Distinct Lasing Operation From Chirped InAs/InP Quantum-Dash Laser

KAUST Repository

Khan, Mohammed Zahed Mustafa

2013-08-01

We study the enhanced inhomogeneity across the InAs quantum-dash (Qdash) layers by incorporating a chirped AlGaInAs barrier thickness in the InAs/InP laser structure. The lasing operation is investigated via Fabry-Pérot ridge-waveguide laser characterization, which shows a peculiar behavior under quasi-continuous-wave (QCW) operation. Continuous energy transfer between different dash ensembles initiated quenching of lasing action among certain dash groups, causing a reduced intensity gap in the lasing spectra. We discuss these characteristics in terms of the quasi-zero-dimensional density of states (DOS) of dashes and the active region inhomogeneity. © 2009-2012 IEEE.

Road Lane Detection by Discriminating Dashed and Solid Road Lanes Using a Visible Light Camera Sensor.

Science.gov (United States)

Hoang, Toan Minh; Hong, Hyung Gil; Vokhidov, Husan; Park, Kang Ryoung

2016-08-18

With the increasing need for road lane detection used in lane departure warning systems and autonomous vehicles, many studies have been conducted to turn road lane detection into a virtual assistant to improve driving safety and reduce car accidents. Most of the previous research approaches detect the central line of a road lane and not the accurate left and right boundaries of the lane. In addition, they do not discriminate between dashed and solid lanes when detecting the road lanes. However, this discrimination is necessary for the safety of autonomous vehicles and the safety of vehicles driven by human drivers. To overcome these problems, we propose a method for road lane detection that distinguishes between dashed and solid lanes. Experimental results with the Caltech open database showed that our method outperforms conventional methods.

Iron Kα line of Kerr black holes with scalar hair

Energy Technology Data Exchange (ETDEWEB)

Ni, Yueying; Zhou, Menglei; Bambi, Cosimo [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 220 Handan Road, 200433 Shanghai (China); Cárdenas-Avendaño, Alejandro [Programa de Matemática, Fundación Universitaria Konrad Lorenz, Carrera 9 Bis No. 62-43, 110231 Bogotá (Colombia); Herdeiro, Carlos A R; Radu, Eugen, E-mail: yyni13@fudan.edu.cn, E-mail: mlzhou13@fudan.edu.cn, E-mail: alejandro.cardenasa@konradlorenz.edu.co, E-mail: bambi@fudan.edu.cn, E-mail: herdeiro@ua.pt, E-mail: eugen.radu@ua.pt [Departamento de Física da Universidade de Aveiro and Center for Research and Development in Mathematics and Applications (CIDMA), Campus de Santiago, 3810-183 Aveiro (Portugal)

2016-07-01

Recently, a family of hairy black holes in 4-dimensional Einstein gravity minimally coupled to a complex, massive scalar field was discovered [1]. Besides the mass M and spin angular momentum J , these objects are characterized by a Noether charge Q , measuring the amount of scalar hair, which is not associated to a Gauss law and cannot be measured at spatial infinity. Introducing a dimensionless scalar hair parameter q , ranging from 0 to 1, we recover (a subset of) Kerr black holes for q = 0 and a family of rotating boson stars for q = 1. In the present paper, we explore the possibility of measuring q for astrophysical black holes with current and future X-ray missions. We study the iron Kα line expected in the reflection spectrum of such hairy black holes and we simulate observations with Suzaku and eXTP. As a proof of concept, we point out, by analyzing a sample of hairy black holes, that current observations can already constrain the scalar hair parameter q , because black holes with q close to 1 would have iron lines definitively different from those we observe in the available data. We conclude that a detailed scanning of the full space of solutions, together with data from the future X-ray missions, like eXTP, will be able to put relevant constraints on the astrophysical realization of Kerr black holes with scalar hair.

Genetic dissection of black grain rice by the development of a near isogenic line.

Science.gov (United States)

Maeda, Hiroaki; Yamaguchi, Takuya; Omoteno, Motoyasu; Takarada, Takeshi; Fujita, Kenji; Murata, Kazumasa; Iyama, Yukihide; Kojima, Yoichiro; Morikawa, Makiko; Ozaki, Hidenobu; Mukaino, Naoyuki; Kidani, Yoshinori; Ebitani, Takeshi

2014-06-01

Rice (Oryza sativa L.) can produce black grains as well as white. In black rice, the pericarp of the grain accumulates anthocyanin, which has antioxidant activity and is beneficial to human health. We developed a black rice introgression line in the genetic background of Oryza sativa L. 'Koshihikari', which is a leading variety in Japan. We used Oryza sativa L. 'Hong Xie Nuo' as the donor parent and backcrossed with 'Koshihikari' four times, resulting in a near isogenic line (NIL) for black grains. A whole genome survey of the introgression line using DNA markers suggested that three regions, on chromosomes 1, 3 and 4 are associated with black pigmentation. The locus on chromosome 3 has not been identified previously. A mapping analysis with 546 F2 plants derived from a cross between the black rice NIL and 'Koshihikari' was evaluated. The results indicated that all three loci are essential for black pigmentation. We named these loci Kala1, Kala3 and Kala4. The black rice NIL was evaluated for eating quality and general agronomic traits. The eating quality was greatly superior to that of 'Okunomurasaki', an existing black rice variety. The isogenicity of the black rice NIL to 'Koshihikari' was very high.

DASH (disabilities of the arm, shoulder, and hand) evaluation of QOL for carpal tunnel syndrome

International Nuclear Information System (INIS)

Morita, Akimasa; Kawamoto, Masataka; Fujisawa, Kouzou; Tsujii, Masaya; Hirata, Hitoshi

2006-01-01

The questionnaire on the disabilities of the arm, shoulder, and hand is a region-specific, self-administered outcome instrument that is developed as a measure of self-rate upper extremity disability and symptoms. Last year, the Japanese version of disabilities of the arm, shoulder and hand (DASH) was cross-culturally adapted. The main purpose of this study is to analyze the relationship between DASH and clinical assessment (findings of MRI and electrodiagnostic parameters). The subjects comprised 41 patients (6 males and 35 females) with carpal tunnel syndrome (CTS), except for cases with other upper extremity disorders. These subjects prospectively completed DASH 1 (disability module), DASH 2 (symptom module), and DASH (disability and symptom module) before the release of the open carpal tunnel. The patients were divided into 3 groups based on the symptom duration (A: shorter than 3 months, B: 4-11 months, C: longer than 12 months). All patients were preoperatively assessed with regard to sensory conduction velocity (SCV) and compound muscle action potential (CMAP). In addition, all patients underwent MRI in order to evaluate the flexor tenosynovial swelling represented by palmar bowing of the flexor retinaculum (PBFR). The relationships were estimated using the Spearman rank score, unpaired t tests, and Bonferroni tests. DASH 2 scores indicated greater responsiveness than DASH 1, which reflected the character of CTS. DASH 1 scores were higher in patients who were affected in their dominant hand than in those whose nondominant hand was affected. The DASH scores decreased significantly in groups A and B, with the exception of C. However, DASH did not show any correlation either with the parameters, age, or MRI assessment. DASH can be used for the research of preoperative outcomes related to CTS. It also has the advantage of being useful in assessing and comparing the outcome for various other hand disorders. (author)

ADAPTATION OF DASH OUTCOME MEASURES TO SLOVENIAN POPULATION - FUNCTIONALITY OF ARM, SHOULDER AND HAND

Directory of Open Access Journals (Sweden)

Katja Semprimožnik

2015-04-01

Full Text Available  ABSTRACT BackgroundIn Slovenia, there is no test for upper limb function, which would be uniform for all institutions and would allow comparison of results of the therapy and upper limb rehabilitation with medical centers. MethodsAfter reviewing the existing hand function tests and current literature we decided to translate the DASH test - Disabilities of arm, shoulder and hand. Adaptation was tested on patient population in outpatient hand clinic, General hospital Celje and showed good validity, reliability and responsiveness. Results and discussionAdaptation of DASH test to Slovene population is a procedure, where language and cultural differences must be considered. Testing the adapted DASH in the general population shows good validity, reliability and responsiveness of adapted test. ConclusionTranslations DASH test, QuickDASH test and instructions for scoring the DASH outcome measures are approved by the Institute for Work and Health. Translations are published on their site and available for use.

Genetic dissection of black grain rice by the development of a near isogenic line

OpenAIRE

Maeda, Hiroaki; Yamaguchi, Takuya; Omoteno, Motoyasu; Takarada, Takeshi; Fujita, Kenji; Murata, Kazumasa; Iyama, Yukihide; Kojima, Yoichiro; Morikawa, Makiko; Ozaki, Hidenobu; Mukaino, Naoyuki; Kidani, Yoshinori; Ebitani, Takeshi

2014-01-01

Rice (Oryza sativa L.) can produce black grains as well as white. In black rice, the pericarp of the grain accumulates anthocyanin, which has antioxidant activity and is beneficial to human health. We developed a black rice introgression line in the genetic background of Oryza sativa L. ‘Koshihikari’, which is a leading variety in Japan. We used Oryza sativa L. ‘Hong Xie Nuo’ as the donor parent and backcrossed with ‘Koshihikari’ four times, resulting in a near isogenic line (NIL) for black g...

Road Lane Detection by Discriminating Dashed and Solid Road Lanes Using a Visible Light Camera Sensor

Directory of Open Access Journals (Sweden)

Toan Minh Hoang

2016-08-01

Full Text Available With the increasing need for road lane detection used in lane departure warning systems and autonomous vehicles, many studies have been conducted to turn road lane detection into a virtual assistant to improve driving safety and reduce car accidents. Most of the previous research approaches detect the central line of a road lane and not the accurate left and right boundaries of the lane. In addition, they do not discriminate between dashed and solid lanes when detecting the road lanes. However, this discrimination is necessary for the safety of autonomous vehicles and the safety of vehicles driven by human drivers. To overcome these problems, we propose a method for road lane detection that distinguishes between dashed and solid lanes. Experimental results with the Caltech open database showed that our method outperforms conventional methods.

Effects of dietary sodium and the DASH diet on the occurrence of headaches: results from randomised multicentre DASH-Sodium clinical trial.

Science.gov (United States)

Amer, Muhammad; Woodward, Mark; Appel, Lawrence J

2014-12-11

Headaches are a common medical problem, yet few studies, particularly trials, have evaluated therapies that might prevent or control headaches. We, thus, investigated the effects on the occurrence of headaches of three levels of dietary sodium intake and two diet patterns (the Dietary Approaches to Stop Hypertension (DASH) diet (rich in fruits, vegetables and low-fat dairy products with reduced saturated and total fat) and a control diet (typical of Western consumption patterns)). Randomised multicentre clinical trial. Post hoc analyses of the DASH-Sodium trial in the USA. In a multicentre feeding study with three 30 day periods, 390 participants were randomised to the DASH or control diet. On their assigned diet, participants ate food with high sodium during one period, intermediate sodium during another period and low sodium during another period, in random order. Occurrence and severity of headache were ascertained from self-administered questionnaires, completed at the end of each feeding period. The occurrence of headaches was similar in DASH versus control, at high (OR (95% CI)=0.65 (0.37 to 1.12); p=0.12), intermediate (0.57 (0.29 to 1.12); p=0.10) and low (0.64 (0.36 to 1.13); p=0.12) sodium levels. By contrast, there was a lower risk of headache on the low, compared with high, sodium level, both on the control (0.69 (0.49 to 0.99); p=0.05) and DASH (0.69 (0.49 to 0.98); p=0.04) diets. A reduced sodium intake was associated with a significantly lower risk of headache, while dietary patterns had no effect on the risk of headaches in adults. Reduced dietary sodium intake offers a novel approach to prevent headaches. NCT00000608. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

The PROMIS physical function correlates with the QuickDASH in patients with upper extremity illness.

Science.gov (United States)

Overbeek, Celeste L; Nota, Sjoerd P F T; Jayakumar, Prakash; Hageman, Michiel G; Ring, David

2015-01-01

To assess disability more efficiently with less burden on the patient, the National Institutes of Health has developed the Patient Reported Outcomes Measurement Information System (PROMIS) Physical Function-an instrument based on item response theory and using computer adaptive testing (CAT). Initially, upper and lower extremity disabilities were not separated and we were curious if the PROMIS Physical Function CAT could measure upper extremity disability and the Quick Disability of Arm, Shoulder and Hand (QuickDASH). We aimed to find correlation between the PROMIS Physical Function and the QuickDASH questionnaires in patients with upper extremity illness. Secondarily, we addressed whether the PROMIS Physical Function and QuickDASH correlate with the PROMIS Depression CAT and PROMIS Pain Interference CAT instruments. Finally, we assessed factors associated with QuickDASH and PROMIS Physical Function in multivariable analysis. A cohort of 93 outpatients with upper extremity illnesses completed the QuickDASH and three PROMIS CAT questionnaires: Physical Function, Pain Interference, and Depression. Pain intensity was measured with an 11-point ordinal measure (0-10 numeric rating scale). Correlation between PROMIS Physical Function and the QuickDASH was assessed. Factors that correlated with the PROMIS Physical Function and QuickDASH were assessed in multivariable regression analysis after initial bivariate analysis. There was a moderate correlation between the PROMIS Physical Function and the QuickDASH questionnaire (r=-0.55, p<0.001). Greater disability as measured with the PROMIS and QuickDASH correlated most strongly with PROMIS Depression (r=-0.35, p<0.001 and r=0.34, p<0.001 respectively) and Pain Interference (r=-0.51, p<0.001 and r=0.74, p<0.001 respectively). The factors accounting for the variability in PROMIS scores are comparable to those for the QuickDASH except that the PROMIS Physical Function is influenced by other pain conditions while the QuickDASH is

Simultaneous quantum dash-well emission in a chirped dash-in-well superluminescent diode with spectral bandwidth >700 nm

KAUST Repository

Khan, Mohammed Zahed Mustafa

2013-10-01

We report on the quantitative evidence of simultaneous amplified spontaneous emission from the AlGaInAs/InAs/ InP-based quantum-well (Qwell) and quantum-dashes (Qdash) in a multistack dash-in-an-asymmetric-well superluminescent diode heterostructure. As a result, an emission bandwidth (full width at half-maximum) of 700 nm is achieved, covering entire O-E-S-C-L-U communication bands, and a maximum continuous wave output power of 1.3 mW, from this device structure. This demonstration paves a way to bridge entire telecommunication bands through proper optimization of device gain region, bringing significant advances and impact to a variety of cross-disciplinary field applications. © 2013 Optical Society of America.

Simultaneous quantum dash-well emission in a chirped dash-in-well superluminescent diode with spectral bandwidth >700 nm

KAUST Repository

Khan, Mohammed Zahed Mustafa; Cha, Dong Kyu; Majid, Mohammed Abdul; Ng, Tien Khee; Ooi, Boon S.

2013-01-01

We report on the quantitative evidence of simultaneous amplified spontaneous emission from the AlGaInAs/InAs/ InP-based quantum-well (Qwell) and quantum-dashes (Qdash) in a multistack dash-in-an-asymmetric-well superluminescent diode heterostructure. As a result, an emission bandwidth (full width at half-maximum) of 700 nm is achieved, covering entire O-E-S-C-L-U communication bands, and a maximum continuous wave output power of 1.3 mW, from this device structure. This demonstration paves a way to bridge entire telecommunication bands through proper optimization of device gain region, bringing significant advances and impact to a variety of cross-disciplinary field applications. © 2013 Optical Society of America.

Asupan makan DASH-like diet untuk mencegah risiko hipertensi pada wanita prediabetes

Directory of Open Access Journals (Sweden)

Ayu Rahadiyanti

2015-01-01

Full Text Available Background: Prediabetics have cardiovascular risk factors such as obesity, hypertension, and dyslipidemia. Unhealthy food intake can increase the risk of hypertension in prediabetes. Prediabetes hypertension has the impact on increasing prevalence of diabetes and cardiovascular disease. A cohort study has shown that DASH diet is related to the lower incidence of hypertension in women (1. Objective: Of this study had the purpose to know that inappropriate DASH-like diet intake is associated with hypertension risk at prediabetes women in Puskesmas Tlogosari Kulon Semarang. Method: A cross-sectional study was conducted in Puskesmas Tlogosari Kulon area on January – March 2014 among 117 prediabetes women. The subjects were selected using consecutive sampling. Independent variable in this study was DASH-like diet intake which assessed from FFQ and the dependent variable was hypertension risk. The subject was classified as at risk for hypertension if, in seated position, the mean of the two measurements was ≥120/80 mmHg. Chi-Square test and logistic regression were used to analyze the data. Results: The mean of DASH-like diet score in subjects who were not at hypertension risk (3.31 was higher than subjects who were at hypertension risk (3.23. There was 90,77% person with hypertension risk who did not consume DASH-like diet properly. But the association of DASH-like diet intake with hypertension risk was not significant (p=0.194. The multivariate result showed that there was association between family history (p=0.047, obesity (p=0.016, and fat intake (p=0.015 with hypertension risk. Conclusion: Inappropriate DASH-like diet intake may increase the risk of hypertension, but it is not statistically significant.

Semiconductor Quantum Dash Broadband Emitters: Modeling and Experiments

KAUST Repository

Khan, Mohammed Zahed Mustafa

2013-10-01

Broadband light emitters operation, which covers multiple wavelengths of the electromagnetic spectrum, has been established as an indispensable element to the human kind, continuously advancing the living standard by serving as sources in important multi-disciplinary field applications such as biomedical imaging and sensing, general lighting and internet and mobile phone connectivity. In general, most commercial broadband light sources relies on complex systems for broadband light generation which are bulky, and energy hungry. \\tRecent demonstration of ultra-broadband emission from semiconductor light sources in the form of superluminescent light emitting diodes (SLDs) has paved way in realization of broadband emitters on a completely novel platform, which offered compactness, cost effectiveness, and comparatively energy efficient, and are already serving as a key component in medical imaging systems. The low power-bandwidth product is inherent in SLDs operating in the amplified spontaneous emission regime. A quantum leap in the advancement of broadband emitters, in which high power and large bandwidth (in tens of nm) are in demand. Recently, the birth of a new class of broadband semiconductor laser diode (LDs) producing multiple wavelength light in stimulated emission regime was demonstrated. This very recent manifestation of a high power-bandwidth-product semiconductor broadband LDs relies on interband optical transitions via quantum confined dot/dash nanostructures and exploiting the natural inhomogeneity of the self-assembled growth technology. This concept is highly interesting and extending the broad spectrum of stimulated emission by novel device design forms the central focus of this dissertation. \\tIn this work, a simple rate equation numerical technique for modeling InAs/InP quantum dash laser incorporating the properties of inhomogeneous broadening effect on lasing spectra was developed and discussed, followed by a comprehensive experimental analysis

iDASH: integrating data for analysis, anonymization, and sharing

Science.gov (United States)

Bafna, Vineet; Boxwala, Aziz A; Chapman, Brian E; Chapman, Wendy W; Chaudhuri, Kamalika; Day, Michele E; Farcas, Claudiu; Heintzman, Nathaniel D; Jiang, Xiaoqian; Kim, Hyeoneui; Kim, Jihoon; Matheny, Michael E; Resnic, Frederic S; Vinterbo, Staal A

2011-01-01

iDASH (integrating data for analysis, anonymization, and sharing) is the newest National Center for Biomedical Computing funded by the NIH. It focuses on algorithms and tools for sharing data in a privacy-preserving manner. Foundational privacy technology research performed within iDASH is coupled with innovative engineering for collaborative tool development and data-sharing capabilities in a private Health Insurance Portability and Accountability Act (HIPAA)-certified cloud. Driving Biological Projects, which span different biological levels (from molecules to individuals to populations) and focus on various health conditions, help guide research and development within this Center. Furthermore, training and dissemination efforts connect the Center with its stakeholders and educate data owners and data consumers on how to share and use clinical and biological data. Through these various mechanisms, iDASH implements its goal of providing biomedical and behavioral researchers with access to data, software, and a high-performance computing environment, thus enabling them to generate and test new hypotheses. PMID:22081224

DASH for asthma: A pilot study of the DASH diet in not-well-controlled adult asthma⋆

Science.gov (United States)

Ma, Jun; Strub, Peg; Lavori, Phillip W.; Buist, A. Sonia; Camargo, Carlos A.; Nadeau, Kari C.; Wilson, Sandra R.; Xiao, Lan

2014-01-01

This pilot study aims to provide effect size confidence intervals, clinical trial and intervention feasibility data, and procedural materials for a full-scale randomized controlled trial that will determine the efficacy of Dietary Approaches to Stop Hypertension (DASH) as adjunct therapy to standard care for adults with uncontrolled asthma. The DASH diet encompasses foods (e.g., fresh fruit, vegetables, and nuts) and antioxidant nutrients (e.g., vitamins A, C, E, and zinc) with potential benefits for persons with asthma, but it is unknown whether the whole diet is beneficial. Participants (n = 90) will be randomized to receive usual care alone or combined with a DASH intervention consisting of 8 group and 3 individual sessions during the first 3 months, followed by at least monthly phone consultations for another 3 months. Follow-up assessments will occur at 3 and 6 months. The primary outcome measure is the 7-item Juniper Asthma Control Questionnaire, a validated composite measure of daytime and nocturnal symptoms, activity limitations, rescue medication use, and percentage predicted forced expiratory volume in 1 second. We will explore changes in inflammatory markers important to asthma pathophysiology (e.g., fractional exhaled nitric oxide) and their potential to mediate the intervention effect on disease control. We will also conduct pre-specified subgroup analyses by genotype (e.g., polymorphisms on the glutathione S transferase gene) and phenotype (e.g., atopy, obesity). By evaluating a dietary pattern approach to improving asthma control, this study could advance the evidence base for refining clinical guidelines and public health recommendations regarding the role of dietary modifications in asthma management. PMID:23648395

DASH-FP, Multicomponent Time-Dependent Concentration Diffusion

International Nuclear Information System (INIS)

Apperson, C.E. Jr.; Carruthers, L.M.; Shinn, J.F.; Lee, C.E.

1995-01-01

1 - Description of program or function: The program DASH-FP calculates the transient concentration of multiple diffusing species with radioactive decay. 2 - Method of solution: Uses finite difference and exponential operator techniques

Absence of quantized energy-states local diffusion in semiconductor quantum-dash structures

KAUST Repository

Tan, Cheeloon

2010-01-01

We present an analysis of InAs/InAlGaAs/InP quantum-dash structures utilizing different degrees of postgrowth-lattice-disordering. The observation of digital transitions among quantized states discards the origins of multiple excited states from a single group of dash ensembles.

Lo-Dash essentials

CERN Document Server

Boduch, Adam

2015-01-01

If you are a curious JavaScript developer interested simultaneously in tweaking the efficiency of your code, as well as improving the conciseness of it, and maintaining the readability of it, then this is the book for you. Ideally, the book is intended for readers already working on JavaScript projects and using frameworks such as jQuery and Backbone. Even if you're already using Lo-Dash, this book will show you how to use it efficiently. While extensive JavaScript experience isn't a requirement, you should have at least some prior programming experience in order to best understand the concept

Two Photon Induced Lasing in 1550 nm Quantum Dash Optical Gain Media

DEFF Research Database (Denmark)

Capua, Amir; Saal, Abigael; Reithmaier, Johann Peter

2011-01-01

We report on a unique lasing mechanism observed in quantum dash Gain media. While the gain media is electrically pumped below lasing threshold, a strong optical pulse excites carriers by two photon absorption into high energy states of the quantum dashes and wetting layer. Fast inter band carrier...

DASH Diet: Tips for Shopping and Cooking

Science.gov (United States)

... dash-in-brief-html. Accessed April 7, 2016. Essential kitchen equipment. American Heart Association. http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyCooking/Essential-Kitchen-Equipment_UCM_430098_Article.jsp. Accessed April 7, ...

From colour photographs to black-and-white line drawings: an assessment of chimpanzees' (Pan troglodytes') transfer behaviour.

Science.gov (United States)

Close, James; Call, Josep

2015-03-01

Over two experiments, we investigated the ability of two adolescent and two adult chimpanzees to generalise a learnt, pictorial categorisation to increasingly degraded and abstract stimuli. In Experiment 2, we further assessed the ability of the adolescent chimpanzees to engage in open-ended categorisation of black-and-white line drawings. The current results confirmed and extended previous findings, showing that sub-adult chimpanzees outperform adult chimpanzees in the categorisation of pictorial stimuli, particularly when the stimuli are more degraded and abstract in nature. However, none of the four chimpanzees showed positive transfer of their category learning to a set of black-and-white line drawings, and neither of the adolescent chimpanzees evidenced reliable open-ended categorisation of the black-and-white line drawings. The latter findings suggest that both sub-adult and adult chimpanzees find it difficult to recognise black-and-white line drawings, and that open-ended categorisation of black-and-white line drawings is challenging for chimpanzees.

MEKANISME SEGMENTASI LAJU BIT PADA DYNAMIC ADAPTIVE STREAMING OVER HTTP (DASH UNTUK APLIKASI VIDEO STREAMING

Directory of Open Access Journals (Sweden)

Muhammad Audy Bazly

2015-12-01

Full Text Available This paper aims to analyze Internet-based streaming video service in the communication media with variable bit rates. The proposed scheme on Dynamic Adaptive Streaming over HTTP (DASH using the internet network that adapts to the protocol Hyper Text Transfer Protocol (HTTP. DASH technology allows a video in the video segmentation into several packages that will distreamingkan. DASH initial stage is to compress the video source to lower the bit rate video codec uses H.26. Video compressed further in the segmentation using MP4Box generates streaming packets with the specified duration. These packages are assembled into packets in a streaming media format Presentation Description (MPD or known as MPEG-DASH. Streaming video format MPEG-DASH run on a platform with the player bitdash teritegrasi bitcoin. With this scheme, the video will have several variants of the bit rates that gave rise to the concept of scalability of streaming video services on the client side. The main target of the mechanism is smooth the MPEG-DASH streaming video display on the client. The simulation results show that the scheme based scalable video streaming MPEG- DASH able to improve the quality of image display on the client side, where the procedure bufering videos can be made constant and fine for the duration of video views

Blood Pressure-Lowering Mechanisms of the DASH Dietary Pattern

Directory of Open Access Journals (Sweden)

Pao-Hwa Lin

2012-01-01

Full Text Available Potential blood pressure- (BP- lowering mechanisms of the DASH dietary pattern were measured in 20 unmedicated hypertensive adults in a controlled feeding study. At screening, participants averaged 44.3±7.8 years, BMI 33.9±6.6 Kg/m2, and BP 144.2±9.38/88.5±6.03 mmHg. All consumed a control diet for one week, then were randomized to control or DASH for another two weeks (week one and two. With DASH, but not controls, SBP fell by 10.65±12.89 (=0.023 and 9.60±11.23 (=0.039 mmHg and DBP by 5.95±8.01 (=0.069 and 8.60±9.13 mmHg (=0.011 at the end of week one and two, respectively. Univariate regressions showed that changes in urinary sodium/potassium ratio (=1.99 and plasma renin activity (=−15.78 and percent change in plasma nitrite after hyperemia were associated with SBP changes at week one (all <0.05. Plasma nitrite following hyperemia showed a treatment effect (=0.014 and increased at week two (=0.001. Pulse wave velocity decreased over time with DASH (trend =0.019, and reached significance at week two (=0.026. This response may be mediated by an improvement in upregulation of nitric oxide bioavailability. Early natriuresis and reductions in oxidative stress cannot be ruled out. Future studies are needed to verify these findings, assess the possibility of earlier effects, and examine other potential mediators.

MPEG DASH SRD : Spatial Relationship Description

NARCIS (Netherlands)

Niamut, O.A.; Thomas, E.D.R.; D'Acunto, L.; Concolato, C.; Denoual, F.; Yong Lim, S.

2016-01-01

This paper presents the Spatial Representation Description (SRD)feature of the second amendment of MPEG DASH standard part 1, 23009-1:2014 [1]. SRD is an approach for streaming only spatial sub-parts of a video to display devices, in combination with the form of adaptive multi-rate streaming that is

Recent progress in InAs/InP quantum dash nanostructures and devices

KAUST Repository

Ooi, Boon S.; Khan, Mohammed Zahed Mustafa; Ng, Tien Khee

2016-01-01

In this talk, we will give an outline and introduction to the broad inter-band emission devices focusing on the InAs/InP quantum dash material system, device physics and establishment of ultrabroad stimulated emission behavior. In addition, technologies for growing these nanostructures as well as engineer the bandgap of quantum dash based system using epitaxy growth techniques and postgrowth intermixing methods will be presented. At device level, we will focus our discussion on our recent progress in extending the ultra-broad lasing emission from quantum dash lasers, and achievements in broad gain semiconductor optical amplifiers (SOA), mode locked lasers, comb-lasers, wide band superluminsect diodes fabricated on this material system. © 2015 IEEE.

Recent progress in InAs/InP quantum dash nanostructures and devices

KAUST Repository

Ooi, Boon S.

2016-03-24

In this talk, we will give an outline and introduction to the broad inter-band emission devices focusing on the InAs/InP quantum dash material system, device physics and establishment of ultrabroad stimulated emission behavior. In addition, technologies for growing these nanostructures as well as engineer the bandgap of quantum dash based system using epitaxy growth techniques and postgrowth intermixing methods will be presented. At device level, we will focus our discussion on our recent progress in extending the ultra-broad lasing emission from quantum dash lasers, and achievements in broad gain semiconductor optical amplifiers (SOA), mode locked lasers, comb-lasers, wide band superluminsect diodes fabricated on this material system. © 2015 IEEE.

High performance mode locking characteristics of single section quantum dash lasers.

Science.gov (United States)

Rosales, Ricardo; Murdoch, S G; Watts, R T; Merghem, K; Martinez, Anthony; Lelarge, Francois; Accard, Alain; Barry, L P; Ramdane, Abderrahim

2012-04-09

Mode locking features of single section quantum dash based lasers are investigated. Particular interest is given to the static spectral phase profile determining the shape of the mode locked pulses. The phase profile dependence on cavity length and injection current is experimentally evaluated, demonstrating the possibility of efficiently using the wide spectral bandwidth exhibited by these quantum dash structures for the generation of high peak power sub-picosecond pulses with low radio frequency linewidths.

Diagnostic status of hypertension on the adherence to the Dietary Approaches to Stop Hypertension (DASH diet

Directory of Open Access Journals (Sweden)

Hyun Kim, PhD

2016-12-01

Full Text Available The Dietary Approaches to Stop Hypertension (DASH diet is a widely recommended diet for individuals with hypertension. Adherence to the DASH diet has been shown to be effective for controlling hypertension, but it is unclear whether a hypertension diagnosis has an impact on adherence to the diet and nutrient intake. This study examined the association between hypertension diagnosis and the DASH nutrient intake using the multivariate linear regression method. The sample was composed of individuals with hypertension in the National Health and Nutrition Examination Survey (NHANES from 2007 to 2012. The outcome was the DASH accordance score (0 to 9 points, which measures the intake of nine nutrients compared to target amounts. Study findings indicate that a diagnostic status of hypertension was associated with increased consumption of sodium, saturated fat, total fat, and protein. Adherence to the DASH diet was more likely to be associated with health conditions such as obesity and heart diseases and lifestyle behaviors such as current smoking status and physical activity. Individuals diagnosed with hypertension showed less adherence to the DASH diet than those not diagnosed with hypertension, so a diagnosis of hypertension did not seem to provide an incentive to engage in healthy dietary behavior. Overall, regardless of diagnostic status, individuals with hypertension did not seem to follow the DASH guidelines.

Valve and dash-pot assembly

Science.gov (United States)

Chang, Shih-Chih

1986-01-01

A dash-pot valve comprising a cylinder submerged in the fluid of a housing and having a piston attached to a plunger projecting into the path of closing movement of a pivotal valve member. A vortex chamber in said cylinder is provided with tangentially directed inlets to generate vortex flow upon retraction of said plunger and effect increasing resistance against said piston to progressively retard the closing rate of said valve member toward its seat.

Wilson lines for AdS5 black strings

International Nuclear Information System (INIS)

Hristov, Kiril; Katmadas, Stefanos

2015-01-01

We describe a simple method of extending AdS 5 black string solutions of 5d gauged supergravity in a supersymmetric way by addition of Wilson lines along a circular direction in space. When this direction is chosen along the string, and due to the specific form of 5d supergravity that features Chern-Simons terms, the existence of magnetic charges automatically generates conserved electric charges in a 5d analogue of the Witten effect. Therefore we find a rather generic, model-independent way of adding electric charges to already existing solutions with no backreaction from the geometry or breaking of any symmetry. We use this method to explicitly write down more general versions of the Benini-Bobev black strings (http://dx.doi.org/10.1103/PhysRevLett.110.061601, http://dx.doi.org/10.1007/JHEP06(2013)005) and comment on the implications for the dual field theory and the similarities with generalizations of the Cacciatori-Klemm black holes (http://dx.doi.org/10.1007/JHEP01(2010)085) in AdS 4 .

Relationship of Sodium Intake and Blood Pressure Varies With Energy Intake: Secondary Analysis of the DASH (Dietary Approaches to Stop Hypertension)-Sodium Trial.

Science.gov (United States)

Murtaugh, Maureen A; Beasley, Jeannette M; Appel, Lawrence J; Guenther, Patricia M; McFadden, Molly; Greene, Tom; Tooze, Janet A

2018-05-01

Dietary Na recommendations are expressed as absolute amounts (mg/d) rather than as Na density (mg/kcal). Our objective was to determine whether the strength of the relationship of Na intake with blood pressure (BP) varied with energy intake. The DASH (Dietary Approaches to Stop Hypertension)-Sodium trial was a randomized feeding trial comparing 2 diets (DASH and control) and 3 levels of Na density. Participants with pre- or stage 1 hypertension consumed diets for 30 days in random order; energy intake was controlled to maintain body weight. This secondary analysis of 379 non-Hispanic black and white participants used mixed-effects models to assess the association of Na and energy intakes with BP. The relationships between absolute Na and both systolic and diastolic BP varied with energy intake. BP rose more steeply with increasing Na at lower energy intake than at higher energy intake ( P interaction<0.001). On the control diet with 2300 mg Na, both systolic and diastolic BP were higher (3.0 mm Hg; 95% confidence interval, 0.2-5.8; and 2.7 mm Hg; 95% confidence interval, 1.0-4.5, respectively) among those with lower energy intake (higher Na density) than among those with higher energy intake (lower Na density). The association of Na with systolic BP was stronger at lower levels of energy intake in both blacks and whites ( P <0.001). The association of Na and diastolic BP varied with energy intake only among blacks ( P =0.001). Sodium density should be considered as a metric for expressing dietary Na recommendations. © 2018 American Heart Association, Inc.

Adherence to the Dietary Approaches to Stop Hypertension (DASH) diet in relation to obesity among Iranian female nurses.

Science.gov (United States)

Barak, Farzaneh; Falahi, Ebrahim; Keshteli, Ammar Hassanzadeh; Yazdannik, Ahmadreza; Esmaillzadeh, Ahmad

2015-03-01

Limited observational studies have considered habitual consumption of the general population to examine the relationship between the Dietary Approaches to Stop Hypertension (DASH) diet and obesity. The aim of the present study was to investigate adherence to the DASH diet in relation to general and central obesity among female nurses in Isfahan, Iran. Cross-sectional study carried out among 293 female nurses aged >30 years who were selected by a multistage, cluster random sampling method. Usual dietary intakes were assessed using a validated FFQ. We constructed the DASH score based on foods and nutrients emphasized or minimized in the DASH diet, focusing on eight components: high intake of fruits, vegetables, nuts and legumes, low-fat dairy products and whole grains and low intakes of sodium, sweetened beverages, and red and processed meats. General and abdominal obesity were defined as BMI ≥ 25 kg/m2 and waist circumference ≥ 88 cm, respectively. Isfahan, Iran. Female nurses (n 293) aged >30 years. Increased adherence to the DASH diet was associated with older age (Pobesity between extreme quartiles of the DASH diet score. After adjustment for age, energy intake and other confounding factors, DASH diet score was not significantly associated with obesity. However, with further controlling for other dietary factors, those in the highest quartile of DASH diet score were 71 % less likely to have general obesity compared with those in the lowest quartile. In addition, following a DASH diet was inversely associated with central obesity after adjustment for potential confounders (OR=0.37; 95 % CI 0.14, 0.96). We found that adherence to the DASH diet was inversely related to central obesity among Iranian adult females. This association remained significant even after adjustment for potential confounders.

Emergency medicine task shifting: Quick dash outcome scores of upper extremity injury management

Directory of Open Access Journals (Sweden)

D.S. Frank*

2013-12-01

Results and conclusions: There were a total of 25 initial candidates, of which only 17 were able to complete the survey. Using the Quick DASH Outcome Measure, our 17 patients had a mean score of 29.5 (range 5.0– 56.8. When compared to the standardized Quick DASH outcomes (no work limitation at 27.5 vs. work limited by injury at 52.6 the non-physician clinicians appear to be performing upper extremity repairs with good outcomes. The key variable to successful repair was the initial injury type. Although accommodations needed to be made to the standard Quick DASH protocol, the tool appears to be usable in non-traditional settings.

Adherence to the DASH and Mediterranean diets is associated with decreased risk for gestational diabetes mellitus.

Science.gov (United States)

Izadi, Vajihe; Tehrani, Hatav; Haghighatdoost, Fahimeh; Dehghan, Atefeh; Surkan, Pamela J; Azadbakht, Leila

2016-10-01

Few studies have examined the association between adherence to the Dietary Approaches to Stop Hypertension (DASH) or Mediterranean (MED) diets and prevalence of gestational diabetes mellitus (GDM). The aim of the present study was to evaluate the association between the two diets and GDM. In a case-control hospital-based study, pregnant women with (n = 200) and without (n = 260) GMD were recruited. An average of three 24-h dietary records were used to assess participants' dietary intakes. DASH scores were calculated based on the Fung method and MED scores were calculated using the Trichopoulou method. GDM was defined as fasting glucose >95 mg/dL or 1-h postprandial glucose >140 mg/dL for the first time in the pregnancy. The risk for GDM was assessed across tertiles of DASH and MED scores. DASH and MED diets were negatively related to fasting blood glucose, hemoglobin A1c, and serum triacylglycerol concentrations. High-density lipoprotein cholesterol was significantly higher for those in the top tertile of the DASH diet but not the MED diet in comparison with the lowest tertile. Total serum cholesterol level was lower in the third tertile of the MED diet but not in the DASH diet. Participants in the highest tertile of the MED diet had 80% lower risk for GDM compared with those in the lowest tertile (Ptrend = 0.006). Greater adherence to the DASH eating plan was associated with 71% reduced risk for GDM (Ptrend = 0.006) after adjustment for potential confounders. Adherence to either the DASH or Mediterranean diet is associated with decreased risk for GDM. Copyright © 2016 Elsevier Inc. All rights reserved.

DASH Diet: Reducing Hypertension through Diet and Lifestyle

Science.gov (United States)

... include soy beans, collard greens and calcium-fortified beverages such as almond milk. Limit Saturated Fat A DASH diet is low in saturated fats, sodium and total fat. Studies have shown that a diet low in saturated ...

Terahertz-bandwidth coherence measurements of a quantum dash laser in passive and active mode-locking operation.

Science.gov (United States)

Martin, Eamonn; Watts, Regan; Bramerie, Laurent; Shen, Alexandre; Gariah, Harry; Blache, Fabrice; Lelarge, Francois; Barry, Liam

2012-12-01

This research carries out coherence measurements of a 42.7 GHz quantum dash (QDash) semiconductor laser when passively, electrically, and optically mode-locked. Coherence of the spectral lines from the mode-locked laser is determined by examining the radio frequency beat-tone linewidth as the mode spacing is increased up to 1.1 THz. Electric-field measurements of the QDash laser are also presented, from which a comparison between experimental results and accepted theory for coherence in passively mode-locked lasers has been performed.

Integrating Data for Analysis, Anonymization, and Sharing (iDASH)

Data.gov (United States)

U.S. Department of Health & Human Services — iDASH, the newest Common Fund National Center for Biomedical Computing, addresses fundamental challenges to research progress and enables global collaborations...

Coupling Fluid and Solute Dynamics Within the Ocular Surface Tear Film: A Modelling Study of Black Line Osmolarity

KAUST Repository

Zubkov, V. S.

2012-07-06

We present a mathematical model describing the spatial distribution of tear film osmolarity across the ocular surface of a human eye during one blink cycle, incorporating detailed fluid and solute dynamics. Based on the lubrication approximation, our model comprises three coupled equations tracking the depth of the aqueous layer of the tear film, the concentration of the polar lipid, and the concentration of physiological salts contained in the aqueous layer. Diffusive boundary layers in the salt concentration occur at the thinnest regions of the tear film, the black lines. Thus, despite large Peclet numbers, diffusion ameliorates osmolarity around the black lines, but nonetheless is insufficient to eliminate the build-up of solute in these regions. More generally, a heterogeneous distribution of solute concentration is predicted across the ocular surface, indicating that measurements of lower meniscus osmolarity are not globally representative, especially in the presence of dry eye. Vertical saccadic eyelid motion can reduce osmolarity at the lower black line, raising the prospect that select eyeball motions more generally can assist in alleviating tear film hyperosmolarity. Finally, our results indicate that measured evaporative rates will induce excessive hyperosmolarity at the black lines, even for the healthy eye. This suggests that further evaporative retardation at the black lines, for instance due to the cellular glycocalyx at the ocular surface or increasing concentrations of mucus, will be important for controlling hyperosmolarity as the black line thins. © 2012 Society for Mathematical Biology.

Effect of the DASH Diet on Pre- and Stage 1 Hypertensive Individuals in a Free-Living Environment

Directory of Open Access Journals (Sweden)

Joan Malloy-McFall

2010-01-01

Full Text Available Background Dietary Approaches to Stop Hypertension (DASH has been shown to successfully reduce systolic (SBP and diastolic blood pressure (DBP when evaluated in clinically controlled environments but there is a lack of information regarding the efficacy of the original DASH diet when it is applied in a free-living environment. Purpose To provide descriptive data as to the changes in blood pressure individuals could expect to achieve when following the DASH diet in a free-living environment for 4-weeks with no additional behavioral modifications. Methods Twenty, pre- and stage 1 hypertensive participants were randomly split into 2 groups; DASH (males N = 5, females N = 5, age = 38.5 ± 10.8 and control (males N = 7, females N = 3, age = 38.1 ± 11.1. The DASH group was instructed on how to follow the DASH diet on their own for 4-weeks while the control group continued their normal diet. SBP, DBP, body weight, 3-day food diaries and physical activity recall questionnaire data were collected pre and post intervention using a traditional person-to-person instructional technique. Results Two-way ANOVA demonstrated that there was a significant group (DASH, control by time (pre, post interaction for SBP ( P = 0.003 and no significant effects for DBP. The interaction was due to a significant reduction ( P < 0.001 in SBP in the DASH group (pre: 141.3 ± 11.3 mmHg vs. post: 130.7 ± 9.1 mmHg over the course of the intervention with no change in SBP in the control group (pre: 133.5 ± 6.6 mmHg vs. post: 131.9 ± 8.9 mmHg. Pearson's correlation analyses revealed that changes in potential moderators of blood pressure including body weight, BMI, sodium intake and total kilocalories were each not associated with changes in SBP (r ≤ 0.14, P ≥ 0.5 or DBP (r < 0.10, P ≥ 0.6 pre- to post-treatment. Chi-square demonstrated no significant differences in the number of participants per group (n = 4 DASH, n = 1 control who indicated increasing physical activity

Successfully recruiting a multicultural population: the DASH-Sodium experience.

Science.gov (United States)

Kennedy, Betty M; Conlin, Paul R; Ernst, Denise; Reams, Patrice; Charleston, Jeanne B; Appel, Lawrence J

2005-01-01

Recruiting practices employed by the four clinical centers participating in the Dietary Approaches to Stop Hypertension (DASH)-Sodium trial were examined to assess the most successful method of obtaining participants and to describe pertinent learning experiences gained as a result of the trial. The primary recruitment strategies employed by each center were mass mailing brochures (direct, coupon packs, or other) and mass media (advertisements in newspapers, radio, and television spots). Of 412 randomized participants, 265 (64%) were from mass distribution of brochures, 62 (15%) mass media, and 85 (21%) were prior study participants, referred by word-of-mouth, or reported coming from screening events and presentations. Although the most successful method of recruitment was mass mailing brochures, three times as many brochures were distributed to obtain similar success as in the initial DASH trial.

The value of modified DASH questionnaire for evaluation of elbow function after supracondylar fractures in children

Directory of Open Access Journals (Sweden)

Čolović Hristina

2008-01-01

Full Text Available Background/Aim. The Disabilities of the Arm, Shoulder and Hand (DASH Outcome Questionnaire represents a region- specific instrument for functional outcome measurement of hand function. The aim of the study was to analyze the correlation between the values of modified DASH questionnaire and change of elbow function after supracondylar fracture (SCF of humerus and to analyze the effects of early rehabilitation. Methods. The study included 35 schoolaged children with flexion of SCF of humerus without lesion of nerves. The patients were divided into two groups: group A in which rehabilitation started up to 14 days after the removal of fixation (20 children, and group B in which rehabilitation started after 15 days and more (15 children. The effects of the applied rehabilitation procedures were analyzed by measuring the range of motion of elbow and using modified DASH questionnaire. Testing was performed during the first examination, on the first day of rehabilitation (retest and after the rehabilitation. Pearson's coefficient of liner correlation was applied. Results. Statistically significant negative correlation of DASH score and extension was verified in all three measurements. The values for the first test and for the final test were highly significant (p < 0.001, as well as negative correlation of DASH score and flexion on the first test and retest (p < 0.01, and at the end of rehabilitation (p < 0.001 in the group B. For all three tests in the group A negative correlation without significant differences for DASH score and flexion was found. Conclusion. A modified DASH questionnaire correlates with objective parameters of final status of elbow after SCF in children and it is applicable to small series of patients. A positive effect of early rehabilitation of children with SCF was found.

Improved valve and dash-pot assembly

Science.gov (United States)

Chang, S.C.

1985-04-23

A dash-pot valve comprises a cylinder submerged in the fluid of a housing and have a piston attached to a plunger projecting into the path of closing movement of a pivotal valve member. A vortex chamber in said cylinder is provided with targentially directed inlets to generate vortex flow upon retraction of said plunger and effect increasing resistance against said piston to progressively retard the closing rate of said valve member toward its seat.

Quasar Black Hole Mass Estimates from High-Ionization Lines: Breaking a Taboo?

Directory of Open Access Journals (Sweden)

Paola Marziani

2017-09-01

Full Text Available Can high ionization lines such as CIV λ 1549 provide useful virial broadening estimators for computing the mass of the supermassive black holes that power the quasar phenomenon? The question has been dismissed by several workers as a rhetorical one because blue-shifted, non-virial emission associated with gas outflows is often prominent in CIV λ 1549 line profiles. In this contribution, we first summarize the evidence suggesting that the FWHM of low-ionization lines like H β and MgII λ 2800 provide reliable virial broadening estimators over a broad range of luminosity. We confirm that the line widths of CIV λ 1549 is not immediately offering a virial broadening estimator equivalent to the width of low-ionization lines. However, capitalizing on the results of Coatman et al. (2016 and Sulentic et al. (2017, we suggest a correction to FWHM CIV λ 1549 for Eddington ratio and luminosity effects that, however, remains cumbersome to apply in practice. Intermediate ionization lines (IP ∼ 20–30 eV; AlIII λ 1860 and SiIII] λ 1892 may provide a better virial broadening estimator for high redshift quasars, but larger samples are needed to assess their reliability. Ultimately, they may be associated with the broad-line region radius estimated from the photoionization method introduced by Negrete et al. (2013 to obtain black hole mass estimates independent from scaling laws.

A DASH dietary pattern and the risk of colorectal cancer in Canadian adults

OpenAIRE

Jones-McLean, E.; Hu, J.; Greene-Finestone, L. S.; de Groh, M.

2015-01-01

Introduction: Colorectal cancer (CRC) is a high incidence cancer affecting many Canadian adults each year. Diet is important in the etiology of CRC with many dietary components identified as potential risk factors. The Dietary Approaches to Stop Hypertension (DASH) diet is a well-established pattern to characterize overall eating. The purpose of this study was to characterize a DASH pattern within the Canadian context and to assess its relationship to the risk of CRC in Canadian adults. Metho...

Nanostructured Quantum Dots or Dashes in Photovoltaic Devices and Methods Thereof

Science.gov (United States)

Raffaele, Ryne P. (Inventor); Wilt, David M. (Inventor)

2015-01-01

A photovoltaic device includes one or more structures, an array of at least one of quantum dots and quantum dashes, at least one groove, and at least one conductor. Each of the structures comprises an intrinsic layer on one of an n type layer and a p type layer and the other one of the n type layer and the p type layer on the intrinsic layer. The array of at least one of quantum dots and quantum dashes is located in the intrinsic layer in at least one of the structures. The groove extends into at least one of the structures and the conductor is located along at least a portion of the groove.

Unique lasing mechanism of localized dispersive nanostructures in InAs/InGaAlAs quantum dash broad interband laser

KAUST Repository

Tan, C. L.

2010-02-11

The authors report on the nanowires-like and nanodots-like lasing behaviors in addition to multiple-wavelength interband transitions from InAs/InAlGaAs quantum dash (Qdash) lasers in the range of ~1550 nm. The presence of lasing actions simultaneously from two different dash ensembles, after postgrowth intermixing for crystalline quality improvement, indicate the absence of optical phonon emission due to the small variation in quantized interband transition energies. This effect is reproducible and shows different lasing characteristics from its quantum dot and quantum wire laser counterparts. Furthermore, the small energy spacing of only 25 nm (at center lasing wavelength of ~1550 nm) and the subsequent quenching of higher energy transition states at higher bias level in Qdash lasers suggest the absence of excited-state transition in highly inhomogeneous self-assembled Qdash structures. However, the appearance of a second lasing line in a certain range of high injection level, which is due to the presence of different sizes of dash assembles, corresponds to the transition from smaller size of Qdash ensembles in different planar active medium. This unique transition mechanism will affect the carrier dynamics, relaxation process in particular and further indicates localized finite carrier lifetime in all sizes of Qdash ensembles. These phenomena will lead to important consequences for the ground-state lasing efficiency and frequency modulation response of Qdash devices. In addition, these imply that proper manipulation of the Qdash ensembles will potentially result in localized nanolasers from individual ensemble and thus contributing towards enormously large envelope lasing coverage from semiconductor devices.

Dots and dashes: art, virtual reality, and the telegraph

Science.gov (United States)

Ruzanka, Silvia; Chang, Ben

2009-02-01

Dots and Dashes is a virtual reality artwork that explores online romance over the telegraph, based on Ella Cheever Thayer's novel Wired Love - a Romance in Dots and Dashes (an Old Story Told in a New Way)1. The uncanny similarities between this story and the world of today's virtual environments provides the springboard for an exploration of a wealth of anxieties and dreams, including the construction of identities in an electronically mediated environment, the shifting boundaries between the natural and machine worlds, and the spiritual dimensions of science and technology. In this paper we examine the parallels between the telegraph networks and our current conceptions of cyberspace, as well as unique social and cultural impacts specific to the telegraph. These include the new opportunities and roles available to women in the telegraph industry and the connection between the telegraph and the Spiritualist movement. We discuss the development of the artwork, its structure and aesthetics, and the technical development of the work.

Emission dynamics of InAs/InP quantum-dash laser

KAUST Repository

Khan, Mohammed Zahed Mustafa

2012-01-01

The effect of current pulse width on the lasing spectra of chirp InAs/InP quantum-dash laser is presented. The spectra shows unusual splitting with increasing current injection which is correlated to the active region inhomogeneity.

"To look at death another way": Black teenage males' perspectives on second-lines and regular funerals in New Orleans.

Science.gov (United States)

Bordere, Tashel C

The purpose of this study was to describe how Black adolescent males understand "second-line" (musical processions) and "regular"/traditional funeral rituals in New Orleans following the violent deaths of significant persons in their lives. In-depth interviews were conducted with 10 Black males between the ages of 12 and 15 using descriptive phenomenology methodology. Findings revealed that these participants understood death as a cause for celebration, remembrance, and unity related to their experiences with the second-line ritual. Three elements of the life world of Black teenage males were descriptive of second lines, including: a) observed locations of second lines; b) dancing to good music; and c) observed messages conveyed through t-shirts. Participants provided gender-based descriptions of perceived spoken and unspoken rights in grieving at the two distinct rituals. Related to their second-line experience, the teens reflect on ways in which they wish to have their deaths ritualized.

Low-Intensity Sprint Training With Blood Flow Restriction Improves 100-m Dash.

Science.gov (United States)

Behringer, Michael; Behlau, Daniel; Montag, Johannes C K; McCourt, Molly L; Mester, Joachim

2017-09-01

Behringer, M, Behlau, D, Montag, JCK, McCourt, ML, and Mester, J. Low-intensity sprint training with blood flow restriction improves 100-m dash. J Strength Cond Res 31(9): 2462-2472, 2017-We investigated the effects of practical blood flow restriction (pBFR) of leg muscles during sprint training on the 100-m dash time in well-trained sport students. Participants performed 6 × 100-m sprints at 60-70% of their maximal 100-m sprinting speed twice a week for 6 weeks, either with (intervention group [IG]; n = 12) or without pBFR (control group [CG]; n = 12). The 100-m dash time significantly decreased more in the IG (-0.38 ± 0.24 seconds) than in the CG (-0.16 ± 0.17 seconds). The muscle thickness of the rectus femoris increased only in the IG, whereas no group-by-time interactions were found for the muscle thickness of the biceps femoris and the biceps brachii. The maximal isometric force, measured using a leg press, did not change in either group. However, the rate of force development improved in the IG. Growth hormone, testosterone, insulin-like growth factor 1, and cortisol concentrations did not significantly differ between both groups at any measurement time point (pre, 1 minute, 20 minutes, 120 minutes, and 24 hours after the 6 all-out sprints of the first training session). The muscle damage marker h-FABP increased significantly more in the CG than in the IG. The pBFR improved the 100-m dash time significantly more than low-intensity sprint interval training alone. Other noted benefits of training with pBFR were a decreased level of muscle damage, a greater increase of the rectus femoris muscle thickness, and a higher rate of force development. However, the tested hormones were unable to explain the additional beneficial effects.

Iron line spectroscopy with Einstein-dilaton-Gauss-Bonnet black holes

Science.gov (United States)

Nampalliwar, Sourabh; Bambi, Cosimo; Kokkotas, Kostas D.; Konoplya, Roman A.

2018-06-01

Einstein-dilaton-Gauss-Bonnet gravity is a well-motivated alternative theory of gravity that emerges naturally from string theory. While black hole solutions have been known in this theory in numerical form for a while, an approximate analytical metric was obtained recently by some of us, which allows for faster and more detailed analysis. Here we test the accuracy of the analytical metric in the context of X-ray reflection spectroscopy. We analyze innermost stable circular orbits (ISCO) and relativistically broadened iron lines and find that both the ISCO and iron lines are determined sufficiently accurately up to the limit of the approximation. We also find that, though the ISCO increases by about 7% as dilaton coupling increases from zero to extremal values, the redshift at ISCO changes by less than 1%. Consequently, the shape of the iron line is much less sensitive to the dilaton charge than expected.

A Revised Broad-line Region Radius and Black Hole Mass for the Narrow-line Seyfert 1 NGC 4051

DEFF Research Database (Denmark)

Denney, K. D.; Watson, L. C.; Peterson, B. M.

2009-01-01

) radius and the optical continuum luminosity—the R BLR-L relationship. Our new measurements of the lag time between variations in the continuum and Hß emission line made from spectroscopic monitoring of NGC 4051 lead to a measured BLR radius of R BLR = 1.87+0.54 -0.50 light days and black hole mass of M...

Pain in workers with shoulder impingement syndrome: an assessment using the DASH and McGill pain questionnaires Dor em trabalhadores portadores da síndrome do impacto do ombro: uma avaliação através dos questionários DASH e McGill de dor

Directory of Open Access Journals (Sweden)

PR Camargo

2007-04-01

Full Text Available OBJECTIVE: This study assessed physical function and pain in male and female workers with shoulder impingement syndrome using the Brazilian Portuguese versions of the Disabilities of the Arm, Shoulder and Hand (DASH and McGill pain questionnaires. METHODS: Twenty-seven assembly line workers (18 men and 9 women; mean age of 33.26 ± 6.49 years in the school supply industry were evaluated. The duration of the shoulder impingement pain was 31.74 ± 32.92 months and the amount of time of the workers in this industry was 11.08 ± 6.41 years. The DASH questionnaire was used to evaluate functional status and symptoms of the upper limbs of the workers. Using the McGill Pain Questionnaire, the pain was quantified by the number of words chosen and by the pain rating index (PRI. RESULTS: The women presented higher scores (POBJETIVO: Este estudo avaliou função física e dor em trabalhadores com síndrome do impacto através das versões brasileiras dos questionários "Disabilities of the Arm, Shoulder and Hand" (DASH e McGill de dor. MÉTODO: Vinte e sete trabalhadores (18 homens e 9 mulheres; idade média de 33,26 ± 6,49 anos de uma linha de produção de uma indústria de material escolar foram avaliados. O tempo de duração de dor no ombro era de 31,74 ± 32,92 meses e o tempo de trabalho na indústria era de 11,08 ± 6,41 anos. O questionário DASH foi utilizado para avaliar o estado funcional e os sintomas dos membros superiores dos trabalhadores. Através do questionário McGill de dor, a dor foi quantificada pelo número de palavras escolhidas e pelo índice de classificação da dor (ICD. RESULTADOS: As mulheres apresentaram maiores escores (P< 0,05 que os homens para ambos os módulos do DASH. As mulheres escolheram mais palavras (17,00 ± 2,59 que os homens (13,33 ± 3,16 e também apresentaram o maior ICD total (P< 0,05. CONCLUSÃO: Os resultados obtidos neste grupo de trabalhadores brasileiros com síndrome do impacto do ombro identificam os

Mediterranean diet, Dietary Approaches to Stop Hypertension (DASH) style diet, and metabolic health in U.S. adults.

Science.gov (United States)

Park, Yong-Moon Mark; Steck, Susan E; Fung, Teresa T; Zhang, Jiajia; Hazlett, Linda J; Han, Kyungdo; Lee, Seung-Hwan; Kwon, Hyuk-Sang; Merchant, Anwar T

2017-10-01

There is sparse evidence on the relationship between the Mediterranean diet, Dietary Approaches to Stop Hypertension (DASH) style diet, and metabolic health, especially comparing cardiometabolic phenotypes among in normal weight and obese populations. We aimed to investigate the association of the Mediterranean diet scores (MDS) and DASH index with metabolically healthy obese (MHO) and metabolically obese normal weight (MONW) phenotypes in a representative U.S. MDS and DASH index were calculated using dietary data from 2767 adults aged 20-90 years without any prior diagnosis of cancer or cardiovascular disease from the National Health and Nutrition Examination Survey III, 1988-1994. MHO and MONW individuals were identified using fasting glucose, insulin resistance, blood pressure, triglycerides, C-reactive protein, and high-density lipoprotein-cholesterol. Higher MDS was associated with higher odds of MHO phenotype (odds ratio (OR) T3 vs T1 , 2.57 [95% confidence interval (CI), 1.04-6.35]; P trend = 0.04), and higher DASH index was associated with lower odds of MONW phenotype (OR T3 vs T1, 0.59 [95% CI, 0.38-0.93]; P trend = 0.03) only in the younger age group (Mediterranean diet or DASH style diet was favorably associated with MHO and MONW phenotypes only in the younger age group, suggesting that potential dietary intervention to prevent cardiometabolic disease differ by age group. Published by Elsevier Ltd.

Retarded coordinates based at a world line and the motion of a small black hole in an external universe

International Nuclear Information System (INIS)

Poisson, Eric

2004-01-01

In the first part of this article I present a system of retarded coordinates based at an arbitrary world line of an arbitrary curved spacetime. The retarded-time coordinate labels forward light cones that are centered on the world line, the radial coordinate is an affine parameter on the null generators of these light cones, and the angular coordinates are constant on each of these generators. The spacetime metric in the retarded coordinates is displayed as an expansion in powers of the radial coordinate and expressed in terms of the world line's acceleration vector and the spacetime's Riemann tensor evaluated at the world line. The formalism is illustrated in two examples, the first involving a comoving world line of a spatially flat cosmology, the other featuring an observer in circular motion in the Schwarzschild spacetime. The main application of the formalism is presented in the second part of the article, in which I consider the motion of a small black hole in an empty external universe. I use the retarded coordinates to construct the metric of the small black hole perturbed by the tidal field of the external universe, and the metric of the external universe perturbed by the presence of the black hole. Matching these metrics produces the MiSaTaQuWa equations of motion for the small black hole

The effect of multi active junctions on broadband emission from InAs/InGaAlAs quantum-dash structure

KAUST Repository

Tan, Cheeloon; Djie, Hery Susanto; Tan, C. K.; Hongpinyo, V.; Ding, Yunhsiang; Ooi, Boon S.

2009-01-01

We demonstrate the importance of multi active layer stacking in realizing a semiconductor broadband quantum-dash-in-well laser. The photoluminescence measurements show the negligible factor of largely localized inhomogeneous quantum-dash ensembles in producing ultra-wide envelope of emission. © 2009 IEEE.

The effect of multi active junctions on broadband emission from InAs/InGaAlAs quantum-dash structure

KAUST Repository

Tan, Cheeloon

2009-10-01

We demonstrate the importance of multi active layer stacking in realizing a semiconductor broadband quantum-dash-in-well laser. The photoluminescence measurements show the negligible factor of largely localized inhomogeneous quantum-dash ensembles in producing ultra-wide envelope of emission. © 2009 IEEE.

Sensitiveness of the Constant-Murley’s Shoulder and Quick DASH as an Outcome Measure for Midshaft Clavicle Fracture

Directory of Open Access Journals (Sweden)

R Magetsari

2010-03-01

Full Text Available BACKGROUND: Quick DASH and Constant-Murley’s Shoulder are two valid measuring tools for health status and are useful for patients with a wide variety of upper-extremity complaints; it is sufficiently sensitive to reveal even small changes in function. Objective: To evaluate the sensitivity of Quick DASH and Constant-Murley’s Shoulder as an outcome measurement for midshaft clavicle fracture. METHOD: The study population consisted of 64 patients with a diagnosis of midshaft clavicle fracture based on clinical and radiological criteria. Study design was that of a classic prospective cohort study with measurements at 3 and 6 months following the injury. Evaluation was based on effect size (ES and standardized response means (SRM. RESULT: Both Quick DASH and Constant-Murley’s Shoulder showed high sensitivity (ES: 0.711; SRM: 1.46 and ES: 0.628; SRM: 1.45, respectively. CONCLUSION: Quick DASH was more sensitive than Constant-Murley’s Shoulder in detecting clinical changes on midshaft clavicle fractures at 3 and 6 month following treatment.

Effects of Different Dietary Interventions on Calcitriol, Parathyroid Hormone, Calcium, and Phosphorus: Results from the DASH Trial

Directory of Open Access Journals (Sweden)

Ahmed Hassoon

2018-03-01

Full Text Available The “Dietary Approaches to Stop Hypertension” (DASH diet, rich in fiber and low-fat dairy, effectively lowers blood pressure. DASH’s effect on calcitriol and other markers of bone-mineral metabolism is unknown. This secondary analysis of the DASH trial aimed to determine the effect of dietary patterns on blood concentrations of calcitriol, parathyroid hormone (PTH, ionized calcium, and urinary excretion of calcium and phosphorus. Outcomes were available in 334 participants in the trial. After a 3-week run-in on the control diet, participants were randomized to control, fruits and vegetables (F&V, or DASH diets. Outcomes were assessed at the end of run-in, and during the last week of the intervention period. Mean age of participants was 45.7 ± 10.7 years, 46% female, and 57% African-American. Mean ± Standard Deviation(SD baseline serum concentrations of calcitriol, PTH, and ionized calcium were 37.8 ± 9.2 pg/mL, 46.1 ± 18.5 pg/mL and 5.2 ± 0.23 mg/dL, respectively. Mean (±SD urinary calcium and phosphorus excretions were 150.1 ± 77.8 and 708.0 ± 251.8 mg/24 h, respectively. Compared with control, DASH reduced calcitriol −3.32 pg/mL (p = 0.004. Otherwise, there was no significant effect on other biomarkers. DASH lowered serum calcitriol perhaps more among African-Americans. These results raise important questions about the interpretation and clinical significance of low calcitriol concentrations in the setting of recommended diets.

On the Calculation of the Fe K-alpha Line Emissivity of Black Hole Accretion Disks

Energy Technology Data Exchange (ETDEWEB)

Krawczynski, H.; Beheshtipour, B., E-mail: krawcz@wustl.edu [Physics Department and McDonnell Center for the Space Sciences, Washington University in St. Louis, 1 Brookings Drive, CB 1105, St. Louis, MO 63130 (United States)

2017-11-01

Observations of the fluorescent Fe K α emission line from the inner accretion flows of stellar mass black holes in X-ray binaries and supermassive black holes in active galactic nuclei have become an important tool to study the magnitude and inclination of the black hole spin, and the structure of the accretion flow close to the event horizon of the black hole. Modeling spectral, timing, and soon also X-ray polarimetric observations of the Fe K α emission requires the calculation of the specific intensity in the rest frame of the emitting plasma. We revisit the derivation of the equation used for calculating the illumination of the accretion disk by the corona. We present an alternative derivation leading to a simpler equation, and discuss the relation to previously published results.

Orientation dependent emission properties of columnar quantum dash laser structures

NARCIS (Netherlands)

Hein, S.; Podemski, P.; Sek, G.; Misiewicz, J.; Ridha, P.; Fiore, A.; Patriarche, G.; Höfling, S.; Forchel, A.

2009-01-01

InAs columnar quantum dash (CQDash) structures on (100) InP have been realized by gas source molecular beam epitaxy for stacking numbers of up to 24. Laser devices show low threshold current densities between 0.73 and 3.5 kA/ cm2, dependent on the CQDash orientation within the cavity.

Influence of vertical coupling on the lasing operation of quantum-dash laser

KAUST Repository

Khan, Mohammed Zahed Mustafa

2012-01-01

The authors numerically investigated the consequence of vertical coupling among multi-stack InAs quantum dash (Qdash) laser structure on the lasing bandwidth. The developed model is based on multi-population carrier-photon rate equation and incorporates inhomogeneous broadening due to dash size or composition fluctuation, homogeneous broadening of optical gain, and the multi-longitudinal photon modes. In addition, the effect of Qdash layers emitting at different wavelength, and the carrier coupling (tunneling) between adjacent stacks, are also accounted for. The results predict a direct relation between the lasing bandwidth and the barrier thickness and hence enhanced lasing bandwidth could be achieved by decoupling the Qdash layers (large barrier thickness). Moreover, the model further affirms the non-equilibrium distribution of carriers among Qdash layers in a multi-stack laser structure.

Influence of vertical coupling on the lasing operation of quantum-dash laser

KAUST Repository

Khan, Mohammed Zahed Mustafa; Ng, Tien Khee; Ooi, Boon S.

2012-01-01

The authors numerically investigated the consequence of vertical coupling among multi-stack InAs quantum dash (Qdash) laser structure on the lasing bandwidth. The developed model is based on multi-population carrier-photon rate equation

Using iron line reverberation and spectroscopy to distinguish Kerr and non-Kerr black holes

Energy Technology Data Exchange (ETDEWEB)

Jiang, Jiachen; Bambi, Cosimo [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 220 Handan Road, 200433 Shanghai (China); Steiner, James F., E-mail: jcjiang12@fudan.edu.cn, E-mail: bambi@fudan.edu.cn, E-mail: jsteiner@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2015-05-01

The iron Kα line commonly observed in the X-ray spectrum of both stellar-mass and supermassive black hole candidates is produced by the illumination of a cold accretion disk by a hot corona. In this framework, the activation of a new flaring region in the hot corona imprints a time variation on the iron line spectrum. Future X-ray facilities with high time resolution and large effective areas may be able to measure the so-called 2-dimensional transfer function; that is, the iron line profile detected by a distant observer as a function of time in response to an instantaneous flare from the X-ray primary source. This work is a preliminary study to determine if and how such a technique can provide more information about the spacetime geometry around the compact object than the already possible measurements of the time-integrated iron line profile. Within our simplified model, we find that a measurement of iron line reverberation can improve constraints appreciably given a sufficiently strong signal, though that most of the information is present in the time-integrated spectrum. Our aim is to test the Kerr metric. We find that current X-ray facilities and data are unable to provide strong tests of the Kerr nature of supermassive black hole candidates. We consider an optimistic case of 10{sup 5} iron line photons from a next-generation data set. With such data, the reverberation model improves upon the spectral constraint by an order of magnitude.

Dietary approach to stop hypertension (DASH: diet components may be related to lower prevalence of different kinds of cancer: A review on the related documents

Directory of Open Access Journals (Sweden)

Shokouh Onvani

2015-01-01

Full Text Available Background: Dietary approaches to stop hypertension (DASH eating plan is a healthy dietary pattern. Our object is to review surveys in the field of major components of DASH diet and different kinds of cancers. Materials and Methods: Our search result from PubMed search engine recruited to find related articles. Results: Adherence to the DASH diet components was significantly related to lower prevalence of various cancers due to their high content of fiber, nutrients, vitamins, mineral, and antioxidant capacity. Conclusion: In this review, positive association of DASH diet components and different cancers were observed. However, the exact association of DASH with cancers should be clarified in future longitudinal studies due to potential interaction among foods and nutrients.

Carrier relaxation dynamics in InAs/InGaAlAs quantum dashes

KAUST Repository

Ryasnyanskiy, A.I.; Biaggio, I.; Djie, Hery Susanto; Ooi, Boon S.; Tan, C.L.

2011-01-01

We characterize size-dependent carrier relaxation dynamics of partial laser structures containing quantum dashes by time-resolved degenerate four wave mixing between 1.2 and 1.6 ?m. © 2010 Elsevier B.V. All rights reserved.

Carrier relaxation dynamics in InAs/InGaAlAs quantum dashes

KAUST Repository

Ryasnyanskiy, A.I.

2011-03-01

We characterize size-dependent carrier relaxation dynamics of partial laser structures containing quantum dashes by time-resolved degenerate four wave mixing between 1.2 and 1.6 ?m. © 2010 Elsevier B.V. All rights reserved.

Effects of Dietary Approaches to Stop Hypertension (DASH Eating Plan on Inflammation and Liver Functional Tests among Type 2 Diabetic Patients

Directory of Open Access Journals (Sweden)

Leila Azadbakht

2012-04-01

Full Text Available Background: Considering that the new cardiovascular risk factors are important among type 2 diabetes. We evaluated the effects of the Dietary Approaches to Stop Hypertension (DASH eating pattern on inflammation and novel cardiovascular risk factors in type 2 diabetic patients.Materials and Method: In this eight-weeks crossover randomized clinical trail, 31 type 2 diabetic patients were on a control diet or the DASH diet. Fruits, vegetables, whole grains, low-fat dairy products are consumed in high amounts in this diet. However, saturated fat, total fat, cholesterol, refined grains, and sweets are recommended in low amounts. DASH diet had a total of 2,400 mg sodium per day. There was a four week washout between two trial phases. C-reactive protein level, coagulation indices and hepatic function tests were measured at baseline and after each phase of trial.Results: The mean percent change for plasma C-reactive protein level was -26.9±3.5% after the DASH diet and-5.1±3.8% after the control diet (p=0.001. Both alanine aminotransferase and aspartate aminotransferase levels were significantly reduced after consuming the DASH diet compared to the control diet (-14.8±3.0 % vs -6.6±3.4%; p=0.001, -29.4±3.7% vs -5.9±1.4%; p=0.001, respectively. The DASH diet reduced the plasma fibrinogen level compared to the control diet (-11.4±3.6% and 0.5±3.4%; p=0.03, respectively. Conclusion: Among diabetic patients, the DASH diet can play an important role in reducing inflammation, plasma levels of fibrinogen and liver aminotranferases. Future long-term studies are recommended.

Measurements of gain and index dynamics in quantum dash semiconductor optical amplifiers

DEFF Research Database (Denmark)

Poel, Mike van der; Berg, Tommy Winther; Mørk, Jesper

2004-01-01

Ultrafast gain and index recovery of a 1.5um quantum dash amplifier after short pulse amplification is measured using pump-probe spectroscopy. The major part of the gain reduction is found to recover within a few picoseconds....

Predictive value of the DASH tool for predicting return to work of injured workers with musculoskeletal disorders of the upper extremity.

Science.gov (United States)

Armijo-Olivo, Susan; Woodhouse, Linda J; Steenstra, Ivan A; Gross, Douglas P

2016-12-01

To determine whether the Disabilities of the Arm, Shoulder, and Hand (DASH) tool added to the predictive ability of established prognostic factors, including patient demographic and clinical outcomes, to predict return to work (RTW) in injured workers with musculoskeletal (MSK) disorders of the upper extremity. A retrospective cohort study using a population-based database from the Workers' Compensation Board of Alberta (WCB-Alberta) that focused on claimants with upper extremity injuries was used. Besides the DASH, potential predictors included demographic, occupational, clinical and health usage variables. Outcome was receipt of compensation benefits after 3 months. To identify RTW predictors, a purposeful logistic modelling strategy was used. A series of receiver operating curve analyses were performed to determine which model provided the best discriminative ability. The sample included 3036 claimants with upper extremity injuries. The final model for predicting RTW included the total DASH score in addition to other established predictors. The area under the curve for this model was 0.77, which is interpreted as fair discrimination. This model was statistically significantly different than the model of established predictors alone (pmodels (p=0.34). The DASH tool together with other established predictors significantly helped predict RTW after 3 months in participants with upper extremity MSK disorders. An appealing result for clinicians and busy researchers is that DASH item 23 has equal predictive ability to the total DASH score. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Motion Coordination and Adaptation Using Deception and Human Interactions

Science.gov (United States)

2016-11-18

compared to those obtained by the closed form solution of the LQR if the maximizing control was not present (black dashed lines). Findeisen , D. Flockerzi, U...Brenner, R. Findeisen , D. Flockerzi, U. Reichl, and K. Sundmacher (Eds.), Birkhauser, pp. 199-224, 2015. J.P. de la Croix and M. Egerstedt. A Control

Effects of Different Conditioning Activities on 100-m Dash Performance in High School Track and Field Athletes.

Science.gov (United States)

Ferreira-Júnior, João B; Guttierres, Ana P M; Encarnação, Irismar G A; Lima, Jorge R P; Borba, Diego A; Freitas, Eduardo D S; Bemben, Michael G; Vieira, Carlos A; Bottaro, Martim

2018-01-01

This study compared the effects of different conditioning activities on the 100-m dash performance of 11 male, high school track and field athletes (mean age = 16.3; SD = 1.2 years). Participants performed a 100-m dash seven minutes after each of four randomized conditioning protocols, with each condition and 100-m dash separated by 3-10 days. The conditioning protocols were (a) control, no conditioning activity; (b) weighted plyometric, three sets of 10 repetitions of alternate leg bounding with additional load of 10% of the body mass; (c) free sprint, two 20-m sprints; and (d) resisted sprint (RS), two 20-m resisted sprints using an elastic tubing tool. We obtained session ratings of perceived exertion (SRPE) immediately after each conditioning protocol. There were no significant differences between any of the three experimental conditioning activities on 100-m sprint time, but the RS protocol improved 100-m sprint time compared with the control (no conditioning) protocol ( p < .001). The RS also led to greater sprint velocity and higher SRPE compared with the control condition ( p < .01). There was no significant association between SRPE and 100-m performance ( p = .77, r = .05). These results suggest a benefit for young male track and field athletes to the elastic tubing warm-up activities prior to the 100-m dash.

Supraclavicular scalenectomy for thoracic outlet syndrome--functional outcomes assessed using the DASH scoring system.

LENUS (Irish Health Repository)

Glynn, Ronan W

2012-02-01

To evaluate supraclavicular scalenectomy ± cervical rib excision for thoracic outlet syndrome (TOS), employing Disability of Arm, Shoulder, and Hand (DASH) scoring for functional assessment post-decompression.

Distinct Lasing Operation From Chirped InAs/InP Quantum-Dash Laser

KAUST Repository

Khan, Mohammed Zahed Mustafa; Ng, Tien Khee; Lee, Chi-Sen; Anjum, Dalaver H.; Cha, Dong Kyu; Bhattacharya, Pallab K.; Ooi, Boon S.

2013-01-01

We study the enhanced inhomogeneity across the InAs quantum-dash (Qdash) layers by incorporating a chirped AlGaInAs barrier thickness in the InAs/InP laser structure. The lasing operation is investigated via Fabry-Pérot ridge-waveguide laser

CONSTRAINTS ON BLACK HOLE GROWTH, QUASAR LIFETIMES, AND EDDINGTON RATIO DISTRIBUTIONS FROM THE SDSS BROAD-LINE QUASAR BLACK HOLE MASS FUNCTION

International Nuclear Information System (INIS)

Kelly, Brandon C.; Hernquist, Lars; Siemiginowska, Aneta; Vestergaard, Marianne; Fan Xiaohui; Hopkins, Philip

2010-01-01

We present an estimate of the black hole mass function of broad-line quasars (BLQSOs) that self-consistently corrects for incompleteness and the statistical uncertainty in the mass estimates, based on a sample of 9886 quasars at 1 1 it is highly incomplete at M BH ∼ 9 M sun and L/L Edd ∼ BL > 150 ± 15 Myr for black holes at z = 1 with a mass of M BH = 10 9 M sun , and we constrain the maximum mass of a black hole in a BLQSO to be ∼3 x 10 10 M sun . Our estimated distribution of BLQSO Eddington ratios peaks at L/L Edd ∼ 0.05 and has a dispersion of ∼0.4 dex, implying that most BLQSOs are not radiating at or near the Eddington limit; however, the location of the peak is subject to considerable uncertainty. The steep increase in number density of BLQSOs toward lower Eddington ratios is expected if the BLQSO accretion rate monotonically decays with time. Furthermore, our estimated lifetime and Eddington ratio distributions imply that the majority of the most massive black holes spend a significant amount of time growing in an earlier obscured phase, a conclusion which is independent of the unknown obscured fraction. These results are consistent with models for self-regulated black hole growth, at least for massive systems at z > 1, where the BLQSO phase occurs at the end of a fueling event when black hole feedback unbinds the accreting gas, halting the accretion flow.

Racial Fault-lines in “Baseball’s Great Experiment:” Black Perceptions, White Reactions

Directory of Open Access Journals (Sweden)

Henry D. Fetter

2012-06-01

Full Text Available This paper examines three facets of the breaking of major league baseball’s color line by Jackie Robinson of the Brooklyn Dodgers in 1947: the perception of blacks, the response of white players (whether teammates or opponents, and the reaction of baseball fans. By so doing, the paper will illuminate the fault-lines that characterized race relations within both the sport of baseball and the larger society as each was confronted with new challenges to long established policies and practices in the years after the Second World War.

The association of the dietary approach to stop hypertension (DASH) diet with blood pressure, glucose and lipid profiles in Malaysian and Philippines populations.

Science.gov (United States)

Tiong, X T; Nursara Shahirah, A; Pun, V C; Wong, K Y; Fong, A Y Y; Sy, R G; Castillo-Carandang, N T; Nang, E E K; Woodward, M; van Dam, R M; Tai, E S; Venkataraman, K

2018-05-07

Despite a growing body of evidence from Western populations on the health benefits of Dietary Approaches to Stop Hypertension (DASH) diets, their applicability in South East Asian settings is not clear. We examined cross-sectional associations between DASH diet and cardio-metabolic risk factors among 1837 Malaysian and 2898 Philippines participants in a multi-national cohort. Blood pressures, fasting lipid profile and fasting glucose were measured, and DASH score was computed based on a 22-item food frequency questionnaire. Older individuals, women, those not consuming alcohol and those undertaking regular physical activity were more likely to have higher DASH scores. In the Malaysian cohort, while total DASH score was not significantly associated with cardio-metabolic risk factors after adjusting for confounders, significant associations were observed for intake of green vegetable [0.011, standard error (SE): 0.004], and red and processed meat (-0.009, SE: 0.004) with total cholesterol. In the Philippines cohort, a 5-unit increase in total DASH score was significantly and inversely associated with systolic blood pressure (-1.41, SE: 0.40), diastolic blood pressure (-1.09, SE: 0.28), total cholesterol (-0.015, SE: 0.005), low-density lipoprotein cholesterol (-0.025, SE: 0.008), and triglyceride (-0.034, SE: 0.012) after adjusting for socio-demographic and lifestyle groups. Intake of milk and dairy products, red and processed meat, and sugared drinks were found to significantly associated with most risk factors. Differential associations of DASH diet and dietary components with cardio-metabolic risk factors by country suggest the need for country-specific tailoring of dietary interventions to improve cardio-metabolic risk profiles. Copyright © 2018 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by

Investigation of Chirped InAs/InGaAlAs/InP Quantum Dash Lasers as Broadband Emitters

KAUST Repository

Khan, Mohammed Zahed Mustafa

2014-02-01

In this paper, we assessed the effect of additionally broadened quantum dash (Qdash) optical transitions in the multi-stack dash-in-a-well laser structure at both, material and device level. A broad photoluminescence linewidth of ?150 nm demonstrates the formation of highly inhomogeneous InAs-dashes across the stacks. The transmission electron microscopy revealed small (large) average dash height from the Qdash stack with thick (thin) over grown barrier layer. The Fabry-Perot laser diodes fabricated from this chirped structure exhibits unique device physics under the short pulsewidth (SPW) and quasi-continuous wave (QCW) operation. Varying the ridge-width W from 2 to 4 ?rm showed quenching of ultrabroad lasing signature in the SPW operation, and consistent even for a wide 15 ?rm oxide strip laser diode. A lasing spectral split with reduced intensity gap in the center is observed in the QCW operation with the gap decreasing with increasing ridge-width. Such atypical lasing operation, influenced by the waveguiding mechanism is qualitatively realized by associating to the reduced vertical coupling effect of the Qdash stacks in the operation of small ridge-width lasers compared with large ridge-width and oxide stripe lasers, and leading to varying non-uniform distribution of carriers among the inhomogeneously broadened Qdash stacks in each case. Our chirped 2 × 830 ?rm ridge laser demonstrated marked improvement in the internal quantum efficiency (?80) and -3 dB lasing bandwidth, >50 nm centered at ?1.61 ?m. © 2013 IEEE.

Reprocessing of Soft X-ray Emission Lines in Black Hole Accretion Disks

International Nuclear Information System (INIS)

Mauche, C W; Liedahl, D A; Mathiesen, B F; Jimenez-Garate, M A; Raymond, J C

2003-01-01

By means of a Monte Carlo code that accounts for Compton scattering and photoabsorption followed by recombination, we have investigated the radiation transfer of Lyα, Heα, and recombination continua photons of H- and He-like C, N, O, and Ne produced in the photoionized atmosphere of a relativistic black hole accretion disk. We find that photoelectric opacity causes significant attenuation of photons with energies above the O VIII K-edge; that the conversion efficiencies of these photons into lower-energy lines and recombination continua are high; and that accounting for this reprocessing significantly (by factors of 21% to 105%) increases the flux of the Lyα and Heα emission lines of H- and He-like C and O escaping the disk atmosphere

Spectral Analysis of Quantum-Dash Lasers: Effect of Inhomogeneous Broadening of the Active-Gain Region

KAUST Repository

Khan, Mohammed Zahed Mustafa

2012-05-01

The effect of the active region inhomogeneity on the spectral characteristics of InAs/InP quantum-dash (Qdash) lasers is examined theoretically by solving the coupled set of carrier-photon rate equations. The inhomogeneity due to dash size or composition fluctuation is included in the model by considering dispersive energy states and characterized by a Gaussian envelope. In addition, the technique incorporates multilongitudinal photon modes and homogeneous broadening of the optical gain. The results predict a red shift in the central lasing wavelength of Qdash lasers on increasing the inhomogeneous broadening either explicitly or implicitly, which supports various experimental observations. The threshold current density and the lasing bandwidth are also found to increase. © 2012 IEEE.

Spectral Analysis of Quantum-Dash Lasers: Effect of Inhomogeneous Broadening of the Active-Gain Region

KAUST Repository

Khan, Mohammed Zahed Mustafa; Ng, Tien Khee; Ooi, Boon S.; Schwingenschlö gl, Udo

2012-01-01

The effect of the active region inhomogeneity on the spectral characteristics of InAs/InP quantum-dash (Qdash) lasers is examined theoretically by solving the coupled set of carrier-photon rate equations. The inhomogeneity due to dash size or composition fluctuation is included in the model by considering dispersive energy states and characterized by a Gaussian envelope. In addition, the technique incorporates multilongitudinal photon modes and homogeneous broadening of the optical gain. The results predict a red shift in the central lasing wavelength of Qdash lasers on increasing the inhomogeneous broadening either explicitly or implicitly, which supports various experimental observations. The threshold current density and the lasing bandwidth are also found to increase. © 2012 IEEE.

The Increasing British Climate Ambitiousness: A Mere Reflection of ''The Dash for Gas''?

International Nuclear Information System (INIS)

Wetterstad, Joergen; Butenschoen, Siri Hals

2000-01-01

The authors ask three main questions: First, why were the initial British climate positions more on the reluctant side? Second, why did the British climate positions become more ambitious towards the mid-1990s? And third, why the rapid, seemingly doubling of reduction ambitiousness in the spring of 1997? These questions are addressed in turn: First, with regard to the initial British climate reluctance, although ''malign'' emissions projections and related high potential reduction costs played a significant role, political and cultural factors must clearly be drawn into the picture. Secondly, increasing ambitiousness from the mid-1990s was largely a reflection of the dash-for-gas factor. Thirdly, although the stepped-up ambitiousness in 1997 was, of course, underpinned by the dash-for-gas process, other factors, such as the new Labour Government coming into office, need also to be taken into account here. (author)

Testing the Kerr black hole hypothesis: Comparison between the gravitational wave and the iron line approaches

Energy Technology Data Exchange (ETDEWEB)

Cárdenas-Avendaño, Alejandro [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Programa de Matemática, Fundación Universitaria Konrad Lorenz, 110231 Bogotá (Colombia); Jiang, Jiachen [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Bambi, Cosimo, E-mail: bambi@fudan.edu.cn [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Theoretical Astrophysics, Eberhard-Karls Universität Tübingen, 72076 Tübingen (Germany)

2016-09-10

The recent announcement of the detection of gravitational waves by the LIGO/Virgo Collaboration has opened a new window to test the nature of astrophysical black holes. Konoplya & Zhidenko have shown how the LIGO data of GW 150914 can constrain possible deviations from the Kerr metric. In this letter, we compare their constraints with those that can be obtained from accreting black holes by fitting their X-ray reflection spectrum, the so-called iron line method. We simulate observations with eXTP, a next generation X-ray mission, finding constraints much stronger than those obtained by Konoplya & Zhidenko. Our results can at least show that, contrary to what is quite commonly believed, it is not obvious that gravitational waves are the most powerful approach to test strong gravity. In the presence of high quality data and with the systematics under control, the iron line method may provide competitive constraints.

[Drug Addiction Self-Help Recovery scale (DASH-scale): an approach to the measurement of recovery from drug addiction in self-help program among drug addicts].

Science.gov (United States)

Shimane, Takuya; Misago, Chizuru

2004-12-01

The purpose of the study was to develop a scale for measuring the recovery in self-help program for drug addicts. Our study sites were fourteen self-help groups for drug addicts called "DARC: Drug Addiction Rehabilitation Center". DARC activities were based on Narcotics Anonymous types of self-help program. The 25-items DASH-scale questionnaire was developed using data, which were obtained through in-depth interview among DARC staff. A cross-sectional study among recovering addicts participating in "DARC" activities was implemented from Jan 2004 to Feb 2004. 164 subjects were responded to our questionnaire. Factor analysis was carried out and items with weaker or split loadings were removed. Factor analysis of DASH-scale results produced a surprisingly clean four-factor solution. 19-items were left to form the final DASH-scale; regular life-style (6 items), acceptance of drug addiction (5 items), sympathy with member (5 items), reborn (3 items). The internal consistency (Cronbach's Alpha) of these scales was very high (0.87). Low but significant concurrent correlations were observed between the DASH-scale and the Rosenberg Self-Esteem Scale (0.22), Purpose in Life Test (0.35). Discriminant validity of the DASH-scale was supported by significant increase with exposed period of self-help program. Evidence supports the DASH-scale was possible to measure recovery in self-help program.

Delivering stable high-quality video: an SDN architecture with DASH assisting network elements

NARCIS (Netherlands)

J.W.M. Kleinrouweler (Jan Willem); S. Cabrero Barros (Sergio); P.S. Cesar Garcia (Pablo Santiago)

2016-01-01

textabstractDynamic adaptive streaming over HTTP (DASH) is a simple, but effective, technology for video streaming over the Internet. It provides adaptive streaming while being highly scalable at the side of the content providers. However, the mismatch between TCP and the adaptive bursty nature of

Numerically investigating the cause of broadband lasing from InAs/InP quantum-dash laser

KAUST Repository

Khan, Mohammed Zahed Mustafa

2013-01-01

The authors numerically investigated the origin of broadband lasing from multi-stack InAs/InP quantum dash (Qdash) laser. For this a model based on multi-population carrier-photon rate equation is developed which treats each Qdash stacking layer separately. In addition, the coupling between the adjacent stacks is also accounted in the model apart from the inhomogeneous broadening due to dash size or composition fluctuation. Simulation results show that the effect of Qdash inhomogeneity on a single plane (in-plane or localized inhomogeneity) is negligible in broadening the lasing spectra compared to the inhomogeneity across the stacks that are emitting at different wavelength. Our results would help in further optimizing the wafer structure design and improve the lasing bandwidth.

Adherence to Dietary Approaches to Stop Hypertension (DASH) Dietary Pattern in Relation to Chronic Obstructive Pulmonary Disease (COPD): A Case-Control Study.

Science.gov (United States)

Ardestani, Mohammad Emami; Onvani, Shokouh; Esmailzadeh, Ahmad; Feizi, Awat; Azadbakht, Leila

2017-01-01

This case-control study was designed to investigate the association between adherences to the Dietary Approaches to Stop Hypertension (DASH) diet in patients with chronic obstructive pulmonary disease (COPD) in comparison to subjects without COPD. This is a case-control study. Usual dietary intake was assessed using a validated food frequency questionnaire. Lung function was evaluated with spirometry testing, and one of the researchers inquired about other respiratory symptoms, including chronic cough, sputum, and breathlessness. Adherence to the DASH dietary pattern was assessed according to the Fung method. This study was conducted at Alzahra University Hospital of Isfahan, Iran, in 2015. Eight-four patients with COPD and 80 subjects without a history of COPD participated in study. The mean age of participants was 57 years. Average smoking in the case group was about 27.5 pack-years. Spirometry tests including forced expiratory volume in 1 second (FEV 1 ), forced vital capacity (FVC), and FEV 1 /FVC were significantly lower in patients with COPD (p = 0.0001). Among COPD symptoms, cough was significantly decreased across tertiles of DASH score (p = 0.03). Significant differences were found for DASH score between patients with COPD and control subjects (19.82 + 3.63 vs 21.13 + 3.82, p = 0.02). Vitamin C, vitamin E, and dietary fiber intake were lower in patients with COPD (144.32 + 70.51 vs 166.97 + 71.88, p = 0.04, 7.49 + 3.91 vs 8.72 + 3.21, p = 0.02 and 19.34 + 7.05 vs 22.19 + 7.87, p = 0.01, respectively). We observed that adherence to a DASH dietary pattern among patients with COPD was significantly lower compared to the control group. Cough was significantly decreased by increments in adherence to a DASH dietary pattern.

Scalable privacy-preserving data sharing methodology for genome-wide association studies: an application to iDASH healthcare privacy protection challenge.

Science.gov (United States)

Yu, Fei; Ji, Zhanglong

2014-01-01

In response to the growing interest in genome-wide association study (GWAS) data privacy, the Integrating Data for Analysis, Anonymization and SHaring (iDASH) center organized the iDASH Healthcare Privacy Protection Challenge, with the aim of investigating the effectiveness of applying privacy-preserving methodologies to human genetic data. This paper is based on a submission to the iDASH Healthcare Privacy Protection Challenge. We apply privacy-preserving methods that are adapted from Uhler et al. 2013 and Yu et al. 2014 to the challenge's data and analyze the data utility after the data are perturbed by the privacy-preserving methods. Major contributions of this paper include new interpretation of the χ2 statistic in a GWAS setting and new results about the Hamming distance score, a key component for one of the privacy-preserving methods.

Hairy black hole stability in AdS, quantum mechanics on the half-line and holography

International Nuclear Information System (INIS)

Anabalón, Andrés; Astefanesei, Dumitru; Oliva, Julio

2015-01-01

We consider the linear stability of 4-dimensional hairy black holes with mixed boundary conditions in Anti-de Sitter spacetime. We focus on the mass of scalar fields around the maximally supersymmetric vacuum of the gauged N=8 supergravity in four dimensions, m"2=−2l"−"2. It is shown that the Schrödinger operator on the half-line, governing the S"2, H"2 or ℝ"2 invariant mode around the hairy black hole, allows for non-trivial self-adjoint extensions and each of them corresponds to a class of mixed boundary conditions in the gravitational theory. Discarding the self-adjoint extensions with a negative mode impose a restriction on these boundary conditions. The restriction is given in terms of an integral of the potential in the Schrödinger operator resembling the estimate of Simon for Schrödinger operators on the real line. In the context of AdS/CFT duality, our result has a natural interpretation in terms of the field theory dual effective potential.

Hairy black hole stability in AdS, quantum mechanics on the half-line and holography

Energy Technology Data Exchange (ETDEWEB)

Anabalón, Andrés [Departamento de Ciencias, Facultad de Artes Liberales yFacultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez,Av. Padre Hurtado 750, Viña del Mar (Chile); Astefanesei, Dumitru [Instituto de Física, Pontificia Universidad Católica de Valparaíso,Casilla 4059, Valparaíso (Chile); Oliva, Julio [Departamento de Física, Universidad de Concepción,Casilla 160-C, Concepción (Chile)

2015-10-09

We consider the linear stability of 4-dimensional hairy black holes with mixed boundary conditions in Anti-de Sitter spacetime. We focus on the mass of scalar fields around the maximally supersymmetric vacuum of the gauged N=8 supergravity in four dimensions, m{sup 2}=−2l{sup −2}. It is shown that the Schrödinger operator on the half-line, governing the S{sup 2}, H{sup 2} or ℝ{sup 2} invariant mode around the hairy black hole, allows for non-trivial self-adjoint extensions and each of them corresponds to a class of mixed boundary conditions in the gravitational theory. Discarding the self-adjoint extensions with a negative mode impose a restriction on these boundary conditions. The restriction is given in terms of an integral of the potential in the Schrödinger operator resembling the estimate of Simon for Schrödinger operators on the real line. In the context of AdS/CFT duality, our result has a natural interpretation in terms of the field theory dual effective potential.

Silhouette and spectral line profiles in the special modification of the Kerr black hole geometry generated by quintessential fields

Energy Technology Data Exchange (ETDEWEB)

Schee, Jan; Stuchlik, Zdenek [Silesian University in Opava, Faculty of Philosophy and Science, Institute of Physics and Research Centre for Theoretical Physics and Astrophysics, Opava (Czech Republic)

2016-11-15

We study optical effects in quintessential Kerr black hole spacetimes corresponding to the limiting case of the equation-of-state parameter ω{sub q} = -1/3 of the quintessence. In dependence on the dimensionless quintessential field parameter c, we determine the black hole silhouette and the spectral line profiles of Keplerian disks generated in this special quintessential Kerr geometry, representing an extension of the general modifications of the Kerr geometry introduced recently by Ghasemi-Nodehi and Bambi (Eur. Phys. J. C 56:290, 2016). We demonstrate that due to the influence of the parameter c, the silhouette is almost homogeneously enlarged, and the spectral line profiles are redshifted with almost conserved shape. (orig.)

Tailoring the photoluminescence polarization anisotropy of a single InAs quantum dash by a post-growth modification of its dielectric environment

Energy Technology Data Exchange (ETDEWEB)

Mrowiński, P.; Misiewicz, J.; Sęk, G. [Laboratory for Optical Spectroscopy of Nanostructures, Division of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wrocław (Poland); Tarnowski, K.; Olszewski, J.; Urbańczyk, W. [Division of Optics and Photonics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wrocław (Poland); Somers, A.; Kamp, M. [Technische Physik & W. C. Röntgen-Center for Complex Material Systems, Universität Würzburg, Würzburg Germany (Germany); Reithmaier, J. P. [Institute of Nanostructure Technologies and Analytics (INA), CINSaT, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel (Germany); Machnikowski, P. [Division of Theoretical Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wrocław (Poland)

2016-08-21

Excitonic emission from single InAs/InGaAlAs/InP quantum dashes has been investigated in terms of controlling the polarization anisotropy by altering the shape of the processed sub-micrometer mesa structures. Photoluminescence has been measured from exemplary single quantum dashes emitting around 1.3 and 1.55 μm and placed inside rectangular mesas of various orientation, asymmetry, and sizes. The detected degree of linear polarization of bright exciton emission ranges from −0.1 to ca. 0.55, compared to 0.25 for dashes in unaltered or isotropic in-plane dielectric surrounding. These results are interpreted by numerical simulations using an emitter coupled with a single optical mode in such a mesa and outgoing in the direction normal to the sample surface.

Characteristics of quantum dash laser under the rate equation model framework

KAUST Repository

Khan, Mohammed Zahed Mustafa

2010-09-01

The authors present a numerical model to study the carrier dynamics of InAs/InP quantum dash (QDash) lasers. The model is based on single-state rate equations, which incorporates both, the homogeneous and the inhomogeneous broadening of lasing spectra. The numerical technique also considers the unique features of the QDash gain medium. This model has been applied successfully to analyze the laser spectra of QDash laser. ©2010 IEEE.

Are the patient-rated wrist evaluation (PRWE) and the disabilities of the arm, shoulder and hand (DASH) questionnaire used in distal radial fractures truly valid and reliable?

Science.gov (United States)

Krol, R. G.; Bhandari, M.; Goslings, J. C.; Poolman, R. W.; Scholtes, V. A. B.

2018-01-01

Objectives The patient-rated wrist evaluation (PRWE) and the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire are patient-reported outcome measures (PROMs) used for clinical and research purposes. Methodological high-quality clinimetric studies that determine the measurement properties of these PROMs when used in patients with a distal radial fracture are lacking. This study aimed to validate the PRWE and DASH in Dutch patients with a displaced distal radial fracture (DRF). Methods The intraclass correlation coefficient (ICC) was used for test-retest reliability, between PROMs completed twice with a two-week interval at six to eight months after DRF. Internal consistency was determined using Cronbach’s α for the dimensions found in the factor analysis. The measurement error was expressed by the smallest detectable change (SDC). A semi-structured interview was conducted between eight and 12 weeks after DRF to assess the content validity. Results A total of 119 patients (mean age 58 years (sd 15)), 74% female, completed PROMs at a mean time of six months (sd 1) post-fracture. One overall meaningful dimension was found for the PRWE and the DASH. Internal consistency was excellent for both PROMs (Cronbach’s α 0.96 (PRWE) and 0.97 (DASH)). Test-retest reliability was good for the PRWE (ICC 0.87) and excellent for the DASH (ICC 0.91). The SDC was 20 for the PRWE and 14 for the DASH. No floor or ceiling effects were found. The content validity was good for both questionnaires. Conclusion The PRWE and DASH are valid and reliable PROMs in assessing function and disability in Dutch patients with a displaced DRF. However, due to the high SDC, the PRWE and DASH are less useful for individual patients with a distal radial fracture in clinical practice. Cite this article: Y. V. Kleinlugtenbelt, R. G. Krol, M. Bhandari, J. C. Goslings, R. W. Poolman, V. A. B. Scholtes. Are the patient-rated wrist evaluation (PRWE) and the disabilities of the arm, shoulder and

Constraints on Black Hole Spin in a Sample of Broad Iron Line AGN

Science.gov (United States)

Brenneman, Laura W.; Reynolds, Christopher S.

2008-01-01

We present a uniform X-ray spectral analysis of nine type-1 active galactic nuclei (AGN) that have been previously found to harbor relativistically broadened iron emission lines. We show that the need for relativistic effects in the spectrum is robust even when one includes continuum "reflection" from the accretion disk. We then proceed to model these relativistic effects in order to constrain the spin of the supermassive black holes in these AGN. Our principal assumption, supported by recent simulations of geometrically-thin accretion disks, is that no iron line emission (or any associated Xray reflection features) can originate from the disk within the innermost stable circular orbit. Under this assumption, which tends to lead to constraints in the form of lower limits on the spin parameter, we obtain non-trivial spin constraints on five AGN. The spin parameters of these sources range from moderate (a approximates 0.6) to high (a > 0.96). Our results allow, for the first time, an observational constraint on the spin distribution function of local supermassive black holes. Parameterizing this as a power-law in dimensionless spin parameter (f(a) varies as absolute value of (a) exp zeta), we present the probability distribution for zeta implied by our results. Our results suggest 90% and 95% confidence limits of zeta > -0.09 and zeta > -0.3 respectively.

The Dietary Approaches to Stop Hypertension (DASH) diet, Western diet, and risk of gout in men: prospective cohort study.

Science.gov (United States)

Rai, Sharan K; Fung, Teresa T; Lu, Na; Keller, Sarah F; Curhan, Gary C; Choi, Hyon K

2017-05-09

Objective  To prospectively examine the relation between the Dietary Approaches to Stop Hypertension (DASH) and Western diets and risk of gout (ie, the clinical endpoint of hyperuricemia) in men. Design  Prospective cohort study. Setting  The Health Professionals Follow-up Study. Participants  44 444 men with no history of gout at baseline. Using validated food frequency questionnaires, each participant was assigned a DASH dietary pattern score (based on high intake of fruits, vegetables, nuts and legumes, low fat dairy products, and whole grains, and low intake of sodium, sweetened beverages, and red and processed meats) and a Western dietary pattern score (based on high intake of red and processed meats, French fries, refined grains, sweets, and desserts). Main outcome measure  Risk of incident gout meeting the preliminary American College of Rheumatology survey criteria for gout, adjusting for potential confounders, including age, body mass index, hypertension, diuretic use, and alcohol intake. Results  During 26 years of follow-up, 1731 confirmed cases of incident gout were documented. A higher DASH dietary pattern score was associated with a lower risk for gout (adjusted relative risk for extreme fifths 0.68, 95% confidence interval 0.57 to 0.80, P value for trend dietary pattern score was associated with an increased risk for gout (1.42, 1.16 to 1.74, P=0.005). Conclusion  The DASH diet is associated with a lower risk of gout, suggesting that its effect of lowering uric acid levels in individuals with hyperuricemia translates to a lower risk of gout. Conversely, the Western diet is associated with a higher risk of gout. The DASH diet may provide an attractive preventive dietary approach for men at risk of gout. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Factors Influencing Cryptocurrency Prices: Evidence from Bitcoin, Ethereum, Dash, Litcoin, and Monero

Directory of Open Access Journals (Sweden)

Yhlas Sovbetov

2018-02-01

Full Text Available This paper examines factors that influence prices of most common five cryptocurrencies such Bitcoin, Ethereum, Dash, Litecoin, and Monero over 2010-2018 using weekly data. The study employs ARDL technique and documents several findings. First, cryptomarket-related factors such as market beta, trading volume, and volatility appear to be significant determinant for all five cryptocurrencies both in short- and long-run. Second, attractiveness of cryptocurrencies also matters in terms of their price determination, but only in long-run. This indicates that formation (recognition of the attractiveness of cryptocurrencies are subjected to time factor. In other words, it travels slowly within the market. Third, SP500 index seems to have weak positive long-run impact on Bitcoin, Ethereum, and Litcoin, while its sign turns to negative losing significance in short-run, except Bitcoin that generates an estimate of -0.20 at 10% significance level. Lastly, error-correction models for Bitcoin, Etherem, Dash, Litcoin, and Monero show that cointegrated series cannot drift too far apart, and converge to a long-run equilibrium at a speed of 23.68%, 12.76%, 10.20%, 22.91%, and 14.27% respectively.

Numerically investigating the cause of broadband lasing from InAs/InP quantum-dash laser

KAUST Repository

Khan, Mohammed Zahed Mustafa; Ng, Tien Khee; Ooi, Boon S.

2013-01-01

The authors numerically investigated the origin of broadband lasing from multi-stack InAs/InP quantum dash (Qdash) laser. For this a model based on multi-population carrier-photon rate equation is developed which treats each Qdash stacking layer

10-GHz 1.59-μm quantum dash passively mode-locked two-section lasers

DEFF Research Database (Denmark)

Dontabactouny, Madhoussoudhana; Rosenberg, C.; Semenova, Elizaveta

2010-01-01

This paper reports the fabrication and the characterisation of a 10 GHz two-section passively mode-locked quantum dash laser emitting at 1.59 μm. The potential of the device's mode-locking is investigated through an analytical model taking into account both the material parameters and the laser...

EMISSION SIGNATURES FROM SUB-PARSEC BINARY SUPERMASSIVE BLACK HOLES. I. DIAGNOSTIC POWER OF BROAD EMISSION LINES

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Khai; Bogdanović, Tamara [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta GA 30332 (United States)

2016-09-10

Motivated by advances in observational searches for sub-parsec supermassive black hole binaries (SBHBs) made in the past few years, we develop a semi-analytic model to describe spectral emission-line signatures of these systems. The goal of this study is to aid the interpretation of spectroscopic searches for binaries and to help test one of the leading models of binary accretion flows in the literature: SBHB in a circumbinary disk. In this work, we present the methodology and a comparison of the preliminary model with the data. We model SBHB accretion flows as a set of three accretion disks: two mini-disks that are gravitationally bound to the individual black holes and a circumbinary disk. Given a physically motivated parameter space occupied by sub-parsec SBHBs, we calculate a synthetic database of nearly 15 million broad optical emission-line profiles and explore the dependence of the profile shapes on characteristic properties of SBHBs. We find that the modeled profiles show distinct statistical properties as a function of the semimajor axis, mass ratio, eccentricity of the binary, and the degree of alignment of the triple disk system. This suggests that the broad emission-line profiles from SBHB systems can in principle be used to infer the distribution of these parameters and as such merit further investigation. Calculated profiles are more morphologically heterogeneous than the broad emission lines in observed SBHB candidates and we discuss improved treatment of radiative transfer effects, which will allow a direct statistical comparison of the two groups.

EMISSION SIGNATURES FROM SUB-PARSEC BINARY SUPERMASSIVE BLACK HOLES. I. DIAGNOSTIC POWER OF BROAD EMISSION LINES

International Nuclear Information System (INIS)

Nguyen, Khai; Bogdanović, Tamara

2016-01-01

Motivated by advances in observational searches for sub-parsec supermassive black hole binaries (SBHBs) made in the past few years, we develop a semi-analytic model to describe spectral emission-line signatures of these systems. The goal of this study is to aid the interpretation of spectroscopic searches for binaries and to help test one of the leading models of binary accretion flows in the literature: SBHB in a circumbinary disk. In this work, we present the methodology and a comparison of the preliminary model with the data. We model SBHB accretion flows as a set of three accretion disks: two mini-disks that are gravitationally bound to the individual black holes and a circumbinary disk. Given a physically motivated parameter space occupied by sub-parsec SBHBs, we calculate a synthetic database of nearly 15 million broad optical emission-line profiles and explore the dependence of the profile shapes on characteristic properties of SBHBs. We find that the modeled profiles show distinct statistical properties as a function of the semimajor axis, mass ratio, eccentricity of the binary, and the degree of alignment of the triple disk system. This suggests that the broad emission-line profiles from SBHB systems can in principle be used to infer the distribution of these parameters and as such merit further investigation. Calculated profiles are more morphologically heterogeneous than the broad emission lines in observed SBHB candidates and we discuss improved treatment of radiative transfer effects, which will allow a direct statistical comparison of the two groups.

The Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH can measure the impairment, activity limitations and participation restriction constructs from the International Classification of Functioning, Disability and Health (ICF

Directory of Open Access Journals (Sweden)

McQueen Margaret

2008-08-01

Full Text Available Abstract Background The International Classification of Functioning, Disability and Health (ICF model of the consequences of disease identifies three health outcomes, impairment, activity limitations and participation restrictions. However, few orthopaedic health outcome measures were developed with reference to the ICF. This study examined the ability of a valid and frequently used measure of upper limb function, namely the Disabilities of the Arm, Shoulder and Hand Questionnaire (DASH, to operationalise the ICF. Methods Twenty-four judges used the method of Discriminant Content Validation to allocate the 38 items of the DASH to the theoretical definition of one or more ICF outcome. One-sample t-tests classified each item as measuring, impairment, activity limitations, participation restrictions, or a combination thereof. Results The DASH contains items able to measure each of the three ICF outcomes with discriminant validity. The DASH contains five pure impairment items, 19 pure activity limitations items and three participation restriction items. In addition, seven items measured both activity limitations and participation restrictions. Conclusion The DASH can measure the three health outcomes identified by the ICF. Consequently the DASH could be used to examine the impact of trauma and subsequent interventions on each health outcome in the absence of measurement confound.

Dipeptidyl peptidase-IV activity and/or structure homologues (DASH) in transformed neuroectodermal cells

Czech Academy of Sciences Publication Activity Database

Malík, Radek; Bušek, P.; Mareš, Vladislav; Ševčík, J.; Kleibl, Z.; Šedo, A.

2003-01-01

Roč. 524, - (2003), s. 95-102 ISSN 0065-2598. [International Conference on Dipeptidyl Aminopeptidases. Berlin, 26.09.2002-28.09.2002] R&D Projects: GA ČR GA301/02/0962 Grant - others:GA UK(CZ) 7/2002/C Institutional research plan: CEZ:AV0Z5011922 Keywords : DASH molecules * DPP-IV activity * glioma cells Subject RIV: FD - Oncology ; Hematology

Unlocking the black box: line managers and HRM performance in a call centre context

OpenAIRE

Harney, Brian; Jordan, Claire

2008-01-01

Purpose – The purpose of this paper is to show the way to unlock the black box of HRM and performance linkages by exploring one of the key variables that mediates the link, namely whether line managers can stimulate improvements in firm performance by eliciting appropriate employee outcomes in a call centre context. Design/methodology/approach – The research draws on Purcell's "People-Performance Model" as a sensitising framework to inform an in-depth case study of a call centre. This pro...

Constraining The Abundance Of Massive Black Hole Binaries By Spectroscopic Monitoring Of Quasars With Offset Broad Emission Lines

Science.gov (United States)

Liu, Xin; Shen, Y.

2012-05-01

A fraction of quasars have long been known to show significant bulk velocity offsets (of a few hundred to thousands of km/s) in the broad permitted emission lines with respect to host galaxy systemic redshift. Various scenarios may explain these features such as massive black hole binaries or broad line region gas kinematics. As previously demonstrated by the dedicated work of Eracleous and colleagues, long-term spectroscopic monitoring provides a promising test to discriminate between alternative scenarios. Here, we present a sample of 300 shifted-line quasars homogeneously selected from the SDSS DR7. For 60 of them, we have conducted second-epoch optical spectra using MMT/BCS, ARC 3.5m/DIS, and/or FLWO 1.5m/FAST. These new observations, combined with the existing SDSS spectra, enable us to constrain the velocity drifts of these shifted broad lines with time baselines of a few years up to a decade. Previous work has been focusing on objects with extreme velocity offsets: > 1000 km/s. Our work extends to the parameter space of smaller velocity offsets, where larger velocity drifts would be expected in the binary scenario. Our results may be used to identify strong candidates for and to constrain the abundance of massive black hole binaries, which are expected in the hierarchical universe, but have so far been illusive.

Effect of active medium inhomogeneity on lasing characteristics of InAs/InP quantum-dash lasers

KAUST Repository

Khan, Mohammed Zahed Mustafa; Ng, Tien Khee; Ooi, Boon S.; Schwingenschlö gl, Udo

2010-01-01

The authors report on the effect of quantum-dash (Qdash) inhomogeneity on the characteristics of InAs/InP Qdash laser utilizing a single state rate equation model. The inhomogeneity is assumed to follow the Gaussian approximation. From our

A Modification of the Fuzzy Logic Based DASH Adaptation Scheme for Performance Improvement

Directory of Open Access Journals (Sweden)

Hyun Jun Kim

2018-01-01

Full Text Available We propose a modification of the fuzzy logic based DASH adaptation scheme (FDASH for seamless media service in time-varying network conditions. The proposed scheme (mFDASH selects a more appropriate bit-rate for the next segment by modification of the Fuzzy Logic Controller (FLC and estimates more accurate available bandwidth than FDASH scheme by using History-Based TCP Throughput Estimation. Moreover, mFDASH reduces the number of video bit-rate changes by applying Segment Bit-Rate Filtering Module (SBFM and employs Start Mechanism for clients to provide high-quality videos in the very beginning stage of the streaming service. Lastly, Sleeping Mechanism is applied to avoid any expected buffer overflow. We then use NS-3 Network Simulator to verify the performance of mFDASH. Upon the experimental results, mFDASH shows no buffer overflow within the limited buffer size, which is not guaranteed in FDASH. Also, we confirm that mFDASH provides the highest QoE to DASH clients among the three schemes (mFDASH, FDASH, and SVAA in Point-to-Point networks, Wi-Fi networks, and LTE networks, respectively.

Construct validity, test-retest reliability and internal consistency of the Thai version of the disabilities of the arm, shoulder and hand questionnaire (DASH-TH) in patients with carpal tunnel syndrome.

Science.gov (United States)

Buntragulpoontawee, Montana; Phutrit, Suphatha; Tongprasert, Siam; Wongpakaran, Tinakon; Khunachiva, Jeeranan

2018-03-27

This study evaluated additional psychometric properties of the Thai version of the disabilities of the arm, shoulder and hand questionnaire (DASH-TH) which included, test-retest reliability, construct validity, internal consistency of in patients with carpal tunnel syndrome. As for determining construct validity, the Thai EuroQOL questionnaire (EQ-5D-5L) was also administered in order to examine convergent and divergent validity. Fifty patients completed both questionnaires. The DASH-TH showed excellent test-retest reliability (intraclass correlation coefficient = 0.811) and internal consistency (Cronbach's alpha = 0.911). The exploratory factor analysis yielded a six-factor solution while the confirmatory factor analysis denoted that the hypothesized model adequately fit the data with a comparative fit index of 0.967 and a Tucker-Lewis index of 0.964. The related subscales between the DASH-TH and the Thai EQ-5D-5L were significantly correlated, indicating the DASH-TH's convergent and discriminant validity. The DASH-TH demonstrated good reliability, internal consistency construct validity, and multidimensionality, in assessing the upper extremity function in carpal tunnel syndrome patients.

Ultrafast gain and index dynamics of quantum dash structures emitting at 1.55 mu m

DEFF Research Database (Denmark)

Poel, Mike van der; Mørk, Jesper; Somers, A.

2006-01-01

The authors systematically characterize the ultrafast gain and index recovery of a quantum dash semiconductor optical amplifier after it has amplified a strong femtosecond pulse. The results show a recovery dominated by a fast time constant of 1.4 ps with an ultimate recovery taking place on a 150...

Comparison of 4 established DASH diet indexes: examining associations of index scores and colorectal cancer.

Science.gov (United States)

Miller, Paige E; Cross, Amanda J; Subar, Amy F; Krebs-Smith, Susan M; Park, Yikyung; Powell-Wiley, Tiffany; Hollenbeck, Albert; Reedy, Jill

2013-09-01

Multiple diet indexes have been developed to capture the Dietary Approaches to Stop Hypertension (DASH) dietary pattern and examine relations with health outcomes but have not been compared within the same study population to our knowledge. We compared 4 established DASH indexes and examined associations with colorectal cancer. Scores were generated from a food-frequency questionnaire in the NIH-AARP Diet and Health Study (n = 491,841). Separate indexes defined by Dixon (7 food groups, saturated fat, and alcohol), Mellen (9 nutrients), Fung (7 food groups and sodium), and Günther (8 food groups) were used. HRs and 95% CIs for colorectal cancer were generated by using Cox proportional hazard models. From 1995 through 2006, 6752 incident colorectal cancer cases were ascertained. In men, higher scores were associated with reduced colorectal cancer incidence by comparing highest to lowest quintiles for all indexes as follows: Dixon (HR: 0.77; 95% CI: 0.69, 0.87), Mellen (HR: 0.78; 95% CI: 0.71, 0.86), Fung (HR: 0.75; 95% CI: 0.68, 0.83), and Günther (HR: 0.81; 95% CI: 0.74, 0.90). Higher scores in women were inversely associated with colorectal cancer incidence by using methods defined by Mellen (HR: 0.79; 95% CI: 0.68, 0.91), Fung (HR: 0.84; 95% CI: 0.73, 0.96), and Günther (HR: 0.84; 95% CI: 0.73.0.97) but not Dixon (HR: 1.01; 95% CI: 0.80, 1.28). The consistency in findings, particularly in men, suggests that all indexes capture an underlying construct inherent in the DASH dietary pattern, although the specific index used can affect results.

Dash Cam videos on YouTube™ offer insights into factors related to moose-vehicle collisions.

Science.gov (United States)

Rea, Roy V; Johnson, Chris J; Aitken, Daniel A; Child, Kenneth N; Hesse, Gayle

2018-03-26

To gain a better understanding of the dynamics of moose-vehicle collisions, we analyzed 96 videos of moose-vehicle interactions recorded by vehicle dash-mounted cameras (Dash Cams) that had been posted to the video-sharing website YouTube™. Our objective was to determine the effects of road conditions, season and weather, moose behavior, and driver response to actual collisions compared to near misses when the collision was avoided. We identified 11 variables that were consistently observable in each video and that we hypothesized would help to explain a collision or near miss. The most parsimonious logistic regression model contained variables for number of moose, sight time, vehicle slows, and vehicle swerves (AIC c w = 0.529). This model had good predictive accuracy (AUC = 0.860, SE = 0.041). The only statistically significant variable from this model that explained the difference between moose-vehicle collisions and near misses was 'Vehicle slows'. Our results provide no evidence that road surface conditions (dry, wet, ice or snow), roadside habitat type (forested or cleared), the extent to which roadside vegetation was cleared, natural light conditions (overcast, clear, twilight, dark), season (winter, spring and summer, fall), the presence of oncoming traffic, or the direction from which the moose entered the roadway had any influence on whether a motorist collided with a moose. Dash Cam videos posted to YouTube™ provide a unique source of data for road safety planners trying to understand what happens in the moments just before a moose-vehicle collision and how those factors may differ from moose-vehicle encounters that do not result in a collision. Copyright © 2018 Elsevier Ltd. All rights reserved.

THE LICK AGN MONITORING PROJECT: BROAD-LINE REGION RADII AND BLACK HOLE MASSES FROM REVERBERATION MAPPING OF Hβ

International Nuclear Information System (INIS)

Bentz, Misty C.; Walsh, Jonelle L.; Barth, Aaron J.; Baliber, Nairn; Bennert, Vardha Nicola; Greene, Jenny E.; Hidas, Marton G.; Canalizo, Gabriela; Hiner, Kyle D.; Filippenko, Alexei V.; Ganeshalingam, Mohan; Lee, Nicholas; Li, Weidong; Serduke, Frank J. D.; Silverman, Jeffrey M.; Steele, Thea N.; Gates, Elinor L.; Malkan, Matthew A.; Minezaki, Takeo; Sakata, Yu

2009-01-01

We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3-m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z 6 -10 7 M sun and also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to allow for a time lag to be measured between the continuum fluctuations and the response to these fluctuations in the broad Hβ emission. We present here the light curves for all the objects in this sample and the subsequent Hβ time lags for the nine objects where these measurements were possible. The Hβ lag time is directly related to the size of the broad-line region (BLR) in AGNs, and by combining the Hβ lag time with the measured width of the Hβ emission line in the variable part of the spectrum, we determine the virial mass of the central supermassive black hole in these nine AGNs. The absolute calibration of the black hole masses is based on the normalization derived by Onken et al., which brings the masses determined by reverberation mapping into agreement with the local M BH -σ * relationship for quiescent galaxies. We also examine the time lag response as a function of velocity across the Hβ line profile for six of the AGNs. The analysis of four leads to rather ambiguous results with relatively flat time lags as a function of velocity. However, SBS 1116+583A exhibits a symmetric time lag response around the line center reminiscent of simple models for circularly orbiting BLR clouds, and Arp 151 shows an asymmetric profile that is most easily explained by a simple gravitational infall model. Further investigation will be necessary to fully understand the constraints placed on the physical models of the BLR by the velocity-resolved response in these objects.

DETERMINING QUASAR BLACK HOLE MASS FUNCTIONS FROM THEIR BROAD EMISSION LINES: APPLICATION TO THE BRIGHT QUASAR SURVEY

International Nuclear Information System (INIS)

Kelly, Brandon C.; Fan Xiaohui; Vestergaard, Marianne

2009-01-01

We describe a Bayesian approach to estimating quasar black hole mass functions (BHMF) using the broad emission lines to estimate black hole mass. We show how using the broad-line mass estimates in combination with statistical techniques developed for luminosity function estimation (e.g., the 1/V a correction) leads to statistically biased results. We derive the likelihood function for the BHMF based on the broad-line mass estimates, and derive the posterior distribution for the BHMF, given the observed data. We develop our statistical approach for a flexible model where the BHMF is modeled as a mixture of Gaussian functions. Statistical inference is performed using Markov chain Monte Carlo (MCMC) methods, and we describe a Metropolis-Hastings algorithm to perform the MCMC. The MCMC simulates random draws from the probability distribution of the BHMF parameters, given the data, and we use a simulated data set to show how these random draws may be used to estimate the probability distribution for the BHMF. In addition, we show how the MCMC output may be used to estimate the probability distribution of any quantities derived from the BHMF, such as the peak in the space density of quasars. Our method has the advantage that it is able to constrain the BHMF even beyond the survey detection limits at the adopted confidence level, accounts for measurement errors and the intrinsic uncertainty in broad-line mass estimates, and provides a natural way of estimating the probability distribution of any quantities derived from the BHMF. We conclude by using our method to estimate the local active BHMF using the z BH ∼> 10 8 M sun . Our analysis implies that at a given M BH , z < 0.5 broad-line quasars have a typical Eddington ratio of ∼0.4 and a dispersion in Eddington ratio of ∼<0.5 dex.

FIRST LONG-TERM OPTICAL SPECTRAL MONITORING OF A BINARY BLACK HOLE CANDIDATE E1821+643. I. VARIABILITY OF SPECTRAL LINES AND CONTINUUM

International Nuclear Information System (INIS)

Shapovalova, A. I.; Burenkov, A. N.; Zhdanova, V. E.; Popović, L. Č.; Chavushyan, V. H.; Valdés, J. R.; Patiño-Álvarez, V.; León-Tavares, J.; Torrealba, J.; Ilić, D.; Kovačević, A.; Kollatschny, W.

2016-01-01

We report the results of the first long-term (1990–2014) optical spectrophotometric monitoring of a binary black hole candidate QSO E1821+643, a low-redshift, high-luminosity, radio-quiet quasar. In the monitored period, the continua and Hγ fluxes changed about two times, while the Hβ flux changed about 1.4 times. We found periodical variations in the photometric flux with periods of 1200, 1850, and 4000 days, and 4500-day periodicity in the spectroscopic variations. However, the periodicity of 4000–4500 days covers only one cycle of variation and should be confirmed with a longer monitoring campaign. There is an indication of the period around 1300 days in the spectroscopic light curves, buts with small significance level, while the 1850-day period could not be clearly identified in the spectroscopic light curves. The line profiles have not significantly changed, showing an important red asymmetry and broad line peak redshifted around +1000 km s −1 . However, Hβ shows a broader mean profile and has a larger time lag (τ ∼ 120 days) than Hγ (τ ∼ 60 days). We estimate that the mass of the black hole is ∼2.6 × 10 9 M ⊙ . The obtained results are discussed in the frame of the binary black hole hypothesis. To explain the periodicity in the flux variability and high redshift of the broad lines, we discuss a scenario where dense, gas-rich, cloudy-like structures are orbiting around a recoiling black hole

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.

Recent Updates to SWANFAR (registered trademark), a 5DVAR Data Assimilation System for SWAN

Science.gov (United States)

2016-11-10

inside surf zone. Blue, red, and black lines illustrate heights of small, medium, and large waves as they approach shore (from right to left). If...small, medium, or large offshore waves. Only assimilation from outside the surf zone (such as within the dashed box region) will accu- rately reflect...involv- ing a systematic and consistent examination of much larger global wave datasets and many more model simulations at global , regional, and local

Dieta DASH na redução dos níveis de pressão arterial e prevenção do acidente vascular cerebral = DASH diet in reducing blood pressure and preventing stroke

Directory of Open Access Journals (Sweden)

Piper, Vanessa Alves

2012-01-01

Conclusões: As evidências disponíveis sugerem que modificações no estilo de vida, incluindo a adoção de uma dieta tipo DASH, são estratégias eficazes no controle da hipertensão arterial e na redução de eventos cardiovasculares, como o acidente vascular cerebral

Modeling the lasing spectra of InAs/InP Quantum dash lasers

KAUST Repository

Khan, Mohammed Zahed Mustafa; Bhattacharya, Pallab K.; Ng, Tien Khee; Ooi, Boon S.; Schwingenschlö gl, Udo

2011-01-01

We report a theoretical model for InAs/InP quantum-dash (Qdash) lasers incorporating a coupled set of rate equations taking into account the inhomogeneous broadening due to Qdash size fluctuation, the homogeneous broadening due to optical gain of a single Qdash, and the longitudinal cavity modes. The role of cavity length on the Qdash lasing characteristics, particularly the redshift in the peak lasing wavelength, is analyzed and compared with the experimental results by attributing it to the active region inhomogeneity.

Modeling the lasing spectra of InAs/InP Quantum dash lasers

KAUST Repository

Khan, Mohammed Zahed Mustafa

2011-03-09

We report a theoretical model for InAs/InP quantum-dash (Qdash) lasers incorporating a coupled set of rate equations taking into account the inhomogeneous broadening due to Qdash size fluctuation, the homogeneous broadening due to optical gain of a single Qdash, and the longitudinal cavity modes. The role of cavity length on the Qdash lasing characteristics, particularly the redshift in the peak lasing wavelength, is analyzed and compared with the experimental results by attributing it to the active region inhomogeneity.

REDSHIFT EVOLUTION IN BLACK HOLE-BULGE RELATIONS: TESTING C IV-BASED BLACK HOLE MASSES

International Nuclear Information System (INIS)

Greene, Jenny E.; Peng, Chien Y.; Ludwig, Randi R.

2010-01-01

We re-examine claims for redshift evolution in black hole-bulge scaling relations based on lensed quasars. In particular, we refine the black hole (BH) mass estimates using measurements of Balmer lines from near-infrared spectroscopy obtained with Triplespec at Apache Point Observatory. In support of previous work, we find a large scatter between Balmer and UV line widths, both Mg IIλλ2796, 2803 and C IVλλ1548, 1550. There is tentative evidence that C III]λ1909, despite being a blend of multiple transitions, may correlate well with Mg II, although a larger sample is needed for a real calibration. Most importantly, we find no systematic changes in the estimated BH masses for the lensed sample based on Balmer lines, providing additional support to the interpretation that black holes were overly massive compared to their host galaxies at high redshift.

Evidence for Broad-Line Region Outflows and Their Impact on Black Hole Mass Measurements

DEFF Research Database (Denmark)

Denney, K. D.; Assef, R. J.; Horne, K.

2012-01-01

could not be fully and accurately interpreted from the 1D velocity-resolved reverberation signal. From the VDM, an outflow component to the emission remains possible but appears to be in addition to an underlying, disk-like BLR structure consistent in size with the measured reverberation lag. The black...... hole (BH) mass derived from this data is therefore secure from any uncertainties possibly derived from gravitationally unbound gas contributing to the emission. Additionally, we demonstrate that BLR emission from the C IV ¿1549 broad emission line can reliably be used as a virial BH mass estimator...

A RADIAL VELOCITY TEST FOR SUPERMASSIVE BLACK HOLE BINARIES AS AN EXPLANATION FOR BROAD, DOUBLE-PEAKED EMISSION LINES IN ACTIVE GALACTIC NUCLEI

Energy Technology Data Exchange (ETDEWEB)

Liu, Jia; Halpern, Jules P. [Astronomy Department, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Eracleous, Michael [Department of Astronomy and Institute for Gravitation and The Cosmos, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

2016-01-20

One of the proposed explanations for the broad, double-peaked Balmer emission lines observed in the spectra of some active galactic nuclei (AGNs) is that they are associated with sub-parsec supermassive black hole (SMBH) binaries. Here, we test the binary broad-line region hypothesis through several decades of monitoring of the velocity structure of double-peaked Hα emission lines in 13 low-redshift, mostly radio-loud AGNs. This is a much larger set of objects compared to an earlier test by Eracleous et al. and we use much longer time series for the three objects studied in that paper. Although systematic changes in radial velocity can be traced in many of their lines, they are demonstrably not like those of a spectroscopic binary in a circular orbit. Any spectroscopic binary period must therefore be much longer than the span of the monitoring (assuming a circular orbit), which in turn would require black hole masses that exceed by 1–2 orders of magnitude the values obtained for these objects using techniques such as reverberation mapping and stellar velocity dispersion. Moreover, the response of the double-peaked Balmer line profiles to fluctuations of the ionizing continuum and the shape of the Lyα profiles are incompatible with an SMBH binary. The binary broad-line region hypothesis is therefore disfavored. Other processes evidently shape these line profiles and cause the long-term velocity variations of the double peaks.

A method of coupling the Paternò-Büchi reaction with direct infusion ESI-MS/MS for locating the C[double bond, length as m-dash]C bond in glycerophospholipids.

Science.gov (United States)

Stinson, Craig A; Xia, Yu

2016-06-21

Tandem mass spectrometry (MS/MS) coupled with soft ionization is established as an essential platform for lipid analysis; however, determining high order structural information, such as the carbon-carbon double bond (C[double bond, length as m-dash]C) location, remains challenging. Recently, our group demonstrated a method for sensitive and confident lipid C[double bond, length as m-dash]C location determination by coupling online the Paternò-Büchi (PB) reaction with nanoelectrospray ionization (nanoESI) and MS/MS. Herein, we aimed to expand the scope of the PB reaction for lipid analysis by enabling the reaction with infusion ESI-MS/MS at much higher flow rates than demonstrated in the nanoESI setup (∼20 nL min(-1)). In the new design, the PB reaction was effected in a fused silica capillary solution transfer line, which also served as a microflow UV reactor, prior to ESI. This setup allowed PB reaction optimization and kinetics studies. Under optimized conditions, a maximum of 50% PB reaction yield could be achieved for a standard glycerophosphocholine (PC) within 6 s of UV exposure over a wide flow rate range (0.1-10 μL min(-1)). A solvent composition of 7 : 3 acetone : H2O (with 1% acid or base modifier) allowed the highest PB yields and good lipid ionization, while lower yields were obtained with an addition of a variety of organic solvents. Radical induced lipid peroxidation was identified to induce undesirable side reactions, which could be effectively suppressed by eliminating trace oxygen in the solution via N2 purge. Finally, the utility of coupling the PB reaction with infusion ESI-MS/MS was demonstrated by analyzing a yeast polar lipid extract where C[double bond, length as m-dash]C bond locations were revealed for 35 glycerophospholipids (GPs).

Black Hole Mass Estimation in Type 1 AGN: Hβ vs. Mg II Lines and the Role of Balmer Continuum

Energy Technology Data Exchange (ETDEWEB)

Kovačević-Dojčinović, Jelena [Astronomical Observatory, Belgrade (Serbia); Marčeta-Mandić, Sladjana; Popović, Luka Č., E-mail: sladjana@aob.rs [Astronomical Observatory, Belgrade (Serbia); Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia)

2017-07-24

Here we investigate the Hβ and Mg II spectral line parameters used for the black hole mass (M{sub BH}) estimation for a sample of Type 1 Active Galactic Nuclei (AGN) spectra selected from the Sloan Digital Sky Survey (SDSS) database. We have analyzed and compared the virialization of the Hβ and Mg II emission lines, and found that the Hβ line is more confident virial estimator than Mg II. We have investigated the influence of the Balmer continuum emission to the M{sub BH} estimation from the UV parameters, and found that the Balmer continuum emission can contribute to the overestimation of the M{sub BH} on average for ~5% (up to 10%).

Borehole radar as a tool to optimise mine layouts and production

CSIR Research Space (South Africa)

Mafiri, MT

2008-11-01

Full Text Available (from exploration drilling and geological mapping) used to build the reef topography (red dots). The black dashed lines represent the positions of the raises 6 4.3 Financial benefits of using borehole radar The financial benefits... by drilling would require more drill holes (assuming the holes are at an angle to the reef). Overall borehole radar greatly outweighed the high costs of drilling and directional surveying, and much improved the knowledge about the geological model...

Comparison of 4 established DASH diet indexes: examining associations of index scores and colorectal cancer123

Science.gov (United States)

Cross, Amanda J; Subar, Amy F; Krebs-Smith, Susan M; Park, Yikyung; Powell-Wiley, Tiffany; Hollenbeck, Albert; Reedy, Jill

2013-01-01

Background: Multiple diet indexes have been developed to capture the Dietary Approaches to Stop Hypertension (DASH) dietary pattern and examine relations with health outcomes but have not been compared within the same study population to our knowledge. Objective: We compared 4 established DASH indexes and examined associations with colorectal cancer. Design: Scores were generated from a food-frequency questionnaire in the NIH-AARP Diet and Health Study (n = 491,841). Separate indexes defined by Dixon (7 food groups, saturated fat, and alcohol), Mellen (9 nutrients), Fung (7 food groups and sodium), and Günther (8 food groups) were used. HRs and 95% CIs for colorectal cancer were generated by using Cox proportional hazard models. Results: From 1995 through 2006, 6752 incident colorectal cancer cases were ascertained. In men, higher scores were associated with reduced colorectal cancer incidence by comparing highest to lowest quintiles for all indexes as follows: Dixon (HR: 0.77; 95% CI: 0.69, 0.87), Mellen (HR: 0.78; 95% CI: 0.71, 0.86), Fung (HR: 0.75; 95% CI: 0.68, 0.83), and Günther (HR: 0.81; 95% CI: 0.74, 0.90). Higher scores in women were inversely associated with colorectal cancer incidence by using methods defined by Mellen (HR: 0.79; 95% CI: 0.68, 0.91), Fung (HR: 0.84; 95% CI: 0.73, 0.96), and Günther (HR: 0.84; 95% CI: 0.73.0.97) but not Dixon (HR: 1.01; 95% CI: 0.80, 1.28). Conclusion: The consistency in findings, particularly in men, suggests that all indexes capture an underlying construct inherent in the DASH dietary pattern, although the specific index used can affect results. PMID:23864539

Validity of the Mania Subscale of the Diagnostic Assessment for the Severely Handicapped-II (DASH-II).

Science.gov (United States)

Matson, Johnny L.; Smiroldo, Brandi B.

1997-01-01

A study tested the validity of the Diagnostic Assessment for the Severely Handicapped-II (DASH-II) for determining the presence of mania (bipolar disorder) in 22 individuals with severe mental retardation. Results found the mania subscale to be internally consistent and able to be used to classify manic and control subjects accurately. (Author/CR)

BLACK HOLE MASS ESTIMATES AND RAPID GROWTH OF SUPERMASSIVE BLACK HOLES IN LUMINOUS z ∼ 3.5 QUASARS

Energy Technology Data Exchange (ETDEWEB)

Zuo, Wenwen; Wu, Xue-Bing [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China); Fan, Xiaohui; Green, Richard [Steward Observatory, The University of Arizona, Tucson, AZ 85721 (United States); Wang, Ran [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Bian, Fuyan [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston ACT 2611 (Australia)

2015-02-01

We present new near-infrared (IR) observations of the Hβ λ4861 and Mg II λ2798 lines for 32 luminous quasars with 3.2 < z < 3.9 using the Palomar Hale 200 inch telescope and the Large Binocular Telescope. We find that the Mg II FWHM is well correlated with the Hβ FWHM, confirming itself as a good substitute for the Hβ FWHM in the black hole mass estimates. The continuum luminosity at 5100 Å well correlates with the continuum luminosity at 3000 Å and the broad emission line luminosities (Hβ and Mg II). With simultaneous near-IR spectroscopy of the Hβ and Mg II lines to exclude the influences of flux variability, we are able to evaluate the reliability of estimating black hole masses based on the Mg II line for high redshift quasars. With the reliable Hβ line based black hole mass and Eddington ratio estimates, we find that the z ∼ 3.5 quasars in our sample have black hole masses 1.90 × 10{sup 9} M {sub ☉} ≲ M {sub BH} ≲ 1.37 × 10{sup 10} M {sub ☉}, with a median of ∼5.14 × 10{sup 9} M {sub ☉} and are accreting at Eddington ratios between 0.30 and 3.05, with a median of ∼1.12. Assuming a duty cycle of 1 and a seed black hole mass of 10{sup 4} M {sub ☉}, we show that the z ∼ 3.5 quasars in this sample can grow to their estimated black hole masses within the age of the universe at their redshifts.

Theoretical observation of two state lasing from InAs/InP quantum-dash lasers

KAUST Repository

Khan, Mohammed Zahed Mustafa

2011-09-01

The effect of cavity length on the lasing wavelength of InAs/InP quantum dash (Qdash) laser is examined using the carrier-photon rate equation model including the carrier relaxation process from the Qdash ground state and excited state. Both, homogeneous and inhomogeneous broadening has been incorporated in the model. We show that ground state lasing occurs with longer cavity lasers and excited state lasing occurs from relatively short cavity lasers. © 2011 IEEE.

SIMULTANEOUS ULTRAVIOLET AND OPTICAL EMISSION-LINE PROFILES OF QUASARS: IMPLICATIONS FOR BLACK HOLE MASS DETERMINATION

International Nuclear Information System (INIS)

Ho, Luis C.; Dong Xiaobo; Goldoni, Paolo; Ponti, Gabriele; Greene, Jenny E.

2012-01-01

The X-shooter instrument on the Very Large Telescope was used to obtain spectra of seven moderate-redshift quasars simultaneously covering the spectral range ∼3000 Å to 2.5 μm. At z ≈ 1.5, most of the prominent broad emission lines in the ultraviolet to optical region are captured in their rest frame. We use this unique data set, which mitigates complications from source variability, to intercompare the line profiles of C IV λ1549, C III] λ1909, Mg II λ2800, and Hα and evaluate their implications for black hole (BH) mass estimation. We confirm that Mg II and the Balmer lines share similar kinematics and that they deliver mutually consistent BH mass estimates with minimal internal scatter (∼<0.1 dex) using the latest virial mass estimators. Although no virial mass formalism has yet been calibrated for C III], this line does not appear promising for such an application because of the large spread of its velocity width compared to lines of both higher and lower ionization; part of the discrepancy may be due to the difficulty of deblending C III] from its neighboring lines. The situation for C IV is complex and, because of the limited statistics of our small sample, inconclusive. On the one hand, slightly more than half of our sample (4/7) have C IV line widths that correlate reasonably well with Hα line widths, and their respective BH mass estimates agree to within ∼0.15 dex. The rest, on the other hand, exhibit exceptionally broad C IV profiles that overestimate virial masses by factors of 2-5 compared to Hα. As C IV is widely used to study BH demographics at high redshifts, we urgently need to revisit our analysis with a larger sample.

Unique lasing mechanism of localized dispersive nanostructures in InAs/InGaAlAs quantum dash broad interband laser

KAUST Repository

Tan, C. L.; Djie, H. S.; Tan, C. K.; Ooi, Boon S.

2010-01-01

The authors report on the nanowires-like and nanodots-like lasing behaviors in addition to multiple-wavelength interband transitions from InAs/InAlGaAs quantum dash (Qdash) lasers in the range of ~1550 nm. The presence of lasing actions

A REVISED BROAD-LINE REGION RADIUS AND BLACK HOLE MASS FOR THE NARROW-LINE SEYFERT 1 NGC 4051

International Nuclear Information System (INIS)

Denney, K. D.; Watson, L. C.; Peterson, B. M.

2009-01-01

We present the first results from a high sampling rate, multimonth reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from telescopes around the world. The primary goal of this campaign was to obtain either new or improved Hβ reverberation lag measurements for several relatively low luminosity active galactic nuclei (AGNs). We feature results for NGC 4051 here because, until now, this object has been a significant outlier from AGN scaling relationships, e.g., it was previously a ∼2-3σ outlier on the relationship between the broad-line region (BLR) radius and the optical continuum luminosity-the R BLR -L relationship. Our new measurements of the lag time between variations in the continuum and Hβ emission line made from spectroscopic monitoring of NGC 4051 lead to a measured BLR radius of R BLR = 1.87 +0.54 -0.50 light days and black hole mass of M BH = (1.73 +0.55 -0.52 ) x 10 6 M sun . This radius is consistent with that expected from the R BLR -L relationship, based on the present luminosity of NGC 4051 and the most current calibration of the relation by Bentz et al.. We also present a preliminary look at velocity-resolved Hβ light curves and time delay measurements, although we are unable to reconstruct an unambiguous velocity-resolved reverberation signal.

Weight, blood pressure, and dietary benefits after 12 months of a Web-based Nutrition Education Program (DASH for health): longitudinal observational study.

Science.gov (United States)

Moore, Thomas J; Alsabeeh, Nour; Apovian, Caroline M; Murphy, Megan C; Coffman, Gerald A; Cullum-Dugan, Diana; Jenkins, Mark; Cabral, Howard

2008-12-12

The dietary habits of Americans are creating serious health concerns, including obesity, hypertension, diabetes, cardiovascular disease, and even some types of cancer. While considerable attention has been focused on calorie reduction and weight loss, approaches are needed that will not only help the population reduce calorie intake but also consume the type of healthy, well-balanced diet that would prevent this array of medical complications. To design an Internet-based nutrition education program and to explore its effect on weight, blood pressure, and eating habits after 12 months of participation. We designed the DASH for Health program to provide weekly articles about healthy nutrition via the Internet. Dietary advice was based on the DASH diet (Dietary Approaches to Stop Hypertension). The program was offered as a free benefit to the employees of EMC Corporation, and 2834 employees and spouses enrolled. Enrollees voluntarily entered information about themselves on the website (food intake), and we used these self-entered data to determine if the program had any effect. Analyses were based upon the change in weight, blood pressure, and food intake between the baseline period (before the DASH program began) and the 12th month. To be included in an outcome, a subject had to have provided both a baseline and 12th-month entry. After 12 months, 735 of 2834 original enrollees (26%) were still actively using the program. For subjects who were overweight/obese (body mass index > 25; n = 151), weight change at 12 months was -4.2 lbs (95% CI: -2.2, -6.2; P Internet, with no person-to-person contact with health professionals, is associated with significant weight loss, blood pressure lowering, and dietary improvements after 12 months. Effective programs like DASH for Health, delivered via the Internet, can provide benefit to large numbers of subjects at low cost and may help address the nutritional public health crisis.

Effect of carrier relaxation lifetime on the performance of InAs/InP quantum-dash lasers

KAUST Repository

Khan, Mohammed Zahed Mustafa

2011-12-01

The effect of carrier relaxation process into the quantum dash (Qdash) ground state (GS) is examined theoretically by carrier-photon rate equation model incorporating the inhomogeneous broadening. Increase in the relaxation time and the inhomogeneous broadening degrades the threshold current density. Moreover, our results show that a relaxation time of less than 2 ps gives optimum laser performance. © 2011 IEEE.

High performance superluminescent diode with InAs quantum-dashes and chirped AlGaInAs barriers active region

KAUST Repository

Khan, Mohammed Zahed Mustafa; Majid, Mohammed Abdul; Ng, Tien Khee; Ooi, Boon S.

2013-01-01

The demonstration of high power, ultra-low ripple superluminescent diode using multiple quantum-dash-in-a-well layers with variable barrier thickness is reported. The device exhibits >20 mW power, < 0.3dB ripple, and > 80 nm 3dB bandwidth at ~1.55 μm.

GeoDash: Assisting Visual Image Interpretation in Collect Earth Online by Leveraging Big Data on Google Earth Engine

Science.gov (United States)

Markert, K. N.; Ashmall, W.; Johnson, G.; Saah, D. S.; Anderson, E.; Flores Cordova, A. I.; Díaz, A. S. P.; Mollicone, D.; Griffin, R.

2017-12-01

Collect Earth Online (CEO) is a free and open online implementation of the FAO Collect Earth system for collaboratively collecting environmental data through the visual interpretation of Earth observation imagery. The primary collection mechanism in CEO is human interpretation of land surface characteristics in imagery served via Web Map Services (WMS). However, interpreters may not have enough contextual information to classify samples by only viewing the imagery served via WMS, be they high resolution or otherwise. To assist in the interpretation and collection processes in CEO, SERVIR, a joint NASA-USAID initiative that brings Earth observations to improve environmental decision making in developing countries, developed the GeoDash system, an embedded and critical component of CEO. GeoDash leverages Google Earth Engine (GEE) by allowing users to set up custom browser-based widgets that pull from GEE's massive public data catalog. These widgets can be quick looks of other satellite imagery, time series graphs of environmental variables, and statistics panels of the same. Users can customize widgets with any of GEE's image collections, such as the historical Landsat collection with data available since the 1970s, select date ranges, image stretch parameters, graph characteristics, and create custom layouts, all on-the-fly to support plot interpretation in CEO. This presentation focuses on the implementation and potential applications, including the back-end links to GEE and the user interface with custom widget building. GeoDash takes large data volumes and condenses them into meaningful, relevant information for interpreters. While designed initially with national and global forest resource assessments in mind, the system will complement disaster assessments, agriculture management, project monitoring and evaluation, and more.

GeoDash: Assisting Visual Image Interpretation in Collect Earth Online by Leveraging Big Data on Google Earth Engine

Science.gov (United States)

Markert, Kel; Ashmall, William; Johnson, Gary; Saah, David; Mollicone, Danilo; Diaz, Alfonso Sanchez-Paus; Anderson, Eric; Flores, Africa; Griffin, Robert

2017-01-01

Collect Earth Online (CEO) is a free and open online implementation of the FAO Collect Earth system for collaboratively collecting environmental data through the visual interpretation of Earth observation imagery. The primary collection mechanism in CEO is human interpretation of land surface characteristics in imagery served via Web Map Services (WMS). However, interpreters may not have enough contextual information to classify samples by only viewing the imagery served via WMS, be they high resolution or otherwise. To assist in the interpretation and collection processes in CEO, SERVIR, a joint NASA-USAID initiative that brings Earth observations to improve environmental decision making in developing countries, developed the GeoDash system, an embedded and critical component of CEO. GeoDash leverages Google Earth Engine (GEE) by allowing users to set up custom browser-based widgets that pull from GEE's massive public data catalog. These widgets can be quick looks of other satellite imagery, time series graphs of environmental variables, and statistics panels of the same. Users can customize widgets with any of GEE's image collections, such as the historical Landsat collection with data available since the 1970s, select date ranges, image stretch parameters, graph characteristics, and create custom layouts, all on-the-fly to support plot interpretation in CEO. This presentation focuses on the implementation and potential applications, including the back-end links to GEE and the user interface with custom widget building. GeoDash takes large data volumes and condenses them into meaningful, relevant information for interpreters. While designed initially with national and global forest resource assessments in mind, the system will complement disaster assessments, agriculture management, project monitoring and evaluation, and more.

On Line-Elements and Radii: A Correction

Directory of Open Access Journals (Sweden)

Crothers S. J.

2007-04-01

Full Text Available Using a manifold with boundary various line-elements have been proposed as solutions to Einstein’s gravitational field. It is from such line-elements that black holes, expansion of the Universe, and big bang cosmology have been alleged. However, it has been proved that black holes, expansion of the Universe, and big bang cosmology are not consistent with General Relativity. In a previous paper disproving the black hole theory, the writer made an error which, although minor and having no effect on the conclusion that black holes are inconsistent with General Relativity, is corrected herein for the record.

Effects of dietary sodium on metabolites: the Dietary Approaches to Stop Hypertension (DASH)-Sodium Feeding Study.

Science.gov (United States)

Derkach, Andriy; Sampson, Joshua; Joseph, Justin; Playdon, Mary C; Stolzenberg-Solomon, Rachael Z

2017-10-01

Background: High sodium intake is known to increase blood pressure and is difficult to measure in epidemiologic studies. Objective: We examined the effect of sodium intake on metabolites within the DASH (Dietary Approaches to Stop Hypertension Trial)-Sodium Trial to further our understanding of the biological effects of sodium intake beyond blood pressure. Design: The DASH-Sodium Trial randomly assigned individuals to either the DASH diet (low in fat and high in protein, low-fat dairy, and fruits and vegetables) or a control diet for 12 wk. Participants within each diet arm received, in random order, diets containing high (150 nmol or 3450 mg), medium (100 nmol or 2300 mg), and low (50 nmol or 1150 mg) amounts of sodium for 30 d (crossover design). Fasting blood samples were collected at the end of each sodium intervention. We measured 531 identified plasma metabolites in 73 participants at the end of their high- and low-sodium interventions and in 46 participants at the end of their high- and medium-sodium interventions ( N = 119). We used linear mixed-effects regression to model the relation between each log-transformed metabolite and sodium intake. We also combined the resulting P values with Fisher's method to estimate the association between sodium intake and 38 metabolic pathways or groups. Results: Six pathways were associated with sodium intake at a Bonferroni-corrected threshold of 0.0013 (e.g., fatty acid, food component or plant, benzoate, γ-glutamyl amino acid, methionine, and tryptophan). Although 82 metabolites were associated with sodium intake at a false discovery rate ≤0.10, only 4-ethylphenylsufate, a xenobiotic related to benzoate metabolism, was significant at a Bonferroni-corrected threshold ( P Sodium intake is associated with changes in circulating metabolites, including gut microbial, tryptophan, plant component, and γ-glutamyl amino acid-related metabolites. This trial was registered at clinicaltrials.gov as NCT00000608. © 2017

Radiative effect of black carbon aerosol on a squall line case in North China

Science.gov (United States)

Fu, Shizuo; Deng, Xin; Li, Zhe; Xue, Huiwen

2017-11-01

The radiative effect of black carbon aerosol (BC) on a squall line case in north China is studied with the Weather Research and Forecasting model. Before the initiation of the squall line, the surface-emitted BC is mixed only in the boundary layer (BL). BC is then transported from the BL into the free troposphere by the updrafts in the squall line system. Once distributed in the atmosphere, BC absorbs solar radiation and heats the surrounding air. The maximum increase of temperature is 0.05 K for the moderately polluted case bc2 and 0.37 K for the heavily polluted case bc20. In case bc2, where the BC concentration is not very high, the solar flux reaching the surface, the sensible heat flux, and the latent heat flux are not significantly affected by BC. In case bc20, the solar flux reaching the surface, the sensible heat flux, and the latent heat flux are reduced by up to 80, 30, and 21 W m- 2, respectively. The reduced surface evaporation leads to a reduced vapor amount at the early stage. After some time, the heating effect causes a large-scale convergence and brings slightly more vapor into the domain. The effect of BC on the cold pool strength and low-level wind shear is small and hence does not significantly affect the triggering of new convections. In addition, our results show that the effect of BC is negligible on the strength and rain rate of the squall line case.

Toxicity assessment of carbon black waste: A by-product from oil refineries

Energy Technology Data Exchange (ETDEWEB)

Zhen, Xu; Ng, Wei Cheng [NUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, 138602 (Singapore); Fendy; Tong, Yen Wah [Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 (Singapore); Dai, Yanjun [School of Mechanical Engineering, Shanghai Jiaotong University, Shanghai, 200240 (China); Neoh, Koon Gee, E-mail: chenkg@nus.edu.sg [Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 (Singapore); Wang, Chi-Hwa, E-mail: chewch@nus.edu.sg [Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 (Singapore)

2017-01-05

Highlights: • Carbon black waste extract decreased cell viability in a dose and time-dependent manner. • Apoptosis of human cell lines was induced by carbon black waste extract. • Carbon black waste extract elicited oxidative stress by increasing intracellular ROS generation. • Carbon black waste extract impaired antioxidant enzymatic activities of human cell lines. • The high toxicity of carbon black waste extract could be attributed mainly to the effect of vanadium. - Abstract: In Singapore, approximately 30 t/day of carbon-based solid waste are produced from petrochemical processes. This carbon black waste has been shown to possess physical properties that are characteristic of a good adsorbent such as high external surface area. Therefore, there is a growing interest to reutilize and process this carbon black waste into secondary materials such as adsorbents. However, the carbon black waste obtained from petrochemical industries may contain heavy metals that are hazardous to human health and the environment, hence restricting its full potential for re-utilization. Therefore, it is important to examine the possible toxicity effects and toxicity mechanism of carbon black waste on human health. In this study, inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis showed that the heavy metals, vanadium (V), molybdenum (Mo) and nickel (Ni), were present in the carbon black waste in high concentrations. Three human cell lines (HepG2 cells, MRC-5 cells and MDA-MB-231 cells) were used to investigate the toxicity of carbon black waste extract in a variety of in vitro assays. Results from MTS assays indicated that carbon black waste extract decreased the viability of all three cell lines in a dose and time-dependent manner. Observations from confocal microscopy further confirmed this phenomenon. Flow cytometry assay also showed that carbon black waste extract induced apoptosis of human cell lines, and the level of apoptosis increased with

Toxicity assessment of carbon black waste: A by-product from oil refineries

International Nuclear Information System (INIS)

Zhen, Xu; Ng, Wei Cheng; Fendy; Tong, Yen Wah; Dai, Yanjun; Neoh, Koon Gee; Wang, Chi-Hwa

2017-01-01

Highlights: • Carbon black waste extract decreased cell viability in a dose and time-dependent manner. • Apoptosis of human cell lines was induced by carbon black waste extract. • Carbon black waste extract elicited oxidative stress by increasing intracellular ROS generation. • Carbon black waste extract impaired antioxidant enzymatic activities of human cell lines. • The high toxicity of carbon black waste extract could be attributed mainly to the effect of vanadium. - Abstract: In Singapore, approximately 30 t/day of carbon-based solid waste are produced from petrochemical processes. This carbon black waste has been shown to possess physical properties that are characteristic of a good adsorbent such as high external surface area. Therefore, there is a growing interest to reutilize and process this carbon black waste into secondary materials such as adsorbents. However, the carbon black waste obtained from petrochemical industries may contain heavy metals that are hazardous to human health and the environment, hence restricting its full potential for re-utilization. Therefore, it is important to examine the possible toxicity effects and toxicity mechanism of carbon black waste on human health. In this study, inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis showed that the heavy metals, vanadium (V), molybdenum (Mo) and nickel (Ni), were present in the carbon black waste in high concentrations. Three human cell lines (HepG2 cells, MRC-5 cells and MDA-MB-231 cells) were used to investigate the toxicity of carbon black waste extract in a variety of in vitro assays. Results from MTS assays indicated that carbon black waste extract decreased the viability of all three cell lines in a dose and time-dependent manner. Observations from confocal microscopy further confirmed this phenomenon. Flow cytometry assay also showed that carbon black waste extract induced apoptosis of human cell lines, and the level of apoptosis increased with

Binding of Substrate Locks the Electrochemistry of CRY-DASH into DNA Repair.

Science.gov (United States)

Gindt, Yvonne M; Messyasz, Adriana; Jumbo, Pamela I

2015-05-12

VcCry1, a member of the CRY-DASH family, may serve two diverse roles in vivo, including blue-light signaling and repair of UV-damaged DNA. We have discovered that the electrochemistry of the flavin adenine dinucleotide cofactor of VcCry1 is locked to cycle only between the hydroquinone and neutral semiquinone states when UV-damaged DNA is present. Other potential substrates, including undamaged DNA and ATP, have no discernible effect on the electrochemistry, and the kinetics of the reduction is unaffected by damaged DNA. Binding of the damaged DNA substrate determines the role of the protein and prevents the presumed photochemistry required for blue-light signaling.

Eternal higher spin black holes: a thermofield Interpretation

International Nuclear Information System (INIS)

Castro, Alejandra; Iqbal, Nabil; Llabrés, Eva

2016-01-01

We study Lorentzian eternal black holes in the Chern-Simons sector of AdS 3 higher spin gravity. We probe such black holes using bulk Wilson lines and motivate new regularity conditions that must be obeyed by the bulk connections in order for the geometry to be consistent with an interpretation as a thermofield state in the dual CFT 2 . We demonstrate that any higher spin black hole may be placed in a gauge that satisfies these conditions: this is the Chern-Simons analogue of the construction of Kruskal coordinates that permit passage through the black hole horizon. We also argue that the Wilson line provides a higher-spin notion of causality in higher spin gravity that can be used to associate a Penrose diagram with the black hole. We present some applications of the formalism, including a study of the time-dependent entanglement entropy arising from the higher spin black hole interior and evidence for an emergent AdS 2 region in the extremal limit.

Measuring the spins of accreting black holes

International Nuclear Information System (INIS)

McClintock, Jeffrey E; Narayan, Ramesh; Gou, Lijun; Kulkarni, Akshay; Penna, Robert F; Steiner, James F; Davis, Shane W; Orosz, Jerome A; Remillard, Ronald A

2011-01-01

A typical galaxy is thought to contain tens of millions of stellar-mass black holes, the collapsed remnants of once massive stars, and a single nuclear supermassive black hole. Both classes of black holes accrete gas from their environments. The accreting gas forms a flattened orbiting structure known as an accretion disk. During the past several years, it has become possible to obtain measurements of the spins of the two classes of black holes by modeling the x-ray emission from their accretion disks. Two methods are employed, both of which depend upon identifying the inner radius of the accretion disk with the innermost stable circular orbit, whose radius depends only on the mass and spin of the black hole. In the Fe Kα method, which applies to both classes of black holes, one models the profile of the relativistically broadened iron line with a special focus on the gravitationally redshifted red wing of the line. In the continuum-fitting (CF) method, which has so far only been applied to stellar-mass black holes, one models the thermal x-ray continuum spectrum of the accretion disk. We discuss both methods, with a strong emphasis on the CF method and its application to stellar-mass black holes. Spin results for eight stellar-mass black holes are summarized. These data are used to argue that the high spins of at least some of these black holes are natal, and that the presence or absence of relativistic jets in accreting black holes is not entirely determined by the spin of the black hole.

Electron–Positron Pair Creation Close to a Black Hole Horizon: Redshifted Annihilation Line in the Emergent X-Ray Spectra of a Black Hole. I.

Science.gov (United States)

Laurent, Philippe; Titarchuk, Lev

2018-06-01

We consider a Compton cloud (CC) surrounding a black hole (BH) in an accreting BH system, where electrons propagate with thermal and bulk velocities. In that cloud, soft (disk) photons may be upscattered off these energetic electrons and attain energies of several MeV. They could then create pairs due to photon–photon interactions. In this paper, we study the formation of the 511 keV annihilation line due to this photon–photon interaction, which results in the creation of electron–positron pairs, followed by the annihilation of the created positrons with the CC electrons. The appropriate conditions for annihilation-line generation take place very close to a BH horizon within (103–104)m cm from it, where m is the BH hole mass in solar units. As a result, the created annihilation line should be seen by the Earth observer as a blackbody bump, or the so-called reflection bump at energies around (511/20) (20/z) keV, where z ∼ 20 is a typical gravitational redshift experienced by the created annihilation-line photons when they emerge. This transient feature should occur in any accreting BH system, either galactic or extragalactic. Observational evidences for this feature in several galactic BH systems is detailed in an accompanying paper. An extended hard tail of the spectrum up to 1 MeV may also be formed due to X-ray photons upscattering off created pairs.

Effect of the number of stacking layers on the characteristics of quantum-dash lasers

KAUST Repository

Khan, Mohammed Zahed Mustafa

2011-06-27

A theoretical model is evaluated to investigate the characteristics of InAs/InP quantum dash (Qdash) lasers as a function of the stack number. The model is based on multimode carrier-photon rate equations and accounts for both inhomogeneous and homogeneous broadenings of the optical gain. The numerical results show a non monotonic increase in the threshold current density and a red shift in the lasing wavelength on increasing the stack number, which agrees well with reported experimental results. This observation may partly be attributed to an increase of inhomogeneity in the active region.

Effect of the number of stacking layers on the characteristics of quantum-dash lasers

KAUST Repository

Khan, Mohammed Zahed Mustafa; Bhattacharya, Pallab K.; Ng, Tien Khee; Ooi, Boon S.; Schwingenschlö gl, Udo

2011-01-01

A theoretical model is evaluated to investigate the characteristics of InAs/InP quantum dash (Qdash) lasers as a function of the stack number. The model is based on multimode carrier-photon rate equations and accounts for both inhomogeneous and homogeneous broadenings of the optical gain. The numerical results show a non monotonic increase in the threshold current density and a red shift in the lasing wavelength on increasing the stack number, which agrees well with reported experimental results. This observation may partly be attributed to an increase of inhomogeneity in the active region.

The Denver Aerosol Sources and Health (DASH) study: Overview and early findings

Science.gov (United States)

Vedal, S.; Hannigan, M. P.; Dutton, S. J.; Miller, S. L.; Milford, J. B.; Rabinovitch, N.; Kim, S.-Y.; Sheppard, L.

Improved understanding of the sources of air pollution that are most harmful could aid in developing more effective measures for protecting human health. The Denver Aerosol Sources and Health (DASH) study was designed to identify the sources of ambient fine particulate matter (PM 2.5) that are most responsible for the adverse health effects of short-term exposure to PM 2.5. Daily 24-h PM 2.5 sampling began in July 2002 at a residential monitoring site in Denver, Colorado, using both Teflon and quartz filter samplers. Sampling is planned to continue through 2008. Chemical speciation is being carried out for mass, inorganic ionic compounds (sulfate, nitrate and ammonium), and carbonaceous components, including elemental carbon, organic carbon, temperature-resolved organic carbon fractions and a large array of organic compounds. In addition, water-soluble metals were measured daily for 12 months in 2003. A receptor-based source apportionment approach utilizing positive matrix factorization (PMF) will be used to identify PM 2.5 source contributions for each 24-h period. Based on a preliminary assessment using synthetic data, the proposed source apportionment should be able to identify many important sources on a daily basis, including secondary ammonium nitrate and ammonium sulfate, diesel vehicle exhaust, road dust, wood combustion and vegetative debris. Meat cooking, gasoline vehicle exhaust and natural gas combustion were more challenging for PMF to accurately identify due to high detection limits for certain organic molecular marker compounds. Measurements of these compounds are being improved and supplemented with additional organic molecular marker compounds. The health study will investigate associations between daily source contributions and an array of health endpoints, including daily mortality and hospitalizations and measures of asthma control in asthmatic children. Findings from the DASH study, in addition to being of interest to policymakers, by

Assessing physical function in adult acquired major upper-limb amputees by combining the Disabilities of the Arm, Shoulder and Hand (DASH) Outcome Questionnaire and clinical examination.

Science.gov (United States)

Ostlie, Kristin; Franklin, Rosemary J; Skjeldal, Ola H; Skrondal, Anders; Magnus, Per

2011-10-01

To describe physical function in adult acquired major upper-limb amputees (ULAs) by combining self-assessed arm function and physical measures obtained by clinical examinations; to estimate associations between background factors and self-assessed arm function in ULAs; and to assess whether clinical examination findings may be used to detect reduced arm function in unilateral ULAs. postal questionnaires and clinical examinations. Norwegian ULA population. Clinical examinations performed at 3 clinics. Questionnaires: population-based sample (n=224; 57.4% response rate). Clinical examinations: combined referred sample and convenience sample of questionnaire responders (n=70; 83.3% of those invited). SURVEY inclusion criteria: adult acquired major upper-limb amputation, resident in Norway, mastering of spoken and written Norwegian. Not applicable. The Disabilities of the Arm, Shoulder and Hand (DASH) Outcome Questionnaire, and clinical examination of joint motion and muscle strength with and without prostheses. Mean DASH score was 22.7 (95% confidence interval [CI], 20.3-25.0); in bilateral amputees, 35.7 (95% CI, 23.0-48.4); and in unilateral amputees, 22.1 (95% CI, 19.8-24.5). A lower unilateral DASH score (better function) was associated with paid employment (vs not in paid employment: adjusted regression coefficient [aB]=-5.40, P=.033; vs students: aB=-13.88, P=.022), increasing postamputation time (aB=-.27, P=.001), and Norwegian ethnicity (aB=-14.45, P<.001). At clinical examination, we found a high frequency of impaired neck mobility and varying frequencies of impaired joint motion and strength at the shoulder, elbow, and forearm level. Prosthesis wear was associated with impaired joint motion in all upper-limb joints (P<.006) and with reduced shoulder abduction strength (P=.002). Impaired without-prosthesis joint motion in shoulder flexion (ipsilateral: aB=12.19, P=.001) and shoulder abduction (ipsilateral: aB=12.01, P=.005; contralateral: aB=28.82, P=.004

Hairy black holes in cubic quasi-topological gravity

Energy Technology Data Exchange (ETDEWEB)

Dykaar, Hannah [Department of Physics and Astronomy, University of Waterloo,200 University Avenue West, Waterloo, ON, N2L 3G1 (Canada); Department of Physics, McGill University,3600 rue University, Montreal, QC, H3A 2T8 (Canada); Hennigar, Robie A.; Mann, Robert B. [Department of Physics and Astronomy, University of Waterloo,200 University Avenue West, Waterloo, ON, N2L 3G1 (Canada)

2017-05-09

We construct a class of five dimensional black hole solutions to cubic quasi-topological gravity with conformal scalar hair and study their thermodynamics. We find these black holes provide the second example of black hole λ-lines: a line of second order (continuous) phase transitions, akin to the fluid/superfluid transition of {sup 4}He. Examples of isolated critical points are found for spherical black holes, marking the first in the literature to date. We also find various novel and interesting phase structures, including an isolated critical point occurring in conjunction with a double reentrant phase transition. The AdS vacua of the theory are studied, finding ghost-free configurations where the scalar field takes on a non-zero constant value, in notable contrast to the five dimensional Lovelock case.

A pan-inhibitor of DASH family enzymes induces immune-mediated regression of murine sarcoma and is a potent adjuvant to dendritic cell vaccination and adoptive T-cell therapy.

Science.gov (United States)

Duncan, Brynn B; Highfill, Steven L; Qin, Haiying; Bouchkouj, Najat; Larabee, Shannon; Zhao, Peng; Woznica, Iwona; Liu, Yuxin; Li, Youhua; Wu, Wengen; Lai, Jack H; Jones, Barry; Mackall, Crystal L; Bachovchin, William W; Fry, Terry J

2013-10-01

Multimodality therapy consisting of surgery, chemotherapy, and radiation will fail in approximately 40% of patients with pediatric sarcomas and result in substantial long-term morbidity in those who are cured. Immunotherapeutic regimens for the treatment of solid tumors typically generate antigen-specific responses too weak to overcome considerable tumor burden and tumor suppressive mechanisms and are in need of adjuvant assistance. Previous work suggests that inhibitors of DASH (dipeptidyl peptidase IV activity and/or structural homologs) enzymes can mediate tumor regression by immune-mediated mechanisms. Herein, we demonstrate that the DASH inhibitor, ARI-4175, can induce regression and eradication of well-established solid tumors, both as a single agent and as an adjuvant to a dendritic cell (DC) vaccine and adoptive cell therapy (ACT) in mice implanted with the M3-9-M rhabdomyosarcoma cell line. Treatment with effective doses of ARI-4175 correlated with recruitment of myeloid (CD11b) cells, particularly myeloid DCs, to secondary lymphoid tissues and with reduced frequency of intratumoral monocytic (CD11bLy6-CLy6-G) myeloid-derived suppressor cells. In immunocompetent mice, combining ARI-4175 with a DC vaccine or ACT with tumor-primed T cells produced significant improvements in tumor responses against well-established M3-9-M tumors. In M3-9-M-bearing immunodeficient (Rag1) mice, ACT combined with ARI-4175 produced greater tumor responses and significantly improved survival compared with either treatment alone. These studies warrant the clinical investigation of ARI-4175 for treatment of sarcomas and other malignancies, particularly as an adjuvant to tumor vaccines and ACT.

The Hunt for Low-Mass Black Holes in the JWST Era

Science.gov (United States)

Cann, Jenna; Satyapal, Shobita; Abel, Nicholas; Ricci, Claudio; Gliozzi, Mario; Blecha, Laura; Secrest, Nathan

2018-01-01

Most, if not all, massive galaxies have a central supermassive black hole (SMBH) millions to billions of times the mass of the Sun. While the properties of SMBHs and their host galaxies have been well-studied in massive galaxies, very few SMBHs have been found in galaxies with low masses and those with small bulges. This is a significant deficiency, because the study of this population allows us to gain an understanding of merger-free pathways to black hole growth, and to gain insight into the origin and growth of SMBH ‘seeds’, thought to have formed at high redshift. Most studies aimed at finding SMBHs have been conducted using optical spectroscopic studies, where active SMBHs (active galactic nuclei or AGNs) display distinctive optical emission lines indicative of accreting SMBHs. However, in low mass (dwarf) galaxies, the SMBHs will likely be less massive, and can be energetically weak and possibly deeply embedded in their host galaxies. As a result, the optical emission lines may be dominated by star formation regions, severely limiting the diagnostic power of optical surveys in finding and characterizing the properties of the AGN in dwarf galaxies. In such galaxies, infrared coronal lines provide a robust method of finding AGNs. Furthermore, as the black hole mass decreases, the Schwarzschild radius of the black hole decreases, and in response, the temperature of the surrounding accretion disk increases. The shape of the ionizing radiation spectral energy distribution therefore changes with black hole mass, which will affect the emission line spectrum from the surrounding gas. In this work, we investigate the diagnostic power of infrared coronal lines and the effect of black hole mass on the emission line spectra from AGNs, with a particular focus on the emission lines accessible by JWST.

Dietary approach to stop hypertension (DASH) diet and risk of renal function decline and all-cause mortality in renal transplant recipients

NARCIS (Netherlands)

Osté, M.C.J.; Gomes-neto, A.W.; Corpeleijn, E.; Gans, R.O.B.; De Borst, M.H.; Van Den Berg, E.; Soedamah-Muthu, S.S.; Kromhout, D.; Navis, G.J.; Bakker, S.J.L.

Renal transplant recipients (RTR) are at risk of decline of graft function and premature mortality, with high blood pressure as important risk factor for both. To study the association of the Dietary Approach to Stop Hypertension (DASH) diet with these adverse events, we conducted a prospective

Chirped InAs/InP quantum-dash laser with enhanced broad spectrum of stimulated emission

KAUST Repository

Khan, Mohammed Zahed Mustafa

2013-03-01

We report on the demonstration of 50 nm (full-width at half-maximum) broadband stimulated emission from a chirped AlGaInAs barrier thickness multi-stack InAs/InP quantum dash (Qdash) laser. The 2 ?m wide uncoated Fabry-Perot (FP) ridge-waveguide laser exhibits a total power of 0.18 W, corresponding to an average spectral power density of 3.5 mW/nm, under pulsed current conditions. Intentional extended inhomogeneity across the Qdash stacks have been attributed to the enhancement of broadband emission. © 2013 American Institute of Physics.

Chirped InAs/InP quantum-dash laser with enhanced broad spectrum of stimulated emission

KAUST Repository

Khan, Mohammed Zahed Mustafa; Bhattacharya, Pallab K.; Lee, Chi-Sen; Ng, Tien Khee; Ooi, Boon S.

2013-01-01

We report on the demonstration of 50 nm (full-width at half-maximum) broadband stimulated emission from a chirped AlGaInAs barrier thickness multi-stack InAs/InP quantum dash (Qdash) laser. The 2 ?m wide uncoated Fabry-Perot (FP) ridge-waveguide laser exhibits a total power of 0.18 W, corresponding to an average spectral power density of 3.5 mW/nm, under pulsed current conditions. Intentional extended inhomogeneity across the Qdash stacks have been attributed to the enhancement of broadband emission. © 2013 American Institute of Physics.

Gain and refractive index dynamics in p-doped InAs quantum dash semiconductor optical amplifiers

International Nuclear Information System (INIS)

Komolibus, Katarzyna; Piwonski, Tomasz; Joshi, Siddharth; Chimot, Nicolas; Lelarge, Francois; Houlihan, John; Huyet, Guillaume

2016-01-01

The ultrafast carrier dynamics in a p-doped dash-in-a-well structure at 1.5 μm is experimentally investigated. An analysis of the timescales related to carrier relaxation and escape processes as well as the “dynamical” linewidth enhancement factor is presented and compared with results obtained from similar un-doped materials. Intentional p-doping of the active region results in an enhancement of the intermediate timescale of the gain dynamics associated with phonon-assisted electron capture and a reduction of the α-factor due to increased differential gain.

Gain and refractive index dynamics in p-doped InAs quantum dash semiconductor optical amplifiers

Energy Technology Data Exchange (ETDEWEB)

Komolibus, Katarzyna [Centre for Advanced Photonics and Process Analysis, Cork Institute of Technology, Cork T12 P928 (Ireland); Tyndall National Institute, University College Cork, Cork T12 R5CP (Ireland); Piwonski, Tomasz, E-mail: tomasz.piwonski@tyndall.ie [Tyndall National Institute, University College Cork, Cork T12 R5CP (Ireland); Joshi, Siddharth; Chimot, Nicolas; Lelarge, Francois [III-V Lab, Alcatel Lucent Bell Labs, Palaiseau F-91767 (France); Houlihan, John [Waterford Institute of Technology, Waterford X91 K0EK (Ireland); Huyet, Guillaume [Centre for Advanced Photonics and Process Analysis, Cork Institute of Technology, Cork T12 P928 (Ireland); Tyndall National Institute, University College Cork, Cork T12 R5CP (Ireland); National Research University of Information Technologies, Mechanics and Optics, Saint Petersburg 197101 (Russian Federation)

2016-07-18

The ultrafast carrier dynamics in a p-doped dash-in-a-well structure at 1.5 μm is experimentally investigated. An analysis of the timescales related to carrier relaxation and escape processes as well as the “dynamical” linewidth enhancement factor is presented and compared with results obtained from similar un-doped materials. Intentional p-doping of the active region results in an enhancement of the intermediate timescale of the gain dynamics associated with phonon-assisted electron capture and a reduction of the α-factor due to increased differential gain.

Thermodynamics of hairy black holes in Lovelock gravity

Science.gov (United States)

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

2017-02-01

We perform a thorough study of the thermodynamic properties of a class of Lovelock black holes with conformal scalar hair arising from coupling of a real scalar field to the dimensionally extended Euler densities. We study the linearized equations of motion of the theory and describe constraints under which the theory is free from ghosts/tachyons. We then consider, within the context of black hole chemistry, the thermodynamics of the hairy black holes in the Gauss-Bonnet and cubic Lovelock theories. We clarify the connection between isolated critical points and thermodynamic singularities, finding a one parameter family of these critical points which occur for well-defined thermodynamic parameters. We also report on a number of novel results, including `virtual triple points' and the first example of a `λ-line' — a line of second order phase transitions — in black hole thermodynamics.

High-Performance 1.55-µm Superluminescent Diode Based on Broad Gain InAs/InGaAlAs/InP Quantum Dash Active Region

KAUST Repository

Khan, Mohammed Zahed Mustafa

2014-08-01

We report on the high-performance characteristics from superluminescent diodes (SLDs) based on four-stack InAs/InGaAlAs chirped-barrier thickness quantum dash (Qdash) in a well structure. The active region exhibits a measured broad gain spectrum of 140 nm, with a peak modal gain of ~41 cm-1. The noncoated two-section gainabsorber broad-area and ridge-waveguide device configuration exhibits an output power of > 20 mW and > 12 mW, respectively. The corresponding -3-dB bandwidths span ~82 nm and ~72 nm, with a small spectral ripple of <; 0.2 dB, related largely to the contribution from dispersive height dash ensembles of the highly inhomogeneous active region. These C-L communication band devices will find applications in various cross-disciplinary fields of optical metrology, optical coherent tomography, etc.

Effect of optical waveguiding mechanism on the lasing action of chirped InAs/AlGaInAs/InP quantum dash lasers

KAUST Repository

Khan, Mohammed Zahed Mustafa; Ng, Tien Khee; Lee, C.-S.; Bhattacharya, P.; Ooi, Boon S.

2013-01-01

We report on the atypical emission dynamics of InAs/AlGaInAs/InP quantum dash (Qdash) lasers employing varying AlGaInAs barrier thickness (multilayer-chirped structure). The analysis is carried out via fabry-perot (FP) ridge (RW) and stripe

Black Hole Dynamic Potentials Koustubh Ajit Kabe

Indian Academy of Sciences (India)

Abstract. In the following paper, certain black hole dynamic potentials have been developed definitively on the lines of classical thermodynam- ics. 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.

Utilisation of an eta(3)-allyl hydride complex, formed by UV irradiation, as a controlled source of 16-electron (eta(5)-C(5)Me(5))Rh(CH(2)[double bond, length as m-dash]CHMe).

Science.gov (United States)

Sexton, Catherine J; López-Serrano, Joaquín; Lledós, Agustí; Duckett, Simon B

2008-10-21

Low temperature UV irradiation of solutions of (eta(5)-C(5)Me(5))Rh(CH(2)[double bond, length as m-dash]CHMe)(2) yields (eta(5)-C(5)Me(5))Rh(eta(3)-CH(2)CHCH(2))(H), which provides controlled access to the 16-electron fragment (eta(5)-C(5)Me(5))Rh(CH(2)[double bond, length as m-dash]CHMe).

Effect of active medium inhomogeneity on lasing characteristics of InAs/InP quantum-dash lasers

KAUST Repository

Khan, Mohammed Zahed Mustafa

2010-01-01

The authors report on the effect of quantum-dash (Qdash) inhomogeneity on the characteristics of InAs/InP Qdash laser utilizing a single state rate equation model. The inhomogeneity is assumed to follow the Gaussian approximation. From our observation, an increased in Qdash inhomogeneity results in increasing of threshold current density and redshifting of the peak lasing wavelength. The lasing linewidth of the Qdash lasers has also found to increase under large injection current, attaining a full width at half maximum (FWHM) of ~ 17 nm.

How A Black Hole Lights Up Its Surroundings

Science.gov (United States)

Kohler, Susanna

2017-10-01

How do the supermassive black holes that live at the centers of galaxies influence their environments? New observations of a distant active galaxy offer clues about this interaction.Signs of CoevolutionPlot demonstrating the m-sigma relation, the empirical correlation between the stellar velocity dispersion of a galactic bulge and the mass of the supermassive black hole at its center. [Msigma]We know that the centers of active galaxies host supermassive black holes with masses of millions to billions of suns. One mystery surrounding these beasts is that they are observed to evolve simultaneously with their host galaxies for instance, an empirical relationship is seen between the growth of a black hole and the growth of its host galaxys bulge. This suggests that there must be a feedback mechanism through which the evolution of a black hole is linked to that of its host galaxy.One proposed source of this coupling is the powerful jets emitted from the poles of these supermassive black holes. These jets are thought to be produced as some of the material accreting onto the black hole is flung out, confined by surrounding gas and magnetic fields. Because the jets of hot gas and radiation extend outward through the host galaxy, they provide a means for the black hole to influence the gas and dust of its surroundings.In our current model of a radio-loud active galactic nuclei,a region of hot, ionized gas the narrow-line region lies beyond the sphere of influence of the supermassive black hole. [C.M. Urry and P. Padovani]Clues in the Narrow-Line RegionThe region of gas thought to sit just outside of the black holes sphere of influence (at a distance of perhaps a thousand to a few thousand light-years) is known as the narrow line region so named because we observe narrow emission lines from this gas. Given its hot, ionized state, this gas must somehow be being pummeled with energy. In the canonical picture, radiation from the black hole heats the gas directly in a process

Blacks in Pop Music: A Short Story.

Science.gov (United States)

Rickelman, Melinda

1991-01-01

A short history of black pop music includes artists who have changed pop music or culture and highlights from the 1920s into the 1980s, from Fats Waller to Michael Jackson. In black pop music, there is a direct line of influence from the sharecropper to the current Top 40. (SLD)

Dietary habits, poverty, and chronic kidney disease in an urban population.

Science.gov (United States)

Crews, Deidra C; Kuczmarski, Marie Fanelli; Miller, Edgar R; Zonderman, Alan B; Evans, Michele K; Powe, Neil R

2015-03-01

Poverty is associated with chronic kidney disease (CKD) in the United States and worldwide. Poor dietary habits may contribute to this disparity. Cross-sectional study. A total of 2,058 community-dwelling adults aged 30 to 64 years residing in Baltimore City, Maryland. Adherence to the Dietary Approaches to Stop Hypertension (DASH) diet. DASH scoring based on 9 target nutrients (total fat, saturated fat, protein, fiber, cholesterol, calcium, magnesium, sodium, and potassium); adherence defined as score ≥4.5 of maximum possible score of 9. Poverty (self-reported household income poverty status. Among 2,058 participants (mean age 48 years; 57% black; 44% male; 42% with poverty), median DASH score was low, 1.5 (interquartile range, 1-2.5). Only 5.4% were adherent. Poverty, male sex, black race, and smoking were more prevalent among the lower DASH score tertiles, whereas higher education and regular health care were more prevalent among the highest DASH score tertile (P poverty compared with nonpoverty group (P poverty and 3.8% of the nonpoverty group had CKD (P = .05). The lowest DASH tertile (compared with the highest) was associated with more CKD among the poverty (AOR 3.15, 95% confidence interval 1.51-6.56), but not among the nonpoverty group (AOR 0.73, 95% confidence interval 0.37-1.43; P interaction = .001). Poor dietary habits are strongly associated with CKD among the urban poor and may represent a target for interventions aimed at reducing disparities in CKD. Copyright © 2015 National Kidney Foundation, Inc. All rights reserved.

Calibration and Limitations of the Mg II Line-based Black Hole Masses

Science.gov (United States)

Woo, Jong-Hak; Le, Huynh Anh N.; Karouzos, Marios; Park, Dawoo; Park, Daeseong; Malkan, Matthew A.; Treu, Tommaso; Bennert, Vardha N.

2018-06-01

We present single-epoch black hole mass ({M}BH}) calibrations based on the rest-frame ultraviolet (UV) and optical measurements of Mg II 2798 Å and Hβ 4861 Å lines and the active galactic nucleus (AGN) continuum, using a sample of 52 moderate-luminosity AGNs at z ∼ 0.4 and z ∼ 0.6 with high-quality Keck spectra. We combine this sample with a large number of luminous AGNs from the Sloan Digital Sky Survey to increase the dynamic range for a better comparison of UV and optical velocity and luminosity measurements. With respect to the reference {M}BH} based on the line dispersion of Hβ and continuum luminosity at 5100 Å, we calibrate the UV and optical mass estimators by determining the best-fit values of the coefficients in the mass equation. By investigating whether the UV estimators show a systematic trend with Eddington ratio, FWHM of Hβ, Fe II strength, or UV/optical slope, we find no significant bias except for the slope. By fitting the systematic difference of Mg II-based and Hβ-based masses with the L 3000/L 5100 ratio, we provide a correction term as a function of the spectral index as ΔC = 0.24 (1 + α λ ) + 0.17, which can be added to the Mg II-based mass estimators if the spectral slope can be well determined. The derived UV mass estimators typically show >∼0.2 dex intrinsic scatter with respect to the Hβ-based {M}BH}, suggesting that the UV-based mass has an additional uncertainty of ∼0.2 dex, even if high-quality rest-frame UV spectra are available.

Adherence to the USDA Food Guide, DASH Eating Plan, and Mediterranean dietary pattern reduces risk of colorectal adenoma.

Science.gov (United States)

Dixon, L Beth; Subar, Amy F; Peters, Ulrike; Weissfeld, Joel L; Bresalier, Robert S; Risch, Adam; Schatzkin, Arthur; Hayes, Richard B

2007-11-01

The 2005 Dietary Guidelines for Americans include quantitative recommendations for 2 eating patterns, the USDA Food Guide and the Dietary Approaches to Stop Hypertension (DASH) Eating Plan, to promote optimal health and reduce disease risk. A Mediterranean dietary pattern has also been promoted for health benefits. Our objective was to determine whether adherence to the USDA Food Guide recommendations, the DASH Eating Plan, or a Mediterranean dietary pattern is associated with reduced risk of distal colorectal adenoma. In the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, men and women aged 55-74 y were screened for colorectal cancer by sigmoidoscopy at 10 centers in the U.S. After adjusting for potential confounders, men who most complied with the USDA Food Guide recommendations had a 26% reduced risk of colorectal adenoma compared with men who least complied with the recommendations (OR USDA score >or= 5 vs. dietary pattern. Women who most complied with the USDA Food Guide recommendations had an 18% reduced risk for colorectal adenoma, but subgroup analyses revealed protective associations only for current smokers (OR USDA score >or= 5 vs. or= 5 vs. dietary recommendations or a Mediterranean dietary pattern is associated with reduced risk of colorectal adenoma, especially in men.

Implementación de un sistema de streaming de contenidos multimedia con tecnología MPEG-DASH basado en la plataforma Gstreamer

NARCIS (Netherlands)

D. Gómez (David)

2015-01-01

htmlabstractIn this Master Thesis, an end-to-end media framework for the delivery of MPEG-DASH content has been developed. This framework includes and allows the configuration of all the required steps along the end-to-end media delivery chain, from the generation, encoding, segmentation and storage

Disorder dependent half-metallicity in Mn2CoSi inverse Heusler alloy

International Nuclear Information System (INIS)

Singh, Mukhtiyar; Saini, Hardev S.; Thakur, Jyoti; Reshak, Ali H.; Kashyap, Manish K.

2013-01-01

Heusler alloys based thin-films often exhibit a degree of atomic disorder which leads to the lowering of spin polarization in spintronic devices. We present ab-initio calculations of atomic disorder effects on spin polarization and half-metallicity of Mn 2 CoSi inverse Heusler alloy. The five types of disorder in Mn 2 CoSi have been proposed and investigated in detail. The A2 a -type and B2-type disorders destroy the half-metallicity whereas it sustains for all disorders concentrations in DO 3a - and A2 b -type disorder and for smallest disorder concentration studied in DO 3b -type disorder. Lower formation energy/atom for A2 b -type disorder than other four disorders in Mn 2 CoSi advocates the stability of this disorder. The total magnetic moment shows a strong dependence on the disorder and the change in chemical environment. The 100% spin polarization even in the presence of disorders explicitly supports that these disorders shall not hinder the use of Mn 2 CoSi inverse Heusler alloy in device applications. - Graphical abstract: Minority-spin gap (E g↓ ) and HM gap (E sf ) as a function of concentrations of various possible disorder in Mn 2 CoSi inverse Heusler alloy. The squares with solid line (black color)/dotted line (blue color)/dashed line (red color) reperesents E g↓ for DO 3a -/DO 3b -/A2 b -type disorder in Mn 2 CoSi and the spheres with solid line (black color)/dottedline (blue color)/dashed line (red color) represents E sf for DO 3a -/DO 3b -/A2 b -type disorder in Mn 2 CoSi. - Highlights: • The DO 3 - and A2-type disorders do not affect the half-metallicity in Mn 2 CoSi. • The B2-type disorder solely destroys half-metallicity in Mn 2 CoSi. • The A2-type disorder most probable to occur out of all three types. • The total spin magnetic moment strongly depends on the disorder concentrations

Harmonic oscillator in Snyder space: The classical case and the ...

Indian Academy of Sciences (India)

ω = 8.5 · 10−4 (continuous line), and for normal q(t) (dashed line). Figure 2. Plot for the two branches of Snyder p(t) with l = 10−5 and ω = 8.5 · 10−4 (continuous line), and for normal p(t) (dashed line). where d is a suitable constant in order to achieve the initial condition q(t = 0) = 1, and p can be expressed in terms of q:.

Black stain and dental caries in Filipino schoolchildren.

NARCIS (Netherlands)

Heinrich-Weltzien, R.; Monse, B.; Palenstein Helderman, W.H. van

2009-01-01

Black stain is defined as dark pigmented exogenous substance in lines or dots parallel to the gingival margin and firmly adherent to the enamel at the cervical third of the tooth crowns in the primary and permanent dentition. OBJECTIVES: This study was conducted to assess the prevalence of black

Absolute and relative-rate measurement of the rate coefficient for reaction of perfluoro ethyl vinyl ether (C2F5OCF[double bond, length as m-dash]CF2) with OH.

Science.gov (United States)

Srinivasulu, G; Bunkan, A J C; Amedro, D; Crowley, J N

2018-01-31

The rate coefficient (k 1 ) for the reaction of OH radicals with perfluoro ethyl vinyl ether (PEVE, C 2 F 5 OCF[double bond, length as m-dash]CF 2 ) has been measured as a function of temperature (T = 207-300 K) using the technique of pulsed laser photolysis with detection of OH by laser-induced fluorescence (PLP-LIF) at pressures of 50 or 100 Torr N 2 bath gas. In addition, the rate coefficient was measured at 298 K and in one atmosphere of air by the relative-rate technique with loss of PEVE and reference reactant monitored in situ by IR absorption spectroscopy. The rate coefficient has a negative temperature dependence which can be parameterized as: k 1 (T) = 6.0 × 10 -13  exp[(480 ± 38/T)] cm 3 molecule -1 s -1 and a room temperature value of k 1 (298 K) = (3.0 ± 0.3) × 10 -12 cm 3 molecule -1 s -1 . Highly accurate rate coefficients from the PLP-LIF experiments were achieved by optical on-line measurements of PEVE and by performing the measurements at two different apparatuses. The large rate coefficient and the temperature dependence indicate that the reaction proceeds via OH addition to the C[double bond, length as m-dash]C double bond, the high pressure limit already being reached at 50 Torr N 2 . Based on the rate coefficient and average OH levels, the atmospheric lifetime of PEVE was estimated to be a few days.

Crossing the Color Line: Black Professional Men’s Development of Interracial Social Networks

Directory of Open Access Journals (Sweden)

Adia Harvey Wingfield

2014-05-01

Full Text Available Sociologists have established that social networks often play an important role in hiring, promotions, and occupational mobility. For black workers, however, social networks can be racialized in ways that work to their disadvantage. In this paper, I consider how black professional men develop and maintain interracial social networks with white men and women. I argue that these networks are shaped by intersections of race and gender and are intentionally constructed in response to black professional men’s perceptions of their positioning within male-dominated occupations. Specifically, this paper examines how black men establish social networks with white men, their perceptions of how diverging levels of social capital shape these networks compared to their white male peers, and their observations of ways that women are less advantaged than they are in constructing social networks.

Charged topological black hole pair creation

International Nuclear Information System (INIS)

Mann, R.B.

1998-01-01

I examine the pair creation of black holes in space-times with a cosmological constant of either sign. I consider cosmological C-metrics and show that the conical singularities in this metric vanish only for three distinct classes of black hole metric, two of which have compact event horizons on each spatial slice. One class is a generalization of the Reissner-Nordstroem (anti-)de Sitter black holes in which the event horizons are the direct product of a null line with a 2-surface with topology of genus g. The other class consists of neutral black holes whose event horizons are the direct product of a null conoid with a circle. In the presence of a domain wall, black hole pairs of all possible types will be pair created for a wide range of mass and charge, including even negative mass black holes. I determine the relevant instantons and Euclidean actions for each case. (orig.)

Significance of power average of sinusoidal and non-sinusoidal ...

Indian Academy of Sciences (India)

2016-06-08

Jun 8, 2016 ... PG & Research Department of Physics, Nehru Memorial College (Autonomous),. Puthanampatti .... for long time intervals, the periodic or chaotic behaviour ..... square force (short dashed line), sawtooth force (long dashed.

[Analysis of the population structure of the Black Forest Draught Horse].

Science.gov (United States)

Aberle, Kerstin; Wrede, Jörn; Distl, Ottmar

2003-01-01

Gene contributions of foreign populations as well as coefficients of inbreeding and relationship were evaluated in 699 Black Forest Draught horses of Baden-Württemberg actually registered in the year 2002. Based on nearly complete 5-generation-pedigrees and after taking into account the remaining incompleteness, the mean coefficient of inbreeding for the total population was 6.5%. The recently by incrossing with different breeds newly established lines of stallions showed significantly lower mean coefficients of inbreeding. High rates of inbreeding of about 1.6% in the last five generations could also be faced by incrossing stallions of foreign coldblooded populations what resulted in a decrease of inbreeding in the last generation. In the total population the mean degree of relationship was 16%. The mean degree of relationships within lines of stallions was between 18.3 and 26.8%. The coefficients of relationships between lines of stallions varied between 5.1 and 16.6%. Especially, the newly established lines of stallions showed a lower mean degree of relationships to the other different lines of stallions. The proportion of purebred Black Forest Draught horses in the total population was nearly 70%. Assuming that most animals of unknown origin were purebred, the proportion of purebred Black Forest Draught horses reached about 90%. Austrian Noric, Swiss Freiberg and South German Coldblood stallions were the most important contributors to the Black Forest Draught horse population.

The End of the Lines for OX 169: No Binary Broad-Line Region

Science.gov (United States)

Halpern, J. P.; Eracleous, M.

2000-03-01

We show that unusual Balmer emission-line profiles of the quasar OX 169, frequently described as either self-absorbed or double peaked, are actually neither. The effect is an illusion resulting from two coincidences. First, the forbidden lines are quite strong and broad. Consequently, the [N II] λ6583 line and the associated narrow-line component of Hα present the appearance of twin Hα peaks. Second, the redshift of 0.2110 brings Hβ into coincidence with Na I D at zero redshift, and ISM absorption in Na I D divides the Hβ emission line. In spectra obtained over the past decade, we see no substantial change in the character of the line profiles and no indication of intrinsic double-peaked structure. The Hγ, Mg II, and Lyα emission lines are single peaked, and all of the emission-line redshifts are consistent once they are correctly attributed to their permitted and forbidden-line identifications. A systematic shift of up to 700 km s-1 between broad and narrow lines is seen, but such differences are common and could be due to gravitational and transverse redshift in a low-inclination disk. Stockton & Farnham had called attention to an apparent tidal tail in the host galaxy of OX 169 and speculated that a recent merger had supplied the nucleus with a coalescing pair of black holes that was now revealing its existence in the form of two physically distinct broad-line regions. Although there is no longer any evidence for two broad emission-line regions in OX 169, binary black holes should form frequently in galaxy mergers, and it is still worthwhile to monitor the radial velocities of emission lines that could supply evidence of their existence in certain objects.

Poverty Status and Childhood Asthma in White and Black Families: National Survey of Children’s Health

Directory of Open Access Journals (Sweden)

Shervin Assari

2018-06-01

Full Text Available Background: Living above the poverty line reduces the risk of physical illnesses, including childhood asthma (CA. Minorities’ Diminished Return theory, however, suggests that the protective effects of socioeconomic status (SES on health are weaker for racial minorities than White families. It is unknown whether the association between SES and CA differs for White and Black families. Aims: Using a national sample, the current study compared Black and White families for the association between living above the poverty line and CA. Methods: Data came from the National Survey of Children’s Health (NSCH, 2003–2004, a national telephone survey. A total of 86,537 Black or White families with children (17 years old or younger were included in the study. This sample was composed of 76,403 White (88.29% and 10,134 Black (11.71% families. Family SES (living above the poverty line was the independent variable. The outcome was CA, reported by the parent. Age, gender, and childhood obesity were the covariates. Race was conceptualized as the moderator. A number of multivariable logistic regressions were used in the pooled sample and specific to each race for data analysis. Results: In the pooled sample, living above the poverty line was associated with lower odds of CA. An interaction was found between race and living above the poverty line on odds of CA, indicating a smaller association for Black compared to White families. Although race-stratified logistic regressions showed negative associations between living above the poverty line and CA in both White and Black families, the magnitude of this negative association was larger for White than Black families. Conclusions: The health gain from living above the poverty line may be smaller for Black than White families. Due to the existing Minorities’ Diminished Return, policies that merely reduce the racial gap in SES may not be sufficient in eliminating racial health disparities in the United States

Iron Kα line of boson stars

Energy Technology Data Exchange (ETDEWEB)

Cao, Zheng; Zhou, Menglei; Bambi, Cosimo [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 220 Handan Road, 200433 Shanghai (China); Cárdenas-Avendaño, Alejandro [Programa de Matemática, Fundación Universitaria Konrad Lorenz, Carrera 9 Bis No. 62-43, 110231 Bogotá (Colombia); Herdeiro, Carlos A.R.; Radu, Eugen, E-mail: zcao13@fudan.edu.cn, E-mail: alejandro.cardenasa@konradlorenz.edu.co, E-mail: mlzhou13@fudan.edu.cn, E-mail: bambi@fudan.edu.cn, E-mail: herdeiro@ua.pt, E-mail: eugen.radu@ua.pt [Departamento de Física da Universidade de Aveiro, and Center for Research and Development in Mathematics and Applications (CIDMA), Campus de Santiago, 3810-183 Aveiro (Portugal)

2016-10-01

The present paper is a sequel to our previous work [1] in which we studied the iron Kα line expected in the reflection spectrum of Kerr black holes with scalar hair. These metrics are solutions of Einstein's gravity minimally coupled to a massive, complex scalar field. They form a continuous bridge between a subset of Kerr black holes and a family of rotating boson stars depending on one extra parameter, the dimensionless scalar hair parameter q , ranging from 0 (Kerr black holes) to 1 (boson stars). Here we study the limiting case q = 1, corresponding to rotating boson stars. For comparison, spherical boson stars are also considered. We simulate observations with XIS/Suzaku. Using the fact that current observations are well fit by the Kerr solution and thus requiring that acceptable alternative compact objects must be compatible with a Kerr fit, we find that some boson star solutions are relatively easy to rule out as potential candidates to explain astrophysical black holes, while other solutions, which are neither too dilute nor too compact are more elusive and we argue that they cannot be distinguished from Kerr black holes by the analysis of the iron line with current X-ray facilities.

Iron Kα line of boson stars

International Nuclear Information System (INIS)

Cao, Zheng; Zhou, Menglei; Bambi, Cosimo; Cárdenas-Avendaño, Alejandro; Herdeiro, Carlos A.R.; Radu, Eugen

2016-01-01

The present paper is a sequel to our previous work [1] in which we studied the iron Kα line expected in the reflection spectrum of Kerr black holes with scalar hair. These metrics are solutions of Einstein's gravity minimally coupled to a massive, complex scalar field. They form a continuous bridge between a subset of Kerr black holes and a family of rotating boson stars depending on one extra parameter, the dimensionless scalar hair parameter q , ranging from 0 (Kerr black holes) to 1 (boson stars). Here we study the limiting case q = 1, corresponding to rotating boson stars. For comparison, spherical boson stars are also considered. We simulate observations with XIS/Suzaku. Using the fact that current observations are well fit by the Kerr solution and thus requiring that acceptable alternative compact objects must be compatible with a Kerr fit, we find that some boson star solutions are relatively easy to rule out as potential candidates to explain astrophysical black holes, while other solutions, which are neither too dilute nor too compact are more elusive and we argue that they cannot be distinguished from Kerr black holes by the analysis of the iron line with current X-ray facilities.

Demonstrator of atmospheric reentry system with hyperbolic velocity—DASH

Science.gov (United States)

Morita, Yasuhiro; Kawaguchi, Jun'ichiro; Inatani, Yoshifumi; Abe, Takashi

2003-01-01

Among a wide variety of challenging projects planned for the coming decade is the MUSES-C mission designed by the ISAS of Japan. Despite huge amount of data collected by the previous interplanetary spacecraft and probes, the origin and evolution of the solar system still remains unveiled due to their limited information. Thus, our concern has been directed toward a sample return to carry sample from an asteroid back to the earth, which will contribute to better understanding of the system. One of the keys to success is considered the reentry technology with hyperbolic velocity, which has not been demonstrated yet. With this as background, the demonstrator of atmospheric reentry system with hyperbolic velocity, DASH, has been given a commitment to demonstrate the high-speed reentry technology, which will be launched in summer of next year by Japan's H-IIA rocket in a piggyback configuration. The spaceship, composed of a reentry capsule and its carrier, will be injected into a geostationary transfer orbit (GTO) and after several revolutions it will deorbit by burn of a solid propellant deorbit motor. The capsule, identical to that of the sample return mission, can experience the targeted level of thermal environment even from the GTO by tracing a specially designed reentry trajectory.

Quantum dash based single section mode locked lasers for photonic integrated circuits.

Science.gov (United States)

Joshi, Siddharth; Calò, Cosimo; Chimot, Nicolas; Radziunas, Mindaugas; Arkhipov, Rostislav; Barbet, Sophie; Accard, Alain; Ramdane, Abderrahim; Lelarge, Francois

2014-05-05

We present the first demonstration of an InAs/InP Quantum Dash based single-section frequency comb generator designed for use in photonic integrated circuits (PICs). The laser cavity is closed using a specifically designed Bragg reflector without compromising the mode-locking performance of the self pulsating laser. This enables the integration of single-section mode-locked laser in photonic integrated circuits as on-chip frequency comb generators. We also investigate the relations between cavity modes in such a device and demonstrate how the dispersion of the complex mode frequencies induced by the Bragg grating implies a violation of the equi-distance between the adjacent mode frequencies and, therefore, forbids the locking of the modes in a classical Bragg Device. Finally we integrate such a Bragg Mirror based laser with Semiconductor Optical Amplifier (SOA) to demonstrate the monolithic integration of QDash based low phase noise sources in PICs.

Brazilian dietary patterns and the dietary approaches to stop hypertension (DASH) diet-relationship with metabolic syndrome and newly diagnosed diabetes in the ELSA-Brasil study.

Science.gov (United States)

Drehmer, Michele; Odegaard, Andrew O; Schmidt, Maria Inês; Duncan, Bruce B; Cardoso, Letícia de Oliveira; Matos, Sheila M Alvim; Molina, Maria Del Carmen B; Barreto, Sandhi M; Pereira, Mark A

2017-01-01

Studies evaluating dietary patterns, including the DASH diet, and their relationship with the metabolic syndrome and diabetes may help to understand the role of dairy products (low fat or full fat) in these conditions. Our aim is to identify dietary patterns in Brazilian adults and compare them with the (DASH) diet quality score in terms of their associations with metabolic syndrome and newly diagnosed diabetes in the Brazilian Longitudinal Study of Adult Health-the ELSA-Brasil study. The ELSA-Brasil is a multicenter cohort study comprising 15,105 civil servants, aged 35-74 years at baseline (2008-2010). Standardized interviews and exams were carried out, including an OGTT. We analyzed baseline data for 10,010 subjects. Dietary patterns were derived by principal component analysis. Multivariable logistic regression investigated associations of dietary patterns with metabolic syndrome and newly diagnosed diabetes and multivariable linear regression with components of metabolic syndrome. After controlling for potential confounders, we observed that greater adherence to the Common Brazilian meal pattern (white rice, beans, beer, processed and fresh meats), was associated with higher frequencies of newly diagnosed diabetes, metabolic syndrome and all of its components, except HDL-C. Participants with greater intake of a Common Brazilian fast foods/full fat dairy/milk based desserts pattern presented less newly diagnosed diabetes. An inverse association was also seen between the DASH Diet pattern and the metabolic syndrome, blood pressure and waist circumference. Diet, light foods and beverages/low fat dairy pattern was associated with more prevalence of both outcomes, and higher fasting glucose, HDL-C, waist circumference (among men) and lower blood pressure. Vegetables/fruit dietary pattern did not protect against metabolic syndrome and newly diagnosed diabetes but was associated with lower waist circumference. The inverse associations found for the dietary pattern

Experimental investigation of the optical injection locking dynamics in single section quantum-dash Fabry-Pérot laser diode for packet based clock recovery applications

NARCIS (Netherlands)

Maldonado-Basilio, R.; Parra-Cetina, J.; Latkowski, S.; Calabretta, N.; Landais, P.

2012-01-01

An experimental study of the dynamics of a quantum-dash Fabry-Pérot passively mode-locked laser diode is presented. Firstly, the switching on and off characteristic times of the mode-locking mechanism with pulsed biasing current are assessed. Secondly, the locking and unlocking characteristic times

The Weak Gravity Conjecture and the axionic black hole paradox

Science.gov (United States)

Hebecker, Arthur; Soler, Pablo

2017-09-01

In theories with a perturbatively massless 2-form (dual to an axion), a paradox may arise in the process of black hole evaporation. Schwarzschild black holes can support a non-trivial Wilson-line-type field, the integral of the 2-form around their horizon. After such an `axionic black hole' evaporates, the Wilson line must be supported by the corresponding 3-form field strength in the region formerly occupied by the black hole. In the limit of small axion decay-constant f, the energy required for this field configuration is too large. Thus, energy cannot be conserved in the process of black hole evaporation. The natural resolution of this paradox is through the presence of light strings, which allow the black hole to "shed" its axionic hair sufficiently early. This gives rise to a new Weak-Gravity-type argument in the 2-form context: small coupling, in this case f , enforces the presence of light strings or a low cutoff. We also discuss how this argument may be modified in situations where the weak coupling regime is achieved in the low-energy effective theory through an appropriate gauging of a model with a vector field and two 2-forms.

Development of 2.8 V Ketjen black supercapacitors with high rate capabilities for AC line filtering

Science.gov (United States)

Yoo, Yongju; Park, Jinwoo; Kim, Min-Seop; Kim, Woong

2017-08-01

Supercapacitors are generally more compact than conventional bulky aluminum electrolytic capacitors (AECs). Replacement of AECs with supercapacitors can lead to miniaturization of electronic devices. However, even state-of-the-art supercapacitors developed in laboratories are superior to or competitive with AECs only in low voltage applications (<∼40 V). In order to improve the voltage limits of current supercapacitors, we have incorporated Ketjen black (KB) as an electrode material. Utilizing the open pore structure and the graphitic nature of KB, we demonstrate that the voltage limit can be extended to 53 V. The KB supercapacitor exhibits excellent areal capacitance, cell voltage, and phase angle values of ∼574 μF cm-2, 2.8 V, and ∼-80°, respectively. In addition, we demonstrate that an AC line filtering circuit with three supercapacitors connected in series can extend the application voltage without significant sacrifice in rate capability (ϕ ∼ -77° at 120 Hz). On the other hand, KBs are much less expensive than carbon materials previously demonstrated for AC line filtering and hence are very attractive for practical applications. We believe that this demonstration of high-performance supercapacitors made from low-cost carbon materials is both scientifically interesting and important for practical applications.

Electron spin resonance characterization of radical components in irradiated black pepper skin and core

International Nuclear Information System (INIS)

Yamaoki, Rumi; Kimura, Shojiro; Ohta, Masatoshi

2011-01-01

Characteristics of free radical components of irradiated black pepper fruit (skin) and the pepper seed (core) were analyzed using electron spin resonance. A weak signal near g=2.005 was observed in black pepper before irradiation. Complex spectra near g=2.005 with three lines (the skin) or seven lines (the core) were observed in irradiated black pepper (both end line width; ca. 6.8 mT). The spectral intensities decreased considerably at 30 days after irradiation, and continued to decrease steadily thereafter. The spectra simulated on the basis of the content and the stability of radical components derived from plant constituents, including fiber, starch, polyphenol, mono- and disaccharide, were in good agreement with the observed spectra. Analysis showed that the signal intensities derived from fiber in the skin for an absorbed dose were higher, and the rates of decrease were lower, than that in the core. In particular, the cellulose radical component in the skin was highly stable. - Highlights: → We identified the radical components in irradiated black pepper skin and core. → The ESR spectra near g=2.005 with 3-7 lines were emerged after irradiation. → Spectra simulated basing on the content and the stability of radical from the plant constituents. → Cellulose radical component in black pepper skin was highly stable. → Single signal near g=2.005 was the most stable in black pepper core.

Impact mortality of black storks (Ciconia nigra) on medium-voltage overhead power lines in Rheinland-Pfalz; Anflugverluste von Schwarzstoerchen (Ciconia nigra) an Mittelspannungsfreileitungen in Rheinland-Pfalz

Energy Technology Data Exchange (ETDEWEB)

Hormann, M.; Richarz, K. [Staatliche Vogelschutzwarte fuer Hessen, Rheinland-Pfalz und Saarland, Frankfurt am Main (Germany)

1997-12-01

The small breeding population of black storks (Ciconia nigra), which had been growing steadily since first nesting in Rhineland-Palantinate in 1982, has been observably decreasing again since 1993, particularly in its main territories. The high mortality of, for the most part, juvenile black storks resulting from collision with a overhead power line (OHL) is described (30 collision victims since the mid-1980s). The energy utilities are called upon to install underground cables on the relevant sections of the power lines in addition to modifying hazardous types of towers in order to reduce the high bird mortality rate. (orig.) [Deutsch] Fuer den seit einer Erstbrut 1982 in Rheinland-Pfalz stetig angestiegenen kleinen Brutbestand des Schwarzstorchs (Ciconia nigra) sind vor allem in seinen Kerngebieten seit 1993 wieder Bestandsrueckgaenge zu verzeichnen. Die hohen Verluste ueberwiegend junger Schwarzstoerche durch Anflug an Mittel- und Niederspannungsfreileitungen (seit Mitte der 80er Jahre 30 Schwarzstoerche als Anflugopfer) werden beschrieben. Neben der Entschaerfung gefaehrlicher Masttypen wird zur Vermeidung der hohen Anflugverluste eine Erdverkabelung der kritischen Leitungsabschnitte gefordert. (orig.)

The effect of nuclear gas distribution on the mass determination of supermassive black holes

Science.gov (United States)

Mejía-Restrepo, J. E.; Lira, P.; Netzer, H.; Trakhtenbrot, B.; Capellupo, D. M.

2018-01-01

Supermassive black holes reside in the nuclei of most galaxies. During their active episodes, black holes are powered by accretion discs where gravitational energy is converted into radiation1. Accurately determining black hole masses is key to understand how the population evolves over time and how the black holes relate to their host galaxies2-4. Beyond the local universe, z ≳ 0.2, the mass is commonly estimated assuming a virialized motion of gas in the close vicinity of the active black holes, traced through broad emission lines5,6. However, this procedure has uncertainties associated with the unknown distribution of the gas clouds. Here, we show that the black hole masses derived from the properties of the accretion disk and virial mass estimates differ by a factor that is inversely proportional to the width of the broad emission lines. This leads to virial mass misestimations up to a factor of six. Our results suggest that a planar gas distribution that is inclined with respect to the line of sight may account for this effect. However, radiation pressure effects on the distribution of gas can also reproduce our results. Regardless of the physical origin, our findings contribute to mitigating the uncertainties in current black hole mass estimations and, in turn, will help us to better understand the evolution of distant supermassive black holes and their host galaxies.

The trochlear cleft: the ''black line'' of the trochlear trough

International Nuclear Information System (INIS)

Wissman, Robert D.; Nepute, Joshua; Fischer, Nathaniel von; Radhakrishnan, Rupa; Hendry, Daniel; Ingalls, Jerrell; Kenter, Keith

2012-01-01

The ''cartilage black line sign'' is a recently described T2 dark cartilage lesion that we have identified appearing as a cleft in the trochlear trough. The purpose of our study was to define the MR imaging characteristics of a trochlear cleft, determine its incidence, and correlate the MR findings with arthroscopy. A total of 1,300 consecutive MR examinations of the knee were retrospectively reviewed by consensus of two fellowship-trained musculoskeletal radiologists. The MR imaging characteristics and location of a trochlear cleft were determined. Imaging results were compared to arthroscopy when available. Patient age and gender were compared to 25 randomly selected control patients without trochlear clefts. A total of 25 (1.9%) individuals (11 females and 14 males; age range 19-45 years; mean age 28 years) were diagnosed with a trochlear cleft. The control group consisted of 11 females and 14 males; age range 19-83 years; mean age 46 years. Mean cleft length was 7 mm (range 6-12 mm); cleft location was consistently in the lower trochlear trough. No full-thickness cartilage defects were identified in the eight individuals in whom arthroscopic correlation was available. A grade 2 cartilage lesion was identified in a single individual; another progressed from grade 0 to a full-thickness trochlear lesion over an 8-month interval. Eight individuals were athletes. No significant difference in gender was noted between the two groups, however, the study group was significantly younger p < 0.0001. A trochlear cleft is a rare finding in young active individuals. It most likely indicates an incomplete cartilage fissure which may rarely progress to a full-thickness defect. (orig.)

Magnitude Differences in Bioactive Compounds, Chemical Functional Groups, Fatty Acid Profiles, Nutrient Degradation and Digestion, Molecular Structure, and Metabolic Characteristics of Protein in Newly Developed Yellow-Seeded and Black-Seeded Canola Lines.

Science.gov (United States)

Theodoridou, Katerina; Zhang, Xuewei; Vail, Sally; Yu, Peiqiang

2015-06-10

Recently, new lines of yellow-seeded (CS-Y) and black-seeded canola (CS-B) have been developed with chemical and structural alteration through modern breeding technology. However, no systematic study was found on the bioactive compounds, chemical functional groups, fatty acid profiles, inherent structure, nutrient degradation and absorption, or metabolic characteristics between the newly developed yellow- and black-seeded canola lines. This study aimed to systematically characterize chemical, structural, and nutritional features in these canola lines. The parameters accessed include bioactive compounds and antinutrition factors, chemical functional groups, detailed chemical and nutrient profiles, energy value, nutrient fractions, protein structure, degradation kinetics, intestinal digestion, true intestinal protein supply, and feed milk value. The results showed that the CS-Y line was lower (P ≤ 0.05) in neutral detergent fiber (122 vs 154 g/kg DM), acid detergent fiber (61 vs 99 g/kg DM), lignin (58 vs 77 g/kg DM), nonprotein nitrogen (56 vs 68 g/kg DM), and acid detergent insoluble protein (11 vs 35 g/kg DM) than the CS-B line. There was no difference in fatty acid profiles except C20:1 eicosenoic acid content (omega-9) which was in lower in the CS-Y line (P structure spectral profile, there were no significant differences in functional groups of amides I and II, α helix, and β-sheet structure as well as their ratio between the two new lines, indicating no difference in protein structure makeup and conformation between the two lines. In terms of energy values, there were significant differences in total digestible nutrient (TDN; 149 vs 133 g/kg DM), metabolizable energy (ME; 58 vs 52 MJ/kg DM), and net energy for lactation (NEL; 42 vs 37 MJ/kg DM) between CS-Y and CS-B lines. For in situ rumen degradation kinetics, the two lines differed in soluble fraction (S; 284 vs 341 g/kg CP), potential degradation fraction (D; 672 vs 590 g/kg CP), and effective degraded

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

Science.gov (United States)

Kulis, Stephen; Shaw, Heather; Chong, Yinong

2000-01-01

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

Probing strong-field general relativity near black holes

CERN Multimedia

CERN. Geneva; Alvarez-Gaumé, Luís

2005-01-01

Nature has sprinkled black holes of various sizes throughout the universe, from stellar mass black holes in X-ray sources to supermassive black holes of billions of solar masses in quasars. Astronomers today are probing the spacetime near black holes using X-rays, and gravitational waves will open a different view in the near future. These tools give us an unprecedented opportunity to test ultra-strong-field general relativity, including the fundamental theorem of the uniqueness of the Kerr metric and Roger Penrose's cosmic censorship conjecture. Already, fascinating studies of spectral lines are showing the extreme gravitational lensing effects near black holes and allowing crude measurements of black hole spin. When the ESA-NASA gravitational wave detector LISA begins its observations in about 10 years, it will make measurements of dynamical spacetimes near black holes with an accuracy greater even than that which theoreticians can reach with their computations today. Most importantly, when gravitational wa...

Blood-feeding Behaviors of Anopheles stephensi But Not Phlebotomus papatasi are Influenced by Actively Warming Guinea Pigs (Cavia porcellus) Under General Anesthesia

Science.gov (United States)

2015-01-01

differential biting behaviors on warmed or unwarmed guinea pig hosts. (A) Warmed (dashed line with square time points) and control (solid line with circle time ...Fig. 2. Sand flies do not display differential biting behaviors on warmed or unwarmed guinea pig hosts. (A) Warmed (dashed line with square time ...books/NBK54050/ Peterson D, Brown A. 1951. Studies of the responses of the female Aedes mosquito. Part III. The response of Aedes aegypti (L.) to a warm

Black-hole driven winds

International Nuclear Information System (INIS)

Punsly, B.M.

1988-01-01

This dissertation is a study of the physical mechanism that allows a large scale magnetic field to torque a rapidly rotating, supermassive black hole. This is an interesting problem as it has been conjectured that rapidly rotating black holes are the central engines that power the observed extragalactic double radio sources. Axisymmetric solutions of the curved space-time version of Maxwell's equations in the vacuum do not torque black holes. Plasma must be introduced for the hole to mechanically couple to the field. The dynamical aspect of rotating black holes that couples the magnetic field to the hole is the following. A rotating black hole forces the external geometry of space-time to rotate (the dragging of inertial frames). Inside of the stationary limit surface, the ergosphere, all physical particle trajectories must appear to rotate in the same direction as the black hole as viewed by the stationary observers at asymptotic infinity. In the text, it is demonstrated how plasma that is created on field lines that thread both the ergosphere and the equatorial plane will be pulled by gravity toward the equator. By the aforementioned properties of the ergosphere, the disk must rotate. Consequently, the disk acts like a unipolar generator. It drives a global current system that supports the toroidal magnetic field in an outgoing, magnetically dominated wind. This wind carries energy (mainly in the form of Poynting flux) and angular momentum towards infinity. The spin down of the black hole is the ultimate source of this energy and angular momentum flux

Quantum-gravity fluctuations and the black-hole temperature

Energy Technology Data Exchange (ETDEWEB)

Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Institute, Jerusalem (Israel)

2015-05-15

Bekenstein has put forward the idea that, in a quantum theory of gravity, a black hole should have a discrete energy spectrum with concomitant discrete line emission. The quantized black-hole radiation spectrum is expected to be very different from Hawking's semi-classical prediction of a thermal black-hole radiation spectrum. One naturally wonders: Is it possible to reconcile the discrete quantum spectrum suggested by Bekenstein with the continuous semi-classical spectrum suggested by Hawking? In order to address this fundamental question, in this essay we shall consider the zero-point quantum-gravity fluctuations of the black-hole spacetime. In a quantum theory of gravity, these spacetime fluctuations are closely related to the characteristic gravitational resonances of the corresponding black-hole spacetime. Assuming that the energy of the black-hole radiation stems from these zero-point quantum-gravity fluctuations of the black-hole spacetime, we derive the effective temperature of the quantized black-hole radiation spectrum. Remarkably, it is shown that this characteristic temperature of the discrete (quantized) black-hole radiation agrees with the well-known Hawking temperature of the continuous (semi-classical) black-hole spectrum. (orig.)

Quantum-gravity fluctuations and the black-hole temperature

International Nuclear Information System (INIS)

Hod, Shahar

2015-01-01

Bekenstein has put forward the idea that, in a quantum theory of gravity, a black hole should have a discrete energy spectrum with concomitant discrete line emission. The quantized black-hole radiation spectrum is expected to be very different from Hawking's semi-classical prediction of a thermal black-hole radiation spectrum. One naturally wonders: Is it possible to reconcile the discrete quantum spectrum suggested by Bekenstein with the continuous semi-classical spectrum suggested by Hawking? In order to address this fundamental question, in this essay we shall consider the zero-point quantum-gravity fluctuations of the black-hole spacetime. In a quantum theory of gravity, these spacetime fluctuations are closely related to the characteristic gravitational resonances of the corresponding black-hole spacetime. Assuming that the energy of the black-hole radiation stems from these zero-point quantum-gravity fluctuations of the black-hole spacetime, we derive the effective temperature of the quantized black-hole radiation spectrum. Remarkably, it is shown that this characteristic temperature of the discrete (quantized) black-hole radiation agrees with the well-known Hawking temperature of the continuous (semi-classical) black-hole spectrum. (orig.)

Non-linear Q-clouds around Kerr black holes

International Nuclear Information System (INIS)

Herdeiro, Carlos; Radu, Eugen; Rúnarsson, Helgi

2014-01-01

Q-balls are regular extended ‘objects’ that exist for some non-gravitating, self-interacting, scalar field theories with a global, continuous, internal symmetry, on Minkowski spacetime. Here, analogous objects are also shown to exist around rotating (Kerr) black holes, as non-linear bound states of a test scalar field. We dub such configurations Q-clouds. We focus on a complex massive scalar field with quartic plus hexic self-interactions. Without the self-interactions, linear clouds have been shown to exist, in synchronous rotation with the black hole horizon, along 1-dimensional subspaces – existence lines – of the Kerr 2-dimensional parameter space. They are zero modes of the superradiant instability. Non-linear Q-clouds, on the other hand, are also in synchronous rotation with the black hole horizon; but they exist on a 2-dimensional subspace, delimited by a minimal horizon angular velocity and by an appropriate existence line, wherein the non-linear terms become irrelevant and the Q-cloud reduces to a linear cloud. Thus, Q-clouds provide an example of scalar bound states around Kerr black holes which, generically, are not zero modes of the superradiant instability. We describe some physical properties of Q-clouds, whose backreaction leads to a new family of hairy black holes, continuously connected to the Kerr family

Self-Consistent Dynamical Model of the Broad Line Region

Energy Technology Data Exchange (ETDEWEB)

Czerny, Bozena [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Li, Yan-Rong [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China); Sredzinska, Justyna; Hryniewicz, Krzysztof [Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw (Poland); Panda, Swayam [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw (Poland); Wildy, Conor [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Karas, Vladimir, E-mail: bcz@cft.edu.pl [Astronomical Institute, Czech Academy of Sciences, Prague (Czech Republic)

2017-06-22

We develop a self-consistent description of the Broad Line Region based on the concept of a failed wind powered by radiation pressure acting on a dusty accretion disk atmosphere in Keplerian motion. The material raised high above the disk is illuminated, dust evaporates, and the matter falls back toward the disk. This material is the source of emission lines. The model predicts the inner and outer radius of the region, the cloud dynamics under the dust radiation pressure and, subsequently, the gravitational field of the central black hole, which results in asymmetry between the rise and fall. Knowledge of the dynamics allows us to predict the shapes of the emission lines as functions of the basic parameters of an active nucleus: black hole mass, accretion rate, black hole spin (or accretion efficiency) and the viewing angle with respect to the symmetry axis. Here we show preliminary results based on analytical approximations to the cloud motion.

Self-Consistent Dynamical Model of the Broad Line Region

Directory of Open Access Journals (Sweden)

Bozena Czerny

2017-06-01

Full Text Available We develop a self-consistent description of the Broad Line Region based on the concept of a failed wind powered by radiation pressure acting on a dusty accretion disk atmosphere in Keplerian motion. The material raised high above the disk is illuminated, dust evaporates, and the matter falls back toward the disk. This material is the source of emission lines. The model predicts the inner and outer radius of the region, the cloud dynamics under the dust radiation pressure and, subsequently, the gravitational field of the central black hole, which results in asymmetry between the rise and fall. Knowledge of the dynamics allows us to predict the shapes of the emission lines as functions of the basic parameters of an active nucleus: black hole mass, accretion rate, black hole spin (or accretion efficiency and the viewing angle with respect to the symmetry axis. Here we show preliminary results based on analytical approximations to the cloud motion.

Reducing BWR O and M costs through on-line performance monitoring

International Nuclear Information System (INIS)

Jonas, T.; Gross, R.; Logback, F.; Josyula, R.

1995-01-01

Competition in the electric power industry has placed significant emphasis on reducing operating and maintenance (O and M) costs at nuclear facilities. Therefore, on-line performance monitoring to locate power losses for boiling water reactor (BWR) plants is creating tremendous interest. In addition, the ability to automate activities such as data collection, analysis, and reporting increases the efficiency of plant engineers and gives them more time to concentrate on solving plant efficiency problems. This capability is now available with a unique software product called GEBOPS. GE Nuclear Energy, in conjunction with Joint Venture partner Black and Veatch, has undertaken development of the General Electric/Black and Veatch On-line Performance System (GEBOPS), an on-line performance monitoring system for BWR plants. The experience and expertise of GE Nuclear Energy with BWR plants, coupled with the proven on-line monitoring software development experience and capability of Black and Veatch, provide the foundation for a unique product which addresses the needs of today's BWR plants

Fate of black branes in Einstein-Gauss-Bonnet gravity

International Nuclear Information System (INIS)

Suranyi, P.; Wijewardhana, L. C. R.; Vaz, C.

2009-01-01

Black branes are studied in Einstein-Gauss-Bonnet gravity. Evaporation drives black branes toward one of two singularities depending on the sign of α, the Gauss-Bonnet coupling. For positive α and sufficiently large ratio √(α)/L, where L/2π is the radius of compactification, black branes avoid the Gregory-Laflamme (GL) instability before reaching a critical state. No black branes with the radius of horizon smaller than the critical value can exist. Approaching the critical state branes have a nonzero Hawking temperature. For negative α all black branes encounter the GL instability. No black branes may exist outside of the interval of the critical values 0≤β h 2 and r h is the radius of horizon of the black brane. The first order phase transition line of GL transitions ends in a second order phase transition point at β=0.

Constraints on the evolution of black hole spin due to magnetohydrodynamic accretion

International Nuclear Information System (INIS)

Takahashi, Masaaki; Tomimatsu, Akira

2008-01-01

Stationary and axisymmetric ideal magnetohydrodynamic (MHD) accretion onto a black hole is studied analytically. The accreting plasma ejected from a plasma source with low velocity must be superfast magnetosonic before passing through the event horizon. We work out and apply a trans-fast magnetosonic solution without detailed analysis of the regularity conditions at the magnetosonic point, by introducing the bending angle β of the magnetic field line, which is the ratio of the toroidal and poloidal components of the magnetic field. To accrete onto a black hole, the trans-magnetosonic solution has some restrictions on β, which are related to the field-aligned parameters of the MHD flows. One of the restrictions gives the boundary condition at the event horizon for the inclination of a magnetic field line. We find that this inclination is related to the energy and angular momentum transport to the black hole. Then, we discuss the spin-up/down process of a rotating black hole by cold MHD inflows in a secular evolution time scale. There are two asymptotic states for the spin evolution. One is that the angular velocity of the black hole approaches to that of the magnetic field line, and the other is that the spin-up effect by the positive angular momentum influx and the spin-down effect by the energy influx (as the mass-energy influx) are canceled. We also show that the MHD inflows prevents the evolution to the maximally rotating black hole.

Shaping Globular Clusters with Black Holes

Science.gov (United States)

Kohler, Susanna

2018-03-01

, single and binary star evolution, galactic tides, and multi-body encounters. From their grid of models with varying input parameters, the authors then determine which fit best to NGC 3201s final observational properties.Surface brightness profiles for all globular-cluster models at late times compared to observations of NGC 3201 (yellow circles). Blue lines represent models with few retained black holes; black lines represent models with many retained black holes. [Kremer et al. 2018]Retention MattersKremer and collaborators find that the models that best represent NGC 3201 all retain more than 200 black holes at the end of the simulation; models that lost too many black holes due to natal kicks did not match observations of NGC 3201 as well. The models with large numbers of retained black holes also harbored binaries just like the one recently detected in NGC 3201.Models that retain few black holes, on the other hand, may instead be good descriptions of so-called core-collapsed globular clusters observed in the Milky Way. The authors demonstrate that these clusters could contain black holes in binaries with stars known as blue stragglers, which may also be detectable with radial velocity techniques.Kremer and collaborators results suggest that globular clusters similar to NGC 3201 contain hundreds of invisible black holes waiting to be discovered, and they indicate some of the differences in cluster properties caused by hosting such a large population of black holes. We can hope that future observations and modeling will continue to illuminate the complicated relationship between globular clusters and the black holes that live in them.CitationKyle Kremer et al 2018 ApJL 855 L15. doi:10.3847/2041-8213/aab26c

Black to Black

DEFF Research Database (Denmark)

Langkjær, Michael Alexander

2012-01-01

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

Fermionic greybody factors in dilaton black holes

International Nuclear Information System (INIS)

Abedi, Jahed; Arfaei, Hessamaddin

2014-01-01

In this paper the question of the emission of fermions in the process of dilaton black hole evolution and its characteristics for different dilaton coupling constants α are studied. The main quantity of interest, the greybody factors, are calculated both numerically and in analytical approximation. The dependence of the rates of evaporation and behaviour on the dilaton coupling constant is analysed. Having calculated the greybody factors, we are able to address the question of the final fate of the dilaton black hole. For that we also need to perform dynamical treatment of the solution by considering the backreaction, which will show a crucial effect on the final result. We find a transition line in the (Q/M,α) plane that separates the two regimes for the fate of the black hole, decay regime and extremal regime. In the decay regime the black hole completely evaporates, while in the extremal regime the black hole approaches the extremal limit by radiation and becomes stable. (paper)

BLACK HOLE MASS ESTIMATES BASED ON C IV ARE CONSISTENT WITH THOSE BASED ON THE BALMER LINES

Energy Technology Data Exchange (ETDEWEB)

Assef, R. J.; Denney, K. D.; Kochanek, C. S.; Peterson, B. M.; Kozlowski, S.; Dietrich, M.; Grier, C. J.; Khan, R. [Department of Astronomy, The Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Ageorges, N.; Buschkamp, P.; Gemperlein, H.; Hofmann, R. [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstr., D-85748 Garching (Germany); Barrows, R. S. [Arkansas Center for Space and Planetary Sciences, University of Arkansas, Fayetteville, AR 72701 (United States); Falco, E.; Kilic, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Feiz, C.; Germeroth, A. [Landessternwarte, ZAH, Koenigstuhl 12, D-69117 Heidelberg (Germany); Juette, M.; Knierim, V. [Astron. Institut der Ruhr Univ. Bochum, Universitaetsstr. 150, D-44780 Bochum (Germany); Laun, W., E-mail: rjassef@astronomy.ohio-state.edu [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); and others

2011-12-01

Using a sample of high-redshift lensed quasars from the CASTLES project with observed-frame ultraviolet or optical and near-infrared spectra, we have searched for possible biases between supermassive black hole (BH) mass estimates based on the C IV, H{alpha}, and H{beta} broad emission lines. Our sample is based upon that of Greene, Peng, and Ludwig, expanded with new near-IR spectroscopic observations, consistently analyzed high signal-to-noise ratio (S/N) optical spectra, and consistent continuum luminosity estimates at 5100 A. We find that BH mass estimates based on the full width at half-maximum (FWHM) of C IV show a systematic offset with respect to those obtained from the line dispersion, {sigma}{sub l}, of the same emission line, but not with those obtained from the FWHM of H{alpha} and H{beta}. The magnitude of the offset depends on the treatment of the He II and Fe II emission blended with C IV, but there is little scatter for any fixed measurement prescription. While we otherwise find no systematic offsets between C IV and Balmer line mass estimates, we do find that the residuals between them are strongly correlated with the ratio of the UV and optical continuum luminosities. This means that much of the dispersion in previous comparisons of C IV and H{beta} BH mass estimates are due to the continuum luminosities rather than to any properties of the lines. Removing this dependency reduces the scatter between the UV- and optical-based BH mass estimates by a factor of approximately two, from roughly 0.35 to 0.18 dex. The dispersion is smallest when comparing the C IV {sigma}{sub l} mass estimate, after removing the offset from the FWHM estimates, and either Balmer line mass estimate. The correlation with the continuum slope is likely due to a combination of reddening, host contamination, and object-dependent SED shapes. When we add additional heterogeneous measurements from the literature, the results are unchanged. Moreover, in a trial observation of a

Discrete quantum spectrum of black holes

Energy Technology Data Exchange (ETDEWEB)

Lochan, Kinjalk, E-mail: kinjalk@iucaa.in; Chakraborty, Sumanta, E-mail: sumanta@iucaa.in

2016-04-10

The quantum genesis of Hawking radiation is a long-standing puzzle in black hole physics. Semi-classically one can argue that the spectrum of radiation emitted by a black hole look very much sparse unlike what is expected from a thermal object. It was demonstrated through a simple quantum model that a quantum black hole will retain a discrete profile, at least in the weak energy regime. However, it was suggested that this discreteness might be an artifact of the simplicity of eigen-spectrum of the model considered. Different quantum theories can, in principle, give rise to different complicated spectra and make the radiation from black hole dense enough in transition lines, to make them look continuous in profile. We show that such a hope from a geometry-quantized black hole is not realized as long as large enough black holes are dubbed with a classical mass area relation in any gravity theory ranging from GR, Lanczos–Lovelock to f(R) gravity. We show that the smallest frequency of emission from black hole in any quantum description, is bounded from below, to be of the order of its inverse mass. That leaves the emission with only two possibilities. It can either be non-thermal, or it can be thermal only with the temperature being much larger than 1/M.

Phase transitions and critical behaviour for charged black holes

International Nuclear Information System (INIS)

Carlip, S; Vaidya, S

2003-01-01

We investigate the thermodynamics of a four-dimensional charged black hole in a finite cavity in asymptotically flat and asymptotically de Sitter spaces. In each case, we find a Hawking-Page-like phase transition between a black hole and a thermal gas very much like the known transition in asymptotically anti-de Sitter space. For a 'supercooled' black hole - a thermodynamically unstable black hole below the critical temperature for the Hawking-Page phase transition - the phase diagram has a line of first-order phase transitions that terminates in a second-order point. For the asymptotically flat case, we calculate the critical exponents at the second-order phase transition and find that they exactly match the known results for a charged black hole in anti-de Sitter space. We find strong evidence for similar phase transitions for the de Sitter black hole as well. Thus many of the thermodynamic features of charged anti-de Sitter black holes do not really depend on asymptotically anti-de Sitter boundary conditions; the thermodynamics of charged black holes is surprisingly universal

Black Hole Kicks as New Gravitational Wave Observables.

Science.gov (United States)

Gerosa, Davide; Moore, Christopher J

2016-07-01

Generic black hole binaries radiate gravitational waves anisotropically, imparting a recoil, or kick, velocity to the merger remnant. If a component of the kick along the line of sight is present, gravitational waves emitted during the final orbits and merger will be gradually Doppler shifted as the kick builds up. We develop a simple prescription to capture this effect in existing waveform models, showing that future gravitational wave experiments will be able to perform direct measurements, not only of the black hole kick velocity, but also of its accumulation profile. In particular, the eLISA space mission will measure supermassive black hole kick velocities as low as ∼500  km s^{-1}, which are expected to be a common outcome of black hole binary coalescence following galaxy mergers. Black hole kicks thus constitute a promising new observable in the growing field of gravitational wave astronomy.

Reaction of Cauliflower Genotypes to Black Rot of Crucifers

Directory of Open Access Journals (Sweden)

Lincon Rafael da Silva

2015-06-01

Full Text Available This study aimed to evaluate six cauliflower genotypes regarding their resistance to black rot and their production performance. To do so, it was conducted two field experiments in Ipameri, Goiás, Brazil, in 2012 and 2013. It was used a randomized block design, with four replications (total of 24 plots. Each plot consisted of three planting lines 2.5 m long (six plants/line, spaced 1.0 m apart, for a total area of 7.5 m². Evaluations of black rot severity were performed at 45 days after transplanting, this is, 75 days after sowing (DAS, and yield evaluations at 90 to 105 DAS. The Verona 184 genotype was the most resistant to black rot, showing 1.87 and 2.25% of leaf area covered by black rot symptom (LACBRS in 2012 and 2013. However, it was not among the most productive materials. The yield of the genotypes varied between 15.14 and 25.83 t/ha in both years, Lisvera F1 (21.78 and 24.60 t/ha and Cindy (19.95 and 23.56 t/ha being the most productive. However, Lisvera F1 showed 6.37 and 9.37% of LACBRS and Cindy showed 14.25 and 14.87% of LACBRS in 2012 and 2013, being both considered as tolerant to black rot.

Black-hole galactic nuclei: a high-energy perspective

CERN Document Server

Boldt, E; Loewenstein, M

2002-01-01

The gravitational radiation signals to be anticipated from events involving black-hole galactic nuclei depend on the spin of the underlying object. To obtain evidence about the spin of Seyfert AGN black holes, we can rely on future ultra-high resolution spectral/spatial x-ray studies of iron K line fluorescence from the innermost regions of accreting matter. Normal galaxies present more of a challenge. To account for the highest energy cosmic rays, we propose that ultra-relativistic particle acceleration can occur near the event horizons of spun-up supermassive black-holes at the non-active nuclei of giant elliptical galaxies. This conjecture about the black hole spin associated with such nuclei is subject to verification via the characteristic TeV curvature radiation expected to be detected with upcoming gamma-ray observatories.

Superluminous Transients at AGN Centers from Interaction between Black Hole Disk Winds and Broad-line Region Clouds

Energy Technology Data Exchange (ETDEWEB)

Moriya, Takashi J.; Tanaka, Masaomi; Ohsuga, Ken [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Morokuma, Tomoki, E-mail: takashi.moriya@nao.ac.jp [Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)

2017-07-10

We propose that superluminous transients that appear at central regions of active galactic nuclei (AGNs) such as CSS100217:102913+404220 (CSS100217) and PS16dtm, which reach near- or super-Eddington luminosities of the central black holes, are powered by the interaction between accretion-disk winds and clouds in broad-line regions (BLRs) surrounding them. If the disk luminosity temporarily increases by, e.g., limit–cycle oscillations, leading to a powerful radiatively driven wind, strong shock waves propagate in the BLR. Because the dense clouds in the AGN BLRs typically have similar densities to those found in SNe IIn, strong radiative shocks emerge and efficiently convert the ejecta kinetic energy to radiation. As a result, transients similar to SNe IIn can be observed at AGN central regions. Since a typical black hole disk-wind velocity is ≃0.1 c , where c is the speed of light, the ejecta kinetic energy is expected to be ≃10{sup 52} erg when ≃1 M {sub ⊙} is ejected. This kinetic energy is transformed to radiation energy in a timescale for the wind to sweep up a similar mass to itself in the BLR, which is a few hundred days. Therefore, both luminosities (∼10{sup 44} erg s{sup −1}) and timescales (∼100 days) of the superluminous transients from AGN central regions match those expected in our interaction model. If CSS100217 and PS16dtm are related to the AGN activities triggered by limit–cycle oscillations, they become bright again in coming years or decades.

A near-infrared relationship for estimating black hole masses in active galactic nuclei

Science.gov (United States)

Landt, Hermine; Ward, Martin J.; Peterson, Bradley M.; Bentz, Misty C.; Elvis, Martin; Korista, Kirk T.; Karovska, Margarita

2013-06-01

Black hole masses for samples of active galactic nuclei (AGN) are currently estimated from single-epoch optical spectra using scaling relations anchored in reverberation mapping results. In particular, the two quantities needed for calculating black hole masses, namely the velocity and the radial distance of the orbiting gas are derived from the widths of the Balmer hydrogen broad emission lines and the optical continuum luminosity, respectively. We have recently presented a near-infrared (near-IR) relationship for estimating AGN black hole masses based on the widths of the Paschen hydrogen broad emission lines and the total 1 μm continuum luminosity. The near-IR offers several advantages over the optical: it suffers less from dust extinction, the AGN continuum is observed only weakly contaminated by the host galaxy and the strongest Paschen broad emission lines Paα and Paβ are unblended. Here, we improve the calibration of the near-IR black hole mass relationship by increasing the sample from 14 to 23 reverberation-mapped AGN using additional spectroscopy obtained with the Gemini Near-Infrared Spectrograph. The additional sample improves the number statistics in particular at the high-luminosity end.

Microscopic origin of black hole reentrant phase transitions

Science.gov (United States)

Zangeneh, M. Kord; Dehyadegari, A.; Sheykhi, A.; Mann, R. B.

2018-04-01

Understanding the microscopic behavior of the black hole ingredients has been one of the important challenges in black hole physics during the past decades. In order to shed some light on the microscopic structure of black holes, in this paper, we explore a recently observed phenomenon for black holes namely reentrant phase transition, by employing the Ruppeiner geometry. Interestingly enough, we observe two properties for the phase behavior of small black holes that leads to reentrant phase transition. They are correlated and they are of the interaction type. For the range of pressure in which the system underlies reentrant phase transition, it transits from the large black holes phase to the small one which possesses higher correlation than the other ranges of pressures. On the other hand, the type of interaction between small black holes near the large/small transition line differs for usual and reentrant phase transitions. Indeed, for the usual case, the dominant interaction is repulsive whereas for the reentrant case we encounter an attractive interaction. We show that in the reentrant phase transition case, the small black holes behave like a bosonic gas whereas in the usual phase transition case, they behave like a quantum anyon gas.

POX 52: A Dwarf Seyfert 1 Galaxy with an Intermediate-Mass Black Hole

Science.gov (United States)

Barth, Aaron J.; Ho, Luis C.; Rutledge, Robert E.; Sargent, Wallace L. W.

2004-05-01

We describe new optical images and spectra of POX 52, a dwarf galaxy with an active nucleus that was originally detected in the POX objective-prism survey. While POX 52 was originally thought to be a Seyfert 2 galaxy, the new data reveal an emission-line spectrum very similar to that of the dwarf Seyfert 1 galaxy NGC 4395, with broad components to the permitted line profiles, and we classify POX 52 as a Seyfert 1 galaxy. The host galaxy appears to be a dwarf elliptical, and its brightness profile is best fit by a Sérsic model with an index of 3.6+/-0.2 and a total magnitude of MV=-17.6. Applying mass-luminosity-line width scaling relations to estimate the black hole mass from the broad Hβ line width and nonstellar continuum luminosity, we find MBH~1.6×105Msolar. The stellar velocity dispersion in the host galaxy, measured from the Ca II λ8498, 8542 lines, is 36+/-5 km s-1, also suggestive of a black hole mass of order 105Msolar. Further searches for active nuclei in dwarf galaxies can provide unique constraints on the demographics of black holes in the mass range below 106Msolar.

Modular Electronics for Flash Memory Production

Science.gov (United States)

2011-12-28

DEFENSE TECHNICAL INFORMATION CENTER ImuM ktkUmlimäj DTICfhas determined on oc öf^H AJI that this Technical Document has the Distribution...the second harmonic (8I2/8V2), and a normalization to remove the scale of the measured current. The red dashed lines represent notable vibrational...superimposed as red dashed lines. The agreement between the two spectroscopies is conclusive that we have successfully put our OPE derivative into the gap

A SYSTEMATIC SEARCH FOR MASSIVE BLACK HOLE BINARIES IN THE SLOAN DIGITAL SKY SURVEY SPECTROSCOPIC SAMPLE

International Nuclear Information System (INIS)

Tsalmantza, P.; Decarli, R.; Hogg, David W.; Dotti, M.

2011-01-01

We present the results of a systematic search for massive black hole binaries in the Sloan Digital Sky Survey (SDSS) spectroscopic database. We focus on bound binaries, under the assumption that one of the black holes is active. In this framework, the broad lines associated with the accreting black hole are expected to show systematic velocity shifts with respect to the narrow lines, which trace the rest frame of the galaxy. For a sample of 54,586 quasars and 3929 galaxies at redshifts 0.1 < z < 1.5, we brute-force model each spectrum as a mixture of two quasars at two different redshifts. The spectral model is a data-driven dimensionality reduction of the SDSS quasar spectra based on a matrix factorization. We identified 32 objects with peculiar spectra. Nine of them can be interpreted as black hole binaries. This doubles the number of known black hole binary candidates. We also report on the discovery of a new class of extreme double-peaked emitters with exceptionally broad and faint Balmer lines. For all the interesting sources, we present detailed analysis of the spectra and discuss possible interpretations.

On-line applications of numerical models in the Black Sea GIS

Science.gov (United States)

Zhuk, E.; Khaliulin, A.; Zodiatis, G.; Nikolaidis, A.; Nikolaidis, M.; Stylianou, Stavros

2017-09-01

The Black Sea Geographical Information System (GIS) is developed based on cutting edge information technologies, and provides automated data processing and visualization on-line. Mapserver is used as a mapping service; the data are stored in MySQL DBMS; PHP and Python modules are utilized for data access, processing, and exchange. New numerical models can be incorporated in the GIS environment as individual software modules, compiled for a server-based operational system, providing interaction with the GIS. A common interface allows setting the input parameters; then the model performs the calculation of the output data in specifically predefined files and format. The calculation results are then passed to the GIS for visualization. Initially, a test scenario of integration of a numerical model into the GIS was performed, using software, developed to describe a two-dimensional tsunami propagation in variable basin depth, based on a linear long surface wave model which is legitimate for more than 5 m depth. Furthermore, the well established oil spill and trajectory 3-D model MEDSLIK (http://www.oceanography.ucy.ac.cy/medslik/) was integrated into the GIS with more advanced GIS functionality and capabilities. MEDSLIK is able to forecast and hind cast the trajectories of oil pollution and floating objects, by using meteo-ocean data and the state of oil spill. The MEDSLIK module interface allows a user to enter all the necessary oil spill parameters, i.e. date and time, rate of spill or spill volume, forecasting time, coordinates, oil spill type, currents, wind, and waves, as well as the specification of the output parameters. The entered data are passed on to MEDSLIK; then the oil pollution characteristics are calculated for pre-defined time steps. The results of the forecast or hind cast are then visualized upon a map.

Slowly balding black holes

International Nuclear Information System (INIS)

Lyutikov, Maxim; McKinney, Jonathan C.

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 the 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 =eΦ ∞ /(πc(ℎ/2π)), where Φ ∞ ≅2π 2 B NS R NS 3 /(P NS c) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. 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 balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.

Black holes at the centers of nearby dwarf galaxies

Energy Technology Data Exchange (ETDEWEB)

Moran, Edward C.; Shahinyan, Karlen; Sugarman, Hannah R.; Vélez, Darik O. [Astronomy Department, Wesleyan University, Middletown, CT 06459 (United States); Eracleous, Michael [Department of Astronomy and Astrophysics, and Institute for Gravitation and the Cosmos, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

2014-12-01

Using a distance-limited portion of the Sloan Digital Sky Survey (SDSS) Data Release 7, we have identified 28 active galactic nuclei (AGNs) in nearby (d⩽80 Mpc) low-mass, low-luminosity dwarf galaxies. The accreting objects at the galaxy centers are expected to be intermediate-mass black holes (IMBHs) with M{sub BH}⩽10{sup 6} M{sub ⊙}. The AGNs were selected using several optical emission-line diagnostics after careful modeling of the continuum present in the spectra. We have limited our survey to objects with spectral characteristics similar to those of Seyfert nuclei, excluding emission-line galaxies with ambiguous spectra that could be powered by stellar processes. Thus, as a set, the host galaxies in our sample are the least massive objects in the very local universe certain to contain central black holes. Our sample is dominated by narrow-line (type 2) AGNs, and it appears to have a much lower fraction of broad-line objects than that observed for luminous, optically selected Seyfert galaxies. Given our focus on the nearest objects included in the SDSS, our survey is more sensitive to low-luminosity emission than previous optical searches for AGNs in low-mass galaxies. The [O iii] λ5007 luminosities of the Seyfert nuclei in our sample have a median value of L{sub 5007}=2×10{sup 5} L{sub ⊙} and extend down to ∼10{sup 4} L{sub ⊙}. Using published data for broad-line IMBH candidates, we have derived an [O iii] bolometric correction of log(L{sub bol}/L{sub 5007})=3.0±0.3, which is significantly lower than values obtained for high-luminosity AGNs. Applying this correction to our sample, we obtain minimum black hole mass estimates that fall mainly in the 10{sup 3} M{sub ⊙}–10{sup 4} M{sub ⊙} range, which is roughly where the predicted mass functions for different black hole seed formation scenarios overlap the most. In the stellar mass range that includes the bulk of the AGN host galaxies in our sample, we derive a lower limit on the AGN fraction

Binary black holes: Spin dynamics and gravitational recoil

International Nuclear Information System (INIS)

Herrmann, Frank; Hinder, Ian; Shoemaker, Deirdre M.; Laguna, Pablo; Matzner, Richard A.

2007-01-01

We present a study of spinning black hole binaries focusing on the spin dynamics of the individual black holes as well as on the gravitational recoil acquired by the black hole produced by the merger. We consider two series of initial spin orientations away from the binary orbital plane. In one of the series, the spins are antialigned; for the second series, one of the spins points away from the binary along the line separating the black holes. We find a remarkable agreement between the spin dynamics predicted at 2nd post-Newtonian order and those from numerical relativity. For each configuration, we compute the kick of the final black hole. We use the kick estimates from the series with antialigned spins to fit the parameters in the Kidder kick formula, and verify that the recoil in the direction of the orbital angular momentum is ∝sinθ and on the orbital plane ∝cosθ, with θ the angle between the spin directions and the orbital angular momentum. We also find that the black hole spins can be well estimated by evaluating the isolated horizon spin on spheres of constant coordinate radius

Thermodynamics of hairy black holes in Lovelock gravity

Energy Technology Data Exchange (ETDEWEB)

Hennigar, Robie A. [Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1 (Canada); Tjoa, Erickson [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences,Nanyang Technological University, Singapore, 637371 (Singapore); Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1 (Canada); Mann, Robert B. [Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1 (Canada)

2017-02-14

We perform a thorough study of the thermodynamic properties of a class of Lovelock black holes with conformal scalar hair arising from coupling of a real scalar field to the dimensionally extended Euler densities. We study the linearized equations of motion of the theory and describe constraints under which the theory is free from ghosts/tachyons. We then consider, within the context of black hole chemistry, the thermodynamics of the hairy black holes in the Gauss-Bonnet and cubic Lovelock theories. We clarify the connection between isolated critical points and thermodynamic singularities, finding a one parameter family of these critical points which occur for well-defined thermodynamic parameters. We also report on a number of novel results, including ‘virtual triple points’ and the first example of a ‘λ-line’ — a line of second order phase transitions — in black hole thermodynamics.

Racial differences in sensitivity to behavioral integrity: attitudinal consequences, in-group effects, and "trickle down" among Black and non-Black employees.

Science.gov (United States)

Simons, Tony; Friedman, Ray; Liu, Leigh Anne; McLean Parks, Judi

2007-05-01

Recent research has suggested that employees are highly affected by perceptions of their managers' pattern of word-action consistency, which T. Simons (2002) called behavioral integrity (BI). The authors of the present study suggest that some employee racial groups may be more attentive to BI than others. They tested this notion using data from 1,944 employees working at 107 different hotels and found that Black employees rated their managers as demonstrating lower BI than did non-Black employees. Mediation analyses were consistent with the notion that these differences in perceived BI in turn account for cross-race differences in trust in management, interpersonal justice, commitment, satisfaction, and intent to stay. Results of hierarchical linear modeling were consistent with the idea that middle managers' perceptions of their senior managers' BI "trickle down" to affect line employee perceptions of the middle managers and that this trickle-down effect is stronger for Black employees. The authors interpret these results as indicative of heightened sensitivity to managers' BI on the part of Black employees. They also found a reverse in-group effect, in that Black employees were substantially more critical of Black managers than were non-Black employees. 2007 APA, all rights reserved

41 GHz and 10.6 GHz low threshold and low noise InAs/InP quantum dash two-section mode-locked lasers in L band

DEFF Research Database (Denmark)

Dontabactouny, M.; Piron, R.; Klaime, K.

2012-01-01

This paper reports recent results on InAs/InP quantum dash-based, two-section, passively mode-locked lasers pulsing at 41 GHz and 10.6 GHz and emitting at 1.59 mu m at 20 degrees C. The 41-GHz device (1 mm long) starts lasing at 25 mA under uniform injection and the 10.6 GHz (4 mm long) at 71 m...

Your Guide To Lowering Your Blood Pressure with DASH

Science.gov (United States)

... 4 tsp garlic, separated and peeled water red wine vinegar honey virgin olive oil black pepper 1. ... be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any ...

Cosmic censorship, black holes, and particle orbits

International Nuclear Information System (INIS)

Hiscock, W.A.

1979-01-01

One of the main reasons for believing in the cosmic censorship hypothesis is the disquieting nature of the alternative: the existence of naked singularities, and hence loss of predictability, the possibility of closed timelike lines and so forth. The consequences of assuming the cosmic hypothesis can also be somewhat strange and unexpected. In particular, Hawking's black hole area theorem is applied to the study of particle orbits near a Schwarzschild black hole. If the cosmic censorship hypothesis (and hence the area theorem) is true, then there exist stable near-circular orbits arbitrarily close to the horizon at r = 2M. (author)

A Be-type star with a black-hole companion.

Science.gov (United States)

Casares, J; Negueruela, I; Ribó, M; Ribas, I; Paredes, J M; Herrero, A; Simón-Díaz, S

2014-01-16

Stellar-mass black holes have all been discovered through X-ray emission, which arises from the accretion of gas from their binary companions (this gas is either stripped from low-mass stars or supplied as winds from massive ones). Binary evolution models also predict the existence of black holes accreting from the equatorial envelope of rapidly spinning Be-type stars (stars of the Be type are hot blue irregular variables showing characteristic spectral emission lines of hydrogen). Of the approximately 80 Be X-ray binaries known in the Galaxy, however, only pulsating neutron stars have been found as companions. A black hole was formally allowed as a solution for the companion to the Be star MWC 656 (ref. 5; also known as HD 215227), although that conclusion was based on a single radial velocity curve of the Be star, a mistaken spectral classification and rough estimates of the inclination angle. Here we report observations of an accretion disk line mirroring the orbit of MWC 656. This, together with an improved radial velocity curve of the Be star through fitting sharp Fe II profiles from the equatorial disk, and a refined Be classification (to that of a B1.5-B2 III star), indicates that a black hole of 3.8 to 6.9 solar masses orbits MWC 656, the candidate counterpart of the γ-ray source AGL J2241+4454 (refs 5, 6). The black hole is X-ray quiescent and fed by a radiatively inefficient accretion flow giving a luminosity less than 1.6 × 10(-7) times the Eddington luminosity. This implies that Be binaries with black-hole companions are difficult to detect in conventional X-ray surveys.

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

International Nuclear Information System (INIS)

Elbaz, David

2016-01-01

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

The Mass of the Black Hole in the Seyfert 1 Galaxy NGC 4593 from Reverberation Mapping

DEFF Research Database (Denmark)

Denney, Kelly D.; Bentz, Misty C.; Peterson, Bradley M.

2006-01-01

We present new observations leading to an improved black hole mass estimate for the Seyfert 1 galaxy NGC 4593 as part of a reverberation-mapping campaign conducted at the MDM Observatory. Cross-correlation analysis of the H_beta emission-line light curve with the optical continuum light curve...... reveals an emission-line time delay of 3.73 (+-0.75) days. By combining this time delay with the H_beta line width, we derive a central black hole mass of M_BH = 9.8(+-2.1)x10^6 M_sun, an improvement in precision of a factor of several over past results....

A rapidly spinning supermassive black hole at the centre of NGC 1365

DEFF Research Database (Denmark)

Risaliti, G.; Harrison, F. A.; Madsen, K. K.

2013-01-01

and relativistic effects near the black hole, the line shape being sensitive to its spin. Alternative models in which the distortions result from absorption by intervening structures provide an equally good description of the data, and there has been no general agreement on which is correct. Recent claims...... that the black hole (2 × 10(6) solar masses) at the centre of the galaxy NGC 1365 is rotating at close to its maximum possible speed rest on the assumption of relativistic reflection. Here we report X-ray observations of NGC 1365 that reveal the relativistic disk features through broadened Fe-line emission...... and an associated Compton scattering excess of 10-30 kiloelectronvolts. Using temporal and spectral analyses, we disentangle continuum changes due to time-variable absorption from reflection, which we find arises from a region within 2.5 gravitational radii of the rapidly spinning black hole. Absorption...

Visualizing, Approximating, and Understanding Black-Hole Binaries

Science.gov (United States)

Nichols, David A.

--7, we discuss using analytical approximations, such as post-Newtonian and black-hole-perturbation theories, to gain further understanding into how gravitational waves are generated by black-hole binaries. Chapter 5 presents a way of combining post-Newtonian and black-hole-perturbation theories---which we call the hybrid method---for head-on mergers of black holes. It was able to produce gravitational waveforms and gravitational recoils that agreed well with comparable results from numerical-relativity simulations. Chapter 6 discusses a development of the hybrid model to include a radiation-reaction force, which is better suited for studying inspiralling black-hole binaries. The gravitational waveform from the hybrid method for inspiralling mergers agreed qualitatively with that from numerical-relativity simulations; when applied to the superkick configuration, it gave a simplified picture of the formation of the large black-hole kick. Chapter 7 describes an approximate method of calculating the frequencies of the ringdown gravitational waveforms of rotating black holes (quasinormal modes). The method generalizes a geometric interpretation of black-hole quasinormal modes and explains a degeneracy in the spectrum of these modes. In Chapters 8--11, we describe a new way of visualizing spacetime curvature using tools called tidal tendexes and frame-drag vortexes. This relies upon a time-space split of spacetime, which allows one to break the vacuum Riemann curvature tensor into electric and magnetic parts (symmetric, trace-free tensors that have simple physical interpretations). The regions where the eigenvalues of these tensors are large form the tendexes and vortexes of a spacetime, and the integral curves of their eigenvectors are its tendex and vortex lines, for the electric and magnetic parts, respectively. Chapter 8 provides an overview of these visualization tools and presents initial results from numerical-relativity simulations. Chapter 9 uses topological

The mass of the black hole in the X-ray binary LMC X-1

Science.gov (United States)

Abubekerov, M. K.; Antokhina, E. A.; Gostev, N. Yu.; Cherepashchuk, A. M.; Shimansky, V. V.

2016-12-01

A dynamical estimate of the mass of the black hole in the LMC X-1 binary system is obtained in the framework of a Roche model for the optical star, based on fitting of the He I 4471 Å and He II 4200 Å absorption lines assuming LTE. The mass of the black hole derived from the radial-velocity curve for the He II 4200 Å line is m x = 10.55 M ⊙, close to the value found earlier based on a model with two point bodies [1].

The resistance response of sunflower genotypes to black stem disease under controlled conditions

Directory of Open Access Journals (Sweden)

Reza DARVISHZADEH

2010-09-01

Full Text Available Phoma black stem, caused by Phoma macdonaldii, is one of the most important diseases of sunflower in the world. The sources of resistance to Phoma black stem were investigated. A total of 184 genotypes, including some recombinant inbred lines (RILs, several M6 mutant lines obtained by gamma irradiation of seed of the genotype AS 613, and other genotypes from different countries, were evaluated against an aggressive French isolate (MP6 in controlled conditions. The study was carried out in a randomized complete block design with three replicates. Each replicate consisted of 10–12 seedlings. Twenty μL of spore suspension (106 pycnidiospores mL-1 were deposited on the intersection of the cotyledon petiole and the hypocotyl of sunflower plantlets at the two-leaf stage. The percentage of the area exhibiting disease symptoms was scored on the two cotyledon petioles of each of the plantlets three, five and seven days after inoculation. The disease progress rate (rd, as the slope of the regression line for disease severity against time, was also calculated. Analysis of variance detected significant differences among sunflower genotypes for disease severity 7 days after inoculation,as well as for the disease progress rate. A strong correlation (r=0.96, P<0.01 was found between disease severity 7 days after inoculation and the disease progress rate. The inbred lines F1250/03 (origin: Hungary, M5-54-1, M6-862-1 (mutant lines, SDR 18 (origin: USA and two wild Helianthus accessions, 1012 Nebraska and 211 Illinois, (wild type were highly resistant to Phoma black stem. These findings will assist breeders in choosing parent plants for breeding durable resistance to Phoma black stem.

The Crisis in Black and Black.

Science.gov (United States)

Hutchinson, Earl Ofari

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

Effect of temperature and ridge-width on the lasing characteristics of InAs/InP quantum-dash lasers: A thermal analysis view

Science.gov (United States)

Alkhazraji, E.; Khan, M. T. A.; Ragheb, A. M.; Fathallah, H.; Qureshi, K. K.; Alshebeili, S.; Khan, M. Z. M.

2018-01-01

We investigate the thermal characteristics of multi-stack chirped barrier thickness InAs/InGaAlAs/InP quantum-dash-in-a-well lasers of different ridge widths 2, 3, 4 and 15 μm. The effect of varying this geometrical parameter on the extracted thermal resistance and characteristic temperature, and their stability with temperature are examined. The results show an inverse relation of ridge-width with junction temperature with 2 μm device exhibiting the largest junction temperature buildup owing to an associated high thermal resistance of ∼45 °C/W. Under the light of this thermal analysis, lasing behavior of different ridge-width quantum-dash (Qdash) lasers with injection currents and operating temperatures, is investigated. Thermionic carrier escape and phonon-assisted tunneling are found to be the dominant carrier transport mechanisms resulting in wide thermal spread of carriers across the available transition states of the chirped active region. An emission coverage of ∼75 nm and 3 dB bandwidth of ∼55 nm is exhibited by the 2 μm device, thus possibly exploiting the inhomogeneous optical transitions to the fullest. Furthermore, successful external modulation of a single Qdash Fabry-Perot laser mode via injection locking is demonstrated with eye diagrams at bit rates of 2-12 Gbit/s incorporating various modulation schemes. These devices are being considered as potential light sources for future high-speed wavelength-division multiplexed optical communication systems.

Membrane viewpoint on black holes: Dynamical electromagnetic fields near the horizon

International Nuclear Information System (INIS)

Macdonald, D.A.; Suen, W.

1985-01-01

This paper is part of a series of papers with the aim of developing a complete self-consistent formalism for the treatment of electromagnetic and gravitational fields in the neighborhood of a black-hole horizon. In this membrane formalism, the horizon is treated as a closed two-dimensional membrane lying in a curved three-dimensional space, and endowed with familiar physical properties such as entropy and temperature, surface pressure and viscosity, and electrical conductivity, charge, and current. This paper develops the concept of the ''stretched horizon,'' which will be vital for both the electromagnetic and gravitational aspects of the formalism, and it presents several model problems illustrating the interaction of dynamical electromagnetic fields with stationary black-hole horizons: The field of a test charge in various states of motion outside the Schwarzschild horizon is analyzed in the near-horizon limit, where the spatial curvature may be ignored and the metric may be approximated by that of Rindler. This analysis elucidates the influence of the horizon on the shapes and motions of electric and magnetic field lines when external agents move the field lines in arbitrary manners. It also illustrates how the field lines interact with the horizon's charge and current to produce an exchange of energy and momentum between the external agent and the horizon. A numerical calculation of the dynamical relaxation of a magnetic field threading a Schwarzschild black hole is also presented, illustrating the ''cleaning'' of a complicated field structure by a black-hole horizon, and elucidating the constraints on the location of the stretched horizon

Ultra-luminous X-ray sources and intermediate-mass black holes

International Nuclear Information System (INIS)

Cseh, David

2012-01-01

More than ten years ago, the discovery of Ultra-luminous X-ray sources (ULXs) has opened up an entirely new field in astrophysics. Many ideas were developed to explain the nature of these sources, like their emission mechanism, mass, and origin, without any strong conclusions. Their discovery boosted the fields of X-ray binaries, accretion physics, stellar evolution, cosmology, black hole formation and growth, due to the concept of intermediate-mass black holes (IMBHs). Since their discovery is related to the domain of X-ray astrophysics, there have been very few studies made in other wavelengths. This thesis focuses on the multiwavelength nature of Ultra-luminous X-ray sources and intermediate-mass black holes from various aspects, which help to overcome some difficulties we face today. First, I investigated the accretion signatures of a putative intermediate-mass black hole in a particular globular cluster. To this purpose, I characterized the nature of the innermost X-ray sources in the cluster. Then I calculated an upper limit on the mass of the black hole by studying possible accretion efficiencies and rates based on the dedicated X-ray and radio observations. The accreting properties of the source was described with standard spherical accretion and in the context of inefficient accretion. Secondly, I attempted to dynamically measure the mass of the black hole in a particular ULX via optical spectroscopy. I discovered that a certain emission line has a broad component that markedly shifts in wavelength. I investigated the possibility whether this line originates in the accretion disk, and thus might trace the orbital motion of the binary system. I also characterized the parameters of the binary system, such as the mass function, possible orbital separation, the size of the line-emitting region, and an upper limit on the mass of the black hole. Then I studied the environment of a number of ULXs that are associated with large-scale optical and radio nebulae. I

YouDash3D: exploring stereoscopic 3D gaming for 3D movie theaters

Science.gov (United States)

Schild, Jonas; Seele, Sven; Masuch, Maic

2012-03-01

Along with the success of the digitally revived stereoscopic cinema, events beyond 3D movies become attractive for movie theater operators, i.e. interactive 3D games. In this paper, we present a case that explores possible challenges and solutions for interactive 3D games to be played by a movie theater audience. We analyze the setting and showcase current issues related to lighting and interaction. Our second focus is to provide gameplay mechanics that make special use of stereoscopy, especially depth-based game design. Based on these results, we present YouDash3D, a game prototype that explores public stereoscopic gameplay in a reduced kiosk setup. It features live 3D HD video stream of a professional stereo camera rig rendered in a real-time game scene. We use the effect to place the stereoscopic effigies of players into the digital game. The game showcases how stereoscopic vision can provide for a novel depth-based game mechanic. Projected trigger zones and distributed clusters of the audience video allow for easy adaptation to larger audiences and 3D movie theater gaming.

Observational Constraints on Quasar Black Hole Mass Distributions, Eddington Ratio Distributions, and Lifetimes

DEFF Research Database (Denmark)

Kelly, Brandon C.; Vestergaard, Marianne; Fan, X.

2010-01-01

I will present the black hole mass function (BHMF) of broad line quasars in the SDSS DR3. We employ a powerful Bayesian statistical technique that corrects for incompleteness and the statistical uncertainty in the mass estimates. We find evidence that the most massive black hole appeared as quasars...... earlier in the universe, and that most quasars are not radiating at or near the Eddington limit. I will also present constraints on the quasar lifetime and maximum black hole mass, derived from the mass functions....

Determining Central Black Hole Masses in Distant Active Galaxies

DEFF Research Database (Denmark)

Vestergaard, Marianne

2002-01-01

An empirical relationship, of particular interest for studies of high redshift active galactic nuclei (AGNs) and quasars, between the masses of their central black-holes and rest-frame ultraviolet (UV) parameters measured in single-epoch AGN spectra is presented. This relationship is calibrated...... black-hole demographics at high redshift as well as to statistically study the fundamental properties of AGNs. The broad line region size - luminosity relationship is key to the calibrations presented here. The fact that its intrinsic scatter is also the main source of uncertainty in the calibrations...

The Black Canyon of the Gunnison: Today and Yesterday

Science.gov (United States)

Hansen, Wallace R.

1965-01-01

Black Canyon in the immensity of its void, though its flaring walls lack the alarming verticality of the Black Canyon. Arizona's Grand Canyon of the Colorado is acknowledged as the greatest of them all; it is not as deep as Hells Canyon, but it is wider, longer, more rugged, and far more colorful. Its depth is two to three times that of the Black Canyon. Zion Canyon, Utah, combines depth, sheerness, serenity, and color in a chasm that ranges from capacious to extremely narrow. Its Narrows have a depth-to-width ratio unmatched by any other major American canyon. California's Yosemite Valley, in a setting of sylvan verdure, is unique among the gorges shown in profile in figure 1 in being the only glacial trough; its monolithic walls bear witness to the abrasive power of moving ice. Few cliffs in the world match the splendor of its El Capitan. Lodore Canyon, on the Green River in Dinosaur National Monument, Colorado, is best known, perhaps, for its noisy splashy rapids, first made famous by John Wesley Powell. Lodore Canyon also features towering cliffs of deep-red quartzite. Grand Canyon of the Yellowstone River, Wyoming, is noted for its great waterfalls, dashing river, and bright coloration. The Royal Gorge of the Arkansas River, Colorado, features the 'world's highest suspension bridge'. The profiles shown in figure 1 afford some basis for comparing one canyon with another. They cannot abstract in two dimensions the overall impression that each canyon makes. Color, vegetation, outcrop habit, vantage point, season of year, length of visit - even the roar of the river or lack thereof - all contribute to this highly personal effect. For a river of its size, the Gunnison has an unusually steep gradient through the Black Canyon. The river falls about 2,150 feet from the head of the canyon at Sapinero to the mouth at its junction with North Fork - a distance of about 50 miles and an average rate of fall of about 43 feet per mile. By comparison, the Green

THREE-DIMENSIONAL SIMULATIONS OF VERTICAL MAGNETIC FLUX IN THE IMMEDIATE VICINITY OF BLACK HOLES

International Nuclear Information System (INIS)

Punsly, Brian; Igumenshchev, Igor V.; Hirose, Shigenobu

2009-01-01

This article reports on three-dimensional MHD simulations of non-rotating and rapidly rotating black holes and the adjacent black hole accretion disk magnetospheres. A particular emphasis is placed on the vertical magnetic flux that is advected inward from large radii and threads the equatorial plane near the event horizon. In both cases of non-rotating and rotating black holes, the existence of a significant vertical magnetic field in this region is like a switch that creates powerful jets. There are many similarities in the vertical flux dynamics in these two cases in spite of the tremendous enhancement of azimuthal twisting of the field lines and enhancement of the jet power because of an 'ergospheric disk' in the Kerr metric. A three-dimensional approach is essential because two-dimensional axisymmetric flows are incapable of revealing the nature of the vertical flux near a black hole. Poloidal field lines from the ergospheric accretion region have been visualized in three dimensions and much of the article is devoted to a formal classification of the different manifestations of the vertical flux in the Kerr case.

Microlensing Signature of Binary Black Holes

Science.gov (United States)

Schnittman, Jeremy; Sahu, Kailash; Littenberg, Tyson

2012-01-01

We calculate the light curves of galactic bulge stars magnified via microlensing by stellar-mass binary black holes along the line-of-sight. We show the sensitivity to measuring various lens parameters for a range of survey cadences and photometric precision. Using public data from the OGLE collaboration, we identify two candidates for massive binary systems, and discuss implications for theories of star formation and binary evolution.

Super-Eddington Mechanical Power of an Accreting Black Hole in M83

Science.gov (United States)

Soria, R.; Long, K. S.; Blair, W. P.; Godfrey, L.; Kuntz, K. D.; Lenc, E.; Stockdale, C.; Winkler, P. F.

2014-01-01

Mass accretion onto black holes releases energy in the form of radiation and outflows. Although the radiative flux cannot substantially exceed the Eddington limit, at which the outgoing radiation pressure impedes the inflow of matter, it remains unclear whether the kinetic energy flux is bounded by this same limit. Here, we present the detection of a radio-optical structure, powered by outflows from a non-nuclear black hole. Its accretion disk properties indicate that this black hole is less than 100 solar masses. The optical-infrared line emission implies an average kinetic power of 3 × 10(exp 40) erg second(exp -1), higher than the Eddington luminosity of the black hole. These results demonstrate kinetic power exceeding the Eddington limit over a sustained period, which implies greater ability to influence the evolution of the black hole's environment.

How to Build a Supermassive Black Hole

Science.gov (United States)

Wanjek, Christopher

2003-01-01

NASA astronomer Kim Weaver has got that sinking feeling. You know, it's that unsettling notion you get when you sift through your X-ray data and, to your surprise, find mid-sized black holes sinking toward the center of a galaxy, where they merge with others to form a single supermassive black hole. Could such a thing be true? These would be the largest mergers since America On Line bought Time-Warner, and perhaps even more violent. The process would turn a starburst galaxy inside out, making it more like a quasar host galaxy. Using the Chandra X-Ray Observatory, Weaver saw a hint of this fantastic process in a relatively nearby starburst galaxy named NGC 253 in the constellation Sculptor. She noticed that starburst galaxies - those gems set aglow in a colorful life cycle of hyperactive star birth, death, and renewal - seem to have a higher concentration of mid-mass black holes compared to other galaxies.

Unshifted Metastable He I* Mini-broad Absorption Line System in the Narrow-line Type 1 Quasar SDSS J080248.18+551328.9

Science.gov (United States)

Ji, Tuo; Zhou, Hongyan; Jiang, Peng; Wang, Tinggui; Ge, Jian; Wang, Huiyuan; Komossa, S.; Hamann, Fred; Zuther, Jens; Liu, Wenjuan; Lu, Honglin; Zuo, Wenwen; Yang, Chenwei; Yuan, Weimin

2015-02-01

We report the identification of an unusual absorption-line system in the quasar SDSS J080248.18+551328.9 and present a detailed study of the system, incorporating follow-up optical and near-IR spectroscopy. A few tens of absorption lines are detected, including He I*, Fe II*, and Ni II*, which arise from metastable or excited levels, as well as resonant lines in Mg I, Mg II, Fe II, Mn II, and Ca II. All of the isolated absorption lines show the same profile of width Δv ~ 1500 km s-1 centered at a common redshift as that of the quasar emission lines, such as [O II], [S II], and hydrogen Paschen and Balmer series. With narrow Balmer lines, strong optical Fe II multiplets, and weak [O III] doublets, its emission-line spectrum is typical for that of a narrow-line Seyfert 1 galaxy (NLS1). We have derived reliable measurements of the gas-phase column densities of the absorbing ions/levels. Photoionization modeling indicates that the absorber has a density of n H ~ (1.0-2.5) × 105 cm-3 and a column density of N H ~ (1.0-3.2) × 1021 cm-2 and is located at R ~100-250 pc from the central supermassive black hole. The location of the absorber, the symmetric profile of the absorption lines, and the coincidence of the absorption- and emission-line centroid jointly suggest that the absorption gas originates from the host galaxy and is plausibly accelerated by stellar processes, such as stellar winds and/or supernova explosions. The implications for the detection of such a peculiar absorption-line system in an NLS1 are discussed in the context of coevolution between supermassive black hole growth and host galaxy buildup.

Investigating Supermassive Black Hole Spin at Different Redshift

Science.gov (United States)

Sinanan-Singh, Jasmine

2018-01-01

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

Toward Understanding the B[e] Phenomenon. VII. AS 386, a Single-lined Binary with a Candidate Black Hole Component

Science.gov (United States)

Khokhlov, S. A.; Miroshnichenko, A. S.; Zharikov, S. V.; Manset, N.; Arkharov, A. A.; Efimova, N.; Klimanov, S.; Larionov, V. M.; Kusakin, A. V.; Kokumbaeva, R. I.; Omarov, Ch. T.; Kuratov, K. S.; Kuratova, A. K.; Rudy, R. J.; Laag, E. A.; Crawford, K. B.; Swift, T. K.; Puetter, R. C.; Perry, R. B.; Chojnowski, S. D.; Agishev, A.; Caton, D. B.; Hawkins, R. L.; Smith, A. B.; Reichart, D. E.; Kouprianov, V. V.; Haislip, J. B.

2018-04-01

We report the results of spectroscopic and photometric observations of the emission-line object AS 386. For the first time we found that it exhibits the B[e] phenomenon and fits the definition of an FS CMa type object. The optical spectrum shows the presence of a B-type star with the following properties: T eff = 11,000 ± 500 K, log L/L ⊙ = 3.7 ± 0.3, a mass of 7 ± 1 M ⊙, and a distance D = 2.4 ± 0.3 kpc from the Sun. We detected regular radial velocity variations of both absorption and emission lines with the following orbital parameters: P orb =131.27 ± 0.09 days, semiamplitude K 1 = 51.7 ± 3.0 km s‑1, systemic radial velocity γ = ‑31.8 ± 2.6 km s‑1, and a mass function of f(m) = 1.9 ± 0.3 M ⊙. AS 386 exhibits irregular variations of the optical brightness (V = 10.92 ± 0.05 mag), while the near-IR brightness varies up to ∼0.3 mag following the spectroscopic period. We explain this behavior by a variable illumination of the dusty disk inner rim by the B-type component. Doppler tomography based on the orbital variations of emission-line profiles shows that the material is distributed near the B-type component and in a circumbinary disk. We conclude that the system has undergone a strong mass transfer that created the circumstellar material and increased the B-type component mass. The absence of any traces of a secondary component, whose mass should be ≥7 M ⊙, suggests that it is most likely a black hole.

Magnetic Origin of Black Hole Winds Across the Mass Scale

Science.gov (United States)

Fukumura, Keigo; Kazanas, Demosthenes; Shrader, Chris; Behar, Ehud; Tombesi, Francesco; Contopoulos, Ioannis

2017-01-01

Black hole accretion disks appear to produce invariably plasma outflows that result in blue-shifted absorption features in their spectra. The X-ray absorption-line properties of these outflows are quite diverse, ranging in velocity from non-relativistic (approx. 300 km/sec) to sub-relativistic (approx. 0.1c where c is the speed of light) and a similarly broad range in the ionization states of the wind plasma. We report here that semi-analytic, self-similar magnetohydrodynamic (MHD) wind models that have successfully accounted for the X-ray absorber properties of supermassive black holes, also fit well the high-resolution X-ray spectrum of the accreting stellar-mass black hole, GRO J1655-40. This provides an explicit theoretical argument of their MHD origin (aligned with earlier observational claims) and supports the notion of a universal magnetic structure of the observed winds across all known black hole sizes.

An Intermediate-Mass Black Hole in the Dwarf Seyfert 1 Galaxy POX 52

Science.gov (United States)

Barth, A.; Ho, L.; Sargent, W.

2004-06-01

We describe new observations of POX 52, a previously known but nearly forgotten example of a dwarf galaxy with an active nucleus. While POX 52 was originally thought to be a Seyfert 2 galaxy, the new data reveal an emission-line spectrum very similar to that of the dwarf Seyfert 1 galaxy NGC 4395, with clear broad components to the permitted line profiles. The host galaxy appears to be a dwarf elliptical; this is the only known case of a Seyfert nucleus in a galaxy of this type. Applying scaling relations to estimate the black hole mass from the broad Hβ linewidth and continuum luminosity, we find MBH ≈ 1.6×105 M⊙. The stellar velocity dispersion in the host galaxy is 36 km s-1, also suggestive of a black hole mass of order 105 M⊙. Further searches for AGNs in dwarf galaxies can provide crucial constraints on the demographics of black holes in the mass range below 106 M⊙.

CHIKE ANIAKOR: MASTER OF POETIC LINES

African Journals Online (AJOL)

PROF EKWUEME

2010-11-26

Nov 26, 2010 ... achieves a unified visual and poetic whole. In totality, the rendering exhibits the professional expertise in the artist by using lines to narrate social reality and communicate the artist's perspectives to the society. Plate 2: Templates of Memory. Medium: Broomstick and black link on paper. Size: 60 cm by 50 cm.

Estimating Black Hole Spin of PG 1322+659 with Observed Optical ...

Indian Academy of Sciences (India)

SED of PG 1322 + 659 from IR/optical to hard X-ray is plotted with dots. Three circle+cross points are near-IR JHK data. The solid black line represents X-ray spectrum fitted with a power law. The red line is the best-fitting result. 3. Results. PG 1322 +659 (z=0.1684) is a radio quiet quasar with X-ray continuum emission.

Radio-loudness in black hole transients: evidence for an inclination effect

Science.gov (United States)

Motta, S. E.; Casella, P.; Fender, R.

2018-06-01

Accreting stellar-mass black holes appear to populate two branches in a radio:X-ray luminosity plane. We have investigated the X-ray variability properties of a large number of black hole low-mass X-ray binaries, with the aim of unveiling the physical reasons underlying the radio-loud/radio-quiet nature of these sources, in the context of the known accretion-ejection connection. A reconsideration of the available radio and X-ray data from a sample of black hole X-ray binaries confirms that being radio-quiet is the more normal mode of behaviour for black hole binaries. In the light of this we chose to test, once more, the hypothesis that radio loudness could be a consequence of the inclination of the X-ray binary. We compared the slope of the `hard-line' (an approximately linear correlation between X-ray count rate and rms variability, visible in the hard states of active black holes), the orbital inclination, and the radio-nature of the sources of our sample. We found that high-inclination objects show steeper hard-lines than low-inclination objects, and tend to display a radio-quiet nature (with the only exception of V404 Cyg), as opposed to low-inclination objects, which appear to be radio-loud(er). While in need of further confirmation, our results suggest that - contrary to what has been believed for years - the radio-loud/quiet nature of black-hole low mass X-ray binaries might be an inclination effect, rather than an intrinsic source property. This would solve an important issue in the context of the inflow-outflow connection, thus providing significant constraints to the models for the launch of hard-state compact jets.

OPTICAL MONITORING OF THE BROAD-LINE RADIO GALAXY 3C 390.3

International Nuclear Information System (INIS)

Dietrich, Matthias; Peterson, Bradley M.; Grier, Catherine J.; Bentz, Misty C.; Eastman, Jason; Frank, Stephan; Gonzalez, Raymond; Marshall, Jennifer L.; DePoy, Darren L.; Prieto, Jose L.

2012-01-01

We have undertaken a new ground-based monitoring campaign on the broad-line radio galaxy 3C 390.3 to improve the measurement of the size of the broad emission-line region and to estimate the black hole mass. Optical spectra and g-band images were observed in late 2005 for three months using the 2.4 m telescope at MDM Observatory. Integrated emission-line flux variations were measured for the hydrogen Balmer lines Hα, Hβ, Hγ, and for the helium line He IIλ4686, as well as g-band fluxes and the optical active galactic nucleus (AGN) continuum at λ = 5100 Å. The g-band fluxes and the optical AGN continuum vary simultaneously within the uncertainties, τ cent (0.2 ± 1.1) days. We find that the emission-line variations are delayed with respect to the variable g-band continuum by τ(Hα) 56.3 +2.4 –6.6 days, τ(Hβ) = 44.3 +3.0 –3.3 days, τ(Hγ) = 58.1 +4.3 –6.1 days, and τ(He II 4686) = 22.3 +6.5 –3.8 days. The blue and red peaks in the double-peaked line profiles, as well as the blue and red outer profile wings, vary simultaneously within ±3 days. This provides strong support for gravitationally bound orbital motion of the dominant part of the line-emitting gas. Combining the time delay of the strong Balmer emission lines of Hα and Hβ and the separation of the blue and red peaks in the broad double-peaked profiles in their rms spectra, we determine M vir bh = 1.77 +0.29 –0.31 × 10 8 M ☉ and using σ line of the rms spectra M vir bh 2.60 +0.23 –0.31 × 10 8 M ☉ for the central black hole of 3C 390.3, respectively. Using the inclination angle of the line-emitting region which is measured from superluminal motion detected in the radio range, accretion disk models to fit the optical double-peaked emission-line profiles, and X-ray observations, the mass of the black hole amounts to M bh = 0.86 +0.19 –0.18 × 10 9 M ☉ (peak separation) and M bh 1.26 +0.21 –0.16 × 10 9 M ☉ (σ line ), respectively. This result is consistent with the black

Aerial surveys adjusted by ground surveys to estimate area occupied by black-tailed prairie dog colonies

Science.gov (United States)

Sidle, John G.; Augustine, David J.; Johnson, Douglas H.; Miller, Sterling D.; Cully, Jack F.; Reading, Richard P.

2012-01-01

Aerial surveys using line-intercept methods are one approach to estimate the extent of prairie dog colonies in a large geographic area. Although black-tailed prairie dogs (Cynomys ludovicianus) construct conspicuous mounds at burrow openings, aerial observers have difficulty discriminating between areas with burrows occupied by prairie dogs (colonies) versus areas of uninhabited burrows (uninhabited colony sites). Consequently, aerial line-intercept surveys may overestimate prairie dog colony extent unless adjusted by an on-the-ground inspection of a sample of intercepts. We compared aerial line-intercept surveys conducted over 2 National Grasslands in Colorado, USA, with independent ground-mapping of known black-tailed prairie dog colonies. Aerial line-intercepts adjusted by ground surveys using a single activity category adjustment overestimated colonies by ≥94% on the Comanche National Grassland and ≥58% on the Pawnee National Grassland. We present a ground-survey technique that involves 1) visiting on the ground a subset of aerial intercepts classified as occupied colonies plus a subset of intercepts classified as uninhabited colony sites, and 2) based on these ground observations, recording the proportion of each aerial intercept that intersects a colony and the proportion that intersects an uninhabited colony site. Where line-intercept techniques are applied to aerial surveys or remotely sensed imagery, this method can provide more accurate estimates of black-tailed prairie dog abundance and trends

THE AKARI 2.5-5.0 μm SPECTRAL ATLAS OF TYPE-1 ACTIVE GALACTIC NUCLEI: BLACK HOLE MASS ESTIMATOR, LINE RATIO, AND HOT DUST TEMPERATURE

Energy Technology Data Exchange (ETDEWEB)

Kim, Dohyeong; Im, Myungshin; Kim, Ji Hoon; Jun, Hyunsung David; Lee, Seong-Kook [Center for the Exploration of the Origin of the Universe (CEOU), Astronomy Program, Department of Physics and Astronomy, Seoul National University, Shillim-Dong, Kwanak-Gu, Seoul 151-742 (Korea, Republic of); Woo, Jong-Hak; Lee, Hyung Mok; Lee, Myung Gyoon [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Shillim-Dong, Kwanak-Gu, Seoul 151-742 (Korea, Republic of); Nakagawa, Takao; Matsuhara, Hideo; Wada, Takehiko; Takagi, Toshinobu [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-5210 (Japan); Oyabu, Shinki [Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602 (Japan); Ohyama, Youichi, E-mail: dohyeong@astro.snu.ac.kr, E-mail: mim@astro.snu.ac.kr [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China)

2015-01-01

We present 2.5-5.0 μm spectra of 83 nearby (0.002 < z < 0.48) and bright (K < 14 mag) type-1 active galactic nuclei (AGNs) taken with the Infrared Camera on board AKARI. The 2.5-5.0 μm spectral region contains emission lines such as Brβ (2.63 μm), Brα (4.05 μm), and polycyclic aromatic hydrocarbons (3.3 μm), which can be used for studying the black hole (BH) masses and star formation activity in the host galaxies of AGNs. The spectral region also suffers less dust extinction than in the ultra violet (UV) or optical wavelengths, which may provide an unobscured view of dusty AGNs. Our sample is selected from bright quasar surveys of Palomar-Green and SNUQSO, and AGNs with reverberation-mapped BH masses from Peterson et al. Using 11 AGNs with reliable detection of Brackett lines, we derive the Brackett-line-based BH mass estimators. We also find that the observed Brackett line ratios can be explained with the commonly adopted physical conditions of the broad line region. Moreover, we fit the hot and warm dust components of the dust torus by adding photometric data of SDSS, 2MASS, WISE, and ISO to the AKARI spectra, finding hot and warm dust temperatures of ∼1100 K and ∼220 K, respectively, rather than the commonly cited hot dust temperature of 1500 K.

Deriving the Regression Line with Algebra

Science.gov (United States)

Quintanilla, John A.

2017-01-01

Exploration with spreadsheets and reliance on previous skills can lead students to determine the line of best fit. To perform linear regression on a set of data, students in Algebra 2 (or, in principle, Algebra 1) do not have to settle for using the mysterious "black box" of their graphing calculators (or other classroom technologies).…

Evaluation of burst pressure prediction models for line pipes

Energy Technology Data Exchange (ETDEWEB)

Zhu, Xian-Kui, E-mail: zhux@battelle.org [Battelle Memorial Institute, 505 King Avenue, Columbus, OH 43201 (United States); Leis, Brian N. [Battelle Memorial Institute, 505 King Avenue, Columbus, OH 43201 (United States)

2012-01-15

Accurate prediction of burst pressure plays a central role in engineering design and integrity assessment of oil and gas pipelines. Theoretical and empirical solutions for such prediction are evaluated in this paper relative to a burst pressure database comprising more than 100 tests covering a variety of pipeline steel grades and pipe sizes. Solutions considered include three based on plasticity theory for the end-capped, thin-walled, defect-free line pipe subjected to internal pressure in terms of the Tresca, von Mises, and ZL (or Zhu-Leis) criteria, one based on a cylindrical instability stress (CIS) concept, and a large group of analytical and empirical models previously evaluated by Law and Bowie (International Journal of Pressure Vessels and Piping, 84, 2007: 487-492). It is found that these models can be categorized into either a Tresca-family or a von Mises-family of solutions, except for those due to Margetson and Zhu-Leis models. The viability of predictions is measured via statistical analyses in terms of a mean error and its standard deviation. Consistent with an independent parallel evaluation using another large database, the Zhu-Leis solution is found best for predicting burst pressure, including consideration of strain hardening effects, while the Tresca strength solutions including Barlow, Maximum shear stress, Turner, and the ASME boiler code provide reasonably good predictions for the class of line-pipe steels with intermediate strain hardening response. - Highlights: Black-Right-Pointing-Pointer This paper evaluates different burst pressure prediction models for line pipes. Black-Right-Pointing-Pointer The existing models are categorized into two major groups of Tresca and von Mises solutions. Black-Right-Pointing-Pointer Prediction quality of each model is assessed statistically using a large full-scale burst test database. Black-Right-Pointing-Pointer The Zhu-Leis solution is identified as the best predictive model.

Black Silicon Solar Cells with Black Ribbons

DEFF Research Database (Denmark)

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

2016-01-01

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

Further Rehabilitating CIV-based Black Hole Mass Estimates in Quasars

Science.gov (United States)

Brotherton, Michael S.; Runnoe, Jessie C.; Shang, Zhaohui; Varju, Melinda

2016-06-01

Virial black hole masses are routinely estimated for high-redshift quasars using the C IV lambda 1549 emission line using single-epoch spectra that provide a gas velocity and a continuum luminosity. Such masses are very uncertain, however, especially because C IV likely possesses a non-virial component that varies with the Eddington ratio. We have previously used the 1400 feature, a blend of S i IV and O IV] emission that does not suffer the problems of C IV, to rehabilitate C IV-based mases by providing a correction term. The C IV profile itself, however, provides enough information to correct the black hole masses and remove the effects of the non-virial component. We use Mg II-based black hole masses to calibrate and test a new C IV-based black hole mass formula using only C IV and continuum measurements superior to existing formulations, as well as to test for additional dependencies on luminosity.

Study of variation of tocochromanol and phytosterol contents in black and yellow seeds of Brassica napus L. doubled haploid populations.

Science.gov (United States)

Cegielska-Taras, Teresa; Nogala-Kałucka, Małgorzata; Szala, Laurencja; Siger, Aleksander

2016-01-01

In the study, an analysis of tocopherols, plastochomanol-8 and phytosterols was conducted using DH lines obtained from F1 hybrids of reciprocal crosses between yellow- and black-seeded lines. The biological material for the study consisted of two DH populations of winter oilseed rape obtained from F1 hybrids of reciprocal crosses between two DH lines: yellow- and black-seeded. Seed color was determined using a ColorFlex spectrophotometer. Fat content was determined via pulsed NMR. The levels of tocopherols, and plastochromanol-8 are analyzed using HPLC. Phytosterol contents and composition were determined by the GC method. The fat content of the black-seeded parental line was 49% and this was higher than that of the yellow-seeded parental line (44%). The fat content of DH line populations ranged from 44 to 51%. Total tocopherol content ranged from 460 to 602 mg/kg and the α-T/γ-T ratio was from 0.66 to 1.09. In parental lines H2-26 and Z-114 the total tocopherol content was 534 and 525 mg/kg, but the α-T/γ-T ratios were 0.81 and 1.21, respectively. The yellow-seeded parental line (Z-114) was characterized by a higher PC-8 content (81 mg/kg) than the H2-26 black-seeded parental line (58 mg/kg). The largest part of the total phytosterol content in seeds of both populations was β-sitosterol from 976 to 2148 mg/kg, followed by campasterol, from 636 to 1364 mg/kg, and brassicasterol from 375 to 678 mg/kg. The total tocopherol content ranged from 462 to 595 mg/kg (population HxZ) and from 460 to 602 mg/kg (population ZxH). Significantly positive correlations were observed between the seed color with α-T (r = 0.38, p phytosterol content were not noted. Considering the range of genetic variation among doubled haploids of two populations, selected DH lines may be good parents for further breeding programs focused on increasing the amount and improving the quality of oilseed rapeseed oil. However, further studies will also be made to determine the influence of the

The size of the narrow-line-emitting region in the Seyfert 1 galaxy NGC 5548 from emission-line variability

International Nuclear Information System (INIS)

Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S.; Bentz, M. C.; Vestergaard, M.; Kilerci-Eser, E.; G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" data-affiliation=" (Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" >Dalla Bontà, E.; G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" data-affiliation=" (Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" >Ciroi, S.

2013-01-01

The narrow [O III] λλ4959, 5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow-line-emitting region has a radius of only 1-3 pc and is denser (n e ∼ 10 5 cm –3 ) than previously supposed. The [O III] line width is consistent with virial motions at this radius given previous determinations of the black hole mass. Since the [O III] emission-line flux is usually assumed to be constant and is therefore used to calibrate spectroscopic monitoring data, the variability has ramifications for the long-term secular variations of continuum and emission-line fluxes, though it has no effect on shorter-term reverberation studies. We present corrected optical continuum and broad Hβ emission-line light curves for the period 1988-2008.

The size of the narrow-line-emitting region in the Seyfert 1 galaxy NGC 5548 from emission-line variability

Energy Technology Data Exchange (ETDEWEB)

Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S. [Department of Astronomy, The Ohio State University, 140 W 18th Avenue, Columbus, OH 43210 (United States); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, 25 Park Place, Suite 610, Atlanta, GA 30303 (United States); Vestergaard, M.; Kilerci-Eser, E. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Dalla Bontà, E.; Ciroi, S. [Dipartimento di Fisica e Astronomia " G. Galilei," Università di Padova, Vicolo dell' Osservatorio 3 I-35122, Padova (Italy)

2013-12-20

The narrow [O III] λλ4959, 5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow-line-emitting region has a radius of only 1-3 pc and is denser (n {sub e} ∼ 10{sup 5} cm{sup –3}) than previously supposed. The [O III] line width is consistent with virial motions at this radius given previous determinations of the black hole mass. Since the [O III] emission-line flux is usually assumed to be constant and is therefore used to calibrate spectroscopic monitoring data, the variability has ramifications for the long-term secular variations of continuum and emission-line fluxes, though it has no effect on shorter-term reverberation studies. We present corrected optical continuum and broad Hβ emission-line light curves for the period 1988-2008.

The fields of a naked singularity and a black hole in mutual equilibrium

Science.gov (United States)

Paolino, Armando; Pizzi, Marco

2008-01-01

Recently Alekseev and Belinski have presented a new exact solution of the Einstein-Maxwell equation which describes two Reissner-Nordstrom (RN) sources in reciprocal equilibrium (no struts nor strings) one source is a naked singularity, the other is a black hole. In this paper we use the Alekseev-Belinki solution in the special case in which the charge of the black hole is zero-therefore we have a naked singularity near a neutral black hole. We give the plots of the electric force lines in both the cases in which the naked singularity has a mass comparable with the black hole and in which it is much smaller. The analysis of this latter case confirm the goodness of the Hanni-Ruffini approximation.

Criteria for retrograde rotation of accreting black holes

Science.gov (United States)

Mikhailov, A. G.; Piotrovich, M. Yu; Gnedin, Yu N.; Natsvlishvili, T. M.; Buliga, S. D.

2018-06-01

Rotating supermassive black holes produce jets and their origin is connected to the magnetic field that is generated by accreting matter flow. There is a point of view that electromagnetic fields around rotating black holes are brought to the hole by accretion. In this situation the prograde accreting discs produce weaker large-scale black hole threading magnetic fields, implying weaker jets than in retrograde regimes. The basic goal of this paper is to find the best candidates for retrograde accreting systems in observed active galactic nuclei. We show that active galactic nuclei with low Eddington ratio are really the best candidates for retrograde systems. This conclusion is obtained for kinetically dominated Fanaroff-Riley class II radio galaxies, flat-spectrum radio-loud narrow-line Seyfert I galaxies and a number of nearby galaxies. Our conclusion is that the best candidates for retrograde systems are the noticeable population of active galactic nuclei in the Universe. This result corresponds to the conclusion that in the merging process the interaction of merging black holes with a retrograde circumbinary disc is considerably more effective for shrinking the binary system.

WEAK LINE QUASARS AT HIGH REDSHIFT: EXTREMELY HIGH ACCRETION RATES OR ANEMIC BROAD-LINE REGIONS?

International Nuclear Information System (INIS)

Shemmer, Ohad; Trakhtenbrot, Benny; Netzer, Hagai; Anderson, Scott F.; Brandt, W. N.; Schneider, Donald P.; Diamond-Stanic, Aleksandar M.; Fan Xiaohui; Lira, Paulina; Plotkin, Richard M.; Richards, Gordon T.; Strauss, Michael A.

2010-01-01

We present Gemini-North K-band spectra of two representative members of the class of high-redshift quasars with exceptionally weak rest-frame ultraviolet emission lines (WLQs), SDSS J114153.34+021924.3 at z = 3.55 and SDSS J123743.08+630144.9 at z = 3.49. In both sources, we detect an unusually weak broad Hβ line and place tight upper limits on the strengths of their [O III] lines. Virial, Hβ-based black hole mass determinations indicate normalized accretion rates of L/L Edd =0.4 for these sources, which is well within the range observed for typical quasars with similar luminosities and redshifts. We also present high-quality XMM-Newton imaging spectroscopy of SDSS J114153.34+021924.3 and find a hard-X-ray photon index of Γ = 1.91 +0.24 -0.22 , which supports the virial L/L Edd determination in this source. Our results suggest that the weakness of the broad emission lines in WLQs is not a consequence of an extreme continuum-emission source but instead due to abnormal broad emission line region properties.

An Extreme X-ray Disk Wind in the Black Hole Candidate IGR J17091-3624

Science.gov (United States)

King, A. L.; Miller, J. M.; Raymond, J.; Fabian, A. C.; Reynolds, C. S.; Kallman, T. R.; Maitra, D.; Cackett, E. M.; Rupen, M. P.

2012-01-01

Chandra spectroscopy of transient stellar-mass black holes in outburst has clearly revealed accretion disk winds in soft, disk-dominated states, in apparent anti-correlation with relativistic jets in low/hard states. These disk winds are observed to be highly ionized. dense. and to have typical velocities of approx 1000 km/s or less projected along our line of sight. Here. we present an analysis of two Chandra High Energy Transmission Grating spectra of the Galactic black hole candidate IGR J17091-3624 and contemporaneous EVLA radio observations. obtained in 2011. The second Chandra observation reveals an absorption line at 6.91+/-0.01 keV; associating this line with He-like Fe XXV requires a blue-shift of 9300(+500/-400) km/ s (0.03c. or the escape velocity at 1000 R(sub schw)). This projected outflow velocity is an order of magnitude higher than has previously been observed in stellar-mass black holes, and is broadly consistent with some of the fastest winds detected in active galactic nuclei. A potential feature at 7.32 keV, if due to Fe XXVI, would imply a velocity of approx 14600 km/s (0.05c), but this putative feature is marginal. Photoionization modeling suggests that the accretion disk wind in IGR J17091-3624 may originate within 43,300 Schwarzschild radii of the black hole, and may be expelling more gas than accretes. The contemporaneous EVLA observations strongly indicate that jet activity was indeed quenched at the time of our Chandra observations. We discuss the results in the context of disk winds, jets, and basic accretion disk physics in accreting black hole systems

Black holes

International Nuclear Information System (INIS)

Feast, M.W.

1981-01-01

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

Geometry of the 2+1 black hole

International Nuclear Information System (INIS)

Banados, M.; Henneaux, M.; Teitelboim, C.; Zanelli, J.

1993-01-01

The geometry of the spinning black holes of standard Einstein theory in 2+1 dimensions, with a negative cosmological constant, and without couplings to matter, is analyzed in detail. It is shown that the black hole arises from identifications of points of anti--de Sitter space by a discrete subgroup of SO(2,2). The generic black hole is a smooth manifold in the metric sense. The surface r=0 is not a curvature singularity but, rather, a singularity in the causal structure. Continuing past it would introduce closed timelike lines. However, simple examples show the regularity of the metric at r=0 to be unstable: couplings to matter bring in a curvature singularity there. Kruskal coordinates and Penrose diagrams are exhibited. Special attention is given to the limiting cases of (i) the spinless hole of zero mass, which differs from anti--de Sitter space and plays the role of the vacuum, and (ii) the spinning hole of maximal angular momentum. A thorough classification of the elements of the Lie algebra of SO(2,2) is given in an appendix

Irradiation of an Accretion Disc by a Jet: General Properties and Implications for Spin Measurements of Black Holes

Science.gov (United States)

T.Dauser; Garcia, J.; Wilms, J.; Boeck, M.; Brenneman, L. W.; Falanga, M.; Fukumura, Keigo; Reynolds, C. S.

2013-01-01

X-ray irradiation of the accretion disc leads to strong reflection features, which are then broadened and distorted by relativistic effects. We present a detailed, general relativistic approach to model this irradiation for different geometries of the primary X-ray source. These geometries include the standard point source on the rotational axis as well as more jet-like sources, which are radially elongated and accelerating. Incorporating this code in the RELLINE model for relativistic line emission, the line shape for any configuration can be predicted. We study how different irradiation geometries affect the determination of the spin of the black hole. Broad emission lines are produced only for compact irradiating sources situated close to the black hole. This is the only case where the black hole spin can be unambiguously determined. In all other cases the line shape is narrower, which could either be explained by a low spin or an elongated source. We conclude that for those cases and independent of the quality of the data, no unique solution for the spin exists and therefore only a lower limit of the spin value can be given

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...

The force-free magnetosphere of a rotating black hole

Directory of Open Access Journals (Sweden)

Contopoulos Ioannis

2013-12-01

Full Text Available We explore the analogy with pulsars and investigate the structure of the force-free magnetosphere around a Kerr black hole. We propose that the source of the black hole magnetic field is the Poynting-Robertson effect on the plasma electrons at the inner edge of the surrounding accretion disk, the so called Cosmic Battery. The magnetospheric solution is characterized by the distributions of the magnetic field angular velocity and the poloidal electric current. These are not arbitrary. They are determined self-consistently by requiring that magnetic field lines cross smoothly the two singular surfaces of the problem, the inner ‘light surface’ located inside the ergosphere, and the outer ‘light surface’ which is the generalization of the pulsar light cylinder. The black hole forms a relativistic jet only if it is surrounded by a thick disk and/or extended disk outflows.

OPTICAL MONITORING OF THE BROAD-LINE RADIO GALAXY 3C 390.3

Energy Technology Data Exchange (ETDEWEB)

Dietrich, Matthias; Peterson, Bradley M.; Grier, Catherine J.; Bentz, Misty C.; Eastman, Jason; Frank, Stephan; Gonzalez, Raymond; Marshall, Jennifer L.; DePoy, Darren L.; Prieto, Jose L., E-mail: dietrich@astronomy.ohio-state.edu [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States)

2012-09-20

We have undertaken a new ground-based monitoring campaign on the broad-line radio galaxy 3C 390.3 to improve the measurement of the size of the broad emission-line region and to estimate the black hole mass. Optical spectra and g-band images were observed in late 2005 for three months using the 2.4 m telescope at MDM Observatory. Integrated emission-line flux variations were measured for the hydrogen Balmer lines H{alpha}, H{beta}, H{gamma}, and for the helium line He II{lambda}4686, as well as g-band fluxes and the optical active galactic nucleus (AGN) continuum at {lambda} = 5100 A. The g-band fluxes and the optical AGN continuum vary simultaneously within the uncertainties, {tau}{sub cent} (0.2 {+-} 1.1) days. We find that the emission-line variations are delayed with respect to the variable g-band continuum by {tau}(H{alpha}) 56.3{sup +2.4}{sub -6.6} days, {tau}(H{beta}) = 44.3{sup +3.0}{sub -3.3} days, {tau}(H{gamma}) = 58.1{sup +4.3}{sub -6.1} days, and {tau}(He II 4686) = 22.3{sup +6.5}{sub -3.8} days. The blue and red peaks in the double-peaked line profiles, as well as the blue and red outer profile wings, vary simultaneously within {+-}3 days. This provides strong support for gravitationally bound orbital motion of the dominant part of the line-emitting gas. Combining the time delay of the strong Balmer emission lines of H{alpha} and H{beta} and the separation of the blue and red peaks in the broad double-peaked profiles in their rms spectra, we determine M {sup vir}{sub bh} = 1.77{sup +0.29}{sub -0.31} Multiplication-Sign 10{sup 8} M{sub Sun} and using {sigma}{sub line} of the rms spectra M {sup vir}{sub bh} 2.60{sup +0.23}{sub -0.31} Multiplication-Sign 10{sup 8} M{sub Sun} for the central black hole of 3C 390.3, respectively. Using the inclination angle of the line-emitting region which is measured from superluminal motion detected in the radio range, accretion disk models to fit the optical double-peaked emission-line profiles, and X-ray observations

Fenton process combined with coagulation for the treatment of black liquor from bioethanol wastewater

Science.gov (United States)

Muryanto, Muryanto; Hanifah, Ummu; Amriani, Feni; Ibadurrahman, Ahmad Faiz; Sari, Ajeng Arum

2017-11-01

High amounts of black liquor are generated from bioethanol production by using oil palm empty fruit bunches. The black liquor is waste from alkaline pretreatment, it contains high amount of an alkaline solution (NaOH). The black liquor wastewater was highly contaminated with organic materials, and quite toxic for aquatic ecosystems if discharged directly into waters. This study aimed to determine ability of Fenton process combined with coagulation to treat black liquor. The addition 5% of polyaluminium chloride (PAC) could decolorized black liquor, degraded lignin, and produced sludge 70.64%, 68.28%, and 2.76 gram, respectively. Decolorization of black liquor was in line with degradation of black liquor because lignin is the main compound in black liquor. SEM images after addition of PAC of 5% indicated fragmentation of structure. Fenton reagent consist of 0.7 M FeSO4+ 3M H2O2 has able to decolorize black liquor, degrade lignin, and produce sludge 51.67% and 25.44%, and 0.44 gram, respectively. It was concluded that black liquor wastewater from bioethanol can be treated by using Fenton process combined with coagulation. However, these methods still need improvement to obtain the higher degradation rate, and coagulation sludge needs further consideration.

Black rings

International Nuclear Information System (INIS)

Emparan, Roberto; Reall, Harvey S

2006-01-01

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

The trochlear cleft: the ''black line'' of the trochlear trough

Energy Technology Data Exchange (ETDEWEB)

Wissman, Robert D.; Nepute, Joshua; Fischer, Nathaniel von; Radhakrishnan, Rupa; Hendry, Daniel [University of Cincinnati Medical Center, Department of Radiology, Cincinnati, OH (United States); Ingalls, Jerrell [Desert Radiologists, Las Vegas, NV (United States); Kenter, Keith [University of Cincinnati Medical Center, Department of Orthopaedic Surgery, Cincinnati, OH (United States)

2012-09-15

The ''cartilage black line sign'' is a recently described T2 dark cartilage lesion that we have identified appearing as a cleft in the trochlear trough. The purpose of our study was to define the MR imaging characteristics of a trochlear cleft, determine its incidence, and correlate the MR findings with arthroscopy. A total of 1,300 consecutive MR examinations of the knee were retrospectively reviewed by consensus of two fellowship-trained musculoskeletal radiologists. The MR imaging characteristics and location of a trochlear cleft were determined. Imaging results were compared to arthroscopy when available. Patient age and gender were compared to 25 randomly selected control patients without trochlear clefts. A total of 25 (1.9%) individuals (11 females and 14 males; age range 19-45 years; mean age 28 years) were diagnosed with a trochlear cleft. The control group consisted of 11 females and 14 males; age range 19-83 years; mean age 46 years. Mean cleft length was 7 mm (range 6-12 mm); cleft location was consistently in the lower trochlear trough. No full-thickness cartilage defects were identified in the eight individuals in whom arthroscopic correlation was available. A grade 2 cartilage lesion was identified in a single individual; another progressed from grade 0 to a full-thickness trochlear lesion over an 8-month interval. Eight individuals were athletes. No significant difference in gender was noted between the two groups, however, the study group was significantly younger p < 0.0001. A trochlear cleft is a rare finding in young active individuals. It most likely indicates an incomplete cartilage fissure which may rarely progress to a full-thickness defect. (orig.)

"Black Like Me": Reframing Blackness for Decolonial Politics

Science.gov (United States)

Dei, George J. Sefa

2018-01-01

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

Long-Term Monitoring of the Broad-Line Region Properties in a Selected Sample of AGN

Energy Technology Data Exchange (ETDEWEB)

Ilić, Dragana [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Shapovalova, Alla I. [Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz (Russian Federation); Popović, Luka Č. [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Astronomical Observatory, Belgrade (Serbia); Chavushyan, Vahram [Instituto Nacional de Astrofísica, Óptica y Electrónica, Puebla (Mexico); Burenkov, Alexander N. [Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz (Russian Federation); Kollatschny, Wolfram [Institut fuer Astrophysik, Universitaet Goettingen, Göttingen (Germany); Kovačević, Andjelka [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Marčeta-Mandić, Sladjana [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Astronomical Observatory, Belgrade (Serbia); Rakić, Nemanja [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Belgrade (Serbia); Faculty of Science, University of Banjaluka, Banjaluka, Republic of Srpska (Bosnia and Herzegovina); La Mura, Giovanni; Rafanelli, Piero, E-mail: dilic@math.rs [Department of Physics and Astronomy, University of Padova, Padova (Italy)

2017-09-14

We present the results of the long-term optical monitoring campaign of active galactic nuclei (AGN) coordinated by the Special Astrophysical Observatory of the Russian Academy of Science. This campaign has produced a remarkable set of optical spectra, since we have monitored for several decades different types of broad-line (type 1) AGN, from a Seyfert 1, double-peaked line, radio loud and radio quiet AGN, to a supermassive binary black hole candidate. Our analysis of the properties of the broad line region (BLR) of these objects is based on the variability of the broad emission lines. We hereby give a comparative review of the variability properties of the broad emission lines and the BLR of seven different type 1 AGNs, emphasizing some important results, such as the variability rate, the BLR geometry, and the presence of the intrinsic Baldwin effect. We are discussing the difference and similarity in the continuum and emission line variability, focusing on what is the impact of our results to the supermassive black hole mass determination from the BLR properties.

Long-Term Monitoring of the Broad-Line Region Properties in a Selected Sample of AGN

Directory of Open Access Journals (Sweden)

Dragana Ilić

2017-09-01

Full Text Available We present the results of the long-term optical monitoring campaign of active galactic nuclei (AGN coordinated by the Special Astrophysical Observatory of the Russian Academy of Science. This campaign has produced a remarkable set of optical spectra, since we have monitored for several decades different types of broad-line (type 1 AGN, from a Seyfert 1, double-peaked line, radio loud and radio quiet AGN, to a supermassive binary black hole candidate. Our analysis of the properties of the broad line region (BLR of these objects is based on the variability of the broad emission lines. We hereby give a comparative review of the variability properties of the broad emission lines and the BLR of seven different type 1 AGNs, emphasizing some important results, such as the variability rate, the BLR geometry, and the presence of the intrinsic Baldwin effect. We are discussing the difference and similarity in the continuum and emission line variability, focusing on what is the impact of our results to the supermassive black hole mass determination from the BLR properties.

COMMENT ON THE BLACK HOLE RECOIL CANDIDATE QUASAR SDSS J092712.65+294344.0

International Nuclear Information System (INIS)

Shields, G. A.; Bonning, E. W.; Salviander, S.

2009-01-01

The Sloan Digital Sky Survey (SDSS) quasar J092712.65+294344.0 has been proposed as a candidate for a supermassive black hole (∼10 8.8 M sun ) ejected at high speed from the host galactic nucleus by gravitational radiation recoil, or alternatively for a supermassive black hole binary. This is based on a blueshift of 2650 km s -1 of the broad emission lines ('b-system') relative to the narrow emission lines ('r-system') presumed to reflect the galaxy velocity. New observations with the Hobby-Eberly Telescope (HET) confirm the essential features of the spectrum. We note a third redshift system, characterized by weak, narrow emission lines of [O III] and [O II] at an intermediate velocity 900 km s -1 redward of the broad-line velocity ('i-system'). A composite spectrum of SDSS QSOs similar to J0927+2943 illustrates the feasibility of detecting the calcium K absorption line in spectra of sufficient quality. The i-system may represent the QSO host galaxy or a companion. Photoionization requires the black hole to be ∼3 kpc from the r-system emitting gas, implying that we are observing the system only 10 6 yr after the recoil event and contributing to the low probability of observing such a system. The HET observations give an upper limit of 10 km s -1 per year on the rate of change of the velocity difference between the r- and b-systems, constraining the orbital phase in the binary model. These considerations and the presence of a cluster of galaxies apparently containing J0927+2943 favor the idea that this system represents a superposition of two active galactic nuclei.

Improved Materials for Use as Components in Kraft Black Liquor Recovery Boilers; TOPICAL

International Nuclear Information System (INIS)

Keiser, J.R.

2001-01-01

This Cooperative Research and Development Agreement (CRADA) was undertaken to evaluate current and improved materials and materials processing conditions for use as components in kraft black liquor recovery boilers and other unit processes. The main areas addressed were: (1) Improved Black Liquor Nozzles, (2) Weld Overlay of Composite Floor Tubes, and (3) Materials for Lime Kilns. Iron aluminide was evaluated as an alternate material for the nozzles used to inject an aqueous solution known as black liquor into recovery boilers as well for the uncooled lining in the ports used for the nozzles. Although iron aluminide is known to have much better sulfidation resistance in gases than low alloy and stainless steels, it did not perform adequately in the environment where it came into contact with molten carbonate, sulfide and sulfate salts. Weld overlaying carbon steel tubes with a layer of stainless weld metal was a proposed method of extending the life of recovery boiler floor tubes that have experienced considerable fireside corrosion. After exposure under service conditions, sections of weld overlaid floor tubes were removed from a boiler floor and examined metallographically. Examination results indicated satisfactory performance of the tubes. Refractory-lined lime kilns are a critical component of the recovery process in kraft pulp mills, and the integrity of the lining is essential to the successful operation of the kiln. A modeling study was performed to determine the cause of, and possible solutions for, the repeated loss of the refractory lining from the cooled end of a particular kiln. The evaluation showed that the temperature, the brick shape and the coefficient of friction between the bricks were the most important parameters influencing the behavior of the refractory lining

Efficient topology optimization in MATLAB using 88 lines of code

DEFF Research Database (Denmark)

Andreassen, Erik; Clausen, Anders; Schevenels, Mattias

2011-01-01

The paper presents an efficient 88 line MATLAB code for topology optimization. It has been developed using the 99 line code presented by Sigmund (Struct Multidisc Optim 21(2):120–127, 2001) as a starting point. The original code has been extended by a density filter, and a considerable improvemen...... of the basic code to include recent PDE-based and black-and-white projection filtering methods. The complete 88 line code is included as an appendix and can be downloaded from the web site www.topopt.dtu.dk....

Jets, black holes and disks in blazars

Directory of Open Access Journals (Sweden)

Ghisellini Gabriele

2013-12-01

Full Text Available The Fermi and Swift satellites, together with ground based Cherenkov telescopes, has greatly improved our knowledge of blazars, namely Flat Spectrum Radio Quasars and BL Lac objects, since all but the most powerful emit most of their electro–magnetic output at γ–ray energies, while the very powerful blazars emit mostly in the hard X–ray region of the spectrum. Often they show coordinated variability at different frequencies, suggesting that in these cases the same population of electrons is at work, in a single zone of the jet. The location of this region along the jet is a matter of debate. The jet power correlates with the mass accretion rate, with jets existing at all values of disk luminosities, measured in Eddington units, sampled so far. The most powerful blazars show clear evidence of the emission from their disks, and this has revived methods of finding the black hole mass and accretion rate by modelling a disk spectrum to the data. Being so luminous, blazars can be detected also at very high redshift, and therefore are a useful tool to explore the far universe. One interesting line of research concerns how heavy are their black holes at high redshifts. If we associate the presence of a relativistic jets with a fastly spinning black hole, then we naively expect that the accretion efficiency is larger than for non–spinning holes. As a consequence, the black hole mass in jetted systems should grow at a slower rate. In turn, this would imply that, at high redshifts, the heaviest black holes should be in radio–quiet quasars. We instead have evidences of the opposite, challenging our simple ideas of how a black hole grows.

Stabilization of self-mode-locked quantum dash lasers by symmetric dual-loop optical feedback

Science.gov (United States)

Asghar, Haroon; Wei, Wei; Kumar, Pramod; Sooudi, Ehsan; McInerney, John. G.

2018-02-01

We report experimental studies of the influence of symmetric dual-loop optical feedback on the RF linewidth and timing jitter of self-mode-locked two-section quantum dash lasers emitting at 1550 nm. Various feedback schemes were investigated and optimum levels determined for narrowest RF linewidth and low timing jitter, for single-loop and symmetric dual-loop feedback. Two symmetric dual-loop configurations, with balanced and unbalanced feedback ratios, were studied. We demonstrate that unbalanced symmetric dual loop feedback, with the inner cavity resonant and fine delay tuning of the outer loop, gives narrowest RF linewidth and reduced timing jitter over a wide range of delay, unlike single and balanced symmetric dual-loop configurations. This configuration with feedback lengths 80 and 140 m narrows the RF linewidth by 4-67x and 10-100x, respectively, across the widest delay range, compared to free-running. For symmetric dual-loop feedback, the influence of different power split ratios through the feedback loops was determined. Our results show that symmetric dual-loop feedback is markedly more effective than single-loop feedback in reducing RF linewidth and timing jitter, and is much less sensitive to delay phase, making this technique ideal for applications where robustness and alignment tolerance are essential.

Black Alcoholism.

Science.gov (United States)

Watts, Thomas D.; Wright, Roosevelt

1988-01-01

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

Equal Area Laws and Latent Heat for d-Dimensional RN-AdS Black Hole

International Nuclear Information System (INIS)

Ma, Meng-Sen; Zhao, Ren; Zhang, Li-Chun; Zhao, Hui-Hua

2014-01-01

We study the equal area laws of d-dimensional RN-AdS black hole. We choose two kinds of phase diagrams, P-V and T-S. We employ the equal area laws to find an isobar which is the real two-phase coexistence line. Our calculation is much simpler to derive the critical value of the thermodynamic quantities. According to the thermodynamic quantities, we also study the latent heat of the black hole

Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes

Energy Technology Data Exchange (ETDEWEB)

Chartas, G.; Zalesky, L. [Department of Physics and Astronomy, College of Charleston, Charleston, SC 29424 (United States); Krawczynski, H. [Physics Department and McDonnell Center for the Space Sciences, Washington University in St. Louis, 1 Brookings Drive, CB 1105, St. Louis, MO 63130 (United States); Kochanek, C. S. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Dai, X. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States); Morgan, C. W.; Mosquera, A., E-mail: chartasg@cofc.edu [Physics Department, United States Naval Academy, Annapolis, MD 21403 (United States)

2017-03-01

We present a promising new technique, the g -distribution method, for measuring the inclination angle ( i ), the innermost stable circular orbit (ISCO), and the spin of a supermassive black hole. The g -distribution method uses measurements of the energy shifts in the relativistic iron line emitted by the accretion disk of a supermassive black hole due to microlensing by stars in a foreground galaxy relative to the g -distribution shifts predicted from microlensing caustic calculations. We apply the method to the gravitationally lensed quasars RX J1131–1231 ( z {sub s} = 0.658, z {sub l} = 0.295), QJ 0158–4325 ( z {sub s} = 1.294, z {sub l} = 0.317), and SDSS 1004+4112 ( z {sub s} = 1.734, z {sub l} = 0.68). For RX J1131−1231, our initial results indicate that r {sub ISCO} ≲ 8.5 gravitational radii ( r {sub g}) and i ≳ 55° (99% confidence level). We detect two shifted Fe lines in several observations, as predicted in our numerical simulations of caustic crossings. The current Δ E distribution of RX J1131–1231 is sparsely sampled, but further X-ray monitoring of RX J1131–1231 and other lensed quasars will provide improved constraints on the inclination angles, ISCO radii, and spins of the black holes of distant quasars.

X-Ray Spectra from MHD Simulations of Accreting Black Holes

Science.gov (United States)

Schnittman, Jeremy D.; Krolik, Julian H.; Noble, Scott C.

2012-01-01

We present the results of a new global radiation transport code coupled to a general relativistic magneto-hydrodynamic simulation of an accreting, nonrotating black hole. For the first time, we are able to explain from first principles in a self-consistent way the X-ray spectra observed from stellar-mass black holes, including a thermal peak, Compton reflection hump, power-law tail, and broad iron line. Varying only the mass accretion rate, we are able to reproduce the low/hard, steep power-law, and thermal-dominant states seen in most galactic black hole sources. The temperature in the corona is T(sub e) 10 keV in a boundary layer near the disk and rises smoothly to T(sub e) greater than or approximately 100 keV in low-density regions far above the disk. Even as the disk's reflection edge varies from the horizon out to approximately equal to 6M as the accretion rate decreases, we find that the shape of the Fe Ka line is remarkably constant. This is because photons emitted from the plunging region are strongly beamed into the horizon and never reach the observer. We have also carried out a basic timing analysis of the spectra and find that the fractional variability increases with photon energy and viewer inclination angle, consistent with the coronal hot spot model for X-ray fluctuations.

CHAOTIC MOTION OF CHARGED PARTICLES IN AN ELECTROMAGNETIC FIELD SURROUNDING A ROTATING BLACK HOLE

International Nuclear Information System (INIS)

Takahashi, Masaaki; Koyama, Hiroko

2009-01-01

The observational data from some black hole candidates suggest the importance of electromagnetic fields in the vicinity of a black hole. Highly magnetized disk accretion may play an importance rule, and large-scale magnetic field may be formed above the disk surface. Then, we expect that the nature of the black hole spacetime would be revealed by magnetic phenomena near the black hole. We will start investigating the motion of a charged test particle which depends on the initial parameter setting in the black hole dipole magnetic field, which is a test field on the Kerr spacetime. Particularly, we study the spin effects of a rotating black hole on the motion of the charged test particle trapped in magnetic field lines. We make detailed analysis for the particle's trajectories by using the Poincare map method, and show the chaotic properties that depend on the black hole spin. We find that the dragging effects of the spacetime by a rotating black hole weaken the chaotic properties and generate regular trajectories for some sets of initial parameters, while the chaotic properties dominate on the trajectories for slowly rotating black hole cases. The dragging effects can generate the fourth adiabatic invariant on the particle motion approximately.

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Indian Academy of Sciences (India)

2012; Eracleous et al. 2012; Popovic 2012; Gaskell & Goosmann 2013; Gaskell 2014; Goosmann et al. ..... Full lines correspond to (b, B) = (0.45,0.55), while lower (upper) dashed lines are minimums ..... 2014, ApJ, 788, 159. Kun, É., Karouzos ...

Lunar and Planetary Science XXXV: Astrobiology Stew: Pinch of Microbes, Smidgen of UV, Touch of Organics, and Dash of Meteorites

Science.gov (United States)

2004-01-01

The session Astrobiology Stew: Pinch of Microbes, Smidgen of UV, Touch of Organics, and Dash of Meteorites includes the following topics: 1) Investigating the Impact of UV Radiation on High-Altitude Shallow Lake Habitats, Life Diversity, and Life Survival Strategies: Clues for Mars' Past Habitability Potential? 2) An Analysis of Potential Photosynthetic Life on Mars; 3) Radiation Inactivation of Bacterial spores on Mars; 4) Hydrophobic Surfaces of Spacecraft Components Enhance the Aggregation of Microorganisms and May Lead to Higher Survival Rates of Bacteria on Mars Landers; 5) Optical Detection of Organic Chemical Biosignatures at Hydrothermal Vents; 6) Signs of Life in Meridiani Planum-What Might Opportunity See (or Miss)? 7) Isolation of PUrines and Pyrimidines from the Murchison Meteorite Using Sublimation; and 8) Relative Amino Acid Composition of CM1 Carbonaceous Chondrites.

Can double-peaked lines indicate merging effects in AGNs?

Directory of Open Access Journals (Sweden)

Popović L.Č.

2000-01-01

Full Text Available The influence of merging effects in the central part of an Active Galactic Nucleus (AGN on the emission spectral line shapes are discussed. We present a model of close binary Broad Line Region. The numerical experiments show that the merging effects can explain double peaked lines. The merging effects may also be present in the center of AGNs, although they emit slightly asymmetric as well as symmetric and relatively stable (in profile shape spectral lines. Depending on the black hole masses and their orbit elements such model may explain some of the line profile shapes observed in AGNs. This work shows that if one is looking for the merging effects in the central region as well as in the wide field structure of AGNs, he should first pay attention to objects which have double peaked lines.

The mass of the central black hole in the nearby Seyfert galaxy NGC 5273

Energy Technology Data Exchange (ETDEWEB)

Bentz, Misty C.; Horenstein, Daniel; Bazhaw, Craig; Manne-Nicholas, Emily R.; Ou-Yang, Benjamin J.; Anderson, Matthew; Jones, Jeremy; Norris, Ryan P.; Parks, J. Robert; Saylor, Dicy; Teems, Katherine G.; Turner, Clay, E-mail: bentz@astro.gsu.edu [Department of Physics and Astronomy, Georgia State University, 25 Park Place, Suite 600, Atlanta, GA 30303 (United States)

2014-11-20

We present the results of a reverberation-mapping program targeting NGC 5273, a nearby early-type galaxy with a broad-lined active galactic nucleus (AGN). Over the course of the monitoring program, NGC 5273 showed strong variability that allowed us to measure time delays in the responses of the broad optical recombination lines to changes in the continuum flux. A weighted average of these measurements results in a black hole mass determination of M {sub BH} = (4.7 ± 1.6) × 10{sup 6} M {sub ☉}. An estimate of the size of the black hole sphere of influence in NGC 5273 puts it just at the limit of the resolution achievable with current ground-based large aperture telescopes. NGC 5273 is therefore an important future target for a black hole mass determination from stellar dynamical modeling, especially because it is the only nearby early-type galaxy hosting an AGN with a reverberation-based mass, allowing the best comparison for the masses determined from these two techniques.

The profiles of Fe K α line from the inhomogeneous accretion flow

Science.gov (United States)

Yu, Xiao-Di; Ma, Ren-Yi; Li, Ya-Ping; Zhang, Hui; Fang, Tao-Tao

2018-05-01

The clumpy disc, or inhomogeneous accretion flow, has been proposed to explain the properties of accreting black hole systems. However, the observational evidence remains to be explored. In this work, we calculate the profiles of Fe K α lines emitted from the inhomogeneous accretion flow through the ray-tracing technique, in order to find possible observable signals of the clumps. Compared with the skewed double-peaked profile of the continuous standard accretion disc, the lines show a multipeak structure when the emissivity index is not very steep. The peaks and wings are affected by the position and size of the cold clumps. When the clump is small and is located in the innermost region, due to the significant gravitational redshift, the blue wing can overlap with the red wing of the outer cold disc/clump, forming a fake peak or greatly enhancing the red peak. Given high enough resolution, it is easier to constrain the clumps around the supermassive black holes than the clumps in stellar mass black holes due to the thermal Doppler effect.

New line selected from irradiated cuttings of sweet potato

International Nuclear Information System (INIS)

Lu Shuyun; Wu Chongguang; Li Weiji; Feng Qihuan

1992-01-01

Some clonal lines of resistance to black rot were obtained from M 1 V 3 of Xu-18 variety. Through some regional tests, provincial yield trial and production test, the mutant line Nong-Da 601 (12-11-8) as spring sweet potato showed a better yield than the control, the dry matter content of Nong-Da 601 was also better than that of control, further more, the resistance to black rot of mutant selected in M 1 V 3 could be passed onto their progeny. The analysis of esterase isozyme showed zymogram variation between Nong-Da 601 and Xu-18. From the observation of the root tip cells, the chromosome bridge appeared obviously after irradiation, but the frequency of chromosome aberration in M 1 V 6 was decreased almost to the level of control (Xu-18). It seems that the changes of disease resistance from susceptible to resistant by irradiation was not due to chromosome aberration but due to gene mutation

Black holes

OpenAIRE

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

2001-01-01

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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

Boltzmann statistical consideration on the excitation mechanism of iron atomic lines emitted from glow discharge plasmas

Energy Technology Data Exchange (ETDEWEB)

Zhang Lei; Kashiwakura, Shunsuke; Wagatsuma, Kazuaki, E-mail: wagatuma@imr.tohoku.ac.jp

2011-11-15

A Boltzmann plot for many iron atomic lines having excitation energies of 3.3-6.9 eV was investigated in glow discharge plasmas when argon or neon was employed as the plasma gas. The plot did not show a linear relationship over a wide range of the excitation energy, but showed that the emission lines having higher excitation energies largely deviated from a normal Boltzmann distribution whereas those having low excitation energies (3.3-4.3 eV) well followed it. This result would be derived from an overpopulation among the corresponding energy levels. A probable reason for this is that excitations for the high-lying excited levels would be caused predominantly through a Penning-type collision with the metastable atom of argon or neon, followed by recombination with an electron and then stepwise de-excitations which can populate the excited energy levels just below the ionization limit of iron atom. The non-thermal excitation occurred more actively in the argon plasma rather than the neon plasma, because of a difference in the number density between the argon and the neon metastables. The Boltzmann plots yields important information on the reason why lots of Fe I lines assigned to high-lying excited levels can be emitted from glow discharge plasmas. - Highlights: Black-Right-Pointing-Pointer This paper shows the excitation mechanism of Fe I lines from a glow discharge plasma. Black-Right-Pointing-Pointer A Boltzmann distribution is studied among iron lines of various excitation levels. Black-Right-Pointing-Pointer We find an overpopulation of the high-lying energy levels from the normal distribution. Black-Right-Pointing-Pointer It is caused through Penning-type collision of iron atom with argon metastable atom.

On the Charter Question: Black Marxism and Black Nationalism

Science.gov (United States)

Stern, Mark; Hussain, Khuram

2015-01-01

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

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

Science.gov (United States)

Dumas, Michael J.; ross, kihana miraya

2016-01-01

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

THE BLACK HOLE MASS-GALAXY LUMINOSITY RELATIONSHIP FOR SLOAN DIGITAL SKY SURVEY QUASARS

International Nuclear Information System (INIS)

Salviander, S.; Shields, G. A.; Bonning, E. W.

2015-01-01

We investigate the relationship between the mass of the central supermassive black hole, M BH , and the host galaxy luminosity, L gal , in a sample of quasars from the Sloan Digital Sky Survey Data Release 7. We use composite quasar spectra binned by black hole mass and redshift to assess galaxy features that would otherwise be overwhelmed by noise in individual spectra. The black hole mass is calculated using the photoionization method, and the host galaxy luminosity is inferred from the depth of the Ca II H+K features in the composite spectra. We evaluate the evolution in the M BH -L gal relationship by examining the redshift dependence of Δ log M BH , the offset in M BH from the local M BH -L gal relationship. There is little systematic trend in Δ log M BH out to z = 0.8. Using the width of the [O III] emission line as a proxy for the stellar velocity dispersion, σ * , we find agreement of our derived host luminosities with the locally observed Faber-Jackson relation. This supports the utility of the width of the [O III] line as a proxy for σ * in statistical studies

A test of the massive binary black hole hypothesis - Arp 102B

Science.gov (United States)

Helpern, J. P.; Filippenko, Alexei V.

1988-01-01

The emission-line spectra of several AGN have broad peaks which are significantly displaced in velocity with respect to the host galaxy. An interpretation of this effect in terms of orbital motion of a binary black hole predicts periods of a few centuries. It is pointed out here that recent measurements of the masses and sizes of many low-luminosity AGN imply orbital periods much shorter than this. In particular, it is found that the elliptical galaxy Arp 102B is the most likely candidate for observation of radial velocity variations; its period is expected to be about 3 yr. The H-alpha line profile of Arp 102B has been measured for 5 yr without detecting any change in velocity, and it is thus found that a rather restrictive observational test of the massive binary black hole hypothesis already exists, albeit for this one object.

Black hole astrophysics

International Nuclear Information System (INIS)

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

1979-01-01

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

Black reefs: iron-induced phase shifts on coral reefs.

Science.gov (United States)

Kelly, Linda Wegley; Barott, Katie L; Dinsdale, Elizabeth; Friedlander, Alan M; Nosrat, Bahador; Obura, David; Sala, Enric; Sandin, Stuart A; Smith, Jennifer E; Vermeij, Mark J A; Williams, Gareth J; Willner, Dana; Rohwer, Forest

2012-03-01

The Line Islands are calcium carbonate coral reef platforms located in iron-poor regions of the central Pacific. Natural terrestrial run-off of iron is non-existent and aerial deposition is extremely low. However, a number of ship groundings have occurred on these atolls. The reefs surrounding the shipwreck debris are characterized by high benthic cover of turf algae, macroalgae, cyanobacterial mats and corallimorphs, as well as particulate-laden, cloudy water. These sites also have very low coral and crustose coralline algal cover and are call black reefs because of the dark-colored benthic community and reduced clarity of the overlying water column. Here we use a combination of benthic surveys, chemistry, metagenomics and microcosms to investigate if and how shipwrecks initiate and maintain black reefs. Comparative surveys show that the live coral cover was reduced from 40 to 60% to reefs on Millennium, Tabuaeran and Kingman. These three sites are relatively large (>0.75 km(2)). The phase shift occurs rapidly; the Kingman black reef formed within 3 years of the ship grounding. Iron concentrations in algae tissue from the Millennium black reef site were six times higher than in algae collected from reference sites. Metagenomic sequencing of the Millennium Atoll black reef-associated microbial community was enriched in iron-associated virulence genes and known pathogens. Microcosm experiments showed that corals were killed by black reef rubble through microbial activity. Together these results demonstrate that shipwrecks and their associated iron pose significant threats to coral reefs in iron-limited regions.

Black hole mass estimates and emission-line properties of a sample of redshift z > 6.5 quasars

Energy Technology Data Exchange (ETDEWEB)

De Rosa, Gisella; Peterson, Bradley M.; Frank, Stephan [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Venemans, Bram P.; Decarli, Roberto; Walter, Fabian [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Gennaro, Mario [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Simcoe, Robert A. [MIT-Kavli Center for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Dietrich, Matthias [Department of Physics and Astronomy, Ohio University, Clippinger Lab 251B, Athens, OH 45701 (United States); McMahon, Richard G.; Hewett, Paul C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Mortlock, Daniel J. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London, SW7 2AZ (United Kingdom); Simpson, Chris [Astrophysics Research Institute, Liverpool John Moores University, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom)

2014-08-01

We present the analysis of optical and near-infrared spectra of the only four z > 6.5 quasars known to date, discovered in the UKIDSS-LAS and VISTA-VIKING surveys. Our data set consists of new Very Large Telescope/X-Shooter and Magellan/FIRE observations. These are the best optical/NIR spectroscopic data that are likely to be obtained for the z > 6.5 sample using current 6-10 m facilities. We estimate the black hole (BH) mass, the Eddington ratio, and the Si IV/C IV, C III]/C IV, and Fe II/Mg II emission-line flux ratios. We perform spectral modeling using a procedure that allows us to derive a probability distribution for the continuum components and to obtain the quasar properties weighted upon the underlying distribution of continuum models. The z > 6.5 quasars show the same emission properties as their counterparts at lower redshifts. The z > 6.5 quasars host BHs with masses of ∼10{sup 9} M{sub ☉} that are accreting close to the Eddington luminosity ((log(L{sub Bol}/L{sub Edd})) = –0.4 ± 0.2), in agreement with what has been observed for a sample of 4.0 < z < 6.5 quasars. By comparing the Si IV/C IV and C III]/C IV flux ratios with the results obtained from luminosity-matched samples at z ∼ 6 and 2 ≤ z ≤ 4.5, we find no evidence of evolution of the line ratios with cosmic time. We compare the measured Fe II/Mg II flux ratios with those obtained for a sample of 4.0 < z < 6.4 sources. The two samples are analyzed using a consistent procedure. There is no evidence that the Fe II/Mg II flux ratio evolves between z = 7 and z = 4. Under the assumption that the Fe II/Mg II traces the Fe/Mg abundance ratio, this implies the presence of major episodes of chemical enrichment in the quasar hosts in the first ∼0.8 Gyr after the Big Bang.

Black-footed ferrets and recreational shooting influence the attributes of black-tailed prairie dog burrows

Science.gov (United States)

Biggins, Dean E.; Ramakrishnan, Shantini; Goldberg, Amanda R.; Eads, David A.

2012-01-01

Black-tailed prairie dogs (Cynomys ludovicianus) plug burrows occupied by black-footed ferrets (Mustela nigripes), and they also plug burrows to entomb dead prairie dogs. We further evaluated these phenomena by sampling connectivity and plugging of burrow openings on prairie dog colonies occupied by ferrets, colonies where recreational shooting was allowed, and colonies with neither shooting nor ferrets. We counted burrow openings on line surveys and within plots, classified surface plugging, and used an air blower to examine subsurface connectivity. Colonies with ferrets had lower densities of openings, fewer connected openings (suggesting increased subsurface plugging), and more surface plugs compared to colonies with no known ferrets. Colonies with recreational shooting had the lowest densities of burrow openings, and line-survey data suggested colonies with shooting had intermediate rates of surface plugging. The extent of surface and subsurface plugging could have consequences for the prairie dog community by changing air circulation and escape routes of burrow systems and by altering energetic relationships. Burrow plugging might reduce prairie dogs' risk of predation by ferrets while increasing risk of predation by American badgers (Taxidea taxus); however, the complexity of the trade-off is increased if plugging increases the risk of predation on ferrets by badgers. Prairie dogs expend more energy plugging and digging when ferrets or shooting are present, and ferrets increase their energy expenditures when they dig to remove those plugs. Microclimatic differences in plugged burrow systems may play a role in flea ecology and persistence of the flea-borne bacterium that causes plague (Yersinia pestis).

A Parallel Restoration for Black Start of Microgrids Considering Characteristics of Distributed Generations

Directory of Open Access Journals (Sweden)

Jing Wang

2017-12-01

Full Text Available The black start capability is vital for microgrids, which can potentially improve the reliability of the power grid. This paper proposes a black start strategy for microgrids based on a parallel restoration strategy. Considering the characteristics of distributed generations (DGs, an evaluation model, which is used to assess the black start capability of DGs, is established by adopting the variation coefficient method. Thus, the DGs with good black start capability, which are selected by a diversity sequence method, are restored first in parallel under the constraints of DGs and network. During the selection process of recovery paths, line weight and node importance degree are proposed under the consideration of the node topological importance and the load importance as well as the backbone network restoration time. Therefore, the whole optimization of the reconstructed network is realized. Finally, the simulation results verify the feasibility and effectiveness of the strategy.

A dust-parallax distance of 19 megaparsecs to the supermassive black hole in NGC 4151.

Science.gov (United States)

Hönig, Sebastian F; Watson, Darach; Kishimoto, Makoto; Hjorth, Jens

2014-11-27

The active galaxy NGC 4151 has a crucial role as one of only two active galactic nuclei for which black hole mass measurements based on emission line reverberation mapping can be calibrated against other dynamical techniques. Unfortunately, effective calibration requires accurate knowledge of the distance to NGC 4151, which is not at present available. Recently reported distances range from 4 to 29 megaparsecs. Strong peculiar motions make a redshift-based distance very uncertain, and the geometry of the galaxy and its nucleus prohibit accurate measurements using other techniques. Here we report a dust-parallax distance to NGC 4151 of 19.0(+2.4)(-2.6) megaparsecs. The measurement is based on an adaptation of a geometric method that uses the emission line regions of active galaxies. Because these regions are too small to be imaged with present technology, we use instead the ratio of the physical and angular sizes of the more extended hot-dust emission as determined from time delays and infrared interferometry. This distance leads to an approximately 1.4-fold increase in the dynamical black hole mass, implying a corresponding correction to emission line reverberation masses of black holes if they are calibrated against the two objects with additional dynamical masses.

Beyond the standard model of the disc-line spectral profiles from black hole accretion discs

Czech Academy of Sciences Publication Activity Database

Sochora, Vjačeslav; Karas, Vladimír; Svoboda, Jiří; Dovčiak, Michal

2014-01-01

Roč. 54, č. 4 (2014), s. 301-304 ISSN 1210-2709 R&D Projects: GA ČR(CZ) GC13-00070J Institutional support: RVO:67985815 Keywords : accretion discs * black hole physics * galactic nuclei Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

FLARE-LIKE VARIABILITY OF THE Mg II {lambda}2800 EMISSION LINE IN THE {gamma}-RAY BLAZAR 3C 454.3

Energy Technology Data Exchange (ETDEWEB)

Leon-Tavares, J. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Vaeisaelaentie 20, FI-21500 Piikkioe (Finland); Chavushyan, V.; Patino-Alvarez, V.; Carraminana, A.; Carrasco, L. [Instituto Nacional de Astrofisica Optica y Electronica (INAOE), Apartado Postal 51 y 216, 72000 Puebla (Mexico); Valtaoja, E. [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, FI-20100 Turku (Finland); Arshakian, T. G. [I. Physikalisches Institut, Universitaet zu Koeln, Zuelpicher Str. 77, D-50937 Koeln (Germany); Popovic, L. C. [Astronomical Observatory, Volgina 7, 11160 Belgrade 74 (Serbia); Tornikoski, M.; Laehteenmaeki, A. [Aalto University Metsaehovi Radio Observatory, Metsaehovintie 114, FI-02540 Kylmaelae (Finland); Lobanov, A. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany)

2013-02-01

We report the detection of a statistically significant flare-like event in the Mg II {lambda}2800 emission line of 3C 454.3 during the outburst of autumn 2010. The highest levels of emission line flux recorded over the monitoring period (2008-2011) coincide with a superluminal jet component traversing through the radio core. This finding crucially links the broad emission line fluctuations to the non-thermal continuum emission produced by relativistically moving material in the jet and hence to the presence of broad-line region clouds surrounding the radio core. If the radio core were located at several parsecs from the central black hole, then our results would suggest the presence of broad-line region material outside the inner parsec where the canonical broad-line region is envisaged to be located. We briefly discuss the implications of broad emission line material ionized by non-thermal continuum in the context of virial black hole mass estimates and gamma-ray production mechanisms.

Contemporary Black Theatre.

Science.gov (United States)

Thomas, Pearl

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

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Indian Academy of Sciences (India)

ture of Fe II and the uncertainties in the atomic data complicate theoretical models .... The Fe II template used in the optical range was set up by Marziani ... ous green line marks the best fit, and the dashed grey line marks the continuum level.

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

International Nuclear Information System (INIS)

Kol, Barak; Sorkin, Evgeny; Piran, Tsvi

2004-01-01

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

Primary black holes

International Nuclear Information System (INIS)

Novikov, I.; Polnarev, A.

1981-01-01

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

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

Science.gov (United States)

2012-11-26

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

Hsa-let-7a functions as a tumor suppressor in renal cell carcinoma cell lines by targeting c-myc

Energy Technology Data Exchange (ETDEWEB)

Liu, Yongchao; Yin, Bingde; Zhang, Changcun; Zhou, Libin [Department of Urology, Shanghai First People' s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200080 (China); Fan, Jie, E-mail: jief67@sina.com [Department of Urology, Shanghai First People' s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200080 (China)

2012-01-06

Highlights: Black-Right-Pointing-Pointer This study is the first to test the let-7a/c-myc loop in renal cell carcinoma cell lines. Black-Right-Pointing-Pointer Let-7a down-regulated c-myc in three renal cell carcinoma cell lines. Black-Right-Pointing-Pointer c-myc target genes were down-regulated because of the let-7a-mediated down-regulation of c-myc. Black-Right-Pointing-Pointer The let-7a/c-myc loop has a significant function in renal cell carcinoma cell lines. -- Abstract: Widespread functions of the c-myc pathway play a crucial role in renal cell carcinoma (RCC) carcinogenesis. Thus, we evaluated the connection between proto-oncogenic c-myc and anti-neoplastic hsa-let-7a (let-7a) in RCC cell lines. The levels of c-myc and let-7a in 3 RCC cell lines (769P, Caki-1 and 786O) were measured after transfecting the cells with let-7a mimics or a negative control. The change in c-myc protein level was confirmed by Western blot. The anti-neoplastic function of let-7a was evaluated using cell counting kit-8 (CCK-8) for proliferation analysis and cell flow cytometry for cell cycle analysis. The changes of downstream targets of c-myc were measured using reverse transcription quantitative real-time PCR (qRT-PCR). Our results suggest for the first time that let-7a acts as a tumor suppressor in RCC cell lines by down-regulating c-myc and c-myc target genes such as proliferating cell nuclear antigen (PCNA), cyclin D1 (CCND1) and the miR17-92 cluster, which is accompanied by proliferation inhibition and cell cycle arrest.

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

International Nuclear Information System (INIS)

Myung, Yun Soo

2008-01-01

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

Carriers' localization and thermal redistribution in post growth voluntarily tuned quantum dashes' size/composition distribution

International Nuclear Information System (INIS)

Alouane, M.H. Hadj; Helali, A.; Morris, D.; Maaref, H.; Aimez, V.; Salem, B.; Gendry, M.

2014-01-01

This paper treats the impact of post growth tuned InAs/InP quantum dashes' (QDas) size/composition distribution on carriers' localization and thermal redistribution. The spread of this distribution depends on the experimental conditions used for the phosphorus ion implantation enhanced intermixing process. Atypical temperature-dependent luminescence properties have been observed and found to be strongly dependent on the amount of QDas size/composition dispersion. The experimental results have been reproduced by a model that takes into account the width of the QDas localized states distribution and consequent thermally induced carriers' redistribution. This model gives critical temperature values marking the beginning and the end of carriers delocalization and thermal transfer processes via an intermixing induced carrier's transfer channel located below the wetting layer states. -- Highlights: • We examine optical properties of post growth tuned QDas size/composition distribution. • Carriers' localization and thermal redistribution within inhomogeneously intermixed QDas are the origin of the atypical temperature-dependent luminescence properties. • Localized states ensemble's model is successively used to interpret the experimental results. • The carriers thermal transfer processes occur via an intermixing induced channel located below the wetting layer states. • Intermixing degree strongly influence the critical temperatures marking the beginning and the end of the carriers thermal transfer processes

From binary black hole simulation to triple black hole simulation

International Nuclear Information System (INIS)

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

2011-01-01

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

Echoes from a Dying Star

Science.gov (United States)

Kohler, Susanna

2017-06-01

When a passing star is torn apart by a supermassive black hole, it emits a flare of X-ray, ultraviolet, and optical light. What can we learn from the infrared echo of a violent disruption like this one?Stellar DestructionOptical (black triangles) and infrared (blue circles and red squares) observations of F010042237. Day 0 marks the day the optical emission peaked. The infrared emission rises steadily through the end of the data. [Dou et al. 2017]Tidal disruption events occur when a star passes within the tidal radius of a supermassive black hole. After tidal forces pull the star apart, much of the stellar matter falls onto the black hole, radiating briefly in X-ray, ultraviolet and optical as it accretes. This signature rise and gradual fall of emission has allowed us to detect dozens of tidal disruption events thus far.One of the recently discovered candidate events is a little puzzling. Not only does the candidate in ultraluminous infrared galaxy F010042237 have an unusual host most disruptions occur in galaxies that are no longer star-forming, in contrast to this one but its optical light curve also shows an unusually long decay time.Now mid-infrared observations of this event have beenpresented by a team of scientists led by Liming Dou (Guangzhou University and Department of Education, Guangdong Province, China), revealing why this disruption is behaving unusually.Schematic of a convex dusty ring (red bows) that absorbs UV photons and re-emits in the infrared. It simultaneously scatters UV and optical photons into our line of sight. The dashed lines illustrate the delays at lags of 60 days, 1, 2, 3, 4, and 5 years. [Adapted from Dou et al. 2017]A Dusty Solution?The optical flare from F010042237s nucleus peaked in 2010, so Dou and collaborators obtained archival mid-infrared data from the WISE and NEOWISE missions from 2010 to 2016. The data show that the galaxy is quiescent in mid-infrared in 2010 but in data from three years later, the infrared emission has

Radiation transport around Kerr black holes

Science.gov (United States)

Schnittman, Jeremy David

This Thesis describes the basic framework of a relativistic ray-tracing code for analyzing accretion processes around Kerr black holes. We begin in Chapter 1 with a brief historical summary of the major advances in black hole astrophysics over the past few decades. In Chapter 2 we present a detailed description of the ray-tracing code, which can be used to calculate the transfer function between the plane of the accretion disk and the detector plane, an important tool for modeling relativistically broadened emission lines. Observations from the Rossi X-Ray Timing Explorer have shown the existence of high frequency quasi-periodic oscillations (HFQPOs) in a number of black hole binary systems. In Chapter 3, we employ a simple "hot spot" model to explain the position and amplitude of these HFQPO peaks. The power spectrum of the periodic X-ray light curve consists of multiple peaks located at integral combinations of the black hole coordinate frequencies, with the relative amplitude of each peak determined by the orbital inclination, eccentricity, and hot spot arc length. In Chapter 4, we introduce additional features to the model to explain the broadening of the QPO peaks as well as the damping of higher frequency harmonics in the power spectrum. The complete model is used to fit the power spectra observed in XTE J1550-564, giving confidence limits on each of the model parameters. In Chapter 5 we present a description of the structure of a relativistic alpha- disk around a Kerr black hole. Given the surface temperature of the disk, the observed spectrum is calculated using the transfer function mentioned above. The features of this modified thermal spectrum may be used to infer the physical properties of the accretion disk and the central black hole. In Chapter 6 we develop a Monte Carlo code to calculate the detailed propagation of photons from a hot spot emitter scattering through a corona surrounding the black hole. The coronal scattering has two major observable

THE DEMOGRAPHICS OF BROAD-LINE QUASARS IN THE MASS-LUMINOSITY PLANE. II. BLACK HOLE MASS AND EDDINGTON RATIO FUNCTIONS

Energy Technology Data Exchange (ETDEWEB)

Kelly, Brandon C. [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93107 (United States); Shen, Yue [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States)

2013-02-10

We employ a flexible Bayesian technique to estimate the black hole (BH) mass and Eddington ratio functions for Type 1 (i.e., broad line) quasars from a uniformly selected data set of {approx}58, 000 quasars from the Sloan Digital Sky Survey (SDSS) DR7. We find that the SDSS becomes significantly incomplete at M {sub BH} {approx}< 3 Multiplication-Sign 10{sup 8} M {sub Sun} or L/L {sub Edd} {approx}< 0.07, and that the number densities of Type 1 quasars continue to increase down to these limits. Both the mass and Eddington ratio functions show evidence of downsizing, with the most massive and highest Eddington ratio BHs experiencing Type 1 quasar phases first, although the Eddington ratio number densities are flat at z < 2. We estimate the maximum Eddington ratio of Type 1 quasars in the observable universe to be L/L {sub Edd} {approx} 3. Consistent with our results in Shen and Kelly, we do not find statistical evidence for a so-called sub-Eddington boundary in the mass-luminosity plane of broad-line quasars, and demonstrate that such an apparent boundary in the observed distribution can be caused by selection effect and errors in virial BH mass estimates. Based on the typical Eddington ratio in a given mass bin, we estimate growth times for the BHs in Type 1 quasars and find that they are comparable to or longer than the age of the universe, implying an earlier phase of accelerated (i.e., with higher Eddington ratios) and possibly obscured growth. The large masses probed by our sample imply that most of our BHs reside in what are locally early-type galaxies, and we interpret our results within the context of models of self-regulated BH growth.

Surface geometry of 5D black holes and black rings

International Nuclear Information System (INIS)

Frolov, Valeri P.; Goswami, Rituparno

2007-01-01

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

Critical emission from a high-spin black hole

Science.gov (United States)

Lupsasca, Alexandru; Porfyriadis, Achilleas P.; Shi, Yichen

2018-03-01

We consider a rapidly spinning black hole surrounded by an equatorial, geometrically thin, slowly accreting disk that is stationary and axisymmetric. We analytically compute the broadening of electromagnetic line emissions from the innermost part of the disk, which resides in the near-horizon region. The result is independent of the disk's surface emissivity and therefore universal. This is an example of critical behavior in astronomy that is potentially observable by current or future telescopes.

Black Holes

OpenAIRE

Townsend, P. K.

1997-01-01

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

Black silicon solar cells with black bus-bar strings

DEFF Research Database (Denmark)

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

2016-01-01

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

Black hole masses in active galactic nuclei

Science.gov (United States)

Denney, Kelly D.

2010-11-01

We present the complete results from two, high sampling-rate, multi-month, spectrophotometric reverberation mapping campaigns undertaken to obtain either new or improved Hbeta reverberation lag measurements for several relatively low-luminosity active galactic nuclei (AGNs). We have reliably measured the time delay between variations in the continuum and Hbeta emission line in seven local Seyfert 1 galaxies. These measurements are used to calculate the mass of the supermassive black hole at the center of each of these AGNs. We place our results in context to the most current calibration of the broad-line region (BLR) RBLR-L relationship, where our results remove many outliers and significantly reduce the scatter at the low-luminosity end of this relationship. A detailed analysis of the data from our high sampling rate, multi-month reverberation mapping campaign in 2007 reveals that the Hbeta emission region within the BLRs of several nearby AGNs exhibit a variety of kinematic behaviors. Through a velocity-resolved reverberation analysis of the broad Hbeta emission-line flux variations in our sample, we reconstruct velocity-resolved kinematic signals for our entire sample and clearly see evidence for outflowing, infalling, and virialized BLR gas motions in NGC 3227, NGC 3516, and NGC 5548, respectively. Finally, we explore the nature of systematic errors that can arise in measurements of black hole masses from single-epoch spectra of AGNs by utilizing the many epochs available for NGC 5548 and PG1229+204 from reverberation mapping databases. In particular, we examine systematics due to AGN variability, contamination due to constant spectral components (i.e., narrow lines and host galaxy flux), data quality (i.e., signal-to-noise ratio, S/N), and blending of spectral features. We investigate the effect that each of these systematics has on the precision and accuracy of single-epoch masses calculated from two commonly-used line-width measures by comparing these

Acceleration of the charged particles due to chaotic scattering in the combined black hole gravitational field and asymptotically uniform magnetic field

International Nuclear Information System (INIS)

Stuchlik, Zdenek; Kolos, Martin

2016-01-01

To test the role of large-scale magnetic fields in accretion processes, we study the dynamics of the charged test particles in the vicinity of a black hole immersed into an asymptotically uniform magnetic field. Using the Hamiltonian formalism of the charged particle dynamics, we examine chaotic scattering in the effective potential related to the black hole gravitational field combined with the uniform magnetic field. Energy interchange between the translational and oscillatory modes of the charged particle dynamics provides a mechanism for charged particle acceleration along the magnetic field lines. This energy transmutation is an attribute of the chaotic charged particle dynamics in the combined gravitational and magnetic fields only, the black hole rotation is not necessary for such charged particle acceleration. The chaotic scatter can cause a transition to the motion along the magnetic field lines with small radius of the Larmor motion or vanishing Larmor radius, when the speed of the particle translational motion is largest and it can be ultra-relativistic. We discuss the consequences of the model of ionization of test particles forming a neutral accretion disc, or heavy ions following off-equatorial circular orbits, and we explore the fate of heavy charged test particles after ionization where no kick of heavy ions is assumed and only the switch-on effect of the magnetic field is relevant. We demonstrate that acceleration and escape of the ionized particles can be efficient along the Kerr black hole symmetry axis parallel to the magnetic field lines. We show that a strong acceleration of the ionized particles to ultra-relativistic velocities is preferred in the direction close to the magnetic field lines. Therefore, the process of ionization of Keplerian discs around the Kerr black holes can serve as a model of relativistic jets. (orig.)

Acceleration of the charged particles due to chaotic scattering in the combined black hole gravitational field and asymptotically uniform magnetic field

Energy Technology Data Exchange (ETDEWEB)

Stuchlik, Zdenek; Kolos, Martin [Silesian University in Opava, Faculty of Philosophy and Science, Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Opava (Czech Republic)

2016-01-15

To test the role of large-scale magnetic fields in accretion processes, we study the dynamics of the charged test particles in the vicinity of a black hole immersed into an asymptotically uniform magnetic field. Using the Hamiltonian formalism of the charged particle dynamics, we examine chaotic scattering in the effective potential related to the black hole gravitational field combined with the uniform magnetic field. Energy interchange between the translational and oscillatory modes of the charged particle dynamics provides a mechanism for charged particle acceleration along the magnetic field lines. This energy transmutation is an attribute of the chaotic charged particle dynamics in the combined gravitational and magnetic fields only, the black hole rotation is not necessary for such charged particle acceleration. The chaotic scatter can cause a transition to the motion along the magnetic field lines with small radius of the Larmor motion or vanishing Larmor radius, when the speed of the particle translational motion is largest and it can be ultra-relativistic. We discuss the consequences of the model of ionization of test particles forming a neutral accretion disc, or heavy ions following off-equatorial circular orbits, and we explore the fate of heavy charged test particles after ionization where no kick of heavy ions is assumed and only the switch-on effect of the magnetic field is relevant. We demonstrate that acceleration and escape of the ionized particles can be efficient along the Kerr black hole symmetry axis parallel to the magnetic field lines. We show that a strong acceleration of the ionized particles to ultra-relativistic velocities is preferred in the direction close to the magnetic field lines. Therefore, the process of ionization of Keplerian discs around the Kerr black holes can serve as a model of relativistic jets. (orig.)

Probing the accretion flow and emission-line regions of M81, the nearest broad-lined low-luminosity AGN

Science.gov (United States)

Barth, Aaron

2017-08-01

The nucleus of M81 is an object of singular importance as a template for low-luminosity accretion flows onto supermassive black holes. We propose to obtain a complete, small-aperture, high S/N STIS UV/optical spectrum of the M81 nucleus and multi-filter WFC3 imaging covering the UV through near-IR. Such data have never previously been obtained with HST; the only prior archival UV/optical spectra of M81 have low S/N, incomplete wavelength coverage, and are strongly contaminated by starlight. Combined with new Chandra X-ray data, our proposed observations will comprise the definitive reference dataset on the spectral energy distribution of this benchmark low-luminosity AGN. These data will provide unique new constraints on the possible contribution of a truncated thin accretion disk to the AGN emission spectrum, clarifying a fundamental property of low-luminosity accretion flows. The data will additionally provide new insights into broad-line region structure and black hole mass scaling relationships at the lowest AGN luminosities, and spatially resolved diagnostics of narrow-line region excitation conditions at unprecedented spatial resolution to assess the impact of the AGN on the ionization state of the gas in the host galaxy bulge.

A REVERBERATION LAG FOR THE HIGH-IONIZATION COMPONENT OF THE BROAD-LINE REGION IN THE NARROW-LINE SEYFERT 1 Mrk 335

International Nuclear Information System (INIS)

Grier, C. J.; Peterson, B. M.; Pogge, R. W.; Martini, Paul; Zu, Y.; Kochanek, C. S.; Shappee, B. J.; Stanek, K. Z.; Araya Salvo, C.; Beatty, T. G.; Bird, J. C.; Denney, K. D.; Bentz, M. C.; Sergeev, S. G.; Borman, G. A.; Kaspi, S.; Bord, D. J.; Che, X.; Chen, C.; Cohen, S. A.

2012-01-01

We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 (NLS1) galaxy Mrk 335, collected over a 120 day span in the fall of 2010. From these data we measure the lag in the He II λ4686 broad emission line relative to the optical continuum to be 2.7 ± 0.6 days and the lag in the Hβλ4861 broad emission line to be 13.9 ± 0.9 days. Combined with the line width, the He II lag yields a black hole mass M BH = (2.6 ± 0.8) × 10 7 M ☉ . This measurement is consistent with measurements made using the Hβλ4861 line, suggesting that the He II emission originates in the same structure as Hβ, but at a much smaller radius. This constitutes the first robust lag measurement for a high-ionization line in an NLS1 galaxy and supports a scenario in which the He II emission originates from gas in virial motion rather than outflow.

A REVERBERATION LAG FOR THE HIGH-IONIZATION COMPONENT OF THE BROAD-LINE REGION IN THE NARROW-LINE SEYFERT 1 Mrk 335

Energy Technology Data Exchange (ETDEWEB)

Grier, C. J.; Peterson, B. M.; Pogge, R. W.; Martini, Paul; Zu, Y.; Kochanek, C. S.; Shappee, B. J.; Stanek, K. Z.; Araya Salvo, C.; Beatty, T. G.; Bird, J. C. [Department of Astronomy, The Ohio State University, 140 W 18th Avenue, Columbus, OH 43210 (United States); Denney, K. D. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Sergeev, S. G.; Borman, G. A. [Crimean Astrophysical Observatory, P/O Nauchny Crimea 98409 (Ukraine); Kaspi, S. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Bord, D. J. [Department of Natural Sciences, The University of Michigan-Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128 (United States); Che, X. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 41809 (United States); Chen, C.; Cohen, S. A. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); and others

2012-01-15

We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 (NLS1) galaxy Mrk 335, collected over a 120 day span in the fall of 2010. From these data we measure the lag in the He II {lambda}4686 broad emission line relative to the optical continuum to be 2.7 {+-} 0.6 days and the lag in the H{beta}{lambda}4861 broad emission line to be 13.9 {+-} 0.9 days. Combined with the line width, the He II lag yields a black hole mass M{sub BH} = (2.6 {+-} 0.8) Multiplication-Sign 10{sup 7} M{sub Sun }. This measurement is consistent with measurements made using the H{beta}{lambda}4861 line, suggesting that the He II emission originates in the same structure as H{beta}, but at a much smaller radius. This constitutes the first robust lag measurement for a high-ionization line in an NLS1 galaxy and supports a scenario in which the He II emission originates from gas in virial motion rather than outflow.

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

International Nuclear Information System (INIS)

Tomimatsu, Akira

2005-01-01

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

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.

BET bromodomain inhibition rescues erythropoietin differentiation of human erythroleukemia cell line UT7

Energy Technology Data Exchange (ETDEWEB)

Goupille, Olivier [CEA, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses (France); UMR INSERM U.962, University Paris XI, CEA, Fontenay-aux-Roses (France); Penglong, Tipparat [CEA, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses (France); UMR INSERM U.962, University Paris XI, CEA, Fontenay-aux-Roses (France); Thalassemia Research Center and Department of Clinical Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University (Thailand); Lefevre, Carine; Granger, Marine; Kadri, Zahra [CEA, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses (France); UMR INSERM U.962, University Paris XI, CEA, Fontenay-aux-Roses (France); Fucharoen, Suthat [Thalassemia Research Center and Department of Clinical Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University (Thailand); Maouche-Chretien, Leila [CEA, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses (France); UMR INSERM U.962, University Paris XI, CEA, Fontenay-aux-Roses (France); Leboulch, Philippe [CEA, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses (France); UMR INSERM U.962, University Paris XI, CEA, Fontenay-aux-Roses (France); Genetics Division, Department of Medicine, Brigham and Women' s Hospital and Harvard Medical School, Boston, MA (United States); Chretien, Stany, E-mail: stany.chretien@cea.fr [CEA, Institute of Emerging Diseases and Innovative Therapies, Fontenay-aux-Roses (France); UMR INSERM U.962, University Paris XI, CEA, Fontenay-aux-Roses (France)

2012-12-07

Highlights: Black-Right-Pointing-Pointer UT7 erythroleukemia cells are known to be refractory to differentiate. Black-Right-Pointing-Pointer Brief JQ1 treatment initiates the first steps of erythroid differentiation program. Black-Right-Pointing-Pointer Engaged UT7 cells then maturate in the presence of erythropoietin. Black-Right-Pointing-Pointer Sustained JQ1 treatment inhibits both proliferation and erythroid differentiation. -- Abstract: Malignant transformation is a multistep process requiring oncogenic activation, promoting cellular proliferation, frequently coupled to inhibition of terminal differentiation. Consequently, forcing the reengagement of terminal differentiation of transformed cells coupled or not with an inhibition of their proliferation is a putative therapeutic approach to counteracting tumorigenicity. UT7 is a human leukemic cell line able to grow in the presence of IL3, GM-CSF and Epo. This cell line has been widely used to study Epo-R/Epo signaling pathways but is a poor model for erythroid differentiation. We used the BET bromodomain inhibition drug JQ1 to target gene expression, including that of c-Myc. We have shown that only 2 days of JQ1 treatment was required to transitory inhibit Epo-induced UT7 proliferation and to restore terminal erythroid differentiation. This study highlights the importance of a cellular erythroid cycle break mediated by c-Myc inhibition before initiation of the erythropoiesis program and describes a new model for BET bromodomain inhibitor drug application.

Black Sea coastal forecasting system

Directory of Open Access Journals (Sweden)

A. I. Kubryakov

2012-03-01

Full Text Available The Black Sea coastal nowcasting and forecasting system was built within the framework of EU FP6 ECOOP (European COastalshelf sea OPerational observing and forecasting system project for five regions: the south-western basin along the coasts of Bulgaria and Turkey, the north-western shelf along the Romanian and Ukrainian coasts, coastal zone around of the Crimea peninsula, the north-eastern Russian coastal zone and the coastal zone of Georgia. The system operates in the real-time mode during the ECOOP project and afterwards. The forecasts include temperature, salinity and current velocity fields. Ecosystem model operates in the off-line mode near the Crimea coast.

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.

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

International Nuclear Information System (INIS)

Yazadjiev, Stoytcho S.

2006-01-01

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

Black holes, quantum theory and cosmology

International Nuclear Information System (INIS)

Penrose, Roger

2009-01-01

Some reasons are given for believing that the rules of quantum (field) theory must be changed when general relativity becomes seriously involved. If full quantum mechanical respect is paid to the principle of equivalence, we find that a superposition of gravitational fields leads to an illegal superposition of different vacua, giving support to a proposal for spontaneous quantum state reduction made earlier by Diosi, and then independently by the author. A different line of attack involves the over-riding role of black holes in the total entropy content of the universe, and in the operation of the 2nd Law of thermodynamics. The author's proposal of conformal cyclic cosmology is reviewed in order to highlight a seeming paradox, according to which the entropy of the universe of the remote future seems to return to the small kind of value that it had at the big bang. The paradox is resolved when we take into account the information loss that, from this perspective, necessarily occurs in Hawking's black-hole evaporation, with the accompanying loss of unitarity.

Black holes, quantum theory and cosmology

Science.gov (United States)

Penrose, Roger

2009-06-01

Some reasons are given for believing that the rules of quantum (field) theory must be changed when general relativity becomes seriously involved. If full quantum mechanical respect is paid to the principle of equivalence, we find that a superposition of gravitational fields leads to an illegal superposition of different vacua, giving support to a proposal for spontaneous quantum state reduction made earlier by Diósi, and then independently by the author. A different line of attack involves the over-riding role of black holes in the total entropy content of the universe, and in the operation of the 2nd Law of thermodynamics. The author's proposal of conformal cyclic cosmology is reviewed in order to highlight a seeming paradox, according to which the entropy of the universe of the remote future seems to return to the small kind of value that it had at the big bang. The paradox is resolved when we take into account the information loss that, from this perspective, necessarily occurs in Hawking's black-hole evaporation, with the accompanying loss of unitarity.

Black holes, quantum theory and cosmology

Energy Technology Data Exchange (ETDEWEB)

Penrose, Roger, E-mail: rouse@maths.ox.ac.u [Mathematical Institute, 24-29 St Giles, Oxford OX1 3LB (United Kingdom)

2009-06-01

Some reasons are given for believing that the rules of quantum (field) theory must be changed when general relativity becomes seriously involved. If full quantum mechanical respect is paid to the principle of equivalence, we find that a superposition of gravitational fields leads to an illegal superposition of different vacua, giving support to a proposal for spontaneous quantum state reduction made earlier by Diosi, and then independently by the author. A different line of attack involves the over-riding role of black holes in the total entropy content of the universe, and in the operation of the 2nd Law of thermodynamics. The author's proposal of conformal cyclic cosmology is reviewed in order to highlight a seeming paradox, according to which the entropy of the universe of the remote future seems to return to the small kind of value that it had at the big bang. The paradox is resolved when we take into account the information loss that, from this perspective, necessarily occurs in Hawking's black-hole evaporation, with the accompanying loss of unitarity.

H I OBSERVATIONS OF THE SUPERMASSIVE BINARY BLACK HOLE SYSTEM IN 0402+379

International Nuclear Information System (INIS)

Rodriguez, C.; Taylor, G. B.; Pihlstroem, Y. M.; Zavala, R. T.; Peck, A. B.

2009-01-01

We have recently discovered a supermassive binary black hole system with a projected separation between the two black holes of 7.3 pc in the radio galaxy 0402+379 (Rodriguez et al. 2006). This is the most compact supermassive binary black hole pair yet imaged by more than two orders of magnitude. We present Global VLBI observations at 1.3464 GHz of this radio galaxy, taken to improve the quality of the H I data. Two absorption lines are found toward the southern jet of the source, one redshifted by 370 ± 10 km s -1 and the other blueshifted by 700 ± 10 km s -1 with respect to the systemic velocity of the source, which, along with the results obtained for the opacity distribution over the source, suggests the presence of two mass clumps rotating around the central region of the source. We propose a model consisting of a geometrically thick disk, of which we only see a couple of clumps, that reproduces the velocities measured from the H I absorption profiles. These clumps rotate in circular Keplerian orbits around an axis that crosses one of the supermassive black holes of the binary system in 0402+379. We find an upper limit for the inclination angle of the twin jets of the source to the line of sight of θ = 66 deg., which, according to the proposed model, implies a lower limit on the central mass of ∼7 x 10 8 M sun and a lower limit for the scale height of the thick disk of ∼12 pc.

Truncation of the Inner Accretion Disk Around a Black Hole at Low Luminosity

Science.gov (United States)

Tomsick, John A.; Yamoka, Kazutaka; Corbel, Stephane; Kaaret, Philip; Kalemci, Emrah; Migliari, Simone

2011-01-01

Most black hole binaries show large changes in X-ray luminosity caused primarily by variations in mass accretion rate. An important question for understanding black hole accretion and jet production is whether the inner edge of the accretion disk recedes at low accretion rate. Measurements of the location of the inner edge (R(sub in)) can be made using iron emission lines that arise due to fluorescence of iron in the disk, and these indicate that R(sub in) is very close to the black hole at high and moderate luminosities (greater than or equal to 1% of the Eddington luminosity, L(sub Edd). Here, we report on X-ray observations of the black hole GX 339-4 in the hard state by Suzaku and the Rossi X-ray Timing Explorer that extend iron line studies to 0.14% L(sub Edd) and show that R(sub in) increases by a factor of greater than 27 over the value found when GX 339-4 was bright. The exact value of R(sub in) depends on the inclination of the inner disk (i), and we derive 90% confidence limits of R(sub in) greater than 35 R(sub g) at i = 0 degrees and R(sub in) greater than 175 R(sub g) at i = 30 degrees. This provides direct evidence that the inner portion of the disk is not present at low luminosity, allowing for the possibility that the inner disk is replaced by advection- or magnetically dominated accretion flows.

EDDINGTON RATIO DISTRIBUTION OF X-RAY-SELECTED BROAD-LINE AGNs AT 1.0 < z < 2.2

International Nuclear Information System (INIS)

Suh, Hyewon; Hasinger, Günther; Steinhardt, Charles; Silverman, John D.; Schramm, Malte

2015-01-01

We investigate the Eddington ratio distribution of X-ray-selected broad-line active galactic nuclei (AGNs) in the redshift range 1.0 < z < 2.2, where the number density of AGNs peaks. Combining the optical and Subaru/Fiber Multi Object Spectrograph near-infrared spectroscopy, we estimate black hole masses for broad-line AGNs in the Chandra Deep Field South (CDF-S), Extended Chandra Deep Field South (E-CDF-S), and the XMM-Newton Lockman Hole (XMM-LH) surveys. AGNs with similar black hole masses show a broad range of AGN bolometric luminosities, which are calculated from X-ray luminosities, indicating that the accretion rate of black holes is widely distributed. We find a substantial fraction of massive black holes accreting significantly below the Eddington limit at z ≲ 2, in contrast to what is generally found for luminous AGNs at high redshift. Our analysis of observational selection biases indicates that the “AGN cosmic downsizing” phenomenon can be simply explained by the strong evolution of the comoving number density at the bright end of the AGN luminosity function, together with the corresponding selection effects. However, one might need to consider a correlation between the AGN luminosity and the accretion rate of black holes, in which luminous AGNs have higher Eddington ratios than low-luminosity AGNs, in order to understand the relatively small fraction of low-luminosity AGNs with high accretion rates in this epoch. Therefore, the observed downsizing trend could be interpreted as massive black holes with low accretion rates, which are relatively fainter than less-massive black holes with efficient accretion

The supermassive black hole coincident with the luminous transient ASASSN-15lh

Science.gov (United States)

Krühler, T.; Fraser, M.; Leloudas, G.; Schulze, S.; Stone, N. C.; van Velzen, S.; Amorin, R.; Hjorth, J.; Jonker, P. G.; Kann, D. A.; Kim, S.; Kuncarayakti, H.; Mehner, A.; Nicuesa Guelbenzu, A.

2018-02-01

The progenitors of astronomical transients are linked to a specific stellar population and galactic environment, and observing their host galaxies hence constrains the physical nature of the transient itself. Here, we use imaging from the Hubble Space Telescope, and spatially resolved, medium-resolution spectroscopy from the Very Large Telescope obtained with X-shooter and MUSE to study the host of the very luminous transient ASASSN-15lh. The dominant stellar population at the transient site is old (around 1 to 2 Gyr) without signs of recent star formation. We also detect emission from ionized gas, originating from three different, time invariable, narrow components of collisionally excited metal and Balmer lines. The ratios of emission lines in the Baldwin-Phillips-Terlevich diagnostic diagram indicate that the ionization source is a weak active galactic nucleus with a black hole mass of M• = 5-3+8 × 108 M⊙, derived through the M•-σ relation. The narrow line components show spatial and velocity offsets on scales of 1 kpc and 500 km s-1, respectively; these offsets are best explained by gas kinematics in the narrow-line region. The location of the central component, which we argue is also the position of the supermassive black hole, aligns with that of the transient within an uncertainty of 170 pc. Using this positional coincidence as well as other similarities with the hosts of tidal disruption events, we strengthen the argument that the transient emission observed as ASASSN-15lh is related to the disruption of a star around a supermassive black hole, most probably spinning with a Kerr parameter a• ≳ 0.5. Based on observations at ESO, Program IDs: 097.D-1054, 297.B-5035, 099.D-0115.The data used in this manuscript are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/610/A14

Magnetic Neutral Points and Electric Lines of Force in Strong Gravity of a Rotating Black Hole

Czech Academy of Sciences Publication Activity Database

Karas, Vladimír; Kopáček, Ondřej; Kunneriath, Devaky

2013-01-01

Roč. 3, 3A (2013), s. 18-24 ISSN 2161-4717 R&D Projects: GA ČR(CZ) GC13-00070J Institutional support: RVO:67985815 Keywords : galaxies * nuclei * black hole physics Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

Conservation laws and two-dimensional black holes in dilaton gravity

Science.gov (United States)

Mann, R. B.

1993-05-01

A very general class of Lagrangians which couple scalar fields to gravitation and matter in two spacetime dimensions is investigated. It is shown that a vector field exists along whose flow lines the stress-energy tensor is conserved, regardless of whether or not the equations of motion are satisfied or if any Killing vectors exist. Conditions necessary for the existence of Killing vectors are derived. A new set of two-dimensional (2D) black-hole solutions is obtained for one particular member within this class of Lagrangians, which couples a Liouville field to 2D gravity in a novel way. One solution of this theory bears an interesting resemblance to the 2D string-theoretic black hole, yet contains markedly different thermodynamic properties.

Super-Eddington accreting massive black holes as long-lived cosmological standards.

Science.gov (United States)

Wang, Jian-Min; Du, Pu; Valls-Gabaud, David; Hu, Chen; Netzer, Hagai

2013-02-22

Super-Eddington accreting massive black holes (SEAMBHs) reach saturated luminosities above a certain accretion rate due to photon trapping and advection in slim accretion disks. We show that these SEAMBHs could provide a new tool for estimating cosmological distances if they are properly identified by hard x-ray observations, in particular by the slope of their 2-10 keV continuum. To verify this idea we obtained black hole mass estimates and x-ray data for a sample of 60 narrow line Seyfert 1 galaxies that we consider to be the most promising SEAMBH candidates. We demonstrate that the distances derived by the new method for the objects in the sample get closer to the standard luminosity distances as the hard x-ray continuum gets steeper. The results allow us to analyze the requirements for using the method in future samples of active black holes and to demonstrate that the expected uncertainty, given large enough samples, can make them into a useful, new cosmological ruler.

On the localization of four-dimensional brane-world black holes

International Nuclear Information System (INIS)

Kanti, P; Pappas, N; Zuleta, K

2013-01-01

In the context of brane-world models, we pursue the question of the existence of five-dimensional solutions describing regular black holes localized close to the brane. Employing a perturbed Vaidya-type line-element embedded in a warped fifth dimension, we attempt to localize the extended black-string singularity, and to restore the regularity of the AdS spacetime at a finite distance from the brane by introducing an appropriate bulk energy–momentum tensor. As a source for this bulk matter, we are considering a variety of non-ordinary field-theory models of scalar fields either minimally coupled to gravity, but including non-canonical kinetic terms, mixing terms, derivative interactions and ghosts, or non-minimally coupled to gravity through a general coupling to the Ricci scalar. In all models considered, even in those characterized by a high degree of flexibility, a negative result was reached. Our analysis demonstrates how difficult the analytic construction of a localized brane-world black hole may be in the context of a well-defined field-theory model. Finally, with regard to the question of the existence or not of a static classical black-hole solution on the brane, our analysis suggests that such solutions could in principle exist; however, the associated field configuration itself has to be dynamic. (paper)

The Black Lives Matter Movement and Historically Black Colleges and Universities

Science.gov (United States)

Gasman, Marybeth

2017-01-01

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

A REVERBERATION-BASED BLACK HOLE MASS FOR MCG-06-30-15

International Nuclear Information System (INIS)

Bentz, Misty C.; Crenshaw, D. Michael; Ou-Yang, Benjamin; Cackett, Edward M.; Horne, Keith; Street, Rachel

2016-01-01

We present the results of a reverberation campaign targeting MGC-06-30-15. Spectrophotometric monitoring and broad-band photometric monitoring over the course of four months in spring 2012 allowed a determination of a time delay in the broad H β emission line of τ = 5.3 ± 1.8 days in the rest frame of the active galactic nucleus (AGN). Combined with the width of the variable portion of the emission line, we determine a black hole mass of M BH = (1.6 ± 0.4) × 10 6 M ⊙ . Both the H β time delay and the black hole mass are in good agreement with expectations from the R BLR – L and M BH – σ ⋆ relationships for other reverberation-mapped AGNs. The H β time delay is also in good agreement with the relationship between H β and broad-band near-IR delays, in which the effective size of the broad-line region is ∼4–5 times smaller than the inner edge of the dust torus. Additionally, the reverberation-based mass is in good agreement with estimates from the scaling relationship of the break in the X-ray power spectral density, and with constraints based on stellar kinematics derived from integral field spectroscopy of the inner ∼0.5 kpc of the galaxy.

A REVERBERATION-BASED BLACK HOLE MASS FOR MCG-06-30-15

Energy Technology Data Exchange (ETDEWEB)

Bentz, Misty C.; Crenshaw, D. Michael; Ou-Yang, Benjamin [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States); Cackett, Edward M. [Department of Physics and Astronomy, Wayne State University, 666 W. Hancock St., Detroit, MI 48201 (United States); Horne, Keith [SUPA Physics and Astronomy, University of St. Andrews, Fife KY16 9SS (United Kingdom); Street, Rachel, E-mail: bentz@astro.gsu.edu [Las Cumbres Observatory Global Telescope Network, 6740B Cortona Drive, Goleta, CA 93117 (United States)

2016-10-20

We present the results of a reverberation campaign targeting MGC-06-30-15. Spectrophotometric monitoring and broad-band photometric monitoring over the course of four months in spring 2012 allowed a determination of a time delay in the broad H β emission line of τ = 5.3 ± 1.8 days in the rest frame of the active galactic nucleus (AGN). Combined with the width of the variable portion of the emission line, we determine a black hole mass of M {sub BH} = (1.6 ± 0.4) × 10{sup 6} M {sub ⊙}. Both the H β time delay and the black hole mass are in good agreement with expectations from the R {sub BLR}– L and M {sub BH}– σ {sub ⋆} relationships for other reverberation-mapped AGNs. The H β time delay is also in good agreement with the relationship between H β and broad-band near-IR delays, in which the effective size of the broad-line region is ∼4–5 times smaller than the inner edge of the dust torus. Additionally, the reverberation-based mass is in good agreement with estimates from the scaling relationship of the break in the X-ray power spectral density, and with constraints based on stellar kinematics derived from integral field spectroscopy of the inner ∼0.5 kpc of the galaxy.

A Multiwavelength Study of POX 52, a Dwarf Seyfert Galaxy with an Intermediate Mass Black Hole

Science.gov (United States)

Barth, Aaron

2004-09-01

POX 52 is a Seyfert 1 galaxy with unprecedented properties: its host galaxy is a dwarf elliptical, and its stellar velocity dispersion is only 36 km/s. The stellar velocity dispersion and the broad emission-line widths both suggest a black hole mass of order 10^5 solar masses. We request HST ACS/HRC imaging to perform a definitive measurement of the host galaxy structure; STIS UV and optical spectroscopy to study the nonstellar continuum and the structure of the broad-line region; and Chandra ACIS imaging to investigate the spectral and variability properties of the X-ray emission. The results of this program will give a detailed understanding of the host galaxy and accretion properties of one of the very few known black holes in the mass range around 10^5 solar masses.

Umfazi akangeni ebuhlanti emzini … A womanist dialogue with Black Theology of Liberation in the 21st century

Directory of Open Access Journals (Sweden)

Fundiswa Kobo

2016-08-01

Full Text Available As reflected in the title, this article is premised by pervasive attitudes arising from a complex interplay of cultural practices, which have succeeded in dislocating black women from what is perceived to be black men’s sites, ebuhlanti (kraal, esuthwini (initiation school; locating them in culturally designated womanised sites eziko/egoqweni (kitchen and household, ekuzaleni nasekukhuliseni abantwana (child birth and rearing in a patriarchal society. The crux of the article lies in its attempt to re-locate both men and women by its adoption of ‘a hard-line pro-black position’. Womanists acknowledge the interlocution of black men and thus suggest firstly, a shift in mind-set for both to view these sites as life giving and therefore to look for convergences. The article is thus a dialogue between a womanist and Black Theology of Liberation in the 21st century for the purpose of understanding liberation of black people for the liberation of humanity.

CONSTRAINING JET PRODUCTION SCENARIOS BY STUDIES OF NARROW-LINE RADIO GALAXIES

Energy Technology Data Exchange (ETDEWEB)

Sikora, Marek [Nicolaus Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw (Poland); Stasinska, Grazyna [LUTH, Observatoire de Paris, CNRS, Universite Paris Diderot, Place Jules Janssen, F-92190 Meudon (France); Koziel-Wierzbowska, Dorota [Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Krakow (Poland); Madejski, Greg M. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Asari, Natalia V., E-mail: sikora@camk.edu.pl [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

2013-03-01

We study a large sample of narrow-line radio galaxies (NLRGs) with extended radio structures. Using 1.4 GHz radio luminosities L {sub 1.4}, narrow optical emission line luminosities L {sub [OIII]} and L{sub H{sub {alpha}}}, as well as black hole masses M {sub BH} derived from stellar velocity dispersions measured from the optical spectra obtained with the Sloan Digital Sky Survey, we find that (1) NLRGs cover about four decades of the Eddington ratio, {lambda} {identical_to} L {sub bol}/L {sub Edd}{proportional_to}L {sub line}/M {sub BH}; (2) L {sub 1.4}/M {sub BH} strongly correlates with {lambda}; and (3) radio loudness, R{identical_to}L{sub 1.4}/L{sub line}, strongly anti-correlates with {lambda}. A very broad range of the Eddington ratio indicates that the parent population of NLRGs includes both radio-loud quasars (RLQs) and broad-line radio galaxies (BLRGs). The correlations they obey and their high jet production efficiencies favor a jet production model which involves the so-called magnetically choked accretion scenario. In this model, production of the jet is dominated by the Blandford-Znajek mechanism, and the magnetic fields in the vicinity of the central black hole are confined by the ram pressure of the accretion flow. Since large net magnetic flux accumulated in central regions of the accretion flow required by the model can take place only via geometrically thick accretion, we speculate that the massive, 'cold' accretion events associated with luminous emission-line active galactic nucleus can be accompanied by an efficient jet production only if preceded by a hot, very sub-Eddington accretion phase.

BDNF, produced by a TPO-stimulated megakaryocytic cell line, regulates autocrine proliferation

Energy Technology Data Exchange (ETDEWEB)

Tamura, Shogo [Graduate School of Health Sciences, Hokkaido University, Sapporo (Japan); Research Fellow of the Japan Society for the Promotion of Science, Tokyo (Japan); Nagasawa, Ayumi; Masuda, Yuya; Tsunematsu, Tetsuya [Graduate School of Health Sciences, Hokkaido University, Sapporo (Japan); Hayasaka, Koji; Matsuno, Kazuhiko; Shimizu, Chikara [Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Sapporo (Japan); Ozaki, Yukio [Department of Clinical and Laboratory Medicine, Faculty of Medicine, University of Yamanashi (Japan); Moriyama, Takanori, E-mail: moriyama@hs.hokuda.ac.jp [Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo (Japan)

2012-10-26

Highlights: Black-Right-Pointing-Pointer It has been thought that BDNF is not produced in the megakaryocytic lineage. Black-Right-Pointing-Pointer MEG-01 produces BDNF upon TPO stimulation and regulates its proliferation. Black-Right-Pointing-Pointer BDNF accelerates proliferation of MEG-01 in an autocrine manner. Black-Right-Pointing-Pointer BDNF may be an autocrine MEG-CSF, which regulates megakaryopoiesis. -- Abstract: While human platelets release endogenous brain-derived neurotrophic factor (BDNF) upon activation, a previous report on MEG-01, a megakaryocytic cell line, found no trace of BDNF production, and the pathophysiological function of platelet BDNF has remained elusive. In the present study, we demonstrate that MEG-01 produces BDNF in the presence of TPO and that this serves to potentiate cell proliferation. Our in vitro findings suggest that BDNF regulates MEG-01 proliferation in an autocrine manner, and we suggest that BDNF may be a physiological autocrine regulator of megakaryocyte progenitors.

Post-depositional enrichment of black soot in snow-pack and accelerated melting of Tibetan glaciers

International Nuclear Information System (INIS)

Xu Baiqing; Joswiak, Daniel R; Zhao Huabiao; Cao Junji; Liu Xianqin; He Jianqiao

2012-01-01

The post-depositional enrichment of black soot in snow-pack was investigated by measuring the redistribution of black soot along monthly snow-pits on a Tien Shan glacier. The one-year experiment revealed that black soot was greatly enriched, defined as the ratio of concentration to original snow concentration, in the unmelted snow-pack by at least an order of magnitude. Greatest soot enrichment was observed in the surface snow and the lower firn-pack within the melt season percolation zone. Black carbon (BC) concentrations as high as 400 ng g −1 in the summer surface snow indicate that soot can significantly contribute to glacier melt. BC concentrations reaching 3000 ng g −1 in the bottom portion of the firn pit are especially concerning given the expected equilibrium-line altitude (ELA) rise associated with future climatic warming, which would expose the dirty underlying firn and ice. Since most of the accumulation area on Tibetan glaciers is within the percolation zone where snow densification is characterized by melting and refreezing, the enrichment of black soot in the snow-pack is of foremost importance. Results suggest the effect of black soot on glacier melting may currently be underestimated. (letter)

Black-hole horizons in modified spacetime structures arising from canonical quantum gravity

International Nuclear Information System (INIS)

Bojowald, Martin; Paily, George M; Reyes, Juan D; Tibrewala, Rakesh

2011-01-01

Several properties of canonical quantum gravity modify spacetime structures, sometimes to the degree that no effective line elements exist to describe the geometry. An analysis of solutions, for instance in the context of black holes, then requires new insights. In this paper, standard definitions of horizons in spherical symmetry are first reformulated canonically, and then evaluated for solutions of equations and constraints modified by inverse-triad corrections of loop quantum gravity. When possible, a spacetime analysis is performed which reveals a mass threshold for black holes and small changes to Hawking radiation. For more general conclusions, canonical perturbation theory is developed to second order to include back-reaction from matter. The results shed light on the questions of whether renormalization of Newton's constant or other modifications of horizon conditions should be taken into account in computations of black-hole entropy in loop quantum gravity.

Black hole levitron

International Nuclear Information System (INIS)

Arsiwalla, Xerxes D.; Verlinde, Erik P.

2010-01-01

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

Black Holes

OpenAIRE

Horowitz, Gary T.; Teukolsky, Saul A.

1998-01-01

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

The XMM-Newton spectrum of a candidate recoiling supermassive black hole: An elusive inverted P-Cygni profile

Energy Technology Data Exchange (ETDEWEB)

Lanzuisi, G.; Civano, F.; Marchesi, S.; Hickox, R. [Department of Physics and Astronomy, Dartmouth College, Wilder Laboratory, Hanover, NH 03855 (United States); Comastri, A.; Cappelluti, N. [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Costantini, E. [SRON, Netherlands Institute for Space Research, Sorbonnelaan, 2, 3584 CA Utrecht (Netherlands); Elvis, M.; Fruscione, A. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Mainieri, V. [European Southern Observatory, Karl-Schwarschild-Strasse 2, D-85748 Garching bei Munchen (Germany); Jahnke, K. [Max Planck Institute for Astronomy, Konigstuhl 17, D-69117 Heidelberg (Germany); Komossa, S. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Piconcelli, E. [INAF-Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone (Italy); Vignali, C.; Brusa, M. [Dipartimento di Astronomia, Universitá degli Studi di Bologna, via Ranzani 1, I-40127 Bologna (Italy)

2013-11-20

We present a detailed spectral analysis of new XMM-Newton data of the source CXOC J100043.1+020637, also known as CID-42, detected in the COSMOS survey at z = 0.359. Previous works suggested that CID-42 is a candidate recoiling supermassive black hole (SMBH) showing also an inverted P-Cygni profile in the X-ray spectra at ∼6 keV (rest) with an iron emission line plus a redshifted absorption line (detected at 3σ in previous XMM-Newton and Chandra observations). Detailed analysis of the absorption line suggested the presence of ionized material flowing into the black hole at high velocity. In the new long XMM-Newton observation, while the overall spectral shape remains constant, the continuum 2-10 keV flux decrease of ∼20% with respect to previous observation and the absorption line is undetected. The upper limit on the intensity of the absorption line is EW < 162 eV. Extensive Monte Carlo simulations show that the nondetection of the line is solely due to variation in the properties of the inflowing material, in agreement with the transient nature of these features, and that the intensity of the line is lower than the previously measured with a probability of 98.8%. In the scenario of CID-42 as a recoiling SMBH, the absorption line can be interpreted as being due to an inflow of gas with variable density that is located in the proximity of the SMBH and recoiling with it. New monitoring observations will be requested to further characterize this line.

Search for black holes

International Nuclear Information System (INIS)

Cherepashchuk, Anatolii M

2003-01-01

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

Noncommutative black holes

Energy Technology Data Exchange (ETDEWEB)

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

2007-11-15

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

X-Ray Emission from Active Galactic Nuclei with Intermediate-Mass Black Holes

Science.gov (United States)

Dewangan, G. C.; Mathur, S.; Griffiths, R. E.; Rao, A. R.

2008-12-01

We present a systematic X-ray study of eight active galactic nuclei (AGNs) with intermediate-mass black holes (MBH ~ 8-95 × 104 M⊙) based on 12 XMM-Newton observations. The sample includes the two prototype AGNs in this class—NGC 4395 and POX 52 and six other AGNs discovered with the Sloan Digitized Sky Survey. These AGNs show some of the strongest X-ray variability, with the normalized excess variances being the largest and the power density break timescales being the shortest observed among radio-quiet AGNs. The excess-variance-luminosity correlation appears to depend on both the BH mass and the Eddington luminosity ratio. The break timescale-black hole mass relations for AGN with IMBHs are consistent with that observed for massive AGNs. We find that the FWHM of the Hβ/Hα line is uncorrelated with the BH mass, but shows strong anticorrelation with the Eddington luminosity ratio. Four AGNs show clear evidence for soft X-ray excess emission (kTin ~ 150-200 eV). X-ray spectra of three other AGNs are consistent with the presence of the soft excess emission. NGC 4395 with lowest L/LEdd lacks the soft excess emission. Evidently small black mass is not the primary driver of strong soft X-ray excess emission from AGNs. The X-ray spectral properties and optical-to-X-ray spectral energy distributions of these AGNs are similar to those of Seyfert 1 galaxies. The observed X-ray/UV properties of AGNs with IMBHs are consistent with these AGNs being low-mass extensions of more massive AGNs, those with high Eddington luminosity ratio looking more like narrow-line Seyfert 1 s and those with low L/LEdd looking more like broad-line Seyfert 1 galaxies.

Black hole critical phenomena without black holes

Indian Academy of Sciences (India)

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

Black widow spider

Science.gov (United States)

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

Hunting for Supermassive Black Holes in Nearby Galaxies With the Hobby-Eberly Telescope

Science.gov (United States)

van den Bosch, Remco C. E.; Gebhardt, Karl; Gültekin, Kayhan; Yıldırım, Akin; Walsh, Jonelle L.

2015-05-01

We have conducted an optical long-slit spectroscopic survey of 1022 galaxies using the 10 m Hobby-Eberly Telescope (HET) at McDonald Observatory. The main goal of the HET Massive Galaxy Survey (HETMGS) is to find nearby galaxies that are suitable for black hole mass measurements. In order to measure accurately the black hole mass, one should kinematically resolve the region where the black hole dominates the gravitational potential. For most galaxies, this region is much less than an arcsecond. Thus, black hole masses are best measured in nearby galaxies with telescopes that obtain high spatial resolution. The HETMGS focuses on those galaxies predicted to have the largest sphere-of-influence, based on published stellar velocity dispersions or the galaxy fundamental plane. To ensure coverage over galaxy types, the survey targets those galaxies across a face-on projection of the fundamental plane. We present the sample selection and resulting data products from the long-slit observations, including central stellar kinematics and emission line ratios. The full data set, including spectra and resolved kinematics, is available online. Additionally, we show that the current crop of black hole masses are highly biased toward dense galaxies and that especially large disks and low dispersion galaxies are under-represented. This survey provides the necessary groundwork for future systematic black hole mass measurement campaigns.

HUNTING FOR SUPERMASSIVE BLACK HOLES IN NEARBY GALAXIES WITH THE HOBBY–EBERLY TELESCOPE

International Nuclear Information System (INIS)

Bosch, Remco C. E. van den; Yıldırım, Akin; Gebhardt, Karl; Walsh, Jonelle L.; Gültekin, Kayhan

2015-01-01

We have conducted an optical long-slit spectroscopic survey of 1022 galaxies using the 10 m Hobby–Eberly Telescope (HET) at McDonald Observatory. The main goal of the HET Massive Galaxy Survey (HETMGS) is to find nearby galaxies that are suitable for black hole mass measurements. In order to measure accurately the black hole mass, one should kinematically resolve the region where the black hole dominates the gravitational potential. For most galaxies, this region is much less than an arcsecond. Thus, black hole masses are best measured in nearby galaxies with telescopes that obtain high spatial resolution. The HETMGS focuses on those galaxies predicted to have the largest sphere-of-influence, based on published stellar velocity dispersions or the galaxy fundamental plane. To ensure coverage over galaxy types, the survey targets those galaxies across a face-on projection of the fundamental plane. We present the sample selection and resulting data products from the long-slit observations, including central stellar kinematics and emission line ratios. The full data set, including spectra and resolved kinematics, is available online. Additionally, we show that the current crop of black hole masses are highly biased toward dense galaxies and that especially large disks and low dispersion galaxies are under-represented. This survey provides the necessary groundwork for future systematic black hole mass measurement campaigns

A Dancing Black Hole

Science.gov (United States)

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

2002-04-01

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

A LINK BETWEEN X-RAY EMISSION LINES AND RADIO JETS IN 4U 1630-47?

Energy Technology Data Exchange (ETDEWEB)

Neilsen, Joseph [Department of Astronomy, Boston University, Boston, MA 02215 (United States); Coriat, Mickaël [Department of Astronomy, University of Cape Town, Private Bag X3, Rondebosch 7701 (South Africa); Fender, Rob; Broderick, Jess W. [Department of Physics, Oxford University, Oxford OX1 3RH (United Kingdom); Lee, Julia C. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Ponti, Gabriele [Max Planck Institute fur Extraterrestriche Physik, D-85748 Garching (Germany); Tzioumis, Anastasios K.; Edwards, Philip G., E-mail: neilsenj@bu.edu [CSIRO Astronomy and Space Science, Australia Telescope National Facility, P.O. Box 76, Epping, NSW 1710 (Australia)

2014-03-20

Recently, Díaz Trigo et al. reported an XMM-Newton detection of relativistically Doppler-shifted emission lines associated with steep-spectrum radio emission in the stellar-mass black hole candidate 4U 1630-47 during its 2012 outburst. They interpreted these lines as indicative of a baryonic jet launched by the accretion disk. Here we present a search for the same lines earlier in the same outburst using high-resolution X-ray spectra from the Chandra HETGS. While our observations (eight months prior to the XMM-Newton campaign) also coincide with detections of steep spectrum radio emission by the Australia Telescope Compact Array, we find no evidence for any relativistic X-ray emission lines. Indeed, despite ∼5 × brighter radio emission, our Chandra spectra allow us to place an upper limit on the flux in the blueshifted Fe XXVI line that is ≳ 20 × weaker than the line observed by Díaz Trigo et al. We explore several scenarios that could explain our differing results, including variations in the geometry of the jet or a mass-loading process or jet baryon content that evolves with the accretion state of the black hole. We also consider the possibility that the radio emission arises in an interaction between a jet and the nearby interstellar medium, in which case the X-ray emission lines might be unrelated to the radio emission.

A LINK BETWEEN X-RAY EMISSION LINES AND RADIO JETS IN 4U 1630-47?

International Nuclear Information System (INIS)

Neilsen, Joseph; Coriat, Mickaël; Fender, Rob; Broderick, Jess W.; Lee, Julia C.; Ponti, Gabriele; Tzioumis, Anastasios K.; Edwards, Philip G.

2014-01-01

Recently, Díaz Trigo et al. reported an XMM-Newton detection of relativistically Doppler-shifted emission lines associated with steep-spectrum radio emission in the stellar-mass black hole candidate 4U 1630-47 during its 2012 outburst. They interpreted these lines as indicative of a baryonic jet launched by the accretion disk. Here we present a search for the same lines earlier in the same outburst using high-resolution X-ray spectra from the Chandra HETGS. While our observations (eight months prior to the XMM-Newton campaign) also coincide with detections of steep spectrum radio emission by the Australia Telescope Compact Array, we find no evidence for any relativistic X-ray emission lines. Indeed, despite ∼5 × brighter radio emission, our Chandra spectra allow us to place an upper limit on the flux in the blueshifted Fe XXVI line that is ≳ 20 × weaker than the line observed by Díaz Trigo et al. We explore several scenarios that could explain our differing results, including variations in the geometry of the jet or a mass-loading process or jet baryon content that evolves with the accretion state of the black hole. We also consider the possibility that the radio emission arises in an interaction between a jet and the nearby interstellar medium, in which case the X-ray emission lines might be unrelated to the radio emission

Study of SmS properties in the low pressure phase (black phase)

International Nuclear Information System (INIS)

Bordier, G.

1986-01-01

SmS was studied for the transition from low pressure phase (black phase) to high pressure phase with an intermediate valence. But the study of the black phase is very rich. The variations of electron transport properties with pressure at low temperature show a semi-metal phase located, in the pressure-temperature diagram in the black phase for pressure over 4 kbars, corresponding to the phase B'of the doping-temperature diagram. Electron spin resonance shows a lack of sulfur and nearby this defect a samarium ion, magnetically coupled with the matrix, presents a divalent trivalent transition. Resonance lines are broadened with temperature. Conductivity relaxations occur at low pressure and low temperature by trapping a conduction electron, by magnetic exchange giving a bounded magnetic polaron. The relaxation time at null magnetic field is activated. An approximation of trapping barrier and critical field corresponding the maximum magnetoresistance is given by a model [fr

A Link Between X-ray Emission Lines and Radio Jets in 4U 1630-47?

Science.gov (United States)

Neilsen, Joseph; Coriat, Mickaël; Fender, Rob; Lee, Julia C.; Ponti, Gabriele; Tzioumis, A.; Edwards, Phillip; Broderick, Jess

2014-06-01

Recently, Díaz Trigo et al. reported an XMM-Newton detection of relativistically Doppler-shifted emission lines associated with steep-spectrum radio emission in the stellar-mass black hole candidate 4U 1630-47 during its 2012 outburst. They interpreted these lines as indicative of a baryonic jet launched by the accretion disk. We present a search for the same lines earlier in the same outburst using high-resolution X-ray spectra from the Chandra HETGS. While our observations (eight months prior to the XMM-Newton campaign) also coincide with detections of steep spectrum radio emission by the Australia Telescope Compact Array, we find a strong disk wind but no evidence for any relativistic X-ray emission lines. Indeed, despite ˜5× brighter radio emission, our Chandra spectra allow us to place an upper limit on the flux in the blueshifted Fe XXVI line that is ˜20× weaker than the line observed by Díaz Trigo et al. Thus we can conclusively say that radio emission is not universally associated with relativistically Doppler-shifted emission lines in 4U 1630-47. We explore several scenarios that could explain our differing results, including variations in the geometry of the jet or a mass-loading process or jet baryon content that evolves with the accretion state of the black hole. We also consider the possibility that the radio emission arises in an interaction between a jet and the nearby ISM, in which case the X-ray emission lines might be unrelated to the radio emission.

Comparative genome and evolutionary analysis of naturally occurring Beilong virus in brown and black rats.

Science.gov (United States)

Woo, Patrick C Y; Wong, Annette Y P; Wong, Beatrice H L; Lam, Carol S F; Fan, Rachel Y Y; Lau, Susanna K P; Yuen, Kwok-Yung

2016-11-01

Recently, we reported the presence of Beilong virus in spleen and kidney samples of brown rats and black rats, suggesting that these rodents could be natural reservoirs of Beilong virus. In this study, four genomes of Beilong virus from brown rats and black rats were sequenced. Similar to the Beilong virus genome sequenced from kidney mesangial cell line culture, those of J-virus from house mouse and Tailam virus from Sikkim rats, these four genomes from naturally occurring Beilong virus also contain the eight genes (3'-N-P/V/C-M-F-SH-TM-G-L-5'). In these four genomes, the attachment glycoprotein encoded by the G gene consists of 1046 amino acids; but for the original Beilong virus genome sequenced from kidney mesangial cell line, the G CDS was predicted to be prematurely terminated at position 2205 (TGG→TAG), resulting in a 734-amino-acid truncated G protein. This phenomenon of a lack of nonsense mutation in naturally occurring Beilong viruses was confirmed by sequencing this region of 15 additional rodent samples. Phylogenetic analyses showed that the cell line and naturally occurring Beilong viruses were closely clustered, without separation into subgroups. In addition, these viruses were further clustered with J-virus and Tailam virus, with high bootstrap supports of >90%, forming a distinct group in Paramyxoviridae. Brown rats and black rats are natural reservoirs of Beilong virus. Our results also supports that the recently proposed genus, Jeilongvirus, should encompass Beilong virus, J-virus and Tailam virus as members. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Lumpy AdS5× S5 black holes and black belts

International Nuclear Information System (INIS)

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

2015-01-01

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

Black holes in binary stars

NARCIS (Netherlands)

Wijers, R.A.M.J.

1996-01-01

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

Models of black hole production at LHC

International Nuclear Information System (INIS)

Klippert, R.; Salinas, C. J. Solano

2002-01-01

The purpose of this paper is to discuss about the different models for black hole production at the future Large Hadron Collider. In traditional scenarios the Planck scale is fundamental, and the weak scale is derived from it via some dynamical mechanism. Recently, several authors are exploring an alternative viewpoint where the weak scale is the fundamental scale of nature and the 4-dimensional Planck scale is to be derived from that. These scenarios include large or warped extra dimensions, propagation of matter and gauge degrees of freedom on brane worlds, and a fundamental Planck scale of O(TeV). If the scale of quantum gravity is near TeV we will have a copious production of mini black holes at the Large Hadron Collider and Cosmic rays interactions in the atmosphere. We discussed as well other line of semi-classical models from analog gravity in nonlinear electrodynamics that can be tested as well at LHC. The possible consequences of these models for high energy experimental physics are discussed

Black Interpretation, Black American Literature, and Grey Audiences.

Science.gov (United States)

Washington, Earl M.

1981-01-01

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

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

Directory of Open Access Journals (Sweden)

Monique Moultrie

2017-11-01

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

to view fulltext PDF

Indian Academy of Sciences (India)

The solid line shows schematically the pressure-density relationship for cold matter. The dashed lines show the pressure PI1 needed to balance gravity in a body of mass M and radius R as a function of its density p. Intersection with the solid line is the condition for equilibrium P oc (GM. 2. ) / R 2 = GM 2 • Since p oc M/RJ ,.

Black holes. Chapter 6

International Nuclear Information System (INIS)

Penrose, R.

1980-01-01

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

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

International Nuclear Information System (INIS)

Kleihaus, Burkhard; Kunz, Jutta; Radu, Eugen

2015-01-01

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

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

Directory of Open Access Journals (Sweden)

Timothy van Aarde

2016-08-01

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

Black hole hair removal

International Nuclear Information System (INIS)

Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

2009-01-01

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

A geometric stochastic approach based on marked point processes for road mark detection from high resolution aerial images

Science.gov (United States)

Tournaire, O.; Paparoditis, N.

Road detection has been a topic of great interest in the photogrammetric and remote sensing communities since the end of the 70s. Many approaches dealing with various sensor resolutions, the nature of the scene or the wished accuracy of the extracted objects have been presented. This topic remains challenging today as the need for accurate and up-to-date data is becoming more and more important. Based on this context, we will study in this paper the road network from a particular point of view, focusing on road marks, and in particular dashed lines. Indeed, they are very useful clues, for evidence of a road, but also for tasks of a higher level. For instance, they can be used to enhance quality and to improve road databases. It is also possible to delineate the different circulation lanes, their width and functionality (speed limit, special lanes for buses or bicycles...). In this paper, we propose a new robust and accurate top-down approach for dashed line detection based on stochastic geometry. Our approach is automatic in the sense that no intervention from a human operator is necessary to initialise the algorithm or to track errors during the process. The core of our approach relies on defining geometric, radiometric and relational models for dashed lines objects. The model also has to deal with the interactions between the different objects making up a line, meaning that it introduces external knowledge taken from specifications. Our strategy is based on a stochastic method, and in particular marked point processes. Our goal is to find the objects configuration minimising an energy function made-up of a data attachment term measuring the consistency of the image with respect to the objects and a regularising term managing the relationship between neighbouring objects. To sample the energy function, we use Green algorithm's; coupled with a simulated annealing to find its minimum. Results from aerial images at various resolutions are presented showing that our

Tidal disruption of stars by supermassive black holes: The X-ray view

Directory of Open Access Journals (Sweden)

Komossa S.

2012-12-01

Full Text Available The tidal disruption of stars by supermassive black holes produces luminous soft X-ray accretion flares in otherwise inactive galaxies. First events have been discovered in X-rays with the ROSAT observatory, and have more recently been detected with XMM-Newton, Chandra and Swift, and at other wavelengths. In X-rays, they typically appear as very soft, exceptionally luminous outbursts of radiation, which decline consistent with L ∝ t−5/3 on the timescale of months to years. They reach total amplitudes of decline up to factors 1000–6000 more than a decade after their initial high-states, and in low-state, their host galaxies are essentially X-ray inactive, optically inactive, and radio inactive. X-ray luminous tidal disruption events (TDEs represent a powerful new probe of accretion physics near the event horizon, and of relativistic effects. TDEs offer a new way of estimating black hole spin, and they are signposts of supermassive binary black holes and recoiling black holes. Once discovered in the thousands in upcoming sky surveys, their rates will probe stellar dynamics in distant galaxies, and they will uncover the – so far elusive – population of intermediate mass black holes in the universe, if they do exist. Further, the reprocessing of the flare into IR, optical and UV emission lines provides us with multiple new diagnostics of the properties of any gaseous material in the vicinity of the black hole (including the disrupted star itself and in the host galaxy. First candidate events of this kind have been reported recently.

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

Science.gov (United States)

2016-12-01

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

A direct gravitational lensing test for 10 exp 6 solar masses black holes in halos of galaxies

Science.gov (United States)

Wambsganss, Joachim; Paczynski, Bohdan

1992-01-01

We propose a method that will be able to detect or exclude the existence of 10 exp 6 solar masses black holes in the halos of galaxies. VLBA radio maps of two milliarcsecond jets of a gravitationally lensed quasar will show the signature of these black holes - if they exist. If there are no compact objects in this mass range along the line of sight, the two jets should be linear mappings of each other. If they are not, there must be compact objects of about 10 exp 6 solar masses in the halo of the galaxy that deform the images by gravitational deflection. We present numerical simulations for the two jets A and B of the double quasar 0957 + 561, but the method is valid for any gravitationally lensed quasar with structure on milliarcsecond scales. As a by-product from high-quality VLBA maps of jets A and B, one will be able to tell which features in the maps are intrinsic in the original jet and which are only an optical illusion, i.e., gravitational distortions by black holes along the line of sight.

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

African Journals Online (AJOL)

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

Weight loss in individuals with metabolic syndrome given DASH diet counseling when provided a low sodium vegetable juice: a randomized controlled trial.

Science.gov (United States)

Shenoy, Sonia F; Poston, Walker Sc; Reeves, Rebecca S; Kazaks, Alexandra G; Holt, Roberta R; Keen, Carl L; Chen, Hsin Ju; Haddock, C Keith; Winters, Barbara L; Khoo, Chor San H; Foreyt, John P

2010-02-23

Metabolic syndrome, a constellation of metabolic risk factors for type 2 diabetes and cardiovascular disease, is one of the fastest growing disease entities in the world. Weight loss is thought to be a key to improving all aspects of metabolic syndrome. Research studies have suggested benefits from diets rich in vegetables and fruits in helping individuals reach and achieve healthy weights. To evaluate the effects of a ready to serve vegetable juice as part of a calorie-appropriate Dietary Approaches to Stop Hypertension (DASH) diet in an ethnically diverse population of people with Metabolic Syndrome on weight loss and their ability to meet vegetable intake recommendations, and on their clinical characteristics of metabolic syndrome (waist circumference, triglycerides, HDL, fasting blood glucose and blood pressure).A secondary goal was to examine the impact of the vegetable juice on associated parameters, including leptin, vascular adhesion markers, and markers of the oxidative defense system and of oxidative stress. A prospective 12 week, 3 group (0, 8, or 16 fluid ounces of low sodium vegetable juice) parallel arm randomized controlled trial. Participants were requested to limit their calorie intake to 1600 kcals for women and 1800 kcals for men and were educated on the DASH diet. A total of 81 (22 men & 59 women) participants with Metabolic Syndrome were enrolled into the study. Dietary nutrient and vegetable intake, weight, height, leptin, metabolic syndrome clinical characteristics and related markers of endothelial and cardiovascular health were measured at baseline, 6-, and 12-weeks. There were significant group by time interactions when aggregating both groups consuming vegetable juice (8 or 16 fluid ounces daily). Those consuming juice lost more weight, consumed more Vitamin C, potassium, and dietary vegetables than individuals who were in the group that only received diet counseling (p juice into the daily diet can be a simple and effective way to

Weight loss in individuals with metabolic syndrome given DASH diet counseling when provided a low sodium vegetable juice: a randomized controlled trial

Directory of Open Access Journals (Sweden)

Chen Hsin

2010-02-01

Full Text Available Abstract Background Metabolic syndrome, a constellation of metabolic risk factors for type 2 diabetes and cardiovascular disease, is one of the fastest growing disease entities in the world. Weight loss is thought to be a key to improving all aspects of metabolic syndrome. Research studies have suggested benefits from diets rich in vegetables and fruits in helping individuals reach and achieve healthy weights. Objective To evaluate the effects of a ready to serve vegetable juice as part of a calorie-appropriate Dietary Approaches to Stop Hypertension (DASH diet in an ethnically diverse population of people with Metabolic Syndrome on weight loss and their ability to meet vegetable intake recommendations, and on their clinical characteristics of metabolic syndrome (waist circumference, triglycerides, HDL, fasting blood glucose and blood pressure. A secondary goal was to examine the impact of the vegetable juice on associated parameters, including leptin, vascular adhesion markers, and markers of the oxidative defense system and of oxidative stress. Methods A prospective 12 week, 3 group (0, 8, or 16 fluid ounces of low sodium vegetable juice parallel arm randomized controlled trial. Participants were requested to limit their calorie intake to 1600 kcals for women and 1800 kcals for men and were educated on the DASH diet. A total of 81 (22 men & 59 women participants with Metabolic Syndrome were enrolled into the study. Dietary nutrient and vegetable intake, weight, height, leptin, metabolic syndrome clinical characteristics and related markers of endothelial and cardiovascular health were measured at baseline, 6-, and 12-weeks. Results There were significant group by time interactions when aggregating both groups consuming vegetable juice (8 or 16 fluid ounces daily. Those consuming juice lost more weight, consumed more Vitamin C, potassium, and dietary vegetables than individuals who were in the group that only received diet counseling (p

Black Tea

Science.gov (United States)

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

Properties of Narrow line Seyfert 1 galaxies

Science.gov (United States)

Rakshit, Suvendu; Stalin, Chelliah Subramonian; Chand, Hum; Zhang, Xue-Guang

2018-04-01

Narrow line Seyfert 1 (NLSy1) galaxies constitute a class of active galactic nuclei characterized by the full width at half maximum (FWHM) of the Hα broad emission line 10 pixel-1. A strong correlation between the Hα and Hα emission lines is found both in the FWHM and flux. The nuclear continuum luminosity is found to be strongly correlated with the luminosity of Hα, Hα and [O III] emission lines. The black hole mass in NLSy1 galaxies is lower compared to their broad line counterparts. Compared to BLSy1 galaxies, NLSy1 galaxies have a stronger FeII emission and a higher Eddington ratio that place them in the extreme upper right corner of the R4570 - λEdd diagram. The distribution of the radio-loudness parameter (R) in NLSy1 galaxies drops rapidly at R>10 compared to the BLSy1 galaxies that have powerful radio jets. The soft X-ray photon index in NLSy1 galaxies is on average higher (2.9 ± 0.9) than BLSy1 galaxies (2.4 ± 0.8). It is anti-correlated with the Hα width but correlated with the FeII strength. NLSy1 galaxies on average have a lower amplitude of optical variability compared to their broad lines counterparts. These results suggest Eddington ratio as the main parameter that drives optical variability in these sources.

Failed Radiatively Accelerated Dusty Outflow Model of the Broad Line Region in Active Galactic Nuclei. I. Analytical Solution

Energy Technology Data Exchange (ETDEWEB)

Czerny, B.; Panda, S.; Wildy, C.; Sniegowska, M. [Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland); Li, Yan-Rong; Wang, J.-M. [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquan Road, Beijing 100049 (China); Hryniewicz, K.; Sredzinska, J. [Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, 00-716 Warsaw (Poland); Karas, V., E-mail: bcz@cft.edu.pl [Astronomical Institute, Academy of Sciences, Bocni II 1401, CZ-141 00 Prague (Czech Republic)

2017-09-10

The physical origin of the broad line region in active galactic nuclei is still unclear despite many years of observational studies. The reason is that the region is unresolved, and the reverberation mapping results imply a complex velocity field. We adopt a theory-motivated approach to identify the principal mechanism responsible for this complex phenomenon. We consider the possibility that the role of dust is essential. We assume that the local radiation pressure acting on the dust in the accretion disk atmosphere launches the outflow of material, but higher above the disk the irradiation from the central parts causes dust evaporation and a subsequent fallback. This failed radiatively accelerated dusty outflow is expected to represent the material forming low ionization lines. In this paper we formulate simple analytical equations to describe the cloud motion, including the evaporation phase. The model is fully described just by the basic parameters of black hole mass, accretion rate, black hole spin, and viewing angle. We study how the spectral line generic profiles correspond to this dynamic. We show that the virial factor calculated from our model strongly depends on the black hole mass in the case of enhanced dust opacity, and thus it then correlates with the line width. This could explain why the virial factor measured in galaxies with pseudobulges differs from that obtained from objects with classical bulges, although the trend predicted by the current version of the model is opposite to the observed trend.

Ao38, a new cell line from eggs of the black witch moth, Ascalapha odorata (Lepidoptera: Noctuidae, is permissive for AcMNPV infection and produces high levels of recombinant proteins

Directory of Open Access Journals (Sweden)

Zhang Sheng

2010-07-01

Full Text Available Abstract Background The insect cell line is a critical component in the production of recombinant proteins in the baculovirus expression system and new cell lines hold the promise of increasing both quantity and quality of protein production. Results Seventy cell lines were established by single-cell cloning from a primary culture of cells derived from eggs of the black witch moth (Ascalapha odorata; Lepidoptera, Noctuidae. Among 8 rapidly growing lines, cell line 38 (Ao38 was selected for further analysis, based on susceptibility to AcMNPV infection and production of secreted alkaline phosphatase (SEAP from a baculovirus expression vector. In comparisons with low-passage High Five (BTI-Tn-5B1-4 cells, infected Ao38 cells produced β-galactosidase and SEAP at levels higher (153% and 150%, respectively than those measured from High Five cells. Analysis of N-glycans of SEAP produced in Ao38 cells revealed two N-glycosylation sites and glycosylation patterns similar to those reported for High Five and Sf9 cells. Glycopeptide isoforms consisted of pauci- or oligomannose, with and without fucose on N-acetylglucosamine(s linked to asparagine residues. Estimates of Ao38 cell volume suggest that Ao38 cells are approximately 2.5× larger than Sf9 cells but only approximately 74% of the size of High Five cells. Ao38 cells were highly susceptible to AcMNPV infection, similar to infectivity of Sf9 cells. Production of infectious AcMNPV budded virions from Ao38 cells peaked at approximately 4.5 × 107 IU/ml, exceeding that from High Five cells while lower than that from Sf9 cells. Ao38 cells grew rapidly in stationary culture with a population doubling time of 20.2 hr, and Ao38 cells were readily adapted to serum-free medium (Sf-900III and to a suspension culture system. Analysis of Ao38 and a parental Ascalapha odorata cell line indicated that these lines were free of the alphanodavirus that was recently identified as an adventitious agent in High Five cell

Study of the low pressure (Black Phase) SmS properties

International Nuclear Information System (INIS)

Bordier, G.

1987-03-01

SmS has been studied for its transition from the low pressure black phase to the high pressure intermediate valence phase; but the black phase properties seem to be very rich. The variations which pressure of the low-temperature electronic transport properties show the existence of a semi-metallic phase within the black phase domain in a pressure-temperature diagram, for a pressure above 4 kbar, which corresponds to the so-called B'phase. We study the insulating low pressure phase with a model involving acceptor like states. Using electronic paramagnetic resonance experiments we observe a square symmetry trivalent samarium ion neighbour of a sulfure defect, and magnetically coupled with the lattice. This defect exists in two nearly symmetric configurations and the resonance line broadens with temperature in an actived way. It gives rise to metastable effects yielding conductivity relaxations, analysed with stretched exponential laws, because the defect traps magnetically conduction electrons forming a bound magnetic polaron. The relaxation time at zero field is temperature actived. We develop a phenomenological model that gives the good orders of magnitude for the trapping barrier and for the critical field corresponding to the maximum of the low temperature magnetoresistance [fr

Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database

DEFF Research Database (Denmark)

Peterson, B. M.; Ferrarese, L.; Gilbert, K. M.

2004-01-01

We present improved black hole masses for 35 active galactic nuclei (AGNs) based on a complete and consistent reanalysis of broad emission-line reverberation-mapping data. From objects with multiple line measurements, we find that the highest precision measure of the virial product is obtained...

Black holes are warm

International Nuclear Information System (INIS)

Ravndal, F.

1978-01-01

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

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

Science.gov (United States)

Maylor, Uvanney

2009-01-01

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

ANALISIS GERAK ROBOT LINE TRACER DENGAN PROGRAM ARTIFICIAL INTELLEGENCE MENGGUNAKAN MICROCONTROLLER AT89S51

OpenAIRE

I Wayan Widhiada

2012-01-01

The research discussed about the work system of The Line Tracer Robot movement analysis, with using the AI program and assembler programming language. The tools that used are microcontroller type AT89S51, Meitan ASM 2005 Standard Edition version 1.00 as development tools and Meitan 2005 as the hardware tools modul. From the result of research, it can be known that The Line Tracer Robot with AI program is able to show differences, among the white as a based colour and black as a line colour. T...

Effect of layer stacking and p-type doping on the performance of InAs/InP quantum-dash-in-a-well lasers emitting at 1.55 μm

International Nuclear Information System (INIS)

Moreau, G.; Azouigui, S.; Cong, D.-Y.; Merghem, K.; Martinez, A.; Patriarche, G.; Ramdane, A.; Lelarge, F.; Rousseau, B.; Dagens, B.; Poingt, F.; Accard, A.; Pommereau, F.

2006-01-01

The authors report the growth of 6-, 9-, and 12-layer InAs/InP quantum-dash-in-a-well (DWELL) laser structures using gas source molecular beam epitaxy. Broad area laser performance has been investigated as a function of number of layers. The highest modal gain at 48 cm -1 is achieved for an optimized nine-DWELL layer structure. The effect of layer stacking and p-type doping on the characteristic temperature is also reported. Nine-DWELL layer single mode ridge waveguide lasers showed high slope efficiency (0.2 W/A per facet) and output power (P out =20 mW), close to those of conventional quantum well devices

Sifting for Success: A Grounded Theory Approach to Sponsorship of Black Student Academic Success

Science.gov (United States)

Powell, Shameka N.

2015-01-01

Numerous findings and theories have been used to make sense of African Americans students' educational successes and experiences. Along those lines, the purpose of this study is to generate a theoretical framework of sponsorship that is grounded in Black students' educational experiences. Sponsorship is taken to be the process through which agents…

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...

HIGH JET EFFICIENCY AND SIMULATIONS OF BLACK HOLE MAGNETOSPHERES

International Nuclear Information System (INIS)

Punsly, Brian

2011-01-01

This Letter reports on a growing body of observational evidence that many powerful lobe-dominated (FR II) radio sources likely have jets with high efficiency. This study extends the maximum efficiency line (jet power ∼25 times the thermal luminosity) defined in Fernandes et al. so as to span four decades of jet power. The fact that this line extends over the full span of FR II radio power is a strong indication that this is a fundamental property of jet production that is independent of accretion power. This is a valuable constraint for theorists. For example, the currently popular 'no-net-flux' numerical models of black hole accretion produce jets that are two to three orders of magnitude too weak to be consistent with sources near maximum efficiency.

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.

Baryons in the relativistic jets of the stellar-mass black-hole candidate 4U 1630-47.

Science.gov (United States)

Trigo, María Díaz; Miller-Jones, James C A; Migliari, Simone; Broderick, Jess W; Tzioumis, Tasso

2013-12-12

Accreting black holes are known to power relativistic jets, both in stellar-mass binary systems and at the centres of galaxies. The power carried away by the jets, and, hence, the feedback they provide to their surroundings, depends strongly on their composition. Jets containing a baryonic component should carry significantly more energy than electron-positron jets. Energetic considerations and circular-polarization measurements have provided conflicting circumstantial evidence for the presence or absence of baryons in jets, and the only system in which they have been unequivocally detected is the peculiar X-ray binary SS 433 (refs 4, 5). Here we report the detection of Doppler-shifted X-ray emission lines from a more typical black-hole candidate X-ray binary, 4U 1630-47, coincident with the reappearance of radio emission from the jets of the source. We argue that these lines arise from baryonic matter in a jet travelling at approximately two-thirds the speed of light, thereby establishing the presence of baryons in the jet. Such baryonic jets are more likely to be powered by the accretion disk than by the spin of the black hole, and if the baryons can be accelerated to relativistic speeds, the jets should be strong sources of γ-rays and neutrino emission.

Q-Φ criticality in the extended phase space of (n + 1)-dimensional RN-AdS black holes

Energy Technology Data Exchange (ETDEWEB)

Ma, Yu-Bo [Beijing Normal University, Department of Astronomy, Beijing (China); Shanxi Datong University, School of Physics, Datong (China); Zhao, Ren [Shanxi Datong University, School of Physics, Datong (China); Cao, Shuo [Beijing Normal University, Department of Astronomy, Beijing (China)

2016-12-15

In order to achieve a deeper understanding of gravity theories, i.e., the quantum properties of gravity theories and the statistical explanation of gravitational entropy, it is important to further investigate the thermodynamic properties of a black hole at the critical point, besides the phase transition and critical behaviors. In this paper, by using Maxwell's equal area law, we choose T, Q, Φ as the state parameters and study the phase equilibrium problem of a general (n + 1)-dimensional RN-AdS black holes thermodynamic system. The boundary of the two-phase coexistence region and its isotherm and isopotential lines are presented, which may provide a theoretical foundation for studying the phase transition and phase structure of black hole systems. (orig.)

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

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…

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

International Nuclear Information System (INIS)

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

2006-01-01

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

CONSTRAINTS ON COMPTON-THICK WINDS FROM BLACK HOLE ACCRETION DISKS: CAN WE SEE THE INNER DISK?

International Nuclear Information System (INIS)

Reynolds, Christopher S.

2012-01-01

Strong evidence is emerging that winds can be driven from the central regions of accretion disks in both active galactic nuclei and Galactic black hole binaries. Direct evidence for highly ionized, Compton-thin inner-disk winds comes from observations of blueshifted (v ∼ 0.05-0.1c) iron-K X-ray absorption lines. However, it has been suggested that the inner regions of black hole accretion disks can also drive Compton-thick winds—such winds would enshroud the inner disk, preventing us from seeing direct signatures of the accretion disk (i.e., the photospheric thermal emission, or the Doppler/gravitationally broadened iron Kα line). Here, we show that, provided the source is sub-Eddington, the well-established wind-driving mechanisms fail to launch a Compton-thick wind from the inner disk. For the accelerated region of the wind to be Compton-thick, the momentum carried in the wind must exceed the available photon momentum by a factor of at least 2/λ, where λ is the Eddington ratio of the source, ruling out radiative acceleration unless the source is very close to the Eddington limit. Compton-thick winds also carry large mass fluxes, and a consideration of the connections between the wind and the disk shows this to be incompatible with magneto-centrifugal driving. Finally, thermal driving of the wind is ruled out on the basis of the large Compton radii that typify black hole systems. In the absence of some new acceleration mechanisms, we conclude that the inner regions of sub-Eddington accretion disks around black holes are indeed naked.

BlackBerry For Dummies

CERN Document Server

Kao, Robert

2010-01-01

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

The Supermassive Black Hole—Galaxy Connection

Science.gov (United States)

King, Andrew

2014-09-01

The observed scaling relations imply that supermassive black holes (SMBH) and their host galaxies evolve together. Near-Eddington winds from the SMBH accretion discs explain many aspects of this connection. The wind Eddington factor should be in the range ˜1-30. A factor give black hole winds with velocities v˜0.1 c, observable in X-rays, just as seen in the most extreme ultrafast outflows (UFOs). Higher Eddington factors predict slower and less ionized winds, observable in the UV, as in BAL QSOs. In all cases the wind must shock against the host interstellar gas and it is plausible that these shocks should cool efficiently. There is detailed observational evidence for this in some UFOs. The wind sweeps up the interstellar gas into a thin shell and propels it outwards. For SMBH masses below a certain critical ( M- σ) value, all these outflows eventually stall and fall back, as the Eddington thrust of the wind is too weak to drive the gas to large radii. But once the SMBH mass reaches the critical M- σ value the global character of the outflow changes completely. The wind shock is no longer efficiently cooled, and the resulting thermal expansion drives the interstellar gas far from the black hole, which is unlikely to grow significantly further. Simple estimates of the maximum stellar bulge mass M b allowed by self-limited star formation show that the SMBH mass is typically about 10-3 M b at this point, in line with observation. The expansion-driven outflow reaches speeds v out≃1200 km s-1 and drives rates in cool (molecular) gas, giving a typical outflow mechanical energy L mech≃0.05 L Edd, where L Edd is the Eddington luminosity of the central SMBH. This is again in line with observation. These massive outflows may be what makes galaxies become red and dead, and can have several other potentially observable effects. In particular they have the right properties to enrich the intergalactic gas with metals. Our current picture of SMBH-galaxy coevolution is

Black Hole Area Quantization rule from Black Hole Mass Fluctuations

OpenAIRE

Schiffer, Marcelo

2016-01-01

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

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

Science.gov (United States)

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

2014-01-01

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

Can we improve C IV-based single epoch black hole mass estimations?

Science.gov (United States)

Mejía-Restrepo, J. E.; Trakhtenbrot, B.; Lira, P.; Netzer, H.

2018-05-01

In large optical surveys at high redshifts (z > 2), the C IV broad emission line is the most practical alternative to estimate the mass (MBH) of active super-massive black holes (SMBHs). However, mass determinations obtained with this line are known to be highly uncertain. In this work we use the Sloan Digital Sky Survey Data Release 7 and 12 quasar catalogues to statistically test three alternative methods put forward in the literature to improve C IV-based MBH estimations. These methods are constructed from correlations between the ratio of the C IV line-width to the low ionization line-widths (Hα, Hβ and Mg II) and several other properties of rest-frame UV emission lines. Our analysis suggests that these correction methods are of limited applicability, mostly because all of them depend on correlations that are driven by the linewidth of the C IV profile itself and not by an interconnection between the linewidth of the C IV line with the linewidth of the low ionization lines. Our results show that optical C IV-based mass estimates at high redshift cannot be a proper replacement for estimates based on IR spectroscopy of low ionization lines like Hα, Hβ and Mg II.

Cr(VI) retention and transport through Fe(III)-coated natural zeolite

Energy Technology Data Exchange (ETDEWEB)

Du, Gaoxiang [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Li, Zhaohui, E-mail: li@uwp.edu [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144 (United States); Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China); Liao, Libing [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Hanson, Renee; Leick, Samantha; Hoeppner, Nicole [Geosciences Department, University of Wisconsin-Parkside, Kenosha, WI 53144 (United States); Jiang, Wei-Teh [Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan (China)

2012-06-30

Graphical abstract: Breakthrough curves of Cr(VI) from columns packed with raw zeolite (a) and Fe(III)-zeolite (b). The solid line in (b) is the HYDRUS-1D fit to the observed data with adsorption term only, while the dashed line in (b) includes a reduction term in the HYDRUS-1D fit. Highlights: Black-Right-Pointing-Pointer Zeolite modified with Fe(III) could be used for adsorption and retention of Cr(VI). Black-Right-Pointing-Pointer The Fe present on zeolite was in an amorphous Fe(OH){sub 3} form. Black-Right-Pointing-Pointer A Cr(VI) adsorption capacity of 82 mg/kg was found on Fe(III)-zeolite. Black-Right-Pointing-Pointer A Cr(VI) retardation factor of 3 or 5 was determined from column and batch studies. - Abstract: Cr(VI) is a group A chemical based on the weight of evidence of carcinogenicity. Its transport and retention in soils and groundwater have been studied extensively. Zeolite is a major component in deposits originated from volcanic ash and tuff after alteration. In this study, zeolite aggregates with the particle size of 1.4-2.4 mm were preloaded with Fe(III). The influence of present Fe(III) on Cr(VI) retention by and transport through zeolite was studied under batch and column experiments. The added Fe(III) resulted in an enhanced Cr(VI) retention by the zeolite with a capacity of 82 mg/kg. The Cr(VI) adsorption on Fe(III)-zeolite followed a pseudo-second order kinetically and the Freundlich adsorption isotherm thermodynamically. Fitting the column experimental data to HYDRUS-1D resulted in a retardation factor of 3 in comparison to 5 calculated from batch tests at an initial Cr(VI) concentration of 3 mg/L. The results from this study showed that enhanced adsorption and retention of Cr(VI) may happen in soils derived from volcanic ash and tuff that contains significant amounts of zeolite with extensive Fe(III) coating.

The Black Family as Educator.

Science.gov (United States)

Wallace, Joan

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

Monopole Black Hole Skyrmions

OpenAIRE

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

2000-01-01

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

Circular geodesic of Bardeen and Ayon-Beato-Garcia regular black-hole and no-horizon spacetimes

Science.gov (United States)

Stuchlík, Zdeněk; Schee, Jan

2015-12-01

In this paper, we study circular geodesic motion of test particles and photons in the Bardeen and Ayon-Beato-Garcia (ABG) geometry describing spherically symmetric regular black-hole or no-horizon spacetimes. While the Bardeen geometry is not exact solution of Einstein's equations, the ABG spacetime is related to self-gravitating charged sources governed by Einstein's gravity and nonlinear electrodynamics. They both are characterized by the mass parameter m and the charge parameter g. We demonstrate that in similarity to the Reissner-Nordstrom (RN) naked singularity spacetimes an antigravity static sphere should exist in all the no-horizon Bardeen and ABG solutions that can be surrounded by a Keplerian accretion disc. However, contrary to the RN naked singularity spacetimes, the ABG no-horizon spacetimes with parameter g/m > 2 can contain also an additional inner Keplerian disc hidden under the static antigravity sphere. Properties of the geodesic structure are reflected by simple observationally relevant optical phenomena. We give silhouette of the regular black-hole and no-horizon spacetimes, and profiled spectral lines generated by Keplerian rings radiating at a fixed frequency and located in strong gravity region at or nearby the marginally stable circular geodesics. We demonstrate that the profiled spectral lines related to the regular black-holes are qualitatively similar to those of the Schwarzschild black-holes, giving only small quantitative differences. On the other hand, the regular no-horizon spacetimes give clear qualitative signatures of their presence while compared to the Schwarschild spacetimes. Moreover, it is possible to distinguish the Bardeen and ABG no-horizon spacetimes, if the inclination angle to the observer is known.

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-12-15

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

Statistical black-hole thermodynamics

International Nuclear Information System (INIS)

Bekenstein, J.D.

1975-01-01

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

CO-Dark Star Formation and Black Hole Activity in 3C 368 at z = 1.131: Coeval Growth of Stellar and Supermassive Black Hole Masses

Energy Technology Data Exchange (ETDEWEB)

Lamarche, C.; Stacey, G.; Riechers, D.; Vishwas, A. [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States); Brisbin, D. [Núcleo de Astronomía, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Avenida Ejército 441, 8370191 Santiago (Chile); Ferkinhoff, C. [Department of Physics, Winona State University, Winona, MN, 55987 (United States); Hailey-Dunsheath, S. [California Institute of Technology, Mail Code 301-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Nikola, T.; Spoon, H. [Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14853 (United States); Sharon, C. E., E-mail: cjl272@cornell.edu [Department of Physics and Astronomy, McMaster University, 1280 Main Street West, Hamilton, ON L85-4M1 (Canada)

2017-02-10

We present the detection of four far-infrared fine-structure oxygen lines, as well as strong upper limits for the CO(2–1) and [N ii] 205 μ m lines, in 3C 368, a well-studied radio-loud galaxy at z = 1.131. These new oxygen lines, taken in conjunction with previously observed neon and carbon fine-structure lines, suggest a powerful active galactic nucleus (AGN), accompanied by vigorous and extended star formation. A starburst dominated by O8 stars, with an age of ∼6.5 Myr, provides a good fit to the fine-structure line data. This estimated age of the starburst makes it nearly concurrent with the latest episode of AGN activity, suggesting a link between the growth of the supermassive black hole and stellar population in this source. We do not detect the CO(2–1) line, down to a level twelve times lower than the expected value for star-forming galaxies. This lack of CO line emission is consistent with recent star formation activity if the star-forming molecular gas has low metallicity, is highly fractionated (such that CO is photodissociated throughout much of the clouds), or is chemically very young (such that CO has not yet had time to form). It is also possible, although we argue it is unlikely, that the ensemble of fine-structure lines is emitted from the region heated by the AGN.

Bioactivities of anastasia black (Russian sweet pepper).

Science.gov (United States)

Shirataki, Yoshiaki; Kawase, Masami; Sakagami, Hiroshi; Nakashima, Hideki; Tani, Satoru; Tanaka, Toru; Sohara, Yoshitaka; Schelz, Zsuzsanna; Molnar, Joseph; Motohashi, Noboru

2005-01-01

Anastasia Black (Russian sweet pepper) of Capsicum annuum L. var. angulosum Mill. (Solanaceae) was successively extracted with hexane, acetone, methanol and 70% methanol, and the extracts were further separated into a total of twenty-three fractions by silica gel or octadecylsilane (ODS; C18) column chromatography. These extracts and fractions were investigated for their cytotoxicity, anti-human immunodeficiency virus (HIV), anti-Helicobacter pylori (H. pylori), urease inhibition and multidrug resistance (MDR) reversal activity. Some fractions of hexane and acetone extracts showed higher cytotoxic activity against three human oral tumor cell lines (squamous cell carcinoma HSC-2, HSC-3, submandibular gland carcinoma HSG) than against three normal human oral cells (gingival fibroblast HGF, pulp cell HPC, periodontal ligament fibroblast HPLF), suggesting a tumor-specific cytotoxic activity. No fractions displayed anti-HIV activity, but some hydrophobic fractions showed higher anti-H. pylori activity, urease inhibition activity and MDR reversal activity. The higher MDR activity of these fractions against MDR gene-transfected L5178 mouse lymphoma T cells may possibly be due to their higher content of carotene or polyphenol. These data suggest that Anastasia Black should be further investigated as a potent supplement for cancer chemotherapy.

Black holes without firewalls

Science.gov (United States)

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

2013-05-01

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

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

Science.gov (United States)

Story, Kaila Adia

2017-10-02

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

Subsurface geology of the upper Devonian-lower Mississippian black-shale sequence in eastern Kentucky

International Nuclear Information System (INIS)

Dillman, S.B.

1980-01-01

The Upper Devonian-Lower Mississippi black-shale sequence is an important source of natural gas in eastern Kentucky and with technological advances may be an important source of synthetic oil and uranium on the flanks of the Cincinnati arch. To enhance the understanding and development of these resources in the black-shale sequence, eight isopach maps, eight structure-contour maps and nine isopach maps of highly radioactive black shale were constructed. Structural features including the Rome trough, Rockcastle River uplift, Pine Mountain thrust fault, Kentucky River and Paint Creek fault zones and unnamed basinal areas in Greenup, Pike, and Knott counties were identified on the maps. Faults bounding the Rome trough and other structures were active intermittently throughout Late Devonian time. Other structures show only post-Devonian activity, whereas some show both Devonian and post-Devonian activity. Comparison of structure-contour and isopach maps allow the differentiation of syn- and post-sedimentray structural activity relative to the black-shale sequence. A north-south trending hinge line separates a broad platform area from an area of rapid eastward thickening into the Appalachian basin. Units 7 through 1 progressively onlap the Cincinnati arch; units 4 through 1 cover the arch

An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30.

Science.gov (United States)

Wu, Xue-Bing; Wang, Feige; Fan, Xiaohui; Yi, Weimin; Zuo, Wenwen; Bian, Fuyan; Jiang, Linhua; McGreer, Ian D; Wang, Ran; Yang, Jinyi; Yang, Qian; Thompson, David; Beletsky, Yuri

2015-02-26

So far, roughly 40 quasars with redshifts greater than z = 6 have been discovered. Each quasar contains a black hole with a mass of about one billion solar masses (10(9) M Sun symbol). The existence of such black holes when the Universe was less than one billion years old presents substantial challenges to theories of the formation and growth of black holes and the coevolution of black holes and galaxies. Here we report the discovery of an ultraluminous quasar, SDSS J010013.02+280225.8, at redshift z = 6.30. It has an optical and near-infrared luminosity a few times greater than those of previously known z > 6 quasars. On the basis of the deep absorption trough on the blue side of the Lyman-α emission line in the spectrum, we estimate the proper size of the ionized proximity zone associated with the quasar to be about 26 million light years, larger than found with other z > 6.1 quasars with lower luminosities. We estimate (on the basis of a near-infrared spectrum) that the black hole has a mass of ∼1.2 × 10(10) M Sun symbol, which is consistent with the 1.3 × 10(10) M Sun symbol derived by assuming an Eddington-limited accretion rate.

Establishment of a human cell line stably overexpressing mouse Nip45 and characterization of Nip45 subcellular localization

Energy Technology Data Exchange (ETDEWEB)

Hashiguchi, Kohtaro; Ozaki, Masumi [Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kumamoto (Japan); Kuraoka, Isao [Biological Chemistry Group, Division of Chemistry, Graduate School of Engineering Science, Osaka University, Osaka (Japan); Saitoh, Hisato, E-mail: hisa@kumamoto-u.ac.jp [Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kumamoto (Japan); Department of New Frontier Sciences, Graduate School of Science and Technology, Kumamoto University, Kumamoto (Japan); Global COE (Centers of Excellence) Program, Global Initiative Center for Pulsed Power Engineering, Kumamoto University, Kumamoto (Japan)

2013-01-04

Highlights: Black-Right-Pointing-Pointer A human cell line expressing a mouse Nip45 has facilitated Nip45 analysis. Black-Right-Pointing-Pointer Nip45 does not effectively inhibit polySUMOylation in vivo. Black-Right-Pointing-Pointer Nip45 interacts directly with SUMO and SUMO chains. Black-Right-Pointing-Pointer Nip45 accumulates at PML bodies in response to proteasome inhibition. -- Abstract: The nuclear factor of activated T cells, cytoplasmic, calcineurin dependent 2 interacting protein, Nfatc2ip (Nip45), has been implicated as a crucial coordinator of the immune response and of cellular differentiation in humans and mice, and contains SUMO-like domains in its C-terminal region. However, the significance of its N-terminal region and its correlation to the SUMO modification pathway remain largely uncharacterized. In this study, a human cultured cell line was established, in which FLAG-tagged mouse Nip45 (FLAG-mNip45) was stably overexpressed. Under standard, non-stressful conditions, we detected FLAG-mNip45 diffusely distributed in the nucleus. Intriguingly, proteasome inhibition by MG132 caused FLAG-mNip45, together with SUMOylated proteins, to localize in nuclear domains associated with promyelocytic leukemia protein. Finally, using an in vitro binding assay, we showed interaction of the N-terminal region of mNip45 with both free SUMO-3 and SUMO-3 chains, indicating that Nip45 may, in part, exert its function via interaction with SUMO/SUMOylated proteins. Taken together, our study provides novel information on a poorly characterized mammalian protein and suggests that our newly established cell line will be useful for elucidating the physiological role of Nip45.

Computerization of administration and operation management in Polish black coal mines

Energy Technology Data Exchange (ETDEWEB)

Mastej, R.; Syrkiewicz, J. (Centralny Osrodek Informatyki Gornictwa (Poland))

1990-08-01

Characterizes main solutions of the computerized management model adopted in Poland for the mining industry and the technical and oganizational structure of computer system application. Computer systems for black coal mines and the range of microprocessor application are shown in block diagrams. The COIG mining information center makes about 45 computer system modules with independent implementation available for black coal mines. The general concept foresees central data processing in the COIG center on the ODRA 1305 and ICL 297 computers with the G-3 operating system in the first stage and an ICL series 39 computer with the VME operating system in the second stage. For mines where no transmission lines are available local solutions based on smaller ICL computers, minicomputers or computer networks with the NOVELL network operating system or multi-access systems with the UNIX operating system are planned. 3 refs.

A minority research and education information service: Design, develop, pilot test, and implement on-line access for historically black colleges and universities and government agencies. Annual status report, September 28, 1992--September 27, 1993

Energy Technology Data Exchange (ETDEWEB)

Rodman, J.A.

1993-08-01

The goal of the MOLIS project was to develop, design, and pilot test on-line access to current information on minority colleges and universities as well as federal minority opportunities. Federal Information Exchange, Inc. (FIE), a diversified information services company recognized by researchers and educators as a leader in the field of information delivery services, was awarded a 5 year small business research grant to develop and implement MOLIS. Since going on-line on April 29, 1991, MOLIS has provided current information on 138 Black and Hispanic colleges and universities -- including faculty and student profiles, financial data, research centers and equipment information, precollege and education programs, emerging capabilities, enrollment data, administrative personnel data, and current events -- as well as minority opportunities from participating federal agencies. Six federal agencies are currently participating in MOLIS, including: Agency for International Development; Department of Commerce; Department of Energy; Department of Housing and Urban Development; National Aeronautics and Space Administration; and National Science Foundation.

Personality and behavior prediction and consistency across cultures: A multimethod study of Blacks and Whites in South Africa.

Science.gov (United States)

Fetvadjiev, Velichko H; Meiring, Deon; van de Vijver, Fons J R; Nel, J Alewyn; Sekaja, Lusanda; Laher, Sumaya

2018-03-01

The cross-cultural universality of behavior's consistency and predictability from personality, assumed in trait models though challenged in cultural psychological models, has usually been operationalized in terms of beliefs and perceptions, and assessed using single-instance self-reports. In a multimethod study of actual behavior across a range of situations, we examined predictability and consistency in participants from the more collectivistic Black ethnic group and the more individualistic White group in South Africa. Participants completed personality questionnaires before the behavior measurements. In Study 1, 107 Black and 241 White students kept diaries for 21 days, recording their behaviors and the situations in which they had occurred. In Study 2, 57 Black and 52 White students were video-recorded in 12 situations in laboratory settings, and external observers scored their behaviors. Across both studies, behavior was predicted by personality on average equally well in the 2 groups, and equally well when using trait-adjective- and behavior-based personality measures. The few cultural differences in situational variability were not in line with individualism-collectivism; however, subjective perceptions of variability, operationalized as dialectical beliefs, were more in line with individualism-collectivism: Blacks viewed their behavior as more variable than Whites. We propose drawing a distinction between subjective beliefs and objective behavior in the study of personality and culture. Larger cultural differences can be expected in beliefs and perceptions than in the links between personality and actual behavior. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Cosmic Evolution of Black Holes And Spheroids. 1, the M(BH)-Sigma Relation at Z=0.36

Energy Technology Data Exchange (ETDEWEB)

Woo, Jong-Hak; Treu, Tommaso; /UC, Santa Barbara; Malkan, Matthew A.; /UCLA; Blandford, Roger D.; /KIPAC, Menlo Park

2006-04-17

We test the evolution of the correlation between black hole mass and bulge velocity dispersion (M{sub BH} - {sigma}), using a carefully selected sample of 14 Seyfert 1 galaxies at z = 0.36 {+-} 0.01. We measure velocity dispersion from stellar absorption lines around Mgb (5175 {angstrom}) and Fe (5270 {angstrom}) using high S/N Keck spectra, and estimate black hole mass from the H{beta} line width and the optical luminosity at 5100 {angstrom}, based on the empirically calibrated photo-ionization method. We find a significant offset from the local relation, in the sense that velocity dispersions were smaller for given black hole masses at z = 0.36 than locally. We investigate various sources of systematic uncertainties and find that those cannot account for the observed offset. The measured offset is {Delta} log M{sub BH} = 0.62 {+-} 0.10 {+-} 0.25, i.e. {Delta} log {sigma} = 0.15 {+-} 0.03 {+-} 0.06, where the error bars include a random component and an upper limit to the systematics. At face value, this result implies a substantial growth of bulges in the last 4 Gyr, assuming that the local M{sub BH} - {sigma} relation is the universal evolutionary end-point. Along with two samples of active galaxies with consistently determined black hole mass and stellar velocity dispersion taken from the literature, we quantify the observed evolution with the best fit linear relation, {Delta} log M{sub BH} = (1.66 {+-} 0.43)z + (0.04 {+-} 0.09) with respect to the local relationship of Tremaine et al. (2002), and {Delta} log M{sub BH} = (1.55 {+-} 0.46)z +(0.01 {+-} 0.12) with respect to that of Ferrarese (2002). This result is consistent with the growth of black holes predating the final growth of bulges at these mass scales (<{sigma}> = 170 km s{sup -1}).

How to Write an Article for the

African Journals Online (AJOL)

1974-03-16

Mar 16, 1974 ... line, where the dashes are very much longer than the breaks, may after reduction appear as a solid line. Lettering on illustrations should also be done with this in mind. A map, for instance, drawn on a sheet of paper. 100 x 100 cm can be reduced to Journal size, but if the place-names have been stencilled ...

The Spaces between Us: A Queer?Intersectional Analysis of the Narratives of Black Gay International Students

Science.gov (United States)

Hubain, Bryan S.