2,871 research outputs found

    Characteristics of smokers and their knowledge about smoking at a teaching hospital in Karachi

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    Objective: To study the characteristics of smokers and their knowledge about smoking, among Family Practice Patients, at a teaching hospital in Karachi, Pakistan. Main outcome measures: Age at starting smoking, duration and number of cigarettes smoked, started smoking under influence of friends, colleagues, family members or self motivation, number of friends and colleagues who smoked, whether smoking is unhealthy, and actual chance of harm to an individual due to smoking is very rare or not. Results: One hundred patients who visited Family Practice Center were interviewed. Sixty one percent were young married men, well educated and either student, in private service, self employed or unemployed. Eighty-four (84%) smokers started smoking between 16-25 years of age, and smoked 6-20 cigarettes daily for two to twenty five years. Sixty-nine (69%) of them started smoking under the influence of friends and had 3-5 friends and colleagues who smoked. 91% of smokers believed that smoking is unhealthy and were aware that it causes lung cancer and heart disease. Majority of them (69%) believed that the actual harm of smoking to an individual is not very rare. Conclusion: We have documented the characteristics of smokers and their knowledge about smoking among Family Practice patients. Majority of the respondents started smoking at a young age under the influence of friends though they were aware of its harmful effects. Though the sample size is small but it does give an indication about the responsible factors to plan interventional preventive strategies

    Charging induced asymmetry in molecular conductors

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    We investigate the origin of asymmetry in various measured current-voltage (I-V) characteristics of molecules with no inherent spatial asymmetry, with particular focus on a recent break junction measurement. We argue that such asymmetry arises due to unequal coupling with the contacts and a consequent difference in charging effects, which can only be captured in a self-consistent model for molecular conduction. The direction of the asymmetry depends on the sign of the majority carriers in the molecule. For conduction through highest occupied molecular orbitals (i.e. HOMO or p-type conduction), the current is smaller for positive voltage on the stronger contact, while for conduction through lowest unoccupied molecular orbitals (i.e. LUMO or n-type conduction), the sense of the asymmetry is reversed. Within an extended Huckel description of the molecular chemistry and the contact microstructure (with two adjustable parameters, the position of the Fermi energy and the sulphur-gold bond length), an appropriate description of Poisson's equation, and a self-consistently coupled non-equilibrium Green's function (NEGF) description of transport, we achieve good agreement between theoretical and experimental I-V characteristics, both in shape as well as overall magnitude.Comment: length of the paper has been extended (4 pages to 6 pages), two new figures have been added (3 figures to 5 figures), has been accepted for PR

    The FMOS-Cosmos Survey of Star-Forming Galaxies at z ~ 1.6 II. The Mass-Metallicity Relation and the Dependence on Star Formation Rate and Dust Extinction

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    We investigate the relationships between stellar mass, gas-phase oxygen abundance (metallicity), star formation rate (SFR), and dust content of star-forming galaxies at z ~ 1.6 using Subaru/FMOS spectroscopy in the COSMOS field. The mass-metallicity (MZ) relation at z ~ 1.6 is steeper than the relation observed in the local universe. The steeper MZ relation at z ~ 1.6 is mainly due to evolution in the stellar mass where the MZ relation begins to turnover and flatten. This turnover mass is 1.2 dex larger at z ~ 1.6. The most massive galaxies at z ~ 1.6 (~10^(11) M_☉) are enriched to the level observed in massive galaxies in the local universe. The MZ relation we measure at z ~ 1.6 supports the suggestion of an empirical upper metallicity limit that does not significantly evolve with redshift. We find an anti-correlation between metallicity and SFR for galaxies at a fixed stellar mass at z ~ 1.6, which is similar to trends observed in the local universe. We do not find a relation between stellar mass, metallicity, and SFR that is independent of redshift; rather, our data suggest that there is redshift evolution in this relation. We examine the relation between stellar mass, metallicity, and dust extinction, and find that at a fixed stellar mass, dustier galaxies tend to be more metal rich. From examination of the stellar masses, metallicities, SFRs, and dust extinctions, we conclude that stellar mass is most closely related to dust extinction

    Metallicity gradients in local field star-forming galaxies: Insights on inflows, outflows, and the coevolution of gas, stars and metals

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    We present metallicity gradients in 49 local field star-forming galaxies. We derive gas-phase oxygen abundances using two widely adopted metallicity calibrations based on the [OIII]/Hbeta, [NII]/Halpha and [NII]/[OII] line ratios. The two derived metallicity gradients are usually in good agreement within +/-0.14 dex/R25 (R25 is the B-band iso-photoal radius), but the metallicity gradients can differ significantly when the ionisation parameters change systematically with radius. We investigate the metallicity gradients as a function of stellar mass (8<log(M*/Msun)<11) and absolute B-band luminosity (-16 > MB > -22). When the metallicity gradients are expressed in dex/kpc, we show that galaxies with lower mass and luminosity, on average, have steeper metallicity gradients. When the metallicity gradients are expressed in dex/R25, we find no correlation between the metallicity gradients, and stellar mass and luminosity. We provide a local benchmark metallicity gradient of field star-forming galaxies useful for comparison with studies at high redshifts. We investigate the origin of the local benchmark gradient using simple chemical evolution models and observed gas and stellar surface density profiles in nearby field spiral galaxies. Our models suggest that the local benchmark gradient is a direct result of the coevolution of gas and stellar disk under virtually closed-box chemical evolution when the stellar-to-gas mass ratio becomes high (>>0.3). These models imply low current mass accretion rates (<0.3xSFR), and low mass outflow rates (<3xSFR) in local field star-forming galaxies.Comment: 25 pages, 21 figures, accepted to MNRA

    The role of transformational leadership on firm performance: mediating effect of corporate sustainability and moderating effect of knowledge-sharing

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    The primary purpose of the research is to investigate the mediating role of corporate sustainability in the relationship between the impacts of transformational leadership on the performance of firms. This study also aimed to investigate the moderating role of knowledge-sharing on the relationship of transformational leadership with corporate sustainability. Respondents of the study were the top management of large Chinese automobile sectors, such as Shanghai Automotive Business Corporation (Group), China FAW Group Corporation, Dongfeng Motor Co., Ltd., Beijing Automotive Group Co., Ltd., and China North Industries Group Corporation. These are the companies with the biggest market share in the automobile manufacturing industry in China. The data was gathered by using a self-administrative survey questionnaire from 198 individuals operating in different automobile industries in different sectors of China. The data were analyzed using structural equation modeling (SEM) through the Smart PLS 3.3.2 software. The results of this study revealed that transformational leadership has a positive and significant effect on the performance of the firm. Corporate sustainability has a significant positive mediating role in the association of transformational leadership and firm performance. Findings indicated that knowledge-sharing also has a positive moderating role in the association between transformational leadership and firm performance. The findings of this study contribute to the body of knowledge and show that leadership style has a significant effect on firm performance and that knowledge-sharing culture in firms is essential for better performance of the firm. Furthermore, firms may improve their performance by improving their sustainability and by creating knowledge-sharing culture. The findings are important, particularly in connection with a developed country like China. The findings have important insights for various stakeholders, i.e., government, regulatory bodies, practitioners, academia, industry, and researchers

    Incoherent Transport through Molecules on Silicon in the vicinity of a Dangling Bond

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    We theoretically study the effect of a localized unpaired dangling bond (DB) on occupied molecular orbital conduction through a styrene molecule bonded to a n++ H:Si(001)-(2x1) surface. For molecules relatively far from the DB, we find good agreement with the reported experiment using a model that accounts for the electrostatic contribution of the DB, provided we include some dephasing due to low lying phonon modes. However, for molecules within 10 angstrom to the DB, we have to include electronic contribution as well along with higher dephasing to explain the transport features.Comment: 9 pages, 5 figure

    Cutting Tools in Finishing Operations for CNC Rapid Manufacturing Processes: Experimental Studies

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    This paper reports an advanced approach in the application of CNC machining for rapid manufacturing processes (CNC-RM). The aim of this study is to improve the quality of machined parts by introducing different cutting tools during finishing operations. As the cutting is performed in different directions, the surfaces presented on part can be classified into several categories. Therefore, suitable cutting tools are assigned to machine particular surfaces and to improve the quality. Experimental studies have been carried out by fabricating several parts based on the suggested approach. The results provide further support for implementing this approach in rapid machining processes

    Cutting Tools in Finishing Operations for CNC Rapid Manufacturing Processes: Experimental Studies

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    This paper reports an advanced approach in the application of CNC machining for rapid manufacturing processes (CNC-RM). The aim of this study is to improve the quality of machined parts by introducing different cutting tools during finishing operations. As the cutting is performed in different directions, the surfaces presented on part can be classified into several categories. Therefore, suitable cutting tools are assigned to machine particular surfaces and to improve the quality. Experimental studies have been carried out by fabricating several parts based on the suggested approach. The results provide further support for implementing this approach in rapid machining processes

    Oocyte Development of Scalloped Perchlet, Ambassis Nalua (Hamilton 1822)

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    Ikan seriding (Ambassis nalua) merupakan salah satu jenis ikan di perairan Teluk Pabean, Indramayu yang berukuran kecil, transparan dan tersedia dalam jumlah melimpah. Penelitian ini bertujuan untuk melihat perkembangan sel telur secara histologis dan menentukan tipe pemijahan ikan seriding. Ikan seriding didapatkan dari hasil tangkapan nelayan di Teluk Pabean, kemudian gonad contoh diawetkan dengan menggunakan larutan BNF (Buffer Neutral Formalin). Preparat histo-logis sel telur dibuat dengan metode pewarnaan HE, kemudian diamati dibawah mikroskop berkamera. Tahapan perkembangan oosit pada ikan seriding yaitu kromatin nukleus dan perinuklear (tahap pertumbuhan awal), kortikal alveoli, vitelo-genesis, dan pematangan. Tahapan tersebut menunjukkan bahwa ikan seriding merupakan tipe ikan yang memijah secara bertahap
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