Effect of ambient temperature on emergency department visits in Shanghai, China: a time series study.

PubMed

Zhang, Yue; Yan, Chenyang; Kan, Haidong; Cao, Junshan; Peng, Li; Xu, Jianming; Wang, Weibing

2014-11-25

Many studies have examined the association between ambient temperature and mortality. However, less evidence is available on the temperature effects on gender- and age-specific emergency department visits, especially in developing countries. In this study, we examined the short-term effects of daily ambient temperature on emergency department visits (ED visits) in Shanghai. Daily ED visits and daily ambient temperatures between January 2006 and December 2011 were analyzed. After controlling for secular and seasonal trends, weather, air pollution and other confounding factors, a Poisson generalized additive model (GAM) was used to examine the associations between ambient temperature and gender- and age-specific ED visits. A moving average lag model was used to evaluate the lag effects of temperature on ED visits. Low temperature was associated with an overall 2.76% (95% confidence interval (CI): 1.73 to 3.80) increase in ED visits per 1°C decrease in temperature at Lag1 day, 2.03% (95% CI: 1.04 to 3.03) and 2.45% (95% CI: 1.40 to 3.52) for males and females. High temperature resulted in an overall 1.78% (95% CI: 1.05 to 2.51) increase in ED visits per 1°C increase in temperature on the same day, 1.81% (95% CI: 1.08 to 2.54) among males and 1.75% (95% CI: 1.03 to 2.49) among females. The cold effect appeared to be more acute among younger people aged <45 years, whereas the effects were consistent on individuals aged ≥65 years. In contrast, the effects of high temperature were relatively consistent over all age groups. These findings suggest a significant association between ambient temperature and ED visits in Shanghai. Both cold and hot temperatures increased the relative risk of ED visits. This knowledge has the potential to advance prevention efforts targeting weather-sensitive conditions.

Plant molecular responses to the elevated ambient temperatures expected under global climate change.

PubMed

Fei, Qionghui; Li, Jingjing; Luo, Yunhe; Ma, Kun; Niu, Bingtao; Mu, Changjun; Gao, Huanhuan; Li, Xiaofeng

2018-01-02

Environmental temperatures affect plant distribution, growth, and development. The Intergovernmental Panel on Climate Change (IPCC) predicts that global temperatures will rise by at least 1.5°C by the end of this century. Global temperature changes have already had a discernable impact on agriculture, phenology, and ecosystems. At the molecular level, extensive literature exists on the mechanism controlling plant responses to high temperature stress. However, few studies have focused on the molecular mechanisms behind plant responses to mild increases in ambient temperature. Previous research has found that moderately higher ambient temperatures can induce hypocotyl elongation and early flowering. Recent evidence demonstrates roles for the phytohormones auxin and ethylene in adaptive growth of plant roots to slightly higher ambient temperatures.

Compliant Foil Journal Bearing Performance at Alternate Pressures and Temperatures

NASA Technical Reports Server (NTRS)

Bruckner, Robert J.; Puleo, Bernadette J.

2008-01-01

An experimental test program has been conducted to determine the highly loaded performance of current generation gas foil bearings at alternate pressures and temperatures. Typically foil bearing performance has been reported at temperatures relevant to turbomachinery applications but only at an ambient pressure of one atmosphere. This dearth of data at alternate pressures has motivated the current test program. Two facilities were used in the test program, the ambient pressure rig and the high pressure rig. The test program utilized a 35 mm diameter by 27 mm long foil journal bearing having an uncoated Inconel X-750 top foil running against a shaft with a PS304 coated journal. Load capacity tests were conducted at 3, 6, 9, 12, 15, 18, and 21 krpm at temperatures from 25 to 500 C and at pressures from 0.1 to 2.5 atmospheres. Results show an increase in load capacity with increased ambient pressure and a reduction in load capacity with increased ambient temperature. Below one-half atmosphere of ambient pressure a dramatic loss of load capacity is experienced. Additional lightly loaded foil bearing performance in nitrogen at 25 C and up to 48 atmospheres of ambient pressure has also been reported. In the lightly loaded region of operation the power loss increases for increasing pressure at a fixed load. Knowledge of foil bearing performance at operating conditions found within potential machine applications will reduce program development risk of future foil bearing supported turbomachines.

Temperature effects on metabolic rate of juvenile Pacific bluefin tuna Thunnus orientalis.

PubMed

Blank, Jason M; Morrissette, Jeffery M; Farwell, Charles J; Price, Matthew; Schallert, Robert J; Block, Barbara A

2007-12-01

Pacific bluefin tuna inhabit a wide range of thermal environments across the Pacific ocean. To examine how metabolism varies across this thermal range, we studied the effect of ambient water temperature on metabolic rate of juvenile Pacific bluefin tuna, Thunnus thynnus, swimming in a swim tunnel. Rate of oxygen consumption (MO2) was measured at ambient temperatures of 8-25 degrees C and swimming speeds of 0.75-1.75 body lengths (BL) s(-1). Pacific bluefin swimming at 1 BL s(-1) per second exhibited a U-shaped curve of metabolic rate vs ambient temperature, with a thermal minimum zone between 15 degrees C to 20 degrees C. Minimum MO2 of 175+/-29 mg kg(-1) h(-1) was recorded at 15 degrees C, while both cold and warm temperatures resulted in increased metabolic rates of 331+/-62 mg kg(-1) h(-1) at 8 degrees C and 256+/-19 mg kg(-1) h(-1) at 25 degrees C. Tailbeat frequencies were negatively correlated with ambient temperature. Additional experiments indicated that the increase in MO2 at low temperature occurred only at low swimming speeds. Ambient water temperature data from electronic tags implanted in wild fish indicate that Pacific bluefin of similar size to the experimental fish used in the swim tunnel spend most of their time in ambient temperatures in the metabolic thermal minimum zone.

Alterations in MAST suit pressure with changes in ambient temperature.

PubMed

Sanders, A B; Meislin, H W; Daub, E

1983-01-01

A study was undertaken to test the hypothesis that change in ambient air temperature has an effect on MAST suit pressure according to the ideal gas law. Two different MAST suits were tested on Resusci-Annie dummies. The MAST suits were applied in a cold room at 4.4 degrees C and warmed to 44 degrees C. Positive linear correlations were found in nine trials, but the two suits differed in their rate of increase in pressure. Three trials using humans were conducted showing increased pressure with temperature but at a lesser rate than with dummies. A correlation of 0.5 to 1.0 mm Hg increase in MAST suit pressure for each 1.0 degrees C increase in ambient temperature was found. Implications are discussed for the use of the MAST suit in environmental conditions where the temperature changes.

Influence of the Environment on Body Temperature of Racing Greyhounds.

PubMed

McNicholl, Jane; Howarth, Gordon S; Hazel, Susan J

2016-01-01

Heat strain is a potential risk factor for racing greyhounds in hot climates. However, there have been limited studies into the incidence of heat strain (when excess heat causes physiological or pathological effects) in racing greyhounds. The aim of this study was to determine if heat strain occurs in racing greyhounds, and, if so, whether environmental factors (e.g., ambient temperature and relative humidity) or dog-related factors (e.g., sex, bodyweight, color) are associated with the risk of heat strain. A total of 229 greyhounds were included in over 46 race meetings and seven different race venues in South Australia, Australia. Rectal temperatures of dogs were measured pre- and postrace and urine samples collected for analysis of myoglobinuria. Ambient temperature at race times ranged between 11.0 and 40.8°C and relative humidity ranged from 17 to 92%. There was a mean increase in greyhound rectal temperature of 2.1°C (range 1.1-3.1°C). A small but significant association was present between ambient temperature and increase in rectal temperature (r (2) = 0.033, P = 0.007). The mean ambient temperature at race time, of dogs with postrace rectal temperature of or exceeding 41.5°C, was significantly greater than at race time of dogs with a postrace rectal temperature ≤41.5°C (31.2 vs. 27.3°C, respectively, P = 0.004). When the ambient temperature reached 38(o)C, over one-third (39%) of dogs had a rectal temperature >41.5°C. Over half of postrace urine samples were positive by Dipstick reading for hemoglobin/myoglobin, and of 77 urine samples positive for Dipstick readings, 95% were positive for myoglobin. However, urinary myoglobin levels were not associated with ambient temperature or postrace rectal temperatures. The mean increase in rectal temperature was greater in dark (black, blue, brindle) than light (fawn and white) colored greyhounds. The results suggest heat strain occurs in racing greyhounds, evidenced by postrace rectal temperatures over 41.5°C and postrace myoglobinuria. Risk of heat strain may be increased in higher ambient temperatures and in darker colored greyhounds. Further research into the incidence of heat strain in racing greyhounds, and longer term physiological responses to heat strain, are warranted.

Influence of the Environment on Body Temperature of Racing Greyhounds

PubMed Central

McNicholl, Jane; Howarth, Gordon S.; Hazel, Susan J.

2016-01-01

Heat strain is a potential risk factor for racing greyhounds in hot climates. However, there have been limited studies into the incidence of heat strain (when excess heat causes physiological or pathological effects) in racing greyhounds. The aim of this study was to determine if heat strain occurs in racing greyhounds, and, if so, whether environmental factors (e.g., ambient temperature and relative humidity) or dog-related factors (e.g., sex, bodyweight, color) are associated with the risk of heat strain. A total of 229 greyhounds were included in over 46 race meetings and seven different race venues in South Australia, Australia. Rectal temperatures of dogs were measured pre- and postrace and urine samples collected for analysis of myoglobinuria. Ambient temperature at race times ranged between 11.0 and 40.8°C and relative humidity ranged from 17 to 92%. There was a mean increase in greyhound rectal temperature of 2.1°C (range 1.1–3.1°C). A small but significant association was present between ambient temperature and increase in rectal temperature (r2 = 0.033, P = 0.007). The mean ambient temperature at race time, of dogs with postrace rectal temperature of or exceeding 41.5°C, was significantly greater than at race time of dogs with a postrace rectal temperature ≤41.5°C (31.2 vs. 27.3°C, respectively, P = 0.004). When the ambient temperature reached 38oC, over one-third (39%) of dogs had a rectal temperature >41.5°C. Over half of postrace urine samples were positive by Dipstick reading for hemoglobin/myoglobin, and of 77 urine samples positive for Dipstick readings, 95% were positive for myoglobin. However, urinary myoglobin levels were not associated with ambient temperature or postrace rectal temperatures. The mean increase in rectal temperature was greater in dark (black, blue, brindle) than light (fawn and white) colored greyhounds. The results suggest heat strain occurs in racing greyhounds, evidenced by postrace rectal temperatures over 41.5°C and postrace myoglobinuria. Risk of heat strain may be increased in higher ambient temperatures and in darker colored greyhounds. Further research into the incidence of heat strain in racing greyhounds, and longer term physiological responses to heat strain, are warranted. PMID:27446941

Does maternal exposure during pregnancy to higher ambient temperature increase the risk of hypospadias?

PubMed

Kilinc, Muhammet Fatih; Cakmak, Sedat; Demir, Demirhan Orsan; Doluoglu, Omer Gokhan; Yildiz, Yildiray; Horasanli, Kaya; Dalkilic, Ayhan

2016-12-01

The association between ambient temperature that the mother is exposed to during pregnancy and hypospadias has not been investigated by the studies, although the recent studies showed the correlation between some congenital malformations (congenital heart disease, neural tube defect, etc.) and ambient temperature. The aim was to investigate the relation between hypospadias and the ambient temperatures that the mother is exposed to during her pregnancy. The data of patients with hypospadias that had their gestational periods in Ankara and Istanbul regions, and had other urological treatments (circumcision, urinary tract infection, pyeloplasty, nephrolithotomy, etc.) between January 2000 and November 2015 were analyzed retrospectively. The ambient temperature at 8-14 weeks of gestation was investigated for each patient by reviewing the data of the General Directorate of Meteorology, since this period was risky for development of hypospadias. The data including ambient temperature that the pregnant mother was exposed to, maternal age, parity, economical status, gestational age at birth, and birth weight were compared between two groups. The retrospective nature of the study may be a potential source for selection bias. The data of 1,709 children that had hypospadias repair and 4,946 children that had other urological treatments between 2000 and 2015 were retrospectively analyzed. There were no differences between the groups for maternal age, parity, economical status, gestational age at birth, and birth weight (Table). Analysis of exposed maximum and average ambient temperatures at 8-14 weeks of gestation revealed that July and August, hot periods in summer time, were more prevalent in the hypospadias group (p = 0.01). The average and maximum monthly ambient temperatures during summer increased the risk for hypospadias (OR, 1.32; 95% CI, 1.08-1.52; and OR, 1.22; 95% CI, 0.99-1.54, respectively. In this paper, we evaluated the relation between hypospadias and the ambient temperatures that the mother is exposed during her pregnancy. The results of this study indicated that the high ambient temperatures the mother and fetus are exposed to at 8-14 weeks of gestation increased the risk of hypospadias in the offspring. Copyright © 2016 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Scots pine responses to elevated temperature and carbon dioxide concentration: growth and wood properties.

PubMed

Kilpeläinen, Antti; Peltola, Heli; Ryyppö, Aija; Kellomäki, Seppo

2005-01-01

Growth and wood properties of 20-year-old Scots pine (Pinus sylvestris L.) trees were studied for 6 years in 16 closed chambers providing a factorial combination of two temperature regimes (ambient and elevated) and two carbon dioxide concentrations ([CO2]) (ambient and twice ambient). The elevation of temperature corresponded to the predicted effect at the site of a doubling in atmospheric [CO2]. Annual height and radial growth and wood properties were analyzed during 1997-2002. Physical wood properties analyzed included early- and latewood widths and their proportions, intra-ring wood densities, early- and latewood density and mean fiber length. Chemical wood properties analyzed included concentrations of acetone-soluble extractives, lignin, cellulose and hemicellulose. There were no significant treatment effects on height growth during the 6-year study. Elevated [CO2] increased ring width by 66 and 47% at ambient and elevated temperatures, respectively. At ambient [CO2], elevated temperature increased ring width by 19%. Increased ring width in response to elevated [CO2] resulted from increases in both early- and latewood width; however, there was no effect of the treatments on early- and latewood proportions. Mean wood density, earlywood density and fiber length increased in response to elevated temperature. The chemical composition of wood was affected by elevated [CO2], which reduced the cellulose concentration, and by elevated temperature, which reduced the concentration of acetone-soluble extractives. Thus, over the 6-year period, radial growth was significantly increased by elevated [CO2], and some wood properties were significantly affected by elevated temperature or elevated [CO2], or both, indicating that climate change may affect the material properties of wood.

Influence of preservation methods on the quality of colostrum sourced from New Zealand dairy farms.

PubMed

Denholm, K S; Hunnam, J C; Cuttance, E L; McDougall, S

2017-09-01

To assess the effect of two temperatures (ambient temperature and 4°C), three preservation methods (no preservative, yoghurt and potassium sorbate), and two periods of storage (3 and 7 days) on Brix and total bacterial and coliform counts of colostrum collected from New Zealand dairy farms. One litre of colostrum destined to be fed to newborn calves was collected from 55 New Zealand dairy farms in the spring of 2015. Six aliquots of 150 mL were obtained from each colostrum sample, with two aliquots left untreated, two treated with potassium sorbate and two with yoghurt, and one of each pair of aliquots stored at ambient temperature and the other at 4°C. All samples were tested for Brix, total bacterial counts and coliform counts before treatment (Day 0), and after 3 and 7 days of storage. The effect of preservation method and storage temperature on the change in Brix, bacterial and coliform counts after 3 or 7 days of storage was analysed using multivariable random effects models. For all outcome variables there was a temperature by preservation interaction. For aliquots preserved with potassium sorbate, changes in Brix and bacterial counts did not differ between aliquots stored at ambient temperature or 4°C, but for aliquots preserved with yoghurt or no preservative the decrease in Brix and increase in bacterial counts was greater for aliquots stored at ambient temperature than 4°C (p<0.001). For aliquots preserved with potassium sorbate, coliform counts decreased at both temperatures, but for aliquots preserved with yoghurt or no preservative coliform counts increased for aliquots stored at 4°C, but generally decreased at ambient temperatures (p<0.001). There was also an interaction between duration of storage and temperature for bacterial counts (p<0.001). The difference in the increase in bacterial counts between aliquots stored at 4°C and ambient temperature after 3 days was greater than between aliquots stored at 4°C and ambient temperature after 7 days. Use of potassium sorbate to preserve colostrum for 3 or 7 days resulted in little or no reduction in Brix and a lower increase in total bacterial counts than colostrum stored without preservative or with yoghurt added. Colostrum quality was not affected by storage temperature for samples preserved with potassium sorbate, but storage at 4°C resulted in better quality colostrum than storage at ambient temperatures for colostrum with no preservative or yoghurt added.

Genetic variation for farrowing rate in pigs in response to change in photoperiod and ambient temperature.

PubMed

Sevillano, C A; Mulder, H A; Rashidi, H; Mathur, P K; Knol, E F

2016-08-01

Seasonal infertility is often observed as anestrus and a lower conception rate resulting in a reduced farrowing rate (FR) during late summer and early autumn. This is often regarded as an effect of heat stress; however, we observed a reduction in the FR of sows even after correcting for ambient temperature in our data. Therefore, we added change in photoperiod in the analysis of FR considering its effect on sow fertility. Change in photoperiod was modeled using the cosine of the day of first insemination within a year. On an average, the FR decreased by 2% during early autumn with decreasing daily photoperiod compared with early summer with almost no change in daily photoperiod. It declined 0.2% per degree Celsius of ambient temperature above 19.2°C. This result is a step forward in disentangling the 2 environmental components responsible for seasonal infertility. Our next aim was to estimate the magnitude of genetic variation in FR in response to change in photoperiod and ambient temperature to explore opportunities for selecting pigs to have a constant FR throughout the year. We used reaction norm models to estimate additive genetic variation in response to change in photoperiod and ambient temperature. The results revealed a larger genetic variation at stressful environments when daily photoperiod decreased and ambient temperatures increased above 19.2°C compared with neutral environments. Genetic correlations between stressful environments and nonstressful environments ranged from 0.90 (±0.03) to 0.46 (±0.13) depending on the severity of the stress, indicating changes in expression of FR depending on the environment. The genetic correlation between responses of pigs to changes in photoperiod and to those in ambient temperature were positive, indicating that pigs tolerant to decreasing daily photoperiod are also tolerant to high ambient temperatures. Therefore, selection for tolerance to decreasing daily photoperiod should also increase tolerance to high ambient temperatures or vice versa.

Suicide and Ambient Temperature in East Asian Countries: A Time-Stratified Case-Crossover Analysis

PubMed Central

Kim, Yoonhee; Honda, Yasushi; Guo, Yue Leon; Chen, Bing-Yu; Woo, Jong-Min; Ebi, Kristie L.

2015-01-01

Background A limited number of studies suggest that ambient temperature contributes to suicide; these studies typically focus on a single nation and use temporally and spatially aggregated data. Objective We evaluated the association between ambient temperature and suicide in multiple cities in three East Asian countries. Methods A time-stratified case-crossover method was used to explore the relationship between temperature and suicide, adjusting for potential time-varying confounders and time-invariant individual characteristics. Sex- and age-specific associations of temperature with suicide were estimated, as were interactions between temperature and these variables. A random-effects meta-analysis was used to estimate country-specific pooled associations of temperature with suicide. Results An increase in temperature corresponding to half of the city-specific standard deviation was positively associated with suicide in most cities, although average suicide rates varied substantially. Pooled country-level effect estimates were 7.8% (95% CI: 5.0, 10.8%) for a 2.3°C increase in ambient temperature in Taiwan, 6.8% (95% CI: 5.4, 8.2%) for a 4.7°C increase in Korea, and 4.5% (95% CI: 3.3, 5.7%) for a 4.2°C increase in Japan. The association between temperature and suicide was significant even after adjusting for sunshine duration; the association between sunshine and suicide was not significant. The associations were greater among men than women in 12 of the 15 cities although not significantly so. There was little evidence of a consistent pattern of associations with age. In general, associations were strongest with temperature on the same day or the previous day, with little evidence of associations with temperature over longer lags (up to 5 days). Conclusions We estimated consistent positive associations between suicide and elevated ambient temperature in three East Asian countries, regardless of country, sex, and age. Citation Kim Y, Kim H, Honda Y, Guo YL, Chen BY, Woo JM, Ebi KL. 2016. Suicide and ambient temperature in East Asian countries: a time-stratified case-crossover analysis. Environ Health Perspect 124:75–80; http://dx.doi.org/10.1289/ehp.1409392 PMID:26069051

The impact of elevated CO2 and temperature on grain quality of rice grown under open-air field conditions.

PubMed

Jing, Liquan; Wang, Juan; Shen, Shibo; Wang, Yunxia; Zhu, Jianguo; Wang, Yulong; Yang, Lianxin

2016-08-01

Rising atmospheric CO2 is accompanied by global warming. However, interactive effects of elevated CO2 and temperature have not been well studied on grain quality of rice. A japonica cultivar was grown in the field using a free-air CO2 enrichment facility in combination with a canopy air temperature increase system in 2014. The gas fumigation (200 µmol mol(-1) above ambient CO2 ) and temperature increase (1 °C above ambient air temperature) were performed from tillering until maturity. Compared with the control (ambient CO2 and air temperature), elevated CO2 increased grain length and width as well as grain chalkiness but decreased protein concentrations. In contrast, the increase in canopy air temperature had less effect on these parameters except for grain chalkiness. The starch pasting properties of rice flour and taste analysis of cooked rice indicated that the palatability of rice was improved by CO2 and/or temperature elevation, with the combination of the two treatments showing the most significant changes compared with ambient rice. It is concluded that projected CO2 in 2050 may have larger effects on rice grain quality than the projected temperature increase. Although deterioration in milling suitability, grain appearance and nutritional quality can be expected, the taste of cooked rice might be better in the future environment. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Effects of ambient temperature on mechanomyography of resting quadriceps muscle.

PubMed

McKay, William P; Vargo, Michael; Chilibeck, Philip D; Daku, Brian L

2013-03-01

It has been speculated that resting muscle mechanical activity, also known as minor tremor, microvibration, and thermoregulatory tonus, has evolved to maintain core temperature in homeotherms, and may play a role in nonshivering thermogenesis. This experiment was done to determine whether resting muscle mechanical activity increases with decreasing ambient temperature. We cooled 20 healthy, human, resting, supine subjects from an ambient temperature of 40° to 12 °C over 65 min. Core temperature, midquadriceps mechanomyography, surface electromyography, and oxygen consumption (VO2) were recorded. Resting muscle mechanical and electrical activity in the absence of shivering increased significantly at temperatures below 21.5 °C. Women defended core temperature more effectively than men, and showed increased resting muscle activity earlier than men. Metabolism measured by VO2 correlated with resting muscle mechanical activity (R = 0.65; p = 0.01). Resting muscle mechanical activity may have evolved, in part, to maintain core temperature in the face of mild cooling.

Respiratory alkalosis and primary hypocapnia in Labrador Retrievers participating in field trials in high-ambient-temperature conditions.

PubMed

Steiss, Janet E; Wright, James C

2008-10-01

To determine whether Labrador Retrievers participating in field trials develop respiratory alkalosis and hypocapnia primarily in conditions of high ambient temperatures. 16 Labrador Retrievers. At each of 5 field trials, 5 to 10 dogs were monitored during a test (retrieval of birds over a variable distance on land [1,076 to 2,200 m]; 36 assessments); ambient temperatures ranged from 2.2 degrees to 29.4 degrees C. For each dog, rectal temperature was measured and a venous blood sample was collected in a heparinized syringe within 5 minutes of test completion. Blood samples were analyzed on site for Hct; pH; sodium, potassium, ionized calcium, glucose, lactate, bicarbonate, and total CO2 concentrations; and values of PvO2 and PvCO2. Scatterplots of each variable versus ambient temperature were reviewed. Regression analysis was used to evaluate the effect of ambient temperature (< or = 21 degrees C and > 21 degrees C) on each variable. Compared with findings at ambient temperatures < or = 21 degrees C, venous blood pH was increased (mean, 7.521 vs 7.349) and PvCO2 was decreased (mean, 17.8 vs 29.3 mm Hg) at temperatures > 21 degrees C; rectal temperature did not differ. Two dogs developed signs of heat stress in 1 test at an ambient temperature of 29 degrees C; their rectal temperatures were higher and PvCO2 values were lower than findings in other dogs. When running distances frequently encountered at field trials, healthy Labrador Retrievers developed hyperthermia regardless of ambient temperature. Dogs developed respiratory alkalosis and hypocapnia at ambient temperatures > 21 degrees C.

Elevated temperature and CO(2) concentration effects on xylem anatomy of Scots pine.

PubMed

Kilpeläinen, Antti; Gerendiain, Ane Zubizarreta; Luostarinen, Katri; Peltola, Heli; Kellomäki, Seppo

2007-09-01

We studied the effects of elevated temperature and carbon dioxide concentration ([CO(2)]) alone and together on wood anatomy of 20-year-old Scots pine (Pinus sylvestris L.) trees. The study was conducted in 16 closed chambers, providing a factorial combination of two temperature regimes and two CO(2) concentrations (ambient and elevated), with four trees in each treatment. The climate scenario included a doubling of [CO(2)] and a corresponding increase of 2-6 degrees C in temperature at the site depending on the season. Anatomical characteristics analyzed were annual earlywood, latewood and ring widths, intra-ring wood densities (earlywood, latewood and mean wood density), tracheid width, length, wall thickness, lumen diameter, wall thickness:lumen diameter ratio and mass per unit length (coarseness), and numbers of rays, resin canals and tracheids per xylem cross-sectional area. Elevated [CO(2)] increased ring width in four of six treatment years; earlywood width increased in the first two years and latewood width in the third year. Tracheid walls in both the earlywood and latewood tended to become thicker over the 6-year treatment period when temperature or [CO(2)] was elevated alone, whereas in the combined treatment they tended to become thinner relative to the tracheids of trees grown under ambient conditions. Latewood tracheid lumen diameters were larger in all the treatments relative to ambient conditions over the 6-year period, whereas lumen diameters in earlywood increased only in response to elevated [CO(2)] and were 3-6% smaller in the treatments with elevated temperature than in ambient conditions. Tracheid width, length and coarseness were greater in trees grown in elevated than in ambient temperature. The number of resin canals per mm(2) decreased in the elevated [CO(2)] treatment and increased in the elevated temperature treatments relative to ambient conditions. The treatments decreased the number of rays and tracheids per mm(2) of cross-sectional area, the greatest decrease occurring in the elevated [CO(2)] treatment. It seemed that xylem anatomy was affected more by elevated temperature than by elevated [CO(2)] and that the effects of temperature were confined to the earlywood.

Effects of different acute high ambient temperatures on function of hepatic mitochondrial respiration, antioxidative enzymes, and oxidative injury in broiler chickens.

PubMed

Tan, G-Y; Yang, L; Fu, Y-Q; Feng, J-H; Zhang, M-H

2010-01-01

This study investigated the effects of different acute high ambient temperatures on dysfunction of hepatic mitochondrial respiration, the antioxidative enzyme system, and oxidative injury in broiler chickens. One hundred twenty-eight 6-wk-old broiler chickens were assigned randomly to 4 groups and subsequently exposed to 25 (control), 32, 35, and 38 degrees C (RH, 70 +/- 5%) for 3 h, respectively. The rectal temperatures, activity of antioxidative enzymes (superoxide dismutase, catalase, and glutathione peroxidase), content of malondialdehyde and protein carbonyl, and the activity of mitochondrial respiratory enzymes were determined. The results showed that exposure to high ambient temperature induced a significant elevation of rectal temperature, antioxidative enzyme activity, and formation of malondialdehyde and protein carbonyl, as well as dysfunction of the mitochondrial respiratory chain in comparison with control (P < 0.05). Almost all of the indicators changed in a temperature-dependent manner with the gradual increase of ambient temperature from 32 to 38 degrees C; differences in each parameter (except catalase) among the groups exposed to different high ambient temperatures were also statistically significant (P < 0.05). The results of the present study suggest that, in the broiler chicken model used here, acute exposure to high temperatures may depress the activity of the mitochondrial respiratory chain. This inactivation results subsequently in overproduction of reactive oxygen species, which ultimately results in oxidative injury. However, this hypothesis needs to be evaluated more rigorously in future studies. It has also been shown that, with the gradual increase in temperature, the oxidative injury induced by heat stress in broiler chickens becomes increasingly severe, and this stress response presents in a temperature-dependent manner in the temperature range of 32 to 38 degrees C.

The effects of reduced ambient temperatures on the warm-up fuel consumption behavior of gasoline fueled automobiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pucher, G.R.; Gardiner, D.P.; Mallory, R.W.

Warm-up fuel consumption behavior as affected by ambient temperature was evaluated for five OEM gasoline fueled automobiles. Multiple EPA FTP 75 tests were performed with each vehicle at ambient test cell soak temperatures of 25 C and {minus}7 C. Fuel consumption measured during the warm-up (Bag 1, Cold Transient) test segments at these two temperature conditions was compared to the fully warmed Hot Transient (Bag 3) fuel consumption from the 25 C ambient temperature tests (the Bag 1 and Bag 3 segments involve identical speed curves). Fuel consumption increases over the 25 C Bag 3 tests for the two warm-upmore » test conditions were differentiated as those caused by increased drivetrain losses and those caused by intake charge enrichment. Results show wide variations in warm-up behavior among the five vehicles with respect to the relative increases in fuel consumption, and the proportion of the fuel consumption increases attributable to drivetrain losses and enrichment. It was discovered that the most sophisticated vehicle systems do not necessarily facilitate the least degradation in fuel consumption with respect to baseline conditions for the group of vehicles tested.« less

An epidemiological assessment of the effect of ambient temperature on the incidence of preterm births: Identifying windows of susceptibility during pregnancy.

PubMed

Zheng, Xiangrong; Zhang, Weishe; Lu, Chan; Norbäck, Dan; Deng, Qihong

2018-05-01

It is well known that exposure to thermal stress during pregnancy can lead to an increased incidence of premature births. However, there is little known regarding window(s) of susceptibility during the course of a pregnancy. We attempted to identify possible windows of susceptibility in a cohort study of 3604 children in Changsha with a hot-summer and cold winter climatic characteristics. We examined the association between PTB and ambient temperature during different timing windows of pregnancy: conception month, three trimesters, birth month and entire pregnancy. We found a U-shaped relation between the prevalence of PTB and mean ambient temperature during pregnancy. Both high and low temperatures were associated with PTB risk, adjusted OR (95% CI) respectively 2.57 (1.98-3.33) and 2.39 (1.93-2.95) for 0.5 °C increase in high temperature range (>18.2°C) and 0.5°C decrease in low temperature range (< 18.2°C). Specifically, PTB was significantly associated with ambient temperature and extreme heat/cold days during conception month and the third trimester. Sensitivity analysis indicated that female fetus were more susceptible to the risk of ambient temperature. Our study indicates that the risk of preterm birth due to high or low temperature may exist early during the conception month. Copyright © 2018 Elsevier Ltd. All rights reserved.

The potential effects of climate-change-associated temperature increases on the metabolic rate of a small Afrotropical bird.

PubMed

Thompson, Lindy J; Brown, Mark; Downs, Colleen T

2015-05-15

Studies have only recently begun to underline the importance of including data on the physiological flexibility of a species when modelling its vulnerability to extinction from climate change. We investigated the effects of a 4°C increase in ambient temperature (Ta), similar to that predicted for southern Africa by the year 2080, on certain physiological variables of a 10-12 g passerine bird endemic to southern Africa, the Cape white-eye Zosterops virens. There was no significant difference in resting metabolism, body mass and intraperitoneal body temperature between birds housed indoors at 4°C above outside ambient temperature and those housed indoors at outside ambient temperature. We conclude that the physiological flexibility of Cape white-eyes will aid them in coping with the 4°C increase predicted for their range by 2080. © 2015. Published by The Company of Biologists Ltd.

Effects of ambient temperature on glucose tolerance and insulin sensitivity test outcomes in normal and obese C57 male mice.

PubMed

Dudele, Anete; Rasmussen, Gitte Marie; Mayntz, David; Malte, Hans; Lund, Sten; Wang, Tobias

2015-05-01

Mice are commonly used as animal models to study human metabolic diseases, but experiments are typically performed at room temperature, which is far below their thermoneutral zone and is associated with elevated heart rate, food intake, and energy expenditure. We set out to study how ambient temperature affects glucose tolerance and insulin sensitivity in control and obese male mice. Adult male C57BL/6J mice were housed at room temperature (23°C) for 6 weeks and fed either control or high fat diet. They were then fasted for 6 h before glucose or insulin tolerance tests were performed at 15, 20, 25, or 30°C. To ensure that behavioral thermoregulation did not counterbalance the afflicted ambient temperatures, oxygen consumption was determined on mice with the same thermoregulatory opportunities as during the tests. Decreasing ambient temperatures increased oxygen consumption and body mass loss during fasting in both groups. Mice fed high fat diet had improved glucose tolerance at 30°C and increased levels of fasting insulin followed by successive decrease of fasting glucose. However, differences between control and high-fat diet mice were present at all temperatures. Ambient temperature did not affect glucose tolerance in control group and insulin tolerance in either of the groups. Ambient temperature affects glucose metabolism in mice and this effect is phenotype specific. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Influence of p-GaN annealing on the optical and electrical properties of InGaN/GaN MQW LEDs

NASA Astrophysics Data System (ADS)

Sun, Li; Weng, Guo-En; Liang, Ming-Ming; Ying, Lei-Ying; Lv, Xue-Qin; Zhang, Jiang-Yong; Zhang, Bao-Ping

2014-06-01

Optical and electrical properties of InGaN/GaN multiple quantum wells (MQWs) light emitting diodes (LEDs) annealed in pure O2 ambient (500 °C) and pure N2 ambient (800 °C) were systematically investigated. The temperature-dependent photoluminescence measurements showed that high-temperature thermal annealing in N2 ambient can induce indium clusters in InGaN MQWs. Although the deep traps induced by indium clusters can act as localized centers for carriers, there are many more dislocations out of the trap centers due to high-temperature annealing. As a result, the radiative efficiency of the sample annealed in N2 ambient was lower than that annealed in O2 ambient at room temperature. Electrical measurements demonstrated that the LEDs annealed in O2 ambient were featured by a lower forward voltage and there was an increase of ~41% in wall-plug efficiency at 20 mA in comparison with the LEDs annealed in N2 ambient. It is thus concluded that activation of the Mg-doped p-GaN layer should be carried out at a low-temperature O2 ambient so as to obtain LEDs with better performance.

[Association between ambient temperature and hospital emergency room visits for cardiovascular diseases: a case-crossover study].

PubMed

Guo, Yu-Ming; Wang, Jia-Jia; Li, Guo-Xing; Zheng, Ya-An; He, Wichmann; Pan, Xiao-Chuan

2009-08-01

To explore the association between ambient average temperature and hospital emergency room visits for cardiovascular diseases (International Classification of Diseases, Tenth Vision ICD-10: I00 - I99) in Beijing, China. Data was collected on daily hospital emergency room visits for cardiovascular diseases from Peking University Third Hospital, including meteorological data (daily average temperature, relative humidity, wind speed, and atmospheric pressure) from the China Meteorological Data Sharing Service System, and on air pollution from the Beijing Municipal Environmental Monitoring Center. Time-stratified case-crossover design was used to analyze data on 4 seasons. After adjusting data on air pollution, 1 degree ( degrees C) increase of ambient average temperature would associate with the emergency room visits of odds ratio (ORs) as 1.282 (95%CI: 1.250 - 1.315), 1.027 (95%CI: 1.001 - 1.055), 0.661 (95%CI: 0.637 - 0.687), and 0.960 (95%CI: 0.937 - 0.984) in spring, summer, autumn, and winter respectively. After controlling the influence of relative humidity, wind speed, and atmospheric pressure, 1 degrees C increase in the ambient average temperature would be associated with the emergency room visits on ORs value as 1.423 (95%CI: 1.377 - 1.471), 1.082 (95%CI: 1.041 - 1.124), 0.633 (95%CI: 0.607 - 0.660) and 0.971 (95%CI: 0.944 - 1.000) in spring, summer, autumn, and winter respectively. These data on outcomes suggested that the elevated level of ambient temperature would increase the hospital emergency room visits for cardiovascular diseases in spring and summer while the elevated level of ambient temperature would decrease the hospital emergency room visits for the cardiovascular diseases in autumn and winter, suggesting that patients with cardiovascular diseases should pay attention to the climate change.

[Influence of daily ambient temperature on mortality and years of life lost in Chongqing].

PubMed

Li, Jing; Luo, Shuquan; Ding, Xianbin; Yang, Jun; Li, Jing; Liu, Xiaobo; Gao, Jinghong; Xu, Lei; Tang, Wenge; Liu, Qiyong

2016-03-01

To evaluate the influence of extreme ambient temperature on mortality and years of life lost (YLL) in Chongqing. The daily mortality, meteorology and air pollution index data in Chongqing from the 1(st) January 2010 to the 31(st) December 2013 were collected. Distributed lag non-linear model (DLNM) was used to assess the influence of daily ambient temperature on daily number of deaths and daily YLL respectively. The delayed and cumulative effects of extreme temperature on sex, age, and cause-specific mortality were also assessed. The relationships between ambient temperature and non-accidental, cardiovascular disease and respiratory disease mortalities and YLL were U-shaped or W-shaped. The effect of heat was obvious on that day, peaked on day 7, and lasted for two weeks, whereas the effect of cold was obvious a week later and lasted for a month. As 1 ℃ increase of ambient temperature, the cumulative relative risks (CRR) of high temperature across lag 0-7 days on non-accidental, respiratory disease and cardiovascular disease mortalities were 1.05 (95%CI: 1.03-1.07), 1.08 (95%CI: 1.05-1.11) and 1.05 (95%CI: 1.01-1.09) respectively. The effects of heat on YLL for each cause were 23.81 (95%CI: 12.31-35.31), 14.34 (95%CI: 8.98-19.70) and 4.43 (95%CI: 1.64-7.21), respectively. On cold days, 1 ℃ decrease of ambient temperature was correlated with an increase in CRR of 1.06 (95%CI: 1.04-1.08), 1.09 (95%CI:1.06-1.12) and 1.06 (95%CI: 1.02-1.11) from lag 0 to 14 for non-accidental, respiratory disease and cardiovascular disease mortalities, respectively. The estimated YLL were 23.34 (95%CI: 10.04-36.64), 16.39 (95%CI: 10.19-22.59) and 2.61 (95%CI: -0.61-5.82). People aged ≥65 years tend to have higher CRR and YLL than those aged <65 years. On high temperature days, the CRR in women was higher than that in men, while the YLL in women was lower than that in men. On low temperature days, both the CRR and YLL in women were higher than those in men. Both high and low ambient temperature have adverse health effects. People aged ≥65 years are more sensitive to both high and low ambient temperature. Younger men are more sensitive to high ambient temperature and women and elder men are sensitive to low ambient temperature. It is necessary to take targeted measures to protect the population in Chongqing from the adverse influence of extreme ambient temperature.

Low Ambient Temperature and Intracerebral Hemorrhage: The INTERACT2 Study.

PubMed

Zheng, Danni; Arima, Hisatomi; Sato, Shoichiro; Gasparrini, Antonio; Heeley, Emma; Delcourt, Candice; Lo, Serigne; Huang, Yining; Wang, Jiguang; Stapf, Christian; Robinson, Thompson; Lavados, Pablo; Chalmers, John; Anderson, Craig S

2016-01-01

Rates of acute intracerebral hemorrhage (ICH) increase in winter months but the magnitude of risk is unknown. We aimed to quantify the association of ambient temperature with the risk of ICH in the Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT2) participants on an hourly timescale. INTERACT2 was an international, open, blinded endpoint, randomized controlled trial of patients with spontaneous ICH (<6h of onset) and elevated systolic blood pressure (SBP, 150-220 mmHg) assigned to intensive (target SBP <140 mmHg) or guideline-recommended (SBP <180 mmHg) BP treatment. We linked individual level hourly temperature to baseline data of 1997 participants, and performed case-crossover analyses using a distributed lag non-linear model with 24h lag period to assess the association of ambient temperature and risk of ICH. Results were presented as overall cumulative odds ratios (ORs) and 95% CI. Low ambient temperature (≤10°C) was associated with increased risks of ICH: overall cumulative OR was 1.37 (0.99-1.91) for 10°C, 1.92 (1.31-2.81) for 0°C, 3.13 (1.89-5.19) for -10°C, and 5.76 (2.30-14.42) for -20°C, as compared with a reference temperature of 20°C.There was no clear relation of low temperature beyond three hours after exposure. Results were consistent in sensitivity analyses. Exposure to low ambient temperature within several hours increases the risk of ICH. ClinicalTrials.gov NCT00716079.

Low Ambient Temperature and Intracerebral Hemorrhage: The INTERACT2 Study

PubMed Central

Zheng, Danni; Arima, Hisatomi; Sato, Shoichiro; Gasparrini, Antonio; Heeley, Emma; Delcourt, Candice; Lo, Serigne; Huang, Yining; Wang, Jiguang; Stapf, Christian; Robinson, Thompson; Lavados, Pablo; Chalmers, John; Anderson, Craig S.

2016-01-01

Background Rates of acute intracerebral hemorrhage (ICH) increase in winter months but the magnitude of risk is unknown. We aimed to quantify the association of ambient temperature with the risk of ICH in the Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT2) participants on an hourly timescale. Methods INTERACT2 was an international, open, blinded endpoint, randomized controlled trial of patients with spontaneous ICH (<6h of onset) and elevated systolic blood pressure (SBP, 150–220 mmHg) assigned to intensive (target SBP <140 mmHg) or guideline-recommended (SBP <180 mmHg) BP treatment. We linked individual level hourly temperature to baseline data of 1997 participants, and performed case-crossover analyses using a distributed lag non-linear model with 24h lag period to assess the association of ambient temperature and risk of ICH. Results were presented as overall cumulative odds ratios (ORs) and 95% CI. Results Low ambient temperature (≤10°C) was associated with increased risks of ICH: overall cumulative OR was 1.37 (0.99–1.91) for 10°C, 1.92 (1.31–2.81) for 0°C, 3.13 (1.89–5.19) for -10°C, and 5.76 (2.30–14.42) for -20°C, as compared with a reference temperature of 20°C.There was no clear relation of low temperature beyond three hours after exposure. Results were consistent in sensitivity analyses. Conclusions Exposure to low ambient temperature within several hours increases the risk of ICH. Trial Registration ClinicalTrials.gov NCT00716079 PMID:26859491

Preservation of Biospecimens at Ambient Temperature: Special Focus on Nucleic Acids and Opportunities for the Biobanking Community.

PubMed

Muller, Rolf; Betsou, Fay; Barnes, Michael G; Harding, Keith; Bonnet, Jacques; Kofanova, Olga; Crowe, John H

2016-04-01

Several approaches to the preservation of biological materials at ambient temperature and the relative impact on sample stability and degradation are reviewed, with a focus on nucleic acids. This appraisal is undertaken within the framework of biobank risk, quality management systems, and accreditation, with a view to assessing how best to apply ambient temperature sample storage to ensure stability, reduce costs, improve handling logistics, and increase the efficiency of biobank procedures.

Ambient Temperature and Cerebrovascular Hemodynamics in the Elderly

PubMed Central

Pan, Wen-Chi; Eliot, Melissa N.; Koutrakis, Petros; Coull, Brent A.; Sorond, Farzaneh A.; Wellenius, Gregory A.

2015-01-01

Background and Purpose Some prior studies have linked ambient temperature with risk of cerebrovascular events. If causal, the pathophysiologic mechanisms underlying this putative association remain unknown. Temperature-related changes in cerebral vascular function may play a role, but this hypothesis has not been previously evaluated. Methods We evaluated the association between ambient temperature and cerebral vascular function among 432 participants ≥65 years old from the MOBILIZE Boston Study with data on cerebrovascular blood flow, cerebrovascular resistance, and cerebrovascular reactivity in the middle cerebral artery. We used linear regression models to assess the association of mean ambient temperature in the previous 1 to 28 days with cerebrovascular hemodynamics adjusting for potential confounding factors. Results A 10°C increase in the 21-day moving average of ambient temperature was associated with a 10.1% (95% confidence interval [CI], 2.2%, 17.3%) lower blood flow velocity, a 9.0% (95% CI, 0.7%, 18.0%) higher cerebrovascular resistance, and a 15.3% (95%CI, 2.7%, 26.4%) lower cerebral vasoreactivity. Further adjustment for ozone and fine particulate matter (PM2.5) did not materially alter the results. However, we found statistically significant interactions between ambient temperature and PM2.5 such that the association between temperature and blood flow velocity was attenuated at higher levels of PM2.5. Conclusions In this elderly population, we found that ambient temperature was negatively associated with cerebral blood flow velocity and cerebrovascular vasoreactivity and positively associated with cerebrovascular resistance. Changes in vascular function may partly underlie the observed associations between ambient temperature and risk of cerebrovascular events. PMID:26258469

Ambient Temperature and Cerebrovascular Hemodynamics in the Elderly.

PubMed

Pan, Wen-Chi; Eliot, Melissa N; Koutrakis, Petros; Coull, Brent A; Sorond, Farzaneh A; Wellenius, Gregory A

2015-01-01

Some prior studies have linked ambient temperature with risk of cerebrovascular events. If causal, the pathophysiologic mechanisms underlying this putative association remain unknown. Temperature-related changes in cerebral vascular function may play a role, but this hypothesis has not been previously evaluated. We evaluated the association between ambient temperature and cerebral vascular function among 432 participants ≥65 years old from the MOBILIZE Boston Study with data on cerebrovascular blood flow, cerebrovascular resistance, and cerebrovascular reactivity in the middle cerebral artery. We used linear regression models to assess the association of mean ambient temperature in the previous 1 to 28 days with cerebrovascular hemodynamics adjusting for potential confounding factors. A 10°C increase in the 21-day moving average of ambient temperature was associated with a 10.1% (95% confidence interval [CI], 2.2%, 17.3%) lower blood flow velocity, a 9.0% (95% CI, 0.7%, 18.0%) higher cerebrovascular resistance, and a 15.3% (95%CI, 2.7%, 26.4%) lower cerebral vasoreactivity. Further adjustment for ozone and fine particulate matter (PM2.5) did not materially alter the results. However, we found statistically significant interactions between ambient temperature and PM2.5 such that the association between temperature and blood flow velocity was attenuated at higher levels of PM2.5. In this elderly population, we found that ambient temperature was negatively associated with cerebral blood flow velocity and cerebrovascular vasoreactivity and positively associated with cerebrovascular resistance. Changes in vascular function may partly underlie the observed associations between ambient temperature and risk of cerebrovascular events.

The effects of co-administration of 3,4-methylenedioxymethamphetamine ("ecstasy") or para-methoxyamphetamine and moclobemide at elevated ambient temperatures on striatal 5-HT, body temperature and behavior in rats.

PubMed

Stanley, N; Salem, A; Irvine, R J

2007-04-25

We have recently demonstrated that co-administration of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") with the reversible monoamine oxidase type A (MAO-A) inhibitor moclobemide at an ambient temperature of 22 degrees C significantly increases striatal 5-HT outflow and 5-HT-mediated behaviors. In the present study, using microdialysis, we examined the effects of co-administration of MDMA or para-methoxyamphetamine (PMA) with moclobemide on striatal 5-HT outflow at the elevated ambient temperatures of 30 degrees C. Samples were collected every 30 min for 4 h and analyzed by high-performance liquid chromatography assay with electrochemical detection (HPLC-ED). 5-HT-mediated effects on body temperature and behavior were also recorded. Rats were treated with either saline or 20 mg/kg (i.p.) moclobemide, followed by 10 mg/kg (i.p.) MDMA, 10 mg/kg (i.p.) PMA or saline 60 min later. Both MDMA and PMA produced significant increases in 5-HT outflow (370% peak and 309% peak, respectively, P<0.05). MDMA and PMA significantly increased body temperature (+2.0 degrees C and +2.1 degrees C, respectively, P<0.01) and drug-related behaviors (P<0.05). When MDMA or PMA was co-administered with moclobemide, additional significant increases were seen in 5-HT outflow (850% peak, P<0.01 and 1450% peak, P<0.001, respectively) and only MDMA showed additional significant increase in body temperature (+5.0 degrees C, P<0.001). No additional increases were seen in behavioral activity. When moclobemide was co-administered with MDMA, sustained increases in body temperature were recorded that were significantly higher than with MDMA alone and such increases were not observed in our previous study at normal room temperature. Our results suggest greater risk of MDMA-induced adverse effects on body temperature regulation, compared with PMA, when used in combination with moclobemide at elevated ambient temperatures.

Effect of Socioeconomic Status and Underlying Disease on the Association between Ambient Temperature and Ischemic Stroke.

PubMed

Cho, Seong Kyung; Sohn, Jungwoo; Cho, Jaelim; Noh, Juhwan; Ha, Kyoung Hwa; Choi, Yoon Jung; Pae, Sangjoon; Kim, Changsoo; Shin, Dong Chun

2018-07-01

Inconsistent findings have been reported regarding the effect of ambient temperature on ischemic stroke. Furthermore, little is known about how underlying disease and low socioeconomic status influence the association. We, therefore, investigated the relationship between ambient temperature and emergency department (ED) visits for ischemic stroke, and aimed to identify susceptible populations. Using medical claims data, we identified ED visits for ischemic stroke during 2005-2009 in Seoul, Korea. We conducted piecewise linear regression analyses to find optimum ambient temperature thresholds in summer and winter, and estimated the relative risks (RR) and 95% confidence intervals (CI) per a 1°C increase in temperature above/below the thresholds, adjusting for relative humidity, holidays, day of the week, and air pollutant levels. There were 63564 ED visits for ischemic stroke. In summer, the risk of ED visits for ischemic stroke was not significant, with the threshold at 26.8°C. However, the RRs were 1.055 (95% CI, 1.006-1.106) above 25.0°C in medical aid beneficiaries and 1.044 (1.007-1.082) above 25.8°C in patients with diabetes. In winter, the risk of ED visits for ischemic stroke significantly increased as the temperature decreased above the threshold at 7.2°C. This inverse association was significant also in patients with hypertension and diabetes mellitus above threshold temperatures. Ambient temperature increases above a threshold were positively associated with ED visits for ischemic stroke in patients with diabetes and medical aid beneficiaries in summer. In winter, temperature, to a point, and ischemic stroke visits were inversely associated. © Copyright: Yonsei University College of Medicine 2018.

Brachial artery responses to ambient pollution, temperature, and humidity in people with type 2 diabetes: a repeated-measures study.

PubMed

Zanobetti, Antonella; Luttmann-Gibson, Heike; Horton, Edward S; Cohen, Allison; Coull, Brent A; Hoffmann, Barbara; Schwartz, Joel D; Mittleman, Murray A; Li, Yongsheng; Stone, Peter H; de Souza, Celine; Lamparello, Brooke; Koutrakis, Petros; Gold, Diane R

2014-03-01

Extreme weather and air pollution are associated with increased cardiovascular risk in people with diabetes. In a population with diabetes, we conducted a novel assessment of vascular brachial artery responses both to ambient pollution and to weather (temperature and water vapor pressure, a measure of humidity). Sixty-four 49- to 85-year-old Boston residents with type 2 diabetes completed up to five study visits (279 repeated measures). Brachial artery diameter (BAD) was measured by ultrasound before and after brachial artery occlusion [i.e., flow-mediated dilation (FMD)] and before and after nitroglycerin-mediated dilation (NMD). Ambient concentrations of fine particulate mass (PM2.5), black carbon (BC), organic carbon (OC), elemental carbon, particle number, and sulfate were measured at our monitoring site; ambient concentrations of carbon monoxide, nitrogen dioxide, and ozone were obtained from state monitors. Particle exposure in the home and during each trip to the clinic (home/trip exposure) was measured continuously and as a 5-day integrated sample. We used linear models with fixed effects for participants, adjusting for date, season, temperature, and water vapor pressure on the day of each visit, to estimate associations between our outcomes and interquartile range increases in exposure. Baseline BAD was negatively associated with particle pollution, including home/trip-integrated BC (-0.02 mm; 95% CI: -0.04, -0.003, for a 0.28 μg/m3 increase in BC), OC (-0.08 mm; 95% CI: -0.14, -0.03, for a 1.61 μg/m3 increase) as well as PM2.5, 5-day average ambient PM2.5, and BC. BAD was positively associated with ambient temperature and water vapor pressure. However, exposures were not consistently associated with FMD or NMD. Brachial artery diameter, a predictor of cardiovascular risk, decreased in association with particle pollution and increased in association with ambient temperature in our study population of adults with type 2 diabetes. Zanobetti A, Luttmann-Gibson H, Horton ES, Cohen A, Coull BA, Hoffmann B, Schwartz JD, Mittleman MA, Li Y, Stone PH, de Souza C, Lamparello B, Koutrakis P, Gold DR. 2014. Brachial artery responses to ambient pollution, temperature, and humidity in people with type 2 diabetes: a repeated-measures study. Environ Health Perspect 122:242-248; http://dx.doi.org/10.1289/ehp.1206136.

Wood properties of Scots pines (Pinus sylvestris) grown at elevated temperature and carbon dioxide concentration.

PubMed

Kilpeläinen, Antti; Peltola, Heli; Ryyppö, Aija; Sauvala, Kari; Laitinen, Kaisa; Kellomäki, Seppo

2003-09-01

Impacts of elevated temperature and carbon dioxide concentration ([CO2]) on wood properties of 15-year-old Scots pines (Pinus sylvestris L.) grown under conditions of low nitrogen supply were investigated in open-top chambers. The treatments consisted of (i) ambient temperature and ambient [CO2] (AT+AC), (ii) ambient temperature and elevated [CO2] (AT+EC), (iii) elevated temperature and ambient [CO2] (ET+AC) and (iv) elevated temperature and elevated [CO2] (ET+EC). Wood properties analyzed for the years 1992-1994 included ring width, early- and latewood width and their proportions, intra-ring wood density (minimum, maximum and mean, as well as early- and latewood densities), mean fiber length and chemical composition of the wood (cellulose, hemicellulose, lignin and acetone extractive concentration). Absolute radial growth over the 3-year period was 54% greater in AT+EC trees and 30 and 25% greater in ET+AC and ET+EC trees, respectively, than in AT+AC trees. Neither elevated temperature nor elevated [CO2] had a statistically significant effect on ring width, early- and latewood widths or their proportions. Both latewood density and maximum intra-ring density were increased by elevated [CO2], whereas fiber length was increased by elevated temperature. Hemicellulose concentration decreased and lignin concentration increased significantly in response to elevated temperature. There were no statistically significant interaction effects of elevated temperature and elevated [CO2] on the wood properties, except on earlywood density.

Increased visceral tissue perfusion with heated, humidified carbon dioxide insufflation during open abdominal surgery in a rodent model.

PubMed

Robson, Jonathan P; Kokhanenko, Pavlo; Marshall, Jean K; Phillips, Anthony R; van der Linden, Jan

2018-01-01

Tissue perfusion during surgery is important in reducing surgical site infections and promoting healing. This study aimed to determine if insufflation of the open abdomen with heated, humidified (HH) carbon dioxide (CO2) increased visceral tissue perfusion and core body temperature during open abdominal surgery in a rodent model. Using two different rodent models of open abdominal surgery, visceral perfusion and core temperature were measured. Visceral perfusion was investigated using a repeated measures crossover experiment with rodents receiving the same sequence of two alternating treatments: exposure to ambient air (no insufflation) and insufflation with HH CO2. Core body temperature was measured using an independent experimental design with three treatment groups: ambient air, HH CO2 and cold, dry (CD) CO2. Visceral perfusion was measured by laser speckle contrast analysis (LASCA) and core body temperature was measured with a rectal thermometer. Insufflation with HH CO2 into a rodent open abdominal cavity significantly increased visceral tissue perfusion (2.4 perfusion units (PU)/min (95% CI 1.23-3.58); p<0.0001) compared with ambient air, which significantly reduced visceral blood flow (-5.20 PU/min (95% CI -6.83- -3.58); p<0.0001). Insufflation of HH CO2 into the open abdominal cavity significantly increased core body temperature (+1.15 ± 0.14°C) compared with open cavities exposed to ambient air (-0.65 ± 0.52°C; p = 0.037), or cavities insufflated with CD CO2 (-0.73 ± 0.33°C; p = 0.006). Abdominal visceral temperatures also increased with HH CO2 insufflation compared with ambient air or CD CO2, as shown by infrared thermography. This study reports for the first time the use of LASCA to measure visceral perfusion in open abdominal surgery and shows that insufflation of open abdominal cavities with HH CO2 significantly increases visceral tissue perfusion and core body temperature.

Effects of Cold Temperature and Ethanol Content on VOC Emissions from Light-Duty Gasoline Vehicles.

PubMed

George, Ingrid J; Hays, Michael D; Herrington, Jason S; Preston, William; Snow, Richard; Faircloth, James; George, Barbara Jane; Long, Thomas; Baldauf, Richard W

2015-11-03

Emissions of speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs), were measured in vehicle exhaust from three light-duty spark ignition vehicles operating on summer and winter grade gasoline (E0) and ethanol blended (E10 and E85) fuels. Vehicle testing was conducted using a three-phase LA92 driving cycle in a temperature-controlled chassis dynamometer at two ambient temperatures (-7 and 24 °C). The cold start driving phase and cold ambient temperature increased VOC and MSAT emissions up to several orders of magnitude compared to emissions during other vehicle operation phases and warm ambient temperature testing, respectively. As a result, calculated ozone formation potentials (OFPs) were 7 to 21 times greater for the cold starts during cold temperature tests than comparable warm temperature tests. The use of E85 fuel generally led to substantial reductions in hydrocarbons and increases in oxygenates such as ethanol and acetaldehyde compared to E0 and E10 fuels. However, at the same ambient temperature, the VOC emissions from the E0 and E10 fuels and OFPs from all fuels were not significantly different. Cold temperature effects on cold start MSAT emissions varied by individual MSAT compound, but were consistent over a range of modern spark ignition vehicles.

A time series analysis of the relationship of ambient temperature and common bacterial enteric infections in two Canadian provinces

NASA Astrophysics Data System (ADS)

Fleury, Manon; Charron, Dominique F.; Holt, John D.; Allen, O. Brian; Maarouf, Abdel R.

2006-07-01

The incidence of enteric infections in the Canadian population varies seasonally, and may be expected to be change in response to global climate changes. To better understand any potential impact of warmer temperature on enteric infections in Canada, we investigated the relationship between ambient temperature and weekly reports of confirmed cases of three pathogens in Canada: Salmonella, pathogenic Escherichia coli and Campylobacter, between 1992 and 2000 in two Canadian provinces. We used generalized linear models (GLMs) and generalized additive models (GAMs) to estimate the effect of seasonal adjustments on the estimated models. We found a strong non-linear association between ambient temperature and the occurrence of all three enteric pathogens in Alberta, Canada, and of Campylobacter in Newfoundland-Labrador. Threshold models were used to quantify the relationship of disease and temperature with thresholds chosen from 0 to -10°C depending on the pathogen modeled. For Alberta, the log relative risk of Salmonella weekly case counts increased by 1.2%, Campylobacter weekly case counts increased by 2.2%, and E. coli weekly case counts increased by 6.0% for every degree increase in weekly mean temperature. For Newfoundland-Labrador the log relative risk increased by 4.5% for Campylobacter for every degree increase in weekly mean temperature.

No relevant impact of ambient temperature on disability measurements in a large cohort of patients with multiple sclerosis.

PubMed

Stellmann, J-P; Young, K L; Vettorazzi, E; Pöttgen, J; Heesen, C

2017-06-01

Many patients with multiple sclerosis (MS) report a worsening of symptoms due to high ambient temperatures, but objective data about this association are rare and contradictory. The aim of this study was to investigate the influence of ambient temperature on standard clinical tests. We extracted the Symbol Digit Modality Test, Nine Hole Peg Test, Timed 25 Foot Walk (T25FW), Timed Tandem Walk, Expanded Disability Status Scale (EDSS) and quality-of-life items on cognition, fatigue and depression from our clinical database and matched them to historical temperatures. We used linear mixed-effect models to investigate the association between temperature and outcomes. A total of 1254 patients with MS (mean age, 42.7 years; 69.9% females; 52.1% relapsing-remitting MS, mean EDSS, 3.8) had 5751 assessments between 1996 and 2012. We observed a worsening in the T25FW with higher ambient temperatures in moderately disabled patients (EDSS ≥ 4) but not in less disabled patients. However, an increase of 10°C prolonged the T25FW by just 0.4 s. Other outcomes were not associated with ambient temperatures. Higher ambient temperature might compromise walking capabilities in patients with MS with a manifest walking impairment. However, effects are small and not detectable in mildly disabled patients. Hand function, cognition, mood and fatigue do not appear to be correlated with ambient temperature. © 2017 EAN.

Ambient temperature shapes reproductive output during pregnancy and lactation in the common vole (Microtus arvalis): a test of the heat dissipation limit theory.

PubMed

Simons, Mirre J P; Reimert, Inonge; van der Vinne, Vincent; Hambly, Catherine; Vaanholt, Lobke M; Speakman, John R; Gerkema, Menno P

2011-01-01

The heat dissipation limit theory suggests that heat generated during metabolism limits energy intake and, thus, reproductive output. Experiments in laboratory strains of mice and rats, and also domestic livestock generally support this theory. Selection for many generations in the laboratory and in livestock has increased litter size or productivity in these animals. To test the wider validity of the heat dissipation limit theory, we studied common voles (Microtus arvalis), which have small litter sizes by comparison with mice and rats, and regular addition of wild-caught individuals of this species to our laboratory colony ensures a natural genetic background. A crossover design of ambient temperatures (21 and 30°C) during pregnancy and lactation was used. High ambient temperature during lactation decreased milk production, slowing pup growth. The effect on pup growth was amplified when ambient temperature was also high during pregnancy. Shaving fur off dams at 30°C resulted in faster growth of pups; however, no significant increase in food intake and or milk production was detected. With increasing litter size (natural and enlarged), asymptotic food intake during lactation levelled off in the largest litters at both 21 and 30°C. Interestingly, the effects of lactation temperature on pup growth where also observed at smaller litter sizes. This suggests that vole dams trade-off costs associated with hyperthermia during lactation with the yield from investment in pup growth. Moreover, pup survival was higher at 30°C, despite lower growth, probably owing to thermoregulatory benefits. It remains to be seen how the balance is established between the negative effect of high ambient temperature on maternal milk production and pup growth (and/or future reproduction of the dam) and the positive effect of high temperatures on pup survival. This balance ultimately determines the effect of different ambient temperatures on reproductive success.

Theoretical and Experimental Investigations on Droplet Evaporation and Droplet Ignition at High Pressures

NASA Technical Reports Server (NTRS)

Ristau, R.; Nagel, U.; Iglseder, H.; Koenig, J.; Rath, H. J.; Normura, H.; Kono, M.; Tanabe, M.; Sato, J.

1993-01-01

The evaporation of fuel droplets under high ambient pressure and temperature in normal gravity and microgravity has been investigated experimentally. For subcritical ambient conditions, droplet evaporation after a heat-up period follows the d(exp 2)-law. For all data the evaporation constant increases as the ambient temperature increases. At identical ambient conditions the evaporation constant under microgravity is smaller compared to normal gravity. This effect can first be observed at 1 bar and increases with ambient pressure. Preliminary experiments on ignition delay for self-igniting fuel droplets have been performed. Above a 1 s delay time, at identical ambient conditions, significant differences in the results of the normal and microgravity data are observed. Self-ignition occurs within different temperature ranges due to the influence of gravity. The time dependent behavior of the droplet is examined theoretically. In the calculations two different approaches for the gas phase are applied. In the first approach the conditions at the interface are given using a quasi steady theory approximation. The second approach uses a set of time dependent governing equations for the gas phase which are then evaluated. In comparison, the second model shows a better agreement with the drop tower experiments. In both cases a time dependent gasification rate is observed.

Differential effects of environment-induced changes in body temperature on modafinil’s actions against methamphetamine-induced striatal toxicity in mice

PubMed Central

Raineri, Mariana; González, Betina; Echeto, Celeste Rivero; Muñiz, Javier A.; Gutierrez, María Laura; Ghanem, Carolina I.; Cadet, Jean Lud; García-Rill, Edgar; Urbano, Francisco J.; Veronica, Bisagno

2015-01-01

Methamphetamine (METH) exposure can produce hyperthermia that might lead to toxicity and death. Modafinil is a wake-promoting compound that is also been prescribed off-label to treat METH dependence. Modafinil has shown neuroprotective properties against METH harmful effects in animal models. The goal of the present study was to test if the prevention of hyperthermia might play a role on the neuroprotective actions of modafinil against METH toxicity using various ambient temperatures. METH was administered to female C57BL/6 mice in a binge regimen: 4 × 5 mg/kg , 2h apart; modafinil (90mg/kg) was injected twice, 1h before first and fourth METH injections. Drugs were given at cold ambient temperature (14 °C) or hot ambient temperature (29 °C). Body temperature was measured during treatments. Brains were dissected out six days after treatments and processed for TH, DAT, GFAP and c-Fos immunohistochemistry. Exposure to hot ambient temperature exacerbated METH toxicity evidenced by sriatal reductions in TH and DAT and increased GFAP immmunoreactivity. Modafinil counteracted reductions in TH and DAT, but failed to block astroglial activation. At both ambient temperatures tested modafinil did induce increments in GFAP, but the magnitude was significantly lower than the one induced by METH. Both drugs induced increases in c-Fos positive nuclei; modafinil did not block this effect. Our results suggest that protective effects of modafinil against METH-induced neurotoxicity may be dependent, in part, to its hypothermic effects. Nevertheless, modafinil maintained some protective properties on METH-induced alterations in the striatum at different ambient temperatures. PMID:25261212

Differential effects of environment-induced changes in body temperature on modafinil's actions against methamphetamine-induced striatal toxicity in mice.

PubMed

Raineri, Mariana; González, Betina; Rivero-Echeto, Celeste; Muñiz, Javier A; Gutiérrez, María Laura; Ghanem, Carolina I; Cadet, Jean Lud; García-Rill, Edgar; Urbano, Francisco J; Bisagno, Veronica

2015-01-01

Methamphetamine (METH) exposure can produce hyperthermia that might lead to toxicity and death. Modafinil is a wake-promoting compound that is also been prescribed off-label to treat METH dependence. Modafinil has shown neuroprotective properties against METH harmful effects in animal models. The goal of the present study was to test if the prevention of hyperthermia might play a role on the neuroprotective actions of modafinil against METH toxicity using various ambient temperatures. METH was administered to female C57BL/6 mice in a binge regimen: 4 × 5 mg/kg, 2 h apart; modafinil (90 mg/kg) was injected twice, 1 h before first and fourth METH injections. Drugs were given at cold ambient temperature (14 °C) or hot ambient temperature (29 °C). Body temperature was measured during treatments. Brains were dissected out 6 days after treatments and processed for tyrosine hydroxylase (TH), dopamine transporter (DAT), GFAP and c-Fos immunohistochemistry. Exposure to hot ambient temperature exacerbated METH toxicity evidenced by striatal reductions in TH and DAT and increased GFAP immmunoreactivity. Modafinil counteracted reductions in TH and DAT, but failed to block astroglial activation. At both ambient temperatures tested modafinil did induce increments in GFAP, but the magnitude was significantly lower than the one induced by METH. Both drugs induced increases in c-Fos positive nuclei; modafinil did not block this effect. Our results suggest that protective effects of modafinil against METH-induced neurotoxicity may be dependent, in part, to its hypothermic effects. Nevertheless, modafinil maintained some protective properties on METH-induced alterations in the striatum at different ambient temperatures.

Effects of a whole-body spandex garment on rectal temperature and oxygen consumption in healthy dogs.

PubMed

Reimer, S Brent; Schulz, Kurt S; Mason, David R; Jones, James H

2004-01-01

To determine whether a full-body spandex garment would alter rectal temperatures of healthy dogs at rest in cool and warm environments. Prospective study. 10 healthy dogs. Each dog was evaluated at a low (20 degrees to 25 degrees C [68 degrees to 77 degrees F]) or high (30 degrees to 35 degrees C [86 degrees to 95 degrees F]) ambient temperature while wearing or not wearing a commercially available whole-body spandex garment designed for dogs. Oxygen consumption was measured by placing dogs in a flow-through indirect calorimeter for 90 to 120 minutes. Rectal temperature was measured before dogs were placed in the calorimeter and after they were removed. Rectal temperature increased significantly more at the higher ambient temperature than at the lower temperature and when dogs were not wearing the garment than when they were wearing it. The specific rate of oxygen consumption was significantly higher at the lower ambient temperature than at the higher temperature. Results suggest that wearing a snug spandex body garment does not increase the possibility that dogs will overheat while in moderate ambient temperatures. Instead, wearing such a garment may enable dogs to better maintain body temperature during moderate heat loading. These results suggest that such garments might be used for purposes such as wound or suture protection without causing dogs to overheat.

Outdoor temperature is associated with serum HDL and LDL.

PubMed

Halonen, Jaana I; Zanobetti, Antonella; Sparrow, David; Vokonas, Pantel S; Schwartz, Joel

2011-02-01

While exposures to high and low air temperatures are associated with cardiovascular mortality, the underlying mechanisms are poorly understood. The risk factors for cardiovascular disease include high levels of total cholesterol and low-density lipoprotein (LDL), and low levels of high-density lipoprotein (HDL). We investigated whether temperature was associated with changes in circulating lipid levels, and whether this might explain part of the association with increased cardiovascular events. The study cohort consisted of 478 men in the greater Boston area with a mean age of 74.2 years. They visited the clinic every 3-5 years between 1995 and 2008 for physical examination and to complete questionnaires. We excluded from analyses all men taking statin medication and all days with missing data, resulting in a total of 862 visits. Associations between three temperature variables (ambient, apparent, and dew point temperature) and serum lipid levels (total cholesterol, HDL, LDL, and triglycerides) were studied with linear mixed models that included possible confounders such as air pollution and a random intercept for each subject. We found that HDL decreased -1.76% (95% CI: from -3.17 to -0.32, lag 2 days), and -5.58% (95% CI: from -8.87 to -2.16, moving average of 4 weeks) for each 5°C increase in mean ambient temperature. For the same increase in mean ambient temperature, LDL increased by 1.74% (95% CI: 0.07-3.44, lag 1 day) and 1.87% (95% CI: 0.14-3.63, lag 2 days). These results were also similar for apparent and dew point temperatures. No changes were found in total cholesterol or triglycerides in relation to temperature increase. Changes in HDL and LDL levels associated with an increase in ambient temperature may be among the underlying mechanisms of temperature-related cardiovascular mortality. Copyright © 2010 Elsevier Inc. All rights reserved.

Development of rabbit embryos during a 96-h period of in vitro culture after superovulatory treatment under conditions of elevated ambient temperature.

PubMed

Cheng, H; Dooley, M P; Hopkins, S M; Anderson, L L; Yibchok-anun, S; Hsu, W H

1999-08-16

The effects of elevated ambient temperature on the response to exogenous gonadotropins were evaluated in female New Zealand White rabbits exposed to 33+/-1 degrees C (mean +/- SE) and 10-30% relative humidity (8 h/day) during a 5-day period. Does were treated with pFSH (0.3 mg/0.3 ml Standard Armour) twice daily during three consecutive days with a minimum interval of 8 h between injections. Six hours after the last FSH injection all does were removed from the experimental chamber, given hCG (25 IU/kg) and paired overnight. Nineteen hours after pairing, embryos were flushed from the reproductive tracts, evaluated, and subjected to in vitro culture during a 96-h period. The ovulatory responses to exogenous gonadotropins and fertilization rates did not differ significantly under conditions of elevated ambient temperature, whereas fewer blastocysts and increased number of degenerate embryos were observed after culture. We conclude that although hyperthermia was induced during exposure to elevated ambient temperature, it did not alter the ovulatory responses to gonadotropin treatment and plasma concentrations of FSH and LH compared with does in a thermoneutral environment. Exposure of donor rabbits to elevated ambient temperature before mating, however, increased embryonic degeneration.

Locomotor Activity and Body Temperature Patterns over a Temperature Gradient in the Highveld Mole-Rat (Cryptomys hottentotus pretoriae).

PubMed

Haupt, Meghan; Bennett, Nigel C; Oosthuizen, Maria K

2017-01-01

African mole-rats are strictly subterranean mammals that live in extensive burrow systems. High humidity levels in the burrows prevent mole-rats from thermoregulating using evaporative cooling. However, the relatively stable environment of the burrows promotes moderate temperatures and small daily temperature fluctuations. Mole-rats therefore display a relatively wide range of thermoregulation abilities. Some species cannot maintain their body temperatures at a constant level, whereas others employ behavioural thermoregulation. Here we test the effect of ambient temperature on locomotor activity and body temperature, and the relationship between the two parameters, in the highveld mole-rat. We exposed mole-rats to a 12L:12D and a DD light cycle at ambient temperatures of 30°C, 25°C and 20°C while locomotor activity and body temperature were measured simultaneously. In addition, we investigated the endogenous rhythms of locomotor activity and body temperature at different ambient temperatures. Mole-rats displayed nocturnal activity at all three ambient temperatures and were most active at 20°C, but least active at 30°C. Body temperature was highest at 30°C and lowest at 20°C, and the daily cycle was highly correlated with locomotor activity. We show that the mole-rats have endogenous rhythms for both locomotor activity and body temperature. However, the endogenous body temperature rhythm appears to be less robust compared to the locomotor activity rhythm. Female mole-rats appear to be more sensitive to temperature changes than males, increased heterothermy is evident at lower ambient temperatures, whilst males show smaller variation in their body temperatures with changing ambient temperatures. Mole-rats may rely more heavily on behavioural thermoregulation as it is more energy efficient in an already challenging environment.

Locomotor Activity and Body Temperature Patterns over a Temperature Gradient in the Highveld Mole-Rat (Cryptomys hottentotus pretoriae)

PubMed Central

Haupt, Meghan; Bennett, Nigel C.

2017-01-01

African mole-rats are strictly subterranean mammals that live in extensive burrow systems. High humidity levels in the burrows prevent mole-rats from thermoregulating using evaporative cooling. However, the relatively stable environment of the burrows promotes moderate temperatures and small daily temperature fluctuations. Mole-rats therefore display a relatively wide range of thermoregulation abilities. Some species cannot maintain their body temperatures at a constant level, whereas others employ behavioural thermoregulation. Here we test the effect of ambient temperature on locomotor activity and body temperature, and the relationship between the two parameters, in the highveld mole-rat. We exposed mole-rats to a 12L:12D and a DD light cycle at ambient temperatures of 30°C, 25°C and 20°C while locomotor activity and body temperature were measured simultaneously. In addition, we investigated the endogenous rhythms of locomotor activity and body temperature at different ambient temperatures. Mole-rats displayed nocturnal activity at all three ambient temperatures and were most active at 20°C, but least active at 30°C. Body temperature was highest at 30°C and lowest at 20°C, and the daily cycle was highly correlated with locomotor activity. We show that the mole-rats have endogenous rhythms for both locomotor activity and body temperature. However, the endogenous body temperature rhythm appears to be less robust compared to the locomotor activity rhythm. Female mole-rats appear to be more sensitive to temperature changes than males, increased heterothermy is evident at lower ambient temperatures, whilst males show smaller variation in their body temperatures with changing ambient temperatures. Mole-rats may rely more heavily on behavioural thermoregulation as it is more energy efficient in an already challenging environment. PMID:28072840

Influence of low ambient temperature on epitympanic temperature measurement: a prospective randomized clinical study.

PubMed

Strapazzon, Giacomo; Procter, Emily; Putzer, Gabriel; Avancini, Giovanni; Dal Cappello, Tomas; Überbacher, Norbert; Hofer, Georg; Rainer, Bernhard; Rammlmair, Georg; Brugger, Hermann

2015-11-05

Epitympanic temperature (Tty) measured with thermistor probes correlates with core body temperature (Tcore), but the reliability of measurements at low ambient temperature is unknown. The aim of this study was to determine if commercially-available thermistor-based Tty reflects Tcore in low ambient temperature and if Tty is influenced by insulation of the ear. Thirty-one participants (two females) were exposed to room (23.2 ± 0.4 °C) and low (-18.7 ± 1.0 °C) ambient temperature for 10 min using a randomized cross-over design. Tty was measured using an epitympanic probe (M1024233, GE Healthcare Finland Oy) and oesophageal temperature (Tes) with an oesophageal probe (M1024229, GE Healthcare Finland Oy) inserted into the lower third of the oesophagus. Ten participants wore ear protectors (Arton 2200, Emil Lux GmbH & Co. KG, Wermelskirchen, Switzerland) to insulate the ear from ambient air. During exposure to room temperature, mean Tty increased from 33.4 ± 1.5 to 34.2 ± 0.8 °C without insulation of the ear and from 35.0 ± 0.8 to 35.5 ± 0.7 °C with insulation. During exposure to low ambient temperature, mean Tty decreased from 32.4 ± 1.6 to 28.5 ± 2.0 °C without insulation and from 35.6 ± 0.6 to 35.2 ± 0.9 °C with insulation. The difference between Tty and Tes at low ambient temperature was reduced by 82% (from 7.2 to 1.3 °C) with insulation of the ear. Epitympanic temperature measurements are influenced by ambient temperature and deviate from Tes at room and low ambient temperature. Insulating the ear with ear protectors markedly reduced the difference between Tty and Tes and improved the stability of measurements. The use of models to correct Tty may be possible, but results should be validated in larger studies.

Short communication: Changes in body temperature of calves up to 2 months of age as affected by time of day, age, and ambient temperature.

PubMed

Hill, T M; Bateman, H G; Suarez-Mena, F X; Dennis, T S; Schlotterbeck, R L

2016-11-01

Extensive measurements of calf body temperature are limited in the literature. In this study, body temperatures were collected by taping a data logger to the skin over the tail vein opposing the rectum of Holstein calves between 4 and 60d of age during 3 different periods of the summer and fall. The summer period was separated into moderate (21-33°C average low to high) and hot (25-37°C) periods, whereas the fall exhibited cool (11-19°C) ambient temperatures. Tail temperatures were compared in a mixed model ANOVA using ambient temperature, age of calf, and time of day (10-min increments) as fixed effects and calf as a random effect. Measures within calf were modeled as repeated effects of type autoregressive 1. Calf temperature increased 0.0325°C (±0.00035) per 1°C increase in ambient temperature. Body temperature varied in a distinct, diurnal pattern with time of day, with body temperatures being lowest around 0800h and highest between 1700 and 2200h. During periods of hot weather, the highest calf temperature was later in the day (~2200h). Calf minimum, maximum, and average body temperatures were all higher in hot than in moderate periods and higher in moderate than in cool periods. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Interactive effect of elevated CO2 and temperature on coral physiology

NASA Astrophysics Data System (ADS)

Grottoli, A. G.; Cai, W.; Warner, M.; Melman, T.; Schoepf, V.; Baumann, J.; Matsui, Y.; Pettay, D. T.; Hoadley, K.; Xu, H.; Wang, Y.; Li, Q.; Hu, X.

2011-12-01

Increases in ocean acidification and temperature threaten coral reefs globally. However, the interactive effect of both lower pH and higher temperature on coral physiology and growth are poorly understood. Here, we present preliminary findings from a replicated controlled experiment where four species of corals (Acorpora millepora, Pocillopora damicornis, Montipora monasteriata, Turbinaria reniformis) were reared under the following six treatments for three weeks: 1) 400ppm CO2 and ambient temperature, 2) 400ppm CO2 and elevated temperature, 3) 650ppm CO2 and ambient temperature, 4) 650ppm CO2 and elevated temperature, 5) 800ppm CO2 and ambient temperature, 6) 800ppm CO2 and elevated temperature. Initial findings of photophysiological health (Fv/Fm), calcification rates (as measured by both buoyant weight and the total alkalinity methods), and energy reserves will be presented.

The Stress Corrosion Resistance and the Cryogenic Temperature Mechanical Behavior of 18-3 Mn (Nitronic 33) Stainless Steel Parent and Welded Material

NASA Technical Reports Server (NTRS)

Montano, J. W.

1976-01-01

The ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion results of 18-3 Mn (Nitronic 33)stainless steel, longitudinal and transverse, as received and as welded (TIG) material specimens manufactured from 0.063 inch thick sheet material, were described. The tensile test results indicate an increase in ultimate tensile and yield strengths with decreasing temperature. The elongation remained fairly constant to -200 F, but below that temperature the elongation decreased to less than 6.0% at liquid hydrogen temperature. The notched tensile strength (NTS) for the parent metal increased with decreasing temperature to liquid nitrogen temperature. Below -320 F the NTS decreased rapidly. The notched/unnotched (N/U) tensile ratio of the parent material specimens remained above 0.9 from ambient to -200 F, and decreased to approximately 0.65 and 0.62, respectively, for the longitudinal and transverse directions at liquid hydrogen temperature. After 180 days of testing, only those specimens exposed to the salt spray indicated pitting and some degradation of mechanical properties.

Effect of ambient temperature and relative humidity on interfacial temperature during early stages of drop evaporation.

PubMed

Fukatani, Yuki; Orejon, Daniel; Kita, Yutaku; Takata, Yasuyuki; Kim, Jungho; Sefiane, Khellil

2016-04-01

Understanding drop evaporation mechanisms is important for many industrial, biological, and other applications. Drops of organic solvents undergoing evaporation have been found to display distinct thermal patterns, which in turn depend on the physical properties of the liquid, the substrate, and ambient conditions. These patterns have been reported previously to be bulk patterns from the solid-liquid to the liquid-gas drop interface. In the present work the effect of ambient temperature and humidity during the first stage of evaporation, i.e., pinned contact line, is studied paying special attention to the thermal information retrieved at the liquid-gas interface through IR thermography. This is coupled with drop profile monitoring to experimentally investigate the effect of ambient temperature and relative humidity on the drop interfacial thermal patterns and the evaporation rate. Results indicate that self-generated thermal patterns are enhanced by an increase in ambient temperature and/or a decrease in humidity. The more active thermal patterns observed at high ambient temperatures are explained in light of a greater temperature difference generated between the apex and the edge of the drop due to greater evaporative cooling. On the other hand, the presence of water humidity in the atmosphere is found to decrease the temperature difference along the drop interface due to the heat of adsorption, absorption and/or that of condensation of water onto the ethanol drops. The control, i.e., enhancement or suppression, of these thermal patterns at the drop interface by means of ambient temperature and relative humidity is quantified and reported.

Radiant heat affects thermoregulation and energy expenditure during rewarming from torpor.

PubMed

Geiser, F; Drury, R L

2003-02-01

The high expenditure of energy required for endogenous rewarming is one of the widely perceived disadvantages of torpor. However, recent evidence demonstrates that passive rewarming either by the increase of ambient temperature or by basking in the sun appears to be common in heterothermic birds and mammals. As it is presently unknown how radiant heat affects energy expenditure during rewarming from torpor and little is known about how it affects normothermic thermoregulation, we quantified the effects of radiant heat on body temperature and metabolic rate of the small (body mass 25 g) marsupial Sminthopsis macroura in the laboratory. Normothermic resting individuals exposed to radiant heat were able to maintain metabolic rates near basal levels (at 0.91 ml O(2) g(-1) h(-1)) and a constant body temperature down to an ambient temperature of 12 degrees C. In contrast, metabolic rates of individuals without access to radiant heat were 4.5-times higher at an ambient temperature of 12 degrees C and body temperature fell with ambient temperature. During radiant heat-assisted passive rewarming from torpor, animals did not employ shivering but appeared to maximise uptake of radiant heat. Their metabolic rate increased only 3.2-times with a 15- degrees C rise of body temperature (Q(10)=2.2), as predicted by Q(10) effects. In contrast, during active rewarming shivering was intensive and metabolic rates showed an 11.6-times increase. Although body temperature showed a similar absolute change between the beginning and the end of the rewarming process, the overall energetic cost during active rewarming was 6.3-times greater than that during passive, radiant heat-assisted rewarming. Our study demonstrates that energetic models assuming active rewarming from torpor at low ambient temperatures can substantially over-estimate energetic costs. The low energy expenditure during passive arousal provides an alternative explanation as to why daily torpor is common in sunny regions and suggests that the prevalence of torpor in low latitudes may have been under-estimated in the past.

The influences of ambient temperature and crude protein levels on performance and serum biochemical parameters in broilers.

PubMed

Liu, Q W; Feng, J H; Chao, Z; Chen, Y; Wei, L M; Wang, F; Sun, R P; Zhang, M H

2016-04-01

This study was undertaken to investigate the effects of ambient temperature, crude protein levels and their interaction on performance and serum biochemical parameters of broiler chickens. A total of 216 Arbor Acre broiler chickens (108 males and 108 females) were used in a 2 × 3 factorial arrangement and randomly reared at two temperatures (normal temperature: 23 °C; daily cyclic high temperature: 28-32 °C) and fed on three diets with different crude protein levels (153.3, 183.3 or 213.3 g/kg, with constant essential amino acids) from 28 to 42 days of age. Daily cyclic high ambient temperature decreased final body weight, average daily weight gain, average daily feed intake and serum total protein contents (p < 0.001, p < 0.001, p < 0.001, p = 0.008 respectively), but increased feed/gain, mortality, respiratory rate, rectal temperature, serum uric acid contents and serum creatine kinase activity (p = 0.008, p = 0.003, p < 0.0001, p < 0.0001, p < 0.0001, p = 0.003 respectively), irrespective of crude protein levels. At the ambient temperature, reducing crude protein levels resulted in an increase in feed/gain (p < 0.001), but a decrease in serum total protein and uric acid contents. Only serum creatine kinase activity in broiler chickens was interacted by daily cyclic high ambient temperature and dietary crude protein levels (p = 0.003). These results indicated that daily cyclic high ambient temperature had a great effect on performance and serum biochemical parameters in broiler chickens, whereas dietary crude protein levels affected them partially. Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.

Brachial Artery Responses to Ambient Pollution, Temperature, and Humidity in People with Type 2 Diabetes: A Repeated-Measures Study

PubMed Central

Luttmann-Gibson, Heike; Horton, Edward S.; Cohen, Allison; Coull, Brent A.; Hoffmann, Barbara; Schwartz, Joel D.; Mittleman, Murray A.; Li, Yongsheng; Stone, Peter H.; de Souza, Celine; Lamparello, Brooke; Koutrakis, Petros; Gold, Diane R.

2014-01-01

Background: Extreme weather and air pollution are associated with increased cardiovascular risk in people with diabetes. Objectives: In a population with diabetes, we conducted a novel assessment of vascular brachial artery responses both to ambient pollution and to weather (temperature and water vapor pressure, a measure of humidity). Methods: Sixty-four 49- to 85-year-old Boston residents with type 2 diabetes completed up to five study visits (279 repeated measures). Brachial artery diameter (BAD) was measured by ultrasound before and after brachial artery occlusion [i.e., flow-mediated dilation (FMD)] and before and after nitroglycerin-mediated dilation (NMD). Ambient concentrations of fine particulate mass (PM2.5), black carbon (BC), organic carbon (OC), elemental carbon, particle number, and sulfate were measured at our monitoring site; ambient concentrations of carbon monoxide, nitrogen dioxide, and ozone were obtained from state monitors. Particle exposure in the home and during each trip to the clinic (home/trip exposure) was measured continuously and as a 5-day integrated sample. We used linear models with fixed effects for participants, adjusting for date, season, temperature, and water vapor pressure on the day of each visit, to estimate associations between our outcomes and interquartile range increases in exposure. Results: Baseline BAD was negatively associated with particle pollution, including home/trip–integrated BC (–0.02 mm; 95% CI: –0.04, –0.003, for a 0.28 μg/m3 increase in BC), OC (–0.08 mm; 95% CI: –0.14, –0.03, for a 1.61 μg/m3 increase) as well as PM2.5, 5-day average ambient PM2.5, and BC. BAD was positively associated with ambient temperature and water vapor pressure. However, exposures were not consistently associated with FMD or NMD. Conclusion: Brachial artery diameter, a predictor of cardiovascular risk, decreased in association with particle pollution and increased in association with ambient temperature in our study population of adults with type 2 diabetes. Citation: Zanobetti A, Luttmann-Gibson H, Horton ES, Cohen A, Coull BA, Hoffmann B, Schwartz JD, Mittleman MA, Li Y, Stone PH, de Souza C, Lamparello B, Koutrakis P, Gold DR. 2014. Brachial artery responses to ambient pollution, temperature, and humidity in people with type 2 diabetes: a repeated-measures study. Environ Health Perspect 122:242–248; http://dx.doi.org/10.1289/ehp.1206136 PMID:24398072

Temperature compensation analysis of liquid lens for variable-focus control

NASA Astrophysics Data System (ADS)

Chen, Shu-Jung; Tai, Tsai-Lin; Shen, Chih-Hsiung

2006-01-01

In this work, a fabrication and temperature compensation analysis and electrowetting for the liquid lenses is proposed. The unique capability of controlling the lens profile during the electrowetting fabrication processes is successfully demonstrated for different ambient temperature environment. For a lens fabricated on a hydrophobic Teflon layer, it is found that when the applied voltage is increased, the focal length increases, and the curvature decreases. One challenge for the liquid lens is operating temperature range. Due to the environment temperature change, the ability of controlling the lens profile is analyzed and measured. The description of change in contact angle corresponding to the variation of ambient temperature is derived. Based on this description, we firstly derive the control of voltage vs. temperature for a fixed dioptric power. The control of lens during a focusing action was studied by observation of the image formed by the light through the transparent bottom of ITO glass. Under several conditions of ambient temperature change, capability of controlling the lens profile for a fixed focus is successfully demonstrated by experiments.

Chemical states of surface oxygen during CO oxidation on Pt(1 1 0) surface revealed by ambient pressure XPS

DOE PAGES

Yu, Youngseok; Koh, Yoobin Esther; Lim, Hojoon; ...

2017-10-20

Here, the study of CO oxidation on Pt(110) surface is revisited using ambient pressure x-ray photoemission spectroscopy. When the surface temperature reaches the activation temperature for CO oxidation under elevated pressure conditions, both the α-phase of PtO 2 oxide and chemisorbed oxygen are formed simultaneously on the surface. Due to the exothermic nature of CO oxidation, the temperature of the Pt surface increases as CO oxidation takes place. As the CO/O 2 ratio increases, the production of CO 2 increases continuously and the surface temperature also increases. Interestingly, within the diffusion limited regions, the amount of surface oxide changes littlemore » while the chemisorbed oxygen is reduced.« less

Chemical states of surface oxygen during CO oxidation on Pt(1 1 0) surface revealed by ambient pressure XPS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Youngseok; Koh, Yoobin Esther; Lim, Hojoon

Here, the study of CO oxidation on Pt(110) surface is revisited using ambient pressure x-ray photoemission spectroscopy. When the surface temperature reaches the activation temperature for CO oxidation under elevated pressure conditions, both the α-phase of PtO 2 oxide and chemisorbed oxygen are formed simultaneously on the surface. Due to the exothermic nature of CO oxidation, the temperature of the Pt surface increases as CO oxidation takes place. As the CO/O 2 ratio increases, the production of CO 2 increases continuously and the surface temperature also increases. Interestingly, within the diffusion limited regions, the amount of surface oxide changes littlemore » while the chemisorbed oxygen is reduced.« less

Changes in nitrate and nitrite content of four vegetables during storage at refrigerated and ambient temperatures.

PubMed

Chung, J-C; Chou, S-S; Hwang, D-F

2004-04-01

The nitrate and nitrite contents of four kinds of vegetables (spinach, crown daisy, organic Chinese spinach and organic non-heading Chinese cabbage) in Taiwan were determined during storage at both refrigerated (5 +/- 1 degrees C) and ambient temperatures (22 +/- 1 degrees C) for 7 days. During storage at ambient temperature, nitrate levels in the vegetables dropped significantly from the third day while nitrite levels increased dramatically from the fourth day of storage. However, refrigerated storage did not lead to changes in nitrate and nitrite levels in the vegetables over 7 days.

Engineered Photorespiratory Bypass Pathways Improve Photosynthetic Efficiency and Growth as Temperature Increases

NASA Astrophysics Data System (ADS)

Cavanagh, A. P.; South, P. F.; Ort, D. R.; Bernacchi, C.

2017-12-01

In C3 plants grown under ambient [CO2] at 25°C, 23% of the fixed carbon dioxide is lost to photorespiration, the energy expensive metabolic pathway that recycles toxic compounds produced by Rubisco oxygenation reactions. Furthermore, rates of photorespiration increase with rising temperature, as higher temperatures favor increased Rubisco oxygenation. Modelling suggests that the absence of photorespiration could improve gross photosynthesis by 12-55% under projected climate conditions; however, this is difficult to measure empirically, as photorespiration interacts with several metabolic pathways and is an essential process for all C3 plants grown at ambient [O2]. Introduced biochemical bypasses to the native photorespiration pathway hold promise as a strategy to mitigate the impact of temperature on photorespiratory losses. We grew tobacco containing engineered pathways to bypass photorespiration under ambient and elevated temperatures (+5°C) in the field to determine if bypassing photorespiration could mitigate high temperature induced losses in growth and physiology. Our preliminary results show that engineered plants have a higher quantum efficiency under heated conditions than do non-engineered plants, resulting in up to 20% lower yield losses under heated conditions compared to non-engineered plants. These results support the theoretical modelling of temperature impacts on photorespiratory losses, and suggest the bypassing photorespiration could be an important strategy to increase crop yields.

Off-design performance of a chemical looping combustion (CLC) combined cycle: effects of ambient temperature

NASA Astrophysics Data System (ADS)

Chi, Jinling; Wang, Bo; Zhang, Shijie; Xiao, Yunhan

2010-02-01

The present work investigates the influence of ambient temperature on the steady-state off-design thermodynamic performance of a chemical looping combustion (CLC) combined cycle. A sensitivity analysis of the CLC reactor system was conducted, which shows that the parameters that influence the temperatures of the CLC reactors most are the flow rate and temperature of air entering the air reactor. For the ambient temperature variation, three off-design control strategies have been assumed and compared: 1) without any Inlet Guide Vane (IGV) control, 2) IGV control to maintain air reactor temperature and 3) IGV control to maintain constant fuel reactor temperature, aside from fuel flow rate adjusting. Results indicate that, compared with the conventional combined cycle, due to the requirement of pressure balance at outlet of the two CLC reactors, CLC combined cycle shows completely different off-design thermodynamic characteristics regardless of the control strategy adopted. For the first control strategy, temperatures of the two CLC reactors both rise obviously as ambient temperature increases. IGV control adopted by the second and the third strategy has the effect to maintain one of the two reactors' temperatures at design condition when ambient temperature is above design point. Compare with the second strategy, the third would induce more severe decrease of efficiency and output power of the CLC combined cycle.

A whole-tree chamber system for examining tree-level physiological responses of field-grown trees to environmental variation and climate change.

PubMed

Medhurst, Jane; Parsby, Jan; Linder, Sune; Wallin, Göran; Ceschia, Eric; Slaney, Michelle

2006-09-01

A whole-tree chamber (WTC) system was installed at Flakaliden in northern Sweden to examine the long-term physiological responses of field-grown 40-year-old Norway spruce trees [Picea abies (L.) Karst.] to climate change. The WTCs were designed as large cuvettes to allow the net tree-level CO(2) and water fluxes to be measured on a continuous basis. A total of 12 WTCs were used to impose combinations of atmospheric carbon dioxide concentration, [CO(2)], and air temperature treatments. The air inside the ambient and elevated [CO(2)] WTCs was maintained at 365 and 700 micromol mol(-1), respectively. The air temperature inside the ambient temperature WTCs tracked air temperature outside the WTCs. Elevated temperatures were altered on a monthly time-step and ranged between +2.8 and +5.6 degrees C above ambient temperature. The system allowed continuous, long-term measurement of whole-tree photosynthesis, night-time respiration and transpiration. The performance of the WTCs was assessed using winter and spring data sets. The ability of the WTC system to measure tree-level physiological responses is demonstrated. All WTCs displayed a high level of control over tracking of air temperatures. The set target of 365 micromol mol(-1) in the ambient [CO(2)] chambers was too low to be maintained during winter because of tree dormancy and the high natural increase in [CO(2)] over winter at high latitudes such as the Flakaliden site. Accurate control over [CO(2)] in the ambient [CO(2)] chambers was restored during the spring and the system maintained the elevated [CO(2)] target of 700 micromol mol(-1) for both measurement periods. Air water vapour deficit (VPD) was accurately tracked in ambient temperature WTCs. However, as water vapour pressure in all 12 WTCs was maintained at the level of non-chambered (reference) air, VPD of elevated temperature WTCs was increased.

Solid State Carbon Monoxide Sensor

NASA Technical Reports Server (NTRS)

Upchurch, Billy T. (Inventor); Wood, George M. (Inventor); Schryer, David R. (Inventor); Leighty, Bradley D. (Inventor); Oglesby, Donald M. (Inventor); Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); DAmbrosia, Christine M. (Inventor)

1999-01-01

A means for detecting carbon monoxide which utilizes an un-heated catalytic material to oxidize carbon monoxide at ambient temperatures. Because this reaction is exothermic, a thermistor in contact with the catalytic material is used as a sensing element to detect the heat evolved as carbon monoxide is oxidized to carbon dioxide at the catalyst surface, without any heaters or external heating elements for the ambient air or catalytic element material. Upon comparison to a reference thermistor, relative increases in the temperature of the sensing thermistor correspond positively with an increased concentration of carbon monoxide in the ambient medium and are thus used as an indicator of the presence of carbon monoxide.

Increased coronary heart disease and stroke hospitalisations from ambient temperatures in Ontario

PubMed Central

Bai, Li; Li, Qiongsi; Wang, Jun; Lavigne, Eric; Gasparrini, Antonio; Copes, Ray; Yagouti, Abderrahmane; Burnett, Richard T; Goldberg, Mark S; Cakmak, Sabit; Chen, Hong

2018-01-01

Objective To assess the associations between ambient temperatures and hospitalisations for coronary heart disease (CHD) and stroke. Methods Our study comprised all residents living in Ontario, Canada, 1996–2013. For each of 14 health regions, we fitted a distributed lag non-linear model to estimate the cold and heat effects on hospitalisations from CHD, acute myocardial infarction (AMI), stroke and ischaemic stroke, respectively. These effects were pooled using a multivariate meta-analysis. We computed attributable hospitalisations for cold and heat, defined as temperatures above and below the optimum temperature (corresponding to the temperature of minimum morbidity) and for moderate and extreme temperatures, defined using cut-offs at the 2.5th and 97.5th temperature percentiles. Results Between 1996 and 2013, we identified 1.4 million hospitalisations from CHD and 355 837 from stroke across Ontario. On cold days with temperature corresponding to the 1st percentile of temperature distribution, we found a 9% increase in daily hospitalisations for CHD (95% CI 1% to 16%), 29% increase for AMI (95% CI 15% to 45%) and 11% increase for stroke (95% CI 1% to 22%) relative to days with an optimal temperature. High temperatures (the 99th percentile) also increased CHD hospitalisations by 6% (95% CI 1% to 11%) relative to the optimal temperature. These estimates translate into 2.49% of CHD hospitalisations attributable to cold and 1.20% from heat. Additionally, 1.71% of stroke hospitalisations were attributable to cold. Importantly, moderate temperatures, rather than extreme temperatures, yielded the most of the cardiovascular burdens from temperatures. Conclusions Ambient temperatures, especially in moderate ranges, may be an important risk factor for cardiovascular-related hospitalisations. PMID:29101264

Ion transport with charge-protected and non-charge-protected cations in alcohol-based electrolytes using the compensated Arrhenius formalism. Part I: ionic conductivity and the static dielectric constant.

PubMed

Petrowsky, Matt; Fleshman, Allison; Frech, Roger

2012-05-17

The temperature dependence of ionic conductivity and the static dielectric constant is examined for 0.30 m TbaTf- or LiTf-1-alcohol solutions. Above ambient temperature, the conductivity increases with temperature to a greater extent in electrolytes whose salt has a charge-protected cation. Below ambient temperature, the dielectric constant changes only slightly with temperature in electrolytes whose salt has a cation that is not charge-protected. The compensated Arrhenius formalism is used to describe the temperature-dependent conductivity in terms of the contributions from both the exponential prefactor σo and Boltzmann factor exp(-Ea/RT). This analysis explains why the conductivity decreases with increasing temperature above 65 °C for the LiTf-dodecanol electrolyte. At higher temperatures, the decrease in the exponential prefactor is greater than the increase in the Boltzmann factor.

[Indoor simulation on dew formation on plant leaves].

PubMed

Gao, Zhi-Yong; Wang, You-Ke; Wei, Xin-Guang; Liu, Shou-Yang; He, Zi-Li; Zhou, Yu-Hong

2014-03-01

Dew forming on plant leaves through water condensation plays a significant ecological role in arid and semi-arid areas as an ignorable fraction of water resources. In this study, an artificial intelligent climate chamber and an automatic temperature-control system for leaves were implemented to regulate the ambient temperature, the leaf surface temperature and the leaf inclination for dew formation. The impact of leaf inclination, ambient temperature and dew point-leaf temperature depression on the rate and quantity of dew accumulation on leaf surface were analyzed. The results indicated that the accumulation rate and the maximum volume of dew on leaves decreased with increasing the leaf inclination while increased with the increment of dew point-leaf temperature depression, ambient temperature and relative humidity. Under the horizontal configuration, dew accumulated linearly on leaf surface over time until the maximum volume (0.80 mm) was reached. However, dew would fall down after reaching the maximum volume when the leaf inclination existed (45 degrees or 90 degrees), significantly slowing down the accumulative rate, and the zigzag pattern for the dynamic of dew accumulation appeared.

Effect of ambient temperature on human pain and temperature perception.

PubMed

Strigo, I A; Carli, F; Bushnell, M C

2000-03-01

Animal studies show reduced nociceptive responses to noxious heat stimuli and increases in endogenous beta-endorphin levels in cold environments, suggesting that human pain perception may be dependent on ambient temperature. However, studies of changes in local skin temperature on human pain perception have yielded variable results. This study examines the effect of both warm and cool ambient temperature on the perception of noxious and innocuous mechanical and thermal stimuli. Ten subjects (7 men and 3 women, aged 20-23 yr) used visual analog scales to rate the stimulus intensity, pain intensity, and unpleasantness of thermal (0-50 degrees C) and mechanical (1.2-28.9 g) stimuli applied on the volar forearm with a 1-cm2 contact thermode and von Frey filaments, respectively. Mean skin temperatures were measured throughout the experiment by infrared pyrometer. Each subject was tested in ambient temperatures of 15 degrees C (cool), 25 degrees C (neutral), and 35 degrees C (warm) on separate days, after a 30-min acclimation to the environment. Studies began in the morning after an 8-h fast. Mean skin temperature was altered by ambient temperature (cool room: 30.1 degrees C; neutral room: 33.4 degrees C; warm room: 34.5 degrees C; P < 0.0001). Ambient temperature affected both heat (44-50 degrees C) and cold (25-0 degrees C) perception (P < 0.01). Stimulus intensity ratings tended to be lower in the cool than in the neutral environment (P < 0.07) but were not different between the neutral and warm environments. Unpleasantness ratings revealed that cold stimuli were more unpleasant than hot stimuli in the cool room and that noxious heat stimuli were more unpleasant in a warm environment. Environmental temperature did not alter ratings of warm (37 and 40 degrees C) or mechanical stimuli. These results indicate that, in humans, a decrease in skin temperature following exposure to cool environments reduces thermal pain. Suppression of Adelta primary afferent cold fiber activity has been shown to increase cold pain produced by skin cooling. Our current findings may represent the reverse phenomenon, i.e., a reduction in thermal nociceptive transmission by the activation of Adelta cutaneous cold fibers.

Warming trumps CO2: future climate conditions suppress carbon fluxes in two dominant boreal tree species

NASA Astrophysics Data System (ADS)

Way, D.; Dusenge, M. E.; Madhavji, S.

2017-12-01

Increases in CO2 are expected to raise air temperatures in northern latitudes by up to 8 °C by the end of the century. Boreal forests in these regions play a large role in the global carbon cycle, and the responses of boreal tree species to climate drivers will thus have considerable impacts on the trajectory of future CO2 increases. We grew two dominant North American boreal tree species at a range of future climate conditions to assess how carbon fluxes were altered by high CO2 and warming. Black spruce (Picea mariana) and tamarack (Larix laricina) were grown from seed under either ambient (400 ppm) or elevated CO2 concentrations (750 ppm) and either ambient temperatures, moderate warming (ambient +4 °C), or extreme warming (ambient +8 °C) for six months. We measured temperature responses of net photosynthesis, maximum rates of Rubisco carboxylation (Vcmax) and electron transport (Jmax) and dark respiration to determine acclimation to the climate treatments. Overall, growth temperature had a strong effect on carbon fluxes, while there were no significant effects of growth CO2. In both species, the photosynthetic thermal optimum increased and maximum photosynthetic rates were reduced in warm-grown seedlings, but the strength of these changes varied between species. Vcmax and Jmax were also reduced in warm-grown seedlings, and this correlated with reductions in leaf N concentrations. Warming increased the activation energy for Vcmax and the thermal optimum for Jmax in both species. Respiration acclimated to elevated growth temperatures, but there were no treatment effects on the Q10 of respiration (the increase in respiration for a 10 °C increase in leaf temperature). Our results show that climate warming is likely to reduce carbon fluxes in these boreal conifers, and that photosynthetic parameters used to model photosynthesis in dynamic global vegetation models acclimate to increased temperatures, but show little response to elevated CO2.

The influence of season and ambient temperature on birth outcomes: a review of the epidemiological literature.

PubMed

Strand, Linn B; Barnett, Adrian G; Tong, Shilu

2011-04-01

Seasonal patterns of birth outcomes, such as low birth weight, preterm birth and stillbirth, have been found around the world. As a result, there has been an increasing interest in evaluating short-term exposure to ambient temperature as a determinant of adverse birth outcomes. This paper reviews the epidemiological evidence on seasonality of birth outcomes and the impact of prenatal exposure to ambient temperature on birth outcomes. We identified 20 studies that investigated seasonality of birth outcomes, and reported statistically significant seasonal patterns. Most of the studies found peaks of preterm birth, stillbirth and low birth weight in winter, summer or both, which indicates the extremes of temperature may be an important determinant of poor birth outcomes. We identified 13 studies that investigated the influence of exposure to ambient temperature on birth weight and preterm birth (none examined stillbirth). The evidence for an adverse effect of high temperatures was stronger for birth weight than for preterm birth. More research is needed to clarify whether high temperatures have a causal effect on fetal health. Copyright © 2011 Elsevier Inc. All rights reserved.

Developmental responses of bread wheat to changes in ambient temperature following deletion of a locus that includes FLOWERING LOCUS T1.

PubMed

Dixon, Laura E; Farré, Alba; Finnegan, E Jean; Orford, Simon; Griffiths, Simon; Boden, Scott A

2018-01-04

FLOWERING LOCUS T (FT) is a central integrator of environmental signals that regulates the timing of vegetative to reproductive transition in flowering plants. In model plants, these environmental signals have been shown to include photoperiod, vernalization, and ambient temperature pathways, and in crop species, the integration of the ambient temperature pathway remains less well understood. In hexaploid wheat, at least 5 FT-like genes have been identified, each with a copy on the A, B, and D genomes. Here, we report the characterization of FT-B1 through analysis of FT-B1 null and overexpression genotypes under different ambient temperature conditions. This analysis has identified that the FT-B1 alleles perform differently under diverse environmental conditions; most notably, the FT-B1 null produces an increase in spikelet and tiller number when grown at lower temperature conditions. Additionally, absence of FT-B1 facilitates more rapid germination under both light and dark conditions. These results provide an opportunity to understand the FT-dependent pathways that underpin key responses of wheat development to changes in ambient temperature. This is particularly important for wheat, for which development and grain productivity are sensitive to changes in temperature. © 2018 The Authors Plant, Cell & Environment Published by John Wiley & Sons Ltd.

Ambient temperature and activation of implantable cardioverter defibrillators

NASA Astrophysics Data System (ADS)

McGuinn, L.; Hajat, S.; Wilkinson, P.; Armstrong, B.; Anderson, H. R.; Monk, V.; Harrison, R.

2013-09-01

The degree to which weather influences the occurrence of serious cardiac arrhythmias is not fully understood. To investigate, we studied the timing of activation of implanted cardiac defibrillators (ICDs) in relation to daily outdoor temperatures using a fixed stratum case-crossover approach. All patients attending ICD clinics in London between 1995 and 2003 were recruited onto the study. Temperature exposure for each ICD patient was determined by linking each patient's postcode of residence to their nearest temperature monitoring station in London and the South of England. There were 5,038 activations during the study period. Graphical inspection of ICD activation against temperature suggested increased risk at lower but not higher temperatures. For every 1 °C decrease in ambient temperature, risk of ventricular arrhythmias up to 7 days later increased by 1.2 % (95 % CI -0.6 %, 2.9 %). In threshold models, risk of ventricular arrhythmias increased by 11.2 % (0.5 %, 23.1 %) for every 1° decrease in temperature below 2 °C. Patients over the age of 65 exhibited the highest risk. This large study suggests an inverse relationship between ambient outdoor temperature and risk of ventricular arrhythmias. The highest risk was found for patients over the age of 65. This provides evidence about a mechanism for some cases of low-temperature cardiac death, and suggests a possible strategy for reducing risk among selected cardiac patients by encouraging behaviour modification to minimise cold exposure.

Development of Apparatus for Microgravity Experiments on Evaporation and Combustion of Palm Methyl Ester Droplet in High-Pressure Environments

NASA Astrophysics Data System (ADS)

Suzuki, Masato; Nomura, Hiroshi; Hashimoto, Nozomu

New apparatus for microgravity experiments was developed in order to obtain fundamental data of single droplet evaporation and combustion of palm methyl ester (PME) for understanding PME spray combustion in internal combustion engines. n-hexadecane droplet combustion and evaporation experiments were also performed to obtain single-component fuel data. Combustion experiments were performed at atmospheric pressure and room temperature. For droplet evaporation experiments, ambient temperature and pressure were varied from 473 to 873 K and 0.10 to 4.0 MPa, respectively. Microgravity conditions were employed for evaporation experiments to prevent natural convection. Droplet diameter history of a burning PME droplet is similar to that of n-hexadecane. Droplet diameter history of an evaporating PME droplet is different from that of n-hexadecane at low ambient temperatures. In the latest stage of PME droplet evaporation, temporal evaporation constant decreases remarkably. At ambient temperatures sufficiently above the boiling temperature of PME components, droplet diameter history of PME and n-hexadecane are similar to each other. Corrected evaporation lifetime τ of PME at 873 K as a function of ambient pressure was obtained at normal and microgravity. At normal gravity, τ monotonically decreases with ambient pressure. On the other hand, at microgravity, τ increases with ambient pressure, and then decreases.

Ambient air pollution, temperature and out-of-hospital coronary deaths in Shanghai, China.

PubMed

Dai, Jinping; Chen, Renjie; Meng, Xia; Yang, Changyuan; Zhao, Zhuohui; Kan, Haidong

2015-08-01

Few studies have evaluated the effects of ambient air pollution and temperature in triggering out-of-hospital coronary deaths (OHCDs) in China. We evaluated the associations of air pollution and temperature with daily OHCDs in Shanghai, China from 2006 to 2011. We applied an over-dispersed generalized additive model and a distributed lag nonlinear model to analyze the effects of air pollution and temperature, respectively. A 10 μg/m(3) increase in the present-day PM10, PM2.5, SO2, NO2 and CO were associated with increases in OHCD mortality of 0.49%, 0.68%, 0.88%, 1.60% and 0.08%, respectively. A 1 °C decrease below the minimum-mortality temperature corresponded to a 3.81% increase in OHCD mortality on lags days 0-21, and a 1 °C increase above minimum-mortality temperature corresponded to a 4.61% increase over lag days 0-3. No effects were found for in-hospital coronary deaths. This analysis suggests that air pollution, low temperature and high temperature may increase the risk of OHCDs. Copyright © 2015 Elsevier Ltd. All rights reserved.

High-Temperature Electronics: A Role for Wide Bandgap Semiconductors?

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Okojie, Robert S.; Chen, Liang-Yu

2002-01-01

It is increasingly recognized that semiconductor based electronics that can function at ambient temperatures higher than 150 C without external cooling could greatly benefit a variety of important applications, especially-in the automotive, aerospace, and energy production industries. The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in low-power transistor applications until the ambient temperature exceeds approximately 300 C, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog very large scale integrated circuits in this temperature range. However, practical operation of silicon power devices at ambient temperatures above 200 C appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and high-power operation will necessarily be realized using wide bandgap devices, once the technology for realizing these devices become sufficiently developed that they become widely available. Technological challenges impeding the realization of beneficial wide bandgap high ambient temperature electronics, including material growth, contacts, and packaging, are briefly discussed.

Climate change affects low trophic level marine consumers: warming decreases copepod size and abundance.

PubMed

Garzke, Jessica; Ismar, Stefanie M H; Sommer, Ulrich

2015-03-01

Concern about climate change has re-ignited interest in universal ecological responses to temperature variations: (1) biogeographical shifts, (2) phenology changes, and (3) size shifts. In this study we used copepods as model organisms to study size responses to temperature because of their central role in the pelagic food web and because of the ontogenetic length constancy between molts, which facilitates the definition of size of distinct developmental stages. In order to test the expected temperature-induced shifts towards smaller body size and lower abundances under warming conditions, a mesocosm experiment using plankton from the Baltic Sea at three temperature levels (ambient, ambient +4 °C, ambient -4 °C) was performed in summer 2010. Overall copepod and copepodit abundances, copepod size at all life stages, and adult copepod size in particular, showed significant temperature effects. As expected, zooplankton peak abundance was lower in warm than in ambient treatments. Copepod size-at-immature stage significantly increased in cold treatments, while adult size significantly decreased in warm treatments.

High ambient temperature and mortality: a review of epidemiologic studies from 2001 to 2008

PubMed Central

2009-01-01

Background This review examines recent evidence on mortality from elevated ambient temperature for studies published from January 2001 to December 2008. Methods PubMed was used to search for the following keywords: temperature, apparent temperature, heat, heat index, and mortality. The search was limited to the English language and epidemiologic studies. Studies that reported mortality counts or excess deaths following heat waves were excluded so that the focus remained on general ambient temperature and mortality in a variety of locations. Studies focusing on cold temperature effects were also excluded. Results Thirty-six total studies were presented in three tables: 1) elevated ambient temperature and mortality; 2) air pollutants as confounders and/or effect modifiers of the elevated ambient temperature and mortality association; and 3) vulnerable subgroups of the elevated ambient temperature-mortality association. The evidence suggests that particulate matter with less than 10 um in aerodynamic diameter and ozone may confound the association, while ozone was an effect modifier in the warmer months in some locations. Nonetheless, the independent effect of temperature and mortality was withheld. Elevated temperature was associated with increased risk for those dying from cardiovascular, respiratory, cerebrovascular, and some specific cardiovascular diseases, such as ischemic heart disease, congestive heart failure, and myocardial infarction. Vulnerable subgroups also included: Black racial/ethnic group, women, those with lower socioeconomic status, and several age groups, particularly the elderly over 65 years of age as well as infants and young children. Conclusion Many of these outcomes and vulnerable subgroups have only been identified in recent studies and varied by location and study population. Thus, region-specific policies, especially in urban areas, are vital to the mitigation of heat-related deaths. PMID:19758453

Insect eggs protected from high temperatures by limited homeothermy of plant leaves.

PubMed

Potter, Kristen; Davidowitz, Goggy; Woods, H Arthur

2009-11-01

Virtually all aspects of insect biology are affected by body temperature, and many taxa have evolved sophisticated temperature-control mechanisms. All insects, however, begin life as eggs and lack the ability to thermoregulate. Eggs laid on leaves experience a thermal environment, and thus a body temperature, that is strongly influenced by the leaves themselves. Because plants can maintain leaf temperatures that differ from ambient, e.g. by evapotranspiration, plant hosts may protect eggs from extreme ambient temperatures. We examined the degree to which leaves buffer ambient thermal variation and whether that buffering benefits leaf-associated insect eggs. In particular, we: (1) measured temperature variation at oviposition sites in the field, (2) manipulated temperatures in the laboratory to determine the effect of different thermal conditions on embryo development time and survival, and (3) tested embryonic metabolic rates over increasing temperatures. Our results show that Datura wrightii leaves buffer Manduca sexta eggs from fatally high ambient temperatures in the southwestern USA. Moreover, small differences in temperature profiles among leaves can cause large variation in egg metabolic rate and development time. Specifically, large leaves were hotter than small leaves during the day, reaching temperatures that are stressfully high for eggs. This study provides the first mechanistic demonstration of how this type of leaf-constructed thermal refuge interacts with egg physiology.

Evaporative water loss, relative water economy and evaporative partitioning of a heterothermic marsupial, the monito del monte (Dromiciops gliroides).

PubMed

Withers, Philip C; Cooper, Christine E; Nespolo, Roberto F

2012-08-15

We examine here evaporative water loss, economy and partitioning at ambient temperatures from 14 to 33°C for the monito del monte (Dromiciops gliroides), a microbiotheriid marsupial found only in temperate rainforests of Chile. The monito's standard evaporative water loss (2.58 mg g(-1) h(-1) at 30°C) was typical for a marsupial of its body mass and phylogenetic position. Evaporative water loss was independent of air temperature below thermoneutrality, but enhanced evaporative water loss and hyperthermia were the primary thermal responses above the thermoneutral zone. Non-invasive partitioning of total evaporative water loss indicated that respiratory loss accounted for 59-77% of the total, with no change in respiratory loss with ambient temperature, but a small change in cutaneous loss below thermoneutrality and an increase in cutaneous loss in and above thermoneutrality. Relative water economy (metabolic water production/evaporative water loss) increased at low ambient temperatures, with a point of relative water economy of 15.4°C. Thermolability had little effect on relative water economy, but conferred substantial energy savings at low ambient temperatures. Torpor reduced total evaporative water loss to as little as 21% of normothermic values, but relative water economy during torpor was poor even at low ambient temperatures because of the relatively greater reduction in metabolic water production than in evaporative water loss. The poor water economy of the monito during torpor suggests that negative water balance may explain why hibernators periodically arouse to normothermia, to obtain water by drinking or via an improved water economy.

Ambient Temperature and Stroke Occurrence: A Systematic Review and Meta-Analysis.

PubMed

Wang, Xia; Cao, Yongjun; Hong, Daqing; Zheng, Danni; Richtering, Sarah; Sandset, Else Charlotte; Leong, Tzen Hugh; Arima, Hisatomi; Islam, Shariful; Salam, Abdul; Anderson, Craig; Robinson, Thompson; Hackett, Maree L

2016-07-12

Biologically plausible associations exist between climatic conditions and stroke risk, but study results are inconsistent. We aimed to summarize current evidence on ambient temperature and overall stroke occurrence, and by age, sex, and variation of temperature. We performed a systematic literature search across MEDLINE, Embase, PsycINFO, CINAHL, Web of Science, and GEOBASE, from inception to 16 October 2015 to identify all population-based observational studies. Where possible, data were pooled for meta-analysis with Odds ratios (OR) and corresponding 95% confidence intervals (CI) by means of the random effects meta-analysis. We included 21 studies with a total of 476,511 patients. The data were varied as indicated by significant heterogeneity across studies for both ischemic stroke (IS) and intracerebral hemorrhage (ICH). Pooled OR (95% CI) in every 1 degree Celsius increase in ambient temperature was significant for ICH 0.97 (0.94-1.00), but not for IS 1.00 (0.99-1.01) and subarachnoid hemorrhage (SAH) 1.00 (0.98-1.01). Meta-analysis was not possible for the pre-specified subgroup analyses by age, sex, and variation of temperature. Change in temperature over the previous 24 h appeared to be more important than absolute temperature in relation to the risk of stroke, especially in relation to the risk of ICH. Older age appeared to increase vulnerability to low temperature for both IS and ICH. To conclude, this review shows that lower mean ambient temperature is significantly associated with the risk of ICH, but not with IS and SAH. Larger temperature changes were associated with higher stroke rates in the elderly.

Low ambient temperature elevates plasma triiodothyronine concentrations while reducing digesta mean retention time and methane yield in sheep.

PubMed

Barnett, M C; McFarlane, J R; Hegarty, R S

2015-06-01

Ruminant methane yield (MY) is positively correlated with mean retention time (MRT) of digesta. The hormone triiodothyronine (T3 ), which is negatively correlated with ambient temperature, is known to influence MRT. It was hypothesised that exposing sheep to low ambient temperatures would increase plasma T3 concentration and decrease MRT of digesta within the rumen of sheep, resulting in a reduction of MY. To test this hypothesis, six Merino sheep were exposed to two different ambient temperatures (cold treatment, 9 ± 1 °C; warm control 26 ± 1 °C). The effects on MY, digesta MRT, plasma T3 concentration, CO2 production, DM intake, DM digestibility, change in body weight (BW), rumen volatile fatty acid (VFA) concentrations, estimated microbial protein output, protozoa abundance, wool growth, water intake, urine output and rectal temperature were studied. Cold treatment resulted in a reduction in MY (p < 0.01); digesta MRT in rumen (p < 0.01), hindgut (p = 0.01) and total digestive tract (p < 0.01); protozoa abundance (p < 0.05); and water intake (p < 0.001). Exposure to cold temperature increased plasma T3 concentration (p < 0.05), CO2 production (p = 0.01), total VFA concentrations (p = 0.03) and estimated microbial output from the rumen (p = 0.03). The rate of wool growth increased (p < 0.01) due to cold treatment, but DM intake, DM digestibility and BW change were not affected. The results suggest that exposure of sheep to cold ambient temperatures reduces digesta retention time in the gastrointestinal tract, leading to a reduction in enteric methane yield. Further research is warranted to determine whether T3 could be used as an indirect selection tool for genetic selection of low enteric methane-producing ruminants. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

The Burden of COPD Morbidity Attributable to the Interaction between Ambient Air Pollution and Temperature in Chengdu, China.

PubMed

Qiu, Hang; Tan, Kun; Long, Feiyu; Wang, Liya; Yu, Haiyan; Deng, Ren; Long, Hu; Zhang, Yanlong; Pan, Jingping

2018-03-11

Evidence on the burden of chronic obstructive pulmonary disease (COPD) morbidity attributable to the interaction between ambient air pollution and temperature has been limited. This study aimed to examine the modification effect of temperature on the association of ambient air pollutants (including particulate matter (PM) with aerodynamic diameter <10 μm (PM 10 ) and <2.5 μm (PM 2.5 ), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), carbon monoxide (CO) and ozone (O₃)) with risk of hospital admissions (HAs) for COPD, as well as the associated morbidity burden in urban areas of Chengdu, China, from 2015 to 2016. Based on the generalized additive model (GAM) with quasi-Poisson link, bivariate response surface model and stratification parametric model were developed to investigate the potential interactions between ambient air pollution and temperature on COPD HAs. We found consistent interactions between ambient air pollutants (PM 2.5 , PM 10 and SO₂) and low temperature on COPD HAs, demonstrated by the stronger associations between ambient air pollutants and COPD HAs at low temperatures than at moderate temperatures. Subgroup analyses showed that the elderly (≥80 years) and males were more vulnerable to this interaction. The joint effect of PM and low temperature had the greatest impact on COPD morbidity burden. Using WHO air quality guidelines as reference concentration, about 17.30% (95% CI: 12.39%, 22.19%) and 14.72% (95% CI: 10.38%, 19.06%) of COPD HAs were attributable to PM 2.5 and PM 10 exposures on low temperature days, respectively. Our findings suggested that low temperature significantly enhanced the effects of PM and SO₂ on COPD HAs in urban Chengdu, resulting in increased morbidity burden. This evidence has important implications for developing interventions to reduce the risk effect of COPD morbidity.

Effects of ambient temperature and early open-field response on the behaviour, feed intake and growth of fast- and slow-growing broiler strains.

PubMed

Nielsen, B L

2012-09-01

Increased activity improves broiler leg health, but also increases the heat production of the bird. This experiment investigated the effects of early open-field activity and ambient temperature on the growth and feed intake of two strains of broiler chickens. On the basis of the level of activity in an open-field test on day 3 after hatching, fast-growing Ross 208 and slow-growing i657 chickens were allocated on day 13 to one of the 48 groups. Each group included either six active or six passive birds from each strain and the groups were housed in floor-pens littered with wood chips and fitted with two heat lamps. Each group was fed ad libitum and subjected to one of the three temperature treatments: two (HH; 26°C), one (HC; 16°C to 26°C) or no (CC; 16°C) heat lamps turned on. Production and behavioural data were collected every 2 weeks until day 57. For both strains, early open-field activity had no significant effects on their subsequent behaviour or on any of the production parameters measured, and overall, the slow-growing strain was more active than the fast-growing strain. Ambient temperature had significant effects on production measures for i657 broilers, with CC chickens eating and weighing more, and with a less efficient feed conversion than HH chickens, with HC birds intermediate. A similar effect was found for Ross 208 only for feed intake from 27 to 41 days of age. Ross 208 chickens distributed themselves in the pen with a preference for cooler areas in the hottest ambient temperature treatments. In contrast, the behaviour of the slow-growing strain appeared to be relatively unaffected by the ambient temperature. In conclusion, fast-growing broilers use behavioural changes when trying to adapt to warm environments, whereas slow-growing broilers use metabolic changes to adapt to cooler ambient temperatures.

Temperature dependence of electrical properties of gallium-nitride bulk single crystals doped with Mg and their evolution with annealing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Litwin-Staszewska, E.; Suski, T.; Piotrzkowski, R.

Comprehensive studies of the electrical properties of Mg-doped bulk GaN crystals, grown by high-pressure synthesis, were performed as a function of temperature up to 750{degree}C. Annealing of the samples in nitrogen ambient modifies qualitatively their resistivity values {rho} and the {rho}(T) variation. It was found that our material is characterized by a high concentration of oxygen-related donors and that the charge transport in the studied samples is determined by two types of states, one of shallow character (Mg-related state, E{sub A}{approximately}0.15eV), and the second one much more deep, E{sub 2}{approximately}0.95eV (above the valence band). Depending on the effective concentration ofmore » either states, different resistivities {rho} can be observed: lower resistivity ({rho}{lt}10{sup 4}{Omega}cm at ambient temperature) in samples with dominant E{sub A} states and very high resistivity ({rho}{gt}10{sup 6}{Omega}cm at ambient temperature) in samples with dominant E{sub 2} states. For the first type of samples, annealing at T{sub ann}{lt}500{degree}C leads to a decrease of their resistivity and is associated with an increase of the effective concentration of the shallow Mg acceptors. Annealing of both types of samples at temperatures between 600 and 750{degree}C leads to an increase of the deep state concentration. The presence of hydrogen ambient during annealing of the low-resistivity samples strongly influences their properties. The increase of the sample resistivity and an appearance of a local vibrational mode of hydrogen at 3125 cm{minus}1 were observed. These effects can be removed by annealing in hydrogen-free ambient. {copyright} 2001 American Institute of Physics.« less

Structural and Dynamical Properties of Alkaline Earth Metal Halides in Supercritical Water: Effect of Ion Size and Concentration.

PubMed

Keshri, Sonanki; Tembe, B L

2017-11-22

Constant temperature-constant pressure molecular dynamics simulations have been performed for aqueous alkaline earth metal chloride [M 2+ -Cl - (M = Mg, Ca, Sr, and Ba)] solutions over a wide range of concentrations (0.27-5.55 m) in supercritical (SC) and ambient conditions to investigate their structural and dynamical properties. A strong influence of the salt concentration is observed on the ion-ion pair correlation functions in both ambient and SC conditions. In SC conditions, significant clustering is observed in the 0.27 m solution, whereas the reverse situation is observed at room temperature and this is also supported by the residence times of the clusters. The concentration and ion size (cation size) seem to have opposite effects on the average number of hydrogen bonds. The simulation results show that the self-diffusion coefficients of water, cations, and the chloride ion increase with increasing temperature, whereas they decrease with increasing salt concentration. The cluster size distribution shows a strong density dependence in both ambient and SC conditions. In SC conditions, cluster sizes display a near-Gaussian distribution, whereas the distribution decays monotonically in ambient conditions.

Ambient temperature affects postnatal litter size reduction in golden hamsters.

PubMed

Ohrnberger, Sarah A; Monclús, Raquel; Rödel, Heiko G; Valencak, Teresa G

2016-01-01

To better understand how different ambient temperatures during lactation affect survival of young, we studied patterns of losses of pups in golden hamsters ( Mesocricetus auratus ) at different ambient temperatures in the laboratory, mimicking temperature conditions in natural habitats. Golden hamsters produce large litters of more than 10 young but are also known to wean fewer pups at the end of lactation than they give birth to. We wanted to know whether temperature affects litter size reductions and whether the underlying causes of pup loss were related to maternal food (gross energy) intake and reproductive performance, such as litter growth. For that, we exposed lactating females to three different ambient temperatures and investigated associations with losses of offspring between birth and weaning. Overall, around one third of pups per litter disappeared, obviously consumed by the mother. Such litter size reductions were greatest at 30 °C, in particular during the intermediate postnatal period around peak lactation. Furthermore, litter size reductions were generally higher in larger litters. Maternal gross energy intake was highest at 5 °C suggesting that mothers were not limited by milk production and might have been able to raise a higher number of pups until weaning. This was further supported by the fact that the daily increases in litter mass as well as in the individual pup body masses, a proxy of mother's lactational performance, were lower at higher ambient temperatures. We suggest that ambient temperatures around the thermoneutral zone and beyond are preventing golden hamster females from producing milk at sufficient rates. Around two thirds of the pups per litter disappeared at high temperature conditions, and their early growth rates were significantly lower than at lower ambient temperatures. It is possible that these losses are due to an intrinsic physiological limitation (imposed by heat dissipation) compromising maternal energy intake and milk production.

Ambient temperature enhanced acute cardiovascular-respiratory mortality effects of PM2.5 in Beijing, China.

PubMed

Li, Yi; Ma, Zhiqiang; Zheng, Canjun; Shang, Yu

2015-12-01

Studies have shown that temperature could modify the effect of ambient fine particles on mortality risk. In assessing air pollution effects, temperature is usually considered as a confounder. However, ambient temperature can alter people's physiological response to air pollution and might "modify" the impact of air pollution on health outcomes. This study investigated the interaction between daily PM2.5 and daily mean temperature in Beijing, China, using data for the period 2005-2009. Bivariate PM2.5-temperature response surfaces and temperature-stratified generalized additive model (GAM) were applied to study the effect of PM2.5 on cardiovascular, respiratory mortality, and total non-accidental mortality across different temperature levels. We found that low temperature could significantly enhance the effect of PM2.5 on cardiovascular mortality. For an increase of 10 μg/m(3) in PM2.5 concentration in the lowest temperature range (-9.7∼2.6 °C), the relative risk (RR) of cardiovascular mortality increased 1.27 % (95 % CI 0.38∼2.17 %), which was higher than that of the whole temperature range (0.59 %, 95 % CI 0.22-1.16 %). The largest effect of PM2.5 on respiratory mortality appeared in the high temperature range. For an increase of 10 μg/m(3) in PM2.5 concentration, RR of respiratory mortality increased 1.70 % (95 % CI 0.92∼3.33 %) in the highest level (23.50∼31.80 °C). For the total non-accidental mortality, significant associations appeared only in low temperature levels (-9.7∼2.6 °C): for an increase of 10 μg/m(3) in current day PM2.5 concentration, RR increased 1.27 % (95 % CI 0.46∼2.00 %) in the lowest temperature level. No lag effect was observed. The results suggest that in air pollution mortality time series studies, the possibility of an interaction between air pollution and temperature should be considered.

Ambient temperature enhanced acute cardiovascular-respiratory mortality effects of PM2.5 in Beijing, China

NASA Astrophysics Data System (ADS)

Li, Yi; Ma, Zhiqiang; Zheng, Canjun; Shang, Yu

2015-12-01

Studies have shown that temperature could modify the effect of ambient fine particles on mortality risk. In assessing air pollution effects, temperature is usually considered as a confounder. However, ambient temperature can alter people's physiological response to air pollution and might "modify" the impact of air pollution on health outcomes. This study investigated the interaction between daily PM2.5 and daily mean temperature in Beijing, China, using data for the period 2005-2009. Bivariate PM2.5-temperature response surfaces and temperature-stratified generalized additive model (GAM) were applied to study the effect of PM2.5 on cardiovascular, respiratory mortality, and total non-accidental mortality across different temperature levels. We found that low temperature could significantly enhance the effect of PM2.5 on cardiovascular mortality. For an increase of 10 μg/m3 in PM2.5 concentration in the lowest temperature range (-9.7˜2.6 °C), the relative risk (RR) of cardiovascular mortality increased 1.27 % (95 % CI 0.38˜2.17 %), which was higher than that of the whole temperature range (0.59 %, 95 % CI 0.22-1.16 %). The largest effect of PM2.5 on respiratory mortality appeared in the high temperature range. For an increase of 10 μg/m3 in PM2.5 concentration, RR of respiratory mortality increased 1.70 % (95 % CI 0.92˜3.33 %) in the highest level (23.50˜31.80 °C). For the total non-accidental mortality, significant associations appeared only in low temperature levels (-9.7˜2.6 °C): for an increase of 10 μg/m3 in current day PM2.5 concentration, RR increased 1.27 % (95 % CI 0.46˜2.00 %) in the lowest temperature level. No lag effect was observed. The results suggest that in air pollution mortality time series studies, the possibility of an interaction between air pollution and temperature should be considered.

High ambient temperature increases 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy")-induced Fos expression in a region-specific manner.

PubMed

Hargreaves, G A; Hunt, G E; Cornish, J L; McGregor, I S

2007-03-16

3,4-Methylenedioxymethamphetamine (MDMA, "Ecstasy") is a popular drug that is often taken under hot conditions at dance clubs. High ambient temperature increases MDMA-induced hyperthermia and recent studies suggest that high temperatures may also enhance the rewarding and prosocial effects of MDMA in rats. The present study investigated whether ambient temperature influences MDMA-induced expression of Fos, a marker of neural activation. Male Wistar rats received either MDMA (10 mg/kg i.p.) or saline, and were placed in test chambers for 2 h at either 19 or 30 degrees C. MDMA caused significant hyperthermia at 30 degrees C and a modest hypothermia at 19 degrees C. The 30 degrees C ambient temperature had little effect on Fos expression in vehicle-treated rats. However MDMA-induced Fos expression was augmented in 15 of 30 brain regions at the high temperature. These regions included (1) sites associated with thermoregulation such as the median preoptic nucleus, dorsomedial hypothalamus and raphe pallidus, (2) the supraoptic nucleus, a region important for osmoregulation and a key mediator of oxytocin and vasopressin release, (3) the medial and central nuclei of the amygdala, important in the regulation of social and emotional behaviors, and (4) the shell of the nucleus accumbens and (anterior) ventral tegmental area, regions associated with the reinforcing effects of MDMA. MDMA-induced Fos expression was unaffected by ambient temperature at many other sites, and was diminished at high temperature at one site (the islands of Calleja), suggesting that the effect of temperature on MDMA-induced Fos expression was not a general pharmacokinetic effect. Overall, these results indicate that high temperatures accentuate key neural effects of MDMA and this may help explain the widespread use of the drug under hot conditions at dance parties as well as the more hazardous nature of MDMA taken under such conditions.

The impact of heat stress on operative performance and cognitive function during simulated laparoscopic operative tasks.

PubMed

Berg, Regan J; Inaba, Kenji; Sullivan, Maura; Okoye, Obi; Siboni, Stefano; Minneti, Michael; Teixeira, Pedro G; Demetriades, Demetrios

2015-01-01

Increasing ambient temperature to prevent intraoperative patient hypothermia remains widely advocated despite unconvincing evidence of efficacy. Heat stress is associated with decreased cognitive and psychomotor performance across multiple tasks but remains unexamined in an operative context. We assessed the impact of increased ambient temperature on laparoscopic operative performance and surgeon cognitive stress. Forty-two performance measures were obtained from 21 surgery trainees participating in the counter-balanced, within-subjects study protocol. Operative performance was evaluated with adaptations of the validated, peg-transfer, and intracorporeal knot-tying tasks from the Fundamentals of Laparoscopic Surgery program. Participants trained to proficiency before enrollment. Task performance was measured at two ambient temperatures, 19 and 26°C (66 and 79°F). Participants were randomly counterbalanced to initial hot or cold exposure before crossing over to the alternate environment. Cognitive stress was measured using the validated Surgical Task Load Index (SURG-TLX). No differences in performance of the peg-transfer and intracorporeal knot-tying tasks were seen across ambient conditions. Assessed via use of the six bipolar scales of the SURG-TLX, we found differences in task workload between the hot and cold conditions in the areas of physical demands (hot 10 [3-12], cold 5 [2.5-9], P = .013) and distractions (hot 8 [3.5-15.5], cold 3 [1.5-5.5], P = .001). Participant perception of distraction remained greater in the hot condition on full scoring of the SURG-TLX. Increasing ambient temperature to levels advocated for prevention of intraoperative hypothermia does not greatly decrease technical performance in short operative tasks. Surgeons, however, do report increased perceptions of distraction and physical demand. The impact of these findings on performance and outcomes during longer operative procedures remains unclear. Copyright © 2015 Elsevier Inc. All rights reserved.

Environmental physiology of a small marsupial inhabiting arid floodplains.

PubMed

Warnecke, L; Cooper, C E; Geiser, F; Withers, P C

2010-09-01

Giles' planigale (Planigale gilesi) is among the smallest extant marsupials and inhabits deep soil cracks in arid floodplains. We examined whether its physiology shows specific adaptations to its extreme habitat. Metabolic rate, body temperature, evaporative water loss and thermal conductance were measured for eight planigales (average mass 9 g) exposed to four different ambient temperatures ranging from 10 degrees C to 32 degrees C. Water economy and respiratory variables were measured for the first time in this species. All of these standard physiological variables conformed to allometrically-predicted values for a marsupial. All variables were significantly affected by ambient temperature, except tidal volume and dry thermal conductance. Metabolic rate increased substantially at low ambient temperatures, as required to maintain a relatively constant body temperature of about 32-34 degrees C. This increased oxygen demand was accommodated by increased ventilation rather than increased oxygen extraction. Planigales had a comparatively high point of relative water economy of 19.1 degrees C, consistent with their small body size and arid habitat. Torpor reduced energy expenditure by 79% and evaporative water loss by 62%. Our study suggests that torpor use, along with behavioural adaptations, suffice for P. gilesi to live underground in arid habitats without further physiological adaptations. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Crosswinds Effect on the Thermal Performance of Wet Cooling Towers Under Variable Operating Conditions

NASA Astrophysics Data System (ADS)

Chen, You Liang; Shi, Yong Feng; Hao, Jian Gang; Chang, Hao; Sun, Feng Zhong

2018-01-01

In order to quantitatively analyze the influence of the variable operating parameters on the cooling performance of natural draft wet cooling towers (NDWCTs), a hot model test system was set up with adjustable ambient temperature and humidity, circulating water flowrate and temperature. In order to apply the hot model test results to the real tower, the crosswind Froude number is defined. The results show that the crosswind has a negative effect on the thermal performance of the cooling tower, and there is a critical crosswind velocity corresponding to the lowest cooling efficiency. According to the crosswind Froude number similarity, when the ambient temperature decreases, or the circulating water flowrate and temperature increase, the cooling tower draft force will increase, and the critical crosswind velocity will increase correspondingly.

Convergent acclimation of leaf photosynthesis and respiration to prevailing ambient temperatures under current and warmer climates in Eucalyptus tereticornis.

PubMed

Aspinwall, Michael J; Drake, John E; Campany, Courtney; Vårhammar, Angelica; Ghannoum, Oula; Tissue, David T; Reich, Peter B; Tjoelker, Mark G

2016-10-01

Understanding physiological acclimation of photosynthesis and respiration is important in elucidating the metabolic performance of trees in a changing climate. Does physiological acclimation to climate warming mirror acclimation to seasonal temperature changes? We grew Eucalyptus tereticornis trees in the field for 14 months inside 9-m tall whole-tree chambers tracking ambient air temperature (Tair ) or ambient Tair  + 3°C (i.e. 'warmed'). We measured light- and CO2 -saturated net photosynthesis (Amax ) and night-time dark respiration (R) each month at 25°C to quantify acclimation. Tree growth was measured, and leaf nitrogen (N) and total nonstructural carbohydrate (TNC) concentrations were determined to investigate mechanisms of acclimation. Warming reduced Amax and R measured at 25°C compared to ambient-grown trees. Both traits also declined as mean daily Tair increased, and did so in a similar way across temperature treatments. Amax and R (at 25°C) both increased as TNC concentrations increased seasonally; these relationships appeared to arise from source-sink imbalances, suggesting potential substrate regulation of thermal acclimation. We found that photosynthesis and respiration each acclimated equivalently to experimental warming and seasonal temperature change of a similar magnitude, reflecting a common, nearly homeostatic constraint on leaf carbon exchange that will be important in governing tree responses to climate warming. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

What do foraging wasps optimize in a variable environment, energy investment or body temperature?

PubMed

Kovac, Helmut; Stabentheiner, Anton; Brodschneider, Robert

2015-11-01

Vespine wasps (Vespula sp.) are endowed with a pronounced ability of endothermic heat production. To show how they balance energetics and thermoregulation under variable environmental conditions, we measured the body temperature and respiration of sucrose foragers (1.5 M, unlimited flow) under variable ambient temperature (T a = 20-35 °C) and solar radiation (20-570 W m(-2)). Results revealed a graduated balancing of metabolic efforts with thermoregulatory needs. The thoracic temperature in the shade depended on ambient temperature, increasing from ~37 to 39 °C. However, wasps used solar heat gain to regulate their thorax temperature at a rather high level at low T a (mean T thorax ~ 39 °C). Only at high T a they used solar heat to reduce their metabolic rate remarkably. A high body temperature accelerated the suction speed and shortened foraging time. As the costs of foraging strongly depended on duration, the efficiency could be significantly increased with a high body temperature. Heat gain from solar radiation enabled the wasps to enhance foraging efficiency at high ambient temperature (T a = 30 °C) by up to 63 %. The well-balanced change of economic strategies in response to environmental conditions minimized costs of foraging and optimized energetic efficiency.

Effect of increased fuel temperature on emissions of oxides of nitrogen from a gas turbine combustor burning ASTM jet-A fuel

NASA Technical Reports Server (NTRS)

Marchionna, N. R.

1974-01-01

An annular gas turbine combustor was tested with heated ASTM Jet-A fuel to determine the effect of increased fuel temperature on the formation of oxides of nitrogen. Fuel temperature ranged from ambient to 700 K. The NOx emission index increased at a rate of 6 percent per 100 K increase in fuel temperature.

Impact of high ambient temperature on unintentional injuries in high-income countries: a narrative systematic literature review

PubMed Central

Otte im Kampe, Eveline; Kovats, Sari; Hajat, Shakoor

2016-01-01

Objectives Given the likelihood of increased hot weather due to climate change, it is crucial to have prevention measures in place to reduce the health burden of high temperatures and heat waves. The aim of this review is to summarise and evaluate the evidence on the effects of summertime weather on unintentional injuries in high-income countries. Design 3 databases (Global Public Health, EMBASE and MEDLINE) were searched by using related keywords and their truncations in the title and abstract, and reference lists of key studies were scanned. Studies reporting heatstroke and intentional injuries were excluded. Results 13 studies met our inclusion criteria. 11 out of 13 studies showed that the risk of unintentional injuries increases with increasing ambient temperatures. On days with moderate temperatures, the increased risk varied between 0.4% and 5.3% for each 1°C increase in ambient temperature. On extreme temperature days, the risk of injuries decreased. 2 out of 3 studies on occupational accidents found an increase in work-related accidents during high temperatures. For trauma hospital admissions, 6 studies reported an increase during hot weather, whereas 1 study found no association. The evidence for impacts on injuries by subgroups such as children, the elderly and drug users was limited and inconsistent. Conclusions The present review describes a broader range of types of unintentional fatal and non-fatal injuries (occupational, trauma hospital admissions, traffic, fire entrapments, poisoning and drug overdose) than has previously been reported. Our review confirms that hot weather can increase the risk of unintentional injuries and accidents in high-income countries. The results are useful for injury prevention strategies. PMID:26868947

Exhaled breath temperature in children: reproducibility and influencing factors.

PubMed

Vermeulen, S; Barreto, M; La Penna, F; Prete, A; Martella, S; Biagiarelli, F; Villa, M P

2014-09-01

This study will investigate the reproducibility and influencing factors of exhaled breath temperature measured with the tidal breathing technique in asthmatic patients and healthy children. Exhaled breath temperature, fractional exhaled nitric oxide, and spirometry were assessed in 124 children (63 healthy and 61 asthmatic), aged 11.2 ± 2.5 year, M/F 73/51. A modified version of the American Thoracic Society questionnaire on the child's present and past respiratory history was obtained from parents. Parents were also asked to provide detailed information on their child's medication use during the previous 4 weeks. Ear temperature, ambient temperature, and relative-ambient humidity were also recorded. Exhaled breath temperature measurements were highly reproducible; the second measurement was higher than the first measurement, consistent with a test-retest situation. In 13 subjects, between-session within-day reproducibility of exhaled breath temperature was still high. Exhaled breath temperature increased with age and relative-ambient humidity. Exhaled breath temperature was comparable in healthy and asthmatic children; when adjusted for potential confounders (i.e. ambient conditions and subject characteristics), thermal values of asthmatic patients exceeded those of the healthy children by 1.1 °C. Normalized exhaled breath temperature, by subtracting ambient temperature, was lower in asthmatic patients treated with inhaled corticosteroids than in those who were corticosteroid-naive. Measurements of exhaled breath temperature are highly reproducible, yet influenced by several factors. Corrected values, i.e. normalized exhaled breath temperature, could help us to assess the effect of therapy with inhaled corticosteroids. More studies are needed to improve the usefulness of the exhaled breath temperature measured with the tidal breathing technique in children.

Low temperature sodium-beta battery

DOEpatents

Farmer, Joseph C

2013-11-19

A battery that will operate at ambient temperature or lower includes an enclosure, a current collector within the enclosure, an anode that will operate at ambient temperature or lower within the enclosure, a cathode that will operate at ambient temperature or lower within the enclosure, and a separator and electrolyte within the enclosure between the anode and the cathode. The anode is a sodium eutectic anode that will operate at ambient temperature or lower and is made of a material that is in a liquid state at ambient temperature or lower. The cathode is a low melting ion liquid cathode that will operate at ambient temperature or lower and is made of a material that is in a liquid state at ambient temperature or lower.

An ignored variable: solution preparation temperature in protein crystallization.

PubMed

Chen, Rui-Qing; Lu, Qin-Qin; Cheng, Qing-Di; Ao, Liang-Bo; Zhang, Chen-Yan; Hou, Hai; Liu, Yong-Ming; Li, Da-Wei; Yin, Da-Chuan

2015-01-19

Protein crystallization is affected by many parameters, among which certain parameters have not been well controlled. The temperature at which the protein and precipitant solutions are mixed (i.e., the ambient temperature during mixing) is such a parameter that is typically not well controlled and is often ignored. In this paper, we show that this temperature can influence protein crystallization. The experimental results showed that both higher and lower mixing temperatures can enhance the success of crystallization, which follows a parabolic curve with an increasing ambient temperature. This work illustrates that the crystallization solution preparation temperature is also an important parameter for protein crystallization. Uncontrolled or poorly controlled room temperature may yield poor reproducibility in protein crystallization.

Cesium Sorption/Desorption Experiments with IONSIV(R) IE-911 in Radioactive Waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, D.D.

2001-02-13

This report describes cesium desorption from IONSIV IE-911 during ambient temperature storage and following temperature increases to 35 and 55 degrees C. This report also describes cesium sorption following return to ambient temperature. The IONSIV IE-911 used in these tests was loaded with cesium from Tank 44F radioactive waste in an ion exchange column test in 1999. Cesium desorbed and resorbed in the presence of Tank 44F waste and simulated waste solutions.

Experimental and casework validation of ambient temperature corrections in forensic entomology.

PubMed

Johnson, Aidan P; Wallman, James F; Archer, Melanie S

2012-01-01

This paper expands on Archer (J Forensic Sci 49, 2004, 553), examining additional factors affecting ambient temperature correction of weather station data in forensic entomology. Sixteen hypothetical body discovery sites (BDSs) in Victoria and New South Wales (Australia), both in autumn and in summer, were compared to test whether the accuracy of correlation was affected by (i) length of correlation period; (ii) distance between BDS and weather station; and (iii) periodicity of ambient temperature measurements. The accuracy of correlations in data sets from real Victorian and NSW forensic entomology cases was also examined. Correlations increased weather data accuracy in all experiments, but significant differences in accuracy were found only between periodicity treatments. We found that a >5°C difference between average values of body in situ and correlation period weather station data was predictive of correlations that decreased the accuracy of ambient temperatures estimated using correlation. Practitioners should inspect their weather data sets for such differences. © 2011 American Academy of Forensic Sciences.

Meteorology and the physical activity of the elderly: the Nakanojo Study

NASA Astrophysics Data System (ADS)

Togo, Fumiharu; Watanabe, Eiji; Park, Hyuntae; Shephard, Roy J.; Aoyagi, Yukitoshi

2005-11-01

Seasonal changes in ambient temperature and day length are thought to modify habitual physical activity. However, relationships between such environmental factors and the daily physical activity of older populations remain unclear. The present study thus examined associations between meteorological variables and the number of steps taken per day by elderly Japanese. Continuous pedometer counts over a 450-day period were collected from 41 healthy subjects (age 71±4 years), none of whom engaged in any specific occupational activity or exercise programs. An electronic physical activity monitor was attached to a belt worn on the left side of the body throughout the day. Daily values for mean ambient temperature, duration of bright sunshine, mean wind speed, mean relative humidity, and precipitation were obtained from local meteorological stations. The day length was calculated from times of sunrise and sunset. Based on the entire group of 41 subjects (ensemble average), a subject’s step count per day decreased exponentially with increasing precipitation (r2=0.19, P<0.05). On days when precipitation was <1 mm, the step count increased with the mean ambient temperature over the range of 2 to 17°C, but decreased over the range 17 29°C. The daily step count also tended to increase with day length, but the regression coefficient of determination attributable to step count and mean ambient temperature (r2=0.32, P<0.05) exceeded that linking the step count and day length (r2=0.13, P<0.05). The influence of other meteorological factors was small (r2≤0.03) and of little practical significance. On days when precipitation is <1 mm, physical activity is associated more strongly with ambient temperature than with day length, duration of bright sunshine, wind speed, or relative humidity. Our findings have practical implications for health promotion efforts designed to increase the physical activity of elderly people consistently in the face of seasonal variations in environmental conditions.

Beyond the classic thermoneutral zone

PubMed Central

Kingma, Boris RM; Frijns, Arjan JH; Schellen, Lisje; van Marken Lichtenbelt, Wouter D

2014-01-01

The thermoneutral zone is defined as the range of ambient temperatures where the body can maintain its core temperature solely through regulating dry heat loss, i.e., skin blood flow. A living body can only maintain its core temperature when heat production and heat loss are balanced. That means that heat transport from body core to skin must equal heat transport from skin to the environment. This study focuses on what combinations of core and skin temperature satisfy the biophysical requirements of being in the thermoneutral zone for humans. Moreover, consequences are considered of changes in insulation and adding restrictions such as thermal comfort (i.e. driver for thermal behavior). A biophysical model was developed that calculates heat transport within a body, taking into account metabolic heat production, tissue insulation, and heat distribution by blood flow and equates that to heat loss to the environment, considering skin temperature, ambient temperature and other physical parameters. The biophysical analysis shows that the steady-state ambient temperature range associated with the thermoneutral zone does not guarantee that the body is in thermal balance at basal metabolic rate per se. Instead, depending on the combination of core temperature, mean skin temperature and ambient temperature, the body may require significant increases in heat production or heat loss to maintain stable core temperature. Therefore, the definition of the thermoneutral zone might need to be reformulated. Furthermore, after adding restrictions on skin temperature for thermal comfort, the ambient temperature range associated with thermal comfort is smaller than the thermoneutral zone. This, assuming animals seek thermal comfort, suggests that thermal behavior may be initiated already before the boundaries of the thermoneutral zone are reached. PMID:27583296

Beyond the classic thermoneutral zone: Including thermal comfort.

PubMed

Kingma, Boris Rm; Frijns, Arjan Jh; Schellen, Lisje; van Marken Lichtenbelt, Wouter D

2014-01-01

The thermoneutral zone is defined as the range of ambient temperatures where the body can maintain its core temperature solely through regulating dry heat loss, i.e., skin blood flow. A living body can only maintain its core temperature when heat production and heat loss are balanced. That means that heat transport from body core to skin must equal heat transport from skin to the environment. This study focuses on what combinations of core and skin temperature satisfy the biophysical requirements of being in the thermoneutral zone for humans. Moreover, consequences are considered of changes in insulation and adding restrictions such as thermal comfort (i.e. driver for thermal behavior). A biophysical model was developed that calculates heat transport within a body, taking into account metabolic heat production, tissue insulation, and heat distribution by blood flow and equates that to heat loss to the environment, considering skin temperature, ambient temperature and other physical parameters. The biophysical analysis shows that the steady-state ambient temperature range associated with the thermoneutral zone does not guarantee that the body is in thermal balance at basal metabolic rate per se. Instead, depending on the combination of core temperature, mean skin temperature and ambient temperature, the body may require significant increases in heat production or heat loss to maintain stable core temperature. Therefore, the definition of the thermoneutral zone might need to be reformulated. Furthermore, after adding restrictions on skin temperature for thermal comfort, the ambient temperature range associated with thermal comfort is smaller than the thermoneutral zone. This, assuming animals seek thermal comfort, suggests that thermal behavior may be initiated already before the boundaries of the thermoneutral zone are reached.

Strain-cycling fatigue behavior of ten structural metals tested in liquid helium (4 K), in liquid nitrogen (78 K), and in ambient air (300 K)

NASA Technical Reports Server (NTRS)

Nachtigall, A. J.

1974-01-01

Strain-cycling fatigue behavior of 10 different structural alloys and metals was investigated in liquid helium (4 K), in liquid nitrogen (78 K), and in ambient air (300 K). At high cyclic lives, fatigue resistance increased with decreasing temperature for all the materials investigated. At low cyclic lives, fatigue resistance generally decreased with decreasing temperature for the materials investigated. Only for Inconel 718 did fatigue resistance increase with decreasing temperature over the entire life range investigated. Comparison of the experimental fatigue behavior with that predicted by the Manson method of universal slopes showed that the fatigue behavior of these materials can be predicted for cryogenic temperatures by using material tensile properties obtained at those same temperatures.

Energetic Optimisation of Foraging Honeybees: Flexible Change of Strategies in Response to Environmental Challenges

PubMed Central

Stabentheiner, Anton; Kovac, Helmut

2014-01-01

Heterothermic insects like honeybees, foraging in a variable environment, face the challenge of keeping their body temperature high to enable immediate flight and to promote fast exploitation of resources. Because of their small size they have to cope with an enormous heat loss and, therefore, high costs of thermoregulation. This calls for energetic optimisation which may be achieved by different strategies. An ‘economizing’ strategy would be to reduce energetic investment whenever possible, for example by using external heat from the sun for thermoregulation. An ‘investment-guided’ strategy, by contrast, would be to invest additional heat production or external heat gain to optimize physiological parameters like body temperature which promise increased energetic returns. Here we show how honeybees balance these strategies in response to changes of their local microclimate. In a novel approach of simultaneous measurement of respiration and body temperature foragers displayed a flexible strategy of thermoregulatory and energetic management. While foraging in shade on an artificial flower they did not save energy with increasing ambient temperature as expected but acted according to an ‘investment-guided’ strategy, keeping the energy turnover at a high level (∼56–69 mW). This increased thorax temperature and speeded up foraging as ambient temperature increased. Solar heat was invested to increase thorax temperature at low ambient temperature (‘investment-guided’ strategy) but to save energy at high temperature (‘economizing’ strategy), leading to energy savings per stay of ∼18–76% in sunshine. This flexible economic strategy minimized costs of foraging, and optimized energetic efficiency in response to broad variation of environmental conditions. PMID:25162211

An Investigation on Attributes of Ambient Temperature and Diurnal Temperature Range on Mortality in Five East-Asian Countries.

PubMed

Lee, Whan-Hee; Lim, Youn-Hee; Dang, Tran Ngoc; Seposo, Xerxes; Honda, Yasushi; Guo, Yue-Liang Leon; Jang, Hye-Min; Kim, Ho

2017-08-31

Interest in the health effects of extremely low/high ambient temperature and the diurnal temperature range (DTR) on mortality as representative indices of temperature variability is growing. Although numerous studies have reported on these indices independently, few studies have provided the attributes of ambient temperature and DTR related to mortality, concurrently. In this study, we aimed to investigate and compare the mortality risk attributable to ambient temperature and DTR. The study included data of 63 cities in five East-Asian countries/regions during various periods between 1972 and 2013. The attributable risk of non-accidental death to ambient temperature was 9.36% (95% confidence interval [CI]: 8.98-9.69%) and to DTR was 0.59% (95% CI: 0.53-0.65%). The attributable cardiovascular mortality risks to ambient temperature (15.63%) and DTR (0.75%) are higher than the risks to non-accidental/respiratory-related mortality. We verified that ambient temperature plays a larger role in temperature-associated mortality, and cardiovascular mortality is susceptible to ambient temperature and DTR.

The growth temperature and measurement temperature dependences of soft magnetic properties and effective damping parameter of (FeCo)-Al alloy thin films

NASA Astrophysics Data System (ADS)

Ariake, Yusuke; Wu, Shuang; Kanada, Isao; Mewes, Tim; Tanaka, Yoshitomo; Mankey, Gary; Mewes, Claudia; Suzuki, Takao

2018-05-01

The soft magnetic properties and effective damping parameters of Fe73Co25Al2 alloy thin films are discussed. The effective damping parameter αeff measured by ferromagnetic resonance for the 10 nm-thick sample is nearly constant (≈0.004 ± 0.0008) for a growth temperature Ts from ambient to 200 °C, and then tends to decrease for higher temperatures and αeff is 0.002 ± 0.0004 at Ts = 300 °C. For the 80 nm-thick sample, the αeff seems to increase with Ts from αeff = 0.001 ± 0.0002 at Ts = ambient to αeff = 0.002 ± 0.0004. The αeff is found nearly constant (αeff = 0.004 ± 0.0008) over a temperature range from 10 to 300 K for the 10 nm films with the different Ts (ambient, 100 and 200 °C). Together with an increasing non-linearity of the frequency dependence of the linewidth at low Ts, extrinsic contributions such as two-magnon scattering dominate the observed temperature dependence of effective damping and linewidth.

Effect of temperature on the electric breakdown strength of dielectric elastomer

NASA Astrophysics Data System (ADS)

Liu, Lei; Chen, Hualing; Sheng, Junjie; Zhang, Junshi; Wang, Yongquan; Jia, Shuhai

2014-03-01

DE (dielectric elastomer) is one of the most promising artificial muscle materials for its large strain over 100% under driving voltage. However, to date, dielectric elastomer actuators (DEAs) are prone to failure due to the temperature-dependent electric breakdown. Previously studies had shown that the electrical breakdown strength was mainly related to the temperature-dependent elasticity modulus and the permittivity of dielectric substances. This paper investigated the influence of ambient temperature on the electric breakdown strength of DE membranes (VHB4910 3M). The electric breakdown experiment of the DE membrane was conducted at different ambient temperatures and pre-stretch levels. The real breakdown strength was obtained by measuring the deformation and the breakdown voltage simultaneously. Then, we found that with the increase of the environment temperature, the electric breakdown strength decreased obviously. Contrarily, the high pre-stretch level led to the large electric breakdown strength. What is more, we found that the deformations of DEs were strongly dependent on the ambient temperature.

Genetic Algorithm (GA)-Based Inclinometer Layout Optimization.

PubMed

Liang, Weijie; Zhang, Ping; Chen, Xianping; Cai, Miao; Yang, Daoguo

2015-04-17

This paper presents numerical simulation results of an airflow inclinometer with sensitivity studies and thermal optimization of the printed circuit board (PCB) layout for an airflow inclinometer based on a genetic algorithm (GA). Due to the working principle of the gas sensor, the changes of the ambient temperature may cause dramatic voltage drifts of sensors. Therefore, eliminating the influence of the external environment for the airflow is essential for the performance and reliability of an airflow inclinometer. In this paper, the mechanism of an airflow inclinometer and the influence of different ambient temperatures on the sensitivity of the inclinometer will be examined by the ANSYS-FLOTRAN CFD program. The results show that with changes of the ambient temperature on the sensing element, the sensitivity of the airflow inclinometer is inversely proportional to the ambient temperature and decreases when the ambient temperature increases. GA is used to optimize the PCB thermal layout of the inclinometer. The finite-element simulation method (ANSYS) is introduced to simulate and verify the results of our optimal thermal layout, and the results indicate that the optimal PCB layout greatly improves (by more than 50%) the sensitivity of the inclinometer. The study may be useful in the design of PCB layouts that are related to sensitivity improvement of gas sensors.

Genetic Algorithm (GA)-Based Inclinometer Layout Optimization

PubMed Central

Liang, Weijie; Zhang, Ping; Chen, Xianping; Cai, Miao; Yang, Daoguo

2015-01-01

This paper presents numerical simulation results of an airflow inclinometer with sensitivity studies and thermal optimization of the printed circuit board (PCB) layout for an airflow inclinometer based on a genetic algorithm (GA). Due to the working principle of the gas sensor, the changes of the ambient temperature may cause dramatic voltage drifts of sensors. Therefore, eliminating the influence of the external environment for the airflow is essential for the performance and reliability of an airflow inclinometer. In this paper, the mechanism of an airflow inclinometer and the influence of different ambient temperatures on the sensitivity of the inclinometer will be examined by the ANSYS-FLOTRAN CFD program. The results show that with changes of the ambient temperature on the sensing element, the sensitivity of the airflow inclinometer is inversely proportional to the ambient temperature and decreases when the ambient temperature increases. GA is used to optimize the PCB thermal layout of the inclinometer. The finite-element simulation method (ANSYS) is introduced to simulate and verify the results of our optimal thermal layout, and the results indicate that the optimal PCB layout greatly improves (by more than 50%) the sensitivity of the inclinometer. The study may be useful in the design of PCB layouts that are related to sensitivity improvement of gas sensors. PMID:25897500

Low-Temperature Friction-Stir Welding of 2024 Aluminum

NASA Technical Reports Server (NTRS)

Benavides, S.; Li, Y.; Murr, L. E.; Brown, D.; McClure, J. C.

1998-01-01

Solid state friction-stir welding (FSW) has been demonstrated to involve dynamic recrystallization producing ultra-fine, equiaxed grain structures to facilitate superplastic deformation as the welding or joining mechanism. However, the average residual, equiaxed, grain size in the weld zone has ranged from roughly 0.5 micron to slightly more than 10 micron, and the larger weld zone grain sizes have been characterized as residual or static grain growth as a consequence of the temperatures in the weld zone (where center-line temperatures in the FSW of 6061 Al have been shown to be as high as 480C or -0.8 T(sub M) where T(sub M) is the absolute melting temperature)). In addition, the average residual weld zone grain size has been observed to increase near the top of the weld, and to decrease with distance on either side of the weld-zone centerline, an d this corresponds roughly to temperature variations within the weld zone. The residual grain size also generally decreases with decreasing FSW tool rotation speed. These observations are consistent with the general rules for recrystallization where the recrystallized grain size decreases with increasing strain (or deformation) at constant strain rate, or with increasing strain-rate, or with increasing strain rate at constant strain; especially at lower ambient temperatures, (or annealing temperatures). Since the recrystallization temperature also decreases with increasing strain rate, the FSW process is somewhat complicated because the ambient temperature, the frictional heating fraction, and the adiabatic heating fraction )proportional to the product of strain and strain-rate) will all influence both the recrystallization and growth within the FSW zone. Significantly reducing the ambient temperature of the base metal or work pieces to be welded would be expected to reduce the residual weld-zone grain size. The practical consequences of this temperature reduction would be the achievement of low temperature welding. This study compares the residual grain sizes and microstructures in 2024 Al friction-stir welded at room temperature (about 30C and low temperature (-30C).

High Ambient Temperature Represses Anthocyanin Biosynthesis through Degradation of HY5

PubMed Central

Kim, Sara; Hwang, Geonhee; Lee, Seulgi; Zhu, Jia-Ying; Paik, Inyup; Nguyen, Thom Thi; Kim, Jungmook; Oh, Eunkyoo

2017-01-01

Anthocyanins are flavonoid compounds that protect plant tissues from many environmental stresses including high light irradiance, freezing temperatures, and pathogen infection. Regulation of anthocyanin biosynthesis is intimately associated with environmental changes to enhance plant survival under stressful environmental conditions. Various factors, such as UV, visible light, cold, osmotic stress, and pathogen infection, can induce anthocyanin biosynthesis. In contrast, high temperatures are known to reduce anthocyanin accumulation in many plant species, even drastically in the skin of fruits such as grape berries and apples. However, the mechanisms by which high temperatures regulate anthocyanin biosynthesis in Arabidopsis thaliana remain largely unknown. Here, we show that high ambient temperatures repress anthocyanin biosynthesis through the E3 ubiquitin ligase CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) and the positive regulator of anthocyanin biosynthesis ELONGATED HYPOCOTYL5 (HY5). We show that an increase in ambient temperature decreases expression of genes required in both the early and late steps of the anthocyanin biosynthesis pathway in Arabidopsis seedlings. As a result, seedlings grown at a high temperature (28°C) accumulate less anthocyanin pigment than those grown at a low temperature (17°C). We further show that high temperature induces the degradation of the HY5 protein in a COP1 activity-dependent manner. In agreement with this finding, anthocyanin biosynthesis and accumulation do not respond to ambient temperature changes in cop1 and hy5 mutant plants. The degradation of HY5 derepresses the expression of MYBL2, which partially mediates the high temperature repression of anthocyanin biosynthesis. Overall, our study demonstrates that high ambient temperatures repress anthocyanin biosynthesis through a COP1-HY5 signaling module. PMID:29104579

Ambient temperature and cardiovascular biomarkers in a repeated-measure study in healthy adults: A novel biomarker index approach.

PubMed

Wu, Shaowei; Yang, Di; Pan, Lu; Shan, Jiao; Li, Hongyu; Wei, Hongying; Wang, Bin; Huang, Jing; Baccarelli, Andrea A; Shima, Masayuki; Deng, Furong; Guo, Xinbiao

2017-07-01

Associations of ambient temperature with cardiovascular morbidity and mortality have been well documented in numerous epidemiological studies, but the underlying pathways remain unclear. We investigated whether systemic inflammation, coagulation, systemic oxidative stress, antioxidant activity and endothelial function may be the mechanistic pathways associated with ambient temperature. Forty study participants underwent repeated blood collections for 12 times in Beijing, China in 2010-2011. Ambient temperature and air pollution data were measured in central monitors close to student residences. We created five indices as the sum of weighted biomarker percentiles to represent the overall levels of 15 cardiovascular biomarkers in five pathways (systemic inflammation: hs-CRP, TNF-α and fibrinogen; coagulation: fibrinogen, PAI-1, tPA, vWF and sP-selectin; systemic oxidative stress: Ox-LDL and sCD36: antioxidant activity: EC-SOD and GPX1; and endothelial function: ET-1, E-selectin, ICAM-1 and VCAM-1). We used generalized mixed-effects models to estimate temperature effects controlling for air pollution and other covariates. There were significant decreasing trends in the adjusted means of biomarker indices over the lowest to the highest quartiles of daily temperatures before blood collection. A 10°C decrease at 2-d average daily temperature were associated with increases of 2.5% [95% confidence interval (CI): 0.7, 4.2], 1.6% (95% CI: 0.1, 3.1), 2.7% (95% CI: 0.5, 4.8), 5.5% (95% CI: 3.8, 7.3) and 2.0% (95% CI: 0.3, 3.8) in the indices for systemic inflammation, coagulation, systemic oxidative stress, antioxidant activity and endothelial function, respectively. In contrast, the associations between ambient temperature and individual biomarkers had substantial variation in magnitude and strength. The altered cardiovascular biomarker profiles in healthy adults associated with ambient temperature changes may help explain the temperature-related cardiovascular morbidity and mortality. The biomarker index approach may serve as a novel tool to capture ambient temperature effects. Copyright © 2017. Published by Elsevier Inc.

Effects of Ambient Temperature and Relative Humidity on Subsurface Defect Detection in Concrete Structures by Active Thermal Imaging.

PubMed

Tran, Quang Huy; Han, Dongyeob; Kang, Choonghyun; Haldar, Achintya; Huh, Jungwon

2017-07-26

Active thermal imaging is an effective nondestructive technique in the structural health monitoring field, especially for concrete structures not exposed directly to the sun. However, the impact of meteorological factors on the testing results is considerable and should be studied in detail. In this study, the impulse thermography technique with halogen lamps heat sources is used to detect defects in concrete structural components that are not exposed directly to sunlight and not significantly affected by the wind, such as interior bridge box-girders and buildings. To consider the effect of environment, ambient temperature and relative humidity, these factors are investigated in twelve cases of testing on a concrete slab in the laboratory, to minimize the influence of wind. The results showed that the absolute contrast between the defective and sound areas becomes more apparent with an increase of ambient temperature, and it increases at a faster rate with large and shallow delaminations than small and deep delaminations. In addition, the absolute contrast of delamination near the surface might be greater under a highly humid atmosphere. This study indicated that the results obtained from the active thermography technique will be more apparent if the inspection is conducted on a day with high ambient temperature and humidity.

Repeated nitrous oxide exposure in rats causes a thermoregulatory sign-reversal with concurrent activation of opposing thermoregulatory effectors

PubMed Central

Ramsay, Douglas S; Woods, Stephen C; Kaiyala, Karl J

2014-01-01

Initial administration of 60% nitrous oxide (N2O) to rats at an ambient temperature of 21°C decreases core temperature (Tc), primarily via increased heat loss (HL). Over repeated N2O administrations, rats first develop tolerance to this hypothermia and subsequently exhibit hyperthermia (a sign-reversal) due primarily to progressive increases in heat production (HP). When rats initially receive 60% N2O in a thermal gradient, they become hypothermic while selecting cooler ambient temperatures that facilitate HL. This study investigated whether rats repeatedly administered 60% N2O in a thermal gradient would use the gradient to behaviorally facilitate, or oppose, the development of chronic tolerance and a hyperthermic sign-reversal. Male Long-Evans rats (N = 16) received twelve 3-h administrations of 60% N2O in a gas-tight, live-in thermal gradient. Hypothermia (Sessions 1–3), complete chronic tolerance (Sessions 4–6), and a subsequent transient hyperthermic sign-reversal (Sessions 7–12) sequentially developed. Despite the progressive recovery and eventual hyperthermic sign-reversal of Tc, rats consistently selected cooler ambient temperatures during all N2O administrations. A final 60% N2O administration in a total calorimeter indicated that the hyperthermic sign-reversal resulted primarily from increased HP. Thus, rats did not facilitate chronic tolerance development by moving to warmer locations in the gradient, and instead selected cooler ambient temperatures while simultaneously increasing autonomic HP. The inefficient concurrent activation of opposing effectors and the development of a sign-reversal are incompatible with homeostatic models of drug-adaptation and may be better interpreted using a model of drug-induced allostasis. PMID:25938127

Increased temperature mitigates the effects of ocean acidification on the calcification of juvenile Pocillopora damicornis, but at a cost

NASA Astrophysics Data System (ADS)

Jiang, Lei; Zhang, Fang; Guo, Ming-Lan; Guo, Ya-Juan; Zhang, Yu-Yang; Zhou, Guo-Wei; Cai, Lin; Lian, Jian-Sheng; Qian, Pei-Yuan; Huang, Hui

2018-03-01

This study tested the interactive effects of increased seawater temperature and CO2 partial pressure ( pCO2) on the photochemistry, bleaching, and early growth of the reef coral Pocillopora damicornis. New recruits were maintained at ambient or high temperature (29 or 30.8 °C) and pCO2 ( 500 and 1100 μatm) in a full-factorial experiment for 3 weeks. Neither a sharp decline in photochemical efficiency (Fv/Fm) nor evident bleaching was observed at high temperature and/or high pCO2. Furthermore, elevated temperature greatly promoted lateral growth and calcification, while polyp budding exhibited temperature-dependent responses to pCO2. High pCO2 depressed calcification by 28% at ambient temperature, but did not impact calcification at 30.8 °C. Interestingly, elevated temperature in concert with high pCO2 significantly retarded the budding process. These results suggest that increased temperature can mitigate the adverse effects of acidification on the calcification of juvenile P. damicornis, but at a substantial cost to asexual budding.

An ignored variable: solution preparation temperature in protein crystallization

PubMed Central

Chen, Rui-Qing; Lu, Qin-Qin; Cheng, Qing-Di; Ao, Liang-Bo; Zhang, Chen-Yan; Hou, Hai; Liu, Yong-Ming; Li, Da-Wei; Yin, Da-Chuan

2015-01-01

Protein crystallization is affected by many parameters, among which certain parameters have not been well controlled. The temperature at which the protein and precipitant solutions are mixed (i.e., the ambient temperature during mixing) is such a parameter that is typically not well controlled and is often ignored. In this paper, we show that this temperature can influence protein crystallization. The experimental results showed that both higher and lower mixing temperatures can enhance the success of crystallization, which follows a parabolic curve with an increasing ambient temperature. This work illustrates that the crystallization solution preparation temperature is also an important parameter for protein crystallization. Uncontrolled or poorly controlled room temperature may yield poor reproducibility in protein crystallization. PMID:25597864

Reduced diurnal temperature range does not change warming impacts on ecosystem carbon balance of Mediterranean grassland mesocosms

DOE PAGES

Phillips, Claire L.; Gregg, Jillian W.; Wilson, John K.

2011-11-01

Daily minimum temperature (T min) has increased faster than daily maximum temperature (T max) in many parts of the world, leading to decreases in diurnal temperature range (DTR). Projections suggest these trends are likely to continue in many regions, particularly northern latitudes and in arid regions. Despite wide speculation that asymmetric warming has different impacts on plant and ecosystem production than equal-night-and-day warming, there has been little direct comparison of these scenarios. Reduced DTR has also been widely misinterpreted as a result of night-only warming, when in fact T min occurs near dawn, indicating higher morning as well as nightmore » temperatures. We report on the first experiment to examine ecosystem-scale impacts of faster increases in T min than T max, using precise temperature controls to create realistic diurnal temperature profiles with gradual day-night temperature transitions and elevated early morning as well as night temperatures. Studying a constructed grassland ecosystem containing species native to Oregon, USA, we found the ecosystem lost more carbon at elevated than ambient temperatures, but was unaffected by the 3ºC difference in DTR between symmetric warming (constantly ambient +3.5ºC) and asymmetric warming (dawn T min=ambient +5ºC, afternoon T max= ambient +2ºC). Reducing DTR had no apparent effect on photosynthesis, likely because temperatures were most different in the morning and late afternoon when light was low. Respiration was also similar in both warming treatments, because respiration temperature sensitivity was not sufficient to respond to the limited temperature differences between asymmetric and symmetric warming. We concluded that changes in daily mean temperatures, rather than changes in T min/T max, were sufficient for predicting ecosystem carbon fluxes in this reconstructed Mediterranean grassland system.« less

Effect of ambient temperature on the thermal profile of the human forearm, hand, and fingers

NASA Technical Reports Server (NTRS)

Montgomery, L. D.; Williams, B. A.

1976-01-01

Forearm, hand, and finger skin temperatures were measured on the right and left sides of seven resting men. The purpose was to determine the bilateral symmetry of these segmental temperature profiles at ambient temperatures from 10 to 45 C. Thermistors placed on the right and left forearms, hands, and index fingers were used to monitor the subjects until equilibration was reached at each ambient temperature. Additionally, thermal profiles of both hands were measured with copper-constantan thermocouples. During one experimental condition (23 C ambient), rectal, ear canal, and 24 skin temperatures were measured on each subject. Average body and average skin temperatures are given for each subject at the 23 C ambient condition. Detailed thermal profiles are also presented for the dorsal, ventral, and circumferential left forearm, hand, and finger skin temperatures at 23 C ambient. No significant differences were found between the mean skin temperatures of the right and left contralateral segments at any of the selected ambient temperatures.

Comparison of the effects of symmetric and asymmetric temperature elevation and CO2 enrichment on yield and evapotranspiration of winter wheat (Triticum aestivum L.)

PubMed Central

Qiao, Yunzhou; Liu, Huiling; Kellomäki, Seppo; Peltola, Heli; Liu, Yueyan; Dong, Baodi; Shi, Changhai; Zhang, Huizhen; Zhang, Chao; Gong, Jinnan; Si, Fuyan; Li, Dongxiao; Zheng, Xin; Liu, Mengyu

2014-01-01

Under the changing climate, asymmetric warming pattern would be more likely during day and night time, instead of symmetric one. Concurrently, the growth responses and water use of plants may be different compared with those estimated based on symmetric warming. In this work, it was compared with the effects of symmetric (ETs) and asymmetric (ETa) elevation of temperature alone, and in interaction with elevated carbon dioxide concentration (EC), on the grain yield (GY) and evapotranspiration in winter wheat (Triticum aestivum L.) based on pot experiment in the North China Plain (NCP). The experiment was carried out in six enclosed-top chambers with following climate treatments: (1) ambient temperature and ambient CO2 (CON), (2) ambient temperature and elevated CO2 (EC), (3) elevated temperature and ambient CO2 (ETs; ETa), and (4) elevated temperature and elevated CO2 (ECETs, ECETa). In symmetric warming, temperature was increased by 3°C and in asymmetric one by 3.5°C during night and 2.5°C during daytime, respectively. As a result, GY was in ETa and ETs 15.6 (P < 0.05) and 10.3% (P < 0.05) lower than that in CON. In ECETs and ECETa treatments, GY was 14.9 (P < 0.05) and 9.1% (P < 0.05) higher than that in CON. Opposite to GY, evapotranspiration was 7.8 (P < 0.05) and 17.9% (P < 0.05) higher in ETa and ETs treatments and 7.2 (P < 0.05) and 2.1% (P > 0.05) lower in ECETs and ECETa treatments compared with CON. Thus, GY of wheat could be expected to increase under the changing climate with concurrent elevation of CO2 and temperature as a result of increased WUE under the elevated CO2. However, the gain would be lower under ETa than that estimated based on ETs due to higher evapotranspiration. PMID:24963392

Comparison of the effects of symmetric and asymmetric temperature elevation and CO2 enrichment on yield and evapotranspiration of winter wheat (Triticum aestivum L.).

PubMed

Qiao, Yunzhou; Liu, Huiling; Kellomäki, Seppo; Peltola, Heli; Liu, Yueyan; Dong, Baodi; Shi, Changhai; Zhang, Huizhen; Zhang, Chao; Gong, Jinnan; Si, Fuyan; Li, Dongxiao; Zheng, Xin; Liu, Mengyu

2014-05-01

Under the changing climate, asymmetric warming pattern would be more likely during day and night time, instead of symmetric one. Concurrently, the growth responses and water use of plants may be different compared with those estimated based on symmetric warming. In this work, it was compared with the effects of symmetric (ETs) and asymmetric (ETa) elevation of temperature alone, and in interaction with elevated carbon dioxide concentration (EC), on the grain yield (GY) and evapotranspiration in winter wheat (Triticum aestivum L.) based on pot experiment in the North China Plain (NCP). The experiment was carried out in six enclosed-top chambers with following climate treatments: (1) ambient temperature and ambient CO2 (CON), (2) ambient temperature and elevated CO2 (EC), (3) elevated temperature and ambient CO2 (ETs; ETa), and (4) elevated temperature and elevated CO2 (ECETs, ECETa). In symmetric warming, temperature was increased by 3°C and in asymmetric one by 3.5°C during night and 2.5°C during daytime, respectively. As a result, GY was in ETa and ETs 15.6 (P < 0.05) and 10.3% (P < 0.05) lower than that in CON. In ECETs and ECETa treatments, GY was 14.9 (P < 0.05) and 9.1% (P < 0.05) higher than that in CON. Opposite to GY, evapotranspiration was 7.8 (P < 0.05) and 17.9% (P < 0.05) higher in ETa and ETs treatments and 7.2 (P < 0.05) and 2.1% (P > 0.05) lower in ECETs and ECETa treatments compared with CON. Thus, GY of wheat could be expected to increase under the changing climate with concurrent elevation of CO2 and temperature as a result of increased WUE under the elevated CO2. However, the gain would be lower under ETa than that estimated based on ETs due to higher evapotranspiration.

Microbial responses to multi-factor climate change: effects on soil enzymes.

PubMed

Steinweg, J Megan; Dukes, Jeffrey S; Paul, Eldor A; Wallenstein, Matthew D

2013-01-01

The activities of extracellular enzymes, the proximate agents of decomposition in soils, are known to depend strongly on temperature, but less is known about how they respond to changes in precipitation patterns, and the interaction of these two components of climate change. Both enzyme production and turnover can be affected by changes in temperature and soil moisture, thus it is difficult to predict how enzyme pool size may respond to altered climate. Soils from the Boston-Area Climate Experiment (BACE), which is located in an old field (on abandoned farmland), were used to examine how climate variables affect enzyme activities and microbial biomass carbon (MBC) in different seasons and in soils exposed to a combination of three levels of precipitation treatments (ambient, 150% of ambient during growing season, and 50% of ambient year-round) and four levels of warming treatments (unwarmed to ~4°C above ambient) over the course of a year. Warming, precipitation and season had very little effect on potential enzyme activity. Most models assume that enzyme dynamics follow microbial biomass, because enzyme production should be directly controlled by the size and activity of microbial biomass. We observed differences among seasons and treatments in mass-specific potential enzyme activity, suggesting that this assumption is invalid. In June 2009, mass-specific potential enzyme activity, using chloroform fumigation-extraction MBC, increased with temperature, peaking under medium warming and then declining under the highest warming. This finding suggests that either enzyme production increased with temperature or turnover rates decreased. Increased maintenance costs associated with warming may have resulted in increased mass-specific enzyme activities due to increased nutrient demand. Our research suggests that allocation of resources to enzyme production could be affected by climate-induced changes in microbial efficiency and maintenance costs.

Effects of environmental variables on surface temperature of breeding adult female northern elephant seals, Mirounga angustirostris, and pups.

PubMed

Codde, Sarah A; Allen, Sarah G; Houser, Dorian S; Crocker, Daniel E

2016-10-01

Pinnipeds spend extended periods of time on shore during breeding, and some temperate species retreat to the water if exposed to high ambient temperatures. However, female northern elephant seals (Mirounga angustirostris) with pups generally avoid the water, presumably to minimize risks to pups or male harassment. Little is known about how ambient temperature affects thermoregulation of well insulated females while on shore. We used a thermographic camera to measure surface temperature (T s ) of 100 adult female elephant seals and their pups during the breeding season at Point Reyes National Seashore, yielding 782 thermograms. Environmental variables were measured by an onsite weather station. Environmental variables, especially solar radiation and ambient temperature, were the main determinants of mean and maximum T s of both females and pups. An average of 16% of the visible surface of both females and pups was used as thermal windows to facilitate heat loss and, for pups, this area increased with solar radiation. Thermal window area of females increased with mean T s until approximately 26°C and then declined. The T s of both age classes were warmer than ambient temperature and had a large thermal gradient with the environment (female mean 11.2±0.2°C; pup mean 14.2±0.2°C). This large gradient suggests that circulatory adjustments to bypass blubber layers were sufficient to allow seals to dissipate heat under most environmental conditions. We observed the previously undescribed behavior of females and pups in the water and determined that solar radiation affected this behavior. This may have been possible due to the calm waters at the study site, which reduced the risk of neonates drowning. These results may predict important breeding habitat features for elephant seals as solar radiation and ambient temperatures change in response to changing climate. Published by Elsevier Ltd.

Interactions Between Housing Density and Ambient Temperature in the Cage Environment: Effects on Mouse Physiology and Behavior.

PubMed

Toth, Linda A; Trammell, Rita A; Ilsley-Woods, Megan

2015-11-01

To determine how housing density and ambient temperature interact to influence the physiology and behavior of mice, we systematically varied housing density (1 to 5 mice per cage) and ambient temperature (22, 26, or 30 °C) and measured effects on body weight, food intake, diurnal patterns of locomotor activity and core temperature, fecal corticosterone, and serum cytokine and adipokine panels. Temperatures inside cages housing 5 mice were 1 to 2 °C higher than the ambient temperature. As the housing density decreased, in-cage temperatures began to fall at a density of 2 or 3 mice per cage and did not differ from ambient temperature at 1 mouse per cage. Ambient temperature, but not housing density, significantly affected food intake. Although neither ambient temperature nor housing density affected core temperature or activity, hyperthermia and behavioral activation occurred during the 12-h period after cage change. Fecal concentrations of corticosterone metabolites and serum cytokines, chemokines, insulin, and leptin were not influenced by cage density and were only sporadically influenced by ambient temperature. Our data document that the number of mice housed per cage influences the intracage environmental conditions and that ambient temperature influences food intake even when temperatures are within or near recommended or thermoneutral ranges. We conclude that investigators should be cautious when changing the number of mice housed in a cage over the course of a study, because doing so significantly alters the cage environment to which remaining mice are exposed.

Interactions Between Housing Density and Ambient Temperature in the Cage Environment: Effects on Mouse Physiology and Behavior

PubMed Central

Toth, Linda A; Trammell, Rita A; Ilsley-Woods, Megan

2015-01-01

To determine how housing density and ambient temperature interact to influence the physiology and behavior of mice, we systematically varied housing density (1 to 5 mice per cage) and ambient temperature (22, 26, or 30 °C) and measured effects on body weight, food intake, diurnal patterns of locomotor activity and core temperature, fecal corticosterone, and serum cytokine and adipokine panels. Temperatures inside cages housing 5 mice were 1 to 2 °C higher than the ambient temperature. As the housing density decreased, in-cage temperatures began to fall at a density of 2 or 3 mice per cage and did not differ from ambient temperature at 1 mouse per cage. Ambient temperature, but not housing density, significantly affected food intake. Although neither ambient temperature nor housing density affected core temperature or activity, hyperthermia and behavioral activation occurred during the 12-h period after cage change. Fecal concentrations of corticosterone metabolites and serum cytokines, chemokines, insulin, and leptin were not influenced by cage density and were only sporadically influenced by ambient temperature. Our data document that the number of mice housed per cage influences the intracage environmental conditions and that ambient temperature influences food intake even when temperatures are within or near recommended or thermoneutral ranges. We conclude that investigators should be cautious when changing the number of mice housed in a cage over the course of a study, because doing so significantly alters the cage environment to which remaining mice are exposed. PMID:26632780

40 CFR 53.55 - Test for effect of variations in power line voltage and ambient temperature.

Code of Federal Regulations, 2010 CFR

2010-07-01

... measurement accuracy. (iv) Coefficient of variability measurement accuracy. (v) Ambient air temperature... line voltage and ambient temperature. 53.55 Section 53.55 Protection of Environment ENVIRONMENTAL... power line voltage and ambient temperature. (a) Overview. (1) This test procedure is a combined...

14 CFR 25.1527 - Ambient air temperature and operating altitude.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited by...

14 CFR 25.1527 - Ambient air temperature and operating altitude.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited by...

14 CFR 25.1527 - Ambient air temperature and operating altitude.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited by...

14 CFR 25.1527 - Ambient air temperature and operating altitude.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited by...

PhybalSIT — Fatigue Assessment and Life Time Calculation of the Ductile Cast Iron EN-GJS-600 at Ambient and Elevated Temperatures

NASA Astrophysics Data System (ADS)

Jost, Benjamin; Klein, Marcus; Eifler, Dietmar

This paper focuses on the ductile cast iron EN-GJS-600 which is often used for components of combustion engines. Under service conditions, those components are mechanically loaded at different temperatures. Therefore, this investigation targets at the fatigue behavior of EN-GJS-600 at ambient and elevated temperatures. Light and scanning electron microscopic investigations were done to characterize the sphericity of the graphite as well as the ferrite, pearlite and graphite fraction. At elevated temperatures, the consideration of dynamic strain ageing effects is of major importance. In total strain increase, temperature increase and constant total strain amplitude tests, the plastic strain amplitude, the stress amplitude, the change in temperature and the change in electrical resistance were measured. The measured values depend on plastic deformation processes in the bulk of the specimens and at the interfaces between matrix and graphite. The fatigue behavior of EN-GJS-600 is dominated by cyclic hardening processes. The physically based fatigue life calculation "PHYBALSIT" (SIT = strain increase test) was developed for total strain controlled fatigue tests. Only one temperature increase test is necessary to determine the temperature interval of pronounced dynamic strain ageing effects.

The effect of ambient temperature, habitat quality and individual age on incubation behaviour and incubation feeding in a socially monogamous songbird.

PubMed

Amininasab, Seyed Mehdi; Kingma, Sjouke A; Birker, Martje; Hildenbrandt, Hanno; Komdeur, Jan

Incubation is an important aspect of avian life history. The behaviour is energetically costly, and investment in incubation strategies within species, like female nest attentiveness and the feeding by the non-incubating partner during incubation, can therefore vary depending on environmental and individual characteristics. However, little is known about the combined effect of these characteristics. We investigated the importance of ambient temperature, habitat quality, and bird age on female incubation behaviour and male feeding of the incubating female (incubation feeding) in blue tits Cyanistes caeruleus , a socially monogamous songbird. An increase in ambient temperature resulted in a higher nest temperature, and this enabled females to increase the time off the nest for self-maintenance activities. Probably as a consequence of this, an increase in ambient temperature was associated with fewer incubation feedings by the male. Moreover, in areas with more food available (more deciduous trees), females had shorter incubation recesses and males fed females less often. Additionally, males fed young females more, presumably to increase such females' investment in their eggs, which were colder on average (despite the length of recesses and female nest attentiveness being independent of female age). Male age did not affect incubation feeding rate. In conclusion, the patterns of incubation behaviour were related to both environmental and individual characteristics, and male incubation feeding was adjusted to females' need for food according these characteristics, which can facilitate new insights to the study of avian incubation energetics. Parents often invest a substantial amount of energy in raising offspring. How much they do so depends on several environmental factors and on the extent they cooperate to raise the offspring. In birds, males can feed incubating females, which may allow females to stay longer on the nest, which, in turn, may ultimately improve reproductive success. The interplay between environmental factors and such incubation feeding on incubation attendance has, however, received little attention. Here, we show that favourable circumstances (higher ambient temperature and food availability) allowed incubating blue tit females to increase the time off the nest to improve self-maintenance and males to feed them less, whereas males also fed inexperienced partners more often. Thus, we show a concerted effect of several environmental and intrinsic factors on parental effort during incubation, which will help to improve the general understanding of avian incubation and parental care.

Leptin signaling is required for adaptive changes in food intake, but not energy expenditure, in response to different thermal conditions.

PubMed

Kaiyala, Karl J; Ogimoto, Kayoko; Nelson, Jarrell T; Schwartz, Michael W; Morton, Gregory J

2015-01-01

Survival of free-living animals depends on the ability to maintain core body temperature in the face of rapid and dramatic changes in their thermal environment. If food intake is not adjusted to meet the changing energy demands associated with changes of ambient temperature, a serious challenge to body energy stores can occur. To more fully understand the coupling of thermoregulation to energy homeostasis in normal animals and to investigate the role of the adipose hormone leptin to this process, comprehensive measures of energy homeostasis and core temperature were obtained in leptin-deficient ob/ob mice and their wild-type (WT) littermate controls when housed under cool (14°C), usual (22°C) or ∼ thermoneutral (30°C) conditions. Our findings extend previous evidence that WT mice robustly defend normothermia in response to either a lowering (14°C) or an increase (30°C) of ambient temperature without changes in body weight or body composition. In contrast, leptin-deficient, ob/ob mice fail to defend normothermia at ambient temperatures lower than thermoneutrality and exhibit marked losses of both body fat and lean mass when exposed to cooler environments (14°C). Our findings further demonstrate a strong inverse relationship between ambient temperature and energy expenditure in WT mice, a relationship that is preserved in ob/ob mice. However, thermal conductance analysis indicates defective heat retention in ob/ob mice, irrespective of temperature. While a negative relationship between ambient temperature and energy intake also exists in WT mice, this relationship is disrupted in ob/ob mice. Thus, to meet the thermoregulatory demands of different ambient temperatures, leptin signaling is required for adaptive changes in both energy intake and thermal conductance. A better understanding of the mechanisms coupling thermoregulation to energy homeostasis may lead to the development of new approaches for the treatment of obesity.

Leptin Signaling Is Required for Adaptive Changes in Food Intake, but Not Energy Expenditure, in Response to Different Thermal Conditions

PubMed Central

Kaiyala, Karl J.; Ogimoto, Kayoko; Nelson, Jarrell T.; Schwartz, Michael W.; Morton, Gregory J.

2015-01-01

Survival of free-living animals depends on the ability to maintain core body temperature in the face of rapid and dramatic changes in their thermal environment. If food intake is not adjusted to meet the changing energy demands associated with changes of ambient temperature, a serious challenge to body energy stores can occur. To more fully understand the coupling of thermoregulation to energy homeostasis in normal animals and to investigate the role of the adipose hormone leptin to this process, comprehensive measures of energy homeostasis and core temperature were obtained in leptin-deficient ob/ob mice and their wild-type (WT) littermate controls when housed under cool (14°C), usual (22°C) or ∼ thermoneutral (30°C) conditions. Our findings extend previous evidence that WT mice robustly defend normothermia in response to either a lowering (14°C) or an increase (30°C) of ambient temperature without changes in body weight or body composition. In contrast, leptin-deficient, ob/ob mice fail to defend normothermia at ambient temperatures lower than thermoneutrality and exhibit marked losses of both body fat and lean mass when exposed to cooler environments (14°C). Our findings further demonstrate a strong inverse relationship between ambient temperature and energy expenditure in WT mice, a relationship that is preserved in ob/ob mice. However, thermal conductance analysis indicates defective heat retention in ob/ob mice, irrespective of temperature. While a negative relationship between ambient temperature and energy intake also exists in WT mice, this relationship is disrupted in ob/ob mice. Thus, to meet the thermoregulatory demands of different ambient temperatures, leptin signaling is required for adaptive changes in both energy intake and thermal conductance. A better understanding of the mechanisms coupling thermoregulation to energy homeostasis may lead to the development of new approaches for the treatment of obesity. PMID:25756181

Sensor Amplifier for the Venus Ground Ambient

NASA Technical Reports Server (NTRS)

DelCastillo, Linda Y.; Johnson, Travis W.; Hatake, Toshiro; Mojarradi, Mohammad M.; Kolawa, Elizabeth A.

2006-01-01

Previous Venus Landers employed high temperature pressure vessels, with thermally protected electronics, to achieve successful missions, with a maximum surface lifetime of 127 minutes. Extending the operating range of electronic systems to the temperatures (480 C) and pressures (90 bar) of the Venus ground ambient would significantly increase the science return of future missions. Toward that end, the current work describes the innovative design of a sensor preamplifier, capable of working in the Venus ground ambient and designed using commercial components (thermionic vacuum tubes, wide band gap transistors, thick film resistors, advanced high temperature capacitors, and monometallic interfaces) To identify commercial components and electronic packaging materials that are capable of operation within the specified environment, a series of active devices, passive components, and packaging materials were screened for operability at 500C, assuming a 10x increase in the mission lifetime. In addition. component degradation as a function of time at 500(deg)C was evaluated. Based on the results of these preliminary evaluations, two amplifiers were developed.

The effect of climate variability on urinary stone attacks: increased incidence associated with temperature over 18 °C: a population-based study.

PubMed

Park, Hyoung Keun; Bae, Sang Rak; Kim, Satbyul E; Choi, Woo Suk; Paick, Sung Hyun; Ho, Kim; Kim, Hyeong Gon; Lho, Yong Soo

2015-02-01

The aim of this study was to evaluate the effect of seasonal variation and climate parameters on urinary tract stone attack and investigate whether stone attack is increased sharply at a specific point. Nationwide data of total urinary tract stone attack numbers per month between January 2006 and December 2010 were obtained from the Korean Health Insurance Review and Assessment Service. The effects of climatic factors on monthly urinary stone attack were assessed using auto-regressive integrated moving average (ARIMA) regression method. A total of 1,702,913 stone attack cases were identified. Mean monthly and monthly average daily urinary stone attack cases were 28,382 ± 2,760 and 933 ± 85, respectively. The stone attack showed seasonal trends of sharp incline in June, a peak plateau from July to September, and a sharp decline after September. The correlation analysis showed that ambient temperature (r = 0.557, p < 0.001) and relative humidity (r = 0.513, p < 0.001) were significantly associated with urinary stone attack cases. However, after adjustment for trends and seasonality, ambient temperature was the only climate factor associated with the stone attack cases in ARIMA regression test (p = 0.04). Threshold temperature was estimated as 18.4 °C. Risk of urinary stone attack significantly increases 1.71% (1.02-2.41 %, 95% confidence intervals) with a 1 °C increase of ambient temperature above the threshold point. In conclusion, monthly urinary stone attack cases were changed according to seasonal variation. Among the climates variables, only temperature had consistent association with stone attack and when the temperature is over 18.4 °C, urinary stone attack would be increased sharply.

Effects of cold temperature and ethanol content on VOC ...

EPA Pesticide Factsheets

Emissions of speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs), were measured in vehicle exhaust from three light-duty spark ignition vehicles operating on summer and winter grade gasoline (E0) and ethanol blended (E10 and E85) fuels. Vehicle testing was conducted using a three-phase LA92 driving cycle in a temperature-controlled chassis dynamometer at two ambient temperatures (-7 °C and 24 °C). The cold start phase and cold ambient temperature increased VOC and MSAT emissions dramatically by up to several orders of magnitude compared to emissions during other phases and warm ambient temperature testing, respectively. As a result, calculated ozone formation potentials during the cold starts were significantly higher during cold temperature tests by 7 to 21 times the warm temperature values. The use of E85 fuel generally led to substantial reductions in hydrocarbons and increases in oxygenates such as ethanol and acetaldehyde compared to E0 and E10 fuels. However, the VOC emissions from E0 and E10 fuels were not significantly different. Cold temperature effects on cold start MSAT emissions varied by individual MSAT compound, but were consistent over a range of modern spark ignition vehicles. This manuscript communicates APPCD research activities on air toxics VOC emissions from mobile sources from the EPAct dynamometer study. Speciated VOC emissions from light-duty vehicles running on gasoline and ethanol blends at cold tem

High-Pressure High-Temperature Phase Diagram of the Organic Crystal Paracetamol

NASA Astrophysics Data System (ADS)

Smith, Spencer; Montgomery, Jeffrey; Vohra, Yogesh

High-pressure high-temperature (HPHT) Raman spectroscopy studies have been performed on the organic crystal paracetamol in a diamond anvil cell utilizing boron-doped diamond as heating anvil. The HPHT data obtained from boron-doped diamond heater is cross-checked with data obtained using a standard block heater diamond anvil cell. Isobaric measurements were conducted at pressures up to 8.5 GPa and temperature up to 520 K in a number of different experiments. Solid state phase transitions from monoclinic Form I --> orthorhombic Form II were observed at various pressures and temperatures as well as transitions from Form II --> unknown Form IV. The melting temperature for paracetamol was observed to increase with increasing pressures to 8.5 GPa. Our previous angle dispersive x-ray diffraction studies at the Advanced Photon Source has confirmed the existence of two unknown crystal structures Form IV and Form V of paracetamol at high pressure and ambient temperature. The phase transformation from Form II to Form IV occurs at ~8.5 GPa and from Form IV to Form V occurs at ~11 GPa at ambient temperature. Our new data is combined with the previous ambient temperature high-pressure Raman and X- ray diffraction data to create the first HPHT phase diagram of paracetamol. Doe-NNSA Carnegie DOE Alliance Center (CDAC) under Grant Number DE-NA0002006.

Higher fine particulate matter and temperature levels impair exercise capacity in cardiac patients.

PubMed

Giorgini, Paolo; Rubenfire, Melvyn; Das, Ritabrata; Gracik, Theresa; Wang, Lu; Morishita, Masako; Bard, Robert L; Jackson, Elizabeth A; Fitzner, Craig A; Ferri, Claudio; Brook, Robert D

2015-08-01

Fine particulate matter (PM2.5) air pollution and variations in ambient temperature have been linked to increased cardiovascular morbidity and mortality. However, no large-scale study has assessed their effects on directly measured aerobic functional capacity among high-risk patients. Using a cross-sectional observational design, we evaluated the effects of ambient PM2.5 and temperature levels over 7 days on cardiopulmonary exercise test results performed among 2078 patients enrolling into a cardiac rehabilitation programme at the University of Michigan (from January 2003 to August 2011) using multiple linear regression analyses (controlling for age, sex, body mass index). Peak exercise oxygen consumption was significantly decreased by approximately 14.9% per 10 μg/m(3) increase in ambient PM2.5 levels (median 10.7 μg/m(3), IQR 10.1 μg/m(3)) (lag days 6-7). Elevations in PM2.5 were also related to decreases in ventilatory threshold (lag days 5-7) and peak heart rate (lag days 2-3) and increases in peak systolic blood pressure (lag days 4-5). A 10°C increase in temperature (median 10.5°C, IQR 17.5°C) was associated with reductions in peak exercise oxygen consumption (20.6-27.3%) and ventilatory threshold (22.9-29.2%) during all 7 lag days. In models including both factors, the outcome associations with PM2.5 were attenuated whereas the effects of temperature remained significant. Short-term elevations in ambient PM2.5, even at low concentrations within current air quality standards, and/or higher temperatures were associated with detrimental changes in aerobic exercise capacity, which can be linked to a worse quality of life and cardiovascular prognosis among cardiac rehabilitation patients. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Pressure-Drop Considerations in the Characterization of Dew-Point Transfer Standards at High Temperatures

NASA Astrophysics Data System (ADS)

Mitter, H.; Böse, N.; Benyon, R.; Vicente, T.

2012-09-01

During calibration of precision optical dew-point hygrometers (DPHs), it is usually necessary to take into account the pressure drop induced by the gas flow between the "point of reference" and the "point of use" (mirror or measuring head of the DPH) either as a correction of the reference dew-point temperature or as part of the uncertainty estimation. At dew-point temperatures in the range of ambient temperature and below, it is sufficient to determine the pressure drop for the required gas flow, and to keep the volumetric flow constant during the measurements. In this case, it is feasible to keep the dry-gas flow into the dew-point generator constant or to measure the flow downstream the DPH at ambient temperature. In normal operation, at least one DPH in addition to the monitoring DPH are used, and this operation has to be applied to each instrument. The situation is different at high dew-point temperatures up to 95 °C, the currently achievable upper limit reported in this paper. With increasing dew-point temperatures, the reference gas contains increasing amounts of water vapour and a constant dry-gas flow will lead to a significant enhanced volume flow at the conditions at the point of use, and therefore, to a significantly varying pressure drop depending on the applied dew-point temperature. At dew-point temperatures above ambient temperature, it is also necessary to heat the reference gas and the mirror head of the DPH sufficiently to avoid condensation which will additionally increase the volume flow and the pressure drop. In this paper, a method is provided to calculate the dry-gas flow rate needed to maintain a known wet-gas flow rate through a chilled mirror for a range of temperature and pressures.

Antioxidant compounds of kiwifruit during post-ripening process at ambient temperature

NASA Astrophysics Data System (ADS)

Liang, D.; Lv, X. L.; Wang, J.; Xia, H.; Xie, Y.; Li, M. Z.; Wang, Y. Z.

2017-09-01

Kiwifruit is well-known for an excellent source of antioxidants. In this study, contents of total phenolics (TPC), total flavonoids (TFC), total flavanols (TFAC) and vitamin C were investigated in different fruit tissues during post-ripening process at ambient temperature. The results explored that TPC and TFC showed declining trend with the increase in storage interval in different tissues. TFAC raised with the increase in storage interval in different fruit tissues, while was followed a decrease in later process. Vitamin C content was stable in outer and inner pericarp in prometaphase of post-ripening.

Current and Potential Future Seasonal Trends of Indoor Dwelling Temperature and Likely Health Risks in Rural Southern Africa.

PubMed

Kapwata, Thandi; Gebreslasie, Michael T; Mathee, Angela; Wright, Caradee Yael

2018-05-10

Climate change has resulted in rising temperature trends which have been associated with changes in temperature extremes globally. Attendees of Conference of the Parties (COP) 21 agreed to strive to limit the rise in global average temperatures to below 2 °C compared to industrial conditions, the target being 1.5 °C. However, current research suggests that the African region will be subjected to more intense heat extremes over a shorter time period, with projections predicting increases of 4⁻6 °C for the period 2071⁻2100, in annual average maximum temperatures for southern Africa. Increased temperatures may exacerbate existing chronic ill health conditions such as cardiovascular disease, respiratory disease, cerebrovascular disease, and diabetes-related conditions. Exposure to extreme temperatures has also been associated with mortality. This study aimed to consider the relationship between temperatures in indoor and outdoor environments in a rural residential setting in a current climate and warmer predicted future climate. Temperature and humidity measurements were collected hourly in 406 homes in summer and spring and at two-hour intervals in 98 homes in winter. Ambient temperature, humidity and windspeed were obtained from the nearest weather station. Regression models were used to identify predictors of indoor apparent temperature (AT) and to estimate future indoor AT using projected ambient temperatures. Ambient temperatures will increase by a mean of 4.6 °C for the period 2088⁻2099. Warming in winter was projected to be greater than warming in summer and spring. The number of days during which indoor AT will be categorized as potentially harmful will increase in the future. Understanding current and future heat-related health effects is key in developing an effective surveillance system. The observations of this study can be used to inform the development and implementation of policies and practices around heat and health especially in rural areas of South Africa.

Temperature influence on the development and loss of seawater tolerance in two fast-growing strains of Atlantic salmon

USGS Publications Warehouse

Handeland, S.O.; Wilkinson, E.; Sveinsbo, B.; McCormick, S.D.; Stefansson, S.O.

2004-01-01

Development of hypo-osmoregulatory ability, gill Na+,K +-ATPase activity, condition factor and growth in Atlantic salmon during parr-smolt transformation was studied in a 2??3 factorial design with three temperatures (12.0, 8.9??C and ambient, 2.4-11.9??C, mean: 6.0??C) and two farmed strains of smolts (Mowi and AquaGen). The development of hypo-osmoregulatory ability and gill Na+,K+-ATPase activity were significantly influenced by freshwater temperature. In smolts raised at 12.0??C, maximum gill Na+,K+-ATPase activity was reached in late April, compared with late May and mid-June in the 8.9??C and ambient groups, respectively. In all groups, peak gill Na+,K +-ATPase activity was seen 350 degree days (d??C) after the onset of the smolt-related increase in enzyme activity (30 March) The period of high enzyme activity (>90% of maximum) lasted approximately 250 d??C. No distinct peak level in gill Na+,K+-ATPase activity was seen in the AquaGen strain at ambient temperature. Elevated temperatures also accelerated the loss of hypo-osmoregulatory capacity. In all groups, gill Na+,K+-ATPase activity reached pre-smolt levels approximately 500 d??C after the calculated peak level. Growth rate in freshwater was influenced by strain, temperature and their interaction, with the Mowi strain showing a higher growth rate than the AquaGen strain at 8.9??C and ambient temperatures. Following transfer to seawater, a higher growth rate was recorded in smolts from the Mowi strain than the AquaGen strain from the ambient temperature regime. Temperature influences the development and loss of smolt characteristics in both strains, and has long-term effects on post-smolt performance in seawater. ?? 2004 Elsevier B.V. All rights reserved.

The association of ambient temperature with incidence of cardiac arrhythmias in a short timescale

NASA Astrophysics Data System (ADS)

Kim, Jayeun; Kim, Ho

2017-11-01

The body response time and an association between the exposure to outdoor temperature and cardiac arrhythmia were not fully understood. Hence, we further investigated the association between ambient temperature and the exacerbations of arrhythmia symptoms on a short timescale using the emergency department (ED) visit data. We used a total of 17,088 arrhythmia-related ED visits in Seoul, from 2008 to 2011 and fitted the model adjusting for other meteorological variables and air pollutants under the case-crossover analysis with the same year-month time stratification. The association was presented as an odds ratio (OR) with a 95% confidence interval (CI) by a 5 °C decrease in the ambient temperature. The delay time (h) between exposure and the onset of arrhythmia exacerbation was considered with time blocks for every 3 h as 1-3 h, up to 118-120 h; and daily lags (1 day), from 25-48 h to 97-120 h, as a multi-time average of exposures. The overall association was increased at lag 4-6 h and the increased association was statistically significant at lag 40-42 h (OR 1.027, 95% CI 1.003-1.051) and the adverse association continued at 97-120 h (OR 1.053, 95% CI 1.027-1.080). However, the delay of several days between ambient temperature and body response should be further investigated considering the modification according to varied demographic characteristics or different environmental circumstances.

Fecal Immunochemical Test (FIT) for Colon Cancer Screening: Variable Performance with Ambient Temperature

PubMed Central

Doubeni, Chyke A.; Jensen, Christopher D.; Fedewa, Stacey A.; Quinn, Virginia P.; Zauber, Ann G.; Schottinger, Joanne E.; Corley, Douglas A.; Levin, Theodore R.

2017-01-01

Introduction Fecal immunochemical tests (FITs) are widely used in colorectal cancer (CRC) screening, but hemoglobin degradation, due to exposure of the collected sample to high temperatures, could reduce test sensitivity. We examined the relation of ambient temperature exposure with FIT positivity rate and sensitivity. Methods This was a retrospective cohort study of patients 50 to 75 years in Kaiser Permanente Northern California’s CRC screening program, which began mailing FIT kits annually to screen-eligible members in 2007. Primary outcomes were FIT positivity rate and sensitivity to detect CRC. Predictors were month, season, and daily ambient temperatures of test result dates based on US National Oceanic and Atmospheric Administration data. Results Patients (n =472,542) completed 1,141,162 FITs. Weekly test positivity rate ranged from 2.6% to 8.0% (median, 4.4%) and varied significantly by month (June/July vs December/January rate ratio [RR] =0.79, 95% confidence interval [CI], 0.76 to 0.83) and season. FIT sensitivity was lower in June/July (74.5%; 95% CI, 72.5 to 76.6) than January/December (78.9%; 95% CI, 77.0 to 80.7). Conclusions FITs completed during high ambient temperatures had lower positivity rates and lower sensitivity. Changing kit design, specimen transportation practices, or avoiding periods of high ambient temperatures may help optimize FIT performance, but may also increase testing complexity and reduce patient adherence, requiring careful study. PMID:28076249

Effect of sodium bicarbonate supplementation on carcass characteristics of lambs fed concentrate diets at different ambient temperature levels.

PubMed

Jallow, Demba B; Hsia, Liang Chou

2014-08-01

The objective of this study was to investigate the influence of ambient temperatures on carcass characteristics of lambs fed concentrate diets with or without NaHCO3 supplementation. A slaughter study was carried on 12 male Black Belly Barbados lambs randomly drawn from a growth trial (35 weeks). The lambs were divided into four equal groups and allotted in a 2×2 factorial design. The lambs were allotted at random to two dietary treatments of a basal diet (35:65 roughage:concentrate) or basal diet supplemented with 4% NaHCO3 at different ambient temperatures (20°C and 30°C) in an environment controlled chamber for 10 days. Lambs were slaughtered for carcass evaluation at about 262 days of age (245 days of growth trial, 7 days adaptation and 10 days of experimental period). Ambient temperature had significant (p<0.05, p<0.05, p<0.01, and p<0.001) effects on meat color from the ribeye area (REA), fat, leg and longissimus dorsi muscles with higher values recorded for lambs in the lower temperature group than those from the higher ambient temperature group. Significant differences (p<0.05) in shear force value (kg/cm(2)) recorded on the leg muscles showed higher values (5.32 vs 4.16) in lambs under the lower ambient temperature group compared to the other group. Dietary treatments had significant (p<0.01, p<0.01, and p<0.05) effects on meat color from the REA, fat, and REA fat depth (cm(2)) with higher values recorded for lambs in the NaHCO3 supplementation group than the non supplemented group. Similarly, dietary treatments had significant differences (p<0.05) in shear force value (kg/cm(2)) of the leg muscles with the NaHCO3 groups recording higher (5.30 vs 4.60) values than those from the other group. Neither ambient temperature nor dietary treatments had any significant (p>0.05) effects on pH, and water holding capacity on both muscles. These results indicated that NaHCO3 supplementation at low ambient temperatures had caused an increase in carcass characteristics leading to significant effect on meat quality.

Projecting future summer mortality due to ambient ozone concentration and temperature changes

NASA Astrophysics Data System (ADS)

Lee, Jae Young; Lee, Soo Hyun; Hong, Sung-Chul; Kim, Ho

2017-05-01

Climate change is known to affect the human health both directly by increased heat stress and indirectly by altering environments, particularly by altering the rate of ambient ozone formation in the atmosphere. Thus, the risks of climate change may be underestimated if the effects of both future temperature and ambient ozone concentrations are not considered. This study presents a projection of future summer non-accidental mortality in seven major cities of South Korea during the 2020s (2016-2025) and 2050s (2046-2055) considering changes in temperature and ozone concentration, which were predicted by using the HadGEM3-RA model and Integrated Climate and Air Quality Modeling System, respectively. Four Representative Concentration Pathway (RCP) scenarios (RCP 2.6, 4.5, 6.0, and 8.5) were considered. The result shows that non-accidental summer mortality will increase by 0.5%, 0.0%, 0.4%, and 0.4% in the 2020s, 1.9%, 1.5%, 1.2%, and 4.4% in the 2050s due to temperature change compared to the baseline mortality during 2001-2010, under RCP 2.6, 4.5, 6.0, and 8.5, respectively, whereas the mortality will increase by 0.0%, 0.5%, 0.0%, and 0.5% in the 2020s, and 0.2%, 0.2%, 0.4%, and 0.6% in the 2050s due to ozone concentration change. The projection result shows that the future summer morality in South Korea is increased due to changes in both temperature and ozone, and the magnitude of ozone-related increase is much smaller than that of temperature-related increase, especially in the 2050s.

Ambient temperature and neck EMG with +Gz loading on a trampoline.

PubMed

Sovelius, Roope; Oksa, Juha; Rintala, Harri; Huhtala, Heini; Siitonen, Simo

2007-06-01

Fighter pilots who are frequently exposed to severe cold ambient temperatures experience neck pain disabilities and occupational disorders more often than those who are not so exposed. We hypothesized that a cold-induced increase in muscle strain might lead to in-flight neck injuries. The aims of this study were to measure the level of cooling before takeoff and to determine muscle strain under Gz loading (0 to +4 Gz) at different temperatures. Test subjects' (n = 14) skin temperature (T(skin)) over the trapezoids was measured before the walk to the aircraft and again in the cockpit (air temperature -14 degrees C). The subjects then performed trampoline exercises in two different ambient temperatures (-2 degrees C and +21 degrees C) after a 30-min period at the respective temperatures. EMG activity of the sternocleidomastoid (SCM), cervical erector spinae (CES), trapezoid (TRA), thoracic erector spinae (TES) muscles, and Tskin of the SCM and TRA were measured. Tskin over the trapezoids decreased from 30.1 +/- 1.7 degrees C to 27.8 +/- 2.6 degrees C (p < 0.001) before takeoff. The change of muscle strain in cold was +11.0% in SCM, +14.9% in CES, +3.7% in TRA, and -1.7% in TES. Change was statistically significant in the cervical, uncovered area (SCM, CES). The linear regression model indicated a 2.6% increase in muscle strain per every decreased degree centigrade in skin temperature over the SCM. Superficial cooling over the neck muscles was significant prior to takeoff. Muscle loading in the cold caused higher EMG activity. A major increase in muscle strain was seen in the cervical muscles. These findings suggest a cold-induced increase in muscle strain during in-flight Gz loading.

Warming and Acidification Induced Mass Mortality of a Coastal Keystone predator

NASA Astrophysics Data System (ADS)

Melzner, F.; Findeisen, U.

2016-02-01

The Baltic Sea is characterized by low salinity and pronounced fluctuations in pCO2. On-line monitoring of pCO2 in 2014 in Kiel Fjord demonstrated occurrence of peak values of >2,000 µatm in summer and autumn and average values >750 µatm. We assessed the impacts of elevated temperature (ambient temperature, ambient +3°C) and pCO2 (500, 1,500, 2,400 µatm) on the keystone species Asterias rubens in a fully crossed long - term experiment (N=5 replicate tanks each, 1 year duration). During spring and early summer (February - June), high temperature animals ingested significantly more food and spawned significantly earlier (April 30th) than ambient acclimated animals (May 23rd). Elevated pCO2 led to comparatively minor reductions in food intake and scope for growth during that period. During summer (June - August), elevated temperature >25°C caused negative energy budgets and >95% mortality in the warm acclimated groups, while mortality was low in the ambient temperature groups. Our results indicate that A. rubens may benefit from increased temperature during colder months, yet dramatically suffer during summer heat waves in warm years. Meaningful experimental approaches to assess species vulnerability to climate change need to encompass all seasons and realistic abiotic stressor levels.

Impacts of ambient temperature on the burden of bacillary dysentery in urban and rural Hefei, China.

PubMed

Cheng, J; Xie, M Y; Zhao, K F; Wu, J J; Xu, Z W; Song, J; Zhao, D S; Li, K S; Wang, X; Yang, H H; Wen, L Y; Su, H; Tong, S L

2017-06-01

Bacillary dysentery continues to be a major health issue in developing countries and ambient temperature is a possible environmental determinant. However, evidence about the risk of bacillary dysentery attributable to ambient temperature under climate change scenarios is scarce. We examined the attributable fraction (AF) of temperature-related bacillary dysentery in urban and rural Hefei, China during 2006-2012 and projected its shifting pattern under climate change scenarios using a distributed lag non-linear model. The risk of bacillary dysentery increased with the temperature rise above a threshold (18·4 °C), and the temperature effects appeared to be acute. The proportion of bacillary dysentery attributable to hot temperatures was 18·74% (95 empirical confidence interval (eCI): 8·36-27·44%). Apparent difference of AF was observed between urban and rural areas, with AF varying from 26·87% (95% eCI 16·21-36·68%) in urban area to -1·90% (95 eCI -25·03 to 16·05%) in rural area. Under the climate change scenarios alone (1-4 °C rise), the AF from extreme hot temperatures (>31·2 °C) would rise greatly accompanied by the relatively stable AF from moderate hot temperatures (18·4-31·2 °C). If climate change proceeds, urban area may be more likely to suffer from rapidly increasing burden of disease from extreme hot temperatures in the absence of effective mitigation and adaptation strategies.

Experimental and Theoretical Investigations on the Nanoscale Kinetic Friction in Ambient Environmental Conditions.

PubMed

Gueye, Birahima; Zhang, Yan; Wang, Yujuan; Chen, Yunfei

2015-07-08

The liquid lubrication, thermolubricity and dynamic lubricity due to mechanical oscillations are investigated with an atomic force microscope in ambient environmental conditions with different relative humidity (RH) levels. Experimental results demonstrate that high humidity at low-temperature regime enhances the liquid lubricity while at high-temperature regime it hinders the effect of the thermolubricity due to the formation of liquid bridges. Friction response to the dynamic lubricity in both high- and low-temperature regimes keeps the same trends, namely the friction force decreases with increasing the amplitude of the applied vibration on the tip regardless of the RH levels. An interesting finding is that for the dynamic lubricity at high temperature, high-humidity condition leads to the friction forces higher than that at low-humidity condition while at low temperature the opposite trend is observed. An extended two-dimensional dynamic model accounting for the RH is proposed to interpret the frictional mechanism in ambient conditions.

Evaluation of the Impact of Ambient Temperatures on Occupational Injuries in Spain.

PubMed

Martínez-Solanas, Èrica; López-Ruiz, María; Wellenius, Gregory A; Gasparrini, Antonio; Sunyer, Jordi; Benavides, Fernando G; Basagaña, Xavier

2018-06-01

Extreme cold and heat have been linked to an increased risk of occupational injuries. However, the evidence is still limited to a small number of studies of people with relatively few injuries and with a limited geographic extent, and the corresponding economic effect has not been studied in detail. We assessed the relationship between ambient temperatures and occupational injuries in Spain along with its economic effect. The daily number of occupational injuries that caused at least one day of leave and the daily maximum temperature were obtained for each Spanish province for the years 1994-2013. We estimated temperature-injuries associations with distributed lag nonlinear models, and then pooled the results using a multivariate meta-regression model. We calculated the number of injuries attributable to cold and heat, the corresponding workdays lost, and the resulting economic effect. The study included 15,992,310 occupational injuries. Overall, 2.72% [95% confidence interval (CI): 2.44-2.97] of all occupational injuries were attributed to nonoptimal ambient temperatures, with moderate heat accounting for the highest fraction. This finding corresponds to an estimated 0.67 million (95% CI: 0.60-0.73) person-days of work lost every year in Spain due to temperature, or an annual average of 42 d per 1,000 workers. The estimated annual economic burden is €370 million, or 0.03% of Spain's GDP (€2,015). Our findings suggest that extreme ambient temperatures increased the risk of occupational injuries, with substantial estimated health and economic costs. These results call for public health interventions to protect workers in the context of climate change. https://doi.org/10.1289/EHP2590.

Seasonal variation in respiration of 1-year-old shoots of scots pine exposed to elevated carbon dioxide and temperature for 4 years.

PubMed

Zha, T S; Kellomaki, S; Wang, K Y

2003-07-01

Sixteen 20-year-old Scots pine (Pinus sylvestris L.) trees growing in the field were enclosed for 4 years in environment-controlled chambers that maintained: (1) ambient conditions (CON); (2) elevated atmospheric CO2 concentration (ambient + 350 micro mol mol-1; EC); (3) elevated temperature (ambient +2-6 degrees C; ET); or (4) elevated CO2 and elevated temperature (ECT). The dark respiration rates of 1-year-old shoots, from which needles had been partly removed, were measured over the growing season in the fourth year. In all treatments, the temperature coefficient of respiration, Q10, changed with season, being smaller during the growing season than at other times. Respiration rate varied diurnally and seasonally with temperature, being highest around mid-summer and declining gradually thereafter. When measurements were made at the temperature of the chamber, respiration rates were reduced by the EC treatment relative to CON, but were increased by ET and ECT treatments. However, respiration rates at a reference temperature of 15 degrees C were reduced by ET and ECT treatments, reflecting a decreased capacity for respiration at warmer temperatures (negative acclimation). The interaction between season and treatment was not significant. Growth respiration did not differ between treatments, but maintenance respiration did, and the differences in mean daily respiration rate between the treatments were attributable to the maintenance component. We conclude that maintenance respiration should be considered when modelling respiratory responses to elevated CO2 and elevated temperature, and that increased atmospheric temperature is more important than increasing CO2 when assessing the carbon budget of pine forests under conditions of climate change.

Increasing ambient temperature reduces emotional well-being.

PubMed

Noelke, Clemens; McGovern, Mark; Corsi, Daniel J; Jimenez, Marcia P; Stern, Ari; Wing, Ian Sue; Berkman, Lisa

2016-11-01

This study examines the impact of ambient temperature on emotional well-being in the U.S. population aged 18+. The U.S. is an interesting test case because of its resources, technology and variation in climate across different areas, which also allows us to examine whether adaptation to different climates could weaken or even eliminate the impact of heat on well-being. Using survey responses from 1.9 million Americans over the period from 2008 to 2013, we estimate the effect of temperature on well-being from exogenous day-to-day temperature variation within respondents' area of residence and test whether this effect varies across areas with different climates. We find that increasing temperatures significantly reduce well-being. Compared to average daily temperatures in the 50-60°F (10-16°C) range, temperatures above 70°F (21°C) reduce positive emotions (e.g. joy, happiness), increase negative emotions (e.g. stress, anger), and increase fatigue (feeling tired, low energy). These effects are particularly strong among less educated and older Americans. However, there is no consistent evidence that heat effects on well-being differ across areas with mild and hot summers, suggesting limited variation in heat adaptation. Copyright © 2016 Elsevier Inc. All rights reserved.

The effect of heat waves, elevated [CO2 ] and low soil water availability on northern red oak (Quercus rubra L.) seedlings.

PubMed

Bauweraerts, Ingvar; Wertin, Timothy M; Ameye, Maarten; McGuire, Mary Anne; Teskey, Robert O; Steppe, Kathy

2013-02-01

The frequency and intensity of heat waves are predicted to increase. This study investigates whether heat waves would have the same impact as a constant increase in temperature with the same heat sum, and whether there would be any interactive effects of elevated [CO2 ] and soil moisture content. We grew Quercus rubra seedlings in treatment chambers maintained at either ambient or elevated [CO2 ] (380 or 700 μmol CO2 mol(-1) ) with temperature treatments of ambient, ambient +3 °C, moderate heat wave (+6 °C every other week) or severe heat wave (+12 °C every fourth week) temperatures. Averaged over a 4-week period, and the entire growing season, the three elevated temperature treatments had the same average temperature and heat sum. Half the seedlings were watered to a soil water content near field capacity, half to about 50% of this value. Foliar gas exchange measurements were performed morning and afternoon (9:00 and 15:00 hours) before, during and after an applied heat wave in August 2010. Biomass accumulation was measured after five heat wave cycles. Under ambient [CO2 ] and well-watered conditions, biomass accumulation was highest in the +3 °C treatment, intermediate in the +6 °C heat wave and lowest in the +12 °C heat wave treatment. This response was mitigated by elevated [CO2 ]. Low soil moisture significantly decreased net photosynthesis (Anet ) and biomass in all [CO2 ] and temperature treatments. The +12 °C heat wave reduced afternoon Anet by 23% in ambient [CO2 ]. Although this reduction was relatively greater under elevated [CO2 ], Anet values during this heat wave were still 34% higher than under ambient [CO2 ]. We concluded that heat waves affected biomass growth differently than the same amount of heat applied uniformly over the growing season, and that the plant response to heat waves also depends on [CO2 ] and soil moisture conditions. © 2012 Blackwell Publishing Ltd.

Response of Respiration of Soybean Leaves Grown at Ambient and Elevated Carbon Dioxide Concentrations to Day-to-day Variation in Light and Temperature under Field Conditions

PubMed Central

BUNCE, JAMES A.

2005-01-01

• Background and Aims Respiration is an important component of plant carbon balance, but it remains uncertain how respiration will respond to increases in atmospheric carbon dioxide concentration, and there are few measurements of respiration for crop plants grown at elevated [CO2] under field conditions. The hypothesis that respiration of leaves of soybeans grown at elevated [CO2] is increased is tested; and the effects of photosynthesis and acclimation to temperature examined. • Methods Net rates of carbon dioxide exchange were recorded every 10 min, 24 h per day for mature upper canopy leaves of soybeans grown in field plots at the current ambient [CO2] and at ambient plus 350 µmol mol−1 [CO2] in open top chambers. Measurements were made on pairs of leaves from both [CO2] treatments on a total of 16 d during the middle of the growing seasons of two years. • Key Results Elevated [CO2] increased daytime net carbon dioxide fixation rates per unit of leaf area by an average of 48 %, but had no effect on night-time respiration expressed per unit of area, which averaged 53 mmol m−2 d−1 (1·4 µmol m−2 s−1) for both the ambient and elevated [CO2] treatments. Leaf dry mass per unit of area was increased on average by 23 % by elevated [CO2], and respiration per unit of mass was significantly lower at elevated [CO2]. Respiration increased by a factor of 2·5 between 18 and 26 °C average night temperature, for both [CO2] treatments. • Conclusions These results do not support predictions that elevated [CO2] would increase respiration per unit of area by increasing photosynthesis or by increasing leaf mass per unit of area, nor the idea that acclimation of respiration to temperature would be rapid enough to make dark respiration insensitive to variation in temperature between nights. PMID:15781437

Yield and cold storage of Trichoderma conidia is influenced by substrate pH and storage temperature.

PubMed

Steyaert, Johanna M; Chomic, Anastasia; Nieto-Jacobo, Maria; Mendoza-Mendoza, Artemio; Hay, Amanda J; Braithwaite, Mark; Stewart, Alison

2017-05-01

In this study we examined the influence of the ambient pH during morphogenesis on conidial yield of Trichoderma sp. "atroviride B" LU132 and T. hamatum LU593 and storage at low temperatures. The ambient pH of the growth media had a dramatic influence on the level of Trichoderma conidiation and this was dependent on the strain and growth media. On malt-extract agar, LU593 yield decreased with increasing pH (3-6), whereas yield increased with increasing pH for LU132. During solid substrate production the reverse was true for LU132 whereby yield decreased with increasing pH. The germination potential of the conidia decreased significantly over time in cold storage and the rate of decline was a factor of the strain, pH during morphogenesis, growth media, and storage temperature. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of climate change on residential infiltration and air pollution exposure.

PubMed

Ilacqua, Vito; Dawson, John; Breen, Michael; Singer, Sarany; Berg, Ashley

2017-01-01

Air exchange through infiltration is driven partly by indoor/outdoor temperature differences, and as climate change increases ambient temperatures, such differences could vary considerably even with small ambient temperature increments, altering patterns of exposures to both indoor and outdoor pollutants. We calculated changes in air fluxes through infiltration for prototypical detached homes in nine metropolitan areas in the United States (Atlanta, Boston, Chicago, Houston, Los Angeles, Minneapolis, New York, Phoenix, and Seattle) from 1970-2000 to 2040-2070. The Lawrence Berkeley National Laboratory model of infiltration was used in combination with climate data from eight regionally downscaled climate models from the North American Regional Climate Change Assessment Program. Averaged over all study locations, seasons, and climate models, air exchange through infiltration would decrease by ~5%. Localized increased infiltration is expected during the summer months, up to 20-30%. Seasonal and daily variability in infiltration are also expected to increase, particularly during the summer months. Diminished infiltration in future climate scenarios may be expected to increase exposure to indoor sources of air pollution, unless these ventilation reductions are otherwise compensated. Exposure to ambient air pollution, conversely, could be mitigated by lower infiltration, although peak exposure increases during summer months should be considered, as well as other mechanisms.

Influence of fuel temperature on atomization performance of pressure-swirl atomizers

NASA Astrophysics Data System (ADS)

Wang, X. F.; Lefebvre, A. H.

The influence of fuel temperature on mean drop size and drop-size distribution is examined for aviation gasoline and diesel oil, using three pressure-swirl simplex nozzles. Spray characteristics are measured over wide ranges of fuel injection pressure and ambient air pressure using a Malvern spray analyzer. Fuel temperatures are varied from -20 C to +50 C. Over this range of temperature, the overall effect of an increase in fuel temperature is to reduce the mean drop size and broaden the distribution of drop sizes in the spray. Generally, it is found that the influence of fuel temperature on mean drop size is far more pronounced for diesel oil than for gasoline. For both fuels the beneficial effect of higher fuel temperatures on atomization quality is sensibly independent of ambient air pressure.

Advanced Catalysts for the Ambient Temperature Oxidation of Carbon Monoxide and Formaldehyde

NASA Technical Reports Server (NTRS)

Nalette, Tim; Eldridge, Christopher; Yu, Ping; Alpetkin, Gokhan; Graf, John

2010-01-01

The primary applications for ambient temperature carbon monoxide (CO) oxidation catalysts include emergency breathing masks and confined volume life support systems, such as those employed on the Shuttle. While Hopcalite is typically used in emergency breathing masks for terrestrial applications, in the 1970s, NASA selected a 2% platinum (Pt) on carbon for use on the Shuttle since it is more active and also more tolerant to water vapor. In the last 10-15 years there have been significant advances in ambient temperature CO oxidation catalysts. Langley Research Center developed a monolithic catalyst for ambient temperature CO oxidation operating under stoichiometric conditions for closed loop carbon dioxide (CO2) laser applications which is also advertised as having the potential to oxidize formaldehyde (HCHO) at ambient temperatures. In the last decade it has been discovered that appropriate sized nano-particles of gold are highly active for CO oxidation, even at sub-ambient temperatures, and as a result there has been a wealth of data reported in the literature relating to ambient/low temperature CO oxidation. In the shorter term missions where CO concentrations are typically controlled via ambient temperature oxidation catalysts, formaldehyde is also a contaminant of concern, and requires specially treated carbons such as Calgon Formasorb as untreated activated carbon has effectively no HCHO capacity. This paper examines the activity of some of the newer ambient temperature CO and formaldehyde (HCHO) oxidation catalysts, and measures the performance of the catalysts relative to the NASA baseline Ambient Temperature Catalytic Oxidizer (ATCO) catalyst at conditions of interest for closed loop trace contaminant control systems.

Elevated Temperature and CO2 Stimulate Late-Season Photosynthesis But Impair Cold Hardening in Pine.

PubMed

Chang, Christine Y; Fréchette, Emmanuelle; Unda, Faride; Mansfield, Shawn D; Ensminger, Ingo

2016-10-01

Rising global temperature and CO 2 levels may sustain late-season net photosynthesis of evergreen conifers but could also impair the development of cold hardiness. Our study investigated how elevated temperature, and the combination of elevated temperature with elevated CO 2 , affected photosynthetic rates, leaf carbohydrates, freezing tolerance, and proteins involved in photosynthesis and cold hardening in Eastern white pine (Pinus strobus). We designed an experiment where control seedlings were acclimated to long photoperiod (day/night 14/10 h), warm temperature (22°C/15°C), and either ambient (400 μL L -1 ) or elevated (800 μmol mol -1 ) CO 2 , and then shifted seedlings to growth conditions with short photoperiod (8/16 h) and low temperature/ambient CO 2 (LTAC), elevated temperature/ambient CO 2 (ETAC), or elevated temperature/elevated CO 2 (ETEC). Exposure to LTAC induced down-regulation of photosynthesis, development of sustained nonphotochemical quenching, accumulation of soluble carbohydrates, expression of a 16-kD dehydrin absent under long photoperiod, and increased freezing tolerance. In ETAC seedlings, photosynthesis was not down-regulated, while accumulation of soluble carbohydrates, dehydrin expression, and freezing tolerance were impaired. ETEC seedlings revealed increased photosynthesis and improved water use efficiency but impaired dehydrin expression and freezing tolerance similar to ETAC seedlings. Sixteen-kilodalton dehydrin expression strongly correlated with increases in freezing tolerance, suggesting its involvement in the development of cold hardiness in P. strobus Our findings suggest that exposure to elevated temperature and CO 2 during autumn can delay down-regulation of photosynthesis and stimulate late-season net photosynthesis in P. strobus seedlings. However, this comes at the cost of impaired freezing tolerance. Elevated temperature and CO 2 also impaired freezing tolerance. However, unless the frequency and timing of extreme low-temperature events changes, this is unlikely to increase risk of freezing damage in P. strobus seedlings. © 2016 American Society of Plant Biologists. All Rights Reserved.

Elevated Temperature and CO2 Stimulate Late-Season Photosynthesis But Impair Cold Hardening in Pine[OPEN

PubMed Central

2016-01-01

Rising global temperature and CO2 levels may sustain late-season net photosynthesis of evergreen conifers but could also impair the development of cold hardiness. Our study investigated how elevated temperature, and the combination of elevated temperature with elevated CO2, affected photosynthetic rates, leaf carbohydrates, freezing tolerance, and proteins involved in photosynthesis and cold hardening in Eastern white pine (Pinus strobus). We designed an experiment where control seedlings were acclimated to long photoperiod (day/night 14/10 h), warm temperature (22°C/15°C), and either ambient (400 μL L−1) or elevated (800 μmol mol−1) CO2, and then shifted seedlings to growth conditions with short photoperiod (8/16 h) and low temperature/ambient CO2 (LTAC), elevated temperature/ambient CO2 (ETAC), or elevated temperature/elevated CO2 (ETEC). Exposure to LTAC induced down-regulation of photosynthesis, development of sustained nonphotochemical quenching, accumulation of soluble carbohydrates, expression of a 16-kD dehydrin absent under long photoperiod, and increased freezing tolerance. In ETAC seedlings, photosynthesis was not down-regulated, while accumulation of soluble carbohydrates, dehydrin expression, and freezing tolerance were impaired. ETEC seedlings revealed increased photosynthesis and improved water use efficiency but impaired dehydrin expression and freezing tolerance similar to ETAC seedlings. Sixteen-kilodalton dehydrin expression strongly correlated with increases in freezing tolerance, suggesting its involvement in the development of cold hardiness in P. strobus. Our findings suggest that exposure to elevated temperature and CO2 during autumn can delay down-regulation of photosynthesis and stimulate late-season net photosynthesis in P. strobus seedlings. However, this comes at the cost of impaired freezing tolerance. Elevated temperature and CO2 also impaired freezing tolerance. However, unless the frequency and timing of extreme low-temperature events changes, this is unlikely to increase risk of freezing damage in P. strobus seedlings. PMID:27591187

Nitrous oxide causes a regulated hypothermia: rats select a cooler ambient temperature while becoming hypothermic.

PubMed

Ramsay, Douglas S; Seaman, Jana; Kaiyala, Karl J

2011-04-18

An initial administration of 60% nitrous oxide (N(2)O) evokes hypothermia in rats and if the administration continues for more than 1-2h, acute tolerance typically develops such that the initial reduction in core temperature (Tc) reverses and Tc recovers toward control values. Calorimeter studies at normal ambient temperature indicate that hypothermia results from a transient reduction in heat production (HP) combined with an elevation in heat loss. Acute tolerance develops primarily due to progressive increases in HP. Our aim was to determine whether rats provided a choice of ambient temperatures would behaviorally facilitate or oppose N(2)O-induced hypothermia. A gas-tight thermally-graded alleyway (range, 6.7-37.0°C) enabled male Long-Evans rats (n=12) to select a preferred ambient temperature during a 5-hour steady-state administration of 60% N(2)O and a separate paired control gas exposure (order counterbalanced). Tc was measured telemetrically from a sensor surgically implanted into the peritoneal cavity >7days before testing. Internal LED lighting maintained the accustomed day:night cycle (light cycle 0700-1900h) during sessions lasting 45.5h. Rats entered the temperature gradient at 1100h, and the 5-h N(2)O or control gas period did not start until 23h later to provide a long habituation/training period. Food and water were provided ad libitum at the center of the alleyway. The maximum decrease of mean Tc during N(2)O administration occurred at 0.9h and was -2.05±0.25°C; this differed significantly (p<0.0001) from the corresponding Tc change at 0.9h during control gas administration (0.01±0.14°C). The maximum decrease of the mean selected ambient temperature during N(2)O administration occurred at 0.7h and was -13.58±1.61°C; this differed significantly (p<0.0001) from the corresponding mean change in the selected ambient temperature at 0.7h during control gas administration (0.30±1.49°C). N(2)O appears to induce a regulated hypothermia because the selection of a cool ambient temperature facilitates the reduction in Tc. The recovery of Tc during N(2)O administration (i.e., acute tolerance development) could have been facilitated by selection of ambient temperatures that were warmer than those chosen during control administrations, but interestingly, this did not occur. Copyright © 2011 Elsevier Inc. All rights reserved.

Nitrous Oxide Causes a Regulated Hypothermia: Rats Select a Cooler Ambient Temperature While Becoming Hypothermic

PubMed Central

Ramsay, Douglas S.; Seaman, Jana; Kaiyala, Karl J.

2011-01-01

An initial administration of 60% nitrous oxide (N2O) evokes hypothermia in rats and if the administration continues for more than 1 – 2 hours, acute tolerance typically develops such that the initial reduction in core temperature (Tc) reverses and Tc recovers toward control values. Calorimeter studies at normal ambient temperature indicate that hypothermia results from a transient reduction in heat production (HP) combined with an elevation in heat loss. Acute tolerance develops primarily due to progressive increases in HP. Our aim was to determine whether rats provided a choice of ambient temperatures would behaviorally facilitate or oppose N2O -induced hypothermia. A gas-tight thermally-graded alleyway (range, 6.7 – 37.0°C) enabled male Long-Evans rats (n=12) to select a preferred ambient temperature during a 5-hour steady-state administration of 60% N2O and a separate paired control gas exposure (order counterbalanced). Tc was measured telemetrically from a sensor surgically implanted into the peritoneal cavity > 7 days before testing. Internal LED lighting maintained the accustomed day:night cycle (light cycle 0700 – 1900 h) during sessions lasting 45.5 hours. Rats entered the temperature gradient at 1100 h, and the 5-h N2O or control gas period did not start until 23 hours later to provide a long habituation / training period. Food and water were provided ad libitum at the center of the alleyway. The maximum decrease of mean Tc during N2O administration occurred at 0.9 h and was −2.05 ± 0.25°C; this differed significantly (p<0.0001) from the corresponding Tc change at 0.9 h during control gas administration (0.01 ± 0.14°C). The maximum decrease of mean selected ambient temperature during N2O administration occurred at 0.7 h and was −13.58 ± 1.61°C; this differed significantly (p < 0.0001) from the corresponding mean change in selected ambient temperature at 0.7 h during control gas administration (0.30 ± 1.49°C). N2O appears to induce a regulated hypothermia because the selection of a cool ambient temperature facilitates the reduction in Tc. The recovery of Tc during N2O administration (i.e., acute tolerance development) could have been facilitated by selection of ambient temperatures that were warmer than those chosen during control administrations, but interestingly, this did not occur. PMID:21184766

CHANGES IN AMBIENT TEMPERATURE TRIGGER YAWNING BUT NOT STRETCHING IN RATS

PubMed Central

Gallup, Andrew C.; Miller, Ralph R.; Clark, Anne B.

2010-01-01

Yawning appears to be involved in arousal, state change, and activity across vertebrates. Recent research suggests that yawning may support effective changes in mental state or vigilance through cerebral cooling. To further investigate the relationship between yawning, state change, and thermoregulation, 12 Sprague-Dawley rats (Rattus norvegicus) were exposed to a total of two hours of ambient temperature manipulation over a period of 48 hours. Using a repeated measures design, each rat experienced a range of increasing (22→32°C), decreasing (32→22°C), and constant temperatures (22°C; 32°C). Yawning and locomotor activity occurred most frequently during initial changes in temperature, irrespective of direction, compared to more extended periods of temperature manipulation. The rate of yawning also diminished during constant high temperatures (32°C) compared to low temperatures (22°C). Unlike yawning, however, stretching was unaffected by ambient temperature variation. These findings are compared to recent work on budgerigars (Melopsittacus undulatus), and the ecological selective pressures for yawning in challenging thermal environments are discussed. The results support previous comparative research connecting yawning with arousal and state change, and contribute to refining the predictions of the thermoregulatory hypothesis across vertebrates. PMID:21132114

Raman Channel Temperature Measurement of SiC MESFET as a Function of Ambient Temperature and DC Power

NASA Technical Reports Server (NTRS)

Ponchak, George E.; Eldridge, Jeffrey J.; Krainsky, Isay L.

2009-01-01

Raman spectroscopy is used to measure the junction temperature of a Cree SiC MESFET as a function of the ambient temperature and DC power. The carrier temperature, which is approximately equal to the ambient temperature, is varied from 25 C to 450 C, and the transistor is biased with VDS=10V and IDS of 50 mA and 100 mA. It is shown that the junction temperature is approximately 52 and 100 C higher than the ambient temperature for the DC power of 500 and 1000 mW, respectively.

Superconductivity at 52.5 K in the lanthanum-barium-copper-oxide system

NASA Technical Reports Server (NTRS)

Chu, C. W.; Hor, P. H.; Meng, R. L.; Gao, L.; Huang, Z. J.

1987-01-01

The electrical properties of the (La/0/9/Ba/0.1/)CuO/4-y/ system are examined under ambient and hydrostatic pressures. The resistance, ac magnetic susceptibility, and superconductivity onset, midpoint, and intercept temperatures are measured. It is observed that at ambient pressure the resistance decreases with temperature decreases, and the ac susceptibility shows diamagnetic shifts starting at about 32 K. Under hydrostatic pressure a superconducting transition with an onset temperature of 52.5 K is observed, and the resistance increases at lower temperatures. The data reveal that the electrical properties of the La-Ba-Cu-O system are dependent on samples and preparation conditions. Various causes for the high temperature superconductivity of the system are proposed.

Impact of patient and environmental factors on capillary refill time in adults.

PubMed

Anderson, Bronwyn; Kelly, Anne-Maree; Kerr, Debra; Clooney, Megan; Jolley, Damien

2008-01-01

Capillary refill time (CRT) has been taught as a rapid indicator of circulatory status. The aim of this study was to define normal CRT in the Australian context and the environmental, patient, and drug factors that influence it. This prospective observational study included healthy adults at hospital clinics, workplaces, universities, and community groups. Volunteer participants provided their age, sex, ethnic group, and use of hypertensive or cardiac medications. Capillary refill time, ambient temperature, and patient temperature were recorded in a standard manner. Data were analyzed using descriptive statistics and regression analyses. The 95th percentile was used to define the upper limit of normal. One thousand participants were included; 57% were women, 90% were white, and 21% were taking cardiac medications. The median CRT was 1.9 seconds (95th percentile, 3.5 seconds). The CRT increased 3.3% for each additional decade of age. The CRT was also on average 7% lower in men than in women. The CRT decreased by 1.2% per degree-Celsius rise of ambient temperature, independently of patient's temperature, and decreased by 5% for each degree-Celsius rise in patient temperature, independently of ambient temperature. On multivariant analysis, age, sex, ambient temperature, and patient temperature were statistically significant predictors of CRT, but together explain only 8% of the observed variability. Capillary refill time varies with environmental and patient factors, but these account for only a small proportion of the variability observed. Its suitability as a reliable clinical test is doubtful.

Implications of High Temperature and Elevated CO2 on Flowering Time in Plants

PubMed Central

Jagadish, S. V. Krishna; Bahuguna, Rajeev N.; Djanaguiraman, Maduraimuthu; Gamuyao, Rico; Prasad, P. V. Vara; Craufurd, Peter Q.

2016-01-01

Flowering is a crucial determinant for plant reproductive success and seed-set. Increasing temperature and elevated carbon-dioxide (e[CO2]) are key climate change factors that could affect plant fitness and flowering related events. Addressing the effect of these environmental factors on flowering events such as time of day of anthesis (TOA) and flowering time (duration from germination till flowering) is critical to understand the adaptation of plants/crops to changing climate and is the major aim of this review. Increasing ambient temperature is the major climatic factor that advances flowering time in crops and other plants, with a modest effect of e[CO2].Integrated environmental stimuli such as photoperiod, temperature and e[CO2] regulating flowering time is discussed. The critical role of plant tissue temperature influencing TOA is highlighted and crop models need to substitute ambient air temperature with canopy or floral tissue temperature to improve predictions. A complex signaling network of flowering regulation with change in ambient temperature involving different transcription factors (PIF4, PIF5), flowering suppressors (HvODDSOC2, SVP, FLC) and autonomous pathway (FCA, FVE) genes, mainly from Arabidopsis, provides a promising avenue to improve our understanding of the dynamics of flowering time under changing climate. Elevated CO2 mediated changes in tissue sugar status and a direct [CO2]-driven regulatory pathway involving a key flowering gene, MOTHER OF FT AND TFL1 (MFT), are emerging evidence for the role of e[CO2] in flowering time regulation. PMID:27446143

Seasonal patterns in body temperature of free-living rock hyrax (Procavia capensis).

PubMed

Brown, Kelly J; Downs, Colleen T

2006-01-01

Rock hyrax (Procavia capensis) are faced with large daily fluctuations in ambient temperature during summer and winter. In this study, peritoneal body temperature of free-living rock hyrax was investigated. During winter, when low ambient temperatures and food supply prevail, rock hyrax maintained a lower core body temperature relative to summer. In winter body temperatures during the day were more variable than at night. This daytime variability is likely a result of body temperatures being raised from basking in the sun. Body temperatures recorded during winter never fell to low levels recorded in previous laboratory studies. During summer ambient temperatures exceeded the thermoneutral zone of the rock hyrax throughout most of the day, while crevice temperatures remained within the thermoneutral zone of rock hyrax. However, in summer variation in core body temperature was small. Minimum and maximum body temperatures did not coincide with minimum and maximum ambient temperatures. Constant body temperatures were also recorded when ambient temperatures reached lethal limits. During summer it is likely that rock hyrax select cooler refugia to escape lethal temperatures and to prevent excessive water loss. Body temperature of rock hyrax recorded in this study reflects the adaptability of this animal to the wide range of ambient temperatures experienced in its natural environment.

Physicochemical changes of 'Phulae' pineapple fruit treated with short-term anoxia during ambient storage.

PubMed

Techavuthiporn, Chairat; Boonyaritthongchai, Panida; Supabvanich, Suriyan

2017-08-01

The effects of short-term anoxia exposure for 16h on physicochemical changes of 'Phulae' pineapple fruit stored at ambient temperature (25±2°C) were investigated. The respiratory rate of the fruit was induced by the anoxia treatment. However, it retarded the increase in moisture loss and maintained both flesh and pulp colour by inhibiting polyphenol oxidase (PPO) activity of the both tissues. The anoxia exposure delayed the increase in total sugar content and enhanced total ascorbic acid content during storage. The half-cut pineapple fruit showed that the anoxia exposure completely inhibited internal transparency of the flesh tissue adjacent to core during the storage. In conclusion, the short-term anoxia exposure for 16h maintained postharvest quality, retarded physiological disorder and enhanced nutritional values of the pineapple fruit stored at ambient temperature (25±2°C). Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of CaO2 addition on anaerobic digestion of waste activated sludge at different temperatures and the promotion of valuable carbon source production under ambient condition.

PubMed

Ping, Qian; Lu, Xiao; Zheng, Ming; Li, Yongmei

2018-06-06

The effect of calcium peroxide (CaO 2 ) addition on anaerobic digestion (AD) of waste activated sludge (WAS) at different temperatures (20 °C, 35 °C, and 55 °C) were investigated. The results show that CaO 2 addition had significant positive effect on short-chain fatty acids (SCFAs) production under ambient and mesophilic conditions. Polysaccharides and proteins embedded in extracellular polymeric substances (EPS) were effectively released from inner fraction to outer fraction, and non-biodegradable humic-like substances were decreased while easily biodegradable tryptophan-like proteins increased. These effects were most remarkable under ambient conditions. However, CaO 2 addition was unfavorable to thermophilic AD because of high free ammonia concentrations and the accumulation of humic-like substances. Temperature showed a stronger effect than CaO 2 on microbial community structure, but CaO 2 addition was more effective than temperature in enhancing hydrolytic and acidifying microorganisms. Predictive functional profiling indicated that microbial hydrolysis, metabolism and acidification were promoted by CaO 2 under ambient conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Pregnancy outcome in heat-exposed hamsters; the involvement of the pineal.

PubMed

Kaplanski, J; Zohar, R; Sod-Moriah, U A; Magal, E; Hirschmann, N; Nir, I

1988-01-01

The effect of high ambient temperature (34 degrees C) on the function of the female reproductive system, on embryonic development and on outcome of pregnancy, was investigated in heat-exposed sham-operated (Sh) and pinealectomized (Px) golden hamsters maintained under short photoperiod. Plasma prolactin levels were reduced in both heat-exposed groups (ShH and PxH) but pituitary prolactin was increased in the pinealectomized groups irrespective of ambient temperature (21 or 34 degrees C). Pituitary weights and LH contents were not affected in any test group. Heat exposure brought about a reduction in the number of corpora lutea and of pups born, the latter being more drastically reduced in absence of the pineal; the depressant effect of heat on ovarian weight was evident only in the pinealectomized animals. Progesterone levels were not affected in any test group and pregnancy was not prolonged, thus, it would seem that pregnant hamsters adapt themselves well to heat. Moreover, high ambient temperature promoted a rise in pineal. HIOMT activity and boosted cortisol levels in presence of the pineal gland only, which, together with the above findings, shows that the pineal can provide protection for pregnant hamsters against adverse effects of high ambient temperature.

Impact of cold temperature on Euro 6 passenger car emissions.

PubMed

Suarez-Bertoa, Ricardo; Astorga, Covadonga

2018-03-01

Hydrocarbons, CO, NOx, NH 3 , N 2 O, CO 2 and particulate matter emissions affect air quality, global warming and human health. Transport sector is an important source of these pollutants and high pollution episodes are often experienced during the cold season. However, EU vehicle emissions regulation at cold ambient temperature only addresses hydrocarbons and CO vehicular emissions. For that reason, we have studied the impact that cold ambient temperatures have on Euro 6 diesel and spark ignition (including: gasoline, ethanol flex-fuel and hybrid vehicles) vehicle emissions using the World-harmonized Light-duty Test Cycle (WLTC) at -7 °C and 23 °C. Results indicate that when facing the WLTC at 23 °C the tested vehicles present emissions below the values set for type approval of Euro 6 vehicles (still using NEDC), with the exception of NOx emissions from diesel vehicles that were 2.3-6 times higher than Euro 6 standards. However, emissions disproportionally increased when vehicles were tested at cold ambient temperature (-7 °C). High solid particle number (SPN) emissions (>1 × 10 11 # km -1 ) were measured from gasoline direct injection (GDI) vehicles and gasoline port fuel injection vehicles. However, only diesel and GDI SPN emissions are currently regulated. Results show the need for a new, technology independent, procedure that enables the authorities to assess pollutant emissions from vehicles at cold ambient temperatures. Harmful pollutant emissions from spark ignition and diesel vehicles are strongly and negatively affected by cold ambient temperatures. Only hydrocarbon, CO emissions are currently regulated at cold temperature. Therefore, it is of great importance to revise current EU winter vehicle emissions regulation. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Models to predict both sensible and latent heat transfer in the respiratory tract of Morada Nova sheep under semiarid tropical environment

NASA Astrophysics Data System (ADS)

Fonseca, Vinícius Carvalho; Saraiva, Edilson Paes; Maia, Alex Sandro Campos; Nascimento, Carolina Cardoso Nagib; da Silva, Josinaldo Araújo; Pereira, Walter Esfraim; Filho, Edgard Cavalcanti Pimenta; Almeida, Maria Elivânia Vieira

2017-05-01

The aim of this study was to build a prediction model both sensible and latent heat transfer by respiratory tract for Morada Nova sheep under field conditions in a semiarid tropical environment, using easily measured physiological and environmental parameters. Twelve dry Morada Nova ewes with an average of 3 ± 1.2 years old and average body weight of 32.76 ± 3.72 kg were used in a Latin square design 12 × 12 (12 days of records and 12 schedules). Tidal volume, respiratory rate, expired air temperature, and partial vapor pressure of the expired air were obtained from the respiratory facial mask and using a physiological measurement system. Ewes were evaluated from 0700 to 1900 h in each day under shade. A simple nonlinear model to estimate tidal volume as a function of respiratory rate was developed. Equation to estimate the expired air temperature was built, and the ambient air temperature was the best predictor together with relative humidity and ambient vapor pressure. In naturalized Morada Nova sheep, respiratory convection seems to be a mechanism of heat transfer of minor importance even under mild air temperature. Evaporation from the respiratory system increased together with ambient air temperature. At ambient air temperature, up to 35 °C respiratory evaporation accounted 90 % of the total heat lost by respiratory system, on average. Models presented here allow to estimate the heat flow from the respiratory tract for Morada Nova sheep bred in tropical region, using easily measured physiological and environmental traits as respiratory rate, ambient air temperature, and relative humidity.

EFFECTS OF ELEVATED CO2 AND TEMPERATURE ON GROWTH, BIOCHEMISTRY AND PHYSIOLOGY OF DOUGLAS-FIR

EPA Science Inventory

We examined the interactive effects of CO2 concentration and mean annual temperature on physiology, biochemistry and growth of Douglas fir seedlings. Seedlings were grown at ambient CO2 or ambient + 200 ppm CO2 and at ambient temperature or ambient + 4 ?C. Needle gas exchange m...

A Study of Repeated Wrist Temperature of Sixth, Seventh, and Eighth Graders.

ERIC Educational Resources Information Center

Matthews, Doris B.; Quinn, Jimmy L.

While evidence exists that a person's peripheral temperature responds to his state of arousal or stress, it also responds to other environmental factors. Wrist temperature has been found to vary with ambient temperature, and to increase during the school day. Before wrist temperature can be established as a valid measure of anxiety, stress, or…

Impact of ambient temperature on children's health: a systematic review.

PubMed

Xu, Zhiwei; Etzel, Ruth A; Su, Hong; Huang, Cunrui; Guo, Yuming; Tong, Shilu

2012-08-01

Children are vulnerable to temperature extremes. This paper aimed to review the literature regarding the relationship between ambient temperature and children's health and to propose future research directions. A literature search was conducted in February 2012 using the databases including PubMed, ProQuest, ScienceDirect, Scopus and Web of Science. Empirical studies regarding the impact of ambient temperature on children's mortality and morbidity were included. The existing literature indicates that very young children, especially children under one year of age, are particularly vulnerable to heat-related deaths. Hot and cold temperatures mainly affect cases of infectious diseases among children, including gastrointestinal diseases, malaria, hand, foot and mouse disease, and respiratory diseases. Pediatric allergic diseases, like eczema, are also sensitive to temperature extremes. During heat waves, the incidences of renal disease, fever and electrolyte imbalance among children increase significantly. Future research is needed to examine the balance between hot- and cold-temperature related mortality and morbidity among children; evaluate the impacts of cold spells on cause-specific mortality in children; identify the most sensitive temperature exposure and health outcomes to quantify the impact of temperature extremes on children; elucidate the possible modifiers of the temperature and children's health relationship; and project children's disease burden under different climate change scenarios. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

Ambient temperature and coronary heart disease mortality in Beijing, China: a time series study

PubMed Central

2012-01-01

Background Many studies have examined the association between ambient temperature and mortality. However, less evidence is available on the temperature effects on coronary heart disease (CHD) mortality, especially in China. In this study, we examined the relationship between ambient temperature and CHD mortality in Beijing, China during 2000 to 2011. In addition, we compared time series and time-stratified case-crossover models for the non-linear effects of temperature. Methods We examined the effects of temperature on CHD mortality using both time series and time-stratified case-crossover models. We also assessed the effects of temperature on CHD mortality by subgroups: gender (female and male) and age (age > =65 and age < 65). We used a distributed lag non-linear model to examine the non-linear effects of temperature on CHD mortality up to 15 lag days. We used Akaike information criterion to assess the model fit for the two designs. Results The time series models had a better model fit than time-stratified case-crossover models. Both designs showed that the relationships between temperature and group-specific CHD mortality were non-linear. Extreme cold and hot temperatures significantly increased the risk of CHD mortality. Hot effects were acute and short-term, while cold effects were delayed by two days and lasted for five days. The old people and women were more sensitive to extreme cold and hot temperatures than young and men. Conclusions This study suggests that time series models performed better than time-stratified case-crossover models according to the model fit, even though they produced similar non-linear effects of temperature on CHD mortality. In addition, our findings indicate that extreme cold and hot temperatures increase the risk of CHD mortality in Beijing, China, particularly for women and old people. PMID:22909034

Brook trout use of thermal refugia and foraging habitat influenced by brown trout

USGS Publications Warehouse

Hitt, Nathaniel P.; Snook, Erin; Massie, Danielle L.

2017-01-01

The distribution of native brook trout (Salvelinus fontinalis) in eastern North America is often limited by temperature and introduced brown trout (Salmo trutta), the relative importance of which is poorly understood but critical for conservation and restoration planning. We evaluated effects of brown trout on brook trout behavior and habitat use in experimental streams across increasing temperatures (14–23 °C) with simulated groundwater upwelling zones providing thermal refugia (6–9 °C below ambient temperatures). Allopatric and sympatric trout populations increased their use of upwelling zones as ambient temperatures increased, demonstrating the importance of groundwater as thermal refugia in warming streams. Allopatric brook trout showed greater movement rates and more even spatial distributions within streams than sympatric brook trout, suggesting interference competition by brown trout for access to forage habitats located outside thermal refugia. Our results indicate that removal of introduced brown trout may facilitate native brook trout expansion and population viability in downstream reaches depending in part on the spatial configuration of groundwater upwelling zones.

Physiological responses to known intake of ergot alkaloids by steers at environmental temperatures within or greater than their thermoneutral zone

NASA Astrophysics Data System (ADS)

Eisemann, Joan; Huntington, Gerald; Williamson, Megan; Hanna, Michelle; Poore, Matthew

2014-11-01

Two studies separated effects of dietary ergot alkaloids from effects of feed intake or ambient temperature on respiration rate (RR), heart rate (HR), surface temperature (ST), rectal temperature (RT), blood pressure (BP), serum hormone, and plasma metabolite concentrations in beef steers. The balanced, single reversal design for each experiment used 8 beef steers fed tall fescue seed (2.5 g/kg body weight, (BW)) with (E+) or without (E-) ergot alkaloids as part of a 60:40 switchgrass hay: supplement diet. Periods were 35 d with 21 d of preliminary phase and 14 d of feeding fescue seed once daily. Measures of dependent variables were collected on d 20, 25, 29 and 35 of each period at 0730 (before feeding), 1230 and 1530. In Expt 1 steers weighed 286 kg, gained 0.61 kg BW/d, E+ supplied 2.72 mg ergot alkaloids including 1.60 mg ergovaline per steer daily, and mean minimum and maximum daily ambient temperatures were 23.6 and 32.3°C. In Expt 2 steers weighed 348 kg, gained 1.03 kg BW/d, E+ supplied 3.06 mg ergot alkaloids including 2.00 mg ergovaline daily, and mean minimum and maximum daily ambient temperatures were 11.9 and 17.4°C. Dry matter intake was not affected by fescue seed treatment (P < 0.20) in either experiment. In both experiments, E+ reduced HR (P < 0.01) and increased insulin (P = 0.07). Systolic BP minus diastolic BP decreased (P< 0.05) for E+ in both experiments, due to increased diastolic BP in Expt 1 (P < 0.03) and decreased systolic BP in Expt 2 (P < 0.07). In Expt 1, above the thermoneutral zone, E+ increased (P< 0.05) RR, RT and left side ST in comparison to E-, but in Expt 2, within the thermoneutral zone, E+ and E- did not differ (P < 0.18). Ergot alkaloids from fescue seed affect the cardiovascular system of steers separately from effects of feed intake or environmental temperature. Ergot alkaloids interact with ambient temperatures above the steers’ thermoneutral zone to exacerbate the symptoms of hyperthermic stress.

Temporal and spatial variation in personal ambient temperatures for outdoor working populations in the southeastern USA

NASA Astrophysics Data System (ADS)

Sugg, Margaret M.; Fuhrmann, Christopher M.; Runkle, Jennifer D.

2018-05-01

Excessive ambient temperature exposure can result in significant morbidity and mortality, especially among vulnerable occupational groups like outdoor workers. Average temperatures in the USA are projected to increase in frequency and intensity, placing future worker populations at greater risk for unhealthy levels of exposure. Unlike previous research focused on aggregate-level temperature exposures from in situ weather station data, this study will measure location-based personal ambient temperatures (PAT) at the individual-level by piloting the use of wearable sensor technology. A total of 66 outdoor workers in three geographically and climatologically diverse regions in the Southeast USA were continuously sampled during the workday for a 1-week period throughout July 11 to August 8 2016. Results indicate significant worker variation in temperature exposure within and between study locations; with PAT characterized by less pronounced variability as workers moved between indoor and outdoor environments. Developed land covers, a factor often associated with higher temperatures, were poorly correlated with PAT. Future analysis should focus on a worker's physiological response to PAT and mapping of spatial patterns of PAT for a larger worker population to produce innovative and targeted heat prevention programs.

The stress corrosion resistance and the cryogenic temperature mechanical properties of annealed Nitronic 60 bar material

NASA Technical Reports Server (NTRS)

Montano, J. W. L.

1977-01-01

Ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion properties of annealed, straightened, and centerless ground Nitronic 60 stainless steel alloy bar material are presented. The mechanical properties of longitudinal specimens were evaluated at test temperatures from ambient to liquid hydrogen. The tensile test data indicated increasing strength with decreasing temperature to -196 C. Below liquid nitrogen temperature the smooth tensile and notched tensile strengths decreased slightly while the elongation and reduction of area decreased drastically. The Charpy V-notched impact energy decreased steadily with decreasing test temperature. Stress corrosion tests were performed on longitudinal tensile specimens and transverse C-ring specimens exposed to: alternate immersion in a 3.5% NaCl bath; humidity cabinet; and a 5% salt spray atmosphere. The longitudinal tensile specimens experienced no corrosive attack. Approximately 3/4 of the transverse C-rings exposed to alternate immersion and to salt spray experienced a pitting attack on the top and bottom ends. Additional stress corrosion tests were performed on transverse tensile specimens. No failures occurred in the 90% stressed specimens exposed for 90 days in the alternate immersion and salt spray environments

Impact of elevated temperatures on specific leaf weight, stomatal density, photosynthesis and chlorophyll fluorescence in soybean.

PubMed

Jumrani, Kanchan; Bhatia, Virender Singh; Pandey, Govind Prakash

2017-03-01

High-temperature stress is a major environmental stress and there are limited studies elucidating its impact on soybean (Glycine max L. Merril.). The objectives of present study were to quantify the effect of high temperature on changes in leaf thickness, number of stomata on adaxial and abaxial leaf surfaces, gas exchange, chlorophyll fluorescence parameters and seed yield in soybean. Twelve soybean genotypes were grown at day/night temperatures of 30/22, 34/24, 38/26 and 42/28 °C with an average temperature of 26, 29, 32 and 35 °C, respectively, under greenhouse conditions. One set was also grown under ambient temperature conditions where crop season average maximum, minimum and mean temperatures were 28.0, 22.4 and 25.2 °C, respectively. Significant negative effect of temperature was observed on specific leaf weight (SLW) and leaf thickness. Rate of photosynthesis, stomatal conductance and water use efficiency declined as the growing temperatures increased; whereas, intercellular CO 2 and transpiration rate were increased. With the increase in temperature chlorophyll fluorescence parameters such as Fv/Fm, qP and PhiPSII declined while there was increase in qN. Number of stomata on both abaxial and adaxial surface of leaf increased significantly with increase in temperatures. The rate of photosynthesis, PhiPSII, qP and SPAD values were positively associated with leaf thickness and SLW. This indicated that reduction in photosynthesis and associated parameters appears to be due to structural changes observed at higher temperatures. The average seed yield was maximum (13.2 g/pl) in plants grown under ambient temperature condition and declined by 8, 14, 51 and 65% as the temperature was increased to 30/22, 34/24, 38/26 and 42/28 °C, respectively.

Temperature characteristics of winter roost-sites for birds and mammals: tree cavities and anthropogenic alternatives

NASA Astrophysics Data System (ADS)

Grüebler, Martin U.; Widmer, Silv; Korner-Nievergelt, Fränzi; Naef-Daenzer, Beat

2014-07-01

The microclimate of potential roost-sites is likely to be a crucial determinant in the optimal roost-site selection of endotherms, in particular during the winter season of temperate zones. Available roost-sites for birds and mammals in European high trunk orchards are mainly tree cavities, wood stacks and artificial nest boxes. However, little is known about the microclimatic patterns inside cavities and thermal advantages of using these winter roost-sites. Here, we simultaneously investigate the thermal patterns of winter roost-sites in relation to winter ambient temperature and their insulation capacity. While tree cavities and wood stacks strongly buffered the daily cycle of temperature changes, nest boxes showed low buffering capacity. The buffering effect of tree cavities was stronger at extreme ambient temperatures compared to temperatures around zero. Heat sources inside roosts amplified Δ T (i.e., the difference between inside and outside temperatures), particularly in the closed roosts of nest boxes and tree cavities, and less in the open wood stacks with stronger circulation of air. Positive Δ T due to the installation of a heat source increased in cold ambient temperatures. These results suggest that orchard habitats in winter show a spatiotemporal mosaic of sites providing different thermal benefits varying over time and in relation to ambient temperatures. At cold temperatures tree cavities provide significantly higher thermal benefits than nest boxes or wood stacks. Thus, in winter ecology of hole-using endotherms, the availability of tree cavities may be an important characteristic of winter habitat quality.

Seasonal acclimatization determined by non-invasive measurements of coat insulation.

PubMed

Langman, Vaughan A; Langman, Sarah L; Ellifrit, Nancy

2015-01-01

Seasonal acclimatization in terrestrial mammals in the Northern Hemisphere involves changes in coat insulation. It is more economical to provide increased insulation than increased heat production for protection against the cold. This study was done to test a technique for the non-invasive measurement of mammal coat insulation and to measure coat insulation over several seasons on captive exotics. The working hypothesis was that species that have no coat or have a coat that does not change seasonally do not acclimatize seasonally. Three surface temperature readings were measured from the torso area. The insulation was calculated using measured metabolic rates and body temperature when possible. The African elephants, giraffe and okapi did not acclimatize with average maximum insulation values of 0.256°Cm(2)  W(-1) . The Amur tigers and mountain goats acclimatized to seasonal ambient conditions by increasing the insulation values of the hair coats in the cold with an average maximum insulation values of 0.811°Cm(2)  W(-1) . The cold adapted species are more than three times more insulated in the cold than the equatorial species. The husbandry implications of exotics that have no ability to acclimatize to Northern Hemisphere seasonal ambient changes are profound. Giraffe, African elephants, and okapi when exposed to cold conditions with ambient air temperatures below 21°C will use body energy reserves to maintain a heat balance and will require housing that provides ambient conditions of 21°C. © 2015 Wiley Periodicals, Inc.

Effect of increased fuel temperature on emissions of oxides of nitrogen from a gas turbine combustor burning natural gas

NASA Technical Reports Server (NTRS)

Marchionna, N. R.

1973-01-01

An annular gas turbine combustor was tested with heated natural gas fuel to determine the effect of increasing fuel temperature on the formation of oxides of nitrogen. Fuel temperatures ranged from ambient to 800 K (980 F). Combustor pressure was 6 atmospheres and the inlet air temperature ranged from 589 to 894 K (600 to 1150 F). The NOx emission index increased with fuel temperature at a rate of 4 to 9 percent per 100 K (180 F), depending on the inlet air temperature. The rate of increase in NOx was lowest at the highest inlet air temperature tested.

Psychophysics of a Nociceptive Test in the Mouse: Ambient Temperature as a Key Factor for Variation

PubMed Central

Pincedé, Ivanne; Pollin, Bernard; Meert, Theo; Plaghki, Léon; Le Bars, Daniel

2012-01-01

Background The mouse is increasingly used in biomedical research, notably in behavioral neurosciences for the development of tests or models of pain. Our goal was to provide the scientific community with an outstanding tool that allows the determination of psychophysical descriptors of a nociceptive reaction, which are inaccessible with conventional methods: namely the true threshold, true latency, conduction velocity of the peripheral fibers that trigger the response and latency of the central decision-making process. Methodology/Principal Findings Basically, the procedures involved heating of the tail with a CO2 laser, recording of tail temperature with an infrared camera and stopping the heating when the animal reacted. The method is based mainly on the measurement of three observable variables, namely the initial temperature, the heating rate and the temperature reached at the actual moment of the reaction following random variations in noxious radiant heat. The initial temperature of the tail, which itself depends on the ambient temperature, very markedly influenced the behavioral threshold, the behavioral latency and the conduction velocity of the peripheral fibers but not the latency of the central decision-making. Conclusions/Significance We have validated a psychophysical approach to nociceptive reactions for the mouse, which has already been described for rats and Humans. It enables the determination of four variables, which contribute to the overall latency of the response. The usefulness of such an approach was demonstrated by providing new fundamental findings regarding the influence of ambient temperature on nociceptive processes. We conclude by challenging the validity of using as “pain index" the reaction time of a behavioral response to an increasing heat stimulus and emphasize the need for a very careful control of the ambient temperature, as a prevailing environmental source of variation, during any behavioral testing of mice. PMID:22629325

Ambient temperature and FIT performance in the Emilia-Romagna colorectal cancer screening programme.

PubMed

De Girolamo, Gianfranco; Goldoni, Carlo A; Corradini, Rossella; Giuliani, Orietta; Falcini, Fabio; Sassoli De'Bianchi, Priscilla; Naldoni, Carlo; Zauli Sajani, Stefano

2016-12-01

To assess the impact of ambient temperature on faecal immunochemical test (FIT) performance in the colorectal cancer screening programme of Emilia-Romagna (Italy). A population-based retrospective cohort study on data from 2005 to 2011. Positive rate, detection rate, and positive predictive value rate for cancers and adenomas, and incidence rate of interval cancers after negative tests were analysed using Poisson regression models. In addition to ambient temperature, gender, age, screening history, and Local Health Unit were also considered. In 1,521,819 tests analysed, the probability of a positive result decreased linearly with increasing temperature. Point estimates and 95% Confidence Intervals were estimated for six temperature classes (<5, 5 |-10, 10 |-15, 15 |-20, 20|-25 and ≥25℃), and referred to the 5|-10℃ class. The positive rate ratio was significantly related to temperature increase: 0.99 (0.97-1.02), 1, 0.98 (0.96-1.00), 0.96 (0.94-0.99), 0.93 (0.91-0.96), 0.92 (0.89-0.95). A linear trend was also evident for advanced adenoma detection rate ratio: 1.00 (0.96-1.04), 1, 0.98 (0.93-1.02), 0.96 (0.92-1.00), 0.92 (0.88-0.96), 0.94 (0.88-1.01). The effect was less linear, but still important, for cancer detection rates: 0.95 (0.85-1.06), 1, 1.00 (0.90-1.10), 0.94 (0.85-1.05), 0.81 (0.72-0.92), 0.93 (0.80-1.09). No association or linear trend was found for positive predictive values or risk of interval cancer, despite an excess of +16% in the highest temperature class for interval cancer. Ambient temperatures can affect screening performance. Continued monitoring is needed to verify the effect of introducing FIT tubes with a new buffer, which should guarantee a higher stability of haemoglobin. © The Author(s) 2016.

Equivalent circuit model of converse magnetoelectric effect for the tri-layer magnetoelectric laminates with thermal and stress loadings

NASA Astrophysics Data System (ADS)

Zhou, Hao-Miao; Li, Meng-Han; Liu, Hui; Cui, Xiao-Le

2015-12-01

For the converse magnetoelectric coupling effect of the piezoelectric/magnetostrictive/piezoelectric tri-layer symmetric magnetoelectric laminates, based on the nonlinear thermo-magneto-mechanical constitutive equations of the giant magnetostrictive materials and the thermo-electro-mechanical constitutive equations of the piezoelectric materials, according to Newton's second law and the magnetic circuit theorem, an equivalent circuit is established. Then an expression of the converse magnetoelectric coefficient describing nonlinear thermo-magneto-electro-mechanical coupling is established. The curve of the nonlinear converse magnetoelectric coefficient versus the bias magnetic field, is predicted effectively by the expression, and the predictions are in good agreement with the experimental result both qualitatively and quantitatively. Furthermore, the model can predict the complex influences of the bias magnetic field, the stress and the ambient temperature on the converse magnetoelectric coefficient. It can be found from these predictions that the converse magnetoelectric coefficient decreases with the increasing temperature and increases with the increasing tensile stress. Under the common effect of the ambient temperature and the stress, it is also found that the converse magnetoelectric coefficient changes sharply with the ambient temperature when the tensile stress is applied on the laminates, but it has a good stability of temperature when a large compressive stress is applied. Therefore, this work contributes to the researches on the giant converse magnetoelectric coefficient and the designs of magnetoelectric devices based on the converse magnetoelectric coupling.

Heat, heat waves, and out-of-hospital cardiac arrest.

PubMed

Kang, Si-Hyuck; Oh, Il-Young; Heo, Jongbae; Lee, Hyewon; Kim, Jungeun; Lim, Woo-Hyun; Cho, Youngjin; Choi, Eue-Keun; Yi, Seung-Muk; Sang, Do Shin; Kim, Ho; Youn, Tae-Jin; Chae, In-Ho; Oh, Seil

2016-10-15

Cardiac arrest is one of the common presentations of cardiovascular disorders and a leading cause of death. There are limited data on the relationship between out-of-hospital cardiac arrest (OHCA) and ambient temperatures, specifically extreme heat. This study investigated how heat and heat waves affect the occurrence of OHCA. Seven major cities in Korea with more than 1 million residents were included in this study. A heat wave was defined as a daily mean temperature above the 98th percentile of the yearly distribution for at least two consecutive days. A total of 50,318 OHCAs of presumed cardiac origin were identified from the nationwide emergency medical service database between 2006 and 2013. Ambient temperature and OHCA had a J-shaped relationship with a trough at 28°C. Heat waves were shown to be associated with a 14-% increase in the risk of OHCA. Adverse effects were apparent from the beginning of each heat wave period and slightly increased during its continuation. Excess OHCA events during heat waves occurred between 3PM and 5PM. Subgroup analysis showed that those 65years or older were significantly more susceptible to heat waves. Ambient temperature and OHCA had a J-shaped relationship. The risk of OHCA was significantly increased with heat waves. Excess OHCA events primarily occurred during the afternoon when the temperature was high. We found that the elderly were more susceptible to the deleterious effects of heat waves. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effect of transportation during periods of high ambient temperature on physiologic and behavioral indices of beef heifers.

PubMed

Theurer, Miles E; White, Brad J; Anderson, David E; Miesner, Matt D; Mosier, Derek A; Coetzee, Johann F; Amrine, David E

2013-03-01

To determine the effect of transportation during periods of high ambient temperature on physiologic and behavioral indices of beef heifers. 20 heifers (mean body weight, 217.8 kg). Ten heifers were transported 518 km when the maximum ambient temperature was ≥ 32.2°C while the other 10 heifers served as untransported controls. Blood samples were collected from transported heifers at predetermined intervals during the transportation period. For all heifers, body weights, nasal and rectal temperatures, and behavioral indices were measured at predetermined intervals for 3 days after transportation. A week later, the entire process was repeated such that each group was transported twice and served as the control twice. Transported heifers spent more time near the hay feeder on the day of transportation, had lower nasal and rectal temperatures for 24 hours after transportation, and spent more time lying down for 2 days after transportation, compared with those indices for control heifers. Eight hours after transportation, the weight of transported heifers decreased 6%, whereas that of control heifers increased 0.6%. At 48 hours after initiation of transportation, weight, rectal temperature, and time spent at various pen locations did not differ between transported and control heifers. Cortisol concentrations were higher 4 hours after initiation of transportation, compared with those determined just prior to transportation. Results indicated transportation during periods of high ambient temperatures caused transient changes in physiologic and behavioral indices of beef heifers.

[Heat exchange of the rat in thermoneutral zone temperature and comparison with heat exchange in ambient temperature over and under it].

PubMed

Rumiantsev, G V

2011-08-01

With the help of thermonetry and general calorimetry body temperature and heat production in ambient temperatures 20 degrees C, 28 degrees C, 33 degrees C were recorded. The experiments showed, that at the temperature 20 degrees C the rectal temperature was changing very little. But in ambient temperature 33 degrees C the rectal temperature was 40.5 +/- 0.1 degrees C.

Ambient-temperature diffusion and gettering of Pt atoms in GaN with surface defect region under 60Co gamma or MeV electron irradiation

NASA Astrophysics Data System (ADS)

Hou, Ruixiang; Li, Lei; Fang, Xin; Xie, Ziang; Li, Shuti; Song, Weidong; Huang, Rong; Zhang, Jicai; Huang, Zengli; Li, Qiangjie; Xu, Wanjing; Fu, Engang; Qin, G. G.

2018-01-01

Generally, the diffusion and gettering of impurities in GaN needs high temperature. Calculated with the ambient-temperature extrapolation value of the high temperature diffusivity of Pt atoms in GaN reported in literature, the time required for Pt atoms diffusing 1 nm in GaN at ambient temperature is about 19 years. Therefore, the ambient-temperature diffusion and gettering of Pt atoms in GaN can hardly be observed. In this work, the ambient-temperature diffusion and gettering of Pt atoms in GaN is reported for the first time. It is demonstrated by use of secondary ion mass spectroscopy that in the condition of introducing a defect region on the GaN film surface by plasma, and subsequently, irradiated by 60Co gamma-ray or 3 MeV electrons, the ambient-temperature diffusion and gettering of Pt atoms in GaN can be detected. It is more obvious with larger irradiation dose and higher plasma power. With a similar surface defect region, the ambient-temperature diffusion and gettering of Pt atoms in GaN stimulated by 3 MeV electron irradiation is more marked than that stimulated by gamma irradiation. The physical mechanism of ambient-temperature diffusion and gettering of Pt atoms in a GaN film with a surface defect region stimulated by gamma or MeV electron irradiation is discussed.

Effect of ambient temperature on nutrient digestibility and nitrogen balance in sheep fed brown-midrib maize silage.

PubMed

Gorniak, Tobias; Meyer, Ulrich; Südekum, Karl-Heinz; Dänicke, Sven

2014-01-01

The aim of the experiment was to determine the impact of heat stress on nutrient digestibility and nitrogen balance in sheep fed silages differing in fibre quality. The digestibility trial was conducted at three different ambient temperatures (15°C, 25°C and 35°C for 24 h/d). The tested brown-midrib maize (Bm) silage had a higher nutrient digestibility, except for ether extract (EE) and a higher metabolisable energy (ME) content than the control maize (Con) silage. Nitrogen (N) excretion with faeces was higher but N excretion with urine was lower for sheep fed Bm silage, subsequently N balance did not differ between the two silages. Temperature had no effect on nutrient digestibility, except for crude protein (CP), but N excretion with urine was lower at elevated temperatures. A diet by temperature interaction was found for dry matter (DM) and organic matter (OM) digestibility. When the ambient temperature increased from 15°C to 25°C, the DM and OM digestibility increased in animals fed Con silage, but decreased in animals fed Bm silage. Concomitantly, ME estimated from digestible nutrients was higher for Bm than for Con at 15°C, but no differences were found at 25°C and 35°C. Effects of diet by temperature interaction, furthermore, were observed for EE and CP digestibility. Therefore, forage quality has to be considered when feeding heat-stressed animals.

Threshold Evaluation of Emergency Risk Communication for Health Risks Related to Hazardous Ambient Temperature.

PubMed

Liu, Yang; Hoppe, Brenda O; Convertino, Matteo

2018-04-10

Emergency risk communication (ERC) programs that activate when the ambient temperature is expected to cross certain extreme thresholds are widely used to manage relevant public health risks. In practice, however, the effectiveness of these thresholds has rarely been examined. The goal of this study is to test if the activation criteria based on extreme temperature thresholds, both cold and heat, capture elevated health risks for all-cause and cause-specific mortality and morbidity in the Minneapolis-St. Paul Metropolitan Area. A distributed lag nonlinear model (DLNM) combined with a quasi-Poisson generalized linear model is used to derive the exposure-response functions between daily maximum heat index and mortality (1998-2014) and morbidity (emergency department visits; 2007-2014). Specific causes considered include cardiovascular, respiratory, renal diseases, and diabetes. Six extreme temperature thresholds, corresponding to 1st-3rd and 97th-99th percentiles of local exposure history, are examined. All six extreme temperature thresholds capture significantly increased relative risks for all-cause mortality and morbidity. However, the cause-specific analyses reveal heterogeneity. Extreme cold thresholds capture increased mortality and morbidity risks for cardiovascular and respiratory diseases and extreme heat thresholds for renal disease. Percentile-based extreme temperature thresholds are appropriate for initiating ERC targeting the general population. Tailoring ERC by specific causes may protect some but not all individuals with health conditions exacerbated by hazardous ambient temperature exposure. © 2018 Society for Risk Analysis.

Direct benefits and indirect costs of warm temperatures for high-elevation populations of a solitary bee.

PubMed

Forrest, Jessica R K; Chisholm, Sarah P M

2017-02-01

Warm temperatures are required for insect flight. Consequently, warming could benefit many high-latitude and high-altitude insects by increasing opportunities for foraging or oviposition. However, warming can also alter species interactions, including interactions with natural enemies, making the net effect of rising temperatures on population growth rate difficult to predict. We investigated the temperature-dependence of nesting activity and lifetime reproductive output over 3 yr in subalpine populations of a pollen-specialist bee, Osmia iridis. Rates of nest provisioning increased with ambient temperatures and with availability of floral resources, as expected. However, warmer conditions did not increase lifetime reproductive output. Lifetime offspring production was best explained by rates of brood parasitism (by the wasp Sapyga), which increased with temperature. Direct observations of bee and parasite activity suggest that although activity of both species is favored by warmer temperatures, bees can be active at lower ambient temperatures, while wasps are active only at higher temperatures. Thus, direct benefits to the bees of warmer temperatures were nullified by indirect costs associated with increased parasite activity. To date, most studies of climate-change effects on pollinators have focused on changing interactions between pollinators and their floral host-plants (i.e., bottom-up processes). Our results suggest that natural enemies (i.e., top-down forces) can play a key role in pollinator population regulation and should not be overlooked in forecasts of pollinator responses to climate change. © 2016 by the Ecological Society of America.

Physical exercise-induced changes in the core body temperature of mice depend more on ambient temperature than on exercise protocol or intensity

NASA Astrophysics Data System (ADS)

Wanner, Samuel Penna; Costa, Kátia Anunciação; Soares, Anne Danieli Nascimento; Cardoso, Valbert Nascimento; Coimbra, Cândido Celso

2014-08-01

The mechanisms underlying physical exercise-induced hyperthermia may be species specific. Therefore, the present study aimed to investigate the effects of exercise intensity and ambient temperature on the core body temperature ( T core) of running mice, which provide an important experimental model for advancing the understanding of thermal physiology. We evaluated the influence of different protocols (constant- or incremental-speed exercises), treadmill speeds and ambient temperatures ( T a) on the magnitude of exercise-induced hyperthermia. To measure T core, a telemetric sensor was implanted in the abdominal cavity of male adult Swiss mice under anesthesia. After recovering from the surgery, the animals were familiarized to running on a treadmill and then subjected to the different running protocols and speeds at two T a: 24 °C or 34 °C. All of the experimental trials resulted in marked increases in T core. As expected, the higher-temperature environment increased the magnitude of running-induced hyperthermia. For example, during incremental exercise at 34 °C, the maximal T core achieved was increased by 1.2 °C relative to the value reached at 24 °C. However, at the same T a, neither treadmill speed nor exercise protocol altered the magnitude of exercise-induced hyperthermia. We conclude that T core of running mice is influenced greatly by T a, but not by the exercise protocols or intensities examined in the present report. These findings suggest that the magnitude of hyperthermia in running mice may be regulated centrally, independently of exercise intensity.

Physical exercise-induced changes in the core body temperature of mice depend more on ambient temperature than on exercise protocol or intensity.

PubMed

Wanner, Samuel Penna; Costa, Kátia Anunciação; Soares, Anne Danieli Nascimento; Cardoso, Valbert Nascimento; Coimbra, Cândido Celso

2014-08-01

The mechanisms underlying physical exercise-induced hyperthermia may be species specific. Therefore, the present study aimed to investigate the effects of exercise intensity and ambient temperature on the core body temperature (T core) of running mice, which provide an important experimental model for advancing the understanding of thermal physiology. We evaluated the influence of different protocols (constant- or incremental-speed exercises), treadmill speeds and ambient temperatures (T a) on the magnitude of exercise-induced hyperthermia. To measure T core, a telemetric sensor was implanted in the abdominal cavity of male adult Swiss mice under anesthesia. After recovering from the surgery, the animals were familiarized to running on a treadmill and then subjected to the different running protocols and speeds at two T a: 24 °C or 34 °C. All of the experimental trials resulted in marked increases in T core. As expected, the higher-temperature environment increased the magnitude of running-induced hyperthermia. For example, during incremental exercise at 34 °C, the maximal T core achieved was increased by 1.2 °C relative to the value reached at 24 °C. However, at the same T a, neither treadmill speed nor exercise protocol altered the magnitude of exercise-induced hyperthermia. We conclude that T core of running mice is influenced greatly by T a, but not by the exercise protocols or intensities examined in the present report. These findings suggest that the magnitude of hyperthermia in running mice may be regulated centrally, independently of exercise intensity.

Time series analysis of the association between ambient temperature and cerebrovascular morbidity in the elderly in Shanghai, China

NASA Astrophysics Data System (ADS)

Zhang, Xian-Jing; Ma, Wei-Ping; Zhao, Nai-Qing; Wang, Xi-Ling

2016-01-01

Research on the association between ambient temperature and cerebrovascular morbidity is scarce in China. In this study, we applied mixed generalized additive model (MGAM) to daily counts of cerebrovascular disease of Shanghai residents aged 65 years or older from 2007-2011, stratified by gender. Weighted daily mean temperature up to lags of one week was smoothed by natural cubic spline, and was added into the model to assess both linear and nonlinear effects of temperature. We found that when the mean temperature increased by 1 °C, the male cases of cerebrovascular disease reduced by 0.95% (95% Confidence Interval (CI): 0.80%, 1.10%) or reduced by 0.34% (95% CI: -0.68, 1.36%) in conditions of temperature was below or above 27 °C. However, for every 1 °C increase in temperature, the female cases of cerebrovascular disease increased by 0.34% (95% CI: -0.26%, 0.94%) or decreased by 0.92% (95% CI: 0.72, 1.11%) in conditions of temperature was below or above 8 °C, respectively. Temperature and cerebrovascular morbidity is negatively associated in Shanghai. MGAM is recommended in assessing the association between environmental hazards and health outcomes in time series studies.

Chemistry and long-term decomposition of roots of Douglas-fir grown under elevated atmospheric carbon dioxide and warming conditions.

PubMed

Chen, H; Rygiewicz, P T; Johnson, M G; Harmon, M E; Tian, H; Tang, J W

2008-01-01

Elevated atmospheric CO(2) concentrations and warming may affect the quality of litters of forest plants and their subsequent decomposition in ecosystems, thereby potentially affecting the global carbon cycle. However, few data on root tissues are available to test this feedback to the atmosphere. In this study, we used fine (diameter < or = 2 mm) and small (2-10 mm) roots of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings that were grown for 4 yr in a 2 x 2 factorial experiment: ambient or elevated (+ 180 ppm) atmospheric CO(2) concentrations, and ambient or elevated (+3.8 degrees C) atmospheric temperature. Exposure to elevated CO(2) significantly increased water-soluble extractives concentration (%WSE), but had little effect on the concentration of N, cellulose, and lignin of roots. Elevated temperature had no effect on substrate quality except for increasing %WSE and decreasing the %lignin content of fine roots. No significant interaction was found between CO(2) and temperature treatments on substrate quality, except for %WSE of the fine roots. Short-term (< or = 9 mo) root decomposition in the field indicated that the roots from the ambient CO(2) and ambient temperature treatment had the slowest rate. However, over a longer period of incubation (9-36 mo) the influence of initial substrate quality on root decomposition diminished. Instead, the location of the field incubation sites exhibited significant control on decomposition. Roots at the warmer, low elevation site decomposed significantly faster than the ones at the cooler, high elevation site. This study indicates that short-term decomposition and long-term responses are not similar. It also suggests that increasing atmospheric CO(2) had little effect on the carbon storage of Douglas-fir old-growth forests of the Pacific Northwest.

Humidity Effects on Fragmentation in Plasma-Based Ambient Ionization Sources

NASA Astrophysics Data System (ADS)

Newsome, G. Asher; Ackerman, Luke K.; Johnson, Kevin J.

2016-01-01

Post-plasma ambient desorption/ionization (ADI) sources are fundamentally dependent on surrounding water vapor to produce protonated analyte ions. There are two reports of humidity effects on ADI spectra. However, it is unclear whether humidity will affect all ADI sources and analytes, and by what mechanism humidity affects spectra. Flowing atmospheric pressure afterglow (FAPA) ionization and direct analysis in real time (DART) mass spectra of various surface-deposited and gas-phase analytes were acquired at ambient temperature and pressure across a range of observed humidity values. A controlled humidity enclosure around the ion source and mass spectrometer inlet was used to create programmed humidity and temperatures. The relative abundance and fragmentation of molecular adduct ions for several compounds consistently varied with changing ambient humidity and also were controlled with the humidity enclosure. For several compounds, increasing humidity decreased protonated molecule and other molecular adduct ion fragmentation in both FAPA and DART spectra. For others, humidity increased fragment ion ratios. The effects of humidity on molecular adduct ion fragmentation were caused by changes in the relative abundances of different reagent protonated water clusters and, thus, a change in the average difference in proton affinity between an analyte and the population of water clusters. Control of humidity in ambient post-plasma ion sources is needed to create spectral stability and reproducibility.

Humidity Effects on Fragmentation in Plasma-Based Ambient Ionization Sources.

PubMed

Newsome, G Asher; Ackerman, Luke K; Johnson, Kevin J

2016-01-01

Post-plasma ambient desorption/ionization (ADI) sources are fundamentally dependent on surrounding water vapor to produce protonated analyte ions. There are two reports of humidity effects on ADI spectra. However, it is unclear whether humidity will affect all ADI sources and analytes, and by what mechanism humidity affects spectra. Flowing atmospheric pressure afterglow (FAPA) ionization and direct analysis in real time (DART) mass spectra of various surface-deposited and gas-phase analytes were acquired at ambient temperature and pressure across a range of observed humidity values. A controlled humidity enclosure around the ion source and mass spectrometer inlet was used to create programmed humidity and temperatures. The relative abundance and fragmentation of molecular adduct ions for several compounds consistently varied with changing ambient humidity and also were controlled with the humidity enclosure. For several compounds, increasing humidity decreased protonated molecule and other molecular adduct ion fragmentation in both FAPA and DART spectra. For others, humidity increased fragment ion ratios. The effects of humidity on molecular adduct ion fragmentation were caused by changes in the relative abundances of different reagent protonated water clusters and, thus, a change in the average difference in proton affinity between an analyte and the population of water clusters. Control of humidity in ambient post-plasma ion sources is needed to create spectral stability and reproducibility.

Trailer microclimate and calf welfare during fall-run transportation of beef calves in Alberta.

PubMed

Goldhawk, C; Janzen, E; González, L A; Crowe, T; Kastelic, J; Pajor, E; Schwartzkopf-Genswein, K S

2014-11-01

Twenty-four commercial loads of beef calves (BW 300 ± 52 kg, mean ± SD) were evaluated for associations among transportation factors, in-transit microclimate, and calf welfare. Transport factors evaluated included vehicle speed, space allowance, compartment within trailer, and transit duration. Calves were transported for 7 h 44 min ± 4 h 15 min, with space allowances ranging from 0.56 to 1.17 m(2)/animal. Compartment within trailer, space allowance, and vehicle speed did not affect the difference between compartment ceiling-level and ambient temperatures during a 30-min period of steady-state microclimate. During the steady-state period, a 1°C increase in ambient temperature above the mean of 5.6°C was associated with a 0.62°C decrease in the difference between ceiling-level and ambient temperature (P < 0.01). Ceiling-level temperature and humidity during the first 400 min of transport could be predicted by ambient conditions and vehicle speed (pseudo-r(2) of 0.91 and 0.82 for temperature and humidity ratio; P < 0.01). Events when animal-level temperature-humidity index (THI) was classified as above the "danger" level lasted for 10.2 ± 4.1 consecutive minutes. Ambient and ceiling-level THI values were not classified as above "danger" for 90.0 and 84.9% of animal-level events. Ambient and ceiling-level THI were 5.0 ± 2.1 and 4.7 ± 2.0° Flower than animal-level THI during periods of disagreement, respectively. The majority of calves arrived in good condition and biochemical indicators of calf welfare were within reference ranges for healthy cattle. Within the study population, high pre-transport cortisol and hematocrit were associated with elevated post-transport values (P < 0.01). A 1% increase in shrink during the weaning to loading interval (24 or 48 h) decreased transportation shrink by 0.26 ± 0.04% when average animal-level temperature was greater than 5°C and decreased transportation shrink by 0.11 ± 0.04% when average animal-level temperature was less than 5°C (P < 0.01). We inferred that the study results support future investigation of the extension of in-transit microclimate as a risk factor for post-transport treatment for disease. The study also provided correction factors for estimating in-transit microclimate that could assist in evaluation of transportation management and decisions affecting profitability and calf welfare.

Electrical connection structure for a superconductor element

DOEpatents

Lallouet, Nicolas; Maguire, James

2010-05-04

The invention relates to an electrical connection structure for a superconductor element cooled by a cryogenic fluid and connected to an electrical bushing, which bushing passes successively through an enclosure at an intermediate temperature between ambient temperature and the temperature of the cryogenic fluid, and an enclosure at ambient temperature, said bushing projecting outside the ambient temperature enclosure. According to the invention, said intermediate enclosure is filled at least in part with a solid material of low thermal conductivity, such as a polyurethane foam or a cellular glass foam. The invention is applicable to connecting a superconductor cable at cryogenic temperature to a device for equipment at ambient temperature.

Contribution of honeybee drones of different age to colonial thermoregulation*

PubMed Central

Kovac, Helmut; Stabentheiner, Anton; Brodschneider, Robert

2011-01-01

In addition to honeybee workers, drones also contribute to colonial thermoregulation. We show the drones’ contribution to thermoregulation at 5 different experimental temperatures ranging from 15–34 °C. The frequency and the degree of endothermy depended on the drones’ local ambient temperature and age. Location on brood or non-brood areas had no influence. The frequency of endothermic drones and the intensity of endothermy increased with decreasing temperature. 30% of drones of 8 days and older heated their thorax by more than 1 °C above the abdomen. The youngest drones (0–2 days) did not exceed this level of endothermy. Though young drones were less often engaged in active heat production, their contribution to brood warming was not insignificant because their abundance on the brood nest was 3.5 times higher than that of the oldest drones (≥13 days). Results suggest that the stimulus for the drones’ increased frequency of heating at low experimental temperatures was their low local ambient air and/or comb temperature. PMID:22140282

Contribution of honeybee drones of different age to colonial thermoregulation.

PubMed

Kovac, Helmut; Stabentheiner, Anton; Brodschneider, Robert

2009-01-01

In addition to honeybee workers, drones also contribute to colonial thermoregulation. We show the drones' contribution to thermoregulation at 5 different experimental temperatures ranging from 15-34 °C. The frequency and the degree of endothermy depended on the drones' local ambient temperature and age. Location on brood or non-brood areas had no influence. The frequency of endothermic drones and the intensity of endothermy increased with decreasing temperature. 30% of drones of 8 days and older heated their thorax by more than 1 °C above the abdomen. The youngest drones (0-2 days) did not exceed this level of endothermy. Though young drones were less often engaged in active heat production, their contribution to brood warming was not insignificant because their abundance on the brood nest was 3.5 times higher than that of the oldest drones (≥13 days). Results suggest that the stimulus for the drones' increased frequency of heating at low experimental temperatures was their low local ambient air and/or comb temperature.

The cold effect of ambient temperature on ischemic and hemorrhagic stroke hospital admissions: A large database study in Beijing, China between years 2013 and 2014-Utilizing a distributed lag non-linear analysis.

PubMed

Luo, Yanxia; Li, Haibin; Huang, Fangfang; Van Halm-Lutterodt, Nicholas; Qin Xu; Wang, Anxin; Guo, Jin; Tao, Lixin; Li, Xia; Liu, Mengyang; Zheng, Deqiang; Chen, Sipeng; Zhang, Feng; Yang, Xinghua; Tan, Peng; Wang, Wei; Xie, Xueqin; Guo, Xiuhua

2018-01-01

The effects of ambient temperature on stroke death in China have been well addressed. However, few studies are focused on the attributable burden for the incident of different types of stroke due to ambient temperature, especially in Beijing, China. We purpose to assess the influence of ambient temperature on hospital stroke admissions in Beijing, China. Data on daily temperature, air pollution, and relative humidity measurements and stroke admissions in Beijing were obtained between 2013 and 2014. Distributed lag non-linear model was employed to determine the association between daily ambient temperature and stroke admissions. Relative risk (RR) with 95% confidence interval (CI) and Attribution fraction (AF) with 95% CI were calculated based on stroke subtype, gender and age group. A total number of 147, 624 stroke admitted cases (including hemorrhagic and ischemic types of stroke) were documented. A non-linear acute effect of cold temperature on ischemic and hemorrhagic stroke hospital admissions was evaluated. Compared with the 25th percentile of temperature (1.2 °C), the cumulative RR of extreme cold temperature (first percentile of temperature, -9.6 °C) was 1.51 (95% CI: 1.08-2.10) over lag 0-14 days for ischemic type and 1.28 (95% CI: 1.03-1.59) for hemorrhagic stroke over lag 0-3 days. Overall, 1.57% (95% CI: 0.06%-2.88%) of ischemic stroke and 1.90% (95% CI: 0.40%-3.41%) of hemorrhagic stroke was attributed to the extreme cold temperature over lag 0-7 days and lag 0-3 days, respectively. The cold temperature's impact on stroke admissions was found to be more obvious in male gender and the youth compared to female gender and the elderly. Exposure to extreme cold temperature is associated with increasing both ischemic and hemorrhagic stroke admissions in Beijing, China. Copyright © 2017 Elsevier Ltd. All rights reserved.

Environment-, drug- and stress-induced alterations in body temperature affect the neurotoxicity of substituted amphetamines in the C57BL/6J mouse.

PubMed

Miller, D B; O'Callaghan, J P

1994-08-01

In the companion paper we demonstrated that d-methamphetamine (d-METH), d-methylenedioxyamphetamine (d-MDA) and d-methylenedioxymethamephetamine (d-MDMA), but not d-fenfluramine (d-FEN), appear to damage dopaminergic projections to the striatum of the mouse. An elevation in core temperature also was associated with exposure to d-METH, d-MDA and d-MDMA, whereas exposure to d-FEN lowered core temperature. Given these findings, we examined the effects of temperature on substituted amphetamine (AMP)-induced neurotoxicity in the C57BL/6J mouse. Levels of striatal dopamine (DA) and glial fibrillary acidic protein (GFAP) were taken as indicators of neurotoxicity. Alterations in ambient temperature, pretreatment with drugs reported to cause hypothermia in the mouse and hypothermia induced by restraint stress were used to affect AMP-induced neurotoxicity. Mice received d-METH (10 mg/kg), d-MDA (20 mg/kg) or d-MDMA (20 mg/kg) every 2 hr for a total of four s.c. injections. All three AMPs increased core temperature and caused large (> 75%) decreases in striatal dopamine and large (> 300%) increases in striatal glial fibrillary acidic protein 72 hr after the last injection. Lowering ambient temperature from 22 degrees C to 15 degrees C blocked (d-MDA and d-MDMA) or severely attenuated (d-METH) these effects. Pretreatment with MK-801 lowered core temperature and blocked AMP-induced neurotoxicity; elevation of ambient temperature during this regimen elevated core temperature and markedly attenuated the neuroprotective effects of MK-801. Pretreatment with MK-801 also lowered core temperature in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice but did not block 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Sub-to super-ambient temperature programmable microfabricated gas chromatography column

DOEpatents

Robinson, Alex L.; Anderson, Lawrence F.

2004-03-16

A sub- to super-ambient temperature programmable microfabricated gas chromatography column enables more efficient chemical separation of chemical analytes in a gas mixture by combining a thermoelectric cooler and temperature sensing on the microfabricated column. Sub-ambient temperature programming enables the efficient separation of volatile organic compounds and super-ambient temperature programming enables the elution of less volatile analytes within a reasonable time. The small heat capacity and thermal isolation of the microfabricated column improves the thermal time response and power consumption, both important factors for portable microanalytical systems.

The impact of ambient fine particles on influenza transmission and the modification effects of temperature in China: A multi-city study.

PubMed

Chen, Gongbo; Zhang, Wenyi; Li, Shanshan; Zhang, Yongming; Williams, Gail; Huxley, Rachel; Ren, Hongyan; Cao, Wei; Guo, Yuming

2017-01-01

There is good evidence that air pollution is a risk factor for adverse respiratory and vascular health outcomes. However, data are limited as to whether ambient fine particles contribute to the transmission of influenza and if so, how the association is modified by weather conditions. We examined the relationship between ambient PM 2.5 and influenza incidence at the national level in China and explored the associations at different temperatures. Daily data on concentrations of particulate matter with aerodynamic diameter<2.5μm (PM 2.5 ) and influenza incidence counts were collected in 47 Chinese cities. A Poisson regression model was used to estimate the city-specific PM 2.5 -influenza association, after controlling for potential confounders. Then, a random-effect meta-analysis was used to pool the effects at national level. In addition, stratified analyses were performed to examine modification effects of ambient temperature. For single lag models, the highest effect of ambient PM 2.5 on influenza incidence appeared at lag day 2, with relative risk (RR) of 1.015 (95% confidence interval (CI): 1.004, 1.025) associated with a 10μg/m 3 increase in PM 2.5 . For moving average lag models, the significant association was found at lag 2-3days, with RR of 1.020 (95% CI: 1.006, 1.034). The RR of influenza transmission associated with PM 2.5 was higher for cold compared with hot days. Overall, 10.7% of incident influenza cases may result from exposure to ambient PM 2.5 . Ambient PM 2.5 may increase the risk of exposure to influenza in China especially on cooler days. Control measures to reduce PM 2.5 concentrations could potentially also be of benefit in lowering the risk of exposure and subsequent transmission of influenza in China. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of zinc sulfate pretreatment on heat tolerance of Bama miniature pig under high ambient temperature.

PubMed

Li, Y; Cao, Y; Zhou, X; Wang, F; Shan, T; Li, Z; Xu, W; Li, C

2015-07-01

The aim of this study was to evaluate the heat tolerance of Bama miniature pigs under high ambient temperature (40°C) and Zn interactive functions during heat treatment (HT). Bama miniature pigs (male; n = 24; 6-mo old; BW = 10.79 ± 0.06 kg) were randomly allotted to 4 groups and were fed a basal diet or the basal diet supplemented with 1,500 mg of Zn (ZnSO4·H2O)/kg diet for 38 d. At 7 mo of age (d 30), the thermal neutral (TN) groups remained at 25°C, whereas the HT groups were exposed to ambient temperature at 40°C for 5 h daily for 8 consecutive days. Pigs in 4 groups were sacrificed on d 38. Individual rectal temperatures, skin temperatures, and breathing rates were recorded at 3 h after the onset of HT and the blood samples were collected immediately after HT on d 30, 34, and 38. Pigs fed diets with or without Zn doubled their breathing rates (P < 0.05) and increased body surface, scrotal, and rectal temperatures during HT on d 30, 34, and 38, respectively. Zinc supplementation increased BW gain (BWG; P < 0.05) during 38-d experiment period, and HT decreased BWG only from d 30 to 34 (P < 0.05). Heat treatment increased serum testosterone on d 30 (P < 0.05). Zinc supplementation decreased the heat-induced increase of testosterone in HT on d 30 and 34 (P < 0.05). The relative weight of liver increased in HT groups (P < 0.05). Zinc supplementation decreased the relative weights of spleen (P < 0.05) and testis (P < 0.01). The values of abnormal lymphocyte count and large unstained cell count declined approximately 5 times in groups of Zn supplementation, whereas Zn supplementation increased the values of red blood cell count, hemoglobin, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin. Zinc concentrations increased in serum, liver, kidney, epididymis, longissimus, hair, and feces in groups fed with Zn (P < 0.01). However, additional Zn decreased Zn concentrations in lung, spleen, and testis (P < 0.01). Moreover, HT decreased serum Zn concentrations (P < 0.01). In conclusion, Zn supplementation could be used to alleviate the decline of serum Zn during periods of high ambient temperatures. However, pretreated supplementation with pharmacological Zn did not promote heat tolerance but impacted the erythropoiesis, immunity, and reproductive organ development in Bama miniature pigs.

Temperature effects on particulate emissions from DPF-equipped diesel trucks operating on conventional and biodiesel fuels.

PubMed

Book, Emily K; Snow, Richard; Long, Thomas; Fang, Tiegang; Baldauf, Richard

2015-06-01

Emissions tests were conducted on two medium heavy-duty diesel trucks equipped with a particulate filter (DPF), with one vehicle using a NOx absorber and the other a selective catalytic reduction (SCR) system for control of nitrogen oxides (NOx). Both vehicles were tested with two different fuels (ultra-low-sulfur diesel [ULSD] and biodiesel [B20]) and ambient temperatures (70ºF and 20ºF), while the truck with the NOx absorber was also operated at two loads (a heavy weight and a light weight). The test procedure included three driving cycles, a cold start with low transients (CSLT), the federal heavy-duty urban dynamometer driving schedule (UDDS), and a warm start with low transients (WSLT). Particulate matter (PM) emissions were measured second-by-second using an Aethalometer for black carbon (BC) concentrations and an engine exhaust particle sizer (EEPS) for particle count measurements between 5.6 and 560 nm. The DPF/NOx absorber vehicle experienced increased BC and particle number concentrations during cold starts under cold ambient conditions, with concentrations two to three times higher than under warm starts at higher ambient temperatures. The average particle count for the UDDS showed an opposite trend, with an approximately 27% decrease when ambient temperatures decreased from 70ºF to 20ºF. This vehicle experienced decreased emissions when going from ULSD to B20. The DPF/SCR vehicle tested had much lower emissions, with many of the BC and particle number measurements below detectable limits. However, both vehicles did experience elevated emissions caused by DPF regeneration. All regeneration events occurred during the UDDS cycle. Slight increases in emissions were measured during the WSLT cycles after the regeneration. However, the day after a regeneration occurred, both vehicles showed significant increases in particle number and BC for the CSLT drive cycle, with increases from 93 to 1380% for PM number emissions compared with tests following a day with no regeneration. The use of diesel particulate filters (DPFs) on trucks is becoming more common throughout the world. Understanding how DPFs affect air pollution emissions under varying operating conditions will be critical in implementing effective air quality standards. This study evaluated particulate matter (PM) and black carbon (BC) emissions with two DPF-equipped heavy-duty diesel trucks operating on conventional fuel and a biodiesel fuel blend at varying ambient temperatures, loads, and drive cycles.

Mutation design of a thermophilic Rubisco based on three-dimensional structure enhances its activity at ambient temperature.

PubMed

Fujihashi, Masahiro; Nishitani, Yuichi; Kiriyama, Tomohiro; Aono, Riku; Sato, Takaaki; Takai, Tomoyuki; Tagashira, Kenta; Fukuda, Wakao; Atomi, Haruyuki; Imanaka, Tadayuki; Miki, Kunio

2016-10-01

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) plays a central role in carbon dioxide fixation on our planet. Rubisco from a hyperthermophilic archaeon Thermococcus kodakarensis (Tk-Rubisco) shows approximately twenty times the activity of spinach Rubisco at high temperature, but only one-eighth the activity at ambient temperature. We have tried to improve the activity of Tk-Rubisco at ambient temperature, and have successfully constructed several mutants which showed higher activities than the wild-type enzyme both in vitro and in vivo. Here, we designed new Tk-Rubisco mutants based on its three-dimensional structure and a sequence comparison of thermophilic and mesophilic plant Rubiscos. Four mutations were introduced to generate new mutants based on this strategy, and one of the four mutants, T289D, showed significantly improved activity compared to that of the wild-type enzyme. The crystal structure of the Tk-Rubisco T289D mutant suggested that the increase in activity was due to mechanisms distinct from those involved in the improvement in activity of Tk-Rubisco SP8, a mutant protein previously reported to show the highest activity at ambient temperature. Combining the mutations of T289D and SP8 successfully generated a mutant protein (SP8-T289D) with the highest activity to date both in vitro and in vivo. The improvement was particularly pronounced for the in vivo activity of SP8-T289D when introduced into the mesophilic, photosynthetic bacterium Rhodopseudomonas palustris, which resulted in a strain with nearly two-fold higher specific growth rates compared to that of a strain harboring the wild-type enzyme at ambient temperature. Proteins 2016; 84:1339-1346. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

The thermal regime around buried submarine high-voltage cables

NASA Astrophysics Data System (ADS)

Emeana, C. J.; Hughes, T. J.; Dix, J. K.; Gernon, T. M.; Henstock, T. J.; Thompson, C. E. L.; Pilgrim, J. A.

2016-08-01

The expansion of offshore renewable energy infrastructure and the need for trans-continental shelf power transmission require the use of submarine high-voltage (HV) cables. These cables have maximum operating surface temperatures of up to 70 °C and are typically buried 1-2 m beneath the seabed, within the wide range of substrates found on the continental shelf. However, the heat flow pattern and potential effects on the sedimentary environments around such anomalously high heat sources in the near-surface sediments are poorly understood. We present temperature measurements from a 2-D laboratory experiment representing a buried submarine HV cable, and identify the thermal regimes generated within typical unconsolidated shelf sediments—coarse silt, fine sand and very coarse sand. We used a large (2 × 2.5 m2) tank filled with water-saturated spherical glass beads (ballotini) and instrumented with a buried heat source and 120 thermocouples to measure the time-dependent 2-D temperature distributions. The observed and corresponding Finite Element Method simulations of the steady state heat flow regimes and normalized radial temperature distributions were assessed. Our results show that the heat transfer and thus temperature fields generated from submarine HV cables buried within a range of sediments are highly variable. Coarse silts are shown to be purely conductive, producing temperature increases of >10 °C up to 40 cm from the source of 60 °C above ambient; fine sands demonstrate a transition from conductive to convective heat transfer between cf. 20 and 36 °C above ambient, with >10 °C heat increases occurring over a metre from the source of 55 °C above ambient; and very coarse sands exhibit dominantly convective heat transfer even at very low (cf. 7 °C) operating temperatures and reaching temperatures of up to 18 °C above ambient at a metre from the source at surface temperatures of only 18 °C. These findings are important for the surrounding near-surface environments experiencing such high temperatures and may have significant implications for chemical and physical processes operating at the grain and subgrain scale; biological activity at both microfaunal and macrofaunal levels; and indeed the operational performance of the cables themselves, as convective heat transport would increase cable current ratings, something neglected in existing standards.

DC and AC conductivity properties of bovine dentine hydroxyapatite (BDHA)

NASA Astrophysics Data System (ADS)

Dumludag, F.; Gunduz, O.; Kılıc, O.; Ekren, N.; Kalkandelen, C.; Ozbek, B.; Oktar, F. N.

2017-12-01

Bovine dentine bio-waste may be used as a potential natural source of hydroxyapatite (BDHA), thus extraction of bovine dentin hydroxyapatite (BDHA) from bio-waste is significantly important to fabricate in a simple, economically and environmentally preferable. DC and AC conductivity properties of BDHA were investigated depending on sintering temperature (1000ºC - 1300°C) in air and vacuum (<10-2 mbar) ambient at room temperature. DC conductivity measurements performed between -1 and 1 V. AC conductivity measurements performed in the frequency range of 40 Hz - 100 kHz. DC conductivity results showed that dc conductivity values of the BDHA decrease with increasing sintering temperature in air ambient. It is not observed remarkable/systematic behavior for ac conductivity depending on sintering temperature.

A method to measure internal stray radiation of cryogenic infrared imaging systems under various ambient temperatures

NASA Astrophysics Data System (ADS)

Tian, Qijie; Chang, Songtao; Li, Zhou; He, Fengyun; Qiao, Yanfeng

2017-03-01

The suppression level of internal stray radiation is a key criterion for infrared imaging systems, especially for high-precision cryogenic infrared imaging systems. To achieve accurate measurement for internal stray radiation of cryogenic infrared imaging systems under various ambient temperatures, a measurement method, which is based on radiometric calibration, is presented in this paper. First of all, the calibration formula is deduced considering the integration time, and the effect of ambient temperature on internal stray radiation is further analyzed in detail. Then, an approach is proposed to measure the internal stray radiation of cryogenic infrared imaging systems under various ambient temperatures. By calibrating the system under two ambient temperatures, the quantitative relation between the internal stray radiation and the ambient temperature can be acquired, and then the internal stray radiation of the cryogenic infrared imaging system under various ambient temperatures can be calculated. Finally, several experiments are performed in a chamber with controllable inside temperatures to evaluate the effectiveness of the proposed method. Experimental results indicate that the proposed method can be used to measure internal stray radiation with high accuracy at various ambient temperatures and integration times. The proposed method has some advantages, such as simple implementation and the capability of high-precision measurement. The measurement results can be used to guide the stray radiation suppression and to test whether the internal stray radiation suppression performance meets the requirement or not.

The association between ambient temperature and children's lung function in Baotou, China

NASA Astrophysics Data System (ADS)

Li, Shanshan; Guo, Yuming; Williams, Gail; Baker, Peter; Ye, Xiaofang; Madaniyazi, Lina; Kim, Dae-Seon; Pan, Xiaochuan

2015-07-01

The objective of this study is to examine the association between ambient temperature and children's lung function in Baotou, China. We recruited 315 children (8-12 years) from Baotou, China in the spring of 2004, 2005, and 2006. They performed three successive forced expiratory measurements three times daily (morning, noon, and evening) for about 5 weeks. The highest peak expiratory flow (PEF) was recorded for each session. Daily data on ambient temperature, relative humidity, and air pollution were monitored during the same period. Mixed models with a distributed lag structure were used to examine the effects of temperature on lung function while adjusting for individual characteristics and environmental factors. Low temperatures were significantly associated with decreases in PEF. The effects lasted for lag 0-2 days. For all participants, the cumulative effect estimates (lag 0-2 days) were -1.44 (-1.93, -0.94) L/min, -1.39 (-1.92, -0.86) L/min, -1.40 (-1.97, -0.82) L/min, and -1.28 (-1.69, -0.88) L/min for morning, noon, evening, and daily mean PEF, respectively, associated with 1 °C decrease in daily mean temperature. Generally, the effects of temperature were slightly stronger in boys than in girls for noon, evening, and daily mean PEF, while the effects were stronger in girls for morning PEF. PM2.5 had joint effects with temperature on children's PEF. Higher PM2.5 increased the impacts of low temperature. Low ambient temperatures are associated with lower lung function in children in Baotou, China. Preventive health policies will be required for protecting children from the cold weather.

Impact of Ambient Temperature on Hyperthermia Induced by (±)3,4-Methylenedioxymethamphetamine in Rhesus Macaques

PubMed Central

Von Huben, Stefani N.; Lay, Christopher C.; Crean, Rebecca D.; Davis, Sophia A.; Katner, Simon N.; Taffe, Michael A.

2007-01-01

The ambient temperature (TA) under which rodents are exposed to (±)3,4-methylenedioxymethamphetamine (MDMA) affects the direction and magnitude of the body temperature response, and the degree of hypo/hyperthermia generated in subjects can modify the severity of lasting brain changes in “neurotoxicity” models. The thermoregulatory effects of MDMA have not been well described in nonhuman primates and it is unknown if TA has the potential to affect acute hyperthermia and therefore other lasting consequences of MDMA. The objective of this study was to determine if the temperature alteration produced by MDMA in nonhuman primates depends on TA as it does in rats and mice. Body temperature and spontaneous home cage activity were monitored continuously in six male rhesus monkeys via radiotelemetry. The subjects were challenged intramuscularly with 0.56-2.4 mg/kg (±)MDMA under each of three TA conditions (18°C, 24°C, 30°C) in a randomized order. Temperature was significantly elevated following injection with all doses of MDMA under each ambient temperature. The magnitude of mean temperature change was ~1°C in most conditions suggesting a closely controlled thermoregulatory response in monkeys across a range of doses and ambient temperatures. Activity levels were generally suppressed by MDMA, however a 50% increase over vehicle was observed after 0.56 MDMA under the 30°C condition. It is concluded that MDMA produces very a similar degree of hyperthermia in rhesus monkeys across a range of TA conditions which result in hypothermia or exaggerated hyperthermia in rodents. Monkey temperature responses to MDMA appear to be more similar to humans than to rodents and therefore the monkey may offer an improved model of effects related to MDMA-induced hyperthermia. PMID:16641942

Increased ambient air temperature alters the severity of soil water repellency

NASA Astrophysics Data System (ADS)

van Keulen, Geertje; Sinclair, Kat; Hallin, Ingrid; Doerr, Stefan; Urbanek, Emilia; Quinn, Gerry; Matthews, Peter; Dudley, Ed; Francis, Lewis; Gazze, S. Andrea; Whalley, Richard

2017-04-01

Soil repellency, the inability of soils to wet readily, has detrimental environmental impacts such as increased runoff, erosion and flooding, reduced biomass production, inefficient use of irrigation water and preferential leaching of pollutants. Its impacts may exacerbate (summer) flood risks associated with more extreme drought and precipitation events. In this study we have tested the hypothesis that transitions between hydrophobic and hydrophilic soil particle surface characteristics, in conjunction with soil structural properties, strongly influence the hydrological behaviour of UK soils under current and predicted UK climatic conditions. We have addressed the hypothesis by applying different ambient air temperatures under controlled conditions to simulate the effect of predicted UK climatic conditions on the wettability of soils prone to develop repellency at different severities. Three UK silt-loam soils under permanent vegetation were selected for controlled soil perturbation studies. The soils were chosen based on the severity of hydrophobicity that can be achieved in the field: severe to extreme (Cefn Bryn, Gower, Wales), intermediate to severe (National Botanical Garden, Wales), and subcritical (Park Grass, Rothamsted Research near London). The latter is already highly characterised so was also used as a control. Soils were fully saturated with water and then allowed to dry out gradually upon exposure to controlled laboratory conditions. Soils were allowed to adapt for a few hours to a new temperature prior to initiation of the controlled experiments. Soil wettability was determined at highly regular intervals by measuring water droplet penetration times. Samples were collected at four time points: fully wettable, just prior to and after the critical soil moisture concentrations (CSC), and upon reaching air dryness (to constant weight), for further (ultra)metaproteomic and nanomechanical studies to allow integration of bulk soil characterisations with functional expression and nanoscale studies to generate deep mechanistic understanding of the roles of microbes in soil ecosystems. Our controlled soil pertubation studies have shown that an increase in ambient temperature has consistently affected the severity of soil water repellency. Surprisingly, a higher ambient air temperature impacts soils that in the field develop subcritical and extreme repellency, differently under controlled laboratory conditions. We will discuss the impact of these results in relation to predicted UK climatic conditions. Soil metaproteomics will provide mechanistic insight at the molecular level whether differential microbial adaptation is correlated with the apparent different response to a higher ambient air temperature.

Improving turbine performance by cooling inlet air using a waste heat powered ejector refrigerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kowalski, G.J.

1996-12-31

Stationary turbines are used to produce electricity in many areas of the world. Their performance is adversely affected by high ambient temperatures. Several means of reducing the turbine inlet temperature (offpeak water chiller and ice storage and absorption refrigeration systems) are being proposed as a means of increasing turbine output. In the present investigation the feasibility of increasing turbine output power by using its exhaust gases to power an ejector refrigeration system is demonstrated. The advantages of the ejector refrigeration are: it operates on a non-CFC fluid, its small number of moving parts and its small size. The analysis focusesmore » on United Technologies FT4 turbine with a base load output of 21.6 MW. It is demonstrated that the proposed system can decrease the turbine inlet temperature from 296.2 K to 277.6 K which increases the turbine output by 12.8% during periods of high ambient temperature and improves yearly averaged power output by 5.5% in a temperature climate. It is shown that the energy in the turbine exhaust has the potential of producing additional cooling beyond that required to reduce the inlet temperature.« less

The influence of temperature and photoperiod on the timing of brood onset in hibernating honey bee colonies

PubMed Central

Härtel, Stephan; Steffan-Dewenter, Ingolf

2018-01-01

In order to save resources, honey bee (Apis mellifera) colonies in the temperate zones stop brood rearing during winter. Brood rearing is resumed in late winter to build up a sufficient worker force that allows to exploit floral resources in upcoming spring. The timing of brood onset in hibernating colonies is crucial and a premature brood onset could lead to an early depletion of energy reservoirs. However, the mechanisms underlying the timing of brood onset and potential risks of mistiming in the course of ongoing climate change are not well understood. To assess the relative importance of ambient temperature and photoperiod as potential regulating factors for brood rearing activity in hibernating colonies, we overwintered 24 honey bee colonies within environmental chambers. The colonies were assigned to two different temperature treatments and three different photoperiod treatments to disentangle the individual and interacting effects of temperature and photoperiod. Tracking in-hive temperature as indicator for brood rearing activity revealed that increasing ambient temperature triggered brood onset. Under cold conditions, photoperiod alone did not affect brood onset, but the light regime altered the impact of higher ambient temperature on brood rearing activity. Further the number of brood rearing colonies increased with elapsed time which suggests the involvement of an internal clock. We conclude that timing of brood onset in late winter is mainly driven by temperature but modulated by photoperiod. Climate warming might change the interplay of these factors and result in mismatches of brood phenology and environmental conditions. PMID:29844964

The compressive behaviour and constitutive equation of polyimide foam in wide strain rate and temperature

NASA Astrophysics Data System (ADS)

Yoshimoto, Akifumi; Kobayashi, Hidetoshi; Horikawa, Keitaro; Tanigaki, Kenichi

2015-09-01

These days, polymer foams, such as polyurethane foam and polystyrene foam, are used in various situations as a thermal insulator or shock absorber. In general, however, their strength is insufficient in high temperature environments because of their low glass transition temperature. Polyimide is a polymer which has a higher glass transition temperature and high strength. Its mechanical properties do not vary greatly, even in low temperature environments. Therefore, polyimide foam is expected to be used in the aerospace industry. Thus, the constitutive equation of polyimide foam that can be applied across a wide range of strain rates and ambient temperature is very useful. In this study, a series of compression tests at various strain rates, from 10-3 to 103 s-1 were carried out in order to examine the effect of strain rate on the compressive properties of polyimide foam. The flow stress of polyimide foam increased rapidly at dynamic strain rates. The effect of ambient temperature on the properties of polyimide foam was also investigated at temperature from - 190 °C to 270°∘C. The flow stress decreased with increasing temperature.

Timbal muscle physiology in the endothermic cicada Tibicen winnemanna (Homoptera: Cicadidae).

PubMed

Sanborn, A F

2001-08-01

The operative muscle temperature and contraction kinetics are described for the endothermic cicada Tibicen winnemanna (Davis). Measurements of timbal muscle temperature in the field demonstrate that timbal muscle temperature is elevated above ambient temperature during activity. Timbal muscle temperature increases as the acoustic output progresses from a 'warm-up' buzz (27.9-29.7 degrees C) to full song production (36.3-39.5 degrees C). Mean muscle-ambient temperature difference increases from 5.8 degrees C in buzzing animals to 13.1 degrees C in animals producing a full calling song. Twitch rise time and onset to 50% relaxation time decrease while tension production increases with increasing temperature to 40 degrees C. Mean force production at 20 degrees C was determined to be 0.22+/-0.06 N/cm(2). The characteristics of T. winnemanna muscle are similar to those reported in other cicada species. Analysis of the songs produced by animals with one timbal destroyed and the sounds produced by mechanical manipulation suggest that the timbals alternately contract and relax in the sequence IN(1)-IN(2)-OUT(1)-OUT(2). Measurements of the inferred period of muscle contraction from song recordings and the contraction kinetics of isolated timbal muscles measured in the laboratory show that the temperature of the timbal muscle must be elevated in order for the cicada to be able to produce the calling song.

Long-Term Ambient Temperature and Externalizing Behaviors in Adolescents.

PubMed

Younan, Diana; Li, Lianfa; Tuvblad, Catherine; Wu, Jun; Lurmann, Fred; Franklin, Meredith; Berhane, Kiros; McConnell, Rob; Wu, Anna H; Baker, Laura A; Chen, Jiu-Chiuan

2018-05-21

The climate-violence relationship has been debated for decades, and yet most of the supportive evidence came from ecological or cross-sectional analyses with very limited long-term exposure data. We conducted an individual-level, longitudinal study to investigate the association between ambient temperature and externalizing behaviors of urban-dwelling adolescents. Participants (n = 1,287) of the Risk Factors for Antisocial Behavior Study were examined in 2000-2012 (aged 9-18 years) with repeated assessments of their externalizing behaviors (aggression; delinquency). Ambient temperature data were obtained from the local Meteorological Information System. In adjusted multi-level models, aggressive behaviors significantly increased with rising average temperatures (per 1°C-increment) in preceding 1-3 years (β = 0.23, 95% CI: 0.00, 0.46; β = 0.35, 95% CI: 0.06, 0.63; β = 0.41, 95% CI: 0.08, 0.74; respectively), equivalent to 1.5-3 years of delay in age-related behavioral maturation. These associations were slightly stronger among girls and families of lower socioeconomic status, but greatly diminished in neighborhoods with higher greenspace. No significant associations were found with delinquency. Our study provides the first individual-level epidemiologic evidence supporting the adverse association of long-term ambient temperature and aggression. Similar approaches to studying meteorology and violent crimes may further inform scientific debates on climate change and collective violence.

Cold stress aggravates inflammatory responses in an LPS-induced mouse model of acute lung injury

NASA Astrophysics Data System (ADS)

Joo, Su-Yeon; Park, Mi-Ju; Kim, Kyun-Ha; Choi, Hee-Jung; Chung, Tae-Wook; Kim, Yong Jin; Kim, Joung Hee; Kim, Keuk-Jun; Joo, Myungsoo; Ha, Ki-Tae

2016-08-01

Although the relationship between environmental cold temperature and susceptibility to respiratory infection is generally accepted, the effect of ambient cold temperature on host reactivity in lung inflammation has not been fully studied. To examine the function of ambient cold temperature on lung inflammation, mice were exposed to 4 °C for 8 h each day for 14 days. In the lungs of mice exposed to cold stress, inflammatory cells in bronchoalveolar lavage (BAL) fluid and lung tissues were slightly increased by about twofold. However, the structures of pulmonary epithelial cells were kept within normal limits. Next, we examined the effect of cold stress on the inflammatory responses in a lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model. The infiltration of neutrophils and inflammation of lung tissue determined by histology were significantly increased by exposure to ambient cold temperature. In addition, the production of pro-inflammatory cytokines including interleukin (IL)-12, IL-17, and monokine induced by gamma interferon (MIG) was elevated by exposure to cold stress. Therefore, we suggest that cold stress is a factor that exacerbates lung inflammation including ALI. To our knowledge, this is the first report on the relationship between cold stress and severity of lung inflammation.

Incubation Temperature during Fetal Development Influences Morphophysiological Characteristics and Preferred Ambient Temperature of Chicken Hatchlings

PubMed Central

Morita, Viviane de Souza; de Almeida, Vitor Rosa; Matos, João Batista; Vicentini, Tamiris Iara; van den Brand, Henry; Boleli, Isabel Cristina

2016-01-01

Skin and feather characteristics, which play a critical role in body temperature maintenance, can be affected by incubation circumstances, such as incubation temperature. However, no study to date has assessed the influence of incubation temperature during the fetal stage on morphometric characteristics and vascular development of the skin, feather characteristics, and their relationship to hormone levels and preferred temperature in later life in chickens. Broiler breeder eggs were exposed to low (36°C), control (37.5°C), or high (39°C) temperatures (treatments LT, CK, and HT, respectively) from day 13 of incubation onward, because it is known that the endocrine axes are already established at this time. During this period, eggshell temperature of HT eggs (38.8±0.33°C) was higher than of LT (37.4±0.08°C) and CK eggs (37.8 ±0.15°C). The difference between eggshell and incubator air temperature diminished with the increasing incubation temperature, and was approximately zero for HT. HT hatchlings had higher surface temperature on the head, neck, and back, and thinner and more vascularized skin than did CK and LT hatchlings. No differences were found among treatments for body weight, total feather weight, number and length of barbs, barbule length, and plasma T4 concentration. LT hatchlings showed lower plasma T3 and GH, as well as lower T3/T4 ratio and decreased vascularity in the neck, back, and thigh skin compared to CK hatchlings. On the other hand, HT hatchlings had decreased skin thickness and increased vascularity, and preferred a higher ambient temperature compared to CK and HT hatchlings. In addition, for all treatments, surface temperature on the head was higher than of the other body regions. We conclude that changes in skin thickness and vascularity, as well as changes in thyroid and growth hormone levels, are the result of embryonic strategies to cope with higher or lower than normal incubation temperatures. Additionally exposure to increased temperature during incubation is an environmental factor that can exert early-life influence on ambient temperature preference of broiler hatchlings in later life. PMID:27183111

Incubation Temperature during Fetal Development Influences Morphophysiological Characteristics and Preferred Ambient Temperature of Chicken Hatchlings.

PubMed

Morita, Viviane de Souza; Almeida, Vitor Rosa de; Matos, João Batista; Vicentini, Tamiris Iara; van den Brand, Henry; Boleli, Isabel Cristina

2016-01-01

Skin and feather characteristics, which play a critical role in body temperature maintenance, can be affected by incubation circumstances, such as incubation temperature. However, no study to date has assessed the influence of incubation temperature during the fetal stage on morphometric characteristics and vascular development of the skin, feather characteristics, and their relationship to hormone levels and preferred temperature in later life in chickens. Broiler breeder eggs were exposed to low (36°C), control (37.5°C), or high (39°C) temperatures (treatments LT, CK, and HT, respectively) from day 13 of incubation onward, because it is known that the endocrine axes are already established at this time. During this period, eggshell temperature of HT eggs (38.8±0.33°C) was higher than of LT (37.4±0.08°C) and CK eggs (37.8 ±0.15°C). The difference between eggshell and incubator air temperature diminished with the increasing incubation temperature, and was approximately zero for HT. HT hatchlings had higher surface temperature on the head, neck, and back, and thinner and more vascularized skin than did CK and LT hatchlings. No differences were found among treatments for body weight, total feather weight, number and length of barbs, barbule length, and plasma T4 concentration. LT hatchlings showed lower plasma T3 and GH, as well as lower T3/T4 ratio and decreased vascularity in the neck, back, and thigh skin compared to CK hatchlings. On the other hand, HT hatchlings had decreased skin thickness and increased vascularity, and preferred a higher ambient temperature compared to CK and HT hatchlings. In addition, for all treatments, surface temperature on the head was higher than of the other body regions. We conclude that changes in skin thickness and vascularity, as well as changes in thyroid and growth hormone levels, are the result of embryonic strategies to cope with higher or lower than normal incubation temperatures. Additionally exposure to increased temperature during incubation is an environmental factor that can exert early-life influence on ambient temperature preference of broiler hatchlings in later life.

Effect of ambient temperature and sodium bicarbonate supplementation on water and electrolyte balances in dry and lactating Holstein cows.

PubMed

Khelil-Arfa, H; Faverdin, P; Boudon, A

2014-01-01

The aim of this study was to quantify the effect of the interaction between 2 constant ambient temperatures [thermoneutrality (TN; 15°C) and high temperature (HT; 28°C)] and 2 levels of Na bicarbonate supplementation [calculated to provide diet Na contents of 0.20%DM (Na-) and 0.50%DM (Na+)] on water partitioning in dairy cows. Treatments were compared on 4 dry and 4mid-lactation Holstein cows according to 2 Latin squares (1 for each physiological stage) over the course of 4 periods of 15d. Diets consisted of a total mixed ration based on maize silage. Dry cows were restricted to their protein and energy requirements, whereas lactating cows were fed ad libitum. The daily average temperature-humidity index was 59.4 for TN and 73.2 for HT. Lactating and dry cows had higher vaginal temperatures at HT than at TN, but the increase was more pronounced in lactating cows (+1.05 vs. +0.12°C for vaginal temperature, respectively). Dry matter intake (DMI) of lactating cows decreased by 2.3kg/d at HT. Free water intake (FWI) and estimated volume of water lost to evaporation increased at HT in both lactating and dry cows; no interactions were observed between temperature and physiological stage. When expressed as a proportion of DMI, the increase in evaporation that occurred with increasing temperature was completely compensated for by an increase in FWI for both physiological stages. The urinary water excretion increased slightly at HT in lactating cows but not in dry cows, which may be related to the low chloride content of the offered diet. High Na supplementation increased DMI slightly in lactating cows, but milk yield was not affected. Sodium supplementation did not limit the decrease in DMI observed in lactating cows at HT; this observation is likely due to the high diet electrolyte balance of the offered diets. Sodium supplementation increased FWI in lactating cows and urinary flow in both physiological states. The interaction between ambient temperature and Na supplementation did not affect either water intake or water evaporation. This study demonstrates that the development of predictive models for water intake that include environmental variables could be based on mechanistic models of evaporation. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Analysis of high injection pressure and ambient temperature on biodiesel spray characteristics using computational fluid dynamics

NASA Astrophysics Data System (ADS)

Hashim, Akasha; Khalid, Amir; Jaat, Norrizam; Sapit, Azwan; Razali, Azahari; Nizam, Akmal

2017-09-01

Efficiency of combustion engines are highly affected by the formation of air-fuel mixture prior to ignition and combustion process. This research investigate the mixture formation and spray characteristics of biodiesel blends under variant in high ambient and injection conditions using Computational Fluid Dynamics (CFD). The spray characteristics such as spray penetration length, spray angle and fluid flow were observe under various operating conditions. Results show that increase in injection pressure increases the spray penetration length for both biodiesel and diesel. Results also indicate that higher spray angle of biodiesel can be seen as the injection pressure increases. This study concludes that spray characteristics of biodiesel blend is greatly affected by the injection and ambient conditions.

Photoperiod and fur lengths in the arctic fox ( Alopex lagopus L.)

NASA Astrophysics Data System (ADS)

Underwood, L. S.; Reynolds, Patricia

1980-03-01

Pelage is seasonally dimorphic in the Arctic fox. During the winter, fur lengths for this species are nearly double similar values taken during the summer season. Considerable site-specific differences in fur length are noted. In general, body sites which are exposed to the environment when an Arctic fox lies in a curled position show greater fur lengths in all seasons and greater seasonal variations than body sites that are more protected during rest. Well-furred sites may tend to conserve heat during periods of inactivity, and scantily furred sites may tend to dissipate heat during periods of exercise. The growth of winter fur may compensate for the severe cold of the arctic winter. Changes in fur lengths indicate a definite pattern in spite of individual variations. During the fall months, fur lengths seem to lag behind an increasing body-to-ambient temperature gradient. Both body-to-ambient temperature gradients and fur lengths peak during December through February. From March through June, gradual environmental warming is accompanied by a decrease in average fur lengths. Thus, there appears to be a remarkable parallel between the body-to-ambient temperature gradient and the fur lengths. The growth of fur in the Arctic fox parallels annual changes in ambient temperature and photoperiod.

14 CFR 25.1527 - Ambient air temperature and operating altitude.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ambient air temperature and operating... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Operating Limitations and Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of...

Ambient temperature and emergency room admissions for acute coronary syndrome in Taiwan

NASA Astrophysics Data System (ADS)

Liang, Wen-Miin; Liu, Wen-Pin; Chou, Sze-Yuan; Kuo, Hsien-Wen

2008-01-01

Acute coronary syndrome (ACS) is an important public health problem around the world. Since there is a considerable seasonal fluctuation in the incidence of ACS, climatic temperature may have an impact on the onset of this disease. The objective of this study was to assess the relationship between the average daily temperature, diurnal temperature range and emergency room (ER) admissions for ACS in an ER in Taichung City, Taiwan. A longitudinal study was conducted which assessed the correlation of the average daily temperature and the diurnal temperature range to ACS admissions to the ER of the city’s largest hospital. Daily ER admissions for ACS and ambient temperature were collected from 1 January 2000 to 31 March 2003. The Poisson regression model was used in the analysis after adjusting for the effects of holiday, season, and air pollutant concentrations. The results showed that there was a negative significant association between the average daily temperature and ER admissions for ACS. ACS admissions to the ER increased 30% to 70% when the average daily temperature was lower than 26.2°C. A positive association between the diurnal temperature range and ACS admissions was also noted. ACS admissions increased 15% when the diurnal temperature range was over 8.3°C. The data indicate that patients suffering from cardiovascular disease must be made aware of the increased risk posed by lower temperatures and larger changes in temperature. Hospitals and ERs should take into account the increased demand of specific facilities during colder weather and wider temperature variations.

40 CFR 86.605-88 - Maintenance of records; submittal of information.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., pressure increase across the pump, and the temperature set point of the temperature control system. (2... samples are being collected. (3) Humidity of dilution air. (4) Manufacturer, model, type and serial number..., ambient temperature and humidity. (2) Data and time of day. (ii) In lieu of recording test equipment...

40 CFR 86.605-88 - Maintenance of records; submittal of information.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., pressure increase across the pump, and the temperature set point of the temperature control system. (2... samples are being collected. (3) Humidity of dilution air. (4) Manufacturer, model, type and serial number..., ambient temperature and humidity. (2) Data and time of day. (ii) In lieu of recording test equipment...

40 CFR 86.605-88 - Maintenance of records; submittal of information.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., pressure increase across the pump, and the temperature set point of the temperature control system. (2... samples are being collected. (3) Humidity of dilution air. (4) Manufacturer, model, type and serial number..., ambient temperature and humidity. (2) Data and time of day. (ii) In lieu of recording test equipment...

Evidence that higher [CO2] increases tree growth sensitivity to temperature: a comparison of modern and paleo oaks

EPA Science Inventory

Aim: To test the growth-sensitivity to temperature under different ambient CO2 concentrations, we determined paleo tree growth rates as they relate to variation in temperature during the last deglacial period, and compare these to modern tree growth rates as they relate to spatia...

Temperature-dependent regulation of blood distribution in snakes.

PubMed

Amiel, Joshua J; Chua, Beverly; Wassersug, Richard J; Jones, David R

2011-05-01

Regional control of blood flow is often suggested as a mechanism for fine thermoregulatory adjustments in snakes. However, the flow of blood to different body regions at various temperatures has never been visualized to confirm this mechanism. We used (99m)technetium-labelled macroaggregated albumin ((99m)Tc-MAA), a radioactive tracer, to follow the flow of blood through the bodies of garter snakes (Thamnophis sirtalis) near their thermal maxima and minima. We injected snakes with(99m)Tc-MAA at cold (6-8°C) and hot (27-32°C) temperatures and imaged them using a gamma scanner. At cold ambient temperatures, snakes significantly reduced the blood flow to their tails and significantly increased the blood flow to their heads. Conversely, at hot ambient temperatures, snakes significantly increased the blood flow to their tails and significantly reduced the blood flow to their heads. This confirms that snakes are able to use differential blood distribution to regulate temperature. Our images confirm that snakes use regional control of blood flow as a means of thermoregulation and that vasomotor control of vascular beds is likely to be the mechanism of control.

Electrical bushing for a superconductor element

DOEpatents

Mirebeau, Pierre; Lallouet, Nicolas; Delplace, Sebastien; Lapierre, Regis

2010-05-04

The invention relates to an electrical bushing serving to make a connection at ambient temperature to a superconductor element situated in an enclosure at cryogenic temperature. The electrical bushing passes successively through an enclosure at intermediate temperature between ambient temperature and cryogenic temperature, and an enclosure at ambient temperature, and it comprises a central electrical conductor surrounded by an electrically insulating sheath. According to the invention, an electrically conductive screen connected to ground potential surrounds the insulating sheath over a section that extends from the end of the bushing that is in contact with the enclosure at cryogenic temperature at least as far as the junction between the enclosure at intermediate temperature and the enclosure at ambient temperature. The invention is more particularly applicable to making a connection to a superconductor cable.

Distinct vasopressin content in the hypothalamic supraoptic and paraventricular nucleus of rats exposed to low and high ambient temperature.

PubMed

Jasnic, N; Dakic, T; Bataveljic, D; Vujovic, P; Lakic, I; Jevdjovic, T; Djurasevic, S; Djordjevic, J

2015-08-01

Both high and low ambient temperature represent thermal stressors that, among other physiological responses, induce activation of the hypothalamic-pituitary-adrenal (HPA) axis and secretion of arginine-vasopressin (AVP). The exposure to heat also leads to disturbance of osmotic homeostasis. Since AVP, in addition to its well-known peripheral effects, has long been recognized as a hormone involved in the modulation of HPA axis activity, the aim of the present study was to elucidate the hypothalamic AVP amount in the acutely heat/cold exposed rats. Rats were exposed to high (+38°C) or low (+4°C) ambient temperature for 60min. Western blot was employed for determining hypothalamic AVP levels, and the difference in its content between supraoptic (SON) and paraventricular nucleus (PVN) was detected using immunohistochemical analysis. The results showed that exposure to both high and low ambient temperature increased hypothalamic AVP levels, although the increment was higher under heat conditions. On the other hand, patterns of AVP level changes in PVN and SON were stressor-specific, given that exposure to cold increased the AVP level in both nuclei, while heat exposure affected the PVN AVP content alone. In conclusion, our results revealed that cold and heat stress influence hypothalamic AVP amount with different intensity. Moreover, different pattern of AVP amount changes in the PVN and SON indicates a role of this hormone not only in response to heat as an osmotic/physical threat, but to the non-osmotic stressors as well. Copyright © 2015 Elsevier Ltd. All rights reserved.

O2 consumption and heart rate in developing zebrafish (Danio rerio): influence of temperature and ambient O2.

PubMed

Barrionuevo, W R; Burggren, W W

1999-02-01

Body mass, length, oxygen consumption (MO2) and heart rate (fH) were measured in "embryos" (prior to hatching), "larvae" (days 10-20), "juveniles" (days 30-70 in 10-day intervals), and "adults" (day 100) of the zebrafish Danio rerio. Fish were chronically reared at either 25, 28, or 31 degreesC and then acutely exposed to hypoxia at different developmental stages. We hypothesized that at any given rearing and measurement temperature, D. rerio would maintain MO2 at lower ambient PO2 [i.e., have a lower critical partial pressure (Pcrit)] as development progressed and that at any given developmental stage individuals reared and measured at higher temperatures would show a more pronounced hypoxic bradycardia. MO2 in normoxic fish at 28 degreesC peaked at approximately 40 micromol. g-1. h-1 at day 10, thereafter falling to 4-5 micromol. g-1. h-1 at day 100. The Q10 for MO2 was 4-5 in embryos, falling to 2-3 from day 10 to day 60 and rising again to 4-5 at day 100. Pcrit at 28 degreesC was approximately 80 mmHg in embryos but decreased sharply to 20 mmHg at 100 days, supporting the hypothesis that more mature fish would be better able to oxygen regulate to lower ambient PO2 levels. Pcrit increased sharply with measurement temperature. Heart rate (fH) at 28 degreesC increased from about 125 beats/min in embryos to a peak of approximately 175 beats/min at days 10-30 and then fell to approximately 130 beats/min by day 100. Unlike for MO2, the Q10 for fH was more constant at 1.2-2.5 throughout development. Hypoxic exposure at any temperature had no effect on fH until approximately day 30, after which time a hypoxic bradycardia was evident. As evident for MO2, the bradycardia in older larvae was more profound at higher temperatures. On the assumption that bradycardia is indicative of hypoxic stress, the increasing prevalence of a hypoxic bradycardia in older, warmer individuals supports the hypothesis that increasing hypoxic susceptibility with development would be exacerbated by increasing temperature. Collectively, these data indicate that the ability to regulate MO2 and fH in response to the compounding demands of increased temperature and/or decreased oxygen availability first develops after approximately 20 days in D. rerio and, thereafter, the ability to maintain MO2 in the face of ambient hypoxia progressively builds through to adulthood. Additionally, the temperature responses of metabolism and heart rate differ substantially at different phases of development, suggesting a loose coupling between the respiratory and cardiovascular systems, at least early in development.

Presence and persistence of a highly ordered lipid phase state in the avian stratum corneum.

PubMed

Champagne, Alex M; Pigg, Victoria A; Allen, Heather C; Williams, Joseph B

2018-06-07

To survive high temperatures in a terrestrial environment, animals must effectively balance evaporative heat loss and water conservation. In passerine birds, cutaneous water loss (CWL) is the primary avenue of water loss at thermoneutral temperatures and increases slightly as ambient temperature increases, indicating a change in the permeability of the skin. In the stratum corneum (SC), the outermost layer of the skin, lipids arranged in layers called lamellae serve as the primary barrier to CWL in birds. The permeability of these lamellae depends in large part on the ability of lipid molecules to pack closely together in an ordered orthorhombic phase state. However, as temperature increases, lipids of the SC become more disordered, and may pack in more permeable hexagonal or liquid crystalline phase states. In this study, we used Fourier transform infrared spectroscopy to monitor the phase state of lipids in the SC of house sparrows ( Passer domesticus ) at skin temperatures ranging from 25 to 50°C. As temperature increased, lipids became slightly more disordered, but remained predominantly in the orthorhombic phase, consistent with the small increase in CWL observed in house sparrows as ambient temperature increases. These results differ considerably from studies on mammalian SC, which find a predominantly hexagonal arrangement of lipids at temperatures above 37°C, and the increased order in avian SC may be explained by longer lipid chain length, scarcity of cholesterol and the presence of cerebrosides. Our results lend further insight into the arrangement and packing of individual lipid molecules in avian SC. © 2018. Published by The Company of Biologists Ltd.

Effects of hot, humid weather on milk temperature, dry matter intake, and milk yield of lactating dairy cows.

PubMed

West, J W; Mullinix, B G; Bernard, J K

2003-01-01

Lactating cows were exposed to moderate and hot, humid weather to determine the effect of increasing ambient temperature, relative humidity, or temperature-humidity index (THI) on intake, milk yield, and milk temperature. Minimum and maximum temperatures averaged 17.9 and 29.5 degrees C (cool period) and 22.5 and 34.4 degrees C (hot period), and minimum and maximum THI averaged 63.8 and 76.6 (cool period) and 72.1 and 83.6 (hot period). Environmental conditions had minor effects on intake and milk yield during the cool period. During the hot period, the THI 2 d earlier and mean air temperature 2 d earlier had the greatest impact on milk yield and DMI, respectively. Both breeds maintained milk temperature within normal ranges during the cool period, but Holstein and Jersey p.m. milk temperatures averaged 39.6 and 39.2 degrees C during the hot period. Current day mean air temperature during the hot period had the greatest impact on cow p.m. milk temperature, and minimum air temperature had the greatest influence on a.m. milk temperature. Dry matter intake and milk yield declined linearly with respective increases in air temperature or THI during the hot period and milk temperature increased linearly with increasing air temperature. Dry matter intake and milk yield both exhibited a curvilinear relationship with milk temperature. Environmental modifications should target the effects of high temperatures on cow body temperature and should modify the environment at critical times during the day when cows are stressed, including morning hours when ambient temperatures are typically cooler and cows are not assumed to be stressed.

Intercomparison of thermal-optical method with different temperature protocols: Implications from source samples and solvent extraction

NASA Astrophysics Data System (ADS)

Cheng, Yuan; Duan, Feng-kui; He, Ke-bin; Du, Zhen-yu; Zheng, Mei; Ma, Yong-liang

2012-12-01

Three temperature protocols with different peak inert mode temperature (Tpeak-inert) were compared based on source and ambient samples (both untreated and extracted using a mixture of hexane, methylene chloride, and acetone) collected in Beijing, China. The ratio of EC580 (elemental carbon measured by the protocol with a Tpeak-inert of 580 °C; similar hereinafter) to EC850 could be as high as 4.8 for biomass smoke samples whereas the ratio was about 1.0 for diesel and gasoline exhaust samples. The EC580 to EC850 ratio averaged 1.95 ± 0.89 and 1.13 ± 0.20 for the untreated and extracted ambient samples, whereas the EC580 to EC650 ratio of ambient samples was 1.22 ± 0.10 and 1.20 ± 0.12 before and after extraction. It was suggested that there are two competing mechanisms for the effects of Tpeak-inert on the EC results such that when Tpeak-inert is increased, one mechanism tends to decrease EC by increasing the amount of charring whereas the other tends to increase EC through promoting more charring to evolve before native EC. Results from this study showed that EC does not always decrease when increasing the peak inert mode temperature. Moreover, reducing the charring amount could improve the protocols agreement on EC measurements, whereas temperature protocol would not influence the EC results if no charring is formed. This study also demonstrated the benefits of allowing for the OC and EC split occurring in the inert mode when a high Tpeak-inert is used (e.g., 850 °C).

Influence of environmental temperature on prolificacy of pigs.

PubMed

Wettemann, R P; Bazer, F W

1985-01-01

Exposure of male and female pigs to elevated ambient temperatures can result in reduced reproductive efficiency. When boars and gilts are exposed to heat stress, respiratory rates increase to enhance evaporative cooling because minimal sweating occurs. During early pregnancy, gilts are especially susceptible to heat stress. Decreased conception rates and reduced litter size occur when gilts are exposed to elevated ambient temperature during Days 0 to 16 after mating. Concentrations of progesterone in peripheral plasma were reduced during Days 13-19 after mating and luteal function was extended to Day 25 in heat-stressed gilts that did not conceive. Increased concentrations of oestradiol during Day 10 to 12 of heat stress may interfere with normal maternal recognition of pregnancy. Heat stress reduced the amount of embryonic tissue present at Day 16 of pregnancy but the protein synthetic activity of the tissue was not altered. Thus some embryos may be lost and a reduction in litter size may occur. The production of oestrogen by the conceptus and uterus is not altered on Day 16, after exposure to heat stress for the previous 8 days. These studies suggest that heat stress during early pregnancy can alter the reproductive endocrine system, especially the control of luteal function. In addition, heat stress may have a direct effect on embryo or conceptus development. Exposure of boars to elevated ambient temperatures causes reductions in semen quality, sperm output and fertility. About 5 weeks are required for boars to recover from the detrimental effects of heat stress and to produce semen with potential for maximal fertility. Increased temperature has an inhibitory effect on spermatid maturation and on testicular androgen biosynthesis. Improvements in reproductive performance can be achieved by increasing evaporative cooling of boars.

Effect of environmental temperature on sleep, locomotor activity, core body temperature and immune responses of C57BL/6J mice

PubMed Central

Jhaveri, KA; Trammell, RA; Toth, LA

2007-01-01

Ambient temperature exerts a prominent influence on sleep. In rats and humans, low ambient temperatures generally impair sleep, whereas higher temperatures tend to promote sleep. The purpose of the current study was to evaluate sleep patterns and core body temperatures of C57BL/6J mice at ambient temperatures of 22°C, 26°C and 30°C under baseline conditions, after sleep deprivation (SD), and after infection with influenza virus. C57BL/6J mice were surgically implanted with electrodes for recording electroencephalogram (EEG) and electromyogram (EMG) and with intraperitoneal transmitters for recording core body temperature (Tc) and locomotor activity. The data indicate that higher ambient temperatures (26°C and 30°C) promote spontaneous slow wave sleep (SWS) in association with reduced delta wave amplitude during SWS in C57BL/6J mice. Furthermore, higher ambient temperatures also promote recuperative sleep after SD. Thus, in mice, higher ambient temperatures reduced sleep depth under normal conditions, but augmented the recuperative response to sleep loss. Mice infected with influenza virus while maintained at 22 or 26°C developed more SWS, less rapid eye movement sleep, lower locomotor activity and greater hypothermia than did mice maintained at 30°C during infection. In addition, despite equivalent viral titers, mice infected with influenza virus at 30°C showed less leucopenia and lower cytokine induction as compared with 22 and 26°C, respectively, suggesting that less inflammation develops at the higher ambient temperature. PMID:17467232

Physical activity levels of community-dwelling older adults are influenced by winter weather variables.

PubMed

Jones, G R; Brandon, C; Gill, D P

2017-07-01

Winter weather conditions may negatively influence participation of older adults in daily physical activity (PA). Assess the influence of winter meteorological variables, day-time peak ambient temperature, windchill, humidity, and snow accumulation on the ground to accelerometer measured PA values in older adults. 50 community-dwelling older adults (77.4±4.7yrs; range 71-89; 12 females) living in Southwestern Ontario (Latitude 42.9°N Longitude 81.2° W) Canada, wore a waist-borne accelerometer during active waking hours (12h) for 7 consecutive days between February and April 2007. Hourly temperature, windchill, humidity, and snowfall accumulation were obtained from meteorological records and time locked to hourly accelerometer PA values. Regression analysis revealed significant relationships between time of day, ambient daytime high temperature and a humidity for participation in PA. Windchill temperature added no additional influence over PA acclamation already influenced by ambient day-time temperature and the observed variability in PA patterns relative to snow accumulation over the study period was too great to warrant its inclusion in the model. Most PA was completed in the morning hours and increased as the winter month's transitioned to spring (February through April). An equation was developed to adjust for winter weather conditions using temperature, humidity and time of day. Accurate PA assessment during the winter months must account for the ambient daytime high temperatures, humidity, and time of day. These older adults were more physically active during the morning hours and became more active as the winter season transitioned to spring. Copyright © 2017 Elsevier B.V. All rights reserved.

Evidence that higher [CO2] increases tree growth sensitivity to temperature: a comparison of modern and paleo oaks

Treesearch

Steven L. Voelker; Michael C. Stambaugh; J. Renée Brooks; Frederick C. Meinzer; Barbara Lachenbruch; Richard P. Guyette

2017-01-01

To test tree growth-sensitivity to temperature under different ambient CO2 concentrations, we determined stem radial growth rates as they relate to variation in temperature during the last deglacial period, and compare these to modern tree growth rates as they relate to spatial variation in temperature across the modern species distributional...

Ambient temperature and volume of perihematomal edema in acute intracerebral haemorrhage: the INTERACT1 study.

PubMed

Zheng, Danni; Arima, Hisatomi; Heeley, Emma; Karpin, Anne; Yang, Jie; Chalmers, John; Anderson, Craig S

2015-01-01

As no human data exist, we aimed to determine the relation between ambient temperature and volume of perihematomal 'cerebral' edema in acute spontaneous intracerebral haemorrhage (ICH) among Chinese participants of the pilot phase, Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT1). INTERACT1 was a multicenter, open, blind outcome assessed, randomized controlled trial of intensive (systolic target <140 mmHg) vs. guideline-recommended (systolic target <180 mmHg) blood pressure (BP) lowering in 404 patients with acute ICH. Data on ambient temperature (mean, minimum, maximum, and range) on the day of each participant's ICH obtained from China Meteorological Data Sharing Service System were linked to other data including edema volumes. Multivariable regression analyses were performed to evaluate association between ambient temperature and edema volumes. A generalized linear regression model with a generalized estimating equations approach (GEE) was used to assess any association of ambient temperature and change in edema volume over 72 h. A total of 250 of all 384 Chinese participants had complete data that showed positive associations between ambient temperature (mean and minimum temperatures) and edema volumes at each time point over 72 h after hospital admission (all P < 0·05). All temperature parameters except diurnal temperature range were positively associated with edema volume after adjustment for confounding variables (all P < 0·02). An apparent positive association exists between ambient temperature and perihematomal edema volume in acute spontaneous ICH. © 2014 World Stroke Organization.

Thermal Stress and Toxicity | Science Inventory | US EPA

EPA Pesticide Factsheets

Elevating ambient temperature above thermoneutrality exacerbates toxicity of most air pollutants, insecticides, and other toxic chemicals. On the other hand, safety and toxicity testing of toxicants and drugs is usually performed in mice and rats maintained at subthermoneutral temperatures of —22 °C. When exposed to chemical toxicants under these relatively cool conditions, rodents typically undergo a regulated hypothermic response, characterized by preference for cooler ambient temperatures and controlled reduction in core temperature. Reducing core temperature delays the clearance of most toxicants from the body; however, a mild hypothermia also improves recovery and survival from the toxicant. Raising ambient temperature to thermoneutrality and above increases the rate of clearance of the toxicant but also exacerbates toxicity. Furthermore, heat stress combined with work or exercise is likely to worsen toxicity. Body temperature of large mammals, including humans, does not decrease as much in response to exposure to a toxicant. However, heat stress tan nonetheless worsen toxic outcome in humans through a variety of mechanisms. For example, heat-induced sweating and elevation in skin blood flow accelerates uptake of some insecticides. Epidemiological studies suggest that thermal stress may exacerbate the toxicity of airborne pollutants such as ozone and particulate matter. Overall, translating results of studies in rodents to that of humans is a formidable

CARS Temperature Measurements in a Combustion-Heated Supersonic Jet

NASA Technical Reports Server (NTRS)

Tedder, S. A.; Danehy, P. M.; Magnotti, G.; Cutler, A. D.

2009-01-01

Measurements were made in a combustion-heated supersonic axi-symmetric free jet from a nozzle with a diameter of 6.35 cm using dual-pump Coherent Anti-Stokes Raman Spectroscopy (CARS). The resulting mean and standard deviation temperature maps are presented. The temperature results show that the gas temperature on the centerline remains constant for approximately 5 nozzle diameters. As the heated gas mixes with the ambient air further downstream the mean temperature decreases. The standard deviation map shows evidence of the increase of turbulence in the shear layer as the jet proceeds downstream and mixes with the ambient air. The challenges of collecting data in a harsh environment are discussed along with influences to the data. The yield of the data collected is presented and possible improvements to the yield is presented are discussed.

HIgh Temperature Photocatalysis over Semiconductors

NASA Astrophysics Data System (ADS)

Westrich, Thomas A.

Due in large part to in prevalence of solar energy, increasing demand of energy production (from all sources), and the uncertain future of petroleum energy feedstocks, solar energy harvesting and other photochemical systems will play a major role in the developing energy market. This dissertation focuses on a novel photochemical reaction process: high temperature photocatalysis (i.e., photocatalysis conducted above ambient temperatures, T ≥ 100°C). The overarching hypothesis of this process is that photo-generated charge carriers are able to constructively participate in thermo-catalytic chemical reactions, thereby increasing catalytic rates at one temperature, or maintaining catalytic rates at lower temperatures. The photocatalytic oxidation of carbon deposits in an operational hydrocarbon reformer is one envisioned application of high temperature photocatalysis. Carbon build-up during hydrocarbon reforming results in catalyst deactivation, in the worst cases, this was shown to happen in a period of minutes with a liquid hydrocarbon. In the presence of steam, oxygen, and above-ambient temperatures, carbonaceous deposits were photocatalytically oxidized over very long periods (t ≥ 24 hours). This initial experiment exemplified the necessity of a fundamental assessment of high temperature photocatalytic activity. Fundamental understanding of the mechanisms that affect photocatalytic activity as a function of temperatures was achieved using an ethylene photocatalytic oxidation probe reaction. Maximum ethylene photocatalytic oxidation rates were observed between 100 °C and 200 °C; the maximum photocatalytic rates were approximately a factor of 2 larger than photocatalytic rates at ambient temperatures. The loss of photocatalytic activity at temperatures above 200 °C is due to a non-radiative multi-phonon recombination mechanism. Further, it was shown that the fundamental rate of recombination (as a function of temperature) can be effectively modeled as a temperature-dependent quantum efficiency term, and is directly driven by bulk photocatalyst crystal parameters: maximum phonon energy and the number of phonons allowed per unit cell. This analysis extends to multiple photocatalysts and can explain experimental observations of photocatalytic oxidation rates with varied reactant concentrations. Lastly, this dissertation applies this knowledge to a thermo-catalytic reaction (CO-oxidation) using a Au/TiO 2 catalyst. The combined photo/thereto-catalytic reaction showed a 10-25% increase in CO conversion during a temperature programmed reaction experiment.

46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F). [CGD 81-078, 50 FR 21173...

46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F). [CGD 81-078, 50 FR 21173...

46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F). [CGD 81-078, 50 FR 21173...

46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F). [CGD 81-078, 50 FR 21173...

46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F). [CGD 81-078, 50 FR 21173...

Arabian Oryx (Oryx leucoryx) Respond to Increased Ambient Temperatures with a Seasonal Shift in the Timing of Their Daily Inactivity Patterns.

PubMed

Davimes, Joshua G; Alagaili, Abdulaziz N; Gravett, Nadine; Bertelsen, Mads F; Mohammed, Osama B; Ismail, Khairy; Bennett, Nigel C; Manger, Paul R

2016-08-01

The Arabian oryx inhabits an environment where summer ambient temperatures can exceed 40 °C for extended periods of time. While the oryx uses a suite of adaptations that aid survival, the effects of this extreme environment on inactivity are unknown. To determine how the oryx manages inactivity seasonally, we measured the daily rhythm of body temperature and used fine-grain actigraphy, in 10 animals, to reveal when the animals were inactive in relation to ambient temperature and photoperiod. We demonstrate that during the cooler winter months, the oryx was inactive during the cooler parts of the 24-h day (predawn hours), showing a nighttime (nocturnal) inactivity pattern. In contrast, in the warmer summer months, the oryx displayed a bimodal inactivity pattern, with major inactivity bouts (those greater than 1 h) occurring equally during both the coolest part of the night (predawn hours) and the warmest part of the day (afternoon hours). Of note, the timing of the daily rhythm of body temperature did not vary seasonally, although the amplitude did change, leading to a seasonal alteration in the phase relationship between inactivity and the body temperature rhythm. Because during periods of inactivity the oryx were presumably asleep for much of the time, we speculate that the daytime shift in inactivity may allow the oryx to take advantage of the thermoregulatory physiology of sleep, which likely occurs when the animal is inactive for more than 1 h, to mitigate environmentally induced increases in body temperature. © 2016 The Author(s).

Does physiological acclimation to climate warming stabilize the ratio of canopy respiration to photosynthesis?

PubMed

Drake, John E; Tjoelker, Mark G; Aspinwall, Michael J; Reich, Peter B; Barton, Craig V M; Medlyn, Belinda E; Duursma, Remko A

2016-08-01

Given the contrasting short-term temperature dependences of gross primary production (GPP) and autotrophic respiration, the fraction of GPP respired by trees is predicted to increase with warming, providing a positive feedback to climate change. However, physiological acclimation may dampen or eliminate this response. We measured the fluxes of aboveground respiration (Ra ), GPP and their ratio (Ra /GPP) in large, field-grown Eucalyptus tereticornis trees exposed to ambient or warmed air temperatures (+3°C). We report continuous measurements of whole-canopy CO2 exchange, direct temperature response curves of leaf and canopy respiration, leaf and branch wood respiration, and diurnal photosynthetic measurements. Warming reduced photosynthesis, whereas physiological acclimation prevented a coincident increase in Ra . Ambient and warmed trees had a common nonlinear relationship between the fraction of GPP that was respired above ground (Ra /GPP) and the mean daily temperature. Thus, warming significantly increased Ra /GPP by moving plants to higher positions on the shared Ra /GPP vs daily temperature relationship, but this effect was modest and only notable during hot conditions. Despite the physiological acclimation of autotrophic respiration to warming, increases in temperature and the frequency of heat waves may modestly increase tree Ra /GPP, contributing to a positive feedback between climate warming and atmospheric CO2 accumulation. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Increasing spin crossover cooperativity in 2D Hofmann-type materials with guest molecule removal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zenere, Katrina A.; Duyker, Samuel G.; Trzop, Elzbieta

Ambient temperature spin crossover with wide hysteresis has been achieved in 2D Hofmann-type materials, where removal of guest molecules optimises ligand–ligand interactions, resulting in increased cooperativity.

Increasing spin crossover cooperativity in 2D Hofmann-type materials with guest molecule removal

DOE PAGES

Zenere, Katrina A.; Duyker, Samuel G.; Trzop, Elzbieta; ...

2018-01-01

Ambient temperature spin crossover with wide hysteresis has been achieved in 2D Hofmann-type materials, where removal of guest molecules optimises ligand–ligand interactions, resulting in increased cooperativity.

Adsorption of cadmium by sulphur dioxide treated activated carbon.

PubMed

Macías-García, A; Gómez-Serrano, V; Alexandre-Franco, M F; Valenzuela-Calahorro, C

2003-10-01

Merck carbon (1.5 mm) was treated in three ways: heating from ambient temperature to 900 degrees C in SO(2); treatment at ambient temperature in SO(2); or successive treatments in SO(2) and H(2)S at ambient temperature. All samples were then characterised and tested as adsorbents of Cd(2+) from aqueous solution. The characterisation was in terms of composition by effecting ultimate and proximate analyses and also of textural properties by N(2) adsorption at -196 degrees C. Kinetics and extent of the adsorption process of Cd(2+) were studied at 25 and 45 degrees C at pH of the Cd(2+) solution (i.e., 6.2) and at 25 degrees C also at pH 2.0. The various treatments of the starting carbon had no significant effect on the kinetics of the adsorption of Cd(2+), but increased its adsorption capacity. The most effective treatment was heating to 900 degrees C, the adsorption in this case being 70.3% more than that of the starting carbon. The adsorption increased at 45 degrees C but decreased at pH 2.0 when compared to adsorption at 25 degrees C and pH 6.2, respectively.

Thermal stability of Pt-Ti bilayer films annealing in vacuum and ambient atmosphere

NASA Astrophysics Data System (ADS)

Weng, Sizhe; Qiao, Li; Wang, Peng

2018-06-01

The thermal stability of platinum/titanium bilayer film dominates the performance when the film electrodes operate under extreme conditions, such as high temperature. In this study, a platinum/titanium bilayer film deposited by magnetron sputtering was used as a model system to study the influence of annealing in vacuum and ambient atmosphere on structural and electrical resistivity changes. The results show that in both cases blow 773 K annealing the metal platinum is the dominant phase, the alloying and the diffusion happen only at the interface of Pt and Ti. Two different structural evolutions set in when the temperature above 873 K, in vacuum an alloying process promotes with increasing of annealing temperature and metal Pt phase transforms to TiPt8 and finally to TiPt3 compounds, which leads to the increase of electrical resistivity. In ambient atmosphere annealing, when titanium diffused out to the surface of film, the oxidation reaction between titanium and oxygen suppresses the alloying process between platinum and titanium, in this case the metal Pt phase remains in the film and starts to agglomerate, defects such as grain boundary and voids in film reduced due to the recrystallization, results in the reduction of electrical resistivity.

Simulation of the real efficiencies of high-efficiency silicon solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sachenko, A. V., E-mail: sach@isp.kiev.ua; Skrebtii, A. I.; Korkishko, R. M.

The temperature dependences of the efficiency η of high-efficiency solar cells based on silicon are calculated. It is shown that the temperature coefficient of decreasing η with increasing temperature decreases as the surface recombination rate decreases. The photoconversion efficiency of high-efficiency silicon-based solar cells operating under natural (field) conditions is simulated. Their operating temperature is determined self-consistently by simultaneously solving the photocurrent, photovoltage, and energy-balance equations. Radiative and convective cooling mechanisms are taken into account. It is shown that the operating temperature of solar cells is higher than the ambient temperature even at very high convection coefficients (~300 W/m{sup 2}more » K). Accordingly, the photoconversion efficiency in this case is lower than when the temperature of the solar cells is equal to the ambient temperature. The calculated dependences for the open-circuit voltage and the photoconversion efficiency of high-quality silicon solar cells under concentrated illumination are discussed taking into account the actual temperature of the solar cells.« less

Effects of Cryogenic Temperature on Fracture Toughness of Core-Shell Rubber (CSR) Toughened Epoxy Nanocomposites

NASA Technical Reports Server (NTRS)

Wang, J.; Cannon, S. A.; Magee, D.; Schneider, J. A.

2008-01-01

This study investigated the effects of core-shell rubber (CSR) nanoparticles on the mechanical properties and fracture toughness of an epoxy resin at ambient and liquid nitrogen (LN2) temperatures. Varying amounts of Kane Ace MX130 toughening agent were added to a commercially available EPON 862/Epikure W epoxy resin. Elastic modulus was calculated using quasi-static tensile data. Fracture toughness was evaluated by the resulting breaking energy measured in Charpy impact tests conducted on an instrumented drop tower. The size and distribution of the CSR nanoparticles were characterized using Transmission Electron Microscopy (TEM) and Small Angle X-ray Scattering (SAXS). Scanning Electron Microscopy (SEM) was used to study the fracture surface morphology. The addition of the CSR nanoparticles increased the breaking energy with negligible change in elastic modulus and ultimate tensile stress (UTS). At ambient temperature the breaking energy increased with increasing additions of the CSR nanoparticles, while at LN2 temperatures, it reached a maximum at 5 wt% CSR concentration. KEY WORDS: liquid nitrogen (LN2) properties, fracture toughness, core-shell rubber (CSR).

Evaluation of environmental levels of aromatic hydrocarbons in gasoline service stations by gas chromatography.

PubMed

Periago, J F; Zambudio, A; Prado, C

1997-08-22

The volume of gasoline sold in refuelling operations and the ambient temperature, can increase significantly the environmental levels of aromatic hydrocarbon vapours and subsequently, the occupational risk of gasoline service station attendants, specially in the case of benzene. We have evaluated the occupational exposure to aromatic hydrocarbons by means of personal-breathing-zone samples of gasoline vapours in a service station attendant population. This evaluation was carried out using diffusive samplers, in two periods at quite different temperatures (March and July). A significant relationship between the volume of gasoline sold during the shift and the ambient concentration of benzene, toluene, and xylenes was found for each worker sampled. Furthermore a significant difference was found between the time-weighted average concentration of aromatic compounds measured in March, with ambient temperatures of 14-15 degrees C and July, with temperatures of 28-30 degrees C. In addition, 20% of the population sampled in the last period were exposed to a time-weighted average concentration of benzene above the proposed Threshold Limit Value of 960 micrograms/m(3) of the American Conference of Governmental Industrial Hygienists (ACGIH).

Food and agriculture in the 21st century: A cotton example

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, K.R.; Hodges, H.F.; McKinion, J.J.

1996-03-01

Cotton producers in the 21st century will be growing crops in different climates than today. Atmospheric CO{sub 2} concentration [CO{sub 2}] will likely exceed 700 {micro}l/l by the latter half of the next century, and the mean global temperature has been predicted to be 1.5 to 5.9 C higher than today. A 5 C increase will quadruple the number of days per year in which the mean temperature is above-optimum for cotton growth, and many days will be so hot that flowers will abscise in the US Cottonbelt. Further, the incidence of extreme weather events within a growing season hasmore » also been predicted to increase. Agricultural productivity is extremely sensitive to changes projected in the environment and if the projected changes occur, major changes in crop production will need to take place and both food and fiber will likely be very different from those of today. Doubling the atmospheric [CO{sub 2}] results in increased photosynthesis in C{sub 3} plants and dry matter accumulation. Season-long exposure to twice ambient [CO{sub 2}] (700 {micro}l/l) caused cotton plants growing in optimum temperature to produce 66% more dry matter than plants grown in ambient [CO{sub 2}]. Crops will respond to water and nitrogen deficits to about the same extent in a high-[CO{sub 2}] as to similar stresses in today`s ambient [CO{sub 2}] environment. The projected increases in temperature will cause more important and negative effects on crop production. 49 refs., 13 figs., 2 tabs.« less

Effect of heat stress on performance and expression of selected amino acid and glucose transporters, HSP90, leptin and ghrelin in growing pigs.

PubMed

Cervantes, Miguel; Cota, Margarita; Arce, Néstor; Castillo, Gilberto; Avelar, Ernesto; Espinoza, Salvador; Morales, Adriana

2016-07-01

Exposing animals to high ambient temperature provokes heat stress (HS) that may affect cellular function and reduced productive performance. The effect of chronic exposure (21d) of pigs to high ambient temperature on expression of amino acid (b(0,+)AT, CAT1) and glucose (SGLT1, GLUT4) transporters, ghrelin, leptin and HSP90 was evaluated. Eighteen pigs (32.6kg body weight) were distributed into 3 groups: (1) pigs housed under natural high ambient temperature conditions, and fed ad libitum (HS); (2) pigs housed in an air-conditioned room at 24°C (thermo-neutral) fed ad libitum (TNad); (3) pigs housed as in (2), but pair-fed with the HS pigs (TNpf). Body temperature, respiratory frequency, weight gain, feed intake, and feed conversion ratio were measured. At d-21 pigs were euthanized and samples from stomach, duodenum, jejunum, liver, longissimus and semitendinosus muscles, and white adipose tissue were collected for mRNA analysis. In the HS room ambient temperature fluctuated every day (23.6-37.6°C). Respiratory frequency and body temperature were higher in HS pigs (P<0.001). Weight gain and feed intake of TNad were higher (P<0.001) than TNpf and HS; gain: feed ratio was not affected by ambient temperature. Expression of HSP90 was higher in duodenum and longissimus (P≤0.038) of HS compared to TNpf. Expression of ghrelin, leptin and b(0,+)AT were not affected by ambient temperature (P>0.050). CAT1 expression in liver was higher (P=0.050) but in longissimus was lower (P=0.017) in HS than in TNpf pigs. Expression of SGLT1 was higher (P=0.045) in duodenum of HS than in TNpf but it was not different in jejunum (P=0.545); GLUT4 tended to be higher in liver and semitendinosus of HS pigs (P=0.063). In conclusion, feed intake remains low whereas respiratory frequency and body temperature remain higher; and expression of HSP90, CAT1, SGLT1 and GLUT4 increases in some tissues in pigs under chronic HS conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

High Ambient Temperatures and Risk of Motor Vehicle Crashes in Catalonia, Spain (2000–2011): A Time-Series Analysis

PubMed Central

Escalera-Antezana, Juan Pablo; Dadvand, Payam; Llatje, Òscar; Barrera-Gómez, Jose; Cunillera, Jordi; Medina-Ramón, Mercedes; Pérez, Katherine

2015-01-01

Background Experimental studies have shown a decrease in driving performance at high temperatures. The epidemiological evidence for the relationship between heat and motor vehicle crashes is not consistent. Objectives We estimated the impact of high ambient temperatures on the daily number of motor vehicle crashes and, in particular, on crashes involving driver performance factors (namely distractions, driver error, fatigue, or sleepiness). Methods We performed a time-series analysis linking daily counts of motor vehicle crashes and daily temperature or occurrence of heat waves while controlling for temporal trends. All motor vehicle crashes with victims that occurred during the warm period of the years 2000–2011 in Catalonia (Spain) were included. Temperature data were obtained from 66 weather stations covering the region. Poisson regression models adjusted for precipitation, day of the week, month, year, and holiday periods were fitted to quantify the associations. Results The study included 118,489 motor vehicle crashes (an average of 64.1 per day). The estimated risk of crashes significantly increased by 2.9% [95% confidence interval (CI): 0.7%, 5.1%] during heat wave days, and this association was stronger (7.7%, 95% CI: 1.2%, 14.6%) when restricted to crashes with driver performance–associated factors. The estimated risk of crashes with driver performance factors significantly increased by 1.1% (95% CI: 0.1%, 2.1%) for each 1°C increase in maximum temperature. Conclusions Motor vehicle crashes involving driver performance–associated factors were increased in association with heat waves and increasing temperature. These findings are relevant for designing preventive plans in a context of global warming. Citation Basagaña X, Escalera-Antezana JP, Dadvand P, Llatje Ò, Barrera-Gómez J, Cunillera J, Medina-Ramón M, Pérez K. 2015. High ambient temperatures and risk of motor vehicle crashes in Catalonia, Spain (2000–2011): a time-series analysis. Environ Health Perspect 123:1309–1316; http://dx.doi.org/10.1289/ehp.1409223 PMID:26046727

Hydrostatic temperature calculations. [in synoptic meteorology

NASA Technical Reports Server (NTRS)

Raymond, William H.

1987-01-01

Comparisons are made between hydrostatically computed temperatures and ambient temperatures associated with nine different data sources, including analyses, forecasts and conventional observations. Five-day averages and the day-to-day variations in the root-mean-square temperature differences are presented. Several different numerical and interpolation procedures are examined. Error correction and a constrained optimum procedure that minimizes ambient minus calculated hydrostatic temperature differences are introduced. Systematic differences between ambient and hydrostatic temperatures are found to be associated with the sinoptic situation. When compared with ambient temperatures, hydrostatic temperatures at 500 mb tend to be too warm at or in front of a trough and too cold behind the trough. In the vertical direction, for the eight-level configuration tested, the average hydrostatic temperatures are too cold at low levels (850, 700 mb) and too warm at upper levels, (300, 250 mb).

Temperature-mediated growth thresholds of Acrobasis vaccinii (Lepidoptera: Pyralidae)

USDA-ARS?s Scientific Manuscript database

Degree-day models link ambient temperature to the development of insects, making such models valuable tools in integrated pest management. Phenology models increase management efficacy by quantifying and predicting pest phenology. In Wisconsin, the top pest of cranberry production is the cranberry f...

Simulation of water removal process and optimization of aeration strategy in sewage sludge composting.

PubMed

Zhou, Hai-Bin; Chen, Tong-Bin; Gao, Ding; Zheng, Guo-Di; Chen, Jun; Pan, Tian-Hao; Liu, Hong-Tao; Gu, Run-Yao

2014-11-01

Reducing moisture in sewage sludge is one of the main goals of sewage sludge composting and biodrying. A mathematical model was used to simulate the performance of water removal under different aeration strategies. Additionally, the correlations between temperature, moisture content (MC), volatile solids (VS), oxygen content (OC), and ambient air temperature and aeration strategies were predicted. The mathematical model was verified based on coefficients of correlation between the measured and predicted results of over 0.80 for OC, MC, and VS, and 0.72 for temperature. The results of the simulation showed that water reduction was enhanced when the average aeration rate (AR) increased to 15.37 m(3) min(-1) (6/34 min/min, AR: 102.46 m(3) min(-1)), above which no further increase was observed. Furthermore, more water was removed under a higher on/off time of 7/33 (min/min, AR: 87.34 m(3) min(-1)), and when ambient air temperature was higher. Copyright © 2014 Elsevier Ltd. All rights reserved.

The carotid rete and artiodactyl success.

PubMed

Mitchell, G; Lust, A

2008-08-23

Since the Eocene, the diversity of artiodactyls has increased while that of perissodactyls has decreased. Reasons given for this contrasting pattern are that the evolution of a ruminant digestive tract and improved locomotion in artiodactyls were adaptively advantageous in the highly seasonal post-Eocene climate. We suggest that evolution of a carotid rete, a structure highly developed in artiodactyls but absent in perissodactyls, was at least as important. The rete confers an ability to regulate brain temperature independently of body temperature. The net effect is that in hot ambient conditions artiodactyls are able to conserve energy and water, and in cold ambient conditions they are able to conserve body temperature. In perissodactyls, brain and body temperature change in parallel and thermoregulation requires abundant food and water to warm/cool the body. Consequently, perissodactyls occupy habitats of low seasonality and rich in food and water, such as tropical forests. Conversely, the increased thermoregulatory flexibility of artiodactyls has facilitated invasion of new adaptive zones ranging from the Arctic Circle to deserts and tropical savannahs.

AVGAS/AUTOGAS (Aviation Gasoline/Automobile Gasoline) Comparison. Winter Grade Fuels.

DTIC Science & Technology

1986-07-01

mass MAP Manifold pressure - inHg MON Motor Octane Number NIPER National Institute of Petroleum and Energy Resources Pamb Ambient pressure - inHg...pressure - psig si Sea level (used as a subscript) STC Supplemental Type Certificate Tamb Ambient temperature - degC or degF Tdew Dew point - degC or degF...temperature deg C #2 exhaust gas temperature deg C #3 exhaust gas temperature deg C #4 exhaust gas temperature deg C Ambient air temperature deg C 6

Complex and interactive effects of ocean acidification and temperature on epilithic and endolithic coral-reef turf algal assemblages

NASA Astrophysics Data System (ADS)

Johnson, Maggie D.; Comeau, Steeve; Lantz, Coulson A.; Smith, Jennifer E.

2017-12-01

Turf algal assemblages are ubiquitous primary producers on coral reefs, but little is known about the response of this diverse group to ocean acidification (OA) across different temperatures. We tested the hypothesis that CO2 influences the functional response of epilithic and endolithic turf assemblages to increasing temperature. Replicate carbonate plugs covered by turf were collected from the reef and exposed to ambient and high pCO2 (1000 µatm) conditions for 3 weeks. Each pCO2 treatment was replicated across six temperatures (24.0-31.5 °C) that spanned the full seasonal temperature range on a fringing reef in Moorea, French Polynesia, and included one warming treatment (3 °C above daily average temperatures). Temperature and CO2 enrichment had complex, and sometimes interactive, effects on turf metabolism and growth. Photosynthetic and respiration rates were enhanced by increasing temperature, with an interactive effect of CO2 enrichment. Photosynthetic rates were amplified by high CO2 in the warmest temperatures, while the increase in respiration rates with temperature were enhanced under ambient CO2. Epilithic turf growth rates were not affected by temperature, but increased in response to CO2 enrichment. We found that CO2 and temperature interactively affected the endolithic assemblage, with the highest growth rates under CO2 enrichment, but only at the warmest temperatures. These results demonstrate how OA may influence algal physiology and growth across a range of ecologically relevant temperatures, and indicate that the effects of CO2 enrichment on coral-reef turf assemblages can be temperature dependent. The complex effects of CO2 enrichment and temperature across a suite of algal responses illustrates the importance of incorporating multiple stressors into global change experiments.

Comprehensive particle characterization of modern gasoline and diesel passenger cars at low ambient temperatures

NASA Astrophysics Data System (ADS)

Mathis, Urs; Mohr, Martin; Forss, Anna-Maria

Particle measurements were performed in the exhaust of five light-duty vehicles (Euro-3) at +23, -7, and -20 °C ambient temperatures. The characterization included measurements of particle number, active surface area, number size distribution, and mass size distribution. We investigated two port-injection spark-ignition (PISI) vehicles, a direct-injection spark-ignition (DISI) vehicle, a compressed ignition (CI) vehicle with diesel particle filter (DPF), and a CI vehicle without DPF. To minimize sampling effects, particles were directly sampled from the tailpipe with a novel porous tube diluter at controlled sampling parameters. The diluted exhaust was split into two branches to measure either all or only non-volatile particles. Effect of ambient temperature was investigated on particle emission for cold and warmed-up engine. For the gasoline vehicles and the CI vehicle with DPF, the main portion of particle emission was found in the first minutes of the driving cycle at cold engine start. The particle emission of the CI vehicle without DPF was hardly affected by cold engine start. For the PISI vehicles, particle number emissions were superproportionally increased in the diameter size range from 0.1 to 0.3 μm during cold start at low ambient temperature. Based on the particle mass size distribution, the DPF removed smaller particles ( dp<0.5μm) more efficiently than larger particles ( dp>0.5μm). No significant effect of ambient temperature was observed when the engine was warmed up. Peak emission of volatile nanoparticles only took place at specific conditions and was poorly repeatable. Nucleation of particles was predominately observed during or after strong acceleration at high speed and during regeneration of the DPF.

High DNA stability in white blood cells and buffy coat lysates stored at ambient temperature under anoxic and anhydrous atmosphere

PubMed Central

Luis, Aurélie; Colotte, Marthe; Tuffet, Sophie; Bonnet, Jacques

2017-01-01

Conventional storage of blood-derived fractions relies on cold. However, lately, ambient temperature preservation has been evaluated by several independent institutions that see economic and logistic advantages in getting rid of the cold chain. Here we validated a novel procedure for ambient temperature preservation of DNA in white blood cell and buffy coat lysates based on the confinement of the desiccated biospecimens under anoxic and anhydrous atmosphere in original hermetic minicapsules. For this validation we stored encapsulated samples either at ambient temperature or at several elevated temperatures to accelerate aging. We found that DNA extracted from stored samples was of good quality with a yield of extraction as expected. Degradation rates were estimated from the average fragment size of denatured DNA run on agarose gels and from qPCR reactions. At ambient temperature, these rates were too low to be measured but the degradation rate dependence on temperature followed Arrhenius’ law, making it possible to extrapolate degradation rates at 25°C. According to these values, the DNA stored in the encapsulated blood products would remain larger than 20 kb after one century at ambient temperature. At last, qPCR experiments demonstrated the compatibility of extracted DNA with routine DNA downstream analyses. Altogether, these results showed that this novel storage method provides an adequate environment for ambient temperature long term storage of high molecular weight DNA in dehydrated lysates of white blood cells and buffy coats. PMID:29190767

High DNA stability in white blood cells and buffy coat lysates stored at ambient temperature under anoxic and anhydrous atmosphere.

PubMed

Fabre, Anne-Lise; Luis, Aurélie; Colotte, Marthe; Tuffet, Sophie; Bonnet, Jacques

2017-01-01

Conventional storage of blood-derived fractions relies on cold. However, lately, ambient temperature preservation has been evaluated by several independent institutions that see economic and logistic advantages in getting rid of the cold chain. Here we validated a novel procedure for ambient temperature preservation of DNA in white blood cell and buffy coat lysates based on the confinement of the desiccated biospecimens under anoxic and anhydrous atmosphere in original hermetic minicapsules. For this validation we stored encapsulated samples either at ambient temperature or at several elevated temperatures to accelerate aging. We found that DNA extracted from stored samples was of good quality with a yield of extraction as expected. Degradation rates were estimated from the average fragment size of denatured DNA run on agarose gels and from qPCR reactions. At ambient temperature, these rates were too low to be measured but the degradation rate dependence on temperature followed Arrhenius' law, making it possible to extrapolate degradation rates at 25°C. According to these values, the DNA stored in the encapsulated blood products would remain larger than 20 kb after one century at ambient temperature. At last, qPCR experiments demonstrated the compatibility of extracted DNA with routine DNA downstream analyses. Altogether, these results showed that this novel storage method provides an adequate environment for ambient temperature long term storage of high molecular weight DNA in dehydrated lysates of white blood cells and buffy coats.

Data book for 12.5-inch diameter SRB thermal model water flotation test - 14.7 psia, series P024

NASA Technical Reports Server (NTRS)

Allums, S. L.

1974-01-01

Tests were conducted to determine how thermal conditions affect space shuttle solid rocket booster (SRB) flotation. Acceleration, pressure, and temperature data were recorded from initial water impact to final flotation position using a 12.5-inch diameter thermal model of the SRB at ambient pressure. The model was 136.9 inches long and weighed 117.3 lbm. The tests indicated the following differences from ambient temperature tests: (1) significant negative static pressures can occur during penetration; (2) maximum penetration is increased; and (3) final flotation is in the spar buoy mode.

Investigation of Transmission Warming Technologies at Various Ambient Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jehlik, Forrest; Iliev, Simeon; Wood, Eric

This work details two approaches for evaluating transmission warming technology: experimental dynamometer testing and development of a simplified transmission efficiency model to quantify effects under varied real world ambient and driving conditions. Two vehicles were used for this investigation: a 2013 Ford Taurus and a 2011 Ford Fusion. The Taurus included a production transmission warming system and was tested over hot and cold ambient temperatures with the transmission warming system enabled and disabled. A robot driver was used to minimize driver variability and increase repeatability. Additionally the Fusion was tested cold and with the transmission pre-heated prior to completing themore » test cycles. These data were used to develop a simplified thermally responsive transmission model to estimate effects of transmission warming in real world conditions. For the Taurus, the fuel consumption variability within one standard deviation was shown to be under 0.5% for eight repeat Urban Dynamometer Driving Cycles (UDDS). These results were valid with the transmission warming system active or passive. Using the transmission warming system under 22 degrees C ambient temperature, fuel consumption reduction was shown to be 1.4%. For the Fusion, pre-warming the transmission reduced fuel consumption 2.5% for an urban drive cycle at -7 degrees C ambient temperature, with 1.5% of the 2.5% gain associated with the transmission, while consumption for the US06 test was shown to be reduced by 7% with 5.5% of the 7% gain associated with the transmission. It was found that engine warming due to conduction between the pre-heated transmission and the engine resulted in the remainder of the benefit. For +22 degrees C ambient tests, the pre-heated transmission was shown to reduce fuel consumption approximately 1% on an urban cycle, while no benefit was seen for the US06 cycle. The simplified modeling results showed gains in efficiency ranging from 0-1.5% depending on the ambient temperature and drive cycle.« less

Which are the most important parameters for modelling carbon assimilation in boreal Norway spruce under elevated [CO(2)] and temperature conditions?

PubMed

Hall, Marianne; Medlyn, Belinda E; Abramowitz, Gab; Franklin, Oskar; Räntfors, Mats; Linder, Sune; Wallin, Göran

2013-11-01

Photosynthesis is highly responsive to environmental and physiological variables, including phenology, foliage nitrogen (N) content, atmospheric CO2 concentration ([CO2]), irradiation (Q), air temperature (T) and vapour pressure deficit (D). Each of these responses is likely to be modified by long-term changes in climatic conditions such as rising air temperature and [CO2]. When modelling photosynthesis under climatic changes, which parameters are then most important to calibrate for future conditions? To assess this, we used measurements of shoot carbon assimilation rates and microclimate conditions collected at Flakaliden, northern Sweden. Twelve 40-year-old Norway spruce trees were enclosed in whole-tree chambers and exposed to elevated [CO2] and elevated air temperature, separately and in combination. The treatments imposed were elevated temperature, +2.8 °C in July/August and +5.6 °C in December above ambient, and [CO2] (ambient CO2 ∼370 μ mol mol(-1), elevated CO2 ∼700 μ mol mol(-1)). The relative importance of parameterization of Q, T and D responses for effects on the photosynthetic rate, expressed on a projected needle area, and the annual shoot carbon uptake was quantified using an empirical shoot photosynthesis model, which was developed and fitted to the measurements. The functional form of the response curves was established using an artificial neural network. The [CO2] treatment increased annual shoot carbon (C) uptake by 50%. Most important was effects on the light response curve, with a 67% increase in light-saturated photosynthetic rate, and a 52% increase in the initial slope of the light response curve. An interactive effect of light saturated photosynthetic rate was found with foliage N status, but no interactive effect for high temperature and high CO2. The air temperature treatment increased the annual shoot C uptake by 44%. The most important parameter was the seasonality, with an elongation of the growing season by almost 4 weeks. The temperature response curve was almost flat over much of the temperature range. A shift in temperature optimum had thus an insignificant effect on modelled annual shoot C uptake. The combined temperature and [CO2] treatment resulted in a 74% increase in annual shoot C uptake compared with ambient conditions, with no clear interactive effects on parameter values.

Incubation temperature alters thermal preference and response to heat stress of broiler chickens along the rearing phase.

PubMed

Morita, V S; Almeida, V R; Matos Junior, J B; Vicentini, T I; van den Brand, H; Boleli, I C

2016-08-01

The current study aimed to investigate whether embryonic temperature manipulation may alter thermal preference throughout the rearing phase of broiler chickens and how this manipulation may affect response to thermal challenge, metabolism, growth rate and feed intake rate. Eggs were exposed to a constant incubation temperature [machine temperatures: 36°C (Low), 37.5°C (Control), and 39°C (High); eggshell temperature of 37.4 ± 0.08°C, 37.8 ± 0.15°C, and 38.8 ± 0.33°C, respectively] from d 13 till hatching. Low treatment chickens showed lower plasma T3 and GH levels at d 1 of age and lower T3 level at d 42 of age compared to the Control treatment. Preferred ambient, rectal temperature, T4 level, growth rate, food intake rate, and response to thermal challenge were not altered in these chickens. On the other hand, High-treatment chickens exhibited high preferred ambient temperature and rectal temperature during the first 2 wk post-hatch, lower plasma T3 level at d 21 and 42 and a delayed increase in respiratory movement in response to thermal challenge compared to the Control treatment. However, chickens subjected to the Control and High treatments did not differ in T4 and GH level and performance. We conclude that exposure to high temperature during late embryonic development has long-lasting effects on the thermoregulatory system of broiler chickens by affecting the heat tolerance of these chickens. Moreover, the preferred ambient temperature of the chickens from heat-treated eggs correspond to those recommended for the strain under study, whereas for the cold-treated and control-chickens it was 1°C below, indicating that incubation temperature might have consequences on the ambient temperature chickens require during the rearing phase. © 2016 Poultry Science Association Inc.

Comparative study of the oxidation of NiAl(100) by molecular oxygen and water vapor using ambient-pressure X-ray photoelectron spectroscopy

DOE PAGES

Liu, Qianqian; Qin, Hailang; Boscoboinik, Jorge Anibal; ...

2016-10-11

The oxidation behavior of NiAl(100) by molecular oxygen and water vapor under a near-ambient pressure of 0.2 Torr is monitored using ambient-pressure X-ray photoelectron spectroscopy. O 2 exposure leads to the selective oxidation of Al at temperatures ranging from 40 to 500 °C. By contrast, H 2O exposure results in the selective oxidation of Al at 40 and 200 °C, and increasing the oxidation temperature above 300 °C leads to simultaneous formation of both Al and Ni oxides. Furthermore, these results demonstrate that the O 2 oxidation forms a nearly stoichiometric Al 2O 3 structure that provides improved protection tomore » the metallic substrate by barring the outward diffusion of metals. By contrast, the H 2O oxidation results in the formation of a defective oxide layer that allows outward diffusion of Ni at elevated temperatures for simultaneous NiO formation.« less

Comparative study of the oxidation of NiAl(100) by molecular oxygen and water vapor using ambient-pressure X-ray photoelectron spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Qianqian; Qin, Hailang; Boscoboinik, Jorge Anibal

The oxidation behavior of NiAl(100) by molecular oxygen and water vapor under a near-ambient pressure of 0.2 Torr is monitored using ambient-pressure X-ray photoelectron spectroscopy. O 2 exposure leads to the selective oxidation of Al at temperatures ranging from 40 to 500 °C. By contrast, H 2O exposure results in the selective oxidation of Al at 40 and 200 °C, and increasing the oxidation temperature above 300 °C leads to simultaneous formation of both Al and Ni oxides. Furthermore, these results demonstrate that the O 2 oxidation forms a nearly stoichiometric Al 2O 3 structure that provides improved protection tomore » the metallic substrate by barring the outward diffusion of metals. By contrast, the H 2O oxidation results in the formation of a defective oxide layer that allows outward diffusion of Ni at elevated temperatures for simultaneous NiO formation.« less

Abiotic stress of ambient cold temperature regulates the host receptivity to pathogens by cell surfaced sialic acids.

PubMed

Moon, Seong-Cheol; Joo, Su-Yeon; Chung, Tae-Wook; Choi, Hee-Jung; Park, Mi-Ju; Choi, Hee-Jin; Bae, Sung-Jin; Kim, Keuk-Jun; Kim, Cheorl-Ho; Joo, Myungsoo; Ha, Ki-Tae

2016-07-29

Ambient cold temperature, as an abiotic stress, regulates the survival, stability, transmission, and infection of pathogens. However, the effect of cold temperature on the host receptivity to the pathogens has not been fully studied. In this study, the expression of terminal α-2,3- and α-2,6-sialic acids were increased in murine lung tissues, especially bronchial epithelium, by exposure to cold condition. The expression of several sialyltransferases were also increased by exposure to cold temperature. Furthermore, in human bronchial epithelial BEAS-2B cells, the expressions of α-2,3- and α-2,6-sialic acids, and mRNA levels of sialyltransferases were increased in the low temperature condition at 33 °C. On the other hand, the treatment of Lith-Gly, a sialyltransferase inhibitor, blocked the cold-induced expression of sialic acids on surface of BEAS-2B cells. The binding of influenza H1N1 hemagglutinin (HA) toward BEAS-2B cells cultured at low temperature condition was increased, compared to 37 °C. In contrast, the cold-increased HA binding was blocked by treatment of lithocholicglycine and sialyl-N-acetyl-D-lactosamines harboring α-2,3- and α-2,6-sialyl motive. These results suggest that the host receptivity to virus at cold temperature results from the expressions of α-2,3- and α-2,6-sialic acids through the regulation of sialyltransferase expression. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of change in ambient temperature on core temperature during the daytime.

PubMed

Kakitsuba, Naoshi; White, Matthew D

2014-07-01

In this study, the hypothesis is tested that continuous increases in ambient temperature (Ta) during daytime would give elevated core and skin temperatures, and consequently better thermal sensation and comfort. Rectal temperature (Tre), skin temperatures and regional dry heat losses at 7 sites were continuously measured for 10 Japanese male subjects in three thermal conditions: cond. 1, stepwise increases in Ta from 26 °C at 9 h00 to 30 °C at 18 h00; cond. 2, steady Ta at 28 °C from 9 h00 to 18 h00 and cond. 3, stepwise decreases in Ta from 30 °C at 9 h00 to 26 °C at 18 h00. Oxygen consumption was measured and thermal sensation and comfort votes were monitored at 15 min intervals. Body weight loss was measured at 1 h intervals. While Tre increased continuously in the morning period in any condition, it increased to a significantly greater (p<0.05) 36.9±0.3 °C at 18 h00 in cond. 1 relative to 36.7±0.28 °C in Cond. 2 and 36.5±0.37 °C in cond. 3. Better thermal comfort was observed in the afternoon and the evening in Cond.1 as compared with the other 2 conditions. Thus, a progressive and appropriate increase in Ta may induce optimal cycle in core temperature during daytime, particularly for a resting person.

The Genetic Control of Reproductive Development under High Ambient Temperature.

PubMed

Ejaz, Mahwish; von Korff, Maria

2017-01-01

Ambient temperature has a large impact on reproductive development and grain yield in temperate cereals. However, little is known about the genetic control of development under different ambient temperatures. Here, we demonstrate that in barley (Hordeum vulgare), high ambient temperatures accelerate or delay reproductive development depending on the photoperiod response gene PHOTOPERIOD1 (Ppd-H1) and its upstream regulator EARLY FLOWERING3 (HvELF3). A natural mutation in Ppd-H1 prevalent in spring barley delayed floral development and reduced the number of florets and seeds per spike, while the wild-type Ppd-H1 or a mutant Hvelf3 allele accelerated floral development and maintained the seed number under high ambient temperatures. High ambient temperature delayed the expression phase and reduced the amplitude of clock genes and repressed the floral integrator gene FLOWERING LOCUS T1 independently of the genotype. Ppd-H1-dependent variation in flowering time under different ambient temperatures correlated with relative expression levels of the BARLEY MADS-box genes VERNALIZATION1 (HvVRN1), HvBM3, and HvBM8 in the leaf. Finally, we show that Ppd-H1 interacts with regulatory variation at HvVRN1. Ppd-H1 only accelerated floral development in the background of a spring HvVRN1 allele with a deletion in the regulatory intron. The full-length winter Hvvrn1 allele was strongly down-regulated, and flowering was delayed by high temperatures irrespective of Ppd-H1 Our findings demonstrate that the photoperiodic and vernalization pathways interact to control flowering time and floret fertility in response to ambient temperature in barley. © 2017 American Society of Plant Biologists. All Rights Reserved.

The Genetic Control of Reproductive Development under High Ambient Temperature1[OPEN

PubMed Central

2017-01-01

Ambient temperature has a large impact on reproductive development and grain yield in temperate cereals. However, little is known about the genetic control of development under different ambient temperatures. Here, we demonstrate that in barley (Hordeum vulgare), high ambient temperatures accelerate or delay reproductive development depending on the photoperiod response gene PHOTOPERIOD1 (Ppd-H1) and its upstream regulator EARLY FLOWERING3 (HvELF3). A natural mutation in Ppd-H1 prevalent in spring barley delayed floral development and reduced the number of florets and seeds per spike, while the wild-type Ppd-H1 or a mutant Hvelf3 allele accelerated floral development and maintained the seed number under high ambient temperatures. High ambient temperature delayed the expression phase and reduced the amplitude of clock genes and repressed the floral integrator gene FLOWERING LOCUS T1 independently of the genotype. Ppd-H1-dependent variation in flowering time under different ambient temperatures correlated with relative expression levels of the BARLEY MADS-box genes VERNALIZATION1 (HvVRN1), HvBM3, and HvBM8 in the leaf. Finally, we show that Ppd-H1 interacts with regulatory variation at HvVRN1. Ppd-H1 only accelerated floral development in the background of a spring HvVRN1 allele with a deletion in the regulatory intron. The full-length winter Hvvrn1 allele was strongly down-regulated, and flowering was delayed by high temperatures irrespective of Ppd-H1. Our findings demonstrate that the photoperiodic and vernalization pathways interact to control flowering time and floret fertility in response to ambient temperature in barley. PMID:28049855

The effects of ambient temperature on cerebrovascular mortality: an epidemiologic study in four climatic zones in China

PubMed Central

2014-01-01

Background Little evidence is available about the association between temperature and cerebrovascular mortality in China. This study aims to examine the effects of ambient temperature on cerebrovascular mortality in different climatic zones in China. Method We obtained daily data on weather conditions, air pollution and cerebrovascular deaths from five cities (Beijing, Tianjin, Shanghai, Wuhan, and Guangzhou) in China during 2004-2008. We examined city-specific associations between ambient temperature and the cerebrovascular mortality, while adjusting for season, long-term trends, day of the week, relative humidity and air pollution. We examined cold effects using a 1°C decrease in temperature below a city-specific threshold, and hot effects using a 1°C increase in temperature above a city-specific threshold. We used a meta-analysis to summarize the cold and hot effects across the five cities. Results Beijing and Tianjin (with low mean temperature) had lower thresholds than Shanghai, Wuhan and Guangzhou (with high mean temperature). In Beijing, Tianjin, Wuhan and Guangzhou cold effects were delayed, while in Shanghai there was no or short induction. Hot effects were acute in all five cities. The cold effects lasted longer than hot effects. The hot effects were followed by mortality displacement. The pooled relative risk associated with a 1°C decrease in temperature below thresholds (cold effect) was 1.037 (95% confidence interval (CI): 1.020, 1.053). The pooled relative risk associated with a 1°C increase in temperature above thresholds (hot effect) was 1.014 (95% CI: 0.979, 1.050). Conclusion Cold temperatures are significantly associated with cerebrovascular mortality in China, while hot effect is not significant. People in colder climate cities were sensitive to hot temperatures, while people in warmer climate cities were vulnerable to cold temperature. PMID:24690204

Microbial response of an acid forest soil to experimental soil warming

Treesearch

S.S. Arnold; I.J. Fernandez; L.E. Rustad; L.M. Zibilske

1999-01-01

Effects of increased soil temperature on soil microbial biomass and dehydrogenase activity were examined on organic (O) horizon material in a low-elevation spruce-fir ecosystem. Soil temperature was maintained at 5 °C above ambient during the growing season in the experimental plots, and soil temperature, moisture, microbial biomass, and dehydrogenase activity were...

Effects of Cooling During Exercise on Thermoregulatory Responses of Men With Paraplegia.

PubMed

Bongers, Coen C W G; Eijsvogels, Thijs M H; van Nes, Ilse J W; Hopman, Maria T E; Thijssen, Dick H J

2016-05-01

People with spinal cord injury (SCI) have an altered afferent input to the thermoregulatory center, resulting in a reduced efferent response (vasomotor control and sweating capacity) below the level of the lesion. Consequently, core body temperature rises more rapidly during exercise in individuals with SCI compared with people who are able-bodied. Cooling strategies may reduce the thermophysiological strain in SCI. The aim of this study was to examine the effects of a cooling vest on the core body temperature response of people with a thoracic SCI during submaximal exercise. Ten men (mean age=44 years, SD=11) with a thoracic lesion (T4-T5 or below) participated in this randomized crossover study. Participants performed two 45-minute exercise bouts at 50% maximal workload (ambient temperature 25°C), with participants randomized to a group wearing a cooling vest or a group wearing no vest (separate days). Core body temperature and skin temperature were continuously measured, and thermal sensation was assessed every 3 minutes. Exercise resulted in an increased core body temperature, skin temperature, and thermal sensation, whereas cooling did not affect core body temperature. The cooling vest effectively decreased skin temperature, increased the core-to-trunk skin temperature gradient, and tended to lower thermal sensation compared with the control condition. The lack of differences in core body temperature among conditions may be a result of the relative moderate ambient temperature in which the exercise was performed. Despite effectively lowering skin temperature and increasing the core-to-trunk skin temperature gradient, there was no impact of the cooling vest on the exercise-induced increase in core body temperature in men with low thoracic SCI. © 2016 American Physical Therapy Association.

The stress corrosion resistance and the cryogenic temperature mechanical properties of hot rolled Nitronic 32 bar material

NASA Technical Reports Server (NTRS)

Montano, J. W. L.

1977-01-01

The ambient and cryogenic temperature mechanical properties and the ambient temperature stress corrosion properties of hot rolled and centerless ground Nitronic 32 stainless steel bar material are presented. The mechanical properties of longitudinal specimens were evaluated at test temperatures from ambient to liquid hydrogen. The tensile test data indicated increasing smooth tensile strength with decreasing temperature to liquid hydrogen temperature. However, below -200 F (-129.0 C) the notched tensile strength decreased slightly and below -320 F (-196.0 C) the decrease was significant. The elongation and reduction of area decreased drastically at temperatures below -200 F (-129.0 C). The Charpy V-notched impact energy decreased steadily with decreasing test temperature. Stress corrosion tests were performed on longitudinal tensile specimens stressed to 0, 75, and 90 percent of the 0.2 percent yield strength and on transverse 'C'-ring specimens stressed to 75 and 90 percent of the yield strength and exposed to: alternate immersion in a 3.5 percent NaCl bath, humidity cabinet environment, and a 5 percent salt spray atmosphere. The longitudinal tensile specimens experienced no corrosive attack; however, the 'C'-rings exposed to the alternate immersion and to the salt spray experienced some shallow etching and pitting, respectively. Small cracks appeared in two of the 'C'-rings after one month exposure to the salt spray.

Does habitat fragmentation affect temperature-related life-history traits? A laboratory test with a woodland butterfly

PubMed Central

Karlsson, Bengt; Van Dyck, Hans

2005-01-01

Habitat fragmentation may change local climatic conditions leading to altered selection regimes for life-history traits in small ectotherms, including several insects. We investigated temperature-related performance in terms of fitness among populations of the woodland butterfly Pararge aegeria (L.) originating from populations of a closed, continuous woodland landscape versus populations of an open, highly fragmented agricultural landscape in central Belgium. Female fecundity and longevity were evaluated in a temperature-gradient experiment. As predicted, females of woodland landscape origin reached higher maximum daily fecundity and lifetime number of eggs than did agricultural landscape females at low ambient temperatures, but this reversed at high ambient temperature. Egg weight decreased with temperature, and eggs of woodland butterflies were smaller. Contrary to what is generally assumed, remaining thorax mass was a better predictor of lifetime reproductive output than was abdomen mass. Since we used the F2 generation from wild-caught females reared under common garden conditions, the observed effects are likely to rely on intrinsic, heritable variation. Our results suggest that differential selection regimes associated with different landscapes intervene by intraspecific variation in the response of a butterfly to variation in ambient temperature, and may thus be helpful when making predictions of future impacts on how wild populations respond to environmental conditions under a global change scenario, with increasing temperatures and fragmented landscapes. PMID:16024390

Elevated [CO2] does not ameliorate the negative effects of elevated temperature on drought-induced mortality in Eucalyptus radiata seedlings.

PubMed

Duan, Honglang; Duursma, Remko A; Huang, Guomin; Smith, Renee A; Choat, Brendan; O'Grady, Anthony P; Tissue, David T

2014-07-01

It has been reported that elevated temperature accelerates the time-to-mortality in plants exposed to prolonged drought, while elevated [CO(2)] acts as a mitigating factor because it can reduce stomatal conductance and thereby reduce water loss. We examined the interactive effects of elevated [CO(2)] and temperature on the inter-dependent carbon and hydraulic characteristics associated with drought-induced mortality in Eucalyptus radiata seedlings grown in two [CO(2)] (400 and 640 μL L(-1)) and two temperature (ambient and ambient +4 °C) treatments. Seedlings were exposed to two controlled drying and rewatering cycles, and then water was withheld until plants died. The extent of xylem cavitation was assessed as loss of stem hydraulic conductivity. Elevated temperature triggered more rapid mortality than ambient temperature through hydraulic failure, and was associated with larger water use, increased drought sensitivities of gas exchange traits and earlier occurrence of xylem cavitation. Elevated [CO(2)] had a negligible effect on seedling response to drought, and did not ameliorate the negative effects of elevated temperature on drought. Our findings suggest that elevated temperature and consequent higher vapour pressure deficit, but not elevated [CO(2)], may be the primary contributors to drought-induced seedling mortality under future climates. © 2013 John Wiley & Sons Ltd.

Pasture size effects on the ability of off-stream water or restricted stream access to alter the spatial/temporal distribution of grazing beef cows.

PubMed

Bisinger, J J; Russell, J R; Morrical, D G; Isenhart, T M

2014-08-01

For 2 grazing seasons, effects of pasture size, stream access, and off-stream water on cow distribution relative to a stream were evaluated in six 12.1-ha cool-season grass pastures. Two pasture sizes (small [4.0 ha] and large [12.1 ha]) with 3 management treatments (unrestricted stream access without off-stream water [U], unrestricted stream access with off-stream water [UW], and stream access restricted to a stabilized stream crossing [R]) were alternated between pasture sizes every 2 wk for 5 consecutive 4-wk intervals in each grazing season. Small and large pastures were stocked with 5 and 15 August-calving cows from mid May through mid October. At 10-min intervals, cow location was determined with Global Positioning System collars fitted on 2 to 3 cows in each pasture and identified when observed in the stream (0-10 m from the stream) or riparian (0-33 m from the stream) zones and ambient temperature was recorded with on-site weather stations. Over all intervals, cows were observed more (P ≤ 0.01) frequently in the stream and riparian zones of small than large pastures regardless of management treatment. Cows in R pastures had 24 and 8% less (P < 0.01) observations in the stream and riparian zones than U or UW pastures regardless of pasture size. Off-stream water had little effect on the presence of cows in or near pasture streams regardless of pasture size. In 2011, the probability of cow presence in the stream and riparian zones increased at greater (P < 0.04) rates as ambient temperature increased in U and UW pastures than in 2010. As ambient temperature increased, the probability of cow presence in the stream and riparian zones increased at greater (P < 0.01) rates in small than large pastures. Across pasture sizes, the probability of cow presence in the stream and riparian zone increased less (P < 0.01) with increasing ambient temperatures in R than U and UW pastures. Rates of increase in the probability of cow presence in shade (within 10 m of tree drip lines) in the total pasture with increasing temperatures did not differ between treatments. However, probability of cow presence in riparian shade increased at greater (P < 0.01) rates in small than large pastures. Pasture size was a major factor affecting congregation of cows in or near pasture streams with unrestricted access.

Carcass and meat quality traits of rabbits under heat stress.

PubMed

Zeferino, C P; Komiyama, C M; Fernandes, S; Sartori, J R; Teixeira, P S S; Moura, A S A M T

2013-03-01

Rabbits are very sensitive to heat stress because they have difficulty eliminating excess body heat. The objective of the current study was to evaluate the effects of heat stress on slaughter weight, dressing percentage and carcass and meat quality traits of rabbits from two genetic groups. Ninety-six weaned rabbits were used: half were from the Botucatu genetic group and half were crossbreds between New Zealand White sires and Botucatu does. They were assigned to a completely randomized design in a 2 × 3 factorial arrangement (two genetic groups and three ambient temperatures: 18°C, 25°C and 30°C) and kept under controlled conditions in three environmental chambers from 5 to 10 weeks of age. Slaughter took place at 10 weeks, on 2 consecutive days. Meat quality measurements were made in the longissimus muscle. Actual average ambient temperature and relative humidity in the three chambers were 18.4°C and 63.9%, 24.4°C and 80.2% and 29.6°C and 75.9%, respectively. Purebred rabbits were heavier at slaughter and had heavier commercial and reference carcasses than crossbreds at 30°C; however, no differences between genetic groups for these traits were found at lower temperatures. No genetic group × ambient temperature interaction was detected for any other carcass or meat quality traits. The percentages of distal parts of legs, skin and carcass forepart were higher in crossbred rabbits, indicating a lower degree of maturity at slaughter in this group. The percentage of thoracic viscera was higher in the purebreds. Lightness of the longissimus muscle was higher in the purebreds, whereas redness was higher in the crossbreds. Slaughter, commercial and reference carcass weights and the percentages of thoracic viscera, liver and kidneys were negatively related with ambient temperature. Commercial and reference carcass yields, and the percentage of distal parts of legs, on the other hand, had a positive linear relationship with ambient temperature. Meat redness and yellowness diminished as ambient temperature increased, whereas cooking loss was linearly elevated with ambient temperature. Meat color traits revealed paler meat in the purebreds, but no differences in instrumental texture properties and water-holding capacity between genetic groups. Purebred rabbits were less susceptible to heat stress than the crossbreds. Heat stress resulted in lower slaughter and carcass weights and proportional reductions of organ weights, which contributed to a higher carcass yield. Moreover, it exerted a small, but negative, effect on meat quality traits.

Influence des conditions climatiques saisonnières sur quelques paramètres physiologiques dès boucs Créoles alimentés avec de l'ensilage de banane

NASA Astrophysics Data System (ADS)

Fauconneau, B.; Xande, A.

1986-06-01

Response of three groups of 12 male creole goats (weighing about 10 kg) to environmental variations was tested in Guadeloupe (French West Indies) respectively at three times in the year: end of humid season (October November), dry season (February March) and beginning of humid season (July August). Voluntary free intake of banana silage (silage of mixed green banana, bagassa, wheat bran and urea complemented with molasse) was not significantly affected by climatic variations. Three physiological parameters: rectal temperature, respiratory frequency and cardiac frequency were measured. These parameters were correlated with heat production dependent factors such as metabolic body weight, body weight gain and voluntary free intake. Rectal temperature increased all through the day until sunset and then decreased during the night. Both minimal rectal temperature and daily increase of rectal temperature were correlated with ambient temperature. Cardiac frequency increased during feeding. Generally cardiac frequency seemed to be correlated with activity of animals and so with behavioural response to environmental variations. Respiratory frequency was the most sensitive index of goat response to climate. The daily increase of respiratory frequency was important at the end of the humid season but was not observed in dry season. This increase was dependent on ambient temperature increase but also on air humidity characteristics and air velocity. These points are discussed according to integration of those physiological parameters in thermoregulation.

Estimation of ring tensile properties of steam oxidized Zircaloy-4 fuel cladding under simulated LOCA condition

NASA Astrophysics Data System (ADS)

Shriwastaw, R. S.; Sawarn, Tapan K.; Banerjee, Suparna; Rath, B. N.; Dubey, J. S.; Kumar, Sunil; Singh, J. L.; Bhasin, Vivek

2017-09-01

The present study involves the estimation of ring tensile properties of Indian Pressurised Heavy Water Reactor (IPHWR) fuel cladding made of Zircaloy-4, subjected to experiments under a simulated loss-of-coolant-accident (LOCA) condition. Isothermal steam oxidation experiments were conducted on clad tube specimens at temperatures ranging from 900 to 1200 °C at an interval of 50 °C for different soaking periods with subsequent quenching in water at ambient temperature. The specimens, which survived quenching, were then subjected to ambient temperature ring tension test (RTT). The microstructure was correlated with the mechanical properties. The yield strength (YS) and ultimate tensile strength (UTS) increased initially with rise in oxidation temperature and time duration but then decreased with further increase in oxidation. Ductility is adversely affected with rising oxidation temperature and longer holding time. A higher fraction of load bearing phase and lower oxygen content in it ensures higher residual ductility. Cladding shows almost zero ductility behavior in RIT when load bearing phase fraction is less than 0.72 and its average oxygen concentration is greater than 0.58 wt%.

Volume and structural relaxation in compressed sodium borate glass.

PubMed

Svenson, Mouritz N; Youngman, Randall E; Yue, Yuanzheng; Rzoska, Sylwester J; Bockowski, Michal; Jensen, Lars R; Smedskjaer, Morten M

2016-11-21

The structure and properties of glass can be modified through compression near the glass transition temperature (T g ), and such modified structure and properties can be maintained at ambient temperature and pressure. However, once the compressed glass undergoes annealing near T g at ambient pressure, the modified structure and properties will relax. The challenging question is how the property relaxation is correlated with both the local and the medium-range structural relaxation. In this paper, we answer this question by studying the volume (density) and structural relaxation of a sodium borate glass that has first been pressure-quenched from its T g at 1 GPa, and then annealed at ambient pressure under different temperature-time conditions. Using 11 B MAS NMR and Raman spectroscopy, we find that the pressure-induced densification of the glass is accompanied by a conversion of six-membered rings into non-ring trigonal boron (B III ) units, i.e. a structural change in medium-range order, and an increase in the fraction of tetrahedral boron (B IV ), i.e. a structural change in short-range order. These pressure-induced structural conversions are reversible during ambient pressure annealing near T g , but exhibit a dependence on the annealing temperature, e.g. the ring/non-ring B III ratio stabilizes at different values depending on the applied annealing temperature. We find that conversions between structural units cannot account for the pressure-induced densification, and instead we suggest the packing of structural units as the main densification mechanism.

Oxygen consumption during pouch development of the macropod marsupial Setonix brachyurus

PubMed Central

Shield, John

1966-01-01

1. Measurements of O2 consumption at 9 or 10 temperatures in the 20-40° C ambient temperature range were made on joeys with ages selected to cover the 180-day period of pouch occupancy. 2. The rate of O2 consumption of joeys younger than 100 days increased directly with ambient temperature. 3. After 100 days of age the O2 consumption rate at low temperatures rose and at about 140 days of age a constant rate was maintained over the full ambient temperature range. 4. Heat transfer from joey to mother commenced after 100 days of age. 5. At 150-180 days of age the rate of O2 consumption at 20° C was approximately 12 times greater than at ages less than 100 days. A thermal neutral zone was established in the range 32-36° C by joeys older than 150 days. 6. At the usual pouch temperature of 36·5° C, O2 consumption per unit wet body weight rose from 12 ml./kg.min at birth to 17 ml./kg.min at the end of pouch life. On a unit dry body weight basis it fell from 120 to 56 ml./kg.min. This decline parallels the decrease in growth rate. PMID:5972171

Low temperature-induced DNA hypermethylation attenuates expression of RhAG, an AGAMOUS homolog, and increases petal number in rose (Rosa hybrida).

PubMed

Ma, Nan; Chen, Wen; Fan, Tiangang; Tian, Yaran; Zhang, Shuai; Zeng, Daxing; Li, Yonghong

2015-10-05

Flower development is central to angiosperm reproduction and is regulated by a broad range of endogenous and exogenous stimuli. It has been well documented that ambient temperature plays a key role in controlling flowering time; however, the mechanisms by which temperature regulates floral organ differentiation remain largely unknown. In this study, we show that low temperature treatment significantly increases petal number in rose (Rosa hybrida) through the promotion of stamen petaloidy. Quantitative RT-PCR analysis revealed that the expression pattern of RhAG, a rose homolog of the Arabidopsis thaliana AGAMOUS C-function gene, is associated with low temperature regulated flower development. Silencing of RhAG mimicked the impact of low temperature treatments on petal development by significantly increasing petal number through an increased production of petaloid stamens. In situ hybridization studies further revealed that low temperature restricts its spatial expression area. Analysis of DNA methylation level showed that low temperature treatment enhances the methylation level of the RhAG promoter, and a specific promoter region that was hypermethylated at CHH loci under low temperature conditions, was identified by bisulfite sequencing. This suggests that epigenetic DNA methylation contributes to the ambient temperature modulation of RhAG expression. Our results provide highlights in the role of RhAG gene in petal number determination and add a new layer of complexity in the regulation of floral organ development. We propose that RhAG plays an essential role in rose flower patterning by regulating petal development, and that low temperatures increase petal number, at least in part, by suppressing RhAG expression via enhancing DNA CHH hypermethylation of the RhAG promoter.

High atmospheric temperatures and ‘ambient incubation’ drive embryonic development and lead to earlier hatching in a passerine bird

PubMed Central

Griffith, Simon C.; Mainwaring, Mark C.; Sorato, Enrico; Beckmann, Christa

2016-01-01

Tropical and subtropical species typically experience relatively high atmospheric temperatures during reproduction, and are subject to climate-related challenges that are largely unexplored, relative to more extensive work conducted in temperate regions. We studied the effects of high atmospheric and nest temperatures during reproduction in the zebra finch. We characterized the temperature within nests in a subtropical population of this species in relation to atmospheric temperature. Temperatures within nests frequently exceeded the level at which embryo’s develop optimally, even in the absence of parental incubation. We experimentally manipulated internal nest temperature to demonstrate that an average difference of 6°C in the nest temperature during the laying period reduced hatching time by an average of 3% of the total incubation time, owing to ‘ambient incubation’. Given the avian constraint of laying a single egg per day, the first eggs of a clutch are subject to prolonged effects of nest temperature relative to later laid eggs, potentially increasing hatching asynchrony. While birds may ameliorate the negative effects of ambient incubation on embryonic development by varying the location and design of their nests, high atmospheric temperatures are likely to constitute an important selective force on avian reproductive behaviour and physiology in subtropical and tropical regions, particularly in the light of predicted climate change that in many areas is leading to a higher frequency of hot days during the periods when birds breed. PMID:26998315

Studies on droplet evaporation and combustion in high pressures

NASA Technical Reports Server (NTRS)

Sato, J.

1993-01-01

High pressure droplet evaporation and combustion have been studied up to 15 MPa under normal and microgravity fields. From the evaporation studies, it has been found that in the supercritical environments, the droplet evaporation rate and lifetime take a maximum and a minimum at an ambient pressure over the critical pressure. Its maximum and minimum points move toward the lower ambient pressures if the ambient temperature is increased. It has been found from the combustion studies that the burning life time takes a minimum at an ambient pressure being equal to the critical pressure. It is attributable to both the pressure dependency of the diffusion rate and the droplet evaporation characteristics described above.

Physiological responses to treadmill exercise and ambient temperature in normal and malignant hyperthermia susceptible pigs.

PubMed Central

D'Allaire, S; DeRoth, L

1986-01-01

Ten susceptible and ten resistant pigs to malignant hyperthermia were used to observe the effects of exercise and ambient temperature on selected physiological parameters. Pigs were submitted to a ten minute exercise on a treadmill operating at a speed of 1.8 km/h and inclined to 11 degrees. Exercise in the first group was at an ambient temperature of 14 degrees C, and in the second at 29 degrees C. The right carotid artery was previously cannulated for blood pressure measurements and for repeated blood sampling during exercise. Arterial pressure, heart rate, rectal and cutaneous temperatures were recorded. Levels of cortisol, creatine kinase and its isoenzymes were measured. At 14 degrees C, exercise caused some physiological adjustments in susceptible animals; heart rate, skin temperature and cortisol levels increased (P less than 0.05). In resistant pigs, only the heart rate was elevated significantly following exertional stress at 14 degrees C. Exercise at 29 degrees C produced severe stress and marked physiological changes: heart rate, rectal and skin temperatures and cortisol levels increased significantly in both susceptible and resistant swine. At 29 degrees C, susceptible pigs also had higher levels of serum cortisol, total creatine kinase and MM isoenzyme (P less than 0.05) compared to resistant pigs. The results indicate that, following exertional or thermal stress, susceptible pigs undergo more extensive physiological changes than do resistant pigs. Similar levels of stress prior to slaughter may trigger physiological changes which in the susceptible pigs would likely result in pale, soft exudative myopathy. PMID:3742362

Compression, bend, and tension studies on forged Al67Ti25Cr8 and Al66Ti25Mn(g) L1(2) compounds

NASA Technical Reports Server (NTRS)

Kumar, K. S.; Brown, S. A.; Whittenberger, J. D.

1991-01-01

Cast, homogenized, and isothermally forged aluminum-rich L1(2) compounds Al67Ti25Cr8 and Al66Ti25Mn(g) were tested in compression as a function of temperature and as a function of strain rate at elevated temperatures (1000 K and 1100 K). Three-point bend specimens were tested as a function of temperature in the range 300 K to 873 K. Strain gages glued on the tensile side of the ambient and 473 K specimens enabled direct strain measurements. A number of 'buttonhead' tensile specimens were electro-discharge machined, fine polished, and tested between ambient and 1073 K for yield strength and ductility as a function of temperature. Scanning electron microscope (SEM) examination of fracture surfaces from both the bend and tensile specimens revealed a gradual transition from transgranular cleavage to intergranular failure with increasing temperature.

Boreal and temperate trees show strong acclimation of respiration to warming.

PubMed

Reich, Peter B; Sendall, Kerrie M; Stefanski, Artur; Wei, Xiaorong; Rich, Roy L; Montgomery, Rebecca A

2016-03-31

Plant respiration results in an annual flux of carbon dioxide (CO2) to the atmosphere that is six times as large as that due to the emissions from fossil fuel burning, so changes in either will impact future climate. As plant respiration responds positively to temperature, a warming world may result in additional respiratory CO2 release, and hence further atmospheric warming. Plant respiration can acclimate to altered temperatures, however, weakening the positive feedback of plant respiration to rising global air temperature, but a lack of evidence on long-term (weeks to years) acclimation to climate warming in field settings currently hinders realistic predictions of respiratory release of CO2 under future climatic conditions. Here we demonstrate strong acclimation of leaf respiration to both experimental warming and seasonal temperature variation for juveniles of ten North American tree species growing for several years in forest conditions. Plants grown and measured at 3.4 °C above ambient temperature increased leaf respiration by an average of 5% compared to plants grown and measured at ambient temperature; without acclimation, these increases would have been 23%. Thus, acclimation eliminated 80% of the expected increase in leaf respiration of non-acclimated plants. Acclimation of leaf respiration per degree temperature change was similar for experimental warming and seasonal temperature variation. Moreover, the observed increase in leaf respiration per degree increase in temperature was less than half as large as the average reported for previous studies, which were conducted largely over shorter time scales in laboratory settings. If such dampening effects of leaf thermal acclimation occur generally, the increase in respiration rates of terrestrial plants in response to climate warming may be less than predicted, and thus may not raise atmospheric CO2 concentrations as much as anticipated.

Ambient Temperature, Fuel Economy, Emissions, and Trip Length

DOT National Transportation Integrated Search

1979-08-01

This report examines the relationship among automotive fuel economy, ambient temperature, cold-start trip length, and drive-train component temperatures of four 1977 vehicles. Fuel economy, exhaust emission, and drive-train temperatures were measured...

Experimental evaluation of refrigerant mass charge and ambient air temperature effects on performance of air-conditioning systems

NASA Astrophysics Data System (ADS)

Deymi-Dashtebayaz, Mahdi; Farahnak, Mehdi; Moraffa, Mojtaba; Ghalami, Arash; Mohammadi, Nima

2018-03-01

In this paper the effects of refrigerant charge amount and ambient air temperature on performance and thermodynamic condition of refrigerating cycle in the split type air-conditioner have been investigated. Optimum mass charge is the point at which the energy efficiency ratio (EER) of refrigeration cycle becomes the maximum. Experiments have been conducted over a range of refrigerant mass charge from 540 to 840 g and a range of ambient temperature from 27 to 45 °C, in a 12,000 Btu/h split air-conditioner as case study. The various parameters have been considered to evaluate the cooling rate, energy efficiency ratio (EER), mass charge effect and thermodynamic cycle of refrigeration system with R22 refrigerant gas. Results confirmed that the lack of appropriate refrigerant mass charge causes the refrigeration system not to reach its maximum cooling capacity. The highest cooling capacity achieved was 3.2 kW (11,000 Btu/h). The optimum mass charge and corresponding EER of studied system have been obtained about 640 g and 2.5, respectively. Also, it is observed that EER decreases by 30% as ambient temperature increases from 27 °C to 45 °C. By optimization of the refrigerant mass charge in refrigerating systems, about 785 GWh per year of electric energy can be saved in Iran's residential sector.

Ambient Temperature and Morbidity: A Review of Epidemiological Evidence

PubMed Central

Ye, Xiaofang; Wolff, Rodney; Yu, Weiwei; Vaneckova, Pavla; Pan, Xiaochuan

2011-01-01

Objective: In this paper, we review the epidemiological evidence on the relationship between ambient temperature and morbidity. We assessed the methodological issues in previous studies and proposed future research directions. Data sources and data extraction: We searched the PubMed database for epidemiological studies on ambient temperature and morbidity of noncommunicable diseases published in refereed English journals before 30 June 2010. Forty relevant studies were identified. Of these, 24 examined the relationship between ambient temperature and morbidity, 15 investigated the short-term effects of heat wave on morbidity, and 1 assessed both temperature and heat wave effects. Data synthesis: Descriptive and time-series studies were the two main research designs used to investigate the temperature–morbidity relationship. Measurements of temperature exposure and health outcomes used in these studies differed widely. The majority of studies reported a significant relationship between ambient temperature and total or cause-specific morbidities. However, there were some inconsistencies in the direction and magnitude of nonlinear lag effects. The lag effect of hot temperature on morbidity was shorter (several days) compared with that of cold temperature (up to a few weeks). The temperature–morbidity relationship may be confounded or modified by sociodemographic factors and air pollution. Conclusions: There is a significant short-term effect of ambient temperature on total and cause-specific morbidities. However, further research is needed to determine an appropriate temperature measure, consider a diverse range of morbidities, and to use consistent methodology to make different studies more comparable. PMID:21824855

Effect of season and ambient temperature on outcome of guaiac-based faecal occult blood tests performed for colorectal cancer screening.

PubMed

Hunter, J P; Saratzis, A; Froggatt, P; Harmston, C

2012-09-01

Guaiac-based faecal occult blood tests (gFOBTs) are used in the colorectal cancer screening programme. Recent data suggested that the immunological faecal occult blood test illustrated a variation in positivity according to season and ambient temperature. Our aim was to assess the effect of season and ambient temperature on the positivity rates of the gFOBT during pilot screening for colorectal cancer. Data from the first year of round 1 of the pilot screening programme in Coventry and Warwickshire were analysed. Patients with positive and negative gFOBT samples were included. Patients with spoilt samples or incomplete data were excluded. Of the total of 59513 patients, 30311 were men and 29202 women. Mean age was 56 years. Daily temperature data were provided by the meteorological office. Median exposure of the gFOBT test card was 6 days (range 1-17). Median daily maximum temperature was 14°C. Spring and summer illustrated significantly decreased positivity rates compared with autumn and winter (Pearson's chi-squared test, P<0.001). Mean daily maximum temperature for the test card exposure showed no significant difference in positivity rates (P=0.53). Subgroup analysis revealed a significant reduction in positive samples in the >25°C subgroup (P=0.045). There is a seasonal variation in positivity rates of gFOBTs with increased positivity in spring and summer months. There is no difference in positivity rates in relation to ambient temperature except in subgroup analysis where there is a significant reduction in positivity rates above 25°C. © 2011 The Authors. Colorectal Disease © 2011 The Association of Coloproctology of Great Britain and Ireland.

Metabolic scope and interspecific competition in sculpins of Greenland are influenced by increased temperatures due to climate change.

PubMed

Seth, Henrik; Gräns, Albin; Sandblom, Erik; Olsson, Catharina; Wiklander, Kerstin; Johnsson, Jörgen I; Axelsson, Michael

2013-01-01

Ongoing climate change has led to an increase in sea surface temperatures of 2-4°C on the west coast of Greenland. Since fish are ectothermic, metabolic rate increases with ambient temperature. This makes these animals particularly sensitive to changes in temperature; subsequently any change may influence their metabolic scope, i.e. the physiological capacity to undertake aerobically challenging activities. Any temperature increase may thus disrupt species-specific temperature adaptations, at both the molecular level as well as in behavior, and concomitant species differences in the temperature sensitivity may shift the competitive balance among coexisting species. We investigated the influence of temperature on metabolic scope and competitive ability in three species of marine sculpin that coexist in Greenland coastal waters. Since these species have different distribution ranges, we hypothesized that there should be a difference in their physiological response to temperature; hence we compared their metabolic scope at three temperatures (4, 9 and 14°C). Their competitive ability at the ambient temperature of 9°C was also tested in an attempt to link physiological capacity with behaviour. The Arctic staghorn sculpin, the species with the northernmost distribution range, had a lower metabolic scope in the higher temperature range compared to the other two species, which had similar metabolic scope at the three temperatures. The Arctic staghorn sculpin also had reduced competitive ability at 9°C and may thus already be negatively affected by the current ocean warming. Our results suggest that climate change can have effects on fish physiology and interspecific competition, which may alter the species composition of the Arctic fish fauna.

The effect of ambient temperature on infrared thermographic images of joints in the distal forelimbs of healthy racehorses.

PubMed

Soroko, Maria; Howell, Kevin; Dudek, Krzysztof

2017-05-01

The aim of the study was to describe the dependence on ambient temperature of distal joint temperature at the forelimbs of racehorses. The study also investigated the influence of differing ambient temperatures on the temperature difference between joints: this was measured ipsilaterally (i.e. between the carpal and fetlock joints along each forelimb) and contralaterally (i.e. between the same joints of the left and right forelimbs). Sixty-four healthy racehorses were monitored over 10 months. At each session, three thermographic images were taken of the dorsal, lateral and medial aspects of the distal forelimbs. Temperature measurements were made from regions of interest (ROIs) covering the carpal and fetlock joints. There was a strong correlation between ambient temperature and absolute joint temperature at all ROIs. The study also observed a moderate correlation between ambient temperature and the ipsilateral temperature differences between joints when measured from the medial and lateral aspects. No significant correlation was noted when measured dorsally. The mean contralateral temperature differences between joints were all close to 0°C. The data support previous reports that the temperature distribution between the forelimbs of the healthy equine is generally symmetric, although some horses differ markedly from the average findings. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of water addition to a total mixed ration on feed temperature, feed intake, sorting behavior, and milk production of dairy cows.

PubMed

Felton, C A; DeVries, T J

2010-06-01

The objective of this study was to determine the effects of water addition to a high-moisture total mixed ration (TMR) on feed temperature, feed intake, feed sorting behavior, and milk production of dairy cows. Twelve lactating Holstein cows (155.8+/-60.1 DIM), individually fed once daily at 1000 h, were exposed to 3 diets in a Latin square design with 28-d treatment periods. Diets had the same ingredient composition [30.9% corn silage, 30.3% alfalfa haylage, 21.2% high-moisture corn, and 17.6% protein supplement; dry matter (DM) basis] and differed only in DM concentration, which was reduced by the addition of water. Treatment diets averaged 56.3, 50.8, and 44.1% DM. The study was conducted between May and August when environmental temperature was 18.2+/-3.6 degrees C and ambient temperature in the barn was 24.4+/-3.3 degrees C. Dry matter intake (DMI) was monitored for each animal for the last 14 d of each treatment period. For the final 7 d of each period, milk production was monitored, feed temperature and ambient temperature and humidity were recorded (daily at 1000, 1300, and 1600 h), and fresh feed and orts were sampled for determination of sorting. For the final 4 d of each period, milk samples were taken for composition analysis. Samples taken for determining sorting were separated using a Penn State Particle Separator that had 3 screens (19, 8, and 1.18 mm) and a bottom pan, resulting in 4 fractions (long, medium, short, and fine). Sorting was calculated as the actual intake of each particle size fraction expressed as a percentage of the predicted intake of that fraction. Greater amounts of water added to the TMR resulted in greater increases in feed temperature in the hours after feed delivery, greater sorting against long particles, and decreased DMI, reducing the overall intake of starch and neutral detergent fiber. Milk production and composition were not affected by the addition of water to the TMR. Efficiency of production of milk was, however, increased with greater amounts of water added to the TMR. The increases in feed temperature in the hours after feed delivery were enhanced by higher ambient temperatures; this may be indicative of feed spoilage and thus may have contributed to the reduced DMI observed. Overall, these results suggest that the addition of water to high-moisture TMR (less than 60% DM) containing primarily haylage and silage forage sources will not always discourage cows from sorting, but rather may increase this behavior and limit the nutrient consumption of cows, particularly when ambient temperature is high. 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Trailer temperature and humidity during winter transport of cattle in Canada and evaluation of indicators used to assess the welfare of cull beef cows before and after transport.

PubMed

Goldhawk, C; Janzen, E; González, L A; Crowe, T; Kastelic, J; Kehler, C; Siemens, M; Ominski, K; Pajor, E; Schwartzkopf-Genswein, K S

2015-07-01

The current study evaluated 17 loads of cull beef cows transported in Canadian winter conditions to assess in-transit temperature and humidity, evaluation of events during loading and unloading, and animal condition and bruising. Regardless of the use of boards to block ventilation holes in trailers, temperatures were higher within trailers than at ambient locations during both travel and stationary periods (P < 0.01). Boarding was associated with smaller differences in trailer temperature, compared with ambient conditions, while the trailer was traveling at highway speeds versus when trailers were stationary (P < 0.01). Moisture levels within trailers were not different from ambient conditions when loads using boarding were traveling (P < 0.01), whereas loads without boarding had a larger difference (P < 0.01). The moisture within trailers relative to ambient conditions increased when trailers were stationary compared with traveling when boarding was used (P < 0.01). The majority of cattle transported were in good body condition (97.4% within BCS of 2 to 3.5) and had calm temperaments (96.7%). Although all comparisons were made, only the doghouse compartment had an increased risk of severe bruising compared with all other compartments (odds ratio [95% confidence interval]: 3.0 [1.6–5.5], 3.7 [2.1–6.4], 2.2 [1.3–3.7] and 3.8 [1.5–9.6] in comparison with the back, belly, deck, and nose compartments, respectively; P < 0.05). Increasing the duration of waiting to unload 30 min relative to a 1 h duration increased the odds of severe bruising by 1.18 times (95% confidence interval: 1.09–1.29; P < 0.01). Scoring systems that have been developed for auditing unloading of cattle had limited variation across loads at both loading and unloading. Pretransport assessment of animal condition using the American Meat Institute’s compromised animal score was the only scoring system that was consistent with posttransport scores. We inferred from the temperature and humidity data in the current study that under commercial conditions, boarding may increase ventilation within trailers during travel and decrease ventilation during stationary periods. The current study provides the first indication that issues in Canadian cull cow transport may be related to pretransport animal condition and management of unloading.

Thirty Stage Annular Centrifugal Contactor Thermal Profile Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

David H. Meikrantz; Troy G. Garn; Jack D. Law

2010-02-01

A thirty stage 5 cm annular centrifugal contactor cascade has been assembled and tested to obtain thermal profiles during both ambient and heated input conditions of operation. Thermocouples were installed on every stage as well as feed inputs and Real-time data was taken during experiments lasting from two to eight hours at total flow rates of 0.5 to 1.4 liters per minute. Ambient temperature profile results show that only a small amount of heat is generated by the mechanical energy of the contactors. Steady state temperature profiles mimic the ambient temperature of the lab but are higher toward the middlemore » of the cascade. Heated inlet solutions gave temperature profiles with smaller temperature gradients, more driven by the temperature of the inlet solutions than ambient lab temperature. Temperature effects of solution mixing, even at rotor speeds of 4000 rpm, were not measurable.« less

Seasonality of diarrheagenic Escherichia coli pathotypes in the US students acquiring diarrhea in Mexico.

PubMed

Paredes-Paredes, Mercedes; Okhuysen, Pablo C; Flores, Jose; Mohamed, Jamal A; Padda, Ranjit S; Gonzalez-Estrada, Alexei; Haley, Clinton A; Carlin, Lily G; Nair, Parvathy; DuPont, Herbert L

2011-01-01

Up to 60% of the US visitors to Mexico develop travelers' diarrhea (TD). In Mexico, rates of diarrhea have been associated with the rainy season and increase in ambient temperature. However, the seasonality of the various diarrheagenic Escherichia coli pathotypes in travelers has not been well described. A study was undertaken to determine if ambient temperature and rainfall have an impact on the acquisition of TD due to different diarrheagenic E coli pathotypes in Mexico. We conducted a cohort study of the US adult students traveling to Cuernavaca, Mexico, who were followed during their stay and provided a stool sample with the onset of TD. The presence of E coli was analyzed by a direct fecal multiplex polymerase chain reaction for common E coli pathotypes including enterotoxigenic, enteropathogenic, enteroinvasive, shiga toxin-producing, and enteroaggregative E coli (ETEC, EPEC, EIEC, STEC, and EAEC respectively). The presence of pathotypes was correlated with daily rainfall, average, maximum, and minimum temperatures. A total of 515 adults were enrolled from January 2006 to February 2007. The weekly attack rate of TD for newly arrived travelers was lower in the winter months (range 6.8%-16.3%) than in summer months (range 11.5%-25%; p = 0.05). The rate of ETEC infection increased by 7% for each degree centigrade increase in weekly ambient temperature (p = 0.003). In contrast, EPEC and EAEC were identified in similar proportions during the winter and summer seasons. Temperature variations in central Mexico influenced the rate of ETEC but not EAEC-associated diarrhea in the US visitors. This epidemiological finding could influence seasonal recommendations for the use of ETEC vaccines in Mexico. © 2011 International Society of Travel Medicine.

Current and Projected Burden of Disease From High Ambient Temperature in Korea.

PubMed

Chung, Soo Eun; Cheong, Hae-Kwan; Park, Jae-Hyun; Kim, Jong-Hun; Han, Hyunjin

2017-10-01

The objective of the present study was to estimate the current and projected burden of disease from high ambient temperature using population-based data sources of nationwide mortality and morbidity in Korea. Disability-adjusted life years (DALY) were estimated using noninjury-related deaths, and cerebrovascular and cardiovascular diseases from recently released nationwide health and mortality databases. Years of life lost and years lost due to disability were measured based on the point prevalence and number of deaths during the study period. Future DALY attributable to heat waves were estimated from projected populations, and temperature predictions for the years 2030 and 2050 were under Representative Concentration Pathways (RCP) 4.5 and 8.5 with summertime temperatures above threshold. Relative risks (RR) of total mortality and of cardiovascular disease were 1.02 (95% CI, 1.01, 1.02) and 1.08 (95% CI, 1.06, 1.09) for each 1°C increase in temperature above threshold, respectively. The morbidity of heat-related disease was RR 1.67 (95% CI, 1.64, 1.68) for each 1°C increase in temperature above threshold. DALY for all-cause death were 0.49 DALY/1000 in 2011, 0.71 (0.71) DALY/1000 in 2030 and 0.77 (1.72) DALY/1000 in 2050 based on RCP 4.5 (RCP 8.5). DALY for cardio- and cerebrovascular diseases were 1.24 DALY/1000 in 2011, 1.63 (1.82) DALY/1000 in 2030, and 1.76 (3.66) DALY/1000 in 2050 based on RCP 4.5 (RCP 8.5). Future excess mortality due to high ambient temperature is expected to be profound in Korea. Efforts to mitigate climate change can provide substantial health benefits via reducing heat-related mortality.

Lunar and temperature effects on activity of free-living desert hamsters ( Phodopus roborovskii, Satunin 1903)

NASA Astrophysics Data System (ADS)

Scheibler, Elke; Roschlau, Corinna; Brodbeck, David

2014-10-01

Time management of truly wild hamsters was investigated in their natural habitat in Alashan desert, Inner Mongolia, China during summer of 2009, 2010, and 2012. Duration of activity outside their burrows, duration of foraging walks, and nocturnal inside stays were analyzed with the aim to elucidate impact of moon, ambient, and soil temperature. Animal data were determined using radio frequency identification (RFID) technique; for that purpose, individuals were caught in the field and marked with passive transponders. Their burrows were equipped with integrated microchip readers and photosensors for the detection of movements into or out of the burrow. Lunar impact was analyzed based on moon phase (full, waning, new, and waxing moons) and moon disk size. A prolongation of aboveground activity was shown with increasing moon disk size (Spearman ρ = 0.237; p = 0.025) which was caused by earlier onsets (ρ =-0.161; p = 0.048); additionally, foraging walks took longer (Pearson r = 0.037; p = 0.037). Temperature of different periods of time was analyzed, i.e., mean of whole day, of the activity phase, minimum, and maximum. Moreover, this was done for the current day and the previous 3 days. Overall, increasing ambient and soil temperatures were associated with shortening of activity by earlier offsets of activity and shorter nocturnal stays inside their burrows. Most influential temperatures for activity duration were the maximum ambient temperature, 3 days before (stepwise regression analysis R = 0.499; R 2 = 0.249; F = 7.281; p = 0.013) and soil temperature during activity phase, 1 day before ( R = 0.644; R 2 = 0.283; F = 7.458; p = 0.004).

Particulate matter air pollution and ambient temperature: opposing effects on blood pressure in high-risk cardiac patients.

PubMed

Giorgini, Paolo; Rubenfire, Melvyn; Das, Ritabrata; Gracik, Theresa; Wang, Lu; Morishita, Masako; Bard, Robert L; Jackson, Elizabeth A; Fitzner, Craig A; Ferri, Claudio; Brook, Robert D

2015-10-01

Fine particulate matter air pollution (PM2.5) and extreme temperatures have both been associated with alterations in blood pressure (BP). However, few studies have evaluated their joint haemodynamic actions among individuals at high risk for cardiovascular events. We assessed the effects of short-term exposures during the prior week to ambient PM2.5 and outdoor temperature levels on resting seated BP among 2078 patients enrolling into a cardiac rehabilitation programme at the University of Michigan (from 2003 to 2011) using multiple linear regression analyses adjusting for age, sex, BMI, ozone and the same-day alternate environmental factor (i.e. PM2.5 or temperature). Mean PM2.5 and temperature levels were 12.6 ± 8.2 μg/m and 10.3 ± 10.4°C, respectively. Each standard deviation elevation in PM2.5 concentration during lag days 4-6 was associated with significant increases in SBP (2.1-3.5 mmHg) and DBP (1.7-1.8 mmHg). Conversely, higher temperature levels (per 10.4°C) during lag days 4-6 were associated with reductions in both SBP (-3.6 to -2.3 mmHg) and DBP (-2.5 to -1.8 mmHg). There was little evidence for consistent effect modification by other covariates (e.g. demographics, seasons, medication usage). Short-term exposures to PM2.5, even at low concentrations within current air quality standards, are associated with significant increases in BP. Contrarily, higher ambient temperatures prompt the opposite haemodynamic effect. These findings demonstrate that both ubiquitous environmental exposures have clinically meaningful effects on resting BP among high-risk cardiac patients.

Solid-state Graft Copolymer Electrolytes for Lithium Battery Applications

PubMed Central

Hu, Qichao; Caputo, Antonio; Sadoway, Donald R.

2013-01-01

Battery safety has been a very important research area over the past decade. Commercially available lithium ion batteries employ low flash point (<80 °C), flammable, and volatile organic electrolytes. These organic based electrolyte systems are viable at ambient temperatures, but require a cooling system to ensure that temperatures do not exceed 80 °C. These cooling systems tend to increase battery costs and can malfunction which can lead to battery malfunction and explosions, thus endangering human life. Increases in petroleum prices lead to a huge demand for safe, electric hybrid vehicles that are more economically viable to operate as oil prices continue to rise. Existing organic based electrolytes used in lithium ion batteries are not applicable to high temperature automotive applications. A safer alternative to organic electrolytes is solid polymer electrolytes. This work will highlight the synthesis for a graft copolymer electrolyte (GCE) poly(oxyethylene) methacrylate (POEM) to a block with a lower glass transition temperature (Tg) poly(oxyethylene) acrylate (POEA). The conduction mechanism has been discussed and it has been demonstrated the relationship between polymer segmental motion and ionic conductivity indeed has a Vogel-Tammann-Fulcher (VTF) dependence. Batteries containing commercially available LP30 organic (LiPF6 in ethylene carbonate (EC):dimethyl carbonate (DMC) at a 1:1 ratio) and GCE were cycled at ambient temperature. It was found that at ambient temperature, the batteries containing GCE showed a greater overpotential when compared to LP30 electrolyte. However at temperatures greater than 60 °C, the GCE cell exhibited much lower overpotential due to fast polymer electrolyte conductivity and nearly the full theoretical specific capacity of 170 mAh/g was accessed. PMID:23963203

Solid-state graft copolymer electrolytes for lithium battery applications.

PubMed

Hu, Qichao; Caputo, Antonio; Sadoway, Donald R

2013-08-12

Battery safety has been a very important research area over the past decade. Commercially available lithium ion batteries employ low flash point (< 80 °C), flammable, and volatile organic electrolytes. These organic based electrolyte systems are viable at ambient temperatures, but require a cooling system to ensure that temperatures do not exceed 80 °C. These cooling systems tend to increase battery costs and can malfunction which can lead to battery malfunction and explosions, thus endangering human life. Increases in petroleum prices lead to a huge demand for safe, electric hybrid vehicles that are more economically viable to operate as oil prices continue to rise. Existing organic based electrolytes used in lithium ion batteries are not applicable to high temperature automotive applications. A safer alternative to organic electrolytes is solid polymer electrolytes. This work will highlight the synthesis for a graft copolymer electrolyte (GCE) poly(oxyethylene) methacrylate (POEM) to a block with a lower glass transition temperature (Tg) poly(oxyethylene) acrylate (POEA). The conduction mechanism has been discussed and it has been demonstrated the relationship between polymer segmental motion and ionic conductivity indeed has a Vogel-Tammann-Fulcher (VTF) dependence. Batteries containing commercially available LP30 organic (LiPF6 in ethylene carbonate (EC):dimethyl carbonate (DMC) at a 1:1 ratio) and GCE were cycled at ambient temperature. It was found that at ambient temperature, the batteries containing GCE showed a greater overpotential when compared to LP30 electrolyte. However at temperatures greater than 60 °C, the GCE cell exhibited much lower overpotential due to fast polymer electrolyte conductivity and nearly the full theoretical specific capacity of 170 mAh/g was accessed.

Temperature prediction of space flight experiments by computer thermal analysis

NASA Technical Reports Server (NTRS)

Birdsong, M. B.; Luttges, M. W.

1994-01-01

Life sciences experiments are especially sensitive to temperature. A small temperature difference between otherwise identical samples can cause various differences in biological reaction rates. Knowledge of experimental temperatures and temperature histories help to distinguish the effects of microgravity and temperature on spaceflight experiments compared to ground based studies, and allow appropriate controls and sensitivity tests. Up to the present time, the Orbiter (Space Shuttle) has not generally provided temperature measurement instrumentation inside ambient lockers located in the Mid-deck of the Orbiter, or inside similar facilities such as Spacehab and Spacelab, but many pieces of hardware do have temperature recording capability. Most of these temperatures, however, have only been roughly measured or estimated. Such reported experimental temperatures, while accurate within a range of several degrees Celsius, are of limited utility to biological researchers. The temperature controlled lockers used in spaceflight, such as Commerical-Refrigeration Incubation Modules (C-R/IMs), severely reduce the mass and volume available for test samples and do not necessarily provide uniform thermal environments. While these test carriers avoid some of the experimental temperature variations of the ambient lockers, the number of samples which can be accommodated in these temperature controlled units is limited. In the present work, improved models of thermal prediction and control were sought. Temperatures are predicted by thermal analysis software using empirical temperatures recorded during STS-57. These temperatures are compared to data recorded throughout the mission using Ambient Temperature Recorders (ATRs) located within several payload lockers. Additional test cases are undertaken using controlled ground experiments to more precisely determine the reliability of the thermal model. The approach presented should increase the utility of various spaceflight carriers in the support of biological and material science research and ground control studies done in preparation for flight.

Temperature prediction of space flight experiments by computer thermal analysis.

PubMed

Birdsong, M B; Luttges, M W

1995-02-01

Life sciences experiments are especially sensitive to temperature. A small temperature difference between otherwise identical samples can cause various differences in biological reaction rates. Knowledge of experimental temperatures and temperature histories help to distinguish the effects of microgravity and temperature on spaceflight experiments compared to ground based studies, and allow appropriate controls and sensitivity tests. Up to the present time, the Orbiter (Space Shuttle) has not generally provided temperature measurement instrumentation inside ambient lockers located in the Mid-deck of the Orbiter, or inside similar facilities such as Spacehab and Spacelab, but many pieces of hardware do have temperature recording capability. Most of these temperatures, however, have only been roughly measured or estimated. Such reported experimental temperatures, while accurate within a range of several degrees Celsius, are of limited utility to biological researchers. The temperature controlled lockers used in spaceflight, such as Commercial-Refrigeration Incubation Modules (C-R/IMs), severely reduce the mass and volume available for test samples and do not necessarily provide uniform thermal environments. While these test carriers avoid some of the experimental temperature variations of the ambient lockers, the number of samples which can be accommodated in these temperature controlled units is limited. In the present work, improved models of thermal prediction and control were sought. Temperatures are predicted by thermal analysis software using empirical temperatures recorded during STS-57. These temperatures are compared to data recorded throughout the mission using Ambient Temperature Recorders (ATRs) located within several payload lockers. Additional test cases are undertaken using controlled ground experiments to more precisely determine the reliability of the thermal model. The approach presented should increase the utility of various spaceflight carriers in the support of biological and material science research and ground control studies done in preparation for flight.

Temperature changes, temperature extremes, and their relationship to emergency department visits and hospitalizations for sickle cell crisis.

PubMed

Smith, Wally R; Coyne, Patrick; Smith, Virginia S; Mercier, Bruce

2003-09-01

Weather changes are among the proposed precursors of painful sickle cell crises. However, epidemiologic data are mixed regarding the relationship between ambient temperature and crisis frequency. To study this relationship among a local sickle cell disease population, emergency department (ED) visits and admissions were evaluated in adults with sickle cell crisis as the primary diagnosis at a major teaching hospital in a temperate climate. Official daily ambient temperatures (average for that day) were obtained from the National Climate Data Center for the days patients visited the ED or were hospitalized, and for 24 or 48 hours prior. Daily ED visit counts and admission counts were correlated with the visit/admission day's ambient temperature, with the ambient temperature 24 hours before admission, and with the magnitude of change in daily ambient temperature over the prior 24 or 48 hours. For all correlations, statistical significance was defined as a p value of <0.01 and clinical significance was defined as a moderate or greater correlation, absolute value of r >/= 0.30. ED visits or admissions correlated statistically, but not clinically, with daily temperatures. On days when temperatures were <32 degrees F or >80 degrees F, these correlations were statistically significant, but clinical significance was variable. ED visits or admissions correlated only statistically with temperatures 24 hours prior, even on days when temperatures were <32 degrees F. When temperatures were >80 degrees F, the correlations were statistically significant, but there was a reverse, clinically significant correlation between admissions and temperatures. Finally, only statistically significant correlations were found between ED visits or admissions and change in temperature over the prior 24 or 48 hours. Weak or inconsistent confirmation of a relationship was found between daily ambient temperatures and ED visits or hospital admissions for sickle cell crises.

Disturbances in Pro-Oxidant-Antioxidant Balance after Passive Body Overheating and after Exercise in Elevated Ambient Temperatures in Athletes and Untrained Men

PubMed Central

Pilch, Wanda; Szygula, Zbigniew; Tyka, Anna K.; Palka, Tomasz; Tyka, Aleksander; Cison, Tomasz; Pilch, Pawel; Teleglow, Aneta

2014-01-01

The aim of the study was to investigate pro-oxidant-antioxidant balance in two series of examinations with two types of stressors (exogenous heat and the combined exogenous and endogenous heat) in trained and untrained men. The exogenous stressor was provided by Finnish sauna session, whereas the combined stressor was represented by the exercise in elevated ambient temperature. The men from the two groups performed the physical exercise on a cycle ergometer with the load of 53±2% maximal oxygen uptake at the temperature of 33±1°C and relative humidity of 70% until their rectal temperature rose by 1.2°C. After a month from completion of the exercise test the subjects participated in a sauna bathing session with the temperature of 96±2°C, and relative humidity of 16±5%. 15-minutes heating and 2-minute cool-down in a shower with the temperature of 20°C was repeated until rectal temperature rose by 1.2°C compared to the initial value. During both series of tests rectal temperature was measured at 5-minute intervals. Before both series of tests and after them body mass was measured and blood samples were taken for biochemical tests. Serum total protein, serum concentration of lipid peroxidation products and serum antioxidants were determined. The athletes were characterized by higher level of antioxidant status and lower concentration of lipid peroxidation products. Physical exercise at elevated ambient temperature caused lower changes in oxidative stress indices compared to sauna bathing. Sauna induced a shift in pro-oxidant-antioxidant balance towards oxidation, which was observed less intensively in the athletes compared to the untrained men. This leads to the conclusion that physical exercise increases tolerance to elevated ambient temperature and oxidative stress. PMID:24465535

RNA-seq analysis of broiler liver transcriptome reveals novel responses to high ambient temperature.

PubMed

Coble, Derrick J; Fleming, Damarius; Persia, Michael E; Ashwell, Chris M; Rothschild, Max F; Schmidt, Carl J; Lamont, Susan J

2014-12-10

In broilers, high ambient temperature can result in reduced feed consumption, digestive inefficiency, impaired metabolism, and even death. The broiler sector of the U.S. poultry industry incurs approximately $52 million in heat-related losses annually. The objective of this study is to characterize the effects of cyclic high ambient temperature on the transcriptome of a metabolically active organ, the liver. This study provides novel insight into the effects of high ambient temperature on metabolism in broilers, because it is the first reported RNA-seq study to characterize the effect of heat on the transcriptome of a metabolic-related tissue. This information provides a platform for future investigations to further elucidate physiologic responses to high ambient temperature and seek methods to ameliorate the negative impacts of heat. Transcriptome sequencing of the livers of 8 broiler males using Illumina HiSeq 2000 technology resulted in 138 million, 100-base pair single end reads, yielding a total of 13.8 gigabases of sequence. Forty genes were differentially expressed at a significance level of P-value < 0.05 and a fold-change ≥ 2 in response to a week of cyclic high ambient temperature with 27 down-regulated and 13 up-regulated genes. Two gene networks were created from the function-based Ingenuity Pathway Analysis (IPA) of the differentially expressed genes: "Cell Signaling" and "Endocrine System Development and Function". The gene expression differences in the liver transcriptome of the heat-exposed broilers reflected physiological responses to decrease internal temperature, reduce hyperthermia-induced apoptosis, and promote tissue repair. Additionally, the differential gene expression revealed a physiological response to regulate the perturbed cellular calcium levels that can result from high ambient temperature exposure. Exposure to cyclic high ambient temperature results in changes at the metabolic, physiologic, and cellular level that can be characterized through RNA-seq analysis of the liver transcriptome of broilers. The findings highlight specific physiologic mechanisms by which broilers reduce the effects of exposure to high ambient temperature. This information provides a foundation for future investigations into the gene networks involved in the broiler stress response and for development of strategies to ameliorate the negative impacts of heat on animal production and welfare.

Vertical profiles reveal impact of ozone and temperature on carbon assimilation of Betula pendula and Populus tremula.

PubMed

Mäenpää, Maarit; Riikonen, Johanna; Kontunen-Soppela, Sari; Rousi, Matti; Oksanen, Elina

2011-08-01

Rising temperature and tropospheric ozone (O(3)) concentrations are likely to affect carbon assimilation processes and thus the carbon sink strength of trees. In this study, we investigated the joint action of elevated ozone and temperature on silver birch (Betula pendula) and European aspen (Populus tremula) saplings in field conditions by combining free-air ozone exposure (1.2 × ambient) and infrared heaters (ambient +1.2 °C). At leaf level measurements, elevated ozone decreased leaf net photosynthesis (P(n)), while the response to elevated temperature was dependent on leaf position within the foliage. This indicates that leaf position has to be taken into account when leaf level data are collected and applied. The ozone effect on P(n) was partly compensated for at elevated temperature, showing an interactive effect of the treatments. In addition, the ratio of photosynthesis to stomatal conductance (P(n)/g(s) ratio) was decreased by ozone, which suggests decreasing water use efficiency. At the plant level, the increasing leaf area at elevated temperature resulted in a considerable increase in photosynthesis and growth in both species.

Comparative analysis on inactivation kinetics of between piezotolerant and piezosensitive mutant strains of Saccharomyces cerevisiae under combinations of high hydrostatic pressure and temperature.

PubMed

Nomura, Kazuki; Kuwabara, Yuki; Kuwabara, Wataru; Takahashi, Hiroyuki; Nakajima, Kanako; Hayashi, Mayumi; Iguchi, Akinori; Shigematsu, Toru

2017-12-01

We previously obtained a pressure-tolerant (piezotolerant) and a pressure sensitive (piezosensitive) mutant strain, under ambient temperature, from Saccharomyces cerevisiae strain KA31a. The inactivation kinetics of these mutants were analyzed at 150 to 250MPa with 4 to 40°C. By a multiple regression analysis, the pressure and temperature dependency of the inactivation rate constants k values of both mutants, as well as the parent strain KA31a, were well approximated with high correlation coefficients (0.92 to 0.95). For both mutants, as well as strain KA31a, the lowest k value was shown at a low pressure levels with around ambient temperature. The k value approximately increased with increase in pressure level, and with increase and decrease in temperature. The piezosensitive mutant strain a924E1 showed piezosensitivity at all pressure and temperature levels, compared with the parent strain KA31a. In contrast, the piezotolerant mutant strain a2568D8 showed piezotolerance at 4 to 20°C, but did not show significant piezotolerance at 40°C. These results of the variable influence of temperature on pressure inactivation of these strains would be important for better understanding of piezosensitive and piezotolerant mechanisms, as well as the pressure inactivation mechanism of S. cerevisiae. Copyright © 2017 Elsevier B.V. All rights reserved.

Activation of Neurokinin 3 Receptors in the Median Preoptic Nucleus Decreases Core Temperature in the Rat

PubMed Central

Dacks, Penny A.; Krajewski, Sally J.

2011-01-01

Estrogens have pronounced effects on thermoregulation, as illustrated by the occurrence of hot flushes secondary to estrogen withdrawal in menopausal women. Because neurokinin B (NKB) gene expression is markedly increased in the infundibular (arcuate) nucleus of postmenopausal women, and is modulated by estrogen withdrawal and replacement in multiple species, we have hypothesized that NKB neurons could play a role in the generation of flushes. There is no information, however, on whether the primary NKB receptor [neurokinin 3 receptor (NK3R)] modulates body temperature in any species. Here, we determine the effects of microinfusion of a selective NK3R agonist (senktide) into the rat median preoptic nucleus (MnPO), an important site in the heat-defense pathway. Senktide microinfusion into the rat MnPO decreased core temperature in a dose-dependent manner. The hypothermia induced by senktide was similar in ovariectomized rats with and without 17β-estradiol replacement. The hypothermic effect of senktide was prolonged in rats exposed to an ambient temperature of 29.0 C, compared with 21.5 C. Senktide microinfusion also altered tail skin vasomotion in rats exposed to an ambient temperature of 29.0 but not 21.5 C. Comparisons of the effects of senktide at different ambient temperatures indicated that the hypothermia was not secondary to thermoregulatory failure or a reduction in cold-induced thermogenesis. Other than a very mild increase in drinking, senktide microinfusion did not affect behavior. Terminal fluorescent dextran microinfusion showed targeting of the MnPO and adjacent septum, and immunohistochemical studies revealed that senktide induced a marked increase in Fos-activation in the MnPO. Because MnPO neurons expressed NK3R-immunoreactivity, the induction of MnPO Fos by senktide is likely a direct effect. By demonstrating that NK3R activation in the MnPO modulates body temperature, these studies support the hypothesis that hypothalamic NKB neurons could be involved in the generation of menopausal flushes. PMID:22028440

40 CFR 1042.515 - Test procedures related to not-to-exceed standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... altitudes up to 1,100 feet above sea level. (2) Ambient air temperature must be between 13 and 35 °C (or... the engine). (3) Ambient water temperature must be between 5 and 27 °C. (4) Ambient humidity must be... operating temperatures. For example, this would include only engine operation after starting and after the...

Microbiological Studies of Semi-Preserved Natural Condiments Paste Stored in Refrigerator and Ambient Temperature

NASA Astrophysics Data System (ADS)

Dien, H. A.; Montolalu, R. I.; Mentang, F.; Mandang, A. S. K.; Rahmi, A. D.; Berhimpon, S.

2018-01-01

The aims of this studies were to prepare juice and raw condiment to be come semipreserve pastes, and to do microbial assessments on the both pastes during storing in refrigerator and ambient temperatures. For both pastes in refrigerator, samples were taken at 0, 2, 4, 5, 6, 8, 10, 15, 20, 25, and 30 days, and in ambient temperature samples were taken at 0, 1, 2, 3, 4, and 6 days. Assessment were done for TPC, total coliform and E. coli, Salmonella sp, Staphylococcus sp., Vibrio sp., pH and water content. The results shown that juice paste stored in refrigerator still good until 30 days (TPC 1,5x104 CFU/g), and in ambient temperature still good until 6 days (2x104 CFU/g). Condiment paste stored in refrigerator still good until 30 days (6.5x103 CFU/g), and in ambient temperature still good until 6 days (1.17x104 CFU/g). However, recommended that condiment paste stored in ambient temperature only until 4 days (7.3x103CFU/g), while that juice paste until 5 days (7.8x103CFU/g). There were no pathogenic bacteria found in all samples.

Seawater Acidification and Elevated Temperature Affect Gene Expression Patterns of the Pearl Oyster Pinctada fucata

PubMed Central

Liu, Wenguang; Huang, Xiande; Lin, Jianshi; He, Maoxian

2012-01-01

Oceanic uptake of anthropogenic carbon dioxide results in decrease in seawater pH and increase in temperature. In this study, we demonstrated the synergistic effects of elevated seawater temperature and declined seawater pH on gene expression patterns of aspein, calmodulin, nacrein, she-7-F10 and hsp70 in the pearl oyster Pinctada fucata. Under ‘business-as-usual’ scenarios, four treatments were examined: (1) ambient pH (8.10) and ambient temperature (27°C) (control condition), (2) ambient pH and elevated temperature (+3°C), (3) declined pH (7.70) and ambient temperature, (4) declined pH and elevated temperature. The results showed that under warming and acidic seawater conditions, expression of aspein and calmodulin showed no significant differences among different time point in condition 8.10 T. But the levels of aspein and calmodulin in conditions 8.10 T+3, 7.70 T and 7.70 T+3, and levels of nacrein, she-7-F10 in all the four treatments changed significantly. Low pH and pH×temperature interaction influenced the expression of aspein and calmodulin significantly after hours 48 and 96. Significant effects of low pH and pH×temperature interaction on the expression of nacrein were observed at hour 96. The expression level of she-7-F10 was affected significantly by pH after hours 48 and 96. The expression of hsp70 was significantly affected by temperature, pH, temperature×pH interaction at hour 6, and by temperature×pH interaction at hour 24. This study suggested that declined pH and pH×temperature interaction induced down regulation of calcification related genes, and the interaction between declined seawater pH and elevated temperature caused up regulation of hsp70 in P. facata. These results demonstrate that the declined seawater pH and elevated temperature will impact the physiological process, and potentially the adaptability of P. fucata to future warming and acidified ocean. PMID:22438983

Type 2 diabetes, but not obesity, prevalence is positively associated with ambient temperature.

PubMed

Speakman, John R; Heidari-Bakavoli, Sahar

2016-08-01

Cold exposure stimulates energy expenditure and glucose disposal. If these factors play a significant role in whole body energy balance, and glucose homeostasis, it is predicted that both obesity and type 2 diabetes prevalence would be lower where it is colder. Previous studies have noted connections between ambient temperature and obesity, but the direction of the effect is confused. No previous studies have explored the link of type 2 diabetes to ambient temperature. We used county level data for obesity and diabetes prevalence across the mainland USA and matched this to county level ambient temperature data. Average ambient temperature explained 5.7% of the spatial variation in obesity and 29.6% of the spatial variation in type 2 diabetes prevalence. Correcting the type 2 diabetes data for the effect of obesity reduced the explained variation to 26.8%. Even when correcting for obesity, poverty and race, ambient temperature explained 12.4% of the variation in the prevalence of type 2 diabetes, and this significant effect remained when latitude was entered into the model as a predictor. When obesity prevalence was corrected for poverty and race the significant effect of temperature disappeared. Enhancing energy expenditure by cold exposure will likely not impact obesity significantly, but may be useful to combat type 2 diabetes.

Antioxidant enzyme activities, plasma hormone levels and serum metabolites of finishing broiler chickens reared under high ambient temperature and fed lemon and orange peel extracts and Curcuma xanthorrhiza essential oil.

PubMed

Akbarian, A; Golian, A; Kermanshahi, H; De Smet, S; Michiels, J

2015-02-01

The negative effects of high ambient temperature during some months of the year on poultry production have been of great concern in many countries. Dietary modifications are among the most practical ways to alleviate the effects of high temperature. Possible effects of dietary supplementation with 200 or 400 mg/kg feed of lemon peel extract (LPE), orange peel extract (OPE) and Curcuma xanthorrhiza essential oil (CXEO) under hot conditions (34 °C with 50% relative humidity for 5 h daily starting from day 28 until day 38 of age) on blood antioxidant enzyme activities, biochemical parameters and antibody titres of broiler chickens were investigated. All extracts are rich in phenolic compounds and highly available. Compared to control, supplementation with OPE at 400 mg/kg and CXEO significantly increased erythrocyte glutathione peroxidase and superoxide dismutase activity, plasma growth hormone concentrations and serum phosphorus, total protein and chloride concentrations and decreased serum low-density lipoprotein and cholesterol concentrations in chickens at 38 days of age. Regarding antibody titres, CXEO supplementation at 400 mg/kg caused a significant increase in bronchitis antibody titres. Supplementation with LPE and OPE gave more inconsistent results. Most interesting, 400 mg/kg LPE significantly increased 3,5,3'-triiodothyronine and GH concentration as compared to the control. In conclusion, the herbal extracts tested in this study, in particular CXEO at 400 mg/kg, may relieve some of the changes in blood composition induced by increased ambient temperatures. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

Data book for 12.5-inch diameter SRB thermal model water flotation test: 14.7 psia, series P020

NASA Technical Reports Server (NTRS)

Allums, S. L.

1974-01-01

Data acquired from the initial series of tests conducted to determine how thermal conditions affect SRB (Space Shuttle Solid Rocket Booster) flotation are presented. Acceleration, pressure, and temperature data recorded from initial water impact to final flotation position using a 12.5-inch diameter thermal model of the SRB at ambient pressure are included. The model was 136.9 inches long and weighed 117.3 lbm. The tests indicated the following differences from ambient temperature tests: (1) significant negative static pressures can occur during penetration; (2) maximum penetration is increased; and (3) final flotation is in the spar buoy mode.

Ambient intelligence application based on environmental measurements performed with an assistant mobile robot.

PubMed

Martinez, Dani; Teixidó, Mercè; Font, Davinia; Moreno, Javier; Tresanchez, Marcel; Marco, Santiago; Palacín, Jordi

2014-03-27

This paper proposes the use of an autonomous assistant mobile robot in order to monitor the environmental conditions of a large indoor area and develop an ambient intelligence application. The mobile robot uses single high performance embedded sensors in order to collect and geo-reference environmental information such as ambient temperature, air velocity and orientation and gas concentration. The data collected with the assistant mobile robot is analyzed in order to detect unusual measurements or discrepancies and develop focused corrective ambient actions. This paper shows an example of the measurements performed in a research facility which have enabled the detection and location of an uncomfortable temperature profile inside an office of the research facility. The ambient intelligent application has been developed by performing some localized ambient measurements that have been analyzed in order to propose some ambient actuations to correct the uncomfortable temperature profile.

Ambient Intelligence Application Based on Environmental Measurements Performed with an Assistant Mobile Robot

PubMed Central

Martinez, Dani; Teixidó, Mercè; Font, Davinia; Moreno, Javier; Tresanchez, Marcel; Marco, Santiago; Palacín, Jordi

2014-01-01

This paper proposes the use of an autonomous assistant mobile robot in order to monitor the environmental conditions of a large indoor area and develop an ambient intelligence application. The mobile robot uses single high performance embedded sensors in order to collect and geo-reference environmental information such as ambient temperature, air velocity and orientation and gas concentration. The data collected with the assistant mobile robot is analyzed in order to detect unusual measurements or discrepancies and develop focused corrective ambient actions. This paper shows an example of the measurements performed in a research facility which have enabled the detection and location of an uncomfortable temperature profile inside an office of the research facility. The ambient intelligent application has been developed by performing some localized ambient measurements that have been analyzed in order to propose some ambient actuations to correct the uncomfortable temperature profile. PMID:24681671

Recovery behaviour of shape memory polyurethane based laminates after thermoforming

NASA Astrophysics Data System (ADS)

Wu, Shuiliang; Xu, Wensen; Prasath Balamurugan, G.; Thompson, Michael R.; Nielsen, Kent E.; Brandys, Frank A.

2017-11-01

Shape memory polymers (SMPs) can be used to produce a new class of decorative films capable of improved formability and shape recovery in polymer laminates, which are increasingly being used for automotive, aerospace, construction and commercial applications. As a relatively new field there is little knowledge on the shape recovery behaviour of laminates with a SMP film and few methods of quantify that behaviour. The influences of different variables that affect the recovery behaviour of thermoplastic shape memory polyurethanes based laminates including ambient temperature (45 °C and 65 °C), material modulus, and adhesive strength were investigated after thermoforming, through both experimental and modelling methods. The empirical model assisted in identifying the contributions of the adhesive to transfer stresses, which dampened the recovery of the laminate with lower shear strength adhesives. Increasing ambient temperature and the film modulus increased both the final angle recovery ratios and recovery rates.

Indoor Temperatures in Patient Waiting Rooms in Eight Rural Primary Health Care Centers in Northern South Africa and the Related Potential Risks to Human Health and Wellbeing

PubMed Central

Wright, Caradee Y.; Street, Renée A.; Cele, Nokulunga; Kunene, Zamantimande; Balakrishna, Yusentha; Albers, Patricia N.; Mathee, Angela

2017-01-01

Increased temperatures affect human health and vulnerable groups including infants, children, the elderly and people with pre-existing diseases. In the southern African region climate models predict increases in ambient temperature twice that of the global average temperature increase. Poor ventilation and lack of air conditioning in primary health care clinics, where duration of waiting time may be as long as several hours, pose a possible threat to patients seeking primary health care. Drawing on information measured by temperature loggers installed in eight clinics in Giyani, Limpopo Province of South Africa, we were able to determine indoor temperatures of waiting rooms in eight rural primary health care facilities. Mean monthly temperature measurements inside the clinics were warmer during the summer months of December, January and February, and cooler during the autumn months of March, April and May. The highest mean monthly temperature of 31.4 ± 2.7 °C was recorded in one clinic during February 2016. Maximum daily indoor clinic temperatures exceeded 38 °C in some clinics. Indoor temperatures were compared to ambient (outdoor) temperatures and the mean difference between the two showed clinic waiting room temperatures were higher by 2–4 °C on average. Apparent temperature (AT) incorporating relative humidity readings made in the clinics showed ‘realfeel’ temperatures were >4 °C higher than measured indoor temperature, suggesting a feeling of ‘stuffiness’ and discomfort may have been experienced in the waiting room areas. During typical clinic operational hours of 8h00 to 16h00, mean ATs fell into temperature ranges associated with heat–health impact warning categories of ‘caution’ and ‘extreme caution’. PMID:28067816

Indoor Temperatures in Patient Waiting Rooms in Eight Rural Primary Health Care Centers in Northern South Africa and the Related Potential Risks to Human Health and Wellbeing.

PubMed

Wright, Caradee Y; Street, Renée A; Cele, Nokulunga; Kunene, Zamantimande; Balakrishna, Yusentha; Albers, Patricia N; Mathee, Angela

2017-01-06

Increased temperatures affect human health and vulnerable groups including infants, children, the elderly and people with pre-existing diseases. In the southern African region climate models predict increases in ambient temperature twice that of the global average temperature increase. Poor ventilation and lack of air conditioning in primary health care clinics, where duration of waiting time may be as long as several hours, pose a possible threat to patients seeking primary health care. Drawing on information measured by temperature loggers installed in eight clinics in Giyani, Limpopo Province of South Africa, we were able to determine indoor temperatures of waiting rooms in eight rural primary health care facilities. Mean monthly temperature measurements inside the clinics were warmer during the summer months of December, January and February, and cooler during the autumn months of March, April and May. The highest mean monthly temperature of 31.4 ± 2.7 °C was recorded in one clinic during February 2016. Maximum daily indoor clinic temperatures exceeded 38 °C in some clinics. Indoor temperatures were compared to ambient (outdoor) temperatures and the mean difference between the two showed clinic waiting room temperatures were higher by 2-4 °C on average. Apparent temperature (AT) incorporating relative humidity readings made in the clinics showed 'realfeel' temperatures were >4 °C higher than measured indoor temperature, suggesting a feeling of 'stuffiness' and discomfort may have been experienced in the waiting room areas. During typical clinic operational hours of 8h00 to 16h00, mean ATs fell into temperature ranges associated with heat-health impact warning categories of 'caution' and 'extreme caution'.

Trailer microclimate during commercial transportation of feeder cattle and relationship to indicators of cattle welfare.

PubMed

Goldhawk, C; Crowe, T; Janzen, E; González, L A; Kastelic, J; Pajor, E; Schwartzkopf-Genswein, K S

2014-11-01

Nineteen loads of commercial feeder cattle (BW 376 ± 39 kg, mean ± SD) transported for 18 ± 4.5 h in summer and winter seasons were used to collect data on internal temperature and humidity conditions in the deck and belly compartment of pot-bellied trailers and their relationship with shrink, cortisol, and morbidity. Measurements of temperature or humidity at ceiling or animal level did not vary with transportation factors. Temperature and humidity ratio was greater at animal-level than ambient conditions during nonhighway travel and stationary periods (P < 0.01). During the 3 time periods evaluated within journeys, there was a larger difference between animal-level and ambient conditions during the winter than during the summer (P < 0.01); however, this difference was not associated with other transport factors (P > 0.05). Evening loads (1700 and 2100 h) experienced more shrink in the summer than in the winter (11.2 ± 0.5 vs. 9.0 ± 0.5% of BW; P = 0.03). A 1°C increase in difference between average animal-level temperature in transit and the mean ambient temperature during the 10 d before transport was associated with a 0.11 ± 0.03% of BW increase in shrink (P < 0.01) and 0.006 ± 0.002 ng/mL increase in posttransport cortisol concentration (P = 0.05). Animal-level temperature-humidity index (THI) events (consecutive observations of THI greater than 78°F) were more likely to last for longer than 1 h when the trailer was stationary vs. traveling (mean = 1.8, confidence level 95% = 1.33, 2.52). During THI events at animal level, the disagreement with ambient temperature regarding THI classification was lower when the vehicle was traveling vs. stationary (95.5 ± 0.01% vs. 99.7 ± 0.002% of THI event in disagreement; P < 0.01) and was greatest in events less than 1 h (99.8 ± 0.0% vs. 91.7 ± 0.03% of THI event in disagreement; P < 0.01). The average magnitude of the difference during these events was 11.4 ± 7.6°F and was not affected by transportation factors (P > 0.05). Despite association between indicators of calf welfare and microclimate, all cattle arrived in good condition and there was 0.96% treatment rate within the first 30 d after arrival. Management and auditing decisions related to transportation of feeder cattle should consider the relationship between animal-level and ambient conditions and conditions before transportation. Under the commercial conditions of the current study, the transportation process did not appear to cause distress according to the dimensions of animal welfare that were assessed.

Investigation of Water Dissociation and Surface Hydroxyl Stability on Pure and Ni-Modified CoOOH by Ambient Pressure Photoelectron Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Zhu; Kronawitter, Coleman X.; Waluyo, Iradwikanari

Water adsorption and reaction on pure and Ni-modified CoOOH nanowires were investigated using ambient pressure photoemission spectroscopy (APPES). The unique capabilities of APPES enable us to observe water dissociation and monitor formation of surface species on pure and Ni-modified CoOOH under elevated pressures and temperatures for the first time. Over a large range of pressures (UHV to 1 Torr), water dissociates readily on the pure and Ni-modified CoOOH surfaces at 27 °C. With an increase in H 2O pressure, a greater degree of surface hydroxylation was observed for all samples. At 1 Torr H 2O, ratios of different oxygen speciesmore » indicate a transformation of CoOOH to CoO xH y in pure and Ni-modified CoOOH. In temperature dependent studies, desorption of weakly bound water and surface dehydroxylation were observed with increasing temperature. In conclusion, larger percentages of surface hydroxyl groups at higher temperatures were observed on Ni-modified CoOOH compared to pure CoOOH, which indicates an increased stability of surface hydroxyl groups on these Ni-modified surfaces.« less

Investigation of Water Dissociation and Surface Hydroxyl Stability on Pure and Ni-Modified CoOOH by Ambient Pressure Photoelectron Spectroscopy

DOE PAGES

Chen, Zhu; Kronawitter, Coleman X.; Waluyo, Iradwikanari; ...

2017-09-07

Water adsorption and reaction on pure and Ni-modified CoOOH nanowires were investigated using ambient pressure photoemission spectroscopy (APPES). The unique capabilities of APPES enable us to observe water dissociation and monitor formation of surface species on pure and Ni-modified CoOOH under elevated pressures and temperatures for the first time. Over a large range of pressures (UHV to 1 Torr), water dissociates readily on the pure and Ni-modified CoOOH surfaces at 27 °C. With an increase in H 2O pressure, a greater degree of surface hydroxylation was observed for all samples. At 1 Torr H 2O, ratios of different oxygen speciesmore » indicate a transformation of CoOOH to CoO xH y in pure and Ni-modified CoOOH. In temperature dependent studies, desorption of weakly bound water and surface dehydroxylation were observed with increasing temperature. In conclusion, larger percentages of surface hydroxyl groups at higher temperatures were observed on Ni-modified CoOOH compared to pure CoOOH, which indicates an increased stability of surface hydroxyl groups on these Ni-modified surfaces.« less

Residual Tensile Strength and Bond Properties of GFRP Bars after Exposure to Elevated Temperatures.

PubMed

Ellis, Devon S; Tabatabai, Habib; Nabizadeh, Azam

2018-02-27

The use of fiber reinforced polymer (FRP) bars in reinforced concrete members enhances corrosion resistance when compared to traditional steel reinforcing bars. Although there is ample research available on the behavior of FRP bars and concrete members reinforced with FRP bars under elevated temperatures (due to fire), there is little published information available on their post-fire residual load capacity. This paper reports residual tensile strength, modulus of elasticity, and bond strength (to concrete) of glass fiber reinforced polymer (GFRP) bars after exposure to elevated temperatures of up to 400 °C and subsequent cooling to an ambient temperature. The results showed that the residual strength generally decreases with increasing temperature exposure. However, as much as 83% of the original tensile strength and 27% of the original bond strength was retained after the specimens were heated to 400 °C and then cooled to ambient temperature. The residual bond strength is a critical parameter in post-fire strength assessments of GFRP-reinforced concrete members.

Residual Tensile Strength and Bond Properties of GFRP Bars after Exposure to Elevated Temperatures

PubMed Central

Ellis, Devon S.

2018-01-01

The use of fiber reinforced polymer (FRP) bars in reinforced concrete members enhances corrosion resistance when compared to traditional steel reinforcing bars. Although there is ample research available on the behavior of FRP bars and concrete members reinforced with FRP bars under elevated temperatures (due to fire), there is little published information available on their post-fire residual load capacity. This paper reports residual tensile strength, modulus of elasticity, and bond strength (to concrete) of glass fiber reinforced polymer (GFRP) bars after exposure to elevated temperatures of up to 400 °C and subsequent cooling to an ambient temperature. The results showed that the residual strength generally decreases with increasing temperature exposure. However, as much as 83% of the original tensile strength and 27% of the original bond strength was retained after the specimens were heated to 400 °C and then cooled to ambient temperature. The residual bond strength is a critical parameter in post-fire strength assessments of GFRP-reinforced concrete members. PMID:29495489

Correlation between corneal and ambient temperature with particular focus on polar conditions.

PubMed

Slettedal, Jon Klokk; Ringvold, Amund

2015-08-01

To examine the relationship between human corneal and environmental temperature. An infrared camera was used to measure the corneal surface temperature in a group of healthy volunteers as well as in an experimental setting with donor corneas and an artificial anterior chamber, employing circulating saline at +37°C. Liquid nitrogen was used to obtain a very low temperature in the experimental setting. High ambient temperature measurements were performed in a sauna. In healthy volunteers, the cornea required at least 20-30 min to adapt to change in ambient temperature. The relationship between corneal and external temperature was relatively linear. At the two extremes, +83°C and -40°C, the corneal temperature was +42°C and +25.1°C, respectively. In the experimental setting, corneal temperature was +24.3°C at air temperature -40°C. A rather stable aqueous humour temperature of +37°C and high thermal conductivity of the corneal tissue prevent corneal frostbite even at extremely low ambient temperatures. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Simple roost nests confer large energetic savings for sparrow-weavers.

PubMed

Ferguson, J W H; Nijland, M J M; Bennett, N C

2002-02-01

White-browed sparrow-weavers (Plocepasser mahali, body mass 40 g) are group-living passerines adapted to the semi-arid environment of north-eastern and south-western Africa. During winter, the nocturnal ambient temperature of these regions often falls below 0 degrees C. imposing conditions demanding an increase in thermoregulatory heat production. Individuals roost throughout the year in inverted U-shaped roost nests. We investigated the energetic advantages of roosting by measuring nest and ambient temperatures in the field, as well as the resting metabolic rate (RMR) of the birds. The sparrow-weavers exhibited a wide thermoneutral zone (13 degrees C - 32 degrees C). Although RMR at thermoneutrality (40.2 J g.h(-1)) conforms with those of other passerines. the value at 0 degrees C (74.8 J g.h(-1)) is significantly lower than expected. The slope of the line below the lower critical temperature is unexpectedly steep, however, and appears to cause the physiological requirement for nest roosting due to a high cost of thermoregulation at low temperatures, perhaps due to shivering or non-shivering thermogenesis. The nest temperature at 0 degrees C ambient is 5 degrees C. resulting in a saving of some 7% in the energy spent during winter nights when food resources are in short supply compared with the rest of the year.

FOLIAR NITROGEN CONCENTRATIONS AND NATURAL ABUNDANCE OF 15N SUGGEST NITROGEN ALLOCATION PATTERNS OF DOUGLAS-FIR AND MYCORRHIZAL FUNGI DURING DEVELOPMENT IN ELEVATED CARBON DIOXIDE CONCENTRATION AND TEMPERATURE

EPA Science Inventory

In an experiment using Pseudotsuga menziesii (Mirb.) Franco (Douglas-fir) seedlings and a 2x2 factorial design in enclosed mesocosms, temperatures were maintained at ambient or +3.5 degrees C above ambient, and CO2 levels were maintained at ambient or 179 ppm above ambient. Two ...

Incidence and seasonality of hypothermia among newborns in southern Nepal.

PubMed

Mullany, Luke C; Katz, Joanne; Khatry, Subarna K; Leclerq, Steven C; Darmstadt, Gary L; Tielsch, James M

2010-01-01

To quantify incidence, age distribution, and seasonality of neonatal hypothermia among a large population cohort. Longitudinal cohort study. Sarlahi, Nepal. A total of 23 240 newborns born between September 2, 2002, and February 1, 2006. Main Exposures Community-based workers recorded axillary temperature on days 1 through 4, 6, 8, 10, 12, 14, 21, and 28 (213 636 total measurements). Regression smoothing was used to describe axillary temperature patterns during the newborn period. Hypothermia incidence in the first day, week, and month were estimated using standard cutoffs. Ambient temperatures allowed comparison of mild hypothermia (36.0 degrees C to <36.5 degrees C) and moderate or severe hypothermia (<36.0 degrees C) incidence over mean ambient temperature quintiles. Measurements lower than 36.5 degrees C were observed in 21 459 babies (92.3%); half (48.6%) had moderate or severe hypothermia, and risk peaked in the first 24 to 72 hours of life. Risk of moderate or severe hypothermia increased by 41.3% (95% confidence interval, 40.0%-42.7%) for every 5 degrees C decrease in average ambient temperature. Relative to the highest quintile, risk was 4.03 (95% confidence interval, 3.77-4.30) times higher among babies exposed to the lowest quintile of average ambient temperature. In the hot season, one-fifth of the babies (18.2%) were observed below the moderate hypothermia cutoff. Mild or moderate hypothermia was nearly universal, with substantially higher risk in the cold season. However, incidence in the hot season was also high; thus, year-round thermal care promotion is required. Research on community, household, and caretaker practices associated with hypothermia can guide behavioral interventions to reduce risk.

Changes in ambient temperature differentially alter the thermoregulatory, cardiac and locomotor stimulant effects of 4-methylmethcathinone (mephedrone).

PubMed

Miller, M L; Creehan, K M; Angrish, D; Barlow, D J; Houseknecht, K L; Dickerson, T J; Taffe, M A

2013-01-01

The substituted cathinone compound known as mephedrone (4-methylmethcathinone; 4-MMC) has become popular with recreational users of psychomotor-stimulant compounds. Only recently have the first preclinical studies provided information about this drug in the scientific literature; nevertheless, media reports have led to drug control actions in the UK and across several US states. Rodent studies indicate that 4-MMC exhibits neuropharmacological similarity to 3,4-methylenedioxymethamphetamine (MDMA) and prompt investigation of the thermoregulatory, cardiac and locomotor effects of 4-MMC. This study focuses on the role of ambient temperature, which has been shown to shift the effects of MDMA from hyperthermic to hypothermic. Male Sprague-Dawley rats were monitored after subcutaneous administration of 4-MMC (1.0-5.6 mg/kg) using an implantable radiotelemetry system under conditions of low (20 °C) and high (30 °C) ambient temperature. A pharmacokinetic study found a T(max) of 0.25 h and a C(max) of 1206 ng/ml after 5.6 mg/kg 4-MMC. A dose-dependent reduction of body temperature was produced by 4-MMC at 20 °C but there was no temperature change at 30 °C. Increased locomotor activity was observed after 4-MMC administration under both ambient temperatures, however, significantly more activity was observed at 30 °C. Heart rate was slowed by 1.0 and 5.6 mg/kg 4-MMC at 20°C, and was slower in the 30 °C vs. 20 °C condition across all treatments. These results show that the cathinone analog 4-MMC exhibits in vivo thermoregulatory properties that are distinct from those produced by MDMA. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Stereoselective Effects of Abused “Bath Salt” Constituent 3,4-Methylenedioxypyrovalerone in Mice: Drug Discrimination, Locomotor Activity, and Thermoregulation

PubMed Central

Gannon, Brenda M.; Williamson, Adrian; Suzuki, Masaki; Rice, Kenner C.

2016-01-01

3,4-Methylenedioxypyrovalerone (MDPV) is a common constituent of illicit “bath salts” products. MDPV is a chiral molecule, but the contribution of each enantiomer to in vivo effects in mice has not been determined. To address this, mice were trained to discriminate 10 mg/kg cocaine from saline, and substitutions with racemic MDPV, S(+)-MDPV, and R(−)-MDPV were performed. Other mice were implanted with telemetry probes to monitor core temperature and locomotor responses elicited by racemic MDPV, S(+)-MDPV, and R(−)-MDPV under a warm (28°C) or cool (20°C) ambient temperature. Mice reliably discriminated the cocaine training dose from saline, and each form of MDPV fully substituted for cocaine, although marked potency differences were observed such that S(+)-MDPV was most potent, racemic MDPV was less potent than the S(+) enantiomer, and R(−)-MDPV was least potent. At both ambient temperatures, locomotor stimulant effects were observed after doses of S(+)-MDPV and racemic MDPV, but R(−)-MDPV did not elicit locomotor stimulant effects at any tested dose. Interestingly, significant increases in maximum core body temperature were only observed after administration of racemic MDPV in the warm ambient environment; neither MDPV enantiomer altered core temperature at any dose tested, at either ambient temperature. These studies suggest that all three forms of MDPV induce biologic effects, but R(−)-MDPV is less potent than S(+)-MDPV and racemic MDPV. Taken together, these data suggest that the S(+)-MDPV enantiomer is likely responsible for the majority of the biologic effects of the racemate and should be targeted in therapeutic efforts against MDPV overdose and abuse. PMID:26769917

Stereoselective Effects of Abused "Bath Salt" Constituent 3,4-Methylenedioxypyrovalerone in Mice: Drug Discrimination, Locomotor Activity, and Thermoregulation.

PubMed

Gannon, Brenda M; Williamson, Adrian; Suzuki, Masaki; Rice, Kenner C; Fantegrossi, William E

2016-03-01

3,4-Methylenedioxypyrovalerone (MDPV) is a common constituent of illicit "bath salts" products. MDPV is a chiral molecule, but the contribution of each enantiomer to in vivo effects in mice has not been determined. To address this, mice were trained to discriminate 10 mg/kg cocaine from saline, and substitutions with racemic MDPV, S(+)-MDPV, and R(-)-MDPV were performed. Other mice were implanted with telemetry probes to monitor core temperature and locomotor responses elicited by racemic MDPV, S(+)-MDPV, and R(-)-MDPV under a warm (28°C) or cool (20°C) ambient temperature. Mice reliably discriminated the cocaine training dose from saline, and each form of MDPV fully substituted for cocaine, although marked potency differences were observed such that S(+)-MDPV was most potent, racemic MDPV was less potent than the S(+) enantiomer, and R(-)-MDPV was least potent. At both ambient temperatures, locomotor stimulant effects were observed after doses of S(+)-MDPV and racemic MDPV, but R(-)-MDPV did not elicit locomotor stimulant effects at any tested dose. Interestingly, significant increases in maximum core body temperature were only observed after administration of racemic MDPV in the warm ambient environment; neither MDPV enantiomer altered core temperature at any dose tested, at either ambient temperature. These studies suggest that all three forms of MDPV induce biologic effects, but R(-)-MDPV is less potent than S(+)-MDPV and racemic MDPV. Taken together, these data suggest that the S(+)-MDPV enantiomer is likely responsible for the majority of the biologic effects of the racemate and should be targeted in therapeutic efforts against MDPV overdose and abuse. U.S. Government work not protected by U.S. copyright.

Oxidative damage and brain concentrations of free amino acid in chicks exposed to high ambient temperature.

PubMed

Chowdhury, Vishwajit S; Tomonaga, Shozo; Ikegami, Taro; Erwan, Edi; Ito, Kentaro; Cockrem, John F; Furuse, Mitsuhiro

2014-03-01

High ambient temperatures (HT) reduce food intake and body weight in young chickens, and HT can cause increased expression of hypothalamic neuropeptides. The mechanisms by which HT act, and the effects of HT on cellular homeostasis in the brain, are however not well understood. In the current study lipid peroxidation and amino acid metabolism were measured in the brains of 14 d old chicks exposed to HT (35 °C for 24- or 48-h) or to control thermoneutral temperature (CT; 30 °C). Malondialdehyde (MDA) was measured in the brain to determine the degree of oxidative damage. HT increased body temperature and reduced food intake and body weight gain. HT also increased diencephalic oxidative damage after 48 h, and altered some free amino acid concentrations in the diencephalon. Diencephalic MDA concentrations were increased by HT and time, with the effect of HT more prominent with increasing time. HT altered cystathionine, serine, tyrosine and isoleucine concentrations. Cystathionine was lower in HT birds compared with CT birds at 24h, whilst serine, tyrosine and isoleucine were higher at 48 h in HT birds. An increase in oxidative damage and alterations in amino acid concentrations in the diencephalon may contribute to the physiological, behavioral and thermoregulatory responses of heat-exposed chicks. Copyright © 2013 Elsevier Inc. All rights reserved.

Influence of humidification on comfort during noninvasive ventilation with a helmet.

PubMed

Ueta, Kazuyoshi; Tomita, Toshiji; Uchiyama, Akinori; Ohta, Noriyuki; Iguchi, Naoya; Goto, Yukiko; Fujino, Yuji

2013-05-01

To evaluate optimal humidifier water temperature when using a helmet for noninvasive ventilation. Twenty-eight healthy individuals underwent 8 cm H2O CPAP ventilation with FIO2 of 0.21 and 0.5. Each was sequentially tested in the following order: using the helmet without humidification at ambient temperature; with humidification with unheated chamber water; and with humidification with the chamber water at 31°C, 34°C, and 37°C. At each setting, after a 20 min stabilization period, measurements were taken. Comfort level at each setting was evaluated using a visual analog scale rated zero (least comfortable) to 10 (most comfortable). Temperature and relative and absolute humidity inside the helmet increased; however, the comfort scores significantly decreased as the humidification chamber water temperature increased. Regardless of the FIO2, statistically significantly highest comfort scores were obtained when humidification water, with and without active humidification, was at ambient temperature. Unacceptable absolute humidity was obtained only without humidification at room temperature when FIO2 was 0.5. With the clinical use of a helmet, for patient comfort and mucosal humidification during CPAP, the most desirable conditions are likely to be obtained by humidifying without heating, that is by leaving the water in the humidifier chamber at room temperature.

[Role of oxotremorine in arginine vasopressin-induced hypothermia and its effects on behavioral thermoregulatory response in rats].

PubMed

Shen, Zi-Ling; Yang, Yong-Lu; Sun, Bing; Tang, Yu; Wang, Nian

2012-03-01

To investigate the role of oxotremorine in arginine vasopressin (AVP)-induced hypothermia and its effects on the behavioral thermoregulatory response. Core temperature (Tc), brown adipose tissue (BAT) temperature and motor activities were monitored in undisturbed female SD rats using radiotelemetry. The behavioral thermoregulatory response was monitored in rats using radiotelemetric temperature gradient apparatus. Effect of AVP (10 microg/kg) and oxotremorine (0.25 mg/kg) on Tc, motor activities, BAT temperature (T(BAT)), grooming activities and the behavioral thermoregulatory response were observed in rats. Administration of AVP and oxotremorine caused a significant drop in Tc, T(BAT), and an increases in grooming activities, respectively. The hypothermic responses were accompanied with a preference for cooler ambient temperature. Oxotremorine augmented the reduction of Tc, T(BAT), and the elevation of grooming activities resulting from AVP, and lasting a longer time. Administration of oxotremorine followed immediately by AVP injection in rats was also shown to induce a preference for cooler ambient temperature, but there was no significant difference compared with AVP. AVP-induced hypothermia was related with the set point temperature reduction, inhibiton of BAT thermogenesis and an increases in grooming activities. Oxotremorine could participate in peripheral AVP-induced hypothermia by affecting BAT thermogenesis and behavioral thermoregulation.

Radioprotection in depressed metabolic states: The physiology of helium-cold hypothermia

NASA Technical Reports Server (NTRS)

Musacchia, X. J.

1973-01-01

The use of hypothermia as a means of radiation protection was studied on a variety of mammals exposed to 80% helium-20% oxygen atmospheres at low ambient temperatures. Results show that the LD for normothermic animals significantly increased compared with hypothermic animals; similar results were obtained for hibernating mammalians. Pre-exposure of animals to cold temperatures increased their ability to withstand radiation levels close to LD sub 50.

Splicing-related genes are alternatively spliced upon changes in ambient temperatures in plants

PubMed Central

Bucher, Johan; Lammers, Michiel; Busscher-Lange, Jacqueline; Bonnema, Guusje; Rodenburg, Nicole; Proveniers, Marcel C. G.; Angenent, Gerco C.

2017-01-01

Plants adjust their development and architecture to small variations in ambient temperature. In a time in which temperatures are rising world-wide, the mechanism by which plants are able to sense temperature fluctuations and adapt to it, is becoming of special interest. By performing RNA-sequencing on two Arabidopsis accession and one Brassica species exposed to temperature alterations, we showed that alternative splicing is an important mechanism in ambient temperature sensing and adaptation. We found that amongst the differentially alternatively spliced genes, splicing related genes are enriched, suggesting that the splicing machinery itself is targeted for alternative splicing when temperature changes. Moreover, we showed that many different components of the splicing machinery are targeted for ambient temperature regulated alternative splicing. Mutant analysis of a splicing related gene that was differentially spliced in two of the genotypes showed an altered flowering time response to different temperatures. We propose a two-step mechanism where temperature directly influences alternative splicing of the splicing machinery genes, followed by a second step where the altered splicing machinery affects splicing of downstream genes involved in the adaptation to altered temperatures. PMID:28257507

Towards eliminating systematic errors caused by the experimental conditions in Biochemical Methane Potential (BMP) tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strömberg, Sten, E-mail: sten.stromberg@biotek.lu.se; Nistor, Mihaela, E-mail: mn@bioprocesscontrol.com; Liu, Jing, E-mail: jing.liu@biotek.lu.se

Highlights: • The evaluated factors introduce significant systematic errors (10–38%) in BMP tests. • Ambient temperature (T) has the most substantial impact (∼10%) at low altitude. • Ambient pressure (p) has the most substantial impact (∼68%) at high altitude. • Continuous monitoring of T and p is not necessary for kinetic calculations. - Abstract: The Biochemical Methane Potential (BMP) test is increasingly recognised as a tool for selecting and pricing biomass material for production of biogas. However, the results for the same substrate often differ between laboratories and much work to standardise such tests is still needed. In the currentmore » study, the effects from four environmental factors (i.e. ambient temperature and pressure, water vapour content and initial gas composition of the reactor headspace) on the degradation kinetics and the determined methane potential were evaluated with a 2{sup 4} full factorial design. Four substrates, with different biodegradation profiles, were investigated and the ambient temperature was found to be the most significant contributor to errors in the methane potential. Concerning the kinetics of the process, the environmental factors’ impact on the calculated rate constants was negligible. The impact of the environmental factors on the kinetic parameters and methane potential from performing a BMP test at different geographical locations around the world was simulated by adjusting the data according to the ambient temperature and pressure of some chosen model sites. The largest effect on the methane potential was registered from tests performed at high altitudes due to a low ambient pressure. The results from this study illustrate the importance of considering the environmental factors’ influence on volumetric gas measurement in BMP tests. This is essential to achieve trustworthy and standardised results that can be used by researchers and end users from all over the world.« less

Thioesterase Superfamily Member 2/Acyl-CoA Thioesterase 13 (Them2/Acot13) Regulates Adaptive Thermogenesis in Mice*

PubMed Central

Kang, Hye Won; Ozdemir, Cafer; Kawano, Yuki; LeClair, Katherine B.; Vernochet, Cecile; Kahn, C. Ronald; Hagen, Susan J.; Cohen, David E.

2013-01-01

Members of the acyl-CoA thioesterase (Acot) gene family hydrolyze fatty acyl-CoAs, but their biological functions remain incompletely understood. Thioesterase superfamily member 2 (Them2; synonym Acot13) is enriched in oxidative tissues, associated with mitochondria, and relatively specific for long chain fatty acyl-CoA substrates. Using Them2−/− mice, we have demonstrated key roles for Them2 in regulating hepatic glucose and lipid metabolism. However, reduced body weights and decreased adiposity in Them2−/− mice observed despite increased food consumption were not well explained. To explore a role in thermogenesis, mice were exposed to ambient temperatures ranging from thermoneutrality (30 °C) to cold (4 °C). In response to short term (24-h) exposures to decreasing ambient temperatures, Them2−/− mice exhibited increased adaptive responses in physical activity, food consumption, and energy expenditure when compared with Them2+/+ mice. By contrast, genotype-dependent differences were not observed in mice that were equilibrated (96 h) at each ambient temperature. In brown adipose tissue, the absence of Them2 was associated with reduced lipid droplets, alterations in the ultrastructure of mitochondria, and increased expression of thermogenic genes. Indicative of a direct regulatory role for Them2 in heat production, cultured primary brown adipocytes from Them2−/− mice exhibited increased norepinephrine-mediated triglyceride hydrolysis and increased rates of O2 consumption, together with elevated expression of thermogenic genes. At least in part by regulating intracellular fatty acid channeling, Them2 functions in brown adipose tissue to suppress adaptive increases in energy expenditure. PMID:24072708

Global variation in the effects of ambient temperature on mortality: a systematic evaluation

PubMed Central

Guo, Yuming; Gasparrini, Antonio; Armstrong, Ben; Li, Shanshan; Tawatsupa, Benjawan; Tobias, Aurelio; Lavigne, Eric; de Sousa Zanotti Stagliorio Coelho, Micheline; Leone, Michela; Pan, Xiaochuan; Tong, Shilu; Tian, Linwei; Kim, Ho; Hashizume, Masahiro; Honda, Yasushi; Guo, Yue-Liang Leon; Wu, Chang-Fu; Punnasiri, Kornwipa; Yi, Seung-Muk; Michelozzi, Paola; Saldiva, Paulo Hilario Nascimento; Williams, Gail

2014-01-01

Background Studies have examined the effects of temperature on mortality in a single city, country or region. However, less evidence is available on the variation in the associations between temperature and mortality in multiple countries, analyzed simultaneously. Methods We obtained daily data on temperature and mortality in 306 communities from 12 countries/regions (Australia, Brazil, Thailand, China, Taiwan, Korea, Japan, Italy, Spain, United Kingdom, United States and Canada). Two-stage analyses were used to assess the non-linear and delayed relationship between temperature and mortality. In the first stage, a Poisson regression allowing over-dispersion with distributed lag non-linear model was used to estimate the community-specific temperature-mortality relationship. In the second stage, a multivariate meta-analysis was used to pool the non-linear and delayed effects of ambient temperature at the national level, in each country. Results The temperatures associated with the lowest mortality were around the 75th percentile of temperature in all the countries/regions, ranging from 66th (Taiwan) to 80th (UK) percentiles. The estimated effects of cold and hot temperatures on mortality varied by community and country. Meta-analysis results show that both cold and hot temperatures increased the risk of mortality in all the countries/regions. Cold effects were delayed and lasted for many days, while hot effects appeared quickly and did not last long. Conclusions People have some ability to adapt to their local climate type, but both cold and hot temperatures are still associated with the risk of mortality. Public health strategies to alleviate the impact of ambient temperatures are important, in particular in the context of climate change. PMID:25166878

Influence of temperature on the single-stage ATAD process predicted by a thermal equilibrium model.

PubMed

Cheng, Jiehong; Zhu, Jun; Kong, Feng; Zhang, Chunyong

2015-06-01

Autothermal thermophilic aerobic digestion (ATAD) is a promising biological process that will produce an effluent satisfying the Class A requirements on pathogen control and land application. The thermophilic temperature in an ATAD reactor is one of the critical factors that can affect the satisfactory operation of the ATAD process. This paper established a thermal equilibrium model to predict the effect of variables on the auto-rising temperature in an ATAD system. The reactors with volumes smaller than 10 m(3) could not achieve temperatures higher than 45 °C under ambient temperature of -5 °C. The results showed that for small reactors, the reactor volume played a key role in promoting auto-rising temperature in the winter. Thermophilic temperature achieved in small ATAD reactors did not entirely depend on the heat release from biological activities during degrading organic matters in sludges, but was related to the ambient temperature. The ratios of surface area-to-effective volume less than 2.0 had less impact on the auto-rising temperature of an ATAD reactor. The influence of ambient temperature on the auto-rising reactor temperature decreased with increasing reactor volumes. High oxygen transfer efficiency had a significant influence on the internal temperature rise in an ATAD system, indicating that improving the oxygen transfer efficiency of aeration devices was a key factor to achieve a higher removal rate of volatile solids (VS) during the ATAD process operation. Compared with aeration using cold air, hot air demonstrated a significant effect on maintaining the internal temperature (usually 4-5 °C higher). Copyright © 2015 Elsevier Ltd. All rights reserved.

Quality Control for Ambient Sampling of PCDD/PCDF from Open Combustion Sources

EPA Science Inventory

Both long duration (> 6 h) and high temperature (up to 139o C) sampling efforts were conducted using ambient air sampling methods to determine if either high volume throughput or higher than ambient sampling temperatures resulted in loss of target polychlorinated dibenzodioxins/d...

Effects of Core-Shell Rubber (CSR) Nanoparticles on the Cryogenic Fracture Toughness of CSR Modified Epoxy

NASA Technical Reports Server (NTRS)

Wang, Jun; Magee, Daniel; Schneider, Judy; Cannon, Seth

2009-01-01

This study investigated the effects of core-shell rubber (CSR) nanoparticles on the mechanical properties and fracture toughness of an epoxy resin at ambient and liquid nitrogen (LN2) temperatures. Varying amounts of Kane Ace(Registered TradeMark) MX130 and Kane Ace(Registered TradeMark) MX960 toughening agent were added to a commercially available EPON 862/Epikure W epoxy resin. Elastic modulus was calculated using quasi-static tensile data. Fracture toughness was evaluated by the resulting breaking energy measured in Charpy impact tests conducted on an instrumented drop tower. The size and distribution of the CSR nanoparticles were characterized using Transmission Electron Microscopy (TEM) and Small Angle X-ray Scattering (SAXS). Scanning Electron Microscopy (SEM) was used to study the fracture surface morphology. The addition of the CSR nanoparticles increased the breaking energy with negligible change in elastic modulus and ultimate tensile stress (UTS). At ambient temperature the breaking energy increased with increasing additions of the CSR nanoparticles up to 13.8wt%, while at LN2 temperatures, it reached a plateau at much lower CSR concentration.

Effect of daily fluctuations in ambient temperature on reproductive failure traits of Landrace and Yorkshire sows under Thai tropical environmental conditions.

PubMed

Jaichansukkit, Teerapong; Suwanasopee, Thanathip; Koonawootrittriron, Skorn; Tummaruk, Padet; Elzo, Mauricio A

2017-03-01

The aim of this study was to determine the effects of daily ranges and maximum ambient temperatures, and other risk factors on reproductive failure of Landrace (L) and Yorkshire (Y) sows under an open-house system in Thailand. Daily ambient temperatures were added to information on 35,579 litters from 5929 L sows and 1057 Y sows from three commercial herds. The average daily temperature ranges (ADT) and the average daily maximum temperatures (PEAK) in three gestation periods from the 35th day of gestation to parturition were classified. The considered reproductive failure traits were the occurrences of mummified fetuses (MM), stillborn piglets (STB), and piglet death losses (PDL) and an indicator trait for number of piglets born alive below the population mean (LBA). A multiple logistic regression model included farrowing herd-year-season (HYS), breed group of sow (BG), parity group (PAR), number of total piglets born (NTB), ADT1, ADT2, ADT3, PEAK1, PEAK2, and PEAK3 as fixed effects, while random effects were animal, repeated observations, and residual. Yorkshire sows had a higher occurrence of LBA than L sows (P = 0.01). The second to fifth parities sows had lower reproductive failures than other parities. The NTB regression coefficients of log-odds were positive (P < 0.01) for all traits. Narrower ranges of ADT3 increased the occurrence of MM, STB, and PDL (P < 0.01), while higher PEAK3 increased the occurrence of MM, STB, PDL, and LBA (P < 0.001). To reduce the risk of reproductive failures, particularly late in gestation, producers would need to closely monitor their temperature management strategies.

Revealing the association between cerebrovascular accidents and ambient temperature: a meta-analysis

NASA Astrophysics Data System (ADS)

Zorrilla-Vaca, Andrés; Healy, Ryan Jacob; Silva-Medina, Melissa M.

2017-05-01

The association between cerebrovascular accidents (CVA) and weather has been described across several studies showing multiple conflicting results. In this paper, we aim to conduct a meta-analysis to further clarify this association, as well as to find the potential sources of heterogeneity. PubMed, EMBASE, and Google Scholar were searched from inception through 2015, for articles analyzing the correlation between the incidence of CVA and temperature. A pooled effect size (ES) was estimated using random effects model and expressed as absolute values. Subgroup analyses by type of CVA were also performed. Heterogeneity and influence of covariates—including geographic latitude of the study site, male percentage, average temperature, and time interval—were assessed by meta-regression analysis. Twenty-six articles underwent full data extraction and scoring. A total of 19,736 subjects with CVA from 12 different countries were included and grouped as ischemic strokes (IS; n = 14,199), intracerebral hemorrhages (ICH; n = 3798), and subarachnoid hemorrhages (SAH; n = 1739). Lower ambient temperature was significantly associated with increase in incidence of overall CVA when using unadjusted (pooled ES = 0.23, P < 0.001) and adjusted data (pooled ES = 0.03, P = 0.003). Subgroup analyses showed that lower temperature has higher impact on the incidence of ICH (pooled ES = 0.34, P < 0.001), than that of IS (pooled ES = 0.22, P < 0.001) and SAH (pooled ES = 0.11, P = 0.012). In meta-regression analysis, the geographic latitude of the study site was the most influencing factor on this association ( Z-score = 8.68). Synthesis of the existing data provides evidence supporting that a lower ambient temperature increases the incidence of CVA. Further population-based studies conducted at negative latitudes are needed to clarify the influence of this factor.

Method for controlling exhaust gas heat recovery systems in vehicles

DOEpatents

Spohn, Brian L.; Claypole, George M.; Starr, Richard D

2013-06-11

A method of operating a vehicle including an engine, a transmission, an exhaust gas heat recovery (EGHR) heat exchanger, and an oil-to-water heat exchanger providing selective heat-exchange communication between the engine and transmission. The method includes controlling a two-way valve, which is configured to be set to one of an engine position and a transmission position. The engine position allows heat-exchange communication between the EGHR heat exchanger and the engine, but does not allow heat-exchange communication between the EGHR heat exchanger and the oil-to-water heat exchanger. The transmission position allows heat-exchange communication between the EGHR heat exchanger, the oil-to-water heat exchanger, and the engine. The method also includes monitoring an ambient air temperature and comparing the monitored ambient air temperature to a predetermined cold ambient temperature. If the monitored ambient air temperature is greater than the predetermined cold ambient temperature, the two-way valve is set to the transmission position.

The effect of acclimatization and ambient temperature on heat withdrawal threshold in rats.

PubMed

Vítková, J; Loučka, M; Boček, J; Vaculín, S

2015-01-01

Nociception in rats is frequently measured in terms of latency of withdrawal reaction to radiant heat (thermal nociceptive threshold). The aim of this study was to determine how much housing acclimatization and ambient temperature affect the results of thermal pain threshold testing. All experiments used adult male Wistar rats. Thermal pain thresholds were tested using the radiant heat withdrawal reaction at three different body sites: forepaws, hind paws and tail. Skin temperature was measured using an Infrared thermometer and ambient temperature was set at 18, 20, 24 or 26 °C. The results demonstrate that (1) thermal pain threshold was inversely related to both ambient and skin temperature; (2) housing acclimatization and repeated testing had no effect on nociceptive thresholds at any of the three body sites; (3) a resting, cranio-caudal distribution, of nociceptive sensitivity was observed; (4) hind paws and tail were more sensitive to changes of skin and ambient temperature than forepaws. These findings show the importance of recording laboratory conditions in experiments and their influence on results. © 2014 European Pain Federation - EFIC®

33 CFR 159.119 - Operability test; temperature range.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Operability test; temperature... Operability test; temperature range. The device must operate in an ambient temperature of 5 °C with inlet operating fluid temperature varying from 2 °C to 32 °C and in an ambient temperature of 50 °C with inlet...

33 CFR 159.119 - Operability test; temperature range.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Operability test; temperature... Operability test; temperature range. The device must operate in an ambient temperature of 5 °C with inlet operating fluid temperature varying from 2 °C to 32 °C and in an ambient temperature of 50 °C with inlet...

33 CFR 159.119 - Operability test; temperature range.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Operability test; temperature... Operability test; temperature range. The device must operate in an ambient temperature of 5 °C with inlet operating fluid temperature varying from 2 °C to 32 °C and in an ambient temperature of 50 °C with inlet...

33 CFR 159.119 - Operability test; temperature range.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Operability test; temperature... Operability test; temperature range. The device must operate in an ambient temperature of 5 °C with inlet operating fluid temperature varying from 2 °C to 32 °C and in an ambient temperature of 50 °C with inlet...

The Short-Term Effect of Ambient Temperature on Mortality in Wuhan, China: A Time-Series Study Using a Distributed Lag Non-Linear Model

PubMed Central

Zhang, Yunquan; Li, Cunlu; Feng, Renjie; Zhu, Yaohui; Wu, Kai; Tan, Xiaodong; Ma, Lu

2016-01-01

Less evidence concerning the association between ambient temperature and mortality is available in developing countries/regions, especially inland areas of China, and few previous studies have compared the predictive ability of different temperature indictors (minimum, mean, and maximum temperature) on mortality. We assessed the effects of temperature on daily mortality from 2003 to 2010 in Jiang’an District of Wuhan, the largest city in central China. Quasi-Poisson generalized linear models combined with both non-threshold and double-threshold distributed lag non-linear models (DLNM) were used to examine the associations between different temperature indictors and cause-specific mortality. We found a U-shaped relationship between temperature and mortality in Wuhan. Double-threshold DLNM with mean temperature performed best in predicting temperature-mortality relationship. Cold effect was delayed, whereas hot effect was acute, both of which lasted for several days. For cold effects over lag 0–21 days, a 1 °C decrease in mean temperature below the cold thresholds was associated with a 2.39% (95% CI: 1.71, 3.08) increase in non-accidental mortality, 3.65% (95% CI: 2.62, 4.69) increase in cardiovascular mortality, 3.87% (95% CI: 1.57, 6.22) increase in respiratory mortality, 3.13% (95% CI: 1.88, 4.38) increase in stroke mortality, and 21.57% (95% CI: 12.59, 31.26) increase in ischemic heart disease (IHD) mortality. For hot effects over lag 0–7 days, a 1 °C increase in mean temperature above the hot thresholds was associated with a 25.18% (95% CI: 18.74, 31.96) increase in non-accidental mortality, 34.10% (95% CI: 25.63, 43.16) increase in cardiovascular mortality, 24.27% (95% CI: 7.55, 43.59) increase in respiratory mortality, 59.1% (95% CI: 41.81, 78.5) increase in stroke mortality, and 17.00% (95% CI: 7.91, 26.87) increase in IHD mortality. This study suggested that both low and high temperature were associated with increased mortality in Wuhan, and that mean temperature had better predictive ability than minimum and maximum temperature in the association between temperature and mortality. PMID:27438847

The application of exhaled breath analysis in racing Thoroughbreds and the influence of high intensity exercise and ambient temperature on the concentration of carbon monoxide and pH in exhaled breath.

PubMed

Cathcart, Michael P; Love, Sandy; Sutton, David G M; Reardon, Richard J M; Hughes, Kristopher J

2013-08-01

Analyses of exhaled breath (EB) and exhaled breath condensate (EBC) are non-invasive modalities for assessing the lower airways but these methods have not been applied to Thoroughbred racehorses in training. The aims of this study were to determine whether EB and EBC could be obtained from Thoroughbred racehorses in the field and to investigate the effects of exercise per se and during different ambient temperatures and humidity on exhaled concentrations of nitric oxide (eNO), carbon monoxide (eCO) and EBC pH. EB and EBC samples were obtained from 28 Thoroughbred racehorses pre- and post-exercise during warm (n=23) and/or cold (n=19) ambient temperatures. eNO was detected in 19/84 EB samples. eCO was measured in 39/42 EB samples pre-exercise (median 1.3 ppm) and concentrations decreased significantly post-exercise (median 0.8 ppm, P<0.005) and were associated with ambient temperature. EBC pH was 4.51 ± 0.23 pre-exercise and increased significantly post-exercise (4.79 ± 0.59, P=0.003). The study documented the collection of EB and EBC from Thoroughbred racehorses in a field setting. Alterations in concentrations of volatile gases and EBC pH occurred in response to exercise, and were likely to have been influenced by environmental factors. Copyright © 2012 Elsevier Ltd. All rights reserved.

SUBCOOLING DETECTOR

DOEpatents

McCann, J.A.

1963-12-17

A system for detecting and measuring directly the subcooling margin in a liquid bulk coolant is described. A thermocouple sensor is electrically heated, and a small amount of nearly stagnant bulk coolant is heated to the boiling point by this heated thermocouple. The sequential measurement of the original ambient temperature, zeroing out this ambient temperature, and then measuring the boiling temperature of the coolant permits direct determination of the subcooling margin of the ambient liquid. (AEC)

Ambient temperature effects on broadband UV-B measurements using fluorescent phosphor (MgWO4)-based detectors

NASA Technical Reports Server (NTRS)

Dichter, Bronislaw K.; Beaubien, David J.; Beaubien, Arthur F.

1994-01-01

Results of field tests on a group of broadband UV-B pyranometers are presented. A brief description of the instrument is given. The effects of ambient temperature on thermally unregulated fluorescent phosphor (Robertson type) meters are presented and compared with the performance of thermally stabilized instruments. Means for correcting data from thermally unregulated instruments, where the prevailing ambient temperatures are known, are outlined.

Synchronization of natural convection in thermostatically-controlled adjacent cavities

NASA Astrophysics Data System (ADS)

Chavez-Martinez, Rafael; Sanchez-Lopez, Mario; Solorio-Ordaz, Francisco Javier; Sen, Mihir

2017-11-01

Synchronization is a phenomenon observed in complex dynamical systems. It was first noticed by Huygens in the 17th century, and since then has been observed in systems of different types such as mechanical, biological and social. In thermal systems, numerical and analytical studies have found that two or more similar heat sources, with independent thermostatic temperature control and communicating with each other through a common interface, can have temperature oscillations. In the present study, laboratory experiments were carried out to study the thermal synchronization in two cuboid rooms separated by a common wall. Computer-based thermostats independently control the temperature of each cavity. The experiments show the effect of the ambient temperature and the initial condition in the cavities on the phase difference Δϕ . The results demonstrate in-phase and out-of-phase synchronization. An increase of the temperature difference between the cavity and the ambient, ΔT , increases Δϕ . When ΔT <2° C, Δϕ oscillates around zero. Δϕ is negative independently of the initial condition. The results of these experiments will be useful in the desing of heating in full-scale buildings. This work is supported by DGAPA-UNAM Grant PAPIIT-IN114216.

Foreign Object Damage Behavior of a SiC/SiC Composite at Ambient and Elevated Temperatures

NASA Technical Reports Server (NTRS)

Bhatt, Ramakrishna T.; Pereira, J. Michael; Gyekenyesi, John P.; Choi, Sung R.

2004-01-01

Foreign object damage (FOD) behavior of a gas-turbine grade SiC/SiC ceramic matrix composite (CMC) was determined at 25 and 1316 C, employing impact velocities from 115 to 440 meters per second by 1.59-mm diameter stell-ball projectiles. Two different types of specimen support were used at each temperature: fully supported and partially supported. For a given temperature, the degree of post-impact strength degradation increased with increasing impact velocity, and was greater in a partially supported configuration than in a fully supported one. The elevated-temperature FOD resistance of the composite, particularly under partially supported loading at higher impact velocities greater than or equal to 350 meters per second, was significantly less than the ambient-temperature counterpart, attributed to a weakening effect of the composite. For fully supported loading, frontal contact stress played a major role in generating composite damage; whereas, for partially supported loading, both frontal contact and backside bending stresses were combined sources of damage generation. The SiC/SiC composite was able to survive higher energy impacts without complete structural failure but suffered more strength affecting damage from low energy impacts than AS800 and SN282 silicon nitrides.

Temperature and seeding effects on the precipitation of scorodite from sulfate solutions under atmospheric-pressure conditions

NASA Astrophysics Data System (ADS)

Singhania, Shalabh; Wang, Qiankun; Filippou, Dimitrios; Demopoulos, George P.

2005-06-01

Arsenic is a major contaminant in the nonferrous extractive metallurgy. In the past 20 years, many studies have shown that it can be precipitated as relatively stable crystalline scorodite (FeAsO4·2H2O) by precipitation under ambient or elevated pressures. In the present study, an extensive program of scorodite precipitation tests under ambient pressure has shown that the rate of scorodite formation increases dramatically by a small increase in temperature from 85 °C to 100 °C. The beneficial effects of temperature are attributed to the higher thermodynamic stability of scorodite at elevated temperatures, but also to higher rates of secondary nuclei formation and crystal growth. In any case, irrespective of the precipitation temperature, the leachability of all scorodite precipitates observed in toxicity characterization leaching procedure (TCLP) tests is below 5 mg/L As. Another parameter examined in this study was seeding. It was observed that the higher the initial concentration of seed, the faster the precipitation. Precipitation of well-crystallized scorodite can be effected equally well on heterogeneous seed such as hematite (Fe2O3) or gypsum (CaSO4·2H2O) added externally or formed in situ.

Field study of dried blood spot specimens for HIV-1 drug resistance genotyping.

PubMed

Parry, C M; Parkin, N; Diallo, K; Mwebaza, S; Batamwita, R; DeVos, J; Bbosa, N; Lyagoba, F; Magambo, B; Jordan, M R; Downing, R; Zhang, G; Kaleebu, P; Yang, C; Bertagnolio, S

2014-08-01

Dried blood spots (DBS) are an alternative specimen type for HIV drug resistance genotyping in resource-limited settings. Data relating to the impact of DBS storage and shipment conditions on genotyping efficiency under field conditions are limited. We compared the genotyping efficiencies and resistance profiles of DBS stored and shipped at different temperatures to those of plasma specimens collected in parallel from patients receiving antiretroviral therapy in Uganda. Plasma and four DBS cards from anti-coagulated venous blood and a fifth card from finger-prick blood were prepared from 103 HIV patients with a median viral load (VL) of 57,062 copies/ml (range, 1,081 to 2,964,191). DBS were stored at ambient temperature for 2 or 4 weeks or frozen at -80 °C and shipped from Uganda to the United States at ambient temperature or frozen on dry ice for genotyping using a broadly sensitive in-house method. Plasma (97.1%) and DBS (98.1%) stored and shipped frozen had similar genotyping efficiencies. DBS stored frozen (97.1%) or at ambient temperature for 2 weeks (93.2%) and shipped at ambient temperature also had similar genotyping efficiencies. Genotyping efficiency was reduced for DBS stored at ambient temperature for 4 weeks (89.3%, P = 0.03) or prepared from finger-prick blood and stored at ambient temperature for 2 weeks (77.7%, P < 0.001) compared to DBS prepared from venous blood and handled similarly. Resistance profiles were similar between plasma and DBS specimens. This report delineates the optimal DBS collection, storage, and shipping conditions and opens a new avenue for cost-saving ambient-temperature DBS specimen shipments for HIV drug resistance (HIVDR) surveillances in resource-limited settings. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Dietary Supplementation of Chromium Can Alleviate Negative Impacts of Heat Stress on Performance, Carcass Yield, and Some Blood Hematology and Chemistry Indices of Growing Japanese Quail.

PubMed

El-Kholy, Mohamed Soliman; El-Hindawy, Mohamed Mohamed; Alagawany, Mahmoud; Abd El-Hack, Mohamed Ezzat; El-Sayed, Sabry Abd El-Gawad Abd El-Halim

2017-09-01

The main objective of this work was to investigate the impact of dietary chromium supplementation on growth indices, carcass yield, and some hematological and biochemical blood parameters of growing Japanese quails subjected to heat stress. A total of 360 unsexed 2-week-old Japanese quail chicks were used in a 2 × 3 factorial arrangement that had two ambient temperatures (23 ± 2 and 33 ± 2 °C) and three dietary chromium (0.00, 500, and 1000 μg Cr/kg diet as chromium picolinate). For induction of heat stress, the room temperature was set at 33 ± 2 °C from 2 to 6 weeks of age. Results showed that body weight, body weight gain, and feed intake were decreased for birds subjected to heat stress condition during 2 to 4 and 2 to 6 weeks of age. Feed conversion was not significantly (P > 0.05) affected by high ambient temperature throughout the experiment. Carcass, dressing, liver, and heart percentages were not influenced by the ambient temperature or dietary chromium or their combinations. Significant temperature × chromium combinations were observed for hemoglobin value (P = 0.025) and packed cell volume (P = 0.001). Cholesterol and glucose in plasma were increased (P = 0.004 or 0.022) in quails subjected to heat stress condition. Plasma measurements of total proteins, albumin, globulin, lipids, glucose, and A/G ratio of quail chicks were not influenced (P > 0.05) by chromium, while cholesterol was increased with increasing chromium level (P = 0.033). High ambient temperature or dietary chromium levels or their interactions did not (P > 0.05) affect plasma levels of aspartate transaminase (AST), alanine transaminase (ALT), triiodothyronine (T3), thyroxin (T4), or T3/T4 ratio of growing quails. From these observations, it can be concluded that dietary chromium supplementation of growing Japanese quail subjected to heat stress condition could beneficially affect growth performance and carcasses, as well as modulate the hematological and biochemical blood parameters, probably through modulating stress status.

Structural and ambient/sub-ambient temperature magnetic properties of Er-substituted cobalt-ferrites synthesized by sol-gel assisted auto-combustion method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prathapani, Sateesh; Department of Metallurgical Engineering and Materials Science, IIT-Bombay, Mumbai 400076; Jayaraman, Tanjore V., E-mail: ddas@uohyd.ernet.in, E-mail: tvjayaraman@gmail.com

2014-07-14

Er-substituted cobalt-ferrites CoFe{sub 2−x}Er{sub x}O{sub 4} (0 ≤ x ≤ 0.04) were synthesized by sol-gel assisted auto-combustion method. The precursor powders were calcined at 673–873 K for 4 h, subsequently pressed into pellets and sintered at 1273 K for 4 h. X-ray diffraction (XRD) confirmed the presence of the spinel phase for all the compositions and, additional orthoferrite phase for higher compositions (x = 0.03 and 0.04). The XRD spectra and the Transmission Electron Microscopy micrographs indicate that the nanocrystalline particulates of the Er-substituted cobalt ferrites have crystallite size of ∼120–200 nm. The magnetization curves show an increase in saturation magnetization (M{sub S}) and coercivity (H{sub C}) for Er-substituted cobalt-ferrites atmore » sub-ambient temperatures. M{sub S} for CoFe{sub 2}O{sub 4}, CoFe{sub 0.99}Er{sub 0.01}O{sub 4}, CoFe{sub 0.98}Er{sub 0.02}O{sub 4}, and CoFe{sub 0.97}Er{sub 0.03}O{sub 4} peak at 89.7 Am{sup 2}/kg, 89.3 Am{sup 2}/kg, 88.8 Am{sup 2}/kg, and 87.1 Am{sup 2}/kg, respectively, at a sub-ambient temperature of ∼150 K. H{sub C} substantially increases with decrease in temperature for all the compositions, while it peaks at x = 0.01−0.02 at all temperatures. The combination of Er content—x ∼ 0.02 and the temperature—∼5 K provides the maximum H{sub C} ∼ 984 kA/m. Er-substituted cobalt-ferrites have higher cubic anisotropy constant, K{sub 1}, compared to pure cobalt-ferrite at ambient/sub-ambient temperatures. K{sub 1} gradually increases for all compositions in the temperature decreasing from 300 to 100 K. While K{sub 1} peaks at ∼150 K for pure cobalt-ferrite, it peaks at ∼50 K for CoFe{sub 0.99}Er{sub 0.01}O{sub 4}, CoFe{sub 0.98}Er{sub 0.02}O{sub 4}, and CoFe{sub 0.96}Er{sub 0.04}O{sub 4}. The M{sub S} (∼88.7 Am{sup 2}/kg), at 5 K, for Er substituted cobalt-ferrite is close to the highest values reported for Sm and Gd substituted cobalt-ferrites. The M{sub S} (∼83.5 Am{sup 2}/kg) at 300 K for Er-substituted cobalt-ferrite is the highest among the lanthanide series element substituted cobalt-ferrites. The H{sub C} (at 5 K) for Er substituted cobalt-ferrite is close to the highest values observed for La, Ce, Nd, Sm, and Gd substituted cobalt-ferrites.« less

40 CFR 53.56 - Test for effect of variations in ambient pressure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... measurement accuracy. (iv) Coefficient of variability measurement accuracy. (v) Ambient pressure measurement... through the sample filter, measured in actual volume units at the temperature and pressure of the air as... volumetric flow rate corrections are made based on measurements of actual ambient temperature and pressure...

The microRNA156-SQUAMOSA PROMOTER BINDING PROTEIN-LIKE3 Module Regulates Ambient Temperature-Responsive Flowering via FLOWERING LOCUS T in Arabidopsis1[C][W][OA

PubMed Central

Kim, Jae Joon; Lee, Jeong Hwan; Kim, Wanhui; Jung, Hye Seung; Huijser, Peter; Ahn, Ji Hoon

2012-01-01

The flowering time of plants is affected by modest changes in ambient temperature. However, little is known about the regulation of ambient temperature-responsive flowering by small RNAs. In this study, we show that the microRNA156 (miR156)-SQUAMOSA PROMOTER BINDING PROTEIN-LIKE3 (SPL3) module directly regulates FLOWERING LOCUS T (FT) expression in the leaf to control ambient temperature-responsive flowering. Overexpression of miR156 led to more delayed flowering at a lower ambient temperature (16°C), which was associated with down-regulation of FT and FRUITFULL expression. Among miR156 target genes, SPL3 mRNA levels were mainly reduced, probably because miR156-mediated cleavage of SPL3 mRNA was higher at 16°C. Overexpression of miR156-resistant SPL3 [SPL3(−)] caused early flowering, regardless of the ambient temperature, which was associated with up-regulation of FT and FRUITFULL expression. Reduction of miR156 activity by target mimicry led to a phenotype similar to that of SUC2::rSPL3 plants. FT up-regulation was observed after dexamethasone treatment in GVG-rSPL3 plants. Misexpression and artificial microRNA-mediated suppression of FT in the leaf dramatically altered the ambient temperature-responsive flowering of plants overexpressing miR156 and SPL3(−). Chromatin immunoprecipitation assay showed that the SPL3 protein directly binds to GTAC motifs within the FT promoter. Lesions in TERMINAL FLOWER1, SHORT VEGETATIVE PHASE, and EARLY FLOWERING3 did not alter the expression of miR156 and SPL3. Taken together, our data suggest that the interaction between the miR156-SPL3 module and FT is part of the regulatory mechanism controlling flowering time in response to ambient temperature. PMID:22427344

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardiner, D. P.; Bardon, M. F.; Clark, W.

This study assessed differences in headspace flammability for summertime gasolines and new high-ethanol content fuel blends. The results apply to vehicle fuel tanks and underground storage tanks. Ambient temperature and fuel formulation effects on headspace vapor flammability of ethanol/gasoline blends were evaluated. Depending on the degree of tank filling, fuel type, and ambient temperature, fuel vapors in a tank can be flammable or non-flammable. Pure gasoline vapors in tanks generally are too rich to be flammable unless ambient temperatures are extremely low. High percentages of ethanol blended with gasoline can be less volatile than pure gasoline and can produce flammablemore » headspace vapors at common ambient temperatures. The study supports refinements of fuel ethanol volatility specifications and shows potential consequences of using noncompliant fuels. E85 is flammable at low temperatures; denatured ethanol is flammable at warmer temperatures. If both are stored at the same location, one or both of the tanks' headspace vapors will be flammable over a wide range of ambient temperatures. This is relevant to allowing consumers to splash -blend ethanol and gasoline at fueling stations. Fuels compliant with ASTM volatility specifications are relatively safe, but the E85 samples tested indicate that some ethanol fuels may produce flammable vapors.« less

Ambient temperature effect on pulse rate variability as an alternative to heart rate variability in young adult.

PubMed

Shin, Hangsik

2016-12-01

Pulse rate variability (PRV) is a promising physiological and analytic technique used as a substitute for heart rate variability (HRV). PRV is measured by pulse wave from various devices including mobile and wearable devices but HRV is only measured by an electrocardiogram (ECG). The purpose of this study was to evaluate PRV and HRV at various ambient temperatures and elaborate on the interchangeability of PRV and HRV. Twenty-eight healthy young subjects were enrolled in the experiment. We prepared temperature-controlled rooms and recorded the ECG and photoplethysmography (PPG) under temperature-controlled, constant humidity conditions. The rooms were kept at 17, 25, and 38 °C as low, moderate, and high ambient temperature environments, respectively. HRV and PRV were derived from the synchronized ECG and PPG measures and they were studied in time and frequency domain analysis for PRV/HRV ratio and pulse transit time (PTT). Similarity and differences between HRV and PRV were determined by a statistical analysis. PRV/HRV ratio analysis revealed that there was a significant difference between HRV and PRV for a given ambient temperature; this was with short-term variability measures such as SDNN SDSD or RMSSD, and HF-based variables including HF, LF/HF and normalized HF. In our analysis the absolute value of PTT was not significantly influenced by temperature. Standard deviation of PTT, however, showed significant difference not only between low and moderate temperatures but also between low and high temperatures. Our results suggest that ambient temperature induces a significant difference in PRV compared to HRV and that the difference becomes greater at a higher ambient temperature.

Impact of warm winters on microbial growth

NASA Astrophysics Data System (ADS)

Birgander, Johanna; Rousk, Johannes; Axel Olsson, Pål

2014-05-01

Growth of soil bacteria has an asymmetrical response to higher temperature with a gradual increase with increasing temperatures until an optimum after which a steep decline occurs. In laboratory studies it has been shown that by exposing a soil bacterial community to a temperature above the community's optimum temperature for two months, the bacterial community grows warm-adapted, and the optimum temperature of bacterial growth shifts towards higher temperatures. This result suggests a change in the intrinsic temperature dependence of bacterial growth, as temperature influenced the bacterial growth even though all other factors were kept constant. An intrinsic temperature dependence could be explained by either a change in the bacterial community composition, exchanging less tolerant bacteria towards more tolerant ones, or it could be due to adaptation within the bacteria present. No matter what the shift in temperature tolerance is due to, the shift could have ecosystem scale implications, as winters in northern Europe are getting warmer. To address the question of how microbes and plants are affected by warmer winters, a winter-warming experiment was established in a South Swedish grassland. Results suggest a positive response in microbial growth rate in plots where winter soil temperatures were around 6 °C above ambient. Both bacterial and fungal growth (leucine incorporation, and acetate into ergosterol incorporation, respectively) appeared stimulated, and there are two candidate explanations for these results. Either (i) warming directly influence microbial communities by modulating their temperature adaptation, or (ii) warming indirectly affected the microbial communities via temperature induced changes in bacterial growth conditions. The first explanation is in accordance with what has been shown in laboratory conditions (explained above), where the differences in the intrinsic temperature relationships were examined. To test this explanation the temperature relationships of the bacterial community from winter-warmed plots and plots with ambient soil temperatures were compared. No change in optimum temperature for growth could be detected, indicating that the microbial community has not been warm-adapted. This fits with what was seen also in the laboratory experiment where no changes in temperature response occurred when exposing bacteria to temperatures below 10 °C within two months. The increase in activity measured during winter should thereby be due to changes in environmental factors, which will be further investigated. One big difference between heated and control plots was that heated plots were snow free during the entire winter, while control plots were covered by a 10 cm snow cover. The plant community composition and flowering time also differed in the warmed and ambient plot.

Transient natural convection with density inversion from a horizontal cylinder

NASA Astrophysics Data System (ADS)

Wang, P.; Kahawita, R.; Nguyen, D. L.

1992-01-01

This paper is devoted to a numerical investigation of the free convection flow about a horizontal cylinder maintained at 0 °C in a water ambient close to the point of maximum density. Complete numerical solutions covering both the transient as well as steady state have been obtained. Principal results indicate that the proximity of the ambient temperature to the point of maximum density plays an important role in the type of convection pattern that may be obtained. When the ambient temperature is within 4.7 °C

Simulated Real-World Energy Impacts of a Thermally Sensitive Powertrain Considering Viscous Losses and Enrichment: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, E.; Gonder, J.; Lopp, S.

It is widely understood that cold ambient temperatures increase vehicle fuel consumption due to heat transfer losses, increased friction (increased viscosity lubricants), and enrichment strategies (accelerated catalyst heating). However, relatively little effort has been dedicated to thoroughly quantifying these impacts across a large set of real world drive cycle data and ambient conditions. This work leverages experimental dynamometer vehicle data collected under various drive cycles and ambient conditions to develop a simplified modeling framework for quantifying thermal effects on vehicle energy consumption. These models are applied over a wide array of real-world usage profiles and typical meteorological data to developmore » estimates of in-use fuel economy. The paper concludes with a discussion of how this integrated testing/modeling approach may be applied to quantify real-world, off-cycle fuel economy benefits of various technologies.« less

Temperature response surfaces for mortality risk of tree species with future drought

DOE PAGES

Adams, Henry D.; Barron-Gafford, Greg A.; Minor, Rebecca L.; ...

2017-11-17

Widespread, high levels of tree mortality, termed forest die-off, associated with drought and rising temperatures, are disrupting forests worldwide. Drought will likely become more frequent with climate change, but even without more frequent drought, higher temperatures can exacerbate tree water stress. The temperature sensitivity of drought-induced mortality of tree species has been evaluated experimentally for only single-step changes in temperature (ambient compared to ambient + increase) rather than as a response surface (multiple levels of temperature increase), which constrains our ability to relate changes in the driver with the biological response. Here we show that time-to-mortality during drought for seedlingsmore » of two western United States tree species, Pinus edulis (Engelm.) and Pinus ponderosa (Douglas ex C. Lawson), declined in continuous proportion with increasing temperature spanning a 7.7 °C increase. Although P. edulis outlived P. ponderosa at all temperatures, both species had similar relative declines in time-to-mortality as temperature increased (5.2% per °C for P. edulis; 5.8% per °C for P. ponderosa). When combined with the non-linear frequency distribution of drought duration—many more short droughts than long droughts—these findings point to a progressive increase in mortality events with global change due to warming alone and independent of additional changes in future drought frequency distributions. As such, dire future forest recruitment patterns are projected assuming the calculated 7–9 seedling mortality events per species by 2100 under business-as-usual warming occur, congruent with additional vulnerability predicted for adult trees from stressors like pathogens and pests. Our progressive projection for increased mortality events was driven primarily by the non-linear shape of the drought duration frequency distribution, a common climate feature of drought-affected regions. These results illustrate profound benefits for reducing emissions of carbon to the atmosphere from anthropogenic sources and slowing warming as rapidly as possible to maximize forest persistence.« less

Temperature response surfaces for mortality risk of tree species with future drought

NASA Astrophysics Data System (ADS)

Adams, Henry D.; Barron-Gafford, Greg A.; Minor, Rebecca L.; Gardea, Alfonso A.; Bentley, Lisa Patrick; Law, Darin J.; Breshears, David D.; McDowell, Nate G.; Huxman, Travis E.

2017-11-01

Widespread, high levels of tree mortality, termed forest die-off, associated with drought and rising temperatures, are disrupting forests worldwide. Drought will likely become more frequent with climate change, but even without more frequent drought, higher temperatures can exacerbate tree water stress. The temperature sensitivity of drought-induced mortality of tree species has been evaluated experimentally for only single-step changes in temperature (ambient compared to ambient + increase) rather than as a response surface (multiple levels of temperature increase), which constrains our ability to relate changes in the driver with the biological response. Here we show that time-to-mortality during drought for seedlings of two western United States tree species, Pinus edulis (Engelm.) and Pinus ponderosa (Douglas ex C. Lawson), declined in continuous proportion with increasing temperature spanning a 7.7 °C increase. Although P. edulis outlived P. ponderosa at all temperatures, both species had similar relative declines in time-to-mortality as temperature increased (5.2% per °C for P. edulis; 5.8% per °C for P. ponderosa). When combined with the non-linear frequency distribution of drought duration—many more short droughts than long droughts—these findings point to a progressive increase in mortality events with global change due to warming alone and independent of additional changes in future drought frequency distributions. As such, dire future forest recruitment patterns are projected assuming the calculated 7-9 seedling mortality events per species by 2100 under business-as-usual warming occur, congruent with additional vulnerability predicted for adult trees from stressors like pathogens and pests. Our progressive projection for increased mortality events was driven primarily by the non-linear shape of the drought duration frequency distribution, a common climate feature of drought-affected regions. These results illustrate profound benefits for reducing emissions of carbon to the atmosphere from anthropogenic sources and slowing warming as rapidly as possible to maximize forest persistence.

Temperature response surfaces for mortality risk of tree species with future drought

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, Henry D.; Barron-Gafford, Greg A.; Minor, Rebecca L.

Widespread, high levels of tree mortality, termed forest die-off, associated with drought and rising temperatures, are disrupting forests worldwide. Drought will likely become more frequent with climate change, but even without more frequent drought, higher temperatures can exacerbate tree water stress. The temperature sensitivity of drought-induced mortality of tree species has been evaluated experimentally for only single-step changes in temperature (ambient compared to ambient + increase) rather than as a response surface (multiple levels of temperature increase), which constrains our ability to relate changes in the driver with the biological response. Here we show that time-to-mortality during drought for seedlingsmore » of two western United States tree species, Pinus edulis (Engelm.) and Pinus ponderosa (Douglas ex C. Lawson), declined in continuous proportion with increasing temperature spanning a 7.7 °C increase. Although P. edulis outlived P . ponderosa at all temperatures, both species had similar relative declines in time-to-mortality as temperature increased (5.2% per °C for P. edulis; 5.8% per °C for P. ponderosa). When combined with the non-linear frequency distribution of drought duration—many more short droughts than long droughts—these findings point to a progressive increase in mortality events with global change due to warming alone and independent of additional changes in future drought frequency distributions. As such, dire future forest recruitment patterns are projected assuming the calculated 7-9 seedling mortality events per species by 2100 under business-as-usual warming occurs, congruent with additional vulnerability predicted for adult trees from stressors like pathogens and pests. Our progressive projection for increased mortality events was driven primarily by the non-linear shape of the drought duration frequency distribution, a common climate feature of drought-affected regions. These results illustrate profound benefits for reducing emissions of carbon to the atmosphere from anthropogenic sources and slowing warming as rapidly as possible to maximize forest persistence.« less

Temperature response surfaces for mortality risk of tree species with future drought

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, Henry D.; Barron-Gafford, Greg A.; Minor, Rebecca L.

Widespread, high levels of tree mortality, termed forest die-off, associated with drought and rising temperatures, are disrupting forests worldwide. Drought will likely become more frequent with climate change, but even without more frequent drought, higher temperatures can exacerbate tree water stress. The temperature sensitivity of drought-induced mortality of tree species has been evaluated experimentally for only single-step changes in temperature (ambient compared to ambient + increase) rather than as a response surface (multiple levels of temperature increase), which constrains our ability to relate changes in the driver with the biological response. Here we show that time-to-mortality during drought for seedlingsmore » of two western United States tree species, Pinus edulis (Engelm.) and Pinus ponderosa (Douglas ex C. Lawson), declined in continuous proportion with increasing temperature spanning a 7.7 °C increase. Although P. edulis outlived P. ponderosa at all temperatures, both species had similar relative declines in time-to-mortality as temperature increased (5.2% per °C for P. edulis; 5.8% per °C for P. ponderosa). When combined with the non-linear frequency distribution of drought duration—many more short droughts than long droughts—these findings point to a progressive increase in mortality events with global change due to warming alone and independent of additional changes in future drought frequency distributions. As such, dire future forest recruitment patterns are projected assuming the calculated 7–9 seedling mortality events per species by 2100 under business-as-usual warming occur, congruent with additional vulnerability predicted for adult trees from stressors like pathogens and pests. Our progressive projection for increased mortality events was driven primarily by the non-linear shape of the drought duration frequency distribution, a common climate feature of drought-affected regions. These results illustrate profound benefits for reducing emissions of carbon to the atmosphere from anthropogenic sources and slowing warming as rapidly as possible to maximize forest persistence.« less

The mRNA and miRNA transcriptomic landscape of Panax ginseng under the high ambient temperature.

PubMed

Jung, Inuk; Kang, Hyejin; Kim, Jang Uk; Chang, Hyeonsook; Kim, Sun; Jung, Woosuk

2018-03-19

Ginseng is a popular traditional herbal medicine in north-eastern Asia. It has been used for human health for over thousands of years. With the rise in global temperature, the production of Korean ginseng (Panax ginseng C.A.Meyer) in Korea have migrated from mid to northern parts of the Korean peninsula to escape from the various higher temperature related stresses. Under the high ambient temperature, vegetative growth was accelerated, which resulted in early flowering. This precocious phase change led to yield loss. Despite of its importance as a traditional medicine, biological mechanisms of ginseng has not been well studied and even the genome sequence of ginseng is yet to be determined due to its complex genome structure. Thus, it is challenging to investigate the molecular biology mechanisms at the transcript level. To investigate how ginseng responds to the high ambient temperature environment, we performed high throughput RNA sequencing and implemented a bioinformatics pipeline for the integrated analysis of small-RNA and mRNA-seq data without a reference genome. By performing reverse transcriptase (RT) PCR and sanger sequencing of transcripts that were assembled using our pipeline, we validated that their sequences were expressed in our samples. Furthermore, to investigate the interaction between genes and non-coding small RNAs and their regulation status under the high ambient temperature, we identified potential gene regulatory miRNAs. As a result, 100,672 contigs with significant expression level were identified and 6 known, 214 conserved and 60 potential novel miRNAs were predicted to be expressed under the high ambient temperature. Collectively, we have found that development, flowering and temperature responsive genes were induced under high ambient temperature, whereas photosynthesis related genes were repressed. Functional miRNAs were down-regulated under the high ambient temperature. Among them are miR156 and miR396 that target flowering (SPL6/9) and growth regulating genes (GRF) respectively.

Ambient temperature and air quality in relation to small for gestational age and term low birthweight

PubMed Central

Ha, Sandie; Zhu, Yeyi; Liu, Danping; Sherman, Seth; Mendola, Pauline

2017-01-01

Background Exposures to extreme ambient temperature and air pollution are linked to adverse birth outcomes, but the associations with small for gestational age (SGA) and term low birthweight (tLBW) are unclear. We aimed to investigate exposures to site-specific temperature extremes and selected criteria air pollutants in relation to SGA and tLBW. Methods We linked medical records of 220,572 singleton births (2002–2008) from 12 US sites to local temperature estimated by the Weather Research and Forecasting model, and air pollution estimated by modified Community Multiscale Air Quality models. Exposures to hot (>95th percentile) and cold (<5th percentile) were defined using site-specific distributions of daily temperature over three-month preconception, each trimester, and whole-pregnancy. Average concentrations of five criteria air pollutants and six fine particulate matter constituents were also calculated for these pregnancy windows. Poisson regression with generalized estimating equations calculated the relative risks (RR) and 95% confidence intervals for SGA (weight <10th percentile conditional on gestational age and sex) and tLBW (≥37 weeks and <2,500 grams) associated with an interquartile range increment of air pollutants, and cold or hot compared to mild (5–95th percentile) temperature. Models were adjusted for maternal demographics, lifestyle, and clinical factors, season, and site. Results Compared to mild temperature, cold exposure during trimester 2 [RR: 1.21 (1.05–1.38)], trimester 3 [RR: 1.18 (1.03–1.36)], and whole-pregnancy [RR: 2.57 (2.27–2.91)]; and hot exposure during trimester 3 [RR: 1.31 (1.15–1.50)] and whole-pregnancy [RR: 2.49 (2.20–2.83)] increased tLBW risk. No consistent association was observed between temperature and SGA. Air pollutant analyses were generally null but preconception elemental carbon was associated with a 4% increase in SGA while dust particles increased tLBW by 10%. Particulate matter ≤10 microns in the second trimester and whole pregnancy also appeared related to tLBW. Conclusions: Our findings suggest prenatal exposures to extreme ambient temperature relative to usual environment may increase tLBW risk. Given concerns related to climate change, these findings merit further investigation. PMID:28258738

The effect of ambient air temperature and precipitation on monthly counts of salmonellosis in four regions of Kazakhstan, Central Asia, in 2000-2010.

PubMed

Grjibovski, A M; Kosbayeva, A; Menne, B

2014-03-01

We studied associations between monthly counts of laboratory-confirmed cases of salmonellosis, ambient air temperature and precipitation in four settings in Kazakhstan. We observed a linear association between the number of cases of salmonellosis and mean monthly temperature during the same months only in Astana: an increase of 1°C was associated with a 5·5% [95% confidence interval (CI) 2·2-8·8] increase in the number of cases. A similar association, although not reaching the level of significance was observed in the Southern Kazakhstan region (3·5%, 95% CI -2·1 to 9·1). Positive association with precipitation with lag 2 was found in Astana: an increase of 1 mm was associated with a 0·5% (95% CI 0·1-1·0) increase in the number of cases. A similar association, but with lag 0 was observed in Southern Kazakhstan region (0·6%, 95% CI 0·1-1·1). The results may have implications for the future patterns of salmonellosis in Kazakhstan with regard to climate change.

A simple technique to prolong molding time during application of a fiberglass cast: An in vitro study

PubMed Central

Ayzenberg, Mark; Narvaez, Michael; Raphael, James

2018-01-01

Casting is routinely used for acute and post-operative immobilization and remains a cornerstone in the non-operative management of fractures and deformities. The application of a properly fitted and wellmolded cast, especially for a trainee, can be challenging. We present a simple method of prolonging cure time of fiberglass cast — placing ice in the dip water. Eight-ply, fiveinch fiberglass cast was circumferentially applied to an aluminum-wrapped cardboard cylinder. An electronic, 2-channel temperature sensor (TR-71wf Temp Logger, T&D Corporation, Matsumoto, Japan), accurate to 0.1ºC and accurate to ±0.3ºC, was placed between the fourth and fifth layers of fiberglass. Thirty total casts were tested using 9±1ºC (cold), 22±1ºC (ambient), and 36±1ºC (warm) dip water. Room temperature was maintained at 24±1ºC. Cast temperatures were measured during the exothermic reaction generated by the cast curing. Peak temperatures and cure times were recorded. Cure time was defined as the point of downward deflection on the timetemperature curve immediately after peak. Cure and peak temperatures were compared among groups using analysis of variance. Mean cure time was 3.5±0.1 minutes for warm water, 5.0±0.4 minutes for ambient water and 7.0±0.5 minutes for cold water. Peak temperature, measured between layers 4 and 5 of the cast material, was 36.6±0.8ºC for warm water, 31.1±1.4ºC for ambient water and 25.2±0.5ºC for cold water. Cold afforded, on average, an additional 2 minutes (40% increase) in cure time compared to ambient water and an additional 3.5 minutes (100% increase) compared to warm water. Cure time differences were significant (P<0.001) for all groups, as were peak temperature differences (P<0.001). Temperatures concerning for development of burns were never reached. Utilizing iced dip water when casting is a simple and effective method to prolong the time available for cast application. Orthopedic residents and trainees may find this useful in learning to fabricate a high quality cast. For the experienced orthopedic surgeon, this method eliminates the need to bridge longlimb casts and facilitates the application of complex casts. PMID:29770174

Influence of ambient temperature and diurnal temperature range on incidence of cardiac arrhythmias

NASA Astrophysics Data System (ADS)

Kim, Jayeun; Kim, Ho

2017-03-01

We investigated the association between ambient temperature and diurnal temperature range (DTR) and the exacerbation of arrhythmia symptoms, using data from 31,629 arrhythmia-related emergency department (ED) visits in Seoul, Korea. Linear regression analyses with allowances for over-dispersion were applied to temperature variables and ED visits, adjusted for various environmental factors. The effects were expressed as percentage changes in the risk of arrhythmia-related ED visits up to 5 days later, with 95 % confidence intervals (CI), per 1 °C increase in DTR and 1 °C decrease in mean temperature. The overall risk of ED visits increased by 1.06 % (95 % CI 0.39 %, 1.73 %) for temperature and by 1.84 % (0.34, 3.37 %) for DTR. A season-specific effect was detected for temperature during both fall (1.18 % [0.01, 2.37 %]) and winter (0.87 % [0.07, 1.67 %]), and for DTR during spring (3.76 % [0.34, 7.29 %]). Females were more vulnerable, with 1.57 % [0.56, 2.59 %] and 3.84 % [1.53, 6.20 %] for the changes in temperature and DTR, respectively. An age-specific effect was detected for DTR, with 3.13 % [0.95, 5.36 %] for age ≥ 65 years, while a greater increased risk with temperature decrease was observed among those aged <65 (1.08 % [0.17, 2.00 %]) than among those aged ≥65 (1.02 % [0.06, 1.99 %]). Cardiac arrest was inversely related with temperature (1.61 % [0.46, 2.79 %]), while other cardiac arrhythmias depended more on the change in DTR (4.72 % [0.37, 9.26 %]). These findings provide evidence that low-temperature and elevated DTR influence the occurrence of arrhythmia exacerbations or symptoms, suggesting a possible strategy for reducing risk by encouraging vulnerable populations to minimize exposure.

Seasonal reproductive endothermy in tegu lizards.

PubMed

Tattersall, Glenn J; Leite, Cleo A C; Sanders, Colin E; Cadena, Viviana; Andrade, Denis V; Abe, Augusto S; Milsom, William K

2016-01-01

With some notable exceptions, small ectothermic vertebrates are incapable of endogenously sustaining a body temperature substantially above ambient temperature. This view was challenged by our observations of nighttime body temperatures sustained well above ambient (up to 10°C) during the reproductive season in tegu lizards (~2 kg). This led us to hypothesize that tegus have an enhanced capacity to augment heat production and heat conservation. Increased metabolic rates and decreased thermal conductance are the same mechanisms involved in body temperature regulation in those vertebrates traditionally acknowledged as "true endotherms": the birds and mammals. The appreciation that a modern ectotherm the size of the earliest mammals can sustain an elevated body temperature through metabolic rates approaching that of endotherms enlightens the debate over endothermy origins, providing support for the parental care model of endothermy, but not for the assimilation capacity model of endothermy. It also indicates that, contrary to prevailing notions, ectotherms can engage in facultative endothermy, providing a physiological analog in the evolutionary transition to true endothermy.

Seasonal reproductive endothermy in tegu lizards

PubMed Central

Tattersall, Glenn J.; Leite, Cleo A. C.; Sanders, Colin E.; Cadena, Viviana; Andrade, Denis V.; Abe, Augusto S.; Milsom, William K.

2016-01-01

With some notable exceptions, small ectothermic vertebrates are incapable of endogenously sustaining a body temperature substantially above ambient temperature. This view was challenged by our observations of nighttime body temperatures sustained well above ambient (up to 10°C) during the reproductive season in tegu lizards (~2 kg). This led us to hypothesize that tegus have an enhanced capacity to augment heat production and heat conservation. Increased metabolic rates and decreased thermal conductance are the same mechanisms involved in body temperature regulation in those vertebrates traditionally acknowledged as “true endotherms”: the birds and mammals. The appreciation that a modern ectotherm the size of the earliest mammals can sustain an elevated body temperature through metabolic rates approaching that of endotherms enlightens the debate over endothermy origins, providing support for the parental care model of endothermy, but not for the assimilation capacity model of endothermy. It also indicates that, contrary to prevailing notions, ectotherms can engage in facultative endothermy, providing a physiological analog in the evolutionary transition to true endothermy. PMID:26844295

Ambient temperature thermoelectric performance of thermally evaporated p-type Bi-Sb-Te thin films

NASA Astrophysics Data System (ADS)

Singh, Sukhdeep; Singh, Janpreet; Tripathi, S. K.

2018-04-01

Bismuth antimony telluride (BST) compounds have shown a promising performance in low to medium temperature thermoelectric (TE) conversion. One such composition, Bi1.2Sb0.8Te3, was synthesized by melting elemental entities and thin films of the as-synthesized material were deposited by thermal evaporation. X-Ray Diffraction analysis was conducted to study the crystallographic phases and other structural properties. Electrical conductivity and Seebeck coefficient measurements of as-prepared thin films were conducted in the temperature range from 303-363 K with a view to study ambient temperature application of the synthesized material for power generation in which an increasing trend was observed in the Seebeck coefficient. Electrical conductivity displayed a maximum value of 0.22 × 104 Sm-1 that was comparable to other Bi-Sb-Te compositions whereas power factor had its peak at 323 K. These trends observed in electrical properties indicate that synthesized material can be used for room temperature TE module fabrication.

Method for Aluminum Oxide Thin Films Prepared through Low Temperature Atomic Layer Deposition for Encapsulating Organic Electroluminescent Devices

PubMed Central

Li, Hui-Ying; Liu, Yun-Fei; Duan, Yu; Yang, Yong-Qiang; Lu, Yi-Nan

2015-01-01

Preparation of dense alumina (Al2O3) thin film through atomic layer deposition (ALD) provides a pathway to achieve the encapsulation of organic light emitting devices (OLED). Unlike traditional ALD which is usually executed at higher reaction n temperatures that may affect the performance of OLED, this application discusses the development on preparation of ALD thin film at a low temperature. One concern of ALD is the suppressing effect of ambient temperature on uniformity of thin film. To mitigate this issue, the pumping time in each reaction cycle was increased during the preparation process, which removed reaction byproducts and inhibited the formation of vacancies. As a result, the obtained thin film had both high uniformity and density properties, which provided an excellent encapsulation performance. The results from microstructure morphology analysis, water vapor transmission rate, and lifetime test showed that the difference in uniformity between thin films prepared at low temperatures, with increased pumping time, and high temperatures was small and there was no obvious influence of increased pumping time on light emitting performance. Meanwhile, the permeability for water vapor of the thin film prepared at a low temperature was found to reach as low as 1.5 × 10−4 g/(m2·day) under ambient conditions of 25 °C and 60% relative humidity, indicating a potential extension in the lifetime for the OLED. PMID:28787960

Boiling regimes of impacting drops on a heated substrate under reduced pressure

NASA Astrophysics Data System (ADS)

van Limbeek, Michiel A. J.; Hoefnagels, Paul B. J.; Shirota, Minori; Sun, Chao; Lohse, Detlef

2018-05-01

We experimentally investigate the boiling behavior of impacting ethanol drops on a heated smooth sapphire substrate at pressures ranging from P =0.13 bar to atmospheric pressure. We employ frustrated total internal reflection imaging to study the wetting dynamics of the contact between the drop and the substrate. The spreading drop can be in full contact (contact boiling), it can partially touch (transition boiling), or the drop can be fully levitated (Leidenfrost boiling). We show that the temperature of the boundary between contact and transition boiling shows at most a weak dependence on the impact velocity, but a significant decrease with decreasing ambient gas pressure. A striking correspondence is found between the temperature of this boundary and the static Leidenfrost temperature for all pressures. We therefore conclude that both phenomena share the same mechanism and are dominated by the dynamics taking place at the contact line. On the other hand, the boundary between transition boiling and Leidenfrost boiling, i.e., the dynamic Leidenfrost temperature, increases for increasing impact velocity for all ambient gas pressures. Moreover, the dynamic Leidenfrost temperature coincides for pressures between P =0.13 and 0.54 bar, whereas for atmospheric pressure the dynamic Leidenfrost temperature is slightly elevated. This indicates that the dynamic Leidenfrost temperature is at most weakly dependent on the enhanced evaporation by the lower saturation temperature of the liquid.

Hand and finger dexterity as a function of skin temperature, EMG, and ambient condition.

PubMed

Chen, Wen-Lin; Shih, Yuh-Chuan; Chi, Chia-Fen

2010-06-01

This article examines the changes in skin temperature (finger, hand, forearm), manual performance (hand dexterity and strength), and forearm surface electromyograph (EMG) through 40-min, 11 degrees C water cooling followed by 15-min, 34 degrees C water rewarming; additionally, it explores the relationship between dexterity and the factors of skin temperature, EMG, and ambient condition. Hand exposure in cold conditions is unavoidable and significantly affects manual performance. Two tasks requiring gross and fine dexterity were designed, namely, nut loosening and pin insertion, respectively. The nested-factorial design includes factors of gender, participant (nested within gender), immersion duration, muscle type (for EMG), and location (for skin temperature). The responses are changes in dexterity, skin temperature, normalized amplitude of EMG, and grip strength. Finally, factor analysis and stepwise regression are used to explore factors affecting hand and finger dexterity. Dexterity, EMG, and skin temperature fell with prolonged cooling, but the EMG of the flexor digitorum superficialis remained almost unchanged during the nut loosening task. All responses but the forearm skin temperature recovered to the baseline level at the end of rewarming. The three factors extracted by factor analysis are termed skin temperature, ambient condition, and EMG. They explain approximately two thirds of the variation of the linear models for both dexterities, and the factor of skin temperature is the most influential. Sustained cooling and warming significantly decreases and increases finger, hand, and forearm skin temperature. Dexterity, strength, and EMG are positively correlated to skin temperature. Therefore, keeping the finger, hand, and forearm warm is important to maintaining hand performance. The findings could be helpful to building safety guidelines for working in cold environments.

Ambient temperature and genotype differentially affect developmental and phenotypic plasticity in Arabidopsis thaliana.

PubMed

Ibañez, Carla; Poeschl, Yvonne; Peterson, Tom; Bellstädt, Julia; Denk, Kathrin; Gogol-Döring, Andreas; Quint, Marcel; Delker, Carolin

2017-07-06

Global increase in ambient temperatures constitute a significant challenge to wild and cultivated plant species. Forward genetic analyses of individual temperature-responsive traits have resulted in the identification of several signaling and response components. However, a comprehensive knowledge about temperature sensitivity of different developmental stages and the contribution of natural variation is still scarce and fragmented at best. Here, we systematically analyze thermomorphogenesis throughout a complete life cycle in ten natural Arabidopsis thaliana accessions grown under long day conditions in four different temperatures ranging from 16 to 28 °C. We used Q 10 , GxE, phenotypic divergence and correlation analyses to assess temperature sensitivity and genotype effects of more than 30 morphometric and developmental traits representing five phenotype classes. We found that genotype and temperature differentially affected plant growth and development with variing strengths. Furthermore, overall correlations among phenotypic temperature responses was relatively low which seems to be caused by differential capacities for temperature adaptations of individual accessions. Genotype-specific temperature responses may be attractive targets for future forward genetic approaches and accession-specific thermomorphogenesis maps may aid the assessment of functional relevance of known and novel regulatory components.

Increasing soil temperature in a northern hardwood forest: effects on elemental dynamics and primary productivity

Treesearch

Patrick J. McHale; Myron J. Mitchell; Dudley J. Raynal; Francis P. Bowles

1996-01-01

To investigate the effects of elevated soil temperatures on a forest ecosystem, heating cables were buried at a depth of 5 cm within the forest floor of a northern hardwood forest at the Huntington Wildlife Forest (Adirondack Mountains, New York). Temperature was elevated 2.5, 5.0 and 7.5?C above ambient, during May - September in both 1993 and 1994. Various aspects of...

Effect of extreme temperatures on battery charging and performance of electric vehicles

NASA Astrophysics Data System (ADS)

Lindgren, Juuso; Lund, Peter D.

2016-10-01

Extreme temperatures pose several limitations to electric vehicle (EV) performance and charging. To investigate these effects, we combine a hybrid artificial neural network-empirical Li-ion battery model with a lumped capacitance EV thermal model to study how temperature will affect the performance of an EV fleet. We find that at -10 °C, the self-weighted mean battery charging power (SWMCP) decreases by 15% compared to standard 20 °C temperature. Active battery thermal management (BTM) during parking can improve SWMCP for individual vehicles, especially if vehicles are charged both at home and at workplace; the median SWMCP is increased by over 30%. Efficiency (km/kWh) of the vehicle fleet is maximized when ambient temperature is close to 20 °C. At low (-10 °C) and high (+40 °C) ambient temperatures, cabin preconditioning and BTM during parking can improve the median efficiency by 8% and 9%, respectively. At -10 °C, preconditioning and BTM during parking can also improve the fleet SOC by 3-6%-units, but this also introduces a ;base; load of around 140 W per vehicle. Finally, we observe that the utility of the fleet can be increased by 5%-units by adding 3.6 kW chargers to workplaces, but further improved charging infrastructure would bring little additional benefit.

Tribological study of novel metal-doped carbon-based coatings with enhanced thermal stability

NASA Astrophysics Data System (ADS)

Mandal, Paranjayee

Low friction and high temperature wear resistant PVD coatings are in high demand for use on engine components, which operate in extreme environment. Diamond-like-carbon (DLC) coatings are extensively used for this purpose due to their excellent tribological properties. However, DLC degrades at high temperature and pressure conditions leading to significant increase in friction and wear rate even in the presence of lubricant. To withstand high working temperature and simultaneously maintain improved tribological properties in lubricated condition at ambient and at high temperature, both the transitional metals Mo and W are simultaneously introduced in a carbon-based coating (Mo-W-C) for the first time utilising the benefits of smart material combination and High Power Impulse Magnetron Sputtering (HIPIMS).This research includes development of Mo-W-C coating and investigation of thermal stability and tribological properties at ambient and high temperatures. The as-deposited Mo-W-C coating contains nanocrystalline almost X-ray amorphous structure and show dense microstructure, good adhesion with substrate (Lc -80 N) and high hardness (-17 GPa). During boundary lubricated sliding (commercially available engine oil without friction modifier used as lubricant) at ambient temperature, Mo-W-C coating outperforms commercially available state-of-the-art DLC coatings by providing significantly low friction (u- 0.03 - 0.05) and excellent wear resistance (no measurable wear). When lubricated sliding tests are carried out at 200°C, Mo-W-C coating provides low friction similar to ambient temperature, whereas degradation of DLC coating properties fails to maintain low friction coefficient.A range of surface analyses techniques reveal "in-situ" formation of solid lubricants (WS2 and M0S2) at the tribo-contacts due to tribochemically reactive wear mechanism at ambient and high temperature. Mo-W-C coating reacts with EP additives present in the engine oil during sliding to form WS2 and M0S2. This mechanism is believed to be the key-factor for low friction properties of Mo-W-C coating and presence of graphitic carbon particles further benefits the friction behaviour. It is observed that low friction is achieved mostly due to formation of WS2 at ambient temperature, whereas formation of both WS2 and M0S2 significantly decreases the friction of Mo-W-C coating at high temperature. This further indicates importance of combined Mo and W doping over single-metal doping into carbon-based coatings.Isothermal oxidation tests indicate that Mo-W-C coating preserves it's as-deposited graphitic nature up to 500°C, whereas local delamination of DLC coating leads to substrate exposure and loss of its diamond-like structure at the same temperature. Further, thermo-gravimetric tests confirm excellent thermal stability of Mo-W-C coating compared to DLC. Mo-W-C coating resists oxidation up to 800°C and no coating delamination is observed due to retained coating integrity and its strong adhesion with substrate. On the other hand, state-of-the-art DLC coating starts to delaminate beyond 380°C.The test results confirm that Mo-W-C coating sustains high working temperature and simultaneously maintains improved tribological properties during boundary lubricated condition at ambient and high temperature. Thus Mo-W-C coating is a suitable candidate for low friction and high temperature wear resistant applications compared to commercially available state-of-the-art DLC coatings.

Contrasting effects of elevated CO2 and warming on temperature sensitivity of soil organic matter decomposition in a Chinese paddy field.

PubMed

Chen, Zhaozhi; Wang, Bingyu; Wang, Jinyang; Pan, Genxing; Xiong, Zhengqin

2015-10-01

Climate changes including elevated CO2 and temperature have been known to affect soil carbon (C) storage, while the effects of climate changes on the temperature sensitivity of soil organic matter (SOM) are unclear. A 365-day laboratory incubation was used to investigate the temperature sensitivity for decomposition of labile (Q 10-L) and recalcitrant (Q 10-R) SOMs by comparing the time required to decompose a given amount of C at 25 and 35 °C. Soils were collected from a paddy field that was subjected to four treatments: ambient CO2 and temperature, elevated CO2 (500 μmol/mol), enhanced temperature (+2 °C), and their combination. The results showed that the temperature sensitivity of SOM decomposition increased with increasing SOM recalcitrance in this paddy soil (Q 10-L = 2.21 ± 0.16 vs. Q 10-R = 2.78 ± 0.42; mean ± SD). Elevated CO2 and enhanced temperature showed contrasting effects on the temperature sensitivity of SOM decomposition. Elevated CO2 stimulated Q 10-R but had no effect on Q 10-L; in contrast, enhanced temperature increased Q 10-L but had no effect on Q 10-R. Furthermore, the elevated CO2 combined with enhanced temperature treatment significantly increased Q 10-L and Q 10-R by 18.9 and 10.2 %, respectively, compared to the ambient conditions. Results suggested that the responses of SOM to temperature, especially for the recalcitrant SOM pool, were altered by climate changes. The greatly enhanced temperature sensitivity of SOM decomposition by elevated CO2 and temperature indicates that more CO2 will be released to the atmosphere and losses of soil C may be even greater than that previously expected in paddy field.

Ambient temperature regulates the expression of a small set of sRNAs influencing plant development through NF-YA2 and YUC2.

PubMed

Gyula, Péter; Baksa, Ivett; Tóth, Tamás; Mohorianu, Irina; Dalmay, Tamás; Szittya, György

2018-06-01

Plants substantially alter their developmental program upon changes in the ambient temperature. The 21-24 nt small RNAs (sRNAs) are important gene expression regulators, which play a major role in development and adaptation. However, little is known about how the different sRNA classes respond to changes in the ambient temperature. We profiled the sRNA populations in four different tissues of Arabidopsis thaliana plants grown at 15, 21 and 27 °C. We found that only a small fraction (0.6%) of the sRNA loci are ambient temperature-controlled. We identified thermoresponsive miRNAs and identified their target genes using degradome libraries. We verified that the target of the thermoregulated miR169, NF-YA2, is also ambient temperature-regulated. NF-YA2, as the component of the conserved transcriptional regulator NF-Y complex, binds the promoter of the flowering time regulator FT and the auxin biosynthesis gene YUC2. Other differentially expressed loci include thermoresponsive phased siRNA loci that target various auxin pathway genes and tRNA fragments. Furthermore, a temperature dependent 24-nt heterochromatic siRNA locus in the promoter of YUC2 may contribute to the epigenetic regulation of auxin homeostasis. This holistic approach facilitated a better understanding of the role of different sRNA classes in ambient temperature adaptation of plants. This article is protected by copyright. All rights reserved.

Normal variation in thermal radiated temperature in cattle: implications for foot-and-mouth disease detection.

PubMed

Gloster, John; Ebert, Katja; Gubbins, Simon; Bashiruddin, John; Paton, David J

2011-11-21

Thermal imagers have been used in a number of disciplines to record animal surface temperatures and as a result detect temperature distributions and abnormalities requiring a particular course of action. Some work, with animals infected with foot-and-mouth disease virus, has suggested that the technique might be used to identify animals in the early stages of disease. In this study, images of 19 healthy cattle have been taken over an extended period to determine hoof and especially coronary band temperatures (a common site for the development of FMD lesions) and eye temperatures (as a surrogate for core body temperature) and to examine how these vary with time and ambient conditions. The results showed that under UK conditions an animal's hoof temperature varied from 10°C to 36°C and was primarily influenced by the ambient temperature and the animal's activity immediately prior to measurement. Eye temperatures were not affected by ambient temperature and are a useful indicator of core body temperature. Given the variation in temperature of the hooves of normal animals under various environmental conditions the use of a single threshold hoof temperature will be at best a modest predictive indicator of early FMD, even if ambient temperature is factored into the evaluation.

Seasonal Variability May Affect Microbial Decomposers and Leaf Decomposition More Than Warming in Streams.

PubMed

Duarte, Sofia; Cássio, Fernanda; Ferreira, Verónica; Canhoto, Cristina; Pascoal, Cláudia

2016-08-01

Ongoing climate change is expected to affect the diversity and activity of aquatic microbes, which play a key role in plant litter decomposition in forest streams. We used a before-after control-impact (BACI) design to study the effects of warming on a forest stream reach. The stream reach was divided by a longitudinal barrier, and during 1 year (ambient year) both stream halves were at ambient temperature, while in the second year (warmed year) the temperature in one stream half was increased by ca. 3 °C above ambient temperature (experimental half). Fine-mesh bags containing oak (Quercus robur L.) leaves were immersed in both stream halves for up to 60 days in spring and autumn of the ambient and warmed years. We assessed leaf-associated microbial diversity by denaturing gradient gel electrophoresis and identification of fungal conidial morphotypes and microbial activity by quantifying leaf mass loss and productivity of fungi and bacteria. In the ambient year, no differences were found in leaf decomposition rates and microbial productivities either between seasons or stream halves. In the warmed year, phosphorus concentration in the stream water, leaf decomposition rates, and productivity of bacteria were higher in spring than in autumn. They did not differ between stream halves, except for leaf decomposition, which was higher in the experimental half in spring. Fungal and bacterial communities differed between seasons in both years. Seasonal changes in stream water variables had a greater impact on the activity and diversity of microbial decomposers than a warming regime simulating a predicted global warming scenario.

Significant mobility improvement of amorphous In-Ga-Zn-O thin-film transistors annealed in a low temperature wet ambient environment

NASA Astrophysics Data System (ADS)

Jallorina, Michael Paul A.; Bermundo, Juan Paolo S.; Fujii, Mami N.; Ishikawa, Yasuaki; Uraoka, Yukiharu

2018-05-01

Transparent amorphous oxide semiconducting materials such as amorphous InGaZnO used in thin film transistors (TFTs) are typically annealed at temperatures higher than 250 °C to remove any defects present and improve the electrical characteristics of the device. Previous research has shown that low cost and low temperature methods improve the electrical characteristics of the TFT. With the aid of surface and bulk characterization techniques in comparison to the device characteristics, this work aims to elucidate further on the improvement mechanisms of wet and dry annealing ambients that affect the electrical characteristics of the device. Secondary Ion Mass Spectrometry results show that despite outward diffusion of -H and -OH species, humid annealing ambients counteract outward diffusion of these species, leading to defect sites which can be passivated by the wet ambient. X-ray Photoelectron Spectroscopy results show that for devices annealed for only 30 min in a wet annealing environment, the concentration of metal-oxide bonds increased by as much as 21.8% and defects such as oxygen vacancies were reduced by as much as 18.2% compared to an unannealed device. Our work shows that due to the oxidizing power of water vapor, defects are reduced, and overall electrical characteristics are improved as evidenced with the 150 °C wet O2, 30 min annealed sample which exhibited the highest mobility of 5.00 cm2/V s, compared to 2.36 cm2/V s for a sample that was annealed at 150 °C in a dry ambient atmospheric environment for 2 h.

Factors related to the attraction of flies at a biosolids composting facility (Bariloche, Argentina).

PubMed

Laos, F; Semenas, L; Labud, V

2004-07-26

The composting process is used to treat biosolids from the Wastewater Treatment Plant of Bariloche (NW Patagonia, Argentina). Since 1998, an odourless, innocuous and stable organic amendment has been produced at the Biosolids Composting Plant of Bariloche. However, volatile compounds produced during this process, attract different vectors, mainly insects belonging to the Order Diptera, particularly in summer. To evaluate factors associated with the attraction of Diptera to composting windrows, volatile compounds, wind velocity, ambient and windrow temperatures were measured and their relationships with the taxa of flies found were determined. Sampling was conducted several months on newly formed windrows during 3 weeks of the thermophilic composting period. Composite samples from each windrow were taken on the first day of each sampling week, from November 1999 to March 2000 to analyze volatile compounds using an 'electronic nose'. Windrow and ambient temperatures and wind velocity were recorded on three consecutive days of each week, from January to March 2000; also the capture of flies was performed in this period. A weekly mean value was calculated for each environmental variable. Canonical Correspondence Analysis was employed to determine relationships between taxa of flies and the studied factors. The electronic nose discriminated among odours emitted, differentiating windrows by the bulking agent employed and by week of the thermophilic composting period. Ambient temperatures increased slightly during the sampling weeks; the highest values of wind velocity were registered during the second sampling week while windrow temperatures were sustained approximately 60 degrees C. Canonical Correspondence Analysis showed that attraction of flies to composting windrows was related to minimum and maximum ambient temperatures and volatile compounds for Muscina stabulans, Fannia sp. and Acaliptratae and to wind velocity for Ophyra sp., Sarcophaga sp., Cochliomyia macellaria and Phaenicia sericata. Copyright 2004 Elsevier B.V.

Effects of ambient temperature on stroke hospital admissions: Results from a time-series analysis of 104,432 strokes in Guangzhou, China.

PubMed

Guo, Pi; Zheng, Murui; Feng, Wenru; Wu, Jiagang; Deng, Changyu; Luo, Ganfeng; Wang, Li; Pan, Bingying; Liu, Huazhang

2017-02-15

Stroke is a main cause of death and public health burden in China. The evidence on the burden of different strokes attack attribute to ambient temperature in China is limited. This study aimed to show the characteristics of stroke attack and the attributable risk due to temperature based on hospital admission data in Guangzhou, one of the most developed cities in China. From January 1, 2013 to December 31, 2015, 104,432 stroke hospitalizations in Guangzhou residents from 67 hospitals for stroke sentinel surveillance were registered. Characteristics of hospital admissions by gender, age group, calendar year and stroke subtype were analyzed, and distributed lag non-linear models were applied to evaluate the effects of temperature on stroke attack admissions. Stroke attack admissions increased from 31,851 to 36,755 through 2013 to 2015, increasing by 15.4%. An increasing trend in the risk of stroke attack with age was observed, irrespectively of stroke subtype and calendar year. People with hypertension were more likely to have an associated stroke than people without that. The effects of cold temperature on attack admissions for CBI and ICH strokes were significant. Overall, the percentages of CBI and ICH attack admissions attribute to cold temperature were 9.06% (95% CI: 1.84, 15.00) and 15.09% (95% CI: 5.86, 21.96), respectively. Besides, elderly people were more vulnerable to cold temperature than the young. Measures should be taken to increase public awareness about the ill effects of cold temperature on stroke attack, and educate the public about self-protection. Copyright © 2016 Elsevier B.V. All rights reserved.

Hyperactivity in Anorexia Nervosa: Warming Up Not Just Burning-Off Calories

PubMed Central

Carrera, Olaia; Adan, Roger A. H.; Gutierrez, Emilio; Danner, Unna N.; Hoek, Hans W.; van Elburg, Annemarie A.; Kas, Martien J. H.

2012-01-01

Excessive physical activity is a common feature in Anorexia Nervosa (AN) that interferes with the recovery process. Animal models have demonstrated that ambient temperature modulates physical activity in semi-starved animals. The aim of the present study was to assess the effect of ambient temperature on physical activity in AN patients in the acute phase of the illness. Thirty-seven patients with AN wore an accelerometer to measure physical activity within the first week of contacting a specialized eating disorder center. Standardized measures of anxiety, depression and eating disorder psychopathology were assessed. Corresponding daily values for ambient temperature were obtained from local meteorological stations. Ambient temperature was negatively correlated with physical activity (p = −.405) and was the only variable that accounted for a significant portion of the variance in physical activity (p = .034). Consistent with recent research with an analogous animal model of the disorder, our findings suggest that ambient temperature is a critical factor contributing to the expression of excessive physical activity levels in AN. Keeping patients warm may prove to be a beneficial treatment option for this symptom. PMID:22848634

16 CFR 1203.13 - Test schedule.

Code of Federal Regulations, 2014 CFR

2014-01-01

... helmets, as designated in Table 1203.13, shall be tested for peripheral vision in accordance with § 1203... conditioned in the ambient, high temperature, low temperature, and water immersion environments as follows: helmets 1 and 5—ambient; helmets 2 and 7—high temperature; helmets 3 and 6—low temperature; and helmets 4...

16 CFR § 1203.13 - Test schedule.

Code of Federal Regulations, 2013 CFR

2013-01-01

... helmets, as designated in Table 1203.13, shall be tested for peripheral vision in accordance with § 1203... conditioned in the ambient, high temperature, low temperature, and water immersion environments as follows: helmets 1 and 5—ambient; helmets 2 and 7—high temperature; helmets 3 and 6—low temperature; and helmets 4...

16 CFR 1203.13 - Test schedule.

Code of Federal Regulations, 2011 CFR

2011-01-01

... helmets, as designated in Table 1203.13, shall be tested for peripheral vision in accordance with § 1203... conditioned in the ambient, high temperature, low temperature, and water immersion environments as follows: helmets 1 and 5—ambient; helmets 2 and 7—high temperature; helmets 3 and 6—low temperature; and helmets 4...

Investigation of structural and magnetic properties of rapidly-solidified iron-silicon alloys at ambient and elevated temperatures

DOE PAGES

Jayaraman, T. V.; Meka, V. M.; Jiang, X.; ...

2018-01-09

Here we investigated the ambient temperature structural properties (thickness, width, microstructure, and lattice parameter), and the ambient and high temperature (up to 900 K) direct current (DC) magnetic properties—saturation magnetization (M S) and intrinsic coercivity (H CI)—of rapidly-solidified (melt-spun) Fe-x wt.% Si (x = 3, 5, & 8) alloys. The wheel surface speeds selected for the study were 30 m/s and 40 m/s. The ribbons produced at the lower wheel surface speed (30 m/s) were continuous having relatively uniform edges compared to the ribbons produced at the higher wheel surface speed. The thickness and the width of the melt-spun ribbonsmore » ranged between ~15 and 60 μm and 500–800 μm, respectively. The x-ray diffraction spectra of the melt-spun ribbons indicated the presence of disordered α-phase, irrespective of the composition, and the wheel surface speed. The lattice parameter decreased gradually as a function of increasing silicon content from ~0.2862 nm (Fe-3 wt.% Si) to ~0.2847 nm (Fe-8 wt.% Si). The wheel surface speed showed an insignificant effect on M S while increased silicon content resulted in a decreasing trend in M S. Elevated temperature evaluation of the magnetization (M-T curves at ~7.96 kA/m) in the case of Fe-3 & 5 wt.% Si alloy ribbons was distinctly different from that of the Fe-8 wt.% Si alloy ribbons. The curves of the as-prepared Fe-3 wt.% Si and Fe-5 wt.% Si alloy ribbons were irreversible while that of Fe-8 wt.% Si was reversible. The M S for any of the combinations of wheel surface speed and composition decreased monotonically with the increase in temperature (from 300 to 900 K). While H CI increased with the increase in temperature for all the wheel surface speed and composition combination, its nature of increase is distinct for Fe-8 wt.% Si alloy ribbons compared to Fe-3 & 5 wt.% Si alloys ribbons. Finally, it appears that rapidly-solidified Fe-3 wt.% Si and Fe-5 wt.% Si alloys ribbons are primarily comprised of the α phase (disordered phase) while the Fe-8 wt.% Si alloy ribbons are comprised primarily of disordered phase along with minor constituents of an ordered phase.« less

Investigation of structural and magnetic properties of rapidly-solidified iron-silicon alloys at ambient and elevated temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jayaraman, T. V.; Meka, V. M.; Jiang, X.

Here we investigated the ambient temperature structural properties (thickness, width, microstructure, and lattice parameter), and the ambient and high temperature (up to 900 K) direct current (DC) magnetic properties—saturation magnetization (M S) and intrinsic coercivity (H CI)—of rapidly-solidified (melt-spun) Fe-x wt.% Si (x = 3, 5, & 8) alloys. The wheel surface speeds selected for the study were 30 m/s and 40 m/s. The ribbons produced at the lower wheel surface speed (30 m/s) were continuous having relatively uniform edges compared to the ribbons produced at the higher wheel surface speed. The thickness and the width of the melt-spun ribbonsmore » ranged between ~15 and 60 μm and 500–800 μm, respectively. The x-ray diffraction spectra of the melt-spun ribbons indicated the presence of disordered α-phase, irrespective of the composition, and the wheel surface speed. The lattice parameter decreased gradually as a function of increasing silicon content from ~0.2862 nm (Fe-3 wt.% Si) to ~0.2847 nm (Fe-8 wt.% Si). The wheel surface speed showed an insignificant effect on M S while increased silicon content resulted in a decreasing trend in M S. Elevated temperature evaluation of the magnetization (M-T curves at ~7.96 kA/m) in the case of Fe-3 & 5 wt.% Si alloy ribbons was distinctly different from that of the Fe-8 wt.% Si alloy ribbons. The curves of the as-prepared Fe-3 wt.% Si and Fe-5 wt.% Si alloy ribbons were irreversible while that of Fe-8 wt.% Si was reversible. The M S for any of the combinations of wheel surface speed and composition decreased monotonically with the increase in temperature (from 300 to 900 K). While H CI increased with the increase in temperature for all the wheel surface speed and composition combination, its nature of increase is distinct for Fe-8 wt.% Si alloy ribbons compared to Fe-3 & 5 wt.% Si alloys ribbons. Finally, it appears that rapidly-solidified Fe-3 wt.% Si and Fe-5 wt.% Si alloys ribbons are primarily comprised of the α phase (disordered phase) while the Fe-8 wt.% Si alloy ribbons are comprised primarily of disordered phase along with minor constituents of an ordered phase.« less

HIGH ALBEDO AND ENVIRONMENT-FRIENDLY CONCRETE FOR SMART GROWTH AND SUSTAINABLE DEVELOPMENT

EPA Science Inventory

Concrete surfaces absorb heat from sunlight due to their low solar reflectivity (albedo). This increases the local ambient temperature in urban areas (the so-called "heat-island" effect). The heat-island effect leads to a waste of energy because of increased cooling costs. ...

The Snow Must Go On: Ground Ice Encasement, Snow Compaction and Absence of Snow Differently Cause Soil Hypoxia, CO2 Accumulation and Tree Seedling Damage in Boreal Forest

PubMed Central

Vuosku, Jaana; Ovaskainen, Anu; Stark, Sari; Rautio, Pasi

2016-01-01

At high latitudes, the climate has warmed at twice the rate of the global average with most changes observed in autumn, winter and spring. Increasing winter temperatures and wide temperature fluctuations are leading to more frequent rain-on-snow events and freeze-thaw cycles causing snow compaction and formation of ice layers in the snowpack, thus creating ice encasement (IE). By decreasing the snowpack insulation capacity and restricting soil-atmosphere gas exchange, modification of the snow properties may lead to colder soil but also to hypoxia and accumulation of trace gases in the subnivean environment. To test the effects of these overwintering conditions changes on plant winter survival and growth, we established a snow manipulation experiment in a coniferous forest in Northern Finland with Norway spruce and Scots pine seedlings. In addition to ambient conditions and prevention of IE, we applied three snow manipulation levels: IE created by artificial rain-on-snow events, snow compaction and complete snow removal. Snow removal led to deeper soil frost during winter, but no clear effect of IE or snow compaction done in early winter was observed on soil temperature. Hypoxia and accumulation of CO2 were highest in the IE plots but, more importantly, the duration of CO2 concentration above 5% was 17 days in IE plots compared to 0 days in ambient plots. IE was the most damaging winter condition for both species, decreasing the proportion of healthy seedlings by 47% for spruce and 76% for pine compared to ambient conditions. Seedlings in all three treatments tended to grow less than seedlings in ambient conditions but only IE had a significant effect on spruce growth. Our results demonstrate a negative impact of winter climate change on boreal forest regeneration and productivity. Changing snow conditions may thus partially mitigate the positive effect of increasing growing season temperatures on boreal forest productivity. PMID:27254100

The Snow Must Go On: Ground Ice Encasement, Snow Compaction and Absence of Snow Differently Cause Soil Hypoxia, CO2 Accumulation and Tree Seedling Damage in Boreal Forest.

PubMed

Martz, Françoise; Vuosku, Jaana; Ovaskainen, Anu; Stark, Sari; Rautio, Pasi

2016-01-01

At high latitudes, the climate has warmed at twice the rate of the global average with most changes observed in autumn, winter and spring. Increasing winter temperatures and wide temperature fluctuations are leading to more frequent rain-on-snow events and freeze-thaw cycles causing snow compaction and formation of ice layers in the snowpack, thus creating ice encasement (IE). By decreasing the snowpack insulation capacity and restricting soil-atmosphere gas exchange, modification of the snow properties may lead to colder soil but also to hypoxia and accumulation of trace gases in the subnivean environment. To test the effects of these overwintering conditions changes on plant winter survival and growth, we established a snow manipulation experiment in a coniferous forest in Northern Finland with Norway spruce and Scots pine seedlings. In addition to ambient conditions and prevention of IE, we applied three snow manipulation levels: IE created by artificial rain-on-snow events, snow compaction and complete snow removal. Snow removal led to deeper soil frost during winter, but no clear effect of IE or snow compaction done in early winter was observed on soil temperature. Hypoxia and accumulation of CO2 were highest in the IE plots but, more importantly, the duration of CO2 concentration above 5% was 17 days in IE plots compared to 0 days in ambient plots. IE was the most damaging winter condition for both species, decreasing the proportion of healthy seedlings by 47% for spruce and 76% for pine compared to ambient conditions. Seedlings in all three treatments tended to grow less than seedlings in ambient conditions but only IE had a significant effect on spruce growth. Our results demonstrate a negative impact of winter climate change on boreal forest regeneration and productivity. Changing snow conditions may thus partially mitigate the positive effect of increasing growing season temperatures on boreal forest productivity.

Influence of alkyl sulfates on waste activated sludge fermentation at ambient temperature.

PubMed

Jiang, Su; Chen, Yinguang; Zhou, Qi

2007-09-05

Alkyl sulfates (AS), such as sodium dodecyl sulfate (SDS), are widely used in household and industrial products, and can be found in some wastewater and waste activated sludge (WAS). The effect of SDS on the fermentation of WAS at ambient temperature was investigated in this paper. Experimental results showed that the concentrations of protein and carbohydrate in aqueous phase increased with the amount of SDS. The concentrations of both NH(4)(+)-N and PO(4)(3-)-P in fermentation liquor also increased in the presence of SDS. In addition, it was observed that the fermentative short-chain fatty acids (SCFAs) concentration was affected by SDS. With the increase of SDS dosage, the maximum SCFAs concentration increased, and the fermentation time before reaching the maximum SCFAs concentration also increased. Further investigation showed that the produced SCFAs consisted of acetic, propionic, n-butyric, iso-butyric, n-valeric and iso-valeric acids, and acetic, iso-valeric and propionic acids were the three main products. The influence of SDS on methanogenesis was also investigated, and the inhibitory effect of SDS on methanogens activity was observed.

Evidence for cumulative temperature as an initiating and terminating factor in downstream migratory behavior of Atlantic salmon (Salmo salar) smolts

USGS Publications Warehouse

Zydlewski, G.B.; Haro, A.; McCormick, S.D.

2005-01-01

Temperature control of Atlantic salmon (Salmo salar) smolt migration was tested using a novel technique allowing nearly continuous monitoring of behavior with complete control over environmental conditions. Parr and presmolts were implanted with passive integrated transponder tags, placed in simulated streams, and monitored for upstream and downstream movements. Beginning 18 April, temperature was increased 1??C every third day (advanced), fourth day (ambient), and tenth day (delayed). Smolt downstream movements were initially low, peaked in mid-May, and subsequently declined under all conditions. Parr downstream movements were significantly lower than those of smolts in all treatments (0.8 ?? 0.5 movement??day-1 versus 26.5 ?? 4.5 movements??day-1, mean ?? SE) and showed no increase. At delayed temperatures, smolts sustained downstream movements through July; those under ambient and advanced conditions ceased activity by mid-June. Initiation and termination of downstream movements occurred at significantly different temperatures but at the same number of degree-days in all treatments. Physiological changes associated with smolting (gill Na+,K +-ATPase activity and plasma thyroxine) were coincident with behavioral changes. This is the first evidence of a behavioral component to the smolt window. We found that temperature experience over time is more relevant to initiation and termination of downstream movement than a temperature threshold. ?? 2005 NRC Canada.

The mass and speed dependence of meteor air plasma temperatures

NASA Technical Reports Server (NTRS)

Jenniskens, Peter; Laux, Christophe O.; Wilson, Michael A.; Schaller, Emily L.

2004-01-01

The speed and mass dependence of meteor air plasma temperatures is perhaps the most important data needed to understand how small meteoroids chemically change the ambient atmosphere in their path and enrich the ablated meteoric organic matter with oxygen. Such chemistry can play an important role in creating prebiotic compounds. The excitation conditions in various air plasma emissions were measured from high-resolution optical spectra of Leonid storm meteors during NASA's Leonid Multi-Instrument Aircraft Campaign. This was the first time a sufficient number and range of temperature measurements were obtained to search for meteoroid mass and speed dependencies. We found slight increases in temperature with decreasing altitude, but otherwise nearly constant values for meteoroids with speeds between 35 and 72 km/s and masses between 10(-5) g and 1 g. We conclude that faster and more massive meteoroids produce a larger emission volume, but not a higher air plasma temperature. We speculate that the meteoric plasma may be in multiphase equilibrium with the ambient atmosphere, which could mean lower plasma temperatures in a CO(2)-rich early Earth atmosphere.

The mass and speed dependence of meteor air plasma temperatures.

PubMed

Jenniskens, Peter; Laux, Christophe O; Wilson, Michael A; Schaller, Emily L

2004-01-01

The speed and mass dependence of meteor air plasma temperatures is perhaps the most important data needed to understand how small meteoroids chemically change the ambient atmosphere in their path and enrich the ablated meteoric organic matter with oxygen. Such chemistry can play an important role in creating prebiotic compounds. The excitation conditions in various air plasma emissions were measured from high-resolution optical spectra of Leonid storm meteors during NASA's Leonid Multi-Instrument Aircraft Campaign. This was the first time a sufficient number and range of temperature measurements were obtained to search for meteoroid mass and speed dependencies. We found slight increases in temperature with decreasing altitude, but otherwise nearly constant values for meteoroids with speeds between 35 and 72 km/s and masses between 10(-5) g and 1 g. We conclude that faster and more massive meteoroids produce a larger emission volume, but not a higher air plasma temperature. We speculate that the meteoric plasma may be in multiphase equilibrium with the ambient atmosphere, which could mean lower plasma temperatures in a CO(2)-rich early Earth atmosphere.

Effects of dietary DL-2-hydroxy-4(methylthio)butanoic acid supplementation on growth performance, indices of ascites syndrome, and antioxidant capacity of broilers reared at low ambient temperature

NASA Astrophysics Data System (ADS)

Yang, G. L.; Zhang, K. Y.; Ding, X. M.; Zheng, P.; Luo, Y. H.; Bai, S. P.; Wang, J. P.; Xuan, Y.; Su, Z. W.; Zeng, Q. F.

2016-08-01

This study examined the effects of dietary DL-2-hydroxy-4(methylthio)butanoic acid (DL-HMTBA) supplementation on growth performance, antioxidant capacity, and ascites syndrome (AS) in broilers reared at low ambient temperature (LAT) from 7 to 28 days of age. Eight hundred 7-day-old broilers were randomly assigned to two ambient temperatures (LAT and normal ambient temperature [NAT]), four supplemental DL-HMTBA levels (0.17, 0.34, 0.51, and 0.68 %) of the basal diet in a 2 × 4 factorial arrangement (ten replicate pens; ten birds/pen). LAT and NAT indicate temperatures of 12-14 and 24-26 °C in two chambers, respectively, and broilers were reared at these temperatures from 7 to 28 days of age. LAT significantly decreased body weight gain ( P < 0.001), serum glutathione (GSH) content (day 14, P = 0.02; day 28, P = 0.045), glutathione peroxidase (GSH-Px) activity, and total antioxidant capacity (T-AOC) at 21 days ( P = 0.001, 0.015) and 28 days ( P = 0.017, 0.010) and increased feed conversion ratio (FCR) ( P < 0.001), serum malondialdehyde (day 21, P = 0.000) and protein carbonyl Level (day 14, P = 0.003; day 21, P = 0.035). As for incidence of AS, there were significant effects of LAT on red blood cell (RBC) count ( P < 0.05), hematocrit (HCT) ( P < 0.05), and the right to total ventricular weight ratio (RV/TV) at 21 days ( P = 0.012) and 28 days ( P = 0.046). Supplementation of DL-HMTBA markedly decreased RV/TV at day 28 ( P = 0.021), RBC (day 21, P = 0.008), HCT (day 21, P < 0.001), mean cell hemoglobin (day 14, P = 0.035; day 21, P = 0.003), and serum protein carbonyl level (day 21, P = 0.009), while significantly increased serum GSH content (day 14, P = 0.022; day 28, P = 0.001), SOD and GSH-Px activities at 21 days of age ( P < 0.001 and P = 0.037). The optimal supplemental DL-HMTBA levels in basal diet of broilers aged from 7 to 28 days under low or normal temperatures were similar, so the authors recommended supplemental of DL-HMTBA level was 0.46 %.

Alternative Refrigerant Evaluation for High-Ambient-Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar; Shrestha, Som S.; Munk, Jeffrey D.

The Oak Ridge National Laboratory (ORNL) High-Ambient-Temperature Evaluation Program for low– global warming potential (Low-GWP) Refrigerants aims to develop an understanding of the performance of low-GWP alternative refrigerants to hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high-ambient-temperature conditions. This final report describes the parties involved, the alternative refrigerant selection process, the test procedures, and the final results.

Alternative Refrigerant Evaluation for High-Ambient Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar; Munk, Jeffrey D.; Shrestha, Som S.

The Oak Ridge National Laboratory (ORNL) High-Ambient Temperature Testing Program for Low-GWP Refrigerants aims to develop an understanding of the performance of low-Global Warming Potential (low-GWP) alternatives to Hydrochlorofluorocarbon (HCFC) and Hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high ambient temperature conditions. This interim working paper describes the parties involved, the alternative refrigerants selection process, the test procedures, and the preliminary results.

Environmental impacts on the gonadotropic system in female Atlantic salmon (Salmo salar) during vitellogenesis: Photothermal effects on pituitary gonadotropins, ovarian gonadotropin receptor expression, plasma sex steroids and oocyte growth.

PubMed

Taranger, Geir Lasse; Muncaster, Simon; Norberg, Birgitta; Thorsen, Anders; Andersson, Eva

2015-09-15

The gonadotropic system and ovarian growth and development were studied during vitellogenesis in female Atlantic salmon subjected to either simulated natural photoperiod and ambient water temperature (NL-amb), or an accelerating photoperiod (short day of LD8:16 from May 10) combined with either warmed (ca 2°C above ambient; 8L-warm) or cooled water (ca 2°C below ambient; 8L-cold) from May to September. Monthly samples were collected from 10 females/group for determination of transcript levels of pituitary gonadotropin subunits (fshb and lhb) and ovarian gonadotropin receptors (fshr and lhr), plasma sex steroids (testosterone: T and estradiol-17β: E2), gonadosomatic index (GSI) and oocyte size. Short day in combination with either warmed or cooled water induced an earlier increase in pituitary fshb and lhb levels compared with NL-amb controls, and advanced ovarian growth and the seasonal profiles of T, E2. By contrast only minor effects were seen of the photothermal treatments on ovarian fshr and lhr. The 8L-cold had earlier increase in fshb, lhb and E2, but similar oocyte and gonadal growth as 8L-warm, suggesting that the 8L-cold group tried to compensate for the lower water temperature during the period of rapid gonadal growth by increasing fshb and E2 production. Both the 8L-warm and 8L-cold groups showed incomplete ovulation in a proportion of the females, possibly due to the photoperiod advancement resulting in earlier readiness of spawning occurring at a higher ambient temperature, or due to some reproductive dysfunction caused by photothermal interference with normal neuroendocrine regulation of oocyte development and maturation. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of soaking and acidification on physicochemical properties of calcium-fortified rice.

PubMed

Sirisoontaralak, Porntip; Limboon, Pailin; Jatuwong, Sujitra; Chavanalikit, Arusa

2016-06-01

Calcium-fortified rice was prepared by soaking milled rice in calcium lactate solution, steaming and drying, and physicochemical properties were determined to evaluate effects of calcium concentration (0, 30, 50 g L(-1) ), soaking temperature (ambient temperature, 40 °C, 60 °C) and acidification. Calcium-fortified rice had less lightness. More total solid loss was observed, especially at high soaking temperature. Harder texture was detected with increased calcium concentration. Calcium fortification lowered pasting viscosity of milled rice. Panelists accepted all fortified rice; however, only rice soaked at 50 g L(-1) concentration could be claimed as a good source of calcium. Increasing of soaking temperature induced more penetration of calcium to rice kernels but calcium was lost more easily after washing. With addition of acetic acid to the soaking solution, enriched calcium content was comparable to that of high soaking temperature but with better retention after washing and calcium solubility was improved. Acid induced reduction of lightness and cooked rice hardness but increased total solid loss and pasting viscosity. Although the taste of acetic acid remained, panelists still accepted the fortified rice. Calcium-fortified rice (190.47-194.3 mg 100 g(-1) ) could be successfully produced by soaking milled rice in 50 g L(-1) calcium lactate solution at 40 °C or at ambient temperature with acidification. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Tympanal spontaneous oscillations reveal mechanisms for the control of amplified frequency in tree crickets

NASA Astrophysics Data System (ADS)

Mhatre, Natasha; Robert, Daniel

2018-05-01

Tree cricket hearing shows all the features of an actively amplified auditory system, particularly spontaneous oscillations (SOs) of the tympanal membrane. As expected from an actively amplified auditory system, SO frequency and the peak frequency in evoked responses as observed in sensitivity spectra are correlated. Sensitivity spectra also show compressive non-linearity at this frequency, i.e. a reduction in peak height and sharpness with increasing stimulus amplitude. Both SO and amplified frequency also change with ambient temperature, allowing the auditory system to maintain a filter that is matched to song frequency. In tree crickets, remarkably, song frequency varies with ambient temperature. Interestingly, active amplification has been reported to be switched ON and OFF. The mechanism of this switch is as yet unknown. In order to gain insights into this switch, we recorded and analysed SOs as the auditory system transitioned from the passive (OFF) state to the active (ON) state. We found that while SO amplitude did not follow a fixed pattern, SO frequency changed during the ON-OFF transition. SOs were first detected above noise levels at low frequencies, sometimes well below the known song frequency range (0.5-1 kHz lower). SO frequency was observed to increase over the next ˜30 minutes, in the absence of any ambient temperature change, before settling at a frequency within the range of conspecific song. We examine the frequency shift in SO spectra with temperature and during the ON/OFF transition and discuss the mechanistic implications. To our knowledge, such modulation of active auditory amplification, and its dynamics are unique amongst auditory animals.

An experimental study on the thermal characteristics and heating effect of arc-fault from Cu core in residential electrical wiring fires

PubMed Central

Du, Jian-Hua; Zeng, Yi; Pan, Leng; Zhang, Ren-Cheng

2017-01-01

The characteristics of a series direct current (DC) arc-fault including both electrical and thermal parameters were investigated based on an arc-fault simulator to provide references for multi-parameter electrical fire detection method. Tests on arc fault behavior with three different initial circuit voltages, resistances and arc gaps were conducted, respectively. The influences of circuit conditions on arc dynamic image, voltage, current or power were interpreted. Also, the temperature rises of electrode surface and ambient air were studied. The results showed that, first, significant variations of arc structure and light emitting were observed under different conditions. A thin outer burning layer of vapor generated from electrodes with orange light was found due to the extremely high arc temperature. Second, with the increasing electrode gap in discharging, the arc power was shown to have a non monotonic relationship with arc length for constant initial circuit voltage and resistance. Finally, the temperature rises of electrode surface caused by heat transfer from arc were found to be not sensitive with increasing arc length due to special heat transfer mechanism. In addition, temperature of ambient air showed a large gradient in radial direction of arc. PMID:28797055

An experimental study on the thermal characteristics and heating effect of arc-fault from Cu core in residential electrical wiring fires.

PubMed

Du, Jian-Hua; Tu, Ran; Zeng, Yi; Pan, Leng; Zhang, Ren-Cheng

2017-01-01

The characteristics of a series direct current (DC) arc-fault including both electrical and thermal parameters were investigated based on an arc-fault simulator to provide references for multi-parameter electrical fire detection method. Tests on arc fault behavior with three different initial circuit voltages, resistances and arc gaps were conducted, respectively. The influences of circuit conditions on arc dynamic image, voltage, current or power were interpreted. Also, the temperature rises of electrode surface and ambient air were studied. The results showed that, first, significant variations of arc structure and light emitting were observed under different conditions. A thin outer burning layer of vapor generated from electrodes with orange light was found due to the extremely high arc temperature. Second, with the increasing electrode gap in discharging, the arc power was shown to have a non monotonic relationship with arc length for constant initial circuit voltage and resistance. Finally, the temperature rises of electrode surface caused by heat transfer from arc were found to be not sensitive with increasing arc length due to special heat transfer mechanism. In addition, temperature of ambient air showed a large gradient in radial direction of arc.

Mitigating methane emission from paddy soil with rice-straw biochar amendment under projected climate change

PubMed Central

Han, Xingguo; Sun, Xue; Wang, Cheng; Wu, Mengxiong; Dong, Da; Zhong, Ting; Thies, Janice E.; Wu, Weixiang

2016-01-01

Elevated global temperatures and increased concentrations of carbon dioxide (CO2) in the atmosphere associated with climate change will exert profound effects on rice cropping systems, particularly on their greenhouse gas emitting potential. Incorporating biochar into paddy soil has been shown previously to reduce methane (CH4) emission from paddy rice under ambient temperature and CO2. We examined the ability of rice straw-derived biochar to reduce CH4 emission from paddy soil under elevated temperature and CO2 concentrations expected in the future. Adding biochar to paddy soil reduced CH4 emission under ambient conditions and significantly reduced emissions by 39.5% (ranging from 185.4 mg kg−1 dry weight soil, dws season−1 to 112.2 mg kg−1 dws season−1) under simultaneously elevated temperature and CO2. Reduced CH4 release was mainly attributable to the decreased activity of methanogens along with the increased CH4 oxidation activity and pmoA gene abundance of methanotrophs. Our findings highlight the valuable services of biochar amendment for CH4 control from paddy soil in a future that will be shaped by climate change. PMID:27090814

High tolerance to temperature and salinity change should enable scleractinian coral Platygyra acuta from marginal environments to persist under future climate change.

PubMed

Chui, Apple Pui Yi; Ang, Put

2017-01-01

With projected changes in the marine environment under global climate change, the effects of single stressors on corals have been relatively well studied. However, more focus should be placed on the interactive effects of multiple stressors if their impacts upon corals are to be assessed more realistically. Elevation of sea surface temperature is projected under global climate change, and future increases in precipitation extremes related to the monsoon are also expected. Thus, the lowering of salinity could become a more common phenomenon and its impact on corals could be significant as extreme precipitation usually occurs during the coral spawning season. Here, we investigated the interactive effects of temperature [24, 27 (ambient), 30, 32°C] and salinity [33 psu (ambient), 30, 26, 22, 18, 14 psu] on larval settlement, post-settlement survival and early growth of the dominant coral Platygyra acuta from Hong Kong, a marginal environment for coral growth. The results indicate that elevated temperatures (+3°C and +5°C above ambient) did not have any significant effects on larval settlement success and post-settlement survival for up to 56 days of prolonged exposure. Such thermal tolerance was markedly higher than that reported in the literature for other coral species. Moreover, there was a positive effect of these elevated temperatures in reducing the negative effects of lowered salinity (26 psu) on settlement success. The enhanced settlement success brought about by elevated temperatures, together with the high post-settlement survival recorded up to 44 and 8 days of exposure under +3°C and +5°C ambient respectively, resulted in the overall positive effects of elevated temperatures on recruitment success. These results suggest that projected elevation in temperature over the next century should not pose any major problem for the recruitment success of P. acuta. The combined effects of higher temperatures and lowered salinity (26 psu) could even be beneficial. Therefore, corals that are currently present in marginal environments like Hong Kong, as exemplified by the dominant P. acuta, are likely to persist in a warmer and intermittently less saline, future ocean.

High tolerance to temperature and salinity change should enable scleractinian coral Platygyra acuta from marginal environments to persist under future climate change

PubMed Central

Chui, Apple Pui Yi; Ang, Put

2017-01-01

With projected changes in the marine environment under global climate change, the effects of single stressors on corals have been relatively well studied. However, more focus should be placed on the interactive effects of multiple stressors if their impacts upon corals are to be assessed more realistically. Elevation of sea surface temperature is projected under global climate change, and future increases in precipitation extremes related to the monsoon are also expected. Thus, the lowering of salinity could become a more common phenomenon and its impact on corals could be significant as extreme precipitation usually occurs during the coral spawning season. Here, we investigated the interactive effects of temperature [24, 27 (ambient), 30, 32°C] and salinity [33 psu (ambient), 30, 26, 22, 18, 14 psu] on larval settlement, post-settlement survival and early growth of the dominant coral Platygyra acuta from Hong Kong, a marginal environment for coral growth. The results indicate that elevated temperatures (+3°C and +5°C above ambient) did not have any significant effects on larval settlement success and post-settlement survival for up to 56 days of prolonged exposure. Such thermal tolerance was markedly higher than that reported in the literature for other coral species. Moreover, there was a positive effect of these elevated temperatures in reducing the negative effects of lowered salinity (26 psu) on settlement success. The enhanced settlement success brought about by elevated temperatures, together with the high post-settlement survival recorded up to 44 and 8 days of exposure under +3°C and +5°C ambient respectively, resulted in the overall positive effects of elevated temperatures on recruitment success. These results suggest that projected elevation in temperature over the next century should not pose any major problem for the recruitment success of P. acuta. The combined effects of higher temperatures and lowered salinity (26 psu) could even be beneficial. Therefore, corals that are currently present in marginal environments like Hong Kong, as exemplified by the dominant P. acuta, are likely to persist in a warmer and intermittently less saline, future ocean. PMID:28622371

Ambient temperature influences the neural benefits of exercise.

PubMed

Maynard, Mark E; Chung, Chasity; Comer, Ashley; Nelson, Katharine; Tran, Jamie; Werries, Nadja; Barton, Emily A; Spinetta, Michael; Leasure, J Leigh

2016-02-15

Many of the neural benefits of exercise require weeks to manifest. It would be useful to accelerate onset of exercise-driven plastic changes, such as increased hippocampal neurogenesis. Exercise represents a significant challenge to the brain because it produces heat, but brain temperature does not rise during exercise in the cold. This study tested the hypothesis that exercise in cold ambient temperature would stimulate hippocampal neurogenesis more than exercise in room or hot conditions. Adult female rats had exercise access 2h per day for 5 days at either room (20 °C), cold (4.5 °C) or hot (37.5 °C) temperature. To label dividing hippocampal precursor cells, animals received daily injections of BrdU. Brains were immunohistochemically processed for dividing cells (Ki67+), surviving cells (BrdU+) and new neurons (doublecortin, DCX) in the hippocampal dentate gyrus. Animals exercising at room temperature ran significantly farther than animals exercising in cold or hot conditions (room 1490 ± 400 m; cold 440 ± 102 m; hot 291 ± 56 m). We therefore analyzed the number of Ki67+, BrdU+ and DCX+ cells normalized for shortest distance run. Contrary to our hypothesis, exercise in either cold or hot conditions generated significantly more Ki67+, BrdU+ and DCX+ cells compared to exercise at room temperature. Thus, a limited amount of running in either cold or hot ambient conditions generates more new cells than a much greater distance run at room temperature. Taken together, our results suggest a simple means by which to augment exercise effects, yet minimize exercise time. Copyright © 2015 Elsevier B.V. All rights reserved.

Temperature effects on the deformation and fracture of Al-Li-Cu-In alloys

NASA Technical Reports Server (NTRS)

Wagner, John A.; Gangloff, Richard P.

1991-01-01

The crack initiation and growth fracture resistance of Al-Cu-Li and Al-Cu-Li-In alloys were characterized and optimized for cryogenic tank applications. Presently, the effects of stress state and temperature is being determined on the fracture toughness and fracture mechanisms of commercially available Vintage 3 2090-T81 and experimental 2090+In-T6. Precracked J-integral specimens of both alloys were tested at ambient and cryogenic temperatures in the plane stress and plane strain conditions. Considering ambient temperature, results showed that 2090-T81 exhibited the highest toughness in both plane strain and plane stress conditions. For the plane strain condition, reasonable crack initiation and growth toughness of 1090-T81 are associated with a significant amount of delamination and transgranular fracture. Plane stress toughnesses were higher and fracture was characterized by shear cracking with minimal delaminations. In comparisons, the fracture behavior of 2090+In-T6 is significantly degraded by subgrain boundary precipitation. Toughness is low and characterized by intersubgranular fracture with no delamination in the plane stress or plane strain conditions. Intersubgranular cracking is a low energy event which presumably occurs prior to the onset of slip band cracking. Copious grain boundary precipitation is atypical of commercially available 2090. At cryogenic temperatures, both alloys exhibit increased yield strength, toughness, and amount of delamination and shear cracking. The change in fracture mode of 2090+In-T6 from intersubgranular cracking at ambient temperature to a combination of intersubgranular cracking, shear cracking, and delamination at cryogenic temperature is the subject of further investigation.

Evaluation of contact heat thermal threshold testing for standardized assessment of cutaneous nociception in horses - comparison of different locations and environmental conditions

PubMed Central

2013-01-01

Background The aim of the study was to evaluate the performance of contact heat thermal stimulation in horses at different body sites and under different environmental conditions and different test situations. Five warm-blood horses were equipped with the thermal probe located on the skin of nostril (N), withers (W) or coronary band (C). Skin temperature and reaction temperature (thermal threshold) at each location were measured and percent thermal excursion (% TE = 100 * (threshold temperature - skin temperature)/(cut-out temperature - skin temperature) was calculated. Environmental conditions were changed in partial random order for all locations, so each horse was tested in its familiar box stall and stocks, in the morning and evening and at warm and cold ambient temperatures. Type of reaction to the stimulus and horse’s general behaviour during stimulation were recorded. The stimulation sites were examined for the occurrence of possible skin lesions. Results Skin temperatures were significantly different during warm and cold ambient temperatures at all three locations, but remained constant over repeated stimulation. An obvious response to stimulation before reaching cut-out temperature could be detected most frequently at N and W in boxes during warm ambient temperatures. The most frequent type of reaction to thermal stimulation at the nostril was headshaking (64.6%), skin twitching at the withers (82.9%) and hoof withdrawal at the coronary band (79.2%). Conclusion The outcome of thermal threshold testing depended on ambient temperature, stimulation site and environment. Best results with the WTT2 in horses were obtained at the nostrils or withers in a familiar environment at warm ambient temperatures. PMID:23298405

Evaluation of contact heat thermal threshold testing for standardized assessment of cutaneous nociception in horses - comparison of different locations and environmental conditions.

PubMed

Poller, Christin; Hopster, Klaus; Rohn, Karl; Kästner, Sabine Br

2013-01-08

The aim of the study was to evaluate the performance of contact heat thermal stimulation in horses at different body sites and under different environmental conditions and different test situations. Five warm-blood horses were equipped with the thermal probe located on the skin of nostril (N), withers (W) or coronary band (C). Skin temperature and reaction temperature (thermal threshold) at each location were measured and percent thermal excursion (% TE = 100 * (threshold temperature - skin temperature)/(cut-out temperature - skin temperature) was calculated. Environmental conditions were changed in partial random order for all locations, so each horse was tested in its familiar box stall and stocks, in the morning and evening and at warm and cold ambient temperatures. Type of reaction to the stimulus and horse's general behaviour during stimulation were recorded. The stimulation sites were examined for the occurrence of possible skin lesions. Skin temperatures were significantly different during warm and cold ambient temperatures at all three locations, but remained constant over repeated stimulation. An obvious response to stimulation before reaching cut-out temperature could be detected most frequently at N and W in boxes during warm ambient temperatures. The most frequent type of reaction to thermal stimulation at the nostril was headshaking (64.6%), skin twitching at the withers (82.9%) and hoof withdrawal at the coronary band (79.2%). The outcome of thermal threshold testing depended on ambient temperature, stimulation site and environment. Best results with the WTT2 in horses were obtained at the nostrils or withers in a familiar environment at warm ambient temperatures.

Review: Testicular vascular cone development and its association with scrotal thermoregulation, semen quality and sperm production in bulls.

PubMed

Kastelic, J P; Rizzoto, G; Thundathil, J

2018-06-01

Several structural and functional features keep bull testes 2°C to 6°C below body temperature, essential for the production of morphologically normal, motile and fertile sperm. The testicular vascular cone (TVC), located above the testis, consists of a highly coiled testicular artery surrounded by a complex network of small veins (pampiniform plexus). The TVC functions as a counter-current heat exchanger to transfer heat from the testicular artery to the testicular vein, cooling blood before it enters the testis. Bulls with increased TVC diameter or decreased distance between arterial and venous blood, have a greater percentage of morphologically normal sperm. Both the scrotum and testes are warmest at the origin of their blood supply (top of scrotum and bottom of testis), but they are cooler distal to that point. In situ, these opposing temperature gradients result in a nearly uniform testicular temperature (top to bottom), cooler than body temperature. The major source of testicular heat is blood flow, not testicular metabolism. High ambient temperatures have less deleterious effects on spermatogenesis in Bos indicus v. Bos taurus bulls; differences in TVC morphology in B. indicus bulls confer a better testicular blood supply and promote heat transfer. There is a long-standing paradigm that testes operate on the brink of hypoxia, increased testicular temperature does not increase blood flow, and the resulting hypoxia reduces morphologically normal and motile sperm following testicular hyperthermia. However, in recent studies in rams, either systemic hypoxia or increased testicular temperature increased testicular blood flow and there were sufficient increases in oxygen uptake to prevent tissue hypoxia. Therefore, effects of increased testicular temperature were attributed to testicular temperature per se and not to secondary hypoxia. There are many causes of increased testicular temperature, including high ambient temperatures, fever, increased recumbency, high-energy diets, or experimental insulation of the scrotum or the scrotal neck. It is well known that increased testicular temperatures have adverse effects on spermatogenesis. Heat affects all germ cells and all stages of spermatogenesis, with substantial increases in temperature and/or extended intervals of increased testicular temperature having the most profound effects. Increased testicular temperature has adverse effects on percentages of motile, live and morphologically normal sperm. In particular, increased testicular temperature increases the percentage of sperm with abnormal morphology, particularly head defects. Despite differences among bulls in the kind and percentage of abnormal sperm, the interval from increased testicular temperature to the emergence of specific sperm defects is consistent and predictable. Scrotal surface temperatures and structural characteristics of the testis and TVC can be assessed with IR thermography and ultrasonography, respectively.

The association between ambient temperature and childhood asthma: a systematic review

NASA Astrophysics Data System (ADS)

Xu, Zhiwei; Crooks, James Lewis; Davies, Janet Mary; Khan, Al Fazal; Hu, Wenbiao; Tong, Shilu

2018-03-01

The objectives of this study are to review available information on the association between ambient temperature and childhood asthma, and to elucidate the possible underlying mechanisms of this relationship. A systematic review was conducted based on the papers retrieved from four databases, including PubMed, ProQuest, ScienceDirect, and Scopus. Papers examining the association of absolute temperature or temperature variation with childhood asthma published from 1 January 2000 to 31 December 2016 were included. Thirteen papers have quantified the effect of absolute temperature on childhood asthma, and six papers have examined the effect of intra- or inter-day temperature variation on childhood asthma. All studies were conducted in urban areas. Aeroallergen sensitizations were only considered in the analyses of one study. Discrepancy existed in the significance of the relationship between absolute temperature and childhood asthma, and also in the shape of this relationship (i.e. linear or non-linear) and whether temperature effects were lagged. Increasing evidence is suggesting non-linear relationship between absolute temperature and childhood asthma. Future research should investigate the burden of childhood asthma specifically attributable to extreme temperatures and temperature variation using advanced statistical approach, particularly in rural areas, after properly considering aeroallergens and air pollution. Projecting future burden of childhood asthma under climate change scenarios is also warranted.

The association between ambient temperature and childhood asthma: a systematic review.

PubMed

Xu, Zhiwei; Crooks, James Lewis; Davies, Janet Mary; Khan, Al Fazal; Hu, Wenbiao; Tong, Shilu

2018-03-01

The objectives of this study are to review available information on the association between ambient temperature and childhood asthma, and to elucidate the possible underlying mechanisms of this relationship. A systematic review was conducted based on the papers retrieved from four databases, including PubMed, ProQuest, ScienceDirect, and Scopus. Papers examining the association of absolute temperature or temperature variation with childhood asthma published from 1 January 2000 to 31 December 2016 were included. Thirteen papers have quantified the effect of absolute temperature on childhood asthma, and six papers have examined the effect of intra- or inter-day temperature variation on childhood asthma. All studies were conducted in urban areas. Aeroallergen sensitizations were only considered in the analyses of one study. Discrepancy existed in the significance of the relationship between absolute temperature and childhood asthma, and also in the shape of this relationship (i.e. linear or non-linear) and whether temperature effects were lagged. Increasing evidence is suggesting non-linear relationship between absolute temperature and childhood asthma. Future research should investigate the burden of childhood asthma specifically attributable to extreme temperatures and temperature variation using advanced statistical approach, particularly in rural areas, after properly considering aeroallergens and air pollution. Projecting future burden of childhood asthma under climate change scenarios is also warranted.

Large format lithium ion pouch cell full thermal characterisation for improved electric vehicle thermal management

NASA Astrophysics Data System (ADS)

Grandjean, Thomas; Barai, Anup; Hosseinzadeh, Elham; Guo, Yue; McGordon, Andrew; Marco, James

2017-08-01

It is crucial to maintain temperature homogeneity in lithium ion batteries in order to prevent adverse voltage distributions and differential ageing within the cell. As such, the thermal behaviour of a large-format 20 Ah lithium iron phosphate pouch cell is investigated over a wide range of ambient temperatures and C rates during both charging and discharging. Whilst previous studies have only considered one surface, this article presents experimental results, which characterise both surfaces of the cell exposed to similar thermal media and boundary conditions, allowing for thermal gradients in-plane and perpendicular to the stack to be quantified. Temperature gradients, caused by self-heating, are found to increase with increasing C rate and decreasing temperature to such an extent that 13.4 ± 0.7% capacity can be extracted using a 10C discharge compared to a 0.5C discharge, both at -10 °C ambient temperature. The former condition causes an 18.8 ± 1.1 °C in plane gradient and a 19.7 ± 0.8 °C thermal gradient perpendicular to the stack, which results in large current density distributions and local state of charge differences within the cell. The implications of these thermal and electrical inhomogeneities on ageing and battery pack design for the automotive industry are discussed.

Cloacal evaporative cooling: a previously undescribed means of increasing evaporative water loss at higher temperatures in a desert ectotherm, the Gila monster Heloderma suspectum.

PubMed

DeNardo, Dale F; Zubal, Tricia E; Hoffman, Ty C M

2004-02-01

The Gila monster Heloderma suspectum is an active forager in an environment that, at times, can be extremely hot and arid. Thus, Gila monsters face extreme thermostatic and hydrostatic demands. For a desert ectotherm routinely risking dehydration, evaporative water loss (EWL) is typically viewed as detrimental. Yet evaporation simultaneously dehydrates and cools an animal. We explored EWL in Gila monsters by measuring cutaneous, ventilatory and cloacal EWL at five ambient temperatures between 20.5 degrees C and 40 degrees C. Our results show that Gila monsters have high EWL rates relative to body mass. Cutaneous EWL underwent a consistent, temperature-dependent increase over the entire range of test temperatures (Q(10)=1.61, with EWL ranging from 0.378 to 0.954 mg g(-1) h(-1)). Ventilatory EWL did not show a significant temperature-dependent response, but ranged from 0.304 to 0.663 mg g(-1) h(-1). Cloacal EWL was extremely low and relatively constant between 20.5 degrees C and 35 degrees C, but rose dramatically above 35 degrees C (Q(10) >8.3 x 10(7), from 0.0008 at 35 degrees C to 7.30 mg g(-1) h(-1) at 40 degrees C). This steep rise in cloacal EWL coincided with an increasing suppression of body temperature relative to ambient temperature. Dehydration to 80% of initial body mass led to a delay in the onset and an attenuation of the dramatic increase in cloacal EWL. These results emphasize the potential value of EWL for thermoregulation in ectotherms and demonstrate for the first time the role of the cloaca in this process.

Ambient Dried Aerogels

NASA Technical Reports Server (NTRS)

Jones, Steven M.; Paik, Jong-Ah

2013-01-01

A method has been developed for creating aerogel using normal pressure and ambient temperatures. All spacecraft, satellites, and landers require the use of thermal insulation due to the extreme environments encountered in space and on extraterrestrial bodies. Ambient dried aerogels introduce the possibility of using aerogel as thermal insulation in a wide variety of instances where supercritically dried aerogels cannot be used. More specifically, thermoelectric devices can use ambient dried aerogel, where the advantages are in situ production using the cast-in ability of an aerogel. Previously, aerogels required supercritical conditions (high temperature and high pressure) to be dried. Ambient dried aerogels can be dried at room temperature and pressure. This allows many materials, such as plastics and certain metal alloys that cannot survive supercritical conditions, to be directly immersed in liquid aerogel precursor and then encapsulated in the final, dried aerogel. Additionally, the metalized Mylar films that could not survive the previous methods of making aerogels can survive the ambient drying technique, thus making multilayer insulation (MLI) materials possible. This results in lighter insulation material as well. Because this innovation does not require high-temperature or high-pressure drying, ambient dried aerogels are much less expensive to produce. The equipment needed to conduct supercritical drying costs many tens of thousands of dollars, and has associated running expenses for power, pressurized gasses, and maintenance. The ambient drying process also expands the size of the pieces of aerogel that can be made because a high-temperature, high-pressure system typically has internal dimensions of up to 30 cm in diameter and 60 cm in height. In the case of this innovation, the only limitation on the size of the aerogels produced would be in the ability of the solvent in the wet gel to escape from the gel network.

Association between Daily Hospital Outpatient Visits for Accidents and Daily Ambient Air Temperatures in an Industrial City.

PubMed

Chau, Tang-Tat; Wang, Kuo-Ying

2016-01-01

An accident is an unwanted hazard to a person. However, accidents occur. In this work, we search for correlations between daily accident rates and environmental factors. To study daily hospital outpatients who were admitted for accidents during a 5-year period, 2007-2011, we analyzed data regarding 168,366 outpatients using univariate regression models; we also used multivariable regression models to account for confounding factors. Our analysis indicates that the number of male outpatients admitted for accidents was approximately 1.31 to 1.47 times the number of female outpatients (P < 0.0001). Of the 12 parameters (regarding air pollution and meteorology) considered, only daily temperature exhibited consistent and significant correlations with the daily number of hospital outpatient visits for accidents throughout the 5-year analysis period. The univariate regression models indicate that older people (greater than 66 years old) had the fewest accidents per 1-degree increase in temperature, followed by young people (0-15 years old). Middle-aged people (16-65 years old) were the group of outpatients that were more prone to accidents, with an increase in accident rates of 0.8-1.2 accidents per degree increase in temperature. The multivariable regression models also reveal that the temperature variation was the dominant factor in determining the daily number of outpatient visits for accidents. Our further multivariable model analysis of temperature with respect to air pollution variables show that, through the increases in emissions and concentrations of CO, photochemical O3 production and NO2 loss in the ambient air, increases in vehicular emissions are associated with increases in temperatures. As such, increases in hospital visits for accidents are related to vehicular emissions and usage. This finding is consistent with clinical experience which shows about 60% to 80% of accidents are related to traffic, followed by accidents occurred in work place.

Association between Daily Hospital Outpatient Visits for Accidents and Daily Ambient Air Temperatures in an Industrial City

PubMed Central

Chau, Tang-Tat; Wang, Kuo-Ying

2016-01-01

An accident is an unwanted hazard to a person. However, accidents occur. In this work, we search for correlations between daily accident rates and environmental factors. To study daily hospital outpatients who were admitted for accidents during a 5-year period, 2007–2011, we analyzed data regarding 168,366 outpatients using univariate regression models; we also used multivariable regression models to account for confounding factors. Our analysis indicates that the number of male outpatients admitted for accidents was approximately 1.31 to 1.47 times the number of female outpatients (P < 0.0001). Of the 12 parameters (regarding air pollution and meteorology) considered, only daily temperature exhibited consistent and significant correlations with the daily number of hospital outpatient visits for accidents throughout the 5-year analysis period. The univariate regression models indicate that older people (greater than 66 years old) had the fewest accidents per 1-degree increase in temperature, followed by young people (0–15 years old). Middle-aged people (16–65 years old) were the group of outpatients that were more prone to accidents, with an increase in accident rates of 0.8–1.2 accidents per degree increase in temperature. The multivariable regression models also reveal that the temperature variation was the dominant factor in determining the daily number of outpatient visits for accidents. Our further multivariable model analysis of temperature with respect to air pollution variables show that, through the increases in emissions and concentrations of CO, photochemical O3 production and NO2 loss in the ambient air, increases in vehicular emissions are associated with increases in temperatures. As such, increases in hospital visits for accidents are related to vehicular emissions and usage. This finding is consistent with clinical experience which shows about 60% to 80% of accidents are related to traffic, followed by accidents occurred in work place. PMID:26815039

Labile and recalcitrant organic matter utilization by river biofilm under increasing water temperature.

PubMed

Ylla, Irene; Romaní, Anna M; Sabater, Sergi

2012-10-01

Microbial biofilms in rivers contribute to the decomposition of the available organic matter which typically shows changes in composition and bioavailability due to their origin, seasonality, and watershed characteristics. In the context of global warming, enhanced biofilm organic matter decomposition would be expected but this effect could be specific when either a labile or a recalcitrant organic matter source would be available. A laboratory experiment was performed to mimic the effect of the predicted increase in river water temperature (+4 °C above an ambient temperature) on the microbial biofilm under differential organic matter sources. The biofilm microbial community responded to higher water temperature by increasing bacterial cell number, respiratory activity (electron transport system) and microbial extracellular enzymes (extracellular enzyme activity). At higher temperature, the phenol oxidase enzyme explained a large fraction of respiratory activity variation suggesting an enhanced microbial use of degradation products from humic substances. The decomposition of hemicellulose (β-xylosidase activity) seemed to be also favored by warmer conditions. However, at ambient temperature, the enzymes highly responsible for respiration activity variation were β-glucosidase and leu-aminopeptidase, suggesting an enhanced microbial use of polysaccharides and peptides degradation products. The addition of labile dissolved organic carbon (DOC; dipeptide plus cellobiose) caused a further augmentation of heterotrophic biomass and respiratory activity. The changes in the fluorescence index and the ratio Abs(250)/total DOC indicated that higher temperature accelerated the rates of DOC degradation. The experiment showed that the more bioavailable organic matter was rapidly cycled irrespective of higher temperature while degradation of recalcitrant substances was enhanced by warming. Thus, pulses of carbon at higher water temperature might have consequences for DOC processing.

Noncontacting acoustics-based temperature measurement techniques in rapid thermal processing

NASA Astrophysics Data System (ADS)

Lee, Yong J.; Chou, Ching-Hua; Khuri-Yakub, Butrus T.; Saraswat, Krishna C.

1991-04-01

Temperature measurement of silicon wafers based on the temperature dependence of acoustic waves is studied. The change in the temperature-dependent dispersion relations of the plate modes through the wafer can be exploited to provide a viable temperature monitoring scheme with advantages over both thermocouples and pyrometers. Velocity measurements of acoustic waves through a thin layer of ambient directly above the wafer provides the temperature of the wafer-ambient interface. 1.

40 CFR 1066.105 - Ambient controls and vehicle cooling fans.

Code of Federal Regulations, 2014 CFR

2014-07-01

... range of ambient temperature and humidity. Use good engineering judgment to maintain relatively uniform temperatures throughout the test cell before testing. You are generally not required to maintain uniform temperatures throughout the test cell while the vehicle is running due to the heat generated by the vehicle...

Evaluation of 25-Percent ATJ Fuel Blends in the John Deere 4045HF 280 Engine

DTIC Science & Technology

2014-08-01

25% ATJ Blend ........ 26 Figure 16 . THC Emissions, Pre-Test, Ambient Temperature ...................................................... 28 Figure...17 . THC Emissions, Pre-Test, Desert Temperature ......................................................... 28 Figure 18 . NOx Emissions, Pre-Test...Emissions, Pre-Test, Desert Temperature (Scaled) ............................................. 32 Figure 23 . THC Emissions, Post-Test, Ambient

THERMOREGULATION AT A HIGH AMBIENT TEMPERATURE FOLLOWING THE ORAL ADMINISTRATION OF ETHANOL IN THE RAT

EPA Science Inventory

This study was designed to assess the thermoregulatory mechanisms responsible for the elevation in body temperature following ethanol administration when exposed to a high ambient temperature (Ta). ale rats of the Fischer 344 strain were gavaged with 20% ethanol at doses of 0, 2....

Resistivity of a simple metal from room temperature to 10 to the 6th K

NASA Astrophysics Data System (ADS)

Milchberg, H. M.; Freeman, R. R.; Davey, S. C.; More, R. M.

1988-11-01

The resistivity of nearly solid-density Al was measured as a function of temperature over 4 orders of magnitude above ambient by observing the self-reflection of an intense, less than 0.5 psec, 308-nm light pulse incident on a planar Al target. As an increasing function of electron temperature, the resistivity is observed initially to increase, reach a maximum which is relatively constant over an extended temperature range, and then decrease at the highest temperatures. The broad maximum is interpreted as resistivity saturation, a condition in which the mean free path of the conduction electrons reaches a minimum value as a function of temperature, regardless of the extent of any further disorder in the material.

Generation of volatile compounds in litchi wine during winemaking and short-term bottle storage.

PubMed

Wu, Yuwen; Zhu, Baoqing; Tu, Cui; Duan, Changqing; Pan, Qiuhong

2011-05-11

Evolution of volatile components during litchi (Litchi chinensis Sonn.) winemaking was monitored, and aroma profiles of litchi wines bottle aged for 5 months at ambient temperature (25-28 °C) and low temperature (8-10 °C) were compared via headspace solid phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS). The majority of terpenoids deriving from litchi juice decreased, even disappeared along with alcoholic fermentation, while terpenol oxides, ethers, and acetates came into being and increased. Ethyl octanote, isoamyl acetate, ethyl hexanoate, ethyl butanoate, cis-rose oxide, and trans-rose oxide had the highest odor activity values (OAVs) in young litchi wines. Six aromatic series were obtained by grouping OAVs of odor-active compounds with similar odor descriptions to establish the aroma profile for young litchi wines, and floral and fruity attributes were two major aroma series. Compared to ambient temperature when bottle aging, lower temperature benefited key aroma retention and expectantly extended the shelf life of young litchi wines.

Numerical Calculation and Exergy Equations of Spray Heat Exchanger Attached to a Main Fan Diffuser

NASA Astrophysics Data System (ADS)

Cui, H.; Wang, H.; Chen, S.

2015-04-01

In the present study, the energy depreciation rule of spray heat exchanger, which is attached to a main fan diffuser, is analyzed based on the second law of thermodynamics. Firstly, the exergy equations of the exchanger are deduced. The equations are numerically calculated by the fourth-order Runge-Kutta method, and the exergy destruction is quantitatively effected by the exchanger structure parameters, working fluid (polluted air, i.e., PA; sprayed water, i.e., SW) initial state parameters and the ambient reference parameters. The results are showed: (1) heat transfer is given priority to latent transfer at the bottom of the exchanger, and heat transfer of convection and is equivalent to that of condensation in the upper. (2) With the decrease of initial temperature of SW droplet, the decrease of PA velocity or the ambient reference temperature, and with the increase of a SW droplet size or initial PA temperature, exergy destruction both increase. (3) The exergy efficiency of the exchanger is 72.1 %. An approach to analyze the energy potential of the exchanger may be provided for engineering designs.

Photosynthesis, Transpiration, Leaf Temperature, and Stomatal Activity of Cotton Plants under Varying Water Potentials

PubMed Central

Pallas, J. E.; Michel, B. E.; Harris, D. G.

1967-01-01

Cotton plants, Gossypium hirsutum L. were grown in a growth room under incident radiation levels of 65, 35, and 17 Langleys per hour to determine the effects of vapor pressure deficits (VPD's) of 2, 9, and 17 mm Hg at high soil water potential, and the effects of decreasing soil water potential and reirrigation on transpiration, leaf temperature, stomatal activity, photosynthesis, and respiration at a VPD of 9 mm Hg. Transpiration was positively correlated with radiation level, air VPD and soil water potential. Reirrigation following stress led to slow recovery, which may be related to root damage occurring during stress. Leaf water potential decreased with, but not as fast as, soil water potential. Leaf temperature was usually positively correlated with light intensity and negatively correlated with transpiration, air VPD, and soil water. At high soil water, leaf temperatures ranged from a fraction of 1 to a few degrees above ambient, except at medium and low light and a VPD of 19 mm Hg when they were slightly below ambient, probably because of increased transpirational cooling. During low soil water leaf temperatures as high as 3.4° above ambient were recorded. Reirrigation reduced leaf temperature before appreciably increasing transpiration. The upper leaf surface tended to be warmer than the lower at the beginning of the day and when soil water was adequate; otherwise there was little difference or the lower surface was warmer. This pattern seemed to reflect transpiration cooling and leaf position effects. Although stomata were more numerous in the lower than the upper epidermis, most of the time a greater percentage of the upper were open. With sufficient soil water present, stomata opened with light and closed with darkness. Fewer stomata opened under low than high light intensity and under even moderate, as compared with high soil water. It required several days following reirrigation for stomata to regain original activity levels. Apparent photosynthesis of cotton leaves occasionally oscillated with variable amplitude and frequency. When soil water was adequate, photosynthesis was nearly proportional to light intensity, with some indication of higher rates at higher VPD's. As soil water decreased, photosynthesis first increased and then markedly decreased. Following reirrigation, photosynthesis rapidly recovered. Respiration was slowed moderately by decreasing soil water but increased before watering. Respiration slowed with increasing leaf age only on leaves that were previously under high light intensity. PMID:16656488

Characterization of air temperature in modern ion chambers due to phantom geometry and ambient temperature changes.

PubMed

Saenz, Daniel L; Kirby, Neil; Gutiérrez, Alonso N

2016-07-01

Temperature and pressure corrections are necessary to account for the varying mass of air in the sensitive volume of a vented ionization chamber (IC) when performing absolute dose measurements. Locations commonly used to measure the presumed IC air temperature may not accurately represent the chamber cavity air temperature, and phantoms undergoing temperature changes further compound the problem. Prior studies have characterized thermal equilibrium in separate phantoms for Farmer chambers alone. However, the purpose of this study was to characterize the cavity air temperature dependence on changes in the ambient temperature and phantom geometry configuration for a wider and more modern variety of chambers to determine if previously published wait times apply to these chambers as well. Thermal conduction properties were experimentally investigated by modifying a PTW 0.3 cm(3) Semiflex IC with a thermocouple replacing the central electrode. Air cavity temperature versus time was recorded in three phantom geometries characteristic of common absolute dose measurements. The phantoms were (15 ± 1) °C before measurement with an IC at the treatment vault temperature of (21 ± 1) °C. Simulations were conducted to provide a theoretical basis for the measurements and to simulate temperature response of a PTW PinPoint® and Farmer chamber. The simulation methods were first validated by comparison with measured Semiflex chamber thermal response curves before extension to the other chambers. Two thermal equilibria curves were recorded on different time scales. IC temperature initially dropped to the colder phantom temperature but subsequently increased as the phantom itself equilibrated with the warmer room temperature. In a large phantom of dimensions (25.5 × 25.5 × 23.4) cm(3), 3 min was required before the IC temperature reached within 0.5 °C of its equilibrium within the phantom. Similarly, wait times of 2 min were needed for 7.5 and 2 cm slab phantoms. Recording of temperature in the phantom was deemed far more accurate than measurement in ambient air due to the air cavity thermally equilibrating with phantom temperature instead of the vented ambient air. Wait times of 3 and 2 min are needed for a cube and 7.5 cm slab phantom, respectively, to achieve 0.2% dosimetric accuracy (temperature accuracy of 0.5 °C). Chamber volume alone did not determine wait times, as a 0.3 cm(3) IC required a longer wait time than a Farmer chamber, suggesting wall thickness as an important variable as well.

Elevated temperature enhances normal early embryonic development in the coral Platygyra acuta under low salinity conditions

NASA Astrophysics Data System (ADS)

Chui, Apple Pui Yi; Ang, Put

2015-06-01

To better understand the possible consequences of climate change on reef building scleractinian corals in a marginal environment, laboratory experiments were conducted to examine the interactive effects of changes in salinity and temperature on percent fertilization success and early embryonic development of the coral Platygyra acuta. In the present study, a salinity of 24 psu (ambient 32 psu) reduced fertilization success by 60 %. Normal embryonic development was reduced by >80 % at 26 psu (ambient 33 psu) with 100 % abnormal development at 22 psu under ambient temperature. Elevated temperature (+3 °C) above the ambient spawning temperature did not show any negative effects on fertilization success. However, there was a trend for more abnormal embryos to develop at elevated temperature in the 2 d of the spawning event. The interactive effects between salinity and temperature are statistically significant only on normal embryonic development of P. acuta, but not on its fertilization success. Salinity was revealed to be the main factor affecting both fertilization success and normal embryonic development. Interestingly, the much lower fertilization success (76 %) observed in the second day of spawning (Trial 2) under ambient temperature recovered to 99 % success under elevated (+3 °C) temperature conditions. Moreover, elevated temperature enhanced normal early embryonic development under lowered salinity (26 psu). This antagonistic interactive effect was consistently observed in two successive nights of spawning. Overall, our results indicate that, in terms of its fertilization success and embryonic development, P. acuta is the most tolerant coral species to reduced salinity thus far reported in the literature. Elevated temperature, at least that within the tolerable range of the corals, could apparently alleviate the potential negative effects from salinity stresses. This mitigating role of elevated temperature appears not to have been reported on corals before.

Importance of turbulence-chemistry interactions at low temperature engine conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kundu, Prithwish; Ameen, Muhsin M.; Som, Sibendu

The role of turbulence-chemistry interaction in autoignition and flame stabilization is investigated for spray flames at low temperature combustion (LTC) conditions by performing high-fidelity three-dimensional computational fluid dynamics (CFD) simulations. A recently developed Tabulated Flamelet Model (TFM) is coupled with a large eddy simulation (LES) framework and validated across a range of Engine Combustion Network (ECN) ambient temperature conditions for n-dodecane fuel. High resolution grids with 0.0625 mm minimum cell size and 25 million total cell count are implemented using adaptive mesh refinement over the spray and combustion regions. Simulations with these grids and multiple LES realizations, with a 103more » species n-dodecane mechanism show good agreement with experimental data for all the ambient conditions investigated. This modeling approach with the computational cost advantage of tabulated chemistry is then extended towards understanding the auto-ignition and flame stabilization at an ambient temperature of 750 K. These low temperature conditions lead to substantially higher ignition delays and flame liftoff lengths, and significantly leaner combustion compared to conventional high temperature diesel combustion. These conditions also require the simulations to span significantly larger temporal and spatial dimensions thereby increasing the computational cost. The TFM approach is able to capture autoignition and flame liftoff length at the low temperature conditions. Significant differences with respect to mixing, species formation and flame stabilization are observed under low temperature compared to conventional diesel combustion. At higher ambient temperatures, formation of formaldehyde is observed in the rich region (phi > 1) followed by the formation of OH in the stoichiometric regions. Under low temperature conditions, formaldehyde is observed to form at leaner regions followed by the onset of OH formation in significantly lean regions of the flame. Qualitative differences between species formation and transient flame development for the high and low temperature conditions are presented. The two stage ignition process is further investigated by studying the species formation in mixture fraction space by solving 1D flamelet equations for different scalar dissipation rates and homogeneous reactor assumption. Results show that scalar dissipation causes these radicals to diffuse within the mixture fraction space. As a result, this significantly enhances ignition and plays a dominant role at such low temperature conditions which cannot be captured by the homogeneous reaction assumption based model.« less

Importance of turbulence-chemistry interactions at low temperature engine conditions

DOE PAGES

Kundu, Prithwish; Ameen, Muhsin M.; Som, Sibendu

2017-06-08

The role of turbulence-chemistry interaction in autoignition and flame stabilization is investigated for spray flames at low temperature combustion (LTC) conditions by performing high-fidelity three-dimensional computational fluid dynamics (CFD) simulations. A recently developed Tabulated Flamelet Model (TFM) is coupled with a large eddy simulation (LES) framework and validated across a range of Engine Combustion Network (ECN) ambient temperature conditions for n-dodecane fuel. High resolution grids with 0.0625 mm minimum cell size and 25 million total cell count are implemented using adaptive mesh refinement over the spray and combustion regions. Simulations with these grids and multiple LES realizations, with a 103more » species n-dodecane mechanism show good agreement with experimental data for all the ambient conditions investigated. This modeling approach with the computational cost advantage of tabulated chemistry is then extended towards understanding the auto-ignition and flame stabilization at an ambient temperature of 750 K. These low temperature conditions lead to substantially higher ignition delays and flame liftoff lengths, and significantly leaner combustion compared to conventional high temperature diesel combustion. These conditions also require the simulations to span significantly larger temporal and spatial dimensions thereby increasing the computational cost. The TFM approach is able to capture autoignition and flame liftoff length at the low temperature conditions. Significant differences with respect to mixing, species formation and flame stabilization are observed under low temperature compared to conventional diesel combustion. At higher ambient temperatures, formation of formaldehyde is observed in the rich region (phi > 1) followed by the formation of OH in the stoichiometric regions. Under low temperature conditions, formaldehyde is observed to form at leaner regions followed by the onset of OH formation in significantly lean regions of the flame. Qualitative differences between species formation and transient flame development for the high and low temperature conditions are presented. The two stage ignition process is further investigated by studying the species formation in mixture fraction space by solving 1D flamelet equations for different scalar dissipation rates and homogeneous reactor assumption. Results show that scalar dissipation causes these radicals to diffuse within the mixture fraction space. As a result, this significantly enhances ignition and plays a dominant role at such low temperature conditions which cannot be captured by the homogeneous reaction assumption based model.« less

Maternal exposure to ambient air temperature during pregnancy and early childhood pneumonia.

PubMed

Miao, Yufeng; Shen, Yong-Ming; Lu, Chan; Zeng, Ji; Deng, Qihong

2017-10-01

Pneumonia has been widely recognized as the leading cause of death in children worldwide, but its etiology still remains unclear. We examined the association between maternal exposure to ambient air temperature during pregnancy and lifetime pneumonia in the offspring. We conducted a cohort study of 2598 preschool children aged 3-6 years in Changsha, China. The lifetime prevalence of pneumonia was assessed using questionnaire. We backwards estimated each child's exposure to air temperature during prenatal and postnatal periods. Multiple regression model was used to examine the association between childhood pneumonia and exposure to air temperature in terms of odd ratios (OR) and 95% confidence interval (CI). Prevalence of childhood pneumonia in Changsha was high up to 38.6%. We found that childhood pneumonia was significantly associated with prenatal exposure to air temperature, with adjusted OR (95% CI) = 1.77 (1.23-2.54) for an interquartile range (IQR) increase in temperature, particularly during the second trimester with adjusted OR (95% CI) = 2.26 (1.32-3.89). Boys are more susceptible to the risk of pneumonia due to air temperature than girls. We further observed that maternal exposure to extreme heat days during pregnancy increased the risk of pneumonia in the offspring. Maternal exposure to air temperature during pregnancy, particularly the second trimester, was associated with pneumonia in the children, providing the evidence for fetal origins of pneumonia. Copyright © 2017 Elsevier Ltd. All rights reserved.

Elongated Hypocotyl 5-Homolog (HYH) Negatively Regulates Expression of the Ambient Temperature-Responsive MicroRNA Gene MIR169

PubMed Central

Serivichyaswat, Phanu T.; Susila, Hendry; Ahn, Ji Hoon

2017-01-01

Arabidopsis microRNA169 (miR169) is an ambient temperature-responsive microRNA that plays an important role in stress responses and the floral transition. However, the transcription factors that regulate the expression of MIR169 have remained unknown. In this study, we show that Elongated Hypocotyl 5-Homolog (HYH) directly binds to the promoter of MIR169a and negatively regulates its expression. Absolute quantification identified MIR169a as the major locus producing miR169. GUS reporter assays revealed that the deletion of a 498-bp fragment (–1,505 to –1,007, relative to the major transcriptional start site) of MIR169a abolished its ambient temperature-responsive expression. DNA-affinity chromatography followed by liquid chromatography-mass spectrometry analysis identified transcription factor HYH as a trans-acting factor that binds to the 498-bp promoter fragment of pri-miR169a. Electrophoretic mobility shift assays and chromatin immunoprecipitation–quantitative PCR demonstrated that the HYH.2 protein, a predominant isoform of HYH, directly associated with a G-box-like motif in the 498-bp fragment of pri-miR169a. Higher enrichment of HYH.2 protein on the promoter region of MIR169a was seen at 23°C, consistent with the presence of more HYH.2 protein in the cell at the temperature. Transcript levels of pri-miR169a increased in hyh mutants and decreased in transgenic plants overexpressing HYH. Consistent with the negative regulation of MIR169a by HYH, the diurnal levels of HYH mRNA and pri-miR169a showed opposite patterns. Taken together, our results suggest that HYH is a transcription factor that binds to a G-box-like motif in the MIR169a promoter and negatively regulates ambient temperature-responsive expression of MIR169a at higher temperatures in Arabidopsis. PMID:29270188

Influence of environmental factors on activity patterns of Incisitermes minor (Isoptera: Kalotermitidae) in naturally infested logs.

PubMed

Lewis, Vernard R; Leighton, Shawn; Tabuchi, Robin; Baldwin, James A; Haverty, Michael I

2013-02-01

Acoustic emission (AE) activity patterns were measured from seven loquat [Eriobotrya japonica (Thunb.) Lindl.] logs, five containing live western drywood termite [Incisitermes minor (Hagen)] infestations, and two without an active drywood termite infestation. AE activity, as well as temperature, were monitored every 3 min under unrestricted ambient conditions in a small wooden building, under unrestricted ambient conditions but in constant darkness, or in a temperature-controlled cabined under constant darkness. Logs with active drywood termite infestations displayed similar diurnal cycles of AE activity that closely followed temperature with a peak of AE activity late in the afternoon (1700-1800 hours). When light was excluded from the building, a circadian pattern continued and apparently was driven by temperature. When the seven logs were kept at a relatively constant temperature (approximately 23 +/- 0.9 degrees C) and constant darkness, the pattern of activity was closely correlated with temperature, even with minimal changes in temperature. Temperature is the primary driver of activity of these drywood termites, but the effects are different when temperature is increasing or decreasing. At constant temperature, AE activity was highly correlated with the number of termites in the logs. The possible implications of these findings on our understanding of drywood termite biology and how this information may affect inspections and posttreatment evaluations are discussed.

Process Development--Tungsten Hemispheres.

DTIC Science & Technology

1980-04-01

pumping down to 25 microns before adding power to the molybdenum heating element. After 25 microns have been reached, power was applied and a temperature ...were formed in latter March, 1979. The initial discs were formed at a temperature of 750OF since Vought conducted tests showing that ductility increased...from 27.4%0 at ambient temperature to 41% at 750 0 F. The forming process planning instructions were changed from 650OF to 750 0 F. Five of the 32

Effect of Elevated Atmospheric CO2 and Temperature on Leaf Optical Properties and Chlorophyll Content in Acer saccharum (Marsh.)

NASA Technical Reports Server (NTRS)

Carter, Gregory A.; Bahadur, Raj; Norby, Richard J.

1999-01-01

Elevated atmospheric CO2 pressure and numerous causes of plant stress often result in decreased leaf chlorophyll contents and thus would be expected to alter leaf optical properties. Hypotheses that elevated carbon dioxide pressure and air temperature would alter leaf optical properties were tested for sugar maple (Acer saccharum Marsh.) in the middle of its fourth growing season under treatment. The saplings had been growing since 1994 in open-top chambers at Oak Ridge, Tennessee under the following treatments: 1) Ambient CO2 pressure and air temperature (control); 2) CO2 pressure approximately 30 Pa above ambient; 3) Air temperatures 3 C above ambient; 4) Elevated CO2 and air temperature. Spectral reflectance, transmittance, and absorptance in the visible spectrum (400-720 nm) did not change significantly (rho = 0.05) in response to any treatment compared with control values. Although reflectance, transmittance, and absorptance at 700 nm correlated strongly with leaf chlorophyll content, chlorophyll content was not altered significantly by the treatments. The lack of treatment effects on pigmentation explained the non-significant change in optical properties in the visible spectrum. Optical properties in the near-infrared (721-850 nm) were similarly unresponsive to treatment with the exception of an increased absorptance in leaves that developed under elevated air temperature alone. This response could not be explained by the data, but might have resulted from effects of air temperature on leaf internal structure. Results indicated no significant potential for detecting leaf optical responses to elevated CO2 or temperature by the remote sensing of reflected radiation in the 400-850 nm spectrum.

Influence of growth temperature on the amounts of tocopherols, tocotrienols, and gamma-oryzanol in brown rice.

PubMed

Britz, Steven J; Prasad, P V V; Moreau, Robert A; Allen, L Hartwell; Kremer, Diane F; Boote, Kenneth J

2007-09-05

Brown rice is a valuable source of lipid-soluble antioxidants including ferulated phytosterols (i.e., gamma-oryzanol), tocopherols, and tocotrienols. To evaluate the impact of temperature on the accumulation of these compounds, seeds from six different rice lines grown to maturity in replicate greenhouses in Gainesville, FL, were analyzed. The lines represented Oryza sativa indica, O. sativa japonica, and Oryza glaberrima of different origins. Temperatures were maintained near ambient at one end of each greenhouse and at approximately 4.5 degrees C above ambient at the other end. gamma-Oryzanols, tocopherols, and tocotrienols were extracted from whole seed (i.e., brown rice) and analyzed by HPLC. Tocotrienols and tocopherols varied widely between lines but changed only slightly with respect to temperature. In general, the proportions of alpha-tocotrienol and/or alpha-tocopherol increased at elevated temperature, whereas gamma-tocopherol and gamma-tocotrienol decreased. Six gamma-oryzanol peaks, identified on the basis of absorbance maxima at 330 nm and HPLC-mass spectrometry, were quantified. The most abundant component was 24-methylenecycloartanyl ferulate, present at 40-62% of total. Its levels increased 35-57% at elevated temperature in five of six lines, accounting for most of the change in total gamma-oryzanol. The results suggest that the physiological action of individual ferulated phytosterols should be investigated because their relative proportions in gamma-oryzanol can change.

Neutron diffraction and electrical transport studies on magnetic ordering in terbium at high pressures and low temperatures

DOE PAGES

Thomas, Sarah A.; Montgomery, Jeffrey M.; Tsoi, Georgiy M.; ...

2013-06-11

Neutron diffraction and electrical transport measurements have been carried out on the heavy rare earth metal terbium at high pressures and low temperatures in order to elucidate the onset of ferromagnetic order as a function of pressure. The electrical resistance measurements show a change in slope as the temperature is lowered through the ferromagnetic Curie temperature. The temperature of this ferromagnetic transition decreases from approximately 240 K at ambient pressure at a rate of –16.7 K/GPa up to a pressure of 3.6 GPa, at which point the onset of ferromagnetic order is suppressed. Neutron diffraction measurements as a function ofmore » pressure at temperatures ranging from 90 K to 290 K confirm that the change of slope in the resistance is associated with the ferromagnetic ordering, since this occurs at pressures similar to those determined from the resistance results at these temperatures. Furthermore, a change in ferromagnetic ordering as the pressure is increased above 3.6 GPa is correlated with the phase transition from the ambient hexagonal close packed (hcp) structure to an α-Sm type structure at high pressures.« less

Numerical study on the impact of ground heating and ambient wind speed on flow fields in street canyons

NASA Astrophysics Data System (ADS)

Li, Lei; Yang, Lin; Zhang, Li-Jie; Jiang, Yin

2012-11-01

The impact of ground heating on flow fields in street canyons under different ambient wind speed conditions was studied based on numerical methods. A series of numerical tests were performed, and three factors including height-to-width (H/W) ratio, ambient wind speed and ground heating intensity were taken into account. Three types of street canyon with H/W ratios of 0.5, 1.0 and 2.0, respectively, were used in the simulation and seven speed values ranging from 0.0 to 3.0 m s-1 were set for the ambient wind speed. The ground heating intensity, which was defined as the difference between the ground temperature and air temperature, ranged from 10 to 40 K with an increase of 10 K in the tests. The results showed that under calm conditions, ground heating could induce circulation with a wind speed of around 1.0 m s-1, which is enough to disperse pollutants in a street canyon. It was also found that an ambient wind speed threshold may exist for street canyons with a fixed H/W ratio. When ambient wind speed was lower than the threshold identified in this study, the impact of the thermal effect on the flow field was obvious, and there existed a multi-vortex flow pattern in the street canyon. When the ambient wind speed was higher than the threshold, the circulation pattern was basically determined by dynamic effects. The tests on the impact of heating intensity showed that a higher ground heating intensity could strengthen the vortical flow within the street canyon, which would help improve pollutant diffusion capability in street canyons.

Temperature and pressure dependent thermodynamic behavior of 2H-CuInO2

NASA Astrophysics Data System (ADS)

Bhamu, K. C.

2018-05-01

Density functional theory and quasi-harmonic Debye model has been used to study the thermodynamic properties of 2H-CuInO2. At the optimized structural parameters, pressure (0 to 80 GPa) dependent variation in the various thermodynamic properties, i.e. unit cell volume (V), bulk modulus (B), specific heat (Cv), Debye temperature (θD), Grüneisen parameter (γ) and thermal expansion coefficient (α) are calculated for various temperature values. The results predict that the pressure has significant effect on unit cell volume and bulk modulus while the temperature shows negligible effect on both parameters. With increasing temperature thermal expansion coefficient increase while with increasing pressure it decreases. The specific heat remains close to zero for ambient pressure and temperature values and it increases with increasing temperature. It is observed that the pressure has high impact on Debye temperature and Grüneisen parameter instead of temperature. Debye temperature and Grüneisen parameter both remains almost constant for the temperature range (0-300K) while Grüneisen parameter decrease with increasing pressure at constant temperature and Debye temperature increases rapidly with increasing pressure. An increase in Debye temperature with respect to pressure shows that the thermal vibration frequency changes rapidly.

Ocean acidification exerts negative effects during warming conditions in a developing Antarctic fish

PubMed Central

Flynn, Erin E; Bjelde, Brittany E; Miller, Nathan A

2015-01-01

Abstract Anthropogenic CO2 is rapidly causing oceans to become warmer and more acidic, challenging marine ectotherms to respond to simultaneous changes in their environment. While recent work has highlighted that marine fishes, particularly during early development, can be vulnerable to ocean acidification, we lack an understanding of how life-history strategies, ecosystems and concurrent ocean warming interplay with interspecific susceptibility. To address the effects of multiple ocean changes on cold-adapted, slowly developing fishes, we investigated the interactive effects of elevated partial pressure of carbon dioxide (pCO2) and temperature on the embryonic physiology of an Antarctic dragonfish (Gymnodraco acuticeps), with protracted embryogenesis (∼10 months). Using an integrative, experimental approach, our research examined the impacts of near-future warming [−1 (ambient) and 2°C (+3°C)] and ocean acidification [420 (ambient), 650 (moderate) and 1000 μatm pCO2 (high)] on survival, development and metabolic processes over the course of 3 weeks in early development. In the presence of increased pCO2 alone, embryonic mortality did not increase, with greatest overall survival at the highest pCO2. Furthermore, embryos were significantly more likely to be at a later developmental stage at high pCO2 by 3 weeks relative to ambient pCO2. However, in combined warming and ocean acidification scenarios, dragonfish embryos experienced a dose-dependent, synergistic decrease in survival and developed more slowly. We also found significant interactions between temperature, pCO2 and time in aerobic enzyme activity (citrate synthase). Increased temperature alone increased whole-organism metabolic rate (O2 consumption) and developmental rate and slightly decreased osmolality at the cost of increased mortality. Our findings suggest that developing dragonfish are more sensitive to ocean warming and may experience negative physiological effects of ocean acidification only in the presence of an increased temperature. In addition to reduced hatching success, alterations in development and metabolism due to ocean warming and acidification could have negative ecological consequences owing to changes in phenology (i.e. early hatching) in the highly seasonal Antarctic ecosystem. PMID:27293718

Ocean acidification exerts negative effects during warming conditions in a developing Antarctic fish.

PubMed

Flynn, Erin E; Bjelde, Brittany E; Miller, Nathan A; Todgham, Anne E

2015-01-01

Anthropogenic CO2 is rapidly causing oceans to become warmer and more acidic, challenging marine ectotherms to respond to simultaneous changes in their environment. While recent work has highlighted that marine fishes, particularly during early development, can be vulnerable to ocean acidification, we lack an understanding of how life-history strategies, ecosystems and concurrent ocean warming interplay with interspecific susceptibility. To address the effects of multiple ocean changes on cold-adapted, slowly developing fishes, we investigated the interactive effects of elevated partial pressure of carbon dioxide (pCO2) and temperature on the embryonic physiology of an Antarctic dragonfish (Gymnodraco acuticeps), with protracted embryogenesis (∼10 months). Using an integrative, experimental approach, our research examined the impacts of near-future warming [-1 (ambient) and 2°C (+3°C)] and ocean acidification [420 (ambient), 650 (moderate) and 1000 μatm pCO2 (high)] on survival, development and metabolic processes over the course of 3 weeks in early development. In the presence of increased pCO2 alone, embryonic mortality did not increase, with greatest overall survival at the highest pCO2. Furthermore, embryos were significantly more likely to be at a later developmental stage at high pCO2 by 3 weeks relative to ambient pCO2. However, in combined warming and ocean acidification scenarios, dragonfish embryos experienced a dose-dependent, synergistic decrease in survival and developed more slowly. We also found significant interactions between temperature, pCO2 and time in aerobic enzyme activity (citrate synthase). Increased temperature alone increased whole-organism metabolic rate (O2 consumption) and developmental rate and slightly decreased osmolality at the cost of increased mortality. Our findings suggest that developing dragonfish are more sensitive to ocean warming and may experience negative physiological effects of ocean acidification only in the presence of an increased temperature. In addition to reduced hatching success, alterations in development and metabolism due to ocean warming and acidification could have negative ecological consequences owing to changes in phenology (i.e. early hatching) in the highly seasonal Antarctic ecosystem.

Green Infrastructure Increases Biogeochemical Responsiveness, Vegetation Growth and Decreases Runoff in a Semi-Arid City, Tucson, AZ, USA

NASA Astrophysics Data System (ADS)

Meixner, T.; Papuga, S. A.; Luketich, A. M.; Rockhill, T.; Gallo, E. L.; Anderson, J.; Salgado, L.; Pope, K.; Gupta, N.; Korgaonkar, Y.; Guertin, D. P.

2017-12-01

Green Infrastructure (GI) is often viewed as a mechanism to minimize the effects of urbanization on hydrology, water quality, and other ecosystem services (including the urban heat island). Quantifying the effects of GI requires field measurements of the dimensions of biogeochemical, ecosystem, and hydrologic function that we expect GI to impact. Here we investigated the effect of GI features in Tucson, Arizona which has a low intensity winter precipitation regime and a high intensity summer regime. We focused on understanding the effect of GI on soil hydraulic and biogeochemical properties as well as the effect on vegetation and canopy temperature. Our results demonstrate profound changes in biogeochemical and hydrologic properties and vegetation growth between GI systems and nearby control sites. In terms of hydrologic properties GI soils had increased water holding capacity and hydraulic conductivity. GI soils also have higher total carbon, total nitrogen, and organic matter in general than control soils. Furthermore, we tested the sampled soils (control and GI) for differences in biogeochemical response upon wetting. GI soils had larger respiration responses indicating greater biogeochemical activity overall. Long-term Lidar surveys were used to investigate the differential canopy growth of GI systems versus control sites. The results of this analysis indicate that while a significant amount of time is needed to observe differences in canopy growth GI features due increase tree size and thus likely impact street scale ambient temperatures. Additionally monitoring of transpiration, soil moisture, and canopy temperature demonstrates that GI features increase vegetation growth and transpiration and reduce canopy temperatures. These biogeochemical and ecohydrologic results indicate that GI can increase the biogeochemical processing of soils and increase tree growth and thus reduce urban ambient temperatures.

Climate change drives a shift in peatland ecosystem plant community: implications for ecosystem function and stability.

PubMed

Dieleman, Catherine M; Branfireun, Brian A; McLaughlin, James W; Lindo, Zoë

2015-01-01

The composition of a peatland plant community has considerable effect on a range of ecosystem functions. Peatland plant community structure is predicted to change under future climate change, making the quantification of the direction and magnitude of this change a research priority. We subjected intact, replicated vegetated poor fen peat monoliths to elevated temperatures, increased atmospheric carbon dioxide (CO2 ), and two water table levels in a factorial design to determine the individual and synergistic effects of climate change factors on the poor fen plant community composition. We identify three indicators of a regime shift occurring in our experimental poor fen system under climate change: nonlinear decline of Sphagnum at temperatures 8 °C above ambient conditions, concomitant increases in Carex spp. at temperatures 4 °C above ambient conditions suggesting a weakening of Sphagnum feedbacks on peat accumulation, and increased variance of the plant community composition and pore water pH through time. A temperature increase of +4 °C appeared to be a threshold for increased vascular plant abundance; however the magnitude of change was species dependent. Elevated temperature combined with elevated CO2 had a synergistic effect on large graminoid species abundance, with a 15 times increase as compared to control conditions. Community analyses suggested that the balance between dominant plant species was tipped from Sphagnum to a graminoid-dominated system by the combination of climate change factors. Our findings indicate that changes in peatland plant community composition are likely under future climate change conditions, with a demonstrated shift toward a dominance of graminoid species in poor fens. © 2014 John Wiley & Sons Ltd.

Systemic salt loading decreases body temperature and increases heat-escape/cold-seeking behaviour via the central AT1 and V1 receptors in rats.

PubMed

Konishi, Masahiro; Nagashima, Kei; Kanosue, Kazuyuki

2002-11-15

Salt loading decreases body core temperature (T(core)) at neutral ambient temperature (26 degrees C) and increases heat-escape/cold-seeking behaviour in desalivated rats. In this study, we tested the hypothesis that brain angiotensin II (AII) and arginine vasopressin (AVP) are associated with these responses. Surgically desalivated rats (n = 28) were administered an injection (S.C., 10 ml kg(-1)) of either normal saline (154 mM, NS) or hypertonic saline (2500 mM, HS) following an intracerebroventricular injection (10 microl kg(-1)) of an AII AT(1)-receptor antagonist (candesartan, 5 microg microl(-1)), an AVP V(1)-receptor antagonist ((beta-mercapto-beta, beta-cyclopenta-methylene propionyl(1), O-Me-Tyr(2), Arg(8))-vasopressin, 0.5 microg microl(-1)), or normal saline (154 mM). Each rat was placed in a behaviour box, first at 26 degrees C for 1 h to allow the measurement of baseline T(core) and movement. The ambient temperature was then elevated to 40 degrees C for the next 2 h, during which time the rat was able to trigger a 0 degrees C air reward for 30 s by moving into a specific area of the box (operant behaviour). The S.C. HS significantly decreased baseline T(core) at 26 degrees C (36.5 +/- 0.1 degrees C) and increased counts of operant behaviour at 40 degrees C (57 +/- 3) compared with results obtained following S.C. NS injection (37.4 +/- 0.1 degrees C and 42 +/- 1, respectively). These responses to s.c. HS were inhibited by the intracerebroventricular injection of AT(1) (37.3 +/- 0.1 degrees C and 43 +/- 2, respectively; P < 0.05) and V(1) antagonists (37.2 +/- 0.2 degrees C and 42 +/- 2, respectively; P < 0.05), although administration of both antagonists with S.C. NS had no effect. These results suggest that brain AII and AVP are involved in the decrease in T(core) observed at neutral ambient temperature and the increase in heat-escape/cold-seeking behaviour in response to osmotic stimulation, via the central AT(1) and V(1) receptors, respectively

Oxygen consumption and body temperature of active and resting honeybees.

PubMed

Stabentheiner, Auton; Vollmann, Jutta; Kovac, Helmut; Crailsheim, Karl

2003-09-01

We measured the energy turnover (oxygen consumption) of honeybees (Apis mellifera carnica), which were free to move within Warburg vessels. Oxygen consumption of active bees varied widely depending on ambient temperature and level of activity, but did not differ between foragers (>18 d) and middle-aged hive bees (7-10 d). In highly active bees, which were in an endothermic state ready for flight, it decreased almost linearly, from a maximum of 131.4 microl O(2) min(-1) at 15 degrees C ambient temperature to 81.1 microl min(-1) at 25 degrees C, and reached a minimum of 29.9 microl min(-1) at 40 degrees C. In bees with low activity, it decreased from 89.3 microl O(2) min(-1) at 15 degrees C to 47.9 microl min(-1) at 25 degrees C and 14.7 microl min(-1) at 40 degrees C. Thermographic measurements of body temperature showed that with increasing activity, the bees invested more energy to regulate the thorax temperature at increasingly higher levels (38.8-41.2 degrees C in highly active bees) and were more accurate. Resting metabolism was determined in young bees of 1-7 h age, which are not yet capable of endothermic heat production with their flight muscles. Their energy turnover increased from 0.21 microl O(2) min(-1) at 10 degrees C to 0.38 microl min(-1) at 15 degrees C, 1.12 microl min(-1) at 25 degrees C, and 3.03 microl min(-1) at 40 degrees C. At 15, 25 and 40 degrees C, this was 343, 73 and 10 times below the values of the highly active bees, respectively. The Q(10) value of the resting bees, however, was not constant but varied in a U-shaped manner with ambient temperature. It decreased from 4.24 in the temperature range 11-21 degrees C to 1.35 in the range 21-31 degrees C, and increased again to 2.49 in the range 30-40 degrees C. We conclude that attempts to describe the temperature dependence of the resting metabolism of honeybees by Q(10) values can lead to considerable errors if the measurements are performed at only two temperatures. An acceptable approximation can be derived by calculation of an interpolated Q(10) according to the exponential function (V(O(2))=0.151 x 1.0784(T(a))) (interpolated Q(10)=2.12).

Marine heatwaves and optimal temperatures for microbial assemblage activity.

PubMed

Joint, Ian; Smale, Dan A

2017-02-01

The response of microbial assemblages to instantaneous temperature change was measured in a seasonal study of the coastal waters of the western English Channel. On 18 occasions between November 1999 and December 2000, bacterial abundance was assessed and temperature responses determined from the incorporation of 3 H leucine, measured in a temperature gradient from 5°C to 38°C. Q 10 values varied, being close to 2 in spring and summer but were >3 in autumn. There was a seasonal pattern in the assemblage optimum temperature (T opt ), which was out of phase with sea surface temperature. In July, highest 3 H-leucine incorporation rates were measured at temperatures that were only 2.8°C greater than ambient sea surface temperature but in winter, T opt was ∼20°C higher than the ambient sea surface temperature. Sea surface temperatures for the adjacent English Channel and Celtic Sea for 1982-2014 have periodically been >3°C higher than climatological mean temperatures. This suggests that discrete periods of anomalously high temperatures might be close to, or exceed, temperatures at which maximum microbial assemblage activity occurs. The frequency and magnitude of marine heatwaves are likely to increase as a consequence of anthropogenic climate change and extreme temperatures may influence the role of bacterial assemblages in biogeochemical processes. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Seasonal variation in the international normalized ratio of neonates and its relationship with ambient temperature.

PubMed

Iijima, Shigeo; Sekii, Katsuyuki; Baba, Toru; Ueno, Daizo; Ohishi, Akira

2016-07-19

The morbidity and mortality rates due to cardiovascular events such as myocardial infarction are known to exhibit seasonal variations. Moreover, changes in the ambient temperature are reportedly associated with an increase in these events, which may potentially involve blood coagulation markers. Bleeding due to vitamin K deficiency in neonates, which is associated with high mortality and a high frequency of neurological sequelae, is more commonly observed during the summer season and in warm regions in Japan. To determine the presence of seasonal variation and the influence of ambient temperature on blood coagulation markers in healthy term neonates, we assessed the international normalized ratio (INR) values measured using CoaguChek XS. We studied 488 consecutive healthy term neonates who were born at a perinatal center between July 2012 and June 2013. The INR values were measured using CoaguChek XS in 4-day-old neonates who received nursing care in the newborn nursery throughout the duration of hospitalization. The seasonal variations in the INR values and environmental effects on the INR were assessed. The mean monthly INR values peaked in July (1.13 ± 0.08), whereas the lowest values were observed in January (1.05 ± 0.08). Higher levels of INR were observed during the summer season (June to August) than during the winter season (December to February). Simple linear regression analysis indicated the presence of weakly positive but significant correlations between INR and outdoor temperature (r = 0.25, p < 0.001), outdoor relative humidity (r = 0.19, p < 0.001), and room relative humidity (r = 0.24, p < 0.001), and the presence of a significant negative correlation between INR and room temperature (r = -0.13, p = 0.02). Furthermore, multiple linear regression analysis showed that only outdoor temperature significantly influenced the INR. A seasonal variation in the INR values was observed among neonates, possibly due to the variation in ambient temperature. Even though the neonates received nursing care in the newborn nursery that was constantly air-conditioned, the outdoor temperature was the most influential factor on INR.

A Passive Radio-Frequency Identification (RFID) Gas Sensor With Self-Correction Against Fluctuations of Ambient Temperature

PubMed Central

Potyrailo, Radislav A.; Surman, Cheryl

2013-01-01

Uncontrolled fluctuations of ambient temperature in the field typically greatly reduce accuracy of gas sensors. In this study, we developed an approach for the self-correction against fluctuations of ambient temperature of individual gas and vapor sensors. The main innovation of our work is in the temperature correction which is accomplished without the need for a separate uncoated reference sensor or a separate temperature sensor. Our sensors are resonant inductor-capacitor-resistor (LCR) transducers coated with sensing materials and operated as multivariable passive (battery-free) radio-frequency identification (RFID) sensors. Using our developed approach, we performed quantitation of an exemplary vapor over the temperature range from 25 to 40 °C. This technical solution will be attractive in numerous applications where temperature stabilization of a gas sensor or addition of auxiliary temperature or uncoated reference sensors is prohibitive. PMID:23956496