Economic analysis of high-oleic soybeans in dairy rations.

We evaluate the potential economic impact of using high-oleic soybeans (HOS) in dairy rations based on a synthesis of results from 5 prior feeding trials. Milk income less feed costs (MILFC) per cow per day is calculated based on assumed increases in milkfat production and increased cost of rations including HOS. The effects of changes in MILFC are evaluated for herds with different numbers of milking cows, and the total volume of HOS required to support different proportions of US dairy cows is calculated. A dynamic supply-chain model assesses the potential market impacts of increases in butterfat supply. The increase in milkfat from the substitution of 5% of ration dry matter with whole HOS (1.4 kg/cow per day) has the potential to increase MILFC by up to $0.27/cow per day or increase the average value of milk by $0.29/45.4 kg for a cow producing 41 kg/d. Changes in MILFC are highly correlated with the price of butter but were positive for butter prices observed from January 2014 to September 2020. The effects of HOS on MILFC suggest the potential for increases in farm profitability of $33,000/yr for a dairy feeding 500 milking cows. Scaled-up use of HOS by US dairy farmers would increase butterfat supplies and lower the butterfat price to a small extent, but these aggregated effects do not offset the positive effects of MILFC at the farm level.

Whole-body photobiomodulation improves post-exercise recovery but does not affect performance or physiological response during maximal anaerobic cycling.

This study aims to examine the effects of acute whole-body photobiomodulation (wbPBM), applied pre-exercise, on bouts of anaerobic cycling (Wingate) performances. Forty-eight healthy, active males and females participated in this single-blind, randomized, crossover study. Participants visited the laboratory three times to complete repeat (4 ×) Wingate testing, with one week between each visit. All participants completed baseline testing during their first visit and randomly received either the wbPBM or placebo condition before testing on the second visit, followed by the opposite condition on the third visit. There were no significant condition × time interactions for any variable (peak power, average power, power decrement, lactate, heart rate, ratings of perceived exertion, heart rate variability (HRV), root-mean square of differences between R-R intervals (rMSSD), power in the high-frequency range (HF) average, power in the low-frequency range (LF) average, total power, LF/HF, or power in the very-low-frequency range average). A main condition effect was only noted for heart rate, where peak heart rate was significantly higher for wbPBM (145, 141-148 bpm) than placebo (143, 139-146 bpm; p = 0.006) and baseline testing (143, 140-146; p = 0.049) throughout the entire testing session (i.e., collapsed across all timepoints). Furthermore, HRV (rMSSD) the following morning after testing was significantly higher for the wbPBM session compared to placebo (p = 0.043). There were no differences in perceived recovery (p = 0.713) or stress (p = 0.978) scores between wbPBM and placebo. Implementing 20 min of wbPBM immediately prior to maximal bouts of anaerobic cycling did not improve performance (i.e., power output) or physiological responses (e.g., lactate). However, wbPBM elicited the ability to work at a higher heart rate throughout testing and seemed to enhance recovery through improved HRV the following morning.

COVID-19 and the agri-food system in the United States and Canada.

Agri-food supply chains in North America have become remarkably efficient, supplying an unprecedented variety of items at the lowest possible cost. However, the initial stages of the COVID-19 pandemic and the near-total temporary loss of the foodservice distribution channel, exposed a vulnerability that many found surprising. Instead of continued shortages, however, the agri-food sector has since moved back to near normal conditions with prices and production levels similar to those typically observed in years prior to the pandemic. Ironically, the specialization in most food supply chains designed for "just-in-time" delivery to specific customers with no reserve capacity, which led to the initial disruptions, may have also been responsible for its rapid rebound. A common theme in assessing the impacts across the six commodities examined is the growing importance of understanding the whole supply chain. Over the longer term, a continuation of the pandemic could push the supply chain toward greater consolidation of firms and diversification of products given the increasing option value of maintaining flexibility. Other structural changes will be felt through input markets, most notably labour, as the trend toward greater automation will continue to accelerate as a response to meeting concerns about a consistent supply of healthy and productive workers. The economic fall out from the pandemic may lead to greater concentration in the sector as some firms are not able to survive the downturn and changes in consumer food buying behaviour, including movement toward online shopping and enhanced demand for attributes associated with resiliency, such as local. On the other hand, online shopping may provide opportunities for small producers and processors to shorten supply chains and reach customers directly. In the long term, COVID-19 impacts on global commerce and developing country production are more uncertain and could influence poverty reduction. While COVID-19's impacts on North American agriculture should have minimal effect on the Sustainable Development Goals (SDGs) through food prices, the ongoing global trends in trade and agribusiness accelerated by the pandemic are relevant for achievement of the SDGs.

Population-based age adjustment tables for use in occupational hearing conservation programs.

Objective: In occupational hearing conservation programmes, age adjustments may be used to subtract expected age effects. Adjustments used in the U.S. came from a small dataset and overlooked important demographic factors, ages, and stimulus frequencies. The present study derived a set of population-based age adjustment tables and validated them using a database of exposed workers.Design: Cross-sectional population-based study and retrospective longitudinal cohort study for validation.Study sample: Data from the U.S. National Health and Nutrition Examination Survey (unweighted n = 9937) were used to produce these tables. Male firefighters and emergency medical service workers (76,195 audiograms) were used for validation.Results: Cross-sectional trends implied less change with age than assumed in current U.S. regulations. Different trends were observed among people identifying with non-Hispanic Black race/ethnicity. Four age adjustment tables (age range: 18-85) were developed (women or men; non-Hispanic Black or other race/ethnicity). Validation outcomes showed that the population-based tables matched median longitudinal changes in hearing sensitivity well.Conclusions: These population-based tables provide a suitable replacement for those implemented in current U.S. regulations. These tables address a broader range of worker ages, account for differences in hearing sensitivity across race/ethnicity categories, and have been validated for men using longitudinal data.

Potential Utility of a Loaded Treadmill Protocol for Tactical Athletes.

Swearingen, JT, Weiss, LW, Smith, WA, Stephenson, MD, and Schilling, BK. Potential utility of a loaded treadmill protocol for tactical athletes. J Strength Cond Res 32(3): 610-616, 2018-Aerobic capacity is an important variable for tactical athletes, with V[Combining Dot Above]O2max being the most direct way of estimating it in a laboratory setting. A mode-specific protocol involving fixed-weight, torso-borne loads was assessed in the current study. On 4 separate days, 15 men (age 22.1 ± 2.7 years, mass 85.1 ± 10.6 kg, height 179.0 ± 7.7 cm) performed a weighted treadmill walking protocol (2 trials) and a nonweighted treadmill running protocol (2 trials). Both the weighted and nonweighted protocols were reliable, with intraclass correlation coefficient values of 0.79 and 0.87, respectively. V[Combining Dot Above]O2peak values from both protocols were highly correlated (r = 0.90, p < 0.01). However, V[Combining Dot Above]O2peak was higher during the nonweighted protocol (t = 7.547, d = 2.47, p < 0.01). Work rate was calculated for both the last completed stage and stage during which participants reached fatigue. Work rates for both protocols on the last completed stage were similar (t = 1.44, d = 0.83, p = 0.17), although the work rate for the final attempted stage was greater for the weighted-walking protocol (t = 5.85, d = 3.60, p < 0.01). These data suggest a weighted-walking V[Combining Dot Above]O2peak that is highly associated with a running V[Combining Dot Above]O2peak. This test may be applied to those who routinely perform torso-borne load carriage, such as tactical athletes. Future weighted-walking protocols should seek achieve higher resolution, especially near the end stage of the test where subjects reach volitional fatigue. Large increases in work rate may not be feasible at the end stages of the test.

Stimulus and transducer effects on threshold.

OBJECTIVE: This study examined differences in thresholds obtained under Sennheiser HDA200 circumaural earphones using pure tone, equivalent rectangular noise bands, and 1/3 octave noise bands relative to thresholds obtained using Telephonics TDH-39P supra-aural earphones. DESIGN: Thresholds were obtained via each transducer and stimulus condition six times within a 10-day period. STUDY SAMPLE: Forty-nine adults were selected from a prior study to represent low, moderate, and high threshold reliability. RESULTS: The results suggested that (1) only small adjustments were needed to reach equivalent TDH-39P thresholds, (2) pure-tone thresholds obtained with HDA200 circumaural earphones had reliability equal to or better than those obtained using TDH-39P earphones, (3) the reliability of noise-band thresholds improved with broader stimulus bandwidth and was either equal to or better than pure-tone thresholds, and (4) frequency-specificity declined with stimulus bandwidths greater than one equivalent rectangular band, which could complicate early detection of hearing changes that occur within a narrow frequency range. CONCLUSIONS: These data suggest that circumaural earphones such as the HDA200 headphones provide better reliability for audiometric testing as compared to the TDH-39P earphones. These data support the use of noise bands, preferably ERB noises, as stimuli for audiometric monitoring.

Executive Summary From the National Strength and Conditioning Association's Second Blue Ribbon Panel on Military Physical Readiness: Military Physical Performance Testing.

The National Strength and Conditioning Association's tactical strength and conditioning program sponsored the second Blue Ribbon Panel on military physical readiness: military physical performance testing, April 18-19, 2013, Norfolk, VA. This meeting brought together a total of 20 subject matter experts (SMEs) from the U.S. Air Force, Army, Marine Corps, Navy, and academia representing practitioners, operators, researchers, and policy advisors to discuss the current state of physical performance testing across the Armed Services. The SME panel initially rated 9 common military tasks (jumping over obstacles, moving with agility, carrying heavy loads, dragging heavy loads, running long distances, moving quickly over short distances, climbing over obstacles, lifting heavy objects, loading equipment) by the degree to which health-related fitness components (e.g., aerobic fitness, muscular strength, muscular endurance, flexibility, and body composition) and skill-related fitness components (e.g., muscular power, agility, balance, coordination, speed, and reaction time) were required to accomplish these tasks. A scale from 1 to 10 (10 being highest) was used. Muscular strength, power, and endurance received the highest rating scores. Panel consensus concluded that (a) selected fitness components (particularly for skill-related fitness components) are currently not being assessed by the military; (b) field-expedient options to measure both health-based and skill-based fitness components are currently available; and

Short-term variability of pure-tone thresholds obtained with TDH-39P earphones.

OBJECTIVE: To estimate the short-term variability and correlates of variability in pure-tone thresholds obtained using audiometric equipment designed for occupational use, and to examine the justification for excluding 8 kHz as a mandatory threshold in occupational hearing conservation programs. METHOD: Pure-tone thresholds and other hearing-related tests (e.g. noise dosimetry, otoscopy, middle-ear assessment) were conducted with a group of 527 adults between 20 and 69 years of age. Five measurement visits were completed by participants within 14 days. RESULTS: The 50% critical difference boundaries were - 5 and 0 dB at 4 kHz and below and - 5 and 5 dB at 6 and 8 kHz. The likelihood of spurious notches due to test-retest variability was substantially lower than the likelihood of failing to detect a notched configuration when present. Correlates of variability included stimulus frequency, baseline threshold, acoustic reflectance of the ear, average noise exposure during the previous eight hours, age, and the tester's level of education in audiology. CONCLUSION: The short-term variability in 8-kHz pure-tone thresholds obtained with the TDH-39P earphone was slightly greater than at other frequencies, but this difference was not large enough to justify the disadvantages stemming from the inability to detect a 6-kHz notch.

Assessing mercury exposure and biomarkers in largemouth bass (Micropterus salmoides) from a contaminated river system in California.

We evaluated mercury (Hg) exposure and two biomarkers, metallothionein (MT) gene expression and histopathological alterations in a wild fish species, largemouth bass (Micropterus salmoides), collected from the Sacramento-San Joaquin Delta, CA, a region polluted with Hg from historic mining activities. Hg is highly toxic and can disrupt multiple physiological systems in vertebrate species, including the immune system. Total mercury (THg) concentration in muscle tissue ranged from 0.12 to 0.98 ppm (wet weight) and was not related to body condition (r (2) = 0.005, p = 0.555). Using linear regression analysis, we found a positive relationship between MT gene expression (as determined using quantitative polymerase chain reaction) and copper, zinc, manganese, aluminum, and nickel (decreased to one variable by way of principal component analysis) (r (2) = 0.379, p = 0.044), a negative relationship with selenium (r (2) = 0.487, p = 0.017), and a weak, negative relationship with THg concentrations (r (2) = 0.337, p = 0.061). Juvenile largemouth bass collected from Hg-contaminated areas displayed histopathological features of immunosuppression compared with those collected from less contaminated areas as evidenced by significantly lower macrophage density in kidney and liver tissue (p = 0.018 and 0.020, respectively), greater trematode density in liver tissue (p = 0.014), and a greater number of adult trematodes. Our results suggest that largemouth bass may be experiencing sublethal effects from chronic Hg exposure. Furthermore, our findings illustrate the utility of examining multiple sublethal markers of effect to assess the impacts of contaminant exposure on physiological function in wild species.

Effects of vegetation on methylmercury concentrations and loads in a mercury contaminated floodplain.

The Yolo Bypass (YB) is a large flood conveyance system designed to protect the city of Sacramento, California, USA from flooding when the Sacramento River approaches flood stage. The Sacramento River watershed and YB are a source of methylmercury (MeHg) to downstream habitat as a result of historic mercury (Hg) and gold mining practices. In the dry season, the YB is extensively farmed and grazed. However, depending on the water year, the floodplain may remain inundated for months. Our experiments focused on the role of pasture land and decomposing vegetation as a source of MeHg during extensive periods of floodplain flooding. Decomposing vegetation, rather than sediment, was identified as the principal source of filter passing MeHg (fMeHg) within the floodplain. The decomposing vegetation provided a substrate for microbial methylation of inorganic Hg contained within the plants. In replicated flooded mesocosm experiments, MeHg concentrations increased from 2.78 to 31.0 ng g-1 dw and 3.41 to 56.8 ng g-1 dw in decomposing vegetation. In field collections, the concentrations of MeHg in vegetation increased from preflood levels of 2.78 to 45.4 ng g-1 dw after 17 weeks of flooding. The importance of vegetation was shown in laboratory experiments where there was a positive correlation between the amount of fMeHg in water and the amount of vegetation added. These results also provide Hg concentration data for an important functional type of vegetation, grasses, and fill a data gap that contributed to uncertainties with regards to the role of vegetation in Hg cycling.

Evaluating Earplug Performance over a 2-Hour Work Period with a Fit-Test System.

Workers rely on hearing protection devices to prevent occupational noise-induced hearing loss. This study aimed to evaluate changes in attenuation over time for properly fit devices when worn by workers exposed to hazardous noise. Earplug fit testing was accomplished on 30 workers at a brewery facility with three types of foam and three types of premolded earplugs. The personal attenuation ratings (PARs) were measured before and after a 2-hour work period while exposed to hazardous noise levels. The minimum acceptable initial PAR was 15 dB. Average decreases in PAR ranged from -0.7 to -2.6 dB across all six earplug types. Significant changes in PAR were observed for the Foam-1 ( p = 0.009) and Premold-3 ( p = 0.004) earplugs. A linear mixed regression model using HPD type and study year as fixed effects and subject as random effect was not significant for either fixed effect ( α = 0.05). Ninety-five percent of the final PAR measurements maintained the target attenuation of 15 dB. Properly fitting earplugs can be effective at reducing worker's noise exposures over time. The potential for a decrease in attenuation during the work shift should be considered when training workers and establishing the adequacy of protection from hazardous noise exposures.

Typical noise exposure in daily life.

OBJECTIVE: Identify the distribution of typical noise levels present in daily life and identify factors associated with average sound levels. DESIGN: This was an observational study. STUDY SAMPLE: Participants (N = 286) were 20 to 68 year old men and women, drawn from the general population of Kalamazoo County, Michigan. A total of 73 000 person-hours of noise monitoring were conducted. RESULTS: Median overall daily average levels were 79 and 77 dBLeq(A,8,equiv), with average levels exceeding EPA recommended levels for 70% of participants. Median levels were similar between the hours of 9 a.m. and 9 p.m., and varied little across days of the week. Gender, occupational classification, and history of occupational noise exposure were related to average noise levels, but age, educational attainment, and non-occupational noise exposures were not. CONCLUSIONS: A large portion of the general population is exposed to noise levels that could result in long-term adverse effects on hearing. Gender and occupation were most strongly related to exposure, though most participants in this study had occupations that are not conventionally considered noisy.

Effects of Acute Stress on Psychophysiology in Armed Tactical Occupations: A Narrative Review.

The ability to perform under extreme pressure is one of the most sought-after qualities in both sports and tactical (military, law enforcement, fire, and rescue, etc.) occupations. While tactical performance relies on both physical and mental capabilities to achieve a desired outcome, it is often hampered by the stressful environments in which these personnel work. The acute stress experienced by tactical personnel can interfere with occupational performance, impacting both physical execution of tasks and decision-making. This narrative review discusses the implications of acute stress on the psychophysiology and physical performance of personnel serving in armed tactical occupations.

The effect of position on the percentage of body mass supported during traditional and modified push-up variants.

The push-up is a popular upper-extremity weight-bearing exercise. However, limited information is available regarding its effectiveness. Much of the past research has focused on muscle activation levels, whereas very little has examined the forces encountered during push-up variants. The purpose of the present study was to examine the effect of position within the range of motion on the percentage of body mass (BM) supported by the upper extremities during the traditional and modified (knees-down) push-up. Twenty-eight highly strength-trained male subjects were positioned with their hands on a force platform in 4 static positions, consisting of the up and down position in both the traditional and modified push-up exercise. The performance measures included the average vertical ground reaction force (GRF), expressed as a percentage of BM, supported in each of the 4 static positions and the percentage of change between the up and down positions in each push-up exercise. In both the traditional and modified push-ups, subjects supported less weight in the up vs. the down position. The percentage change in % BM from the up to the down position was greater in the modified push-up variant. The pattern of resistances to the push-up exercises observed in this study may be a result of differing moment arms between the support surface contact point (knees or feet) and the hands. These results may be useful in prescribing programs for strengthening and/or rehabilitation for both the prime movers and stabilizers of the upper extremity. Further, range of motion may need to be altered to accommodate strength differences in beginners and clients rehabilitating from injury.

Hearing loss prevention for carpenters: part 1 - using health communication and health promotion models to develop training that works.

In phase 1 of a large multiyear effort, health communication and health promotion models were used to develop a comprehensive hearing loss prevention training program for carpenters. Additionally, a survey was designed to be used as an evaluation instrument. The models informed an iterative research process in which the authors used key informant interviews, focus groups, and early versions of the survey tool to identify critical issues expected to be relevant to the success of the hearing loss prevention training. Commonly held attitudes and beliefs associated with occupational noise exposure and hearing losses, as well as issues associated with the use or non-use of hearing protectors, were identified. The training program was then specifically constructed to positively shape attitudes, beliefs, and behavioral intentions associated with healthy hearing behaviors - especially those associated with appropriate hearing protector use. The goal was to directly address the key issues and overcome the barriers identified during the formative research phase. The survey was finalized using factor analysis methods and repeated pilot testing. It was designed to be used with the training as an evaluation tool and thus could indicate changes over time in attitudes, beliefs, and behavioral intentions regarding hearing loss prevention. Finally, the training program was fine tuned with industry participation so that its delivery would integrate seamlessly into the existing health and safety training provided to apprentice carpenters. In phase 2, reported elsewhere in this volume, the training program and the survey were tested through a demonstration project at two sites.

Hearing loss prevention for carpenters: part 2 - demonstration projects using individualized and group training.

Two demonstration projects were conducted to evaluate the effectiveness of a comprehensive training program for carpenters. This training was paired with audiometry and counseling and a survey of attitudes and beliefs in hearing loss prevention. All participants received hearing tests, multimedia instruction on occupational noise exposure/hearing loss, and instruction and practice in using a diverse selection of hearing protection devices (HPDs). A total of 103 apprentice carpenters participated in the Year 1 training, were given a large supply of these HPDs, and instructions on how to get additional free supplies if they ran out during the 1-year interval between initial and follow-up training. Forty-two participants responded to the survey a second time a year later and completed the Year 2 training. Significant test-retest differences were found between the pre-training and the post-training survey scores. Both forms of instruction (individual versus group) produced equivalent outcomes. The results indicated that training was able to bring all apprentice participants up to the same desired level with regard to attitudes, beliefs, and behavioral intentions to use hearing protection properly. It was concluded that the health communication models used to develop the educational and training materials for this effort were extremely effective.

Effects of training on hearing protector attenuation.

The effect of training instruction, whether presented as the manufacturer's printed instructions, a short video training session specific to the product, or as a one-on-one training session was evaluated using four hearing protection devices with eight groups of subjects. Naïve subjects were recruited and tested using three different forms of training: written, video, and individual training. The group averages for A-weighted attenuation were not statistically significant when compared between the video or the written instruction conditions, regardless of presentation order. The experimenter-trained A-weighted attenuations were significantly greater than the written and video instruction for most of the protectors and groups. For each earplug, the noise reduction statistic for A-weighting (NRS A ) and the associated confidence intervals were calculated for the 80 th and 20 th percentiles of protection. Across subject groups for each protector, the differences between NRS A ratings were found to be not statistically significant. Several comparisons evaluating the order of testing, the type of testing, and statistical tests of the performance across the groups are presented.

Applying Heart Rate Variability to Monitor Health and Performance in Tactical Personnel: A Narrative Review.

Human performance optimization of tactical personnel requires accurate, meticulous, and effective monitoring of biological adaptations and systemic recovery. Due to an increased understanding of its importance and the commercial availability of assessment tools, the use of heart rate variability (HRV) to address this need is becoming more common in the tactical community. Measuring HRV is a non-invasive, practical method for objectively assessing a performer's readiness, workload, and recovery status; when combined with additional data sources and practitioner input, it provides an affordable and scalable solution for gaining actionable information to support the facilitation and maintenance of operational performance. This narrative review discusses the non-clinical use of HRV for assessing, monitoring, and interpreting autonomic nervous system resource availability, modulation, effectiveness, and efficiency in tactical populations. Broadly, HRV metrics represent a complex series of interactions resulting from internal and external stimuli; therefore, a general overview of HRV applications in tactical personnel is discussed, including the influence of occupational specific demands, interactions between cognitive and physical domains, and recommendations on implementing HRV for training and recovery insights into critical health and performance outcomes.

Assessing the Accuracy of Popular Commercial Technologies That Measure Resting Heart Rate and Heart Rate Variability.

Commercial off-the shelf (COTS) wearable devices continue development at unprecedented rates. An unfortunate consequence of their rapid commercialization is the lack of independent, third-party accuracy verification for reported physiological metrics of interest, such as heart rate (HR) and heart rate variability (HRV). To address these shortcomings, the present study examined the accuracy of seven COTS devices in assessing resting-state HR and root mean square of successive differences (rMSSD). Five healthy young adults generated 148 total trials, each of which compared COTS devices against a validation standard, multi-lead electrocardiogram (mECG). All devices accurately reported mean HR, according to absolute percent error summary statistics, although the highest mean absolute percent error (MAPE) was observed for CameraHRV (17.26%). The next highest MAPE for HR was nearly 15% less (HRV4Training, 2.34%). When measuring rMSSD, MAPE was again the highest for CameraHRV [112.36%, concordance correlation coefficient (CCC): 0.04], while the lowest MAPEs observed were from HRV4Training (4.10%; CCC: 0.98) and OURA (6.84%; CCC: 0.91). Our findings support extant literature that exposes varying degrees of veracity among COTS devices. To thoroughly address questionable claims from manufacturers, elucidate the accuracy of data parameters, and maximize the real-world applicative value of emerging devices, future research must continually evaluate COTS devices.