4,767 research outputs found

    Spinning Relativistic Particle in an External Electromagnetic Field

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    The Hamiltonian formulation of the motion of a spinning relativistic particle in an external electromagnetic field is considered. The approach is based on the introduction of new coordinates and their conjugated momenta to describe the spin degrees of freedom together with an appropriate set of constraints in the Dirac formulation. For particles with gyromagnetic ratio g=2g=2, the equations of motion do not predict any deviation from the standard Lorentz force, while for g≠2g \neq 2 an additional force, which corresponds to the magnetic dipole force, is obtained.Comment: Latex file, 11 page

    New trends on urban goods movement: Modelling and simulation of e-commerce distribution

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    In this paper, a modelling framework to complete the recent scientific works on urban goods modelling is proposed. More precisely, we introduce a substitution procedure that estimates the number of trips and the corresponding travelled distances for shopping drive, home delivery and reception points' strategies. Moreover, an appraisal of scenarios is proposed in order to study how these three new forms of proximity delivery services impact on the overall urban goods movement distribution. Starting from four extreme situations, we introduce more realistic scenarios in order to find a suitable combination of delivery strategies. All the scenarios are simulated using the proposed framework, and the main traffic issues related to e-commerce distribution channel are discussed. The best realistic combination promotes the joint usage of home deliveries and proximity reception points and allows a reduction of about 13% of the road occupancy rates in urban areas.urban goods movement, modelling, shopping trips, e-commerce

    Infantile hemangioma presenting as colocolic intussusception in an infant case report with review of pathologic lead points

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    Infantile hemangioma (IH) is one of the most common vascular anomalies of early childhood and is usually recognized in the first few weeks to months of life as a solitary cutaneous lesion. This report documents our experience with a GLUT-1 positive IH presenting as the pathologic lead point in a colocolic intussusception in a 10-week-old infant who had no skin lesions. Literature suggests approximately 2% of all children presenting with an intussusception require surgical intervention; however, an IH as the pathologic lead point is unique

    End consumer goods movement generation in French medium urban areas

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    End-consumer movements, defined as the movements made by the consumer transporting the purchased goods, are identified with shopping trips. Whereas the logistics movements (freight distribution and urban part of the supply chain) are well studied in city logistics and urban planning, the end-consumer movements are usually related only to people movements. This paper presents a new modelling approach to characterise the shopping trips within a city logistics point of view, in order to connect these movements with those belonging to urban freight distribution in the supply chain. We present a trip generation model built from the data of recent household trip surveys, more precisely for the urban community of Lyon (France). We present the main results produced by the various simulations in a short-term planning horizon.Urban freight; trip generation modelling; simulation; urban policy; decision-making support

    A Phenomenological Study of Adult Patients with Auto-Immune Disease and Their Exposure to Adverse Childhood Experiences

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    This qualitative phenomenological study explored and described the shared experiences of individuals impacted by an autoimmune disease and their exposure to adverse childhood experiences. The theory guiding this study was Vygotsky’s social constructivist theory, utilizing Kaiser Permanente’s Adverse Childhood Experience study as a guide to create awareness amongst physicians and mental health professionals, leading them to a more holistic approach when treating patients affected by an autoimmune disease. This was a qualitative study using Husserl’s transcendental phenomenology (TPh). The data collection methods used in the study included questionnaires, individual interviews, and document analysis. These forms of data were analyzed through member-checking, triangulation of data, and peer debriefing

    Survival and Nesting Ecology of Scaled Quail in the Trans-Pecos, Texas

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    Scaled quail (Callipepla squamata) are one of the most ecologically and economically important wildlife species in the Trans-Pecos, because they are the primary upland game bird in the Chihuahuan Desert. Using radiotelemetry, we evaluated survival (Kaplan–Meier) and nesting success of quail on 3 study sites in the Trans-Pecos, Texas: one (Santiago Mountain Ranch, central Brewster Co.) was supplemented with milo (Sorghum bicolor) year-round, the second (Lado Ranch, south Culberson Co.) never used supplements, and the third (Apache Ranch, central Culberson Co.) was supplemented with quail blocks. We trapped and radiocollared 164 female quail collectively across all study sites, and followed them for 2 years (May–Sep 2012–2013). There were no survival differences between years within study sites (P = 0.985), so we grouped data across years and compared survival between study sites. Apache Ranch had the lowest survival (55%) compared with the Santiago Mountain Ranch (76.3%) and Lado Ranch (75%). We found 47 nests across the reproductive seasons for 2012 and 2013. On average, scaled quail had high nesting success (72.6%), eggs per nest (11.6), and hatchability (91.25%). Nesting occurred from May to September with peak nesting in June and July. Timing and quantity of rain, combined with range conditions seemed to have the greatest effect on nesting performance

    Dugbe virus replication in nymph and adult Amblyomma variegatum

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    Des spécimens d'adultes et de nymphes de tiques $Amblyomma variegatum# colonisées au laboratoire ont été infectés expérimentalement avec deux préparations de virus Dugbe. La phase d'éclipse du virus chez la tique augmente avec la dilution de la suspension virale. La replication du virus est supérieure chez les adultes par rapport à celle observée chez les nymphes. Le titre viral après le 9e jour post-inoculation est sensiblement le même quel que soit le titre de l'inoculum initial toutefois, un inoculum de titre élevé entraînerait un phénomène d'interférence, diminuant d'autant le pouvoir amplificateur de la tique sur le virus (Résumé d'auteur

    Fermi surface renormalization in Hubbard ladders

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    We derive the one-loop renormalization equations for the shift in the Fermi-wavevectors for one-dimensional interacting models with four Fermi-points (two left and two right movers) and two Fermi velocities v_1 and v_2. We find the shift to be proportional to (v_1-v_2)U^2, where U is the Hubbard-U. Our results apply to the Hubbard ladder and to the t_1-t_2 Hubbard model. The Fermi-sea with fewer particles tends to empty. The stability of a saddle point due to shifts of the Fermi-energy and the shift of the Fermi-wavevector at the Mott-Hubbard transition are discussed.Comment: 5 pages, 4 Postscript figure
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