Investigating the impact of land-use land-cover change on Indian summer monsoon daily rainfall and temperature during 1951–2005 using a regional climate model

DOE PAGES

Halder, Subhadeep; Saha, Subodh K.; Dirmeyer, Paul A.; ...

2016-05-10

Daily moderate rainfall events, which constitute a major portion of seasonal summer monsoon rainfall over central India, have decreased significantly during the period 1951 through 2005. On the other hand, mean and extreme near-surface daily temperature during the monsoon season have increased by a maximum of 1–1.5 °C. Using simulations made with a high-resolution regional climate model (RegCM4) and prescribed land cover of years 1950 and 2005, it is demonstrated that part of the changes in moderate rainfall events and temperature have been caused by land-use/land-cover change (LULCC), which is mostly anthropogenic. Model simulations show that the increase in seasonal mean and extreme temperature over centralmore » India coincides with the region of decrease in forest and increase in crop cover. Our results also show that LULCC alone causes warming in the extremes of daily mean and maximum temperatures by a maximum of 1–1.2 °C, which is comparable with the observed increasing trend in the extremes. Decrease in forest cover and simultaneous increase in crops not only reduces the evapotranspiration over land and large-scale convective instability, but also contributes toward decrease in moisture convergence through reduced surface roughness. These factors act together in reducing significantly the moderate rainfall events and the amount of rainfall in that category over central India. Additionally, the model simulations are repeated by removing the warming trend in sea surface temperatures over the Indian Ocean. As a result, enhanced warming at the surface and greater decrease in moderate rainfall events over central India compared to the earlier set of simulations are noticed. Results from these additional experiments corroborate our initial findings and confirm the contribution of LULCC in the decrease in moderate rainfall events and increase in daily mean and extreme temperature over India. Therefore, this study demonstrates the important implications of LULCC over India during the monsoon season. Although, the regional climate model helps in better resolving land–atmosphere feedbacks over the Indian region, the inferences do depend on the fidelity of the model in capturing the features of Indian monsoon realistically. Lastly, it is proposed that similar studies using a suite of climate models will further enrich our understanding about the role of LULCC in the Indian monsoon climate.« less

Ecosystem response to climatic variables - air temperature and precipitation: How can these variables alter plant productions in C4-grass dominant ecosystem?

NASA Astrophysics Data System (ADS)

Jung, C. G.; Jiang, L.; Luo, Y.

2017-12-01

Understanding net primary production (NPP) response to the key climatic variables, temperature and precipitation, is essential since the response could be represented by one of future consequences from ecosystem responses. Under future climatic warming, fluctuating precipitation is expected. In addition, NPP solely could not explain whole ecosystem response; therefore, not only NPP, but also above- and below-ground NPP (ANPP and BNPP, respectively) need to be examined. This examination needs to include how the plant productions response along temperature and precipitation gradients. Several studies have examined the response of NPP against each of single climatic variable, but understanding the response of ANPP and BNPP to the multiple variables is notably poor. In this study, we used the plant productions data (NPP, ANPP, and BNPP) with climatic variables, i.e., air temperature and precipitation, from 1999 to 2015 under warming and clipping treatments (mimicking hay-harvesting) in C4-grass dominant ecosystem located in central Oklahoma, United States. Firstly, we examined the nonlinear relationships with the climatic variables for NPP, ANPP and BNPP; and then predicted possible responses in the temperature - precipitation space by using a linear mixed effect model. Nonlinearities of NPP, ANPP and BNPP to the climatic variables have been found to show unimodal curves, and nonlinear models have better goodness of fit as shown lower Akaike information criterion (AIC) than linear models. Optimum condition for NPP is represented at high temperature and precipitation level whereas BNPP is maximized at moderate precipitation levels while ANPP has same range of NPP's optimum condition. Clipping significantly reduced ANPP while there was no clipping effect on NPP and BNPP. Furthermore, inclining NPP and ANPP have shown in a range from moderate to high precipitation level with increasing temperature while inclining pattern for BNPP was observed in moderate precipitation level. Overall, the C4-grass dominant ecosystem has a potential for considerable increases in NPP in hotter and wetter conditions as shown a range from moderate to high temperature and precipitation levels; ANPP has peaked at the high temperature and precipitation level, but maximum BNPP needs moderate precipitation level and high temperature.

Low to moderate temperature nanolaminate heater

DOEpatents

Eckels, J Del [Livermore, CA; Nunes, Peter J [Danville, CA; Simpson, Randall L [Livermore, CA; Hau-Riege, Stefan [Fremont, CA; Walton, Chris [Oakland, CA; Carter, J Chance [Livermore, CA; Reynolds, John G [San Ramon, CA

2011-01-11

A low to moderate temperature heat source comprising a high temperature energy source modified to output low to moderate temperatures wherein the high temperature energy source modified to output low to moderate temperatures is positioned between two thin pieces to form a close contact sheath. In one embodiment the high temperature energy source modified to output low to moderate temperatures is a nanolaminate multilayer foil of reactive materials that produces a heating level of less than 200.degree. C.

Does Temperature Modify the Effects of Rain and Snow Precipitation on Road Traffic Injuries?

PubMed

Lee, Won-Kyung; Lee, Hye-Ah; Hwang, Seung-sik; Kim, Ho; Lim, Youn-Hee; Hong, Yun-Chul; Ha, Eun-Hee; Park, Hyesook

2015-01-01

There are few data on the interaction between temperature and snow and rain precipitation, although they could interact in their effects on road traffic injuries. The integrated database of the Korea Road Traffic Authority was used to calculate the daily frequency of road traffic injuries in Seoul. Weather data included rain and snow precipitation, temperature, pressure, and fog from May 2007 to December 2011. Precipitation of rain and snow were divided into nine and six temperature range categories, respectively. The interactive effects of temperature and rain and snow precipitation on road traffic injuries were analyzed using a generalized additive model with a Poisson distribution. The risk of road traffic injuries during snow increased when the temperature was below freezing. Road traffic injuries increased by 6.6% when it was snowing and above 0 °C, whereas they increased by 15% when it was snowing and at or below 0 °C. In terms of heavy rain precipitation, moderate temperatures were related to an increased prevalence of injuries. When the temperature was 0-20 °C, we found a 12% increase in road traffic injuries, whereas it increased by 8.5% and 6.8% when it was <0 °C and >20 °C, respectively. The interactive effect was consistent across the traffic accident subtypes. The effect of adverse weather conditions on road traffic injuries differed depending on the temperature. More road traffic injuries were related to rain precipitation when the temperature was moderate and to snow when it was below freezing.

Does Temperature Modify the Effects of Rain and Snow Precipitation on Road Traffic Injuries?

PubMed Central

Lee, Won-Kyung; Lee, Hye-Ah; Hwang, Seung-sik; Kim, Ho; Lim, Youn-Hee; Hong, Yun-Chul; Ha, Eun-Hee; Park, Hyesook

2015-01-01

Background There are few data on the interaction between temperature and snow and rain precipitation, although they could interact in their effects on road traffic injuries. Methods The integrated database of the Korea Road Traffic Authority was used to calculate the daily frequency of road traffic injuries in Seoul. Weather data included rain and snow precipitation, temperature, pressure, and fog from May 2007 to December 2011. Precipitation of rain and snow were divided into nine and six temperature range categories, respectively. The interactive effects of temperature and rain and snow precipitation on road traffic injuries were analyzed using a generalized additive model with a Poisson distribution. Results The risk of road traffic injuries during snow increased when the temperature was below freezing. Road traffic injuries increased by 6.6% when it was snowing and above 0°C, whereas they increased by 15% when it was snowing and at or below 0°C. In terms of heavy rain precipitation, moderate temperatures were related to an increased prevalence of injuries. When the temperature was 0–20°C, we found a 12% increase in road traffic injuries, whereas it increased by 8.5% and 6.8% when it was <0°C and >20°C, respectively. The interactive effect was consistent across the traffic accident subtypes. Conclusions The effect of adverse weather conditions on road traffic injuries differed depending on the temperature. More road traffic injuries were related to rain precipitation when the temperature was moderate and to snow when it was below freezing. PMID:26073021

Effect of inspiratory resistance to prolonged exercise in a hot environment wearing protective clothing

NASA Astrophysics Data System (ADS)

Jetté, Maurice; Quenneville, Josée; Thoden, James; Livingstone, Sydney

1992-09-01

The effects of inspiratory resistance on prolonged work in a hot environment wearing a nuclear, bacteriological and chemical warfare (NBCW) mask and overgarment were assessed in 10 males. Subjects walked on a treadmill at 5 km/hr, 2% gradient, until their core temperature reached 39° C or for a duration of 90 min. Rectal temperature, heart rate, ventilation, oxygen consumption and rate of perceived breathing were measured. There were no differences between break-point time without the canister (62.2 ± 21 min) and with the canister (58.9 ± 17 min). Regression analysis indicated that the mean core temperature increased by 0.02° C for every minute of work performed and heart rate by 6 beats/min for every increase of 0.2° C in core temperature. Reduction in heat transfer brought about by wearing the protective overgarment and mask with or without the canister will significantly increase core temperature and limit the performance of moderate work to approximately 1 h in a moderately fit individual.

Molding process for imidazopyrrolone polymers

NASA Technical Reports Server (NTRS)

Johnson, C. L. (Inventor)

1973-01-01

A process is described for producing shaped articles of imidazopyrrolone polymers comprising molding imidazopyrrolone polymer molding power under pressure and at a temperature greater than 475 C. Moderate pressures may be employed. Preferably, prior to molding, a preform is prepared by isostatic compression. The preform may be molded at a relatively low initial pressure and temperature; as the temperature is increased to a value greater than 475 C., the pressure is also increased.

Heat and emergency room admissions in the Netherlands.

PubMed

van Loenhout, Joris Adriaan Frank; Delbiso, Tefera Darge; Kiriliouk, Anna; Rodriguez-Llanes, Jose Manuel; Segers, Johan; Guha-Sapir, Debarati

2018-01-05

Due to a global warming-related increase in heatwaves, it is important to obtain detailed understanding of the relationship between heat and health. We assessed the relationship between heat and urgent emergency room admissions in the Netherlands. We collected daily maximum temperature and relative humidity data over the period 2002-2007. Daily urgent emergency room admissions were divided by sex, age group and disease category. We used distributed lag non-linear Poisson models, estimating temperature-admission associations. We estimated the relative risk (RR) for urgent hospital admissions for a range of temperatures compared to a baseline temperature of 21 °C. In addition, we compared the impact of three different temperature scenarios on admissions using the RR. There is a positive relationship between increasing temperatures above 21 °C and the RR for urgent emergency room admissions for the disease categories 'Potential heat-related diseases' and 'Respiratory diseases'. This relationship is strongest in the 85+ group. The RRs are strongest for lag 0. For admissions for 'circulatory diseases', there is only a small significant increase of RRs within the 85+ age group for moderate heat, but not for extreme heat. The RRs for a one-day event with extreme heat are comparable to the RRs for multiple-day events with moderate heat. Hospitals should adjust the capacity of their emergency departments on warm days, and the days immediately thereafter. The elderly in particular should be targeted through prevention programmes to reduce harmful effects of heat. The fact that this increase in admissions already occurs in temperatures above 21 °C is different from previous findings in warmer countries. Given the similar impact of three consecutive days of moderate heat and one day of extreme heat on admissions, criteria for activation of national heatwave plans need adjustments based on different temperature scenarios.

Temperature and salinity regulation of growth and gas exchange of Salicornia fruticosa (L.) L.

PubMed

Abdulrahman, Farag Saleh; Williams, George J

1981-03-01

Salicornia fruticosa was collected from a salt marsh on the Mediterranean sea coast in Libya. Growth and gas exchange of this C 3 species were monitered in plants pretreated at various NaCl concentrations (0, 171, 342, 513 and 855 mM). Maximum growth was at 171 mM NaCl under cool growth conditions (20/10° C) and at 342 mM NaCl under warm growth conditions (30/15° C) with minimum growth at 0 mM NaCl (control). Net photosynthesis (Pn) was greatest in plants grown in 171 mM NaCl with plants grown at 513 and 855 mM having lowest rates. Maximum Pn was at 20-25° C shoot temperatures with statistically significant reductions at 30° C in control plants while salt treated plants showed such reductions at 35° C. Salt treatments increased dark respiration over the control at 171 and 342 mM but reduced it at higher concentrations. Photorespiration was reduced by salt treatment and increased by increasing shoot temperature. Greatest transpiration was in 171 mM NaCl treated plants and increasing shoot temperature increased transpiration in all treatments. Stomatal resistance to CO 2 influx was influenced only moderately by temperature while increasing salinity resulted in increased stomatal resistance. In general both temperature and salinity increased the mesophyll resistance to CO 2 influx. The species seems adapted to the warm saline habitat along the Mediterranean sea coast, at least partially, by its ability to maintain relatively high Pn at moderate NaCl concentrations over a broad range of shoot temperatures.

Warm water temperatures and shifts in seasonality increase trout recruitment but only moderately decrease adult size in western North American tailwaters

USGS Publications Warehouse

Dibble, Kimberly L.; Yackulic, Charles B.; Kennedy, Theodore A.

2018-01-01

Dams throughout western North America have altered thermal regimes in rivers, creating cold, clear “tailwaters” in which trout populations thrive. Ongoing drought in the region has led to highly publicized reductions in reservoir storage and raised concerns about potential reductions in downstream flows. Large changes in riverine thermal regimes may also occur as reservoir water levels drop, yet this potential impact has received far less attention. We analyzed historic water temperature and fish population data to anticipate how trout may respond to future changes in the magnitude and seasonality of river temperatures. We found that summer temperatures were inversely related to reservoir water level, with warm temperatures associated with reduced storage and with dams operated as run-of-river units. Variation in rainbow trout (Oncorhynchus mykiss) recruitment was linked to water temperature variation, with a 5-fold increase in recruitment occurring at peak summer temperatures (18 °C vs. 7 °C) and a 2.5-fold increase in recruitment when peak temperatures occurred in summer rather than fall. Conversely, adult trout size was only moderately related to temperature. Rainbow and brown trout (Salmo trutta) size decreased by ~24 mm and 20 mm, respectively, as mean annual and peak summer temperatures increased. Further, rainbow trout size decreased by ~29 mm with an earlier onset of cold winter temperatures. While increased recruitment may be the more likely outcome of a warmer and drier climate, density-dependent growth constraints could exacerbate temperature-dependent growth reductions. As such, managers may consider implementing flows to reduce recruitment or altering infrastructure to maintain coldwater reservoir releases.

Enhancing Rubisco activity at higher temperatures by re-engineering of Rubisco activase

USDA-ARS?s Scientific Manuscript database

This report discusses the possibility of increasing plant performance under moderate heat stress by improving the thermal stability of Rubisco activase. • The research is driven by the observation that photosynthesis is acutely sensitive to inhibition by moderate heat stress and that this inhibitio...

Efficacy of reflective insulation in reducing heat stress on dairy calves housed in polyethylene calf hutches.

PubMed

Carter, B H; Friend, T H; Garey, S M; Sawyer, J A; Alexander, M B; Tomazewski, M A

2014-01-01

The objective of this study was to determine the ability of radiant insulation hutch covers to moderate the effect of ambient temperature and radiant energy on calves housed in polyethylene hutches. The insulation had a double layer of polyethylene bubble film laminated between a layer of aluminum foil and white polyethylene (reflectance = 95%, R value (ft(2) · °F ·h/Btu) = 2.7). In each of two experiments (exp.), hutches were either uninsulated (control) or covered with reflective insulation across the top and sides of the hutch leaving the front, back, and pen exposed. Each hutch had a 1.2 × 1.8-m attached outdoor wire pen. In both exp., rate of increase of interior hutch temperature relative to ambient temperature was lower in insulated hutches (P < 0.001) indicating they were warmer at low THI and cooler at high THI. In exp. 1, increase in respiration rate and ear canal temperature of the calves, relative to THI, were moderated in insulated hutches (P < 0.001). In Exp. 2, respiration rate was not affected by treatment (P = 0.50), but increased with increasing THI (P < 0.001). Mean ADG did not differ among treatments in either exp. (P > 0.21). Insulating calf hutches with reflective insulation moderated hutch microclimate, and improved calf comfort, but did not translate to improvements in economically relevant variables such as ADG.

The role of humidity in determining scenarios of perceived temperature extremes in Europe

NASA Astrophysics Data System (ADS)

Scoccimarro, Enrico; Fogli, Pier Giuseppe; Gualdi, Silvio

2017-11-01

An increase of the 2 m temperature over Europe is expected within the current century. In order to consider health impacts, it is important to evaluate the combined effect of temperature and humidity on the human body. To achieve this, projections of a basic index—the humidex—representative of the perceived temperature, under different scenarios and periods, have been investigated. The simultaneous occurrence of observed extreme temperature events and perceived extreme temperature events is seldom found within the present climate, reinforcing the importance of investigating the combination of the two fields. A set of 10 km resolution regional climate simulations, provided within the EURO-CORDEX multi-model effort, demonstrates an ability in representing moderate to extreme events of perceived temperature over the present climate, and to be useful as a tool for quantifying future changes in geographical patterns of exposed areas over Europe. Following the RCP8.5 emission scenario, an expansion of the area subject to dangerous conditions is suggested from the middle of the current century, reaching 60 °N. The most significant increase of perceived extreme temperature conditions is found comparing the 2066-2095 projections to the 1976-2005 period; bearing in mind that changes in relative humidity may either amplify or offset the health effects of temperature, a less pronounced projected reduction of relative humidity in the north-eastern part of Europe, associated with extreme humidex events, makes northern Europe the most prone region to an increase of moderate to extreme values of perceived temperature. This is in agreement with a pronounced projected specific humidity increase.

Climate change impacts on projections of excess mortality at ...

EPA Pesticide Factsheets

We project the change in ozone-related mortality burden attributable to changes in climate between a historical (1995-2005) and near-future (2025-2035) time period while incorporating a non-linear and synergistic effect of ozone and temperature on mortality. We simulate air quality from climate projections varying only biogenic emissions and holding anthropogenic emissions constant, thus attributing changes in ozone only to changes in climate and independent of changes in air pollutant emissions. We estimate non-linear, spatially varying, ozone-temperature risk surfaces for 94 US urban areas using observeddata. Using the risk surfaces and climate projections we estimate daily mortality attributable to ozone exceeding 40 p.p.b. (moderate level) and 75 p.p.b. (US ozone NAAQS) for each time period. The average increases in city-specific median April-October ozone and temperature between time periods are 1.02 p.p.b. and 1.94 °F; however, the results variedby region . Increases in ozone because of climate change result in an increase in ozone mortality burden. Mortality attributed to ozone exceeding 40 p.p.b. increases by 7.7% (1 .6-14.2%). Mortality attributed to ozone exceeding 75 p.p.b. increases by 14.2% (1.628.9%). The absolute increase in excess ozone mortality is larger for changes in moderate ozone levels, reflecting the larger number of days with moderate ozone levels. In this study we evaluate changes in ozone related mortality due to changes in biogenic f

Carvacrol suppresses high pressure high temperature inactivation of Bacillus cereus spores.

PubMed

Luu-Thi, Hue; Corthouts, Jorinde; Passaris, Ioannis; Grauwet, Tara; Aertsen, Abram; Hendrickx, Marc; Michiels, Chris W

2015-03-16

The inactivation of bacterial spores generally proceeds faster and at lower temperatures when heat treatments are conducted under high pressure, and high pressure high temperature (HPHT) processing is, therefore, receiving an increased interest from food processors. However, the mechanisms of spore inactivation by HPHT treatment are poorly understood, particularly at moderately elevated temperature. In the current work, we studied inactivation of the spores of Bacillus cereus F4430/73 by HPHT treatment for 5 min at 600MPa in the temperature range of 50-100°C, using temperature increments of 5°C. Additionally, we investigated the effect of the natural antimicrobial carvacrol on spore germination and inactivation under these conditions. Spore inactivation by HPHT was less than about 1 log unit at 50 to 70°C, but gradually increased at higher temperatures up to about 5 log units at 100°C. DPA release and loss of spore refractility in the spore population were higher at moderate (≤65°C) than at high (≥70°C) treatment temperatures, and we propose that moderate conditions induced the normal physiological pathway of spore germination resulting in fully hydrated spores, while at higher temperatures this pathway was suppressed and replaced by another mechanism of pressure-induced dipicolinic acid (DPA) release that results only in partial spore rehydration, probably because spore cortex hydrolysis is inhibited. Carvacrol strongly suppressed DPA release and spore rehydration during HPHT treatment at ≤65°C and also partly inhibited DPA release at ≥65°C. Concomitantly, HPHT spore inactivation was reduced by carvacrol at 65-90°C but unaffected at 95-100°C. Copyright © 2014 Elsevier B.V. All rights reserved.

[Impact of low temperature in young ear formation stage on rice seed setting.

PubMed

Ma, Shu Qing; Liu, Xiao Hang; Deng, Kui Cai; Quan, Hu Jie; Tong, Li Yuan; Xi, Zhu Xiang; Chai, Qing Rong; Yang, Jun

2018-01-01

A low temperature treatment in rice booting key period was executed on the north slope of Changbai Mountains to construct the impact model of low temperature on rice shell rate, and to reveal the effects of low temperature at different stages of rice young panicle on seed setting. The results showed that effects of low temperature in the young ear formation stage on rice shell rate generally followed the logarithmic function, the lower the temperature was, the greater the temperature influence coefficient was, and the longer the low temperature duration was, the higher rice shell rate was. The seed setting rate was most sensitive to low temperature in the middle time of booting stage (the period from formation to meiosis of the pollen mother cell), followed by the early and later stages. During the booting stage, with 1 ℃ decrease of daily temperature under 2-, 3- and 5-day low temperature treatments, the shell rate increased by 0.5, 1.7 and 4.3 percentage, respectively, and with 1 ℃ decrease of daily minimum temperature, the shell rate increased by 0.4,1.8 and 4.5 percentage, respectively. The impact of 2-day low temperature was smaller than that of 3 days or more. The impact of accumulative cold-temperature on the shell rate followed exponential function. In the range of harmful low temperature, rice shell rate increased about 8.5 percentage with the accumulative cold-temperature increasing 10 ℃·d. When the 3 days average temperature dropped to 21.6, 18.0 and 15.0 ℃, or the 5 days average temperature dropped to 22.0, 20.4 and 18.5 ℃, or the accumulative cold-temperature was more than 8, 19, 26 ℃·d, the light, moderate and severe booting stage chilling injury would occur, respectively. In Northeast China, low temperature within 2 d in rice booting stage might not cause moderate and severe chilling injury.

Determining critical pre- and post-anthesis periods and physiological processes in Lycopersicon esculentum Mill. exposed to moderately elevated temperatures.

PubMed

Sato, Suguru; Peet, Mary M; Thomas, Judith F

2002-05-01

To determine the thermosensitive periods and physiological processes in tomato flowers exposed to moderately elevated temperatures, tomato plants (Lycopersicon esculentum Mill., cv. NC 8288) were grown at 28/22 degrees C or 32/26 degrees C day/night temperature regimes and then transferred to the opposite regime for 0-15 d before or 0-24 h after anthesis. For plants initially grown at 28/22 degrees C, moderate temperature stress before anthesis decreased the percentage of fruit set per plant, but did not clarify the thermosensitive period. The same level of stress did not significantly reduce fruit set when applied immediately after anthesis. For plants initially grown at 32/26 degrees C, fruit set was completely prevented unless a relief period of more than 5 d was provided before anthesis. The same level of stress relief for 3-24 h after anthesis also increased fruit set. Plants were most sensitive to 32/26 degrees C temperatures 7-15 d before anthesis. Microscopic investigation of anthers in plants grown continuously at high temperature indicated disruption of development in the pollen, endothecium, epidermis, and stomium. This disruption was reduced, but still observable in plants relieved from high temperature for 10 d before anthesis.

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.

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.

Climate change (elevated CO₂, elevated temperature and moderate drought) triggers the antioxidant enzymes' response of grapevine cv. Tempranillo, avoiding oxidative damage.

PubMed

Salazar-Parra, Carolina; Aguirreolea, Jone; Sánchez-Díaz, Manuel; Irigoyen, Juan José; Morales, Fermín

2012-02-01

Photosynthetic carbon fixation (A(N) ) and photosynthetic electron transport rate (ETR) are affected by different environmental stress factors, such as those associated with climate change. Under stress conditions, it can be generated an electron excess that cannot be consumed, which can react with O₂, producing reactive oxygen species. This work was aimed to evaluate the influence of climate change (elevated CO₂, elevated temperature and moderate drought) on the antioxidant status of grapevine (Vitis vinifera) cv. Tempranillo leaves, from veraison to ripeness. The lowest ratios between electrons generated (ETR) and consumed (A(N) + respiration + photorespiration) were observed in plants treated with elevated CO₂ and elevated temperature. In partially irrigated plants under current ambient conditions, electrons not consumed seemed to be diverted to alternative ways. Oxidative damage to chlorophylls and carotenoids was not observed. However, these plants had increases in thiobarbituric acid reacting substances, an indication of lipid peroxidation. These increases matched well with an early rise of H₂O₂ and antioxidant enzyme activities, superoxide dismutase (EC 1.15.1.1), ascorbate peroxidase (EC 1.11.1.11) and catalase (EC 1.11.1.6). Enzymatic activities were maintained high until ripeness. In conclusion, plants grown under current ambient conditions and moderate drought were less efficient to cope with oxidative damage than well-irrigated plants, and more interestingly, plants grown under moderate drought but treated with elevated CO₂ and elevated temperature were not affected by oxidative damage, mainly because of higher rates of electrons consumed in photosynthetic carbon fixation. Copyright © Physiologia Plantarum 2011.

[Effects of climate warming and drying on millet yield in Gansu Province and related countermeasures].

PubMed

Cao, Ling; Wang, Qiang; Deng, Zhen-yong; Guo, Xiao-qin; Ma, Xing-xiang; Ning, Hui-fang

2010-11-01

Based on the data of air temperature, precipitation, and millet yield from Ganzhou, Anding, and Xifeng, the representative stations in Hexi moderate arid oasis irrigation area, moderate sub-arid dry area in middle Gansu, and moderate sub-humid dry area in eastern Gansu, respectively, this paper calculated the regional active accumulated temperature of > or = 0 degrees C, > or =5 degrees C, > or =10 degrees C, > or =15 degrees C, and > or =20 degrees C in millet growth period, and the average temperature and precipitation in millet key growth stages. The millet climatic yield was isolated by orthogonal polynomial, and the change characteristics of climate and millet climatic yield as well as the effects of climate change on millet yield were analyzed by statistical methods of linear tendency, cumulative anomaly, and Mann-Kendall. The results showed that warming and drying were the main regional features in the modern climatic change of Gansu. The regional temperature had a significant upward trend since the early 1990s, while the precipitation was significantly reduced from the late 1980s. There were significant correlations between millet yield and climatic factors. The millet yield in dry areas increased with the increasing temperature and precipitation in millet key growth stages, and that in Hexi Corridor area increased with increasing temperature. Warming and drying affected millet yield prominently. The weather fluctuation index of regional millet yield in Xifeng, Anding, and Ganzhou accounted for 73%, 72%, and 54% of real output coefficient variation, respectively, and the percentages increased significantly after warming. Warming was conducive to the increase of millet production, and the annual increment of millet climatic yield in Xifeng, Anding, and Ganzhou after warming was 30.6, 43.1, and 121.1 kg x hm(-2), respectively. Aiming at the warming and drying trend in Gansu Province in the future, the millet planting area in the Province should be further expanded, and the millet planting structure should be adjusted. At the same time, according to the different regional and yearly climatic types, different varieties should be selected, and various planting measures should be taken.

Effects of urban tree canopy loss on land surface temperature magnitude and timing

Treesearch

Arthur Elmes; John Rogan; Christopher Williams; Samuel Ratick; David Nowak; Deborah Martin

2017-01-01

Urban Tree Canopy (UTC) plays an important role in moderating the Surface Urban Heat Island (SUHI) effect, which poses threats to human health due to substantially increased temperatures relative to rural areas. UTC coverage is associated with reduced urban temperatures, and therefore benefits both human health and reducing energy use in cities. Measurement of this...

Thermal study of the Missouri River in North Dakota using infrared imagery

USGS Publications Warehouse

Crosby, Orlo A.

1971-01-01

The study indicates a marked decrease in water temperature in the Missouri River prior to early fall and a moderate increase in temperature in late fall because of the Lake Sakakawea impoundment. At the present time, thermal additions generated by the powerplants have little effect on the temperature regimen of the Missouri River at high rates of river discharge.

Pregnant women maintain body temperatures within safe limits during moderate-intensity aqua-aerobic classes conducted in pools heated up to 33 degrees Celsius: an observational study.

PubMed

Brearley, Amanda L; Sherburn, Margaret; Galea, Mary P; Clarke, Sandy J

2015-10-01

What is the body temperature response of healthy pregnant women exercising at moderate intensity in an aqua-aerobics class where the water temperature is in the range of 28 to 33 degrees Celsius, as typically found in community swimming pools? An observational study. One hundred and nine women in the second and third trimester of pregnancy who were enrolled in a standardised aqua-aerobics class. Tympanic temperature was measured at rest pre-immersion (T1), after 35minutes of moderate-intensity aqua-aerobic exercise (T2), after a further 10minutes of light exercise while still in the water (T3) and finally on departure from the facility (T4). The range of water temperatures in seven indoor community pools was 28.8 to 33.4 degrees Celsius. Body temperature increased by a mean of 0.16 degrees Celsius (SD 0.35, p<0.001) at T2, was maintained at this level at T3 and had returned to pre-immersion resting values at T4. Regression analysis demonstrated that the temperature response was not related to the water temperature (T2 r = -0.01, p = 0.9; T3 r = -0.02, p=0.9; T4 r=0.03, p=0.8). Analysis of variance demonstrated no difference in body temperature response between participants when grouped in the cooler, medium and warmer water temperatures (T2 F=0.94, p=0.40; T3 F=0.93, p=0.40; T4 F=0.70, p=0.50). Healthy pregnant women maintain body temperatures within safe limits during moderate-intensity aqua-aerobic exercise conducted in pools heated up to 33 degrees Celsius. The study provides evidence to inform guidelines for safe water temperatures for aqua-aerobic exercise during pregnancy. Copyright © 2015 Australian Physiotherapy Association. Published by Elsevier B.V. All rights reserved.

The effect of the menstrual cycle and water consumption on physiological responses during prolonged exercise at moderate intensity in hot conditions.

PubMed

Hashimoto, Hideki; Ishijima, Toshimichi; Suzuki, Katsuhiko; Higuchi, Mitsuru

2016-09-01

Reproductive hormones are likely to be involved in thermoregulation through body fluid dynamics. In the present study, we aimed to investigate the effect of the menstrual cycle and water consumption on physiological responses to prolonged exercise at moderate intensity in hot conditions. Eight healthy young women with regular menstrual cycles performed cycling exercise for 90 minutes at 50% V̇O2peak intensity during the low progesterone (LP) level phase and high progesterone (HP) level phase, with or without water consumption, under hot conditions (30°C, 50% relative humidity). For the water consumption trials, subjects ingested water equivalent to the loss in body weight that occurred in the earlier non-consumption trial. For all four trials, rectal temperature, cardiorespiratory responses, and ratings of perceived exertion (RPE) were measured. Throughout the 90-minute exercise period, rectal temperatures during HP were higher than during LP by an average of 0.4 °C in the non-consumption trial (P<0.01) and 0.2 °C in the water consumption trial (P<0.05). During exercise, water consumption affected the changes in rectal temperature and heat rate (HR) during HP, but it did not exert these effects during LP. Furthermore, we found a negative correlation between estradiol levels and rectal temperature during LP. During prolonged exercise at moderate intensity under hot conditions, water consumption is likely to be useful for suppressing the associated increase in body temperature and HR, particularly during HP, whereas estradiol appears to be useful for suppressing the increase in rectal temperature during LP.

Environmental tests of metallization systems for terrestrial photovoltaic cells

NASA Technical Reports Server (NTRS)

Alexander, P., Jr.

1985-01-01

Seven different solar cell metallization systems were subjected to temperature cycling tests and humidity tests. Temperature cycling excursions were -50 deg C to 150 deg C per cycle. Humidity conditions were 70 deg C at 98% relative humidity. The seven metallization systems were: Ti/Ag, Ti/Pd/Ag, Ti/Pd/Cu, Ni/Cu, Pd/Ni/Solder, Cr/Pd/Ag, and thick film Ag. All metallization systems showed a slight to moderate decrease in cell efficiencies after subjection to 1000 temperature cycles. Six of the seven metallization systems also evidenced slight increases in cell efficiencies after moderate numbers of cycles, generally less than 100 cycles. The copper based systems showed the largest decrease in cell efficiencies after temperature cycling. All metallization systems showed moderate to large decreases in cell efficiencies after 123 days of humidity exposure. The copper based systems again showed the largest decrease in cell efficiencies after humidity exposure. Graphs of the environmental exposures versus cell efficiencies are presented for each metallization system, as well as environmental exposures versus fill factors or series resistance.

Mapping Sensory Spots for Moderate Temperatures on the Back of Hand.

PubMed

Yang, Fan; Chen, Guixu; Zhou, Sikai; Han, Danhong; Xu, Jingjing; Xu, Shengyong

2017-12-04

Thermosensation with thermoreceptors plays an important role in maintaining body temperature at an optimal state and avoiding potential damage caused by harmful hot or cold environmental temperatures. In this work, the locations of sensory spots for sensing moderate temperatures of 40-50 °C on the back of the hands of young Chinese people were mapped in a blind-test manner with a thermal probe of 1.0 mm spatial resolution. The number of sensory spots increased along with the testing temperature; however, the surface density of sensory spots was remarkably lower than those reported previously. The locations of the spots were irregularly distributed and subject-dependent. Even for the same subject, the number and location of sensory spots were unbalanced and asymmetric between the left and right hands. The results may offer valuable information for designing artificial electronic skin and wearable devices, as well as for clinical applications.

The Environment and the Microbial Ecology of Human Skin

PubMed Central

McBride, Mollie E.; Duncan, W. Christopher; Knox, J. M.

1977-01-01

Microbial flora of the skin of three human population groups representing different natural environments was examined quantitatively and qualitatively to determine whether environmental differences in temperature and humidity can influence the microbial flora of normal skin. Five anatomical skin sites - hands, back, axillae, groin, and feet - were sampled from 10 subjects working in a high-humidity, high-temperature environment, 10 subjects from a low-temperature, high-humidity environment, and 10 subjects working in a moderate-temperature and low-humidity environment. Bacterial populations were significantly larger from the back, axillae, and feet in individuals from the high-temperature and high-humidity environment as compared to the moderate-temperature, low-humidity environment. High humidity and low temperature had no significant effect on total populations, but this group showed a higher frequency of isolation of fungi, and gram-negative bacteria from the back and feet. Although there was an indication that increase in the environmental humidity could result in an increased frequency of isolation of gram-negative bacteria, there was no evidence that an increase in either temperature or humidity altered the relative proportions of gram-negative bacteria in the predominantly gram-positive microbial flora found on normal skin. It was concluded that, although climatic changes may cause fluctation in microbial populations from certain sites, they are not a major influence on the ecology of the microbial flora of normal skin in the natural environment. The variables introduced by studying individuals in their natural environment and the influence of these on the results are discussed. PMID:16345214

Temperature deviation index and elderly mortality in Japan.

PubMed

Lim, Youn-Hee; Reid, Colleen E; Honda, Yasushi; Kim, Ho

2016-07-01

Few studies have examined how the precedence of abnormal temperatures in previous neighboring years affects the population's health. In the present study, we attempted to quantify the health effects of abnormal weather patterns by creating a metric called the temperature deviation index (TDI) and estimated the effects of TDI on mortality in Japan. We used data from 47 prefectures in Japan to compute the TDI on days between May and September from 1966 to 2010. The TDI is a summed product of an indicator of absence of high temperatures in the neighboring years, and more weights were assigned to the years closest to the current year. To estimate the TDI effects on elderly mortality, we used generalized linear modeling with a Poisson distribution after adjusting for apparent temperature, barometric pressure, day of the week, and time trend. For each prefecture, we estimated the TDI effects and pooled the estimates to yield a national average for 1991-2010 in Japan. The estimated effects of TDI in middle- or high-latitude prefectures were greater than in low-latitude prefectures. The estimated national average of TDI effects was a 0.5 % (95 % confidence intervals [CI], 0.1, 1.0) increase in elderly mortality per 1-unit (around 1 standard deviation) increase in the TDI. The significant pooled estimation of TDI effects was mainly due to the TDI effects on summer days with moderate temperature (25th-49th percentile, mean temperature 22.9 °C): a 1.9 % (95 % CI, 1.1, 2.6) increase in elderly mortality per 1-unit increase in the TDI. However, TDI effects were insignificant in other temperature ranges. These findings suggest that elderly deaths increased on moderate temperature days in the summer that differed substantially from days during that time window in the neighboring years. Therefore, not only high temperature itself but also temperature deviation compared to previous years could be considered to be a risk factor for elderly mortality in the summer.

Strengthening silicon carbide by quenching

NASA Technical Reports Server (NTRS)

Gruver, R. M.; Platts, D. R.; Kirchner, H. P.

1974-01-01

Quenching was used to form compressive surface layers in hot-pressed silicon carbide. The presence of the compressive stresses was verified by slotted rod tests. The slotted rod tip deflection was retained at temperatures to at least 1380 C, showing that the stresses are not relieved immediately at elevated temperatures. The flexural strength and impact resistance of specimens quenched from moderate temperatures (2000 C) were increased. Frequently, specimens quenched from higher temperatures were weakened by thermal shock damage.

Modification of meta-iodobenzylguanidine uptake in neuroblastoma cells by elevated temperature.

PubMed Central

Armour, A.; Mairs, R. J.; Gaze, M. N.; Wheldon, T. E.

1994-01-01

Successful imaging or treatment of neuroblastoma with 131I-meta-iodobenzylguanidine (131I-mIBG) depends on the selectivity of active (type 1) uptake of mIBG in neuroblastoma cells relative to passive (type 2) uptake present in most normal tissues. This study investigates the effects of moderately elevated temperature (39-41 degrees C) on the cellular uptake of 131I-mIBG in two neuroblastoma cell lines [SK-N-BE(2c) and IMR-32] and in a non-neuronal (ovarian carcinoma) cell line (A2780). In SK-N-BE(2c), a cell line with high active uptake capacity, the specific (type 1) uptake was reduced by 75% (P < 0.001) at 39 degrees C. Both IMR-32 and A2780 have a low capacity for accumulation of mIBG by active uptake. These cell lines demonstrated a statistically significant increase in accumulation at 39 degrees C, mainly as a result of increased non-specific transport. At 41 degrees C uptake of 131I-mIBG was reduced in all cell lines. Thus, the active component of mIBG uptake is more vulnerable to increased temperature than the passive component. It seems probable that moderately increased temperature will have an unfavourable effect on the therapeutic differential for targeted radiotherapy of neuroblastoma using radiolabelled mIBG. PMID:8080728

Estimating cumulative effects of clearcutting on stream temperatures

USGS Publications Warehouse

Bartholow, J.M.

2000-01-01

The Stream Segment Temperature Model was used to estimate cumulative effects of large-scale timber harvest on stream temperature. Literature values were used to create parameters for the model for two hypothetical situations, one forested and the other extensively clearcut. Results compared favorably with field studies of extensive forest canopy removal. The model provided insight into the cumulative effects of clearcutting. Change in stream shading was, as expected, the most influential factor governing increases in maximum daily water temperature, accounting for 40% of the total increase. Altered stream width was found to be more influential than changes to air temperature. Although the net effect from clearcutting was a 4oC warming, increased wind and reduced humidity tended to cool the stream. Temperature increases due to clearcutting persisted 10 km downstream into an unimpacted forest segment of the hypothetical stream, but those increases were moderated by cooler equilibrium conditions downstream. The model revealed that it is a complex set of factors, not single factors such as shade or air temperature, that governs stream temperature dynamics.

Effects of Thermal Status on Markers of Blood Coagulation During Simulated Hemorrhage

DTIC Science & Technology

2016-04-01

consumption would further reduce LBNP tolerance in the presence of moderate skin temperatures (35°C). Against our expectations, LBNP tolerance was not...exerted an effect sufficient in magnitude to mask any further impairments induced by additional dehydration and increases in body temperature ...Ventilatory parameters ( ventilation , tidal volume and breathing rate) were measured (body temperature and pressure saturated) using an automated gas

Increase in body temperature during migraine attacks.

PubMed

Ordás, Carlos M; Cuadrado, María L; Rodríguez-Cambrón, Ana B; Casas-Limón, Javier; del Prado, Náyade; Porta-Etessam, Jesús

2013-08-01

Intermittent fever has been occasionally related to migraine, either as a migraine equivalent or as a migraine accompaniment. We present a case of recurrent increase in body temperature consistently associated with migraine headaches. A 15-year-old girl reported a 3-year lasting history of migraine without aura, with a feeling of warmth occurring in each episode. Ancillary tests did not show any evidence of secondary headaches or any systemic disease. A 2-month headache diary was obtained, with daily records of headache intensity (0, no headache; 1, mild pain; 2, moderate pain; 3, severe pain) and simultaneous measurements of axillary temperature. Both parameters were registered in the evening, at 6:00 pm every day. The distribution of headache intensity and body temperature as well as the relationship between both variables over time were analyzed with nonparametric tests. The number of days without pain was 28 (45.2%); a mild headache was present on 13 days (21%), a moderate headache on 15 days (24.2%), and a severe headache on 6 days (9.7%). Headache days were associated with higher body temperature than headache-free days (median values: 37.3°C vs 36.6°C; Mann-Whitney U-test, P < 0.001). Moreover, a positive correlation was found between headache intensity and body temperature (Spearman's rho coefficient: 0.83, P < 0.001). Recurrent increase in body temperature may be another manifestation of the complex clinical spectrum of migraine. This symptom is probably related to hypothalamic involvement. Wiley Periodicals, Inc.

The impact of a moderate chronic temperature increase on spleen immune-relevant gene transcription depends on whether Atlantic cod (Gadus morhua) are stimulated with bacterial versus viral antigens.

PubMed

Hori, Tiago S; Gamperl, A Kurt; Nash, Gord; Booman, Marije; Barat, Ashoktaru; Rise, Matthew L

2013-10-01

Exposure to elevated temperature is an inherent feature of Atlantic cod (Gadus morhua) sea-cage culture in some regions (e.g., Newfoundland) and may also become an increasingly prevalent challenge for wild fish populations because of accelerated climate change. Therefore, understanding how elevated temperatures impacts the immune response of this commercially important species may help to reduce the potential negative impacts of such challenges. Previously, we investigated the impacts of moderately elevated temperature on the antiviral responses of Atlantic cod (Hori et al. 2012) and reported that elevated temperature modulated the spleen transcriptome response to polyriboinosinic polyribocytidylic acid (pIC, a viral mimic). Herein, we report a complementary microarray study that investigated the impact of the same elevated temperature regime on the Atlantic cod spleen transcriptome response to intraperitoneal (IP) injection of formalin-killed Aeromonas salmonicida (ASAL). Fish were held at two different temperatures (10 °C and 16 °C) prior to immune stimulation and sampled 6 and 24 h post-injection (HPI). In this experiment, we identified 711 and 666 nonredundant ASAL-responsive genes at 6HPI and 24HPI, respectively. These included several known antibacterial genes, including hepcidin, cathelicidin, ferritin heavy subunit, and interleukin 8. However, we only identified 15 differentially expressed genes at 6HPI and 2 at 24HPI (FDR 1%) when comparing ASAL-injected fish held at 10 °C versus 16 °C. In contrast, the same comparisons with pIC-injected fish yielded 290 and 339 differentially expressed genes (FDR 1%) at 6HPI and 24HPI, respectively. These results suggest that moderately elevated temperature has a lesser effect on the Atlantic cod spleen transcriptome response to ASAL (i.e., the antibacterial response) than to pIC (i.e., antiviral response). Thus, the impacts of high temperatures on the cod's immune response may be pathogen dependent.

Influence of disorder on the superconducting critical temperature in indium-opal nanocomposites

NASA Astrophysics Data System (ADS)

Zakharchuk, I.; Januzaj, A.; Mikhailin, N. Yu.; Traito, K. B.; Chernyaev, A. V.; Romanov, S. G.; Safonchik, M.; Shamshur, D. V.; Lähderanta, E.

2018-06-01

Transport properties of bulk indium-opal and indium-porous glass superconducting nanocomposites possessing moderate and strong disorder are investigated. A strongly nonmonotonous dependence of the global critical temperature Tc versus normal state conductivity of samples is found. The maximum, which is observed at moderate disorder, has Tc higher than that of clean bulk indium. The increasing part can be explained by the Eliashberg equations with disorder and an additional mechanism of interaction between superconducting and dielectric granules. The descending part of the maximum at higher disorder can be explained by the increasing of long-range Coulomb repulsion due to diffusion of charges. Negative slope in magnetic field dependence of resistivity and a peak in the temperature dependence of resistivity, observed in the sample near the proximity to the disorder-induced superconductor-insulator transition (SIT). A large difference between the onset temperature of superconducting fluctuations, Tcon , and global critical temperature Tc is found and considered in the framework of the weak multifractal theory. Slow time-logarithmic relaxation of the resistivity between Tc and Tcon is observed, which assumes existence of the precursor state near the SIT. This unusual state is discussed in the scope of the many-body localization theory.

Effects of high hydrostatic pressure and temperature increase on Escherichia coli spp. and pectin methyl esterase inactivation in orange juice.

PubMed

Torres, E F; González-M, G; Klotz, B; Rodrigo, D

2016-03-01

The aim of this study was to evaluate the effect of high hydrostatic pressure treatment combined with moderate processing temperatures (25 ℃-50 ℃) on the inactivation of Escherichia coli O157: H7 (ATCC 700728), E. coli K12 (ATCC 23716), and pectin methyl esterase in orange juice, using pressures of 250 to 500 MPa with times ranging between 1 and 30 min. Loss of viability of E. coli O157:H7 increased significantly as pressure and treatment time increased, achieving a 6.5 log cycle reduction at 400 MPa for 3 min at 25 ℃ of treatment. With regard to the inactivation of pectin methyl esterase, the greatest reduction obtained was 90.05 ± 0.01% at 50 ℃ and 500 MPa of pressure for 15 min; therefore, the pectin methyl esterase enzyme was highly resistant to the treatments by high hydrostatic pressure. The results obtained in this study showed a synergistic effect between the high pressure and moderate temperatures in inactivating E. coli cells. © The Author(s) 2016.

Brain temperature effects of intravenous heroin: State dependency, environmental modulation, and the effects of dose.

PubMed

Bola, R Aaron; Kiyatkin, Eugene A

2017-11-01

Here we examined how intravenous heroin at a dose that maintains self-administration (0.1 mg/kg) affects brain temperature homeostasis in freely moving rats under conditions that seek to mimic some aspects of human drug use. When administered under standard laboratory conditions (quiet rest at 22 °C ambient temperature), heroin induced moderate temperature increases (1.0-1.5 °C) in the nucleus accumbens (NAc), a critical structure of the brain motivation-reinforcement circuit. By simultaneously recording temperatures in the temporal muscle and skin, we demonstrate that the hyperthermic effects of heroin results primarily from inhibition of heat loss due to strong and prolonged skin vasoconstriction. Heroin-induced brain temperature increases were enhanced during behavioral activation (i.e., social interaction) and in a moderately warm environment (29 °C). By calculating the "net" effects of the drug in these two conditions, we found that this enhancement results from the summation of the hyperthermic effects of heroin with similar effects induced by either social interaction or a warmer environment. When the dose of heroin was increased (to 0.2, 0.4, 0.8, 1.6, 3.2, and 6.4 mg/kg), brain temperature showed a biphasic down-up response. The initial temperature decrease was dose-dependent and resulted from a transient inhibition of intra-brain heat production coupled with increased heat loss via skin surfaces-the effects typically induced by general anesthetics. These initial inhibitory effects induced by large-dose heroin injections could be related to profound CNS depression-the most serious health complications typical of heroin overdose in humans. Published by Elsevier Ltd.

Escherichia coli inactivation kinetics in anaerobic digestion of dairy manure under moderate, mesophilic and thermophilic temperatures

PubMed Central

2011-01-01

Batch anaerobic digestion experiments using dairy manure as feedstocks were performed at moderate (25°C), mesophilic (37°C), and thermophilic (52.5°C) temperatures to understand E. coli, an indicator organism for pathogens, inactivation in dairy manure. Incubation periods at 25, 37, and 52.5°C, were 61, 41, and 28 days respectively. Results were used to develop models for predicting E. coli inactivation and survival in anaerobic digestion. For modeling we used the decay of E. coli at each temperature to calculate the first-order inactivation rate coefficients, and these rates were used to formulate the time - temperature - E. coli survival relationships. We found the inactivation rate coefficient at 52.5°C was 17 and 15 times larger than the inactivation rate coefficients at 25 and 37°C, respectively. Decimal reduction times (D10; time to achieve one log removal) at 25, 37, and 52.5°C, were 9 -10, 7 - 8 days, and < 1 day, respectively. The Arrhenius correlation between inactivation rate coefficients and temperatures over the range 25 -52.5°C was developed to understand the impacts of temperature on E. coli inactivation rate. Using this correlation, the time - temperature - E. coli survival relationships were derived. Besides E. coli inactivation, impacts of temperature on biogas production, methane content, pH change, ORP, and solid reduction were also studied. At higher temperatures, biogas production and methane content was greater than that at low temperatures. While at thermophilic temperature pH was increased, at mesophilic and moderate temperatures pH were reduced over the incubation period. These results can be used to understand pathogen inactivation during anaerobic digestion of dairy manure, and impacts of temperatures on performance of anaerobic digesters treating dairy manure. PMID:21906374

Chlorophyll fluorescence and CO(2) assimilation of black spruce seedlings following frost in different temperature and light conditions.

PubMed

Lamontagne, M.; Bigras, F. J.; Margolis, H. A.

2000-03-01

Effects of artificial frosts on light-saturated photosynthesis (A(max)) and ground, maximal and variable fluorescence variables (F(o), F(m), and F(v) and F(v)/F(m)) were monitored on 1-year-old foliage of black spruce seedlings (Picea mariana (Mill.) BSP) grown at high (25 degrees C), moderate (15 degrees C) and low (5 degrees C) temperatures and moderate (240 &mgr;mol m(-2) s(-1)) and low (80 &mgr;mol m(-2) s(-1)) irradiances. Photoinhibition of 1-year-old foliage was greater in seedlings grown in moderate light than in seedlings grown in low light. Photoinhibition increased with decreasing growth chamber temperature at both irradiances. Most changes in F(v)/F(m) were caused by changes in F(v). Exposure to -4 degrees C decreased both F(v)/F(m) and A(max) compared with control values. The effect of the -4 degrees C frost treatment was greater in seedlings grown in low light than in seedlings grown in moderate light, probably because seedlings grown in moderate light were already partially photoinhibited before the frost treatment. Following -4 degrees C treatment, neither F(v)/F(m) nor A(max) recovered in seedlings grown in low light. Light-saturated photosynthesis decreased with decreasing growth chamber temperature. Light-saturated photosynthesis was more sensitive to the -3 and -4 degrees C frost treatments in seedlings grown at 25 degrees C than in seedlings grown at 15 and 5 degrees C. The A(max) of seedlings grown at 15 degrees C was sensitive only to the -4 degrees C frost treatment, whereas A(max) of seedlings grown at 5 degrees C was not sensitive to any of the frost treatments. Recovery of A(max) following frost took longer in seedlings grown at high temperatures than in seedlings grown at low temperatures. For seedlings grown at the same temperature but under different irradiances, both A(max) and F(v)/F(m) reflected damage to the photosynthetic system following a moderate frost. However, for seedlings grown at the same irradiance but different temperatures, A(max) provided a more sensitive indicator of frost damage to the photosynthetic system than F(v)/F(m) ratio.

Extracellular hyperosmolality and body temperature during physical exercise in dogs

NASA Technical Reports Server (NTRS)

Kozlowski, S.; Greenleaf, J. E.; Turlejska, E.; Nazar, K.

1980-01-01

The purpose of this study was to test the hypothesis that thermoregulation during exercise can be affected by extracellular fluid hyperosmolality without changing the plasma Na(+) concentration. The effects of preexercise venous infusions of hypertonic mannitol and NaCl solutions on rectal temperature responses were compared in dogs running at moderate intensity for 60 min on a treadmill. Plasma Na(+) concentration was increased by 12 meq after NaCl infusion, and decreased by 9 meq after mannitol infusion. Both infusions increased plasma by 15 mosmol/kg. After both infusions, rectal temperature was essentially constant during 60 min rest. However, compared with the noninfusion exercise increase in osmolality of 1.3 C, rectal temperature increased by 1.9 C after both postinfusion exercise experiments. It was concluded that inducing extracellular hyperosmolality, without elevating plasma, can induce excessive increases in rectal temperature during exericse but not at rest.

Enhancement of oxygen transfer and nitrogen removal in a membrane separation bioreactor for domestic wastewater treatment.

PubMed

Chiemchaisri, C; Yamamoto, K

2005-01-01

Biological nitrogen removal in a membrane separation bioreactor developed for on-site domestic wastewater treatment was investigated. The bioreactor employed hollow fiber membrane modules for solid-liquid separation so that the biomass could be completely retained within the system. Intermittent aeration was supplied with 90 minutes on and off cycle to achieve nitrification and denitrification reaction for nitrogen removal. High COD and nitrogen removal of more than 90% were achieved under a moderate temperature of 25 degrees C. As the temperature was stepwise decreased from 25 to 5 degrees C, COD removal in the system could be constantly maintained while nitrogen removal was deteriorated. Nevertheless, increasing aeration supply could enhance nitrification at low temperature with benefit from complete retention of nitrifying bacteria within the system by membrane separation. At low operating temperature range of 5 degrees C, nitrogen removal could be recovered to more than 85%. A mathematical model considering diffusion resistance of limiting substrate into the bio-particle is applied to describe nitrogen removal in a membrane separation bioreactor. The simulation suggested that limitation of the oxygen supply was the major cause of inhibition of nitrification during temperature decrease. Nevertheless, increasing aeration could promote oxygen diffusion into the bio-particle. Sufficient oxygen was supplied to the nitrifying bacteria and the nitrification could proceed. In the membrane separation bioreactor, biomass concentration under low temperature operation was allowed to increase by 2-3 times of that of moderate temperature to compensate for the loss of bacterial activities so that the temperature effect was masked.

Behavior of a PCM at Varying Heating Rates: Experimental and Theoretical Study with an Aim at Temperature Moderation in Radionuclide Concrete Encasements

NASA Astrophysics Data System (ADS)

Medved', Igor; Trník, Anton

2018-07-01

Phase-change materials (PCMs) can store/release thermal energy within a small temperature range. This is of interest in various industrial applications, for example, in civil engineering (heating/cooling of buildings) or cold storage applications. Another application may be the moderation of temperature increases in concrete encasements of radionuclides during their decay. The phase-change behavior of a material is determined by its heat capacity and the peak it exhibits near a phase change. We analyze the behavior of such peaks for a selected PCM at heating rates varying between 0.1°C\\cdot min^{-1} and 1°C\\cdot min^{-1}, corresponding in real situations to different decay rates of radionuclides. We show that experimentally measured peaks can be plausibly described by an equilibrium theory that enables us to calculate the latent heat and phase-change temperature from experimental data.

Effect of Heat Treatment Parameters on the Microstructure and Properties of Inconel-625 Superalloy

NASA Astrophysics Data System (ADS)

Sukumaran, Arjun; Gupta, R. K.; Anil Kumar, V.

2017-07-01

Inconel-625 is a solid solution-strengthened alloy used for long-duration applications at high temperatures and moderate stresses. Different heat treatment cycles (temperatures of 625-1025 °C and time of 2-6 h) have been studied to obtain optimum mechanical properties suitable for a specific application. It has been observed that room temperature strength and, hardness decreased and ductility increased with increase in heat treatment temperature. The rate of change of these properties is found to be moderate for the samples heat-treated up to 850 °C, and thereafter, it increases rapidly. It is attributed to the microstructural changes like dissolution of carbides, recrystallization and grain growth. Microstructures are found to be predominantly single-phase austenitic with the presence of fine alloy carbides. The presence of twins is observed in samples heat-treated at lower temperature, which act as nucleation sites for recrystallization at 775 °C. Beyond 850 °C, the role of carbides present in the matrix is subsided by the coarsening of recrystallized grains and finally at 1025 °C, significant dissolution of carbide results in substantial reduction in strength and increase in ductility. Elongation to an extent of >71% has been obtained in sample heat-treated at 1025 °C indicating excellent tendency for cold workability. Failure of heat-treated specimens is found to be mainly due to carbide particle-matrix decohesion which acts as locations for crack initiation.

TiO2 film properties as a function of processing temperature, volume 3

NASA Technical Reports Server (NTRS)

Fitzgibbons, E. T.; Sladek, K. J.; Hartwig, W. H.

1972-01-01

Thin film TiO2 was produced at 150 C by chemical vapor deposition using hydrolysis of tetraisopropyl titanate. Films were amorphous as grown, but annealing in air caused crystallization, with anatase formed beginning at 350 C and rutile at 700 C. Density and index of refraction increased substantially with increasing anneal temperature, while etch susceptibility in HF and H2SO4 decreased. Comparison with literature data showed two groups of processes. One group yields films having properties that gradually approach those of rutile with increasing process temperature. The other group gives rutile directly at moderate temperatures. Deposition of amorphous film followed by etching and annealing is suggested as a means for pattern definition.

Effect of molasses in anaerobic soil disinfestation: Focus on the soil microbiome

USDA-ARS?s Scientific Manuscript database

Growers in Florida have begun to apply molasses to increase the soil microbial biodiversity. Previous reports have indicated that a greater microbial diversity could cause disease suppressive soils. Furthermore, it has been shown that under moderate temperature, 15-20° C, an increase of carbon could...

Modulation of fatty acid composition and growth in Sporosarcina species in response to temperatures and exogenous branched-chain amino acids.

PubMed

Tsuda, Kentaro; Nagano, Hideaki; Ando, Akinori; Shima, Jun; Ogawa, Jun

2017-06-01

Psychrotolerant endospore-forming Sporosarcina species have been predominantly isolated from minced fish meat (surimi), which is stored under refrigeration after heat treatment. To develop a better method for preserving surimi-based food products, we studied the growth and fatty acid compositions of the isolated strain S92h as well as Sporosarcina koreensis and Sporosarcina aquimarina at cold and moderate temperatures. The growth rates of strain S92h and S. koreensis were the fastest and slowest at cold temperatures, respectively, although these strains grew at a similar rate at moderate temperatures. In all three strains, the proportions of anteiso-C 15:0 and unsaturated fatty acids (UFAs) were significantly higher at cold temperatures than at moderate temperatures. Furthermore, supplementation with valine, leucine, and isoleucine resulted in proportional increases in iso-C 16:0 , iso-C 15:0 , and anteiso-C 15:0 , respectively, among the fatty acid compositions of these strains. The proportions of the UFAs were also altered by the supplementation. At cold temperatures, the growth rates of strain S92h and S. koreensis, but not of S. aquimarina, were affected by supplementation with leucine. Supplementation with isoleucine enhanced the growth of S. koreensis at cold temperatures but not that of the other strains. Valine did not affect the growth of any strain. These results indicate that anteiso-C 15:0 and UFAs both play important roles in the cold tolerance of the genus Sporosarcina and that these bacteria modulate their fatty acid compositions in response to the growth environment.

Testing the impact of virus importation rates and future climate change on dengue activity in Malaysia using a mechanistic entomology and disease model.

PubMed

Williams, C R; Gill, B S; Mincham, G; Mohd Zaki, A H; Abdullah, N; Mahiyuddin, W R W; Ahmad, R; Shahar, M K; Harley, D; Viennet, E; Azil, A; Kamaluddin, A

2015-10-01

We aimed to reparameterize and validate an existing dengue model, comprising an entomological component (CIMSiM) and a disease component (DENSiM) for application in Malaysia. With the model we aimed to measure the effect of importation rate on dengue incidence, and to determine the potential impact of moderate climate change (a 1 °C temperature increase) on dengue activity. Dengue models (comprising CIMSiM and DENSiM) were reparameterized for a simulated Malaysian village of 10 000 people, and validated against monthly dengue case data from the district of Petaling Jaya in the state of Selangor. Simulations were also performed for 2008-2012 for variable virus importation rates (ranging from 1 to 25 per week) and dengue incidence determined. Dengue incidence in the period 2010-2012 was modelled, twice, with observed daily weather and with a 1 °C increase, the latter to simulate moderate climate change. Strong concordance between simulated and observed monthly dengue cases was observed (up to r = 0·72). There was a linear relationship between importation and incidence. However, a doubling of dengue importation did not equate to a doubling of dengue activity. The largest individual dengue outbreak was observed with the lowest dengue importation rate. Moderate climate change resulted in an overall decrease in dengue activity over a 3-year period, linked to high human seroprevalence early on in the simulation. Our results suggest that moderate reductions in importation with control programmes may not reduce the frequency of large outbreaks. Moderate increases in temperature do not necessarily lead to greater dengue incidence.

Impact of synovial fluid flow on temperature regulation in knee cartilage.

PubMed

Moghadam, Mohamadreza Nassajian; Abdel-Sayed, Philippe; Camine, Valérie Malfroy; Pioletti, Dominique P

2015-01-21

Several studies have reported an increase of temperature in cartilage submitted to cyclic sinusoidal loading. The temperature increase is in part due to the viscous behavior of this tissue, which partially dissipates the input mechanical energy into heat. While the synovial fluid flow within the intra-articular gap and inside the porous cartilage is supposed to play an important role in the regulation of the cartilage temperature, no specific study has evaluated this aspect. In the present numerical study, a poroelastic model of the knee cartilage is developed to evaluate first the temperature increase in the cartilage due to dissipation and second the impact of the synovial fluid flow in the cartilage heat transfer phenomenon. Our results showed that, the local temperature is effectively increased in knee cartilage due to its viscous behavior. The synovial fluid flow cannot significantly preventing this phenomenon. We explain this result by the low permeability of cartilage and the moderate fluid exchange at the surface of cartilage under deformation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Oxidation kinetics of hydride-bearing uranium metal corrosion products

NASA Astrophysics Data System (ADS)

Totemeier, Terry C.; Pahl, Robert G.; Frank, Steven M.

The oxidation behavior of hydride-bearing uranium metal corrosion products from Zero Power Physics Reactor (ZPPR) fuel plates was studied using thermo-gravimetric analysis (TGA) in environments of Ar-4%O 2, Ar-9%O 2, and Ar-20%O 2. Ignition of corrosion product samples from two moderately corroded plates was observed between 125°C and 150°C in all environments. The rate of oxidation above the ignition temperature was found to be dependent only on the net flow rate of oxygen in the reacting gas. Due to the higher net oxygen flow rate, burning rates increased with increasing oxygen concentration. Oxidation rates below the ignition temperature were much slower and decreased with increasing test time. The hydride contents of the TGA samples from the two moderately corroded plates, determined from the total weight gain achieved during burning, were 47-61 wt% and 29-39 wt%. Samples from a lightly corroded plate were not reactive; X-ray diffraction (XRD) confirmed that they contained little hydride.

Potential fitness trade-offs for thermal tolerance in the intertidal copepod Tigriopus californicus.

PubMed

Willett, Christopher S

2010-09-01

Thermal adaptation to spatially varying environmental conditions occurs in a wide range of species, but what is less clear is the nature of fitness trade-offs associated with this temperature adaptation. Here, populations of the intertidal copepod Tigriopus californicus are examined at both local and latitudinal scales to determine whether these populations have evolved differences in their survival under high temperature stress. A clear pattern of increasing high temperature stress tolerance is seen with decreasing latitude, consistent with temperature adaptation. Additionally, there is also evidence for significant variation in thermal tolerance on a smaller scale. The competitive fitness of pairs of northern and southern copepod populations were also examined under a series of lower, more moderate temperatures. These fitness assays show that the southern populations that have the best survival under extreme high temperatures have lowered competitive fitness at the lower temperatures tested, whereas the fitness of the southern populations exceeded that of the northern populations at the highest temperatures tested. Combined, these results suggest that there may be evolutionary trade-offs between performance at high and stressful temperatures and fitness at moderate temperatures in this species. © 2010 The Author(s). Journal compilation © 2010 The Society for the Study of Evolution.

Effects of incubation temperature on growth and performance of the veiled chameleon (Chamaeleo calyptratus).

PubMed

Andrews, Robin M

2008-10-01

I evaluated the effect of incubation temperature on phenotypes of the veiled chameleon, Chamaeleo calyptratus. I chose this species for study because its large clutch size (30-40 eggs or more) allows replication within clutches both within and among experimental treatments. The major research objectives were (1) to assess the effect of constant low, moderate, and high temperatures on embryonic development, (2) to determine whether the best incubation temperature for embryonic development also produced the "best" hatchlings, and (3) to determine how a change in incubation temperature during mid-development would affect phenotype. To meet these objectives, I established five experimental temperature regimes and determined egg survival and incubation length and measured body size and shape, selected body temperatures, and locomotory performance of lizards at regular intervals from hatching to 90 d, or just before sexual maturity. Incubation temperature affected the length of incubation, egg survival, and body mass, but did not affect sprint speed or selected body temperature although selected body temperature affected growth in mass independently of treatment and clutch. Incubation at moderate temperatures provided the best conditions for both embryonic and post-hatching development. The highest incubation temperatures were disruptive to development; eggs had high mortality, developmental rate was low, and hatchlings grew slowly. Changes in temperature during incubation increased the among-clutch variance in incubation length relative to that of constant temperature treatments. Copyright 2008 Wiley-Liss, Inc.

Paraheliotropic leaf movement in Siratro as a protective mechanism against drought-induced damage to primary photosynthetic reactions: damage by excessive light and heat.

PubMed

Ludlow, M M; Björkman, O

1984-11-01

Damage to primary photosynthetic reactions by drought, excess light and heat in leaves of Macroptilium atropurpureum Dc. cv. Siratro was assessed by measurements of chlorophyll fluorescence emission kinetics at 77 K (-196°C). Paraheliotropic leaf movement protected waterstressed Siratro leaves from damage by excess light (photoinhibition), by heat, and by the interactive effects of excess light and high leaf temperatures. When the leaves were restrained to a horizontal position, photoinhibition occurred and the degree of photoinhibitory damage increased with the time of exposure to high levels of solar radiation. Severe inhibition was followed by leaf death, but leaves gradually recovered from moderate damage. This drought-induced photoinhibitory damage seemed more closely related to low leaf water potential than to low leaf conductance. Exposure to leaf temperatures above 42°C caused damage to the photosynthetic system even in the dark and leaves died at 48°C. Between 42 and 48°C the degree of heat damage increased with the time of exposure, but recovery from moderate heat damage occurred over several days. The threshold temperature for direct heat damage increased with the growth temperature regime, but was unaffected by water-stress history or by current leaf water status. No direct heat damage occurred below 42°C, but in water-stressed plants photoinhibition increased with increasing leaf temperature in the range 31-42°C and with increasing photon flux density up to full sunglight values. Thus, water stress evidently predisposes the photosynthetic system to photoinhibition and high leaf temperature exacerbates this photoinhibitory damage. It seems probable that, under the climatic conditions where Siratro occurs in nature, but in the absence of paraheliotropic leaf movement, photoinhibitory damage would occur more frequently during drought than would direct heat damage.

Risk of mortality associated with neonatal hypothermia in southern Nepal.

PubMed

Mullany, Luke C; Katz, Joanne; Khatry, Subarna K; LeClerq, Steven C; Darmstadt, Gary L; Tielsch, James M

2010-07-01

To quantify the neonatal mortality/hypothermia relationship and develop evidence-based cutoffs for global definitions of neonatal hypothermia. Cohort study. Field workers recorded neonatal axillary temperature at home and recorded vital status at 28 days. Rural Nepal. Twenty-three thousand two hundred forty infants in Sarlahi, Nepal. Hypothermia. Mortality risk was estimated using binomial regression models. Infants were classified using (1) World Health Organization (WHO) cutoffs for mild, moderate, and severe hypothermia; (2) quarter-degree intervals from 32.0 degrees C to 36.5 degrees C; and (3) continuous temperatures. Estimates were adjusted for age, ambient temperature, and other potential confounders. Mortality increased among mild (relative risk [RR], 1.70; 95% confidence interval [CI], 1.23-2.35]), moderate (RR, 4.66; 95% CI, 3.47-6.24]), and severe (RR, 23.36; 95% CI, 4.31-126.70]) hypothermia cases. Within the WHO's moderate classification, risk relative to normothermic infants ranged from 2 to 30 times. Adjusted mortality risk increased 80% (95% CI, 63%-100%) for each degree decrease, was strongly associated with temperatures below 35.0 degrees C (RR, 6.11; 95% CI, 3.98-9.38), and was substantially higher among preterm infants (RR, 12.02; 95% CI, 6.23-23.18]) compared with full-term infants (RR, 3.12; 95% CI, 1.75-5.57). Relative risk was highest in the first 7 days, but remained elevated through 28 days. A new hypothermia classification system should be considered by the WHO for global guidelines. We recommend that grade 1 be equivalent to the current mild category (36.0 degrees C), restricting and splitting the moderate category into grades 2 (35.0 degrees C-36.0 degrees C) and 3 (34.0 degrees C-35.0 degrees C), and expanding severe hypothermia to less than 34.0 degrees C (grade 4). Reducing hypothermia may dramatically decrease the global neonatal mortality burden.

Brassinosteroid signaling-dependent root responses to prolonged elevated ambient temperature.

PubMed

Martins, Sara; Montiel-Jorda, Alvaro; Cayrel, Anne; Huguet, Stéphanie; Roux, Christine Paysant-Le; Ljung, Karin; Vert, Grégory

2017-08-21

Due to their sessile nature, plants have to cope with and adjust to their fluctuating environment. Temperature elevation stimulates the growth of Arabidopsis aerial parts. This process is mediated by increased biosynthesis of the growth-promoting hormone auxin. How plant roots respond to elevated ambient temperature is however still elusive. Here we present strong evidence that temperature elevation impinges on brassinosteroid hormone signaling to alter root growth. We show that elevated temperature leads to increased root elongation, independently of auxin or factors known to drive temperature-mediated shoot growth. We further demonstrate that brassinosteroid signaling regulates root responses to elevated ambient temperature. Increased growth temperature specifically impacts on the level of the brassinosteroid receptor BRI1 to downregulate brassinosteroid signaling and mediate root elongation. Our results establish that BRI1 integrates temperature and brassinosteroid signaling to regulate root growth upon long-term changes in environmental conditions associated with global warming.Moderate heat stimulates the growth of Arabidopsis shoots in an auxin-dependent manner. Here, Martins et al. show that elevated ambient temperature modifies root growth by reducing the BRI1 brassinosteroid-receptor protein level and downregulating brassinosteroid signaling.

Interaction Effects of Temperature and Ozone on Lung Function and Markers of Systemic Inflammation, Coagulation, and Fibrinolysis: A Crossover Study of Healthy Young Volunteers

PubMed Central

Kahle, Juliette J.; Neas, Lucas M.; Devlin, Robert B.; Case, Martin W.; Schmitt, Michael T.; Madden, Michael C.

2014-01-01

Background: Trends in climate suggest that extreme weather events such as heat waves will become more common. High levels of the gaseous pollutant ozone are associated with elevated temperatures. Ozone has been associated with respiratory diseases as well as cardiovascular morbidity and mortality and can reduce lung function and alter systemic markers of fibrinolysis. The interaction between ozone and temperature is unclear. Methods: Sixteen healthy volunteers were exposed in a randomized crossover study to 0.3 ppm ozone and clean air for 2 hr at moderate (22°C) temperature and again at an elevated temperature (32.5°C). In each case lung function was performed and blood taken before and immediately after exposure and the next morning. Results: Ozone exposure at 22°C resulted in a decrease in markers of fibrinolysis the next day. There was a 51.8% net decrease in PAI-1 (plasminogen activator inhibitor-1), a 12.1% net decrease in plasminogen, and a 17.8% net increase in D-dimer. These significantly differed from the response at 32.5°C, where there was a 44.9% (p = 0.002) and a 27.9% (p = 0.001) increase in PAI-1 and plasminogen, respectively, and a 12.5% (p = 0.042) decrease in D-dimer. In contrast, decrements in lung function following ozone exposure were comparable at both moderate and elevated temperatures (forced expiratory volume in 1 sec, –12.4% vs. –7.5%, p > 0.05). No changes in systemic markers of inflammation were observed for either temperature. Conclusion: Ozone-induced systemic but not respiratory effects varied according to temperature. Our study suggests that at moderate temperature ozone may activate the fibrinolytic pathway, while at elevated temperature ozone may impair it. These findings provide a biological basis for the interaction between temperature and ozone on mortality observed in some epidemiologic studies. Citation: Kahle JJ, Neas LM, Devlin RB, Case MW, Schmitt MT, Madden MC, Diaz-Sanchez D. 2015. Interaction effects of temperature and ozone on lung function and markers of systemic inflammation, coagulation, and fibrinolysis: a crossover study of healthy young volunteers. Environ Health Perspect 123:310–316; http://dx.doi.org/10.1289/ehp.1307986 PMID:25514459

Rapid down-regulation of testicular androgen biosynthesis at increased environmental temperature is due to cytochrome P450c17 (CYP17) thermolability in Leydig cells, but not in endoplasmic reticulum membranes.

PubMed

Kühn-Velten, W N

1996-01-01

To identify possible molecular targets in moderate heat-induced, short-term derangements of rat testicular endocrine function, rates of androgen and precursor biosynthesis and key enzyme concentrations were compared at 38 degrees C (normal body core temperature) and 31 degrees C (normal scrotal temperature) in three in-vitro models of decreasing complexity and increasing specificity. In purified Leydig cells and similarly in decapsulated testes, gross testosterone secretion was by 20% higher at 38 degrees C under basal conditions and during the initial phase of stimulation with hCG or cAMP; longer (> 1 hour) exposure to the elevated temperature resulted in a marked decrease (52% after 3 hours) of testosterone response to hCG or cAMP as compared to the corresponding rates at 31 degrees C. This phenomenon was neither due to the development of hormone resistance at the receptor level nor to restricted cholesterol supply and turnover nor to increased testosterone accumulation. Whereas mitochondrial CYP11A (cytochrome P450cscc: cholesterol monooxygenase) was absolutely temperature-insensitive in all systems tested, CYP17 (cytochrome P450c17: steroid-17 alpha-monooxygenase/C17, 20-aldolase) in the smooth endoplasmic reticulum responded with a 57% loss in whole testes and 39% loss in purified Leydig cells upon a 3-hour temperature elevation from 31 degrees C to 38 degrees C. In contrast, CYP17 was stable (4% loss) when tested directly in microsomal membranes. It is concluded that CYP17, but not CYP11A, is very sensitive towards even moderate elevation of environmental temperature, and that this apparent lability is not an intrinsic property of the enzyme protein but rather mediated by heat-activated intracellular factors.

Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs

PubMed Central

Edmondson, J. L.; Stott, I.; Davies, Z. G.; Gaston, K. J.; Leake, J. R.

2016-01-01

Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health. PMID:27641002

Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs.

PubMed

Edmondson, J L; Stott, I; Davies, Z G; Gaston, K J; Leake, J R

2016-09-19

Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health.

Introducing ultrasonic falling film evaporator for moderate temperature evaporation enhancement.

PubMed

Dehbani, Maryam; Rahimi, Masoud

2018-04-01

In the present study, Ultrasonic Falling Film (USFF), as a novel technique has been proposed to increase the evaporation rate of moderate temperature liquid film. It is a proper method for some applications which cannot be performed at high temperature, such as foodstuff industry, due to their sensitivity to high temperatures. Evaporation rate of sodium chloride solution from an USFF on an inclined flat plate compared to that for Falling Film without ultrasonic irradiation (FF) at various temperatures was investigated. The results revealed that produced cavitation bubbles have different effects on evaporation rate at different temperatures. At lower temperatures, size fluctuation and collapse of bubbles and in consequence induced physical effects of cavitation bubbles resulted in more turbulency and evaporation rate enhancement. At higher temperatures, the behavior was different. Numerous created bubbles joined together and cover the plate surface, so not only decreased the ultrasound vibrations but also reduced the evaporation rate in comparison with FF. The highest evaporation rate enhancement of 353% was obtained at 40 °C at the lowest Reynolds number of 250. In addition, the results reveal that at temperature of 40 °C, USFF has the highest efficiency compared to FF. Copyright © 2017 Elsevier B.V. All rights reserved.

Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs

NASA Astrophysics Data System (ADS)

Edmondson, J. L.; Stott, I.; Davies, Z. G.; Gaston, K. J.; Leake, J. R.

2016-09-01

Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health.

Lower Granite Dam Smolt Monitoring Program, 1998 Annual Report.

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

Verhey, Peter; Ross, Doug; Morrill, Charles

1998-12-01

The 1998 fish collection season at Lower Granite was characterized by relatively moderate spring flows and spill, moderate levels of debris, cool spring, warm summer and fall water temperatures, and increased chinook numbers, particularly wild subyearling chinook collected and transported. The Fish Passage Center's Smolt Monitoring Program is designed to provide a consistent, real-time database on fish passage and document the migrational characteristics of the many stocks of salmon and steelhead in the Columbia Basin.

Increasing probability of mortality during Indian heat waves.

PubMed

Mazdiyasni, Omid; AghaKouchak, Amir; Davis, Steven J; Madadgar, Shahrbanou; Mehran, Ali; Ragno, Elisa; Sadegh, Mojtaba; Sengupta, Ashmita; Ghosh, Subimal; Dhanya, C T; Niknejad, Mohsen

2017-06-01

Rising global temperatures are causing increases in the frequency and severity of extreme climatic events, such as floods, droughts, and heat waves. We analyze changes in summer temperatures, the frequency, severity, and duration of heat waves, and heat-related mortality in India between 1960 and 2009 using data from the India Meteorological Department. Mean temperatures across India have risen by more than 0.5°C over this period, with statistically significant increases in heat waves. Using a novel probabilistic model, we further show that the increase in summer mean temperatures in India over this period corresponds to a 146% increase in the probability of heat-related mortality events of more than 100 people. In turn, our results suggest that future climate warming will lead to substantial increases in heat-related mortality, particularly in developing low-latitude countries, such as India, where heat waves will become more frequent and populations are especially vulnerable to these extreme temperatures. Our findings indicate that even moderate increases in mean temperatures may cause great increases in heat-related mortality and support the efforts of governments and international organizations to build up the resilience of these vulnerable regions to more severe heat waves.

Moderate- and high-intensity exhaustive exercise in the heat induce a similar increase in monocyte Hsp72.

PubMed

Périard, J D; Ruell, P A; Thompson, M W; Caillaud, C

2015-11-01

This study examined the relationship between exhaustive exercise in the heat at moderate and high intensities on the intracellular heat shock protein 72 (iHsp72) response. Twelve male subjects cycled to exhaustion at 60 and 75% of maximal oxygen uptake in hot conditions (40 °C, 50% RH). iHsp72 concentration was measured in monocytes before, at exhaustion and 24 h after exercise. Rectal temperature, heart rate and oxygen uptake were recorded during exercise. Volitional exhaustion occurred at 58.9 ± 12.1 and 27.3 ± 9.5 min (P < 0.001) and a rectal temperature of 39.8 ± 0.4 and 39.2 ± 0.6 °C (P = 0.002), respectively, for 60 and 75 %. The area under the curve above a rectal temperature of 38.5 °C was greater at 60 % (17.5 ± 6.6 °C min) than 75 % (3.4 ± 4.8 °C min; P < 0.001), whereas the rate of increase in rectal temperature was greater at 75 % (5.1 ± 1.7 vs. 2.2 ± 1.4 °C h(-1); P < 0.001). iHsp72 concentration increased similarly at exhaustion relative to pre-exercise (P = 0.044) and then increased further at 24 h (P < 0.001). Multiple regression analysis revealed no predictor variables associated with iHsp72 expression; however, a correlation was observed between exercise intensities for the increase in iHsp expression at exhaustion and 24 h (P < 0.05). These results suggest that iHsp72 expression increased in relation to the level of hyperthermia attained and sustained at 60 % and the higher metabolic rate and greater rate of increase in core temperature at 75 %, with the further increase in iHsp72 concentration 24 h after exercise reinforcing its role as a chaperone and cytoprotective agent.

Cold and heat strain during cold-weather field training with nuclear, biological, and chemical protective clothing.

PubMed

Rissanen, Sirkka; Rintamäki, Hannu

2007-02-01

The objective of this study was to quantify the thermal strain of soldiers wearing nuclear, biological, and chemical protective clothing during short-term field training in cold conditions. Eleven male subjects performed marching exercises at moderate and heavy activity levels for 60 minutes. Rectal temperature (Tre), skin temperatures, and heart rate were monitored. Ambient temperature (Ta) varied from -33 to 0 degrees C. Tre was affected by changes in metabolism, rather than in Ta. Tre increased above 38 degrees during heavy exercise even at -33 degrees C. The mean skin temperature decreased to tolerance level (25 degrees C) at Ta below -25 degrees C with moderate exercise. Finger temperature decreased below 15 degrees C (performance degradation) at Ta of -15 degrees C or cooler. The present results from the field confirm the previous results based on laboratory studies and show that risk of both heat and cold strain is evident, with cooling of extremities being most critical, while wearing nuclear, biological, and chemical protective clothing during cold-weather training.

Impact of long-term moderate hypercapnia and elevated temperature on the energy budget of isolated gills of Atlantic cod (Gadus morhua).

PubMed

Kreiss, Cornelia M; Michael, Katharina; Bock, Christian; Lucassen, Magnus; Pörtner, Hans-O

2015-04-01

Effects of severe hypercapnia have been extensively studied in marine fishes, while knowledge on the impacts of moderately elevated CO2 levels and their combination with warming is scarce. Here we investigate ion regulation mechanisms and energy budget in gills from Atlantic cod acclimated long-term to elevated PCO2 levels (2500 μatm) and temperature (18°C). Isolated perfused gill preparations were established to determine gill thermal plasticity during acute exposures (10-22°C) and in vivo costs of Na(+)/K(+)-ATPase activity, protein and RNA synthesis. Maximum enzyme capacities of F1Fo-ATPase, H(+)-ATPase and Na(+)/K(+)-ATPase were measured in vitro in crude gill homogenates. After whole animal acclimation to elevated PCO2 and/or warming, branchial oxygen consumption responded more strongly to acute temperature change. The fractions of gill respiration allocated to protein and RNA synthesis remained unchanged. In gills of fish CO2-exposed at both temperatures, energy turnover associated with Na(+)/K(+)-ATPase activity was reduced by 30% below rates of control fish. This contrasted in vitro capacities of Na(+)/K(+)-ATPase, which remained unchanged under elevated CO2 at 10°C, and earlier studies which had found a strong upregulation under severe hypercapnia. F1Fo-ATPase capacities increased in hypercapnic gills at both temperatures, whereas Na(+)/K(+)ATPase and H(+)-ATPase capacities only increased in response to elevated CO2 and warming indicating the absence of thermal compensation under CO2. We conclude that in vivo ion regulatory energy demand is lowered under moderately elevated CO2 levels despite the stronger thermal response of total gill respiration and the upregulation of F1Fo-ATPase. This effect is maintained at elevated temperature. Copyright © 2014 Elsevier Inc. All rights reserved.

The survivability of Bacillus anthracis (Sterne strain) in processed liquid eggs.

PubMed

Khan, Saeed A; Sung, Kidon; Nawaz, Mohamed S; Cerniglia, Carl E; Tamplin, Mark L; Phillips, Robert W; Kelley, Lynda Collins

2009-04-01

In this study, we investigated the survival and inactivation kinetics of a surrogate strain of Bacillus anthracis (Sterne strain) in whole egg (WE), egg white (EW), sugared egg yolk (YSU), and salted egg yolk (YSA) at low (-20, 0, and 5 degrees C), moderate (15, 20, 25, 30, 35, and 40 degrees C), and high storage temperatures (45, 50, 55, and 60 degrees C). Outgrowth of the spores was measured as lag phase duration (LPD). Replication of vegetative cells was measured in terms of growth rate (GR) and maximum population density (MPD). Spore inactivation was recorded as inactivation rate and percent reduction in viable count. In general, spore viability decreased at low and high temperatures and increased at moderate temperatures. At 0 and 5 degrees C, a 60-100% reduction in spore viability was seen within 2-3 weeks in WE and YSU, 0-30% in YSA, and 50-100% in EW. At -20 degrees C, however, no drop in spore titer was observed in YSU and EW but a 20% drop in titer was seen in YSA and 50% in WE within 2-3 weeks. At high temperatures, WE, EW, and YSA produced a 20-50% drop in the spore titer within 1-4h whereas YSU showed 100% inactivation within 0.75 h. At moderate storage temperatures, as the temperature increased from 15 to 40 degrees C, LPD decreased from 13.5 to 0.75 h and MPD reached 0.27-2.2 x1 0(9) CFU/ml in YSU and WE, respectively. Markedly lower growth was observed in YSA (LPD=24-270 h, MPD=9 x 10(5) CFU/ml) and spores were inactivated completely within 1-6h in EW. The survivability and inactivation data of B. anthracis in liquid egg products reported in this investigation will be helpful in developing risk assessment models on food biosecurity.

Charge trapping in detector grade thallium bromide and cadmium zinc telluride: Measurement and theory

NASA Astrophysics Data System (ADS)

Elshazly, Ezzat S.; Tepper, Gary; Burger, Arnold

2010-08-01

Carrier trapping times were measured in detector grade thallium bromide (TlBr) and cadmium zinc telluride (CZT) from 300 to 110 K and the experimental data were analyzed using a trapping model. In CZT, because the majority carrier concentration is close to the intrinsic carrier concentration, the trapping time increases exponentially as the temperature decreases below about 160 K. In TlBr, the majority carrier concentration is many orders of magnitude greater than the intrinsic carrier concentration and the trapping time followed a (1/ T) 1/2 temperature dependence over the range of temperatures studied. The results of the model suggest that a moderately deep compensation center could be used to significantly increase the room temperature trapping time in TlBr.

Micro-structure and Air-tightness of Squeeze Casting Motor housing for New Energy Vehicle

NASA Astrophysics Data System (ADS)

Jiang, Y. F.; Kang, Z. Q.; Jiang, W. F.; Wang, K. W.; Sha, D. L.; Li, M. L.; Sun, J.

2018-05-01

In order to improve the performance of automobile parts, the influence of squeeze casting process parameters on casting defects, material structure and air-tightness of aluminum alloy motor housing for new energy vehicle was studied. The results show that the density of the castings increases with the increase in pressure and mold temperature. With increase in pouring temperature, it increases first and then decreases. Pressure has the greatest influence on the density of the castings. Under a certain pressure, with moderate increase in casting temperature and mold temperature, the grain growth begins to increase; the dendrites become less, the new α - Al grains are spherical and granular, the micro-structure is uniform. Also, with increase in pressure, this effect is more pronounced, the air-tightness of castings improve. In conclusion, when the pressure is 110MPa, pouring temperature is 680° C, mold temperature is 280° C, pressure holding for 30s, and punch speed of 0.1m/s, there is no clear shrinkage in the casting, the structure is uniform, the qualified rate of air-tightness of production reaches 86%, and the performance is excellent.

Cryostat system for investigation on new neutron moderator materials at reactor TRIGA PUSPATI

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

Dris, Zakaria bin, E-mail: zakariadris@gmail.com; Centre for Nuclear Energy, Universiti Tenaga Nasional; Mohamed, Abdul Aziz bin

2016-01-22

A simple continuous flow (SCF) cryostat was designed to investigate the neutron moderation of alumina in high temperature co-ceramic (HTCC) and polymeric materials such as Teflon under TRIGA neutron environment using a reflected neutron beam from a monochromator. Cooling of the cryostat will be carried out using liquid nitrogen. The cryostat will be built with an aluminum holder for moderator within stainless steel cylinder pipe. A copper thermocouple will be used as the temperature sensor to monitor the moderator temperature inside the cryostat holder. Initial measurements of neutron spectrum after neutron passing through the moderating materials have been carried outmore » using a neutron spectrometer.« less

Impacts of global warming of 1.5 °C and 2.0 °C on precipitation patterns in China by regional climate model (COSMO-CLM)

NASA Astrophysics Data System (ADS)

Sun, Hemin; Wang, Anqian; Zhai, Jianqing; Huang, Jinlong; Wang, Yanjun; Wen, Shanshan; Zeng, Xiaofan; Su, Buda

2018-05-01

Regional precipitation patterns may change in a warmer climate, thereby increasing flood and drought risks. In this paper, annual, annual maximum, intense, heavy, moderate, light, and trace precipitation are employed as indicators to assess changes in precipitation patterns under two scenarios in which the global mean temperature increases by 1.5 °C and 2.0 °C relative to pre-industrial levels using the regional climate model COSMO-CLM (CCLM). The results show that annual precipitation in China will be approximately 2.5% higher under 1.5 °C warming relative to the present-day baseline (1980-2009), although it will decrease by approximately 4.0% under an additional 0.5 °C increase in global mean temperature. This trend is spatially consistent for regions with annual precipitation of 400-800 mm, which has experienced a drying trend during the past half century; thus, limiting global warming to 1.5 °C may mitigate these drying conditions. The annual maximum precipitation continues to increase from present day levels to the 2.0 °C warming scenario. Relative to the baseline period, the frequency of trace and light precipitation days exhibits a negative trend, while that of moderate, heavy, and intense precipitation days has a positive trend under the 1.5 °C warming scenario. For the 2.0 °C warming world, the frequency of days is projected to decrease for all precipitation categories, although the intensity of intense precipitation increases. Spatially, a decrease in the number of precipitation days is expected to continue in central and northern China, where a drying trend has persisted over the past half century. Southeastern China, which already suffers greatly from flooding, is expected to face more heavy and intense precipitation with an additional 0.5 °C increase in global mean temperature. Meanwhile, the intensity of intense precipitation is expected to increase in northern China, and the contribution of light and moderate precipitation to the annual precipitation is expected to decrease in southeastern China. Therefore, flood risk in northern China and drought risk in southern China should draw more attention for a global air temperature increase from 1.5 °C to 2.0 °C.

Quality and Antioxidant Activity of Buckwheat-Based Cookies Designed for a Raw Food Vegan Diet as Affected by Moderate Drying Temperature.

PubMed

Brožková, Iveta; Dvořáková, Veronika; Michálková, Kateřina; Červenka, Libor; Velichová, Helena

2016-12-01

Buckwheat cookies with various ingredients for raw food vegan diet are usually prepared by soaking them in water at ambient temperature followed by drying at moderate temperature. The aim of this study was to examine the temperature effect on the microbiological quality, antioxidant properties and oxidative stability of lipids of final dried samples. The mixture of ingredients was soaked for 20 h in distilled water, and then cookies were formed and dried in air-forced oven at constant temperature in the range from 40 to 60 °C. Total viable counts, fungi, yeasts, coliform and aerobic spore-forming bacteria counts were evaluated in dried samples and were found to decrease during drying at 50 and 60 °C. Antioxidant activity was determined by DPPH and ABTS assays, and the former showed the highest value at 40 °C. Superoxide dismutase activity was also higher at 40 °C in comparison with that at 60 °C. The percentage of lipid peroxidation inhibition increased with the increase in drying temperature until 4th day of incubation. While peroxide value was significantly higher in samples dried at 40 °C, TBARS values did not show significant changes during the drying process. The results of this study suggest that drying buckwheat-based cookies at 40 °C retained their good antioxidant properties but represent a potentially serious microbial hazard.

A field study of the ventilatory response to ambient temperature and pressure in sport diving.

PubMed Central

Muller, F L

1995-01-01

This study reports on the relationship between minute ventilation (VE) and environmental variables of temperature (T) and pressure (P) during open water diving. The author conducted a total of 38 dives involving either a light (20 dives) or a moderate (18 dives) level of physical activity. Within each of these groups, P and T taken together accounted for about two thirds of the variance in the VE data. A very significant increase in VE was observed as T decreased (1 < T(degrees C) < 22), and the magnitude of this increase at a given pressure level was similar in the 'light' and the 'moderate' data sets. A second order observation, particularly notable at lower temperature, was the decrease in VE with increasing pressure under conditions of light work. Empirical functions of the from VE = A+B/P n[1 + exp(T - 8)/10], where A, B, and n are adjustable variables, could accommodate both data sets over the whole range of T and P. These results are the first obtained under actual diving conditions to provide evidence for interactions between P, T, and VE. Understanding the physiological mechanisms by which these interactions occur would assist in appreciation of the limitations imposed on scuba divers by the environmental conditions as they affect their ventilatory responses. PMID:8800853

Effect of ultrasound on some chemical and microbiological properties of sour cherry juice by response surface methodology.

PubMed

Türken, Tuğba; Erge, Hande S

2017-09-01

In this study, it is aimed to determine effect of ultrasonication on some chemical and microbiological properties of sour cherry juice by response surface methodology, since ultrasound is known as an alternative method for thermal food processing. Sour cherry juice was sonicated at varying amplitude levels (50, 75, 100%); moderate temperatures (20, 30, 40 ℃); and treatment times of 2, 6, 10 min at a constant frequency of 20 kHz. Different ultrasonication amplitudes, temperatures, and times had no significant effect on pH,°Bx, and titratable acidity. A significant increase in total monomeric anthocyanins was observed as the amplitude level and temperature increased (p < 0.01). An increase in the total phenolics was also obtained as the temperature increased (p < 0.05). The effect of amplitude level on antioxidant capacity of sour cherry juice was also found significant (p < 0.05). Color parameters (L*, a*, b*, C, h) generally increased by increasing temperature, amplitude level, and treatment time. It was determined that Escherichia coli O157:H7 significantly affected by temperature and treatment time (p < 0.05).

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.

Reversible Changes in Curie Temperature of Natural Titanomagnetites: Occurrences and Experimental Observations

NASA Astrophysics Data System (ADS)

Jackson, M. J.; Bowles, J. A.

2013-12-01

We have previously reported that natural Al- and Mg- bearing titanomagnetites from historical pyroclastic deposits of Mount St Helens (1980) and of Novarupta (1912) have Curie temperatures Tc that reflect their emplacement temperatures and cooling histories, and moreover that the physical effects can be reproduced experimentally through controlled temperature histories in the laboratory. Curie temperatures increase systematically as a function of time during moderate-temperature (300-425° C) annealing, and then decrease rapidly on exposure to higher temperatures (500-550° C), and we have interpreted this behavior to be the result of temperature-dependent cation redistribution between the tetrahedral and octahedral sites of the inverse spinel structure, with no change in chemical composition or crystal structure. Here we present new results showing similar behavior in a variety of other natural titanomagnetite-bearing extrusive and intrusive rocks, including andesitic and dacitic lithic clasts within the 1993 pyroclastic deposits of Lascar Volcano; a feeder dike from the ~15 Ma Columbia River Basalt Group; and a troctolite from the basal cumulate layered peridotite-troctolite-gabbro sequence of the 1.1 Ga Duluth Complex. For each sample, initial measurement of susceptibility as a function of temperature (k(T) prior to any laboratory annealing) shows a substantial irreversibility, with a Curie temperature during heating that exceeds that during subsequent cooling by a large amount, in some cases approaching 200°, with little or no change in the room-temperature susceptibility. As was the case with the Mt St Helens and Novarupta samples, the diminished Curie temperature at the end of a thermomagnetic experiment can be increased again by heating for hours, days or weeks at moderate temperatures, which we interpret in terms of nonconvergent cation ordering. Tc then decreases again during subsequent k(T) measurements, which we attribute to disordering of the cation distribution at higher temperatures and quenching of the more disordered state during cooling at the relatively rapid rate (~10° C/min) for that experiment.

Temperature and blood flow distribution in the human leg during passive heat stress.

PubMed

Chiesa, Scott T; Trangmar, Steven J; González-Alonso, José

2016-05-01

The influence of temperature on the hemodynamic adjustments to direct passive heat stress within the leg's major arterial and venous vessels and compartments remains unclear. Fifteen healthy young males were tested during exposure to either passive whole body heat stress to levels approaching thermal tolerance [core temperature (Tc) + 2°C; study 1; n = 8] or single leg heat stress (Tc + 0°C; study 2; n = 7). Whole body heat stress increased perfusion and decreased oscillatory shear index in relation to the rise in leg temperature (Tleg) in all three major arteries supplying the leg, plateauing in the common and superficial femoral arteries before reaching severe heat stress levels. Isolated leg heat stress increased arterial blood flows and shear patterns to a level similar to that obtained during moderate core hyperthermia (Tc + 1°C). Despite modest increases in great saphenous venous (GSV) blood flow (0.2 l/min), the deep venous system accounted for the majority of returning flow (common femoral vein 0.7 l/min) during intense to severe levels of heat stress. Rapid cooling of a single leg during severe whole body heat stress resulted in an equivalent blood flow reduction in the major artery supplying the thigh deep tissues only, suggesting central temperature-sensitive mechanisms contribute to skin blood flow alone. These findings further our knowledge of leg hemodynamic responses during direct heat stress and provide evidence of potentially beneficial vascular alterations during isolated limb heat stress that are equivalent to those experienced during exposure to moderate levels of whole body hyperthermia. Copyright © 2016 the American Physiological Society.

Temperature and blood flow distribution in the human leg during passive heat stress

PubMed Central

Chiesa, Scott T.; Trangmar, Steven J.

2016-01-01

The influence of temperature on the hemodynamic adjustments to direct passive heat stress within the leg's major arterial and venous vessels and compartments remains unclear. Fifteen healthy young males were tested during exposure to either passive whole body heat stress to levels approaching thermal tolerance [core temperature (Tc) + 2°C; study 1; n = 8] or single leg heat stress (Tc + 0°C; study 2; n = 7). Whole body heat stress increased perfusion and decreased oscillatory shear index in relation to the rise in leg temperature (Tleg) in all three major arteries supplying the leg, plateauing in the common and superficial femoral arteries before reaching severe heat stress levels. Isolated leg heat stress increased arterial blood flows and shear patterns to a level similar to that obtained during moderate core hyperthermia (Tc + 1°C). Despite modest increases in great saphenous venous (GSV) blood flow (0.2 l/min), the deep venous system accounted for the majority of returning flow (common femoral vein 0.7 l/min) during intense to severe levels of heat stress. Rapid cooling of a single leg during severe whole body heat stress resulted in an equivalent blood flow reduction in the major artery supplying the thigh deep tissues only, suggesting central temperature-sensitive mechanisms contribute to skin blood flow alone. These findings further our knowledge of leg hemodynamic responses during direct heat stress and provide evidence of potentially beneficial vascular alterations during isolated limb heat stress that are equivalent to those experienced during exposure to moderate levels of whole body hyperthermia. PMID:26823344

Influence of extreme low temperature conditions on the dynamic mechanical properties of carbon fiber reinforced polymers

NASA Astrophysics Data System (ADS)

Zaoutsos, S. P.; Zilidou, M. C.

2017-12-01

In the current study dynamic mechanical analysis (DMA) is performed in CFRPs that have been exposed for certain periods of time to extreme low temperatures. Through experimental data arising from respective DMA tests the influence of low temperature exposure (-40 °C) on the dynamic mechanical properties is studied. DMA tests were conducted in CFRP specimens in three point bending mode at both frequency and thermal scans in order to determine the viscoelastic response of the material in low temperatures. All experimental tests were run both for aged and pristine materials for comparison purposes. The results occurred reveal that there is deterioration both on transition temperature (Tg) and storage modulus values while there is also a moderate increase in the damping ability of the tested material as expressed by the factor tanδ as the period of exposure to low temperature increases.

El Niño and its impact on fire weather conditions in Alaska

USGS Publications Warehouse

Hess, Jason C.; Scott, Carven A.; Hufford, Gary L.; Fleming, Michael D.

2001-01-01

Examining the relationship of El Niño to weather patterns in Alaska shows wide climate variances that depend on the teleconnection between the tropics and the northern latitudes. However, the weather patterns exhibited in Alaska during and just after moderate to strong El Niño episodes are generally consistent: above normal temperature and precipitation along the Alaskan coast, and above normal temperature and below normal precipitation in the interior, especially through the winter. The warm, dry conditions in the Alaskan interior increase summer wildfire potential. Statistics on the area burned since 1940 show that 15 out of 17 of the biggest fire years occurred during a moderate to strong El Niño episode. These 15 years account for nearly 63% of the total area burned over the last 58 years. Evidence points to increased dry thunderstorms and associated lightning activity during an El Niño episode; the percentage of total area burned by lightning caused fires during five episodes increased from a normal of less than 40% to a high of about 96%.

Relation of Temperature and Humidity to the Risk of Recurrent Gout Attacks

PubMed Central

Neogi, Tuhina; Chen, Clara; Niu, Jingbo; Chaisson, Christine; Hunter, David J.; Choi, Hyon; Zhang, Yuqing

2014-01-01

Gout attack risk may be affected by weather (e.g., because of volume depletion). We therefore examined the association of temperature and humidity with the risk of recurrent gout attacks by conducting an internet-based case-crossover study in the United States (in 2003–2010) among subjects with a diagnosis of gout who had 1 or more attacks during 1 year of follow-up. We examined the association of temperature and humidity over the prior 48 hours with the risk of gout attacks using a time-stratified approach and conditional logistic regression. Among 632 subjects with gout, there was a significant dose-response relationship between mean temperature in the prior 48 hours and the risk of subsequent gout attack (P = 0.01 for linear trend). Higher temperatures were associated with approximately 40% higher risk of gout attack compared with moderate temperatures. There was a reverse J-shaped relationship between mean relative humidity and the risk of gout attacks (P = 0.03 for quadratic trend). The combination of high temperature and low humidity had the greatest association (odds ratio = 2.04, 95% confidence interval: 1.26, 3.30) compared with moderate temperature and relative humidity. Thus, high ambient temperature and possibly extremes of humidity were associated with an increased risk of gout attack, despite the likelihood that individuals are often in climate-controlled indoor environments. PMID:24993733

Increases in core temperature counterbalance effects of haemoconcentration on blood viscosity during prolonged exercise in the heat.

PubMed

Buono, Michael J; Krippes, Taylor; Kolkhorst, Fred W; Williams, Alexander T; Cabrales, Pedro

2016-02-01

What is the central question of this study? The purpose of the present study was to determine the effects of exercise-induced haemoconcentration and hyperthermia on blood viscosity. What is the main finding and its importance? Exercise-induced haemoconcentration, increased plasma viscosity and increased blood aggregation, all of which increased blood viscosity, were counterbalanced by increased red blood cell (RBC) deformability (e.g. RBC membrane shear elastic modulus and elongation index) caused by the hyperthermia. Thus, blood viscosity remained unchanged following prolonged moderate-intensity exercise in the heat. Previous studies have reported that blood viscosity is significantly increased following exercise. However, these studies measured both pre- and postexercise blood viscosity at 37 °C even though core and blood temperatures would be expected to have increased during the exercise. Consequently, the effect of exercise-induced hyperthermia on mitigating change in blood viscosity may have been missed. The purpose of this study was to isolate the effects of exercise-induced haemoconcentration and hyperthermia and to determine their combined effects on blood viscosity. Nine subjects performed 2 h of moderate-intensity exercise in the heat (37 °C, 40% relative humidity), which resulted in significant increases from pre-exercise values for rectal temperature (from 37.11 ± 0.35 to 38.76 ± 0.13 °C), haemoconcentration (haematocrit increased from 43.6 ± 3.6 to 45.6 ± 3.5%) and dehydration (change in body weight = -3.6 ± 0.7%). Exercise-induced haemoconcentration significantly (P < 0.05) increased blood viscosity by 9% (from 3.97 to 4.33 cP at 300 s(-1)), whereas exercise-induced hyperthermia significantly decreased blood viscosity by 7% (from 3.97 to 3.69 cP at 300 s(-1)). When both factors were considered together, there was no overall change in blood viscosity (from 3.97 to 4.03 cP at 300 s(-1)). The effects of exercise-induced haemoconcentration, increased plasma viscosity and increased red blood cell aggregation, all of which increased blood viscosity, were counterbalanced by increased red blood cell deformability (e.g. red blood cell membrane shear elastic modulus and elongation index) caused by the hyperthermia. Thus, blood viscosity remained unchanged following prolonged moderate-intensity exercise in the heat. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

Low and moderate photosynthetically active radiation affects the flavonol glycosides and hydroxycinnamic acid derivatives in kale (Brassica oleracea var. sabellica) dependent on two low temperatures.

PubMed

Neugart, Susanne; Fiol, Michaela; Schreiner, Monika; Rohn, Sascha; Zrenner, Rita; Kroh, Lothar W; Krumbein, Angelika

2013-11-01

Kale (Brassica oleracea var. sabellica) contains a large number of naturally occurring structurally different non-acylated and acylated flavonol glycosides as well as hydroxycinnamic acid derivatives. The objective of this study was to determine the effect of low and moderate photosynthetic active radiation (PAR) and how these levels interact with low temperature in these phenolic compounds. Juvenile kale plants were treated with PAR levels from 200 to 800 μmol m(-2) s(-1) at 5 and 10 °C under defined conditions in climate chambers. Of the investigated 20 compounds, 11 and 17 compounds were influenced by PAR and temperature, respectively. In addition, an interaction between PAR and temperature was found for eight compounds. The response of the phenolic compounds to PAR was structure-dependent. While quercetin triglycosides increased with higher PAR at 5 and 10 °C, the kaempferol triglycosides exhibited the highest concentrations at 400 μmol m(-2) s(-1). In contrast, kaempferol diglycosides exhibited the highest concentrations at increased PAR levels of 600 and 800 μmol m(-2) s(-1) at 10 °C. However, key genes of flavonol biosynthesis were influenced by temperature but remained unaffected by PAR. Furthermore, there was no interaction between the PAR level and the low temperature in the response of hydroxycinnamic acid derivatives in kale with the exception of caffeoylquinic acid, which decreased with higher PAR levels of 600 and 800 μmol m(-2) s(-1) and at a lower temperature. In conclusion, PAR and its interaction with temperature could be a suitable tool for modifying the profile of phenolic compounds. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Sweating responses during heat acclimation and moderate conditioning

NASA Technical Reports Server (NTRS)

Shvartz, E.; Bhattacharya, A.; Sperinde, S. J.; Brock, P. J.; Sciaraffa, D.; Van Beaumont, W.

1979-01-01

Experiments were conducted on ten young male subjects to determine sweating onset, distribution, and patterns as well as the relationships of these responses to body temperature during heat acclimation and moderate conditioning performed in temperate (24 C) conditions. The subjects are randomly assigned to two groups of five subjects each. The experimental period consisted of eight successive days of either graded exercise to exhaustion on a bicycle ergometer in heat (acclimation group) or in a temperate environment (control group). Major conclusions are that (1) acclimation and conditioning result in relatively more sweat rate on the limbs than on the torso, but that these changes are less related to body temperature than torso sweat rate; and (2) sweating sensitivity increases during acclimation and conditioning, but its contribution to heat acclimation is minor.

Planting Trees in India.

ERIC Educational Resources Information Center

Oswald, James M.

Reforestation is desperately needed in India. Three-fourths of the country's ground surface is experiencing desertification, and primitive forests are being destroyed. Reforestation would help moderate temperatures, increase ground water levels, improve soil fertility, and alleviate a wood shortage. In the past, people from the United States, such…

First experimental evidence for carbon starvation at warm temperatures in epiphytic orchids of tropical cloud forests

NASA Astrophysics Data System (ADS)

Hoch, Guenter; Roemer, Helena; Fioroni, Tiffany; Olmedo, Inayat; Kahmen, Ansgar

2017-04-01

Tropical cloud forests are among the most climate sensitive ecosystems world-wide. The lack of a strong seasonality and the additional dampening of temperature fluctuations by the omnipresence of clouds and fog produce year-round constant climatic conditions. With climate change the presence of clouds and fog is, however, predicted to be reduced. The disappearance of the cooling fog cover will have dramatic consequences for air temperatures, that are predicted to increase locally well over 5 °C by the end of the 21st century. Especially the large number of endemic epiphytic orchids in tropical cloud forests that contribute substantially to the biological diversity of these ecosystems, but are typically adapted to a very narrow climate envelope, are speculated to be very sensitive to the anticipated rise in temperature. In a phytotron experiment we investigated the effect of increasing temperatures on the carbon balance (gas-exchange and the carbon reserve household) of 10 epiphytic orchid species from the genera Dracula, native to tropical, South-American cloud forests. The orchids were exposed to three temperature treatments: i) a constant temperature treatment (23°C/13°C, day/night) simulating natural conditions, ii) a slow temperature ramp of +0.75 K every 10 days, and iii) a fast temperature ramp of +1.5 K every 10 days. CO2 leaf gas-exchanges was determined every 10 days, and concentrations of low molecular weight sugars and starch were analyses from leaf samples throughout the experiment. We found that increasing temperatures had only minor effects on day-time leaf respiration, but led to a moderate increase of respiration during night-time. In contrast to the rather minor effects of higher temperatures on respiration, there was a dramatic decline of net-photosynthesis above day-time temperatures of 29°C, and a complete stop of net-carbon uptake at 33°C in all investigated species. This high sensitivity of photosynthesis to warming was independent of the speed of the temperature increase. Most importantly, the decline of photosynthesis was accompanied by a rapid and complete depletion of leaf starch reserves followed by the prompt death of the plants. We therefore conclude, that temperature increases to 29 - 33°C lead to carbon starvation in epiphytic orchids of tropical cloud forests that is driven by the break-down of photosynthesis. The physiological reason for the observed dysfunction of photosynthesis at only moderately warm temperatures are currently not well understood. Within an ongoing phytotron study, we thus are aiming to confirm and deepen the findings in the genus Dracula in Masdevallia, another orchid genera native and endemic to tropical cloud forests.

Microclimate moderates plant responses to macroclimate warming.

PubMed

De Frenne, Pieter; Rodríguez-Sánchez, Francisco; Coomes, David Anthony; Baeten, Lander; Verstraeten, Gorik; Vellend, Mark; Bernhardt-Römermann, Markus; Brown, Carissa D; Brunet, Jörg; Cornelis, Johnny; Decocq, Guillaume M; Dierschke, Hartmut; Eriksson, Ove; Gilliam, Frank S; Hédl, Radim; Heinken, Thilo; Hermy, Martin; Hommel, Patrick; Jenkins, Michael A; Kelly, Daniel L; Kirby, Keith J; Mitchell, Fraser J G; Naaf, Tobias; Newman, Miles; Peterken, George; Petrík, Petr; Schultz, Jan; Sonnier, Grégory; Van Calster, Hans; Waller, Donald M; Walther, Gian-Reto; White, Peter S; Woods, Kerry D; Wulf, Monika; Graae, Bente Jessen; Verheyen, Kris

2013-11-12

Recent global warming is acting across marine, freshwater, and terrestrial ecosystems to favor species adapted to warmer conditions and/or reduce the abundance of cold-adapted organisms (i.e., "thermophilization" of communities). Lack of community responses to increased temperature, however, has also been reported for several taxa and regions, suggesting that "climatic lags" may be frequent. Here we show that microclimatic effects brought about by forest canopy closure can buffer biotic responses to macroclimate warming, thus explaining an apparent climatic lag. Using data from 1,409 vegetation plots in European and North American temperate forests, each surveyed at least twice over an interval of 12-67 y, we document significant thermophilization of ground-layer plant communities. These changes reflect concurrent declines in species adapted to cooler conditions and increases in species adapted to warmer conditions. However, thermophilization, particularly the increase of warm-adapted species, is attenuated in forests whose canopies have become denser, probably reflecting cooler growing-season ground temperatures via increased shading. As standing stocks of trees have increased in many temperate forests in recent decades, local microclimatic effects may commonly be moderating the impacts of macroclimate warming on forest understories. Conversely, increases in harvesting woody biomass--e.g., for bioenergy--may open forest canopies and accelerate thermophilization of temperate forest biodiversity.

Microclimate moderates plant responses to macroclimate warming

PubMed Central

De Frenne, Pieter; Rodríguez-Sánchez, Francisco; Coomes, David Anthony; Baeten, Lander; Verstraeten, Gorik; Vellend, Mark; Bernhardt-Römermann, Markus; Brown, Carissa D.; Brunet, Jörg; Cornelis, Johnny; Decocq, Guillaume M.; Dierschke, Hartmut; Eriksson, Ove; Gilliam, Frank S.; Hédl, Radim; Heinken, Thilo; Hermy, Martin; Hommel, Patrick; Jenkins, Michael A.; Kelly, Daniel L.; Kirby, Keith J.; Mitchell, Fraser J. G.; Naaf, Tobias; Newman, Miles; Peterken, George; Petřík, Petr; Schultz, Jan; Sonnier, Grégory; Van Calster, Hans; Waller, Donald M.; Walther, Gian-Reto; White, Peter S.; Woods, Kerry D.; Wulf, Monika; Graae, Bente Jessen; Verheyen, Kris

2013-01-01

Recent global warming is acting across marine, freshwater, and terrestrial ecosystems to favor species adapted to warmer conditions and/or reduce the abundance of cold-adapted organisms (i.e., “thermophilization” of communities). Lack of community responses to increased temperature, however, has also been reported for several taxa and regions, suggesting that “climatic lags” may be frequent. Here we show that microclimatic effects brought about by forest canopy closure can buffer biotic responses to macroclimate warming, thus explaining an apparent climatic lag. Using data from 1,409 vegetation plots in European and North American temperate forests, each surveyed at least twice over an interval of 12–67 y, we document significant thermophilization of ground-layer plant communities. These changes reflect concurrent declines in species adapted to cooler conditions and increases in species adapted to warmer conditions. However, thermophilization, particularly the increase of warm-adapted species, is attenuated in forests whose canopies have become denser, probably reflecting cooler growing-season ground temperatures via increased shading. As standing stocks of trees have increased in many temperate forests in recent decades, local microclimatic effects may commonly be moderating the impacts of macroclimate warming on forest understories. Conversely, increases in harvesting woody biomass—e.g., for bioenergy—may open forest canopies and accelerate thermophilization of temperate forest biodiversity. PMID:24167287

INCREASES IN CORE TEMPERATURE COUNTERBALANCE EFFECTS OF HEMOCONCENTRATION ON BLOOD VISCOSITY DURING PROLONGED EXERCISE IN THE HEAT

PubMed Central

Buono, Michael J.; Krippes, Taylor; Kolkhorst, Fred W.; Williams, Alexander T.; Cabrales, Pedro

2015-01-01

Previous studies have reported that blood viscosity is significantly increased following exercise. However, these studies measured both pre- and post-exercise blood viscosity at 37 °C even though core and blood temperatures would be expected to have increased during the exercise. Consequently, the effect of exercise-induced hyperthermia on mitigating change in blood viscosity may have been missed. The purpose of this study was to isolate the effects of exercise-induced hemoconcentration and hyperthermia, as well as determine their combined effects, on blood viscosity. Nine subjects performed 2 h of moderate-intensity exercise in the heat (37 °C, 40% rH), which resulted in significant increases from pre-exercise values for rectal temperature (37.11 ± 0.35 °C to 38.76 ± 0.13 °C), hemoconcentration (hematocrit = 43.6 ± 3.6% to 45.6 ± 3.5%), and dehydration (Δbody weight = −3.6 ± 0.7%). Exercise-induced hemoconcentration significantly (P < 0.05) increased blood viscosity by 9% (3.97 to 4.30 cP at 300 s−1) while exercise-induced hyperthermia significantly decreased blood viscosity by 7% (3.97 to 3.70 cP at 300 s−1). However, when both factors were considered together, there was no overall change in blood viscosity (3.97 to 4.03 cP at 300 s−1). The effects of exercise-induced hemoconcentration, increased plasma viscosity, and increased red blood cell aggregation, all of which increased blood viscosity, were counterbalanced by increased RBC deformability (e.g., RBC membrane shear elastic modulus and elongation index) caused by the hyperthermia. Thus, blood viscosity remained unchanged following prolonged moderate-intensity exercise in the heat. PMID:26682653

Bioconversion of D-glucose into D-glucosone by glucose 2-oxidase from Coriolus versicolor at moderate pressures.

PubMed

Karmali, Amin; Coelho, José

2011-04-01

Glucose 2-oxidase (pyranose oxidase, pyranose:oxygen-2-oxidoreductase, EC 1.1.3.10) from Coriolus versicolor catalyses the oxidation of D-glucose at carbon 2 in the presence of molecular O₂ producing D-glucosone (2-keto-glucose and D-arabino-2-hexosulose) and H₂O₂. It was used to convert D-glucose into D-glucosone at moderate pressures (i.e. up to 150 bar) with compressed air in a modified commercial batch reactor. Several parameters affecting biocatalysis at moderate pressures were investigated as follows: pressure, [enzyme], [glucose], pH, temperature, nature of fluid and the presence of catalase. Glucose 2-oxidase was purified by immobilized metal affinity chromatography on epoxy-activated Sepharose 6B-IDA-Cu(II) column at pH 6.0. The rate of bioconversion of D-glucose increased with the pressure since an increase in the pressure with compressed air resulted in higher rates of conversion. On the other hand, the presence of catalase increased the rate of reaction which strongly suggests that H₂O₂ acted as inhibitor for this reaction. The rate of bioconversion of D-glucose by glucose 2-oxidase in the presence of either nitrogen or supercritical CO₂ at 110 bar was very low compared with the use of compressed air at the same pressure. The optimum temperature (55 °C) and pH (5.0) of D-glucose bioconversion as well as kinetic parameters for this enzyme were determined under moderate pressure. The activation energy (E (a)) was 32.08 kJ mol⁻¹ and kinetic parameters (V(max), K(m), K(cat) and K(cat)/K(m)) for this bioconversion were 8.8 U mg⁻¹ protein, 2.95 mM, 30.81 s⁻¹ and 10,444.06 s⁻¹ M⁻¹, respectively. The biomass of C. versicolor as well as the cell-free extract containing glucose 2-oxidase activity were also useful for bioconversion of D-glucose at moderate pressures. The enzyme was apparently stable at moderate pressures since such pressures did not affect significantly the enzyme activity.

Hall mobility and photoconductivity in TlGaSeS crystals

NASA Astrophysics Data System (ADS)

Qasrawi, A. F.; Gasanly, N. M.

2013-01-01

In this work, the fundamental properties of the TlGaSeS single crystals are investigated by means of temperature dependent electrical resistivity and Hall mobility. The crystal photo-responsibility as function of illumination intensity and temperature is also tested in the temperature range of 350-160 K. The study allowed the determination of acceptor centers as 230 and 450 meV below and above 260 K, and recombination centers as 181, 363, and 10 meV at low, moderate, and high temperatures, respectively. While the temperature-dependent Hall mobility behaved abnormally, the photoconductivity analysis reflected an illumination intensity dependent recombination center. Namely, the recombination center increased from 10 to 90 meV as the light intensity increased from 27.9 to 76.7 mW cm-2, respectively. That strange behavior was attributed to the temporary shift in Fermi level caused by photoexcitation.

Climate change reduces nectar secretion in two common Mediterranean plants.

PubMed

Takkis, Krista; Tscheulin, Thomas; Tsalkatis, Panagiotis; Petanidou, Theodora

2015-09-15

Global warming can lead to considerable impacts on natural plant communities, potentially inducing changes in plant physiology and the quantity and quality of floral rewards, especially nectar. Changes in nectar production can in turn strongly affect plant-pollinator interaction networks-pollinators may potentially benefit under moderate warming conditions, but suffer as resources reduce in availability as elevated temperatures become more extreme. Here, we studied the effect of elevated temperatures on nectar secretion of two Mediterranean Lamiaceae species-Ballota acetabulosa and Teucrium divaricatum. We measured nectar production (viz. volume per flower, sugar concentration per flower and sugar content per flower and per plant), number of open and empty flowers per plant, as well as biomass per flower under a range of temperatures selected ad hoc in a fully controlled climate chamber and under natural conditions outdoors. The average temperature in the climate chamber was increased every 3 days in 3 °C increments from 17.5 to 38.5 °C. Both study species showed a unimodal response of nectar production (volume per flower, sugar content per flower and per plant) to temperature. Optimal temperature for sugar content per flower was 25-26 °C for B. acetabulosa and 29-33 °C for T. divaricatum. According to our results, moderate climate warming predicted for the next few decades could benefit nectar secretion in T. divaricatum as long as the plants are not water stressed, but have a moderate negative effect on B. acetabulosa. Nevertheless, strong warming as predicted by climate change models for the end of the 21st century is expected to reduce nectar secretion in both species and can thus significantly reduce available resources for both wild bees and honeybees in Mediterranean systems. Published by Oxford University Press on behalf of the Annals of Botany Company.

Optimization of NO oxidation by H2O2 thermal decomposition at moderate temperatures.

PubMed

Zhao, Hai-Qian; Wang, Zhong-Hua; Gao, Xing-Cun; Liu, Cheng-Hao; Qi, Han-Bing

2018-01-01

H2O2 was adopted to oxidize NO in simulated flue gas at 100-500°C. The effects of the H2O2 evaporation conditions, gas temperature, initial NO concentration, H2O2 concentration, and H2O2:NO molar ratio on the oxidation efficiency of NO were investigated. The reason for the narrow NO oxidation temperature range near 500°C was determined. The NO oxidation products were analyzed. The removal of NOx using NaOH solution at a moderate oxidation ratio was studied. It was proven that rapid evaporation of the H2O2 solution was critical to increase the NO oxidation efficiency and broaden the oxidation temperature range. the NO oxidation efficiency was above 50% at 300-500°C by contacting the outlet of the syringe needle and the stainless-steel gas pipe together to spread H2O2 solution into a thin film on the surface of the stainless-steel gas pipe, which greatly accelerated the evaporation of H2O2. The NO oxidation efficiency and the NO oxidation rate increased with increasing initial NO concentration. This method was more effective for the oxidation of NO at high concentrations. H2O2 solution with a concentration higher than 15% was more efficient in oxidizing NO. High temperatures decreased the influence of the H2O2 concentration on the NO oxidation efficiency. The oxidation efficiency of NO increased with an increase in the H2O2:NO molar ratio, but the ratio of H2O2 to oxidized NO decreased. Over 80% of the NO oxidation product was NO2, which indicated that the oxidation ratio of NO did not need to be very high. An 86.7% NO removal efficiency was obtained at an oxidation ratio of only 53.8% when combined with alkali absorption.

Optimization of NO oxidation by H2O2 thermal decomposition at moderate temperatures

PubMed Central

Wang, Zhong-hua; Gao, Xing-cun; Liu, Cheng-hao; Qi, Han-bing

2018-01-01

H2O2 was adopted to oxidize NO in simulated flue gas at 100–500°C. The effects of the H2O2 evaporation conditions, gas temperature, initial NO concentration, H2O2 concentration, and H2O2:NO molar ratio on the oxidation efficiency of NO were investigated. The reason for the narrow NO oxidation temperature range near 500°C was determined. The NO oxidation products were analyzed. The removal of NOx using NaOH solution at a moderate oxidation ratio was studied. It was proven that rapid evaporation of the H2O2 solution was critical to increase the NO oxidation efficiency and broaden the oxidation temperature range. the NO oxidation efficiency was above 50% at 300–500°C by contacting the outlet of the syringe needle and the stainless-steel gas pipe together to spread H2O2 solution into a thin film on the surface of the stainless-steel gas pipe, which greatly accelerated the evaporation of H2O2. The NO oxidation efficiency and the NO oxidation rate increased with increasing initial NO concentration. This method was more effective for the oxidation of NO at high concentrations. H2O2 solution with a concentration higher than 15% was more efficient in oxidizing NO. High temperatures decreased the influence of the H2O2 concentration on the NO oxidation efficiency. The oxidation efficiency of NO increased with an increase in the H2O2:NO molar ratio, but the ratio of H2O2 to oxidized NO decreased. Over 80% of the NO oxidation product was NO2, which indicated that the oxidation ratio of NO did not need to be very high. An 86.7% NO removal efficiency was obtained at an oxidation ratio of only 53.8% when combined with alkali absorption. PMID:29668672

Relationship between the Heat Tolerance of Photosynthesis and the Thermal Stability of Rubisco Activase in Plants from Contrasting Thermal Environments1

PubMed Central

Salvucci, Michael E.; Crafts-Brandner, Steven J.

2004-01-01

Inhibition of net photosynthesis (Pn) by moderate heat stress has been attributed to an inability of Rubisco activase to maintain Rubisco in an active form. To examine this proposal, the temperature response of Pn, Rubisco activation, chlorophyll fluorescence, and the activities of Rubisco and Rubisco activase were examined in species from contrasting environments. The temperature optimum of Rubisco activation was 10°C higher in the creosote bush (Larrea tridentata) compared with the Antarctic hairgrass (Deschampsia antarctica), resembling the temperature response of Pn. Pn increased markedly with increasing internal CO2 concentration in Antarctic hairgrass and creosote bush plants subjected to moderate heat stress even under nonphotorespiratory conditions. Nonphotochemical quenching of chlorophyll fluorescence, the effective quantum yield of photochemical energy conversion (ΔF/Fm′) and the maximum yield of PSII (Fv/Fm) were more sensitive to temperature in Antarctic hairgrass and two other species endemic to cold regions (i.e. Lysipomia pumila and spinach [Spinacea oleracea]) compared with creosote bush and three species (i.e. jojoba [Simmondsia chinensis], tobacco [Nicotiana tabacum], and cotton [Gossypium hirsutum]) from warm regions. The temperature response of activity and the rate of catalytic inactivation of Rubisco from creosote bush and Antarctic hairgrass were similar, whereas the optimum for ATP hydrolysis and Rubisco activation by recombinant creosote bush, cotton, and tobacco activase was 8°C to 10°C higher than for Antarctic hairgrass and spinach activase. These results support a role for activase in limiting photosynthesis at high temperature. PMID:15084731

Heat, Heat Waves, and Hospital Admissions among the Elderly in the United States, 1992–2006

PubMed Central

Zanobetti, Antonella; Schwartz, Joel D.; Wellenius, Gregory A.; O’Neill, Marie S.

2014-01-01

Background: Heat-wave frequency, intensity, and duration are increasing with global climate change. The association between heat and mortality in the elderly is well documented, but less is known regarding associations with hospital admissions. Objectives: Our goal was to determine associations between moderate and extreme heat, heat waves, and hospital admissions for nonaccidental causes among Medicare beneficiaries ≥ 65 years of age in 114 cities across five U.S. climate zones. Methods: We used Medicare inpatient billing records and city-specific data on temperature, humidity, and ozone from 1992 through 2006 in a time-stratified case-crossover design to estimate the association between hospitalization and moderate [90th percentile of apparent temperature (AT)] and extreme (99th percentile of AT) heat and heat waves (AT above the 95th percentile over 2–8 days). In sensitivity analyses, we additionally considered confounding by ozone and holidays, different temperature metrics, and alternate models of the exposure–response relationship. Results: Associations between moderate heat and hospital admissions were minimal, but extreme heat was associated with a 3% (95% CI: 2%, 4%) increase in all-cause hospital admissions over the subsequent 8 days. In cause-specific analyses, extreme heat was associated with increased hospitalizations for renal (15%; 95% CI: 9%, 21%) and respiratory (4%; 95% CI: 2%, 7%) diseases, but not for cardiovascular diseases. An added heat-wave effect was observed for renal and respiratory admissions. Conclusion: Extreme heat is associated with increased hospital admissions, particularly for renal causes, among the elderly in the United States. Citation: Gronlund CJ, Zanobetti A, Schwartz JD, Wellenius GA, O’Neill MS. 2014. Heat, heat waves, and hospital admissions among the elderly in the United States, 1992–2006. Environ Health Perspect 122:1187–1192; http://dx.doi.org/10.1289/ehp.1206132 PMID:24905551

Effect of heat stress on body temperature in healthy early postpartum dairy cows.

PubMed

Burfeind, O; Suthar, V S; Heuwieser, W

2012-12-01

Measurement of body temperature is the most common method for an early diagnosis of sick cows in fresh cow protocols currently used on dairy farms. Thresholds for fever range from 39.4 °C to 39.7 °C. Several studies attempted to describe normal temperature ranges for healthy dairy cows in the early puerperium. However, the definition of a healthy cow is variable within these studies. It is challenging to determine normal temperature ranges for healthy cows because body temperature is usually included in the definition. Therefore, the objectives of this study were to identify factors that influence body temperature in healthy dairy cows early postpartum and to determine normal temperature ranges for healthy cows that calved in a moderate (temperature humidity index: 59.8 ± 3.8) and a hot period (temperature humidity index: 74.1 ± 4.4), respectively, excluding body temperature from the definition of the health status. Furthermore, the prevalence of fever was calculated for both periods separately. A subset of 17 (moderate period) and 15 cows (hot period) were used for analysis. To ensure their uterine health only cows with a serum haptoglobin concentration ≤ 1.1 g/L were included in the analysis. Therefore, body temperature could be excluded from the definition. A vaginal temperature logger that measured vaginal temperature every 10 min was inserted from Day 2 to 10 after parturition. Additionally rectal temperature was measured twice daily. Day in milk (2 to 10), period (moderate and hot), and time of day had an effect on rectal and vaginal temperature. The prevalence of fever (≥ 39.5 °C) was 7.4% and 28.1% for rectal temperature in the moderate and hot period, respectively. For vaginal temperature (07.00 to 11.00 h) it was 10% and 33%, respectively, considering the same threshold and period. This study demonstrates that body temperature in the early puerperium is influenced by several factors (day in milk, climate, time of day). Therefore, these factors have to be considered when interpreting body temperature measures to identify sick cows. Furthermore, the prevalence of fever considering different thresholds is higher during hot than moderate periods. However, even in a moderate period healthy cows can exhibit a body temperature that is considered as fever. This fact clearly illustrates that fever alone should not be considered the decision criterion whether a cow is allocated to an antibiotic treatment, although it is the most important one that is objectively measurable. Copyright © 2012 Elsevier Inc. All rights reserved.

Localization and superconductivity in (BEDT-TIF) 2Cu[N(CN) 2]Cl: Pressure effect

NASA Astrophysics Data System (ADS)

Sushko, Yu. V.; Bondarenko, V. A.; Petrosov, R. A.; Kushch, N. D.; Yagubskii, E. B.

1991-12-01

At ambient pressure titled salt exhibits the insulating ground state. Superconductivity with T c near 12 K appears at the pressure of 95 bar and under the moderate pressures coexists with the high-temperature semiconducting regime. At 340 bar the metallic behavior of resistance is stabilized in whole temperature range and T c reaches the maximum value (midpoint 12.8 K, onset 13.8 K). Further pressure increasing causes rapid T c decreasing.

Extraction of valerenic acids from valerian (Valeriana officinalis L.) rhizomes.

PubMed

Boyadzhiev, L; Kancheva, D; Gourdon, C; Metcheva, D

2004-09-01

Extraction of valerenic acids (valerenic, acetoxyvalerenic and hydroxyvalerenic) from dry ground rhizomes of valerian (Valeriana officinalis L.) was studied. The effect of ethanol concentration in the solvent, extraction temperature and drug particle size on extraction kinetics were investigated and the optimum values of these process parameters were determined for the case of intensively stirred two-phase dispersion. It was found that increased processing temperature favors extraction kinetics, but provokes moderate degradation of valerenic acids.

Contrasting Response of Carbon Fluxes to Winter Warming across Land Cover Types in Southern NH, USA

NASA Astrophysics Data System (ADS)

Sanders-DeMott, R.; Ouimette, A.; Lepine, L. C.; Fogarty, S.; Burakowski, E. A.; Contosta, A.; Ollinger, S. V.; Conte, T.

2017-12-01

Natural and managed ecosystems play a key role in climate through regulation of carbon dioxide, as well as their effects on other greenhouse gases, surface heat fluxes, and albedo. In the northeastern United States, winter air temperatures are rising more rapidly than mean annual temperatures and the depth and duration of seasonal snowpack is decreasing. Although winter fluxes of carbon are small relative to the growing season, there is mounting evidence that biological processes in winter contribute significantly to annual ecosystem carbon budgets and that changes in winter conditions could lead to shifting patterns and magnitudes of seasonal carbon uptake. To determine the response of differing land cover types to variation in winter conditions we used eddy covariance to monitor carbon exchange from a co-located mixed temperate forest and a managed grassland in Durham, NH from 2014-2017, which included an anomalous warm winter (air temperatures 3°C warmer than 14-year mean) with low snowpack in 2016. We examined cumulative winter and spring net ecosystem exchange, as well as the sensitivity of ecosystem respiration to air and soil temperatures in the presence and absence of a deep (>15 cm) snowpack. We found that warm winter temperatures and low snow conditions led to relatively large cumulative losses of carbon from the forest in February/March 2016, while the grassland was a moderate net sink for carbon during the same period. When temperatures were above 0°C, mid-day carbon uptake in the grassland was controlled by the presence or absence of snow cover. Our results suggest that forest carbon losses to the atmosphere in deciduous forests may increase during warm, snow-free winter conditions when vegetation is restricted in winter carbon uptake capacity by phenology. However, non-forested vegetation such as perennial grasses have a greater potential to activate photosynthesis in winter and to take up carbon in the "dormant season," perhaps moderating increasing winter carbon losses due to increasing winter temperatures.

Temperature and pressure dependences of kimberlite melts viscosity (experimental-theoretical study)

NASA Astrophysics Data System (ADS)

Persikov, Eduard; Bykhtiyarov, Pavel; Cokol, Alexsander

2016-04-01

Experimental data on temperature and pressure dependences of viscosity of model kimberlite melts (silicate 82 + carbonate 18, wt. %, 100NBO/T = 313) have been obtained for the first time at 100 MPa of CO2 pressure and at the lithostatic pressures up to 7.5 GPa in the temperature range 1350 oC - 1950 oC using radiation high gas pressure apparatus and press free split-sphere multi - anvil apparatus (BARS). Experimental data obtained on temperature and pressure dependences of viscosity of model kimberlite melts at moderate and high pressures is compared with predicted data on these dependences of viscosity of basaltic melts (100NBO/T = 58) in the same T, P - range. Dependences of the viscosity of model kimberlite and basaltic melts on temperature are consistent to the exponential Arrenian equation in the T, P - range of experimental study. The correct values of activation energies of viscous flow of kimberlite melts have been obtained for the first time. The activation energies of viscous flow of model kimberlite melts exponentially increase with increasing pressure and are equal: E = 130 ± 1.3 kJ/mole at moderate pressure (P = 100 MPa) and E = 160 ± 1.6 kJ/mole at high pressure (P = 5.5 GPa). It has been established too that the viscosity of model kimberlite melts exponentially increases on about half order of magnitude with increasing pressures from 100 MPa to 7.5 GPa at the isothermal condition (1800 oC). It has been established that viscosity of model kimberlite melts at the moderate pressure (100 MPa) is lover on about one order of magnitude to compare with the viscosity of basaltic melts, but at high pressure range (5.5 - 7.5 GPa), on the contrary, is higher on about half order of magnitude at the same values of the temperatures. Here we use both a new experimental data on viscosity of kimberlite melts and our structural chemical model for calculation and prediction the viscosity of magmatic melts [1] to determine the fundamental features of viscosity of kimberlite and basaltic magmas at the T, P - parameters of the Earth's crust and upper mantle. The Russian Foundation for Basic Research (project 15-05-01318) and the Russian Science Foundation (project 14-27-00054) are acknowledged for the financial support. [1] Persikov, E.S. & Bukhtiyarov, P.G. (2009) Russian Geology & Geophysics, 50, No 12, 1079-1090.

Specific amino acids responsible for the cold adaptedness of Micrococcus antarcticus β-glucosidase BglU.

PubMed

Miao, Li-Li; Fan, Hong-Xia; Qu, Jie; Liu, Ying; Liu, Zhi-Pei

2017-03-01

Psychrophilic enzymes display efficient activity at moderate or low temperatures (4-25 °C) and are therefore of great interest in biotechnological industries. We previously examined the crystal structure of BglU, a psychrophilic β-glucosidase from the bacterium Micrococcus antarcticus, at 2.2 Å resolution. In structural comparison and sequence alignment with mesophilic (BglB) and thermophilic (GlyTn) counterpart enzymes, BglU showed much lower contents of Pro residue and of charged amino acids (particularly positively charged) on the accessible surface area. In the present study, we investigated the roles of specific amino acid residues in the cold adaptedness of BglU. Mutagenesis assays showed that the mutations G261R and Q448P increased optimal temperature (from 25 to 40-45 °C) at the expense of low-temperature activity, but had no notable effects on maximal activity or heat lability. Mutations A368P, T383P, and A389E significantly increased optimal temperature (from 25 to 35-40 °C) and maximal activity (~1.5-fold relative to BglU). Thermostability of A368P and A389E increased slightly at 30 °C. Mutations K163P, N228P, and H301A greatly reduced enzymatic activity-almost completely in the case of H301A. Low contents of Pro, Arg, and Glu are important factors contributing to BglU's psychrophilic properties. Our findings will be useful in structure-based engineering of psychrophilic enzymes and in production of mutants suitable for a variety of industrial processes (e.g., food production, sewage treatment) at cold or moderate temperatures.

Northern Hemisphere extratropical winter cyclones variability over the 20th century derived from ERA-20C reanalysis

NASA Astrophysics Data System (ADS)

Varino, Filipa; Arbogast, Philippe; Joly, Bruno; Riviere, Gwendal; Fandeur, Marie-Laure; Bovy, Henry; Granier, Jean-Baptiste

2018-03-01

The multi-decadal variations of wintertime extra-tropical cyclones during the last century are studied using a vorticity-based tracking algorithm applied to the long-term ERA-20C reanalysis from ECMWF. The variability of moderate-to-deep extra-tropical winter cyclones in ERA-20C show three distinct periods. Two at the beginning and at the end of the century (1900-1935 and 1980-2010) present weak or no significant trends in the Northern Hemisphere as a whole and only some regional trends. The period in between (1935-1980) is marked by a significant increase in Northern Hemisphere moderate-to-deep cyclones frequency. During the latter period, polar regions underwent a significant cooling over the whole troposphere that increased and shifted poleward the mid-latitude meridional temperature gradient and the baroclinicity. This is linked to positive-to-negative shifts of the PDO between 1935 and 1957 and of the AMO between 1957 and 1980 which mainly reinforced the storm-track eddy generation in the North Pacific and North Atlantic regions respectively, as seen from baroclinic conversion from mean to eddy potential energy. As a result, both the North Pacific and North Atlantic extra-tropical storms increase in frequency during the two subperiods (1935-1957 and 1957-1980), together with other storm-track quantities such as the high-frequency eddy kinetic energy. In contrast, the first and third periods are characterized by a warming of the polar temperatures. However, as the stronger warming is confined to the lower troposphere, the baroclinicity do not uniformly increase in the whole troposphere. This may explain why the recent rapid increase in polar temperatures has not affected the behaviour of extratropical cyclones very much. Finally, the large magnitude of the positive trend found in moderate-to-deep cyclone frequency during the second period is still questioned as the period is marked by an important increase in the number of assimilated observations. However, the dynamical link between changes in cyclone frequency, changes in large-scale baroclinicity and ocean decadal variability found in the present study makes us confident on the sign of the detected cyclone trend.

Increasing chilling reduces heat requirement for floral budbreak in peach

USDA-ARS?s Scientific Manuscript database

Response to chilling temperatures is a critical factor in the suitability of peach [Prunus persica (L.) Batsch] cultivars to moderate climates such as in the southeastern United States. Time of bloom depends on the innate chilling requirement of the cultivar as well as the timing and quantity of co...

The effect of total carbon on microscopic soil properties and implications for crop production

USDA-ARS?s Scientific Manuscript database

Soil structure is a dynamic property affected by physical, chemical, and microbiological processes. Addition of organic matter to soils and the use of different management practices have been reported to impact soil structure and crop production. Moderation in soil temperature and increases in mic...

Temperature-dependent residual shear strength characteristics of smectite-bearing landslide soils

NASA Astrophysics Data System (ADS)

Shibasaki, Tatsuya; Matsuura, Sumio; Hasegawa, Yoichi

2017-02-01

This paper presents experimental investigations regarding the effect of temperature on the residual strength of landslide soils at slow-to-moderate shearing velocities. We performed ring-shear tests on 23 soil samples at temperatures of 6-29°C. The test results show that the shear strength of smectite-rich soils decreased when temperatures were relatively low. These positive temperature effects (strength losses at lower temperatures) observed for smectite-bearing soils are typical under relatively slow shearing rates. In contrast, under relatively high shearing rates, strength was gained as temperature decreased. As rheological properties of smectite suspensions are sensitive to environmental factors, such as temperature, pH, and dissolved ions, we inferred that temperature-dependent residual strengths of smectitic soils are also attributed to their specific rheological properties. Visual and scanning electron microscope observations of Ca-bentonite suggest that slickensided shear surfaces at slow shearing rates are very shiny and smooth, whereas those at moderate shearing rates are not glossy and are slightly turbulent, indicating that platy smectite particles are strongly orientated at slow velocities. The positive temperature effect is probably due to temperature-dependent microfriction that is mobilized in the parallel directions of the sheet structure of hydrous smectite particles. On the contrary, the influence of microviscous resistance, which appears in the vertical directions of the lamination, is assumed to increase at faster velocities. Our results imply that if slip-surface soils contain high fractions of smectite, decreases in ground temperature can lead to lowered shear resistance of the slip surface and trigger slow landslide movement.

Prompt increase of ultrashort laser pulse transmission through thin silver films

NASA Astrophysics Data System (ADS)

Bezhanov, S. G.; Danilov, P. A.; Klekovkin, A. V.; Kudryashov, S. I.; Rudenko, A. A.; Uryupin, S. A.

2018-03-01

We study experimentally and numerically the increase in ultrashort laser pulse transmissivity through thin silver films caused by the heating of electrons. Low to moderate energy femtosecond laser pulse transmission measurements through 40-125 nm thickness silver films were carried out. We compare the experimental data with the values of transmitted fraction of energy obtained by solving the equations for the field together with the two-temperature model. The measured values were fitted with sufficient accuracy by varying the electron-electron collision frequency whose exact values are usually poorly known. Since transmissivity experiences more pronounced changes with the increase in temperature compared to reflectivity, we suggest this technique for studying the properties of nonequilibrium metals.

Randomized controlled trial of moderate hypothermia versus deep hypothermia anesthesia on brain injury during Stanford A aortic dissection surgery.

PubMed

Sun, Xufang; Yang, Hua; Li, Xinyu; Wang, Yue; Zhang, Chuncheng; Song, Zhimin; Pan, Zhenxiang

2018-01-01

This study aimed to compare the effects of moderate versus deep hypothermia anesthesia for Stanford A aortic dissection surgery on brain injury. A total of 82 patients who would undergo Stanford A aortic dissection surgery were randomized into two groups: moderate hypothermia group (MH, n = 40, nasopharyngeal temperature 25 °C, and rectal temperature 28 °C) and deep hypothermia group (DH, n = 42, nasopharyngeal temperature 20 °C, and rectal temperature 25 °C). Different vascular replacement techniques including aortic root replacement, Bentall, and Wheat were used. The intraoperative and postoperative indicators of these patients were recorded. There were no differences in intraoperative and postoperative measures between MH and DH groups. The concentrations of neuron-specific enolase and S-100β increased with operation time, and were significantly lower in MH group than those in the DH group (P < 0.05). The occurrence rates of complications including chenosis, postoperative agitation, and neurological complications in MH group were significantly lower than in DH group. The recovery time, postoperative tube, and ICU intubation stay were significantly shorter in MH group than those in DH group (P < 0.05). There were no significant differences revealed in hospital stay and death rate. MH exhibited better cerebral protective effects, less complications, and shorter tube time than DH in surgery for Stanford A aortic dissection.

Hydrolysis of Glycosidic Flavonoids during the Preparation of Danggui Buxue Tang: An Outcome of Moderate Boiling of Chinese Herbal Mixture

PubMed Central

Zhang, Wendy Li; Chen, Jian-Ping; Lam, Kelly Yin-Ching; Zhan, Janis Ya-Xian; Yao, Ping; Dong, Tina Ting-Xia; Tsim, Karl Wah-Keung

2014-01-01

Chemical change during boiling of herbal mixture is a puzzle. By using Danggui Buxue Tang (DBT), a herbal decoction that contains Astragali Radix (AR) and Angelicae Sinensis Radix (ASR), we developed a model in analyzing the hydrolysis of flavonoid glycosides during the boiling of herbal mixture in water. A proper preparation of DBT is of great benefit to the complete extraction of bioactive ingredients. Boiling of DBT in water increased the solubility of AR-derived astragaloside IV, calycosin, formononetin, calycosin-7-O-β-D-glucoside, and ononin in a time- and temperature-dependent manner: the amounts of these chemicals reached a peak at 2 h. The glycosidic resides of AR, calycosin-7-O-β-D-glucoside, and ononin could be hydrolyzed during the moderate boiling process to form calycosin and formononetin, respectively. The hydrolysis efficiency was strongly affected by pH, temperature, and amount of herbs. Interestingly, the preheated herbs were not able to show this hydrolytic activity. The current results supported the rationality of ancient preparation of DBT in boiling water by moderate heat. PMID:24744813

Neurocognitive and Somatic Components of Temperature Increases during g-Tummo Meditation: Legend and Reality

PubMed Central

Kozhevnikov, Maria; Elliott, James; Shephard, Jennifer; Gramann, Klaus

2013-01-01

Stories of g-tummo meditators mysteriously able to dry wet sheets wrapped around their naked bodies during a frigid Himalayan ceremony have intrigued scholars and laypersons alike for a century. Study 1 was conducted in remote monasteries of eastern Tibet with expert meditators performing g-tummo practices while their axillary temperature and electroencephalographic (EEG) activity were measured. Study 2 was conducted with Western participants (a non-meditator control group) instructed to use the somatic component of the g-tummo practice (vase breathing) without utilization of meditative visualization. Reliable increases in axillary temperature from normal to slight or moderate fever zone (up to 38.3°C) were observed among meditators only during the Forceful Breath type of g-tummo meditation accompanied by increases in alpha, beta, and gamma power. The magnitude of the temperature increases significantly correlated with the increases in alpha power during Forceful Breath meditation. The findings indicate that there are two factors affecting temperature increase. The first is the somatic component which causes thermogenesis, while the second is the neurocognitive component (meditative visualization) that aids in sustaining temperature increases for longer periods. Without meditative visualization, both meditators and non-meditators were capable of using the Forceful Breath vase breathing only for a limited time, resulting in limited temperature increases in the range of normal body temperature. Overall, the results suggest that specific aspects of the g-tummo technique might help non-meditators learn how to regulate their body temperature, which has implications for improving health and regulating cognitive performance. PMID:23555572

Characterization of photosynthetic ferredoxin from the Antarctic alga Chlamydomonas sp. UWO241 reveals novel features of cold adaptation.

PubMed

Cvetkovska, Marina; Szyszka-Mroz, Beth; Possmayer, Marc; Pittock, Paula; Lajoie, Gilles; Smith, David R; Hüner, Norman P A

2018-05-08

The objective of this work was to characterize photosynthetic ferredoxin from the Antarctic green alga Chlamydomonas sp. UWO241, a key enzyme involved in distributing photosynthetic reducing power. We hypothesize that ferredoxin possesses characteristics typical of cold-adapted enzymes, namely increased structural flexibility and high activity at low temperatures, accompanied by low stability at moderate temperatures. To address this objective, we purified ferredoxin from UWO241 and characterized the temperature dependence of its enzymatic activity and protein conformation. The UWO241 ferredoxin protein, RNA, and DNA sequences were compared with homologous sequences from related organisms. We provide evidence for the duplication of the main ferredoxin gene in the UWO241 nuclear genome and the presence of two highly similar proteins. Ferredoxin from UWO241 has both high activity at low temperatures and high stability at moderate temperatures, representing a novel class of cold-adapted enzymes. Our study reveals novel insights into how photosynthesis functions in the cold. The presence of two distinct ferredoxin proteins in UWO241 could provide an adaptive advantage for survival at cold temperatures. The primary amino acid sequence of ferredoxin is highly conserved among photosynthetic species, and we suggest that subtle differences in sequence can lead to significant changes in activity at low temperatures. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Molecular-scale hydrophobic interactions between hard-sphere reference solutes are attractive and endothermic.

PubMed

Chaudhari, Mangesh I; Holleran, Sinead A; Ashbaugh, Henry S; Pratt, Lawrence R

2013-12-17

The osmotic second virial coefficients, B2, for atomic-sized hard spheres in water are attractive (B2 < 0) and become more attractive with increasing temperature (ΔB2/ΔT < 0) in the temperature range 300 K ≤ T ≤ 360 K. Thus, these hydrophobic interactions are attractive and endothermic at moderate temperatures. Hydrophobic interactions between atomic-sized hard spheres in water are more attractive than predicted by the available statistical mechanical theory. These results constitute an initial step toward detailed molecular theory of additional intermolecular interaction features, specifically, attractive interactions associated with hydrophobic solutes.

Live performance of male broilers subjected to constant or increasing air velocities at moderate temperatures with a high dew point.

PubMed

Dozier, W A; Lott, B D; Branton, S L

2005-08-01

This study examined the effects of varying air velocities vs. a constant air velocity with a cyclic temperature curve of 25-30-25 degrees C and a dew point of 23 degrees C on broilers from 28 to 49 d of age. Four replicate trials were conducted. In each trial, 742 male broilers were randomly allocated to 6 floor pens or 2 air velocity tunnels, with each tunnel consisting of 4 pens. Bird density, feeder, and waterer space were similar across all pens (53 birds/ pen; 0.07 m2/bird). The treatments were control (still air), constant air velocity of 120 m/min, and increasing air velocity (90 m/min from 28 to 35 d, 120 m/min from 36 to 42 d, and 180 m/min from 43 to 49 d). Birds grown in a still air environment gained less weight, consumed less feed, and converted feed less efficiently between 28 and 49 d than birds subjected to moving air (constant or increasing). Growth responses between the air velocity treatments were similar from 28 to 35 and 36 to 42 d of age. Increasing air velocity to 180 m/min improved (P < or = 0.02) the growth rate of broilers from 43 to 49 d of age over birds receiving an air velocity of 120 m/min, but the incidence of mortality was not affected. These results provide evidence that increasing air velocity from 120 to 180 m/min is beneficial to broilers weighing 2.5 kg or greater when exposed to moderate temperatures.

Standardized performance tests of collectors of solar thermal energy: Prototype moderately concentrating grooved collectors

NASA Technical Reports Server (NTRS)

1976-01-01

Prototypes of moderately concentrating grooved collectors were tested with a solar simulator for varying inlet temperature, flux level, and incident angle. Collector performance is correlated in terms of inlet temperature and flux level.

Temperature and hydrology affect methane emissions from Prairie Pothole Wetlands

USGS Publications Warehouse

Bansal, Sheel; Tangen, Brian; Finocchiaro, Raymond

2016-01-01

The Prairie Pothole Region (PPR) in central North America consists of millions of depressional wetlands that each have considerable potential to emit methane (CH4). Changes in temperature and hydrology in the PPR from climate change may affect methane fluxes from these wetlands. To assess the potential effects of changes in climate on methane emissions, we examined the relationships between flux rates and temperature or water depth using six years of bi-weekly flux measurements during the snow-free period from six temporarily ponded and six permanently ponded wetlands in North Dakota, USA. Methane flux rates were among the highest reported for freshwater wetlands, and had considerable spatial and temporal variation. Methane flux rates increased with increasing temperature and water depth, and were especially high when conditions were warmer and wetter than average (163 ± 28 mg CH4 m−2 h−1) compared to warmer and drier (37 ± 7 mg CH4 m−2 h−1). Methane emission rates from permanent wetlands were less sensitive to changes in temperature and water depth compared to temporary wetlands, likely due to higher sulfate concentrations in permanent wetlands. While the predicted increase in temperature with climate change will likely increase methane emission rates from PPR wetlands, drier conditions could moderate these increases.

Impact of new land boundary conditions from Moderate Resolution Imaging Spectroradiometer (MODIS) data on the climatology of land surface variables

NASA Astrophysics Data System (ADS)

Tian, Y.; Dickinson, R. E.; Zhou, L.; Shaikh, M.

2004-10-01

This paper uses the Community Land Model (CLM2) to investigate the improvements of a new land surface data set, created from multiple high-quality collection 4 Moderate Resolution Imaging Spectroradiometer data of leaf area index (LAI), plant functional type, and vegetation continuous fields, for modeled land surface variables. The previous land surface data in CLM2 underestimate LAI and overestimate the percent cover of grass/crop over most of the global area. For snow-covered regions with abundant solar energy the increased LAI and percent cover of tree/shrub in the new data set decreases the percent cover of surface snow and increases net radiation and thus increases ground and surface (2-m) air temperature, which reduces most of the model cold bias. For snow-free regions the increased LAI and changes in the percent cover from grass/crop to tree or shrub decrease ground and surface air temperature by converting most of the increased net radiation to latent heat flux, which decreases the model warm bias. Furthermore, the new data set greatly decreases ground evaporation and increases canopy evapotranspiration over tropical forests, especially during the wet season, owing to the higher LAI and more trees in the new data set. It makes the simulated ground evaporation and canopy evapotranspiration closer to reality and also reduces the warm biases over tropical regions.

Response surface method optimization of ectoine fermentation medium with moderate halophilic bacteria Halomonas sp. H02

NASA Astrophysics Data System (ADS)

Li, T. T.; Qu, A.; Yuan, X. N.; Tan, F. X.; Li, X. W.; Wang, T.; Zhang, L. H.

2017-07-01

Moderate halophilic bacteria are of halophilic bacteria whose suitable growth of NaCl is 5-10%. When the moderate halophilic bacteria response to high osmotic stress, the intracellular will synthesize small organic molecule compatible solutes. Ectoine, which is the major synthetic osmotic compatible solutes for moderate halophilic bacteria, can help microbial enzymes, nucleic acids and the whole cell resist to hypertonic, high temperature, freezing and other inverse environment. In order to increase the Ectoine production of Moderate halophilic bacteria Halomonas sp. H02, the Ectoine fermentation medium component was optimized by Plackett-Burman (PB) and Response Surface Methodology (RSM) based on the principle of non-complete equilibrium The results of PB experiments showed that the three main influencing factors of Moderate halophilic bacteria Halomonas sp. H02 synthesis Ectoine culture medium were C5H8NNaO4 concentration, NaCl concentration and initial pH. According to the center point of the steepest climbing experiment, the central combination design experiment was used to show that the model is consistent with the actual situation. The optimum combination of three influencing factors were C5H8NNaO4 41 g/L, NaCl 87.2 g/L and initial pH 5.9, and the predicted amount of Ectoine was 1835.8 mg/L, increased by 41.6%.

Thermopreference, tolerance and metabolic rate of early stages juvenile Octopus maya acclimated to different temperatures.

PubMed

Noyola, Javier; Caamal-Monsreal, Claudia; Díaz, Fernando; Re, Denisse; Sánchez, Adolfo; Rosas, Carlos

2013-01-01

Thermopreference, tolerance and oxygen consumption rates of early juveniles Octopus maya (O. maya; weight range 0.38-0.78g) were determined after acclimating the octopuses to temperatures (18, 22, 26, and 30°C) for 20 days. The results indicated a direct relationship between preferred temperature (PT) and acclimated temperature, the PT was 23.4°C. Critical Thermal Maxima, (CTMax; 31.8±1.2, 32.7±0.9, 34.8±1.4 and 36.5±1.0) and Critical Thermal Minima, (CTMin; 11.6±0.2, 12.8±0.6, 13.7±1.0, 19.00±0.9) increased significantly (P<0.05) with increasing acclimation temperatures. The endpoint for CTMax was ink release and for CTMin was tentacles curled, respectively. A thermal tolerance polygon over the range of 18-30°C resulted in a calculated area of 210.0°C(2). The oxygen consumption rate increased significantly α=0.05 with increasing acclimation temperatures between 18 and 30°C. Maximum and minimum temperature quotients (Q10) were observed between 26-30°C and 22-26°C as 3.03 and 1.71, respectively. These results suggest that O. maya has an increased capability for adapting to moderate temperatures, and suggest increased culture potential in subtropical regions southeast of México. Copyright © 2012 Elsevier Ltd. All rights reserved.

Demonstration of Combined Zero-Valent Iron and Electrical Resistance Heating for In Situ Trichloroethene Remediation

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

Truex, Michael J.; Macbeth, Tamzen; Vermeul, Vincent R.

The effectiveness of in situ treatment using zero-valent iron to remediate sites with non-aqueous phase or significant sediment-associated contaminant mass can be limited by relatively low rates of mass transfer to bring contaminants in contact with the reactive media. For a field test in a trichloroethene source area, combining moderate-temperature (maximum 50oC) subsurface electrical resistance heating with in situ ZVI treatment was shown to accelerate dechlorination and dissolution rates by a factor of 4 to 6 based on organic daughter products and a factor 8-16 using a chloride concentrations. A mass-discharge-based analysis was used to evaluate reaction, dissolution, and volatilizationmore » at ambient groundwater temperature (~10oC) and as temperature was increased up to about 50oC. Increased reaction and contaminant dissolution were observed with increased temperature, but volatilization was minimal during the test because in situ reactions maintained low aqueous-phase TCE concentrations.« less

Fluid-electrolyte shifts and thermoregulation - Rest and work in heat with head cooling

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Van Beaumont, W.; Brock, P. J.; Montgomery, L. D.; Morse, J. T.; Shvartz, E.; Kravik, S.

1980-01-01

The effects of head cooling on thermoregulation and associated plasma fluid and electrolyte shifts during rest and submaximal exercise in the heat are investigated. Thermoregulatory responses and plasma volume were measured in four male subjects fitted with liquid-cooled neoprene headgear during 60 min of rest, 60 min of ergometer exercise at 45% maximal oxygen uptake and 30 min of recovery in the supine position at 40.1 C and 40% relative humidity. It is found that, compared to control responses, head cooling decreased thigh sweating and increased mean skin temperature at rest and attenuated increases in thigh sweating, heart rate, rectal temperature and ventilation during exercise. During recovery, cooling is observed to facilitate decreases in sweat rate, heart rate, rectal temperature and forearm blood flow and enhance the increase in average temperature. Cooling had no effect on plasma protein, osmotic or electrolyte shifts, and decreased plasma volume losses. The findings indicate the effectiveness of moderate head cooling for the improvement of human performance during exercise in heat.

A Brief Mindfulness Meditation Training Increases Pain Threshold and Accelerates Modulation of Response to Tonic Pain in an Experimental Study.

PubMed

Reiner, Keren; Granot, Michal; Soffer, Eliran; Lipsitz, Joshua Dan

2016-04-01

Research shows that mindfulness meditation (MM) affects pain perception; however, studies have yet to measure patterns of change over time. We examined effects of MM on perception of experimental heat pain using multiple psychophysical indices, including pattern of change in response to tonic painful stimuli. We also tested the potential moderating role of baseline mindfulness. Forty participants were randomly assigned to a brief MM training or control group. We assessed: a) heat pain threshold (HPT), b) temperature which induces pain at a fixed, target intensity level, and c) response pattern over time to tonic heat pain. Compared to control group, the MM group showed increased HPT and more rapid attenuation of pain intensity for tonic pain stimuli. Moderation analyses indicated that baseline mindfulness moderated effects of MM on HPT. A brief MM intervention appears to affect perception of experimental pain both by increasing pain threshold and accelerating modulation of response. Findings may help elucidate mechanisms of MM for chronic pain. © 2015 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Interaction of moderate UV-B exposure and temperature on the formation of structurally different flavonol glycosides and hydroxycinnamic acid derivatives in kale (Brassica oleracea var. sabellica).

PubMed

Neugart, Susanne; Fiol, Michaela; Schreiner, Monika; Rohn, Sascha; Zrenner, Rita; Kroh, Lothar W; Krumbein, Angelika

2014-05-07

Kale has a high number of structurally different flavonol glycosides and hydroxycinnamic acid derivatives. In this study we investigated the interaction of moderate UV-B radiation and temperature on these compounds. Kale plants were grown at daily mean temperatures of 5 or 15 °C and were exposed to five subsequent daily doses (each 0.25 kJ m(-2) d(-1)) of moderate UV-B radiation at 1 d intervals. Of 20 phenolic compounds, 11 were influenced by an interaction of UV-B radiation and temperature, e.g., monoacylated quercetin glycosides. Concomitantly, enhanced mRNA expression of flavonol 3'- hydroxylase showed an interaction of UV-B and temperature, highest at 0.75 kJ m(-2) and 15 °C. Kaempferol glycosides responded diversely and dependent on, e.g., the hydroxycinnamic acid residue. Compounds containing a catechol structure seem to be favored in the response to UV-B. Taken together, subsequent exposure to moderate UV-B radiation is a successful tool for enhancing the flavonoid profile of plants, and temperature should be considered.

Interactive effects of ocean acidification and warming on coral reef associated epilithic algal communities under past, present-day and future ocean conditions

NASA Astrophysics Data System (ADS)

Vogel, N.; Cantin, N. E.; Strahl, J.; Kaniewska, P.; Bay, L.; Wild, C.; Uthicke, S.

2016-06-01

Epilithic algal communities play critical ecological roles on coral reefs, but their response to individual and interactive effects of ocean warming (OW) and ocean acidification (OA) is still largely unknown. We investigated growth, photosynthesis and calcification of early epilithic algal community assemblages exposed for 6 months to four temperature profiles (-1.1, ±0.0, +0.9, +1.6 °C) that were crossed with four carbon dioxide partial pressure (pCO2) levels (360, 440, 650, 940 µatm), under flow-through conditions and natural light regimes. Additionally, we compared the cover of heavily calcified crustose coralline algae (CCA) and lightly calcified red algae of the genus Peyssonnelia among treatments. Increase in cover of epilithic communities showed optima under moderately elevated temperatures and present pCO2, while cover strongly decreased under high temperatures and high-pCO2 conditions, particularly due to decreasing cover of CCA. Similarly, community calcification rates were strongly decreased at high pCO2 under both measured temperatures. While final cover of CCA decreased under high temperature and pCO2 (additive negative effects), cover of Peyssonnelia spp. increased at high compared to annual average and moderately elevated temperatures. Thus, cover of Peyssonnelia spp. increased in treatment combinations with less CCA, which was supported by a significant negative correlation between organism groups. The different susceptibility to stressors most likely derived from a different calcification intensity and/or mineral. Notably, growth of the epilithic communities and final cover of CCA were strongly decreased under reduced-pCO2 conditions compared to the present. Thus, CCA may have acclimatized from past to present-day pCO2 conditions, and changes in carbonate chemistry, regardless in which direction, negatively affect them. However, if epilithic organisms cannot further acclimatize to OW and OA, the interacting effects of both factors may change epilithic communities in the future, thereby likely leading to reduced reef stability and recovery.

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.

The electrical conductivity during incipient melting in the oceanic low velocity zone

PubMed Central

Sifré, David; Gardés, Emmanuel; Massuyeau, Malcolm; Hashim, Leila; Hier-Majumder, Saswata; Gaillard, Fabrice

2014-01-01

A low viscosity layer in the upper mantle, the Asthenosphere, is a requirement for plate tectonics1. The seismic low velocities and the high electrical conductivities of the Asthenosphere are attributed either to sub-solidus water-related defects in olivine minerals2-4 or to a few volume percents of partial melt5-8 but these two interpretations have shortcomings: (1) The amount of H2O stored in olivine is not expected to be higher than 50 ppm due to partitioning with other mantle phases9, including pargasite amphibole at moderate temperatures10, and partial melting at high temperatures9; (2) elevated melt volume fractions are impeded by the too cold temperatures prevailing in the Asthenosphere and by the high melt mobility that can lead to gravitational segregation11,12. Here we determined the electrical conductivity of CO2-H2O-rich melts, typically produced at the onset of mantle melting. Electrical conductivity modestly increases with moderate amounts of H2O and CO2 but it dramatically increases as CO2 content exceeds 6 wt% in the melt. Incipient melts, long-expected to prevail in the asthenosphere10,13-15, can therefore trigger its high electrical conductivities. Considering depleted and enriched mantle abundances in H2O and CO2 and their effect on the petrology of incipient melting, we calculated conductivity profiles across the Asthenosphere for various plate ages. Several electrical discontinuities are predicted and match geophysical observations in a consistent petrological and geochemical framework. In moderately aged plates (>5Ma), incipient melts most likely trigger both the seismic low velocities and the high electrical conductivities in the upper part of the asthenosphere, whereas for young plates4, where seamount volcanism occurs6, higher degree of melting is expected. PMID:24784219

Electrical conductivity during incipient melting in the oceanic low-velocity zone.

PubMed

Sifré, David; Gardés, Emmanuel; Massuyeau, Malcolm; Hashim, Leila; Hier-Majumder, Saswata; Gaillard, Fabrice

2014-05-01

The low-viscosity layer in the upper mantle, the asthenosphere, is a requirement for plate tectonics. The seismic low velocities and the high electrical conductivities of the asthenosphere are attributed either to subsolidus, water-related defects in olivine minerals or to a few volume per cent of partial melt, but these two interpretations have two shortcomings. First, the amount of water stored in olivine is not expected to be higher than 50 parts per million owing to partitioning with other mantle phases (including pargasite amphibole at moderate temperatures) and partial melting at high temperatures. Second, elevated melt volume fractions are impeded by the temperatures prevailing in the asthenosphere, which are too low, and by the melt mobility, which is high and can lead to gravitational segregation. Here we determine the electrical conductivity of carbon-dioxide-rich and water-rich melts, typically produced at the onset of mantle melting. Electrical conductivity increases modestly with moderate amounts of water and carbon dioxide, but it increases drastically once the carbon dioxide content exceeds six weight per cent in the melt. Incipient melts, long-expected to prevail in the asthenosphere, can therefore produce high electrical conductivities there. Taking into account variable degrees of depletion of the mantle in water and carbon dioxide, and their effect on the petrology of incipient melting, we calculated conductivity profiles across the asthenosphere for various tectonic plate ages. Several electrical discontinuities are predicted and match geophysical observations in a consistent petrological and geochemical framework. In moderately aged plates (more than five million years old), incipient melts probably trigger both the seismic low velocities and the high electrical conductivities in the upper part of the asthenosphere, whereas in young plates, where seamount volcanism occurs, a higher degree of melting is expected.

Effects of high ambient temperature on urea-nitrogen recycling in lactating dairy cows.

PubMed

Obitsu, Taketo; Kamiya, Mitsuru; Kamiya, Yuko; Tanaka, Masahito; Sugino, Toshihisa; Taniguchi, Kohzo

2011-08-01

Effects of exposure to hot environment on urea metabolism were studied in lactating Holstein cows. Four cows were fed ad libitum a total mixed ration and housed in a temperature-controlled chamber at constant moderate (18°C) or high (28°C) ambient temperatures in a cross-over design. Urea nitrogen (N) kinetics was measured by determining urea isotopomer in urine after single injection of [(15) N(2) ]urea into the jugular vein. Both dry matter intake and milk yield were decreased under high ambient temperature. Intakes of total N and digestible N were decreased under high ambient temperature but urinary urea-N excretion was increased. The ratio of urea-N production to digestible N was increased, whereas the proportion of gut urea-N entry to urea-N production tended to be decreased under high ambient temperature. Neither return to the ornithine cycle, anabolic use nor fecal excretion of urea-N recycled to the gut was affected by ambient temperature. Under high ambient temperature, renal clearance of plasma urea was not affected but the gut clearance was decreased. Increase of urea-N production and reduction of gut urea-N entry, in relative terms, were associated with increased urinary urea-N excretion of lactating dairy cows in higher thermal environments. 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.

EVALUATION OF ROTARY KILN INCINERATOR OPERATION AT LOW TO MODERATE TEMPERATURE CONDITIONS VOLUME 1. TECHNICAL RESULTS

EPA Science Inventory

A test program was performed at the Environmental Protection Agency Incineration Research Facility to study the effectiveness of incineration at low-to-moderate temperatures in decontaminating soils containing organic compounds with different volatilities (boiling points). The da...

Self-assembled 3D zinc borate florets via surfactant assisted synthesis under moderate pressures: Process temperature dependent morphology study

NASA Astrophysics Data System (ADS)

Mahajan, Dhiraj S.; Deshpande, Tushar; Bari, Mahendra L.; Patil, Ujwal D.; Narkhede, Jitendra S.

2018-04-01

In the present study, we prepared zinc borates using aqueous phase synthesis under moderate pressures (MP) (<150 psi) with ethanol as a co-solvent in the presence of a quaternary ammonium surfactant-Cetyltrimethylammonium bromide (CTAB). 3D morphologies of self-assembled zinc borate (Zn(H2O)B2O4 · 0.12 H2O, Zn3B6O12 · 3.5H2O, ZnB2O4) resembling flower-like structures were obtained by varying temperature under moderate pressure conditions. Synthesized zinc borates’ florets were morphologically characterized by Field Emission Scanning Electron Microscopy. The x-ray diffractions of borate species reveal rhombohydra, monoclinic and cubic phases of zinc borate crystals as a function of process temperature. Additionally, thermal analysis confirms excellent dehydration/degradation behavior for the zinc borate crystals synthesized at moderate pressures and elevated temperatures and could be utilized as potential flame retardant fillers in the polymer matrices.

Plasma properties of driver gas following interplanetary shocks observed by ISEE-3

NASA Technical Reports Server (NTRS)

Zwickl, R. D.; Asbridge, J. R.; Bame, S. J.; Feldman, W. C.; Gosling, J. T.; Smith, E. J.

1983-01-01

Plasma fluid parameters calculated from solar wind and magnetic field data to determine the characteristic properties of driver gas following a select subset of interplanetary shocks were studied. Of 54 shocks observed from August 1978 to February 1980, 9 contained a well defined driver gas that was clearly identifiable by a discontinuous decrease in the average proton temperature. While helium enhancements were present downstream of the shock in all 9 of these events, only about half of them contained simultaneous changes in the two quantities. Simultaneous with the drop in proton temperature the helium and electron temperature decreased abruptly. In some cases the proton temperature depression was accompanied by a moderate increase in magnetic field magnitude with an unusually low variance, by a small decrease in the variance of the bulk velocity, and by an increase in the ratio of parallel to perpendicular temperature. The cold driver gas usually displayed a bidirectional flow of suprathermal solar wind electrons at higher energies.

Plasma properties of driver gas following interplanetary shocks observed by ISEE-3

NASA Technical Reports Server (NTRS)

Zwickl, R. D.; Ashbridge, J. R.; Bame, S. J.; Feldman, W. C.; Gosling, J. T.; Smith, E. J.

1982-01-01

Plasma fluid parameters calculated from solar wind and magnetic field data obtained on ISEE 3 were studied. The characteristic properties of driver gas following interplanetary shocks was determined. Of 54 shocks observed from August 1978 to February 1980, nine contained a well defined driver gas that was clearly identifiable by a discontinuous decrease in the average proton temperature across a tangential discontinuity. While helium enhancements were present in all of nine of these events, only about half of them contained simultaneous changes in the two quantities. Often the He/H ratio changed over a period of minutes. Simultaneous with the drop in proton temperature the helium and electron temperature decreased abruptly. In some cases the proton temperature depression was accompanied by a moderate increase in magnetic field magnitude with an unusually low variance and by an increase in the ratio of parallel to perpendicular temperature. The drive gas usually displayed a bidirectional flow of suprathermal solar wind electrons at higher energies.

Algal-Based Renewable Energy for Nevada

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

Fritsen, Christian

2017-03-31

To help in the overall evaluation of the potential for growing algal biomass in high productivity systems, we conducted a study that evaluated water from geothermal sources and cultivated mixed consortia from hot springs in Nevada, we evaluated their growth at moderately high varying temperatures and then evaluated potential manipulations that could possibly increase their biomass and oleaginous production. Studies were conducted at scales ranging from the laboratory benchtop to raceways in field settings. Mixed consortia were readily grown at all scales and growth could be maintained in Nevada year round. Moderate productivities were attained even during the shoulder seasons-more » where temperature control was maintained by hot water and seasonally cold temperatures when there was still plentiful solar radiation. The results enhance the prospects for economic feasibility of developing algal based industries in areas with geothermal energy or even other large alternative sources of heat that are not being used for other purposes. The public may benefit from such development as a means for economic development as well as development of industries for alternative energy and products that do not rely on fossil fuels.« less

Association between Weather-Related Factors and Cardiac Arrest of Presumed Cardiac Etiology: A Prospective Observational Study Based on Out-of-Hospital Care Data.

PubMed

Hensel, Mario; Geppert, Daniel; Kersten, Jan F; Stuhr, Markus; Lorenz, Jürgen; Wirtz, Sebastian; Kerner, Thoralf

2018-01-01

The objective of this study was to determine the association between weather-related factors and out-of-hospital cardiac arrest (OHCA) of presumed cardiac etiology. This was a prospective observational study performed in a prehospital setting. Data from the Emergency Medical Service in Hamburg (Germany) and data from the local weather station were evaluated over a 5-year period. Weather data (temperature, humidity, air pressure, wind speed) were obtained every minute and matched with the associated rescue mission data. Lowess-Regression analysis was performed to assess the relationship between the above-mentioned weather-related factors and OHCA of presumed cardiac etiology. Additionally, varying measuring-ranges were defined for each weather-related factor in order to compare them with each other with regard to the probability of occurrence of OHCA. During the observation period 1,558 OHCA with presumed cardiac etiology were registered (age: 67 ± 19 yrs; 62% male; hospital admission: 37%; survival to hospital discharge: 6.7%). Compared to moderate temperatures (5 - 25°C), probability of OHCA-occurrence increased significantly at temperatures above 25°C (p = 0.028) and below 5°C p = 0.011). Regarding air humidity, probability of OHCA-occurrence increased below a threshold-value of 75% compared to values above this cut-off (p = 0.006). Decreased probability was seen at moderate atmospheric pressure (1000 hPa - 1020 hPa), whereas increased probability was seen above 1020 hPa (p = 0.023) and below 1000 hPa (p = 0.035). Probability of OHCA-occurrence increased continuously with increasing wind speed (p < 0.001). There are associations between several weather-related factors such as temperature, humidity, air pressure, and wind speed, and occurrence of OHCA of presumed cardiac etiology. Particularly dangerous seem to be cold weather, dry air and strong wind.

Impact of climate change on cold hardiness of Douglas-fir (Pseudotsuga menziesii): environmental and genetic considerations.

PubMed

Bansal, Sheel; St Clair, J Bradley; Harrington, Constance A; Gould, Peter J

2015-10-01

The success of conifers over much of the world's terrestrial surface is largely attributable to their tolerance to cold stress (i.e., cold hardiness). Due to an increase in climate variability, climate change may reduce conifer cold hardiness, which in turn could impact ecosystem functioning and productivity in conifer-dominated forests. The expression of cold hardiness is a product of environmental cues (E), genetic differentiation (G), and their interaction (G × E), although few studies have considered all components together. To better understand and manage for the impacts of climate change on conifer cold hardiness, we conducted a common garden experiment replicated in three test environments (cool, moderate, and warm) using 35 populations of coast Douglas-fir (Pseudotsuga menziesii var. menziesii) to test the hypotheses: (i) cool-temperature cues in fall are necessary to trigger cold hardening, (ii) there is large genetic variation among populations in cold hardiness that can be predicted from seed-source climate variables, (iii) observed differences among populations in cold hardiness in situ are dependent on effective environmental cues, and (iv) movement of seed sources from warmer to cooler climates will increase risk to cold injury. During fall 2012, we visually assessed cold damage of bud, needle, and stem tissues following artificial freeze tests. Cool-temperature cues (e.g., degree hours below 2 °C) at the test sites were associated with cold hardening, which were minimal at the moderate test site owing to mild fall temperatures. Populations differed 3-fold in cold hardiness, with winter minimum temperatures and fall frost dates as strong seed-source climate predictors of cold hardiness, and with summer temperatures and aridity as secondary predictors. Seed-source movement resulted in only modest increases in cold damage. Our findings indicate that increased fall temperatures delay cold hardening, warmer/drier summers confer a degree of cold hardiness, and seed-source movement from warmer to cooler climates may be a viable option for adapting coniferous forest to future climate. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Solid methane in neutron radiation: Cryogenic moderators and cometary cryo volcanism

NASA Astrophysics Data System (ADS)

Kirichek, O.; Lawson, C. R.; Jenkins, D. M.; Ridley, C. J. T.; Haynes, D. J.

2017-12-01

The effect of ionizing radiation on solid methane has previously been an area of interest in the astrophysics community. In the late 1980s this interest was further boosted by the possibility of using solid methane as a moderating medium in spallation neutron sources. Here we present test results of solid methane moderators commissioned at the ISIS neutron source, and compare them with a model based on the theory of thermal explosion. Good agreement between the moderator test data and our model suggests that the process of radiolysis defect recombination happens at two different temperature ranges: the ;lower temperature; recombination process occurs at around 20 K, with the ;higher temperature; process taking place between 50 and 60 K. We discuss consequences of this mechanism for the designing and operation of solid methane moderators used in advanced neutron sources. We also discuss the possible role of radiolysis defect recombination processes in cryo-volcanism on comets, and suggest an application based on this phenomenon.

Finite temperature dynamics of a Holstein polaron: The thermo-field dynamics approach

NASA Astrophysics Data System (ADS)

Chen, Lipeng; Zhao, Yang

2017-12-01

Combining the multiple Davydov D2 Ansatz with the method of thermo-field dynamics, we study finite temperature dynamics of a Holstein polaron on a lattice. It has been demonstrated, using the hierarchy equations of motion method as a benchmark, that our approach provides an efficient, robust description of finite temperature dynamics of the Holstein polaron in the simultaneous presence of diagonal and off-diagonal exciton-phonon coupling. The method of thermo-field dynamics handles temperature effects in the Hilbert space with key numerical advantages over other treatments of finite-temperature dynamics based on quantum master equations in the Liouville space or wave function propagation with Monte Carlo importance sampling. While for weak to moderate diagonal coupling temperature increases inhibit polaron mobility, it is found that off-diagonal coupling induces phonon-assisted transport that dominates at high temperatures. Results on the mean square displacements show that band-like transport features dominate the diagonal coupling cases, and there exists a crossover from band-like to hopping transport with increasing temperature when including off-diagonal coupling. As a proof of concept, our theory provides a unified treatment of coherent and incoherent transport in molecular crystals and is applicable to any temperature.

High-temperature magnetostructural transition in van der Waals-layered α - MoCl 3

DOE PAGES

McGuire, Michael A.; Yan, Jiaqiang; Lampen-Kelley, Paula; ...

2017-11-07

Here, the crystallographic and magnetic properties of the cleavable 4d 3 transition metal compound α–MoCl 3 are reported, with a focus on the behavior above room temperature. Crystals were grown by chemical vapor transport and characterized using temperature dependent x-ray diffraction, Raman spectroscopy, and magnetization measurements. A structural phase transition occurs near 585 K, at which the Mo-Mo dimers present at room temperature are broken. A nearly regular honeycomb net of Mo is observed above the transition, and an optical phonon associated with the dimerization instability is identified in the Raman data and in first-principles calculations. The crystals are diamagneticmore » at room temperature in the dimerized state, and the magnetic susceptibility increases sharply at the structural transition. Moderately strong paramagnetism in the high-temperature structure indicates the presence of local moments on Mo. This is consistent with results of spin-polarized density functional theory calculations using the low- and high-temperature structures. Above the magnetostructural phase transition the magnetic susceptibility continues to increase gradually up to the maximum measurement temperature of 780 K, with a temperature dependence that suggests two-dimensional antiferromagnetic correlations.« less

High-temperature magnetostructural transition in van der Waals-layered α -MoCl3

NASA Astrophysics Data System (ADS)

McGuire, Michael A.; Yan, Jiaqiang; Lampen-Kelley, Paula; May, Andrew F.; Cooper, Valentino R.; Lindsay, Lucas; Puretzky, Alexander; Liang, Liangbo; KC, Santosh; Cakmak, Ercan; Calder, Stuart; Sales, Brian C.

2017-11-01

The crystallographic and magnetic properties of the cleavable 4 d3 transition metal compound α -MoCl3 are reported, with a focus on the behavior above room temperature. Crystals were grown by chemical vapor transport and characterized using temperature dependent x-ray diffraction, Raman spectroscopy, and magnetization measurements. A structural phase transition occurs near 585 K, at which the Mo-Mo dimers present at room temperature are broken. A nearly regular honeycomb net of Mo is observed above the transition, and an optical phonon associated with the dimerization instability is identified in the Raman data and in first-principles calculations. The crystals are diamagnetic at room temperature in the dimerized state, and the magnetic susceptibility increases sharply at the structural transition. Moderately strong paramagnetism in the high-temperature structure indicates the presence of local moments on Mo. This is consistent with results of spin-polarized density functional theory calculations using the low- and high-temperature structures. Above the magnetostructural phase transition the magnetic susceptibility continues to increase gradually up to the maximum measurement temperature of 780 K, with a temperature dependence that suggests two-dimensional antiferromagnetic correlations.

Lack of effect of moderate hypothermia on brain tissue oxygenation after acute intracranial hypertension in pigs.

PubMed

Bao, Ying-Hui; Liang, Yu-Min; Gao, Guo-Yi; Jiang, Ji-Yao

2010-02-01

In this study, we explored the effect of moderate hypothermia on brain tissue oxygenation following acute intracranial hypertension in micropigs. Twenty healthy juvenile micropigs weighting 4-6 kg were randomized into two groups: a normothermia group (n = 10) and a moderate hypothermia group (n = 10). The animals were intravenously anesthetized with propofol (4 mg/kg), an endotracheal tube was inserted, and mechanical ventilation was begun. Autologous arterial blood was injected into the left frontal lobe to establish acute intracerebral hematoma and intracranial hypertension (intracranial pressure [ICP] >40 mm Hg) in all animals. Cooling was initiated at 30 min after injection of the blood, and was achieved via the use of an ice bath and ice packs. In the hypothermia group, the brain temperature decreased to 33-34 degrees C. Brain temperature was maintained at 37 +/- 0.3 degrees C in the normothermia group. The ICP, cerebral perfusion pressure (CPP), brain tissue oxygen pressure (P(br)O(2)), brain tissue carbon dioxide pressure (P(br)CO(2)), and brain tissue pH value (pH(br)) were continuously monitored for 3 h in all animals. Compared to normothermia group, ICP values significantly decreased and CPP markedly improved in the hypothermia group (p < 0.05). Further, pH(br) also markedly increased and P(br)CO(2) decreased significantly in the hypothermia group (p < 0.05). However, P(br)O(2) did not statistically significantly improve in the hypothermia group (p > 0.05). In sum, moderate hypothermia significantly decreased ICP, reduced P(br)CO(2), and increased pH(br) values, but did not improve cerebral oxygenation following acute intracranial hypertension.

The effects of moderately high temperature on zeaxanthin accumulation and decay.

PubMed

Zhang, Ru; Kramer, David M; Cruz, Jeffrey A; Struck, Kimberly R; Sharkey, Thomas D

2011-09-01

Moderately high temperature reduces photosynthetic capacities of leaves with large effects on thylakoid reactions of photosynthesis, including xanthophyll conversion in the lipid phase of the thylakoid membrane. In previous studies, we have found that leaf temperature of 40°C increased zeaxanthin accumulation in dark-adapted, intact tobacco leaves following a brief illumination, but did not change the amount of zeaxanthin in light-adatped leaves. To investigate heat effects on zeaxanthin accumulation and decay, zeaxanthin level was monitored optically in dark-adapted, intact tobacco and Arabidopsis thaliana leaves at either 23 or 40°C under 45-min illumination. Heated leaves had more zeaxanthin following 3-min light but had less or comparable amounts of zeaxanthin by the end of 45 min of illumination. Zeaxanthin accumulated faster at light initiation and decayed faster upon darkening in leaves at 40°C than leaves at 23°C, indicating that heat increased the activities of both violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZE). In addition, our optical measurement demonstrated in vivo that weak light enhances zeaxanthin decay relative to darkness in intact leaves of tobacco and Arabidopsis, confirming previous observations in isolated spinach chloroplasts. However, the maximum rate of decay is similar for weak light and darkness, and we used the maximum rate of decay following darkness as a measure of the rate of ZE during steady-state light. A simulation indicated that high temperature should cause a large shift in the pH dependence of the amount of zeaxanthin in leaves because of differential effects on VDE and ZE. This allows for the reduction in ΔpH caused by heat to be offset by increased VDE activity relative to ZE.

One-dimensional soil temperature assimilation experiment based on unscented particle filter and Common Land Model

NASA Astrophysics Data System (ADS)

Fu, Xiao Lei; Jin, Bao Ming; Jiang, Xiao Lei; Chen, Cheng

2018-06-01

Data assimilation is an efficient way to improve the simulation/prediction accuracy in many fields of geosciences especially in meteorological and hydrological applications. This study takes unscented particle filter (UPF) as an example to test its performance at different two probability distribution, Gaussian and Uniform distributions with two different assimilation frequencies experiments (1) assimilating hourly in situ soil surface temperature, (2) assimilating the original Moderate Resolution Imaging Spectroradiometer (MODIS) Land Surface Temperature (LST) once per day. The numerical experiment results show that the filter performs better when increasing the assimilation frequency. In addition, UPF is efficient for improving the soil variables (e.g., soil temperature) simulation/prediction accuracy, though it is not sensitive to the probability distribution for observation error in soil temperature assimilation.

Study of Sea Surface Temperatures changes due to tropical cyclone fanoos in the southwest Bay of Bengal using satellite and argo observations

NASA Astrophysics Data System (ADS)

Krishna Kailasam, Muni

Sea surface temperature (SST) plays an important role in the studies of global climate system and as a boundary condition for operational numerical forecasts. Estimation of SST has tra-ditionally been performed with satellite based sensors operating in the infrared (IR) portion of the electromagnetic spectrum, where the ocean emissivity is close to unity. The National Oceanic and Atmospheric Administration (NOAA) satellite series, the GOES Imagers on the Geostationary Operational Environmental Satellites, the Along Track Scanning Radiometer (ATSR) on the European Remote Sensing satellites and the Moderate Resolution Imaging Spectroradiometer (MODIS) on the NASA EOS platform are successful examples of IR sen-sors currently used for operational SST retrievals. Significant progress in SST retrieval from remote sensing data came with the introduction of a new low-frequency channel (10.7 GHz) on microwave (MW) sensors. The anthropogenic effects over a period of time resulted in increase of infrared absorbers such as greenhouse gases and absorbing aerosol would produce increase of both daytime maximum and nighttime minimum temperatures. In contrast, the increases of visible reflectors such as sulfate aerosols and low cloud amount would result in a decrease of the daytime maximum temperature. Solar radiation, wind stress and vertical mixing are known to be the three major factors impacting the SST seasonal variations. In the present study, impact of absorbing aerosols on the sea surface temperature (SST) over Bay of Bengal (BoB) region was investigated. Increased aerosol loading over BoB was observed due to advection of aerosols from continental region consisting of absorbing particles primarily from dust and biomass burning. This increased loading over BoB resulted in reduction of surface reaching solar radiation. Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) de-rived SST over BoB showed negative correlation with OMI-Aerosol Index (AI) (R = 0.87) and Terra/Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) AOD550 (R = 0.77) suggesting reduction in SST due to absorption of incoming solar radiation by aerosols.

Association of Temperature and Historical Dynamics of Malaria in the Republic of Korea, Including Reemergence in 1993

NASA Technical Reports Server (NTRS)

Linthicum, Kenneth J.; Anyamba, Assaf; Killenbeck, Bradley; Lee, Won-Ja; Lee, Hee Choon S.; Klein, Terry A.; Kim, Heung-Chul; Pavlin, Julie A.; Britch, Seth C.; Small, Jennifer;

Cell-intrinsic mechanisms of temperature compensation in a grasshopper sensory receptor neuron

PubMed Central

Roemschied, Frederic A; Eberhard, Monika JB; Schleimer, Jan-Hendrik; Ronacher, Bernhard; Schreiber, Susanne

2014-01-01

Changes in temperature affect biochemical reaction rates and, consequently, neural processing. The nervous systems of poikilothermic animals must have evolved mechanisms enabling them to retain their functionality under varying temperatures. Auditory receptor neurons of grasshoppers respond to sound in a surprisingly temperature-compensated manner: firing rates depend moderately on temperature, with average Q10 values around 1.5. Analysis of conductance-based neuron models reveals that temperature compensation of spike generation can be achieved solely relying on cell-intrinsic processes and despite a strong dependence of ion conductances on temperature. Remarkably, this type of temperature compensation need not come at an additional metabolic cost of spike generation. Firing rate-based information transfer is likely to increase with temperature and we derive predictions for an optimal temperature dependence of the tympanal transduction process fostering temperature compensation. The example of auditory receptor neurons demonstrates how neurons may exploit single-cell mechanisms to cope with multiple constraints in parallel. DOI: http://dx.doi.org/10.7554/eLife.02078.001 PMID:24843016

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.

Stresses in sulfuric acid anodized coatings on aluminum

NASA Technical Reports Server (NTRS)

Alwitt, R. S.; Xu, J.; Mcclung, R. C.

1993-01-01

Stresses in porous anodic alumina coatings have been measured for specimens stabilized in air at different temperatures and humidities. In ambient atmosphere the stress is tensile after anodic oxidation and is compressive after sealing. Exposure to dry atmosphere causes the stress to change to strongly tensile, up to 110 MPa. The stress increase is proportional to the loss of water from the coating. These changes are reversible with changes in humidity. Similar reversible effects occur upon moderate temperature changes. The biaxial modulus of the coating is about 100 GPa.

Tandem catalysis for the production of alkyl lactates from ketohexoses at moderate temperatures

DOE PAGES

Orazov, Marat; Davis, Mark E.

2015-09-08

Retro-aldol reactions have been implicated as the limiting steps in catalytic routes to convert biomass-derived hexoses and pentoses into valuable C2, C3, and C4 products such as glycolic acid, lactic acid, 2-hydroxy-3-butenoic acid, 2,4-dihydroxybutanoic acid, and alkyl esters thereof. Due to a lack of efficient retro-aldol catalysts, most previous investigations of catalytic pathways involving these reactions were conducted at high temperatures (≥160 °C). Here, we report moderate-temperature (around 100 °C) retro-aldol reactions of various hexoses in aqueous and alcoholic media with catalysts traditionally known for their capacity to catalyze 1,2-intramolecular carbon shift (1,2-CS) reactions of aldoses, i.e., various molybdenum oxidemore » and molybdate species, nickel(II) diamine complexes, alkali-exchanged stannosilicate molecular sieves, and amorphous TiO2–SiO2 coprecipitates. Solid Lewis acid cocatalysts that are known to catalyze 1,2-intramolecular hydride shift (1,2-HS) reactions that enable the formation of α-hydroxy carboxylic acids from tetroses, trioses, and glycolaldehyde, but cannot readily catalyze retro-aldol reactions of hexoses and pentoses at these moderate temperatures, are shown to be compatible with the aforementioned retro-aldol catalysts. The combination of a distinct retro-aldol catalyst with a 1,2-HS catalyst enables lactic acid and alkyl lactate formation from ketohexoses at moderate temperatures (around 100 °C), with yields comparable to best-reported chemocatalytic examples at high temperature conditions (≥160 °C). The use of moderate temperatures enables numerous desirable features such as lower pressure and significantly less catalyst deactivation.« less

Effects of seawater pCO2 and temperature on calcification and productivity in the coral genus Porites spp.: an exploration of potential interaction mechanisms

NASA Astrophysics Data System (ADS)

Cole, C.; Finch, A. A.; Hintz, C.; Hintz, K.; Allison, N.

2018-06-01

Understanding how rising seawater pCO2 and temperatures impact coral aragonite accretion is essential for predicting the future of reef ecosystems. Here, we report 2 long-term (10-11 month) studies assessing the effects of temperature (25 and 28 °C) and both high and low seawater pCO2 (180-750 μatm) on the calcification, photosynthesis and respiration of individual massive Porites spp. genotypes. Calcification rates were highly variable between genotypes, but high seawater pCO2 reduced calcification significantly in 4 of 7 genotypes cultured at 25 °C but in only 1 of 4 genotypes cultured at 28 °C. Increasing seawater temperature enhanced calcification in almost all corals, but the magnitude of this effect was seawater pCO2 dependent. The 3 °C temperature increase enhanced calcification rate on average by 3% at 180 μatm, by 35% at 260 μatm and by > 300% at 750 μatm. The rate increase at high seawater pCO2 exceeds that observed in inorganic aragonites. Responses of gross/net photosynthesis and respiration to temperature and seawater pCO2 varied between genotypes, but rates of all these processes were reduced at the higher seawater temperature. Increases in seawater temperature, below the thermal stress threshold, may mitigate against ocean acidification in this coral genus, but this moderation is not mediated by an increase in net photosynthesis. The response of coral calcification to temperature cannot be explained by symbiont productivity or by thermodynamic and kinetic influences on aragonite formation.

Elevated Temperature and 6-7 Year Outcome of Neonatal Encephalopathy

PubMed Central

Laptook, Abbot R.; McDonald, Scott A.; Shankaran, Seetha; Stephens, Bonnie E.; Vohr, Betty R.; Guillet, Ronnie; Higgins, Rosemary D.; Das, Abhik

2013-01-01

OBJECTIVE Determine if higher temperature after hypoxia-ischemia is associated with death or IQ < 70 at 6-7 yr among infants treated with intensive care without hypothermia. DESIGN/METHODS Control infants (non-cooled, n=106) of the NICHD Neonatal Research Network hypothermia trial had serial esophageal and skin temperatures over 72hrs. Each infant's temperature was ranked to derive an average of the upper and lower quartile, and median of each site. Temperatures were used in logistic regressions to determine adjusted associations with death or IQ < 70 at 6-7yrs. Secondary outcomes were death, IQ < 70, and moderate/severe CP. IQ and motor function were assessed with Wechsler Scales for Children and Gross Motor Function Classification System. Results are odds ratio (OR, per °C increment within the quartile or median) and 95% confidence interval (CI). RESULTS Primary outcome was available for 89 infants. At 6-7yrs death or IQ < 70 occurred in 54 infants (37 deaths, 17 survivors with IQ < 70) and moderate/severe CP in 15 infants. Death or IQ < 70 was associated with the upper quartile average of esophageal (OR 7.3, 95% CI 2.0-26.3) and skin temperature (OR 3.5, 95% 1.2-10.4). CP was associated with the upper quartile average of esophageal (OR 12.5, 95% CI 1.02-155) and skin temperature (OR 10.3, 95% 1.3-80.2). CONCLUSIONS Among non-cooled infants of a randomized trial, elevated temperatures during the first post-natal days are associated with increase odds of a worse outcome at 6-7yrs. PMID:23595408

Northwestern Pacific typhoon intensity controlled by changes in ocean temperatures.

PubMed

Mei, Wei; Xie, Shang-Ping; Primeau, François; McWilliams, James C; Pasquero, Claudia

2015-05-01

Dominant climatic factors controlling the lifetime peak intensity of typhoons are determined from six decades of Pacific typhoon data. We find that upper ocean temperatures in the low-latitude northwestern Pacific (LLNWP) and sea surface temperatures in the central equatorial Pacific control the seasonal average lifetime peak intensity by setting the rate and duration of typhoon intensification, respectively. An anomalously strong LLNWP upper ocean warming has favored increased intensification rates and led to unprecedentedly high average typhoon intensity during the recent global warming hiatus period, despite a reduction in intensification duration tied to the central equatorial Pacific surface cooling. Continued LLNWP upper ocean warming as predicted under a moderate [that is, Representative Concentration Pathway (RCP) 4.5] climate change scenario is expected to further increase the average typhoon intensity by an additional 14% by 2100.

Recrystallization method to selenization of thin-film Cu(In,Ga)Se.sub.2 for semiconductor device applications

DOEpatents

Albin, David S.; Carapella, Jeffrey J.; Tuttle, John R.; Contreras, Miguel A.; Gabor, Andrew M.; Noufi, Rommel; Tennant, Andrew L.

1995-07-25

A process for fabricating slightly Cu-poor thin-films of Cu(In,Ga)Se.sub.2 on a substrate for semiconductor device applications includes the steps of forming initially a slightly Cu-rich, phase separated, mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se on the substrate in solid form followed by exposure of the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture to an overpressure of Se vapor and (In,Ga) vapor for deposition on the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture while simultaneously increasing the temperature of the solid mixture toward a recrystallization temperature (about 550.degree. C.) at which Cu(In,Ga)Se.sub.2 is solid and Cu.sub.x Se is liquid. The (In,Ga) flux is terminated while the Se overpressure flux and the recrystallization temperature are maintained to recrystallize the Cu.sub.x Se with the (In, Ga) that was deposited during the temperature transition and with the Se vapor to form the thin-film of slightly Cu-poor Cu.sub.x (In,Ga).sub.y Se.sub.z. The initial Cu-rich, phase separated large grain mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se can be made by sequentially depositing or co-depositing the metal precursors, Cu and (In, Ga), on the substrate at room temperature, ramping up the thin-film temperature in the presence of Se overpressure to a moderate anneal temperature (about 450.degree. C.) and holding that temperature and the Se overpressure for an annealing period. A nonselenizing, low temperature anneal at about 100.degree. C. can also be used to homogenize the precursors on the substrates before the selenizing, moderate temperature anneal.

Recent developments in polyimide and bismaleimide adhesives

NASA Technical Reports Server (NTRS)

Politi, R. E.

1985-01-01

Research on high temperature resin systems has intensified. In the Aerospace Industry, the motivation for this increased activity has been to replace heat resistant alloys of aluminum, stainless steel and titanium by lighter weight glass and carbon fiber reinforced composites. Applications for these structures include: (1) engine nacelles involving long time exposure (thousands of hours) to temperatures in the 150 to 300 C range, (2) supersonic military aircraft involving moderately long exposure (hundreds of hours) to temperatures of 150 to 200 C, and (3) missile applications involving only brief exposure (seconds or minutes) to temperatures up to 500 C and above. Because of fatigue considerations, whenever possible, it is preferable to bond rather than mechanically fasten composite structures. For this reason, the increased usage of high temperature resin matrix systems for composites has necessitated the devlopment of compatible and equally heat stable adhesive systems. The performance of high temperature epoxy, epoxy phenolic and condensation polyimide adhesives is reviewed. This is followed by a discussion of three recently developed types of adhesives: (1) condensation reaction polyimides having improved processing characteristics; (2) addition reaction polyimides; and (3) bismaleimides.

Use of near-IR to monitor the influence of external heating on dental composite photopolymerization.

PubMed

Trujillo, Marianela; Newman, Sheldon M; Stansbury, Jeffrey W

2004-10-01

This study was conducted to determine the effect of modest external heating on the photopolymerization kinetics and conversion of commercial dental composite restorative materials. A transmission-mode, real-time near-infrared spectroscopic technique was used to monitor the photopolymerization process in the composite materials at various temperatures between 23 and 70 degrees C. Several light curing units, differing in spectral output and power densities were compared at the different cure temperatures. Several significantly different commercial composites were compared for their response. Regardless of the curing light or composite material used, photopolymerization at a moderate curing temperature of 54.5 degrees C resulted in significantly higher immediate and final conversion values compared with room temperature photocuring. Contrary to the room temperature cured materials, at the elevated cure temperature the extent of post-cure was minor and different curing lights produced very uniform conversion values within a given material. The time required to reach a given level of conversion, established as full conversion with the room temperature cure, was reduced typically by 80-90% using the elevated curing conditions. Complementary kinetic studies confirmed the effect of cure temperature on increasing the polymerization rate in dental composites as significant. Increasing the temperature of composite resin within potentially biologically compatible limits can significantly influences resin polymerization. These increased rates and conversion could lead to improved properties of composite restorative materials.

Modeling the effects of light, carbon dioxide, and temperature on the growth of potato

NASA Technical Reports Server (NTRS)

Yandell, B. S.; Najar, A.; Wheeler, R.; Tibbitts, T. W.

1988-01-01

This study examined the effects of light, temperature and carbon dioxide on the growth of potato (Solanum tuberosum L.) in a controlled environment in order to ascertain the best growing conditions for potato in life support systems in space. 'Norland' and 'Russet Burbank' were grown in 6-L pots of peat-vermiculite for 56 d in growth chambers at the University of Wisconsin Biotron. Environmental factor levels included continuous light (24-h photoperiod) at 250, 400, and 550 micromoles m-2 s-1 PPF; constant temperature at 16, 20, and 24 degrees C; and CO2 at approximately 400, 1000, and 1600 microliters L-1. Separate effects analysis and ridge analysis provided a means to examine the effects of individual environmental factors and to determine combinations of factors that are expected to give the best increases in yields over the central design point. The response surface of Norland indicated that tuber yields were highest with moderately low temperature (18.7 degrees C), low CO2 (400 microliters L-1) and high light (550 micromoles m-2 s-1 PPF). These conditions also favored shorter stem growth. Russet Burbank tuber yields were highest at moderately low temperature (17.5 degrees C), high CO2 (1600 microliters L-1) and medium analyses will be used to project the most efficient conditions for growth of potatoes in closed ecological life support systems (CELSS) in space colonies.

Hsp60 expression profiles in the reef-building coral Seriatopora caliendrum subjected to heat and cold shock regimes.

PubMed

Seveso, Davide; Montano, Simone; Strona, Giovanni; Orlandi, Ivan; Galli, Paolo; Vai, Marina

2016-08-01

Climate changes have increased the intensity/frequency of extreme thermal events, which represent serious threats to the health of reef-building corals. Since the vulnerability of corals exposed to thermal stresses are related to their ability to regulate Heat shock proteins (Hsps), we have analyzed together the time related expression profiles of the mitochondrial Hsp60 and the associated changes in tissue pigmentation in Seriatopora caliendrum subjected to 48 h of heat and cold treatments characterized by moderate (±2 °C) and severe (±6 °C) shocks. For the first time, an Hsp60 response was observed in a scleractinian coral exposed to cold stresses. Furthermore, the Hsp60 modulations and the changes in the tissue coloration were found to be specific for each treatment. A strong down-regulation at the end of the treatments was observed following both the severe shocks, but only the severe heat stress led to bleaching in concert with the lowest levels of Hsp60, suggesting that a severe heat shock can be more deleterious than an exposure to a severe cold temperature. On the contrary, a moderate cold stress seems to be more harmful than a moderate temperature increase, which could allow coral acclimation. Our results can provide a potential framework for understanding the physiological tolerance of corals under possible future climate changes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Differences between young adults and elderly in thermal comfort, productivity, and thermal physiology in response to a moderate temperature drift and a steady-state condition.

PubMed

Schellen, L; van Marken Lichtenbelt, W D; Loomans, M G L C; Toftum, J; de Wit, M H

2010-08-01

Results from naturally ventilated buildings show that allowing the indoor temperature to drift does not necessarily result in thermal discomfort and may allow for a reduction in energy use. However, for stationary conditions, several studies indicate that the thermal neutral temperature and optimum thermal condition differ between young adults and elderly. There is a lack of studies that describe the effect of aging on thermal comfort and productivity during a moderate temperature drift. In this study, the effect of a moderate temperature drift on physiological responses, thermal comfort, and productivity of eight young adults (age 22-25 year) and eight older subjects (age 67-73 year) was investigated. They were exposed to two different conditions: S1-a control condition; constant temperature of 21.5 degrees C; duration: 8 h; and S2-a transient condition; temperature range: 17-25 degrees C, duration: 8 h, temperature drift: first 4 h: +2 K/h, last 4 h: -2 K/h. The results indicate that thermal sensation of the elderly was, in general, 0.5 scale units lower in comparison with their younger counterparts. Furthermore, the elderly showed more distal vasoconstriction during both conditions. Nevertheless, TS of the elderly was related to air temperature only, while TS of the younger adults also was related to skin temperature. During the constant temperature session, the elderly preferred a higher temperature in comparison with the young adults. Because the stock of fossil fuels is limited, energy savings play an important role. Thermal comfort is one of the most important performance indicators to successfully apply measures to reduce the energy need in buildings. Allowing drifts in indoor temperature is one of the options to reduce the energy demand. This study contributes to the knowledge concerning the effects of a moderate temperature drift and the age of the inhabitants on their thermal comfort.

Thermolabile triose phosphate isomerase in a psychrophilic Clostridium.

NASA Technical Reports Server (NTRS)

Shing, Y. W.; Akagi, J. M.; Himes, R. H.

1972-01-01

It was found that a psychrophilic Clostridium contains a triose phosphate isomerase which is very labile at moderate temperatures. An investigation showed that the optimal growth temperature of the psychrophile was between 15 and 20 deg C. No growth occurred at 25 deg C. The thermostability of the glycolytic enzymes in the cell-free extracts of Clostridium sp. strain 69 was studied. The data obtained show that the triose phosphate isomerase is quite labile at moderate temperatures. The instability of the enzyme is sufficient to explain the low maximum growth temperature of the psychrophile.

Preparation of dual-stimuli-responsive liposomes using methacrylate-based copolymers with pH and temperature sensitivities for precisely controlled release.

PubMed

Sugimoto, Takumi; Yamazaki, Naoko; Hayashi, Takaaki; Yuba, Eiji; Harada, Atsushi; Kotaka, Aki; Shinde, Chiharu; Kumei, Takayuki; Sumida, Yasushi; Fukushima, Mitsuhiro; Munekata, Yuki; Maruyama, Keiichi; Kono, Kenji

2017-07-01

Dual-signal-sensitive copolymers were synthesized by copolymerization of methoxy diethylene glycol methacrylate, methacrylic acid, and lauroxy tetraethylene glycol methacrylate, which respectively provide temperature sensitivity, pH sensitivity, and anchoring to liposome surfaces. These novel copolymers, with water solubility that differs depending on temperature and pH, are soluble in water under neutral pH and low-temperature conditions, but they become water-insoluble and form aggregates under acidic pH and high-temperature conditions. Liposomes modified with these copolymers exhibited enhanced content release at weakly acidic pH with increasing temperature, although no temperature-dependent content release was observed in neutral conditions. Interaction between the copolymers and the lipid monolayer at the air-water interface revealed that the copolymer chains penetrate more deeply into the monolayer with increasing temperature at acidic pH than at neutral pH, where the penetration of copolymer chains was moderate and temperature-independent at neutral pH. Interaction of the copolymer-modified liposomes with HeLa cells demonstrated that the copolymer-modified liposomes were adsorbed quickly and efficiently onto the cell surface and that they were internalized more gradually than the unmodified liposomes through endocytosis. Furthermore, the copolymer-modified liposomes enhanced the content release in endosomes with increasing temperature, but no such temperature-dependent enhancement of content release was observed for unmodified liposomes. Copyright © 2017 Elsevier B.V. All rights reserved.

Projected warming portends seasonal shifts of stream temperatures in the Crown of the Continent Ecosystem, USA and Canada

USGS Publications Warehouse

Jones, Leslie A.; Muhlfeld, Clint C.; Marshall, Lucy A.

2017-01-01

Climate warming is expected to increase stream temperatures in mountainous regions of western North America, yet the degree to which future climate change may influence seasonal patterns of stream temperature is uncertain. In this study, a spatially explicit statistical model framework was integrated with empirical stream temperature data (approximately four million bi-hourly recordings) and high-resolution climate and land surface data to estimate monthly stream temperatures and potential change under future climate scenarios in the Crown of the Continent Ecosystem, USA and Canada (72,000 km2). Moderate and extreme warming scenarios forecast increasing stream temperatures during spring, summer, and fall, with the largest increases predicted during summer (July, August, and September). Additionally, thermal regimes characteristic of current August temperatures, the warmest month of the year, may be exceeded during July and September, suggesting an earlier and extended duration of warm summer stream temperatures. Models estimate that the largest magnitude of temperature warming relative to current conditions may be observed during the shoulder months of winter (April and November). Summer stream temperature warming is likely to be most pronounced in glacial-fed streams where models predict the largest magnitude (> 50%) of change due to the loss of alpine glaciers. We provide the first broad-scale analysis of seasonal climate effects on spatiotemporal patterns of stream temperature in the Crown of the Continent Ecosystem for better understanding climate change impacts on freshwater habitats and guiding conservation and climate adaptation strategies.

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

“Ductile to brittle” transition in thermally stable antigorite gouge at mantle pressures

USGS Publications Warehouse

Proctor, Brooks; Hirth, Greg

2016-01-01

General shear experiments on antigorite-rich serpentinite show a transition from ductile (distributed) to brittle (localized) deformation with increasing temperature from 300°C to 500°C at confining pressures from 1 to 2 GPa. The coefficient of friction associated with slip along fractures decreases from 0.23 to 0.07 with an increase in temperature from 300°C to 500°C. Velocity stepping experiments exhibit a positive rate dependence, as parameterized by a-b values, that decrease modestly with increasing temperature from ~0.015 at 300°C to ~0.01 at 500°C. Fractures contain fine-grained foliated antigorite, and there is no evidence of dehydration. All samples have a moderate foliation and show microstructural evidence for both plastic and brittle deformation mechanisms. Under certain conditions the transition to brittle deformation, at high pressures and temperatures in antigorite, might generate earthquakes, which could explain the occurrence of some intermediate-depth seismicity within subduction zones in serpentinized regions that are too cold to induce dehydration.

Optical characterization of wide-gap detector-grade semiconductors

NASA Astrophysics Data System (ADS)

Elshazly, Ezzat S.

Wide bandgap semiconductors are being widely investigated because they have the potential to satisfy the stringent material requirements of high resolution, room temperature gamma-ray spectrometers. In particular, Cadmium Zinc Telluride (Cd1-xZnxTe, x˜0.1) and Thallium Bromide (TlBr), due to their combination of high resistivity, high atomic number and good electron mobility, have became very promising candidates for use in X- and gamma-ray detectors operating at room temperature. In this study, carrier trapping times were measured in CZT and TlBr as a function of temperature and material quality. Carrier lifetimes and tellurium inclusion densities were measured in detector-grade Cadmium Zinc Telluride (CZT) crystals grown by the High Pressure Bridgman method and Modified Bridgman method. Excess carriers were produced in the material using a pulsed YAG laser with a 1064nm wavelength and 7ns pulse width. Infrared microscopy was used to measure the tellurium defect densities in CZT crystals. The electronic decay was optically measured at room temperature. Spatial mapping of lifetimes and defect densities in CZT was performed to determine the relationship between defect density and electronic decay. A significant and strong correlation was found between the volume fraction of tellurium inclusions and the carrier trapping time. Carrier trapping times and tellurium inclusions were measured in CZT in the temperature range from 300K to 110K and the results were analyzed using a theoretical trapping model. Spatial mapping of carrier trapping times and defect densities in CZT was performed to determine the relationship between defect density and electronic decay. While a strong correlation between trapping time and defect density of tellurium inclusions was observed, there was no significant change in the trap energy. Carrier trapping times were measured in detector grade thallium bromide (TlBr) and compared with the results for cadmium zinc telluride (CZT) in a temperature range from 300K to 110K. The experimental data was analyzed using a trapping model. In CZT, because the majority carrier concentration is close to the intrinsic carrier concentration, the trapping time increases exponentially as the temperature decreases below about 160K. While, in TlBr, the majority carrier concentration is many orders of magnitude greater than the intrinsic carrier concentration and the trapping time followed a 1T temperature dependence over the range of temperatures studied. The results of the model suggest that a moderately deep compensation center, located approximately 200 meV from the middle of the bandgap, could be used to significantly increase the room temperature trapping time in TlBr. The results of this model demonstrate that the room temperature trapping time in TlBr can, in principle, approach 0.1ms through the introduction of a moderately deep compensation level but without decreasing the overall trap concentration. This strategy is not possible in CZT, because the band gap is too small to use a moderately deep compensation level while still maintaining high material resistivity. Carrier trapping times were measured in three polycrystalline TlBr samples produced by melting commercial TlBr beads in a sealed quartz ampoule for two hours at three different temperatures near the melting point. The trapping time decreased with increasing melting temperature, presumably due to the thermal generation of a trap state.

18F-FDG uptake in the colon is modulated by metformin but not associated with core body temperature and energy expenditure.

PubMed

Bahler, Lonneke; Holleman, Frits; Chan, Man-Wai; Booij, Jan; Hoekstra, Joost B; Verberne, Hein J

2017-01-01

Physiological colonic 18F-fluorodeoxyglucose (18F-FDG) uptake is a frequent finding on 18F-FDG positron emission tomography computed tomography (PET-CT). Interestingly, metformin, a glucose lowering drug associated with moderate weight loss, is also associated with an increased colonic 18F-FDG uptake. Consequently, increased colonic glucose use might partly explain the weight losing effect of metformin when this results in an increased energy expenditure and/or core body temperature. Therefore, we aimed to determine whether metformin modifies the metabolic activity of the colon by increasing glucose uptake. In this open label, non-randomized, prospective mechanistic study, we included eight lean and eight overweight males. We measured colonic 18F-FDG uptake on PET-CT, energy expenditure and core body temperature before and after the use of metformin. The maximal colonic 18F-FDG uptake was measured in 5 separate segments (caecum, colon ascendens,-transversum,-descendens and sigmoid). The maximal colonic 18F-FDG uptake increased significantly in all separate segments after the use of metformin. There was no significant difference in energy expenditure or core body temperature after the use of metformin. There was no correlation between maximal colonic 18F-FDG uptake and energy expenditure or core body temperature. Metformin significantly increases colonic 18F-FDG uptake, but this increased uptake is not associated with an increase in energy expenditure or core body temperature. Although the colon might be an important site of the glucose plasma lowering actions of metformin, this mechanism of action does not explain directly any associated weight loss.

Population collapse dynamics in Acropora downingi, an Arabian/Persian Gulf ecosystem-engineering coral, linked to rising temperature.

PubMed

Riegl, Bernhard; Johnston, Matthew; Purkis, Sam; Howells, Emily; Burt, John; Steiner, Sascha C C; Sheppard, Charles R C; Bauman, Andrew

2018-03-05

As in the tropical Atlantic, Acropora populations in the southern Persian/Arabian Gulf plummeted within two decades after having been ecosystem engineers on most wave-exposed reefs since the Pleistocene. Since 1996/1998 live coral cover in the Gulf declined by over 90% in many areas, primarily due to bleaching and diseases caused by rising temperatures. In the formerly dominant table-coral species A. downingi, population dynamics corresponding to disturbance regimes was quantified in three transition matrices (lower disturbance pre-1996; moderate disturbance from 1998 to 2010 and 2013 to 2017, disturbed in 1996/1998, 2010/11/12, 2017). Increased disturbance frequency and severity caused progressive reduction in coral size, cover, and population fecundity. Small size-classes were bolstered more by partial colony mortality than sexual recruitment. Some large corals had a size refuge and resisted die-back but were also lost with increasing disturbance. Matrix and biophysical larval flow models suggested one metapopulation. Southern, Arabian, populations could be connected to northern, Iranian, populations but this connectivity was lost under assumptions of pelagic larval duration at rising temperatures shortened to a third. Then, the metapopulation disintegrated into isolated populations. Connectivity required to avoid extinctions increased exponentially with disturbance frequency and correlation of disturbances across the metapopulation. Populations became unsustainable at eight disturbances in 15 years, when even highest theoretical recruitment no longer compensated mortality. This lethal disturbance frequency was 3-fold that of the moderately disturbed monitoring period and 4-fold of the preceding low-disturbance period-suggesting ongoing shortening of the disturbance-free period. Observed population collapse and environmental changes in the Gulf suggest that A. downingi is heading toward at least functional extinction mainly due to increasingly frequent temperature-induced mortality events, clearly linked to climate change. © 2018 John Wiley & Sons Ltd.

Natural hydrocarbons, urbanization, and urban ozone

NASA Technical Reports Server (NTRS)

Cardelino, C. A.; Chameides, W. L.

1990-01-01

The combined effects of emission control and urbanization, with its concomitant intensification of the urban heat island, on urban ozone concentrations are studied. The effect of temperature on ozone is considered, and attention is given to the temperature effect on ozone photochemistry. Model calculations suggest that ozone concentration enhancements are caused by the effect of temperature on the atmospheric chemistry of peroxyacetyl nitrate, as well as the temperature dependence of natural and anthropogenic hydrocarbon emissions. It is pointed out that, because of the sensitivity of urban ozone to local climatic conditions and the ability of trees to moderate summertime temperatures, the inadvertent removal of trees from urbanization can have an adverse effect on urban ozone concentration, while a temperature increase in the urban heat island caused by urbanization can essentially cancel out the ozone-reducing benefits obtained from a 50-percent reduction in anthropogenic hydrocarbon emissions.

Exploring the role of green and blue infrastructure in reducing temperature in Iskandar Malaysia using remote sensing approach

NASA Astrophysics Data System (ADS)

Kanniah, K. D.; sheikhi, A.; Kang, C. S.

2014-02-01

Development of cities has led to various environmental problems as a consequence of non sustaibale town planning. One of the strategies to make cities a livable place and to achieve low levels of CO2 emissions (low carbon cities or LCC) is the integration of the blue and green infrastructure into the development and planning of new urban areas. Iskandar Malaysia (IM) located in the southern part of Malaysia is a special economic zone that has major urban centres. The planning of these urban centres will incorporate LCC strategies to achieve a sustainable development. The role of green (plants) and blue bodies (lakes and rivers) in moderating temperature in IM have been investigated in the current study. A remotely sensed satellite imagery was used to calculate the vegetation density and land surface temperature (LST). The effect of lakes in cooling the surrounding temperature was also investigated. Results show that increasing vegetation density by 1% can decrease the LST by 0.09°C. As for the water bodies we found as the distance increased from the lake side the temperature also increased about 1.7°C and the reduction in air humidity is 9% as the distance increased to 100 meter away from the lake.

Temperature gating and competing temperature-dependent effects in DNA molecular wires

NASA Astrophysics Data System (ADS)

Wibowo, Denni; Narenji, Alaleh; Kassegne, Sam

2017-02-01

While recent research in electron-transport mechanism on a double strands DNA seems to converge into a consensus, experiments in direct electrical measurements on a long DNA molecules still lead to a conflicting result This study is the continuation of our previous research in electrical characterization of DNA molecular wires, where we furtherly investigate the effects of temperature on the electrical conductivity of DNA molecular wires by measuring its impedance response. We found that at higher temperatures, the expected increase in charge hopping mechanism may account for the decrease in impedance (and hence increase in conductivity) supporting the 'charge hopping mechanism' theory. UV light exposure, on the other hand, causes damage to GC base pairs reducing the path available for hopping mechanism and hence resulting in increased impedance - this again supporting the 'charge hopping mechanism' theory. We also report that λ-DNA molecular wires have differing impedance responses at two temperature regimes: impedance increases between 4 °C - 40 °C and then decreases between 40 °C - melting point (˜110 °C), after which λ-DNA denatures resulting in no current transduction. We submit that the low impedance of λ-DNA molecular wires observed at moderate to high frequencies may have significant implications to the field of DNA-based bionanoelectronics.

Greenland ice sheet surface temperature, melt and mass loss: 2000-06

USGS Publications Warehouse

Hall, D.K.; Williams, R.S.; Luthcke, S.B.; DiGirolamo, N.E.

2008-01-01

A daily time series of 'clear-sky' surface temperature has been compiled of the Greenland ice sheet (GIS) using 1 km resolution moderate-resolution imaging spectroradiometer (MODIS) land-surface temperature (LST) maps from 2000 to 2006. We also used mass-concentration data from the Gravity Recovery and Climate Experiment (GRACE) to study mass change in relationship to surface melt from 2003 to 2006. The mean LST of the GIS increased during the study period by ???0.27??Ca-1. The increase was especially notable in the northern half of the ice sheet during the winter months. Melt-season length and timing were also studied in each of the six major drainage basins. Rapid (<15 days) and sustained mass loss below 2000 m elevation was triggered in 2004 and 2005 as recorded by GRACE when surface melt begins. Initiation of large-scale surface melt was followed rapidly by mass loss. This indicates that surface meltwater is flowing rapidly to the base of the ice sheet, causing acceleration of outlet glaciers, thus highlighting the metastability of parts of the GIS and the vulnerability of the ice sheet to air-temperature increases. If air temperatures continue to rise over Greenland, increased surface melt will play a large role in ice-sheet mass loss.

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

Spatio-temporal modelling of heat stress and climate change implications for the Murray dairy region, Australia.

PubMed

Nidumolu, Uday; Crimp, Steven; Gobbett, David; Laing, Alison; Howden, Mark; Little, Stephen

2014-08-01

The Murray dairy region produces approximately 1.85 billion litres of milk each year, representing about 20 % of Australia's total annual milk production. An ongoing production challenge in this region is the management of the impacts of heat stress during spring and summer. An increase in the frequency and severity of extreme temperature events due to climate change may result in additional heat stress and production losses. This paper assesses the changing nature of heat stress now, and into the future, using historical data and climate change projections for the region using the temperature humidity index (THI). Projected temperature and relative humidity changes from two global climate models (GCMs), CSIRO MK3.5 and CCR-MIROC-H, have been used to calculate THI values for 2025 and 2050, and summarized as mean occurrence of, and mean length of consecutive high heat stress periods. The future climate scenarios explored show that by 2025 an additional 12-15 days (compared to 1971 to 2000 baseline data) of moderate to severe heat stress are likely across much of the study region. By 2050, larger increases in severity and occurrence of heat stress are likely (i.e. an additional 31-42 moderate to severe heat stress days compared with baseline data). This increasing trend will have a negative impact on milk production among dairy cattle in the region. The results from this study provide useful insights on the trends in THI in the region. Dairy farmers and the dairy industry could use these results to devise and prioritise adaptation options to deal with projected increases in heat stress frequency and severity.

Spatio-temporal modelling of heat stress and climate change implications for the Murray dairy region, Australia

NASA Astrophysics Data System (ADS)

Nidumolu, Uday; Crimp, Steven; Gobbett, David; Laing, Alison; Howden, Mark; Little, Stephen

2014-08-01

The Murray dairy region produces approximately 1.85 billion litres of milk each year, representing about 20 % of Australia's total annual milk production. An ongoing production challenge in this region is the management of the impacts of heat stress during spring and summer. An increase in the frequency and severity of extreme temperature events due to climate change may result in additional heat stress and production losses. This paper assesses the changing nature of heat stress now, and into the future, using historical data and climate change projections for the region using the temperature humidity index (THI). Projected temperature and relative humidity changes from two global climate models (GCMs), CSIRO MK3.5 and CCR-MIROC-H, have been used to calculate THI values for 2025 and 2050, and summarized as mean occurrence of, and mean length of consecutive high heat stress periods. The future climate scenarios explored show that by 2025 an additional 12-15 days (compared to 1971 to 2000 baseline data) of moderate to severe heat stress are likely across much of the study region. By 2050, larger increases in severity and occurrence of heat stress are likely (i.e. an additional 31-42 moderate to severe heat stress days compared with baseline data). This increasing trend will have a negative impact on milk production among dairy cattle in the region. The results from this study provide useful insights on the trends in THI in the region. Dairy farmers and the dairy industry could use these results to devise and prioritise adaptation options to deal with projected increases in heat stress frequency and severity.

Large bipolarons and oxide superconductivity

NASA Astrophysics Data System (ADS)

Emin, David

2017-02-01

Large-bipolaron superconductivity is plausible with carrier densities well below those of conventional metals. Bipolarons form when carriers self-trap in pairs. Coherently moving large-bipolarons require extremely large ratios of static to optical dielectric-constants. The mutual Coulomb repulsion of a planar large-bipolaron's paired carriers drives it to a four-lobed shape. A phonon-mediated attraction among large-bipolarons propels their condensation into a liquid. This liquid's excitations move slowly with a huge effective mass. Excitations' concomitant weak scattering by phonons produces a moderate low-temperature dc resistivity that increases linearly with rising temperature. With falling temperature an energy gap opens between large-bipolarons' excitations and those of their self-trapped electronic carriers.

Observations of the microclimate of a lake under cold air advective conditions

NASA Technical Reports Server (NTRS)

Bill, R. G., Jr.; Sutherland, R. A.; Bartholic, J. F.

1977-01-01

The moderating effects of Lake Apopka, Florida, on downwind surface temperatures were evaluated under cold air advective conditions. Point temperature measurements north and south of the lake and data obtained from the NOAA satellite and a thermal scanner flown at 1.6 km, indicate that, under conditions of moderate winds (approximately 4m/sec), surface temperatures directly downwind may be higher than surrounding surface temperatures by as much as 5 C. With surface wind speed less than 1m/sec, no substantial temperature effects were observed. Results of this study are being used in land use planning, lake level control and in agriculture for selecting planting sites.

Whole body cooling by immersion in water at moderate temperatures.

PubMed

Marino, F; Booth, J

1998-06-01

This study investigated the potential use of whole body cooling by water immersion for lowering body temperatures prior to endurance exercise. Rectal temperature (Tre), mean skin temperature (Tsk), oxygen consumption (VO2), and ventilation (VE) were measured in 7 male and 3 female subjects who were immersed in a water bath for up to 60 min. Initial water temperature was 28.8+/-1.5 degrees C and decreased to 23.8+/-1.1 degrees C by the end of immersion. Pre-immersion Tre of 37.34+/-0.36 degrees C was not altered by 60 min water immersion but decreased to 36.64+/-0.34 degrees C at 3 min post immersion (p < 0.01). Tsk decreased from 33.23+/-1.4 degrees C to 26.95+/-1.8 degrees C (p < 0.01) at the end of immersion. Reductions in Tre and Tsk resulted in reduced body heat content (Hc) of approximately 545 kJ (p < 0.01) at the end of immersion. VO2 and VE increased from pre-immersion values of 0.34+/-0.08 L x min(-1) and 6.2+/-1.4 L x min(-1) to 0.54+/-0.09 L x min(-) and 11.5+/-5.4 L x min(-1) at the end of immersion, respectively. Heart rate remained unchanged throughout immersion. These results indicate that whole body immersion in moderately cold water temperatures is an effective cooling maneuver for lowering body temperatures and body Hc in the absence of severe physiological responses generally associated with sudden cold stress.

The effect of core configuration on temperature coefficient of reactivity in IRR-1

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

Bettan, M.; Silverman, I.; Shapira, M.

1997-08-01

Experiments designed to measure the effect of coolant moderator temperature on core reactivity in an HEU swimming pool type reactor were performed. The moderator temperature coefficient of reactivity ({alpha}{sub {omega}}) was obtained and found to be different in two core loadings. The measured {alpha}{sub {omega}} of one core loading was {minus}13 pcm/{degrees}C at the temperature range of 23-30{degrees}C. This value of {alpha}{sub {omega}} is comparable to the data published by the IAEA. The {alpha}{sub {omega}} measured in the second core loading was found to be {minus}8 pcm/{degrees}C at the same temperature range. Another phenomenon considered in this study is coremore » behavior during reactivity insertion transient. The results were compared to a core simulation using the Dynamic Simulator for Nuclear Power Plants. It was found that in the second core loading factors other than the moderator temperature influence the core reactivity more than expected. These effects proved to be extremely dependent on core configuration and may in certain core loadings render the reactor`s reactivity coefficient undesirable.« less

Investigation of the MTC noise estimation with a coupled neutronic/thermal-hydraulic dedicated model - 'Closing the loop'

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

Demaziere, C.; Larsson, V.

2012-07-01

This paper investigates the reliability of different noise estimators aimed at determining the Moderator Temperature Coefficient (MTC) of reactivity in Pressurized Water Reactors. By monitoring the inherent fluctuations in the neutron flux and moderator temperature, an on-line monitoring of the MTC without perturbing reactor operation is possible. In order to get an accurate estimation of the MTC by noise analysis, the point-kinetic component of the neutron noise and the core-averaged moderator temperature noise have to be used. Because of the scarcity of the in-core instrumentation, the determination of these quantities is difficult, and several possibilities thus exist for estimating themore » MTC by noise analysis. Furthermore, the effect of feedback has to be negligible at the frequency chosen for estimating the MTC in order to get a proper determination of the MTC. By using an integrated neutronic/thermal- hydraulic model specifically developed for estimating the three-dimensional distributions of the fluctuations in neutron flux, moderator properties, and fuel temperature, different approaches for estimating the MTC by noise analysis can be tested individually. It is demonstrated that a reliable MTC estimation can only be provided if the core is equipped with a sufficient number of both neutron detectors and temperature sensors, i.e. if the core contain in-core detectors monitoring both the axial and radial distributions of the fluctuations in neutron flux and moderator temperature. It is further proven that the effect of feedback is negligible for frequencies higher than 0.1 Hz, and thus the MTC noise estimations have to be performed at higher frequencies. (authors)« less

Thermotolerance in preirradiated intestine and its influence on time-temperature relationships

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

Hume, S.P.; Marigold, J.C.; Manjil, L.G.

The crypt compartment of mouse jejunum showed a transient increase in thermal susceptibility approximately 10 days after moderate X-ray doses to the abdomen (9-10 Gy). The increase in response was manifest as an increase in slope of the crypt dose-response curve but was limited to temperatures below 43/sup 0/C. As a result, the 43/sup 0/C inflexion in the Arrhenius plot (the relationship between treatment time and temperature) for thermal sensitivity of crypts was eliminated in preirradiated tissue, and the curve became monophasic over the range 42.0-44.5/sup 0/C. At temperatures below 42/sup 0/C, the curve again deviated. At supranormal temperatures ofmore » 42/sup 0/C and below, the durations of hyperthermia needed for measurable effect were sufficient to allow thermotolerance to be expressed within the heating period. Neither the threshold heating times nor this thermotolerance were affected by prior irradiation. In the temperature range 42-43/sup 0/C, an earlier development of thermotolerance could be demonstrated in control tissue by challenging with an acute high-temperature heat treatment. This thermotolerance was eliminated in preirradiated tissue, resulting in the apparent increase in sensitivity. The findings support the view that the complex nature of the time-temperature relationship seen in normal tissue in vivo is a manifestation of the ability of the tissue to progressively acquire a thermotolerant state during treatment at temperatures below approximately 43/sup 0/C, so that the intrinsic sensitivity is modulated while being assessed.« less

Sexual and somatic development of wood frog tadpoles along a thermal gradient.

PubMed

Lambert, Max R; Smylie, Meredith S; Roman, Amber J; Freidenburg, L Kealoha; Skelly, David K

2018-02-01

All amphibian species are known to have genetic sex determination. However, a variety of environmental conditions can moderate sexual differentiation, in some cases leading to sex reversal and skewed sex ratios. While there has been a recent focus on chemically-induced sex reversal in amphibians, temperature can also influence sexual differentiation. Building upon a classic 1929 study by Emil Witschi, we assessed temperature-mediated sex reversal. Witschi found that the wood frog sex ratio is 100% male at a high temperature (32°C) compared to a 50:50 sex ratio at 20°C. This pattern is consistent with multiple models of environmentally mediated sexual differentiation in vertebrates. To better understand thermally mediated sex reversal, we raised wood frogs at temperature increments of ∼1°C between 19 and 34°C. Mirroring earlier findings, wood frog metamorph sex ratios are indistinguishable from 50:50 at the lowest temperature and entirely male at the highest temperatures. In between, sex ratios become increasingly male-dominated as temperatures increase, implying a steadily increasing tendency toward female-to-male sex reversal in warmer environments. There was no evidence of a threshold temperature effect on reversal patterns. We also show that, compared to males, females metamorphose larger and later in cooler conditions but earlier and smaller under warmer conditions. While the ecological relevance in this species is unknown, these results conform to the Charnov-Bull model of sex determination (in which female-to-male sex reversal can increase fitness to genetic females at higher temperatures), suggesting the system would reward further study. © 2018 Wiley Periodicals, Inc.

Dependence of phase configurations, microstructures and magnetic properties of iron-nickel (Fe-Ni) alloy nanoribbons on deoxidization temperature in hydrogen

NASA Astrophysics Data System (ADS)

Jing, Panpan; Liu, Mengting; Pu, Yongping; Cui, Yongfei; Wang, Zhuo; Wang, Jianbo; Liu, Qingfang

2016-11-01

Iron-nickel (Fe-Ni) alloy nanoribbons were reported for the first time by deoxidizing NiFe2O4 nanoribbons, which were synthesized through a handy route of electrospinning followed by air-annealing at 450 °C, in hydrogen (H2) at different temperatures. It was demonstrated that the phase configurations, microstructures and magnetic properties of the as-deoxidized samples closely depended upon the deoxidization temperature. The spinel NiFe2O4 ferrite of the precursor nanoribbons were firstly deoxidized into the body-centered cubic (bcc) Fe-Ni alloy and then transformed into the face-centered cubic (fcc) Fe-Ni alloy of the deoxidized samples with the temperature increasing. When the deoxidization temperature was in the range of 300 ~ 500 °C, although each sample possessed its respective morphology feature, all of them completely reserved the ribbon-like structures. When it was further increased to 600 °C, the nanoribbons were evolved completely into the fcc Fe-Ni alloy nanochains. Additionally, all samples exhibited typical ferromagnetism. The saturation magnetization (Ms) firstly increased, then decreased, and finally increased with increasing the deoxidization temperature, while the coercivity (Hc) decreased monotonously firstly and then basically stayed unchanged. The largest Ms (~145.7 emu·g-1) and the moderate Hc (~132 Oe) were obtained for the Fe-Ni alloy nanoribbons with a mixed configuration of bcc and fcc phases.

Dependence of phase configurations, microstructures and magnetic properties of iron-nickel (Fe-Ni) alloy nanoribbons on deoxidization temperature in hydrogen.

PubMed

Jing, Panpan; Liu, Mengting; Pu, Yongping; Cui, Yongfei; Wang, Zhuo; Wang, Jianbo; Liu, Qingfang

2016-11-23

Iron-nickel (Fe-Ni) alloy nanoribbons were reported for the first time by deoxidizing NiFe 2 O 4 nanoribbons, which were synthesized through a handy route of electrospinning followed by air-annealing at 450 °C, in hydrogen (H 2 ) at different temperatures. It was demonstrated that the phase configurations, microstructures and magnetic properties of the as-deoxidized samples closely depended upon the deoxidization temperature. The spinel NiFe 2 O 4 ferrite of the precursor nanoribbons were firstly deoxidized into the body-centered cubic (bcc) Fe-Ni alloy and then transformed into the face-centered cubic (fcc) Fe-Ni alloy of the deoxidized samples with the temperature increasing. When the deoxidization temperature was in the range of 300 ~ 500 °C, although each sample possessed its respective morphology feature, all of them completely reserved the ribbon-like structures. When it was further increased to 600 °C, the nanoribbons were evolved completely into the fcc Fe-Ni alloy nanochains. Additionally, all samples exhibited typical ferromagnetism. The saturation magnetization (M s ) firstly increased, then decreased, and finally increased with increasing the deoxidization temperature, while the coercivity (H c ) decreased monotonously firstly and then basically stayed unchanged. The largest M s (~145.7 emu·g -1 ) and the moderate H c (~132 Oe) were obtained for the Fe-Ni alloy nanoribbons with a mixed configuration of bcc and fcc phases.

Vertical lifting of ionization during geomagnetic storms from satellite measurements of ion composition

NASA Technical Reports Server (NTRS)

Goel, M. K.; Rao, B. C. N.; Chandra, S.; Maier, E. J.

1977-01-01

Magnetic-storm phenomena at low latitudes are discussed based on ion-composition /O(+), H(+), He(+)/ and electron- and ion-temperature measurements from the OGO-4 and Isis-2 satellites. For the moderately severe storms considered, the effects of changes in the neutral composition and in the neutral and plasma temperatures are discussed, and it is shown that these changes would not produce the observed O(+) increase during storms at low latitudes. It is suggested that the observed increase in O(+) in the topside region is a manifestation of the vertical lifting of ionization of the F-layer. The argument in favor of vertical lifting is further substantiated by the observed changes in the F-region critical frequency and the height parameters.

Synergistic chemotherapy by combined moderate hyperthermia and photochemical internalization.

PubMed

Christie, Catherine; Molina, Stephanie; Gonzales, Jonathan; Berg, Kristian; Nair, Rohit Kumar; Huynh, Khoi; Madsen, Steen J; Hirschberg, Henry

2016-04-01

Combination therapies of photochemical internalization (PCI) and moderate hyperthermia (MHT) were investigated in an in vitro system consisting of human and rat glioma spheroids. PCI using the amphiphilic photosensitizer, AlPcS2a and two anti cancer agents BLM or 5-FU were used. Spheroids were irradiated with λ = 670 nm laser light in an incubator at temperatures ranging from 37 to 44°C. For each temperature investigated, spheroids were divided into 4 groups: control, drug-only, photodynamic therapy (PDT), and PCI. PDT and PCI spheroids were exposed to radiant exposures ranging from 0.3 to 2.5 J cm(-2) using an irradiance of 5 mW cm(-2). Toxicity was evaluated from spheroid growth kinetics. The combination of PCI and MHT resulted in significant increases in BLM efficacy at 44°C for both cell line derived spheroids compared to controls at 37°C over the range of radiant exposures examined. 5-FU PCI was ineffective for the human cell line at both 37 and 44°C.

Who's hot, who's not? Effects of concentrating solar power heliostats on soil temperature at Ivanpah Solar Electric Generating System, Mojave Desert, USA

NASA Astrophysics Data System (ADS)

Grodsky, S.; Hernandez, R. R.

2017-12-01

Solar energy development may function as a contemporary, anthropogenic driver of disturbance when sited in natural ecosystems. Orientation and density of solar modules, including heliostats at concentrating solar power (CSP) facilities, may affect soils via shading and altered surface-water flow. Meanwhile, soil attributes like temperature and moisture may affect nutrient cycling, plant germination and growth, and soil biota. We tested effects of CSP heliostats on soil temperature at Ivanpah Solar Electric Generating System (ISEGS) in the Mojave Desert, USA. We implemented experimental treatments based on preconstruction rare plant [e.g., Mojave milkweed (Asclepias nyctaginifolia)] protection areas (hereafter "halos"), site preparation activities, and heliostat density throughout three, replicated CSP blocks (i.e., tower and associated heliostats), including: (1) No Halos (Bladed) - high site preparation intensity, high heliostat density immediately surrounding towers; (2) No Halos (Mowed) - moderate site preparation intensity, moderate to low heliostat density as distance increases from towers; and (3) Halos - no site preparation, no heliostats. We also established control sites within 1,600 km of ISEGS in undisturbed desert. We observed significant differences in soil temperature across treatments. We recorded significantly lower soil temperatures in the No Halos (Bladed) treatments (26.7°C) and No Halos (Mowed) treatments (29.9°C) than in the Halos treatments (32.9°C) and controls (32.1°C). We also determined that soil temperatures in the Halos treatments and controls did not significantly differ. Our results indicated that shading from high-density heliostat configuration significantly reduced soil temperature relative to low-density heliostat configuration and areas without CSP. Shading from heliostats and consequential fluctuation in soil temperatures may affect local-scale distribution of flora and fauna, leading to altered "bottom-up" ecological interactions at ISEGS.

Cytotoxicity assay of biosynthesis gold nanoparticles mediated by walnut (Juglans regia) green husk extract

NASA Astrophysics Data System (ADS)

Izadiyan, Zahra; Shameli, Kamyar; Hara, Hirofumi; Mohd Taib, Siti Husnaa

2018-01-01

The unique properties of gold nanoparticles (Au-NPs) produce in plant extract make them attractive for use in medical and industrial applications, it is necessary to develop environmentally friendly methods for their synthesis. This can be accomplished by replacing the traditional chemical compounds for the reduction of the gold ions to Au-NPs during synthesis with natural plant extracts or with plasmas atmospheric pressure. Here, the biosynthesis of Au-NPs using the Juglans regia (J. regia) green husk extract was investigated as the reducing and stabilizing agent. The formation of Au-NPs was initially monitored by visual observation and then characterized with the help of various characterization techniques. UV-vis spectroscopy results showed that Au-NPs synthesized using moderate temperature have a blue shifting, good distribution and smaller size compare with Au-NPs fabricated in room temperature. X-ray diffraction (XRD) results revealed the distinctive formation of the crystalline structure of Au-NPs with a spherical shape. According to transmission electron microscopy (TEM), the mean diameter and standard deviation of Au-NPs at room and moderate temperatures were 19.19 ± 4.7 and 14.32 ± 3.24 nm, respectively. The result of Field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) are in good agreement with each other and confirm that by using the moderate temperature compare to the room temperature the yield of reaction increased. Based on the zeta potential result, Au-NPs has sufficient value for the stability of the solution. According to FTIR spectrum, the J. regia would be coated on the gold ions surface in a successful manner. The non-toxic effect of Au-NPs concentration below 250 μg/ml was observed in the studies of in vitro cytotoxicity on normal and cancerous cell lines, respectively. The dose-dependent toxicity made it a suitable candidate for various medical applications.

Moderate temperature-dependent surface and volume resistivity and low-frequency dielectric constant measurements of pure and multi-walled carbon nanotube (MWCNT) doped polyvinyl alcohol thin films

NASA Astrophysics Data System (ADS)

Edwards, Matthew; Guggilla, Padmaja; Reedy, Angela; Ijaz, Quratulann; Janen, Afef; Uba, Samuel; Curley, Michael

2017-08-01

Previously, we have reported measurements of temperature-dependent surface resistivity of pure and multi-walled carbon nanotube (MWNCT) doped amorphous Polyvinyl Alcohol (PVA) thin films. In the temperature range from 22 °C to 40 °C with humidity-controlled environment, we found the surface resistivity to decrease initially, but to rise steadily as the temperature continued to increase. Moreover, electric surface current density (Js) was measured on the surface of pure and MWCNT doped PVA thin films. In this regard, the surface current density and electric field relationship follow Ohm's law at low electric fields. Unlike Ohmic conduction in metals where free electrons exist, selected captive electrons are freed or provided from impurities and dopants to become conduction electrons from increased thermal vibration of constituent atoms in amorphous thin films. Additionally, a mechanism exists that seemingly decreases the surface resistivity at higher temperatures, suggesting a blocking effect for conducting electrons. Volume resistivity measurements also follow Ohm's law at low voltages (low electric fields), and they continue to decrease as temperatures increase in this temperature range, differing from surface resistivity behavior. Moreover, we report measurements of dielectric constant and dielectric loss as a function of temperature and frequency. Both the dielectric constant and dielectric loss were observed to be highest for MWCNT doped PVA compared to pure PVA and commercial paper, and with frequency and temperature for all samples.

Association of temperature and historical dynamics of malaria in the Republic of Korea, including reemergence in 1993.

PubMed

Linthicum, Kenneth J; Anyamba, Assaf; Killenbeck, Bradley; Lee, Won-Ja; Lee, Hee Choon S; Klein, Terry A; Kim, Heung-Chul; Pavlin, Julie A; Britch, Seth C; Small, Jennifer; Tucker, Compton J; Gaydos, Joel C

2014-07-01

Plasmodium vivax malaria reemerged in the Republic of Korea in 1993 after it had been declared malaria free in 1979. Malaria rapidly increased and peaked in 2000 with 4,142 cases with lower but variable numbers of cases reported through 2011. We examined the association of regional climate trends over the Korean Peninsula relative to malaria cases in U.S. military and Republic of Korea soldiers, veterans, and civilians from 1950 to 2011. Temperatures and anomaly trends in air temperature associated with satellite remotely sensed outgoing long-wave radiation were used to observe temporal changes. These changes, particularly increasing air temperatures, in combination with moderate rains throughout the malaria season, and distribution of malaria vectors, likely supported the 1993 reemergence and peaks in malaria incidence that occurred through 2011 by accelerating the rate of parasite development in mosquitoes and increased numbers as a result of an expansion of larval habitat, thereby increasing the vectorial capacity of Anopheles vectors. High malaria rates associated with a favorable climate were similarly observed during the Korean War. These findings support the need for increased investigations into malaria predictive models using climate-related variables. Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.

Observations of the convective plume of a lake under cold-air advective conditions

NASA Technical Reports Server (NTRS)

Bill, R. G., Jr.; Sutherland, R. A.; Bartholic, J. F.; Chen, E.

1978-01-01

Moderating effects of Lake Apopka, Florida, on downwind surface temperatures were evaluated under cold-air advective conditions. Point temperature measurements north and south of the lake and data obtained from a thermal scanner flown at 1.6 km indicate that surface temperatures directly downwind may be higher than surrounding surface temperatures by as much as 5 C under conditions of moderate winds (about 4 m/s). No substantial temperature effects were observed with surface wind speed less than 1 m/s. Fluxes of sensible and latent heat from Lake Apopka were calculated from measurements of lake temperature, net radiation, relative humidity, and air temperature above the lake. Bulk transfer coefficients and the Bowen ratio were calculated and found to be in agreement with reported data for nonadvective conditions.

Heat Wave and Mortality: A Multicountry, Multicommunity Study

PubMed Central

Gasparrini, Antonio; Armstrong, Ben G.; Tawatsupa, Benjawan; Tobias, Aurelio; Lavigne, Eric; Coelho, Micheline de Sousa Zanotti Stagliorio; Pan, Xiaochuan; Kim, Ho; Hashizume, Masahiro; Honda, Yasushi; Guo, Yue-Liang Leon; Wu, Chang-Fu; Zanobetti, Antonella; Schwartz, Joel D.; Bell, Michelle L.; Scortichini, Matteo; Michelozzi, Paola; Punnasiri, Kornwipa; Li, Shanshan; Tian, Linwei; Garcia, Samuel David Osorio; Seposo, Xerxes; Overcenco, Ala; Zeka, Ariana; Goodman, Patrick; Dang, Tran Ngoc; Dung, Do Van; Mayvaneh, Fatemeh; Saldiva, Paulo Hilario Nascimento; Williams, Gail; Tong, Shilu

2017-01-01

Background: Few studies have examined variation in the associations between heat waves and mortality in an international context. Objectives: We aimed to systematically examine the impacts of heat waves on mortality with lag effects internationally. Methods: We collected daily data of temperature and mortality from 400 communities in 18 countries/regions and defined 12 types of heat waves by combining community-specific daily mean temperature ≥90th, 92.5th, 95th, and 97.5th percentiles of temperature with duration ≥2, 3, and 4 d. We used time-series analyses to estimate the community-specific heat wave–mortality relation over lags of 0–10 d. Then, we applied meta-analysis to pool heat wave effects at the country level for cumulative and lag effects for each type of heat wave definition. Results: Heat waves of all definitions had significant cumulative associations with mortality in all countries, but varied by community. The higher the temperature threshold used to define heat waves, the higher heat wave associations on mortality. However, heat wave duration did not modify the impacts. The association between heat waves and mortality appeared acutely and lasted for 3 and 4 d. Heat waves had higher associations with mortality in moderate cold and moderate hot areas than cold and hot areas. There were no added effects of heat waves on mortality in all countries/regions, except for Brazil, Moldova, and Taiwan. Heat waves defined by daily mean and maximum temperatures produced similar heat wave–mortality associations, but not daily minimum temperature. Conclusions: Results indicate that high temperatures create a substantial health burden, and effects of high temperatures over consecutive days are similar to what would be experienced if high temperature days occurred independently. People living in moderate cold and moderate hot areas are more sensitive to heat waves than those living in cold and hot areas. Daily mean and maximum temperatures had similar ability to define heat waves rather than minimum temperature. https://doi.org/10.1289/EHP1026 PMID:28886602

Preliminary Flight Deck Observations During Flight in High Ice Water Content Conditions

NASA Technical Reports Server (NTRS)

Ratvasky, Thomas; Duchanoy, Dominque; Bourdinot, Jean-Francois; Harrah, Steven; Strapp, Walter; Schwarzenboeck, Alfons; Dezitter, Fabien; Grandin, Alice

2015-01-01

In 2006, Mason et al. identified common observations that occurred in engine power-loss events attributed to flight in high concentrations of ice crystals. Observations included light to moderate turbulence, precipitation on the windscreen (often reported as rain), aircraft total temperature anomalies, lack of significant airframe icing, and no flight radar echoes at the location and altitude of the engine event. Since 2006, Mason et al. and others have collected information from pilots who experienced engine power-loss events via interviews and questionnaires to substantiate earlier observations and support event analyses. In 2011, Mason and Grzych reported that vertical acceleration data showed increases in turbulence prior to engine events, although the turbulence was usually light to moderate and not unique to high ice water content (HIWC) clouds. Mason concluded that the observation of rain on the windscreen was due to melting of ice high concentrations of ice crystals on the windscreen, coalescing into drops. Mason also reported that these pilot observations of rain on the windscreen were varied. Many pilots indicated no rain was observed, while others observed moderate rain with unique impact sounds. Mason concluded that the variation in the reports may be due to variation in the ice concentration, particle size, and temperature.

Changes in the convective population and thermodynamic environments in convection-permitting regional climate simulations over the United States

NASA Astrophysics Data System (ADS)

Rasmussen, K. L.; Prein, A. F.; Rasmussen, R. M.; Ikeda, K.; Liu, C.

2017-11-01

Novel high-resolution convection-permitting regional climate simulations over the US employing the pseudo-global warming approach are used to investigate changes in the convective population and thermodynamic environments in a future climate. Two continuous 13-year simulations were conducted using (1) ERA-Interim reanalysis and (2) ERA-Interim reanalysis plus a climate perturbation for the RCP8.5 scenario. The simulations adequately reproduce the observed precipitation diurnal cycle, indicating that they capture organized and propagating convection that most climate models cannot adequately represent. This study shows that weak to moderate convection will decrease and strong convection will increase in frequency in a future climate. Analysis of the thermodynamic environments supporting convection shows that both convective available potential energy (CAPE) and convective inhibition (CIN) increase downstream of the Rockies in a future climate. Previous studies suggest that CAPE will increase in a warming climate, however a corresponding increase in CIN acts as a balancing force to shift the convective population by suppressing weak to moderate convection and provides an environment where CAPE can build to extreme levels that may result in more frequent severe convection. An idealized investigation of fundamental changes in the thermodynamic environment was conducted by shifting a standard atmospheric profile by ± 5 °C. When temperature is increased, both CAPE and CIN increase in magnitude, while the opposite is true for decreased temperatures. Thus, even in the absence of synoptic and mesoscale variations, a warmer climate will provide more CAPE and CIN that will shift the convective population, likely impacting water and energy budgets on Earth.

Structural and magnetic properties of cobalt ferrite nanoparticles synthesized by co-precipitation at increasing temperatures

NASA Astrophysics Data System (ADS)

Stein, C. R.; Bezerra, M. T. S.; Holanda, G. H. A.; André-Filho, J.; Morais, P. C.

2018-05-01

This study reports on the synthesis and characterization of cobalt ferrite (CoFe2O4) nanoparticles (NPs) synthesized by chemical co-precipitation in alkaline medium at increasing temperatures in the range of 27 °C to 100 °C. High-quality samples in the size range of 5 to 10 nm were produced using very low stirring speed (250 rpm) and moderate alkaline aqueous solution concentration (4.8 mol/L). Three samples were synthesized and characterized by x-ray diffraction (XRD) and room-temperature (RT) magnetization measurements. All samples present superparamagnetic (SPM) behavior at RT and Rietveld refinements confirm the inverse cubic spinel structure (space group Fd-3m (227)) with minor detectable impurity phase. As the synthesis temperature increases, structural parameters such as lattice constant and grain size change monotonically from 8.385 to 8.383 Å and from 5.8 to 7.4 nm, respectively. Likewise, as the synthesis temperature increases the NPs' magnetic moment and saturation magnetization increases monotonically from 2.6 ×103 to 16×103 μB and from 37 to 66 emu/g, respectively. The RT magnetization (M) versus applied field (H) curves were analyzed by the first-order Langevin function averaged out by a lognormal distribution function of magnetic moments. The excellent curve-fitting of the M versus H data is credited to a reduced particle-particle interaction due to both the SPM behavior and the existence of a surface amorphous shell layer (dead layer), the latter reducing systematically as the synthesis temperature increases.

Precise ablation of dental hard tissues with ultra-short pulsed lasers. Preliminary exploratory investigation on adequate laser parameters.

PubMed

Bello-Silva, Marina Stella; Wehner, Martin; Eduardo, Carlos de Paula; Lampert, Friedrich; Poprawe, Reinhart; Hermans, Martin; Esteves-Oliveira, Marcella

2013-01-01

This study aimed to evaluate the possibility of introducing ultra-short pulsed lasers (USPL) in restorative dentistry by maintaining the well-known benefits of lasers for caries removal, but also overcoming disadvantages, such as thermal damage of irradiated substrate. USPL ablation of dental hard tissues was investigated in two phases. Phase 1--different wavelengths (355, 532, 1,045, and 1,064 nm), pulse durations (picoseconds and femtoseconds) and irradiation parameters (scanning speed, output power, and pulse repetition rate) were assessed for enamel and dentin. Ablation rate was determined, and the temperature increase measured in real time. Phase 2--the most favorable laser parameters were evaluated to correlate temperature increase to ablation rate and ablation efficiency. The influence of cooling methods (air, air-water spray) on ablation process was further analyzed. All parameters tested provided precise and selective tissue ablation. For all lasers, faster scanning speeds resulted in better interaction and reduced temperature increase. The most adequate results were observed for the 1064-nm ps-laser and the 1045-nm fs-laser. Forced cooling caused moderate changes in temperature increase, but reduced ablation, being considered unnecessary during irradiation with USPL. For dentin, the correlation between temperature increase and ablation efficiency was satisfactory for both pulse durations, while for enamel, the best correlation was observed for fs-laser, independently of the power used. USPL may be suitable for cavity preparation in dentin and enamel, since effective ablation and low temperature increase were observed. If adequate laser parameters are selected, this technique seems to be promising for promoting the laser-assisted, minimally invasive approach.

Tribological Performance of PM300 Solid Lubricant Bushings for High Temperature Applications

NASA Technical Reports Server (NTRS)

Striebing, Donald R.; Stanford, Malcolm K.; DellaCorte, Christopher; Rossi, Anne M.

2007-01-01

PM300 is a high temperature solid lubricant material produced through conventional powder metallurgy processing. PM300 is a combination of metal binder (NiCr), hardener (Cr2O3) and lubricant (Ag and BaF2/CaF2) phases and is in commercial use in high temperature furnace conveyors. In this paper, the tribological characteristics of PM300 are evaluated using a newly developed bushing test rig in which PM300 bushings are loaded against rotating steel shafts at temperatures from 25 to 650 C. The data shows that friction and wear are low to moderate and that the lubrication performance (friction) improves with increasing temperature. Several alternative PM300 compositions are evaluated which do not contain silver and are targeted at aircraft gas turbine applications in which environmental compatibility of silver is a concern. It is expected that the data resulting from this research will further the commercialization of this technology.

Temperature sensitivity of organic-matter decay in tidal marshes

USGS Publications Warehouse

Kirwan, Matthew L.; Guntenspergen, Glenn R.; Langley, J.A.

2014-01-01

Approximately half of marine carbon sequestration takes place in coastal wetlands, including tidal marshes, where organic matter contributes to soil elevation and ecosystem persistence in the face of sea-level rise. The long-term viability of marshes and their carbon pools depends, in part, on how the balance between productivity and decay responds to climate change. Here, we report the sensitivity of labile soil organic-matter decay in tidal marshes to seasonal and latitudinal variations in temperature measured over a 3-year period. We find a moderate increase in decay rate at warmer temperatures (3-6% per °C, Q10 = 1.3-1.5). Despite the profound differences between microbial metabolism in wetlands and uplands, our results indicate a strong conservation of temperature sensitivity. Moreover, simple comparisons with organic-matter production suggest that elevated atmospheric CO2 and warmer temperatures will accelerate carbon accumulation in marsh soils, and potentially enhance their ability to survive sea-level rise.

18F-FDG uptake in the colon is modulated by metformin but not associated with core body temperature and energy expenditure

PubMed Central

Bahler, Lonneke; Holleman, Frits; Chan, Man-Wai; Booij, Jan; Hoekstra, Joost B.; Verberne, Hein J.

2017-01-01

Purpose Physiological colonic 18F-fluorodeoxyglucose (18F-FDG) uptake is a frequent finding on 18F-FDG positron emission tomography computed tomography (PET-CT). Interestingly, metformin, a glucose lowering drug associated with moderate weight loss, is also associated with an increased colonic 18F-FDG uptake. Consequently, increased colonic glucose use might partly explain the weight losing effect of metformin when this results in an increased energy expenditure and/or core body temperature. Therefore, we aimed to determine whether metformin modifies the metabolic activity of the colon by increasing glucose uptake. Methods In this open label, non-randomized, prospective mechanistic study, we included eight lean and eight overweight males. We measured colonic 18F-FDG uptake on PET-CT, energy expenditure and core body temperature before and after the use of metformin. The maximal colonic 18F-FDG uptake was measured in 5 separate segments (caecum, colon ascendens,—transversum,—descendens and sigmoid). Results The maximal colonic 18F-FDG uptake increased significantly in all separate segments after the use of metformin. There was no significant difference in energy expenditure or core body temperature after the use of metformin. There was no correlation between maximal colonic 18F-FDG uptake and energy expenditure or core body temperature. Conclusion Metformin significantly increases colonic 18F-FDG uptake, but this increased uptake is not associated with an increase in energy expenditure or core body temperature. Although the colon might be an important site of the glucose plasma lowering actions of metformin, this mechanism of action does not explain directly any associated weight loss. PMID:28464031

Mortality related to cold and heat. What do we learn from dairy cattle?

PubMed Central

Cox, Bianca; Gasparrini, Antonio; Catry, Boudewijn; Delcloo, Andy; Bijnens, Esmée; Vangronsveld, Jaco; Nawrot, Tim S.

2016-01-01

Extreme temperatures are associated with increased mortality among humans. Because similar epidemiologic studies in animals may add to the existing evidence, we investigated the association between ambient temperature and the risk of mortality among dairy cattle. We used data on 87,108 dairy cow deaths in Belgium from 2006 to 2009, and we combined a case-crossover design with distributed lag non-linear models. Province-specific results were combined in a multivariate meta-analysis. Relative to the estimated minimum mortality temperature of 15.4 °C (75th percentile), the pooled cumulative relative risks over lag 0–25 days were 1.26 (95% CI: 1.11, 1.42) for extreme cold (1st percentile, −3.5 °C), 1.35 (95% CI: 1.19, 1.54) for moderate cold (5th percentile, −0.3 °C), 1.09 (95% CI: 1.02, 1.17) for moderate heat (95th percentile, 19.7 °C), and 1.26 (95% CI: 1.08; 1.48) for extreme heat (99th percentile, 22.6 °C). The temporal pattern of the temperature-mortality association was similar to that observed in humans, i.e. acute effects of heat and delayed and prolonged effects of cold. Seasonal analyses suggested that most of the temperature-related mortality, including cold effects, occurred in the warm season. Our study reinforces the evidence on the plausibility of causal effects in humans. PMID:27236362

Hydrological effects of cropland and climatic changes in arid and semi-arid river basins: A case study from the Yellow River basin, China

NASA Astrophysics Data System (ADS)

Li, Huazhen; Zhang, Qiang; Singh, Vijay P.; Shi, Peijun; Sun, Peng

2017-06-01

The Yellow River basin is a typical semi-arid river basin in northern China. Serious water shortages have negative impacts on regional socioeconomic development. Recent years have witnessed changes in streamflow processes due to increasing human activities, such as agricultural activities and construction of dams and water reservoirs, and climatic changes, e.g. precipitation and temperature. This study attempts to investigate factors potentially driving changes in different streamflow components defined by different quantiles. The data used were daily streamflow data for the 1959-2005 period from 5 hydrological stations, daily precipitation and temperature data from 77 meteorological stations and data pertaining to cropland and large reservoirs. Results indicate a general decrease in streamflow across the Yellow River basin. Moreover significant decreasing streamflow has been observed in the middle and lower Yellow River basin with change points during the mid-1980s till the mid-1990s. The changes of cropland affect the streamflow components and also the cumulative effects on streamflow variations. Recent years have witnessed moderate cropland variations which result in moderate streamflow changes. Further, precipitation also plays a critical role in changes of streamflow components and human activities, i.e. cropland changes, temperature changes and building of water reservoirs, tend to have increasing impacts on hydrological processes across the Yellow River basin. This study provides a theoretical framework for the study of the hydrological effects of human activities and climatic changes on basins over the globe.

Tuning of thermally induced sol-to-gel transitions of moderately concentrated aqueous solutions of doubly thermosensitive hydrophilic diblock copolymers poly(methoxytri(ethylene glycol) acrylate)-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid).

PubMed

Jin, Naixiong; Zhang, Hao; Jin, Shi; Dadmun, Mark D; Zhao, Bin

2012-03-15

We report in this article a method to tune the sol-to-gel transitions of moderately concentrated aqueous solutions of doubly thermosensitive hydrophilic diblock copolymers that consist of two blocks exhibiting distinct lower critical solution temperatures (LCSTs) in water. A small amount of weak acid groups is statistically incorporated into the lower LCST block so that its LCST can be tuned by varying solution pH. Well-defined diblock copolymers, poly(methoxytri(ethylene glycol) acrylate)-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid) (PTEGMA-b-P(DEGEA-co-AA)), were prepared by reversible addition-fragmentation chain transfer polymerization and postpolymerization modification. PTEGMA and PDEGEA are thermosensitive water-soluble polymers with LCSTs of 58 and 9 °C, respectively, in water. A 25 wt % aqueous solution of PTEGMA-b-P(DEGEA-co-AA) with a molar ratio of DEGEA to AA units of 100:5.2 at pH = 3.24 underwent multiple phase transitions upon heating, from a clear, free-flowing liquid (<15 °C) to a clear, free-standing gel (15-46 °C) to a clear, free-flowing hot liquid (47-56 °C), and a cloudy mixture (≥57 °C). With the increase of pH, the sol-to-gel transition temperature (T(sol-gel)) shifted to higher values, while the gel-to-sol transition (T(gel-sol)) and the clouding temperature (T(clouding)) of the sample remained essentially the same. These transitions and the tunability of T(sol-gel) originated from the thermosensitive properties of two blocks of the diblock copolymer and the pH dependence of the LCST of P(DEGEA-co-AA), which were confirmed by dynamic light scattering and differential scanning calorimetry studies. Using the vial inversion test method, we mapped out the C-shaped sol-gel phase diagrams of the diblock copolymer in aqueous buffers in the moderate concentration range at three different pH values (3.24, 5.58, and 5.82, all measured at ~0 °C). While the upper temperature boundaries overlapped, the lower temperature boundary shifted upward and the critical gelation concentration increased with the increase of pH. The AA content in PTEGMA-b-P(DEGEA-co-AA) was found to have a significant effect on the pH dependence of T(sol-gel). For PTEGMA-b-P(DEGEA-co-AA) with a molar ratio of DEGEA to AA units of 100:10, the T(sol-gel) of its 25 wt % aqueous solution increased faster with the increase of pH than that of PTEGMA-b-P(DEGEA-co-AA) with a DEGEA-to-AA molar ratio of 100:5.2. © 2012 American Chemical Society

The current-induced heat generation in a spin-flip quantum dot sandwiched between a ferromagnetic and a superconducting electrode

NASA Astrophysics Data System (ADS)

Jiang, Feng; Yan, Yonghong; Wang, Shikuan; Yan, Yijing

2017-12-01

Using non-equilibrium Green's functions' theory based on extended Nambu representation and small polaron transformation, we studied the current-induced heat generation in a spin-flip quantum dot sandwiched between a ferromagnetic and a superconducting electrode. We focused on moderate dot-leads coupling and relative small phonon energy, and derived the detailed expression of heat generation. The numerical results show (i) the heat generation decreases with polarization degree increasing, (ii) the intradot spin-flip can have a great effect on the heat generation at both zero temperature and finite temperature and (iii) at finite temperature an optimal workspace of keeping spin current and tuning heat generation by modulating the spin-flip intensity can be found.

Differential effects of dopamine and opioid receptor blockade on motivated Coca-Cola drinking behavior and associated changes in brain, skin and muscle temperatures

PubMed Central

Kiyatkin, Eugene A.

2010-01-01

Although pharmacological blockade of both dopamine (DA) and opiate receptors has an inhibiting effect on appetitive motivated behaviors, it is still unclear which physiological mechanisms affected by these treatments underlie the behavioral deficit. To clarify this issue, we examined how pharmacological blockade of either DA (SCH23390 + eticlopride at 0.2 mg/kg each) or opioid receptors (naloxone 1 mg/kg) affects motor activity and temperature fluctuations in the nucleus acumens (NAcc), temporal muscle, and facial skin associated with motivated Coca-Cola drinking behavior in rats. In drug-free conditions, presentation of a cup containing 5 ml of Coca-Cola induced locomotor activation and rapid NAcc temperature increases, which both transiently decreased during drinking, and phasically increased again after the cup was emptied. Muscle temperatures followed this pattern, but increases were weaker and more delayed than those in the NAcc. Skin temperature rapidly dropped after cup presentation, remained at low levels during consumption, and slowly restored during post-consumption behavioral activation. By itself, DA receptor blockade induced robust decrease in spontaneous locomotion, moderate increases in brain and muscle temperatures, and a relative increase in skin temperatures, suggesting metabolic activation coupled with adynamia. Following this treatment (∼180 min), motor activation to cup presentation and Coca-Cola consumption were absent, but rats showed NAcc and muscle temperature increases following cup presentation comparable to control. Therefore, DA receptor blockade does not affect significantly central and peripheral autonomic responses to appetitive stimuli, but eliminates their behavior-activating effects, thus disrupting appetitive behavior and blocking consumption. Naloxone alone slightly decreased brain and muscle temperatures and increased skin temperatures, pointing at the enhanced heat loss and possible minor inhibition of basal metabolic activity. This treatment (∼60 min) had minimal effects on the latencies of drinking, but increased its total duration, with licking interrupted by pauses and retreats. This behavioral attenuation was coupled with weaker than in control locomotor activation and diminished temperature fluctuations in each recording location. Therefore, attenuation of normal behavioral and physiological responses to appetitive stimuli appears to underlie modest inhibiting effects of opiate receptor blockade on motivated behavior and consumption. PMID:20167257

Reliable, Low-Cost, Low-Weight, Non-Hermetic Coating for MCM Applications

NASA Technical Reports Server (NTRS)

Jones, Eric W.; Licari, James J.

2000-01-01

Through an Air Force Research Laboratory sponsored STM program, reliable, low-cost, low-weight, non-hermetic coatings for multi-chip-module(MCK applications were developed. Using the combination of Sandia Laboratory ATC-01 test chips, AvanTeco's moisture sensor chips(MSC's), and silicon slices, we have shown that organic and organic/inorganic overcoatings are reliable and practical non-hermetic moisture and oxidation barriers. The use of the MSC and unpassivated ATC-01 test chips provided rapid test results and comparison of moisture barrier quality of the overcoatings. The organic coatings studied were Parylene and Cyclotene. The inorganic coatings were Al2O3 and SiO2. The choice of coating(s) is dependent on the environment that the device(s) will be exposed to. We have defined four(4) classes of environments: Class I(moderate temperature/moderate humidity). Class H(high temperature/moderate humidity). Class III(moderate temperature/high humidity). Class IV(high temperature/high humidity). By subjecting the components to adhesion, FTIR, temperature-humidity(TH), pressure cooker(PCT), and electrical tests, we have determined that it is possible to reduce failures 50-70% for organic/inorganic coated components compared to organic coated components. All materials and equipment used are readily available commercially or are standard in most semiconductor fabrication lines. It is estimated that production cost for the developed technology would range from $1-10/module, compared to $20-200 for hermetically sealed packages.

Large electrostrictive effect in (Ba1-xGd2x/3)Zr0.3Ti0.7O3 relaxor towards moderate field actuator and energy storage applications

NASA Astrophysics Data System (ADS)

Ghosh, S. K.; Saha, Sujoy; Sinha, T. P.; Rout, S. K.

2016-11-01

The need of lead-free high performance ceramics with large electrostrictive effect, minimum hysteresis loss and energy storage ability at room temperature has become indispensable. At room temperature one of the key challenges in ceramic materials is to enhance the electrostrictive and energy storage properties simultaneously. In this regards, lead-free gadolinium modified barium zirconate titanate (Ba1-xGd2x/3)(Zr0.3Ti0.7)O3 (x = 0.02, 0.04, 0.06, 0.08, 0.10) ceramic was experimentally investigated to gain the competent electromechanical parameters near room temperature. Dielectric measurements exhibit a diffuse type of phase transition of relaxor phenomena and slim hysteresis loop with low remnant polarization and low hysteresis loss were observed. A moderate electric field of 30 kV/cm, recoverable energy and storage efficiency increases with Gd content. Strain-electric field hysteresis curves such as S-E, S-E2, and S-P2 profiles indicate improved electrostrictive characteristic of the ceramics. Results show that a maximum strain S ˜ 0.083% with large electrostrictive coefficient Q11 ˜ 0.054 m4/C2 and M11 ˜ 0.142 × 10-16 m2/V2 were obtained for x = 0.02 based BGdZT composition near relaxor-paraelectric phase boundary. The behavior of electrostrictive effect and energy storage efficiency suggested new possibilities of high precision lead-free ceramic actuator in a moderate field.

Mechanism for the occurrence of paramagnetic planes within magnetically ordered cerium systems

NASA Astrophysics Data System (ADS)

Kioussis, Nicholas; Cooper, Bernard R.; Banerjea, Amitava

1988-11-01

Hybridization of moderately delocalized f electrons with band electrons gives rise to a highly anisotropic two-ion interaction. Previously it has been shown that such an interaction explains the experimentally observed unusual magnetic behavior of CeBi, yielding a phase transition from a higher-temperature type-I (↑↓) to a lower-temperature type-IA (↑↑↓↓) antiferromagnetic structure. If the hybridization-mediated interaction is the key to understanding the magnetic behavior of such moderately delocalized f-electron systems, we should expect to be able to understand on this basis the even more unusual magnetic behavior of CeSb. In CeSb, there is a sequence of magnetic structures in which the higher-temperature structures involve a periodic stacking of paramagnetic \\{001\\} planes alternating with magnetically ordered \\{001\\} planes of [001]-moment alignment. In this paper we show that such a coexistence of paramagnetic and magnetically ordered Ce3+ sites can be understood on the basis of the hybridization-mediated interionic interaction when there are cubic crystal-field (CF) interactions of comparable strength. The tendency to form paramagnetic planes is found to increase with increasing CF strength (Γ7 ground state); and the stability of the up-down paramagnetic plane arrangement at high temperatures is shown to arise from the reconciliation of the magnetic ordering with the CF interactions. We also find that for a certain range of parameters a different novel situation occurs, with a fully nonmagnetic (singlet) ground state for the Ce3+ ion. This singlet state is not Kondo-like, and occurs in such a way that the system would be expected to fluctuate between two differently polarized states, one of which is the singlet state.

Experimental study on the responsivity enhancement of Mn1.56Co0.96Ni0.48O4 detector under moderate bias field

NASA Astrophysics Data System (ADS)

Zhou, Wei; Hou, Yun; Gao, Yan Qing; Zhang, Leibo; Huang, Zhi Ming

2011-08-01

As a typical thermal sensitive material, Mn1.56Co0.96Ni0.48O4 (MCN) has achieved widely applications in uncooled bolometer. In this paper, we report that a large increase in electrical conductivity of MCN is obtained with moderate electric-field strengths (E~103V/cm) applied at room temperature (about 300K). Great enhancement in the responsivity is observed when operating with a proper electric bias field, which corresponds to a threshold voltage VTh. MCN bulk materials are prepared by using the sintering method. Micro MCN detector is fabricated by scribing the bulk material into pieces sized 200×100×10μm. The detector is clinged to an Al2O3 substrate with some electrical insulated epoxy glue which is mounted onto a Cu sink. The surrounding temperature is controlled precisely by a temperature controller with a precision of 1mK. Voltage-current characteristics at 270-330K are carefully examined. Different sweeping speeds of the bias-voltage are applied in different orders so as to find out a proper scanning rate, in which the electrical measurement is proceeded in a state of quasi-thermal equilibrium. According to quasi-thermal equilibrium and the time dependent nominal D.C. power, the temperature increase during the measurement is estimated. The conduction mechanism can be well explained with small polaron theory. Empirical equations are used to describe the thermal dynamic process in the pulsed mode, and the process is also simply simulated via numerical calculations. The experimental results and simulation works will be of some referential value to future studies in uncooled microbolometer made in transition metal oxides.

Effects of temperature and precipitation on grassland bird nesting success as mediated by patch size.

PubMed

Zuckerberg, Benjamin; Ribic, Christine A; McCauley, Lisa A

2018-02-06

Grassland birds are declining faster than any other bird guild across North America. Shrinking ranges and population declines are attributed to widespread habitat loss and increasingly fragmented landscapes of agriculture and other land uses that are misaligned with grassland bird conservation. Concurrent with habitat loss and degradation, temperate grasslands have been disproportionally affected by climate change relative to most other terrestrial biomes. Distributions of grassland birds often correlate with gradients in climate, but few researchers have explored the consequences of weather on the demography of grassland birds inhabiting a range of grassland fragments. To do so, we modeled the effects of temperature and precipitation on nesting success rates of 12 grassland bird species inhabiting a range of grassland patches across North America (21,000 nests from 81 individual studies). Higher amounts of precipitation in the preceding year were associated with higher nesting success, but wetter conditions during the active breeding season reduced nesting success. Extremely cold or hot conditions during the early breeding season were associated with lower rates of nesting success. The direct and indirect influence of temperature and precipitation on nesting success was moderated by grassland patch size. The positive effects of precipitation in the preceding year on nesting success were strongest in relatively small grassland patches and had little effect in large patches. Conversely, warm temperatures reduced nesting success in small grassland patches but increased nesting success in large patches. Mechanisms underlying these differences may be patch-size-induced variation in microclimates and predator activity. Although the exact cause is unclear, large grassland patches, the most common metric of grassland conservation, appears to moderate the effects of weather on grassland-bird demography and could be an effective component of climate-change adaptation. © 2018 Society for Conservation Biology.

Energy budget, oxidative stress and antioxidant in striped hamster acclimated to moderate cold and warm temperatures.

PubMed

Chen, Ke-Xin; Wang, Chun-Ming; Wang, Gui-Ying; Zhao, Zhi-Jun

2014-08-01

The mechanism of the rate of living-free radical theory suggests that higher rate of oxidative metabolism results from greater rate of mitochondria oxidative phosphorylation, leading to a consequent increase in production of free radicals. However, the relation between metabolic rate and oxidative stress is tissue dependent in animals acclimated to cold temperatures. Here we examined oxidative stress, reflected by changes of antioxidant activity and other related markers, in striped hamsters acclimated to moderate cold (15°C), room (23°C) or warm temperature (30°C) for 6 weeks, by which either higher or lower metabolic rate was induced experimentally. Energy intake and the rate of metabolism and nonshivering thermogenesis were increased at 15°C, but decreased at 30°C compared with that at 23°C. Effects of temperatures on the markers of both oxidative stress and antioxidant activities were rarely significant. The percentages of positive correlation between the 11 tissues (brain, BAT, liver, heart, lung, kidneys, stomach, small and large intestine, caecum and skeletal muscle) were 14.5% (8/55) for catalase (CAT), 7.3% (4/55) for the capacity of inhibition of hydroxyl free radical (CIH), 5.5% (3/55) for activities of superoxide dismutase (SOD), 1.8% (1/55) for total antioxidant capacity (T-AOC), 4.3% (2/46) for H2O2 and 11.1% (4/36) for the capacity of inhibition of hydroxyl free radical (CIH). This indicated that the tissue-dependent changes of both oxidative stress and antioxidant activity were less consistent among the different tissues. Finally the data from this study were less consistent with the prediction of the mechanism of the rate of living-free radical theory. Copyright © 2014 Elsevier Ltd. All rights reserved.

Method and apparatus for determination of temperature, neutron absorption cross section and neutron moderating power

DOEpatents

Vagelatos, Nicholas; Steinman, Donald K.; John, Joseph; Young, Jack C.

1981-01-01

A nuclear method and apparatus determines the temperature of a medium by injecting fast neutrons into the medium and detecting returning slow neutrons in three first energy ranges by producing three respective detection signals. The detection signals are combined to produce three derived indicia each systematically related to the population of slow neutrons returning from the medium in a respective one of three second energy ranges, specifically exclusively epithermal neutrons, exclusively substantially all thermal neutrons and exclusively a portion of the thermal neutron spectrum. The derived indicia are compared with calibration indicia similarly systematically related to the population of slow neutrons in the same three second energy ranges returning from similarly irradiated calibration media for which the relationships temperature, neutron absorption cross section and neutron moderating power to such calibration indicia are known. The comparison indicates the temperature at which the calibration indicia correspond to the derived indicia and consequently the temperature of the medium. The neutron absorption cross section and moderating power of the medium can be identified at the same time.

Simulating the moderating effect of a lake on downwind temperatures

NASA Technical Reports Server (NTRS)

Bill, R. G., Jr.; Chen, E.; Sutherland, R. A.; Bartholic, J. F.

1979-01-01

A steady-state, two-dimensional numerical model is used to simulate air temperatures and humidity downwind of a lake at night. Thermal effects of the lake were modelled for the case of moderate and low surface winds under the cold-air advective conditions that occur following the passage of a cold front. Surface temperatures were found to be in good agreement with observations. A comparison of model results with thermal imagery indicated the model successfully predicts the downwind distance for which thermal effects due to the lake are significant.

Fluid inclusions in Martian samples: Clues to early crustal development and the hydrosphere

NASA Technical Reports Server (NTRS)

Brown, Philip E.

1988-01-01

Major questions about Mars that could be illuminated by examining fluid inclusions in Martian samples include: (1) the nature, extent and timing of development (and decline) of the hydrosphere that existed on the planet; and (2) the evolution of the crust. Fluid inclusion analyses of appropriate samples could provide critical data to use in comparison with data derived from analogous terrestrial studies. For this study, sample handling and return restrictions are unlikely to be as restrictive as the needs of other investigators. The main constraint is that the samples not be subjected to excessively high temperatures. An aqueous fluid inclusion trapped at elevated pressure and temperature will commonly consist of liquid water and water vapor at room temperature. Heating (such as is done in the laboratory to fix P-V-T data for the inclusion) results in moderate pressure increases up to the liquid-vapor homogenization temperature followed by a sharp increase in pressure with continued heating because the inclusion is effectively a fixed volume system. This increased pressure can rupture the inclusion; precise limits are dependent on size, shape, and composition as well as the host material.

Pre-cooling moderately enhances visual discrimination during exercise in the heat.

PubMed

Clarke, Neil D; Duncan, Michael J; Smith, Mike; Hankey, Joanne

2017-02-01

Pre-cooling has been reported to attenuate the increase in core temperature, although, information regarding the effects of pre-cooling on cognitive function is limited. The present study investigated the effects of pre-cooling on visual discrimination during exercise in the heat. Eight male recreational runners completed 90 min of treadmill running at 65% [Formula: see text] 2max in the heat [32.4 ± 0.9°C and 46.8 ± 6.4% relative humidity (r.h.)] on two occasions in a randomised, counterbalanced crossover design. Participants underwent pre-cooling by means of water immersion (20.3 ± 0.3°C) for 60 min or remained seated for 60 min in a laboratory (20.2 ± 1.7°C and 60.2 ± 2.5% r.h.). Rectal temperature (T rec ) and mean skin temperature (T skin ) were monitored throughout the protocol. At 30-min intervals participants performed a visual discrimination task. Following pre-cooling, T rec (P = 0.040; [Formula: see text] = 0.48) was moderately lower at 0 and 30 min and T skin (P = 0.003; [Formula: see text] = 0.75) lower to a large extent at 0 min of exercise. Visual discrimination was moderately more accurate at 60 and 90 min of exercise following pre-cooling (P = 0.067; [Formula: see text] = 0.40). Pre-cooling resulted in small improvements in visual discrimination sensitivity (F 1,7  = 2.188; P = 0.183; [Formula: see text] = 0.24), criterion (F 1,7  = 1.298; P = 0.292; [Formula: see text] = 0.16) and bias (F 1,7  = 2.202; P = 0.181; [Formula: see text] = 0.24). Pre-cooling moderately improves visual discrimination accuracy during exercise in the heat.

Lipid and carotenoid cooperation-driven adaptation to light and temperature stress in Synechocystis sp. PCC6803.

PubMed

Zakar, Tomas; Herman, Eva; Vajravel, Sindhujaa; Kovacs, Laszlo; Knoppová, Jana; Komenda, Josef; Domonkos, Ildiko; Kis, Mihaly; Gombos, Zoltan; Laczko-Dobos, Hajnalka

2017-05-01

Polyunsaturated lipids are important components of photosynthetic membranes. Xanthophylls are the main photoprotective agents, can assist in protection against light stress, and are crucial in the recovery from photoinhibition. We generated the xanthophyll- and polyunsaturated lipid-deficient ROAD mutant of Synechocystis sp. PCC6803 (Synechocystis) in order to study the little-known cooperative effects of lipids and carotenoids (Cars). Electron microscopic investigations confirmed that in the absence of xanthophylls the S-layer of the cellular envelope is missing. In wild-type (WT) cells, as well as the xanthophyll-less (RO), polyunsaturated lipid-less (AD), and the newly constructed ROAD mutants the lipid and Car compositions were determined by MS and HPLC, respectively. We found that, relative to the WT, the lipid composition of the mutants was remodeled and the Car content changed accordingly. In the mutants the ratio of non-bilayer-forming (NBL) to bilayer-forming (BL) lipids was found considerably lower. Xanthophyll to β-carotene ratio increased in the AD mutant. In vitro and in vivo methods demonstrated that saturated, monounsaturated lipids and xanthophylls may stabilize the trimerization of Photosystem I (PSI). Fluorescence induction and oxygen-evolving activity measurements revealed increased light sensitivity of RO cells compared to those of the WT. ROAD showed a robust increase in light susceptibility and reduced recovery capability, especially at moderate low (ML) and moderate high (MH) temperatures, indicating a cooperative effect of xanthophylls and polyunsaturated lipids. We suggest that both lipid unsaturation and xanthophylls are required for providing the proper structure and functioning of the membrane environment that protects against light and temperature stress. Copyright © 2017 Elsevier B.V. All rights reserved.

Relation of Total and Cardiovascular Death Rates to Climate System, Temperature, Barometric Pressure, and Respiratory Infection.

PubMed

Schwartz, Bryan G; Qualls, Clifford; Kloner, Robert A; Laskey, Warren K

2015-10-15

A distinct seasonal pattern in total and cardiovascular death rates has been reported. The factors contributing to this pattern have not been fully explored. Seven locations (average total population 71,354,000) were selected where data were available including relatively warm, cold, and moderate temperatures. Over the period 2004 to 2009, there were 2,526,123 all-cause deaths, 838,264 circulatory deaths, 255,273 coronary heart disease deaths, and 135,801 ST-elevation myocardial infarction (STEMI) deaths. We used time series and multivariate regression modeling to explore the association between death rates and climatic factors (temperature, dew point, precipitation, barometric pressure), influenza levels, air pollution levels, hours of daylight, and day of week. Average seasonal patterns for all-cause and cardiovascular deaths were very similar across the 7 locations despite differences in climate. After adjusting for multiple covariates and potential confounders, there was a 0.49% increase in all-cause death rate for every 1°C decrease. In general, all-cause, circulatory, coronary heart disease and STEMI death rates increased linearly with decreasing temperatures. The temperature effect varied by location, including temperature's linear slope, cubic fit, positional shift on the temperature axis, and the presence of circulatory death increases in locally hot temperatures. The variable effect of temperature by location suggests that people acclimatize to local temperature cycles. All-cause and circulatory death rates also demonstrated sizable associations with influenza levels, dew point temperature, and barometric pressure. A greater understanding of how climate, temperature, and barometric pressure influence cardiovascular responses would enhance our understanding of circulatory and STEMI deaths. Copyright © 2015 Elsevier Inc. All rights reserved.

Model-based identification of optimal operating conditions for amino acid simulated moving bed enantioseparation using a macrocyclic glycopeptide stationary phase.

PubMed

Fuereder, Markus; Majeed, Imthiyas N; Panke, Sven; Bechtold, Matthias

2014-06-13

Teicoplanin aglycone columns allow efficient separation of amino acid enantiomers in aqueous mobile phases and enable robust and predictable simulated moving bed (SMB) separation of racemic methionine despite a dependency of the adsorption behavior on the column history (memory effect). In this work we systematically investigated the influence of the mobile phase (methanol content) and temperature on SMB performance using a model-based optimization approach that accounts for methionine solubility, adsorption behavior and back pressure. Adsorption isotherms became more favorable with increasing methanol content but methionine solubility was decreased and back pressure increased. Numerical optimization suggested a moderate methanol content (25-35%) for most efficient operation. Higher temperature had a positive effect on specific productivity and desorbent requirement due to higher methionine solubility, lower back pressure and virtually invariant selectivity at high loadings of racemic methionine. However, process robustness (defined as a difference in flow rate ratios) decreased strongly with increasing temperature to the extent that any significant increase in temperature over 32°C will likely result in operating points that cannot be realized technically even with the lab-scale piston pump SMB system employed in this study. Copyright © 2014. Published by Elsevier B.V.

Influence of Off-Centre Operation on the Performance of HTS Maglev

NASA Astrophysics Data System (ADS)

Gou, Y.; He, D.; Zheng, J.; Ye, C.; Xu, Y.; Sun, R.; Che, T.; Deng, Z.

2014-03-01

Owing to instinctive self-stable levitation characteristics, high-temperature superconducting (HTS) maglev using bulk high-temperature superconductors attracts more and more attention from scientists and engineers around the world. In this paper, the levitation force relaxation and guidance force characteristics of a Y-Ba-Cu-O levitation unit with different eccentric distances (EDs) off the center of the permanent magnet guideway were experimentally investigated under field-cooling (FC) conditions. Experimental results indicate that the levitation force slightly increases at small EDs firstly, but degrades with further increasing of EDs. However, the maximum guidance force and its stiffness exhibit enhancement in moderate ED range. The results demonstrate that a properly designed initial FC eccentric distance is important for the practical applications of HTS maglev according to specific requirements like running in curve lines.

Water source protection funds as a tool to address climate adaptation and resiliency in southwestern forests

Treesearch

Laura Falk McCarthy

2014-01-01

Wildfire intensity in the Southwestern United States has increased over the last decade corresponding with dense fuels and higher temperatures. For example, in New Mexico on the 2011 Las Conchas fire, intense fire and wind-driven fire behavior resulted in large areas of moderate and high severity burn (42 percent of burned area) with roughly 65,000 acres (26,300 ha)...

Influence of Nanoinclusions on Thermoelectric Properties of n-Type Bi2Te3 Nanocomposites

NASA Astrophysics Data System (ADS)

Fan, Shufen; Zhao, Junnan; Yan, Qingyu; Ma, Jan; Hng, Huey Hoon

2011-05-01

n-Type Bi2Te3 nanocomposites with enhanced figure of merit, ZT, were fabricated by a simple, high-throughput method of mixing nanostructured Bi2Te3 particles obtained through melt spinning with micron-sized particles. Moderately high power factors were retained, while the thermal conductivity of the nanocomposites was found to decrease with increasing weight percent of nanoinclusions. The peak ZT values for all the nanocomposites were above 1.1, and the maximum shifted to higher temperature with increasing amount of nanoinclusions. A maximum ZT of 1.18 at 42°C was obtained for the 10 wt.% nanocomposite, which is a 43% increase over the bulk sample at the same temperature. This is the highest ZT reported for n-type Bi2Te3 binary material, and higher ZT values are expected if state-of-the-art Bi2Te3- x Se x materials are used.

Influence of body heat content on hand function during prolonged cold exposures.

PubMed

Flouris, A D; Cheung, S S; Fowles, J R; Kruisselbrink, L D; Westwood, D A; Carrillo, A E; Murphy, R J L

2006-09-01

We examined the influence of 1) prior increase [preheating (PHT)], 2) increase throughout [heating (HT)], and 3) no increase [control (Con)] of body heat content (H(b)) on neuromuscular function and manual dexterity of the hands during a 130-min exposure to -20 degrees C (coldEx). Ten volunteers randomly underwent three passive coldEx, incorporating a 10-min moderate-exercise period at the 65th min while wearing a liquid conditioning garment (LCG) and military arctic clothing. In PHT, 50 degrees C water was circulated in the LCG before coldEx until core temperature was increased by 0.5 degrees C. In HT, participants regulated the inlet LCG water temperature throughout coldEx to subjective comfort, while the LCG was not operating in Con. Thermal comfort, rectal temperature, mean skin temperature, mean finger temperature (T(fing)), change in H(b) (DeltaH(b)), rate of body heat storage, Purdue pegboard test, finger tapping, handgrip, maximum voluntary contraction, and evoked twitch force of the first dorsal interosseus muscle were recorded. Results demonstrated that, unlike in HT and PHT, thermal comfort, rectal temperature, mean skin temperature, twitch force, maximum voluntary contraction, and finger tapping declined significantly in Con. In contrast, T(fing) and Purdue pegboard test remained constant only in HT. Generalized estimating equations demonstrated that DeltaH(b) and T(fing) were associated over time with hand function, whereas no significant association was detected for rate of body heat storage. It is concluded that increasing H(b) not only throughout but also before a coldEx is effective in maintaining hand function. In addition, we found that the best indicator of hand function is DeltaH(b) followed by T(fing).

Gaseous elemental mercury (GEM) fluxes over canopy of two typical subtropical forests in south China

NASA Astrophysics Data System (ADS)

Yu, Qian; Luo, Yao; Wang, Shuxiao; Wang, Zhiqi; Hao, Jiming; Duan, Lei

2018-01-01

Mercury (Hg) exchange between forests and the atmosphere plays an important role in global Hg cycling. The present estimate of global emission of Hg from natural source has large uncertainty, partly due to the lack of chronical and valid field data, particularly for terrestrial surfaces in China, the most important contributor to global atmospheric Hg. In this study, the micrometeorological method (MM) was used to continuously observe gaseous elemental mercury (GEM) fluxes over forest canopy at a mildly polluted site (Qianyanzhou, QYZ) and a moderately polluted site (Huitong, HT, near a large Hg mine) in subtropical south China for a full year from January to December in 2014. The GEM flux measurements over forest canopy in QYZ and HT showed net emission with annual average values of 6.67 and 0.30 ng m-2 h-1, respectively. Daily variations of GEM fluxes showed an increasing emission with the increasing air temperature and solar radiation in the daytime to a peak at 13:00, and decreasing emission thereafter, even as a GEM sink or balance at night. High temperature and low air Hg concentration resulted in the high Hg emission in summer. Low temperature in winter and Hg absorption by plant in spring resulted in low Hg emission, or even adsorption in the two seasons. GEM fluxes were positively correlated with air temperature, soil temperature, wind speed, and solar radiation, while it is negatively correlated with air humidity and atmospheric GEM concentration. The lower emission fluxes of GEM at the moderately polluted site (HT) when compared with that in the mildly polluted site (QYZ) may result from a much higher adsorption fluxes at night in spite of a similar or higher emission fluxes during daytime. This shows that the higher atmospheric GEM concentration at HT restricted the forest GEM emission. Great attention should be paid to forests as a crucial increasing Hg emission source with the decreasing atmospheric GEM concentration in polluted areas because of Hg emission abatement in the future.

Muscle metabolism, temperature, and function during prolonged, intermittent, high-intensity running in air temperatures of 33 degrees and 17 degrees C.

PubMed

Morris, J G; Nevill, M E; Boobis, L H; Macdonald, I A; Williams, C

2005-12-01

Nine unacclimatized university sportsmen performed a prolonged, intermittent, high-intensity shuttle running test in hot (HT) (33 degrees C, dry bulb temperature, approximately 28 %, relative humidity) and moderate (MT) (17 degrees C, 63 %) environmental conditions. Subjects performed 60 m of walking, a 15-m sprint, 60 m of cruising ( approximately 85 % V.O (2max)), and 60 m of jogging ( approximately 45 %V.O (2max)) for 14.8 +/- 0.1 min followed by a 3-min rest, repeated until volitional exhaustion. The hot trial was performed first followed, 14 days later, by the moderate trial. During exercise subjects drank water ad libitum. Subjects ran almost twice as far in the moderate as in the hot trial (HT 11216 +/- 1411, MT 21644 +/- 1629, m, p < 0.01), and the decline in average 15-m sprint performance was greater in the heat (HT, 0.17 +/- 0.05, MT, 0.09 +/- 0.03, s, p < 0.05). Average heart rates, blood lactate and glucose, and plasma adrenaline and noradrenaline concentrations were greater in the HT (main effect trial, p < 0.01), as were serum cortisol concentration (main effect trial p < 0.05, n = 5) and muscle temperature (HT exhaustion vs. same time point in MT, 40.2 +/- 0.3 vs. 39.3 +/- 0.2, degrees C, p < 0.01). Peak torque during knee flexion and extension was not different pre-and post-exercise in the HT. Muscle glycogen utilization tended to be greater in the heat (HT 193.2 +/- 19.5, MT 143.8 +/- 23.9, mmol . kg dry wt (-1), p = 0.055, n = 8). In 7 out of the 8 subjects the increase in utilization was between 19 and just over 200 % greater in the HT. Glycogen remaining in the muscle at exhaustion was greater in the hot than moderate trial (HT 207.4 +/- 34.3, MT 126.5 +/- 46.8, mmol . kg dry wt (-1), p < 0.01, n = 8). Rectal temperature (T (rec)) was higher in the HT at exhaustion than at the same point in time in the moderate trial (HT, 39.60 +/- 0.15 vs. MT 38.75 +/- 0.10, degrees C, interaction trial-time, p < 0.01). There was a very strong negative relationship between rate of rise in T (rec) and distance completed in the HT (HT r = - 0.90, p < 0.01, MT r = - 0.76, p < 0.05). Thus, the earlier onset of exhaustion during prolonged intermittent shuttle running in the heat is associated with hyperthermia. However, while muscle glycogen utilization may be elevated by heat stress, low whole muscle glycogen concentrations would not seem to be the cause of this earlier exhaustion.

A Canonical Response in Rainfall Characteristics to Global Warming: Projections by IPCC CMIP5 Models

NASA Technical Reports Server (NTRS)

Lau, William K. M.; Wu, H. T.; Kim, K. M.

2012-01-01

Changes in rainfall characteristics induced by global warming are examined based on probability distribution function (PDF) analysis, from outputs of 14 IPCC (Intergovernmental Panel on Climate Change), CMIP (5th Coupled Model Intercomparison Project) models under various scenarios of increased CO2 emissions. Results show that collectively CMIP5 models project a robust and consistent global and regional rainfall response to CO2 warming. Globally, the models show a 1-3% increase in rainfall per degree rise in temperature, with a canonical response featuring large increase (100-250 %) in frequency of occurrence of very heavy rain, a reduction (5-10%) of moderate rain, and an increase (10-15%) of light rain events. Regionally, even though details vary among models, a majority of the models (>10 out of 14) project a consistent large scale response with more heavy rain events in climatologically wet regions, most pronounced in the Pacific ITCZ and the Asian monsoon. Moderate rain events are found to decrease over extensive regions of the subtropical and extratropical oceans, but increases over the extratropical land regions, and the Southern Oceans. The spatial distribution of light rain resembles that of moderate rain, but mostly with opposite polarity. The majority of the models also show increase in the number of dry events (absence or only trace amount of rain) over subtropical and tropical land regions in both hemispheres. These results suggest that rainfall characteristics are changing and that increased extreme rainfall events and droughts occurrences are connected, as a consequent of a global adjustment of the large scale circulation to global warming.

Implications for organic maturation studies of evidence of a geologically rapid increase and stabilization of vitrinite reflectance at peak temperature: Cerro Prieto geothermal system, Mexico

USGS Publications Warehouse

Barker, C.E.

1991-01-01

A short-term rapid heating and cooling of the rock in well M-94 below 1300 m was caused by a pulse of hot water passing through the edge of the Cerro Prieto, Mexico, geothermal system. Below 1300 m, the peak paleotemperatures were about 225-250??C, but equilibrium well log temperatures indicate a decrease to 150-210??C at present. This hot water pulse sharply increased vitrinite reflectance to levels comparable to those measured in the central part of the system, even though studies of apatite fission-track annealing indicate that the duration of heating was only 100-101 yr in M-94, in contrast to 103-104 yr in the central part of the system. The quick change of the vitrinite reflectance geothermometer indicates that thermal maturation reactions can stabilize, after a geologically short period of heating, to a level consistent with peak temperature under moderate to high-temperature diagenesis in open, fluid-rich, geothermal systems. -from Author

Rapid process for producing transparent, monolithic porous glass

DOEpatents

Coronado, Paul R [Livermore, CA

2006-02-14

A process for making transparent porous glass monoliths from gels. The glass is produced much faster and in much larger sizes than present technology for making porous glass. The process reduces the cost of making large porous glass monoliths because: 1) the process does not require solvent exchange nor additives to the gel to increase the drying rates, 2) only moderate temperatures and pressures are used so relatively inexpensive equipment is needed, an 3) net-shape glass monoliths are possible using this process. The process depends on the use of temperature to control the partial pressure of the gel solvent in a closed vessel, resulting in controlled shrinking during drying.

Estimating the stability of electrical conductivity of filled polymers under the influence of negative temperatures

NASA Astrophysics Data System (ADS)

Minakova, N. N.; Ushakov, V. Ya.

2017-12-01

One of the key problems in modern materials technology is synthesis of materials for electrotechnical devices capable of operating under severe conditions. Electrical and power engineering, in particular, demands for electrically conductive composite materials operating at high and low temperatures, various mechanical loads, electric fields, etc. Chaotic arrangement of electrically conductive component in the matrix and its structural and geometrical inhomogeneity can increase the local electric and thermal energy flux densities up to critical values even when their average values remain moderate. Elastomers filled with technical carbon being a promising component for electrotechnical devices was chosen as an object of study.

Anomalous maximum and minimum for the dissociation of a geminate pair in energetically disordered media

NASA Astrophysics Data System (ADS)

Govatski, J. A.; da Luz, M. G. E.; Koehler, M.

2015-01-01

We study the geminated pair dissociation probability φ as function of applied electric field and temperature in energetically disordered nD media. Regardless nD, for certain parameters regions φ versus the disorder degree (σ) displays anomalous minimum (maximum) at low (moderate) fields. This behavior is compatible with a transport energy which reaches a maximum and then decreases to negative values as σ increases. Our results explain the temperature dependence of the persistent photoconductivity in C60 single crystals going through order-disorder transitions. They also indicate how an energetic disorder spatial variation may contribute to higher exciton dissociation in multicomponent donor/acceptor systems.

Thermoelectric current in topological insulator nanowires with impurities.

PubMed

Erlingsson, Sigurdur I; Bardarson, Jens H; Manolescu, Andrei

2018-01-01

In this paper we consider charge current generated by maintaining a temperature difference over a nanowire at zero voltage bias. For topological insulator nanowires in a perpendicular magnetic field the current can change sign as the temperature of one end is increased. Here we study how this thermoelectric current sign reversal depends on the magnetic field and how impurities affect the size of the thermoelectric current. We consider both scalar and magnetic impurities and show that their influence on the current are quite similar, although the magnetic impurities seem to be more effective in reducing the effect. For moderate impurity concentration the sign reversal persists.

Sensitivity of cold acclimation to elevated autumn temperature in field-grown Pinus strobus seedlings

PubMed Central

Chang, Christine Y.; Unda, Faride; Zubilewich, Alexandra; Mansfield, Shawn D.; Ensminger, Ingo

2015-01-01

Climate change will increase autumn air temperature, while photoperiod decrease will remain unaffected. We assessed the effect of increased autumn air temperature on timing and development of cold acclimation and freezing resistance in Eastern white pine (EWP, Pinus strobus) under field conditions. For this purpose we simulated projected warmer temperatures for southern Ontario in a Temperature Free-Air-Controlled Enhancement (T-FACE) experiment and exposed EWP seedlings to ambient (Control) or elevated temperature (ET, +1.5°C/+3°C during day/night). Photosynthetic gas exchange, chlorophyll fluorescence, photoprotective pigments, leaf non-structural carbohydrates (NSC), and cold hardiness were assessed over two consecutive autumns. Nighttime temperature below 10°C and photoperiod below 12 h initiated downregulation of assimilation in both treatments. When temperature further decreased to 0°C and photoperiod became shorter than 10 h, downregulation of the light reactions and upregulation of photoprotective mechanisms occurred in both treatments. While ET seedlings did not delay the timing of the downregulation of assimilation, stomatal conductance in ET seedlings was decreased by 20–30% between August and early October. In both treatments leaf NSC composition changed considerably during autumn but differences between Control and ET seedlings were not significant. Similarly, development of freezing resistance was induced by exposure to low temperature during autumn, but the timing was not delayed in ET seedlings compared to Control seedlings. Our results indicate that EWP is most sensitive to temperature changes during October and November when downregulation of photosynthesis, enhancement of photoprotection, synthesis of cold-associated NSCs and development of freezing resistance occur. However, we also conclude that the timing of the development of freezing resistance in EWP seedlings is not affected by moderate temperature increases used in our field experiments. PMID:25852717

Spatiotemporal distribution and the characteristics of the air temperature of a river source region of the Qinghai-Tibet Plateau.

PubMed

Deng, Cai; Zhang, Wanchang

2018-05-30

As the backland of the Qinghai-Tibet Plateau, the river source region is highly sensitive to changes in global climate. Air temperature estimation using remote sensing satellite provides a new way of conducting studies in the field of climate change study. A geographically weighted regression model was applied to estimate synchronic air temperature from 2001 to 2015 using Moderate-Resolution Imaging Spectroradiometry (MODIS) data. The results were R 2  = 0.913 and RMSE = 2.47 °C, which confirmed the feasibility of the estimation. The spatial distribution and variation characteristics of the average annual and seasonal air temperature were analyzed. The findings are as follows: (1) the distribution of average annual air temperature has significant terrain characteristics. The reduction in average annual air temperature along the elevation of the region is 0.19 °C/km, whereas the reduction in the average annual air temperature along the latitude is 0.04 °C/degree. (2) The average annual air temperature increase in the region is 0.37 °C/decade. The average air temperature increase could be arranged in the following decreasing order: Yangtze River Basin > Mekong River Basin > Nujiang River Basin > Yarlung Zangbo River Basin > Yellow River Basin. The fastest, namely, Yangtze River Basin, is 0.47 °C/decade. (3) The average air temperature rise in spring, summer, and winter generally increases with higher altitude. The average annual air temperature in different types of lands following a decreasing order is as follows: wetland > construction land > bare land glacier > shrub grassland > arable land > forest land > water body and that of the fastest one, wetland, is 0.13 °C/year.

Climate change in Canadian forests: Effect of global warming and CO2 fertilization on natural populations of black and white spruce

NASA Astrophysics Data System (ADS)

Nelson, E. A.; Thomas, S. C.

2007-12-01

Global increases in temperature and atmospheric CO2 concentration are predicted to enhance tree growth in the short term, but studies of current impacts of climate change on Canada's forests are limited. This study examined the effects of increasing temperature and atmospheric CO2 concentration on tree ring growth in west-central Manitoba and northern Ontario, sampling white spruce (Picea glauca) and black spruce (Picea mariana), respectively. Over 50 tree cores from each site were sampled, analysed for ring-width, cross-dated and detrended, generating a ~100 y chronology for each population. We found a positive correlation between ring-width increment and spring temperatures (April-May: p<0.005) in Ontario. In Manitoba, however, we found a negative correlation between summer temperatures (Jul-Aug: p<0.005) and ring-width increment coincident with a positive relationship with summer precipitation (July: p<0.03). We examined the residuals following a regression with temperature for a positive trend over time, which has been interpreted in prior studies as evidence for a CO2 fertilization effect. We detected no such putative CO2 fertilization signal in either spruce population. Our results suggest that temperature-limited lowland black spruce communities may respond positively to moderate warming, but that water-limited upland white spruce communities may suffer from drought stress under high temperature conditions. Neither population appears to benefit from increasing CO2 availability.

A Climate-Data Record (CDR) of the "Clear-Sky" Surface Temperature of the Greenland Ice Sheet

NASA Technical Reports Server (NTRS)

Hall, Dorothy K.; Comiso, Josefino C.; DiGirolamo, Nocolo E.; Shuman, Christopher A.

2011-01-01

We have developed a climate-data record (CDR) of "clear-sky" ice-surface temperature (IST) of the Greenland Ice Sheet using Moderate-Resolution Imaging Spectroradiometer (MODIS) data. The CDR provides daily and monthly-mean IST from March 2000 through December 2010 on a polar stereographic projection at a resolution of 6.25 km. The CDR is amenable to extension into the future using Visible/Infrared Imager Radiometer Suite (VIIRS) data. Regional "clear-sky" surface temperature increases since the early 1980s in the Arctic, measured using Advanced Very High Resolution Radiometer (AVHRR) infrared data, range from 0.57 +/- 0.02 to 0.72 +/- 0.1 c per decade. Arctic warming has important implications for ice-sheet mass balance because much of the periphery of the Greenland Ice Sheet is already near O C during the melt season, and is thus vulnerable to rapid melting if temperatures continue to increase. An increase in melting of the ice sheet would accelerate sea-level rise, an issue affecting potentially billions of people worldwide. The IST CDR will provide a convenient data set for modelers and for climatologists to track changes of the surface temperature of the ice sheet as a whole and of the individual drainage basins on the ice sheet. The daily and monthly maps will provide information on surface melt as well as "clear-sky" temperature. The CDR will be further validated by comparing results with automatic-weather station data and with satellite-derived surface-temperature products.

Effect of core body temperature, time of day, and climate conditions on behavioral patterns of lactating dairy cows experiencing mild to moderate heat stress.

PubMed

Allen, J D; Hall, L W; Collier, R J; Smith, J F

2015-01-01

Cattle show several responses to heat load, including spending more time standing. Little is known about what benefit this may provide for the animals. Data from 3 separate cooling management trials were analyzed to investigate the relationship between behavioral patterns in lactating dairy cows experiencing mild to moderate heat stress and their body temperature. Cows (n=157) were each fitted with a leg data logger that measured position and an intravaginal data logger that measures core body temperature (CBT). Ambient conditions were also collected. All data were standardized to 5-min intervals, and information was divided into several categories: when standing and lying bouts were initiated and the continuance of each bout (7,963 lying and 6,276 standing bouts). In one location, cows were continuously subjected to heat-stress levels according to temperature-humidity index (THI) range (THI≥72). The THI range for the other 2 locations was below and above a heat-stress threshold of 72 THI. Overall and regardless of period of day, cows stood up at greater CBT compared with continuing to stand or switching to a lying position. In contrast, cows lay down at lower CBT compared with continuing to lie or switching to a standing position, and lying bouts lasted longer when cows had lower CBT. Standing bouts also lasted longer when cattle had greater CBT, and they were less likely to lie down (less than 50% of lying bouts initiated) when their body temperature was over 38.8°C. Also, cow standing behavior was affected once THI reached 68. Increasing CBT decreased lying duration and increased standing duration. A CBT of 38.93°C marked a 50% likelihood a cow would be standing. This is the first physiological evidence that standing may help cool cows and provides insight into a communally observed behavioral response to heat. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

The effects of temperature on the stability of a neuronal oscillator.

PubMed

Rinberg, Anatoly; Taylor, Adam L; Marder, Eve

2013-01-01

The crab Cancer borealis undergoes large daily fluctuations in environmental temperature (8-24°C) and must maintain appropriate neural function in the face of this perturbation. In the pyloric circuit of the crab stomatogastric ganglion, we pharmacologically isolated the pacemaker kernel (the AB and PD neurons) and characterized its behavior in response to temperature ramps from 7°C to 31°C. For moderate temperatures, the pacemaker displayed a frequency-temperature curve statistically indistinguishable from that of the intact circuit, and like the intact circuit maintained a constant duty cycle. At high temperatures (above 23°C), a variety of different behaviors were seen: in some preparations the pacemaker increased in frequency, in some it slowed, and in many preparations the pacemaker stopped oscillating ("crashed"). Furthermore, these crashes seemed to fall into two qualitatively different classes. Additionally, the animal-to-animal variability in frequency increased at high temperatures. We used a series of Morris-Lecar mathematical models to gain insight into these phenomena. The biophysical components of the final model have temperature sensitivities similar to those found in nature, and can crash via two qualitatively different mechanisms that resemble those observed experimentally. The crash type is determined by the precise parameters of the model at the reference temperature, 11°C, which could explain why some preparations seem to crash in one way and some in another. Furthermore, even models with very similar behavior at the reference temperature diverge greatly at high temperatures, resembling the experimental observations.

Measurement of charged-particle stopping in warm-dense plasma

DOE PAGES

Zylstra, A.  B.; Frenje, J.  A.; Grabowski, P. E.; ...

2015-05-27

We measured the stopping of energetic protons in an isochorically-heated solid-density Be plasma with an electron temperature of ~32 eV, corresponding to moderately-coupled [(e²/a/(k BT e + E F ) ~ 0.3] and moderately-degenerate [k BT e/E F ~2] 'warm dense matter' (WDM) conditions. We present the first high-accuracy measurements of charged-particle energy loss through dense plasma, which shows an increased loss relative to cold matter, consistent with a reduced mean ionization potential. The data agree with stopping models based on an ad-hoc treatment of free and bound electrons, as well as the average-atom local-density approximation; this work is themore » first test of these theories in WDM plasma.« less

Temperature Measurements in Dynamically-loaded Systems Using Neutron Resonance Spectroscopy (NRS) at LANSCE

NASA Astrophysics Data System (ADS)

Yuan, V. W.

2002-12-01

In previous attempts to determine the internal temperature in systems subjected to dynamic loading, experimenters have usually relied on surface-based optical techniques that are often hampered by insufficient information regarding the emissivity of the surfaces under study. Neutron Resonance Spectroscopy (NRS) is a technique that uses Doppler-broadened neutron resonances to measure internal temperatures in dynamically-loaded samples. NRS has developed its own target-moderator assembly to provide single pulses with an order of magnitude higher brightness than the Lujan production target. The resonance line shapes from which temperature information is extracted are also influenced by non-temperature-dependent broadening from the moderator and detector phosphorescence. Dynamic NRS experiments have been performed to measure the temperature in a silver sheet jet and behind the passage of a shock wave in molybdenum.

New Evidence on the Relationship Between Climate and Conflict

NASA Astrophysics Data System (ADS)

Burke, M.

2015-12-01

We synthesize a large new body of research on the relationship between climate and conflict. We consider many types of human conflict, ranging from interpersonal conflict -- domestic violence, road rage, assault, murder, and rape -- to intergroup conflict -- riots, coups, ethnic violence, land invasions, gang violence, and civil war. After harmonizing statistical specifications and standardizing estimated effect sizes within each conflict category, we implement a meta-analysis that allows us to estimate the mean effect of climate variation on conflict outcomes as well as quantify the degree of variability in this effect size across studies. Looking across more than 50 studies, we find that deviations from moderate temperatures and precipitation patterns systematically increase the risk of conflict, often substantially, with average effects that are highly statistically significant. We find that contemporaneous temperature has the largest average effect by far, with each 1 standard deviation increase toward warmer temperatures increasing the frequency of contemporaneous interpersonal conflict by 2% and of intergroup conflict by more than 10%. We also quantify substantial heterogeneity in these effect estimates across settings.

Acoustic near-field characteristics of a conical, premixed flame

NASA Astrophysics Data System (ADS)

Lee, Doh-Hyoung; Lieuwen, Tim C.

2003-01-01

The occurrence of self-excited pressure oscillations routinely plagues the development of combustion systems. These oscillations are often driven by interactions between the flame and acoustic perturbations. This study was performed to characterize the structure of the acoustic field in the near field of the flame and the manner in which it is influenced by oscillation frequency, combustor geometry, flame length and temperature ratio. The results of these calculations indicate that the acoustic velocity has primarily one- and two-dimensional features near the flame tip and base, respectively. The magnitude of the radial velocity components increases with temperature ratio across the flame, while their axial extent increases with frequency. However, the acoustic pressure has primarily one-dimensional characteristics. They also show that the acoustic field structure exhibits only moderate dependencies upon area expansion and flame temperature ratio for values typical of practical systems. Finally, they show that the local characteristics of the acoustic field, as well as the overall plane-wave reflection coefficient, exhibit a decreasing dependence upon the flame length as the area expansion ratio increases.

Acoustic near-field characteristics of a conical, premixed flame.

PubMed

Lee, Doh-Hyoung; Lieuwen, Tim C

2003-01-01

The occurrence of self-excited pressure oscillations routinely plagues the development of combustion systems. These oscillations are often driven by interactions between the flame and acoustic perturbations. This study was performed to characterize the structure of the acoustic field in the near field of the flame and the manner in which it is influenced by oscillation frequency, combustor geometry, flame length and temperature ratio. The results of these calculations indicate that the acoustic velocity has primarily one- and two-dimensional features near the flame tip and base, respectively. The magnitude of the radial velocity components increases with temperature ratio across the flame, while their axial extent increases with frequency. However, the acoustic pressure has primarily one-dimensional characteristics. They also show that the acoustic field structure exhibits only moderate dependencies upon area expansion and flame temperature ratio for values typical of practical systems. Finally, they show that the local characteristics of the acoustic field, as well as the overall plane-wave reflection coefficient, exhibit a decreasing dependence upon the flame length as the area expansion ratio increases.

Cold-Adapted Enzymes

NASA Astrophysics Data System (ADS)

Georlette, D.; Bentahir, M.; Claverie, P.; Collins, T.; D'amico, S.; Delille, D.; Feller, G.; Gratia, E.; Hoyoux, A.; Lonhienne, T.; Meuwis, M.-a.; Zecchinon, L.; Gerday, Ch.

In the last few years, increased attention has been focused on enzymes produced by cold-adapted micro-organisms. It has emerged that psychrophilic enzymes represent an extremely powerful tool in both protein folding investigations and for biotechnological purposes. Such enzymes are characterised by an increased thermosensitivity and, most of them, by a higher catalytic efficiency at low and moderate temperatures, when compared to their mesophilic counterparts. The high thermosensitivity probably originates from an increased flexibility of either a selected area of the molecular edifice or the overall protein structure, providing enhanced abilities to undergo conformational changes during catalysis at low temperatures. Structure modelling and recent crystallographic data have allowed to elucidate the structural parameters that could be involved in this higher resilience. It was demonstrated that each psychrophilic enzyme adopts its own adaptive strategy. It appears, moreover, that there is a continuum in the strategy of protein adaptation to temperature, as the previously mentioned structural parameters are implicated in the stability of thermophilic proteins. Additional 3D crystal structures, site-directed and random mutagenesis experiments should now be undertaken to further investigate the stability-flexibility-activity relationship.

Suitability assessment and mapping of Oyo State, Nigeria, for rice cultivation using GIS

NASA Astrophysics Data System (ADS)

Ayoade, Modupe Alake

2017-08-01

Rice is one of the most preferred food crops in Nigeria. However, local rice production has declined with the oil boom of the 1970s causing demand to outstrip supply. Rice production can be increased through the integration of Geographic Information Systems (GIS) and crop-land suitability analysis and mapping. Based on the key predictor variables that determine rice yield mentioned in relevant literature, data on rainfall, temperature, relative humidity, slope, and soil of Oyo state were obtained. To develop rice suitability maps for the state, two MCE-GIS techniques, namely the Overlay approach and weighted linear combination (WLC), using fuzzy AHP were used and compared. A Boolean land use map derived from a landsat imagery was used in masking out areas currently unavailable for rice production. Both suitability maps were classified into four categories of very suitable, suitable, moderate, and fairly moderate. Although the maps differ slightly, the overlay and WLC (AHP) approach found most parts of Oyo state (51.79 and 82.9 % respectively) to be moderately suitable for rice production. However, in areas like Eruwa, Oyo, and Shaki, rainfall amount received needs to be supplemented by irrigation for increased rice yield.

Temperature dependencies of Henry’s law constants for different plant sesquiterpenes

PubMed Central

Copolovici, Lucian; Niinemets, Ülo

2018-01-01

Sesquiterpenes are plant-produced hydrocarbons with important ecological functions in plant-to-plant and plant-to-insect communication, but due to their high reactivity they can also play a significant role in atmospheric chemistry. So far, there is little information of gas/liquid phase partition coefficients (Henry’s law constants) and their temperature dependencies for sesquiterpenes, but this information is needed for quantitative simulation of the release of sesquiterpenes from plants and modeling atmospheric reactions in different phases. In this study, we estimated Henry’s law constants (Hpc) and their temperature responses for 12 key plant sesquiterpenes with varying structure (aliphatic, mono-, bi- and tricyclic sesquiterpenes). At 25 °C, Henry’s law constants varied 1.4-fold among different sesquiterpenes, and the values were within the range previously observed for monocyclic monoterpenes. Hpc of sesquiterpenes exhibited a high rate of increase, on average ca. 1.5-fold with a 10 °C increase in temperature (Q10). The values of Q10 varied 1.2-fold among different sesquiterpenes. Overall, these data demonstrate moderately high variation in Hpc values and Hpc temperature responses among different sesquiterpenes. We argue that these variations can importantly alter the emission kinetics of sesquiterpenes from plants. PMID:26291755

How Close Are We to the Temperature Tipping Point of the Biosphere?

NASA Astrophysics Data System (ADS)

Duffy, K. H.

2017-12-01

All biological processes accelerate rapidly with increasing temperature (Tinf); reaching a maximum rate (Tmax), after which they decline. However different biological processes may not be synchronised in their response to increasing temperatures resulting in major dis-equilibria of ecosystem processes. Particularly, the linked processes of photosynthesis and respiration have different curvature that is determined by their inherent sensitivity to temperature. Constraining the difference in temperature curves between photosynthesis and respiration allows us to quantify changes to global carbon metabolism and the land sink of carbon as a whole. During the last century the biosphere has acted as a sink of carbon from the atmosphere partly mitigating accumulation of CO2 derived from burning of fossil fuels Here we ask the following questions: As global temperature increases will photosynthesis and respiration become de-coupled and when? What is Tmax for the land sink, and where is current mean temperature range in regard to this important threshold? At what global and regional temperatures do we expect the biosphere to become a source of carbon to the atmosphere? To address these questions we used the recently released FLUXNET2015 dataset comprised of 212 eddy covariance flux tower sites which concurrently measure land-atmosphere carbon exchange along with micro-meteorological variables. Here, we illustrate our results for Tinf and Tmax of the land sink by biome and for the biosphere as a whole. Our results suggest that recent warming has already pushed us past the inflection point of photosynthesis, and that any additional warming will increase the cumulative annual dose of time spent past Tmax for the land sink. Even under moderate climate projections, we expect to see a slowing of the terrestrial carbon sink by as early as 2040.

Circumpolar dynamics of a marine top-predator track ocean warming rates.

PubMed

Descamps, Sébastien; Anker-Nilssen, Tycho; Barrett, Robert T; Irons, David B; Merkel, Flemming; Robertson, Gregory J; Yoccoz, Nigel G; Mallory, Mark L; Montevecchi, William A; Boertmann, David; Artukhin, Yuri; Christensen-Dalsgaard, Signe; Erikstad, Kjell-Einar; Gilchrist, H Grant; Labansen, Aili L; Lorentsen, Svein-Håkon; Mosbech, Anders; Olsen, Bergur; Petersen, Aevar; Rail, Jean-Francois; Renner, Heather M; Strøm, Hallvard; Systad, Geir H; Wilhelm, Sabina I; Zelenskaya, Larisa

2017-09-01

Global warming is a nonlinear process, and temperature may increase in a stepwise manner. Periods of abrupt warming can trigger persistent changes in the state of ecosystems, also called regime shifts. The responses of organisms to abrupt warming and associated regime shifts can be unlike responses to periods of slow or moderate change. Understanding of nonlinearity in the biological responses to climate warming is needed to assess the consequences of ongoing climate change. Here, we demonstrate that the population dynamics of a long-lived, wide-ranging marine predator are associated with changes in the rate of ocean warming. Data from 556 colonies of black-legged kittiwakes Rissa tridactyla distributed throughout its breeding range revealed that an abrupt warming of sea-surface temperature in the 1990s coincided with steep kittiwake population decline. Periods of moderate warming in sea temperatures did not seem to affect kittiwake dynamics. The rapid warming observed in the 1990s may have driven large-scale, circumpolar marine ecosystem shifts that strongly affected kittiwakes through bottom-up effects. Our study sheds light on the nonlinear response of a circumpolar seabird to large-scale changes in oceanographic conditions and indicates that marine top predators may be more sensitive to the rate of ocean warming rather than to warming itself. © 2017 John Wiley & Sons Ltd.

Effect of limb cooling on peripheral and global oxygen consumption in neonates

PubMed Central

Hassan, I; Wickramasinghe, Y; Spencer, S

2003-01-01

Aim: To evaluate peripheral oxygen consumption (VO2) measurements using near infrared spectroscopy (NIRS) with arterial occlusion in healthy term neonates by studying the effect of limb cooling on peripheral and global VO2. Subjects and methods: Twenty two healthy term neonates were studied. Peripheral VO2 was measured by NIRS using arterial occlusion and measurement of the oxyhaemoglobin (HbO2) decrement slope. Global VO2 was measured by open circuit calorimetry. Global and peripheral VO2 was measured in each neonate before and after limb cooling. Results: In 10 neonates, a fall in forearm temperature of 2.2°C (mild cooling) decreased forearm VO2 by 19.6% (p < 0.01). Global VO2 did not change. In 12 neonates, a fall in forearm temperature of 4°C (moderate cooling) decreased forearm VO2 by 34.7% (p < 0.01). Global VO2 increased by 17.6% (p < 0.05). Conclusions: The NIRS arterial occlusion method is able to measure changes in peripheral VO2 induced by limb cooling. The changes are more pronounced with moderate limb cooling when a concomitant rise in global VO2 is observed. Change in peripheral temperature must be taken into consideration in the interpretation of peripheral VO2 measurements in neonates. PMID:12598504

Effect of limb cooling on peripheral and global oxygen consumption in neonates.

PubMed

Hassan, I A-A; Wickramasinghe, Y A; Spencer, S A

2003-03-01

To evaluate peripheral oxygen consumption (VO(2)) measurements using near infrared spectroscopy (NIRS) with arterial occlusion in healthy term neonates by studying the effect of limb cooling on peripheral and global VO(2). Twenty two healthy term neonates were studied. Peripheral VO(2) was measured by NIRS using arterial occlusion and measurement of the oxyhaemoglobin (HbO(2)) decrement slope. Global VO(2) was measured by open circuit calorimetry. Global and peripheral VO(2) was measured in each neonate before and after limb cooling. In 10 neonates, a fall in forearm temperature of 2.2 degrees C (mild cooling) decreased forearm VO(2) by 19.6% (p < 0.01). Global VO(2) did not change. In 12 neonates, a fall in forearm temperature of 4 degrees C (moderate cooling) decreased forearm VO(2) by 34.7% (p < 0.01). Global VO(2) increased by 17.6% (p < 0.05). The NIRS arterial occlusion method is able to measure changes in peripheral VO(2) induced by limb cooling. The changes are more pronounced with moderate limb cooling when a concomitant rise in global VO(2) is observed. Change in peripheral temperature must be taken into consideration in the interpretation of peripheral VO(2) measurements in neonates.

Effects of medium on nuclear properties in multifragmentation

NASA Astrophysics Data System (ADS)

De, J. N.; Samaddar, S. K.; Viñas, X.; Centelles, M.; Mishustin, I. N.; Greiner, W.

2012-08-01

In multifragmentation of hot nuclear matter, properties of fragments embedded in a soup of nucleonic gas and other fragments should be modified as compared with isolated nuclei. Such modifications are studied within a simple model where only nucleons and one kind of heavy nuclei are considered. The interaction between different species is described with a momentum-dependent two-body potential whose parameters are fitted to reproduce properties of cold isolated nuclei. The internal energy of heavy fragments is parametrized according to a liquid-drop model with density- and temperature-dependent parameters. Calculations are carried out for several subnuclear densities and moderate temperatures, for isospin-symmetric and asymmetric systems. We find that the fragments get stretched due to interactions with the medium and their binding energies decrease with increasing temperature and density of nuclear matter.

Investigation of room temperature UV emission of ZnO films with different defect densities induced by laser irradiation.

PubMed

Zhao, Yan; Jiang, Yijian

2010-08-01

We studied the room temperature UV emission of ZnO films with different defect densities which is fabricated by KrF laser irradiation process. It is shown room temperature UV photoluminescence of ZnO film is composed of contribution from free-exciton (FX) recombination and its longitudinal-optical phonon replica (FX-LO) (1LO, 2LO). With increase of the defect density, the FX emission decreased and FX-LO emission increased dramatically; and the relative strengths of FX to FX-LO emission intensities determine the peak position and intensity of UV emission. What is more, laser irradiation with moderate energy density could induce the crystalline ZnO film with very flat and smooth surface. This investigation indicates that KrF laser irradiation could effectively modulate the exciton emission and surface morphology, which is important for the application of high performance of UV emitting optoelectronic devices. Copyright 2010 Elsevier B.V. All rights reserved.

The effect of intrinsic crumpling on the mechanics of free-standing graphene

NASA Astrophysics Data System (ADS)

Nicholl, Ryan J. T.; Conley, Hiram J.; Lavrik, Nickolay V.; Vlassiouk, Ivan; Puzyrev, Yevgeniy S.; Sreenivas, Vijayashree Parsi; Pantelides, Sokrates T.; Bolotin, Kirill I.

2015-11-01

Free-standing graphene is inherently crumpled in the out-of-plane direction due to dynamic flexural phonons and static wrinkling. We explore the consequences of this crumpling on the effective mechanical constants of graphene. We develop a sensitive experimental approach to probe stretching of graphene membranes under low applied stress at cryogenic to room temperatures. We find that the in-plane stiffness of graphene is 20-100 N m-1 at room temperature, much smaller than 340 N m-1 (the value expected for flat graphene). Moreover, while the in-plane stiffness only increases moderately when the devices are cooled down to 10 K, it approaches 300 N m-1 when the aspect ratio of graphene membranes is increased. These results indicate that softening of graphene at temperatures <400 K is caused by static wrinkling, with only a small contribution due to flexural phonons. Together, these results explain the large variation in reported mechanical constants of graphene devices and pave the way towards controlling their mechanical properties.

Temperature tuning from direct to inverted bistable electroluminescence in resonant tunneling diodes

NASA Astrophysics Data System (ADS)

Hartmann, F.; Pfenning, A.; Rebello Sousa Dias, M.; Langer, F.; Höfling, S.; Kamp, M.; Worschech, L.; Castelano, L. K.; Marques, G. E.; Lopez-Richard, V.

2017-10-01

We study the electroluminescence (EL) emission of purely n-doped resonant tunneling diodes in a wide temperature range. The paper demonstrates that the EL originates from impact ionization and radiative recombination in the extended collector region of the tunneling device. Bistable current-voltage response and EL are detected and their respective high and low states are tuned under varying temperature. The bistability of the EL intensity can be switched from direct to inverted with respect to the tunneling current and the optical on/off ratio can be enhanced with increasing temperature. One order of magnitude amplification of the optical on/off ratio can be attained compared to the electrical one. Our observation can be explained by an interplay of moderate peak-to-valley current ratios, large resonance voltages, and electron energy loss mechanisms, and thus, could be applied as an alternative route towards optoelectronic applications of tunneling devices.

Reactivity Coefficient Calculation for AP1000 Reactor Using the NODAL3 Code

NASA Astrophysics Data System (ADS)

Pinem, Surian; Malem Sembiring, Tagor; Tukiran; Deswandri; Sunaryo, Geni Rina

2018-02-01

The reactivity coefficient is a very important parameter for inherent safety and stability of nuclear reactors operation. To provide the safety analysis of the reactor, the calculation of changes in reactivity caused by temperature is necessary because it is related to the reactor operation. In this paper, the temperature reactivity coefficients of fuel and moderator of the AP1000 core are calculated, as well as the moderator density and boron concentration. All of these coefficients are calculated at the hot full power condition (HFP). All neutron diffusion constant as a function of temperature, water density and boron concentration were generated by the SRAC2006 code. The core calculations for determination of the reactivity coefficient parameter are done by using NODAL3 code. The calculation results show that the fuel temperature, moderator temperature and boron reactivity coefficients are in the range between -2.613 pcm/°C to -4.657pcm/°C, -1.00518 pcm/°C to 1.00649 pcm/°C and -9.11361 pcm/ppm to -8.0751 pcm/ppm, respectively. For the water density reactivity coefficients, the positive reactivity occurs at the water temperature less than 190 °C. The calculation results show that the reactivity coefficients are accurate because the results have a very good agreement with the design value.

Tropical and Extratropical Cyclone Damages under Climate Change

NASA Astrophysics Data System (ADS)

Ranson, M.; Kousky, C.; Ruth, M.; Jantarasami, L.; Crimmins, A.; Tarquinio, L.

2014-12-01

This paper provides the first quantitative synthesis of the rapidly growing literature on future tropical and extratropical cyclone losses under climate change. We estimate a probability distribution for the predicted impact of changes in global surface air temperatures on future storm damages, using an ensemble of 296 estimates of the temperature-damage relationship from twenty studies. Our analysis produces three main empirical results. First, we find strong but not conclusive support for the hypothesis that climate change will cause damages from tropical cyclones and wind storms to increase, with most models (84 and 92 percent, respectively) predicting higher future storm damages due to climate change. Second, there is substantial variation in projected changes in losses across regions. Potential changes in damages are greatest in the North Atlantic basin, where the multi-model average predicts that a 2.5°C increase in global surface air temperature would cause hurricane damages to increase by 62 percent. The ensemble predictions for Western North Pacific tropical cyclones and European wind storms (extratropical cyclones) are approximately one third of that magnitude. Finally, our analysis shows that existing models of storm damages under climate change generate a wide range of predictions, ranging from moderate decreases to very large increases in losses.

The effects of internal heating and large scale climate variations on tectonic bi-stability in terrestrial planets

NASA Astrophysics Data System (ADS)

Weller, M. B.; Lenardic, A.; O'Neill, C.

2015-06-01

We use 3D mantle convection and planetary tectonics models to explore the links between tectonic regimes and the level of internal heating within the mantle of a planet (a proxy for thermal age), planetary surface temperature, and lithosphere strength. At both high and low values of internal heating, for moderate to high lithospheric yield strength, hot and cold stagnant-lid (single plate planet) states prevail. For intermediate values of internal heating, multiple stable tectonic states can exist. In these regions of parameter space, the specific evolutionary path of the system has a dominant role in determining its tectonic state. For low to moderate lithospheric yield strength, mobile-lid behavior (a plate tectonic-like mode of convection) is attainable for high degrees of internal heating (i.e., early in a planet's thermal evolution). However, this state is sensitive to climate driven changes in surface temperatures. Relatively small increases in surface temperature can be sufficient to usher in a transition from a mobile- to a stagnant-lid regime. Once a stagnant-lid mode is initiated, a return to mobile-lid is not attainable by a reduction of surface temperatures alone. For lower levels of internal heating, the tectonic regime becomes less sensitive to surface temperature changes. Collectively our results indicate that terrestrial planets can alternate between multiple tectonic states over giga-year timescales. Within parameter space regions that allow for bi-stable behavior, any model-based prediction as to the current mode of tectonics is inherently non-unique in the absence of constraints on the geologic and climatic histories of a planet.

Synergistic chemotherapy by combined moderate hyperthermia and photochemical internalization

PubMed Central

Christie, Catherine; Molina, Stephanie; Gonzales, Jonathan; Berg, Kristian; Nair, Rohit Kumar; Huynh, Khoi; Madsen, Steen J.; Hirschberg, Henry

2016-01-01

Combination therapies of photochemical internalization (PCI) and moderate hyperthermia (MHT) were investigated in an in vitro system consisting of human and rat glioma spheroids. PCI using the amphiphilic photosensitizer, AlPcS2a and two anti cancer agents BLM or 5-FU were used. Spheroids were irradiated with λ = 670 nm laser light in an incubator at temperatures ranging from 37 to 44°C. For each temperature investigated, spheroids were divided into 4 groups: control, drug-only, photodynamic therapy (PDT), and PCI. PDT and PCI spheroids were exposed to radiant exposures ranging from 0.3 to 2.5 J cm−2 using an irradiance of 5 mW cm−2. Toxicity was evaluated from spheroid growth kinetics. The combination of PCI and MHT resulted in significant increases in BLM efficacy at 44°C for both cell line derived spheroids compared to controls at 37°C over the range of radiant exposures examined. 5-FU PCI was ineffective for the human cell line at both 37 and 44°C. PMID:27446650

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.

Effect of dietary astaxanthin on the growth performance, non-specific immunity, and antioxidant capacity of pufferfish (Takifugu obscurus) under high temperature stress.

PubMed

Cheng, Chang-Hong; Guo, Zhi-Xun; Ye, Chao-Xia; Wang, An-Li

2018-02-01

The present study was conducted to investigate the effects of astaxanthin on growth performance, biochemical parameters, ROS production, and immune-related gene expressions of the pufferfish (Takifugu obscurus) under high temperature stress. The experimental basal diets supplemented with astaxanthin at the rates of 0 (control), 20, 40, 80, 160, and 320 mg kg -1 were fed to fish for 8 weeks. The results showed that the fish fed diet with 80, 160, and 320 mg kg -1 astaxanthin significantly improved weight gain and specific growth rate. Furthermore, fish fed the moderate dietary astaxanthin increased plasma alkaline phosphatase activities, and decrease plasma aspartate aminotransferase and alanine aminotransferase activities. After the feeding trial, the fish were exposed to high temperature stress for 48 h. The results shown that astaxanthin could suppress ROS production induced by high temperature stress. Meanwhile, compared with the control group, the astaxanthin groups increased SOD, CAT, and HSP70 mRNA levels under high temperature stress. These results showed that the basal diet supplemented with 80-320 mg kg -1 astaxanthin could enhance growth, nonspecific immune responses, and antioxidant defense system and improve resistance against high temperature stress in pufferfish.

In situ Raman and X-ray diffraction studies on the high pressure and temperature stability of methane hydrate up to 55 GPa.

PubMed

Kadobayashi, Hirokazu; Hirai, Hisako; Ohfuji, Hiroaki; Ohtake, Michika; Yamamoto, Yoshitaka

2018-04-28

High-temperature and high-pressure experiments were performed under 2-55 GPa and 298-653 K using in situ Raman spectroscopy and X-ray diffraction combined with externally heated diamond anvil cells to investigate the stability of methane hydrate. Prior to in situ experiments, the typical C-H vibration modes of methane hydrate and their pressure dependence were measured at room temperature using Raman spectroscopy to make a clear discrimination between methane hydrate and solid methane which forms through the decomposition of methane hydrate at high temperature. The sequential in situ Raman spectroscopy and X-ray diffraction revealed that methane hydrate survives up to 633 K and 40.3 GPa and then decomposes into solid methane and ice VII above the conditions. The decomposition curve of methane hydrate estimated by the present experiments is >200 K lower than the melting curves of solid methane and ice VII, and moderately increases with increasing pressure. Our result suggests that although methane hydrate may be an important candidate for major constituents of cool exoplanets and other icy bodies, it is unlikely to be present in the ice mantle of Neptune and Uranus, where the temperature is expected to be far beyond the decomposition temperatures.

In situ Raman and X-ray diffraction studies on the high pressure and temperature stability of methane hydrate up to 55 GPa

NASA Astrophysics Data System (ADS)

Kadobayashi, Hirokazu; Hirai, Hisako; Ohfuji, Hiroaki; Ohtake, Michika; Yamamoto, Yoshitaka

2018-04-01

High-temperature and high-pressure experiments were performed under 2-55 GPa and 298-653 K using in situ Raman spectroscopy and X-ray diffraction combined with externally heated diamond anvil cells to investigate the stability of methane hydrate. Prior to in situ experiments, the typical C-H vibration modes of methane hydrate and their pressure dependence were measured at room temperature using Raman spectroscopy to make a clear discrimination between methane hydrate and solid methane which forms through the decomposition of methane hydrate at high temperature. The sequential in situ Raman spectroscopy and X-ray diffraction revealed that methane hydrate survives up to 633 K and 40.3 GPa and then decomposes into solid methane and ice VII above the conditions. The decomposition curve of methane hydrate estimated by the present experiments is >200 K lower than the melting curves of solid methane and ice VII, and moderately increases with increasing pressure. Our result suggests that although methane hydrate may be an important candidate for major constituents of cool exoplanets and other icy bodies, it is unlikely to be present in the ice mantle of Neptune and Uranus, where the temperature is expected to be far beyond the decomposition temperatures.

Temperature regulation and metabolism of an Australian bat, Chalinolobus gouldii (Chiroptera:Vespertilionidae) when euthermic and torpid.

PubMed

Hosken, D J; Withers, P C

1997-01-01

The thermal and metabolic physiology of Chalinolobus gouldii, an Australian vespertilionid bat, was studied in the laboratory using flow-through respirometry. Chalinolobus gouldii exhibits a clear pattern of euthermic thermoregulation, typical of endotherms with respect to body temperature and rate of oxygen consumption. The basal metabolic rate of euthermic Chalinolobus gouldii is approximately 86% of that predicted for a 17.5-g mammal and falls into the range of mass-specific basal metabolic rates ascribed to vespertilionid bats. However, like most vespertilionid bats, Chalinolobus gouldii displays extreme thermolability. It is able to enter into torpor and spontaneously arouse at ambient temperatures as low as 5 degrees C. Torpid bats thermoconform at moderate ambient temperature, with body temperature approximately ambient temperature, and have a low rate of oxygen consumption determined primarily by Q10 effects. At low ambient temperature (< 10 degrees C), torpid C. gouldii begin to regulate their body temperature by increased metabolic heat production; they tend to maintain a higher body temperature at low ambient temperature than do many northern hemisphere hibernating bats. Use of torpor leads to significant energy savings. The evaporative water loss of euthermic bats is relatively high, which seems unusual for a bat whose range includes extremely arid areas of Australia, and is reduced during torpor. The thermal conductance of euthermic C. gouldii is less than that predicted for a mammal of its size. The thermal conductance is considerably lower for torpid bats at intermediate body temperature and ambient temperature, but increases to euthermic values for torpid bats when thermoregulating at low ambient temperature.

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.

Calcium addition at the Hubbard Brook Experimental Forest increases the capacity for stress tolerance and carbon capture in red spruce (Picea rubens) trees during the cold season

Treesearch

Paul G. Schaberg; Rakesh Minocha; Stephanie Long; Joshua M. Halman; Gary J. Hawley; Christopher Eagar

2011-01-01

Red spruce (Picea rubens Sarg.) trees are uniquely vulnerable to foliar freezing injury during the cold season (fall and winter), but are also capable of photosynthetic activity if temperatures moderate. To evaluate the influence of calcium (Ca) addition on the physiology of red spruce during the cold season, we measured concentrations of foliar...

COATING COLUMBIUM FOR HIGH TEMPERATURES

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

Sandoz, G.

1960-04-01

An investigation was conducted to find a coating for niobium to make it oxidation resistaat. The results obtained at the U. S. Naval Research Laboratory using zinc as a coating are reported. Tests conducted on molten zinc dipped niobium with an intentional flaw after coating, revealed a moderate hardness increase near the flaw. No indication of oxygen absorption or other embrittlement after 5 hours at 2000 deg F was observed in the coated metal. (B.O.G.)

Microbial Community Structure and Dynamics of Dark Fire-Cured Tobacco Fermentation▿ †

PubMed Central

Di Giacomo, Michele; Paolino, Marianna; Silvestro, Daniele; Vigliotta, Giovanni; Imperi, Francesco; Visca, Paolo; Alifano, Pietro; Parente, Dino

2007-01-01

The Italian Toscano cigar production includes a fermentation step that starts when dark fire-cured tobacco leaves are moistened and mixed with ca. 20% prefermented tobacco to form a 500-kg bulk. The dynamics of the process, lasting ca. 18 days, has never been investigated in detail, and limited information is available on microbiota involved. Here we show that Toscano fermentation is invariably associated with the following: (i) an increase in temperature, pH, and total microbial population; (ii) a decrease in reducing sugars, citric and malic acids, and nitrate content; and (iii) an increase in oxalic acid, nitrite, and tobacco-specific nitrosamine content. The microbial community structure and dynamics were investigated by culture-based and culture-independent approaches, including denaturing gradient gel electrophoresis and single-strand conformational polymorphism. Results demonstrate that fermentation is assisted by a complex microbial community, changing in structure and composition during the process. During the early phase, the moderately acidic and mesophilic environment supports the rapid growth of a yeast population predominated by Debaryomyces hansenii. At this stage, Staphylococcaceae (Jeotgalicoccus and Staphylococcus) and Lactobacillales (Aerococcus, Lactobacillus, and Weissella) are the most commonly detected bacteria. When temperature and pH increase, endospore-forming low-G+C content gram-positive bacilli (Bacillus spp.) become evident. This leads to a further pH increase and promotes growth of moderately halotolerant and alkaliphilic Actinomycetales (Corynebacterium and Yania) during the late phase. To postulate a functional role for individual microbial species assisting the fermentation process, a preliminary physiological and biochemical characterization of representative isolates was performed. PMID:17142368

[Effects of snow pack on soil nitrogen transformation enzyme activities in a subalpine Abies faxioniana forest of western Sichuan, China].

PubMed

Xiong, Li; Xu, Zhen-Feng; Wu, Fu-Zhong; Yang, Wan-Qin; Yin, Rui; Li, Zhi-Ping; Gou, Xiao-Lin; Tang, Shi-Shan

2014-05-01

This study characterized the dynamics of the activities of urease, nitrate reductase and nitrite reductase in both soil organic layer and mineral soil layer under three depths of snow pack (deep snowpack, moderate snowpack and shallow snowpack) over the three critical periods (snow formed period, snow stable period, and snow melt period) in the subalpine Abies faxoniana forest of western Sichuan in the winter of 2012 and 2013. Throughout the winter, soil temperature under deep snowpack increased by 46.2% and 26.2%, respectively in comparison with moderate snowpack and shallow snowpack. In general, the three nitrogen-related soil enzyme activities under shallow snowpack were 0.8 to 3.9 times of those under deep snowpack during the winter. In the beginning and thawing periods of seasonal snow pack, shallow snowpack significantly increased the activities of urease, nitrate and nitrite reductase enzyme in both soil organic layer and mineral soil layer. Although the activities of the studied enzymes in soil organic layer and mineral soil layer were observed to be higher than those under deep- and moderate snowpacks in deep winter, no significant difference was found under the three snow packs. Meanwhile, the effects of snowpack on the activities of the measured enzymes were related with season, soil layer and enzyme type. Significant variations of the activities of nitrogen-related enzymes were found in three critical periods over the winter, and the three measured soil enzymes were significantly higher in organic layer than in mineral layer. In addition, the activities of the three measured soil enzymes were closely related with temperature and moisture in soils. In conclusion, the decrease of snow pack induced by winter warming might increase the activities of soil enzymes related with nitrogen transformation and further stimulate the process of wintertime nitrogen transformation in soils of the subalpine forest.

Misoprostol dose-related shivering and pyrexia in the third stage of labour. WHO Collaborative Trial of Misoprostol in the Management of the Third Stage of Labour.

PubMed

Lumbiganon, P; Hofmeyr, J; Gülmezoglu, A M; Pinol, A; Villar, J

1999-04-01

To select the misoprostol dose to be used in a large multicentre randomised trial comparing misoprostol with oxytocin in the routine management of the third stage of labour. Randomised pilot trial, double-blinded with the use of double placebos. Two of the nine hospitals that will participate in the main multicentre trial. The hospitals were located in Johannesburg, South Africa and Khon Kaen, Thailand. Women during second stage of labour about to be delivered vaginally. The trial had three arms: misoprostol 400 microg versus misoprostol 600 microg versus intramuscular oxytocin 10 IU. Each group received an injection and three tablets immediately after the birth of the baby. Shivering and pyrexia rates were the main outcome measures. Data on other side effects and characteristics of the third stage of labour were also collected. Side effects were noted as none, mild, moderate or severe. Both shivering and pyrexia (temperature > 38 degrees C) were most common in the 600 microg misoprostol group (28% and 7.5% for shivering and pyrexia, respectively) compared with 400 microg misoprostol (19% and 2%), and the oxytocin group (12.5% and 3%). The increase in shivering in the misoprostol 600 microg group was due primarily to a higher rate of moderate shivering. None of the women had a temperature > 40 degrees C. There were no increases in severe side effects and other adverse events in the misoprostol 600 microg group. When used in the management of the third stage of labour oral misoprostol is associated with an increase in the rate of moderate shivering and pyrexia which seems to be dose-related. Based on the results of this pilot trial, the Steering Committee has decided to use 600 microg misoprostol in the main trial, comparing it with oxytocin, in order to achieve higher effectiveness.

Satellite-derived, melt-season surface temperature of the Greenland Ice Sheet (2000-2005) and its relationship to mass balance

USGS Publications Warehouse

Hall, D.K.; Williams, R.S.; Casey, K.A.; DiGirolamo, N.E.; Wan, Z.

2006-01-01

Mean, clear-sky surface temperature of the Greenland Ice Sheet was measured for each melt season from 2000 to 2005 using Moderate-Resolution Imaging Spectroradiometer (MODIS)–derived land-surface temperature (LST) data-product maps. During the period of most-active melt, the mean, clear-sky surface temperature of the ice sheet was highest in 2002 (−8.29 ± 5.29°C) and 2005 (−8.29 ± 5.43°C), compared to a 6-year mean of −9.04 ± 5.59°C, in agreement with recent work by other investigators showing unusually extensive melt in 2002 and 2005. Surface-temperature variability shows a correspondence with the dry-snow facies of the ice sheet; a reduction in area of the dry-snow facies would indicate a more-negative mass balance. Surface-temperature variability generally increased during the study period and is most pronounced in the 2005 melt season; this is consistent with surface instability caused by air-temperature fluctuations.

Rainfall simulation experiments: Influence of water temperature, water quality and plot design on soil erosion and runoff

NASA Astrophysics Data System (ADS)

Iserloh, Thomas; Pegoraro, Dominique; Schlösser, Angelika; Thesing, Hannah; Seeger, Manuel; Ries, Johannes B.

2015-04-01

Field rainfall simulators are designed to study soil erosion processes and provide urgently needed data for various geomorphological, hydrological and pedological issues. Due to the different conditions and technologies applied, there are several methodological aspects under review of the scientific community, particularly concerning design, procedures and conditions of measurement for infiltration, runoff and soil erosion. This study aims at contributing fundamental data for understanding rainfall simulations in depth by studying the effect of the following parameters on the measurement results: 1. Plot design - round or rectangular plot: Can we identify differences in amount of runoff and erosion? 2. Water quality: What is the influence of the water's salt load on interrill erosion and infiltration as measured by rainfall experiments? 3. Water temperature: How much are the results conditioned by the temperature of water, which is subject to changes due to environmental conditions during the experiments? Preliminary results show a moderate increase of soil erosion with the water's salt load while runoff stays almost on the same level. With increasing water temperature, runoff increases continuously. At very high temperatures, soil erosion is clearly increased. A first comparison between round and rectangular plot indicates the rectangular plot to be the most suitable plot shape, but ambiguous results make further research necessary. The analysis of these three factors concerning their influence on runoff and erosion shows that clear methodological standards are necessary in order to make rainfall simulation experiments comparable.

Thermoregulation During Spaceflight

NASA Technical Reports Server (NTRS)

Greenleaf, John E.; Fortney, Suzanne M.

1992-01-01

The purpose of this flight proposal is to investigate human thermoregulatory parameters during exercise in microgravity. The hypothesis to be tested is that microgravity-adopted astronauts will exhibit accentuated increases in their core temperature (excess hyperthermia) during exercise because of altered heat loss responses due to reduced sweating and/or accentuated vasodilation. The specific aims are (1) to compare core and skin temperature responses during moderate exercise before flight and inflight; (2) to determine whether the hypothesized inflight excessive hyperthermia is due to increased heat production, reduced, sweating, impaired peripheral vasodilation, or to some combination of these factors; and (3) to determine whether heat production at an exercise load of 60 percent of the maximal working capacity is similar preflight and inflight. It is expected that the astronauts will exhibit excessive hyperthermia during exposure to microgravity which will be caused by decreased sweating and decreased skin blood flow.

Does the hybrid light source (LED/laser) influence temperature variation on the enamel surface during 35% hydrogen peroxide bleaching? A randomized clinical trial.

PubMed

de Freitas, Patricia Moreira; Menezes, Andressa Nery; da Mota, Ana Carolina Costa; Simões, Alyne; Mendes, Fausto Medeiros; Lago, Andrea Dias Neves; Ferreira, Leila Soares; Ramos-Oliveira, Thayanne Monteiro

2016-01-01

The present study investigated how a hybrid light source (LED/laser) influences temperature variation on the enamel surfaces during 35% hydrogen peroxide (HP) bleaching. Effects on the whitening effectiveness and tooth sensitivity were analyzed. Twenty-two volunteers were randomly assigned to two different treatments in a split-mouth experimental model: group 1 (control), 35% HP; group 2 (experimental), 35% HP + LED/laser. Color evaluation was performed before treatment, and 7 and 14 days after completion of bleaching, using a color shade scale. Tooth sensitivity was assessed using a visual analog scale (VAS; before, immediately, and 24 hours after bleaching). During the bleaching treatment, thermocouple channels positioned on the tooth surfaces recorded the temperature. Data on color and temperature changes were subjected to statistical analysis (α = 5%). Tooth sensitivity data were evaluated descriptively. Groups 1 and 2 showed mean temperatures (± standard deviation) of 30.7 ± 1.2 °C and 34.1 ± 1.3 °C, respectively. It was found that there were statistically significant differences between the groups, with group 2 showing higher mean variation (P < .0001). The highest temperature variation occurred for group 2, with an increase of 5.3 °C at the enamel surface. The color change results showed no differences in bleaching between the two treatment groups (P = .177). The variation of the average temperature during the treatments was not statistically associated with color variation (P = .079). Immediately after bleaching, it was found that 36.4% of the subjects in group 2 had mild to moderate sensitivity. In group 1, 45.5% showed moderate sensitivity. In both groups, the sensitivity ceased within 24 hours. Hybrid light source (LED/ laser) influences temperature variation on the enamel surface during 35% HP bleaching and is not related to greater tooth sensitivity.

Whole-body pre-cooling and heat storage during self-paced cycling performance in warm humid conditions.

PubMed

Kay, D; Taaffe, D R; Marino, F E

1999-12-01

The aim of this study was to establish the effect that pre-cooling the skin without a concomitant reduction in core temperature has on subsequent self-paced cycling performance under warm humid (31 degrees C and 60% relative humidity) conditions. Seven moderately trained males performed a 30 min self-paced cycling trial on two separate occasions. The conditions were counterbalanced as control or whole-body pre-cooling by water immersion so that resting skin temperature was reduced by approximately 5-6 degrees C. After pre-cooling, mean skin temperature was lower throughout exercise and rectal temperature was lower (P < 0.05) between 15 and 25 min of exercise. Consequently, heat storage increased (P < 0.003) from 84.0+/-8.8 W x m(-2) to 153+/-13.1 W x m(-2) (mean +/- s(mean)) after pre-cooling, while total body sweat fell from 1.7+/-0.1 l x h(-1) to 1.2+/-0.1 l h(-1) (P < 0.05). The distance cycled increased from 14.9+/-0.8 to 15.8+/-0.7 km (P < 0.05) after pre-cooling. The results indicate that skin pre-cooling in the absence of a reduced rectal temperature is effective in reducing thermal strain and increasing the distance cycled in 30 min under warm humid conditions.

Effect of temperature on removal of trace organic chemicals in managed aquifer recharge systems.

PubMed

Alidina, Mazahirali; Shewchuk, Justin; Drewes, Jörg E

2015-03-01

This study was undertaken to investigate whether changes in temperature experienced in MAR systems affect attenuation of trace organic chemicals (TOrCs). A set of laboratory-scale soil columns were placed in a temperature-controlled environmental chamber and operated at five different temperature set-points (30, 20, 10, 8 and 4°C) covering the range of typical groundwater temperatures in cold, moderate and arid climate regions. Removal of bulk organic carbon both in the infiltration zone as well as during deeper infiltration was independent of temperature. Of the 22 TOrCs investigated, only six chemicals exhibited changes in attenuation as a function of temperature. Attenuation of four of the compounds (diclofenac, gemfibrozil, ketoprofen and naproxen) decreased as the temperature was reduced from 30°C to 4°C, likely due to decreased microbial activity at lower temperatures. As the temperature was decreased, however, attenuation of oxybenzone and trimethoprim were noted to increase. This increased attenuation was likely due to more efficient sorption at lower temperatures, though possible changes in the microbial composition as the temperature decreased may also have contributed to this change. Changes in rate constants of attenuation (ka) for the biotransformed TOrCs with temperature suggested the existence of a critical temperature at 10°C for three of the four TOrCs, where significant changes to rates of attenuation occurred. Results from this study indicated that for most TOrCs, changes in temperature do not impact their attenuation. Thus, seasonal changes in temperature are not considered to be a major concern for attenuation of most TOrCs in MAR systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Interaction between muscle temperature and contraction velocity affects mechanical efficiency during moderate-intensity cycling exercise in young and older women.

PubMed

Bell, Martin P; Ferguson, Richard A

2009-09-01

The effect of elevated muscle temperature on mechanical efficiency was investigated during exercise at different pedal frequencies in young and older women. Eight young (24 +/- 3 yr) and eight older (70 +/- 4 yr) women performed 6-min periods of cycling at 75% ventilatory threshold at pedal frequencies of 45, 60, 75, and 90 rpm under control and passively elevated local muscle temperature conditions. Mechanical efficiency was calculated from the ratio of energy turnover (pulmonary O(2) uptake) and mechanical power output. Overall, elevating muscle temperature increased (P < 0.05) mechanical efficiency in young (32.0 +/- 3.1 to 34.0 +/- 5.5%) and decreased (P < 0.05) efficiency in older women (30.2 +/- 5.6 to 27.9 +/- 4.1%). The different effect of elevated muscle temperature in young and older women reflects a shift in the efficiency-velocity relationship of skeletal muscle. These effects may be due to differences in recruitment patterns, as well as sarcopenic and fiber-type changes with age.

Differential effects of dopamine and opioid receptor blockade on motivated Coca-Cola drinking behavior and associated changes in brain, skin and muscle temperatures.

PubMed

Kiyatkin, E A

2010-05-05

Although pharmacological blockade of both dopamine (DA) and opiate receptors has an inhibiting effect on appetitive motivated behaviors, it is still unclear which physiological mechanisms affected by these treatments underlie the behavioral deficit. To clarify this issue, we examined how pharmacological blockade of either DA (SCH23390+eticlopride at 0.2 mg/kg each) or opioid receptors (naloxone 1 mg/kg) affects motor activity and temperature fluctuations in the nucleus accumbens (NAcc), temporal muscle, and facial skin associated with motivated Coca-Cola drinking behavior in rats. In drug-free conditions, presentation of a cup containing 5 ml of Coca-Cola induced locomotor activation and rapid NAcc temperature increases, which both transiently decreased during drinking, and phasically increased again after the cup was emptied. Muscle temperatures followed this pattern, but increases were weaker and more delayed than those in the NAcc. Skin temperature rapidly dropped after cup presentation, remained at low levels during consumption, and slowly restored during post-consumption behavioral activation. By itself, DA receptor blockade induced robust decrease in spontaneous locomotion, moderate increases in brain and muscle temperatures, and a relative increase in skin temperatures, suggesting metabolic activation coupled with adynamia. Following this treatment (approximately 180 min), motor activation to cup presentation and Coca-Cola consumption were absent, but rats showed NAcc and muscle temperature increases following cup presentation comparable to control. Therefore, DA receptor blockade does not affect significantly central and peripheral autonomic responses to appetitive stimuli, but eliminates their behavior-activating effects, thus disrupting appetitive behavior and blocking consumption. Naloxone alone slightly decreased brain and muscle temperatures and increased skin temperatures, pointing at the enhanced heat loss and possible minor inhibition of basal metabolic activity. This treatment (approximately 60 min) had minimal effects on the latencies of drinking, but increased its total duration, with licking interrupted by pauses and retreats. This behavioral attenuation was coupled with weaker than in control locomotor activation and diminished temperature fluctuations in each recording location. Therefore, attenuation of normal behavioral and physiological responses to appetitive stimuli appears to underlie modest inhibiting effects of opiate receptor blockade on motivated behavior and consumption. (c) 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

Effects of Domestic Storage and Thawing Practices on Salmonella in Poultry-Based Meat Preparations.

PubMed

Roccato, Anna; Uyttendaele, Mieke; Cibin, Veronica; Barrucci, Federica; Cappa, Veronica; Zavagnin, Paola; Longo, Alessandra; Catellani, Paolo; Ricci, Antonia

2015-12-01

Among consumer food handling practices, time-temperature abuse has been reported as one of the most common contributory factors in salmonellosis outbreaks where the evidence is strong. The present study performed storage tests of burgers, sausages, and kebabs and investigated (i) the effect of refrigerator temperatures (4°C versus 8 or 12°C, which were the temperatures recorded in 33 and 3%, respectively, of domestic refrigerators in Italy), with or without prior temperature abuse (25°C for 2 h, simulating transport of meats from shop to home), and (ii) the impact of the thawing method (overnight in the refrigerator at 8°C versus on the kitchen countertop at 23°C) on the presence and numbers of Salmonella bacteria. Storage tests were carried out on naturally or artificially (Salmonella enterica serovar Typhimurium at ca. 10 CFU/g) contaminated products, while freezing-thawing tests were conducted only on artificially contaminated products (Salmonella Typhimurium at ca. 10, 100, and 1,000 CFU/g). The results from the artificially contaminated products showed significant (P < 0.05) growth of Salmonella Typhimurium at 12°C (i.e., from ca. 8 most probable number [MPN]/g to > 710 MPN/g) in kebabs after 7 and 10 days but more moderate growth in sausages (i.e., from ca. 14 MPN/g to a maximum of 96 MPN/g after 9 days of storage). Storage of naturally contaminated burgers or sausages (contamination at or below 1 MPN/g) at 4, 8, or 12°C and a short time of temperature abuse (2 h at 25°C) did not facilitate an increase in the presence and numbers of Salmonella bacteria. Thawing overnight in the refrigerator led to either a moderate reduction or no change of Salmonella Typhimurium numbers in burgers, sausages, and kebabs. Overall, this study showed that domestic storage and thawing practices can affect food safety and that time-temperature abuse can cause a substantial increase of Salmonella numbers in some types of poultry-based meat preparations, highlighting that efforts for the dissemination of consumer guidelines on the correct storage and handling of meats need to be continued.

Decadal analysis of impact of future climate on wheat production in dry Mediterranean environment: A case of Jordan.

PubMed

Dixit, Prakash N; Telleria, Roberto; Al Khatib, Amal N; Allouzi, Siham F

2018-01-01

Different aspects of climate change, such as increased temperature, changed rainfall and higher atmospheric CO 2 concentration, all have different effects on crop yields. Process-based crop models are the most widely used tools for estimating future crop yield responses to climate change. We applied APSIM crop simulation model in a dry Mediterranean climate with Jordan as sentinel site to assess impact of climate change on wheat production at decadal level considering two climate change scenarios of representative concentration pathways (RCP) viz., RCP4.5 and RCP8.5. Impact of climatic variables alone was negative on grain yield but this adverse effect was negated when elevated atmospheric CO 2 concentrations were also considered in the simulations. Crop cycle of wheat was reduced by a fortnight for RCP4.5 scenario and by a month for RCP8.5 scenario at the approach of end of the century. On an average, a grain yield increase of 5 to 11% in near future i.e., 2010s-2030s decades, 12 to 16% in mid future i.e., 2040s-2060s decades and 9 to 16% in end of century period can be expected for moderate climate change scenario (RCP4.5) and 6 to 15% in near future, 13 to 19% in mid future and 7 to 20% increase in end of century period for a drastic climate change scenario (RCP8.5) based on different soils. Positive impact of elevated CO 2 is more pronounced in soils with lower water holding capacity with moderate increase in temperatures. Elevated CO 2 had greater positive effect on transpiration use efficiency (TUE) than negative effect of elevated mean temperatures. The change in TUE was in near perfect direct relationship with elevated CO 2 levels (R 2 >0.99) and every 100-ppm atmospheric CO 2 increase resulted in TUE increase by 2kgha -1 mm -1 . Thereby, in this environment yield gains are expected in future and farmers can benefit from growing wheat. Copyright © 2017 Elsevier B.V. All rights reserved.

Temperature and pressure adaptation of a sulfate reducer from the deep subsurface

PubMed Central

Fichtel, Katja; Logemann, Jörn; Fichtel, Jörg; Rullkötter, Jürgen; Cypionka, Heribert; Engelen, Bert

2015-01-01

Microbial life in deep marine subsurface faces increasing temperatures and hydrostatic pressure with depth. In this study, we have examined growth characteristics and temperature-related adaptation of the Desulfovibrio indonesiensis strain P23 to the in situ pressure of 30 MPa. The strain originates from the deep subsurface of the eastern flank of the Juan de Fuca Ridge (IODP Site U1301). The organism was isolated at 20°C and atmospheric pressure from ~61°C-warm sediments approximately 5 m above the sediment–basement interface. In comparison to standard laboratory conditions (20°C and 0.1 MPa), faster growth was recorded when incubated at in situ pressure and high temperature (45°C), while cell filamentation was induced by further compression. The maximum growth temperature shifted from 48°C at atmospheric pressure to 50°C under high-pressure conditions. Complementary cellular lipid analyses revealed a two-step response of membrane viscosity to increasing temperature with an exchange of unsaturated by saturated fatty acids and subsequent change from branched to unbranched alkyl moieties. While temperature had a stronger effect on the degree of fatty acid saturation and restructuring of main phospholipids, pressure mainly affected branching and length of side chains. The simultaneous decrease of temperature and pressure to ambient laboratory conditions allowed the cultivation of our moderately thermophilic strain. This may in turn be one key to a successful isolation of microorganisms from the deep subsurface adapted to high temperature and pressure. PMID:26500624

The effects of digestion temperature and temperature shock on the biogas yields from the mesophilic anaerobic digestion of swine manure.

PubMed

Chae, K J; Jang, Am; Yim, S K; Kim, In S

2008-01-01

In order to obtain basic design criteria for anaerobic digesters of swine manure, the effects of different digesting temperatures, temperature shocks and feed loads, on the biogas yields and methane content were evaluated. The digester temperatures were set at 25, 30 and 35 degrees C, with four feed loads of 5%, 10%, 20% and 40% (feed volume/digester volume). At a temperature of 30 degrees C, the methane yield was reduced by only 3% compared to 35 degrees C, while a 17.4% reduction was observed when the digestion was performed at 25 degrees C. Ultimate methane yields of 327, 389 and 403 mL CH(4)/g VS(added) were obtained at 25, 30 and 35 degrees C, respectively; with moderate feed loads from 5% to 20% (V/V). From the elemental analysis of swine manure, the theoretical biogas and methane yields at standard temperature and pressure were 1.12L biogas/g VS(destroyed) and 0.724 L CH(4)/g VS(destroyed), respectively. Also, the methane content increased with increasing digestion temperatures, but only to a small degree. Temperature shocks from 35 to 30 degrees C and again from 30 to 32 degrees C led to a decrease in the biogas production rate, but it rapidly resumed the value of the control reactor. In addition, no lasting damage was observed for the digestion performance, once it had recovered.

A dose-response evaluation of rumen-protected niacin in thermoneutral or heat-stressed lactating Holstein cows.

PubMed

Rungruang, S; Collier, J L; Rhoads, R P; Baumgard, L H; de Veth, M J; Collier, R J

2014-01-01

Twenty-four multiparous high-producing dairy cows (40.0±1.4kg/d) were used in a factorial design to evaluate effects of 2 environments [thermoneutral (TN) and heat stress (HS)] and a dose range of dietary rumen-protected niacin (RPN; 0, 4, 8, or 12g/d) on body temperature, sweating rate, feed intake, water intake, production parameters, and blood niacin concentrations. Temperature-humidity index values during TN never exceeded 68 (stress threshold), whereas temperature-humidity index values during HS were above 68 for 24h/d. The HS environment increased hair coat and skin, rectal, and vaginal temperatures; respiration rate; skin and hair coat evaporative heat loss; and water intake and decreased DMI (3.5kg/d), milk yield (4.1kg/d), 4% fat-corrected milk (2.7kg/d), and milk protein yield (181.7g/d). Sweating rate increased during HS (12.7g/m(2) per h) compared with TN, but this increase was only 10% of that reported in summer-acclimated cattle. Niacin supplementation did not affect sweating rate, dry-matter intake, or milk yield in either environment. Rumen-protected niacin increased plasma and milk niacin concentrations in a linear manner. Heat stress reduced niacin concentration in whole blood (7.86 vs. 6.89μg/mL) but not in milk. Reduced blood niacin concentration was partially corrected by dietary RPN. An interaction existed between dietary RPN and environment; dietary RPN linearly increased water intake in both environments, but the increase was greater during HS conditions. Increasing dietary RPN did not influence skin temperatures. During TN, supplementing 12g/d of RPN increased hair coat (unshaved skin; 30.3 vs. 31.3°C at 1600h) but not shaved skin (32.8 vs. 32.9°C at 1600h) temperature when compared with 0g/d at all time points, whereas the maximum temperature (18°C) of the room was lower than skin temperature. These data suggest that dietary RPN increased water intake during both TN and HS and hair coat temperature during TN; however, core body temperature was unaffected. Thus, encapsulated niacin did not improve thermotolerance of winter-acclimated lactating dairy cows exposed to moderate thermal stress in Arizona. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Development of Hydroxyl Tagging Velocimetry for Low Velocity Flows

NASA Technical Reports Server (NTRS)

Andre, Matthieu A.; Bardet, Philippe M.; Burns, Ross A.; Danehy, Paul M.

2016-01-01

Hydroxyl tagging velocimetry (HTV) is a molecular tagging technique that relies on the photo-dissociation of water vapor into OH radicals and their subsequent tracking using laser induced fluorescence. Velocities are then obtained from time-of-flight calculations. At ambient temperature in air, the OH species lifetime is relatively short (<50 µs), making it suited for high speed flows. Lifetime and radicals formation increases with temperature, which allows HTV to also probe low-velocity, high-temperature flows or reacting flows such as flames. The present work aims at extending the domain of applicability of HTV, particularly towards low-speed (<10 m/s) and moderate (<500 K) temperature flows. Results are compared to particle image velocimetry (PIV) measurements recorded in identical conditions. Single shot and averaged velocity profiles are obtained in an air jet at room temperature. By modestly raising the temperature (100-200 degC) the OH production increases, resulting in an improvement of the signal-to-noise ratio (SNR). Use of nitrogen - a non-reactive gas with minimal collisional quenching - extends the OH species lifetime (to over 500 µs), which allows probing of slower flows or, alternately, increases the measurement precision at the expense of spatial resolution. Instantaneous velocity profiles are resolved in a 100degC nitrogen jet (maximum jet-center velocity of 6.5 m/s) with an uncertainty down to 0.10 m/s (1.5%) at 68% confidence level. MTV measurements are compared with particle image velocimetry and show agreement within 2%.

Effect of Fe substitution on the structural, magnetic and electron-transport properties of half-metallic Co 2TiSi

DOE PAGES

Jin, Y.; Waybright, J.; Kharel, P.; ...

2017-01-11

The structural, magnetic and electron-transport properties of Co 2Ti 1-xFe xSi (x = 0, 0.25, 0.5) ribbons prepared by arc-melting and melt-spinning were investigated. The rapidly quenched Co 2Ti 0.5Fe 0.5Si crystallized in the cubic L2 1 structure whereas Co 2Ti 0.75Fe 0.25Si and Co 2TiFe 0Si showed various degrees of B2-type disorder. At room temperature, all the samples are ferromagnetic, and the Curie temperature increased from 360 K for Co 2TiSi to about 800 K for Co 2Ti 0.5Fe 0.5Si. The measured magnetization also increased due to partial substitution of Fe for Ti atoms. The ribbons are moderately conductingmore » and show positive temperature coefficient of resistivity with the room temperature resistivity being between 360 μΩcm and 440 μΩcm. The experimentally observed structural and magnetic properties are consistent with the results of first-principle calculations. Our calculations also indicate that the Co 2Ti 1-xFe xSi compound remains nearly half-metallic for x ≤ 0.5. In conclusion, the predicted large band gaps and high Curie temperatures much above room temperature make these materials promising for room temperature spintronic and magnetic applications.« less

Altitude Performance of Modified J71 Afterburner with Revised Engine Operating Conditions

NASA Technical Reports Server (NTRS)

Useller, James W.; Russey, Robert E.

1955-01-01

An investigation was conducted in an altitude test chamber at the NACA Lewis laboratory to determine the effect of a revision of the rated engine operating conditions and modifications to the afterburner fue1 system, flameholder, and shell cooling on the augmented performance of the J71-A-2 (x-29) turbo jet engine operating at altitude . The afterburner modifications were made by the manufacturer to improve the endurance at sea-level, high-pressure conditions and to reduce the afterburner shell temperatures. The engine operating conditions of rated rotational speed and turbine-outlet gas temperature were increased. Data were obtained at conditions simulating flight at a Mach number of 0.9 and at altitudes from 40,000 to 60,000 feet. The afterburner modifications caused a reduction in afterburner combustion efficiency. The increase in rated engine speed and turbine-outlet temperature coupled with the afterburner modifications resulted in the over-all thrust of the engine and afterburner being unchanged at a given afterburner equivalence ratio, while the specific fuel consumption was increased slightly. A moderate shift in the range of equivalence ratios over which the afterburner would operate was encountered, but the maximum operable altitude remained unaltered. The afterburner-shell temperatures were also slightly reduced because of the modifications to the afterburner.

Modeling Air Temperature/Water Temperature Relations Along a Small Mountain Stream Under Increasing Urban Influence

NASA Astrophysics Data System (ADS)

Fedders, E. R.; Anderson, W. P., Jr.; Hengst, A. M.; Gu, C.

2017-12-01

Boone Creek is a headwater stream of low to moderate gradient located in Boone, North Carolina, USA. Total impervious surface coverage in the 5.2 km2 catchment drained by the 1.9 km study reach increases from 13.4% in the upstream half of the reach to 24.3% in the downstream half. Other markers of urbanization, including culverting, lack of riparian shade vegetation, and bank armoring also increase downstream. Previous studies have shown the stream to be prone to temperature surges on short timescales (minutes to hours) caused by summer runoff from the urban hardscaping. This study investigates the effects of urbanization on the stream's thermal regime at daily to yearly timescales. To do this, we developed an analytical model of daily average stream temperatures based on daily average air temperatures. We utilized a two-part model comprising annual and biannual components and a daily component consisting of a 3rd-order Markov process in order to fit the thermal dynamics of our small, gaining stream. Optimizing this model at each of our study sites in each studied year (78 total site-years of data) yielded annual thermal exchange coefficients (K) for each site. These K values quantify the strength of the relationship between stream and air temperature, or inverse thermal stability. In a uniform, pristine catchment environment, K values are expected to decrease downstream as the stream gains discharge volume and, therefore, thermal inertia. Interannual average K values for our study reach, however, show an overall increase from 0.112 furthest upstream to 0.149 furthest downstream, despite a near doubling of stream discharge between these monitoring points. K values increase only slightly in the upstream, less urban, half of the reach. A line of best fit through these points on a plot of reach distance versus K value has a slope of 2E-6. But the K values of downstream, more urbanized sites increase at a rate of 2E-5 per meter of reach distance, an order of magnitude greater. This indicates a possible tipping point in the stream temperature-water temperature relationship at which increased urbanization overpowers increasing stream thermal inertia.

Complex Physiological Response of Norway Spruce to Atmospheric Pollution - Decreased Carbon Isotope Discrimination and Unchanged Tree Biomass Increment.

PubMed

Čada, Vojtěch; Šantrůčková, Hana; Šantrůček, Jiří; Kubištová, Lenka; Seedre, Meelis; Svoboda, Miroslav

2016-01-01

Atmospheric pollution critically affects forest ecosystems around the world by directly impacting the assimilation apparatus of trees and indirectly by altering soil conditions, which subsequently also leads to changes in carbon cycling. To evaluate the extent of the physiological effect of moderate level sulfate and reactive nitrogen acidic deposition, we performed a retrospective dendrochronological analysis of several physiological parameters derived from periodic measurements of carbon stable isotope composition ((13)C discrimination, intercellular CO2 concentration and intrinsic water use efficiency) and annual diameter increments (tree biomass increment, its inter-annual variability and correlation with temperature, cloud cover, precipitation and Palmer drought severity index). The analysis was performed in two mountain Norway spruce (Picea abies) stands of the Bohemian Forest (Czech Republic, central Europe), where moderate levels of pollution peaked in the 1970s and 1980s and no evident impact on tree growth or link to mortality has been reported. The significant influence of pollution on trees was expressed most sensitively by a 1.88‰ reduction of carbon isotope discrimination (Δ(13)C). The effects of atmospheric pollution interacted with increasing atmospheric CO2 concentration and temperature. As a result, we observed no change in intercellular CO2 concentrations (Ci), an abrupt increase in water use efficiency (iWUE) and no change in biomass increment, which could also partly result from changes in carbon partitioning (e.g., from below- to above-ground). The biomass increment was significantly related to Δ(13)C on an individual tree level, but the relationship was lost during the pollution period. We suggest that this was caused by a shift from the dominant influence of the photosynthetic rate to stomatal conductance on Δ(13)C during the pollution period. Using biomass increment-climate correlation analyses, we did not identify any clear pollution-related change in water stress or photosynthetic limitation (since biomass increment did not become more sensitive to drought/precipitation or temperature/cloud cover, respectively). Therefore, we conclude that the direct effect of moderate pollution on stomatal conductance was likely the main driver of the observed physiological changes. This mechanism probably caused weakening of the spruce trees and increased sensitivity to other stressors.

Complex Physiological Response of Norway Spruce to Atmospheric Pollution – Decreased Carbon Isotope Discrimination and Unchanged Tree Biomass Increment

PubMed Central

Čada, Vojtěch; Šantrůčková, Hana; Šantrůček, Jiří; Kubištová, Lenka; Seedre, Meelis; Svoboda, Miroslav

2016-01-01

Atmospheric pollution critically affects forest ecosystems around the world by directly impacting the assimilation apparatus of trees and indirectly by altering soil conditions, which subsequently also leads to changes in carbon cycling. To evaluate the extent of the physiological effect of moderate level sulfate and reactive nitrogen acidic deposition, we performed a retrospective dendrochronological analysis of several physiological parameters derived from periodic measurements of carbon stable isotope composition (13C discrimination, intercellular CO2 concentration and intrinsic water use efficiency) and annual diameter increments (tree biomass increment, its inter-annual variability and correlation with temperature, cloud cover, precipitation and Palmer drought severity index). The analysis was performed in two mountain Norway spruce (Picea abies) stands of the Bohemian Forest (Czech Republic, central Europe), where moderate levels of pollution peaked in the 1970s and 1980s and no evident impact on tree growth or link to mortality has been reported. The significant influence of pollution on trees was expressed most sensitively by a 1.88‰ reduction of carbon isotope discrimination (Δ13C). The effects of atmospheric pollution interacted with increasing atmospheric CO2 concentration and temperature. As a result, we observed no change in intercellular CO2 concentrations (Ci), an abrupt increase in water use efficiency (iWUE) and no change in biomass increment, which could also partly result from changes in carbon partitioning (e.g., from below- to above-ground). The biomass increment was significantly related to Δ13C on an individual tree level, but the relationship was lost during the pollution period. We suggest that this was caused by a shift from the dominant influence of the photosynthetic rate to stomatal conductance on Δ13C during the pollution period. Using biomass increment-climate correlation analyses, we did not identify any clear pollution-related change in water stress or photosynthetic limitation (since biomass increment did not become more sensitive to drought/precipitation or temperature/cloud cover, respectively). Therefore, we conclude that the direct effect of moderate pollution on stomatal conductance was likely the main driver of the observed physiological changes. This mechanism probably caused weakening of the spruce trees and increased sensitivity to other stressors. PMID:27375659

EFFECT OF MODERATE DOSES OF GAMMA RADIATION ON THE KEEPING QUALITY OF BILBERRIES (VACCINIUM MYRTILLUS)

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

Horubala, A.; Pijanowski, E.

1961-01-01

Three batches of bilberries (European blueberries) in small polythene bags were treated with various doses of gamma radiation and kept afterwards either at ambient or cool storage temperatures for about 10 to 25 days. The dose of about 0.3 Mrad caused the destruction of somewhat more than 99% of the original microflora (bacteria, yeasts and moulds) and thus increased by 250 to 300% the storage life of berries in comparison with untreated fruit. Losses of anthocyanin pigments, vitamin C, and jellifying power were rather small, and the subsequent changes in flavor were practically non existant. The authors recommend the applicationmore » of moderate doses of gamma -rays (about 0.3 Mrad) to exported bilberries prior to their shipment. (auth)« less

Development of a Climate-Data Record (CDR) of the Surface Temperature of the Greenland Ice Sheet

NASA Technical Reports Server (NTRS)

Hall, Dorthy K.; Comiso, Josefino C.; Shuman, Christopher A.; DiGirolamo, Nicolo E.; Stock, Larry V.

2010-01-01

Regional "clear sky" surface temperature increases since the early 1980s in the Arctic, measured using Advanced Very High Resolution Radiometer (AVHRR) infrared data, range from 0.57+/-0.02 deg C to 72+/-0.10 deg C per decade. Arctic warming has important implications for ice-sheet mass balance because much of the periphery of the Greenland Ice Sheet is already near 0 deg C during the melt season, and is thus vulnerable to rapid melting if temperatures continue to increase. An increase in melting of the ice sheet would accelerate sea-level rise, an issue affecting potentially billions of people worldwide. To quantify the ice-surface temperature (IST) of the Greenland Ice Sheet, and to provide an IST dataset of Greenland for modelers that provides uncertainties, we are developing a climate-data record (CDR) of daily "clear-sky" IST of the Greenland Ice Sheet, from 1982 to the present using AVHRR (1982 - present) and Moderate-Resolution Imaging Spectroradiometer (MODIS) data (2000 - present) at a resolution of approximately 5 km. Known issues being addressed in the production of the CDR are: time-series bias caused by cloud cover (surface temperatures can be different under clouds vs. clear areas) and cross-calibration in the overlap period between AVHRR instruments, and between AVHRR and MODIS instruments. Because of uncertainties, mainly due to clouds, time-series of satellite IST do not necessarily correspond with actual surface temperatures. The CDR will be validated by comparing results with automatic-weather station data and with satellite-derived surface-temperature products and biases will be calculated.

Moderately lower temperatures greatly extend the lifespan of Brachionus manjavacas (Rotifera): thermodynamics or gene regulation?

PubMed Central

Johnston, Rachel K.; Snell, Terry W.

2016-01-01

Environmental temperature greatly affects lifespan in a wide variety of animals, but the exact mechanisms underlying this effect are still largely unknown. A moderate temperature decrease from 22°C to 16°C extends the lifespan of the monogonont rotifer Brachionus manjavacas by up to 163%. Thermodynamic effects on metabolism contribute to this increase in longevity, but are not the only cause. When rotifers are exposed to 16°C for four days and then transfered to 22°C, they survive until day 13 at nearly identical rates as rotifers maintained at 16°C continuously. This persistence of the higher survival for nine days after transfer to 22°C suggests that low temperature exposure alters the expression of genes that affect the rate of aging. The relative persistence of the gene regulation effect suggests that it may play an even larger role in slowing aging than the thermodynamic effects. The life extending effects of these short-term low temperature treatments are largest when the exposure happens early in the life cycle, demonstrating the importance of early development. There is no advantage to lowering the temperature below 16°C to 11° or 5°C. Rotifers exposed to 16°C also displayed increased resistance to heat, starvation, oxidative and osmotic stress. Reproductive rates at 16°C were lower than those at 22°C, but because they reproduce longer, there is no significant change in the lifetime fecundity of females. To investigate which genes contribute to these effects, the expression of specific temperature sensing genes was knocked down using RNAi. Of 12 genes tested, RNAi knockdown of four eliminated the survival enhancing effects of the four-day cold treatment: TRP7, forkhead box C, Y-box factor, and ribosomal protein S6. This demonstrates that active gene regulation is an important factor in temperature mediated life extension, and that these particular genes play an integral role in these pathways. As a thermoresponsive sensor, TRP7 may be responsible for triggering the signaling cascade contributing to temperature mediated life extension. The TRP genes may also provide especially promising candidates for targeted gene manipulations or pharmacological interventions capable of mimicking the effects of low temperature exposure. These results support recent theories of aging that claim rate of aging is determined by an actively regulated genetic mechanism rather than an accumulation of molecular damage. PMID:26939542

The temperature response of CO2 assimilation, photochemical activities and rubisco activation in camelina sativa, a potential bioenergy crop with limited capacity for acclimation to heat stress.

USDA-ARS?s Scientific Manuscript database

The temperature optimum of photosynthesis coincides with the average daytime temperature in a species’ native environment. Moderate heat stress occurs when temperatures exceed the optimum, inhibiting photosynthesis and decreasing productivity. In the present study, the temperature response of photos...

Spectral emissivities and optical constants of electromagnetically levitated liquid metals as functions of temperature and wavelength

NASA Technical Reports Server (NTRS)

Krishnan, S.; Hauge, R. H.; Margrave, J. L.

1989-01-01

The development of a noncontact temperature measurement device utilizing rotating analyzer ellipsometry is described. The technique circumvents the necessity of spectral emissivity estimation by direct measurement concomittant with radiance brightness. Using this approach, the optical properties of electromagnetically levitated liquid metals Cu, Ag, Au, Ni, Pd, Pt, and Zr were measured in situ at four wavelengths and up to 600 K superheat in the liquid. The data suggest an increase in the emissivity of the liquid compared with the incandescent solid. The data also show moderate temperature dependence of the spectral emissivity. A few measurements of the optical properties of undercooled liquid metals were also conducted. The data for both solids and liquids show excellent agreement with available values in the literature for the spectral emissivities as well as the optical constants.

Metal-Metal Microfilamentary Composites for High Strength Electrical Conductor Applications, Phase 2

DTIC Science & Technology

1991-08-01

wire. A long pulse, even one of high current. eventually allows the accelerating lower grip assembly to catch up to the extending wire. Generation of...suggeat that the mecanical strengthening is due to the increased dlocation density. The experimental results of Rider and Foxon (12) and the theoretical...matrix. The effect of heat treatment temperatures up to 900’C on the internal structure of Nb filaments is not well defined. Moderately deformed Nb single

The mobility of Nb in rutile-saturated NaCl- and NaF-bearing aqueous fluids from 1–6.5 GPa and 300–800 °C

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

Tanis, Elizabeth A.; Simon, Adam; Tschauner, Oliver

Rutile (TiO 2) is an important host phase for high field strength elements (HFSE) such as Nb in metamorphic and subduction zone environments. The observed depletion of Nb in arc rocks is often explained by the hypothesis that rutile sequesters HFSE in the subducted slab and overlying sediment, and is chemically inert with respect to aqueous fluids evolved during prograde metamorphism in the forearc to subarc environment. However, field observations of exhumed terranes, and experimental studies, indicate that HFSE may be soluble in complex aqueous fluids at high pressure (i.e., >0.5 GPa) and moderate to high temperature (i.e., >300 °C).more » In this study, we investigated experimentally the mobility of Nb in NaCl- and NaF-bearing aqueous fluids in equilibrium with Nb-bearing rutile at pressure-temperature conditions applicable to fluid evolution in arc environments. Niobium concentrations in aqueous fluid at rutile saturation were measured directly by using a hydrothermal diamond-anvil cell (HDAC) and synchrotron X-ray fluorescence (SXRF) at 2.1 to 6.5 GPa and 300-500 °C, and indirectly by performing mass loss experiments in a piston-cylinder (PC) apparatus at similar to 1 GPa and 700-800 °C. The concentration of Nb in a 10 wt% NaCl aqueous fluid increases from 6 to 11 mu g/g as temperature increases from 300 to 500 °C, over a pressure range from 2.1 to 2.8 GPa, consistent with a positive temperature dependence. The concentration of Nb in a 20 wt% NaCl aqueous fluid varies from 55 to 150 mu g/g at 300 to 500 °C, over a pressure range from 1.8 to 6.4 GPa; however, there is no discernible temperature or pressure dependence. Here, the Nb concentration in a 4 wt% NaF-bearing aqueous fluid increases from 180 to 910 mu g/g as temperature increases from 300 to 500 °C over the pressure range 2.1 to 6.5 GPa. The data for the F-bearing fluid indicate that the Nb content of the fluid exhibits a dependence on temperature between 300 and 500 °C at ≥ 2 GPa, but there is no observed dependence on pressure. Together, the data demonstrate that the hydrothermal mobility of Nb is strongly controlled by the composition of the fluid, consistent with published data for Ti. At all experimental conditions, however, the concentration of Nb in the fluid is always lower than coexisting rutile, consistent with a role for rutile in moderating the Nb budget of arc rocks.« less

The mobility of Nb in rutile-saturated NaCl- and NaF-bearing aqueous fluids from 1–6.5 GPa and 300–800 °C

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

Tanis, Elizabeth A.; Simon, Adam; Tschauner, Oliver

Rutile (TiO₂) is an important host phase for high field strength elements (HFSE) such as Nb in metamorphic and subduction zone environments. The observed depletion of Nb in arc rocks is often explained by the hypothesis that rutile sequesters HFSE in the subducted slab and overlying sediment, and is chemically inert with respect to aqueous fluids evolved during prograde metamorphism in the forearc to subarc environment. However, field observations of exhumed terranes, and experimental studies, indicate that HFSE may be soluble in complex aqueous fluids at high pressure (i.e., >0.5 GPa) and moderate to high temperature (i.e., >300 °C). Inmore » this study, we investigated experimentally the mobility of Nb in NaCl- and NaF-bearing aqueous fluids in equilibrium with Nb-bearing rutile at pressure-temperature conditions applicable to fluid evolution in arc environments. Niobium concentrations in aqueous fluid at rutile saturation were measured directly by using a hydrothermal diamond-anvil cell (HDAC) and synchrotron X-ray fluorescence (SXRF) at 2.1 to 6.5 GPa and 300–500 °C, and indirectly by performing mass loss experiments in a piston-cylinder (PC) apparatus at ~1 GPa and 700–800 °C. The concentration of Nb in a 10 wt% NaCl aqueous fluid increases from 6 to 11 μg/g as temperature increases from 300 to 500 °C, over a pressure range from 2.1 to 2.8 GPa, consistent with a positive temperature dependence. The concentration of Nb in a 20 wt% NaCl aqueous fluid varies from 55 to 150 μg/g at 300 to 500 °C, over a pressure range from 1.8 to 6.4 GPa; however, there is no discernible temperature or pressure dependence. The Nb concentration in a 4 wt% NaF-bearing aqueous fluid increases from 180 to 910 μg/g as temperature increases from 300 to 500 °C over the pressure range 2.1 to 6.5 GPa. The data for the F-bearing fluid indicate that the Nb content of the fluid exhibits a dependence on temperature between 300 and 500 °C at ≥2 GPa, but there is no observed dependence on pressure. Together, the data demonstrate that the hydrothermal mobility of Nb is strongly controlled by the composition of the fluid, consistent with published data for Ti. At all experimental conditions, however, the concentration of Nb in the fluid is always lower than coexisting rutile, consistent with a role for rutile in moderating the Nb budget of arc rocks.« less

The mobility of Nb in rutile-saturated NaCl- and NaF-bearing aqueous fluids from 1–6.5 GPa and 300–800 °C

DOE PAGES

Tanis, Elizabeth A.; Simon, Adam; Tschauner, Oliver; ...

2015-07-01

Rutile (TiO 2) is an important host phase for high field strength elements (HFSE) such as Nb in metamorphic and subduction zone environments. The observed depletion of Nb in arc rocks is often explained by the hypothesis that rutile sequesters HFSE in the subducted slab and overlying sediment, and is chemically inert with respect to aqueous fluids evolved during prograde metamorphism in the forearc to subarc environment. However, field observations of exhumed terranes, and experimental studies, indicate that HFSE may be soluble in complex aqueous fluids at high pressure (i.e., >0.5 GPa) and moderate to high temperature (i.e., >300 °C).more » In this study, we investigated experimentally the mobility of Nb in NaCl- and NaF-bearing aqueous fluids in equilibrium with Nb-bearing rutile at pressure-temperature conditions applicable to fluid evolution in arc environments. Niobium concentrations in aqueous fluid at rutile saturation were measured directly by using a hydrothermal diamond-anvil cell (HDAC) and synchrotron X-ray fluorescence (SXRF) at 2.1 to 6.5 GPa and 300-500 °C, and indirectly by performing mass loss experiments in a piston-cylinder (PC) apparatus at similar to 1 GPa and 700-800 °C. The concentration of Nb in a 10 wt% NaCl aqueous fluid increases from 6 to 11 mu g/g as temperature increases from 300 to 500 °C, over a pressure range from 2.1 to 2.8 GPa, consistent with a positive temperature dependence. The concentration of Nb in a 20 wt% NaCl aqueous fluid varies from 55 to 150 mu g/g at 300 to 500 °C, over a pressure range from 1.8 to 6.4 GPa; however, there is no discernible temperature or pressure dependence. Here, the Nb concentration in a 4 wt% NaF-bearing aqueous fluid increases from 180 to 910 mu g/g as temperature increases from 300 to 500 °C over the pressure range 2.1 to 6.5 GPa. The data for the F-bearing fluid indicate that the Nb content of the fluid exhibits a dependence on temperature between 300 and 500 °C at ≥ 2 GPa, but there is no observed dependence on pressure. Together, the data demonstrate that the hydrothermal mobility of Nb is strongly controlled by the composition of the fluid, consistent with published data for Ti. At all experimental conditions, however, the concentration of Nb in the fluid is always lower than coexisting rutile, consistent with a role for rutile in moderating the Nb budget of arc rocks.« less

Fuel Preheat Effects on Soot-Field Structure in Laminar Gas Jet Diffusion Flames Burning in 0-g and 1-g

NASA Technical Reports Server (NTRS)

Konsur, Bogdan; Megaridis, Constantine M.; Griffin, Devon W.

1999-01-01

An experimental investigation conducted at the 2.2-s drop tower of the NASA Lewis Research Center is presented to quantify the influence of moderate fuel preheat on soot-field structure within 0-g laminar gas jet diffusion flames. Parallel work in 1-g is also presented to delineate the effect of elevated fuel temperatures on soot-field structure in buoyant flames. The experimental methodology implements jet diffusion flames of nitrogen-diluted acetylene fuel burning in quiescent air at atmospheric pressure. Fuel preheat of approximately 100 K in the 0-g laminar jet diffusion flames is found to reduce soot loadings in the annular region, but causes an increase in soot volume fractions at the centerline. In addition, fuel preheat reduces the radial extent of the soot field in 0-g. In 1-g, the same fuel preheat levels have a more moderated influence on soot loadings in the annular region, but are also seen to enhance soot concentrations near the axis low in the flame. The increased soot loadings near the flame centerline, as caused by fuel preheat, are consistent with the hypothesis that preheat levels of approximately 100 K enhance fuel pyrolysis rates. The results show that the growth stage of particles transported along the soot annulus is shortened both in 1-g and 0-g when elevated fuel temperatures are used.

Ecosystem services and urban heat riskscape moderation: water, green spaces, and social inequality in Phoenix, USA.

PubMed

Jenerette, G Darrel; Harlan, Sharon L; Stefanov, William L; Martin, Chris A

2011-10-01

Urban ecosystems are subjected to high temperatures--extreme heat events, chronically hot weather, or both-through interactions between local and global climate processes. Urban vegetation may provide a cooling ecosystem service, although many knowledge gaps exist in the biophysical and social dynamics of using this service to reduce climate extremes. To better understand patterns of urban vegetated cooling, the potential water requirements to supply these services, and differential access to these services between residential neighborhoods, we evaluated three decades (1970-2000) of land surface characteristics and residential segregation by income in the Phoenix, Arizona, USA metropolitan region. We developed an ecosystem service trade-offs approach to assess the urban heat riskscape, defined as the spatial variation in risk exposure and potential human vulnerability to extreme heat. In this region, vegetation provided nearly a 25 degrees C surface cooling compared to bare soil on low-humidity summer days; the magnitude of this service was strongly coupled to air temperature and vapor pressure deficits. To estimate the water loss associated with land-surface cooling, we applied a surface energy balance model. Our initial estimates suggest 2.7 mm/d of water may be used in supplying cooling ecosystem services in the Phoenix region on a summer day. The availability and corresponding resource use requirements of these ecosystem services had a strongly positive relationship with neighborhood income in the year 2000. However, economic stratification in access to services is a recent development: no vegetation-income relationship was observed in 1970, and a clear trend of increasing correlation was evident through 2000. To alleviate neighborhood inequality in risks from extreme heat through increased vegetation and evaporative cooling, large increases in regional water use would be required. Together, these results suggest the need for a systems evaluation of the benefits, costs, spatial structure, and temporal trajectory for the use of ecosystem services to moderate climate extremes. Increasing vegetation is one strategy for moderating regional climate changes in urban areas and simultaneously providing multiple ecosystem services. However, vegetation has economic, water, and social equity implications that vary dramatically across neighborhoods and need to be managed through informed environmental policies.

Probability-based classifications for spatially characterizing the water temperatures and discharge rates of hot springs in the Tatun Volcanic Region, Taiwan.

PubMed

Jang, Cheng-Shin

2015-05-01

Accurately classifying the spatial features of the water temperatures and discharge rates of hot springs is crucial for environmental resources use and management. This study spatially characterized classifications of the water temperatures and discharge rates of hot springs in the Tatun Volcanic Region of Northern Taiwan by using indicator kriging (IK). The water temperatures and discharge rates of the springs were first assigned to high, moderate, and low categories according to the two thresholds of the proposed spring classification criteria. IK was then used to model the occurrence probabilities of the water temperatures and discharge rates of the springs and probabilistically determine their categories. Finally, nine combinations were acquired from the probability-based classifications for the spatial features of the water temperatures and discharge rates of the springs. Moreover, various combinations of spring water features were examined according to seven subzones of spring use in the study region. The research results reveal that probability-based classifications using IK provide practicable insights related to propagating the uncertainty of classifications according to the spatial features of the water temperatures and discharge rates of the springs. The springs in the Beitou (BT), Xingyi Road (XYR), Zhongshanlou (ZSL), and Lengshuikeng (LSK) subzones are suitable for supplying tourism hotels with a sufficient quantity of spring water because they have high or moderate discharge rates. Furthermore, natural hot springs in riverbeds and valleys should be developed in the Dingbeitou (DBT), ZSL, Xiayoukeng (XYK), and Macao (MC) subzones because of low discharge rates and low or moderate water temperatures.

Microstructural evolution and mechanical characterization for the A508-3 steel before and after phase transition

NASA Astrophysics Data System (ADS)

Lu, Chuanyang; He, Yanming; Gao, Zengliang; Yang, Jianguo; Jin, Weiya; Xie, Zhigang

2017-11-01

Nuclear power, as a reliable clean and economical energy source, has gained great attention from all over the world. The A508-3 steel will be introduced as the structural materials for Chinese nuclear reactor pressure vessels (RPVs). This work investigated the temperature-dependence microstructural evolution during high-temperature heat treatments, and built the relationship between the microstructure and mechanical properties for the steel before and after phase transition. The results show that the original steel consists of the bainite, allotriomorphic ferrite, retained austenite and few Mo-rich M2C carbides. The phase-transition temperature of the steel is determined to be 750 °C. The tensile tests performed at 20-1000 °C indicate that both of the yield strength and ultimate tensile strength decrease monotonously with increasing the temperature. Before phase transition, precipitation of cementite from the retained austenite and coarsening of cementite at the austenite-ferrite interphases should be responsible for their sharp decrease. After phase transition, the growth of austenite grain reduces the strength moderately. As for the elongation, however, it increases dramatically when the testing temperature is over 750 °C, due to the dissolution of cementite and formation of austenite. The obtained results will provide some fundamental data to understand and implement the In-Vessel Retention strategy.

[Effects of water stress and temperature on gas exchange and chlorophyll fluorescence of Sinocalycanthus chinensis leaves].

PubMed

Ke, Shi-sheng; Jin, Ze-xin

2008-01-01

Sinocalycanthus chinensis is an endangered species in Sinocalycanthus, and only distributed in Zhejiang Province of China. This paper studied the photosynthetic responses of 2-year-old pot-cultured S. chinensis to different levels of water stress and temperature. The results indicated that under mild and moderate water stress, the net photosynthetic rate (Pn) of S. chinensis leaves was decreased to 92.3% and 74.3% of the control, respectively, which was mainly attributed to stomatal limitation; and under severe water stress, the Pn was decreased to 44.4% of the control, which might be mainly linked to non-stomatal limitation. The appropriate temperature for S. chinensis photosynthesis was from 20 degrees C to 28 degrees C. At 39 degrees C, the Pn, water use efficiency (WUE), and maximal photochemistry efficiency (Fv/Fm) were decreased significantly, while the dark respiration rate (Rd) and transpiration rate (Tr) were enhanced significantly. With increasing water stress and temperature, some photosynthetic parameters including light saturation point (LSP), apparent quantum yield (AQY) and maximal CO2 assimilation rate (Pmax) decreased to certain extents, while light compensation point (LCP) increased, suggesting that both severe water stress and higher temperature were the important environmental factors affecting the survival of S. chinensis.

Implementation of a multidisciplinary guideline improves preterm infant admission temperatures.

PubMed

Harer, M W; Vergales, B; Cady, T; Early, A; Chisholm, C; Swanson, J R

2017-11-01

Hypothermia is a common problem in preterm infants immediately following delivery.Local problem:The rate of admission hypothermia in our neonatal intensive care unit (NICU) was above the rate of comparable NICUs in the Vermont Oxford Network. To reduce the rate of preterm admission hypothermia, a quality improvement (QI) project was implemented, utilizing the plan-do-study-act (PDSA) methodology. A guideline for delivery room thermoregulation management in <35-week infants at the University of Virginia was created and put into practice by a multidisciplinary team. Clinical practice changes in the guideline included: increasing operating room temperatures, obtaining a 10-min axillary temperature, using an exothermic mattress for all infants <35 weeks, and using a polyethylene wrap for infants <32 weeks. The baseline rate of hypothermia (<36.5 °CC) was 63%. Three PDSA cycles data were completed on 168 consecutive preterm births. The post-implementation rate of hypothermia (<36.5 °C) was reduced to 30% (P<0.001). The incidence of moderate hypothermia (< 36 °C) was reduced from a baseline of 29% to a rate of 9% (P<0.001). Use of a multidisciplinary guideline to increase preterm NICU admission temperatures resulted in a decrease in hypothermic infants.

Solid state thin film battery having a high temperature lithium alloy anode

DOEpatents

Hobson, David O.

1998-01-01

An improved rechargeable thin-film lithium battery involves the provision of a higher melting temperature lithium anode. Lithium is alloyed with a suitable solute element to elevate the melting point of the anode to withstand moderately elevated temperatures.

Riparian forest as a management tool for moderating future thermal conditions of lowland temperate streams

NASA Astrophysics Data System (ADS)

Kristensen, P. B.; Kristensen, E. A.; Riis, T.; Baisner, A. J.; Larsen, S. E.; Verdonschot, P. F. M.; Baattrup-Pedersen, A.

2013-05-01

Predictions of the future climate infer that stream water temperatures may increase in temperate lowland areas and that streams without riparian forest will be particularly prone to elevated stream water temperature. Planting of riparian forest is a potential mitigation measure to reduce water temperatures for the benefit of stream organisms. However, no studies have yet determined the length of a forested reach required to obtain a significant temperature decrease. To investigate this we measured the temperature in five small Danish lowland streams from June 2010 to July 2011, all showing a sharp transition between an upstream open reach and a downstream forested reach. In all stream reaches we also measured canopy cover and a range of physical variables characterizing the streams reaches. This allowed us to analyse differences in mean daily temperature and amplitude per month among forested and open sections as well as to study annual temperature regimes and the influence of physical conditions on temperature changes. Stream water temperature in the open reaches was affected by heating, and in July we observed an increase in temperature over the entire length of the investigated reaches, reaching temperatures higher than the incipient lethal limit for brown trout. Along the forest reaches a significant decrease in July temperatures was recorded immediately (100 m) when the stream moved into the forested area. In three of our study streams the temperature continued to decrease the longer the stream entered into the forested reach, and the temperature decline did not reach a plateau. The temperature increases along the open reaches were accompanied by stronger daily temperature variation; however, when the streams entered into the forest, the range in daily variation decreased. Multiple regression analysis of the combined effects on stream water temperature of canopy cover, Width/Depth ratio, discharge, current velocity and water temperature revealed that canopy cover and Width/Depth were the two variables responsible for the reduced temperature observed when the streams enter the forest. In consequence, we conclude that even relatively short stretches (100-500 m) of forest alongside streams may combat the negative effects of heating of stream water and that forest planting can be a useful mitigation measure.

Warming and wetting signals emerging from analysis of changes in climate extreme indices over South America

NASA Astrophysics Data System (ADS)

Skansi, María de los Milagros; Brunet, Manola; Sigró, Javier; Aguilar, Enric; Arevalo Groening, Juan Andrés; Bentancur, Oscar J.; Castellón Geier, Yaruska Rosa; Correa Amaya, Ruth Leonor; Jácome, Homero; Malheiros Ramos, Andrea; Oria Rojas, Clara; Pasten, Alejandro Max; Sallons Mitro, Sukarni; Villaroel Jiménez, Claudia; Martínez, Rodney; Alexander, Lisa V.; Jones, P. D.

2013-01-01

Here we show and discuss the results of an assessment of changes in both area-averaged and station-based climate extreme indices over South America (SA) for the 1950-2010 and 1969-2009 periods using high-quality daily maximum and minimum temperature and precipitation series. A weeklong regional workshop in Guayaquil (Ecuador) provided the opportunity to extend the current picture of changes in climate extreme indices over SA. Our results provide evidence of warming and wetting across the whole SA since the mid-20th century onwards. Nighttime (minimum) temperature indices show the largest rates of warming (e.g. for tropical nights, cold and warm nights), while daytime (maximum) temperature indices also point to warming (e.g. for cold days, summer days, the annual lowest daytime temperature), but at lower rates than for minimums. Both tails of night-time temperatures have warmed by a similar magnitude, with cold days (the annual lowest nighttime and daytime temperatures) seeing reductions (increases). Trends are strong and moderate (moderate to weak) for regional-averaged (local) indices, most of them pointing to a less cold SA during the day and warmer night-time temperatures. Regionally-averaged precipitation indices show clear wetting and a signature of intensified heavy rain events over the eastern part of the continent. The annual amounts of rainfall are rising strongly over south-east SA (26.41 mm/decade) and Amazonia (16.09 mm/decade), but north-east Brazil and the western part of SA have experienced non-significant decreases. Very wet and extremely days, the annual maximum 5-day and 1-day precipitation show the largest upward trends, indicating an intensified rainfall signal for SA, particularly over Amazonia and south-east SA. Local trends for precipitation extreme indices are in general less coherent spatially, but with more general spatially coherent upward trends in extremely wet days over all SA.

N95 filtering facepiece respirator deadspace temperature and humidity.

PubMed

Roberge, Raymond J; Kim, Jung-Hyun; Benson, Stacey

2012-01-01

The objective of this study was to determine the levels of heat and humidity that develop within the deadspace of N95 filtering facepiece respirators (N95 FFR). Seventeen subjects wore two models each of N95 FFR and N95 FFR with an exhalation valve (N95 FFR/EV) while exercising on a treadmill at a low-moderate work rate for 1 and 2 hr in a temperate ambient environment. FFR deadspace temperature and relative humidity were monitored by a wireless sensor housed within the FFR. Each FFR was weighed pre- and post-testing to determine moisture retention. After 1 hr, FFR deadspace temperature and humidity were markedly elevated above ambient levels, and the FFR deadspace mean apparent heat index was 54°C. N95 FFR/EV use resulted in significantly lower deadspace temperatures than N95 FFR (p = 0.01), but FFR deadspace humidity levels were not significantly different (p = 0.32). Compared with the first hour of use, no significant increase in FFR deadspace heat and humidity occurred over the second hour. FFR mean moisture retention was < 0.3 grams over 2 hr. N95 FFR/EV offer a significant advantage in deadspace heat dissipation over N95 FFR at a low-moderate work rate over 1 hr of continuous use but offered no additional benefit in humidity amelioration. Moisture retention in N95 FFR and N95 FFR/EV is minimal after 2 hr of use. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a file containing N95 filtering facepiece respirator deadspace mean RH and temperature recordings for 17 subjects treadmill exercising at 5.6 Km/H over 1 hour.].

Examination of the effect of ageing and temperature at rigor on colour stability of lamb meat.

PubMed

Hopkins, D L; Lamb, T A; Kerr, M J; van de Ven, R J; Ponnampalam, E N

2013-10-01

A study of factors (ageing period, rigor temperature and vitamin E level) impacting on the colour stability of lamb m. longissimus thoracis et lumborum (LL) during 3 days of simulated retail display was undertaken. The LL were taken from 84 lambs from 3 slaughters. Slices of LL were measured fresh (24h post-mortem) or after ageing for 5 days in vacuum packaging. The oxy/met ratio (630/580 nm), declined with display time, and increased with increasing temperature at pH6.0. Redness (a*) values also declined with display time and a reduction in redness values was observed as LL pH at 24h post-mortem and/or pH at 18°C increased. There was no effect of ageing period or vitamin E level on the oxy/met ratio or a* values when the vitamin E level averaged 3.76 mg/kg LL. These results suggest that maximising vitamin E levels in lambs and achieving a moderate rate of pH decline will optimise colour stability irrespective of ageing period. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

PRELIMINARY HAZARDS SUMMARY REPORT FOR THE VALLECITOS SUPERHEAT REACTOR

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

Murray, J.L.

1961-02-01

BS>The Vallecitos Superheat Reactor (VSR) is a light-watermoderated, thermal-spectrum reactor, cooled by a combination of moderator boiling and forced convection cooling with saturated steam. The reactor core consists of 32 fuel hurdles containing 5300 lb of UO/sub 2/ enriched in U/sub 235/ to 3.6%. The fuel elements are arranged in individual process tubes that direct the cooling steam flow and separate the steam from the water moderator. The reactor vessel is designed for 1250 psig and operates at 960 to 1000 psig. With the reactor operating at 12.5 Mw(t), the maximum fuel cladding temperature is 1250 deg F and themore » cooling steam is superheated to an average temperature of about 810 deg F at 905 psig. Nu clear operation of the reactor is controlled by 12 control rods, actuated by drives mounted on the bottom of the reactor vessel. The water moderator recirculates inside the reactor vessel and through the core region by natural convection. Inherent safety features of the reactor include the negative core reactivity effects upon heating the UO/sub 2/ fuel (Doppler effect), upon increasing the temperature or void content of the moderator in the operating condition, and upon unflooding the fuel process tubes in the hot condition. Snfety features designed into the reactor and plant systems include a system of sensors and devices to detect petentially unsafe operating conditions and to initiate automatically the appropriate countermeasures, a set of fast and reliable control rods for scramming the reactor if a potentially unsafe condition occurs, a manually-actuated liquid neutron poison system, and an emergency cooling system to provide continued steam flow through the reactor core in the event the reactor becomes isolated from either its normal source of steam supply or discharge. The release of radioactivity to unrestricted areas is maintained within permissible limits by monitoring the radioactivity of wastes and controlling their release. The reactor and many of its auxiliaries are housed within a high-integrity essentially leak-tight containment vessel. (auth)« less

Cardiorespiratory parameters in draught horses before and after short term draught work pulling loads.

PubMed

Pérez, R; Recabarren, S E; Mora, G; Jara, C; Quijada, G; Hetz, E

1992-04-01

In order to establish the relationship between draught force and cardiorespiratory responses to exercise heart rate (HR), respiratory rate (RR), arterial and venous blood gases, pH, hemoglobin concentration and temperature were measured in five draught horses during rest, immediately after exercise and 30 min post-exercise under field conditions. A wagon equipped with an odometer and a hydraulic dynamometer was used for measuring distance and draught force. The wagon was loaded with 946 kg for the low load, 1,979 kg for the medium load and 2,994 kg for the high load, and drawn for a distance of 1,500 m. Draught force and load weight were linearly related. The response of the draught horse to low and medium load exercise was characterized by a moderate increase in HR, RR and temperature with no significant changes in arterial blood gases and pH. An increase in HR, RR and temperature was observed, whereas no changes in arterial PO2 and increases in venous PO2 were noticed after high load exercise. Slight increase in venous lactic acid concentration as a result of high load exercise was observed, suggesting that some anaerobic work was performed. However this was insufficient to produce changes in blood pH. The increase in metabolic requirements during the three levels of draught exercise was associated with increases in arterial hemoglobin concentration and oxygen content of blood.

Stabilization of lead in incineration fly ash by moderate thermal treatment with sodium hydroxide addition

PubMed Central

Yang, Yuanyi; He, Yong; Sun, Xiaolong; Ge, Li-Ya; Zhang, Kewei; Yang, Weizhong

2017-01-01

Municipal solid waste (MSW) incineration fly ash (IFA) can be potentially reused as a substitute for some raw materials, but treatment for detoxification is indispensable owing to high contents of heavy metals in fly ash. In the present work, due to excessive leaching concentration of lead (Pb), a moderate thermal treatment with sodium hydroxide (NaOH) addition was employed to stabilize Pb in IFA. The moderate thermal treatment was performed under relatively low temperature ranging from 300 to 500°C and at retention time from 1 to 3 h with NaOH addition in a range of 1 to 9%. Leaching results showed that leaching concentrations of Pb in IFA leachates decreased below the standard for hazardous waste identification (5 mg/L) in China under all treatment scenarios. With the increase of temperature, retention time and the amount of NaOH, the concentration of Pb were further suppressed in IFA leachates. Especially, at 500°C for 3 h with 9% NaOH addition, the concentration of Pb dropped to 0.18 mg/L, which was below the standard for sanitary landfill (0.25 mg/L) in China. In thermal process, needle-like crystallites melted to form granules and clumps with compacter structure and less pores. After the thermal treatment, water-soluble and exchangeable fractions of Pb significantly decreased. Therefore, the thermal treatment coupled with NaOH could be applied to realize the environmentally sound management of MSW IFA. PMID:28586368

Stabilization of lead in incineration fly ash by moderate thermal treatment with sodium hydroxide addition.

PubMed

Gong, Bing; Deng, Yi; Yang, Yuanyi; He, Yong; Sun, Xiaolong; Ge, Li-Ya; Zhang, Kewei; Yang, Weizhong

2017-01-01

Municipal solid waste (MSW) incineration fly ash (IFA) can be potentially reused as a substitute for some raw materials, but treatment for detoxification is indispensable owing to high contents of heavy metals in fly ash. In the present work, due to excessive leaching concentration of lead (Pb), a moderate thermal treatment with sodium hydroxide (NaOH) addition was employed to stabilize Pb in IFA. The moderate thermal treatment was performed under relatively low temperature ranging from 300 to 500°C and at retention time from 1 to 3 h with NaOH addition in a range of 1 to 9%. Leaching results showed that leaching concentrations of Pb in IFA leachates decreased below the standard for hazardous waste identification (5 mg/L) in China under all treatment scenarios. With the increase of temperature, retention time and the amount of NaOH, the concentration of Pb were further suppressed in IFA leachates. Especially, at 500°C for 3 h with 9% NaOH addition, the concentration of Pb dropped to 0.18 mg/L, which was below the standard for sanitary landfill (0.25 mg/L) in China. In thermal process, needle-like crystallites melted to form granules and clumps with compacter structure and less pores. After the thermal treatment, water-soluble and exchangeable fractions of Pb significantly decreased. Therefore, the thermal treatment coupled with NaOH could be applied to realize the environmentally sound management of MSW IFA.

Evaluation of Thermal Stability of Ausferrite in Austempered Ductile Iron Using Differential Scanning Calorimetry

NASA Astrophysics Data System (ADS)

Warsinski, Karl C.

Austempered Ductile Iron (ADI) is prone to changes in microstructure and mechanical properties when exposed to elevated service temperatures. Differential Scanning Calorimetry has been used to evaluate the stabilizing effects of copper, nickel, molybdenum, and cobalt on the ausferrite structure. Previous studies have conflated the effects of various alloy additions, and little effort has been made to systematically catalog the effects of individual elements. The focus of the current research has been to identify alloying elements that more strongly stabilize the ausferrite structure in order to improve service life of ADI at elevated temperatures. Nickel has been shown to have a moderate stabilizing effect, while copper and molybdenum cause a much sharper increase in activation energy. Cobalt has a high stabilizing effect at 0.5% addition by weight, but a further increase to 2.36% results in a slight decrease in activation energy.

EFFECT OF MASSIVE NEUTRON EXPOSURE ON THE DISTORTION OF REACTOR GRAPHITE

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

Helm, J.W.; Davidson, J.M.

1963-05-28

Distortion of reactor-grade graphites was studied at varying neutron exposures ranging up to 14 x 10/sup 21/ neutrons per cm/sup 2/ (nvt)/sup */ at temperatures of irradiation ranging from 425 to 800 deg C. This exposure level corresponds to approximately 100,000 megawatt days per adjacent ton of fuel (Mwd/ At) in a graphite-moderated reactor. A conventionalcoke graphite, CSF, and two needle-coke graphites, NC-7 and NC-8, were studied. At all temperatures of irradiation the contraction rate of the samples cut parallel to the extrusion axis increased with increasing neutron exposure. For parallel samples the needle- coke graphites and the CSF graphitemore » contracted approximately the same amount. In the transverse direction the rate of cortraction at the higher irradiation temperntures appeared to be decreasing. Volume contractions derived from the linear contractions are discussed. (auth)« less

Impact of moderate and extreme climate change scenarios on growth, morphological features, photosynthesis, and fruit production of hot pepper.

PubMed

Lee, Sang Gyu; Kim, Sung Kyeom; Lee, Hee Ju; Lee, Hee Su; Lee, Jin Hyoung

2018-01-01

Horticultural crop production and changes in physiological aspects during the growing season may be affected by climate change factors (CC), which include increased temperature and the associated doubling or tripling of atmospheric CO 2 concentrations. However, the potential effects are complex and many parameters might impact on the observed effects. To evaluate the effects of CC, the growth, yield, fruit characteristics, photosynthetic traits, and morphological characteristics of hot peppers were investigated. The hot peppers were grown under two CC scenarios, with the Representative Concentration Pathway (RCP) of 4.5 (Temp.; +3.4°C, CO 2 conc.; 540 μmol/mol, Precipitation +17.3%) and RCP 8.5 (Temp.; +6.0°C and CO 2 conc.; 940 μmol/mol, Precipitation +20.3%), respectively, using extreme weather simulators. This was compared with existing weather conditions occurring in Jeonju, South Korea in terms of air temperature, relative humidity, radiation, and precipitation. Overall, the plant height showed the highest under moderate CC conditions (RCP 4.5) among all the treatments tested. The number of leaves in the RCP 8.5 condition showed 7,739/plants, which was 2.2 times higher than that of the control. In addition, fruit shape was shortened and percentage dry matter was also the highest. The yield of hot pepper in the CC RCP 4.5 and 8.5 conditions were decreased by 21.5% and 89.2% when compared with that of the control, respectively. The days to harvest in the condition of CC scenarios were shortened from 5 to 13 compared with that of control, predominantly due to the increased air temperature. The results indicated that the severe RCP CC scenarios made reduction in the yields and negative affection on the fruit qualities. Overall, hot pepper was tolerant of mild CC scenarios of temperature × CO 2 but was significantly affected by more extreme CC interacting parameter concentrations (or similar).

Exploring the Appropriate Drought Index in a Humid Tropical Area with Complex Terrain

NASA Astrophysics Data System (ADS)

Lee, C. H.; Chen, W. T.; Lo, M. H.; Chu, J. L.; Chen, Y. J.; Chen, Y. M.

2017-12-01

The goal of the present study is to identify the most appropriate index to monitor droughts in Taiwan, an extremely humid region with steep terrain. Three drought indices were calculated using in situ high resolution rainfall observations and compared: the Standardized Precipitation Index (SPI), the self-calibrating Palmer Drought Severity Index (sc-PDSI), and the Standardized Precipitation Evapotranspiration Index (SPEI). In Taiwan, the average amount of precipitation is around 2500 mm per year, which is six times of the global average. However, with the complexity of topography and the uneven distribution throughout the year in Taiwan, abundant rainfall during the wet season is mostly lost as runoff. Severe droughts occur frequently at approximately once per decade, while moderate droughts occur every 2 years. Earlier studies indicated that the SPI is limited in describing drought events because the temperature effect is not taken into account in SPI as in the sc-PDSI. In addition, SPEI, which take the Penman-Monteith Potential Evapotranspiration (PET_pm) into account, is also considered in the present study. The atmospheric water demand increases as temperature increasing, which is reflected in PET_pm. To calculate the three drought indices, we will use the monthly average temperature to calculate the PET_pm and monthly accumulated precipitation from automatic weather stations from the Central Weather Bureau. All of the detected droughts are evaluated against the dataset of historical drought records in Taiwan. We explore whether the temperature is an important factor for the occurrence of droughts in Taiwan first. In addition to severe droughts, we expect that SPEI and sc-PDSI can detect more moderate droughts in Taiwan. Second, we survey the performance of three drought indices for the detection of droughts in Taiwan. Because the soil water model used in sc-PDSI doesn't consider the effect of steep terrain, and because SPI only considers the monthly precipitation, we expect SPEI to be the more appropriate index for monitoring drought events in Taiwan.

Differential regulation by heat stress of novel cytochrome P450 genes from the dinoflagellate symbionts of reef-building corals.

PubMed

Rosic, Nedeljka N; Pernice, Mathieu; Dunn, Simon; Dove, Sophie; Hoegh-Guldberg, Ove

2010-05-01

Exposure to heat stress has been recognized as one of the major factors leading to the breakdown of the coral-alga symbiosis and coral bleaching. Here, we describe the presence of three new cytochrome P450 (CYP) genes from the reef-building coral endosymbiont Symbiodinium (type C3) and changes in their expression during exposure to severe and moderate heat stress conditions. Sequence analysis of the CYP C-terminal region and two conserved domains, the "PERF" and "heme-binding" domains, confirmed the separate identities of the CYP genes analyzed. In order to explore the effects of different heat stress scenarios, samples of the scleractinian coral Acropora millepora were exposed to elevated temperatures incrementally over an 18-h period (rapid thermal stress) and over a 120-h period (gradual thermal stress). After 18 h of gradual heating and incubation at 26 degrees C, the Symbiodinium CYP mRNA pool was approximately 30% larger, while a further 6 degrees C increase to a temperature above the average sea temperature (29 degrees C after 72 h) resulted in a 2- to 4-fold increase in CYP expression. Both rapid heat stress and gradual heat stress at 32 degrees C resulted in 50% to 90% decreases in CYP gene transcript abundance. Consequently, the initial upregulation of expression of CYP genes at moderately elevated temperatures (26 degrees C and 29 degrees C) was followed by a decrease in expression under the greater thermal stress conditions at 32 degrees C. These findings indicate that in the coral-alga symbiosis under heat stress conditions there is production of chemical stressors and/or transcriptional factors that regulate the expression of genes, such as the genes encoding cytochrome P450 monooxygenases, that are involved in the first line of an organism's chemical defense.

Shifting the Arctic Carbon Balance: Effects of a Long-Term Fertilization Experiment and Anomalously Warm Temperatures on Net Ecosystem Exchange in the Alaskan Tundra

NASA Astrophysics Data System (ADS)

Ludwig, S.; Natali, S.; Rastetter, E. B.; Shaver, G. R.; Graham, L. M.; Jastrow, J. D.

2017-12-01

The arctic is warming at an accelerated rate relative to the globe. Among the predicted consequences of warming temperatures in the arctic are increased gross primary productivity (GPP), ecosystem respiration (ER), and nutrient availability. The net effect of these changes on the carbon (C) cycle and resulting C balance and feedback to climate change remain unclear. Historically the Arctic has been a C sink, but evidence from recent years suggests some regions in the Arctic are becoming C sources. To predict the role of the Arctic in global C cycling, the mechanisms affecting arctic C balances need to be better resolved. We measured net ecosystem exchange (NEE) in a long-term, multi-level, fertilization experiment at Toolik Lake, AK during an anomalously warm summer. We modeled NEE, ER, and GPP using a Bayesian network model. The best-fit model included Q10 temperature functions and linear fertilization functions for both ER and GPP. ER was more strongly affected by temperature and GPP was driven more by fertilization level. As a result, fertilization increased the C sink capacity, but only at moderate and low temperatures. At high temperatures (>28 °C) the NEE modeled for the highest level of fertilization was not significantly different from zero. In contrast, at ambient nutrient levels modeled NEE was significantly below zero (net uptake) until 35 °C, when it becomes neutral. Regardless of the level of fertilization, NEE never decreased with warming. Temperature in low ranges (5-15°C) had no net effect on NEE, whereas NEE began to increase exponentially with temperature after a threshold of 15°C until becoming a net source to the atmosphere at 37°C. Our results indicate that the C sink strength of tundra ecosystems can be increased with small increases in nutrient availability, but that large increase in nutrient availability can switch tundra ecosystems into C sources under warm conditions. Warming temperatures in tundra ecosystems will only decrease C sink strength, and the continued increase in days with anomalously high summer temperatures could lead to the Arctic tundra becoming a source of C and a positive feed back to climate change.

Solid state thin film battery having a high temperature lithium alloy anode

DOEpatents

Hobson, D.O.

1998-01-06

An improved rechargeable thin-film lithium battery involves the provision of a higher melting temperature lithium anode. Lithium is alloyed with a suitable solute element to elevate the melting point of the anode to withstand moderately elevated temperatures. 2 figs.

Dissolved oxygen, stream temperature, and fish habitat response to environmental water purchases.

PubMed

Null, Sarah E; Mouzon, Nathaniel R; Elmore, Logan R

2017-07-15

Environmental water purchases are increasingly used for ecological protection. In Nevada's Walker Basin (western USA), environmental water purchases augment streamflow in the Walker River and increase lake elevation of terminal Walker Lake. However, water quality impairments like elevated stream temperatures and low dissolved oxygen concentrations also limit ecosystems and species, including federally-threatened Lahontan cutthroat trout. In this paper, we prioritize water volumes and locations that most enhance water quality for riverine habitat from potential environmental water rights purchases. We monitored and modeled streamflows, stream temperatures, and dissolved oxygen concentrations using River Modeling System, an hourly, physically-based hydrodynamic and water quality model. Modeled environmental water purchases ranged from average daily increases of 0.11-1.41 cubic meters per second (m 3 /s) during 2014 and 2015, two critically dry years. Results suggest that water purchases consistently cooled maximum daily stream temperatures and warmed nightly minimum temperatures. This prevented extremely low dissolved oxygen concentrations below 5.0 mg/L, but increased the duration of moderate conditions between 5.5 and 6.0 mg/L. Small water purchases less than approximately 0.71 m 3 /s per day had little benefit for Walker River habitat. Dissolved oxygen concentrations were affected by upstream environmental conditions, where suitable upstream water quality improved downstream conditions and vice versa. Overall, this study showed that critically dry water years degrade environmental water quality and habitat, but environmental water purchases of at least 0.71 m 3 /s were promising for river restoration. Published by Elsevier Ltd.

Status of alewife and rainbow smelt in U.S. waters of Lake Ontario, 2015

USGS Publications Warehouse

Walsh, Maureen; Weidel, Brian C.; Connerton, Michael J.; Holden, Jeremy P.

2016-01-01

In 2015 the joint USGS and NYSDEC surveys for Alewife and Rainbow Smelt were combined for the first time into a comprehensive spring pelagic prey fish survey. The adult Alewife abundance and weight indices in 2015 increased slightly from 2014 levels, and adult Alewife abundance has remained relatively stable for the past five years. Adult Alewife condition in both spring and fall increased from 2014 values and was above long-term means. Yearling Alewife abundance was the lowest observed in the 38-year time series. Alewife year class strength at age 1 is related to the number of spawning adults and summer temperatures and winter duration in the first year after hatching. Moderate year classes were produced during 2009-2011, and 2012 was the largest year class in the time series. However, severe winters in 2013-2014 and 2014-2015 contributed to two successive very small year classes for the first time in the time series. We expect adult Alewife abundance and biomass to decline in 2016 as older and larger fish decline in the population. The number of spawning adults increased in 2015, summer temperatures were slightly below average, and the anticipated winter duration is below average (i.e., milder winter) for 2015-2016, so these conditions will likely produce a low to moderate year class. A third successive weak year class could be problematic for the Lake Ontario Alewife population and may be of concern to binational lake managers. Rainbow Smelt were also assessed and the population continues to persist at a low and stable level.

The effect of sub-floor heating on house-dust-mite populations on floors and in furniture.

PubMed

de Boer, Rob

2003-01-01

It is well known that dehydrating conditions for house dust mites can be created by simply raising the temperature, causing loss of body water and eventually death. Thus, it can be expected that conditions for dust mites are less favourable on floors supplied with sub-floor heating. This was examined in a study of 16 houses with sub-floor heating and 21 without. The pattern of changes in air humidity and temperature on the floors was investigated and compared to known data of the tolerance of dust mites. Also the resident mite populations were compared. Floors with sub-floor heating had, on average, fewer mites, but the difference with unheated floors was small. It was remarkable that mite numbers were also lower in upholstered furniture. Another important observation was that some houses with sub-floor heating had high mite numbers, indicating that this type of heating is compatible with a thriving mite population. Temperature and humidity conditions of heated floors may allow mites not only to survive, but also to remain active in winter. A moderate increase in temperature, a moderate decrease in (absolute) air humidity, or a combination of both, will suffice to keep the humidity all winter below the Critical Equilibrium Humidity, the level of air humidity that is critical for mite growth and reproduction, hence for allergen production. However, it is argued that measures to suppress allergen production by house dust mites are likely to be far more effective if taken in summer rather than in winter.

Poaceae pollen in the air depending on the thermal conditions.

PubMed

Myszkowska, Dorota

2014-07-01

The relationship between the meteorological elements, especially the thermal conditions and the Poaceae pollen appearance in the air, were analysed as a basis to construct a useful model predicting the grass season start. Poaceae pollen concentrations were monitored in 1991-2012 in Kraków using the volumetric method. Cumulative temperature and effective cumulative temperature significantly influenced the season start in this period. The strongest correlation was seen as the sum of mean daily temperature amplitudes from April 1 to April 14, with mean daily temperature>15 °C and effective cumulative temperature>3 °C during that period. The proposed model, based on multiple regression, explained 57% of variation of the Poaceae season starts in 1991-2010. When cumulative mean daily temperature increased by 10 °C, the season start was accelerated by 1 day. The input of the interaction between these two independent variables into the factor regression model caused the increase in goodness of model fitting. In 2011 the season started 5 days earlier in comparison with the predicted value, while in 2012 the season start was observed 2 days later compared to the predicted day. Depending on the value of mean daily temperature from March 18th to the 31st and the sum of mean daily temperature amplitudes from April 1st to the 14th, the grass pollen seasons were divided into five groups referring to the time of season start occurrence, whereby the early and moderate season starts were the most frequent in the studied period and they were especially related to mean daily temperature in the second half of March.

Thermal regulation in Macaca mulatta during space flight

NASA Technical Reports Server (NTRS)

Klimovitsky, V. Y.; Alpatov, A. M.; Hoban-Higgins, T. M.; Utekhina, E. S.; Fuller, C. A.

2000-01-01

The results of studies of body temperature and thermal regulation in Macaca mulatta flown on biosatellites Bion 6-11 are presented. The effect of microgravity on deep body temperature as compared to skin temperature was investigated. In most animals, deep body temperature declined moderately and then tended to return to normal. Brain temperature/ankle temperature correlation changed. The system of thermal regulation was found to function adequately in space.

Respiratory Effects of Indoor Heat and the Interaction with Air Pollution in Chronic Obstructive Pulmonary Disease.

PubMed

McCormack, Meredith C; Belli, Andrew J; Waugh, Darryn; Matsui, Elizabeth C; Peng, Roger D; Williams, D'Ann L; Paulin, Laura; Saha, Anik; Aloe, Charles M; Diette, Gregory B; Breysse, Patrick N; Hansel, Nadia N

2016-12-01

There is limited evidence of the effect of exposure to heat on chronic obstructive pulmonary disease (COPD) morbidity, and the interactive effect between indoor heat and air pollution has not been established. To determine the effect of indoor and outdoor heat exposure on COPD morbidity and to determine whether air pollution concentrations modify the effect of temperature. Sixty-nine participants with COPD were enrolled in a longitudinal cohort study, and data from the 601 participant days that occurred during the warm weather season were included in the analysis. Participants completed home environmental monitoring with measurement of temperature, relative humidity, and indoor air pollutants and simultaneous daily assessment of respiratory health with questionnaires and portable spirometry. Participants had moderate to severe COPD and spent the majority of their time indoors. Increases in maximal indoor temperature were associated with worsening of daily Breathlessness, Cough, and Sputum Scale scores and increases in rescue inhaler use. The effect was detected on the same day and lags of 1 and 2 days. The detrimental effect of temperature on these outcomes increased with higher concentrations of indoor fine particulate matter and nitrogen dioxide (P < 0.05 for interaction terms). On days during which participants went outdoors, increases in maximal daily outdoor temperature were associated with increases in Breathlessness, Cough, and Sputum Scale scores after adjusting for outdoor pollution concentrations. For patients with COPD who spend the majority of their time indoors, indoor heat exposure during the warmer months represents a modifiable environmental exposure that may contribute to respiratory morbidity. In the context of climate change, adaptive strategies that include optimization of indoor environmental conditions are needed to protect this high-risk group from the adverse health effects of heat.

Respiratory Effects of Indoor Heat and the Interaction with Air Pollution in Chronic Obstructive Pulmonary Disease

PubMed Central

Belli, Andrew J.; Waugh, Darryn; Matsui, Elizabeth C.; Peng, Roger D.; Williams, D’Ann L.; Paulin, Laura; Saha, Anik; Aloe, Charles M.; Diette, Gregory B.; Breysse, Patrick N.; Hansel, Nadia N.

2016-01-01

Rationale: There is limited evidence of the effect of exposure to heat on chronic obstructive pulmonary disease (COPD) morbidity, and the interactive effect between indoor heat and air pollution has not been established. Objectives: To determine the effect of indoor and outdoor heat exposure on COPD morbidity and to determine whether air pollution concentrations modify the effect of temperature. Methods: Sixty-nine participants with COPD were enrolled in a longitudinal cohort study, and data from the 601 participant days that occurred during the warm weather season were included in the analysis. Participants completed home environmental monitoring with measurement of temperature, relative humidity, and indoor air pollutants and simultaneous daily assessment of respiratory health with questionnaires and portable spirometry. Measurements and Main Results: Participants had moderate to severe COPD and spent the majority of their time indoors. Increases in maximal indoor temperature were associated with worsening of daily Breathlessness, Cough, and Sputum Scale scores and increases in rescue inhaler use. The effect was detected on the same day and lags of 1 and 2 days. The detrimental effect of temperature on these outcomes increased with higher concentrations of indoor fine particulate matter and nitrogen dioxide (P < 0.05 for interaction terms). On days during which participants went outdoors, increases in maximal daily outdoor temperature were associated with increases in Breathlessness, Cough, and Sputum Scale scores after adjusting for outdoor pollution concentrations. Conclusions: For patients with COPD who spend the majority of their time indoors, indoor heat exposure during the warmer months represents a modifiable environmental exposure that may contribute to respiratory morbidity. In the context of climate change, adaptive strategies that include optimization of indoor environmental conditions are needed to protect this high-risk group from the adverse health effects of heat. PMID:27684429

Mass coral mortality under local amplification of 2 °C ocean warming

NASA Astrophysics Data System (ADS)

Decarlo, Thomas M.; Cohen, Anne L.; Wong, George T. F.; Davis, Kristen A.; Lohmann, Pat; Soong, Keryea

2017-03-01

A 2 °C increase in global temperature above pre-industrial levels is considered a reasonable target for avoiding the most devastating impacts of anthropogenic climate change. In June 2015, sea surface temperature (SST) of the South China Sea (SCS) increased by 2 °C in response to the developing Pacific El Niño. On its own, this moderate, short-lived warming was unlikely to cause widespread damage to coral reefs in the region, and the coral reef “Bleaching Alert” alarm was not raised. However, on Dongsha Atoll, in the northern SCS, unusually weak winds created low-flow conditions that amplified the 2 °C basin-scale anomaly. Water temperatures on the reef flat, normally indistinguishable from open-ocean SST, exceeded 6 °C above normal summertime levels. Mass coral bleaching quickly ensued, killing 40% of the resident coral community in an event unprecedented in at least the past 40 years. Our findings highlight the risks of 2 °C ocean warming to coral reef ecosystems when global and local processes align to drive intense heating, with devastating consequences.

The effect of intrinsic crumpling on the mechanics of free-standing graphene

DOE PAGES

Nicholl, Ryan J. T.; Conley, Hiram J.; Lavrik, Nickolay V.; ...

2015-11-06

Free-standing graphene is inherently crumpled in the out-of-plane direction due to dynamic flexural phonons and static wrinkling. We explore the consequences of this crumpling on the effective mechanical constants of graphene. We develop a sensitive experimental approach to probe stretching of graphene membranes under low applied stress at cryogenic to room temperatures. We find that the in-plane stiffness of graphene is 20–100 N m –1 at room temperature, much smaller than 340 N m –1 (the value expected for flat graphene). Moreover, while the in-plane stiffness only increases moderately when the devices are cooled down to 10 K, it approachesmore » 300 N m –1 when the aspect ratio of graphene membranes is increased. Finally, these results indicate that softening of graphene at temperatures <400 K is caused by static wrinkling, with only a small contribution due to flexural phonons. Altogether, these results explain the large variation in reported mechanical constants of graphene devices and pave the way towards controlling their mechanical properties.« less

Thermal and overcharge abuse analysis of a redox shuttle for overcharge protection of LiFePO4

NASA Astrophysics Data System (ADS)

Lamb, Joshua; Orendorff, Christopher J.; Amine, Khalil; Krumdick, Gregory; Zhang, Zhengcheng; Zhang, Lu; Gozdz, Antoni S.

2014-02-01

This work investigated the performance and abuse tolerance of cells protected using the redox shuttle 1,4-bis(2-methoxyethoxy)-2,5-di-tert-butylbenzene. The thermal efficiencies were evaluated using isothermal battery calorimetry. Cells containing the overcharge shuttle were observed to reach a steady state value of approximately 3.8 V, with a small variance in direct proportion to the applied current. In all cases the heat output from the cells was measured to reach ∼90% of the total input power. The heat output was also measured using isothermal calorimetry. At higher rates of overcharge, the data shows that the cell containing the shuttle rapidly reaches a steady state voltage, while the temperature increases until a moderately high steady state temperature is reached. The control cell meanwhile rapidly increases in both applied voltage and cell temperature until cell failure. Two cells in series were taken deliberately out of balance individually, then charged as a single pack to observe the time needed to bring the cells into balance with one another.

An economic evaluation of solar radiation management.

PubMed

Aaheim, Asbjørn; Romstad, Bård; Wei, Taoyuan; Kristjánsson, Jón Egill; Muri, Helene; Niemeier, Ulrike; Schmidt, Hauke

2015-11-01

Economic evaluations of solar radiation management (SRM) usually assume that the temperature will be stabilized, with no economic impacts of climate change, but with possible side-effects. We know from experiments with climate models, however, that unlike emission control the spatial and temporal distributions of temperature, precipitation and wind conditions will change. Hence, SRM may have economic consequences under a stabilization of global mean temperature even if side-effects other than those related to the climatic responses are disregarded. This paper addresses the economic impacts of implementing two SRM technologies; stratospheric sulfur injection and marine cloud brightening. By the use of a computable general equilibrium model, we estimate the economic impacts of climatic responses based on the results from two earth system models, MPI-ESM and NorESM. We find that under a moderately increasing greenhouse-gas concentration path, RCP4.5, the economic benefits of implementing climate engineering are small, and may become negative. Global GDP increases in three of the four experiments and all experiments include regions where the benefits from climate engineering are negative. Copyright © 2015 Elsevier B.V. All rights reserved.

The influence of temperature on limestone sulfation and attrition under fluidized bed combustion conditions

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

Montagnaro, Fabio; Salatino, Piero; Dipartimento di Ingegneria Chimica - Universita degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Napoli

2010-04-15

The influence of temperature on attrition of two limestones during desulfurization in a fluidized bed reactor was investigated. Differences in the microstructure of the two limestones were reflected by a different thickness of the sulfate shell formed upon sulfation and by a different value of the ultimate calcium conversion degree. Particle attrition and fragmentation were fairly small under moderately bubbling fluidization conditions for both limestones. An increase of temperature from 850 C to 900 C led to an increase of the attrition rate, most likely because of a particle weakening effect caused by a faster CO{sub 2} evolution during calcination.more » This weakening effect, however, was not sufficiently strong to enhance particle fragmentation in the bed. The progress of sulfation, associated to the build-up of a hard sulfate shell around the particles, led in any case to a decrease of the extent of attrition. Sulfation at 900 C was less effective than at 850 C, and this was shown to be related to the porosimetric features of the different samples. (author)« less

Effect of Propranolol on Thyroxine-Induced Changes in Body Temperature and Metabolism During Exercise in Dogs

NASA Technical Reports Server (NTRS)

Kaciuba-Uscilko, Hanna; Brzezinska, Zofia; Greenleaf, John E.

1976-01-01

Effects of thyroxine on temperature and metabolism during exercise were studied in dogs after beta-adrenergic blockade. Dogs performed 60 min treadmill exercise of moderate intensity 5 and 72 h following thyroxine injected s. c. in a single dose of 0.1 mg/kg b.w. Thyroxine increased significantly the lipolytic response to exercise as well as blood lactate (LA) concentrations and rectal temperature (T(sub re)) during exercise as early as 5 h following the hormone administration. The changes became more pronounced 72 h after the injection. At rest T(sub re), blood FFA (free fatty acid) and LA levels in the thyroxine-treated dogs did not differ from the control values, and blood glucose was slightly, but significantly higher. Propranolol given intravenously in a dose of 0.25 mg/kg at 30 min of the exercise performed 72 h following thyroxine injection abolished the plasma FFA rise, and inhibited to a certain extent increases in T(sub re) and blood LA concentrations during the next 30 min of exercise.

Monte Carlo study of magnetic nanoparticles adsorbed on halloysite Al2Si2O5(OH) 4 nanotubes

NASA Astrophysics Data System (ADS)

Sotnikov, O. M.; Mazurenko, V. V.; Katanin, A. A.

2017-12-01

We study properties of magnetic nanoparticles adsorbed on the halloysite surface. For that a distinct magnetic Hamiltonian with a random distribution of spins on a cylindrical surface was solved by using a nonequilibrium Monte Carlo method. The parameters for our simulations, the anisotropy constant, nanoparticle size distribution, saturated magnetization, and geometrical characteristics of the halloysite template, were taken from recent experiments. We calculate the hysteresis loops and temperature dependence of the zero-field-cooling (ZFC) susceptibility, the maximum of which determines the blocking temperature. It is shown that the dipole-dipole interaction between nanoparticles moderately increases the blocking temperature and weakly increases the coercive force. The obtained hysteresis loops (e.g., the value of the coercive force) for Ni nanoparticles are in reasonable agreement with the experimental data. We also discuss the sensitivity of the hysteresis loops and ZFC susceptibilities to the change in anisotropy and dipole-dipole interaction, as well as the 3 d -shell occupation of the metallic nanoparticles; in particular we predict larger coercive force for Fe than for Ni nanoparticles.

The effect of intrinsic crumpling on the mechanics of free-standing graphene

PubMed Central

Nicholl, Ryan J.T.; Conley, Hiram J.; Lavrik, Nickolay V.; Vlassiouk, Ivan; Puzyrev, Yevgeniy S.; Sreenivas, Vijayashree Parsi; Pantelides, Sokrates T.; Bolotin, Kirill I.

2015-01-01

Free-standing graphene is inherently crumpled in the out-of-plane direction due to dynamic flexural phonons and static wrinkling. We explore the consequences of this crumpling on the effective mechanical constants of graphene. We develop a sensitive experimental approach to probe stretching of graphene membranes under low applied stress at cryogenic to room temperatures. We find that the in-plane stiffness of graphene is 20–100 N m−1 at room temperature, much smaller than 340 N m−1 (the value expected for flat graphene). Moreover, while the in-plane stiffness only increases moderately when the devices are cooled down to 10 K, it approaches 300 N m−1 when the aspect ratio of graphene membranes is increased. These results indicate that softening of graphene at temperatures <400 K is caused by static wrinkling, with only a small contribution due to flexural phonons. Together, these results explain the large variation in reported mechanical constants of graphene devices and pave the way towards controlling their mechanical properties. PMID:26541811

Effect of land cover and green space on land surface temperature of a fast growing economic region in Malaysia

NASA Astrophysics Data System (ADS)

Sheikhi, A.; Kanniah, K. D.; Ho, C. H.

2015-10-01

Green space must be increased in the development of new cities as green space can moderate temperature in the cities. In this study we estimated the land surface temperature (LST) and established relationships between LST and land cover and various vegetation and urban surface indices in the Iskandar Malaysia (IM) region. IM is one of the emerging economic gateways of Malaysia, and is envisaged to transform into a metropolis by 2025. This change may cause increased temperature in IM and therefore we conducted a study by using Landsat 5 image covering the study region (2,217 km2) to estimate LST, classify different land covers and calculate spectral indices. Results show that urban surface had highest LST (24.49 °C) and the lowest temperature was recorded in, forest, rubber and water bodies ( 20.69 to 21.02°C). Oil palm plantations showed intermediate mean LST values with 21.65 °C. We further investigated the relationship between vegetation and build up densities with temperature. We extracted 1000 collocated pure pixels of Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI), Normalized Difference Built-up Index (NDBI), Urban Index (UI) and LST in the study area. Results show a strong and significant negative correlation with (R2= -0.74 and -0.79) respectively between NDVI, NDWI and LST . Meanwhile a strong positive correlation (R2=0.8 and 0.86) exists between NDBI, UI and LST. These results show the importance of increasing green cover in urban environment to combat any adverse effects of climate change.

Au/Cr Sputter Coating for the Protection of Alumina During Sliding at High Temperatures

NASA Technical Reports Server (NTRS)

Benoy, Patricia A.; Dellacorte, Christopher

1995-01-01

A sputter deposited bilayer coating of gold and chromium was investigated as a potential solid lubricant to protect alumina substrates in applications involving sliding at high temperature. The proposed lubricant was tested in a pin-on-disk tribometer with coated alumina disks sliding against uncoated alumina pins. Three test parameters; temperature, load, and sliding velocity were varied over a wide range in order to determine the performance envelope on the gold/chromium (Au/Cr) solid lubricant film. The tribo-tests were run in an air atmosphere at temperatures of 25 to 1000 C, under loads of 4.9 to 49.0 N and at sliding velocities from 1 to 15 m/sec. Post test analyses included surface profilometry, wear factor determination and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) examination of worn surfaces. Compared to unlubricated Al2O3 sliding, the use of the Au/Cr film reduced friction by 30 to 50 percent and wear by one to two orders of magnitude. Increases in test temperature resulted in lower friction and the Au/Cr film continued to provide low friction, about 0.3, even at 1000 C. Pin wear factors and friction were largely unaffected by increasing loads up to 29.4 N. Sliding velocity had essentially no effect on friction, however, increased velocity reduced coating life (total sliding distance). Based upon these research results, the Au/Cr film is a promising lubricant for moderately loaded, low speed applications operating at temperatures as high as 1000 C.

Implementation of the direct S ( α , β ) method in the KENO Monte Carlo code

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

Hart, Shane W. D.; Maldonado, G. Ivan

The Monte Carlo code KENO contains thermal scattering data for a wide variety of thermal moderators. These data are processed from Evaluated Nuclear Data Files (ENDF) by AMPX and stored as double differential probability distribution functions. The method examined in this study uses S(α,β) probability distribution functions derived from the ENDF data files directly instead of being converted to double differential cross sections. This allows the size of the cross section data on the disk to be reduced substantially amount. KENO has also been updated to allow interpolation in temperature on these data so that problems can be run atmore » any temperature. Results are shown for several simplified problems for a variety of moderators. In addition, benchmark models based on the KRITZ reactor in Sweden were run, and the results are compared with the previous versions of KENO without the direct S(α,β) method. Results from the direct S(α,β) method compare favorably with the original results obtained using the double differential cross sections. Finally, sampling the data increases the run-time of the Monte Carlo calculation, but memory usage is decreased substantially.« less

Implementation of the direct S ( α , β ) method in the KENO Monte Carlo code

DOE PAGES

Hart, Shane W. D.; Maldonado, G. Ivan

2016-11-25

The Monte Carlo code KENO contains thermal scattering data for a wide variety of thermal moderators. These data are processed from Evaluated Nuclear Data Files (ENDF) by AMPX and stored as double differential probability distribution functions. The method examined in this study uses S(α,β) probability distribution functions derived from the ENDF data files directly instead of being converted to double differential cross sections. This allows the size of the cross section data on the disk to be reduced substantially amount. KENO has also been updated to allow interpolation in temperature on these data so that problems can be run atmore » any temperature. Results are shown for several simplified problems for a variety of moderators. In addition, benchmark models based on the KRITZ reactor in Sweden were run, and the results are compared with the previous versions of KENO without the direct S(α,β) method. Results from the direct S(α,β) method compare favorably with the original results obtained using the double differential cross sections. Finally, sampling the data increases the run-time of the Monte Carlo calculation, but memory usage is decreased substantially.« less

Effects of MDMA on body temperature in humans

PubMed Central

Liechti, Matthias E

2014-01-01

Hyperthermia is a severe complication associated with the recreational use of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy). In this review, the clinical laboratory studies that tested the effects of MDMA on body temperature are summarized. The mechanisms that underlie the hyperthermic effects of MDMA in humans and treatment of severe hyperthermia are presented. The data show that MDMA produces an acute and dose-dependent rise in core body temperature in healthy subjects. The increase in body temperature is in the range of 0.2-0.8°C and does not result in hyperpyrexia (>40°C) in a controlled laboratory setting. However, moderately hyperthermic body temperatures >38.0°C occur frequently at higher doses, even in the absence of physical activity and at room temperature. MDMA primarily releases serotonin and norepinephrine. Mechanistic clinical studies indicate that the MDMA-induced elevations in body temperature in humans partially depend on the MDMA-induced release of norepinephrine and involve enhanced metabolic heat generation and cutaneous vasoconstriction, resulting in impaired heat dissipation. The mediating role of serotonin is unclear. The management of sympathomimetic toxicity and associated hyperthermia mainly includes sedation with benzodiazepines and intravenous fluid replacement. Severe hyperthermia should primarily be treated with additional cooling and mechanical ventilation. PMID:27626046

Heat stress in front and rear cockpits of F-4 aircraft

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

Nunneley, S.A.; Stribley, R.F.; Allan, J.R.

The thermal stresses encountered in the front and rear cockpits of F-4 aircraft flying low-level missions in warm, moderately humid weather and physiological responses to these stresses are investigated. Measurements of ground and cockpit environmental temperatures and subject skin and core temperatures were acquired for the preflight taxi, low-level flight, ordnance delivery and postflight taxi phases of 36 flights of F-4E aircraft performed to simulate low-level ground attack missions. Cockpit dry-bulb temperatures are found to exceed those on the ground during ground operations, and to decrease in flight in the front, but not the rear, cockpit. A linear relationship betweenmore » cockpit dry bulb and temperatures is also found in each of the mission phases, along with increases in skin and core temperatures with cockpit temperatures and sweat rates depending both on cockpit temperatures and the amount of clothing worn. Adverse physiological effects related to nausea and acceleration tolerances are also noted. It is concluded that the cockpit cooling system of the F-4 allows the development of operationally significant heat stress, which may be corrected by better design and testing of the cooling system.« less

A modeling assessment of the thermal regime for an urban sport fishery

USGS Publications Warehouse

Bartholow, John M.

1991-01-01

Water temperature is almost certainly a limiting factor in the maintenance of a self-sustaining rainbow trout (Oncorhynchus mykiss, formerly Salmo gairdneri) and brown trout (Salmo trutta) fishery in the lower reaches of the Cache la Poudre River near Fort Collins, Colorado, USA. Irrigation diversions dewater portions of the river, but cold reservoir releases moderate water temperatures during some periods. The US Fish and Wildlife Service’s Stream Network Temperature Model (SNTEMP) was applied to a 31-km segment of the river using readily available stream geometry and hydrological and meteorological data. The calibrated model produced satisfactory water temperature predictions (R2=0.88,P3/sec would be needed to maintain suitable summer temperatures throughout most of the study area. Such flows would be especially beneficial during weekends when current irrigation patterns reduce flows. The model indicated that increasing the riparian shade would result in little improvement in water temperatures but that decreasing the stream width would result in significant temperature reductions. Introduction of a more thermally tolerant redband trout (Oncorhynchus sp.), or smallmouth bass (Micropterus dolomieui) might prove beneficial to the fishery. Construction of deep pools for thermal refugia might also be helpful.

Impacts of climate change and climate extremes on major crops productivity in China at a global warming of 1.5 and 2.0 °C

NASA Astrophysics Data System (ADS)

Chen, Yi; Zhang, Zhao; Tao, Fulu

2018-05-01

A new temperature goal of holding the increase in global average temperature well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels has been established in the Paris Agreement, which calls for an understanding of climate risk under 1.5 and 2.0 °C warming scenarios. Here, we evaluated the effects of climate change on growth and productivity of three major crops (i.e. maize, wheat, rice) in China during 2106-2115 in warming scenarios of 1.5 and 2.0 °C using a method of ensemble simulation with well-validated Model to capture the Crop-Weather relationship over a Large Area (MCWLA) family crop models, their 10 sets of optimal crop model parameters and 70 climate projections from four global climate models. We presented the spatial patterns of changes in crop growth duration, crop yield, impacts of heat and drought stress, as well as crop yield variability and the probability of crop yield decrease. Results showed that climate change would have major negative impacts on crop production, particularly for wheat in north China, rice in south China and maize across the major cultivation areas, due to a decrease in crop growth duration and an increase in extreme events. By contrast, with moderate increases in temperature, solar radiation, precipitation and atmospheric CO2 concentration, agricultural climate resources such as light and thermal resources could be ameliorated, which would enhance canopy photosynthesis and consequently biomass accumulations and yields. The moderate climate change would slightly worsen the maize growth environment but would result in a much more appropriate growth environment for wheat and rice. As a result, wheat, rice and maize yields would change by +3.9 (+8.6), +4.1 (+9.4) and +0.2 % (-1.7 %), respectively, in a warming scenario of 1.5 °C (2.0 °C). In general, the warming scenarios would bring more opportunities than risks for crop development and food security in China. Moreover, although the variability of crop yield would increase from 1.5 °C warming to 2.0 °C warming, the probability of a crop yield decrease would decrease. Our findings highlight that the 2.0 °C warming scenario would be more suitable for crop production in China, but more attention should be paid to the expected increase in extreme event impacts.

Molecular dynamics simulations using temperature-enhanced essential dynamics replica exchange.

PubMed

Kubitzki, Marcus B; de Groot, Bert L

2007-06-15

Today's standard molecular dynamics simulations of moderately sized biomolecular systems at full atomic resolution are typically limited to the nanosecond timescale and therefore suffer from limited conformational sampling. Efficient ensemble-preserving algorithms like replica exchange (REX) may alleviate this problem somewhat but are still computationally prohibitive due to the large number of degrees of freedom involved. Aiming at increased sampling efficiency, we present a novel simulation method combining the ideas of essential dynamics and REX. Unlike standard REX, in each replica only a selection of essential collective modes of a subsystem of interest (essential subspace) is coupled to a higher temperature, with the remainder of the system staying at a reference temperature, T(0). This selective excitation along with the replica framework permits efficient approximate ensemble-preserving conformational sampling and allows much larger temperature differences between replicas, thereby considerably enhancing sampling efficiency. Ensemble properties and sampling performance of the method are discussed using dialanine and guanylin test systems, with multi-microsecond molecular dynamics simulations of these test systems serving as references.

Magnetic loss, permeability, and anisotropy compensation in CoO-doped Mn-Zn ferrites

NASA Astrophysics Data System (ADS)

Beatrice, Cinzia; Dobák, Samuel; Tsakaloudi, Vasiliki; Ragusa, Carlo; Fiorillo, Fausto; Martino, Luca; Zaspalis, Vassilis

2018-04-01

Mn-Zn ferrite samples prepared by conventional solid state reaction method and sintering at 1325 °C were Co-enriched by addition of CoO up to 6000 ppm and characterized versus frequency (DC - 1GHz), peak polarization (2 mT - 200 mT), and temperature (23 °C - 120 °C). The magnetic losses at room temperature are observed to pass through a deep minimum value around 4000 ppm CoO at all polarizations values. This trend is smoothed out either by approaching the MHz range or by increasing the temperature. Conversely, the initial permeability attains its maximum value around the same CoO content, while showing moderate monotonical decrease with increasing CoO at the typical working temperatures of 80 - 100 °C. The energy losses, measured by a combination of fluxmetric and transmission line methods, are affected by the eddy currents, on the conventional 5 mm thick ring samples, only beyond a few MHz. Their assessment relies on the separation of rotational and domain wall processes, which can be done by analysis of the complex permeability and its frequency behavior. This permits one, in particular, to calculate the magnetic anisotropy and its dependence on CoO content and temperature and bring to light its decomposition into the host lattice and Co2+ temperature dependent contributions. The temperature and doping dependence of initial permeability and magnetic losses can in this way be qualitatively justified, without invoking the passage through zero value of the effective anisotropy constant upon doping.

Mechanism and Effect of Temperature on Variations in Antibiotic Resistance Genes during Anaerobic Digestion of Dairy Manure.

PubMed

Sun, Wei; Qian, Xun; Gu, Jie; Wang, Xiao-Juan; Duan, Man-Li

2016-07-22

Animal manure comprises an important reservoir for antibiotic resistance genes (ARGs), but the variation in ARGs during anaerobic digestion at various temperatures and its underlying mechanism remain unclear. Thus, we performed anaerobic digestion using dairy manure at three temperature levels (moderate: 20 °C, mesophilic: 35 °C, and thermophilic: 55 °C), to analyze the dynamics of ARGs and bacterial communities by quantitative PCR and 16S rRNA gene sequencing. We found that 8/10 detected ARGs declined and 5/10 decreased more than 1.0 log during thermophilic digestion, whereas only four and five ARGs decreased during moderate and mesophilic digestion, respectively. The changes in ARGs and bacterial communities were similar under the moderate and mesophilic treatments, but distinct from those in the thermophilic system. Potential pathogens such as Bacteroidetes, Proteobacteria, and Corynebacterium were removed by thermophilic digestion but not by moderate and mesophilic digestion. The bacterial community succession was the dominant mechanism that influenced the variation in ARGs and integrons during anaerobic digestion. Thermophilic digestion decreased the amount of mesophilic bacteria (Bacteroidetes and Proteobacteria) carrying ARGs. Anaerobic digestion generally decreased the abundance of integrons by eliminating the aerobic hosts of integrons (Actinomycetales and Bacilli). Thermophilic anaerobic digestion is recommended for the treatment and reuse of animal manure.

Mechanism and Effect of Temperature on Variations in Antibiotic Resistance Genes during Anaerobic Digestion of Dairy Manure

NASA Astrophysics Data System (ADS)

Sun, Wei; Qian, Xun; Gu, Jie; Wang, Xiao-Juan; Duan, Man-Li

2016-07-01

Animal manure comprises an important reservoir for antibiotic resistance genes (ARGs), but the variation in ARGs during anaerobic digestion at various temperatures and its underlying mechanism remain unclear. Thus, we performed anaerobic digestion using dairy manure at three temperature levels (moderate: 20 °C, mesophilic: 35 °C, and thermophilic: 55 °C), to analyze the dynamics of ARGs and bacterial communities by quantitative PCR and 16S rRNA gene sequencing. We found that 8/10 detected ARGs declined and 5/10 decreased more than 1.0 log during thermophilic digestion, whereas only four and five ARGs decreased during moderate and mesophilic digestion, respectively. The changes in ARGs and bacterial communities were similar under the moderate and mesophilic treatments, but distinct from those in the thermophilic system. Potential pathogens such as Bacteroidetes, Proteobacteria, and Corynebacterium were removed by thermophilic digestion but not by moderate and mesophilic digestion. The bacterial community succession was the dominant mechanism that influenced the variation in ARGs and integrons during anaerobic digestion. Thermophilic digestion decreased the amount of mesophilic bacteria (Bacteroidetes and Proteobacteria) carrying ARGs. Anaerobic digestion generally decreased the abundance of integrons by eliminating the aerobic hosts of integrons (Actinomycetales and Bacilli). Thermophilic anaerobic digestion is recommended for the treatment and reuse of animal manure.

Identification of miRNAs and their targets in wild tomato at moderately and acutely elevated temperatures by high-throughput sequencing and degradome analysis

PubMed Central

Zhou, Rong; Wang, Qian; Jiang, Fangling; Cao, Xue; Sun, Mintao; Liu, Min; Wu, Zhen

2016-01-01

MicroRNAs (miRNAs) are 19–24 nucleotide (nt) noncoding RNAs that play important roles in abiotic stress responses in plants. High temperatures have been the subject of considerable attention due to their negative effects on plant growth and development. Heat-responsive miRNAs have been identified in some plants. However, there have been no reports on the global identification of miRNAs and their targets in tomato at high temperatures, especially at different elevated temperatures. Here, three small-RNA libraries and three degradome libraries were constructed from the leaves of the heat-tolerant tomato at normal, moderately and acutely elevated temperatures (26/18 °C, 33/33 °C and 40/40 °C, respectively). Following high-throughput sequencing, 662 conserved and 97 novel miRNAs were identified in total with 469 conserved and 91 novel miRNAs shared in the three small-RNA libraries. Of these miRNAs, 96 and 150 miRNAs were responsive to the moderately and acutely elevated temperature, respectively. Following degradome sequencing, 349 sequences were identified as targets of 138 conserved miRNAs, and 13 sequences were identified as targets of eight novel miRNAs. The expression levels of seven miRNAs and six target genes obtained by quantitative real-time PCR (qRT-PCR) were largely consistent with the sequencing results. This study enriches the number of heat-responsive miRNAs and lays a foundation for the elucidation of the miRNA-mediated regulatory mechanism in tomatoes at elevated temperatures. PMID:27653374

Bending cyclic load test for crystalline silicon photovoltaic modules

NASA Astrophysics Data System (ADS)

Suzuki, Soh; Doi, Takuya; Masuda, Atsushi; Tanahashi, Tadanori

2018-02-01

The failures induced by thermomechanical fatigue within crystalline silicon photovoltaic modules are a common issue that can occur in any climate. In order to understand these failures, we confirmed the effects of compressive or tensile stresses (which were cyclically loaded on photovoltaic cells and cell interconnect ribbons) at subzero, moderate, and high temperatures. We found that cell cracks were induced predominantly at low temperatures, irrespective of the compression or tension applied to the cells, although the orientation of cell cracks was dependent on the stress applied. The fracture of cell interconnect ribbons was caused by cyclical compressive stress at moderate and high temperatures, and this failure was promoted by the elevation of temperature. On the basis of these results, the causes of these failures are comprehensively discussed in relation to the viscoelasticity of the encapsulant.

Effects of simulated Mars conditions on the survival and growth of Escherichia coli and Serratia liquefaciens.

PubMed

Berry, Bonnie J; Jenkins, David G; Schuerger, Andrew C

2010-04-01

Escherichia coli and Serratia liquefaciens, two bacterial spacecraft contaminants known to replicate under low atmospheric pressures of 2.5 kPa, were tested for growth and survival under simulated Mars conditions. Environmental stresses of high salinity, low temperature, and low pressure were screened alone and in combination for effects on bacterial survival and replication, and then cells were tested in Mars analog soils under simulated Mars conditions. Survival and replication of E. coli and S. liquefaciens cells in liquid medium were evaluated for 7 days under low temperatures (5, 10, 20, or 30 degrees C) with increasing concentrations (0, 5, 10, or 20%) of three salts (MgCl(2), MgSO(4), NaCl) reported to be present on the surface of Mars. Moderate to high growth rates were observed for E. coli and S. liquefaciens at 30 or 20 degrees C and in solutions with 0 or 5% salts. In contrast, cell densities of both species generally did not increase above initial inoculum levels under the highest salt concentrations (10 and 20%) and the four temperatures tested, with the exception that moderately higher cell densities were observed for both species at 10% MgSO(4) maintained at 20 or 30 degrees C. Growth rates of E. coli and S. liquefaciens in low salt concentrations were robust under all pressures (2.5, 10, or 101.3 kPa), exhibiting a general increase of up to 2.5 orders of magnitude above the initial inoculum levels of the assays. Vegetative E. coli cells were maintained in a Mars analog soil for 7 days under simulated Mars conditions that included temperatures between 20 and -50 degrees C for a day/night diurnal period, UVC irradiation (200 to 280 nm) at 3.6 W m(-2) for daytime operations (8 h), pressures held at a constant 0.71 kPa, and a gas composition that included the top five gases found in the martian atmosphere. Cell densities of E. coli failed to increase under simulated Mars conditions, and survival was reduced 1 to 2 orders of magnitude by the interactive effects of desiccation, UV irradiation, high salinity, and low pressure (in decreasing order of importance). Results suggest that E. coli may be able to survive, but not grow, in surficial soils on Mars.

Effects of baking on cyanidin-3-glucoside content and antioxidant properties of black and yellow soybean crackers.

PubMed

Slavin, Margaret; Lu, Yingjian; Kaplan, Nicholas; Yu, Liangli Lucy

2013-11-15

Black soybean is a potential functional food ingredient with high anthocyanin content, but the ability to maintain anthocyanin content under dry heat processing has not been reported. This study investigated the effects of soybean seed coat colour and baking time-temperature combinations on the extractable antioxidant properties of a soy cracker food model. Crackers prepared with black soybeans had significantly higher TPC, total isoflavones, and peroxyl, hydroxyl, and ABTS(+) radical scavenging abilities than their yellow counterparts, at all time-temperature combinations. Cyanidin-3-glucoside (C3G) was detected only in black soybean crackers, and all baking treatments significantly decreased C3G. The greatest losses occurred at the low temperature×long time and high temperature×short time, the smallest loss with moderate temperature×short/medium time. The high temperature treatment altered phenolic acid and isoflavone profiles; however, total isoflavones were unaffected. Overall results suggest that moderate baking temperature at minimal time may best preserve anthocyanin and other phenolics in baked black soybean crackers. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pressure and temperature dependence of the Ce valence and c -f hybridization gap in Ce T2In5(T =Co ,Rh ,Ir ) heavy-fermion superconductors

NASA Astrophysics Data System (ADS)

Yamaoka, H.; Yamamoto, Y.; Schwier, E. F.; Honda, F.; Zekko, Y.; Ohta, Y.; Lin, J.-F.; Nakatake, M.; Iwasawa, H.; Arita, M.; Shimada, K.; Hiraoka, N.; Ishii, H.; Tsuei, K.-D.; Mizuki, J.

2015-12-01

Pressure- and temperature-induced changes in the Ce valence and c -f hybridization of the Ce115 superconductors have been studied systematically. Resonant x-ray-emission spectroscopy indicated that the increase of the Ce valence with pressure was significant for CeCoIn5, and moderate for CeIr (In0.925Cd0.075)5 . We found no abrupt change of the Ce valence in the Kondo regime for CeIr (In0.925Cd0.075)5 , which suggests that valence fluctuations are unlikely to mediate the superconductivity in this material. X-ray-diffraction results were consistent with the pressure-induced change in the Ce valence. High-resolution photoelectron spectroscopy revealed a temperature-dependent reduction of the spectral intensity at the Fermi level, indicating enhanced c -f hybridization on cooling.

Analysis of laser shock experiments on precompressed samples using a quartz reference and application to warm dense hydrogen and helium

DOE PAGES

Brygoo, Stephanie; Millot, Marius; Loubeyre, Paul; ...

2015-11-16

Megabar (1 Mbar = 100 GPa) laser shocks on precompressed samples allow reaching unprecedented high densities and moderately high ~10 3–10 4 K temperatures. We describe in this paper a complete analysis framework for the velocimetry (VISAR) and pyrometry (SOP) data produced in these experiments. Since the precompression increases the initial density of both the sample of interest and the quartz reference for pressure-density, reflectivity, and temperature measurements, we describe analytical corrections based on available experimental data on warm dense silica and density-functional-theory based molecular dynamics computer simulations. Finally, using our improved analysis framework, we report a re-analysis of previouslymore » published data on warm dense hydrogen and helium, compare the newly inferred pressure, density, and temperature data with most advanced equation of state models and provide updated reflectivity values.« less

Catalytic autothermal reforming increases fuel cell flexibility

NASA Technical Reports Server (NTRS)

Flytzani-Stephanopoulos, M.; Voecks, G. E.

1981-01-01

Experimental results are presented for the autothermal reforming (ATR) of n-hexane, n-tetradecane, benzene and benzene solutions of naphthalene. The tests were run at atmospheric pressure and at moderately high reactant preheat temperatures in the 800-900 K range. Carbon formation lines were determined for paraffinic and aromatic liquids. Profiles were determined for axial bed temperature and composition. Space velocity efforts were assessed, and the locations and types of carbon were recorded. Significant reactive differences between hydrocarbons were identified. Carbon formation characteristics were hydrocarbon specific. The differing behavior of paraffinic and aromatic fuels with respect to their carbon formation may be important in explaining the narrow range of carbon-free operating conditions found in the ATR of number two fuel oil.

Structural changes of corn stover lignin during acid pretreatment.

PubMed

Moxley, Geoffrey; Gaspar, Armindo Ribeiro; Higgins, Don; Xu, Hui

2012-09-01

In this study, raw corn stover was subjected to dilute acid pretreatments over a range of severities under conditions similar to those identified by the National Renewable Energy Laboratory (NREL) in their techno-economic analysis of biochemical conversion of corn stover to ethanol. The pretreated corn stover then underwent enzymatic hydrolysis with yields above 70 % at moderate enzyme loading conditions. The enzyme exhausted lignin residues were characterized by ³¹P NMR spectroscopy and functional moieties quantified and correlated to enzymatic hydrolysis yields. Results from this study indicated that both xylan solubilization and lignin degradation are important for improving the enzyme accessibility and digestibility of dilute acid pretreated corn stover. At lower pretreatment temperatures, there is a good correlation between xylan solubilization and cellulose accessibility. At higher pretreatment temperatures, lignin degradation correlated better with cellulose accessibility, represented by the increase in phenolic groups. During acid pretreatment, the ratio of syringyl/guaiacyl functional groups also gradually changed from less than 1 to greater than 1 with the increase in pretreatment temperature. This implies that more syringyl units are released from lignin depolymerization of aryl ether linkages than guaiacyl units. The condensed phenolic units are also correlated with the increase in pretreatment temperature up to 180 °C, beyond which point condensation reactions may overtake the hydrolysis of aryl ether linkages as the dominant reactions of lignin, thus leading to decreased cellulose accessibility.

Influence of processing parameters on the characteristics of surface layers of low temperature plasma nitrocarburized AISI 630 martensitic stainless steel

NASA Astrophysics Data System (ADS)

Lee, Insup

2017-11-01

Plasma nitrocarburizing was performed on solution-treated AISI 630 martensitic precipitation hardening stainless steel samples with a gas mixture of H2, N2, and CH4 with changing temperature, discharge voltage and amount of CH4. When nitrocarburized with increasing temperature from 380 °C to 430 °C at fixed 25% N2 and 6% CH4, the thickness of expanded martensite (α'N) layer and surface hardness increased up to 10 μm and 1323 HV0.05, respectively but the corrosion resistance decreased. Though the increase of discharge voltage from 400 V to 600 V increased α'N layer thickness and surface hardness (up to 13 μm and 1491 HV0.05, respectively), the treated samples still showed very poor corrosion behavior. Thus, to further improve the corrosion resistance, the influence of variation of the amount of CH4 in the nitrocarburizing process was investigated. Increasing the CH4 percentage aided higher corrosion resistance, although it decreased the α'N layer thickness. The most appropriate conditions for moderate α'N layer thickness, high surface hardness and better corrosion resistance than the solution-treated bare sample were established, which is plasma nitrocarburizing at 400 °C with 400 V discharge voltage and containing 25% N2 and 4% CH4.

Temperature is the evil twin: effects of increased temperature and ocean acidification on reproduction in a reef fish.

PubMed

Miller, G M; Kroon, F J; Metcalfe, S; Mundayi, P L

2015-04-01

Reproduction in many organisms can be disrupted by changes to the physical environment, such as those predicted to occur during climate change. Marine organisms face the dual climate change threats of increasing temperature and ocean acidification, yet no studies have examined the potential interactive effects of these stressors on reproduction in marine fishes. We used a long-term experiment to test the interactive effects of increased temperature and CO2 on the reproductive performance of the anemonefish, Amphiprion melanopus. Adult breeding pairs were kept for 10 months at three temperatures (28.5°C [+0.0°C], 30.0°C [-1.5°C] and 31.5°C [+3.0°C]) cross-factored with three CO2 levels (a current-day control [417 µatm] and moderate [644 µatm] and high [1134 µatm]) treatments consistent with the range of CO2 projections for the year 2100. We recorded each egg clutch produced during the breeding season, the number of eggs laid per clutch, average egg size, fertilization success, survival to hatching, hatchling length, and yolk provisioning. Adult body condition, hepatosomatic index, gonadosomatic index, and plasma 17β-estradiol concentrations were measured at the end of the breeding season to determine the effect of prolonged exposure to increased temperature and elevated. CO2 on adults, and to examine potential physiological mechanisms for changes in reproduction. Temperature had by far the stronger influence on reproduction, with clear declines in reproduction occurring in the +1.5°C treatment and ceasing altogether in the +3.0°C treatment. In contrast, CO2 had a minimal effect on the majority of reproductive traits measured, but caused a decline in offspring quality in combination with elevated temperature. We detected no significant effect of temperature or Co2 on adult body condition or hepatosomatic index. Elevated temperature had a significant negative effect on plasma 17β-estradiol concentrations, suggesting that declines in reproduction with increasing temperature were due to the thermal sensitivity of reproductive hormones rather than a reduction in energy available for reproduction. Our results show that elevated temperature exerts a stronger influence than high CO2 on reproduction in A. melanopus. Understanding how these two environmental variables interact to affect the reproductive performance of marine organisms will be important for predicting the future impacts of climate change.

He implantation induced microstructure- and hardness-modification of the intermetallic γ-TiAl

NASA Astrophysics Data System (ADS)

Pouchon, Manuel A.; Chen, Jiachao; Hoffelner, Wolfgang

2009-05-01

TiAl is a well known high temperature material with good creep properties. It is investigated as a potential structural material for Generation IV high temperature gas cooled nuclear reactors. The tests are performed with the ABB-2 (Ti-rich TiAl with 2 at.% W) developed by ASEA Brown Boveri Ltd. (ABB). Thin samples are irradiated throughout with 24 MeV 4He2+ ions; the irradiated material is then investigated towards its microstructure and its hardness. The microstructure is studied by transmission electron microscopy and the hardness is investigated using a micro-hardness tester and a nano-indenter. Different effects can be identified. From room to moderate irradiation temperatures, the radiation induced hardening of the material slowly vanishes until the material completely recovers at about 943 K. Beyond this temperature, He-bubble formation seems to harden the material again, until beyond 1200 K a steep increase in hardening is detected. This effect can be correlated with bubbles being identified in the micrographs. The results are consistent and give strong indications to a microstructural development as a function of temperature.

Influence of temperature during grain filling on gluten viscoelastic properties and gluten protein composition.

PubMed

Koga, Shiori; Böcker, Ulrike; Moldestad, Anette; Tosi, Paola; Shewry, Peter R; Mosleth, Ellen F; Uhlen, Anne Kjersti

2016-01-15

The aim of this study was to investigate the effects of low to moderate temperatures on gluten functionality and gluten protein composition. Four spring wheat cultivars were grown in climate chambers with three temperature regimes (day/night temperatures of 13/10, 18/15 and 23/20 °C) during grain filling. The temperature strongly influenced grain weight and protein content. Gluten quality measured by maximum resistance to extension (Rmax ) was highest in three cultivars grown at 13 °C. Rmax was positively correlated with the proportion of sodium dodecyl sulfate-unextractable polymeric proteins (%UPP). The proportions of ω-gliadins and D-type low-molecular-weight glutenin subunits (LMW-GS) increased and the proportions of α- and γ-gliadins and B-type LMW-GS decreased with higher temperature, while the proportion of high-molecular-weight glutenin subunits (HMW-GS) was constant between temperatures. The cultivar Berserk had strong and constant Rmax between the different temperatures. Constant low temperature, even as low as 13 °C, had no negative effects on gluten quality. The observed variation in Rmax related to temperature could be explained more by %UPP than by changes in the proportions of HMW-GS or other gluten proteins. The four cultivars responded differently to temperature, as gluten from Berserk was stronger and more stable over a wide range of temperatures. © 2015 Society of Chemical Industry.

Effects of urban tree canopy loss on land surface temperature magnitude and timing

NASA Astrophysics Data System (ADS)

Elmes, Arthur; Rogan, John; Williams, Christopher; Ratick, Samuel; Nowak, David; Martin, Deborah

2017-06-01

Urban Tree Canopy (UTC) plays an important role in moderating the Surface Urban Heat Island (SUHI) effect, which poses threats to human health due to substantially increased temperatures relative to rural areas. UTC coverage is associated with reduced urban temperatures, and therefore benefits both human health and reducing energy use in cities. Measurement of this relationship relies on accurate, fine spatial resolution UTC mapping, and on time series analysis of Land Surface Temperatures (LST). The City of Worcester, Massachusetts underwent extensive UTC loss and gain during the relatively brief period from 2008 to 2015, providing a natural experiment to measure the UTC/LST relationship. This paper consists of two elements to this end. First, it presents methods to map UTC in urban and suburban locations at fine spatial resolution (∼0.5 m) using image segmentation of a fused Lidar/WorldView-2 dataset, in order to show UTC change over time. Second, the areas of UTC change are used to explore changes in LST magnitude and seasonal variability using a time series of all available Landsat data for the study area over the eight-year period from 2007 to 2015. Fractional UTC change per unit area was determined using fine resolution UTC maps for 2008, 2010, and 2015, covering the period of large-scale tree loss and subsequent planting. LST changes were measured across a series of net UTC change bins, providing a relationship between UTC net change and LST trend. LST was analyzed for both monotonic trends over time and changes to seasonal magnitude and timing, using Theil-Sen slopes and Seasonal Trend Analysis (STA), respectively. The largest magnitudes of UTC loss occurred in residential neighborhoods, causing increased exposure of impervious (road) and pervious (grass) surfaces. Net UTC loss showed higher monotonic increases in LST than persistence and gain areas. STA indicated that net UTC loss was associated greater difference between 2008 and 2015 seasonal temperature curves than persistence areas, and also larger peak LST values, with peak increases ranging from 1 to 6 °C. Timing of summer warm period was extended in UTC loss areas by up to 15 days. UTC gain provided moderate LST mitigation, with lower monotonic trends, lower peak temperatures, and smaller seasonal curve changes than both persistence and loss locations. This study shows that urban trees mitigate the magnitude and timing of the surface urban heat island effect, even in suburban areas with less proportional impervious coverage than the dense urban areas traditionally associated with SUHI. Trees can therefore be seen as an effective means of offsetting the energy-intensive urban heat island effect.

Exercise training improves sleep pattern and metabolic profile in elderly people in a time-dependent manner

PubMed Central

2011-01-01

Aging and physical inactivity are two factors that favors the development of cardiovascular disease, metabolic syndrome, obesity, diabetes, and sleep dysfunction. In contrast, the adoption a habitual of moderate exercise may present a non-pharmacological treatment alternative for sleep and metabolic disorders. We aimed to assess the effects of moderate exercise training on sleep quality and on the metabolic profile of elderly people with a sedentary lifestyle. Fourteen male sedentary, healthy, elderly volunteers performed moderate training for 60 minutes/day, 3 days/week for 24 wk at a work rate equivalent to the ventilatory aerobic threshold. The environment was kept at a temperature of 23 ± 2°C, with an air humidity 60 ± 5%. Blood and polysomnographs analysis were collected 3 times: at baseline (1 week before training began), 3 and 6 months (after 3 and 6 months of training). Training promoted increasing aerobic capacity (relative VO2, time and velocity to VO2max; p < 0.05), and reduced serum NEFA, and insulin concentrations as well as improved HOMA index (p < 0.05), and increased adiponectin levels (p < 0.05), after 3 months of training when compared with baseline data. The sleep parameters, awake time and REM sleep latency were decreased after 6 months exercise training (p < 0.05) in relation baseline values. Our results demonstrate that the moderate exercise training protocol improves the sleep profile in older people, but the metabolism adaptation does not persist. Suggesting that this population requires training strategy modifications as to ensure consistent alterations regarding metabolism. PMID:21733182

Effect of organic matter application on CP-MAS-13C-NMR spectra of humic acids from a brown soil

NASA Astrophysics Data System (ADS)

Dou, S.

2009-04-01

The humified SOM or humic substances (HS) composed of humic acid (HA), fulvic acid (FA) and humin (HM) represent the most microbially recalcitrant and stable reservoir of organic carbon in soil (Piccolo et al., 2004). OM applications can influence the amount and structural characteristics of HS(Dou et al., 2008). During the past few decades, there has been much research on HS, but their chemical structure is still not fully understood (Dong, 2006).CP-MAS-13C-NMR spectroscopy was considered as an effective method to study structures of HS without dissolving problem compared with liquid 13C-NMR (Conte et al., 1997; Dou et al., 2008). It can directly measure the carbon framework and reflect the nature of HS transformation after OM application (Spaccini et al., 2000). For that reason, this method was applied in this study. The objective of this paper was to clarify the effect of long term OM application on the changes of structural characteristics in HAs, which provided new information for improving soil fertility by OM application. The experiment was carried out on a brown soil (Paleudalf in USDA Soil Taxonomy) at Shenyang Agricultural University, Liaoning province, China (N41°48'-E123°25'). The experiment included 3 treatments: zero-treatment (CKbr), and two pig manure (PM) treatments (O1 and O2) at the rates of 0.9 t ha-1 and 1.8 t ha-1 of organic carbon, respectively. The samples of the HA fraction were extracted, separated and purified according to the method described by Dou et al. (1991). Elemental composition, Differential thermal analysis (DTA), -lgK value, FT-IR and CP-MAS- 13C-NMR of HAs were performed. Effects on the contents of orgaic carbon and its composition. The contents of TOC were from 8.77 g kg-1 to 12.25 g kg-1. The relative contents in TOC for WSS, HA, and FA were 6.87%, 14.2% and 19.8%. Comparing the CKbr, the contents of WSS, HA and FA for O1 and O2 increased, but relative contents of WSS and FA decreased. The content of the HA increased after OM application, which was consistent with other studies (Wang et al., 2001). The content of the WSS increased after the OM application indicating that the increase of labile organic carbon. The C/H mole ratio of the HS could reflect the degree of condensation (Dou et al., 1995). Effects on HA chemical and optical properties. The chemical and optical properties of HA were listed. The C/H ratios decreased after OM application, from 0.830 (CKbr) to 0.754 (O2). While △lgK increased, from 0.623 (CKbr) to 0.658 (O2). The HA structure tended to become simpler. The C/H ratio of the HA decreased after OM application. This indicates that OM application decreased the degree of condensation. The △lgK values can be used as the index of HA molecule complexity in the soil. If △lgK increased, the molecular structure becomes simpler. After OM application, △lgK increased indicating that the molecular structure became simpler. Effects on HA thermal properties. It could be seen that HA had exothermic peaks in moderate and high temperature regions. After OM application, heat (H2) of exothermic peak increased in moderate temperature region, while heat (H3) of exothermic peak decreased in high temperature region. The the heat ratio of exothermic peaks in high temperature region to moderate (H3/H2) decreased. From CKbr to O2, H3/H2 decreased from 4.31 to0.86. The HA had moderate and high temperature exothermic peaks. The heat of exothermic peaks in the moderate temperature region might show that aliphatic compounds decomposed and peripheral functional groups decarboxylated. The heat of the exothermic peaks in the high temperature region might show that the HA was oxidized completely and inter-aromatic structures in the molecule decomposed. The heat ratio of the high to moderate temperature exothermic regions (H3/H2) decreased significantly after PM application, indicating that the proportion of aromatic structure decreased and the HA molecular structure simplified. Effects on CP-MAS-13C-NMR spectrum of HA. The CP-MAS- 13C-NMR spectra of the HA were quite similar to each other. These spectra exhibited signals for alkyl (0~50 ppm), O-alkyl (50~110 ppm), aromatic (110~160 ppm) and carbonyl (160~200 ppm) regions. The signals in carbonyl C region concentrated between 172 ppm and 173 ppm, and with a small signal occurred in the region of 190~200 ppm, indicating that there was carbonyl C of carboxylic acid, ester and amide, but a little amount carbonyl C of ketonic compounds. In the region of aromatic C, the most obvious peaks were the absorption at 131~133 ppm and 114~117 ppm. The former was mainly the aromatic C substituted by -COOH or -COOMe and the unsubstituted aromatic meta to carbons bearing an oxygen or nitrogen atom; the latter was mainly the unsubstituted aromatic C ortho and para to carbons bearing an oxygen and nitrogen atom. There was a small peak at 152-154ppm, which was the signal of phenolic OH. The signal at 55~56 ppm was methoxyl C. The signals at 71~73 ppm were due to the -CH(OH)- in carbohydrate. The peak at 102~103 ppm was generally assigned to double oxygen-C in polysaccharide (possibly acetal). The maximum absorption at 30 ppm was the contribution of the polymethylene chain -(CH2)n- in saturated hydrocarbons (Wilson, 1981). After OM application, the contents of alkyl C and O-alkyl C increased and the contents of aromatic C and carbonxyl C except to 1986 decreased. Compared with 1986, the contents of O-alkyl C increased and the contents of alkyl C decreased for the same treatment CKbr and O2. Aromaticity decreased significantly in OM treatments, indicating that the OM decreased the content of aromatic C and was simplified the molecular structure. The relative content of O-alkyl C increased indicating that OM application increased the content of methoxyl C and -CH(OH)- in carbohydrate. Alkyl C was probably derived from compounds of plants with high resistance to degradation, such as cutin and suberin (Baldock et al., 1992; Preston, 1996), or from newly synthesized products from soil micro-organisms , which are likely to represent the most persistent fraction of stable OM (Baldock et al., 1990; Lichtfouse et al., 1998; Piccolo, 2002). The alkyl C increased after the OM applications, indicated by the increase of hydrophobic components content and aliphatic character. Compared with 1986, the contents of O-alkyl C increased and the contents of alkyl C decreased for the same treatment CKbr and O2, indcating that a simplification trend took place in the aliphatic fraction of HA molecular with cultivation time in the tested soil. Conclusions.We have found that:1) The contents of HAs increased after OM application;2) OM application increased the contents of alkyl C and O-alkyl C, and decreased the C/H ratio, aromaticity, and the H3/H2 ratio of the HA, which indicated that the HA structure tended to become simpler and more aliphatic. 3) The results obtained by CP-MAS- 13C-NMR spectroscopy were mainly corresponding with those obtained by chemical analysis, thermal analysis, optical properties and IR spectroscopy, which indicated that 13C-NMR spectroscopy had a potential in characterizing the structural changes of HA after long-term OM application into soils.

Interactions of mean body and local skin temperatures in the modulation of human forearm and calf blood flows: a three-dimensional description.

PubMed

Caldwell, Joanne N; Matsuda-Nakamura, Mayumi; Taylor, Nigel A S

2016-02-01

The inter-relationships between mean body and local skin temperatures have previously been established for controlling hand and foot blood flows. Since glabrous skin contains many arteriovenous anastomoses, it was important to repeat those experiments on non-glabrous regions using the same sample and experimental conditions. Mild hypothermia (mean body temperature 31.4 °C), normothermia (control: 36.0 °C) and moderate hyperthermia (38.3 °C) were induced and clamped (climate chamber and water-perfusion garment) in eight males. Within each condition, five localised thermal treatments (5, 15, 25, 33, 40 °C) were applied to the left forearm and right calf. Steady-state forearm and calf blood flows were measured (venous occlusion plethysmography) for each of the resulting 15 combinations of clamped mean body and local skin temperatures. Under the normothermic clamp, cutaneous blood flows averaged 4.2 mL 100 mL(-1) min(-1) (±0.28: forearm) and 5.4 mL 100 mL(-1) min(-1) (±0.27: calf). When mildly hypothermic, these segments were unresponsive to localised thermal stimuli, but tracked those changes when normothermic and moderately hyperthermic. For deep-body (oesophageal) temperature elevations, forearm blood flow increased by 5.1 mL 100 mL(-1) min(-1) °C(-1) (±0.9) relative to normothermia, while the calf was much less responsive: 3.3 mL 100 mL(-1) min(-1) °C(-1) (±1.5). Three-dimensional surfaces revealed a qualitative divergence in the control of calf blood flow, with vasoconstrictor tone apparently being released more gradually. These descriptions reinforce the importance of deep-tissue temperatures in controlling cutaneous perfusion, with this modulation being non-linear at the forearm and appearing linear for the calf.

Relationship between ambient temperature and frequency and severity of cardiovascular emergencies: A prospective observational study based on out-of-hospital care data.

PubMed

Hensel, Mario; Stuhr, Markus; Geppert, Daniel; Kersten, Jan F; Lorenz, Jürgen; Kerner, Thoralf

2017-02-01

To test the hypothesis that more cardiovascular emergencies occur at low rather than at high temperatures under moderate climatic conditions. This was a prospective observational study performed in a prehospital setting. Data from the Emergency Medical Service in Hamburg (Germany) and from the local weather station were evaluated over a 5-year period. Temperature data were matched with the associated rescue mission data. Lowess-Regression analysis was performed to assess the relationship between the temperature and the frequency of individual cardiovascular emergencies. In addition, three threshold-temperatures (0°C, 10°C, 20°C) were defined in order to determine the frequency of cardiovascular emergencies above and below each cut-off value. The severity of emergencies was assessed using the National Advisory Committee for Aeronautics (NACA) scoring system. A total of 35,390 cardiovascular emergencies were treated by Emergency Physicians. Transient Loss of Consciousness increased at high temperatures (above 20°C): +43% (95%-CI: [27%; 59%]). In contrast, Coronary Artery Disease +26% (95%-CI: [17%; 34%]), Cardiac Pulmonary Edema +21% (95%-CI: [14%; 27%]), Hypertensive Urgency +18% (95%-CI: [10%; 25%]) and Cerebrovascular Accident +17% (95%-CI: [8%; 24%]) increased at low temperatures, particularly below 10°C (significance level for all: p<0.001). No temperature-related effect was seen in Cardiac Arrhythmia and Pulmonary Embolism and no significant correlation was found between the severity of emergencies and temperature. Our findings suggest that some cardiovascular emergencies such as Coronary Artery Disease, Cardiac Pulmonary Edema, Hypertensive Urgency and Cerebrovascular Accident are more frequent in low temperatures even under mild climatic conditions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

High-Temperature Thermoelectric Properties of Perovskite-Type Pr0.9Sr0.1Mn1- x Fe x O3 (0 ≤ x ≤ 1)

NASA Astrophysics Data System (ADS)

Nakatsugawa, H.; Saito, M.; Okamoto, Y.

2017-05-01

Polycrystalline samples of Pr0.9Sr0.1Mn1- x Fe x O3 (0 ≤ x ≤ 1) have been synthesized using a conventional solid-state reaction method, and the crystal structure studied at room temperature. The magnetic susceptibility was measured from 5 K to 350 K. The electrical resistivity, Seebeck coefficient, and thermal conductivity were investigated as functions of temperature below 850 K. For all samples, the perovskite structure at room temperature exhibited orthorhombic Pbnm phase. While the Pr0.9Sr0.1MnO3 ( x = 0) sample exhibited ferromagnetic-like ground state below T C = 145 K (Curie temperature), the ferromagnetic transition temperature T C decreased with increasing x. The Seebeck coefficient of the samples with 0 ≤ x ≤ 0.8 decreased with increasing temperature because of double-exchange interaction of Mn ions. In fact, the carrier type for x = 0 changed from hole-like to electron-like behavior above 800 K. On the other hand, the samples with x ≥ 0.9 showed large positive Seebeck coefficient over the entire temperature range, indicating that the low-spin state of Fe ions dominated the electronic structure for this x range. In particular, the sample with x = 1 exhibited p-type thermoelectric properties with relatively high Seebeck coefficient, moderate electrical resistivity, and low thermal conductivity. Thus, the sample with x = 1 showed power factor of 20 μW m-1 K-2 at 850 K leading to ZT of 0.024 at this temperature, indicating that hole-doped perovskite-type iron oxide is a good candidate high-temperature thermoelectric p-type oxide.

Insights into thermoadaptation and the evolution of mesophily from the bacterial phylum Thermotogae.

PubMed

Pollo, Stephen M J; Zhaxybayeva, Olga; Nesbø, Camilla L

2015-09-01

Thermophiles are extremophiles that grow optimally at temperatures >45 °C. To survive and maintain function of their biological molecules, they have a suite of characteristics not found in organisms that grow at moderate temperature (mesophiles). At the cellular level, thermophiles have mechanisms for maintaining their membranes, nucleic acids, and other cellular structures. At the protein level, each of their proteins remains stable and retains activity at temperatures that would denature their mesophilic homologs. Conversely, cellular structures and proteins from thermophiles may not function optimally at moderate temperatures. These differences between thermophiles and mesophiles presumably present a barrier for evolutionary transitioning between the 2 lifestyles. Therefore, studying closely related thermophiles and mesophiles can help us determine how such lifestyle transitions may happen. The bacterial phylum Thermotogae contains hyperthermophiles, thermophiles, mesophiles, and organisms with temperature ranges wide enough to span both thermophilic and mesophilic temperatures. Genomic, proteomic, and physiological differences noted between other bacterial thermophiles and mesophiles are evident within the Thermotogae. We argue that the Thermotogae is an ideal group of organisms for understanding of the response to fluctuating temperature and of long-term evolutionary adaptation to a different growth temperature range.

Transtemporal ultrasound application potentially elevates brain temperature: results of an anthropomorphic skull model.

PubMed

Pfaffenberger, S; Vyskocil, E; Kollmann, C; Unger, E; Kaun, C; Kastl, S; Woeber, C; Nawratil, G; Huber, K; Maurer, G; Gottsauner-Wolf, M; Wojta, J

2013-02-01

Transtemporal sonothrombolysis is a tool for a more effective treatment in acute stroke patients. However, some reports revealed side effects, which might be potentially connected to temperature elevation. To gain better insight into cerebral temperature changes during transtemporal sonication, diagnostic and therapeutic ultrasound (US) applications were evaluated using an anthropomorphic skull model. The impact of diagnostic (PW-Doppler, 1.8-MHz, 0.11 W/cm², TIC 1.2) and therapeutic (1-MHz and 3-MHz, 0.07 - 0.71 W/cm², continuous and pulsed mode) US application on temperature changes was evaluated at the level of muscle/temporal bone (TB), TB/brain, brain and at the middle cerebral artery (MCA) using 4 miniature thermocouples along the US beam. Sonication lasted 120 minutes. Diagnostic ultrasound revealed a maximum temperature increase of 1.45°/0.60°/0.39°/0.41°C (muscle/TB, TB/brain, brain, MCA) after 120 minutes. Therapeutic-1-MHz ultrasound raised temperature by 4.33°/2.02°/1.05 °C/0.81°C (pulsed 1:20) and by 10.38°/4.95°/2.43°/2.08°C (pulsed 1:5) over 120 minutes. Therapeutic-3-MHz US raised temperature by 4.89°/2.56°/1.24/1.25°C (pulsed 1:20) and by 14.77°/6.59°/3.56°/2.86°C (pulsed 1:5) over 120 minutes, respectively. Continuous application of therapeutic US (1-MHz and 3-MHz) led to a temperature increase of 13.86°/3.63°/1.66°/1.48°C and 17.09°/4.28°/1.38/0.99°C within 3 minutes. Diagnostic PW-Doppler showed only a moderate temperature increase and can be considered as safe. Therapeutic sonication is very powerful in delivering energy so that even pulsed application modes resulted in significant and potentially harmful temperature increases. © Georg Thieme Verlag KG Stuttgart · New York.

Influence of environmental variables on diffusive greenhouse gas fluxes at hydroelectric reservoirs in Brazil.

PubMed

Rogério, J P; Santos, M A; Santos, E O

2013-11-01

For almost two decades, studies have been under way in Brazil, showing how hydroelectric reservoirs produce biogenic gases, mainly methane (CH4) and carbon dioxide (CO2), through the organic decomposition of flooded biomass. This somewhat complex phenomenon is due to a set of variables with differing levels of interdependence that directly or indirectly affect greenhouse gas (GHG) emissions. The purpose of this paper is to determine, through a statistical data analysis, the relation between CO2, CH4 diffusive fluxes and environmental variables at the Furnas, Itumbiara and Serra da Mesa hydroelectric reservoirs, located in the Cerrado biome on Brazil's high central plateau. The choice of this region was prompted by its importance in the national context, covering an area of some two million square kilometers, encompassing two major river basins (Paraná and Tocantins-Araguaia), with the largest installed power generation capacity in Brazil, together accounting for around 23% of Brazilian territory. This study shows that CH4 presented a moderate negative correlation between CO2 and depth. Additionally, a moderate positive correlation was noted for pH, water temperature and wind. The CO2 presented a moderate negative correlation for pH, wind speed, water temperature and air temperature. Additionally, a moderate positive correlation was noted for CO2 and water temperature. The complexity of the emission phenomenon is unlikely to occur through a simultaneous understanding of all the factors, due to difficulties in accessing and analyzing all the variables that have real, direct effects on GHG production and emission.

Altered embryonic development in northern bobwhite quail (Colinus virginianus) induced by pre-incubation oscillatory thermal stresses mimicking global warming predictions

PubMed Central

Reyna, Kelly S.

2017-01-01

Global warming is likely to alter reproductive success of ground-nesting birds that lay eggs normally left unattended for days or even weeks before actual parental incubation, especially in already warm climates. The native North American bobwhite quail (Colinus virginianus) is such a species, and pre-incubation quail eggs may experience temperatures ≥45°C. Yet, almost nothing is known about embryonic survival after such high pre-incubation temperatures. Freshly laid bobwhite quail eggs were exposed during a 12 day pre-incubation period to one of five thermal regimes: low oscillating temperatures (25–40°C, mean = 28.9°C), high oscillating temperatures (30–45°C, mean = 33.9°C), low constant temperatures (28.85°C), high constant temperatures (mean = 33.9°C), or commercially employed pre-incubation temperatures (20°C). After treatment, eggs were then incubated at a standard 37.5°C to determine subsequent effects on embryonic development rate, survival, water loss, hatching, and embryonic oxygen consumption. Both quantity of heating degree hours during pre-incubation and specific thermal regime (oscillating vs. non-oscillating) profoundly affected important aspects of embryo survival and indices of development and growth Pre-incubation quail eggs showed a remarkable tolerance to constant high temperatures (up to 45°C), surviving for 4.5±0.3 days of subsequent incubation, but high oscillating pre-incubation temperature increased embryo survival (mean survival 12.2±1.8 days) and led to more rapid development than high constant temperature (maximum 38.5°C), even though both groups experienced the same total heating degree-hours. Oxygen consumption was ~200–300 μl O2.egg.min-1 at hatching in all groups, and was not affected by pre-incubation conditions. Oscillating temperatures, which are the norm for pre-incubation quail eggs in their natural habitat, thus enhanced survival at higher temperatures. However, a 5°C increase in pre-incubation temperature, which equates to the predicted long-term increases of 5°C or more, nonetheless reduced hatching rate by approximately 50%. Thus, while pre-incubation bobwhite eggs may be resiliant to moderate oscillating temperature increases, global warming will likely severely impact wild bobwhite quail populations, especially in their strongholds in southern latitudes. PMID:28926597

Altered embryonic development in northern bobwhite quail (Colinus virginianus) induced by pre-incubation oscillatory thermal stresses mimicking global warming predictions.

PubMed

Reyna, Kelly S; Burggren, Warren W

2017-01-01

Global warming is likely to alter reproductive success of ground-nesting birds that lay eggs normally left unattended for days or even weeks before actual parental incubation, especially in already warm climates. The native North American bobwhite quail (Colinus virginianus) is such a species, and pre-incubation quail eggs may experience temperatures ≥45°C. Yet, almost nothing is known about embryonic survival after such high pre-incubation temperatures. Freshly laid bobwhite quail eggs were exposed during a 12 day pre-incubation period to one of five thermal regimes: low oscillating temperatures (25-40°C, mean = 28.9°C), high oscillating temperatures (30-45°C, mean = 33.9°C), low constant temperatures (28.85°C), high constant temperatures (mean = 33.9°C), or commercially employed pre-incubation temperatures (20°C). After treatment, eggs were then incubated at a standard 37.5°C to determine subsequent effects on embryonic development rate, survival, water loss, hatching, and embryonic oxygen consumption. Both quantity of heating degree hours during pre-incubation and specific thermal regime (oscillating vs. non-oscillating) profoundly affected important aspects of embryo survival and indices of development and growth Pre-incubation quail eggs showed a remarkable tolerance to constant high temperatures (up to 45°C), surviving for 4.5±0.3 days of subsequent incubation, but high oscillating pre-incubation temperature increased embryo survival (mean survival 12.2±1.8 days) and led to more rapid development than high constant temperature (maximum 38.5°C), even though both groups experienced the same total heating degree-hours. Oxygen consumption was ~200-300 μl O2.egg.min-1 at hatching in all groups, and was not affected by pre-incubation conditions. Oscillating temperatures, which are the norm for pre-incubation quail eggs in their natural habitat, thus enhanced survival at higher temperatures. However, a 5°C increase in pre-incubation temperature, which equates to the predicted long-term increases of 5°C or more, nonetheless reduced hatching rate by approximately 50%. Thus, while pre-incubation bobwhite eggs may be resiliant to moderate oscillating temperature increases, global warming will likely severely impact wild bobwhite quail populations, especially in their strongholds in southern latitudes.

Volatile compound profile of sous-vide cooked lamb loins at different temperature-time combinations.

PubMed

Roldán, Mar; Ruiz, Jorge; Del Pulgar, José Sánchez; Pérez-Palacios, Trinidad; Antequera, Teresa

2015-02-01

Lamb loins were subjected to sous-vide cooking at different combinations of temperature (60 and 80°C) and time (6 and 24h) to assess the effect on the volatile compound profile. Major chemical families in cooked samples were aliphatic hydrocarbons and aldehydes. The volatile compound profile in sous-vide cooked lamb loin was affected by the cooking temperature and time. Volatile compounds arising from lipid oxidation presented a high abundance in samples cooked at low or moderate cooking conditions (60°C for 6 and 24h, 80°C for 6h), while a more intense time and temperature combination (80°C for 24h) resulted on a higher concentration of volatile compounds arising from Strecker degradations of amino acids, as 2-methylpropanal and 3-methylbutanal. Therefore, sous-vide cooking at moderately high temperatures for long times would result in the formation of a stronger meaty flavor and roast notes in lamb meat. Copyright © 2014 Elsevier Ltd. All rights reserved.

A study of the relationship between microstructure and oxidation effects in nuclear graphite at very high temperatures

NASA Astrophysics Data System (ADS)

Lo, I.-Hsuan; Tzelepi, Athanasia; Patterson, Eann A.; Yeh, Tsung-Kuang

2018-04-01

Graphite is used in the cores of gas-cooled reactors as both the neutron moderator and a structural material, and traditional and novel graphite materials are being studied worldwide for applications in Generation IV reactors. In this study, the oxidation characteristics of petroleum-based IG-110 and pitch-based IG-430 graphite pellets in helium and air environments at temperatures ranging from 700 to 1600 °C were investigated. The oxidation rates and activation energies were determined based on mass loss measurements in a series of oxidation tests. The surface morphology was characterized by scanning electron microscopy. Although the thermal oxidation mechanism was previously considered to be the same for all temperatures higher than 1000 °C, the significant increases in oxidation rate observed at very high temperatures suggest that the oxidation behavior of the selected graphite materials at temperatures higher than 1200 °C is different. This work demonstrates that changes in surface morphology and in oxidation rate of the filler particles in the graphite materials are more prominent at temperatures above 1200 °C. Furthermore, possible intrinsic factors contributing to the oxidation of the two graphite materials at different temperature ranges are discussed taking account of the dominant role played by temperature.

A study on the effects of temperature and substrate structure on the templated two-phase film growth via a hybrid model

NASA Astrophysics Data System (ADS)

Lu, Xiao; Li, Jia; Zhu, Jian-Gang; Laughlin, David E.; Zhu, Jingxi

2018-06-01

Templated growth of two-phase thin films can achieve desirably ordered microstructures. In such cases, the microstructure of the growing films follows the topography of the template. By combining the Potts model Monte Carlo simulation and the "level set" method, an attempt was previously made to understand the physical mechanism behind the templated growth process. In the current work, this model is further used to study the effect of two parameters within the templated growth scenario, namely, the temperature and the geometric features of the template. The microstructure of the thin film grown with different lattice temperatures and domes is analyzed. It is found that within a moderate temperature range, the effect of geometric features took control of the ordering of the microstructure by its influence on the surface energy gradient. Interestingly, within this temperature range, as the temperature is increased, an ordered microstructure forms on a template without the optimal geometric features, which seems to be a result of competition between the kinetics and the thermodynamics during deposition. However, when the temperature was either above or below this temperature range, the template provided no guide to the whole deposition so that no ordered microstructure formed.

Elevation of cardiac troponin I during non-exertional heat-related illnesses in the context of a heatwave

PubMed Central

2010-01-01

Introduction The prognostic value of cardiac troponin I (cTnI) in patients having a heat-related illness during a heat wave has been poorly documented. Methods In a post hoc analysis, we evaluated 514 patients admitted to emergency departments during the August 2003 heat wave in Paris, having a core temperature >38.5°C and who had analysis of cTnI levels. cTnI was considered as normal, moderately elevated (abnormality threshold to 1.5 ng.mL-1), or severely elevated (>1.5 ng.mL-1). Patients were classified according to our previously described risk score (high, intermediate, and low-risk of death). Results Mean age was 84 ± 12 years, mean body temperature 40.3 ± 1.2°C. cTnI was moderately elevated in 165 (32%) and severely elevated in 97 (19%) patients. One-year survival was significantly decreased in patients with moderate or severe increase in cTnI (24 and 46% vs 58%, all P < 0.05). Using logistic regression, four independent variables were associated with an elevated cTnI: previous coronary artery disease, Glasgow coma scale <12, serum creatinine >120 μmol.L-1, and heart rate >110 bpm. Using Cox regression, only severely elevated cTnI was an independent prognostic factor (hazard ratio 1.93, 95% confidence interval 1.35 to 2.77) when risk score was taken into account. One-year survival was decreased in patients with elevated cTnI only in high risk patients (17 vs 31%, P = 0.04). Conclusions cTnI is frequently elevated in patients with non-exertional heat-related illnesses during a heat wave and is an independent risk factor only in high risk patients where severe increase (>1.5 ng.mL-1) indicates severe myocardial damage. PMID:20507603

The Effects of Temperature and Hydrostatic Pressure on Metal Toxicity: Insights into Toxicity in the Deep Sea.

PubMed

Brown, Alastair; Thatje, Sven; Hauton, Chris

2017-09-05

Mineral prospecting in the deep sea is increasing, promoting concern regarding potential ecotoxicological impacts on deep-sea fauna. Technological difficulties in assessing toxicity in deep-sea species has promoted interest in developing shallow-water ecotoxicological proxy species. However, it is unclear how the low temperature and high hydrostatic pressure prevalent in the deep sea affect toxicity, and whether adaptation to deep-sea environmental conditions moderates any effects of these factors. To address these uncertainties we assessed the effects of temperature and hydrostatic pressure on lethal and sublethal (respiration rate, antioxidant enzyme activity) toxicity in acute (96 h) copper and cadmium exposures, using the shallow-water ecophysiological model organism Palaemon varians. Low temperature reduced toxicity in both metals, but reduced cadmium toxicity significantly more. In contrast, elevated hydrostatic pressure increased copper toxicity, but did not affect cadmium toxicity. The synergistic interaction between copper and cadmium was not affected by low temperature, but high hydrostatic pressure significantly enhanced the synergism. Differential environmental effects on toxicity suggest different mechanisms of action for copper and cadmium, and highlight that mechanistic understanding of toxicity is fundamental to predicting environmental effects on toxicity. Although results infer that sensitivity to toxicants differs across biogeographic ranges, shallow-water species may be suitable ecotoxicological proxies for deep-sea species, dependent on adaptation to habitats with similar environmental variability.

Integration of Tibetan Plateau ice-core temperature records and the influence of atmospheric circulation on isotopic signals in the past century

NASA Astrophysics Data System (ADS)

Yang, Xiaoxin; Yao, Tandong; Joswiak, Daniel; Yao, Ping

2014-05-01

Temperature signals in ice-core δ18O on the Tibetan Plateau (TP), particularly in the central and southern parts, continue to be debated because of the large scale of atmospheric circulation. This study presents ten ice-core δ18O records at an annual resolution, with four (Malan, Muztagata, Guliya, and Dunde) in the northern, three (Puruogangri, Geladaindong, Tanggula) in the central and three (Noijin Kangsang, Dasuopu, East Rongbuk) in the southern TP. Integration shows commonly increasing trends in δ18O in the past century, featuring the largest one in the northern, a moderate one in the central and the smallest one in the southern TP, which are all consistent with ground-based measurements of temperature. The influence of atmospheric circulation on isotopic signals in the past century was discussed through the analysis of El Niño/Southern Oscillation (ENSO), and of possible connections between sea surface temperature (SST) and the different increasing trends in both ice-core δ18O and temperature. Particularly, El Niño and the corresponding warm Bay of Bengal (BOB) SST enhance the TP ice-core isotopic enrichment, while La Niña, or corresponding cold BOB SST, causes depletion. This thus suggests a potential for reconstructing the ENSO history from the TP ice-core δ18O.

Plasma Hsp72 (HSPA1A) and Hsp27 (HSPB1) expression under heat stress: influence of exercise intensity.

PubMed

Périard, Julien D; Ruell, Patricia; Caillaud, Corinne; Thompson, Martin W

2012-05-01

Extracellular heat-shock protein 72 (eHsp72) expression during exercise-heat stress is suggested to increase with the level of hyperthermia attained, independent of the rate of heat storage. This study examined the influence of exercise at various intensities to elucidate this relationship, and investigated the association between eHsp72 and eHsp27. Sixteen male subjects cycled to exhaustion at 60% and 75% of maximal oxygen uptake in hot conditions (40°C, 50% RH). Core temperature, heart rate, oxidative stress, and blood lactate and glucose levels were measured to determine the predictor variables associated with eHsp expression. At exhaustion, heart rate exceeded 96% of maximum in both conditions. Core temperature reached 39.7°C in the 60% trial (58.9 min) and 39.0°C in the 75% trial (27.2 min) (P < 0.001). The rate of rise in core temperature was 2.1°C h(-1) greater in the 75% trial than in the 60% trial (P < 0.001). A significant increase and correlation was observed between eHsp72 and eHsp27 concentrations at exhaustion (P < 0.005). eHsp72 was highly correlated with the core temperature attained (60% trial) and the rate of increase in core temperature (75% trial; P < 0.05). However, no common predictor variable was associated with the expression of both eHsps. The similarity in expression of eHsp72 and eHsp27 during moderate- and high-intensity exercise may relate to the duration (i.e., core temperature attained) and intensity (i.e., rate of increase in core temperature) of exercise. Thus, the immuno-inflammatory release of eHsp72 and eHsp27 in response to exercise in the heat may be duration and intensity dependent.

Effects of chronic environmental cold on growth, health, and select metabolic and immunologic responses of preruminant calves.

PubMed

Nonnecke, B J; Foote, M R; Miller, B L; Fowler, M; Johnson, T E; Horst, R L

2009-12-01

The physiological response of the preruminant calf to sustained exposure to moderate cold has not been studied extensively. Effects of cold on growth performance and health of preruminant calves as well as functional measures of energy metabolism, fat-soluble vitamin, and immune responsiveness were evaluated in the present study. Calves, 3 to 10 d of age, were assigned randomly to cold (n = 14) or warm (n = 15) indoor environments. Temperatures in the cold environment averaged 4.7 degrees C during the study. Frequent wetting of the environment and the calves was used to augment effects of the cold environment. Temperatures in the warm environment averaged 15.5 degrees C during the study. There was no attempt to increase the humidity in the warm environment. Preventative medications or vaccinations that might influence disease resistance were not administered. Nonmedicated milk replacer (20% crude protein and 20% fat fed at 0.45 kg/d) and a nonmedicated starter grain fed ad libitum were fed to all calves. Relative humidity was, on average, almost 10% higher in the cold environment. Warm-environment calves were moderately healthier (i.e., lower respiratory scores) and required less antibiotics. Scour scores, days scouring, and electrolyte costs, however, were unaffected by environmental temperature. Growth rates were comparable in warm and cold environments, although cold-environment calves consumed more starter grain and had lower blood glucose and higher blood nonesterified fatty acid concentrations. The nonesterified fatty acid and glucose values for cold-stressed calves, however, did not differ sufficiently from normal values to categorize these calves as being in a state of negative-energy balance. Levels of fat-soluble vitamin, antibody, tumor necrosis factor-alpha, and haptoglobin were unaffected by sustained exposure to moderate cold. These results support the contention that successful adaptation of the dairy calf to cold is dependent upon the availability of adequate nutrition.

Responses of wind erosion to climate-induced vegetation changes on the Colorado Plateau.

PubMed

Munson, Seth M; Belnap, Jayne; Okin, Gregory S

2011-03-08

Projected increases in aridity throughout the southwestern United States due to anthropogenic climate change will likely cause reductions in perennial vegetation cover, which leaves soil surfaces exposed to erosion. Accelerated rates of dust emission from wind erosion have large implications for ecosystems and human well-being, yet there is poor understanding of the sources and magnitude of dust emission in a hotter and drier climate. Here we use a two-stage approach to compare the susceptibility of grasslands and three different shrublands to wind erosion on the Colorado Plateau and demonstrate how climate can indirectly moderate the magnitude of aeolian sediment flux through different responses of dominant plants in these communities. First, using results from 20 y of vegetation monitoring, we found perennial grass cover in grasslands declined with increasing mean annual temperature in the previous year, whereas shrub cover in shrublands either showed no change or declined as temperature increased, depending on the species. Second, we used these vegetation monitoring results and measurements of soil stability as inputs into a field-validated wind erosion model and found that declines in perennial vegetation cover coupled with disturbance to biological soil crust resulted in an exponential increase in modeled aeolian sediment flux. Thus the effects of increased temperature on perennial plant cover and the correlation of declining plant cover with increased aeolian flux strongly suggest that sustained drought conditions across the southwest will accelerate the likelihood of dust production in the future on disturbed soil surfaces.

Climatic warming increases winter wheat yield but reduces grain nitrogen concentration in east China.

PubMed

Tian, Yunlu; Zheng, Chengyan; Chen, Jin; Chen, Changqing; Deng, Aixing; Song, Zhenwei; Zhang, Baoming; Zhang, Weijian

2014-01-01

Climatic warming is often predicted to reduce wheat yield and grain quality in China. However, direct evidence is still lacking. We conducted a three-year experiment with a Free Air Temperature Increase (FATI) facility to examine the responses of winter wheat growth and plant N accumulation to a moderate temperature increase of 1.5°C predicted to prevail by 2050 in East China. Three warming treatments (AW: all-day warming; DW: daytime warming; NW: nighttime warming) were applied for an entire growth period. Consistent warming effects on wheat plant were recorded across the experimental years. An increase of ca. 1.5°C in daily, daytime and nighttime mean temperatures shortened the length of pre-anthesis period averagely by 12.7, 8.3 and 10.7 d (P<0.05), respectively, but had no significant impact on the length of the post-anthesis period. Warming did not significantly alter the aboveground biomass production, but the grain yield was 16.3, 18.1 and 19.6% (P<0.05) higher in the AW, DW and NW plots than the non-warmed plot, respectively. Warming also significantly increased plant N uptake and total biomass N accumulation. However, warming significantly reduced grain N concentrations while increased N concentrations in the leaves and stems. Together, our results demonstrate differential impacts of warming on the depositions of grain starch and protein, highlighting the needs to further understand the mechanisms that underlie warming impacts on plant C and N metabolism in wheat.

Responses of wind erosion to climate-induced vegetation changes on the Colorado Plateau

USGS Publications Warehouse

Munson, Seth M.; Belnap, Jayne; Okin, Gregory S.

2011-01-01

Projected increases in aridity throughout the southwestern United States due to anthropogenic climate change will likely cause reductions in perennial vegetation cover, which leaves soil surfaces exposed to erosion. Accelerated rates of dust emission from wind erosion have large implications for ecosystems and human well-being, yet there is poor understanding of the sources and magnitude of dust emission in a hotter and drier climate. Here we use a two-stage approach to compare the susceptibility of grasslands and three different shrublands to wind erosion on the Colorado Plateau and demonstrate how climate can indirectly moderate the magnitude of aeolian sediment flux through different responses of dominant plants in these communities. First, using results from 20 y of vegetation monitoring, we found perennial grass cover in grasslands declined with increasing mean annual temperature in the previous year, whereas shrub cover in shrublands either showed no change or declined as temperature increased, depending on the species. Second, we used these vegetation monitoring results and measurements of soil stability as inputs into a field-validated wind erosion model and found that declines in perennial vegetation cover coupled with disturbance to biological soil crust resulted in an exponential increase in modeled aeolian sediment flux. Thus the effects of increased temperature on perennial plant cover and the correlation of declining plant cover with increased aeolian flux strongly suggest that sustained drought conditions across the southwest will accelerate the likelihood of dust production in the future on disturbed soil surfaces.

Combined Hyperbaric Oxygen Partial Pressure at 1.4 Bar with Infrared Radiation: A Useful Tool To Improve Tissue Hypoxemia?

PubMed

Dünnwald, Tobias; Held, Julia; Balan, Petru; Pecher, Otto; Zeiger, Thomas; Hartig, Frank; Mur, Erich; Weiss, Günter; Schobersberger, Wolfgang

2018-06-13

Tissue hypoxia contributes to the pathogenesis of several acute and chronic diseases. Hyperbaric oxygen therapy (HBO) and whole-body warming using low-temperature infrared technology (LIT) are techniques that might improve hypoxemia. Combining HBO and LIT as hyperbaric oxygen therapy combined with low-temperature infrared radiation (HBOIR) might be an approach that results in positive synergistic effects on oxygenation. LIT increases blood flow and could reduce HBO-induced vasoconstriction, and hyperoxia could compensate for the increased metabolic oxygen requirements mediated by LIT. Both LIT and HBO increase the oxygen diffusion distance in the tissues. HBOIR at 0.5 bar has been shown to be safe and feasible. However, physiological responses and the safety of HBOIR at an increased oxygen (O2) partial pressure of 1.4 bar or 2.4 atmospheres absolute (ATA) still need to be determined. The hope is that should HBOIR at an increased oxygen partial pressure of 1.4 bar be safe, future studies to examine its efficacy in patients with clinical conditions, which include peripheral arterial disease (PAD) or wound healing disorders, will follow. The results of pilot studies have shown that HBOIR at an overload pressure is safe and well tolerated in healthy participants but can generate moderate cardiovascular changes and an increase in body temperature. From the findings of this pilot study, due to its potential synergistic effects, HBOIR could be a promising tool for the treatment of human diseases associated with hypoxemia.

Responses of wind erosion to climate-induced vegetation changes on the Colorado Plateau

PubMed Central

Munson, Seth M.; Belnap, Jayne; Okin, Gregory S.

2011-01-01

Projected increases in aridity throughout the southwestern United States due to anthropogenic climate change will likely cause reductions in perennial vegetation cover, which leaves soil surfaces exposed to erosion. Accelerated rates of dust emission from wind erosion have large implications for ecosystems and human well-being, yet there is poor understanding of the sources and magnitude of dust emission in a hotter and drier climate. Here we use a two-stage approach to compare the susceptibility of grasslands and three different shrublands to wind erosion on the Colorado Plateau and demonstrate how climate can indirectly moderate the magnitude of aeolian sediment flux through different responses of dominant plants in these communities. First, using results from 20 y of vegetation monitoring, we found perennial grass cover in grasslands declined with increasing mean annual temperature in the previous year, whereas shrub cover in shrublands either showed no change or declined as temperature increased, depending on the species. Second, we used these vegetation monitoring results and measurements of soil stability as inputs into a field-validated wind erosion model and found that declines in perennial vegetation cover coupled with disturbance to biological soil crust resulted in an exponential increase in modeled aeolian sediment flux. Thus the effects of increased temperature on perennial plant cover and the correlation of declining plant cover with increased aeolian flux strongly suggest that sustained drought conditions across the southwest will accelerate the likelihood of dust production in the future on disturbed soil surfaces. PMID:21368143

Daily Scheduled High Fat Meals Moderately Entrain Behavioral Anticipatory Activity, Body Temperature, and Hypothalamic c-Fos Activation

PubMed Central

Gallardo, Christian M.; Gunapala, Keith M.; King, Oliver D.; Steele, Andrew D.

2012-01-01

When fed in restricted amounts, rodents show robust activity in the hours preceding expected meal delivery. This process, termed food anticipatory activity (FAA), is independent of the light-entrained clock, the suprachiasmatic nucleus, yet beyond this basic observation there is little agreement on the neuronal underpinnings of FAA. One complication in studying FAA using a calorie restriction model is that much of the brain is activated in response to this strong hunger signal. Thus, daily timed access to palatable meals in the presence of continuous access to standard chow has been employed as a model to study FAA in rats. In order to exploit the extensive genetic resources available in the murine system we extended this model to mice, which will anticipate rodent high fat diet but not chocolate or other sweet daily meals (Hsu, Patton, Mistlberger, and Steele; 2010, PLoS ONE e12903). In this study we test additional fatty meals, including peanut butter and cheese, both of which induced modest FAA. Measurement of core body temperature revealed a moderate preprandial increase in temperature in mice fed high fat diet but entrainment due to handling complicated interpretation of these results. Finally, we examined activation patterns of neurons by immunostaining for the immediate early gene c-Fos and observed a modest amount of entrainment of gene expression in the hypothalamus of mice fed a daily fatty palatable meal. PMID:22815954

Effect of cold indoor environment on physical performance of older women living in the community.

PubMed

Lindemann, Ulrich; Oksa, Juha; Skelton, Dawn A; Beyer, Nina; Klenk, Jochen; Zscheile, Julia; Becker, Clemens

2014-07-01

the effects of cold on older persons' body and mind are not well documented, but with an increased number of older people with decreasing physical performance, these possible effects need to be understood. to investigate the effect of cold indoor environment on physical performance of older women. cross-sectional experimental study with two test conditions. movement laboratory in a climate chamber. eighty-eight community-dwelling, cognitively unimpaired older women (mean age 78 years). participants were exposed to moderately cold (15°C) and warm/normal (25°C) temperature in a climate chamber in random order with an interval of 1 week. The assessment protocol included leg extensor power (Nottingham Power Rig), sit-to-stand performance velocity (linear encoder), gait speed, walk-ratio (i.e. step length/cadence on an instrumented walk way), maximal quadriceps and hand grip strength. physical performance was lower in 15°C room temperature compared with 25°C room temperature for leg extensor power (P < 0.0001), sit-to-stand performance velocity (P < 0.0001), gait speed (P < 0.0001), walk-ratio (P = 0.016) and maximal quadriceps strength (P = 0.015), but not for hand grip strength. in healthy older women a moderately cold indoor environment decreased important physical performance measures necessary for independent living. © The Author 2014. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

River discharge as a major driving force on spatial and temporal variations in zooplankton biomass and community structure in the Godavari estuary India.

PubMed

Venkataramana, V; Sarma, V V S S; Matta Reddy, Alavala

2017-08-28

Variability in horizontal zooplankton biomass distribution was investigated over 13 months in the Godavari estuary, along with physical (river discharge, temperature, salinity), chemical (nutrients, particulate organic matter), biological (phytoplankton biomass), and geological (suspended matter) properties to examine the influencing factors on their spatial and temporal variabilities. The entire estuary was filled with freshwater during peak discharge period and salinity near zero, increased to ~ 34 psu during dry period with relatively high nutrient levels during former than the latter period. Due to low flushing time (< 1 day) and high suspended load (> 500 mg L -1 ) during peak discharge period, picoplankton (cyanophyceae) contributed significantly to the phytoplankton biomass (Chl-a) whereas microplankton and nanoplankton (bacillariophyceae, and chlorophyceae) during moderate and mostly microplankton during dry period. Zooplankton biomass was the lowest during peak discharge period and increased during moderate followed by dry period. The zooplankton abundance was controlled by dead organic matter during peak discharge period, while both phytoplankton biomass and dead organic matter during moderate discharge and mostly phytoplankton biomass during dry period. This study suggests that significant modification of physico-chemical properties by river discharge led to changes in phytoplankton composition and dead organic matter concentrations that alters biomass, abundance, and composition of zooplankton in the Godavari estuary.

Experimental investigations of the minimum ignition energy and the minimum ignition temperature of inert and combustible dust cloud mixtures.

PubMed

Addai, Emmanuel Kwasi; Gabel, Dieter; Krause, Ulrich

2016-04-15

The risks associated with dust explosions still exist in industries that either process or handle combustible dust. This explosion risk could be prevented or mitigated by applying the principle of inherent safety (moderation). This is achieved by adding an inert material to a highly combustible material in order to decrease the ignition sensitivity of the combustible dust. The presented paper deals with the experimental investigation of the influence of adding an inert dust on the minimum ignition energy and the minimum ignition temperature of the combustible/inert dust mixtures. The experimental investigation was done in two laboratory scale equipment: the Hartmann apparatus and the Godbert-Greenwald furnace for the minimum ignition energy and the minimum ignition temperature test respectively. This was achieved by mixing various amounts of three inert materials (magnesium oxide, ammonium sulphate and sand) and six combustible dusts (brown coal, lycopodium, toner, niacin, corn starch and high density polyethylene). Generally, increasing the inert materials concentration increases the minimum ignition energy as well as the minimum ignition temperatures until a threshold is reached where no ignition was obtained. The permissible range for the inert mixture to minimize the ignition risk lies between 60 to 80%. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of predicted climage change elements on Z. ...

EPA Pesticide Factsheets

Global climate change (GCC) is expected to have pronounced impacts on estuarine and marine habitats including sea level rise, increased storm intensity, increased air and water temperatures, changes in upwelling dynamics and ocean acidification. All of these elements are likely to impact the growth and potential distribution of the non-indigenous seagrass Zostera japonica both within the State of Washington and within the region. Understanding how Z. japonica will respond to GCC requires a thorough understanding of plant physiology and predictions of GCC effects. Furthermore, Washington State is proposing to list Z. japonica as a “noxious weed” which will allow the state to use herbicide controls for management. We present data from manipulative experiments designed to better understand how Z. japonica photosynthetic physiology responds to temperature, salinity and light. We found that Z. japonica is well adapted to moderate temperatures and salinity with maximum photosynthesis of salinity of 20. The Coos Bay population had greater Pmax and saturation irradiance (Ik) than the Padilla bay population (p < 0.001) and tolerates daily exposure to both freshwater and marine water, suggesting that this population tolerates fairly extreme environmental fluctuations. Extreme temperatures (35 °C) were generally lethal to Z. japonica populations from Padilla, Coos and Yaquina Bays. High salinity (35) had lower mortality than either salinity of 5 or 20 (p = 0.0

Impact of the Dubai Coastline Intensive Urbanization on the Atmosphere Employing MODIS Data (2001-2014)

NASA Astrophysics Data System (ADS)

Elhacham, Emily; Alpert, Pinhas

2017-04-01

Over the last 20 years Dubai landscape has dramatically changed - artificial islands have been constructed as well as residential and industrial facilities along with roads systems. This rapid and massive construction placed Dubai urban growth rate at the top of the global list. Here, we investigate the impact of those constructions on the local atmosphere, both in land and sea based on MODIS data. It was found that, over the tested time period, temperature decreases and albedo increases were observed in the sea area of the artificial islands. In land, albedo decreases along with temperature increases of up to 2C were observed in the areas along the coast where intensive constructions occurred. In addition, the coast of Dubai was found to have urban heat island characteristics, where the urban center point at Deira area exhibits higher temperature than surrounding points along the coast. Nonetheless, the largest temperature trends were observed in the coastal area in between Palm Jumeirah and Palm Jebel Ali, where massive construction was performed during the tested time frame. Reference: E.Elhacham and P. Alpert ,"Impact of coastline-intensive anthropogenic activities on the atmosphere from moderate resolution imaging spectroradiometer (MODIS) data in Dubai (2001-2014)", Earth's Future, 4, 2016.

Land surface temperature as potential indicator of burn severity in forest Mediterranean ecosystems

NASA Astrophysics Data System (ADS)

Quintano, C.; Fernández-Manso, A.; Calvo, L.; Marcos, E.; Valbuena, L.

2015-04-01

Forest fires are one of the most important causes of environmental alteration in Mediterranean countries. Discrimination of different degrees of burn severity is critical for improving management of fire-affected areas. This paper aims to evaluate the usefulness of land surface temperature (LST) as potential indicator of burn severity. We used a large convention-dominated wildfire, which occurred on 19-21 September, 2012 in Northwestern Spain. From this area, a 1-year series of six LST images were generated from Landsat 7 Enhanced Thematic Mapper (ETM+) data using a single channel algorithm. Further, the Composite Burn Index (CBI) was measured in 111 field plots to identify the burn severity level (low, moderate, and high). Evaluation of the potential relationship between post-fire LST and ground measured CBI was performed by both correlation analysis and regression models. Correlation coefficients were higher in the immediate post-fire LST images, but decreased during the fall of 2012 and increased again with a second maximum value in summer, 2013. A linear regression model between post-fire LST and CBI allowed us to represent spatially predicted CBI (R-squaredadj > 85%). After performing an analysis of variance (ANOVA) between post-fire LST and CBI, a Fisher's least significant difference test determined that two burn severity levels (low-moderate and high) could be statistically distinguished. The identification of such burn severity levels is sufficient and useful to forest managers. We conclude that summer post-fire LST from moderate resolution satellite data may be considered as a valuable indicator of burn severity for large fires in Mediterranean forest ecosytems.

Conformation transitions of a single polyelectrolyte chain in a poor solvent: a replica-exchange lattice Monte-Carlo study.

PubMed

Wang, Lang; Wang, Zheng; Jiang, Run; Yin, Yuhua; Li, Baohui

2017-03-15

The thermodynamic behaviors of a strongly charged polyelectrolyte chain in a poor solvent are studied using replica-exchange Monte-Carlo simulations on a lattice model, focusing on the effects of finite chain length and the solvent quality on the chain conformation and conformation transitions. The neutralizing counterions and solvent molecules are considered explicitly. The thermodynamic quantities that vary continuously with temperature over a wide range are computed using the multiple histogram reweighting method. Our results suggest that the strength of the short-range hydrophobic interaction, the chain length, and the temperature of the system, characterized by ε, N, and T, respectively, are important parameters that control the conformations of a charged chain. When ε is moderate, the competition between the electrostatic energy and the short-range hydrophobic interaction leads to rich conformations and conformation transitions for a longer chain with a fixed length. Our results have unambiguously demonstrated the stability of the n-pearl-necklace structures, where n has a maximum value and decreases with decreasing temperature. The maximum n value increases with increasing chain length. Our results have also demonstrated the first-order nature of the conformation transitions between the m-pearl and the (m-1)-pearl necklaces. With the increase of ε, the transition temperature increases and the first-order feature becomes more pronounced. It is deduced that at the thermodynamic limit of infinitely long chain length, the conformational transitions between the m-pearl and the (m-1)-pearl necklaces may remain first order when ε > 0 and m = 2 or 3. Pearl-necklace conformations cannot be observed when either ε is too large or N is too small. To observe a pearl-necklace conformation, the T value needs to be carefully chosen for simulations performed at only a single temperature.

Thermoelectric Power Generation from Lanthanum Strontium Titanium Oxide at Room Temperature through the Addition of Graphene.

PubMed

Lin, Yue; Norman, Colin; Srivastava, Deepanshu; Azough, Feridoon; Wang, Li; Robbins, Mark; Simpson, Kevin; Freer, Robert; Kinloch, Ian A

2015-07-29

The applications of strontium titanium oxide based thermoelectric materials are currently limited by their high operating temperatures of >700 °C. Herein, we show that the thermal operating window of lanthanum strontium titanium oxide (LSTO) can be reduced to room temperature by the addition of a small amount of graphene. This increase in operating performance will enable future applications such as generators in vehicles and other sectors. The LSTO composites incorporated one percent or less of graphene and were sintered under an argon/hydrogen atmosphere. The resultant materials were reduced and possessed a multiphase structure with nanosized grains. The thermal conductivity of the nanocomposites decreased upon the addition of graphene, whereas the electrical conductivity and power factor both increased significantly. These factors, together with a moderate Seebeck coefficient, meant that a high power factor of ∼2500 μWm(-1)K(-2) was reached at room temperature at a loading of 0.6 wt % graphene. The highest thermoelectric figure of merit (ZT) was achieved when 0.6 wt % graphene was added (ZT = 0.42 at room temperature and 0.36 at 750 °C), with >280% enhancement compared to that of pure LSTO. A preliminary 7-couple device was produced using bismuth strontium cobalt oxide/graphene-LSTO pucks. This device had a Seebeck coefficient of ∼1500 μV/K and an open voltage of 600 mV at a mean temperature of 219 °C.

Effect of the Temperature of the Moderator on the Velocity Distribution of Neutrons with Numerical Calculations for H as Moderator

DOE R&D Accomplishments Database

Wigner, E. P.; Wilkins, J. E. Jr.

1944-09-14

In this paper we set up an integral equation governing the energy distribution of neutrons that are being slowed down uniformly throughout the entire space by a uniformly distributed moderator whose atoms are in motion with a Maxwellian distribution of velocities. The effects of chemical binding and crystal reflection are ignored. When the moderator is hydrogen, the integral equation is reduced to a differential equation and solved by numerical methods. In this manner we obtain a refinement of the dv/v{sup 2} law. (auth)

[Tongue base reduction with radiofrequency energy in sleep apnea].

PubMed

Stuck, B A; Maurer, J T; Hörmann, K

2001-07-01

Tongue base reduction with temperature-controlled radiofrequency for the treatment of obstructive sleep apnea syndrome is a minimally invasive technique. Repeated application leads to a progressive shrinking of the tissue. In our study, we summarize the experiences gained from 100 tongue base reductions and compare them with the pilot study that was recently published. An intensified treatment scheme was used with higher amounts of energy applied per treatment session. Visual analogue scales were used for the assessment of postoperative pain and functional parameters. Regular follow-up visits were scheduled to evaluate postoperative complications. Postoperative pain was mostly mild or moderate. Paraoperative complications were not observed. The overall rate for postoperative complications was 8%, with 2% mild and 5% moderate complications. One severe complication--a tongue base abscedation--was observed. Using para- and postoperative antibiotic prophylaxis reduced the rate of complications. Functional parameters such as taste or swallowing were not affected. Our results underline the safety of the procedure and demonstrate the minimal para- and postoperative morbidity. The increased amount of energy applied per session has not led to an increase in postoperative morbidity.

STEAM FORMING NEUTRONIC REACTOR AND METHOD OF OPERATING IT

DOEpatents

Untermyer, S.

1960-05-10

The heterogeneous reactor is liquid moderated and cooled by a steam forming coolant and is designed to produce steam from the coolant directly within the active portion of the reactor while avoiding the formation of bubbles in the liquid moderator. This reactor achieves inherent stability as a result of increased neutron leakage and increased neutron resonance absorption in the U/sup 238/ fuel with the formation of bubbles. The invention produces certain conditions under which the formation of vapor bubbles as a result of a neutron flux excursion from the injection of a reactivity increment into the reactor will operate to nullify the reactivity increment within a sufficiently short period of time to prevent unsafe reactor operating conditions from developing. This is obtained by disposing a plurality of fuel elements within a mass of steam forming coolant in the core with the ratio of the volume of steam forming coolant to the volume of fissionable isotopes being within the range yielding a multiplication factor greater than unity and a negative reactivity to core void coefficient at the boiling temperature of the coolant.

Marine Corps CASEVAC: Determining Medical Supply Requirements for Long-Range Casualty Evacuation Aircraft

DTIC Science & Technology

2003-08-01

Force of blades Extreme Moderate Moderate Moderate Temperature Heating, no A/C Heating, no A/C Heating, no A/C Heating, no A/C In-flight refueling Yes...CASEVAC CUBE CASEVAC PRICE 6515013215211 Airway Kit Percutaneous Emergency Adult Sterile Disposable 1.00 EA 0.2000 0.0500 $206.27 6515011676637...UI CASEVAC WEIGHT CASEVAC CUBE CASEVAC PRICE 6515014661488 Crystalloid and Colloid Pump Cartridges And IV Sets for the Power Infuser. Sterile

Expansion of effective wet bulb globe temperature for vapor impermeable protective clothing.

PubMed

Sakoi, Tomonori; Mochida, Tohru; Kurazumi, Yoshihito; Sawada, Shin-Ichi; Horiba, Yosuke; Kuwabara, Kohei

2018-01-01

The wet bulb globe temperature (WBGT) is an effective measure for risk screening to prevent heat dISOrders. However, a heat risk evaluation by WBGT requires adjustments depending on the clothing. In this study, we proposed a new effective WBGT (WBGT eff * ) for general vapor permeable clothing ensembles and vapor impermeable protective clothing that is applicable to occupants engaged in moderate intensity work with a metabolic heat production value of around 174W/m 2 . WBGT eff * enables the conversion of heat stress into the scale experienced by the occupant dressed in the basic clothing ensemble (work clothes) based on the heat balances for a human body. We confirmed that WBGT eff * was effective for expressing the critical thermal environments for the prescriptive zones for occupants wearing vapor impermeable protective clothing. Based on WBGT eff * , we succeeded in clarifying how the weights for natural wet bulb, globe, and air temperatures and the intercept changed depending on clothing properties and the surrounding environmental factors when heat stress is expressed by the weighted sum of natural wet bulb, globe, and air temperatures and the intercept. The weight of environmental temperatures (globe and air temperatures) for WBGT eff * for vapor impermeable protective clothing increased compared with that for general vapor permeable clothing, whereas that of the natural wet bulb temperature decreased. For WBGT eff * in outdoor conditions with a solar load, the weighting ratio of globe temperature increased and that of air temperature decreased with air velocity. Approximation equations of WBGT eff * were proposed for both general vapor permeable clothing ensembles and for vapor impermeable protective clothing. Copyright © 2017 Elsevier Ltd. All rights reserved.

Temperature dynamics of stormwater runoff in Australia and the USA.

PubMed

Hathaway, J M; Winston, R J; Brown, R A; Hunt, W F; McCarthy, D T

2016-07-15

Thermal pollution of surface waters by urban stormwater runoff is an often overlooked by-product of urbanization. Elevated stream temperatures due to an influx of stormwater runoff can be detrimental to stream biota, in particular for cold water systems. However, few studies have examined temperature trends throughout storm events to determine how these thermal inputs are temporally distributed. In this study, six diverse catchments in two continents are evaluated for thermal dynamics. Summary statistics from the data showed larger catchments have lower maximum runoff temperatures, minimum runoff temperatures, and temperature variability. This reinforces the understanding that subsurface drainage infrastructure in urban catchments acts to moderate runoff temperatures. The catchments were also evaluated for the presence of a thermal first flush using two methodologies. Results showed the lack of a first flush under traditional assessment methodologies across all six catchments, supporting the results from a limited number of studies in literature. However, the time to peak temperature was not always coincident with the time to peak flow, highlighting the variability of thermal load over time. When a new first flush methodology was applied, significant differences in temperature were noted with increasing runoff depth for five of the six sites. This study is the first to identify a runoff temperature first flush, and highlights the need to carefully consider the appropriate methodology for such analyses. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of Dopant on Depoling Temperature in Modified BiScO3 - PbTiO3

NASA Technical Reports Server (NTRS)

Kowalski, Benjamin; Sehirlioglu, Alp

2014-01-01

In recent years there has been a renewed interest for high temperature piezoelectrics for both terrestrial and aerospace applications. These applications are limited in part by the operating temperature, which is usually taken as one half of the Curie temperature (Tc), and is 200C for one of the most widely used commercial piezoelectrics, Pb(Zr,Ti)O3 (PZT). In an effort to increase Tc, subsequent research into high temperature Bi(BB)O3 PbTiO3 piezoelectrics led to the discovery of the morphotropic phase boundary (MPB) in the high-Tc BiScO3 PbTiO3 (BS-PT) system with a Tc of 460C and a d33 of 460 pmV. The Tc marks the ferroelectric to paraelectric phase transformation and while, in general, a phase transformation leads to thermal depoling in piezoelectrics with low or moderate Tcs, for high Tc piezoelectrics thermally assisted dipole rotation can lead to randomization of domains at temperatures below Tc. It becomes necessary to determine the depoling temperature (Td) which dictates the actual working temperature range. By doping for Sc and Ti the Td can be shifted while maintaining similar electromechanical properties as a function of temperature. The effect of this B-site doping on depoling temperature has been explored through the characterization of microstructure and weakhigh field measurements.

Mechanical Behavior of AZ31B Mg Alloy Sheets under Monotonic and Cyclic Loadings at Room and Moderately Elevated Temperatures

PubMed Central

Nguyen, Ngoc-Trung; Seo, Oh Suk; Lee, Chung An; Lee, Myoung-Gyu; Kim, Ji-hoon; Kim, Heon Young

2014-01-01

Large-strain monotonic and cyclic loading tests of AZ31B magnesium alloy sheets were performed with a newly developed testing system, at different temperatures, ranging from room temperature to 250 °C. Behaviors showing significant twinning during initial in-plane compression and untwinning in subsequent tension at and slightly above room temperature were recorded. Strong yielding asymmetry and nonlinear hardening behavior were also revealed. Considerable Bauschinger effects, transient behavior, and variable permanent softening responses were observed near room temperature, but these were reduced and almost disappeared as the temperature increased. Different stress–strain responses were inherent to the activation of twinning at lower temperatures and non-basal slip systems at elevated temperatures. A critical temperature was identified to account for the transition between the twinning-dominant and slip-dominant deformation mechanisms. Accordingly, below the transition point, stress–strain curves of cyclic loading tests exhibited concave-up shapes for compression or compression following tension, and an unusual S-shape for tension following compression. This unusual shape disappeared when the temperature was above the transition point. Shrinkage of the elastic range and variation in Young’s modulus due to plastic strain deformation during stress reversals were also observed. The texture-induced anisotropy of both the elastic and plastic behaviors was characterized experimentally. PMID:28788514

Vegetation greenness trend (2000 to 2009) and the climate controls in the Qinghai-Tibetan Plateau

USGS Publications Warehouse

Zhang, Li; Guo, Huadong; Ji, Lei; Lei, Liping; Wang, Cuizhen; Yan, Dongmei; Li, Bin; Li, Jing

2013-01-01

The Qinghai-Tibetan Plateau has been experiencing a distinct warming trend, and climate warming has a direct and quick impact on the alpine grassland ecosystem. We detected the greenness trend of the grasslands in the plateau using Moderate Resolution Imaging Spectroradiometer data from 2000 to 2009. Weather station data were used to explore the climatic drivers for vegetation greenness variations. The results demonstrated that the region-wide averaged normalized difference vegetation index (NDVI) increased at a rate of 0.036  yr−1. Approximately 20% of the vegetation areas, which were primarily located in the northeastern plateau, exhibited significant NDVI increase trend (p-value <0.05). Only 4% of the vegetated area showed significant decrease trends, which were mostly in the central and southwestern plateau. A strong positive relationship between NDVI and precipitation, especially in the northeastern plateau, suggested that precipitation was a favorable factor for the grassland NDVI. Negative correlations between NDVI and temperature, especially in the southern plateau, indicated that higher temperature adversely affected the grassland growth. Although a warming climate was expected to be beneficial to the vegetation growth in cold regions, the grasslands in the central and southwestern plateau showed a decrease in trends influenced by increased temperature coupled with decreased precipitation.

Mechanism and Effect of Temperature on Variations in Antibiotic Resistance Genes during Anaerobic Digestion of Dairy Manure

PubMed Central

Sun, Wei; Qian, Xun; Gu, Jie; Wang, Xiao-Juan; Duan, Man-Li

2016-01-01

Animal manure comprises an important reservoir for antibiotic resistance genes (ARGs), but the variation in ARGs during anaerobic digestion at various temperatures and its underlying mechanism remain unclear. Thus, we performed anaerobic digestion using dairy manure at three temperature levels (moderate: 20 °C, mesophilic: 35 °C, and thermophilic: 55 °C), to analyze the dynamics of ARGs and bacterial communities by quantitative PCR and 16S rRNA gene sequencing. We found that 8/10 detected ARGs declined and 5/10 decreased more than 1.0 log during thermophilic digestion, whereas only four and five ARGs decreased during moderate and mesophilic digestion, respectively. The changes in ARGs and bacterial communities were similar under the moderate and mesophilic treatments, but distinct from those in the thermophilic system. Potential pathogens such as Bacteroidetes, Proteobacteria, and Corynebacterium were removed by thermophilic digestion but not by moderate and mesophilic digestion. The bacterial community succession was the dominant mechanism that influenced the variation in ARGs and integrons during anaerobic digestion. Thermophilic digestion decreased the amount of mesophilic bacteria (Bacteroidetes and Proteobacteria) carrying ARGs. Anaerobic digestion generally decreased the abundance of integrons by eliminating the aerobic hosts of integrons (Actinomycetales and Bacilli). Thermophilic anaerobic digestion is recommended for the treatment and reuse of animal manure. PMID:27444518

Outdoor temperature, precipitation, and wind speed affect physical activity levels in children: a longitudinal cohort study

PubMed Central

Edwards, Nicholas M.; Myer, Gregory D.; Kalkwarf, Heidi J.; Woo, Jessica G.; Khoury, Philip R.; Hewett, Timothy E.; Daniels, Stephen R.

2015-01-01

Objective Evaluate effects of local weather conditions on physical activity in early childhood. Methods Longitudinal prospective cohort study of 372 children, 3 years old at enrollment, drawn from a major US metropolitan community. Accelerometer-measured (RT3) physical activity was collected every 4 months over 5 years and matched with daily weather measures: day length, heating/cooling degrees (degrees mean temperature < 65°F or ≥ 65°F, respectively), wind, and precipitation. Mixed regression analyses, adjusted for repeated measures, were used to test the relationship between weather and physical activity. Results Precipitation and wind speed were negatively associated with total physical activity and moderate-vigorous physical activity (P<0.0001). Heating and cooling degrees were negatively associated with total physical activity and moderate-vigorous physical activity and positively associated with inactivity (all P<0.0001), independent of age, sex, race, BMI, day length, wind, and precipitation. For every 10 additional heating degrees there was a five-minute daily reduction in moderate-vigorous physical activity. For every additional 10 cooling degrees there was a 17-minute reduction in moderate-vigorous physical activity. Conclusions Inclement weather (higher/lower temperature, greater wind speed, more rain/snow) is associated with less physical activity in young children. These deleterious effects should be considered when planning physical activity research, interventions, and policies. PMID:25423667

Tamper resistant magnetic stripes

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

Naylor, R.B.; Sharp, D.J.

1999-11-09

This invention relates to a magnetic stripe comprising a medium in which magnetized particles are suspended and in which the encoded information is recorded by actual physical rotation or alignment of the previously magnetized particles within the flux reversals of the stripe which are 180{degree} opposed in their magnetic polarity. The magnetized particles are suspended in a medium which is solid, or physically rigid, at ambient temperatures but which at moderately elevated temperatures, such as 40 C, is thinable to a viscosity permissive of rotation of the particles therein under applications of moderate external magnetic field strengths within acceptable timemore » limits.« less

Phase 0 study for a geothermal superheated water proof of concept facility

NASA Technical Reports Server (NTRS)

Douglass, R. H.; Pearson, R. O.

1974-01-01

A Phase 0 study for the selection of a representative liquid-dominated geothermal resource of moderate salinity and temperature is discussed. Selection and conceptual design of a nominal 10-MWe energy conversion system, and implementation planning for Phase 1: subsystem (component, experiments) and Phase 2: final design, construction, and operation of experimental research facilities are reported. The objective of the overall program is to demonstrate the technical and economic viability of utilizing moderate temperature and salinity liquid-dominated resources with acceptable environmental impact, and thus encourage commercial scale development of geothermal electrical power generation.

Tamper resistant magnetic stripes

DOEpatents

Naylor, Richard Brian; Sharp, Donald J.

1999-01-01

This invention relates to a magnetic stripe comprising a medium in which magnetized particles are suspended and in which the encoded information is recorded by actual physical rotation or alignment of the previously magnetized particles within the flux reversals of the stripe which are 180.degree. opposed in their magnetic polarity. The magnetized particles are suspended in a medium which is solid, or physically rigid, at ambient temperatures but which at moderately elevated temperatures, such as 40.degree. C., is thinable to a viscosity permissive of rotation of the particles therein under applications of moderate external magnetic field strengths within acceptable time limits.

Atmospheric Amines and Ammonia Measured with a Chemical Ionization Mass Spectrometer (CIMS)

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

You, Y.; Kanawade, V. P.; de Gouw, J. A.

We report ambient measurements of amines and ammonia with a fast response chemical ionization mass spectrometer (CIMS) in a Southeastern U.S. forest in Alabama and a moderately polluted Midwestern site during the summer. In the Alabama forest, mostly C3-amines (from pptv to tens of pptv) and ammonia (up to 2 ppbv) were detected on a daily basis. C3-amines and ammonia showed similar diurnal trends and temperature and wind direction dependences, and were not associated with transported CO and SO2 plumes. Consistent with temperature dependences, amine and ammonia in the gas and aerosol phases showed opposite diurnal trends, indicating gas-to-particle partitioningmore » of amines and ammonia. Temperature dependences also imply reversible processes of amines and ammonia evaporation from soil surfaces in daytime and deposition of amines and ammonia to soil surfaces at nighttime. Various amines (C1-C6) at the pptv level were observed in the transported biomass burning plumes, showing that biomass burning can be a substantial source of amines in the Southeast U.S. At the moderately polluted Kent site, higher concentrations of amines (C1-C6, from pptv to tens of pptv) and ammonia (up to 6 ppbv) were detected. Diurnal variations of C1- to C3-amines and ammonia were correlated with the ambient temperature. C4- to C6-amines showed abrupt increases during the nighttime, suggesting that they were emitted from local sources. These abundant amines and ammonia may in part explain the frequent new particle formation events reported from Kent. Lower amine concentrations at the rural forested site highlight the importance of constraining anthropogenic sources of amines.« less

Temperature, hydric environment, and prior pathogen exposure alter the experimental severity of chytridiomycosis in boreal toads

USGS Publications Warehouse

Murphy, Peter J.; St-Hilaire, Sophie; Corn, Paul Stephen

2011-01-01

Prevalence of the pathogen Batrachochytrium dendrobatidis (Bd), implicated in amphibian population declines worldwide, is associated with habitat moisture and temperature, but few studies have varied these factors and measured the response to infection in amphibian hosts. We evaluated how varying humidity, contact with water, and temperature affected the manifestation of chytridiomycosis in boreal toads Anaxyrus (Bufo) boreas boreas and how prior exposure to Bd affects the likelihood of survival after re-exposure, such as may occur seasonally in long-lived species. Humidity did not affect survival or the degree of Bd infection, but a longer time in contact with water increased the likelihood of mortality. After exposure to ~106 Bd zoospores, all toads in continuous contact with water died within 30 d. Moreover, Bd-exposed toads that were disease-free after 64 d under dry conditions, developed lethal chytridiomycosis within 70 d of transfer to wet conditions. Toads in unheated aquaria (mean = 15°C) survived less than 48 d, while those in moderately heated aquaria (mean = 18°C) survived 115 d post-exposure and exhibited behavioral fever, selecting warmer sites across a temperature gradient. We also found benefits of prior Bd infection: previously exposed toads survived 3 times longer than Bd-naïve toads after re-exposure to 106 zoospores (89 vs. 30 d), but only when dry microenvironments were available. This study illustrates how the outcome of Bd infection in boreal toads is environmentally dependent: when continuously wet, high reinfection rates may overwhelm defenses, but periodic drying, moderate warming, and previous infection may allow infected toads to extend their survival.

Adaptations to Submarine Hydrothermal Environments Exemplified by the Genome of Nautilia profundicola

PubMed Central

Campbell, Barbara J.; Smith, Julie L.; Hanson, Thomas E.; Klotz, Martin G.; Stein, Lisa Y.; Lee, Charles K.; Wu, Dongying; Robinson, Jeffrey M.; Khouri, Hoda M.; Eisen, Jonathan A.; Cary, S. Craig

2009-01-01

Submarine hydrothermal vents are model systems for the Archaean Earth environment, and some sites maintain conditions that may have favored the formation and evolution of cellular life. Vents are typified by rapid fluctuations in temperature and redox potential that impose a strong selective pressure on resident microbial communities. Nautilia profundicola strain Am-H is a moderately thermophilic, deeply-branching Epsilonproteobacterium found free-living at hydrothermal vents and is a member of the microbial mass on the dorsal surface of vent polychaete, Alvinella pompejana. Analysis of the 1.7-Mbp genome of N. profundicola uncovered adaptations to the vent environment—some unique and some shared with other Epsilonproteobacterial genomes. The major findings included: (1) a diverse suite of hydrogenases coupled to a relatively simple electron transport chain, (2) numerous stress response systems, (3) a novel predicted nitrate assimilation pathway with hydroxylamine as a key intermediate, and (4) a gene (rgy) encoding the hallmark protein for hyperthermophilic growth, reverse gyrase. Additional experiments indicated that expression of rgy in strain Am-H was induced over 100-fold with a 20°C increase above the optimal growth temperature of this bacterium and that closely related rgy genes are present and expressed in bacterial communities residing in geographically distinct thermophilic environments. N. profundicola, therefore, is a model Epsilonproteobacterium that contains all the genes necessary for life in the extreme conditions widely believed to reflect those in the Archaean biosphere—anaerobic, sulfur, H2- and CO2-rich, with fluctuating redox potentials and temperatures. In addition, reverse gyrase appears to be an important and common adaptation for mesophiles and moderate thermophiles that inhabit ecological niches characterized by rapid and frequent temperature fluctuations and, as such, can no longer be considered a unique feature of hyperthermophiles. PMID:19197347

Projections and downscaling of 21st century temperatures, precipitation, radiative fluxes and winds for the southwestern US, with focus on the Lake Tahoe basin

USGS Publications Warehouse

Dettinger, Michael D.

2013-01-01

Recent projections of global climate changes in response to increasing greenhouse-gas concentrations in the atmosphere include warming in the Southwestern US and, especially, in the vicinity of Lake Tahoe of from about +3°C to +6°C by end of century and changes in precipitation on the order of 5-10 % increases or (more commonly) decreases, depending on the climate model considered. Along with these basic changes, other climate variables like solar insolation, downwelling (longwave) radiant heat, and winds may change. Together these climate changes may result in changes in the hydrology of the Tahoe basin and potential changes in lake overturning and ecological regimes. Current climate projections, however, are generally spatially too coarse (with grid cells separated by 1 to 2° latitude and longitude) for direct use in assessments of the vulnerabilities of the much smaller Tahoe basin. Thus, daily temperatures, precipitation, winds, and downward radiation fluxes from selected global projections have been downscaled by a statistical method called the constructed-analogues method onto 10 to 12 km grids over the Southwest and especially over Lake Tahoe. Precipitation, solar insolation and winds over the Tahoe basin change only moderately (and with indeterminate signs) in the downscaled projections, whereas temperatures and downward longwave fluxes increase along with imposed increases in global greenhouse-gas concentrations.

Effect of sodium, potassium, magnesium, calcium, and chlorine on the high temperature corrosion of IN-100, U-700, IN-792, and Mar M-509. [coal-derived liquid fuel combustion in turbines

NASA Technical Reports Server (NTRS)

Lowell, C. E.; Sidik, S. M.; Deadmore, D. L.

1980-01-01

The effects of potential impurities such as Na, K, Mg, Ca, and Cl, in coal-derived liquid fuels on accelerated corrosion of IN-100, U-700, IN-792, and Mar M-509 were investigated using a Mach 0.3 burner rig for times to 200 hours in one hour cycles. These impurities were injected in combination as aqueous solutions into the combustor. Other variables were time, temperature, and fuel-to-air ratio. The experimental matrix was a central composite fractional fractorial design divided into blocks to allow modification of the design as data was gathered. The extent of corrosion was determined by metal consumption. The time exponent was near 1.0 for the least corrosion resistant alloys, U-700 and IN-100; near 0.8 for the moderately resistant IN-792; and close to Mar M-509, the most corrosion resistant alloy. As anticipated, corrosion rapidly increased with increasing temperature as well as Na and K concentrations, while corrosion decreased somewhat as the Ca concentration increased for all alloys. Mg was beneficial for the Ni-base alloys but had little effect on the Co-base alloy. Surprisingly, the effect of increasing Cl was to decrease the corrosion of all alloys. Little interaction among the dopants was noted.

Impacts of climate change on heat-related mortality risk across the Middle East and North Africa (MENA)

NASA Astrophysics Data System (ADS)

Moradkhani, H.; Ahmadalipour, A.

2017-12-01

It has been reported that even if the global mean temperature increase is limited to 2°C, warming over land will be far beyond that in many regions. Global climate change will increase the frequency and intensity of heatwaves and extreme high temperatures, which will in turn have severe impacts on human life. In this study, the mortality risk caused by excessive heat stress is investigated. Daily maximum air temperature and relative humidity are acquired from 17 CMIP5 Regional Climate Models (RCMs) developed by CORDEX at 0.44 degree spatial resolution. Then, the daily wet-bulb temperature is calculated and a recently developed health risk model is implemented to quantify the mortality risk. The study is applied over the latitudes 6.6°S-42°N and longitudes 20°W-60°E covering parts of 70 countries and accommodating over 600 million inhabitants. The analysis is performed for the historical period of 1951-2005 as well as two future scenarios of RCP4.5 (moderate) and RCP8.5 (business as usual) during 2006-2100. Results indicate about 5 to 30 times higher mortality risk in distant future compared to the historical period. The most aggravation of mortality risk over land is found at the southwestern regions of MENA, due to substantial increase in frequency and intensity of extreme temperatures. Mortality risk is found to be much higher over open waters and coastal regions due to abundant humidity, especially in the coastal regions of the Red sea and Persian Gulf.

The surprising recovery of red spruce growth shows links to decreased acid deposition and elevated temperature.

PubMed

Kosiba, Alexandra M; Schaberg, Paul G; Rayback, Shelly A; Hawley, Gary J

2018-10-01

Following growth declines and increased mortality linked to acid deposition-induced calcium depletion, red spruce (Picea rubens Sarg.) in the northeastern United States are experiencing a recovery. We found that more than 75% of red spruce trees and 90% of the plots examined in this study exhibited increasing growth since 2001. To understand this change, we assessed the relationship between red spruce radial growth and factors that may influence growth: tree age and diameter, stand dynamics, plot characteristics (elevation, slope, aspect, geographical position), and a suite of environmental variables (temperature, precipitation, climate and precipitation indices (degree days, SPEI [standardized precipitation evapotranspiration index], and acid deposition [SO 4 2- , NO 3 - , pH of rainfall, cation:anion ratio of rainfall]) for 52 plots (658 trees) from five states (spanning 2.5°N × 5°W). Examining the growth relationships from 1925 to 2012, we found that while there was variability in response to climate and acid deposition (limited to 1980-2012) by elevation and location, plot and tree factors did not adequately explain growth. Higher temperatures outside the traditional growing season (e.g., fall, winter, and spring) were related to increased growth. Nitrogen deposition (1980-2012) was associated with lower growth, but the strength of this relationship has lessened over time. Overall, we predict sustained favorable conditions for red spruce in the near term as acid deposition continues to decline and non-traditional growing season (fall through spring) temperatures moderate, provided that overall temperatures and precipitation remain adequate for growth. Copyright © 2018 Elsevier B.V. All rights reserved.

Influence of age and selected environmental factors on reproductive performance of canvasbacks

USGS Publications Warehouse

Serie, Jerome R.; Trauger, David L.; Austin, Jane E.

1992-01-01

Age, productivity, and other factors affecting breeding performance of canvasbacks (Aythya valisineria) are poorly understood. Consequently, we tested whether reproductive performance of female canvasbacks varied with age and selected environmental factors in southwestern Manitoba from 1974 to 1980. Neither clutch size, nest parasitism, nest success, nor the number of ducklings/brood varied with age. Return rates, nest initiation dates, renesting, and hen success were age-related. Return rates averaged 21% for second-year (SY) and 69% for after-second-year (ASY) females (58% for third-year and 79% for after-third-year females). Additionally, water conditions and spring temperatures influenced chronology of arrival, timing of nesting, and reproductive success. Nest initiation by birds of all ages was affected by minimum April temperatures. Clutch size was higher in nests initiated earlier. Interspecific nest parasitism did not affect clutch size, nest success, hen success, or hatching success. Nest success was lower in dry years (17%) than in moderately wet (54%) or wet (60%) years. Nests per female were highest during wet years. No nests of SY females were found in dry years. In years of moderate to good wetland conditions, females of all ages nested. Predation was the primary factor influencing nest success. Hen success averaged 58% over all years. The number of ducklings surviving 20 days averaged 4.7/brood. Because SY females have lower return rates and hen success than ASY females, especially during drier years, management to increase canvasback populations might best be directed to increasing first year recruitment (no. of females returning to breed) and to increasing overall breeding success by reducing predation and enhancing local habitat conditions during nesting.

Interactions with successional stage and nutrient status determines the life-form-specific effects of increased soil temperature on boreal forest floor vegetation.

PubMed

Hedwall, Per-Ola; Skoglund, Jerry; Linder, Sune

2015-02-01

The boreal forest is one of the largest terrestrial biomes and plays a key role for the global carbon balance and climate. The forest floor vegetation has a strong influence on the carbon and nitrogen cycles of the forests and is sensitive to changes in temperature conditions and nutrient availability. Additionally, the effects of climate warming on forest floor vegetation have been suggested to be moderated by the tree layer. Data on the effects of soil warming on forest floor vegetation from the boreal forest are, however, very scarce. We studied the effects on the forest floor vegetation in a long-term (18 years) soil warming and fertilization experiment in a Norway spruce stand in northern Sweden. During the first 9 years, warming favored early successional species such as grasses and forbs at the expense of dwarf shrubs and bryophytes in unfertilized stands, while the effects were smaller after fertilization. Hence, warming led to significant changes in species composition and an increase in species richness in the open canopy nutrient limited forest. After another 9 years of warming and increasing tree canopy closure, most of the initial effects had ceased, indicating an interaction between forest succession and warming. The only remaining effect of warming was on the abundance of bryophytes, which contrary to the initial phase was strongly favored by warming. We propose that the suggested moderating effects of the tree layer are specific to plant life-form and conclude that the successional phase of the forest may have a considerable impact on the effects of climate change on forest floor vegetation and its feedback effects on the carbon and nitrogen cycles, and thus on the climate.

Interactions with successional stage and nutrient status determines the life-form-specific effects of increased soil temperature on boreal forest floor vegetation

PubMed Central

Hedwall, Per-Ola; Skoglund, Jerry; Linder, Sune

2015-01-01

The boreal forest is one of the largest terrestrial biomes and plays a key role for the global carbon balance and climate. The forest floor vegetation has a strong influence on the carbon and nitrogen cycles of the forests and is sensitive to changes in temperature conditions and nutrient availability. Additionally, the effects of climate warming on forest floor vegetation have been suggested to be moderated by the tree layer. Data on the effects of soil warming on forest floor vegetation from the boreal forest are, however, very scarce. We studied the effects on the forest floor vegetation in a long-term (18 years) soil warming and fertilization experiment in a Norway spruce stand in northern Sweden. During the first 9 years, warming favored early successional species such as grasses and forbs at the expense of dwarf shrubs and bryophytes in unfertilized stands, while the effects were smaller after fertilization. Hence, warming led to significant changes in species composition and an increase in species richness in the open canopy nutrient limited forest. After another 9 years of warming and increasing tree canopy closure, most of the initial effects had ceased, indicating an interaction between forest succession and warming. The only remaining effect of warming was on the abundance of bryophytes, which contrary to the initial phase was strongly favored by warming. We propose that the suggested moderating effects of the tree layer are specific to plant life-form and conclude that the successional phase of the forest may have a considerable impact on the effects of climate change on forest floor vegetation and its feedback effects on the carbon and nitrogen cycles, and thus on the climate. PMID:25750720

Photosynthetic capacity and leaf nitrogen decline along a controlled climate gradient in provenances of two widely distributed Eucalyptus species.

PubMed

Crous, Kristine Y; Drake, John E; Aspinwall, Michael J; Sharwood, Robert E; Tjoelker, Mark G; Ghannoum, Oula

2018-05-27

Climate is an important factor limiting tree distributions and adaptation to different thermal environments may influence how tree populations respond to climate warming. Given the current rate of warming, it has been hypothesized that tree populations in warmer, more thermally stable climates may have limited capacity to respond physiologically to warming compared to populations from cooler, more seasonal climates. We determined in a controlled environment how several provenances of widely distributed Eucalyptus tereticornis and E. grandis adjusted their photosynthetic capacity to +3.5°C warming along their native distribution range (~16-38°S) and whether climate of seed origin of the provenances influenced their response to different growth temperatures. We also tested how temperature optima (T opt ) of photosynthesis and J max responded to higher growth temperatures. Our results showed increased photosynthesis rates at a standardized temperature with warming in temperate provenances, while rates in tropical provenances were reduced by about 40% compared to their temperate counterparts. Temperature optima of photosynthesis increased as provenances were exposed to warmer growth temperatures. Both species had ~30% reduced photosynthetic capacity in tropical and subtropical provenances related to reduced leaf nitrogen and leaf Rubisco content compared to temperate provenances. Tropical provenances operated closer to their thermal optimum and came within 3% of the T opt of J max during the daily temperature maxima. Hence, further warming may negatively affect C uptake and tree growth in warmer climates, whereas eucalypts in cooler climates may benefit from moderate warming. © 2018 John Wiley & Sons Ltd.

Heavy fermion behavior explained by bosons

NASA Technical Reports Server (NTRS)

Kallio, A.; Poykko, S.; Apaja, V.

1995-01-01

Conventional heavy fermion (HF) theories require existence of massive fermions. We show that heavy fermion phenomena can also be simply explained by existence of bosons with moderate mass but temperature dependent concentration below the formation temperature T(sub B), which in turn is close to room temperature. The bosons B(++) are proposed to be in chemical equilibrium with a system of holes h(+): B(++) = h(+) + h(+). This equilibrium is governed by a boson breaking function f(T), which determines the decreasing boson density and the increasing fermion density with increasing temperature. Since HF-compounds are hybridized from minimum two elements, we assume in addition existence of another fermion component h(sub s)(+) with temperature independent density. This spectator component is thought to be the main agent in binding the bosons in analogy with electronic or muonic molecules. Using a linear boson breaking function we can explain temperature dependence of the giant linear specific heat coefficient gamma(T) coming essentially from bosons. The maxima in resistivity, Hall coefficient, and susceptibility are explained by boson localization effects due to the Wigner crystallization. The antiferromagnetic transitions in turn are explained by similar localization of the pairing fermion system when their density n(sub h)(T(sub FL)) becomes lower than n(sub WC), the critical density of Wigner crystallization. The model applies irrespective whether a compound is superconducting or not. The same model explains the occurrence of low temperature antiferromagnetism also in high-T(sub c) superconductors. The double transition in UPt3 is proposed to be due to the transition of the pairing fermion liquid from spin polarized to unpolarized state.

Heat Capacity of Hydrous Silicate Melts

NASA Astrophysics Data System (ADS)

Robert, G.; Whittington, A. G.; Stechern, A.; Behrens, H.

2015-12-01

We determined the heat capacities of four series of glasses and liquids of basaltic and basaltic andesite compositions including two natural remelts from Fuego volcano, Guatemala, and two Fe-free analogs. The samples are low-alkali, Ca- and Mg-rich aluminosilicates with non-bridging oxygen to tetrahedrally-coordinated cation ratios (NBO/T) ranging between 0.33 and 0.67. Differential scanning calorimetry measurements were performed at atmospheric pressure between room temperature and ≈100 K above the glass transition for hydrous samples and up to ≈1800 K for dry samples. The water contents investigated range up to 5.34 wt.% (16.4 mol%). Water does not measurably affect the heat capacity of glasses (T

Phase diagram, correlation gap, and critical properties of the coulomb glass.

PubMed

Goethe, Martin; Palassini, Matteo

2009-07-24

We investigate the lattice Coulomb glass model in three dimensions via Monte Carlo simulations. No evidence for an equilibrium glass phase is found down to very low temperatures, although the correlation length increases rapidly near T = 0. A charge-ordered phase exists at low disorder. The transition to this phase is consistent with the random field Ising universality class, which shows that the interaction is effectively screened at moderate temperature. For large disorder, the single-particle density of states near the Coulomb gap satisfies the scaling relation g(epsilon, T) = T;{delta}f(|epsilon|/T) with delta = 2.01 +/- 0.05 in agreement with the prediction of Efros and Shklovskii. For decreasing disorder, a crossover to a larger effective exponent occurs due to the proximity of the charge-ordered phase.

Phase diagram, correlation gap, and critical properties of the Coulomb glass

NASA Astrophysics Data System (ADS)

Palassini, Matteo; Goethe, Martin

2009-03-01

We investigate the lattice Coulomb glass model in three dimensions via extensive Monte Carlo simulations. 1. No evidence for an equilibrium glass phase is found down to very low temperatures, contrary to mean-field predictions, although the correlation length increases rapidly near T=0. 2. The single-particle density of states near the Coulomb gap satisfies the scaling law g(e,T)=T^λf(e/T) with λ 2.2. 3. A charge-ordered phase exists at low disorder. The phase transition from the fluid to the charge ordered phase is consistent with the Random Field Ising universality class, which shows that the interaction is effectively screened at moderate temperature. Results from nonequilibrium simulations will also be briefly discussed. Reference: M.Goethe and M.Palassini, arXiv:0810.1047

Asylum applications respond to temperature fluctuations.

PubMed

Missirian, Anouch; Schlenker, Wolfram

2017-12-22

International negotiations on climate change, along with recent upsurges in migration across the Mediterranean Sea, have highlighted the need to better understand the possible effects of climate change on human migration-in particular, across national borders. Here we examine how, in the recent past (2000-2014), weather variations in 103 source countries translated into asylum applications to the European Union, which averaged 351,000 per year in our sample. We find that temperatures that deviated from the moderate optimum (~20°C) increased asylum applications in a nonlinear fashion, which implies an accelerated increase under continued future warming. Holding everything else constant, asylum applications by the end of the century are predicted to increase, on average, by 28% (98,000 additional asylum applications per year) under representative concentration pathway (RCP) scenario 4.5 and by 188% (660,000 additional applications per year) under RCP 8.5 for the 21 climate models in the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP). Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Component effects on crystallization of RE-containing aluminoborosilicate glass

NASA Astrophysics Data System (ADS)

Mohd Fadzil, Syazwani; Hrma, Pavel; Schweiger, Michael J.; Riley, Brian J.

2016-09-01

Lanthanide-aluminoborosilicate (LABS) glass is one option for immobilizing rare earth (RE) oxide fission products generated during reprocessing of pyroprocessed fuel. This glass system can accommodate a high loading of RE oxides and has excellent chemical durability. The present study describes efforts to model equilibrium crystallinity as a function of glass composition and temperature as well as liquidus temperature (TL) as a function of glass composition. The experimental method for determining TL was ASTM C1720-11. Typically, three crystalline phases were formed in each glass: Ce-borosilicate (Ce3BSi2O10), mullite (Al10Si2O19), and corundum (Al2O3). Cerianite (CeO2) was a common minor crystalline phase and Nd-silicate (Nd2Si2O7) occurred in some of the glasses. In the composition region studied, TL decreased as SiO2 and B2O3 fractions increased and strongly increased with increasing fractions of RE oxides; Al2O3 had a moderate effect on the TL but, as expected, it strongly affected the precipitation of Al-containing crystals.

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

Mohd Fadzil, Syazwani; Hrma, Pavel; Schweiger, Michael J.

Lanthanide-aluminoborosilicate (LABS) glass is one option for immobilizing rare earth (RE) oxide fission products generated during reprocessing of pyroprocessed fuel. This glass system can accommodate a high loading of RE oxides and has excellent chemical durability. The present study describes efforts to model equilibrium crystallinity as a function of glass composition and temperature as well as liquidus temperature (TL) as a function of glass composition. The experimental method for determining TL was ASTM C1720-11. Typically, three crystalline phases were formed in each glass: Ce-borosilicate (Ce 3BSi 2O 10), mullite (Al 10Si 2O 19), and corundum (Al 2O 3). Cerianite (CeOmore » 2) was a common minor crystalline phase and Nd-silicate (Nd 2Si 2O 7) occurred in some of the glasses. In the composition region studied, TL decreased as SiO 2 and B 2O 3 fractions increased and strongly increased with increasing fractions of RE oxides; Al 2O 3 had a moderate effect on the TL but, as expected, it strongly affected the precipitation of Alcontaining crystals.« less

Thermal conductance of and heat generation in tire-pavement interface and effect on aircraft braking

NASA Technical Reports Server (NTRS)

Miller, C. D.

1976-01-01

A finite-difference analysis was performed on temperature records obtained from a free rolling automotive tire and from pavement surface. A high thermal contact conductance between tire and asphalt was found on a statistical basis. Average slip due to squirming between tire and asphalt was about 1.5 mm. Consequent friction heat was estimated as 64 percent of total power absorbed by bias-ply, belted tire. Extrapolation of results to aircraft tire indicates potential braking improvement by even moderate increase of heat absorbing capacity of runway surface.

Evaluation of High Temperature Properties and Microstructural Characterization of Resistance Spot Welded Steel Lap Shear Joints

NASA Astrophysics Data System (ADS)

Gupta, R. K.; Anil Kumar, V.; Panicker, Paul G.

2016-02-01

Joining of thin sheets (0.5 mm) of stainless steel 304 and 17-4PH through resistance spot welding is highly challenging especially when joint is used for high temperature applications. Various combinations of stainless steel sheets of thickness 0.5 mm are spot welded and tested at room temperature as well as at high temperatures (800 K, 1,000 K, 1,200 K). Parent metal as well as spot welded joints are tested and characterized. It is observed that joint strength of 17-4PH steel is highest and then dissimilar steel joint of 17-4PH with SS-304 is moderate and of SS-304 is lowest at all the temperatures. Joint strength of 17-4PH steel is found to be >80% of parent metal properties up to 1,000 K then drastic reduction in strength is noted at 1,200 K. Gradual reduction in strength of SS-304 joint with increase in temperature from 800 to 1,200 K is noted. At 1,200 K, joint strength of all combinations of joints is found to be nearly same. Microstructural evaluation of weld nugget after testing at different temperatures shows presence of tempered martensite in 17-4PH containing welds and homogenized structure in stainless steel 304 weld.

Sensitivity of Clay Suspension Rheological Properties to pH, Temperature, Salinity, and Smectite-Quartz Ratio

NASA Astrophysics Data System (ADS)

Kameda, Jun; Morisaki, Tomonori

2017-10-01

Understanding the rheological properties of clay suspensions is critical to assessing the behavior of sediment gravity flows such as debris flow or turbidity current. We conducted rheological measurements of composite smectite-quartz suspensions at a temperature of 7°C and a salt concentration of 0.6 M. This is representative of smectite-bearing sediments under conditions on the seafloor. The flow curves obtained were fitted by the Bingham fluid model, from which we determined the Bingham yield stress and dynamic viscosity of each suspension. At a constant smectite-quartz mixing ratio, the yield stress and the dynamic viscosity tend to increase as the solid/water ratio of the suspension is increased. In the case of a constant solid/water ratio, these values increase with increasing smectite content in the smectite-quartz mixture. Additional experiments exploring differing physicochemical conditions (pH 1.0-9.0; temperature 2-30°C; and electrolyte (NaCl) concentration 0.2-0.6 M) revealed that the influence of temperature is negligible, while pH moderately affects the rheology of the suspension. More significantly, the electrolyte concentration greatly affects the flow behavior. These variations can be explained by direct and/or indirect (double-layer) interactions between smectite-smectite particles as well as between smectite-quartz particles in the suspension. Although smectite is known as a frictionally weak material, our experimental results suggest that its occurrence can reduce the likelihood that slope failure initiates. Furthermore, smectite can effectively suppress the spreading distance once the slope has failed.

Is greater temperature change within a day associated with increased emergency admissions for schizophrenia?

PubMed

Zhao, Desheng; Zhang, Xulai; Xie, Mingyu; Cheng, Jian; Zhang, Heng; Wang, Shusi; Li, Kesheng; Yang, Huihui; Wen, Liying; Wang, Xu; Su, Hong

2016-10-01

Diurnal temperature range (DTR), as an important index of climate change, has been increasingly used to evaluate the impacts of temperature variability on human health. However, little is known about the effects of DTR on schizophrenia. The present study aims to examine the relationship between DTR and schizophrenia admissions, and further, to explore whether the association varied by individual characteristics and study periods. A Poisson generalized linear regression combined with distributed lag non-linear model (DLNM) was applied to analyze daily DTR and schizophrenia data from Hefei, China during 2005 to 2014, after adjusting for long-term and seasonal trends, mean temperature, relative humidity and other confounding factors. An acute adverse effect of extremely high DTR on schizophrenia was observed, with a 2.7% (95% CI: 1.007-1.047) increase of daily schizophrenia admissions after exposure to extremely high DTR (95th percentile vs. 50th percentile). The risk for schizophrenia onset due to large DTR exposure increased from the first five years (2005-2009) to the second five years (2010-2014). Additionally, the patient aged 15-29 and 50-64years, male patients, patients born in spring/autumn, and married patients appeared to be more vulnerable to DTR effect. However, there was no significant association between moderately high DTR (75th percentile) and schizophrenia. This study suggests that extremely high DTR is a potential trigger for schizophrenia admissions in Hefei, China. Our findings may provide valuable information to decisions-makers and guidance to health practitioners. Copyright © 2016 Elsevier B.V. All rights reserved.

Interaction of curcumin with 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine liposomes: Intercalation of rhamnolipids enhances membrane fluidity, permeability and stability of drug molecule.

PubMed

Moussa, Zeinab; Chebl, Mazhar; Patra, Digambara

2017-01-01

Stability of curcumin in neutral and alkaline buffer conditions has been a serious concern for its medicinal applications. We demonstrate that the stability of curucmin can be improved in 1,2-Dioctadecanoyl-sn-glycero-3-phosphocholine (DSPC) liposomes. Curcumin strongly partition into liquid crystalline phase compared to solid gel phase of DSPC liposomes. Variation of fluorescence intensity of curcumin associated with liposomes with temperature successfully determines phase transition temperature of DSPC liposomes. However, at higher molar ratio curcumin can influence phase transition temperature by intercalating into deep hydrophobic layer of liposomes and facilitating fusion of two membrane phases. Rhamnolipids (RLs) are recently being applied for various biomedical applications. Here, we have explored new insight on intercalation of rhamnolipids with DSPC liposomes. Intercalation of rhamnolipids exceptionally increases partition of curcumin into solid gel phase of DSPC liposomes, whereas this increase is moderate in liquid crystalline phase. Fluorescence quenching study establishes that permeability and fluidity of the DSPC liposomes are enhanced in the presence of RLs. Membrane permeability and fluidity can be improved further by increasing the percentage of RLs in DSPC liposomes. The phase transition temperature of DSPC liposomes decreases with increase in percentage of RLs in DSPC liposomes by encouraging fusion between solid gel and liquid crystalline phases. Intercalation of RLs is found to further boost stability of drug, curcumin, in DSPC liposomes. Thus, mixing RLs with DSPC liposomes could potentially serve as a good candidate for drug delivery application. Copyright © 2016 Elsevier B.V. All rights reserved.

Estimation of the climate change impact on a catchment water balance using an ensemble of GCMs

NASA Astrophysics Data System (ADS)

Reshmidevi, T. V.; Nagesh Kumar, D.; Mehrotra, R.; Sharma, A.

2018-01-01

This work evaluates the impact of climate change on the water balance of a catchment in India. Rainfall and hydro-meteorological variables for current (20C3M scenario, 1981-2000) and two future time periods: mid of the 21st century (2046-2065) and end of the century (2081-2100) are simulated using Modified Markov Model-Kernel Density Estimation (MMM-KDE) and k-nearest neighbor downscaling models. Climate projections from an ensemble of 5 GCMs (MPI-ECHAM5, BCCR-BCM2.0, CSIRO-mk3.5, IPSL-CM4, and MRI-CGCM2) are used in this study. Hydrologic simulations for the current as well as future climate scenarios are carried out using Soil and Water Assessment Tool (SWAT) integrated with ArcGIS (ArcSWAT v.2009). The results show marginal reduction in runoff ratio, annual streamflow and groundwater recharge towards the end of the century. Increased temperature and evapotranspiration project an increase in the irrigation demand towards the end of the century. Rainfall projections for the future shows marginal increase in the annual average rainfall. Short and moderate wet spells are projected to decrease, whereas short and moderate dry spells are projected to increase in the future. Projected reduction in streamflow and groundwater recharge along with the increase in irrigation demand is likely to aggravate the water stress in the region under the future scenario.

Advances in the Breeding and Genetics of Heat Tolerance to Alleviate the Effects of Climate Change, with a Focus on Common Bean

USDA-ARS?s Scientific Manuscript database

Crop plants are broadly sensitive to high ambient temperatures during reproductive development while breeding efforts are helping to alleviate the impact of heat stress. Common bean, Phaseolus vulgaris L., is sensitive to moderately high ambient temperature, where temperatures greater than 25C have ...

A study of the association with blood pressure difference causing body temperature ≥37·5°C and hypertension in department of primary care.

PubMed

Shinji, Maeda

2013-11-01

Previous studies reported the relationship between significant blood pressure difference (ΔBP) and early atherosclerotic markers. Although it is known that body temperature is associated with BP and blood flow, as measured on Korotkoff sound graph (KSG), as well as heart rate and sympathetic nerve activity, it remains unclear whether moderate fever (≥37·5°C) can be caused by significant ΔBP. ΔBP was calculated by subtracting the BP of the left arm from that of the right arm. The aim of our study was to investigate whether an association exists among ΔBP, body temperature, hypertension and KSG area ratio in 1802 new outpatients examined in a seated position in routine clinical practice. Our study documented that absolute systolic blood pressure difference (|ΔSBP|) ≥ 10 mmHg (observed in 14·6% of the patients) was associated with a significantly higher heart rate, moderate fever, tachycardia and hypertension. In multivariate analysis, the odds ratios (ORs) of |ΔSBP| ≥ 10 mmHg showed significant associated markers of body temperature and hypertension, while the ORs of KSG area ratio ≥ 170% showed significant associated markers of sex, age, body temperature, hypertension, diabetes mellitus, prior vascular event and smoking. In conclusion, our study of new outpatients in the department of primary care demonstrated that |ΔSBP| ≥ 10 mmHg and KSG area ratio ≥ 170% were associated with moderate fever and hypertension. Furthermore, our study suggests that the association of moderate fever with |ΔSBP| ≥ 10 mmHg and KSG area ratio ≥ 170% is physiologic as well as pathologic. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Surfer's ear: external auditory exostoses are more prevalent in cold water surfers.

PubMed

Kroon, David F; Lawson, M Louise; Derkay, Craig S; Hoffmann, Karen; McCook, Joe

2002-05-01

The study goal was to demonstrate the prevalence and severity of external auditory exostoses (EAEs) in a population of surfers and to examine the relationship between these lesions and the length of time surfed as well as water temperature in which the swimmers surfed. It was hypothesized that subjects who predominantly surfed in colder waters had more frequent and more severe exostoses. Two hundred two avid surfers (91% male and 9% female, median age 17 years) were included in the study. EAEs were graded based on the extent of external auditory canal patency; grades of normal (100% patency), mild (66% to 99% patency), and moderate-severe (<66% patency) were assigned. Otoscopic findings were correlated with data collected via questionnaires that detailed surfing habits. There was a 38% overall prevalence of EAEs, with 69% of lesions graded as mild and 31% graded as moderate-severe. Professional surfers (odds ratio 3.8) and those subjects who surfed predominantly in colder waters (odds ratio 5.8) were found to be at a significantly increased risk for the development of EAEs. The number of years surfed was also found to be significant, increasing one's risk for developing an exostosis by 12% per year and for developing more severe lesions by 10% per year. Individuals who had moderate-severe EAEs were significantly more likely to be willing to surf in colder waters than were those who had mild EAEs (odds ratio 4.3). EAEs are more prevalent in cold water surfers, and additional years surfing increase one's risk not only for developing an EAE but also for developing more severe lesions.

Deglacial Warming and Wetting of Northern Alaska

NASA Astrophysics Data System (ADS)

Daniels, W.; Russell, J. M.; Longo, W. M.; Giblin, A. E.; Holland-Stergar, P.; Morrill, C.; Huang, Y.

2015-12-01

Aeolian sand dunes swept across northern Alaska during the last glacial maximum. Today, summer temperatures are moderate and soils can remain waterlogged all summer long. How did the transition from a cold and dry glacial to a warm and wet interglacial take place? To answer this question we reconstructed temperature and precipitation changes during the last deglaciation using biomarker hydrogen isotopes from a new 28,000 year-long sediment core from Lake E5, located in the central Brooks Range of Alaska. We use terrestrial leaf waxes (dDterr, C28-acid), informed by dD measurements of modern vegetation, to infer dD of precipitation, an indicator of relative temperature change. Biomarkers from aquatic organisms (dDaq, C18-acid) are used as a proxy for lake water isotopes. The offset between the two (eterr-aq) is used to infer relative changes in evaporative enrichment of lake water, and by extension, moisture balance. dDterr during the last glacial period was -282‰ compared to -258‰ during the Holocene, suggesting a 5.6 ± 2.7 °C increase in summer temperature using the modern local temperature-dD relationship. Gradual warming began at ~18.5 ka, and temperature increased abruptly at 11.5 ka, at the end of the Younger Dryas. Warming peaked in the early Holocene from 11.5 to 9.1 ka, indicating a Holocene thermal maximum associated with peak summer insolation. The eterr-aq supports a dry LGM and moist Holocene. Other sediment proxies (TIC, TOC, redox-sensitive elements) support the eterr-aq, and reveal a shift to more positive P-E beginning around 17 ka, suggesting rising temperature led increases in precipitation during the last deglaciation. Moreover, differing patterns of dDterr and eterr-aq during the deglaciation suggest that the relationship between temperature and precipitation changed through time. Such decoupling, likely due to regional atmospheric reorganization as the Laurentide ice sheet waned, illustrates the importance of atmospheric dynamics in controlling Alaskan climate.

Daily ambient temperature and renal colic incidence in Guangzhou, China: a time-series analysis

NASA Astrophysics Data System (ADS)

Yang, Changyuan; Chen, Xinyu; Chen, Renjie; Cai, Jing; Meng, Xia; Wan, Yue; Kan, Haidong

2016-08-01

Few previous studies have examined the association between temperature and renal colic in developing regions, especially in China, the largest developing country in the world. We collected daily emergency ambulance dispatches (EADs) for renal colic from Guangzhou Emergency Center from 1 January 2008 to 31 December 2012. We used a distributed-lag nonlinear model in addition to the over-dispersed generalized additive model to investigate the association between daily ambient temperature and renal colic incidence after controlling for seasonality, humidity, public holidays, and day of the week. We identified 3158 EADs for renal colic during the study period. This exposure-response curve was almost flat when the temperature was low and moderate and elevated when the temperature increased over 21 °C. For heat-related effects, the significant risk occurred on the concurrent day and diminished until lag day 7. The cumulative relative risk of hot temperatures (90th percentile) and extremely hot temperatures (99th percentile) over lag days 0-7 was 1.92 (95 % confidence interval, 1.21, 3.05) and 2.45 (95 % confidence interval, 1.50, 3.99) compared with the reference temperature of 21 °C. This time-series analysis in Guangzhou, China, suggested a nonlinear and lagged association between high outdoor temperatures and daily EADs for renal colic. Our findings might have important public health significance to prevent renal colic.

Temperature oscillations near natural nuclear reactor cores and the potential for prebiotic oligomer synthesis.

PubMed

Adam, Zachary R

2016-06-01

Geologic settings capable of driving prebiotic oligomer synthesis reactions remain a relatively unexplored aspect of origins of life research. Natural nuclear reactors are an example of Precambrian energy sources that produced unique temperature fluctuations. Heat transfer models indicate that water-moderated, convectively-cooled natural fission reactors in porous host rocks create temperature oscillations that resemble those employed in polymerase chain reaction (PCR) devices to artificially amplify oligonucleotides. This temperature profile is characterized by short-duration pulses up to 70-100 °C, followed by a sustained period of temperatures in the range of 30-70 °C, and finally a period of relaxation to ambient temperatures until the cycle is restarted by a fresh influx of pore water. For a given reactor configuration, temperature maxima and the time required to relax to ambient temperatures depend most strongly on the aggregate effect of host rock permeability in decreasing the thermal expansion and increasing the viscosity and evaporation temperature of the pore fluids. Once formed, fission-fueled reactors can sustain multi-kilowatt-level power production for 10(5)-10(6) years, ensuring microenvironmental longevity and chemical output. The model outputs indicate that organic synthesis on young planetary bodies with a sizeable reservoir of fissile material can involve more sophisticated energy dissipation pathways than modern terrestrial analog settings alone would suggest.

Cellulase stability, adsorption/desorption profiles and recycling during successive cycles of hydrolysis and fermentation of wheat straw.

PubMed

Rodrigues, Ana Cristina; Felby, Claus; Gama, Miguel

2014-03-01

The potential of enzymes recycling after hydrolysis and fermentation of wheat straw under a variety of conditions was investigated, monitoring the activity of the enzymes in the solid and liquid fractions, using low molecular weight substrates. A significant amount of active enzymes could be recovered by recycling the liquid phase. In the early stage of the process, enzyme adsorb to the substrate, then gradually returning to the solution as the saccharification proceeds. At 50°C, normally regarded as an acceptable operational temperature for saccharification, the enzymes (Celluclast) significantly undergo thermal deactivation. The hydrolysis yield and enzyme recycling efficiency in consecutive recycling rounds can be increased by using high enzyme loadings and moderate temperatures. Indeed, the amount of enzymes in the liquid phase increased with its thermostability and hydrolytic efficiency. This study contributes towards developing effective enzymes recycling strategies and helping to reduce the enzyme costs on bioethanol production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cooling interventions for athletes: An overview of effectiveness, physiological mechanisms, and practical considerations

PubMed Central

Bongers, Coen C. W. G.; Hopman, Maria T. E.; Eijsvogels, Thijs M. H.

2017-01-01

ABSTRACT Exercise-induced increases in core body temperature could negative impact performance and may lead to development of heat-related illnesses. The use of cooling techniques prior (pre-cooling), during (per-cooling) or directly after (post-cooling) exercise may limit the increase in core body temperature and therefore improve exercise performance. The aim of the present review is to provide a comprehensive overview of current scientific knowledge in the field of pre-cooling, per-cooling and post-cooling. Based on existing studies, we will discuss 1) the effectiveness of cooling interventions, 2) the underlying physiological mechanisms and 3) practical considerations regarding the use of different cooling techniques. Furthermore, we tried to identify the optimal cooling technique and compared whether cooling-induced performance benefits are different between cool, moderate and hot ambient conditions. This article provides researchers, physicians, athletes and coaches with important information regarding the implementation of cooling techniques to maintain exercise performance and to successfully compete in thermally stressful conditions. PMID:28349095

Effect of Environmental Exposures on Fatigue Life of P/M Disk Superalloys

NASA Technical Reports Server (NTRS)

Draper, Susan

2011-01-01

As the temperature capability of Ni-base superalloy powder metallurgy disks is steadily increased, environmental resistance and protection of advanced nickel-based turbine disk components are becoming increasingly important. Localized surface hot corrosion attack and damage from oxidation have been shown to impair disk fatigue life and may eventually limit disk operating temperatures. NASA Research Announcement (NRA) contracts have been awarded to GE Aviation and Honeywell Aerospace to separately develop fatigue resistant metallic and ceramic coatings for corrosion resistance and the corrosion/fatigue results of selected coatings will be presented. The microstructural response of a bare ME3 disk superalloy has been evaluated for moderate (704 C) and aggressive (760-816 C) oxidizing exposures up to 2,020 hours. Cross section analysis reveals sub-surface damage (significant for aggressive exposures) that consists of Al2O3 "fingers", interfacial voids, a recrystallized precipitate-free layer and GB carbide dissolution. The effects of a Nichrome corrosion coating on this microstructural response will also be presented.

Ultrastructural study of mitochondrial damage in CHO cells exposed to hyperthermia.

PubMed

Cole, A; Armour, E P

1988-09-01

A unique direct-view stereo electron microscope technique was used to visualize the structure and three-dimensional distributions of mitochondria in CHO cells in situ following hyperthermic treatments. Aberrations induced by various heating regimens were recorded. The protocol included a trypsin digestion that may have enhanced the expression of the initial heat damage. The developed damage was observed as increasing levels of mitochondrial distortion, swelling, and dissociation. Minimal damage was induced at 42 degrees C for exposures of up to 4 h, while significant damage was induced at 43 degrees C for exposures of more than 30 min and at 45 degrees C for exposures of more than 10 min. For moderate exposures, a partial recovery of mitochondrial integrity was observed when the heat treatment was followed by incubation at 37 degrees C for 24 h. Mitochondrial damage was related to the heat dose in that increasing treatment temperature resulted in greater damage, but when compared to cell survival the damage did not parallel cell killing under all time-temperature conditions.

Slip analysis of squeezing flow using doubly stratified fluid

NASA Astrophysics Data System (ADS)

Ahmad, S.; Farooq, M.; Javed, M.; Anjum, Aisha

2018-06-01

The non-isothermal flow is modeled and explored for squeezed fluid. The influence of velocity, thermal and solutal slip effects on transport features of squeezed fluid are analyzed through Darcy porous channel when fluid is moving due to squeezing of upper plate towards the stretchable lower plate. Dual stratification effects are illustrated in transport equations. A similarity analysis is performed and reduced governing flow equations are solved using moderated and an efficient convergent approach i.e. Homotopic technique. The significant effects of physical emerging parameters on flow velocity, temperature and fluid concentration are reporting through various plots. Graphical explanations for drag force, Nusselt and Sherwood numbers are stated and examined. The results reveal that minimum velocity field occurs near the plate, whereas it increases far away from the plate for strong velocity slip parameter. Furthermore, temperature and fluid concentration significantly decreases with increased slip effects. The current analysis is applicable in some advanced technological processes and industrial fluid mechanics.

Moderate Dilution of Copper Slag by Natural Gas

NASA Astrophysics Data System (ADS)

Zhang, Bao-jing; Zhang, Ting-an; Niu, Li-ping; Liu, Nan-song; Dou, Zhi-he; Li, Zhi-qiang

2018-01-01

To enable use of copper slag and extract the maximum value from the contained copper, an innovative method of reducing moderately diluted slag to smelt copper-containing antibacterial stainless steel is proposed. This work focused on moderate dilution of copper slag using natural gas. The thermodynamics of copper slag dilution and ternary phase diagrams of the slag system were calculated. The effects of blowing time, temperature, matte settling time, and calcium oxide addition were investigated. The optimum reaction conditions were identified to be blowing time of 20 min, reaction temperature of 1250°C, settling time of 60 min, CaO addition of 4% of mass of slag, natural gas flow rate of 80 mL/min, and outlet pressure of 0.1 MPa. Under these conditions, the Fe3O4 and copper contents of the residue were 7.36% and 0.50%, respectively.

Temperature measurement method using temperature coefficient timing for resistive or capacitive sensors

DOEpatents

Britton, Jr., Charles L.; Ericson, M. Nance

1999-01-01

A method and apparatus for temperature measurement especially suited for low cost, low power, moderate accuracy implementation. It uses a sensor whose resistance varies in a known manner, either linearly or nonlinearly, with temperature, and produces a digital output which is proportional to the temperature of the sensor. The method is based on performing a zero-crossing time measurement of a step input signal that is double differentiated using two differentiators functioning as respective first and second time constants; one temperature stable, and the other varying with the sensor temperature.

Hemodynamic Responses to Head and Neck Cooling

NASA Technical Reports Server (NTRS)

Ku, Yu-Tsuan E.; Carbo, Jorge E.; Montgomery, Leslie D.; Webbon, Bruce W.

1994-01-01

Personal thermoregulatory systems which provide head and neck cooling are used in the industrial and aerospace environments to alleviate thermal stress. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objective of this study was to measure the scalp temperature and circulatory responses during use of one commercially available thermal control system. The Life Support Systems, Inc. Mark VII portable cooling system and a liquid cooling helmet were used in this study. Two EEG electrodes and one skin temperature transducer were placed on the anterior midline of the scalp to measure the scalp blood and temperature. Blood flow was measured using a bipolar impedance rheograph. Ten subjects, seated in an upright position at normal room temperature, were tested at high, medium, moderate, moderate-low and low coolant temperatures. Scalp blood flow was recorded continuously using a computer data acquisition system with a sampling frequency of 200 Hz. Scalp temperature and cooling helmet Inlet temperature was logged periodically during the test period. This study quantifies the effect of head cooling upon scalp temperature and blood flow. These data may also be used to select operational specifications of the head cooling system for biomedical applications such as the treatment of migraine headaches, scalp cooling during chemotherapy, and cooling of multiple sclerosis patients.

Mediation pathways and effects of green structures on respiratory mortality via reducing air pollution

NASA Astrophysics Data System (ADS)

Shen, Yu-Sheng; Lung, Shih-Chun Candice

2017-02-01

Previous studies have shown both health and environmental benefits of green spaces, especially in moderating temperature and reducing air pollution. However, the characteristics of green structures have been overlooked in previous investigations. In addition, the mediation effects of green structures on respiratory mortality have not been assessed. This study explores the potential mediation pathways and effects of green structure characteristics on respiratory mortality through temperature, primary and secondary air pollutants separately using partial least squares model with data from Taiwan. The measurable characteristics of green structure include the largest patch percentage, landscape proportion, aggregation, patch distance, and fragmentation. The results showed that mortality of pneumonia and chronic lower respiratory diseases could be reduced by minimizing fragmentation and increasing the largest patch percentage of green structure, and the mediation effects are mostly through reducing air pollutants rather than temperature. Moreover, a high proportion of but fragmented green spaces would increase secondary air pollutants and enhance health risks; demonstrating the deficiency of traditional greening policy with primary focus on coverage ratio. This is the first research focusing on mediation effects of green structure characteristics on respiratory mortality, revealing that appropriate green structure planning can be a useful complementary strategy in environmental health management.

Mediation pathways and effects of green structures on respiratory mortality via reducing air pollution.

PubMed

Shen, Yu-Sheng; Lung, Shih-Chun Candice

2017-02-23

Previous studies have shown both health and environmental benefits of green spaces, especially in moderating temperature and reducing air pollution. However, the characteristics of green structures have been overlooked in previous investigations. In addition, the mediation effects of green structures on respiratory mortality have not been assessed. This study explores the potential mediation pathways and effects of green structure characteristics on respiratory mortality through temperature, primary and secondary air pollutants separately using partial least squares model with data from Taiwan. The measurable characteristics of green structure include the largest patch percentage, landscape proportion, aggregation, patch distance, and fragmentation. The results showed that mortality of pneumonia and chronic lower respiratory diseases could be reduced by minimizing fragmentation and increasing the largest patch percentage of green structure, and the mediation effects are mostly through reducing air pollutants rather than temperature. Moreover, a high proportion of but fragmented green spaces would increase secondary air pollutants and enhance health risks; demonstrating the deficiency of traditional greening policy with primary focus on coverage ratio. This is the first research focusing on mediation effects of green structure characteristics on respiratory mortality, revealing that appropriate green structure planning can be a useful complementary strategy in environmental health management.

The blooms of a cyanobacterium, Microcystis cf. aeruginosa in a severely polluted estuary, the Golden Horn, Turkey

NASA Astrophysics Data System (ADS)

Taş, Seyfettin; Okuş, Erdoğan; Aslan-Yılmaz, Aslı

2006-07-01

The distribution of toxic cyanobacterium Microcystis cf. aeruginosa in the severely polluted Golden Horn Estuary was studied from 1998 to 2000. Microcystis persisted at the upper estuary where the water circulation was poor and values ranged between 2.9 × 10 4 and 2.7 × 10 6 cells ml -1 throughout the study. Simultaneously measured physical (salinity, temperature, rainfall and secchi disc) and chemical parameters (nutrients and dissolved oxygen) were evaluated together with Microcystis data. Although the Microcystis blooms generally occur in summer due to the increase in temperature, the blooms were recorded in winter in the present study. The abundance of Microcystis depended on the variations in salinity and both blooms were recorded below S = 2. A moderate partial correlation between Microcystis abundance and salinity was detected in the presence of temperature, dissolved oxygen and precipitation data ( r = -0.561, p = 0.002). The M. cf. aeruginosa abundance was low in the summer when the salinity was higher than winter. A remarkable increase in the eukaryotic phytoplankton abundance following the improvements in the water quality of the estuary occurred, whilst the Microcystis abundance remained below bloom level.

Stabilization of a tetrameric malate dehydrogenase by introduction of a disulfide bridge at the dimer-dimer interface.

PubMed

Bjørk, Alexandra; Dalhus, Bjørn; Mantzilas, Dimitrios; Eijsink, Vincent G H; Sirevåg, Reidun

2003-12-05

Malate dehydrogenase (MDH) from the moderately thermophilic bacterium Chloroflexus aurantiacus (CaMDH) is a tetrameric enzyme, while MDHs from mesophilic organisms usually are dimers. To investigate the potential contribution of the extra dimer-dimer interface in CaMDH with respect to thermal stability, we have engineered an intersubunit disulfide bridge designed to strengthen dimer-dimer interactions. The resulting mutant (T187C, containing two 187-187 disulfide bridges in the tetramer) showed a 200-fold increase in half-life at 75 degrees C and an increase of 15 deg. C in apparent melting temperature compared to the wild-type. The crystal structure of the mutant (solved at 1.75 A resolution) was essentially identical with that of the wild-type, with the exception of the added inter-dimer disulfide bridge and the loss of an aromatic intra-dimer contact. Remarkably, the mutant and the wild-type had similar temperature optima and activities at their temperature optima, thus providing a clear case of uncoupling of thermal stability and thermoactivity. The results show that tetramerization may contribute to MDH stability to an extent that depends strongly on the number of stabilizing interactions in the dimer-dimer interface.

"Cooking the sample": radiofrequency induced heating during solid-state NMR experiments.

PubMed

d'Espinose de Lacaillerie, Jean-Baptiste; Jarry, Benjamin; Pascui, Ovidiu; Reichert, Detlef

2005-09-01

Dissipation of radiofrequency (RF) energy as heat during continuous wave decoupling in solid-state NMR experiment was examined outside the conventional realm of such phenomena. A significant temperature increase could occur while performing dynamic NMR measurements provided the sample contains polar molecules and the sequence calls for relatively long applications of RF power. It was shown that the methyl flip motion in dimethylsulfone (DMS) is activated by the decoupling RF energy conversion to heat during a CODEX pulse sequence. This introduced a significant bias in the correlation time-temperature dependency measurement used to obtain the activation energy of the motion. By investigating the dependency of the temperature increase in hydrated lead nitrate on experimental parameters during high-power decoupling one-pulse experiments, the mechanisms for the RF energy deposition was identified. The samples were heated due to dissipation of the energy absorbed by dielectric losses, a phenomenon commonly known as "microwave" heating. It was thus established that during solid-state NMR experiments at moderate B0 fields, RF heating could lead to the heating of samples containing polar molecules such as hydrated polymers and inorganic solids. In particular, this could result in systematic errors for slow dynamics measurements by solid-state NMR.

The visual ecology of a deep-sea fish, the escolar Lepidocybium flavobrunneum (Smith, 1843)†

PubMed Central

Landgren, Eva; Fritsches, Kerstin; Brill, Richard; Warrant, Eric

2014-01-01

Escolar (Lepidocybium flavobrunneum, family Gempylidae) are large and darkly coloured deep-sea predatory fish found in the cold depths (more than 200 m) during the day and in warm surface waters at night. They have large eyes and an overall low density of retinal ganglion cells that endow them with a very high optical sensitivity. Escolar have banked retinae comprising six to eight layers of rods to increase the optical path length for maximal absorption of the incoming light. Their retinae possess two main areae of higher ganglion cell density, one in the ventral retina viewing the dorsal world above (with a moderate acuity of 4.6 cycles deg−1), and the second in the temporal retina viewing the frontal world ahead. Electrophysiological recordings of the flicker fusion frequency (FFF) in isolated retinas indicate that escolar have slow vision, with maximal FFF at the highest light levels and temperatures (around 9 Hz at 23°C) which fall to 1–2 Hz in dim light or cooler temperatures. Our results suggest that escolar are slowly moving sit-and-wait predators. In dim, warm surface waters at night, their slow vision, moderate dorsal resolution and highly sensitive eyes may allow them to surprise prey from below that are silhouetted in the downwelling light. PMID:24395966

Pyridostigmine bromide does not alter thermoregulation during exercise in cold air

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

Roberts, D.E.; Sawka, M.N.; Young, A.J.

1994-12-31

This study examined the effects of acute and chronic pyridostigmine bromide (PB) administration on thermoregulatory and metabolic responses to exercise in cold air (5 C). Seven healthy men completed two 7-day trials in a double-blind, crossover experimental design: during one trial they received PB (30 mg three times daily) and during the other trial they received placebo. For each trial, subjects attempted four (3 h) exercise tests: low-intensity exercise (25% Vo2max) and moderate- intensity exercise (-50% Vo2max), on days 2 and 3 and again on days 6 and 7. Metabolic rate, body temperatures, and venous blood samples were obtained beforemore » and during exercise. Red blood cell acerylcholinesterase inhibition induced by PB increased (p < 0.05) from 34% on day I to 43% on days 3-7 Metabolic rate, body temperatures, and regional heat conductance responses were not different between trials. Plasma glucose, glycerol, free fatty acid, lactate, sodium, and potassium concentrations were not different between trials. In addition. differences were not found between acute and chronic experiments for any thermoregulatory or metabolic responses. These findings demonstrate that the PB dosage used by military personnel, as a pharmacological defense against nerve-agent poisoning. should not cause any adverse thermoregulatory or metabolic effects during moderate activity in cold climates.« less

Projection of heat waves variation over a warming climate in China

NASA Astrophysics Data System (ADS)

Yue, X.; Wu, S.; Pan, T.

2016-12-01

Heat waves (HW) have adverse impacts on economies, human health, societies and environment, which have been observed around the world and are expected to increase in a warming climate. However, the variations of HW under climate change over China are not clear yet. Using the HadGEM2-ES RCP4.5 and RCP8.5 daily maximum temperature and humidity dataset, variation of heat waves in China for 2021-2050 comparing to 1991-2000 as baseline were analyzed. The CMA-HI (Heat Index standardized by China Meteorological Administration) index was used to calculate the frequency and intensity of head waves. This paper classified the HW into three intensity levels including mild HW, moderate HW and severe HW , and defined a heat wave event (HWE) as that CMA-HI are all above or equal to 2.8 and keep at a intensity level more than five consecutive days. Results show that during 2021to 2050, the distribution area, frequency and duration of each intensity level have an increasing trend over China, and those of severe HW will increase mostly. The distribution area of mild, moderate and severe HW will increase 18%, 22%, 35% respectively. Average HWE frequency of each level will concentrate on 0.5-1instead of 0-0.3 in baseline period. Maximum frequency of each intensity can reach to almost 3 times a year. During 1991-2000, the average frequency of mild HW, moderate HW and severe HW kept a downward sequence. But it will change to increase in the future, and the shift occurs during 2031-2040. In addition, only severe HW duration will increase in the future. Its average value will increase from 9days to 13days, and keep a maximum duration of 42days.While the average duration of mild HW and moderate HW just keep almost 6 days and 8 days as usual. Regionally, both the frequency and duration will keep high value in the region of eastern China, central China, southern China and central Xinjiang autonomous region in the future. And only severe HW has a great change in distribution. Under RCP 8.5 climate scenario, China will suffer much more severe heat waves. The result of prediction of heat waves can give scientific basis to climate change risk management and adaptation strategies.

Fragility and glass transition for binary mixtures of 1,2-propanediol and LiBF4

NASA Astrophysics Data System (ADS)

Terashima, Y.; Mori, M.; Sugimoto, N.; Takeda, K.

2014-04-01

The fragility and glass transition for binary mixtures of 1,2-propanediol and LiBF4 were investigated by measuring the heating rate dependence of glass transition temperature (Tg) using differential scanning calorimetry. With increasing LiBF4 mole fraction, x, up to 0.25, fragility, m, increased rapidly from 53 to 85, and then remained approximately unchanged for x > 0.25. The concentration dependences of Tg and heat capacity jump at Tg also showed anomalies around x = 0.25. We suggest this mixture transformed from a moderate to quite fragile liquid at x = 0.25 because of a structural change from a hydrogen-bonding- to ionic-interaction-dominant system.

A common thermal niche among geographically diverse populations of the widely distributed tree species Eucalyptus tereticornis: No evidence for adaptation to climate-of-origin.

PubMed

Drake, John E; Vårhammar, Angelica; Kumarathunge, Dushan; Medlyn, Belinda E; Pfautsch, Sebastian; Reich, Peter B; Tissue, David T; Ghannoum, Oula; Tjoelker, Mark G

2017-12-01

Impacts of climate warming depend on the degree to which plants are constrained by adaptation to their climate-of-origin or exhibit broad climatic suitability. We grew cool-origin, central and warm-origin provenances of Eucalyptus tereticornis in an array of common temperature environments from 18 to 35.5°C to determine if this widely distributed tree species consists of geographically contrasting provenances with differentiated and narrow thermal niches, or if provenances share a common thermal niche. The temperature responses of photosynthesis, respiration, and growth were equivalent across the three provenances, reflecting a common thermal niche despite a 2,200 km geographic distance and 13°C difference in mean annual temperature at seed origin. The temperature dependence of growth was primarily mediated by changes in leaf area per unit plant mass, photosynthesis, and whole-plant respiration. Thermal acclimation of leaf, stem, and root respiration moderated the increase in respiration with temperature, but acclimation was constrained at high temperatures. We conclude that this species consists of provenances that are not differentiated in their thermal responses, thus rejecting our hypothesis of adaptation to climate-of-origin and suggesting a shared thermal niche. In addition, growth declines with warming above the temperature optima were driven by reductions in whole-plant leaf area and increased respiratory carbon losses. The impacts of climate warming will nonetheless vary across the geographic range of this and other such species, depending primarily on each provenance's climate position on the temperature response curves for photosynthesis, respiration, and growth. © 2017 John Wiley & Sons Ltd.

Predicted effects of climate warming on the distribution of 50 stream fishes in Wisconsin, U.S.A.

USGS Publications Warehouse

Lyons, J.; Stewart, J.S.; Mitro, M.

2010-01-01

Summer air and stream water temperatures are expected to rise in the state of Wisconsin, U.S.A., over the next 50 years. To assess potential climate warming effects on stream fishes, predictive models were developed for 50 common fish species using classification-tree analysis of 69 environmental variables in a geographic information system. Model accuracy was 56.0-93.5% in validation tests. Models were applied to all 86 898 km of stream in the state under four different climate scenarios: current conditions, limited climate warming (summer air temperatures increase 1?? C and water 0.8?? C), moderate warming (air 3?? C and water 2.4?? C) and major warming (air 5?? C and water 4?? C). With climate warming, 23 fishes were predicted to decline in distribution (three to extirpation under the major warming scenario), 23 to increase and four to have no change. Overall, declining species lost substantially more stream length than increasing species gained. All three cold-water and 16 cool-water fishes and four of 31 warm-water fishes were predicted to decline, four warm-water fishes to remain the same and 23 warm-water fishes to increase in distribution. Species changes were predicted to be most dramatic in small streams in northern Wisconsin that currently have cold to cool summer water temperatures and are dominated by cold-water and cool-water fishes, and least in larger and warmer streams and rivers in southern Wisconsin that are currently dominated by warm-water fishes. Results of this study suggest that even small increases in summer air and water temperatures owing to climate warming will have major effects on the distribution of stream fishes in Wisconsin. ?? 2010 The Authors. Journal of Fish Biology ?? 2010 The Fisheries Society of the British Isles.

Predicted effects of climate warming on the distribution of 50 stream fishes in Wisconsin, U.S.A.

USGS Publications Warehouse

Stewart, Jana S.; Lyons, John D.; Matt Mitro,

2010-01-01

Summer air and stream water temperatures are expected to rise in the state of Wisconsin, U.S.A., over the next 50 years. To assess potential climate warming effects on stream fishes, predictive models were developed for 50 common fish species using classification-tree analysis of 69 environmental variables in a geographic information system. Model accuracy was 56·0–93·5% in validation tests. Models were applied to all 86 898 km of stream in the state under four different climate scenarios: current conditions, limited climate warming (summer air temperatures increase 1° C and water 0·8° C), moderate warming (air 3° C and water 2·4° C) and major warming (air 5° C and water 4° C). With climate warming, 23 fishes were predicted to decline in distribution (three to extirpation under the major warming scenario), 23 to increase and four to have no change. Overall, declining species lost substantially more stream length than increasing species gained. All three cold-water and 16 cool-water fishes and four of 31 warm-water fishes were predicted to decline, four warm-water fishes to remain the same and 23 warm-water fishes to increase in distribution. Species changes were predicted to be most dramatic in small streams in northern Wisconsin that currently have cold to cool summer water temperatures and are dominated by cold-water and cool-water fishes, and least in larger and warmer streams and rivers in southern Wisconsin that are currently dominated by warm-water fishes. Results of this study suggest that even small increases in summer air and water temperatures owing to climate warming will have major effects on the distribution of stream fishes in Wisconsin.

Moderate Cortical Cooling Eliminates Thalamocortical Silent States during Slow Oscillation.

PubMed

Sheroziya, Maxim; Timofeev, Igor

2015-09-23

Reduction in temperature depolarizes neurons by a partial closure of potassium channels but decreases the vesicle release probability within synapses. Compared with cooling, neuromodulators produce qualitatively similar effects on intrinsic neuronal properties and synapses in the cortex. We used this similarity of neuronal action in ketamine-xylazine-anesthetized mice and non-anesthetized mice to manipulate the thalamocortical activity. We recorded cortical electroencephalogram/local field potential (LFP) activity and intracellular activities from the somatosensory thalamus in control conditions, during cortical cooling and on rewarming. In the deeply anesthetized mice, moderate cortical cooling was characterized by reversible disruption of the thalamocortical slow-wave pattern rhythmicity and the appearance of fast LFP spikes, with frequencies ranging from 6 to 9 Hz. These LFP spikes were correlated with the rhythmic IPSP activities recorded within the thalamic ventral posterior medial neurons and with depolarizing events in the posterior nucleus neurons. Similar cooling of the cortex during light anesthesia rapidly and reversibly eliminated thalamocortical silent states and evoked thalamocortical persistent activity; conversely, mild heating increased thalamocortical slow-wave rhythmicity. In the non-anesthetized head-restrained mice, cooling also prevented the generation of thalamocortical silent states. We conclude that moderate cortical cooling might be used to manipulate slow-wave network activity and induce neuromodulator-independent transition to activated states. Significance statement: In this study, we demonstrate that moderate local cortical cooling of lightly anesthetized or naturally sleeping mice disrupts thalamocortical slow oscillation and induces the activated local field potential pattern. Mild heating has the opposite effect; it increases the rhythmicity of thalamocortical slow oscillation. Our results demonstrate that slow oscillation can be influenced by manipulations to the properties of cortical neurons without changes in neuromodulation. Copyright © 2015 the authors 0270-6474/15/3513006-14$15.00/0.

Infection dynamics and acute phase response of an Actinobacillus pleuropneumoniae field isolate of moderate virulence in pigs.

PubMed

Gómez-Laguna, Jaime; Islas, Armando; Muñoz, Dennis; Ruiz, Alvaro; Villamil, Aura; Carrasco, Librado; Quezada, Manuel

2014-10-10

Actinobacillus pleuropneumoniae, the causative agent of porcine contagious pleuropneumonia (PCP), causes significant economic losses associated mainly with growth stunting of animals. Although serotypes can be distinguished according to their virulence, most of the studies are focused in A. pleuropneumoniae infections with virulent serotypes. There is little information regarding the role of acute phase proteins (APPs) and proinflammatory cytokines in infections with isolates of mild or moderate virulence. Thus, the present study aims to evaluate the kinetics of infection with an A. pleuropneumoniae serotype 6 (Ap6) field isolate of moderate virulence and the changes in the serum concentration of specific antibodies and different APPs and proinflammatory cytokines. Control animals showed no clinical signs or lesions throughout the study. Infected animals showed increased rectal temperature, respiratory distress and depression from 24hpi, and typical gross and microscopic lesions of PCP from 6hpi onwards. Ap6 was isolated from nasal swabs of four out of five inoculated animals at 24hpi, and from nasal swabs, tonsil and lung samples from all inoculated animals at 72hpi. Specific antibodies against Ap6 or changes in the serum concentration of IL-1β, IL-10 and TNF-α were not detected throughout the study. The serum concentration of IL-6 increased from 6hpi as well as serum A amyloid, C-reactive protein and haptoglobin from 24hpi onwards. Our results highlight the onset of the acute phase response after the infection with a field isolate of A. pleuropneumoniae of moderate virulence from 24hpi onwards which may be of interest in the study of the pathogenesis of this disease. Copyright © 2014 Elsevier B.V. All rights reserved.

Germ cell apoptosis and expression of Bcl-2 and Bax in porcine testis under normal and heat stress conditions.

PubMed

Fan, Xiaorui; Xi, Huaming; Zhang, Zhen; Liang, Yajun; Li, Qinghong; He, Junping

2017-04-01

The aim of this study was to examine whether an elevated ambient temperature (37-40°C) had an effect on the apoptosis of germ cells and the expression of Bcl-2 and Bax in porcine testis. Six boars were used. Three boars were subjected to an elevated ambient temperature (37-40°C, 7days, 3h per day) as a heat stress (HS) group. The other 3 boars were kept in a room temperature house (20-27°C) as a control group. All boars were castrated and the testes were harvested. TUNEL assay was used for the detection of apoptotic cells. Immunohistochemistry, Western blotting and quantitative real-time PCR were used to analyze protein and mRNA levels of Bcl-2 and Bax in response to heat treatment. The results showed that apoptotic signals increased under heat stress conditions compared with the control (P<0.01), and the cell types most affected by heat treatment were spermatocytes and spermatids. In both the control and experimental groups, Bcl-2 was expressed in the cytoplasm and nucleus of spermatogonia, spermatocytes and differentiating spermatids and Bcl-2 preferentially localized close to the seminiferous tubule's luminal surface in late spermatocytes and spermatids. Compared with the control group, the expression levels of Bcl-2 protein and mRNA significantly increased in heat treatment group, while the expression levels of Bax protein and mRNA did not show significant changes between the control and experimental group. Low to moderate Bax immunoreactivity staining was observed in all kinds of germ cells in the control group. Strong staining was observed in spermatogonia, and low to moderate Bax staining was observed in spermatocytes and spermatids. A redistribution of Bax from a cytoplasmic to perinuclear or nuclear localization could be observed in the spermatogonia, spermatocytes and spermatids obtained in the heat treated group. These results showed that elevated ambient temperatures induced germ cell apoptosis. In response to heat stress, the expression of Bcl-2 increased and a redistribution of Bax from a cytoplasmic to a perinuclear or nuclear localization. This indicates that Bcl-2 and Bax may be involved in regulation of germ cell apoptosis induced by heat stress in boars. Copyright © 2016. Published by Elsevier GmbH.

Spatial Characteristics of Geothermal Spring Temperatures and Discharge Rates in the Tatun Volcanic Area, Taiwan

NASA Astrophysics Data System (ADS)

Jang, C. S.; Liu, C. W.

2014-12-01

The Tatun volcanic area is the only potential volcanic geothermal region in the Taiwan island, and abundant in hot spring resources owing to stream water mixing with fumarolic gases. According to the Meinzer's classification, spring temperatures and discharge rates are the most important properties for characterizing spring classifications. This study attempted to spatially characterize spring temperatures and discharge rates in the Tatun volcanic area, Taiwanusing indicator kriging (IK). First, data on spring temperatures and discharge rates, which were collected from surveyed data of the Taipei City Government, were divided into high, moderate and low categories according to spring classification criteria, and the various categories were regarded as estimation thresholds. Then, IK was adopted to model occurrence probabilities of specified temperatures and discharge rates in springs, and to determine their classifications based on estimated probabilities. Finally, nine combinations were obtained from the classifications of temperatures and discharge rates in springs. Moreover, the combinations and features of spring water were spatially quantified according to seven sub-zones of spring utilization. A suitable and sustainable development strategy of the spring area was proposed in each sub-zone based on probability-based combinations and features of spring water.The research results reveal that the probability-based classifications using IK provide an excellent insight in exploring the uncertainty of spatial features in springs, and can provide Taiwanese government administrators with detailed information on sustainable spring utilization and conservation in the overexploited spring tourism areas. The sub-zones BT (Beitou), RXY (Rd. Xingyi), ZSL (Zhongshanlou) and LSK (Lengshuikeng) with high or moderate discharge rates are suitable to supply spring water for tourism hotels.Local natural hot springs should be planned in the sub-zones DBT (Dingbeitou), ZSL, XYK (Xiayoukeng), and MC (Macao) with low discharge rates, and low or moderate temperatures, particularly in riverbeds or valleys.Keywords: Spring; Temperature; Discharge rate; Indicator kriging; Uncertainty

Moderate-resolution sea surface temperature data for the Arctic Ocean Ecoregions

EPA Science Inventory

Sea surface temperature (SST) is an important environmental characteristic in determining the suitability and sustainability of habitats for marine organisms. Of particular interest is the fate of the Arctic Ocean, which provides critical habitat to commercially important fish (M...

Moderate-Resolution Sea Surface Temperature Data for the Nearshore North Pacific

EPA Science Inventory

Coastal sea surface temperature (SST) is an important environmental characteristic defining habitat suitability for nearshore marine and estuarine organisms. The purpose of this publication is to provide access to an easy-to-use coastal SST dataset for ecologists, biogeographers...

Designing of the Cooling Vest from Paraffin Compounds and Evaluation of its Impact Under Laboratory Hot Conditions.

PubMed

Yazdanirad, Saeid; Dehghan, Habibollah

2016-01-01

The phase change materials (PCMs) have the appropriate properties for controlling heat strain. One of the well-known PCMs is paraffin. This study aimed to design the cooling vest from the cheap commercial paraffin compound and evaluation of its effectiveness under laboratory hot conditions. the cooling vest was made of the polyester fabric and it had 17 aluminum packs. The each of aluminum packs was filled by 135 g of prepared paraffin with a proper melting point in the range of 15-35°C. an experimental study was conducted on ten male students under warm conditions (air temperature = 40°C, relative humidity = 40%) in a climatic chamber. Each participant was tested without cooling vest and with cooling in two activities rate on treadmill to include: light (2.8 km/h) and moderate (4.8 km/h). The time of this test was 30 min in each stage. During the test, the heart rate, the oral temperature, the skin temperature were measured every 4 min. Finally, data were analyzed using the Kolmogrov-Smirnov and repeated measurement ANOVA test in SPSS 16. The latent heat of the prepared paraffin compound and the peak of the melting point were 108 kJ/kg and 30°C, respectively. The mean and standard deviation of heart rate, oral temperature, and skin temperature with cooling vest in light activity were 103.9 (12.12) beat/min, 36.77 (0.32)°C, and 31.01 (1.96)°C and in moderate activity were 109.5 (12.57) beat/min, 36.79 (0.20)°C, and 29.69 (2.23)°C, respectively. There is a significant difference between parameters with a cooling vest and without cooling (P < 0.05). The designed cooling vest with low cost can be used to prevent thermal strain and to increase the physiological stability against the heat. However, the latent heat of this cooling vest was low.

Depth of artificial Burrowing Owl burrows affects thermal suitability and occupancy

USGS Publications Warehouse

Nadeau, Christopher P.; Conway, Courtney J.; Rathbun, Nathan

2015-01-01

Many organizations have installed artificial burrows to help bolster local Burrowing Owl (Athene cunicularia) populations. However, occupancy probability and reproductive success in artificial burrows varies within and among burrow installations. We evaluated the possibility that depth below ground might explain differences in occupancy probability and reproductive success by affecting the temperature of artificial burrows. We measured burrow temperatures from March to July 2010 in 27 artificial burrows in southern California that were buried 15–76 cm below the surface (measured between the surface and the top of the burrow chamber). Burrow depth was one of several characteristics that affected burrow temperature. Burrow temperature decreased by 0.03°C per cm of soil on top of the burrow. The percentage of time that artificial burrows provided a thermal refuge from above-ground temperature decreased with burrow depth and ranged between 50% and 58% among burrows. The percentage of time that burrow temperature was optimal for incubating females also decreased with burrow depth and ranged between 27% and 100% among burrows. However, the percentage of time that burrow temperature was optimal for unattended eggs increased with burrow depth and ranged between 11% and 95% among burrows. We found no effect of burrow depth on reproductive success across 21 nesting attempts. However, occupancy probability had a non-linear relationship with burrow depth. The shallowest burrows (15 cm) had a moderate probability of being occupied (0.46), burrows between 28 and 40 cm had the highest probability of being occupied (>0.80), and burrows >53 cm had the lowest probability of being occupied (<0.43). Burrowing Owls may prefer burrows at moderate depths because these burrows provide a thermal refuge from above-ground temperatures, and are often cool enough to allow females to leave eggs unattended before the onset of full-time incubation, but not too cool for incubating females that spend most of their time in the burrow during incubation. Our results suggest that depth is an important consideration when installing artificial burrows for Burrowing Owls. However, additional study is needed to determine the possible effects of burrow depth on reproductive success and on possible tradeoffs between the effects of burrow depth on optimal temperature and other factors, such as minimizing the risk of nest predation.

Response of a Habitat-Forming Marine Plant to a Simulated Warming Event Is Delayed, Genotype Specific, and Varies with Phenology

PubMed Central

Reynolds, Laura K.; DuBois, Katherine; Abbott, Jessica M.; Williams, Susan L.; Stachowicz, John J.

2016-01-01

Growing evidence shows that increasing global temperature causes population declines and latitudinal shifts in geographical distribution for plants living near their thermal limits. Yet, even populations living well within established thermal limits of a species may suffer as the frequency and intensity of warming events increase with climate change. Adaptive response to this stress at the population level depends on the presence of genetic variation in thermal tolerance in the populations in question, yet few data exist to evaluate this. In this study, we examined the immediate effects of a moderate warming event of 4.5°C lasting 5 weeks and the legacy effects after a 5 week recovery on different genotypes of the marine plant Zostera marina (eelgrass). We conducted the experiment in Bodega Bay, CA USA, where average summer water temperatures are 14–15°C, but extended warming periods of 17–18°C occur episodically. Experimental warming increased shoot production by 14% compared to controls held at ambient temperature. However, after returning temperature to ambient levels, we found strongly negative, delayed effects of warming on production: shoot production declined by 27% and total biomass decreased by 50% relative to individuals that had not been warmed. While all genotypes’ production decreased in the recovery phase, genotypes that grew the most rapidly under benign thermal conditions (control) were the most susceptible to the detrimental effects of warming. This suggests a potential tradeoff in relative performance at normal vs. elevated temperatures. Modest short-term increases in water temperature have potentially prolonged negative effects within the species’ thermal envelope, but genetic variation within these populations may allow for population persistence and adaptation. Further, intraspecific variation in phenology can result in maintenance of population diversity and lead to enhanced production in diverse stands given sufficient frequency of warming or other stress events. PMID:27258011

Latitudinal and interhemispheric variation of stratospheric effects on mesospheric ice layer trends

NASA Astrophysics Data System (ADS)

Lübken, F.-J.; Berger, U.

2011-02-01

Latitudinal and interhemispheric differences of model results on trends in mesospheric ice layers and background conditions are analyzed. The model nudges to European Centre for Medium-Range Weather Forecasts data below ˜45 km. Greenhouse gas concentrations in the mesosphere are kept constant. Temperature trends in the mesosphere mainly come from shrinking of the stratosphere and from dynamical effects. Water vapor increases at noctilucent cloud (NLC) heights and decreases above due to increased freeze drying caused by temperature trends. There is no tendency for ice clouds in the Northern Hemisphere for extending farther southward with time. Trends of NLC albedo are similar to satellite measurements, but only if a time period longer than observations is considered. Ice cloud trends get smaller if albedo thresholds relevant to satellite instruments are applied, in particular at high polar latitudes. This implies that weak and moderate NLC is favored when background conditions improve for NLC formation, whereas strong NLC benefits less. Trends of ice cloud parameters are generally smaller in the Southern Hemisphere (SH) compared to the Northern Hemisphere (NH), consistent with observations. Trends in background conditions have counteracting effects on NLC: temperature trends would suggest stronger ice increase in the SH, and water vapor trends would suggest a weaker increase. Larger trends in NLC brightness or occurrence rates are not necessarily associated with larger (more negative) temperature trends. They can also be caused by larger trends of water vapor caused by larger freeze drying, which in turn can be caused by generally lower temperatures and/or more background water. Trends of NLC brightness and occurrence rates decrease with decreasing latitude in both hemispheres. The latitudinal variation of these trends is primarily determined by induced water vapor trends. Trends in NLC altitudes are generally small. Stratospheric temperature trends vary differently with altitude in the NH and SH but add up to similar trends at mesospheric cloud heights.

Response of a Habitat-Forming Marine Plant to a Simulated Warming Event Is Delayed, Genotype Specific, and Varies with Phenology.

PubMed

Reynolds, Laura K; DuBois, Katherine; Abbott, Jessica M; Williams, Susan L; Stachowicz, John J

2016-01-01

Growing evidence shows that increasing global temperature causes population declines and latitudinal shifts in geographical distribution for plants living near their thermal limits. Yet, even populations living well within established thermal limits of a species may suffer as the frequency and intensity of warming events increase with climate change. Adaptive response to this stress at the population level depends on the presence of genetic variation in thermal tolerance in the populations in question, yet few data exist to evaluate this. In this study, we examined the immediate effects of a moderate warming event of 4.5°C lasting 5 weeks and the legacy effects after a 5 week recovery on different genotypes of the marine plant Zostera marina (eelgrass). We conducted the experiment in Bodega Bay, CA USA, where average summer water temperatures are 14-15°C, but extended warming periods of 17-18°C occur episodically. Experimental warming increased shoot production by 14% compared to controls held at ambient temperature. However, after returning temperature to ambient levels, we found strongly negative, delayed effects of warming on production: shoot production declined by 27% and total biomass decreased by 50% relative to individuals that had not been warmed. While all genotypes' production decreased in the recovery phase, genotypes that grew the most rapidly under benign thermal conditions (control) were the most susceptible to the detrimental effects of warming. This suggests a potential tradeoff in relative performance at normal vs. elevated temperatures. Modest short-term increases in water temperature have potentially prolonged negative effects within the species' thermal envelope, but genetic variation within these populations may allow for population persistence and adaptation. Further, intraspecific variation in phenology can result in maintenance of population diversity and lead to enhanced production in diverse stands given sufficient frequency of warming or other stress events.

Evidence that enforced sunlight exposure can cause hyperthermia in cattle ingesting low levels of ergot of rye (Claviceps purpurea), when air temperature and humidity conditions are only moderate.

PubMed

Bourke, C A

2003-09-01

To determine the rectal temperature response of cattle, following the oral administration of ergot of rye (Claviceps purpurea), under pen conditions of enforced sunlight compared with those of enforced shade. Hereford cross steers were divided into two groups of 18. One group was dosed once, on a Monday morning, with finely ground rye grass ergots at a rate of 180 mg/kg body weight and held in the sun for 7 h each day until Friday afternoon. The other group was not dosed but was similarly held in the sun during the same period. Their rectal temperatures were measured early morning and mid afternoon, from Monday to Friday inclusive. The process was repeated for each group, but this time they were held in the shade. The four treatment options were run concurrently by conducting the experiments over 6 weeks and using 3 animals in each treatment group, each week. The thermic response over all weeks, of the ergot treated, sunlight exposed cattle, was deemed greater than for the other groups, based on the following four parameters. The increase in rectal temperature between early morning and mid afternoon, the size of the mid afternoon rectal temperature rise, the difference between the maximum mid afternoon rectal temperature recorded by an animal in the sun compared with that recorded by the same animal in the shade, and finally the number of animals in a treatment group that recorded rectal temperatures > 40.00 degrees C. The difference in the daily increase in body temperature between the ergot treated, sun exposed cattle and the ergot treated, shaded cattle, was greater than that observed between the sun exposed and shade restricted control cattle. Nine of 18 ergot treated and sun exposed cattle developed hyperthermia; no cattle in the other three groups did. Some sunlight exposed cattle, dosed with a low amount of ergot of rye, can experience a body temperature elevation above the normal range, even under mild ambient temperature and humidity conditions. Sunlight exposure causes an increase in body temperature in normal cattle that is probably attributable to solar radiant heat. Ergot ingestion causes an increase in body temperature in shaded cattle that is probably attributable to ambient temperature and humidity effects. This response can be increased by sun exposure and this increase is attributable to solar radiant heat effects and possibly also solar radiation. A response to radiant heat is consistent with the known physiological effects of ingested ergot alkaloids, but a response to solar radiation is not.

Kinetic theory of shear thickening for a moderately dense gas-solid suspension: From discontinuous thickening to continuous thickening

NASA Astrophysics Data System (ADS)

Hayakawa, Hisao; Takada, Satoshi; Garzó, Vicente

2017-10-01

The Enskog kinetic theory for moderately dense gas-solid suspensions under simple shear flow is considered as a model to analyze the rheological properties of the system. The influence of the environmental fluid on solid particles is modeled via a viscous drag force plus a stochastic Langevin-like term. The Enskog equation is solved by means of two independent but complementary routes: (i) Grad's moment method and (ii) event-driven Langevin simulation of hard spheres. Both approaches clearly show that the flow curve (stress-strain rate relation) depends significantly on the volume fraction of the solid particles. In particular, as the density increases, there is a transition from the discontinuous shear thickening (observed in dilute gases) to the continuous shear thickening for denser systems. The comparison between theory and simulations indicates that while the theoretical predictions for the kinetic temperature agree well with simulations for densities φ ≲0.5 , the agreement for the other rheological quantities (the viscosity, the stress ratio, and the normal stress differences) is limited to more moderate densities (φ ≲0.3 ) if the inelasticity during collisions between particles is not large.

Presumed PDF Modeling of Early Flame Propagation in Moderate to Intense Turbulence Environments

NASA Technical Reports Server (NTRS)

Carmen, Christina; Feikema, Douglas A.

2003-01-01

The present paper describes the results obtained from a one-dimensional time dependent numerical technique that simulates early flame propagation in a moderate to intense turbulent environment. Attention is focused on the development of a spark-ignited, premixed, lean methane/air mixture with the unsteady spherical flame propagating in homogeneous and isotropic turbulence. A Monte-Carlo particle tracking method, based upon the method of fractional steps, is utilized to simulate the phenomena represented by a probability density function (PDF) transport equation. Gaussian distributions of fluctuating velocity and fuel concentration are prescribed. Attention is focused on three primary parameters that influence the initial flame kernel growth: the detailed ignition system characteristics, the mixture composition, and the nature of the flow field. The computational results of moderate and intense isotropic turbulence suggests that flames within the distributed reaction zone are not as vulnerable, as traditionally believed, to the adverse effects of increased turbulence intensity. It is also shown that the magnitude of the flame front thickness significantly impacts the turbulent consumption flame speed. Flame conditions studied have fuel equivalence ratio s in the range phi = 0.6 to 0.9 at standard temperature and pressure.

Kinetic theory of shear thickening for a moderately dense gas-solid suspension: From discontinuous thickening to continuous thickening.

PubMed

Hayakawa, Hisao; Takada, Satoshi; Garzó, Vicente

2017-10-01

The Enskog kinetic theory for moderately dense gas-solid suspensions under simple shear flow is considered as a model to analyze the rheological properties of the system. The influence of the environmental fluid on solid particles is modeled via a viscous drag force plus a stochastic Langevin-like term. The Enskog equation is solved by means of two independent but complementary routes: (i) Grad's moment method and (ii) event-driven Langevin simulation of hard spheres. Both approaches clearly show that the flow curve (stress-strain rate relation) depends significantly on the volume fraction of the solid particles. In particular, as the density increases, there is a transition from the discontinuous shear thickening (observed in dilute gases) to the continuous shear thickening for denser systems. The comparison between theory and simulations indicates that while the theoretical predictions for the kinetic temperature agree well with simulations for densities φ≲0.5, the agreement for the other rheological quantities (the viscosity, the stress ratio, and the normal stress differences) is limited to more moderate densities (φ≲0.3) if the inelasticity during collisions between particles is not large.

A mechanical property and stress corrosion evaluation of Custom 455 stainless steel alloy

NASA Technical Reports Server (NTRS)

Montano, J. W.

1972-01-01

The mechanical and stress corrosion properties are presented of vacuum melted Custom 455 stainless steel alloy bar (1.0-inch diameter) and sheet (0.083-inch thick) material aged at 950 F, 1000 F, and 1050 F. Low temperature mechanical properties were determined at temperatures of 80 F, 0 F, -100 F, and -200 F. For all three aging treatments, the ultimate tensile and 0.2 percent offset yield strengths increased with decreasing test temperatures while the elongation held fairly constant down to -100 F and decreased at -200 F. Reduction in Area decreased moderately with decreasing temperature for the longitudinal round (0.250-inch diameter) specimens. Notched tensile strength and charpy V-notched impact strength decreased with decreasing test temperature. For all three aging treatments, no failures were observed in the unstressed specimens or the specimens stressed to 50, 75, and 100 percent of their yield strengths for 180 days of alternate immersion testing in a 3.5 percent NaCl solution. As indicated by the results of tensile tests performed after alternate immersion testing, the mechanical properties of Custom 455 alloy were not affected by stress or exposure under the conditions of the evaluation.

Davis Fire: Fire behavior and fire effects analysis

Treesearch

LaWen T. Hollingsworth

2010-01-01

The Davis Fire presents an interesting example of fire behavior in subalpine fir, partially dead lodgepole pine with multiple age classes, and moist site Douglas-fir vegetation types. This has been summer of moderate temperatures and intermittent moisture that has kept live herbaceous and live woody moistures fairly high and dead fuel moistures at a moderate level....

A Pilot Study Examining Physical and Social Warmth: Higher (Non-Febrile) Oral Temperature Is Associated with Greater Feelings of Social Connection.

PubMed

Inagaki, Tristen K; Irwin, Michael R; Moieni, Mona; Jevtic, Ivana; Eisenberger, Naomi I

2016-01-01

An emerging literature suggests that experiences of physical warmth contribute to social warmth-the experience of feeling connected to others. Thus, thermoregulatory systems, which help maintain our relatively warm internal body temperatures, may also support feelings of social connection. However, the association between internal body temperature and feelings of connection has not been examined. Furthermore, the origins of the link between physical and social warmth, via learning during early experiences with a caregiver or via innate, co-evolved mechanisms, remain unclear. The current study examined the relationship between oral temperature and feelings of social connection as well as whether early caregiver experiences moderated this relationship. Extending the existing literature, higher oral temperature readings were associated with greater feelings of social connection. Moreover, early caregiver experiences did not moderate this association, suggesting that the physical-social warmth overlap may not be altered by early social experience. Results provide additional support for the link between experiences of physical warmth and social warmth and add to existing theories that highlight social connection as a basic need on its own.

A Pilot Study Examining Physical and Social Warmth: Higher (Non-Febrile) Oral Temperature Is Associated with Greater Feelings of Social Connection

PubMed Central

Inagaki, Tristen K.; Irwin, Michael R.; Moieni, Mona; Jevtic, Ivana; Eisenberger, Naomi I.

2016-01-01

An emerging literature suggests that experiences of physical warmth contribute to social warmth—the experience of feeling connected to others. Thus, thermoregulatory systems, which help maintain our relatively warm internal body temperatures, may also support feelings of social connection. However, the association between internal body temperature and feelings of connection has not been examined. Furthermore, the origins of the link between physical and social warmth, via learning during early experiences with a caregiver or via innate, co-evolved mechanisms, remain unclear. The current study examined the relationship between oral temperature and feelings of social connection as well as whether early caregiver experiences moderated this relationship. Extending the existing literature, higher oral temperature readings were associated with greater feelings of social connection. Moreover, early caregiver experiences did not moderate this association, suggesting that the physical-social warmth overlap may not be altered by early social experience. Results provide additional support for the link between experiences of physical warmth and social warmth and add to existing theories that highlight social connection as a basic need on its own. PMID:27257914

Metallic seal for thermal barrier coating systems

NASA Technical Reports Server (NTRS)

Miller, Robert A. (Inventor)

1990-01-01

The invention is particularly concerned with sealing thermal barrier coating systems of the type in use and being contemplated for use in diesel and other internal combustion engines. The invention also would find application in moderately high temperature regions of gas turbine engines and any other application employing a thermal barrier coating at moderate temperatures. Ni-35Cr-6Al-1Y, Ni-35Cr-6Al-1Yb, or other metallic alloy denoted as MCrAlx is applied over a zirconia-based thermal barrier overlayer. The close-out layer is glass-bead preened to densify its surface. This seals and protects the thermal barrier coating system.

Validation of Two Temperature Pill Telemetry Systems in Humans During Moderate and Strenuous Exercise

DTIC Science & Technology

1992-10-01

The concept of using a temperature sensor in a pill as a clinical thermometer Is good, but mobility of the pill makes it less suitable as a research...Human Technologies, Inc. (CorTempt m; St. Petersburg, FL). Both systems included an ingestible temperature sensor /pill, a receiver, and a data storage...telemetry pills did, and T, and T. showed a faster response to changing core temperature than did T,. The concept of using a temperature sensor in a

Room Temperature Curing Resin Systems for Graphite/Epoxy Composite Repair.

DTIC Science & Technology

1979-12-01

ROOM TEMPERATURE CURING RESIN SYSTEMS FOR GRAPHITE/EPOXY COMPOS--ETC(UI DEC 79 0 J CRABTREE N62269-79-C-G224 UNCLASSIFIE O80-46 NADC -781 1-6 NL END...Room Temperature Curing Resin Sys-U3 linal for Graphite/Epoxy Composite Repair •.Dec *79 NOR- -46h: V111IT NUM8ER(s) 4362269-79- ,722 S. PERFORMING...repair, composite repair room temperature cure resin , moderate temperature cure resins , epoxies, adhesives, vinyl eater polymers, anaerobic curing polymers

Low-temperature Ignition-delay Characteristics of Several Rocket Fuels with Mixed Acid in Modified Open-cup-type Apparatus

NASA Technical Reports Server (NTRS)

Miller, Riley O

1950-01-01

Summaries of low-temperature self-ignition data of various rocket fuels with mixed acid (nitric plus sulfuric) are presented. Several fuels are shown to have shorter ignition-delay intervals and less variation in delay intervals at moderate and sub-zero temperatures than crude N-ethylaniline (monoethylaniline),a rocket fuel in current use.

Annual cycles of soil and water temperatures at Hubbard Brook

Treesearch

C. Anthony Federer

1973-01-01

Soil temperatures in the Hubbard Brook Experimental Forest in central New Hampshire decline very slowly from December to March and are restricted from falling below OºC by insulation of snow and organic matter. Soil in the hardwood forest on a moderate south slope warms rapidly in the spring leafless period after snowmelt and reaches a maximum temperature in...

Moderate temperature sodium cells. V - Discharge reactions and rechargeability of NiS and NiS2 positive electrodes in molten NaAlCl4

NASA Technical Reports Server (NTRS)

Abraham, K. M.; Elliot, J. E.

1984-01-01

NiS2 and NiS have been characterized as high energy density rechargeable positive electrodes for moderate-temperature Na batteries of the configuration, Na(1)/beta double prime-Al2O3/NaAlCl4(1), NiSx. The batteries operate in the temperature range 170 - 190 C. Positive electrode reactions during discharge/charge cycles have been characterized. Excellent rechargeability of the batteries has been demonstrated by extended cell cycling. A Na/NiS2 cell, operating at 190 C, exceeded 600 deep discharge/charge cycles with practically no capacity deterioration. The feasibility of secondary Na/NiSx batteries with specific energies equal to or greater than 50 Wh/lb and cycle lifes exceeding 1000 deep discharge/charge cycles has been demonstrated.

Northern squawfish Ptychochelius oregonensis, O2 consumption rate: Effects of temperature and body size

USGS Publications Warehouse

Cech, Joseph J.; Castleberry, Daniel T.; Hopkins, Todd E.; Petersen, James H.

1994-01-01

Northern squawfish, Ptychocheilus oregonensis (live weight range 0.361–1.973 kg), O2consumption was measured with temperature-controlled, flow-through respirometers for >24 h. Mean standard O2 consumption rate of northern squawfish increased with acclimation temperature: 24.3, 49.1, 75.0, and 89.4 mg∙kg−0.67∙h−1 at 9, 15, 18, and 21 °C, respectively. Q10analysis showed that O2 consumption rate temperature sensitivity was greatest at the intermediate acclimation temperatures (15–18 °C, Q10 = 4.10), moderate at the lower acclimation temperatures (9–15 °C, Q10 = 3.23), and lowest at the higher acclimation temperatures (18–21 °C, Q10 = 1.80). Overall Q10 was 2.96 (9–21 °C). Body size (W, grams) and temperature (T, degrees Celcius) were related to O2 consumption (, grams per gram per day) by W−0.285∙e0.105T. Northern squawfish red to white muscle ratios significantly exceeded those of rainbow trout, Oncorhynchus mykiss, in cross sections at 50 and 75% of standard length. High metabolic rates and red to white muscle ratios argue for comparability of northern squawfish with active predators such as sympatric rainbow trout.

Demonstration of optimum fuel-to-moderator ratio in a PWR unit fuel cell

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

Feltus, M.A.; Pozsgai, C.

1992-01-01

Nuclear engineering students at The Pennsylvania State University develop scaled-down [[approx]350 MW(thermal)] pressurized water reactors (PWRs) using actual plants as references. The design criteria include maintaining the clad temperature below 2200[degree]F, fuel temperature below melting point, sufficient departure from nucleate boiling ratio (DNBR) margin, a beginning-of-life boron concentration that yields a negative moderator temperature coefficient, an adequate cycle power production (330 effective full-power days), and a batch loading scheme that is economical. The design project allows for many degrees of freedom (e.g., assembly number, pitch and height and batch enrichments) so that each student's result is unique. The iterative naturemore » of the design process is stressed in the course. The LEOPARD code is used for the unit cell depletion, critical boron, and equilibrium xenon calculations. Radial two-group diffusion equations are solved with the TWIDDLE-DEE code. The steady-state ZEBRA thermal-hydraulics program is used for calculating DNBR. The unit fuel cell pin radius and pitch (fuel-to-moerator ratio) for the scaled-down design, however, was set equal to the already optimized ratio for the reference PWR. This paper describes an honors project that shows how the optimum fuel-to-moderator ratio is found for a unit fuel cell shown in terms of neutron economics. This exercise illustrates the impact of fuel-to-moderator variations on fuel utilization factor and the effect of assuming space and energy separability.« less

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

Effect of Temperature and Moisture on the Development of Concealed Damage in Raw Almonds (Prunus dulcis).

PubMed

Rogel-Castillo, Cristian; Zuskov, David; Chan, Bronte Lee; Lee, Jihyun; Huang, Guangwei; Mitchell, Alyson E

2015-09-23

Concealed damage (CD) is a brown discoloration of nutmeat that appears only after kernels are treated with moderate heat (e.g., roasting). Identifying factors that promote CD in almonds is of significant interest to the nut industry. Herein, the effect of temperature (35 and 45 °C) and moisture (<5, 8, and 11%) on the composition of volatiles in raw almonds (Prunus dulcis var. Nonpareil) was studied using HS-SPME-GC/MS. A CIE LCh colorimetric method was developed to identify raw almonds with CD. A significant increase in CD was demonstrated in almonds exposed to moisture (8% kernel moisture content) at 45 °C as compared to 35 °C. Elevated levels of volatiles related to lipid peroxidation and amino acid degradation were observed in almonds with CD. These results suggest that postharvest moisture exposure resulting in an internal kernel moisture ≥ 8% is a key factor in the development of CD in raw almonds and that CD is accelerated by temperature.

Is Bare Band Description of Carrier Transport Appropriate in Pentacene?

NASA Astrophysics Data System (ADS)

Andersen, John D.; Giuggioli, Luca; Kenkre, V. M.

2002-03-01

Experiments on injected charges in pentacene single crystals reveal mobilities typical of inorganic semiconductors and temperature dependence (for T<430K) suggesting bandlike behavior.(J. H. Schon, C. Kloc, and B. Batlogg, Phys. Rev. Lett. 86, 3843 (2001)) Polaronic bands, particularly their narrowing with increasing temperature, were invoked(V. M. Kenkre, John D. Andersen, D.H. Dunlap, and C.B. Duke, Phys. Rev. Lett. 62, 1165 (1989)) in the related naphthalene problem.(L. B. Schein, C. B. Duke, and A.R. McGhie, Phys. Rev. Lett. 40, 197 (1978); L. B. Schein, W. Warta, and N. Karl, Chem. Phys. Lett. 100, 34 (1983)) Because the low temperature mobility values in pentacene suggest moderately large bandwidths, we address two questions. Does a bare wide (effectively infinite) band description work for pentacene for T<400K? And, is a bare finite band description compatible with those data? These questions are answered by modifications of a theory originally constructed for inorganic materials and a newly developed mobility theory.

Enhanced 99 Tc retention in glass waste form using Tc(IV)-incorporated Fe minerals

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

Um, Wooyong; Luksic, Steven A.; Wang, Guohui

Technetium (99Tc) immobilization by doping into iron oxide mineral phases may alleviate the problems with Tc volatility during vitrification of nuclear waste. Reduced Tc, Tc(IV), substitutes for Fe(III) in the crystal structure by a process of Tc reduction from Tc(VII) to Tc(IV) followed by co-precipitation of Fe oxide minerals. Two Tc-incorporated Fe minerals (Tc-goethite and Tc-magnetite/maghemite) were prepared and tested for Tc retention in glass melt samples at temperatures between 600 – 1,000 oC. After being cooled, the solid glass specimens prepared at different temperatures were analyzed for Tc oxidation state using Tc K-edge XANES. In most samples, Tc wasmore » partially oxidized from Tc(IV) to Tc(VII) as the melt temperature increased. However, Tc retention in glass melt samples prepared using Tc-incorporated Fe minerals were moderately higher than in glass prepared using KTcO4 because of limited and delayed Tc volatilization.« less