440 research outputs found

    The aquatic basis of ancient civilisations: the case of Synodontis schall and the Nile Valley

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    This chapter focuses on the role of aquatic resources in the ancient economies of the Nile Valley. We suggest that these resources have been overlooked in traditional interpretations because of a reliance on wall paintings and carvings in tombs, assumptions about the dominance of cereal crops, and a dearth of well-excavated faunal assemblages from settlement sites. We focus on the faunal material from Tell el- Amarna and in particular the fish remains, which are dominated by the catfish, Synodontis schall. We show that, in conjunction with the study of modern control samples, we can obtain reliable estimates of age-at-death and size from growth increments in the pectoral spines, and thus analyse the age and size distribution of fish caught and their growth rates. As might be expected, the modern schall populations show evidence for more intensive fishing pressure than the ancient populations. Unexpectedly, however, the Roman material suggests that schall were exploited more intensively than in the preceding Dynastic period, and that they suffered lower growth rates. We argue that the slower growth rates are the result of climatic deterioration in the 6th century AD, and that the increased pressure on schall may reflect a decline in food supplies from other sources and a need for greater reliance on the fish resources of the river

    Voices emerging from the shadows : Radiologic practitioners’ experiences of challenging conversations

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    Objective Traditionally, radiologists have practiced their profession behind the scenes. Today, radiologic practitioners face mounting expectations to communicate more directly with patients. However, their experiences with patient communication are not well understood. The aim of this study was to describe the challenges of radiologic practitioners when communicating with patients. Methods Twelve day-long interprofessional communication skills workshops for radiologic clinicians were held at Boston Children\u2019s Hospital. Prior to each workshop, participants were asked to write narratives describing experiences with difficult radiologic conversations that they found particularly challenging or satisfying. The narratives were transcribed and analyzed through thematic content analysis by two researchers. Results Radiologists, radiology trainees, technologists, nurses, and medical interpreters completed 92 narratives. The most challenging aspects of healthcare conversations included: Conveying Serious News (n = 44/92; 48%); Expanded Scope of Radiologic Practice (n = 37/92; 40%); Inexperience and Gaps in Education (n = 15/92; 16%); Clinical Uncertainty (n = 14/92; 15%); and Interprofessional Teamwork (n = 9/92; 10%). Conclusion Radiologic clinicians face substantial communicative challenges focused on conveying serious, unexpected and uncertain diagnoses amid practical challenges and limited educational opportunities. Practice implications Innovative educational curricula that address these challenges may enhance radiologic practitioners\u2019 success in adopting patient-centered communication

    Dealing with mobility: Understanding access anytime, anywhere

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    The rapid and accelerating move towards the adoption and use of mobile technologies has increasingly provided people and organisations with the ability to work away from the office and on the move. The new ways of working afforded by these technologies are often characterised in terms of access to information and people ‘anytime, anywhere’. This paper presents a study of mobile workers that highlights different facets of access to remote people and information, and different facets of anytime, anywhere. Four key factors in mobile work are identified from the study: the role of planning, working in ‘dead time’, accessing remote technological and informational resources, and monitoring the activities of remote colleagues. By reflecting on these issues, we can better understand the role of technology and artefact use in mobile work and identify the opportunities for the development of appropriate technological solutions to support mobile workers

    Integrated optical Mach-Zehnder interferometer as simazine immunoprobe

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    Immunoassay has become a versatile tool in several fields of analytical chemistry. We describe the characterization and the application of different integrated optical channel waveguide Mach-Zehnder interferometers (MZIs) as label-free immunoprobes. The performance of the classical MZI is compared with that of a modified structure which incorporates a 3x3 coupler. Characterization of the devices demonstrates a dramatic improvement gained by using the 3x3 coupler. Two main advantages are achieved by the modified device. First, the possibility of referencing the output signal allows the elimination of signal fluctuations due to coupling and light-source instabilities. An increase of the signal-to-noise ratio by a factor of up to 10 is achieved. Secondly, the phase shift between the three outputs allows unambiguous detection with optimum sensitivity. For the detection of the herbicide simazine, the functional properties of the transducer surface are optimized by an appropriate chemical modification. Using this improved device, a simazine immunoassay has been carried out with a test midpoint of 0.3 ppb and a detection limit of approximately 0.1 ppb. The excellent performance, established manufacturing techniques and the potential for simplification and parallelization make the device attractive for further development

    Real-Time and Low-Cost Sensing Technique Based on Photonic Bandgap Structures

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    This paper was published in OPTICS LETTERS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.36.002707. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] A technique for the development of low-cost and high-sensitivity photonic biosensing devices is proposed and experimentally demonstrated. In this technique, a photonic bandgap structure is used as transducer, but its readout is performed by simply using a broadband source, an optical filter, and a power meter, without the need of obtaining the transmission spectrum of the structure; thus, a really low-cost system and real-time results are achieved. Experimental results show that it is possible to detect very low refractive index variations, achieving a detection limit below 2 x 10(-6) refractive index units using this low-cost measuring technique. (C) 2011 Optical Society of America[This work was funded by the Spanish Ministerio de Ciencia e Innovacion (MICINN) under contracts TEC2008-06333, JCI-009-5805, and TEC2008-05490. Support by the Universidad Politecnica de Valencia through program PAID-06-09 and the Conselleria d'Educacio through program GV-2010-031 is acknowledged.GarcĂ­a CastellĂł, J.; Toccafondo, V.; PĂ©rez MillĂĄn, P.; SĂĄnchez Losilla, N.; Cruz, JL.; Andres, MV.; GarcĂ­a-RupĂ©rez, J. (2011). Real-Time and Low-Cost Sensing Technique Based on Photonic Bandgap Structures. Optics Letters. 36(14):2707-2709. https://doi.org/10.1364/OL.36.002707S270727093614Fan, X., White, I. M., Shopova, S. I., Zhu, H., Suter, J. D., & Sun, Y. (2008). Sensitive optical biosensors for unlabeled targets: A review. Analytica Chimica Acta, 620(1-2), 8-26. doi:10.1016/j.aca.2008.05.022Homola, J., Yee, S. S., & Gauglitz, G. (1999). Surface plasmon resonance sensors: review. Sensors and Actuators B: Chemical, 54(1-2), 3-15. doi:10.1016/s0925-4005(98)00321-9Kersey, A. D., Davis, M. A., Patrick, H. J., LeBlanc, M., Koo, K. P., Askins, C. G., 
 Friebele, E. J. (1997). Fiber grating sensors. Journal of Lightwave Technology, 15(8), 1442-1463. doi:10.1109/50.618377De Vos, K., Bartolozzi, I., Schacht, E., Bienstman, P., & Baets, R. (2007). Silicon-on-Insulator microring resonator for sensitive and label-free biosensing. Optics Express, 15(12), 7610. doi:10.1364/oe.15.007610Iqbal, M., Gleeson, M. A., Spaugh, B., Tybor, F., Gunn, W. G., Hochberg, M., 
 Gunn, L. C. (2010). Label-Free Biosensor Arrays Based on Silicon Ring Resonators and High-Speed Optical Scanning Instrumentation. IEEE Journal of Selected Topics in Quantum Electronics, 16(3), 654-661. doi:10.1109/jstqe.2009.2032510Xu, D.-X., Vachon, M., Densmore, A., Ma, R., DelĂąge, A., Janz, S., 
 Schmid, J. H. (2010). Label-free biosensor array based on silicon-on-insulator ring resonators addressed using a WDM approach. Optics Letters, 35(16), 2771. doi:10.1364/ol.35.002771Skivesen, N., TĂȘtu, A., Kristensen, M., Kjems, J., Frandsen, L. H., & Borel, P. I. (2007). Photonic-crystal waveguide biosensor. Optics Express, 15(6), 3169. doi:10.1364/oe.15.003169Lee, M. R., & Fauchet, P. M. (2007). Nanoscale microcavity sensor for single particle detection. Optics Letters, 32(22), 3284. doi:10.1364/ol.32.003284GarcĂ­a-RupĂ©rez, J., Toccafondo, V., Bañuls, M. J., CastellĂł, J. G., Griol, A., Peransi-Llopis, S., & Maquieira, Á. (2010). Label-free antibody detection using band edge fringes in SOI planar photonic crystal waveguides in the slow-light regime. Optics Express, 18(23), 24276. doi:10.1364/oe.18.024276Toccafondo, V., GarcĂ­a-RupĂ©rez, J., Bañuls, M. J., Griol, A., CastellĂł, J. G., Peransi-Llopis, S., & Maquieira, A. (2010). Single-strand DNA detection using a planar photonic-crystal-waveguide-based sensor. Optics Letters, 35(21), 3673. doi:10.1364/ol.35.003673Luff, B. J., Wilson, R., Schiffrin, D. J., Harris, R. D., & Wilkinson, J. S. (1996). Integrated-optical directional coupler biosensor. Optics Letters, 21(8), 618. doi:10.1364/ol.21.000618SepĂșlveda, B., RĂ­o, J. S. del, Moreno, M., Blanco, F. J., Mayora, K., DomĂ­nguez, C., & Lechuga, L. M. (2006). Optical biosensor microsystems based on the integration of highly sensitive Mach–Zehnder interferometer devices. Journal of Optics A: Pure and Applied Optics, 8(7), S561-S566. doi:10.1088/1464-4258/8/7/s41Densmore, A., Vachon, M., Xu, D.-X., Janz, S., Ma, R., Li, Y.-H., 
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    Secondary user relations in emerging mobile computing environments

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    Mobile technologies are enabling access to information in diverse environ.ments, and are exposing a wider group of individuals to said technology. Therefore, this paper proposes that a wider view of user relations than is usually considered in information systems research is required. Specifically, we examine the potential effects of emerging mobile technologies on end-­‐user relations with a focus on the ‘secondary user’, those who are not intended to interact directly with the technology but are intended consumers of the technology’s output. For illustration, we draw on a study of a U.K. regional Fire and Rescue Service and deconstruct mobile technology use at Fire Service incidents. Our findings provide insights, which suggest that, because of the nature of mobile technologies and their context of use, secondary user relations in such emerging mobile environments are important and need further exploration

    Between overt and covert research: concealment and disclosure in an ethnographic study of commercial hospitality

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    This article examines the ways in which problems of concealment emerged in an ethnographic study of a suburban bar and considers how disclosure of the research aims, the recruitment of informants, and elicitation of information was negotiated throughout the fieldwork. The case study demonstrates how the social context and the relationships with specific informants determined overtness or covertness in the research. It is argued that the existing literature on covert research and covert methods provides an inappropriate frame of reference with which to understand concealment in fieldwork. The article illustrates why concealment is sometimes necessary, and often unavoidable, and concludes that the criticisms leveled against covert methods should not stop the fieldworker from engaging in research that involves covertness

    Integrated optical directional coupler sensor for pesticide analysis

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    Integrated optical transducers for the measurement of interactions between biological molecules and the specific detection of chemical and biochemical species are the subject of growing interest. Targeted applications include environmental monitoring, industrial process control and medical diagnostics. Integrated optical devices are capable of delivering the high detection sensitivity achievable through optical techniques in a compact format, and offer the potential for the detection of several analytes simultaneously through the fabrication of multiple transducers on a single chip. Here we describe the use of a new type of integrated optical sensor applied to the detection of low concentrations of the pesticide atrazine in aqueous solution. The transducer is based on a planar waveguide directional coupler structure fabricated by Ag+-Na+ ion-exchange in a low-index glass substrate. This sensor has the advantage of differential outputs, which gives improved signal-to-noise characteristics and offers the potential for the simultaneous measurement of the real and imaginary parts of the refractive indices of bulk or thin-film analytes

    A weighting method to improve habitat association analysis: tested on British carabids

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    Analysis of species’ habitat associations is important for biodiversity conservation and spatial ecology. The original phi coefficient of association is a simple method that gives both positive and negative associations of individual species with habitats. The method originates in assessing the association of plant species with habitats, sampled by quadrats. Using this method for mobile animals creates problems as records often have imprecise locations, and would require either using only records related to a single habitat or arbitrarily choosing a single habitat to assign. We propose and test a new weighted version of the index that retains more records, which improves association estimates and allows assessment of more species. It weights habitats that lie within the area covered by the species record with their certainty level, in our case study, the proportion of the grid cell covered by that habitat. We used carabid beetle data from the National Biodiversity Network atlas and CEH Land Cover Map 2015 across Great Britain to compare the original method with the weighted version. We used presence‐only data, assigning species absences using a threshold based on the number of other species found at a location, and conducted a sensitivity analysis of this threshold. Qualitative descriptions of habitat associations were used as independent validation data. The weighted index allowed the analysis of 52 additional species (19% more) and gave results with as few as 50 records. For the species we could analyse using both indices, the weighted index explained 70% of the qualitative validation data compared to 68% for the original, indicating no accuracy loss. The weighted phi coefficient of association provides an improved method for habitat analysis giving information on preferred and avoided habitats for mobile species that have limited records, and can be used in modelling and analysis that directs conservation policy and practice
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