Trauma Early Mortality Prediction Tool (TEMPT) for assessing 28-day mortality.

Background:Prior mortality prediction models have incorporated severity of anatomic injury quantified by Abbreviated Injury Severity Score (AIS). Using a prospective cohort, a new score independent of AIS was developed using clinical and laboratory markers present on emergency department presentation to predict 28-day mortality. Methods:All patients (n=1427) enrolled in an ongoing prospective cohort study were included. Demographic, laboratory, and clinical data were recorded on admission. True random number generator technique divided the cohort into derivation (n=707) and validation groups (n=720). Using Youden indices, threshold values were selected for each potential predictor in the derivation cohort. Logistic regression was used to identify independent predictors. Significant variables were equally weighted to create a new mortality prediction score, the Trauma Early Mortality Prediction Tool (TEMPT) score. Area under the curve (AUC) was tested in the validation group. Pairwise comparison of Trauma Injury Severity Score (TRISS), Revised Trauma Score, Glasgow Coma Scale, and Injury Severity Score were tested against the TEMPT score. Results:There was no difference between baseline characteristics between derivation and validation groups. In multiple logistic regression, a model with presence of traumatic brain injury, increased age, elevated systolic blood pressure, decreased base excess, prolonged partial thromboplastin time, increased international normalized ratio (INR), and decreased temperature accurately predicted mortality at 28 days (AUC 0.93, 95% CI 0.90 to 0.96, P<0.001). In the validation cohort, this score, termed TEMPT, predicted 28-day mortality with an AUC 0.94 (95% CI 0.92 to 0.97). The TEMPT score preformed similarly to the revised TRISS score for severely injured patients and was highly predictive in those having mild to moderate injury. Discussion:TEMPT is a simple AIS-independent mortality prediction tool applicable very early following injury. TEMPT provides an AIS-independent score that could be used for early identification of those at risk of doing poorly following even minor injury. Level of evidence:Level II

What is the second parameter - The anomalous globular cluster NGC 7006

An infrared color-magnitude diagram for NGC 7006 and moderate dispersion digital optical spectra of eight of its members indicate a metal abundance of -1.5 dex with respect to the sun. However, the ratio of red to blue horizontal-branch stars is quite large and is what would be expected for a cluster of much higher metallicity. Molecular band strengths are determined for CO in four stars, and CH and CN in five stars, and it is found that none of these molecular bands are anomalously strong compared to the same molecular features in other globulars of similar metallicity but varying horizontal-branch type. This is contrary to the behavior predicted if the C, N, and O abundances are the 'second parameter' needed to explain anomalous horizontal-branch morphologies

The late-type stellar content of Magellanic Cloud clusters

New broad-band infrared photometric data have been obtained for 48 late-type giants in clusters in the Magellanic Clouds (MC). Visual spectrophotometry was obtained for a subset of these stars. These observations are combined with published data for MC cluster stars and then compared with similar data for MC field giants and with predictions of various evolutionary schemes for cool, luminous, carbon and oxygen rich stars. The MC cluster C stars are found to have a range in spectral energy distributions which is quite similar to that of MC field C stars. The luminosity function of the cluster C stars has a mean M_(bol) = —4.76 with a dispersion of ±0.36, also quite similar to the values for MC field C stars. However, the dispersion of the cluster C stars in M_K_0 at a given (J— K)_0 is between 2 and 3 times less than it is for the field C stars. This can arise if the present sample of clusters has a significantly smaller spread in age and/or metallicity than the progenitors of the field C stars. The LMC field contains M giants which are redder and more luminous than any so far found in LMC or SMC clusters. This is attributed to the presence in the LMC field of a significant population of stars which are younger and/or more metal rich than the stars in the cluster sample. Differences which are found to exist between the M star populations of the LMC and the SMC clusters are also attributed to age and/or metallicity effects. In all but one of the MC clusters which have both M and C stars, the faintest C star is brighter than the brightest M star. Such a “transition” luminosity appears to be correlated with the location of the cluster in the one-dimensional classification sequence of Searle, Wilkinson, and Bagnuolo, and it can be a useful criterion in the evaluation of theories of carbon star evolution. Finally, although the spectrophotometric data suggest that the LMC “halo-type” globular, NGC 1841 and 2257, have metallicities similar to one another and to that of M3, the locations of the NGC 1841 stars in a C-M diagram appear to be anomalous in the sense that its brightest stars have luminosities greater than the tips of giant branches of metal poor galactic globular clusters

Infrared photometry, bolometric luminosities, and effective temperatures for giant stars in 26 globular clusters

Infrared observations of 307 giant stars in 26 globular clusters are presented. The effects of H_2O absorption on the infrared colors are examined. The color-color correlations and color-magnitude diagrams, derived using an internally consistent set of distance moduli and reddenings, identify specific clusters with problematical reddenings or low quality optical data. The mean behavior of the color-color relationships is, in all cases, in good agreement with our earlier work

Globular cluster giant branches and the metallicity scale

Using the data base of Frogel, Persson, and Cohen and our earlier work, we derive characteristic parameters that describe the systematic behavior of the giants in each of 33 globular clusters. The globular cluster giant branches form a strictly homologous sequence in the H-R diagram, and their ordering correlates well with the metallicity scale published by Zinn. Nevertheless, when the giant branch parameters are used to define a metallicity ranking scheme, it appears that the Zinn abundance scale systematically underestimates the metallicity of clusters with exceptionally blue horizontal branches. The observed luminosities of the brightest giant in each cluster agree with the theoretical core helium flash luminosity; the small dispersion of these luminosities implies that at a given metallicity the intrinsic scatter in the absolute magnitude of horizontal-branch stars is less than 0.1 mag. The mean CO index increases as metallicity increases; analysis of the residuals from the mean relationships both of CO and of horizontal-branch type against metallicity imply that the CO abundance is unrelated to the second parameter problem. All metal-rich clusters with an adequate sample of stars show a spread in CO within each cluster comparable to that seen in 47 Tuc. Metal-poor clusters which exhibit a large star to star spread in CO are NGC 362, 2808, and 6656. The integrated light measurements of (V - K)_0 and CO published by Aaronson and colleagues correlate with the cluster parameters determined from measurements of individual stars in a manner that can be predicted from stellar evolutionary calculations for old populations. The integrated light of such old systems, at least from V to K, is therefore well understood

Photometric studies of composite stellar systems. IV - Infrared photometry of globular clusters in M31 and a comparison with early-type galaxies

The results of an infrared photometric investigation of 40 globular clusters in and around M31 are presented. The (V - K)_0 colors of the M31 globulars are tightly correlated with other broadband colors and with reddening-free metallicity parameters derived from optical spectrophotometry by Searle. Over a range of ˜1.2 mag in (V - K)_0, the scatter is consistent with observational error. Thus the 0.3-2.2 μm energy distributions are uniquely predicted by the metallicity and vice versa. A comparison of the (V - K)0 colors with those of galactic globulars allows an independent derivation of the metallicities of individual M31 globulars. The broad-band infrared data are compared with predictions from integrated light models based on the Ciardullo and Demarque isochrones. The agreement is quite good for models with an initial mass function of slope ≲ the Salpeter value independent of metallicity, thus ruling out the possibility that a late-type dwarf component is making a significant contribution to the infrared light. CO and H_2O indices measured for eight and seven of the clusters, respectively, give the same result. Early-type galaxies are seen to have much redder broad-band colors and stronger CO and H_2O indices than the most metal-rich M31 or galactic globular observed. Compared to the reddest globular clusters, at a given (U - V)_0 early-type galaxies are on average 0.3 mag redder in (V - K)_0. Although the stellar synthesis models reproduce cluster broad-band colors reasonably well, they do not reproduce the U - V/ V - K distribution of early-type galaxies. We propose that the early-type galaxies contain a population of cool luminous stars present neither in the clusters nor in the stellar synthesis models. One candidate for this population is a giant branch of stars considerably more metal rich than the Sun. More interesting is the possibility that there is a contribution to the integrated infrared light from asymptotic giant-branch stars above the first red giant tip. Such stars could be of intermediate age. The luminosity functions for the M31 and the galactic globulars are examined with the aid of models to investigate the possibility that metal-enhanced star formation or variations in the initial mass function can be detected in integrated light. Two appendices present new infrared data for a faint dE galaxy in the Virgo cluster, and a recalibration of the integrated light models presented by Aaron son et al.

Infrared photometry, bolometric magnitudes, and effective temperatures for giants in M3, M13, M92, and M67

Broad-band infrared J-, H-, and K-magnitudes and narrow-band CO and H_2O indices are presented for a selection of giants reaching 3 mag below the red-giant tip in the globular clusters M3, M13, and M92, and in the old open cluster M67. Comparison of these data with a calculated grid of model atmospheres gives the following results: (1) the models satisfactorily predict the broad-band colors; (2) V — K measurements accurate to ±0.1 mag can be used to give effective temperatures to ± 100 K independent of surface gravity or metal abundance for metal-poor stars; (3) there is disagreement with a previous (T_(eff), spectral type)-calibration based on DDO photometry. Empirical bolometric magnitudes are derived by integrating the observed energy distributions out to 2.2 /µm. The derived luminosities and effective temperatures are plotted in a H-R diagram and are compared with a set of evolutionary tracks for metal-poor stars due to Rood. The agreement is good. The CO index, which is sensitive primarily to luminosity and effective temperature for Population I giants, becomes sensitive to metal abundance for very metal-poor stars. The relative metal abundance of M3 and M13 derived from CO is reversed from that derived by some other methods. Some possible explanations are considered. Because of the importance of Rayleigh scattering in these cluster stars, B — V depends on surface gravity. Gravities determined from B — V colors are used to derive crude masses for the stars. These masses (~0.6 M_⊙) are roughly consistent with estimates of the turnoff mass. The CNO abundances are suggested as the second parameter affecting the color-magnitude diagrams of globular cluster

Luminosities and temperatures of the reddest stars in three LMC clusters

Infrared observations in the 1.2-2.2 µm region are presented for 12 of the reddest stars in the Large Magellanic Cloud (LMC) clusters NGC 1783,1846, and 1978. Seven of the stars, which are carbon stars, are photometrically indistinguishable from carbon stars in the general field of the LMC. Bolometric magnitudes and temperatures are derived from the infrared data. The average bolometric magnitude of the carbon stars is —4.9, which is about two magnitudes fainter than previously published values, but still high enough to require that these stars are asymptotic giant branch stars. The most luminous M-type stars in these clusters are warmer and perhaps more luminous than the giant branches of metal-rich Galactic globular clusters, in agreement with Hodge’s results based on UBV photometry. The location of the M-type stars may present some problems for recent giant branch model calculations

Infrared colors, CO band strengths, and physical parameters for giants in M71

Broad-band J, H, and K magnitudes and narrow-band CO and H_2O indices for 25 giant and horizontal-branch stars in the strong-lined globular cluster M71 are presented. These data are compared with similar data for M67 and for metal-poor globular clusters. In most photometric indices the M71 stars are intermediate between M67 and the metal-poor globulars, although the M71 giant branch extends to considerably cooler temperatures. Bolometric magnitudes and effective temperatures determined for the M71 stars also place this cluster between the other globulars and M67. A theoretical analysis of the CO indices indicates that M71 is metal deficient by 0.4 ( ± 0.2) dex in the mean with respect to field giants. The relationship between the CO indices and CN absorption strengths as determined from DDO photometry is as expected from empirically determined temperature dependences and theoretically determined abundance dependences

Infrared photometry of red giants in the globular cluster 47 Tucanae

Infrared broad-band JHK and intermediate-band CO and R2O photometry is presented for 64 stars in the globular cluster 47 Tucanae including the long period variables (LPV) V1-4. These data are combined with optical photometric data and compared with evolutionary tracks for giant branch (GB) stars, with models for asymptotic giant branch (AGB) stars, and with determinations of CN band strengths. The main results of this paper are as follows: 1. At a fixed luminosity, the 47 Tuc giants show negligible scatter in V-K or, equivalently, effective temperature. Except for the upper half-magnitude, the slope of the GB is similar to theoretical giant branch slopes of the appropriate metallicity. These two results set an upper limit of 0.2 M_⊙ to the mass lost by stars as they evolve from the level of the horizontal branch to within 0.5 mag of the GB tip. 2. Comparison of theoretical GB tracks with the observed giant branches of M92, Ml3, 47 Tuc, M7 1, and M67 show that shifts in T_(eff) are required to bring theory and observation into agreement. These shifts seem to be a function of [Fe/H] and are in the sense that the observed tracks lie progressively cooler than the theoretical tracks for higher metal abundance. This suggests that the ratio of the mixing length to the pressure scale height in the convective envelope may be a function of metallicity and/or stellar mass. 3. While an independent estimate of the metallicity of 47 Tuc cannot be made from the IR data alone, the close similarity in all observed parameters of the 47 Tuc stars and the M7 1 giants studied previously implies that the two clusters must have essentially the same metallicity. 4. At a given effective temperature, the CO absorption strengths of the 47 Tuc giants have a significant scatter. This scatter can be accounted for by an anticorrelation between the CO strengths and the CN strengths measured by Norris and Freeman. The origin of this anticorrelation is likely to be the effect of CN-blanketing in one of the filter band passes used to measure the CO strengths. 5. At mean light the four LPVs lie sufficiently above the tip of the giant branch that they must be AGB stars. Their luminosities, temperatures, and periods are in qualitative agreement with model predictions for such stars. The periodic behavior of these variables is similar to that of Galactic LPVs. 6. Stellar H_2O absorption in the band passes of the H and K filters is a strong influence on the J-H and H-K colors of some of the stars studied. Furthermore, the H_2O strengths observed in the four LPVs are greater than those in the non-LPV variables which, in turn, are greater than those in the nonvariables. Again, this is similar to the situation for cool Galactic variable and nonvariable giants