2,553 research outputs found
Emission Line Galaxies in the STIS Parallel Survey II: Star Formation Density
We present the luminosity function of [OII]-emitting galaxies at a median
redshift of z=0.9, as measured in the deep spectroscopic data in the STIS
Parallel Survey (SPS). The luminosity function shows strong evolution from the
local value, as expected. By using random lines of sight, the SPS measurement
complements previous deep single field studies. We calculate the density of
inferred star formation at this redshift by converting from [OII] to H-alpha
line flux as a function of absolute magnitude and find rho_dot=0.043 +/- 0.014
Msun/yr/Mpc^3 at a median redshift z~0.9 within the range 0.46<z<1.415 (H_0 =
70 km/s/Mpc, Omega_M=0.3, Omega_Lambda=0.7. This density is consistent with a
(1+z)^4 evolution in global star formation since z~1. To reconcile the density
with similar measurements made by surveys targeting H-alpha may require
substantial extinction correction.Comment: 16 preprint pages including 5 figures; accepted for publication in
Ap
M–M Bond-Stretching Energy Landscapes for M_2(dimen)_(4)^(2+) (M = Rh, Ir; dimen = 1,8-Diisocyanomenthane) Complexes
Isomers of Ir_2(dimen)_(4)^(2+) (dimen = 1,8-diisocyanomenthane) exhibit different Ir–Ir bond distances in a 2:1 MTHF/EtCN solution (MTHF = 2-methyltetrahydrofuran). Variable-temperature absorption data suggest that the isomer with the shorter Ir–Ir distance is favored at room temperature [K = ~8; ΔH° = −0.8 kcal/mol; ΔS° = 1.44 cal mol^(–1) K^(–1)]. We report calculations that shed light on M_2(dimen)_(4)^(2+) (M = Rh, Ir) structural differences: (1) metal–metal interaction favors short distances; (2) ligand deformational-strain energy favors long distances; (3) out-of-plane (A_(2u)) distortion promotes twisting of the ligand backbone at short metal–metal separations. Calculated potential-energy surfaces reveal a double minimum for Ir_2(dimen)_(4)^(2+) (4.1 Å Ir–Ir with 0° twist angle and ~3.6 Å Ir–Ir with ±12° twist angle) but not for the rhodium analogue (4.5 Å Rh–Rh with no twisting). Because both the ligand strain and A_(2u) distortional energy are virtually identical for the two complexes, the strength of the metal–metal interaction is the determining factor. On the basis of the magnitude of this interaction, we obtain the following results: (1) a single-minimum (along the Ir–Ir coordinate), harmonic potential-energy surface for the triplet electronic excited state of Ir_2(dimen)_(4)^(2+) (R_(e,Ir–Ir) = 2.87 Å; F_(Ir–Ir) = 0.99 mdyn Å^(–1)); (2) a single-minimum, anharmonic surface for the ground state of Rh_2(dimen)_(4)^(2+) (R_(e,Rh–Rh) = 3.23 Å; F_(Rh–Rh) = 0.09 mdyn Å^(–1)); (3) a double-minimum (along the Ir–Ir coordinate) surface for the ground state of Ir_2(dimen)_(4)^(2+) (R_(e,Ir–Ir) = 3.23 Å; F_(Ir–Ir) = 0.16 mdyn Å^(–1))
Phase transition in a static granular system
We find that a column of glass beads exhibits a well-defined transition
between two phases that differ in their resistance to shear. Pulses of
fluidization are used to prepare static states with well-defined particle
volume fractions in the range 0.57-0.63. The resistance to shear is
determined by slowly inserting a rod into the column of beads. The transition
occurs at for a range of speeds of the rod.Comment: 4 pages, 4 figures. The paper is significantly extended, including
new dat
Emission Line Galaxies in the STIS Parallel Survey I: Observations and Data Analysis
In the first three years of operation STIS obtained slitless spectra of
approximately 2500 fields in parallel to prime HST observations as part of the
STIS Parallel Survey (SPS). The archive contains almost 300 fields at high
galactic latitude (|b|>30) with spectroscopic exposure times greater than 3000
seconds. This sample contains 220 fields (excluding special regions and
requiring a consistent grating angle) observed between 6 June 1997 and 21
September 2000, with a total survey area of about 160 square arcminutes. At
this depth, the SPS detects an average of one emission line galaxy per three
fields. We present the analysis of these data, and the identification of 131
low to intermediate redshift galaxies detected by optical emission lines. The
sample contains 78 objects with emission lines that we infer to be redshifted
[OII]3727 emission at 0.43<z<1.7. The comoving number density of these objects
is comparable to that of H-alpha emitting galaxies in the NICMOS parallel
observations. One quasar and three probable Seyfert galaxies are detected. Many
of the emission-line objects show morphologies suggestive of mergers or
interactions. The reduced data are available upon request from the authors.Comment: 58 preprint pages, including 26 figures; accepted for publication in
ApJ
Spinal fluid IgG antibodies from patients with demyelinating diseases bind multiple sclerosis-associated bacteria
ABSTRACT: A panel of 10 IgG enzyme-linked immunosorbent assays (ELISAs) were developed for the detection of anti-microbial immune responses in the cerebrospinal fluid (CSF) of patients with demyelinating diseases (DD). The anti-microbial ELISA assays follow on prior human brain tissue RNA sequencing studies that established multiple sclerosis (MS) microbial candidates. Lysates included in the ELISA panel were derived from Akkermansia muciniphila, Atopobium vaginae, Bacteroides fragilis, Lactobacillus paracasei, Odoribacter splanchnicus, Pseudomonas aeruginosa, Cutibacterium (Propionibacterium) acnes, Fusobacterium necrophorum, Porphyromonas gingivalis, and Streptococcus mutans. CSF responses from patients with demyelinating diseases (DD, N = 14) were compared to those with other neurological diseases (OND, N = 8) and controls (N = 13). Commercial positive and negative control CSF specimens were run with each assay. ELISA index values were derived for each specimen against each of the 10 bacterial lysates. CSF reactivity was significantly higher in the DD group compared to the controls against Akkermansia, Atopobium, Bacteroides, Lactobacillus, Odoribacter, and Fusobacterium. Four of the 11 tested DD group subjects had elevated antibody indexes against at least one of the 10 bacterial species, suggesting intrathecal antibody production. This CSF serological study supports the hypothesis that several of the previously identified MS candidate microbes contribute to demyelination in some patients. KEY MESSAGES: A panel of 10 IgG enzyme-linked immunosorbent assays (ELISAs) were developed for the detection of anti-microbial immune responses in the cerebrospinal fluid (CSF) of patients with demyelinating diseases, including multiple sclerosis and acute disseminated encephalomyelitis. CSF reactivity was significantly higher in the demyelination group compared to the controls against the bacteria Akkermansia, Atopobium, Bacteroides, Lactobacillus, Odoribacter, and Fusobacterium. Several of the demyelination subjects had elevated antibody indexes against at least one of the 10 antigens, suggesting at least limited intrathecal production of anti-bacterial antibodies. This CSF serological study supports the hypothesis that several of the previously identified MS candidate microbes contribute to demyelination in some patients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00109-021-02085-z
IgA Anti-Epidermal Transglutaminase Antibodies in Dermatitis Herpetiformis and Pediatric Celiac Disease
Different doses of supplemental vitamin D maintain interleukin-5 without altering skeletal muscle strength: a randomized, double-blind, placebo-controlled study in vitamin D sufficient adults
<p>Abstract</p> <p>Background</p> <p>Supplemental vitamin D modulates inflammatory cytokines and skeletal muscle function, but results are inconsistent. It is unknown if these inconsistencies are dependent on the supplemental dose of vitamin D. Therefore, the purpose of this study was to identify the influence of different doses of supplemental vitamin D on inflammatory cytokines and muscular strength in young adults.</p> <p>Methods</p> <p>Men (<it>n </it>= 15) and women (<it>n </it>= 15) received a daily placebo or vitamin D supplement (200 or 4000 IU) for 28-d during the winter. Serum 25-hydroxyvitamin D (25(OH)D), cytokine concentrations and muscular (leg) strength measurements were performed prior to and during supplementation. Statistical significance of data were assessed with a two-way (time, treatment) analysis of variance (ANOVA) with repeated measures, followed by a Tukey's Honestly Significant Difference to test multiple pairwise comparisons.</p> <p>Results</p> <p>Upon enrollment, 63% of the subjects were vitamin D sufficient (serum 25(OH)D ≥ 30 ng/ml). Serum 25(OH)D and interleukin (IL)-5 decreased (<it>P </it>< 0.05) across time in the placebo group. Supplemental vitamin D at 200 IU maintained serum 25(OH)D concentrations and increased IL-5 (<it>P </it>< 0.05). Supplemental vitamin D at 4000 IU increased (<it>P </it>< 0.05) serum 25(OH)D without altering IL-5 concentrations. Although serum 25(OH)D concentrations correlated (<it>P </it>< 0.05) with muscle strength, muscle strength was not changed by supplemental vitamin D.</p> <p>Conclusion</p> <p>In young adults who were vitamin D sufficient prior to supplementation, we conclude that a low-daily dose of supplemental vitamin D prevents serum 25(OH)D and IL-5 concentration decreases, and that muscular strength does not parallel the 25(OH)D increase induced by a high-daily dose of supplemental vitamin D. Considering that IL-5 protects against viruses and bacterial infections, these findings could have a broad physiological importance regarding the ability of vitamin D sufficiency to mediate the immune systems protection against infection.</p
Cost-Effectiveness of Robot-Assisted Radical Cystectomy vs Open Radical Cystectomy for Patients With Bladder Cancer
IMPORTANCE: The value to payers of robot-assisted radical cystectomy with intracorporeal urinary diversion (iRARC) when compared with open radical cystectomy (ORC) for patients with bladder cancer is unclear. OBJECTIVES: To compare the cost-effectiveness of iRARC with that of ORC. DESIGN, SETTING, AND PARTICIPANTS: This economic evaluation used individual patient data from a randomized clinical trial at 9 surgical centers in the United Kingdom. Patients with nonmetastatic bladder cancer were recruited from March 20, 2017, to January 29, 2020. The analysis used a health service perspective and a 90-day time horizon, with supplementary analyses exploring patient benefits up to 1 year. Deterministic and probabilistic sensitivity analyses were undertaken. Data were analyzed from January 13, 2022, to March 10, 2023. INTERVENTIONS: Patients were randomized to receive either iRARC (n = 169) or ORC (n = 169). MAIN OUTCOMES AND MEASURES: Costs of surgery were calculated using surgery timings and equipment costs, with other hospital data based on counts of activity. Quality-adjusted life-years were calculated from European Quality of Life 5-Dimension 5-Level instrument responses. Prespecified subgroup analyses were undertaken based on patient characteristics and type of diversion. RESULTS: A total of 305 patients with available outcome data were included in the analysis, with a mean (SD) age of 68.3 (8.1) years, and of whom 241 (79.0%) were men. Robot-assisted radical cystectomy was associated with statistically significant reductions in admissions to intensive therapy (6.35% [95% CI, 0.42%-12.28%]), and readmissions to hospital (14.56% [95% CI, 5.00%-24.11%]), but increases in theater time (31.35 [95% CI, 13.67-49.02] minutes). The additional cost of iRARC per patient was £1124 (95% CI, -£576 to £2824 [US 831 to 144 312) per quality-adjusted life-year gained. Robot-assisted radical cystectomy had a much higher probability of being cost-effective for subgroups defined by age, tumor stage, and performance status. CONCLUSIONS AND RELEVANCE: In this economic evaluation of surgery for patients with bladder cancer, iRARC reduced short-term morbidity and some associated costs. While the resulting cost-effectiveness ratio was in excess of thresholds used by many publicly funded health systems, patient subgroups were identified for which iRARC had a high probability of being cost-effective. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03049410
A Pair of Compact Red Galaxies at Redshift 2.38, Immersed in a 100 kpc Scale Ly-alpha Nebula
We present Hubble Space Telescope (HST) and ground-based observations of a
pair of galaxies at redshift 2.38, which are collectively known as 2142-4420 B1
(Francis et al. 1996). The two galaxies are both luminous extremely red objects
(EROs), separated by 0.8 arcsec. They are embedded within a 100 kpc scale
diffuse Ly-alpha nebula (or blob) of luminosity ~10^44 erg/s.
The radial profiles and colors of both red objects are most naturally
explained if they are young elliptical galaxies: the most distant yet found. It
is not, however, possible to rule out a model in which they are abnormally
compact, extremely dusty starbursting disk galaxies. If they are elliptical
galaxies, their stellar populations have inferred masses of ~10^11 solar masses
and ages of ~7x10^8 years. Both galaxies have color gradients: their centers
are significantly bluer than their outer regions. The surface brightness of
both galaxies is roughly an order of magnitude greater than would be predicted
by the Kormendy relation. A chain of diffuse star formation extending 1 arcsec
from the galaxies may be evidence that they are interacting or merging.
The Ly-alpha nebula surrounding the galaxies shows apparent velocity
substructure of amplitude ~ 700 km/s. We propose that the Ly-alpha emission
from this nebula may be produced by fast shocks, powered either by a galactic
superwind or by the release of gravitational potential energy.Comment: 33 pages, 9 figures, ApJ in press (to appear in Jun 10 issue
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