Aims. The aim of this work is twofold: first, to assess whether the population of elliptical galaxies in cluster at z~ 1.3 differs from the population in the field and whether their intrinsic ...structure depends on the environment where they belong; second, to constrain their properties 9 Gyr back in time through the study of their scaling relations. Methods. We compared a sample of 56 cluster elliptical galaxies selected from three clusters at 1.2 <z< 1.4 with elliptical galaxies selected at comparable redshift in the GOODS-South field (~30), in the COSMOS area (~180), and in the CANDELS fields (~220). To single out the environmental effects, we selected cluster and field elliptical galaxies according to their morphology. We compared physical and structural parameters of galaxies in the two environments and we derived the relationships between effective radius, surface brightness, stellar mass, and stellar mass density capital sigma Re within the effective radius and central mass density capital sigma sub(1 kpc), within 1 kpc radius. Results. We find that the structure and the properties of cluster elliptical galaxies do not differ from those in the field: they are characterized by the same structural parameters at fixed mass and they follow the same scaling relations. On the other hand, the population of field elliptical galaxies at z~ 1.3 shows a significant lack of massive (M sub(*)> 2 x 10 super(11)M sub(middot in circle)) and large (R sub(e)> 4-5 kpc) elliptical galaxies with respect to the cluster. Nonetheless, at M sub(*)< 2 x 10 super(11)M sub(middot in circle), the two populations are similar. The size-mass relation of cluster and field ellipticals at z~ 1.3 clearly defines two different regimes, above and below a transition mass m sub(t)Asymptotically = to 2-3 x 10 super(10)M sub(middot in circle): at lower masses the relation is nearly flat (R sub(e)is proportional to Mu sub(*) super(-0.1+ or -0.2)), the mean radius is nearly constant at ~1 kpc and, consequenly, capital sigma ReAsymptotically = to capital sigma sub(1 kpc) while, at larger masses, the relation is R sub(e)is proportional to Mu sub(*) super(0.64+ or -0.09). The transition mass marks the mass at which galaxies reach the maximum stellar mass density. Also the capital sigma sub(1 kpc)-mass relation follows two different regimes, above and below the transition mass ( capital sigma sub(1 kpc)is proportional to Mu sub(*) sub(1.07<mt) super(0.64>mt)) defining a transition mass density capital sigma sub(1 kpc)Asymptotically = to 2-3 x 10 super(3)M sub(middot in circle) pc super(-2). The effective stellar mass density capital sigma Re does not correlate with mass; dense/compact galaxies can be assembled over a wide mass regime, independently of the environment. The central stellar mass density, capital sigma sub(1 kpc), besides being correlated with the mass, is correlated to the age of the stellar population: the higher the central stellar mass density, the higher the mass, the older the age of the stellar population. Conclusions. While we found some evidence of environmental effects on the elliptical galaxies as a population, we did not find differences between the intrinsic properties of cluster and field elliptical galaxies at comparable redshift. The structure and the shaping of elliptical galaxies at z~ 1.3 do not depend on the environment. However, a dense environment seems to be more efficient in assembling high-mass large ellipticals, much rarer in the field at this redshift. The correlation found between the central stellar mass density and the age of the galaxies beside the mass shows the close connection of the central regions to the main phases of mass growth.
Distributed Temperature Sensing (DTS) technology enables downhole temperature monitoring to study hydrogeological processes at unprecedentedly high frequency and spatial resolution. DTS has been ...widely applied in passive mode in site investigations of groundwater flow, in‐well flow, and subsurface thermal property estimation. However, recent years have seen the further development of the use of DTS in an active mode (A‐DTS) for which heat sources are deployed. A suite of recent studies using A‐DTS downhole in hydrogeological investigations illustrate the wide range of different approaches and creativity in designing methodologies. The purpose of this review is to outline and discuss the various applications and limitations of DTS in downhole investigations for hydrogeological conditions and aquifer geological properties. To this end, we first review examples where passive DTS has been used to study hydrogeology via downhole applications. Secondly, we discuss and categorize current A‐DTS borehole methods into three types. These are thermal advection tests, hybrid cable flow logging, and heat pulse tests. We explore the various options with regards to cable installation, heating approach, duration, and spatial extent in order to improve their applicability in a range of settings. These determine the extent to which each method is sensitive to thermal properties, vertical in‐well flow, or natural gradient flow. Our review confirms that the application of DTS has significant advantages over discrete point temperature measurements, particularly in deep wells, and highlights the potential for further method developments in conjunction with other emerging hydrogeophysical tools.
Key Points
Distributed Temperature Sensing in subsurface applications allows the monitoring subsurface hydrology in unprecedented spatiotemporal detail
The specific limitations of DTS measurements need to be taken into account in the design of field installations
The application of DTS in subsurface hydrology is still under development
Aims. We investigate the stellar mass assembly history of ultramassive (M⋆ ≳ 1011M⊙) dense (Σ = M⋆/2πRe2> 2500M⊙ pc-2) early-type galaxies (ETGs, elliptical and spheroidal galaxies) selected on basis ...of visual classification over the last 9 Gyr. Methods. We traced the evolution of the comoving number density ρ of ultramassive dense ETGs and compared their structural (effective radius Re and stellar mass M⋆) and dynamical (velocity dispersion σe) parameters over the redshift range 0 < z < 1.6. We derived the number density ρ at 1.6 <z< 1 from the MUNICS and GOODS-South surveys, while we took advantage of the COSMOS spectroscopic survey to probe the intermediate redshift range 0.2−1.0. We derived the number density of ultramassive dense local ETGs from the SDSS sample taking all of the selection bias affecting the spectroscopic sample into account. To compare the dynamical and structural parameters, we collected a sample of 11 ultramassive dense ETGs at 1.2 < z < 1.6 for which velocity dispersion measurements are available. For four of these ETGs (plus one at z = 1.91), we present previously unpublished estimates of velocity dispersion, based on optical VLT-FORS2 spectra. We probe the intermediate redshift range (0.2 ≲ z ≲ 0.9) and the local Universe with different ETGs samples. Results. We find that the comoving number density of ultramassive dense ETGs evolves with z as ρ(z) ∝ (1 + z)0.3 ± 0.8 implying a decrease of ~25% of the population of ultramassive dense ETGs since z = 1.6. By comparing the structural and dynamical properties of high-z ultramassive dense ETGs over the range 0 ≲ z < 1.6 in the Re, M⋆, σe plane, we find that all of the ETGs of the high-z sample have counterparts with similar properties in the local Universe. This implies either that the majority (~70%) of ultramassive dense ETGs already completed the assembly and shaping at ⟨ z ⟩ = 1.4, or that, if a significant portion of dense ETGs evolves in size, new ultramassive dense ETGs must form at z < 1.5 to maintain their number density at almost constant. The difficulty in identify good progenitors for these new dense ETGs at z ≲ 1.5 and the stellar populations properties of local ultramassive dense ETGs point towards the first hypothesis. In this case, the ultramassive dense galaxies missing in the local Universe could have joined, in the last 9 Gyr, the so colled non-dense ETGs population through minor mergers, thus contributing to mean size growth. In any case, the comparison between their number density and the number density of the whole population of ultramassive ETGs relegates their contribution to the mean size evolution to a secondary process.
We present the first estimate of age, stellar metallicity and chemical abundance ratios, for an individual early-type galaxy at high-redshift (z = 1.426) in the COSMOS (Cosmological Evolution Survey) ...field. Our analysis is based on observations obtained with the X-Shooter instrument at the Very Large Telescope (VLT), which cover the visual and near-infrared spectrum at high (R > 5000) spectral resolution. We measure the values of several spectral absorptions tracing chemical species, in particular magnesium and iron, besides determining the age-sensitive D4000 break. We compare the measured indices to stellar population models, finding good agreement. We find that our target is an old (t > 3 Gyr), high-metallicity (Z/H > 0.5) galaxy which formed its stars at z
form >5 within a short time-scale ∼0.1 Gyr, as testified by the strong α/Fe ratio (>0.4), and has passively evolved in the first >3–4 Gyr of its life. We have verified that this result is robust against the choice and number of fitted spectral features, and stellar population model. The result of an old age and high-metallicity has important implications for galaxy formation and evolution confirming an early and rapid formation of the most massive galaxies in the Universe.
Aims. This paper aims at understanding whether the normalization of the stellar initial mass function (IMF) of massive galaxies varies with cosmic time and/or with mean stellar mass density Σ = ...M⋆/(2πRe2). Methods. We have tackled this question by taking advantage of a spectroscopic sample of 18 dense (Σ > 2500 M⊙ pc-2) massive early-type galaxies (ETGs) that we collected at 1.2 ≲ z ≲ 1.6. Each galaxy in the sample was selected in order to have available: i) a high-resolution deep HST-F160W image to visually classify it as an ETG; ii) an accurate velocity dispersion estimate; iii) stellar mass derived through the fit of multiband photometry; and iv) structural parameters (i.e. effective radius Re and Sersic index n) derived in the F160W-band. We have constrained the mass-normalization of the IMF of dense high-z ETGs by comparing the true stellar masses of the ETGs in the sample (Mtrue) derived through virial theorem, hence IMF independent, with those inferred through the fit of the photometry which assume a reference IMF (Mref). Adopting the virial estimator as proxy of the true stellar mass, we have implicitly assumed that these systems have zero dark matter. However, recent dynamical analysis of massive local ETGs have shown that the dark matter fraction within Re in dense ETGs is negligible (<5−10%) and simulations of dissipationless mergers of spheroidal galaxies have shown that this fraction decreases going back with time. Accurate dynamical models of local ETGs performed by the ATLAS3D team have shown that the virial estimator is prone to underestimating or overestimating the total masses. We have considered this, and based on the results of ATLAS3D we have shown that for dense ETGs the mean value of total masses derived through the virial estimator with a non-homologous virial coefficient and Sersic-Re are perfectly in agreement with the mean value of those derived through more sophisticated dynamical models, although, of course, the estimates show higher uncertainties. Results. Tracing the variation of the parameter Γ = Mtrue/Mref with velocity dispersion σe, we have found that, on average, dense ETGs at ⟨ z ⟩ = 1.4 follow the same IMF-σe trend of typical local ETGs, but with a lower mass-normalization. The observed lower normalization could be evidence of i) an evolution of the IMF with time or ii) a correlation with Σ. To discriminate between the two possibilities, we have compared the IMF-σe trend that we have found for high-z dense ETGs with that of local ETGs with similar mean stellar mass density and velocity dispersion and we have found that the IMF of massive dense ETGs does not depend on redshift. The similarity between the IMF-σe trends observed both in dense high-z and low-z ETGs over 9 Gyr of evolution and their lower mass-normalization with respect to the mean value of local ETGs suggests that, independently of formation redshift, the physical conditions which characterized the formation of a dense spheroid on average lead to a mass spectrum of newly formed stars with a higher ratio of high- to low-mass stars with respect to the IMF of normal local ETGs. In the direction of our findings, recent hydrodynamical simulations show that the higher star-formation rate that should have characterized the early stage of star formation of dense ETGs is expected to inhibit the formation of low-mass stars. Hence, compact ETGs should have higher ratio of high- to low-mass stars than normal spheroids, as we observe.
To determine the relationship between recorded head accelerations and impact locations and acute clinical outcome of symptomatology, neuropsychological, and postural stability tests after cerebral ...concussion in Division I collegiate football players.
A prospective field study was used in which accelerometers were embedded in the football helmets of 88 collegiate football players. Linear and rotational accelerations of all head impacts sustained over the course of 2004 to 2006 National Collegiate Athletic Association football seasons were collected in real-time. Change scores were calculated on clinical measures from the players' preseason baseline to postinjury (within 48 h) and regressed against the recorded linear and rotational accelerations of the head at the time of the concussion.
Thirteen concussions were recorded ranging in impact magnitudes of 60.51 to 168.71 g. Linear regression showed no significant relationships between impact magnitude (linear or rotational acceleration) or impact location and change scores for symptom severity, postural stability, or neurocognitive function (P > 0.05).
Our findings suggest that football players are concussed by impacts to the head that occur at a wide range of magnitudes and that clinical measures of acute symptom severity, postural stability, and neuropsychological function all appear to be largely independent of impact magnitude and location. Because of the varying magnitudes and locations of impacts resulting in concussion as well as other factors such as the frequency of subconcussive impacts and number of previous concussions, it may be difficult to establish a threshold for concussive injury that can be applied to all football players.
Aims. There are two aims to our analysis. On the one hand we are interested in addressing whether a sample of morphologically selected early-type galaxies (ETGs) differs from a sample of passive ...galaxies in terms of galaxy statistics. On the other hand we study how the relative abundance of galaxies, the number density, and, the stellar mass density for different morphological types change over the redshift range 0.6 ≤ z ≤ 2.5. Methods. From the 1302 galaxies brighter than Ks(AB) = 22 selected from the GOODS-MUSIC catalogue, we classified the ETGs, i.e. elliptical (E) and spheroidal galaxies (E/S0), on the basis of their morphology and the passive galaxies on the basis of their specific star formation rate (sSFR ≤ 10-11 yr-1). Since the definition of a passive galaxy depends on the model parameters assumed to fit the spectral energy distribution of the galaxy, in addition to the assumed sSFR threshold, we probed the dependence of this definition and selection on the stellar initial mass function (IMF). Results. We find that spheroidal galaxies cannot be distinguished from the other morphological classes on the basis of their low star formation rate, irrespective of the IMF adopted in the models. In particular, we find that a large fraction of passive galaxies (>30%) are disc-shaped objects and that the passive selection misses a significant fraction (~26%) of morphologically classified ETGs. Using the sample of 1302 galaxies morphologically classified into spheroidal galaxies (ETGs) and non-spheroidal galaxies (LTGs), we find that the fraction of these two morphological classes is constant over the redshift range 0.6 ≤ z ≤ 2.5, being 20–30% the fraction of ETGs and 70–80% the fraction of LTGs. However, at z < 1 these fractions change among the population of the most massive (M∗ ≥ 1011 M⊙) galaxies, with the fraction of massive ETGs rising up to 40% and the fraction of massive LTGs decreasing to 60%. Parallel to this trend, we find that the number density and the stellar mass density of the whole population of massive galaxies increase by almost a factor of ~10 between 0.6 ≤ z ≤ 2.5, with a faster increase of these densities for the ETGs than for the LTGs. Finally, we find that the number density of the highest-mass galaxies both ETGs and LTGs (M∗> 3−4 × 1011 M⊙) does not increase from z ~ 2.5, contrary to the lower mass galaxies. This suggests that the most massive galaxies formed at z> 2.5−3 and that the assembly of such high-mass galaxies is not effective at lower redshift.
Aims. The aim of this work is twofold: first, to assess whether the population of elliptical galaxies in cluster at z ~ 1.3 differs from the population in the field and whether their intrinsic ...structure depends on the environment where they belong; second, to constrain their properties 9 Gyr back in time through the study of their scaling relations. Methods. We compared a sample of 56 cluster elliptical galaxies selected from three clusters at 1.2 <z < 1.4 with elliptical galaxies selected at comparable redshift in the GOODS-South field (~30), in the COSMOS area (~180), and in the CANDELS fields (~220). To single out the environmental effects, we selected cluster and field elliptical galaxies according to their morphology. We compared physical and structural parameters of galaxies in the two environments and we derived the relationships between effective radius, surface brightness, stellar mass, and stellar mass density ΣRe within the effective radius and central mass density Σ1 kpc, within 1 kpc radius. Results. We find that the structure and the properties of cluster elliptical galaxies do not differ from those in the field: they are characterized by the same structural parameters at fixed mass and they follow the same scaling relations. On the other hand, the population of field elliptical galaxies at z ~ 1.3 shows a significant lack of massive (ℳ∗> 2 × 1011M⊙) and large (Re> 4−5 kpc) elliptical galaxies with respect to the cluster. Nonetheless, at ℳ∗< 2 × 1011M⊙, the two populations are similar. The size-mass relation of cluster and field ellipticals at z ~ 1.3 clearly defines two different regimes, above and below a transition mass mt ≃ 2−3 × 1010M⊙: at lower masses the relation is nearly flat (Re ∝ Μ*-0.1±0.2), the mean radius is nearly constant at ~1 kpc and, consequenly, ΣRe ≃ Σ1 kpc while, at larger masses, the relation is Re ∝ Μ*0.64±0.09. The transition mass marks the mass at which galaxies reach the maximum stellar mass density. Also the Σ1 kpc-mass relation follows two different regimes, above and below the transition mass (Σ1 kpc ∝ Μ*1.07mt) defining a transition mass density Σ1 kpc ≃ 2−3 × 103M⊙ pc-2. The effective stellar mass density ΣRe does not correlate with mass; dense/compact galaxies can be assembled over a wide mass regime, independently of the environment. The central stellar mass density, Σ1 kpc, besides being correlated with the mass, is correlated to the age of the stellar population: the higher the central stellar mass density, the higher the mass, the older the age of the stellar population. Conclusions. While we found some evidence of environmental effects on the elliptical galaxies as a population, we did not find differences between the intrinsic properties of cluster and field elliptical galaxies at comparable redshift. The structure and the shaping of elliptical galaxies at z ~ 1.3 do not depend on the environment. However, a dense environment seems to be more efficient in assembling high-mass large ellipticals, much rarer in the field at this redshift. The correlation found between the central stellar mass density and the age of the galaxies beside the mass shows the close connection of the central regions to the main phases of mass growth.
To evaluate endocrine activity in terms of ovarian function suppression (OFS) of degarelix (a gonadotropin-releasing hormone GnRH antagonist) versus triptorelin (a GnRH agonist) in premenopausal ...patients receiving letrozole as neoadjuvant endocrine therapy for breast cancer.
Premenopausal women with stage cT2 to 4b, any N, M0; estrogen receptor and progesterone receptor greater than 50%; human epidermal growth factor receptor 2-negative breast cancer were randomly assigned to triptorelin 3.75 mg administered intramuscularly on day 1 of every cycle or degarelix 240 mg administered subcutaneously (SC) on day 1 of cycle 1 then 80 mg SC on day 1 of cycles 2 through 6, both with letrozole 2.5 mg/day for six 28-day cycles. Surgery was performed 2 to 3 weeks after the last injection. Serum was collected at baseline, after 24 and 72 hours, at 7 and 14 days, and then before injections on cycles 2 through 6. The primary end point was time to optimal OFS (time from the first injection to first assessment of centrally assessed estradiol level ≤ 2.72 pg/mL ≤ 10 pmol/L during neoadjuvant therapy). The trial had 90% power to detect a difference using a log-rank test with a two-sided α of .05. Secondary end points included response, tolerability, and patient-reported endocrine symptoms.
Between February 2014 and January 2017, 51 patients were enrolled (n = 26 received triptorelin plus letrozole; n = 25 received degarelix plus letrozole). Time to optimal OFS was three times faster for patients assigned to degarelix and letrozole than to triptorelin and letrozole (median, 3 v 14 days; hazard ratio, 3.05; 95% CI, 1.65 to 5.65; P < .001). Furthermore, OFS was maintained during subsequent cycles for all patients assigned to receive degarelix and letrozole, whereas 15.4% of patients assigned to receive triptorelin and letrozole had suboptimal OFS after cycle 1 (six events during 127 measurements). Adverse events as a result of both degarelix plus letrozole and triptorelin plus letrozole were as expected.
In premenopausal women receiving letrozole for neoadjuvant endocrine therapy, OFS was achieved more quickly and maintained more effectively with degarelix than with triptorelin.
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