2,049 research outputs found
Seasonal Variations in Water Quality Parameters of the Mississippi River near St. Cloud, MN
ABSTRACT - Water quality parameters were monitored in the Mississippi River and three tributaries (Harris Channel, Watab Creek, and Sauk River) from July 1980 to April 1981. Results were correlated with water temperature and discharge to assess seasonal changes. Effects of tributary inflow on the river were determined. Planktonic carbon was estimated with the firefly luciferin-luciferase system which measures adenosine triphosphate extracted from viable cells. Particulate organic matter, planktonic carbon, and percentage viable carbon were correlated with temperature (p ~ 0.6) while nitrate plus nitrite was inversely correlated with temperature and discharge. Only the Sauk River affected the water quality of the Mississippi River by adding elevated levels of dissolved electrolytes, total phosphorus, particulate organic matter, and planktonic carbon. Relatively low levels of planktonic carbon (155 μg/1) in the river indicated good water quality. Seasonal changes in water quality parameters of rivers must be considered in designing useful monitoring programs
Herschel-SPIRE-Fourier Transform Spectroscopy of the nearby spiral galaxy IC342
We present observations of the nearby spiral galaxy IC342 with the Herschel
Spectral and Photometric Imaging Receiver (SPIRE) Fourier Transform
Spectrometer. The spectral range afforded by SPIRE, 196-671 microns, allows us
to access a number of 12CO lines from J=4--3 to J=13--12 with the highest J
transitions observed for the first time. In addition we present measurements of
13CO, [CI] and [NII]. We use a radiative transfer code coupled with Bayesian
likelihood analysis to model and constrain the temperature, density and column
density of the gas. We find two 12CO components, one at 35 K and one at 400 K
with CO column densities of 6.3x10^{17} cm^{-2} and 0.4x10^{17} cm^{-2} and CO
gas masses of 1.26x10^{7} Msolar and 0.15x10^{7} Msolar, for the cold and warm
components, respectively. The inclusion of the high-J 12CO line observations,
indicate the existence of a much warmer gas component (~400 K) confirming
earlier findings from H_{2} rotational line analysis from ISO and Spitzer. The
mass of the warm gas is 10% of the cold gas, but it likely dominates the CO
luminosity. In addition, we detect strong emission from [NII] 205microns and
the {3}P_{1}->{3}P_{0} and {3}P_{2} ->{3}P_{1} [CI] lines at 370 and 608
microns, respectively. The measured 12CO line ratios can be explained by
Photon-dominated region (PDR) models although additional heating by e.g. cosmic
rays cannot be excluded. The measured [CI] line ratio together with the derived
[C] column density of 2.1x10^{17} cm^{-2} and the fact that [CI] is weaker than
CO emission in IC342 suggests that [CI] likely arises in a thin layer on the
outside of the CO emitting molecular clouds consistent with PDRs playing an
important role.Comment: 9 pages, 8 figures, accepted for publication in Monthly Notices of
the Royal Astronomical Society (MNRAS
Personality heterogeneity in female adolescent inpatients with features of eating disorders
Objective: This study examined evidence for personality variability in adolescents with eating disorder features in light of previous evidence that personality variability in adult women with eating disorder symptoms carries important clinical implications.
Method: Millon Adolescent Clinical Inventory personality data from adolescent girls with disturbed eating who were psychiatrically hospitalized were cluster analyzed, and resulting groups were compared in eating and comorbid psychopathology.
Results: Three subgroups were identified among the 153 patients with eating disorder features: high functioning, internalizing, and externalizing. The internalizing group was marked by eating-related and mood dysfunction; the externalizing group by elevated eating and mood psychopathology as well as impulsivity, aggression, and substance use; and the high-functioning group by lower levels of psychopathology and relatively high self-esteem.
Conclusions: These findings converge with previous research using different personality models in adult samples and highlight the clinical use of considering personality heterogeneity among adolescent and adult women with disturbed eating
Evidence for field change in oral cancer based on cytokeratin expression.
It was hypothesised that one may be able to visualise field changes, which are proposed to exist around tumours, as alterations in keratin intermediate filament protein expression. Standard immunohistochemical analysis using a panel of monoclonal anti-keratin antibodies was applied to fresh tissue sections to look for subtle changes in epithelial differentiation not visible in H&E sections. Such changes were observed in clinically normal epithelium from oral cancer patients, involving primarily substantial expression of keratins K8/K7 (using CAM 5.2) in the basal cells of 12 out of 34 biopsies, and also a trend towards a reduction in the complexity of keratin differentiation. Monitoring such changes may prove to be a valuable adjunct to conventional H&E staining if found to have prognostic and diagnostic significance
A novel sputtering technique: Inductively Coupled Impulse Sputtering (ICIS)
Sputtering magnetic materials with magnetron based systems has the disadvantage of field quenching and variation of alloy composition with target erosion. The advantage of eliminating magnetic fields in the chamber is that this enables sputtered particles to move along the electric field more uniformly. Inductively coupled impulse sputtering (ICIS) is a form of high power impulse magnetron sputtering (HIPIMS) without a magnetic field where a high density plasma is produced by a high power radio frequency (RF) coil in order to sputter the target and ionise the metal vapour. In this emerging technology, the effects of power and pressure on the ionisation and deposition process are not known. The setup comprises of a 13.56 MHz pulsed RF coil pulsed with a duty cycle of 25 %. A pulsed DC voltage of 1900 V was applied to the cathode to attract Argon ions and initiate sputtering. Optical emission spectra (OES) for Cu and Ti neutrals and ions at constant pressure show a linear intensity increase for peak RF powers of 500 W – 3400 W and a steep drop of intensity for a power of 4500 W. Argon neutrals show a linear increase for powers of 500 W – 2300 W and a saturation of intensity between 2300 W – 4500 W. The influence of pressure on the process was studied at a constant peak RF power of 2300 W. With increasing pressure the ionisation degree increased. The microstructure of the coatings shows globular growth at 2.95×10−2 mbar and large-grain columnar growth at 1.2×10−1 mbar. Bottom coverage of unbiased vias with a width of 0.360 μm and aspect ratio of 2.5:1 increased from 15 % to 20 % for this pressure range. The current work has shown that the concept of combining a RF powered coil with a magnet-free high voltage pulsed DC powered cathode is feasible and produces very stable plasma. The experiments have shown a significant influence of power and pressure on the plasma and coating microstructure
Transfer of motor and perceptual skills from basketball to darts
The quiet eye is a perceptual skill associated with expertise and superior performance; however, little is known about the transfer of quiet eye across domains. We attempted to replicate previous skill-based differences in quiet eye and investigated whether transfer of motor and perceptual skills occurs between similar tasks. Throwing accuracy and quiet eye duration for skilled and less-skilled basketball players were examined in basketball free throw shooting and the transfer task of dart throwing. Skilled basketball players showed significantly higher throwing accuracy and longer quiet eye duration in the basketball free throw task compared to their less-skilled counterparts. Further, skilled basketball players showed positive transfer from basketball to dart throwing in accuracy but not in quiet eye duration. Our results raise interesting questions regarding the measurement of transfer between skills
Calibration of the Herschel SPIRE Fourier Transform Spectrometer
The Herschel SPIRE instrument consists of an imaging photometric camera and
an imaging Fourier Transform Spectrometer (FTS), both operating over a
frequency range of 450-1550 GHz. In this paper, we briefly review the FTS
design, operation, and data reduction, and describe in detail the approach
taken to relative calibration (removal of instrument signatures) and absolute
calibration against standard astronomical sources. The calibration scheme
assumes a spatially extended source and uses the Herschel telescope as primary
calibrator. Conversion from extended to point-source calibration is carried out
using observations of the planet Uranus. The model of the telescope emission is
shown to be accurate to within 6% and repeatable to better than 0.06% and, by
comparison with models of Mars and Neptune, the Uranus model is shown to be
accurate to within 3%. Multiple observations of a number of point-like sources
show that the repeatability of the calibration is better than 1%, if the
effects of the satellite absolute pointing error (APE) are corrected. The
satellite APE leads to a decrement in the derived flux, which can be up to ~10%
(1 sigma) at the high-frequency end of the SPIRE range in the first part of the
mission, and ~4% after Herschel operational day 1011. The lower frequency range
of the SPIRE band is unaffected by this pointing error due to the larger beam
size. Overall, for well-pointed, point-like sources, the absolute flux
calibration is better than 6%, and for extended sources where mapping is
required it is better than 7%.Comment: 20 pages, 18 figures, accepted for publication in MNRA
Systematic characterisation of the Herschel SPIRE Fourier Transform Spectrometer
A systematic programme of calibration observations was carried out to monitor
the performance of the SPIRE FTS instrument on board the Herschel Space
Observatory. Observations of planets (including the prime point-source
calibrator, Uranus), asteroids, line sources, dark sky, and cross-calibration
sources were made in order to monitor repeatability and sensitivity, and to
improve FTS calibration. We present a complete analysis of the full set of
calibration observations and use them to assess the performance of the FTS.
Particular care is taken to understand and separate out the effect of pointing
uncertainties, including the position of the internal beam steering mirror for
sparse observations in the early part of the mission. The repeatability of
spectral line centre positions is <5km/s, for lines with signal-to-noise ratios
>40, corresponding to <0.5-2.0% of a resolution element. For spectral line
flux, the repeatability is better than 6%, which improves to 1-2% for spectra
corrected for pointing offsets. The continuum repeatability is 4.4% for the SLW
band and 13.6% for the SSW band, which reduces to ~1% once the data have been
corrected for pointing offsets. Observations of dark sky were used to assess
the sensitivity and the systematic offset in the continuum, both of which were
found to be consistent across the FTS detector arrays. The average point-source
calibrated sensitivity for the centre detectors is 0.20 and 0.21 Jy [1 sigma; 1
hour], for SLW and SSW. The average continuum offset is 0.40 Jy for the SLW
band and 0.28 Jy for the SSW band.Comment: 41 pages, 37 figures, 32 tables. Accepted for publication in MNRA
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