3,801 research outputs found
A Map of the Universe
We have produced a new conformal map of the universe illustrating recent
discoveries, ranging from Kuiper belt objects in the Solar system, to the
galaxies and quasars from the Sloan Digital Sky Survey. This map projection,
based on the logarithm map of the complex plane, preserves shapes locally, and
yet is able to display the entire range of astronomical scales from the Earth's
neighborhood to the cosmic microwave background. The conformal nature of the
projection, preserving shapes locally, may be of particular use for analyzing
large scale structure. Prominent in the map is a Sloan Great Wall of galaxies
1.37 billion light years long, 80% longer than the Great Wall discovered by
Geller and Huchra and therefore the largest observed structure in the universe.Comment: Figure 8, and additional material accessible on the web at:
http://www.astro.princeton.edu/~mjuric/universe
Interpretation of porosity and LWD resistivity from the Nankai accretionary wedge in light of clay physicochemical properties: Evidence for erosion and local overpressuring
International audienceIn this study, we used porosity to assess the compaction state of the Nankai accretionary wedge sediments and any implications for stress and pore pressure. However, hydrous minerals affect porosity measurements, and accounting for them is essential toward defining the interstitial porosity truly representative of the compaction state. The water content of sediments was measured in core samples and estimated from logging data using a resistivity model for shale. We used the cation exchange capacity to correct the porosity data for the amount of water bound to clay minerals and to correct the porosity estimates for the surface conductivity of hydrous minerals. The results indicate that several apparent porosity anomalies are significantly reduced by this correction, implying that they are in part artifacts from hydrous minerals. The correction also improves the fit of porosity estimated from logging-while-drilling (LWD) resistivity data to porosity measured on cores. Low overall porosities at the toe of the accretionary wedge and in the splay fault area are best explained by erosion, and we estimated the quantity of sediments eroded within the splay fault area by comparing porosity-effective stress relationships of the sediments to a reference curve. Additionally, a comparison of LWD data with core data (resistivity and P wave velocity) obtained at Site C0001 landward of the mega-splay fault area, suggested a contribution from the fracture porosity to in situ properties on the formation
A guide for managing patients with stage I NSCLC: Deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 2: Systematic review of evidence regarding resection extent in generally healthy patients
Background: Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options (lobectomy, segmentectomy, wedge, stereotactic body radiotherapy, thermal ablation), weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.
Methods: A PubMed systematic review from 2000-2021 of outcomes after lobectomy, segmentectomy and wedge resection in generally healthy patients is the focus of this paper. Evidence was abstracted from randomized trials and non-randomized comparisons with at least some adjustment for confounders. The analysis involved careful assessment, including characteristics of patients, settings, residual confounding etc. to expose degrees of uncertainty and applicability to individual patients. Evidence is summarized that provides an at-a-glance overall impression as well as the ability to delve into layers of details of the patients, settings and treatments involved.
Results: In healthy patients there is no short-term benefit to sublobar resection
Conclusions: A systematic, comprehensive summary of evidence regarding resection extent in healthy patients with attention to aspects of applicability, uncertainty and effect modifiers provides a foundation on which to build a framework for individualized clinical decision-making
A guide for managing patients with stage I NSCLC: Deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 3: Systematic review of evidence regarding surgery in compromised patients or specific tumors
Background: Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options [lobectomy, segmentectomy, wedge, stereotactic body radiotherapy (SBRT), thermal ablation], weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.
Methods: A PubMed systematic review from 2000-2021 of outcomes after lobectomy, segmentectomy and wedge resection in older patients, patients with limited pulmonary reserve and favorable tumors is the focus of this paper. Evidence was abstracted from randomized trials and non-randomized comparisons (NRCs) with adjustment for confounders. The analysis involved careful assessment, including characteristics of patients, settings, residual confounding etc. to expose degrees of uncertainty and applicability to individual patients. Evidence is summarized that provides an at-a-glance overall impression as well as the ability to delve into layers of details of the patients, settings and treatments involved.
Results: In older patients, perioperative mortality is minimally altered by resection extent and only slightly affected by increasing age; sublobar resection may slightly decrease morbidity. Long-term outcomes are worse after lesser resection; the difference is slightly attenuated with increasing age. Reported short-term outcomes are quite acceptable in (selected) patients with severely limited pulmonary reserve, not clearly altered by resection extent but substantially improved by a minimally invasive approach. Quality-of-life (QOL) and impact on pulmonary function hasn\u27t been well studied, but there appears to be little difference by resection extent in older or compromised patients. Patient selection is paramount but not well defined. Ground-glass and screen-detected tumors exhibit favorable long-term outcomes regardless of resection extent; however solid tumors \u3c1 cm are not a reliably favorable group.
Conclusions: A systematic, comprehensive summary of evidence regarding resection extent in compromised patients and favorable tumors with attention to aspects of applicability, uncertainty and effect modifiers provides a foundation for a framework for individualized decision-making
Measuring and Modelling the Redshift Evolution of Clustering: the Hubble Deep Field North
(abridged) The evolution of galaxy clustering from z=0 to z=4.5 is analyzed
using the angular correlation function and the photometric redshift
distribution of galaxies brighter than I_{AB}\le 28.5 in the HDF North. The
reliability of the photometric redshift estimates is discussed on the basis of
the available spectroscopic redshifts, comparing different codes and
investigating the effects of photometric errors. The redshift bins in which the
clustering properties are measured are then optimized to take into account the
uncertainties of the photometric redshifts. The results show that the comoving
correlation length has a small decrease in the range 0<z<1 followed by an
increase at higher z. We compare these results with the theoretical predictions
of a variety of cosmological models belonging to the general class of CDM. The
comparison with the expected mass clustering evolution indicates that the
observed high-redshift galaxies are biased tracers of the dark matter with an
effective bias b strongly increasing with redshift. Assuming an Einstein-de
Sitter universe, we obtain b\simeq 2 at z=2 and b\simeq 5 at z=4. A comparison
of the clustering amplitudes that we measured at z=3 with those reported for
LBG suggests that the clustering depends on the abundance of the objects: more
abundant objects are less clustered, as expected in the paradigm of
hierarchical galaxy formation. The strong clustering and high bias measured at
z=3 are consistent with the expected density of massive haloes predicted for
the various cosmologies here considered. At z=4, the strong clustering observed
in the HDF requires a significant fraction of massive haloes to be already
formed by that epoch. This feature could be a discriminant test for the
cosmological parameters if confirmed by future observations.Comment: 23 pages, Latex using MN style, figures enclosed. Version accepted
for publication in MNRA
A guide for managing patients with stage I NSCLC: Deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 4: Systematic review of evidence involving SBRT and ablation
Background: Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options [lobectomy, segmentectomy, wedge, stereotactic body radiotherapy (SBRT), thermal ablation], weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.
Methods: A PubMed systematic review from 2000-2021 of outcomes after SBRT or thermal ablation
Results: Short-term outcomes are meaningfully better after SBRT than resection. SBRT doesn\u27t affect quality-of-life (QOL), on average pulmonary function is not altered, but a minority of patients may experience gradual late toxicity. Adjusted non-randomized comparisons demonstrate a clinically relevant detriment in long-term outcomes after SBRT
Conclusions: A systematic, comprehensive summary of evidence regarding Stereotactic Body Radiotherapy or thermal ablatio
Effects of Heat Exposure on Body Water Assessed using Single-Frequency Bioelectrical Impedance Analysis and Bioimpedance Spectroscopy
International Journal of Exercise Science 10(7): 1085-1093, 2017. The purpose of this study was to determine if heat exposure alters the measures of total body water (TBW), extracellular water (ECW), and intracellular water (ICW) in both single-frequency bioelectrical impedance analysis (BIA) and bioimpedance spectroscopy (BIS). Additionally, we sought to determine if any differences exist between the BIA and BIS techniques before and after brief exposure to heat. Body water was evaluated for twenty men (age=24±4 years) in a thermoneutral environment (22°C) before (PRE) and immediately after (POST) 15 min of passive heating (35°C) in an environmental chamber. The mean difference and 95% limits of agreement at PRE demonstrated that BIS yielded significantly higher body water values than BIA (all p0.05; 0.2±1.5kg). Additionally, the ES of the mean differences at POST were trivial to small and the r-values were high (r≥0.96). When analyzing the changes in body water before and after heat exposure, POST values for BIS were significantly higher than PRE (all
The X-ray luminous cluster underlying the z = 1.04 quasar PKS1229-021
We present a 100 ks Chandra observation studying the extended X-ray emission
around the powerful z=1.04 quasar PKS1229-021. The diffuse cluster X-ray
emission can be traced out to ~15 arcsec (~120 kpc) radius and there is a drop
in the calculated hardness ratio inside the central 5 arcsec consistent with
the presence of a cool core. Radio observations of the quasar show a strong
core and a bright, one-sided jet leading to the SW hot spot and a second hot
spot visible on the counter-jet side. Although the wings of the quasar PSF
provided a significant contribution to the total X-ray flux at all radii where
the extended cluster emission was detected, we were able to accurately subtract
off the PSF emission using ChaRT and marx simulations. The resulting steep
cluster surface brightness profile for PKS1229-021 appears similar to the
profile for the FRII radio galaxy 3C444, which has a similarly rapid surface
brightness drop caused by a powerful shock surrounding the radio lobes (Croston
et al.). Using a model surface brightness profile based on 3C444, we estimated
the total cluster luminosity for PKS1229-021 to be L_X ~ 2 x 10^{44} erg/s. We
discuss the difficulty of detecting cool core clusters, which host bright X-ray
sources, in high redshift surveys.Comment: 10 pages, 9 figures, accepted by MNRA
Barcoding Bugs: DNA-Based Identification of the True Bugs (Insecta: Hemiptera: Heteroptera)
oxidase I (COI) gene, has been shown to provide an efficient method for the identification of species in a wide range of animal taxa. In order to assess the effectiveness of barcodes in the discrimination of Heteroptera, we examined 344 species belonging to 178 genera, drawn from specimens in the Canadian National Collection of Insects.Analysis of the COI gene revealed less than 2% intra-specific divergence in 90% of the taxa examined, while minimum interspecific distances exceeded 3% in 77% of congeneric species pairs. Instances where barcodes fail to distinguish species represented clusters of morphologically similar species, except one case of barcode identity between species in different genera. Several instances of deep intraspecific divergence were detected suggesting possible cryptic species.Although this analysis encompasses 0.8% of the described global fauna, our results indicate that DNA barcodes will aid the identification of Heteroptera. This advance will be useful in pest management, regulatory and environmental applications and will also reveal species that require further taxonomic research
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