5,258 research outputs found

    Resolvability in Hypergraphs

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    This article emphasizes an extension of the study of metric and par- tition dimension to hypergraphs. We give a sharp lower bounds for the metric and partition dimension of hypergraphs in general and give exact values under specified conditions.eral and give exact values with specified conditions

    Catalytic upgrading of hydrothermal liquefaction biocrudes: Different challenges for different feedstocks

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    Hydrothermal liquefaction (HTL) followed by catalytic hydrotreating of the produced biocrude is increasingly gaining ground as an effective technology for the conversion of biomass into liquid biofuels. A strong advantage of HTL resides in its great flexibility towards the feedstock, since it is able to treat a large number of different organic substrates, ranging from dry to wet residual biomass. Nevertheless, the characteristics of biocrudes from different typologies of organic materials result in different challenges to be met during the hydrotreating step, leading to differences in heteroatoms removal and in the typology and composition of the targeted products. In this work, biocrudes were catalytically hydrotreated with a commercial NiMo/Al2O3 catalyst at different temperatures and pressures. Sewage sludge biocrude was found to be very promising for the production of straight-chain hydrocarbons in the diesel range, with considerable heteroatoms removal even at mild hydrotreating conditions. Similar results were shown by algal biocrude, although complete denitrogenation is challenging. Upgraded biocrudes from lignocellulosic feedstock (miscanthus) showed high yields in the gasoline range, with a remarkable content of aromatics. Operating at a higher H2 pressure was found to be crucial to prevent coking and decarboxylation reactions.Comment: Accepted manuscript for publication in Renewable Energ

    Robustness of geography as an instrument to assess impact of climate change on agriculture

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    The empirical literature on climate change and agriculture does not adequately address the issue of potential endogeneity between climatic variables and agriculture which makes their estimates unreliable. This study is designed to investigate the relationships between climate change and agriculture and test the potential reverse causality and endogeneity of climatic variables to agriculture. This study introduces a geographical instrument, longitude and latitude, for temperature to assess the impact of climate change on agriculture by estimating regression using IV-2SLS method over annual panel data for 60 countries for the period 1999-2011. The Identification and F-statistic tests are used to choose and exclude the instrument. The inclusion of some control variables is supposed to reduce the omitted variable bias. The study finds a negative relationship between temperature and agriculture. Surprisingly the magnitude of the coefficient on temperature is mild, at least 20%, as compared to previous studies may be due to the use of the instrumental variable which is also supported by an alternative robust measure when estimated across different regions. The study provides strong implications for the policy makers to confront climate change that is an impending danger to agriculture. In designing effective policies and strategies policy makers should focus not only on crop production but also on other agricultural activities such as livestock production and fisheries, in addition to national and international socio-economic and geopolitical dynamics. This paper contributes to the growing literature in at least four aspects. First, empirical settings introduce an innovative geographical instrument, Second, it includes a wider set of control variables in the analysis. Third, improves over previous researches by using agriculture value addition and finally, the effects of temperature and precipitation on a single aggregate measure, agriculture value addition are separately investigated

    Gender difference in age at onset of schizophrenia: a cross sectional study from Pakistan

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    OBJECTIVE: To validate the effect of gender on age at onset of schizophrenia in a developing country METHODS: Medical records of 252 patients diagnosed with schizophrenia according to DSM-IV criteria at a tertiary care hospital in Karachi, Pakistan between 2002 and 2008 were reviewed using a structured questionnaire. Age at onset was defined as age at onset of psychotic symptoms, age at first contact with a health care provider and age at first hospitalization. Socio-demographic variables were reported using descriptive statistics and all measures of age at onset were compared across gender using t-test. RESULTS: There were 119 women and 133 men with mean age of 37.6 +/- 12.8 years. All three measures of age at onset of illness showed no difference between women and men. The mean age when first psychotic symptoms appeared in men was 24.86 +/- 8.83 years (n = 128) while that in women was 26.57 +/- 9.96 years (n = 111), p = 0.160. The mean age at index hospitalization for treatment of psychosis in men was 29.50 +/- 10.64 years (n = 123) and in women was 31.61 +/- 12.07 years (n = 103), p = 0.164. The mean age at first contact with any caregiver in men was 29.73 +/- 37.58 years (n = 119) and in women was 29.38 +/- 11.99 years (n = 108), p = 0.926. CONCLUSION: There is no significant difference in age at onset of schizophrenia across gender in our population. This validates a difference in epidemiology of schizophrenia in the South Asian population

    Teaching paediatric critical care medicine to paediatric residents

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    Critical care training during paediatric residency provides an ideal opportunity to learn and refine the skills needed in the early recognition and prompt treatment of the acutely ill paediatric patients. Paediatric critical care medicine is a relatively young sub-specialty in Pakistan. The aim of this study is to describe our experience of teaching paediatric residents in paediatric critical care medicine during paediatric intensive care unit rotation. Our paediatric critical care teaching curriculum for residents is based on the spectrum of our common critical care problems along with basic principal of critical care. The clinical rotation in our paediatric intensive care unit is very dynamic, thrilling, enjoyable and provides a lot of learning opportunities. During the rotation, the residents were exposed to all major critical care illnesses in infants and children. We use four traditional models of learning in our Paediatric Intensive Care Unit (PICU): bedside rounds, direct patient care, didactic learning and self-study. Our curriculum enhances the resident\u27s educational and clinical experience of paediatric intensive care medicine

    Human-Centric Cyber Social Computing Model for Hot-Event Detection and Propagation

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Microblogging networks have gained popularity in recent years as a platform enabling expressions of human emotions, through which users can conveniently produce contents on public events, breaking news, and/or products. Subsequently, microblogging networks generate massive amounts of data that carry opinions and mass sentiment on various topics. Herein, microblogging is regarded as a useful platform for detecting and propagating new hot events. It is also a useful channel for identifying high-quality posts, popular topics, key interests, and high-influence users. The existence of noisy data in the traditional social media data streams enforces to focus on human-centric computing. This paper proposes a human-centric social computing (HCSC) model for hot-event detection and propagation in microblogging networks. In the proposed HCSC model, all posts and users are preprocessed through hypertext induced topic search (HITS) for determining high-quality subsets of the users, topics, and posts. Then, a latent Dirichlet allocation (LDA)-based multiprototype user topic detection method is used for identifying users with high influence in the network. Furthermore, an influence maximization is used for final determination of influential users based on the user subsets. Finally, the users mined by influence maximization process are generated as the influential user sets for specific topics. Experimental results prove the superiority of our HCSC model against similar models of hot-event detection and information propagation

    Emotional Intelligence and Personal Development in Employees: a Case Study of Zigron Corporation, Pakistan

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    Article sought to explore the potential role of Emotional Intelligence (EI) in the personal development of organizational employees and to find out the scope of emotional intelligence for personal development of individuals. This study was qualitative in nature; however, to ensure the authenticity and generalizability of the results some quantitative analysis analyses were applied. Using case study method and taking interviews from 17 software house engineers of Zigron Corporation in Pakistan, this study suggests that emotional intelligence plays a crucial role in the personal development of individuals
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