9,817 research outputs found
Gene-flow between populations of cotton bollworm Helicoverpa armigera (Lepidoptera: Noctuidae) is highly variable between years
Both large and small scale migrations of Helicoverpa armigera HĂŒbner in Australia were investigated using AMOVA analysis and genetic assignment tests. Five microsatellite loci were screened across 3142 individuals from 16 localities in eight major cotton and grain growing regions within Australia, over a 38-month period (November 1999 to January 2003). From November 1999 to March 2001 relatively low levels of migration were characterized between growing regions. Substantially higher than average gene-flow rates and limited differentiation between cropping regions characterized the period from April 2001 to March 2002. A reduced migration rate in the year from April 2002 to March 2003 resulted in significant genetic structuring between cropping regions. This differentiation was established within two or three generations. Genetic drift alone is unlikely to drive genetic differentiation over such a small number of generations, unless it is accompanied by extreme bottlenecks and/or selection. Helicoverpa armigera in Australia demonstrated isolation by distance, so immigration into cropping regions is more likely to come from nearby regions than from afar. This effect was most pronounced in years with limited migration. However, there is evidence of long distance dispersal events in periods of high migration (April 2001âMarch 2002). The implications of highly variable migration patterns for resistance management are considered.K.D. Scott, K.S. Wilkinson, N. Lawrence, C.L. Lange, L.J. Scott, M.A. Merritt, A.J. Lowe and G.C Graha
Recent Outbursts from the Transient X-Ray Pulsar Cep X-4 (GS 2138+56)
We report on X-ray observations of the 66 s period transient X-ray pulsar Cep
X-4 (GS 2138+56) with the Burst and Transient Source Experiment (BATSE) on the
Compton Gamma-Ray Observatory (CGRO) and with the Rossi X-ray Timing Explorer
(RXTE). Two outbursts from Cep X-4 were observed with BATSE in 1993 June-July
and 1997 July. Pulse frequencies of 15.0941 +/- 0.0002 mHz on 1993 June 25 (MJD
49,163) and 15.0882 +/- 0.0002 mHz on 1997 July 12 (MJD 50,641) were each
measured from 2 day spans of BATSE data near each outburst's peak. Cep X-4
showed an average spin down rate of (-4.14 +/- 0.08)*10^(-14) Hz/s between the
1993 and 1997 outbursts. After BATSE could no longer detect Cep X-4, public
observations were performed on 1997 July 18 & 25 with the Proportional Counter
Array (PCA) on RXTE. A pulse frequency of 15.088 +/- 0.004 mHz was measured
from observations on 1997 July 18 (MJD 50,647). Significant aperiodic noise,
with an rms variance of ~18% in the frequency range 0.01-1.0 Hz was observed on
both days. Energy and intensity dependent pulse shape variations were also seen
in these data. Recently published optical observations associate Cep X-4 with a
Be companion star. If all 4 outbursts observed from Cep X-4 are assumed to
occur at the same orbital phase, we find that the orbital period is between 23
days and 147.3 days.Comment: 19 pages (LaTeX) including 9 figures. Accepted for publication in the
Astrophysical Journa
The effects of extended public transport operating hours and venue lockout policies on drinking-related harms in Melbourne, Australia: Results from SimDrink, an agent-based simulation model.
Background: The late-night accessibility of entertainment precincts is a contributing factor to acute drinking-related harms. Using computer simulation we test the effects of improved public transport (PT) and venue lockouts on verbal aggression, consumption-related harms and transport-related harms among a population of young adults engaging in heavy drinking in Melbourne. Methods: Using an agent-based model we implemented: a two-hour PT extension/24-hour PT; 1 am/3 am venue lockouts; and combinations of both. Outcomes determined for outer-urban (OU) and inner-city (IC) residents were: the number of incidents of verbal aggression inside public and private venues; the number of people ejected from public venues for being intoxicated; and the percentage of people experiencing verbal aggression, consumption-related harms and transport-related harms. Results: All-night PT reduced verbal aggression in the model by 21% but displaced some incidents among OU residents from private to public settings. Comparatively, 1 am lockouts reduced verbal aggression in the model by 19% but led to IC residents spending more time in private rather than public venues where their consumption-related harms increased. Extending PT by 2 h had similar outcomes to 24-hour PT except with fewer incidents of verbal aggression displaced. Although 3 am lockouts were inferior to 1 am lockouts, when modelled in combination with any extension of PT both policies were similar. Conclusions: A two-hour extension of PT is likely to be more effective in reducing verbal aggression and consumption-related harms than venue lockouts. Modelling a further extension of PT to 24 h had minimal additional benefits but the potential to displace incidents of verbal aggression among OU residents from private to public venues
Cost-effectiveness of uterine tamponade devices for the treatment of postpartum hemorrhage: A systematic review
Background: Uterine tamponade is widely promoted for treating refractory postpartum hemorrhage (PPH); however, its costâeffectiveness may vary depending on unit costs and setting. Objective: To review available data on costâeffectiveness of uterine tamponade devices when used for PPH treatment. Search strategy: PubMed and EMBASE were searched (1980 to January 2020), as well as the National Health Services Economic Evaluation database from inception (1995) to March 2015. Selection criteria: Eligible studies were any type of economic evaluation, or effectiveâ ness studies that provided cost or economic data. Data collection and analysis: Two reviewers independently screened studies, extracted data, and assessed quality. Main results: Eleven studies using a range of devices (condom catheter, uterine sucâ tion devices, Bakri, Inpress, Ellavi) were identified. Cost of condom catheter devices or kits ranged from US6, whereas purposeâdesigned device costs were up to US$400. Two studies that took a health system perspective assessed the costâ effectiveness of using uterine balloon tamponade and suggested that it was highly costâ effective because of the low cost per disabilityâadjusted lifeâyear averted, although both used effect estimates from case series. Conclusions: Evidence on the costâeffectiveness of uterine tamponade devices was limited and not generalizable. Rigorous economic evaluations based on updated effect estimates are needed.Fil: Vogel, Joshua P.. Monash University; AustraliaFil: Wilson, Alyce N.. Burnet Institute; AustraliaFil: Scott, Nick. Monash University; Australia. Burnet Institute; AustraliaFil: Widmer, Mariana. Organizacion Mundial de la Salud; ArgentinaFil: Althabe, Fernando. Organizacion Mundial de la Salud; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Centro de Investigaciones en EpidemiologĂa y Salud PĂșblica. Instituto de Efectividad ClĂnica y Sanitaria. Centro de Investigaciones en EpidemiologĂa y Salud PĂșblica; ArgentinaFil: Oladapo, Olufemi T.. Organizacion Mundial de la Salud; Argentin
AzTEC Millimetre Survey of the COSMOS Field - II. Source Count Overdensity and Correlations with Large-Scale Structure
We report an over-density of bright sub-millimetre galaxies (SMGs) in the
0.15 sq. deg. AzTEC/COSMOS survey and a spatial correlation between the SMGs
and the optical-IR galaxy density at z <~ 1.1. This portion of the COSMOS field
shows a ~ 3-sigma over-density of robust SMG detections when compared to a
background, or "blankfield", population model that is consistent with SMG
surveys of fields with no extragalactic bias. The SMG over-density is most
significant in the number of very bright detections (14 sources with measured
fluxes S(1.1mm) > 6 mJy), which is entirely incompatible with sample variance
within our adopted blank-field number densities and infers an over-density
significance of >> 4. We find that the over-density and spatial correlation to
optical-IR galaxy density are most consistent with lensing of a background SMG
population by foreground mass structures along the line of sight, rather than
physical association of the SMGs with the z <~ 1.1 galaxies/clusters. The SMG
positions are only weakly correlated with weak-lensing maps, suggesting that
the dominant sources of correlation are individual galaxies and the more
tenuous structures in the region and not the massive and compact clusters.
These results highlight the important roles cosmic variance and large-scale
structure can play in the study of SMGs.Comment: 12 pages, 11 figures, 2 tables, accepted for publication in MNRA
VectorBase: improvements to a bioinformatics resource for invertebrate vector genomics.
VectorBase (http://www.vectorbase.org) is a NIAID-supported bioinformatics resource for invertebrate vectors of human pathogens. It hosts data for nine genomes: mosquitoes (three Anopheles gambiae genomes, Aedes aegypti and Culex quinquefasciatus), tick (Ixodes scapularis), body louse (Pediculus humanus), kissing bug (Rhodnius prolixus) and tsetse fly (Glossina morsitans). Hosted data range from genomic features and expression data to population genetics and ontologies. We describe improvements and integration of new data that expand our taxonomic coverage. Releases are bi-monthly and include the delivery of preliminary data for emerging genomes. Frequent updates of the genome browser provide VectorBase users with increasing options for visualizing their own high-throughput data. One major development is a new population biology resource for storing genomic variations, insecticide resistance data and their associated metadata. It takes advantage of improved ontologies and controlled vocabularies. Combined, these new features ensure timely release of multiple types of data in the public domain while helping overcome the bottlenecks of bioinformatics and annotation by engaging with our user community
The Outbursts and Orbit of the Accreting Pulsar GS 1843-02 = 2S 1845-024
We present observations of a series of 10 outbursts of pulsed hard X-ray flux
from the transient 10.6 mHz accreting pulsar GS 1843-02, using the Burst and
Transient Source Experiment on the Compton Gamma Ray Observatory. These
outbursts occurred regularly every 242 days, coincident with the ephemeris of
the periodic transient GRO J1849-03 (Zhang et al. 1996), which has recently
been identified with the SAS 3 source 2S 1845-024 (Soffitta et al. 1998). Our
pulsed detection provides the first clear identification of GS 1843-02 with 2S
1845-024. We present a pulse timing analysis which shows that the 2S 1845-024
outbursts occur near the periastron passage of the neutron star's highly
eccentric (e = 0.88+-0.01) 242.18+-0.01 day period binary orbit about a high
mass (M > 7 solar masses) companion. The orbit and transient outburst pattern
strongly suggest the pulsar is in a binary system with a Be star. Our
observations show a long-term spin-up trend, with most of the spin-up occurring
during the outbursts. From the measured spin-up rates and inferred luminosities
we conclude that an accretion disk is present during the outbursts.Comment: Accepted for publication in Astrophysical Journa
AzTEC millimeter survey of the COSMOS field - III. Source catalog over 0.72 sq. deg. and plausible boosting by large-scale structure
We present a 0.72 sq. deg. contiguous 1.1mm survey in the central area of the
COSMOS field carried out to a 1sigma ~ 1.26 mJy/beam depth with the AzTEC
camera mounted on the 10m Atacama Submillimeter Telescope Experiment (ASTE). We
have uncovered 189 candidate sources at a signal-to-noise ratio S/N >= 3.5, out
of which 129, with S/N >= 4, can be considered to have little chance of being
spurious (< 2 per cent). We present the number counts derived with this survey,
which show a significant excess of sources when compared to the number counts
derived from the ~0.5 sq. deg. area sampled at similar depths in the Scuba HAlf
Degree Extragalactic Survey (SHADES, Austermann et al. 2010). They are,
however, consistent with those derived from fields that were considered too
small to characterize the overall blank-field population. We identify
differences to be more significant in the S > 5 mJy regime, and demonstrate
that these excesses in number counts are related to the areas where galaxies at
redshifts z < 1.1 are more densely clustered. The positions of optical-IR
galaxies in the redshift interval 0.6 < z < 0.75 are the ones that show the
strongest correlation with the positions of the 1.1mm bright population (S > 5
mJy), a result which does not depend exclusively on the presence of rich
clusters within the survey sampled area. The most likely explanation for the
observed excess in number counts at 1.1mm is galaxy-galaxy and galaxy-group
lensing at moderate amplification levels, that increases in amplitude as one
samples larger and larger flux densities. This effect should also be detectable
in other high redshift populations.Comment: 21 pages, 17 figures, accepted for publication in MNRA
Fractal Structures and Scaling Laws in the Universe: Statistical Mechanics of the Self-Gravitating Gas
Fractal structures are observed in the universe in two very different ways.
Firstly, in the gas forming the cold interstellar medium in scales from 10^{-4}
pc till 100 pc. Secondly, the galaxy distribution has been observed to be
fractal in scales up to hundreds of Mpc. We give here a short review of the
statistical mechanical (and field theoretical) approach developed by us. We
consider a non-relativistic self-gravitating gas in thermal equilibrium at
temperature T inside a volume V. The statistical mechanics of such system has
special features and, as is known, the thermodynamical limit does not exist in
its customary form. Moreover, the treatments through microcanonical, canonical
and grand canonical ensembles yield different results.We present here for the
first time the equation of state for the self-gravitating gas in the canonical
ensemble. We find that it has the form p = [N T/ V] f(eta), where p is the
pressure, N is the number of particles and \eta \equiv {G m^2 N \over V^{1/3}
T}. The N \to\infty and V \to\infty limit exists keeping \eta fixed. We compute
the function f(\eta) using Monte Carlo simulations and for small eta
analytically. We compute the thermodynamic quantities of the system as free
energy, entropy, chemical potential, specific heat, compressibility and speed
of sound. We reproduce the well-known gravitational phase transition associated
to the Jeans' instability. Namely, a gaseous phase for eta < eta_c and a
condensed phase for eta > eta_c. Moreover, we derive the precise behaviour of
the physical quantities near the transition. In particular, the pressure
vanishes as p \sim(eta_c-eta)^B with B \sim 0.2 and eta_c \sim 1.6 and the
energy fluctuations diverge as \sim(eta_c-eta)^{B-1}. The speed of sound
decreases monotonically and approaches the value sqrt{T/6} at the transition.Comment: Invited paper to the special issue of the `Journal of Chaos, Solitons
and Fractals': `Superstrings, M, F, S...theory', M. S El Naschie and C.
Castro, Editors. Latex file, 16 pages plus three .ps figure
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