Outdoor Season Research Articles

More than Body Composition: A Darwinian Theory of Somatotype, Applied to a DII Track and Field Outdoor Season

More than Body Composition: A Darwinian Theory of Somatotype, Applied to a DII Track and Field Outdoor Season

EVOLUTION OF WOMEN’S HIGH JUMP PERFORMANCE BETWEEN 2011-2020

The study aims to highlight the evolution of the Junior II Women’s high jumpers in the last 10 years at the National Indoor and Outdoor Championships. This study is based on the analysis of the results recorded at the final competitions specific to the Juniors II Women. The final competitions were held in the Lia Manoliu Athletics Hall, Bucharest during the indoor season and at the Lia Manoliu National Stadium in Bucharest and the Trivale Stadium in Pitesti during the outdoor season. The participants of this research were represented by women’s high jumpers from different clubs in the country who joined in the National Championships. All results from the last 10 years were recorded. In conducting the investigation and the research we used: literature study method, pedagogical observation, comparative method, document analysis method, statistical-mathematical method, graphical method. The research hypothesis according to which the results of the junior high jumpers in the last 10 years were progressive was not confirmed. Following this study, we found that the performance of these jumpers was regressive, hence the problem of redesigning the strategy of attracting children to practise athletics events and sustaining them in the training process.

Generic Relationships between Field Uses and Their Geographical Characteristics in Mountain-Area Dairy Cattle Farms

In mountain farms, challenges posed by the degree of land slope, altitude and harsh climate further compound multiple other possible constraints, particularly in relation to the distance of the farm from the farmstead. This study focused on how mountain-area dairy farmers factor the geographical characteristics of their fields into their field-use decisions. To that end, we surveyed 72 farmers who farm the traditional Salers breed of cattle and 28 specialised dairy system farmers in the central Massif region, France. Information was collected on the uses and geographical characteristics of all grassland fields (n = 2341) throughout the entire outdoor grazing season, without identifying farmers’ rationales for their field-use decisions. Field-use classes were constructed for the traditional Salers system per group of fields (grazed-only, cut-only, grazed-and-cut) and then used to classify fields in the specialized dairy system. The geographical characteristics, which were associated afterwards, were significantly different between the field groups and between field-use classes. Grazed-only fields were found to be more sloping and cut-only fields were smaller and further from the farmstead. Distance/area combinations were different according to field use (animal category, earliness of first cut, grazing and cutting sequence) and were decisive for all field-use classes. This study allowed the identification of generic relationships between field uses and their geographical characteristics in mountain-area dairy cattle farms.

Consumption of Two Eggs Daily Increases Serum Leptin in Amenorrheic Runners With Low Energy Availability Without Changes in Lipid Profile

ObjectivesThe primary aim of this study was to investigate the effects of increased dietary cholesterol intake through the consumption of eggs on ovarian sex hormone and leptin levels in amenorrheic female distance athletes. MethodsDivision I female distance runners classified as amenorrheic (AMEN, n = 5) or eumenorrheic (EUMEN, n = 5) via self-report questionnaire participated in this study. Participants consumed two eggs per day for 12 weeks over the course of the outdoor track and field season. EA was calculated at baseline and post-intervention using 3-day dietary records, triaxial accelerometers, and heart rate (HR) monitors. Maximal oxygen uptake (VO2max) was measured to calculate exercise energy expenditure with training HR data. Serum hormones, body composition, and blood lipids were measured at baseline and post-intervention. ResultsThere were no differences exhibited by AMEN and EUMEN groups in body composition, EA, or sex hormones after the dietary intervention. Serum leptin increased in the AMEN group by 70% (P = 0.02) from baseline following egg consumption, while no change in serum leptin was observed in the EUMEN group. EA was calculated to be below 30 kcal·kg–1·FFM·d–1 in both groups following intervention. No changes in serum lipids and lipoprotein cholesterol levels were observed in AMEN or EUMEN due to egg consumption. ConclusionsTwelve-week consumption of two eggs per day increased serum leptin in amenorrheic athletes with low EA with no changes in ovarian sex hormones. The serum lipid profile was not adversely affected by increased dietary cholesterol in the form of eggs. Funding SourcesEgg Nutrition Center Graduate Fellowship Research Grant.

Game Exposure, Player Characteristics, and Neuromuscular Performance Influence Injury Risk in Professional and Youth Field Hockey Players.

Background:Identifying factors that contribute to the occurrence of injury is an important step in designing training programs to minimize the risk of injury. However, despite high injury rates, variables contributing to injury in field hockey players remain relatively unexplored.Purpose:To identify factors that may predict injury in professional and youth field hockey players.Study Design:Cohort study; Level of evidence, 2.Method:Professional and youth hockey players completed preseason neuromuscular performance testing and were monitored for injuries, training, and game exposure throughout the subsequent 12-month indoor and outdoor hockey season. Least absolute shrinkage and selection operator analysis was conducted to identify injury risk factors. Receiver operating characteristic curves were then calculated to determine the individual predictive accuracy of the identified variables.Results:A total of 83 players (mean ± SD age, 20.7 ± 4.9 years; 34.9% female) with complete performance, injury, and exposure data were included for data analysis. Almost half of players (44.6%) sustained a time-loss injury during the season, and 73% of these injuries occurred in the lower limb. Playing more games and having an older age, asymmetrical and poor dynamic postural control, and better explosive performance were identified as jointly influencing the risk of injury. When considered individually, number of games played throughout the season was the most accurate predictor of injury risk (area under the curve [AUC] = 0.74; P < .001), while asymmetrical and poor dynamic postural control (AUCs = 0.61-0.65; P = .01-.04) and better explosive athletic performance (AUCs = 0.65-0.67; P < .01) were identified as moderate individual predictors of sustaining a general or lower limb injury.Conclusion:A number of modifiable factors were individually and jointly associated with an increased injury risk in field hockey players, providing initial evidence for the design of targeted and sport-specific training programs to mitigate the risk of injury.

Load Index and Vertical Jump to Monitor Neuromuscular Fatigue in an Elite 800-m Athlete.

To analyze the relationships between the evolution of training-load values and countermovement jump (CMJ) as an indicator of stress and fatigue in a high-level 800-m runner during a whole season, including indoor (ID) and outdoor season (OD). Over 42weeks, daily training load was quantified as the result of the product of the intensity and volume, and it was termed load index (LI). CMJ was measured in every running session after warm-up and immediately after the last effort of the session. Other jump-related variables such as CMJ height loss, average weekly CMJ, initial CMJ of the next consecutive session, and initial CMJ of the following week were studied. A significant negative relationship was observed between LI and weekly CMJ (ID: r = -.68, P < .001, common variance [CV] = 46%; OD: r = -.73, P < .001, CV = 53%), initial CMJ of the following week (OD: r = -.71, P < .01, CV = 50%), and CMJ height loss (ID: r = -.58, P < .01, CV = 34%; OD: r = -.52, P < .01, CV = 27%). A significant positive relationship was observed between LI and initial CMJ of the next consecutive session when LI values were <8 (OD: r = .72; P < .01, CV = 52%). However, from values ≥8, the relationship turned into a significant negative one (ID: r = -.74; P < .01, CV = 55%; OD: r = -64, P < .01, CV = 41%). CMJ may be a valid indicator of the degree of stress or fatigue generated by specific training sessions of a competitive athlete within a single session, a week, or even the following week. There could be an individual limit LI value from which the training volume does not allow a positive effect on high-speed actions such as a CMJ in the next consecutive session.

Phosphorus load in outdoor areas for laying hens and capacity of phosphorus retaining materials to reduce the environmental impact

This study investigated manure loads in outdoor paddocks for laying hens and the capacity of two phosphorus (P) retaining materials for reducing leaching from manure in areas with high hen density. Inventories on two commercial farms during 2 years (2017 and 2018) of the impact of hens (groups of 3000 hens) on vegetation, as a proxy for land use by hens, showed that 16–21% of outdoor area in grassland paddocks and 22–39% of area in a forest paddock were used by the hens. Sand and limestone were tested as P retention materials in areas with high manure load in a field study during the outdoor season for laying hens (May 1 to October 31 in 2018). The materials were placed on the ground (0.2 m deep bed, 3.3 m wide) outside the pop-hole in paddocks with 76 hens. The average numbers of hens outdoors were recorded at 9 am and 3 pm daily. There was no significant difference between the materials concerning distribution of hens, and they seemed not to prefer any material more than the other. When cylinders containing the spent materials were exposed to simulated rainfalls in a laboratory study, the P concentrations in drainage water were high for all materials, including a control with gravel (58–136 mg PO4-P L−1 and 130–197 mg total-P L−1). On average, 14% of manure P retained in the sand and limestone materials was leached after 100 mm of simulated rainfall. Thus, these materials may act as physical filters for P in manure, but to reduce the risk of P losses to waters during the following winter, they need to be removed from the paddocks and preferably used as potential P fertilizers on arable land.

SOMATOTYPING IN COLLEGE TRACK &amp; FIELD ATHLETES: EVALUATING CHANGE ACROSS A COMPETITIVE SEASON

Coaches may find value in following track and field athletes’ anthropometrics as the extended competitive season requires a unique balance of peak and maintained preparation. Somatotyping may offer a more holistic metric compared with BMI, mass, or body fat percentage alone when tracking changes across competition mesocycles. PURPOSE: The purpose of this study was to record track and field athletes’ somatotype scores to elucidate potential changes across the competitive season according to sex and/or age. METHODS: Division II track and field athletes (n=47) were tested at the start and end of the outdoor season. Somatotype data were collected according to the Heath-Carter manual (skinfolds, girths, breadths, stature & mass). Raw data were converted to mesomorph, endomorph, and ectomorph scores. One-way RM ANOVAs with between subject variables (sex & age) were used to evaluate change in endomorphy, mesomorphy, and ectomorphy scores across the season. RESULTS: Scores for endomorphy (F(1,45)=117.9, p<.001, np2=0.72, males (M)= +3.2%, females (F)= -0.1%) and mesomorphy (F(1,45)=10.1, p=.003, np2=0.18, M= -3.4%, F= +4.6%) differed across time by sex, but not ectomorphy (F(1,52)=0.03, p=.86, np2=0.01, M= -6.2%, F= -6.3%). Age did not influence somatotype scores across the season. CONCLUSIONS: The rigors of a competitive season may influence only certain sex-somatotype combinations. Influencing factors for the divergent changes in somatotype presently found should be identified to optimize training approaches.

CHARACTERIZING PERFORMANCE IN ELITE TRACK AND FIELD SPRINTERS IN RELATION TO THE ACUTE:CHRONIC WORKLOAD RATIO

PURPOSE: The acute:chronic workload ratio is a method of training load quantification that quantifies internal and external responses to training. Chronic training load is a rolling average of the most recent 28 days of training, and the acute workload is the most recent 7 days. The purpose of this study was to explore the relationship between the acute:chronic workload ratio and peak performance in elite track and field sprinters over the course of the 2018 outdoor season. METHODS: The acute:chronic workload ratio was determined retrospectively by calculating the sum of the 7 days before a competition session ratings of perceived exertion of training load (acute load) and dividing it by the average weekly session rating of perceived exertion of training load over the 28-days prior to competition (chronic workload). Partial correlations were used to characterize the relationship between race time (covaried for confounding variables of temperature, humidity, and wind) and the acute:chronic workload ratio. Secondarily, the adjusted race times were used to create Z-scores for each sprinters’ race time. Bins were then created for the acute:chronic workload ratio ranges, and the Z-scores were pooled into the acute:chronic workload ratio bins with which they corresponded. RESULTS: Moderate, positive correlations between the acute:chronic workload ratio and race times for the 100m (r= 0.542) and 200m (r= 0.711) races were observed. 85% of 100m sprinters and 60% of 200m sprinters had their lowest times within the 0.8-1.3 z- score bin: a range cited in previous research as being associated with a lowest risk of injury. CONCLUSIONS: Maintaining an acute:chronic workload ratio between 0.8 and 1.3 may be optimal for elite track and field sprinters to reach their peak performance in the 100m and 200m races. An individualized approach to training load using the acute:chronic workload ratio should help coaches and performance staff with individualized training-load prescription for the sprinters to reach peak performance.

Forage system is the key driver of mountain milk specificity

The aims of this work were to determine the effect of upland origin on milk composition when comparing similar lowland and upland production system and to highlight the factors responsible for the added value of upland milk from commercial farms. Tanker milk from 55 groups of farms (264 farms in total) in France, Slovakia, and Slovenia was collected twice during the indoor season and 3 times during the outdoor season. The tanker rounds were selected in each country to be balanced according to their origin (lowland or upland) and within upland or lowland groups, according to the forage systems: corn-based or grass-based forage system. At each milk sampling, the production conditions were recorded through on-farm surveys. The milk was analyzed for gross composition, carotenoids, minerals, fatty acids, phenolic compound derivatives, volatile organic compound concentrations, and color. The milk from upland and lowland areas differed in their contents of a few constituents. Upland milk was richer in not identified (n.i.) retention time (Rt) 13,59, 4-methylpentylbenzene, 1-methyl-2-n-hexylbenzene, and β-caryophyllene than lowland milk. These differences could be most likely attributable to the utilization of highly diversified and extensively managed semi-natural grasslands. The higher forbs content of upland pastures could be related as well to the richness in C18:3n-3, CLA cis-9,trans-11, MUFA, and PUFA we observed in upland compared with lowland milk during the outdoor season. In contrast, grazing on lowland pastures rich in grasses gave a yellower milk that was richer in β-carotene. Out of the few compounds showing a significant effect of origin or its interaction, most of the milk constituents were unaffected by the origin at all. However, almost all milk constituents differed according to the forage system and the season, and the differences observed between seasons can be attributed to differences in the cow diet composition.

Relationship Between Hepcidin, Interluken-6, And Ferritin In Division-I Cross-country Runners Over A Competitive Season

Iron deficiency, which can be assessed by the iron storage protein ferritin (fer) can negatively affect athletic performance. We have previously observed that Division 1 cross country (XC) runners have fer levels that are at the low end of normal ranges despite being iron supplemented. The hormone hepcidin and the cytokine/myokine interleukin-6 (IL6) can both influence iron regulation but have not been evaluated in this population. PURPOSE: The purpose of this study was to determine how hepcidin and IL6 change over a season in DI XC runners and determine whether changes in these parameters were related to changes in fer, hemoglobin concentration (Hb) or hematocrit (Hct). METHODS: 45 athletes (25 female, 20 male) were recruited from the University of Colorado DI XC team in the fall of 2017. Fasted blood samples were collected in October (before NCAA XC championships), January, and March (during the outdoor track season). Blood samples were analyzed for Hb, Hct, fer, IL6 and hepcidin. All runners were provided with oral iron supplements from a certified nutritionist during this period. RESULTS: All biomarkers remained stable across the season except Hb, which was significantly higher in March. In males vs. females, there were no differences in hepcidin (24 ± 11 vs. 21 ± 11 ng/ml; p > 0.05) or IL6 (16 ± 21 vs. 12 ± 24 pg/mL; p > 0.05). When compared to females, males had higher fer (64 ± 33 vs 47 ± 24 ng/mL; p < 0.05), Hct (48 ± 2 vs 44 ± 3 %; p < 0.001), and Hb (16.3 ± 0.7 vs 14.8 ± 0.8 g/dl; p < 0.01). After controlling for sex, there was a positive relationship between hepcidin and fer (r = 0.47, p < 0.01); 20% of the variability in fer was explained by hepcidin and 51% was explained by individual variability. There were no relationships between IL6 and hepcidin or IL6 and fer. CONCLUSION: Despite a consistent iron supplementation regime, hepcidin, IL6 and fer do not seem to systematically change across a season in collegiate runners. As expected, hepcidin and fer were positively related, but there were no relationships between IL6 and other measured parameters. Although fer was at the low end of normal for both men and women, all other parameters were normal at all time points, suggesting that the normal range of fer for endurance athletes may be lower than the general population.

Tendon structure quantified using ultrasound imaging differs based on location and training type.

Achilles tendinopathy is 10 times more common among running athletes compared with age-matched peers. Load-induced tendon remodeling and its progression in an at-risk population of developing symptomatic tendinopathy are not well understood. The purpose of this study was to prospectively characterize Achilles and patellar tendon structure in competitive collegiate distance runners over different competitive seasons using quantitative ultrasound imaging. Twenty-two collegiate cross-country runners and eleven controls were examined for this study. Ultrasound images of bilateral Achilles and patellar tendons were obtained near the start and end of the collegiate cross-country season and the conclusion outdoor track season. Collagen organization, mean echogenicity, tendon thickness, and neovascularity were determined using well-established image processing techniques. Achilles tendon collagen was less aligned in runners compared with controls (28% greater) but improved slightly (7% decrease) after the completion of the track season. Conversely, patellar tendons in runners were similar to control tendons throughout the cross-country season but underwent collagen alignment (17% decrease) and tendon hypertrophy (21% increase). Our findings indicate that Achilles tendon structure in trained runners differs structurally from control tendons but is stable throughout training while patellar tendon structure changes in response to the transition in training volume between cross-country and track seasons. These findings expand upon prior reports that some degree of tendon remodeling may act as a protective adaptation for sport specific loading.NEW & NOTEWORTHY In this study we prospectively examined the Achilles and patellar tendon structure of distance runners to determine if continued training through multiple seasons elicits tendon remodeling or pathology. We found that Achilles and patellar tendons respond uniquely to the changing loads required during each season. Achilles tendon collagen alignment is mostly stable throughout the competitive cycle, but the patellar tendon structurally remodels following the transition from cross-country to track season.

Epidemiology of injuries in outdoor and indoor hockey players over one season: a prospective cohort study

ObjectivesTo determine the incidence and characteristics of hockey (‘field hockey’) injuries over the course of one outdoor and indoor season. Comparisons of female versus male players, outdoor versus indoor season...

Lighted-weighted model predictive control for hybrid ventilation operation based on clusters of neural network models

Abstract As one of the most significant factors to determine the success of a hybrid ventilation building, the control strategy for the hybrid ventilation operation attracts increasing attentions from both building designers and researchers these years. Recent advancements of the building control strategy have shown the potential to improve the hybrid ventilation operation. In this paper, we demonstrate the development of an advanced data-driven model predictive control (MPC) algorithm, i.e. a light-weighted three phase NN (neural network) model, for controlling the operation of hybrid ventilation buildings. To develop a robust model predictive control algorithm, firstly, different levels of uncertainties that commonly exist in the real world and building simulation are quantified to efficiently train the central model of the MPC and thoroughly test it in the future. In addition, in the model predictive control establishment process, four candidate mathematical models and ten prediction variables were analyzed during the MPC development to investigate its performance on the prediction as well. The results show that the neural network (NN) achieves the best performance considering both prediction performance and computation time. Six variables including the indoor and outdoor air temperature, relative humidity, office and season index and wind speed were finally chosen. At last, we conduct the validation of the algorithm for hybrid ventilation across four cities in different US climates under uncertainties presented in real practice. The comparison between the MPC and the rule-based control clearly presents that the developed MPC could be better at maintaining the thermal comfort of hybrid ventilation buildings while achieving a comparable amount of energy savings.

A Field Study on Climate Comfortable Conditions of Urban Public Open Spaces in Marginal Season of Winter Cities

In order to study the importance of climate comfortable conditions of urban public open spaces in marginal season of winter cities for people's outdoor activities, first, the paper ascertained the specific times of Harbin's outdoor and marginal seasons based on meteorological data from 1984 to 2013. Second, this paper conducted field survey, which includes in situ measurement and structured interview, in three typical urban public open spaces in marginal season. The calculated results show that Harbin has an outdoor season from Apr 25th to Oct 1st, and the spring marginal season is from Apr 4th to Apr 24th, the fall marginal season is from Oct 2nd to Oct 24th. At the same time, the results of in situ measurement show that there is great room for the improvement of climatic conditions of urban public open spaces in the marginal season of winter cities, especially the public open spaces near to the high-rise buildings and waterfront, and the apparent temperature in these two open spaces is about 3°C lower than the air temperature simultaneously. The results of structured interview show that people would like to do some outdoor activities when it is nice weather outside in marginal season, and the regression analysis results show that people's outdoor activities time are severely affected by climate comfortable conditions in marginal season. They feel that fine microclimate is much more important for a person than enough facilities and green landscape of urban public open spaces in marginal season. The paper suggested that the specific times of outdoor and marginal seasons should be added to some urban design guidance as a specification in urban planning practice, and this paper advanced some urban planning strategies related to urban design to improve climatic conditions of urban public open spaces in the marginal seasons of winter cities.

Training of Horses Used for Show Jumping and Its Effect on v4

The training of 19 show jumping horses was documented and related to the changes of v4 during an outdoor season (v4 = speed at which a blood lactate concentration of 4 mmol/L is achieved). Eleven of the horses were managed by a professional trainer (professional show jumpers) and the other horses by amateur riders (amateur show jumpers [ASJs]). All horses were submitted to three standardized exercise tests (SET) to calculate v4: April/May, June/July, and September: SET1, SET2, and SET3. The professional trainer recorded the training from 2 months before SET1 until SET3 and the amateur riders between SET1 and SET3. The duration of the specific exercises such as gymnastics, jumping, and others ranged between 30 and 60 minutes. Professional show jumpers were exercised less often, and the duration of each one of the specific exercises was lower than that for ASJs (P = .01). Considering all horses involved in the study, the v4 increased between SET1 and SET2 when the mean duration of all specific exercises together and of gymnastics only was longer, and the number of days on pasture was greater (P < .05). These relationships were not significant for the separated groups. The v4 of ASJs increased between SET2 and SET3 when horses were kept on pasture for more time (r2 = 0.64). These results give insight in the training of show jumping horses and its effect on v4 and might be useful to improve their training.

Optimal management of replacement heifers in a beef herd: a model for simultaneous optimization of rearing and breeding decisions.

The aim of this study was to provide farmers an efficient tool for supporting optimal decisions in the beef heifer rearing process. The complexity of beef heifer management prompted the development of a model including decisions on the feeding level during prepuberty (age <10 mo), the time of weaning (age, BW, calendar month), the feeding level during the reproductive period (age ≥10 mo), and time of breeding (age, BW, and calendar month). The model was formulated as 3-level hierarchic Markov process. A founder level of the model has 12 states resembling all possible birth months of a heifer. Based on the birth month information from the founder level, for the indoor season (November to April) and outdoor season (May to October), feeding and breeding costs (natural service cost in the outdoor and AI cost in the indoor season) were applied. The optimal rearing strategy was found by maximizing the total discounted net revenues from the predicted future productivity of the Polish Limousine heifers defined as the cumulative BW of calves born from a cow calved until the age of 5 yr, standardized on the 210th day of age. According to the modeled optimal policy, heifers fed during the whole rearing period at the ADG of 810 g/d and generally weaned after the maximum suckling period of 9 mo should already be bred at the age of 13.2 mo and BW constituting 55.6% of the average mature BW. Based on the optimal strategy, 52% of all heifers conceived from May to July and calved from February to April. This optimal rearing pattern resulted in an average net return of EUR 311.6 per pregnant heifer. It was found that the economic efficiency of beef operations can be improved by applying different herd management practices to those currently used in Poland. Breeding at 55.6% of the average mature BW, after a shorter and less expensive rearing period, resulted in an increase in the average net return per heifer by almost 18% compared to the conventional system, in which heifers were bred after attaining 65% of the mature BW. Extension of the rearing period by 2.5 mo (breeding at the age 15.7 mo), due to a prepubertal growth rate lowered by 200 g, reduced the average net return per heifer by 6.2% compared to the results obtained under the basic model assumptions. In the future, the model may also be extended to investigate additional aspects of the beef heifer development, such as the environmental impacts of various heifer management decisions.

Is There a Correlation in Improvements of TOPS Scores and Improvements in Track and Field Performances in Collegiate Athletes?

This presentation will share the results from a study conducted on college track and field athletes at the NCAA division II level. The study compares the results of scores on the Test of Performance Strategies (TOPS) and, individual athlete’s improvements in their event area according to the International Association of Athletics Federation (IAAF) scoring charts for track and field. A select group of primarily middle distance and distance runners was selected for the study. These athletes were given a baseline TOPS examination to evaluate their prior knowledge and use of mental skills in their athletic experiences. Personal best times in the athlete’s primary events were recorded from the previous year. During the nine weeks of the outdoor track and field season that this study took place; athletes were introduced to a wide array of activities associated with improving their mental skills. Such activities included goal setting, imagery, relaxation, optimum level of arousal, affirmations, and the use of positive self-talk and routines. Athletes would have an organized mental skills session at least twice each of the nine weeks of the season. Athletes also had an individual meeting with the coaches to go over goal setting and the use of their mental skills to enhance their physical skills. After the outdoor season was completed the athletes took a post-examination TOPS. The scores were compared with their pretest scores as well as their improvement in personal best times in their main events on the track.

Livestock management at northern latitudes: Potential economic effects of climate change in sheep farming

We study the economy and ecology of sheep farming under future climate change scenarios. The analysis is at the farm level and includes two different categories of the animals, ewes (adult females) and lambs with a crucial distinction between the outdoor grazing season and the winter indoor season. The model is formulated in a Nordic economic and biological setting. During the outdoor grazing season, animals may experience growth constraints as a result of limited grazing resources. The available grazing resources are determined by animal density (stocking rate) and weather conditions potentially affecting the weight, and hence, the value of lambs. Because empirical evidence suggests that climate changes, e.g., increased temperature, have contrasting effects on lamb weights depending on the location of the farm, the spatial effects of such changes are analyzed.

Variability of indoor and outdoor VOC measurements: An analysis using variance components

This study examines concentrations of volatile organic compounds (VOCs) measured inside and outside of 162 residences in southeast Michigan, U.S.A. Nested analyses apportioned four sources of variation: city, residence, season, and measurement uncertainty. Indoor measurements were dominated by seasonal and residence effects, accounting for 50 and 31%, respectively, of the total variance. Contributions from measurement uncertainty (<20%) and city effects (<10%) were small. For outdoor measurements, season, city and measurement variation accounted for 43, 29 and 27% of variance, respectively, while residence location had negligible impact (<2%). These results show that, to obtain representative estimates of indoor concentrations, measurements in multiple seasons are required. In contrast, outdoor VOC concentrations can use multi-seasonal measurements at centralized locations. Error models showed that uncertainties at low concentrations might obscure effects of other factors. Variance component analyses can be used to interpret existing measurements, design effective exposure studies, and determine whether the instrumentation and protocols are satisfactory.