Begrip vir die lewenskonteks van mense as ’n vereiste vir pastorale begeleiding

Understanding the life context of people as a prerequisite for pastoral guidance In this article the importance of the context in which contemporary people live is discussed. Megatrends like internasionalism, the search for sense in life, secularism, paradigm changes associated with postmodernism and the African context are discussed. The South African context is also discussed regarding issues like transformation, the morality crisis, change in systems of faith, pressure on families, violence and crime, withdrawal from public life, joblessness, poverty, a new culture of human rights and a need for a work ethic. The value of understanding the life context of people is discussed in order to guide them to serve Christ

Influence of thermophysiology on thermal behavior: the essentials of categorization

Predicted energy use of dwellings often deviates from the actual energy use. Thermoregulatory behavior of the occupant might explain this difference. Such behavior is influenced by thermal sensation and thermal comfort. These subjective ratings in turn are linked to physiological parameters such as core and skin temperatures. However, it is unclear which physiological parameters best predict thermoregulatory behavior. The objective of this research was to study physiological parameters that potentially can be used to predict thermoregulatory behavior. Sixteen healthy females (18-30years) were exposed to two dynamic temperature protocols: a gradual increase (+4K/h, ranging from 24 degrees C to 32 degrees C) and a gradual decrease in ambient temperature (-4K/h, ranging from 24 degrees C to 16 degrees C). During the experiments physiological responses, thermal sensation, thermal preference and the intention of thermoregulatory behavior were measured. Thermal sensation is highly correlated with thermal preference (r=-0.933, P<0.001). The skin temperature of the wrist best predicts thermal sensation (R2=0.558, P<0.001) and therefore seems useful as a physiological parameter to predict the intention of thermoregulatory behavior. When the subjects are categorized based on their thermal sensation votes, more precise predictions of thermal sensation can be made. This categorization therefore can be of value for the determination of the actual energy use of occupant in dwellings

Mathematical modeling of thermal and circulatory effects during hemodialysis.

Intradialytic hypotension (IDH) is one of the most common complications of hemodialysis (HD) treatment. The initiating factor of IDH is a decrease in blood volume which is related to an imbalance between ultrafiltration (UF) and refilling rate. Impaired reactivity of resistance and capacitance vessels in reaction to hypovolemia plays possibly a major role in the occurrence of IDH. These vessels also fulfill an important function in body temperature regulation. UF induced cutaneous vasoconstriction would result in a reduced surface heat loss and an increase in core temperature. To release body heat, skin blood flow (SBF) is increased at a later stage of the HD treatment, whereby possibly IDH can occur. Aim of the study is to develop a mathematical model which can provide insight into the impact of thermoregulatory processes on the cardiovascular system during HD treatment. The mathematical procedure has been created by coupling a thermo-physiological (TP) model with a cardiovascular (CV) model to study regulation mechanisms in the human body during HD+UF. Model simulations for isothermal vs. thermoneutral HD+UF were compared to measurement data of patients on chronic intermittent HD (n=13). Core temperature during simulated HD+UF sessions increased within the range of measurement data (0.23ºC vs. 0.32±0.41ºC). The model showed a decline in mean arterial pressure (MAP) of -7% for thermoneutral HD+UF versus -4% for isothermal HD+UF after 200 minutes during which relative blood volume (RBV) changed by -13%. In conclusion, simulation results of the combined model show possibilities for predicting circulatory and thermal responses during HD+UF

The thermoneutral zone: implications for metabolic studies

A thermoneutral environment is important for many human physiological studies. The thermoneutral zone (TNZ) is defined as the range of ambient temperatures without regulatory changes in metabolic heat production or evaporative heat loss. Many factors influence the thermoneutral zone, such as body composition, clothing, energy expenditure, age and gender. These factors have the potential to introduce bias in study results and therefore need to be taken into consideration in many metabolic studies or studies on obesity, medical conditions, thermal comfort or vigilance. Given new developments on the TNZ combined with historical views the aim of this review is to 1) provide insight in how the human TNZ is affected by internal and external factors, 2) indicate how skin blood flow characteristics could be used as an objective criterion for determining whether someone is in the thermoneutral zone, 3) explain implications of the TNZ on metabolic studies and 4) indicate future directions to enhance understanding of the TNZ, especially for the elderly and obese

Frequent extreme cold exposure and brown fat and cold-induced thermogenesis: A study in a monozygotic twin

INTRODUCTION: Mild cold acclimation is known to increase brown adipose (BAT) activity and cold-induced thermogenesis (CIT) in humans. We here effect of a lifestyle with frequent exposure to extreme cold on BAT and Dutch man known as 'the Iceman', who has multiple world records in extreme cold challenges. Furthermore, his monozygotic twin brother who 'normal' sedentary lifestyle without extreme cold exposures was METHODS: The Iceman (subject A) and his brother (subject B) were studied mild cold (13 degrees C) and thermoneutral conditions (31 degrees C). Measurements included BAT activity and respiratory muscle activity by [18F]FDG-PET/CT imaging and energy expenditure through indirect addition, body temperatures, cardiovascular parameters, skin perfusion, thermal sensation and comfort were measured. Finally, we determined for uncoupling protein-1 and beta3-adrenergic receptor. RESULTS: comparable BAT activity (A: 1144 SUVtotal and B: 1325 SUVtotal), within previously observed in young adult men. They were genotyped with the for uncoupling protein-1 (G/G). CIT was relatively high (A: 40.1% and B: but unlike during our previous cold exposure tests in young adult men, subjects practiced a g-Tummo like breathing technique, which involves respiratory muscle activity. This was confirmed by high [18F]FDG-uptake respiratory muscle. CONCLUSION: No significant differences were found two subjects, indicating that a lifestyle with frequent exposures to does not seem to affect BAT activity and CIT. In both subjects, BAT was higher compared to earlier observations, whereas CIT was very high, that g-Tummo like breathing during cold exposure may cause additional production by vigorous isometric respiratory muscle contraction. The be interpreted with caution given the low subject number and the fact participants practised the g-Tummo like breathing technique

Measurement of model coefficients of skin sympathetic vasoconstriction

Many researchers have already attempted to model vasoconstriction responses, commonly using the mathematical representation proposed by Stolwijk (1971 NASA Contractor Report CR-1855 (Washington, DC: NASA)). Model makers based the parameter values in this formulation either on estimations or by attributing the difference between their passive models and measurement data fully to thermoregulation. These methods are very sensitive to errors. This study aims to present a reliable method for determining physiological values in the vasoconstriction formulation. An experimental protocol was developed that enabled us to derive the local proportional amplification coefficients of the toe, leg and arm and the transient vasoconstrictor tone. Ten subjects participated in a cooling experiment. During the experiment, core temperature, skin temperature, skin perfusion, forearm blood flow and heart rate variability were measured. The contributions to the normalized amplification coefficient for vasoconstriction of the toe, leg and arm were 84%, 11% and 5%, respectively. Comparison with relative values in the literature showed that the estimated values of Stolwijk and the values mentioned by Tanabe et al (2002 Energy Build. 34 637-46) were comparable with our measured values, but the values of Gordon (1974 The response of a human temperature regulatory system model in the cold PhD Thesis University of California, Santa Barbara) and Fiala et al (2001 Int. J. Biometeorol. 45 143159) differed significantly. With the help of regression analysis a relation was formulated between the error signal of the standardized core temperature and the vasoconstrictor tone. This relation was formulated in a general applicable way, which means that it can be used for situations where vasoconstriction thresholds are shifted, like under anesthesia or during motion sickness

Mathematical modeling of thermal and circulatory effects during hemodialysis.

Intradialytic hypotension (IDH) is one of the most common complications of hemodialysis (HD) treatment. The initiating factor of IDH is a decrease in blood volume, which is related to an imbalance between ultrafiltration (UF) and refilling rate. Impaired reactivity of resistance and capacitance vessels in reaction to hypovolemia plays possibly a major role in the occurrence of IDH. These vessels also fulfill an important function in body temperature regulation. UF-induced cutaneous vasoconstriction would result in a reduced surface heat loss and an increase in core temperature. To release body heat, skin blood flow is increased at a later stage of the HD treatment, whereby possibly IDH can occur. The aim of the study is to develop a mathematical model that can provide insight into the impact of thermoregulatory processes on the cardiovascular (CV) system during HD treatment. The mathematical procedure has been created by coupling a thermo-physiological model with a CV model to study regulation mechanisms in the human body during HD + UF. Model simulations for isothermal versus thermoneutral HD + UF were compared with measurement data of patients on chronic intermittent HD (n = 13). Core temperature during simulated HD + UF sessions increased within the range of measurement data (0.23 degrees C vs. 0.32 +/- 0.41 degrees C). The model showed a decline in mean arterial pressure of -7% for thermoneutral HD + UF versus -4% for isothermal HD + UF after 200 min during which relative blood volume changed by -13%. In conclusion, simulation results of the combined model show possibilities for predicting circulatory and thermal responses during HD + UF