3,285 research outputs found
An inventory and condition survey of rangelands in the Ashburton River catchment, Western Australia
The inventory and condition survey of rangelands in the Ashburton River catchment, undertaken by the Department of Agriculture and Food, Western Australia (DAFWA) between 1976 and 1978, describes and maps the natural resources of the region’s pastoral leasehold land. This survey report provides a baseline record of the existence and condition of the natural area’s resources, to assist with the planning and implementation of land management practices. The report identified and described the condition of soils, landforms, vegetation, habitat, ecosystems, and declared plants and animals. It also assessed the impact of pastoralism and made land management recommendations. The area surveyed covers approximately 93 600km² and includes the catchment of the Ashburton River and part of the catchment of the Yannarie River. About 65% (61 130km²) of the area is occupied by 30 pastoral leases. The remaining 35% (32 470km²) consists of reserves of various kinds, and vacant crown land which is unsuitable for pastoral purposes. The worst areas of degredation and erosion are on the most valuable pasture lands. These areas are readily accessible, close to permanent water supplies and support attractive pastures. Therefore, they received preferential overuse in the early days of settlement, and sensitive parts are now seriously degraded
Systematics of Moduli Stabilization, Inflationary Dynamics and Power Spectrum
We study the scalar sector of type IIB superstring theory compactified on
Calabi-Yau orientifolds as a place to find a mechanism of inflation in the
early universe. In the large volume limit, one can stabilize the moduli in
stages using perturbative method. We relate the systematics of moduli
stabilization with methods to reduce the number of possible inflatons, which in
turn lead to a simpler inflation analysis. Calculating the order-of-magnitude
of terms in the equation of motion, we show that the methods are in fact valid.
We then give the examples where these methods are used in the literature. We
also show that there are effects of non-inflaton scalar fields on the scalar
power spectrum. For one of the two methods, these effects can be observed with
the current precision in experiments, while for the other method, the effects
might never be observable.Comment: 20 pages, JHEP style; v.2 and v.3: typos fixed, discussion and
references adde
A Search for a Sub-Earth Sized Companion to GJ 436 and a Novel Method to Calibrate Warm Spitzer IRAC Observations
We discovered evidence for a possible additional 0.75 R_Earth transiting
planet in the NASA EPOXI observations of the known M dwarf exoplanetary system
GJ 436. Based on an ephemeris determined from the EPOXI data, we predicted a
transit event in an extant Spitzer Space Telescope 8 micron data set of this
star. Our subsequent analysis of those Spitzer data confirmed the signal of the
predicted depth and at the predicted time, but we found that the transit depth
was dependent on the aperture used to perform the photometry. Based on these
suggestive findings, we gathered new Warm Spitzer Observations of GJ 436 at 4.5
microns spanning a time of transit predicted from the EPOXI and Spitzer 8
micron candidate events. The 4.5 micron data permit us to rule out a transit at
high confidence, and we conclude that the earlier candidate transit signals
resulted from correlated noise in the EPOXI and Spitzer 8 micron observations.
In the course of this investigation, we developed a novel method for correcting
the intrapixel sensitivity variations of the 3.6 and 4.5 micron channels of the
Infrared Array Camera (IRAC) instrument. We demonstrate the sensitivity of Warm
Spitzer observations of M dwarfs to confirm sub-Earth sized planets. Our
analysis will inform similar work that will be undertaken to use Warm Spitzer
observations to confirm rocky planets discovered by the Kepler mission.Comment: 22 pages, 8 figures, accepted for publication in PAS
Increase in Caesarean Deliveries after the Australian Private Health Insurance Incentive Policy Reforms
AbstractBackground: The Australian Private Health Insurance Incentive (PHII) policy reforms implemented in 1997–2000 increased PHI membership in Australia by 50%. Given the higher rate of obstetric interventions in privately insured patients, the reforms may have led to an increase in surgical deliveries and deliveries with longer hospital stays. We aimed to investigate the effect of the PHII policy introduction on birth characteristics in Western Australia (WA).Methods and Findings: All 230,276 birth admissions from January 1995 to March 2004 were identified from administrative birth and hospital data-systems held by the WA Department of Health. Average quarterly birth rates after the PHII introduction were estimated and compared with expected rates had the reforms not occurred. Rate and percentage differences (including 95% confidence intervals) were estimated separately for public and private patients, by mode of delivery, and by length of stay in hospital following birth. The PHII policy introduction was associated with a 20% (221.4 to219.3) decrease in public birth rates, a 51% (45.1 to 56.4) increase in private birth rates, a 5% (25.3 to 25.1) and 8% (28.9 to 27.9) decrease in unassisted and assisted vaginal deliveries respectively, a 5% (25.3 to 25.1) increase in caesarean sections with labour and 10% (8.0 to 11.7) increase in caesarean sections without labour. Similarly, birth rates where the infant stayed 0–3 days in hospital following birth decreased by 20% (221.5 to 218.5), but rates of births with .3 days inhospital increased by 15% (12.2 to 17.1).Conclusions: Following the PHII policy implementation in Australia, births in privately insured patients, caesarean deliveries and births with longer infant hospital stays increased. The reforms may not have been beneficial for quality obstetric care in Australia or the burden of Australian hospitals
Constraints in the Context of Induced-gravity Inflation
Constraints on the required flatness of the scalar potential for a
cousin-model to extended inflation are studied. It is shown that, unlike
earlier results, Induced-gravity Inflation can lead to successful inflation
with a very simple lagrangian and , rather than
as previously reported. A second order phase transition further
enables this model to escape the \lq big bubble' problem of extended inflation,
while retaining the latter's motivations based on the low-energy effective
lagrangians of supergravity, superstring, and Kaluza-Klein theories.Comment: 19 pp; 3 figures (not included -- available from author). Plain
LaTeX. In press in Physical Review
Recommended from our members
Incidence and public health burden of sunburn among beachgoers in the United States.
The beach environment creates many barriers to effective sun protection, putting beachgoers at risk for sunburn, a well-established risk factor for skin cancer. Our objective was to estimate incidence of sunburn among beachgoers and evaluate the relationship between sunburn incidence and sun-protective behaviors. A secondary analysis, of prospective cohorts at 12 locations within the U.S. from 2003 to 2009 (n = 75,614), were pooled to evaluate sunburn incidence 10-12 days after the beach visit. Behavioral and environmental conditions were cross-tabulated with sunburn incidence. Multivariable logistic regression was used to estimate the association between new sunburn and sun-protective behaviors. Overall, 13.1% of beachgoers reported sunburn. Those aged 13-18 years (16.5%), whites (16.0%), and those at beach locations along the Eastern Seaboard (16.1%), had the highest incidence of sunburn. For those spending ≥5 h in the sun, the use of multiple types of sun protection reduced odds of sunburn by 55% relative to those who used no sun protection (Odds Ratio = 0.45 (95% Confidence Interval:0.27-0.77)) after adjusting for skin type, age, and race. Acute health effects of sunburn tend to be mild and self-limiting, but potential long-term health consequences are more serious and costly. Efforts to encourage and support proper sun-protective behaviors, and increase access to shade, protective clothing, and sunscreen, can help prevent sunburn and reduce skin cancer risk among beachgoers
Solar District Cup Competition
The Solar District Cup is a two-semester design competition sponsored by the U.S. Dept. of Energy in which teams from across the nation compete to design the most efficient and cost effective solar plus storage system for a unique district case. The Embry Riddle team was tasked with designing such a system for New Mexico State University in Las Cruses, NM
On the Decoherence of Primordial Fluctuations During Inflation
We study the process whereby quantum cosmological perturbations become
classical within inflationary cosmology. By setting up a master-equation
formulation we show how quantum coherence for super-Hubble modes can be
destroyed by their coupling to the environment provided by sub-Hubble modes. We
identify what features the sub-Hubble environment must have in order to
decohere the longer wavelengths, and identify how the onset of decoherence (and
how long it takes) depends on the properties of the sub-Hubble physics which
forms the environment. Our results show that the decoherence process is largely
insensitive to the details of the coupling between the sub- and super-Hubble
scales. They also show how locality implies, quite generally, that the
decohered density matrix at late times is diagonal in the field representation
(as is implicitly assumed by extant calculations of inflationary density
perturbations). Our calculations also imply that decoherence can arise even for
couplings which are as weak as gravitational in strength.Comment: 31 pages, 1 figur
Detection of transit timing variations in excess of one hour in the Kepler multi-planet candidate system KOI 806 with the GTC
We report the detection of transit timing variations (TTVs) well in excess of
one hour in the Kepler multi-planet candidate system KOI 806. This system
exhibits transits consistent with three separate planets -- a Super-Earth, a
Jupiter, and a Saturn -- lying very nearly in a 1:2:5 resonance, respectively.
We used the Kepler public data archive and observations with the Gran
Telescopio de Canarias to compile the necessary photometry. For the largest
candidate planet (KOI 806.02) in this system, we detected a large transit
timing variation of -103.56.9 minutes against previously published
ephemeris. We did not obtain a strong detection of a transit color signature
consistent with a planet-sized object; however, we did not detect a color
difference in transit depth, either. The large TTV is consistent with
theoretical predictions that exoplanets in resonance can produce large transit
timing variations, particularly if the orbits are eccentric. The presence of
large TTVs among the bodies in this systems indicates that KOI806 is very
likely to be a planetary system. This is supported by the lack of a strong
color dependence in the transit depth, which would suggest a blended eclipsing
binary.Comment: 9 pages, 4 figures, accepted into A&A Letter
The architecture of the hierarchical triple star KOI 928 from eclipse timing variations seen in Kepler photometry
We present a hierarchical triple star system (KIC 9140402) where a low mass
eclipsing binary orbits a more massive third star. The orbital period of the
binary (4.98829 Days) is determined by the eclipse times seen in photometry
from NASA's Kepler spacecraft. The periodically changing tidal field, due to
the eccentric orbit of the binary about the tertiary, causes a change in the
orbital period of the binary. The resulting eclipse timing variations provide
insight into the dynamics and architecture of this system and allow the
inference of the total mass of the binary ()
and the orbital parameters of the binary about the central star.Comment: Submitted to MNRAS Letters. Additional tables with eclipse times are
included here. The Kepler data that was used for the analysis of this system
(Q1 through Q6) will be available on MAST after June 27, 201
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