2,711 research outputs found
The thermodynamic structure of Einstein tensor
We analyze the generic structure of Einstein tensor projected onto a 2-D
spacelike surface S defined by unit timelike and spacelike vectors u_i and n_i
respectively, which describe an accelerated observer (see text). Assuming that
flow along u_i defines an approximate Killing vector X_i, we then show that
near the corresponding Rindler horizon, the flux j_a=G_ab X^b along the ingoing
null geodesics k_i normalised to have unit Killing energy, given by j . k, has
a natural thermodynamic interpretation. Moreover, change in cross-sectional
area of the k_i congruence yields the required change in area of S under
virtual displacements \emph{normal} to it. The main aim of this note is to
clearly demonstrate how, and why, the content of Einstein equations under such
horizon deformations, originally pointed out by Padmanabhan, is essentially
different from the result of Jacobson, who employed the so called Clausius
relation in an attempt to derive Einstein equations from such a Clausius
relation. More specifically, we show how a \emph{very specific geometric term}
[reminiscent of Hawking's quasi-local expression for energy of spheres]
corresponding to change in \emph{gravitational energy} arises inevitably in the
first law: dE_G/d{\lambda} \alpha \int_{H} dA R_(2) (see text) -- the
contribution of this purely geometric term would be missed in attempts to
obtain area (and hence entropy) change by integrating the Raychaudhuri
equation.Comment: added comments and references; matches final version accepted in
Phys. Rev.
Foreign direct investment in Malaysia: Trends and prospects
This paper reports on a study analyzing recent trends, pattern and prospects of the foreign direct investment (FDI) in Malaysia in the post-1997 financial crisis period. Among the ASEAN-4 countries, Malaysia continues to remain as the main centre for attracting FDI.The macroeconomic variables such as GDP, exports and employment are found to be positively influenced by the growth of FDI in Malaysia. To enhance the positive effect of FDI on the growth process of the Malaysian economy the flow of FDI into export-oriented sector and use of domestic inputs by the foreign oriented firms need to be encouraged.It is suggested that for sustained flow of FDI, continual price stability, macroeconomic balances, good governance and economic liberalization reforms are crucially important in the country.In the event of declining inflows of FDI, Malaysia has to shiR towards inward looking policies and search other alternatives to sustain its growth and economic prosperity by seeking more investment oufflows as a global player
New technology in radiological diagnosis: An investigation of diagnostic image quality in digital displays of radiographs
Digital radiology is undergoing rapid evolution. Its objectives can be summarized as the creation within the modern radiology department - and indeed within the entire hospital - of a harmonious, integrated, electronic network capable of handling all diagnostic radiological images, obviating the need for conventional film-based radiology. One of the limiting factors in the introduction and exploitation of digital technology is the issue of image display quality: if electronic display systems are to be widely used for primary radiological diagnosis, it is essential that the diagnostic quality of the displayed images should not be compromised. From the perspective of the practising radiologist, this study examines the performance of the first two commercially available digital radiological display systems to be purchased and installed in a British hospital. This work incorporates an extensive observer performance investigation of image quality from existing 1024- and 1280-line display systems, and suggests that displayed images digitized at a pixel size of 210?m show a significant reduction in diagnostic performance when compared with original film. Such systems appear to be unsuitable for primary radiological diagnosis of subtle lesions. Some of the physical properties of such systems, some relevant methodological issues, and the relationship between image quality and other factors influencing the development acceptance and implementation of digital technology, have also been investigated; the results are presented. This is a controversial subject, and conflicting views have been expressed in the British literature concerning the issue of whether or not the technology is now ready for total system implementation; the view of this author is that careful testing of display systems, and of every other component of digital networks, should precede their entry into clinical use
Infective endocarditis secondary to mycoplasma pneumoniae
Mycoplasma pneumoniae (MP) is a gram-positive bacterium most commonly associated with community-acquired pneumonia in adults. It can also involve other systems of the body. Cardiovascular complications include pericarditis, myocarditis, congestive cardiac failure, and, rarely, infective endocarditis. We report a case of infective endocarditis secondary to MP infection in an adult. We treated our patient with doxycycline, which showed significant improvement
Rainfall but not selective logging affect changes in abundance of tropical forest butterfly in Sabah, Borneo
We investigated the effects of rainfall on the distribution and abundance of the satyrine butterfly Ragadia makuta in selectively logged and unlogged forest on Borneo. In 1997-98, there was a severe El Nino-Southern Oscillation (ENSO) drought, and annual surveys over a 4-y period showed that abundance of R. makuta was greatly reduced during the drought, but that populations quickly recovered after it. Monthly surveys over a 12-mo period of typical rainfall showed that high rainfall in the month preceding surveys significantly reduced butterfly abundance. Butterfly abundance and distribution did not differ between selectively logged and unlogged areas in either monthly or annual surveys and there was no difference between selectively logged and unlogged areas in the pattern of post-drought recovery. These results indicate that the abundance of R. makuta was significantly reduced both after high rainfall and during severe drought, but that these impacts were short-lived and were not affected by habitat disturbance. ENSO droughts on Borneo naturally often lead to widespread forest fires and thus impacts of ENSO events for butterflies are more likely to be due to indirect effects of habitat loss, rather than direct effects of drought on butterfly population dynamics
Doppler Measurements Using a Coherent Ultrawideband Random Noise Radar
The University of Nebraska has developed a random noise radar system which transmits an ultrawideband random noise waveform with a uniform power spectral density (PSD) in the 1-2 GHz frequency range. Simulation studies and controlled laboratory tests confirm the system\u27s ability to preserve the instantaneous phase of the received signal [l, 2]. The potential of the system to characterize the Doppler shift of moving targets exhibiting varying linear and rotational velocities was clearly demonstrated [2]. This paper provides with the results of recent field experiments at a range of about 200 m which confirm the ability of the system to be used as a Doppler radar in operational scenarios
The Relationship between Ethical Leadership and Teachers Continuance Organizational Commitment
The current study aims to investigate the relationship between the behavior of ethical leaders and their continuance organizational commitment, and also to discover the mediational impact of teachers' loyalty on their relationships at the international schools in Jeddah, Kingdom of Saudi Arabia (KSA).
The study employed a quantitative approach as follows: a formatted questionnaire was distributed to a random sample, of which 372 valid questionnaires were returned to the researchers. In addition to examining the research hypotheses, several statistical methods were used to analyse the compiled data. The study showed that when the supervisor displays positive behaviors and a moral leadership style, this has leverage on the employees’ performance. The study found that there is a statistically important engagement relevance between moral leadership and teachers’ loyalty. Moreover, the study showed that teachers' loyalty facilitated the association between ethical leadership and teachers' continuance commitment toward organization. The current research recommended that it was essential to increase the standard of moral leadership for managers, to positively influence continuance commitment to the organisation, and to enhance teachers' loyalty
Synthesis of some Schiff's bases derivatives from aminoazo compounds
Reaction of,2- [( 4- amio phenyl ) diazenyl] 1,3,4- thiadiazole -5- thiol (S1) with
p- chlorobenzeldehyde,3,4 – dimethoxy benzaldehyde and pyrrol-2- carbonxaldehyde gave -5- [{4-(4-chlorobenzylidene amino) phenyl} diezenyl]-1,3,4- thiadiazole-2- thiol (S2),5-[{ 4-[(3,4- dimethoxybenzyldene )amino phenyl ] diazenyl)-1,3,4- thiadiazole-2-thiol,(S3) and -5- [4-(1,H – pyrrol -2- yl- methylene)amino phenyl] diazenyl)-1,3,4- thiadiazole-2- thiol (S4) respectively as schiff's bases compounds. On the same route-2-[(4-amino-1- naphthyl ) diazenyl] -1,3,4- thiadiazole -5- thiol (S5) reacts with –p- chloro benzaldehyde and –m- nitrobenzaldehyde to give the follwing schiff's bases -5-[{ 4-(4- chloro benzylidene ) amino -1- naphthyl} diazenyl] -1,3,4- thiadiazole -2- thiol (S6) and -5- ({ 4- [3- nitrobenzylidene) amino] -1- naphthyl({ diazenyl) -1,3,4 – thiadiazole-2- thiol (S7). Sn2 reaction was carried out by the reaction of compound (S6,S7) with bromo ethyl acetate to get ethyl[5{4-(4- chlorobenzylidene amino)-1- naphthyl} diazenyl] -1- 1,3,4- thiadiazole-2- yl- thio] acetate (S8) and ethyl [5-{4- (2- nitrobenzylidene amino)-1- naphthyl diazenyl] -1,3,4- thiadiazole -2-yl-acetate (S9).(Fig.1)
Assessment of Salivary and Serum Proteins in Patients with Oral Tumors
The qualified subjects for this study included 33 patients with benign and malignant oral tumors aged 15-75 years and 31 matched age and gender healthy subjects used as control. Proteins measurements included total protein, albumin, globulines in sera and saliva samples, and immunoglobulins (IgG, IgM, IgA) in sera samples of control and patients. Meanwhile, polyacrylamide gel electrophoresis (PAGE) was used to differentiate between protein patterns in both serum and saliva samples among the studied groups. The gel was also stained for glycoprotein to evaluate as well the changes in glycoprotein contents. For total protein, the results revealed a signifigant increase (P?0.01) in both samples (serum and saliva) of patient group. Albumin concentration shows presence of a high significant decrease (P=0.001) in sera samples but a significant increase (
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