963 resultados para Definitive Hematopoiesis
Resumo:
In this study, we explore the population genetics of the Russian wheat aphid (RWA) (Diuraphis noxia), one of the world’s most invasive agricultural pests, in north-western China. We have analysed the data of 10 microsatellite loci and mitochondrial sequences from 27 populations sampled over 2 years in China. The results confirm that the RWAs are holocyclic in China with high genetic diversity indicating widespread sexual reproduction. Distinct differences in microsatellite genetic diversity and distribution revealed clear geographic isolation between RWA populations in northern and southern Xinjiang, China, with gene flow interrupted across extensive desert regions. Despite frequent grain transportation from north to south in this region, little evidence for RWA translocation as a result of human agricultural activities was found. Consequently, frequent gene flow among northern populations most likely resulted from natural dispersal, potentially facilitated by wind currents. We also found evidence for the longterm existence and expansion of RWAs in China, despite local opinion that it is an exotic species only present in China since 1975. Our estimated date of RWA expansion throughout China coincides with the debut of wheat domestication and cultivation practices in western Asia in the Holocene. We conclude that western China represents the limit of the far eastern native range of this species. This study is the most comprehensive molecular genetic investigation of the RWA in its native range undertaken to date and provides valuable insights into the history of the association of this aphid with domesticated cereals and wild grasses.
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Objective - this study examined the clinical utility and precision of routine screening for alcohol and other drug use among women attending a public antenatal service. Study design - a survey of clients and audit of clinical charts. Participants and setting - clients attending an antenatal clinic of a large tertiary hospital in Queensland, Australia, from October to December 2009. Measurements and findings - data were collected from two sources. First, 32 women who reported use of alcohol or other drugs during pregnancy at initial screening were then asked to complete a full substance use survey. Second, data were collected from charts of 349 new clients who attended the antenatal clinic during the study period. Both sensitivity (86%, 67%) and positive predictive value (100%, 92%) for alcohol and other drug use respectively, were high. Only 15% of surveyed women were uncomfortable about being screened for substance use in pregnancy, yet the chart audit revealed poor staff compliance. During the study period, 25% of clients were either not screened adequately or not at all. Key conclusions and implications for practise - despite recommended universal screening in pregnancy and the apparent acceptance by our participants, alcohol and other drug (A&OD) screening in the antenatal setting remains problematic. Investigation into the reasons behind, and ways to overcome, the low screening rate could improve health outcomes for mothers and children in this at-risk group. Targeted education and training for midwives may form part of the solution as these clinicians have a key role in implementing prevention and early intervention strategies.
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A qualitative approach was used to explore the impact of acculturation stress on the marital relationships of South Sudanese refugees settled in Brisbane, Australia. Thirteen refugees, who were currently or previously married, participated in three gender specific focus groups. The perceived causes and possible solutions of conflict were thoroughly explored. Hypothetical scenarios were used to facilitate group discussion. Major issues causing conflict between couples were identified as: the management of finances and lack of family and social support. Several other areas of acculturation stress also emerged as factors associated with marital stress. There was a dissonance regarding the adherence to cultural gender roles. Freedom provided to women in Australia caused tension between the couples. Law enforcement officers were perceived as lacking cultural understanding and misinterpreting the couple distress. Finally, limited information provided to refugees pre and post migration was considered to hinder adjustment. The participants suggested a number of practical solutions to these issues which are potentially useful in guiding future refugee settlement programs.
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A system is described for calculating volume from a sequence of multiplanar 2D ultrasound images. Ultrasound images are captured using a video digitising card (Hauppauge Win/TV card) installed in a personal computer, and regions of interest transformed into 3D space using position and orientation data obtained from an electromagnetic device (Polbemus, Fastrak). The accuracy of the system was assessed by scanning 10 water filled balloons (13-141 ml), 10 kidneys (147 200 ml) and 16 fetal livers (8 37 ml) in water using an Acuson 128XP/10 (5 MHz curvilinear probe). Volume was calculated using the ellipsoid, planimetry, tetrahedral and ray tracing methods and compared with the actual volume measured by weighing (balloons) and water displacement (kidneys and livers). The mean percentage error for the ray tracing method was 0.9 ± 2.4%, 2.7 ± 2.3%, 6.6 ± 5.4% for balloons, kidneys and livers, respectively. So far the system has been used clinically to scan fetal livers and lungs, neonate brain ventricles and adult prostate glands.
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Diaspora philanthropy is a popular buzzword; however, what the term encompasses or how institutionalised the phenomenon is remains an open question. There are as many views and definitions of diaspora philanthropy as there are diaspora communities involved. It is often seen as a potential source of funding for geographic regions, religions or ethnic communities globally. But identifying a framework for diaspora philanthropy is difficult. Unlike the literature on international philanthropy (including ethnic philanthropy and cross-border philanthropy), which has been a predominant topic of interest in recent years, the literature on diaspora philanthropy is scarce. There is a variety of opinion on what should and should not be considered under this scribe, which makes it impossible to provide a definitive description of diaspora philanthropy that suits everyone. The term “diaspora” has different meanings for different individuals and groups of people. Some see it as relating only to exiled and ejected communities of people; others use the term to refer to individuals or groups who are living in a new homeland whether by choice or circumstance. This paper defines “diaspora” in terms of an individual or group which identifies with an original homeland, (either theirs or a member of their family’s such as a grandparent), and is in the diaspora whether through their choice or a circumstance beyond their control. This obligatory identification towards a homeland differentiates this study on diaspora philanthropy from those that define it as an affiliation with a religious community and not necessarily a specific homeland.
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Until recently, standards to guide nursing education and practice in Vietnam were nonexistent. This paper describes the development and implementation of a clinical teaching capacity building project piloted in Hanoi, Vietnam. The project was part of a multi-component capacity building program designed to improve nurse education in Vietnam. Objectives of the project were to develop a collaborative clinically-based teaching model that encourages evidence-based, student-centred clinical learning. The model incorporated strategies to promote development of nursing practice to meet national competency standards. Thirty nurse teachers from two organisations in Hanoi participated in the program. These participants attended three workshops, and completed applied assessments, where participants implemented concepts from each workshop. The assessment tasks were planning, implementing and evaluating clinical teaching. On completion of the workshops, twenty participants undertook a study tour in Australia to refine the teaching model and develop an action plan for model implementation in both organisations, with an aim to disseminate the model across Vietnam. Significant changes accredited to this project have been noted on an individual and organisational level. Dissemination of this clinical teaching model has commenced in Ho Chi Minh, with further plans for more in-depth dissemination to occur throughout the country.
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Using Gray and McNaughton’s (2000) revised Reinforcement Sensitivity Theory (r-RST), we examined the influence of personality on processing of words presented in gain-framed and loss-framed anti-speeding messages and how the processing biases associated with personality influenced message acceptance. The r-RST predicts that the nervous system regulates personality and that behaviour is dependent upon the activation of the Behavioural Activation System (BAS), activated by reward cues and the Fight-Flight-Freeze System (FFFS), activated by punishment cues. According to r-RST, individuals differ in the sensitivities of their BAS and FFFS (i.e., weak to strong), which in turn leads to stable patterns of behaviour in the presence of rewards and punishments, respectively. It was hypothesised that individual differences in personality (i.e., strength of the BAS and the FFFS) would influence the degree of both message processing (as measured by reaction time to previously viewed message words) and message acceptance (measured three ways by perceived message effectiveness, behavioural intentions, and attitudes). Specifically, it was anticipated that, individuals with a stronger BAS would process the words presented in the gain-frame messages faster than those with a weaker BAS and individuals with a stronger FFFS would process the words presented in the loss-frame messages faster than those with a weaker FFFS. Further, it was expected that greater processing (faster reaction times) would be associated with greater acceptance for that message. Driver licence holding students (N = 108) were recruited to view one of four anti-speeding messages (i.e., social gain-frame, social loss-frame, physical gain-frame, and physical loss-frame). A computerised lexical decision task assessed participants’ subsequent reaction times to message words, as an indicator of the extent of processing of the previously viewed message. Self-report measures assessed personality and the three message acceptance measures. As predicted, the degree of initial processing of the content of the social gain-framed message mediated the relationship between the reward sensitive trait and message effectiveness. Initial processing of the physical loss-framed message partially mediated the relationship between the punishment sensitive trait and both message effectiveness and behavioural intention ratings. These results show that reward sensitivity and punishment sensitivity traits influence cognitive processing of gain-framed and loss-framed message content, respectively, and subsequently, message effectiveness and behavioural intention ratings. Specifically, a range of road safety messages (i.e., gain-frame and loss-frame messages) could be designed which align with the processing biases associated with personality and which would target those individuals who are sensitive to rewards and those who are sensitive to punishments.
Resumo:
Surface coating with an organic self-assembled monolayer (SAM) can enhance surface reactions or the absorption of specific gases and hence improve the response of a metal oxide (MOx) sensor toward particular target gases in the environment. In this study the effect of an adsorbed organic layer on the dynamic response of zinc oxide nanowire gas sensors was investigated. The effect of ZnO surface functionalisation by two different organic molecules, tris(hydroxymethyl)aminomethane (THMA) and dodecanethiol (DT), was studied. The response towards ammonia, nitrous oxide and nitrogen dioxide was investigated for three sensor configurations, namely pure ZnO nanowires, organic-coated ZnO nanowires and ZnO nanowires covered with a sparse layer of organic-coated ZnO nanoparticles. Exposure of the nanowire sensors to the oxidising gas NO2 produced a significant and reproducible response. ZnO and THMA-coated ZnO nanowire sensors both readily detected NO2 down to a concentration in the very low ppm range. Notably, the THMA-coated nanowires consistently displayed a small, enhanced response to NO2 compared to uncoated ZnO nanowire sensors. At the lower concentration levels tested, ZnO nanowire sensors that were coated with THMA-capped ZnO nanoparticles were found to exhibit the greatest enhanced response. ΔR/R was two times greater than that for the as-prepared ZnO nanowire sensors. It is proposed that the ΔR/R enhancement in this case originates from the changes induced in the depletion-layer width of the ZnO nanoparticles that bridge ZnO nanowires resulting from THMA ligand binding to the surface of the particle coating. The heightened response and selectivity to the NO2 target are positive results arising from the coating of these ZnO nanowire sensors with organic-SAM-functionalised ZnO nanoparticles.
Resumo:
A 4-cylinder Ford 2701C test engine was used in this study to explore the impact of ethanol fumigation on gaseous and particle emission concentrations. The fumigation technique delivered vaporised ethanol into the intake manifold of the engine, using an injector, a pump and pressure regulator, a heat exchanger for vaporising ethanol and a separate fuel tank and lines. Gaseous (Nitric oxide (NO), Carbon monoxide (CO) and hydrocarbons (HC)) and particulate emissions (particle mass (PM2.5) and particle number) testing was conducted at intermediate speed (1700 rpm) using 4 load settings with ethanol substitution percentages ranging from 10-40 % (by energy). With ethanol fumigation, NO and PM2.5 emissions were reduced, whereas CO and HC emissions increased considerably and particle number emissions increased at most test settings. It was found that ethanol fumigation reduced the excess air factor for the engine and this led to increased emissions of CO and HC, but decreased emissions of NO. PM2.5 emissions were reduced with ethanol fumigation, as ethanol has a very low “sooting” tendency. This is due to the higher hydrogen-to-carbon ratio of this fuel, and also because ethanol does not contain aromatics, both of which are known soot precursors. The use of a diesel oxidation catalyst (as an after-treatment device) is recommended to achieve a reduction in the four pollutants that are currently regulated for compression ignition engines. The increase in particle number emissions with ethanol fumigation was due to the formation of volatile (organic) particles; consequently, using a diesel oxidation catalyst will also assist in reducing particle number emissions.
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Nineteen studies met the inclusion criteria. A skin temperature reduction of 5–15 °C, in accordance with the recent PRICE (Protection, Rest, Ice, Compression and Elevation) guidelines, were achieved using cold air, ice massage, crushed ice, cryotherapy cuffs, ice pack, and cold water immersion. There is evidence supporting the use and effectiveness of thermal imaging in order to access skin temperature following the application of cryotherapy. Thermal imaging is a safe and non-invasive method of collecting skin temperature. Although further research is required, in terms of structuring specific guidelines and protocols, thermal imaging appears to be an accurate and reliable method of collecting skin temperature data following cryotherapy. Currently there is ambiguity regarding the optimal skin temperature reductions in a medical or sporting setting. However, this review highlights the ability of several different modalities of cryotherapy to reduce skin temperature.
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Product innovation is an important contributor to the performance of infrastructure projects in the construction industry. Maximizing the potential for innovative product adoption is a challenging task due to the complexities of the construction innovation system. A qualitative methodology involving interviews with major construction project stakeholders is employed to address the research question: ‘What are the main obstacles to the adoption of innovative products in the road industry?’ The characteristics of six key product innovation obstacles in Australian road projects are described. The six key obstacles are: project goal misalignment, client pressures, weak contractual relations, lack of product trialling, inflexible product specifications and product liability concerns. A snapshot of the dynamics underlying these obstacles is provided. There are few such assessments in the literature, despite the imperative to improve construction innovation rates globally in order to deliver road infrastructure projects of increasing size and complexity. Key obstacles are interpreted through an open innovation construct, providing direction for policy to enhance the uptake of innovation across the construction product supply network. Early evidence suggests the usefulness of an open innovation construct that integrates three conceptual lenses: network governance, absorptive capacity and knowledge intermediation, in order to interpret product adoption obstacles in the context of Australian road infrastructure projects. The paper also provides practical advice and direction for government and industry organizations that wish to promote the flow of innovative product knowledge across the construction supply network.
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Nekoite Ca3Si6O15•7H2O and okenite Ca10Si18O46•18H2O are both hydrated calcium silicates found respectively in contact metamorphosed limestone and in association with zeolites from the alteration of basalts. The minerals form two-Dimensional infinite sheets with other than six-membered rings with 3-, 4-, or 5-membered rings and 8-membered rings. The two minerals have been characterised by Raman, near-infrared and infrared spectroscopy. The Raman spectrum of nekoite is characterised by two sharp peaks at 1061 and 1092 cm-1 with bands of lesser intensity at 974, 994, 1023 and 1132 cm-1. The Raman spectrum of okenite shows an intense single Raman band at 1090 cm-1 with a shoulder band at 1075 cm-1.These bands are assigned to the SiO stretching vibrations of Si2O5 units. Raman water stretching bands of nekoite are observed at 3071, 3380, 3502 and 3567 cm-1. Raman spectrum of okenite shows water stretching bands at 3029, 3284, 3417, 3531 and 3607 cm-1. NIR spectra of the two minerals are subtly different inferring water with different hydrogen bond strengths. By using a Libowitzky empirical formula, hydrogen bond distances based upon these OH stretching vibrations. Two types of hydrogen bonds are distinguished: strong hydrogen bonds associated with structural water and weaker hydrogen bonds assigned to space filling water molecules.
Resumo:
This study reports on the gas sensing characteristics of Fe-doped (10 at.%) tungsten oxide thin films of various thicknesses (100–500 nm) prepared by electron beam evaporation. The performance of these films in sensing four gases (H2, NH3, NO2 and N2O) in the concentration range 2–10,000 ppm at operating temperatures of 150–280 °C has been investigated. The results are compared with the sensing performance of a pure WO3 film of thickness 300 nm produced by the same method. Doping of the tungsten oxide film with 10 at.% Fe significantly increases the base conductance of the pure film but decreases the gas sensing response. The maximum response measured in this experiment, represented by the relative change in resistance when exposed to a gas, was ΔR/R = 375. This was the response amplitude measured in the presence of 5 ppm NO2 at an operating temperature of 250 °C using a 400 nm thick WO3:Fe film. This value is slightly lower than the corresponding result obtained using the pure WO3 film (ΔR/R = 450). However it was noted that the WO3:Fe sensor is highly selective to NO2, exhibiting a much higher response to NO2 compared to the other gases. The high performance of the sensors to NO2 was attributed to the small grain size and high porosity of the films, which was obtained through e-beam evaporation and post-deposition heat treatment of the films at 300 °C for 1 h in air.
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This paper presents a behavioral car-following model based on empirical trajectory data that is able to reproduce the spontaneous formation and ensuing propagation of stop-and-go waves in congested traffic. By analyzing individual drivers’ car-following behavior throughout oscillation cycles it is found that this behavior is consistent across drivers and can be captured by a simple model. The statistical analysis of the model’s parameters reveals that there is a strong correlation between driver behavior before and during the oscillation, and that this correlation should not be ignored if one is interested in microscopic output. If macroscopic outputs are of interest, simulation results indicate that an existing model with fewer parameters can be used instead. This is shown for traffic oscillations caused by rubbernecking as observed in the US 101 NGSIM dataset. The same experiment is used to establish the relationship between rubbernecking behavior and the period of oscillations.
Resumo:
Serving as a powerful tool for extracting localized variations in non-stationary signals, applications of wavelet transforms (WTs) in traffic engineering have been introduced; however, lacking in some important theoretical fundamentals. In particular, there is little guidance provided on selecting an appropriate WT across potential transport applications. This research described in this paper contributes uniquely to the literature by first describing a numerical experiment to demonstrate the shortcomings of commonly-used data processing techniques in traffic engineering (i.e., averaging, moving averaging, second-order difference, oblique cumulative curve, and short-time Fourier transform). It then mathematically describes WT’s ability to detect singularities in traffic data. Next, selecting a suitable WT for a particular research topic in traffic engineering is discussed in detail by objectively and quantitatively comparing candidate wavelets’ performances using a numerical experiment. Finally, based on several case studies using both loop detector data and vehicle trajectories, it is shown that selecting a suitable wavelet largely depends on the specific research topic, and that the Mexican hat wavelet generally gives a satisfactory performance in detecting singularities in traffic and vehicular data.