256 research outputs found
Single-filament Composite MgB2/SUS Ribbons by Powder-In-Tube Process
We report the successful fabrication of single-filament composite MgB2/SUS
ribbons, as an ultra-robust conductor type, employing the powder-in-tube (PIT)
process, by swaging and cold rolling only. The remarkable transport critical
current (Ic) of the non-sintered MgB2/SUS ribbon has observed, as an unexpected
result. Transport critical currents Ic ~ 316 A at T = 4.2 K and Ic ~ 82 A at T
= 20 K were observed at self-field, for the non-sintered composite MgB2/SUS
ribbon. In addition, the persistent current density Jp values, that were
estimated by Bean formula, were more than ~ 7  105 A/cm2 at T = 5 K,
and ~ 1.2  105 A/cm2 at T = 30 K, for the sintered composite MgB2/SUS
ribbon, at H = 0 G.Comment: 10 pages, 4 figure
Conformation of a Polyelectrolyte Complexed to a Like-Charged Colloid
We report results from a molecular dynamics (MD) simulation on the
conformations of a long flexible polyelectrolyte complexed to a charged sphere,
\textit{both negatively charged}, in the presence of neutralizing counterions
in the strong Coulomb coupling regime. The structure of this complex is very
sensitive to the charge density of the polyelectrolyte. For a fully charged
polyelectrolyte the polymer forms a dense two-dimensional "disk", whereas for a
partially charged polyelectrolyte the monomers are spread over the colloidal
surface. A mechanism involving the \textit{overcharging} of the polyelectrolyte
by counterions is proposed to explain the observed conformations.Comment: 4 pages, 4 figures (6 EPS files
A "critical" climatic evaluation of last interglacial (MIS 5e) records from the Norwegian Sea
Sediment cores from the Norwegian Sea were studied to evaluate interglacial climate conditions of the marine isotope stage 5e (MIS 5e). Using planktic forminiferal assemblages as the core method, a detailed picture of the evolution of surface water conditions was derived. According to our age model, a step-like deglaciation of the Saalian ice sheets is noted between ca. 135 and 124.5 Kya, but the deglaciation shows little response with regard to surface ocean warming. From then on, the rapidly increasing abundance of subpolar forminifers, concomitant with decreasing iceberg indicators, provides evidence for the development of interglacial conditions sensu stricto (5e-ss), a period that lasted for about 9 Ky. As interpreted from the foraminiferal records, and supported by the other proxies, this interval of 5e-ss was in two parts: showing an early warm phase, but with a fresher, i.e., lower salinity, water mass, and a subsequent cooling phase that lasted until ca. 118.5 Kya. After this time, the climatic optimum with the most intense advection of Atlantic surface water masses occurred until ca. 116 Kya. A rapid transition with two notable climatic perturbations is observed subsequently during the glacial inception. Overall, the peak warmth of the last interglacial period occurred relatively late after deglaciation, and at no time did it reach the high warmth level of the early Holocene. This finding must be considered when using the last interglacial situation as an analogue model for enhanced meridional transfer of ocean heat to the Arctic, with the prospect of a future warmer climate
School-based prevention for adolescent Internet addiction: prevention is the key. A systematic literature review
Adolescents’ media use represents a normative need for information, communication, recreation and functionality, yet problematic Internet use has increased. Given the arguably alarming prevalence rates worldwide and the increasingly problematic use of gaming and social media, the need for an integration of prevention efforts appears to be timely. The aim of this systematic literature review is (i) to identify school-based prevention programmes or protocols for Internet Addiction targeting adolescents within the school context and to examine the programmes’ effectiveness, and (ii) to highlight strengths, limitations, and best practices to inform the design of new initiatives, by capitalizing on these studies’ recommendations. The findings of the reviewed studies to date presented mixed outcomes and are in need of further empirical evidence. The current review identified the following needs to be addressed in future designs to: (i) define the clinical status of Internet Addiction more precisely, (ii) use more current psychometrically robust assessment tools for the measurement of effectiveness (based on the most recent empirical developments), (iii) reconsider the main outcome of Internet time reduction as it appears to be problematic, (iv) build methodologically sound evidence-based prevention programmes, (v) focus on skill enhancement and the use of protective and harm-reducing factors, and (vi) include IA as one of the risk behaviours in multi-risk behaviour interventions. These appear to be crucial factors in addressing future research designs and the formulation of new prevention initiatives. Validated findings could then inform promising strategies for IA and gaming prevention in public policy and education
A discrete host-parasitoid model with development of pesticide resistance and IPM strategies
The development of pesticide resistance significantly affects the outcomes of pest control. A quantitative depiction of the effects of pesticide resistance development on integrated pest management (IPM) strategies and pest control outcomes is challenging. To address this problem, a discrete host-parasitoid model with pesticide resistance development and IPM strategies is proposed and analyzed. The threshold condition of pest eradication which reveals the relationship between the development of pest resistance and the rate of natural enemy releases is provided and analyzed, and the optimal rate for releasing natural enemies was obtained based on this threshold condition. Furthermore, in order to reduce adverse effects of the pesticide on natural enemies, the model has been extended to consider the spraying of pesticide and releases of natural enemies at different times. The effects of the dynamic complexity and different resistance development equations on the main results are also discussed
Longitudinal analysis of alcohol use and intimate partner violence perpetration among men with HIV in northern Vietnam
Background: Alcohol use is a known risk factor for male-perpetrated intimate partner violence (IPV), although few studies have been conducted globally and among men with HIV (MWH). We estimated the longitudinal effects of alcohol use on IPV perpetration among MWH. Methods: This study is a secondary analysis of randomized controlled trial data among male and female antiretroviral treatment patients with hazardous alcohol use in Thai Nguyen, Vietnam. Analyses were restricted to male participants who were married/cohabitating (N = 313). Alcohol use was assessed as proportion days alcohol abstinent, heavy drinking, and alcohol use disorder (AUD) using the Timeline Followback and Mini International Neuropsychiatric Interview questionnaire. Multilevel modeling was used to estimate the effects of higher versus lower average alcohol use on IPV perpetration (between-person effects) and the effects of time-specific deviations in alcohol use on IPV perpetration (within-person effects). Results: Participants with higher average proportion days alcohol abstinent had decreased odds of IPV perpetration (adjusted Odds Ratio [aOR] = 0.43, p = 0.03) and those with higher average heavy drinking and AUD had increased odds of IPV perpetration (Heavy drinking: aOR = 1.05, p = 0.002; AUD: aOR = 4.74, p < 0.0001). Time-specific increases in proportion days alcohol abstinent were associated with decreased odds of IPV perpetration (aOR = 0.39, p = 0.02) and time-specific increases in AUD were associated with increased odds of IPV perpetration (aOR = 2.95, p = 0.001). Within-person effects for heavy drinking were non-significant. Conclusions: Alcohol use is associated with IPV perpetration among Vietnamese men with HIV. In this context, AUD and frequent drinking are stronger correlates of IPV perpetration as compared to heavy drinking
Development and Validation of an Inflammatory Bowel Diseases Monitoring Index for Use With Mobile Health Technologies
Cellular mechanisms in basic and clinical gastroenterology and hepatolog
A Nationwide 2010-2012 Analysis of U.S. Health Care Utilization in Inflammatory Bowel Diseases
Cellular mechanisms in basic and clinical gastroenterology and hepatolog
Spectroscopic quantification of soil phosphorus forms by 31p-nmr after nine years of organic or mineral fertilization
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