52 research outputs found

    Spatial changes of beach profiles for a small tidal inlet (Currumbin Creek, Australia)

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    Many tidal inlets are actively monitored to investigate the change in flood or ebb shoals, as these sand deposits can have a major influence on the sediment budget of the adjacent coast. However, here it is hypothesized that the shores of the back barrier area can also act as a source of sediment to be considered in the sediment budget. Therefore, profile changes around Currumbin Creek tidal inlet were considered to identify the extent of such a contribution on the surrounding beach and the overall evolution of the inlet system. The results of 16 weeks survey showed that in general, the shores of the back barrier lagoon had a very marginal effect in the provision of material to the sand budget, although the gorge area is highly vulnerable and dynamic. Even an intense storm event and heavy rainfall during the data collection period, resulting in erosion of the surrounding beaches, showed no significant influence on the shore face of the lagoon

    The correlation of microstructure and mechanical properties of in-situ Al-Mg2Si cast composite processed by equal channel angular pressing

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    In this paper, the effect of equal channel angular pressing (ECAP) on microstructure and mechanical properties of hypereutectic Al-20%Mg2Si and Al-15%Mg2Si, as well as hypoeutectic Al-10%Mg2Si composites has been investigated. After fabricating the composites by in-situ casting, the composites were processed using the ECAP process up to two passes at room temperature. Microstructural studies have been carried out using a field emission scanning electron microscopy equipped with an energy dispersive X-ray spectrometer. Mechanical properties were also documented using Vickers microhardness and shear punch tests. In the hypereutectic composites, a decrease in the average size of pro-eutectic Mg2Si (Mg2Sip) particles, breakages in eutectic networks, and lengthening of the Al (α) phase in direction of shear bands were observed after the ECAP process. For instance, the average size of Mg2Sip Particles in Al-20%Mg2Si composite reduced from 40 to 17 μm after 2 passes of ECAP. Furthermore, a uniform distribution of Mg2Sip particles was developed in the matrix. In hypoeutectic composite, the ECAP process caused a uniform distribution of eutectic Mg2Si (Mg2SiE) in the matrix that considered a favorable microstructure. Microhardness measurements and shear punch results showed an ascending trend after each pass of ECAP for all specimens. For example, microhardness and shear strength of Al-20%Mg2Si increased from 88 HV and 109 MPa to 119 HV and 249 MPa after two passes indicating 35% and 34% increments, respectively. Density and porosity calculations by Archimedes principle revealed that the density of the composites increased after two passes of ECAP due to the reduction of porosity

    Behavioral feasibility of the clinical nursing information system

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    Background: Analysis of humanitarian issues affecting the implementation time of information systems to increase the acceptance of these systems is essential. Objective: The aim of this study was to assess the behavioral feasibility of the clinical nursing information system. Methods: An applied cross-sectional study was conducted with 348 nurses in 2015. Data were collected by face to face interviews and a questionnaire containing 33 questions, which were rated on a 5-point Likert scale. Face and content validity of the questionnaire was confirmed, and its reliability was estimated 0.90 through Cronbach's alpha coefficient. Data were analyzed using chi-square tests and t-test. Results: An average score of behavioral feasibility was 67.44. The rate of supply provided for implementing the clinical nursing information system was 55.2, which was in a semi-favorable level. The necessity of system deployment in the clinical nursing sector had the highest frequency (88.2) and interference of redesigning structures with the current work had the lowest frequency (43.6). Conclusion: The possibility of implementation of the clinical nursing information system in a behavioral dimension is at a semi-favorable level. To increase the acceptance of the system, presenting a new system as a positive change and further training of the nurses is recommended. © 2019 Jeddi et al

    Echocardiographic findings and joint hypermobility: Patients with mitral valve prolapse vs. healthy controls

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    Background: Mitral valve prolapse is a relatively common valvular abnormality in most communities and joint hypermobility (JHM) is also seen in many healthy people as well as in certain clinical disorders, such as Marfan syndrome. The present study was designed to investigate the association between joint hypermobility and mitral valve prolapse (MVP) in an Iranian population sample. Methods: Fifty-seven patients with nonrheumatic and isolated mitral anterior leaflet prolapse (24 men and 33 women, mean age 23.5 +/-2.3) and 51 healthy subjects (20 men and 31 women, mean age 22.9+/-2.3) were studied. The presence of JHM was evaluated according to the Carter-Wilkinson & Beighton criteria. Echocardiographic examination was performed in all subjects and the correlation between the echocardiographic features of the mitral valve and the hypermobility score were investigated. Results: The frequency of JHM in patients with MVP was found to be significantly higher than that of controls (26.3 vs. 7.8), with mean JHM scores of 3.1+/-2.2 and 1.9+/-1.7, respectively. The patients in the MVP group had significantly increased the anterior mitral leaflet thickness (AMLT, 3.4+/-0.4 mm vs. 3.0+/-0.3 mm; p<0.0005) and maximal leaflet displacement (MLD, 2.4+/-0.3 mm vs. 1.5+/-0.2 mm; p<0.0005) compared to the controls. Conclusions: We detect a statistically significant relationship between isolated MVP and joint hypermobility as well as between the severity of JHM and echocardiographic features of the mitral leaflets. These results suggest a common etiology for MVP and JHM, which should be investigated in future well-conducted studies. © 2008, Tehran University of Medical Sciences. All rights reserved

    Loop Quantum Cosmology: A Status Report

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    The goal of this article is to provide an overview of the current state of the art in loop quantum cosmology for three sets of audiences: young researchers interested in entering this area; the quantum gravity community in general; and, cosmologists who wish to apply loop quantum cosmology to probe modifications in the standard paradigm of the early universe. An effort has been made to streamline the material so that, as described at the end of section I, each of these communities can read only the sections they are most interested in, without a loss of continuity.Comment: 138 pages, 15 figures. Invited Topical Review, To appear in Classical and Quantum Gravity. Typos corrected, clarifications and references adde

    A SARS-CoV-2 protein interaction map reveals targets for drug repurposing

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    The novel coronavirus SARS-CoV-2, the causative agent of COVID-19 respiratory disease, has infected over 2.3 million people, killed over 160,000, and caused worldwide social and economic disruption1,2. There are currently no antiviral drugs with proven clinical efficacy, nor are there vaccines for its prevention, and these efforts are hampered by limited knowledge of the molecular details of SARS-CoV-2 infection. To address this, we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins physically associated with each using affinity-purification mass spectrometry (AP-MS), identifying 332 high-confidence SARS-CoV-2-human protein-protein interactions (PPIs). Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (29 FDA-approved drugs, 12 drugs in clinical trials, and 28 preclinical compounds). Screening a subset of these in multiple viral assays identified two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the Sigma1 and Sigma2 receptors. Further studies of these host factor targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19

    Effect of ECAP temperature on microstructure and mechanical properties of Al–Zn–Mg–Cu alloy

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    The effect of equal channel angular pressing (ECAP) at different temperatures (room temperature, 120, 150 and 180 °C) on microstructure and mechanical properties of Al-7075 solid solution alloy was investigated. Microstructure of the specimens was examined using orientation imaging microscopy, transmission electron microscopy as well as X-ray diffractometer, and mechanical properties were measured by Vickers microhardness and tensile tests. Microstructural investigations showed that after 3 or 4 passes of ECAP, fine grains with average grain sizes in range of 300–1000 nm could be obtained at different ECAP temperatures. Increasing ECAP temperature from 120 to 180 °C caused a decrease in mechanical properties as a result of increasing grains and precipitates sizes, decreasing fraction of high angle boundaries and also transformation of η′ into η phase, while increasing ECAP temperature from RT to 120 °C leads to an increase in mechanical properties due to the formation of small η′ precipitates. So it can be concluded that ECAP process at 120 °C is the optimum process for attaining maximum mechanical properties. Quantitative estimates of various strengthening mechanisms revealed that the improvement of mechanical properties was mainly attributed to grain refinement strengthening, precipitation strengthening and dislocation strengthening

    Legionella suppresses the host unfolded protein response via multiple mechanisms

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    © 2015 Macmillan Publishers Limited. All rights reserved.The intracellular pathogen, Legionella pneumophila, secretes ∼ 300 effector proteins to modulate the host environment. Given the intimate interaction between L. pneumophila and the endoplasmic retic

    Use of hydrological methods for assessment of environmental flow in a river reach

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    Environmental flow assessment and maintenance are relatively new practices, especially in developing countries. This paper describes the desktop assessment of environmental flows in a river with insufficient data on ecological features and values. In this study, the potential environmental flows in a typical river reach of the Shahr Chai River in Iran were investigated using a newly developed hydrological method (flow duration curve (FDC) shifting) and Global Environmental Flow Calculator software. This approach uses monthly flow data to develop an environmental FDC and to generate flow requirements corresponding to different features of the river ecosystem. Results were compared with those from four alternative hydrological methods: the desktop reserve model (DRM), Tennant, low-flow index, and flow duration curve analysis (FDCA). Comparisons of these methods indicated that to maintain the basic function of the river ecosystem, the river flows should be managed within an acceptable environmental level. The predictions from the Tennant method and the low-flow index (7-day low flow with a 10-year return period), and from the FDCA (for flows exceeding 90 % of occurrence) are not as reliable as those from the FDC shifting technique and DRM. Comparative results indicate that a minimum flow rate of 1.2 m3/s (equivalent to 23 % of the natural mean annual runoff, or flow with 80 % occurrence depicted from the FDC) is required for the Shahr Chai River to run toward the internationally recognized Urmia Lake in Iran

    Temperature Modeling with the Group Method of Data Handling to Inform Projected Rainfall Depth Changes for Extreme Events in Central West, New South Wales, Australia

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    The focus of this research is to introduce the application of the polynomial neural network of the group method of data handling (GMDH) for the first time in the regional area of the New South Wales state of Australia. Within this regional context, temperature data are modeled to assess its projected variation impacts on rainfall depth due to climate change. The study area encompasses six local government areas within the state’s Central West region. Stochastic methods for monotonic trend identification were used to support the modeling. Four established homogeneity tests were also used for assessing data integrity by determining the frequency of breakpoints within the mean of the data. The results of the GMDH modeling returned a coefficient of determination exceeding 0.9 for all stations dominated by an overall upward trend with an average maximum temperature increase of 0.459 °C per decade across the study region. The homogeneity tests found all data categorized as useful within the context of applicability for further climate change studies. By combining the modeled upward temperature trend with the intensity frequency distribution (IFD) design rainfall modification factor, projected depth increases by 2070 are obtained, enabling improved designs for stormwater infrastructure based on classified temperature variation scenarios
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