1,842 research outputs found
Understanding the decision to marry versus cohabit: the role of interpersonal dedication and constraints and the impact on life satisfaction
The current study explored men's and women's reasons for choosing to marry rather than to cohabit using a national data set (n = 786) of adults who were currently married or had been married previously. Using commitment theory participant's open-ended reasons for choosing to marry were coded into categories of either interpersonal dedication or constraint commitment. A variety of demographic, attitudinal, and relationship history variables were then used to predict commitment type. The influence of commitment type during the decision to marry on life satisfaction was also explored. Results indicate that current marital status (being married vs. being divorced or separated) and cohabiting before marriage were the strongest predictors of interpersonal dedication reasons for marriage for both men and women. Level of conventionality and parents' marital status also emerged as significant predictors of constraint commitment. Finally, marrying for reasons related to interpersonal dedication significantly predicted higher life satisfaction for men but not for women
Techniques to increase silage stability and starch availability and the effects of heat stress abatement systems on reducing heat load in dairy cattle
Doctor of PhilosophyDepartment of Animal Sciences and IndustryMicheal J. BroukFour studies were conducted that focused either on silage quality parameters or heat abatement systems to improve cow comfort. Study 1 evaluated the effects of treating whole-plant corn at harvest with a dual-purpose commercial silage inoculant containing Lactobacillus buchneri and Lactococcus lactis O224 on fermentation and aerobic stability of corn silage through 32 d of ensiling. Inoculating silage to be fed after minimal storage time (≤ 32 d post-harvest) had no effect (P > 0.05) on the chemical composition, fermentation variables, aerobic stability or rise in temperature post-harvest. Study 2 was designed to develop a berry processing score (BPS) for sorghum silage as well as evaluate the change in starch digestibility as the level of berry processing increased. A method to evaluate the level of processing in sorghum silage was successfully developed by measuring the percent of starch passing through a 1.7 mm screen. This provides the industry with a standardized method to measure the level of processing in sorghum silage. As BPS increased from 26.28 to 55.05 ± 0.04%, 7-h in situ starch digestibility increased from 50.54 to 82.07 ± 4.94% for unprocessed and heavily processed sorghum silage, respectively (R² = 0.43). By processing sorghum silage during harvest and measuring the extent of processing, sorghum silage starch digestibility can be enhanced and may serve as a viable alternative to corn silage in the diet of lactating dairy cows in areas of the country where corn silage is a high-risk forage crop due to lack of water. Study 3 evaluated the effects of 2 heat stress abatement systems on barn temperature, micro-environmental temperature, core body temperature (CBT), respiration rate, rear udder temperature, and lying time in lactating dairy cows. The systems evaluated were: direct cooling via feedline soakers and fans, or evaporative cooling via a fan and fog system. The evaporative cooling system was effective (P = 0.04) in reducing respiration rates (52.0 vs. 57.9 ± 2.2 breaths per min; P < 0.01) and rear udder
temperatures (33.2 vs. 34.5 ± 0.3ºC; P 0.05) between direct cooling and evaporative cooling were detected for micro-environmental THI. However, the evaporative cooling system reduced the consumption of water in the holding area while maintaining CBT < 39.0ºC. Future research should be conducted under greater ambient THI to determine if an evaporative cooling system is able to maintain CBT < 39.0ºC, while also comparing CBT and water usage to a soaker system in the holding area
Use of Evaporative Cooling Systems and Their Effects on Core Body Temperature and Lying Times in Lactating Dairy Cattle
A study was performed to assess the effect of an evaporative cooling system on respiration rates, rear udder temperature (Tu), core body temperature (CBT), and resting time in lactating dairy cows. Cows were divided into two treatment groups and rotated between two facilities. Cows were either housed in a bedded pack barn (PACK) equipped with an evaporative cooling system (Cyclone fans, Chippewa Falls, WI) or a tie-stall barn (TIE) equipped with cooling cells. Cows housed in PACK had two cooling treatments: FAN (Cyclone fans only, no fog); and FANFOG (Cyclone fans and fog on). Groups of cows rotated between TIE and PACK every 8 hours, and effects of housing as well as cooling treatment within PACK were analyzed. During FANFOG, PACK cows had a reduction (P \u3c 0.05) in respiration rate (breaths per minute) in comparison to TIE (69 vs 76 ± 2.4 BPM). Breaths per minute also increased significantly throughout the day for TIE but this was not the case for PACK. No differences were found in Tu between treatments. While exposed to the FANFOG environment, cows spent decreased time above 102.2°F CBT when compared to FAN. Cows housed in PACK during FAN and FANFOG also spent fewer hours/ day above 102.2°F CBT vs TIE. Cows housed in TIE showed numerically greater total daily lying times during FAN and FANFOG compared to cows housed in PACK, although these results were not significant. These results confirm that evaporative cooling systems (Cyclone fans and fog) are effective at decreasing respiration rates and CBT, while having no effect on Tu and lying times in lactating dairy cows
A Multiwavelength Classification and Study of Red Supergiant Candidates in NGC 6946
We have combined resolved stellar photometry from Hubble Space Telescope
(\emph{HST}), \emph{Spitzer}, and \emph{Gaia} to identify red supergiant (RSG)
candidates in NGC~6946, based on their colors, proper motions, visual
morphologies, and spectral energy distributions. We start with a large sample
of 17,865 RSG candidates based solely on \emph{HST} near-infrared photometry.
We then chose a small sample of 385 of these candidates with Spitzer matches
for more detailed study. Using evolutionary models and isochrones, we isolate a
space where RSGs would be found in our photometry catalogs. We then visually
inspect each candidate and compare to Gaia catalogs to identify and remove
foreground stars. As a result, we classify 95 potential RSGs, with 40 of these
being in our highest-quality sample. We fit the photometry of the populations
of stars in the regions surrounding the RSGs to infer their ages. Placing our
best candidate RSG stars into three age bins between 1 and 30 Myr, we find
27.5\% of the candidates falling between 1-10 Myr, 37.5\% between 10-20 Myr,
and 35\% 20-30 Myr. A comparison of our results to the models of massive star
evolution shows some agreement between model luminosities and the luminosities
of our candidates for each age. Three of our candidates appear significantly
more consistent with binary models than single-star evolution models.Comment: 32 pages, 18 figures, 4 table
Benefit of "Push-pull" Locomotion for Planetary Rover Mobility
As NASAs exploration missions on planetary terrains become more aggressive, a focus on alternative modes of locomotion for rovers is necessary. In addition to climbing steep slopes, the terrain in these extreme environments is often unknown and can be extremely hard to traverse, increasing the likelihood of a vehicle or robot becoming damaged or immobilized. The conventional driving mode in which all wheels are either driven or free-rolling is very efficient on flat hard ground, but does not always provide enough traction to propel the vehicle through soft or steep terrain. This paper presents an alternative mode of travel and investigates the fundamental differences between these locomotion modes. The methods of push-pull locomotion discussed can be used with articulated wheeled vehicles and are identified as walking or inchinginch-worming. In both cases, the braked non-rolling wheels provide increased thrust. An in-depth study of how soil reacts under a rolling wheel vs. a braked wheel was performed by visually observing the motion of particles beneath the surface. This novel technique consists of driving or dragging a wheel in a soil bin against a transparent wall while high resolution, high-rate photographs are taken. Optical flow software was then used to determine shearing patterns in the soil. Different failure modes were observed for the rolling and braked wheel cases. A quantitative comparison of inching vs. conventional driving was also performed on a full-scale vehicle through a series of drawbar pull tests in the Lunar terrain strength simulant, GRC-1. The effect of tire stiffness was also compared; typically compliant tires provide better traction when driving in soft soil, however its been observed that rigid wheels may provide better thrust when non-rolling. Initial tests indicate up to a possible 40 increase in pull force capability at high slip when inching vs. rolling
Factors that differentiate distressed and non-distressed marriages in army soldiers
Data from U.S. Army soldiers (N = 697) were analyzed to determine the factors that differentiate distressed from non-distressed relationships. Results show that most soldiers had relationship satisfaction scores that categorized them as non-distressed. In addition, soldiers in dual-military marriages had relationship satisfaction scores similar to those of soldiers in military-civilian marriages. Finally, several variables including rank, relocation status, relationship length, and relationship status differentiated distressed from non-distressed relationships. Implications for intervention programming and future research directions are discussed
Multi-couple group and self-directed PREP formats enhance relationship satisfaction and improve anger management skills in Air Force couples
This study examined the effectiveness of delivering the Prevention and Relationship Enhancement Program (PREP) to volunteer couples in the U.S. Air Force in either a six-week instructional multi-couple group condition or a self-directed book condition. A standardized pre/post protocol was employed and outcomes included relationship satisfaction and anger management skills, two known risk factors for partner maltreatment. Significant improvement was found for the group condition in both relationship satisfaction and anger management skills, but only for anger management skills in the self-directed book condition. Finally, the group condition reported greater program satisfaction. Implications are discussed
Comparative outcomes between COVID-19 and influenza patients placed on veno-venous extracorporeal membrane oxygenation for severe ARDS
Background ECMO is an established supportive adjunct for patients with severe, refractory ARDS from viral pneumonia. However, the exact role and timing of ECMO for COVID-19 patients remains unclear. Methods We conducted a retrospective comparison of the first 32 patients with COVID-19-associated ARDS to the last 28 patients with influenza-associated ARDS placed on V-V ECMO. We compared patient factors between the two cohorts and used survival analysis to compare the hazard of mortality over sixty days post-cannulation.Results COVID-19 patients were older (mean 47.8 vs. 41.2 years, p = 0.033), had more ventilator days before cannulation (mean 4.5 vs. 1.5 days, p < 0.001). Crude in-hospital mortality was significantly higher in the COVID-19 cohort at 65.6% (n = 21/32) versus 36.3% (n = 11/28, p = 0.041). The adjusted hazard ratio over sixty days for COVID-19 patients was 2.81 (95% CI 1.07, 7.35) after adjusting for age, race, ECMO-associated organ failure, and Charlson Comorbidity Index. Conclusion ECMO has a role in severe ARDS associated with COVID-19 but providers should carefully weigh patient factors when utilizing this scarce resource in favor of influenza pneumonia
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