991 resultados para Sediment Characteristics
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Floods through inundated urban environments constitute a hazard to the population and infrastructure. A series of field measurements were performed in an inundated section of the City of Brisbane (Australia) during a major flood in January 2011. Using an acoustic Doppler velocimeter (ADV), detailed velocity and suspended sediment concentration measurements were conducted about the peak of the flood. The results are discussed with a focus on the safety of individuals in floodwaters and the sediment deposition during the flood recession. The force of the floodwaters in Gardens Point Road was deemed unsafe for individual evacuation. A comparison with past laboratory results suggested that previous recommendations could be inappropriate and unsafe in real flood flows.
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Background A population-based, cross-sectional telephone survey was conducted to estimate the penetrance and characteristics of contact lens wear in Australia. Methods Based on postcode distribution, 42,749 households around Australia were randomly selected from the national electronic telephone directory. During calls, the number of individuals and contact lens wearers in each household aged between 15 and 64 years was ascertained. Contact lens wearers were interviewed using a structured questionnaire, to determine details of demographics, lens type, mode of lens wear and hygienic habits. Contact lens wear characteristics and habits were compared by lens type and mode of use. Results Of the 32,405 households contacted, 19,171 (59.2 per cent) agreed to participate. The penetrance of contact lens wear during the study period was 5.01 per cent (95% CI: 4.78-5.24). The mean age of lens wearers was 36.5 ± 18.3 years and 63.4 per cent were female. There were significant differences in the habits and characteristics of lens wearers depending on their lens type and mode of use. Conclusions The penetrance of contact lens wear concurs with market estimates and equates to approximately 680,000 contact lens wearers aged between 15 and 64 years in Australia. This is the most detailed and extensive population-based survey of contact lens wearers ever conducted. The discrepancies found between the characteristics of lens wearers surveyed in this study compared to those in previous studies of contact lens practitioners highlights the importance of study design. These results may be applied to other regions with similar health-care and regulatory systems.
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This research has developed an innovative road safety barrier system that will enhance roadside safety. In doing so, the research developed new knowledge in the field of road crash mitigation for high speed vehicle impact involving plastic road safety barriers. This road safety barrier system has the required feature to redirecting an errant vehicle with limited lateral displacement. Research was carried out using dynamic computer simulation technique support by experimental testing. Future road safety barrier designers may use the information in this research as a design guideline to improve the performance and redirectional capability of the road safety barrier system. This will lead to better safety conditions on the roadways and potentially save lives.
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Study Design Cross-sectional study. Objective To explore aspects of cervical musculoskeletal function in female office workers with neck pain. Summary of Background Data Evidence of physical characteristics that differentiate computer workers with and without neck pain is sparse. Patients with chronic neck pain demonstrate reduced motion and altered patterns of muscle control in the cervical flexor and upper trapezius (UT) muscles during specific tasks. Understanding cervical musculoskeletal function in office workers will better direct intervention and prevention strategies. Methods Measures included neck range of motion; superficial neck flexor muscle activity during a clinical test, the craniocerivcal flexion test; and a motor task, a unilateral muscle coordination task, to assess the activity of both the anterior and posterior neck muscles. Office workers with and without neck pain were formed into 3 groups based on their scores on the Neck Disability Index. Nonworking women without neck pain formed the control group. Surface electromyographic activity was recorded bilaterally from the sternocleidomastoid, anterior scalene (AS), cervical extensor (CE) and UT muscles. Results Workers with neck pain had reduced rotation range and increased activity of the superficial cervical flexors during the craniocervical flexion test. During the coordination task, workers with pain demonstrated greater activity in the CE muscles bilaterally. On completion of the task, the UT and dominant CE and AS muscles demonstrated an inability to relax in workers with pain. In general, there was a linear relationship between the workers’ self-reported levels of pain and disability and the movement and muscle changes. Conclusion These results are consistent with those found in other cervical musculoskeletal disorders and may represent an altered muscle recruitment strategy to stabilize the head and neck. An exercise program including motor reeducation may assist in the management of neck pain in office workers.
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We investigate how email users' characteristics influence their response to phishing emails. A user generally goes through three stages of behaviour upon receiving a phishing email: suspicion of the legitimacy of the email, confirmation of its legitimacy and response by either performing the action requested in the phishing email or not. Using a mixed method approach combining experiments, surveys and semi-structured interviews, we found that a user's behaviour at each stage varies with their personal characteristics such as personality traits and ability to perceive information in an email beyond its content. We found, for example, that users who are submissive, extraverted or open tend to be less suspicious of phishing emails while users who can identify cues such as inconsistent IP address, can avoid falling victim to phishing emails. Our findings enable us to draw practical implications for educating and potentially reducing the incidence of phishing emails victimisation.
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Anisometropia represents a unique example of ocular development, where the two eyes of an individual, with an identical genetic background and seemingly subject to identical environmental influences, can grow asymmetrically to produce significantly different refractive errors. This review provides an overview of the research examining myopic anisometropia, the ocular characteristics underlying the condition and the potential aetiological factors involved. Various mechanical factors are discussed, including corneal structure, intraocular pressure and forces generated during near work that may contribute to development of anisomyopia. Potential visually guided mechanisms of unequal ocular growth are also explored, including the influence of astigmatism, accommodation, higher-order aberrations and the choroidal response to altered visual experience. The association between binocular vision, ocular dominance and asymmetric refraction is also considered, along with a review of the genetic contribution to the aetiology of myopic anisometropia. Despite a significant amount of research into the biomechanical, structural and optical characteristics of anisometropic eyes, there is still no unifying theory, which adequately explains how two eyes within the same visual system grow to different endpoints.
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The aim of this work was to investigate changes in particle number concentration (PNC) within naturally ventilated primary school classrooms arising from local sources either within or adjacent to the classrooms. We quantify the rate at which ultrafine particles were emitted either from printing, grilling, heating or cleaning activities and the rate at which the particles were removed by both deposition and air exchange processes. At each of 25 schools in Brisbane, Australia, two weeks of measurements of PNC and CO2 were taken both outdoors and in the two classrooms. Bayesian regression modelling was employed in order to estimate the relevant rates and analyse the relationship between air exchange rate (AER), particle infiltration and the deposition rates of particle generated from indoor activities in the classrooms. During schooling hours, grilling events at the school tuckshop as well as heating and printing in the classrooms led to indoor PNCs being elevated by a factor of more than four, with emission rates of (2.51 ± 0.25) x 1011 p min-1, (8.99 ± 6.70) x 1011 p min-1 and (5.17 ± 2.00) x 1011 p min-1, respectively. During non-school hours, cleaning events elevated indoor PNC by a factor of above five, with an average emission rate of (2.09 ± 6.30) x 1011 p min-1. Particles were removed by both air exchange and deposition; chiefly by ventilation when AER > 0.7 h-1 and by deposition when AER < 0.7 h-1.
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The relationship between public transportation and home values has proven to be complex, with studies providing divergent findings. Using Victorian Valuer General Data for 2009, this paper applies a hedonic pricing approach to the Melbourne metropolitan housing market in order to estimate the impacts of proximity to a train station on residential property prices. The findings reveal a negative impact on dwelling price for those properties within 125 metres from a train station and a positive relationship between dwelling price and proximity for properties more than 125 metres away.
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The present study compares the effects of two different material processing techniques on modifying hydrophilic SiO2 nanoparticles. In one method, the nanoparticles undergo plasma treatment by using a custom-developed atmospheric-pressure non-equilibrium plasma reactor. With the other method, they undergo chemical treatment which grafts silane groups onto their surface and turns them into hydrophobic. The treated nanoparticles are then used to synthesize epoxy resin-based nanocomposites for electrical insulation applications. Their characteristics are investigated and compared with the pure epoxy resin and nanocomposite fabricated with unmodified nanofillers counterparts. The dispersion features of the nanoparticles in the epoxy resin matrix are examined through scanning electron microscopy (SEM) images. All samples show evidence that the agglomerations are smaller than 30 nm in their diameters. This indicates good dispersion uniformity. The Weibull plot of breakdown strength and the recorded partial discharge (PD) events of the epoxy resin/plasma-treated hydrophilic SiO2 nanocomposite (ER/PTI) suggest that the plasma-treated specimen yields higher breakdown strength and lower PD magnitude as compared to the untreated ones. In contrast, surprisingly, lower breakdown strength is found for the nanocomposite made by the chemically treated hydrophobic particles, whereas the PD magnitude and PD numbers remain at a similar level as the plasma-treated ones.
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Background Current treatment of ovarian cancer patients with chemotherapy leaves behind a residual tumor which results in recurrent ovarian cancer within a short time frame. We have previously demonstrated that a single short-term treatment of ovarian cancer cells with chemotherapy in vitro resulted in a cancer stem cell (CSC)-like enriched residual population which generated significantly greater tumor burden compared to the tumor burden generated by control untreated cells. In this report we looked at the mechanisms of the enrichment of CSC-like residual cells in response to paclitaxel treatment. Methods The mechanism of survival of paclitaxel-treated residual cells at a growth inhibitory concentration of 50% (GI50) was determined on isolated tumor cells from the ascites of recurrent ovarian cancer patients and HEY ovarian cancer cell line by in vitro assays and in a mouse xenograft model. Results Treatment of isolated tumor cells from the ascites of ovarian cancer patients and HEY ovarian cancer cell line with paclitaxel resulted in a CSC-like residual population which coincided with the activation of Janus activated kinase 2 (JAK2) and signal transducer and activation of transcription 3 (STAT3) pathway in paclitaxel surviving cells. Both paclitaxel-induced JAK2/STAT3 activation and CSC-like characteristics were inhibited by a low dose JAK2-specific small molecule inhibitor CYT387 (1 μM) in vitro. Subsequent, in vivo transplantation of paclitaxel and CYT387-treated HEY cells in mice resulted in a significantly reduced tumor burden compared to that seen with paclitaxel only-treated transplanted cells. In vitro analysis of tumor xenografts at protein and mRNA levels demonstrated a loss of CSC-like markers and CA125 expression in paclitaxel and CYT387-treated cell-derived xenografts, compared to paclitaxel only-treated cell-derived xenografts. These results were consistent with significantly reduced activation of JAK2 and STAT3 in paclitaxel and CYT387-treated cell-derived xenografts compared to paclitaxel only-treated cell derived xenografts. Conclusions This proof of principle study demonstrates that inhibition of the JAK2/STAT3 pathway by the addition of CYT387 suppresses the ‘stemness’ profile in chemotherapy-treated residual cells in vitro, which is replicated in vivo, leading to a reduced tumor burden. These findings have important implications for ovarian cancer patients who are treated with taxane and/or platinum-based therapies. Keywords: Ovarian carcinoma, Cancer stem cell, Metastasis, Ascites, Chemoresistance, Recurrence, JAK2/STAT3 pathway
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Early full-term pregnancy is one of the most effective natural protections against breast cancer. To investigate this effect, we have characterized the global gene expression and epigenetic profiles of multiple cell types from normal breast tissue of nulliparous and parous women and carriers of BRCA1 or BRCA2 mutations. We found significant differences in CD44+ progenitor cells, where the levels of many stem cell-related genes and pathways, including the cell-cycle regulator p27, are lower in parous women without BRCA1/BRCA2 mutations. We also noted a significant reduction in the frequency of CD44+p27+ cells in parous women and showed, using explant cultures, that parity-related signaling pathways play a role in regulating the number of p27+ cells and their proliferation. Our results suggest that pathways controlling p27+ mammary epithelial cells and the numbers of these cells relate to breast cancer risk and can be explored for cancer risk assessment and prevention.
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Carbon microcoils (CMCs) have been coated with a Ni nanoparticle film using an electroless plating process. The morphology, the elemental composition and the phases in the coating layer, complex permittivity and permeability of the CMCs and Ni-coated CMCs were, respectively, investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and microwave vector network analysis at room temperature. A homogeneous dispersion of Ni nanoparticles on the outer surface of the CMCs was obtained, with a mean particle size of ∼34.4 nm and the phosphorus content of about 8.5 wt%. When comparing the coated and uncoated CMC samples, the real (ε′) and imaginary (ε″) part of the complex permittivity as well as dielectric dissipation factor (tgδε = ε″/ε′) of the Ni-coated CMCs were much smaller, while the real (μ′) and imaginary (μ″) part of the complex permeability and the magnetic dissipation factor (t g σμ = μ″ / μ′) were larger. The enhanced microwave absorption of Ni-coated CMCs resulted from stronger dielectric and magnetic losses. In contrast, the microwave absorption of uncoated CMCs was mainly attributed to the dielectric rather than magnetic losses.
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An attempt was made to investigate the optical emission spectra of atomic, molecular, and ionic species in low-frequency, high-density ICP discharges in pure nitrogen, ar con gases, and gas mixtures Ar+H2, N2+Ar, and N2+H2. The excited species were identified by in situ optical emission intensity (OEI) measurements in the discharge chamber. In general, significant results were obtained.
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Dispersion characteristics and topography of electromagnetic fields of axially symmetric surface waves (SW) and of azimuth surface waves (ASW) propagating in a structure composed of a cylindrical metal antenna and magnetoactive plasma are investigated. The antenna and plasma may be separated by a vacuum layer. The dispersion characteristics of SW and ASW are presented as functions of the antenna and the magnetoactive plasma parameters. Close agreement between theory and experimental results are shown. Surface impedances of the SW and ASW are calculated for various parameters of the problem.