2,768 research outputs found

    A WSN approach to unmanned aerial surveillance of traffic anomalies: Some challenges and potential solutions

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    Stationary CCTV cameras are often used to help monitor car movements and detect any anomalies - e.g., accidents, cars going faster than the allowed speed, driving under the influence of alcohol, etc. The height of the cameras can limit their effectiveness and the types of image processing algorithm which can be used. With advancements in the development of inexpensive aerial flying objects and wireless devices, these two technologies can be coupled to support enhanced surveillance. The flying objects can carry multiple cameras and be sent well above the ground to capture and feed video/image information back to a ground station. In addition, because of the height the objects can achieve, they can capture videos and images which could lend themselves more suitably for the application of a variety of video and image processing algorithms to assist analysts in detecting any anomalies. In this paper, we examine some main challenges of using flying objects for surveillance purposes and propose some potential solutions to these challenges. By doing so, we attempt to provide the basis for developing a framework to build a viable system for improved surveillance based on low-cost equipment. © 2013 IEEE.t.published_or_final_versio

    The behavior of novel hydrophilic composite bone cements in simulated body fluids

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    Composite bone cements were formulated with bioactive glass (MgOOSiO2O3CaO ! P2O5) as the filler and hydrophilic matrix. The matrix was composed of a starch/cellulose acetate blend (SCA) as the solid component and a mixture of methylmethacrylate/acrylic acid (MMA/AA) as the liquid component. The curing parameters, mechanical properties, and bioactive behavior of these composite cements were determined. The addition of up to 30 wt % of glass improved both compressive modulus and yield strength and kept the maximum curing temperature at the same value presented by a typical acrylic-based commercial formulation. The lack of a strongly bonded interface (because no coupling agent was used) had important effects on the swelling and mechanical properties of the novel bone cements. However, bone cements containing AA did not show a bioactive behavior, because of the deleterious effect of this monomer on the calcium phosphate precipitation on the polymeric surfaces. Formulations without AA were prepared with MMA or 2-hydroxyethyl methacrylate (HEMA) as the liquid component. Only these formulations could form an apatite-like layer on their surface. These systems, therefore, are very promising: They are bioactive, hydrophilic, partially degradable, and present interesting mechanical properties. This combination of properties could facilitate the release of bioactive agents from the cement, allow bone ingrowth in the cement, and induce a press-fitting effect, improving the interfaces with both the prosthesis and the bone

    Seagrass can mitigate negative ocean acidification effects on calcifying algae

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    The ultimate effect that ocean acidification (OA) and warming will have on the physiology of calcifying algae is still largely uncertain. Responses depend on the complex interactions between seawater chemistry, global/local stressors and species-specific physiologies. There is a significant gap regarding the effect that metabolic interactions between coexisting species may have on local seawater chemistry and the concurrent effect of OA. Here, we manipulated CO2 and temperature to evaluate the physiological responses of two common photoautotrophs from shallow tropical marine coastal ecosystems in Brazil: the calcifying alga Halimeda cuneata, and the seagrass Halodule wrightii. We tested whether or not seagrass presence can influence the calcification rate of a widespread and abundant species of Halimeda under OA and warming. Our results demonstrate that under elevated CO2, the high photosynthetic rates of H. wrightii contribute to raise H. cuneata calcification more than two-fold and thus we suggest that H. cuneata populations coexisting with H. wrightii may have a higher resilience to OA conditions. This conclusion supports the more general hypothesis that, in coastal and shallow reef environments, the metabolic interactions between calcifying and non-calcifying organisms are instrumental in providing refuge against OA effects and increasing the resilience of the more OA-susceptible species.E.B. would like to thank the Coordenação de Aperfeiçoamento de Pessoas de Nível Superior (CAPES) for Masters funding. Funding for this project came from the Synergism grant (CNPq 407365/2013-3). We extend our thanks to the Brazil-based Projeto Coral Vivo and its sponsor PetroBras Ambiental for providing the Marine Mesocosm structure and experimental assistance.info:eu-repo/semantics/publishedVersio

    A cross-national study on the antecedents of work–life balance from the fit and balance perspective

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    Drawing on the perceived work–family fit and balance perspective, this study investigates demands and resources as antecedents of work–life balance (WLB) across four countries (New Zealand, France, Italy and Spain), so as to provide empirical cross-national evidence. Using structural equation modelling analysis on a sample of 870 full time employees, we found that work demands, hours worked and family demands were negatively related to WLB, while job autonomy and supervisor support were positively related to WLB. We also found evidence that resources (job autonomy and supervisor support) moderated the relationships between demands and work–life balance, with high resources consistently buffering any detrimental influence of demands on WLB. Furthermore, our study identified additional predictors of WLB that were unique to some national contexts. For example, in France and Italy, overtime hours worked were negatively associated with WLB, while parental status was positively associated with WLB. Overall, the implications for theory and practice are discussed.Peer ReviewedPostprint (author's final draft

    Search for the Decays B^0 -> D^{(*)+} D^{(*)-}

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    Using the CLEO-II data set we have searched for the Cabibbo-suppressed decays B^0 -> D^{(*)+} D^{(*)-}. For the decay B^0 -> D^{*+} D^{*-}, we observe one candidate signal event, with an expected background of 0.022 +/- 0.011 events. This yield corresponds to a branching fraction of Br(B^0 -> D^{*+} D^{*-}) = (5.3^{+7.1}_{-3.7}(stat) +/- 1.0(syst)) x 10^{-4} and an upper limit of Br(B^0 -> D^{*+} D^{*-}) D^{*\pm} D^\mp and B^0 -> D^+ D^-, no significant excess of signal above the expected background level is seen, and we calculate the 90% CL upper limits on the branching fractions to be Br(B^0 -> D^{*\pm} D^\mp) D^+ D^-) < 1.2 x 10^{-3}.Comment: 12 page postscript file also available through http://w4.lns.cornell.edu/public/CLNS, submitted to Physical Review Letter

    Measurement of the proton form factor by studying e+eppˉe^{+} e^{-}\rightarrow p\bar{p}

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    Using data samples collected with the BESIII detector at the BEPCII collider, we measure the Born cross section of e+eppˉe^{+}e^{-}\rightarrow p\bar{p} at 12 center-of-mass energies from 2232.4 to 3671.0 MeV. The corresponding effective electromagnetic form factor of the proton is deduced under the assumption that the electric and magnetic form factors are equal (GE=GM)(|G_{E}|= |G_{M}|). In addition, the ratio of electric to magnetic form factors, GE/GM|G_{E}/G_{M}|, and GM|G_{M}| are extracted by fitting the polar angle distribution of the proton for the data samples with larger statistics, namely at s=\sqrt{s}= 2232.4 and 2400.0 MeV and a combined sample at s\sqrt{s} = 3050.0, 3060.0 and 3080.0 MeV, respectively. The measured cross sections are in agreement with recent results from BaBar, improving the overall uncertainty by about 30\%. The GE/GM|G_{E}/G_{M}| ratios are close to unity and consistent with BaBar results in the same q2q^{2} region, which indicates the data are consistent with the assumption that GE=GM|G_{E}|=|G_{M}| within uncertainties.Comment: 13 pages, 24 figure
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