379 research outputs found
Weak Interactions in Atoms and Nuclei: The Standard Model and Beyond
Studies in nuclear and atomic physics have played an important role in
developing our understanding of the Standard Model of electroweak interactions.
We review the basic ingredients of the Standard Model, and discuss some key
nuclear and atomic physics experiments used in testing these ideas. We also
summarize the conceptual issues of the Standard Model that motivate the search
for new physics.Comment: 51 pages, 25 figure
Was 49b: An Overmassive AGN in a Merging Dwarf Galaxy?
We present a combined morphological and X-ray analysis of Was 49, an
isolated, dual AGN system notable for the presence of a dominant AGN Was 49b in
the disk of the primary galaxy Was 49a, at a projected radial distance of 8 kpc
from the nucleus. Using X-ray data from Chandra, NuSTAR, and Swift, we find
that this AGN has a bolometric luminosity of L_bol ~ 2 x 10^45 erg/s, with a
black hole mass of M_BH=1.3^{+2.9}_{-0.9} x 10^8 M_Sol. Despite its large mass,
our analysis of optical data from the Discovery Channel Telescope shows that
the supermassive black hole is hosted by a stellar counterpart with a mass of
only 5.6^{+4.9}_{-2.6} x 10^9 M_Sol, making the SMBH potentially larger than
expected from SMBH-galaxy scaling relations, and the stellar counterpart
exhibits a morphology that is consistent with dwarf elliptical galaxies. Our
analysis of the system in the r and K bands indicates that Was 49 is a minor
merger, with a mass ratio of Was 49a to Was 49b between 1:7 and 1:15. This is
in contrast with findings that the most luminous merger-triggered AGNs are
found in major mergers, and that minor mergers predominantly enhance AGN
activity in the primary galaxy.Comment: 11 pages, 6 figures, accepted for publication in Ap
Radio-Optical Reference Catalog, version 1
The fundamental celestial reference frame (CRF) is based on two catalogs of
astrometric positions, the third realization of the International Celestial
Reference Frame (ICRF3), and the much larger Gaia~CRF, built from the third
data release (DR3). The objects in common between these two catalogs are mostly
distant AGNs and quasars that are both sufficiently optically bright for Gaia
and radio-loud for the VLBI. This limited collection of reference objects is
crucially important for the mutual alignment of the two CRFs and maintenance of
all the other frames and coordinate systems branching from the ICRF. In this
paper, we show that the three components of ICRF3 (S/X, K, and X/Ka band
catalogs) have significantly different sky-correlated vector fields of position
offsets with respect to Gaia~DR3. When iteratively expanded in the vector
spherical harmonics up to degree 4 on a carefully vetted set of common sources,
each of these components includes several statistically significant terms. The
median sky-correlated offsets from the Gaia positions are found to be 56
as for the S/X, 100 as for the K, and 324 as for the Ka
catalogs. The weighted mean vector field is subtracted from the Gaia reference
positions, while the deviations from that field are added to each of the ICRF3
components. The corrected positions from each of the four input catalogs are
combined into a single weighted mean catalog, which we propose to be the
current most accurate realization of an inertial radio-optical CRF.Comment: To be published in A
A water-vapor electrolysis cell with phosphoric acid electrolyte
Feasibility of phosphoric acid water vapor electrolysis cell for spacecraft cabin air conditioning syste
Buried AGNs in Advanced Mergers:Mid-infrared color selection as a dual AGN finder
A direct consequence of hierarchical galaxy formation is the existence of
dual supermassive black holes (SMBHs), which may be preferentially triggered as
active galactic nuclei (AGN) during galaxy mergers. Despite decades of
searching, however, dual AGNs are extremely rare, and most have been discovered
serendipitously. Using the all-sky WISE survey, we identified a population of
over 100 morphologically identified interacting galaxies or mergers that
display red mid-infrared colors often associated in extragalactic sources with
powerful AGNs. The vast majority of these advanced mergers are optically
classified as star-forming galaxies suggesting that they may represent an
obscured population of AGNs that cannot be found through optical studies. In
this work, we present Chandra/ACIS observations and near-infrared spectra with
the Large Binocular Telescope of six advanced mergers with projected pair
separations less than ~ 10 kpc. The combined X-ray, near-infrared, and
mid-infrared properties of these mergers provide confirmation that four out of
the six mergers host at least one AGN, with four of the mergers possibly
hosting dual AGNs with projected separations less than ~10 kpc, despite showing
no firm evidence for AGNs based on optical spectroscopic studies. Our results
demonstrate that 1) optical studies miss a significant fraction of single and
dual AGNs in advanced mergers, and 2) mid-infrared pre-selection is extremely
effective in identifying dual AGN candidates in late-stage mergers. Our
multi-wavelength observations suggest that the buried AGNs in these mergers are
highly absorbed, with intrinsic column densities in excess of N_H >10^24cm^-2,
consistent with hydrodynamic simulations.Comment: 23 pages, 11 figures, accepted for publication to Ap
The Effects of Ammonia Inhalants on Anaerobic Performance Following a Simulated American Football Game
Ammonia inhalants (AI) are anecdotally referred to as ergogenic aids in the realm of aggressive team/lifting sports. However, the efficacy of AI usage has yet to be established or reported to our knowledge. Therefore, the purpose of this study was to establish the effects of AI’s on anaerobic performance following a simulated American football game (SAFG) in a climate controlled setting (35.8 °C, 27.5% RH). METHODS: Ten apparently healthy anaerobically trained college-aged males participated dressed in American football apparel, excluding the helmet. Each subject participated in two trials, 136 minutes each, separated by a minimum of 48 hours (AI or control). Each SAFG consisted of a randomized counter-balanced series of sprints. The sprint protocol was made up of a total 12, 9, or 6 sprints, which were experienced each half of the SAFG in a randomized order. The individual sprints consisted of 5 second maximal effort sprints which were followed by 40 seconds of rest, simulating what one would expect in an American football game. The Wingate anaerobic test (WAnT) was performed before and after each SAFG in a neutral temperature (21.3°C, 30.8% RH). Resistance for the 30-second WAnT was calculated at 10% of each respective subject’s weight in kilograms (kg). The AI condition was administered by capsule immediately before the final WAnT. Paired t-tests were used to examine differences in peak power change (ΔPP) and mean power change (ΔMP) from WAnTs performed pre-post-SAFG. α=0.05. RESULTS: The majority of our subjects elicited an increase in PP (9/10 subjects) and MP (8/10 subjects) during the AI condition. The ΔPP in the AI (134±85 W) trial was significantly greater that the control trial (59±108 W) (p≤.05). Likewise, ΔMP in the AI (35±53 W) was significantly greater than the control (-21±65 W) trial (p≤.01). CONCLUSION: These results suggest that the intervention of AI following a bout of fatiguing work is successful in the in the generation of maximal power outputs as well as attenuating fatigue within the WAnT. Thereby, suggesting that when performing a WAnT, utilizing AI as an intervention can increase power output. Further research should be conducted in order to support the findings from the present investigation and possible applications
Establishing the Learned Effect of Repeated Wingate Anaerobic Tests
The Wingate anaerobic test (WAnT) is a recognized and well-established measure of power output, muscular endurance, and fatigue. However, a learning effect could reduce the reliability of these measures. PURPOSE: To establish the number of WAnT trials needed to produce a learned effect. METHODS: Thirty-six apparently healthy college-aged men (n=20) and women (n=16) who had not previously performed a WAnT participated in five WAnT trials separated by a minimum of 72 hours. Peak Power (PP) and Mean Power (MP) were recorded for each trial. Resistance for trials was calculated at 7.5% of each respective participant’s weight. RESULTS: In men, paired samples t-test revealed PP increased on all trials (2-5) when compared to trial 1 (+44.66W, +49.19W, +55.80W, +63.95W; p=0.02, p=0.01, p=0.01, p=0.00, respectively). PP significantly increased from trial 1 to trial 2 (849.21±127.41 watts to 893.87±143.92 watts, p\u3c.05), but leveled thereafter with no significant differences between trials 2-5 (p\u3e.05). The same results were found for MP, with a significant increase from trial 1 to 2 (627.90±79.01 watts to 660.04±79.66 watts, p\u3c.01), but no differences found between trials 2-5 (p\u3e.05). There was a trend toward an elicited peak MP at trial 3 (p=.09, Cohen’s d= -.83). In women, the average PP and MP for trial 1 was 547.74±94.56 watts and 415.91±68.21 watts, respectively, with no significant differences found between trials (p\u3e.05). These results suggest that a learned effect is present within PP and MP until trial 2 of the WAnT, with a trend toward peak MP at trial 3 for male participants. CONCLUSION: Thereby, suggesting that when performing WAnT, utilizing less than 3 practice trials might elicit significant power increase in male participants due to this learned effect. Current data suggests that female participants elicit peak power at trial 1 of the WAnT, with no significant increase in subsequent trials. Additional research should be conducted in order to further investigate the non-significant trend of increasing power output across WAnT trials in male participants as well the lack of female learned response
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