3,357 research outputs found

    ANTECEDENTS AND IMPACT OF INTERNET ADDICTION AMONG INDIAN COLLEGE STUDENTS IN KERALA, INDIA

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    The present generation of Indian adolescents relies heavily on the Internet which has become an integral part of every Indian college student’s daily routine. As with other developing countries, adolescents and college students in India are dependent on the Internet for both educational and non-educational purposes. Not surprisingly then, Internet addiction has become an increasingly serious societal problem but one which unfortunately has attracted little or no research interest within the Indian context. The present study has been designed to address this issue by investigating how Internet addiction-related behaviors may vary as a function of Indian college students’ perception of their parents’ parenting styles and their emotive states (depression, anxiety, stress), and subsequently, how such Internet addiction-related behaviors may influence their well-being (psychological well-being, loneliness, and academic performance). Overall, the findings from the present study indicate that the parenting styles of mothers and fathers in Kerala, India have differential influences on their children’s psychological well-being, academic performance, and loneliness. The implications of these findings are discussed with reference to the cultural nuances and parameters that circumscribe the Indian college student’s family life

    Flow-Induced Voltage Generation Over Monolayer Graphene in the Presence of Herringbone Grooves

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    While flow-induced voltage over a graphene layer has been reported, its origin remains unclear. In our previous study, we suggested different mechanisms for different experimental configurations: phonon dragging effect for the parallel alignment and an enhanced out-of-plane phonon mode for the perpendicular alignment (Appl. Phys. Lett. 102:063116, 2011). In order to further examine the origin of flow-induced voltage, we introduced a transverse flow component by integrating staggered herringbone grooves in the microchannel. We found that the flow-induced voltage decreased significantly in the presence of herringbone grooves in both parallel and perpendicular alignments. These results support our previous interpretation

    Temperature Controlled Packaging Container for Biologics and Pharmaceuticals

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    Clinical Supplies Management, Inc. (CSM) provides clinical trial services to biotechnology and pharmaceutical companies by shipping pharmaceuticals to clinics and other patients. In winter 2014, CSM presented a temperature control packaging project to the Cal Poly Senior Project class. As a result, three Cal Poly Mechanical Engineering Students were tasked to design, manufacture, and qualify a shipping container that would maintain ten 10 mL vials between 2-8°C for 96 hours. The final product would have to cost less to ship than the Credo Cube, CSM’s current temperature control packaging product. After considerable research and analysis on possible temperature control technologies, it was determined that the most reliable and economical solution was similar technology to the Credo Cube. The main features of the product are as follows: Vacuum Insulated Paneling (VIP) is used as a thermal resistor to reduce the heat transfer from the surroundings to the payload Phase change material (PCM) maintains the desired payload temperature An optimization for the specified payload was performed by creating designs to reduce the tare weight, and dimensional weight using the above technologies. During the manufacturing phase, the selected vendor for phase change material was unwilling to accommodate a lead time within the senior project’s scope. This was believed to be partially due to the low volume and direct competition of the potential product. CSM was in contact with the vendor, and it was decided that the legal steps needed to move forward with the selected PCM would be too far outside of the project’s scope. Consequently, it was decided between the project team and CSM that using water as a prototype PCM was acceptable. Instead of a final product, a proof of concept prototype and a calculator that would help CSM redesign the product if other VIP or PCM were to be pursued in the future acted as the final deliverables. Although the prototype was not able to maintain temperature within range for 96 hours, the design can easily be scaled to do so with further testing and the use of the provided calculator. The following report details the design, manufacture, and qualification of the shipping container prototype

    Phase transition of surface models with intrinsic curvature

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    It is reported that a surface model of Polyakov strings undergoes a first-order phase transition between smooth and crumpled (or branched polymer) phases. The Hamiltonian of the model contains the Gaussian term and a deficit angle term corresponding to the weight of the integration measure dX in the partition function.Comment: 6 pages with 7 figures, Eur. Phys. J. B (in press

    The effects of short-term omission of daily medication on the pathophysiology of heart failure

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    Aims Pharmacological therapies for heart failure (HF) aim to improve congestion, symptoms, and prognosis. Failing to take medication is a potential cause of worsening HF. Characterizing the effects of short-term medication omission could inform the development of better technologies and strategies to detect and interpret the reasons for worsening HF. We examined the effect of planned HF medication omission for 48 h on weight, echocardiograms, transthoracic bio-impedance, and plasma concentrations of NT-proBNP. Methods and results Outpatients with stable HF and an LVEF <45% were assigned to take or omit their HF medication for 48 h in a randomized, crossover trial. Twenty patients (16 men, LVEF 32 ± 9%, median NT-proBNP 962 ng/L) were included. Compared with regular medication, omission led to an increase in NT-proBNP by 99% (from 962 to 1883 ng/L, P < 0.001), systolic blood pressure by 16% (from 131 to 152 mmHg, P < 0.001), and left atrial volume by 21% (from 69 to 80 mL, P = 0.001), and reductions in transthoracic bio-impedance by 10% (from 33 to 30 Σ, P = 0.001) and serum creatinine by 8% (from 135 to 118 µmol/L, P = 0.012). No significant changes in body weight, heart rate, or LVEF were observed. Conclusions The characteristic pattern of response to short-term medication omission is of increasing congestion but, in contrast to the pattern reported for disease progression, with a rise in blood pressure and improved renal function. In stable HF, weight is not a sensitive marker of short-term diuretic omission

    Using Bars As Signposts of Galaxy Evolution at High and Low Redshifts

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    An analysis of the NICMOS Deep Field shows that there is no evidence of a decline in the bar fraction beyond z~0.7, as previously claimed; both bandshifting and spatial resolution must be taken into account when evaluating the evolution of the bar fraction. Two main caveats of this study were a lack of a proper comparison sample at low redshifts and a larger number of galaxies at high redshifts. We address these caveats using two new studies. For a proper local sample, we have analyzed 134 spirals in the near-infrared using 2MASS (main results presented by Menendez-Delmestre in this volume) which serves as an ideal anchor for the low-redshift Universe. In addition to measuring the mean bar properties, we find that bar size is correlated with galaxy size and brightness, but the bar ellipticity is not correlated with these galaxy properties. The bar length is not correlated with the bar ellipticity. For larger high redshift samples we analyze the bar fraction from the 2-square degree COSMOS ACS survey. We find that the bar fraction at z~0.7 is ~50%, consistent with our earlier finding of no decline in bar fraction at high redshifts.Comment: In the proceedings of "Penetrating Bars through Masks of Cosmic Dust: The Hubble Tuning Fork strikes a New Note

    Stromal-Cell-Derived Factor-1 (SDF-1)/CXCL12 as Potential Target of Therapeutic Angiogenesis in Critical Leg Ischaemia

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    In the Western world, peripheral vascular disease (PVD) has a high prevalence with high morbidity and mortality. In a large percentage of these patients, lower limb amputation is still required. Studies of ischaemic skeletal muscle disclosed evidence of endogenous angiogenesis and adaptive skeletal muscle metabolic changes in response to hypoxia. Chemokines are potent chemoattractant cytokines that regulate leukocyte trafficking in homeostatic and inflammatory processes. More than 50 different chemokines and 20 different chemokine receptors have been cloned. The chemokine stromal-cell-derived factor-1 (SDF-1 aka CXCL12) is a constitutively expressed and inducible chemokine that regulates multiple physiological processes, including embryonic development and organ homeostasis. The biologic effects of SDF-1 are mediated by chemokine receptor CXCR4, a 352 amino acid rhodopsin-like transmembrane-specific G protein-coupled receptor (GPCR). There is evidence that the administration of SDF-1 increases blood flow and perfusion via recruitment of endothelial progenitor cells (EPCs). This review will focus on the role of the SDF-1/CXCR4 system in the pathophysiology of PVD and discuss their potential as therapeutic targets for PVD

    A celestial gamma-ray foreground due to the albedo of small solar system bodies and a remote probe of the interstellar cosmic ray spectrum

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    We calculate the gamma-ray albedo flux from cosmic-ray (CR) interactions with the solid rock and ice in Main Belt asteroids (MBAs), Jovian and Neptunian Trojan asteroids, and Kuiper Belt objects (KBOs) using the Moon as a template. We show that the gamma-ray albedo for the Main Belt, Trojans, and Kuiper Belt strongly depends on the small-body size distribution of each system. Based on an analysis of the Energetic Gamma Ray Experiment Telescope (EGRET) data we infer that the diffuse emission from the MBAs, Trojans, and KBOs has an integrated flux of less than ~6x10^{-6} cm^{-2} s^{-1} (100-500 MeV), which corresponds to ~12 times the Lunar albedo, and may be detectable by the forthcoming Gamma Ray Large Area Space Telescope (GLAST). If detected by GLAST, it can provide unique direct information about the number of small bodies in each system that is difficult to assess by any other method. Additionally, the KBO albedo flux can be used to probe the spectrum of CR nuclei at close-to-interstellar conditions. The orbits of MBAs, Trojans, and KBOs are distributed near the ecliptic, which passes through the Galactic center and high Galactic latitudes. Therefore, the asteroid gamma-ray albedo has to be taken into account when analyzing weak gamma-ray sources close to the ecliptic, especially near the Galactic center and for signals at high Galactic latitudes, such as the extragalactic gamma-ray emission. The asteroid albedo spectrum also exhibits a 511 keV line due to secondary positrons annihilating in the rock. This may be an important and previously unrecognized celestial foreground for the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the Galactic 511 keV line emission including the direction of the Galactic center.Comment: 10 pages, 5 figures, 1 table, emulateapj.cls; ApJ in press. Calculations extended to include Jovian and Neptunian Trojan groups, and Centaurs, in addition to Main Belt Asteroids and Kuiper Belt Objects. Many other considerable change

    Structure Through Colour: A Pixel Approach Towards Understanding Galaxies

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    We present a study of pixel Colour Magnitude Diagrams (pCMDs) for a sample of 69 nearby galaxies chosen to span a wide range of Hubble types. Our goal is to determine how useful a pixel approach is for studying galaxies according to their stellar light distributions and content. The galaxy images were analysed on a pixel-by-pixel basis to reveal the structure of the individual pCMDs. We find that the average surface brightness (or projected mass density) in each pixel varies according to galaxy type. Early-type galaxies exihibit a clear ``prime sequence'' and some pCMDs of face-on spirals reveal ``inverse-L'' structures. We find that the colour dispersion at a given magnitude is found to be approximately constant in early-type galaxies but this quantity varies in the mid and late-types. We investigate individual galaxies and find that the pCMDs can be used to pick out morphological features. We discuss the discovery of ``Red Hooks'' in the pCMDs of six early-type galaxies and two spirals and postulate their origins. We develop quantitative methods to characterise the pCMDs, including measures of the blue-to-red light ratio and colour distributions of each galaxy and we organise these by morphological type. We compare the colours of the pixels in each galaxy with the stellar population models of Bruzual & Charlot (2003) to calculate star formation histories for each galaxy type and compare these to the stellar mass within each pixel. Maps of pixel stellar mass and mass-to-light ratio are compared to galaxy images. We apply the pCMD technique to three galaxies in the Hubble Ultra Deep Field to test the usefulness of the analysis at high redshift. We propose that these results can be used as part of a new system of automated classification of galaxies that can be applied at high redshift.Comment: 16 pages, 20 figures, MNRAS, accepted. For high resolution figures see: http://www.nottingham.ac.uk/~ppxmml/lcm_2007.pd
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