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Search Results: 1 - 10 of 730 matches for " Usman YOUSAF "
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Role of Surface Roughness during Natural Convection  [PDF]
M. Yousaf, S. Usman
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.33C021

A computational study was performed in a two-dimensional square cavity in the presence of roughness using an algorithm based on mesoscopic method known as Lattice Boltzmann Method (LBM). A single relaxation time Bhatnagar-Gross-Krook (BGK) model of LBM was used to perform numerical study. Sinusoidal roughness elements of dimensionless amplitude of 0.1 were located on both the hot and cold walls of a square cavity. A Newtonian fluid of the Prandtl number (Pr) 1.0 was considered. The range of the Rayleigh (Ra) number explored was from 103 to 106 in a laminar region. Thermal and hydrodynamic behaviors of fluid were studied using sinusoidal roughness elements. Validation of computational algorithm was performed against previous benchmark studies, and a good agreement was found. Average Nu (Nusselt number) has been calculated to observe the effects of the surface roughness on the heat transfer. Results showed that sinusoidal roughness elements considerably affect the thermal and hydrodynamic behaviors of fluid in a square cavity. The maximum reduction in the average heat transfer in the presence of roughness was calculated to be 23.33%.

Usman YOUSAF,Mohsin ALTAF,Majid Mehmood BAGRAM,Haroon HUSSAIN
Management & Marketing , 2012,
Abstract: The higher education scenario in Pakistan has gone through tremendous changes and improvements in the last decade. Competition resulting from a sudden surge in the number of higher education imparting institutions and the active role of Higher Education Commission has increased the pressure on the universities to continuously enhance the quality of educational services being provided by them. The aim of the researchers in this endeavor is to employ decentering in order to assess the quality of services being provided by the universities. The study has used the SERVQUAL tool by Parasuraman, Zeithmal and Berry (1991) on a five point Liker scale in order to gauge the responses of the students. Analysis was conducted on a total of 156 valid questionnaires. The sample included the students of the top five HEC (Higher Education Commission) recognized universities in the twin cities of Islamabad and Rawalpindi. Data was analyzed using Pearson correlation and regression. Factor analysis was also carried out so as to classify the most important dimensions for the students with respect to higher education in Pakistan. Statistical analysis disclosed a positive and significant association between service quality and customer satisfaction. The factor analysis revealed that the most significant dimension with respect to the Pakistan’s higher education sector are the level of management support, responsiveness of the service providers and the adequacy of physical facilities. The study highlights the importance of treating students as valued customers as the competition in the industry along with the regulatory requirements of HEC as well. The service providers need to be provided adequate support and backing of the top management. The physical facilities and the infrastructure must also be adequate enough to meet the growing and ever changing demands of the industry. The current study is the first of its kind that covers the higher education imparting institutions in Pakistan. Further it is suggested that more and more such researchers be conducted periodically in the future with an increased sample size in order to assess quality.
Usman YOUSAF,Mohsin ALTAF,Noman SARWAR,Syed Ali Hassan SHAH
Management & Marketing , 2012,
Abstract: To study the influence of Perceived cost, risk, convenience and enjoyment on online consumer purchases. Being more convenient online shopping seems painless compared to in store shopping, why consumers are still reluctant to shop online?.A sample of 220 questionnaires was filled from different departments at University of Sargodha. Respondents were asked to fill the questionnaire based on four factors (Perceived cost, Perceived risk, Perceived convenience, Perceived enjoyment), there were 2 general questions. Out of 220, 207 questionnaires were returned. One sample test is applied in this study to check the reliability of independent variables. Analysis was also done on basis of gender and their ages. The most important factor out of four, which can persuade the customer's online buying decision, is delivery cost for purchased items and it has negative relationship with dependent variable, moreover perceived risk has also negative relationship with dependent one. Perceived convenience and Perceived enjoyment has positive relationship with online shopping preference. As online shopping is easier to do but due to extra delivery cost and risk factors consumers do not adopt online shopping and these factors should be minimized to promote online shopping. Online shopping should be promoted and to gain the consumer confidence, delivery cost and risk factor should be minimized. As online shopping is easier to do as compared to offline shopping but people still reluctant to use internet for online shopping, so to promote online shopping delivery cost and risk factor should be minimized to gain consumers attraction and confidence. People want to experience online shopping but it won’t be promoted until delivery cost and perceived risk factors be reduced. A little work has been done on exploring the factors that influence the online buying decision. These factors are called situational factors and include delivery charges, risk factors, convenience factors and enjoyment factors. In Pakistan consumers are not too much affiliated to online shopping as compared to European countries and not too much researches have been done related to online shopping in Pakistan , so this research been conducted to promote online shopping.
Entrepreneur as an authentic leader: A study of small and medium sized enterprises in Pakistan
Taimoor Abid,Mohsin Altaf,Usman Yousaf,Mohammad Majid Mehmood Bagram
Management Science Letters , 2012,
Abstract: The aim of this paper is to explore the authentic leadership styles of an entrepreneurs and its impact on employee’s commitment and satisfaction. By using the authentic leadership model, this study seeks to give a tentative test of the connection among employees’ awareness of the business creator as an authentic leader and the employees’ attitudes. Findings are that the opinion of employees’ about authentic leadership serves as the intoxicating analyst of employee job satisfaction and organizational commitment.
Inhibition of HCV 3a genotype entry through Host CD81 and HCV E2 antibodies
Usman A Ashfaq, Muhammad Qasim, Muhammad Z Yousaf, Muhammad Awan, Shah Jahan
Journal of Translational Medicine , 2011, DOI: 10.1186/1479-5876-9-194
Abstract: The present study elaborated the role of CD81 and HCV glycoprotein E2 in HCV entry using retroviral pseudo-particles of 3a local genotype. Our results demonstrated that HCV specific antibody E2 and host antibody CD81 showed dose- dependent inhibition of HCV entry. HCV E2 antibody showed 50% reduction at a concentration of 1.5 ± 1 μg while CD81 exhibited 50% reduction at a concentration of 0.8 ± 1 μg. In addition, data obtained with HCVpp were also confirmed with the infection of whole virus of HCV genotype 3a in liver cells.Our data suggest that HCV specific E2 and host CD81 antibodies reduce HCVpp entry and full length viral particle and combination of host and HCV specific antibodies showed synergistic effect in reducing the viral titer.HCV is a major health problem that infects 350 million people worldwide and 10 million people in Pakistan [1]. HCV infection is mainly restricted to hepatocytes, and since most of the infected individuals fail to spontaneously clear the virus from the liver, this leads to a chronic infection that can evolve towards liver fibrosis, cirrhosis and hepatocellular carcinoma over a period of decades [2]. The current standard therapy is Pegylated interferon and ribavirin, which shows poor tolerability and is only capable of attaining a sustained viral response in half of patients due to resistance mutations, adverse side effects and high cost [3].HCV is a small enveloped virus with a positive-sense, single-stranded RNA genome that encodes a large polyprotein of 3010 amino acids. The polyprotein is co- and post-translationally processed by cellular and virally encoded proteases to produce four structural (Core, E1, E2 and P7) and six non-structural proteins (NS2, NS3, NS4A, NS4B, NS5A, NS5B) [4,5]. Among the structural protein, HCV envelop protein E1 and E2 are highly glycosylated and play an important role in cell entry. HCV NS3 serine protease and NS5b RNA dependent RNA polymerase play an important role in replication. HCV NS3 serine pro
Rabies molecular virology, diagnosis, prevention and treatment
Muhammad Yousaf, Muhammad Qasim, Sadia Zia, Muti ur Rehman Khan, Usman Ashfaq, Sanaullah Khan
Virology Journal , 2012, DOI: 10.1186/1743-422x-9-50
Abstract: The current article mainly covers the genome, virology, symptoms, epidemiology, diagnostic methods, and the high risk countries around the globe.Rabies is a zoonotic (transmitted from animals to human) viral infectious disease. This infection is transmitted to human by the animals already suffering from it. The animals which are mainly reported as causes of rabies are; dogs, raccoons, skunks, bats, and foxes. Rabies or "Hydrophobia" is a disease which makes the dogs sick. In many eastern and western countries dogs are vaccinated against it, but it is not controlled yet. Rabies is caused by a virus that, attacks on the nerves system and later excreted in saliva [1]. A person or animal can become a victim of rabies in many ways including [2],a. Bitesb. Non-bites exposurec. Human to Human TransmissionBites from rabid animal to human are very common but the other two factors are rare [2]. Rabies affects the brain and spinal cord (central nervous system) with initial symptoms like; flu, fever, headache, but the infection can progress quickly to hallucinations, paralysis, and eventually death [3].Rabies virus is the "type species" of the Lyssavirus genus of Rhabdoviridae family. The virus is enveloped and has a single stranded, negative sense RNA genome [4]. The RNA genome of the virus encodes five genes whose order is highly conserved. These genes codes for: nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G), and a viral RNA polymerase (L). All rahbdoviruses have two major structural components; helical ribonucleoprotein core (RNP) and surrounding envelops. The two proteins, P and L are associated with RNP. The glycoprotein forms approximately 400 trimeric spikes, which are tightly arranged on the surface of the virus [5]. The virus nucleoprotein (N) plays critical role in replication and transcription. Both viral transcription and replication are reduced, if the nucleoprotein is not phosphorylated [6]. Rhabdoviruses cell surface receptors are no
siRNAs: Potential therapeutic agents against Hepatitis C Virus
Usman A Ashfaq, Muhammad Z Yousaf, Maida Aslam, Rahat Ejaz, Shah Jahan, Obaid Ullah
Virology Journal , 2011, DOI: 10.1186/1743-422x-8-276
Abstract: HCV infection is a serious global health problem that affects 180 million people worldwide and 10 million people in Pakistan [1]. Hepatitis C virus (HCV) causes acute and chronic hepatitis which can eventually lead to permanent liver damage, hepatocellular carcinoma and death [2]. Of those acutely infected with HCV, around 85% develop chronic infection. Approximately 70% of patients with chronic viremia develop chronic liver disease, 10-20% of which develop liver cirrhosis. It was estimated by the World Health Organization in 2004 that the annual deaths due to liver cancer caused by HCV and cirrhosis were 308,000 and 785,000, respectively [3].HCV is a small enveloped virus with a positive sense, single-stranded RNA genome that encodes a large polyprotein of 3010 amino acids. The polyprotein is co- and posttranslationally processed by cellular and virally encoded proteases to produce four structural (Core, E1, E2 and P7) and six non-structural (NS2, NS3, NS4A, NS4B, NS5A, NS5B) proteins [4,5]. Among the structural protein, HCV envelop protein E1 and E2 are highly glycosylated and play an important part in cell entry. HCV NS3 serine protease and NS5b play an important role in replication. HCV NS3 serine protease, NS5B RNA-dependent RNA polymerase and HCV structural proteins are important targets for antiviral drug development.There are six major and more than 80 subtypes of HCV. This classification is based on nucleotide variation among different HCV isolate. They occur in different proportion in different parts of the world. Genotype 1a and 1b are the most common genotypes in the United States and Europe [6,7]. The most prevalent HCV genotype in Pakistan is 3a followed by 3b and 1a [8].Presently, there is no vaccine available for prevention of HCV infection due to high degree of strain variation. Current therapeutic options for hepatitis C are limited, especially for genotype 1. For genotypes 2 and 3, pegylated interferon in combination with ribavirin, can lead to a
The epidemic of HIV/AIDS in developing countries; the current scenario in Pakistan
Muhammad Z Yousaf, Sadia Zia, Masroor E Babar, Usman A Ashfaq
Virology Journal , 2011, DOI: 10.1186/1743-422x-8-401
Abstract: In the present article we focused current situation of surveillance of HIV/AIDS, its virology, genotype, diagnostics, high-risk groups, reasons of vulnerability in Pakistani population, and the role of different national and international organizations in this situation.HIV belongs to Lentivirus, which are also known as "slow virus". The name indicates there mode of action as they enters into body and remain in it for longer period of time. They have unique property of being inserting the information into the DNA of host cell and also have the ability to replicate in non-dividing cells. Due to these characteristics they are considered to be the most efficient gene delivery vector [1]. HIV infects defense/immune system cells such as CD4+ T cells, macrophages and dendritic cells [2]. The CD4+ cells play a crucial role in the maintenance of immune system. After infection, HIV uses CD4+ cells as host to make copies and infect other cells. This leads to the reduction of CD4+ cells in body and immune system totally collapse [3]. The development from HIV to AIDS is checked by the rapid decline of CD4+ cells [3].Two types of HIV has been characterized; HIV-1 and HIV-2. HIV-1 is the most virulent and pathogenic strain. Worldwide, the predominant virus is HIV-1, and generally when people refer to HIV without specifying the type of virus they will be referring to HIV-1. The relatively uncommon HIV-2 type is concentrated in West Africa and is rarely found elsewhere. The reason behind is that HIV-2 weaken the immune system slowly than HIV-1 [4]. The HIV-1 is further divided into 4-groups; a) major group M, b) Outlier group O, c) Group N, d) Group P. These groups have been identified in there envelop region. Group M is further divided in to A, B, C, D, F, G, H, J and K. in Asian countries B and C are the predominant clades of HIV-1. But in Pakistan HIV-1 is dominant in Pakistan as compare to other clades, this was found more in IDUs in Karachi [5]. HIV-2 has also 8 clades from A
Underrepresentation of Women at Academic Excellence and Position of Power: Role of Harassment and Glass Ceiling  [PDF]
Rizwana Yousaf, Rudi Schmiede
Open Journal of Social Sciences (JSS) , 2016, DOI: 10.4236/jss.2016.42023
Abstract: The study intends to comprehend the underrepresentation of women on positions of power and academic excellence in academia. The study explained the role of exploitation and harassment, which might hinder, when women were trying to climb to top hierarchical position. The majority of women supervised by male heads, sexual harassment could be used as a glass ceiling to hamper women to reach top hierarchal level. The majority participants were working on lower academic and administrative hierarchy; they were experiencing harassment throughout the hierarchical level. Similarly, they considered that harassment could contribute to the underrepresentation of women at academic excellence and a position of power.
Harassment Act Implementation in Higher Education Institutions  [PDF]
Rizwana Yousaf, Rudi Schmiede
Open Journal of Leadership (OJL) , 2016, DOI: 10.4236/ojl.2016.51002
Abstract: Effective implementation of harassment Act might be inevitable to acquiring gender equality in higher education institutions and diminishing the influence of patriarchal and conservative mind set. This study intended to explore implementation of the harassment Act (2010) in universities. Although Government of Pakistan has enforced harassment Act and Higher Education Commission (HEC) made it mandatory to implement, none of the university in the sample has implemented it. Various incidence of harassment has been reported by study participants and in certain cases, victims are asked to resign the jobs as they refuse or fail to comply with the drives of male colleagues and heads. Lack of state and organizational control leads women to be silent and tolerant of harassment and ultimately, it encourages perpetrator to continue the derogatory behaviour.
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