169 research outputs found
X-ray spectroscopy of the IP PQ Gem
Using RXTE and ASCA data, we investigate the roles played by occultation and absorption in the X-ray spin pulse profile of the intermediate polar PQ Gem. From the X-ray light curves and phase-resolved spectroscopy, we find that the intensity variations are the result of a combination of varying degrees of absorption and the accretion regions rotating behind the visible face of the white dwarf. These occultation and absorption effects are consistent with those expected from the accretion structures calculated from optical polarization data. We can reproduce the changes in absorber covering fraction either from geometrical effects, or by considering that the material in the leading edge of the accretion curtain is more finely fragmented than in other parts of the curtain. We determine a white dwarf mass of ∼ 1.2 using the RXTE data
Pasture Condition Scoring
A pasture condition score sheet has been developed for use in the United States. It has rating criteria for key indicators that are used to ascertain if some areas of pasture management could be improved. It can also help evaluate what is causing less than desirable pasture conditions. Pasture condition scoring involves the visual and tactual evaluation of ten indicators that rate a pasture\u27s overall condition. The ten indicators are: percent desirable plants, plant cover, plant diversity, plant residue, plant vigor, percent legume, uniformity of use, livestock concentration areas, soil compaction, and erosion (sheet and rill, gully, streambank and shoreline, and wind). Six causative factors that impact pasture plant growth and vigor are also rated: soil fertility status, soil pH status, severity of use, forage species suitability, episodic climatic conditions, and insect and disease pressure. Regionally, levels of salinity, sodicity, and toxic elements (e.g. aluminum) can also be measured and rated where they commonly affect pasture productivity, stability, and forage species selection. Indicators and causative factors receiving the lowest scores can be focused upon and corrective actions taken as warranted
The Mind-Body Connection: The Association between Adolescent Locus of Control and Indicators of Physical Health
Locus of control (LOC) describes an individual’s generalized beliefs or expectancies that their reinforcements are under internal versus external control (1). An individual exhibits either an internal or external LOC. This study examines the link between LOC and selected health risk factors in adolescents. A convenience sample of 167 high school physical education students completed a 13-item LOC questionnaire based on Rotter’s 1966 instrument.
Various anthropometric measurements, blood pressure, body mass index (BMI), and body fat were recorded on all subjects. A subsample of 61 female students received blood chemistry analysis that included a lipid profile, hemoglobin A1c (HbA1c), Apo A-1, and Apo B. Mean body fat percents and LOC scores were significantly correlated (r=0.208; p=0.006), and mean body fat percent was significantly different between the internal and external LOC groups (p=0.039). Regression equations were developed to predict HbA1c from hip circumference and LOC, and to predict Apo A-1 from LOC. Predictability was 99.8% and 97% respectively.
We conclude that, with further research, LOC may prove to be a useful tool for screening large groups of adolescents for disease risk
Forage Suitability Group Report: A Tool for Grassland Management
Forage suitability groups (FSG\u27s) are USDA-Natural Resources Conservation Service (NRCS) interpretative reports used to develop conservation plans for forage-producing farms and ranches and provide grassland resource information to producers. These electronic reports use soil properties and climatic data to develop forage selection, management recommendations, seasonal distribution of growth, and yield potentials for groups of soil map unit components that have like agronomic characteristics. The information contained in a FSG report can help the user develop proper livestock-forage balances, grazing management plans, pasture and haycrop renovation options, and land treatment measures
X-ray Spectroscopy of the IP PQ Gem
Using RXTE and ASCA data, we investigate the roles played by occultation and
absorption in the X-ray spin pulse profile of the Intermediate Polar PQ Gem.
From the X-ray light curves and phase-resolved spectroscopy, we find that the
intensity variations are due to a combination of varying degrees of absorption
and the accretion regions rotating behind the visible face of the white dwarf.
These occultation and absorption effects are consistent with those expected
from the accretion structures calculated from optical polarisation data. We can
reproduce the changes in absorber covering fraction either from geometrical
effects, or by considering that the material in the leading edge of the
accretion curtain is more finely fragmented than in other parts of the curtain.
We determine a white dwarf mass of ~1.2 using the RXTE data.Comment: Accepted for publication in MNRA
Polarized QPOs from the INTEGRAL polar IGRJ14536-5522 (=Swift J1453.4-5524)
We report optical spectroscopy and high speed photometry and polarimetry of
the INTEGRAL source IGRJ14536-5522 (=Swift J1453.4-5524). The photometry,
polarimetry and spectroscopy are modulated on an orbital period of 3.1564(1)
hours. Orbital circularly polarized modulations are seen from 0 to -18 per
cent, unambiguously identifying IGRJ14536-5522 as a polar.
Some of the high speed photometric data show modulations that are consistent
with quasi-periodic oscillations (QPOs) on the order of 5-6 minutes.
Furthermore, for the first time, we detect the (5-6) minute QPOs in the
circular polarimetry. We discuss the possible origins of these QPOs. We also
include details of HIPPO, a new high-speed photo-polarimeter used for some of
our observations.Comment: Accepted for publication by MNRAS. The paper contains 7 figures and 1
tabl
Anomalous blocking over Greenland preceded the 2013 extreme early melt of local sea ice
The Arctic marine environment is undergoing a transition from thick multi-year to first-year sea ice cover with coincident lengthening of the melt season. Such changes are evident in the Baffin Bay-Davis Strait-Labrador Sea (BDL) region where melt onset has occurred ~8 days decade-1 earlier from 1979-2015. A series of anomalously early events has occurred since the mid-1990s, overlapping a period of increased upper-air ridging across Greenland and the northwestern North Atlantic. We investigate an extreme early melt event observed in spring 2013 below the 1981-2010 melt climatology), with respect to preceding sub-seasonal mid-tropospheric circulation conditions as described by a daily Greenland Blocking Index (GBI).
The 40-days prior to the 2013 BDL melt onset are characterized by a persistent, strong 500 hPa anticyclone over the region (GBI >+1 on >75% of days). This circulation pattern advected warm air from northeastern Canada and the northwestern Atlantic poleward onto the thin, first-year sea ice and caused melt about 50 days earlier than normal. The episodic increase in the ridging atmospheric pattern near western Greenland as in 2013, exemplified by large positive GBI values, is an important recent process impacting the atmospheric circulation over a North Atlantic cryosphere undergoing accelerated regional climate change
XMM-Newton confirmation of a new intermediate polar: XMMU J185330.7-012815
We report the results from a detailed spectro-imaging and temporal analysis
of an archival XMM-Newton observation of a new intermediate polar XMMU
J185330.7-012815. Its X-ray spectrum can be well-described by a
multi-temperature thermal plasma model with the K-lines of heavy elements
clearly detected. Possible counterparts of XMMU J185330.7-012815 have been
identified in optical and UV bands. The low value of the inferred X-ray-to-UV
and X-ray-to-optical flux ratios help to safely rule out the possibility as an
isolated neutron star. We confirm the X-ray periodicity of ~238 s, but
different from the previous preliminary result, we do not find any convincing
evidence of phase-shift in this observation. We further investigate its
properties through an energy-resolved temporal analysis and find the pulsed
fraction monotonically increases with energy.Comment: 9 pages, 4 figures, 1 table, accepted for publication in MNRA
The SKA Particle Array Prototype: The First Particle Detector at the Murchison Radio-astronomy Observatory
We report on the design, deployment, and first results from a scintillation
detector deployed at the Murchison Radio-astronomy Observatory (MRO). The
detector is a prototype for a larger array -- the Square Kilometre Array
Particle Array (SKAPA) -- planned to allow the radio-detection of cosmic rays
with the Murchison Widefield Array and the low-frequency component of the
Square Kilometre Array. The prototype design has been driven by stringent
limits on radio emissions at the MRO, and to ensure survivability in a desert
environment. Using data taken from Nov.\ 2018 to Feb.\ 2019, we characterize
the detector response while accounting for the effects of temperature
fluctuations, and calibrate the sensitivity of the prototype detector to
through-going muons. This verifies the feasibility of cosmic ray detection at
the MRO. We then estimate the required parameters of a planned array of eight
such detectors to be used to trigger radio observations by the Murchison
Widefield Array.Comment: 17 pages, 14 figures, 3 table
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