Improving the accuracy of heat balance integral methods applied to thermal problems with time dependent boundary conditions

In this paper the two main drawbacks of the heat balance integral methods are examined. Firstly we investigate the choice of approximating function. For a standard polynomial form it is shown that combining the Heat Balance and Refined Integral methods to determine the power of the highest order term will either lead to the same, or more often, greatly improved accuracy on standard methods. Secondly we examine thermal problems with a time-dependent boundary condition. In doing so we develop a logarithmic approximating function. This new function allows us to model moving peaks in the temperature profile, a feature that previous heat balance methods cannot capture. If the boundary temperature varies so that at some time t & 0 it equals the far-field temperature, then standard methods predict that the temperature is everywhere at this constant value. The new method predicts the correct behaviour. It is also shown that this function provides even more accurate results, when coupled with the new CIM, than the polynomial profile. Analysis primarily focuses on a specified constant boundary temperature and is then extended to constant flux, Newton cooling and time dependent boundary conditions.

Life Cycle and Reproductive Patterns of Triatoma rubrofasciata (De Geer, 1773) (Hemiptera: Reduviidae), under Laboratory Conditions

The life cycle and reproductive patterns of Triatoma rubrofasciata were studied along with laboratory conditions for the establishment of a prolific colony. The insects were divided into four groups: two of them were maintained at room temperature (20.5°C to 33°C and 85% ± 5% of relative humidity), the other two in a climatic chamber (CC) (temperature: 29°C, humidity: 80% ± 5%). The groups were fed weekly or fortnightly on Swiss mice. The females from the group kept in the CC and fed weekly had longer life span, as well as a higher number of eggs, fertile eggs and hatchings; the group kept in the CC and fed fortnightly had a shorter life span for the 1st, 2nd and 3rd instars and a lower mortality rate for all instars. It was concluded that a constant high temperature (CC at 29°C) is the most suitable condition for the maintenance of a colony of T. rubrofasciata regardless of the interval between repasts.

Resistance to Starvation of Triatoma rubrofasciata (De Geer, 1773) under Laboratory Conditions (Hemiptera: Reduviidae: Triatominae)

The present work aims at learning the period of resistance to starvation (molting/death) of Triatoma rubrofasciata in different stages of development and the respective loss of weight until death. Eggs of specimens from the greater area of the city of São Luis in the State of Maranhão, Brazil, yielded approximately 300 nymphs. These nymphs were placed in labelled Borrel glasses, in which they were weekly fed on rats (Rattus norvegicus), until reaching the stage to be observed. The experiments were conducted in a climatic chamber regulated at 29 ± 1° C, 70% relative humidity and 12 hr photoperiod. The resistance to starvation increased according to the stage of development, except for adult bugs, whose results were similar to the 3rd stage nymphs. In all these development stages there was an abrupt loss of weight in the first week, followed by a gradual loss until death. Comparing this work with those of other authors, it was observed that T. rubrofasciata is among the less resistant triatomine species.

Pale and dark reddish melanic tawny owls differentially regulate the level of blood circulating POMC prohormone in relation to environmental conditions.

Knowledge of the hormonal pathway controlling genotype-specific norms of reaction would shed light on the ecological factors to which each genotype is adapted. Environmentally mediated changes in the sign and magnitude of covariations between heritable melanin-based colouration and fitness components are frequent, revealing that extreme melanin-based phenotypes can display different physiological states depending on the environment. Yet, the hormonal mechanism underlying this phenomenon is poorly understood. One novel hypothesis proposes that these covariations stem from pleiotropic effects of the melanocortin system. Melanocortins are post-translationally modified bioactive peptides derived from the POMC prohormone that are involved in melanogenesis, anti-inflammation, energy homeostasis and stress responses. Thus, differential regulation of fitness components in relation to environmental factors by pale and dark melanic individuals may be due to colour-specific regulation of the POMC prohormone. Accordingly, we found that the degree of reddish melanic colouration was negatively correlated with blood circulating levels of the POMC prohormone in female tawny owls (Strix aluco) rearing a brood for which the size was experimentally reduced, but not when enlarged, and in females located in rich but not in poor territories. Our findings support the hypothesis that the widespread links between melanin-based colouration and fitness components may be mediated, at least in part, by the melanocortin system.

Survival, development and growth of larvae of the blue swimmer crab, Portunus pelagicus, cultured under different photoperiod conditions

The blue swimmer crab is a commercially important species of the tropical Indo-Pacific regions that shows substantial potential as a candidate species for aquaculture. Optimization of larval rearing conditions, including photoperiod, is therefore important to establish a method for the intensive hatchery culture of this species. Newly hatched larvae of Portunuspelagicus in first zoeal stage (ZI) were reared under five photoperiod regimes 0L: 24D, 6L: 18D, 12L: 12D, 18L: 6D, and 24L: 0D (5 replicates per treatment) till they metamorphosed to megalopae (ranged from 8.5 ± 0.3 days (18L: 6D) to 10.8 ± 1.8 days (0L: 24D) at 29 ± 1 °C). Daily, larvae of each treatment were fed an identical diet of mixed rotifer and Artemia nauplii, and the survival and molt to successive stages was monitored. Newly hatched ZI larvae of P. pelagicus could successfully develop to the megalopal stage under all tested photoperiod conditions, but we detected significant differences in survival among treatments (p & 0.05). The constant darkness treatment (0L: 24D) had the lowest (19.2 ± 7.2%, mean ± S.E.) cumulative survival from ZI to the megalopal stage, while the 18L: 6D treatment achieved the highest survival (51.2 ± 23.6%). Similarly, the photoperiod significantly affected zoeal development. Constant darkness led to the longest cumulative zoeal duration (10.8 ± 1.8 days), whereas the 18L: 6D treatment rendered the shortest larval development (8.5 ± 0.3 days). In addition, larvae reared under constant darkness resulted in the smallest megalopae (carapace length = 1.44 ± 0.09 mm) and the lowest dry weight (0.536 ± 0.188 mg). In conclusion, photoperiod significantly affected the survival, development, and growth of P. pelagicus zoeal larvae. Constant darkness led to the lowest larval survival and developmental rate, while a photoperiod regime of 18L: 6D appeared to be the most suitable condition for the rearing of zoeal larvae of P. pelagicus.

Development of Rhodnius prolixus (Hemiptera: Reduviidae) under Constant and Cyclic Conditions of Temperature and Humidity

Development of Rhodnius prolixus after eclosion until the adult stage was studied at constant temperatures (T), 15, 20, 25, 28, 35°C, and relative humidities (RH), 75, 86 and 97%, and fluctuating (16/8 hr) temperatures, T I/II, 15/28°C, 20/25°C, 25/28°C and 25/35°C, and relative humidities, RH I/II, 86/75% and 97/75%. Eclosion or molting were not observed at 15°C and 86 or 97% RH, respectively. At 35°C and 75% RH only few insects molted. By alternating T I/II, 15/28°C and 25/35°C, insects developed at high frequency. Cumulating the average lengths of the interphases within independent groups for each instar, R. prolixus reached the adult stage most rapidly (86.7 days) and at highest frequency per instar (mean: 91.8%) at 28°C and 75% RH. Under fluctuating T I/II, development was completed within 100 days or less at 25/28°C and 25/35°C with high rates of hatch and molting. Development was slowest at fluctuating TI/II, 15/28°C and 20/25°C (>185 days), and at constant 20°C (>300 days). Mortality was higher at constant 97% RH or fluctuating RH I, 97%, than at constant or fluctuating 86% RH. Refeeding was minimal at optimal conditions of T and RH for development. The most refeeding was observed at a constant 35°C.

Breath acetone to monitor life style interventions in field conditions: An exploratory study.

OBJECTIVE: To assess whether breath acetone concentration can be used to monitor the effects of a prolonged physical activity on whole body lipolysis and hepatic ketogenesis in field conditions. METHODS: Twenty-three non-diabetic, 11 type 1 diabetic, and 17 type 2 diabetic subjects provided breath and blood samples for this study. Samples were collected during the International Four Days Marches, in the Netherlands. For each participant, breath acetone concentration was measured using proton transfer reaction ion trap mass spectrometry, before and after a 30-50 km walk on four consecutive days. Blood non-esterified free fatty acid (NEFA), beta-hydroxybutyrate (BOHB), and glucose concentrations were measured after walking. RESULTS: Breath acetone concentration was significantly higher after than before walking, and was positively correlated with blood NEFA and BOHB concentrations. The effect of walking on breath acetone concentration was repeatedly observed on all four consecutive days. Breath acetone concentrations were higher in type 1 diabetic subjects and lower in type 2 diabetic subjects than in control subjects. CONCLUSIONS: Breath acetone can be used to monitor hepatic ketogenesis during walking under field conditions. It may, therefore, provide real-time information on fat burning, which may be of use for monitoring the lifestyle interventions.

Effects of environmental temperature on life tables of Rhodnius neivai Lent, 1953 (Hemiptera: Reduviidae) under experimental conditions

Changes in life tables of Rhodnius neivai due to variations of environmental temperature were studied, based on nine cohorts. Three cohorts were kept at 22°C, three at 27°C and three at 32°C. Cohorts were censused daily during nymphal instars and weekly in adults. Nine complete horizontal life tables were built. A high negative correlation between temperature and age at first laying was registered (r=-0,84). Age at maximum reproduction was significantly lower at 32°C. Average number of eggs/female/week and total eggs/female on its life time were significantly lower at 22°C. Total number of egg by cohort and total number of reproductive weeks were significantly higher at 27°C. At 32°C, generational time was significantly lower. At 27°C net reproductive rate and total reproductive value were significantly higher. At 22°C, intrinsic growth, finite growth and finite birth rates were significantly lower. At 22°C, death instantaneous rate was significantly higher.

Biology of Triatoma pallidipennis stal 1945 (Hemiptera: Reduviidae:Triatominae) under laboratory conditions

Aspects related to hatching, life time, mortality, feeding behaviour and fecundity for each stage of Triatoma pallidipennis life-cycle were evaluated. The hatching rate observed for 200 eggs was 60% and the average time of hatching was 18 days. Eighty nymphs (N) (40%) completed the cycle and the average time from NI to adult was 168.7±11.7days. The average span in days for each stage was 18.0 for NI, 18.5 for NII, 30.0 for NIII, 35.7 for NIV and 50.1 for NV. The number of bloodmeals at each nymphal stage varied from 1 to 5. The mortality rate was 9.17 for NI, 5.5 for NII, 6.8 for NIII 4.17 for NIV and 13.04 for NV nymphs. The average number of eggs laid per female in a 9-month period was 498.6. The survival rates of adults were 357±217.9 and 262.53±167.7 for males and females respectively.

Prevalence of chronic conditions – Stroke

IPH has estimated and forecast clinical diagnosis rates of stroke among adults for the years 2010, 2015 and 2020. In the Republic of Ireland, the data are based on the Survey of Lifestyle, Attitudes and Nutrition (SLÁN) 2007. The data describe the number of adults who report that they have experienced doctor-diagnosed stroke in the previous 12 months. Data are available by age and sex for each Local Health Office of the Health Service Executive (HSE) in the Republic of Ireland. In Northern Ireland, the data are based on the Health and Social Wellbeing Survey 2005/06. The data describe the number of adults who report that they have experienced doctor-diagnosed stroke at any time in the past. Data are available by age and sex for each Local Government District in Northern Ireland. Clinical diagnosis rates in the Republic of Ireland relate to the previous 12 months and are not directly comparable with clinical diagnosis rates in Northern Ireland which relate to anytime in the past. The IPH estimated prevalence per cents may be marginally different to estimated prevalence per cents taken directly from the reference study. There are two reasons for this: 1) The IPH prevalence estimates relate to 2010 while the reference studies relate to earlier years (Northern Ireland Health and Social Wellbeing Survey 2005/06, Survey of Lifestyle, Attitudes and Nutrition 2007, Understanding Society 2009). Although we assume that the risk of the condition in the risk groups do not change over time, the distribution of the number of people in the risk groups in the population changes over time (eg the population ages).  This new distribution of the risk groups in the population means that the risk of the condition is weighted differently to the reference study and this results in a different overall prevalence estimate. 2) The IPH prevalence estimates are based on a statistical model of the reference study. The model includes a number of explanatory variables to predict the risk of the condition. Therefore the model does not include records from the reference study that are missing data on these explanatory variables. A prevalence estimate for a condition taken directly from the reference study would include these records.