2,261 research outputs found

    An improved method for the identification of galaxy systems: Measuring the gravitational redshift by Dark Matter Haloes

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    We introduce a new method for the identification of galaxy systems in redshift surveys based on the halo model. This method is a modified version of the K-means identification algorithm developed by Yang et al (2005). We have calibrated and tested our algorithms using mock catalogs generated using the Millennium simulations (Springel et al. 2005) and applied them to the NYU-DR7 galaxy catalog (based on the SDSS datasets). Using this local sample of groups and clusters of galaxies we have measured the effect of gravitational redshift produced by their host dark matter haloes. Our results shows radial velocity decrements consistent with general relativity predictions and previous measurements by Wojtak et al (2011) in clusters of galaxies.Comment: Accepted for Publication in MNRAS Letters, 2 figures. arXiv admin note: text overlap with arXiv:astro-ph/0405234, arXiv:astro-ph/0406593 by other author

    Electric vehicle fleet management using ant colony optimisation

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    This research is focused on implementation of the ant colony optimisation (ACO) technique to solve an advanced version of the vehicle routing problem (VRP), called the fleet management system (FMS). An optimum solution of VRP can bring benefits for the fleet operators as well as contributing to the environment. Nowadays, particular considerations and modifications are needed to be applied in the existing FMS algorithms in response to the rapid growth of electric vehicles (EVs). For example, current FMS algorithms do not consider the limited range of EVs, their charging time or battery degradation. In this study, a new ACO-based FMS algorithm is developed for a fleet of EVs. A simulation platform is built in order to evaluate performance of the proposed FMS algorithm under different simulation case-studies. The simulation results are validated against a well-established method in the literature called nearest-neighbour technique. In each case-study, the overall mileage of the fleet is considered as an index to measure the performance of the FMS algorithm

    Waves, analytical signals, and some postulates of quantum theory

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    In this paper we apply the formalism of the analytical signal theory to the Schrödinger wavefunction. Making use exclusively of the wave-particle duality and the rinciple of relativistic covariance, we actually derive the form of the quantum energy and momentum operators for a single nonrelativistic particle. Without using any more quantum postulates, and employing the formalism of the characteristic function, we also derive the quantum-mechanical prescription for the measurement probability in such cases

    Reproductive inequalities in the acanthocephalan Corynosoma cetaceum: looking beyond "crowding" effects

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    Background: At present, much research effort has been devoted to investigate overall (average) responses of parasite populations to specific factors, e.g., density-dependence in fecundity or mortality. However, studies on parasite populations usually pay little attention to individual variation (inequality) in reproductive success. A previous study on the acanthocephalan Corynosoma cetaceum in franciscana dolphins, Pontoporia blainvillei, revealed no overall intensity-dependent, or microhabitat effects, on mass and fecundity of worms. In this study, we investigated whether the same factors could influence mass inequalities for this species of acanthocephalan.Methods: A total of 10,138 specimens of C. cetaceum were collected from 10 franciscana dolphins accidentally caught in Buenos Aires Province between 1988-1990. To investigate mass inequalities, all the specimens were sexed, and females were classified according to their developmental stage and weighted. Additionally, the relationship between biomass and fecundity (estimated as the number of acanthors) was investigated for some females. Inequalities in fecundity and biomass were assessed using standard methods, i.e. the Lorenz curve and the Gini coefficient (G).Results: We found a modest, but highly significant linear relationship between mass and fecundity. The G was very low (0.314) compared with that from other helminth species. G values were significantly lower in gravid females, which presumably exhibit a slow rate of growth. Also, G values significantly increased with total intensity, but only for gravid females, and the effect was more predictable considering only the number of gravid females.Conclusions: Apparently, competition between reproducing females increases inequality without producing crowding effects. Although the mechanism whereby this occurs is unclear, gravid females, at higher intensities, expanded their distribution and occupied gut chambers with contrasting environmental conditions, which might result in greater variability in body size. The observed inequalities are not expected to strongly influence the population genetics of C. cetaceum, but they reveal subtle individual effects beyond an overall population impact.Fil: Aznar Avendaño, Francisco Javier. Universidad de Valencia; EspañaFil: Hernández Orts, Jesús Servando. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; ArgentinaFil: Vélez Rubio, Gabriela Manuela. Universidad de Valencia; España. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de la República; UruguayFil: Fernández, Luis M.. Ceiba Foundation for Tropical Conservation; Estados UnidosFil: Muriel, Nadia T.. No especifíca;Fil: Raga, Juan Antonio. Universidad de Valencia; Españ

    Structure-function mapping of a heptameric module in the nuclear pore complex.

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    The nuclear pore complex (NPC) is a multiprotein assembly that serves as the sole mediator of nucleocytoplasmic exchange in eukaryotic cells. In this paper, we use an integrative approach to determine the structure of an essential component of the yeast NPC, the ~600-kD heptameric Nup84 complex, to a precision of ~1.5 nm. The configuration of the subunit structures was determined by satisfaction of spatial restraints derived from a diverse set of negative-stain electron microscopy and protein domain-mapping data. Phenotypic data were mapped onto the complex, allowing us to identify regions that stabilize the NPC's interaction with the nuclear envelope membrane and connect the complex to the rest of the NPC. Our data allow us to suggest how the Nup84 complex is assembled into the NPC and propose a scenario for the evolution of the Nup84 complex through a series of gene duplication and loss events. This work demonstrates that integrative approaches based on low-resolution data of sufficient quality can generate functionally informative structures at intermediate resolution

    Food ProteineInduced Enterocolitis Syndrome in Adulthood: Clinical Characteristics, Prognosis, and Risk Factors

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    Background: Food protein-induced enterocolitis syndrome (FPIES) in adults is being increasingly recognized; however, little is known about its characteristics.Objective: To describe the clinical characteristics, prognosis, and associated factors in adult FPIES.Methods: A 10-year prospective study was conducted in the Allergy Section of Alicante General Hospital in adults diagnosed with FPIES. Detailed interviews with patients and oral food challenges (OFCs) were performed to confirm diagnosis or evaluate for tolerance. Comorbidities and possible risk factors were analyzed retrospectively through electronic medical records to assess their association with the disease.Results: One hundred and seven adults with FPIES (93.5% female) were followed for a median of 6.2 years. Abdominal pain was the most common manifestation (96.3%), followed by diarrhea (72%) and vomiting (60.7%). Seafood (59.8%), egg (14%), and milk (10.3%) were the most common triggers, whereas 43.9% reacted to more than 1 food group. We performed 49 OFCs: 9 to confirm diagnosis and 40 to evaluate for tolerance. After a median 3.5 years, 16.8% achieved tolerance. Resolution was correlated inversely with duration of the disease (P = .04) and seafood (P = .023) but not with age of onset. The prevalence of gastrointestinal pathologies such as irritable bowel syndrome (IBS), eosinophilic esophagitis, inflammatory bowel disease, and celiac disease was higher than in the general population. A higher number of FPIES triggers were correlated with also having a diagnosis of IBS (P = .02).Conclusions: Although adult FPIES normally persists, some patients achieve tolerance. Adults with FPIES have a relatively high prevalence of gastrointestinal pathologies. The predominance of women may be related to hormonal factors. The clinical differences with pediatric FPIES warrant a revision of diagnostic criteria in adults

    Food ProteineInduced Enterocolitis Syndrome in Adulthood: Clinical Characteristics, Prognosis, and Risk Factors

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    Food proteineinduced enterocolitis syndrome (FPIES) in adults is being increasingly recognized; however, little is known about its characteristics. OBJECTIVE: To describe the clinical characteristics, prognosis, and associated factors in adult FPIES. METHODS: A 10-year prospective study was conducted in the Allergy Section of Alicante General Hospital in adults diagnosed with FPIES. Detailed interviews with patients and oral food challenges (OFCs) were performed to confirm diagnosis or evaluate for tolerance. Comorbidities and possible risk factors were analyzed retrospectively through electronic medical records to assess their association with the disease. RESULTS: One hundred and seven adults with FPIES (93.5% female) were followed for a median of 6.2 years. Abdominal pain was the most common manifestation (96.3%), followed by diarrhea (72%) and vomiting (60.7%). Seafood (59.8%), egg (14%), and milk (10.3%) were the most common triggers, whereas 43.9% reacted to more than 1 food group. We performed 49 OFCs: 9 to confirm diagnosis and 40 to evaluate for tolerance. After a median 3.5 years, 16.8% achieved tolerance. Resolution was correlated inversely with duration of the disease (P[.04) and seafood (P[.023) but not with age of onset. The prevalence of gastrointestinal pathologies such as irritable bowel syndrome (IBS), eosinophilic esophagitis, inflammatory bowel disease, and celiac disease was higher than in the general population. A higher number of FPIES triggers were correlated with also having a diagnosis of IBS (P [ .02).CONCLUSIONS: Although adult FPIES normally persists, some patients achieve tolerance. Adults with FPIES have a relatively high prevalence of gastrointestinal pathologies. The predominance of women may be related to hormonal factors. The clinical differences with pediatric FPIES warrant a revision of diagnostic criteria in adults
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