1,391 research outputs found

    Factors Affecting Timing and Intensity of Calving Season of Beef Cow-Calf Producers in the Midwest

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    Despite demonstrated market incentives to adopt controlled calving seasons, many producers still have herds that calve somewhat broadly throughout the year. Primarydata, collected through a coordinated survey effort withUSDA’s National Agricultural Statistics Service, were usedto quantify factors that affect producers’ decisions regardingtiming and intensity of calving season. Ninety-seven, 50, 33,and 26% of farms calve in the spring (Mar, Apr, May),summer (Jun, Jul, Aug), fall (Sep, Oct, Nov), and winter(Dec, Jan, Feb), respectively. Twenty-two percent observeda calving season exclusively in the spring. Sixty-six percentof respondents indicated calving season was dictated byweather, 34% because of labor availability, and 31%because of tradition. Least often reasons for calving seasonwere market timing (16%), feed availability (8%), and other(4%). Producer stated reasons for calving season explained62% of the variation in timing and intensity of calving on anoperation, whereas a model of producer demographic andoperation characteristics explained 83% of the variation.These results highlight the importance of evaluatingproducer and operation characteristics in addition toproducer input when making recommendations to enhanceproduction efficiency and profitability. Furthermore,understanding the factors which impact calving seasonprovides opportunities for improved extension and research programming

    Differential Uptake of Gold Nanoparticles by 2 Species of Tadpole, the Wood Frog (Lithobates Sylvaticus) and the Bullfrog (Lithobates Catesbeianus)

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    Engineered nanoparticles are aquatic contaminants of emerging concern that exert ecotoxicological effects on a wide variety of organisms. We exposed cetyltrimethylammonium bromide–capped spherical gold nanoparticles to wood frog and bullfrog tadpoles with conspecifics and in combination with the other species continuously for 21 d, then measured uptake and localization of gold. Wood frog tadpoles alone and in combination with bullfrog tadpoles took up significantly more gold than bullfrogs. Bullfrog tadpoles in combination with wood frogs took up significantly more gold than controls. The rank order of weight-normalized gold uptake was wood frogs in combination \u3e wood frogs alone \u3e bullfrogs in combination \u3e bullfrogs alone \u3e controls. In all gold-exposed groups of tadpoles, gold was concentrated in the anterior region compared with the posterior region of the body. The concentration of gold nanoparticles in the anterior region of wood frogs both alone and in combination with bullfrogs was significantly higher than the corresponding posterior regions. We also measured depuration time of gold in wood frogs. After 21 d in a solution of gold nanoparticles, tadpoles lost \u3e83% of internalized gold when placed in gold-free water for 5 d. After 10 d in gold-free water, tadpoles lost 94% of their gold. After 15 d, gold concentrations were below the level of detection. Our finding of differential uptake between closely related species living in similar habitats with overlapping geographical distributions argues against generalizing toxicological effects of nanoparticles for a large group of organisms based on measurements in only one species

    Inequality, material well-being, and subjective well-being: Exploring associations for children across 15 diverse countries

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    Children's material well-being, and the levels of wealth and inequality in societies within which children live, are important factors in determining outcomes. However, less is known about the extent to which these factors have an impact children's subjective well-being, especially in an internationally comparative context. This study draws on data from the Children's Worlds survey, an international study of child subjective well-being, to explore links between national level indicators of wealth and inequality (GDP and Gini coefficients), individual indicators of material well-being (the material resources children report having access to), and subjective well-being. The survey covers 15 diverse countries covering the continents of Europe, Asia, Africa and South America, with samples of at least 3000 per country, ages 8, 10 and 12. Analysis takes the form of a multilevel, varying intercepts and slopes model, examining the association between financial and material resources and inequality and subjective well-being across and between countries. Findings suggest that material resources that children report are significantly associated with subjective well-being, while indicators of financial resources and inequality at the national level are not. While a significant association between material resources and subjective well-being is found across the whole sample, the magnitude of this association, and the association between school- and country-level material resources, varies markedly. Within different countries, the strongest material resources-related predictor of overall subjective well-being may be either at the individual, school or country level

    Two-frequency CARS imaging by switching fiber laser excitation

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    This is the peer reviewed version of the following article: Rentchler EC, Xie R, Hui R, JohnsonCK. Two-frequency CARS imaging by switching fiber laser excitation. Microsc Res Tech. 2018;81:413–418. https://doi.org/10. 1002/jemt.22993, which has been published in final form at https://doi.org/10.1002/jemt.22993. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.To fully exploit the power of coherent Raman imaging, techniques are needed to image more than one vibrational frequency simultaneously. We describe a method for switching between two vibrational frequencies based on a single fiber‐laser source. Stokes pulses were generated by soliton self‐frequency shifting in a photonic crystal fiber. Pump and Stokes pulses were stretched to enhance vibrational resolution by spectral focusing. Stokes pulses were switched between two wavelengths on the millisecond time scale by a liquid‐crystal retarder. Proof‐of‐principle is demonstrated by coherent anti‐Stokes Raman imaging of polystyrene beads embedded in a poly(methyl methacrylate) (PMMA) matrix. The Stokes shift was switched between 3,050 cm−1, where polystyrene has a Raman transition, and 2,950 cm−1, where both polystyrene and PMMA have Raman resonances. The method can be extended to multiple vibrational modes

    Effects of extended-release eprinomectin on productivity measures in cow–calf systems and subsequent feedlot performance and carcass characteristics of calves

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    The objective of this study was to estimate the impact of a single injection of extended-release eprinomectin on economically relevant production variables in beef cows and calves as well as subsequent feedlot health, performance, and carcass traits of calves compared with a traditional, short duration anthelmintic. Animals from 13 cooperator herds across seven states were stratified within herd and assigned to one of two treatments; injectable doramectin (DOR; Dectomax; n = 828) or injectable eprinomection (EPR; Longrange; n = 832). Fecal samples were randomly collected from a subset of cows at both treatment and the end of grazing to evaluate fecal egg count (FEC). Continuous and categorical data were analyzed using the MIXED and GLIMMIX procedures of SAS, respectively. Cow treatment body weight (BW) and final BW were not different (P ≥ 0.40) between treatments. There were no differences (P ≥ 0.12) between treatments in cow ADG, change in BW, or body condition scores during the grazing season. While FEC at treatment did not differ (P = 0.18), cows treated with EPR had lower final FEC at the end of the grazing season (P = 0.02) and a greater reduction of FEC over the grazing season (P = 0.01). Calf treatment BW, weaning BW, and ADG did not differ between treatments (P ≥ 0.34). Incidence of pinkeye tended to be less (P = 0.06) for cows treated with EPR but was not different for calves (P = 0.43). Conception to AI, overall pregnancy rates, and calving interval were not different between treatments (P ≥ 0.45). A subset of calves from each herd was sent to Tri-County Steer Carcass Futurity (TCSCF) feedlot for the finishing phase. Calf BW did not differ at initiation of feeding (P = 0.20). While EPR calves tended to be heavier at reimplantation (P = 0.07), final BW and overall ADG were not different between treatments (P ≥ 0.13). Health records indicated lower morbidity for EPR calves (P = 0.05). Carcass performance including HCW, dressing percent, backfat, KPH, REA, YG, were not different between treatment groups (P ≥ 0.12). However, EPR calves had a greater marbling score, greater average quality grade (P \u3c 0.01), and higher proportion of calves that graded average choice or greater (P = 0.03). Results of this study indicate no difference in cow or preweaning calf performance, however, carcass quality in the feedlot phase was improved. Thus, economic analysis indicates opportunities for return on investment if animals treated with EPR have improved health status and/or carcass quality during the feeding phase

    The expression and cellular localization of phospholipase D isozymes in the developing mouse testis

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    To examine the involvement of phospholipase D (PLD) isozymes in postnatal testis development, the expression of PLD1 and PLD2 was examined in the mouse testis at postnatal weeks 1, 2, 4, and 8 using Western blot analysis and immunohistochemistry. The expression of both PLD1 and PLD2 increased gradually with development from postnatal week 1 to 8. Immunohistochemically, PLD immunoreactivity was detected in some germ cells in the testis and interstitial Leydig cells at postnatal week 1. PLD was mainly detected in the spermatocytes and residual bodies of spermatids in the testis after 8 weeks after birth. The intense immunostaining of PLD in Leydig cells remained unchanged by postnatal week 8. These findings suggest that PLD isozymes are involved in the spermatogenesis of the mouse testis
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