Dynamics of Tunneling Centers in Metallic Systems

Dynamics of tunneling centers (TC) in metallic systems is studied, using the technique of bosonization. The interaction of the TC with the conduction electrons of the metal involves two processes, namely, the screening of the TC by electrons, and the so-called electron assisted tunneling. The presence of the latter process leads to a different form of the renormalized tunneling frequency of the TC, and the tunneling motion is damped with a temperature dependent relaxation rate. As the temperature is lowered, the relaxation rate per temperature shows a steep rise as opposed to that in the absence of electron assisted process. It is expected that this behavior should be observed at very low temperatures in a careful experiment. The present work thus tries to go beyond the existing work on the {\it dynamics} of a two-level system in metals, by treating the electron assisted process.Comment: REVTeX twocolumn format, 5 pages, two PostScript figures available on request. Preprint # : imsc 94/3

Entrepreneurial intentions among University’s students in Malaysia

The issue of employability is rising year by year, and Malaysia is also taking it as a serious challenge. The Malaysian government has carried out various initiatives to address the issue of employability; conversely, one of them was successfully promoting the development of entrepreneurship by increasing entrepreneurial courses for instance. The intention was to increase the entrepreneurial intentions amongst university's students to create job opportunities for themselves which could lead to a boost for a developing nation's economy as well. However, the government's initiatives did not succeed as they were expected. The main reason for it ending as a flopped plan was due to failing to identify an individual's intentions. Therefore, the primary purpose of this research is to inspect the Malaysian universities student's intention of being an entrepreneur because, without intention, they might not even consider the option of initiating their own business. This research adapted and integrated the two most common models of examining the entrepreneurial intention, i.e, Theory of Planned Behaviour ('TPB') by Ajzen and Shapero and Sokol's model of an Entrepreneurial Event ('SEE'). This is a quantitative study and a total of 160 students from different Malaysian universities were surveyed using non-probability sampling techniques and by a well-established instrument with the standardized questionnaire, to examine hypothesized relationships. SPSS was used for analyzing the demographic profile and SMART-PLS was utilized for testing the developed hypotheses. The results show that attitude, subjective norms, and perceived behavioural control positively affect the perceived desirability as well as perceived feasibility. Moreover, perceived desirability and perceived feasibility are also positively associated with an entrepreneurial intention. Furthermore, perceived desirability is found as a mediator for the relationship among predictors of entrepreneurial intention but perceived feasibility fails to mediate the association of subjective norm and entrepreneurial intention. By understanding the background of university student's intentions towards entrepreneurship, the Malaysian government and organizations can better present themselves in formulating better initiatives to stimulate and encourage youth to have entrepreneurial intentions in order to initiate their own business. This study also offers some useful managerial implications using the advanced technique of IPM to enhance the H1 H2 H3 H6 H5 H4 H7 H8 performance of critical factors that contribute towards entrepreneurial intentions

Composition and structure of plant communities in the Moist Temperate Forest Ecosystem of the Hindukush Mountains, Pakistan

Peer reviewedPublisher PD

Vestibular schwannomas: Clinical presentation, management and outcome

Objective: To review the demographic trends clinical spectrum, diagnosis, management and outcome of patients with vestibular Schwannoma and to identify areas where improvements are needed.Methods: All patients with vestibular schwannoma admitted to the Aga Khan University Hospital over the past 11 years were reviewed retrospectively.Results: The age range of majority of 22 patients analyzed, was 41-50 years (23%). Hearing loss was the most common presenting symptom (96%). Other clinical features included cranial nerve palsies (59%) and headache (55%). Fifty percent had signs of raised intracranial pressure. Neuroimaging revealed Stage IV b (tumor distorting the brainstem and compressing the 4th ventricle) in 50% cases. Neurosurgical intervention was carried out in 86%; mainly using the retrosigmoid approach. Postoperative complications included facial nerve palsy in 13 (65%) and hydrocephalus in 5 (25%) patients. Hearing determined clinically was preserved in three patients (14%). One patient died during the inpatient stay.Conclusion: Presentation of these patients is late and the outcome is poor

In vitro Maturation and Fertilization of Riverine Buffalo Follicular Oocytes in Media Supplemented with Oestrus Buffalo Serum and Hormones

Effects of two maturation media (TCM-199 and Ham's F-12) with and without the addition of oestrus buffalo serum (OBS) and hormones (FSH, LH, E2) on the maturation rate of buffalo follicular oocytes were evaluated. The results revealed a significant (P P 2+ free Tyrode's medium (63.72%) than in TALP (10.9%) and IVF-TL (32.18%). Thus, TCM-199 containing hormones and OBS appeared better for in vitro maturation, whereas modified Ca2+ free tyrode's medium was found to be more suitable for in vitro fertilization of buffalo follicular oocytes

Predictors of mortality in brain abscess

Objective: Brain abscess carries significant morbidity and mortality. Our objective was to elucidate the clinical presentation of brain abscess and to assess predictors of mortality in these patients.Methods: All patients with a brain abscess presenting to the Aga Khan University Hospital, a tertiary care referral center in Karachi, Pakistan, were studied retrospectively. Statistical analysis involved univariate analysis and a logistic regression model.Results: Among the 66 patients analyzed, a distant metastatic focus of infection was the most commonly identified predisposing factor (29%). Otogenic infection was the commonest contiguous source and sinusitis was noticeably absent. Multiple abscesses were frequent (35%). Streptococci were the most common isolates (39%). Lumbar puncture was performed in 44% and steroids administered in 33%. Treatment was surgical in 58%. Most comatose patients were treated conservatively. Overall mortality was 29%. Univariate analysis identified comatose presentation and identification of a distant focus of infection as predictors of mortality. The logistic regression model, however, identified a distant focus of infection as the only independent predictor.Conclusion: Age greater than 30 years, corticosteroid use, multiple abscesses, performance of lumbar puncture and conservative management had no affect on outcome

Large sharing networks and unusual injection practices explain the rapid rise in HIV among IDUs in Sargodha, Pakistan

<p>Abstract</p> <p>Background</p> <p>Of the nearly 100,000 street-based IDUs in Pakistan, 20% have HIV. We investigated the recent rise in HIV prevalence from 12 to 52% among IDUs in Sargodha despite > 70% coverage with syringe exchanges.</p> <p>Methods</p> <p>We interviewed approximately 150 IDUs and 30 outreach workers in focus group discussions.</p> <p>Results</p> <p>We found six rural and 28 urban injecting locations. Urban locations have about 20–30 people at any time and about 100 daily; rural locations have twice as many (national average: 4–15). About half of the IDUs started injecting within the past 2 years and are not proficient at injecting themselves. They use street injectors, who have 15–16 clients daily. Heroin is almost exclusively the drug used. Most inject 5–7 times daily.</p> <p>Nearly all injectors claim to use fresh syringes. However, they load, inject and share using a locally developed method called scale. Most Pakistani IDUs prefer to double pump drug the syringe, which allows mixing of blood with drug in the syringe. The injector injects 3 ml and keeps 2 ml (the scale) as injection fee. The injector usually pools all the leftover scale (now with some blood mixed with drug) either for his own use or to sell it. Most IDUs backload the scale they buy into their own fresh syringes.</p> <p>Discussion</p> <p>Use of an unprecedented method of injecting drugs that largely bypasses fresh syringes, larger size of sharing networks, higher injection frequency and near universal use of street injectors likely explain for the rapid rise in HIV prevalence among IDUs in Sargodha despite high level provision of fresh syringes. This had been missed by us and the national surveillance, which is quantitative. We have addressed this by hiring injectors as peer outreach workers and increasing syringe supply. Our findings highlight both the importance of qualitative research and operations research to enrich the quality of HIV prevention programs.</p

Dephasing of a Qubit due to Quantum and Classical Noise

The qubit (or a system of two quantum dots) has become a standard paradigm for studying quantum information processes. Our focus is Decoherence due to interaction of the qubit with its environment, leading to noise. We consider quantum noise generated by a dissipative quantum bath. A detailed comparative study with the results for a classical noise source such as generated by a telegraph process, enables us to set limits on the applicability of this process vis a vis its quantum counterpart, as well as lend handle on the parameters that can be tuned for analyzing decoherence. Both Ohmic and non-Ohmic dissipations are treated and appropriate limits are analyzed for facilitating comparison with the telegraph process.Comment: 12 pages, 8 figure

Silencing of MBD1 and MeCP2 in prostate-cancer-derived PC3 cells produces differential gene expression profiles and cellular phenotypes

Alterations in genomic CpG methylation patterns have been found to be associated with cell transformation and neoplasia. Although it is recognized that methylation of CpG residues negatively regulates gene expression, how the various MBPs (methyl-binding proteins) contribute to this process remains elusive. To determine whether the two well characterized proteins MeCP2 (methyl-CpG-binding protein 2) and MBD1 (methyl-CpG-binding domain 1) have distinct or redundant functions, we employed RNAi (RNA interference) to silence their expression in the prostate cancer-derived PC3cell line, and subsequently compared cell growth, invasion and migration properties of these cell lines in addition to their respective mRNA-expressionprofiles. Cells devoid of MeCP2 proliferated more poorly compared with MBD1-deficient cells and the parental PC3 cells. Enhanced apoptosis was observed in MeCP2-deficient cells, whereas apoptosis in parental and MBD1-deficient cells appeared to be equivalent. Boyden chamber invasion and wound-healing migration assays showed that MBD1-silenced cells were both more invasive and migratory compared with MeCP2-silenced cells. Finally, gene chip microarray analyses showed striking differences in the mRNA-expression profiles obtained from MeCP2- and MBD1-depleted cellsrelative to each other as well as when compared with control cells. The results of the present study suggest that MeCP2 and MBD1 silencing appear to affect cellular processes independently in vivo and that discrete sets of genes involved in cellular proliferation, apoptosis, invasion and migration are targeted by each protein