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Search Results: 1 - 10 of 1698 matches for " Harun-Or Rashid "
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Cosmological Parameters and Black Holes
S. M. Harun-or-Rashid
Physics , 2002,
Abstract: This work is related to different questions within cosmology. The principal idea herein is to develop cosmological knowledge making use of the analyses of observational data in order to find the values of the matter density Omega_m and vacuum energy density Omega_Lambda. Data fitting is carried out using two statistical methods, chi^2 and maximum likelihood. The data analysis exhibits that a low density and flat Universe is strongly favoured. Applying the Omega_m value found for clusters of galaxies, we demonstrate that clusters have very little room for baryonic dark matter. An upper limit to the small but non-negligible sum of baryonic dark matter and galaxy mass can be estimated, requiring the use of special statistics. A Toroidal Black Hole (TBH) study, in contrast to the Spherical Black Hole (SBH), shows that the TBH can be used as an important tool in explaining AGN phenomena.
Nurse managers' experience with ethical issues in six government hospitals in Malaysia: A cross-sectional study
Maizura Musa, Md Harun-Or-Rashid, Junichi Sakamoto
BMC Medical Ethics , 2011, DOI: 10.1186/1472-6939-12-23
Abstract: A cross-sectional study was conducted in August-September, 2010 involving 417 (69.2%) of total 603 nurse managers in the six Malaysian government hospitals. Data were collected using three-part self-administered questionnaire. Part I was regarding participants' demographics. Part II was about the frequency and areas of management where ethical issues were experienced, and scoring of the importance of 11 pre-identified ethical issues. Part III asked how they dealt with ethical issues in general; ways to deal with the 11 pre-identified ethical issues, and perceived stress level. Data were analyzed using descriptive statistics, cross-tabulations and Pearson's Chi-square.A total of 397 (95.2%) participants experienced ethical issues and 47.2% experienced them on weekly to daily basis. Experiencing ethical issues were not associated with areas of practice. Top area of management where ethical issues were encountered was "staff management", but "patient care" related ethical issues were rated as most important. Majority would "discuss with other nurses" in dealing generally with the issues. For pre-identified ethical issues regarding "patient care", "discuss with doctors" was preferred. Only 18.1% referred issues to "ethics committees" and 53.0% to the code of ethics.Nurse managers, regardless of their areas of practice, frequently experienced ethical issues. For dealing with these, team-approach needs to be emphasized. Proper understanding of the code of ethics is needed to provide basis for reasoning.The advances in medicine and a more demanding healthcare environment have given rise to various complex ethical issues. Together, they have caused increasing pressure to healthcare professionals, of which nurses are of no exception. A survey by the American Nurses Association (ANA) Center for Ethics and Human Rights at the ANA Convention in 1994 reported that as high as 79% of their members were confronted with ethical issues on daily to weekly basis [1]. What is meant by "
Selective Extraction of Co(II) in the Presence of Mn(II), Ni(II) and Cu(II) Using Salting-out Phase Separation Method
Ahsan Habib,Md. Wahiduzzaman,Harun-Or Rashid,Anarul Islam
Pakistan Journal of Analytical and Environmental Chemistry , 2008,
Abstract: Extraction of Co(II) in the presence of Mn(II), Ni(II) and Cu(II) has been studied using the mixture of 2-propanol with water upon the addition of CaCl2 in the concentration range of 3.0 – 5.0 mol dm-3 (M). Co(II) was extracted selectively to the extent of 80% into the 2-propanol phase at 5.0 M CaCl2. The percent of extraction of other transition metal ions, for example Mn(II), Ni(II) and Cu(II) was much lower than that of Co(II), but they were stripped in the aqueous phase upon addition of CaCl2. Therefore, selective extraction of Co(II) from these metal ions was attained by using the mixture of water and 2-propanol. Co(II) was extracted as CoCl42- from the aqueous phase into the 2-propanol phase through the formation of ion pair, Ca2+ - CoCl42-. A mechanism is proposed to explain the extraction.
Determination of the dynamical parameters of the Universe and its age
Matts Roos,S. M. Harun-or-Rashid
Physics , 1999,
Abstract: We determine the density parameters $\Omega_m$ of gravitating matter and $\Omega_{\Lambda}$ of vacuum energy, by making a $\chi^2$ fit to nine independent astrophysical constraints. Paying rigorous attention to statistical detail, we find that the present best values are $\Omega_m=0.31\pm 0.07, \Omega_{\Lambda}=0.70\pm 0.13$, where these $1\sigma$ errors are approximately Gaussian (thus trivially convertible to whatever percentage confidence range desired). The total $\chi^2$ is 2.5 for 7 degrees of freedom, testifying that the various systematic errors included are generous. Since $\Omega_m + \Omega_{\Lambda}= 1.01\pm 0.15$, it follows that the Einstein-de Sitter model is very strongly ruled out, that also any low-density model with $\Omega_{\Lambda}=0$ is ruled out, and that a flat cosmology is not only possible, but clearly preferred. In the flat case we find $\Omega_m=0.31\pm 0.04$, from which it follows that the age of the Universe is $t_0 = 13.7^{+1.2}_{-1.1}(0.68/h)$ Gyr.
How flat is the Universe?
Matts Roos,S. M. Harun-or-Rashid
Physics , 2000,
Abstract: In order to answer this question, we combine ten independent astrophysical constraints in the space of the density parameters $\Omega_m$ of gravitating matter and $\Omega_{\Lambda}$ of vacuum energy. We find that $\Omega_m=0.31\pm 0.07$, $\Omega_{\Lambda}=0.63\pm 0.21$, and thus $\Omega_m + \Omega_{\Lambda}=0.94\pm 0.22$. The total $\chi^2$ is 4.1 for 8 degrees of freedom, testifying that the various systematic errors included are generous. We also determine $\Omega_m$ in the exactly flat case. Five supplementary flat-case constraints can then be included in our fit, with the result $\Omega_m=1-\Omega_{\Lambda}= 0.337\pm0.031$. It follows that the age of the Universe is $t_0 = 13.5\pm 1.3$ (0.68/h) Gyr.
The case for a cosmological constant
Matts Roos,S. M. Harun-or-Rashid
Physics , 1997,
Abstract: Taking the Hubble constant to be in the range 60 - 75 km/s Mpc we show that three independent conditions strongly rule out the standard model of flat space with vanishing cosmological constant.
The Dynamical Parameters of the Universe
Matts Roos,S. M. Harun-or-Rashid
Physics , 2002,
Abstract: The results of different analyses of the dynamical parameters of the Universe are converging towards agreement. Remaining disagreements reflect systematic errors coming either from the observations or from differences in the methods of analysis. Compiling the most precise parameter values with our estimates of such systematic errors added, we find the following best values: the baryonic density parameter Omega_bh^2 = 0.019 +/- 0.02, the density parameter of the matter component Omega_m = 0.29 +/- 0.06, the density parameter of the cosmological constant Omega_lambda = 0.71 +/- 0.07, the spectral index of scalar fluctuations n_s = 1.02 +/- 0.08, the equation of state of the cosmological constant w_lambda < -0.86, and the deceleration parameter q_0 = -0.56 +/- 0.04. We do not modify the published best values of the Hubble parameter H_0 = 0.73 +/- 0.07 and the total density parameter Omega_0 ^{+0.03}_{-0.02}.
The flatness of the Universe is robust
Matts Roos,S. M. Harun-or-Rashid
Physics , 2000,
Abstract: We combine the two balloon experiments BOOMERANG and MAXIMA-1 with our previous fit which used 9 constraints and concluded that the Universe is flat. The result is that the flatness is robust, $\Omega_0 = 0.97 \pm 0.05$.
A toroidal black hole for the AGN phenomenon
Fulvio Pompilio,S. M. Harun-or-Rashid,Matts Roos
Physics , 2000,
Abstract: A new approach to the study of the AGN phenomenon is proposed, in which the nucleus activity is related to the metric of the inner massive black hole. The possibility of a Toroidal Black Hole (TBH), in contrast to the usual Spherical Black Hole (SBH), is discussed as a powerful tool in understanding AGN related phenomena, such as the energetics, the production of jets and the acceleration of particles, the shape of the magnetic field and the lifetime of nucleus activity.
Statistical evaluation of the observational information on $Ω_m$ and $Ω_Λ$
S. M. Harun-or-Rashid,M. Roos
Physics , 2001, DOI: 10.1051/0004-6361:20010627
Abstract: We undertake a critical evaluation of recent observational information on $\Omega_m$ and $\Omega_\Lambda$ in order to identify possible sources of systematic errors and effects of simplified statistical analyses. We combine observations for which the results have been published in the form of likelihood contours in the $\Omega_m ,\Omega_\Lambda$ plane. We approximate the contours by fifth order polynomials, and we then use the maximum likelihood method to obtain joint likelihood contours for the combined data. In the choice of statistical merits we aim at minimum loss of information rather than at minimum variance. We find that $\Omega_0 = \Omega_m + \Omega_\Lambda = 0.99\pm 0.04 \pm 0.03$, where the first error is mainly statistical and the second error is systematical. In a flat Universe we find $\Omega_m^{flat} = 0.31 \pm 0.04 \pm 0.04$.
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