1,534 research outputs found
What is on Tap? The Role of Spin in Compact Objects and Relativistic Jets
We examine the role of spin in launching jets from compact objects across the
mass scale. Our work includes a total of 37 Seyferts, 11 stellar-mass black
holes, and 13 neutron stars. We find that when the Seyfert reflection lines are
modeled with Gaussian line features (a crude proxy for inner disk radius and
therefore spin), only a slight inverse correlation is found between the
Doppler-corrected radio luminosity at 5 GHz (a proxy for jet power) and line
width. When the Seyfert reflection features are fit with
relativistically-blurred disk reflection models that measure spin, there is a
tentative positive correlation between the Doppler-corrected radio luminosity
and the spin measurement. Further, when we include stellar-mass black holes in
the sample, to examine the effects across the mass scale, we find a slightly
stronger correlation with radio luminosity per unit mass and spin, at a
marginal significance (2.3 sigma confidence level). Finally, when we include
neutron stars, in order to probe lower spin values, we find a positive
correlation (3.3 sigma confidence level) between radio luminosity per unit mass
and spin. Although tentative, these results suggest that spin may have a role
in determining the jet luminosity. In addition, we find a slightly more
significant correlation (4.4 sigma confidence level) between radio luminosity
per Bolometric luminosity and spin, using our entire sample of black holes and
neutrons stars. Again, although tentative, these relations point to the
possibility that the mass accretion rate, i.e. Bolometric luminosity, is also
important in determining the jet luminosity, in addition to spin. Our analysis
suggests that mass accretion rate and disk or coronal magnetic field strength
may be the "throttle" in these compact systems, to which the Eddington limit
and spin may set the maximum jet luminosity that can be achieved.Comment: 14 pages, 13 Figures, ApJ Accepte
Adverse Childhood Experiences and Current Cannabis Use among U.S. Young Adults
Cannabis use is a significant public health issue among U.S. young adults. The objective of this study was to assess the associations between adverse childhood experiences (ACEs) and current cannabis use among U.S. young adults. We conducted a secondary analysis of the 2021 Behavioral Risk Factor Surveillance System (BRFSS) data, which involved 498 U.S. young adults 18-24 years old who had data available for analysis on ACEs and current cannabis use. Unadjusted and adjusted logistic regression models were fitted to examine the associations between ACEs and current cannabis use. Adjusted models included participants’ sex, race/ethnicity, education level, and household income level. One-fourth (25.5%) of participants reported current cannabis use, and 21.3% reported one ACE, 25.2% reported 2-3 ACEs, and 38.4% reported ≥4 ACEs. Unadjusted (odds ratio [OR]=4.22, 95% confidence interval [CI]=1.91-9.33) and adjusted (adjusted OR=4.23, 95%CI=1.57-11.38) model results indicated that participants who experienced ≥1 ACE were at increased odds of reporting current cannabis use than participants with no ACEs. Unadjusted (OR=5.79, 95%CI=2.40-14.00) and adjusted (AOR=6.48, 95%CI=2.15-19.55) model results indicated that participants who experienced ≥4 ACEs were at increased odds of reporting current cannabis use than participants with no ACEs. Adjusted model results revealed that experiencing living with a household member who had a mental illness or sexual abuse increased the odds of reporting current cannabis use. Results demonstrated relations among ACEs and current cannabis use in young adulthood, especially among those who experienced ≥4 ACEs and experienced living with a household member who had a mental illness or sexual abuse
The diversity of CM carbonaceous chondrite parent bodies explored using Lewis Cliff 85311
Lewis Cliff (LEW) 85311 is classified as a Mighei-like (CM) carbonaceous chondrite, yet it has some unusual properties that highlight an unrealised diversity within the CMs, and also questions how many parent bodies are sampled by the group. This meteorite is composed of rimmed chondrules, chondrule fragments and refractory inclusions that are set in a fine-grained phyllosilicate-rich matrix. The chondrules are of a similar size to those in the CMs, and have narrow fine-grained rims. LEW 85311 has been mildly aqueously altered, as evidenced by the preservation of melilite and kamacite, and X-ray diffraction results showing a low phyllosilicate fraction and a high ratio of cronstedtite to Fe,Mg serpentine. The chemical composition of LEW 85311 matrix, fine-grained rims, tochilinite and P-rich sulphides is similar to mildly aqueously altered CMs. LEW 85311 is enriched in refractory elements and REEs such that its CI-normalised profile falls between the CMs and CVs, and its oxygen isotopic composition plots in the CV-CK-CO field. Other distinctive properties of this meteorite include the presence of abundant refractory inclusions, and hundreds of micrometer size objects composed of needle-fibre calcite. LEW 85311 could come from part of a single CM parent body that was unusually rich in refractory inclusions, but more likely samples a different parent body to most other members of the group that accreted a subtly different mixture of materials. The mineralogical and geochemical evolution of LEW 85311 during subsequent aqueous alteration was similar to other CMs and was arrested at an early stage, corresponding to a petrologic subtype of CM2.7, probably due to an unusually low proportion of accreted ice. The CM carbonaceous chondrites sample multiple parent bodies whose similar size and inventory of accreted materials, including radiogenic isotopes, led to a comparable post-accretionary evolution
Effect of harvest method and ammoniation of baled corn residue on intake and digestibility in lambs
To determine the effect of harvest method and ammoniation on both in vivo and in vitro digestibility of corn residue, six corn residue treatments consisting of three different harvest methods either with or without anhydrous ammonia chemical treatment (5.5% of dry matter [DM]) were evaluated. The harvest methods included conventional rake-and-bale (CONV) and New Holland Cornrower with eight rows (8ROW) or two rows (2ROW) of corn stalks chopped into the windrow containing the tailings (leaf, husk, and upper stem) from eight rows of harvested corn (ammoniated bales of each harvest method resulted in treatments COVAM, 8RAM, and 2RAM). Nine crossbred wether lambs (49.2 ± 0.5 kg BW) were fed 64.2% corn residue, 29.8% wet corn gluten feed, 3.3% smooth-bromegrass hay, and 2.8% mineral mix (DM basis) in a 9 × 6 Latin rectangle metabolism study with a 3 × 2 factorial treatment to measure total tract disappearance. Six 21-d periods consisted of 14-d adaptation and 7-d total fecal collection, and lambs were fed ad libitum (110% of the previous day’s DM intake [DMI]) during days 1 to 12 and reduced to 95% of ad libitum intake for days 13 to 21. There was a harvest method by ammoniation interaction (P \u3c 0.01) for ad libitum DMI (days 7 to 11). Ammoniation increased (P \u3c 0.01) intake across all harvest methods, where 2RAM DMI was 4.1%, COVAM was 3.6%, and 8RAM was 3.1%, which were all different (P \u3c 0.01) from each other, but all untreated residues were consumed at 2.6% of BW (P ≥ 0.92) regardless of harvest method. There were no interactions (P \u3e 0.34) between harvest method and ammoniation for any total tract or in vitro digestibility estimate. Harvest method affected (P \u3c 0.04) DM, neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibility, where 2ROW was greater than both CONV and 8ROW, which did not differ. The organic matter (OM) digestibility (P = 0.12) and digestible energy (DE; P = 0.30) followed the same numerical trend. Both in vitro DM digestibility (IVDMD) and in vitro OM digestibility (IVOMD) of the residue were affected (P \u3c 0.01) by harvest method, with 2ROW being greater (P \u3c 0.01) than both CONV and 8ROW. For IVDMD, 8ROW was not (P = 0.77) different from CONV, but 8ROW IVOMD was lower (P = 0.03) than CONV. Ammoniation improved (P \u3c 0.01) DM, OM, NDF, and ADF digestibility of all harvest methods, resulting in a 26% increase (P \u3c 0.01) in DE due to ammoniation. Similar digestibility improvements were observed in vitro with ammoniation improving IVDMD and IVOMD by 23% and 20%, respectively. Both selective harvest methods and ammoniation can improve the feeding value of baled corn residue
Effect of Harvest Method and Ammoniation on Digestibility and Intake of Corn Residue
The effects of three harvest methods, both with and without ammonia treatment, on the in vivo digestibility and intake of baled corn residue were assessed in a digestion trial with lambs. Treatments included three corn residue harvest methods (conventional rake and bale, New Holland Cornrower™ with eight rows or with two rows of corn stalks chopped into the windrow containing the tailings [leaf, husk and upper stalk] from eight harvested rows) and the effects of ammoniation at 5.5% of DM compared to no ammoniation of the residue. Th e 2- Row baled residue (51.7%) had greater dry matter digestibility than both 8- Row (47.3%) and CONV (44.7%). Ammoniation increased dry matter digestibility by 24% (10 percentage units) across all residue types. Additionally, ammoniation increased intake. Utilizing alternative harvesting technologies and ammoniation can improve the digestibility of baled residue. These effects are additive and combining the two technologies resulted in the greatest improvement in digestibility
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Fortification and health: challenges and opportunities.
Fortification is the process of adding nutrients or non-nutrient bioactive components to edible products (e.g., food, food constituents, or supplements). Fortification can be used to correct or prevent widespread nutrient intake shortfalls and associated deficiencies, to balance the total nutrient profile of a diet, to restore nutrients lost in processing, or to appeal to consumers looking to supplement their diet. Food fortification could be considered as a public health strategy to enhance nutrient intakes of a population. Over the past century, fortification has been effective at reducing the risk of nutrient deficiency diseases such as beriberi, goiter, pellagra, and rickets. However, the world today is very different from when fortification emerged in the 1920s. Although early fortification programs were designed to eliminate deficiency diseases, current fortification programs are based on low dietary intakes rather than a diagnosable condition. Moving forward, we must be diligent in our approach to achieving effective and responsible fortification practices and policies, including responsible marketing of fortified products. Fortification must be applied prudently, its effects monitored diligently, and the public informed effectively about its benefits through consumer education efforts. Clear lines of authority for establishing fortification guidelines should be developed and should take into account changing population demographics, changes in the food supply, and advances in technology. This article is a summary of a symposium presented at the ASN Scientific Sessions and Annual Meeting at Experimental Biology 2014 on current issues involving fortification focusing primarily on the United States and Canada and recommendations for the development of responsible fortification practices to ensure their safety and effectiveness
Counterexamples to additivity of minimum output p-Renyi entropy for p close to 0
Complementing recent progress on the additivity conjecture of quantum
information theory, showing that the minimum output p-Renyi entropies of
channels are not generally additive for p>1, we demonstrate here by a careful
random selection argument that also at p=0, and consequently for sufficiently
small p, there exist counterexamples.
An explicit construction of two channels from 4 to 3 dimensions is given,
which have non-multiplicative minimum output rank; for this pair of channels,
numerics strongly suggest that the p-Renyi entropy is non-additive for all p <
0.11. We conjecture however that violations of additivity exist for all p<1.Comment: 7 pages, revtex4; v2 added correct ref. [15]; v3 has more information
on the numerical violation as well as 1 figure (2 graphs) - note that the
explicit example was changed and the more conservative estimate of the bound
up to which violations occur, additionally some other small issues are
straightened ou
Disseminated Effects in Agent Based Models: A Potential Outcomes Framework and Application to Inform Pre-Exposure Prophylaxis Coverage Levels for HIV Prevention
Pre-exposure prophylaxis (PrEP) for HIV prevention may not only benefit the individual who uses it, but also their uninfected sexual risk contacts. We developed an agent-based model using a novel trial emulation approach to quantify disseminated effects of PrEP use among men who have sex with men in Atlanta, USA from 2015 to 2017. Components (subsets of agents connected through partnerships in a sexual network, but not sharing partnerships with any other agents) were first randomized to an intervention coverage level or control, then within intervention components, eligible agents were randomized to PrEP. We estimated direct and disseminated (indirect) effects using randomization-based estimators and reported corresponding 95% simulation intervals across scenarios ranging from 10% to 90% coverage in the intervention components. A population of 11,245 agents was simulated with an average of 1,551 components identified. Comparing agents randomized to PrEP in 70% coverage components to control agents, there was a 15% disseminated risk reduction in HIV incidence (95% simulation intervals = 0.65, 1.05). Individuals not on PrEP may receive a protective benefit by being in a sexual network with higher PrEP coverage. Agent-based models are useful to evaluate possible direct and disseminated effects of HIV prevention modalities in sexual networks
A NuSTAR observation of the reflection spectrum of the low mass X-ray binary 4U 1728-34
We report on a simultaneous NuSTAR and Swift observation of the neutron star
low-mass X-ray binary 4U 1728-34. We identified and removed four Type I X-ray
bursts during the observation in order to study the persistent emission. The
continuum spectrum is hard and well described by a black body with 1.5
keV and a cutoff power law with 1.5 and a cutoff temperature of 25
keV. Residuals between 6 and 8 keV provide strong evidence of a broad Fe
K line. By modeling the spectrum with a relativistically blurred
reflection model, we find an upper limit for the inner disk radius of . Consequently we find that km,
assuming M=1.4{\mbox{\rm\,M_{\mathord\odot}}} and . We also find an
upper limit on the magnetic field of G.Comment: 9 pages, 8 figure
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