48 research outputs found

    Technology Implications of UWB on Wireless Sensor Network-A detailed Survey

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    In today’s high tech “SMART” world sensor based networks are widely used. The main challenge with wireless-based sensor networks is the underneath physical layer. In this survey, we have identified core obstacles of wireless sensor network when UWB is used at PHY layer. This research was done using a systematic approach to assess UWB’s effectiveness (for WSN) based on information taken from various research papers, books, technical surveys and articles. Our aim is to measure the UWB’s effectiveness for WSN and analyze the different obstacles allied with its implementation. Starting from existing solutions to proposed theories. Here we have focused only on the core concerns, e.g. spectrum, interference, synchronization etc.Our research concludes that despite all the bottlenecks and challenges, UWB’s efficient capabilities makes it an attractive PHY layer scheme for the WSN, provided we can control interference and energy problems. This survey gives a fresh start to the researchers and prototype designers to understand the technological concerns associated with UWB’s implementatio

    Adoption features and approach for UWB Wireless Sensor Network based on Pilot Signal assisted MAC

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    In the field of wireless sensor network (WSN), Pilot Assisted Transmission (PAT) is a new concept. In our previous research, a mac layer algorithm called, “PA-MAC” was designed, which exclusively uses PAT technique for the medium access control. The performance of PA-MAC was evaluated under multi-hop and single hop WSNs. It was excellent under a single hop structure (i.e. network with a few nodes). But when it was evaluated for the dense network topology, the performance seriously declined. It was noted that the two main reasons of performance degradation are interference and transmission range. Technically there are two ways to tackle a dense network traffic problem. One is to use the multi-hop structure and the other one is clustering. In this research paper, clustering based adoption strategy is examined, and beside dynamic clustering approach multiple optimization features (i.e., clustering formation based on transmission range, dynamic cluster head selection and use of the Volterra code for the mitigation of interference) are added and tested. Collectively these adoption features have not only improved the media access performance but also optimized the network lifetime.In the field of wireless sensor network (WSN), Pilot Assisted Transmission (PAT) is a new concept. In our previous research, a mac layer algorithm called, “PA-MAC” was designed, which exclusively uses PAT technique for the medium access control. The performance of PA-MAC was evaluated under multi-hop and single hop WSNs. It was excellent under a single hop structure (i.e. network with a few nodes). But when it was evaluated for the dense network topology, the performance seriously declined. It was noted that the two main reasons of performance degradation are interference and transmission range. Technically there are two ways to tackle a dense network traffic problem. One is to use the multi-hop structure and the other one is clustering. In this research paper, clustering based adoption strategy is examined, and beside dynamic clustering approach multiple optimization features (i.e., clustering formation based on transmission range, dynamic cluster head selection and use of the Volterra code for the mitigation of interference) are added and tested. Collectively these adoption features have not only improved the media access performance but also optimized the network lifetime

    Response of fibre metal laminates to blast loading

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    Fibre-metal laminates (FMLs) are hybrid structures comprising interleaved metal sheets and fibre reinforced polymer composites. In this work the performance of fibre metal laminated plates under blast loading is studied numerically. The FML panels are made of alternating layers of aluminium and glass fibre/polypropylene (GFRP) with different number of layers of aluminium and composite and in the panels with equal number of layers, with different thicknesses of GFPP. The panels are subjected to global blast loading uniformly distributed over the surface of the panel and to local blast loading applied at the centre of the panel with a spatial exponential decay towards the edges. The displacements of the front and back faces are found to increase linearly with increasing impulse. The results for global blast loading are correlated with experimental results obtained by Langdon et.al [doi:10.1016/j.euromechsol.2007.09.003] and for localised blast loading with experimental studies conducted by Langdon et.al [doi:10.1016/j.ijimpeng.2006.05.008 , doi:10.1016/j.ijimpeng.2006.05.009]. A good correlation between the experimental and numerical results is found. Back face debonding is found in all the panels for both load cases. The results are also compared with the response of mild and armour steel plates having the same areal densities as FML panels. It has been shown that for the same impulse, the displacement of mild steel plate with the same areal density is approximately twice the back face displacement of FML for global blast and depends upon the thickness of mild steel plate. Therefore, for global blast loading FML performs better and can withstand higher impulses without rupture whereas mild steel plate tears apart for global blast loading and in certain cases for local blast loading. On the other hand, the displacements in armour steel are 70% to 80% of the corresponding FML panel with same areal density when subjected to global or local blast loading

    Impact of Human Resources Management Practices on Turnover, Productivity and Corporate Financial Performance

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    In developing countries, the human resource availability is quite easy but the most unfortunate part is its effective and efficient management. It is a well established fact that it is human beings behind the machines which can drive or drown the organizations. Human behavior and psychology is driven and motivated by varying degree of factors. The researchers across the globe have evolved and successfully practiced certain HRM techniques in order to achieve best performance and productivity from human capital. Unfortunately this area remained neglected and human resource could not be exploited to its full potential in Pakistan despite the fact that the country possesses  one of the best human capital in the world. This paper is an Endeavour to identify the best Human Resource Management practices applicable to Pakistani environments and analyze their positive effects on labor turnover, productivity and corporate financial performance. In order to achieve this objective, a survey questionnaire was designed and disseminated among respondents. A total of 200 questionnaires were distributed, out of which 145 completed questionnaires were received. The authors analyzed the data by using statpro software. the major conclusions and findings were; Need for articulation of vision, mission and values for organization, lack of performance management system, lack of benefit and compensation program, issue of corporate loyalty, poor workforce alignment, absence of HR development and training programs, lack of Human Resource Information System(HRIS),and non adoption of TQM. Keywords: HRM, Productivity, Pakistan, Turnover

    Combined experimental and theoretical study of poly(aniline-co-pyrrole) oligomer

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    Quantum mechanical calculations are performed to establish the structure of an oligomer of aniline and pyrrole [Poly(Ani-co-Py)], through comparison of experimental and theoretically calculated properties, including conductivity. The copolymer was synthesized through chemical oxidative polymerization and then confirmed from the experimental IR, UV-vis, mass spectra, elemental, XRD, TGA, and SEM analysis. Quantum mechanical calculations are performed at Density Functional Theory (DFT) and Time dependent DFT (TD-DFT) methods for the electronic and spectroscopic properties of the oligomer. A very nice correlation is found between the theory and experiment which consequences the structure of Poly(Ani-co-Py). Poly(Ani-co-Py) is not explored like other conducting polymers; however, by tuning this molecular structure, the electro-active nature of this material can be enhanced adequately

    Total parotidectomy under local anesthesia: A novel technique

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    Parotidectomy is a common procedure usually done for a parotid mass necessitating a histological diagnosis. Operation is normally performed under General anesthesia with a nerve stimulator to facilitate facial nerve stimulation. We describe a new technique with reports of three cases, making total parotidectomy under local anesthesia possible. The ascending cervical branch of cervical plexus and the auriculotemporal nerve were anesthetized by bupivacaine 0.25% (2mg/kg) and lignocaine with adrenaline 7 mg/kg. Effective onset of anesthesia was within 15-25 minutes and the operations lasted between 2-3 hours without any complications. This offers advantage in high-risk patients where general anesthesia is contraindicated. The facial nerve can be easily identified with on command movements by the patient rendering the use of nerve stimulator or injection of the dye superfluous. This technique makes total parotidectomy an outpatient procedure and facilitates an early discharge

    Cell proliferation, cell cycle abnormalities, and cancer outcome in patients with Barrett’s esophagus: A long-term prospective study

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    Purpose: Elevated cellular proliferation and cell cycle abnormalities, which have been associated with premalignant lesions, may be caused by inactivation of tumor suppressor genes. We measured proliferative and cell cycle fractions of biopsies from a cohort of patients with Barrett's esophagus to better understand the role of proliferation in early neoplastic progression and the association between cell cycle dysregulation and tumor suppressor gene inactivation. Experimental Design: Cell proliferative fractions (determined by Ki67/DNA multiparameter flow cytometry) and cell cycle fractions (DNA content flow cytometry) were measured in 853 diploid biopsies from 362 patients with Barrett's esophagus. The inactivation status of CDKN2A and TP53 was assessed in a subset of these biopsies in a cross-sectional study. A prospective study followed 276 of the patients without detectable aneuploidy for an average of 6.3 years with esophageal adenocarcinoma as an endpoint. Results: Diploid S and 4N (G2/tetraploid) fractions were significantly higher in biopsies with TP53 mutation and LOH. CDKN2A inactivation was not associated with higher Ki67-positive, diploid S, G1, or 4N fractions. High Ki67-positive and G1 phase fractions were not associated with the future development of esophageal adenocarcinoma (p=0.13 and p=0.15, respectively), while high diploid S phase and 4N fractions were (p=0.03 and p<0.0001, respectively). Conclusions: High Ki67-positive proliferative fractions were not associated with inactivation of CDKN2A and TP53 or future development of cancer in our cohort of patients with Barrett's esophagus. Bi-allelic inactivation of TP53 was associated with elevated 4N fractions, which have been associated with the future development of esophageal adenocarcinoma

    Study protocol of DIVERGE, the first genetic epidemiological study of major depressive disorder in Pakistan

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    INTRODUCTION: Globally, 80% of the burdenof major depressive disorder (MDD) pertains to low- and middle-income countries. Research into genetic and environmental risk factors has the potential to uncover disease mechanisms that may contribute to better diagnosis and treatment of mental illness, yet has so far been largely limited to participants with European ancestry from high-income countries. The DIVERGE study was established to help overcome this gap and investigate genetic and environmental risk factors for MDD in Pakistan. METHODS: DIVERGE aims to enrol 9000 cases and 4000 controls in hospitals across the country. Here, we provide the rationale for DIVERGE, describe the study protocol and characterise the sample using data from the first 500cases. Exploratory data analysis is performed to describe demographics, socioeconomic status, environmental risk factors, family history of mental illness and psychopathology. RESULTS AND DISCUSSION: Many participants had severe depression with 74% of patients who experienced multiple depressive episodes. It was a common practice to seek help for mental health struggles from faith healers and religious leaders. Socioeconomic variables reflected the local context with a large proportion of women not having access to any education and the majority of participants reporting no savings. CONCLUSION: DIVERGE is a carefully designed case-control study of MDD in Pakistan that captures diverse risk factors. As the largest genetic study in Pakistan, DIVERGE helps address the severe underrepresentation of people from South Asian countries in genetic as well as psychiatric research

    NSAIDs Modulate CDKN2A, TP53, and DNA Content Risk for Progression to Esophageal Adenocarcinoma

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    BACKGROUND: Somatic genetic CDKN2A, TP53, and DNA content abnormalities are common in many human cancers and their precursors, including esophageal adenocarcinoma (EA) and Barrett's esophagus (BE), conditions for which aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) have been proposed as possible chemopreventive agents; however, little is known about the ability of a biomarker panel to predict progression to cancer nor how NSAID use may modulate progression. We aimed to evaluate somatic genetic abnormalities with NSAIDs as predictors of EA in a prospective cohort study of patients with BE. METHODS AND FINDINGS: Esophageal biopsies from 243 patients with BE were evaluated at baseline for TP53 and CDKN2A (p16) alterations, tetraploidy, and aneuploidy using sequencing; loss of heterozygosity (LOH); methylation-specific PCR; and flow cytometry. At 10 y, all abnormalities, except CDKN2A mutation and methylation, contributed to EA risk significantly by univariate analysis, ranging from 17p LOH (relative risk [RR] = 10.6; 95% confidence interval [CI] 5.2–21.3, p < 0.001) to 9p LOH (RR = 2.6; 95% CI 1.1–6.0, p = 0.03). A panel of abnormalities including 17p LOH, DNA content tetraploidy and aneuploidy, and 9p LOH was the best predictor of EA (RR = 38.7; 95% CI 10.8–138.5, p < 0.001). Patients with no baseline abnormality had a 12% 10-y cumulative EA incidence, whereas patients with 17p LOH, DNA content abnormalities, and 9p LOH had at least a 79.1% 10-y EA incidence. In patients with zero, one, two, or three baseline panel abnormalities, there was a significant trend toward EA risk reduction among NSAID users compared to nonusers (p = 0.01). The strongest protective effect was seen in participants with multiple genetic abnormalities, with NSAID nonusers having an observed 10-y EA risk of 79%, compared to 30% for NSAID users (p < 0.001). CONCLUSIONS: A combination of 17p LOH, 9p LOH, and DNA content abnormalities provided better EA risk prediction than any single TP53, CDKN2A, or DNA content lesion alone. NSAIDs are associated with reduced EA risk, especially in patients with multiple high-risk molecular abnormalities

    Study protocol of DIVERGE, the first genetic epidemiological study of major depressive disorder in Pakistan.

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    INTRODUCTION: Globally, 80% of the burdenof major depressive disorder (MDD) pertains to low- and middle-income countries. Research into genetic and environmental risk factors has the potential to uncover disease mechanisms that may contribute to better diagnosis and treatment of mental illness, yet has so far been largely limited to participants with European ancestry from high-income countries. The DIVERGE study was established to help overcome this gap and investigate genetic and environmental risk factors for MDD in Pakistan. METHODS: DIVERGE aims to enrol 9000 cases and 4000 controls in hospitals across the country. Here, we provide the rationale for DIVERGE, describe the study protocol and characterise the sample using data from the first 500 cases. Exploratory data analysis is performed to describe demographics, socioeconomic status, environmental risk factors, family history of mental illness and psychopathology. RESULTS AND DISCUSSION: Many participants had severe depression with 74% of patients who experienced multiple depressive episodes. It was a common practice to seek help for mental health struggles from faith healers and religious leaders. Socioeconomic variables reflected the local context with a large proportion of women not having access to any education and the majority of participants reporting no savings. CONCLUSION: DIVERGE is a carefully designed case-control study of MDD in Pakistan that captures diverse risk factors. As the largest genetic study in Pakistan, DIVERGE helps address the severe underrepresentation of people from South Asian countries in genetic as well as psychiatric research
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