647 research outputs found
Somalia: Paradoxes of Private Prosperity, Poverty Pockets, Volatile Vulnerability and Public Pauperisation
Second draft of report for UNICEF
An Improved Flexibility Formulation for Nonlinear Analysis of Reinforced Concrete Frames
In this paper the finite element flexibility-based formulation for a reinforced concrete frame element is discussed. The formulation takes account of material non-linearity on the basis of the onedimensional stress-strain relationships akin to the traditional fibre element. However, the fibres in this method are replaced by transverse integration points to improve the efficiency of the method. The compatibility of strain in each section is satisfied by adopting the Navier-Bernoulli hypothesis and effect of shear tractions on the nonlinear response of the material is neglected. Two different iterative solution strategies based on secant and tangent stiffness, consistent with the flexibility formulation are employed for solving the governing equation. The accuracy of assumptions and performance of the solution schemes are studied by a numerical example
Consistent Mass and Exact Displacement Shape Function for a Tapered Curved Frame Element
The principle of virtual force is employed to derive the exact shape function for a taperedcurved frame element in space and these shape functions ca n be employed to calculate the exact consistent mass and geometric stiffness matrixes for curved-tapered frame elements. The lack of any displacement shape function with exact fulfilment of equilibrium equations by an accurate force interpolation is the salient feature of this approach. The formulation adopts the linear elastic behaviour of the material and the strain compatibility is satisfied based on the Nevier-Bernoulli hypothesis. Shear deformations are considered and the Saint-Venat hypothesis for torsion is adopted. The efficiency and accuracy of the formulation are verified using some numerical examples
Disruptive behavior scale for adolescents (DISBA): development and psychometric properties
Background: Growing evidence indicates that if disruptive behavior is left unidentified and untreated, a significant proportion of these problems will persist and may develop into problems linked with delinquency, substance abuse, and violence. Research is needed to develop valid and reliable measures of disruptive behavior to assist recognition and impact of treatments on disruptive behavior. The aim of this study was to develop and evaluate the psychometric properties of a scale for disruptive behavior in adolescents.
Methods: Six hundred high school students (50% girls), ages ranged 15–18 years old, selected through multi stage random sampling. Psychometrics of the disruptive behavior scale for adolescents (DISBA) (Persian version) was assessed through content validity, explanatory factor analysis (EFA) using Varimax rotation and confirmatory factor analysis (CFA). The reliability of this scale was assessed via internal consistency and test–retest reliability.
Results: EFA revealed four factors accounting for 59% of observed variance. The final 29-item scale contained four factors: (1) aggressive school behavior, (2) classroom defiant behavior, (3) unimportance of school, and (4) defiance to school authorities. Furthermore, CFA produced a sufficient Goodness of Fit Index \u3e 0.90. Test–retest and internal consistency reliabilities were acceptable at 0.85 and 0.89, respectively.
Conclusions: The findings from this study suggest that the Iranian version of DISBA questionnaire has content validity. Further studies are needed to evaluate stronger psychometric properties for DISBA
Generalized Sagnac Effect
Experiments were conducted to study light propagation in a light waveguide
loop consisting of linearly and circularly moving segments. We found that any
segment of the loop contributes to the total phase difference between two
counterpropagating light beams in the loop. The contribution is proportional to
a product of the moving velocity v and the projection of the segment length
Deltal on the moving direction, Deltaphi=4pivDeltal/clambda. It is independent
of the type of motion and the refractive index of waveguides. The finding
includes the Sagnac effect of rotation as a special case and suggests a new
fiber optic sensor for measuring linear motion with nanoscale sensitivity.Comment: 3 pages (including 3 figures
The survival rate of hepatocellular carcinoma in asian countries: A systematic review and meta-analysis
Hepatocellular carcinoma or Liver cancer (LC) is the sixth most common cancer and the fourth cause of death worldwide in 2018. There has not been a comprehensive study on the survival rate of patients with LC in Asia yet. Therefore, the present study was conducted to evaluate the survival rate of patients with LC in Asian countries. The methodology of the present study is based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) statement. The researchers searched five international databases including Medline/PubMed, Scopus, Embase, Web of Knowledge and ProQuest until July 1, 2018. We also searched Google Scholar for detecting grey literature. The Newcastle-Ottawa Quality Assessment Form was used to evaluate the quality of selected papers. A total of 1425 titles were retrieved. 63 studies met the inclusion criteria. Based on the random-effect model one-year, three-year and five-year survival rate of LC were 34.8 (95 CI; 30.3-39.3), 19 (95 CI; 18.2-21.8) and 18.1 (95 CI;16.1-20.1) respectively. According to the results of our study, the LC survival rate in Asian countries is relatively lower than in Europe and North America. © 2020, Leibniz Research Centre for Working Environment and Human Factors. All rights reserved
Truncated Hexa-Octahedral Magnetite Crystals in Martian Meteorite ALH84001: Evidence of Biogenic Activity on Early Mars
The landmark paper by McKay et al. [1] cited four lines of evidence associated with the Martian meteorite ALH84001 to support the hypothesis that life existed on Mars approximately 4 Ga ago. Now, more than five years later, attention has focused on the ALH84001 magnetite grains embedded within carbonate globules in the ALH84001 meteorite. We have suggested that up to approx.25% of the ALH84001 magnetite crystals are products of biological activity [e.g., 2]. The remaining magnetites lack sufficient characteristics to constrain their origin. The papers of Thomas Keprta et al. were criticized arguing that the three dimensional structure of ALH84001 magnetite crystals can only be unambiguously determined using electron tomographic techniques. Clemett et al. [3] confirmed that magnetites produced by magnetotactic bacteria strain MV-I display a truncated hexa-octahedral geometry using electron tomography and validated the use of the multi-tilt classical transmission microscopy technique used by [2]. Recently the geometry of the purported martian biogenic magnetites was shown be identical to that for MV-1 magnetites using electron tomography [6]
A survey on the radiation protection status among radiology staff
Introduction: Radiation exposure during radiological examination is a health concern, of which radiology professionals should be cognizant. We sought to evaluate the radiation protection knowledge, attitudes, and practice (KAP) amongst radiology staff of hospitals across 10 provinces of Iran. Materials and Methods: For evaluating the level of radiation protection KAP, 553 radiology staff were enrolled. A 32-item questionnaire was designed to assess radiation protection KAP, the validity which was confirmed by members of the Medical Physics and Biostatistics departments. The questionnaire evaluated the respondents' knowledge, practice, and attitudes towards the basic principles of radiation protection, the necessity of using protective equipment, and their performance in the implementation of radiation protection recommendations. Results: We found no significant difference in the level of radiation protection KAP between male and female radiology staff and among those with different educational levels and ages (P > 0.05). However, there was a significant association between radiation protection KAP and working experience, hospital size, and hospital type (P 0.05). Conclusion: Our results showed that the level of radiation protection KAP among radiology staff is inadequate. This might be due to the lack of ongoing training courses concerning protection against ionizing radiation. Thus, sustained training of radiation protection principles can promote KAP among the staff of radiology departments, and in turn, reduce public dose from medical diagnostic modalities. © 2018, Mashhad University of Medical Sciences
The relevance of nanoscale biological fragments for ice nucleation in clouds
Most studies of the role of biological entities as atmospheric ice-nucleating particles have focused on relatively rare supermicron particles such as bacterial cells, fungal spores and pollen grains. However, it is not clear that there are sufficient numbers of these particles in the atmosphere to strongly influence clouds. Here we show that the ice-nucleating activity of a fungus from the ubiquitous genus Fusarium is related to the presence of nanometre-scale particles which are far more numerous, and therefore potentially far more important for cloud glaciation than whole intact spores or hyphae. In addition, we quantify the ice-nucleating activity of nano-ice nucleating particles (nano-INPs) washed off pollen and also show that nano-INPs are present in a soil sample. Based on these results, we suggest that there is a reservoir of biological nano-INPs present in the environment which may, for example, become aerosolised in association with fertile soil dust particles
Contractile profile of esophageal and gastric fundus strips in experimental doxorubicin-induced esophageal atresia
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