450 research outputs found
Resultados de un programa para reducir el miedo y aumentar la autoeficacia para hablar en público en estudiantes universitarios de primer año
Se expone el resultado de un programa para
reducir el temor a hablar en público e incrementar la
autoeficacia entre estudiantes de Magisterio. La muestra
está compuesta por 158 personas del grupo experimental
y 101 del grupo control. Los resultados evaluados
a través del Cuestionario de Autoeficacia para
Hablar en Público muestran que los participantes en el
programa mejoran su autoeficacia, sobre todo aquellos
con puntuaciones más bajas, y que estos resultados
se mantienen a lo largo del tiempo. Se concluye que la
intervención ha sido eficaz y ha dotado a los alumnos
de más recursos para aprovecharse de los factores que
el contexto académico ofrece para desarrollar la competencia
para hablar en público
Bonding strength of stainless steel rebars in concretes exposed to marine environments
Many studies have corroborated the use of Stainless Steel Reinforcements (SSR) for structures in corrosive environments. However, even though the conditions for their employment are specified in different standards, their use is always tied to the same requirements for standard carbon steel rebars (B500SD), among which an equivalent carbon content for weldability that is inappropriate for SSR. Further studies are therefore needed to develop suitable standards that will focus on addressing not only the content, but also the technical advantages of SSR for structural engineering under specific conditions. The results of this study show improvements in the maximum bond strength behaviour of different SSRs in simulated marine environments, in comparison with B500SD, in terms of several variables: Bond index, curing time, w/c ratio, and corrosion. Specifically, the test results showed that: (a) the Bond index was not a suitable parameter for the evaluation of the bonding strength of SSR; (b) the curing time increased the bonding strength of Lean Duplex Stainless Steel (LDSS); (c) a higher w/c ratio tended to decrease bond strength, although less so in LDSS; and, (d) corrosion reduced bond strength, especially in B500SD.The tests presented in this manuscript were performed as part of the IISIS: ‘‘Investigación Integrada en Islas Sostenibles” (Integrated research in Sustainable Islands) research project, in receipt of funding from the Centre for the Development of Industrial Technology (CDTI) and the Technological Fund, part of the Spanish Ministry of Industry, through the INNPRONTA research programme.
The authors would also like to thank Research Group IT781-13 ‘‘Comprehensive sustainability in building systems and materials”, at the University of the Basque Country, for scientific assistance and support. Finally, we are also especially thankful to ACERINOX EUROPA (part of the ACERINOX Group) for funding the IISIS project, supplying the necessary rebar samples for testing, and particularly to Rafael Sanchez and Julia Contreras from Technical Dpt./Labs for providing their expertise and for their commitment that have greatly assisted our researc
A plain linear rule for fatigue analysis under natural loading considering the coupled fatigue and corrosion effect
Fatigue under variable amplitude loading is currently assessed by applying the Palmgren-Miner linear rule in structural standards. However, this linear rule is inadequate in natural scenarios with coupled fatigue and corrosion effects, because the coupled corrosion-fatigue process synergistically accelerates deterioration. In view of the absence of specifications for the coupled fatigue-corrosion effect in structural standards, the objective here is to develop a simple and practical correction factor that will ensure a conservative linear summation of damage, taking the corrosion-fatigue effect into account. The theoretical consistency and the feasibility of the new adapted rule are tested in a case study
NR1H4 (nuclear receptor subfamily 1, group H, member 4)
Review on NR1H4, with data on DNA/RNA, on the protein encoded and where the gene is implicated
Recommended from our members
Heparin versus 0.9% sodium chloride locking for prevention of occlusion in central venous catheters in adults
Background
Intermittent locking of central venous catheters (CVCs) is undertaken to help maintain their patency. There are systematic variations in care: some practitioners use heparin (at different concentrations), whilst others use 0.9% NaCl (normal saline). This review looks at the effectiveness and safety of intermittent locking with heparin compared to 0.9% NaCl to see if the evidence establishes whether one is better than the other. This work is an update of a review first published in 2014.
Objectives
To assess the effectiveness and safety of intermittent locking of CVCs with heparin versus normal saline (NS) in adults to prevent occlusion.
Search methods
The Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (last searched 11 June 2018) and the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 5). Searches were also carried out in MEDLINE, Embase, CINAHL, and clinical trials databases (11 June 2018).
Selection criteria
We included randomised controlled trials in adults ≥ 18 years of age with a CVC that compared intermittent locking with heparin at any concentration versus NS. We applied no restriction on language.
Data collection and analysis
Two review authors independently selected trials, assessed quality, and extracted data. We contacted trial authors to retrieve additional information, when necessary.We carried out statistical analysis using ReviewManager 5 and assessed the overall quality of the evidence supporting assessed outcomes using GRADE. We carried out prespecified subgroup analysis.
Main results
We identified five new studies for this update (six prior studies were included in the original review), bringing the number of eligible studies to 11, with a total of 2392 participants. We noted differences in methods used by the included studies and variation in heparin concentrations (10 to 5000 IU/mL), time to follow-up (1 to 251.8 days), and the unit of analysis used (participant, catheter, line access). Combined results fromthese studies showed fewer occlusions with heparin than with NS (risk ratio (RR) 0.70, 95%confidence interval (CI) 0.51 to 0.95; P = 0.02; 1672 participants; 1025 catheters from 10 studies; I² = 14%) and provided very low-quality evidence. We carried out subgroup analysis by unit of analysis (testing for subgroup differences (P = 0.23; I² = 30.3%). When the unit of analysis was the participant, results show no clear differences in all occlusions between heparin and NS (RR 0.79, 95% CI 0.58 to 1.08; P = 0.15; 1672 participants; seven studies). Subgroup analysis using the catheter as the unit of analysis shows fewer occlusions with heparin use (RR 0.53, 95% CI 0.29 to 0.95; P = 0.03; 1025 catheters; three studies). When the unit of analysis was line access, results show no clear differences in occlusions between heparin and NS (RR 1.08, 95% CI 0.84 to 1.40; 770 line accesses; one study). We found no clear differences in the duration of catheter patency (mean difference (MD) 0.44 days, 95% CI -0.10 to 0.99; P = 0.11; 1036 participants; 752 catheters; six studies; low-quality evidence). We found no clear evidence of a difference in the following: CVC-related sepsis (RR 0.74, 95% CI 0.03 to 19.54; P = 0.86; 1097 participants; two studies; low-quality evidence); mortality (RR 0.76, 95% CI 0.44 to 1.31; P = 0.33; 1100 participants; three studies; low-quality evidence); haemorrhage at any site (RR 1.32, 95% CI 0.57 to 3.07; P = 0.52; 1245 participants; four studies; moderatequality evidence); or heparin-induced thrombocytopaenia (RR 0.21, 95% CI 0.01 to 4.27; P = 0.31; 443 participants; three studies; low-quality evidence). Themain reasons for downgrading the quality of evidencewere unclear allocation concealment, imprecision, and suspicion of publication bias.
Authors’ conclusions
Given the very low quality of the evidence, we are uncertain whether intermittent locking with heparin results in fewer occlusions than intermittent locking with NS. Low-quality evidence suggests that heparin may have little or no effect on catheter patency. Although we found no evidence of differences in safety (sepsis, mortality, or haemorrhage), the combined trials are not powered to detect rare adverse events such as heparin-induced thrombocytopaenia
Risk Assessment Methodologies to Safeguard Historic Urban Areas from the Effects of Climate Change
A systematic and critical review of the existing literature on climate-change riskassessment methodologies for historic urban areas is presented, in view of the increasing likelihood of extreme weather events. Key performance indicators are identified for use in future risk assessment methodologies that address both the elements of historic urban areas as a system and the potential impact of prolonged heat waves. To do so, a systematic search of the existing literature on Web of Science and Scopus was conducted, with the aim of identifying and characterizing existing methodologies on vulnerability and risk assessment for cultural heritage exposed to the effects of a changing climate. The main characteristics of the methodologies that need to be addressed in the near future and key knowledge gaps were identified, among them, the lack of holistic heat-wave risk-assessment methodologies for historic urban areas
Shapes of the Pb ground states from beta decay studies using the total absorption technique
The beta decay of Pb has been studied using the total absorption
technique at the ISOLDE(CERN) facility. The beta-decay strength deduced from
the measurements, combined with QRPA theoretical calculations, allow us to
infer that the ground states of the Pb isotopes are spherical.
These results represent the first application of the shape determination method
using the total absorption technique for heavy nuclei and in a region where
there is considerable interest in nuclear shapes and shape effects
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