2,128 research outputs found
Social Media Use and Childrenâs Wellbeing
Childhood circumstances and behaviours have been shown to have important persistent effects in later life. One aspect of childhood that has changed dramatically in the past decade, and is causing concern among policy makers and other bodies responsible for safeguarding children, is the advent of social media, or online social networking. This research explores the effect of childrenâs digital social networking on their subjective wellbeing. We use a large representative sample of 10-15 year olds over the period 2010 to 2014 from the UK Household Longitudinal Study, and estimate the effect of time spent chatting on social websites on a number of outcomes which reflect how these children feel about different aspects of their life, specifically: school work; appearance; family; friends; school attended; and life as a whole. We deal with the potential endogeneity of social networking via an instrumental variables approach using information on broadband speeds and mobile phone signal strength published by Ofcom. Our results suggest that spending more time on social networks reduces the satisfaction that children feel with all aspects of their lives, except for their friendships; and that girls suffer more adverse effects than boys. As well as addressing policy makersâ concerns about the effects of digital technology on children, this work also contributes to wider debates about the socioeconomic consequences of the internet and digital technologies more generally, a debate which to date has largely been based on evidence from outside of the UK
Isotope sourcing of prehistoric willow and tule textiles recovered from western Great Basin rock shelters and caves e proof of concept
Isotope and trace-metal analyses were used to determine the origin of plants used to manufacture prehistoric textiles (basketry and matting) from archaeological sites in the western Great Basin. Research focused on strontium (87Sr/86Sr) and oxygen (18O/16O) isotope ratios of willow (Salix sp.) and tule (Schoenoplectus sp.), the dominant raw materials in Great Basin textiles. The oxygen-isotope data indicated that the willow and tule used to produce the textiles were harvested from the banks of rivers or in marshes characterized by flowing water and not from lakes or sinks. The strontium-isotope data were useful in showing which plants came from the Humboldt River and which came from rivers headed in the Sierra Nevada
A Comparison of the Tensile and Bending Properties of Dental Gold Wires
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68282/2/10.1177_00220345510300022001.pd
Bronchodilator tolerance and rebound bronchoconstriction during regular inhaled ÎČ -agonist treatment
AbstractThere is uncertainty about the development of airway tolerance to ÎČ -agonists and the phenomenon of rebound bronchoconstriction on ÎČ -agonist withdrawal. We have recently completed a study of the regular terbutaline and budesonide treatment in asthma. We report our observations on the effect of starting and stopping terbutaline treatment on morning and evening peak flows.The study was a randomized four-way, double-dummy, cross-over comparison of regular inhaled terbutaline (500â1000 ÎŒ g four times daily), budesonide, combined treatment and matching placebo. Each treatment was given for 6 weeks following a 4 week single-blind placebo washout. Ipratropium was used for symptom relief. No other asthma medication was permitted during either the treatment or wash-out periods. Evaluable data were obtained from 52 subjects for both placebo and terbutaline treatment. Changes in mean morning and evening peak flows during terbutaline treatment were compared to the baseline peak flows during the last 2 weeks of the preceding washout. The peak flow changes on stopping terbutaline were also analysed.Mean morning peak flow was not significantly different during terbutaline treatment when compared to either baseline or placebo treatment. Evening peak flows were significantly higher during terbutaline treatment [mean increase 23·1l minâ1(95%CI=18·8, 27·4)]. Analysis of the peak flow changes on a day-by-day basis revealed an initial increase in morning peak flows for the first 2 days of treatment of 19·2 and 13·4l minâ1[increases of 25·0 and 17·3l minâ1in comparison with the corresponding values during placebo (P<0·01)] followed by a return to baseline. The increase in evening peak flows was also greater for the first 2 days of treatment than for the remainder of the treatment period (P<0·01). On ceasing terbutaline treatment there was a fall in mean morning peak flow below the baseline on the following morning of 21·6l minâ1(P<0·05 compared to placebo).The temporary increase in morning peak flows and greater than expected rise in evening peak flows for the first 2 days of treatment suggest the development of tolerance to the bronchodilator effect of terbutaline. Similarly, the fall in morning peak flows on treatment withdrawal suggests rebound bronchoconstriction. These effects are likely to be mediated by downregulation of the ÎČ -receptor during treatment. The clinical significance of these changes is uncertain in view of the stability of overall asthma control during terbutaline treatment, but sudden withdrawal of ÎČ -agonist treatment could conceivably lead to a deterioration in asthma control
Interface state contribution to the photovoltaic effect in organic phototransistors:Photocapacitance measurements and optical sensing
Made available in DSpace on 2018-12-11T16:50:21Z (GMT). No. of bitstreams: 0
Previous issue date: 2018-01-01Coordenação de Aperfeiçoamento de Pessoal de NĂvel Superior (CAPES)Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)Instituto Nacional de CiĂȘncia e Tecnologia em EletrĂŽnica OrgĂąnicaWe report the results of an investigation into the contribution that trapping in interface states makes to the photovoltaic effect observed in organic phototransistors. To isolate this effect from other processes that occur in the transistor structure when under illumination, we focus attention on the photo-response of metal-insulator-semiconductor (MIS) capacitors - the core structure of transistors. The capacitors comprised poly(3-hexylthiophene), (P3HT), as the active semiconductor in combination with one of three insulators, namely, poly(amide-imide), (PAI), SU-8 photoresist and polysilsesquioxane (PSQ). Following initial characterization in the dark, the capacitor response was measured both during and after irradiation with light in the wavelength range 400â700 nm. Three different approaches were employed to study the photo-response, each providing a different insight into the processes occurring. Capacitance-voltage sweeps before, during and after illumination provided direct evidence supporting the view that the photovoltaic effect occurred as a result of electron trapping in interface states of density up to âŒ2 Ă 1012 cmâ2 in the P3HT/PAI combination but lower for SU-8 and PSQ. The dynamic photo-response, in which device capacitance was held constant by changing the applied bias, showed a fast component related to optically induced photoconduction in the semiconductor and a slower component reflecting the dynamics of interface electron trapping. Finally, photo-induced capacitance changes occurring with constant applied voltage were used to demonstrate a simple 3 Ă 3 imaging array.School of Electronic Engineering Bangor University, Dean StreetBrazilian Nanotechnology National Laboratory (LNNano) Brazilian Centre of Research in Energy and Materials (CNPEM)Department of Physics SĂŁo Paulo State University (UNESP), PO Box 266Institute of Physics of SĂŁo Carlos University of SĂŁo Paulo (USP), PO Box 369Catarinense Federal Institute of Education Science and Technology, PO Box 21Department of Physics SĂŁo Paulo State University (UNESP), PO Box 26
Role of carbon dioxide and ion transport in the formation of sub-embryonic fluid by the blastoderm of the Japanese quail
1. The explanted blastoderm of the Japanese quail was used to explore the role of ions and carbon dioxide in determining the rate of sub-embryonic fluid (SEF) production between 54 and 72 h of incubation.
2. Amiloride, an inhibitor of Na+/H+ exchange, at concentrations of 10-3 to 10-6 M substantially decreased the rate of SEF production when added to the albumen culture medium. N-ethylmaleimide, an inhibitor of V type H+ ATPase, also decreased this rate but only to a small extent at the highest dose applied, 10-3 M. Both inhibitors had no effect on SEF production when added to the SEF. 3. The inhibitors of cellular bicarbonate and chloride exchange, 4-acetamido-4-'isothiocyano-2, 2-'disulphonic acid (SITS) and 4,4'diisothiocyanostilbene-2,2-'disulphonic acid (DIDS), had no effect upon SEF production.
4. Ouabain, an inhibitor of Na+/K+ ATPase, decreased SEF production substantially at all concentrations added to the SEF (10-3 to 10-6 M). Three sulphonamide inhibitors of carbonic anhydrase, acetazolamide, ethoxzolamide and benzolamide, decreased SEF production when added to the SEF at concentrations of 10-3 to 10-6 M. Benzolamide was by far the most potent. Neither ouabain nor the sulphonamides altered SEF production when added to the albumen culture medium.
5. Using a cobalt precipitation method, carbonic anhydrase activity was localised to the endodermal cells of the area vasculosa. The carbonic anhydrase activity was primarily associated with the lateral plasma membranes, which together with the potent inhibitory effect of benzolamide, suggests the carbonic anhydrase of these cells is the membrane-associated form, CA IV.
6. The changes in SEF composition produced by inhibitors were consistent with the production of SEF by local osmotic gradients.
7. It is concluded that a Na+/K+ ATPase is located on the basolateral membranes of the endodermal cells of the area vasculosa , and that a sodium ion/hydrogen ion exchanger is located on their apical surfaces. Protons for this exchanger would be provided by the hydration of CO2 catalysed by the membrane-associated carbonic anhydrase. Furthermore, it is proposed that the prime function of the endodermal cells of the area vasculosa is the production of SEF
Displaced but not replaced: the impact of e-learning on academic identities in higher education.
Challenges facing universities are leading many to implement institutional strategies to incorporate e-learning rather than leaving its adoption up to enthusiastic individuals. Although there is growing understanding about the impact of e-learning on the student experience, there is less understanding of academicsâ perceptions of e-learning and its impact on their identities. This paper explores the changing nature of academic identities revealed through case study research into the implementation of e-learning at one UK university. By providing insight into the lived experiences of academics in a university in which technology is not only transforming access to knowledge but also influencing the balance of power between academic and student in knowledge production and use, it is suggested that academics may experience a jolt to their âtrajectory of selfâ when engaging with e-learning. The potential for e-learning to prompt loss of teacher presence and displacement as knowledge expert may appear to undermine the ontological security of their academic identity
The Prenatal Environment in Twin Studies: A Review on Chorionicity
A literature search was conducted to identify articles examining the association of chorionicity (e.g., whether twins share a single chorion and thus placenta or have separate chorions/placentas) and genetics, psychiatry/behavior, and neurological manifestations in humans twins and higher-order multiples. The main aim was to assess how frequently chorionicity has been examined in relation to heritability estimates, and to assess which phenotypes may be most sensitive to, or affected by, bias in heritability estimates because of chorionicity. Consistent with the theory that some chorionicity effects could lead to overestimation and others to underestimation of heritability, there were instances of each across the many phenotypes reviewed. However, firm conclusions should not be drawn since some of the outcomes were only examined in one or few studies and often sample sizes were small. While the evidence for bias due to chorionicity was mixed or null for many outcomes, results do, however, consistently suggest that heritability estimates are underestimated for measures of birth weight and early growth when chorionicity is not taken into account
The K^*_0(800) scalar resonance from Roy-Steiner representations of pi K scattering
We discuss the existence of the light scalar meson K^*_0(800) (also called
kappa) in a rigorous way, by showing the presence of a pole in the pi K --> pi
K amplitude on the second Riemann sheet. For this purpose, we study the domain
of validity of two classes of Roy-Steiner representations in the complex energy
plane. We prove that one of them is valid in a region sufficiently broad in the
imaginary direction. From this representation, we compute the l=0 partial wave
in the complex plane with neither additional approximation nor model
dependence, relying only on experimental data. A scalar resonance with
strangeness S=1 is found with the following mass and width: E_kappa = 658 \pm
13 MeV and Gamma_kappa = 557 \pm 24 MeV.Comment: 16 pages, 8 figures. Domain of validity of a Roy-Steiner
representation corrected and enlarged, and features of the K^*_0(800) pole
discussed in more details. Conclusions unchange
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