The Influence of Non-Equilibrium Pressure on Rotating Flows

This study was undertaken to investigate the influence of pressure relaxation on steady, incompressible flows with strong streamline curvature. In the early part of this dissertation research, the significance of non-equilibrium pressure forces in controlling the structure of a steady, two dimensional axial vortex was demonstrated. In order to extend the study of pressure relaxation influences on more complex rotating flows, this dissertation has examined other rotating flow features that can be associated with hurricanes, tornadoes and dust devils. To model these flows, modified boundary layer equations were developed for a fluid column rotating near a solid plane including the influence of non-equilibrium pressure forces. The far-field boundary conditions were inferred using the asymptotic behavior of the governing equations, and the boundary conditions for the axial and radial components of velocity were shown to be dependent on the pressure relaxation coefficient, η p, and the characteristic angular velocity of the rotating fluid column, ω. This research has shown for the first time that the inclusion of non-equilibrium pressure results in a free-standing stagnation plane at the top of a funnel shaped rotating fluid column, which is consistent with observational data for hurricanes, tornadoes and dust devils. It has also been shown that in the absence of non-equilibrium pressure, the stagnation plane for rotating flows cannot be observed. The velocity and pressure distributions resulting from incorporating non-equilibrium pressure effects were then compared with available observational data for tornadoes and dust devils. The general profiles of the velocity and pressure distributions were found to be in good agreement with physical measurements, which was not possible without introducing empirical turbulence effects, in the absence of non-equilibrium pressure effects

Do Outliers Matter in Return and Volatility Linkages? A Case of Sectoral Stock of PSX and Brent Oil

This paper focuses at the return and volatility link between Brent Oil and stock sectors of Pakistan Stock Exchange by taking into account the outliers. The newly proposed Laurent et al. (2016) methodology has been applied for the detection and correction of outliers. Bivariate VAR(1)-AGARCH(1,1) model has been estimated using data sampled from 01-01-2001 till 31-12-2015. Optimal weights and hedge ratios for oil-stock portfolio holdings have also been analyzed. It has been observed that the model estimates are alive to the presence of outliers. Unidirectional short-run price spillovers are found significant from oil market to the stock sectors. Whereas, no volatility spillover between Brent oil and sectors of Pakistan Stock Exchange have been found neither in the short-run and nor in the long-run. The outcomes of this study will help investors, portfolio and hedge fund managers in making sane decisions about portfolio diversification, risk management, and international assets allocation

Infodemics and its Effect on Mental Health of Medical Students of IMDC during COVID-19 Pandemic

IntroductionGlobally rising the number of daily COVID-19 cases has triggered the incredible surge in the information (and misinformation) regarding COVID-19. This misinformation was about numbers of cases, inaccurate guidelines, advertisement of unapproved treatments, and remedies as cures. The increasing prevalence of depression and anxiety was found to be linked directly to the misinformation catered from social media. The study aims to explore the mental health of medical students due to a surge in information and misinformation regarding Covid-19.Materials and MethodsThis cross-sectional study was conducted online from August 2020 to January, 2021. 227 MBBS students of IMDC (1st year to final year with age range 19-25 years) were invited to participate in an online survey through Google docs. Those who were on medication for anxiety and depression were excluded from the study. The use of the data for research purposes was explained and written consent in the first section of the online survey was given to all participants before filling the questionnaire which was divided into 3 sections. The first part was about Demographic information. The second part consisted of 5 questions about info-media use and the third part consisting of 12 questions about mental health including stress-related and behavioral changes, somatic symptoms, emotional disturbance, and cognitive functioning during the covid-19 pandemic. Ethical Approval was taken from the ethical committee of IMDC. A Chi-square test was applied to calculate the significance of qualitative variables and determine the prevalence of mental health.ResultsThe total number of students who participated in this survey were 227 (28.2% males and 71.8% females). Among types of info-media, Whats-app was used most frequently by MBBS students. Different questions were asked regarding Info-media usage and mental health. A significant association was found between gender (Both males and females) and feelings of fear and worry (p-value 0.004**), feeling socially isolated(p= 0.005**), difficulty in communicating with people (p = 0.021*), feeling confused in decision making as time progressed( 0.008**), lack of interest in studying or difficulty in concentration during this time (p 0.037*) and effect on memorizing ability (0.000)**.MBBS students who were regularly using Info-media showed a significant disturbance in mental health problems including stress-related and behavioral changes and somatic symptoms. They were found to be significantly fearful and worried (p-value 0.010*), had difficulty in communicating with people regarding covid-19(p-value 0.021*), and also felt a change in appetite-valuable 0.030*). No serious mental health problem was found related to cognitive functioning. ConclusionIn conclusion, our findings show that there is a high prevalence of mental health problems, which were positively associated with frequent use of info-media during the COVID-19 outbreak

Use of femoral nail with spiral blade in subtrochanteric fractures

Objective: The aim of this study was to evaluate the outcome of acute subtrochanteric fractures managed with intramedullary nail and spiral blade fixation of the proximal fragment.Methods: Charts of 33 patients (17 males and 16 females) with acute subtrochanteric fractures operated with intramedullary nail and spiral blade at our institution between March 2006 and February 2011 were retrospectively reviewed. The most common (67%) mechanism of injury was ground-level fall, predominantly involving elderly patients. Results were evaluated in terms of union time, implant failure rate, infection rate and functional outcome.Results: Mean duration of surgery was 2.4 hours and average length of hospital stay was 7 days. Mean radiological healing time was 16 weeks. Good healing occurred in 31 (94%) patients within 6 months of surgery. Uneventful healing occurred in 28 (85%) patients and 3 (9%) had delayed healing requiring dynamization in two patients and bone grafting in one. Implant failure occurred in 2 (6%) patients within 2 months of index surgery requiring repeat surgery. One (3%) patient had varus malunion.Conclusion: Intramedullary nailing with spiral blade is a good option for acute subtrochanteric fractures with promising results. We think that this is a superior device compared to conventional methods of fixation for subtrochanteric fractures

Prophylaxis against heterotopic ossification after elbow and acetabular fractures — do we really need it

Abstract OBJECTIVE: To compare the efficacy and safety of prophylactic modalities for heterotopic ossification prevention after elbow and acetabular surgeries. METHODS: The retrospective chart review was conducted at the Aga Khan University Hospital and comprised record of patients who underwent open reduction and internal fixation for elbow and acetabular fractures between 2010 and 2013. Data was classified into three groups: Group A patients had received single dose of radiotherapy; Group B patients had received indomethacin, and Group C patients had not received any prophylaxis. Outcome variables included time-to-fracture healing, heterotopic ossification, non-union and wound infection. RESULTS: Of the 104patients 70(67.3%) had elbow fractures and 34(32.7%) had acetabular fractures. Out of the 70patients with elbow fractures, 28(27%) were in Group A, 24(23%) in Group B, and 18(17%) in Group C. In Group A, 4(22%) patients had wound infection compared to 1(5.5%) patient in Group C (p=0.131). One (4%) patient in Group B and 1(5.5%) in Group C developed heterotopic ossification (p=0.486). Non-union occurred in 1(4%) patient in Group B and 1(5.5%) in Group C. Out of the 34 patients with acetabular fractures, 11(32.3%) were in Group A, 10(29.4%) in Group B, and 13(38.2%) in Group C. In Group A, 2(18.2%) patients developed wound infection. Only 1(7.6%) patient in Group C developed heterotopic ossification. CONCLUSIONS: No role of radiotherapy or indomethacin was detected in the prevention of heterotopic ossification

Poverty in rural Pakistan

The major aim of this chapter is to extend the poverty studies of the sixties into the seventies, it also re-examines the evidence on rural poverty for the sixties, supplementing the results with new evidence where available, mainly to see whether the conclusions reached by earlier authors were in fact justified. An examination of the trends in rural poverty into the seventies has gained additional importance for a number of reasons. It could be argued, with some merit, that since the major increases in agricultural production took place in the latter half of the sixties (mainly after 1966) the time period covered by the earlier studies, i.e. till 1971/72 was not long enough to evaluate its "spill over" effect on rural poverty. The early seventies also saw the introduction of structural changes mainly in the form of land and tenancy reforms by the then government. As compared to the sixties agricultural growth drastically slowed down although there was a sharp recovery toward the end of the seventies. In the second half of the seventies there took place the phenomenon of overseas migration leading to a significant outflow of the labour force and large inflows of foreign remittances. These factors could have had an important impact on the extent and trend in rural poverty in the seventies