4,049 research outputs found

    Air Taxi Skyport Location Problem for Airport Access

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    Witnessing the rapid progress and accelerated commercialization made in recent years for the introduction of air taxi services in near future across metropolitan cities, our research focuses on one of the most important consideration for such services, i.e., infrastructure planning (also known as skyports). We consider design of skyport locations for air taxis accessing airports, where we present the skyport location problem as a modified single-allocation p-hub median location problem integrating choice-constrained user mode choice behavior into the decision process. Our approach focuses on two alternative objectives i.e., maximizing air taxi ridership and maximizing air taxi revenue. The proposed models in the study incorporate trade-offs between trip length and trip cost based on mode choice behavior of travelers to determine optimal choices of skyports in an urban city. We examine the sensitivity of skyport locations based on two objectives, three air taxi pricing strategies, and varying transfer times at skyports. A case study of New York City is conducted considering a network of 149 taxi zones and 3 airports with over 20 million for-hire-vehicles trip data to the airports to discuss insights around the choice of skyport locations in the city, and demand allocation to different skyports under various parameter settings. Results suggest that a minimum of 9 skyports located between Manhattan, Queens and Brooklyn can adequately accommodate the airport access travel needs and are sufficiently stable against transfer time increases. Findings from this study can help air taxi providers strategize infrastructure design options and investment decisions based on skyport location choices.Comment: 25 page

    Studies on the inheritance of leaf blast resistance in rice

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    Studies on the inheritance of leaf blast resistance in seven differential varieties of rice tested against two Indian isolates of the international races IA-11 add ID-1 of Pyricularia oryzae Cav. under standardized experimental conditions revealed the presence of three dominant genes, one each in Zenith. Tetep and Ginga conferring resistance to IA-11 and two, one each in Zenith and Tetep, to the race ID-1. The genes of Zenith were independent of those of Tetep. C.l. 5309 possessed inhibitory genes inhibiting the resistance of Zenith but not of Telep. Mode of segregation of resistance o Norin 20 to the race IA-11 was found to be anamolous. Studies on the crosses among susecptible varieties showed the existence of dominant genes conferring susceptibility, two each in P.I. 180061 and Yakeiko. This is a new feature of the present studies and its utility in evolving homozygous recessive resistant varieties have been pointed out

    Dynamic patterns of expertise: The case of orthopedic medical diagnosis

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    The aim of this study was to analyze dynamic patterns for scanning femoroacetabular impingement (FAI) radiographs in orthopedics, in order to better understand the nature of expertise in radiography. Seven orthopedics residents with at least two years of expertise and seven board-certified orthopedists participated in the study. The participants were asked to diagnose 15 anteroposterior (AP) pelvis radiographs of 15 surgical patients, diagnosed with FAI syndrome. Eye tracking data were recorded using the SMI desk-mounted tracker and were analyzed using advanced measures and methodologies, mainly recurrence quantification analysis. The expert orthopedists presented a less predictable pattern of scanning the radiographs although there was no difference between experts and non-experts in the deterministic nature of their scan path. In addition, the experts presented a higher percentage of correct areas of focus and more quickly made their first comparison between symmetric regions of the pelvis. We contribute to the understanding of experts' process of diagnosis by showing that experts are qualitatively different from residents in their scanning patterns. The dynamic pattern of scanning that characterizes the experts was found to have a more complex and less predictable signature, meaning that experts' scanning is simultaneously both structured (i.e. deterministic) and unpredictable

    Racism and anti-racism in Europe: a critical analysis of concepts and frameworks

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    The targets and expressions of racism vary across Europe. This article discusses the relevance of different descriptions and analyses of racism despite the different terms used in different countries such as ‘ethnic minority’, ‘foreigner’ or ‘black’ and different interpretations of which differences matter. It shows the significance of a cross-national European perspective on racism. There are important convergences across European countries in the discourses and practices of racism, particularly the distinction between ‘useful’ and ‘abusive’ migrants. A cross-European perspective can be an important inspiration for anti-racist struggles

    Efficient presentation of both cytosolic and endogenous transmembrane protein antigens on MHC class II is dependent on cytoplasmic proteolysis

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    Peptides from extracellular proteins presented on MHC class II are mostly generated and loaded in endolysosomal compartments, but the major pathways responsible for loading peptides from APC-endogenous sources on MHC class II are as yet unclear. In this study, we show that MHC class II molecules present peptides from proteins such as OVA or conalbumin introduced into the cytoplasm by hyperosmotic pinosome lysis, with efficiencies comparable to their presentation via extracellular fluid-phase endocytosis. This cytosolic presentation pathway is sensitive to proteasomal inhibitors, whereas the presentation of exogenous Ags taken up by endocytosis is not. Inhibitors of nonproteasomal cytosolic proteases can also inhibit MHC class II-restricted presentation of cytosolically delivered protein, without inhibiting MHC class I-restricted presentation from the same protein. Cytosolic processing of a soluble fusion protein containing the peptide epitope I-Eα 52-68 yields an epitope that is similar to the one generated during constitutive presentation of I-Eα as an endogenous transmembrane protein, but is subtly different from the one generated in the exogenous pathway. Constitutive MHC class II-mediated presentation of the endogenous transmembrane protein I-Eα is also specifically inhibited over time by inhibitors of cytosolic proteolysis. Thus, Ag processing in the cytoplasm appears to be essential for the efficient presentation of endogenous proteins, even transmembrane ones, on MHC class II, and the proteolytic pathways involved may differ from those used for MHC class I-mediated presentation

    Nuclear matrix elements calculation for 0νββ0\nu\beta\beta decay of 124^{124}Sn using nonclosure approach in nuclear shell model

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    In this study, we calculate the nuclear matrix elements (NMEs) for the light neutrino-exchange mechanism of neutrinoless double beta 0νββ0\nu\beta\beta) decay of 124^{124}Sn within the framework of the interacting nuclear shell model using the effective shell model Hamiltonian GCN5082. A novel method based on a nonclosure approach is employed, wherein for the intermediate nucleus 124^{124}Sb, effects of energy of 100 states for each JkπJ_{k}^{\pi}=0+0^{+} to 11+11^{+} and 22^{-} to 99^{-} (ΔJk\Delta J_{k}=1) are explicitly included in the NMEs calculation. Other common effects such as the finite size of nucleons, higher-order effects of nucleon currents, and short-range correlations (SRC) of nucleons are also taken into account. The extracted optimal closure energy is 2.9 MeV for a total NME of 124^{124}Sn 0νββ0\nu\beta\beta decay, which is independent of different forms of SRC parametrizations. A comparison of NMEs and half-lives with some of the recent calculations is presented. Further, to gain a comprehensive understanding of the role of nuclear structure on the 0νββ0\nu\beta\beta decay, the dependence of NMEs on spin-parity of the intermediate states, coupled spin-parity of neutrons and protons, and the number of intermediate states, is explored. It is observed that the inclusion of the effects of excitation energies of the intermediate nucleus yields more reliable NMEs. The present findings provide valuable insights for experimental investigations of 0νββ0\nu\beta\beta decay of 124^{124}Sn in India and elsewhere.Comment: 12 pages, 6 figures, submitted in the journal Physical Review C. arXiv admin note: text overlap with arXiv:2308.0821

    Direct extreme UV-lithographic conversion of metal xanthates into nanostructured metal sulfide layers for hybrid photovoltaics

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    We present a versatile strategy toward the preparation of nanostructured metal sulfide layers, which exploits the photosensitivity of metal xanthates as a powerful tool for lithographic structuring. Using extreme ultraviolet interference lithography (EUV-IL), we successfully realized well-defined column and comb nanostructures. This approach provides new pathways to fabricate highly ordered structured metal sulfide layers with periodicities far below 100 nm for potential application in hybrid solar cells. © 2013 The Royal Society of Chemistry
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