scholarly journals Seasonal and age related changes in size of reproductive structures of red deer hinds (Cervus elaphus)

Rangifer ◽  
1992 ◽  
Vol 12 (3) ◽  
pp. 57 ◽  
Author(s):  
Rolf Langvatn
Keyword(s):  
Cervus Elaphus ◽  
Ovarian Follicle ◽  
Reproductive Status ◽  
Opposite Pattern ◽  
Follicle Diameter ◽  
Age Related ◽  
Cycle Maximum ◽  
Follicle Size ◽  
Low Levels ◽  
And Performance

Morphometric studies of uteri, ovary weights, and follicle diameters were carried out to investigate possible methodological applications. Size and anatomical appearance of the uterus varied with age and phase in the estrous cycle, both in parous and nulliparous females. The uterus thus may provide valuable information on reproductive status for known-aged animals. Weight of ovaries increased in young, but declined in old females, showing significant covariance with body weight in young and prime ages. Ovary weights increased from low levels shortly after parturition to a maximum towards the end of the gestation period. Ovaries containing a corpus luteum were heavier than those without. Compared to ovary weights, mean diameter of largest ovarian follicle varied in an opposite pattern during the yearly cycle. Maximum follicle diameter was largest in non-ovulated females. Weight of ovaries and follicle size appear to be of limited value as criteria in analysis of reproductive status and performance.

scholarly journals Ovarian Follicle Growth during Lactation Determines the Reproductive Performance of Weaned Sows

Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1012 ◽  
Author(s):  
Tania P. Lopes ◽  
Lorena Padilla ◽  
Alfonso Bolarin ◽  
Heriberto Rodriguez-Martinez ◽  
Jordi Roca
Keyword(s):  
Reproductive Performance ◽  
Post Partum ◽  
Ovarian Follicle ◽  
Transrectal Ultrasound ◽  
Great Variability ◽  
Early Lactation ◽  
Follicle Growth ◽  
Follicle Diameter ◽  
Follicular Size ◽  
Follicle Size

Factors causing variability in ovarian follicle size among weaned sows are not well known. This field study aimed to disclose influencing factors and evaluate if the differences at weaning were established during lactation. Ovaries were scanned using transrectal ultrasound. The first experiment was conducted over a year with 191 randomly chosen sows that were hierarchically grouped (p < 0.001) according to ovarian follicle diameter reached at weaning: Small (0.20–0.30 cm; n = 37), medium (0.31–0.39 cm; n = 75), and large (0.40-1.00 cm; n = 69). Sows with small follicles showed a higher incidence of post-weaning anestrus (p < 0.01), longer wean-to-estrus/ovulation intervals (p < 0.01) and farrowing smaller litters (p < 0.05). Ovaries with small follicles were more common among sows weaned in summer–autumn than in winter–spring (p < 0.01) and among sows of lower parity (1–3) (p < 0.05). In the second experiment, with 40 sows randomly chosen at farrowing, the ovaries were scanned at 7, 14, and 21 d post-partum. Sows showed great variability in ovarian follicular size during lactation with a consistent relationship between the three measurement times (r = 0.84, p < 0.01). Follicle size was smaller in sows nursing in summer–autumn than in winter–spring (p < 0.05). In conclusion, early lactation dictates the great variability in ovarian follicular diameter at weaning shown by sows. Sows with smaller follicles at weaning had longer intervals for estrus and ovulation and smaller litters at farrowing and they were in greater numbers among sows weaned during the summer and fall and among those with fewer previous farrowing.

Cognitive Factors Mediate the Relation Between Age and Flight Path Maintenance in General Aviation

2016 ◽  
Vol 6 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Kathleen Van Benthem ◽  
Chris M. Herdman
Keyword(s):  
Cognitive Functioning ◽  
Flight Path ◽  
General Aviation ◽  
Cognitive Factors ◽  
Pilot Performance ◽  
Pilot Error ◽  
Age Related ◽  
And Performance ◽  
Relationship Of ◽  
The Relationship

Abstract. Identifying pilot attributes associated with risk is important, especially in general aviation where pilot error is implicated in most accidents. This research examined the relationship of pilot age, expertise, and cognitive functioning to deviations from an ideal circuit trajectory. In all, 54 pilots, of varying age, flew a Cessna 172 simulator. Cognitive measures were obtained using the CogScreen-AE ( Kay, 1995 ). Older age and lower levels of expertise and cognitive functioning were associated with significantly greater flight path deviations. The relationship between age and performance was fully mediated by a cluster of cognitive factors: speed and working memory, visual attention, and cognitive flexibility. These findings add to the literature showing that age-related changes in cognition may impact pilot performance.

Effects of control strategy on the activation of unwanted intrusive thoughts

2020 ◽  
Author(s):  
Sicong Liu ◽  
Jonathan Folstein ◽  
Lawrence Gregory Appelbaum ◽  
Gershon Tenenbaum
Keyword(s):  
Control Strategies ◽  
Working Memory Capacity ◽  
Intrusive Thoughts ◽  
Control Process ◽  
Event Related Potentials ◽  
Human Beings ◽  
Opposite Pattern ◽  
Thought Control ◽  
Related Potentials ◽  
And Performance

Although the unwanted intrusive thoughts (UITs) exist widely in human beings and show similar characteristics between clinical and nonclinical forms, its control process remains unclear. Thoughts of choking under pressure, particularly among high-achieving athletes, represent a meaningful UIT type due to their psychological and performance-related impact. Taking a dynamic view of UIT control process, this study tested the effect of thought-control strategies among sub-elite to elite athletes, applied to individualized choking thoughts. Ninety athletes recollected recent athletic choking experiences prior to being randomized into one of three thought control interventions using strategies of either acceptance, passive monitoring (control), or suppression. To control for individual differences, athletes’ working memory capacity was measured and modeled as a covariate at baseline. The activation of choking thoughts during and after the intervention was gauged through multiple measurement approaches including conscious presence in mind, priming, and event-related potentials (P3b and N400 amplitudes). Results indicated that, relative to the control, suppression led to enhanced priming and reduced conscious presence of choking thoughts, whereas acceptance resulted in an opposite pattern of reduced priming and increased conscious presence of choking thoughts. In addition, thought-related stimuli elicited less negative-going N400 amplitudes and more positive-going P3b amplitudes than control stimuli. These findings advance understandings of the control mechanism underpinning UITs, and generate applied implications regarding UIT control in high-risk populations such as those with athletic expertise.

Entrepreneurs and Burnout. How Hardy Pesonality works in this process

2021 ◽  
pp. 003329412199697
Author(s):  
Laura Quiun ◽  
Marta Herrero ◽  
Maria del Carmen Yeo Ayala ◽  
Bernardo Moreno-Jiménez
Keyword(s):  
Emotional Exhaustion ◽  
Descriptive Analysis ◽  
Working Hours ◽  
Burnout Syndrome ◽  
Hierarchical Regression ◽  
Occupational Factors ◽  
Low Levels ◽  
And Performance ◽  
The Impact ◽  
The Relationship

Background Considering the importance of entrepreneurship and the impact of burnout on workers’ health, this study aims to explore the presence of burnout in entrepreneurs and the interaction of hardy personality (HP) in this process. Method The sample included 255 Spanish entrepreneurs. Occupational factors, working hours, labour immersion, HP, burnout syndrome (i.e. Emotional exhaustion, Depersonalization and Lack of accomplishment) and burnout consequences were assessed. Results Descriptive analysis showed that entrepreneurs had low levels of occupational factors, burnout syndrome and consequences. Hierarchical regression exploratory results indicated that working hours, labour immersion, and Emotional exhaustion were the most relevant predictors of the consequences. Besides, mediation models with PROCESS macro (v.3.0) highlighted the indirect effect of occupational factors and showed that emotional exhaustion was the only component of burnout that mediated in between the predictors and the consequences. As well, HP moderated the relationship between occupational factors and emotional exhaustion. Conclusions Occupational factors are the main predictor of burnout in entrepreneurs and HP could prevent their effect on Emotional exhaustion. The results suggest the importance of training to promote HP for better health and performance of entrepreneurs.

scholarly journals Self-regulated learning as a predictor of mathematics and reading performance: A picture of students in Grades 5 to 8

2019 ◽  
Vol 63 (1) ◽  
pp. 74-97 ◽  
Author(s):  
Susan-Marie Harding ◽  
Narelle English ◽  
Nives Nibali ◽  
Patrick Griffin ◽  
Lorraine Graham ◽  
...  
Keyword(s):  
Reading Comprehension ◽  
Reading Performance ◽  
Learning Skills ◽  
Self Regulated Learning ◽  
Performance Differences ◽  
Age Related ◽  
Regulated Learning ◽  
And Performance ◽  
The Impact ◽  
Learning And Performance

Students who can regulate their own learning are proposed to gain the most out of education, yet research into the impact of self-regulated learning skills on performance shows mixed results. This study supports the link between self-regulated learning and performance, while providing evidence of grade- or age-related differences. Australian students from Grades 5 to 8 completed mathematics or reading comprehension assessments and self-regulated learning questionnaires, with each response ranked on a hierarchy of quality. All assessments were psychometrically analysed and validated. In each cohort and overall, higher performing students reported higher levels of self-regulated learning. Still, age-related differences outweighed performance differences, resulting in significantly lower reported usage of self-regulated learning skills in Grade 7 students compared to those in Grades 5, 6 and 8. These findings suggest that either age or school organisational differences mediate students’ self-regulated learning, counteracting ability-related associations.

Development of the first urinary reproductive hormone ranges referenced to independently determined ovulation day

2015 ◽  
Vol 53 (7) ◽  
Author(s):  
Sarah Johnson ◽  
Sarah Weddell ◽  
Sonya Godbert ◽  
Guenter Freundl ◽  
Judith Roos ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Hormone Level ◽  
Ovarian Follicle ◽  
Reproductive Hormone ◽  
Fertility Status ◽  
Daily Urine ◽  
Follicle Size ◽  
Status Information ◽  
Progesterone Metabolite ◽  
Level Analysis

AbstractUrinary hormone level analysis provides valuable fertility status information; however, previous studies have not referenced levels to the ovulation day, or have used outdated methods. This study aimed to produce reproductive hormone ranges referenced to ovulation day determined by ultrasound.Women aged 18–40 years (no reported infertility) collected daily urine samples for one complete menstrual cycle. Urinary luteinising hormone (LH), estrone-3-glucuronide (E3G, an estradiol metabolite), follicle stimulating hormone (FSH) and pregnanediol-3-glucuronide (P3G, a progesterone metabolite) were measured using previously validated assays. Volunteers underwent trans-vaginal ultrasound every 2 days until the dominant ovarian follicle size reached 16 mm, when daily scans were performed until ovulation was observed. Data were analysed to create hormone ranges referenced to the day of objective ovulation as determined by ultrasound.In 40 volunteers, mean age 28.9 years, urinary LH surge always preceded ovulation with a mean of 0.81 days; thus LH is an excellent assay-independent predictor of ovulation. The timing of peak LH was assay-dependent and could be post-ovulatory; therefore should no longer be used to predict/determine ovulation. Urinary P3G rose from baseline after ovulation in all volunteers, peaking a median of 7.5 days following ovulation. Median urinary peak E3G and FSH levels occurred 0.5 days prior to ovulation. A persistent rise in urinary E3G was observed from approximately 3 days pre- until 5 days post-ovulation.This study provides reproductive hormone ranges referenced to the actual day of ovulation as determined by ultrasound, to facilitate examination of menstrual cycle endocrinology.

scholarly journals Physical activity in elderly

2015 ◽  
Vol 25 (4) ◽  
pp. 249 ◽  
Author(s):  
Jan Cvecka ◽  
Veronika Tirpakova ◽  
Milan Sedliak ◽  
Helmut Kern ◽  
Winfried Mayr ◽  
...  
Keyword(s):  
Physical Activity ◽  
Electrical Stimulation ◽  
Muscle Mass ◽  
Irreversible Process ◽  
Significant Decline ◽  
Positive Effects ◽  
Age Related ◽  
And Performance ◽  
And Function ◽  
Age Related Changes

Aging is a multifactorial irreversible process associated with significant decline in muscle mass and neuromuscular functions. One of the most efficient methods to counteract age-related changes in muscle mass and function is physical exercise. An alternative effective intervention to improve muscle structure and performance is electrical stimulation. In the present work we present the positive effects of physical activity in elderly and a study where the effects of a 8-week period of functional electrical stimulation and strength training with proprioceptive stimulation in elderly are compared.

Age-related differences in affective and cognitive empathy: self-report and performance-based evidence

2017 ◽  
Vol 25 (5) ◽  
pp. 655-672 ◽  
Author(s):  
Binghai Sun ◽  
Zhenbing Luo ◽  
Wenwen Zhang ◽  
Weijian Li ◽  
Xinyu Li
Keyword(s):  
Cognitive Empathy ◽  
Self Report ◽  
Age Related ◽  
And Performance

Reproductive senescence in free-ranging North American elk Cervus elaphus Cervidae

Mammalia ◽  
2019 ◽  
Vol 83 (6) ◽  
pp. 593-600 ◽  
Author(s):  
Louis C. Bender ◽  
Jessica R. Piasecke
Keyword(s):  
Age Structure ◽  
Cervus Elaphus ◽  
North American ◽  
Reproductive Senescence ◽  
Female Age ◽  
North American Elk ◽  
Age Related ◽  
Consistent Manner ◽  
Multiple Species ◽  
Free Ranging

Abstract Successful production of calves is necessary for growth of North American elk (Cervus elaphus Linnaeus 1758) populations, but few studies have evaluated age-related effects on both the conception and survival of a calf to weaning in multiple free-ranging populations. Conception and survival of calves to weaning were both affected by maternal age, with old (age 9 and older) females showing reproductive senescence as compared to prime-aged (ages 2–8) females despite achieving similar or greater size and condition. Reproductive senescence in our free-ranging populations ultimately resulted in old females weaning fewer calves (0.42 calves/female) than did prime-aged females (0.64 calves/female). Other factors, especially maternal size, also influenced conception and survival to weaning, and these interacted with age in a consistent manner, i.e. larger females or females in better condition were more likely to conceive and successfully wean calves within each age class. Female age structure receives less consideration in ungulate management than does male age structure, despite demonstrated impacts on population productivity of multiple species because of reproductive senescence. Because of the large proportion of individuals in senesced age classes in elk populations, low productivity in populations may simply reflect female age structure, rather than other frequently hypothesized factors.

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