567 research outputs found
Microgravity-Induced Transcriptome Adaptation in Mouse Paraspinal longissimus dorsi Muscle Highlights Insulin Resistance-Linked Genes
Gene expression profiling in slow-Type calf soleus muscle of 30 days space-flown mice
Microgravity exposure as well as chronic disuse are two main causes of skeletal muscle atrophy in animals and humans. The antigravity calf soleus is a reference postural muscle to investigate the mechanism of disuse-induced maladaptation and plasticity of human and rodent (rats or mice) skeletal musculature. Here, we report microgravity-induced global gene expression changes in space-flown mouse skeletal muscle and the identification of yet unknown disuse susceptible transcripts found in soleus (a mainly slow phenotype) but not in extensor digitorum longus (a mainly fast phenotype dorsiflexor as functional counterpart to soleus). Adult C57Bl/N6 male mice (n = 5) flew aboard a biosatellite for 30 days on orbit (BION-M1 mission, 2013), a sex and age-matched cohort were housed in standard vivarium cages (n = 5), or in a replicate flight habitat as ground control (n = 5). Next to disuse atrophy signs (reduced size and myofiber phenotype I to II type shift) as much as 680 differentially expressed genes were found in the space-flown soleus, and only 72 in extensor digitorum longus (only 24 genes in common) compared to ground controls. Altered expression of gene transcripts matched key biological processes (contractile machinery, calcium homeostasis, muscle development, cell metabolism, inflammatory and oxidative stress response). Some transcripts (Fzd9, Casq2, Kcnma1, Ppara, Myf6) were further validated by quantitative real-time PCR (qRT-PCR). Besides previous reports on other leg muscle types we put forth for the first time a complete set of microgravity susceptible gene transcripts in soleus of mice as promising new biomarkers or targets for optimization of physical countermeasures and rehabilitation protocols to overcome disuse atrophy conditions in different clinical settings, rehabilitation and spaceflight
Electrocortical Evidence for Impaired Affective Picture Processing after Long-Term Immobilization
The neurobehavioral risks associated with spaceflight are not well understood. In particular, little attention has been paid on the role of resilience, social processes and emotion regulation during long-duration spaceflight. Bed rest is a well-established spaceflight analogue that combines the adaptations associated with physical inactivity and semi-isolation and confinement. We here investigated the effects of 30 days of 6 degrees head-down tilt bed rest on affective picture processing using event-related potentials (ERP) in healthy men. Compared to a control group, bed rest participants showed significantly decreased P300 and LPP amplitudes to pleasant and unpleasant stimuli, especially in centroparietal regions, after 30 days of bed rest. Source localization revealed a bilateral lower activity in the posterior cingulate gyrus, insula and precuneus in the bed rest group in both ERP time frames for emotional, but not neutral stimuli
Reconstruction of body cavity volume in terrestrial tetrapods
tracts required for the digestion of plant fiber, this concept has not been addressed quantitatively. We estimated the volume of the torso in 126 terrestrial tetrapods (synapsids including basal synapsids and mammals, and diapsids including birds, non-avian dinosaurs and reptiles) classified as either herbivore or carnivore in digital models of mounted skeletons, using the convex hull method. The difference in relative torso volume between diet types was significant in mammals, where relative torso volumes of herbivores were about twice as large as that of carnivores, supporting the general hypothesis. However, this effect was not evident in diapsids. This may either reflect the difficulty to reliably reconstruct mounted skeletons in non-avian dinosaurs, or a fundamental difference in the bauplan of different groups of tetrapods, for example due to differences in respiratory anatomy. Evidently, the condition in mammals should not be automatically assumed in other, including more basal, tetrapod lineages. In both synapsids and diapsids, large animals showed a high degree of divergence with respect to the proportion of their convex hull directly supported by bone, with animals like elephants or Triceratops having a low proportion, and animals such as rhinoceros having a high proportion of bony support. The relevance of this difference remains to be further investigated
The Gender Factor
Purpose Antarctic residence holds many challenges to human physiology, like
increased psycho-social tension and altered circadian rhythm, known to
influence sleep. We assessed changes in sleep patterns during 13 months of
overwintering at the German Stations Neumayer II and III from 2008 to 2014,
with focus on gender, as many previous investigations were inconclusive
regarding gender-based differences or had only included men. Materials &
Methods Time in bed, sleep time, sleep efficiency, number of arousals, sleep
latency, sleep onset, sleep offset, and physical activity level were
determined twice per month during seven overwintering campaigns of n = 54
participants (37 male, 17 female) using actimetry. Data were analyzed using
polynomial regression and analysis of covariance for change over time with the
covariates gender, inhabited station, overwintering season and influence of
physical activity and local sunshine radiation. Results We found overall
longer times in bed (p = 0.004) and sleep time (p = 0.014) for women. The
covariate gender had a significant influence on time in bed (p<0.001), sleep
time (p<0.001), number of arousals (p = 0.04), sleep latency (p = 0.04), and
sleep onset (p<0.001). Women separately (p = 0.02), but not men (p = 0.165),
showed a linear increase in number of arousals. Physical activity decreased
over overwintering time for men (p = 0.003), but not for women (p = 0.174).
The decline in local sunshine radiation led to a 48 minutes longer time in bed
(p<0.001), 3.8% lower sleep efficiency (p<0.001), a delay of 32 minutes in
sleep onset (p<0.001), a delay of 54 minutes in sleep offset (p<0.001), and
11% less daily energy expenditure (p<0.001), for all participants in reaction
to the Antarctic winter’s darkness-phase. Conclusions Overwinterings at the
Stations Neumayer II and III are associated with significant changes in sleep
patterns, with dependences from overwintering time and local sunshine
radiation. Gender appears to be an influence, as women showed a declining
sleep quality, despite that their physical activity remained unchanged,
suggesting other causes such as a higher susceptibility to psycho-social
stress and changes in environmental circadian rhythm during long-term
isolation in Antarctica
Automatic Harvesting for Sweet Peppers in Greenhouse Horticulture
高知工科大学博士(学術) 平成25年3月18日授与(甲第235号)高知工科大学, 博士論文.thesi
The Impact of the Interaction between Verbal and Mathematical Languages in Education
Since the methods employed during teacher-learner interchange are constrained by the internal structure of a discipline, a study of the interaction amongst verbal language, technical language and structure of disciplines is at the heart of the classic problem of transfer in teaching-learning situations. This paper utilizes the analytic method of philosophy to explore aspects of the role of language in mathematics education, and attempts to harmonize mathematical meanings exposed by verbal language and the precise meanings expressed by the mathematics register (MR) formulated in verbal language. While focusing on the integration of language use and meaning construction in mathematics education, the paper explores the relationship between the conceptual understanding revealed by the mathematics register and the procedural knowledge that refers to the mathematical content through ordinary discourse.
Keywords: mathematics register (MR); Mathematics Problem Solving Strategy (MPSS); Mathematical language; Verbal language; conceptual schemata; Text-driven processing; Conceptually-driven processing.
Thought and Practice: A Journal of the Philosophical Association of Kenya (PAK)
New Series, Vol.2 No.2, December 2010, pp.79-99
[email protected] OR [email protected]
http://ajol.info/index.php/tp/inde
Physiological Changes, Activity, and Stress During a 100-km–24-h Walking-March
Background: Long-endurance exercises like ultramarathons are known to elicit various metabolic and physiological changes in the human body. However, little is known about very long-duration exercise at low intensities regarding healthy human subjects.
Aim: The purpose of this study was to evaluate changes in body composition and metabolism in long-endurance but low-intensity events.
Methods: Twenty-five male and 18 female healthy recreational athletes (age 34.6 ± 8.8 years; BMI: 22.4 ± 2.0 kg/m2) of the "100 km Mammutmarsch" were recruited for participation during the events in 2014-2016. Other than classical ultramarathons, the "Mammutmarsch" is a hiking event, in which participants were required to walk but not run or jog. It was expected to complete the 100-km distance within 24 h, resulting in a calculated mean speed of 4.17 km/h, which fits to the mean speed observed (4.12 ± 0.76 km/h). As not all participants reached the finish line, comparison of finishers (FIN, n = 11) and non-finishers (NON, n = 21) allowed differential assessment of performance. Body composition measured through bioelectrical impedance analysis (BIA) was determined pre- and post-event, and serum samples were taken pre-event, at 30, 70, and 100 km to determine NT-pro-BNP, troponin T, C-reactive protein (CRP), cortisol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides, total cholesterol, total creatine kinase (CK), CK-MB, aminotransferase (AST), ALT, and sodium levels. Nineteen participants wore actimeter armbands (SenseWear®) to gain information about body activity and exercise intensity [metabolic equivalent of task (MET)]. Sixteen participants wore mobile heart rate monitors to assess mean heart rate during the race. Serum parameter alterations over the course of the race were analyzed with mixed-effects ANOVA and additional t-tests. All serum parameters were analyzed for correlation concerning different MET levels, speed, age, BMI, baseline NT-pro-BNP, mean heart rate during the race, and sex with linear regression analysis.
Results: We found significant elevations for muscle and cardiac stress markers (CRP, CK, CK-MB, AST, ALT, cortisol, and NT-pro-BNP) as well as decreasing markers of lipid metabolism (cholesterol, triglycerides, LDL). Although the intensity level demanded from our participants was low compared with other studies on (ultra-) marathons, the alteration of tested parameters was similar to those of high-intensity exercise, e.g., NT-pro-BNP showed a fourfold increase (p < 0.01) and LDL decreased by 20% (p = 0.05). Besides the duration of exercise, age, BMI, training status, and sex are relevant parameters that influence the elevation of stress factors. Notably, our data indicate that NT-pro-BNP might be a marker for cardiovascular fitness also in healthy adults.
Conclusion: This low-intensity long-endurance walk evoked a strong systemic reaction and large cell stress and shifted to a favorable lipid profile, comparable to higher intensity events. Despite increasing cardiac stress parameters, there were no indications of cardiac cell damage. Remarkably, the duration seems to have a greater influence on stress markers and metabolism than intensity
Combined protein and calcium β-hydroxy-β-methylbutyrate induced gains in leg fat free mass: a double-blinded, placebo-controlled study
Background The leucine metabolite beta-hydroxy-beta-methylbutyrate (HMB) is widely used as an ergogenic supplement to increase resistance-training induced gains in fat free mass (FFM) and strength in healthy adults. Recent studies have questioned the effectiveness of HMB, particularly when a high protein diet is habitually consumed. To investigate the additive resistance-training induced effects of HMB and protein in untrained individuals, we conducted a randomized double-blind, placebo-controlled study that compared the effects of combined protein and HMB supplementation to protein supplementation alone on FFM and muscle strength after 12-week resistance training. Methods Sixteen healthy men (22 +/- 2 yrs) performed a periodized resistance-training program for twelve weeks (four sessions per week). The program comprised two mesocycles, characterized by a linear periodization and non-linear periodization, respectively, and separated by a 1-week tapering period. All participants received 60 g of whey protein on training days and 30 g of whey protein (WP) on non-training days. Participants were randomly assigned to additionally receive 3 g of calcium HMB (WP + HMB) or a placebo (WP + PLA). Body composition and physical fitness were tested before and after the 12-week training program. Whole-body and arm and leg fat free mass (FFM) were assessed by bioimpedance spectroscopy; upper arm and leg fat free cross sectional areas were also quantified using magnetic resonance imaging (MRI); upper and lower body strength were measured by One-repetition maximum (1-RM) bench press and leg press. Results Whole-body and segmental FFM increased in both groups (P < 0.001). However, gains in leg FFM were higher in WP + HMB vs. WP + PLA (arm FFM: + 6.1% vs. + 9.2%, P = 0.2; leg FFM: + 14.2% vs. + 7.0%, P < 0.01). No change in fat mass was observed (P = 0.59). 1-RM increased in both groups (P < 0.001). Conclusions Combined protein and HMB supplementation resulted in segmental, but not whole-body increases in FFM compared to protein supplementation alone. These findings could explain some of the controversial effects of HMB reported in previous studies and have practical implications for maximizing training-induced gains in FFM and clinical conditions associated with skeletal muscle deconditioning such as aging, sedentary lifestyles, bed rest and spaceflight
Normative leadership: A paradigm for promoting ethical practices in primary teacher education in Kenya
Introduction: Ethical leadership is crucial in all organizations in relation to the successful attainment of institutional vision and mission. However, the influence of morally laden normative leadership on the promotion of ethical practices in primary teacher training colleges in Kenya has not yet been fully analysed and will require further interrogation. This gap is addressed in this study.
Purpose: The study analysed how normative leadership can inspire ethical practices contained in Chapter Six of the Kenyan 2010 constitution, in the context of primary teacher education in Kenya.
Methodology: Within the phenomenological research design, interviews were conducted to answer two questions, related to how normative leadership inspires ethical practices in public primary teachers training colleges (TTC) in Kenya. The purpose-sampling technique was used to select 35 leaders of TTC and seven regional education officers. Thematic analysis was used whereby the coded data was manually analysed on the basis of identified themes and presented in the form of tables and narratives.
Results: The research findings revealed that as role models, normative leaders can succeed in creating a positive ethical environment that institutionalize ethical practices contained in Chapter Six of the Kenyan Constitution to be precise; integrity, discipline, dedication to duty and moral decision making within primary teacher education in Kenya.
Conclusion: This study established that the impact of normative leaders as they demonstrate virtuous behaviour and are positive role models in the context of moral goodness and moral duty could inspire ethical practices within training colleges for teachers.
Recommendation: The study proposed a philosophical paradigm of normative leadership that can positively influence the mind-set of leaders and their subordinates within TTC to internalize ethical practices on the foundation of moral goodness and moral duty
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