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  1. AN UPDATED REVIEW ON MOLECULAR GENETICS, PHYTOCHEMISTRY, PHARMACOLOGY AND PHYSIOLOGY OF BLACK NIGHTSHADE (SOLANUM NIGRUM

    Directory of Open Access Journals (Sweden)

    Ashwani Kumar*, S. Sagwal, Niketa and S. Rani

    2012-09-01

    Full Text Available This article reviews, connected the gap between the folkloric use of Solanum nigrum and the results of evidence based experiments. Although Solanum nigrum is a rich source of one of plants most dreaded toxins solanine, it has appreciably monstrated its potential as a reservoir of antioxidants having hepatoprotective, anti-tumor, cytostatic, anti-convulsant, anti-ulcerogenic and anti-inflammatory.effects. The review encompasses in-vitro, in vivo and clinical studies done on Solanum nigrum, while examining.whether or not correct scientific measures have been taken in generating experimental evidences for its traditional uses. This review would afford research scientist to know how much is known and what is left undone in the investigation of Solanum nigrum. The compounds considered in this revieware flavonoids and other phenolics, alkaloids (especially indole terpenoid and purine alkaloids, essential oils and other terpenoids, cannabinoids, lucosinolates and isothiocyanates, and compounds having human hormone activity. The review concludes with a discussion of the possible evolutionary mechanisms that have led to the evolution of UV-B regulation of secondary metabolite accumulation. Many Ayurveda philosophers and healers praised about the properties of this plant and utilized in various disorders. Here, a review made on the screening of Solanum nigrum for various activities. It is found that the drug is very potential and can be used for various applications as mentioned in Ayurveda. Black nightshade grows as a weed, found in the dry parts of India and other parts of the world. It has a medicinal usage and has been used as a traditional folk medicine for treating various ailments such as pain, fever and liver disorders. Generally, black nightshade is very rich in nutritive values, which are capable of supplying minerals, vitamins, hormones and proteins. This herb elaborates a wide variety of medicinal properties such as anticancer, antioxidant

  2. Plant metabolites of polychlorinated biphenyls in hairy root culture of black nightshade Solanum nigrum SNC-9O.

    Science.gov (United States)

    Rezek, Jan; Macek, Tomas; Mackova, Martina; Triska, Jan

    2007-10-01

    The present study is intended to determine metabolites of 12 dichlorinated, seven trichlorinated, five tetrachlorinated and one pentachlorinated PCB congener transformed by black nightshade (Solanum nigrum) hairy root culture SNC-9O. Free hydroxylated PCB metabolites were identified based on the mass spectra characteristics after gas chromatography separation. The number of metabolites decreases with an increasing number of chlorine atoms per molecule of PCB. Dichlorinated PCBs lead always to at least two metabolites. In the case of PCB 9 some metabolites could be identified by comparing their RF values due to available standards. The 2',5'-dichloro-2-biphenylol, 2',5'-dichloro-3-biphenylol and 2',5'-dichloro-4-biphenylol, present as the main metabolite, were found in biomass of SNC-9O hairy root culture. Two monochlorinated biphenylols were found in biomass of SNC-9O degrading PCB 9 congener. It was the only case when metabolites with decreased number of chlorine atoms compared to parent PCB were found. Trichlorinated PCBs mostly lead to a lower number of metabolites but tetrachlorinated and pentachlorinated PCBs mostly did not give any metabolites. In the media, only traces of metabolites were found in sporadic cases, so exudation of unbound biphenylols from the cells is not expected.

  3. Volatile constituents of commercial imported and domestic black-ripe table olives (Olea europaea)

    Science.gov (United States)

    Volatile constituents of commercial black-ripe table olives (Olea europaea) from the United States, Spain, Egypt and Morocco were analyzed by gas chromatography and gas chromatography-mass spectrometry (GC-MS). Dynamic headspace sampling was used to isolate a variety of aldehydes, alcohols, esters, ...

  4. Evaluation of thermal processing variables for reducing acrylamide in canned black ripe olives

    Science.gov (United States)

    Acrylamide formed in plant foods at elevated cooking temperatures has been identified as a probable carcinogen. A wide variation and high acrylamide concentration in commercial canned black ripe olives has been reported. The objective of this study was to determine if different safe sterilization co...

  5. Influence of California-style black ripe olive processing on the formation of acrylamide.

    Science.gov (United States)

    Charoenprasert, Suthawan; Mitchell, Alyson

    2014-08-27

    Methods used in processing California-style black ripe olives generate acrylamide. California-style black ripe olives contain higher levels of acrylamide (409.67 ± 42.60-511.91 ± 34.08 μg kg(-1)) as compared to California-style green ripe olives (44.02 ± 3.55-105.79 ± 22.01 μg kg(-1)), Greek olives (acrylamide formation. Preprocessing brine storage influenced the formation of acrylamide in a time-dependent manner. Acrylamide increased during the first 30 days of storage. Longer brine storage times (>30 days) result in lower acrylamide levels in the finished product. The presence of calcium ions in the preprocessing brining solution results in higher levels of acrylamide in finished products. Air oxidation during lye processing and the neutralization of olives prior to sterilization significantly increase the formation of acrylamide in the finished products. Conversely, lye-processing decreases the levels of acrylamide in the final product. These results indicate that specific steps in the California-style black ripe olive processing may be manipulated to mitigate the formation of acrylamide in finished products.

  6. Nightshade Prototype Experiments (Silverleaf)

    Energy Technology Data Exchange (ETDEWEB)

    Danielson, Jeremy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bauer, Amy L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-23

    The Red Sage campaign is a series of subcritical dynamic plutonium experiments designed to measure ejecta. Nightshade, the first experiments in Red Sage scheduled for fiscal year 2019, will measure the amount of ejecta emission into vacuum from a double-­shocked plutonium surface. To address the major technical risks in Nightshade, a Level 2 milestone was developed for fiscal year 2016. Silverleaf, a series of four experiments, was executed at the Los Alamos National Laboratory in July and August 2016 to demonstrate a prototype of the Nightshade package and to satisfy this Level 2 milestone. This report is documentation that Red Sage Level 2 milestone requirements were successfully met.

  7. Influence of processing conditions on acrylamide content in black ripe olives.

    Science.gov (United States)

    Casado, Francisco J; Montaño, Alfredo

    2008-03-26

    The presence of acrylamide was investigated in different presentations of commercial black ripe olives, a well-known sterilized alkali-treated product. The analysis was performed by gas chromatography-mass spectrometry (GC-MS) after bromination of acrylamide, using (13C3)acrylamide as internal standard. In-house validation data for commercial ripe olives showed good precision and accuracy of the method, with repeatability below 3% and recoveries between 94 and 105%. Acrylamide was detected in all samples, but its concentration varied significantly from 176 to 1578 microg/kg of pulp. The effects of different processing conditions (two preservation methods and three darkening methods), cultivar (Hojiblanca or Manzanilla), and presentation form (pitted or sliced olives) on acrylamide content were evaluated in experiments performed in an olive-processing plant. All canned samples were sterilized at 121 degrees C for 30 min. Statistical analysis of the data indicated that the effects of darkening method and olive cultivar were the most pronounced. Acrylamide contents did not significantly differ after 6 months of storage. The small amounts of free amino acids and reducing sugars found in olives before sterilization did not significantly correlate with the acrylamide formed.

  8. Metabolites of 2,2'-dichlorobiphenyl and 2,6-dichlorobiphenyl in hairy root culture of black nightshade Solanum nigrum SNC-9O.

    Science.gov (United States)

    Rezek, Jan; Macek, Tomas; Doubsky, Jan; Mackova, Martina

    2012-10-01

    The hairy root culture of black nightshade (Solanum nigrum) SNC-9O was exposed to 2,2'-dichlorobiphenyl (PCB 4) and 2,6-dichlorobiphenyl (PCB 10) to follow the metabolites produced. The analytical standards of 4-hydroxy-2,2'-dichlorobiphenyl, 5'-hydroxy-2,2'-dichlorobiphenyl, 4-hydroxy-2,6-dichlorobiphenyl, 2-hydroxy-2',6'-dichlorobiphenyl, 3-hydroxy-2',6'-dichlorobiphenyl and 4-hydroxy-2',6'-dichlorobiphenyl have been synthesized. Hydroxy-metabolites of both PCB 4 and PCB 10 were present in the biomass. These appeared mainly as conjugates rather than as free hydroxy-PCBs, both maintained in plant cells. The concentrations of non-conjugated hydroxy-PCBs ranged between 0.9 and 35.2 μg kg(-1) of biomass fresh weight and the concentration of the conjugated ones ranged between 2.0 and 113.0 μg kg(-1) depending on the position of hydroxyl. The para- position of biphenyl (4 or 4') seems to be preferred for hydroxylation. Methoxy-PCBs and hydroxy-methoxy-PCBs have also been identified in plant cells. Hydroxyl in the meta-position (3, 3', 5 or 5') appears to be preferred for methylation in hydroxy-PCBs. Hydroxy-methoxy-PCBs have occurred in the conjugated form as well.

  9. Impacto da erva-moira na produção do tomateiro e ajuste de modelos matemáticos Impact of black nightshade on tomato plant production and mathematical model fitness

    Directory of Open Access Journals (Sweden)

    J.M Portugal

    2009-12-01

    Full Text Available Modelos matemáticos são úteis para estimar o impacto das infestantes nas culturas. Os objetivos deste trabalho foram: elucidar a interação de Solanum nigrum (ervamoira ou maria-pretinha com o tomateiro no sistema de sementeira direta e transplantado; e avaliar o impacto de diferentes densidades de infestação e períodos de tempo de competição na quantidade de frutos do tomateiro. Entre os anos 1991 e 2001, foram conduzidos cinco experimentos em campo na região tomaticultora de Portugal. Os experimentos seguiram o método aditivo, mantendo-se constante a densidade da cultura, enquanto o número de ervas-moiras variou entre 0 e 6 plantas m-2. Outro fator avaliado foi o período de convivência da infestante na cultura, incluindo os períodos do transplante/semeadura e o início da floração até a colheita. Os resultados de perda de produção foram ajustados aos modelos linear e hiperbólico. O comportamento das perdas de produção nas densidades mais baixas de erva-moira é do tipo linear. A erva-moira é uma espécie muito competitiva em relação ao tomateiro tanto quando a cultura é semeada quanto quando é transplantada. As perdas de produção foram maiores quando a cultura foi semeada, em comparação com a transplantada.Mathematical models are useful for estimating the impact of weeds on crops. The objectives of this study were to elucidate the interaction of Solanum nigrum (black nightshade with tomato plants in direct and transplanted sowing and to evaluate the impact of different infestation densities and competition time periods on tomato plant production. Between 1991 and 2001, five field experiments were conducted in the tomato growing region of Portugal using the additive method, keeping crop density constant, while changing the number of weeds from 0 and 6 plants m-2. The weed and crop coexistence period was also evaluated, from transplantation/sowing to the beginning of flowering or until harvest. The tomato yield

  10. Anticholinergic toxicity from nightshade berry poisoning responsive to physostigmine.

    Science.gov (United States)

    Ceha, L J; Presperin, C; Young, E; Allswede, M; Erickson, T

    1997-01-01

    The woody nightshade, Solanum dulcamara, belongs to the genus Solanum and its primary toxin is solanine. We report a large nightshade ingestion in a 4-yr-old girl who presented to the emergency department in acute anticholinergic crisis. The child was given 0.2 mg of intravenous physostigmine (0.02 mg/kg). Within 50 min, the patient received two additional equal doses with complete resolution of symptoms. After 36 h of observation, the child was discharged. Our patient presented with symptoms more suggestive of the deadly nightshade species, Atropa belladonna, which is native to Europe; however, a detailed laboratory analysis of the suspect berries revealed no atropine or hyoscyamine. Analysis did reveal sterols consistent with solanine. This is a unique case presentation of woody nightshade, S. dulcamara, poisoning presenting with anticholinergic crisis and responding to physostigmine.

  11. Ripeness sensor development

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    About 20--25% of the total production of fruits and vegetables in the USA must be discarded after harvest About 25--30% of this loss is the result of over-ripening and this loss represents about 8.39 [times] 10[sup 12] BTU of invested energy every year. This invested energy could be saved by non-destructive ripeness sensing. Sweetness is an important indicator of fruit quality and highly correlated with ripeness in most fruits. Research to develop a non-destructive fruit ripeness sensor has been conducted in the Agricultural Engineering Department at Purdue University. It is based on [sup 1]H-MR (proton Magnetic Resonance). A first generation prototype of the ripeness sensor based on [sup 1]H-MR was built and tested with. Results show that the sensor can discriminate small fruit (0.75 in diameter or smaller) differing in sugar content by 6%. This prototype can separate the fruit into at least two groups: one ripe and the other not ripe. The estimated cost for such a ripeness sensor is around $4,000. The signal sensitivity of the prototype can be improved to enable it to differentiate between fruits varying in sugar content by only 1 or 2% by using water peak suppression techniques to recover relatively weak sugar resonance signals in intact fruits, modifying circuits to eliminate noise, leakage and distortion of input/output signals, improving the magnetic console to get a higher magnetic field and better homogeneity, and designing a probe to achieve a higher signal-to-noise (S/N) ratio. As research continues a second generation ripeness sensor will be developed which will incorporate many of the improvements and which will be suitable for commercial use. Additional research will allow application of the technique to a wider range of fruit sizes (from blueberries to watermelons). This report describes estimated energy savings, feasibility studies, development of the initial prototype, and preliminary evaluation of the first generation prototype.

  12. Flowering and tuberization: a tale of two nightshades.

    Science.gov (United States)

    Abelenda, José A; Navarro, Cristina; Prat, Salomé

    2014-02-01

    The concept of florigen, postulated in the early 1930s, has taken form after the identification of the FLOWERING LOCUS T (FT) protein as the flowering-inducing signal. Besides their role in flowering, FT genes were subsequently reported to play additional functions in other biological processes. This is particularly relevant in the nightshades, where the FT genes appear to have undergone considerable expansion at the functional level and gained a new role in the control of storage organ formation in potato (Solanum tuberosum). Neofunctionalization of FT homologs in the nightshades identifies these proteins as a new class of primary signaling components that modulate development and organogenesis in these agronomic relevant species.

  13. Silverleaf: An Experimental Series in Support of Nightshade

    Energy Technology Data Exchange (ETDEWEB)

    Danielson, Jeremy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bauer, Amy L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-23

    In this series, a prototype package was designed and fielded to address a major technical risk of Nightshade: A comprehensive suite of drives and diagnostics must fit within a small space. In addition, this series satisfies a milestone for the project.

  14. Ripeness sensor development. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    About 20--25% of the total production of fruits and vegetables in the USA must be discarded after harvest About 25--30% of this loss is the result of over-ripening and this loss represents about 8.39 {times} 10{sup 12} BTU of invested energy every year. This invested energy could be saved by non-destructive ripeness sensing. Sweetness is an important indicator of fruit quality and highly correlated with ripeness in most fruits. Research to develop a non-destructive fruit ripeness sensor has been conducted in the Agricultural Engineering Department at Purdue University. It is based on {sup 1}H-MR (proton Magnetic Resonance). A first generation prototype of the ripeness sensor based on {sup 1}H-MR was built and tested with. Results show that the sensor can discriminate small fruit (0.75 in diameter or smaller) differing in sugar content by 6%. This prototype can separate the fruit into at least two groups: one ripe and the other not ripe. The estimated cost for such a ripeness sensor is around $4,000. The signal sensitivity of the prototype can be improved to enable it to differentiate between fruits varying in sugar content by only 1 or 2% by using water peak suppression techniques to recover relatively weak sugar resonance signals in intact fruits, modifying circuits to eliminate noise, leakage and distortion of input/output signals, improving the magnetic console to get a higher magnetic field and better homogeneity, and designing a probe to achieve a higher signal-to-noise (S/N) ratio. As research continues a second generation ripeness sensor will be developed which will incorporate many of the improvements and which will be suitable for commercial use. Additional research will allow application of the technique to a wider range of fruit sizes (from blueberries to watermelons). This report describes estimated energy savings, feasibility studies, development of the initial prototype, and preliminary evaluation of the first generation prototype.

  15. Toxicity of nightshade berries (Solanum dulcamara) in mice.

    Science.gov (United States)

    Hornfeldt, C S; Collins, J E

    1990-01-01

    Ripened nightshade berries (Solanum dulcamara) are among the most commonly reported plant ingestions in Minnesota. Because of the lack of adequate information regarding the toxic qualities of S. dulcamara berries, the ingestion of even small quantities by children is usually treated conservatively with syrup of ipecac. The toxicity of S. dulcamara berries was studied by gavaging mice with a preparation of lyophilized berries, ripened and unripened, collected at various times of the year. Mice receiving unripened fruit from early in the season had gastrointestinal tissue changes consistent with solanine toxicity. Animals dosed with unripened fruit from the latter part of the year showed behavioral signs suggestive of solanine toxicity, however gastrointestinal lesions were not observed. In no case did the ripened fruit produce behavioral or histologic toxicity. Aggressive treatment of children ingesting limited amounts of ripened S. dulcamara berries appears to be unnecessary.

  16. Distribution, ecology and reproductive biology of wild tomatoes and related nightshades from the Atacama Desert region of northern Chile

    OpenAIRE

    Chetelat, Roger T.; Pertuzé, Ricardo A.; Faúndez, Luis; Graham, Elaine B.; Jones, Carl M.

    2009-01-01

    Over the past 20 years, several expeditions were made to northern Chile to collect populations of wild tomatoes (Solanum chilense, S. peruvianum) and allied nightshades (S. lycopersicoides, S. sitiens), and obtain information about their geographic distribution, ecology and reproductive biology. Restricted mainly to drainages of the Andean and the coastal cordillera, populations are geographically fragmented. The two nightshade species are rare and threatened by human activities. Adaptation t...

  17. Ouyang Riping: A Hero Besides Entrepreneur

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

      About fifty years ago, a baby's cry broke the sky of quietness, in a small and beautiful town of Hunan province, which surrounded by green hills and clear water. Though his birth brought his family great happiness and hope just as any new life, nobody knew that the little boy would get great achievement when he grow up, even start his business oversea, and earn international honor. Let's share with you the entrepreneur Ouyang Riping's story, which may insights these people who want to succeed and complete oneself in favorite condition or adversity rather leave things to so-called fate.……

  18. Ouyang Riping: A Hero Besides Entrepreneur

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ About fifty years ago, a baby's cry broke the sky of quietness, in a small and beautiful town of Hunan province, which surrounded by green hills and clear water. Though his birth brought his family great happiness and hope just as any new life, nobody knew that the little boy would get great achievement when he grow up, even start his business oversea, and earn international honor. Let's share with you the entrepreneur Ouyang Riping's story, which may insights these people who want to succeed and complete oneself in favorite condition or adversity rather leave things to so-called fate.

  19. Progress of International Cooperation Between RIPED and Foreign Institute

    Institute of Scientific and Technical Information of China (English)

    Wang Shaoxian

    1996-01-01

    @@ As the petroleum exploration and development research center of CNPC, Research Institute of Petroleum Exploration & Development (RIPED) has conscientiously been engaged in international academic exchanges for years. Every year, hundreds of petroleum researchers and petroleum engineering experts come to RIPED taking part in various kinds or scales of academic exchange activities and joint-research work.

  20. Opposing Roles of Foliar and Glandular Trichome Volatile Components in Cultivated Nightshade Interaction with a Specialist Herbivore

    Science.gov (United States)

    Murungi, Lucy Kananu; Kirwa, Hillary; Salifu, Daisy; Torto, Baldwyn

    2016-01-01

    Plant chemistry is an important contributor to the interaction with herbivores. Here, we report on a previously unknown role for foliar and glandular trichome volatiles in their interaction with the specialist herbivore of solanaceous plants, the tomato red spider mite Tetranychus evansi. We used various bioassays and chemical analyses including coupled gas chromatography-mass spectrometry (GC/MS) and liquid chromatography coupled to quadrupole time of flight mass spectrometry (LC-QToF-MS) to investigate this interaction between cultivated African nightshades and T. evansi. We show that, whereas morphologically different cultivated African nightshade species released similar foliar volatile organic compounds (VOCs) that attracted T. evansi, VOCs released from exudates of ruptured glandular trichomes of one nightshade species influenced local defense on the leaf surface. VOCs from ruptured glandular trichomes comprising mainly saturated and unsaturated fatty acids deterred T. evansi oviposition. Of the fatty acids, the unsaturated fatty acids accounted for >40% of the oviposition deterrent activity. Our findings point to a defense strategy in a plant, based on opposing roles for volatiles released by foliar and glandular trichomes in response to attack by a specialist herbivore. PMID:27556560

  1. RIPED and IFP Built a Long-term Cooperative Partnership

    Institute of Scientific and Technical Information of China (English)

    Wang Mingyi

    2005-01-01

    @@ On March 15, the general geologist of PetroChina and the dean of Research Institute Petroleum Exploration and Development,CNPC (RIPED), Mr. Jia Chengzao, and the scientific and development principals in the aspects of exploration and development, refining & marketing, natural gas & pipelines and from RIPED met 8 specialists leading by Mr.Olivier Appert, the dean of Institut Francais du Pétrole (IFP). The two sides exchanged ideas broadly on the research topics that both parties were interested in commonly and signed a memorandum of understanding for building a long-term cooperative partnership between RIPED and IFP.

  2. Two-dimensional fruit ripeness estimation using thermal imaging

    Science.gov (United States)

    Sumriddetchkajorn, Sarun; Intaravanne, Yuttana

    2013-06-01

    Some green fruits do not change their color from green to yellow when being ripe. As a result, ripeness estimation via color and fluorescent analytical approaches cannot be applied. In this article, we propose and show for the first time how a thermal imaging camera can be used to two-dimensionally classify fruits into different ripeness levels. Our key idea relies on the fact that the mature fruits have higher heat capacity than the immature ones and therefore the change in surface temperature overtime is slower. Our experimental proof of concept using a thermal imaging camera shows a promising result in non-destructively identifying three different ripeness levels of mangoes Mangifera indica L.

  3. Hyperspectral Surface Analysis for Ripeness Estimation and Quick UV-C Surface Treatments for Preservation of Bananas

    Science.gov (United States)

    Zhao, W.; Yang, Zh.; Chen, Zh.; Liu, J.; Wang, W. Ch.; Zheng, W. Yu.

    2016-05-01

    This study aimed to determine the ripeness of bananas using hyperspectral surface analysis and how a rapid UV-C (ultraviolet-C light) surface treatment could reduce decay. The surface of the banana fruit and its stages of maturity were studied using a hyperspectral imaging technique in the visible and near infrared (370-1000 nm) regions. The vselected color ratios from these spectral images were used for classifying the whole banana into immature, ripe, half-ripe and overripe stages. By using a BP neural network, models based on the wavelengths were developed to predict quality attributes. The mean discrimination rate was 98.17%. The surface of the fresh bananas was treated with UV-C at dosages from 15-55 μW/cm2. The visual qualities with or without UV-C treatment were compared using the image, the chromatic aberration test, the firmness test and the area of black spot on the banana skin. The results showed that high dosages of UV-C damaged the banana skin, while low dosages were more efficient at delaying changes in the relative brightness of the skin. The maximum UV-C treatment dose for satisfactory banana preservation was between 21 and 24 μW/cm2. These results could help to improve the visual quality of bananas and to classify their ripeness more easily.

  4. A Rudimentary Optical System in Detecting Ripeness of Red Watermelon

    Science.gov (United States)

    Ezan Abdullah, Noor; Hashim, Hadzli; Fathullah Sulaiman, Muhammad; Korlina Madzhi, Nina; Faiz Mohd Sampian, Ahmad; Aima Ismail, Faridatul

    2015-11-01

    The purpose of this project is to detect the ripeness and quality of the watermelon particularly for red watermelon. The ripeness of the watermelon will be evaluated by using near-infrared spectroscopy sensor (NRIS). The color wavelength will classify the ripeness of the watermelon. An infrared light will be used to get the appropriate wavelength from the watermelon either from the rind or inner of it and the signal received will be analyzed. An appropriate algorithm is used to extract the information of the inner of the watermelon. A microcontroller namely Programmable Interface Controller (PIC) will be used to execute the algorithm and the result will be displayed on Liquid Crystal Display (LCD). Based on the result obtain from the device, the data is computed by using Statistical Package for the Social Sciences (SPSS). This approach is vital to verify the relationship between unripe and ripeness of red watermelon. The objective of this project is to produce an efficient system to detect the ripeness of the watermelon.

  5. Ripeness sensor development. Final report of a Phase 2 study

    Energy Technology Data Exchange (ETDEWEB)

    Stroshine, R.

    1995-08-01

    This is a final report for the Phase II study entitled ``Ripeness Sensor Development.`` The overall objective of the study was the development of a prototype device capable of testing whole fruits for sugar content. Although ripeness and sugar content are not synonymous, they are closely related. Furthermore, the consumer`s acceptance of or preference for fruits is strongly influenced by sugar content. Therefore, the device was called a ripeness sensor. The principle behind the measurement is proton magnetic resonance ({sup 1}H-MR). For several decades, chemists, pharmacists and other scientists have been using {sup 1}H-MR to investigate chemical structure and composition. More recently, the technique has been used in laboratories of the food industry for quality control. This effort represents one of the first attempts to adapt {sup 1}H-MR to use in a commercial facility. 28 refs., 36 figs., 7 tabs.

  6. Spectral Image Analysis for Measuring Ripeness of Tomatoes

    NARCIS (Netherlands)

    Polder, G.; Heijden, van der G.W.A.M.; Young, I.T.

    2002-01-01

    In this study, spectral images of five ripeness stages of tomatoes have been recorded and analyzed. The electromagnetic spectrum between 396 and 736 nm was recorded in 257 bands (every 1.3 nm). Results show that spectral images offer more discriminating power than standard RGB images for measuring r

  7. Determination of ripeness stages of Mazafati variety of date fruit by Raman spectroscopy

    Directory of Open Access Journals (Sweden)

    R Khodabakhshian

    2016-04-01

    Full Text Available Introduction: The economical yield of date fruits depends on many factors (Al-Shahib and Marshall, 2003. One of them is harvesting in optimum stage. Generally, date fruits have four distinct stages of ripeness to satisfy different consumption requirements (e.g., fresh and processed. They are known throughout the world by their Arabic names which are Kimri, Khalal, Rutab and Tamr in order of ripeness (Imad and Abdul Wahab, 1995; Al-Shahib and Marshall, 2003; Sahari et al., 2007. Decreasing moisture content and increasing sugar content happens gradually while the date ripeness approaches to Tamr stage. From Kimri to Khalal stage, the size and acidity decreases when the color of Mazafati variety changes from green to red. The change in acidity continues from Rutab to Tamr stage while color transforms from brown to black. At the final stage of ripeness, Mazafati variety is soft and has a good storability (Al-Shahib and Marshall, 2003. The main Raman techniques commonly applied in agricultural product and food analyzing include dispersive Raman spectroscopy, Fourier Transform (FT, Raman spectroscopy, Surface-Enhanced Raman Spectroscopy (SERS and Spatially Offset Raman Spectroscopy (SORS. Synytsya et al. (2003 illustrated that FT-Raman spectroscopy is a valuable tool in structural analysis of commercial citrus and sugar beet pectin. Yang and Irudayaraj (2003 employed an FT-Raman approach to detect and classify foodborne microorganisms on the whole apple surface for the first time. Schulz et al., (2005 revealed the potential of FT-Raman spectroscopy in natural carotenoid analysis. Also, many researchers have attempted to apply FT-Raman spectra on the whole fruits and vegetables. FT-Raman spectroscopy was used by Veraverbeke et al. (2005 to evaluate the natural, intact wax layers on the surface of whole fruits. Nikbakht et al. (2011 used a FT-Raman spectroscopy for qualitative and quantitative analysis of tomato ripeness parameters. The scope of this

  8. Developmentally regulated sesquiterpene production confers resistance to Colletotrichum gloeosporioides in ripe pepper fruits.

    Directory of Open Access Journals (Sweden)

    Sangkyu Park

    Full Text Available Sesquiterpenoid capsidiol, exhibiting antifungal activity against pathogenic fungus, is accumulated in infected ripe pepper fruits. In this study, we found a negative relation between the capsidiol level and lesion size in fruits infected with Colletotrichum gloeosporioides, depending on the stage of ripening. To understand the developmental regulation of capsidiol biosynthesis, fungal-induced gene expressions in the isoprenoid biosynthetic pathways were examined in unripe and ripe pepper fruits. The sterol biosynthetic pathway was almost shut down in healthy ripe fruits, showing very low expression of hydroxymethyl glutaryl CoA reductase (HMGR and squalene synthase (SS genes. In contrast, genes in the carotenoid pathway were highly expressed in ripe fruits. In the sesquiterpene pathway, 5-epi-aristolochene synthase (EAS, belonging to a sesquiterpene cyclase (STC family, was significantly induced in the ripe fruits upon fungal infection. Immunoblot and enzyme activity analyses showed that the STCs were induced both in the infected unripe and ripe fruits, while capsidiol was synthesized discriminatively in the ripe fruits, implying diverse enzymatic specificity of multiple STCs. Thereby, to divert sterol biosynthesis into sesquiterpene production, infected fruits were pretreated with an SS inhibitor, zaragozic acid (ZA, resulting in increased levels of capsidiol by more than 2-fold in the ripe fruits, with concurrent reduction of phytosterols. Taken together, the present results suggest that the enhanced expression and activity of EAS in the ripe fruits play an important role in capsidiol production, contributing to the incompatibility between the anthracnose fungus and the ripe pepper fruits.

  9. Differentiation of degrees of ripeness of Catuai and Tipica green coffee by chromatographical and statistical techniques.

    Science.gov (United States)

    Smrke, Samo; Kroslakova, Ivana; Gloess, Alexia N; Yeretzian, Chahan

    2015-05-01

    The quality of green coffee is influenced by the degree of ripeness of the fruit at harvest. The aim of this study was to identify chemical markers differentiating between degrees of ripeness. Two coffee varieties, Catuai and Tipica, from the same farm were analysed using the following parameters and methods: caffeine and chlorogenic acid content using high-performance liquid chromatography (HPLC), sucrose content using hydrophilic interaction chromatography, high-molecular weight fraction (HMW) using high-performance size-exclusion chromatography (HPSEC) and volatile compounds using headspace solid phase micro extraction gas chromatography/mass spectrometry. The best method for differentiating between degrees of ripeness was found to be principal component analysis (PCA) based on HPLC data. HPSEC showed differences in the HMW fraction for different degrees of ripeness and both coffee varieties. Volatile profiles allowed separation of both varieties; yet, except for ripe Catuai, no separation was achieved for the degree of ripeness.

  10. Effect of ripeness and postharvest storage on the phenolic profiles of cherries (Prunus avium L.)

    DEFF Research Database (Denmark)

    Goncalves, B.; Landbo, Anne-Katrine Regel; Knudsen, D.;

    2004-01-01

    The phenolic compounds hydroxycinnamates, anthocyanins, flavonols, and flavan-3-ols of sweet cherry cultivars Burial, Saco, Summit, and Van harvested in 2001 and 2002 were quantified by HPLC-DAD. Phenolics were analyzed at partially ripe and ripe stages and during storage at 15+/-5 degreesC (room...

  11. An R2R3-MYB Transcription Factor Regulates Eugenol Production in Ripe Strawberry Fruit Receptacles

    NARCIS (Netherlands)

    Medina-Puche, L.; Molina-Hidalgo, F.J.; Boersma, M.; Schuurink, R.C.; López-Vidriero, I.; Solano, R.; Franco-Zorrilla, J.M.; Caballero, J.L.; Blanco-Portales, R.; Muñoz-Blanco, J.

    2015-01-01

    Eugenol is a volatile phenylpropanoid that contributes to flower and ripe fruit scent. In ripe strawberry (Fragaria x ananassa) fruit receptacles, eugenol is biosynthesized by eugenol synthase (FaEGS2). However, the transcriptional regulation of this process is still unknown. We have identified and

  12. Portable equipment for determining ripeness in Hass avocado using a low cost color sensor

    Science.gov (United States)

    Toro, Jessica; Daza, Carolina; Vega, Fabio; Diaz, Leonardo; Torres, Cesar

    2015-08-01

    The avocado is a one climacteric fruit that not ripe on the tree because it produces a maturation inhibitor that passes the fruit through the pedicel, the ripening occurs naturally during storage or to be induced as required. In post-harvest ripening stage is basically determined by experience of the farmer or buyer. In this word us developed portable equipment for determining ripeness is hass avocado using a low cost sensor color sensor TC3200 and LCD for display result. The prototype read of RGB color frequencies of the sensor and estimates the stage of ripeness in fourth different stages in post-harvest ripening.

  13. Characterization of bioactive compounds from raw and ripe Mangifera indica L. peel extracts.

    Science.gov (United States)

    Ajila, C M; Rao, L Jaganmohan; Rao, U J S Prasada

    2010-12-01

    Mango is one of the important tropical fruits in the world. As it is a seasonal fruit, it is processed for various products. During its processing, peel is one of the major byproducts, which is being wasted. Bioactive conserves were extracted using 80% acetone from peels of raw and ripe mango fruits and subjected to acid hydrolysis. The prominent phenolic compounds identified by HPLC were protocatechuic acid, gentisic acid and gallic acid. The phenolic acid derivatives present in acetone extracts of raw and ripe peels were tentatively identified by LC-MS. Gallic acid, syringic acid, mangiferin, ellagic acid, gentisyl-protocatechuic acid, quercetin were the phenolic compounds identified in both raw and ripe peels, while raw peel showed the presence of glycosylated iriflophenone and maclurin derivatives also. β-Carotene was the major carotenoid followed by violaxanthin and lutein. Thus, both raw and ripe mango peel extracts have different phenolic compounds and carotenoids, which will have various pharmaceutical applications.

  14. Determination of ripeness stages of Mazafati variety of date fruit by Raman spectroscopy

    OpenAIRE

    R Khodabakhshian; B Emadi

    2016-01-01

    Introduction: The economical yield of date fruits depends on many factors (Al-Shahib and Marshall, 2003). One of them is harvesting in optimum stage. Generally, date fruits have four distinct stages of ripeness to satisfy different consumption requirements (e.g., fresh and processed). They are known throughout the world by their Arabic names which are Kimri, Khalal, Rutab and Tamr in order of ripeness (Imad and Abdul Wahab, 1995; Al-Shahib and Marshall, 2003; Sahari et al., 2007). Decreasing ...

  15. Characterization of polyphenolic constituents and radical scavenging ability of ripe tomato and red pepper fruits

    Directory of Open Access Journals (Sweden)

    Seun F. Akomolafe

    2015-03-01

    Full Text Available Objective: Characterization of polyphenolic contents and the inhibitory effects of aqueous extracts of ripe tomato (Lycopersicon esculentum and red pepper (Capsicum annuum fruits on the sodium nitroprusside (SNP and iron(II (Fe2+-induced lipid peroxidation in rat liver were examined in this study. Methods: Various experimental models such as the ABTS and #8226; (2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid scavenging ability and ferric reducing power were used to characterize the antioxidant activity of the extracts. High-performance liquid chromatography (HPLC was used to determine the phenolic content of the extracts. Malondialdehyde (MDA was used as a measure of oxidative stress in the rat and #8217;s liver tissue. Results: The ABTS and #8226; scavenging ability and ferric reducing power of the aqueous extract of ripe red pepper were significantly higher than that of ripe tomato. Ripe red pepper and tomato fruits extracts inhibited NO and #8226; in a concentration dependent manner. Furthermore, the introduction of extracts of ripe red pepper and tomato caused a significant concentration-dependent decrease in the MDA content of the SNP and Fe2+-stressed liver homogenates. In addition, HPLC analyses of the extracts revealed the presence of different phenolic compounds. Conclusion: With respect to the results of the current study, ripe tomato and red pepper could be considered to be potential sources of natural antioxidants. [J Exp Integr Med 2015; 5(1.000: 61-67

  16. Intelligent Color Vision System for Ripeness Classification of Oil Palm Fresh Fruit Bunch

    Directory of Open Access Journals (Sweden)

    Haidi Ibrahim

    2012-10-01

    Full Text Available Ripeness classification of oil palm fresh fruit bunches (FFBs during harvesting is important to ensure that they are harvested during optimum stage for maximum oil production. This paper presents the application of color vision for automated ripeness classification of oil palm FFB. Images of oil palm FFBs of type DxP Yangambi were collected and analyzed using digital image processing techniques. Then the color features were extracted from those images and used as the inputs for Artificial Neural Network (ANN learning. The performance of the ANN for ripeness classification of oil palm FFB was investigated using two methods: training ANN with full features and training ANN with reduced features based on the Principal Component Analysis (PCA data reduction technique. Results showed that compared with using full features in ANN, using the ANN trained with reduced features can improve the classification accuracy by 1.66% and is more effective in developing an automated ripeness classifier for oil palm FFB. The developed ripeness classifier can act as a sensor in determining the correct oil palm FFB ripeness category.

  17. Influence of the fruit's ripeness on virgin olive oil quality.

    Science.gov (United States)

    Franco, Ma Nieves; Sánchez, Jacinto; De Miguel, Concepción; Martínez, Manuel; Martín-Vertedor, Daniel

    2015-01-01

    Virgin Olive Oil (VOO) is a product much demanded by consumers looking for the highest quality and certain traits considered to be typical of the Mediterranean area. The olive fruit's properties and the industry-regulated physicochemical and sensory parameters of seven cultivars were evaluated during the ripening process. In general, the oil percentage in both the wet and dry material increased for all the cultivars from the green to the spotted stages of maturation, and they stayed constant statistically until the ripe stage with just a few exceptions. The lowest oil content was observed in the Manzanilla Cacereña cultivar in all stages of maturation. The cultivars that presented the lowest oil yields in the Abencor system were Manzanilla Cacereña and Carrasqueña, and the highest Corniche. In general, all the cultivars except one presented good behaviour during the mixing process, the exception being Manzanilla Cacereña which presented the lowest values of the extractability percentage. The moisture content of the olives presented a common pattern, increasing from the green to the spotted stage, with the differences being significant in the Corniche, Picual, and Verdial de Badajoz cultivars. All the oils analysed were classified into the "extra virgin" category according to the results for the regulated parameters. The fruity, bitter, and pungent attributes decreased during ripening in all the cultivars studied. In the green stage of maturation, Arbequina had the least intensity of bitterness and pungency, but there were no significant differences among cultivars in the fruity attribute.

  18. Comparison of pancreatic lipase inhibitory isoflavonoids from unripe and ripe fruits of Cudrania tricuspidata

    Science.gov (United States)

    Jo, Yang Hee; Kim, Seon Beom; Liu, Qing; Do, Seon-Gil; Hwang, Bang Yeon

    2017-01-01

    The composition and content of the active constituents and their biological activity vary according to diverse factors including their maturation stages. A previous study showed that the fruits of Cudrania tricuspidata inhibited pancreatic lipase activity, a key enzyme in fat absorption. In this study, we investigated the chemical composition and pancreatic lipase inhibitory activity of unripe and ripe fruits of C. tricuspidata. Unripe fruits of C. tricuspidata have a higher content of total phenolic and flavonoids and exhibited stronger pancreatic lipase inhibition compared to ripe fruits. HPLC analysis revealed the different chemical compositions of the unripe and ripe fruits. Further fractionation resulted in the isolation of 30 compounds including two new isoflavonoids. Analysis of the chemical constituents of the unripe and ripe fruits revealed that a 2,2-dimethylpyran ring, a cyclized prenyl, was the predominant side chain in the unripe fruits, whereas it was a linear prenyl group in the ripe fruits. In addition, a new isoflavonoid (19) from the unripe fruits showed the most potent inhibition on pancreatic lipase. Taken together, the maturation stage is an important factor for maximum efficacy and that unripe fruits of C. tricuspidata are a good source of new bioactive constituents for the regulation of obesity PMID:28253267

  19. Influence of Ripeness and Drying Process on the Polyphenols and Tocopherols of Pistacia vera L.

    Directory of Open Access Journals (Sweden)

    Gabriele Ballistreri

    2009-10-01

    Full Text Available This paper highlights, for the first time, the changes in the phenolics fraction (anthocyanins, flavonoids and stilbenes and tocopherols of unpeeled Pistacia vera L. var. bianca with ripening, and the effect of the sun-drying process. The total polyphenol levels in pistachios, measured as mg of Gallic Acid Equivalent (GAE, were: 201 ± 10.1, 349 ± 18.3 and 184.7 ± 6.2 mg GAE/100 g DM in unripe, ripe and dried ripe samples, respectively. Most phenolics in ripe pistachios were found to be anthocyanins. They increased with ripening, while the sun drying process caused a susbtantial loss. Flavonoids found in all pistachio samples were daidzein, genistein, daidzin, quercetin, eriodictyol, luteolin, genistin and naringenin, which decreased both with ripening and drying. Before the drying process both unripe and ripe pistachios showed a higher content of trans-resveratrol than dried ripe samples. γ-Tocopherol was the major vitamin E isomer found in pistachios. The total content (of α- and γ-tocopherols decreased, both during ripening and during the drying process. These results suggested that unpeeled pistachios can be considered an important source of phenolics, particularly of anthocyanins. Moreover, in order to preserve these healthy characteristics, new and more efficient drying processes should be adopted.

  20. Enhanced Machine Vision System for Ripe Fruit Detection Based on Robotic Harvesting

    Directory of Open Access Journals (Sweden)

    R. Thendral

    2015-04-01

    Full Text Available The proposed work intends to provide an efficient algorithm for the instruction of an automatic robot arm to choose the ripe fruits on the tree. Steps involved in this study are recognizing and locating the ripe fruits from the leaf and branch portions by using an efficient machine vision algorithm. Initially, discrete wavelet transform is used for better preserving of edges and fine details in the given input image. Then RGB, HSV, L*a*b* and YIQ color spaces were studied to segment the ripe fruits from the surrounding objects. Finally, the results showed that ‘I’ component of the YIQ color space has the best criterion for recognizing the fruit from the foliage. The fruit segmentation based on machine vision has an occlusion problem. In this proposed method these problems are also examined.

  1. Artificial vision system for the identification of ripeness of pasion fruit (granadilla

    Directory of Open Access Journals (Sweden)

    Diego Escobar Figueroa

    2016-06-01

    Full Text Available The proper handling of fruits has become one of the most important economic activities in the Colombian agriculture [1]. Actually, the identification of the ripeness of fruit is made manually [2], which induces variability due to subjectivity by expert eye strain. The purpose of this research was to develop a computational tool for identifying the state of ripeness of passion fruit (granadilla through images recognition. The area in pixels of the fruit images was extracted by a technique called Otsu, using OpenCv libraries in Python. Finally, the task of classification was conducted through cluster analysis, here were assigned 110 points RGB belonging to each state of maturity of passion fruit. The results showed 92, 6% of accuracy for identifying the state of ripeness, from a set of 90 images obtained from 90 fruits in different stages of maturity, which was compared with traditional analysis (conducted by experts according to the provisions of the Colombian Technical Standard NTC 4101.

  2. Non-destructive Ripeness Sensing by Using Proton NMR [Nuclear Magnetic Resonance

    Science.gov (United States)

    Cho, Seong In; Krutz, G. W.; Stroshine, R. L.; Bellon, V.

    1990-01-01

    More than 80 kinds of fruits and vegetables are available in the United States. But only about 6 of them have their quality standards (Dull, 1986). In the 1990 Fresh Trends survey (Zind, 1990), consumers were asked to rate 16 characteristics important to their decision to purchase fresh produce. The four top ranking factors were ripeness/freshness, taste/flavor, appearance/condition and nutritional value. Of these surveyed, 96% rated ripeness/freshness as extremely important or very important. Therefore, the development of reliable grading or sorting techniques for fresh commodities is essential. Determination of fruit quality often involves cutting and tasting. Non-destructive quality control in fruit and vegetables is a goal of growers and distributors, as well as the food processing industry. Many nondestructive techniques have been evaluated including soft x-ray, optical transmission, near infrared radiation, and machine vision. However, there are few reports of successful non-destructive measurement of sugar content directly in fruit. Higher quality fruit could be harvested and available to consumers if a nondestructive sensor that detects ripeness level directly by measuring sugar content were available. Using proton Nuclear Magnetic Resonance (NMR) principle is the possibility. A nondestructive ripeness (or sweetness) sensor for fruit quality control can be developed with the proton NMR principle (Cho, 1989). Several feasibility studies were necessary for the ripeness sensor development. Main objectives in this paper was to investigate the feasibilities (1) to detect ripeness (or sweetness level) of raw fruit tissue with an high resolution proton NMR spectroscopy (200 MHz) and (2) to measure sugar content of intact fruit with a low resolution proton NMR spectroscopy (10 MHz).

  3. 响应面法优化白英生物碱的超声提取工艺条件%Optimization of Ultrasonic Extraction of NIGHTSHADE Alkalolds by Response Surface Method

    Institute of Scientific and Technical Information of China (English)

    陆文总; 贾光锋; 孟祥艳; 赵晨; 倪原

    2012-01-01

    [目的]优选白英生物碱的最佳超声提取工艺条件.[方法]在单因素试验的基础上,选择超声时间、温度、料液比为自变量,以生物碱提取率为响应值,采用中心组合设计的方法,研究各自变量及其交互作用对生物碱提取率的影响.利用响应面分析方法,模拟得到二次回归方程的预测函数,并确定白英生物碱提取工艺的最适条件.[结果]最佳提取工艺条件为:超声时间53 min、温度65℃、料液比1∶20(g/ml)、提取2次;在此条件下,生物碱提取率达0.308%.[结论]该方法优选了白英生物碱的最佳超声提取工艺条件,为白英的进一步开发利用提供了依据.%[Objective] To optimize the extraction conditions for the ultrasonic extraction of alkaloids from NIGHTSHADE. [Mehod] Based on single factor test,the ultrasonic time,temperature and solid-liquid ratio were selected as the independent variables. With the extraction rate of alkaloids as the response value,Central Composite Design was adopted to research on the effects of independent variables and their overlapping effects on the extraction rate of alkaloids. Predictive function of quadratic regression equation was obtained by response surface method. And the optimal extraction condition for alkaloids from NIGHTSHADE was obtained. [ Result] The optimal extraction condition was as follows; S3 nun extraction time,65 ℃ extraction temperature,1:20(g/ml) solid-liquid ratio,and 2 extraction times. Under this condition,the extraction rate of alkaloids from NIGHTSHADE reached 0. 308%. [Conclusion] The optima) extraction condition for alkaloids from NIGHTSHADE was obtained, which provided references for the further development and utilization of NIGHTSHADE.

  4. Kitchen practices impact on volatile flavors in ripe tomatoes: effects of refrigeration and blanching

    Science.gov (United States)

    Both blanching and refrigeration of ripe tomatoes are common practices in kitchen and food service prior to being sliced. However, little is reported on the impact of such treatments on volatile profiles in tomato fruit. In this study, ‘FL 47’ tomatoes at full red stage were dipped in 52 °C hot wate...

  5. Application of multispectral imaging to determine quality attributes and ripeness stage in strawberry fruit.

    Directory of Open Access Journals (Sweden)

    Changhong Liu

    Full Text Available Multispectral imaging with 19 wavelengths in the range of 405-970 nm has been evaluated for nondestructive determination of firmness, total soluble solids (TSS content and ripeness stage in strawberry fruit. Several analysis approaches, including partial least squares (PLS, support vector machine (SVM and back propagation neural network (BPNN, were applied to develop theoretical models for predicting the firmness and TSS of intact strawberry fruit. Compared with PLS and SVM, BPNN considerably improved the performance of multispectral imaging for predicting firmness and total soluble solids content with the correlation coefficient (r of 0.94 and 0.83, SEP of 0.375 and 0.573, and bias of 0.035 and 0.056, respectively. Subsequently, the ability of multispectral imaging technology to classify fruit based on ripeness stage was tested using SVM and principal component analysis-back propagation neural network (PCA-BPNN models. The higher classification accuracy of 100% was achieved using SVM model. Moreover, the results of all these models demonstrated that the VIS parts of the spectra were the main contributor to the determination of firmness, TSS content estimation and classification of ripeness stage in strawberry fruit. These results suggest that multispectral imaging, together with suitable analysis model, is a promising technology for rapid estimation of quality attributes and classification of ripeness stage in strawberry fruit.

  6. Low temperature-induced lycopene degradaton in red ripe tomato evaluated by remittance spectroscopy

    NARCIS (Netherlands)

    Farneti, B.; Schouten, R.E.; Woltering, E.J.

    2012-01-01

    Tomatoes are mostly harvested at the orange and red-ripe stages. A survey among consumers indicated that tomatoes are most often stored in the refrigerator well below 10 °C, a temperature considered harmful for chilling sensitive products such as tomato. Also during distribution, tomatoes may be exp

  7. 7 CFR 932.150 - Modified minimum quality requirements for canned green ripe olives.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Modified minimum quality requirements for canned green... (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts... requirements for canned green ripe olives. The minimum quality requirements prescribed in § 932.52 (a)(1)...

  8. The Alpha and Omega Syndrome: Is Intra-District Funding the next Ripeness Factor?

    Science.gov (United States)

    Owings, William A.; Kaplan, Leslie S.

    2010-01-01

    Fiscal disparities within school districts may be the next area "ripe" for litigation. Equity and adequacy litigation have largely focused on between-district fiscal disparities. Research suggests that within-district disparities may be as unfair to high poverty schools. When the school funding pie is not growing, remedying…

  9. An R2R3-MYB Transcription Factor Regulates Eugenol Production in Ripe Strawberry Fruit Receptacles.

    Science.gov (United States)

    Medina-Puche, Laura; Molina-Hidalgo, Francisco Javier; Boersma, Maaike; Schuurink, Robert C; López-Vidriero, Irene; Solano, Roberto; Franco-Zorrilla, José-Manuel; Caballero, José Luis; Blanco-Portales, Rosario; Muñoz-Blanco, Juan

    2015-06-01

    Eugenol is a volatile phenylpropanoid that contributes to flower and ripe fruit scent. In ripe strawberry (Fragaria × ananassa) fruit receptacles, eugenol is biosynthesized by eugenol synthase (FaEGS2). However, the transcriptional regulation of this process is still unknown. We have identified and functionally characterized an R2R3 MYB transcription factor (emission of benzenoid II [FaEOBII]) that seems to be the orthologous gene of PhEOBII from Petunia hybrida, which contributes to the regulation of eugenol biosynthesis in petals. The expression of FaEOBII was ripening related and fruit receptacle specific, although high expression values were also found in petals. This expression pattern of FaEOBII correlated with eugenol content in both fruit receptacle and petals. The expression of FaEOBII was repressed by auxins and activated by abscisic acid, in parallel to the ripening process. In ripe strawberry receptacles, where the expression of FaEOBII was silenced, the expression of cinnamyl alcohol dehydrogenase1 and FaEGS2, two structural genes involved in eugenol production, was down-regulated. A subsequent decrease in eugenol content in ripe receptacles was also observed, confirming the involvement of FaEOBII in eugenol metabolism. Additionally, the expression of FaEOBII was under the control of FaMYB10, another R2R3 MYB transcription factor that regulates the early and late biosynthetic genes from the flavonoid/phenylpropanoid pathway. In parallel, the amount of eugenol in FaMYB10-silenced receptacles was also diminished. Taken together, these data indicate that FaEOBII plays a regulating role in the volatile phenylpropanoid pathway gene expression that gives rise to eugenol production in ripe strawberry receptacles.

  10. The chemical investigations on the ripe fruits of Ammi visnaga (Lam.) Lamarck growing in Turkey.

    Science.gov (United States)

    Günaydin, Keriman; Beyazit, Neslihan

    2004-04-01

    Two furanochromones and one furanochromone glycoside were isolated from the fruits of Ammi visnaga (L.) Lam. They were identified as khellin, visnagin, and khellol glycoside by interpretation of spectral analyses. Quantitative determination of furanochromones in A. visnaga (L.) ripe fruits from Hatay region (Turkey) was carried out by ultraviolet spectrophotometry and gas chromatography. In addition, photochemical properties of furanochromones and chemical composition of essential oil were determined.

  11. Characterization of polyphenolic constituents and radical scavenging ability of ripe tomato and red pepper fruits

    OpenAIRE

    Akomolafe, Seun F.; Ganiyu Oboh

    2015-01-01

    Objective: Characterization of polyphenolic contents and the inhibitory effects of aqueous extracts of ripe tomato (Lycopersicon esculentum) and red pepper (Capsicum annuum) fruits on the sodium nitroprusside (SNP) and iron(II) (Fe2+)-induced lipid peroxidation in rat liver were examined in this study. Methods: Various experimental models such as the ABTS and #8226; (2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) scavenging ability and ferric reducing power were used to character...

  12. Methylenebisnicotiflorin: a rare methylene-bridged bisflavonoid glycoside from ripe Pu-er tea.

    Science.gov (United States)

    Tao, Mu-Ke; Xu, Min; Zhang, Han; Chen, Hui; Liu, Chang; Zhu, Hong-Tao; Wang, Dong; Yang, Chong-Ren; Zhang, Ying-Jun

    2016-01-01

    A new methylene-bridged dimeric flavonol glycoside, methylenebisnicotiflorin (1), was isolated from ripe Pu-er tea, along with 10 known flavonoids (2-11) and seven known phenolic compounds (12-18). The structure elucidation was based on spectroscopic analysis. Among them, 1,3-dihydroxyphenyl-2-O-sulfate (13), 2,3,4-trihydroxybenzoic acid (16) and 3,3',4,4'-tetrahydroxybiphenyl (18) are reported from tea plants for the first time.

  13. Spatio-temporal complexity of chimpanzee food: How cognitive adaptations can counteract the ephemeral nature of ripe fruit.

    Science.gov (United States)

    Janmaat, Karline R L; Boesch, Christophe; Byrne, Richard; Chapman, Colin A; Goné Bi, Zoro B; Head, Josephine S; Robbins, Martha M; Wrangham, Richard W; Polansky, Leo

    2016-06-01

    Ecological complexity has been proposed to play a crucial role in primate brain-size evolution. However, detailed quantification of ecological complexity is still limited. Here we assess the spatio-temporal distribution of tropical fruits and young leaves, two primary chimpanzee (Pan troglodytes) foods, focusing on the predictability of their availability in individual trees. Using up to 20 years of information on monthly availability of young leaf, unripe and ripe fruit in plant species consumed by chimpanzees from tropical forests in East, Central, and West Africa, we estimated: (1) the forest-wide frequency of occurrence of each food type and (2) the predictability of finding ripe fruit-bearing trees, focusing on the timing, frequency, and amount of ripe fruit present. In all three forests, at least half of all encountered trees belonged to species that chimpanzees were known to feed on. However, the proportion of these trees bearing young leaves and fruit fluctuated widely between months. Ripe fruit was the most ephemeral food source, and trees that had more than half of their crown filled were at least nine times scarcer than other trees. In old growth forests only one large ripe fruit crop was on average encountered per 10 km. High levels of inter-individual variation in the number of months that fruit was present existed, and in some extreme cases individuals bore ripe fruit more than seven times as often as conspecifics. Some species showed substantially less variation in such ripe fruit production frequencies and fruit quantity than others. We hypothesize that chimpanzees employ a suite of cognitive mechanisms, including abilities to: (1) generalize or classify food trees; (2) remember the relative metrics of quantity and frequency of fruit production across years; and (3) flexibly plan return times to feeding trees to optimize high-energy food consumption in individual trees, and efficient travel between them. Am. J. Primatol. 78:626-645, 2016. © 2016

  14. Caavuranamide, a novel steroidal alkaloid from the ripe fruits of Solanum caavurana Vell. (Solanaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Vaz, Nelissa Pacheco; Santos, Erica L.; Marques, Francisco A.; Maia, Beatriz H.L.N. Sales, E-mail: noronha@ufpr.br [Departamento de Quimica, Universidade Federal do Parana, Centro Politecnico, Curitiba, PR (Brazil); Costa, Emmanoel V. [Departamento de Quimica, Universidade Federal de Sergipe, Sao Cristovao, SE (Brazil); Mikich, Sandra Bos [Laboratorio de Ecologia, Embrapa Florestas, Colombo, PR (Brazil); Braga, Raquel M. [Instituto de Quimica, Universidade Estadual de Campinas, SP (Brazil); Delarmelina, Camila; Duarte, Marta C.T. [Divisao de Microbiologia, Centro Pluridisciplinar de Pesquisas Quimicas Biologicas e Agricolas (CPQBA), Universidade Estadual de Campinas, SP (Brazil); Duarte, Marta C.T.; Ruiz, Ana Lucia T.G.; Souza, Vanessa H.S.; Carvalho, Joao E. de [Divisa de Farmacologia e Toxicologia, Centro Pluridisciplinar de Pesquisas Quimicas Biologicas e Agricolas (CPQBA), Universidade Estadual de Campinas, SP (Brazil)

    2012-07-01

    Phytochemical investigation of the ripe fruits of Solanum caavurana Vell. (Solanaceae) afforded a novel steroidal alkaloid with spirosolane-type skeleton, named as caavuranamide, together with the alkaloids 4-tomatiden-3-one and 5{alpha}-tomatidan-3-one. Their structures were elucidated on the basis of spectroscopic methods. The antiproliferative and antimicrobial activities for the ethanolic extract, sub-fractions obtained from partition and acid-base treatment were also evaluated. Caavuranamide showed antibacterial activity similar to the chloramphenicol positive control against Rhodococcus equi. (author)

  15. Acoustic Testing for Melon Fruit Ripeness Evaluation during Different Stages of Ripening

    Directory of Open Access Journals (Sweden)

    Farhad Khoshnam

    2016-05-01

    Full Text Available Non-destructive impulse response technique was tested on two melon varieties (‘Zard-Eyvanekey’ and ‘Sousky-Sabz’ in five different stages of ripening. Resonance frequency and sound pressure level (SPL from the impulse response were compared with mass, elastic modulus, soluble solids contents (TSS and sensory evaluation. Among acoustic and destructive parameters, resonance frequency is an indicator to distinguish of different maturity stage of the melon in both varieties. The sound pressure level (SPL was not a reliable parameter to evaluate melon ripeness. It was established that the impulse response technique is useful to decide fruit maturity stage and appropriate harvest time.

  16. HPLC-DAD Phenolic Characterization and Antioxidant Activities of Ripe and Unripe Sweet Orange Peels

    Science.gov (United States)

    Omoba, Olufunmilayo Sade; Obafaye, Rebeccah Olajumoke; Salawu, Sule Ola; Boligon, Aline Augusti; Athayde, Margareth Linde

    2015-01-01

    Phenolic compounds of unripe and ripe sweet orange peels were determined using a high-performance liquid chromatography separation method with diode array detector (HPLC-DAD). The in vitro antioxidant properties and the EC50 (concentration required to obtain a 50% antioxidant effect) values were also determined. The predominant phenolic compounds were quercitrin, rutin, and quercetin with values of 18.77 ± 0.01 mg/mL, 18.65 ± 0.03 mg/mL, and 10.39 ± 0.01 mg/mL respectively in unripe orange peel and 22.61 ± 0.01 mg/mL, 17.93 ± 0.03 mg/mL, and 14.03 ± 0.02 mg/mL respectively in ripe orange peel. The antioxidant properties revealed 2,2′-azino-bis(3-ethyl benzothiazoline-6-sulfonic acid) diammonium salt (ABTS) scavenging ability of both unripe and ripe orange peels respectively as 14.68 ± 0.01 and 16.89 ± 0.02 mmol TEAC/g, the Ferric Reducing Antioxidant Properties (FRAP) as 70.69 ± 0.01 and 91.38 ± 0.01 mg gallic acid equivalents/100g, total phenol content as 5.27 ± 0.03 and 9.40 ± 0.01 mg gallic acid equivalents/g and total flavonoid content as 3.30 ± 0.30 and 4.20 ± 0.02 mg quercetin equivalent/g. The antioxidant assays showed enhanced potency of extract from ripe orange peel with EC50 values of 2.71 ± 0.03 mg/mL for 2,2-diphenyl-1-picrylhydrazyl (DPPH), 0.67 ± 0.03 mg/mL for hydroxyl radicals (OH*), 0.57 ± 0.02 mg/mL for Fe2+ chelation, and 0.63 ± 0.06 mg/mL for malondialdehyde (MDA), and was more potent than unripe orange peel. PMID:26783839

  17. Cellulase occurs in multiple active forms in ripe avocado fruit mesocarp.

    Science.gov (United States)

    Kanellis, A K; Kalaitzis, P

    1992-02-01

    The existence of multiple forms of avocado (Persea americana Mill. cv Hass) cellulase in crude protein extracts of ripe avocado fruit is reported. Cellulase was separated into at least 11 multiple forms by native isoelectric focusing in the pH range between 4 and 7 and visualized by both activity staining using Congo red and immunostaining. The enzyme components were acidic proteins with isoelectric points in the range of pH 5.10 to 6.80, the predominant forms having isoelectric points of 5.60, 5.80, 5.95, and 6.20. All 11 forms were immunologically related with molecular masses of 54 kilodaltons.

  18. Chemical Composition and Antimicrobial Activity of Leaf, Ripe and Unripe Peel of Bitter Orange (Citrus aurantium Essential Oils

    Directory of Open Access Journals (Sweden)

    Fatemeh Azhdarzadeh

    2016-02-01

    Full Text Available Background and Objectives: The chemical composition and antimicrobial activity of bitter orange (Citrus aurantium leaf, ripe and unripe peel essential oils, cultivated in southwest of Iran, were investigated. Materials and Methods: The analysis of chemical composition of hydro-distilled essential oils was carried out by GC-MS. The disc diffusion and broth micro-dilution were used to assay the antimicrobial effect of achieved essential oils. Results: According to the GC-MS analysis, 34, 39 and 21 components were determined in the leaf, ripe and unripe peel, respectively. The results revealed that the main components of all essential oils were linalool and limonene. The oxygenated monoterpene and hydrocarbonated monoterpene were the main chemical groups of leaf and peel essential oils, respectively. Although all of the examined essential oils had antimicrobial potential, the leaf and unripe peel essential oils with MIC of 4.67 mg/ml were the most effective against the bacteria and yeast species, respectively, and the ripe peel essential oil was the weakest one. The growth of Saccharomyces cerevisiae was controlled in the treated orange juices. The antifungal activity of essential oils was increased by rising up in their concentration and decreased by passing time. Unripe and ripe essential oils showed the strongest and weakest anti yeast potential, respectively. Conclusions: The essential oils of leaves and ripe and unripe peels of bitter orange could be used as natural preservatives in food industry.

  19. Ultra-portable, wireless smartphone spectrometer for rapid, non-destructive testing of fruit ripeness

    Science.gov (United States)

    Das, Anshuman J.; Wahi, Akshat; Kothari, Ishan; Raskar, Ramesh

    2016-09-01

    We demonstrate a smartphone based spectrometer design that is standalone and supported on a wireless platform. The device is inherently low-cost and the power consumption is minimal making it portable to carry out a range of studies in the field. All essential components of the device like the light source, spectrometer, filters, microcontroller and wireless circuits have been assembled in a housing of dimensions 88 mm × 37 mm × 22 mm and the entire device weighs 48 g. The resolution of the spectrometer is 15 nm, delivering accurate and repeatable measurements. The device has a dedicated app interface on the smartphone to communicate, receive, plot and analyze spectral data. The performance of the smartphone spectrometer is comparable to existing bench-top spectrometers in terms of stability and wavelength resolution. Validations of the device were carried out by demonstrating non-destructive ripeness testing in fruit samples. Ultra-Violet (UV) fluorescence from Chlorophyll present in the skin was measured across various apple varieties during the ripening process and correlated with destructive firmness tests. A satisfactory agreement was observed between ripeness and fluorescence signals. This demonstration is a step towards possible consumer, bio-sensing and diagnostic applications that can be carried out in a rapid manner.

  20. Ultra-portable, wireless smartphone spectrometer for rapid, non-destructive testing of fruit ripeness.

    Science.gov (United States)

    Das, Anshuman J; Wahi, Akshat; Kothari, Ishan; Raskar, Ramesh

    2016-09-08

    We demonstrate a smartphone based spectrometer design that is standalone and supported on a wireless platform. The device is inherently low-cost and the power consumption is minimal making it portable to carry out a range of studies in the field. All essential components of the device like the light source, spectrometer, filters, microcontroller and wireless circuits have been assembled in a housing of dimensions 88 mm × 37 mm × 22 mm and the entire device weighs 48 g. The resolution of the spectrometer is 15 nm, delivering accurate and repeatable measurements. The device has a dedicated app interface on the smartphone to communicate, receive, plot and analyze spectral data. The performance of the smartphone spectrometer is comparable to existing bench-top spectrometers in terms of stability and wavelength resolution. Validations of the device were carried out by demonstrating non-destructive ripeness testing in fruit samples. Ultra-Violet (UV) fluorescence from Chlorophyll present in the skin was measured across various apple varieties during the ripening process and correlated with destructive firmness tests. A satisfactory agreement was observed between ripeness and fluorescence signals. This demonstration is a step towards possible consumer, bio-sensing and diagnostic applications that can be carried out in a rapid manner.

  1. Application of Microwave Moisture Sensor for Determination of Oil Palm Fruit Ripeness

    Science.gov (United States)

    Yeow, You Kok; Abbas, Zulkifly; Khalid, Kaida

    2010-01-01

    This paper describes the development of a low cost coaxial moisture sensor for the determination of moisture content (30 % to 80 % wet-weight basis) of the oil palm fruits of various degree of fruit ripeness. The sensor operating between 1 GHz and 5 GHz was fabricated from an inexpensive 4.1 mm outer diameter SMA coaxial stub contact panel which is suitable for single fruit measurement. The measurement system consists of the sensor and a PC-controlled vector network analyzer (VNA). The actual moisture content was determined by standard oven drying method and compared with predicted value of fruit moisture content obtained using the studied sensor. The sensor was used to monitor fruit ripeness based on the measurement of the phase or magnitude of reflection coefficient and the dielectric measurement software was developed to control and acquire data from the VNA using Agilent VEE. This software was used to calculate the complex relative permittivity from the measured reflection coefficient between 1GHz and 5 GHz.

  2. The formation of polyribosomes during the germination of grains of wheat of different ripeness

    Directory of Open Access Journals (Sweden)

    Stanisław Weidner

    2014-01-01

    Full Text Available The total ribosomal fraction was isolated from whole seedlings from grains of wheat gathered at the milk-, milk-wax and full-ripeness stages. A gradual increase in the amount of the total ribosomal fraction was observed during germination until the 6th day in all of the studied groups. From the 6th to 12th days of germination a decrease in this, fraction was found. In all of these groups polysomes constituted 88-90% of the total ribosomal fraction after 48 hrs of germination. From the 2nd to the 12th day, polysomes made up a decreasing percentage of the total ribosomal fraction. The percentage of polysomes contained in this fraction at the begining (0-24 h as well as at the end (10-12th day of the studied period of germination of immature grains was lower than in mature ones, which is synonymous with a lower level of protein synthesis in their tissues. When the results were calculated per seedling, it was shown that the less mature the grain, the lower the total ribosome content. These results show that grains gathered at full ripeness are the most vigorous.

  3. Comparative GC analyses of ripe fruits, leaves and floral buds essential oils of Tunisian Myrtus communis L.

    Directory of Open Access Journals (Sweden)

    Ahmed Snoussi

    2014-07-01

    Full Text Available The chemical composition of essential oils obtained by hydrodistillation from Tunisian wild growing myrtle ripe fruits, leaves and floral buds was examined by GC and GC-MS. The yields of hydrodistilled oils obtained from different plant parts were: leaves 0.5%, floral buds 0.2% and ripe fruits 0.02%. Significant differences were found in the concentration of main constituents of the oils: α-pinene [48.9% (floral buds, 34.3% (fruits, 23.7% (leaves], 1,8-cineole [15.3% (floral buds, 26.6% (fruits, 61.0% (leaves]. The leaves oil contained less linalool than floral buds and ripe fruits oils. Tunisian myrtle is characterized by the absence of myrtenyl acetate.

  4. A study on the oil palm fresh fruit bunch (FFB) ripeness detection by using Hue, Saturation and Intensity (HSI) approach

    Science.gov (United States)

    Kashfi Shabdin, Muhammad; Shariff, Abdul Rashid Mohamed; Nazrul Azlan Johari, Mohd; Kamilah Saat, Nor; Abbas, Zulkifly

    2016-06-01

    To increase the quality of palm oil means to accurately grade the oil palm fresh fruit bunches (FFB) for processing. In this paper, HSI color model was used to determine the relationship between FFB ’ s color with the underipe and ripe category so that the grading system could be accurately done. From the analysis manipulation, a formula was generated and applied to the data obtained. The by linear regression in the data shows an average success rate at 45% accuracy for oil palm ripeness detection. Artificial Neural Network (ANN) however return a better accuracy result for both underipe and ripe categories which are 60% and 80% respectively. This yield an overall accuracy of 70%. This can be increased more by improving the grading system.

  5. Hypoglycaemic Effects of Dietary Intake of Ripe and Unripe Lycopersicon esculentum (Tomatoes on Streptozotocin-Induced Diabetes Mellitus in Rats

    Directory of Open Access Journals (Sweden)

    A. M. Akinnuga

    2010-01-01

    Full Text Available Ripe and unripe tomatoes have been implicated in prevention of chronic diseases such as cancer probably due to their antioxidant, antibiotic, antifungal and anti-inflammatory properties. Problem statement: This study was designed to investigate whether ripe and unripe tomatoes will have hypoglycaemic effect in a chronic disease such as diabetes mellitus that has been characterized with hyperglycaemia. Approach: Twenty albino Wistar rats were divided into 4 groups (2 control and 2 test groups of 5 rats each. The normal and diabetic control groups were given citrate buffer (intraperitoneally and normal rat chow and 65 mg kg-1 streptozotocin (intraperitoneally and normal rat chow respectively. The test groups were given 65 mg kg-1 streptozotocin via intraperitoneal route and either a mixture of ripe or unripe tomato and normal rat chow. In all groups, the blood samples were obtained at the tail vein of the animals and the fasting blood glucose level were monitored and determined on the 1st, 3rd and 14th day of consumption of different feed combinations. Results: There was significant difference in blood glucose level in animals fed on ripe and unripe Lycopersicon esculentum (tomato compared to the normal and diabetic control groups on the 3rd and 14th day without significant difference on the 1st day. Conclusion: Both high-lycopene ripe tomato and high-tomatine unripe tomato have hypoglycaemic effect in diabetic mellitus at short period of dietary intake therefore this suggest that consumers may benefit by not only eating high-lycopene ripe tomatoes, but also high-tomatine unripe tomatoes.

  6. Black to Black

    DEFF Research Database (Denmark)

    Langkjær, Michael Alexander

    2012-01-01

    ’s a lifestyle I enjoy.” For Monáe, the tuxedo is both working clothes and a superhero uniform. Together with futuristic references to Fritz Lang’s dystopian Metropolis, her trademark starched shirt and tuxedo also recall Weimar and pre-war Berlin. While outwardly dissimilar, Sioux’s and Monáe’s shared black...... suggested that appreciation of the highly personal motives of both Siouxsie Sioux and Janelle Monáe in wearing black may be achieved via analogies with the minimalist sublime of American artists Frank Stella’s and Ad Reinhardt’s black canvasses....

  7. Detecting RAPD Markers Linked to Ripe Rot Resistance Genes in Chinese Wild Vitis

    Institute of Scientific and Technical Information of China (English)

    WANG Yue-jin; XU Yan; ZHANG Jian-xia; ZHOU Peng; WAN Yi-zhen

    2002-01-01

    With F1 individuals of the cross combination 88-110 of 83-4-96 ( V. quinquangularis Rehd. )× Muscat Rose ( V. vinifera L. ), the RAPD marker OPC15-1300 linked to ripe rot ( Gloeosporium fruetigenum Berk. ) resistance genes in Chinese wild Vitis was gained using bulked segregation analysis(BSA). And it was found that OPC15-1300 could be hereditary from the resistant parent (83-4-96) after the marker was tested in 50 F1 plants of the cross combination 88-110, 32 accessions of 8 Chinese wild Vitis species and 14cultivars of V. vinifera L. Also, it has provided a solid basis for molecular marker-assisted selection (MAS)and for possibly cloning disease resistance genes in the future.

  8. Life Cycle Assessment (LCA) used to compare two different methods of ripe table olive processing

    Energy Technology Data Exchange (ETDEWEB)

    Russo, C.; Cappelletti, G. M.; Nicoletti, G. M.

    2010-07-01

    The aim of the present study is to analyze the most common method used for processing ripe table olives: the California style. Life Cycle Assessment (LCA) was applied to detect the hot spots of the system under examination. The LCA results also allowed us to compare the traditional California style, here called method A, with another California style, here called method B. We were interested in this latter method, because the European Union is considering introducing it into the product specification of the Protected Denomination of Origin (PDO) La Bella della Daunia. It was also possible to compare the environmental impacts of the two California style methods with those of the Spanish style method. From the comparison it is clear that method B has a greater environmental impact than method A because greater amounts of water and electricity are required, whereas Spanish style processing has a lower environmental impact than the California style methods. (Author)

  9. Effect of Ripeness and Drying Process on Sugar and Ethanol Production from Giant Reed (Arundo donax L.

    Directory of Open Access Journals (Sweden)

    Egidio Viola

    2015-04-01

    Full Text Available The work highlighted the influence of the water content within the starting biomass, drying procedure and ripeness on the enzymatic digestibility of the giant reed, one of the most suitable nonfood crops for bioenergy and bio-compound production. Fresh green reed was treated as received, while oven-dried green and ripe reed were humidified before the steam explosion pretreatment that was carried out at 210 ℃ for 10 minutes. The exploded biomasses were extracted with water to remove the soluble hemicellulose and potential inhibitors; the insoluble residue was submitted to enzymatic hydrolysis and alcoholic fermentation. The process was evaluated in terms of sugars recovery and ethanol yield. After the sequence of pretreatment, enzymatic hydrolysis and fermentation by Saccharomyces cerevisiae 132 g; 103 g; 162 g of ethanol; and 77 g; 63 g; 92 g of pentosanes were respectively obtained from 1 kgDM of fresh green reed; dried green reed or ripe reed. The ripe reed contains more carbohydrates than the green reed and the resulting sugar and ethanol production was higher, in spite of lower saccharification yield. While drying the fresh biomass is good practice for biomass preservation, it negatively affects the recovery of free sugars and the ethanol production, because of fiber hornification which hinders enzyme access in the hydrolysis step.

  10. Effects of ripeness and cultivar on chemical composition of strawberry (Fragaria×ananassa Duch.) fruits and their suitability for jam production as a stable product at different storage temperatures.

    Science.gov (United States)

    Mazur, Sebastian Piotr; Nes, Arnfinn; Wold, Anne-Berit; Remberg, Siv Fagertun; Martinsen, Berit Karoline; Aaby, Kjersti

    2014-03-01

    Effects of ripeness (nearly ripe, ripe, fully ripe) and cultivar ('Blink', 'Polka' and 'Senga Sengana') on colour and chemical composition of strawberry fruits and their suitability for jam production, evaluated as stability during storage at 4 and 20°C for 3 and 6months, were investigated. Quality traits of fruits and jams were significantly affected by both ripeness stage and cultivar. However, after 6months of storage, particularly at 20°C, the effects of fruit ripeness and cultivar were considerably reduced. During jam storage, anthocyanins, ascorbic acid, chroma and hue were least stable in jams made from the least ripe fruits. Quality traits in jams made from 'Senga Sengana' were best preserved during storage, while quality and chemical composition in jams made from 'Blink' changed the most. In conclusion, fully ripe fruits were best suited for jam processing. Storage at low temperature was preferable and 'Senga Sengana' was the most and 'Blink' the least suitable cultivar for processing.

  11. Rendering the Intractable More Tractable: Tools from Caenorhabditis elegans Ripe for Import into Parasitic Nematodes.

    Science.gov (United States)

    Ward, Jordan D

    2015-12-01

    Recent and rapid advances in genetic and molecular tools have brought spectacular tractability to Caenorhabditis elegans, a model that was initially prized because of its simple design and ease of imaging. C. elegans has long been a powerful model in biomedical research, and tools such as RNAi and the CRISPR/Cas9 system allow facile knockdown of genes and genome editing, respectively. These developments have created an additional opportunity to tackle one of the most debilitating burdens on global health and food security: parasitic nematodes. I review how development of nonparasitic nematodes as genetic models informs efforts to import tools into parasitic nematodes. Current tools in three commonly studied parasites (Strongyloides spp., Brugia malayi, and Ascaris suum) are described, as are tools from C. elegans that are ripe for adaptation and the benefits and barriers to doing so. These tools will enable dissection of a huge array of questions that have been all but completely impenetrable to date, allowing investigation into host-parasite and parasite-vector interactions, and the genetic basis of parasitism.

  12. Total, Soluble and Insoluble Oxalate Contents of Ripe Green and Golden Kiwifruit

    Directory of Open Access Journals (Sweden)

    Hà Vũ Hồng Nguyễn

    2013-03-01

    Full Text Available Three bulk samples of two different cultivars of kiwifruit, green (Actinidia deliciosa L. and golden (Actinidia chinensis L. were bought ripe, ready to eat from a local market. The aim of the study was to determine the oxalate composition of each of the three fractions of kiwifruit, namely skin, pulp and seeds. The pulp consisted of 90.4% of the edible portion of the two cultivars while the skin and seeds made up a mean of 8.0% and 1.6% respectively. Total oxalate was extracted with 2.0 M HCL at 21 °C for 15 min and soluble oxalates extracted at 21 °C in water for 15 min from each fraction. The total and soluble oxalate compositions of each fraction were determined using ion exchange HPLC chromatography. The pulp of golden kiwifruit contained lower amounts of total oxalates (15.7 vs. 19.3 mg/100 g FW and higher amounts of soluble oxalates (8.5 vs. 7.6 mg/100 g FW when compared to the green cultivar. The skin of the green cultivar contained lower levels of insoluble oxalates (36.9 vs. 43.6 mg/100 g FW, while the seeds of the green cultivar contained higher levels of insoluble oxalates 106.7 vs. 84.7 mg/100 g FW.

  13. Efeito da densidade e proporção de plantas de tomate industrial e de maria-pretinha em competição Density and proportion effects of industrial tomato and nightshade plants under competition

    Directory of Open Access Journals (Sweden)

    D.D. Hernandez

    2002-08-01

    Full Text Available O presente trabalho foi realizado com o objetivo de quantificar as interações competitivas e os índices de competitividade entre plantas de tomate industrial (Lycopersicon esculentum cv. Heinz 9553 e maria-pretinha (Solanum americanum. Usou-se como método um experimento substitutivo, com densidade total de 40 plantas m-2 e 11 proporções, além das monoculturas em densidades, que variaram de 20 a 100 plantas m-2, em intervalos de 20 plantas, conduzidos no delineamento de blocos casualizados com três repetições. Os resultados obtidos foram analisados pelo método convencional de análise de experimentos substitutivos e pela produção recíproca total. A maria-pretinha mostrou ser um competidor mais agressivo que o tomate, sendo mais importante a competição interespecífica para a planta cultivada. Para a biomassa seca total, as duas espécies não competiram pelos mesmos fatores de crescimento. Já para a área foliar, as duas espécies se mostraram competidoras pelos mesmos fatores de crescimento, mostrando ser essa a característica mais sensível à interferência.This work aimed to quantify the competitive interactions and the competitiveness indexes among plants of industrial tomato (Lycopersicon esculentum cv. Heinz 9553 and nightshade (Solanum americanum. The methodology used was a replacement series experiment with a total density of 40 plants m-2 and 11 proportions, besides the monocultures in densities varying from 20 to 100 plants m-2, in intervals of 20 plants, conducted in a randomized complete block design with three replications. The results were analyzed by the conventional method of analysis of replacement series experiment and for total reciprocal production. The nightshade plant was shown to be a more aggressive competitor than the tomato, with inter-specific competition being more important for the cultivated plant. For the dry aboveground biomasses, the two species did not compete for the same natural resources

  14. Effects of different pruning ways on the sugar-decreasing matters of pumpkin (Cucurbita moschata) fruits during the ripeness

    Institute of Scientific and Technical Information of China (English)

    NI Shujun; JIANG Xinmei; LIU Shouwei; YU Xihong

    2007-01-01

    This experiment used pumpkin Longyuanlixiang as material to research the effect of different pruning ways with one branch, two branches, and three branches on the sugar-decreasing matters during the ripeness of pumpkin (Cucurbita moschata) fruits. The results showed that pectin contents of pumpkin fruits during the ripeness all increased at first and then dropped in every treatment. The pectin contents under the treatments of one branch and two branches reached the high apex after pollinated for 30 d as well as for 35 d under the treatment of three branches. Pentose and chromium contents of fruits had the same trend under different pruning ways and increased during the ripenes. Three kinds of sugar-decreasing matters contents under treatment of two branches were bigger than treatment of one branch, while treatment of three branches was the lowest.

  15. 7 CFR 932.109 - Canned ripe olives of the tree-ripened type.

    Science.gov (United States)

    2010-01-01

    ... MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE...) Range in color from pinkish red, with some greenish cast, to black; and (2) Have not more than...

  16. Cooking enhances but the degree of ripeness does not affect provitamin A carotenoid bioavailability from bananas in Mongolian gerbils.

    Science.gov (United States)

    Bresnahan, Kara A; Arscott, Sara A; Khanna, Harjeet; Arinaitwe, Geofrey; Dale, James; Tushemereirwe, Wilberforce; Mondloch, Stephanie; Tanumihardjo, Jacob P; De Moura, Fabiana F; Tanumihardjo, Sherry A

    2012-12-01

    Banana is a staple crop in many regions where vitamin A deficiency is prevalent, making it a target for provitamin A biofortification. However, matrix effects may limit provitamin A bioavailability from bananas. The retinol bioefficacies of unripe and ripe bananas (study 1A), unripe high-provitamin A bananas (study 1B), and raw and cooked bananas (study 2) were determined in retinol-depleted Mongolian gerbils (n = 97/study) using positive and negative controls. After feeding a retinol-deficient diet for 6 and 4 wk in studies 1 and 2, respectively, customized diets containing 60, 30, or 15% banana were fed for 17 and 13 d, respectively. In study 1A, the hepatic retinol of the 60% ripe Cavendish group (0.52 ± 0.13 μmol retinol/liver) differed from baseline (0.65 ± 0.15 μmol retinol/liver) and was higher than the negative control group (0.39 ± 0.16 μmol retinol/liver; P bananas than in those fed raw (P = 0.0027). Body weights did not differ even though gerbils ate more green, ripe, and raw bananas than cooked, suggesting a greater indigestible component. In conclusion, thermal processing, but not ripening, improves the retinol bioefficacy of bananas. Food matrix modification affects carotenoid bioavailability from provitamin A biofortification targets.

  17. Composition of the essential oil of leaves, galls, and ripe and unripe fruits of Jordanian Pistacia palaestina Boiss.

    Science.gov (United States)

    Flamini, Guido; Bader, Ammar; Cioni, Pier Luigi; Katbeh-Bader, Ahmad; Morelli, Ivano

    2004-02-11

    Pistacia palaestina Boiss. (Pistacia terebinthus L. var. palaestina (Boiss.) Engl.) is a medicinal and foodstuff plant. The ripe fruits are used largely in the Middle East as a component of the so-called Zaatar, a mix of aromatic and food plants. Results of GC and GC-MS analyses of the essential oils of leaves, galls produced by Baizongia pistaciae (L.), and ripe and unripe fruits of Pistacia palaestinaBoiss. collected in Jordan are reported. Both qualitative and quantitative differences between different parts of the plant were observed. The oil was rich in monoterpenes, and the main constituents were alpha-pinene (63.1%) and myrcene (13.3%) in the leaves and alpha-pinene (49.4%), sabinene (22.8%), and limonene (8.1%) in the galls. (E)-Ocimene (33.8-41.3%), sabinene (20.3-24.1%), and (Z)-ocimene (3.8-13.0%) were the main ones in both unripe and ripe fruits. Sesquiterpenes have been detected in small quantities in leaves and fruits and in trace amounts in galls.

  18. Black Droplets

    CERN Document Server

    Santos, Jorge E

    2014-01-01

    Black droplets and black funnels are gravitational duals to states of a large N, strongly coupled CFT on a fixed black hole background. We numerically construct black droplets corresponding to a CFT on a Schwarzchild background with finite asymptotic temperature. We find two branches of such droplet solutions which meet at a turning point. Our results suggest that the equilibrium black droplet solution does not exist, which would imply that the Hartle-Hawking state in this system is dual to the black funnel constructed in \\cite{Santos:2012he}. We also compute the holographic stress energy tensor and match its asymptotic behaviour to perturbation theory.

  19. Black psyllium

    Science.gov (United States)

    Black psyllium is a weed that grows aggressively throughout the world. The plant was spread with the ... to make medicine. Be careful not to confuse black psyllium with other forms of psyllium including blond ...

  20. Global gene expression analysis of apple fruit development from the floral bud to ripe fruit

    Directory of Open Access Journals (Sweden)

    McArtney Steve

    2008-02-01

    Full Text Available Abstract Background Apple fruit develop over a period of 150 days from anthesis to fully ripe. An array representing approximately 13000 genes (15726 oligonucleotides of 45–55 bases designed from apple ESTs has been used to study gene expression over eight time points during fruit development. This analysis of gene expression lays the groundwork for a molecular understanding of fruit growth and development in apple. Results Using ANOVA analysis of the microarray data, 1955 genes showed significant changes in expression over this time course. Expression of genes is coordinated with four major patterns of expression observed: high in floral buds; high during cell division; high when starch levels and cell expansion rates peak; and high during ripening. Functional analysis associated cell cycle genes with early fruit development and three core cell cycle genes are significantly up-regulated in the early stages of fruit development. Starch metabolic genes were associated with changes in starch levels during fruit development. Comparison with microarrays of ethylene-treated apple fruit identified a group of ethylene induced genes also induced in normal fruit ripening. Comparison with fruit development microarrays in tomato has been used to identify 16 genes for which expression patterns are similar in apple and tomato and these genes may play fundamental roles in fruit development. The early phase of cell division and tissue specification that occurs in the first 35 days after pollination has been associated with up-regulation of a cluster of genes that includes core cell cycle genes. Conclusion Gene expression in apple fruit is coordinated with specific developmental stages. The array results are reproducible and comparisons with experiments in other species has been used to identify genes that may play a fundamental role in fruit development.

  1. Black Holes

    Science.gov (United States)

    Luminet, Jean-Pierre

    1992-09-01

    Foreword to the French edition; Foreword to the English edition; Acknowledgements; Part I. Gravitation and Light: 1. First fruits; 2. Relativity; 3. Curved space-time; Part II. Exquisite Corpses: 4. Chronicle of the twilight years; 5. Ashes and diamonds; 6. Supernovae; 7. Pulsars; 8. Gravitation triumphant; Part III. Light Assassinated: 9. The far horizon; 10. Illuminations; 11. A descent into the maelstrom; 12. Map games; 13. The black hole machine; 14. The quantum black hole; Part IV. Light Regained: 15. Primordial black holes; 16. The zoo of X-ray stars; 17. Giant black holes; 18. Gravitational light; 19. The black hole Universe; Appendices; Bibliography; Name index; Subject index.

  2. Elaboración de aceitunas denominadas “Green ripe olives” con variedades españolas

    Directory of Open Access Journals (Sweden)

    Brenes, Manuel

    2005-09-01

    Full Text Available Consumers are nowadays demanding a certain type of table olive with low acidity, a pH higher than 4.5 and yellow-green to yellow in colour. These are produced in the USA under the name “green ripe olivesâ€� and their sterilization is absolutely necessary. It was demonstrated in this work that the Spanish olive varieties Manzanilla and Hojiblanca can be elaborated as “green ripe olivesâ€� giving rise to a good quality product. However, it was also observed that after alkaline treatment the olives had to be thoroughly washed. A high volume of wash water was needed to neutralize olive flesh but also to eliminate certain compounds that gave rise to an undesirable odour in the final product as a consequence of the heat treatment. A rapid neutralization of olive flesh with CO2 was not enough to eliminate the off-odor. Likewise, the use of two alkaline treatments instead of only one did not improve the quality of the product. Therefore, it is considered necessary to study new alternative methods of preparing “green ripe olivesâ€� with less wash water volume and better organoleptic olive properties.Existe por parte de los consumidores una demanda creciente de aceitunas de muy baja acidez con pH superior a 4,5 y color verde amarillento/amarillo. Es necesario, por tanto, su esterilización y en Estados Unidos se conocen bajo la denominación “green ripe olivesâ€�. En este estudio se ha comprobado que las variedades españolas Manzanilla y Hojiblanca son susceptibles de elaborarse bajo la denominación “green ripe olivesâ€� aunque después del tratamiento alcalino es necesario llevar a cabo un número elevado de lavados de los frutos con vistas no sólo a neutralizar la pulpa sino también eliminar ciertos compuestos que originan un sabor inaceptable en el producto durante el tratamiento térmico. La neutralización rápida de la pulpa con anhídrido carbónico no es suficiente para reducir el n

  3. Life Cycle Assessment (LCA used to compare two different methods of ripe table olive processing

    Directory of Open Access Journals (Sweden)

    Russo, Carlo

    2010-06-01

    Full Text Available The aim of the present study is to analyze the most common method used for processing ripe table olives: the “California style”. Life Cycle Assessment (LCA was applied to detect the “hot spots” of the system under examination. The LCA results also allowed us to compare the traditional “California style”, here called “method A”, with another “California style”, here called “method B”. We were interested in this latter method, because the European Union is considering introducing it into the product specification of the Protected Denomination of Origin (PDO “La Bella della Daunia”. It was also possible to compare the environmental impacts of the two “California style” methods with those of the “Spanish style” method. From the comparison it is clear that “method B” has a greater environmental impact than “method A” because greater amounts of water and electricity are required, whereas “Spanish style” processing has a lower environmental impact than the ”California style” methods.

    El objetivo de este estudio es analizar el método más común utilizado para el procesamiento de la aceituna negra de mesa “estilo California” (Californian Style. La metodología LCA se aplicó para detectar los puntos calientes del sistema estudiado. Los resultados LCA también nos permitieron comparar el estilo californiano tradicional, aquí llamado “método A”, con otro estilo californiano, llamado “método B”. Nosotros estábamos interesados en el segundo método, porque la Unión Europea está considerando introducirlo en la Denominación de Origen Protegida (DOP “La Bella della Daunia”. También fue posible comparar los impactos medioambientales de los dos mètodos californianos con los impactos del método español. Observando la comparación, está claro que el “método B” tiene un mejor impacto ambiental que el “método A” porque este último requiere más cantidad de agua y

  4. 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.

  5. Effect of solvents and methods of stirring in extraction of lycopene, oleoresin and fatty acids from over-ripe tomato.

    Science.gov (United States)

    López-Cervantes, Jaime; Sánchez-Machado, Dalia I; Valenzuela-Sánchez, Karla P; Núñez-Gastélum, José A; Escárcega-Galaz, Ana A; Rodríguez-Ramírez, Roberto

    2014-03-01

    Lycopene and oleoresin extraction from powder of tomato over-ripe by three agitation methods and four solvents have been evaluated. Also, tomato powder and the oleoresins were characterized biochemically. On average, the moisture content of powder was found to be 4.30, ash 8.90, proteins 11.23 and lipids 4.35 g 100 g(-1). The best oleoresin extraction yield was achieved by combining sonication and acetone at 1.43 g 100 g(-1). The greatest amount of lycopene (65.57 ± 0.33 mg 100 g(-1)) was also obtained using the same treatment. The presence of trans-lycopene was positively confirmed by HPLC and FTIR. In oleoresins, linoleic acid (C18:2n6) was the predominant with 50% of total fatty acids, whereas stearic acid (C18:0) is presented in a smaller proportion (5%). A simple and suitable method for extraction of lycopene from over-ripe tomato was optimized. In industrial applications, tomato by-products are a viable source of analytes, such as lycopene and unsaturated fatty acids.

  6. Dry and ripe fruit of Aegle marmelos. L: A potent source of antioxidant, lipoxygenase inhibitors and free radical scavenger.

    Science.gov (United States)

    Rahman, Atiqur; Imran, Hina; Iqbal, Lubna; STaqvi, Syed Intasar Hussain; Fatima, Nudrat; Yaqeen, Zahra

    2016-07-01

    The antioxidant, lipoxygenase inhibitory activities and free radical scavenging capacity of the crude extract, aqueous and some organic fractions of dry and ripe fruit of Aeglemarmelos. L were studied to understand the protective and therapeutic role for the use of the fruit as a remedy in different ailments. All the tested fractions and extracts showed to possess significant antioxidant, free radical scavenging capacity and lipoxygenase inhibitory potential. However, chloroform and aqueous fractions showed significant ability to quench radicals, to reduce ferric chloride and to inhibit soyabean lipoxygenase. Their antioxidant and lipoxygenase inhibition was estimated by IC50 values, for antioxidant ranging from 88-65% activity at concentration of 5-0.15μ/mL and similarly for lipoxygenase inhibition ranging from 89-69% at various concentrations of 5-0.15μ/mL, in chloroform and aqueous fractions respectively. The scavenger molecules in the dry and ripe fruit of A. marmelos may attribute to therapeutic and protective effect during different progressive stages of ailments.

  7. Lipolytic activity of the yeast species associated with the fermentation/storage phase of ripe olive processing.

    Science.gov (United States)

    Rodríguez-Gómez, F; Arroyo-López, F N; López-López, A; Bautista-Gallego, J; Garrido-Fernández, A

    2010-08-01

    Ripe olives account for ca. 30% of the world's table olive production. Fruits intended for this type of product are preserved in an aqueous solution (acidic water or brine) for several months, where they may undergo a spontaneous fermentation. Enterobacteriaceae and lactic acid bacteria were not detected in the present survey during storage. Thus, the work focused on studying the yeast microflora associated with the ripe olive storage of Manzanilla and Hojiblanca cultivars in acidified brines. A total of 90 yeast isolates were identified by means of molecular methods using RFLP analysis of the 5.8S-ITS rDNA region and sequencing of the D1/D2 domains of the 26S rDNA gene. The two most important species identified in both cultivars were Saccharomyces cerevisiae and Pichia galeiformis, which were present throughout the storage period, while Candida boidinii was detected during the later stages of the process. The species Pichia membranifaciens was detected only in the early stages of the Hojiblanca cultivar. The lipase assays performed with both extracellular and whole cell fractions of the yeast isolates showed that neither of the S. cerevisiae and P. galeiformis species had lipase activity, while the P. membranifaciens isolates showed a weak activity. On the contrary, all C. boidinii isolates gave a strong lipase activity. Change in olive fat acidity was markedly higher in the presence of the yeast population than in sterile storage, indicating that lipases produced by these microorganisms modify the characteristics of the fat in the fruit.

  8. Black tea

    Science.gov (United States)

    ... combination.Talk with your health provider.Birth control pills (Contraceptive drugs)Black tea contains caffeine. The body breaks down caffeine to get rid of it. Birth control pills can decrease how quickly the body breaks down ...

  9. Evaluation of the nutraceutical, antioxidant and cytoprotective properties of ripe pistachio (Pistacia vera L., variety Bronte) hulls.

    Science.gov (United States)

    Barreca, Davide; Laganà, Giuseppina; Leuzzi, Ugo; Smeriglio, Antonella; Trombetta, Domenico; Bellocco, Ersilia

    2016-04-01

    Every year tons of pistachio hulls are separated and eliminated, as waste products, from pistachio seeds. In this study the hulls of ripe pistachios were extracted with two organic solvents (ethanol and methanol) and characterized for phenolic composition, antioxidant power and cytoprotective activity. RP-HPLC-DAD-FLU separation enabled us to identify 20 derivatives, including and by far the most abundant gallic acid, 4-hydroxybenzoic acid, protocatechuic acid, naringin, eriodictyol-7-O-glucoside, isorhamnetin-7-O-glucoside, quercetin-3-O-rutinoside, isorhamnetin-3-O-glucoside and catechin. Methanol extraction gave the highest yields for all classes of compounds and presented a higher scavenging activity in all the antioxidant assays performed. The same was found for cytoprotective activity on lymphocytes, lipid peroxidation and protein degradation. These findings highlight the strong antioxidant and cytoprotective activity of the extract components, and illustrate how a waste product can be used as a source of nutraceuticals to employ in manufacturing industry.

  10. In vitro trypanocidal evaluation of pinane derivatives from essential oils of ripe fruits from Schinus terebinthifolius Raddi (Anacardiaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Sartorelli, Patricia; Santana, Jefferson S.; Guadagnin, Rafael C.; Lago, Joao Henrique G., E-mail: joao.lago@unifesp.br [Instituto de Ciencias Ambientais, Quimicas e Farmaceuticas, Universidade Federal de Sao Paulo, Diadema - SP (Brazil); Pinto, Erika G. [Departamento de Parasitologia, Instituto Adolfo Lutz, Sao Paulo - SP (Brazil); Instituto de Medicina Tropical de Sao Paulo, Universidade de Sao Paulo, SP (Brazil); Tempone, Andre G. [Departamento de Parasitologia, Instituto Adolfo Lutz, Sao Paulo - SP (Brazil); Stefani, Helio A. [Departamento de Farmacia, Faculdade de Ciencias Farmaceuticas, Universidade de Sao Paulo, SP (Brazil); Soares, Marisi G. [Instituto de Quimica, Universidade Federal de Alfenas, Alfenas - MG (Brazil); Silva, Adalberto M. da [Departamento de Quimica, Universidade Federal de Vicosa, MG (Brazil)

    2012-07-01

    Essential oils of ripe fruits from Schinus terebinthifolius (Anacardiaceae), obtained using a pilot extractor and a Clevenger apparatus were chemically characterized. Due the high amount of (-)-{alpha}-pinene in both oils, this monoterpene was tested against the protozoan parasite Trypanosoma cruzi, showing a moderate potential (IC{sub 50} 63.56 {mu}g/mL) when compared to benznidazole (IC{sub 50} 43.14 {mu}g/mL). Otherwise, (-)-{alpha}-pinene oxide did not showed anti-trypanosomal activity (IC{sub 50} > 400 {mu}g/mL) while (-)-pinane showed an IC{sub 50} of 56.50 mg/mL. The obtained results indicated that the epoxidation of {alpha}-pinene results to the loss of the anti-parasitic activity while its hydrogenation product, contributed slightly to the increased activity. (author)

  11. Inoculation of the nonlegume Capsicum annuum (L.) with Rhizobium strains. 1. Effect on bioactive compounds, antioxidant activity, and fruit ripeness.

    Science.gov (United States)

    Silva, Luís R; Azevedo, Jessica; Pereira, Maria J; Carro, Lorena; Velazquez, Encarna; Peix, Alvaro; Valentão, Patrícia; Andrade, Paula B

    2014-01-22

    Pepper (Capsicum annuum L.) is an economically important agricultural crop and an excellent dietary source of natural colors and antioxidant compounds. The levels of these compounds can vary according to agricultural practices, like inoculation with plant growth-promoting rhizobacteria. In this work we evaluated for the first time the effect of the inoculation of two Rhizobium strains on C. annuum metabolites and bioactivity. The results revealed a decrease of organic acids and no effect on phenolics and capsaicinoids of leaves from inoculated plants. In the fruits from inoculated plants organic acids and phenolic compounds decreased, showing that fruits from inoculated plants present a higher ripeness stage than those from uninoculated ones. In general, the inoculation with Rhizobium did not improve the antioxidant activity of pepper fruits and leaves. Considering the positive effect on fruit ripening, the inoculation of C. annuum with Rhizobium is a beneficious agricultural practice for this nonlegume.

  12. Yield and quality of pectins extractable from the peels of thai mango cultivars depending on fruit ripeness.

    Science.gov (United States)

    Sirisakulwat, Suparat; Nagel, Andreas; Sruamsiri, Pittaya; Carle, Reinhold; Neidhart, Sybille

    2008-11-26

    Pectins, recovered from the peels of four mango ( Mangifera indica L.) cultivars by mimicking industrial techniques, were evaluated in terms of yield, composition, macromolecular properties, and technofunctional quality. Freeze-dried peels of mature-green fruits, after major mesocarp softening, and at full ripeness were extracted using hot acid. The pectins were precipitated in propan-2-ol and their crude yields quantified as alcohol-insoluble substance. Like apple pomace, the dried peels provided hardly acetylated (DAc mango peel pectins less valuable than commercial apple pectins with regard to gelling capacity and thickening properties. Whereas starch and matrix glycan fragments almost completely degraded during ripening, depolymerization of pectins and galactans was insignificant. Technofunctional properties, modulated by extraction at different pH values, were ascribed to structural differences influencing macromolecular entanglements.

  13. The O-methyltransferase gene MdoOMT1 is required for biosynthesis of methylated phenylpropenes in ripe apple fruit.

    Science.gov (United States)

    Yauk, Yar-Khing; Chagné, David; Tomes, Sumathi; Matich, Adam J; Wang, Mindy Y; Chen, Xiuyin; Maddumage, Ratnasiri; Hunt, Martin B; Rowan, Daryl D; Atkinson, Ross G

    2015-06-01

    Phenylpropenes, such as eugenol and trans-anethole, are important aromatic compounds that determine flavour and aroma in many herbs and spices. Some apple varieties produce fruit with a highly desirable spicy/aromatic flavour that has been attributed to the production of estragole, a methylated phenylpropene. To elucidate the molecular basis for estragole production and its contribution to ripe apple flavour and aroma we characterised a segregating population from a Royal Gala (RG, estragole producer) × Granny Smith (GS, non-producer) apple cross. Two quantitative trait loci (QTLs; accounting for 9.2 and 24.8% of the variation) on linkage group (LG) 1 and LG2 were identified that co-located with seven candidate genes for phenylpropene O-methyltransferases (MdoOMT1-7). Of these genes, only expression of MdoOMT1 on LG1 increased strongly with ethylene and could be correlated with increasing estragole production in ripening RG fruit. Transient over-expression in tobacco showed that MdoOMT1 utilised a range of phenylpropene substrates and catalysed the conversion of chavicol to estragole. Royal Gala carried two alleles (MdoOMT1a, MdoOMT1b) whilst GS appeared to be homozygous for MdoOMT1b. MdoOMT1a showed a higher affinity and catalytic efficiency towards chavicol than MdoOMT1b, which could account for the phenotypic variation at the LG1 QTL. Multiple transgenic RG lines with reduced MdoOMT1 expression produced lower levels of methylated phenylpropenes, including estragole and methyleugenol. Differences in fruit aroma could be perceived in these fruit, compared with controls, by sensory analysis. Together these results indicate that MdoOMT1 is required for the production of methylated phenylpropenes in apple and that phenylpropenes including estragole may contribute to ripe apple fruit aroma.

  14. Accumulation of soluble sugars in peel at high temperature leads to stay-green ripe banana fruit.

    Science.gov (United States)

    Yang, Xiaotang; Pang, Xuequn; Xu, Lanying; Fang, Ruiqiu; Huang, Xuemei; Guan, Peijian; Lu, Wangjin; Zhang, Zhaoqi

    2009-01-01

    Bananas (Musa acuminata, AAA group) fail to develop a yellow peel and stay green when ripening at temperatures >24 degrees C. The identification of the mechanisms leading to the development of stay-green ripe bananas has practical value and is helpful in revealing pathways involved in the regulation of chlorophyll (Chl) degradation. In the present study, the Chl degradation pathway was characterized and the progress of ripening and senescence was assessed in banana peel at 30 degrees C versus 20 degrees C, by monitoring relevant gene expression and ripening and senescence parameters. A marked reduction in the expression levels of the genes for Chl b reductase, SGR (Stay-green protein), and pheophorbide a oxygenase was detected for the fruit ripening at 30 degrees C, when compared with fruit at 20 degrees C, indicating that Chl degradation was repressed at 30 degrees C at various steps along the Chl catabolic pathway. The repressed Chl degradation was not due to delayed ripening and senescence, since the fruit at 30 degrees C displayed faster onset of various ripening and senescence symptoms, suggesting that the stay-green ripe bananas are of similar phenotype to type C stay-green mutants. Faster accumulation of high levels of fructose and glucose in the peel at 30 degrees C prompted investigation of the roles of soluble sugars in Chl degradation. In vitro incubation of detached pieces of banana peel showed that the pieces of peel stayed green when incubated with 150 mM glucose or fructose, but turned completely yellow in the absence of sugars or with 150 mM mannitol, at either 20 degrees C or 30 degrees C. The results suggest that accumulation of sugars in the peel induced by a temperature of 30 degrees C may be a major factor regulating Chl degradation independently of fruit senescence.

  15. Differences in the volatile components and their odor characteristics of green and ripe fruits and dried pericarp of Japanese pepper (Xanthoxylum piperitum DC.).

    Science.gov (United States)

    Jiang, Lihua; Kubota, Kikue

    2004-06-30

    The essential oils of green and ripe fruits and dried pericarp of Japanese pepper (Xanthoxylum piperitum DC.), which are commonly used in Japanese dishes as spices, were extracted with methanol, followed by adsorption to Porapak Q resin. Their aroma profiles were characterized by a sensory evaluation, and their chemical constituents were investigated by using gas chromatography (GC), gas chromatography-mass spectrometry, and aroma extract dilution analysis. Geraniol, citronellal, linalool, and methyl cinnamate were perceived to be important to the basic flavor of the three samples of Japanese pepper by GC-sniffing at high flavor dilution (FD) factors. Monoterpene hydrocarbons constituting almost 76% of the essential oil are the major flavor compounds in the green fruit, and the stronger green and pine leaf notes in the green fruit were considered to be imparted mainly by the large amount of d-limonene, beta-phellandrene, and myrcene due to their high FD factors. On the other hand, the oxygenated terpenes including citronellal, geraniol, and geranial are predominant for the potent odorant in the ripe fruit. The marked citrus-like note in the ripe fruit was thought to be due to the amounts of geranial and citronellal, being 20% of the essential oil. In the dried pericarp, the ratio of oxygenated terpenoids was almost equal to that of monoterpene hydrocarbons. These seemed to induce the flavor character of the dried pericarp to be milder than that of the ripe fruit.

  16. Manual Arts to Technology Education: Are We Ripe for Infusing Aspects of a Green Technology into Career and Technical Education Constituent Subjects?

    Science.gov (United States)

    Asunda, Paul A.

    2010-01-01

    This paper is a conceptual essay that reviews industrial and economic changes that have shaped vocational education to present day Career and Technical Education (CTE) curriculum, and specifically the role of technology education in meeting societal needs. An argument is presented that CTE is ripe to integrate aspects of green technology and…

  17. Black holes

    CERN Document Server

    Chrúsciel, P T

    2002-01-01

    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 usual one for gravity, and leads to the one associated with the Unruh metric in the case of Euler equations. We review the global conditions which have been used in the Scri-based definition of a black hole and point out the deficiencies of the Scri approach. Various results on the structure of horizons and apparent horizons are presented, and a new proof of semi-convexity of horizons based on a variational principle is given. Recent results on the classification of stationary singularity-free vacuum solutions are reviewed. ...

  18. Chemical composition, at consuming ripeness level of tomatoes irradiated at mature green and greenish yellow stages of maturity

    Science.gov (United States)

    Al-Wandawi, H. K.; Abdul-Rahman, M. H.; Al-Shaickley, K. A.

    Tomatoes (Lycopersicon esculentum L.,var.Monte carlo) have been Y-irradiated (100-400Krad) and left to ripen to consuming ripeness. The results revealed that in fruits irradiated with 100,200 and 300 krad at mature-green, 48 hour after harvesting and at greenish yellow stages of maturity, 24 hours after harvesting, the levels of ascorbic acid were accounted to 62, 51, 27% and 84, 59, 34% of control samples respectively. In fruits irradiated with 200 krad at mature-green stage and 48 hours after harvesting and in fruits irradiated with 400 krad at greenish yellow stage and 48 hours after harvesting, the levels of lycopene were 279 and 246% of that of control samples; while the lowest levels of lycopene were in fruits irradiated with 400 krad and at mature-green and greenish yellow stages and 48 hours after harvesting where lycopene accounted to 11 and 24% respectively when compared to control samples . on the other hand, radiation had no significant effect on PH, titrable acidity and °Brix of tomatoes.

  19. Anxiolytic-like effect of hydroalcoholic extract of ripe pistachio hulls in adult female Wistar rats and its possible mechanisms

    Science.gov (United States)

    Rostampour, Mohammad; Hadipour, Elham; Oryan, Shahrbano; Soltani, Bahram; Saadat, Farshid

    2016-01-01

    The present study was designed to study the preventive effect of hydroalcoholic extract of ripe pistachio hulls (RPH) in the elevated plus maze model of anxiety. One hundred twenty female wistar rats in their estrous cycle were divided into 15 groups of 8 each and received various concentrations of hydroalcoholic extract of RPH except the control groups. Elevated plus maze was used to measure the level of anxiety. Percentage of time spent in the open arms (%OAT), percentage of the number of entries into the open arms (%OAE), locomotor activity, and time spent in the closed arms (CAT), and the number of entries in to the closed arms (CAE) were measured and compared. Dose-response experiments showed that only 10 mg/kg dose of RPH extract significantly increased %OAT (P < 0.001) and %OAE (P < 0.05) compared to the control group, indicating anti-anxiety effects of the extract. Also, pentylenetetrazol and an estrogen receptor antagonist (ERA) tamoxifen could block anti-anxiety effects of the extract (P < 0.001). It was also noticed that tamoxifen was able to significantly reduce locomotor activity. As the RPH extract showed a preventive effect in experimental model of anxiety, it might be concomitantly administered with other anxiolytic medications. PMID:28003838

  20. iTRAQ protein profile analysis of tomato green-ripe mutant reveals new aspects critical for fruit ripening.

    Science.gov (United States)

    Pan, Xiaoqi; Zhu, Benzhong; Zhu, Hongliang; Chen, Yuexi; Tian, Huiqin; Luo, Yunbo; Fu, Daqi

    2014-04-01

    Green-ripe (Gr) tomato carries a dominant mutation and yields a nonripening fruit phenotype. The mutation results from a 334 bp deletion in a gene of unknown function at the Gr locus. The putative influence of Gr gene-deletion mutation on biochemical changes underlying the nonripening phenotype remains largely unknown. Respiration of Gr fruit was found to be reduced at mature green and breaker stage of ripening, while the fruit softening was dramatically prolonged. We studied the proteome of Gr mutant fruit using high-throughput iTRAQ and high-resolution mass spectrometry and identified 43 proteins representing 43 individual genes as potential influence-targets of Gr mutated fruit. The identified proteins are involved in several ripening-related pathways including cell-wall metabolism, photosynthesis, oxidative phosphorylation, carbohydrate and fatty acid metabolism, protein synthesis, and processing. Affected protein levels are correlated with the corresponding gene transcript levels. The modulation in the accumulation levels of PI(U1)P, PGIP, and PG2 supported the delayed softening phenotype of the Gr fruit. Further investigation in GR gene-silencing fruit ascertained the doubtless modulation of these targets by the deletion mutation of GR gene.

  1. Chemical composition, at consuming ripeness level of tomatoes irradiated at mature green and greenish yellow stages of maturity. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Wandawi, H.K.; Abdul-Rahman, M.H.; Al-Shaickley, K.A. (Iraq Atomic Energy Commission, Baghdad. Nuclear Research Inst.)

    1983-01-01

    Tomatoes (Lycopersicon esculentum L., var. Monte Carlo) have been ..gamma..-irradiated (100 to 400 krad) and left to ripen to consuming ripeness. The results revealed that in fruits irradiated with 100, 200 and 300 krad at mature-green, 48 hours after harvesting and at greenish yellow stages of maturity, 24 hours after harvesting, the levels of ascorbic acid were accounted to 62, 51, 27% and 84, 59, 34% of control samples respectively. In fruits irradiated with 200 krad at mature-green stage and 48 hours after harvesting and in fruits irradiated with 400 krad at greenish yellow stage and 48 hours after harvesting, the levels of lycopene were 279 and 246% of that of control samples; while the lowest levels of lycopene were in fruits irradiated with 400 krad and at mature-green and greenish yellow stages and 48 hours after harvesting where lycopene accounted to 11 and 24% respectively when compared to control samples. On the other hand, radiation had no significant effect on PH, titrable acidity and deg Brix of tomatoes.

  2. Comparative transcriptome analysis of unripe and mid-ripe fruit of Mangifera indica (var. "Dashehari") unravels ripening associated genes.

    Science.gov (United States)

    Srivastava, Smriti; Singh, Rajesh K; Pathak, Garima; Goel, Ridhi; Asif, Mehar Hasan; Sane, Aniruddha P; Sane, Vidhu A

    2016-09-02

    Ripening in mango is under a complex control of ethylene. In an effort to understand the complex spatio-temporal control of ripening we have made use of a popular N. Indian variety "Dashehari" This variety ripens from the stone inside towards the peel outside and forms jelly in the pulp in ripe fruits. Through a combination of 454 and Illumina sequencing, a transcriptomic analysis of gene expression from unripe and midripe stages have been performed in triplicates. Overall 74,312 unique transcripts with ≥1 FPKM were obtained. The transcripts related to 127 pathways were identified in "Dashehari" mango transcriptome by the KEGG analysis. These pathways ranged from detoxification, ethylene biosynthesis, carbon metabolism and aromatic amino acid degradation. The transcriptome study reveals differences not only in expression of softening associated genes but also those that govern ethylene biosynthesis and other nutritional characteristics. This study could help to develop ripening related markers for selective breeding to reduce the problems of excess jelly formation during softening in the "Dashehari" variety.

  3. Antioxidant and Antiplatelet Activities in Extracts from Green and Fully Ripe Tomato Fruits (Solanum lycopersicum) and Pomace from Industrial Tomato Processing

    OpenAIRE

    Eduardo Fuentes; Reinhold Carle; Luis Astudillo; Luis Guzmán; Margarita Gutiérrez; Gilda Carrasco; Iván Palomo

    2013-01-01

    The consumption of fruits and vegetables is accepted to be one of the strategies to reduce risk factors for these diseases. The aim of this study was to examine potential relationships between the antioxidant and the antiplatelet activities in green mature and fully ripe (red) tomatoes and of lycopene-rich byproducts of tomato paste processing such as pomace. The total phenol content of tomato components was the highest in peels, pulp, and in the mucilaginous myxotesta covering the tomato see...

  4. Improved Maturity and Ripeness Classifications of Magnifera Indica cv. Harumanis Mangoes through Sensor Fusion of an Electronic Nose and Acoustic Sensor

    Directory of Open Access Journals (Sweden)

    Latifah Munirah Kamarudin

    2012-05-01

    Full Text Available In recent years, there have been a number of reported studies on the use of non-destructive techniques to evaluate and determine mango maturity and ripeness levels. However, most of these reported works were conducted using single-modality sensing systems, either using an electronic nose, acoustics or other non-destructive measurements. This paper presents the work on the classification of mangoes (Magnifera Indica cv. Harumanis maturity and ripeness levels using fusion of the data of an electronic nose and an acoustic sensor. Three groups of samples each from two different harvesting times (week 7 and week 8 were evaluated by the e-nose and then followed by the acoustic sensor. Principal Component Analysis (PCA and Linear Discriminant Analysis (LDA were able to discriminate the mango harvested at week 7 and week 8 based solely on the aroma and volatile gases released from the mangoes. However, when six different groups of different maturity and ripeness levels were combined in one classification analysis, both PCA and LDA were unable to discriminate the age difference of the Harumanis mangoes. Instead of six different groups, only four were observed using the LDA, while PCA showed only two distinct groups. By applying a low level data fusion technique on the e-nose and acoustic data, the classification for maturity and ripeness levels using LDA was improved. However, no significant improvement was observed using PCA with data fusion technique. Further work using a hybrid LDA-Competitive Learning Neural Network was performed to validate the fusion technique and classify the samples. It was found that the LDA-CLNN was also improved significantly when data fusion was applied.

  5. black cat

    Institute of Scientific and Technical Information of China (English)

    杜铁梅

    2016-01-01

    The black cat is a masterpiece of short fiction of Poe. He successfully solved the problem of creating of the horror effect by using scene description, symbol, repetition and first-person narrative methods. And created a complete and unified mysterious terror, achieved the effect of shocking. This paper aims to discuss the mystery in-depth and to enrich the research system in Poe’s novels.

  6. Describing Quality and Sensory Attributes of 3 Mango (Mangifera indica L.) Cultivars at 3 Ripeness Stages Based on Firmness.

    Science.gov (United States)

    Nassur, Rita de Cássia Mirela Resende; González-Moscoso, Sara; Crisosto, Gayle M; Lima, Luiz Carlos de Oliveira; Vilas Boas, Eduardo Valério de Barros; Crisosto, Carlos H

    2015-09-01

    To determine the ideal ripening stage for consumption of the mango cultivars, "Ataulfo," "Haden," and "Tommy Atkins"; fruits at 3 flesh firmness levels (ripeness stages) were evaluated by a trained panel using descriptive analysis after instrumental measurements were made. After harvest, all fruits were ripened to allow softening and quality and sensory attribute changes. Ripening changes during softening of Ataulfo mangos were expressed by a characteristic increase in the perception of "tropical fruit" and "peach" aromas, an increase in "juiciness," "sweetness," and "tropical fruit" flavor, while "fibrousness," "chewiness," and "sourness" decreased. Similar desirable sensory changes were also detected during softening of Haden mangos; an increase in tropical fruit and peach aromas, sweetness and tropical fruit flavor, and a decrease in chewiness, sourness, and bitterness. Softening of Tommy Atkins mangos was followed by reduced chewiness and sourness and increased peach aroma. Softening of all cultivars was followed by decreased sourness and titratable acidity (TA) and increased soluble solids concentration (SSC) and SSC:TA ratio. The results indicate that mango ripening leads to increased expression of sensory attributes such as tropical fruit and peach aromas, tropical flavor, and sweetness that have been related to improved eating quality and these final changes in sensory quality attributes are specific for each cultivar. For example, Ataulfo and Haden mangos had greater improvement in quality and sensory attributes related to fruit eating quality during ripening-softening than Tommy Atkins. In our consumer test, these quality-sensory attributes expressed during ripening that were perceived by the trained panel were also validated, supporting the need for a controlled ripening protocol in mangos.

  7. Specific responses of Salmonella enterica to tomato varieties and fruit ripeness identified by in vivo expression technology.

    Directory of Open Access Journals (Sweden)

    Jason T Noel

    Full Text Available BACKGROUND: Recent outbreaks of vegetable-associated gastroenteritis suggest that enteric pathogens colonize, multiply and persist in plants for extended periods of time, eventually infecting people. Genetic and physiological pathways, by which enterics colonize plants, are still poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: To better understand interactions between Salmonella enterica sv. Typhimurium and tomatoes, a gfp-tagged Salmonella promoter library was screened inside red ripe fruits. Fifty-one unique constructs that were potentially differentially regulated in tomato relative to in vitro growth were identified. The expression of a subset of these promoters was tested in planta using recombinase-based in vivo expression technology (RIVET and fitness of the corresponding mutants was tested. Gene expression in Salmonella was affected by fruit maturity and tomato cultivar. A putative fadH promoter was upregulated most strongly in immature tomatoes. Expression of the fadH construct depended on the presence of linoleic acid, which is consistent with the reduced accumulation of this compound in mature tomato fruits. The cysB construct was activated in the fruit of cv. Hawaii 7997 (resistant to a race of Ralstonia solanacearum more strongly than in the universally susceptible tomato cv. Bonny Best. Known Salmonella motility and animal virulence genes (hilA, flhDC, fliF and those encoded on the pSLT virulence plasmid did not contribute significantly to fitness of the bacteria inside tomatoes, even though deletions of sirA and motA modestly increased fitness of Salmonella inside tomatoes. CONCLUSIONS/SIGNIFICANCE: This study reveals the genetic basis of the interactions of Salmonella with plant hosts. Salmonella relies on a distinct set of metabolic and regulatory genes, which are differentially regulated in planta in response to host genotype and fruit maturity. This enteric pathogen colonizes tissues of tomatoes differently than plant

  8. Black gold

    CERN Document Server

    Fletcher, MW

    2016-01-01

    Following the Yom Kippur war of October 1973, OPEC raises the price of oil by 70% along with a 5% reduction in oil production. Len Saunders a highly skilled and knowledgeable British engineer for Jaguar motors, is approached by the UK energy commission in the January of 1974 to create a new propulsion system; using a secret document from a German WW2 scientist, that they have come into possession of. Len Saunders sets to work on creating the holy grail of energy. Seven years later 1981, Haidar Farooq the Kuwait oil minister working at OPEC and head of a secret organisation named Black Gold bec

  9. A Ripe Old Age

    Institute of Scientific and Technical Information of China (English)

    TANG YUANKAI

    2010-01-01

    @@ Born in 1885,Luo Meizhen can still move quickly and can see and hear well.Until this year,she had climbed a nearby mountain nearly every day to carry out farm work.The lady was recently named the oldest person in China.

  10. Time ripe for superconductivity?

    Directory of Open Access Journals (Sweden)

    George Marsh

    2002-04-01

    But there is a crucial deadline and failure to meet it could send superconductivity back to the commercial shadows (at least outside the medical and scientific niches where it is a key enabler in analytical instruments, magnetic resonance imaging, and particle accelerators for another 30 years. Later this decade, the vintage infrastructure of dense copper conductors that supports power distribution in developed countries, in particular in the US, will become due for renewal. (Recent power problems in California were largely those of distribution infrastructure. At the same time, boosting capacity to serve the needs of increasingly affluent populations will pose a challenge. Superconductivity could provide the answer — if the technology matures in time and cost targets are met.

  11. Black Urine

    Directory of Open Access Journals (Sweden)

    Rahim Vakili

    2016-06-01

    Full Text Available A 2-year-old boy was born at term of healthy, non-consanguineous Iranian parents. His mother attended in the clinic with the history of sometimes discoloration of diapers after passing urine. She noticed that first at the age of one month with intensified in recent months. His Physical examination and growth parameters were normal. His mother denied taking any medication (sorbitol, nitrofurantoin, metronidazole, methocarbamol, sena and methyldopa (5. Qualitative urine examination showed dark black discoloration. By this history, alkaptonuria was the most clinical suspicious. A 24-hour-urine sample was collected and sent for quantitative measurements. The urine sample was highly positive for homogentisic acid and negative for porphyrin metabolites.

  12. Análise de crescimento e partição de assimilados em plantas de maria-pretinha submetidas a níveis de sombreamento Growth analysis and partitioning of assimilates in mary-nightshade plants submitted to shading levels

    Directory of Open Access Journals (Sweden)

    T.Z Aumonde

    2013-03-01

    Full Text Available A espécie Solanum americanum (maria-pretinha é considerada planta daninha; por possuir elevada habilidade competitiva e agressividade, ela reduz a produtividade dos cultivos. O trabalho foi conduzido em casa de vegetação e objetivou analisar o crescimento e a partição de assimilados em plantas de maria-pretinha submetidas a três níveis de sombreamento. As plantas foram coletadas em intervalos regulares de sete dias após o transplante até o final do ciclo, sendo determinada a massa seca e a área foliar. A partir dos dados primários, foi aplicada a análise de crescimento, sendo calculados a massa seca total (Wt, as taxas de produção de matéria seca (Ct, crescimento relativo (Rw e assimilatória líquída (Ea, o índice de área foliar (L, as razões de área foliar (Fa e massa foliar (Fw, a área foliar específica (Sa, a partição de matéria seca entre órgãos e o número de frutos. Plantas de maria-pretinha cresceram e se desenvolveram melhor sob condição intermediária de luz (65%, em que atingiram maior Wt, Ct, L, Fa, matéria seca de caule, matéria seca de fruto e maior número de frutos, enquanto a luz plena e a redução da luminosidade em nível acentuado, de maneira mais marcante, afetaram negativamente o crescimento e o desenvolvimento, o que possivelmente pode influenciar a habilidade competitiva da maria-pretinha.The species Solanum americanum (mary-nightshade is considered a weed whose highly competitive ability and aggressiveness reduce crop productivity. This work was conducted under greenhouse conditions aiming to analyze the growth and partitioning of assimilates in mary-nightshade plants subjected to three levels of shading. The plants were collected at regular intervals of seven days after transplantation until the end of the cycle, with dry mass and leaf area being determined. Based on primary data , growth analysis was carried out to calculate total dry matter production (Wt, dry matter production rates

  13. Role of aqueous extract of morinda citrifolia (Indian noni ripe fruits in inhibiting dental caries-causing streptococcus mutans and streptococcus mitis.

    Directory of Open Access Journals (Sweden)

    Barani Kumarasamy

    2014-12-01

    Full Text Available Use of alternative medicine to control oral streptococci is a new topic worthy of further investigation. This study aimed to elucidate the dose-dependent anti-bacterial activity of crude aqueous extract of ripe Morinda citrifolia L. (Family: Rubiaceae fruits against oral streptococci i.e. Streptococcus mutans and Streptococcus mitis, that cause dental caries in humans.Fresh ripe M. citrifolia fruits (750g were ground in an electronic blender with sterile water (500ml. The crude aqueous extract was lyophilized to yield a brown colored powder. Various concentrations (1000-100μg/ ml of the extract were tested for its antibacterial activity (Kirby and Bauer method against whole cells of S. mutans and S. mitis. Minimum Inhibitory Concentration (MIC was determined by micro-dilution method, using serially diluted (2 folds fruit extract, according to the National Committee for Clinical Laboratory Standards (NCCLS.Crude aqueous extract (1000μg/ ml of ripe M. citrifolia fruits effectively inhibited the growth of S. mutans (19±0.5 mm and S. mitis (18.6±0.3 mm compared to the streptomycin control (21.6±0.3 mm. The growth inhibition was clearly evident with "nil" bacteriostasis, even after 48 hours of incubation at 37°C. The MIC of the extract for S. mutans and S. mitis was 125 μg and 62.5 μg, respectively.Our results suggest that phytochemicals naturally synthesized by M. citrifolia have an inhibitory effect on oral streptococci. Furthermore, purification and molecular characterization of the "bioactive principle" would enable us to formulate a sustainable oral hygiene product.

  14. Dissonant Black Droplets and Black Funnels

    CERN Document Server

    Fischetti, Sebastian; Way, Benson

    2016-01-01

    A holographic field theory on a fixed black hole background has a gravitational dual represented by a black funnel or a black droplet. These states are "detuned" when the temperature of the field theory near the horizon does not match the temperature of the background black hole. In particular, the gravitational dual to the Boulware state must be a detuned solution. We construct detuned droplets and funnels dual to a Schwarzschild background and show that the Boulware phase is represented by a droplet. We also construct hairy black droplets associated to a low-temperature scalar condensation instability and show that they are thermodynamically preferred to their hairless counterparts.

  15. 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...... 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...... 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....

  16. Chemical composition of essential oil from ripe fruit of Schinus terebinthifolius Raddi and evaluation of its activity against wild strains of hospital origin.

    Science.gov (United States)

    Cole, E R; dos Santos, R B; Lacerda Júnior, V; Martins, J D L; Greco, S J; Cunha Neto, A

    2014-01-01

    The essential oil (EO) composition of ripe fruit of S. terebinthifolius Raddi was analyzed by GC-MS. The oil extraction yielded 6.54 ± 1.06% (w/w). Seventeen compounds were identified, accounting for 91.15% of the total oil, where monoterpenes constituted the main chemical class (85.81%), followed by sesquiterpenes (5.34%). The major monoterpene identified was δ-3-carene (30.37%), followed by limonene (17.44%), α-phellandrene (12.60%) and α-pinene (12.59%). Trans-caryophyllene (1.77%) was the major sesquiterpene identified. The antibacterial activity of the essential oil was evaluated against wild strains of hospital origin (Escherichia coli, Pseudomonas sp., Klebsiella oxytoca, Corynebacterium sp., Staphylococcus aureus, Enterobacter sp., Enterobacter agglomerans, Bacillus sp., Nocardia sp. and Streptococcus group D). The essential oil of the ripe fruit of S. terebinthifolius Raddi has shown to be active against all tested wild strains, with minimum inhibitory concentration ranging from 3.55 μg/mL to 56.86 μg/mL. However, it has revealed some differences in susceptibility: the general, Gram-positive species showed greater sensitivity to the action of EO, which is probably due to the lower structural complexity of their cell walls.

  17. Antioxidant and Antiplatelet Activities in Extracts from Green and Fully Ripe Tomato Fruits (Solanum lycopersicum) and Pomace from Industrial Tomato Processing

    Science.gov (United States)

    Fuentes, Eduardo; Carle, Reinhold; Astudillo, Luis; Guzmán, Luis; Gutiérrez, Margarita; Carrasco, Gilda; Palomo, Iván

    2013-01-01

    The consumption of fruits and vegetables is accepted to be one of the strategies to reduce risk factors for these diseases. The aim of this study was to examine potential relationships between the antioxidant and the antiplatelet activities in green mature and fully ripe (red) tomatoes and of lycopene-rich byproducts of tomato paste processing such as pomace. The total phenol content of tomato components was the highest in peels, pulp, and in the mucilaginous myxotesta covering the tomato seeds with values 36.9 ± 0.8, 33.3 ± 00.5, and 17.6 ± 0.9 mg GAE/100 g, respectively (P < 0.05). Tomato peels had the highest antioxidant activity, both, as measured by the FRAP (46.9 ± 0.9 μmol Fe+2/g, P < 0.05) and the DPPH assays (97.4 ± 0.2%, 1000 μg/mL, P < 0.05). Pomace extracts showed the highest antiplatelet activity induced by ADP, collagen, TRAP-6, and arachidonic acid. While the maturation stage of the tomato fruit affected the antioxidant effect, antiplatelet activity was independent of fruit ripeness. Finally, based on the present results, tomato and its byproducts may be considered as a valuable source of antioxidant and antiplatelet activities. PMID:23476707

  18. Antioxidant and Antiplatelet Activities in Extracts from Green and Fully Ripe Tomato Fruits (Solanum lycopersicum and Pomace from Industrial Tomato Processing

    Directory of Open Access Journals (Sweden)

    Eduardo Fuentes

    2013-01-01

    Full Text Available The consumption of fruits and vegetables is accepted to be one of the strategies to reduce risk factors for these diseases. The aim of this study was to examine potential relationships between the antioxidant and the antiplatelet activities in green mature and fully ripe (red tomatoes and of lycopene-rich byproducts of tomato paste processing such as pomace. The total phenol content of tomato components was the highest in peels, pulp, and in the mucilaginous myxotesta covering the tomato seeds with values 36.9±0.8, 33.3±00.5, and 17.6±0.9 mg GAE/100 g, respectively (P<0.05. Tomato peels had the highest antioxidant activity, both, as measured by the FRAP (46.9±0.9 μmol Fe+2/g, P<0.05 and the DPPH assays (97.4±0.2%, 1000 μg/mL, P<0.05. Pomace extracts showed the highest antiplatelet activity induced by ADP, collagen, TRAP-6, and arachidonic acid. While the maturation stage of the tomato fruit affected the antioxidant effect, antiplatelet activity was independent of fruit ripeness. Finally, based on the present results, tomato and its byproducts may be considered as a valuable source of antioxidant and antiplatelet activities.

  19. The Black Black Woman and the Black Middle Class.

    Science.gov (United States)

    Jeffers, Trellie

    1981-01-01

    Reprint of a 1973 article that describes the discrimination that particularly dark-skinned Black women suffer, especially at the hands of a color-conscious Black middle class. Calls for dark women to look to the African appearance and working-class roots as sources of pride and strength. (GC)

  20. Evolution of biométrie parameters and chemical composition of olives from the Moroccan Picholine variety during fruit ripeness

    Directory of Open Access Journals (Sweden)

    Ajana, H.

    1999-02-01

    Full Text Available The evolution of the maturity index during the ripeness of olives from the Moroccan Picholine variety did not show any significant variation before the middle of September. After this date it began the growing and reached the maximum value (4.7 at the middle of January. The weight of olives increased continuously from June to November, and remained constant over two months beyond the maximal value of 3.95g (November and December. The weight of the olive kernels was constant during all the sampling period. The olive dimensions (length and width showed similar trend as the olive weight. The polar lipid fraction of the oil predominated over the neutral one during June and July and after this date, the neutral fraction prevailed. The maximum value was reached in December. The protein content decreased from 4.6 to 2.3%. Ash content grow from 2.72 to 5.57%. The chlorophyll content in the oils decrease progressively and showed an inverse correlation with the maturity index. The phosphorus content diminished until September and then continued to be constant.

    La evolución del índice de madurez durante la maduración de aceitunas de la variedad Picholine marroquí no mostró variación significativa antes de mediados de septiembre. Después de esta fecha comenzó el crecimiento y alcanzó su valor máximo (4.7 a mediados de enero. El peso de las aceitunas aumentó continuamente desde junio hasta noviembre y se estabilizó durante dos meses más allá del valor máximo de 3.95g (noviembre y diciembre. El peso del hueso de las aceitunas permaneció constante durante todo el período de muestreo. Las dimensiones de las aceitunas (longitud y anchura tuvieron tendencias similares a las del peso de la aceituna. La fracción lipídica polar del aceite predominó sobre la neutra durante los meses de junio y julio, para después de esta fecha prevalecer la fracción neutra alcanzando su valor máximo en el mes de diciembre. El contenido en prote

  1. Black hole hair removal

    Science.gov (United States)

    Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

    2009-07-01

    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.

  2. Black Hole Hair Removal

    CERN Document Server

    Banerjee, Nabamita; 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.

  3. 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.

  4. Black Hole Thermodynamics

    Science.gov (United States)

    Israel, Werner

    This chapter reviews the conceptual developments on black hole thermodynamics and the attempts to determine the origin of black hole entropy in terms of their horizon area. The brick wall model and an operational approach are discussed. An attempt to understand at the microlevel how the quantum black hole acquires its thermal properties is included. The chapter concludes with some remarks on the extension of these techniques to describing the dynamical process of black hole evaporation.

  5. Life inside black holes

    CERN Document Server

    Dokuchaev, V I

    2012-01-01

    We consider test planet and photon orbits of the third kind inside a black hole, which are stable, periodic and neither come out of the black hole nor terminate at the singularity. Interiors of supermassive black holes may be inhabited by advanced civilizations living on planets with the third-kind orbits. In principle, one can get information from the interiors of black holes by observing their white hole counterparts.

  6. Charged Lifshitz Black Holes

    OpenAIRE

    Dehghani, M. H.; Pourhasan, R.; Mann, R. B.

    2011-01-01

    We investigate modifications of the Lifshitz black hole solutions due to the presence of Maxwell charge in higher dimensions for arbitrary $z$ and any topology. We find that the behaviour of large black holes is insensitive to the topology of the solutions, whereas for small black holes significant differences emerge. We generalize a relation previously obtained for neutral Lifshitz black branes, and study more generally the thermodynamic relationship between energy, entropy, and chemical pot...

  7. Monopole black hole skyrmions

    OpenAIRE

    Moss, I. 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.

  8. Marketing for Black Alums.

    Science.gov (United States)

    Harris, Tracy A.

    1994-01-01

    Considers need for colleges and universities to develop effective marketing plan for recruitment of black students. Highlights advantages of designing marketing plan for recruitment of black alumni to assist in recruitment and retention of black students. Identifies key indicators that often hinder institutions in their recruitment of black…

  9. 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

  10. Crystallization and preliminary X-ray diffraction studies of NP24-I, an isoform of a thaumatin-like protein from ripe tomato fruits

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Raka; Chakrabarti, Chandana, E-mail: chandana.chakrabarti@saha.ac.in [Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata 700064 (India)

    2005-08-01

    A thaumatin-like antifungal protein, NP24-I, has been isolated from ripe tomato fruits. It was crystallized by the vapour-diffusion method and data were collected to 2.45 Å. The structure was solved by molecular replacement. NP24 is a 24 kDa (207-amino-acid) antifungal thaumatin-like protein (TLP) found in tomato fruits. An isoform of the protein, NP24-I, is reported to play a possible role in ripening of the fruit in addition to its antifungal properties. The protein has been isolated and purified and crystallized by the hanging-drop vapour-diffusion method. The crystals belong to the tetragonal space group P4{sub 3}, with unit-cell parameters a = b = 61.01, c = 62.90 Å and one molecule per asymmetric unit. X-ray diffraction data were processed to a resolution of 2.45 Å and the structure was solved by molecular replacement.

  11. Effect of cold storage on larval and adult Anastrepha ludens (Diptera: Tephritidae) viability in commercially ripe, artificially infested Persea americana 'Hass'.

    Science.gov (United States)

    Aluja, M; Díaz-Fleischer, F; Arredondo, J; Valle-Mora, J; Rull, J

    2010-12-01

    Commercially ripe 'Hass' avocados, Persea americana Mill, artificially exposed to wild Anastrepha ludens (Loew) (Diptera: Tephritidae) females 24 h after harvest were placed in a cold storage facility to determine the effect of low temperature on larval survival and adult viability. Fruit were left for 3, 6, 9, and 12 d in a cold room at 5 degrees C followed by a 20-25-d period at ambient temperature to allow for larval development and pupation. Hass avocados and grapefruit, Citrus paradisi Macfadyen, maintained at ambient temperature served as controls. Overall, only 0.23% of the Hass avocados and 19.30% of the grapefruit were infested. The number of infested fruit increased with decreasing exposure time to cold. Puparia from cold-treated Hass avocados were significantly smaller than those stemming from cold-treated grapefruit. Hass avocados exposed for 12 d to 5 degrees C yielded no puparia, and those exposed for 6 and 9 d yielded 22 and two puparia, respectively, but no adults. Although Hass avocados exposed to cold temperature for 3 d yielded adults that reached sexual maturity (N = 16), females laid inviable eggs. Grapefruit exposed to cold for 12 d yielded normal-sized puparia (but no adults), whereas those exposed over 9 d yielded females able to lay viable eggs. We conclude that exposing fruit to cold storage after packing and during transport represents an effective risk-mitigating procedure in the highly improbable event that a gravid A. ludens female might lay eggs in a commercially ripe Hass avocado that had been left unprotected in a packinghouse.

  12. Influence of alternating air injection on the color and “alambrado” of natural black olives cv. Arauco, as compared with the traditional Argentine method

    OpenAIRE

    2015-01-01

    Ripe black olives cv. Arauco were processed under different conditions to evaluate the effects of alternating air injection (AI) on the color of olives and on spoilage known as “alambrado”, using a system based on the one patented by the “Instituto de la Grasa” (Sevilla, Spain), as compared with the traditional Argentine processing method, which consists of drying the olives in natural air (“extendido”) for 24 hours at 7, 14 and 21 days of fermentation. Four types of fermentation were used: b...

  13. On Accelerated Black Holes

    CERN Document Server

    Letelier, P S; Letelier, Patricio S.; Oliveira, Samuel R.

    1998-01-01

    The C-metric is revisited and global interpretation of some associated spacetimes are studied in some detail. Specially those with two event horizons, one for the black hole and another for the acceleration. We found that the spacetime fo an accelerated Schwarzschild black hole is plagued by either conical singularities or lack of smoothness and compactness of the black hole horizon. By using standard black hole thermodynamics we show that accelerated black holes have higher Hawking temperature than Unruh temperature. We also show that the usual upper bound on the product of the mass and acceleration parameters (<1/sqrt(27)) is just a coordinate artifact. The main results are extended to accelerated Kerr black holes. We found that they are not changed by the black hole rotation.

  14. Epidemiological importance of Solanum sisymbriifolium, S. nigrum and S. dulcamara as alternative hosts for Phytophthora infestans

    NARCIS (Netherlands)

    Flier, W.G.; Bosch, van den G.B.M.; Turkensteen, L.J.

    2003-01-01

    Lesions of Phytophthora infestans were found on woody nightshade (Solanum dulcamara), black nightshade (S. nigrum) and S. sisymbriifolium during a nationwide late blight survey in the Netherlands in 1999 and 2000. Pathogenicity and spore production of P. infestans isolates collected from potato (S.

  15. Extremal Hairy Black Holes

    CERN Document Server

    Gonzalez, P A; Saavedra, Joel; Vasquez, Yerko

    2014-01-01

    We consider a gravitating system consisting of a scalar field minimally coupled to gravity with a self-interacting potential and an U(1) electromagnetic field. Solving the coupled Einstein-Maxwell-scalar system we find exact hairy charged black hole solutions with the scalar field regular everywhere. We go to the zero temperature limit and we study the effect of the scalar field on the near horizon geometry of an extremal black hole. We find that except a critical value of the charge of the black hole there is also a critical value of the charge of the scalar field beyond of which the extremal black hole is destabilized. We study the thermodynamics of these solutions and we find that if the space is flat then at low temperature the Reissner-Nordstr\\"om black hole is thermodynamically preferred, while if the space is AdS the hairy charged black hole is thermodynamically preferred at low temperature.

  16. 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.

  17. Black Branes as Piezoelectrics

    CERN Document Server

    Armas, Jay; Obers, Niels A

    2012-01-01

    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.

  18. 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.

  19. Perturbations around black holes

    CERN Document Server

    Wang, B

    2005-01-01

    Perturbations around black holes have been an intriguing topic in the last few decades. They are particularly important today, since they relate to the gravitational wave observations which may provide the unique fingerprint of black holes' existence. Besides the astrophysical interest, theoretically perturbations around black holes can be used as testing grounds to examine the proposed AdS/CFT and dS/CFT correspondence.

  20. Asymptotic Black Holes

    CERN Document Server

    Ho, Pei-Ming

    2016-01-01

    Following earlier works on the KMY model of black-hole formation and evaporation, we construct the metric for a matter sphere in gravitational collapse, with the back-reaction of pre-Hawking radiation taken into consideration. The mass distribution and collapsing velocity of the matter sphere are allowed to have an arbitrary radial dependence. We find that a generic gravitational collapse asymptote to a universal configuration which resembles a black hole but without horizon. This approach clarifies several misunderstandings about black-hole formation and evaporation, and provides a new model for black-hole-like objects in the universe.

  1. Asymptotic black holes

    Science.gov (United States)

    Ho, Pei-Ming

    2017-04-01

    Following earlier works on the KMY model of black-hole formation and evaporation, we construct the metric for a matter sphere in gravitational collapse, with the back-reaction of pre-Hawking radiation taken into consideration. The mass distribution and collapsing velocity of the matter sphere are allowed to have an arbitrary radial dependence. We find that a generic gravitational collapse asymptote to a universal configuration which resembles a black hole but without horizon. This approach clarifies several misunderstandings about black-hole formation and evaporation, and provides a new model for black-hole-like objects in the universe.

  2. Black Hole Thermodynamics

    CERN Document Server

    Carlip, S

    2014-01-01

    The discovery in the early 1970s that black holes radiate as black bodies has radically affected our understanding of general relativity, and offered us some early hints about the nature of quantum gravity. In this chapter I will review the discovery of black hole thermodynamics and summarize the many independent ways of obtaining the thermodynamic and (perhaps) statistical mechanical properties of black holes. I will then describe some of the remaining puzzles, including the nature of the quantum microstates, the problem of universality, and the information loss paradox.

  3. Arbitrators, Blacks and Discipline

    Science.gov (United States)

    Jennings, Kenneth

    1975-01-01

    A discussion of the handling of disciplinary problems of black employees concludes that management should be concerned because of the effect that grievance resolution may have on the company's overall employee discipline program and the additional appeal alternatives available to the black employee. (Author/EA)

  4. Perturbing supersymmetric black hole

    CERN Document Server

    Onozawa, H; Mishima, T; Ishihara, H; Onozawa, Hisashi; Okamura, Takashi; Mishima, Takashi; Ishihara, Hideki

    1996-01-01

    An investigation of the perturbations of the Reissner-Nordstr\\"{o}m black hole in the N=2 supergravity is presented. In the extreme case, the black hole responds to the perturbation of each field in the same manner. This is possibly because we can match the modes of the graviton, gravitino, and photon using supersymmetry transformations.

  5. Black Hole Dynamic Potentials

    Indian Academy of Sciences (India)

    Koustubh Ajit Kabe

    2012-09-01

    In the following paper, certain black hole dynamic potentials have been developed definitively on the lines of classical thermodynamics. These potentials have been refined in view of the small differences in the equations of the laws of black hole dynamics as given by Bekenstein and those of thermodynamics. Nine fundamental black hole dynamical relations have been developed akin to the four fundamental thermodynamic relations of Maxwell. The specific heats , and , have been defined. For a black hole, these quantities are negative. The d equation has been obtained as an application of these fundamental relations. Time reversible processes observing constancy of surface gravity are considered and an equation connecting the internal energy of the black hole , the additional available energy defined as the first free energy function , and the surface gravity , has been obtained. Finally as a further application of the fundamental relations, it has been proved for a homogeneous gravitational field in black hole space times or a de Sitter black hole that $C_{\\Omega,\\Phi}-C_{J,Q}=\\kappa \\left[\\left(\\dfrac{\\partial J}{\\partial \\kappa}\\right)_{\\Omega,\\Phi}\\left(\\dfrac{\\partial \\Omega}{\\partial \\kappa}\\right)_{J,Q}+\\left(\\dfrac{\\partial Q}{\\partial \\kappa}\\right)_{\\Omega,\\Phi}\\left(\\dfrac{\\partial\\Phi}{\\partial \\kappa}\\right)_{J,Q}\\right]$. This is dubbed as the homogeneous fluid approximation in context of the black holes.

  6. Black holes matter

    DEFF Research Database (Denmark)

    Kragh, Helge Stjernholm

    2016-01-01

    Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015).......Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015)....

  7. Scattering by Black Holes

    CERN Document Server

    Andersson, N

    2000-01-01

    This is a chapter on Black-hole Scattering that was commissioned for an Encyclopaedia on Scattering edited by Pike and Sabatier, to be published by Academic Press. The chapter surveys wave propagation in black-hole spacetimes, diffraction effects in wave scattering, resonances, quasinormal modes and related topics.

  8. Blacks and Trade Unionism

    Science.gov (United States)

    Ashenfelter, Orley

    1975-01-01

    This testimony, before a public hearing of the New York City Commission on Human Rights in May 1974, focuses on two issues: (1) the effect of the presence of trade unionism on the position of black workers in the labor market relative to white workers; and (2) the effect of federal government efforts to increase the position of black workers…

  9. Fifty shades of black

    Science.gov (United States)

    Cartwright, Jon

    2015-11-01

    Creating dark materials that prevent reflections has become hot competition recently, with Guinness World Records having to keep revising the darkest substance yet created. But depending on who's asking, the best black may not be the blackest black, as Jon Cartwright discovers.

  10. Cosmological Black Holes

    CERN Document Server

    Stornaiolo, C

    2002-01-01

    In this letter we propose the existence of low density black holes and discuss its compatibility with the cosmological observations. The origin of these black holes can be traced back to the collapse of long wavelength cosmological perturbations during the matter dominated era, when the densities are low enough to neglect any internal and thermal pressure. By introducing a threshold density $\\hat{\\rho}$ above which pressure and non-gravitational interactions become effective, we find the highest wavelength for the perturbations that can reach an equilibrium state instead of collapsing to a black hole. The low density black holes introduced here, if they exist, can be observed through weak and strong gravitational lensing effects. Finally we observe that we obtained here a cosmological model which is capable to explain in a qualitative way the void formation together with the value $\\Omega=1$. But we remark that it needs to be improved by considering non spherical symmetric black holes.

  11. Primordial Black Hole Baryogenesis

    CERN Document Server

    Baumann, D; Turok, N G; Baumann, Daniel; Steinhardt, Paul J.; Turok, Neil

    2007-01-01

    We reconsider the possibility that the observed baryon asymmetry was generated by the evaporation of primordial black holes that dominated the early universe. We present a simple derivation showing that the baryon asymmetry is insensitive to the initial black hole density and the cosmological model but is sensitive to the temperature-dependence of the CP and baryon-violating (or lepton-violating) interactions. We also consider the possibility that black holes stop evaporating and form Planck-mass remnants that act as dark matter. We show that primordial black holes cannot simultaneously account for both the observed baryon asymmetry and the (remnant) dark matter density unless the magnitude of CP violation is much greater than expected from most particle physics models. Finally, we apply these results to ekpyrotic/cyclic models, in which primordial black holes may form when branes collide. We find that obtaining the observed baryon asymmetry is compatible with the other known constraints on parameters.

  12. Lifshitz Topological Black Holes

    CERN Document Server

    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.

  13. Comparative transcriptome analysis of unripe and mid-ripe fruit of Mangifera indica (var. “Dashehari”) unravels ripening associated genes

    Science.gov (United States)

    Srivastava, Smriti; Singh, Rajesh K.; Pathak, Garima; Goel, Ridhi; Asif, Mehar Hasan; Sane, Aniruddha P.; Sane, Vidhu A.

    2016-01-01

    Ripening in mango is under a complex control of ethylene. In an effort to understand the complex spatio-temporal control of ripening we have made use of a popular N. Indian variety “Dashehari” This variety ripens from the stone inside towards the peel outside and forms jelly in the pulp in ripe fruits. Through a combination of 454 and Illumina sequencing, a transcriptomic analysis of gene expression from unripe and midripe stages have been performed in triplicates. Overall 74,312 unique transcripts with ≥1 FPKM were obtained. The transcripts related to 127 pathways were identified in “Dashehari” mango transcriptome by the KEGG analysis. These pathways ranged from detoxification, ethylene biosynthesis, carbon metabolism and aromatic amino acid degradation. The transcriptome study reveals differences not only in expression of softening associated genes but also those that govern ethylene biosynthesis and other nutritional characteristics. This study could help to develop ripening related markers for selective breeding to reduce the problems of excess jelly formation during softening in the “Dashehari” variety. PMID:27586495

  14. Black Hole Critical Phenomena Without Black Holes

    CERN Document Server

    Liebling, S L

    2000-01-01

    Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. Power-law mass scaling, aspects of universality, and self-similarity have now been found for a large variety of models. However, questions remain. Here I briefly review critical phenomena, discuss some recent results, and describe a model which demonstrates similar phenomena without gravity.

  15. 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…

  16. 狗尾草果实中总鞣质的提取和含量测定%EXTRACTION AND DETERMINATION OF TOTAL TANNIN FROM SETARIA VIRIDIS( L. ) BEAUV.RIPE FRUITS

    Institute of Scientific and Technical Information of China (English)

    张爱武; 罗素琴; 刘乐乐; 吴宁远; 王来兵; 于姝燕; 张国萍

    2012-01-01

    Objective: To extract total tannin from Setaria viridis (L. ) Beaux, ripe fruits and deter mination the content of total tannin. Methods: It was adopted the optimum ultrasonic extraction tech nique to extract the total tannin from Setaira viridis (L. ) Beauv. Ripe fruits. Compleximetry was applied to determine the content of total tannin. Results: The content of total tannin was 0.4650%. Conclu sion :Ultrasonic extraction technique is simple and rapid,Content determination of complexometric titra tion method is safe and reliable. The method was available for extraction and content determination of total tannin from Setaria viridis (L. ) Beauv. Ripe fruits.%目的:从狗尾草果实中提取总鞣质并测定其含量.方法:采用超声波法提取狗尾革果实的总鞣质,用络合滴定法测定其总鞣质的含量.结果:狗尾草果实总鞣质的含量为0.4650%.结论:采用超声法提取操作程序简便、迅速,络合滴定法含量测定方法安全可靠,准确度和精密度较高,可用于狗尾草果实中总鞣质的提取及含量测定.

  17. Black holes new horizons

    CERN Document Server

    Hayward, Sean Alan

    2013-01-01

    Black holes, once just fascinating theoretical predictions of how gravity warps space-time according to Einstein's theory, are now generally accepted as astrophysical realities, formed by post-supernova collapse, or as supermassive black holes mysteriously found at the cores of most galaxies, powering active galactic nuclei, the most powerful objects in the universe. Theoretical understanding has progressed in recent decades with a wider realization that local concepts should characterize black holes, rather than the global concepts found in textbooks. In particular, notions such as trapping h

  18. Scalarized hairy black holes

    Energy Technology Data Exchange (ETDEWEB)

    Kleihaus, Burkhard, E-mail: b.kleihaus@uni-oldenburg.de [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Kunz, Jutta [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Yazadjiev, Stoytcho [Department of Theoretical Physics, Faculty of Physics, Sofia University, Sofia 1164 (Bulgaria)

    2015-05-11

    In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.

  19. Scalarized hairy black holes

    Directory of Open Access Journals (Sweden)

    Burkhard Kleihaus

    2015-05-01

    Full Text Available In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.

  20. Black Hole Entropy

    OpenAIRE

    P. Mitra

    1994-01-01

    In the talk different definitions of the black hole entropy are discussed and compared. It is shown that the Bekenstein-Hawking entropy $S^{BH}$ (defined by the response of the free energy of a system containing a black hole on the change of the temperature) differs from the statistical- mechanical entropy $S^{SM}=-\\mbox{Tr}(\\hat{\\rho}\\ln \\hat{\\rho})$ (defined by counting internal degrees of freedom of a black hole). A simple explanation of the universality of the Bekenstein-Hawking entropy (...

  1. Black hole entropy

    CERN Document Server

    Frolov, V

    1994-01-01

    In the talk different definitions of the black hole entropy are discussed and compared. It is shown that the Bekenstein-Hawking entropy S^{BH} (defined by the response of the free energy of a system containing a black hole on the change of the temperature) differs from the statistical- mechanical entropy S^{SM}=-\\mbox{Tr}(\\hat{\\rho}\\ln \\hat{\\rho}) (defined by counting internal degrees of freedom of a black hole). A simple explanation of the universality of the Bekenstein-Hawking entropy (i.e. its independence of the number and properties of the fields which might contribute to S^{SM}) is given.

  2. Primordial Black Holes

    CERN Document Server

    MacGibbon, Jane H; Linnemann, J T; Marinelli, S S; Stump, D; Tollefson, K

    2015-01-01

    Primordial Black Holes (PBHs) are of interest in many cosmological contexts. PBHs lighter than about 1012 kg are predicted to be directly detectable by their Hawking radiation. This radiation should produce both a diffuse extragalactic gamma-ray background from the cosmologically-averaged distribution of PBHs and gamma-ray burst signals from individual light black holes. The Fermi, Milagro, Veritas, HESS and HAWC observatories, in combination with new burst recognition methodologies, offer the greatest sensitivity for the detection of such black holes or placing limits on their existence.

  3. Feminism and Black Women's Studies.

    Science.gov (United States)

    Hooks, Bell

    1989-01-01

    Women's studies programs have largely ignored Black women. Until Black women's studies courses are developed, feminist scholarship on Black women will not advance, and the contributions of Black women to women's rights movements and African American literature and scholarship may be neglected. (DM)

  4. The Price of "Black Dominance."

    Science.gov (United States)

    Hoberman, John

    2000-01-01

    Discusses the harmful effects of stereotyping black males as athletes, noting that over-identification with athletes and the world of physical performance limits black children's development by discouraging academic achievement. Examines the negative influence of mass media focus on black athletes, rappers, and stylized ghetto blackness. Discusses…

  5. 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.

  6. Janus black holes

    Science.gov (United States)

    Bak, Dongsu; Gutperle, Michael; Janik, Romuald A.

    2011-10-01

    In this paper Janus black holes in A dS 3 are considered. These are static solutions of an Einstein-scalar system with broken translation symmetry along the horizon. These solutions are dual to interface conformal field theories at finite temperature. An approximate solution is first constructed using perturbation theory around a planar BTZ blackhole. Numerical and exact solutions valid for all sets of parameters are then found and compared. Using the exact solution the thermodynamics of the system is analyzed. The entropy associated with the Janus black hole is calculated and it is found that the entropy of the black Janus is the sum of the undeformed black hole entropy and the entanglement entropy associated with the defect.

  7. Black Rail Pilot Survey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Aural surveys using tape recorded calls proved to be an efficient and effective way to survey large expanses of shallow marsh for black rails (Laterallus...

  8. Black Friday = Broget Branding?

    DEFF Research Database (Denmark)

    Hansen, Heidi

    2015-01-01

    Black Friday er et godt eksempel på, hvordan ikke kun produktbrands og corporate brands rejser på tværs af landegrænser, men også traditioner som Halloween, Valentines Day og i dette tilfælde den ultimative tilbuds-fredag, som i USA går under navnet Black Friday. Men hvad er Black Friday i Danmark......? Essensen ved Black Friday er lave priser, og det er der ved første øjekast ikke mange brandingmuligheder forbundet ved, hvis man forstår branding som en måde at skabe ekstra værdi omkring sit produkt eller sin virksomhed. Som brand bliver man dog alligevel nødt til at forholde sig til konceptet, da det er...

  9. Modelling quantum black hole

    CERN Document Server

    Govindarajan, T R

    2016-01-01

    Novel bound states are obtained for manifolds with singular potentials. These singular potentials require proper boundary conditions across boundaries. The number of bound states match nicely with what we would expect for black holes. Also they serve to model membrane mechanism for the black hole horizons in simpler contexts. The singular potentials can also mimic expanding boundaries elegantly, there by obtaining appropriately tuned radiation rates.

  10. Helical superconducting black holes.

    Science.gov (United States)

    Donos, Aristomenis; Gauntlett, Jerome P

    2012-05-25

    We construct novel static, asymptotically five-dimensional anti-de Sitter black hole solutions with Bianchi type-VII(0) symmetry that are holographically dual to superconducting phases in four spacetime dimensions with a helical p-wave order. We calculate the precise temperature dependence of the pitch of the helical order. At zero temperature the black holes have a vanishing entropy and approach domain wall solutions that reveal homogenous, nonisotropic dual ground states with an emergent scaling symmetry.

  11. Black Is Cool!

    Institute of Scientific and Technical Information of China (English)

    Dorine; Houston

    1997-01-01

    Do you remember the colors the college freshmen dyed their hair when you were here? Turquoise, orange, bright yellow.... Things have changed. Black has (?)ome the color of choice among the young people. Young men and women alike dye their hair coal black. The women let their hair grow very long. and it hangs straight and stringy down their backs. The young men leave it long on

  12. Braneworld black holes

    CERN Document Server

    Gregory, Ruth

    2008-01-01

    In these lectures, I give an introduction to and overview of braneworlds and black holes in the context of warped compactifications. I first describe the general paradigm of braneworlds, and introduce the Randall-Sundrum model. I discuss braneworld gravity, both using perturbation theory, and also non perturbative results. I then discuss black holes on the brane, the obstructions to finding exact solutions, and ways of tackling these difficulties. I describe some known solutions, and conclude with some open questions and controversies.

  13. Black Hole Induced Ejections

    OpenAIRE

    Pelletier, G.

    2004-01-01

    Black Holes generate a particular kind of environments dominated by an accretion flow which concentrates a magnetic field. The interplay of gravity and magnetism creates this paradoxical situation where relativistic ejection is allowed and consequently high energy phenomena take place. Therefore Black Holes, which are very likely at the origin of powerfull astrophysical phenomena such as AGNs, micro- quasars and GRBs where relativistic ejections are observed, are at the heart of high energy a...

  14. Cosmic censorship inside black holes

    CERN Document Server

    Thorlacius, L

    2006-01-01

    A simple argument is given that a traversable Cauchy horizon inside a black hole is incompatible with unitary black hole evolution. The argument assumes the validity of black hole complementarity and applies to a generic black hole carrying angular momentum and/or charge. In the second part of the paper we review recent work on the semiclassical geometry of two-dimensional charged black holes.

  15. Black hole critical phenomena without black holes

    Indian Academy of Sciences (India)

    Steven L Liebling

    2000-10-01

    Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. Power-law mass scaling, aspects of universality, and self-similarity have now been found for a large variety of models. However, questions remain. Here I briefly review critical phenomena, discuss some recent results, and describe a model which demonstrates similar phenomena without gravity.

  16. Charged Galileon black holes

    Science.gov (United States)

    Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar

    2015-05-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematically compatible with the field equations. This opens up the possibility for novel searches of hairy black holes in a far more general setting of Horndeski theory.

  17. Ultramassive Black Hole Coalescence

    CERN Document Server

    Khan, Fazeel; 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 NGC1277 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 NGC1277 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, gr...

  18. Movement of Salmonella serovar Typhimurium and E. coli O157:H7 to Ripe Tomato Fruit Following Various Routes of Contamination.

    Science.gov (United States)

    Deering, Amanda J; Jack, Dan R; Pruitt, Robert E; Mauer, Lisa J

    2015-11-05

    Salmonella serovars have been associated with the majority of foodborne illness outbreaks involving tomatoes, and E. coli O157:H7 has caused outbreaks involving other fresh produce. Contamination by both pathogens has been thought to originate from all points of the growing and distribution process. To determine if Salmonella serovar Typhimurium and E. coli O157:H7 could move to the mature tomato fruit of different tomato cultivars following contamination, three different contamination scenarios (seed, leaf, and soil) were examined. Following contamination, each cultivar appeared to respond differently to the presence of the pathogens, with most producing few fruit and having overall poor health. The Micro-Tom cultivar, however, produced relatively more fruit and E. coli O157:H7 was detected in the ripe tomatoes for both the seed- and leaf- contaminated plants, but not following soil contamination. The Roma cultivar produced fewer fruit, but was the only cultivar in which E. coli O157:H7 was detected via all three routes of contamination. Only two of the five cultivars produced tomatoes following seed-, leaf-, and soil- contamination with Salmonella Typhimurium, and no Salmonella was found in any of the tomatoes. Together these results show that different tomato cultivars respond differently to the presence of a human pathogen, and for E. coli O157:H7, in particular, tomato plants that are either contaminated as seeds or have a natural opening or a wound, that allows bacteria to enter the leaves can result in plants that have the potential to produce tomatoes that harbor internalized pathogenic bacteria.

  19. Movement of Salmonella serovar Typhimurium and E. coli O157:H7 to Ripe Tomato Fruit Following Various Routes of Contamination

    Directory of Open Access Journals (Sweden)

    Amanda J. Deering

    2015-11-01

    Full Text Available Salmonella serovars have been associated with the majority of foodborne illness outbreaks involving tomatoes, and E. coli O157:H7 has caused outbreaks involving other fresh produce. Contamination by both pathogens has been thought to originate from all points of the growing and distribution process. To determine if Salmonella serovar Typhimurium and E. coli O157:H7 could move to the mature tomato fruit of different tomato cultivars following contamination, three different contamination scenarios (seed, leaf, and soil were examined. Following contamination, each cultivar appeared to respond differently to the presence of the pathogens, with most producing few fruit and having overall poor health. The Micro-Tom cultivar, however, produced relatively more fruit and E. coli O157:H7 was detected in the ripe tomatoes for both the seed- and leaf- contaminated plants, but not following soil contamination. The Roma cultivar produced fewer fruit, but was the only cultivar in which E. coli O157:H7 was detected via all three routes of contamination. Only two of the five cultivars produced tomatoes following seed-, leaf-, and soil- contamination with Salmonella Typhimurium, and no Salmonella was found in any of the tomatoes. Together these results show that different tomato cultivars respond differently to the presence of a human pathogen, and for E. coli O157:H7, in particular, tomato plants that are either contaminated as seeds or have a natural opening or a wound, that allows bacteria to enter the leaves can result in plants that have the potential to produce tomatoes that harbor internalized pathogenic bacteria.

  20. Salt stress-induced production of reactive oxygen- and nitrogen species and cell death in the ethylene receptor mutant Never ripe and wild type tomato roots.

    Science.gov (United States)

    Poór, Péter; Kovács, Judit; Borbély, Péter; Takács, Zoltán; Szepesi, Ágnes; Tari, Irma

    2015-12-01

    The salt stress triggered by sublethal, 100 mM and lethal, 250 mM NaCl induced ethylene production as well as rapid accumulation of superoxide radical and H2O2 in the root tips of tomato (Solanum lycopersicum cv. Ailsa Craig) wild type and ethylene receptor mutant, Never ripe (Nr/Nr) plants. In the wild type plants superoxide accumulation confined to lethal salt concentration while H2O2 accumulated more efficiently under sublethal salt stress. However, in Nr roots the superoxide production was higher and unexpectedly, H2O2 level was lower than in the wild type under sublethal salt stress. Nitric oxide production increased significantly under sublethal and lethal salt stress in both genotypes especially in mutant plants, while peroxynitrite accumulated significantly under lethal salt stress. Thus, the nitro-oxidative stress may be stronger in Nr roots, which leads to the programmed death of tissues, characterized by the DNA and protein degradation and loss of cell viability under moderate salt stress. In Nr mutants the cell death was induced in the absence of ethylene perception. Although wild type roots could maintain their potassium content under moderate salt stress, K(+) level significantly declined leading to small K(+)/Na(+) ratio in Nr roots. Thus Nr mutants were more sensitive to salt stress than the wild type and the viability of root cells decreased significantly under moderate salt stress. These changes can be attributed to a stronger ionic stress due to the K(+) loss from the root tissues.

  1. 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

  2. Thermodynamic black di-rings

    CERN Document Server

    Iguchi, Hideo

    2010-01-01

    Previously the five dimensional $S^1$-rotating black rings have been superposed in concentric way by some solitonic methods and regular systems of two $S^1$-rotating black rings were constructed by the authors and then Evslin and Krishnan (we called these solutions black di-rings). In this place we show some characteristics of the solutions of five dimensional black di-rings, especially in thermodynamic equilibrium. After the summary of the di-ring expressions and their physical quantities, first we comment on the equivalence of the two different solution-sets of the black di-rings. Then the existence of thermodynamic black di-rings are shown, in which both iso-thermality and iso-rotation between the inner black ring and the outer black ring are realized. We also give detailed analysis of peculiar properties of the thermodynamic black di-ring including discussion about a certain kind of thermodynamic stability (instability) of the system.

  3. Merging Black Holes

    Science.gov (United States)

    Centrella, Joan

    2009-05-01

    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.

  4. Charged Galileon black holes

    CERN Document Server

    Babichev, Eugeny; Hassaine, Mokhtar

    2015-01-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematic...

  5. Black Afrikaans: An alternative use

    Directory of Open Access Journals (Sweden)

    Anna P. Maritz

    2016-09-01

    Full Text Available This article provides a first look at the nature of the alternative functions of Black Afrikaans. These functions realise when Black Afrikaans is imitated by Afrikaans mother-tongue speakers. The functions of the alternative use of Black Afrikaans centre on: the social nature of the variety, sensitivity as a deciding role-player, identity, humour, inclusivity and exclusivity, language repertoire and similar variety. Furthermore, because of the direct relationship between Black Afrikaans, Pidginised Afrikaans and the imitation of Black Afrikaans, these varieties are compared to establish a starting point description for the imitation of Black Afrikaans, as the variety has not yet been described.

  6. Black Hole Induced Ejections

    CERN Document Server

    Pelletier, G

    2004-01-01

    Black Holes generate a particular kind of environments dominated by an accretion flow which concentrates a magnetic field. The interplay of gravity and magnetism creates this paradoxical situation where relativistic ejection is allowed and consequently high energy phenomena take place. Therefore Black Holes, which are very likely at the origin of powerfull astrophysical phenomena such as AGNs, micro- quasars and GRBs where relativistic ejections are observed, are at the heart of high energy astrophysics. The combination of General Relativity and Magneto-HydroDynamics (MHD) makes theory difficult; however great pionneers opened beautiful tracks in the seventies and left important problems to be solved for the next decades. These lectures will present the status of these issues. They have a tutorial aspect together with critical review aspect and contain also some new issues. Most of these lectures has been presented at the "School on Black Hole in the Universe" at Cargese, in May 2003.

  7. Turbulent black holes.

    Science.gov (United States)

    Yang, Huan; Zimmerman, Aaron; Lehner, Luis

    2015-02-27

    We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids.

  8. Merging Black Holes

    Science.gov (United States)

    Centrella, Joan

    2012-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics

  9. Black hole entropy quantization

    CERN Document Server

    Corichi, A; Fernandez-Borja, E; Corichi, Alejandro; Diaz-Polo, Jacobo; Fernandez-Borja, Enrique

    2006-01-01

    Ever since the pioneer works of Bekenstein and Hawking, black hole entropy has been known to have a quantum origin. Furthermore, it has long been argued by Bekenstein that entropy should be quantized in discrete (equidistant) steps given its identification with horizon area in (semi-)classical general relativity and the properties of area as an adiabatic invariant. This lead to the suggestion that black hole area should also be quantized in equidistant steps to account for the discrete black hole entropy. Here we shall show that loop quantum gravity, in which area is not quantized in equidistant steps can nevertheless be consistent with Bekenstein's equidistant entropy proposal in a subtle way. For that we perform a detailed analysis of the number of microstates compatible with a given area and show that an observed oscillatory behavior in the entropy-area relation, when properly interpreted yields an entropy that has discrete, equidistant values that are consistent with the Bekenstein framework.

  10. Black hole accretion discs

    CERN Document Server

    Lasota, Jean-Pierre

    2015-01-01

    This is an introduction to models of accretion discs around black holes. After a presentation of the non-relativistic equations describing the structure and evolution of geometrically thin accretion discs we discuss their steady-state solutions and compare them to observation. Next we describe in detail the thermal-viscous disc instability model and its application to dwarf novae for which it was designed and its X-ray irradiated-disc version which explains the soft X--ray transients, i.e. outbursting black-hole low-mass X-ray binaries. We then turn to the role of advection in accretion flow onto black holes illustrating its action and importance with a toy model describing both ADAFs and slim discs. We conclude with a presentation of the general-relativistic formalism describing accretion discs in the Kerr space-time.

  11. Tunneling Through Black Rings

    Institute of Scientific and Technical Information of China (English)

    ZHAO Liu

    2007-01-01

    Hawking radiation of black ring solutions to 5-dimensional Einstein-Maxwell-dilaton theory is analyzed by use of the Parikh-Wilczek tunneling method. To get the correct tunneling amplitude and emission rate, we adopt and develop the Angheben-Nadalini-Vanzo-Zerbini covariant approach to cover the effects of rotation and electronic discharge all at once, and the effect of back reaction is also taken into account. This constitutes a unified approach to the tunneling problem. Provided the first law of thermodynamics for black rings holds, the emission rate is proportional to the exponential of the change of Bekenstein-Hawking entropy. Explicit calculation for black ring temperatures agrees exactly with the results obtained via the classical surface gravity method and the quasi-local formalism.

  12. Black hole gravitohydromagnetics

    CERN Document Server

    Punsly, Brian

    2008-01-01

    Black hole gravitohydromagnetics (GHM) is developed from the rudiments to the frontiers of research in this book. GHM describes plasma interactions that combine the effects of gravity and a strong magnetic field, in the vicinity (ergosphere) of a rapidly rotating black hole. This topic was created in response to the astrophysical quest to understand the central engines of radio loud extragalactic radio sources. The theory describes a "torsional tug of war" between rotating ergospheric plasma and the distant asymptotic plasma that extracts the rotational inertia of the black hole. The recoil from the struggle between electromagnetic and gravitational forces near the event horizon is manifested as a powerful pair of magnetized particle beams (jets) that are ejected at nearly the speed of light. These bipolar jets feed large-scale magnetized plasmoids on scales as large as millions of light years (the radio lobes of extragalactic radio sources). This interaction can initiate jets that transport energy fluxes exc...

  13. The closest black holes

    CERN Document Server

    Fender, Rob; Heywood, Ian

    2013-01-01

    Starting from the assumption that there is a large population (> 10^8) of isolated, stellar-mass black holes (IBH) distributed throughout our galaxy, we consider the detectable signatures of accretion from the interstellar medium (ISM) that may be associated with such a population. We simulate the nearby (radius 250 pc) part of this population, corresponding to the closest ~35 000 black holes, using current best estimates of the mass distribution of stellar mass black holes combined with two models for the velocity distribution of stellar-mass IBH which bracket likely possibilities. We distribute this population of objects appropriately within the different phases of the ISM and calculate the Bondi-Hoyle accretion rate, modified by a further dimensionless efficiency parameter \\lambda. Assuming a simple prescription for radiatively inefficient accretion at low Eddington ratios, we calculate the X-ray luminosity of these objects, and similarly estimate the radio luminosity from relations found empirically for b...

  14. Horndeski black hole geodesics

    CERN Document Server

    Tretyakova, D A

    2016-01-01

    We examine geodesics for the scalar-tensor black holes in the Horndeski-Galileon framework. Our analysis shows that first kind relativistic orbits may not be present within some model parameters range. This is a highly pathological behavior contradicting to the black hole accretion and Solar System observations. We also present a new (although very similar to those previously known) solution, which contains the orbits we expect from a compact object, admits regular scalar field at the horizon and and can fit into the known stability criteria.

  15. Are Black Holes Springy?

    CERN Document Server

    Good, Michael R R

    2014-01-01

    A $(3+1)$-dimensional asymptotically flat Kerr black hole angular speed $\\Omega_+$ can be used to define an effective spring constant, $k=m\\Omega_+^2$. Its maximum value is the Schwarzschild surface gravity, $k = \\kappa $, which rapidly weakens as the black hole spins down and the temperature increases. The Hawking temperature is expressed in terms of the spring constant: $2\\pi T = \\kappa - k$. Hooke's law, in the extremal limit, provides the force $F = 1/4$, which is consistent with the conjecture of maximum force in general relativity.

  16. Acoustic black holes

    CERN Document Server

    Visser, M

    1999-01-01

    Acoustic propagation in a moving fluid provides a conceptually clean and powerful analogy for understanding black hole physics. As a teaching tool, the analogy is useful for introducing students to both General Relativity and fluid mechanics. As a research tool, the analogy helps clarify what aspects of the physics are kinematics and what aspects are dynamics. In particular, Hawking radiation is a purely kinematical effect, whereas black hole entropy is intrinsically dynamical. Finally, I discuss the fact that with present technology acoustic Hawking radiation is almost experimentally testable.

  17. Superfluid Black Holes

    CERN Document Server

    Hennigar, Robie A; Tjoa, Erickson

    2016-01-01

    We present what we believe is the first example of a "$\\lambda$-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid $^4$He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically AdS hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  18. Superfluid Black Holes.

    Science.gov (United States)

    Hennigar, Robie A; Mann, Robert B; Tjoa, Erickson

    2017-01-13

    We present what we believe is the first example of a "λ-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid ^{4}He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically anti-de Sitter hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  19. Characterizing Black Hole Mergers

    Science.gov (United States)

    Baker, John; Boggs, William Darian; Kelly, Bernard

    2010-01-01

    Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.

  20. Bulletproof Black Man

    DEFF Research Database (Denmark)

    Højer, Henrik

    2016-01-01

    Netflix’ kommende serie om den sorte Marvel-helt Luke Cage lander snart – midt i de aktuelle racekonflikter i USA. I GIF-anatomien "Bulletproof Black Man" sætter Henrik Højer serien ind i dens amerikanske kontekst.......Netflix’ kommende serie om den sorte Marvel-helt Luke Cage lander snart – midt i de aktuelle racekonflikter i USA. I GIF-anatomien "Bulletproof Black Man" sætter Henrik Højer serien ind i dens amerikanske kontekst....

  1. Black Brane World Scenarios

    CERN Document Server

    Moon, S H

    2001-01-01

    We consider a brane world residing in the interior region inside the horizon of extreme black branes. In this picture, the size of the horizon can be interpreted as the compactification size. The large mass hierarchy is simply translated into the large horizon size, which is provided by the magnitude of charges carried by the black branes. Hence, the macroscopic compactification size is a quantity calculable from the microscopic theory which has only one physical scale, and its stabilization is guaranteed from the charge conservation.

  2. Modeling black hole evaporation

    CERN Document Server

    Fabbri, Alessandro

    2005-01-01

    The scope of this book is two-fold: the first part gives a fully detailed and pedagogical presentation of the Hawking effect and its physical implications, and the second discusses the backreaction problem, especially in connection with exactly solvable semiclassical models that describe analytically the black hole evaporation process. The book aims to establish a link between the general relativistic viewpoint on black hole evaporation and the new CFT-type approaches to the subject. The detailed discussion on backreaction effects is also extremely valuable.

  3. Studies on Caffeine Content in Pu-Er Crude Tea and Pu-Er Ripe Tea%普洱生茶和熟茶中咖啡因含量测试

    Institute of Scientific and Technical Information of China (English)

    陈靖; 邹艳丽; 李聪; 王波; 谢启明

    2012-01-01

    Caffein was respectively extracted from 15 kinds of Pu-Er crude tea and 15 kinds of ripe tea by the boiling-water method.The caffein content was respectively determined by the ultraviolet spectrophotometric method,taken caffein as reference standard and the distilled water as the blank control,the absorbance of the reference and test solution was determined at 274 nm and the content of caffein was calculated by using the standard curve.The regression equation was y=47.945x+0.0015,R2=0.9999(Y and X stand for absorbance and concentration of caffein respectively),the average percentage composition of caffeine in Pu-Er crude tea was 4.29%,3.31% in Pu-Er ripe tea.The caffeine content of Pu-Er ripe tea is reduced during manufacturing process.%用热水浸提法分别提取15个普洱生茶样品和15个普洱熟茶样品中的咖啡因,采用紫外分光光度法,以咖啡因为标准品,蒸馏水为空白对照,于274 nm波长处分别测定对照品和供试品溶液的吸光度,按标准曲线计算咖啡因含量。回归方程为y=47.945x+0.0015,R2=0.9999。15个普洱生茶样品中的咖啡因平均含量4.29%,15个普洱熟茶样品中咖啡因平均含量为3.31%。

  4. Reflections on a Black Mirror

    CERN Document Server

    Good, Michael R R

    2016-01-01

    A black mirror is an accelerated boundary that produces particles in an exact correspondence to an evaporating black hole. We investigate the spectral dynamics of the particle creation during the formation process.

  5. 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.

  6. Meer bekend over Black Mold

    NARCIS (Netherlands)

    Duyvesteijn, R.G.E.; Kohrman, E.

    2008-01-01

    In de vollegrondsrozenteelt zorgde Black Mold in 2007 voor een groot aantal mislukte oculaties. In 2008 waren er aanzienlijk minder problemen. Uit onderzoek is meer bekend over de oorzaak en bestrijding van Black Mold.

  7. Black Sea Bass genetic connectivity

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Microsatellite analysis of black sea bass was undertaken to determine magnitude and direction of mixing of black seabass across the Hatteras boundary, as well as...

  8. Conquering the Black Girl Blues.

    Science.gov (United States)

    Jones, Lani Valencia; Guy-Sheftall, Beverly

    2015-10-01

    An examination of the literature on epidemiology, etiology, and use of services for this population reveals an insufficient application of culturally congruent approaches to intervening with black women. An exploration of the social work practice literature and other relevant fields indicate that black feminist perspectives offer the opportunity to gain a clearer understanding of the intersection and influence of oppression among black women struggling with psychiatric issues and provide a useful framework for mental health practice with this population. This article discusses the evolving black feminist thought and summarizes the scholarship on black women's mental health services needs and utilization issues. The article includes a discussion of black feminisms as an emerging mental health perspective, arguing that black feminist perspectives in therapy provide an ideal framework for services that are responsive to the values and health needs of black women. The article concludes with a case vignette that illustrates some of its points.

  9. 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.

  10. Black Hole: The Interior Spacetime

    CERN Document Server

    Ong, Yen Chin

    2016-01-01

    The information loss paradox is often discussed from the perspective of the observers who stay outside of a black hole. However, the interior spacetime of a black hole can be rather nontrivial. We discuss the open problems regarding the volume of a black hole, and whether it plays any role in information storage. We also emphasize the importance of resolving the black hole singularity, if one were to resolve the information loss paradox.

  11. The Black Ring is Unstable

    CERN Document Server

    Santos, Jorge E

    2015-01-01

    We study non-axisymmetric linearised gravitational perturbations of the Emparan-Reall black ring using numerical methods. We find an unstable mode whose onset lies within the "fat" branch of the black ring and continues into the "thin" branch. Together with previous results using Penrose inequalities that fat black rings are unstable, this provides numerical evidence that the entire black ring family is unstable.

  12. Remedial effect of aqueous extract of whole plant of Fumaria vaillantii Loisel and ripe fruit of Benincasa hispida Thunb in ranitidine induced-hypochlorhydric male rat

    Directory of Open Access Journals (Sweden)

    U Mandal

    2010-03-01

    Full Text Available Summary:  Prolonged uses of anti-gastric drugs such as ranitidine, omeprazole, famotidine suppress the gastric acid secretion and raise the gastric pH that creates a suitable environment for gastric infection by Helicobacter pylori. These drugs also reduce the vitamin C concentration in gastric juice and also in plasma. Standard concentration of vitamin C in gastric juice helps iron absorption and reduces the occurrence of gastric cancer. Therefore, hypochlorhydria is a risk factor of gastric carcinoma, Helicobacter pylori infection and anemia. In this study hypochlorhydria was (pH ³ 4 induced by ranitidine, a histamine receptor antagonist, and the aim of this present study is to evaluate the protective effect of pre-administration followed by co-administration of aqueous extract of whole plant of Fumaria vaillantii L. (AEFV or ripe fruit of Benincasa hispida T. (AEBH in individual as well as by composite manner in ranitidine-induced hypochlorhydric rat. We measured the pH, free acidity and total acidity, vitamin C concentration of gastric juice along with levels of vitamin C in plasma and hemoglobin in blood. These herbal extracts recovered the gastric secretion and it gave satisfactory results in vitamin C concentration in gastric juice though the composite extract is more potent than individual in this aspect. This study highlighted the protective activity of these two plants from the hypochlorhydric state. Industrial relevance: Herbal drugs are used for the treatment of different types of gastrointestinal ailments in Ayurveda. Hypochlorhydria is the common problemsof the older people due to aging and also problem of the different aged people due to unnecessary use of anti-secretory drugs. Now a day, hypochlorhydria is controlled by supplementation of betaine-HCl with pepsin, but its excess use can cause irritation in the gastric mucosa. These herbal extracts gave promising results in recovery of the hypochlorhydria without any toxic effect

  13. Health Issues Facing Black Women.

    Science.gov (United States)

    Reid, Inez Smith

    Black women in the United States experience a high incidence of serious health problems and, as a group, receive insufficient and inadequate medical care. The death rate for black women suffering from breast cancer has increased substantially since 1950. Also of great concern is the high incidence of cervical cancer in low income black women…

  14. Simulations of coalescing black holes

    CERN Document Server

    Janiuk, Agnieszka

    2016-01-01

    We describe the methods and results of numerical simulations of coalescing black holes. The simulation in dynamical spacetime covers the inspiral, merger, and ringdown phases. We analyze the emission of gravitational waves and properties of a black hole being the merger product. We discuss the results in the context of astrophysical environment of black holes that exist in the Universe.

  15. 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.

  16. "Exotic" black holes with torsion

    OpenAIRE

    2013-01-01

    In the context of three-dimensional gravity with torsion, the concepts of standard and "exotic" Banados-Teitelboim-Zanelli black holes are generalized by going over to black holes with torsion. This approach provides a unified insight into thermodynamics of black holes, with or without torsion.

  17. 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...

  18. When Black Holes Collide

    Science.gov (United States)

    Baker, John

    2010-01-01

    Among the fascinating phenomena predicted by General Relativity, Einstein's theory of gravity, black holes and gravitational waves, are particularly important in astronomy. Though once viewed as a mathematical oddity, black holes are now recognized as the central engines of many of astronomy's most energetic cataclysms. Gravitational waves, though weakly interacting with ordinary matter, may be observed with new gravitational wave telescopes, opening a new window to the universe. These observations promise a direct view of the strong gravitational dynamics involving dense, often dark objects, such as black holes. The most powerful of these events may be merger of two colliding black holes. Though dark, these mergers may briefly release more energy that all the stars in the visible universe, in gravitational waves. General relativity makes precise predictions for the gravitational-wave signatures of these events, predictions which we can now calculate with the aid of supercomputer simulations. These results provide a foundation for interpreting expect observations in the emerging field of gravitational wave astronomy.

  19. Newborn Black Holes

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Scientists using NASA's Swift satellite say they have found newborn black holes, just seconds old, in a confused state of existence. The holes are consuming material falling into them while somehow propelling other material away at great speeds. "First comes a blast of gamma rays followed by intense pulses of x-rays. The energies involved are much…

  20. Rotating regular black holes

    CERN Document Server

    Bambi, Cosimo

    2013-01-01

    The formation of spacetime singularities is a quite common phenomenon in General Relativity and it is regulated by specific theorems. It is widely believed that spacetime singularities do not exist in Nature, but that they represent a limitation of the classical theory. While we do not yet have any solid theory of quantum gravity, toy models of black hole solutions without singularities have been proposed. So far, there are only non-rotating regular black holes in the literature. These metrics can be hardly tested by astrophysical observations, as the black hole spin plays a fundamental role in any astrophysical process. In this letter, we apply the Newman-Janis algorithm to the Hayward and to the Bardeen black hole metrics. In both cases, we obtain a family of rotating solutions. Every solution corresponds to a different matter configuration. Each family has one solution with special properties, which can be written in Kerr-like form in Boyer-Lindquist coordinates. These special solutions are of Petrov type ...

  1. Celebrity-black

    DEFF Research Database (Denmark)

    Christiansen, Lene Bull; Richey, Lisa Ann

    2015-01-01

    troubled by Joof’s performances during the telethon show, which was split between performing the figure of ‘the African woman’ and Danish ‘cultural insiderness’. The article concludes that unlike the US context where the category of ‘black celebrity’ has been analysed as connecting to a particular social...

  2. Moulting Black Holes

    Science.gov (United States)

    Bena, Iosif; Chowdhury, Borun D.; de Boer, Jan; El-Showk, Sheer; Shigemori, Masaki

    2012-03-01

    We find a family of novel supersymmetric phases of the D1-D5 CFT, which in certain ranges of charges have more entropy than all known ensembles. We also find bulk BPS configurations that exist in the same range of parameters as these phases, and have more entropy than a BMPV black hole; they can be thought of as coming from a BMPV black hole shedding a "hair" condensate outside of the horizon. The entropy of the bulk configurations is smaller than that of the CFT phases, which indicates that some of the CFT states are lifted at strong coupling. Neither the bulk nor the boundary phases are captured by the elliptic genus, which makes the coincidence of the phase boundaries particularly remarkable. Our configurations are supersymmetric, have non-Cardy-like entropy, and are the first instance of a black hole entropy enigma with a controlled CFT dual. Furthermore, contrary to common lore, these objects exist in a region of parameter space (between the "cosmic censorship bound" and the "unitarity bound") where no black holes were thought to exist.

  3. Rotating regular black holes

    Energy Technology Data Exchange (ETDEWEB)

    Bambi, Cosimo, E-mail: bambi@fudan.edu.cn; Modesto, Leonardo, E-mail: lmodesto@fudan.edu.cn

    2013-04-25

    The formation of spacetime singularities is a quite common phenomenon in General Relativity and it is regulated by specific theorems. It is widely believed that spacetime singularities do not exist in Nature, but that they represent a limitation of the classical theory. While we do not yet have any solid theory of quantum gravity, toy models of black hole solutions without singularities have been proposed. So far, there are only non-rotating regular black holes in the literature. These metrics can be hardly tested by astrophysical observations, as the black hole spin plays a fundamental role in any astrophysical process. In this Letter, we apply the Newman–Janis algorithm to the Hayward and to the Bardeen black hole metrics. In both cases, we obtain a family of rotating solutions. Every solution corresponds to a different matter configuration. Each family has one solution with special properties, which can be written in Kerr-like form in Boyer–Lindquist coordinates. These special solutions are of Petrov type D, they are singularity free, but they violate the weak energy condition for a non-vanishing spin and their curvature invariants have different values at r=0 depending on the way one approaches the origin. We propose a natural prescription to have rotating solutions with a minimal violation of the weak energy condition and without the questionable property of the curvature invariants at the origin.

  4. Twistors and Black Holes

    NARCIS (Netherlands)

    Neitzke, A.; Pioline, B.; Vandoren, S.

    2007-01-01

    Motivated by black hole physics in N = 2,D = 4 supergravity, we study the geometry of quaternionic-K¨ahler manifolds Mobtained by the c-map construction from projective special Kähler manifolds Ms. Improving on earlier treatments, we compute the Käahler potentials on the twistor space Z and Swann sp

  5. Rotating black hole hair

    CERN Document Server

    Gregory, Ruth; Wills, Danielle

    2013-01-01

    A Kerr black hole sporting cosmic string hair is studied in the context of the abelian Higgs model vortex. It is shown that a such a system displays much richer phenomenology than its static Schwarzschild or Reissner--Nordstrom cousins, for example, the rotation generates a near horizon `electric' field. In the case of an extremal rotating black hole, two phases of the Higgs hair are possible: Large black holes exhibit standard hair, with the vortex piercing the event horizon. Small black holes on the other hand, exhibit a flux-expelled solution, with the gauge and scalar field remaining identically in their false vacuum state on the event horizon. This solution however is extremely sensitive to confirm numerically, and we conjecture that it is unstable due to a supperradiant mechanism similar to the Kerr-adS instability. Finally, we compute the gravitational back reaction of the vortex, which turns out to be far more nuanced than a simple conical deficit. While the string produces a conical effect, it is con...

  6. Black Strings, Black Rings and State-space Manifold

    CERN Document Server

    Bellucci, Stefano

    2011-01-01

    State-space geometry is considered, for diverse three and four parameter non-spherical horizon rotating black brane configurations, in string theory and $M$-theory. We have explicitly examined the case of unit Kaluza-Klein momentum $D_1D_5P$ black strings, circular strings, small black rings and black supertubes. An investigation of the state-space pair correlation functions shows that there exist two classes of brane statistical configurations, {\\it viz.}, the first category divulges a degenerate intrinsic equilibrium basis, while the second yields a non-degenerate, curved, intrinsic Riemannian geometry. Specifically, the solutions with finitely many branes expose that the two charged rotating $D_1D_5$ black strings and three charged rotating small black rings consort real degenerate state-space manifolds. Interestingly, arbitrary valued $M_5$-dipole charged rotating circular strings and Maldacena Strominger Witten black rings exhibit non-degenerate, positively curved, comprehensively regular state-space con...

  7. Growth of Primordial Black Holes

    Science.gov (United States)

    Harada, Tomohiro

    Primordial black holes have important observational implications through Hawking evaporation and gravitational radiation as well as being a candidate for cold dark matter. Those black holes are assumed to have formed in the early universe typically with the mass scale contained within the Hubble horizon at the formation epoch and subsequently accreted mass surrounding them. Numerical relativity simulation shows that primordial black holes of different masses do not accrete much, which contrasts with a simplistic Newtonian argument. We see that primordial black holes larger than the 'super-horizon' primordial black holes have decreasing energy and worm-hole like struture, suggesting the formation through quamtum processes.

  8. 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.

  9. 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

  10. Philosophical Issues of Black Holes

    CERN Document Server

    Romero, Gustavo E

    2014-01-01

    Black holes are extremely relativistic objects. Physical processes around them occur in a regime where the gravitational field is extremely intense. Under such conditions, our representations of space, time, gravity, and thermodynamics are pushed to their limits. In such a situation philosophical issues naturally arise. In this chapter I review some philosophical questions related to black holes. In particular, the relevance of black holes for the metaphysical dispute between presentists and eternalists, the origin of the second law of thermodynamics and its relation to black holes, the problem of information, black holes and hypercomputing, the nature of determinisim, and the breakdown of predictability in black hole space-times. I maintain that black hole physics can be used to illuminate some important problems in the border between science and philosophy, either epistemology and ontology.

  11. Bird Diversity During Ripe Berry Period of Morus Mocrora in Mountain Region,Xishuangbanna,Yunnan%长果桑果熟期摄食鸟类多样性

    Institute of Scientific and Technical Information of China (English)

    王直军; 陈进; 邓晓保; 白智林; 刘勇; 刘志秋

    2001-01-01

    A gap in current knowledge is in the ways of conver sion and recovery of mountain ecosystem, however, mobile species such as birds c an help us to know the basic dynamics of the natural processes. This work was th rough a comparative study on Morus mocroura and bird divers ity in Menglun and Nangong Mountain of Xishuangbanna to understand the dynamics. Data were analyzed using the Shannon-Wiener function formula and overlap functi on formula.   This field work was carried out during the ripe period of polymeric berries of Morus mocroura which were eaten by birds. The sizes of the fragrant polymeric berri es are suitable for different gape width that attract many species of birds, and these birds easily swallow the berries in different ways. There is a harmonious relationship between birds and food resources to coexist, however it is changin g because of the influence of human in some areas of Xishuangbanna. Through a c omparativ e study in Menglun and Nangong Mountain, concerning forest plots, the diversity( H and Hmax) of birds, and foraging ratio is higher at the Nangong Mountain, the overlap of the foraging birds and their competition is higher in Menglun forest plots. There are 35 species including 23 species and subspecies of native birds , 10 species of special protected birds have been recorded in Nangong Mountain, only 20 species including 12 species and subspecies of native birds in Menglun f orest plots. Many species of birds are quickly disappearing with the destruction of primary frest ecosystem in Menglun mountain region.   Biodiversity conservation should be put into ecosystem as a whole. If we do n ot study mountain ecosystem soon, we shall face a grave problem with a poorer en vironment and living condition. It is essential that restoration and conservatio n should be undertaken before substantial losses of species have occurred. The p roblem of bird diversity reducing should be solved by applying a system matical approach combining

  12. Optical black hole lasers

    CERN Document Server

    Faccio, Daniele; Lamperti, Marco; Leonhardt, Ulf

    2012-01-01

    Using numerical simulations we show how to realise an optical black hole laser, i.e. an amplifier formed by travelling refractive index perturbations arranged so as to trap light between a white and a black hole horizon. The simulations highlight the main features of these lasers: the growth inside the cavity of positive and negative frequency modes accompanied by a weaker emission of modes that occurs in periodic bursts corresponding to the cavity round trips of the trapped modes. We then highlight a new regime in which the trapped mode spectra broaden until the zero-frequency points on the dispersion curve are reached. Amplification at the horizon is highest for zero-frequencies, therefore leading to a strong modification of the structure of the trapped light. For sufficiently long propagation times, lasing ensues only at the zero-frequency modes.

  13. Asymmetric black dyonic holes

    Directory of Open Access Journals (Sweden)

    I. Cabrera-Munguia

    2015-04-01

    Full Text Available A 6-parametric asymptotically flat exact solution, describing a two-body system of asymmetric black dyons, is studied. The system consists of two unequal counterrotating Kerr–Newman black holes, endowed with electric and magnetic charges which are equal but opposite in sign, separated by a massless strut. The Smarr formula is generalized in order to take into account their contribution to the mass. The expressions for the horizon half-length parameters σ1 and σ2, as functions of the Komar parameters and of the coordinate distance, are displayed, and the thermodynamic properties of the two-body system are studied. Furthermore, the seven physical parameters satisfy a simple algebraic relation which can be understood as a dynamical scenario, in which the physical properties of one body are affected by the ones of the other body.

  14. Presentism meets black holes

    CERN Document Server

    Romero, Gustavo E

    2014-01-01

    Presentism is, roughly, the metaphysical doctrine that maintains that whatever exists, exists in the present. The compatibility of presentism with the theories of special and general relativity was much debated in recent years. It has been argued that at least some versions of presentism are consistent with time-orientable models of general relativity. In this paper we confront the thesis of presentism with relativistic physics, in the strong gravitational limit where black holes are formed. We conclude that the presentist position is at odds with the existence of black holes and other compact objects in the universe. A revision of the thesis is necessary, if it is intended to be consistent with the current scientific view of the universe.

  15. France in Black Africa,

    Science.gov (United States)

    1989-01-01

    mediation role between African governments and their private creditors. 123 France in Black Africa To further complicate matters, France herself is...34La coop6ration Franco-Ivoirienne, annde 1986," Mission de Cooperation et d’Action Culturelle , Ambassade de France en C6te D’Ivoire, Abidjan, 1987, p. 8...Ministry in "La France et l’Afrique: Etude des relations Franco-Africaines politiques, finan- cires, economiques, commerciales et culturelles ," Paris, 1984

  16. Black Hair is Beautiful

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    On June 9, the 1994 ⅩⅢ Asian Make-up and Hairstyling Competition was held in Beijing. More than 200 contestants from 12 countries and regions across Asia participated. The competition is now considered the largest and most prestigious exchange activity in Asian beauty and hair circles. Black Hair is Beautiful" was the theme of this competition, which stressed Asian physical characteristics and aesthetics.

  17. Black Friday = Broget Branding?

    DEFF Research Database (Denmark)

    Hansen, Heidi

    2015-01-01

    ? Essensen ved Black Friday er lave priser, og det er der ved første øjekast ikke mange brandingmuligheder forbundet ved, hvis man forstår branding som en måde at skabe ekstra værdi omkring sit produkt eller sin virksomhed. Som brand bliver man dog alligevel nødt til at forholde sig til konceptet, da det er...

  18. Life Inside Black Holes

    Science.gov (United States)

    Dokuchaev, Vyacheslav

    2013-11-01

    It is considered the test planet and photon orbits of the third kind inside the black hole (BH), which are stable, periodic and neither come out the BH nor terminate at the central singularity. Interiors of the supermassive BHs may be inhabited by advanced civilizations living on the planets with the third kind orbits. In principle, one can get information from the interiors of BHs by observing their white hole counterparts.

  19. Noncommutative Black Holes

    CERN Document Server

    Bastos, C; Dias, N C; Prata, J N

    2010-01-01

    One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity regime and it is shown that the wave function vanishes in this limit.

  20. Black Holes and Beyond

    CERN Document Server

    Mathur, Samir D

    2012-01-01

    The black hole information paradox forces us into a strange situation: we must find a way to break the semiclassical approximation in a domain where no quantum gravity effects would normally be expected. Traditional quantizations of gravity do not exhibit any such breakdown, and this forces us into a difficult corner: either we must give up quantum mechanics or we must accept the existence of troublesome `remnants'. In string theory, however, the fundamental quanta are extended objects, and it turns out that the bound states of such objects acquire a size that grows with the number of quanta in the bound state. The interior of the black hole gets completely altered to a `fuzzball' structure, and information is able to escape in radiation from the hole. The semiclassical approximation can break at macroscopic scales due to the large entropy of the hole: the measure in the path integral competes with the classical action, instead of giving a subleading correction. Putting this picture of black hole microstates ...

  1. Slowly balding black holes

    CERN Document Server

    Lyutikov, Maxim

    2011-01-01

    The "no hair" theorem, a key result in General Relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the "no hair" theorem is not formally applicable for black holes formed from collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively "frozen-in" the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes $N_B = e \\Phi_\\infty /(\\pi c \\hbar)$, where $\\Phi_\\infty \\approx 2 \\pi^2 B_{NS} R_{NS}^3 /(P_{\\rm NS} c)$ is the initial magnetic flux through the hemisphere...

  2. Linear dilaton black holes

    CERN Document Server

    Clément, G; Leygnac, C; Clement, Gerard; Gal'tsov, Dmitri; Leygnac, Cedric

    2003-01-01

    We present new solutions to Einstein-Maxwell-dilaton-axion (EMDA) gravity in four dimensions describing black holes which asymptote to the linear dilaton background. In the non-rotating case they can be obtained as the limiting geometry of dilaton black holes. The rotating solutions (possibly endowed with a NUT parameter) are constructed using a generating technique based on the Sp(4,R) duality of the EMDA system. In a certain limit (with no event horizon present) our rotating solutions coincide with supersymmetric Israel-Wilson-Perjes type dilaton-axion solutions. In presence of an event horizon supersymmetry is broken. The temperature of the static black holes is constant, and their mass does not depend on it, so the heat capacity is zero. We investigate geodesics and wave propagation in these spacetimes and find superradiance in the rotating case. Because of the non-asymptotically flat nature of the geometry, certain modes are reflected from infinity, in particular, all superradiant modes are confined. Thi...

  3. Moulting Black Holes

    CERN Document Server

    Bena, Iosif; de Boer, Jan; El-Showk, Sheer; Shigemori, Masaki

    2011-01-01

    We find a family of novel supersymmetric phases of the D1-D5 CFT, which in certain ranges of charges have more entropy than all known ensembles. We also find bulk BPS configurations that exist in the same range of parameters as these phases, and have more entropy than a BMPV black hole; they can be thought of as coming from a BMPV black hole shedding a "hair" condensate outside of the horizon. The entropy of the bulk configurations is smaller than that of the CFT phases, which indicates that some of the CFT states are lifted at strong coupling. Neither the bulk nor the boundary phases are captured by the elliptic genus, which makes the coincidence of the phase boundaries particularly remarkable. Our configurations are supersymmetric, have non-Cardy-like entropy, and are the first instance of a black hole entropy enigma with a controlled CFT dual. Furthermore, contrary to common lore, these objects exist in a region of parameter space (between the "cosmic censorship bound" and the "unitarity bound") where no b...

  4. Attractors in Black

    CERN Document Server

    Bellucci, S; Marrani, A

    2008-01-01

    We review recent results in the study of attractor horizon geometries (with non-vanishing Bekenstein-Hawking entropy) of dyonic extremal d=4 black holes in supergravity. We focus on N=2, d=4 ungauged supergravity coupled to a number n_{V} of Abelian vector multiplets, outlining the fundamentals of the special Kaehler geometry of the vector multiplets' scalar manifold (of complex dimension n_{V}), and studying the 1/2-BPS attractors, as well as the non-BPS (non-supersymmetric) ones with non-vanishing central charge. For symmetric special Kaehler geometries, we present the complete classification of the orbits in the symplectic representation of the classical U-duality group (spanned by the black hole charge configuration supporting the attractors), as well as of the moduli spaces of non-BPS attractors (spanned by the scalars which are not stabilized at the black hole event horizon). Finally, we report on an analogous classification for N>2-extended, d=4 ungauged supergravities, in which also the 1/N-BPS attrac...

  5. Non-Abelian magnetic black strings versus black holes

    Science.gov (United States)

    Mazharimousavi, S. Habib; Halilsoy, M.

    2016-05-01

    We present d+1 -dimensional pure magnetic Yang-Mills (YM) black strings (or 1-branes) induced by the d -dimensional Einstein-Yang-Mills-Dilaton black holes. The Born-Infeld version of the YM field makes our starting point which goes to the standard YM field through a limiting procedure. The lifting from black holes to black strings (with less number of fields) is done by adding an extra, compact coordinate. This amounts to the change of horizon topology from S^{d-2} to a product structure. Our black string in 5 dimensions is a rather special one, with uniform Hawking temperature and non-asymptotically flat structure. As the YM charge becomes large the string gets thinner to tend into a breaking point and transform into a 4-dimensional black hole.

  6. 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....

  7. Black Holes with Skyrme Hair

    CERN Document Server

    Shiiki, N; Shiiki, Noriko; Sawado, Nobuyuki

    2005-01-01

    This paper is intended to give a review of the recent developments on black holes with Skyrme hair. The Einstein-Skyrme system is known to possess black hole solutions with Skyrme hair. The spherically symmetric black hole skyrmion with B=1 was the first discovered counter example of the no-hair conjecture for black holes. Recently we found the B=2 axially symmetric black hole skyrmion. In this system, the black hole at the center of the skyrmion absorbs the baryon number partially, leaving fractional charge outside the horizon. Therefore the baryon number is no longer conserved. We examine the B=1, 2 black hole solutions in detail in this paper. The model has a natural extension to the gauged version which can describe monopole black hole skyrmions. Callan and Witten discussed the monopole catalysis of proton decay within the Skyrme model. We apply the idea to the Einstein-Maxwell-Skyrme system and obtain monopole black hole skyrmions. Remarkably there exist multi-black hole skyrmion solutions in which the g...

  8. How Black Are Black Hole Candidates?

    CERN Document Server

    Robertson, S L; Robertson, Stanley L.; Leiter, Darryl J.

    2002-01-01

    In previous work we found that many of the spectral properties of x-ray binaries, including both galactic black hole candiates (GBHC) and neutron stars, were consistent with the existence of intrinsically magnetized central objects. Here we review and extend the observational evidence for the existence of intrinsically magnetized GBHC and show that their existence is consistent with a new class of solutions of the Einstein field equations of General Relativity. These solutions are based on a strict adherence to the Principle of Equivalence, which prevents the time-like geodesics of physical matter from becoming null on trapped surfaces of infinite red shift. The new solutions emerge from the fact that the structure and radiation transfer properties of the energy-momentum tensor on the right hand side of the Einstein field equations must have a form that is consistent with this Principle of Equivalence requirement. In this context, we show that the Einstein field equations allow the existence of highly red shi...

  9. Black Swan Tropical Cyclones

    Science.gov (United States)

    Emanuel, K.; Lin, N.

    2012-12-01

    Virtually all assessments of tropical cyclone risk are based on historical records, which are limited to a few hundred years at most. Yet stronger TCs may occur in the future and at places that have not been affected historically. Such events lie outside the realm of historically based expectations and may have extreme impacts. Their occurrences are also often made explainable after the fact (e.g., Hurricane Katrina). We nickname such potential future TCs, characterized by rarity, extreme impact, and retrospective predictability, "black swans" (Nassim Nicholas Taleb, 2007). As, by definition, black swan TCs have yet to happen, statistical methods that solely rely on historical track data cannot predict their occurrence. Global climate models lack the capability to predict intense storms, even with a resolution as high as 14 km (Emanuel et al. 2010). Also, most dynamic downscaling methods (e.g., Bender et al. 2010) are still limited in horizontal resolution and are too expensive to implement to generate enough events to include rare ones. In this study, we apply a simpler statistical/deterministic hurricane model (Emanuel et al. 2006) to simulate large numbers of synthetic storms under a given (observed or projected) climate condition. The method has been shown to generate realistic extremes in various basins (Emanuel et al. 2008 and 2010). We also apply a hydrodynamic model (ADCIRC; Luettich et al. 1992) to simulate the storm surges generated by these storms. We then search for black swan TCs, in terms of the joint wind and surge damage potential, in the generated large databases. Heavy rainfall is another important TC hazard and will be considered in a future study. We focus on three areas: Tampa Bay in the U.S., the Persian Gulf, and Darwin in Australia. Tampa Bay is highly vulnerable to storm surge as it is surrounded by shallow water and low-lying lands, much of which may be inundated by a storm tide of 6 m. High surges are generated by storms with a broad

  10. Geometry of black hole spacetimes

    CERN Document Server

    Andersson, Lars; Blue, Pieter

    2016-01-01

    These notes, based on lectures given at the summer school on Asymptotic Analysis in General Relativity, collect material on the Einstein equations, the geometry of black hole spacetimes, and the analysis of fields on black hole backgrounds. The Kerr model of a rotating black hole in vacuum is expected to be unique and stable. The problem of proving these fundamental facts provides the background for the material presented in these notes. Among the many topics which are relevant for the uniqueness and stability problems are the theory of fields on black hole spacetimes, in particular for gravitational perturbations of the Kerr black hole, and more generally, the study of nonlinear field equations in the presence of trapping. The study of these questions requires tools from several different fields, including Lorentzian geometry, hyperbolic differential equations and spin geometry, which are all relevant to the black hole stability problem.

  11. Sarcoid granuloma on black tattoo.

    Science.gov (United States)

    Morales-Callaghan, Ana María; Aguilar-Bernier, Miguel; Martínez-García, Gerardo; Miranda-Romero, Alberto

    2006-11-01

    We report the case of a patient with a black and turquoise tattoo who developed sarcoid granulomas on the areas of black pigment. Patch tests showed a positive reaction to nickel, cobalt, and cadmium; spectrophotometric analysis of the black pigment revealed the presence of nickel and cobalt among other metals. Although the pathogenesis of sarcoid granulomas is unknown, it seems that a delayed type hypersensitivity reaction is one of the mechanisms involved.

  12. Origin of supermassive black holes

    OpenAIRE

    Dokuchaev, V. I.; Eroshenko, Yu. N.; Rubin, S G

    2007-01-01

    The origin of supermassive black holes in the galactic nuclei is quite uncertain in spite of extensive set of observational data. We review the known scenarios of galactic and cosmological formation of supermassive black holes. The common drawback of galactic scenarios is a lack of time and shortage of matter supply for building the supermassive black holes in all galaxies by means of accretion and merging. The cosmological scenarios are only fragmentarily developed but propose and pretend to...

  13. The Gifted Black Child: Problems and Promise.

    Science.gov (United States)

    Howard, John R.

    In this paper, it is noted that there are three reasons for studying the black gifted child. First, black destiny has in part been shaped by talented blacks--for example, Malcolm X and Martin Luther King. Second, the black gifted are a minority within a minority. The gifted black female, subject to sexism, is even more of a minority. Third,…

  14. Thermodynamics of Accelerating Black Holes.

    Science.gov (United States)

    Appels, Michael; Gregory, Ruth; Kubizňák, David

    2016-09-23

    We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon-even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.

  15. Black holes and the multiverse

    Science.gov (United States)

    Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun

    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.

  16. How black holes saved relativity

    Science.gov (United States)

    Prescod-Weinstein, Chanda

    2016-02-01

    While there have been many popular-science books on the historical and scientific legacy of Albert Einstein's general theory of relativity, a gap exists in the literature for a definitive, accessible history of the theory's most famous offshoot: black holes. In Black Hole, the science writer Marcia Bartusiak aims for a discursive middle ground, writing solely about black holes at a level suitable for both high-school students and more mature readers while also giving some broader scientific context for black-hole research.

  17. Black monazite from Taiwan

    Science.gov (United States)

    Matzko, J.J.; Overstreet, W.C.

    1977-01-01

    Two forms of detrital monazite are known in offshore bars in southwestern Taiwan: a yellow-green to colorless form and an unusual but abundant pelletlike form, generally black but also colored gray or brown. These black pellets, which are about 160 by 200 microns in size, are composed of fine-grained monazite crystals from 2 to 20 microns in size. The pellets are associated with highly variable amounts of discrete grains of detrital quartz, rutile, amphibole, tourmaline, and other minerals. Intergrown with the monazite are quartz, a cerium oxide mineral, chlorite, sulfides, and other minerals. Opaqueness of the pelletlike monazite is due principally to the cryptocrystalline nature of part of the monazite; only a small part of the opaqueness can be attributed to opaque inclusions. The black pelletlike monazite lacks thorium and has a high content of europium. In this respect, as in color, shape, size, and inclusions, the pelletlike monazite differs from the yellow-green detrital monazite. Despite the fact that they occur together in the littoral placers, they appear to have had different origins. The yellow-green monazite originated as an accessory mineral in plutonic rocks and has accumulated at the coast through erosion and transport. The origin of the pelletlike monazite is as yet unknown, but it is here inferred that it originated in unconsolidated coastal plain sediments through migration of cerium from the detrital monazite during weathering, and of the intermediate weight mobile rare earths from clay minerals during diagenesis. Possibly these pelletlike grains are detrital particles formed through erosion and transport from originally larger aggregates cemented by diagenetic monazite.

  18. Magnonic Black Holes.

    Science.gov (United States)

    Roldán-Molina, A; Nunez, Alvaro S; Duine, R A

    2017-02-10

    We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons-the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

  19. Thermal BEC Black Holes

    Directory of Open Access Journals (Sweden)

    Roberto Casadio

    2015-10-01

    Full Text Available We review some features of Bose–Einstein condensate (BEC models of black holes obtained by means of the horizon wave function formalism. We consider the Klein–Gordon equation for a toy graviton field coupled to a static matter current in a spherically-symmetric setup. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with a continuous occupation number. An attractive self-interaction is needed for bound states to form, the case in which one finds that (approximately one mode is allowed, and the system of N bosons can be self-confined in a volume of the size of the Schwarzschild radius. The horizon wave function formalism is then used to show that the radius of such a system corresponds to a proper horizon. The uncertainty in the size of the horizon is related to the typical energy of Hawking modes: it decreases with the increasing of the black hole mass (larger number of gravitons, resulting in agreement with the semiclassical calculations and which does not hold for a single very massive particle. The spectrum of these systems has two components: a discrete ground state of energy m (the bosons forming the black hole and a continuous spectrum with energy ω > m (representing the Hawking radiation and modeled with a Planckian distribution at the expected Hawking temperature. Assuming the main effect of the internal scatterings is the Hawking radiation, the N-particle state can be collectively described by a single-particle wave-function given by a superposition of a total ground state with energy M = Nm and Entropy 2015, 17 6894 a Planckian distribution for E > M at the same Hawking temperature. This can be used to compute the partition function and to find the usual area law for the entropy, with a logarithmic correction related to the Hawking component. The backreaction of modes with ω > m is also shown to reduce

  20. Noncommutative black holes

    Energy Technology Data Exchange (ETDEWEB)

    Bastos, C; Bertolami, O [Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Dias, N C; Prata, J N, E-mail: cbastos@fisica.ist.utl.p, E-mail: orfeu@cosmos.ist.utl.p, E-mail: ncdias@mail.telepac.p, E-mail: joao.prata@mail.telepac.p [Departamento de Matematica, Universidade Lusofona de Humanidades e Tecnologias, Avenida Campo Grande, 376, 1749-024 Lisboa (Portugal)

    2010-04-01

    One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity parameter, {eta}. Furthermore, the t = r = 0 singularity is analysed in the noncommutative regime and it is shown that the wave function vanishes in this limit.

  1. Black hole accretion discs

    OpenAIRE

    Lasota, Jean-Pierre

    2015-01-01

    This is an introduction to models of accretion discs around black holes. After a presentation of the non-relativistic equations describing the structure and evolution of geometrically thin accretion discs we discuss their steady-state solutions and compare them to observation. Next we describe in detail the thermal-viscous disc instability model and its application to dwarf novae for which it was designed and its X-ray irradiated-disc version which explains the soft X--ray transients, i.e. ou...

  2. Magnonic Black Holes

    Science.gov (United States)

    Roldán-Molina, A.; Nunez, Alvaro S.; Duine, R. A.

    2017-02-01

    We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons—the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

  3. Artificial black holes

    CERN Document Server

    Visser, Matt; Volovik, Grigory E

    2009-01-01

    Physicists are pondering on the possibility of simulating black holes in the laboratory by means of various "analog models". These analog models, typically based on condensed matter physics, can be used to help us understand general relativity (Einstein's gravity); conversely, abstract techniques developed in general relativity can sometimes be used to help us understand certain aspects of condensed matter physics. This book contains 13 chapters - written by experts in general relativity, particle physics, and condensed matter physics - that explore various aspects of this two-way traffic.

  4. 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)

  5. Black German identities : validating the multidimensional inventory of black identity

    NARCIS (Netherlands)

    Wandert, T.; Ochsmann, R.; Brug, P.; Chybicka, A.; Lacassagne, M.F.; Verkuyten, M.J.A.M.

    2009-01-01

    This study examines the reliability and validity of a German version of the Multidimensional Inventory of Black Identity (MIBI) in a sample of 170 Black Germans. The internal consistencies of all subscales are at least moderate. The factorial structure of the MIBI, as assessed by principal component

  6. Growing Up Black: A Black Literature Unit For Schools

    Science.gov (United States)

    Massenburg, Doris O.; Applebury, Bruce C.

    1971-01-01

    This literature-based unit is intended to examine the prevalent black moods, conflicts, alienations and disillusionments which accompany the present era. Literature selections include works by both black and white writers. At the end of the unit, the student will be able to realize the man, from what literature has stamped as substantial accounts…

  7. Surfing a Black Hole

    Science.gov (United States)

    2002-10-01

    Star Orbiting Massive Milky Way Centre Approaches to within 17 Light-Hours [1] Summary An international team of astronomers [2], lead by researchers at the Max-Planck Institute for Extraterrestrial Physics (MPE) , has directly observed an otherwise normal star orbiting the supermassive black hole at the center of the Milky Way Galaxy. Ten years of painstaking measurements have been crowned by a series of unique images obtained by the Adaptive Optics (AO) NAOS-CONICA (NACO) instrument [3] on the 8.2-m VLT YEPUN telescope at the ESO Paranal Observatory. It turns out that earlier this year the star approached the central Black Hole to within 17 light-hours - only three times the distance between the Sun and planet Pluto - while travelling at no less than 5000 km/sec . Previous measurements of the velocities of stars near the center of the Milky Way and variable X-ray emission from this area have provided the strongest evidence so far of the existence of a central Black Hole in our home galaxy and, implicitly, that the dark mass concentrations seen in many nuclei of other galaxies probably are also supermassive black holes. However, it has not yet been possible to exclude several alternative configurations. In a break-through paper appearing in the research journal Nature on October 17th, 2002, the present team reports their exciting results, including high-resolution images that allow tracing two-thirds of the orbit of a star designated "S2" . It is currently the closest observable star to the compact radio source and massive black hole candidate "SgrA*" ("Sagittarius A") at the very center of the Milky Way. The orbital period is just over 15 years. The new measurements exclude with high confidence that the central dark mass consists of a cluster of unusual stars or elementary particles, and leave little doubt of the presence of a supermassive black hole at the centre of the galaxy in which we live . PR Photo 23a/02 : NACO image of the central region of the Milky Way

  8. Astrophysical Black Holes in the Physical Universe

    CERN Document Server

    Zhang, Shuang-Nan

    2010-01-01

    In this chapter I focus on asking and answering the following questions: (1) What is a black hole? Answer: There are three types of black holes, namely mathematical black holes, physical black holes and astrophysical black holes. An astrophysical black hole, with mass distributed within its event horizon but not concentrated at the singularity point, is not a mathematical black hole. (2) Can astrophysical black holes be formed in the physical universe? Answer: Yes, at least this can be done with gravitational collapse. (3) How can we prove that what we call astrophysical black holes are really black holes? Answer: Finding direct evidence of event horizon is not the way to go. Instead I propose five criteria which meet the highest standard for recognizing new discoveries in experimental physics and observational astronomy. (4) Do we have sufficient evidence to claim the existence of astrophysical black holes in the physical universe? Answer: Yes, astrophysical black holes have been found at least in some galac...

  9. Area spectrum of slowly rotating black holes

    OpenAIRE

    2010-01-01

    We investigate the area spectrum for rotating black holes which are Kerr and BTZ black holes. For slowly rotating black holes, we use the Maggiore's idea combined with Kunstatter's method to derive their area spectra, which are equally spaced.

  10. Black holes in an expanding universe.

    Science.gov (United States)

    Gibbons, Gary W; Maeda, Kei-ichi

    2010-04-02

    An exact solution representing black holes in an expanding universe is found. The black holes are maximally charged and the universe is expanding with arbitrary equation of state (P = w rho with -1 black hole temperature.

  11. Twistors and Black Holes

    CERN Document Server

    Neitzke, A; Vandoren, S; Neitzke, Andrew; Pioline, Boris; Vandoren, Stefan

    2007-01-01

    Motivated by black hole physics in N=2, D=4 supergravity, we study the geometry of quaternionic-Kahler manifolds M obtained by the c-map construction from projective special Kahler manifolds M_s. Improving on earlier treatments, we compute the Kahler potentials on the twistor space Z and Swann space S in the complex coordinates adapted to the Heisenberg symmetries. The results bear a simple relation to the Hesse potential \\Sigma of the special Kahler manifold M_s, and hence to the Bekenstein-Hawking entropy for BPS black holes. We explicitly construct the ``covariant c-map'' and the ``twistor map'', which relate real coordinates on M x CP^1 (resp. M x R^4/Z_2) to complex coordinates on Z (resp. S). As applications, we solve for the general BPS geodesic motion on M, and provide explicit integral formulae for the quaternionic Penrose transform relating elements of H^1(Z,O(-k)) to massless fields on M annihilated by first or second order differential operators. Finally, we compute the exact radial wave function ...

  12. Transient Black Hole Binaries

    CERN Document Server

    Belloni, T M

    2016-01-01

    The last two decades have seen a great improvement in our understand- ing of the complex phenomenology observed in transient black-hole binary systems, especially thanks to the activity of the Rossi X-Ray Timing Explorer satellite, com- plemented by observations from many other X-ray observatories and ground-based radio, optical and infrared facilities. Accretion alone cannot describe accurately the intricate behavior associated with black-hole transients and it is now clear that the role played by different kinds of (often massive) outflows seen at different phases of the outburst evolution of these systems is as fundamental as the one played by the accretion process itself. The spectral-timing states originally identified in the X-rays and fundamentally based on the observed effect of accretion, have acquired new importance as they now allow to describe within a coherent picture the phenomenology observed at other wave- length, where the effects of ejection processes are most evident. With a particular focu...

  13. Black hairy tongue syndrome.

    Science.gov (United States)

    Gurvits, Grigoriy E; Tan, Amy

    2014-08-21

    Black hairy tongue (BHT) is a benign medical condition characterized by elongated filiform lingual papillae with typical carpet-like appearance of the dorsum of the tongue. Its prevalence varies geographically, typically ranging from 0.6% to 11.3%. Known predisposing factors include smoking, excessive coffee/black tea consumption, poor oral hygiene, trigeminal neuralgia, general debilitation, xerostomia, and medication use. Clinical presentation varies but is typically asymptomatic, although aesthetic concerns are common. Differential diagnosis includes pseudo-BHT, acanthosis nigricans, oral hairy leukoplakia, pigmented fungiform papillae of the tongue, and congenital melanocytic/melanotic nevi/macules. Clinical diagnosis relies on visual observation, detailed history taking, and occasionally microscopic evaluation. Treatment involves identification and discontinuation of the offending agent, modifications of chronic predisposing factors, patient's re-assurance to the benign nature of the condition, and maintenance of adequate oral hygiene with gentle debridement to promote desquamation. Complications of BHT (burning mouth syndrome, halitosis, nausea, gagging, dysgeusia) typically respond to therapy. Prognosis is excellent with treatment of underlying medical conditions. BHT remains an important medical condition which may result in additional burden on the patient and health care system and requires appropriate prevention, recognition and treatment.

  14. Black raspberry: Korean vs. American

    Science.gov (United States)

    This fact sheet shows Korean black raspberry (Rubus coreanus) fruit, flower, and leaf features that distinguish them from their Rubus relatives, black raspberry (R. occidentalis) native to America. Common names with fruit characteristics, including berry size and pigment fingerprints, are summarized...

  15. Black Component of Dark Matter

    Directory of Open Access Journals (Sweden)

    A. V. Grobov

    2014-01-01

    Full Text Available A mechanism of primordial black hole formation with specific mass spectrum is discussed. It is shown that these black holes could contribute to the energy density of dark matter. Our approach is elaborated in the framework of universal extra dimensions.

  16. Black holes in brane worlds

    Indian Academy of Sciences (India)

    M S Modgil; S Panda; S Sengupta

    2004-03-01

    A Kerr metric describing a rotating black hole is obtained on the three brane in a five-dimensional Randall-Sundrum brane world by considering a rotating five-dimensional black string in the bulk. We examine the causal structure of this space-time through the geodesic equations.

  17. Educating Black Males with Dyslexia

    Science.gov (United States)

    Robinson, Shawn Anthony

    2013-01-01

    Much of the scholarship on Black males in the educational literature focuses on the achievement gap; their underrepresentation in gifted and advanced placement programs; their overrepresentation in special education programs and their high rates of school suspensions and expulsions. Although overrepresented in special education, Black males with…

  18. Black-Hole Mass Measurements

    DEFF Research Database (Denmark)

    Vestergaard, Marianne

    2004-01-01

    The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized.......The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized....

  19. ATLAS simulated black hole event

    CERN Multimedia

    Pequenão, J

    2008-01-01

    The simulated collision event shown is viewed along the beampipe. The event is one in which a microscopic-black-hole was produced in the collision of two protons (not shown). The microscopic-black-hole decayed immediately into many particles. The colors of the tracks show different types of particles emerging from the collision (at the center).

  20. Nonlinear Electrodynamics and black holes

    CERN Document Server

    Breton, N; Breton, Nora; Garcia-Salcedo, Ricardo

    2007-01-01

    It is addressed the issue of black holes with nonlinear electromagnetic field, focussing mainly in the Born-Infeld case. The main features of these systems are described, for instance, geodesics, energy conditions, thermodynamics and isolated horizon aspects. Also are revised some black hole solutions of alternative nonlinear electrodynamics and its inconveniences.

  1. When Charged Black Holes Merge

    Science.gov (United States)

    Kohler, Susanna

    2016-08-01

    Most theoretical models assume that black holes arent charged. But a new study shows that mergers of charged black holes could explain a variety of astrophysical phenomena, from fast radio bursts to gamma-ray bursts.No HairThe black hole no hair theorem states that all black holes can be described by just three things: their mass, their spin, and their charge. Masses and spins have been observed and measured, but weve never measured the charge of a black hole and its widely believed that real black holes dont actually have any charge.That said, weve also never shown that black holes dont have charge, or set any upper limits on the charge that they might have. So lets suppose, for a moment, that its possible for a black hole to be charged. How might that affect what we know about the merger of two black holes? A recent theoretical study by Bing Zhang (University of Nevada, Las Vegas) examines this question.Intensity profile of a fast radio burst, a sudden burst of radio emission that lasts only a few milliseconds. [Swinburne Astronomy Productions]Driving TransientsZhangs work envisions a pair of black holes in a binary system. He argues that if just one of the black holes carries charge possibly retained by a rotating magnetosphere then it may be possible for the system to produce an electromagnetic signal that could accompany gravitational waves, such as a fast radio burst or a gamma-ray burst!In Zhangs model, the inspiral of the two black holes generates a global magnetic dipole thats perpendicular to the plane of the binarys orbit. The magnetic flux increases rapidly as the separation between the black holes decreases, generating an increasingly powerful magnetic wind. This wind, in turn, can give rise to a fast radio burst or a gamma-ray burst, depending on the value of the black holes charge.Artists illustration of a short gamma-ray burst, thought to be caused by the merger of two compact objects. [ESO/A. Roquette]Zhang calculates lower limits on the charge

  2. Black holes and the multiverse

    CERN Document Server

    Garriga, Jaume; Zhang, Jun

    2015-01-01

    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 blac...

  3. String-Corrected Black Holes

    Energy Technology Data Exchange (ETDEWEB)

    Hubeny, Veronika; Maloney, Alexander; Rangamani, Mukund

    2005-02-07

    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.

  4. Genetic Diversity and Population Differentiation of the Causal Agent of Citrus Black Spot in Brazil

    Directory of Open Access Journals (Sweden)

    Ester Wickert

    2012-01-01

    Full Text Available One of the most important diseases that affect sweet orange orchards in Brazil is the Citrus Black Spot that is caused by the fungus Guignardia citricarpa. This disease causes irreparable losses due to the premature falling of fruit, as well as its severe effects on the epidermis of ripe fruit that renders them unacceptable at the fresh fruit markets. Despite the fact that the fungus and the disease are well studied, little is known about the genetic diversity and the structure of the fungi populations in Brazilian orchards. The objective of this work was study the genetic diversity and population differentiation of G. citricarpa associated with four sweet orange varieties in two geographic locations using DNA sequence of ITS1-5.8S-ITS2 region from fungi isolates. We observed that different populations are closely related and present little genetic structure according to varieties and geographic places with the highest genetic diversity distributed among isolates of the same populations. The same haplotypes were sampled in different populations from the same and different orange varieties and from similar and different origins. If new and pathogenic fungi would become resistant to fungicides, the observed genetic structure could rapidly spread this new form from one population to others.

  5. 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…

  6. Magnetic fields around black holes

    Science.gov (United States)

    Garofalo, David A. G.

    Active Galactic Nuclei are the most powerful long-lived objects in the universe. They are thought to harbor supermassive black holes that range from 1 million solar masses to 1000 times that value and possibly greater. Theory and observation are converging on a model for these objects that involves the conversion of gravitational potential energy of accreting gas to radiation as well as Poynting flux produced by the interaction of the rotating spacetime and the electromagnetic fields originating in the ionized accretion flow. The presence of black holes in astrophysics is taking center stage, with the output from AGN in various forms such as winds and jets influencing the formation and evolution of the host galaxy. This dissertation addresses some of the basic unanswered questions that plague our current understanding of how rotating black holes interact with their surrounding magnetized accretion disks to produce the enormous observed energy. Two magnetic configurations are examined. The first involves magnetic fields connecting the black hole with the inner accretion disk and the other involves large scale magnetic fields threading the disk and the hole. We study the effects of the former type by establishing the consequences that magnetic torques between the black hole and the inner accretion disk have on the energy dissipation profile. We attempt a plausible explanation to the observed "Deep Minimum" state in the Seyfert galaxy MCG-6- 30-15. For the latter type of magnetic geometry, we study the effects of the strength of the magnetic field threading the black hole within the context of the cherished Blandford & Znajek mechanism for black hole spin energy extraction. We begin by addressing the problem in the non-relativistic regime where we find that the black hole-threading magnetic field is stronger for greater disk thickness, larger magnetic Prandtl number, and for a larger accretion disk. We then study the problem in full relativity where we show that our

  7. The renaissance of black phosphorus

    Science.gov (United States)

    Ling, Xi; Wang, Han; Huang, Shengxi; Xia, Fengnian; Dresselhaus, Mildred S.

    2015-04-01

    One hundred years after its first successful synthesis in the bulk form in 1914, black phosphorus (black P) was recently rediscovered from the perspective of a 2D layered material, attracting tremendous interest from condensed matter physicists, chemists, semiconductor device engineers, and material scientists. Similar to graphite and transition metal dichalcogenides (TMDs), black P has a layered structure but with a unique puckered single-layer geometry. Because the direct electronic band gap of thin film black P can be varied from 0.3 eV to around 2 eV, depending on its film thickness, and because of its high carrier mobility and anisotropic in-plane properties, black P is promising for novel applications in nanoelectronics and nanophotonics different from graphene and TMDs. Black P as a nanomaterial has already attracted much attention from researchers within the past year. Here, we offer our opinions on this emerging material with the goal of motivating and inspiring fellow researchers in the 2D materials community and the broad readership of PNAS to discuss and contribute to this exciting new field. We also give our perspectives on future 2D and thin film black P research directions, aiming to assist researchers coming from a variety of disciplines who are desirous of working in this exciting research field.

  8. A nonsingular rotating black hole

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, Durban (South Africa)

    2015-11-15

    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.)

  9. Rotating black hole and quintessence

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, Private Bag 54001, Durban (South Africa)

    2016-04-15

    We discuss spherically symmetric exact solutions of the Einstein equations for quintessential matter surrounding a black hole, which has an additional parameter (ω) due to the quintessential matter, apart from the mass (M). In turn, we employ the Newman-Janis complex transformation to this spherical quintessence black hole solution and present a rotating counterpart that is identified, for α = -e{sup 2} ≠ 0 and ω = 1/3, exactly as the Kerr-Newman black hole, and as the Kerr black hole when α = 0. Interestingly, for a given value of parameter ω, there exists a critical rotation parameter (a = a{sub E}), which corresponds to an extremal black hole with degenerate horizons, while for a < a{sub E}, it describes a nonextremal black hole with Cauchy and event horizons, and no black hole for a > a{sub E}. We find that the extremal value a{sub E} is also influenced by the parameter ω and so is the ergoregion. (orig.)

  10. 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)

  11. Cosmic Intelligence and Black Holes

    CERN Document Server

    Lefebvre, V A; Lefebvre, Vladimir A.; Efremov, Yuri N.

    2000-01-01

    The paper is devoted to a new direction in SETI. After a general discussion of the field, the authors put forth the hypothesis that the black holes may serve as a physical substratum for intelligent beings. This hypothesis is based on four parallels between the brain-psyche system, on the one hand, and black holes, on the other. (1) The descriptions of brain and psyche, in the system brain-psyche, are complementary to each other, as descriptions by internal and external observers of a black hole in Susskind-t'Hooft's schema. (2) There is an aspect of the inner structure of a black hole in Kerr's model of the rotating black hole that is isomorphic to the structure of the human subjective domain in the psychological model of reflexion. (3) Both black holes and the brain-psyche system have a facet which can be represented using thermodynamic concepts. (4) The brain lends itself to a holographic description; as has been recently demonstrated by Susskind, black holes can also be described holographically. The auth...

  12. 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

    ... Energy Regulatory Commission Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of Application for Partial Transfer of Licenses, and Soliciting Comments and Motions To Intervene On October 25, 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor)...

  13. Can Black Hole Relax Unitarily?

    Science.gov (United States)

    Solodukhin, S. N.

    2005-03-01

    We review the way the BTZ black hole relaxes back to thermal equilibrium after a small perturbation and how it is seen in the boundary (finite volume) CFT. The unitarity requires the relaxation to be quasi-periodic. It is preserved in the CFT but is not obvious in the case of the semiclassical black hole the relaxation of which is driven by complex quasi-normal modes. We discuss two ways of modifying the semiclassical black hole geometry to maintain unitarity: the (fractal) brick wall and the worm-hole modification. In the latter case the entropy comes out correctly as well.

  14. Quantum mechanics of black holes.

    Science.gov (United States)

    Witten, Edward

    2012-08-03

    The popular conception of black holes reflects the behavior of the massive black holes found by astronomers and described by classical general relativity. These objects swallow up whatever comes near and emit nothing. Physicists who have tried to understand the behavior of black holes from a quantum mechanical point of view, however, have arrived at quite a different picture. The difference is analogous to the difference between thermodynamics and statistical mechanics. The thermodynamic description is a good approximation for a macroscopic system, but statistical mechanics describes what one will see if one looks more closely.

  15. Orbital resonances around black holes.

    Science.gov (United States)

    Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja

    2015-02-27

    We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.

  16. Black holes and Higgs stability

    Energy Technology Data Exchange (ETDEWEB)

    Tetradis, Nikolaos [Department of Physics, University of Athens,Zographou 157 84 (Greece); Physics Department, Theory Unit, CERN,CH-1211 Geneva 23 (Switzerland)

    2016-09-20

    We study the effect of primordial black holes on the classical rate of nucleation of AdS regions within the standard electroweak vacuum. We find that the energy barrier for transitions to the new vacuum, which characterizes the exponential suppression of the nucleation rate, can be reduced significantly in the black-hole background. A precise analysis is required in order to determine whether the the existence of primordial black holes is compatible with the form of the Higgs potential at high temperature or density in the Standard Model or its extensions.

  17. The Black Hole Information Problem

    CERN Document Server

    Polchinski, Joseph

    2016-01-01

    The black hole information problem has been a challenge since Hawking's original 1975 paper. It led to the discovery of AdS/CFT, which gave a partial resolution of the paradox. However, recent developments, in particular the firewall puzzle, show that there is much that we do not understand. I review the black hole, Hawking radiation, and the Page curve, and the classic form of the paradox. I discuss AdS/CFT as a partial resolution. I then discuss black hole complementarity and its limitations, leading to many proposals for different kinds of `drama.' I conclude with some recent ideas.

  18. Static-Fluid Black Holes

    CERN Document Server

    Cho, Inyong

    2016-01-01

    We investigate black holes formed by static perfect fluid with $p=-\\rho/3$. These represent the black holes in $S_3$ and $H_3$ spatial geometries. There are three classes of black-hole solutions, two $S_3$ types and one $H_3$ type. The interesting solution is the one of $S_3$ type which possesses two singularities. The one is at the north pole behind the horizon, and the other is naked at the south pole. The observers, however, are free from falling to the naked singularity. There are also nonstatic cosmological solutions in $S_3$ and $H_3$, and a singular static solution in $H_3$.

  19. On regular rotating black holes

    Science.gov (United States)

    Torres, R.; Fayos, F.

    2017-01-01

    Different proposals for regular rotating black hole spacetimes have appeared recently in the literature. However, a rigorous analysis and proof of the regularity of this kind of spacetimes is still lacking. In this note we analyze rotating Kerr-like black hole spacetimes and find the necessary and sufficient conditions for the regularity of all their second order scalar invariants polynomial in the Riemann tensor. We also show that the regularity is linked to a violation of the weak energy conditions around the core of the rotating black hole.

  20. Black Holes: A Traveler's Guide

    Science.gov (United States)

    Pickover, Clifford A.

    1998-03-01

    BLACK HOLES A TRAVELER'S GUIDE Clifford Pickover's inventive and entertaining excursion beyond the curves of space and time. "I've enjoyed Clifford Pickover's earlier books . . . now he has ventured into the exploration of black holes. All would-be tourists are strongly advised to read his traveler's guide." -Arthur C. Clarke. "Many books have been written about black holes, but none surpass this one in arousing emotions of awe and wonder towards the mysterious structure of the universe." -Martin Gardner. "Bucky Fuller thought big. Arthur C. Clarke thinks big, but Cliff Pickover outdoes them both." -Wired. "The book is fun, zany, in-your-face, and refreshingly addictive." -Times Higher Education Supplement.

  1. Can Black Hole Relax Unitarily?

    CERN Document Server

    Solodukhin, S N

    2004-01-01

    We review the way the BTZ black hole relaxes back to thermal equilibrium after a small perturbation and how it is seen in the boundary (finite volume) CFT. The unitarity requires the relaxation to be quasi-periodic. It is preserved in the CFT but is not obvious in the case of the semiclassical black hole the relaxation of which is driven by complex quasi-normal modes. We discuss two ways of modifying the semiclassical black hole geometry to maintain unitarity: the (fractal) brick wall and the worm-hole modification. In the latter case the entropy comes out correctly as well.

  2. Mobilizing Black America: Solutions to Black Health Problems

    Science.gov (United States)

    1993-04-01

    the most obese ethnic group in America. Too many black children are overweight because black adults feed them a steady diet of fatty and salty foods...start and elementary school children in the Early and Periodic Screening, Diagnosis, and Treatment (EPSDT) program. EPSDT has been instrumental in...blood cholesterol, obesity , unhealthy diets, and smoking are the leading causes (major risk factors) of these killers. The underlying problems associated

  3. Cryo-Etched Black Silicon for Use as Optical Black

    Science.gov (United States)

    Yee, Karl Y.; White, Victor E.; Mouroulis, Pantazis; Eastwood, Michael L.

    2011-01-01

    Stray light reflected from the surface of imaging spectrometer components in particular, the spectrometer slit degrade the image quality. A technique has been developed for rapid, uniform, and cost-effective black silicon formation based on inductively coupled plasma (ICP) etching at cryogenic temperatures. Recent measurements show less than 1-percent total reflectance from 350 2,500 nm of doped black silicon formed in this way, making it an excellent option for texturing of component surfaces for reduction of stray light. Oxygen combines with SF6 + Si etch byproducts to form a passivation layer atop the Si when the etch is performed at cryogenic temperatures. Excess flow of oxygen results in micromasking and the formation of black silicon. The process is repeatable and reliable, and provides control over etch depth and sidewall profile. Density of the needles can be controlled to some extent. Regions to be textured can be patterned lithographically. Adhesion is not an issue as the nanotips are part of the underlying substrate. This is in contrast to surface growth/deposition techniques such as carbon nanotubes (CNTs). The black Si surface is compatible with wet processing, including processing with solvents, the textured surface is completely inorganic, and it does not outgas. In radiometry applications, optical absorbers are often constructed using gold black or CNTs. This black silicon technology is an improvement for these types of applications.

  4. Accretion, primordial black holes and standard cosmology

    Indian Academy of Sciences (India)

    B Nayak; P Singh

    2011-01-01

    Primordial black holes evaporate due to Hawking radiation. We find that the evaporation times of primordial black holes increase when accretion of radiation is included. Thus, depending on accretion efficiency, more primordial black holes are existing today, which strengthens the conjecture that the primordial black holes are the proper candidates for dark matter.

  5. 7 CFR 51.1276 - Black end.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Black end. 51.1276 Section 51.1276 Agriculture... Standards for Summer and Fall Pears 1 Definitions § 51.1276 Black end. Black end is evidenced by an abnormally deep green color around the calyx, or black spots usually occurring on the one-third of...

  6. 7 CFR 51.1318 - Black end.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Black end. 51.1318 Section 51.1318 Agriculture... Standards for Winter Pears 1 Definitions § 51.1318 Black end. Black end is evidenced by an abnormally deep green color around the calyx, or black spots usually occurring on the one-third of the surface...

  7. Graduating Black Males: A Generic Qualitative Study

    Science.gov (United States)

    Bell, Edward E.

    2014-01-01

    Black males face a difficult educational battle. Across America, graduation statistics for Black males are sobering. The purpose of this study was to explore why Black males drop out of school and to examine the current employment status of the study participants. The research took place in rural North Carolina. Fifteen Black American male high…

  8. The Making of the Black Middle Class.

    Science.gov (United States)

    Collins, Sharon M.

    1983-01-01

    Examines Black occupational mobility and factors that have influenced the growth of the Black middle class since the 1960s. Argues that the Black middle class occupies a fragile market position because Black mobility depends on fluctuating government policy rather than on free market factors. (Author/MJL)

  9. The Core Journal Concept in Black Studies

    Science.gov (United States)

    Weissinger, Thomas

    2010-01-01

    Black Studies scholars have shown interest in the core journal concept. Indeed, the idea of core journals for the study of the Black experience has changed several times since 1940. While Black Studies scholars are citing Black Studies journals with frequency, they also cite traditional disciplinary journals a great deal of the time. However,…

  10. Homophobia, hypermasculinity and the US black church.

    Science.gov (United States)

    Ward, Elijah G

    2005-01-01

    Black churches in the USA constitute a significant source of the homophobia that pervades black communities. This theologically-driven homophobia is reinforced by the anti-homosexual rhetoric of black nationalism. Drawing on a variety of sources, this paper discusses the sources of homophobia within black communities, and its impact upon self-esteem, social relationships and physical health. Religion-based homophobia and black nationalism point to wider structures which have influenced their emergence, including racism, patriarchy and capitalism. It is vital for US black churches and communities to understand and transcend their longstanding resistance to openly addressing complex, painful issues of sexuality and embrace healthier definitions of black manhood.

  11. Magnetic Black Holes Are Also Unstable

    CERN Document Server

    Kim, Sang Pyo

    2004-01-01

    Most black holes are known to be unstable to emitting Hawking radiation (in asymptotically flat spacetime). If the black holes are non-extreme, they have positive temperature and emit thermally. If they are extremal rotating black holes, they still spontaneously emit particles like gravitons and photons. If they are extremal electrically charged black holes, they are unstable to emitting electrons or positrons. The only exception would be extreme magnetically charged black holes if there do not exist any magnetic monopoles for them to emit. However, here we show that even in this case, vacuum polarization causes all magnetic black holes to be unstable to emitting smaller magnetic black holes.

  12. How objective is black hole entropy?

    CERN Document Server

    Lau, Y K

    1994-01-01

    The objectivity of black hole entropy is discussed in the particular case of a Schwarzchild black hole. Using Jaynes' maximum entropy formalism and Euclidean path integral evaluation of partition function, it is argued that in the semiclassical limit when the fluctutation of metric is neglected, the black hole entropy of a Schwarzchild black hole is equal to the maximal information entropy of an observer whose sole knowledge of the black hole is its mass. Black hole entropy becomes a measure of number of its internal mass eigenstates in accordance with the Boltzmann principle only in the limit of negligible relative mass fluctutation. {}From the information theoretic perspective, the example of a Schwarzchild black hole seems to suggest that black hole entropy is no different from ordinary thermodynamic entropy. It is a property of the experimental data of a black hole, rather than being an intrinsic physical property of a black hole itself independent of any observer. However, it is still weakly objective in...

  13. Kerr black hole thermodynamical fluctuations

    Science.gov (United States)

    Pavon, D.; Rubi, J. M.

    1985-04-01

    The near-equilibrium thermodynamical (TD) fluctuations of a massive rotating uncharged Kerr black hole immersed in a uniformly corotating radiation bath at its temperature are investigated theoretically, generalizing Schwarzschild-black-hole analysis of Pavon and Rubi(1983), based on Einstein fluctuation theory. The correlations for the energy and angular moment fluctuations and the second moments of the other TD parameters are obtained, and the generalized second law of black-hole TD and the Bekenstein (1975) interpretation of black-hole entropy are seen as functioning well in this case. A local-stability criterion and relation for TD equilibrium between the Kerr hole and its own radiation in the flat-space-time limit are derived, and a restriction between C and Lambda is deduced.

  14. Black hole information vs. locality

    CERN Document Server

    Itzhaki, N

    1996-01-01

    We discuss the limitations on space time measurement in Schwarzchild metric. We find that near the horizon the limitations on space time measurement are of the order of the black hole radius. We suggest that it indicates that a large mass black hole can not be described by means of local field theory even at macroscopic distances and that any attempt to describe black hole formation and evaporation by means of an effective local field theory will necessarily lead to information loss. We also present a new interpretation of the black hole entropy which leads to S=cA , where c is a constant of order 1 which does not depend on the number of fields.

  15. Wire Jewelry/Black History.

    Science.gov (United States)

    Daniel, Robert A.; Robinson, Charles C.

    1984-01-01

    Described is a project which made the study of Black history more real to fifth graders by having them make wire jewelry, smaller versions of the ornate filigreed ironwork produced by slave blacksmiths. (RM)

  16. Black Liquid Solar Collector Demonstrator.

    Science.gov (United States)

    Weichman, F. L.; Austen, D. J.

    1979-01-01

    Describes the details of constructing, and use of, a solar collector. Uses a black liquid to absorb the energy, the thermosyphon effect to drive the liquid through the collector, and a floodlamp as a surrogate sun. (GA)

  17. 'Black holes': escaping the void.

    Science.gov (United States)

    Waldron, Sharn

    2013-02-01

    The 'black hole' is a metaphor for a reality in the psyche of many individuals who have experienced complex trauma in infancy and early childhood. The 'black hole' has been created by an absence of the object, the (m)other, so there is no internalized object, no (m)other in the psyche. Rather, there is a 'black hole' where the object should be, but the infant is drawn to it, trapped by it because of an intrinsic, instinctive need for a 'real object', an internalized (m)other. Without this, the infant cannot develop. It is only the presence of a real object that can generate the essential gravity necessary to draw the core of the self that is still in an undeveloped state from deep within the abyss. It is the moving towards a real object, a (m)other, that relativizes the absolute power of the black hole and begins a reformation of its essence within the psyche.

  18. Formation of Supermassive Black Holes

    CERN Document Server

    Volonteri, Marta

    2010-01-01

    Evidence shows that massive black holes reside in most local galaxies. Studies have also established a number of relations between the MBH mass and properties of the host galaxy such as bulge mass and velocity dispersion. These results suggest that central MBHs, while much less massive than the host (~ 0.1%), are linked to the evolution of galactic structure. In hierarchical cosmologies, a single big galaxy today can be traced back to the stage when it was split up in hundreds of smaller components. Did MBH seeds form with the same efficiency in small proto-galaxies, or did their formation had to await the buildup of substantial galaxies with deeper potential wells? I briefly review here some of the physical processes that are conducive to the evolution of the massive black hole population. I will discuss black hole formation processes for `seed' black holes that are likely to place at early cosmic epochs, and possible observational tests of these scenarios.

  19. Black holes and quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Hooft, G. ' t, E-mail: g.thooft@uu.n [Institute for Theoretical Physics, Utrecht University and Spinoza Institute, P.O. Box 80.195, 3508 TD Utrecht (Netherlands)

    2010-07-15

    After a brief review of quantum black hole physics, it is shown how the dynamical properties of a quantum black hole may be deduced to a large extent from Standard Model Physics, extended to scales near the Planck length, and combined with results from perturbative quantum gravity. Together, these interactions generate a Hilbert space of states on the black hole horizon, which can be investigated, displaying interesting systematics by themselves. To make such approaches more powerful, a study is made of the black hole complementarity principle, from which one may deduce the existence of a hidden form of local conformal invariance. Finally, the question is raised whether the principles underlying Quantum Mechanics are to be sharpened in this domain of physics as well. There are intriguing possibilities.

  20. Recoiling Black Holes in Quasars

    CERN Document Server

    Bonning, E W; Salviander, S

    2007-01-01

    Recent simulations of merging black holes with spin give recoil velocities from gravitational radiation up to several thousand km/s. A recoiling supermassive black hole can retain the inner part of its accretion disk, providing fuel for a continuing QSO phase lasting millions of years as the hole moves away from the galactic nucleus. One possible observational manifestation of a recoiling accretion disk is in QSO emission lines shifted in velocity from the host galaxy. We have examined QSOs from the Sloan Digital Sky Survey with broad emission lines substantially shifted relative to the narrow lines. We find no convincing evidence for recoiling black holes carrying accretion disks. We place an upper limit on the incidence of recoiling black holes in QSOs of 4% for kicks greater than 500 km/s and 0.35% for kicks greater than 1000 km/s line-of-sight velocity.

  1. Singularities Inside Hairy Black Holes

    OpenAIRE

    Gal'tsov, D. V.; Donets, E. E.; Zotov, M. Yu.

    1997-01-01

    We show that the Strong Cosmic Censorship is supported by the behavior of generic solutions on the class of static spherically symmetric black holes in gravitating gauge models and their stringy generalizations.

  2. Singularities Inside Hairy Black Holes

    CERN Document Server

    Galtsov, D V; Zotov, M Yu

    1998-01-01

    We show that the Strong Cosmic Censorship is supported by the behavior of generic solutions on the class of static spherically symmetric black holes in gravitating gauge models and their stringy generalizations.

  3. Black hole accretion disc impacts

    CERN Document Server

    Pihajoki, Pauli

    2015-01-01

    We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength {\\lambda} = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.

  4. Space, time, and black holes

    Energy Technology Data Exchange (ETDEWEB)

    Darling, D.

    1980-10-01

    A discussion of Einstein's General Relativity and how it can explain black holes is included. The key idea of general relativity being that gravitational forces are a direct outcome of local curvature of space-time. The more mass something has the deeper the depression or well it causes in space-time. Black holes are supermassive objects, hence their gravity well is so steep even light can't escape. The three properties associated with a black hole are mass angular momentum, and electric charge. Non-rotating, Schwarzchild, and rotating, Kerr, black holes are studied. A Kruskal-Szekeres diagram for each type is given and explained. (SC)

  5. The Black Hole Universe Model

    Science.gov (United States)

    Zhang, Tianxi

    2014-06-01

    The black hole universe model is a multiverse model of cosmology recently developed by the speaker. According to this new model, our universe is a fully grown extremely supermassive black hole, which originated from a hot star-like black hole with several solar masses, and gradually grew up from a supermassive black hole with million to billion solar masses to the present state with trillion-trillion solar masses by accreting ambient matter or merging with other black holes. The entire space is structured with infinite layers or universes hierarchically. The innermost three layers include the universe that we live, the inside star-like and supermassive black holes called child universes, and the outside space called mother universe. The outermost layer is infinite in mass, radius, and entropy without an edge and limits to zero for both the matter density and absolute temperature. All layers are governed by the same physics and tend to expand physically in one direction (outward or the direction of increasing entropy). The expansion of a black hole universe decreases its density and temperature but does not alter the laws of physics. The black hole universe evolves iteratively and endlessly without a beginning. When one universe expands out, a new similar one is formed from inside star-like and supermassive black holes. In each of iterations, elements are resynthesized, matter is reconfigurated, and the universe is renewed rather than a simple repeat. The black hole universe is consistent with the Mach principle, observations, and Einsteinian general relativity. It has only one postulate but is able to explain all phenomena occurred in the universe with well-developed physics. The black hole universe does not need dark energy for acceleration and an inflation epoch for flatness, and thus has a devastating impact on the big bang model. In this talk, I will present how this new cosmological model explains the various aspects of the universe, including the origin

  6. Geometric inequalities for black holes

    CERN Document Server

    Dain, Sergio

    2014-01-01

    It is well known that the three parameters that characterize the Kerr black hole (mass, angular momentum and horizon area) satisfy several important inequalities. Remarkably, some of these inequalities remain valid also for dynamical black holes. This kind of inequalities play an important role in the characterization of the gravitational collapse. They are closed related with the cosmic censorship conjecture. In this article recent results in this subject are reviewed.

  7. Tensor Network and Black Hole

    CERN Document Server

    Matsueda, Hiroaki; Hashizume, Yoichiro

    2012-01-01

    A tensor network formalism of thermofield dynamics is introduced. The formalism relates the original Hilbert space with its tilde space by a product of two copies of a tensor network. Then, their interface becomes an event horizon, and the logarithm of the tensor rank corresponds to the black hole entropy. Eventually, multiscale entanglement renormalization anzats (MERA) reproduces an AdS black hole at finite temperature. Our finding shows rich functionalities of MERA as efficient graphical representation of AdS/CFT correspondence.

  8. 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.

  9. Evolution of supermassive black holes

    CERN Document Server

    Volonteri, M

    2006-01-01

    Supermassive black holes (SMBHs) are nowadays believed to reside in most local galaxies, and the available data show an empirical correlation between bulge luminosity - or stellar velocity dispersion - and black hole mass, suggesting a single mechanism for assembling black holes and forming spheroids in galaxy halos. The evidence is therefore in favour of a co-evolution between galaxies, black holes and quasars. In cold dark matter cosmogonies, small-mass subgalactic systems form first to merge later into larger and larger structures. In this paradigm galaxy halos experience multiple mergers during their lifetime. If every galaxy with a bulge hosts a SMBH in its center, and a local galaxy has been made up by multiple mergers, then a black hole binary is a natural evolutionary stage. The evolution of the supermassive black hole population clearly has to be investigated taking into account both the cosmological framework and the dynamical evolution of SMBHs and their hosts. The seeds of SMBHs have to be looked ...

  10. Intermediate-Mass Black Holes

    CERN Document Server

    Miller, M C

    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 (roughly 3-20 solar masses), which are produced by the core collapse of massive stars, and supermassive (millions to billions of solar masses), 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 hundreds to thousands of solar masses. 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 t...

  11. Bounds on Black Hole Spins

    CERN Document Server

    Daly, Ruth A

    2009-01-01

    Beam powers and black hole masses of 48 extended radio sources are combined to obtain lower bounds on the spins and magnetic field strengths of supermassive black holes. This is done in the context of the models of Blandford & Znajek (1977) (the 'BZ' model) and Meier (1999); a parameterization for bounds in the context of other models is suggested. The bounds obtained for very powerful classical double radio sources in the BZ model are consistent with black hole spins of order unity for sources at high redshift. The black hole spins are largest for the highest redshift sources and decrease for sources at lower redshift; the sources studied have redshifts between zero and two. Lower power radio sources associated with central dominant galaxies may have black hole spins that are significantly less than one. Combining this analysis with other results suggests that the maximum values of black hole spin associated with powerful radio galaxies decline from values of order unity at a redshift of 2 to values of o...

  12. Black Box QGP

    CERN Document Server

    Tawfik, A

    2006-01-01

    According to extensive ab initio calculations of lattice QCD, the very large energy density available in heavy-ion collisions at SPS and now at RHIC must be sufficient to generate quark-gluon plasma (QGP), a new state of matter in the form of plasma of free quarks and gluons. The new state of matter discovered at RHIC seems to be perfect fluid rather than free plasma. Its shear viscosity is assumed to be almost zero. In this work, I first considered the theoretical and phenomenological consequences of this discovery and finally asked questions about the nature of phase transition and properties of matter. It is important to answer these questions, otherwise QGP will remain a kind of black box; one sends a signal via new experiments or simulations or models and gets another one from it. I will show that some promising ideas have already been suggested a long time ago. I will also suggest a new phase diagram with separated deconfinement and freeze-out boundaries and a mixed state of thermal quark matter and bub...

  13. Black hole meiosis

    Science.gov (United States)

    van Herck, Walter; Wyder, Thomas

    2010-04-01

    The enumeration of BPS bound states in string theory needs refinement. Studying partition functions of particles made from D-branes wrapped on algebraic Calabi-Yau 3-folds, and classifying states using split attractor flow trees, we extend the method for computing a refined BPS index, [1]. For certain D-particles, a finite number of microstates, namely polar states, exclusively realized as bound states, determine an entire partition function (elliptic genus). This underlines their crucial importance: one might call them the ‘chromosomes’ of a D-particle or a black hole. As polar states also can be affected by our refinement, previous predictions on elliptic genera are modified. This can be metaphorically interpreted as ‘crossing-over in the meiosis of a D-particle’. Our results improve on [2], provide non-trivial evidence for a strong split attractor flow tree conjecture, and thus suggest that we indeed exhaust the BPS spectrum. In the D-brane description of a bound state, the necessity for refinement results from the fact that tachyonic strings split up constituent states into ‘generic’ and ‘special’ states. These are enumerated separately by topological invariants, which turn out to be partitions of Donaldson-Thomas invariants. As modular predictions provide a check on many of our results, we have compelling evidence that our computations are correct.

  14. Black Hole Meiosis

    CERN Document Server

    Van Herck, Walter

    2009-01-01

    The enumeration of BPS bound states in string theory needs refinement. Studying partition functions of particles made from D-branes wrapped on algebraic Calabi-Yau 3-folds, and classifying states using split attractor flow trees, we extend the method for computing a refined BPS index, arXiv:0810.4301. For certain D-particles, a finite number of microstates, namely polar states, exclusively realized as bound states, determine an entire partition function (elliptic genus). This underlines their crucial importance: one might call them the `chromosomes' of a D-particle or a black hole. As polar states also can be affected by our refinement, previous predictions on elliptic genera are modified. This can be metaphorically interpreted as `crossing-over in the meiosis of a D-particle'. Our results improve on hep-th/0702012, provide non-trivial evidence for a strong split attractor flow tree conjecture, and thus suggest that we indeed exhaust the BPS spectrum. In the D-brane description of a bound state, the necessity...

  15. Black, White and Grey

    Directory of Open Access Journals (Sweden)

    Nasrin Nooshfar

    2011-05-01

    Full Text Available Background/Objective: Development of science and"nart achieved with saving independence, separation"nclassification and studying their details. The other hand"nis combination of these to create a new world with"nwide dimensions and take a place to human needs."nMaterials and Methods: Our attempt is to make"nhealth-care places pleasant and attractive for patients."nWe offer best services, but they are not comfortable"nand happy in these places. They are afraid of the staff,"nequipment and the environment. For this purpose"nwe mixed the brightness and darkness of radiologic"nimages with white and black photographs or paintings"ncomplementary to create analog artistic images that"ncould be converted to digital printing by DICOM"ninterfaces on hard copies."nConclusion: Fear, pictures a bad memory in the"npatient's mind forever. We mixed radiology and"nimaging with photography as a science and art mixture"nto conflict with these problems, it is more effective in"nchildren who are suffering from social and known"ndiseases and can not adapt themselves with their"nsituations. This could create a good memory between"nthe human body image and sentimental experience."nIn the literature, printed radiologic images were used"nas fine art on glass and paper, metal and flowers were"nemployed to mix.* *Wim Delvoye (born 1965 ,Wervik"nand Steven N.Meyers and Merille Raikes

  16. The Black Box QGP

    CERN Document Server

    Tawfik, A

    2006-01-01

    According to the extensive ab initio calculations of lattice QCD, the much large energy density available in the heavy-ion collisions at SPS and now at RHIC should be enough to create the quark-gluon plasma (QGP); a new state of matter in form plasma of free quarks and gluons. The new matter discovered at RHIC is a ''nearly perfect'' fluid rather than a plasma. The shear viscosity is too small. We should then ask about the theoretical and phenomenological consequences and why we simply assumed that the deconfined hadronic matter should be an ideal gas. Finally, I will address five questions; about the properties of the new phases at high temperatures and the orders of phase transitions. Before we clarify such questions, the QGP will remain a kind of black box. One sends a signal via new experiments or simulations and gets another one out if it. Then one try to explain what is going on. I will show that some promising ideas already have been suggested long time ago, but it seems that community didn't care. Is ...

  17. How Black Holes Burn

    CERN Document Server

    Brustein, Ram

    2014-01-01

    We present a calculation of the rate of information release from a Schwarzschild BH. We have recently extended Hawking's theory of black hole (BH) evaporation to account for quantum fluctuations of the background geometry, as well as for back-reaction and time-dependence effects. Our main result has been a two-point function matrix for the radiation that consists of Hawking's thermal matrix plus off-diagonal corrections that are initially small and become more important as the evaporation proceeds. Here, we show that, if the phases and amplitudes of the radiation matrix are recorded over the lifetime of the BH, then the radiation purifies in a continuous way. We conjecture that our results establish the maximal rate at which information can be released from a semiclassical BH, to be contrasted with the minimal rate that was predicted by Page on the basis of generic unitarity arguments. When the phases of the radiation matrix are not tracked, we show that it purifies only parametrically close to the end of the...

  18. Erratic Black Hole Regulates Itself

    Science.gov (United States)

    2009-03-01

    New results from NASA's Chandra X-ray Observatory have made a major advance in explaining how a special class of black holes may shut off the high-speed jets they produce. These results suggest that these black holes have a mechanism for regulating the rate at which they grow. Black holes come in many sizes: the supermassive ones, including those in quasars, which weigh in at millions to billions of times the mass of the Sun, and the much smaller stellar-mass black holes which have measured masses in the range of about 7 to 25 times the Sun's mass. Some stellar-mass black holes launch powerful jets of particles and radiation, like seen in quasars, and are called "micro-quasars". The new study looks at a famous micro-quasar in our own Galaxy, and regions close to its event horizon, or point of no return. This system, GRS 1915+105 (GRS 1915 for short), contains a black hole about 14 times the mass of the Sun that is feeding off material from a nearby companion star. As the material swirls toward the black hole, an accretion disk forms. This system shows remarkably unpredictable and complicated variability ranging from timescales of seconds to months, including 14 different patterns of variation. These variations are caused by a poorly understood connection between the disk and the radio jet seen in GRS 1915. Chandra, with its spectrograph, has observed GRS 1915 eleven times since its launch in 1999. These studies reveal that the jet in GRS 1915 may be periodically choked off when a hot wind, seen in X-rays, is driven off the accretion disk around the black hole. The wind is believed to shut down the jet by depriving it of matter that would have otherwise fueled it. Conversely, once the wind dies down, the jet can re-emerge. "We think the jet and wind around this black hole are in a sort of tug of war," said Joseph Neilsen, Harvard graduate student and lead author of the paper appearing in the journal Nature. "Sometimes one is winning and then, for reasons we don

  19. Resource Letter BH-2: Black Holes

    CERN Document Server

    Gallo, Elena

    2008-01-01

    This resource letter is designed to guide students, educators, and researchers through (some of) the literature on black holes. Both the physics and astrophysics of black holes are discussed. Breadth has been emphasized over depth, and review articles over primary sources. We include resources ranging from non-technical discussions appropriate for broad audiences to technical reviews of current research. Topics addressed include classification of stationary solutions, perturbations and stability of black holes, numerical simulations, collisions, the production of gravity waves, black hole thermodynamics and Hawking radiation, quantum treatments of black holes, black holes in both higher and lower dimensions, and connections to nuclear and condensed matter physics. On the astronomical end, we also cover the physics of gas accretion onto black holes, relativistic jets, gravitationally red-shifted emission lines, evidence for stellar-mass black holes in binary systems and super-massive black holes at the centers...

  20. Could supermassive black holes be quintessential primordial black holes?

    CERN Document Server

    Bean, R; Bean, Rachel; Magueijo, Joao

    2002-01-01

    There is growing observational evidence for a population of supermassive black holes (SMBHs) in galactic bulges. We examine in detail the conditions under which these black holes must have originated from primordial black holes (PBHs). We consider the merging and accretion history experienced by SMBHs to find that, whereas it is possible that they were formed by purely astrophysical processes, this is unlikely and most probably a populations of primordial progenitors is necessary. We identify the mass distribution and comoving density of this population and then propose a cosmological scenario producing PBHs with the right properties. Although this is not essential we consider PBHs produced at the end of a period of inflation with a blue spectrum of fluctuations. We constrain the value of the spectral tilt in order to obtain the required PBH comoving density. We then assume that PBHs grow by accreting quintessence showing that their mass scales like the horizon mass while the quintessence field itself is scal...

  1. Massless black holes as black diholes and quadruholes

    CERN Document Server

    Ortín, Tomas

    1996-01-01

    Massless black holes can be understood as bound states of a (positive mass) extreme a=\\sqrt{3} black hole and a singular object with opposite ({\\it i.e.}~negative) mass with vanishing ADM (total) mass but non-vanishing gravitational field. Supersymmetric balance of forces is crucial for the existence of this kind of bound states and explains why the system does not move at the speed of light in spite of being massless. We also explain how supersymmetry allows for negative mass as long as it is never isolated but in bound states of total non-negative mass. The known massless black-hole solutions should then be considered particular cases of ``gravitational dipoles''. We also present ``gravitational quadrupoles'' and comment on the possible role of all these objects in string phase transitions.

  2. Sublethal concentrations of salicylic acid decrease the formation of reactive oxygen species but maintain an increased nitric oxide production in the root apex of the ethylene-insensitive never ripe tomato mutants.

    Science.gov (United States)

    Tari, Irma; Poór, Péter; Gémes, Katalin

    2011-09-01

    The pattern of salicylic acid (SA)-induced production of reactive oxygen species (ROS) and nitric oxide (NO) were different in the apex of adventitious roots in wild-type and in the ethylene-insensitive never ripe (Nr) mutants of tomato (Solanum lycopersicum L. cv Ailsa Craig). ROS were upregulated, while NO remained at the control level in apical root tissues of wildtype plants exposed to sublethal concentrations of SA. In contrast, Nr plants expressing a defective ethylene receptor displayed a reduced level of RO S and a higher NO content in the apical root cells. In wild-type plants NO production seems to be RO S(H2O2)-dependent at cell death-inducing concentrations of SA, indicating that ROS and NO may interact to trigger oxidative cell death. In the absence of significant RO S accumulation, the increased NO production caused moderate reduction in cell viability in root apex of Nr plants exposed to 10(-3) M SA. This suggests that a functional ethylene signaling pathway is necessary for the control of ROS and NO production induced by SA.

  3. Information locking in black holes

    CERN Document Server

    Smolin, J; Smolin, John; Oppenheim, Jonathan

    2005-01-01

    The black hole information loss paradox has plagued physicists since Hawking's discovery that black holes evaporate. The calculation suggests that information thrown into a black hole is evaporated away as thermal radiation, and is destroyed: either the unitary laws of quantum theory break down, or we must modify the laws of general relativity. Here we show that one of the central presumptions of the debate is incorrect. Ensuring that information not escape during the semi-classical evaporation process does not require that all the information remain in the black hole until the final stages of evaporation. By taking into account recent results in quantum information theory, we find that the amount of information that must remain in the black hole until the final stages of evaporation can be very small, even though the amount of information which has already radiated away is negligible. Quantum effects mean that information need not be additive: a small number of quanta can lock a large amount of information, ...

  4. Black Holes: The Membrane Viewpoint

    Science.gov (United States)

    Thorne, Kip S.

    Contents: I. Introduction: 1. Overview of the membrane viewpoint. 2. History of research on the membrane viewpoint. II. The 3+1 split of spacetime: 1. ZAMOs and the 3+1 split of the metric. 2. Gravitoelectric and gravitomagnetic fields. 3. 3+1 split of electrodynamics. III. Stretching the horizon and black-hole thermodynamics: 1. Macdonald's vibrating magnetic field problem. 2. Stretching the horizon. 3. The entropy of a black hole. 4. The thermodynamics and mechanics of a black hole. IV. Electrodynamics of the stretched horizon: 1. The laws of Gauss, Ampere, Ohm, and charge conservation. 2. Lorentz force and ohmic dissipation in the stretched horizon. V. Some electromagnetic model problems: 1. Charge separation in the stretched horizon. 2. Black hole as a resistor in an electric circuit. 3. Black hole as the rotor in an electric motor. 4. Rotating hole immersed in a time-independent, vacuum magnetic field. 5. Magnetized, rotating hole as a battery for an external circuit. VI. Astrophysical applications of the membrane formalism. VII. Conclusion.

  5. Astrophysical Black Holes: Evidence of a Horizon?

    Science.gov (United States)

    Colpi, Monica

    In this Lecture Note we first follow a short account of the history of the black hole hypothesis. We then review on the current status of the search for astrophysical black holes with particular attention to the black holes of stellar origin. Later, we highlight a series of observations that reveal the albeit indirect presence of supermassive black holes in galactic nuclei, with mention to forthcoming experiments aimed at testing directly the black hole hypothesis. We further focus on evidences of a black hole event horizon in cosmic sources.

  6. Black di-ring and infinite nonuniqueness

    CERN Document Server

    Iguchi, H; Iguchi, Hideo; Mishima, Takashi

    2007-01-01

    We show that the $S^1$-rotating black rings can be superposed by the solution generating technique. We analyze the black di-ring solution for the simplest case of multiple rings. There exists an equilibrium black di-ring where the conical singularities are cured by the suitable choice of physical parameters. Also there are infinite numbers of black di-rings with the same mass and angular momentum. These di-rings can have two different continuous limits of single black rings. Therefore we can transform the fat black ring to the thin ring with the same mass and angular momentum by way of the di-ring solutions.

  7. Supersymmetric black holes in string theory

    Energy Technology Data Exchange (ETDEWEB)

    Mohaupt, T. [Theoretical Physics Division, Department of Mathematical Sciences, University of Liverpool, Peach Street, Liverpool L69 7ZL (United Kingdom)

    2007-05-15

    We review recent developments concerning supersymmetric black holes in string theory. After a general introduction to the laws of black hole mechanics and to black hole entropy in string theory, we discuss black hole solutions in N=2 supergravity, special geometry, the black hole attractor equations and the underlying variational principle. Special attention is payed to the crucial role of higher derivative corrections. Finally we discuss black hole partition functions and their relation with the topological string, mainly from the supergravity perspective. We summarize the state of art and discuss various open questions and problems. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  8. Black Hole Blows Big Bubble

    Science.gov (United States)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  9. Lee-Wick Black Holes

    CERN Document Server

    Bambi, Cosimo; Wang, Yixu

    2016-01-01

    We derive and study an approximate static vacuum solution generated by a point-like source in a higher derivative gravitational theory with a pair of complex conjugate ghosts. The gravitational theory is local and characterized by a high derivative operator compatible with Lee-Wick unitarity. In particular, the tree-level two-point function only shows a pair of complex conjugate poles besides the massless spin two graviton. We show that singularity-free black holes exist when the mass of the source $M$ exceeds a critical value $M_{\\rm crit}$. For $M > M_{\\rm crit}$ the spacetime structure is characterized by an outer event horizon and an inner Cauchy horizon, while for $M = M_{\\rm crit}$ we have an extremal black hole with vanishing Hawking temperature. The evaporation process leads to a remnant that approaches the zero-temperature extremal black hole state in an infinite amount of time.

  10. Black lenses in string theory

    CERN Document Server

    Kunduri, Hari K

    2016-01-01

    We present a new supersymmetric, asymptotically flat, black hole solution to five-dimensional U(1)^3-supergravity which is regular on and outside an event horizon of lens space topology L(2,1). The solution has seven independent parameters and uplifts to a new family of 1/8-supersymmetric D1-D5-P black brane solutions to Type IIB supergravity. The decoupling limit is asymptotically AdS(3) x S^3 x T^4, with a near-horizon geometry that is a twisted product of the near-horizon geometry of the extremal BTZ black hole and L(2,1) x T^4, although it is not (locally) a product space in the bulk. Nevertheless, we find that the Bekenstein-Hawking entropy agrees exactly with the Cardy formula for the degeneracy of CFT states dual to the near-horizon geometry.

  11. Volume inside old black holes

    Science.gov (United States)

    Christodoulou, Marios; De Lorenzo, Tommaso

    2016-11-01

    Black holes that have nearly evaporated are often thought of as small objects, due to their tiny exterior area. However, the horizon bounds large spacelike hypersurfaces. A compelling geometric perspective on the evolution of the interior geometry was recently shown to be provided by a generally covariant definition of the volume inside a black hole using maximal surfaces. In this article, we expand on previous results and show that finding the maximal surfaces in an arbitrary spherically symmetric spacetime is equivalent to a 1 +1 geodesic problem. We then study the effect of Hawking radiation on the volume by computing the volume of maximal surfaces inside the apparent horizon of an evaporating black hole as a function of time at infinity: while the area is shrinking, the volume of these surfaces grows monotonically with advanced time, up to when the horizon has reached Planckian dimensions. The physical relevance of these results for the information paradox and the remnant scenarios are discussed.

  12. Black holes and galaxy formation

    CERN Document Server

    Propst, Raphael J

    2010-01-01

    Galaxies are the basic unit of cosmology. The study of galaxy formation is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning. The physics of galaxy formation is complicated because it deals with the dynamics of stars, thermodynamics of gas and energy production of stars. A black hole is a massive object whose gravitational field is so intense that it prevents any form of matter or radiation to escape. It is hypothesized that the most massive galaxies in the universe- "elliptical galaxies"- grow simultaneously with the supermassive black holes at their centers, giving us much stronger evidence that black holes control galaxy formation. This book reviews new evidence in the field.

  13. Life under a black sun

    Science.gov (United States)

    Opatrný, Tomáš; Richterek, Lukáš; Bakala, Pavel

    2017-01-01

    Life is dependent on the income of energy with low entropy and the disposal of energy with high entropy. On Earth, the low-entropy energy is provided by solar radiation and the high-entropy energy is disposed of as infrared radiation emitted into cold space. Here, we turn the situation around and imagine the cosmic background radiation as the low-entropy source of energy for a planet orbiting a black hole into which the high-entropy energy is expelled. We estimate the power that can be produced by thermodynamic processes on such a planet, with a particular interest in planets orbiting a fast rotating Kerr black hole as in the science fiction movie Interstellar. We also briefly discuss a reverse Dyson sphere absorbing cosmic background radiation from the outside and dumping waste energy to a black hole inside.

  14. Edge phonons in black phosphorus

    Science.gov (United States)

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.

    2016-07-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements.

  15. Disrupting Entanglement of Black Holes

    CERN Document Server

    Leichenauer, Stefan

    2014-01-01

    We study entanglement in thermofield double states of strongly coupled CFTs by analyzing two-sided Reissner-Nordstrom solutions in AdS. The central object of study is the mutual information between a pair of regions, one on each asymptotic boundary of the black hole. For large regions the mutual information is positive and for small ones it vanishes; we compute the critical length scale, which goes to infinity for extremal black holes, of the transition. We also generalize the butterfly effect of Shenker and Stanford to a wide class of charged black holes, showing that mutual information is disrupted upon perturbing the system and waiting for a time of order $\\log E/\\delta E$ in units of the temperature. We conjecture that the parametric form of this timescale is universal.

  16. Lee-Wick black holes

    Science.gov (United States)

    Bambi, Cosimo; Modesto, Leonardo; Wang, Yixu

    2017-01-01

    We derive and study an approximate static vacuum solution generated by a point-like source in a higher derivative gravitational theory with a pair of complex conjugate ghosts. The gravitational theory is local and characterized by a high derivative operator compatible with Lee-Wick unitarity. In particular, the tree-level two-point function only shows a pair of complex conjugate poles besides the massless spin two graviton. We show that singularity-free black holes exist when the mass of the source M exceeds a critical value Mcrit. For M >Mcrit the spacetime structure is characterized by an outer event horizon and an inner Cauchy horizon, while for M =Mcrit we have an extremal black hole with vanishing Hawking temperature. The evaporation process leads to a remnant that approaches the zero-temperature extremal black hole state in an infinite amount of time.

  17. Scrambling with matrix black holes

    Science.gov (United States)

    Brady, Lucas; Sahakian, Vatche

    2013-08-01

    If black holes are not to be dreaded sinks of information but rather fully described by unitary evolution, they must scramble in-falling data and eventually leak it through Hawking radiation. Sekino and Susskind have conjectured that black holes are fast scramblers; they generate entanglement at a remarkably efficient rate, with the characteristic time scaling logarithmically with the entropy. In this work, we focus on Matrix theory—M-theory in the light-cone frame—and directly probe the conjecture. We develop a concrete test bed for quantum gravity using the fermionic variables of Matrix theory and show that the problem becomes that of chains of qubits with an intricate network of interactions. We demonstrate that the black hole system evolves much like a Brownian quantum circuit, with strong indications that it is indeed a fast scrambler. We also analyze the Berenstein-Maldacena-Nastase model and reach the same tentative conclusion.

  18. Life under a black sun

    CERN Document Server

    Opatrný, Tomáš; Bakala, Pavel

    2016-01-01

    Life is dependent on the income of energy with low entropy and the disposal of energy with high entropy. On Earth, the low-entropy energy is provided by solar radiation and the high-entropy energy is disposed as infrared radiation emitted into the cold space. Here we turn the situation around and assume cosmic background radiation as the low-entropy source of energy for a planet orbiting a black hole into which the high-entropy energy is disposed. We estimate the power that can be produced by thermodynamic processes on such a planet, with a particular interest in planets orbiting a fast rotating Kerr black hole as in the science fiction movie {\\em Interstellar}. We also briefly discuss a reverse Dyson sphere absorbing cosmic background radiation from the outside and dumping waste energy to a black hole inside.

  19. Calabi-Yau black holes

    Science.gov (United States)

    Shmakova, Marina

    1997-07-01

    We find the entropy of N=2 extreme black holes associated with general Calabi-Yau moduli space and the prepotential F=dABC(XAXBXC/X0). We show that for arbitrary dABC and black hole charges p and q the entropy-area formula depends on combinations of these charges and parameters dABC. These combinations are the solutions of a simple system of algebraic equations. We give a few examples of particular Calabi-Yau moduli spaces for which this system has an explicit solution. For the special case when one of the black hole charges is equal to zero (p0=0) the solution always exists.

  20. Black holes with vector hair

    Science.gov (United States)

    Fan, Zhong-Ying

    2016-09-01

    In this paper, we consider Einstein gravity coupled to a vector field, either minimally or non-minimally, together with a vector potential of the type V = 2{Λ}_0+1/2{m}^2{A}^2 + {γ}_4{A}^4 . For a simpler non-minimally coupled theory with Λ0 = m = γ4 = 0, we obtain both extremal and non-extremal black hole solutions that are asymptotic to Minkowski space-times. We study the global properties of the solutions and derive the first law of thermodynamics using Wald formalism. We find that the thermodynamical first law of the extremal black holes is modified by a one form associated with the vector field. In particular, due to the existence of the non-minimal coupling, the vector forms thermodynamic conjugates with the graviton mode and partly contributes to the one form modifying the first law. For a minimally coupled theory with Λ0 ≠ 0, we also obtain one class of asymptotically flat extremal black hole solutions in general dimensions. This is possible because the parameters ( m 2 , γ4) take certain values such that V = 0. In particular, we find that the vector also forms thermodynamic conjugates with the graviton mode and contributes to the corresponding first law, although the non-minimal coupling has been turned off. Thus all the extremal black hole solutions that we obtain provide highly non-trivial examples how the first law of thermodynamics can be modified by a either minimally or non-minimally coupled vector field. We also study Gauss-Bonnet gravity non-minimally coupled to a vector and obtain asymptotically flat black holes and Lifshitz black holes.

  1. Geometric inequalities for black holes

    Energy Technology Data Exchange (ETDEWEB)

    Dain, Sergio [Universidad Nacional de Cordoba (Argentina)

    2013-07-01

    Full text: A geometric inequality in General Relativity relates quantities that have both a physical interpretation and a geometrical definition. It is well known that the parameters that characterize the Kerr-Newman black hole satisfy several important geometric inequalities. Remarkably enough, some of these inequalities also hold for dynamical black holes. This kind of inequalities, which are valid in the dynamical and strong field regime, play an important role in the characterization of the gravitational collapse. They are closed related with the cosmic censorship conjecture. In this talk I will review recent results in this subject. (author)

  2. Black holes and warped spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, W.J. III

    1979-01-01

    Black holes (BHs) and their warping effect on spacetime are described, beginning with a discussion on stellar evolution that includes white dwarfs, supernovas and neutron stars. The structure of static, rotating, and electrically charged BHs are considered, as well as the general theory of relativity, quantum mechanics, the Einstein-Rosen bridge, and wormholes in spacetime. Attention is also given to gravitational lenses, various space geometries, quasars, Seyfert galaxies, supermassive black holes, the evaporation and particle emission of BHs, and primordial BHs, including their temperature and lifetime.

  3. Black Holes with Zero Mass

    CERN Document Server

    Nucamendi, U; Nucamendi, Ulises; Sudarsky, Daniel

    2000-01-01

    We consider the spacetimes corresponding to static Global Monopoles with interior boundaries corresponding to a Black Hole Horizon and analyze the behavior of the appropriate ADM mass as a function of the horizon radius r_H. We find that for small enough r_H, this mass is negative as in the case of the regular global monopoles, but that for large enough r_H the mass becomes positive encountering an intermediate value for which we have a Black Hole with zero ADM mass.

  4. Irreversible gravitational collapse: black stars or black holes?

    CERN Document Server

    Corda, Christian

    2011-01-01

    It is well known that the concept of black hole has been considered very fascinating by scientists even before the introduction of Einstein's general relativity. They should be the final result of an irreversible gravitational collapse of very massive bodies. However, an unsolved problem concerning such objects is the presence of a space-time singularity in their core. Such a problem was present starting by the first historical papers concerning black holes. It is a common opinion that this problem could be solved when a correct quantum gravity theory will be, finally, constructed. In this work we review a way to remove black hole singularities at a classical level i.e. without arguments of quantum gravity. By using a particular non-linear electrodynamics Lagrangian, an exact solution of Einstein field equations is shown. The solution prevents the collapsing object to reach the gravitational radius, thus the final result becomes a black star, i.e. an astrophysical object where both of singularities and event ...

  5. Moodulitest komplekteeritav diivan Black = A modular sofa called Black

    Index Scriptorium Estoniae

    2007-01-01

    Autor Tiina Mang pälvis diivanikomplekti Black eest Eesti Sisearhitektide Liidu 2006. a. esemepreemia. T. Mangist, objektid, kuhu on valitud T. Mangi projekteeritud mööblit, näitused. 3 värv. vaadet, foto T. Mangist

  6. New Geometries for Black Hole Horizons

    CERN Document Server

    Armas, Jay

    2015-01-01

    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 he...

  7. Implementing black hole as efficient power plant

    CERN Document Server

    Wei, Shao-Wen

    2016-01-01

    Treating the black hole molecules as working substance and considering its phase structure, we study the black hole heat engine by a charged anti-de Sitter black hole. In the reduced temperature-entropy chart, it is found that the work, heat, and efficiency of the engine are independent of the black hole charge. Applying the Rankine cycle with or without a back pressure mechanism to the black hole heat engine, the efficiency is numerically solved. The result shows that the black hole engine working along the Rankine cycle with a back pressure mechanism has a higher efficiency. This provides a novel and efficient mechanism to produce the useful mechanical work with black hole, and such heat engine may act as a possible energy source for the high energy astrophysical phenomena near the black hole.

  8. Astronomy: Intermediate-mass black hole found

    Science.gov (United States)

    Gültekin, Kayhan

    2017-02-01

    The existence of medium-sized black holes has long been debated. Such an object has now been discovered in the centre of a dense cluster of stars, potentially enhancing our understanding of all black holes. See Letter p.203

  9. Regular Black Holes with Cosmological Constant

    Institute of Scientific and Technical Information of China (English)

    MO Wen-Juan; CAI Rong-Gen; SU Ru-Keng

    2006-01-01

    We present a class of regular black holes with cosmological constant Λ in nonlinear electrodynamics. Instead of usual singularity behind black hole horizon, all fields and curvature invariants are regular everywhere for the regular black holes. Through gauge invariant approach, the linearly dynamical stability of the regular black hole is studied. In odd-parity sector, we find that the Λ term does not appear in the master equations of perturbations, which shows that the regular black hole is stable under odd-parity perturbations. On the other hand, for the even-parity sector, the master equations are more complicated than the case without the cosmological constant. We obtain the sufficient conditions for stability of the regular black hole. We also investigate the thermodynamic properties of the regular black hole, and find that those thermodynamic quantities do not satisfy the differential form of first law of black hole thermodynamics. The reason for violating the first law is revealed.

  10. Biochemical compositional and technological characterizations of black and white myrtle ( Myrtus communis L.) fruits.

    Science.gov (United States)

    Hacıseferoğulları, Haydar; Ozcan, Mehmet Musa; Arslan, Derya; Unver, Ahmet

    2012-02-01

    Biochemical and technological properties were determined in developing Myrtus communis L. fruits (myrtle) from Mersin to investigate potential uses. Completely ripe black and white fruits contained ash, crude protein, crude oil, water- and alcohol soluble extracts, tartaric, malic and citric acids, and minerals including Ca, K, P, Mg and Na. Proximate compounds (%) for black and white fruits were: 7.47 and 6.36 protein, 3.487 and 3.453 oil, 3.02 and 2.30 ash, 24.28 and 26.09 dry matter, respectively. Fruits were found to be rich in some minerals such as Ca (6719.88 mg/kg and 4676.14 mg/kg), K (22647.78 mg/kg and 18339.84 mg/kg), Mg (2145.19 mg/kg and 1408.88 mg/kg), Na (3336.16 mg/kg and 2976.59 mg/kg) and P (4336.07 mg/kg and 3927.4 mg/kg). Also, physical properties such as length (14.94 mm and 13.64 mm), mass (0.94 g and 0.94 g), geometric mean diameter (12.73 mm and 12.31 mm), sphericity (0.85 and 0.90), diameter (11.76 and 11.70), projected area (1.48 cm(2) and 1.65 cm(2)), kernel density (757.47 kg/m(3)and 752.09 kg/m(3)), porosity (41.41% and 39.05%), bulk density (426.50 kg/m(3) and 431.05 kg/m(3)), terminal velocity (8.42 m/s and 8.49 m/s), volume (1.32 mm(3) and 1.35 mm(3)), repture strenth (1.77 N and 2.06 N), static (0.26-0.33 and 0.20-0.28) and dynamic coefficient (0.22-0.29 and 0.17-0.24) of friction of black myrtle and white myrtle fruits species were measured at 75.72% and 73.91% moisture content levels, respectively. These results show that both myrtle fruits may be useful for the evaluation of dietary information in important food crops.

  11. "No Cosby Show": Single Black Mother Homes and How Black Men Build Romantic Relationships

    Science.gov (United States)

    Moore, Maia Niguel

    2016-01-01

    This qualitative study explored the lives of 11 Black men to better understand how Black men who were raised in single Black mother homes build romantic relationships with Black women. One focus group and a series of individual in-person interviews were conducted with the participants who ranged between 23 and 43 years of age. Participants were…

  12. Black Boundary Lines: Race, Class and Gender among Black Undergraduate Students

    Science.gov (United States)

    Morales, Erica Marie

    2012-01-01

    Intra-group differences among Black undergraduate students remain understudied. To gain a more nuanced understanding of Black student life, we must examine how other social locations, like gender and class, connect to the racialized experiences of Black students. This dissertation argues that for Black students, class and gender, along with race,…

  13. Black Studies, Rap and the Academy. Black Literature and Culture Series.

    Science.gov (United States)

    Baker, Houston A., Jr.

    The relationships among Black Studies as an intellectual discipline and rap music are explored. It is argued that black urban culture has provided much of the impetus for Black Studies, and that the academy and those involved in the black studies discipline should feel a responsibility to take rap music seriously as the expression of urban youth,…

  14. The case for artificial black holes.

    Science.gov (United States)

    Leonhardt, Ulf; Philbin, Thomas G

    2008-08-28

    The event horizon is predicted to generate particles from the quantum vacuum, an effect that bridges three areas of physics--general relativity, quantum mechanics and thermodynamics. The quantum radiation of real black holes is too feeble to be detectable, but black-hole analogues may probe several aspects of quantum black holes. In this paper, we explain in simple terms some of the motivations behind the study of artificial black holes.

  15. Black humor in O.Henry's novels

    Institute of Scientific and Technical Information of China (English)

    冯静楠

    2013-01-01

      Black humor is a kind of literary style rose in American and O .Henry's novels used it to express the satire to society and show the sympathy to the lower class .The most typical works contain black humor two are The Cop and the Anthem and The Gift of the Magi.By using black humor, he created his unique endings .This article is trying to analysis the use of black humor in his novels and the effect.

  16. Shapes and Positions of Black Hole Shadows in Accretion Disks and Spin Parameters of Black Holes

    OpenAIRE

    Takahashi, Rohta

    2004-01-01

    Can we determine a spin parameter of a black hole by observation of a black hole shadow in an accretion disk? In order to answer this question, we make a qualitative analysis and a quantitative analysis of a shape and a position of a black hole shadow casted by a rotating black hole on an optically thick accretion disk and its dependence on an angular momentum of a black hole. We have found black hole shadows with a quite similar size and a shape for largely different black hole spin paramete...

  17. A note on the black hole remnant

    OpenAIRE

    Xiang, Li

    2006-01-01

    Analyzing the tunneling probability of a Schwarzschild black hole with a negative log-area correction to Bekenstein-Hawking entropy, I argue that this correction may be closely related to a black hole remnant. The value for the minimal black hole mass is also discussed.

  18. 5D Black Holes and Matrix Strings

    CERN Document Server

    Dijkgraaf, R; Verlinde, Herman L

    1997-01-01

    We derive the world-volume theory, the (non)-extremal entropy and background geometry of black holes and black strings constructed out of the NS IIA fivebrane within the framework of matrix theory. The CFT description of strings propagating in the black hole geometry arises as an effective field theory.

  19. 5D black holes and matrix strings

    Energy Technology Data Exchange (ETDEWEB)

    Dijkgraaf, R. [Amsterdam Univ. (Netherlands). Dept. of Mathematics; Verlinde, E. [TH-Division, CERN, CH-1211 Geneva 23 (Switzerland)]|[Institute for Theoretical Physics, University of Utrecht, 3508 TA Utrecht (Netherlands); Verlinde, H. [Institute for Theoretical Physics, University of Amsterdam, 1018 XE Amsterdam (Netherlands)

    1997-11-24

    We derive the world-volume theory, the (non)-extremal entropy and background geometry of black holes and black strings constructed out of the NS IIA 5-brane within the framework of matrix theory. The CFT description of strings propagating in the black hole geometry arises as an effective field theory. (orig.). 38 refs.

  20. 5D black holes and matrix strings

    Science.gov (United States)

    Dijkgraaf, Robbert; Verlinde, Erik; Verlinde, Herman

    1997-02-01

    We derive the world-volume theory, the (non)-extremal entropy and background geometry of black holes and black strings constructed out of the NS IIA 5-brane within the framework of matrix theory. The CFT description of strings propagating in the black hole geometry arises as an effective field theory.

  1. Signatures of black holes at the LHC

    Science.gov (United States)

    Cavaglià, Marco; Godang, Romulus; Cremaldi, Lucien M.; Summers, Donald J.

    2007-06-01

    Signatures of black hole events at CERN's Large Hadron Collider are discussed. Event simulations are carried out with the Fortran Monte Carlo generator CATFISH. Inelasticity effects, exact field emissivities, color and charge conservation, corrections to semiclassical black hole evaporation, gravitational energy loss at formation and possibility of a black hole remnant are included in the analysis.

  2. Signatures of black holes at the LHC

    CERN Document Server

    Cavaglia, Marco; Cremaldi, Lucien M; Summers, Donald J

    2007-01-01

    Signatures of black hole events at CERN's Large Hadron Collider are discussed. Event simulations are carried out with the Fortran Monte Carlo generator CATFISH. Inelasticity effects, exact field emissivities, color and charge conservation, corrections to semiclassical black hole evaporation, gravitational energy loss at formation and possibility of a black hole remnant are included in the analysis.

  3. Rising Expectations, Black Anger, and the Future

    Science.gov (United States)

    Cogdell, Roy T.; McLemore, William P.

    1977-01-01

    The societal paradox of abundant opportunities and numerous constraints affects black people's expectations, frustrations, and anger. Specific questions that this paper examines are: What are some possible causes of anger? How have black people reacted to anger-provoking situations? And what are future prospects for black people? (Author/JM)

  4. Event horizons of two Schwarzchild black holes

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, N.T.

    1988-06-01

    The problem of two Schwarzchild black holes, one much smaller than the other, is investigated by an approximate analytic method. The critical separation between the black holes at which their event horizons join is found for two cases, (2) time-symmetric initial data, and (b) the small black hole falls from rest at infinity.

  5. Resource Letter BH-1: Black Holes.

    Science.gov (United States)

    Detweiler, Steven

    1981-01-01

    Lists resources on black holes, including: (1) articles of historical interest; (2) books and journal articles on elementary expositions; (3) elementary and advanced textbooks; and (4) research articles on analytic structure of black holes, black hole dynamics, and astrophysical processes. (SK)

  6. Dumb holes: analogues for black holes.

    Science.gov (United States)

    Unruh, W G

    2008-08-28

    The use of sonic analogues to black and white holes, called dumb or deaf holes, to understand the particle production by black holes is reviewed. The results suggest that the black hole particle production is a low-frequency and low-wavenumber process.

  7. Extremal black holes in N=2 supergravity

    NARCIS (Netherlands)

    Katmadas, S.

    2011-01-01

    An explanation for the entropy of black holes has been an outstanding problem in recent decades. A special case where this is possible is that of extremal black holes in N=2 supergravity in four and five dimensions. The best developed case is for black holes preserving some supersymmetry (BPS), whic

  8. Compensating Scientism through "The Black Hole."

    Science.gov (United States)

    Roth, Lane

    The focal image of the film "The Black Hole" functions as a visual metaphor for the sacred, order, unity, and eternal time. The black hole is a symbol that unites the antinomic pairs of conscious/unconscious, water/fire, immersion/emersion, death/rebirth, and hell/heaven. The black hole is further associated with the quest for…

  9. A Black Hole in Our Galactic Center

    Science.gov (United States)

    Ruiz, Michael J.

    2008-01-01

    An introductory approach to black holes is presented along with astronomical observational data pertaining to the presence of a supermassive black hole at the center of our galaxy. Concepts of conservation of energy and Kepler's third law are employed so students can apply formulas from their physics class to determine the mass of the black hole…

  10. The Institutional Decimation of Black American Males.

    Science.gov (United States)

    Stewart, James B.; Scott, Joseph W.

    1978-01-01

    In 1970, there were 85 Black men for every 100 Black women in major American cities. Factors which produced this imbalance in the sex ratio of Blacks include educational, health care, public assistance, and penal correction systems, labor market mechanisms, and the military. (Author/MC)

  11. On Quantum Contributions to Black Hole Growth

    NARCIS (Netherlands)

    Spaans, M.

    2013-01-01

    The effects of Wheeler’s quantum foam on black hole growth are explored from an astrophysical per- spective. Quantum fluctuations in the form of mini (10−5 g) black holes can couple to macroscopic black holes and allow the latter to grow exponentially in mass on a time scale of 109 years. Consequent

  12. Micro black holes in the laboratory

    CERN Document Server

    Bleicher, Marcus; Sprenger, Martin; Winstanley, Elizabeth

    2011-01-01

    The possibility of creating microscopic black holes is one of the most exciting predictions for the LHC, with potentially major consequences for our current understanding of physics. We briefly review the theoretical motivation for micro black hole production, and our understanding of their subsequent evolution. Recent work on modelling the radiation from quantum-gravity-corrected black holes is also discussed.

  13. The Traditionally Black Colleges. 1966-1972.

    Science.gov (United States)

    Wright, Stephen J.

    This document reviews the literature concerning traditionally black colleges. Emphasis is placed on history, governance and administration, teaching and educational programs, facilities, financial problems and support, students, the black university, and the future and raison d'etre for black colleges. An extensive bibliography is included. (MJM)

  14. Black Frontier Settlements in Spanish Colonial Florida.

    Science.gov (United States)

    Landers, Jane

    1988-01-01

    Addresses the much neglected area of Black frontier experience in the Spanish colonies. Concentrates on the role played by Black settlers and one Black township in defending the Spanish frontier in colonial Florida against the threat of growing English settlements to the north. Provides an introduction to the 18th century Southeastern Spanish…

  15. Charged Black Holes in New Massive Gravity

    OpenAIRE

    Ghodsi, Ahmad; Moghadassi, Mohammad

    2010-01-01

    We construct charged black hole solutions to three-dimensional New Massive Gravity (NMG), by adding electromagnetic Maxwell and Chern-Simons actions. We find charged black holes in the form of warped AdS_3 and "log" solutions in specific critical point. The entropy, mass and angular momentum of these black holes are computed.

  16. The fuzzball proposal for black holes

    NARCIS (Netherlands)

    Skenderis, K.; Taylor, M.

    2008-01-01

    The fuzzball proposal states that associated with a black hole of entropy S, there are expS horizon-free non-singular solutions that asymptotically look like the black hole but generically differ from the black hole up to the horizon scale. These solutions, the fuzzballs, are considered to be the bl

  17. Compensating Scientism through "The Black Hole."

    Science.gov (United States)

    Roth, Lane

    The focal image of the film "The Black Hole" functions as a visual metaphor for the sacred, order, unity, and eternal time. The black hole is a symbol that unites the antinomic pairs of conscious/unconscious, water/fire, immersion/emersion, death/rebirth, and hell/heaven. The black hole is further associated with the quest for transcendent…

  18. Electroelasticity of Charged Black Branes

    CERN Document Server

    Armas, Jay; Obers, Niels A

    2013-01-01

    We present the first order corrected dynamics of fluid branes carrying higher-form charge by obtaining the general form of their equations of motion to pole-dipole order. Assuming linear response theory, we characterize the corresponding effective theory of stationary bent charged (an)isotropic fluid branes in terms of two sets of response coefficients, the Young modulus and the piezoelectric moduli. We subsequently find large classes of examples in gravity of this effective theory, by constructing stationary strained charged black brane solutions to first order in a derivative expansion. Using solution generating techniques and bent neutral black branes as a seed solution, we obtain a class of charged black brane geometries carrying smeared Maxwell charge in Einstein-Maxwell-dilaton gravity. In the specific case of ten-dimensional space-time we furthermore use T-duality to generate bent black branes with higher-form charge, including smeared D-branes of type II string theory. By subsequently measuring the be...

  19. Black English in New York.

    Science.gov (United States)

    Dillard, J. L.

    1971-01-01

    Black English has existed for a considerable length of time in the North as well as in the South. West African slaves who came to New York in 1625 found a contact language useful and mandatory in order to function in the slave community. The earliest slaves in the New York area may have used Pidgin English, Pidgin Portuguese, or Pidgin French…

  20. [Nuptiality among Brazil's black population].

    Science.gov (United States)

    Berquo, E

    1987-08-01

    Data from a three percent sample of the 1980 census of Brazil are used to analyze nuptiality trends by ethnic group. The focus is on the homogamy of marriage by color and age and on the marriage patterns of the black population.

  1. From Pinholes to Black Holes

    Energy Technology Data Exchange (ETDEWEB)

    Fenimore, Edward E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-10-06

    Pinhole photography has made major contributions to astrophysics through the use of “coded apertures”. Coded apertures were instrumental in locating gamma-ray bursts and proving that they originate in faraway galaxies, some from the birth of black holes from the first stars that formed just after the big bang.

  2. 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…

  3. Gravitational Collapse and Black Holes

    Science.gov (United States)

    Ryder, Lewis

    1973-01-01

    The newest and most exotic manner in which stars die is investigated. A brief outline is presented, along with a discussion of the role supernova play, followed by a description of how the black holes originate, exist, and how they might be detected. (DF)

  4. Black yeasts in cold habitats

    NARCIS (Netherlands)

    Selbmann, L.; de Hoog, G.S.; Zucconi, L.; Isola, D.; Onofri, S.; Buzzini, B.; Margesin, E.

    2014-01-01

    Black yeasts have already been known since the end of the nineteenth century, but for a number of reasons, only few workers were familiar with them. That was since recently, until the wealth of biodiversity, stunning ecologies and potential applications have become apparent. Some remote and extreme

  5. The Black- White Earnings Gap

    Science.gov (United States)

    Christensen, Sandra; Bernard, Keith

    1974-01-01

    Using projected labor force data (race, sex, and education) nondiscriminatory and discriminatory black-white occupational patterns and earnings ratios are defined to the year 2000. Rather than realistic estimates, the projections are designed as standards to measure progress in eliminating racial discrimination in the labor market. (EA)

  6. Body Image Satisfaction among Blacks

    Science.gov (United States)

    Gustat, Jeanette; Carton, Thomas W.; Shahien, Amir A.; Andersen, Lori

    2017-01-01

    Satisfaction with body image is a factor related to health outcomes. The purpose of this study is to examine the relationship between body image satisfaction and body size perception in an urban, Black community sample in New Orleans, Louisiana. Only 42.2% of respondents were satisfied with their body image and 44.1% correctly perceived their body…

  7. Black, Dry, Sick, and Fat

    DEFF Research Database (Denmark)

    Levisen, Carsten

    2018-01-01

    This paper explores sort humor ‘black humour’, a key concept in Danish conversational humour. Sort forms part of larger class of Danish synaesthetic humour metaphors that includes other categories such as tør ‘dry’, syg ‘sick’, and fed ‘fat’. Taking an ethnopragmatic perspective on humour discour...

  8. Black Hawkid harjutasid Pakri poolsaarel

    Index Scriptorium Estoniae

    2014-01-01

    USA 173. õhudessantbrigaadi Eestis viibiv kompanii ja Scoutspataljoni C-kompanii jalaväerühma kaitseväelased alustasid eile ühisõppust, mille käigus harjutatakse kahe Black Hawk UH-60 helikopteriga nelja Pakri poolsaarel asuva õppeobjekti ründamist

  9. Black Holes and Exotic Spinors

    Directory of Open Access Journals (Sweden)

    J. M. Hoff da Silva

    2016-05-01

    Full Text Available Exotic spin structures are non-trivial liftings, of the orthogonal bundle to the spin bundle, on orientable manifolds that admit spin structures according to the celebrated Geroch theorem. Exotic spin structures play a role of paramount importance in different areas of physics, from quantum field theory, in particular at Planck length scales, to gravity, and in cosmological scales. Here, we introduce an in-depth panorama in this field, providing black hole physics as the fount of spacetime exoticness. Black holes are then studied as the generators of a non-trivial topology that also can correspond to some inequivalent spin structure. Moreover, we investigate exotic spinor fields in this context and the way exotic spinor fields branch new physics. We also calculate the tunneling probability of exotic fermions across a Kerr-Sen black hole, showing that the exotic term does affect the tunneling probability, altering the black hole evaporation rate. Finally we show that it complies with the Hawking temperature universal law.

  10. Android for the Beaglebone Black

    CERN Document Server

    Henderson, Andrew

    2015-01-01

    If you are an Android app developer who wants to experiment with the hardware capabilities of the BeagleBone Black platform, then this book is ideal for you. You are expected to have basic knowledge of developing Android apps but no prior hardware experience is required.

  11. Force-feeding Black Holes

    CERN Document Server

    Begelman, Mitchell C

    2012-01-01

    We propose that the growth of supermassive black holes is associated mainly with brief episodes of highly super-Eddington infall of gas ("hyperaccretion"). This gas is not swallowed in real time, but forms an envelope of matter around the black hole that can be swallowed gradually, over a much longer timescale. However, only a small fraction of the black hole mass can be stored in the envelope at any one time. We argue that any infalling matter above a few per cent of the hole's mass is ejected as a result of the plunge in opacity at temperatures below a few thousand degrees K, corresponding to the Hayashi track. The speed of ejection of this matter, compared to the velocity dispersion (sigma) of the host galaxy's core, determines whether the ejected matter is lost forever or returns eventually to rejoin the envelope, from which it can be ultimately accreted. The threshold between matter recycling and permanent loss defines a relationship between the maximum black hole mass and sigma that resembles the empiri...

  12. Black Physical Educators and Utilitarianism.

    Science.gov (United States)

    Coursey, Leon N.

    The contributions of black professional personnel to the field of physical education are enumerated and described. The careers of Anita J. Turner, Edwin B. Henderson, and Albert J. Overly in particular are examined. The ability of a minority group to provide significant leadership in an educational field is discussed, and the challenge still…

  13. Graduate Opportunities for Black Students.

    Science.gov (United States)

    Paynter, Julie, Ed.

    This document catalogues graduate opportunities specifically for black students in 1969-70 at 42 universities, 96 additional graduate departments (social sciences, natural sciences, mathematics, and humanities), and 111 additional professional schools (particularly social work, education, law, medicine, theology, business, and library science).…

  14. Information retrieval from black holes

    CERN Document Server

    Lochan, Kinjalk; Padmanabhan, T

    2016-01-01

    It is generally believed that, when matter collapses to form a black hole, the complete information about the initial state of the matter cannot be retrieved by future asymptotic observers, through local measurements. This is contrary to the expectation from a unitary evolution in quantum theory and leads to (a version of) the black hole information paradox. Classically, nothing else, apart from mass, charge and angular momentum is expected to be revealed to such asymptotic observers after the formation of a black hole. Semi-classically, black holes evaporate after their formation through the Hawking radiation. The dominant part of the radiation is expected to be thermal and hence one cannot know anything about the initial data from the resultant radiation. However, there can be sources of distortions which make the radiation non-thermal. Although the distortions are not strong enough to make the evolution unitary, these distortions carry some part of information regarding the in-state. In this work, we show ...

  15. Information retrieval from black holes

    Science.gov (United States)

    Lochan, Kinjalk; Chakraborty, Sumanta; Padmanabhan, T.

    2016-08-01

    It is generally believed that, when matter collapses to form a black hole, the complete information about the initial state of the matter cannot be retrieved by future asymptotic observers, through local measurements. This is contrary to the expectation from a unitary evolution in quantum theory and leads to (a version of) the black hole information paradox. Classically, nothing else, apart from mass, charge, and angular momentum is expected to be revealed to such asymptotic observers after the formation of a black hole. Semiclassically, black holes evaporate after their formation through the Hawking radiation. The dominant part of the radiation is expected to be thermal and hence one cannot know anything about the initial data from the resultant radiation. However, there can be sources of distortions which make the radiation nonthermal. Although the distortions are not strong enough to make the evolution unitary, these distortions carry some part of information regarding the in-state. In this work, we show how one can decipher the information about the in-state of the field from these distortions. We show that the distortions of a particular kind—which we call nonvacuum distortions—can be used to fully reconstruct the initial data. The asymptotic observer can do this operationally by measuring certain well-defined observables of the quantum field at late times. We demonstrate that a general class of in-states encode all their information content in the correlation of late time out-going modes. Further, using a 1 +1 dimensional dilatonic black hole model to accommodate backreaction self-consistently, we show that observers can also infer and track the information content about the initial data, during the course of evaporation, unambiguously. Implications of such information extraction are discussed.

  16. Características de doce em massa de umbu verde e maduro e aceitação pelos consumidores Characteristics of green and ripe umbu marmalades and acceptance by consumers

    Directory of Open Access Journals (Sweden)

    Maria Lúcia Almeida Martins

    2007-09-01

    Full Text Available O objetivo deste trabalho foi avaliar formulações de doces, em massa de umbu verde e maduro, quanto às características físico-químicas e físicas, e quanto à aceitação pelos consumidores residentes no Rio de Janeiro. Quatro formulações de doces foram processadas para polpa de umbu verde: F1, 0,3% de goma xantana; F2, 5% de xarope de glicose e 0,3% de goma xantana; F3, 0,5% de amido modificado; F4, 5% de xarope de glicose e 0,5% de amido modificado; e quatro formulações para polpa de umbu maduro: F1, apenas correção de pH; F2, 0,5% de pectina; F3, 0,3% de goma xantana; F4, 5% de xarope de glicose e 0,5% de amido modificado. Foram avaliadas as seguintes características físico-químicas e físicas: sólidos solúveis, acidez titulável, pH, açúcares redutores e não redutores, atividade de água, cor, firmeza e adesividade. Cinqüenta e seis consumidores avaliaram as formulações, por meio de escala hedônica estruturada de nove pontos. As formulações F2 apresentaram maior firmeza. Os consumidores atribuíram notas superiores a seis na escala utilizada, para todas as formulações, o que indica aceitação dos produtos.The objective of this work was to evaluate green and ripe umbu marmalade formulations, in relation to physicochemical and physical characteristics, and regarding Rio de Janeiro consumers' acceptance. Four marmalade formulations were processed for green umbu pulp: F1, 0.3% xanthan gum; F2, 5% glucose syrup and 0.3% xanthan gum; F3, 0.5% modified starch; F4, 5% glucose syrup and 0.5% modified starch; and four formulations for ripe umbu pulp: F1, only pH correction; F2, 0.5% pectin; F3, 0.3% xanthan gum; F4, 5% glucose syrup and 0.5% modified starch. The physicochemical and physical characteristics evaluated were: soluble solids, titrable acidity, pH, reducing and nonreducing sugars, water activity, color, firmness and adhesiveness. Fifty-six consumers evaluated the formulations, using nine-point structured hedonic

  17. 采收期对南果梨完熟果实香气组成的影响%Effect of Harvest Time on Aromatic Components of Fully Ripe Nanguo Pear Fruits

    Institute of Scientific and Technical Information of China (English)

    秦改花; 黄文江; 张虎平; 陶书田; 李俊才; 张绍铃

    2012-01-01

    The aroma composition of fully ripe Nanguo pear fruits harvested at different times were determined by headspacesolid phase microextraction gas chromatogaphy-mass spectrometry(HS-SPME-GC-MS).The results showed that the composition and contents of aromatic compounds in fruits harvested at different times were different,especially for characteristic aroma.Early harvested fruits had characteristic aroma components including ethyl butyrate,2-methyl ethyl butyrate,ethyl hexanoate,hexyl acetate,hexanal and decanal;in contrast,late harvested fruits had butyl acetate and 2-hexenal as additional characteristic aroma components.Moreover,late harvested fruits had strong fruity aroma,however,early harvested fruits had fruity aroma coupled with little grassy aroma.%以不同采收期的南果梨为材料,用顶空固相微萃取(headspace-solid phase microextraction,HS-SPME)结合气质联用(gas chromatogaphy-mass spectrometry,GC-MS)技术对完熟果实的香气进行研究。结果表明,不同采收期果实的香气组成和含量均有一定差异,尤以特征香气的差别较大。早采果实的特征香气主要有丁酸乙酯、2-甲基-丁酸乙酯、己酸乙酯、乙酸己酯、己醛和癸醛,而晚采果实比早采收果实多了乙酸丁酯和2-己烯醛两种特征香气。晚采果实表现出较浓的果香味,而早采果实中除果香味外,还有一定的青香味。

  18. Dyonic Non-Abelian Black Holes

    CERN Document Server

    Brihaye, Y; Kunz, J; Tell, N

    1999-01-01

    We study static spherically symmetric dyonic black holes in Einstein-Yang-Mills-Higgs theory. As for the magnetic non-abelian black holes, the domain of existence of the dyonic non-abelian black holes is limited with respect to the horizon radius and the dimensionless coupling constant $\\alpha$, which is proportional to the ratio of vector meson mass and Planck mass. At a certain critical value of this coupling constant, $\\hat \\alpha$, the maximal horizon radius is attained. We derive analytically a relation between $\\hat numerically. Besides the fundamental dyonic non-abelian black holes, we study radially excited dyonic non-abelian black holes and globally regular gravitating dyons.

  19. Black Ring with a Positive Cosmological Constant

    CERN Document Server

    Chu, C S; Chu, Chong-Sun; Dai, Shou-Huang

    2007-01-01

    We construct a black ring with a cosmological constant in the five dimensional N=4 de Sitter supergravity theory. The black ring preserves half of the de Sitter supersymmetries. Unlike the flat case, this black ring is not rotating and the stability against gravitational self-attraction is balanced by the cosmological repulsion due to the cosmological constant. The black ring carries a dipole charge and this charge contributes to the first law of thermodynamics. The black ring has an entropy and mass which conform to the entropic N-bound proposal and the maximal mass conjecture.

  20. Black Hole Decay as Geodesic Motion

    CERN Document Server

    Sen-Gupta, K; 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 decay rate is shown to be correctly described by geodesic motion in the space of black hole masses. This provides a novel geometric interpretation for the decay of black holes. We also show that the near-horizon conformal symmetry predicts a precise correction term to the usual expression for the decay rate of black holes. The results obtained here are a consequence of the holographic nature of the system.

  1. An Optical Analog of a Black Holes

    CERN Document Server

    Royston, A; Royston, Andrew; Gass, Richard

    2002-01-01

    Using media with extremely low group velocities one can create an optical analog of a curved space-time. Leonhardt and Piwnicki have proposed that a vortex flow will act as an optical black hole. We show that although the Leonhardt - Piwnicki flow has an orbit of no return and an infinite red-shift surface, it is not a true black hole since it lacks a null hypersurface. However a radial flow will produce a true optical black hole that has a Hawking temperature and obeys the first law of black hole mechanics. By combining the Leonhardt - Piwnicki flow with a radial flow we obtain the analog of the Kerr black hole.

  2. A Black feminist approach to nursing research.

    Science.gov (United States)

    Barbee, E L

    1994-10-01

    Despite the presence of a body of Black feminist literature, the growing body of nursing literature on feminism and the feminist approach to research remains narrowly focused on White feminist concerns. By essentially ignoring the realities of Black women, nursing has reproduced the errors of previous White feminists. This article demonstrates the relevance of the Black feminist approach to nursing by applying it in combination with general feminist research principles and anthropological theory in research concerned with low-income Black women's experiences with dysphoria and depression. The findings of the research suggest that a combination approach more clearly illuminates how context effects dysphoria in poor Black women.

  3. Black Hole Radiation and Volume Statistical Entropy

    CERN Document Server

    Rabinowitz, M

    2005-01-01

    The simplest possible equations for Hawking radiation, and other black hole radiated power is derived in terms of black hole density. Black hole density also leads to the simplest possible model of a gas of elementary constituents confined inside a gravitational bottle of Schwarzchild radius at tremendous pressure, which yields identically the same functional dependence as the traditional black hole entropy. Variations of Sbh are can be obtained which depend on the occupancy of phase space cells. A relation is derived between the constituent momenta and the black hole radius RH

  4. Black holes under external influence

    Indian Academy of Sciences (India)

    Jiří Bičák

    2000-10-01

    The work on black holes immersed in external fields is reviewed in both test-field approximation and within exact solutions. In particular we pay attention to the effect of the expulsion of the flux of external fields across charged and rotating black holes which are approaching extremal states. Recently this effect has been shown to occur for black hole solutions in string theory. We also discuss black holes surrounded by rings and disks and rotating black holes accelerated by strings.

  5. Black Holes Shed Light on Galaxy Formation

    Science.gov (United States)

    2000-01-01

    This videotape is comprised of several segments of animations on black holes and galaxy formation, and several segments of an interview with Dr. John Kormendy. The animation segments are: (1) a super massive black hole, (2) Centarus A active black hole found in a collision, (3) galaxy NGC-4261 (active black hole and jet model), (4) galaxy M-32 (orbits of stars are effected by the gravity of the black hole), (5) galaxy M-37 (motion of stars increases as mass of black hole increases), (6) Birth of active galactic nuclei, (7) the collision of two galaxy leads to merger of the black holes, (8) Centarus A and simulation of the collision of 2 galaxies. There are also several segments of an interview with John Kormendy. In these segments he discusses the two most important aspects of his recent black hole work: (1) the correlations between galaxies speed and the mass of the black holes, and (2) the existence of black holes and galactic formation. He also discusses the importance of the Hubble Space Telescope and the Space Telescope Imaging Spectrograph to the study of black holes. He also shows the methodology of processing images from the spectrograph in his office.

  6. Quasistars: Accreting black holes inside massive envelopes

    CERN Document Server

    Begelman, Mitchell C; Armitage, Philip J

    2007-01-01

    We study the structure and evolution of "quasistars," accreting black holes embedded within massive hydrostatic gaseous envelopes. These configurations may model the early growth of supermassive black hole seeds. The accretion rate onto the black hole adjusts so that the luminosity carried by the convective envelope equals the Eddington limit for the total mass. This greatly exceeds the Eddington limit for the black hole mass alone, leading to rapid growth of the black hole. We use analytic models and numerical stellar structure calculations to study the structure and evolution of quasistars. We derive analytically the scaling of the photospheric temperature with the black hole mass and envelope mass, and show that it decreases with time as the black hole mass increases. Once the photospheric temperature becomes lower than 10000 K, the photospheric opacity drops precipitously and the photospheric temperature hits a limiting value, analogous to the Hayashi track for red giants and protostars, below which no hy...

  7. From Schwinger Balls to Black Holes

    CERN Document Server

    Allahbakhshi, Davood

    2016-01-01

    We have shown intriguing similarities between Schwinger balls and black holes. By considering black hole as a gravitational Schwinger ball, we have derived the Bekenstein-Hawking entropy and the first law of black hole thermodynamics as a direct result of the inverse area dependence of the gravitational force. It is also shown that the Planck length is nothing but the gravitational Schwinger length. The relation between the mass and the radius of the black hole is derived by considering the black hole as a Schwinger ball of gravitons. We show how the evolution of the entanglement entropy of the black hole, as Page introduced many years ago, can be obtained by including gravitons in the black hole's evaporation process and using a deformed EPR mechanism. Also this deformed EPR mechanism can solve the information paradox. We show how naive simultaneous usage of Page's argument and equivalence principle leads to firewall problem.

  8. Black supernovae and black holes in non-local gravity

    CERN Document Server

    Bambi, Cosimo; Modesto, Leonardo

    2016-01-01

    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 certai...

  9. Hawking Radiation from Regular Black Hole as a Possible Probe for Black Hole Interior Structure

    CERN Document Server

    Deng, Yanbin

    2016-01-01

    The notion of the black hole singularity and the proof of the singularity theorem in general relativity were considered great successes in gravitational physics. On the other hand they also presented deep puzzles to physicists. Conceptual challenges were set up by the intractability of the singularity. The existence of black hole horizons which cover up the interior, including the singularity of the black hole from outside observers, builds an information curtain, further hindering physicists from understanding the nature of the singularity and the interior structure of black holes. The regular black hole is a concept produced out of multiple attempts to establish a tractable and understandable interior structure for black hole and to avoid the singularity inside the black hole body. A method is needed to check the correctness of the new constructions of black holes. After studying the Hawking radiation by fermion tunnelling from one type of regular black hole, structure dependent results were obtained. The r...

  10. 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.

  11. Black Holes with Proca Hair

    CERN Document Server

    Fan, Zhong-Ying

    2016-01-01

    In this paper, we consider Einstein gravity coupled to a Proca field, either minimally or non-minimally, together with a vector potential of the type $V=2\\Lambda_0+ m^2 A^2/2 + \\gamma_4 A^4$. For a simpler non-minimally coupled theory with $\\Lambda_0=m=\\gamma_4=0$, we obtain both extremal and non-extremal black hole solutions that are asymptotic to Minkowski space-times. We study the global properties of the solutions and derive the first law of thermodynamics using Wald formalism. We find that the thermodynamical first laws of the extremal black holes are modified by a one form associated with the Proca. In particular, due to the existence of the non-minimal coupling, the Proca forms thermodynamic conjugates with the graviton mode and partly contributes to the one form modifying the first laws. For a minimally coupled theory with $\\Lambda_0\

  12. "Twisted" black holes are unphysical

    CERN Document Server

    Gray, Finnian; Schuster, Sebastian; Visser, Matt

    2016-01-01

    So-called "twisted" black holes have recently been proposed by Zhang (1609.09721 [gr-qc]), and further considered by Chen and Jing (1610.00886 [gr-qc]), and more recently by Ong (1610.05757 [gr-qc]). While these spacetimes are certainly Ricci-flat, and so mathematically satisfy the vacuum Einstein equations, they are also merely minor variants on Taub--NUT spacetimes. Consequently they exhibit several unphysical features that make them quite unreasonable as realistic astrophysical objects. Specifically, these "twisted" black holes are not (globally) asymptotically flat. Furthermore, they contain closed timelike curves that are not hidden behind any event horizon --- the most obvious of these closed timelike curves are small azimuthal circles around the rotation axis, but the effect is more general. The entire region outside the horizon is infested with closed timelike curves.

  13. Black Hole with Quantum Potential

    CERN Document Server

    Ali, Ahmed Farag

    2015-01-01

    In this work, we investigate black hole (BH) physics in the context of quantum corrections. These quantum corrections were introduced recently by replacing classical geodesics with quantal (Bohmian) trajectories and hence form a quantum Raychaudhuri equation (QRE). From the QRE, we derive a modified Schwarzschild metric, and use that metric to investigate BH singularity and thermodynamics. We find that these quantum corrections change the picture of Hawking radiation greatly when the size of BH approaches the Planck scale. They prevent the BH from total evaporation, predicting the existence of a quantum BH remnant, which introduces a possible resolution for the catastrophic behavior of Hawking radiation as the BH mass approaches zero. It also ameliorates the black hole singularity and the information loss problem.

  14. Black hole with quantum potential

    Directory of Open Access Journals (Sweden)

    Ahmed Farag Ali

    2016-08-01

    Full Text Available In this work, we investigate black hole (BH physics in the context of quantum corrections. These quantum corrections were introduced recently by replacing classical geodesics with quantal (Bohmian trajectories and hence form a quantum Raychaudhuri equation (QRE. From the QRE, we derive a modified Schwarzschild metric, and use that metric to investigate BH singularity and thermodynamics. We find that these quantum corrections change the picture of Hawking radiation greatly when the size of BH approaches the Planck scale. They prevent the BH from total evaporation, predicting the existence of a quantum BH remnant, which may introduce a possible resolution for the catastrophic behavior of Hawking radiation as the BH mass approaches zero. Those corrections also turn the spacelike singularity of the black hole to be timelike, and hence this may ameliorate the information loss problem.

  15. Linezolid induced black hairy tongue

    Directory of Open Access Journals (Sweden)

    Govindan Balaji

    2014-01-01

    Full Text Available Black hairy tongue (BHT also called as lingua villosa nigra, is a self limiting benign condition characterized by hypertrophy and elongation of filiform papillae of tongue with brown or black discoloration. Smoking, poor oral hygiene, xerostomia, using peroxide containing mouth washes, substance abuse and drugs (steroids, methyldopa, olanzapine, etc are the predisposing factors. However its occurrence in relation to linezolid ingestion among south Indians has not been reported in PubMed database. Here we report a case, where significant association of linezolid intake with BHT was found in a 10-year-old boy, who was treated with tablet linezolid for post surgical infection of left side radial neck fracture. This case is reported for the rarity of occurrence with linezolid therapy. According to Naranjo adverse drug reaction (ADR causality scale, the association of BHT due to linezolid in our case was probable.

  16. Black Holes at the LHC

    CERN Document Server

    Kanti, Panagiota

    2008-01-01

    In these two lectures, we will address the topic of the creation of small black holes during particle collisions in a ground-based accelerator, such as LHC, in the context of a higher-dimensional theory. We will cover the main assumptions, criteria and estimates for their creation, and we will discuss their properties after their formation. The most important observable effect associated with their creation is likely to be the emission of Hawking radiation during their evaporation process. After presenting the mathematical formalism for its study, we will review the current results for the emission of particles both on the brane and in the bulk. We will finish with a discussion of the methodology that will be used to study these spectra, and the observable signatures that will help us identify the black-hole events.

  17. Black holes in magnetic monopoles

    Science.gov (United States)

    Lee, Kimyeong; Nair, V. P.; Weinberg, Erick J.

    1992-04-01

    We study magnetically charged classical solutions of a spontaneously broken gauge theory interacting with gravity. We show that nonsingular monopole solutions exist only if the Higgs-field vacuum expectation value v is less than or equal to a critical value vcr, which is of the order of the Planck mass. In the limiting case, the monopole becomes a black hole, with the region outside the horizon described by the critical Reissner-Nordström solution. For vsolutions which are singular at r=0, but which have this singularity hidden within a horizon. These have nontrivial matter fields outside the horizon, and may be interpreted as small black holes lying within a magnetic monopole. The nature of these solutions as a function of v and of the total mass M and their relation to the Reissner-Nordström solutions are discussed.

  18. Black Holes in Magnetic Monopoles

    CERN Document Server

    Lee, K; Weinberg, Erick J; Weinberg, Erick J.

    1992-01-01

    We study magnetically charged classical solutions of a spontaneously broken gauge theory interacting with gravity. We show that nonsingular monopole solutions exist only if the Higgs vacuum expectation value $v$ is less than or equal to a critical value $v_{cr}$, which is of the order of the Planck mass. In the limiting case the monopole becomes a black hole, with the region outside the horizon described by the critical Reissner-Nordstrom solution. For $v

  19. Extremal Black Holes as Qudits

    CERN Document Server

    Rios, Michael

    2011-01-01

    We extend the black hole/qudit correspondence by identifying five and six-dimensional 1/2-BPS black string and hole charge vectors in N=8 and N=2 magic supergravities with qubits and qutrits over composition algebras. In D=6, this is accomplished via Hopf fibrations, which map qubits over composition algebras to rank one elements of Jordan algebras of degree two. An analogous procedure maps qutrits over composition algebras to D=5 charge vectors, which are rank one elements of Jordan algebras of degree three. In both cases, the U-duality groups are interpreted as qudit SLOCC transformation groups. We provide explicit gates for such transformations and study their applications in toroidally compactified M-theory.

  20. Black hole with quantum potential

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Ahmed Farag, E-mail: ahmed.ali@fsc.bu.edu.eg [Department of Physics, Faculty of Science, Benha University, Benha 13518 (Egypt); Khalil, Mohammed M., E-mail: moh.m.khalil@gmail.com [Department of Electrical Engineering, Alexandria University, Alexandria 12544 (Egypt)

    2016-08-15

    In this work, we investigate black hole (BH) physics in the context of quantum corrections. These quantum corrections were introduced recently by replacing classical geodesics with quantal (Bohmian) trajectories and hence form a quantum Raychaudhuri equation (QRE). From the QRE, we derive a modified Schwarzschild metric, and use that metric to investigate BH singularity and thermodynamics. We find that these quantum corrections change the picture of Hawking radiation greatly when the size of BH approaches the Planck scale. They prevent the BH from total evaporation, predicting the existence of a quantum BH remnant, which may introduce a possible resolution for the catastrophic behavior of Hawking radiation as the BH mass approaches zero. Those corrections also turn the spacelike singularity of the black hole to be timelike, and hence this may ameliorate the information loss problem.

  1. Black Orpheus and Aesthetic Historicism

    Directory of Open Access Journals (Sweden)

    Marina Paola Banchetti-Robino

    2011-11-01

    Full Text Available This essay offers a novel approach for understanding the poetry of negritude and its role in the struggle for black liberation by appealing to Giambattista Vico’s insights on the historical, cultural, and myth-making function of poetry and of the mythopoetic imagination.  The essay begins with a discussion of Vico’s aesthetic historicism and of his ideas regarding the role of imagination, poetry, and myth-making and then brings these ideas to bear on the discussion of the function of negritude poetry, focusing primarily on the writings of Aimé Césaire and on Jean-Paul Sartre’s essay, Black Orpheus.

  2. Complexity, Action, and Black Holes

    CERN Document Server

    Brown, Adam; Susskind, Leonard; Swingle, Brian; Zhao, Ying

    2015-01-01

    Our earlier paper "Complexity Equals Action" conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the `Wheeler-DeWitt' patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are fastest computers in nature.

  3. Complexity, action, and black holes

    Science.gov (United States)

    Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; Swingle, Brian; Zhao, Ying

    2016-04-01

    Our earlier paper "Complexity Equals Action" conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the "Wheeler-DeWitt" patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are the fastest computers in nature.

  4. Bleaching of Black Human Hair

    Institute of Scientific and Technical Information of China (English)

    林琳

    2001-01-01

    Bleaching of black human hair has been studied systematically. On the basis of experimental data the technology of human hair bleaching through five processes was established. The optimum technology of improving the whiteness and reducing damage on fibers has been found. The technology can provide good luster,smooth handle and relatively high strength retention to human hair used for wigs or drama articles, meeting the needs of people better. Moreover, it also has important reference value to bleaching of other colored fibers.

  5. Geometric obstruction of black holes

    CERN Document Server

    Punzi, R; Wohlfarth, M N R; Punzi, Raffaele; Schuller, Frederic P.; Wohlfarth, Mattias N. R.

    2006-01-01

    We study the global structure of Lorentzian manifolds with partial sectional curvature bounds. In particular, we prove completeness theorems for homogeneous and isotropic cosmologies as well as static spherically symmetric spacetimes. The latter result is used to rigorously prove the absence of static spherically symmetric black holes in more than three dimensions. The proofs of these new results are preceded by a detailed exposition of the local aspects of sectional curvature bounds for Lorentzian manifolds, which extends and strengthens previous constructions.

  6. A Black Hole Life Preserver

    CERN Document Server

    Gott, J R; Freedman, Deborah L.

    2003-01-01

    Since no one lives forever, all a life preserver can really do is prolong life for longer than would have otherwise been the case. With this rather limited definition in mind we explore in this paper whether in principle you can take a life preserver with you to protect you (for a while at least) against the tidal forces encountered on a trip inside a black hole.

  7. Van der Waals black hole

    Directory of Open Access Journals (Sweden)

    Aruna Rajagopal

    2014-10-01

    Full Text Available In the context of extended phase space, where the negative cosmological constant is treated as a thermodynamic pressure in the first law of black hole thermodynamics, we find an asymptotically AdS metric whose thermodynamics matches exactly that of the Van der Waals fluid. We show that as a solution of Einstein's equations, the corresponding stress energy tensor obeys (at least for certain range of metric parameters all three weak, strong, and dominant energy conditions.

  8. Gayge Fields and Black Holes

    Science.gov (United States)

    Gal'Tsov, D. V.

    1987-10-01

    Exact solutions of the Einstein-Yang-Mills and Einstein-Yang-Mills-Higgs systems of equations are examined, which describe Black Holes, with gluonic and scalar hairs. A simple deduction of these equations, based on the use of the gayge symmetry is given. The transition to a nonsingular gayge for gravitating Wu - Yang monopoles, in which the singularity is headen inside the horizon, is discussed. Bibliography: 11

  9. Black Hole Thermodynamics and Electromagnetism

    CERN Document Server

    Sidharth, B G

    2005-01-01

    We show a strong parallel between the Hawking, Beckenstein black hole Thermodynamics and electromagnetism: When the gravitational coupling constant transform into the electromagnetic coupling constant, the Schwarzchild radius, the Beckenstein temperature, the Beckenstein decay time and the Planck mass transform to respectively the Compton wavelength, the Hagedorn temperature, the Compton time and a typical elementary particle mass. The reasons underlying this parallalism are then discussed in detail.

  10. Broken links and black boxes

    DEFF Research Database (Denmark)

    Sindbæk, Søren Michael

    2013-01-01

    Long-distance communication has emerged as a particular focus for archaeological exploration using network theory, analysis, and modelling. Initial attempts to adapt methods from social network analysis to archaeological data have, however, struggled to produce decisive results. This paper argues...... observable distributions and patterns of association in the archaeological record. In formal terms this is not a problem of network analysis, but network synthesis: the classic problem of cracking codes or reconstructing black-box circuits....

  11. BSW process of the slowly evaporating charged black hole

    OpenAIRE

    Wang, Liancheng; He, Feng; Fu, Xiangyun

    2015-01-01

    In this paper, we study the BSW process of the slowly evaporating charged black hole. It can be found that the BSW process will also arise near black hole horizon when the evaporation of charged black hole is very slow. But now the background black hole does not have to be an extremal black hole, and it will be approximately an extremal black hole unless it is nearly a huge stationary black hole.

  12. Black Holes and Random Matrices

    CERN Document Server

    Cotler, Jordan S; Hanada, Masanori; Polchinski, Joseph; Saad, Phil; Shenker, Stephen H; Stanford, Douglas; Streicher, Alexandre; Tezuka, Masaki

    2016-01-01

    We argue that the late time behavior of horizon fluctuations in large anti-de Sitter (AdS) black holes is governed by the random matrix dynamics characteristic of quantum chaotic systems. Our main tool is the Sachdev-Ye-Kitaev (SYK) model, which we use as a simple model of a black hole. We use an analytically continued partition function $|Z(\\beta +it)|^2$ as well as correlation functions as diagnostics. Using numerical techniques we establish random matrix behavior at late times. We determine the early time behavior exactly in a double scaling limit, giving us a plausible estimate for the crossover time to random matrix behavior. We use these ideas to formulate a conjecture about general large AdS black holes, like those dual to 4D super-Yang-Mills theory, giving a provisional estimate of the crossover time. We make some preliminary comments about challenges to understanding the late time dynamics from a bulk point of view.

  13. Black Holes as Effective Geometries

    CERN Document Server

    Balasubramanian, Vijay; El-Showk, Sheer; Messamah, Ilies

    2008-01-01

    Gravitational entropy arises in string theory via coarse graining over an underlying space of microstates. In this review we would like to address the question of how the classical black hole geometry itself arises as an effective or approximate description of a pure state, in a closed string theory, which semiclassical observers are unable to distinguish from the "naive" geometry. In cases with enough supersymmetry it has been possible to explicitly construct these microstates in spacetime, and understand how coarse-graining of non-singular, horizon-free objects can lead to an effective description as an extremal black hole. We discuss how these results arise for examples in Type II string theory on AdS_5 x S^5 and on AdS_3 x S^3 x T^4 that preserve 16 and 8 supercharges respectively. For such a picture of black holes as effective geometries to extend to cases with finite horizon area the scale of quantum effects in gravity would have to extend well beyond the vicinity of the singularities in the effective t...

  14. Hair of astrophysical black holes

    CERN Document Server

    Lyutikov, Maxim

    2012-01-01

    The "no hair" theorem is not applicable to black holes formed from collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively "frozen-in" the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes N_B = e \\Phi_\\infty /(\\pi c \\hbar), where \\Phi_\\infty is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. The black hole's magnetosphere subsequently relaxes to the split monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that...

  15. Soft Hair on Black Holes.

    Science.gov (United States)

    Hawking, Stephen W; Perry, Malcolm J; Strominger, Andrew

    2016-06-10

    It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units.

  16. Fractal black holes and information

    Energy Technology Data Exchange (ETDEWEB)

    El Naschie, M.S. [Department of Physics, University of Alexandria, Alexandria (Egypt); Department of Astrophysics, Cairo University (Egypt); Department of Physics, Mansura University (Egypt)

    2006-07-15

    If nature is fractal as it evidently is, at classical resolution and if it is suspected to also be fractal at the quantum resolution as it is now a days generally believed to be, then we must have over looked at least two points or so in our physical model building of mini black holes. To start with at such ultra high resolution, the mini black hole geometry must be a fractal. Consequently we have zero volume and only a fractal surface area. Second because we cannot take the differential limit for the -bar {sub p}{sup 2} covering the transfinite surface area, there will be many gaps between the (-bar {sub p}){sup 2} tilings. In other words we must introduce transfinite corrections to the final result. Proceeding this way the information entropy unit of a black hole should be a=I=(7+{phi}{sup 3})(10){sup -66}cm{sup 2}=7.23606799(10){sup -66}cm{sup 2}The nearest classical result to the above is that obtained by Gerard 't Hoofta=I=(0.724)(10){sup -65}cm{sup 2}The paper ends with a general discussion of E-infinity theory and its possible relation with 't Hooft's holographic principle and his gluons-quark strings.

  17. On The Black Sea Surozhian

    Science.gov (United States)

    Caraivan, Glicherie; Corneliu, Cerchia

    2016-04-01

    Some Black Sea researchers still support the idea of no other connection to the Mediterranean Sea between LGM and Karangatian Stage (Riss - Wurm). We try to clarify the source of these disagreements. C14 AMS age data (HERAS Project) made on undisturbed samples from a new Mamaia drilling hole where compared with the classical Black Sea stratigraphic schemes. A first transgressive event (Zone D) is found between 38.00 - 20.20 m depth. Zone D4 shows a fairly rapid rise of sea level, about 10 m below the present one indicating an inner shelf marine polyhaline environment. AMS age data show 14C ages between 53690 - 47359 y (MIS 1), corresponding to the "Surozhian Beds" of Popov. The "beach rock" from Zone E marks the decrease of the sea level after the maximum reached in Zone D4. Zone E mollusc shells AMS data, indicate 14C ages of 48724 - 44604 y, suggesting a long-time reworked material from the previous D4 zone sediments, and represents the beginning of the "regressive Tarkankutian" sequence.The Last Glacial Maximum (LGM) led to the retreat of the sea level down to about 100 m below the current one (27-17 ky BP), followed by an retreat of the shoreline to the present position. At the beginning of the Holocene - MIS 1 (8408-8132 cal. y BP), Black Sea brackish water level grew rapidly, up to -14 m below the present one (Zone F: 22, 57-20, 20 m). Zone F deposits could be correlated with the Bugazian strata. Then, a continuous rising of the Black Sea level is recorded up to a maximum of -2 m under the present one, about 6789 - 7063 cal. y BP, when a transgressive spurt ("Neolithic transgression") may have taken place. After that, given a weak Danubian sedimentary input, coastal erosion intensified. The coarse sandy sediments were reworked and pushed over the previous peat deposits, and suggest a classical "sedimentary regression", not a sea-level decrease. During the last 1.5 ky, sea level has risen towards the current one. Previous C14 dates from "Karangatian

  18. Soft Hair on Black Holes

    CERN Document Server

    Hawking, Stephen W; Strominger, Andrew

    2016-01-01

    It has recently been shown that BMS supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft ($i.e.$ zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This paper gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the ho...

  19. Entanglement Entropy of Black Holes

    Directory of Open Access Journals (Sweden)

    Sergey N. Solodukhin

    2011-10-01

    Full Text Available The entanglement entropy is a fundamental quantity, which characterizes the correlations between sub-systems in a larger quantum-mechanical system. For two sub-systems separated by a surface the entanglement entropy is proportional to the area of the surface and depends on the UV cutoff, which regulates the short-distance correlations. The geometrical nature of entanglement-entropy calculation is particularly intriguing when applied to black holes when the entangling surface is the black-hole horizon. I review a variety of aspects of this calculation: the useful mathematical tools such as the geometry of spaces with conical singularities and the heat kernel method, the UV divergences in the entropy and their renormalization, the logarithmic terms in the entanglement entropy in four and six dimensions and their relation to the conformal anomalies. The focus in the review is on the systematic use of the conical singularity method. The relations to other known approaches such as ’t Hooft’s brick-wall model and the Euclidean path integral in the optical metric are discussed in detail. The puzzling behavior of the entanglement entropy due to fields, which non-minimally couple to gravity, is emphasized. The holographic description of the entanglement entropy of the black-hole horizon is illustrated on the two- and four-dimensional examples. Finally, I examine the possibility to interpret the Bekenstein-Hawking entropy entirely as the entanglement entropy.

  20. Entropy of Quantum Black Holes

    Directory of Open Access Journals (Sweden)

    Romesh K. Kaul

    2012-02-01

    Full Text Available In the Loop Quantum Gravity, black holes (or even more general Isolated Horizons are described by a SU(2 Chern-Simons theory. There is an equivalent formulation of the horizon degrees of freedom in terms of a U(1 gauge theory which is just a gauged fixed version of the SU(2 theory. These developments will be surveyed here. Quantum theory based on either formulation can be used to count the horizon micro-states associated with quantum geometry fluctuations and from this the micro-canonical entropy can be obtained. We shall review the computation in SU(2 formulation. Leading term in the entropy is proportional to horizon area with a coefficient depending on the Barbero-Immirzi parameter which is fixed by matching this result with the Bekenstein-Hawking formula. Remarkably there are corrections beyond the area term, the leading one is logarithm of the horizon area with a definite coefficient −3/2, a result which is more than a decade old now. How the same results are obtained in the equivalent U(1 framework will also be indicated. Over years, this entropy formula has also been arrived at from a variety of other perspectives. In particular, entropy of BTZ black holes in three dimensional gravity exhibits the same logarithmic correction. Even in the String Theory, many black hole models are known to possess such properties. This suggests a possible universal nature of this logarithmic correction.

  1. Soft Hair on Black Holes

    Science.gov (United States)

    Hawking, Stephen W.; Perry, Malcolm J.; Strominger, Andrew

    2016-06-01

    It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units.

  2. 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...

  3. Performance evaluation of two black nickel and two black chrome solar collectors

    Science.gov (United States)

    Losey, R.

    1977-01-01

    The test program was based on the evaluation of four unique solar collectors described below: (1) black nickel collector surface with a desiccant drying bed, (2) black nickel collector surface without a desiccant drying bed, (3) black chrome collector surface with a dessicant drying bed, and (4) black chrome collector surface without a desiccant drying bed. The test program included three distinct phases: Initial performance evaluation, natural environmental aging, and post-aging performance evaluation. Results of Phase III testing conclusively indicated a higher normalized efficiency for Black Chrome surfaces when compared to Black Nickel.

  4. Parasites and food: ripe for exploitation.

    Science.gov (United States)

    Thompson, R C Andrew

    2014-01-01

    Parasites are often exploited for emotive or political purposes. This is especially so for a number of foodborne parasitic zoonoses, where this exploitation may not necessarily best serve the public good.

  5. Boosting jet power in black hole spacetimes.

    Science.gov (United States)

    Neilsen, David; Lehner, Luis; Palenzuela, Carlos; Hirschmann, Eric W; Liebling, Steven L; Motl, Patrick M; Garrett, Travis

    2011-08-02

    The extraction of rotational energy from a spinning black hole via the Blandford-Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux.

  6. Kerr-Newman Black Hole In Quintessence

    CERN Document Server

    Xu, Zhaoyi

    2016-01-01

    We study the Kerr-Newman solutions of the Einstein-Maxwell equation in quintessence field around a black hole by Newman-Janis algorithm. From the horizon structure and stationary limit surfaces, we find that Kerr-Newman black hole exists an ergosphere with $r^{+} < r < r^{L}$, which is related to the parameters $\\omega$ and $\\alpha$. We obtain the general expression between $\\alpha$ and $\\omega$ if the cosmological horizon exists, in which for $\\omega=-1/2$, $\\alpha\\leq\\sqrt{2}/5$, and for $\\omega=-2/3$, $\\alpha\\leq 1/6$. For $\\omega=-2/3$, the result is same with rotational black hole in quintessence. The singularity of the black holes is the same with that of Kerr black hole. We also discuss the rotation velocity of the black holes on the equatorial plane for $\\omega =-2/3$ and $-1/2$.

  7. 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

  8. String condensation: Nemesis of Black Holes?

    CERN Document Server

    Hewitt, Michael

    2015-01-01

    This paper puts forward a conjecture that there are no black holes in M theory. We will show that a mechanism to prevent black hole formation is needed in 4 dimensions to make string theory a viable high energy model of quantum gravity. Black hole formation may be averted by a gravity regulation mechanism based on string condensation. In this scenario, black holes are replaced by `hot holograms' that form during gravitational collapse. The geometric conditions based on the properties of free thermalon solutions that are proposed for conversion to a high temperature hologram to occur, however, are local and generic in dimension and could apply throughout M space. This idea can be applied to resolve the problems presented by the process of black hole evaporation, which appears to be inconsistent with quantum information theory. Whereas, in the conventional view, black holes are real and firewalls are probably a chimera, in the scenario proposed here that situation would be reversed.

  9. What does a black hole look like?

    CERN Document Server

    Bailyn, Charles D

    2014-01-01

    Emitting no radiation or any other kind of information, black holes mark the edge of the universe--both physically and in our scientific understanding. Yet astronomers have found clear evidence for the existence of black holes, employing the same tools and techniques used to explore other celestial objects. In this sophisticated introduction, leading astronomer Charles Bailyn goes behind the theory and physics of black holes to describe how astronomers are observing these enigmatic objects and developing a remarkably detailed picture of what they look like and how they interact with their surroundings. Accessible to undergraduates and others with some knowledge of introductory college-level physics, this book presents the techniques used to identify and measure the mass and spin of celestial black holes. These key measurements demonstrate the existence of two kinds of black holes, those with masses a few times that of a typical star, and those with masses comparable to whole galaxies--supermassive black holes...

  10. Seeding Black Holes in Cosmological Simulations

    CERN Document Server

    Taylor, Philip

    2014-01-01

    We present a new model for the formation of black holes in cosmological simulations, motivated by the first star formation. Black holes form from high density peaks of primordial gas, and grow via both gas accretion and mergers. Massive black holes heat the surrounding material, suppressing star formation at the centres of galaxies, and driving galactic winds. We perform an investigation into the physical effects of the model parameters, and obtain a `best' set of these parameters by comparing the outcome of simulations to observations. With this best set, we successfully reproduce the cosmic star formation rate history, black hole mass -- velocity dispersion relation, and the size -- velocity dispersion relation of galaxies. The black hole seed mass is 10^3Msun, which is orders of magnitude smaller than has been used in previous cosmological simulations with active galactic nuclei, but suggests that the origin of the seed black holes is the death of Population III stars.

  11. Black hole chemistry: thermodynamics with Lambda

    CERN Document Server

    Kubiznak, David; Teo, Mae

    2016-01-01

    We review recent developments on the thermodynamics of black holes in extended phase space, where the cosmological constant is interpreted as thermodynamic pressure and treated as a thermodynamic variable in its own right. In this approach, the mass of the black hole is no longer regarded as internal energy, rather it is identified with the chemical enthalpy. This leads to an extended dictionary for black hole thermodynamic quantities, in particular a notion of thermodynamic volume emerges for a given black hole spacetime. This volume is conjectured to satisfy the reverse isoperimetric inequality - an inequality imposing a bound on the amount of entropy black hole can carry for a fixed thermodynamic volume. New thermodynamic phase transitions naturally emerge from these identifications. Namely, we show that black holes can be understood from the viewpoint of chemistry, in terms of concepts such as Van der Waals fluids, reentrant phase transitions, and triple points. We also review the recent attempts at exten...

  12. Boosting jet power in black hole spacetimes

    CERN Document Server

    Neilsen, David; Palenzuela, Carlos; Hirschmann, Eric W; Liebling, Steven L; Motl, Patrick M; Garret, T

    2010-01-01

    The extraction of rotational energy from a spinning black hole via the Blandford-Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux.

  13. Weighing black holes in the universe

    Institute of Scientific and Technical Information of China (English)

    WU Xue-bing

    2006-01-01

    The determination of the mass of black holes in our universe is crucial to understand their physics nature but is a great challenge to scientists.In this paper Ⅰ briefly review some methods that are currently used to estimate the mass of black holes,especially those in X-ray binary systems and in galactic nuclei.Our recent progress in improving the mass estimates of supermasssive black holes in active galactic nuclei by involving some empirical relations is presented.Finally Ⅰ point out the similarities and common physics in Galactic black hole X-ray binaries and active galactic nuclei,and demonstrate that the black hole mass estimation is very much helpful to understand the accretion physics around black holes.

  14. The thermal radiation from dynamic black holes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Using the related formula of dynamic black holes, the instantaneous radiation energy density of the general spherically symmetric charged dynamic black hole and the arbitrarily accelerating charged dynamic black hole is calculated. It is found that the instantaneous radiation energy density of black hole is always proportional to the quartic of the temperature of event horizon in the same direction. The proportional coefficient of generalized Stefan-Boltzmann is no longer a constant, and it becomes a dynamic coefficient that is related to the event horizon changing rate, space-time structure near event horizon and the radiation absorption coefficient of the black hole. It is shown that there should be an internal relation between the gravitational field around black hole and its thermal radiation.

  15. Reversible Carnot cycle outside a black hole

    Institute of Scientific and Technical Information of China (English)

    Deng Xi-Hao; Gao Si-Jie

    2009-01-01

    A Carnot cycle outside a Schwarzschild black hole is investigated in detail. We propose a reversible Carnot cycle with a black hole being the cold reservoir. In our model, a Carnot engine operates between a hot reservoir with temperature T1 and a black hole with Hawking temperature Th. By naturally extending the ordinary Carnot cycle to the black hole system, we show that the thermal efficiency for a reversible process can reach the maximal efficiency 1-TH/T1 Consequently, black holes can be used to determine the thermodynamic temperature by means of the Carnot cycle. The role of the atmosphere around the black hole is discussed. We show that the thermal atmosphere provides a necessary mechanism to make the process reversible.

  16. Information Retention by Stringy Black Holes

    CERN Document Server

    AUTHOR|(CDS)2108556

    2015-01-01

    Building upon our previous work on two-dimensional stringy black holes and its extension to spherically-symmetric four-dimensional stringy black holes, we show how the latter retain information. A key r\\^ole is played by an infinite-dimensional $W_\\infty$ symmetry that preserves the area of an isolated black-hole horizon and hence its entropy. The exactly-marginal conformal world-sheet operator representing a massless stringy particle interacting with the black hole necessarily includes a contribution from $W_\\infty$ generators in its vertex function. This admixture manifests the transfer of information between the string black hole and external particles. We discuss different manifestations of $W_\\infty$ symmetry in black-hole physics and the connections between them.

  17. Instability of ultra-spinning black holes

    Energy Technology Data Exchange (ETDEWEB)

    Emparan, Roberto [Departament de Fisica Fonamental and C.E.R. en Astrofisica, Fisica de Particules i Cosmologia, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Institucio Catalana de Recerca i Estudis Avancats (ICREA) (Spain); Myers, Robert C. [Perimeter Institute for Theoretical Physics, 35 King Street North, Waterloo, Ontario N2J 2W9 (Canada) and Department of Physics, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)]. E-mail: rmyers@perimeterinstitute.ca

    2003-09-01

    It has long been known that, in higher-dimensional general relativity, there are black hole solutions with an arbitrarily large angular momentum for a fixed mass. We examine the geometry of the event horizon of such ultra-spinning black holes and argue that these solutions become unstable at large enough rotation. Hence we find that higher-dimensional general relativity imposes an effective 'Kerr-bound' on spinning black holes through a dynamical decay mechanism. Our results also give indications of the existence of new stationary black holes with 'rippled' horizons of spherical topology. We consider various scenarios for the possible decay of ultra-spinning black holes, and finally discuss the implications of our results for black holes in braneworld scenarios. (author)

  18. Non-abelian black string construction

    CERN Document Server

    Mazharimousavi, S Habib

    2010-01-01

    We present d+1-dimensional pure magnetic Yang-Mills (YM) black strings (or 1-branes) induced by the d-dimensional Einstein-Yang-Mills-Dilaton (EYMD) black holes. Incorporation of non-abelian fields in black strings, to our knowledge, has not been considered so far, for this reason we aim to fill this gap. Born-Infeld (BI) version of the YM field makes our starting point which goes to the standard YM field through a limiting procedure. The lifting from black holes to black strings, (with less number of fields) is by adding an extra, compact coordinate. This amounts to the change of horizon topology from S^{d-2} to a product structure. Our black string in 5-dimensions is a rather special one, with uniform Hawking temperature and non-asymptotically flat Local isometry in the abelian limit with the space of colliding plane waves is discussed.

  19. Microcanonical Description of (Micro Black Holes

    Directory of Open Access Journals (Sweden)

    Benjamin Harms

    2011-02-01

    Full Text Available The microcanonical ensemble is the proper ensemble to describe black holes which are not in thermodynamic equilibrium, such as radiating black holes. This choice of ensemble eliminates the problems, e.g., negative specific heat (not allowed in the canonical ensemble and loss of unitarity, encountered when the canonical ensemble is used. In this review we present an overview of the weaknesses of the standard thermodynamic description of black holes and show how the microcanonical approach can provide a consistent description of black holes and their Hawking radiation at all energy scales. Our approach is based on viewing the horizon area as yielding the ensemble density at fixed system energy. We then compare the decay rates of black holes in the two different pictures. Our description is particularly relevant for the analysis of micro-black holes whose existenceis predicted in models with extra-spatial dimensions.

  20. Admix Compatibility in Carbon Black Loaded Toners

    Institute of Scientific and Technical Information of China (English)

    Paul C. Julien

    2004-01-01

    In a xerographic system where the charge on the toner is controlled by the electrical nature of the carbon black used as a pigment, it is found that the speed with which added toner is charged to the proper level depends on the relative electrical negativity of the carbon black in the original and added toner. This is due to the fact that the incumbent toner typically shares its charge with the new toner through charge exchange among the conductive carbon black particles. If the carbon blacks are electrically dissimilar, this charge sharing may fail.Thus, a toner may work well by itself in a machine, but the same toner may fail when added to a machine already running with a toner from a different vendor or even a different lot of toner from the same vendor. Thus the electrical nature of the carbon black needs to be controlled. This can be done by controlling the oxidation of the carbon black.

  1. Black Feminism: An Integrated Review of Literature.

    Science.gov (United States)

    Love, Katie L

    2016-01-01

    This study presents a systematic literature review exploring the uses and potential benefits of Black Feminism in nursing research. Black Feminism may benefit knowledge development for nursing in a variety of ways, such as illuminating the multifaceted factors of Black women's identities in helping scholars move away from generalization of experiences, to improve understanding of health disparities, and making such changes by broadening the social consciousness of the nurse researchers, who are predominantly White. Discrimination in health disparities may be deconstructed if the focus is placed on asking different research questions and offering different interventions with the social structures that contributes to such actions. When Black Feminism guides the research method (including research questions and analysis), the accuracy of representing the experiences of Black women is increased. In this research, Black Feminism highlights experience, coping mechanisms, spiritual values, a tradition of strength, and a holistic view of identity.

  2. Oscillator level for black holes and black rings

    Energy Technology Data Exchange (ETDEWEB)

    Emparan, Roberto [Institucio Catalana de Recerca i Estudis Avancats (ICREA), Barcelona (Spain); Departament de Fisica Fonamental and CER en Astrofisica, Fisica de Particules i Cosmologia, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Mateos, David [Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2 L 2Y5 (Canada)

    2005-09-07

    Microscopic calculations of the Bekenstein-Hawking entropy of supersymmetric black holes in string theory are typically based on the application to a dual 2D CFT of Cardy's formula, S=2{pi}{radical}cq{sub 0}/6, where c is the central charge and q{sub 0} is the oscillator level. In the CFT, q{sub 0} is non-trivially related to the total momentum. We identify a Komar integral that equals q{sub 0} when evaluated at the horizon, and the total momentum when evaluated at asymptotic infinity, thus providing a gravitational dual of the CFT result.

  3. 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.

  4. How to End Colonial Domination of Black America: A Challenge to Black Psychologists

    Science.gov (United States)

    Howard, Joseph Hannibal, III

    1970-01-01

    Argues that Black people must engage in a therapeutic struggle which stresses Afro-American history and nationalism, and that Black professionals must shed narrow confines of academic disciplines and think as social scientists. (KG)

  5. Joint evolution of black holes and galaxies

    CERN Document Server

    Colpi, M; Haardt, F

    2006-01-01

    OBSERVATIONAL EVIDENCE FOR SUPERMASSIVE BLACK HOLES Introduction Some Useful Formalism General Considerations Resolved Stellar Dynamics Gas as a Tracer of the Gravitational Potential Tackling the Unresolvable: Reverberation Mapping Scaling Relations for SMBHs Black Hole Demographics The Future JOINT EVOLUTION OF BLACK HOLES AND GALAXIES: OBSERVATIONAL ISSUES Galaxy Activity: Generalities Local Evidence on the Interplay Between the Stellar and Gravitational Origin of AGN Activity The Cosmic History of Galaxy Activity Constraints on the Cosmic Energy Budget Current Observational Programs and Fut

  6. Defense Downsizing and Blacks in the Military

    Science.gov (United States)

    1993-06-01

    8217IIa NAVAL POSTGRADUATE SCHOOL Monterey, California AD-A272 415 THESIS DEFENSE DOWNSIZING AND BLACKS IN THE MILITARY by Roy L. Nixon June 1993 Thesis...include security classification) DEFENSE DOWNSIZING AND BLACKS IN TIE MILITARY 12 Plersonal Author(s) Roy L. Nixon 1 3a Type of Report I13b Time Covered...end of the draft. However. the armed forces are now engaged in the process of downsizing , and there is some speculation that blacks may be

  7. Superradiance by mini black holes with mirror

    OpenAIRE

    Lee, Jong-Phil

    2011-01-01

    The superradiant scattering of massive scalar particles by a rotating mini black hole is investigated. Imposing the mirror boundary condition, the system becomes the so called black-hole bomb where the rotation energy of the black hole is transferred to the scattered particle exponentially with time. Bulk emissions as well as brane emissions are considered altogether. It is found that the largest effects are expected for the brane emission of lower angular modes with lighter mass and larger a...

  8. Test fields cannot destroy extremal black holes

    Science.gov (United States)

    Natário, José; Queimada, Leonel; Vicente, Rodrigo

    2016-09-01

    We prove that (possibly charged) test fields satisfying the null energy condition at the event horizon cannot overspin/overcharge extremal Kerr-Newman or Kerr-Newman-anti de Sitter black holes, that is, the weak cosmic censorship conjecture cannot be violated in the test field approximation. The argument relies on black hole thermodynamics (without assuming cosmic censorship), and does not depend on the precise nature of the fields. We also discuss generalizations of this result to other extremal black holes.

  9. Dyonic Non-Abelian Black Holes

    OpenAIRE

    Brihaye, Y.; Hartmann, B.; Kunz, J; Tell, N.

    1999-01-01

    We study static spherically symmetric dyonic black holes in Einstein-Yang-Mills-Higgs theory. As for the magnetic non-abelian black holes, the domain of existence of the dyonic non-abelian black holes is limited with respect to the horizon radius and the dimensionless coupling constant $\\alpha$, which is proportional to the ratio of vector meson mass and Planck mass. At a certain critical value of this coupling constant, $\\hat \\alpha$, the maximal horizon radius is attained. We derive analyti...

  10. Black Hole Entropy without Brick Walls

    OpenAIRE

    Demers, J. -G.; Lafrance, R.; Myers, R. C.

    1995-01-01

    We present evidence which confirms a suggestion by Susskind and Uglum regarding black hole entropy. Using a Pauli-Villars regulator, we find that 't Hooft's approach to evaluating black hole entropy through a statistical-mechanical counting of states for a scalar field propagating outside the event horizon yields precisely the one-loop renormalization of the standard Bekenstein-Hawking formula, $S=\\A/(4G)$. Our calculation also yields a constant contribution to the black hole entropy, a contr...

  11. Speciation of Black-necked Crane

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on the concepts of species and speciation,the speciation of Black-necked Grane(Grus nigricollis) was discussed using bio-geographic principles and some evidences suggest that Black-necked Grane had a close relationship with Red-crowned Crane(Grus japonensis).The Qinghai-Tibetan Plateau uplift may be the most important factor in allopatric speciation for Black-necked Crane.

  12. Quantum aspects of black hole entropy

    Indian Academy of Sciences (India)

    Parthasarathi Majumdar

    2000-10-01

    This survey intends to cover recent approaches to black hole entropy which attempt to go beyond the standard semiclassical perspective. Quantum corrections to the semiclassical Bekenstein–Hawking area law for black hole entropy, obtained within the quantum geometry framework, are treated in some detail. Their ramification for the holographic entropy bound for bounded stationary spacetimes is discussed. Four dimensional supersymmetric extremal black holes in string-based = 2 supergravity are also discussed, albeit more briefly.

  13. The thermodynamics in a dynamical black hole

    Institute of Scientific and Technical Information of China (English)

    Bo LIU; Wen-biao LIU

    2009-01-01

    Considering the back-reaction of emitting particles to the black hole, a "new" horizon is suggested where thermodynamics can be built in the dynamical black hole. It, at least, means that the thermodynamics of a dynamical black hole should not be constructed at the original event horizon any more. The temperature, "new" horizon position and radiating particles' energy will be consistent again under the theory of equilibrium thermodynamical system.

  14. Noncommutative Black Holes and the Singularity Problem

    Energy Technology Data Exchange (ETDEWEB)

    Bastos, C; Bertolami, O [Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Dias, N C; Prata, J N, E-mail: cbastos@fisica.ist.utl.pt, E-mail: orfeu.bertolami@fc.up.pt, E-mail: ncdias@mail.telepac.pt, E-mail: joao.prata@mail.telepac.pt [Departamento de Matematica, Universidade Lusofona de Humanidades e Tecnologias, Avenida Campo Grande, 376, 1749-024 Lisboa (Portugal)

    2011-09-22

    A phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model is considered to study the interior of a Schwarzschild black hole. Due to the divergence of the probability of finding the black hole at the singularity from a canonical noncommutativity, one considers a non-canonical noncommutativity. It is shown that this more involved type of noncommutativity removes the problem of the singularity in a Schwarzschild black hole.

  15. Spinning a charged dilaton black hole

    CERN Document Server

    Shiraishi, Kiyoshi

    2015-01-01

    A charged dilaton black hole which possesses infinitesimal angular momentum is studied. We find that the gyromagnetic ratio of the dilaton black hole depends not only on the parameter which appears in the interaction between the dilaton and the electric field but also nonlinearly on the ratio of the charge to the mass of the black hole. The moment of inertia for the charged dilaton hole in the limit of infinitesimal angular momentum is also calculated.

  16. Black holes in the milky way galaxy.

    Science.gov (United States)

    Filippenko, A V

    1999-08-31

    Extremely strong observational evidence has recently been found for the presence of black holes orbiting a few relatively normal stars in our Milky Way Galaxy and also at the centers of some galaxies. The former generally have masses of 4-16 times the mass of the sun, whereas the latter are "supermassive black holes" with millions to billions of solar masses. The evidence for a supermassive black hole in the center of our galaxy is especially strong.

  17. Schwarzchild Black Holes in Matrix Theory, 2

    CERN Document Server

    Banks, T; Klebanov, Igor R; Susskind, Leonard

    1998-01-01

    We present a crude Matrix Theory model for Schwarzchild black holes in uncompactified dimension greater than 5. The model accounts for the size, entropy, and long range static interactions of black holes. The key feature of the model is a Boltzmann gas of D0 branes, a concept which depends on certain qualitative features of Matrix Theory which previously have not been utilized in studies of black holes.

  18. Geon black holes and quantum field theory

    CERN Document Server

    Louko, Jorma

    2010-01-01

    Black hole spacetimes that are topological geons in the sense of Sorkin can be constructed by taking a quotient of a stationary black hole that has a bifurcate Killing horizon. We discuss the geometric properties of these geon black holes and the Hawking-Unruh effect on them. We in particular show how correlations in the Hawking-Unruh effect reveal to an exterior observer features of the geometry that are classically confined to the regions behind the horizons.

  19. Black Holes and Gravitational Properties of Antimatter

    CERN Document Server

    Hajdukovic, D

    2006-01-01

    We speculate about impact of antigravity (i.e. gravitational repulsion between matter and antimatter) on the creation and emission of particles by a black hole. If antigravity is present a black hole made of matter may radiate particles as a black body, but this shouldn't be true for antiparticles. It may lead to radical change of radiation process predicted by Hawking and should be taken into account in preparation of the attempt to create and study mini black holes at CERN. Gravity, including antigravity is more than ever similar to electrodynamics and such similarity with a successfully quantized interaction may help in quantization of gravity.

  20. Schwarzschild black holes can wear scalar wigs

    CERN Document Server

    Barranco, Juan; Degollado, Juan Carlos; Diez-Tejedor, Alberto; Megevand, Miguel; Alcubierre, Miguel; Núñez, Darío; Sarbach, Olivier

    2012-01-01

    We study the evolution of a massive scalar field surrounding a Schwarzschild black hole and find configurations that can survive for arbitrarily long times, provided the black hole or the scalar field mass is small enough. In particular, both ultra-light scalar field dark matter around supermassive black holes and axion-like scalar fields around primordial black holes can survive for cosmological times. Moreover, these results are quite generic, in the sense that fairly arbitrary initial data evolves, at late times, as a combination of those long-lived configurations.