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Search Results: 1 - 10 of 223714 matches for " R Coker "
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The Stellar Winds of Galactic Centre and the Low Accretion Rate of Sgr A*
R. F. Coker
Physics , 2001, DOI: 10.1051/0004-6361:20010870
Abstract: An attempt is made to reconcile the large wind-loss rates of stars in the Galactic Centre (GC) with the predicted low accretion rate for Sgr A*, the putative blackhole at the heart of the Milky Way. It is found that, independent of the details of the accretion, the bound but unaccreted gas has been accumulating in the potential well of Sgr A* for <1000 yrs and thus is not in equilibrium. Otherwise, the gas flows of the region would be visible in both the IR and X-ray. It appears that the blackhole was more active in the recent past due to the passing of a supernova blast shock but is presently in a short-lived dormant phase. The extended low frequency radio emission from the central parsec should visibily increase over the next few decades, as the shock passes completely in front of the absorbing gas and dust near Sgr A*. The GC may become more active in < 100,000 yrs due to either another supernova or sufficient accumulation of stellar winds in the central arcsecond.
3D Simulation of the Gas Dynamics in the Central Parsec of the Galaxy
R. Coker,F. Melia
Physics , 1998,
Abstract: It is thought that many characteristics of the gaseous features within the central parsec of our Galaxy, are associated with the accretion of ambient plasma by a central concentration of mass. Using a 3D hydrodynamical code, we have been simulating this process in order to realistically model the gaseous flows in the center of our Galaxy. In the most recent simulation, we have taken into account the multi-point-like distribution of stellar wind sources, as well as the magnetic heating and radiative cooling of these stellar winds. As expected, we find that the structure of the flow is significantly different from that due to a uniform medium. We also investigate the possibility that Sgr A* is due to a distributed mass concentration instead of the canonical point mass of a black hole. We discuss the physical state of the accreting gas and how our results suggest that Sgr A* is unlikely to be associated with a ``dark cluster''.
Galactic Center: Implications of Recent Chandra Observations for Spherical Accretion Models of Sgr A*
R. F. Coker,S. Markoff
Physics , 2001,
Abstract: At the center of the Milky Way lurks a unique compact nonthermal radio source, Sgr A*. It is thought to be powered by a 2.6 million solar mass black hole that is accreting the stellar winds from the numerous early-type stars that exist in the central parsec. However, until recent high resolution Chandra observations, Sgr A* had never been unequivocably detected at wavelengths shorter than the sub-millimeter. We present a spherical accretion model which is consistent with both the flux and steep spectral shape of the X-ray emission from Sgr A*.
An X-ray Binary Model for the Galactic Center Source IRS 13E
R. F. Coker,J. M. Pittard
Physics , 2000,
Abstract: We present several models for IRS 13E, an infrared, mm and X-ray source in the Galactic Center. Our favored interpretation is that of an early-type binary with strong colliding winds emission. This naturally explains the observed X-ray count rate and the strong infrared emission lines, and has a distinct advantage over competing hypotheses based upon a single star or black-hole system.
Sexual Satisfaction Is Reduced in the Female Patient and Sexually Intimate Partners Following Cancer Therapy  [PDF]
Alan M. Martinez, Julie M. Sroga, Ilana B. Ressler, Leslie Ayensu-Coker, Michael A. Thomas, Steven R. Lindheim
Advances in Sexual Medicine (ASM) , 2014, DOI: 10.4236/asm.2014.44010
Abstract: As cancer survival has continued to improve, cancer patients and their sexually intimate partner (SIP) are confronted with a number of issues including sexual function and overall sexual health. Our study objective was to assess changes in sexual function in women undergoing cancer treatment and their SIP, and attempt to identify areas of needed support and improvement. In this questionnaire-based observational study, females (n = 11) completed a Female Sexual Function Index (FSFI) and for SIP’s (n = 11), a Brief Sexual Function Inventory (BSFI). Level of satisfaction prior to and within 3 months following treatment with surgery, chemotherapy and/or radiation was compared. Mean pre-and post-treatment total (30.7 ± 2.7 vs. 23.2 ± 3.7, p < 0.001) and individual FSFI domains were significantly different for desire (4.2 ± 0.6 vs. 2.6 ± 0.6, p < 0.001), arousal (4.9 ± 0.4 vs. 3.5 ± 0.7, p = 0.001), lubrication (5.5 ± 0.4 vs. 4.5 ± 0.8, p = 0.006), orgasm (5.0 ± 0.6 vs. 3.8 ± 0.7, p = 0.001), satisfaction (5.3 ± 0.6 vs. 3.5 ± 0.9, p < 0.001), though no differences were noted with dyspareunia. For SIP’s, BSFI domain scores for level of satisfaction were significantly lower following partner treatment of SIPs (3.5 ± 5.2 vs. 2.5 ± 5.2, p = 0.004). Overall, female sexual dysfunction was identified in 9% of patients prior to cancer treatment and 91% (n = 11, p < 0.001) following treatment. In conclusion, cancer treatment significantly affects sexual function in female cancer patients and their SIPs. While long term effects on sexual dysfunction are still unclear, short-term health care strategies including treatment, counseling, and appropriate referral for cancer patients and their SIPs should not be overlooked.
The Impact of Assisted Reproduction on Socio-Cultural Values and Social Norms  [PDF]
Steven R. Lindheim, Kathryn Coyne, Leslie Ayensu-Coker, Kathleen O’Leary, Stephanie Sinn, Ami S. Jaeger
Advances in Anthropology (AA) , 2014, DOI: 10.4236/aa.2014.44025
Abstract: Since the birth of the first “test tube” baby, the use of in vitro fertilization (IVF) has undergone an enormous metamorphosis. Initially designed for blocked fallopian tubes, IVF has found a number of other clinical applications over the past 40 years. However, as the science has advanced, traditional norms of conception and parenthood have been challenged and reproductive health ethics, guidelines, and law struggle to keep pace. Controversies and debates have arisen within the law, public policy, and the meaning of family across societies and religious sects. This paper will highlight some of the current and complex social, moral, and legal questions surrounding the implementation and advancement of assisted reproduction including Cross Border Reproductive Care, Oocyte Donation and Consents, Oncofertility, Posthumous Reproduction raising fresh discussion and debate.
Who Should Pay for Global Health, and How Much?
Luis R. Carrasco ,Richard Coker,Alex R. Cook
PLOS Medicine , 2013, DOI: 10.1371/journal.pmed.1001392
KEMANUSIAAN : The Asian Journal of Humanities , 2009,
Abstract: This paper interrogates Yoruba verbal arts and situates culture as a catalyst for development. It is suggested that the intricate resources of oral art, exemplified by Yoruba textual references, are viable ingredients for socio-cultural empowerment. To fully comprehend the dynamics of a society in constant change due to external and internal realities, one must reconsider culture in order to reposition the society. The multidimensional and multidisciplinary significance of Yoruba verbal art demonstrate that culture has a vital role to play in any meaningful socio-political advancement in the Nigerian body polity. The ideas conveyed in proverbial expressions, representing key cultural realities of the Yoruba people, offer insights and ideas for development and social good. The paper submits that a deeper exploration of the intricate resources of verbal art is a viable route to development.
Is there a uniform approach to the management of diffuse parenchymal lung disease (DPLD) in the UK? A national benchmarking exercise
Patricia Macedo, Robina K Coker, Martyn R Partridge
BMC Pulmonary Medicine , 2007, DOI: 10.1186/1471-2466-7-3
Abstract: Consultant members of the British Thoracic Society were mailed a questionnaire seeking their views on the management of three common scenarios in DPLD. They were asked to choose from various management options for each case. Information was also obtained from the respondents on time served as a consultant, type of institution in which they worked and the availability of a local radiologist and histopathologist with an interest/expertise in thoracic medicine.370 out of 689 consultants replied (54% response rate). There were many differences in the approach to the management of all three cases. Given a scenario of relapsing pulmonary sarcoidosis in a lady with multiple co-morbidities, half of respondents would institute treatment with a variety of immunosuppressants while a half would simply observe. 42% would refer a 57-year old lady with new onset DPLD for a surgical lung biopsy, while a similar number would not. 80% would have referred her for transplantation, but a fifth would not. 50% of consultants from district general hospitals would have opted for a surgical biopsy compared to 24% from cardiothoracic centres: this may reflect greater availability of a radiologist with special interest in thoracic imaging in cardiothoracic centres, obviating the need for tissue diagnosis. Faced with an elderly male with high resolution CT thorax (HRCT) evidence of usual interstitial pneumonia (UIP), three quarters would observe, while a quarter would start immunosuppressants. 11% would refer for a surgical biopsy. 14% of UK pulmonologists responding to the survey revealed they had no access to a radiologist with an interest in thoracic radiology.From our survey, it appears there is a lack of consensus in the management of DPLD. This may reflect lack of evidence, lack of resources or a failure to implement current guidelines.Benchmarking is the comparison of a performance or process to the work or results of others. It involves learning, sharing information and adopting best pr
Models of Wave Supported Clumps in Giant Molecular Clouds
R. F. Coker,J. G. L. Rae,T. W. Hartquist
Physics , 2000,
Abstract: We present plane-parallel equilibrium models of molecular clumps that are supported by Alfven waves damped by the linear process of ion-neutral friction. We used a WKB approximation to treat the inward propagation of waves and adopted a realistic ionization structure influenced by dissociation and ionization due to photons of external origin. The model clumps are larger and less centrally condensed than those obtained for an assumed ionization structure, used in some previous studies, that is more appropriate for dark regions.
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