13,034 research outputs found
Multiscale probability mapping: groups, clusters and an algorithmic search for filaments in SDSS
We have developed a multiscale structure identification algorithm for the
detection of overdensities in galaxy data that identifies structures having
radii within a user-defined range. Our "multiscale probability mapping"
technique combines density estimation with a shape statistic to identify local
peaks in the density field. This technique takes advantage of a user-defined
range of scale sizes, which are used in constructing a coarse-grained map of
the underlying fine-grained galaxy distribution, from which overdense
structures are then identified. In this study we have compiled a catalogue of
groups and clusters at 0.025 < z < 0.24 based on the Sloan Digital Sky Survey,
Data Release 7, quantifying their significance and comparing with other
catalogues. Most measured velocity dispersions for these structures lie between
50 and 400 km/s. A clear trend of increasing velocity dispersion with radius
from 0.2 to 1 Mpc/h is detected, confirming the lack of a sharp division
between groups and clusters. A method for quantifying elongation is also
developed to measure the elongation of group and cluster environments. By using
our group and cluster catalogue as a coarse-grained representation of the
galaxy distribution for structure sizes of <~ 1 Mpc/h, we identify 53 filaments
(from an algorithmically-derived set of 100 candidates) as elongated unions of
groups and clusters at 0.025 < z < 0.13. These filaments have morphologies that
are consistent with previous samples studied.Comment: 22 pages, 14 figures and 6 tables. Accepted for publication in MNRAS.
Data products, three-dimensional visualisations and further information about
MSPM can be found at http://www.physics.usyd.edu.au/sifa/Main/MSPM/ . v2
contains two additional references. v3 has a slightly altered title and
updated reference
Retrograde transport pathways utilised by viruses and protein toxins
A model has been presented for retrograde transport of certain toxins and viruses from the cell surface to the ER that suggests an obligatory interaction with a glycolipid receptor at the cell surface. Here we review studies on the ER trafficking cholera toxin, Shiga and Shiga-like toxins, Pseudomonas exotoxin A and ricin, and compare the retrograde routes followed by these protein toxins to those of the ER trafficking SV40 and polyoma viruses. We conclude that there is in fact no obligatory requirement for a glycolipid receptor, nor even with a protein receptor in a lipid-rich environment. Emerging data suggests instead that there is no common pathway utilised for retrograde transport by all of these pathogens, the choice of route being determined by the particular receptor utilised
Communicating by employee reports: a survey of employee attitudes
Over the past few years there has been a growing interest in the general disclosure of a companys financial information to all of its employees. 'In rnany cases this has Inanifested itself in the form of a firm issuing \Vhat is known as an employee repon to ·its staff. Typicall). an employee report summarises the factual information contained in the statutO'I)' annual report but does so in a simplified fonn \\1hich is easier for non-accountants to understand. In addition. the employee r~eport often contains non-financial information \Vhi·ch does not appear in the annual accounts nor in any other company publication. While un·ion negotiators may have access to dctail·ed accounting infonnation. the general rank and file etnr.Joyecs probably get most of their financial kno\vledge about 'the ent~erprise they 'NOrk for via an em ployee report. A recent study by Firth and Smith (1984) found that nearly one-half of publicly listed Nevl Zealand companies currently produce some form of e1nployee r·eport. Additionally. many of the New Zealand subsidiaries of 'larger overseas firms also issue such reports. ln spite of the large number of finns involved. there has not. until no\v. been any fonnal a sessment of employee attitudes regarding such reports. The purpose oft he paper is to address this need by reporting the results of a questionnaire-based survey of employee opinion
The Navigation Surface: A New Database Approach to Creating Multiple Products from High-density Surveys
High-resolution bathymetric surveys are revolutionising hydrographic surveying. ln addition to safety-of-navigation , there are a host of other uses for high-resolution bathymetry, including habitat mapping, hydrologic modelling, marine archaeology, and marine environmental protection. However, at present, there is no suitable method that can be used to produce multiple products that meet the needs of both navigation customers and other users . A research project conducted at the University of New Hampshire developed a model of the seafloor that is optimised for safety-of-navigation . This new technique bypasses the rather subjective, \u27selected soundings\u27 approach. Instead, a statistical model is created directly from the cleaned and processed data. The model - called a \u27navigation surface\u27 - consists of a high-resolution bathymetric grid with an uncertainty value assigned to each node on the grid. The model is then optimised to preserve the least depths over significant features . For each node an uncertainty value is computed which becomes an integral part of the model. The distribution of the points around the mean is combined with the predicted uncertainty of each measurement to form an overall uncertainty model. For low-density single-beam and lead-line surveys, the area between measurements is modelled based on a triangular irregular network (TIN). The uncertainty model then incorporates the distance from the measurement, as well as the uncertainty of the measurement itse lf
UK marginal cost curves for the agriculture, forestry, land-use and land-use change sector out to 2022 and to provide scenario analysis for possible abatement options out to 2050 – RMP4950.
Dietary patterns obtained through principal components analysis: The effect of input variable quantification
Principal components analysis (PCA) is a popular method for deriving dietary patterns. A number of decisions must be made throughout the analytic process, including how to quantify the input variables of the PCA. The present study aims to compare the effect of using different input variables on the patterns extracted using PCA on 3-d diet diary data collected from 7473 children, aged 10 years, in the Avon Longitudinal Study of Parents and Children. Four options were examined: weight consumed of each food group (g/d), energy-adjusted weight, percentage contribution to energy of each food group and binary intake (consumed/not consumed). Four separate PCA were performed, one for each intake measurement. Three or four dietary patterns were obtained from each analysis, with at least one component that described 'more healthy' and 'less healthy' diets and one component that described a diet with high consumption of meat, potatoes and vegetables. There were no obvious differences between the patterns derived using percentage energy as a measurement and adjusting weight for total energy intake, compared to those derived using gram weights. Using binary input variables yielded a component that loaded positively on reduced fat and reduced sugar foods. The present results suggest that food intakes quantified by gram weights or as binary variables both resulted in meaningful dietary patterns and each method has distinct advantages: weight takes into account the amount of each food consumed and binary intake appears to describe general food preferences, which are potentially easier to modify and useful in public health settings. © 2012 The Authors
Chandra Snapshot Observations of Low-Luminosity AGNs with a Compact Radio Source
The results of Chandra snapshot observations of 11 LINERs (Low-Ionization
Nuclear Emission-line Regions), three low-luminosity Seyfert galaxies, and one
HII-LINER transition object are presented. Our sample consists of all the
objects with a flat or inverted spectrum compact radio core in the VLA survey
of 48 low-luminosity AGNs (LLAGNs) by Nagar et al. (2000). An X-ray nucleus is
detected in all galaxies except one and their X-ray luminosities are in the
range 5x10^38 to 8x10^41 erg/s. The X-ray spectra are generally steeper than
expected from thermal bremsstrahlung emission from an advection-dominated
accretion flow (ADAF). The X-ray to Halpha luminosity ratios for 11 out of 14
objects are in good agreement with the value characteristic of LLAGNs and more
luminous AGNs, and indicate that their optical emission lines are predominantly
powered by a LLAGN. For three objects, this ratio is less than expected.
Comparing with properties in other wavelengths, we find that these three
galaxies are most likely to be heavily obscured AGN. We use the ratio RX = \nu
L\nu (5 GHz)/LX, where LX is the luminosity in the 2-10 keV band, as a measure
of radio loudness. In contrast to the usual definition of radio loudness (RO =
L\nu(5 GHz)/L\nu(B)), RX can be used for heavily obscured (NH >~ 10^23 cm^-2,
AV>50 mag) nuclei. Further, with the high spatial resolution of Chandra, the
nuclear X-ray emission of LLAGNs is often easier to measure than the nuclear
optical emission. We investigate the values of RX for LLAGNs, luminous Seyfert
galaxies, quasars and radio galaxies and confirm the suggestion that a large
fraction of LLAGNs are radio loud.Comment: 15 pages, accepted for publication in Ap
Soybean Marketing Methods and Characteristics of Arkansas Grain Handlers
Arkansas producers should acquaint themselves with all marketing methods available to them. Of particular importance is the pervasiveness of price risk within the current economic climate. This bulletin provides insights into the current structure of the grain marketing industry, soybean handler characteristics, and the availability and use of marketing alternatives in Arkansas. Arkansas soybean handlers were surveyed in 1998 to determine the marketing practices of both handlers and producers for the 1996 crop year. Particular emphasis was placed on the types of contracting methods offered by these handlers. Both facility size and corporate structure were found to play a significant role in determining the types of marketing contracts offered as well as the frequency of usage by producers
A Chandra X-ray Study of Cygnus A - II. The Nucleus
We report Chandra ACIS and quasi-simultaneous RXTE observations of the
nearby, powerful radio galaxy Cygnus A, with the present paper focusing on the
properties of the active nucleus. In the Chandra observation, the hard (> a few
keV) X-ray emission is spatially unresolved with a size \approxlt 1 arcsec (1.5
kpc, H_0 = 50 km s^-1 Mpc^-1) and coincides with the radio and near infrared
nuclei. In contrast, the soft (< 2 keV) emission exhibits a bi-polar nebulosity
that aligns with the optical bi-polar continuum and emission-line structures
and approximately with the radio jet. In particular, the soft X-ray emission
corresponds very well with the [O III] \lambda 5007 and H\alpha + [N II]
\lambda\lambda 6548, 6583 nebulosity imaged with HST. At the location of the
nucleus there is only weak soft X-ray emission, an effect that may be intrinsic
or result from a dust lane that crosses the nucleus perpendicular to the source
axis. The spectra of the various X-ray components have been obtained by
simultaneous fits to the 6 detectors. The compact nucleus is detected to 100
keV and is well described by a heavily absorbed power law spectrum with
\Gamma_h = 1.52^{+0.12}_{-0.12} (similar to other narrow line radio galaxies)
and equivalent hydrogen column N_H (nuc) = 2.0^{+0.1}_{-0.2} \times 10^{23}
cm^-2.
(Abstract truncated).Comment: To be published in the Astrophysical Journal, v564 January 1, 2002
issue; 34 pages, 11 figures (1 color
Demonstrative Evidence - Winning Cases with Exhibits
Speaking on defense exhibits, Gordon Smith (J.D.’78) (left) said one should go through several versions of how to graphically depict something “to find the best delivery.” He discussed the finer points of using a timeline with assistance from Andy Scherffius (J.D.’74). Scherffius, who shared his thoughts on plaintiff exhibits, said the presentation of exhibits at a trial “has become an art and science of its own.
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