Using Statistical Simulation to Visualize and Quantify Day-to-Day Measurement Error in Indirect Calorimetry

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Nervous system differences between the sexes and across the menstrual cycle

Sex hormones have in vitro effects on the nervous system. Furthermore, the effects of estradiol and progesterone metabolites have neurologic responses on the motor system, evidenced by transcranial magnetic stimulation studies. Sex hormone effects on the nervous system may underlie some of the sex discrepancies seen in athletic performance, injury and cardiovascular events. Investigating sex differences is often complicated by hormonal oscillations across the menstrual cycle; therefore, the aims of this research were to investigate sex and menstrual cycle effects on the motor and cardiovascular systems and the interaction of these two systems. In study 1, motor unit (MU) recruitment patterns of the vastus medialis (VM) and vastus medialis oblique (VMO) were examined in males and females at five menstrual cycle phases. Initial discharge rate between the VM and VMO were different only in females. This VM/VMO discharge discrepancy was only evident in females during the ovulatory and mid luteal menstrual phases. Study 2 examined the frequency domain relationship of the VM and VMO MUs between the sexes and across the menstrual cycle. Males have 256% to 741% greater odds of having coherent MU oscillations in the common drive band than females, indicating a greater common rate modulation. Further evidence indicated MU pairs from the VMO and VM/VMO have 228% and 212% greater odds of having beta band oscillations than the VM, indicating control of those muscle groups has a common cortical modulation. Study 3 looked at changes in the autonomic nervous system across the menstrual cycle via heart rate variability analysis. Heart rate variability decreases from the follicular to the luteal phases of the menstrual cycle, indicating a decrease in parasympathetic control. In study 4, the time and frequency domain relationship between electrocardiogram and MU discharge timing was examined between the sexes and across the menstrual cycle. The time domain relationship indicated that both males and females have MU time lag centered between 20-25 milliseconds, with an apparent modulation of this relationship across the menstrual cycle. The findings from this series of studies indicate that there are differences between the sexes which are often modified by the menstrual cycle in females.Kinesiology and Health Educatio

Wettability Gradients On Anodized Aluminum Effects Of Surface Chemical Reactions

Wettability variation of aluminum electrode surfaces was determined using a Wilhemly-type apparatus, in which the pull force exerted by the electrolyte solution on the electrode was measured at each switching of the electrode potential, for a periodically reversed step potential. The data obtained for aluminum and amalgamated electrodes show that metal-liquid surface tension is sensitive to the applied potential mainly through its effect on the chemical composition of the interface. The gradient of wettability induced by chemical reactions generates a displacement of the meniscus during the periodic polarization pulses. Wettability of aluminum surfaces in contact with H2SO4 solutions depends on the acid concentration, in agreement with previous results for iron-sulfuric acid systems.137378178

Pattern Formation On Aluminum Electrodes

The mechanisms of pattern formation on anodized aluminum electrodes in contact with various acid solutions were investigated. The mechanism is related to solute concentration inhomogeneities at the film-solution interface. The size of cells forming the structure was determined experimentally and successfully matched with a recently developed model.13892763277

Dal trailer all'invasione del Sottosopra: le strategie di marketing di Netflix

La tesi si pone come obiettivo quello di esplorare e analizzare le strategie di marketing del colosso over-the-top Netflix, che negli ultimi anni è diventato uno dei principali distributori e produttori di contenuti audiovisivi online a livello globale. Una volta delineato il panorama mediale in cui Netflix opera, si affronterà brevemente la storia della piattaforma OTT per poi introdurre i suoi principali competitor, che negli ultimi anni stanno diventando sempre più numerosi e popolari. Netflix sta ad oggi attuando una strategia di monopolio del settore che determina in modo cruciale quali contenuti vengono prodotti e distribuiti, e come essi vengono di conseguenza promossi. Si analizzeranno quindi le strategie di marketing di Netflix – attraverso l’analisi di casi esemplificativi – facendo particolarmente attenzione a quelle meno convenzionali e più originali, che lo distinguono dai competitor di settore. Degna di nota anche la gestione dei social media, il vero cavallo di battaglia della piattaforma, capace di creare un alto tasso di engagement e fidelizzazione. Partendo quindi da una visione d’insieme della strategia di comunicazione sui social, ci si focalizzerà su ciascuna delle piattaforme più popolari in cui opera per un’analisi più approfondita

Changes in Plasma Potassium During Graded Aerobic Exercise and Two Hours of Recovery

Plasma potassium increases with exercise intensity. Subjects (n=8) were monitored for changes in plasma potas-sium while exercising at progressively increasing steady-state intensities and for two hours of recovery. Plasma po-tassium was significantly increased at 100% of VO2peak compared to 20% and 40% (p<0.01). Plasma potassium at 60 and 120 minutes of recovery from exercise was significantly higher than 6 minutes post exercise (p<0.015). These results support the supposition that high-intensity exercise may lead to hyperkalemia, and also indicates that in-creases in [K + ] occur up to two hours after the cessation of exercise, a newly reported phenomenon. Although, high levels of plasma potassium are known to cause cardiac abnormalities and related events, exercise induced changes in normal healthy adults are not currently believed to have clinical implications

Karakteristik Rengginang Beras Merah (Oryza nivara) - Pati Singkong (Manihot esculenta) Dengan Variasi Lama Penggorengan

Rengginang adalah produk makanan tradisional khas Indonesia yang memiliki rasa gurih, tebal dan bentuknya bulat, umumnya dapat dikonsumsi sebagai pendamping hidangan utama di meja makan atau camilan. Rengginang dalam penelitian ini menggunakan beras merah dan pati singkong dengan variasi lama penggorengan minyak terendam. Kombinasi beras merah dan pati singkong menghasilkan rengginang yang memiliki kandungan serat dan volume pengembangan yang baik. Penelitian ini menggunakan rancangan acak lengkap (RAL) faktorial, yaitu persentase beras merah dan pati singkong serta lama waktu penggorengan. Faktor pertama adalah persentase perbandingan beras merah dan pati singkong yaitu 95:5 ; 90:10 ; 85:15. Faktor kedua adalah lama penggorengan rengginang yaitu 15 detik, 20 detik, dan 25 detik. Pengujian meliputi uji kimia (kadar air, abu, serat pangan total, lemak, protein, karbohidrat by difference), uji fisik (volume pengembangan), dan uji organoleptik (warna, rasa gurih, kerenyahan dan kesukaan keseluruhan). Rengginang terbaik memiliki nilai volume pengembangan tertinggi yaitu 137,51% dan kesukaan keseluruhan tertinggi yaitu 4,40 pada perlakuan persentase beras merah 95% dan pati singkong 5% dalam waktu penggorengan 25 detik, memiliki warna merah cerah kecoklatan, dengan rasa yang gurih, tekstur renyah, dan memiliki kadar air 2,24%, kadar abu 0,59%, kadar serat pangan total 10,42%, kadar lemak 12,79%, kadar protein 8,33%, serta kadar karbohidrat by difference 76,05%

Reserve size and anthropogenic disturbance affect the density of an African leopard (Panthera pardus) meta-population

Determining correlates of density for large carnivores is important to understand their ecological requirements and develop conservation strategies. Of several earlier density studies conducted globally, relatively few addressed a scale (usually >1000 km2) that allows inference on correlates of density over heterogeneous landscapes. We deployed 164 camera trap stations covering ~2500 km2 across five areas characterized by broadly different vegetation cover in the Udzungwa Mountains, Tanzania, to investigate correlates of density for a widespread and adaptable carnivore, the leopard (Panthera pardus). We modelled data in a spatially explicit capture-recapture framework, with both biotic and abiotic covariates hypothesised to influence density. We found that leopard density increased with distance to protected area boundary (mean±SE estimated effect = 0.44±0.20), a proxy for both protected area extent and distance from surrounding human settlements. We estimated mean density at 4.22 leopards/100 km2 (85% CI = 3.33‒5.35/100 km2), with no variation across habitat types. Results indicate that protected area extent and anthropogenic disturbance limit leopard populations whereas no support was found for prey availability and trap array as drivers of leopard density. Such vulnerability is relevant to the conservation of the leopard, which is generally considered more resilient to human disturbance than other large cats. Our findings support the notion that protected areas are important to preserve viable population of leopards, increasingly so in times of unprecedented habitat fragmentation. Protection of buffer zones smoothing the abrupt impact of human activities at reserve edges also appears of critical conservation relevance

Maximal force and tremor changes across the menstrual cycle

PURPOSE: Sex hormones have profound effects on the nervous system in vitro and in vivo. The present study examines the effect of the menstrual cycle on maximal isometric force (MVC) and tremor during an endurance task. METHODS: Nine eumenorrheic females participated in five study visits across their menstrual cycle. In each menstrual phase, an MVC and an endurance task to failure were performed. Tremor across the endurance task was quantified as the coefficient of variation in force and was assessed in absolute time and relative percent time to task failure. RESULTS: MVC decreases 23% from ovulation to the mid luteal phase of the menstrual cycle. In absolute time, the mid luteal phase has the highest initial tremor, though the early follicular phase has substantially higher tremor than other phases after 150 s of task performance. In relative time, the mid luteal phase has the highest level of tremor throughout the endurance task. CONCLUSIONS: Both MVC and tremor during an endurance task are modified by the menstrual cycle. Performance of tasks and sports which require high force and steadiness to exhaustion may be decreased in the mid luteal phase compared to other menstrual phases

Exercise-Induced Glycogen Reduction Increases Muscle Activity

International Journal of Exercise Science 9(3): 336-346, 2016. Intramuscular glycogen stores are an important energy source during extended bouts of strenuous exercise. A substantial reduction in glycogen could influence neural muscular drive and result in a decreasing quality of exercise performance and potentially increased injury rates. The aim of this study was to examine the effect of glycogen reduction on motor drive as determined by the surface electromyogram (EMG) amplitude and median frequency during a cycling graded exercise test. Eight trained cyclists performed a discontinuous cycling graded exercise test to exhaustion under both normal and glycogen reduced conditions. EMG was collected from the vastus lateralis. Repeated measures regression models indicated that EMG amplitudes were elevated at cycling workloads higher than 196 Watts and metabolic workloads higher than 40.8 ml/kg/min, corresponding to 77% VO2max. There was no effect of increases in workload or glycogen reduction on EMG median frequency. Changes in mechanical and metabolic workload had a substantial effect on EMG amplitude (Cohen’s f2 = 0.227 and 0.247, respectively), but not median frequency (Cohen’s f2 = 0.026 and 0.033, respectively). Thus, EMG amplitude is a more effective and reliable measure to examine changes in motor drive during variable workload conditions and metabolic perturbations. The results suggest that healthy glycogen reduced humans require higher levels of muscle activity in order to attain a given mechanical and metabolic workload. This may affect the long term performance of professional and military athletes who need to be able to perform at a high level for extended periods of activity