6 research outputs found

    Incoherent Eta Photoproduction from the Deuteron near Threshold

    Get PDF
    Very recent data for the reaction gamma+d ->eta np, namely total cross sections, angular and momentum spectra, are analyzed within a model that includes contributions from the impulse approximation and next order corrections due to the np and eta-N interactions in the final state. Comparison between the calculations and the new data indicate sizable contributions from the np and eta-N final state interactions. Some systematic discrepancies between the calculations and the data are also found

    Coherent States of the SU(N) groups

    Full text link
    Coherent states (CS)(CS) of the SU(N)SU(N) groups are constructed explicitly and their properties are investigated. They represent a nontrivial generalization of the spining CSCS of the SU(2)SU(2) group. The CSCS are parametrized by the points of the coset space, which is, in that particular case, the projective space CPN1CP^{N-1} and plays the role of the phase space of a corresponding classical mechanics. The CSCS possess of a minimum uncertainty, they minimize an invariant dispersion of the quadratic Casimir operator. The classical limit is ivestigated in terms of symbols of operators. The role of the Planck constant playes h=P1h=P^{-1}, where PP is the signature of the representation. The classical limit of the so called star commutator generates the Poisson bracket in the CPN1CP^{N-1} phase space. The logarithm of the modulus of the CSCS overlapping, being interpreted as a symmetric in the space, gives the Fubini-Study metric in CPN1CP^{N-1}. The CSCS constructed are useful for the quasi-classical analysis of the quantum equations of the SU(N)SU(N) gauge symmetric theories.Comment: 19pg, IFUSP/P-974 March/199

    NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

    Get PDF
    Xenarthrans – anteaters, sloths, and armadillos – have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset

    Do corticosteroids have different effects in preterm or small babies?

    No full text
    Logical management of hypertension and its neurological complications requires understanding of the mechanisms determining pulsatile cerebral blood flow, their disturbance in disease, and their amelioration with therapy. To date, emphasis has been directed to compliance of arterial and arteriolar vessels within the skull. This approach differs with approaches addressing pulsatile function in vascular beds elsewhere. In 10 patients with normal pressure hydrocephalus (NPH), the relationships between central aortic pressure (AP) and intracranial pressure (ICP) waves were studied prior to establishment of a required cerebrospinal fluid shunt to the pleural cavity. Pressures were measured from within the radial artery and cerebral ventricle with matched, fluid-filled, high-frequency manometers. Radial pressure waves were converted to aortic waves using SphygmoCor®. Simultaneously recorded AP and ICP waves were ensemble-averaged and compared in the time and frequency domains. Basic characteristics of patients were: diagnosed NPH with typical clinical features; age 76±4 years, 6 males, systolic 149±19 mmHg, diastolic 62±13 mmHg, mean AP 90±8 mmHg, mean ICP 0.5±3.7 mmHg, pulse AP 60±13 mmHg, pulse ICP 6±2 mmHg. ICP and AP pressure waves were similar and ratio of ICP/ AP amplitude was 0.08±0.01. Similarity in the time domain was confirmed by similarity of ICP/ AP of the first 3 harmonics (which contained 98% of waveform energy) and mean phase delay close to or not significantly different from zero. Close correspondence of ICP and AP pressure waveforms in both time and frequency domains indicates ICP pulsations are due to pulsations of pressure in cerebral arteries without any appreciable effect of venous pressure. Since aortic pressure pulsations are markedly effected by wave reflection from the lower body, one must consider effects of drugs on systemic wave reflection when attempting to reduce fluctuations of ICP.1 page(s

    NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics

    No full text
    Mammalian carnivores are considered a key group in maintaining ecological health and can indicate potential ecological integrity in landscapes where they occur. Carnivores also hold high conservation value and their habitat requirements can guide management and conservation plans. The order Carnivora has 84 species from 8 families in the Neotropical region: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; and Ursidae. Herein, we include published and unpublished data on native terrestrial Neotropical carnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTROPICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from 35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data were obtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organizations, and private consultants. Data were collected using several methods including camera trapping, museum collections, roadkill, line transect, and opportunistic records. Literature (peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated in this compilation. Most of the data set consists of detection data entries (n = 79,343; 79.7%) but also includes non-detection data (n = 20,262; 20.3%). Of those, 43.3% also include count data (n = 43,151). The information available in NEOTROPICAL CARNIVORES will contribute to macroecological, ecological, and conservation questions in multiple spatio-temporal perspectives. As carnivores play key roles in trophic interactions, a better understanding of their distribution and habitat requirements are essential to establish conservation management plans and safeguard the future ecological health of Neotropical ecosystems. Our data paper, combined with other large-scale data sets, has great potential to clarify species distribution and related ecological processes within the Neotropics. There are no copyright restrictions and no restriction for using data from this data paper, as long as the data paper is cited as the source of the information used. We also request that users inform us of how they intend to use the data

    NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

    No full text
    Xenarthrans—anteaters, sloths, and armadillos—have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, 10 anteaters, and 6 sloths. Our data set includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the southern United States, Mexico, and Caribbean countries at the northern portion of the Neotropics, to the austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n = 5,941), and Cyclopes sp. have the fewest (n = 240). The armadillo species with the most data is Dasypus novemcinctus (n = 11,588), and the fewest data are recorded for Calyptophractus retusus (n = 33). With regard to sloth species, Bradypus variegatus has the most records (n = 962), and Bradypus pygmaeus has the fewest (n = 12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other data sets of Neotropical Series that will become available very soon (i.e., Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans data set. Please cite this data paper when using its data in publications. We also request that researchers and teachers inform us of how they are using these data
    corecore