We present results of X-ray observations of a sample of 15 clusters selected via their imprint on the cosmic microwave background from the thermal Sunyaev-Zel'dovich (SZ) effect. These clusters are a ...subset of the first SZ-selected cluster catalog, obtained from observations of 178 deg2 of sky surveyed by the South Pole Telescope (SPT). Using X-ray observations with Chandra and XMM-Newton, we estimate the temperature, TX , and mass, Mg , of the intracluster medium within r 500 for each cluster. From these, we calculate YX = MgTX and estimate the total cluster mass using an M 500-YX scaling relation measured from previous X-ray studies. The integrated Comptonization, Y SZ, is derived from the SZ measurements, using additional information from the X-ray-measured gas density profiles and a universal temperature profile. We calculate scaling relations between the X-ray and SZ observables and find results generally consistent with other measurements and the expectations from simple self-similar behavior. Specifically, we fit a Y SZ-YX relation and find a normalization of 0.82 ? 0.07, marginally consistent with the predicted ratio of Y SZ/YX = 0.91 ? 0.01 that would be expected from the density and temperature models used in this work. Using the YX -derived mass estimates, we fit a Y SZ-M 500 relation and find a slope consistent with the self-similar expectation of Y SZM 5/3 with a normalization consistent with predictions from other X-ray studies. We find that the SZ mass estimates, derived from cosmological simulations of the SPT survey, are lower by a factor of 0.78 ? 0.06 relative to the X-ray mass estimates. This offset is at a level of 1.3 Delta *s when considering the ~15% systematic uncertainty for the simulation-based SZ masses. Overall, the X-ray measurements confirm that the scaling relations of the SZ-selected clusters are consistent with the properties of other X-ray-selected samples of massive clusters, even allowing for the broad redshift range (0.29 < z < 1.08) of the sample.
ABSTRACT We present the results of SPT-GMOS, a spectroscopic survey with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. The targets of SPT-GMOS are galaxy clusters identified in the ...SPT-SZ survey, a millimeter-wave survey of 2500 deg2 of the southern sky using the South Pole Telescope (SPT). Multi-object spectroscopic observations of 62 SPT-selected galaxy clusters were performed between 2011 January and 2015 December, yielding spectra with radial velocity measurements for 2595 sources. We identify 2243 of these sources as galaxies, and 352 as stars. Of the galaxies, we identify 1579 as members of SPT-SZ galaxy clusters. The primary goal of these observations was to obtain spectra of cluster member galaxies to estimate cluster redshifts and velocity dispersions. We describe the full spectroscopic data set and resulting data products, including galaxy redshifts, cluster redshifts, and velocity dispersions, and measurements of several well-known spectral indices for each galaxy: the equivalent width, W, of O ii λλ3727, 3729 and H-δ, and the 4000 break strength, D4000. We use the spectral indices to classify galaxies by spectral type (i.e., passive, post-starburst, star-forming), and we match the spectra against photometric catalogs to characterize spectroscopically observed cluster members as a function of brightness (relative to m ). Finally, we report several new measurements of redshifts for ten bright, strongly lensed background galaxies in the cores of eight galaxy clusters. Combining the SPT-GMOS data set with previous spectroscopic follow-up of SPT-SZ galaxy clusters results in spectroscopic measurements for >100 clusters, or ∼20% of the full SPT-SZ sample.
The nitrogen content of plant tissue is low relative to that of herbivores; as a consequence, dietary N can limit the growth and reproduction of herbivores and select for attributes that increase N ...acquisition. Bark beetles face a particularly severe challenge because the phloem that they consume is very low in nitrogen and phosphorus relative to their requirements. We quantified variation in the phloem concentrations of N and P in the host tree, Pinus taeda, and evaluated the following hypotheses regarding the role of symbiotic fungi in nutrient budgets of the herbivore Dendroctonus frontalis: D. frontalis experience variation in phloem nutrient concentrations across several spatial scales (H1); mycangial fungi enhance the diet of D. frontalis larvae by contributing to the acquisition of N and P (H2); Ophiostoma minus, an apparently antagonistic fungal symbiont, hinders D. frontalis larvae because it does not enhance nutrient concentrations of the phloem as much as mycangial fungi do (H3); and larvae of bark beetle species that lack mycangial fungi must consume more phloem to accomplish the same growth as larvae of D. frontalis (H4). In addition, we developed a general model for the N budgets of herbivorous insects that identifies the possible combinations of dietary and physiological parameters that can allow developmental success on low-nutrient diets. Spatial variation in phloem N was mostly at the level of trees within sites (a scale of meters) while P mostly varied among sites (a scale of kilometers). Trees with higher N content produced larger D. frontalis adults. Prior to infestation by beetles, phloem nutrient concentrations were very uniform within trees and very low relative to that of the bark beetles (N and P concentrations of D. frontalis adults were 28 and 8 times greater, respectively). During infestation, phloem nutrient concentrations increased overall and became highly variable within trees. Nitrogen concentrations increased from 0.40 ± 0.01% (mean ± 1 SE) in uninfested phloem to 0.86 ± 0.03% in the phloem surrounding successfully developing D. frontalis larvae, which are typically associated with one or two species of mutualistic mycangial fungi. Nitrogen concentrations were intermediate in other microhabitats within infested trees, including regions with no adult colonization, with failed larval development, or colonized by the antagonistic bluestain fungus O. minus. We parameterized a general nutrient-budget model for D. frontalis and a sympatric non-mycangial bark beetle, Ips grandicollis, which indicated that (1) mycangial fungi provide their benefits by concentrating dietary N for larvae; (2) O. minus may exert its antagonistic effects on D. frontalis larvae by failing to concentrate dietary N as much as mycangial fungi do; (3) non-mycangial bark beetles meet their N budgets through high consumption of unaltered, low-N phloem; and (4) larvae should easily meet their P requirements with any combination of consumption rate and development time that allows them to meet their N requirements. Alternative strategies for N acquisition may have general consequences for the population dynamics and community interactions of bark beetles.
Surveillance for hepatocellular carcinoma (HCC) with ultrasound in high-risk populations is generally believed to improve opportunities for treatment. However, tumors are still missed due to various ...factors. This study explores success versus failure of HCC surveillance.
This is a retrospective study of 1,125 HCC cases. Categories considered for successful detection were largest tumor ≤3.0 cm, single tumors ≤3.0 cm and ≤2.0 cm, and adherence to Milan criteria. Examined factors were age <60 years, gender, rural residence, body-mass index (BMI), hepatitis infection, smoking, diabetes, hyperlipidemia, cirrhosis, ascites, and Model for End-Stage Liver Disease <10.
HCC was found on surveillance in 257 patients with a mean tumor size of 3.17 cm; multiple tumors were seen in 28% of cases, bilateral tumors in 7.4%, and vascular invasion in 3.7%. Surveillance was successful in 61.5% of cases involving a largest tumor ≤3.0 cm, with BMI ≥35 negatively affecting detection (odds ratio OR 0.28,
=0.014) and cirrhosis positively affecting detection (OR 2.31,
=0.036). Ultrasound detected 19.1% of single tumors ≤2.0 cm with ascites improving the detection rate (OR 3.89,
=0.001). Finally, adherence to Milan criteria occurred in 75.1% of cases, revealing negative associations with diabetes (OR 0.48,
=0.044 and male gender (OR 0.49,
=0.08).
Although surveillance is recommended for HCC, not all surveillance ultrasound are ideal. Tumor detection can depend on gender, BMI, diabetes, cirrhosis, and ascites and is achieved in 19.1-75% of cases depending on the definition of success. Closer follow-up or additional imaging might be necessary for some patient subgroups.
Salicylate, the active component of aspirin, is known to induce tinnitus. However, the site and the mechanism of generation of tinnitus induced by salicylate remains unclear. Here, we developed a ...behavioral procedure to measure tinnitus in rats. The behavioral model was based on an active avoidance paradigm in which rats had to display a motor task (i.e., to jump on a climbing pole when hearing a sound). Giving salicylate led to a decrease in the percentage of correct responses (score) and a drastic increase in the number of false positive responses (i.e., animals execute the motor task during a silent period). Presentation of the sound at a constant perceptive level prevents decrease of the score, leading to the proposal that score is related to hearing performance. In contrast, the increase of false positive responses remained unchanged. In fact, animals behaved as if they hear a sound, indicating that they are experiencing tinnitus. Mefenamate in place of salicylate also increased the number of false positive responses, suggesting that salicylate-induced tinnitus is related to an inhibition of cyclooxygenase. One physiological basis of salicylate ototoxicity is likely to originate from altered arachidonic acid metabolism. Because arachidonic acid potentiates NMDA receptor currents, we tested the involvement of cochlear NMDA receptors in the occurrence of tinnitus. Application of NMDA antagonists into the perilymphatic fluids of the cochlea blocked the increase in pole-jumping behavior induced by salicylate, suggesting that salicylate induces tinnitus through activation of cochlear NMDA receptors.
SPT-CL J2040-4451-spectroscopically confirmed at z = 1.478-is the highest-redshift galaxy cluster yet discovered via the Sunyaev-Zel'dovich effect. SPT-CL J2040-4451 was a candidate galaxy cluster ...identified in the first 720 deg super(2) of the South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey, and has been confirmed in follow-up imaging and spectroscopy. From multi-object spectroscopy with Magellan-I/Baade+IMACS wemeasure spectroscopic redshifts for 15 cluster member galaxies, all of which have strong OII lambdalambda3727 emission. SPT-CL J2040-4451 has an SZ-measured mass of M sub(500,SZ) = 3.2 + or - 0.8 x 10 super(14) M sub(middot in circle) h super(-1) sub(70) , corresponding to M sub(200,SZ) = 5.8 + or - 1.4 x 10 super(14) M sub(middot in circle) h super(-1) sub(70). The velocity dispersion measured entirely from blue star-forming members is sigma sub(v) = 1500 + or - 520 km s super(-1). The prevalence of star-forming cluster members (galaxies with >1.5 M yr super(-1)) implies that this massive, high-redshift cluster is experiencing a phase of active star formation, and supports recent results showing a marked increase in star formation occurring in galaxy clusters at z gap 1.4. We also compute the probability of finding a cluster as rare as this in the SPT-SZ survey to be >99%, indicating that its discovery is not in tension with the concordance LambdaCDM cosmological model.
The galaxy cluster SPT-CL J0205-5829 currently has the highest spectroscopically confirmed redshift, z = 1.322, in the South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey. XMM-Newton observations ...measure a core-excluded temperature of TX = (ProQuest: Formulae and/or non-USASCII text omitted) keV producing a mass estimate that is consistent with the Sunyaev-Zel'dovich-derived mass. The combined SZ and X-ray mass estimate of M sub(500) = (4.8+ or -0.8) x (ProQuest: Formulae and/or non-USASCII text omitted) M sub(middot in circle) makes it the most massive known SZ-selected galaxy cluster at z > 1.2 and the second most massive at z > 1. Using optical and infrared observations, we find that the brightest galaxies in SPT-CL J0205-5829 are already well evolved by the time the universe was <5 Gyr old, with stellar population ages > ~3 Gyr, and low rates of star formation (<0.5 M sub(middot in circle) yr super(-1)). We find that, despite the high redshift and mass, the existence of SPT-CL J0205-5829 is not surprising given a flat LambdaCDM cosmology with Gaussian initial perturbations. The a priori chance of finding a cluster of similar rarity (or rarer) in a survey the size of the 2500 deg super(2) SPT-SZ survey is 69%.
Windthrow prediction models require data concerning stand characteristics and wind exposure. Geographic information system databases typically contain elevation, forest cover, and logging history ...layers, therefore attributes can be extracted for points distributed across a given landscape. Climate stations in forested areas are rare, but the wind regime at regularly spaced points can be estimated using mesoscale numerical weather prediction models such as MC2, MM5, and RAMS. More traditionally, wind exposure is estimated using topographic exposure indices. Using gridded and cutblock edge segment databases for areas of mountainous terrain in central British Columbia (McGregor) and on southwestern Vancouver Island (WIT), we examined the spatial variability of simulated wind speeds and topographic exposure indices, simple correlations between variables, and the utility of these variables in predicting clearcut edge windthrow. Approximately half of the spatial variability in topographic and wind variables occurred for points spaced within 4
km. After restricting the dataset to one point from every 16
km
2 panel, mean wind speed was found to be correlated with elevation (0.48, 0.86), but less well with topographic exposure indices (0.17–0.72). Correlations between local winds predicted during strong wind events and topographic exposure indices varied depending on the model used, ranging from non-significant to moderate (0.58). Concordance values for logistic regression models for predicting cutblock edge windthrow improved from 65.0 and 63.8 for base models with height and stand variables, to 70.2 and 68.2 with the addition of topographic exposure indices and extreme wind measures, for McGregor and WIT, respectively.
Windthrow hazard depends upon the interaction of numerous factors whose relative importance has yet to be assessed in the specific context of Eastern Canadian boreal forests. This paper presents ...results from three studies looking at their relative importance at different scales in the context of balsam fir stands. First, factors involved in a catastrophic windthrow are examined in order to assess their importance at a regional and local scale. Wind speeds were estimated from a numerical model and overlayed with windthrow, soil and stand maps. The two regions that were damaged presented many predisposing factors: high occurrence of shallow soils, of vulnerable species and of overmature stands. Moreover, both regions have been identified as high wind areas. No consistent effect of wind speed on windthrow could be demonstrated, but the increasing vulnerability of stands with increasing proportion of balsam fir in one region and increasing age in balsam fir stands in both regions was significant. In one region, shallow tills experienced more damage in comparison with deep tills but not in the other. The second study looks at windthrow in riparian buffer strips at a local level. It includes a wind tunnel study and a field monitoring in stands of similar species composition and age. Results have shown that windthrow after 7 years was very variable and did not differ with strip width or thinning in the strip. In fact, it was more closely related to locations exposed to stronger winds stressing the importance of wind exposure estimation. It also confirms the greater vulnerability of balsam fir. The last study addresses the identification of external indicators of mechanical weaknesses on individual trees. It involves dissections and winching of trees with and without defects. Results tend to indicate a reduction in resistance when cracks are present on balsam fir. These three studies provide some information to begin considering windthrow hazard in the management of balsam fir forests.
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