, Ivanov L.I., Besiktepe S., Ozsoy E., 1997. In: E.Ozsoy and A.Mikaelyan (eds). Sensitivity to change: Black Sea , Baltic Sea

Stationary black holes: large D analysis

International Nuclear Information System (INIS)

Suzuki, Ryotaku; Tanabe, Kentaro

2015-01-01

We consider the effective theory of large D stationary black holes. By solving the Einstein equations with a cosmological constant using the 1/D expansion in near zone of the black hole we obtain the effective equation for the stationary black hole. The effective equation describes the Myers-Perry black hole, bumpy black holes and, possibly, the black ring solution as its solutions. In this effective theory the black hole is represented as an embedded membrane in the background, e.g., Minkowski or Anti-de Sitter spacetime and its mean curvature is given by the surface gravity redshifted by the background gravitational field and the local Lorentz boost. The local Lorentz boost property of the effective equation is observed also in the metric itself. In fact we show that the leading order metric of the Einstein equation in the 1/D expansion is generically regarded as a Lorentz boosted Schwarzschild black hole. We apply this Lorentz boost property of the stationary black hole solution to solve perturbation equations. As a result we obtain an analytic formula for quasinormal modes of the singly rotating Myers-Perry black hole in the 1/D expansion.

Black branes as piezoelectrics.

Science.gov (United States)

Armas, Jay; Gath, Jakob; Obers, Niels A

2012-12-14

We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six.

Accuracy of binary black hole waveform models for aligned-spin binaries

Science.gov (United States)

Kumar, Prayush; Chu, Tony; Fong, Heather; Pfeiffer, Harald P.; Boyle, Michael; Hemberger, Daniel A.; Kidder, Lawrence E.; Scheel, Mark A.; Szilagyi, Bela

2016-05-01

Coalescing binary black holes are among the primary science targets for second generation ground-based gravitational wave detectors. Reliable gravitational waveform models are central to detection of such systems and subsequent parameter estimation. This paper performs a comprehensive analysis of the accuracy of recent waveform models for binary black holes with aligned spins, utilizing a new set of 84 high-accuracy numerical relativity simulations. Our analysis covers comparable mass binaries (mass-ratio 1 ≤q ≤3 ), and samples independently both black hole spins up to a dimensionless spin magnitude of 0.9 for equal-mass binaries and 0.85 for unequal mass binaries. Furthermore, we focus on the high-mass regime (total mass ≳50 M⊙ ). The two most recent waveform models considered (PhenomD and SEOBNRv2) both perform very well for signal detection, losing less than 0.5% of the recoverable signal-to-noise ratio ρ , except that SEOBNRv2's efficiency drops slightly for both black hole spins aligned at large magnitude. For parameter estimation, modeling inaccuracies of the SEOBNRv2 model are found to be smaller than systematic uncertainties for moderately strong GW events up to roughly ρ ≲15 . PhenomD's modeling errors are found to be smaller than SEOBNRv2's, and are generally irrelevant for ρ ≲20 . Both models' accuracy deteriorates with increased mass ratio, and when at least one black hole spin is large and aligned. The SEOBNRv2 model shows a pronounced disagreement with the numerical relativity simulation in the merger phase, for unequal masses and simultaneously both black hole spins very large and aligned. Two older waveform models (PhenomC and SEOBNRv1) are found to be distinctly less accurate than the more recent PhenomD and SEOBNRv2 models. Finally, we quantify the bias expected from all four waveform models during parameter estimation for several recovered binary parameters: chirp mass, mass ratio, and effective spin.

Biodegradable black phosphorus-based nanomaterials in biomedicine: theranostic applications.

Science.gov (United States)

Wang, Zhen; Liu, Zhiming; Su, Chengkang; Yang, Biwen; Fei, Xixi; Li, Yi; Hou, Yuqing; Zhao, Henan; Guo, Yanxian; Zhuang, Zhengfei; Zhong, Huiqing; Guo, Zhouyi

2017-09-20

Ascribe to the unique two-dimensional planar nanostructure with exceptional physical and chemical properties, black phosphorous (BP) as the emerging inorganic two-dimensional nanomaterial with high biocompatibility and degradability has been becoming one of the most promising materials of great potentials in biomedicine. The exfoliated BP sheets possess ultra-high surface area available for valid bio-conjugation and molecular loading for chemotherapy. Utilizing the intrinsic near-infrared optical absorbance, BP-based photothermal therapy in vivo, photodynamic therapy and biomedical imaging has been realized, achieving unprecedented anti-tumor therapeutic efficacy in animal experiments. Additionally, the BP nanosheets can strongly react with oxygen and water, and finally degrade to non-toxic phosphate and phosphonate in the aqueous solution. This manuscript aimed to summarize the preliminary progresses on theranostic application of BP and its derivatives black phosphorus quantum dots (BPQDs), and discussed the prospects and the state-of-art unsolved critical issues of using BP-based material for theranostic applications. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Black hole levitron

NARCIS (Netherlands)

Arsiwalla, X.D.; Verlinde, E.P.

2010-01-01

We study the problem of spatially stabilizing four dimensional extremal black holes in background electric/magnetic fields. Whilst looking for stationary stable solutions describing black holes placed in external fields we find that taking a continuum limit of Denef et al.’s multicenter

Black Hole Grabs Starry Snack

Science.gov (United States)

2006-01-01

[figure removed for brevity, see original site] Poster Version This artist's concept shows a supermassive black hole at the center of a remote galaxy digesting the remnants of a star. NASA's Galaxy Evolution Explorer had a 'ringside' seat for this feeding frenzy, using its ultraviolet eyes to study the process from beginning to end. The artist's concept chronicles the star being ripped apart and swallowed by the cosmic beast over time. First, the intact sun-like star (left) ventures too close to the black hole, and its own self-gravity is overwhelmed by the black hole's gravity. The star then stretches apart (middle yellow blob) and eventually breaks into stellar crumbs, some of which swirl into the black hole (cloudy ring at right). This doomed material heats up and radiates light, including ultraviolet light, before disappearing forever into the black hole. The Galaxy Evolution Explorer was able to watch this process unfold by observing changes in ultraviolet light. The area around the black hole appears warped because the gravity of the black hole acts like a lens, twisting and distorting light.

A nonsingular rotating black hole

International Nuclear Information System (INIS)

Ghosh, Sushant G.

2015-01-01

The spacetime singularities in classical general relativity are inevitable, as predicated by the celebrated singularity theorems. However, it is a general belief that singularities do not exist in Nature and that they are the limitations of the general relativity. In the absence of a welldefined quantum gravity, models of regular black holes have been studied. We employ a probability distribution inspired mass function m(r) to replace the Kerr black hole mass M to represent a nonsingular rotating black hole that is identified asymptotically (r >> k, k > 0 constant) exactly as the Kerr-Newman black hole, and as the Kerr black hole when k = 0. The radiating counterpart renders a nonsingular generalization of Carmeli's spacetime as well as Vaidya's spacetime, in the appropriate limits. The exponential correction factor changing the geometry of the classical black hole to remove the curvature singularity can also be motivated by quantum arguments. The regular rotating spacetime can also be understood as a black hole of general relativity coupled to nonlinear electrodynamics. (orig.)

Thermodynamic theory of black holes

Energy Technology Data Exchange (ETDEWEB)

Davies, P C.W. [King' s Coll., London (UK). Dept. of Mathematics

1977-04-21

The thermodynamic theory underlying black hole processes is developed in detail and applied to model systems. It is found that Kerr-Newman black holes undergo a phase transition at a = 0.68M or Q = 0.86M, where the heat capacity has an infinite discontinuity. Above the transition values the specific heat is positive, permitting isothermal equilibrium with a surrounding heat bath. Simple processes and stability criteria for various black hole situations are investigated. The limits for entropically favoured black hole formation are found. The Nernst conditions for the third law of thermodynamics are not satisfied fully for black holes. There is no obvious thermodynamic reason why a black hole may not be cooled down below absolute zero and converted into a naked singularity. Quantum energy-momentum tensor calculations for uncharged black holes are extended to the Reissner-Nordstrom case, and found to be fully consistent with the thermodynamic picture for Q < M. For Q < M the model predicts that 'naked' collapse also produces radiation, with such intensity that the collapsing matter is entirely evaporated away before a naked singularity can form.

A temporal comparison of forest cover using digital earth science data and visualization techniques

Science.gov (United States)

Jones, John W.

1993-01-01

Increased demands on forest resources and the recognition of old-growth forests as critical habitats and purifiers of the atmosphere have stimulated attention to forest harvest practices in the United States and worldwide. Visualization technology provides a means by which a history of forestry activities may be documented and presented to the public and decisionmakers. In this project, landsat multispectral scanner and thematic mapper images, acquired July 7, 1981, and July 8, 1991, respectively, were georeferenced, resampled, enhanced, and draped over U.S. Geological Survey 30-meter digital elevation models. These data then were used to create perspective views of portions of Mt. Hood Forest, Oregon. The "fly-by" animation (produced by rapidly displaying a sequence of these perspective views) conveys the forest cover change resulting from forest harvest activities over the 10-year period. This project shows the value of combining satellite data with base cartographic data and earth science information for use in public education and decision-making processes.

A Global Spectral Study of Stellar-Mass Black Holes with Unprecedented Sensitivity

Science.gov (United States)

Garci, Javier

project is a global spectroscopic studies of six bright black holes using our reflection models and new calibration tools. These synoptic studies will provide a panoramic view of black hole behavior and advance the measurement of black hole spin. The relevance of our proposed study to this NASA Research Announcement is clear because our work represents a vital use of NASA's High Energy Astrophysics Science Archive Research Center (HEASARC); conversely, it is the HEASARC that makes our work possible. In addition, our work naturally responds to the following words in the NRA: ``...the development of tools for mining the vast reservoir of information locked within [the HEASARC]...is also eligible for funding under the Astrophysics Data Analysis Program.'' Specifically we will provide new data analysis tools to the community for the study of data collected by a wide range of past, current and future X-ray missions (e.g., RXTE, Chandra, XMM-Newton, NuSTAR, Swift, NICER). Finally, we are responsive to Objective 1.6 in NASA's Strategic Plan for 2014 that calls for ``exploring the extreme conditions of the universe'' and the continuing aspiration to ``probe the origin and destiny of the universe, including the first moments of the Big Bang and the nature of black holes...''. The proposed program will be carried out over the course of three years.

Atypical features of hyperthyroidism in Blacks

International Nuclear Information System (INIS)

Kalk, W.J.

1980-01-01

Hyperthyroidism is reportedly uncommon in the indigenous populations of Africa. The presenting symptoms volunteered, the symptoms elicited by direct questioning, and the results of physical examination were therefore prospectively compared in 60 Black and 56 White patients with thyrotoxicosis attending a single thyroid clinic. Fewer Blacks than Whites volunteered information about weight loss, while more Blacks complained only of the presence of a goitre. A 'chance' diagnosis of hyperthyroidism was made more frequently in Blacks. Symptomatology elicited by direct questioning and findings on physical examination were generally similar in each group, except that Blacks presented more frequently with complicated disease (cardiac failure and overt myopathy) and infiltrative ophthalmopathy. The frequency with which hyperthyroidism presents 'atypically' in Black compared with White patients may reflect educational, socio-economic and cultural differences in the Black and White populations, and may partly explain the infrequency with which this disease is diagnosed in Blacks

Black layers on historical architecture.

Science.gov (United States)

Toniolo, Lucia; Zerbi, Carlotta M; Bugini, Roberto

2009-03-01

The external surface of any building in urban polluted environment is unavoidably destined to be covered with layers that assume a grey to black colour and are generally called 'black crusts'. These, according to standard protocols and glossary, are deteriorated surface layers of stone material; they can have variable thickness, are hard and fragile and can detach spontaneously from the substrate, which, in general, is quite decayed. Plain visual examination may lead to consider 'black crusts' all similar, whilst only a careful diagnostic investigation can distinguish 'black crusts' and the consequences of their formation on stone substrates. In this paper, various black layers on marble are studied and compared and the morphological and compositional characteristics discussed according to the related mechanisms of formation. Differences between old (hundred years) and recent crusts (30 years) are investigated and pointed out. Samples of black crusts collected from the Milan Cathedral façade (Candoglia Marble) have been studied and compared with the careful and synergic employ of traditional techniques: optical (transmission and reflected VIS light) and electron microscopy, X-ray spectrometry and micro-Fourier transform infrared spectroscopy. Visual examination of loose fragments does not allow to point out outstanding differences amongst the various samples; black layers have similar main mineral components, gypsum and airborne particles, with different spatial distribution. The microscopic studies allowed to point out the porosity differences, the gypsum crystallisation habit, different amount of embedded particles, level and progress of marble decay. The observations lead to define three main types of black crusts: black crust deriving from marble sulphation, compact deposit and encrustation due to exogenic materials deposition. Black crusts show evidence of sulphation in progress, without a clear continuity solution between crust and marble; the lack of

Nonsingular black hole

Energy Technology Data Exchange (ETDEWEB)

Chamseddine, Ali H. [American University of Beirut, Physics Department, Beirut (Lebanon); I.H.E.S., Bures-sur-Yvette (France); Mukhanov, Viatcheslav [Niels Bohr Institute, Niels Bohr International Academy, Copenhagen (Denmark); Ludwig-Maximilians University, Theoretical Physics, Munich (Germany); MPI for Physics, Munich (Germany)

2017-03-15

We consider the Schwarzschild black hole and show how, in a theory with limiting curvature, the physical singularity ''inside it'' is removed. The resulting spacetime is geodesically complete. The internal structure of this nonsingular black hole is analogous to Russian nesting dolls. Namely, after falling into the black hole of radius r{sub g}, an observer, instead of being destroyed at the singularity, gets for a short time into the region with limiting curvature. After that he re-emerges in the near horizon region of a spacetime described by the Schwarzschild metric of a gravitational radius proportional to r{sub g}{sup 1/3}. In the next cycle, after passing the limiting curvature, the observer finds himself within a black hole of even smaller radius proportional to r{sub g}{sup 1/9}, and so on. Finally after a few cycles he will end up in the spacetime where he remains forever at limiting curvature. (orig.)

Black Teenage Pregnancy

Directory of Open Access Journals (Sweden)

Loretta I. Winters

2012-01-01

Full Text Available This article examines the relative importance of race and socioeconomic status (SES in determining whether Black and White teenagers report having ever been pregnant. Data gathered from 1999 to 2006 by the National Center for Health Statistics of the Center for Disease Control and Prevention included 1,580 Black and White females aged 15 to 19 years. Results supported the effects of race and SES, with SES having the stronger effect. However, the effects of race and SES differ when controlling for the state of the economy. No difference between Blacks and Whites was found during better economic times. During 2003-2004, the period of greatest economic stress, race was determined to be the only predictor of teenage pregnancy. In particular, during 2005-2006, the reduction in pregnancy rates for Black minors (15-17 fell below those for White minors within their respective SES categories. Policy implications are discussed in light of these findings.

"What Exactly Is a Black?": Interrogating the Reality of Race in Jean Genet's The Blacks

Directory of Open Access Journals (Sweden)

Debby Thompson

2002-06-01

Full Text Available On the dedication page of The Blacks , Genet writes "One evening an actor asked me to write a play for an all-black cast. But what exactly is a black? First of all, what's his color?" Prefiguring major issues and paradoxes of African American cultural studies today, The Blacks insists on the very real ways in which the black/white racial binary, like the very concept of race itself, is lived and socially enforced, and at the same time argues that the binary is ultimately a fiction, made real through performative reification. Genet's "clown show," ambiguously reversing the blackface minstrelsy tradition, dramatizes how racial identity can become internalized and naturalized through cultural myths of interracial rape and colonialist narratives of a "heart of darkness," an imaginary site from which "black essence" arises. These racist performance traditions and narratives are so powerful and resilient that attempts to protest them become subtle and unwitting ways of re-creating them. The Blacks' parody of the minstrel tradition to interrogate all racial identity is so permanently suspended in a dialectic of both reinforcing the black/white binary and invalidating it, that the play's strategies present vital paradigms for the study of other and diverse interrogations of racial ontologies.

Identité et marchandisation : Le cas des black memorabilia et black collectibles Identity and Commodification: The Case of Black Memorabilia and Black Collectibles

Directory of Open Access Journals (Sweden)

Eliane Elmaleh

2009-07-01

Full Text Available The aim of this article is to raise the issue of the commodification of African American culture, mainly through a certain form of art that has re-emerged with Black memorabilia which paradoxically fit into a black-driven market. However, these items penetrated American culture from 1920 to the 1950s to convey images of black people as lazy, stupid, childlike and happy. This condition of permanent happiness, typified by a broad smile and white teeth, was a fundamental component of this racist and stereotyped imagery. Thus, this article focuses on the thin border between racism and the denunciation of racism, commodification and denunciation of commodification, art and its by-products being always co-opted in the specific logic of private productivity.

Black Girl Cartography: Black Girlhood and Place-Making in Education Research

Science.gov (United States)

Butler, Tamara T.

2018-01-01

Drawing on research in education, Black Girlhood studies, and conversations connected to girlhood and cartography, this chapter calls for transdisciplinary analyses of Black girls' sociocultural and geopolitical locations in education research. In reviewing education research documenting the practices and interrogating the experiences of Black…

Measuring Black Men’s Police-Based Discrimination Experiences: Development and Validation of the Police and Law Enforcement (PLE) Scale

Science.gov (United States)

English, Devin; Bowleg, Lisa; del Río-González, Ana Maria; Tschann, Jeanne M.; Agans, Robert; Malebranche, David J

2017-01-01

Objectives Although social science research has examined police and law enforcement-perpetrated discrimination against Black men using policing statistics and implicit bias studies, there is little quantitative evidence detailing this phenomenon from the perspective of Black men. Consequently, there is a dearth of research detailing how Black men’s perspectives on police and law enforcement-related stress predict negative physiological and psychological health outcomes. This study addresses these gaps with the qualitative development and quantitative test of the Police and Law Enforcement (PLE) scale. Methods In Study 1, we employed thematic analysis on transcripts of individual qualitative interviews with 90 Black men to assess key themes and concepts and develop quantitative items. In Study 2, we used 2 focus groups comprised of 5 Black men each (n=10), intensive cognitive interviewing with a separate sample of Black men (n=15), and piloting with another sample of Black men (n=13) to assess the ecological validity of the quantitative items. For study 3, we analyzed data from a sample of 633 Black men between the ages of 18 and 65 to test the factor structure of the PLE, as we all as its concurrent validity and convergent/discriminant validity. Results Qualitative analyses and confirmatory factor analyses suggested that a 5-item, 1-factor measure appropriately represented respondents’ experiences of police/law enforcement discrimination. As hypothesized, the PLE was positively associated with measures of racial discrimination and depressive symptoms. Conclusions Preliminary evidence suggests that the PLE is a reliable and valid measure of Black men’s experiences of discrimination with police/law enforcement. PMID:28080104

Axion-dilation black holes

International Nuclear Information System (INIS)

Kallosh, R.

1993-01-01

In this talk some essential features of stringy black holes are described. The author considers charged U(1) and U(1) x U(1) four-dimensional axion-dilaton black holes. The Hawking temperature and the entropy of all solutions are shown to be simple functions of the squares of supercharges, defining the positivity bounds. Spherically symmetric and multi black hole solutions are presented. The extreme solutions with zero entropy (holons) represent a ground state of the theory and are characterized by elementary dilaton, axion, electric, and magnetic charges. The attractive gravitational and axion-dilaton force is balanced by the repulsive electromagnetic force. The author discusses the possibility of splitting of nearly extreme black holes. 11 refs

Black History, Inc! Investigating the Production of Black History through Walmart's Corporate Web Site

Science.gov (United States)

King, LaGarrett J.; Brown, Anthony L.

2012-01-01

Social and public sites are becoming a popular medium for intellectual consumption of Black history. Given the educational climate in which many students' exposure to Black history may come from outside of schools, the authors examine how Walmart's Black History Month Web site produced simplistic and safe narratives about African American history.

What Can We Learn About Black-Hole Formation from Black-Hole X-ray Binaries?

NARCIS (Netherlands)

Nelemans, G.A.

2007-01-01

I discuss the effect of the formation of a black hole on a (close) binary and show some of the current constraints that the observed properties of black hole X-ray binaries put on the formation of black holes. In particular, I discuss the evidence for and against asymmetric kicks imparted on the

Why Are Black Employers More Likely Than White Employers To Hire Blacks? Discussion Paper.

Science.gov (United States)

Stoll, Michael A.; Raphael, Steven; Holzer, Harry J.

This study investigated why black employers tend to hire blacks at higher rates than do white employers and examined individual steps in the hiring process, the role of the hiring agent's race, and the degree to which variation in black application rates related to differences in observable characteristics, such as an establishment's physical…

Black holes and the multiverse

International Nuclear Information System (INIS)

Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun

2016-01-01

Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse

Black holes and the multiverse

Energy Technology Data Exchange (ETDEWEB)

Garriga, Jaume [Departament de Fisica Fonamental i Institut de Ciencies del Cosmos, Universitat de Barcelona, Marti i Franques, 1, Barcelona, 08028 Spain (Spain); Vilenkin, Alexander; Zhang, Jun, E-mail: jaume.garriga@ub.edu, E-mail: vilenkin@cosmos.phy.tufts.edu, E-mail: jun.zhang@tufts.edu [Institute of Cosmology, Tufts University, 574 Boston Ave, Medford, MA, 02155 (United States)

2016-02-01

Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse.

Measuring Black men's police-based discrimination experiences: Development and validation of the Police and Law Enforcement (PLE) Scale.

Science.gov (United States)

English, Devin; Bowleg, Lisa; Del Río-González, Ana Maria; Tschann, Jeanne M; Agans, Robert P; Malebranche, David J

2017-04-01

Although social science research has examined police and law enforcement-perpetrated discrimination against Black men using policing statistics and implicit bias studies, there is little quantitative evidence detailing this phenomenon from the perspective of Black men. Consequently, there is a dearth of research detailing how Black men's perspectives on police and law enforcement-related stress predict negative physiological and psychological health outcomes. This study addresses these gaps with the qualitative development and quantitative test of the Police and Law Enforcement (PLE) Scale. In Study 1, we used thematic analysis on transcripts of individual qualitative interviews with 90 Black men to assess key themes and concepts and develop quantitative items. In Study 2, we used 2 focus groups comprised of 5 Black men each (n = 10), intensive cognitive interviewing with a separate sample of Black men (n = 15), and piloting with another sample of Black men (n = 13) to assess the ecological validity of the quantitative items. For Study 3, we analyzed data from a sample of 633 Black men between the ages of 18 and 65 to test the factor structure of the PLE, as we all as its concurrent validity and convergent/discriminant validity. Qualitative analyses and confirmatory factor analyses suggested that a 5-item, 1-factor measure appropriately represented respondents' experiences of police/law enforcement discrimination. As hypothesized, the PLE was positively associated with measures of racial discrimination and depressive symptoms. Preliminary evidence suggests that the PLE is a reliable and valid measure of Black men's experiences of discrimination with police/law enforcement. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Afican Health Sciences Vol 10 No 1.pmd

African Journals Online (AJOL)

Administrator

African Health Sciences Vol 10 No 1 March 2010. 89. Rethinking ... There is a worsening scarcity of Human Resource for ... This is not in any way lowering standards of oncologic diagnosis but filling the otherwise ... for health ratios stand at 0.8 health workers per 1000 ... cancer occurs 10-15years earlier in black women.

Super-horizon primordial black holes

International Nuclear Information System (INIS)

Harada, Tomohiro; Carr, B.J.

2005-01-01

We discuss a new class of solutions to the Einstein equations which describe a primordial black hole (PBH) in a flat Friedmann background. Such solutions arise if a Schwarzschild black hole is patched onto a Friedmann background via a transition region. They are possible providing the black hole event horizon is larger than the cosmological apparent horizon. Such solutions have a number of strange features. In particular, one has to define the black hole and cosmological horizons carefully and one then finds that the mass contained within the black hole event horizon decreases when the black hole is larger than the Friedmann cosmological apparent horizon, although its area always increases. These solutions involve two distinct future null infinities and are interpreted as the conversion of a white hole into a black hole. Although such solutions may not form from gravitational collapse in the same way as standard PBHs, there is nothing unphysical about them, since all energy and causality conditions are satisfied. Their conformal diagram is a natural amalgamation of the Kruskal diagram for the extended Schwarzschild solution and the conformal diagram for a black hole in a flat Friedmann background. In this paper, such solutions are obtained numerically for a spherically symmetric universe containing a massless scalar field, but it is likely that they exist for more general matter fields and less symmetric systems

THE BITTER TRUTH: A COMPARATIVE ANALYSIS OF BLACK MALE AND BLACK FEMALE ENTREPRENEURS

OpenAIRE

SHERRHONDA R. GIBBS

2014-01-01

The paper examines variables stated to be central to entrepreneurial success and reports differences between black male and black female entrepreneurs. Variables studied include task-specific efficacy, firm performance and opportunity recognition. Using a sample of 85 males and 58 females, results indicated that although black male and female entrepreneurs are somewhat similar in terms of business environment and demographics (e.g., education levels, years of business industry experience, lik...

When Supermassive Black Holes Wander

Science.gov (United States)

Kohler, Susanna

2018-05-01

Are supermassive black holes found only at the centers of galaxies? Definitely not, according to a new study in fact, galaxies like the Milky Way may harbor several such monsters wandering through their midst.Collecting Black Holes Through MergersIts generally believed that galaxies are built up hierarchically, growing in size through repeated mergers over time. Each galaxy in a major merger likely hosts a supermassive black hole a black hole of millions to billions of times the mass of the Sun at its center. When a pair of galaxies merges, their supermassive black holes will often sink to the center of the merger via a process known as dynamical friction. There the supermassive black holes themselves will eventually merge in a burst of gravitational waves.Spatial distribution and velocities of wandering supermassive black holes in three of the authors simulated galaxies, shown in edge-on (left) and face-on (right) views of the galaxy disks. Click for a closer look. [Tremmel et al. 2018]But if a galaxy the size of the Milky Way was built through a history of many major galactic mergers, are we sure that all its accumulated supermassive black holes eventually merged at the galactic center? A new study suggests that some of these giants might have escaped such a fate and they now wander unseen on wide orbits through their galaxies.Black Holes in an Evolving UniverseLed by Michael Tremmel (Yale Center for Astronomy Astrophysics), a team of scientists has used data from a large-scale cosmological simulation, Romulus25, to explore the possibility of wandering supermassive black holes. The Romulus simulations are uniquely suited to track the formation and subsequent orbital motion of supermassive black holes as galactic halos are built up through mergers over the history of the universe.From these simulations, Tremmel and collaborators find an end total of 316 supermassive black holes residing within the bounds of 26 Milky-Way-mass halos. Of these, roughly a third are

Black powder in gas pipelines

Energy Technology Data Exchange (ETDEWEB)

Sherik, Abdelmounam [Saudi Aramco, Dhahran (Saudi Arabia)

2009-07-01

Despite its common occurrence in the gas industry, black powder is a problem that is not well understood across the industry, in terms of its chemical and physical properties, source, formation, prevention or management of its impacts. In order to prevent or effectively manage the impacts of black powder, it is essential to have knowledge of its chemical and physical properties, formation mechanisms and sources. The present paper is divided into three parts. The first part of this paper is a synopsis of published literature. The second part reviews the recent laboratory and field work conducted at Saudi Aramco Research and Development Center to determine the compositions, properties, sources and formation mechanisms of black powder in gas transmission systems. Microhardness, nano-indentation, X-ray Diffraction (XRD), X-ray Fluorescence (XRF) and Scanning Electron Microscopy (SEM) techniques were used to analyze a large number of black powder samples collected from the field. Our findings showed that black powder is generated inside pipelines due to internal corrosion and that the composition of black powder is dependent on the composition of transported gas. The final part presents a summary and brief discussion of various black powder management methods. (author)

Anyon black holes

Science.gov (United States)

Aghaei Abchouyeh, Maryam; Mirza, Behrouz; Karimi Takrami, Moein; Younesizadeh, Younes

2018-05-01

We propose a correspondence between an Anyon Van der Waals fluid and a (2 + 1) dimensional AdS black hole. Anyons are particles with intermediate statistics that interpolates between a Fermi-Dirac statistics and a Bose-Einstein one. A parameter α (0 quasi Fermi-Dirac statistics for α >αc, but a quasi Bose-Einstein statistics for α quasi Bose-Einstein statistics. For α >αc and a range of values of the cosmological constant, there is, however, no event horizon so there is no black hole solution. Thus, for these values of cosmological constants, the AdS Anyon Van der Waals black holes have only quasi Bose-Einstein statistics.

Black-hole driven winds

International Nuclear Information System (INIS)

Punsly, B.M.

1988-01-01

This dissertation is a study of the physical mechanism that allows a large scale magnetic field to torque a rapidly rotating, supermassive black hole. This is an interesting problem as it has been conjectured that rapidly rotating black holes are the central engines that power the observed extragalactic double radio sources. Axisymmetric solutions of the curved space-time version of Maxwell's equations in the vacuum do not torque black holes. Plasma must be introduced for the hole to mechanically couple to the field. The dynamical aspect of rotating black holes that couples the magnetic field to the hole is the following. A rotating black hole forces the external geometry of space-time to rotate (the dragging of inertial frames). Inside of the stationary limit surface, the ergosphere, all physical particle trajectories must appear to rotate in the same direction as the black hole as viewed by the stationary observers at asymptotic infinity. In the text, it is demonstrated how plasma that is created on field lines that thread both the ergosphere and the equatorial plane will be pulled by gravity toward the equator. By the aforementioned properties of the ergosphere, the disk must rotate. Consequently, the disk acts like a unipolar generator. It drives a global current system that supports the toroidal magnetic field in an outgoing, magnetically dominated wind. This wind carries energy (mainly in the form of Poynting flux) and angular momentum towards infinity. The spin down of the black hole is the ultimate source of this energy and angular momentum flux

ULTRAMASSIVE BLACK HOLE COALESCENCE

International Nuclear Information System (INIS)

Khan, Fazeel Mahmood; Holley-Bockelmann, Kelly; Berczik, Peter

2015-01-01

Although supermassive black holes (SMBHs) correlate well with their host galaxies, there is an emerging view that outliers exist. Henize 2-10, NGC 4889, and NGC 1277 are examples of SMBHs at least an order of magnitude more massive than their host galaxy suggests. The dynamical effects of such ultramassive central black holes is unclear. Here, we perform direct N-body simulations of mergers of galactic nuclei where one black hole is ultramassive to study the evolution of the remnant and the black hole dynamics in this extreme regime. We find that the merger remnant is axisymmetric near the center, while near the large SMBH influence radius, the galaxy is triaxial. The SMBH separation shrinks rapidly due to dynamical friction, and quickly forms a binary black hole; if we scale our model to the most massive estimate for the NGC 1277 black hole, for example, the timescale for the SMBH separation to shrink from nearly a kiloparsec to less than a parsec is roughly 10 Myr. By the time the SMBHs form a hard binary, gravitational wave emission dominates, and the black holes coalesce in a mere few Myr. Curiously, these extremely massive binaries appear to nearly bypass the three-body scattering evolutionary phase. Our study suggests that in this extreme case, SMBH coalescence is governed by dynamical friction followed nearly directly by gravitational wave emission, resulting in a rapid and efficient SMBH coalescence timescale. We discuss the implications for gravitational wave event rates and hypervelocity star production

Protecting Black Girls

Science.gov (United States)

Morris, Monique W.

2016-01-01

Statistics show that black girls in U.S. K-12 public schools are overrepresented among students who face disciplinary approaches (such as suspensions) that exclude or even criminalize them. Morris explains how black girls face conditions that make them vulnerable to a phenomenon she calls "school to confinement pathways"--conditions like…

Black holes a very short introduction

CERN Document Server

Blundell, Katherine

2015-01-01

Black holes are a constant source of fascination to many due to their mysterious nature. Black Holes: A Very Short Introduction addresses a variety of questions, including what a black hole actually is, how they are characterized and discovered, and what would happen if you came too close to one. It explains how black holes form and grow—by stealing material that belongs to stars—as well as how many there may be in the Universe. It also explores the large black holes found in the centres of galaxies, and how black holes power quasars and lie behind other spectacular phenomena in the cosmos.

Dye-sensitized solar cells fabricated with black raspberry, black carrot and rosella juice