1,475 research outputs found
Status of Acropora palmata Populations off the Coast of South Caicos, Turks and Caicos Islands
This study is the first detailed assessment of A. palmata populations of the Turks and Caicos Islands. A total of 203 individual colonies and 62 thickets were tagged on five shallow reefs. Depth, percentages of living tissue, recent mortality and old skeleton were estimated. Presence of disease and predatory snails was noted, and disease spread and grazing rates of the snails estimated. Colonies were found in depths of 0.2 - 4 m. Living tissue for individual colonies (75.9% ± 2.2 SE) was significantly greater than for thickets (58.6% ± 3.6) and in both cases exceeded old skeleton (individuals: 22.7% ± 2.1 SE, thickets: 38.0% ± 3.4 SE). Percentage of recent mortality was very low (individuals: 1.3% ± 0.3 SE, thickets: 3.4% ± 0.7%). We found WBD (n = 2), white pox disease a (WPDa) (n = 7) and white pox disease b (WPDb) (n = 14) with greatly varying spreading rates. The WBD infected colonies showed an atypical spread from the top of the branch towards the base. Coralliophila abbreviata and C. caribaea affected 3 .7 54.7% of the populations (grazing rate: 4.29 cm 2 /day/snail ± 1.16 SE). South Caicosâ A. palmata populations are still in good condition, though increasing human disturbances combined with disease and predatory snails may threaten these populations
Environmental controls on daytime net community calcification on a Red Sea reef flat
Coral growth and carbonate accumulation form the foundation of the coral reef ecosystem. Changes in environmental conditions due to coastal development, climate change, and ocean acidification may pose a threat to net carbonate production in the near future. Controlled laboratory studies demonstrate that calcification by corals and coralline algae is sensitive to changes in aragonite saturation state (Ωa), as well as temperature, light, and nutrition. Studies also show that the dissolution rate of carbonate substrates is impacted by changes in carbonate chemistry. The sensitivity of coral reefs to these parameters must be confirmed and quantified in the natural environment in order to predict how coral reefs will respond to local and global changes, particularly ocean acidification. We estimated the daytime hourly net community metabolic rates, both net community calcification (NCC) and net community productivity (NCP), at Sheltered Reef, an offshore platform reef in the central Red Sea. Average NCC was 8 ± 3 mmol m[superscript â2] h[superscript â1] in December 2010 and 11 ± 1 mmol m[superscript â2] h[superscript â1] in May 2011, and NCP was 21 ± 7 mmol m[superscript â2] h[superscript â1] in December 2010 and 44 ± 4 mmol m[superscript â2] h[superscript â1] in May 2011. We also monitored a suite of physical and chemical properties to help relate the rates at Sheltered Reef to published rates from other sites. While previous research shows that short-term field studies investigating the NCCâΩa relationship have differing results due to confounding factors, it is important to continue estimating NCC in different places, seasons, and years, in order to monitor changes in NCC versus Ω in space and time, and to ultimately resolve a broader understanding of this relationship.National Science Foundation (U.S.) (Graduate Research Fellowship
Promoting sustainability in quality improvement: an evaluation of a web-based continuing education program in blood pressure measurement.
BACKGROUND: The accuracy of blood pressure measurement is variable in office-based settings. Even when staff training programs are effective, knowledge and skills decay over time, supporting the need for ongoing staff training. We evaluated whether a web-based continuing education program in blood pressure measurement reinforced knowledge and skills among clinical staff and promoted sustainability of an existing quality improvement program.
METHODS: Medical assistants and nurses at six primary care clinics within a health system enrolled in a 30-min online educational program designed to refresh their knowledge of blood pressure measurement. A 20-question pre- and post-intervention survey addressed learners\u27 knowledge and attitudes. Direct observation of blood pressure measurement technique before and after the intervention was performed. Differences in responses to pre- and post-module knowledge and attitudes questions and in observation data were analyzed using chi-square tests and simple logistic regression.
RESULTS: All 88 clinical staff members participated in the program and completed the evaluation survey. Participants answered 80.6% of questions correctly before the module and 93.4% afterwards (pâ\u3câ0.01). Scores improved significantly among staff from all job types. Licensed practical nurses and staff who had been in their current job at least a year were more likely to answer questions correctly than registered nurses and those in their current job less than a year. Attitudes toward correct blood pressure measurement were high at baseline and did not improve significantly. Prior to the intervention, staff adhered to 9 of 18 elements of the recommended technique during at least 90% of observations. Following the program, staff was more likely to explain the protocol, provide a rest period, measure an average blood pressure, and record the average blood pressure, but less likely to measure blood pressure with the arm at heart level and use the right arm.
CONCLUSIONS: We designed, implemented, and evaluated a web-based educational program to improve knowledge, skills, and attitudes in blood pressure measurement and use of an automated device among nurses and medical assistants in ambulatory care. The program reinforced knowledge related to recommended blood pressure measurement technique.
TRIAL REGISTRATION: Retrospectively registered with ClincalTrials.gov on March 22, 2012; registration number NCT01566864
Quantitative analysis of cell types during growth and morphogenesis in Hydra
Tissue maceration was used to determine the absolute number and the distribution of cell types in Hydra. It was shown that the total number of cells per animal as well as the distribution of cells vary depending on temperature, feeding conditions, and state of growth. During head and foot regeneration and during budding the first detectable change in the cell distribution is an increase in the number of nerve cells at the site of morphogenesis. These results and the finding that nerve cells are most concentrated in the head region, diminishing in density down the body column, are discussed in relation to tissue polarity
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Heat and salt balances over the New England continental shelf, August 1996 to June 1997
Heat and salt balances over the New England shelf are examined using 10 month time
series of currents, temperature, and salinity from a four element moored array and surface
heat and freshwater fluxes from a meteorological buoy. A principal result is closure of
the heat budget to 10 W mâ2. The seasonal variation in depthâaverage temperature, from
14°C in September to 5°C in March, was primarily due to the seasonal variation in surface
heat flux and a heat loss in winter caused by alongâshelf advection of colder water from the
northeast. Conductivity sensor drifts precluded closing the salt balance on time scales of
months or longer. For time scales of days to weeks, depthâaverage temperature and salinity
variability were primarily due to advection. Advective heat and salt flux divergences were
strongest and most complex in winter, when there were large crossâshelf temperature
and salinity gradients at the site due to the shelfâslope front that separates cooler, fresher shelf
water from warmer, saltier slope water. Onshore flow of warm, salty slope water near
the bottom and offshore flow of cooler, fresher shelf water due to persistent eastward
(upwellingâfavorable) winds caused a temperature increase of nearly 3°C and a salinity
increase of 0.8 in winter. Alongâshelf barotropic tidal currents caused a temperature decrease
of 1.5°C and a salinity decrease of 0.7. Waveâdriven Stokes drift caused a temperature
increase of 0.5°C and a salinity increase of 0.4 from mid December to January when there
were large waves and large nearâsurface crossâshelf temperature and salinity gradients.Keywords: New England continental shelf, Heat and salt balancesKeywords: New England continental shelf, Heat and salt balance
Detectibility of Mixed Unburnt C+O in Type Ia Supernova Spectra
Motivated by recent 3-D calculations of the explosion of Type Ia supernova
via a pure deflagration we calculate the observed spectra at 15-25 days past
maximum light of a parameterized model which has a considerable fraction of
unburnt C+O in the central regions. Rather than attempting a self consistent
3-D calculation, which is beyond the scope of current computer codes, we modify
the composition structure of the 1-D deflagration model W7. In our exploratory
parameterized calculations, we find that a central concentration of C+O is not
ruled out by observations for the epochs we study. We briefly examine whether
nebular phase spectra could be incompatible with observations.Comment: 12 pages, 3 figures ApJ Letters, May 1, 2003, in pres
Ordered and disordered phospholipid domains coexist in membranes containing the calcium pump protein of sarcoplasmic reticulum.
Data are presented that lead to an alternative model for the organization and molecular dynamics of lipid molecules near the Ca2+-stimulated, Mg2+-dependent adenosinetriphosphatase (Ca2+-ATPase; ATP phosphohydrolase, EC 3.6.1.3) of sarcoplasmic reticulum. Measurements of the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene in progressively delipidated sarcoplasmic reticulum membranes have been quantitatively interpreted in terms of a layer of lipid of high anisotropy (the lipid annulus) coexisting with lipid layers of very low anisotropy. In addition, the Ca2+-ATPase has been reconstituted into pure 1,2-dipentadecanoyl 3-sn-phosphatidylcholine membranes over a range of lipid-to-protein ratios. High-sensitivity differential scanning calorimetry has demonstrated that roughly 30 lipid molecules per Ca2+-ATPase molecule (annular lipids) fail to undergo a calorimetrically detectable phase transition in the temperature range 4-44 degrees C. Roughly 100 lipid molecules beyond the annulus undergo a detectable phase transition at a temperature below the phase transition of pure lipid and with an enthalpy change [4.2 kcal/mol (1 kcal = 4.18 kJ)] about half that observed for pure lipid vesicles (7.7-7.8 kcal/mol). We propose that both the fluorometric and calorimetric data are consistent with a model in which a motionally inhibited lipid annulus is surrounded by a more extensive region of disrupted lipid packing order, which we have called the secondary lipid domain
Gravitational Waves from Core Collapse Supernovae
We present the gravitational wave signatures for a suite of axisymmetric core
collapse supernova models with progenitors masses between 12 and 25 solar
masses. These models are distinguished by the fact they explode and contain
essential physics (in particular, multi-frequency neutrino transport and
general relativity) needed for a more realistic description. Thus, we are able
to compute complete waveforms (i.e., through explosion) based on
non-parameterized, first-principles models. This is essential if the waveform
amplitudes and time scales are to be computed more precisely. Fourier
decomposition shows that the gravitational wave signals we predict should be
observable by AdvLIGO across the range of progenitors considered here. The
fundamental limitation of these models is in their imposition of axisymmetry.
Further progress will require counterpart three-dimensional models.Comment: 10 pages, 5 figure
Evidence for Asphericity in the Type IIn Supernova 1998S
We present optical spectropolarimetry obtained at the Keck-II 10-m telescope
on 1998 March 7 UT along with total flux spectra spanning the first 494 days
after discovery (1998 March 2 UT) of the peculiar type IIn supernova (SN)
1998S. The SN is found to exhibit a high degree of linear polarization,
implying significant asphericity for its continuum-scattering environment.
Prior to removal of the interstellar polarization, the polarization spectrum is
characterized by a flat continuum (at p ~ 2%) with distinct changes in
polarization associated with both the broad (FWZI >= 20,000 km/s) and narrow
(unresolved, FWHM < 300 km/s) line emission seen in the total flux spectrum.
When analyzed in terms of a polarized continuum with unpolarized broad-line
recombination emission, an intrinsic continuum polarization of p ~ 3% results
(the highest yet found for a SN), suggesting a global asphericity of >= 45%
from the oblate, electron-scattering dominated models of Hoflich (1991). The
smooth, blue continuum evident at early times is shown to be inconsistent with
a reddened, single-temperature blackbody, instead having a color temperature
that increases with decreasing wavelength. Broad emission-line profiles with
distinct blue and red peaks are seen in the total flux spectra at later times,
perhaps suggesting a disk-like or ring-like morphology for the dense (n_e ~
10^7 cm^{-3}) circumstellar medium. Implications of the circumstellar
scattering environment for the spectropolarimetry are discussed, as are the
effects of uncertain removal of interstellar polarization.Comment: 25 pages + 2 tables + 14 figures, Submitted to The Astrophysical
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