653 research outputs found
Being a non-drinking student: an interpretative phenomenological analysis
Recent research suggests that safer student alcohol consumption might be assisted by understanding how social occasions are managed by non-drinkers. In-depth, semi-structured interviews with five 19-22 year old non-drinking English undergraduates were subjected to interpretative phenomenological analysis (IPA). We present five inter-linked themes: ‘living with challenges to non drinking’; ‘seeing what goes on in drinking environments’; ‘dealing with conversations about non-drinking (‘making excuses vs. coming out’)’; ‘knowing which
friends care about you’; and ‘the importance of withholding “legroom” for peer pressure’. Participants felt under persistent peer scrutiny (as a form of peer pressure) and could feel alienated in drinking environments. Talking about non-drinking was characterised by whether to ‘come out’ (as a non-drinker) or ‘fake it’ (e.g., ‘I’m on antibiotics’). Loyal friendships were reported as particularly important in this context. The decision not to drink was experienced as providing a successful buffer to peer pressure for former drinkers. Our findings unsettle
traditional health promotion campaigns which advocate moderate drinking among students without always suggesting how it might be most successfully accomplished, and offer
tentative guidance on how non-drinking during specific social occasions might be managed more successfully. Findings are discussed in relation to extant literature and future research directions are suggested
Range imager performance comparison in homodyne and heterodyne operating modes
Range imaging cameras measure depth simultaneously for every pixel in a given field of view. In most implementations the basic operating principles are the same. A scene is illuminated with an intensity modulated light source and the reflected signal is sampled using a gain-modulated imager. Previously we presented a unique heterodyne range imaging system that employed a bulky and power hungry image intensifier as the high speed gain-modulation mechanism. In this paper we present a new range imager using an internally modulated image sensor that is designed to operate in heterodyne mode, but can also operate in homodyne mode. We discuss homodyne and heterodyne range imaging, and the merits of the various types of hardware used to implement these systems. Following this we describe in detail the hardware and firmware components of our new ranger. We experimentally compare the two operating modes and demonstrate that heterodyne operation is less sensitive to some of the limitations suffered in homodyne mode, resulting in better linearity and ranging precision characteristics. We conclude by showing various qualitative examples that demonstrate the system’s three-dimensional measurement performance
Breaking the Silence:Career Guidance for Self-Initiated International Placement Students”
PurposeSelf-initiated international placements by students have been largely ignored in the literature on outward mobility in higher education. The support given to self-initiated international placement students, if any, has received even less attention. This study aims to address this lacuna.Design/methodology/approachDrawing on insights from global mobility literature, we conducted a survey of UK university students who engaged in self-initiated international placements to various countries such as France, China, Brazil and Ghana. Data were analysed using descriptive statistics and thematic content analysis.FindingsFindings reveal that these “voluntary” placements can improve language fluency, increase self-confidence, renew stress management abilities and enhance cross-cultural competencies and intercultural sensitivity. The study problematises the lack of support given to these students particularly in terms of career development.Originality/valueOur paper is one of the first to bring this under-studied population to the attention of career guidance scholars. We propose that scholarly attention should be directed toward the agency of self-initiated international placement students and that targeted career guidance must be provided through more inclusive career services
Shape and deformation measurement using heterodyne range imaging technology
Range imaging is emerging as a promising alternative technology for applications that require non-contact visual inspection of object deformation and shape. Previously, we presented a solid-state full-field heterodyne range imaging device capable of capturing three-dimensional images with sub-millimetre range resolution. Using a heterodyne indirect time-of-flight configuration, this system simultaneously measures distance (and intensity), for each pixel in a cameras field of view. In this paper we briefly describe our range imaging system, and its principle of operation. By performing measurements on several metal objects, we demonstrate the potential capabilities of this technology for surface profiling and deformation measurement. In addition to verifying system performance, the reported examples highlight some important system limitations. With these in mind we subsequently discuss the further developments required to enable the use of this device as a robust and practical tool in non-destructive testing and measurement applications
A power-saving modulation technique for time-of-flight range imaging sensors
Time-of-flight range imaging cameras measure distance and intensity simultaneously for every pixel in an image. With the continued advancement of the technology, a wide variety of new depth sensing applications are emerging; however a number of these potential applications have stringent electrical power constraints that are difficult to meet with the current state-of-the-art systems. Sensor gain modulation contributes a significant proportion of the total image sensor power consumption, and as higher spatial resolution range image sensors operating at higher modulation frequencies (to achieve better measurement precision) are developed, this proportion is likely to increase. The authors have developed a new sensor modulation technique using resonant circuit concepts that is more power efficient than the standard mode of operation. With a proof of principle system, a 93–96% reduction in modulation drive power was demonstrated across a range of modulation frequencies from 1–11 MHz. Finally, an evaluation of the range imaging performance revealed an improvement in measurement linearity in the resonant configuration due primarily to the more sinusoidal shape of the resonant electrical waveforms, while the average precision values were comparable between the standard and resonant operating modes
The Waikato range imager
We are developing a high precision simultaneous full-field acquisition range imager. This device measures range with sub millimetre precision in range simultaneously over a full-field view of the scene. Laser diodes are used to illuminate the scene with amplitude modulation with a frequency of 10MHz up to 100 MHz. The received light is interrupted by a high speed shutter operating in a heterodyne configuration thus producing a low-frequency signal which is sampled with a digital camera. By detecting the phase of the signal at each pixel the range to the scene is determined. We show 3D reconstructions of some viewed objects to demonstrate the capabilities of the ranger
Heterodyne range imaging as an alternative to photogrammetry
Solid-state full-field range imaging technology, capable of determining the distance to objects in a scene simultaneously for every pixel in an image, has recently achieved sub-millimeter distance measurement precision. With this level of precision, it is becoming practical to use this technology for high precision three-dimensional metrology applications. Compared to photogrammetry, range imaging has the advantages of requiring only one viewing angle, a relatively short measurement time, and simplistic fast data processing. In this paper we fist review the range imaging technology, then describe an experiment comparing both photogrammetric and range imaging measurements of a calibration block with attached retro-reflective targets. The results show that the range imaging approach exhibits errors of approximately 0.5 mm in-plane and almost 5 mm out-of-plane; however, these errors appear to be mostly systematic. We then proceed to examine the physical nature and characteristics of the image ranging technology and discuss the possible causes of these systematic errors. Also discussed is the potential for further system characterization and calibration to compensate for the range determination and other errors, which could possibly lead to three-dimensional measurement precision approaching that of photogrammetry
Video-rate or high-precision: A flexible range imaging camera
A range imaging camera produces an output similar to a digital photograph, but every pixel in the image contains distance information as well as intensity. This is useful for measuring the shape, size and location of objects in a scene, hence is well suited to certain machine vision applications.
Previously we demonstrated a heterodyne range imaging system operating in a relatively high resolution (512-by-512) pixels and high precision (0.4 mm best case) configuration, but with a slow measurement rate (one every 10 s). Although this high precision range imaging is useful for some applications, the low acquisition speed is limiting in many situations. The system’s frame rate and length of acquisition is fully configurable in software, which means the measurement rate can be increased by compromising precision and image resolution.
In this paper we demonstrate the flexibility of our range imaging system by showing examples of high precision ranging at slow acquisition speeds and video-rate ranging with reduced ranging precision and image resolution. We also show that the heterodyne approach and the use of more than four samples per beat cycle provides better linearity than the traditional homodyne quadrature detection approach. Finally, we comment on practical issues of frame rate and beat signal frequency selection
Evaluating the ability of citizen scientists to identify bumblebee (Bombus) species
Citizen science is an increasingly popular way of engaging volunteers in the collection of scientific data. Despite this, data quality remains a concern and there is little published evidence about the accuracy of records generated by citizen scientists. Here we compare data generated by two British citizen science projects, Blooms for Bees and BeeWatch, to determine the ability of volunteer recorders to identify bumblebee (Bombus) species. We assessed recorders' identification ability in two ways-as recorder accuracy (the proportion of expert-verified records correctly identified by recorders) and recorder success (the proportion of recorder-submitted identifications confirmed correct by verifiers). Recorder identification ability was low (<50% accuracy; <60% success), despite access to project specific bumblebee identification materials. Identification ability varied significantly depending on bumblebee species, with recorders most able to correctly identify species with distinct appearances. Blooms for Bees recorders (largely recruited from the gardening community) were markedly less able to identify bumblebees than BeeWatch recorders (largely individuals with a more specific interest in bumblebees). Within both projects, recorders demonstrated an improvement in identification ability over time. Here we demonstrate and quantify the essential role of expert verification within citizen science projects, and highlight where resources could be strengthened to improve recorder ability
Electrochemiluminescence platform for the detection of C-reactive proteins : application of recombinant antibody technology to cardiac biomarker detection
This work exploits the high-affinity of recombinant antibodies and low background electrochemiluminescence (ECL) for cardiac-biomarker detection. The developed assay is capable of fg mL-1 detection limits as well as the detection of C-Reactive Protein (CRP) over a clinically relevant range. The assay demonstrated robust reproducibility, selectivity and stability while also highlighting a novel platform for detection of cardiac biomarkers at low concentrations
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