We derive the basic properties of seven Galactic open clusters containing Cepheids and construct their period-luminosity (P-L) relations. For our cluster main-sequence fitting we extend previous ...Hyades-based empirical color-temperature corrections to hotter stars using the Pleiades as a template. We use BV I sub(c)JHK sub(s) data to test the reddening law and include metallicity effects to perform a more comprehensive study for our clusters than prior efforts. The ratio of total to selective extinction Rv that we derive is consistent with expectations. Assuming the LMC P-L slopes, we find (M sub(v)) = -3.93 plus or minus 0.07 (statistical) plus or minus 0.14 (systematic) for 10 day period Cepheids, which is generally fainter than those in previous studies. Our results are consistent with recent HST and Hipparcos parallax studies when using the Wesenheit magnitudes W(VI). Uncertainties in reddening and metallicity are the major remaining sources of error in the V-band P-L relation, but a higher precision could be obtained with deeper optical and near-infrared cluster photometry. We derive distances to NGC 4258, the LMC, and M33 of(m - M) sub(0) = 29.28 plus or minus 0.10, 18.34 plus or minus 0.06, and 24.55 plus or minus 0.28, respectively, with an additional systematic error of 0.16 mag in the P-L relations. The distance to NGC 4258 is in good agreement with the geometric distance derived from water masers Delta (m - M) sub(0) = 0.01 plus or minus 0.24, our value for M33 is less consistent with the distance from an eclipsing binary Delta (m - M) sub(0) = 0.37 plus or minus 0.34, and our LMC distance is moderately shorter than the adopted distance in the HST Key Project, which formally implies an increase in the Hubble constant of 7% plus or minus 8%.
In a single-center study published more than a decade ago involving patients presenting to the emergency department with severe sepsis and septic shock, mortality was markedly lower among those who ...were treated according to a 6-hour protocol of early goal-directed therapy (EGDT), in which intravenous fluids, vasopressors, inotropes, and blood transfusions were adjusted to reach central hemodynamic targets, than among those receiving usual care. We conducted a trial to determine whether these findings were generalizable and whether all aspects of the protocol were necessary.
In 31 emergency departments in the United States, we randomly assigned patients with septic shock to one of three groups for 6 hours of resuscitation: protocol-based EGDT; protocol-based standard therapy that did not require the placement of a central venous catheter, administration of inotropes, or blood transfusions; or usual care. The primary end point was 60-day in-hospital mortality. We tested sequentially whether protocol-based care (EGDT and standard-therapy groups combined) was superior to usual care and whether protocol-based EGDT was superior to protocol-based standard therapy. Secondary outcomes included longer-term mortality and the need for organ support.
We enrolled 1341 patients, of whom 439 were randomly assigned to protocol-based EGDT, 446 to protocol-based standard therapy, and 456 to usual care. Resuscitation strategies differed significantly with respect to the monitoring of central venous pressure and oxygen and the use of intravenous fluids, vasopressors, inotropes, and blood transfusions. By 60 days, there were 92 deaths in the protocol-based EGDT group (21.0%), 81 in the protocol-based standard-therapy group (18.2%), and 86 in the usual-care group (18.9%) (relative risk with protocol-based therapy vs. usual care, 1.04; 95% confidence interval CI, 0.82 to 1.31; P=0.83; relative risk with protocol-based EGDT vs. protocol-based standard therapy, 1.15; 95% CI, 0.88 to 1.51; P=0.31). There were no significant differences in 90-day mortality, 1-year mortality, or the need for organ support.
In a multicenter trial conducted in the tertiary care setting, protocol-based resuscitation of patients in whom septic shock was diagnosed in the emergency department did not improve outcomes. (Funded by the National Institute of General Medical Sciences; ProCESS ClinicalTrials.gov number, NCT00510835.).
Mergers of Close Primordial Binaries Andronov, N; Pinsonneault, M. H; Terndrup, D. M
The Astrophysical journal,
08/2006, Volume:
646, Issue:
2
Journal Article
We continue our series of papers on open cluster distances with a critical assessment of the accuracy of main-sequence fitting using isochrones that employ empirical corrections to the ...color-temperature relations. We use four nearby open clusters with multicolor photometry and accurate metallicities and present a new metallicity for Praesepe (Fe/H = +0.11 c 0.03) from high-resolution spectra. The internal precision of distance estimates is about a factor of 5 better than the case without the color calibrations. After taking into account all major systematic errors, we obtain distances accurate to about 2%-3% when there exists a good metallicity estimate. Metallicities accurate to better than 0.1 dex may be obtained from BVI sub(C)K sub(s) photometry alone. We also derive a helium abundance for the Pleiades of Y= 0.279 c 0.015, which is equal within the errors to the Sun's initial helium abundance and that of the Hyades. Our best estimates of distances are (m - M) sub(0) = 6.33 c 0.04, 8.03 c 0.04, and 9.61 c 0.03 to Praesepe, NGC 2516, and M67, respectively. Our Pleiades distance at the spectroscopic metallicity, (m - M) sub(0) = 5.66 c 0.01 (internal) c 0.05(systematic), is in excellent agreement with several geometric distance measurements. We have made calibrated isochrones for -0.3 , Fe/H , +0.2 available online.
In response to the proposed high-helium content stars as an explanation for the double main sequence observed in omega Centauri, we investigated the consequences of such stars elsewhere on the ...color-magnitude diagram. We concentrated on the horizontal branch, where the effects of high helium are expected to show themselves more clearly. In the process we developed a procedure for comparing the mass loss suffered by differing stellar populations in a physically motivated manner. High-helium stars in the numbers proposed seem absent from the horizontal branch of omega Cen unless their mass-loss history is very different from that of the majority metal-poor stars. It is possible to generate a double main sequence with existing omega Cen stars via accretion of helium-rich pollution consistent with the latest AGB ejecta theoretical yields and such polluted stars are consistent with the observed HB morphology of omega Cen. Polluted models are consistent with observed merging of the main sequences as opposed to our models of helium-rich stars. Using the(B - R)/(B + V + R) statistic, we find that the high-helium bMS stars require an age difference compared to the rMS stars that is too great, whereas the pollution scenario stars have no such conflict for inferred omega Cen mass losses.
We continue our program of single-site observations of pulsating subdwarf B (sdB) stars and present the results of extensive time series photometry of HS 0039+4302 and 0444+0458. Both were observed ...at MDM Observatory during the fall of 2005. We extend the number of known frequencies for HS 0039+4302 from four to 14 and discover one additional frequency for HS 0444+0458, bringing the total to three. We perform standard tests to search for multiplet structure, measure amplitude variations and examine the frequency density to constrain the mode degree ℓ. Including the two stars in this paper, 23 pulsating sdB stars have received follow-up observations designed to decipher their pulsation spectra. It is worth an examination of what has been detected. We compare and contrast the frequency content in terms of richness and range and the amplitudes with regard to variability and diversity. We use this information to examine observational correlations with the proposed κ pulsation mechanism as well as alternative theories.
Abstract In the United States, an increasing number of law enforcement agencies have employed the use of TASER® (TASER International Inc., Scottsdale, AZ) devices to temporarily immobilize violent ...subjects. There are reports in the lay press of adverse outcomes occurring in patients on whom TASER® devices have been deployed. Rhabdomyolysis has been associated with patients sustaining a TASER® shock, with a 1% incidence rate in subjects subdued with earlier versions of the device and then brought to the Emergency Department (ED). We present the cases of 2 patients who were seen in our ED after exhibiting violent behavior and receiving TASER® shocks. Both were hospitalized and received treatment for mild rhabdomyolysis. Both patients had multiple other characteristics that have been found to have an association with the development of rhabdomyolysis, in addition to the shocks they received. A review and discussion of the available medical literature on the subject follows, describing several complications that have been documented in patients after receiving TASER® shocks. Although a direct link between the TASER® and the reported adverse effects has not been established, patients who undergo restraint via this device frequently have pre-existing conditions or have exhibited behavior that places them at risk for the development of those effects. Such awareness of these possible complications is vital because the evaluation and management of patients developing adverse effects after these events will commonly occur in the ED.
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