3,392 research outputs found

    Studying patterns of use of transport modes through data mining - Application to U.S. national household travel survey data set

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    Data collection activities related to travel require large amounts of financial and human resources to be conducted successfully. When available resources are scarce, the information hidden in these data sets needs to be exploited, both to increase their added value and to gain support among decision makers not to discontinue such efforts. This study assessed the use of a data mining technique, association analysis, to understand better the patterns of mode use from the 2009 U.S. National Household Travel Survey. Only variables related to self-reported levels of use of the different transportation means are considered, along with those useful to the socioeconomic characterization of the respondents. Association rules potentially showed a substitution effect between cars and public transportation, in economic terms but such an effect was not observed between public transportation and nonmotorized modes (e.g., bicycling and walking). This effect was a policy-relevant finding, because transit marketing should be targeted to car drivers rather than to bikers or walkers for real improvement in the environmental performance of any transportation system. Given the competitive advantage of private modes extensively discussed in the literature, modal diversion from car to transit is seldom observed in practice. However, after such a factor was controlled, the results suggest that modal diversion should mainly occur from cars to transit rather than from nonmotorized modes to transi

    Light baryon magnetic moments and N -> Delta gamma transition in a Lorentz covariant chiral quark approach

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    We calculate magnetic moments of light baryons and N -> Delta gamma transition characteristics using a manifestly Lorentz covariant chiral quark approach for the study of baryons as bound states of constituent quarks dressed by a cloud of pseudoscalar mesons.Comment: 29 pages, 10 figures, accepted for publication in Phys. Rev.

    Data review for 3LN redfish in preparation for an updated management strategy evaluation

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    Data review for 3LN redfish in preparation for an updated management strategy evaluationVersión del editor

    Simulating Potential Impacts of Future Climate Change on Post-Rainy Season Sorghum Yields in India

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    Given the wide use of the multi-climate model mean (MMM) for impact assessment studies, this work examines the fidelity of Coupled Model Intercomparison Project Phase 5 (CMIP5) in simulating the features of Indian summer monsoons as well as the post-rainy seasons for assessing the possible impacts of climate change on post-rainy season sorghum crop yields across India. The MMM simulations captured the spatial patterns and annual cycles of rainfall and surface air temperatures. However, bias was observed in the precipitation amounts and daily rainfall intensity. The trends in the simulations of MMM for both precipitation and temperatures were less satisfactory than the observed climate means. The Crop Environment Resource Synthesis (CERES)-sorghum model was used to estimate the potential impacts of future climate change on post-rainy season sorghum yield values. On average, post-rainy season sorghum yields are projected to vary betwee

    Chiral Soliton Model vs Pentaquark Structure for \Theta (1540)

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    The exotic baryon Θ+\Theta^+ (1540 MeV)isvisualisedasanexpected(iso)rotationalexcitationintheChiralSolitonModel.ItisalsoarguedasaPentaquarkbaryonstateinaconstituentquarkmodelwithstrongdiquarkcorrelations.Icontrastthetwopointsofview;thesimilaritiesanddifferencesbetweenthetwopictures.Collectiveexcitation,characteristicofChiralSolitonModelpointstowardsmallmixingofrepresentationsinthewakeofSU(3)breaking.Incontrast,ConstituentquarkModelsprefernearidealmixing,similarto is visualised as an expected (iso) rotational excitation in the Chiral Soliton Model. It is also argued as a Pentaquark baryon state in a constituent quark model with strong diquark correlations. I contrast the two points of view; the similarities and differences between the two pictures. Collective excitation, characteristic of Chiral Soliton Model points toward small mixing of representations in the wake of SU(3) breaking. In contrast, Constituent quark Models prefer near ``ideal'' mixing, similar to \omega - \phi$ mixing.Comment: 11 pages, references added, final published versio

    Mapping the spatiotemporal dynamics of calcium signaling in cellular neural networks using optical flow

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    An optical flow gradient algorithm was applied to spontaneously forming net- works of neurons and glia in culture imaged by fluorescence optical microscopy in order to map functional calcium signaling with single pixel resolution. Optical flow estimates the direction and speed of motion of objects in an image between subsequent frames in a recorded digital sequence of images (i.e. a movie). Computed vector field outputs by the algorithm were able to track the spatiotemporal dynamics of calcium signaling pat- terns. We begin by briefly reviewing the mathematics of the optical flow algorithm, and then describe how to solve for the displacement vectors and how to measure their reliability. We then compare computed flow vectors with manually estimated vectors for the progression of a calcium signal recorded from representative astrocyte cultures. Finally, we applied the algorithm to preparations of primary astrocytes and hippocampal neurons and to the rMC-1 Muller glial cell line in order to illustrate the capability of the algorithm for capturing different types of spatiotemporal calcium activity. We discuss the imaging requirements, parameter selection and threshold selection for reliable measurements, and offer perspectives on uses of the vector data.Comment: 23 pages, 5 figures. Peer reviewed accepted version in press in Annals of Biomedical Engineerin

    On Horizons and Plane Waves

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    We investigate the possibility of having an event horizon within several classes of metrics that asymptote to the maximally supersymmetric IIB plane wave. We show that the presence of a null Killing vector (not necessarily covariantly constant) implies an effective separation of the Einstein equations into a standard and a wave component. This feature may be used to generate new supergravity solutions asymptotic to the maximally supersymmetric IIB plane wave, starting from standard seed solutions such as branes or intersecting branes in flat space. We find that in many cases it is possible to preserve the extremal horizon of the seed solution. On the other hand, non-extremal deformations of the plane wave solution result in naked singularities. More generally, we prove a no-go theorem against the existence of horizons for backgrounds with a null Killing vector and which contain at most null matter fields. Further attempts at turning on a nonzero Hawking temperature by introducing additional matter have proven unsuccessful. This suggests that one must remove the null Killing vector in order to obtain a horizon. We provide a perturbative argument indicating that this is in fact possible.Comment: 46 pp, 1 figur

    How artists working in academia view artistic practice as research: Implications for tertiary music education

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    Artistic research output struggles for recognition as ‘legitimate’ research within the highly competitive and often traditional university sector. Often recognition requires the underpinning processes and thinking to be documented in a traditional written format. This article discusses the views of eight arts practitioners working in academia by asking whether or not they view their arts practice as research; and if they do, how it is so. The findings illuminate ways in which artistic practice is understood as research and reveal how the process of analytical and reflective writing impacts artist academics, their artistic and academic identities and their environment. The findings suggest a frame within which to advocate the equivalence of artistic research with traditional scholarly research. They also suggest a rationale for arguing against this, focusing instead (or perhaps as well) on a wider understanding of what constitutes knowledge. This has implications for academics, for students and for universities in recognising the research inherent within arts practice itself, and in recognising the value of practice-led writing in understanding and communicating new knowledge, new methods, and new definitions of research

    Surgery alone for papillary thyroid microcarcinoma is less costly and more effective than long term active surveillance

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    Background: Papillary thyroid microcarcinoma is a subtype of thyroid cancer that may be managed with active surveillance rather than immediate surgery. Active surveillance decreases complication rates and may decrease health care costs. This study aims to analyze complication rates of thyroid surgery, papillary thyroid microcarcinoma recurrence, and survival rates. Additionally, the costs of surgery versus hypothetic active surveillance for papillary thyroid microcarcinoma are compared in an Australian cohort. Methods: Papillary thyroid microcarcinoma patients were included from a prospectively collected surgical cohort of patients treated for papillary thyroid cancer between 1985 and 2017. The primary outcomes were the complications of thyroid surgery, recurrence-free survival, overall survival, and cost of surgical treatment and active surveillance. Results: In a total of 349 patients with papillary microcarcinoma with a median age of 48 years (range, 18–90 years), the permanent operative complications rate was 3.7%. Postoperative radioactive iodine did not decrease recurrence-free survival (P = .3). The total cost of surgical treatment was 10,226Australiandollars,whereashypotheticactivesurveillancewasatayearlycostof10,226 Australian dollars, whereas hypothetic active surveillance was at a yearly cost of 756 Australian dollars. Estimated cost of surgical papillary thyroid microcarcinoma treatment was equivalent to the cost of 16.2 years of active surveillance. Conclusion: Surgery may have a long-term economic advantage for younger Australian patients with papillary thyroid microcarcinoma who are likely to require more than 16.2 years of follow-up in an active surveillance scheme
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