Responses to seasonal changes in nutrient quality and patchiness of food in a multigroup community of Tibetan macaques at Mt. Emei

Provisioning along pedestrian trails by tourists much increased the nutrient quality and patchiness of food (NqPF)for Tibetan macaques (Macaca thibetana) at Mt Emei in spring and summer. In the habitat at a temperate-subtropical transition zone, the mncaque's NqPF could be ordered in a decreasing rank from spring summer to autumn to winter With the aid of a radio-tracking system, I collected ranging data on a multigroup community in three 70-day periods representing the different seasons in 1991-92, Rank-order correlation on the data show that with the decline of NqPF; the groups tended to increase days away from the trail, their effective range size (ERS) their exclusive area (EA) and the number of days spent in the EA, and reduced their group/community density and the ratio of the overlapped range to the seasonal range (ROR). In icy/snowy winter; the macaques searched for mature leaves slowly and carefully in the largest seasonal range with a considerable portion that was nor used in other seasons. Of the responses, the ROR decreased with the reduction in group/community density; and the ERS was the function of both group size (+) and intergroup rank (-) when favorite food was highly clumped. All above responses were clearly bound to maximize foraging effectiveness and minimize energy expenditure, and their integration in term of changes in time and space leads to better understanding macaque ecological adaptability. Based on this study and previous work on behavioral and physiological factors, I suggest a unifying theory of intergroup interactions. Ir! addition, as the rate of behavioral interactions,was also related to the group density, I Waser's (1976) gas model probably applies to behavioral, as well as spatial, data on intergroup interactions.

Rhinopithecus bieti at Tacheng, Yunnan: Diet and daytime activities

We collected data on diet and activity budget in a group of Rhinopithecus bieti at Tacheng (99degrees 18'E, 27degrees 36' N, between 2,700 - 3,700 m asl), Yunnan, from March 1999 to December 2000. We mainly recorded species-parts eaten with feeding scores from scanning state behaviors of one-male units in tree-crowns. We also conducted microscopic analysis of feces collected monthly. The subjects consumed 59 plant species, belonging to 42 genera in 28 families, of which 90 species-parts were distributed as follows: 21 in Winter, 38 in spring, 39 in Summer, 47 in autumn. Conversely, the group annually spent, on average, 35% of daytime feeding, 33% resting, 15% moving, and 13% in social activities. Seasonal changes are apparent in daytime budget and food item-related feeding time in tree-crowns, food remains in feces, and the number of species-parts eaten. Correlations within and between food items and time budget clearly indicate maximization of foraging effectiveness and minimization of energy expenditure. In consideration of reports from northern and southern groups, that which underlay the specific adaptation to the habitat appeared to be similar to those of other colobines. Thus, the ultimate factors for survival of the species are more hopeful than expected.

Context-dependent decay of motor memories during skill acquisition.

Current models of motor learning posit that skill acquisition involves both the formation and decay of multiple motor memories that can be engaged in different contexts. Memory formation is assumed to be context dependent, so that errors most strongly update motor memories associated with the current context. In contrast, memory decay is assumed to be context independent, so that movement in any context leads to uniform decay across all contexts. We demonstrate that for both object manipulation and force-field adaptation, contrary to previous models, memory decay is highly context dependent. We show that the decay of memory associated with a given context is greatest for movements made in that context, with more distant contexts showing markedly reduced decay. Thus, both memory formation and decay are strongest for the current context. We propose that this apparently paradoxical organization provides a mechanism for optimizing performance. While memory decay tends to reduce force output, memory formation can correct for any errors that arise, allowing the motor system to regulate force output so as to both minimize errors and avoid unnecessary energy expenditure. The motor commands for any given context thus result from a balance between memory formation and decay, while memories for other contexts are preserved.

Response of cyanobacterial carbon concentrating system to light intensity: a simulated analysis

Cyanobacteria possess a delicate system known as the carbon concentrating mechanism (CCM), which can efficiently elevate the intracellular inorganic carbon (Ci) concentration via active transportation. The system requires energy supplied by photosystems; therefore, the activity of the Ci transporter is closely related to light intensity. However, the relationship between CCM and light intensity has rarely been evaluated. Here, we present an improved quantitative model of CCM in which light is incorporated, and developed a CCM model that modified after Fridlyand et al. in 1996. Some equations used in this model were inducted to describe the relationship between transport capacity and light intensity, by which the response of the CCM to light change is simulated. Our results indicate that the efficiency of the carbon concentrating system is sensitive to light intensity. When the external Ci concentration was low, CO2 uptake dominated the total Ci uptake with increasing light intensity, while under high external Ci concentrations HCO3- uptake primarily contributed to the total Ci uptake. Variations in the ratio of energy allocated between the transport systems could markedly affect the operation of CCM. Indeed, our simulations suggest that various combinations of Ci fluxes can provide a possible approach to detect the way by which the cell distributes energy produced by the photosystems to the two active Ci transport processes. The proportion of the energy consumed on CCM to the total energy expenditure for the fixation of one CO2 molecule was determined at 18%-40%.

Herbal supplements: Recent findings in exercise, health and weight loss

Natural herbs have been in use for weight loss purposes since history began. However, the current global obesity epidemic and the rise in obesity-related chronic diseases, including type-II diabetes and cancer, have highlighted the need for novel and effective approaches for herbal remedies. Whilst the popularity of several prescribed and non-prescribed slimming aids and herbal plant supplements have been marketed for their weight loss efficacy, single and multi-ingredient herbal supplements are still being investigated for their single or combined weight loss benefits. Limited research have highlighted an interesting efficacy for several popular herbal plant supplements including caffeine and capsaicin, Ayurvedic preparations and herbal teas, resulting in various degrees of effectiveness including thermogenic, appetite control and psychological benefits such as mood state. Recent research has suggested acute augmented weight-loss effects of combining herbal ingestion with exercise. For example, ingesting green tea, yerba mate and/or caffeine have been shown to increase metabolic rate, and augmented fatty acid metabolism and to increase energy expenditure from fatty acid sources during exercise with various intensities, particularly at low and moderate intensities. Other promising weight-loss effects have also been also reported for combining exercise with multi-ingredient herbal supplements, particularly those that are rich in phytochemicals and caffeoyl derivatives. Combining herbal ingestions with exercise still require further research in order to establish the supplementation most effective protocols in terms of dosage and timing, and to determine the long-term benefits, particularly those related to exercise protocols, and the long term adherence to sustain the weight loss outcomes.

Open Issues on TCP for Mobile Computing

We discuss the design principles of TCP within the context of heterogeneous wired/wireless networks and mobile networking. We identify three shortcomings in TCP's behavior: (i) the protocol's error detection mechanism, which does not distinguish different types of errors and thus does not suffice for heterogeneous wired/wireless environments, (ii) the error recovery, which is not responsive to the distinctive characteristics of wireless networks such as transient or burst errors due to handoffs and fading channels, and (iii) the protocol strategy, which does not control the tradeoff between performance measures such as goodput and energy consumption, and often entails a wasteful effort of retransmission and energy expenditure. We discuss a solution-framework based on selected research proposals and the associated evaluation criteria for the suggested modifications. We highlight an important angle that did not attract the required attention so far: the need for new performance metrics, appropriate for evaluating the impact of protocol strategies on battery-powered devices.

Longitudinal study of changes in body mass index, anthropometric measures, dietary intake and physical activity in cohorts of school-going Irish adolescents

The prevalence of obesity worldwide has increased dramatically over the last few decades. Poor dietary habits and low levels of exercise in adolescence are often maintained into adulthood where they can impact on the incidence of obesity and chronic diseases. A 3-year longitudinal study of anthropometric, dietary and exercise parameters was carried out annually (2005 - 2007) in 3 Irish secondary schools. Anthropometric measurements were taken in each year and analysed longitudinally. Overweight and obesity were at relatively low levels in these adolescents. Height, weight, BMI, waist and hip circumferences and TST increased significantly over the 3 years. Waist-to-hip ratio (WHR) decreased significantly over time. Boys were significantly taller than girls across the 3 years. A 3-day weighed food diary was used to assess food intake by the adolescents. Analysis of dietary intake data was determined using WISP©. Mean daily energy and nutrient intakes were reported. Mean daily energy and macronutrient intakes were analysed longitudinally. The adolescents’ diet was characterised by relatively high saturated fat intakes and insufficient fruit and vegetable consumption. The dietary pattern did not change significantly over the 3 years. Boys consumed more energy than girls over the study period. A validated questionnaire was used to assess physical activity and sedentary activity levels. Boys were substantially more active and had higher energy expenditure estimates than girls throughout the study. A significant longitudinal decrease in physical activity levels among the adolescents was observed. Both genders spent more than the recommended amount of time (hrs/day) pursing sedentary activities. The dietary pattern in these Irish adolescents is relatively poor. Of additional concern is the overall longitudinal decrease in physical activity levels. Promoting consumption of a balanced diet and increased exercise levels among adolescents will help to reduce future public health care costs due to weight-related diseases.

An examination of the construction of meanings for obesity in Ireland

Obesity has been defined as a consequence of energy imbalance, where energy intake exceeds energy expenditure and results in a build-up of adipose tissue. However, this scientific definition masks the complicated social meanings associated with the condition. This research investigated the construction of meaning around obesity at various levels of inquiry to inform how obesity is portrayed and understood in Ireland. A multi-paradigmatic approach was adopted, drawing on theory and methods from psychology and sociology and an analytical framework combining the Common Sense Model and framing theory was employed. In order to examine the exo-level meanings of obesity, content analysis was performed on two media data sets (n=479, n=346) and a thematic analysis was also performed on the multiple newspaper sample (n=346). At the micro-level, obesity discourses were investigated via the thematic analysis of comments sampled from an online message board. Finally, an online survey assessed individual-level beliefs and understandings of obesity. The media analysis revealed that individual blame for obesity was pervasive and the behavioural frame was dominant. A significant increase in attention to obesity over time was observed, manifestations of weight stigma were common, and there was an emotive discourse of blame directed towards the parents of obese children. The micro-level analysis provided insight into the weight-based stigma in society and a clear set of negative ‘default’ judgements accompanied the obese label. The survey analysis confirmed that the behavioural frame was the dominant means of understanding obesity. One of the strengths of this thesis is the link created between framing and the Common Sense Model in the development of an analytical framework for application in the examination of health/illness representations. This approach helped to ascertain the extent of the pervasive biomedical and individual blame discourse on obesity, which establishes the basis for the stigmatisation of obese persons.

The impact of a variety of factors on the obesity associated gut microbiota

The obesity pandemic has become perhaps the most prevalent health issue of our time, with more than 10% of the world’s population now being obese. Obesity can be defined as abnormal or excess fat accumulation that may impair health and results from an imbalance between energy intake and energy expenditure. A decrease in physical activity due to an increase in sedentary forms of work, changing modes of transport and increasing urbanization is likely a major contributory factor. Diet is another major factor with the increased availability and intake of calorie dense, high fat foods being of global concern. Notably, with respect to this thesis, over the last decade advances in the field of next generation sequencing (NGS) have facilitated investigations to determine the relationship between the gut microbiota and obesity. This thesis examines the impact of a variety of factors on the obesity associated gut microbiota. Overall the results presented in this thesis highlight that microbial diversity is influenced by diet, exercise, antibiotics and disease state, however it is only through further understanding of the structure and function that we can identify targets that can impact on health.

Effect of chronic consumption of almonds on body weight in healthy humans

Small changes of diet may reduce CVD risk. One example is the inclusion of nuts. They are rich in fibre, unsaturated fatty acids and phytonutrients. However, their fat content and energy density raise concerns that chronic consumption will promote weight gain. Randomised intervention studies are required to evaluate whether this concern is well founded. This study's aim was to determine if the inclusion of a 1440 kJ serving of almonds in the daily diet results in positive energy balance, and body composition change. During a 23-week cross-over design study, participants were required to consume almonds for 10 weeks and were provided no advice on how to include them in their diet. For another 10 weeks (order counter-balanced), participants followed their customary diet and there was a 3-week washout between. The study group consisted of twenty women. Potential mechanisms of energy dissipation were measured. Ten weeks of daily almond consumption did not cause a change in body weight. This was predominantly due to compensation for the energy contained in the almonds through reduced food intake from other sources. Moreover, inefficiency in the absorption of energy from almonds was documented (P <0·05). No changes in resting metabolic rate, thermic effect of food or total energy expenditure were noted. A daily 1440 kJ serving of almonds, sufficient to provide beneficial effects on cardiovascular risk factors, may be included in the diet with limited risk of weight gain. Whether this can be generalised to other high-fat energy dense foods warrants evaluation.

Energetics reveals physiologically distinct castes in a eusocial mammal.

Eusociality, which occurs among mammals only in two species of African mole-rat, is characterized by division of labour between morphologically distinct 'castes'1. In Damaraland mole-rats (Cryptomys damarensis), colony labour is divided between 'infrequent worker' and 'frequent worker' castes2. Frequent workers are active year-round and together perform more than 95% of the total work of the colony, whereas infrequent workers typically perform less than 5% of the total work3. Anecdotal evidence suggests that infrequent workers may act as dispersers, with dispersal being limited to comparatively rare periods when the soil is softened by moisture4, 5. Here we show that infrequent workers and queens increase their daily energy expenditure after rainfall whereas frequent workers do not. Infrequent workers are also fatter than frequent workers. We suggest that infrequent workers constitute a physiologically distinct dispersing caste, the members of which, instead of contributing to the work of the colony and helping the queen to reproduce, build up their own body reserves in preparation for dispersal and reproduction when environmental conditions are suitable.

Glycemic State Regulates Brain-Derived Neurotrophic Factor Responsiveness of Neurons in the Paraventricular Nucleus of the Hypothalamus

Brain derived neurotrophic factor (BDNF) is a member of the family of neurotrophins and binds to the tropomyosin-related kinase B (TrkB) receptor. Like other neurotrophic factors, BDNF is involved in the development and differentiation of neurons. Recently, studies have suggested important roles for BDNF in the regulation of energy homeostasis. The paraventricular nucleus (PVN) is critical for normal energy balance contains high levels of both BDNF and TrkB mRNA. Studies have shown that microinjections of BDNF into the PVN increase energy expenditure, suggesting BDNF plays a role in energy homeostasis through direct actions in this hypothalamic nucleus. We used male Sprague-Dawley rats to perform whole-cell current-clamp experiments from PVN neurons in slice preparation. BDNF was bath applied at a concentration of 2nM and caused depolarizations in 54% of neurons (n = 25; mean change in membrane potential: 8.9 ± 1.2 mV), hyperpolarizations in 23% (n = 11; mean change in membrane potential: -6.7 ± 1.4 mV), while the remaining cells tested were unaffected. Previous studies showing effects of BDNF on γ-aminobutyric acid type A (GABAA) mediated neurotransmission in PVN led us to examine if these BDNF-mediated changes in membrane potential were maintained in the presence of tetrodotoxin (TTX) sodium channel blocker (N = 9; 56% depolarized, 22% hyperpolarized, 22% non-responders) and bicuculline (GABAA antagonist) (N = 12; 42% depolarized, 17% hyperpolarized, 41% non-responders), supporting the conclusion that these effects on membrane potential were postsynaptic. We also evaluated the effects of BDNF on these neurons across varying physiologically relevant extracellular glucose concentrations. At 10 mM 23% (n = 11; mean: -6.7 ± 1.4 mV) of PVN neurons hyperpolarized in response to BDNF treatment, whereas at 0.2 mM glucose, 71% showed hyperpolarizing effects (n = 12; mean: -6.3 ± 2.8 mV). Our findings reveal that BDNF has direct impacts on PVN neurons and that these neurons are capable of integrating multiple sources of metabolically relevant input. Our analysis regarding glucose concentrations and their effects on these neurons’ response to other metabolic signals emphasizes the importance of using physiologically relevant conditions for study of central pathways involved in the regulation of energy homeostasis.

Water requirements as a bottleneck in the reintroduction of European roe deer to the southern edge of its range

Success rates of reintroduction programs are low, often owing to a lack of knowledge of site-specific ecological requirements. A reintroduction program of European roe deer (Capreolus capreolus (L., 1758)) in a dry Mediterranean region in Israel provides an opportunity to study the bottleneck effect of water requirements on a mesic-adapted species. Four does were hand-reared and released in a 10 ha site consisting of an early succession scrubland and a mature oak forest. We measured daily energy expenditure (DEE) and water turnover (WTO) using the doubly labeled water technique during summer and winter. DEE was similar in the summer and winter, but there was a significant difference in WTO and in the source of gained water. In winter, WTO was 3.3 L/day, of which 67% was obtained from vegetation. In summer, WTO dropped to 2.1 L/day, of which only 20% was obtained from the diet and 76% was gained from drinking. When the water source was moved to a nonpreferred habitat, drinking frequency dropped significantly, but water consumption remained constant. In a dry Mediterranean environment, availability of free water is both a physiological contraint and a behavioral constraint for roe deer. This study demonstrates the importance of physiological and behavioral feasibility studies for reintroduction programs.

Energetic costs of parasitism in the Cape ground squirrel Xerus inauris

Parasites have been suggested to influence many aspects of host behaviour. Some of these effects may be mediated via their impact on host energy budgets. This impact may include effects on both energy intake and absorption as well as components of expenditure, including resting metabolic rate (RMR) and activity (e.g. grooming). Despite their potential importance, the energy costs of parasitism have seldom been directly quantified in a field setting. Here we pharmacologically treated female Cape ground squirrels (Xerus inauris) with anti-parasite drugs and measured the change in body composition, the daily energy expenditure (DEE) using doubly labelled water, the RMR by respirometry and the proportions of time spent looking for food, feeding, moving and grooming. Post-treatment animals gained an average 19 g of fat or approximately 25 kJ d(-1). DEE averaged 382 kJ d-1 prior to and 375 kJ d-1 post treatment (p> 0.05). RMR averaged 174 kJ d-1 prior to and 217 kJ d-1 post treatment (p

Seasonal energetics of the Hottentot golden mole at 1500m altitude

Winter is an energetically stressful period for small mammals as increasing demands for thermoregulation are often coupled with shortages of food supply. In sub-tropical savannah, Hottentot golden moles (Ambysomus hottentottus longiceps) forage throughout the year and for lone periods of each day. This may enable them to acquire sufficient resources from an insectivorous prey base that is both widely dispersed and energetically costly to obtain. However, they also inhabit much cooler regions; how their energy budgets are managed in these areas is unknown. We measured the daily energy expenditure (DEE), resting metabolic rate (RMR) and water turnover (WTO) of free-living golden moles during both winter and summer at high altitude (1500 m). We used measurements of deuterium dilution to estimate body fat during these two periods. DEE, WTO and body mass did not differ significantly between seasons. However, RMR values were higher during the winter than the summer and, in the latter case were also lower than allometric predictions. Body fat was also higher during the winter. Calculations show that during the winter they may restrict activity to shorter, more intense periods. This, together with an increase in thermal insulation, might enable them to survive the cold. (c) 2005 Elsevier Inc. All rights reserved.