Tolerance of larger body sizes by young adults living in Australia and Hawaii

Identifying the barriers to achieving an appropriate body size is important for health. This study investigated young adults' tolerance of excess weight in other adults. Participants were 172 students (65 male, 107 female) with a mean age of 22.24 years (SD = 1.61). Half the participants resided in Australia, and half in Hawaii. Students from both countries were found to be tolerant of body sizes larger than those recommended for good health. These results help inform our understanding of the factors that may influence weight gain, and have important implications for the worldwide obesity problem and related health issues.

Joint velocity redistribution for fault tolerant manipulators

If the end-effector of a robotic manipulator moves on a specified trajectory, then for the fault tolerant operation, it is required that the end-effector continues the trajectory with a minimum velocity jump when a fault occurs within a joint. This problem is addressed in the paper. A way to tolerate the fault is to find new joint velocities for the faulty manipulator in which results into the same end-effector velocity provided by the healthy manipulator. The aim of this study is to find a strategy which optimally redistributes the joint velocities for the remained healthy joints of the manipulators. The optimality is defined by the minimum end-effector velocity jump. A solution of the problem is presented and it is applied to a robotics manipulator. Then through a case study and a simulation study it is validated. The paper shows that if would be possible the joint velocity redistribution results into a zero velocity jump.

Reduced exercise tolerance in CHF may be related to factors other than impaired skeletal muscle oxidative capacity

Background : We sought to determine whether skeletal muscle oxidative capacity, fiber type proportions, and fiber size, capillary density or muscle mass might explain the impaired exercise tolerance in chronic heart failure (CHF). Previous studies are equivocal regarding the maladaptations that occur in the skeletal muscle of patients with CHF and their role in the observed exercise intolerance.

Methods and results : Total body O₂ uptake (VO_2peak) was determined in 14 CHF patients and 8 healthy sedentary similar-age controls. Muscle samples were analyzed for mitochondrial adenosine triphosphate (ATP) production rate (MAPR), oxidative and glycolytic enzyme activity, fiber size and type, and capillary density. CHF patients demonstrated a lower VO_2peak (15.1±1.1 versus 28.1±2.3 mL·kg⁻¹·min⁻¹, P<.001) and capillary to fiber ratio (1.09±0.05 versus 1.40±0.04; P<.001) when compared with controls. However, there was no difference in capillary density (capillaries per square millimeter) across any of the fiber types. Measurements of MAPR and oxidative enzyme activity suggested no difference in muscle oxidative capacity between the groups.

Conclusions : Neither reductions in muscle oxidative capacity nor capillary density appear to be the cause of exercise limitation in this cohort of patients. Therefore, we hypothesize that the low VO_2peak observed in CHF patients may be the result of fiber atrophy and possibly impaired activation of oxidative phosphorylation.

Navigation of four-wheel-steering mobile robots using robust fault-tolerant sliding mode control

This paper addresses the leader-follower tracking problem of a four-wheel-steering robot subjected to nonlinear uncertainties. Two control laws have been developed, based on the adaptive sliding mode method and the adaptive input-output feedback linearization method. The proposed control schemes have been tested by means of simulations.

Angiotensin converting enzyme inhibition lowers body weight and improves glucose tolerance in C57BL/6J mice maintained on a high fat diet

The renin–angiotensin system (RAS) is functional within adipose tissue and angiotensin II, the active component of RAS, has been implicated in adipose tissue hypertrophy and insulin resistance. In this study, captopril, an angiotensin converting enzyme (ACE) inhibitor that prevents angiotensin II formation, was used to study the development of diet-induced obesity and insulin resistance in obesity prone C57BL/6J mice. The mice were fed a high fat diet (w/w 21% fat) and allowed access to either water or water with captopril added (0.2 mg/ml). Body weight was recorded weekly and water and food intake daily. Glucose tolerance was determined after 11–12 weeks. On completion of the study (after 16 weeks of treatment), the mice were killed and kidney, liver, epididymal fat and extensor digitorum longus muscle (EDL) were weighed. Blood samples were collected and plasma analysed for metabolites and hormones. Captopril treatment decreased body weight in the first 2 weeks of treatment. Food intake of captopril-treated mice was similar to control mice prior to weight loss and was decreased after weight loss. Glucose tolerance was improved in captopril-treated mice. Captopril-treated mice had less epididymal fat than control mice. Relative to body weight, captopril-treated mice had increased EDL weight. Relative to control mice, mice administered captopril had a higher plasma concentration of adiponectin and lower concentrations of leptin and non-esterified fatty acids (NEFA). The results indicate that captopril both induced weight loss and improved insulin sensitivity. Thus, captopril may eventually be used for the treatment of obesity and Type 2 diabetes.

Optimal fault-tolerant robotic manipulators

This thesis addresses “Optimal Fault-Tolerant Robotic Manipulators” for locked-joint failures and consists of three components. It begins by investigating the regions of workspace where the manipulator can operate with high reliability. It then continues with an efficient deployment of kinematic redundancies for fault-tolerant operation. Finally, it presents a novel method for design of optimal fault-tolerant manipulators.

Heat tolerance, behavioural temperature selection and temperature-dependent respiration in larval Octopus huttoni

This study reports temperature effects on paralarvae from a benthic octopus species, Octopus huttoni, found throughout New Zealand and temperate Australia. We quantified the thermal tolerance, thermal preference and temperature-dependent respiration rates in 1-5 days old paralarvae. Thermal stress (1°C increase h^-1) and thermal selection (~10-24°C vertical gradient) experiments were conducted with paralarvae reared for 4 days at 16°C. In addition, measurement of oxygen consumption at 10, 15, 20 and 25°C was made for paralarvae aged 1, 4 and 5 days using microrespirometry. Onset of spasms, rigour (CT_max) and mortality (upper lethal limit) occurred for 50% of experimental animals at, respectively, 26.0±0.2°C, 27.8±0.2°C and 31.4±0.1°C. The upper, 23.1±0.2°C, and lower, 15.0±1.7°C, temperatures actively avoided by paralarvae correspond with the temperature range over which normal behaviours were observed in the thermal stress experiments. Over the temperature range of 10°C-25°C, respiration rates, standardized for an individual larva, increased with age, from 54.0 to 165.2nmol larvae^-1h^-1 in one-day old larvae to 40.1-99.4nmol h^-1 at five days. Older larvae showed a lesser response to increased temperature: the effect of increasing temperature from 20 to 25°C (Q₁₀) on 5 days old larvae (Q₁₀=1.35) was lower when compared with the 1 day old larvae (Q₁₀=1.68). The lower Q₁₀ in older larvae may reflect age-related changes in metabolic processes or a greater scope of older larvae to respond to thermal stress such as by reducing activity. Collectively, our data indicate that temperatures >25°C may be a critical temperature. Further studies on the population-level variation in thermal tolerance in this species are warranted to predict how continued increases in ocean temperature will limit O. huttoni at early larval stages across the range of this species.

A hybrid intelligent system and its application to fault detection and diagnosis

This paper proposes a hybrid system that integrates the SOM (Self Organizing Map) neural network, the kMER (kernel-based Maximum Entropy learning Rule) algorithm and the Probabilistic Neural Network (PNN) for data visualization and classification. The rationales of this hybrid SOM-kMER-PNN model are explained, and the applicability of the proposed model is demonstrated using two benchmark data sets and a real-world application to fault detection and diagnosis. The outcomes show that the hybrid system is able to achieve comparable classification rates when compared to those from a number of existing classifiers and, at the same time, to produce meaningful visualization of the data sets.