Daily activity and body temperature

Summary Body temperature varies between 36 and 39° C in states ranging from sleep to high levels of sustained exercise, but it is not known whether this continuum of body temperature is related to a continuum of activity. Calorimetric studies of sedentary days were undertaken with four levels of food intake, men doing mild sustained exercise, and men and women walking and cycling vigorously. Steady states of metabolism were followed by slow exponential changes to steady states of heat loss (Q), followed in turn by changes in rectal temperature (T _re). Regression analysis showed a continuous, curvilinear relationship between Q andT _re from the low end of the activity spectrum (50 W) to progressively higher levels of exercise (600 W). These related continua of activity and body temperature appear to be the result of heat regulation.     

Daily food-anticipatory activity in golden shiners. A test of endogenous timing mechanisms

Shoals of four golden shiners, Notemigonus crysoleucas, were fed daily at a fixed time, which could be the beginning, middle, or end of a 12-h artificial day, or beginning, middle, or end of a 12-h artificial night, depending on the shoal. Almost all shoals showed food-anticipatory activity (FAA), that is, a gradual increase in locomotor activity near the feeder, starting on average 4.5 h before mealtime. FAA started before the time of lights-on or lights-off even in shoals that were fed 1 h after these times. Increases in activity near the feeder generally did not appear at times unrelated to feeding, except for some shoals that were fed around the time of either lights-on or lights-off and that showed high activity at both of those times simultaneously. When food was withheld but the light-dark cycle was preserved, FAA persisted at the old clock time in 78% of the shoals. When the light-dark cycle was eliminated (fish placed in constant darkness), with or without a concurrent removal of the scheduled feeding, FAA persisted at the old clock time in only 22% of the shoals. These results can be explained by a model whereby the animals possess a circadian oscillator that is entrained by the light-dark cycle, with only weak potential for self-sustainability, and where a representation of the normal phase of feeding can be stored in memory. The possibility that FAA was generated by a food-entrainable oscillator can only be reconciled with the data by postulating that this oscillator is normally linked to a light-entrainable oscillator, and that the damping out of the light-entrained oscillator disrupts the action of the food-entrainable one.     

Ethnogenomic diversity of Caucasus, Daghestan.

Autosomal short-tandem repeats (STRs) were typed in ethnic populations of Kubachians, Dargins, Avars, Lezgins, Kumiks, and Nogais of the Caucasus (Daghestan, Russia) at the University of Utah. Daghestan ethnic populations demonstrated differences in STR allele frequency distributions, but these differences were much lower among these ethnic groups compared to worldwide ethnic groups. The observed genetic diversity was low while F(ST) values were high, both of which provided supporting evidence for small population sizes and high levels of isolation among the ethnic groups. An analysis of genetic distance from the three major continents, encompassing Daghestan populations and groups, reveals three distinct clusters: all populations of African affiliation, European and Daghestan populations except the Nogais, and Asian populations with ethnic Nogais.     

Daily differences in patterns of physical activity among overweight/obese children engaged in a physical activity program.

The aim of this study was to compare the physical activity of overweight/obese children during days when they attended a physical activity program, and days when they did not. This is a cross-sectional intervention study of daily physical activity. The participants were referred by family, doctors, or hospital pediatricians to take part in a 10-month interdisciplinary, outpatient obesity intervention program for children. The subjects included 41 overweight and obese children aged 8-16 years, 19 boys (46%) and 22 girls (54%); BMI: 25.7 + 3.3 kg m(-2). The MTI Actigraph was used as an objective measure of daily physical activity over seven consecutive days. Physical activity program days presented a significantly higher percentage of time (4.68%) spent in moderate-to-vigorous activity compared with no physical activity program days (3.16%) and weekend (2.7%). The results of this study suggest that a physical activity program can help increasing daily physical activity in obese children, with a special focus on MVPA level. Our data point that obese children are less active at weekend than during weekdays.     

Daily activity of the rabbit jaw muscles during early postnatal development

Early postnatal development of the jaw muscles is characterized by the transition from suckling to chewing behavior. As chewing develops the jaw closing muscles become more powerful compared with the jaw openers. These changes are likely to affect the amount of daily muscle activity. Therefore, the purpose of this study was to characterize for a jaw opener (digastric) and jaw closer (masseter) the total duration of daily muscle activity (i.e. the duty time), and the daily burst numbers and lengths during early postnatal development. Using radiotelemetry the activity of these muscles was recorded in 10 young New Zealand White rabbits between three and eight weeks of age. Fiber-type composition was analyzed at eight weeks of age by determining the myosin heavy chain content of the fibers. During postnatal development both muscles showed no significant decrease or increase in their daily activity. However, the interindividual variation of the duty time and burst number significantly decreased. There were no significant differences between the digastric and masseter except for the most powerful activities at eight weeks of age, where the masseter showed a significantly higher duty time and burst number than the digastric. The masseter contained a higher number of slow-type fibers expressing myosin heavy chain-I and myosin heavy chain-cardiac alpha than the digastric. The present results suggest that the amount of jaw muscle activation is already established early during postnatal development, before the transition from suckling to chewing behavior. This amount of activation seems to be related to the number of slow-type fibers.     

Phylogeography of Yersinia pestis vole strains isolated from natural foci of the Caucasus and South Caucasus

Comparative analysis of 57 strains of Y. pestis subsp. microtus bv. caucasica was carried out using molecular typing. The results obtained indicate the presence of three independent phylogenetic groups and indicate the advisability of isolation of the Leninakan mountain mesofocus from the Transcaucasian highland focus into an independent focus, as well as inclusion of part of the Pre-Araks low-mountain focus as the mesofocus along with the Pre-Sevan mountain and Zangezur-Karabakh mountain mesofoci into the Transcaucasian highland plague focus. It is shown that the strains circulating in the East Caucasus highland focus of plague are the most ancient branch of the caucasica biovar, and possibly of the entire phylogenetic tree of Y. pestis.     

Daily durations of spontaneous activity in cat’s ankle muscles

 For an understanding of how various degrees of altered use (training, disuse) affect the properties of skeletal muscles, it is important to know how much they are used normally. The main aim of the present project was to produce such background knowledge for hindlimb muscles of the cat. In four adult female cats, each one being studied in several experimental sessions, ankle muscles were chronically implanted with electrodes for electromyographic (EMG) recording. The muscles recorded from were: extensor digitorum longus (EDL), peroneus longus (PL), tibialis anterior (TA), lateral gastrocnemius (LG) and soleus (SOL). For PL, TA and LG, there were anterior as well as posterior recording sites. During 24-h experimental sessions, the studied animal stayed, together with another cat, in a box large enough for playing and walking around. Using telemetric techniques, samples of EMG signals were recorded on tape for 4 min every 30 min. In an off-line analysis, measurements were made of the total accumulated duration of activity from each one of the studied muscle regions. These ”duty times” were expressed as a percentage of total sampling duration. When averaged over the whole 24-h experimental period, the mean duty times per muscle region varied from 1.9% for EDL up to about 13.9% for SOL. Also, among predominantly fast muscles of mixed-fibre composition (i.e. all studied muscles except SOL), marked and statistically significant differences in duty time were found, mean values varying fivefold from 1.9% (EDL) to 9.5% (PL, posterior site). For all three muscles with simultaneous recordings from different sites, consistent and statistically significant differences in daily duty time were found between anterior and posterior regions (anterior less than posterior for TA and PL; anterior more than posterior for LG). We also measured the extent to which each 4-min sampling period was filled with activity (if any). As compared to muscles with a low mean 24-h duty time, those with high duty times were not active during more sampling periods per day, but, whenever being used, their activity lasted relatively longer. Such results were consistent with the view that differences in mean 24-h duty time might largely reflect differences in the extent to which the various muscles and muscle regions were used for long-lasting stabilizing contractions. Received: 15 July 1996 / Accepted: 29 November 1996     

Daily physical activity counts vs structured activity counts in lean and overweight Dutch children

The objectives of this study were to compare daily physical activities, and activities performed according to a structured protocol, measured with tri-axial accelerometers (Tracmor-4), between lean and overweight children. Fourteen overweight children (59.8+/-9.5 kg) and fifteen lean matched controls (47.2+/-8.7 kg) wore the Tracmor-4 daily, during 12+/-1.3 h, for one week in their home environment. Of these, 24 children participated in a sports afternoon, where they performed activities according to the same structured protocol. In addition, physical activity was estimated using a modified Baecke questionnaire. Body composition was determined. Total mean Tracmor counts/day were significantly lower for the overweight children than for the lean (overweight: 46.1+/-6.9 vs. lean: 54.4+/-11.2 kCounts/day, p=0.02), while reported activities (Baecke score) were similar. When performing activities according to the structured protocol, there was no difference in mean Tracmor counts between the two groups (overweight: 36.3+/-6.9 vs. lean: 34.7+/-6.6 kCounts, p=0.6). Daily physical activities were inversely related to percentage body fat (r(2)=0.29, p<0.01); structured activities were not. As compared to lean children, overweight children moved less without being aware of it; yet exerted the same movements per activity. We conclude that in overweight children daily physical activities were reduced and structured activities performed according to instructions were not. In order to prevent progressive overweight or obesity, overweight children should take part in as many as possible structured and scheduled sports activities throughout the week, and be encouraged to behave physically active in daily life.     

Mechanical control of greenhead flies (Diptera: Tabanidae) in a marsh environment.

The effectiveness of New Jersey box traps for the control of adult greenhead flies, Tabanus nigrovittatus, Macquart, T. conterminus Walker, was assessed at Wallops Island, Va. Trap shape and placement were tested. Shallow (0.45 m high) traps caught significantly fewer flies than cubic (0.60 m high) traps. Traps located in the inner two of four layers of traps caught fewer flies than traps in the outer layers.     

Mitochondrial DNA and Y-Chromosome Variation in the Caucasus

We have analyzed mtDNA HVI sequences and Y chromosome haplogroups based on 11 binary markers in 371 individuals, from 11 populations in the Caucasus and the neighbouring countries of Turkey and Iran. Y chromosome haplogroup diversity in the Caucasus was almost as high as in Central Asia and the Near East, and significantly higher than in Europe. More than 27% of the variance in Y‐haplogroups can be attributed to differences between populations, whereas mtDNA showed much lower heterogeneity between populations (less then 5%), suggesting a strong influence of patrilocal social structure. Several groups from the highland region of the Caucasus exhibited low diversity and high differentiation for either or both genetic systems, reflecting enhanced genetic drift in these small, isolated populations. Overall, the Caucasus groups showed greater similarity with West Asian than with European groups for both genetic systems, although this similarity was much more pronounced for the Y chromosome than for mtDNA, suggesting that male‐mediated migrations from West Asia have influenced the genetic structure of Caucasus populations.