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Search Results: 1 - 10 of 189747 matches for " Cecil G. Helman "
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Doen a versus Enfermidade na Clínica Geral
Cecil G. Helman
Campos - Revista de Antropologia Social , 2009,
Division by four
Peter G. Doyle,Cecil Qiu
Mathematics , 2015,
Abstract: Write A<=B if there is an injection from A to B, and A==B if there is a bijection. We give a simple proof that for finite n, nA<=nB implies A<=B. From the Cantor-Bernstein theorem it then follows that nA==nB implies A==B. These results have a long and tangled history, of which this paper is meant to be the culmination.
Bubbles, bow-shocks, and bullets over broad-lines: three ionized outflows resolved with hst
G. Cecil,P. Ferruit,S. Veilleux
Revista mexicana de astronomía y astrofísica , 2002,
Abstract: Las im agenes y espectros de ujos de alta velocidad de AGNs (n ucleos activos de galaxias) obtenidos con el HST logran: (1) Mostrar sistemas de choque a proa/disco de Mach de tama~nos de 500 en las puntas del radio jet de NGC 4258. Argumentamos que el jet ha precesado a su orientaci on corriente observada a escalas de VLBI. (2) Resolver los per les de las l neas de [O III] 5007 A y H en la NLR de NGC 1068, y mostrar nudos compactos corridos al azul a velocidades >3100 km s...
Chandra Observations and the Nature of the Anomalous Arms of NGC 4258 (M 106)
A. S. Wilson,Y. Yang,G. Cecil
Physics , 2001, DOI: 10.1086/322766
Abstract: This paper presents high resolution X-ray observations with Chandra of NGC 4258 and infers the nature of the so called ``anomalous arms'' in this galaxy. The anomalous arms dominate the X-ray image; diffuse X-ray emission from the ``plateaux'' regions, seen in radio and H$\alpha$ imaging, is also found. X-ray spectra have been obtained at various locations along the anomalous arms and are well described by thermal (mekal) models with kT in the range 0.37 - 0.6 keV. The previously known kpc-scale radio jets are surrounded by cocoons of hot X-ray emitting gas for the first 350 pc of their length. The radio jets, seen in previous VLBA and VLA observations, propagate perpendicular to the compact nuclear gas disk (imaged in water vapor maser emission). The angle between the jets and the rotation axis of the galactic disk is 60$^{\circ}$. The jets shock the normal interstellar gas along the first 350 pc of their length, causing the hot, X-ray emitting cocoons noted above. At a height of z = 175 pc from the disk plane, the jets exit the normal gas disk and then propagate though the low density halo until they reach ``hot spots'' (at 870 pc and 1.7 kpc from the nucleus), which are seen in radio, optical line and X-ray emission. These jets must drive mass motions into the low density halo gas. This high velocity halo gas impacts on the dense galactic gas disk and shock heats it along and around a ``line of damage'', which is the projection of the jets onto the galactic gas disk as viewed down the galaxy disk rotation axis. However, because NGC 4258 is highly inclined ($i$ = 64$^{\circ}$), the ``line of damage'' projects on the sky in a different direction to the jets themselves. We calculate the expected p.a. of the ``line of damage'' on the sky and find that it coincides with the anomalous arms to within 2$^{\circ}$. (Abstract truncated).
Classical Spectroscopy
J. Bland-Hawthorn,G. N. Cecil
Physics , 1997,
Abstract: Tunable filters are set to revolutionize many aspects of experimental astrophysics, particularly for applications in observational cosmology. After a summary of the fundamentals of classical spectroscopy, we present a review of the current technologies on offer. For extragalactic studies, small-gap etalons are the preferred option in terms of cost, photometric performance and throughput (e.g. the TAURUS Tunable Filter; http://www.aao.gov.au/).
Antibiotics Prophylaxis in Patients with CAKUT, Does It Actually Prevent UTI? A Single Center Experience at South Africa  [PDF]
Nneka Chioma Okoronkwo, Abdullahi Mudi, Cecil Levy, Thuli Khumalo, G. Moonsamy
Open Journal of Nephrology (OJNeph) , 2018, DOI: 10.4236/ojneph.2018.84011
Abstract: Background: Congenital anomalies of the kidney and urinary tract (CAKUT) are a well-documented risk factor for the development of urinary tract infection (UTI) in children. Prevention of UTI in this group of patients is advocated due to their increased risk of renal scarring, hypertension and end stage kidney failure. Methods: A 10-year retrospective review of CAKUT patients at the Johannesburg Academic Hospital, who were placed on prophylactic antibiotics over a certain period was done. The rate of UTI, the types of causative organisms isolated and the efficacy of prophylactic antibiotics in preventing UTI were documented. Results: Thirty-six (36) out of 134 patients had been started on prophylactic antibiotics after the diagnosis of CAKUT was made. There was a statistically significant association between the use of prophylactic antibiotics and the rate of UTI (p < 0.001). Patients who were not on a prophylactic antibiotic were five times more likely to have a UTI than those who were on a prophylactic antibiotic (OR = 5.21, P = 0.001, 95% CI: 1.9906 - 13.6277). There was a statistically significant association between the type of bacteria isolated and the use of antibiotic prophylaxis (p = 0.031). Conclusion: Antibiotic prophylaxis was very effective in decreasing the rate of UTI in our cohort of patients with CAKUT.
A model-based predictive control scheme for steal rolling mills using neural networks
Gálvez, J. M.;Zárate, Luis E.;Helman, H.;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2003, DOI: 10.1590/S1678-58782003000100012
Abstract: a capital issue in roll-gap control for rolling mill plants is the difficulty to measure the output thickness without including time delays in the control loop. time delays are a consequence of the possible locations for the output thickness sensor, which usually is located some distance away from the roll gap. in this work, a new model-based predictive control law is proposed. the new scheme is a neural network based predictive control structure which is applied to roll-gap control with outstanding results. it is shown that the neural network based predictive control permits to overcome the existing time delays in the system dynamics. the proposed scheme implements a virtual thickness sensor, which releases an accurate estimate of the actual output thickness. it is shown that the dynamic response of the rolling mill system can be substantially improved by using the proposed controller. simulation results are presented to illustrate the controller performance.
Representa??o e controle de laminadores tandem baseado em fun??es de sensibilidade obtidos através de redes neurais
Zárate, Luis E.;Helman, Horacio;Gálvez, José M.;
Sba: Controle & Automa??o Sociedade Brasileira de Automatica , 2003, DOI: 10.1590/S0103-17592003000200002
Abstract: the mathematical modeling of the tandem mills involves non lineal expressions of difficult analytic and numeric solutions. if the model proposed by alexander (1972), considered the most complete (with larger effort computational) it be considered to describe the process in each stand, this hinders the application of that model in control and supervision systems "on-line". for resolve such difficulty, in this work a representation of the sensibility of the process by means of neural networks is presented. the new representation allows to obtain the value of the output thickness, for each stand, in the form predictive, eliminating the need of the sensor of thickness, usually ray-x, that introduce delays in the loops control. other aspect of this work is the application of predictive control for tandem mills, based in neural networks. simulation results are presented.
Disruption of the MyoD/p21 Pathway in Rhabdomyosarcoma
Michael Weintraub,Thea Kalebic,Lee J. Helman,Kishor G. Bhatia
Sarcoma , 1997, DOI: 10.1080/13577149778218
Representa o e controle de laminadores tandem baseado em fun es de sensibilidade obtidos através de redes neurais
Zárate Luis E.,Helman Horacio,Gálvez José M.
Sba: Controle & Automa??o Sociedade Brasileira de Automatica , 2003,
Abstract: A modelagem matemática do processo de lamina o em tandem envolve express es n o lineares de difíceis solu es analíticas e/ou numéricas. Se o modelo proposto por Alexander (1972), considerado um dos mais completos e o de maior esfor o computacional, for considerado para descrever o processo de deforma o da tira em cada cadeira, isto dificultaria a aplica o deste modelo em sistemas de controle e supervis o "on-line". Para sobrelevar tal dificuldade, um dos propósitos deste trabalho é a representa o da sensibilidade do processo por meio de Redes Neurais Artificiais. A nova representa o permite obter o valor da espessura final, de cada cadeira, na forma preditiva eliminando a necessidade de sensores de espessura, normalmente raio-X, que introduzem atrasos de tempos nas malhas de controle. O segundo aspecto deste trabalho é a aplica o de controle preditivo para laminadores tandem com estruturas baseadas em redes neurais artificiais que permitam sobrelevar o retardo de tempo existente nestes processos. Resultados da representatividade do laminador tandem por meio de redes neurais e simula o do controlador proposto s o apresentados.
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