[Effects of air temperature increase and precipitation change on grain yield and quality of spring wheat in semiarid area of Northwest China].

PubMed

Wang, He-ling; Zhang, Qiang; Wang, Run-yuan; Gan, Yan-tai; Niu, Jun-yi; Zhang, Kai; Zhao, Fu-nian; Zhao, Hong

2015-01-01

In order to predict effects of climate changing on growth, quality and grain yields of spring wheat, a field experiment was conducted to investigate the effects of air temperature increases (0 °C, 1.0 °C, 2.0° C and 3.0°) and precipitation variations (decrease 20%, unchanging and increase 20%) on grain yields, quality, diseases and insect pests of spring wheat at the Dingxi Arid Meteorology and Ecological Environment Experimental Station of the Institute of Arid Meteorology of China Meteorological Administration (35°35' N ,104°37' E). The results showed that effects of precipitation variations on kernel numbers of spring wheat were not significant when temperature increased by less than 2.0° C , but was significant when temperature increased by 3.0° C. Temperature increase enhanced kernel numbers, while temperature decrease reduced kernel numbers. The negative effect of temperature on thousand-kernel mass of spring wheat increased with increasing air temperature. The sterile spikelet of spring wheat response to air temperature was quadratic under all precipitation regimes. Compared with control ( no temperature increase), the decreases of grain yield of spring wheat when air temperature increased by 1.0°C, 2.0°C and 3.0°C under each of the three precipitation conditions (decrease 20%, no changing and increase 20%) were 12.1%, 24.7% and 42.7%, 8.4%, 15.1% and 21.8%, and 9.0%, 15.5% and 22.2%, respectively. The starch content of spring wheat decreased and the protein content increased with increasing air temperature. The number of aphids increased when air temperature increased by 2.0°C , but decreased when air temperature increased by 3.0°CT. The infection rates of rust disease increased with increasing air temperature.

Correlations among body temperature, plasma progesterone, cortisol and prostaglandin F2alpha of the periparturient bitch.

PubMed

Veronesi, M C; Battocchio, M; Marinelli, L; Faustini, M; Kindahl, H; Cairoli, F

2002-06-01

The results of this study suggest that, besides the irrelevant role of body temperature measurement to predict the impending parturition in the bitch, progesterone and 15-ketodihydroprostaglandin F2alpha plasma level records could be more suitable to detect the approaching whelping in this species. More interesting was the statistically significant substantial increase in body temperature beginning 12 h after the onset of parturition. Therefore, if any significant increase in body temperature is recorded at the end of pregnancy without the beginning of the expulsion of fetuses, it could indicate problems at parturition. In this study, cortisol levels increased significantly at the time of delivery and remained high 12 h after the beginning of parturition, decreasing within 36 h after the onset of whelping. 15-ketodihydro-prostaglandin F2alpha levels increased significantly 24 h before parturition and again at the onset of whelping. Progesterone levels decreased significantly, starting 24 h before the onset of whelping and remained low after delivery.

The Effect of Insertion Technique on Temperatures for Standard and Self-Drilling External Fixation Pins.

PubMed

Manoogian, Sarah; Lee, Adam K; Widmaier, James C

2017-08-01

No studies have assessed the effects of parameters associated with insertion temperature in modern self-drilling external fixation pins. The current study assessed how varying the presence of irrigation, insertion speed, and force impacted the insertion temperatures of 2 types of standard and self-drilling external fixation half pins. Seventy tests were conducted with 10 trials for 4 conditions on self-drilling pins, and 3 conditions for standard pins. Each test used a thermocouple inside the pin to measure temperature rise during insertion. Adding irrigation to the standard pin insertion significantly lowered the maximum temperature (P <0.001). Lowering the applied force for the standard pin did not have a significant change in temperature rise. Applying irrigation during the self-drilling pin tests dropped average rise in temperature from 151.3 ± 21.6°C to 124.1 ± 15.3°C (P = 0.005). When the self-drilling pin insertion was decreased considerably from 360 to 60 rpm, the temperature decreased significantly from 151.3 ± 21.6°C to 109.6 ± 14.0°C (P <0.001). When the force applied increased significantly, the corresponding self-drilling pin temperature increase was not significant. The standard pin had lower peak temperatures than the self-drilling pin for all conditions. Moreover, slowing down the insertion speed and adding irrigation helped mitigate the temperature increase of both pin types during insertion.

Spatiotemporal trends in mean temperatures and aridity index over Rwanda

NASA Astrophysics Data System (ADS)

Muhire, I.; Ahmed, F.

2016-01-01

This study aims at quantifying the trends in mean temperatures and aridity index over Rwanda for the period of 1961-1992, based on analysis of climatic data (temperatures, precipitations, and potential evapotranspiration). The analysis of magnitude and significance of trends in temperatures and aridity index show the degree of climate change and mark the level of vulnerability to extreme events (e.g., droughts) in different areas of the country. The study reveals that mean temperatures increased in most parts of the country, with a significant increase observed in the eastern lowlands and in the southwestern parts. The highlands located in the northwest and the Congo-Nile crest showed a nonsignificant increase in mean temperatures. Aridity index increased only in March, April, October, and November, corresponding with the rainy seasons. The remaining months of the year showed a decreasing trend. At an annual resolution, the highlands and the western region showed a rise in aridity index with a decreasing pattern over the eastern lowlands and the central plateau. Generally, the highlands presented a nonsignificant increase in mean temperatures and aridity index especially during the rainy seasons. The eastern lowlands showed a significant increase in mean temperatures and decreasing trends in aridity index. Therefore, these areas are bound to experience more droughts, leading to reduced water and consequent decline in agricultural production. On the other hand, the north highlands and southwest region will continue to be more productive.

Temperature-dependent physiological and biochemical responses of the marine medaka Oryzias melastigma with consideration of both low and high thermal extremes.

PubMed

Li, Adela J; Leung, Priscilla T Y; Bao, Vivien W W; Lui, Gilbert C S; Leung, Kenneth M Y

2015-12-01

This study aimed to investigate temperature effect on physiological and biochemical responses of the marine medaka Oryzias melastigma larvae. The fish were subjected to a stepwise temperature change at a rate of 1 °C/h increasing or decreasing from 25 °C (the control) to six target temperatures (12, 13, 15, 20, 28 and 32 °C) respectively, followed by a 7-day thermal acclimation at each target temperature. The fish were fed ad libitum during the experiment. The results showed that cumulative mortalities were significantly increased at low temperatures (12 and 13 °C) and at the highest temperature (32 °C). For the survivors, their growth profile closely followed the left-skewed 'thermal performance curve'. Routine oxygen consumption rates of fish larvae were significantly elevated at 32 °C but suppressed at 13 and 15 °C (due to a high mortality, larvae from 12 °C were not examined). Levels of heat shock proteins and activities of malate dehydrogenase and lactate dehydrogenase were also measured in fish larvae exposed at 15, 25 and 32 °C. The activities of both enzymes were significantly increased at both 15 and 32 °C, where the fish larvae probably suffered from thermal discomfort and increased anaerobic components so as to compensate the mismatch of energy demand and supply at these thermal extremes. Coincidently, heat shock proteins were also up-regulated at both 15 and 32 °C, enabling cellular protection. Moreover, the critical thermal maxima and minima of fish larvae increased significantly with increasing acclimation temperature, implying that the fish could develop some degrees of thermal tolerance through temperature acclimation. Copyright © 2014 Elsevier Ltd. All rights reserved.

High mortality of Zostera marina under high temperature regimes but minor effects of the invasive macroalgae Gracilaria vermiculophylla

NASA Astrophysics Data System (ADS)

Höffle, H.; Thomsen, M. S.; Holmer, M.

2011-03-01

The present study tested for density-dependent effects of the invasive drift macroalgae Gracilaria vermiculophylla (Ohmi) Papenfuss on growth and survival of the native eelgrass, Zostera marina L., under different temperature levels. Three weeks laboratory experiments were conducted in Odense, Denmark, combining three algae densities (control, low 1.9 kg WW m -2, high 4.5 kg WW m -2) with typical Danish summer temperatures (18 °C) and elevated temperatures (21 °C and 27 °C). There was a significant effect of temperature on shoot survival with on average 68% mortality in the high temperature treatment but almost no mortality at the two lower temperatures. The higher mortality was probably caused by high sulphide levels in the sediment pore water (0.6 mmol l -1 at 18 °C compared to 3.7 mmol l -1 at 27 °C). Above-ground growth of the surviving shoots was also significantly affected by temperature, with leaf elongation rates being negatively affected, while the leaf plastochrone interval increased. Relative growth rate was significantly higher at 21 °C than at 18 °C or 27 °C, whereas rhizome elongation was significantly lowest at 27 °C. Elemental sulphur content in the plant tissues increased significantly with temperature and was up to 34 times higher (S 0 in rhizomes) at 27 °C compared to the lower temperatures. In contrast to the temperature effects, cover by G. vermiculophylla did not cause significant effects on any seagrass responses. However, there was a (non-significant) negative effect of algal cover at the highest temperature, where the seagrass is already stressed. The latter results suggest that more studies should test for interaction effects between temperature and other anthropogenic stressors given that temperature is predicted to increase in the near future.

Long-term trends in daily temperature extremes in Iraq

NASA Astrophysics Data System (ADS)

Salman, Saleem A.; Shahid, Shamsuddin; Ismail, Tarmizi; Chung, Eun-Sung; Al-Abadi, Alaa M.

2017-12-01

The existence of long-term persistence (LTP) in hydro-climatic time series can lead to considerable change in significance of trends. Therefore, past findings of climatic trend studies that did not consider LTP became a disputable issue. A study has been conducted to assess the trends in temperature and temperature extremes in Iraq in recent years (1965-2015) using both ordinary Mann-Kendal (MK) test; and the modified Mann-Kendall (m-MK) test, which can differentiate the multi-decadal oscillatory variations from secular trends. Trends in annual and seasonal minimum and maximum temperatures, diurnal temperature range (DTR), and 14 temperature-related extremes were assessed. MK test detected the significant increases in minimum and maximum temperature at all stations, where m-MK test detected at 86% and 80% of all stations, respectively. The temperature in Iraq is increasing 2 to 7 times faster than global temperature rise. The minimum temperature is increasing more (0.48-1.17 °C/decade) than maximum temperature (0.25-1.01 °C/decade). Temperature rise is higher in northern Iraq and in summer. The hot extremes particularly warm nights are increasing all over Iraq at a rate of 2.92-10.69 days/decade, respectively. On the other hand, numbers of cold days are decreasing at some stations at a rate of - 2.65 to - 8.40 days/decade. The use of m-MK test along with MK test confirms the significant increase in temperature and some of the temperature extremes in Iraq. This study suggests that trends in many temperature extremes in the region estimated in previous studies using MK test may be due to natural variability of climate, which empathizes the need for validation of the trends by considering LTP in time series.

Interactive effects of climate change and eutrophication on the dinoflagellate-bearing benthic foraminifer Marginopora vertebralis

NASA Astrophysics Data System (ADS)

Uthicke, S.; Vogel, N.; Doyle, J.; Schmidt, C.; Humphrey, C.

2012-06-01

Elevated sea surface temperatures caused by global climate change and increased nutrient concentrations resulting from land runoff both are stressors for calcifying coral reef organisms. Here, we test the hypothesis that increased temperature leads to bleaching in dinoflagellate-bearing foraminifera similar to corals and that increased nutrients through runoff can exaggerate stress on the holobiont. In an experiment manipulating temperatures alone, we have shown that mortality of Marginopora vertebralis increased with temperatures. Most individuals died after 7 days at 34°C, ~5°C above current summer maxima. Survival at 37 days was >98% at 28°C. After 7 days of exposure to 31 or 32°C, photosynthesis of the endosymbionts was compromised, as indicated by several photophysiological parameters (effective quantum yield and apparent photosynthetic rate). In a flow-though experiment manipulating both temperature (three levels, 26, 29 and 31°C) and nitrate concentrations (3 levels, ~0.5, 1.0 and 1.4 μmol l-1 NO3 -), elevated temperature had a significant negative effect on most parameters measured. At 31°C, most photopigments (measured by UPLC) in the foraminifera were significantly reduced. The only pigment that increased was the photoprotective diatoxanthin. Several other parameters measured (maximum and effective quantum yield, O2 production in light, organic carbon contents) also significantly decreased with temperature. Optode-based respirometry demonstrated that the presence of symbionts at elevated temperatures represents a net carbon loss for the host. Growth rates of M. vertebralis and mortality at the end of the experiment were significantly affected by both temperature increase and nitrate addition. We conclude that these foraminifera bleach in a similar fashion to corals and that global sea surface temperature change and nitrate increases are stressors for these protists. Furthermore, this provides support for the hypothesis that management of local stressors elevates resilience of coral reefs to global stressors.

Effect of Temperature on Mechanical Properties of Nanoclay Reinforced Polymeric Nanocomposites. Part 1. Experimental Results

DTIC Science & Technology

2012-04-23

Temperature and nanoclay reinforcement affect the Poisson ?s ratio also, but this effect is less significant. In general, as the temperature increases...the Poisson ?s ratio also increases. However, an increase in nanoclay reinforcement generally reduces the Poisson ?s ratio . It is also noted that the...nanoclay reinforcement generally reduces the Poisson’s ratio . It is also noted that the type of resin used may have a significant effect on the

Trend analysis of long-term temperature time series in the Greater Toronto Area (GTA)

NASA Astrophysics Data System (ADS)

Mohsin, Tanzina; Gough, William A.

2010-08-01

As the majority of the world’s population is living in urban environments, there is growing interest in studying local urban climates. In this paper, for the first time, the long-term trends (31-162 years) of temperature change have been analyzed for the Greater Toronto Area (GTA). Annual and seasonal time series for a number of urban, suburban, and rural weather stations are considered. Non-parametric statistical techniques such as Mann-Kendall test and Theil-Sen slope estimation are used primarily for the assessing of the significance and detection of trends, and the sequential Mann test is used to detect any abrupt climate change. Statistically significant trends for annual mean and minimum temperatures are detected for almost all stations in the GTA. Winter is found to be the most coherent season contributing substantially to the increase in annual minimum temperature. The analyses of the abrupt changes in temperature suggest that the beginning of the increasing trend in Toronto started after the 1920s and then continued to increase to the 1960s. For all stations, there is a significant increase of annual and seasonal (particularly winter) temperatures after the 1980s. In terms of the linkage between urbanization and spatiotemporal thermal patterns, significant linear trends in annual mean and minimum temperature are detected for the period of 1878-1978 for the urban station, Toronto, while for the rural counterparts, the trends are not significant. Also, for all stations in the GTA that are situated in all directions except south of Toronto, substantial temperature change is detected for the periods of 1970-2000 and 1989-2000. It is concluded that the urbanization in the GTA has significantly contributed to the increase of the annual mean temperatures during the past three decades. In addition to urbanization, the influence of local climate, topography, and larger scale warming are incorporated in the analysis of the trends.

Temperature affects transport of polysaccharides and proteins in articular cartilage explants.

PubMed

Moeini, Mohammad; Lee, Kwan-Bong; Quinn, Thomas M

2012-07-26

Solute transport phenomena mediate many aspects of the physiology and contrast agent-based clinical imaging of articular cartilage. Temperatures up to 10°C below standard body temperature (37°C) are common in articulating joints during normal activities and clinically (e.g. cold treatment of injuries). Therefore it is of interest to characterize the effects of temperature changes on solute transport parameters in cartilage. A range of fluorescent solutes including fluorescein isothiocyanate, 4 and 40kDa dextrans, myoglobin, insulin and chondroitin sulfate were prepared and used in assays of solute effective partition coefficient and effective diffusivity in bovine intermediate zone articular cartilage explants maintained at 10, 22 or 37°C. Trends for increasing partition coefficient with increasing temperature were evident for all solutes except chondroitin sulfate, with significant changes between 22 and 37°C for 4kDa dextran, insulin and myoglobin. Diffusivities of most solutes tested also tended to increase with increasing temperature, with significant changes between 10 and 22°C for FITC, 40kDa dextran and myoglobin. Oddly, insulin diffusivity decreased significantly as temperature increased from 22 to 37°C while chondroitin sulfate diffusivity exhibited no clear temperature dependence. These results highlight solute-specific temperature dependences of transport phenomena which may depend upon molecular weight, chemical structure, molecular conformation, and solute-matrix and solute-solute interactions. The articular cartilage explants themselves exhibited small but significant changes in water and glycosaminoglycan contents during experiments, underscoring the importance of solute-matrix interactions. Solute transport parameters in cartilage and their temperature dependences are therefore not easily predicted, and case-by-case experimental determination may be essential. Copyright © 2012 Elsevier Ltd. All rights reserved.

Change in mean temperature as a predictor of extreme temperature change in the Asia-Pacific region

NASA Astrophysics Data System (ADS)

Griffiths, G. M.; Chambers, L. E.; Haylock, M. R.; Manton, M. J.; Nicholls, N.; Baek, H.-J.; Choi, Y.; della-Marta, P. M.; Gosai, A.; Iga, N.; Lata, R.; Laurent, V.; Maitrepierre, L.; Nakamigawa, H.; Ouprasitwong, N.; Solofa, D.; Tahani, L.; Thuy, D. T.; Tibig, L.; Trewin, B.; Vediapan, K.; Zhai, P.

2005-08-01

Trends (1961-2003) in daily maximum and minimum temperatures, extremes and variance were found to be spatially coherent across the Asia-Pacific region. The majority of stations exhibited significant trends: increases in mean maximum and mean minimum temperature, decreases in cold nights and cool days, and increases in warm nights. No station showed a significant increase in cold days or cold nights, but a few sites showed significant decreases in hot days and warm nights. Significant decreases were observed in both maximum and minimum temperature standard deviation in China, Korea and some stations in Japan (probably reflecting urbanization effects), but also for some Thailand and coastal Australian sites. The South Pacific convergence zone (SPCZ) region between Fiji and the Solomon Islands showed a significant increase in maximum temperature variability.Correlations between mean temperature and the frequency of extreme temperatures were strongest in the tropical Pacific Ocean from French Polynesia to Papua New Guinea, Malaysia, the Philippines, Thailand and southern Japan. Correlations were weaker at continental or higher latitude locations, which may partly reflect urbanization.For non-urban stations, the dominant distribution change for both maximum and minimum temperature involved a change in the mean, impacting on one or both extremes, with no change in standard deviation. This occurred from French Polynesia to Papua New Guinea (except for maximum temperature changes near the SPCZ), in Malaysia, the Philippines, and several outlying Japanese islands. For urbanized stations the dominant change was a change in the mean and variance, impacting on one or both extremes. This result was particularly evident for minimum temperature.The results presented here, for non-urban tropical and maritime locations in the Asia-Pacific region, support the hypothesis that changes in mean temperature may be used to predict changes in extreme temperatures. At urbanized or higher latitude locations, changes in variance should be incorporated.

Climate Change and Simulation of Cardiovascular Disease Mortality: A Case Study of Mashhad, Iran.

PubMed

Baaghideh, Mohammad; Mayvaneh, Fatemeh

2017-03-01

Weather and climate play a significant role in human health. We are accustomed to affects the weather conditions. By increasing or decreasing the environment temperature or change of seasons, some diseases become prevalent or remove. This study investigated the role of temperature in cardiovascular disease mortality of city of Mashhad in the current decade and its simulation in the future decades under conditions of climate change. Cardiovascular disease mortality data and the daily temperatures data were used during (2004-2013) period. First, the correlation between cardiovascular disease mortality and maximum and minimum temperatures were calculated then by using General Circulation Model, Emissions Scenarios, and temperature data were extracted for the next five decades and finally, mortality was simulated. There is a strong positive association between maximum temperature and mortality (r= 0.83, P -value<0.01), also observed a negative and weak but significant association between minimum temperatures and mortality. The results obtained from simulation show increased temperature in the next decades in Mashhad and a 1 °C increase in maximum temperature is associated with a 4.27% (95%CI: 0.91, 7.00) increase in Cardiovascular disease mortality. By increasing temperature and the number of hot days the cardiovascular disease mortality increases and these increases will be intensified in the future decades. Therefore, necessary preventive measures are required to mitigate temperature effects with greater attention to vulnerable group.

Climate change and the impact of extreme temperatures on aviation

NASA Astrophysics Data System (ADS)

Coffel, E.; Horton, R.

2014-12-01

Weather is the most significant factor affecting aircraft operations, accounting for 70-80% of passenger delays and costing airlines hundreds of millions of dollars per year in lost revenue. Temperature and airport elevation significantly influence the maximum allowable takeoff weight of an aircraft by changing the surface air density and thus the lift produced at a given speed. For a given runway length, airport elevation, and aircraft type there is a temperature threshold above which the airplane cannot take off at its maximum weight and thus must be weight restricted. The number of summer days necessitating weight restriction has increased since 1980 along with the observed increase in surface temperature. Climate change is projected to increase mean temperatures at all airports and significantly increase the frequency and severity of extreme heat events at some. These changes will negatively affect aircraft performance, leading to increased weight restrictions especially at airports with short runways and little room to expand. For a Boeing 737-800 aircraft, we find that the number of weight restriction days between May and September will increase by 50-100% at four major airports in the United States by 2050-2070 under the RCP8.5 high emissions scenario. These performance reductions may have a significant economic effect on the airline industry, leading to lower profits and higher passenger fares. Increased weight restrictions have previously been identified as potential impacts of climate change, but this study is the first to quantify the effect of higher temperatures on commercial aviation.

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

Jinlong, Lv, E-mail: ljlbuaa@126.com; State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084; Tongxiang, Liang, E-mail: ljltsinghua@126.com

The nanocrystalline pure nickels with different grain orientations were fabricated by direct current electrodeposition process. The grain size slightly decreased with the increasing of electrodeposition solution temperature. However, grain orientation was affected significantly. Comparing with samples obtained at 50 °C and 80 °C, sample obtained at 20 °C had the strongest (111) orientation plane which increased electrochemical corrosion resistance of this sample. At the same time, the lowest (111) orientation plane deteriorated electrochemical corrosion resistance of sample obtained at 50 °C. - Graphical abstract: The increased electrodeposition temperature promoted slightly grain refinement. The grain orientation was affected significantly by electrodepositionmore » solution temperature. The (111) orientation plane of sample increased significantly corrosion resistance. Display Omitted.« less

EFFECT OF WEARING AN N95 FILTERING FACEPIECE RESPIRATOR ON SUPEROMEDIAL ORBITAL INFRARED INDIRECT BRAIN TEMPERATURE MEASUREMENTS

PubMed Central

DiLeo, Travis; Roberge, Raymond J.; Kim, Jung-Hyun

2016-01-01

Purpose To determine any effect of wearing a filtering facepiece respirator on brain temperature. Methods Subjects (n=18) wore a filtering facepiece respirator (FFR) for 1h at rest while undergoing infrared thermography measurements of the superomedial periobital region of the eye, a non-invasive indirect method of brain temperature measurements we termed the superomedial orbital infrared indirect brain temperature (SOIIBT) measurement. Temperature of the facial skin covered by the FFR, infrared temperature measurements of the tympanic membrane and superficial temporal artery region were concurrently measured, and subjective impressions of thermal comfort obtained simultaneously. Results The temperature of the skin under the FFR and subjective impressions of thermal discomfort both increased significantly. The mean tympanic membrane temperature did not increase, and the superficial temporal artery region temperature decreased significantly. The SOIIBT values did not change significantly, but subjects who switched from nasal to oronasal breathing during the study (n=5) experienced a slight increase in the SOIIBT measurements. Conclusions Wearing a FFR for 1h at rest does not have a significant effect on brain temperatures, as evaluated by the SOIIBT measurements, but a change in the route of breathing may impact these measurements. These findings suggest that subjective impressions of thermal discomfort from wearing a FFR under the study conditions are more likely the result of local dermal sensations rather than brain warming. PMID:26759336

Physiological energetics of the thick shell mussel Mytilus coruscus exposed to seawater acidification and thermal stress.

PubMed

Wang, Youji; Li, Lisha; Hu, Menghong; Lu, Weiqun

2015-05-01

Anthropogenic CO₂ emissions have caused seawater temperature elevation and ocean acidification. In view of both phenomena are occurring simultaneously, their combined effects on marine species must be experimentally evaluated. The purpose of this study was to estimate the combined effects of seawater acidification and temperature increase on the energy budget of the thick shell mussel Mytilus coruscus. Juvenile mussels were exposed to six combined treatments with three pH levels (8.1, 7.7 and 7.3)×two temperatures (25 °C and 30 °C) for 14 d. We found that clearance rates (CRs), food absorption efficiencies (AEs), respiration rates (RRs), ammonium excretion rates (ER), scope for growth (SFG) and O:N ratios were significantly reduced by elevated temperature sometimes during the whole experiments. Low pH showed significant negative effects on RR and ER, and significantly increased O:N ratios, but showed almost no effects on CR, AE and SFG of M. coruscus. Nevertheless, their interactive effects were observed in RR, ER and O:N ratios. PCA revealed positive relationships among most physiological indicators, especially between SFG and CR under normal temperatures compared to high temperatures. PCA also showed that the high RR was closely correlated to an increasing ER with increasing pH levels. These results suggest that physiological energetics of juvenile M. coruscus are able to acclimate to CO2 acidification with a little physiological effect, but not increased temperatures. Therefore, the negative effects of a temperature increase could potentially impact the ecophysiological responses of M. coruscus and have significant ecological consequences, mainly in those habitats where this species is dominant in terms of abundance and biomass. Copyright © 2015 Elsevier B.V. All rights reserved.

Magnetic Properties of Fe-49Co-2V Alloy and Pure Fe at Room and Elevated Temperatures

NASA Technical Reports Server (NTRS)

De Groh, Henry C., III; Geng, Steven M.; Niedra, Janis M.; Hofer, Richard R.

2018-01-01

The National Aeronautics and Space Administration (NASA) has a need for soft magnetic materials for fission power and ion propulsion systems. In this work the magnetic properties of the soft magnetic materials Hiperco 50 (Fe-49wt%Cr-2V) and CMI-C (commercially pure magnetic iron) were examined at various temperatures up to 600 C. Toroidal Hiperco 50 samples were made from stacks of 0.35 mm thick sheet, toroidal CMI-C specimens were machined out of solid bar stock, and both were heat treated prior to testing. The magnetic properties of a Hiperco 50 sample were measured at various temperatures up to 600 C and then again after returning to room temperature; the magnetic properties of CMI-C were tested at temperatures up to 400 C. For Hiperco 50 coercivity decreased as temperature increased, and remained low upon returning to room temperature; maximum permeability improved (increased) with increasing temperature and was dramatically improved upon returning to room temperature; remanence was not significantly affected by temperature; flux density at H = 0.1 kA/m increased slightly with increasing temperature, and was about 20% higher upon returning to room temperature; flux density at H = 0.5 kA/m was insensitive to temperature. It appears that the properties of Hiperco 50 improved with increasing temperature due to grain growth. There was no significant magnetic property difference between annealed and aged CMI-C iron material; permeability tended to decrease with increasing temperature; the approximate decline in the permeability at 400 C compared to room temperature was 30%; saturation flux density, B(sub S), was approximately equal for all temperatures below 400 C; B(sub S) was lower at 400 C.

A pharmacologic study on the mechanism of action of Kakkon-to: body temperature elevation and phagocytic activation of macrophages in dogs.

PubMed

Muraoka, Kenichi; Yoshida, Satoshi; Hasegawa, Kazumasa; Nakanishi, Nobuo; Fukuzawa, Isao; Tomita, Akio; Cyong, Jong Chol

2004-10-01

The phagocytic activity of macrophages as a novel approach to scientific elucidation of the effects of Chinese medicines was studied through administration of a kampo preparation, by measuring the rise in body temperature, which is thought to stimulate innate defensive functions of organisms and enhance the immune systems. Using dogs as experimental models, a rise in body temperature following administration of Kakkon-to was observed, and the average number and average rate of phagocytosis of macrophages in blood using latex micro-particles was investigated. The body temperature of the treated animals significantly increased 30 minutes after administration (p<0.01), and remained elevated for more than 5 hours. A comparison of body temperatures before and after administration showed significant increases over controls from 1 to 11 hours, p<0.01; and at 12 hours, p<0.05 after administration. The average number and the average rate of phagocytosis were significantly increased 1 (p<0.05) and 2 (p<0.01) hours after administration. The mean number of phagocytized cells significantly increased (p<0.05) at 1 hour after administration compared with that before administration, and the mean phagocytic rate also increased significantly (p<0.01) 2 hours after administration. Increases (p<0.01) in both the rate of phagocytosis and the number of cells phagocytized were found at every measurement point from 2 to 24 hours after administration. Significant increases (p<0.01) were also observed in both the rate of phagocytosis and the number of cells phagocytized 3 hours after administration, when compared with the control group. This paper demonstrates that ingestion of Kakkon-to not only increases the body temperature but also enhances the phagocytic activity of macrophages, an in vivo defense mechanism, suggesting that Kakkon-to contributes to the suppression of multiplication of common cold viruses and influenza viruses, which consequently results in improvement of various symptoms during infection with common cold viruses.

Des-acyl ghrelin prevents heatstroke-like symptoms in rats exposed to high temperature and high humidity.

PubMed

Inoue, Yoshiyuki; Hayashi, Yujiro; Kangawa, Kenji; Suzuki, Yoshihiro; Murakami, Noboru; Nakahara, Keiko

2016-02-26

We have shown previously that des-acyl ghrelin decreases body temperature in rats through activation of the parasympathetic nervous system. Here we investigated whether des-acyl ghrelin ameliorates heatstroke in rats exposed to high temperature. Peripheral administration of des-acyl ghrelin significantly attenuated hyperthermia induced by exposure to high-temperature (35°C) together with high humidity (70-80%). Although biochemical analysis revealed that exposure to high temperature significantly increased hematocrit and the serum levels of aspartate amino transferase (AST), alanine transaminase (ALT), blood urea nitrogen (BUN), creatinine and electrolytes (Na(+), K(+), Cl(-)), most of these heatstroke-associated reactions were significantly reduced by treatment with des-acyl ghrelin. The level of des-acyl ghrelin in plasma was also found to be significantly increased under high-temperature conditions. These results suggest that des-acyl ghrelin could be useful for preventing heatstroke under high temperature condition. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Evolution of surface sensible heat over the Tibetan Plateau under the recent global warming hiatus

NASA Astrophysics Data System (ADS)

Zhu, Lihua; Huang, Gang; Fan, Guangzhou; Qu, Xia; Zhao, Guijie; Hua, Wei

2017-10-01

Based on regular surface meteorological observations and NCEP/DOE reanalysis data, this study investigates the evolution of surface sensible heat (SH) over the central and eastern Tibetan Plateau (CE-TP) under the recent global warming hiatus. The results reveal that the SH over the CE-TP presents a recovery since the slowdown of the global warming. The restored surface wind speed together with increased difference in ground-air temperature contribute to the recovery in SH. During the global warming hiatus, the persistent weakening wind speed is alleviated due to the variation of the meridional temperature gradient. Meanwhile, the ground surface temperature and the difference in ground-air temperature show a significant increasing trend in that period caused by the increased total cloud amount, especially at night. At nighttime, the increased total cloud cover reduces the surface effective radiation via a strengthening of atmospheric counter radiation and subsequently brings about a clear upward trend in ground surface temperature and the difference in ground-air temperature. Cloud-radiation feedback plays a significant role in the evolution of the surface temperature and even SH during the global warming hiatus. Consequently, besides the surface wind speed, the difference in ground-air temperature becomes another significant factor for the variation in SH since the slowdown of global warming, particularly at night.

Effects of Seawater Salinity and Temperature on Growth and Pigment Contents in Hypnea cervicornis J. Agardh (Gigartinales, Rhodophyta)

PubMed Central

Ding, Lanping; Ma, Yuanyuan; Huang, Bingxin; Chen, Shanwen

2013-01-01

This study simulated outdoor environmental living conditions and observed the growth rates and changes of several photosynthetic pigments (Chl a, Car, PE, and PC) in Hypnea cervicornis J. Agardh (Gigartinales, Rhodophyta) by setting up different ranges of salinity (25, 30, 35, 40, 45, and 50) and temperature (15, 20, 25, and 30°C). At conditions of culture, the results are as follows. (1) Changes in salinity and temperature have significant effects on the growth of H. cervicornis. The growth rates first increase then decrease as the temperature increases, while growth tends to decline as salinity increases. The optimum salinity and temperature conditions for growth are 25 and 25°C, respectively. (2) Salinity and temperature have significant or extremely significant effects on photosynthetic pigments (Chl a, Car, PE, and PC) in H. cervicornis. The results of this study are advantageous to ensure propagation and economic development of this species in the southern sea area of China. PMID:24350276

A three-stage hybrid model for regionalization, trends and sensitivity analyses of temperature anomalies in China from 1966 to 2015

NASA Astrophysics Data System (ADS)

Wu, Feifei; Yang, XiaoHua; Shen, Zhenyao

2018-06-01

Temperature anomalies have received increasing attention due to their potentially severe impacts on ecosystems, economy and human health. To facilitate objective regionalization and examine regional temperature anomalies, a three-stage hybrid model with stages of regionalization, trends and sensitivity analyses was developed. Annual mean and extreme temperatures were analyzed using the daily data collected from 537 stations in China from 1966 to 2015, including the annual mean, minimum and maximum temperatures (Tm, TNm and TXm) as well as the extreme minimum and maximum temperatures (TNe and TXe). The results showed the following: (1) subregions with coherent temperature changes were identified using the rotated empirical orthogonal function analysis and K-means clustering algorithm. The numbers of subregions were 6, 7, 8, 9 and 8 for Tm, TNm, TXm, TNe and TXe, respectively. (2) Significant increases in temperature were observed in most regions of China from 1966 to 2015, although warming slowed down over the last decade. This warming primarily featured a remarkable increase in its minimum temperature. For Tm and TNm, 95% of the stations showed a significant upward trend at the 99% confidence level. TNe increased the fastest, at a rate of 0.56 °C/decade, whereas 21% of the stations in TXe showed a downward trend. (3) The mean temperatures (Tm, TNm and TXm) in the high-latitude regions increased more quickly than those in the low-latitude regions. The maximum temperature increased significantly at high elevations, whereas the minimum temperature increased greatly at middle-low elevations. The most pronounced warming occurred in eastern China in TNe and northwestern China in TXe, with mean elevations of 51 m and 2098 m, respectively. A cooling trend in TXe was observed at the northwestern end of China. The warming rate in TNe varied the most among the subregions (0.63 °C/decade).

Human population growth and temperature increase along with the increase in urbanisation, motor vehicle numbers and green area amount in the sample of Erzurum city, Turkey.

PubMed

Yilmaz, Sevgi; Toy, Süleyman; Demircioglu Yildiz, Nalan; Yilmaz, Hasan

2009-01-01

In the study, main purpose was to determine the effect of population growth along with the increase in urbanisation, motor vehicle use and green area amount on the temperature values using a 55-year data set in Erzurum, which is hardly industrialised, and one of the coldest cities with highest elevation in Turkey. Although the semi-decadal increases, means of which are 0.1 degrees C for mean, minimum and maximum temperatures, are not clear enough to make a strong comment even in the lights of figures or tables, it was found as the result of the statistical analysis that population growth and increases in the number of vehicles, the number of buildings and the green area amount in the city have no significant effect on mean temperatures. However, the relationships between population growth and maximum temperature; and the number of vehicles and minimum temperature were found to be statistically significant.

Innovative trend analysis of annual and seasonal air temperature and rainfall in the Yangtze River Basin, China during 1960-2015

NASA Astrophysics Data System (ADS)

Cui, Lifang; Wang, Lunche; Lai, Zhongping; Tian, Qing; Liu, Wen; Li, Jun

2017-11-01

The variation characteristics of air temperature and precipitation in the Yangtze River Basin (YRB), China during 1960-2015 were analysed using a linear regression (LR) analysis, a Mann-Kendall (MK) test with Sen's slope estimator and Sen's innovative trend analysis (ITA). The results showed that the annual maximum, minimum and mean temperature significantly increased at the rate of 0.15°C/10yr, 0.23°C/10yr and 0.19°C/10yr, respectively, over the whole study area during 1960-2015. The warming magnitudes for the above variables during 1980-2015 were much higher than those during 1960-2015:0.38°C/10yr, 0.35°C/10yr and 0.36°C/10yr, respectively. The seasonal maximum, minimum and mean temperature significantly increased in the spring, autumn and winter seasons during 1960-2015. Although the summer temperatures also increased at some extent, only the minimum temperature showed a significant increasing trend. Meanwhile, the highest rate of increase of seasonal mean temperature occurred in winter (0.24°C/10yr) during 1960-2015 and spring (0.50°C/10yr) during 1980-2015, which indicated that the significant warming trend for the whole YRB could be attributed to the remarkable temperature increases in winter and spring months. However, both the annual and seasonal warming magnitudes showed large regional differences, and a higher warming rate was detected in the eastern YRB and the western source region of the Yangtze River on the Qinghai-Tibetan Plateau (QTP). Additionally, annual precipitation increased by approximately 12.02 mm/10yr during 1960-2015 but decreased at the rate of 19.63 mm/10yr during 1980-2015. There were decreasing trends for precipitation in all four seasons since 1980 in the YRB, and a significant increasing trend was only detected in summer since 1960 (12.37 mm/10yr). Overall, a warming-wetting trend was detected in the south-eastern and north-western YRB, while there was a warming-drying trend in middle regions.

Geo-spatial analysis of temporal trends of temperature and its extremes over India using daily gridded (1°×1°) temperature data of 1969-2005

NASA Astrophysics Data System (ADS)

Chakraborty, Abhishek; Seshasai, M. V. R.; Rao, S. V. C. Kameswara; Dadhwal, V. K.

2017-10-01

Daily gridded (1°×1°) temperature data (1969-2005) were used to detect spatial patterns of temporal trends of maximum and minimum temperature (monthly and seasonal), growing degree days (GDDs) over the crop-growing season ( kharif, rabi, and zaid) and annual frequencies of temperature extremes over India. The direction and magnitude of trends, at each grid level, were estimated using the Mann-Kendall statistics ( α = 0.05) and further assessed at the homogeneous temperature regions using a field significance test ( α=0.05). General warming trends were observed over India with considerable variations in direction and magnitude over space and time. The spatial extent and the magnitude of the increasing trends of minimum temperature (0.02-0.04 °C year-1) were found to be higher than that of maximum temperature (0.01-0.02 °C year-1) during winter and pre-monsoon seasons. Significant negative trends of minimum temperature were found over eastern India during the monsoon months. Such trends were also observed for the maximum temperature over northern and eastern parts, particularly in the winter month of January. The general warming patterns also changed the thermal environment of the crop-growing season causing significant increase in GDDs during kharif and rabi seasons across India. The warming climate has also caused significant increase in occurrences of hot extremes such as hot days and hot nights, and significant decrease in cold extremes such as cold days and cold nights.

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.

Trends and periodicity of daily temperature and precipitation extremes during 1960-2013 in Hunan Province, central south China

NASA Astrophysics Data System (ADS)

Chen, Ajiao; He, Xinguang; Guan, Huade; Cai, Yi

2018-04-01

In this study, the trends and periodicity in climate extremes are examined in Hunan Province over the period 1960-2013 on the basis of 27 extreme climate indices calculated from daily temperature and precipitation records at 89 meteorological stations. The results show that in the whole province, temperature extremes exhibit a warming trend with more than 50% stations being statistically significant for 7 out of 16 temperature indices, and the nighttime temperature increases faster than the daytime temperature at the annual scale. The changes in most extreme temperature indices show strongly coherent spatial patterns. Moreover, the change rates of almost all temperature indices in north Hunan are greater than those of other regions. However, the statistically significant changes in indices of extreme precipitation are observed at fewer stations than in extreme temperature indices, forming less spatially coherent patterns. Positive trends in indices of extreme precipitation show that the amount and intensity of extreme precipitation events are generally increasing in both annual and seasonal scales, whereas the significant downward trend in consecutive wet days indicates that the precipitation becomes more even over the study period. Analysis of changes in probability distributions of extreme indices for 1960-1986 and 1987-2013 also demonstrates a remarkable shift toward warmer condition and increasing tendency in the amount and intensity of extreme precipitation during the past decades. The variations in extreme climate indices exhibit inconstant frequencies in the wavelet power spectrum. Among the 16 temperature indices, 2 of them show significant 1-year periodic oscillation and 7 of them exhibit significant 4-year cycle during some certain periods. However, significant periodic oscillations can be found in all of the precipitation indices. Wet-day precipitation and three absolute precipitation indices show significant 1-year cycle and other seven provide significant power at the 4-year period, which are mainly found during 1970-1980 and after 1992.

Combined effects of temperature and avermectins on life history and stress response of the western flower thrips, Frankliniella occidentalis.

PubMed

Li, Hong-Bo; Zheng, Yu-Tao; Sun, Dan-Dan; Wang, Jian-Jun; Du, Yu-Zhou

2014-01-01

Temperature and pesticide are two important factors that affect survival, reproduction and other physiological processes of insects. To determine interactions of elevated temperature and avermectins treatment on the western flower thrips, Frankliniella occidentalis, newly emerged adults were exposed to combinations of three temperatures (21, 26 and 33 °C) and two avermectins concentrations (0, 45 ppm), and survival rate, reproduction, longevity, antioxidant enzymes activities and heat shock proteins (hsps) induction were analyzed. The results showed that the survival, longevity and reproduction of F. occidentalis decreased with increased temperature and avermectins treatment. While elevated temperature and avermectins treatment significantly decreased activity of SOD, activities of POD and GST significantly increased after exposure to elevated temperature, avermectins or their combination. Elevated temperature had no effect on activity of CAT, but it was obviously improved by the combination of temperature and avermectins treatment. Expression analysis of hsps showed that four heat shock proteins (hsp90, hsc702, hsp60 and hop) were up-regulated by the induction of elevated temperature with small fold changes. After treatment with avermectins, expression levels of hsp90, hsc701, hsc702 and hop were significantly up-regulated with increased temperature and higher than those of their respective control at higher temperature. Surprisingly, expression level of hps60 was down-regulated with increased temperature, but the expression level at 21 or 26 °C remained higher than that of control. Overall, our studies suggest that elevated temperature enhance toxicity of avermectins and their combination induced acute oxidative damage to F. occidentalis. Therefore, consideration of temperature in evaluating avermectins toxicity is necessary to make accurate prediction of its effect on F. occidentalis and other insects. Copyright © 2014 Elsevier Inc. All rights reserved.

Thermoregulatory responses of rats exposed to 9. 3-GHz radio-frequency radiation

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

Frei, M.R.; Jauchem, J.R.; Heinmets, F.

1987-10-15

Ketamine-anesthetized Sprague-Dawley rats were exposed in H orientation to far-field 9.3-GHz continuous-wave (CW) and pulsed (2 microseconds 500 pps) radiofrequency radiation (RFR) at average power densities of 30 and 60 mW/sq. cm (whole-body average specific absorption rates of 9.3 and 18.6 W/kg, respectively). Irradiation was conducted to cyclicly increase colonic temperature from 38.5 to 39.5 C. Colonic, tympanic, and subcutaneous temperatures, ECG, blood pressure, and respiratory rate were continuously recorded during experimentation. At both power densities, the subcutaneous and tympanic temperature increases significantly exceeded the colonic temperature increase. At both exposure levels, heart rate increased significantly during irradiation and returnedmore » to baseline when exposure was discontinued. Blood pressure and respiratory rate did not significantly change during irradiation. There were no significant differences between the effects of CW and pulsed RFR exposure. The levels of subcutaneous heating and heart rate change were greater, and the times required to achieve and to recover from a 1 C colonic temperature increase were longer than in previous studies conducted at 2.8 GHz. Results of these studies indicate that the carrier frequency used during irradiation markedly affects the pattern of heat distribution and the physiological responses of RF-irradiated animals.« less

Secular Trend of Surface Temperature at an Elevated Observatory in the Pyrenees.

NASA Astrophysics Data System (ADS)

Bücher, A.; Dessens, J.

1991-08-01

Surface temperature was measured at the Pic du Midi de Bigorre, 2862 m MSL, from the foundation of the Observatory in 1878 until the closing of the meteorological station in 1984. After testing the homogeneity of the series with the annual mean temperatures in western Europe and in southwestern France, the period 1882-1970 was retained for trend analysis.The mean annual temperature increased 0.83°C during the 89-yr period. This increase is the sum of a very significant increase in the daily minimum temperature (+ 2.11°C) and a decrease in the maximum temperature ( 0.45°C). In consequence, the most dramatic change in the temperature regime was the difference between maximum and minimum; this decreased from 8.05°C in 1882 to 5.49°C in 1970. A mean increase is observed in all seasons, but, as for western Europe, it is stronger in spring and fall than in winter and summer.Analysis of cloudiness data for the same period shows a 15% increase in annual mean cloudiness and also significant year-to-year correlations between cloudiness and the maximum and minimum temperature. In consequence, the change in the temperature regime observed at the Pic du Midi since the end of last century is most probably the result of a climatic change involving an increase in cloud cover and, maybe, an increasing greenhouse effect.

Field orientation effects during 5. 6-GHz radiofrequency irradiation of rats

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

Frei, M.R.; Jauchem, J.R.; Price, D.L.

1990-12-01

Ketamine-anesthetized Sprague-Dawley rats were exposed in E and H orientations (long axis parallel to electric and magnetic fields, respectively) to far-field 5.6-GHz continuous-wave radio-frequency radiation (RFR). Power densities were used that resulted in equivalent whole-body average specific absorption rates of 14 W/kg in both orientations (90 mW/cm2 for E and 66 mW/cm2 for H). Irradiation was conducted to increase colonic temperature by 1 degree C (from 38.5 to 39.5 degrees C). During experimentation, arterial blood pressure and respiratory rate and colonic, tympanic, left and right subcutaneous (sides toward and away from RFR source), and tail temperatures were continuously recorded. Resultsmore » showed no significant difference in the times required to cause a 1 degree C increase or to recover to the initial temperature when irradiation was stopped. Significant differences between E- and H-orientation exposure were seen in the patterns of localized heating. The tail and left subcutaneous temperature increases were significantly greater during E-orientation exposure, the tympanic site showed no difference, and the right subcutaneous temperature increase was significantly greater during H-orientation exposure. Under both exposure conditions, heart rate and mean arterial blood pressure significantly increased during irradiation; however, there were no significant differences between E and H orientation responses. These findings at 5.6 GHz are in contrast to the significant cardiovascular response differences between E- and H-orientation exposure noted during a previous study of irradiation at 2.45 GHz.« less

The association of extreme temperatures and the incidence of tuberculosis in Japan

NASA Astrophysics Data System (ADS)

Onozuka, Daisuke; Hagihara, Akihito

2015-08-01

Seasonal variation in the incidence of tuberculosis (TB) has been widely assumed. However, few studies have investigated the association between extreme temperatures and the incidence of TB. We collected data on cases of TB and mean temperature in Fukuoka, Japan for 2008-2012 and used time-series analyses to assess the possible relationship of extreme temperatures with TB incident cases, adjusting for seasonal and interannual variation. Our analysis revealed that the occurrence of extreme heat temperature events resulted in a significant increase in the number of TB cases (relative risk (RR) 1.20, 95 % confidence interval (CI) 1.01-1.43). We also found that the occurrence of extreme cold temperature events resulted in a significant increase in the number of TB cases (RR 1.23, 95 % CI 1.05-1.45). Sex and age did not modify the effect of either heat or cold extremes. Our study provides quantitative evidence that the number of TB cases increased significantly with extreme heat and cold temperatures. The results may help public health officials predict extreme temperature-related TB incidence and prepare for the implementation of preventive public health interventions.

Effect of Sowing Quantity on Soil Temperature and Yield of Winter Wheat under Straw Strip Mulching in Arid Region of Northwest China

NASA Astrophysics Data System (ADS)

Lan, Xuemei; Chai, Yuwei; Li, Rui; Li, Bowen; Cheng, Hongbo; Chang, Lei; Chai, Shouxi

2018-01-01

In order to explore the characteristics and relationship between soil temperature and yield of winter wheat, under different sowing quantities conditions of straw mulching conventional drilling in Northwest China, this study took Lantian 26 as material, under the whole corn mulching conventional drilling in Changhe town and Pingxiang town, setting up 3 different seeding quantities of 270 kg/ha (SSMC1), 324 kg/ha (SSMC2) and 405 kg/ha (SSMC3), to study the difference of soil temperature during the growth period of winter wheat and its correlation with yield components. Results showed: the average soil temperature of 0∼25cm in two ecological zones in the whole growth period have a significant change with the increase of sowing quantities; too much seeding had a sharp drop in soil temperature; the highest temperature of SSMC in Changhe town was the middle quantity of SSMC 2; the highest temperature of SSMC in Pingxiang town was the lowest sowing quantity of SSMC1. Diurnal variation of soil temperature at all growth stages showed: with the increase of SSMC, in the morning it increased with the increase of soil depth, noon and evening reducing with the depth of the soil. The average soil temperature of SSMC2 was higher than that of in all the two ecological zones in the whole growth period of SSMC.The maximum day temperature difference of each treatment was at noon. With the increase of SSMC, the yield increase varied with two ecological zones. SSMC of the local conventional sowing quantity of 270kg/ha SSMC1 yield was the highest in Changhe Town. SSMC of the middle sowing quantity SSMC2 of 324kg/ha yield was the highest in Pingxiang town. The difference of grain number per spike was the main cause of yield difference among these 3 treatments. Correlation analysis showed: the correlation among the yield and yield components, growth index and soil temperature varied with different ecological zones; thousand kernel weight and grain number per ear (.964** and.891**) had a very significant positive correlation with the yields in Changhe Town, but thousand kernel weight and grain number per ear (.708* and.718*) had a significant positive correlation with yield in Pingxiang Town. There was a significant positive correlation between harvest index and 10cm soil temperature (.763*). But in Pingxiang Town grain number per ear and 15cm soil temperature showed a significant positive correlation (.671*); 15cm soil temperature and the average temperature of 0∼25cm soil layer in the whole growth period (-.687* and -.698*) had a significant negative correlation with the number of panicles per unit area; there was a very significant negative correlation between plant height and average temperature of 0∼25cm in the whole growth period (-.906**). Thus, the changes of soil temperature under SSMC different sowing quantity have indirect effect on the yield of winter wheat.

Does temperature of charcoal creation affect subsequent mineralization of soil carbon and nitrogen?

NASA Astrophysics Data System (ADS)

Pelletier-Bergeron, S.; Bradley, R.; Munson, A. D.

2012-04-01

Forest fire is the most common form of natural disturbance of boreal forest ecosystems and has primordial influence on successional processes. This may be due in part to the pre-disturbance vegetation development stage and species composition, but these successional pathways could also vary with differences in fire behavior and consequently in fire intensity, defined as the energy released during various phases of a fire. Fire intensity may also affect soil C and N cycling by affecting the quality of the charcoal that is produced. For example, the porosity of coal tends to increase with increasing temperature at which it is produced Higher porosity would logically increase the surface area to which dissolved soil molecules, such as tannins and other phenolics, may be adsorbed. We report on a microcosm study in which mineral and organic soils were jointly incubated for eight weeks with a full factorial array of treatments that included the addition of Kalmia tannins, protein, and wood charcoal produced at five different temperatures. A fourth experimental factor comprised the physical arrangement of the material (stratified vs. mixed), designed to simulate the effect of soil scarification after fire and salvage harvest. We examined the effects of these treatments on soil C and N mineralisation and soil microbial biomass. The furnace temperature at which the charcoal was produced had a significant effect on its physico-chemical properties; increasing furnace temperatures corresponded to a significant increase in % C (P<0.001), and a significant decrease in %O (P<0.001) and %H (P<0.001). Temperature also had significant impacts on microporosity (surface area and volume). Temperature of production had no effect (P=0.1355) on soil microbial biomass. We observed a linear decreasing trend (P<0.001) in qCO2 with increasing temperature of production, which was mainly reflected in a decline in basal respiration. Finally, we found a significant interaction (P=0.010) between temperature of charcoal production x soil mixing in controlling post incubation NH4+ concentrations. We discuss the results in relation to potential implications for changing fire regime and C and N cycles.

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

PubMed

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

2017-03-01

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

Climate Change and Its Impact on the Eco-Environment of the Three-Rivers Headwater Region on the Tibetan Plateau, China.

PubMed

Jiang, Chong; Zhang, Linbo

2015-09-25

This study analyzes the impact of climate change on the eco-environment of the Three-Rivers Headwater Region (TRHR), Tibetan Plateau, China. Temperature and precipitation experienced sharp increases in this region during the past 57 years. A dramatic increase in winter temperatures contributed to a rise in average annual temperatures. Moreover, annual runoff in the Lancang (LRB) and Yangtze (YARB) river basins showed an increasing trend, compared to a slight decrease in the Yellow River Basin (YRB). Runoff is predominantly influenced by rainfall, which is controlled by several monsoon systems. The water temperature in the YRB and YARB increased significantly from 1958 to 2007 (p < 0.001), driven by air temperature changes. Additionally, owing to warming and wetting trends in the TRHR, the net primary productivity (NPP) and normalized difference vegetation index (NDVI) showed significant increasing trends during the past half-century. Furthermore, although an increase in water erosion due to rainfall erosivity was observed, wind speeds declined significantly, causing a decline in wind erosion, as well as the frequency and duration of sandstorms. A clear regional warming trend caused an obvious increasing trend in glacier runoff, with a maximum value observed in the 2000s.

Climate Change and Its Impact on the Eco-Environment of the Three-Rivers Headwater Region on the Tibetan Plateau, China

PubMed Central

Jiang, Chong; Zhang, Linbo

2015-01-01

This study analyzes the impact of climate change on the eco-environment of the Three-Rivers Headwater Region (TRHR), Tibetan Plateau, China. Temperature and precipitation experienced sharp increases in this region during the past 57 years. A dramatic increase in winter temperatures contributed to a rise in average annual temperatures. Moreover, annual runoff in the Lancang (LRB) and Yangtze (YARB) river basins showed an increasing trend, compared to a slight decrease in the Yellow River Basin (YRB). Runoff is predominantly influenced by rainfall, which is controlled by several monsoon systems. The water temperature in the YRB and YARB increased significantly from 1958 to 2007 (p < 0.001), driven by air temperature changes. Additionally, owing to warming and wetting trends in the TRHR, the net primary productivity (NPP) and normalized difference vegetation index (NDVI) showed significant increasing trends during the past half-century. Furthermore, although an increase in water erosion due to rainfall erosivity was observed, wind speeds declined significantly, causing a decline in wind erosion, as well as the frequency and duration of sandstorms. A clear regional warming trend caused an obvious increasing trend in glacier runoff, with a maximum value observed in the 2000s. PMID:26404333

Influence of elevated carbon dioxide and temperature on belowground carbon allocation and enzyme activities in tropical flooded soil planted with rice.

PubMed

Bhattacharyya, P; Roy, K S; Neogi, S; Manna, M C; Adhya, T K; Rao, K S; Nayak, A K

2013-10-01

Changes in the soil labile carbon fractions and soil biochemical properties to elevated carbon dioxide (CO2) and temperature reflect the changes in the functional capacity of soil ecosystems. The belowground root system and root-derived carbon products are the key factors for the rhizospheric carbon dynamics under elevated CO2 condition. However, the relationship between interactive effects of elevated CO2 and temperature on belowground soil carbon accrual is not very clear. To address this issue, a field experiment was laid out to study the changes of carbon allocation in tropical rice soil (Aeric Endoaquept) under elevated CO2 and elevated CO2 + elevated temperature conditions in open top chambers (OTCs). There were significant increase of root biomass by 39 and 44 % under elevated CO2 and elevated CO2 + temperature compared to ambient condition, respectively. A significant increase (55 %) of total organic carbon in the root exudates under elevated CO2 + temperature was noticed. Carbon dioxide enrichment associated with elevated temperature significantly increased soil labile carbon, microbial biomass carbon, and activities of carbon-transforming enzyme like β-glucosidase. Highly significant correlations were noticed among the different soil enzymes and soil labile carbon fractions.

Effects of meal size, meal type, and body temperature on the specific dynamic action of anurans.

PubMed

Secor, Stephen M; Wooten, Jessica A; Cox, Christian L

2007-02-01

Specific dynamic action (SDA), the increase in metabolism stemming from meal digestion and assimilation, varies as a function of meal size, meal type, and body temperature. To test predictions of these three determinants of SDA, we quantified and compared the SDA responses of nine species of anurans, Bombina orientalis, Bufo cognatus, Ceratophrys ornata, Dyscophus antongilli, Hyla cinerea, Kassina maculata, Kassina senegalensis, Pyxicephalus adspersus, and Rana catesbeiana subjected to meal size, meal type, and body temperature treatments. Over a three to seven-fold increase in meal size, anurans experienced predicted increases in postprandial rates of oxygen consumption (VO(2)) the duration of elevated VO(2) and SDA. Meal type had a significant influence on the SDA response, as the digestion and assimilation of hard-bodied, chitinous crickets, mealworms, and superworms required 76% more energy than the digestion and assimilation of soft-bodied earthworms, waxworms, and neonate rodents. Body temperature largely effected the shape of the postprandial metabolic profile; peak VO(2) increased and the duration of the response decreased with an increase in body temperature. Variation in body temperature did not significantly alter SDA for four species, whereas both H. cinerea and R. catesbeiana experienced significant increases in SDA with body temperature. For 13 or 15 species of anurans ranging in mass from 2.4 to 270 g, SMR, postprandial peak VO(2) and SDA scaled with body mass (log-log) with mass exponents of 0.79, 0.93, and 1.05, respectively.

Effects of preheated combustion air on laminar coflow diffusion flames under normal and microgravity conditions

NASA Astrophysics Data System (ADS)

Ghaderi Yeganeh, Mohammad

Global energy consumption has been increasing around the world, owing to the rapid growth of industrialization and improvements in the standard of living. As a result, more carbon dioxide and nitrogen oxide are being released into the environment. Therefore, techniques for achieving combustion at reduced carbon dioxide and nitric oxide emission levels have drawn increased attention. Combustion with a highly preheated air and low-oxygen concentration has been shown to provide significant energy savings, reduce pollution and equipment size, and uniform thermal characteristics within the combustion chamber. However, the fundamental understanding of this technique is limited. The motivation of the present study is to identify the effects of preheated combustion air on laminar coflow diffusion flames. Combustion characteristics of laminar coflow diffusion flames are evaluated for the effects of preheated combustion air temperature under normal and low-gravity conditions. Experimental measurements are conducted using direct flame photography, particle image velocimetry (PIV) and optical emission spectroscopy diagnostics. Laminar coflow diffusion flames are examined under four experimental conditions: normal-temperature/normal-gravity (case I), preheated-temperature/normal gravity (case II), normal-temperature/low-gravity (case III), and preheated-temperature/low-gravity (case IV). Comparisons between these four cases yield significant insights. In our studies, increasing the combustion air temperature by 400 K (from 300 K to 700 K), causes a 37.1% reduction in the flame length and about a 25% increase in peak flame temperature. The results also show that a 400 K increase in the preheated air temperature increases CH concentration of the flame by about 83.3% (CH is a marker for the rate of chemical reaction), and also increases the C2 concentration by about 60% (C2 is a marker for the soot precursor). It can therefore be concluded that preheating the combustion air increases the energy release intensity, flame temperature, C2 concentration, and, presumably, NOx production. Our work is the first to consider preheated temperature/low-gravity combustion. The results of our experiments reveal new insights. Where as increasing the temperature of the combustion air reduces the laminar flame width under normal gravity, we find that, in a low-gravity environment, increasing the combustion air temperature causes a significant increase in the flame width.

Effect of test temperature and strain rate on the tensile properties of high-strength, high-conductivity copper alloys

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

Zinkle, S.J.; Eatherly, W.S.

1997-04-01

The unirradiated tensile properties of wrought GlidCop AL25 (ITER grade zero, IGO) solutionized and aged CuCrZr, and cold-worked and aged and solutionized and aged Hycon 3HP{trademark} CuNiBe have been measured over the temperature range of 20-500{degrees}C at strain rates between 4 x 10{sup {minus}4} s{sup {minus}1} and 0.06 s{sup {minus}1}. The measured room temperature electrical conductivity ranged from 64 to 90% IACS for the different alloys. All of the alloys were relatively insensitive to strain rate at room temperature, but the strain rate sensitivity of GlidCop Al25 increased significantly with increasing temperature. The CuNiBe alloys exhibited the best combination ofmore » high strength and high conductivity at room temperature. The strength of CuNiBe decreased slowly with increasing temperature. However, the ductility of CuNiBe decreased rapidly with increasing temperature due to localized deformation near grain boundaries, making these alloy heats unsuitable for typical structural applications above 300{degrees}C. The strength and uniform elongation of GlidCop Al25 decreased significantly with increasing temperature at a strain rate of 1 x 10{sup {minus}3} s{sup {minus}1}, whereas the total elongation was independent of test temperature. The strength and ductility of CuCrZr decreased slowly with increasing temperature.« less

Temperature sensitivity of methanogenesis in a thermokarst lake sediment core

NASA Astrophysics Data System (ADS)

Heslop, J. K.; Walter Anthony, K. M.; Grosse, G.; Anthony, P.; Bondurant, A.

2016-12-01

Little is known about temperature sensitivity of permafrost organic carbon (OC) mineralization over time scales of years to centuries following thaw. Due to their formation and thaw histories, taliks (thaw bulbs) beneath thermokarst lakes provide a unique natural laboratory from which to examine how permafrost thawed in saturated anaerobic conditions responds to changes in temperature following long periods of time since thaw. We anaerobically incubated samples from a 590 cm thermokarst lake sediment core near Fairbanks, Alaska at four temperatures (0, 3, 10, and 25 ºC) bracketing observed talik temperatures. We show that since initial thaw 400 yr BP CH4 production shifts from being most sensitive to at lower (0-3 ºC; Q10-EC=1.15E7) temperatures to being most sensitive at higher (10-25 ºC; Q10-EC=67) temperatures. Frozen sediments collected from beneath the talik, thawed at the commencement of the incubation, had significant (p ≤ 0.05) increases in CH4 production rates at lower temperatures but did not show significant CH4 production rate increases at higher temperatures (10-25 ºC). We hypothesize the thawing of sediments removed a major barrier to C mineralization, leading to rapid initial permafrost C mineralization and preferential mineralization of the most biolabile OC compounds. In contrast, sediments which had been thawed beneath the lake for longer periods of time did not experience statistically significant increases in CH4 production at lower temperatures (0-10 ºC), but had high temperature sensitivities at higher temperatures (10-25 ºC). We believe these rate increases are due to warmer temperatures in the experimental incubations crossing activation energy thresholds, allowing previously recalcitrant fractions of OC to be utilized, and/or the presence of different microbial communities adapted to thawed sediments. Recently-deposited sediments at shallow depths in the lake core experienced increases in CH4 production across all incubation temperatures (Q10-ST=4.4).

Temperature and geographic attribution of change in the Taraxacum mongolicum growing season from 1990 to 2009 in eastern China's temperate zone.

PubMed

Chen, Xiaoqiu; Tian, Youhua; Xu, Lin

2015-10-01

Using leaf unfolding and leaf coloration data of a widely distributed herbaceous species, Taraxacum mongolicum, we detected linear trend and temperature response of the growing season at 52 stations from 1990 to 2009. Across the research region, the mean growing season beginning date marginal significantly advanced at a rate of -2.1 days per decade, while the mean growing season end date was significantly delayed at a rate of 3.1 days per decade. The mean growing season length was significantly prolonged at a rate of 5.1 days per decade. Over the 52 stations, linear trends of the beginning date correlate negatively with linear trends of spring temperature, whereas linear trends of the end date and length correlate positively with linear trends of autumn temperature and annual mean temperature. Moreover, the growing season linear trends are also closely related to the growing season responses to temperature and geographic coordinates plus elevation. Regarding growing season responses to temperature, a 1 °C increase in regional mean spring temperature results in an advancement of 2.1 days in regional mean growing season beginning date, and a 1 °C increase in regional mean autumn temperature causes a delay of 2.3 days in regional mean growing season end date. A 1 °C increase in regional annual mean temperature induces an extension of 8.7 days in regional mean growing season length. Over the 52 stations, response of the beginning date to spring temperature depends mainly on local annual mean temperature and geographic coordinates plus elevation. Namely, a 1 °C increase in spring temperature induces a larger advancement of the beginning date at warmer locations with lower latitudes and further west longitudes than at colder locations with higher latitudes and further east longitudes, while a 1 °C increase in spring temperature causes a larger advancement of the beginning date at higher than at lower elevations.

Temperature and geographic attribution of change in the Taraxacum mongolicum growing season from 1990 to 2009 in eastern China's temperate zone

NASA Astrophysics Data System (ADS)

Chen, Xiaoqiu; Tian, Youhua; Xu, Lin

2015-10-01

Using leaf unfolding and leaf coloration data of a widely distributed herbaceous species, Taraxacum mongolicum, we detected linear trend and temperature response of the growing season at 52 stations from 1990 to 2009. Across the research region, the mean growing season beginning date marginal significantly advanced at a rate of -2.1 days per decade, while the mean growing season end date was significantly delayed at a rate of 3.1 days per decade. The mean growing season length was significantly prolonged at a rate of 5.1 days per decade. Over the 52 stations, linear trends of the beginning date correlate negatively with linear trends of spring temperature, whereas linear trends of the end date and length correlate positively with linear trends of autumn temperature and annual mean temperature. Moreover, the growing season linear trends are also closely related to the growing season responses to temperature and geographic coordinates plus elevation. Regarding growing season responses to temperature, a 1 °C increase in regional mean spring temperature results in an advancement of 2.1 days in regional mean growing season beginning date, and a 1 °C increase in regional mean autumn temperature causes a delay of 2.3 days in regional mean growing season end date. A 1 °C increase in regional annual mean temperature induces an extension of 8.7 days in regional mean growing season length. Over the 52 stations, response of the beginning date to spring temperature depends mainly on local annual mean temperature and geographic coordinates plus elevation. Namely, a 1 °C increase in spring temperature induces a larger advancement of the beginning date at warmer locations with lower latitudes and further west longitudes than at colder locations with higher latitudes and further east longitudes, while a 1 °C increase in spring temperature causes a larger advancement of the beginning date at higher than at lower elevations.

Seasonality, Rather than Nutrient Addition or Vegetation Types, Influenced Short-Term Temperature Sensitivity of Soil Organic Carbon Decomposition

PubMed Central

He, Feng-Peng; Wang, Wei

2016-01-01

The response of microbial respiration from soil organic carbon (SOC) decomposition to environmental changes plays a key role in predicting future trends of atmospheric CO2 concentration. However, it remains uncertain whether there is a universal trend in the response of microbial respiration to increased temperature and nutrient addition among different vegetation types. In this study, soils were sampled in spring, summer, autumn and winter from five dominant vegetation types, including pine, larch and birch forest, shrubland, and grassland, in the Saihanba area of northern China. Soil samples from each season were incubated at 1, 10, and 20°C for 5 to 7 days. Nitrogen (N; 0.035 mM as NH4NO3) and phosphorus (P; 0.03 mM as P2O5) were added to soil samples, and the responses of soil microbial respiration to increased temperature and nutrient addition were determined. We found a universal trend that soil microbial respiration increased with increased temperature regardless of sampling season or vegetation type. The temperature sensitivity (indicated by Q10, the increase in respiration rate with a 10°C increase in temperature) of microbial respiration was higher in spring and autumn than in summer and winter, irrespective of vegetation type. The Q10 was significantly positively correlated with microbial biomass and the fungal: bacterial ratio. Microbial respiration (or Q10) did not significantly respond to N or P addition. Our results suggest that short-term nutrient input might not change the SOC decomposition rate or its temperature sensitivity, whereas increased temperature might significantly enhance SOC decomposition in spring and autumn, compared with winter and summer. PMID:27070782

Effects of Surface Roughness, Oxidation, and Temperature on the Emissivity of Reactor Pressure Vessel Alloys

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

King, J. L.; Jo, H.; Tirawat, R.

Thermal radiation will be an important mode of heat transfer in future high-temperature reactors and in off-normal high-temperature scenarios in present reactors. In this work, spectral directional emissivities of two reactor pressure vessel (RPV) candidate materials were measured at room temperature after exposure to high-temperature air. In the case of SA508 steel, significant increases in emissivity were observed due to oxidation. In the case of Grade 91 steel, only very small increases were observed under the tested conditions. Effects of roughness were also investigated. To study the effects of roughening, unexposed samples of SA508 and Grade 91 steel were roughenedmore » via one of either grinding or shot-peening before being measured. Significant increases were observed only in samples having roughness exceeding the roughness expected of RPV surfaces. While the emissivity increases for SA508 from oxidation were indeed significant, the measured emissivity coefficients were below that of values commonly used in heat transfer models. Based on the observed experimental data, recommendations for emissivity inputs for heat transfer simulations are provided.« less

Desiccation and thermal tolerance of eggs and the coexistence of competing mosquitoes

PubMed Central

Juliano, Steven A.; O’Meara, George F.; Morrill, Jeneen R.; Cutwa, Michele M.

2009-01-01

We tested the hypothesis that differences in temperature and desiccation tolerances of eggs of the container-dwelling mosquitoes Aedes albopictus and Aedes aegypti influence whether invading A. albopictus coexist with or exclude A. aegypti in Florida. In the laboratory, egg mortality through 30 days for A. albopictus was strongly temperature and humidity dependent, with low humidity and high temperature producing greatest mortality. In contrast, mortality through 30 days and through 60 days for A. aegypti was very low and independent of temperature and humidity. Mortality through 90 days for A. aegypti showed significant effects of both temperature and humidity. In the field, the proportion of vases occupied by A. albopictus was significantly lower at four of six sites at the start of the wet season (after a dry period) versus well into the wet season (after containers had held water for weeks). The proportion of vases occupied by A. aegypti was independent of when during the wet season vases were sampled. These results imply that dry periods cause disproportionately greater mortality of A. albopictus eggs compared to A. aegypti eggs. Container occupancy at tire and cemetery sites was significantly related to two principal components derived from longterm average climate data. Occupancy of containers by A. albopictus was greatest at cool sites with little or no dry season, and decreased significantly with increasing mean temperature and increasing number of dry months. In contrast, occupancy of containers by A. aegypti was lowest at cool sites with little or no dry season, and increased significantly with increasing mean temperature and increasing dry season length, and decreased significantly with total precipitation and number of wet months. We suggest that local coexistence of these species is possible because warm, dry climates favor A. aegypti and alleviate effects of competition from A. albopictus via differential mortality of A. albopictus eggs. PMID:20871747

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

Weinbeck, S.

Meteorological data collected at SRS since the mid-1960’s have been analyzed for trends in minimum and maximum temperature, heating and cooling degree days, precipitation and relative humidity. The trends in meteorological data collected have been relatively small compared to the interannual variability that is observed. The observed increases, while small, appear to be real (statistically significant). Overnight low temperatures (3.1°F) have increased over twice as fast as the increases in daytime highs (1.4°F). Similarly, there are statistically significant increases in the number of cooling degree days as well. There has been a similar decrease in the number of HDD andmore » freezing days, consistent with the overall increase in overnight low temperatures.« less

Thermal Stress

DTIC Science & Technology

2011-01-01

can have a significant impact on normal physiological functioning if precipitous increases in core temperature are not adequately controlled with...anterior hypothalamusIntroduction Thermal stress can have a significant impact on normal physiological functioning if precipitous increases in core...fat and skin). The regulation of a relatively constant internal temperature is critical for normal physiological functioning of tissues and cells, as

Validation of time and temperature values as critical limits for Salmonella and background flora growth during the production of fresh ground and boneless pork products.

PubMed

Mann, J E; Smith, L; Brashears, M M

2004-07-01

To provide pork processors with valuable data to validate the critical limits set for temperature during pork fabrication and grinding, a study was conducted to determine the growth of Salmonella serotypes and background flora at various temperatures. Growth of Salmonella Typhimurium and Salmonella Enteritidis and of background flora was monitored in ground pork and boneless pork chops held at various temperatures to determine growth patterns. Case-ready modified atmosphere packaged ground pork and fresh whole pork loins were obtained locally. Boneless chops and ground pork were inoculated with a cocktail mixture of streptomycin-resistant Salmonella to facilitate recovery in the presence of background flora. Samples were held at 4.4, 7.2C, and 10 degrees C and at room temperature (22.2 to 23.3 degrees C) to mimic typical processing and holding temperatures observed in pork processing environments. Salmonella counts were determined at regular intervals over 12 and 72 h for both room and refrigeration temperatures. No significant growth of Salmonella (P < 0.05) was observed in boneless pork chops held at refrigeration temperatures. However, Salmonella in boneless pork chops held at room temperature had grown significantly by 8 h. Salmonella grew at faster rates in ground pork. Significant growth was observed at 6, 24. and 72 h when samples were held at room temperature, 10 degrees C, and 7.2 degrees C, respectively. No significant growth was observed at 4.4 degrees C. Background flora in ground pork samples increased significantly after 10 h at room temperature and after 12 h for samples held at 10 and 7.2 degrees C. Background flora in samples held at refrigeration temperatures did not increase until 72 h. Background flora in the boneless chops increased significantly after 6 h at room temperature and after 24 h when held at 10 and 4.4 degrees C. These results illustrate that meat processors can utilize a variety of time and temperature combinations as critical limits to minimize Salmonella growth during production and storage of raw pork products.

Costs of living for juvenile Chinook salmon (Oncorhynchus tshawytscha) in an increasingly warming and invaded world

USGS Publications Warehouse

Kuehne, Lauren M.; Olden, Julian D.; Duda, Jeffrey J.

2012-01-01

Rapid environmental change in freshwater ecosystems has created a need to understand the interactive effects of multiple stressors, with temperature and invasive predators identified as key threats to imperiled fish species. We tested the separate and interactive effects of water temperature and predation by non-native smallmouth bass (Micropterus dolomieu) on the lethal (mortality) and sublethal (behavior, physiology, and growth) effects for juvenile Chinook salmon (Oncorhynchus tshawytscha) in seminatural stream channel experiments. Over 48 h trials, there was no difference in direct predation with warmer temperatures, but significant interactive effects on sublethal responses of juvenile salmon. Warmer temperatures resulted in significantly stronger and more variable antipredator responses (surface shoaling and swimming activity), while physiological indicators (plasma glucose, plasma cortisol) suggested suppression of physiological mechanisms in response to the combined stressors. These patterns corresponded with additive negative growth in predation, temperature, and combined treatments. Our results suggest that chronic increases in temperature may not increase direct predation over short periods, but can result in significant sublethal costs with negative implications for long-term development, disease resistance, and subsequent size-selective mortality of Pacific salmon.

[Effects of urban river width on the temperature and humidity of nearby green belts in summer].

PubMed

Ji, Peng; Zhu, Chun-Yang; Li, Shu-Hua

2012-03-01

As an important part of urban ecosystem, urban river plays a vital role in improving urban ecological environment. By the methods of small scale quantitative measurement, this paper analyzed the effects of seven urban rivers with different widths along the Third to Fifth Ring in Beijing on the air temperature and relative humidity of nearby green belts. The results showed that urban river width was the main factor affecting the temperature and humidity of nearby green belts. When the river had a width of 8 m, it had no effects in decreasing temperature but definite effects in increasing humidity; when the river width was 14-33 m, obvious effects were observed in decreasing temperature and increasing humidity; when the river had a width larger than 40 m, the effects in decreasing temperature and increasing humidity were significant and tended to be stable. There existed significant differences in the temperature and humidity between the green belts near the seven rivers and the corresponding controls. The critical width of urban river for the obvious effects in decreasing temperature and increasing humidity was 44 m. The regression equation of the temperature (x) and humidity (y) for the seven green belts nearby the urban rivers in summer was y = 173.191-3.247x, with the relative humidity increased by 1.0% when the air temperature decreased by about 0.3 degrees C.

Thermal effects of diagnostic ultrasound in an anthropomorphic skull model.

PubMed

Vyskocil, E; Pfaffenberger, S; Kollmann, C; Gleiss, A; Nawratil, G; Kastl, S; Unger, E; Aumayr, K; Schuhfried, O; Huber, K; Wojta, J; Gottsauner-Wolf, M

2012-12-01

Exposure to diagnostic ultrasound (US) can significantly heat biological tissue although conventional routine examinations are regarded as safe. The risk of unwanted thermal effects increases with a high absorption coefficient and extended insonation time. Certain applications of transcranial diagnostic US (TC-US) require prolonged exposure. An anthropomorphic skull model (ASM) was developed to evaluate thermal effects induced by TC-US of different modalities. The objective was to determine whether prolonged continuous TC-US application results in potentially harmful temperature increases. The ASM consists of a human skull with tissue mimicking material and exhibits acoustic and anatomical characteristics of the human skull and brain. Experiments are performed with a diagnostic US device testing four different US modalities: Duplex PW (pulsed wave) Doppler, PW Doppler, color flow Doppler and B-mode. Temperature changes are recorded during 180 minutes of insonation. All measurements revealed significant temperature increases during insonation independent of the US modality. The maximum temperature elevation of + 5.25° C (p < 0.001) was observed on the surface of the skull exposed to duplex PW Doppler. At the bone-brain border a maximum temperature increae of + 2.01 °C (p < 0.001) was noted. Temperature increases within the brain were < 1.23 °C (p = 0.001). The highest values were registered using the duplex PW Doppler modality. TC-US induces significant local heating effects in an ASM. An application duration that extends routine clinical periods causes potentially harmful heating especially in tissue close to bone. TC-US elevates the temperature in the brain mimicking tissue but is not capable of producing harmful temperature increases during routine examinations. However, the risk of thermal injury in brain tissue increases significantly after an exposure time of > 2 hours. © Georg Thieme Verlag KG Stuttgart · New York.

Laboratory Investigation on Physical and Mechanical Properties of Granite After Heating and Water-Cooling Treatment

NASA Astrophysics Data System (ADS)

Zhang, Fan; Zhao, Jianjian; Hu, Dawei; Skoczylas, Frederic; Shao, Jianfu

2018-03-01

High-temperature treatment may cause changes in physical and mechanical properties of rocks. Temperature changing rate (heating, cooling and both of them) plays an important role in those changes. Thermal conductivity tests, ultrasonic pulse velocity tests, gas permeability tests and triaxial compression tests are performed on granite samples after a heating and rapid cooling treatment in order to characterize the changes in physical and mechanical properties. Seven levels of temperature (from 25 to 900 °C) are used. It is found that the physical and mechanical properties of granite are significantly deteriorated by the thermal treatment. The porosity shows a significant increase from 1.19% at the initial state to 6.13% for samples heated to 900 °C. The increase in porosity is mainly due to three factors: (1) a large number of microcracks caused by the rapid cooling rate; (2) the mineral transformation of granite through high-temperature heating and water-cooling process; (3) the rapid cooling process causes the mineral particles to weaken. As the temperature of treatment increases, the thermal conductivity and P-wave velocity decrease while the gas permeability increases. Below 200 °C, the elastic modulus and cohesion increase with temperature increasing. Between 200 and 500 °C, the elastic modulus and cohesion have no obvious change with temperature. Beyond 500 °C, as the temperature increases, the elastic modulus and cohesion obviously decrease and the decreasing rate becomes slower with the increase in confining pressure. Poisson's ratio and internal frictional coefficient have no obvious change as the temperature increases. Moreover, there is a transition from a brittle to ductile behavior when the temperature becomes high. At 900 °C, the granite shows an obvious elastic-plastic behavior.

Pyrolysis of polyethylene terephthalate containing real waste plastics using Ni loaded zeolite catalysts

NASA Astrophysics Data System (ADS)

Al-asadi, M.; Miskolczi, N.

2018-05-01

In this work the pyrolysis of polyethylene terephthalate (PET) containing real waste plastic was investigated using different Ni loaded catalysts: Ni/ZSM-5, Ni/y-zeolite, Ni/β-zeolite and Ni/natural zeolite (clinoptilolite). Raw materials were pyrolyzed in a horizontal tubular reactor between 600 and 900°C using 10% of catalysts. It was found, that both temperature increasing and catalysts presence can increase the gas yields, however owing to gasification reactions, the pyrolysis oil yield decreased with increasing temperature. Ni/y-zeolite catalyst had the most benefit in gas yield increasing at low temperature; however Ni/ZSM-5 showed advanced property in gas yield increasing at high temperature. Gases contained hydrogen, carbon oxides and hydrocarbons, which composition was significantly affected by catalysts. Ni loaded zeolites favoured to the formation of hydrogen and branched hydrocarbons; furthermore the concentrations of both CO and CO2 were also increased as function of elevated temperature. That phenomenon was attributed to the further decomposition of PET, especially to the side chain scission reactions. Owing to the Boudouard reaction, the ratio of CO2/CO can increased with temperature. Pyrolysis oils were the mixtures of n-saturated, n-unsaturated, branched, oxygen free aromatics and oxygenated hydrocarbons. Temperature increasing has a significant effect to the aromatization and isomerization reactions, while the catalysts can efficiently decreased the concentration of oxygen containing compounds.

Combined effects of ocean acidification and temperature on planula larvae of the moon jellyfish Aurelia coerulea.

PubMed

Dong, Zhijun; Sun, Tingting

2018-08-01

Rapidly rising levels of atmospheric CO 2 have caused two environmental stressors, ocean acidification and seawater temperature increases, which represent major abiotic threats to marine organisms. Here, we investigated for the first time the combined effects of ocean acidification and seawater temperature increases on the behavior, survival, and settlement of the planula larvae of Aurelia coerulea, which is considered a nuisance species around the world. Three pH levels (8.1, 7.7 and 7.3) and two temperature levels (24 °C and 27 °C) were used in the present study. There were no interactive effects of temperature and pH on the behavior, survival, and settlement of planula larvae of A. coerulea. We found that the swimming speed and mortality of the planula larvae of A. coerulea were significantly affected by temperature, and low pH significantly affected settlement. Planula larvae of A. coerulea from the elevated temperature treatment moved faster and showed higher mortality than those at the control temperature. The settlement rate of A. coerulea planulae was significantly higher at the pH level of 7.3 than at other pH levels. These results suggest that seawater temperature increase, rather than reduced pH, was the main stress factor affecting the survival of A. coerulea planulae. Overall, the planula larvae of the common jellyfish A. coerulea appeared to be resistant to ocean acidification, but may be negatively affected by future seawater temperature increases. Copyright © 2018 Elsevier Ltd. All rights reserved.

Interactive effects of near-future temperature increase and ocean acidification on physiology and gonad development in adult Pacific sea urchin, Echinometra sp . A

NASA Astrophysics Data System (ADS)

Uthicke, S.; Liddy, M.; Nguyen, H. D.; Byrne, M.

2014-09-01

Increased atmospheric CO2 will have a twofold impact on future marine ecosystems, increasing global sea surface temperatures and uptake of CO2 (Ocean Acidification). Many experiments focus on the investigation of one of these stressors, but under realistic future climate predictions, these stressors may have interactive effects on individuals. Here, we investigate the effect of warming and acidification in combination. We test for interactive effects of potential near-future (2100) temperature (+2 to 3 °C) and pCO2 (~860-940 μAtm) levels on the physiology of the tropical echinoid Echinometra sp . A. The greatest reduction in growth was under simultaneous temperature and pH/ pCO2 stress (marginally significant temperature × pH/ pCO2 interaction). This was mirrored by the physiological data, with highest metabolic activity (measured as respiration and ammonium excretion) occurring at the increased temperature and pCO2 treatment, although this was not significant for excretion. The perivisceral coelomic fluid pH was ~7.5-7.6, as typical for echinoids, and showed no significant changes between treatments. Indicative of active calcification, internal magnesium and calcium concentrations were reduced compared to the external medium, but were not different between treatments. Gonad weight was lower at the higher temperature, and this difference was more distinct and statistically significant for males. The condition of the gonads assessed by histology declined in increased temperature and low pH treatments. The Echinometra grew in all treatments indicating active calcification of their magnesium calcite tests even as carbonate mineral saturation decreased. Our results indicate that the interactive temperature and pH effects are more important for adult echinoids than individual stressors. Although adult specimens grow and survive in near-future conditions, higher energy demands may influence gonad development and thus population maintenance.

Evaluating the Effect of Ground Temperature on Phreatic Evaporation in Bare Soil Area

NASA Astrophysics Data System (ADS)

Manting, S.; Wang, B.; Liu, P.

2017-12-01

Phreatic water evaporation is an important link in water conversion, and it is also the main discharge of shallow groundwater. The influencing factors of phreatic evaporation intensity include meteorological elements, soil lithology, ground temperature, water table depth and plant growth status, etc. However, the effect of ground temperature on phreatic evaporation is neglected in the traditional phreatic evaporation study, while from the principle of water vapor conversion, the ground temperature is the main energy controlling the process. Taking the homogeneous sand in bare soil area for example, the effect of different temperature difference between ground temperature and air temperature on phreatic evaporation was studied by constructing soil column experiment and Hydrus numerical simulation model. Based on analysis of the process and trend of soil water content in different depths, the influence mechanism of ground temperature on phreatic evaporation was discussed quantitatively. The experimental results show that the change trend of daily evaporation is basically the same. But considering the effect of ground temperature the evaporation amount is significantly larger than that of without considering the temperature. When the temperature (-2.3 ° 13.6 °) is lower than the ground temperature (20 °), the average value of evaporation increased by about 33.7%; When the temperature (22 ° -33.2 °) is higher than the ground temperature (20 °), the average increase of evaporation is about 10.08%. The effect of ground temperature on the evaporation is very significant in winter and summer. Soil water content increased with the increase of water table depth, while the soil water content at the same depth was different due to the temperature difference, and the soil water content was also different. The larger the temperature difference, the greater the difference of soil water content. The slope of the trend line of the phreatic evaporation is also increased accordingly. That is, under the influence of ground temperature, water vapor conversion rate increased, resulting in increased soil moisture and increased phreatic evaporation. Therefore, considering the ground temperature, it has important theoretical and practical value for scientific understanding and revealing the phreatic evaporation process.

The Effect of Increased Temperatures and Ultraviolet Radiation on Dissolved Oxygen in Ecosystems Primarily Comprised of "Euglena"

ERIC Educational Resources Information Center

Carpenter, Matt

2009-01-01

The purpose of this study was to determine whether increased levels of UV radiation and temperatures from global warming have a significant impact on dissolved oxygen (DO) output from the alga, "Euglena," which affects other organisms in the ecosystem. The original hypothesis stated that if temperature was increased along with exposure time to…

The Effects of CO2 Injection and Barrel Temperatures on the Physiochemical and Antioxidant Properties of Extruded Cereals

PubMed Central

Thin, Thazin; Myat, Lin; Ryu, Gi-Hyung

2016-01-01

The effects of CO2 injection and barrel temperatures on the physiochemical and antioxidant properties of extruded cereals (sorghum, barley, oats, and millet) were studied. Extrusion was carried out using a twin-screw extruder at different barrel temperatures (80, 110, and 140°C), CO2 injection (0 and 500 mL/min), screw speed of 200 rpm, and moisture content of 25%. Extrusion significantly increased the total flavonoid content (TFC) of extruded oats, and β-glucan and protein digestibility (PD) of extruded barley and oats. In contrast, there were significant reductions in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, PD of extruded sorghum and millet, as well as resistant starch (RS) of extruded sorghum and barley, and total phenolic content (TPC) of all extrudates, except extruded millet. At a barrel temperature of 140°C, TPC in extruded barley was significantly increased, and there was also an increase in DPPH and PD in extruded millet with or without CO2 injection. In contrast, at a barrel temperature of 140°C, the TPC of extruded sorghum decreased, TFC of extruded oats decreased, and at a barrel temperature of 110°C, PD of extruded sorghum without CO2 decreased. Some physical properties [expansion ratio (ER), specific length, piece density, color, and water absorption index] of the extrudates were significantly affected by the increase in barrel temperature. The CO2 injection significantly affected some physical properties (ER, specific length, piece density, water solubility index, and water absorption index), TPC, DPPH, β-glucan, and PD. In conclusion, extruded barley and millet had higher potential for making value added cereal-based foods than the other cereals. PMID:27752504

Effects of climatic factors on plasma lipid levels: A 5-year longitudinal study in a large Chinese population.

PubMed

Zhou, Xiaoming; Lin, Haiyan; Zhang, Shigang; Ren, Jianwei; Wang, Zhe; Zhang, Yun; Wang, Mansen; Zhang, Qunye

2016-01-01

The rules and mechanisms of seasonal changes in plasma lipid levels, which may be related to annual rhythmicity of incidence and mortality of cardiovascular diseases, are still controversial. The objectives of this study were to study the effects of climatic factors on plasma lipid levels and to preliminarily reveal mechanisms of annual rhythmicity of plasma lipid levels. A longitudinal study was performed using health examination data of 5 consecutive years (47,270 subjects) in Jinan, China. The climate in Jinan is typical temperate continental monsoon climate with huge temperature difference between winter and summer (>30°C). After considering and adjusting those classical lipid-associated risk factors, such as age, gender, diet, exercise, blood pressure, body weight, change of body weight, body mass index, glycemia, alanine aminotransferase, and creatinine, only air temperature could still significantly affect plasma lipid levels among the main climatic factors (humidity, precipitation, and so forth). For men, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol was decreased significantly 0.35, 0.18, and 0.06 mmol/L, respectively, whereas triglyceride was increased significantly 0.12 mmol/L for every 10°C increase in air temperature. For women, total cholesterol and high-density lipoprotein cholesterol were decreased notably 0.73 and 0.32 mmol/L, and low-density lipoprotein cholesterol was increased significantly 0.26 mmol/L for every 10°C increase in air temperature, whereas triglyceride was not significantly affected by air temperature. Air temperature is an independent risk factor for plasma lipid levels besides those classical lipid-associated risk factors. The annual air temperature fluctuations might be an important mechanism of the seasonal changes of lipids. Copyright © 2016 National Lipid Association. Published by Elsevier Inc. All rights reserved.

[Response of indica rice spikelet differentiation and degeneration to air temperature and solar radiation of different sowing dates].

PubMed

Wang, Ya Liang; Zhang, Yu Ping; Xiang, Jing; Wang, Lei; Chen, Hui Zhe; Zhang, Yi Kai; Zhang, Wen Qian; Zhu, De Feng

2017-11-01

In this study, three rice varieties, including three-line hybrid indica rice Wuyou308 and Tianyouhuazhan, and inbred indica rice Huanghuazhan were used to investigate the effects of air temperature and solar radiation on rice growth duration and spikelet differentiation and degeneration. Ten sowing-date treatments were conducted in this field experiment. The results showed that the growth duration of three indica rice varieties were more sensitive to air temperature than to day-length. With average temperature increase of 1 ℃, panicle initiation advanced 1.5 days, but the panicle growth duration had no significant correlation with the temperature and day-length. The number of spikelets and differentiated spikelets revealed significant differences among different sowing dates. Increases in average temperature, maximum temperature, minimum temperature, effective accumulated temperature, temperature gap and the solar radiation benefited dry matter accumulation and spikelet differentiation of all varieties. With increases of effective accumulated temperature, diurnal temperature gap and solar radiation by 50 ℃, 1 ℃, 50 MJ·m -2 during panicle initiation stage, the number of differentiated spikelets increased 10.5, 14.3, 17.1 respectively. The rate of degenerated spikelets had a quadratic correlation with air temperature, extreme high and low temperature aggravated spikelets degeneration, and low temperature stress made worse effect than high temperature stress. The rate of spikelet degeneration dramatically rose with the temperature falling below the critical temperature, the critical effective accumulated temperature, daily average temperature, daily maximum temperature and minimum temperature during panicle initiation were 550-600 ℃, 24.0-26.0 ℃, 32.0-34.0 ℃, 21.0-23.0 ℃, respectively. In practice, the natural condition of appropriate high temperature, large diurnal temperature gap and strong solar radiation were conducive to spikelet differentiation, and hindered the spikelet degeneration.

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.

Characterizing fluorescent imaging properties of antibodies conjugated to IRDye800CW for use in imaging of head and neck cancer

NASA Astrophysics Data System (ADS)

Foster, Robert C.; Krell, Asher M.; Chung, Thomas K.; Warram, Jason M.; Zinn, Kurt R.; Rosenthal, Eben L.

2014-03-01

Introduction: Proteins conjugated to the near infrared (NIR) moieties for detection of head and neck cancers are being translated to the clinic. However, little is known about the fluorescent properties of IRDye800CW after conjugation to antibodies. We investigated factors that may alter the real-time observed fluorescence of antibody conjugated dye and the rate of fluorescent signal loss. Methods: Signal loss was examined using three FDA approved monoclonal antibodies conjugated to IRDye800CW (LICOR) over a period of 15 days. Temperature effects on fluorescence were examined for conjugated dye in both solution and a mouse tumor model. Samples were cooled to -20°C then warmed to predetermined temperatures up to 60°C with imaging performed using the PEARL Impulse (LI-COR) and LUNA (Novadaq) systems. Results: Short term fluorescent signal loss (< 1 hour) was linear, while long term loss (15 days) was exponential with significant increases in rate observed with light exposure and increased temperatures. Cooling of tumor tissue at -20°C was shown to significantly increase tumor fluorescence on both imaging modalities when compared to room temperature (p=0.008, p=0.019). Concurrently the ratio of tumor to background fluorescent signal (TBR) increased with decreasing temperature with statistically significant increases seen at -20°C and 4°C (p=0.0015, p=0.03). Conclusions: TBR is increased with decreasing sample temperature, suggesting that the clinical exam of fluorescently labeled tissues may be improved at cooler temperatures. Our results indicate that both the rate of signal loss and the change in fluorescence with temperature observed for IRDye800CW are independent of the conjugating antibody.

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

PubMed

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

2005-01-01

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

Effects of discharge chamber length on the negative ion generation in volume-produced negative hydrogen ion source

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

Chung, Kyoung-Jae; Jung, Bong-Ki; An, YoungHwa

2014-02-15

In a volume-produced negative hydrogen ion source, control of electron temperature is essential due to its close correlation with the generation of highly vibrationally excited hydrogen molecules in the heating region as well as the generation of negative hydrogen ions by dissociative attachment in the extraction region. In this study, geometric effects of the cylindrical discharge chamber on negative ion generation via electron temperature changes are investigated in two discharge chambers with different lengths of 7.5 cm and 11 cm. Measurements with a radio-frequency-compensated Langmuir probe show that the electron temperature in the heating region is significantly increased by reducingmore » the length of the discharge chamber due to the reduced effective plasma size. A particle balance model which is modified to consider the effects of discharge chamber configuration on the plasma parameters explains the variation of the electron temperature with the chamber geometry and gas pressure quite well. Accordingly, H{sup −} ion density measurement with laser photo-detachment in the short chamber shows a few times increase compared to the longer one at the same heating power depending on gas pressure. However, the increase drops significantly as operating gas pressure decreases, indicating increased electron temperatures in the extraction region degrade dissociative attachment significantly especially in the low pressure regime. It is concluded that the increase of electron temperature by adjusting the discharge chamber geometry is efficient to increase H{sup −} ion production as long as low electron temperatures are maintained in the extraction region in volume-produced negative hydrogen ion sources.« less

Temperature and pressure dependent thermodynamic behavior of 2H-CuInO2

NASA Astrophysics Data System (ADS)

Bhamu, K. C.

2018-05-01

Density functional theory and quasi-harmonic Debye model has been used to study the thermodynamic properties of 2H-CuInO2. At the optimized structural parameters, pressure (0 to 80 GPa) dependent variation in the various thermodynamic properties, i.e. unit cell volume (V), bulk modulus (B), specific heat (Cv), Debye temperature (θD), Grüneisen parameter (γ) and thermal expansion coefficient (α) are calculated for various temperature values. The results predict that the pressure has significant effect on unit cell volume and bulk modulus while the temperature shows negligible effect on both parameters. With increasing temperature thermal expansion coefficient increase while with increasing pressure it decreases. The specific heat remains close to zero for ambient pressure and temperature values and it increases with increasing temperature. It is observed that the pressure has high impact on Debye temperature and Grüneisen parameter instead of temperature. Debye temperature and Grüneisen parameter both remains almost constant for the temperature range (0-300K) while Grüneisen parameter decrease with increasing pressure at constant temperature and Debye temperature increases rapidly with increasing pressure. An increase in Debye temperature with respect to pressure shows that the thermal vibration frequency changes rapidly.

Brown adipose tissue thermogenesis does not explain the intra-administration hyperthermic sign-reversal induced by serial administrations of 60% nitrous oxide to rats.

PubMed

Al-Noori, Salwa; Ramsay, Douglas S; Cimpan, Andreas; Maltzer, Zoe; Zou, Jessie; Kaiyala, Karl J

2016-08-01

Initial administration of ≥60% nitrous oxide (N2O) to rats promotes hypothermia primarily by increasing whole-body heat loss. We hypothesized that the drug promotes heat loss via the tail and might initially inhibit thermogenesis via brown adipose tissue (BAT), major organs of thermoregulation in rodents. Following repeated administrations, N2O inhalation evokes hyperthermia underlain by increased whole-body heat production. We hypothesized that elevated BAT thermogenesis plays a role in this thermoregulatory sign reversal. Using dual probe telemetric temperature implants and infrared (IR) thermography, we assessed the effects of nine repeated 60% N2O administrations compared to control (con) administrations on core temperature, BAT temperature, lumbar back temperature and tail temperature. Telemetric core temperature, telemetric BAT temperature, and IR BAT temperature were reduced significantly during initial 60% N2O inhalation (p≤0.001 compared to con). IR thermography revealed that acute N2O administration unexpectedly reduced tail temperature (p=0.0001) and also inhibited IR lumbar temperature (p<0.0001). In the 9th session, N2O inhalation significantly increased telemetric core temperature (p=0.007) indicative of a hyperthermic sign reversal, yet compared to control administrations, telemetric BAT temperature (p=0.86), IR BAT temperature (p=0.85) and tail temperature (p=0.47) did not differ significantly. Thus, an initial administration of 60% N2O at 21°C may promote hypothermia via reduced BAT thermogenesis accompanied by tail vasoconstriction as a compensatory mechanism to limit body heat loss. Following repeated N2O administrations rats exhibit a hyperthermic core temperature but a normalized BAT temperature, suggesting induction of a hyperthermia-promoting thermogenic adaptation of unknown origin. Copyright © 2016 Elsevier Ltd. All rights reserved.

Progress and prospects of climate change impacts on hydrology in the arid region of northwest China.

PubMed

Chen, Yaning; Li, Zhi; Fan, Yuting; Wang, Huaijun; Deng, Haijun

2015-05-01

The arid region of Northwest China, located in the central Asia, responds sensitively to global climate change. Based on the newest research results, this paper analyzes the impacts of climate change on hydrology and the water cycle in the arid region of Northwest China. The analysis results show that: (1) In the northwest arid region, temperature and precipitation experienced "sharply" increasing in the past 50 years. The precipitation trend changed in 1987, and since then has been in a state of high volatility, during the 21st century, the increasing rate of precipitation was diminished. Temperature experienced a "sharply" increase in 1997; however, this sharp increasing trend has turned to an apparent hiatus since the 21st century. The dramatic rise in winter temperatures in the northwest arid region is an important reason for the rise in the average annual temperature, and substantial increases in extreme winter minimum temperature play an important role in the rising average winter temperature; (2) There was a significant turning point in the change of pan evaporation in the northwest arid area in 1993, i.e., in which a significant decline reversed to a significant upward trend. In the 21st century, the negative effects of global warming and increasing levels of evaporation on the ecology of the northwest arid region have been highlighted; (3) Glacier change has a significant impact on hydrology in the northwest arid area, and glacier inflection points have appeared in some rivers. The melting water supply of the Tarim River Basin possesses a large portion of water supplies (about 50%). In the future, the amount of surface water will probably remain at a high state of fluctuation. Copyright © 2015 Elsevier Inc. All rights reserved.

Evaluating the Impact of Global Warming on Water Balance of Maize by High-precision Controlled Experiment and MLCan model

NASA Astrophysics Data System (ADS)

Ma, Y.; Song, X.; Kumar, P.; Wu, Y.; Woo, D.; Le, P. V.; Ma, C.

2016-12-01

Increased temperature affects the agricultural hydrologic cycle not only by changing precipitation levels, evapotranspiration and the magnitude and timing of run-off, but also by impacting water flows and soil water dynamics. Accurate prediction of hydrologic change under global warming requires high-precision experiment and mathematical model to determine water interaction between interfaces in the soil-plant-atmosphere continuum. In this study, the weighting lysimeter and chamber were coupled to monitor water balance component dynamics of maize under controlled ambient temperature and elevated temperature of 2°C conditions. A mechanistic multilayer canopy-soil-root system model (MLCan) was used to predict hydrologic fluxes variation under different elevated temperature scenarios after calibration with experimental results. The results showed that maize growth period reduced 8 days under increased temperature of 2°C. The mean daily evapotranspiration, soil water storage change, and drainage was 2.66 mm, -2.75 mm, and 0.22 mm under controlled temperature condition, respectively. When temperature was elevated by 2°C, the average daily ET for maize significantly increased about 6.7% (p<0.05). However, there were non-significant impacts of increased temperature on the daily soil water storage change and drainage (p>0.05). Quantification of changes in water balance components induced by temperature increase for maize is critical for optimizing irrigation water management practices and improving water use efficiency.

Incorporation of 3H-thymidine by different prokaryotic groups in relation to temperature and nutrients in a lacustrine ecosystem.

PubMed

Boucher, Delphine; Richardot, Mathilde; Thénot, Aurélie; Debroas, Didier

2006-10-01

The incorporation of [3H-methyl] thymidine (3H-TdR) by Eubacteria, bacterial groups (alpha- and beta-Proteobacteria, Cytophaga-Flavobacter), and Archaea was measured according to temperature (7 and 17 degrees C) and nutrient levels (nitrogen, phosphorus, and carbon) in a lacustrine system (Sep, France). Short-term incubation was performed using a combination of microautoradiography and fluorescent in situ hybridization. Irrespective of the temperatures and nutrients studied, all the major phylogenetic bacterial groups assimilated 3H-TdR, and in most of the treatments studied, the proportion of beta-Proteobacteria taking up 3H-TdR was higher than those in the other bacterial groups. The proportion of Bacteria and different bacterial groups studied incorporating 3H-TdR were significantly increased, approximately 1.5-fold, by temperature except for alpha-Proteobacteria (7.6-fold). The nutrient effect was not the same for the different bacterial groups according to the temperatures studied. The proportions of alpha-Proteobacteria (at both temperatures) and Cytophaga-Flavobacter (at 7 degrees C) taking up 3H-TdR were significantly decreased and increased by adding N and P, respectively. Also, adding N, P, and C increased and decreased the percentage of beta-Proteobacteria incorporating 3H-TdR at 7 and 17 degrees C, respectively. The archaeal community showed a similar proportion of active cells (i.e., 3H-TdR) to the bacterial community, and uptake of 3H-TdR by Archaea was significantly increased (P < 0.05) by both temperature and nutrients. Thus, the assimilation of 3H-TdR by bacterial groups and Archaea in lacustrine system is significantly controlled by both temperature and nutrients.

Effects of long-term elevated temperature on covering, sheltering and righting behaviors of the sea urchin Strongylocentrotus intermedius

PubMed Central

Zhang, Lisheng; Zhang, Lingling; Shi, Dongtao; Wei, Jing; Chang, Yaqing

2017-01-01

Increases in ocean temperature due to climate change are predicted to change the behaviors of marine invertebrates. Altered behaviors of keystone ecosystem engineers such as echinoderms will have consequences for the fitness of individuals, which are expected to flow on to the local ecosystem. Relatively few studies have investigated the behavioral responses of echinoderms to long-term elevated temperature. We investigated the effects of exposure to long-term (∼31 weeks) elevated temperature (∼3 °C above the ambient water temperature) on covering, sheltering and righting behaviors of the sea urchin Strongylocentrotus intermedius. Long-term elevated temperature showed different effects on the three behaviors. It significantly decreased covering behavior, including both covering behavior reaction (time to first covering) and ability (number of covered sea urchins and number of shells used for covering). Conversely, exposure to long-term elevated temperature significantly increased sheltering behavior. Righting response in S. intermedius was not significantly different between temperature treatments. The results provide new information into behavioral responses of echinoderms to ocean warming. PMID:28348933

Daily temperature change in relation to the risk of childhood bacillary dysentery among different age groups and sexes in a temperate city in China.

PubMed

Li, K; Zhao, K; Shi, L; Wen, L; Yang, H; Cheng, J; Wang, X; Su, H

2016-02-01

In recent years, many studies have found that ambient temperature is significantly associated with bacillary dysentery (BD). However, there is limited evidence on the relationship between temperature and childhood BD in temperate areas. To investigate the relationship between daily mean temperature (MT) and childhood BD in China. Data on daily MT and childhood BD between 2006 and 2012 were collected from the Bureau of Meteorology and the Centre for Disease Control and Prevention in Hefei, Anhui Province, China. A Poisson generalized linear regression model combined with a distributed lag non-linear model was used to analyse the effects of temperature on childhood BD across different age and sex subgroups. An increase in temperature was significantly associated with childhood BD, and each 1 °C increase corresponded to an increase of 1.58% [95% confidence interval (CI) 0.46-2.71%] in the number of cases of BD. Children aged 0-5 years and girls were particularly sensitive to the effects of temperature. High temperatures may increase the risk of childhood BD in Hefei. Children aged 0-5 years and girls appear to be particularly sensitive to the effects of high temperature. Copyright © 2015 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Physiology response of the indigenous cattle breeds to the environment in West Sumbawa, Indonesia

NASA Astrophysics Data System (ADS)

Aritonang, S. B.; Yuniati, R.; Abinawanto, Imron, M.; Bowolaksono, A.

2017-07-01

Heat stress in cattle welfare is a growing concern because of increase in ambient temperature due to global warming. Physiological adaptation is as a way to survive and reproduce by regulation internal body temperature. West Sumbawa is a dry tropic area in eastern Indonesia where its temperature range is 24-38 °C and relative humidity is 50-90 %. This study aimed to determine the physiological response of indigenous cattle i.e. Bali cattle and Sumbawa Ongole cattle to the environment in West Sumbawa. Skin and rectal temperature and respiration rate within one minute were measured as physiology profiles from seven Bali cattle and two Sumbawa Ongole cattle. They were measured every 7.00 am and 15.00 pm for five consecutive days in August 2016. The results of measurements physiology profiles differ significantly between morning and afternoon among cattle breeds. Body temperature and respiration rate were significantly different among breeds (p < 0.05). Body temperature was lower but respiration rate of Sumbawa Ongole was higher than Bali cattle. Increased respiration rate of breeds was positively correlated with Temperature and Humidity Index (THI) value (p < 0.05), but neither was body temperature. Physiological response of Bali cattle to environmental West Sumbawa through the increase in body temperature, whereas Sumbawa Ongole cattle through increasing in respiration rate.

Temperature-dependent regulation of blood distribution in snakes.

PubMed

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

2011-05-01

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

Spatial distribution of temperature trends and extremes over Maharashtra and Karnataka States of India

NASA Astrophysics Data System (ADS)

Dhorde, Amit G.; Korade, Mahendra S.; Dhorde, Anargha A.

2017-10-01

Earth surface temperatures are changing worldwide together with the changes in the extreme temperatures. The present study investigates trends and variations of monthly maximum and minimum temperatures and their effects on seasonal fluctuations at different climatological stations of Maharashtra and Karnataka states of India. Trend analysis was performed on annual and seasonal mean maximum temperature (TMAX) and mean minimum temperature (TMIN) for the period 1969 to 2006. During the last 38 years, an increase in annual TMAX and TMIN has occurred. At most of the locations, the increase in TMAX was faster than the TMIN, resulting in an increase in diurnal temperature range. At the same time, annual mean temperature (TM) showed a significant increase over the study area. Percentiles were used to identify extreme temperature indices. An increase in occurrence of warm extremes was observed at southern locations, and cold extremes increased over the central and northeastern part of the study area. Occurrences of cold wave conditions have decreased rapidly compared to heat wave conditions.

The effect of temperature and body weight on the routine metabolic rate and postprandial metabolic response in mulloway, Argyrosomus japonicus.

PubMed

Pirozzi, Igor; Booth, Mark A

2009-09-01

Specific dynamic action (SDA) is the energy expended on the physiological processes associated with meal digestion and is strongly influenced by the characteristics of the meal and the body weight (BW) and temperature of the organism. This study assessed the effects of temperature and body weight on the routine metabolic rate (RMR) and postprandial metabolic response in mulloway, Argyrosomus japonicus. RMR and SDA were established at 3 temperatures (14, 20 and 26 degrees C). 5 size classes of mulloway ranging from 60 g to 1.14 kg were used to establish RMR with 3 of the 5 size classes (60, 120 and 240 g) used to establish SDA. The effect of body size on the mass-specific RMR (mg O(2) kg(-1) h(-1)) varied significantly depending on the temperature; there was a greater relative increase in the mass-specific RMR for smaller mulloway with increasing temperature. No statistical differences were found between the mass exponent (b) values at each temperature when tested against H(0): b=0.8. The gross RMR of mulloway (mg O(2) fish(-1) h(-1)) can be described as function of temperature (T; 14-26 degrees C) as: (0.0195T-0.0454)BW(g)(0.8) and the mass-specific RMR (mg O(2) kg(-1) h(-1)) can be described as: (21.042T-74.867)BW(g)(-0.2). Both SDA duration and time to peak SDA were influenced by temperature and body weight; SDA duration occurred within 41-89 h and peak time occurred within 17-38 h of feeding. The effect of body size on peak metabolic rate varied significantly depending on temperature, generally increasing with temperature and decreasing with increasing body size. Peak gross oxygen consumption (MO(2): mg O(2) fish(-1) h(-1)) scaled allometrically with BW. Temperature, but not body size, significantly affected SDA scope, although the difference was numerically small. There was a trend for MO(2) above RMR over the SDA period to increase with temperature; however, this was not statistically significant. The average proportion of energy expended over the SDA period (SDA coefficient) ranged from approximately 7-13% of the total DE intake while the proportion of total energy expended on SDA above RMR ranged from approximately 16-27%.

[Effect of temperature and salinity on intrinsic increasing rate of Moina mongolica Daddy (Cladocera: Moinidae) population].

PubMed

Wang, Y; He, Z

2001-02-01

The intrinsic increasing rate of Moina mongolica Daddy, a euryhaline cladocera species isolated from inland brackish lakes of northwestern China, was studied at 20 degrees C-33 degrees C and 5-40 ppt, respectively. The results showed that its intrinsic increasing rate (rm) increased with increasing temperature from 20 degrees C-30 degrees C, and sharply dropped with further increasing temperature up to 33 degrees C. The rm of M. mongolica was relatively high at low salinity, the highest at 10 ppt, but no significant difference at 20-40 ppt. Therefore, 25 degrees C-30 degrees C and 10 ppt could be optimal for the development of M. mongolica population, and its increasing potential would not be affected significantly by rearing this cladocera species in seawater for a long period.

Effects of Genotype and Growth Temperature on the Contents of Tannin, Phytate and In Vitro Iron Availability of Sorghum Grains

PubMed Central

Wu, Gangcheng; Johnson, Stuart K.; Bornman, Janet F.; Bennett, Sarita J.; Singh, Vijaya; Simic, Azra; Fang, Zhongxiang

2016-01-01

Background It has been predicted that the global temperature will rise in the future, which means crops including sorghum will likely be grown under higher temperatures, and consequently may affect the nutritional properties. Methods The effects of two growth temperatures (OT, day/night 32/21°C; HT 38/21°C) on tannin, phytate, mineral, and in vitro iron availability of raw and cooked grains (as porridge) of six sorghum genotypes were investigated. Results Tannin content significantly decreased across all sorghum genotypes under high growth temperature (P ≤0.05), while the phytate and mineral contents maintained the same level, increased or decreased significantly, depending on the genotype. The in vitro iron availability in most sorghum genotypes was also significantly reduced under high temperature, except for Ai4, which showed a pronounced increase (P ≤0.05). The cooking process significantly reduced tannin content in all sorghum genotypes (P ≤0.05), while the phytate content and in vitro iron availability were not significantly affected. Conclusions This research provides some new information on sorghum grain nutritional properties when grown under predicted future higher temperatures, which could be important for humans where sorghum grains are consumed as staple food. PMID:26859483

Temperature and population density effects on locomotor activity of Musca domestica (Diptera: Muscidae).

PubMed

Schou, T M; Faurby, S; Kjærsgaard, A; Pertoldi, C; Loeschcke, V; Hald, B; Bahrndorff, S

2013-12-01

The behavior of ectotherm organisms is affected by both abiotic and biotic factors. However, a limited number of studies have investigated the synergistic effects on behavioral traits. This study examined the effect of temperature and density on locomotor activity of Musca domestica (L.). Locomotor activity was measured for both sexes and at four densities (with mixed sexes) during a full light and dark (L:D) cycle at temperatures ranging from 10 to 40°C. Locomotor activity during daytime increased with temperature at all densities until reaching 30°C and then decreased. High-density treatments significantly reduced the locomotor activity per fly, except at 15°C. For both sexes, daytime activity also increased with temperature until reaching 30 and 35°C for males and females, respectively, and thereafter decreased. Furthermore, males showed a significantly higher and more predictable locomotor activity than females. During nighttime, locomotor activity was considerably lower for all treatments. Altogether the results of the current study show that there is a significant interaction of temperature and density on daytime locomotor activity of M. domestica and that houseflies are likely to show significant changes in locomotor activity with change in temperature.

Peri-OVLT E-series prostaglandins and core temperature do not increase after intravenous IL-1beta in pregnant rats.

PubMed

Fewell, James E; Eliason, Heather L; Auer, Roland N

2002-08-01

Rats have an attenuated febrile response to endogenous pyrogen near the term of pregnancy. Given the fundamental role of E-series prostaglandins (PGEs) in mediating the febrile response to blood-borne endogenous pyrogen, the present experiments were carried out to determine whether PGEs increase in the area surrounding the organum vasculosum laminae terminalis (peri-OVLT) of near-term pregnant (P) rats as in nonpregnant (NP) rats after intravenous (iv) administration of recombinant rat interleukin-1beta (rrIL-1beta). Core temperature was measured by telemetry and peri-OVLT interstitial fluid was sampled in 12 NP and 12 P chronically instrumented, Sprague-Dawley rats by microdialysis for determination of total PGEs by radioimmunoassay. Basal core temperatures were higher in NP compared with P rats (NP 37.9 degrees C +/- 0.5, P 36.9 degrees C +/- 0.4; P < 0.05), but basal peri-OVLT PGEs were similar in both groups (NP 260 +/- 153 pg/ml, P 278 +/- 177 pg/ml; P =not significant). Intravenous administration of rrIL-1beta to NP rats produced a significant increase in core temperature with a latency, magnitude, and duration of 10 min, 0.87 degrees C, and at least 170 min, respectively; peri-OVLT PGEs were increased significantly by 30 min and averaged 270% above basal levels throughout the experiment. In P rats, however, neither core temperature nor peri-OVLT PGEs increased significantly after iv administration of rrIL-1beta. Intravenous administration of vehicle did not significantly alter core temperature or peri-OVLT PGEs in either group of rats. Thus peri-OVLT PGEs do not increase in P rats as they do in NP rats after iv administration of rrIL-1beta. The mechanism of this interesting component of the maternal adaptation to pregnancy, which likely plays a major role in mediating the attenuated febrile response to endogenous pyrogen near the term of pregnancy, warrants further investigation.

A Study of Dielectric Properties of Proteinuria between 0.2 GHz and 50 GHz

PubMed Central

Mun, Peck Shen; Ting, Hua Nong; Ong, Teng Aik; Wong, Chew Ming; Ng, Kwan Hong; Chong, Yip Boon

2015-01-01

This paper investigates the dielectric properties of urine in normal subjects and subjects with chronic kidney disease (CKD) at microwave frequency of between 0.2 GHz and 50 GHz. The measurements were conducted using an open-ended coaxial probe at room temperature (25°C), at 30°C and at human body temperature (37°C). There were statistically significant differences in the dielectric properties of the CKD subjects compared to those of the normal subjects. Statistically significant differences in dielectric properties were observed across the temperatures for normal subjects and CKD subjects. Pearson correlation test showed the significant correlation between proteinuria and dielectric properties. The experimental data closely matched the single-pole Debye model. The relaxation dispersion and relaxation time increased with the proteinuria level, while decreasing with the temperature. As for static conductivity, it increased with proteinuria level and temperature. PMID:26066351

Effect of warm compress application on tissue temperature in healthy dogs.

PubMed

Millard, Ralph P; Towle-Millard, Heather A; Rankin, David C; Roush, James K

2013-03-01

To measure the effect of warm compress application on tissue temperature in healthy dogs. 10 healthy mixed-breed dogs. Dogs were sedated with hydromorphone (0.1 mg/kg, IV) and diazepam (0.25 mg/kg, IV). Three 24-gauge thermocouple needles were inserted to a depth of 0.5 cm (superficial), 1.0 cm (middle), and 1.5 cm (deep) into a shaved, lumbar, epaxial region to measure tissue temperature. Warm (47°C) compresses were applied with gravity dependence for periods of 5, 10, and 20 minutes. Tissue temperature was recorded before compress application and at intervals for up to 80 minutes after application. Control data were collected while dogs received identical sedation but with no warm compress. Mean temperature associated with 5 minutes of heat application at the superficial, middle, and deep depths was significantly increased, compared with the control temperature. Application for 10 minutes significantly increased the temperature at all depths, compared with 5 minutes of application. Mean temperature associated with 20 minutes of application was not different at the superficial or middle depths, compared with 10 minutes of application. Temperature at the deep depth associated with 10 minutes of application was significantly higher, compared with 20 minutes of application, but all temperature increases at this depth were minimal. Results suggested that application of a warm compress should be performed for 10 minutes. Changes in temperature at a tissue depth of 1.5 cm were minimal or not detected. The optimal compress temperature to achieve therapeutic benefits was not determined.

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

PubMed

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

2003-09-01

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

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

PubMed

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

2018-01-01

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

Changes of body temperature and thermoregulatory responses of freely moving rats during GABAergic pharmacological stimulation to the preoptic area and anterior hypothalamus in several ambient temperatures.

PubMed

Ishiwata, Takayuki; Saito, Takehito; Hasegawa, Hiroshi; Yazawa, Toru; Kotani, Yasunori; Otokawa, Minoru; Aihara, Yasutsugu

2005-06-28

Action of gamma-aminobutyric acid (GABA) in the preoptic area and anterior hypothalamus (PO/AH) has been implicated to regulate body temperature (T(b)). However, its precise role in thermoregulation remains unclear. Moreover, little is known about its release pattern in the PO/AH during active thermoregulation. Using microdialysis and telemetry techniques, we measured several parameters related to thermoregulation of freely moving rats during pharmacological stimulation of GABA in normal (23 degrees C), cold (5 degrees C), and hot (35 degrees C) ambient temperatures. We also measured extracellular GABA levels in the PO/AH during cold (5 degrees C) and heat (35 degrees C) exposure combined with microdialysis and high performance liquid chromatography (HPLC). Perfusion of GABA(A) agonist muscimol into the PO/AH increased T(b), which is associated with increased heart rate (HR), as an index of heat production in all ambient temperatures. Although tail skin temperature (T(tail)) as an index of heat loss increased only under normal ambient temperatures, its response was relatively delayed in comparison with HR and T(b), suggesting that the increase in T(tail) was a secondary response to increased HR and T(b). Locomotor activity also increased in all ambient temperatures, but its response was not extraordinary. Interestingly, thermoregulatory responses were different after perfusion of GABA(A) antagonist bicuculline at each ambient temperature. In normal ambient temperature conditions, perfusion of bicuculline had no effect on any parameter. However, under cold ambient temperature, the procedure induced significant hypothermia concomitant with a decrease in HR in spite of hyperactivity and increase of T(tail). It induced hyperthermia with the increase of HR but no additional change of T(tail) in hot ambient temperature conditions. Furthermore, the extracellular GABA level increased significantly during cold exposure. Its release was lower during heat exposure than in a normal environment. These results indicate that GABA in the PO/AH is an important neurotransmitter for disinhibition of heat production and inhibition of heat loss under cold ambient temperature. It is a neurotransmitter for inhibition of heat production under hot ambient temperature.

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

Effects of Heat Wave on Body Temperature and Blood Pressure in the Poor and Elderly

PubMed Central

Kim, Soyeon; Cheong, Hae-Kwan; Ahn, Byungok; Choi, Kyusik

2012-01-01

Objectives We aimed to investigate the acute effects of heat stress on body temperature and blood pressure of elderly individuals living in poor housing conditions. Methods Repeated measurements of the indoor temperature, relative humidity, body temperature, and blood pressure were conducted for 20 elderly individuals living in low-cost dosshouses in Seoul during hot summer days in 2010. Changes in the body temperature, systolic blood pressure (SBP) and diastolic blood pressure (DBP) according to variations in the indoor and outdoor temperature and humidity were analyzed using a repeated-measures ANOVA controlling for age, sex, alcohol, and smoking. Results Average indoor and outdoor temperatures were 31.47℃ (standard deviation [SD], 0.97℃) and 28.15℃ (SD, 2.03℃), respectively. Body temperature increased by 0.21℃ (95% confidence interval [CI], 0.16 to 0.26℃) and 0.07℃ (95% CI, 0.04 to 0.10℃) with an increase in the indoor and outdoor temperature of 1℃. DBP decreased by 2.05 mmHg (95% CI, 0.05 to 4.05 mmHg), showing a statistical significance, as the indoor temperature increased by 1℃, while it increased by 0.20 mmHg (95% CI, -0.83 to 1.22 mmHg) as outdoor temperature increased by 1℃. SBP decreased by 1.75 mmHg (95% CI, -1.11 to 4.61 mmHg) and 0.35 mmHg (95% CI, -1.04 to 1.73 mmHg), as the indoor and outdoor temperature increased by 1℃, respectively. The effects of relative humidity on SBP and DBP were not statistically significant for both indoor and outdoor. Conclusions The poor and elderly are directly exposed to heat waves, while their vital signs respond sensitively to increase in temperature. Careful adaptation strategies to climate change considering socioeconomic status are therefore necessary. PMID:22888472

Effects of heat wave on body temperature and blood pressure in the poor and elderly.

PubMed

Kim, Young-Min; Kim, Soyeon; Cheong, Hae-Kwan; Ahn, Byungok; Choi, Kyusik

2012-01-01

We aimed to investigate the acute effects of heat stress on body temperature and blood pressure of elderly individuals living in poor housing conditions. Repeated measurements of the indoor temperature, relative humidity, body temperature, and blood pressure were conducted for 20 elderly individuals living in low-cost dosshouses in Seoul during hot summer days in 2010. Changes in the body temperature, systolic blood pressure (SBP) and diastolic blood pressure (DBP) according to variations in the indoor and outdoor temperature and humidity were analyzed using a repeated-measures ANOVA controlling for age, sex, alcohol, and smoking. Average indoor and outdoor temperatures were 31.47℃ (standard deviation [SD], 0.97℃) and 28.15℃ (SD, 2.03℃), respectively. Body temperature increased by 0.21℃ (95% confidence interval [CI], 0.16 to 0.26℃) and 0.07℃ (95% CI, 0.04 to 0.10℃) with an increase in the indoor and outdoor temperature of 1℃. DBP decreased by 2.05 mmHg (95% CI, 0.05 to 4.05 mmHg), showing a statistical significance, as the indoor temperature increased by 1℃, while it increased by 0.20 mmHg (95% CI, -0.83 to 1.22 mmHg) as outdoor temperature increased by 1℃. SBP decreased by 1.75 mmHg (95% CI, -1.11 to 4.61 mmHg) and 0.35 mmHg (95% CI, -1.04 to 1.73 mmHg), as the indoor and outdoor temperature increased by 1℃, respectively. The effects of relative humidity on SBP and DBP were not statistically significant for both indoor and outdoor. The poor and elderly are directly exposed to heat waves, while their vital signs respond sensitively to increase in temperature. Careful adaptation strategies to climate change considering socioeconomic status are therefore necessary.

Atmospheric carbon dioxide and chlorofluoromethanes - Combined effects on stratospheric ozone, temperature, and surface temperature

NASA Technical Reports Server (NTRS)

Callis, L. B.; Natarajan, M.

1981-01-01

The effects of combined CO2 and CFCl3 and CF2Cl2 time-dependent scenarios on atmospheric O3 and temperature are described; the steady-state levels of O3 and surface temperature, to which the chlorofluoromethane scenario tends in the presence of twice and four time ambient CO2, are examined; and surface temperature changes, caused by the combined effects, are established. A description of the model and of the experiments is presented. Results indicate that (1) the total ozone time history is significantly different from that due to the chlorofluoromethane alone; (2) a local ozone minimum occurs in the upper stratosphere about 45 years from the present with a subsequent ozone increase, then decline; and (3) steady-state solutions indicate that tropospheric temperature and water vapor increases, associated with increased infrared opacity, cause significant changes in tropospheric ozone levels for 2 x CO2 and 4 x CO2, without the addition of chlorofluoromethanes.

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

PubMed

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

2015-12-01

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

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

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

Thermal physiology of the fingered limpet Lottia digitalis under emersion and immersion.

PubMed

Bjelde, Brittany E; Todgham, Anne E

2013-08-01

Marine animals living high in the rocky intertidal zone experience long durations of aerial emersion, sometimes enduring rapid increases in temperature. To date, much of our understanding of the thermal physiology of intertidal organisms comes from studies in which organisms are exposed to increasing temperatures when immersed, with the added effect of aerial emersion rarely considered. In this study, we examined the physiological response of the finger limpet, Lottia digitalis, to increases in temperature under both immersed and emersed conditions. We investigated the thermal sensitivity and upper temperature tolerance of limpets through assessment of cardiac performance, metabolic rate, glycogen depletion and maintenance of protein integrity. Cardiac performance in response to ecologically relevant increases in temperature was similar in emersed and immersed limpets from 15 to 35°C and showed multiple break patterns in heart rate as temperature was increased. Overall, emersed limpets had a greater upper thermal limit on cardiac performance, with the ability to maintain heart rate at a temperature 3-5°C higher than that for immersed limpets. Metabolism in limpets also differed significantly between emersion and immersion, where a significant depression in aerobic metabolic rate was observed under immersion with increasing temperature. Greater levels of ubiquitin-conjugated proteins were found under emersed conditions compared with immersed limpets. Maintaining cardiac performance and aerobic metabolism to higher temperatures under emersed conditions is likely reflective of physiological adaptations to live in an aerially exposed environment. Measured field temperatures where fingered limpets were collected demonstrated that limpets have a narrow thermal safety margin for aerobic performance, and currently experience multiple days where summer temperatures might exceed their threshold limits.

Effects of elevated temperature postharvest on color aspect, physiochemical characteristics, and aroma components of pineapple fruits.

PubMed

Liu, Chuanhe; Liu, Yan

2014-12-01

In this work, 2 separate experiments were performed to describe the influence of elevated temperature treatments postharvest on the color, physiochemical characteristics and aroma components of pineapple fruits during low-temperature seasons. The L* (lightness) values of the skin and pulp of pineapple fruits were decreased. The a* (greenness-redness) and b* (blueness-yellowness) values of the skin and pulp were all markedly increased. The elevated temperature significantly increased the contents of total soluble solids (TSS) and slightly affected contents of vitamin C (nonsignificant). Titratable acidity (TA) of pineapple fruits were notably decreased, whereas the values of TSS/TA of pineapple fruits were significantly increased. The firmness of the pineapple fruits decreased and more esters and alkenes were identified. The total relative contents of esters were increased, and the total relative contents of alkenes were decreased. © 2014 Institute of Food Technologists®

Nanosecond laser-induced damage at different initial temperatures of Ta{sub 2}O{sub 5} films prepared by dual ion beam sputtering

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

Xu, Cheng, E-mail: xucheng@cumt.edu.cn; Jia, Jiaojiao; Fan, Heliang

2014-08-07

Ta{sub 2}O{sub 5} films were deposited by dual ion beam sputtering method. The nanosecond laser-induced damage threshold (LIDT) at different initial temperatures and time of the films was investigated by an in situ high temperature laser-induced damage testing platform. It was shown that, when the initial temperature increased from 298 K to 383 K, the LIDT at 1064 nm and 12 ns significantly decreased by nearly 14%. Then the LIDT at 1064 nm and 12 ns decreased slower with the same temperature increment. Different damage morphologies were found at different initial temperatures. At low initial temperatures, it was the defects-isolated damage while at high initial temperaturesmore » it was the defects-combined damage. The theoretical calculations based on the defect-induced damage model revealed that both the significant increase of the highest temperature and the duration contributed to the different damage morphologies. With the initial temperature being increased, the thermal-stress coupling damage mechanism transformed gradually to the thermal dominant damage mechanism.« less

The influence of temperature and humidity on the incidence of hand, foot, and mouth disease in Japan.

PubMed

Onozuka, Daisuke; Hashizume, Masahiro

2011-12-01

The increasing evidence for rapid global climate change has highlighted the need for investigations examining the relationship between weather variability and infectious diseases. However, the impact of weather fluctuations on hand, foot, and mouth disease (HFMD), which primarily affects children, is not well understood. We acquired data related to cases of HFMD and weather parameters of temperature and humidity in Fukuoka, Japan between 2000 and 2010, and used time-series analyses to assess the possible relationship of weather variability with pediatric HFMD cases, adjusting for seasonal and interannual variations. Our analysis revealed that the weekly number of HFMD cases increased by 11.2% (95% CI: 3.2-19.8) for every 1°C increase in average temperature and by 4.7% (95% CI: 2.4-7.2) for every 1% increase in relative humidity. Notably, the effects of temperature and humidity on HFMD infection were most significant in children under the age of 10 years. Our study provides quantitative evidence that the number of HFMD cases increased significantly with increasing average temperature and relative humidity, and suggests that preventive measures for limiting the spread of HFMD, particularly in younger children, should be considered during extended periods of high temperature and humidity. Copyright © 2011 Elsevier B.V. All rights reserved.

Measurements of water temperature in fountains as an indicator of potential secondary water pollution caused by Legionella bacteria

NASA Astrophysics Data System (ADS)

Bąk, Joanna

2018-02-01

At high air temperatures persisting for a long time, water temperature in the fountains may also increase significantly. This can cause a sudden and significant increase in Legionella bacteria, which results in secondary water contamination. This phenomenon with water - air aerosol generated by fountains can be very dangerous for people. During the test, water temperature measurements in fountains in Poland were made. These research tests was conducted in the spring and summer. The research was conducted in order to determine whether there is a possibility of growth of Legionella bacteria. One of the aims of the study was to determine what temperature range occurs in the fountains and how the temperature changes in the basin of the fountain and when the highest temperature occurs. Single temperature measurements were made and also the temperature distribution was measured during daylight hours. The water temperature in most cases was greater than 20°C, but in no case exceed 26°C. The paper presents also the review about the effect of water temperature on the presence and bacterial growth. The study confirmed the existence of the risk of increasing the number of bacteria of the genus Legionella in the water in the fountains.

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.

[Correlation analysis on normalized difference vegetation index (NDVI) of different vegetations and climatic factors in Southwest China].

PubMed

Zhang, Yuan-Dong; Zhang, Xiao-He; Liu, Shi-Rong

2011-02-01

Based on the 1982-2006 NDVI remote sensing data and meteorological data of Southwest China, and by using GIS technology, this paper interpolated and extracted the mean annual temperature, annual precipitation, and drought index in the region, and analyzed the correlations of the annual variation of NDVI in different vegetation types (marsh, shrub, bush, grassland, meadow, coniferous forest, broad-leaved forest, alpine vegetation, and cultural vegetation) with corresponding climatic factors. In 1982-2006, the NDVI, mean annual temperature, and annual precipitation had an overall increasing trend, and the drought index decreased. Particularly, the upward trend of mean annual temperature was statistically significant. Among the nine vegetation types, the NDVI of bush and mash decreased, and the downward trend was significant for bush. The NDVI of the other seven vegetation types increased, and the upward trend was significant for coniferous forest, meadow, and alpine vegetation, and extremely significant for shrub. The mean annual temperature in the areas with all the nine vegetation types increased significantly, while the annual precipitation had no significant change. The drought index in the areas with marsh, bush, and cultural vegetation presented an increasing trend, that in the areas with meadow and alpine vegetation decreased significantly, and this index in the areas with other four vegetation types had an unobvious decreasing trend. The NDVI of shrub and coniferous forest had a significantly positive correlation with mean annual temperature, and that of shrub and meadow had significantly negative correlation with drought index. Under the conditions of the other two climatic factors unchanged, the NDVI of coniferous forest, broad-leaved forest, and alpine vegetation showed the strongest correlation with mean annual temperature, that of grass showed the strongest correlation with annual precipitation, and the NDVI of mash, shrub, grass, meadow, and cultural vegetation showed the strongest correlation with drought index. There existed definite correlations among the climatic factors. If the correlations among the climatic factors were ignored, the significant level of the correlations between NDVI and climatic factors would be somewhat reduced.

Suitable Water Flow and Water Temperature Difference of Blast Furnace

NASA Astrophysics Data System (ADS)

Zuo, Hai-bin; Li, Qian; Zhang, Jian-liang; Shen, Meng; Tie, Jin-yan; Jiao, Ke-xin

This paper designs three factors such as temperature, pH, conductivity and three levels of orthogonal test. Temperature is a significant factor. However PH and conductivity are not significant through poor analysis. Further research is conducted on the temperature. Temperature stability is 50°C. Suitable water velocity is 2.3m/s, which is calculated based on the largest part of the heat flux intensity and the corresponding water temperature should be controlled with 1.5°C. Meanwhile, water velocity increased has little effect on the heat transfer capabilities.

Effects of storage time and temperature on pH, specific gravity, and crystal formation in urine samples from dogs and cats.

PubMed

Albasan, Hasan; Lulich, Jody P; Osborne, Carl A; Lekcharoensuk, Chalermpol; Ulrich, Lisa K; Carpenter, Kathleen A

2003-01-15

To determine effects of storage temperature and time on pH and specific gravity of and number and size of crystals in urine samples from dogs and cats. Randomized complete block design. 31 dogs and 8 cats. Aliquots of each urine sample were analyzed within 60 minutes of collection or after storage at room or refrigeration temperatures (20 vs 6 degrees C [68 vs 43 degrees F]) for 6 or 24 hours. Crystals formed in samples from 11 of 39 (28%) animals. Calcium oxalate (CaOx) crystals formed in vitro in samples from 1 cat and 8 dogs. Magnesium ammonium phosphate (MAP) crystals formed in vitro in samples from 2 dogs. Compared with aliquots stored at room temperature, refrigeration increased the number and size of crystals that formed in vitro; however, the increase in number and size of MAP crystals in stored urine samples was not significant. Increased storage time and decreased storage temperature were associated with a significant increase in number of CaOx crystals formed. Greater numbers of crystals formed in urine aliquots stored for 24 hours than in aliquots stored for 6 hours. Storage time and temperature did not have a significant effect on pH or specific gravity. Urine samples should be analyzed within 60 minutes of collection to minimize temperature- and time-dependent effects on in vitro crystal formation. Presence of crystals observed in stored samples should be validated by reevaluation of fresh urine.

Rising stream and river temperatures in the United States

Treesearch

Sujay S. Kaushal; Gene E. Likens; Norbert A. Jaworski; Michael L. Pace; Ashley M. Sides; David Seekell; Kenneth T. Belt; David H. Secor; Rebecca L. Wingate

2010-01-01

Water temperatures are increasing in many streams and rivers throughout the US. We analyzed historical records from 40 sites and found that 20 major streams and rivers have shown statistically significant, long-term warming. Annual mean water temperatures increased by 0.009-0.077°C yr-1, and rates of warming were most rapid in, but not...

Can't take the heat: Temperature-enhanced toxicity in the mayfly Isonychia bicolor exposed to the neonicotinoid insecticide imidacloprid.

PubMed

Camp, A A; Buchwalter, D B

2016-09-01

Neonicotinoid insecticide usage has increased globally in recent decades. Neonicotinoids, such as imidacloprid, are potent insect neurotoxicants that may pose a threat to non-target aquatic organisms, such as aquatic insects. In nature, insects typically live in thermally fluctuating conditions, which may significantly alter both contaminant exposures and affects. Here we investigate the relationship between temperature and time-to-effect for imidacloprid toxicity with the aquatic insect Isonychia bicolor, a lotic mayfly. Additionally, we examined the mechanisms driving temperature-enhanced toxicity including metabolic rate, imidacloprid uptake rate, and tissue bioconcentration. Experiments included acute toxicity tests utilizing sublethal endpoints and mortality, as well as respirometry and radiotracer assays with [(14)C] imidacloprid. Further, we conducted additional uptake experiments with a suite of aquatic invertebrates (including I. bicolor, Neocloeon triangulifer, Macaffertium modestum, Pteronarcys proteus, Acroneuria carolinensis, and Pleuroceridae sp) to confirm and contextualize our findings from initial experiments. The 96h EC50 (immobility) for I. bicolor at 15°C was 5.81μg/L which was approximately 3.2 fold lower than concentrations associated with 50% mortality. Assays examining the impact of temperature were conducted at 15, 18, 21, and 24°C and demonstrated that time-to-effect for sublethal impairment and immobility was significantly decreased with increasing temperature. Uptake experiments with [(14)C] imidacloprid revealed that initial uptake rates were significantly increased with increasing temperature for I. bicolor, as were oxygen consumption rates. Further, in the separate experiment with multiple species across temperatures 15, 20, and 25°C, we found that all the aquatic insects tested had significantly increased imidacloprid uptake with increasing temperatures, with N. triangulifer accumulating the most imidacloprid on a mass-specific basis. Our acute toxicity results highlight the importance of evaluating sublethal endpoints, as profound impairments of motor function were evident far before mortality. Further, we demonstrate that temperature is a powerful modulator of sublethal toxicity within a range of environmentally relevant temperatures, impacting both uptake rates and metabolic rates of I. bicolor. Finally, we show that temperature alters imidacloprid uptake across a range of species, highlighting the physiological variation present within aquatic invertebrate communities and the challenge associated with relying solely on surrogate species. Taken together, this research points to the need to consider the role of temperature in toxicity assessments. Copyright © 2016 Elsevier B.V. All rights reserved.

Estrus- and steroid-induced changes in circadian rhythms in a diurnal rodent, Octodon degus.

PubMed

Labyak, S E; Lee, T M

1995-09-01

Diurnal Octodon degus exhibited marked alterations in activity and temperature in conjunction with the 3 wk estrous cycle when housed in LD12:12 light cycle. On the day of estrus, mean daily activity increases 109%, mean core temperature rises .4 degree C, activity onset is advanced 2 h, and amplitudes of both rhythms decline compared with the 3 days prior to estrus. On the day following estrus, activity onset was delayed 4.9 h, and mean activity and core temperature fell below that of the preestrus period. Ovariectomy significantly reduced mean temperature (.98 degree C) but did not significantly alter mean activity, and eliminated cyclic effects of estrus. Estrogen replacement led to a nonsignificant elevation in mean activity and core temperature with no change in the phase angle of entrainment. Progesterone replacement significantly reduced mean core temperature and mean activity, while only the phase angle difference between temperature minimum and activity onset was significantly altered. Intact degus maintained in constant darkness displayed only transient fluctuations in activity onset and temperature minimum during and after estrus. Estrogen or progesterone treatment of ovariectomized, free-running degus altered mean temperature and activity levels, but did not influence tau. Changes in phase angle of entrainment during estrus are not the result of hormone effects on the circadian clock but likely reflect increased or decreased levels of activity.

Toxic effects of juvenile sablefish, Anoplopoma fimbria by ammonia exposure at different water temperature.

PubMed

Kim, Jun-Hwan; Park, Hee-Ju; Hwang, In-Ki; Han, Jae-Min; Kim, Do-Hyung; Oh, Chul Woong; Lee, Jung-Sick; Kang, Ju-Chan

2017-09-01

Juvenile sablefish, Anoplopoma fimbria (mean length 17.1±2.4cm, and mean weight 75.6±5.7g) were used to evaluate toxic effects on antioxidant systems, immune responses, and stress indicators by ammonia exposure (0, 0.25, 0.75, and 1.25mg/L) at different water temperature (12 and 17°C) in 1 and 2 months. In antioxidant responses, superoxide dismutase (SOD) and catalase (CAT) were significantly increased by ammonia exposure, whereas glutathione (GSH) was decreased. In immune responses, lysozyme and phagocytosis activity were significantly increased by ammonia exposure. In stress indicators, plasma glucose, heat shock protein 70 (HSP 70), and cortisol were significantly increased. At high water temperature (17°C), alterations by ammonia exposure were more distinctly. The results of this study indicated that ammonia exposure can induce toxic effects in the sablefish, and high water temperature can affect the ammonia exposure toxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

Tracheal climate in laryngectomees after use of a heat and moisture exchanger.

PubMed

Keck, Tilman; Dürr, Jochen; Leiacker, Richard; Rettinger, Gerhard; Rozsasi, Ajnacska

2005-03-01

Heat and moisture exchangers (HME) are frequently used in the treatment and prevention of tracheobronchial dryness and infections. In this study, the short-term influence of the HME Prim-Air System (Heimomed, Kerpen, Germany) in laryngectomized patients was tested. Prospective study. After adaptation to the laboratory environment, tracheal humidity and temperature were measured before HME application, 1 minute after HME application, 10 minutes after HME application, 1 minute after removal of the HME, and 10 minutes after removal of the HME. When the HME was placed on the tracheal stoma, the end-inspiratory humidity and temperature increased significantly. Ten minutes after commencement of use of the HME, tracheal humidity further increased significantly. Ten minutes after removal of the HME, tracheal humidity and temperature decreased to values as before start of use of HME. The results indicate that short-term use of the HME Prim-Air system rapidly changes the tracheal climate. The significant increase in tracheal temperature and humidity may have beneficial effects on tracheal dryness in laryngectomized patients.

Relationships between weather and myocardial infarction: a biometeorological approach.

PubMed

Morabito, Marco; Modesti, Pietro Amedeo; Cecchi, Lorenzo; Crisci, Alfonso; Orlandini, Simone; Maracchi, Giampiero; Gensini, Gian Franco

2005-12-07

To calculate threshold values of weather discomfort which increase the risk of hospital admissions for myocardial infarction in winter and summer. Notwithstanding heat waves were reported to acutely increase hospital admissions for cardiovascular diseases, large surveys failed to reveal any increase of event rates with increasing air temperature. However, the assessment of air temperature does not allow evaluation of the actual discomfort perception caused by the combination of different meteorological parameters. Hospital admissions for myocardial infarction for the period 1998-2002 in Florence, Italy, were considered. The percentages of variation of daily event rates according to daily mean air temperature variations were preliminary derived by using a regression analysis. An alternative biometeorological approach, considering the Apparent Temperature Index (ATI) in summer, and the New U.S./Canada Wind Chill Temperature Index (NWCTI) in winter, which combine air temperature, relative humidity and wind velocity, was then used. The traditional approach showed that daily event rates significantly increased with daily mean air temperature decrease (10 degrees C decrease were associated with 19% increase in daily event rates for people older than 65 years), but failed to show any negative effect caused by hot climatic conditions. Conversely the biometeorological approach allowed to show that at least 9 h per day of severe discomfort caused by hot conditions significantly increased the rate of admission (P<0.01). This approach might be useful for the development of an operative weather watch/warning system for population and for hospital professional care.

Interaction Between Neuronal NOS Signaling and Temperature Influences SR Ca2+ Leak:Role of Nitroso-Redox Balance

PubMed Central

Dulce, Raul A.; Mayo, Vera; Rangel, Erika B.; Balkan, Wayne; Hare, Joshua M.

2014-01-01

Rationale While nitric oxide (NO) signaling modulates cardiac function and excitation-contraction coupling, opposing results due to inconsistent experimental conditions, particularly with respect to temperature, confound the ability to elucidate NO signaling pathways. Here we show that temperature significantly modulates NO effects. Objective Test the hypothesis that temperature profoundly impacts nitroso-redox equilibrium, thereby affecting sarcomeric reticulum (SR) Ca2+ leak. Methods and Results We measured SR Ca2+ leak in cardiomyocytes from wild-type (WT), NO/redox imbalance (NOS1−/−), and hyper S-nitrosylation (GSNOR−/−) mice. In WT cardiomyocytes, SR Ca2+ leak increased as temperature decreased from 37°C to 23°C, whereas, in NOS1−/ −cells, the leak suddenly increased when the temperature surpassed 30°C. GSNOR−/ − cardiomyocytes exhibited low leak throughout the temperature range. Exogenously added NO had a biphasic effect on NOS1−/− cardiomyocytes; reducing leak at 37°C but increasing it at sub-physiologic temperatures. Oxypurinol and Tempol diminished the leak in NOS1−/ − cardiomyocytes. Cooling from 37° to 23°C increased ROS generation in WT but decreased it in NOS1−/− cardiomyocytes. Oxypurinol further reduced ROS generation. At 23°C in WT cells, leak was decreased by tetrahydrobiopterin, an essential NOS cofactor. Cooling significantly increased SR Ca2+ content in NOS1−/− cells but had no effect in WT or GSNOR−/−. Conclusions Ca2+ leak and temperature are normally inversely proportional, whereas NOS1 deficiency reverses this effect, increasing leak and elevating ROS production as temperature increases. Reduced denitrosylation (GSNOR deficiency) eliminates the temperature dependence of leak. Thus, temperature regulates the balance between NO and ROS which in turn has a major impact on SR Ca2+. PMID:25326127

Interaction between neuronal nitric oxide synthase signaling and temperature influences sarcoplasmic reticulum calcium leak: role of nitroso-redox balance.

PubMed

Dulce, Raul A; Mayo, Vera; Rangel, Erika B; Balkan, Wayne; Hare, Joshua M

2015-01-02

Although nitric oxide (NO) signaling modulates cardiac function and excitation-contraction coupling, opposing results because of inconsistent experimental conditions, particularly with respect to temperature, confound the ability to elucidate NO signaling pathways. Here, we show that temperature significantly modulates NO effects. To test the hypothesis that temperature profoundly affects nitroso-redox equilibrium, thereby affecting sarcoplasmic reticulum (SR) calcium (Ca(2+)) leak. We measured SR Ca(2+) leak in cardiomyocytes from wild-type (WT), NO/redox imbalance (neuronal nitric oxide synthase-deficient mice-1 [NOS1(-/-)]), and hyper S-nitrosoglutathione reductase-deficient (GSNOR(-/-)) mice. In WT cardiomyocytes, SR Ca(2+) leak increased because temperature decreased from 37°C to 23°C, whereas in NOS1(-/-) cells, the leak suddenly increased when the temperature surpassed 30°C. GSNOR(-/-) cardiomyocytes exhibited low leak throughout the temperature range. Exogenously added NO had a biphasic effect on NOS1(-/-) cardiomyocytes; reducing leak at 37°C but increasing it at subphysiological temperatures. Oxypurinol and Tempol diminished the leak in NOS1(-/-) cardiomyocytes. Cooling from 37°C to 23°C increased reactive oxygen species generation in WT but decreased it in NOS1(-/-) cardiomyocytes. Oxypurinol further reduced reactive oxygen species generation. At 23°C in WT cells, leak was decreased by tetrahydrobiopterin, an essential NOS cofactor. Cooling significantly increased SR Ca(2+) content in NOS1(-/-) cells but had no effect in WT or GSNOR(-/-). Ca(2+) leak and temperature are normally inversely proportional, whereas NOS1 deficiency reverses this effect, increasing leak and elevating reactive oxygen species production because temperature increases. Reduced denitrosylation (GSNOR deficiency) eliminates the temperature dependence of leak. Thus, temperature regulates the balance between NO and reactive oxygen species which in turn has a major effect on SR Ca(2+). © 2014 American Heart Association, Inc.

Effects of temperature on bacterial transport and destruction in bioretention media: field and laboratory evaluations.

PubMed

Zhang, Lan; Seagren, Eric A; Davis, Allen P; Karns, Jeffrey S

2012-06-01

Microbial activities are significantly influenced by temperature. This study investigated the effects of temperature on the capture and destruction of bacteria from urban stormwater runoff in bioretention media using 2-year field evaluations coupled with controlled laboratory column studies. Field data from two bioretention cells show that the concentration of indicator bacteria (fecal coliforms and Escherichia coli) was reduced during most storm events, and that the probability of meeting specific water quality criteria in the discharge was increased. Indicator bacteria concentration in the input flow typically increased with higher daily temperature. Although bacterial removal efficiency was independent of temperature in the field and laboratory, column tests showed that bacterial decay coefficients in conventional bioretention media (CBM) increase exponentially with elevated temperature. Increases in levels of protozoa and heterotrophic bacteria associated with increasing temperature appear to contribute to faster die-off of trapped E. coli in CBM via predation and competition.

Nanoindentation study of bulk zirconium hydrides at elevated temperatures

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

Cinbiz, Mahmut Nedim; Balooch, Mehdi; Hu, Xunxiang

Here, the mechanical properties of zirconium hydrides was studied using nano-indentation technique at a temperature range of 25 – 400 °C. Temperature dependency of reduced elastic modulus and hardness of δ- and ε-zirconium hydrides were obtained by conducting nanoindentation experiments on the bulk hydride samples with independently heating capability of indenter and heating stage. The reduced elastic modulus of δ-zirconium hydride (H/Zr ratio =1.61) decreased from ~113 GPa to ~109 GPa while temperature increased from room temperature to 400°C. For ε-zirconium hydrides (H/Zr ratio=1.79), the reduced elastic modulus decreased from 61 GPa to 54 GPa as temperature increased from roommore » temperature to 300 °C. Whereas, hardness of δ-zirconium hydride significantly decreased from 4.1 GPa to 2.41 GPa when temperature increased from room temperature to 400 °C. Similarly, hardness of ε-zirconium hydride decreased from 3.06 GPa to 2.19 GPa with temperature increase from room temperature to 300°C.« less

Nanoindentation study of bulk zirconium hydrides at elevated temperatures

DOE PAGES

Cinbiz, Mahmut Nedim; Balooch, Mehdi; Hu, Xunxiang; ...

2017-08-02

Here, the mechanical properties of zirconium hydrides was studied using nano-indentation technique at a temperature range of 25 – 400 °C. Temperature dependency of reduced elastic modulus and hardness of δ- and ε-zirconium hydrides were obtained by conducting nanoindentation experiments on the bulk hydride samples with independently heating capability of indenter and heating stage. The reduced elastic modulus of δ-zirconium hydride (H/Zr ratio =1.61) decreased from ~113 GPa to ~109 GPa while temperature increased from room temperature to 400°C. For ε-zirconium hydrides (H/Zr ratio=1.79), the reduced elastic modulus decreased from 61 GPa to 54 GPa as temperature increased from roommore » temperature to 300 °C. Whereas, hardness of δ-zirconium hydride significantly decreased from 4.1 GPa to 2.41 GPa when temperature increased from room temperature to 400 °C. Similarly, hardness of ε-zirconium hydride decreased from 3.06 GPa to 2.19 GPa with temperature increase from room temperature to 300°C.« less

Thermal biology, population fluctuations and implications of temperature extremes for the management of two globally significant insect pests.

PubMed

Nyamukondiwa, Casper; Weldon, Christopher W; Chown, Steven L; le Roux, Peter C; Terblanche, John S

2013-12-01

The link between environmental temperature, physiological processes and population fluctuations is a significant aspect of insect pest management. Here, we explore how thermal biology affects the population abundance of two globally significant pest fruit fly species, Ceratitis capitata (medfly) and C. rosa (Natal fruit fly), including irradiated individuals and those expressing a temperature sensitive lethal (tsl) mutation that are used in the sterile insect technique. Results show that upper and lower lethal temperatures are seldom encountered at the field sites, while critical minimum temperatures for activity and lower developmental thresholds are crossed more frequently. Estimates of abundance revealed that C. capitata are active year-round, but abundance declines markedly during winter. Temporal autocorrelation of average fortnightly trap captures and of development time, estimated from an integrated model to calculate available degree days, show similar seasonal lags suggesting that population increases in early spring occur after sufficient degree-days have accumulated. By contrast, population collapses coincide tightly with increasing frequency of low temperature events that fall below critical minimum temperatures for activity. Individuals of C. capitata expressing the tsl mutation show greater critical thermal maxima and greater longevity under field conditions than reference individuals. Taken together, this evidence suggests that low temperatures limit populations in the Western Cape, South Africa and likely do so elsewhere. Increasing temperature extremes and warming climates generally may extend the season over which these species are active, and could increase abundance. The sterile insect technique may prove profitable as climates change given that laboratory-reared tsl flies have an advantage under warmer conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

County-level analysis of the impact of temperature and population increases on California wildfire data

USGS Publications Warehouse

Baltar, M.; Keeley, Jon E.; Schoenberg, F.P.

2013-01-01

The extent to which the apparent increase in wildfire incidence and burn area in California from 1990 to 2006 is affected by population and temperature increases is examined. Using generalized linear models with random effects, we focus on the estimated impacts of increases in mean daily temperatures and populations in different counties on wildfire in those counties, after essentially controlling for the overall differences between counties in their overall mean temperatures and populations. We find that temperature increase appears to have a significant positive impact on both total burn area and number of observed wildfires. Population growth appears to have a much less pronounced impact on total burn area than do annual temperature increases, and population growth appears to be negatively correlated with the total number of observed wildfires. These effects are especially pronounced in the winter season and in Southern California counties.

Spatiotemporal trends in extreme rainfall and temperature indices over Upper Tapi Basin, India

NASA Astrophysics Data System (ADS)

Sharma, Priyank J.; Loliyana, V. D.; S. R., Resmi; Timbadiya, P. V.; Patel, P. L.

2017-12-01

The flood risk across the globe is intensified due to global warming and subsequent increase in extreme temperature and precipitation. The long-term trends in extreme rainfall (1944-2013) and temperature (1969-2012) indices have been investigated at annual, seasonal, and monthly time scales using nonparametric Mann-Kendall (MK), modified Mann-Kendall (MMK), and Sen's slope estimator tests. The extreme rainfall and temperature indices, recommended by the Expert Team on Climate Change Detection Monitoring Indices (ETCCDMI), have been analyzed at finer spatial scales for trend detection. The results of trend analyses indicate decreasing trend in annual total rainfall, significant decreasing trend in rainy days, and increasing trend in rainfall intensity over the basin. The seasonal rainfall has been found to decrease for all the seasons except postmonsoon, which could affect the rain-fed agriculture in the basin. The 1- and 5-day annual maximum rainfalls exhibit mixed trends, wherein part of the basin experiences increasing trend, while other parts experience a decreasing trend. The increase in dry spells and concurrent decrease in wet spells are also observed over the basin. The extreme temperature indices revealed increasing trends in hottest and coldest days, while decreasing trends in coldest night are found over most parts of the basin. Further, the diurnal temperature range is also found to increase due to warming tendency in maximum temperature (T max) at a faster rate compared to the minimum temperature (T min). The increase in frequency and magnitude of extreme rainfall in the basin has been attributed to the increasing trend in maximum and minimum temperatures, reducing forest cover, rapid pace of urbanization, increase in human population, and thereby increase in the aerosol content in the atmosphere. The findings of the present study would significantly help in sustainable water resource planning, better decision-making for policy framework, and setting up infrastructure against flood disasters in Upper Tapi Basin, India.

Potential Impacts of Climate Change on Stream Water Temperatures Across the United States

NASA Astrophysics Data System (ADS)

Ehsani, N.; Knouft, J.; Ficklin, D. L.

2017-12-01

Analyses of long-term observation data have revealed significant changes in several components of climate and the hydrological cycle over the contiguous United States during the twentieth and early twenty-first century. Mean surface air temperatures have significantly increased in most areas of the country. In addition, water temperatures are increasing in many watersheds across the United States. While there are numerous studies assessing the impact of climate change on air temperatures at regional and global scales, fewer studies have investigated the impacts of climate change on stream water temperatures. Projecting increases in water temperature are particularly important to the conservation of freshwater ecosystems. To achieve better insights into attributes regulating population and community dynamics of aquatic biota at large spatial and temporal scales, we need to establish relationships between environmental heterogeneity and critical biological processes of stream ecosystems at these scales. Increases in stream temperatures caused by the doubling of atmospheric carbon dioxide may result in a significant loss of fish habitat in the United States. Utilization of physically based hydrological-water temperature models is computationally demanding and can be onerous to many researchers who specialize in other disciplines. Using statistical techniques to analyze observational data from 1760 USGS stream temperature gages, our goal is to develop a simple yet accurate method to quantify the impacts of climate warming on stream water temperatures in a way that is practical for aquatic biologists, water and environmental management purposes, and conservation practitioners and policy-makers. Using an ensemble of five global climate models (GCMs), we estimate the potential impacts of climate change on stream temperatures within the contiguous United States based on recent trends. Stream temperatures are projected to increase across the US, but the magnitude of the changes are not expected to be uniform across the region and these relationships are expected to vary from month to month. Combined with expected changes in stream flows, the projected changes in the thermal regimes of streams can fundamentally transform stream habitats and the distribution of biodiversity.

Hemodynamic changes during whole body surface cooling and lower body negative pressure

NASA Technical Reports Server (NTRS)

Raven, P. B.; Pape, G.; Taylor, W. F.; Gaffney, F. A.; Blomqvist, C. G.

1981-01-01

Six young healthy male subjects were studied to evaluate the use of whole body surface cooling (WBSC) as an antiorthostatic intervention. Previous studies have demonstrated that perfusion of an Apollo cooling garment with 16 C water produced a significant increase in stroke volume and decrease in heart rate at rest and during lower body negative pressure (LBNP). However, optimal perfusion temperatures have not been determined. The present study examined the effects of WBSC using perfusion of water at a temperature of 10 C. This perfusion temperature produced a greater decrease in mean skin temperature than water at 16 C (4 C drop compared to 2 C). The hemodynamic effects were also more prominent with 10 C water as shown by the increase in stroke volume of 11% at rest and of 35% during LBNP at -50 torr compared to control measurements at ambient temperature. Heart rates were lowered significantly (8 beats/min) and systolic arterial blood pressure was higher (8 torr). Cooling with 10 C water produced a slight increase in muscle tone, reflected by a small but significant increase (+84 ml/min) in oxygen uptake. These data suggest that WBSC is an effective nonpharmacologic means of controlling preload and deserves further investigation as an antiorthostatic intervention.

Theoretical and experimental study on reabsorption effect and temperature characteristic of a quasi-three-level 946nm Nd:YAG laser

NASA Astrophysics Data System (ADS)

Huang, Jing; Wan, Yuan; Chen, Weibiao

2015-02-01

The influence of temperature and incident pump power on reabsorption loss is theoretically discussed. Temperature characteristic and reabsorption loss rate of a diode-pumped quasi-three-level 946 nm Nd:YAG laser are investigated. Reabsorption effect has a significant impact on laser performance. The results indicate that reabsorption loss increases as the working temperature rises and decreases with the increased incident pump power.

Effect of elevated temperature on soil hydrothermal regimes and growth of wheat crop.

PubMed

Pramanik, P; Chakrabarti, Bidisha; Bhatia, Arti; Singh, S D; Maity, A; Aggarwal, P; Krishnan, P

2018-03-14

An attempt has been made to study the effect of elevated temperature on soil hydrothermal regimes and winter wheat growth under simulated warming in temperature gradient tunnel (TGT). Results showed that bulk density (BDs) of 0, 0.9, and 2.5 °C were significantly different whereas BDs of 2.8 and 3.5 °C were not significantly different. Water filled pore space (WFPS) was maximum at 3.5 °C temperature rise and varied between 43.80 and 98.55%. Soil surface temperature (ST) at different dates of sowing increased with rise in sensor temperature and highest ST was observed at S5 sensors (3.5 °C temperature rise). Temperature and its difference were high for the top soil, and were stable for the deep soil. Photosynthesis rate (μmol CO 2 m -2  s -1 ) of wheat was lower at higher temperature in different growth stages of wheat. In wheat, stomatal conductance declined from 0.67 to 0.44 mol m -2  s -1 with temperature rise. Stomatal conductance decreased with increase in soil temperature and gravimetric soil moisture content (SWC). In TGT, 0 °C temperature rise showed highest root weight density (RWD) (5.95 mg cm -3 ); whereas, 2.8 and 3.5 °C showed lowest RWD (4.90 mg cm -3 ). Harvest index was maximum (0.37) with 0 °C temperature rise, and it decreased with increase in temperature, which indicated that both grain and shoot biomass decreased with increase in temperature. Intensive studies are needed to quantify the soil hydrothermal regimes inside TGT along with the crop growth parameters.

Bone heat generated using conventional implant drills versus piezosurgery unit during apical cortical plate perforation.

PubMed

Lajolo, Carlo; Valente, Nicola Alberto; Romandini, William Giuseppe; Petruzzi, Massimo; Verdugo, Fernando; D'Addona, Antonio

2018-03-09

The apical portion of the implant osteotomy receives less irrigation and cooling during surgical preparation. High bone temperatures, above the critical 10°C threshold, may impair osseointegration, particularly, around dense cortical bone. The aim of this study is to evaluate the apical cortical plate temperature increase with two different devices and pressure loads in a porcine rib ex-vivo model. Twenty-four implant sites were prepared on porcine ribs divided into 4 groups of 6 samples each according to the device used (conventional drill system or piezosurgery) and pressure load applied (1000 g or 1500 g). A rubber dam was used to isolate the apical cortical plate from the cooling effect of irrigation. Temperature variation measurements were taken using an infrared thermometer. The piezosurgery unit was 2 times more likely to increase the osteotomy temperature by 10.0°C (OR = 2; 95% CI = 1.136-3.522; p < 0.05). The average temperature increase was 0.07°C (SD = 0.10) for group 1 (drill system-1,000 g), 0.22°C (SD = 0.26) for group 2 (drill system-1,500 g), 9.18°C (SD = 4.51) for group 3 (piezosurgery-1000 g) and 8.17°C (SD = 6.12) for group 4 (piezosurgery-1,500 g). The piezosurgery site preparation caused significantly higher temperature increase than conventional drills (p < 0.05). There was no statistically significant difference in temperature change between the two pressure loads applied (p = 0.78). Temperature increases exceeded the critical 10°C threshold in half of the samples prepared with the piezoelectric device. Bone overheating using a piezosurgery unit is a potential risk during implant site preparation. The piezosurgical device reached significantly higher temperatures than conventional drilling at the apical cortical portion of the osteotomy. The temperature increase is often higher than the critical 10°C threshold. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Effect of temperature on gene expression in the pearl oyster Pinctada fucata

NASA Astrophysics Data System (ADS)

Liu, Wenguang; Huang, Xiande; Lin, Jianshi; He, Maoxian

2014-06-01

In this study, we examined the effect of elevated temperature on the expression patterns of genes, i.e., nacrein, irr, n16, n19, and hsp70 in the pearl oyster Pinctada fucata. The experiment was carried out at 4 temperatures, i.e., 20°C (ambient, control), 24, 28°C, and 32°C. The expression levels of target genes in P. fucata were assayed at 0, 6, 24, 48, and 96 h via real-time polymerase chain reaction. Results showed that the expression levels of nacrein and irr had no significant variations among different time points below 28°C, but significantly increased over time at 32°C. The expression levels of n16 and n19 did not change markedly at 20°C. The former increased significantly at 6 h and 24 h while the latter substantially decreased during 6-96 h at 24, 28 and 32°C. Among different temperatures, the level of n16 was significantly lower at 20°C than at other temperatures during 6-96 h, and the level of n19 significantly varied among different temperatures at 48 h and 96 h. The expression level of hsp70 was significantly higher at 32°C than at 20, 24 and 28°C at 24 h. These results demonstrated that elevated temperature impacted the physiological processes of P. fucata and potentially influenced its adaptability to thermal stress.

Intramuscular temperature modulates glutamate-evoked masseter muscle pain intensity in humans.

PubMed

Sato, Hitoshi; Castrillon, Eduardo E; Cairns, Brian E; Bendixen, Karina H; Wang, Kelun; Nakagawa, Taneaki; Wajima, Koichi; Svensson, Peter

2015-01-01

To determine whether glutamate-evoked jaw muscle pain is altered by the temperature of the solution injected. Sixteen healthy volunteers participated and received injections of hot (48°C), neutral (36°C), or cold (3°C) solutions (0.5 mL) of glutamate or isotonic saline into the masseter muscle. Pain intensity was assessed with an electronic visual analog scale (eVAS). Numeric rating scale (NRS) scores of unpleasantness and temperature perception, pain-drawing areas, and pressure pain thresholds (PPTs) were also measured. Participants filled out the McGill Pain Questionnaire (MPQ). Two-way or three-way repeated measures ANOVA were used for data analyses. Injection of hot glutamate and cold glutamate solutions significantly increased and decreased, respectively, the peak pain intensity compared with injection of neutral glutamate solution. The duration of glutamate-evoked pain was significantly longer when hot glutamate was injected than when cold glutamate was injected. No significant effect of temperature on pain intensity was observed when isotonic saline was injected. No effect of solution temperature was detected on unpleasantness, heat perception, cold perception, area of pain drawings, or PPTs. There was a significantly greater use of the "numb" term in the MPQ to describe the injection of cold solutions compared to the injection of both neutral and hot solutions. Glutamate-evoked jaw muscle pain was significantly altered by the temperature of the injection solution. Although temperature perception in the jaw muscle is poor, pain intensity is increased when the muscle tissue temperature is elevated.

Effect of feed composition, moisture content and extrusion temperature on extrudate characteristics of yam-corn-rice based snack food.

PubMed

Seth, Dibyakanta; Badwaik, Laxmikant S; Ganapathy, Vijayalakshmi

2015-03-01

Blends of yam, rice and corn flour were processed in a twin-screw extruder. Effects of yam flour (10-40 %), feed moisture content (12-24 %) and extruder barrel temperature (100-140 °C) on the characteristics of the dried extrudates was investigated using a statistical technique response surface methodology (RSM). Radial expansion ratio differed significantly (p ≤ 0.05) with change in all the independent variables. Highest expansion (3.97) was found at lowest moisture content (12 %) and highest barrel temperature (140 °C). Increased yam flour level decreased the expansion ratio significantly. Water absorption index (WAI) increased significantly with increase of all variables. However, water solubility index (WSI) did not change with change in yam flour percent. Hardness of extrudates that varied from 3.86 to 6.94 N was positively correlated with yam flour level and feed moisture content, however it decreased significantly (p ≤ 0.001) with increase of barrel temperature. Yam percent of 15.75 with feed moisture and barrel temperature at 12.00 % and 140 °C respectively gave an optimized product of high desirability (> 0.90) with optimum responses of 3.29 expansion ratio, 5.64 g/g dry solid water absorption index, 30.39 % water solubility index and 3.86 N hardness. The predicted values registered non-significant (p < 0.10) differences from the experimental results. Further study would include the sensory properties enhancement of extruded snacks and little emphasis on the chemistry of interaction between different components.

Interaction between Soil Moisture and Air Temperature in the Mississippi River Basin

EPA Science Inventory

Increasing air temperatures are expected to continue in the future. The relation between soil moisture and near surface air temperature is significant for climate change and climate extremes. Evaluation of the relations between soil moisture and temperature was performed by devel...

Effects of tip-substrate gap, deposition temperature, holding time, and pull-off velocity on dip-pen lithography investigated using molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Wu, Cheng-Da; Fang, Te-Hua; Lin, Jen-Fin

2012-05-01

The process parameters in the dip-pen nanolithography process, including tip-substrate gap, deposition temperature, holding time, and pull-off velocity are evaluated in terms of the mechanism of molecular transference, alkanethiol meniscus characteristic, surface adsorbed energy, and pattern formation using molecular dynamics simulations. The simulation results clearly show that the optimum deposition occurs at a smaller tip-substrate gap, a slower pull-off velocity, a higher temperature, and a longer holding time. The pattern area increases with decreasing tip-substrate gap and increasing deposition temperature and holding time. With an increase in deposition temperature, the molecular transfer ability significantly increases. Pattern height is a function of meniscus length. When the pull-off velocity is decreased, the pattern height increases. The height of the neck in meniscus decreases and the neck width increases with holding time. Meniscus size increases with increasing deposition temperature and holding time.

Influence of pyrolysis temperature on properties and environmental safety of heavy metals in biochars derived from municipal sewage sludge.

PubMed

Jin, Junwei; Li, Yanan; Zhang, Jianyun; Wu, Shengchun; Cao, Yucheng; Liang, Peng; Zhang, Jin; Wong, Ming Hung; Wang, Minyan; Shan, Shengdao; Christie, Peter

2016-12-15

Dried raw sludge was pyrolyzed at temperatures ranging from 400 to 600°C at the increase of 50°C intervals to investigate the influence of pyrolysis temperature on properties and environmental safety of heavy metals in biochar derived from municipal sewage sludge. The sludge biochar yield decreased significantly with increasing pyrolysis temperature but the pH, ash content and specific surface area increased. Conversion of sludge to biochar markedly decreased the H/C and N/C ratios. FT-IR analysis confirmed a dramatic depletion of H and N and a higher degree of aromatic condensation in process of biochar formation at higher temperatures. The total concentrations of Cu, Zn, Pb, Cr, Mn, and Ni increased with conversion of sludge to biochar and increasing pyrolysis temperature. However, using BCR sequential extraction and analysis, it was found that most of the heavy metals existed in the oxizable and residual forms after pyrolysis, especially at 600°C, resulting in a significant reduction in their bioavailability, leading to a very low environmental risk of the biochar. The present study indicates pyrolysis is a promising sludge treatment method for heavy metals immobilization in biochar, and highlights the potential to minimize the harmful effects of biochar by controlling pyrolysis temperature. Copyright © 2016 Elsevier B.V. All rights reserved.

Climate change summary

Treesearch

Steve McNulty; Jennifer Moore Myers; Peter Caldwell; Ge Sun

2013-01-01

Key FindingsSince 1960, all but two southern capital cities (Montgomery, AL, and Oklahoma City, OK) have experienced a statistically significant increase in average annual temperature (approximately 0.016° C), but none has experienced significant trends in precipitation.The South is forecasted to experience warmer temperatures...

Infectious Disease in a Warming World: How Weather Influenced West Nile Virus in the United States (2001–2005)

PubMed Central

Soverow, Jonathan E.; Wellenius, Gregory A.; Fisman, David N.; Mittleman, Murray A.

2009-01-01

Background The effects of weather on West Nile virus (WNV) mosquito populations in the United States have been widely reported, but few studies assess their overall impact on transmission to humans. Objectives We investigated meteorologic conditions associated with reported human WNV cases in the United States. Methods We conducted a case–crossover study to assess 16,298 human WNV cases reported to the Centers for Disease Control and Prevention from 2001 to 2005. The primary outcome measures were the incidence rate ratio of disease occurrence associated with mean weekly maximum temperature, cumulative weekly temperature, mean weekly dew point temperature, cumulative weekly precipitation, and the presence of ≥ 1 day of heavy rainfall (≥ 50 mm) during the month prior to symptom onset. Results Increasing weekly maximum temperature and weekly cumulative temperature were similarly and significantly associated with a 35–83% higher incidence of reported WNV infection over the next month. An increase in mean weekly dew point temperature was significantly associated with a 9–38% higher incidence over the subsequent 3 weeks. The presence of at least 1 day of heavy rainfall within a week was associated with a 29–66% higher incidence during the same week and over the subsequent 2 weeks. A 20-mm increase in cumulative weekly precipitation was significantly associated with a 4–8% increase in incidence of reported WNV infection over the subsequent 2 weeks. Conclusions Warmer temperatures, elevated humidity, and heavy precipitation increased the rate of human WNV infection in the United States independent of season and each others’ effects. PMID:19654911

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

PubMed

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

2015-10-05

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

The effects of thermal and high-CO2 stresses on the metabolism and surrounding microenvironment of the coral Galaxea fascicularis.

PubMed

Agostini, Sylvain; Fujimura, Hiroyuki; Higuchi, Tomihiko; Yuyama, Ikuko; Casareto, Beatriz E; Suzuki, Yoshimi; Nakano, Yoshikatsu

2013-08-01

The effects of elevated temperature and high pCO2 on the metabolism of Galaxea fascicularis were studied with oxygen and pH microsensors. Photosynthesis and respiration rates were evaluated from the oxygen fluxes from and to the coral polyps. High-temperature alone lowered both photosynthetic and respiration rates. High pCO2 alone did not significantly affect either photosynthesis or respiration rates. Under a combination of high-temperature and high-CO2, the photosynthetic rate increased to values close to those of the controls. The same pH in the diffusion boundary layer was observed under light in both (400 and 750 ppm) CO2 treatments, but decreased significantly in the dark as a result of increased CO2. The ATP contents decreased with increasing temperature. The effects of temperature on the metabolism of corals were stronger than the effects of increased CO2. The effects of acidification were minimal without combined temperature stress. However, acidification combined with higher temperature may affect coral metabolism due to the amplification of diel variations in the microenvironment surrounding the coral and the decrease in ATP contents. Copyright © 2013 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Effect of temperature on compact layer of Pt electrode in PEMFCs by first-principles molecular dynamics calculations

NASA Astrophysics Data System (ADS)

He, Yang; Chen, Changfeng; Yu, Haobo; Lu, Guiwu

2017-01-01

Formation of the double-layer electric field and capacitance of the water-metal interface is of significant interest in physicochemical processes. In this study, we perform first- principles molecular dynamics simulations on the water/Pt(111) interface to investigate the temperature dependence of the compact layer electric field and capacitance based on the calculated charge densities. On the Pt (111) surface, water molecules form ice-like structures that exhibit more disorder along the height direction with increasing temperature. The Osbnd H bonds of more water molecules point toward the Pt surface to form Ptsbnd H covalent bonds with increasing temperature, which weaken the corresponding Osbnd H bonds. In addition, our calculated capacitance at 300 K is 15.2 mF/cm2, which is in good agreement with the experimental results. As the temperature increases from 10 to 450 K, the field strength and capacitance of the compact layer on Pt (111) first increase and then decrease slightly, which is significant for understanding the water/Pt interface from atomic level.

Forest clearfelling effects on dissolved oxygen and metabolism in peatland streams.

PubMed

O'Driscoll, Connie; O'Connor, Mark; Asam, Zaki-Ul-Zaman; de Eyto, Elvira; Brown, Lee E; Xiao, Liwen

2016-01-15

Peatlands cover ∼3% of the world's landmass and large expanses have been altered significantly as a consequence of land use change. Forestry activities are a key pressure on these catchments increasing suspended sediment and nutrient export to receiving waters. The aim of this study was to investigate stream dissolved oxygen (DO) and metabolic activity response following clearfelling of a 39-year-old lodgepole pine and Sitka spruce forestry in an upland peat catchment. Significant effects of clearfelling on water temperature, flows, DO and stream metabolic (photosynthesis, respiration) rates were revealed. Stream temperature and discharge significantly increased in the study stream following clearfelling. Instream ecosystem respiration increased significantly following clearfelling, indicating an increase in the net consumption of organic carbon. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nitrogen Can Alleviate the Inhibition of Photosynthesis Caused by High Temperature Stress under Both Steady-State and Flecked Irradiance.

PubMed

Huang, Guanjun; Zhang, Qiangqiang; Wei, Xinghai; Peng, Shaobing; Li, Yong

2017-01-01

Nitrogen is one of the most important elements for plants and is closely related to photosynthesis. High temperature stress significantly inhibits photosynthesis under both steady-state and flecked irradiance. However, it is not known whether nitrogen can affect the decrease in photosynthesis caused by high temperature, especially under flecked irradiance. In the present study, a pot experiment was conducted under two nitrogen (N) supplies with rice plants, and the steady-state and dynamic photosynthesis rates were measured under 28 and 40°C. High temperature significantly increased leaf hydraulic conductance ( K leaf ) under high N supply (HN) but not under low N supply (LN). The increased K leaf maintained a constant leaf water potential (Ψ leaf ) and steady-state stomatal conductance ( g s,sat ) under HN, while the Ψ leaf and g s,sat significantly decreased under high temperature in LN conditions. This resulted in a more severe decrease in steady-state photosynthesis ( A sat ) under high temperature in the LN conditions. After shifting from low to high light, high temperature significantly delayed the recovery of photosynthesis, which resulted in more carbon loss under flecked irradiance. These effects were obtained under HN to a lesser extent than under LN supply. Therefore, it is concluded that nitrogen can alleviate the inhibition of photosynthesis caused by high temperature stress under both steady-state and flecked irradiance.

Effect of regional climate warming on the phenology of butterflies in boreal forests in Manitoba, Canada.

PubMed

Westwood, A R; Blair, D

2010-08-01

We examined the effect of regional climate warming on the phenology of butterfly species in boreal forest ecosystems in Manitoba, Canada. For the period 1971-2004, the mean monthly temperatures in January, September, and December increased significantly, as did the mean temperatures for several concurrent monthly periods. The mean annual temperature increased ≈ 0.05°C/yr over the study period. The annual number of frost-free days and degree-day accumulations increased as well. We measured the response of 19 common butterfly species to these temperature changes with the date of first appearance, week of peak abundance, and the length of flight period over the 33-yr period of 1972-2004. Although adult butterfly response was variable for spring and summer months, 13 of 19 species showed a significant (P < 0.05) increase in flight period extending longer into the autumn. Flight period extensions increased by 31.5 ± 13.9 (SD) d over the study period for 13 butterfly species significantly affected by the warming trend. The early autumn and winter months warmed significantly, and butterflies seem to be responding to this warming trend with a change in the length of certain life stages. Two species, Junonia coenia and Euphydryas phaeton, increased their northerly ranges by ≈ 150 and 70 km, respectively. Warmer autumns and winters may be providing opportunities for range extensions of more southerly butterfly species held at bay by past climatic conditions.

Emission of phthalates and phthalate alternatives from vinyl flooring and crib mattress covers: the influence of temperature.

PubMed

Liang, Yirui; Xu, Ying

2014-12-16

Emissions of phthalates and phthalate alternatives from vinyl flooring and crib mattress covers were measured in a specially designed chamber. The gas-phase concentrations versus time were measured at four different temperatures, that is, 25, 36, 45, and 55 °C. The key parameter that controls the emissions (y0, gas-phase concentration in equilibrium with the material phase) was determined, and the emissions were found to increase significantly with increasing temperature. Both the material-phase concentration (C0) and the chemical vapor pressure (Vp) were found to have great influence on the value of y0. The measured ratios of C0 to y0 were exponentially proportional to the reciprocal of temperature, in agreement with the van't Hoff equation. A emission model was validated at different temperatures, with excellent agreement between model calculations and chamber observations. In residential homes, an increase in the temperature from 25 to 35 °C can elevate the gas-phase concentration of phthalates by more than a factor of 10, but the total airborne concentration may not increase that much for less volatile compounds. In infant sleep microenvironments, an increase in the temperature of mattress can cause a significant increase in emission of phthalates from the mattress cover and make the concentration in the infant's breathing zone about four times higher than that in the bulk room air, resulting in potentially high exposure.

Temperature sensitivity of soil organic carbon mineralization along an elevation gradient in the Wuyi Mountains, China.

PubMed

Wang, Guobing; Zhou, Yan; Xu, Xia; Ruan, Honghua; Wang, Jiashe

2013-01-01

Soil organic carbon (SOC) actively participates in the global carbon (C) cycle. Despite much research, however, our understanding of the temperature sensitivity of soil organic carbon (SOC) mineralization is still very limited. To investigate the responses of SOC mineralization to temperature, we sampled surface soils (0-10 cm) from evergreen broad-leaf forest (EBF), coniferous forest (CF), sub-alpine dwarf forest (SDF), and alpine meadow (AM) along an elevational gradient in the Wuyi Mountains, China. The soil samples were incubated at 5, 15, 25, and 35°C with constant soil moisture for 360 days. The temperature sensitivity of SOC mineralization (Q(10)) was calculated by comparing the time needed to mineralize the same amount of C at any two adjacent incubation temperatures. Results showed that the rates of SOC mineralization and the cumulative SOC mineralized during the entire incubation significantly increased with increasing incubation temperatures across the four sites. With the increasing extent of SOC being mineralized (increasing incubation time), the Q(10) values increased. Moreover, we found that both the elevational gradient and incubation temperature intervals significantly impacted Q(10) values. Q(10) values of the labile and recalcitrant organic C linearly increased with elevation. For the 5-15, 15-25, and 25-35°C intervals, surprisingly, the overall Q(10) values for the labile C did not decrease as the recalcitrant C did. Generally, our results suggest that subtropical forest soils may release more carbon than expected in a warmer climate.

SPH investigation of the thermal effects on the fluid mixing in a microchannel with rotating stirrers

NASA Astrophysics Data System (ADS)

Shamsoddini, Rahim

2018-04-01

An incompressible smoothed particle hydrodynamics algorithm is proposed to model and investigate the thermal effect on the mixing rate of an active micromixer in which the rotating stirrers enhance the mixing rate. In liquids, mass diffusion increases with increasing temperature, while viscosity decreases; so, the local Schmidt number decreases considerably with increasing temperature. The present study investigates the effect of wall temperature on mixing rate with an improved SPH method. The robust SPH method used in the present work is equipped with a shifting algorithm and renormalization tensors. By introducing this new algorithm, the several mass, momentum, energy, and concentration equations are solved. The results, discussed for different temperature ratios, show that mixing rate increases significantly with increased temperature ratio.

Continuous selection pressure to improve temperature acclimation of Tisochrysis lutea

PubMed Central

Grimaud, Ghjuvan; Rumin, Judith; Bougaran, Gaël; Talec, Amélie; Gachelin, Manon; Boutoute, Marc; Pruvost, Eric; Bernard, Olivier; Sciandra, Antoine

2017-01-01

Temperature plays a key role in outdoor industrial cultivation of microalgae. Improving the thermal tolerance of microalgae to both daily and seasonal temperature fluctuations can thus contribute to increase their annual productivity. A long term selection experiment was carried out to increase the thermal niche (temperature range for which the growth is possible) of a neutral lipid overproducing strain of Tisochrysis lutea. The experimental protocol consisted to submit cells to daily variations of temperature for 7 months. The stress intensity, defined as the amplitude of daily temperature variations, was progressively increased along successive selection cycles. Only the amplitude of the temperature variations were increased, the daily average temperature was kept constant along the experiment. This protocol resulted in a thermal niche increase by 3°C (+16.5%), with an enhancement by 9% of the maximal growth rate. The selection process also affected T. lutea physiology, with a feature generally observed for ‘cold-temperature’ type of adaptation. The amount of total and neutral lipids was significantly increased, and eventually productivity was increased by 34%. This seven month selection experiment, carried out in a highly dynamic environment, challenges some of the hypotheses classically advanced to explain the temperature response of microalgae. PMID:28902878

Advanced Power Electronics Components

NASA Technical Reports Server (NTRS)

Schwarze, Gene E.

2004-01-01

This paper will give a description and status of the Advanced Power Electronics Materials and Components Technology program being conducted by the NASA Glenn Research Center for future aerospace power applications. The focus of this research program is on the following: 1) New and/or significantly improved dielectric materials for the development of power capacitors with increased volumetric efficiency, energy density, and operating temperature. Materials being investigated include nanocrystalline and composite ceramic dielectrics and diamond-like carbon films; 2) New and/or significantly improved high frequency, high temperature, low loss soft magnetic materials for the development of transformers/inductors with increased power/energy density, electrical efficiency, and operating temperature. Materials being investigated include nanocrystalline and nanocomposite soft magnetic materials; 3) Packaged high temperature, high power density, high voltage, and low loss SiC diodes and switches. Development of high quality 4H- and 6H- SiC atomically smooth substrates to significantly improve device performance is a major emphasis of the SiC materials program; 4) Demonstration of high temperature (> 200 C) circuits using the components developed above.

Spatial Correlations of Anomaly Time Series of AIRS Version-6 Land Surface Skin Temperatures with the Nino-4 Index

NASA Technical Reports Server (NTRS)

Susskind, Joel; Lee, Jae N.; Iredell, Lena

2013-01-01

The AIRS Science Team Version-6 data set is a valuable resource for meteorological studies. Quality Controlled earth's surface skin temperatures are produced on a 45 km x 45 km spatial scale under most cloud cover conditions. The same retrieval algorithm is used for all surface types under all conditions. This study used eleven years of AIRS monthly mean surface skin temperature and cloud cover products to show that land surface skin temperatures have decreased significantly in some areas and increased significantly in other areas over the period September 2002 through August 2013. These changes occurred primarily at 1:30 PM but not at 1:30 AM. Cooling land areas contained corresponding increases in cloud cover over this time period, with the reverse being true for warming land areas. The cloud cover anomaly patterns for a given month are affected significantly by El Nino/La Nina activity, and anomalies in cloud cover are a driving force behind anomalies in land surface skin temperature.

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

PubMed Central

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

2015-01-01

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

Is Kinesio Taping to Generate Skin Convolutions Effective for Increasing Local Blood Circulation?

PubMed Central

Yang, Jae-Man; Lee, Jung-Hoon

2018-01-01

Background It is unclear whether traditional application of Kinesio taping, which produces wrinkles in the skin, is effective for improving blood circulation. This study investigated local skin temperature changes after the application of an elastic therapeutic tape using convolution and non-convolution taping methods (CTM/NCTM). Material/Methods Twenty-eight pain-free men underwent CTM and NCTM randomly applied to the right and left sides of the lower back. Using infrared thermography, skin temperature was measured before, immediately after application, 5 min later, 15 min later, and after the removal of the tape. Results Both CTM and NCTM showed a slight, but significant, decrease in skin temperature for up to 5 min. The skin temperature at 15 min and after the removal of the tape was not significantly different from the initial temperature for CTM and NCTM. There were also no significant differences in the skin temperatures between CTM and NCTM. Conclusions Our findings do not support a therapeutic effect of wrinkling the skin with elastic tape application as a technique to increase local blood flow. PMID:29332101

Is Kinesio Taping to Generate Skin Convolutions Effective for Increasing Local Blood Circulation?

PubMed

Yang, Jae-Man; Lee, Jung-Hoon

2018-01-14

BACKGROUND It is unclear whether traditional application of Kinesio taping, which produces wrinkles in the skin, is effective for improving blood circulation. This study investigated local skin temperature changes after the application of an elastic therapeutic tape using convolution and non-convolution taping methods (CTM/NCTM). MATERIAL AND METHODS Twenty-eight pain-free men underwent CTM and NCTM randomly applied to the right and left sides of the lower back. Using infrared thermography, skin temperature was measured before, immediately after application, 5 min later, 15 min later, and after the removal of the tape. RESULTS Both CTM and NCTM showed a slight, but significant, decrease in skin temperature for up to 5 min. The skin temperature at 15 min and after the removal of the tape was not significantly different from the initial temperature for CTM and NCTM. There were also no significant differences in the skin temperatures between CTM and NCTM. CONCLUSIONS Our findings do not support a therapeutic effect of wrinkling the skin with elastic tape application as a technique to increase local blood flow.

Pulpal temperature increase with high-speed handpiece, Er:YAG laser and ultrasound tips.

PubMed

Mollica, Fernanda Brandão; Camargo, Fernanda Pelogia; Zamboni, Sandra Costa; Pereira, Sarina Maciel Braga; Teixeira, Symone Cristina; Nogueira, Lafayette

2008-01-01

The aim of this study was to compare intrapulpal temperature increase produced by high-speed handpiece, Er:YAG laser and CVDentus ultrasound tips during cavity preparation. Thirty bovine mandibular incisors with an enamel/dentin thickness of 4 mm at buccal surface had their roots amputated and were allocated to the following groups (n=10): Group I- high-speed handpiece; Group II- noncontact Er:YAG laser (250 mJ/4 Hz); and Group III- CVDentus ultrasouns tips. All devices were used with water cooling. Class V cavities were prepared to a depth of 3.5 mm, measured with a periodontal probe. A type T thermocouple was placed inside the pulp chamber to determine the temperature increase (degrees C), which was recorded by a data acquisition system ADS 2000 IP (Lynx Technology) linked to a notebook computer. Data were analyzed statistically by one-way ANOVA and Tukey's test (p=0.05). The mean temperature rises were: 1.10 degrees C (+/-0.56) for Group I, 0.84 degrees C (+/-0.55) for Group II, and 3.00 degrees C (+/- 1.34) for Group III. There were no statistically significant differences (p>0.05) between Groups I and II, but both of them differed significantly from Group III (p<0.05). In conclusion, the use of Er:YAG laser and high-speed handpiece for cavity preparation resulted in similar temperature increase. Although ultrasound tips generated significantly higher intrapulpal temperature increase, it remained below the critical value of 5.5 degrees C and may be considered safe for use.

Subarctic Lake Sediment Microbial Community Contributions to Methane Emission Patterns

NASA Astrophysics Data System (ADS)

Emerson, J. B.; Varner, R. K.; Parks, D.; Wik, M.; Neumann, R.; Johnson, J. E.; Singleton, C. M.; Woodcroft, B. J.; Tollerson, R., II; Owusu-Dommey, A.; Binder, M.; Freitas, N. L.; Crill, P. M.; Saleska, S. R.; Tyson, G. W.; Rich, V. I.

2017-12-01

Northern post-glacial lakes have recently been identified as a significant and increasing source of carbon to the atmosphere, largely through ebullition (bubbling) of microbially produced methane from the sediments. Ebullitive methane flux has been shown to correlate significantly with sediment surface temperatures, suggesting that solar radiation is the primary driver of methane emissions from these lakes. However, the slope of this relationship (i.e., the extent to which increasing temperature increases ebullitive methane emissions) differs spatially, both within and among lakes. As microbes are responsible for both methane generation and removal in lakes, we hypothesized that microbial communities—previously uncharacterized in post-glacial lake sediments—could be contributing to spatiotemporal differences in methane emission responses to temperature. We compared methane emission data with sediment microbial (metagenomic and amplicon), isotopic, and geochemical characterizations across two post-glacial lakes in Northern Sweden. With increasing temperatures, the increase in methane emissions was greater in lake middles (deeper water) than lake edges (shallower water), consistent with higher abundances of methanogens in sediments from lake middles than edges, along with significant differences in microbial community composition between these regions. Using sparse partial least squares statistical modeling, microbial abundances (including the abundances of methane-cycling microorganisms and of reconstructed population genomes, e.g., from Planctomycetes, Thermoplasmatales, and Candidate Phylum Aminicenantes) were better predictors of porewater methane concentrations than abiotic variables. These results suggest that, although temperature controls methane emissions, microbial community composition and function may drive the rate and magnitude of this temperature response in subarctic post-glacial lakes.

Root-zone temperatures affect phenology of bud break, flower cluster development, shoot extension growth and gas exchange of 'Braeburn' (Malus domestica) apple trees.

PubMed

Greer, Dennis H; Wünsche, Jens N; Norling, Cara L; Wiggins, Harry N

2006-01-01

We investigated the effects of root-zone temperature on bud break, flowering, shoot growth and gas exchange of potted mature apple (Malus domestica (Borkh.)) trees with undisturbed roots. Soil respiration was also determined. Potted 'Braeburn' apple trees on M.9 rootstock were grown for 70 days in a constant day/night temperature regime (25/18 degrees C) and one of three constant root-zone temperatures (7, 15 and 25 degrees C). Both the proportion and timing of bud break were significantly enhanced as root-zone temperature increased. Rate of floral cluster opening was also markedly increased with increasing root-zone temperature. Shoot length increased but shoot girth growth declined as root-zone temperatures increased. Soil respiration and leaf photosynthesis generally increased as root-zone temperatures increased. Results indicate that apple trees growing in regions where root zone temperatures are < or = 15 degrees C have delayed bud break and up to 20% fewer clusters than apple trees exposed to root zone temperatures of > or = 15 degrees C. The effect of root-zone temperature on shoot performance may be mediated through the mobilization of root reserves, although the role of phytohormones cannot be discounted. Variation in leaf photosynthesis across the temperature treatments was inadequately explained by stomatal conductance. Given that root growth increases with increasing temperature, changes in sink activity induced by the root-zone temperature treatments provide a possible explanation for the non-stomatal effect on photosynthesis. Irrespective of underlying mechanisms, root-zone temperatures influence bud break and flowering in apple trees.

A role for the thermal environment in defining co-stimulation requirements for CD4+ T cell activation

PubMed Central

Zynda, Evan R; Grimm, Melissa J; Yuan, Min; Zhong, Lingwen; Mace, Thomas A; Capitano, Maegan; Ostberg, Julie R; Lee, Kelvin P; Pralle, Arnd; Repasky, Elizabeth A

2015-01-01

Maintenance of normal core body temperature is vigorously defended by long conserved, neurovascular homeostatic mechanisms that assist in heat dissipation during prolonged, heat generating exercise or exposure to warm environments. Moreover, during febrile episodes, body temperature can be significantly elevated for at least several hours at a time. Thus, as blood cells circulate throughout the body, physiologically relevant variations in surrounding tissue temperature can occur; moreover, shifts in core temperature occur during daily circadian cycles. This study has addressed the fundamental question of whether the threshold of stimulation needed to activate lymphocytes is influenced by temperature increases associated with physiologically relevant increases in temperature. We report that the need for co-stimulation of CD4+ T cells via CD28 ligation for the production of IL-2 is significantly reduced when cells are exposed to fever-range temperature. Moreover, even in the presence of sufficient CD28 ligation, provision of extra heat further increases IL-2 production. Additional in vivo and in vitro data (using both thermal and chemical modulation of membrane fluidity) support the hypothesis that the mechanism by which temperature modulates co-stimulation is linked to increases in membrane fluidity and membrane macromolecular clustering in the plasma membrane. Thermally-regulated changes in plasma membrane organization in response to physiological increases in temperature may assist in the geographical control of lymphocyte activation, i.e., stimulating activation in lymph nodes rather than in cooler surface regions, and further, may temporarily and reversibly enable CD4+ T cells to become more quickly and easily activated during times of infection during fever. PMID:26131730

Differential impact of flow and mouth leak on oropharyngeal humidification during high-flow nasal cannula: a neonatal bench study.

PubMed

Ullrich, Tim Leon; Czernik, Christoph; Bührer, Christoph; Schmalisch, Gerd; Fischer, Hendrik Stefan

2018-06-01

Heated humidification is paramount during neonatal high-flow nasal cannula (HFNC) therapy. However, there is little knowledge about the influence of flow rate and mouth leak on oropharyngeal humidification and temperature. The effect of the Optiflow HFNC on oropharyngeal gas conditioning was investigated at flow rates of 4, 6 and 8 L min -1 with and without mouth leak in a bench model simulating physiological oropharyngeal air conditions during spontaneous breathing. Temperature and absolute humidity (AH) were measured using a digital thermo-hygrosensor. Without mouth leak, oropharyngeal temperature and AH increased significantly with increasing flow (P < 0.001). Mouth leak did not affect this increase up to 6 L min -1 , but at 8 L min -1 , temperature and AH plateaued, and the effect of mouth leak became statistically significant (P < 0.001). Mouth leak during HFNC had a negative impact on oropharyngeal gas conditioning when high flows were applied. However, temperature and AH always remained clinically acceptable.

Effects of increased temperatures on Gammarus fossarum under the influence of copper sulphate.

PubMed

Schmidlin, Lara; von Fumetti, Stefanie; Nagel, Peter

2015-03-01

The specialised fauna of freshwater springs will have to cope with a possible temperature rise owing to Global Change. It is affected additionally by contamination of the water with xenobiotics from human activities in the surrounding landscape. We assessed the combined effects of temperature increase and exposure to toxins in laboratory experiments by using copper sulphate as a model substance and Gammarus fossarum Koch, 1835, as the model organism. This amphipod is a common representative of the European spring fauna and copper ions are widespread contaminants, mainly from agricultural practice. The experiments were conducted in boxes placed in flow channels and the water temperatures were varied. The gammarids were fed with conditioned beech leaf discs. The feeding activity of the amphipods was quantified on the level of the organism; and the respiratory electron transport system (ETS) assay was conducted in order to determine changes on the cellular level in the test organisms. The results show that the feeding activity increased slightly with higher water temperature. The sub-lethal copper dose had no significant effect other than a trend towards lower feeding activity. The ETS activity was significantly higher at the higher water temperatures, and the copper ions significantly lowered the ETS activity of the organisms. The combination of the two methods was useful when testing for combined effects of environmental changes and pollutants on a species. From the results one can reasonably infer a higher risk of adverse effects with increase in water temperature and exposure to a particular heavy metal.

Influence of High Temperature Treatment on Mechanical Behavior of a Coarse-grained Marble

NASA Astrophysics Data System (ADS)

Rong, G.; Peng, J.; Jiang, M.

2017-12-01

High temperature has a significant influence on the physical and mechanical behavior of rocks. With increasing geotechnical engineering structures concerning with high temperature problems such as boreholes for oil or gas production, underground caverns for storage of radioactive waste, and deep wells for injection of carbon dioxides, etc., it is important to study the influence of temperature on the physical and mechanical properties of rocks. This paper experimentally investigates the triaxial compressive properties of a coarse-grained marble after exposure to different high temperatures. The rock specimens were first heated to a predetermined temperature (200, 400, and 600 oC) and then cooled down to room temperature. Triaxial compression tests on these heat-treated specimens subjected to different confining pressures (i.e., 0, 5, 10, 15, 20, 25, 30, 35, and 40 MPa) were then conducted. Triaxial compression tests on rock specimens with no heat treatment were also conducted for comparison. The results show that the high temperature treatment has a significant influence on the microstructure, porosity, P-wave velocity, stress-strain relation, strength and deformation parameters, and failure mode of the tested rock. As the treatment temperature gradually increases, the porosity slightly increases and the P-wave velocity dramatically decreases. Microscopic observation on thin sections reveals that many micro-cracks will be generated inside the rock specimen after high temperature treatment. The rock strength and Young's modulus show a decreasing trend with increase of the treatment temperature. The ductility of the rock is generally enhanced as the treatment temperature increases. In general, the high temperature treatment weakens the performance of the tested rock. Finally, a degradation parameter is defined and a strength degradation model is proposed to characterize the strength behavior of heat-treated rocks. The results in this study provide useful data for evaluation of rock properties in high temperature condition.

Metabolic rates of benthic deep-sea decapod crustaceans decline with increasing depth primarily due to the decline in temperature

NASA Astrophysics Data System (ADS)

Childress, J. J.; Cowles, D. L.; Favuzzi, J. A.; Mickel, T. J.

1990-06-01

The oxygen consumption rates of 11 species of benthic deep-sea decapod crustaceans were measured at a variety of temperatures to test the hypothesis that the metabolic rates of benthic crustaceans decline with increasing depth of occurrence only to the extent explained by the decline in temperature with depth. The species were captured at depths between 150 and 2000m off Southern California using an epibenthic beam trawl equipped with a thermally protecting cod-end to bring the animals to the surface uncontaminated by sediment and at the depth temperature. The data, combined with those for six species of shallower-living crustaceans from California waters, showed a significant decline in oxygen consumption rate with increased species' depths of occurrence, when the measurements were made at temperatures appropriate to each species' depth range. There was no significant relation between wet weight and depth of occurrence in these species. When the data were adjusted to 10°C using a moderate temperature effect factor (corresponding to Q10 values of 2-2.3 depending on the species and temperature range), the significant relationship between oxygen consumption rate and depth was lost, indicating that the observed decline with depth was due to the decline in temperature with depth. When the relationship between metabolic rate and depth of occurrence for the most active (carideans and penaeid) species were compared (ANCOVA) with that for the rest of the species, the active species had significantly higher rates. By combining this data set with data from the literature for a wide variety of shallow-living benthic decapod crustaceans, it was possible to create a data set of 35 species in which the effects of temperature, minimum depth of occurrence and body mass could be separated by multiple linear regression. This demonstrated highly significant effects of size and temperature, but no significant effect of depth for the entire data set and for the data set excluding penaeids and carideans. In contrast, the carideans showed a significant effect of depth on metabolic rate. This is discussed in terms of the adaptive and selective factors responsible for the well-known decline in metabolic rates of midwater crustaceans and fishes, an effect which does exceed the effect of temperature. It is suggested that the typical pattern for deeper living animals may be that metabolic rates on average vary as a function of depth due primarily to variation in temperature, except for the visually orienting pelagic groups (cephalopods, crustaceans and fishes). For those benthic forms which are particularly visually oriented and/or partially pelagic some significant depth-related decline in metabolism beyond that due to the decline in temperature is expected.

Effect of biochar application and soil temperature on characteristics of organic matter associated with aggregate-size and density fractions

NASA Astrophysics Data System (ADS)

Kaiser, Michael; Grunwald, Dennis; Marhan, Sven; Poll, Christian; Bamminger, Chris; Ludwig, Bernard

2016-04-01

Potential increases in soil temperature due to climate change might result in intensified soil organic matter (SOM) decomposition and thus higher CO2 emissions. Management options to increase and stabilize SOM include the application of biochar. However, the effects of biochar amendments under elevated soil temperatures on SOM dynamics are largely unknown. The objective of this study was to analyze the effect of biochar application and elevated soil temperature on the amount and composition of OM associated with fractions of different turnover kinetics. Samples were taken from four treatments of the Hohenheim Climate Change Experiment with the factors temperature (ambient or elevated by 2.5 °C in 4 cm depth, six years before sampling) and biochar (control and 30 t / ha Miscanthus pyrolysis biochar, one year before sampling) in two depths (0 - 5 and 5 - 15 cm). Basal respiration and microbial biomass C were analyzed within an incubation experiment. Aggregate size-fractions were separated by wet-sieving and the free light, occluded light (oLF), and heavy fractions were isolated by density fractionation. All fractions were analyzed for organic C and δ13C as well as by infrared spectroscopy. Preliminary data suggest that biochar significantly increased basal respiration and that the microbial biomass C was significantly affected by elevated temperature. No biochar-C was found in the microbial biomass. Biochar and elevated temperature had only minor effects on the organic C associated with aggregate-size classes, although biochar was incorporated into all fractions already after one year of application. Biochar application significantly increased the organic C associated with oLF. In most samples affected by biochar, the proportion of C=O groups was significantly increased. The results suggest that already after one year, biochar-mineral interactions were formed leading to an aggregate occlusion of applied biochar. At least in the short-term, the effect of biochar on the amount and composition of OM associated with different aggregate-size and density fractions seem to be independent from soil temperature.

Effect of water content and heating temperature on thermal properties of brown rice batter

NASA Astrophysics Data System (ADS)

Aboukzail, Jehan; Abdullah, Aminah; Ghani, Maaruf Abd

2015-09-01

The objectives of this research were to assess the effect of water content in the formulation (60%,80%, 100%, 105%, 110%, 120% flour basis) on starch gelatinization of brown rice batter, and to identify the effects of heat treatment at 50°C, 60°C, 70°C, 80°C on starch gelatinization and degree of starch gelatinization of brown rice batter and wheat dough. At 60% water content, there was no gelatinization of brown rice batter, but the batter was gelatinized by increasing the water content to 80%. No significant differences in onset (To) peak (Tp) and endest (Tend) temperature when the water content increased from 80% to 120%; however, enthalpy (ΔH) decreased when water content grew up. Heat treatment of brown rice batter at 60% water content made brown rice batter gelatinized. Starch gelatinization temperature To, Tend and ΔH did not have significant differences when temperature of heat treatment increased from 50°C to 80°C while Tp increased significantly (p<0.05) at 80°C. However, heat treatment had more effect on wheat dough compared to brown rice batter.

Intrapulpal Temperature Increases Caused by 445-nm Diode Laser-Assisted Debonding of Self-Ligating Ceramic Brackets During Simulated Pulpal Fluid Circulation.

PubMed

Stein, Steffen; Wenzler, Johannes; Hellak, Andreas; Schauseil, Michael; Korbmacher-Steiner, Heike; Braun, Andreas

2018-04-01

This study investigated temperature increases in dental pulp resulting from laser-assisted debonding of ceramic brackets using a 445-nm diode laser. Eighteen ceramic brackets were bonded in standardized manner to 18 caries-free human third molars. Pulpal fluid circulation was simulated by pumping distilled water at 37°C through the pulp chamber. The brackets were irradiated with a 445-nm diode laser. Temperatures were measured using a thermal camera at points P1 (center of the pulp) and P2 (in the hard dental tissue) at the baseline (T0), at the start and end of laser application (T1 and T2), and the maximum during the sequence (T max ). Significant differences in the temperatures measured at P1 and P2 were observed among T0, T1, T2, and T max . Significant increases in temperature were noted at points P1 and P2, between T1 and T2, T1 and T max , and T2 and T max . The maximum P2 values were significantly higher than at P1. The maximum temperature increase measured in the pulp was 2.23°C, lower than the critical threshold of 5.5°C. On the basis of the laser settings used, there is no risk to the vitality of dental pulp during laser-assisted debonding of ceramic brackets with a 445-nm diode laser.

[Effects of exogenous spermidine on lipid peroxidation and membrane proton pump activity of cucumber seedling leaves under high temperature stress].

PubMed

Tian, Jing; Guo, Shi-Rong; Sun, Jin; Wang, Li-Ping; Yang, Yan-Juan; Li, Bin

2011-12-01

Taking a relatively heat-resistant cucumber (Cucumis sativus) cultivar 'Jinchun No. 4' as test material, a sand culture experiment was conducted in growth chamber to investigate the effects of foliar spraying spermidine (Spd) on the lipid peroxidation, membrane proton pump activity, and corresponding gene expression of cucumber seedling leaves under high temperature stress. Compared with the control, foliar spraying Spd increased the plant height, stem diameter, dry and fresh mass, and leaf area significantly, and inhibited the increase of leaf relative conductivity, malondialdehyde (MDA) content, and lipoxygenase (LOX) activity effectively. Foliar spraying Spd also helped to the increase of leaf plasma membrane- and tonoplast H(+)-ATPase activity, but no significant difference was observed in the gene expression levels. These results suggested that exogenous Spd could significantly decrease the leaf lipid peroxidation and increase the proton pump activity, and thus, stabilize the leaf membrane structure and function, alleviate the damage induced by high temperature stress, and enhance the heat tolerance of cucumber seedlings.

The effect of temperature on the low cycle fatigue of type 316L stainless steel over the range 20-200°C

NASA Astrophysics Data System (ADS)

Chung, T. E.; Kalantary, M. R.; Faulkner, R. G.; Boutard, J.-L.

1992-09-01

Strain-controlled low cycle fatigue tests (with and without tensile hold) were performed on type 316L stainless steel over the temperature range 20-200°C. The results indicate that for strain ranges of less than 1%, the fatigue life was temperature independent. By contrast, for strain ranges of 1% or more, fatigue life decreased significantly as temperature was increased from 20 to approximately 50°C. It then increased with further increases in temperature until approximately 100°C and beyond when it became relatively temperature insensitive. Fatigue life at all temperatures was reduced with the superimposition of a speak tension hold of 50 s. A model based on the temperature-assisted diffusion of interstitial carbon atoms is proposed to explain the phenomenon.

Genetic aftereffects of increased temperature in Larix

Treesearch

Michael S. Greenwood; Keith W. Hutchinson

1996-01-01

We tested the hypothesis that temperature during gametogenesis and embryogenesis can affect progeny genotype and phenotype. Identical crosses were made among cloned parents of Larix spp. inside and outside a greenhouse, where the temperature inside averaged 4?C above the outside temperature. Significant growth differences as a function of crossing...

Response of sunshine bass (Morone chrysops x M. saxatilis) to digestible protein/dietary lipid density and ration size at summer culture temperatures in the Southern United States

USDA-ARS?s Scientific Manuscript database

Temperature and ammonia levels often increase dramatically in ponds during summer production of sunshine bass and summer temperatures are projected to increase in the Southern US. Extended periods of high ammonia result in fish stress, disease, mortality and significant loss of feeding days as pro...

Relative effects of climate change and wildfires on stream temperatures: A simulation modeling approach in a Rocky Mountain watershed

Treesearch

Lisa Holsinger; Robert E. Keane; Daniel J. Isaak; Lisa Eby; Michael K. Young

2014-01-01

Freshwater ecosystems are warming globally from the direct effects of climate change on air temperature and hydrology and the indirect effects on near-stream vegetation. In fire-prone landscapes, vegetative change may be especially rapid and cause significant local stream temperature increases but the importance of these increases relative to broader changes associated...

Coupling Meteorological, Land Surface and Water Temperature Models in the Mississippi River Basin

NASA Astrophysics Data System (ADS)

Tang, C.; Cooter, E. J.

2017-12-01

Water temperature is a significant factor influencing of the stream ecosystem and water management especially under climate change. In this study, we demonstrate a physically based semi-Lagrangian water temperature model (RBM) coupled with the Variable Infiltration Capacity (VIC) hydrology model and Weather Research & Forecasting Model (WRF) in the Mississippi River Basin (MRB). The results of this coupling compare favorably with observed water temperature data at river gages throughout the MRB. Further sensitivity analysis shows that mean water temperatures increase by 1.3°C, 1.5°C, and 1.8°C in northern, central and southern MRB zones, respectively, under a hypothetical uniform air temperature increase of 3°C. If air temperatures increase uniformly by 6°C in this scenario, then water temperatures are projected to increase by 3.3°C, 3.5°C and 4.0°C. Lastly, downscaled air temperatures from a global climate model are used to drive the coupled VIC and RBM model from 2020 to 2099. Average stream temperatures from 2020 to 2099 increase by 1°C to 8°C above 1950 to 2010 average water temperatures, with non-uniform increases along the river. In some portions of the MRB, stream temperatures could increase above survival thresholds for several native fish species, which are critical components of the stream ecosystem. The increased water temperature accelerates harmful algal blooming which results in a larger dead zone in the Gulf of Mexico.

Ion-ion dynamic structure factor, acoustic modes, and equation of state of two-temperature warm dense aluminum

NASA Astrophysics Data System (ADS)

Harbour, L.; Förster, G. D.; Dharma-wardana, M. W. C.; Lewis, Laurent J.

2018-04-01

The ion-ion dynamical structure factor and the equation of state of warm dense aluminum in a two-temperature quasiequilibrium state, with the electron temperature higher than the ion temperature, are investigated using molecular-dynamics simulations based on ion-ion pair potentials constructed from a neutral pseudoatom model. Such pair potentials based on density functional theory are parameter-free and depend directly on the electron temperature and indirectly on the ion temperature, enabling efficient computation of two-temperature properties. Comparison with ab initio simulations and with other average-atom calculations for equilibrium aluminum shows good agreement, justifying a study of quasiequilibrium situations. Analyzing the van Hove function, we find that ion-ion correlations vanish in a time significantly smaller than the electron-ion relaxation time so that dynamical properties have a physical meaning for the quasiequilibrium state. A significant increase in the speed of sound is predicted from the modification of the dispersion relation of the ion acoustic mode as the electron temperature is increased. The two-temperature equation of state including the free energy, internal energy, and pressure is also presented.

Influence of grain activation conditions on functional characteristics of brown rice flour.

PubMed

Singh, Arashdeep; Sharma, Savita; Singh, Baljit

2017-09-01

Grain activation is a natural processing technique that can be used to produce modified flours without chemical modification. Functional characteristics of brown rice flour as influenced by grain activation time and temperatures were investigated. Germination temperatures at 25 ℃, 30 ℃ and 35 ℃ and time for 12, 24, 36 and 48 h significantly influenced the functional properties of flour with modification of starch, protein and high enzymatic activity. Significant decrease in the bulk density, water absorption and swelling power of brown rice flour was observed in comparison to non-germinated flour. Gel consistency and oil absorption capacity of brown rice flour increased as the grain activation time and temperature were increased. Native flour had lowest emulsion and foaming properties, while increase in grain activation time and temperature enhanced the emulsifying and foaming properties of flour. Paste clarity of native flour was 54% which was reduced to 25.17%; however, increase in germination time and temperature increased the % synersis values of germinated flour. Native flour had least gelation concentration of 12% which increased to 25% after 48 h of germination at 35 ℃. Overall, germination can be used as a natural way to modify the functional properties of brown rice flours for their utilization in variety food products.

Antibiotic resistance increases with local temperature

NASA Astrophysics Data System (ADS)

MacFadden, Derek R.; McGough, Sarah F.; Fisman, David; Santillana, Mauricio; Brownstein, John S.

2018-06-01

Bacteria that cause infections in humans can develop or acquire resistance to antibiotics commonly used against them1,2. Antimicrobial resistance (in bacteria and other microbes) causes significant morbidity worldwide, and some estimates indicate the attributable mortality could reach up to 10 million by 20502-4. Antibiotic resistance in bacteria is believed to develop largely under the selective pressure of antibiotic use; however, other factors may contribute to population level increases in antibiotic resistance1,2. We explored the role of climate (temperature) and additional factors on the distribution of antibiotic resistance across the United States, and here we show that increasing local temperature as well as population density are associated with increasing antibiotic resistance (percent resistant) in common pathogens. We found that an increase in temperature of 10 °C across regions was associated with an increases in antibiotic resistance of 4.2%, 2.2%, and 2.7% for the common pathogens Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus. The associations between temperature and antibiotic resistance in this ecological study are consistent across most classes of antibiotics and pathogens and may be strengthening over time. These findings suggest that current forecasts of the burden of antibiotic resistance could be significant underestimates in the face of a growing population and climate change4.

Doping β-Ga2O3 with europium: influence of the implantation and annealing temperature

NASA Astrophysics Data System (ADS)

Peres, M.; Lorenz, K.; Alves, E.; Nogales, E.; Méndez, B.; Biquard, X.; Daudin, B.; Víllora, E. G.; Shimamura, K.

2017-08-01

β-Ga2O3 bulk single crystals were doped by ion implantation at temperatures from room temperature to 1000 °C, using a 300 keV Europium beam with a fluence of 1  ×  1015 at cm-2. Rising the implantation temperature from room temperature to 400-600 °C resulted in a significant increase of the substitutional Eu fraction and of the number of Eu ions in the 3+  charge state as well as in a considerable decrease of implantation damage. Eu is found in both charge states 2+  and 3+  and their relative fractions are critically dependent on the implantation and annealing temperature, suggesting that defects play an important role in stabilizing one of the charge states. The damage recovery during post-implant annealing is a complex process and typically defect levels first increase for intermediate annealing temperatures and a significant recovery of the crystal only starts around 1000 °C. Cathodoluminescence spectra are dominated by the sharp Eu3+ related intra-ionic 4f transition lines in the red spectral region. They show a strong increase of the emission intensity with increasing annealing temperature, in particular for samples implanted at elevated temperature, indicating the optical activation of Eu3+ ions. However, no direct correlation of emission intensity and Eu3+ fraction was found, again pointing to the important role of defects on the physical properties of these luminescent materials.

The influence of metabolic heat production on body temperature of a small lizard, Anolis carolinensis.

PubMed

Brown, Richard P; Au, Timothy

2009-06-01

Little is known about the impact of increased metabolism on body temperatures of small ectotherms. We found that postprandial metabolic rates of 5 g Anolis carolinensis lizards were elevated by factorial increases of 2.3+/-1.0 (mean+/-S.E.) at 26 degrees C and 3.8+/-2.1 at 30 degrees C over their fasting rates. Cloacal body temperatures exceeded environmental temperatures by a small amount in fasted individuals (26 degrees C: 0.3+/-0.02 degrees C, 30 degrees C: 0.3+/-0.02 degrees C), and by a significantly larger amount in fed individuals (26 degrees C: 1.0+/-0.06 degrees C, 30 degrees C: 0.8+/-0.08 degrees C). We conclude that an increased metabolic rate due to specific dynamic action leads to a small but significant elevation of body temperature in this species. Comparisons with thermal increments reported for a large (750 g) varanid lizard suggest that body size has only a minor influence on body-air temperature differentials of ectotherms. This is consistent with theoretical predictions. Finally, endogenous heat production could help elevate body temperatures in the wild and therefore play a minor role in thermoregulation.

Some rheological properties of sodium caseinate-starch gels.

PubMed

Bertolini, Andrea C; Creamer, Lawrence K; Eppink, Mieke; Boland, Mike

2005-03-23

The influence of sodium caseinate on the thermal and rheological properties of starch gels at different concentrations and from different botanical sources was evaluated. In sodium caseinate-starch gels, for all starches with the exception of potato starch, the sodium caseinate promoted an increase in the storage modulus and in the viscosity of the composite gel when compared with starch gels. The addition of sodium caseinate resulted in an increase in the onset temperature, the gelatinization temperature, and the end temperature, and there was a significant interaction between starch and sodium caseinate for the onset temperature, the peak temperature, and the end temperature. Microscopy results suggested that sodium caseinate promoted an increase in the homogeneity in the matrix of cereal starch gels.

Skeletonema marinoi (Bacillariophyceae) sensitivity to herbicides and effects of temperature increase on cellular responses to terbuthylazine exposure.

PubMed

Fiori, Emanuela; Pistocchi, Rossella

2014-02-01

The North East area of Italy is an intensively farmed area, where the use of herbicides has increased dramatically during the last years. Some of the most detected herbicides are triazine compounds, such as: simazine (SIM), terbuthylazine (TBA), its degradation product desethyl-terbuthylazine (D-TBA) and other herbicides, such as metolachlor (MET). In this paper, the sensitivity of the diatom Skeletonema marinoi to the most detected herbicides (TBA, D-TBA, SIM and MET) was preliminarily studied. All the pollutants tested significantly inhibited the diatom growth and photosynthetic efficiency (from the concentration of 15 μg L(-1)) with the exception of TBA which had the strongest effects on S. marinoi starting from the concentration of 5 μg L(-1). Consequently, cellular physiological responses to TBA exposure (1, 5, 10, 20 and 30 μg L(-1)) were further studied at increasing temperature conditions (15, 20 and 25°C). Inhibition of growth rate and photosynthetic efficiency was observed earlier and determined by lower TBA levels than those affecting cell growth. These responses were significantly enhanced at increasing temperature conditions when growth rates were higher than those measured at 15°C. Carbon cell content increased in the cultures exposed to high concentrations of TBA (from 20 μg L(-1)) compared to the controls, especially at high temperatures. Cell chlorophyll significantly increased from the added concentration of 10 μg L(-1) of TBA at all the temperatures and, as a consequence, also the Chl:C ratio significantly increased. The C:N ratio followed the pattern of nitrate uptake and was characterized, at all the temperatures, by low values during the lag phase in cultures with 20 and 30 μg L(-1) of TBA; in these conditions, in fact, the nutrient in the medium was exhausted later then in the controls. Only cultures exposed to 30 μg L(-1) of TBA at 25°C, which stopped to take up nutrients earlier and could not increase chlorophyll levels, did not display any growth capacity. This study shows that S. marinoi is affected by TBA concentrations lower than those affecting some harmful flagellate species frequently observed in the Adriatic Sea. Thus, it raises the question of the combined effects of herbicides pollution and high temperature pressures on phytoplankton composition. Copyright © 2013 Elsevier B.V. All rights reserved.

The Effect of Acclimation to Sublethal Temperature on Subsequent Susceptibility of Sitophilus zeamais Mostchulsky (Coleoptera: Curculionidae) to High Temperatures

PubMed Central

Lü, Jianhua; Zhang, Huina

2016-01-01

Heat treatment is a popular alternative to synthetic pesticides in disinfesting food-processing facilities and empty grain storages. Sitophilus zeamais Mostchulsky is one of the most cosmopolitan and destructive insects found in empty grain storage facilities and processing facilities. The effect of acclimation in S. zeamais adults to sublethal high temperature on their subsequent susceptibility to high temperatures was investigated. S. zeamais adults were acclimated to 36°C for 0 (as a control), 1, 3, and 5 h, and then were exposed at 43, 47, 51, and 55°C for different time intervals respectively. Acclimation to sublethal high temperature significantly reduced subsequent susceptibility of S. zeamais adults to lethal high temperatures of 43, 47, 51, and 55°C, although the mortality of S. zeamais adults significantly increased with increasing exposure time at lethal high temperatures. The mortality of S. zeamais adults with 1, 3, and 5 h of acclimation to 36°C was significantly lower than that of S. zeamais adults without acclimation when exposed to the same lethal high temperatures. The present results suggest that the whole facility should be heated to target lethal high temperature as soon as possible, avoiding decreasing the control effectiveness of heat treatment due to the acclimation in stored product insects to sublethal temperature. PMID:27462906

Effect of temperature on porosity of iron ore sinter with biochar derived from EFB

NASA Astrophysics Data System (ADS)

Purwanto, H.; Rozhan, A. N.; Zakiyuddin, A.; Mohamad, A. S.

2018-01-01

In this research, the replacement of fossil fuel energy (coke) with oil palm empty fruit bunch as a potential energy in sintering of iron ore was investigated. Carbon derived biomass has been produced by using oil palm empty fruit bunch by heat treatment process. In the present investigation, sintering process was carried out by heating the mixed iron ore and biochar at various temperatures. The apparent density and porosity for iron sinter show a significant increase and gradual decrement as the temperature increase, respectively. The porosity of iron sinter shows a gradual decrement from 950 °C to 1050 °C but up to 1150 °C it shows a significant decrement about 44%. Inferring to the micrograph, the agglomeration and assimilation of sinter at high temperature is better compared with low sintering temperature.

Effect of Strain Rate on Mechanical Properties of Wrought Sintered Tungsten at Temperatures above 2500 F

NASA Technical Reports Server (NTRS)

Sikora, Paul F.; Hall, Robert W.

1961-01-01

Specimens of wrought sintered commercially pure tungsten were made from 1/8-inch swaged rods. All the specimens were recrystallized at 4050 F for 1 hour prior to testing at temperatures from 2500 to 4000 F at various strain rates from 0.002 to 20 inches per inch per minute. Results showed that, at a constant temperature, increasing the strain rate increased the ultimate tensile strength significantly. The effects of both strain rate and temperature on the ultimate tensile strength of tungsten may be correlated by the linear parameter method of Manson and Haferd and may be used to predict the ultimate tensile strength at higher temperatures, 4500 and 5000 F. As previously reported, ductility, as measured by reduction of area in a tensile test, decreases with increasing temperature above about 3000 F. Increasing the strain rate at temperatures above 3000 F increases the ductility. Fractures are generally transgranular at the higher strain rates and intergranular at the lower strain rates.

Measurement of In Vitro Single Cell Temperature by Novel Thermocouple Nanoprobe in Acute Lung Injury Models.

PubMed

Wang, Xing; Chen, Qiuhua; Tian, Wenjuan; Wang, Jianqing; Cheng, Lu; Lu, Jun; Chen, Mingqi; Pei, Yinhao; Li, Can; Chen, Gong; Gu, Ning

2017-01-01

Energy metabolism may alter pattern differences in acute lung injury (ALI) as one of the causes but the detailed features at single-cellular level remain unclear. Changes in intercellular temperature and adenosine triphosphate (ATP) concentration within the single cell may help to understand the role of energy metabolism in causing ALI. ALI in vitro models were established by treating mice lung epithelial (MLE-12) cells with lipopolysaccharide (LPS), hydrogen peroxide (H2O2), hydrochloric acid (HCl) and cobalt chloride (CoCl2, respectively. 100 nm micro thermocouple probe (TMP) was inserted into the cytosol by micromanipulation system and thermoelectric readings were recorded to calculate the intracellular temperature based on standard curve. The total ATP contents for the MLE-12 cells were evaluated at different time intervals after treatments. A significant increase of intracellular temperature was observed after 10 or 20 μg/L LPS and HCl treatments. The HCl increased the temperature in a dose-dependent manner. On the contrary, H2O2 induced a significant decline of intracellular temperature after treatment. No significant difference in intracellular temperature was observed after CoCl2 exposure. The intracellular ATP levels decreased in a time-dependent manner after treatment with H2O2 and HCl, while the LPS and CoCl2 had no significant effect on ATP levels. The intracellular temperature responses varied in different ALI models. The concentration of ATP in the MLE-12 cells played part in the intracellular temperature changes. No direct correlation was observed between the intracellular temperature and concentration of ATP in the MLE-12 cells.

Rice grain yield and quality responses to free-air CO2 enrichment combined with soil and water warming.

PubMed

Usui, Yasuhiro; Sakai, Hidemitsu; Tokida, Takeshi; Nakamura, Hirofumi; Nakagawa, Hiroshi; Hasegawa, Toshihiro

2016-03-01

Rising air temperatures are projected to reduce rice yield and quality, whereas increasing atmospheric CO2 concentrations ([CO2 ]) can increase grain yield. For irrigated rice, ponded water is an important temperature environment, but few open-field evaluations are available on the combined effects of temperature and [CO2 ], which limits our ability to predict future rice production. We conducted free-air CO2 enrichment and soil and water warming experiments, for three growing seasons to determine the yield and quality response to elevated [CO2 ] (+200 μmol mol(-1) , E-[CO2 ]) and soil and water temperatures (+2 °C, E-T). E-[CO2 ] significantly increased biomass and grain yield by approximately 14% averaged over 3 years, mainly because of increased panicle and spikelet density. E-T significantly increased biomass but had no significant effect on the grain yield. E-T decreased days from transplanting to heading by approximately 1%, but days to the maximum tiller number (MTN) stage were reduced by approximately 8%, which limited the panicle density and therefore sink capacity. On the other hand, E-[CO2 ] increased days to the MTN stage by approximately 4%, leading to a greater number of tillers. Grain appearance quality was decreased by both treatments, but E-[CO2 ] showed a much larger effect than did E-T. The significant decrease in undamaged grains (UDG) by E-[CO2 ] was mainly the result of an increased percentage of white-base grains (WBSG), which were negatively correlated with grain protein content. A significant decrease in grain protein content by E-[CO2 ] accounted in part for the increased WBSG. The dependence of WBSG on grain protein content, however, was different among years; the slope and intercept of the relationship were positively correlated with a heat dose above 26 °C. Year-to-year variation in the response of grain appearance quality demonstrated that E-[CO2 ] and rising air temperatures synergistically reduce grain appearance quality of rice. © 2015 John Wiley & Sons Ltd.

Microstructures and Mechanical Properties of Inconel 718 Alloy at Ultralow Temperatures

NASA Astrophysics Data System (ADS)

Yao, C. G.; Lv, H. J.; Yi, D. Q.; Meng, S.; Xiao, L. R.; Wang, B.

2018-04-01

The microstructures and mechanical properties of powder metallurgy Inconel 718 alloy were investigated in the temperatures range between 25 and - 253 °C. Tensile strength increased with the decrease in temperature, while the ductility first increased and then decreased. There was no significant change in impact toughness. When the temperature was - 253 °C, a zigzag stress-strain curve was observed for the alloy, owing to the interaction of dislocation glide and twinning, which effectively maintained the relatively good ductility.

Microstructures and Mechanical Properties of Inconel 718 Alloy at Ultralow Temperatures

NASA Astrophysics Data System (ADS)

Yao, C. G.; Lv, H. J.; Yi, D. Q.; Meng, S.; Xiao, L. R.; Wang, B.

2018-05-01

The microstructures and mechanical properties of powder metallurgy Inconel 718 alloy were investigated in the temperatures range between 25 and - 253 °C. Tensile strength increased with the decrease in temperature, while the ductility first increased and then decreased. There was no significant change in impact toughness. When the temperature was - 253 °C, a zigzag stress-strain curve was observed for the alloy, owing to the interaction of dislocation glide and twinning, which effectively maintained the relatively good ductility.

Climatic indicators over Catalonia during the last century

NASA Astrophysics Data System (ADS)

Busto, M.; Prohom, M.

2010-09-01

The Meteorological Service of Catalonia releases a yearly bulletin whose main objective is to try to detect climate trends over Catalonia during the last decades. Climate indicators are obtained from the analysis of historical daily air temperature, sea temperature and rainfall series. Those series have been first completed, analyzed for quality control and homogenized to ensure its final reliability. Regarding homogenization, monthly air temperature series have been tested and corrected according to the methodology proposed by Caussinus and Mestre (2004). For the two longest air temperature series, the calculated correction factors have been transferred to the daily values following Vincent et al. (2002) recommendations, while no significant inhomogeneities have been detected for precipitation series. The analysis of temperature trends, for the period 1950-2010, of 17 selected climatic series spread across the territory shows a common temperature increase between +0.19 to +0.24 °C/decade. This warming trend is uniform and no specific sub-regional trends are detected. Furthermore, the seasonal approach reveals that mean maximum temperature increases at a higher rate than mean minimum temperature. The summer temperature rise is the most significant, between +0.32 and +0.44 °C/decade, while autumn is the only season showing no significant positive trend. The summer maximum temperature shows the highest increase, exceeding +0.39 °C/decade in all the 17 series. The climatic extremes analysis of the longest Catalan series (Ebre Observatory in Roquetes, Tarragona, since 1905 and Fabra Observatory in Barcelona since 1913) reveals an increase in the number of summer days, tropical nights, minimum of maximum temperature, warm days and warm nights, and a decrease in the number of frost days, cold nights, cold days and cold spell duration indicator. Concerning precipitation, the only significant trend is the reduction of snow days. These trends were calculated according to the Expert Team on Climate Change Detection and Indices (ETCCDI). The sea temperature trend in l'Estartit (NE coast of Catalonia, Costa Brava) since 1974 shows a steady increment in all the measured levels (surface, -20 m, -50 m and -80 m) of +0,33 °C/decade on average. Temperature increment is maximum at -20 m, with +0.36 °C/decade variation. Moreover, there is an increase in the sea level of +3.35 cm/decade. CAUSSINUS, H. and MESTRE, O. (2004): Detection and correction of artificial shifts in climate series. Journal of the Royal Statistical Society Series C - Applied Statistics, 53, 405-425. VINCENT, L.A., ZHANG, X., BONSAL, B.R., HOGG, W.D. (2002): Homogenization of daily temperatures over Canada. Journal of Climate, 15, 1322-1334

Hydrology and trout populations of cold-water rivers of Michigan and Wisconsin

USGS Publications Warehouse

Hendrickson, G.E.; Knutilla, R.L.

1974-01-01

Statistical multiple-regression analyses showed significant relationships between trout populations and hydrologic parameters. Parameters showing the higher levels of significance were temperature, hardness of water, percentage of gravel bottom, percentage of bottom vegetation, variability of streamflow, and discharge per unit drainage area. Trout populations increase with lower levels of annual maximum water temperatures, with increase in water hardness, and with increase in percentage of gravel and bottom vegetation. Trout populations also increase with decrease in variability of streamflow, and with increase in discharge per unit drainage area. Most hydrologic parameters were significant when evaluated collectively, but no parameter, by itself, showed a high degree of correlation with trout populations in regression analyses that included all the streams sampled. Regression analyses of stream segments that were restricted to certain limits of hardness, temperature, or percentage of gravel bottom showed improvements in correlation. Analyses of trout populations, in pounds per acre and pounds per mile and hydrologic parameters resulted in regression equations from which trout populations could be estimated with standard errors of 89 and 84 per cent, respectively.

The lagged effect of cold temperature and wind chill on cardiorespiratory mortality in Scotland

PubMed Central

Carder, M; McNamee, R; Beverland, I; Elton, R; Cohen, G; Boyd, J; Agius, R

2005-01-01

Aims: To investigate the lagged effects of cold temperature on cardiorespiratory mortality and to determine whether "wind chill" is a better predictor of these effects than "dry bulb" temperature. Methods: Generalised linear Poisson regression models were used to investigate the relation between mortality and "dry bulb" and "wind chill" temperatures in the three largest Scottish cities (Glasgow, Edinburgh, and Aberdeen) between January 1981 and December 2001. Effects of temperature on mortality (lags up to one month) were quantified. Analyses were conducted for the whole year and by season (cool and warm seasons). Main results: Temperature was a significant predictor of mortality with the strongest association observed between temperature and respiratory mortality. There was a non-linear association between mortality and temperature. Mortality increased as temperatures fell throughout the range, but the rate of increase was steeper at temperatures below 11°C. The association between temperature and mortality persisted at lag periods beyond two weeks but the effect size generally decreased with increasing lag. For temperatures below 11°C, a 1°C drop in the daytime mean temperature on any one day was associated with an increase in mortality of 2.9% (95% CI 2.5 to 3.4), 3.4% (95% CI 2.6 to 4.1), 4.8% (95% CI 3.5 to 6.2) and 1.7% (95% CI 1.0 to 2.4) over the following month for all cause, cardiovascular, respiratory, and "other" cause mortality respectively. The effect of temperature on mortality was not observed to be significantly modified by season. There was little indication that "wind chill" temperature was a better predictor of mortality than "dry bulb" temperature. Conclusions: Exposure to cold temperature is an important public health problem in Scotland, particularly for those dying from respiratory disease. PMID:16169916

Effects of temperature on sustained swimming performance and swimming kinematics of the chub mackerel Scomber japonicus.

PubMed

Dickson, Kathryn A; Donley, Jeanine M; Sepulveda, Chugey; Bhoopat, Lisa

2002-04-01

The effects of a 6 degrees C difference in water temperature on maximum sustained swimming speed, swimming energetics and swimming kinematics were measured in the chub mackerel Scomber japonicus (Teleostei: Scombridae), a primarily coastal, pelagic predator that inhabits subtropical and temperate transition waters of the Atlantic, Pacific and Indian Oceans. New data for chub mackerel acclimated to 18 degrees C are compared with published data from our laboratory at 24 degrees C. Twelve individuals acclimated to each of two temperatures (15.6-26.3 cm fork length, FL, and 34-179 g at 18 degrees C; 14.0-24.7 cm FL and 26-156 g at 24 degrees C) swam at a range of speeds in a temperature-controlled Brett-type respirometer, at the respective acclimation temperature. At a given fish size, the maximum speed that S. japonicus was able to maintain for a 30-min period, while swimming steadily using slow, oxidative locomotor muscle (U(max,c)), was significantly greater at 24 than at 18 degrees C (52.5-97.5 cm s(-1) at 18 degrees C and 70-120 cm s(-1) at 24 degrees C). At a given speed and fish size, the rate of oxygen consumption (VO(2)) was significantly higher at 24 than at 18 degrees C because of a higher net cost of transport (1073-4617 J km(-1) kg(-1) at 18 degrees C and 2708-14895 J km(-1) kg(-1) at 24 degrees C). Standard metabolic rate, calculated by extrapolating the logO(2) versus swimming speed relationship to zero speed, did not vary significantly with temperature or fish mass (126.4+/-67.2 mg O(2) h(-1) kg(-1) at 18 degrees C and 143.2+/-80.3 mg O(2) h(-1) kg(-1) at 24 degrees C; means +/- S.D., N=12). Swimming kinematics was quantified from high-speed (120 Hz) video recordings analyzed with a computerized, two-dimensional motion-analysis system. At a given speed and fish size, there were no significant effects of temperature on tail-beat frequency, tail-beat amplitude or stride length, but propulsive wavelength increased significantly with temperature as a result of an increase in propulsive wave velocity. Thus, the main effects of temperature on chub mackerel swimming were increases in both U(max,c) and the net cost of swimming at 24 degrees C. Like other fishes, S. japonicus apparently must recruit more slow, oxidative muscle fibers to swim at a given sustainable speed at the lower temperature because of the reduced power output. Thus, the 24 degrees C mackerel reach a higher speed before they must recruit the fast, glycolytic fibers, thereby increasing U(max,c) at 24 degrees C. By quantifying in vivo the effects of temperature on the swimming performance of an ectothermic species that is closely related to the endothermic tunas, this study also provides evidence that maintaining the temperature of the slow, oxidative locomotor muscle at 6 degrees C or more above ambient water temperature in tunas should significantly increase sustainable swimming speeds, but also increase the energetic cost of swimming, unless cardiac output limits muscle performance.

Resistant Starch Contents of Native and Heat-Moisture Treated Jackfruit Seed Starch

PubMed Central

Kittipongpatana, Ornanong S.

2015-01-01

Native jackfruit seed starch (JFS) contains 30% w/w type II resistant starch (RS2) and can potentially be developed as a new commercial source of RS for food and pharmaceutical application. Heat-moisture treatment (HMT) was explored as a mean to increase RS content of native JFS. The effect of the conditions was tested at varied moisture contents (MC), temperatures, and times. Moisture levels of 20–25%, together with temperatures 80–110°C, generally resulted in increases of RS amount. The highest amount of RS (52.2%) was achieved under treatment conditions of 25% MC and 80°C, for 16 h (JF-25-80-16). FT-IR peak ratio at 1047/1022 cm−1 suggested increases in ordered structure in several HMT-JFS samples with increased RS. SEM showed no significant change in the granule appearance, except at high moisture/temperature treatment. XRD revealed no significant change in peaks intensities, suggesting the crystallinity within the granule was mostly retained. DSC showed increases in T g and, in most cases, ΔT, as the MC was increased in the samples. Slight but significant decreases in ΔH were observed in samples with low RS, indicating that a combination of high moisture and temperature might cause partial gelatinization. HMT-JFS with higher RS exhibited less swelling, while the solubility remained mostly unchanged. PMID:25642454

Assessment of circadian rhythms of both skin temperature and motor activity in infants during the first 6 months of life.

PubMed

Zornoza-Moreno, Matilde; Fuentes-Hernández, Silvia; Sánchez-Solis, Manuel; Rol, María Ángeles; Larqué, Elvira; Madrid, Juan Antonio

2011-05-01

The authors developed a method useful for home measurement of temperature, activity, and sleep rhythms in infants under normal-living conditions during their first 6 mos of life. In addition, parametric and nonparametric tests for assessing circadian system maturation in these infants were compared. Anthropometric parameters plus ankle skin temperature and activity were evaluated in 10 infants by means of two data loggers, Termochron iButton (DS1291H, Maxim Integrated Products, Sunnyvale, CA) for temperature and HOBO Pendant G (Hobo Pendant G Acceleration, UA-004-64, Onset Computer Corporation, Bourne, MA) for motor activity, located in special baby socks specifically designed for the study. Skin temperature and motor activity were recorded over 3 consecutive days at 15 days, 1, 3, and 6 mos of age. Circadian rhythms of skin temperature and motor activity appeared at 3 mos in most babies. Mean skin temperature decreased significantly by 3 mos of life relative to previous measurements (p = .0001), whereas mean activity continued to increase during the first 6 mos. For most of the parameters analyzed, statistically significant changes occurred at 3-6 mos relative to 0.5-1 mo of age. Major differences were found using nonparametric tests. Intradaily variability in motor activity decreased significantly at 6 mos of age relative to previous measurements, and followed a similar trend for temperature; interdaily stability increased significantly at 6 mos of age relative to previous measurements for both variables; relative amplitude increased significantly at 6 mos for temperature and at 3 mos for activity, both with respect to previous measurements. A high degree of correlation was found between chronobiological parametric and nonparametric tests for mean and mesor and also for relative amplitude versus the cosinor-derived amplitude. However, the correlation between parametric and nonparametric equivalent indices (acrophase and midpoint of M5, interdaily stability and Rayleigh test, or intradaily variability and P(1)/P(ultradian)) despite being significant, was lower for both temperature and activity. The circadian function index (CFI index), based on the integrated variable temperature-activity, increased gradually with age and was statistically significant at 6 mos of age. At 6 mos, 90% of the infants' rest period coincided with the standard sleep period of their parents, defined from 23:00 to 07:00 h (dichotomic index I < O; when I < O = 100%, there is a complete coincidence between infant nocturnal rest period and the standard rest period), whereas at 15 days of life the coincidence was only 75%. The combination of thermometry and actimetry using data loggers placed in infants' socks is a reliable method for assessing both variables and also sleep rhythms in infants under ambulatory conditions, with minimal disturbance. Using this methodological approach, circadian rhythms of skin temperature and motor activity appeared by 3 mos in most babies. Nonparametric tests provided more reliable information than cosinor analysis for circadian rhythm assessment in infants.

Heatwaves and Heat-Related Mortality in India

NASA Astrophysics Data System (ADS)

Mazdiyasni, O.; AghaKouchak, A.; Davis, S. J.; Madadgar, S.; Sengupta, A.; Ragno, E.

2016-12-01

Global temperatures are rising, causing increases in the frequency and severity of extreme climatic events, such as droughts and heatwaves. Here we present an analysis of the changes in temperature, number of heatwaves, and heat-related morality rates in India from 1960 - 2009, using data from the India Meteorological Department. We show that the changes in heatwaves from 1960 - 2009 are statistically significant. We then use a copula-based conditional probabilistic model to determine change in mortality in response to change in mean summer temperatures. We show that only 0.5 °C increase in mean summer temperatures in India causes a 140% increase in the probability of heat-related mortality. As global temperatures rise, heat-related mortality rates will increase in developing countries similar to India due to increasing heatwaves and high vulnerability to increased summer temperatures. International aid organizations should implement policies for improved infrastructure and disaster response plans across the developing world to assist in curbing the climate change effects on human health.

Relationship of blood corticosterone, immunoglobulin and haematological values in young crocodiles (Crocodylus porosus) to water temperature, clutch of origin and body weight.

PubMed

Turton, J A; Ladds, P W; Manolis, S C; Webb, G J

1997-02-01

To examine whether sub-optimal temperature induced stress and immunosuppression in farmed saltwater crocodile (Crocodylus porosus) hatchlings. A clinico-pathological study. A total of 140 hatchlings were used. Body weight and length, plasma corticosterone and immunoglobulin concentrations and total and differential white blood cell counts were measured in 140 hatchlings from five clutches divided between five water temperature treatment groups. Initially all groups were housed at 32 degrees C for 10 weeks, then two groups (L, LC) were changed to low temperature (28 degrees C) and two groups (H, HC) to high temperature (36 degrees C), while one group (C) remained at 32 degrees C. The LC and HC groups were maintained at these temperatures for 10 days, after which the water temperature of both groups was returned to 32 degrees C. Blood samples were collected twice (at 6 and 9 weeks of age) before the initial temperature change, and at 10 days and 4 weeks after the initial temperature change (at 11.5 and 14 weeks of age). Except for an increase in plasma corticosterone in the HC group and a decrease in the L group when the temperature change was first introduced, changes in plasma corticosterone were not significant. There were no significant changes in immunoglobulin concentrations. There were, however, significant decreases in the total white cell and lymphocyte counts in the LC group after the temperature was decreased to 28 degrees C, and an increase in these counts after water temperature was returned to 32 degrees C. Clutch of origin had significant effects on body weight and length gains, and there were negative relationships between body weight and corticosterone concentrations and between body weight and immunoglobulin concentrations. As haematological changes indicative of stress were not associated with significant changes in serum corticosterone, immunosuppression in young crocodiles may be independent of the hypothalamic-pituitary-adrenal cortical axis.

Effect of incubation temperature and time on the precision of data generated by antibiotic disc diffusion assays.

PubMed

Smith, P; Kronvall, G

2015-07-01

The influence on the precision of disc diffusion data of the conditions under which the tests were performed was examined by analysing multilaboratory data sets generated after incubation at 35 °C for 18 h, at 28 °C for 24 h and 22 °C for 24 h and 48 h. Analyses of these data sets demonstrated that precision was significantly and progressively decreased as the test temperature was reduced from 35 to 22 °C. Analysis of the data obtained at 22 °C also showed the precision was inversely related to the time of incubation. Temperature and time related decreases in precision were not related to differences in the mean zone sizes of the data sets obtained under these test conditions. Analysis of the zone data obtained at 28 and 22 °C as single laboratory sets demonstrated that reductions of incubation temperature resulted in significant increases in both intralaboratory and interlaboratory variation. Increases in incubation time at 22 °C were, however, associated with statistically significant increases in interlaboratory variation but not with any significant increase in intralaboratory variation. The significance of these observations for the establishment of the acceptable limits of precision of data sets that can be used for the setting of valid epidemiological cut-off values is discussed. © 2014 John Wiley & Sons Ltd.

The effects of heated and room-temperature abdominal lavage solutions on core body temperature in dogs undergoing celiotomy.

PubMed

Nawrocki, Michael A; McLaughlin, Ron; Hendrix, P K

2005-01-01

To document the magnitude of temperature elevation obtained with heated lavage solutions during abdominal lavage, 18 dogs were lavaged with sterile isotonic saline intraoperatively (i.e., during a celiotomy). In nine dogs, room-temperature saline was used. In the remaining nine dogs, saline heated to 43+/-2 degrees C (110+/-4 degrees F) was used. Esophageal, rectal, and tympanic temperatures were recorded every 60 seconds for 15 minutes after initiation of the lavage. Temperature levels decreased in dogs lavaged with room-temperature saline. Temperature levels increased significantly in dogs lavaged with heated saline after 2 to 6 minutes of lavage, and temperatures continued to increase throughout the 15-minute lavage period.

Gender differences in the effects of cathinone and the interaction with caffeine on temperature and locomotor activity in the rat.

PubMed

Alsufyani, Hadeel A; Docherty, James R

2017-08-15

We have investigated gender differences in the effects of cathinone and the interaction with caffeine on temperature and movement activity in Wistar rats. Telemetry probes were implanted in rats under isoflurane anaesthesia, and 7 days later, temperature and activity were recorded in conscious unrestrained animals. Caffeine (10mg/lkg) or vehicle, and 30min later, cathinone (5mg/kg) or vehicle, were injected subcutaneously. Cathinone produced significant and marked increases in activity, and the response to cathinone was significantly greater in female animals. The combination of caffeine and cathinone causes a short lived potentiation followed by a prolonged inhibition of the activity response to cathinone. Cathinone alone had minor effects on temperature. However, the combination of caffeine and cathinone produced a significant acute rise in temperature only in male rats in the 90min after cathinone injection. Hence, cathinone caused greater increases in activity in female than in male rats. Secondly, caffeine produced an initial potentiation followed by a prolonged inhibition of the activity response to cathinone. Thirdly, cathinone in combination with caffeine significantly raised temperature acutely in male but not female rats. These differences highlight the need to carry out gender studies of the actions of stimulants. Copyright © 2017 Elsevier B.V. All rights reserved.

Combined effects of constant sublethal UVA irradiation and elevated temperature on the survival and general metabolism of the convict-cichlid fish, Cichlasoma nigrofasciatum.

PubMed

Winckler, K; Fidhiany, L

1996-04-01

In a previous study we observed that a constant sublethal UVA (320-400 nm) irradiation had a significant effect on the general metabolism in the Convict-cichlid fish (Cichlasoma nigrofasciatum) [Winckler, K. and Fidhiany, L. (1996) J. Photochem. Photobiol. B. Biol. (In press)]. In the present study we show that sublethal UVA irradiation in combination with elevated environmental temperature has a deleterious effect on the same population. The threshold temperature for a sudden increase in mortality of fish receiving an additional sublethal UVA irradiation was 32 degrees C. Prior to the increased mortality, the fish started to avoid the UV light source when the water temperature increased to 31.5 degrees C. Mortality decreased when the temperature declined below 31.5 degrees C. As soon as the temperature changed to normal (adapted) condition (27-29 degrees C) mortality returned to normal levels. In contrast, no changes of fish behavior or mortality were observed at elevated temperature in the nonirradiated reference population. The percentages of fish surviving the high temperature stress were 21.9% for the UVA population and 96.8% for the reference population. The specific oxygen consumption (SOC, average +/- SD) of the survivors from the UVA population during temperature stress was 0.21 +/- 0.05 mg O2 h-1 g body weight (BW)-1, while it was 0.54 +/- 0.11 mg O2 h-1 g BW-1 in the reference population. After the environmental temperature returned below the apparent upper temperature tolerance limit, the oxygen consumption of the UVA population gradually normalized. The SOC measured at different temperature levels--after after the fish passed the temperature stress--showed no significant differences between the UVA population and its reference at 23, 25, 27 and 29 degrees C. However, the SOC at 31 degrees C was significantly (P < 0.05) lower than reference, while at 33 degrees C it was higher (P < 0.10).

Effects of temperature on feed intake and plasma chemistry after exhaustive exercise in triploid brown trout (Salmo trutta L).

PubMed

Preston, Andrew C; Taylor, John F; Fjelldal, Per Gunnar; Hansen, Tom; Migaud, Hervé

2017-04-01

The physiological effect of temperature on feed intake and haematological parameters after exhaustive swimming in diploid and triploid brown trout (Salmo trutta) was investigated. Trout were exposed to an incremental temperature challenge (2 °C/day) from ambient (6 °C) to either 10 or 19 °C. Feed intake profiles did not differ between ploidy at 10 °C; however, triploids had a significantly higher total feed intake at 19 °C. After 24 days, each temperature-ploidy group was exposed to exhaustive swimming for 10 min. The haematological response differed between ploidy, with the magnitude of the response affected by temperature and ploidy. Post-exercise, acid-base and ionic differences were observed. Plasma lactate increased significantly from rest for both temperature and ploidy groups, but glucose increased significantly at higher temperature. Post-exercise, triploids at 19 °C had significantly higher osmolality and cholesterol than diploids, but differences were resumed within 4 h. Elevated alkaline phosphatase (ALP) and aspartate aminotransferase (AST) in fish at higher temperature suggested greater tissue damage; however, both ploidy responded similarly. Despite no significant differences in deformity prevalence, the type and location of deformities observed differed between ploidy (decreased intervertebral space with higher prevalence in tail area and fin regions for diploids, while vertebral compression, fusion in cranial and caudal trunks for triploids). These results suggest triploids have greater appetite than diploids at elevated temperature and that triploids suffer similar blood disturbances after exercise as diploids. These findings have implications for the management of freshwater ecosystems and suggest that stocking triploid brown trout may offer an alternative to diploid brown trout.

Human-modified temperatures induce species changes: Joint attribution.

PubMed

Root, Terry L; MacMynowski, Dena P; Mastrandrea, Michael D; Schneider, Stephen H

2005-05-24

Average global surface-air temperature is increasing. Contention exists over relative contributions by natural and anthropogenic forcings. Ecological studies attribute plant and animal changes to observed warming. Until now, temperature-species connections have not been statistically attributed directly to anthropogenic climatic change. Using modeled climatic variables and observed species data, which are independent of thermometer records and paleoclimatic proxies, we demonstrate statistically significant "joint attribution," a two-step linkage: human activities contribute significantly to temperature changes and human-changed temperatures are associated with discernible changes in plant and animal traits. Additionally, our analyses provide independent testing of grid-box-scale temperature projections from a general circulation model (HadCM3).

Impact of the 3 °C temperature rise on bacterial growth and carbon transfer towards higher trophic levels: Empirical models for the Adriatic Sea

NASA Astrophysics Data System (ADS)

Šolić, Mladen; Krstulović, Nada; Šantić, Danijela; Šestanović, Stefanija; Kušpilić, Grozdan; Bojanić, Natalia; Ordulj, Marin; Jozić, Slaven; Vrdoljak, Ana

2017-09-01

The Mediterranean Sea (including the Adriatic Sea) has been identified as a 'hotspot' for climate change, with the prediction of the increase in water temperature of 2-4 °C over the next few decades. Being mainly oligotrophic, and strongly phosphorus limited, the Adriatic Sea is characterized by the important role of the microbial food web in production and transfer of biomass and energy towards higher trophic levels. We hypothesized that predicted 3 °C temperature rise in the near future might cause an increase of bacterial production and bacterial losses to grazers, which could significantly enlarge the trophic base for metazoans. This empirical study is based on a combined 'space-for-time substitution' analysis (which is performed on 3583 data sets) and on an experimental approach (36 in situ grazing experiments performed at different temperatures). It showed that the predicted 3 °C temperature increase (which is a result of global warming) in the near future could cause a significant increase in bacterial growth at temperatures lower than 16 °C (during the colder winter-spring period, as well as in the deeper layers). The effect of temperature on bacterial growth could be additionally doubled in conditions without phosphorus limitation. Furthermore, a 3 °C increase in temperature could double the grazing on bacteria by heterotrophic nanoflagellate (HNF) and ciliate predators and it could increase the proportion of bacterial production transferred to the metazoan food web by 42%. Therefore, it is expected that global warming may further strengthen the role of the microbial food web in a carbon cycle in the Adriatic Sea.

Amphetamine enhances endurance by increasing heat dissipation.

PubMed

Morozova, Ekaterina; Yoo, Yeonjoo; Behrouzvaziri, Abolhassan; Zaretskaia, Maria; Rusyniak, Daniel; Zaretsky, Dmitry; Molkov, Yaroslav

2016-09-01

Athletes use amphetamines to improve their performance through largely unknown mechanisms. Considering that body temperature is one of the major determinants of exhaustion during exercise, we investigated the influence of amphetamine on the thermoregulation. To explore this, we measured core body temperature and oxygen consumption of control and amphetamine-trea ted rats running on a treadmill with an incrementally increasing load (both speed and incline). Experimental results showed that rats treated with amphetamine (2 mg/kg) were able to run significantly longer than control rats. Due to a progressively increasing workload, which was matched by oxygen consumption, the control group exhibited a steady increase in the body temperature. The administration of amphetamine slowed down the temperature rise (thus decreasing core body temperature) in the beginning of the run without affecting oxygen consumption. In contrast, a lower dose of amphetamine (1 mg/kg) had no effect on measured parameters. Using a mathematical model describing temperature dynamics in two compartments (the core and the muscles), we were able to infer what physiological parameters were affected by amphetamine. Modeling revealed that amphetamine administration increases heat dissipation in the core. Furthermore, the model predicted that the muscle temperature at the end of the run in the amphetamine-treated group was significantly higher than in the control group. Therefore, we conclude that amphetamine may mask or delay fatigue by slowing down exercise-induced core body temperature growth by increasing heat dissipation. However, this affects the integrity of thermoregulatory system and may result in potentially dangerous overheating of the muscles. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Time-Temperature Profiling of United Kingdom Consumers' Domestic Refrigerators.

PubMed

Evans, Ellen W; Redmond, Elizabeth C

2016-12-01

Increased consumer demand for convenience and ready-to-eat food, along with changes to consumer food purchase and storage practices, have resulted in an increased reliance on refrigeration to maximize food safety. Previous research suggests that many domestic refrigerators operate at temperatures exceeding recommendations; however, the results of several studies were determined by means of one temperature data point, which, given temperature fluctuation, may not be a true indicator of actual continual operating temperatures. Data detailing actual operating temperatures and the effects of consumer practices on temperatures are limited. This study has collated the time-temperature profiles of domestic refrigerators in consumer kitchens (n = 43) over 6.5 days with concurrent self-reported refrigerator usage. Overall, the findings established a significant difference (P < 0.05) between one-off temperature (the recording of one temperature data point) and mean operating temperature. No refrigerator operated at ≤5.0°C for the entire duration of the study. Mean temperatures exceeding 5.0°C were recorded in the majority (91%) of refrigerators. No significant associations or differences were determined for temperature profiles and demographics, including household size, or refrigerator characteristics (age, type, loading, and location). A positive correlation (P < 0.05) between room temperature and refrigerator temperature was determined. Reported door opening frequency correlated with temperature fluctuation (P < 0.05). Thermometer usage was determined to be infrequent. Cumulatively, research findings have established that the majority of domestic refrigerators in consumer homes operate at potentially unsafe temperatures and that this is influenced by consumer usage. The findings from this study may be utilized to inform the development of shelf-life testing based on realistic domestic storage conditions. Furthermore, the data can inform the development of future educational interventions to increase safe domestic refrigeration practices.

Effects of elevated CO2 and temperature on phytoplankton community biomass, species composition and photosynthesis during an experimentally induced autumn bloom in the western English Channel

NASA Astrophysics Data System (ADS)

Keys, Matthew; Tilstone, Gavin; Findlay, Helen S.; Widdicombe, Claire E.; Lawson, Tracy

2018-05-01

The combined effects of elevated pCO2 and temperature were investigated during an experimentally induced autumn phytoplankton bloom in vitro sampled from the western English Channel (WEC). A full factorial 36-day microcosm experiment was conducted under year 2100 predicted temperature (+4.5 °C) and pCO2 levels (800 µatm). Over the experimental period total phytoplankton biomass was significantly influenced by elevated pCO2. At the end of the experiment, biomass increased 6.5-fold under elevated pCO2 and 4.6-fold under elevated temperature relative to the ambient control. By contrast, the combined influence of elevated pCO2 and temperature had little effect on biomass relative to the control. Throughout the experiment in all treatments and in the control, the phytoplankton community structure shifted from dinoflagellates to nanophytoplankton . At the end of the experiment, under elevated pCO2 nanophytoplankton contributed 90 % of community biomass and was dominated by Phaeocystis spp. Under elevated temperature, nanophytoplankton comprised 85 % of the community biomass and was dominated by smaller nanoflagellates. In the control, larger nanoflagellates dominated whilst the smallest nanophytoplankton contribution was observed under combined elevated pCO2 and temperature ( ˜ 40 %). Under elevated pCO2, temperature and in the control there was a significant decrease in dinoflagellate biomass. Under the combined effects of elevated pCO2 and temperature, dinoflagellate biomass increased and was dominated by the harmful algal bloom (HAB) species, Prorocentrum cordatum. At the end of the experiment, chlorophyll a (Chl a) normalised maximum photosynthetic rates (PBm) increased > 6-fold under elevated pCO2 and > 3-fold under elevated temperature while no effect on PBm was observed when pCO2 and temperature were elevated simultaneously. The results suggest that future increases in temperature and pCO2 simultaneously do not appear to influence coastal phytoplankton productivity but significantly influence community composition during autumn in the WEC.

Seasonal variation in the acute presentation of urinary calculi over 8 years in Auckland, New Zealand.

PubMed

Lo, Sum Sum; Johnston, Richard; Al Sameraaii, Ahmed; Metcalf, Patricia A; Rice, Michael L; Masters, Jonathan G

2010-07-01

Symptom prevalence (retrospective cohort) Level of Evidence 2b. To determine the incidence of acute presentation of urinary calculi (UC) in Auckland, New Zealand, during the period 1999-2007, and whether there was any significant seasonal variation. The details of all UC within the population presenting acutely to public hospitals in Auckland between 1999 and 2007 were collected using clinical coding searches International Classification of Disease 10th revision (Australian Modification) N132 and N20. Climatic variables for the Auckland region were obtained from the National Institute of Water and Atmospheric Research, New Zealand. The mean atmospheric temperature, hours of sunshine and humidity data were calculated monthly for this period. During the study there were 7668 acute presentations of UC in the Auckland region. A Poisson regression model showed that the number of presentations was significantly related to temperature (P < 0.001) and hours of sunshine (P = 0.004) but not humidity (P = 0.14). For each degree increase in temperature the number of presentations increased by 2.8% (95% confidence interval 1.3-4.3%). For each 1-h increase in sunshine, the number of presentations increased by 0.2% (0.06-0.33)%. The acute presentation of UC in Auckland, New Zealand, varies significantly with temperature and hours of sunshine. Humidity was not a significant factor.

[Temperature sensitivity of soil organic carbon mineralization and β-glucosidase enzymekinetics in the northern temperate forests at different altitudes, China].

PubMed

Fan, Jin-juan; Li, Dan-dan; Zhang, Xin-yu; He, Nian-peng; Bu, Jin-feng; Wang, Qing; Sun, Xiao-min; Wen, Xue-fa

2016-01-01

Soil samples, which were collected from three typical forests, i.e., Betula ermanii forest, coniferous mixed broad-leaved forest, and Pinus koraiensis forest, at different altitudes along the southern slope of Laotuding Mountain of Changbai Mountain range in Liaoning Province of China, were incubated over a temperature gradient in laboratory. Soil organic carbon mineralization rates (Cmin), soil β-1,4-glucosidase (βG) kinetics and their temperature sensitivity (Q₁₀) were measured. The results showed that both altitude and temperature had significant effects on Cmin · Cmin increased with temperature and was highest in the B. ermanii forest. The temperature sensitivity of Cmin [Q₁₀(Cmin)] ranked in order of B. ermanii forest > P. koraiensis forest > coniferous mixed broad-leaved forest, but did not differ significantly among the three forests. Both the maximum activity (Vmax) and the Michaelis constant (Km) of the βG responded positively to temperature for all the forests. The temperature sensitivity of Vmax [Q₁₀(Vmax)] ranged from 1.78 to 1.90, and the temperature sensitivity of Km [Q₁₀(Km)] ranged from 1.79 to 2.00. The Q₁₀(Vmax)/Q10(Km) ratios were significantly greater in the B. ermanii soil than in the other two forest soils, suggesting that the βG kinetics-dependent impacts of the global warming or temperature increase on the decomposition of soil organic carbon were temperature sensitive for the forests at the higher altitudes.

Sloths like it hot: ambient temperature modulates food intake in the brown-throated sloth (Bradypus variegatus).

PubMed

Cliffe, Rebecca N; Haupt, Ryan J; Avey-Arroyo, Judy A; Wilson, Rory P

2015-01-01

Sloths are considered to have one of the lowest mass-specific metabolic rates of any mammal and, in tandem with a slow digestive rate, have been theorized to have correspondingly low rates of ingestion. Here, we show in a study conducted over five months, that three captive Bradypus variegatus (Brown-throated sloths) had a remarkably low mean food intake of 17 g kg(-1)day(-1) (SD 4.2). Food consumption was significantly affected by ambient temperature, with increased intake at higher temperatures. We suggest that the known fluctuation of sloth core body temperature with ambient temperature affects the rate at which gut fauna process digesta, allowing for increased rates of fermentation at higher temperatures. Since Bradypus sloths maintain a constantly full stomach, faster rates of fermentation should enhance digestive throughput, increasing the capacity for higher levels of food intake, thereby allowing increased energy acquisition at higher ambient temperatures. This contrasts with other mammals, which tend to show increased levels of food intake in colder conditions, and points to the importance of temperature in regulating all aspects of energy use in sloths.

Contention between supply of hydrothermal fluid and conduit obstruction: inferences from numerical simulations

NASA Astrophysics Data System (ADS)

Tanaka, Ryo; Hashimoto, Takeshi; Matsushima, Nobuo; Ishido, Tsuneo

2018-05-01

We investigate a volcanic hydrothermal system using numerical simulations, focusing on change in crater temperature. Both increases and decreases in crater temperature have been observed before phreatic eruptions. We follow the system's response for up to a decade after hydrothermal fluid flux from the deep part of the system is increased and permeability is reduced at a certain depth in a conduit. Our numerical simulations demonstrate that: (1) changes in crater temperature are controlled by the magnitude of the increase in hydrothermal fluid flux and the degree of permeability reduction; (2) significant increases in hydrothermal flux with decreases in permeability induce substantial pressure changes in shallow depths in the edifice and decreases in crater temperature; (3) the location of maximum pressure change differs between the mechanisms. The results of this study imply that it is difficult to predict eruptions by crater temperature change alone. One should be as wary of large eruptions when crater temperature decreases as when crater temperature increases. It is possible to clarify the implications of changes in crater temperature with simultaneous observation of ground deformation.[Figure not available: see fulltext.

Temperature increases on the external root surface during endodontic treatment using single file systems.

PubMed

Özkocak, I; Taşkan, M M; Gökt Rk, H; Aytac, F; Karaarslan, E Şirin

2015-01-01

The aim of this study is to evaluate increases in temperature on the external root surface during endodontic treatment with different rotary systems. Fifty human mandibular incisors with a single root canal were selected. All root canals were instrumented using a size 20 Hedstrom file, and the canals were irrigated with 5% sodium hypochlorite solution. The samples were randomly divided into the following three groups of 15 teeth: Group 1: The OneShape Endodontic File no.: 25; Group 2: The Reciproc Endodontic File no.: 25; Group 3: The WaveOne Endodontic File no.: 25. During the preparation, the temperature changes were measured in the middle third of the roots using a noncontact infrared thermometer. The temperature data were transferred from the thermometer to the computer and were observed graphically. Statistical analysis was performed using the Kruskal-Wallis analysis of variance at a significance level of 0.05. The increases in temperature caused by the OneShape file system were lower than those of the other files (P < 0.05). The WaveOne file showed the highest temperature increases. However, there were no significant differences between the Reciproc and WaveOne files. The single file rotary systems used in this study may be recommended for clinical use.

Acute effects of temperature and hypercarbia on cutaneous and branchial gas exchange in the South American lungfish, Lepidosiren paradoxa.

PubMed

Zena, Lucas A; Bícego, Kênia C; da Silva, Glauber S F; Giusti, Humberto; Glass, Mogens L; Sanchez, Adriana P

2017-01-01

The South American lungfish, Lepidosiren paradoxa inhabits seasonal environments in the Central Amazon and Paraná-Paraguay basins that undergo significant oscillations in temperature throughout the year. They rely on different gas exchange organs, such as gills and skin for aquatic gas exchange while their truly bilateral lungs are responsible for aerial gas exchange; however, there are no data available on the individual contributions of the skin and the gills to total aquatic gas exchange in L. paradoxa. Thus, in the present study we quantify the relative contributions of skin and gills on total aquatic gas exchange during warm (35°C) and cold exposure (20°C) in addition to the effects of aerial and aquatic hypercarbia on aquatic gas exchange and gill ventilation rate (f G ; 25°C), respectively. Elevated temperature (35°C) caused a significant increase in the contribution of cutaneous (from 0.61±0.13 to 1.34±0.26ml. STPD.h -1 kg -1 ) and branchial (from 0.54±0.17 to 1.73±0.53ml. STPD.h -1 kg -1 ) gas exchange for V̇CO 2 relative to the lower temperature (20°C), while V̇O 2 remained relatively unchanged. L. paradoxa exhibited a greater branchial contribution in relation to total aquatic gas exchange at lower temperatures (20 and 25°C) for oxygen uptake. Aerial hypercarbia decreased branchial V̇O 2 whereas branchial V̇CO 2 was significantly increased. Progressive increases in aquatic hypercarbia did not affect f G . This response is in contrast to increases in pulmonary ventilation that may offset any increase in arterial partial pressure of CO 2 owing to CO 2 loading through the animals' branchial surface. Thus, despite their reduced contribution to total gas exchange, cutaneous and branchial gas exchange in L. paradoxa can be significantly affected by temperature and aerial hypercarbia. Copyright © 2016 Elsevier Ltd. All rights reserved.

Trend analysis and change point detection of annual and seasonal temperature series in Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Suhaila, Jamaludin; Yusop, Zulkifli

2017-06-01

Most of the trend analysis that has been conducted has not considered the existence of a change point in the time series analysis. If these occurred, then the trend analysis will not be able to detect an obvious increasing or decreasing trend over certain parts of the time series. Furthermore, the lack of discussion on the possible factors that influenced either the decreasing or the increasing trend in the series needs to be addressed in any trend analysis. Hence, this study proposes to investigate the trends, and change point detection of mean, maximum and minimum temperature series, both annually and seasonally in Peninsular Malaysia and determine the possible factors that could contribute to the significance trends. In this study, Pettitt and sequential Mann-Kendall (SQ-MK) tests were used to examine the occurrence of any abrupt climate changes in the independent series. The analyses of the abrupt changes in temperature series suggested that most of the change points in Peninsular Malaysia were detected during the years 1996, 1997 and 1998. These detection points captured by Pettitt and SQ-MK tests are possibly related to climatic factors, such as El Niño and La Niña events. The findings also showed that the majority of the significant change points that exist in the series are related to the significant trend of the stations. Significant increasing trends of annual and seasonal mean, maximum and minimum temperatures in Peninsular Malaysia were found with a range of 2-5 °C/100 years during the last 32 years. It was observed that the magnitudes of the increasing trend in minimum temperatures were larger than the maximum temperatures for most of the studied stations, particularly at the urban stations. These increases are suspected to be linked with the effect of urban heat island other than El Niño event.

Durability of Polymer Electrolyte Membrane Fuel Cells Operated at Subfreezing Temperatures

DOE PAGES

Macauley, Natalia; Lujan, Roger W.; Spernjak, Dusan; ...

2016-09-15

The structure, composition, and interfaces of membrane electrode assemblies (MEA) and gas-diffusion layers (GDLs) have a significant effect on the performance of single-proton-exchange-membrane (PEM) fuel cells operated isothermally at subfreezing temperatures. During isothermal constant-current operation at subfreezing temperatures, water forming at the cathode initially hydrates the membrane, then forms ice in the catalyst layer and/or GDL. This ice formation results in a gradual decay in voltage. High-frequency resistance initially decreases due to an increase in membrane water content and then increases over time as the contact resistance increases. The water/ice holding capacity of a fuel cell decreases with decreasing subfreezingmore » temperature (-10°C vs. -20°C vs. -30°C) and increasing current density (0.02 A cm -2 vs. 0.04 A cm -2). Ice formation monitored using in-situ high-resolution neutron radiography indicated that the ice was concentrated near the cathode catalyst layer at low operating temperatures (≈-20°C) and high current densities (0.04 A cm -2). Significant ice formation was also observed in the GDLs at higher subfreezing temperatures (≈-10°C) and lower current densities (0.02 A cm -2). These results are in good agreement with the long-term durability observations that show more severe degradation at lower temperatures (-20°C and -30°C).« less

The Effects of Increased Body Temperature on Motor Control during Golf Putting

PubMed Central

Mathers, John F.; Grealy, Madeleine A.

2016-01-01

This study investigated the effect of increased core temperature on the performance outcome and movement kinematics of elite golfers during a golf putting task. The study aimed to examine individual differences in the extent to which increased temperature influenced the rate of putting success, whether increased temperature speeded up the timing of the putting downswing and whether elite golfers changed their movement kinematics during times of thermal stress. Six participants performed 20 putts to each of four putt distances (1, 2, 3, and 4 m) under normal temperature conditions and when core body temperature was increased. There was no significant difference in the number of successful putts between the two temperature conditions, but there was an increase in putterhead velocity at ball impact on successful putts to distances of 1 and 4 m when temperature was elevated. This reflected an increase in swing amplitude rather than a reduction in swing duration as hypothesized. There were individual differences in the motor control response to thermal stress as three of the golfers changed the kinematic parameters used to scale their putting movements to achieve putts of different distances at elevated temperatures. Theoretical implications for these findings and the practical implications for elite golfers and future research are discussed. PMID:27630588

High-Resolution Dynamical Downscaling Ensemble Projections of Future Extreme Temperature Distributions for the United States

NASA Astrophysics Data System (ADS)

Zobel, Zachary; Wang, Jiali; Wuebbles, Donald J.; Kotamarthi, V. Rao

2017-12-01

The aim of this study is to examine projections of extreme temperatures over the continental United States (CONUS) for the 21st century using an ensemble of high spatial resolution dynamically downscaled model simulations with different boundary conditions. The downscaling uses the Weather Research and Forecast model at a spatial resolution of 12 km along with outputs from three different Coupled Model Intercomparison Project Phase 5 global climate models that provide boundary conditions under two different future greenhouse gas (GHG) concentration trajectories. The results from two decadal-length time slices (2045-2054 and 2085-2094) are compared with a historical decade (1995-2004). Probability density functions of daily maximum/minimum temperatures are analyzed over seven climatologically cohesive regions of the CONUS. The impacts of different boundary conditions as well as future GHG concentrations on extreme events such as heat waves and days with temperature higher than 95°F are also investigated. The results show that the intensity of extreme warm temperature in future summer is significantly increased, while the frequency of extreme cold temperature in future winter decreases. The distribution of summer daily maximum temperature experiences a significant warm-side shift and increased variability, while the distribution of winter daily minimum temperature is projected to have a less significant warm-side shift with decreased variability. Using "business-as-usual" scenario, 5-day heat waves are projected to occur at least 5-10 times per year in most CONUS and ≥95°F days will increase by 1-2 months by the end of the century.

Temperature-dependent differences in the nonlinear acoustic behavior of ultrasound contrast agents revealed by high-speed imaging and bulk acoustics.

PubMed

Mulvana, Helen; Stride, Eleanor; Tang, Mengxing; Hajnal, Jo V; Eckersley, Robert

2011-09-01

Previous work by the authors has established that increasing the temperature of the suspending liquid from 20°C to body temperature has a significant impact on the bulk acoustic properties and stability of an ultrasound contrast agent suspension (SonoVue, Bracco Suisse SA, Manno, Lugano, Switzerland). In this paper the influence of temperature on the nonlinear behavior of microbubbles is investigated, because this is one of the most important parameters in the context of diagnostic imaging. High-speed imaging showed that raising the temperature significantly influences the dynamic behavior of individual microbubbles. At body temperature, microbubbles exhibit greater radial excursion and oscillate less spherically, with a greater incidence of jetting and gas expulsion, and therefore collapse, than they do at room temperature. Bulk acoustics revealed an associated increase in the harmonic content of the scattered signals. These findings emphasize the importance of conducting laboratory studies at body temperature if the results are to be interpreted for in vivo applications. Copyright © 2011 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Effects of humid heat exposure in later sleep segments on sleep stages and body temperature in humans

NASA Astrophysics Data System (ADS)

Okamoto-Mizuno, Kazue; Tsuzuki, Kazuyo; Mizuno, Koh

2005-03-01

This study sought to investigate the effects of humid heat exposure in later sleep segments on sleep stages and body temperature in humans. The subjects were eight healthy males, from whom informed consent had been obtained. The experiments were carried out under three different sets of conditions: a control climate [air temperature (Ta)=26°C, relative humidity (RH)=50%] (C); a humid heat climate (Ta=32°C, RH=80%) (H); and a humid heat exposure in later sleep segments (C for the first 3 h 45 min, followed by a 30-min transition to H, which was then maintained for the last 3 h 45 min) (C H). Electroencephalogram, EOG, and mental electromyogram, rectal temperature (Tre), and skin temperature (Tsk) were continuously measured. The total amount of wakefulness was significantly increased in H compared to C H or C. Compared to C, wakefulness in C H and H was significantly increased during later sleep segments. Tre and mean Tsk were significantly higher in H than in C H or C. In C H, Tsk and Tre increased to levels equal to those observed in H after Ta and RH increase. Whole body sweat loss was significantly lower in C H and C than in H. These results suggest that humid heat exposure in the later sleep segment reduces thermal load as compared to full-night humid heat exposure. In daily life, the use of air conditioning in the initial sleep hours can protect sleep and thermoregulation.

Persistent effects of incubation temperature on muscle development in larval haddock (Melanogrammus aeglefinus L.).

PubMed

Martell, D John; Kieffer, James D

2007-04-01

Muscle development and growth were investigated in haddock larvae (Melanogrammus aeglefinus L.) incubated under controlled temperatures (4, 6, 8 degrees C) and reared post-hatch through yolk-dependent and exogenous-feeding stages in a 6 degrees C post-hatch environment. Changes in cell number and size in superficial and deep myotomes within the epaxial muscle were investigated for 28 days following hatch. Distinct and significant differences in muscle cellularity following separate developmental strategies were observed in superficial and deep myotomes. The number of superficial myofibres increased with time and, although not in a manner proportional to temperature during the first 21 days post hatch (d.p.h.), there was observed a trend during the final 7 days of greater mean cell size that was strongly associated with increased temperature. In addition, there was an apparent correspondence between increased temperature and increased size between 21 and 28 d.p.h. Among all temperature groups the superficial myotome not only demonstrated a consistent unimodal myofibre-size distribution but one that increased in range proportional to temperature. In the deep muscle, myotomes from higher incubation temperatures had a broader range of fibre sizes and greater numbers of myofibres. The onset of a proliferative event, characterized by a significant recruitment of new smaller myofibres and a bimodal distribution of cell sizes, was directly proportional to incubation temperature such that it occurred at 14 d.p.h. at 8 degrees C but not until 28 d.p.h. at 4 degrees C. The magnitude of that recruitment was also directly proportional to temperature. Following hatch, those embryos from the greatest temperature groups had the largest mean deep muscle size but, as a result of the proliferative event, had the smallest-sized cells 28 days later. The muscle developmental and growth strategy as indicated by sequential changes in cellularity and cell-size distributions between myotomes in response to temperature are also discussed in light of whole animal growth and development.

Separating heat stress from moisture stress: analyzing yield response to high temperature in irrigated maize

NASA Astrophysics Data System (ADS)

Carter, Elizabeth K.; Melkonian, Jeff; Riha, Susan J.; Shaw, Stephen B.

2016-09-01

Several recent studies have indicated that high air temperatures are limiting maize (Zea mays L.) yields in the US Corn Belt and project significant yield losses with expected increases in growing season temperatures. Further work has suggested that high air temperatures are indicative of high evaporative demand, and that decreases in maize yields which correlate to high temperatures and vapor pressure deficits (VPD) likely reflect underlying soil moisture limitations. It remains unclear whether direct high temperature impacts on yields, independent of moisture stress, can be observed under current temperature regimes. Given that projected high temperature and moisture may not co-vary the same way as they have historically, quantitative analyzes of direct temperature impacts are critical for accurate yield projections and targeted mitigation strategies under shifting temperature regimes. To evaluate yield response to above optimum temperatures independent of soil moisture stress, we analyzed climate impacts on irrigated maize yields obtained from the National Corn Growers Association (NCGA) corn yield contests for Nebraska, Kansas and Missouri. In irrigated maize, we found no evidence of a direct negative impact on yield by daytime air temperature, calculated canopy temperature, or VPD when analyzed seasonally. Solar radiation was the primary yield-limiting climate variable. Our analyses suggested that elevated night temperature impacted yield by increasing rates of phenological development. High temperatures during grain-fill significantly interacted with yields, but this effect was often beneficial and included evidence of acquired thermo-tolerance. Furthermore, genetics and management—information uniquely available in the NCGA contest data—explained more yield variability than climate, and significantly modified crop response to climate. Thermo-acclimation, improved genetics and changes to management practices have the potential to partially or completely offset temperature-related yield losses in irrigated maize.

Increased Biomass Production by Mesophilic Food-Associated Bacteria through Lowering the Growth Temperature from 30°C to 10°C.

PubMed

Seel, Waldemar; Derichs, Julia; Lipski, André

2016-07-01

Five isolates from chilled food and refrigerator inner surfaces and closely related reference strains of the species Escherichia coli, Listeria monocytogenes, Staphylococcus xylosus, Bacillus cereus, Pedobacter nutrimenti, and Pedobacter panaciterrae were tested for the effect of growth temperature (30°C and 10°C) on biomass formation. Growth was monitored via optical density, and biomass formation was measured at the early stationary phase based on the following parameters in complex and defined media: viable cell count, total cell count, cell dry weight, whole-cell protein content, and cell morphology. According to the lack of growth at 1°C, all strains were assigned to the thermal class of mesophiles. Glucose and ammonium consumption related to cell yield were analyzed in defined media. Except for the protein content, temperature had a significant (t test, P < 0.05) effect on all biomass formation parameters for each strain. The results show a significant difference between the isolates and the related reference strains. Isolates achieved an increase in biomass production between 20% and 110% at the 10°C temperature, which is 15 to 25°C lower than their maximum growth rate temperatures. In contrast, reference strains showed a maximum increase of only about 25%, and some reference strains showed no increase or a decrease of approximately 25%. As expected, growth rates for all strains were higher at 30°C than at 10°C, while biomass production for isolates was higher at 10°C than at 30°C. In contrast, the reference strains showed similar growth yields at the two temperatures. This also demonstrates for mesophilic bacterial strains more efficient nutrient assimilation during growth at low temperatures. Until now, this characteristic was attributed only to psychrophilic microorganisms. For several psychrophilic species, increased biomass formation was described at temperatures lower than optimum growth temperatures, which are defined by the highest growth rate. This work shows increased biomass formation at low growth temperatures for mesophilic isolates. A comparison with closely related reference strains from culture collections showed a significantly smaller increase or no increase in biomass formation. This indicates a loss of specific adaptive mechanisms (e.g., cold adaptation) for mesophiles during long-term cultivation. The increased biomass production for mesophiles under low-temperature conditions opens new avenues for a more efficient biotechnological transformation of nutrients to microbial biomass. These findings may also be important for risk assessment of cooled foods since risk potential is often correlated with the cell numbers present in food samples. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Metabolic and cellular stress responses of catfish, Horabagrus brachysoma (Günther) acclimated to increasing temperatures.

PubMed

Dalvi, Rishikesh S; Das, Tilak; Debnath, Dipesh; Yengkokpam, Sona; Baruah, Kartik; Tiwari, Lalchand R; Pal, Asim K

2017-04-01

We investigated the metabolic and cellular stress responses in an endemic catfish Horabagrus brachysoma acclimated to ambient (26°C), 31, 33 and 36°C for 30 days. After acclimation, fish were sampled to investigate changes in the levels of blood glucose, tissue glycogen and ascorbic acid, activities of enzymes involved in glycolysis (LDH), citric acid cycle (MDH), gluconeogenesis (FBPase and G6Pase), pentose phosphate pathway (G6PDH), protein metabolism (AST and ALT), phosphate metabolism (ACP and ALP) and energy metabolism (ATPase), and HSP70 levels in various tissues. Acclimation to higher temperatures (33 and 36°C) significantly increased activities of LDH, MDH, ALP, ACP, AST, ALT and ATPase and blood glucose levels, whereas decreased the G6PDH enzyme activity and, tissue glycogen and ascorbic acid. Results indicated an overall increase in the carbohydrate, protein and lipid metabolism implying increased metabolic demands for maintaining homeostasis in fish acclimated to higher temperatures (33 and 36°C). We observed tissue specific response of HSP70 in H. brachysoma, with significant increase in gill and liver at 33 and 36°C, and in brain and muscle at 36°C, enabling cellular protection at higher acclimation temperatures. In conclusion, H. brachysoma adjusted metabolic and cellular responses to withstand increased temperatures, however, these responses suggest that the fish was under stress at 33°C or higher temperature. Copyright © 2017 Elsevier Ltd. All rights reserved.

Root surface temperature variation during mechanical removal of root canal filling material. An in vitro study.

PubMed

García-Cuerva, Martín; Horvath, Lucía; Pinasco, Laura; Ciparelli, Verónica; Gualtieri, Ariel; Casadoumecq, Ana C; Rodríguez, Pablo; Gonzalez-Zanotto, Carlos

2017-04-01

The aim of this study was to analyze in vitro temperature changes on the outer surface of the dental root during mechanical filling removal procedures. Thirty recently extracted single-rooted lower premolars were cut transversally at 16 mm from the apex in order to standardize sample length. Endodontic treatment was performed on them. The filling material was subsequently removed using Gates Glidden (G1, G2, G3); Peeso (P1, P2, P3) and PostecPlus FRC (FRC) reamers while temperatures were measured on the outer surface using a digital device with thermocouple at 0, 2, 4, 6, 8, 10 and 15 seconds. Temperatures were compared using repeated measures ANOVA followed by pairwise comparison with Tukey's test. All reamers caused significant temperature variation between different times (p<0.05). Pairwise comparisons indicated that temperature increased with time for all reamers (p<0.05). Significant differences in temperature were found between different reamers after 0, 2, 4, 6, 8,10 and 15 seconds (p<0.05). Temperature at the root surface increased considerably. Values higher than 50°C were recorded, the greatest increase from baseline being 16°C. Accordingly, if the procedure were begun at 37°C (physiological temperature), the temperature in the surrounding tissues - cementum, periodontium and bone - would rise to 53°C. An increase in 10°C above body temperature at the root surface may cause lesions in surrounding tissues. While removing filling material, it is essential to cool, control action time and use instruments in perfect condition, all of which may contribute to reducing the heat generated and transmitted to the outer root surface. Sociedad Argentina de Pediatría.

A large change in temperature between neighbouring days increases the risk of mortality.

PubMed

Guo, Yuming; Barnett, Adrian G; Yu, Weiwei; Pan, Xiaochuan; Ye, Xiaofang; Huang, Cunrui; Tong, Shilu

2011-02-02

Previous studies have found high temperatures increase the risk of mortality in summer. However, little is known about whether a sharp decrease or increase in temperature between neighbouring days has any effect on mortality. Poisson regression models were used to estimate the association between temperature change and mortality in summer in Brisbane, Australia during 1996-2004 and Los Angeles, United States during 1987-2000. The temperature change was calculated as the current day's mean temperature minus the previous day's mean. In Brisbane, a drop of more than 3 °C in temperature between days was associated with relative risks (RRs) of 1.157 (95% confidence interval (CI): 1.024, 1.307) for total non-external mortality (NEM), 1.186 (95%CI: 1.002, 1.405) for NEM in females, and 1.442 (95%CI: 1.099, 1.892) for people aged 65-74 years. An increase of more than 3 °C was associated with RRs of 1.353 (95%CI: 1.033, 1.772) for cardiovascular mortality and 1.667 (95%CI: 1.146, 2.425) for people aged <65 years. In Los Angeles, only a drop of more than 3 °C was significantly associated with RRs of 1.133 (95%CI: 1.053, 1.219) for total NEM, 1.252 (95%CI: 1.131, 1.386) for cardiovascular mortality, and 1.254 (95%CI: 1.135, 1.385) for people aged ≥ 75 years. In both cities, there were joint effects of temperature change and mean temperature on NEM. A significant change in temperature of more than 3 °C, whether positive or negative, has an adverse impact on mortality even after controlling for the current temperature.

Extreme temperature trends in major cropping systems and their relation to agricultural land use change

NASA Astrophysics Data System (ADS)

Mueller, N. D.; Butler, E. E.; McKinnon, K. A.; Rhines, A. N.; Tingley, M.; Siebert, S.; Holbrook, N. M.; Huybers, P. J.

2015-12-01

High temperature extremes during the growing season can reduce agricultural production. At the same time, agricultural practices can modify temperatures by altering the surface energy budget. Here we investigate growing season climate trends in major cropping systems and their relationship with agricultural land use change. In the US Midwest, 100-year trends exhibit a transition towards more favorable conditions, with cooler summer temperature extremes and increased precipitation. Statistically significant correspondence is found between the cooling pattern and trends in cropland intensification, as well as with trends towards greater irrigated land over a small subset of the domain. Land conversion to cropland, often considered an important influence on historical temperatures, is not significantly associated with cooling. We suggest that cooling is primarily associated with agricultural intensification increasing the potential for evapotranspiration, consistent with our finding that cooling trends are greatest for the highest temperature percentiles, and that increased evapotranspiration generally leads to greater precipitation. Temperatures over rainfed croplands show no cooling trend during drought conditions, consistent with evapotranspiration requiring adequate soil moisture, and implying that modern drought events feature greater warming as baseline cooler temperatures revert to historically high extremes. Preliminary results indicate these relationships between temperature extremes, irrigation, and intensification are also observed in other major summer cropping systems, including northeast China, Argentina, and the Canadian Prairies.

Cold Temperatures Increase Cold Hardiness in the Next Generation Ophraella communa Beetles

PubMed Central

Zhou, Zhong-Shi; Rasmann, Sergio; Li, Min; Guo, Jian-Ying; Chen, Hong-Song; Wan, Fang-Hao

2013-01-01

The leaf beetle, Ophraella communa, has been introduced to control the spread of the common ragweed, Ambrosia artemisiifolia, in China. We hypothesized that the beetle, to be able to track host-range expansion into colder climates, can phenotypically adapt to cold temperatures across generations. Therefore, we questioned whether parental experience of colder temperatures increases cold tolerance of the progeny. Specifically, we studied the demography, including development, fecundity, and survival, as well as physiological traits, including supercooling point (SCP), water content, and glycerol content of O. communa progeny whose parents were maintained at different temperature regimes. Overall, the entire immature stage decreased survival of about 0.2%–4.2% when parents experienced cold temperatures compared to control individuals obtained from parents raised at room temperature. However, intrinsic capacity for increase (r), net reproductive rate (R 0) and finite rate of increase (λ) of progeny O. communa were maximum when parents experienced cold temperatures. Glycerol contents of both female and male in progeny was significantly higher when maternal and paternal adults were cold acclimated as compared to other treatments. This resulted in the supercooling point of the progeny adults being significantly lower compared to beetles emerging from parents that experienced room temperatures. These results suggest that cold hardiness of O. communa can be promoted by cold acclimation in previous generation, and it might counter-balance reduced survival in the next generation, especially when insects are tracking their host-plants into colder climates. PMID:24098666

Trends and variability of daily temperature and precipitation extremes during 1960-2012 in the Yangtze River Basin, China

NASA Astrophysics Data System (ADS)

Guan, Yinghui

2017-04-01

The variability of surface air temperature and precipitation extremes has been the focus of attention during the past several decades, and may exert a great influence on the global hydrologic cycle and energy balance through thermal forcing. Using daily minimum (TN), maximum temperature (TX) and precipitation　from 143 meteorological stations in the Yangtze River Basin (YRB), a suite of extreme climate indices recommended by the Expert Team on Climate Change Detection and Indices, which has rarely been applied in this region, were computed and analyzed during 1960-2012. The results show widespread significant changes in all temperature indices associated with warming in the YRB during 1960-2012. On the whole, cold-related indices, i.e., cold nights, cold days, frost days, icing days and cold spell duration index significantly decreased by -3.45, -1.03, -3.04, -0.42 and -1.6 days/decade, respectively. In contrast, warm-related indices such as warm nights, warm days, summer days, tropical nights and warm spell duration index significantly increased by 2.95, 1.71, 2.16, 1.05 and 0.73 days/decade. Minimum TN, maximum TN, minimum TX and maximum TX increased significantly by 0.42, 0.18, 0.19 and 0.14 °C/decade. Because of a faster increase in minimum temperature than maximum temperature, the diurnal temperature range (DTR) exhibited a significant decreasing trend of -0.09 °C/decade for the whole YRB during 1960-2012. Geographically, stations in the eastern Tibet Plateau and northeastern YRB showed stronger trends in almost all temperature indices. Time series analysis indicated that the YRB was dominated by a general cooling trend before the mid-1980s, but a warming trend afterwards. For precipitation, simple daily intensity index, very wet day precipitation, extremely wet day precipitation, extremely heavy precipitation days, maximum 1-day precipitation, maximum 5-day precipitation and maximum consecutive dry days all increased significantly during 1960-2012. In contrast, ≥ 10 mm precipitation days and maximum consecutive wet days decreased significantly, implying that the precipitation processes in YRB were dominated by precipitation events with shorter durations. Geographically, a wetting tendency was observed in the eastern Tibet Plateau and the middle and lower YRB, while the other regions experienced precipitation deficits. The increasing precipitation was mainly due to the intensification of extreme precipitation events and the decreasing precipitation may be attributed to the decrease of ≥ 10 mm precipitation days or moderate precipitation events. In addition, the regional trends were of greater magnitudes in the middle and lower YRB, indicating more frequent extreme precipitation events in these sub-regions.

Influence of temperature changes on migraine occurrence in Germany

NASA Astrophysics Data System (ADS)

Scheidt, Jörg; Koppe, Christina; Rill, Sven; Reinel, Dirk; Wogenstein, Florian; Drescher, Johannes

2013-07-01

Many factors trigger migraine attacks. Weather is often reported to be one of the most common migraine triggers. However, there is little scientific evidence about the underlying mechanisms and causes. In our pilot study, we used smartphone apps and a web form to collect around 4,700 migraine messages in Germany between June 2011 and February 2012. Taking interdiurnal temperature changes as an indicator for changes in the prevailing meteorological conditions, our analyses were focused on the relationship between temperature changes and the frequency of occurrence of migraine attacks. Linear trends were fitted to the total number of migraine messages with respect to temperature changes. Statistical and systematic errors were estimated. Both increases and decreases in temperature lead to a significant increase in the number of migraine messages. A temperature increase (decrease) of 5 °C resulted in an increase of 19 ± 7 % (24 ± 8 %) in the number of migraine messages.

Asymmetry of projected increases in extreme temperature distributions

PubMed Central

Kodra, Evan; Ganguly, Auroop R.

2014-01-01

A statistical analysis reveals projections of consistently larger increases in the highest percentiles of summer and winter temperature maxima and minima versus the respective lowest percentiles, resulting in a wider range of temperature extremes in the future. These asymmetric changes in tail distributions of temperature appear robust when explored through 14 CMIP5 climate models and three reanalysis datasets. Asymmetry of projected increases in temperature extremes generalizes widely. Magnitude of the projected asymmetry depends significantly on region, season, land-ocean contrast, and climate model variability as well as whether the extremes of consideration are seasonal minima or maxima events. An assessment of potential physical mechanisms provides support for asymmetric tail increases and hence wider temperature extremes ranges, especially for northern winter extremes. These results offer statistically grounded perspectives on projected changes in the IPCC-recommended extremes indices relevant for impacts and adaptation studies. PMID:25073751

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

PubMed

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

2018-07-01

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

Projection of future temperature-related mortality due to climate and demographic changes.

PubMed

Lee, Jae Young; Kim, Ho

2016-09-01

Understanding the effects of global climate change from both environmental and human health perspectives has gained great importance. Particularly, studies on the direct effect of temperature increase on future mortality have been conducted. However, few of those studies considered population changes, and although the world population is rapidly aging, no previous study considered the effect of society aging. Here we present a projection of future temperature-related mortality due to both climate and demographic changes in seven major cities of South Korea, a fast aging country, until 2100; we used the HadGEM3-RA model under four Representative Concentration Pathway (RCP) scenarios (RCP 2.6, 4.5, 6.0, and 8.5) and the United Nations world population prospects under three fertility scenarios (high, medium, and low). The results showed markedly increased mortality in the elderly group, significantly increasing the overall future mortality. In 2090s, South Korea could experience a four- to six-time increase in temperature-related mortality compared to that during 1992-2010 under four different RCP scenarios and three different fertility variants, while the mortality is estimated to increase only by 0.5 to 1.5 times assuming no population aging. Therefore, not considering population aging may significantly underestimate temperature risks. Copyright © 2016 Elsevier Ltd. All rights reserved.

Changes in the physiological parameters, fatty acid metabolism, and SCD activity and expression in juvenile GIFT tilapia (Oreochromis niloticus) reared at three different temperatures.

PubMed

Ma, X Y; Qiang, J; He, J; Gabriel, N N; Xu, P

2015-08-01

We evaluated the effects of rearing temperature on the composition of fatty acids and stearoyl-CoA desaturase (SCD) activity and gene expression in GIFT (genetically improved farmed tilapia) tilapia. Three triplicate groups of fish were reared for 40 days at 22, 28, or 34 °C. At the end of the trial, the final body weight of juveniles reared at 28 °C was higher than that of fish reared at 22 or 34 °C. Feed intake, feed efficiency, and the protein efficiency ratio were also higher at 28 °C. The fatty acid composition of muscle tissue differed significantly (P < 0.05) among the treatment groups. The content of SFA decreased with decreasing temperature, whereas the UFA content increased. We observed high levels of PUFA, particularly n-3 PUFAs, in fish reared at the lower temperature. Rearing at low temperature significantly (P < 0.05) increased the expression and activity of the SCD gene. Increased SCD activity and gene expression can increase the biosynthesis of MUFAs in GIFT tilapia muscle. Additionally, cold acclimation can decrease the content of TC and TG in GIFT tilapia, which can help increase cold tolerance.

Increased nitrogen availability counteracts climatic change feedback from increased temperature on boreal forest soil organic matter degradation

NASA Astrophysics Data System (ADS)

Erhagen, Bjorn; Nilsson, Mats; Oquist, Mats; Ilstedt, Ulrik; Sparrman, Tobias; Schleucher, Jurgen

2014-05-01

Over the last century, the greenhouse gas concentrations in the atmosphere have increased dramatically, greatly exceeding pre-industrial levels that had prevailed for the preceding 420 000 years. At the same time the annual anthropogenic contribution to the global terrestrial nitrogen cycle has increased and currently exceeds natural inputs. Both temperature and nitrogen levels have profound effects on the global carbon cycle including the rate of organic matter decomposition, which is the most important biogeochemical process that returns CO2 to the atmosphere. Here we show for the first time that increasing the availability of nitrogen not only directly affects the rate of organic matter decomposition but also significantly affects its temperature dependence. We incubated litter and soil organic matter from a long-term (40 years) nitrogen fertilization experiment in a boreal Scots pine (Pinus silvestris L.) forest at different temperatures and determined the temperature dependence of the decomposition of the sample's organic matter in each case. Nitrogen fertilization did not affect the temperature sensitivity (Q10) of the decomposition of fresh plant litter but strongly reduced that for humus soil organic matter. The Q10 response of the 0-3 cm soil layer decreased from 2.5±0.35 to an average of 1.9±0.21 over all nitrogen treatments, and from 2.2±0.19 to 1.6±0.16 in response to the most intense nitrogen fertilization treatment in the 4-7 cm soil layer. Long-term nitrogen additions also significantly affected the organic chemical composition (as determined by 13C CP-MAS NMR spectroscopy) of the soil organic matter. These changes in chemical composition contributed significantly (p<0.05) to the reduced Q10 response. These new insights into the relationship between nitrogen availability and the temperature sensitivity of organic matter decomposition will be important for understanding and predicting how increases in global temperature and rising anthropogenic nitrogen inputs will affect the global carbon cycle and the associated climatic feedback processes.

[Properties of maize stalk biochar produced under different pyrolysis temperatures and its sorption capability to naphthalene].

PubMed

Huang, Hua; Wang, Ya-Xiong; Tang, Jing-Chun; Tang, Jing-Chun; Zhu, Wen-Ying

2014-05-01

Biochar was made from maize stalk under three different temperatures of 300, 500 and 700 degreeC. The elemental composition of biochar was measured by elemental analyzer. Scanning electron microscope (SEM) was used to measure the surface morphology. Sorption of naphthalene to biochar was researched by batch sorption experiments. Results showed that, with the increase of temperature, C content increased from 66. 79% to 76. 30% , H and O contents decreased from 4.92% and 19. 25% to 3. 18% and 9.53%, respectively; H/C, O/C, (O + N)/C, aromaticity and hydrophobicity increased, and polarity decreased. SEM results showed that maize stalk biochar was platy particles, and its roughness of surface increased with increasing temperature. The sorption of naphthalene on biochar followed the Lagergren pseudo-second order dynamic sorption model. Initial sorption rate and equilibrium sorption capacity increased as preparation temperatures increased at the same initial concentration of naphthalene. The isotherm sorption behavior can be described by the Freundlich model, which indicated that, as pyrolysis temperature increased, the sorption capacity of biochar increased, and nonlinearity increased first and then decreased. Biochar derived from maize stalk had distinct features when compared with other feedstocks, and its elemental composition, surface features and sorption behaviors were significantly influenced by pyrolysis temperature.

Determination and error analysis of emittance and spectral emittance measurements by remote sensing

NASA Technical Reports Server (NTRS)

Dejesusparada, N. (Principal Investigator); Kumar, R.

1977-01-01

The author has identified the following significant results. From the theory of remote sensing of surface temperatures, an equation of the upper bound of absolute error of emittance was determined. It showed that the absolute error decreased with an increase in contact temperature, whereas, it increased with an increase in environmental integrated radiant flux density. Change in emittance had little effect on the absolute error. A plot of the difference between temperature and band radiance temperature vs. emittance was provided for the wavelength intervals: 4.5 to 5.5 microns, 8 to 13.5 microns, and 10.2 to 12.5 microns.

Strong temperature effect on the sizes of the Cooper pairs in a two-band superconductor

NASA Astrophysics Data System (ADS)

Örd, Teet; Rägo, Küllike; Vargunin, Artjom; Litak, Grzegorz

2018-01-01

We study the temperature dependencies of the mean sizes of the Cooper pairs in a two-band BCS-type s-wave superconductivity model with coupling cut-off in the momentum space. It is found that, in contrast to single-band systems, the size of Cooper pairs in the weaker superconductivity band can significantly decrease with a temperature increase due to an interband proximity effect. The relevant spatial behaviour of the wave functions of the Cooper pairs is analyzed. The results also indicate a possibility that the size of Cooper pairs in two-band systems may increase with an increase in temperature.

Hemodynamic and thermoregulatory responses to lower body water immersion.

PubMed

Muller, Matthew D; Kim, Cihul-Ho; Seo, Yongsuk; Ryan, Edward J; Glickman, Ellen L

2012-10-01

Lower body water immersion (LBWI) is experienced in the marine industry but the physiological responses to LBWI are unclear. The purpose of the current experiment was to test the effects of water temperature and immersion duration on rectal temperature, heart rate, stroke volume, blood pressure, metabolic rate, and thermal sensation in healthy subjects. Nine young men underwent two 60-min trials of seated LBWI to the iliac crest in a counterbalanced fashion. On one occasion, the water was 35 degrees C (LBWI-Neutral) and on the other it was 13 degrees C (LBWI-Cold); the upper body remained thermoneutral and dry throughout. As expected, exposure to cold water reduced mean skin temperature and individuals reported cold thermal sensation. Mean arterial pressure was significantly higher at 60 min of LBWI-Cold (86 +/- 7 mmHg) compared to LBWI-Neutral (76 +/- 5 mmHg) while heart rate tended to be lower. The change in rectal temperature from baseline to 30 min of LBWI-Cold (delta = -0.01 +/- 0.21degrees C) was significantly smaller than the change in T(re) from 30 to 60 min of LBWI-Cold (delta = -0.46 +/- 0.16 degrees C). Despite this accelerated drop in core temperature during minutes 30-60, metabolic rate did not increase significantly. LBWI-Cold reduces core temperature and increases arterial blood pressure via an increase in total peripheral resistance. This experimental model may help scientists better understand the body during cold stress. Further, people who are occupationally exposed to cold water (when the torso, hands, and arms remain thermoneutral) may be at increased risk for hypothermia.

Response of Nitrosospira sp. strain AF-like ammonia oxidizers to changes in temperature, soil moisture content, and fertilizer concentration.

PubMed

Avrahami, Sharon; Bohannan, Brendan J M

2007-02-01

Very little is known regarding the ecology of Nitrosospira sp. strain AF-like bacteria, a unique group of ammonia oxidizers within the Betaproteobacteria. We studied the response of Nitrosospira sp. strain AF-like ammonia oxidizers to changing environmental conditions by applying molecular methods and physiological measurements to Californian grassland soil manipulated in the laboratory. This soil is naturally high in Nitrosospira sp. strain AF-like bacteria relative to the much-better-studied Nitrosospira multiformis-like ammonia-oxidizing bacteria. Increases in temperature, soil moisture, and fertilizer interacted to reduce the relative abundance of Nitrosospira sp. strain AF-like bacteria, although they remained numerically dominant. The overall abundance of ammonia-oxidizing bacteria increased with increasing soil moisture and decreased with increasing temperature. Potential nitrification activity was altered by interactions among temperature, soil moisture, and fertilizer, with activity tending to be higher when soil moisture and temperature were increased. The increase in potential nitrification activity with increased temperature was surprising, given that the overall abundance of ammonia-oxidizing bacteria decreased significantly under these conditions. This observation suggests that (i) Nitrosospira sp. strain AF-like bacteria may respond to increased temperature with an increase in activity, despite a decrease in abundance, or (ii) that potential nitrification activity in these soils may be due to organisms other than bacteria (e.g., archaeal ammonia oxidizers), at least under conditions of increased temperature.

Response of Nitrosospira sp. Strain AF-Like Ammonia Oxidizers to Changes in Temperature, Soil Moisture Content, and Fertilizer Concentration▿

PubMed Central

Avrahami, Sharon; Bohannan, Brendan J. M.

2007-01-01

Very little is known regarding the ecology of Nitrosospira sp. strain AF-like bacteria, a unique group of ammonia oxidizers within the Betaproteobacteria. We studied the response of Nitrosospira sp. strain AF-like ammonia oxidizers to changing environmental conditions by applying molecular methods and physiological measurements to Californian grassland soil manipulated in the laboratory. This soil is naturally high in Nitrosospira sp. strain AF-like bacteria relative to the much-better-studied Nitrosospira multiformis-like ammonia-oxidizing bacteria. Increases in temperature, soil moisture, and fertilizer interacted to reduce the relative abundance of Nitrosospira sp. strain AF-like bacteria, although they remained numerically dominant. The overall abundance of ammonia-oxidizing bacteria increased with increasing soil moisture and decreased with increasing temperature. Potential nitrification activity was altered by interactions among temperature, soil moisture, and fertilizer, with activity tending to be higher when soil moisture and temperature were increased. The increase in potential nitrification activity with increased temperature was surprising, given that the overall abundance of ammonia-oxidizing bacteria decreased significantly under these conditions. This observation suggests that (i) Nitrosospira sp. strain AF-like bacteria may respond to increased temperature with an increase in activity, despite a decrease in abundance, or (ii) that potential nitrification activity in these soils may be due to organisms other than bacteria (e.g., archaeal ammonia oxidizers), at least under conditions of increased temperature. PMID:17158615

Augmentation of blood circulation to the fingers by warming distant body areas

NASA Technical Reports Server (NTRS)

Koscheyev, V. S.; Leon, G. R.; Paul, S.; Tranchida, D.; Linder, I. V.

2000-01-01

Future activities in space will require greater periods of time in extreme environments in which the body periphery will be vulnerable to chilling. Maintaining the hands and fingers in comfortable conditions enhances finger flexibility and dexterity, and thus effects better work performance. We have evaluated the efficacy of promoting heat transfer and release by the extremities by increasing the blood flow to the periphery from more distant parts of the body. The experimental garment paradigm developed by the investigators was used to manipulate the temperature of different body areas. Six subjects, two females and four males, were evaluated in a stage-1 baseline condition, with the inlet temperature of the circulating water in the liquid cooling/warming garment (LCWG) at 33 degrees C. At stage 2 the total LCWG water inlet temperature was cooled to 8 degrees C, and at stage 3 the inlet water temperature in specific segments of the LCWG was warmed (according to protocol) to 45 degrees C, while the inlet temperature in the rest of the LCWG was maintained at 8 degrees C. The following four body-area-warming conditions were studied in separate sessions: (1) head, (2) upper torso/arm, (3) upper torso/arm/head, and (4) legs/feet. Skin temperature, heat flux and blood perfusion of the fingers, and subjective perception of thermal sensations and overall physical comfort were assessed. Finger temperature (T(fing)) analyses showed a statistically significant condition x stage interaction. Post-hoc comparisons (T(fing)) indicated that at stage 3, the upper torso/arm/head warming condition was significantly different from the head, upper torso/arm and legs/feet conditions, showing an increase in T(fing). There was a significant increase in blood perfusion in the fingers at stage 3 in all conditions. Subjective perception of hand warmth, and overall physical comfort level significantly increased in the stage 3 upper torso/arm/head condition. The findings indicate that physiological methods to enhance heat transfer by the blood to the periphery within protective clothing provide an additional tool for increasing total and local human comfort in extreme environments.

Visualization techniques to experimentally model flow and heat transfer in turbine and aircraft flow passages

NASA Technical Reports Server (NTRS)

Russell, Louis M.; Hippensteele, Steven A.

1991-01-01

Increased attention to fuel economy and increased thrust requirements have increased the demand for higher aircraft gas turbine engine efficiency through the use of higher turbine inlet temperatures. These higher temperatures increase the importance of understanding the heat transfer patterns which occur throughout the turbine passages. It is often necessary to use a special coating or some form of cooling to maintain metal temperatures at a level which the metal can withstand for long periods of time. Effective cooling schemes can result in significant fuel savings through higher allowable turbine inlet temperatures and can increase engine life. Before proceeding with the development of any new turbine it is economically desirable to create both mathematical and experimental models to study and predict flow characteristics and temperature distributions. Some of the methods are described used to physically model heat transfer patterns, cooling schemes, and other complex flow patterns associated with turbine and aircraft passages.

Effect of Heat-Treatment Temperature on the Interfacial Reaction Between Oxide Inclusions and Si-Mn Killed Steel

NASA Astrophysics Data System (ADS)

Zhang, Xueliang; Yang, Shufeng; Liu, Chengsong; Li, Jingshe; Hao, Weixing

2018-06-01

The effect of heat-treatment temperature on the interfacial reaction between MnO-SiO2-FeO oxide and Fe-Mn-Si alloy was investigated by the diffusion couple method in the temperature range of 1173-1573 K. The reaction at the interface between the alloy and oxide was not obvious during treatment at 1173 K, but, with increasing heat-treatment temperature, the interfacial reaction was strengthened and the proportion of the MnO·SiO2 phase in the oxide increased. The width of the particle-precipitation zone in the alloy increased with increasing temperature from 1173 K to 1473 K but decreased at 1573 K owing to coarsening of the precipitated particles. In addition, Mn2+ and Si4+ in the oxide significantly diffused into the alloy at 1573 K, resulting in an obvious increase of the Mn and Si contents in the alloy near the interface.

Performance of three systems for warming intravenous fluids at different flow rates.

PubMed

Satoh, J; Yamakage, M; Wasaki, S I; Namiki, A

2006-02-01

This study compared the intravenous fluid warming capabilities of three systems at different flow rates. The devices studied were a water-bath warmer, a dry-heat plate warmer, and an intravenous fluid tube warmer Ambient temperature was controlled at 22 degrees to 24 degrees C. Normal saline (0.9% NaCl) at either room temperature (21 degrees to 23 degrees C) or at ice-cold temperature (3 degrees to 5 degrees C) was administered through each device at a range of flow rates (2 to 100 ml/min). To mimic clinical conditions, the temperature of the fluid was measured with thermocouples at the end of a one metre tube connected to the outflow of the warmer for the first two devices and at the end of the 1.2 m warming tubing for the intravenous fluid tube warmer The temperature of fluid delivered by the water bath warmer increased as the flow rate was increased up to 15 to 20 ml/min but decreased with greater flow rates. The temperature of the fluid delivered by the dry-heat plate warmer significantly increased as the flow rate was increased within the range tested (due to decreased cooling after leaving the device at higher flow rates). The temperature of fluid delivered by the intravenous fluid tube warmer did not depend on the flow rate up to 20 ml/min but significantly and fluid temperature-dependently decreased at higher flow rates (>30 ml/min). Under the conditions of our testing, the dry heat plate warmer delivered the highest temperature fluid at high flow rates.

Microinjection of muscimol into caudal periaqueductal gray lowers body temperature and attenuates increases in temperature and activity evoked from the dorsomedial hypothalamus.

PubMed

de Menezes, Rodrigo C A; Zaretsky, Dmitry V; Fontes, Marco A P; DiMicco, Joseph A

2006-05-30

Microinjection of the neuronal inhibitor muscimol into the midbrain lateral/dorsolateral periaqueductal gray (l/dlPAG) suppresses increases in heart rate (HR) and mean arterial pressure (MAP) evoked by microinjection of the GABA(A) receptor antagonist bicuculline methiodide (BMI) into the dorsomedial hypothalamus (DMH) in rats. Injection of BMI into the DMH also increases body temperature (Tco) and motor activity. Here, our goal was to extend previous findings by examining the effect of microinjection of muscimol into the PAG on these thermogenic and behavioral responses in conscious freely moving rats. Microinjection of muscimol (300 pmol and 1 nmol) alone into the l/dlPAG reduced baseline Tco without affecting activity, HR, or MAP. Similar injection of a dose that failed to alter baseline Tco (100 pmol) suppressed the increases in Tco evoked from the DMH and significantly attenuated DMH-induced increases in locomotor activity. Whereas microinjection of 1 nmol muscimol into the ldlPAG abolished the increases in Tco evoked from the DMH and in fact lowered body temperature to a degree similar to that seen after this dose of muscimol alone, 1 nmol muscimol at adjacent sites outside the targeted region of the PAG had no significant effect on DMH-induced increases in Tco or any other parameter. These results indicate a role for neuronal activity in the l/dlPAG in (1) the temperature and behavioral responses to disinhibition of neurons in the DMH, and (2) the maintenance of basal body temperature in conscious freely moving rats.

Associations between Temperature and Hospital Admissions for Subarachnoid Hemorrhage in Korea

PubMed Central

Lee, Suji; Guth, Matthias

2017-01-01

The relationship between temperature and subarachnoid hemorrhage (SAH) is less studied than that between temperature and myocardial infarction or other cardiovascular diseases. This study investigated the association between daily temperature and risk of SAH by analyzing the hospital admission records of 111,316 SAH patients from 2004 to 2012 in Korea. A Poisson regression model was used to examine the association between temperature and daily SAH hospital admissions. To analyze data and identify vulnerable groups, we used the following subgroups: sex, age, insurance type, area (rural or urban), and different climate zones. We confirmed a markedly higher SAH risk only for people of low socioeconomic status in both hot and cold temperatures; the relative risk (RR) in the Medicaid group was significantly increased and ranged from 1.04 to 1.11 for cold temperatures and 1.10 to 1.11 for hot temperatures. For the National Health Insurance group, the RR was increased to 1.02 for the maximum temperature only. The increased risk for SAH was highest in the temperate zone. An increase above the heat threshold temperature and a decrease below the cold threshold temperature were correlated with an increased risk of SAH in susceptible populations and were associated with different lag effects and RRs. PMID:28430143

Impacts of temperature and its variability on mortality in New England

NASA Astrophysics Data System (ADS)

Shi, Liuhua; Kloog, Itai; Zanobetti, Antonella; Liu, Pengfei; Schwartz, Joel D.

2015-11-01

Rapid build-up of greenhouse gases is expected to increase Earth’s mean surface temperature, with unclear effects on temperature variability. This makes understanding the direct effects of a changing climate on human health more urgent. However, the effects of prolonged exposures to variable temperatures, which are important for understanding the public health burden, are unclear. Here we demonstrate that long-term survival was significantly associated with both seasonal mean values and standard deviations of temperature among the Medicare population (aged 65+) in New England, and break that down into long-term contrasts between ZIP codes and annual anomalies. A rise in summer mean temperature of 1 °C was associated with a 1.0% higher death rate, whereas an increase in winter mean temperature corresponded to a 0.6% decrease in mortality. Increases in standard deviations of temperature for both summer and winter were harmful. The increased mortality in warmer summers was entirely due to anomalies, whereas it was long-term average differences in the standard deviation of summer temperatures across ZIP codes that drove the increased risk. For future climate scenarios, seasonal mean temperatures may in part account for the public health burden, but the excess public health risk of climate change may also stem from changes of within-season temperature variability.

Climate trends and projections for the Andean Altiplano and strategies for adaptation

NASA Astrophysics Data System (ADS)

Valdivia, C.; Thibeault, J.; Gilles, J. L.; García, M.; Seth, A.

2013-04-01

Climate variability and change impact production in rainfed agricultural systems of the Bolivian highlands. Maximum temperature trends are increasing for the Altiplano. Minimum temperature increases are significant in the northern region, and decreases are significant in the southern region. Producers' perceptions of climate hazards are high in the central region, while concerns with changing climate and unemployment are high in the north. Similar high-risk perceptions involve pests and diseases in both regions. Altiplano climate projections for end-of-century highlights include increases in temperature, extreme event frequency, change in the timing of rainfall, and reduction of soil humidity. Successful adaptation to these changes will require the development of links between the knowledge systems of producers and scientists. Two-way participatory approaches to develop capacity and information that involve decision makers and scientists are appropriate approaches in this context of increased risk, uncertainty and vulnerability.

The impact of individual and combined abiotic factors on daily otolith growth in a coral reef fish

NASA Astrophysics Data System (ADS)

Wenger, Amelia S.; Whinney, James; Taylor, Brett; Kroon, Frederieke

2016-06-01

Coral reefs are increasingly subjected to both local and global stressors, however, there is limited information on how reef organisms respond to their combined effects under natural conditions. This field study examined the growth response of the damselfish Neopomacentrus bankieri to the individual and combined effects of multiple abiotic factors. Turbidity, temperature, tidal movement, and wave action were recorded every 10 minutes for four months, after which the daily otolith growth of N. bankieri was aligned with corresponding abiotic conditions. Temperature was the only significant driver of daily otolith increment width, with increasing temperatures resulting in decreasing width. Although tidal movement was not a significant driver of increment width by itself, the combined effect of tidal movement and temperature had a greater negative effect on growth than temperature alone. Our results indicate that temperature can drive changes in growth even at very fine scales, and demonstrate that the cumulative impact of abiotic factors can be substantially greater than individual effects. As abiotic factors continue to change in intensity and duration, the combined impacts of them will become increasingly important drivers of physiological and ecological change.

The impact of individual and combined abiotic factors on daily otolith growth in a coral reef fish.

PubMed

Wenger, Amelia S; Whinney, James; Taylor, Brett; Kroon, Frederieke

2016-06-28

Coral reefs are increasingly subjected to both local and global stressors, however, there is limited information on how reef organisms respond to their combined effects under natural conditions. This field study examined the growth response of the damselfish Neopomacentrus bankieri to the individual and combined effects of multiple abiotic factors. Turbidity, temperature, tidal movement, and wave action were recorded every 10 minutes for four months, after which the daily otolith growth of N. bankieri was aligned with corresponding abiotic conditions. Temperature was the only significant driver of daily otolith increment width, with increasing temperatures resulting in decreasing width. Although tidal movement was not a significant driver of increment width by itself, the combined effect of tidal movement and temperature had a greater negative effect on growth than temperature alone. Our results indicate that temperature can drive changes in growth even at very fine scales, and demonstrate that the cumulative impact of abiotic factors can be substantially greater than individual effects. As abiotic factors continue to change in intensity and duration, the combined impacts of them will become increasingly important drivers of physiological and ecological change.

The impact of individual and combined abiotic factors on daily otolith growth in a coral reef fish

PubMed Central

Wenger, Amelia S.; Whinney, James; Taylor, Brett; Kroon, Frederieke

2016-01-01

Coral reefs are increasingly subjected to both local and global stressors, however, there is limited information on how reef organisms respond to their combined effects under natural conditions. This field study examined the growth response of the damselfish Neopomacentrus bankieri to the individual and combined effects of multiple abiotic factors. Turbidity, temperature, tidal movement, and wave action were recorded every 10 minutes for four months, after which the daily otolith growth of N. bankieri was aligned with corresponding abiotic conditions. Temperature was the only significant driver of daily otolith increment width, with increasing temperatures resulting in decreasing width. Although tidal movement was not a significant driver of increment width by itself, the combined effect of tidal movement and temperature had a greater negative effect on growth than temperature alone. Our results indicate that temperature can drive changes in growth even at very fine scales, and demonstrate that the cumulative impact of abiotic factors can be substantially greater than individual effects. As abiotic factors continue to change in intensity and duration, the combined impacts of them will become increasingly important drivers of physiological and ecological change. PMID:27350589

[Clinical significance of peak body temperature, white blood cell count, and C-reactive protein level in febrile episodes among geriatric inpatients].

PubMed

Ikematsu, H; Nabeshima, A; Yamaga, S; Yamaji, K; Kakuda, K; Ueno, K; Hayashi, J; Shirai, T; Hara, H; Kashiwagi, S

1997-06-01

To investigate the clinical implication of peak body temperature, peripheral blood white blood cell (WBC) count, and serum C-reactive protein (CRP) level in febrile symptoms among geriatric hospitalized patients, they were analyzed in 968 febrile episodes obtained from 433 hospitalized patients in the referred hospital. Episodes of one day duration were most frequent (41.6%). WBC count was elevated over 8000/microliters in 475 episodes (49.1%) and CRP exceeded 1.0 mg/dl in 770 episodes (79.5%). Frequency of WBC elevation decreased and frequency of CRP elevation increased according to the time course. The mean value of CRP increased significantly according to the time course. The frequency of WBC count increase and CRP elevation and their averages correlated to the peak body temperature. The peak body temperature displayed the most striking correlation to the length of febrile episodes among three clinical indicators, peak body temperature, WBC count, and CRP level. These results indicate that the elevation of WBC count and/or CRP level is frequent in geriatric patients with febrile symptoms. Peak body temperature may serve as a clinical indicator of the severy of the febrile disease occurring in geriatric patients.

Impact Assessment of Global Temperature Perturbations on Urban and Regional Ozone Levels in South Texas

NASA Astrophysics Data System (ADS)

Biswas, Jhumoor; John, Kuruvilla; Farooqui, Zuber

The recent Intergovernmental Panel on Climate Change report predicts significant temperature increases over the century which constitutes the pulse of climate variability in a region. A modeling study was performed to identify the potential impact of temperature perturbations on tropospheric ozone concentrations in South Texas. A future case modeling scenario which incorporates appropriate emission reduction strategies without accounting for climatic inconsistencies was used in this study. The photochemical modeling was undertaken for a high ozone episode of 13-20 September 1999, and a future modeling scenario was projected for ozone episode days in 2007 utilizing the meteorological conditions prevalent in the base year. The temperatures were increased uniformly throughout the simulation domain and through the vertical layers by 2°C, 3°C, 4°C, 5°C, and 6°C, respectively in the future year modeling case. These temperature perturbations represented the outcome of extreme climate change within the study region. Significantly large changes in peak ozone concentrations were predicted by the photochemical model. For the 6°C temperature perturbation, the greatest amplification in the maximum 8-h ozone concentrations within urban areas of the modeling domain was approximately 12 ppb. In addition, transboundary flux from major industrialized urban areas played a major role in supplementing the high ozone concentrations during the perturbed temperature scenarios. The Unites States Environmental Protection Agency (USEPA) is currently proposing stricter 8-h ozone standards. The effect of temperature perturbations on ozone exceedances based on current and potential stringent future National Ambient Air Quality Standards (NAAQS) was also studied. Temperatures had an appreciable spatial impact on the 8-h ozone exceedances with a considerable increase in spatial area exceeding the NAAQS for the 8-h ozone levels within the study region for each successive augmentation in temperature. The number of exceedances of the 8-h ozone standard increased significantly with each degree rise of temperature with the problem becoming even more acute in light of stricter future proposed standards of ozone.

Growth and characterization of crystals for room temperature I.R. detectors and second harmonic generation devices

NASA Technical Reports Server (NTRS)

Lal, R. B.

1995-01-01

One of the major objectives of this program was to modify the triglycine sulfate (TGS) crystals with suitable dopants and variants to achieve better pyroelectric properties and improved infrared detectivities (D(sup *)), and higher Curie transition temperature compared to undoped TGS crystals. Towards these objectives, many promising dopants, both inorganic and organic, were investigated in the last few years. These dopants gave significant improvement in the D(sup *) value of the infrared detectors fabricated from the grown crystals with no significant increase in the Curie temperature (49 C). The IR detectors were fabricated at EDO/Barnes Engineering Division, Shelton, CT. In the last one year many TGS crystals doped with urea were grown using the low temperature solution crystal growth facility. It is found that doping with urea, the normalized growth yield increased significantly compared to pure TGS crystals and there is an improvement in the pyroelectric and dielectric constant values of doped crystals. This gave a significant increase in the materials figure of merits. The Vicker's hardness of 10 wt percent urea doped crystals is found to be about three times higher in the (010) direction compared to undoped crystals. This report describes in detail the results of urea doped TGS crystals.

Developmental Effects of Ocean Acidification Conditions and Elevated Temperature on Homarus Americanus Larvae

NASA Astrophysics Data System (ADS)

Mcveigh, H.; Waller, J. D.

2016-02-01

The Gulf of Maine is experiencing a rapid warming in sea surface temperature and a marked decrease in pH. This study aimed to quantify the impact of elevated temperature and acidification on the larval development of the iconic American lobster (Homarus americanus). Experimental conditions were reflective of current and IPCC predicted levels of temperature and pCO2 to be reached by the end of the century. Larvae were measured for growth (carapace length), development time, and survivorship over the larval duration. Treatments of elevated temperatures experienced decreased development time across the larval stages of H. americanus. Consequently mortality increased at a significantly higher rate under elevated temperature. An increase in larval mortality may decrease recruitment to the commercial fishery, thus impacting the most valuable single species in the state of Maine. Furthermore, experimental pCO2 treatments yielded a significantly decreased development time between larval stages II and III, yet did not have a significant impact on carapace length or mortality. This study indicates that warmer temperatures may have a greater influence than decreased pH on larval development and survival. Determining how this species may respond to changing climactic conditions will better inform the sustainability efforts of such a critical marine fishery.

Relationship between extreme Precipitation and Temperature over Japan: An analysis from Multi-GCMs and Multi-RCMs products

NASA Astrophysics Data System (ADS)

Nayak, S.; Dairaku, K.; Takayabu, I.

2014-12-01

According to the IPCC reports, the concentration of CO­2 has been increasing and projected to be increased significantly in future (IPCC, 2012). This can have significant impacts on climate. For instance, Dairaku and Emori (2006) examined over south Asia by doubling CO2 and documented an increase in precipitation intensities during Indian summer monsoon. This would increase natural disasters such as floods, landslide, coastal disaster, erosion etc. Recent studies investigated whether the rate of increase of extreme precipitation is related with the rate expected by Clausius-Clapeyron (CC) relationship (approximately 7% per degree temperature rise). In our study, we examine whether this rate can increase or decrease in the future regional climate scenarios over Japan. We have analysed the ensemble experiments by three RCMs(NHRCM, NRAMS, WRF) forced by JRA25 as well as three GCMs (CCSM4, MIROC5, MRI-GCM3) for the current climate (1981-2000) and future scenario (2081-2100, RCP4.5) over Japan. We have stratified the extreme (99th, 95th, 90th, 75th percentile) precipitation of daily sum and daily maximum of hourly precipitation intensities of wet events based on daily mean temperature in bins of 1°C width for annual as well as for each season (DJF, MAM, JJA, SON). The results indicate that precipitation intensity increases when temperature increases roughly up to 22 °C and further increase of temperature decreases the precipitation intensities. The obtained results are consistent and match with the observation (APHRODITE dataset) over Japan. The decrease of precipitation at higher temperature mainly can be found in JJA. It is also noticed that the rate of specific humidity is estimated higher during JJA than other seasons. The rate of increase of extreme precipitation is similar to the rate expected by CC relation except DJF (nearly twice of CC relation) in current climate. This rate becomes to be significantly larger in future scenario for higher temperatures than in current climate.Acknowledgement: This study is conducted as part of a research at NIED, Japan (PI: Koji Dairaku) of Research Program on Climate Change Adaptation (RECCA) and was supported by the SOUSEI Program, funded by Ministry of Education, Culture, Sports, Science and Technology, Government of Japan.

Novel levan and pNIPA temperature sensitive hydrogels for 5-ASA controlled release.

PubMed

Osman, Asila; Oner, Ebru Toksoy; Eroglu, Mehmet S

2017-06-01

Levan based cross-linker was successfully synthesized and used to prepare a series of more biocompatible and temperature responsive levan/N-isopropyl acrylamide (levan/pNIPA) hydrogels by redox polymerization at room temperature. Volume phase transition temperature (VPTT) of the hydrogels were precisely determined by derivative differential scanning calorimetry (DDSC). Incorporation of levan into the pNIPA hydrogel increased the VPTT from 32.8°C to 35.09°C, approaching to body temperature. Swelling behavior and 5-aminosalicylic acid (5-ASA) release of the hydrogels were found to vary significantly with temperature and composition. Moreover, a remarkable increase in thermal stability of levan within hydrogel with increase of pNIPA content was recorded. The biocompatibility of the hydrogels were tested against mouse fibroblast L929 cell line in phosphate buffer saline (PBS, pH 7.4). The hydrogels showed increasing biocompatibility with increasing levan ratio, indicating levan enhanced the hydrogel surface during swelling. Copyright © 2017 Elsevier Ltd. All rights reserved.

Response of water temperatures and stratification to changing climate in three lakes with different morphometry

NASA Astrophysics Data System (ADS)

Magee, Madeline R.; Wu, Chin H.

2017-12-01

Water temperatures and stratification are important drivers for ecological and water quality processes within lake systems, and changes in these with increases in air temperature and changes to wind speeds may have significant ecological consequences. To properly manage these systems under changing climate, it is important to understand the effects of increasing air temperatures and wind speed changes in lakes of different depths and surface areas. In this study, we simulate three lakes that vary in depth and surface area to elucidate the effects of the observed increasing air temperatures and decreasing wind speeds on lake thermal variables (water temperature, stratification dates, strength of stratification, and surface heat fluxes) over a century (1911-2014). For all three lakes, simulations showed that epilimnetic temperatures increased, hypolimnetic temperatures decreased, the length of the stratified season increased due to earlier stratification onset and later fall overturn, stability increased, and longwave and sensible heat fluxes at the surface increased. Overall, lake depth influences the presence of stratification, Schmidt stability, and differences in surface heat flux, while lake surface area influences differences in hypolimnion temperature, hypolimnetic heating, variability of Schmidt stability, and stratification onset and fall overturn dates. Larger surface area lakes have greater wind mixing due to increased surface momentum. Climate perturbations indicate that our larger study lakes have more variability in temperature and stratification variables than the smaller lakes, and this variability increases with larger wind speeds. For all study lakes, Pearson correlations and climate perturbation scenarios indicate that wind speed has a large effect on temperature and stratification variables, sometimes greater than changes in air temperature, and wind can act to either amplify or mitigate the effect of warmer air temperatures on lake thermal structure depending on the direction of local wind speed changes.

The cost of muscle power production: muscle oxygen consumption per unit work increases at low temperatures in Xenopus laevis.

PubMed

Seebacher, Frank; Tallis, Jason A; James, Rob S

2014-06-01

Metabolic energy (ATP) supply to muscle is essential to support activity and behaviour. It is expected, therefore, that there is strong selection to maximise muscle power output for a given rate of ATP use. However, the viscosity and stiffness of muscle increases with a decrease in temperature, which means that more ATP may be required to achieve a given work output. Here, we tested the hypothesis that ATP use increases at lower temperatures for a given power output in Xenopus laevis. To account for temperature variation at different time scales, we considered the interaction between acclimation for 4 weeks (to 15 or 25°C) and acute exposure to these temperatures. Cold-acclimated frogs had greater sprint speed at 15°C than warm-acclimated animals. However, acclimation temperature did not affect isolated gastrocnemius muscle biomechanics. Isolated muscle produced greater tetanus force, and faster isometric force generation and relaxation, and generated more work loop power at 25°C than at 15°C acute test temperature. Oxygen consumption of isolated muscle at rest did not change with test temperature, but oxygen consumption while muscle was performing work was significantly higher at 15°C than at 25°C, regardless of acclimation conditions. Muscle therefore consumed significantly more oxygen at 15°C for a given work output than at 25°C, and plastic responses did not modify this thermodynamic effect. The metabolic cost of muscle performance and activity therefore increased with a decrease in temperature. To maintain activity across a range of temperature, animals must increase ATP production or face an allocation trade-off at lower temperatures. Our data demonstrate the potential energetic benefits of warming up muscle before activity, which is seen in diverse groups of animals such as bees, which warm flight muscle before take-off, and humans performing warm ups before exercise. © 2014. Published by The Company of Biologists Ltd.

Contrasting effects of warming and increased snowfall on Arctic tundra plant phenology over the past two decades.

PubMed

Bjorkman, Anne D; Elmendorf, Sarah C; Beamish, Alison L; Vellend, Mark; Henry, Gregory H R

2015-12-01

Recent changes in climate have led to significant shifts in phenology, with many studies demonstrating advanced phenology in response to warming temperatures. The rate of temperature change is especially high in the Arctic, but this is also where we have relatively little data on phenological changes and the processes driving these changes. In order to understand how Arctic plant species are likely to respond to future changes in climate, we monitored flowering phenology in response to both experimental and ambient warming for four widespread species in two habitat types over 21 years. We additionally used long-term environmental records to disentangle the effects of temperature increase and changes in snowmelt date on phenological patterns. While flowering occurred earlier in response to experimental warming, plants in unmanipulated plots showed no change or a delay in flowering over the 21-year period, despite more than 1 °C of ambient warming during that time. This counterintuitive result was likely due to significantly delayed snowmelt over the study period (0.05-0.2 days/yr) due to increased winter snowfall. The timing of snowmelt was a strong driver of flowering phenology for all species - especially for early-flowering species - while spring temperature was significantly related to flowering time only for later-flowering species. Despite significantly delayed flowering phenology, the timing of seed maturation showed no significant change over time, suggesting that warmer temperatures may promote more rapid seed development. The results of this study highlight the importance of understanding the specific environmental cues that drive species' phenological responses as well as the complex interactions between temperature and precipitation when forecasting phenology over the coming decades. As demonstrated here, the effects of altered snowmelt patterns can counter the effects of warmer temperatures, even to the point of generating phenological responses opposite to those predicted by warming alone. © 2015 John Wiley & Sons Ltd.

Rising air and stream-water temperatures in Chesapeake Bay region, USA

USGS Publications Warehouse

Rice, Karen C.; Jastram, John D.

2015-01-01

Monthly mean air temperature (AT) at 85 sites and instantaneous stream-water temperature (WT) at 129 sites for 1960–2010 are examined for the mid-Atlantic region, USA. Temperature anomalies for two periods, 1961–1985 and 1985–2010, relative to the climate normal period of 1971–2000, indicate that the latter period was statistically significantly warmer than the former for both mean AT and WT. Statistically significant temporal trends across the region of 0.023 °C per year for AT and 0.028 °C per year for WT are detected using simple linear regression. Sensitivity analyses show that the irregularly sampled WT data are appropriate for trend analyses, resulting in conservative estimates of trend magnitude. Relations between 190 landscape factors and significant trends in AT-WT relations are examined using principal components analysis. Measures of major dams and deciduous forest are correlated with WT increasing slower than AT, whereas agriculture in the absence of major dams is correlated with WT increasing faster than AT. Increasing WT trends are detected despite increasing trends in streamflow in the northern part of the study area. Continued warming of contributing streams to Chesapeake Bay likely will result in shifts in distributions of aquatic biota and contribute to worsened eutrophic conditions in the bay and its estuaries.

Chapter 3: Climate Change

Treesearch

Steve McNulty; Jennifer Moore Myers; Peter Caldwell; Ge Sun

2011-01-01

Since 1960, all but two southern capital cities (Montgomery, AL and Oklahoma City, OK) have experienced a statistically significant increase in average annual temperature (approximately 0.016 °C), but none has experienced significant trends in precipitation. The South is forecasted to experience warmer temperatures for the duration of the 21st century; forecasts are...

Brief anesthesia, but not voluntary locomotion, significantly alters cortical temperature

PubMed Central

Shirey, Michael J.; Kudlik, D'Anne E.; Huo, Bing-Xing; Greene, Stephanie E.; Drew, Patrick J.

2015-01-01

Changes in brain temperature can alter electrical properties of neurons and cause changes in behavior. However, it is not well understood how behaviors, like locomotion, or experimental manipulations, like anesthesia, alter brain temperature. We implanted thermocouples in sensorimotor cortex of mice to understand how cortical temperature was affected by locomotion, as well as by brief and prolonged anesthesia. Voluntary locomotion induced small (∼0.1°C) but reliable increases in cortical temperature that could be described using a linear convolution model. In contrast, brief (90-s) exposure to isoflurane anesthesia depressed cortical temperature by ∼2°C, which lasted for up to 30 min after the cessation of anesthesia. Cortical temperature decreases were not accompanied by a concomitant decrease in the γ-band local field potential power, multiunit firing rate, or locomotion behavior, which all returned to baseline within a few minutes after the cessation of anesthesia. In anesthetized animals where core body temperature was kept constant, cortical temperature was still >1°C lower than in the awake animal. Thermocouples implanted in the subcortex showed similar temperature changes under anesthesia, suggesting these responses occur throughout the brain. Two-photon microscopy of individual blood vessel dynamics following brief isoflurane exposure revealed a large increase in vessel diameter that ceased before the brain temperature significantly decreased, indicating cerebral heat loss was not due to increased cerebral blood vessel dilation. These data should be considered in experimental designs recording in anesthetized preparations, computational models relating temperature and neural activity, and awake-behaving methods that require brief anesthesia before experimental procedures. PMID:25972579

Effects of a warm hand bath on the blood flow in the shoulder, skin and deep body temperature, autonomic nervous activity, and subjective comfort in healthy women: An experimental cross-over trial.

PubMed

Kudo, Yukiko; Sasaki, Makiko; Kikuchi, Yukiko; Sugiyama, Reiko; Hasebe, Makiko; Ishii, Noriko

2018-06-19

The present study was conducted in order to clarify the effects of a warm hand bath at 40°C for 10 min on the blood flow in the shoulder, skin and deep body temperature, autonomic nervous activity, and subjective comfort in healthy women. The study's participants were 40 healthy adult women who were randomly assigned to either a structured hand bath first and no hand bath second (Group A) or to no hand bath first and a hand bath second (Group B). The blood flow in the shoulder, skin and deep body temperature, autonomic nervous activity, and subjective comfort then were recorded in all the participants. A repeated-measures ANOVA revealed no significant difference in the blood flow in the right shoulder or deep body temperature between groups. The skin temperature of the hands, forearms, and arms was significantly increased, but not of the face and upper back. The skin temperature of the forearms was maintained at 0.5°C-1°C higher for 30 min in the hand bath group, compared with the no hand bath group. The hand bath group had a significantly higher heart rate while bathing and a significantly lower parasympathetic nerve activity level during bathing. No significant difference was seen in the sympathetic activity level between groups. The hand bath group had a significantly higher subjective comfort level. Hand baths can improve the level of subjective comfort and increase the heart rate and might affect autonomic nervous activity. The skin temperature of the forearms was maintained for 30 min in the hand bath group. © 2018 Japan Academy of Nursing Science.

Problems in evaluating regional and local trends in temperature: An example from eastern Colorado, USA

USGS Publications Warehouse

Pielke, R.A.; Stohlgren, T.; Schell, L.; Parton, W.; Doesken, N.; Redmond, K.; Moeny, J.; McKee, T.; Kittel, T.G.F.

2002-01-01

We evaluated long-term trends in average maximum and minimum temperatures, threshold temperatures, and growing season in eastern Colorado, USA, to explore the potential shortcomings of many climate-change studies that either: (1) generalize regional patterns from single stations, single seasons, or a few parameters over short duration from averaging dissimilar stations: or (2) generalize an average regional pattern from coarse-scale general circulation models. Based on 11 weather stations, some trends were weakly regionally consistent with previous studies of night-time temperature warming. Long-term (80 + years) mean minimum temperatures increased significantly (P < 0.2) in about half the stations in winter, spring, and autumn and six stations had significant decreases in the number of days per year with temperatures ??? - 17.8 ??C (???0??F). However, spatial and temporal variation in the direction of change was enormous for all the other weather parameters tested, and, in the majority of tests, few stations showed significant trends (even at P < 0.2). In summer, four stations had significant increases and three stations had significant decreases in minimum temperatures, producing a strongly mixed regional signal. Trends in maximum temperature varied seasonally and geographically, as did trends in threshold temperature days ???32.2??C (???90??F) or days ???37.8??C (???100??F). There was evidence of a subregional cooling in autumn's maximum temperatures, with five stations showing significant decreasing trends. There were many geographic anomalies where neighbouring weather stations differed greatly in the magnitude of change or where they had significant and opposite trends. We conclude that sub-regional spatial and seasonal variation cannot be ignored when evaluating the direction and magnitude of climate change. It is unlikely that one or a few weather stations are representative of regional climate trends, and equally unlikely that regionally projected climate change from coarse-scale general circulation models will accurately portray trends at sub-regional scales. However, the assessment of a group of stations for consistent more qualitative trends (such as the number of days less than - 17.8??C, such as we found) provides a reasonably robust procedure to evaluate climate trends and variability. Copyright ?? 2002 Royal Meteorological Society.

Lessons Learned from the Wide Field Camera 3 Flight Correlation

NASA Technical Reports Server (NTRS)

Peabody, Hume L.; Stavely, Richard A.; Townsend, Jackie; Abel, Josh; Mandi, Joe; Bast, William

2010-01-01

The Wide Field Camera 3 (WFC3) instrument was installed into the Hubble Space Telescope (HST) as part of the activities for STS (Space Transportation System)-125 (HST Servicing Mission 4). Initial model predictions for power and radiator temperature were not in good agreement with flight data during a relatively hot, stable period, with the flight power and temperatures being significantly higher than predictions. Significant efforts were undertaken to identify the causes of the discrepancies and to resolve the flight model correlation problems as the thermal vacuum test correlation indicated good agreement. The WFC3 thermal design performance has proven difficult to accurately predict, since the power dissipation on the radiator typically increases as the radiator temperature increases, due to a Thermo Electric Cooler (TEC) attached to the this radiator. This self beating continues until the radiative emissive capability is met for a given temperature, and only then does the system find a quasi-steady regime. Various other factors may also contribute to the radiator temperature, such as backloadlng from the observatory itself and the planet, local high-absorptivity regions near fasteners/holes, and temperature varying parasitic heat leaks from the instrument itself to the radiator. Each of these effects in turn may increase the radiator temperature, and furthermore the demand on the TEC.

Increased seawater temperature increases the abundance and alters the structure of natural Vibrio populations associated with the coral Pocillopora damicornis

PubMed Central

Tout, Jessica; Siboni, Nachshon; Messer, Lauren F.; Garren, Melissa; Stocker, Roman; Webster, Nicole S.; Ralph, Peter J.; Seymour, Justin R.

2015-01-01

Rising seawater temperature associated with global climate change is a significant threat to coral health and is linked to increasing coral disease and pathogen-related bleaching events. We performed heat stress experiments with the coral Pocillopora damicornis, where temperature was increased to 31°C, consistent with the 2–3°C predicted increase in summer sea surface maxima. 16S rRNA amplicon sequencing revealed a large shift in the composition of the bacterial community at 31°C, with a notable increase in Vibrio, including known coral pathogens. To investigate the dynamics of the naturally occurring Vibrio community, we performed quantitative PCR targeting (i) the whole Vibrio community and (ii) the coral pathogen Vibrio coralliilyticus. At 31°C, Vibrio abundance increased by 2–3 orders of magnitude and V. coralliilyticus abundance increased by four orders of magnitude. Using a Vibrio-specific amplicon sequencing assay, we further demonstrated that the community composition shifted dramatically as a consequence of heat stress, with significant increases in the relative abundance of known coral pathogens. Our findings provide quantitative evidence that the abundance of potential coral pathogens increases within natural communities of coral-associated microbes as a consequence of rising seawater temperature and highlight the potential negative impacts of anthropogenic climate change on coral reef ecosystems. PMID:26042096

Cellular respiration, oxygen consumption, and trade-offs of the jellyfish Cassiopea sp. in response to temperature change

NASA Astrophysics Data System (ADS)

Aljbour, Samir M.; Zimmer, Martin; Kunzmann, Andreas

2017-10-01

Pelagic jellyfish blooms are increasing worldwide as a potential response to climate-change. However, virtually nothing is known about physiological responses of jellyfish to e.g. sudden changes in water temperature due to extreme weather events. When confronted with a sudden decrease or increase in water temperature by 6 °C, medusae of Cassiopea sp. exhibited a strong response in locomotor activity (i.e., bell pulsation increased and decreased by ca. 37 and 46% in hot and cold acute (2 h) treatments, respectively) relative to control. Although medusae significantly gained in body mass (wet weight) upon chronic (2 weeks) heat treatment, their body size (e.g., bell diameter) did not change over this time interval. In contrast, chronic cold treatment resulted in both significant shrinking (reduced diameter) and mass loss. Measurements of mitochondrial electron transport system (ETS) activities and rate of respiratory oxygen uptake (MO2) are good estimates of energy consumption and the potential aerobic metabolic rates of an organism. While both acute treatments significantly increased ETS-activities, acclimation over two weeks resulted in a drop in activities to the control levels. Whereas acute heat treatment significantly increased MO2, chronic exposure resulted in significant MO2 decrease compared to control; however no changes in MO2 could be observed in both acute and chronic cold treatments. Overall these results suggest an enhanced growth in response to global warming, whereas low temperatures may set the limits for successful invasion of Cassiopea into colder water bodies. Our results provide a framework for understanding the physiological tolerance of Cassiopea under possible future climate changes.

Are low altitude alpine tundra ecosystems under threat? A case study from the Parc National de la Gaspésie, Québec

NASA Astrophysics Data System (ADS)

Dumais, Catherine; Ropars, Pascale; Denis, Marie-Pier; Dufour-Tremblay, Geneviève; Boudreau, Stéphane

2014-09-01

According to the 2007 IPCC report, the alpine tundra ecosystems found on low mountains of the northern hemisphere are amongst the most threatened by climate change. A treeline advance or a significant erect shrub expansion could result in increased competition for the arctic-alpine species usually found on mountaintops and eventually lead to their local extinction. The objectives of our study were to identify recent changes in the cover and growth of erect woody vegetation in the alpine tundra of Mont de la Passe, in the Parc National de la Gaspésie (Québec, Canada). The comparison of two orthorectified aerial photos revealed no significant shift of the treeline between 1975 and 2004. During the same period however, shrub species cover increased from 20.2% to 30.4% in the lower alpine zone. Dendrochronological analyses conducted on Betula glandulosa Michx. sampled at three different positions along an altitudinal gradient (low, intermediate and high alpine zone) revealed that the climatic determinants of B. glandulosa radial growth become more complex with increasing altitude. In the lower alpine zone, B. glandulosa radial growth is only significantly associated positively to July temperature. In the intermediate alpine zone, radial growth is associated positively to July temperature but negatively to March temperature. In the high alpine zone, radial growth is positively associated to January, July and August temperature but negatively to March temperature. The positive association between summer temperatures and radial growth suggests that B. glandulosa could potentially benefit from warmer temperatures, a phenomenon that could lead to an increase in its cover over the next few decades. Although alpine tundra vegetation is not threatened in the short-term in the Parc National de la Gaspésie, erect shrub cover, especially B. glandulosa, could likely increase in the near future, threatening the local arctic-alpine flora.

Circulatory failure during severe hyperthermia in dog.

PubMed

Miki, K; Morimoto, T; Nose, H; Itoh, T; Yamada, S

1983-01-01

The effect of acute hyperthermia on circulatory function was studied in 6 mongrel dogs. At a core temperature of about 40 degrees C, central venous pressure and stroke volume were maintained at almost normal level. Cardiac output significantly increased (26 ml/(kg . min)) while systemic vascular resistance significantly decreased (1.2 mmHg . sec/ml). In addition, significant decrease in vascular compliance by 40% was observed. When body temperature was raised further (severe hyperthermia), an abrupt fall of arterial pressure was observed at the rectal temperature of about 41-42 degrees C. Concomitant decreases in central venous pressure (3 mmHg), stroke volume (2.1 ml/beat) and cardiac output (29 ml/(kg . min)) were observed while heart rate increased (48 beats/min). These results suggest that the decrease in cardiac output during severe hyperthermia is due to the fall of central venous pressure, and the fall was attributed to the increase in unstressed vascular volume of systemic circulation due to the heat-induced cutaneous vasodilation. The observed decrease in systemic vascular compliance is considered to have a significant role in the maintenance of central venous pressure under hyperthermia.

[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.

Trends in Middle East climate extreme indices from 1950 to 2003

NASA Astrophysics Data System (ADS)

Zhang, Xuebin; Aguilar, Enric; Sensoy, Serhat; Melkonyan, Hamlet; Tagiyeva, Umayra; Ahmed, Nader; Kutaladze, Nato; Rahimzadeh, Fatemeh; Taghipour, Afsaneh; Hantosh, T. H.; Albert, Pinhas; Semawi, Mohammed; Karam Ali, Mohammad; Said Al-Shabibi, Mansoor Halal; Al-Oulan, Zaid; Zatari, Taha; Al Dean Khelet, Imad; Hamoud, Saleh; Sagir, Ramazan; Demircan, Mesut; Eken, Mehmet; Adiguzel, Mustafa; Alexander, Lisa; Peterson, Thomas C.; Wallis, Trevor

2005-11-01

A climate change workshop for the Middle East brought together scientists and data for the region to produce the first area-wide analysis of climate extremes for the region. This paper reports trends in extreme precipitation and temperature indices that were computed during the workshop and additional indices data that became available after the workshop. Trends in these indices were examined for 1950-2003 at 52 stations covering 15 countries, including Armenia, Azerbaijan, Bahrain, Cyprus, Georgia, Iran, Iraq, Israel, Jordan, Kuwait, Oman, Qatar, Saudi Arabia, Syria, and Turkey. Results indicate that there have been statistically significant, spatially coherent trends in temperature indices that are related to temperature increases in the region. Significant, increasing trends have been found in the annual maximum of daily maximum and minimum temperature, the annual minimum of daily maximum and minimum temperature, the number of summer nights, and the number of days where daily temperature has exceeded its 90th percentile. Significant negative trends have been found in the number of days when daily temperature is below its 10th percentile and daily temperature range. Trends in precipitation indices, including the number of days with precipitation, the average precipitation intensity, and maximum daily precipitation events, are weak in general and do not show spatial coherence. The workshop attendees have generously made the indices data available for the international research community.

Effects of temperature, strain rate, and vacancies on tensile and fatigue behaviors of silicon-based nanotubes

NASA Astrophysics Data System (ADS)

Jeng, Yeau-Ren; Tsai, Ping-Chi; Fang, Te-Hua

2005-02-01

This paper adopts the Tersoff-Brenner many-body potential function to perform molecular dynamics simulations of the tensile and fatigue behaviors of hypothetical silicon-based tubular nanostructures at various temperatures, strain rates, and vacancy percentages. The tensile test results indicate that with a predicted Young’s modulus of approximately 60GPa , silicon nanotubes (SiNTs) are significantly less stiff than conventional carbon nanotubes. It is observed that the presence of hydrogen has a significant influence on the tensile strength of SiNTs . Additionally, the present results indicate that the tensile strength clearly decreases with increasing temperature and with decreasing strain rate. Moreover, it is shown that the majority of the mechanical properties considered in the present study decrease with an increasing vacancy percentage. Regarding the fatigue tests, this study uses a standard theoretical model to derive curves of amplitude stress versus number of cycles for the current nanotubes. The results demonstrate that the fatigue limit of SiNTs increases with a decreasing vacancy percentage and with increasing temperature.

Heat increases MDMA-enhanced NAcc 5-HT and body temperature, but not MDMA self-administration.

PubMed

Feduccia, Allison A; Kongovi, Nundhun; Duvauchelle, Christine L

2010-12-01

There is a concern that hot environments enhance adverse effects of 3,4-methylenedioxymethamphetamine (MDMA or "Ecstasy"). In this study, long-term (4-weeks) daily MDMA self-administration sessions and an MDMA Challenge test were conducted with rats under normal and high thermal conditions (23° or 32°C). During MDMA self-administration sessions, activity and body temperature were increased by heat or MDMA experience, while MDMA self-administration rates increased with experience, but were comparable between thermal conditions. At the MDMA Challenge test (3.0 mg/kg, i.v.), in vivo microdialysis showed that nucleus accumbens serotonin (NAcc 5-HT) and dopamine (DA) responses were significantly increased in both thermal conditions. In the heated environment, MDMA-stimulated 5-HT responses and core temperature (but not DA) were significantly greater than at room temperature. Though the heated environment did not acutely boost MDMA intake, exaggerated NAcc 5-HT responses to MDMA may result in 5-HT depletion; a condition associated with Ecstasy use escalation and neural dysfunctions altering mood and cognition. Copyright © 2010 Elsevier B.V. All rights reserved.

Heat increases MDMA-enhanced NAcc 5-HT and body temperature, but not MDMA self-administration

PubMed Central

Feduccia, Allison A.; Kongovi, Nundhun

2011-01-01

There is concern that hot environments enhance adverse effects of 3,4-methylenedioxymethamphetamine (MDMA or “Ecstasy”). In this study, long-term (4-wks) daily MDMA self-administration sessions and an MDMA challenge test were conducted with rats under normal and high thermal conditions (23° or 32° C). During MDMA self-administration sessions, activity and body temperature were increased by heat or MDMA experience, while MDMA self-administration rates increased with experience, but were comparable between thermal conditions. At the MDMA challenge test (3.0 mg/kg, i.v.), in vivo microdialysis showed nucleus accumbens serotonin (NAcc 5-HT) and dopamine (DA) responses were significantly increased in both thermal conditions. In the heated environment, MDMA-stimulated 5-HT responses and core temperature (but not DA) were significantly greater than at room temperature. Though the heated environment did not acutely boost MDMA intake, exaggerated NAcc 5-HT responses to MDMA may result in 5-HT depletion; a condition associated with Ecstasy use escalation and neural dysfunctions altering mood and cognition. PMID:20888192

Caldera unrest detected with seawater temperature anomalies at Deception Island, Antarctic Peninsula

NASA Astrophysics Data System (ADS)

Berrocoso, M.; Prates, G.; Fernández-Ros, A.; Peci, L. M.; de Gil, A.; Rosado, B.; Páez, R.; Jigena, B.

2018-04-01

Increased thermal activity was detected to coincide with the onset of volcano inflation in the seawater-filled caldera at Deception Island. This thermal activity was manifested in pulses of high water temperature that coincided with ocean tide cycles. The seawater temperature anomalies were detected by a thermometric sensor attached to the tide gauge (bottom pressure sensor). This was installed where the seawater circulation and the locations of known thermal anomalies, fumaroles and thermal springs, together favor the detection of water warmed within the caldera. Detection of the increased thermal activity was also possible because sea ice, which covers the entire caldera during the austral winter months, insulates the water and thus reduces temperature exchange between seawater and atmosphere. In these conditions, the water temperature data has been shown to provide significant information about Deception volcano activity. The detected seawater temperature increase, also observed in soil temperature readings, suggests rapid and near-simultaneous increase in geothermal activity with onset of caldera inflation and an increased number of seismic events observed in the following austral summer.

Effects of an advanced temperature cycle on smolt development and endocrinology indicate that temperature is not a zeitgeber for smolting in Atlantic salmon

USGS Publications Warehouse

McCormick, S.D.; Shrimpton, J.M.; Moriyama, S.; Bjornsson, Bjorn Thrandur

2002-01-01

Atlantic salmon (Salmo salar) juveniles were reared under simulated conditions of normal photoperiod (LDN) or short days (LD 9:15) and ambient temperature (AMB: normal temperature increases in April) or an advanced temperature cycle (ADV: temperature increases in February). Under both photoperiod conditions, the timing of increased and peak levels of gill Na+,K+-ATPase activity were not altered by temperature, although the rate of increase was initially greater under ADV. ADV/LD 9:15 resulted in peak gill Na+,K+-ATPase activity that was half of that seen under normal photoperiod and temperature conditions. Plasma growth hormone (GH) levels increased threefold in late March under ADV/LDN, but not under ADV/LD 9:15, indicating that there is a photoperiod-dependent effect of temperature on levels of this hormone. Plasma insulin-like growth factor I (IGF-I) increased in spring in all groups, with increases occurring significantly earlier in the ADV/LDN group. In each photoperiod condition, the advanced temperature cycle resulted in large decreases in plasma thyroxine (T4) levels in March, which subsequently recovered, whereas plasma 3,5,3???-triiodo-L-thyronine (T3) levels were not substantially affected by either photoperiod or temperature. There was no consistent pattern of change in plasma cortisol levels. The results do not provide support for the role of temperature as a zeitgeber, but do indicate that temperature has a role in the timing of smolting by affecting the rate of development and interacting with the photoperiod.

Effects of postharvest handling conditions on internalization and growth of Salmonella enterica in tomatoes.

PubMed

Zhou, Bin; Luo, Yaguang; Nou, Xiangwu; Yang, Yang; Wu, Yunpeng; Wang, Qin

2014-03-01

Salmonella internalization in tomatoes during postharvest handling is a major food safety concern. This study was conducted to determine the effect of immersion time, immersion depth, and temperature differential between bacterial suspension and tomato pulp on the internalization of Salmonella enterica in tomato fruits. The effect of storage temperature and duration on the survival and growth of internalized Salmonella cells was also evaluated. Overall, immersion time significantly affected the incidence and extent of S. enterica internalization (P < 0.0001), with a linear correlation between immersion time and Salmonella internalization. The depth of Salmonella internalization in tomato tissues also increased with increasing immersion time. Immersion time also significantly influenced the degree to which the temperature differential affected Salmonella internalization. With an immersion time of 2 min, the temperature differential had no significant effect on Salmonella internalization (P = 0.2536). However, with an immersion time of 15 min, a significantly larger Salmonella population became internalized in tomatoes immersed in solutions with a -30°F (-16.7°C) temperature differential. Internalized S. enterica cells persisted in the core tissues during 14 days of storage. Strain type and storage duration significantly affected (P < 0.05) both the frequency detected and the population of internalized Salmonella recovered, but storage temperatures of 55 to 70°F (12.8 to 21.1°C) did not (P > 0.05). These findings indicate the importance of preventing pathogen internalization during postharvest handling.

Hot or not? Thermal reactions to social contact.

PubMed

Hahn, Amanda C; Whitehead, Ross D; Albrecht, Marion; Lefevre, Carmen E; Perrett, David I

2012-10-23

Previous studies using thermal imaging have suggested that face and body temperature increase during periods of sexual arousal. Additionally, facial skin temperature changes are associated with other forms of emotional arousal, including fear and stress. This study investigated whether interpersonal social contact can elicit facial temperature changes. Study 1: infrared images were taken during a standardized interaction with a same- and opposite-sex experimenter using skin contact in a number of potentially high-intimate (face and chest) and low-intimate (arm and palm) locations. Facial skin temperatures significantly increased from baseline during the face and chest contact, and these temperature shifts were larger when contact was made by an opposite-sex experimenter. Study 2: the topography of facial temperature change was investigated in five regions: forehead, periorbital, nose, mouth and cheeks. Increased temperature in the periorbital, nose and mouth regions predicted overall facial temperature shifts to social contact. Our findings demonstrate skin temperature changes are a sensitive index of arousal during interpersonal interactions.

Effects of ingested crude and dispersed crude oil on thermoregulation in ducks (Anas platyrhynchos)

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

Jenssen, B.M.

1989-02-01

Thermoregulatory effects of ingested doses of Statfjord A crude oil and of this oil mixed with the dispersant Finasol OSR-5 were studied in adult domestic ducks (Anas platyrhynchos) exposed to ambient temperatures of +16 degrees C and -17 degrees C. The data show that ingestion of both the crude and the oil-dispersant mixture resulted in an increased body temperature during exposure to the low ambient temperature (-17 degrees C). Neither contaminant had any effect on body temperature during exposure to +16 degrees C. Ingestion of the contaminants had no effect on metabolic heat production at either ambient temperature. The breastmore » skin temperature of the ducks in both contaminated groups was significantly decreased when the ducks were exposed to the low ambient temperature. This indicates that the increase in body temperature observed in the contaminated ducks at the low ambient temperature is due to an increase in peripheral vasoconstriction.« less

[Indoor simulation on dew formation on plant leaves].

PubMed

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

2014-03-01

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

Incubation temperature modifies neonatal thermoregulation in the lizard Anolis carolinensis.

PubMed

Goodman, Rachel M; Walguarnery, Justin W

2007-08-01

The thermal environment experienced during embryonic development can profoundly affect the phenotype, and potentially the fitness, of ectothermic animals. We examined the effect of incubation temperature on the thermal preferences of juveniles in the oviparous lizard, Anolis carolinensis. Temperature preference trials were conducted in a laboratory thermal gradient within 48 hr of hatching and after 22-27 days of maintenance in a common laboratory environment. Incubation temperature had a significant effect on the upper limit of the interquartile range (IQR) of temperatures selected by A. carolinensis within the first 2 days after hatching. Between the first and second trials, the IQR of selected temperatures decreased significantly and both the lower limit of the IQR and the median selected temperature increased significantly. This, along with a significant incubation temperature by time interaction in the upper limit of the IQR, resulted in a pattern of convergence in thermoregulation among treatment groups. The initial differences in selected temperatures, as well as the shift in selected temperatures between first and second trials, demonstrate plasticity in temperature selection. As a previous study failed to find environmentally induced plasticity in temperature selection in adult A. carolinensis, this study suggests that this type of plasticity is exclusive to the period of neonatal development. (c) 2007 Wiley-Liss, Inc.

Assessment of Air Temperature Trends in the Source Region of Yellow River and Its Sub-Basins, China

NASA Astrophysics Data System (ADS)

Iqbal, Mudassar; Wen, Jun; Wang, Xin; Lan, Yongchao; Tian, Hui; Anjum, Muhammad Naveed; Adnan, Muhammad

2018-02-01

Changes in climatic variables at the sub-basins scale (having different features of land cover) are crucial for planning, development and designing of water resources infrastructure in the context of climate change. Accordingly, to explore the features of climate changes in sub-basins of the Source Region of Yellow River (SRYR), absolute changes and trends of temperature variables, maximum temperature (Tmax), minimum temperature (Tmin), mean temperature (Tavg) and diurnal temperature range (DTR), were analyzed annually and seasonally by using daily observed air temperature dataset from 1965 to 2014. Results showed that annual Tmax, Tmin and Tavg for the SRYR were experiencing warming trends respectively at the rate of 0.28, 0.36 and 0.31°C (10 yr)-1. In comparison with the 1st period (1965-1989), more absolute changes and trends towards increasing were observed during the 2nd period (1990-2014). Apart from Tangnaihai (a low altitude sub-basin), these increasing trends and changes seemed more significant in other basins with highest magnitude during winter. Among sub-basins the increasing trends were more dominant in Huangheyan compared to other sub-basins. The largest increase magnitude of Tmin, 1.24 and 1.18°C (10 yr)-1, occurred in high altitude sub-basins Jimai and Huangheyan, respectively, while the smallest increase magnitude of 0.23°C (10 yr)-1 occurred in a low altitude sub-basin Tangnaihai. The high elevation difference in Tangnaihai probably was the main reason for the less increase in the magnitude of Tmin. In the last decade, smaller magnitude of trend for all temperature variables signified the signal of cooling in the region. Overall, changes of temperature variables had significant spatial and seasonal variations. It implies that seasonal variations of runoff might be greater or different for each sub-basin.

Burrowing, byssus, and biomarkers: behavioral and physiological indicators of sublethal thermal stress in freshwater mussels (Unionidae)

USGS Publications Warehouse

Archambault, Jennifer M.; Cope, W. Gregory; Kwak, Thomas J.

2013-01-01

Recent research has elucidated the acute lethal effects of elevated water temperatures to glochidia (larvae), juvenile, and adult life stages of freshwater mussels (Order Unionida), but few studies have focused on sublethal effects of thermal stress. We evaluated the sublethal effects of elevated temperature on burrowing behavior and byssus production in juveniles, and on enzymatic biomarkers of stress in adults in acute (96 h) laboratory experiments in sediment, with two acclimation temperatures (22 and 27 °C) and two experimental water levels (watered and dewatered) as proxies for flow regime. Increasing temperature significantly reduced burrowing in all five species tested, and the dewatered treatment (a proxy for drought conditions) reduced burrowing in all but Amblema plicata. Production of byssal threads was affected most drastically by flow regime, with the probability of byssus presence reduced by 93–99% in the dewatered treatment, compared to the watered treatment (a proxy for low flow conditions); increasing temperature alone reduced byssus by 18–35%. Alanine aminotransferase and aspartate aminotransferase were significantly affected by treatment temperature in the 27 °C acclimation, watered test (p = 0.04 and 0.02, respectively). Our results are important in the context of climate change, because stream temperature and flow are expected to change with increasing air temperature and altered precipitation patterns.

Prophylactic augmentation of the proximal femur: an investigation of two techniques.

PubMed

Raas, Christoph; Hofmann-Fliri, Ladina; Hörmann, Romed; Schmoelz, Werner

2016-03-01

Osteoporotic hip fractures are an increasing problem in an ageing population. They result in high morbidity, mortality and high socioeconomic costs. For patients with poor bone quality, prophylactic augmentation of the proximal femur might be an option for fracture prevention. In two groups of paired human femora the potential of limited polymethyl-methacrylate (PMMA) augmentation (11-15 ml) in a V-shape pattern and the insertion of a proximal femur nail antirotation (PFNA) blade were investigated. The testing was carried out pair wise simulating the single leg stand. The untreated femur in each pair served as control. An axial load was applied until failure. Load displacement parameters and temperature increase during the augmentation process were recorded. In the PMMA group no significant difference was found between the augmented and non-augmented specimen concerning load to failure (p = 0.35) and energy to failure (p = 0.9). A median temperature increase of 9.5 °C was observed in the augmented specimen. A significant correlation was found between the amount of applied PMMA and the temperature increase (Cor. Coef. = 0.82, p = 0.042). In the PFNA group, a significant decrease of load to failure and a non-significant decrease of energy to failure were observed (p = 0.037 and p = 0.075). Limited V-shaped PMMA augmentation and PFNA blade insertion did not show any improvement in failure load or energy to failure. Volumes of up to 15 ml PMMA did not cause a critical surface temperature increase.

[Spectral Characteristics of Spring Maize Varieties with Different Heat Tolerance to High Temperature].

PubMed

Tao, Zhi-qiang; Chen, Yuan-quan; Zou, Juan-xiu; Li, Chao; Yuan, Shu-fen; Yan, Peng; Shi, Jiang-tao; Sui, Peng

2016-02-01

This paper discussed the response of spectral characteristics on high temperature at grain filling stage of different spring maize varieties by adopting two spectrometer (SPAD-502 Chlorophyll Meter and Sunscan Plant Canopy Analyzer), and analyzed the impact of high temperature on the photosynthetic properties of spring maize in North China Plain. The test was conductedfrom the year 2011 to 2012 in Wuqiao County, Hebei Province. This test chose three different varieties, i. e. Tianyu 198 (TY198), Xingyu 998 (XY998) and Tianrun 606 (TR606), then two sowing date (April 15th and April 25th) was set. We analyzed chlorophyll relative content (SPAD), leaf area index (LAI) and photosynthetically active radiation (PAR) at grain filling stage. The results showed that the days of daily maximum temperature above 33 °C and the mean day temperature at grain filling stage in spring maize sowing on April 15th increased 3.5 d and 0.8 °C, respectively, compared to that sowing on April 25th, moreover the sunshine hours, rainfall, diurnal temperature and length of growing period were similar. Compared with XY998 and TR606, TY198's stress tolerance indices (STI) increased by 2.9% and 11.0%, respectively. According to STI from high to low order, TY198, XY998 and TR606 respectively as heat resistant type, moderate heat resistant type and thermo-labile type variety. TY198, compared with XY998 and TR606 sowing on April 15th, yield increased by 4.1% and 13.7%, SPAD increased by 12.5% and 19.6%, LAI increased by 5.3% and 5.6%, PAR increased by 4.0% and 14.0%. Sowing on April 15th, yield increased by 1.3% and 2.8%, SPAD increased by 3.5% and 6.0%, LAI increased by 1.7% and 4.1%, PAR increased by -4.4% and 0.9%. Three varieties had significant yield differences in the environment of high temperature stress, heat resistant type have significant (p < 0.05) advantage in the aspect of yield, SPAD and LAI. The production of TY198, XY998 and TR606 sowing on April 15th compared to that sowing on April 25th decreased by 3.2%, 5.9% and 12.6%, and SPAD decreased by 8.6%, 12.4% and 15.7%, LAI decreased by 11.7%, 17.6% and 19.8%, PAR decreased by 3.4%, 11.3% and 14.5%; STI had a significant negatively correlated with SPAD fall range (r = -0.883, p < 0.05) and LAI fall range (r = -0.853, P < 0.05), and highly significantly negatively correlated with PAR fall range (r = -0.923, p < 0.01); while SPAD fall range and PAR fall range showed a significant positive correlation (r = 0.872, p < 0.05); LAI fall range and PAR fall range were significantly positive correlation (r = 0.943, p < 0.05). In conclusion, heat tolerant type varieties of spring maize under high temperature stress at gain filling stage could maintain a relatively high content of chlorophyll at the individual level, a relatively high leaf area at the group level, and then keep a higher luminous energy interception and utilization, and weakened inhibition magnitude of high temperature on photosynthetic capacity, reduced the yield fall range, then achieved high and stable yield. The heat tolerance in varieties could be one of the main indicators for identification and evaluation the response to high temperature by spectral characteristics (SPAD, LAI and PAR). Thus it provides a basis by using spectral characteristics to study heat tolerance on maize.

The effects of increased constant incubation temperature and cumulative acute heat shock exposures on morphology and survival of Lake Whitefish (Coregonus clupeaformis) embryos.

PubMed

Lee, Abigail H; Eme, John; Mueller, Casey A; Manzon, Richard G; Somers, Christopher M; Boreham, Douglas R; Wilson, Joanna Y

2016-04-01

Increasing incubation temperatures, caused by global climate change or thermal effluent from industrial processes, may influence embryonic development of fish. This study investigates the cumulative effects of increased incubation temperature and repeated heat shocks on developing Lake Whitefish (Coregonus clupeaformis) embryos. We studied the effects of three constant incubation temperatures (2°C, 5°C or 8°C water) and weekly, 1-h heat shocks (+3°C) on hatching time, survival and morphology of embryos, as these endpoints may be particularly susceptible to temperature changes. The constant temperatures represent the predicted magnitude of elevated water temperatures from climate change and industrial thermal plumes. Time to the pre-hatch stage decreased as constant incubation temperature increased (148d at 2°C, 92d at 5°C, 50d at 8°C), but weekly heat shocks did not affect time to hatch. Mean survival rates and embryo morphometrics were compared at specific developmental time-points (blastopore, eyed, fin flutter and pre-hatch) across all treatments. Constant incubation temperatures or +3°C heat-shock exposures did not significantly alter cumulative survival percentage (~50% cumulative survival to pre-hatch stage). Constant warm incubation temperatures did result in differences in morphology in pre-hatch stage embryos. 8°C and 5°C embryos were significantly smaller and had larger yolks than 2°C embryos, but heat-shocked embryos did not differ from their respective constant temperature treatment groups. Elevated incubation temperatures may adversely alter Lake Whitefish embryo size at hatch, but weekly 1-h heat shocks did not affect size or survival at hatch. These results suggest that intermittent bouts of warm water effluent (e.g., variable industrial emissions) are less likely to negatively affect Lake Whitefish embryonic development than warmer constant incubation temperatures that may occur due to climate change. Copyright © 2016 Elsevier Ltd. All rights reserved.

Numerical prediction of micro-channel LD heat sink operated with antifreeze based on CFD method

NASA Astrophysics Data System (ADS)

Liu, Gang; Liu, Yang; Wang, Chao; Wang, Wentao; Wang, Gang; Tang, Xiaojun

2014-12-01

To theoretically study the feasibility of antifreeze coolants applied as cooling fluids for high power LD heat sink, detailed Computational Fluid Dynamics (CFD) analysis of liquid cooled micro-channels heat sinks is presented. The performance operated with antifreeze coolant (ethylene glycol aqueous solution) compared with pure water are numerical calculated for the heat sinks with the same micro-channels structures. The maximum thermal resistance, total pressure loss (flow resistance), thermal resistance vs. flow-rate, and pressure loss vs. flow-rate etc. characteristics are numerical calculated. The results indicate that the type and temperature of coolants plays an important role on the performance of heat sinks. The whole thermal resistance and pressure loss of heat sinks increase significantly with antifreeze coolants compared with pure water mainly due to its relatively lower thermal conductivity and higher fluid viscosity. The thermal resistance and pressure loss are functions of the flow rate and operation temperature. Increasing of the coolant flow rate can reduce the thermal resistance of heat sinks; meanwhile increase the pressure loss significantly. The thermal resistance tends to a limit with increasing flow rate, while the pressure loss tends to increase exponentially with increasing flow rate. Low operation temperature chiefly increases the pressure loss rather than thermal resistance due to the remarkable increasing of fluid viscosity. The actual working point of the cooling circulation system can be determined on the basis of the pressure drop vs. flow rate curve for the micro-channel heat sink and that for the circulation system. In the same system, if the type or/and temperature of the coolant is changed, the working point is accordingly influenced, that is, working flow rate and pressure is changed simultaneously, due to which the heat sink performance is influenced. According to the numerical simulation results, if ethylene glycol aqueous solution is applied instead of pure water as the coolant under the same or a higher working temperature, the available output of optical power will decrease due to the worse heat sink performance; if applied under a lower working temperature(0 °C, －20 °C), although the heat sink performance become worse, however the temperature difference of heat transfer rises more significantly, the available output of optical power will increase on the contrary.

Short spell kangaroo mother care and its differential physiological influence in subgroups of preterm babies.

PubMed

Boju, Sangeetha Lakshmi; Gopi Krishna, Muddu; Uppala, Rajani; Chodavarapu, Praneeta; Chodavarapu, Ravikumar

2012-06-01

In routine practice, 4-6 h of kangaroo mother care (KMC) is adopted. Many mothers feel the duration impracticable. In 86 preterm babies, pre and post 1 h KMC changes in heart rate (HR), respiratory rate (RR), axillary temperature and SpO(2) are measured, in each baby. Postnatal age at the time of the study is 7.7 ± 5.2 days. Significant changes observed are decrease in mean HR by 3 bpm, RR by 3 min(-1) and increase in mean axillary temperature by 0.4 F and SpO(2) by 1.1%. In SGA babies, post KMC decrease in mean HR by 5 bpm, increase in mean axillary temperature by 0.6 F and SpO(2) by 2.1% are significant. In female babies, post KMC decrease in mean RR by 6 min(-1) and increase mean axillary temperature by 0.3 F and SpO(2) by 1.5% are significant. We conclude that preterm babies are benefited by 1 h KMC. SGA and female preterm babies showed different and greater response.

The effect of temperature on experimental and natural chemical weathering rates of granitoid rocks

USGS Publications Warehouse

White, A.F.; Blum, A.E.; Bullen, T.D.; Vivit, D.V.; Schulz, M.; Fitzpatrick, J.

1999-01-01

The effects of climatic temperature variations (5-35??C) on chemical weathering are investigated both experimentally using flow-through columns containing fresh and weathered granitoid rocks and for natural granitoid weathering in watersheds based on annual solute discharge. Although experimental Na and Si effluent concentrations are significantly higher in the fresh relative to the weathered granitoids, the proportional increases in concentration with increasing temperature are similar. Si and Na exhibit comparable average apparent activation energies (E(a)) of 56 and 61 kJ/mol, respectively, which are similar to those reported for experimental feldspar dissolution measured over larger temperature ranges. A coupled temperature-precipitation model, using an expanded database for solute discharge fluxes from a global distribution of 86 granitoid watersheds, produces an apparent activation energy for Si (51 kJ/mol), which is also comparable to those derived from the experimental study. This correlation reinforces evidence that temperature does significantly impact natural silicate weathering rates. Effluent K concentrations in the column study are elevated with respect to other cations compared to watershed discharge due to the rapid oxidation/dissolution of biotite. K concentrations are less sensitive to temperature, resulting in a lower average E(a) value (27 kJ/mol) indicative of K loss from lower energy interlayer sites in biotite. At lower temperatures, initial cation release from biotite is significantly faster than cation release from plagioclase. This agrees with reported higher K/Na ratios in cold glacial watersheds relative to warmer temperate environments. Increased release of less radiogenic Sr from plagioclase relative to biotite at increasing temperature produces corresponding decreases in 87Sr/86Sr ratios in the column effluents. A simple mixing calculation using effluent K/Na ratios, Sr concentrations and 87Sr/86Sr ratios for biotite and plagioclase approximates stoichiometric cation ratios from biotite/plagioclase dissolution at warmer temperatures (35??C), but progressively overestimates the relative proportion of biotite with decreasing temperature. Ca, Mg, and Sr concentrations closely correlate, exhibit no consistent trends with temperature, and are controlled by trace amounts of calcite or exchange within weathered biotite. The inability of the watershed model to differentiate a climate signal for such species correlates with the lower temperature dependence observed in the experimental studies.

Research on the effect of alkali roasting of copper dross on leaching rate of indium

NASA Astrophysics Data System (ADS)

Dafang, Liu; Fan, Xingxiang; Shi, Yifeng; Yang, Kunbin

2017-11-01

The byproduct copper dross produced during refining crude lead was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and fluorescence spectrometer (XRF), which showed that copper dross mainly contained lead, copper, zinc, arsenic, antimony, bismuth, sulfur and a small amount of indium and silver etc. The mineralogical phase change of oxidation roasting of copper dross by adding sodium hydroxide was analyzed with the help of XRD and SEM. The effects of water leaching, ratio of sodium hydroxide, roasting time, and roasting temperature on leaching rate of indium were investigated mainly. The experimental results showed that phase of lead metal and sulfides of lead, copper and zinc disappeared after oxidation roasting of copper dross by adding sodium hydroxide, new phase of oxides of lead, copper, zinc and sodium salt of arsenic and antimony appeared. Water leaching could remove arsenic, and acid leaching residue obtained was then leached with acid. The leaching rate of indium was higher 6.98% compared with alkali roasting of copper dross-acid leaching. It showed that removing arsenic by water leaching and acid leaching could increase the leaching rate of indium and be beneficial to reducing subsequent acid consumption of extracting indium by acid leaching. The roasting temperature had a significant effect on the leaching rate of indium, and leaching rate of indium increased with the rise of roasting temperature. When roasting temperature ranged from 450°C to 600°C, leaching rate of indium increased significantly with the rise of roasting temperature. When roasting temperature rose from 450°C to 600°C, leaching rate of indium increased by 60.29%. The amount of sodium hydroxide had an significant effect on the leaching rate of indium, and the leaching of indium increased with the increase of the amount of sodium hydroxide, and the leaching rate of indium was obviously higher than that of copper dross blank roasting and acid leaching.

Body mass modulates huddling dynamics and body temperature profiles in rabbit pups.

PubMed

Bautista, Amando; Zepeda, José Alfredo; Reyes-Meza, Verónica; Féron, Christophe; Rödel, Heiko G; Hudson, Robyn

2017-10-01

Altricial mammals typically lack the physiological capacity to thermoregulate independently during the early postnatal period, and in litter-bearing species the young benefit strongly from huddling together with their litter siblings. Such litter huddles are highly dynamic systems, often characterized by competition for energetically favorable, central positions. In the present study, carried out in domestic rabbits Oryctolagus cuniculus, we asked whether individual differences in body mass affect changes in body temperature during changes in the position within the huddle. We predicted that pups with relatively lower body mass should be more affected by such changes arising from huddle dynamics in comparison to heavier ones. Changes in pups' maximum body surface temperature (determined by infrared thermography) were significantly affected by changes in the number of their neighbors in the litter huddle, and indeed these temperature changes largely depended on the pups' body mass relative to their litter siblings. Lighter pups showed significant increases in their maximum body surface temperature when their number of huddling partners increased by one or two siblings whereas pups with intermediate or heavier body mass did not show such significant increases in maximum body temperature when experiencing such changes. A similar pattern was found with respect to average body surface temperature. This strong link between changes in the number of huddling partners and body surface temperature in lighter pups might, on the one hand, arise from a higher vulnerability of such pups due to their less favorable body surface area-to-volume ratio. On the other hand, as lighter pups generally had fewer neighbors than heavier ones and thus typically a comparatively smaller body surface in contact with siblings, they potentially had more to gain from increasing their number of neighbors. The present findings might help to understand how individual differences in body mass within a litter lead to the emergence of individual differences in sibling interactions during early postnatal life in different species of altricial and litter-bearing mammals. Copyright © 2017 Elsevier Inc. All rights reserved.

Is warmer better? Decreased oxidative damage in notothenioid fish after long-term acclimation to multiple stressors.

PubMed

Enzor, Laura A; Place, Sean P

2014-09-15

Antarctic fish of the suborder Notothenioidei have evolved several unique adaptations to deal with subzero temperatures. However, these adaptations may come with physiological trade-offs, such as an increased susceptibility to oxidative damage. As such, the expected environmental perturbations brought on by global climate change have the potential to significantly increase the level of oxidative stress and cellular damage in these endemic fish. Previous single stressor studies of the notothenioids have shown they possess the capacity to acclimate to increased temperatures, but the cellular-level effects remain largely unknown. Additionally, there is little information on the ability of Antarctic fish to respond to ecologically relevant environmental changes where multiple variables change concomitantly. We have examined the potential synergistic effects that increased temperature and Ṗ(CO2) have on the level of protein damage in Trematomus bernacchii, Pagothenia borchgrevinki and Trematomus newnesi, and combined these measurements with changes in total enzymatic activity of catalase (CAT) and superoxide dismutase (SOD) in order to gauge tissue-specific changes in antioxidant capacity. Our findings indicate that total SOD and CAT activity levels displayed only small changes across treatments and tissues. Short-term acclimation to decreased seawater pH and increased temperature resulted in significant increases in oxidative damage. Surprisingly, despite no significant change in antioxidant capacity, cellular damage returned to near-basal levels, and significantly decreased in T. bernacchii, after long-term acclimation. Overall, these data suggest that notothenioid fish currently maintain the antioxidant capacity necessary to offset predicted future ocean conditions, but it remains unclear whether this capacity comes with physiological trade-offs. © 2014. Published by The Company of Biologists Ltd.

High-Resolution Dynamical Downscaling Ensemble Projections of Future Extreme Temperature Distributions for the United States

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

Zobel, Zachary; Wang, Jiali; Wuebbles, Donald J.

The aim of this study is to examine projections of extreme temperatures over the continental United States (CONUS) for the 21st century using an ensemble of high spatial resolution dynamically downscaled model simulations with different boundary conditions. The downscaling uses the Weather Research and Forecast model at a spatial resolution of 12 km along with outputs from three different Coupled Model Intercomparison Project Phase 5 global climate models that provide boundary con- ditions under two different future greenhouse gas (GHG) concentration trajectories. The results from two decadal-length time slices (2045–2054 and 2085–2094) are compared with a historical decade (1995–2004). Probabilitymore » density functions of daily maximum/minimum temperatures are analyzed over seven climatologically cohesive regions of the CONUS. The impacts of different boundary conditions as well as future GHG concentrations on extreme events such as heat waves and days with temperature higher than 95°F are also investigated. The results show that the intensity of extreme warm temperature in future summer is significantly increased, while the frequency of extreme cold temperature in future winter decreases. The distribution of summer daily maximum temperature experiences a significant warm-side shift and increased variability, while the distribution of winter daily minimum temperature is projected to have a less significant warm-side shift with decreased variability. Finally, using "business-as-usual" scenario, 5-day heat waves are projected to occur at least 5–10 times per year in most CONUS and ≥ 95°F days will increase by 1–2 months by the end of the century.« less

Trend analysis of air temperature and precipitation time series over Greece: 1955-2010

NASA Astrophysics Data System (ADS)

Marougianni, G.; Melas, D.; Kioutsioukis, I.; Feidas, H.; Zanis, P.; Anandranistakis, E.

2012-04-01

In this study, a database of air temperature and precipitation time series from the network of Hellenic National Meteorological Service has been developed in the framework of the project GEOCLIMA, co-financed by the European Union and Greek national funds through the Operational Program "Competitiveness and Entrepreneurship" of the Research Funding Program COOPERATION 2009. Initially, a quality test was applied to the raw data and then missing observations have been imputed with a regularized, spatial-temporal expectation - maximization algorithm to complete the climatic record. Next, a quantile - matching algorithm was applied in order to verify the homogeneity of the data. The processed time series were used for the calculation of temporal annual and seasonal trends of air temperature and precipitation. Monthly maximum and minimum surface air temperature and precipitation means at all available stations in Greece were analyzed for temporal trends and spatial variation patterns for the longest common time period of homogenous data (1955 - 2010), applying the Mann-Kendall test. The majority of the examined stations showed a significant increase in the summer maximum and minimum temperatures; this could be possibly physically linked to the Etesian winds, because of the less frequent expansion of the low over the southeastern Mediterranean. Summer minimum temperatures have been increasing at a faster rate than that of summer maximum temperatures, reflecting an asymmetric change of extreme temperature distributions. Total annual precipitation has been significantly decreased at the stations located in western Greece, as well as in the southeast, while the remaining areas exhibit a non-significant negative trend. This reduction is very likely linked to the positive phase of the NAO that resulted in an increase in the frequency and persistence of anticyclones over the Mediterranean.

High-Resolution Dynamical Downscaling Ensemble Projections of Future Extreme Temperature Distributions for the United States

DOE PAGES

Zobel, Zachary; Wang, Jiali; Wuebbles, Donald J.; ...

2017-11-20

The aim of this study is to examine projections of extreme temperatures over the continental United States (CONUS) for the 21st century using an ensemble of high spatial resolution dynamically downscaled model simulations with different boundary conditions. The downscaling uses the Weather Research and Forecast model at a spatial resolution of 12 km along with outputs from three different Coupled Model Intercomparison Project Phase 5 global climate models that provide boundary con- ditions under two different future greenhouse gas (GHG) concentration trajectories. The results from two decadal-length time slices (2045–2054 and 2085–2094) are compared with a historical decade (1995–2004). Probabilitymore » density functions of daily maximum/minimum temperatures are analyzed over seven climatologically cohesive regions of the CONUS. The impacts of different boundary conditions as well as future GHG concentrations on extreme events such as heat waves and days with temperature higher than 95°F are also investigated. The results show that the intensity of extreme warm temperature in future summer is significantly increased, while the frequency of extreme cold temperature in future winter decreases. The distribution of summer daily maximum temperature experiences a significant warm-side shift and increased variability, while the distribution of winter daily minimum temperature is projected to have a less significant warm-side shift with decreased variability. Finally, using "business-as-usual" scenario, 5-day heat waves are projected to occur at least 5–10 times per year in most CONUS and ≥ 95°F days will increase by 1–2 months by the end of the century.« less

The effects of temperature and exercise training on swimming performance in juvenile qingbo (Spinibarbus sinensis).

PubMed

Pang, Xu; Yuan, Xing-Zhong; Cao, Zhen-Dong; Fu, Shi-Jian

2013-01-01

To investigate the effects of temperature and exercise training on swimming performance in juvenile qingbo (Spinibarbus sinensis), we measured the following: (1) the resting oxygen consumption rate (MO(2rest)), critical swimming speed (U(crit)) and active oxygen consumption rate (MO(2active)) of fish at acclimation temperatures of 10, 15, 20, 25 and 30 °C and (2) the MO(2rest), U(crit) and MO(2active) of both exercise-trained (exhaustive chasing training for 14 days) and control fish at both low and high acclimation temperatures (15 and 25 °C). The relationship between U(crit) and temperature (T) approximately followed a bell-shaped curve as temperature increased: U(crit) = 8.21/{1 + [(T - 27.2)/17.0]²} (R² = 0.915, P < 0.001, N = 40). The optimal temperature for maximal U(crit) (8.21 BL s(-1)) in juvenile qingbo was 27.2 °C. Both the MO(2active) and the metabolic scope (MS, MO(2active) - MO(2rest)) of qingbo increased with temperature from 10 to 25 °C (P < 0.05), but there were no significant differences between fish acclimated to 25 and 30 °C. The relationships between MO(2active) or MS and temperature were described as MO(2active) = 1,214.29 /{1 + [(T - 28.8)/10.6]²} (R² = 0.911, P < 0.001, N = 40) and MS = 972.67/{1 + [(T - 28.0)/9.34]²} (R² = 0.878, P < 0.001, N = 40). The optimal temperatures for MO(2active) and MS in juvenile qingbo were 28.8 and 28.0 °C, respectively. Exercise training resulted in significant increases in both U(crit) and MO(2active) at a low temperature (P < 0.05), but training exhibited no significant effect on either U(crit) or MO(2active) at a high temperature. These results suggest that exercise training had different effects on swimming performance at different temperatures. These differences may be related to changes in aerobic metabolic capability, arterial oxygen delivery, available dissolved oxygen, imbalances in ion fluxes and stimuli to remodel tissues with changes in temperature.

Effect of temperature stress on circulating biogenic amines in bovine.

PubMed

Davis, T P; Johnson, H D; Gehrke, C W

1984-01-01

A sensitive, simple and selective chromatographic method using high performance liquid chromatography was developed to measure circulating levels of histamine (HI), norepinephrine (NE), dopamine (DA) and serotonin (5-HT) as indicators of response to thermal stress in two breeds of cattle. Duplicate exposures for 8 hr to 13 degrees C resulted in significantly elevated plasma NE and DA in longhorns but not in Herefords and suggest a relatively greater sensitivity to the cold (13 degrees C) in the longhorn. Environmental temperatures of 32 and 42 degrees C significantly increased rectal temperatures of both breeds with much higher rectal temperatures in Herefords. The 32 and 42 degrees C effects on circulating NE and DA of Herefords were highly significant but not in the longhorn. However, heat stress significantly elevated HI and 5-HT in the longhorn which may account for their relatively greater heat tolerance based on their lower rectal temperatures.

Long-term trend analysis of reservoir water quality and quantity at the landscape scale in two major river basins of Texas, USA.

USGS Publications Warehouse

Patino, Reynaldo; Asquith, William H.; VanLandeghem, Matthew M.; Dawson, D.

2016-01-01

Trends in water quality and quantity were assessed for 11 major reservoirs of the Brazos and Colorado river basins in the southern Great Plains (maximum period of record, 1965–2010). Water quality, major contributing-stream inflow, storage, local precipitation, and basin-wide total water withdrawals were analyzed. Inflow and storage decreased and total phosphorus increased in most reservoirs. The overall, warmest-, or coldest-monthly temperatures increased in 7 reservoirs, decreased in 1 reservoir, and did not significantly change in 3 reservoirs. The most common monotonic trend in salinity-related variables (specific conductance, chloride, sulfate) was one of no change, and when significant change occurred, it was inconsistent among reservoirs. No significant change was detected in monthly sums of local precipitation. Annual water withdrawals increased in both basins, but the increase was significant (P < 0.05) only in the Colorado River and marginally significant (P < 0.1) in the Brazos River. Salinity-related variables dominated spatial variability in water quality data due to the presence of high- and low-salinity reservoirs in both basins. These observations present a landscape in the Brazos and Colorado river basins where, in the last ∼40 years, reservoir inflow and storage generally decreased, eutrophication generally increased, and water temperature generally increased in at least 1 of 3 temperature indicators evaluated. Because local precipitation remained generally stable, observed reductions in reservoir inflow and storage during the study period may be attributable to other proximate factors, including increased water withdrawals (at least in the Colorado River basin) or decreased runoff from contributing watersheds.

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.

Optimization of β-casein stabilized nanoemulsions using experimental mixture design.

PubMed

Maher, Patrick G; Fenelon, Mark A; Zhou, Yankun; Kamrul Haque, Md; Roos, Yrjö H

2011-10-01

The objective of this study was to determine the effect of changing viscosity and glass transition temperature in the continuous phase of nanoemulsion systems on subsequent stability. Formulations comprising of β-casein (2.5%, 5%, 7.5%, and 10% w/w), lactose (0% to 20% w/w), and trehalose (0% to 20% w/w) were generated from Design of Experiments (DOE) software and tested for glass transition temperature and onset of ice-melting temperature in maximally freeze-concentrated state (T(g) ' & T(m) '), and viscosity (μ). Increasing β-casein content resulted in significant (P < 0.0001) increases in viscosity and T(m) ' (P= 0.0003), and significant (P < 0.0001) decreases in T(g) '. A mixture design was used to predict the optimum levels of lactose and trehalose required to attain the minimum and maximum T(g) ' and viscosity in solution at fixed protein contents. These mixtures were used to form the continuous phase of β-casein stabilized nanoemulsions (10% w/w sunflower oil) prepared by microfluidization at 70 MPa. Nanoemulsions were analyzed for T(g) ' & T(m) ', as well as viscosity, mean particle size, and stability. Increasing levels of β-casein (2.5% to 10% w/w) resulted in a significant (P < 0.0001) increase in viscosity (5 to 156 mPa.s), significant increase in particle size (P= 0.0115) from 186 to 199 nm, and significant decrease (P= 0.0001) in T(g) ' (-45 to -50 °C). Increasing the protein content resulted in a significant (P < 0.0001) increase in nanoemulsion stability. A mixture DOE was successfully used to predict glass transition and rheological properties for development of a continuous phase for use in nanoemulsions. © 2011 Institute of Food Technologists®

A Fiber Bragg Grating Temperature Sensor for 2-400 K

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

Zaynetdinov, Madrakhim; See, Erich M.; Geist, Brian

2015-03-01

We demonstrate fiber optic, multiplexible temperature sensing using a fiber Bragg grating (FBG) with an operational range of 2-400 K, and a temperature resolution better than 10 mK for temperatures < 12 K. This represents a significant reduction in the lowest usable temperature as well as a significant increase in sensitivity at cryogenic temperatures compared with previously reported multiplexible solutions. This is accomplished by mounting the section of the fiber with a FBG on a polytetrafluoroethylene coupon, which has a non-negligible coefficient of thermal expansion down to < 4 K. The sensors exhibit a good stability over multiple temperature cyclesmore » and acceptable sensor-to-sensor repeatability. Possible applications for this sensor include distributed temperature sensing across superconducting elements and cryogenic temperature measurements in environments where electrical measurements are impractical or unsafe.« less

Effects of a ceramic coating on metal temperatures of an air-cooled turbine vane

NASA Astrophysics Data System (ADS)

Gladden, H. J.; Liebert, C. H.

1980-02-01

The metal temperatures of air cooled turbine vanes both uncoated and coated with the NASA thermal barrier system were studied experimentally. Current and advanced gas turbine engine conditions were simulated at reduced temperatures and pressures. Airfoil metal temperatures were significantly reduced, both locally and on the average, by use of the the coating. However, at low gas Reynolds number, the ceramic coating tripped a laminar boundary layer on the suction surface, and the resulting higher heat flux increased the metal temperatures. Simulated coating loss was also investigated and shown to increase local metal temperatures. However, the metal temperatures in the leading edge region remained below those of the uncoated vane tested at similar conditions. Metal temperatures in the trailing edge region exceeded those of the uncoated vane.

Effects of a ceramic coating on metal temperatures of an air-cooled turbine vane

NASA Technical Reports Server (NTRS)

Gladden, H. J.; Liebert, C. H.

1980-01-01

The metal temperatures of air cooled turbine vanes both uncoated and coated with the NASA thermal barrier system were studied experimentally. Current and advanced gas turbine engine conditions were simulated at reduced temperatures and pressures. Airfoil metal temperatures were significantly reduced, both locally and on the average, by use of the the coating. However, at low gas Reynolds number, the ceramic coating tripped a laminar boundary layer on the suction surface, and the resulting higher heat flux increased the metal temperatures. Simulated coating loss was also investigated and shown to increase local metal temperatures. However, the metal temperatures in the leading edge region remained below those of the uncoated vane tested at similar conditions. Metal temperatures in the trailing edge region exceeded those of the uncoated vane.

Sloths like it hot: ambient temperature modulates food intake in the brown-throated sloth (Bradypus variegatus)

PubMed Central

Haupt, Ryan J.; Avey-Arroyo, Judy A.; Wilson, Rory P.

2015-01-01

Sloths are considered to have one of the lowest mass-specific metabolic rates of any mammal and, in tandem with a slow digestive rate, have been theorized to have correspondingly low rates of ingestion. Here, we show in a study conducted over five months, that three captive Bradypus variegatus (Brown-throated sloths) had a remarkably low mean food intake of 17 g kg−1day−1 (SD 4.2). Food consumption was significantly affected by ambient temperature, with increased intake at higher temperatures. We suggest that the known fluctuation of sloth core body temperature with ambient temperature affects the rate at which gut fauna process digesta, allowing for increased rates of fermentation at higher temperatures. Since Bradypus sloths maintain a constantly full stomach, faster rates of fermentation should enhance digestive throughput, increasing the capacity for higher levels of food intake, thereby allowing increased energy acquisition at higher ambient temperatures. This contrasts with other mammals, which tend to show increased levels of food intake in colder conditions, and points to the importance of temperature in regulating all aspects of energy use in sloths. PMID:25861559

[Effects of elevated temperature on soil organic carbon and soil respiration under subalpine coniferous forest in western Sichuan Province, China].

PubMed

Pan, Xin-li; Lin, Bo; Liu, Qing

2008-08-01

To investigate the effects of elevated temperature on the soil organic carbon content, soil respiration rate, and soil enzyme activities in subalpine Picea asperata plantations in western Sichuan Province of China, a simulation study was conducted in situ with open-top chambers from November 2005 to July 2007. The results showed that under elevated temperature, the mean air temperature and soil temperature were 0.42 degrees C and 0.25 degrees C higher than the control, respectively. In the first and the second year, the increased temperature had somewhat decreasing effects on the soil organic carbon and the C/N ratio at the soil depths of 0-10 cm and 10-20 cm. In the first year the soil organic carbon and the C/N ratio in 0-10 cm soil layer decreased by 8.69%, and 8.52%, respectively; but in the second year, the decrements were lesser. Soil respiration rate was significantly enhanced in the first year of warming, but had no significant difference with the control in the second year. In the first year of warming, the activities of soil invertase, polyphenol oxidase, catalase, protease, and urease increased, and the invertase and polyphenol oxidase activities in 0-10 cm soil layer were significantly higher than the control. In the second year of warming, the activities of invertase, protease and urease still had an increase, but those of catalase and polyphenol oxidase had a downtrend, compared with the control.

High Temperature Oxidation and Mechanical properties of Silicon Nitride.

DTIC Science & Technology

1980-11-30

The results of thermogravimentric studies on the rate of oxidation of chemically vapor-deposited Si3 N, at various temperatures are reported. Up to...only be such ceramics as Si3N4 -. In addition to the potential for increased engine efficiency through higher gas-inlet temperatures, the use of Si3 N...to replace cur- rently used Ni -or Co-based superalloys offers a significant weight reduction that can increase the performance of the propulsion system

Perkinsus marinus, a protozoan parasite of the Eastern oyster (Crassostrea virginica): effects of temperature on the uptake and metabolism of fluorescent lipid analogs and lipase activities.

PubMed

Chu, Fu-Lin E; Soudant, P; Lund, E D

2003-10-01

The effects of temperature on the uptake and metabolism of fluorescent labeled palmitic acid (FLC16) and phosphatidylcholine (FLPC) and lipase activities in the oyster protozoan parasite, Perkinsus marinus, meront stage were tested at 10, 18, and 28 degrees C. Temperature significantly affected not only the uptake, assimilation, and metabolism of both FLC16 and FLPC in P. marinus, but also its triacylglycerol (TAG) lipase activities. The incorporation of both FLC16 and FLPC increased with temperature and paralleled the increase in the amount of total fatty acids in P. marinus meront cultures. The incorporation of FLC16 was higher than FLPC at all temperatures. The percentage of FLC16 metabolized to TAG was significantly higher at higher temperatures. Trace amounts of incorporated FLC16 were detected in monoacylglycerol (MAG) and PC at 18 and 28 degrees C. P. marinus meronts metabolized FLPC to TAG, diacylglycerol (DAG), monoacylglycerol (MAG), free fatty acids (FFA), phosphatidylethanolamine (PE), and cardiolipin (CL). The conversion of FLPC to TAG and PE was highest at 28 degrees C. The relative proportions of individual fatty acids and total saturated, monounsaturated and polyunsaturated fatty acids changed with temperatures. While total saturated fatty acids (SAFAs) increased with temperature, total monounsaturated fatty acids (MUFAs) decreased with temperature. Total polyunsaturated fatty acids (PUFAs) increased from 28 to 18 degrees C. The findings of increase of total SAFAs and decrease of total MUFAs with the increase of temperatures and upward shift of total PUFAs from 28 to 18 degrees C suggest that, as in other organisms, P. marinus is capable of adapting to changes in environmental temperatures by modifying its lipid metabolism. Generally, higher lipase activities were noted at higher cultivation temperatures. Both TAG lipase and phospholipase activities were detected in P. marinus cells and their extra cellular products (ECP), but phospholipase activities in both the cell pellets and ECP were very low. Also, lipase activities were much lower in ECP than in the cells. The observations of low metabolism, bioconversion of incorporated fluorescent lipid analogs and lipase activities at low temperatures are consistent with the low in vitro growth rate and low infectivity of P. marinus at low temperatures.

Measured solubilities and speciations from oversaturation experiments of neptunium, plutonium, and americium in UE-25p No. 1 well water from the Yucca Mountain region: Milestone report 3329-WBS1.2.3.4.1.3.1

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

Nitsche, H.; Roberts, K.; Prussin, T.

1994-04-01

Solubility and speciation are important in understanding aqueous radionuclide transport through the geosphere. They define the source term for transport retardation processes such as sorption and colloid formation. Solubility and speciation data are useful in verifying the validity of geochemical codes that are a part of predictive transport models. Results are presented from solubility and speciation experiments of {sup 237}NpO{sub 2}{sup +}, {sup 239}Pu{sup 4+}, and {sup 241}Am{sup 3+}/Nd{sup 3+} in a modified UE-25p No. 1 groundwater (from the Yucca Mountain region, Nevada, which is being investigated as a potential high-level nuclear waste disposal site) at two different temperatures (25{degree}more » and 60{degree}C) and three pH values (6.0, 7.0, 8.5). The solubility-controlling steady-state solids were identified and the speciation and/or oxidation states present in the supernatant solutions were determined. The neptunium solubility decreased with increasing temperature and pH. Plutonium concentrations significantly decreased with increasing temperature at pH 6 and 7. The concentration at pH 8.5 hardly decreased at all with increasing temperature. At both temperatures the concentrations were highest at pH 8.5, lowest at pH 7, and in between at pH 6. For the americium/neodymium solutions, the solubility decreased significantly with increasing temperature and increased somewhat with increasing pH.« less

Behaviour of aqueous sulfamethizole solution and temperature effects in cold plasma oxidation treatment.

PubMed

Sokolov, Alexander; Louhi-Kultanen, Marjatta

2018-06-07

The increase in volume and variety of pharmaceuticals found in natural water bodies has become an increasingly serious environmental problem. The implementation of cold plasma technology, specifically gas-phase pulsed corona discharge (PCD), for sulfamethizole abatement was studied in the present work. It was observed that sulfamethizole is easily oxidized by PCD. The flow rate and pH of the solution have no significant effect on the oxidation. Treatment at low pulse repetition frequency is preferable from the energy efficiency point of view but is more time-consuming. The maximum energy efficiency was around 120 g/kWh at half-life and around 50 g/kWh at the end of the treatment. Increasing the solution temperature from room temperature to 50 °C led to a significant reaction retardation of the process and decrease in energy efficiency. The pseudo-first order reaction rate constant (k 1 ) grows with increase in pulse repetition frequency and does not depend on pH. By contrast, decreasing frequency leads to a reduction of the second order reaction rate constant (k 2 ). At elevated temperature of 50 °C, the k 1 , k 2 values decrease 2 and 2.9 times at 50 pps and 500 pps respectively. Lower temperature of 10 °C had no effect on oxidation efficiency compared with room temperature.

Efficacy of Wrist/Palm Warming as an EVA Countermeasure to Maintain Finger Comfort in Cold Conditions During EVA

NASA Technical Reports Server (NTRS)

Koscheyev, Victor S.; Leon, Gloria R.; Trevino, Robert C.

2000-01-01

This study explored the effectiveness of local wrist/palm warming as a potential countermeasure for providing finger comfort during extended duration EVA. Methods: Six subjects (5 males and 1 female) were evaluated in a sagitally divided liquid cooling/warming garment (LCWG) with modified liquid cooling/warming (LCW) gloves in three different experimental conditions. Condition 1: Stage 1- no LCWG; chamber adaptation with LCW glove inlet water temperature 33 C; Stage 2-LCW glove inlet water temperature cooled to 8 C; Stage 3-LCW glove inlet water temperature warmed to 45 C; Condition 2: Stage1-LCWG and LCW glove inlet water temperature 33 C; Stage 2-LCWG inlet temperature cooled to 31 C, LCW gloves, 8 C; Stage 3-LCWG inlet water temperature remains at 31 C, LCW glove inlet water temperature warmed to 45 C; Condition 3: Stage l -LCWG and LCW gloves 33 C; Stage 2-LCWG inlet water temperature cooled to 28 C, LCW gloves, 8 C; Stage 3-LCWG remains at 28 C, LCW glove water temperature warmed to 45 C. Results: Wrist/palm area warming significantly increased finger temperature (Tfing) and blood perfusion in Stage 3 compared to Stage 2. The LCW gloves were most effective in increasing Stage 3 Tfing in Condition 1; and in increasing blood perfusion in Conditions 1 and 2 compared to Condition 3. Ratings of subjective perception of heat in the hand and overall body heat were higher at Stage 3 than Stage 2, with no significant differences across Conditions. Conclusions: Local wrist/palm warming was effective in increasing blood circulation to the distal extremities, suggesting the potential usefulness of this technique for increasing astronaut thermal comfort during EVA while decreasing power requirements. The LCW gloves were effective in heating the highly cooled fingers when the overall body was in a mild heat deficit.

Temperature-related mortality in 17 large Chinese cities: how heat and cold affect mortality in China.

PubMed

Ma, Wenjuan; Chen, Renjie; Kan, Haidong

2014-10-01

Few multicity studies have been conducted to investigate the acute health effects of cold and hot temperatures in China. We aimed to examine the relationship between temperature and daily mortality in 17 large Chinese cities. We first calculated city-specific effect of temperature using time-series regression models combined with distributed lag nonlinear models; then we pooled the city-specific estimates with the Bayesian hierarchical models. The cold effects lasted longer than the hot effects. For the cold effects, a 1 °C decrease from the 25th to 1st percentiles of temperature over lags 0-14 days was associated with increases of 1.69% [95% posterior intervals (PI): 1.01%, 2.36%], 2.49% (95% PI: 1.53%, 3.46%) and 1.60% (95% PI: 0.32%, 2.87%) in total, cardiovascular and respiratory mortality, respectively. For the hot effects, a 1 °C increase from the 75th to 99th percentiles of temperature was associated with corresponding increases of 2.83% (95% PI: 1.42%, 4.24%), 3.02% (95% PI: 1.33%, 4.71%) and 4.64% (95% PI: 1.96%, 7.31%). The latitudes, number of air conditioning per household and disposable income per capita were significant modifiers for cold effects; the proportion of the elderly was a significant modifier for hot effects. This largest epidemiological study of temperature to date in China suggested that both cold and hot temperatures were associated with increased mortality. Our findings may have important implications for the public health policies in China. Copyright © 2014 Elsevier Inc. All rights reserved.

Temperature and Precipitation trends in Kashmir valley, North Western Himalayas

NASA Astrophysics Data System (ADS)

Shafiq, Mifta Ul; Rasool, Rehana; Ahmed, Pervez; Dimri, A. P.

2018-01-01

Climate change has emerged as an important issue ever to confront mankind. This concern emerges from the fact that our day-to-day activities are leading to impacts on the Earth's atmosphere that has the potential to significantly alter the planet's shield and radiation balance. Developing countries particularly whose income is particularly derived from agricultural activities are at the forefront of bearing repercussions due to changing climate. The present study is an effort to analyze the changing trends of precipitation and temperature variables in Kashmir valley along different elevation zones in the north western part of India. As the Kashmir valley has a rich repository of glaciers with its annual share of precipitation, slight change in the temperature and precipitation regime has far reaching environmental and economic consequences. The results from Indian Meteorological Department (IMD) data of the period 1980-2014 reveals that the annual mean temperature of Kashmir valley has increased significantly. Accelerated warming has been observed during 1980-2014, with intense warming in the recent years (2001-2014). During the period 1980-2014, steeper increase, in annual mean maximum temperature than annual mean minimum temperature, has been observed. In addition, mean maximum temperature in plain regions has shown higher rate of increase when compared with mountainous areas. In case of mean minimum temperature, mountainous regions have shown higher rate of increase. Analysis of precipitation data for the same period shows a decreasing trend with mountainous regions having the highest rate of decrease which can be quite hazardous for the fragile mountain environment of the Kashmir valley housing a large number of glaciers.

Variability and trends of wet season temperature in the Sudano-Sahelian zone and relationships with precipitation

NASA Astrophysics Data System (ADS)

Oueslati, Boutheina; Camberlin, Pierre; Zoungrana, Joël; Roucou, Pascal; Diallo, Saliou

2018-02-01

The relationships between precipitation and temperature in the central Sudano-Sahelian belt are investigated by analyzing 50 years (1959-2008) of observed temperature (Tx and Tn) and rainfall variations. At daily time-scale, both Tx and Tn show a marked decrease as a response to rainfall occurrence, with a strongest departure from normal 1 day after the rainfall event (-0.5 to -2.5 °C depending on the month). The cooling is slightly larger when heavy rainfall events (>5 mm) are considered. The temperature anomalies weaken after the rainfall event, but are still significant several days later. The physical mechanisms accounting for the temperature response to precipitation are analysed. The Tx drop is accounted for by reduced incoming solar radiation associated with increased cloud cover and increased surface evaporation following surface moistening. The effect of evaporation becomes dominant a few days after the rainfall event. The reduced daytime heat storage and the subsequent sensible heat flux result in a later negative Tn anomaly. The effect of rainfall variations on temperature is significant for long-term warming trends. The rainfall decrease experienced between 1959 and 2008 accounts for a rainy season Tx increase of 0.15 to 0.3 °C, out of a total Tx increase of 1.3 to 1.5 °C. These results have strong implications on the assessment of future temperature changes. The dampening or amplifying effects of precipitation are determined by the sign of future precipitation trends. Confidence on temperature changes under global warming partly depend on the robustness of precipitation projections.

Combined effects of temperature and ocean acidification on the juvenile individuals of the mussel Mytilus chilensis

NASA Astrophysics Data System (ADS)

Duarte, C.; Navarro, J. M.; Acuña, K.; Torres, R.; Manríquez, P. H.; Lardies, M. A.; Vargas, C. A.; Lagos, N. A.; Aguilera, V.

2014-01-01

Anthropogenic CO2 emissions have led to increasing global mean temperatures (a process called global warming) and ocean acidification. Because both processes are occurring simultaneously, to better understand their consequences on marine species their combined effects must be experimentally evaluated. The aim of this study was to evaluate for the first time the combined effects of ocean acidification and water temperature increase on the total calcification rate, growth rate and survival of juvenile individuals of the mytilid mussel Mytilus chilensis (Hupe). Two temperature levels (12 and 16 °C) and three nominal CO2 concentrations (390, 700 and 1000 ppm of CO2) were used. We found that the net rate of calcium deposition and total weight were not significantly affected by temperature, but were negatively affected by the levels of CO2. The interactive effects of temperature and CO2 levels affected only the shell dissolution, but this process was not important for the animal's net calcification. These results suggest that individuals of M. chilensis are able to overcome increased temperatures, but not increments of CO2 levels. It is well known that mussels influence their physical and biological surroundings. Therefore, the negative effects of a CO2 increase could have significant ecological consequences, mainly in those habitats where this group is dominant in terms of abundance and biomass. Finally, taking into account that this species inhabit a wide geographic range, with contrasting environmental conditions (e.g., temperature, salinity and, pH), further studies are needed to evaluate the intraspecific variability in the responses of this species to different environmental stressors.

Low temperature stress on the hematological parameters and HSP gene expression in the turbot Scophthalmus maximus

NASA Astrophysics Data System (ADS)

Ji, Liqin; Jiang, Keyong; Liu, Mei; Wang, Baojie; Han, Longjiang; Zhang, Mingming; Wang, Lei

2016-05-01

To study the effect of low temperature stress on hematological parameters and HSP gene expression in the turbot ( Scophthalmus maximus), water temperature was lowered rapidly from 18 to 1°C. During the cooling process, three individuals were removed from culture tanks at 18, 13, 8, 5, 3, and 1°C. Blood samples and tissues were taken from each individual, hematological indices and HSP gene expression in tissues were measured. The red blood cell count, white blood cell count, and hemoglobin concentration decreased significantly ( P < 0.05) as temperature decreased. Enzyme activities of plasma alanine transaminase and creatine kinase increased as temperature decreased, whereas aspartic transaminase and γ-glutamyl transpeptidase activities displayed no obvious changes above 1°C and lactate dehydrogenase activity increased first and then decreased. Blood urea nitrogen and uric acid levels were highest at 8°C, and creatinine concentration was highest at 3°C. The concentrations of plasma cortisol, cholesterol, and triglyceride all increased significantly ( P < 0.05) as temperature decreased. The serum glucose concentration increased first and then decreased to the initial level. The HSP70 mRNA expression showed various patterns in different tissues, whereas HSP90 mRNA expression showed the same tendency in all tissues. Overall, these results indicate that temperature decreases in the range of 8 to 5°C may induce a stress response in S. maximus and that temperature should be kept above 8°C in the aquaculture setting to avoid damage to the fish.

High Temperature and Salinity Enhance Soil Nitrogen Mineralization in a Tidal Freshwater Marsh

PubMed Central

Gao, Haifeng; Bai, Junhong; He, Xinhua; Zhao, Qingqing; Lu, Qiongqiong; Wang, Junjing

2014-01-01

Soil nitrogen (N) mineralization in wetlands is sensitive to various environmental factors. To compare the effects of salinity and temperature on N mineralization, wetland soils from a tidal freshwater marsh locating in the Yellow River Delta was incubated over a 48-d anaerobic incubation period under four salinity concentrations (0, 10, 20 and 35‰) and four temperature levels (10, 20, 30 and 40°C). The results suggested that accumulated ammonium nitrogen (NH4 +-N) increased with increasing incubation time under all salinity concentrations. Higher temperatures and salinities significantly enhanced soil N mineralization except for a short-term (≈10 days) inhibiting effect found under 35‰ salinity. The incubation time, temperature, salinity and their interactions exhibited significant effects on N mineralization (P<0.001) except the interactive effect of salinity and temperature (P>0.05), while temperature exhibited the greatest effect (P<0.001). Meanwhile, N mineralization processes were simulated using both an effective accumulated temperature model and a one-pool model. Both models fit well with the simulation of soil N mineralization process in the coastal freshwater wetlands under a range of 30 to 40°C (R2 = 0.88–0.99, P<0.01). Our results indicated that an enhanced NH4 +-N release with increasing temperature and salinity deriving from the projected global warming could have profound effects on nutrient cycling in coastal wetland ecosystems. PMID:24733366

Time trends in minimum mortality temperatures in Castile-La Mancha (Central Spain): 1975-2003

NASA Astrophysics Data System (ADS)

Miron, Isidro J.; Criado-Alvarez, Juan José; Diaz, Julio; Linares, Cristina; Mayoral, Sheila; Montero, Juan Carlos

2008-03-01

The relationship between air temperature and human mortality is described as non-linear, with mortality tending to rise in response to increasingly hot or cold ambient temperatures from a given minimum mortality or optimal comfort temperature, which varies from some areas to others according to their climatic and socio-demographic characteristics. Changes in these characteristics within any specific region could modify this relationship. This study sought to examine the time trend in the maximum temperature of minimum organic-cause mortality in Castile-La Mancha, from 1975 to 2003. The analysis was performed by using daily series of maximum temperatures and organic-cause mortality rates grouped into three decades (1975-1984, 1985-1994, 1995-2003) to compare confidence intervals ( p < 0.05) obtained by estimating the 10-yearly mortality rates corresponding to the maximum temperatures of minimum mortality calculated for each decade. Temporal variations in the effects of cold and heat on mortality were ascertained by means of ARIMA models (Box-Jenkins) and cross-correlation functions (CCF) at seven lags. We observed a significant decrease in comfort temperature (from 34.2°C to 27.8°C) between the first two decades in the Province of Toledo, along with a growing number of significant lags in the summer CFF (1, 3 and 5, respectively). The fall in comfort temperature is attributable to the increase in the effects of heat on mortality, due, in all likelihood, to the percentage increase in the elderly population.

The effects of temperature on metabolic interaction between digestion and locomotion in juveniles of three cyprinid fish (Carassius auratus, Cyprinus carpio and Spinibarbus sinensis).

PubMed

Pang, Xu; Cao, Zhen-Dong; Fu, Shi-Jian

2011-07-01

To test whether the effects of temperature on the metabolic mode changed among different fish species, we investigated the specific dynamic action (SDA) and swimming performance of fasting and fed fish at 15 and 25°C in three juvenile Cyprinidae fish species: goldfish (Carassius auratus), common carp (Cyprinus carpio) and qingbo (Spinibarbus sinensis). Both taxon and temperature had significant effects on the resting oxygen consumption rate (M˙O(rest)), SDA and swimming performance (p<0.05). In addition, the effect of temperature differed significantly among the different species (interaction effect, p<0.05). Under the low temperature condition, digestion had no effect on either critical swimming speed (U(crit)) or the active MO(2) (MO(active)) for all fish species (additive metabolic mode). When the temperature was increased from 15 to 25°C, the metabolic scope (MS) for digestion increased approximately 182, 49 and 17%, and the MS for locomotion increased approximately 129, 58 and 138% in goldfish, common carp and qingbo, respectively. The total metabolic demands for both digestion and locomotion (i.e., the sum of digestive MS and locomotive MS) increased approximately 143, 56 and 112% in goldfish, common carp and qingbo, respectively. The total MS for both digestion and locomotion (the difference between MO(active) in fed fish and MO(rest) in fasting fish) increased approximately 106, 58 and 78% in goldfish, common carp and qingbo, respectively. Thus, the MS for locomotion in fed goldfish decreased due to the large increase in digestive function at the high temperature, and the U(crit) of fed goldfish decreased by 11% compared to that of fasting fish (p<0.05) (digestion-priory metabolic mode). The metabolic mode of qingbo changed to locomotion-priority mode, as illustrated by the large increase in locomotive MS in response to the increase in temperature. In the common carp, temperature had no effect on metabolic mode as illustrated by the parallel increases in cardio-respiratory capacity and metabolic capacity of digestive and locomotive organs. A discussion on the changes in metabolic mode in response to temperature and its possible relationship with the metabolic characteristics of a given fish species was also documented in this paper. Copyright © 2011 Elsevier Inc. All rights reserved.

Hydrothermal deformation of granular quartz sand

NASA Astrophysics Data System (ADS)

Karner, Stephen L.; Kronenberg, Andreas K.; Chester, Frederick M.; Chester, Judith S.; Hajash, Andrew

2008-05-01

Isotropic and triaxial compression experiments were performed on porous aggregates of St Peter quartz sand to explore the influence of temperature (to 225°C). During isotropic stressing, samples loaded at elevated temperature exhibit the same sigmoidal stress-strain curves and non-linear acoustic emission rates as have previously been observed from room temperature studies on sands, sandstones, and soils. However, results from our hydrothermal experiments show that the critical effective pressure (P*) associated with the onset of significant pore collapse and pervasive cataclastic flow is lower at increased temperature. Samples subjected to triaxial loading at elevated temperature show yield behavior resembling that observed from room temperature studies on granular rocks and soils. When considered in terms of distortional and mean stresses, the yield strength data for a given temperature define an elliptical envelope consistent with critical state and CAP models from soil mechanics. For the conditions we tested, triaxial yield data at low effective pressure are essentially temperature-insensitive whereas yield levels at high effective pressure are lowered as a function of elevated temperature. We interpret our yield data in a manner consistent with Arrhenius behavior expected for thermally assisted subcritical crack growth. Taken together, our results indicate that increased stresses and temperatures associated with subsurface burial will significantly alter the yield strength of deforming granular media in systematic and predictable ways.

Moderate Increase of Mean Daily Temperature Adversely Affects Fruit Set of Lycopersicon esculentum by Disrupting Specific Physiological Processes in Male Reproductive Development

PubMed Central

SATO, S.; KAMIYAMA, M.; IWATA, T.; MAKITA, N.; FURUKAWA, H.; IKEDA, H.

2006-01-01

• Background and Aims Global warming is gaining significance as a threat to natural and managed ecosystems since temperature is one of the major environmental factors affecting plant productivity. Hence, the effects of moderate temperature increase on the growth and development of the tomato plant (Lycopersicon esculentum) were investigated. • Methods Plants were grown at 32/26 °C as a moderately elevated temperature stress (METS) treatment or at 28/22 °C (day/night temperatures) as a control with natural light conditions. Vegetative growth and reproductive development as well as sugar content and metabolism, proline content and translocation in the androecium were investigated. • Key Results METS did not cause a significant change in biomass, the number of flowers, or the number of pollen grains produced, but there was a significant decrease in the number of fruit set, pollen viability and the number of pollen grains released. Glucose and fructose contents in the androecium (i.e. all stamens from one flower) were generally higher in the control than METS, but sucrose was higher in METS. Coincidently, the mRNA transcript abundance of acid invertase in the androecium was decreased by METS. Proline contents in the androecium were almost the same in the control and METS, while the mRNA transcript level of proline transporter 1, which expresses specifically at the surface of microspores, was significantly decreased by METS. • Conclusions The research indicated that failure of tomato fruit set under a moderately increased temperature above optimal is due to the disruption of sugar metabolism and proline translocation during the narrow window of male reproductive development. PMID:16497700

Thermotolerance and Heat-Shock Protein Gene Expression Patterns in Bemisia tabaci (Hemiptera: Aleyrodidae) Mediterranean in Relation to Developmental Stage.

PubMed

Jiang, Rui; Qi, Lan-Da; Du, Yu-Zhou; Li, Yuan-Xi

2017-10-01

Temperature plays an important role in the growth, development, and geographic distribution of insects. There is convincing evidence that heat-shock proteins (HSPs) play important roles in helping organisms adapt to thermal stress. To better understand the physiological and ecological influence of thermal stress on the different development stages of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Mediterranean species (MED), nymphs and adults were shocked with temperatures of 35, 38, and 41℃ for 1 and 2 h, respectively, and the survival rate, fecundity, and developmental duration were investigated in the laboratory. The expression levels of the hsp40, hsp70, and hsp90 genes were assessed using real-time PCR. The results indicate that the survival rates of the nymphs and adults decreased with increased temperature. A 2-h heat shock at 41℃ induced a significant reduction in fecundity in adults and an increase in developmental duration in young nymphs. Hsp90 showed higher temperature responses to thermal stress than hsp40 or hsp70. The expression levels of the hsps in the adults were significantly down-regulated by a 2-h heat shock at 41℃ compared with that by a 1-h treatment. A significant decrease in the expression levels of the hsps also occurred in the adults when the temperature increased from 38 to 41℃ for the 2-h treatment, whereas no significant decrease occurred in the nymphs. Compared with previous studies, we provide some evidence indicating that MED has the potential to adapt to a wider temperature range than the Middle East-Asia Minor 1 species. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Behavioural response of juvenile Chinook salmon Oncorhynchus tshawytscha during a sudden temperature increase and implications for survival

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

Bellgraph, Brian J.; McMichael, Geoffrey A.; Mueller, Robert P.

2010-01-01

The behaviours of juvenile Chinook salmon Oncorhynchus tshawytscha were evaluated during a temperature increase from 8.8 to 23.2°C, which was designed to simulate unique thermal conditions present in a hydroelectric reservoir. The percent of fish with an active swimming behaviour increased from 26 to 93 % and mean opercular beat rates increased from 76 to 159 beats per minute between basal and maximum temperatures. Fish equilibrium did not change significantly throughout the experiment and relatively little mortality (12 %) occurred. Thermal stress is likely incurred by juvenile salmon experiencing a temperature change of this magnitude; however, stress induced in thismore » study was primarily sublethal. Behavioural changes accompanying thermal stress (e.g., erratic swimming) may increase predation potential in the wild despite being sublethal during laboratory experiments.« less

Effect of artificial gravity on thermoregulation, respiratory metabolism and intermediary metabolism of animals

NASA Technical Reports Server (NTRS)

Oyama, J.

1973-01-01

Metabolic alterations in animals exposed to radial acceleration are reported. Temperatures in acutely stressed animals dropped profoundly in correlation with decreased food consumption. Repeated exposure of the acutely stressed animal caused a decrease in hypothermic response whereas deceleration or reduction of G load did not significantly change body temperatures. Adrenal corticosteroids affected significantly the animal's recovery rate. No changes occured in body temperature patterns of chronically centrifuged animals after full adaptation; their respiratory rate increased very significantly in terms of CO2 output as did their glucose uptake by muscle tissues and their insulin responsiveness or sensitivity.

First year growth in the lithodids Lithodes santolla and Paralomis granulosa reared at different temperatures

NASA Astrophysics Data System (ADS)

Calcagno, J. A.; Lovrich, G. A.; Thatje, S.; Nettelmann, U.; Anger, K.

2005-10-01

The southern king crab, Lithodes santolla Molina, and stone crab, Paralomis granulosa Jacquinot, inhabit the cold-temperate waters of southernmost South America (southern Chile and Argentina), where stocks of both species are endangered by overfishing. Recent investigations have shown that these crabs show life-cycle adaptations to scarcity of food and low temperatures prevailing in subantarctic regions, including complete lecithotrophy of all larval stages and prolonged periods of brooding and longevity. However, growth and development to maturity are slow under conditions of low temperatures, which may explain the particular vulnerability of subpolar lithodids to fisheries. In the present study, juvenile L. santolla and P. granulosa were individually reared in the laboratory at constant temperatures ranging from 3-15 °C, and rates of survival and development through successive instars were monitored throughout a period of about nine months from hatching. When the experiments were terminated, L. santolla had maximally reached juvenile instar IV (at 6 °C), V (9 °C), or VII (15 °C). In P. granulosa the maximum crab instar reached was II (at 3 °C), V (6 °C), V (9 °C), or VII (15 °C). The intermoult period decreased with increasing temperature, while it increased in successively later instars. In consequence, growth rate showed highly significant differences among temperatures (P<0.001). Growth-at-moult was highest at 9 °C. Rates of survival decreased significantly in juvenile P. granulosa with increasing temperature. Only at 15 °C in L. santolla, was a significantly enhanced mortality found compared with lower temperatures. Our results indicate that juvenile stages of L. santolla and P. granulosa are well adapted to 5-10°C, the range of temperatures typically prevailing in subantarctic marine environments. In spite of causing higher mortality rates, higher rearing temperatures (12-15 °C) should accelerate the rates of growth and maturation, which may be favourable for projects aiming at aquaculture or repopulation of overexploited king crab stocks.

Performance of large-bore tapered-roller bearings under combined radial and thrust load at shaft speeds to 15,000 rpm

NASA Technical Reports Server (NTRS)

Parker, R. J.; Signer, H. R.

1977-01-01

The performance of 120.65-mm bore tapered roller bearings was investigated at shaft speeds up to 15,000 rpm. Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rate, and lubricant inlet temperature. Lubricant was supplied by either jets or by a combination of holes through the cone directly to the cone-rib contact and jets at the roller small-end side. Cone-rib lubrication significantly improved high-speed tapered-roller bearing performance, yielding lower cone-face temperatures and lower power loss and allowing lower lubricant flow rates for a given speed condition. Bearing temperatures increased with increased shaft speed and decreased with increased lubricant flow rate. Bearing power loss increased with increased shaft speed and increased lubricant flow rate.

Influence of temperature fluctuations during cryopreservation on vital parameters, differentiation potential, and transgene expression of placental multipotent stromal cells.

PubMed

Pogozhykh, Denys; Pogozhykh, Olena; Prokopyuk, Volodymyr; Kuleshova, Larisa; Goltsev, Anatoliy; Blasczyk, Rainer; Mueller, Thomas

2017-03-11

Successful implementation of rapidly advancing regenerative medicine approaches has led to high demand for readily available cellular suspensions. In particular, multipotent stromal cells (MSCs) of placental origin have shown therapeutic efficiency in the treatment of numerous pathologies of varied etiology. Up to now, cryopreservation is the only effective way to preserve the viability and unique properties of such cells in the long term. However, practical biobanking is often associated with repeated temperature fluctuations or interruption of a cold chain due to various technical, transportation, and stocking events. While biochemical processes are expected to be suspended during cryopreservation, such temperature fluctuations may lead to accumulation of stress as well as to periodic release of water fractions in the samples, possibly leading to damage during long-term storage. In this study, we performed a comprehensive analysis of changes in cell survival, vital parameters, and differentiation potential, as well as transgene expression of placental MSCs after temperature fluctuations within the liquid nitrogen steam storage, mimicking long-term preservation in practical biobanking, transportation, and temporal storage. It was shown that viability and metabolic parameters of placental MSCs did not significantly differ after temperature fluctuations in the range from -196 °C to -100 °C in less than 20 cycles in comparison to constant temperature storage. However, increasing the temperature range to -80 °C as well as increasing the number of cycles leads to significant lowering of these parameters after thawing. The number of apoptotic changes increases depending on the number of cycles of temperature fluctuations. Besides, adhesive properties of the cells after thawing are significantly compromised in the samples subjected to temperature fluctuations during storage. Differentiation potential of placental MSCs was not compromised after cryopreservation with constant end temperatures or with temperature fluctuations. However, regulation of various genes after cryopreservation procedures significantly varies. Interestingly, transgene expression was not compromised in any of the studied samples. Alterations in structural and functional parameters of placental MSCs after long-term preservation should be considered in practical biobanking due to potential temperature fluctuations in samples. At the same time, differentiation potential and transgene expression are not compromised during studied storage conditions, while variation in gene regulation is observed.

Effects of Environmental Temperature and Dietary Fat Content on The Performance and Heat Production and Substrate Oxidation in Growing Pigs.

PubMed

Han, Rui; Jiang, Hailong; Che, Dongsheng; Bao, Nan; Xiang, Dong; Liu, Feifei; Yang, Huaming; Ban, Zhibin; Qin, Guixin

2017-01-01

This study aimed to evaluate the effect of temperature and dietary fat level on growth performance, heat production, nutrient oxidation and nitrogen balance in growing pigs. Thirty-two pigs (Duroc × Landrace × Large White) with initial weight of 25±1.91 kg were assigned to treatments in 2×4 factorial design. All pigs were fed with two isoenergetic and isoproteic diets of different fat levels (low fat level: 3.68% fat of dry matter (DM) and high fat level: 8.39% fat of DM) under four environmental temperatures (23, 18, 13 and 8 ºC). Heat production (HP) and nutrient oxidation were calculated from gas exchange via measurement with respiration chambers. The results showed that there was no interaction effect on growth performance by the temperature and dietary fat level. The average daily feed intake (ADFI) was lower (P < 0.001), the average daily gain (ADG) was higher (P < 0.001) and feed utilization was more efficient at 23 ºC than 13 and 8 ºC (P < 0.001). Dietary fat had no effect on growth performance and feed utilization at the four different temperatures. A significant interaction (P < 0.001) between temperature and dietary fat level on oxidation of carbohydrate (OXCHO) and fat (OXF) was observed. HP, OXF and OXCHO were significantly increased (P < 0.001) as environment temperatures decreased. Increasing dietary fat generated an increase in the OXF and decrease in the OXCHO (P < 0.001). No significant difference was observed in protein oxidation (OXP) of two factors. The intakes of nitrogen, nitrogen excretion in feces (FN) and urine (UN) by the pigs kept in 8 ºC environment were highest. Nitrogen digestibility decreased as environmental temperature decreased, with the most efficient gains obtained at 23 ºC. However, nitrogen retention was not influenced by environmental temperature. Dietary fat level did not affect nitrogen balance. No significant interaction between temperature and dietary fat level was observed for nitrogen balance. These results indicated that the rate of growth and nutrition utilization in pigs fed ad libitum are influenced by the environmental temperatures in which they are maintained, and the oxidation of nutrition utilization of the pig to different environmental temperatures is altered by the dietary fat supplementation. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Influence of time, temperature and coagulation on the measurement of C3, C3 split products and C4.

PubMed

Sinosich, M J; Teisner, B; Brandslund, I; Fisher, M; Grudzinskas, J G

1982-11-26

Quantitative and qualitative immunoelectrophoretic analyses of circulating C3, C3 split products and C4 were performed in matched EDTA plasma and serum obtained from 5 normal subjects and stored for up to 48 h at room temperature (18 degrees C-22 degrees C) and 4 degrees C. Fluctuations in apparent levels of C3 were greater in serum than plasma stored at room temperature, a fall in levels seen by 24 h being followed by a significant increase. By contrast, levels of C3 did not alter if stored at 4 degrees C. C4 levels in both EDTA plasma and serum remained unchanged for 24 h, a slight decrease being seen at 48 h. Levels of C4 remained constant if samples were stored at 4 degrees C. Crossed immunoelectrophoresis revealed a significant progressive decrease in C3 levels and a simultaneous increase in C3c occurring after 4 h in serum and 8 h in EDTA plasma, stored at room temperature. In studies conducted at 4 degrees C, similar but delayed fluctuations were seen. A progressive and significant increase in C3d levels was seen in both plasma and serum samples stored at room temperature, levels rising to 276% (plasma) and 308% (serum) of levels seen at zero time. At 4 degrees C marginal increases in C3d levels only were observed. These results suggest that in vitro degradation of C3 and C4 are readily facilitated by temperature, time and coagulation, and that conditions of collection and storage of samples must be optimized for the accurate definition of activation of the complement cascade.

Analysis of shade, temperature and hydrogen peroxide concentration during dental bleaching: in vitro study with the KTP and diode lasers.

PubMed

Fornaini, C; Lagori, G; Merigo, E; Meleti, M; Manfredi, M; Guidotti, R; Serraj, A; Vescovi, P

2013-01-01

Many dental bleaching techniques are now available, several of them using a laser source. However, the literature on the exact role of coherent light in the biochemical reaction of the whitening process is very discordant. The aims of this in vitro study were: (1) to compare two different laser sources, a KTP laser with a wavelength of 532 nm and a diode laser with a wavelength of 808 nm, during dental bleaching, and (2) to investigate the relationships among changes in gel temperature, tooth shade and hydrogen peroxide (HP) concentration during laser irradiation. Altogether, 116 bovine teeth were bleached using a 30% HP gel, some of them with gel only and others with gel plus one of the two lasers (532 or 808 nm) at two different powers (2 and 4 W). The KTP laser produced a significant shade variation with a minimal temperature increase. The diode laser led to a higher temperature increase with a greater reduction in HP concentration, but the change in shade was only statistically significant with a power of 4 W. At a power of 2 W, the KTP laser caused a greater change in shade than the diode laser. No significant correlations were found among temperature, HP concentration and shade variation. The KTP laser appears to provide better results with less dangerous thermal increases than the diode laser. This might call into question most of the literature affirming that the action of laser bleaching is by increasing the gel temperature and, consequently, the speed of the redox reaction. Further study is required to investigate the correlations between the parameters investigated and efficacy of the bleaching process.

Variations in the temperature sensitivity of spring leaf phenology from 1978 to 2014 in Mudanjiang, China

NASA Astrophysics Data System (ADS)

Dai, Junhu; Xu, Yunjia; Wang, Huanjiong; Alatalo, Juha; Tao, Zexing; Ge, Quansheng

2017-12-01

Continuous long-term temperature sensitivity (ST) of leaf unfolding date (LUD) and main impacting factors in spring in the period 1978-2014 for 40 plant species in Mudanjiang, Heilongjiang Province, Northeast China, were analyzed by using observation data from the China Phenological Observation Network (CPON), together with the corresponding meteorological data from the China Meteorological Data Service Center. Temperature sensitivities, slopes of the regression between LUD and mean temperature during the optimum preseason (OP), were analyzed using 15-year moving window to determine their temporal trends. Major factors impacting ST were then chosen and evaluated by applying a random sampling method. The results showed that LUD was sensitive to mean temperature in a defined period before phenophase onset for all plant species analyzed. Over the period 1978-2014, the mean ST of LUD for all plant species was - 3.2 ± 0.49 days °C-1. The moving window analysis revealed that 75% of species displayed increasing ST of LUD, with 55% showing significant increases (P < 0.05). ST for the other 25% exhibited a decreasing trend, with 17% showing significant decreases (P < 0.05). On average, ST increased by 16%, from - 2.8 ± 0.83 days °C-1 during 1980-1994 to - 3.30 ± 0.65 days °C-1 during 2000-2014. For species with later LUD and longer OP, ST tended to increase more, while species with earlier LUD and shorter OP tended to display a decreasing ST. The standard deviation of preseason temperature impacted the temporal variation in ST. Chilling conditions influenced ST for some species, but photoperiod limitation did not have significant or coherent effects on changes in ST.

Influence of elevated temperature and acid mine drainage on mortality of the crayfish Cambarus bartonii

USGS Publications Warehouse

Hartman, K.J.; Hom, C.D.; Mazik, P.M.

2010-01-01

Effects of elevated temperature and acid mine drainage (AMD) on crayfish mortality were investigated in the Stony River, Grant County, West Virginia. During summers 2003 and 2004, four-week in situ bioassays were performed along a thermal and AMD gradient with the native crayfish Cambarus bartonii. Crayfish mortality was analyzed in conjunction with temperature and AMD related variables (pH, specific conductivity). Mortality was significantly higher (48-88%) at sites with high temperatures during 2003 (max = 33.0??C), but no significant differences were observed in 2004 (max = 32.0??C). Temperatures were higher in 2003 than 2004 due to increased discharge from a cooling reservoir flowing into the river. Additionally, duration of high temperature was approximately four days in 2003 as compared with only one day in 2004. No significant relationship between acid mine drainage variables and crayfish mortality was apparent.

Increase in milk and body temperature of cows as a sign of embryo entry into the uterus.

PubMed

Gil, Z; Kural, J; Szarek, J; Wierzchoś, E

2001-09-01

The objective of the first stage of these studies was to investigate whether temperature increases in the milk and body of cows during the early period of pregnancy. We studied 94 pregnant and 116 nonpregnant cows, and the temperatures were measured daily beginning 24 days after insemination. In addition, progesterone levels in milk were measured twice (on Days 21 and 24 after insemination), and examinations per rectum were conducted to determine pregnancy. Data analysis showed that in almost 90% of the pregnant cows milk temperature increased by 0.64 degrees C some time between Days 5 and 12 after insemination. This increase in milk temperature was highly significant and corresponded with a 0.46 degrees C increase in body temperature. There was no increase in the milk or body temperature in nonpregnant cows. After discovering in the first stage that a high percentage of pregnant cows experienced both milk and body temperature increases, we focused our attention in the second stage of the study on the question of whether this increase in temperatures might be due to an immune response of the mother to the entry of the embryo into the uterus. In this stage we conducted three different experiments on another group of animals consisting of 309 cows and heifers. The experiments included analysis of progesterone, estradiol, cortisol and PGE2 levels in the blood serum of the cows and heifers; an estimation of the pyrogenic activity of PGE1, PGE2 and progesterone; and measurements of body temperature in the heifers before and after embryo transfer. The results of these experiments suggested that an increase in milk and body temperature could be an indicator of an immune response of the mother to the entry of the embryo into the uterus.

Meteorological variables and bacillary dysentery cases in Changsha City, China.

PubMed

Gao, Lu; Zhang, Ying; Ding, Guoyong; Liu, Qiyong; Zhou, Maigeng; Li, Xiujun; Jiang, Baofa

2014-04-01

This study aimed to investigate the association between meteorological-related risk factors and bacillary dysentery in a subtropical inland Chinese area: Changsha City. The cross-correlation analysis and the Autoregressive Integrated Moving Average with Exogenous Variables (ARIMAX) model were used to quantify the relationship between meteorological factors and the incidence of bacillary dysentery. Monthly mean temperature, mean relative humidity, mean air pressure, mean maximum temperature, and mean minimum temperature were significantly correlated with the number of bacillary dysentery cases with a 1-month lagged effect. The ARIMAX models suggested that a 1°C rise in mean temperature, mean maximum temperature, and mean minimum temperature might lead to 14.8%, 12.9%, and 15.5% increases in the incidence of bacillary dysentery disease, respectively. Temperature could be used as a forecast factor for the increase of bacillary dysentery in Changsha. More public health actions should be taken to prevent the increase of bacillary dysentery disease with consideration of local climate conditions, especially temperature.

Meteorological Variables and Bacillary Dysentery Cases in Changsha City, China

PubMed Central

Gao, Lu; Zhang, Ying; Ding, Guoyong; Liu, Qiyong; Zhou, Maigeng; Li, Xiujun; Jiang, Baofa

2014-01-01

This study aimed to investigate the association between meteorological-related risk factors and bacillary dysentery in a subtropical inland Chinese area: Changsha City. The cross-correlation analysis and the Autoregressive Integrated Moving Average with Exogenous Variables (ARIMAX) model were used to quantify the relationship between meteorological factors and the incidence of bacillary dysentery. Monthly mean temperature, mean relative humidity, mean air pressure, mean maximum temperature, and mean minimum temperature were significantly correlated with the number of bacillary dysentery cases with a 1-month lagged effect. The ARIMAX models suggested that a 1°C rise in mean temperature, mean maximum temperature, and mean minimum temperature might lead to 14.8%, 12.9%, and 15.5% increases in the incidence of bacillary dysentery disease, respectively. Temperature could be used as a forecast factor for the increase of bacillary dysentery in Changsha. More public health actions should be taken to prevent the increase of bacillary dysentery disease with consideration of local climate conditions, especially temperature. PMID:24591435

Effects of ambient temperature on mechanomyography of resting quadriceps muscle.

PubMed

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

2013-03-01

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

Organic geochemical investigations of the Dali Lake sediments in northern China: Implications for environment and climate changes of the last deglaciation in the East Asian summer monsoon margin

NASA Astrophysics Data System (ADS)

Fan, Jiawei; Xiao, Jule; Wen, Ruilin; Zhang, Shengrui; Wang, Xu; Cui, Linlin; Yamagata, Hideki

2017-06-01

Millennial-scale environment and climate changes in the East Asian summer monsoon margin during the last deglaciation are reconstructed by systematic studies on the characteristic of sedimentary organic matter from Dali Lake in northern China. Concurrent increases in the TOC and TN concentrations indicate increases in terrestrial organic matter and nutrient inputs to the lake and a development of terrestrial vegetation and phytoplankton productivity related to increases in regional temperature and precipitation. C/N ratios reflect changes in the proportions of terrestrial and aquatic organic matter. Decreases in both δ13Corg and δ15N values indicate increases in the isotopically lighter, terrestrial carbon and nitrogen inputs to the lake, due to increases in surface runoffs; while a sharp decrease in the δ15N value implies a significant weakening in the biological activities of nitrifying and amonifying bacteria, due to abrupt decrease in the water temperature. The geochemical data indicate that regional temperature and precipitation exhibited increasing trends from 15,000 to 12,350 cal yr BP; temperature decreased abruptly at 12,350 cal yr BP and then maintained a low level from 12,350 to 11,400 cal yr BP, precipitation decreased to a relatively low level from 12,350 to 11,400 cal yr BP; and both temperature and precipitation returned to increase after 11,400 cal yr BP. The climate change in the Dali Lake region during the last deglaciation corresponds, within age uncertainties, to the Bølling-Allerød (BA) warm phase and Younger Dryas (YD) cold reversal occurring over northern high latitudes. However, the gradual and mild increasing trends of regional temperature and precipitation during the BA warm period contrasts with the general cooling trend in northern high latitude temperature, implying a dominant influence from increases in the Northern Hemisphere summer insolation; while the slight decreases in regional precipitation relative to the rapid and significant decreases in northern high latitude temperature during the YD cold period may have resulted from local moisture recycling or from an insensitive response of hydrology and ecology to the regional precipitation change.

Temperature differentially regulates the two kisspeptin systems in the brain of zebrafish.

PubMed

Shahjahan, Md; Kitahashi, Takashi; Ogawa, Satoshi; Parhar, Ishwar S

2013-11-01

Kisspeptins encoded by the kiss1 and kiss2 genes play an important role in reproduction through the stimulation of gonadotropin-releasing hormone (GnRH) secretion by activating their receptors (KissR1 EU047918 and KissR2 EU047917). To understand the mechanism through which temperature affects reproduction, we examined kiss1 and kiss2 and their respective receptor (kissr1 and kissr2) gene expression in the brain of male zebrafish exposed to a low temperature (15°C), normal temperature (27°C), and high temperature (35°C) for 7-days. kiss1 mRNA levels in the brain were significantly increased (2.9-fold) in the low temperature compared to the control (27°C), while no noticeable change was observed in the high temperature conditions. Similarly, kissr1 mRNA levels were significantly increased (1.5-2.2-folds) in the low temperature conditions in the habenula, the nucleus of the medial longitudinal fascicle, oculomotor nucleus, and the interpeduncular nucleus. kiss2 mRNA levels were significantly decreased (0.5-fold) in the low and high temperature conditions, concomitant with kissr2 mRNA levels (0.5-fold) in the caudal zone of the periventricular hypothalamus and the posterior tuberal nucleus. gnrh3 but not gnrh2 mRNA levels were also decreased (0.5-fold) in the low and high temperature conditions. These findings suggest that while the kiss1/kissr1 system is sensitive to low temperature, the kiss2/kissr2 system is sensitive to both extremes of temperature, which leads to failure in reproduction. Copyright © 2013. Published by Elsevier Inc.

Increasing trend in the average temperature in Finland, 1847-2012

NASA Astrophysics Data System (ADS)

Mikkonen, Santtu; Laine, Marko; Mäkelä, Hanna M.; Gregow, Hilppa; Tuomenvirta, Heikki; Lahtinen, Matti; Laaksonen, Ari

2014-05-01

The global average temperature has increased by about 0.8 ° C since the mid-19th century. It has been shown that this increase is statistically significant and that it can, for the most part, be attributed to human-induced climate change (IPCC 2007). A temperature increase is obvious also in regional and local temperatures in many parts of the world. However, compared with the global average temperature, the regional and local temperatures exhibit higher levels of noise, which has largely been removed from the global temperature due to the higher level of averaging. Because Finland is located in northern latitudes, it is subject to the polar amplification of climate change-induced warming, which is due to the enhanced melting of snow and ice and other feedback mechanisms. Therefore, warming in Finland is expected to be approximately 50% higher than the global average. Conversely, the location of Finland between the Atlantic Ocean and continental Eurasia causes the weather to be very variable, and thus the temperature signal is rather noisy. The change in mean temperature in Finland was investigated with Dynamic Linear Models (DLM) in order to define the sign and the magnitude of the trend in the temperature time series within the last 165 years. The data consisted of gridded monthly mean temperatures. The grid has a 10 km spatial resolution, and it was created by interpolating a homogenized temperature series measured at Finnish weather stations. Seasonal variation in temperature and the autocorrelation structure of the time series were taken account in the DLM models. We found that the Finnish temperature time series exhibits a statistically significant increasing trend, which is consistent with human-induced global warming. The mean temperature has risen clearly over 2° C in the years 1847-2012, which amounts to 0.16 ° C/decade. The warming rate before 1940's was close to the linear trend for the whole period, whereas the temperature change in the mid-20th century was negligible. However, the warming after the late 1960s has been remarkably fast. The model indicates that within the last 40 years the rate of change has been as high as 0.30 ° C/decade. The increase in temperature has been highest in spring and in late autumn but the change in summer months has not been so evident. The observed warming is somewhat higher than the global trend, which confirms the assumption that warming is stronger in higher latitudes.

Comparison of heat dissipation response between Malaysian and Japanese males during exercise in humid heat stress.

PubMed

Wakabayashi, Hitoshi; Wijayanto, Titis; Lee, Joo-Young; Hashiguchi, Nobuko; Saat, Mohamed; Tochihara, Yutaka

2011-07-01

This study investigated the differences in heat dissipation response to intense heat stress during exercise in hot and humid environments between tropical and temperate indigenes with matched physical characteristics. Ten Japanese (JP) and ten Malaysian (MY) males participated in this study. Subjects performed exercise for 60 min at 55% peak oxygen uptake in 32°C air with 70% relative humidity, followed by 30 min recovery. The increase in rectal temperature (T(re)) was smaller in MY during exercise compared to JP. The local sweat rate and total body mass loss were similar in both groups. Both skin blood flow and mean skin temperature was lower in MY compared to JP. A significantly greater increase in hand skin temperature was observed in MY during exercise, which is attributable to heat loss due to the greater surface area to mass ratio and large number of arteriovenous anastomoses. Also, the smaller increase in T(re) in MY may be explained by the presence of a significantly greater core-skin temperature gradient in MY than JP. The thermal gradient is also a major factor in increasing the convective heat transfer from core to skin as well as skin blood flow. It is concluded that the greater core-skin temperature gradient observed in MY is responsible for the smaller increase in T(re).

Hydrologic and climatic changes in three small watersheds after timber harvest.

Treesearch

W.B. Fowler; J.D. Helvey; E.N. Felix

1987-01-01

No significant increases in annual water yield were shown for three small watersheds in northeastern Oregon after shelterwood cutting (30-percent canopy removal, 50-percent basal area removal) and clearcutting. Average maximum air temperature increased after harvest and average minimum air temperature decreased by up to 2.6 °C. Both maximum and minimum water...

Physiological and subjective responses in the elderly when using floor heating and air conditioning systems.

PubMed

Hashiguchi, Nobuko; Tochihara, Yutaka; Ohnaka, Tadakatsu; Tsuchida, Chiaki; Otsuki, Tamio

2004-11-01

The purpose of this study was to investigate the effects of a floor heating and air conditioning system on thermal responses of the elderly. Eight elderly men and eight university students sat for 90 minutes in a chair under the following 3 conditions: air conditioning system (A), floor heating system (F) and no heating system (C). The air temperature of sitting head height for condition A was 25 degrees C, and the maximum difference in vertical air temperature was 4 degrees C. The air and floor temperature for condition F were 21 and 29 degrees C, respectively. The air temperature for condition C was 15 degrees C. There were no significant differences in rectal temperature and mean skin temperature between condition A and F. Systolic blood pressure of the elderly men in condition C significantly increased compared to those in condition A and F. No significant differences in systolic blood pressure between condition A and F were found. The percentage of subjects who felt comfortable under condition F was higher than that of those under condition A in both age groups, though the differences between condition F and A was not significant. Relationships between thermal comfort and peripheral (e.g., instep, calf, hand) skin temperature, and the relationship between thermal comfort and leg thermal sensation were significant for both age groups. However, the back and chest skin temperature and back thermal sensation for the elderly, in contrast to that for the young, was not significantly related to thermal comfort. These findings suggested that thermal responses and physiological strain using the floor heating system did not significantly differ from that using the air conditioning system, regardless of the subject age and despite the fact that the air temperature with the floor heating system was lower. An increase in BP for elderly was observed under the condition in which the air temperature was 15 degrees C, and it was suggested that it was necessary for the elderly people to heat the room somehow in winter. Moreover, it is particularly important for elderly people to avoid a decrease in peripheral skin temperature, and maintain awareness of the warmth of peripheral areas, such as the leg, in order to ensure thermal comfort.

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

PubMed

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

2016-07-12

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

Attenuated thermoregulatory responses with increased plasma osmolality in obese subjects during two seasons

NASA Astrophysics Data System (ADS)

Kanikowska, Dominika; Sato, Maki; Sugenoya, Junichi; Shimizu, Yuuki; Nishimura, Naoki; Inukai, Yoko; Iwase, Satoshi

2013-09-01

Obese subjects may be more vulnerable to injury from heat stress, and appear to be less efficient at thermoregulation. Sweat rate, tympanic temperature and osmolality in obese subjects were investigated in Japan during two seasons. The purpose of this study was to examine the relationship between obesity, thermoregulatory response and season. Five obese (BMI, 32.0 ± 4.9 kg/m2) and five non-obese (BMI, 23.2 ± 2.9 kg/m2) men participated in this experiment at latitude 35°10' N and longitude 136°57.9'E. The average atmospheric temperature was 29.1 ± 1.0 °C in summer and 3.3 ± 1.4 °C in winter. Tympanic temperature and sweat rate were measured during leg water immersion at 42 °C for 30 min. Blood samples were analyzed for plasma osmolality. The relationship between tympanic temperature and sweat rate decreased significantly in obese compared to in non-obese subjects in both seasons, there being a lowered sweat rate for any core temperature in obese subjects. Plasma osmolality was significantly higher in obese than in non-obese subjects in both seasons. Thermal sensation increased significantly in non-obese than in obese in winter but not in summer. Our data show that thermoregulatory responses are attenuated in obese subjects compared with controls, suggesting that obese people are at increased risk of heat-related illnesses.

Effect of Continuous Propofol Infusion in Rat on Tau Phosphorylation with or without Temperature Control.

PubMed

Huang, Chunxia; Ng, Olivia Tsz-Wa; Ho, Yuen-Shan; Irwin, Michael Garnet; Chang, Raymond Chuen-Chung; Wong, Gordon Tin-Chun

2016-01-01

Several studies suggest a relationship between anesthesia-induced tau hyperphosphorylation and the development of postoperative cognitive dysfunction. This study further characterized the effects of continuous propofol infusion on tau protein phosphorylation in rats, with or without temperature control. Propofol was administered intravenously to 8-10-week-old male Sprague-Dawley rats and infused to the loss of the righting reflex for 2 h continuously. Proteins from cortex and hippocampus were examined by western blot and immunohistochemistry. Rectal temperature was significantly decreased during propofol infusion. Propofol with hypothermia significantly increased phosphorylation of tau at AT8, AT180, Thr205, and Ser199 in cortex and hippocampus except Ser396. With temperature maintenance, propofol still induced significant elevation of AT8, Thr205, and Ser199 in cortex and hippocampus; however, increase of AT180 and Ser396 was only found in hippocampus and cortex, respectively. Differential effects of propofol with or without hypothermia on multiple tau related kinases, such as Akt/GSK3β, MAPK pathways, or phosphatase (PP2A), were demonstrated in region-specific manner. These findings indicated that propofol increased tau phosphorylation under both normothermic and hypothermic conditions, and temperature control could partially attenuate the hyperphosphorylation of tau. Further studies are warranted to determine the long-term impact of propofol on the tau pathology and cognitive functions.

Out of the frying pan into the air—emersion behaviour and evaporative heat loss in an amphibious mangrove fish (Kryptolebias marmoratus)

PubMed Central

Gibson, Daniel J.; Sylvester, Emma V. A.; Turko, Andy J.; Tattersall, Glenn J.; Wright, Patricia A.

2015-01-01

Amphibious fishes often emerse (leave water) when faced with unfavourable water conditions. How amphibious fishes cope with the risks of rising water temperatures may depend, in part, on the plasticity of behavioural mechanisms such as emersion thresholds. We hypothesized that the emersion threshold is reversibly plastic and thus dependent on recent acclimation history rather than on conditions during early development. Kryptolebias marmoratus were reared for 1 year at 25 or 30°C and acclimated as adults (one week) to either 25 or 30°C before exposure to an acute increase in water temperature. The emersion threshold temperature and acute thermal tolerance were significantly increased in adult fish acclimated to 30°C, but rearing temperature had no significant effect. Using a thermal imaging camera, we also showed that emersed fish in a low humidity aerial environment (30°C) lost significantly more heat (3.3°C min−1) than those in a high humidity environment (1.6°C min−1). In the field, mean relative humidity was 84%. These results provide evidence of behavioural avoidance of high temperatures and the first quantification of evaporative cooling in an amphibious fish. Furthermore, the avoidance response was reversibly plastic, flexibility that may be important for tropical amphibious fishes under increasing pressures from climatic change. PMID:26490418

Out of the frying pan into the air--emersion behaviour and evaporative heat loss in an amphibious mangrove fish (Kryptolebias marmoratus).

PubMed

Gibson, Daniel J; Sylvester, Emma V A; Turko, Andy J; Tattersall, Glenn J; Wright, Patricia A

2015-10-01

Amphibious fishes often emerse (leave water) when faced with unfavourable water conditions. How amphibious fishes cope with the risks of rising water temperatures may depend, in part, on the plasticity of behavioural mechanisms such as emersion thresholds. We hypothesized that the emersion threshold is reversibly plastic and thus dependent on recent acclimation history rather than on conditions during early development. Kryptolebias marmoratus were reared for 1 year at 25 or 30°C and acclimated as adults (one week) to either 25 or 30°C before exposure to an acute increase in water temperature. The emersion threshold temperature and acute thermal tolerance were significantly increased in adult fish acclimated to 30°C, but rearing temperature had no significant effect. Using a thermal imaging camera, we also showed that emersed fish in a low humidity aerial environment (30°C) lost significantly more heat (3.3°C min(-1)) than those in a high humidity environment (1.6°C min(-1)). In the field, mean relative humidity was 84%. These results provide evidence of behavioural avoidance of high temperatures and the first quantification of evaporative cooling in an amphibious fish. Furthermore, the avoidance response was reversibly plastic, flexibility that may be important for tropical amphibious fishes under increasing pressures from climatic change. © 2015 The Author(s).

Seasonality in mortality and its relationship to temperature among the older population in Hanoi, Vietnam.

PubMed

Xuan, Le Thi Thanh; Egondi, Thaddaeus; Ngoan, Le Tran; Toan, Do Thi Thanh; Huong, Le Thi

2014-01-01

Several studies have established a relationship between temperature and mortality. In particular, older populations have been shown to be vulnerable to temperature effects. However, little information exists on the temperature-mortality relationship in Vietnam. This article aims to examine the monthly temperature-mortality relationship among older people in Hanoi, Vietnam, over the period between 2005 and 2010, and estimate seasonal patterns in mortality. We employed Generalized Additive Models, including smooth functions, to model the temperature-mortality relationships. A quasi-Poisson distribution was used to model overdispersion of death counts. Temporal trends, seasonality, and population size were adjusted for while estimating changes in monthly mortality over the study period. A cold month was defined as a month with a mean temperature below 19°C. This study found that the high peak of mortality coincided with low temperatures in the month of February 2008, during which the mean temperature was the lowest in the whole study period. There was a significant relationship between mean monthly temperature and mortality among the older people (p<0.01). Overall, there was a significant decrease in the number of deaths in the year 2009 during the study period. There was a 21% increase in the number of deaths during the cold season compared to the warm season. The increase in mortality during the cold period was higher among females compared to males (female: IRR [incidence relative risk] =1.23; male: IRR=1.18). Cold temperatures substantially increased mortality among the older population in Hanoi, Vietnam, and there were gender differences. Necessary preventive measures are required to mitigate temperature effects with greater attention to vulnerable groups.

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

PubMed

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

2010-01-01

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

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.

Temperature-dependent optical constants of highly transparent solids determined by the combined double optical pathlength transmission-ellipsometry method.

PubMed

Li, X C; Wang, C C; Zhao, J M; Liu, L H

2018-02-10

The optical constants of five highly transparent substrates (polycrystalline BaF 2 , CaF 2 , MgF 2 , ZnSe, and ZnS) were experimentally determined based on a combined technique using both the double optical pathlength transmission method and the ellipsometry method within temperature range 20°C-350°C in the ultraviolet-infrared region (0.2-20 μm). The results show that the refractive index spectra of polycrystalline BaF 2 , CaF 2 , and MgF 2 are similar, but differ from that of polycrystalline ZnSe and ZnS. The thermo-optic coefficient of these highly transparent substrates increases with increasing temperature. The absorption indices show a significant temperature-dependent behavior, which increases with increasing temperature from 20°C to 350°C over the transparent region. For the sake of application, the fitted formulas of the refractive index of the five highly transparent substrates as a function of wavelength and temperature are presented.

Browning of Adirondack, NY Lakes: Rates and Effects

NASA Astrophysics Data System (ADS)

Driscoll, C. T.; Mota, Y.; Fakhraei, H.; Todorova, S.; Leach, T.; Rose, K. C.; O'Donnell, S.

2017-12-01

Browning, or increases in the concentrations of dissolved organic matter (DOM), is an intriguing recent phenomenon occurring in northern freshwaters. It is hypothesized that browning is a watershed response to decreases in acid deposition, although changing in climate may also contribute. The Adirondack region of NY is experiencing marked increases in lake concentrations of dissolved organic carbon (DOC), with 29 out of 48 lakes in the Adirondack Long-Term Monitoring (ALTM) program showing significant increases and two exhibiting decreases since 1992. Increases in DOC is altering the acid base status of Adirondack lakes largely due increases in DOM with strongly acidic functional groups. DOM mobilization limits increases in acid neutralizing capacity that can be achieved in recovery of surface waters from acid deposition. A subset of ALTM lakes also appear to be experiencing changes in their physical characteristics during the summer stratification period, consistent with increases in DOM and browning. Of 28 lakes monitored for water column profiles since 1994: 8 are showing declines in thermocline depth (5 significant, p<0.05); all are exhibiting increases in epilimnetic temperature (9 significant); 26 are experiencing increases in the difference between epilimnetic and hypolimnetic temperatures (6 significant); and 17 are experiencing decreases in hypolimnetic dissolved oxygen concentrations (6 significant decreases, 1 increase). These changes may be a manifestation of increases in the attenuation of light associated with increases in DOM, increasing the intensity and duration of thermal stratification.

Observed changes of temperature extremes during 1960-2005 in China: natural or human-induced variations?

NASA Astrophysics Data System (ADS)

Zhang, Qiang; Li, Jianfeng; David Chen, Yongqin; Chen, Xiaohong

2011-12-01

The purpose of this study was to statistically examine changes of surface air temperature in time and space and to analyze two factors potentially influencing air temperature changes in China, i.e., urbanization and net solar radiation. Trends within the temperature series were detected by using Mann-Kendall trend test technique. The scientific problem this study expected to address was that what could be the role of human activities in the changes of temperature extremes. Other influencing factors such as net solar radiation were also discussed. The results of this study indicated that: (1) increasing temperature was observed mainly in the northeast and northwest China; (2) different behaviors were identified in the changes of maximum and minimum temperature respectively. Maximum temperature seemed to be more influenced by urbanization, which could be due to increasing urban albedo, aerosol, and air pollutions in the urbanized areas. Minimum temperature was subject to influences of variations of net solar radiation; (3) not significant increasing and even decreasing temperature extremes in the Yangtze River basin and the regions south to the Yangtze River basin could be the consequences of higher relative humidity as a result of increasing precipitation; (4) the entire China was dominated by increasing minimum temperature. Thus, we can say that the warming process of China was reflected mainly by increasing minimum temperature. In addition, consistently increasing temperature was found in the upper reaches of the Yellow River basin, the Yangtze River basin, which have the potential to enhance the melting of permafrost in these areas. This may trigger new ecological problems and raise new challenges for the river basin scale water resource management.

Diurnal temperature fluctuation effects on potatoes grown with 12 hr photoperiods

NASA Technical Reports Server (NTRS)

Bennett, S. M.; Tibbitts, T. W.; Cao, W.

1991-01-01

This study was designed to characterize the growth responses of potato (Solanum tuberosum L.) to diurnal temperature fluctuations. Potato plants of two cultivars, Norland and Denali, were grown for 90 days under 12 hr photoperiod in walk-in growth rooms at the University of Wisconsin Biotron. The alternating temperature was 22 C light/14 C dark and compared to a constant 18 C as control. At all temperature regimes vapor pressure deficit was maintained at 0.62 kPa (70% relative humidity [correction of humdidity] at 18 C). Plant height, plant dry weight, tuber dry weight, and harvest index were overall greater under the warm light/cool dark alternating temperatures than under the constant temperature. The differences between temperature treatments were greater for Denali than for Norland. Alternating temperatures increased Denali tuber weights by 25%, but no significant increase was found with Norland. Also the total plant weight was increased over 20% with Denali, but increased with Norland in only one of the two replications of the experiment. This study documents that alternating temperatures are a benefit to some cultivars but may not be of benefit to all cultivars.

The Effect of Cushion Properties on Skin Temperature and Humidity at the Body-Support Interface.

PubMed

Hsu, Tzu-Wen; Yang, Shu-Yu; Liu, Jung-Tai; Pan, Cheng-Tang; Yang, Yu-Sheng

2016-09-29

To explore the effects of various cushions on skin temperature and moisture at the body-seat interface during a 2-h period of continuous sitting. Seventy-eight participants were randomly assigned to sit on one of the three types of wheelchair cushion for unrelieved sitting over 2 h. Skin temperature and relative humidity (RH) were measured under the subjects' ischial tuberosities and thighs bilaterally with digital temperature and humidity sensors. Data were collected before sitting and at 15-min intervals thereafter. Participants sitting on foam-fluid hybrid cushions showed significantly lower skin temperatures than those sitting on air-filled and foam cushions (p < 0.05), but RH did not differ significantly among the cushions (p = 0.97). The three cushions produced a similar increasing trend in RH over time and RH reached a plateau during the 2-h sitting period. In order to select the appropriate wheelchair cushion, the microclimate (heat and moisture control) between the body-seat interface should be considered as well as pressure distribution. In comparison with foam-fluid hybrid cushions, the air-filled rubber and foam cushions tended to increase skin temperature by several degrees after prolonged sitting. However, cushion materials did not have significant differences in moisture accumulations.

The effect of cushion properties on skin temperature and humidity at the body-support interface.

PubMed

Hsu, Tzu-Wen; Yang, Shu-Yu; Liu, Jung-Tai; Pan, Cheng-Tang; Yang, Yu-Sheng

2016-09-29

The purpose of this study is to explore the effects of various cushions on skin temperature and moisture at the body-seat interface during a 2-hour period of continuous sitting. Seventy-eight participants were randomly assigned to sit on one of the three types of wheelchair cushions for unrelieved sitting for over 2 hours. Skin temperature and relative humidity (RH) were measured under the subjects' ischial tuberosities and thighs bilaterally with digital temperature and humidity sensors. Data were collected before sitting and at 15-minute intervals thereafter. Participants sitting on foam-fluid hybrid cushions showed significantly lower skin temperatures than those sitting on air-filled and foam cushions (p < 0.05), but RH did not differ significantly among the cushions (p = 0.97). The three cushions produced a similar increasing trend in RH over time and RH reached a plateau during the 2-hour sitting period. To select the appropriate wheelchair cushion, the microclimate (heat and moisture control) between the body-seat interface should be considered as well as pressure distribution. In comparison with foam-fluid hybrid cushions, the air-filled rubber and foam cushions tended to increase skin temperature by several degrees after prolonged sitting. However, cushion materials did not have significant differences in moisture accumulations.

Effect of temperature on the standard metabolic rates of juvenile and adult Exopalaemon carinicauda

NASA Astrophysics Data System (ADS)

Zhang, Chengsong; Li, Fuhua; Xiang, Jianhai

2015-03-01

Ridgetail white prawn ( Exopalaemon carinicauda) are of significant economic importance in China where they are widely cultured. However, there is little information on the basic biology of this species. We evaluated the effect of temperature (16, 19, 22, 25, 28, 31, and 34°C) on the standard metabolic rates (SMRs) of juvenile and adult E. carinicauda in the laboratory under static conditions. The oxygen consumption rate (OCR), ammonia-N excretion rate (AER), and atomic ratio of oxygen consumed to nitrogen consumed (O:N ratio) of juvenile and adult E. carinicauda were significantly influenced by temperature ( P < 0.05). Both the OCR and AER of juveniles increased significantly with increasing temperature from 16 to 34°C, but the maximum OCR for adults was at 31°C. Juvenile shrimp exhibited a higher OCR than the adults from 19 to 34°C. There was no significant difference between the AERs of the two life-stages from 16 to 31°C ( P >0.05). The O:N ratio in juveniles was significantly higher than that in the adults over the entire temperature range ( P <0.05). The temperature coefficient ( Q 10) of OCR and AER ranged from 5.03 to 0.86 and 6.30 to 0.85 for the adults, respectively, and from 6.09-1.03 and 3.66-1.80 for the juveniles, respectively. The optimal temperature range for growth of the juvenile and adult shrimp was from 28 to 31°C, based on Q 10 and SMR values. Results from the present study may be used to guide pond culture production of E. carinicauda.

Effects of living at two ambient temperatures on 24-h blood pressure and neuroendocrine function among obese and non-obese humans: a pilot study

NASA Astrophysics Data System (ADS)

Kanikowska, Dominika; Sato, Maki; Iwase, Satoshi; Shimizu, Yuuki; Nishimura, Naoki; Inukai, Yoko; Sugenoya, Junichi

2013-05-01

The effects of environmental temperature on blood pressure and hormones in obese subjects in Japan were compared in two seasons: summer vs winter. Five obese (BMI, 32 ± 5 kg/m2) and five non-obese (BMI, 23 ±3 kg/m2) men participated in this experiment at latitude 35°10' N and longitude 136°57.9' E. The average environmental temperature was 29 ± 1 °C in summer and 3 ± 1 °C in winter. Blood samples were analyzed for leptin, ghrelin, catecholamines, thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), total cholesterol, triglycerides, insulin and glucose. Blood pressure was measured over the course of 24 h in summer and winter. A Japanese version of the Profile of Mood States (POMS) questionnaire was also administered each season. Systolic and diastolic blood pressures in obese men were significantly higher in winter (lower environmental temperatures) than in summer (higher environmental temperatures). Noradrenaline and dopamine concentrations were also significantly higher at lower environmental temperatures in obese subjects, but ghrelin, TSH, fT3, fT4, insulin and glucose were not significantly different in summer and winter between obese and non-obese subjects. Leptin, total cholesterol and triglyceride concentrations were significantly higher in winter in obese than non-obese men. Results from the POMS questionnaire showed a significant rise in Confusion at lower environmental temperatures (winter) in obese subjects. In this pilot study, increased blood pressure may have been due to increased secretion of noradrenaline in obese men in winter, and the results suggest that blood pressure control in obese men is particularly important in winter.

The effect of temperature on the respiration and metabolism of the African burrowing scorpion (Opistophthalmus latimanus).

PubMed

van Aardt, Willie J; le Roux, Jacobus M; Lindeque, Jeremie Z; Mason, Shayne; Louw, Roan

2016-12-01

It is well known that scorpions are highly adapted to thermal temperatures. However, little is known of the metabolic and respiration adaptations caused by temperature fluctuations in these animals. Therefore we used the African burrowing scorpion Opistophthalmus latimanus to measure the effect of temperature on its metabolism and respiration. Radioactive d-glucose was injected into the ventral sinus of the circulatory system and metabolites of d-glucose were determined after six hour incubation at four temperatures (7, 17, 25 and 37°C). The oxygen consumption rate (ṀO 2 ) and carbon dioxide production rate (ṀCO 2 ) were measured simultaneously at 17, 25 and 37°C. The metabolomics investigation included LC-MS, GC-MS and NMR analytical platforms. The average radioactivity recovered after the carbon-14 d-glucose injection, glycogen precipitation and column fractionation at the four temperatures was between 92.4% and 95.0%. Strong acids, CO 2 and neutral compounds all increased with temperature, while glycogen and neutral sugars decreased as the temperature increased. Weak acids initially increased with temperature, then decreased again as the temperature was increased to 37°C. Respiration also gradually increased as the temperature was increased. Metabolomics identified 23 metabolites that were significantly influenced by temperature. Pathway analysis of these metabolites indicated numerous metabolic pathways that were affected by temperature, clearly demonstrating that the scorpion uses proteins, lipids and carbohydrates at higher temperatures to generate energy. However, protein catabolism seems to be the main source of energy at higher temperatures in these animals, although this needs to be confirmed in a more targeted metabolomics study. Copyright © 2016 Elsevier Inc. All rights reserved.

Changes in Temperature Sensitivity and Activation Energy of Soil Organic Matter Decomposition in Different Qinghai-Tibet Plateau Grasslands.

PubMed

Li, Jie; He, Nianpeng; Wei, Xuehong; Gao, Yang; Zuo, Yao

2015-01-01

Qinghai-Tibet Plateau grasslands are unique geographical regions and store substantial soil organic matter (SOM) in the soil surface, which make them very sensitive to global climate change. Here, we focused on three main grassland types (alpine meadow, steppe, and desert) and conducted a soil incubation experiment at five different temperatures (5, 10, 15, 20, and 25°C) to investigate SOM decomposition rates (R), temperature sensitivity (Q10), and activation energy (Ea). The results showed that grassland type and incubation temperature had significant impact on R (P < 0.001), and the values of R were exponential correlated with incubation temperature in three alpine grasslands. At the same temperature, R was in the following order: alpine meadow > alpinesteppe > alpine desert. The Q10 values differed significantly among different grasslands, and the overall trends were as follows: alpine meadow (1.56 ± 0.09) < alpine steppe (1.88 ± 0.23) < alpine desert (2.39 ± 0.32). Moreover, the Ea values differed significantly across different grassland types (P < 0.001) and increased with increasing incubation time. The exponential negative correlations between Ea and R at 20°C across all grassland types (all Ps < 0.001) indicated that the substrate-quality temperature hypothesis is applicable to the alpine grasslands. Our findings provide new insights for understanding the responses of SOM decomposition and storage to warming scenarios in this Plateau.

Moderating Effects of Weather-Related Factors on a Physical Activity Intervention.

PubMed

Welch, Whitney A; Spring, Bonnie; Phillips, Siobhan M; Siddique, Juned

2018-05-01

The purpose of this study is to identify whether weather-related factors moderate the effect of a physical activity (PA) intervention. Participants (N=204, 77% female, mean age 33 [SD=11] years, mean BMI 28.2 [SD=7.1]) from the Make Better Choices 1 trial, enrolled April 2005 to April 2008, were randomized to one of two treatment conditions: (1) increase moderate to vigorous physical activity (MVPA) treatment group, or (2) decrease sedentary behavior control group. Participants wore an accelerometer for 5 weeks: a 2-week baseline assessment followed by a 3-week intervention. Accelerometer data were used to estimate minutes/day of MVPA. Average daily temperature, day length, and precipitation were obtained from the National Climatic Data Center and combined with the accelerometer data. Linear mixed effects models were used to determine whether these weather-related factors moderated the effect of the intervention on MVPA. Separate models were fit for season, daily average temperature, and day length. There was a significant moderating effect of season on MVPA such that the PA intervention, as compared with control, increased MVPA 10.4 minutes more in the summer than in the winter (95% CI=1.1, 19.6, p=0.029). There was a significant moderating effect of daily temperature such that every 10°F increase in temperature was associated with an additional 1.5 minutes/day increase in the difference in MVPA increase between the two intervention conditions (95% CI=0.1, 2.9, p=0.015). There was a significant moderating effect of day length such that every additional hour of daylight was associated with a 2.23-minute increase in the PA intervention's impact on increasing MVPA (95% CI=0.8, 3.7, p=0.002). Day length and temperature had a significant moderating effect on change in MVPA during a PA intervention such that the intervention was less effective on colder days and on shorter days, independently. These results suggest that strategies to overcome environmental barriers should be considered when designing PA interventions for adults. Copyright © 2018 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Air temperature exposure and outdoor occupational injuries: a significant cold effect in Central Italy.

PubMed

Morabito, Marco; Iannuccilli, Maurizio; Crisci, Alfonso; Capecchi, Valerio; Baldasseroni, Alberto; Orlandini, Simone; Gensini, Gian Franco

2014-10-01

To investigate the short-term effect of air temperature on outdoor occupational injuries (out_OI) in Central Italy, also by taking different geographical factors and employment sectors of workers into account. Out_OI for all of Tuscany (Central Italy), from 2003 to 2010 (n=162,399), were provided by the National Institute of Insurance for Occupational Illness and Injury. Representative daily meteorological data of the geographical area under study were obtained from the European Reanalysis-interim climatological reanalysis archive. Relationships between short-term changes in air temperature and out_OI were studied through Generalised Additive Models. The exposure-response curves of out_OI and short-term changes in air temperature generally showed significant out_OI increases when cold conditions occurred. The air temperature breakpoint corresponded to the 10th centile (-0.8°C) of the air temperature time series used in this study: a 1°C decrease in temperature below the 10th centile corresponded to a 2.3% (CI 1.3% to 3.3%) increase of out_OI throughout all of Tuscany. The cold effect was strongest in plain areas, especially when out_OI occurred in vehicles other than cars. No relationships of injuries with temperature extremes were observed in workers who generally spend half or most of their time outdoors, such as construction, land and forestry workers. However, these latter outdoor workers showed significant linear associations of injuries with typical (far-from-extreme) temperatures. This large population-based study highlights the significant and independent effects of short-term air temperature changes (especially cold) in triggering out_OI. These findings represent the first step towards developing a geographically differentiated, operative outdoor-temperature-occupational-health warning system aimed at preventing outdoor work injuries. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Geographical variation in species' population responses to changes in temperature and precipitation.

PubMed

Pearce-Higgins, James W; Ockendon, Nancy; Baker, David J; Carr, Jamie; White, Elizabeth C; Almond, Rosamunde E A; Amano, Tatsuya; Bertram, Esther; Bradbury, Richard B; Bradley, Cassie; Butchart, Stuart H M; Doswald, Nathalie; Foden, Wendy; Gill, David J C; Green, Rhys E; Sutherland, William J; Tanner, Edmund V J

2015-11-07

Despite increasing concerns about the vulnerability of species' populations to climate change, there has been little overall synthesis of how individual population responses to variation in climate differ between taxa, with trophic level or geographically. To address this, we extracted data from 132 long-term (greater than or equal to 20 years) studies of population responses to temperature and precipitation covering 236 animal and plant species across terrestrial and freshwater habitats. Our results identify likely geographical differences in the effects of climate change on populations and communities in line with macroecological theory. Temperature tended to have a greater overall impact on populations than precipitation, although the effects of increased precipitation varied strongly with latitude, being most positive at low latitudes. Population responses to increased temperature were generally positive, but did not vary significantly with latitude. Studies reporting significant climatic trends through time tended to show more negative effects of temperature and more positive effects of precipitation upon populations than other studies, indicating climate change has already impacted many populations. Most studies of climate change impacts on biodiversity have focused on temperature and are from middle to high northern latitudes. Our results suggest their findings may be less applicable to low latitudes. © 2015 The Author(s).

Climate Change and Phenology: Empoasca fabae (Hemiptera: Cicadellidae) Migration and Severity of Impact

PubMed Central

Lamp, William O.

2015-01-01

Climate change can benefit individual species, but when pest species are enhanced by warmer temperatures agricultural productivity may be placed at greater risk. We analyzed the effects of temperature anomaly on arrival date and infestation severity of potato leafhopper, Empoasca fabae Harris, a classic new world long distance migrant, and a significant pest in several agricultural crops. We compiled E. fabae arrival dates and infestation severity data at different states in USA from existing literature reviews and agricultural extension records from 1951–2012, and examined the influence of temperature anomalies at each target state or overwintering range on the date of arrival and severity of infestation. Average E. fabae arrival date at different states reveal a clear trend along the south-north axis, with earliest arrival closest to the overwintering range. E. fabae arrival has advanced by 10 days over the last 62 years. E. fabae arrived earlier in warmer years in relation to each target state level temperature anomaly (3.0 days / °C increase in temperature anomaly). Increased temperature had a significant and positive effect on the severity of infestation, and arrival date had a marginal negative effect on severity. These relationships suggest that continued warming could advance the time of E. fabae colonization and increase their impact on affected crops. PMID:25970705

Influence of roasting conditions on health-related compounds in different nuts.

PubMed

Schlörmann, W; Birringer, M; Böhm, V; Löber, K; Jahreis, G; Lorkowski, S; Müller, A K; Schöne, F; Glei, M

2015-08-01

Due to their health-beneficial ingredients the consumption of nuts can contribute to a healthy diet. The composition of hazelnuts, almonds, macadamia nuts, pistachios and walnuts regarding health-promoting and potentially harmful compounds was examined before and after roasting under different time and temperature conditions. Fatty acid compositions were not affected by roasting. Malondialdehyde increased with higher roasting temperatures (17-fold in walnuts). Levels of tocopherol isomers were reduced after roasting (α-T: 38%, β-T: 40%, γ-T: 70%) and hydrophilic antioxidant capacity decreased significantly in hazelnuts (1.4-fold), macadamia nuts (1.7-fold) and walnuts (3.7-fold). Increasing roasting temperatures supported the formation of significant amounts of acrylamide only in almonds (1220 μg kg(-1)). In general, nuts roasted at low/middle temperatures (120-160°C) exhibited best sensory properties. Therefore, desired sensory quality along with a favourable healthy nut composition may be achieved by roasting over a low to medium temperature range. Copyright © 2015 Elsevier Ltd. All rights reserved.

Strengthening Mechanisms in Thermomechanically Processed NbTi-Microalloyed Steel

NASA Astrophysics Data System (ADS)

Kostryzhev, Andrii G.; Marenych, Olexandra O.; Killmore, Chris R.; Pereloma, Elena V.

2015-08-01

The effect of deformation temperature on microstructure and mechanical properties was investigated for thermomechanically processed NbTi-microalloyed steel with ferrite-pearlite microstructure. With a decrease in the finish deformation temperature at 1348 K to 1098 K (1075 °C to 825 °C) temperature range, the ambient temperature yield stress did not vary significantly, work hardening rate decreased, ultimate tensile strength decreased, and elongation to failure increased. These variations in mechanical properties were correlated to the variations in microstructural parameters (such as ferrite grain size, solid solution concentrations, precipitate number density and dislocation density). Calculations based on the measured microstructural parameters suggested the grain refinement, solid solution strengthening, precipitation strengthening, and work hardening contributed up to 32 pct, up to 48 pct, up to 25 pct, and less than 3 pct to the yield stress, respectively. With a decrease in the finish deformation temperature, both the grain size strengthening and solid solution strengthening increased, the precipitation strengthening decreased, and the work hardening contribution did not vary significantly.

Climate change and frog calls: long-term correlations along a tropical altitudinal gradient

PubMed Central

Narins, Peter M.; Meenderink, Sebastiaan W. F.

2014-01-01

Temperature affects nearly all biological processes, including acoustic signal production and reception. Here, we report on advertisement calls of the Puerto Rican coqui frog (Eleutherodactylus coqui) that were recorded along an altitudinal gradient and compared these with similar recordings along the same altitudinal gradient obtained 23 years earlier. We found that over this period, at any given elevation, calls exhibited both significant increases in pitch and shortening of their duration. All of the observed differences are consistent with a shift to higher elevations for the population, a well-known strategy for adapting to a rise in ambient temperature. Using independent temperature data over the same time period, we confirm a significant increase in temperature, the magnitude of which closely predicts the observed changes in the frogs’ calls. Physiological responses to long-term temperature rises include reduction in individual body size and concomitantly, population biomass. These can have potentially dire consequences, as coqui frogs form an integral component of the food web in the Puerto Rican rainforest. PMID:24718765

Climate change and frog calls: long-term correlations along a tropical altitudinal gradient.

PubMed

Narins, Peter M; Meenderink, Sebastiaan W F

2014-05-22

Temperature affects nearly all biological processes, including acoustic signal production and reception. Here, we report on advertisement calls of the Puerto Rican coqui frog (Eleutherodactylus coqui) that were recorded along an altitudinal gradient and compared these with similar recordings along the same altitudinal gradient obtained 23 years earlier. We found that over this period, at any given elevation, calls exhibited both significant increases in pitch and shortening of their duration. All of the observed differences are consistent with a shift to higher elevations for the population, a well-known strategy for adapting to a rise in ambient temperature. Using independent temperature data over the same time period, we confirm a significant increase in temperature, the magnitude of which closely predicts the observed changes in the frogs' calls. Physiological responses to long-term temperature rises include reduction in individual body size and concomitantly, population biomass. These can have potentially dire consequences, as coqui frogs form an integral component of the food web in the Puerto Rican rainforest.

Phase-Field Simulation of Concentration and Temperature Distribution During Dendritic Growth in a Forced Liquid Metal Flow

NASA Astrophysics Data System (ADS)

Du, Lifei; Zhang, Rong

2014-12-01

A phase-field model with convection is employed to investigate the effect of liquid flow on the dendritic structure formation of a Ni-Cu alloy during rapid solidification. Temperature and solute diffusion are significantly changed with induced liquid metal flow, and distribution changes of concentration and temperature are also analyzed and discussed. The solute segregation is affected due to the concentration diffusion layer thickness change caused by the liquid flow. The flow reduces the solute segregation in the upstream and leads to a fast dendrite growing, while solidifying in the downstream gets constrained with the large solute diffusion layer. Increasing flow velocity increases the asymmetry of dendrite morphology with much more suppressed growth in the downstream. The temperature distribution is also asymmetrical due to the non-uniform latent heat released during solidification coupling with heat diffusion changed by the liquid flow. Therefore, the forced liquid flow significantly affects the dendrite morphology, concentration, and temperature distributions in the solidifying microstructure.

Halogen and LED light curing of composite: temperature increase and Knoop hardness.

PubMed

Schneider, L F; Consani, S; Correr-Sobrinho, L; Correr, A B; Sinhoreti, M A

2006-03-01

This study assessed the Knoop hardness and temperature increase provided by three light curing units when using (1) the manufacturers' recommended times of photo-activation and (2) standardizing total energy density. One halogen--XL2500 (3M/ESPE)--and two light-emitting diode (LED) curing units--Freelight (3M/ESPE) and Ultrablue IS (DMC)--were used. A type-K thermocouple registered the temperature change produced by the composite photo-activation in a mold. Twenty-four hours after the photo-activation procedures, the composite specimens were submitted to a hardness test. Both temperature increase and hardness data were submitted to ANOVA and Tukey's test (5% significance). Using the first set of photo-activation conditions, the halogen unit produced a statistically higher temperature increase than did both LED units, and the Freelight LED resulted in a lower hardness than did the other curing units. When applying the second set of photo-activation conditions, the two LED units produced statistically greater temperature increase than did the halogen unit, whereas there were no statistical differences in hardness among the curing units.

Relationship between ambient temperature and humidity and visits to mental health emergency departments in Québec.

PubMed

Vida, Stephen; Durocher, Martin; Ouarda, Taha B M J; Gosselin, Pierre

2012-11-01

This study examined whether the number of emergency department visits for "mental and psychosocial problems" varies with temperature or humidity. The number of visits in three geographic areas of Québec were examined as a function of temperature and humidity by using routinely collected May-September data for 1995-2007 (N=347,552 visits). Data for two age groups (under age 65 and age 65 and older) were examined. Incidence rate ratios for mean temperature and humidity were estimated by using Poisson regression and generalized additive models. The number of visits tended to increase with increasing mean temperature. At 22.5 °C (72.5 °F) and 25 °C (77.0 °F), the number was usually significantly higher than average. Visits increased with humidity in the younger age group. Results suggest increased use of emergency departments for mental and psychosocial problems with higher mean temperature and humidity, especially in metropolitan areas and in southern Québec. Climate change may make this effect increasingly important.

Effects of heat stress on some reproductive parameters of male cavie (Cavia porcellus) and mitigation strategies using guava (Psidium guajava) leaves essential oil.

PubMed

Ngoula, Ferdinand; Guemdjo Tekam, Maryvonne; Kenfack, Augustave; Tadondjou Tchingo, Cyrille D'Alex; Nouboudem, Sandrine; Ngoumtsop, Herman; Tsafack, Borice; Teguia, Alexis; Kamtchouing, Pierre; Galeotti, Marco; Tchoumboue, Joseph

2017-02-01

Climate changes, particularly the increase of temperature are among the main causes behind the decline of fertility in humans as well as animals. In this study, the effects of heat stress on some reproductive parameters of male cavies and mitigation strategies using guava leaves essential oil (GLEO) were studied. For this purpose, 40 male cavies aged 2.5-3 months and weighing between 348 and 446g were divided into 4 groups of 10 animals each and subjected to the following temperatures: Ambient temperature (20-25°C) for the control group, 35°C for group 1, 45°C for group 2 and 45°C+100µl GLEO/kg body weight, administered by gavage to animals for group 3. Exposure time of heat was 7h per day for 60 days. Results reveal that the relative weights of testes, epididymis, vas deferens and seminal vesicles were hardly affected by the temperature levels considered (P>0.05). The mass and individual sperm motility was significantly lower (P<0.05) in cavies exposed to the temperature of 35 and 45°C as compared with those which received GLEO and controls. The percentages of abnormal sperm and altered sperm DNA were higher in animals exposed to temperature of 35 and 45°C as compared with the controls. The activity of superoxide dismutase significantly increased (P<0.05) in animals exposed to temperature of 45°C and in those of 45°C and orally treated with GLEO, compared with cavies exposed to temperature of 45°C without receiving GLEO. The level of malondialdehyde was significantly increased (P<0.05) in animals exposed to temperature of 35 and 45°C, whereas the level of nitric oxide was significantly lower (P<0.05) in exposed animals as compared with controls. It was concluded that the exposure of male cavies at 35 and 45°C for 60 days induce heat stress that causes deterioration of sperm characteristics. These effects that can be mitigated by the administration of guava leaves essential oil. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatio-temporal Patterns of Vegetation and Its Relationship with Precipitation and Temperature in the Yarlung Zangbo River Basin, China

NASA Astrophysics Data System (ADS)

LIU, X.; Xu, Z.; Peng, D.

2017-12-01

Vegetation growth plays a significant role on runoff variation at high altitude, and precipitation and temperature are both key factors affecting vegetation conditions. As one of the greatest international rivers in China, the Yarlung Zangbo River in the southern Qinghai-Tibetan Plateau was selected, and the spatio-temporal patterns of vegetation were analyzed by using NDVI (Normalized Difference Vegetation Index) during 1998 2014. The relationship between NDVI and precipitation as well as temperature was also investigated in this study. Results showed that the value of NDVI increases with the decrease of elevation and the largest value appears in the broadleaf forest cover. Almost all annual NDVI variations exhibit an increasing tendency, particularly for the broadleaf forest cover. On the viewpoint of statistics, only 29% pixels of NDVI with increasing tendency are of significance for the other cover, while for cultivated vegetation cover, around 82% pixels of NDVI were detected with significant increasing tendency. In addition, vegetation growth showed lagging response to precipitation, and the lag time is around one month. Moreover, in the region with elevation over 5000 m, negative relationship between NDVI and precipitation for alpine vegetation was found. Approximately 75% of NDVI variations are dominated by precipitation and temperature. These findings may provide a reference to investigate runoff variations and strengthen ecological protection for similar high-altitude areas in the future.

Detection of spatio-temporal variability of air temperature and precipitation based on long-term meteorological station observations over Tianshan Mountains, Central Asia

NASA Astrophysics Data System (ADS)

Xu, Min; Kang, Shichang; Wu, Hao; Yuan, Xu

2018-05-01

As abundant distribution of glaciers and snow, the Tianshan Mountains are highly vulnerable to changes in climate. Based on meteorological station records during 1960-2016, we detected the variations of air temperature and precipitation by using non-parametric method in the different sub-regions and different elevations of the Tianshan Mountains. The mutations of climate were investigated by Mann-Kendall abrupt change test in the sub-regions. The periodicity is examined by wavelet analysis employing a chi-square test and detecting significant time sections. The results show that the Tianshan Mountains experienced an overall rapid warming and wetting during study period, with average warming rate of 0.32 °C/10a and wet rate of 5.82 mm/10a, respectively. The annual and seasonal spatial variation of temperature showed different scales in different regions. The annual precipitation showed non-significant upward trend in 20 stations, and 6 stations showed a significant upward trend. The temperatures in the East Tianshan increased most rapidly at rates of 0.41 °C/10a. The increasing magnitudes of annual precipitation were highest in the Boertala Vally (8.07 mm/10a) and lowest in the East Tianshan (2.64 mm/10a). The greatest and weakest warming was below 500 m (0.42 °C/10a) and elevation of 1000-1500 m (0.23 °C/10a), respectively. The increasing magnitudes of annual precipitation were highest in the elevation of 1500 m-2000 m (9.22 mm/10a) and lowest in the elevation of below 500 m (3.45 mm/10a). The mutations of annual air temperature and precipitation occurred in 1995 and 1990, respectively. The large atmospheric circulation influenced on the mutations of climate. The significant periods of air temperature were 2.4-4.1 years, and annual precipitation was 2.5-7.4 years. Elevation dependency of temperature trend magnitude was not evidently in the Tianshan Mountains. The annual precipitation wetting trend was amplified with elevation in summer and autumn. The strong elevation dependence of precipitation increasing trend appeared in summer.

The effects of temperature and aeration on the corrosion of A508III low alloy steel in boric acid solutions at 25-95 °C

NASA Astrophysics Data System (ADS)

Xiao, Qian; Lu, Zhanpeng; Chen, Junjie; Yao, Meiyi; Chen, Zhen; Ejaz, Ahsan

2016-11-01

The effects of temperature, solution composition and dissolved oxygen on the corrosion rate and electrochemical behavior of an A508III low alloy steel in boric acid solution with lithium hydroxide at 25-95 °C are investigated. In aerated solutions, increasing the boric acid concentration increases the corrosion rate and the anodic current density. The corrosion rate in deaerated solutions increases with increasing temperature. A corrosion rate peak value is found at approximately 75 °C in aerated solutions. Increasing temperature increases the oxygen diffusion coefficient, decreases the dissolved oxygen concentration, accelerates the hydrogen evolution reaction, and accelerates both the active dissolution and the film forming reactions. Increasing dissolved oxygen concentration does not significantly affect the corrosion rate at 50 and 60 °C, increases the corrosion rate at 70 and 80 °C, and decreases the corrosion rate at 87.5 and 95 °C in a high concentration boric acid solution with lithium hydroxide.

An investigation of fracture toughness, fatigue-crack growth, sustained-load flaw growth, and impact properties of three pressure vessel steels

NASA Technical Reports Server (NTRS)

Hudson, C. M.; Newman, J. C., Jr.; Lewis, P. E.

1975-01-01

The elastic fracture toughness of the three steels is shown to not decrease significantly with decreasing temperature from room temperature to about 244 K (-20 F.). The elastic fracture toughness of the three steels increased with increasing specimen width and thickness. The fatigue-crack-growth data for all three steels fall into relatively narrow scatter bands on plots of rate against stress-intensity range. An equation is shown to predict the upper bounds of the scatter bands reasonably well. Charpy impact energies decreased with decreasing temperature in the nominal temperature range from room temperature to 244 K (-20 F). The nil-ductility temperatures of the steels are discussed.

Effects of environmental temperature change on mercury absorption in aquatic organisms with respect to climate warming.

PubMed

Pack, Eun Chul; Lee, Seung Ha; Kim, Chun Huem; Lim, Chae Hee; Sung, Dea Gwan; Kim, Mee Hye; Park, Ki Hwan; Lim, Kyung Min; Choi, Dal Woong; Kim, Suhng Wook

2014-01-01

Because of global warming, the quantity of naturally generated mercury (Hg) will increase, subsequently methylation of Hg existing in seawater may be enhanced, and the content of metal in marine products rise which consequently results in harm to human health. Studies of the effects of temperatures on Hg absorption have not been adequate. In this study, in order to observe the effects of temperature changes on Hg absorption, inorganic Hg or methylmercury (MeHg) was added to water tanks containing loaches. Loach survival rates decreased with rising temperatures, duration, and exposure concentrations in individuals exposed to inorganic Hg and MeHg. The MeHg-treated group died sooner than the inorganic Hg-exposed group. The total Hg and MeHg content significantly increased with temperature and time in both metal-exposed groups. The MeHg-treated group had higher metal absorption rates than inorganic Hg-treated loaches. The correlation coefficients for temperature elevation and absorption were significant in both groups. The results of this study may be used as basic data for assessing in vivo hazards from environmental changes such as climate warming.

Improvement of Superplasticity in High-Mg Aluminum Alloys by Sacrifice of Some Room Temperature Formability

NASA Astrophysics Data System (ADS)

Jin, H.; Amirkhiz, B. Shalchi; Lloyd, D. J.

2018-03-01

The mechanical properties of fully annealed Al-4.6 wt pct Mg alloys with different levels of Mn and Fe have been characterized at room and superplastic forming (SPF) temperatures. The effects of Mn and Fe on the intermetallic phase, grain structure, and cavitation were investigated and correlated to the formability at different temperatures. Although both Mn and Fe contribute to the formation of Al6(Mn,Fe) phase, which refines the grain structure by particle-stimulated nucleation and Zener pinning, their effects are different. An increasing Mn reduces the room temperature formability due to the increasing number of intermetallic particles, but significantly improves the superplasticity by fine grain size-induced grain boundary sliding. Meanwhile, the Fe makes the constituent particles very coarse, resulting in reduced formability at all temperatures due to extensive cavitation. A combination of high Mn and low Fe is therefore beneficial to SPF, while low levels of both elements are good for cold forming. Consequently, the superplasticity of high-Mg aluminum alloys can be significantly improved by modifying the chemical composition with sacrifice of some room temperature formability.

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.

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

PubMed

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

2015-02-01

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

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).

The effect of temperature on the resting and post-exercise metabolic rates and aerobic metabolic scope in shortnose sturgeon Acipenser brevirostrum.

PubMed

Zhang, Yueyang; Kieffer, James D

2017-10-01

The effects of acclimation temperature (15, 20, 25 °C) on routine oxygen consumption and post-exercise maximal oxygen consumption rates (MO 2 ) were measured in juvenile shortnose sturgeon (Acipenser brevirostrum LeSueur, 1818). The routine MO 2 of shortnose sturgeon increased significantly from 126.75 mg O 2  h -1  kg -1 at 15 °C to 253.13 mg O 2  h -1  kg -1 at 25 °C. The temperature coefficient (Q 10 ) values of the routine metabolic rates ranged between 1.61 and 2.46, with the largest Q 10 values occurring between 15 and 20 °C. The average post-exercise MO 2 of all temperature groups increased to a peak value immediately following the exercise, with levels increasing about 2-fold among all temperature groups. The Q 10 values for post-exercise MO 2 ranged from 1.21 to 2.12, with the highest difference occurring between 15 and 20 °C. Post-exercise MO 2 values of shortnose sturgeon in different temperature groups all decreased exponentially and statistically returned to pre-exercise (resting) levels by 30 min at 15 and 20 °C and by 60 min at 25 °C. The aerobic metabolic scope (post-exercise maximal MO 2 -routine MO 2 ) increased to a maximum value ∼156 mg O 2  h -1  kg -1 at intermediate experimental temperatures (i.e., 20 °C) and then decreased as the temperature increased to 25 °C. However, this trend was not significant. The results suggest that juvenile shortnose sturgeon show flexibility in their ability to adapt to various temperature environments and in their responses to exhaustive exercise.

Autonomous Aerobraking Using Thermal Response Surface Analysis

NASA Technical Reports Server (NTRS)

Prince, Jill L.; Dec, John A.; Tolson, Robert H.

2007-01-01

Aerobraking is a proven method of significantly increasing the science payload that can be placed into low Mars orbits when compared to an all propulsive capture. However, the aerobraking phase is long and has mission cost and risk implications. The main cost benefit is that aerobraking permits the use of a smaller and cheaper launch vehicle, but additional operational costs are incurred during the long aerobraking phase. Risk is increased due to the repeated thermal loading of spacecraft components and the multiple attitude and propulsive maneuvers required for successful aerobraking. Both the cost and risk burdens can be significantly reduced by automating the aerobraking operations phase. All of the previous Mars orbiter missions that have utilized aerobraking have increasingly relied on onboard calculations during aerobraking. Even though the temperature of spacecraft components has been the limiting factor, operational methods have relied on using a surrogate variable for mission control. This paper describes several methods, based directly on spacecraft component maximum temperature, for autonomously predicting the subsequent aerobraking orbits and prescribing apoapsis propulsive maneuvers to maintain the spacecraft within specified temperature limits. Specifically, this paper describes the use of thermal response surface analysis in predicting the temperature of the spacecraft components and the corresponding uncertainty in this temperature prediction.

Significant increase of Curie temperature in nano-scale BaTiO{sub 3}

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

Li, Yueliang; Liao, Zhenyu; Fang, Fang

2014-11-03

The low Curie temperature (T{sub c} = 130 °C) of bulk BaTiO{sub 3} greatly limits its applications. In this work, the phase structures of BaTiO{sub 3} nanoparticles with sizes ranging from 2.5 nm to 10 nm were studied at various temperatures by using aberration-corrected transmission electron microscopy (TEM) equipped with an in-situ heating holder. The results implied that each BaTiO{sub 3} nanoparticle was composed of different phases, and the ferroelectric ones were observed in the shells due to the complicated surface structure. The ferroelectric phases in BaTiO{sub 3} nanoparticles remained at 600 °C, suggesting a significant increase of T{sub c}. Based on the in-situ TEM resultsmore » and the data reported by others, temperature-size phase diagrams for BaTiO{sub 3} particles and ceramics were proposed, showing that the phase transition became diffused and the T{sub c} obviously increased with decreasing size. The present work sheds light on the design and fabrication of advanced devices for high temperature applications.« less

Observed Trends in Indices of Daily Precipitation and Temperature Extremes in Rio de Janeiro State (brazil)

NASA Astrophysics Data System (ADS)

Silva, W. L.; Dereczynski, C. P.; Cavalcanti, I. F.

2013-05-01

One of the main concerns of contemporary society regarding prevailing climate change is related to possible changes in the frequency and intensity of extreme events. Strong heat and cold waves, droughts, severe floods, and other climatic extremes have been of great interest to researchers because of its huge impact on the environment and population, causing high monetary damages and, in some cases, loss of life. The frequency and intensity of extreme events associated with precipitation and air temperature have been increased in several regions of the planet in recent years. These changes produce serious impacts on human activities such as agriculture, health, urban planning and development and management of water resources. In this paper, we analyze the trends in indices of climatic extremes related to daily precipitation and maximum and minimum temperatures at 22 meteorological stations of the National Institute of Meteorology (INMET) in Rio de Janeiro State (Brazil) in the last 50 years. The present trends are evaluated using the software RClimdex (Canadian Meteorological Service) and are also subjected to statistical tests. Preliminary results indicate that periods of drought are getting longer in Rio de Janeiro State, except in the North/Northwest area. In "Vale do Paraíba", "Região Serrana" and "Região dos Lagos" the increase of consecutive dry days is statistically significant. However, we also detected an increase in the total annual rainfall all over the State (taxes varying from +2 to +8 mm/year), which are statistically significant at "Região Serrana". Moreover, the intensity of heavy rainfall is also growing in most of Rio de Janeiro, except in "Costa Verde". The trends of heavy rainfall indices show significant increase in the "Metropolitan Region" and in "Região Serrana", factor that increases the vulnerability to natural disasters in these areas. With respect to temperature, it is found that the frequency of hot (cold) days and nights is increasing (reducing) with significance in almost all regions. "Região dos Lagos" has the most significant trends of increasing in temperature, thereby influencing the local production of salt and alkaline minerals in medium and long term. The goal of this research is, through the analysis of results, support studies of vulnerability and adaptation to climate change scenarios in Rio de Janeiro State.

Modelling the effect of temperature change on the extrinsic incubation period and reproductive number of Plasmodium falciparum in Malaysia.

PubMed

Chua, T H

2012-03-01

According to the report of the Intergovernmental Panel on Climate Change (IPCC), Malaysia will experience an increase of 3-5°C in the future. As the development of the malaria parasite, Plasmodium falciparum, is sensitive to temperature, we investigated, using computer models, the effect of increase of 3º and 5ºC on the possible changes in the epidemiology of malaria transmission of P. falciparum in Malaysia. Four environmentally different locations were selected: Kuala Lumpur (KL), Cameron Highlands (CH), Kota Kinabalu (KK) and Kinabalu Park (KP). The extrinsic incubation period (EIP) was estimated using hourly temperatures and the mean daily temperatures. The EIP values estimated using the mean daily temperature were lower than those computed from hourly temperatures in warmer areas (KL, KK), but higher in the cooler areas (CH, KP). The computer simulations also indicated that the EIP will be decreased if the temperature was raised by 3º or 5ºC, with the effect more pronounced for the greater temperature increase, and for the cooler places. The vector cohort that is still alive at a time to transmit malaria (s(EIP)) also increased when the temperature was raised, with the increase more pronounced in the cooler areas. This study indicates an increase in temperature will have more significant effect in shortening the EIP in a cooler place (eg CH, KP), resulting in a greater s(EIP), and consequently increasing the transmission intensity and malaria risk. A temperature increase arising from the global climate change will likely affect the epidemiology of malaria in Malaysia, especially in the cooler areas.

Experimental investigation of the 100 keV X-ray dose response of the high-temperature thermoluminescence in LiF:Mg,Ti (TLD-100): theoretical interpretation using the unified interaction model.

PubMed

Livingstone, J; Horowitz, Y S; Oster, L; Datz, H; Lerch, M; Rosenfeld, A; Horowitz, A

2010-03-01

The dose response of LiF:Mg,Ti (TLD-100) chips was measured from 1 to 50,000 Gy using 100 keV X rays at the European Synchroton Radiation Facility. Glow curves were deconvoluted into component glow peaks using a computerised glow curve deconvolution (CGCD) code based on first-order kinetics. The normalised dose response, f(D), of glow peaks 4 and 5 and 5b (the major components of composite peak 5), as well as peaks 7 and 8 (two of the major components of the high-temperature thermoluminescence (HTTL) at high levels of dose) was separately determined and theoretically interpreted using the unified interaction model (UNIM). The UNIM is a nine-parameter model encompassing both the irradiation/absorption stage and the thermally induced relaxation/recombination stage with an admixture of both localised and delocalised recombination mechanisms. The effects of radiation damage are included in the present modelling via the exponential removal of luminescent centres (LCs) at high dose levels. The main features of the experimentally measured dose response are: (i) increase in f(D)(max) with glow peak temperature, (ii) increase in D(max) (the dose level at which f(D)(max) occurs) with increasing glow peak temperature, and (iii) decreased effects of radiation damage with increasing glow peak temperature. The UNIM interpretation of this behaviour requires both strongly decreasing values of ks (the relative contribution of localised recombination) as a function of glow peak temperature and, as well, significantly different values of the dose-filling constants of the trapping centre (TC) and LC for peaks 7 and 8 than those used for peaks 4 and 5. This suggests that different TC/LC configurations are responsible for HTTL. The relative intensity of peak 5a (a low-temperature satellite of peak 5 arising from localised recombination) was found to significantly increase at higher dose levels due to preferential electron and hole population of the trapping/recombination complex giving rise to composite glow peak 5. It is also demonstrated that possible changes in the trapping cross section of the LC and the competitive centres due to increasing sample/glow peak temperature do not significantly influence these observations/conclusions.

Impacts of warming revealed by linking resource growth rates with consumer functional responses.

PubMed

West, Derek C; Post, David M

2016-05-01

Warming global temperatures are driving changes in species distributions, growth and timing, but much uncertainty remains regarding how climate change will alter species interactions. Consumer-Resource interactions in particular can be strongly impacted by changes to the relative performance of interacting species. While consumers generally gain an advantage over their resources with increasing temperatures, nonlinearities can change this relation near temperature extremes. We use an experimental approach to determine how temperature changes between 5 and 30 °C will alter the growth of the algae Scenedesmus obliquus and the functional responses of the small-bodied Daphnia ambigua and the larger Daphnia pulicaria. The impact of warming generally followed expectations, making both Daphnia species more effective grazers, with the increase in feeding rates outpacing the increases in algal growth rate. At the extremes of our temperature range, however, warming resulted in a decrease in Daphnia grazing effectiveness. Between 25 and 30 °C, both species of Daphnia experienced a precipitous drop in feeding rates, while algal growth rates remained high, increasing the likelihood of algal blooms in warming summer temperatures. Daphnia pulicaria performed significantly better at cold temperatures than D. ambigua, but by 20 °C, there was no significant difference between the two species, and at 25 °C, D. ambigua outperformed D. pulicaria. Warming summer temperatures will favour the smaller D. ambigua, but only over a narrow temperature range, and warming beyond 25 °C could open D. ambigua to invasion from tropical species. By fitting our results to temperature-dependent functions, we develop a temperature- and density-dependent model, which produces a metric of grazing effectiveness, quantifying the grazer density necessary to halt algal growth. This approach should prove useful for tracking the transient dynamics of other density-dependent consumer-resource interactions, such as agricultural pests and biological-control agents. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

Analytical studies into radiation-induced starch damage in black and white peppers

NASA Astrophysics Data System (ADS)

Sharif, M. M.; Farkas, J.

1993-07-01

Temperature dependency of the apparent viscosity of heat-gelatinized suspensions of untreated and irradiated pepper samples has been investigated. There was a close linear correlation between the logaritm of "fluidity" /reciprocal of the apparent viscosity) and the reciprocal absolute temperature of the measurement. The slope of the regression line(the temperature dependence of fluidity) increased with the radiation dose. Gelatinization thermograms of aqueous suspensions of ground pepper samples were obtained by differential scanning calorimetry. Temperature characteristics of heat-gelatinization endotherms showed no significant differences between untreated and irradiated samples. A colorimetric method for damaged starch, the estimation of reducing power, and the alcohol-induced turbidity of aqueous extracts showed statistically significant increases of starch damage at doses higher than 4 kGy. These indices of starch-depolymerization have been changed less dramatically by irradiation than the apparent viscosity of the heat-gelatinized suspensions.

Influence of temperature on the myocardial cells death by an extracellular talaporfin sodium-induced photosensitization reaction

NASA Astrophysics Data System (ADS)

Ogawa, Emiyu; Takenoya, Hiromi; Arai, Tsunenori

2016-03-01

We have proposed to apply the photosensitization reaction in myocardium interstitial fluid using talaporfin sodium to realize less-heated electrical conduction block for a tachyarrhythmia treatment: PD Ablation®. The cytotoxicity of the extracellular photosensitization reaction efficiency may change by the talaporfin sodium binding with serum proteins. These binding would change with solution temperature. We investigated the binding behavior of talaporfin sodium with human serum albumin (HSA), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) changing solution temperature from 17 to 37°C. We also studied the photocytotoxicity change by solution temperature of 17 and 37°C measuring cell lethality by WST assay using fetal bovine serum. The binding ratio of talaporfin sodium with HDL and LDL decreased 6.3% and 12.8% with temperature increasing from 17 to 37°C. There was no significant difference in the case of HSA. The cell lethality was increased about 30% with temperature increasing from 17 to 37°C. The myocardium tissue temperature increase was reported that less than 5°C in the case of our PD Ablation®. We think that the photocytotoxicity change by these temperature increasing would be negligible in our PD Ablation®. We suggest that the temperature maintaining would be necessary to keep the photocytotoxicity efficiency in the case of the open surgery that would cause the tissue surface temperature decreasing.

Increased Night Temperature Negatively Affects Grain Yield, Biomass and Grain Number in Chilean Quinoa

PubMed Central

Lesjak, Jurka; Calderini, Daniel F.

2017-01-01

Quinoa high nutritive value increases interest worldwide, especially as a crop that could potentially feature in different cropping systems, however, climate change, particularly rising temperatures, challenges this and other crop species. Currently, only limited knowledge exists regarding the grain yield and other key traits response to higher temperatures of this crop, especially to increased night temperatures. In this context, the main objective of this study was to evaluate the effect of increased night temperature on quinoa yield, grain number, individual grain weight and processes involved in crop growth under the environmental conditions (control treatment) and night thermal increase at two phases: flowering (T1) and grain filling (T2) in southern Chile. A commercial genotype, Regalona, and a quinoa accession (Cod. BO5, N°191, grain bank from Semillas Baer, hereby referred to as Accession) were used, due to their adaptability to Southern Chilean conditions and contrasting grain yield potential, grain weight and size of plants. Temperature was increased ≈4°C above the ambient from 8 pm until 9 am the next morning. Control treatments reached a high grain yield (600 and 397 g m-2, i.e., Regalona and Accession). Temperature increase reduced grain yield by 31% under T1 treatment and 12% when under T2 in Regalona and 23 and 26% in Accession, respectively. Aboveground biomass was negatively affected by the thermal treatments and a positive linear association was found between grain yield and aboveground biomass across treatments. By contrast, the harvest index was unaffected either by genotype, or by thermal treatments. Grain number was significantly affected between treatments and this key trait was linearly associated with grain yield. On the other hand, grain weight showed a narrow range of variation across treatments. Additionally, leaf area index was not affected, but significant differences were found in SPAD values at the end of T1 treatment, compared to control. Little change was found in the harvest index, individual grain weight, grain protein content or water soluble carbohydrates in response to the increased night temperature in this crop. PMID:28386266

Convective Heat Transfer with and without Film Cooling in High Temperature, Fuel Rich and Lean Environments

NASA Astrophysics Data System (ADS)

Greiner, Nathan J.

Modern turbine engines require high turbine inlet temperatures and pressures to maximize thermal efficiency. Increasing the turbine inlet temperature drives higher heat loads on the turbine surfaces. In addition, increasing pressure ratio increases the turbine coolant temperature such that the ability to remove heat decreases. As a result, highly effective external film cooling is required to reduce the heat transfer to turbine surfaces. Testing of film cooling on engine hardware at engine temperatures and pressures can be exceedingly difficult and expensive. Thus, modern studies of film cooling are often performed at near ambient conditions. However, these studies are missing an important aspect in their characterization of film cooling effectiveness. Namely, they do not model effect of thermal property variations that occur within the boundary and film cooling layers at engine conditions. Also, turbine surfaces can experience significant radiative heat transfer that is not trivial to estimate analytically. The present research first computationally examines the effect of large temperature variations on a turbulent boundary layer. Subsequently, a method to model the effect of large temperature variations within a turbulent boundary layer in an environment coupled with significant radiative heat transfer is proposed and experimentally validated. Next, a method to scale turbine cooling from ambient to engine conditions via non-dimensional matching is developed computationally and the experimentally validated at combustion temperatures. Increasing engine efficiency and thrust to weight ratio demands have driven increased combustor fuel-air ratios. Increased fuel-air ratios increase the possibility of unburned fuel species entering the turbine. Alternatively, advanced ultra-compact combustor designs have been proposed to decrease combustor length, increase thrust, or generate power for directed energy weapons. However, the ultra-compact combustor design requires a film cooled vane within the combustor. In both these environments, the unburned fuel in the core flow encounters the oxidizer rich film cooling stream, combusts, and can locally heat the turbine surface rather than the intended cooling of the surface. Accordingly, a method to quantify film cooling performance in a fuel rich environment is prescribed. Finally, a method to film cool in a fuel rich environment is experimentally demonstrated.

Climate change in Lagos state, Nigeria: what really changed?

PubMed

Sojobi, Adebayo Olatunbosun; Balogun, Isaac Idowu; Salami, Adebayo Wahab

2015-10-01

Our study revealed periodicities of 2.3 and 2.25 years in wet and dry seasons and periodicities of 2 to 5 years on seasonal and annual timescales. Minimum temperature (Tmin), maximum temperature (Tmax) and evaporation recorded increases of 2.47, 1.37 and 28.37 %, respectively, but a reduction of 19.58 % in rainfall on decadal timescale. Periodicity of 8 to 12 years was also observed in annual Tmax. Cramer's test indicated a warming trend with significant Tmax increase in February, April, July, August, October and November during 2000-2009 on decadal monthly timescale, a significant decline in Summer rainfall but significant Tmax increase in Spring, Autumn and Winter on decadal seasonal timescale. The low correlation of rainfall with temperature parameters and evaporation indicates that advection of moisture into Lagos State seems to be the dominant mechanism controlling rainfall within the State alongside other tropical and extra-tropical factors. In addition, our study revealed that the persistent state of minimum temperature often precedes the arrival and reversal of the phase of maximum temperature. Furthermore, our study also revealed that extreme and high variable rainfalls, which are associated with the increased warming trend, had periodicities of 1 to 3 years with a probability of 86.45 % of occurring every 3 years between April and September. It is recommended that government and private sector should give financial and technical supports to climate researches in order to appropriately inform policy making to improve the adaptive capacity and resilience of Lagos State against climate change impacts and guard against maladaptation.

The combined effects of storage temperature and packaging on the sensory, chemical, and physical properties of a Cabernet Sauvignon wine.

PubMed

Hopfer, Helene; Buffon, Peter A; Ebeler, Susan E; Heymann, Hildegarde

2013-04-03

A Californian Cabernet Sauvignon was stored for 6 months at three different constant temperatures to study the combined effects of storage temperature and packaging configuration. Glass bottles with natural cork, synthetic cork, and screw cap closure, as well as two Bag-in-Box treatments, were used in the experiment. A trained sensory panel was able to detect significant changes in aroma, flavor, taste, mouthfeel, and color attributes among the samples, differences that were found also with various chemical and physical measurements (volatile profile, polyphenol pattern, enological parameters, color space). Additionally, two commonly used polyphenol assays were compared to each other in terms of their ability to detect the changes in the polyphenol profile. Generally, sample changes were more pronounced due to the different storage temperatures, with 30 sensory attributes differing significantly among the three different storage temperatures, while only 17 sensory attributes showed a significant packaging effect. With increasing storage temperature the packaging effect became more pronounced, resulting in the largest changes in the Bag-in-Box samples stored at the highest temperature of 40 °C. At the highest storage temperature, all wines showed oxidized characters, independent of the wine packaging configurations, but to a varying degree. Generally, wines that received highest oxygen amounts and storage temperatures were much lighter, less red, and more brown-yellow at the end of the 6-month storage period, compared to their counterparts stored at 10 °C. These changes in color and polyphenols, respectively, were also detected with the two spectrophotometric assays. With increasing storage temperature both assays measured reduced concentrations in total phenols and total anthocyanins, while total tannins, degree of ionized anthocyanins, and color density increased. Various volatile compounds differed significantly among the samples, with largest relative concentration changes in acetates, organic acids, and alcohols, in good agreement with previous literature reports, with some being well correlated to specific sensory attributes too; for example, various acetates correlated to cherry and fruit aromas and flavors. The study shows that storage at elevated temperatures could be a valuable tool for wine packaging screening and testing new and improved wine packaging types under the worst conditions, which are unfortunately not unrealistic.

Effect of temperature on life history traits during immature development of Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae) from Córdoba city, Argentina.

PubMed

Grech, Marta G; Sartor, Paolo D; Almirón, Walter R; Ludueña-Almeida, Francisco F

2015-06-01

We investigated how ambient temperature under fluctuating conditions affects the larval-pupal immature traits of Aedes aegypti and Culex quinquefasciatus mosquitoes from Córdoba city, Argentina, and established each species development threshold and physiological time. Based on life tables, three cohorts of each mosquito species were reared in the laboratory under small fluctuating temperatures conditions of 15.2±1.7°C, 17.9±1.6°C, 21.6±0.7°C and 25.3±0.4°C for Ae. aegypti, and 16.6±1.7°C, 18.7±1.7°C and 25.2±0.3°C for Cx. quinquefasciatus. Immature development time and survival values, and also thermal development threshold and physiological time were estimated. Development times of all larval and pupal stages of Ae. aegypti and Cx. quinquefasciatus were significantly affected by the rearing temperatures, decreasing when temperature increased. Mean Ae. aegypti total (larva+pupa) development time ranged from 21.9 to 8.6 days, at 15.2 and 25.3°C, whereas, for Cx. quinquefasciatus varied between 23.5 to 9.2 days at 16.6 and 25.2°C, respectively. Larval and pupal survival of both species was affected by different rearing temperatures, increasing in general as temperature increased. For Ae. aegypti the total immature survival ranged from 26% at 15.2°C to 92% at 21.6°C; however, temperature did not have significant effect on this variable. The total immature survival of Cx. quinquefasciatus was significantly and positively affected by temperatures, ranging from 32 to 88%, at 16.6 and 25.2°C. The temperature development threshold and the physiological time estimated for Ae. aegypti and Cx. quinquefasciatus were 11.11°C and 93.74 degree-days, and 10.96°C and 136.87 degree-days, respectively. The results of the present study showed that temperature significantly affects the larval-pupal immature traits of these mosquito species of sanitary importance, from the central region of Argentina. All the parameters recorded are useful for the development of mosquito management models. Copyright © 2015 Elsevier B.V. All rights reserved.

The impact of future summer temperature on public health in Barcelona and Catalonia, Spain

NASA Astrophysics Data System (ADS)

Ostro, Bart; Barrera-Gómez, Jose; Ballester, Joan; Basagaña, Xavier; Sunyer, Jordi

2012-11-01

Several epidemiological studies have reported associations between increases in summer temperatures and risks of premature mortality. The quantitative implications of predicted future increases in summer temperature, however, have not been extensively characterized. We have quantified these effects for the four main cities in Catalonia, Spain (Barcelona, Tarragona, Lleida, Girona). We first used case-crossover analysis to estimate the association between temperature and mortality for each of these cities for the period 1983 to 2006. These exposure-response (ER) functions were then combined with local measures of current and projected changes in population, mortality and temperature for the years 2025 and 2050. Predicted daily mean temperatures were based on the A1B greenhouse gas emission, "business-as-usual" scenario simulations derived from the ENSEMBLES project. Several different ER functions were examined and significant associations between temperature and mortality were observed for all four cities. For these four cities, the age-specific piecewise linear model predicts 520 (95%CI 340, 720) additional annual deaths attributable to the change in temperature in 2025 relative to the average from the baseline period of 1960-1990. For 2050, the estimate increases to 1,610 deaths per year during the warm season. For Catalonia as a whole, the point estimates for those two years are 720 and 2,330 deaths per year, respectively, or about 2 and 3% of the warm season. In comparing these predicted impacts with current causes of mortality, they clearly represent significant burdens to public health in Catalonia.

The impact of future summer temperature on public health in Barcelona and Catalonia, Spain.

PubMed

Ostro, Bart; Barrera-Gómez, Jose; Ballester, Joan; Basagaña, Xavier; Sunyer, Jordi

2012-11-01

Several epidemiological studies have reported associations between increases in summer temperatures and risks of premature mortality. The quantitative implications of predicted future increases in summer temperature, however, have not been extensively characterized. We have quantified these effects for the four main cities in Catalonia, Spain (Barcelona, Tarragona, Lleida, Girona). We first used case-crossover analysis to estimate the association between temperature and mortality for each of these cities for the period 1983 to 2006. These exposure-response (ER) functions were then combined with local measures of current and projected changes in population, mortality and temperature for the years 2025 and 2050. Predicted daily mean temperatures were based on the A1B greenhouse gas emission, "business-as-usual" scenario simulations derived from the ENSEMBLES project. Several different ER functions were examined and significant associations between temperature and mortality were observed for all four cities. For these four cities, the age-specific piecewise linear model predicts 520 (95%CI  340, 720) additional annual deaths attributable to the change in temperature in 2025 relative to the average from the baseline period of 1960-1990. For 2050, the estimate increases to 1,610 deaths per year during the warm season. For Catalonia as a whole, the point estimates for those two years are 720 and 2,330 deaths per year, respectively, or about 2 and 3% of the warm season. In comparing these predicted impacts with current causes of mortality, they clearly represent significant burdens to public health in Catalonia.

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 changes in the pulp chamber during dentin ablation with Er:YAG laser

NASA Astrophysics Data System (ADS)

Zhang, Xianzeng; Zhao, Haibin; Zhan, Zhenlin; Guo, Wenqing; Xie, Shusen

2012-12-01

To examine the temperature changes in the pulp chamber during cavity preparation in dentin with the Er:YAG laser (2940 nm), a total 20 intact premolars teeth were divided into 4 groups for dentin ablation with different radiant exposures at 4Hz and 8Hz with and without water spray. A K-type thermocouple was used to monitor the temperature changes in pulp chamber during laser treatment. The total time of irradiation was 70 sec. the water spray rate was 3 mL/min. It showed that maximum temperature rise increases with the increasing of radiant exposure and pulse repetition rate and the additional water cooling during laser ablation can significantly reduce the temperature rise in pulp chamber which will benefit to avoid or reduce thermal damage to tooth structure and dental pulp. The highest rise of temperature in the pulp was achieved with 20 J/cm2 and 8 Hz (19.83°C ). For all sample without water spray, the rise of temperature was exceed 5 °C . In contrast, with water spray, the temperature rise in the pulp can be firmly controlled under 1°C. The results also indicated that ablation rate and efficiency can be enhanced by increasing the incident radiant exposure and pulse repetition rate, which simultaneously producing more heat accumulation in dental tissue and causing thermal damage to dental tissue. By applying an additional water spray, thermal damage can be significantly reduced in clinical application.

Algae-based biofilm productivity utilizing dairy wastewater: effects of temperature and organic carbon concentration.

PubMed

Fica, Zachary T; Sims, Ronald C

2016-01-01

Biofilm-based microalgal growth was determined as functions of organic chemical loading and water temperature utilizing dairy wastewater from a full-scale dairy farm. The dairy industry is a significant source of wastewater worldwide that could provide an inexpensive and nutrient rich feedstock for the cultivation of algae biomass for use in downstream processing of animal feed and aquaculture applications. Algal biomass was cultivated using a Rotating Algal Biofilm Reactor (RABR) system. The RABR is a biofilm-based technology that has been designed and used to remediate municipal wastewater and was applied to treat dairy wastewater through nutrient uptake, and simultaneously provide biomass for the production of renewable bioproducts. Aerial algal biofilm growth rates in dairy wastewater at 7 and 27 °C temperatures were shown to be 4.55 ± 0.17 g/m 2 -day and 7.57 ± 1.12 g/m 2 -day ash free dry weight (AFDW), respectively. Analysis of Variance (ANOVA) calculations indicated that both an increase in temperature of the wastewater and an increase in the level of organic carbon, from 300 to 1200 mg L -1 , contributed significantly to an increase in the rate of biomass growth in the system. However, ANOVA results indicated that the interaction of temperature and organic carbon content was not significantly related to the biofilm-based growth rate. A microalgae-based biofilm reactor was successfully used to treat turbid dairy wastewater. Temperature and organic carbon concentration had a statistically significant effect on algae-based biofilm productivity and treatment of dairy wastewater. The relationships between temperature, TOC, and productivity developed in this study may be used in the design and assessment of wastewater remediation systems and biomass production systems utilizing algae-based biofilm reactors for treating dairy wastes.

Effect of a heat and moisture exchanger on heat loss in isoflurane-anesthetized dogs undergoing single-limb orthopedic procedures.

PubMed

Hofmeister, Erik H; Brainard, Benjamin M; Braun, Christina; Figueiredo, Juliana P

2011-12-15

To determine whether a heat and moisture exchange device (HME) prevents a decrease in body temperature in isoflurane-anesthetized dogs undergoing orthopedic procedures. Blinded randomized controlled clinical trial. 60 privately owned dogs weighing at least 15 kg (33 lb). Dogs were randomly assigned to 1 of 3 treatment groups (n = 20/group): HME placed immediately after anesthetic induction with isoflurane, after transfer to the operating room, or not at all. The device consisted of a hygroscopic filter placed between the endotracheal tube and the Y piece of the anesthesia circuit. Each dog was positioned on a circulating warm water blanket and had a forced-air warming blanket placed over its body. Body temperature was monitored after transfer to the operating room with a probe placed in the thoracic aspect of the esophagus. Study groups did not differ significantly with respect to body weight, body condition score, reproductive status, breed, surgical procedure, preoperative sedative and opioid administration, anesthetic induction drug, local nerve block technique, or operating room assignment. There were no significant differences among groups in esophageal temperature variables, interval between anesthetic induction and surgery, surgery duration, anesthesia duration, or oxygen flow rate. However, the relationship between temperature delta and body weight was significant and relevant (R(2) = 0.23), as was the association between temperature nadir and body weight (R(2)= 0.10). As body weight increased, the temperature delta decreased and temperature nadir increased. No other significant relationships were identified. Inclusion of an HME in healthy dogs undergoing anesthesia for an elective orthopedic surgery did not facilitate maintenance of body temperature throughout the procedure.

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.

Does hot weather affect work-related injury? A case-crossover study in Guangzhou, China.

PubMed

Sheng, Rongrong; Li, Changchang; Wang, Qiong; Yang, Lianping; Bao, Junzhe; Wang, Kaiwen; Ma, Rui; Gao, Chuansi; Lin, Shao; Zhang, Ying; Bi, Peng; Fu, Chuandong; Huang, Cunrui

2018-04-01

Despite increasing concerns about the health effects of climate change, the extent to which workers are affected by hot weather is not well documented. This study aims to investigate the association between high temperatures and work-related injuries using data from a large subtropical city in China. We used workers' compensation claims to identify work-related injuries in Guangzhou, China during 2011-2012. To feature the heat effect, the study period was restricted to the warm seasons in Guangzhou (1 May-31 October). We conducted a time-stratified case-crossover study to examine the association between ambient outdoor temperatures, including daily maximum and minimum temperatures, and cases of work-related injury. The relationships were assessed using conditional Poisson regression models. Overall, a total of 5418 workers' compensation claims were included over the study period. Both maximum and minimum temperatures were significantly associated with work-related injuries, but associations varied by subgroup. One °C increase in maximum temperature was associated with a 1.4% (RR = 1.014, 95%CIs 1.012-1.017) increase in daily injury claims. Significant associations were seen for male and middle-aged workers, workers in small and medium-sized enterprises, and those working in manufacturing sector. And 1 °C increase in minimum temperature was associated with 1.7% (RR = 1.017, 95%CIs 1.012-1.021) increase in daily injury claims. Significant associations were observed for female and middle-aged workers, workers in large-sized enterprises, and those working in transport and construction sectors. We found a higher risk of work-related injuries due to hot weather in Guangzhou, China. This study provides important epidemiological evidence for policy-makers and industry that may assist in the formulation of occupational safety and climate adaptation strategies. Copyright © 2018 Elsevier GmbH. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2012-09-01

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

Effects of stress temperatures of germination on polyamine titers of soybean seeds

NASA Astrophysics Data System (ADS)

Pineda-Mejia, Renan

High and low stress temperatures during seed germination and seedling development limit total germination and the rate of germination and growth. Changes in polyamine (PA) concentrations in seeds of different species have been associated with germination, growth and environmental stresses such as temperature, drought, oxygen, chilling injury and osmotic conditions. Two studies were conducted to determine the effect of stress temperatures during germination and seedling development on polyamine titers in soybean seeds. Three germination temperatures, 25, 30, and 36°C were used in the first study to evaluate their influence on changes in polyamine concentrations in soybean seeds germinated at 76 and 90 hours. The polyamines (PAs), cadaverine (Cad), putrescine (Put), spermidine (Spd), agmatine (Agm), and spermine (Spin) were quantified by HPLC using a cation exchange column and an electrochemical detector. Cad, Put, Agm, and Spd declined as the germination temperatures increased from 25 to 36°C. Conversely, Spin increased considerably with an increase in temperature. Total germination was reduced from 97.2 to 92.5% as germination temperatures increased from 25 to 36°C. Germination time did not affect Cad, Agm and Spm, and total germination, however, the interaction between temperature and germination time for Put and Spd concentrations was significant. In the second study, changes in PA concentrations, seedling growth, germination time (t50), fresh and dry weight, and moisture content were measured in the embryonic axis and cotyledons of soybean seeds germinated at 10 and 25°C through six stages of germination dry seed (DS), testa split (TS), radicle at 10 mm (Ra-10), root hairs visible (RHV), secondary root primordia (SRP), and complete seedling (CS). The concentrations of Cad and Put in the embryonic axis, were significantly higher in seeds germinated under low temperature than in seeds at 25°C (approximately 10 and 3 fold respectively). However, this difference was not observed until the last three stages of germination. The stage of germination also influenced the levels of these polyamines. The concentrations of Cad and Put detected at the CS stage were 50 and 18 fold respectively, relative to the initial concentrations found at the DS stage. Spd levels in seeds under stress temperatures also increased, but to a lesser extent compared to Cad and Put. Differences in Spd concentrations between temperatures were observed only at the CS stage. Agm concentrations were higher at 25 than at 10°C at SRP and CS. Spm concentrations of seeds germinated at 25°C remained higher during the first four stages of development but at the end of germination, seeds at 10°C had higher quantities of Spm. In the cotyledons, Polyamines tended to decline with stages of germination, regardless of the temperature. However, Agm levels increased in the cotyledons of soybean seeds. Maximum dry weight and seedling growth was found at RHV, SRP, and CS. Maximum levels of Cad and Put were also found during these stages. Spd increased with both temperatures from DS to Ra-10, thereafter, Spd levels in seeds at 10°C continued increasing while seeds at 25°C declined. High and low stress germination temperatures caused significant changes in polyamine concentrations, reduced germination and seedling growth of soybean seeds.

The role of Meridional Overturning Circulation (MOC) on Ancient Climates and Implications for Anthropogenic Climate Change

NASA Astrophysics Data System (ADS)

Cumming, M.

2017-12-01

Our increasingly robust history of ancient climates indicates that high latitude glaciation is the ultimate product of an episodic cooling trend that began about 100-million years ago rather than a result of a yet-to-be identified modal change. Antarctic geography (continent surrounded by ocean) allowed ice to develop prior to significant glaciation in the Northern Hemisphere (ocean surrounded by land), but global ice volume generally increased as Earth cooled. The question of what caused the Ice Ages should be reframed as to "What caused the Cenozoic Cooling?" Records tell us that changes in temperature and CO2 levels rise and fall together, however it is not clear when CO2 acts as a driver versus when it is primarily an indicator of temperature change. The episodic nature of the cooling trend suggests other more dynamic phenomena are involved. It is proposed that oceanic meridional overturning circulation (MOC) plays a significant role in regulating Earth's surface temperature. Robust MOC has a cooling effect which results from its sequestration of cold waters (together with their increased heat-absorbing potential) below the surface. Unable to better absorb equatorial insolation for great lengths of time, oceanic deep waters are not able to fully compensate for the heat lost by warm-water transport to Polar Regions. A lag-time between cooling and subsequent warming yields lower operating temperatures commensurate with the strength of global MOC. The long-term decline in global temperatures is largely explained by the tectonic reshaping of ocean basins and the connections between them such that MOC has generally, but not uniformly, increased. Geophysically Influenced MOC (GIMOC) has caused a significant proportion of the lowering of global temperatures in the Cenozoic Era. Short-term disruptions in MOC (and subsequent impacts on global temperatures) were likely involved in Late Pleistocene glacial termination events and may already be compounding present anthropogenic CO2 induced warming.

The effect of temperature changes on electrical performance of the betavoltaic cell.

PubMed

Wang, Guanquan; Hu, Rui; Wei, Hongyuan; Zhang, Huaming; Yang, Yuqing; Xiong, Xiaoling; Liu, Guoping; Luo, Shunzhong

2010-12-01

There is a significant relationship between temperature and electrical performance of a betavoltaic cell. Two silicon diodes used as energy conversion devices of betavoltaic cells were irradiated by Ni-63, and the relationships between the temperature and the electrical performance such as V(oc), I(sc), and P(max) were examined. I(sc) increased very little as temperature increased but V(oc) decreased considerably. The changing values of V(oc) were -3.1 and -3.0 mV/K, respectively, in the temperature range 233.15-333.15 K. As a result of this, P(max) and eta also decreased markedly. Copyright 2010 Elsevier Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2018-03-01

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

Temperature dependence of thermal boundary resistances between multiwalled carbon nanotubes and some typical counterpart materials.

PubMed

Zhang, Guang; Liu, Changhong; Fan, Shoushan

2012-04-24

We directly measured the temperature dependence of thermal boundary resistances (TBRs) between multiwalled carbon nanotubes (MWCNTs) and different materials at elevated temperatures. Using the steady-state heat flow and the noncontacted measurement method, we could conveniently obtain the TBR-temperature relations. Our results indicate that the TBR-temperature relations vary distinctively with different contact materials when heating temperatures change from about 300 to 450 K; that is, the CNT-metal TBRs increase with increasing temperatures, whereas the CNT-insulator TBRs decrease. As a comparison, the TBRs between superaligned MWCNTs were measured and we found that the CNT-CNT TBRs remain basically unchanged as temperatures increase. We also found that the magnitude of TBRs between MWCNTs and different materials could differ from each other significantly. These results suggest that the choice of the right electrode may have an obvious influence on the thermal properties and other properties of the CNT-based devices. From another perspective, in view of some existing theoretical models about TBRs, our results support the validity of the molecular dynamics (MD) simulations in the calculation of CNT-solid TBRs at elevated temperatures.

Temperature-dependent plastic hysteresis in highly confined polycrystalline Nb films

NASA Astrophysics Data System (ADS)

Waheed, S.; Hao, R.; Zheng, Z.; Wheeler, J. M.; Michler, J.; Balint, D. S.; Giuliani, F.

2018-02-01

In this study, the effect of temperature on the cyclic deformation behaviour of a confined polycrystalline Nb film is investigated. Micropillars encapsulating a thin niobium interlayer are deformed under cyclic axial compression at different test temperatures. A distinct plastic hysteresis is observed for samples tested at elevated temperatures, whereas negligible plastic hysteresis is observed for samples tested at room temperature. These results are interpreted using planar discrete dislocation plasticity incorporating slip transmission across grain boundaries. The effect of temperature-dependent grain boundary energy and dislocation mobility on dislocation penetration and, consequently, the size of plastic hysteresis is simulated to correlate with the experimental results. It is found that the decrease in grain boundary energy barrier caused by the increase in temperature does not lead to any appreciable change in the cyclic response. However, dislocation mobility significantly affects the size of plastic hysteresis, with high mobilities leading to a larger hysteresis. Therefore, it is postulated that the experimental observations are predominantly caused by an increase in dislocation mobility as the temperature is increased above the critical temperature of body-centred cubic niobium.

Temperature measurements during high flux ion beam irradiations

DOE PAGES

Crespillo, Miguel L.; Graham, Joseph T.; Zhang, Yanwen; ...

2016-02-16

A systematic study of the ion beam heating effect was performed in a temperature range of –170 to 900 °C using a 10 MeV Au 3+ ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 10 12 cm –2 s –1. Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparisonmore » with numerical calculations suggests that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. Furthermore, a simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beamanalysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect.« less

Effect of light-enhanced bleaching on in vitro surface and intrapulpal temperature rise.

PubMed

Baik, J W; Rueggeberg, F A; Liewehr, F R

2001-01-01

This study investigated the effect of the presence, absence, and aging of a heat-enhancing compound (colorant) added to bleaching gel on the temperature rise of the gel itself, as well as the temperature rise within the pulp chamber, when a tooth was exposed to a variety of light-curing units in vitro. An extracted human upper central incisor was fitted with thermocouples placed in the pulp chamber as well as on the facial tooth surface. A temperature-controlled simulated intrapulpal fluid flow was provided to the tooth, and bleaching agent (Opalesence XTRA, Ultradent) containing heat-enhancing colorant, aged colorant, or no colorant was applied to the facial surface. The tooth and light-curing unit were placed in a thermostatically controlled oven at 37 degrees C, and real-time gel and intrapulpal temperature values were recorded digitally. Light-curing units used were a plasma arc light (PAC) (PowerPac, ADT), a conventional quartz tungsten halogen source (QTH) (Optilux 501, Demetron/Kerr), the QTH light used in high-power (bleaching) mode, and an argon ion laser (AccuCure 3000, LaserMed). An exposure scenario simulating light-enhanced bleaching of 10 upper teeth was developed. Temperature rise over the pre-exposure, baseline value associated with the last light exposure in the bleaching sequence was calculated for each curing and bleaching combination. Five replications for each test condition were made. Temperature rise values were compared using analysis of variance (ANOVA) at a preset alpha of 0.05. When fresh colorant-containing bleach was used, the PAC light increased bleach temperature 39.3 degrees C above baseline. With no added colorant, temperature rise was 37.1 degrees C. The QTH light in bleach mode resulted in gel temperature 24.8 degrees C above baseline, whereas the temperature increase was only 11.5 degrees C when no colorant was used. Conventional QTH light use increased fresh bleach temperature by 17.7 degrees C, whereas an increase of only 11.1 degrees C was measured without colorant. The argon ion laser produced equivalent temperature rise regardless of the presence or freshness of the colorant, approximately 9.4 degrees C. Intrapulpal temperatures were all significantly lower than those recorded in the bleaching gel and ranged from 5 degrees to 8 degrees C. As a rule, the presence of fresh heat-enhancing colorant in the bleaching gel resulted in a significant intrapulpal temperature increase (approximately 1 degrees C) over that reached using other lights. The PAC and the QTH light used in bleach mode induced greater intrapulpal temperature rise than the laser. Freshness of bleaching agent incorporating light-activated, heat-enhancing colorant influences temperature rise of bleaching gel and also may increase intrapulpal temperature values. Use of intense lights does elevate bleach temperature and also results in increased intrapulpal temperature that may further impact on patient sensitivity and pulpal health resulting from this treatment.

Projections of Seasonal Patterns in Temperature- Related Deaths for Manhattan, New York

NASA Technical Reports Server (NTRS)

Li, Tiantian; Horton, Radley M.; Kinney, Patrick L.

2013-01-01

Global average temperatures have been rising for the past half-century, and the warming trend has accelerated in recent decades. Further warming is expected over the next few decades, with significant regional variations. These warming trends will probably result in more frequent, intense and persistent periods of hot temperatures in summer, and generally higher temperatures in winter. Daily death counts in cities increase markedly when temperatures reach levels that are very high relative to what is normal in a given location. Relatively cold temperatures also seem to carry risk. Rising temperatures may result in more heat-related mortality but may also reduce cold-related mortality, and the net impact on annual mortality remains uncertain. Here we use 16 downscaled global climate models and two emissions scenarios to estimate present and future seasonal patterns in temperature-related mortality in Manhattan, New York. All 32 projections yielded warm-season increases and cold-season decreases in temperature-related mortality, with positive net annual temperature-related deaths in all cases. Monthly analyses showed that the largest percentage increases may occur in May and September. These results suggest that, over a range of models and scenarios of future greenhouse gas emissions, increases in heat-related mortality could outweigh reductions in cold-related mortality, with shifting seasonal patterns.

A New Correction Technique for Strain-Gage Measurements Acquired in Transient-Temperature Environments

NASA Technical Reports Server (NTRS)

Richards, W. Lance

1996-01-01

Significant strain-gage errors may exist in measurements acquired in transient-temperature environments if conventional correction methods are applied. As heating or cooling rates increase, temperature gradients between the strain-gage sensor and substrate surface increase proportionally. These temperature gradients introduce strain-measurement errors that are currently neglected in both conventional strain-correction theory and practice. Therefore, the conventional correction theory has been modified to account for these errors. A new experimental method has been developed to correct strain-gage measurements acquired in environments experiencing significant temperature transients. The new correction technique has been demonstrated through a series of tests in which strain measurements were acquired for temperature-rise rates ranging from 1 to greater than 100 degrees F/sec. Strain-gage data from these tests have been corrected with both the new and conventional methods and then compared with an analysis. Results show that, for temperature-rise rates greater than 10 degrees F/sec, the strain measurements corrected with the conventional technique produced strain errors that deviated from analysis by as much as 45 percent, whereas results corrected with the new technique were in good agreement with analytical results.

Warming increases the risk of civil war in Africa.

PubMed

Burke, Marshall B; Miguel, Edward; Satyanath, Shanker; Dykema, John A; Lobell, David B

2009-12-08

Armed conflict within nations has had disastrous humanitarian consequences throughout much of the world. Here we undertake the first comprehensive examination of the potential impact of global climate change on armed conflict in sub-Saharan Africa. We find strong historical linkages between civil war and temperature in Africa, with warmer years leading to significant increases in the likelihood of war. When combined with climate model projections of future temperature trends, this historical response to temperature suggests a roughly 54% increase in armed conflict incidence by 2030, or an additional 393,000 battle deaths if future wars are as deadly as recent wars. Our results suggest an urgent need to reform African governments' and foreign aid donors' policies to deal with rising temperatures.

Design and implementation of temperature and humidity monitoring system for poultry farm

NASA Astrophysics Data System (ADS)

Purnomo, Hindriyanto Dwi; Somya, Ramos; Fibriani, Charitas; Purwoko, Angga; Sadiyah, Ulfa

2016-10-01

Automatic monitoring system gains significant interest in poultry industry due to the need of consistent environment condition. Appropriate environment increase the feed conversion ratio as well as birds productivity. This will increase the competitiveness of the poultry industry. In this research, a temperature and humidity monitoring system is proposed to observer the temperature and relative humidity of a poultry house. The system is intended to be applied in the poultry industry with partnership schema. The proposed system is equipped with CCTV for visual monitoring. The measured temperature and humidity implement wireless sensor network technology. The experiment results reveals that proposed system have the potential to increase the effectiveness of monitoring of poultry house in poultry industry with partnership schema.

High-temperature beverages and Foods and Esophageal Cancer Risk -- A Systematic Review

PubMed Central

Islami, Farhad; Boffetta, Paolo; Ren, JianSong; Pedoeim, Leah; Khatib, Dara; Kamangar, Farin

2009-01-01

Coffee, tea, and maté may cause esophageal cancer (EC) by causing thermal injury to the esophageal mucosa. If so, the risk of EC attributable to thermal injury could be large in populations in which these beverages are commonly consumed. In addition, these drinks may cause or prevent EC via their chemical constituents. Therefore, a large number of epidemiologic studies have investigated the association of an indicator of amount or temperature of use of these drinks or other hot foods and beverages with risk of EC. We conducted a systematic review of these studies, and report the results for amount and temperature of use separately. By searching PubMed and the ISI, we found 59 eligible studies. For coffee and tea, there was little evidence for an association between amount of use and EC risk; however, the majority of studies showed an increased risk of EC associated with higher drinking temperature which was statistically significant in most of them. For maté drinking, the number of studies was limited, but they consistently showed that EC risk increased with both amount consumed and temperature, and these two were independent risk factors. For other hot foods and drinks, over half of the studies showed statistically significant increased risks of EC associated with higher temperature of intake. Overall, the available results strongly suggest that high-temperature beverage drinking increases the risk of EC. Future studies will require standardized strategies that allow for combining data, and results should be reported by histological subtypes of EC. PMID:19415743

Increasing influence of heat stress on French maize yields from the 1960s to the 2030s

PubMed Central

Hawkins, Ed; Fricker, Thomas E; Challinor, Andrew J; Ferro, Christopher A T; Kit Ho, Chun; Osborne, Tom M

2013-01-01

Improved crop yield forecasts could enable more effective adaptation to climate variability and change. Here, we explore how to combine historical observations of crop yields and weather with climate model simulations to produce crop yield projections for decision relevant timescales. Firstly, the effects on historical crop yields of improved technology, precipitation and daily maximum temperatures are modelled empirically, accounting for a nonlinear technology trend and interactions between temperature and precipitation, and applied specifically for a case study of maize in France. The relative importance of precipitation variability for maize yields in France has decreased significantly since the 1960s, likely due to increased irrigation. In addition, heat stress is found to be as important for yield as precipitation since around 2000. A significant reduction in maize yield is found for each day with a maximum temperature above 32 °C, in broad agreement with previous estimates. The recent increase in such hot days has likely contributed to the observed yield stagnation. Furthermore, a general method for producing near-term crop yield projections, based on climate model simulations, is developed and utilized. We use projections of future daily maximum temperatures to assess the likely change in yields due to variations in climate. Importantly, we calibrate the climate model projections using observed data to ensure both reliable temperature mean and daily variability characteristics, and demonstrate that these methods work using retrospective predictions. We conclude that, to offset the projected increased daily maximum temperatures over France, improved technology will need to increase base level yields by 12% to be confident about maintaining current levels of yield for the period 2016–2035; the current rate of yield technology increase is not sufficient to meet this target. PMID:23504849

The 12-day thermoregulatory metamorphosis of Red-winged Blackbirds (Agelaius phoeniceus).

PubMed

Sirsat, Sarah K Goy; Sirsat, Tushar S; Crossley, Janna L; Sotherland, Paul R; Dzialowski, Edward M

2016-07-01

We examined development of endothermy in altricial Red-winged Blackbirds (Agelaius phoeniceus) by measuring oxygen consumption [Formula: see text], body temperature and ventilation at ambient temperatures from 35 to 15 °C. Mitochondrial respiration of permeabilized skeletal muscle was also measured from breast (pectoralis) and thigh (femorotibialis) muscles. Animals were studied from the first day of hatching through fledging (12 days post-hatch, dph). Nestling whole-body metabolic rate began to show an endothermic response to cold temperature midway between hatching and fledging. Nestlings less than 5 dph were unable to maintain elevated [Formula: see text] and body temperature when exposed to gradually decreasing temperature, whereas 7 dph nestlings maintained [Formula: see text] until ~25 °C, after which [Formula: see text] decreased. From 10 dph to fledging, animals maintained elevated [Formula: see text] and body temperature when exposed to gradual cooling; full endothermic capacity was achieved. Ventilation followed a similar developmental trend to that of [Formula: see text], with increases in 10 dph fledglings occurring in tidal volume rather than ventilation frequency. LEAK respiration and oxidative phosphorylation (OXPHOS) through complex I of breast muscle mitochondria increased significantly after 3 dph. Expression of avUCP and PCG-1α mRNA increased significantly at 3 dph and remained elevated in both skeletal muscle types. Increased metabolic capacity at the cellular level occurred prior to that of the whole animal. This change in whole animal metabolic capacity increased steadily upon hatching as evidenced by the shift of metabolic rate from an ectothermic to endothermic phenotype and the increase of mitochondrial OXPHOS activity of the shivering muscles of this altricial avian species.

Finite-temperature H behaviors in tungsten and molybdenum: first-principles total energy and vibration spectrum calculations

NASA Astrophysics Data System (ADS)

Liu, Yue-Lin; Ding, Fang; Luo, G.-N.; Chen, Chang-An

2017-12-01

We have carried out systematic first-principles total energy and vibration spectrum calculations to investigate the finite-temperature H dissolution behaviors in tungsten and molybdenum, which are considered promising candidates for the first wall in nuclear fusion reactors. The temperature effect is considered by the lattice expansion and phonon vibration. We demonstrate that the H Gibbs energy of formation in both tetrahedral and octahedral interstitial positions depends strongly on the temperature. The H Gibbs energy of formation under one atmosphere of pressure increases significantly with increasing temperature. The phonon vibration contribution plays a decisive role in the H Gibbs energy of formation with the increasing temperature. Using the predicted H Gibbs energy of formation, our calculated H concentrations in both metals are about one or two orders of magnitude lower than the experimental data at temperature range from 900 to 2400 K. Such a discrepancy can be reasonably explained by the defect-capturing effect.

Temperature-dependent elimination efficiency on Phaeocystis globosa by different initial population sizes of rotifer Brachionus plicatilis.

PubMed

Sun, Yunfei; Wang, Yuanyuan; Lei, Jin; Qian, Chenchen; Zhu, Xuexia; Akbar, Siddiq; Huang, Yuan; Yang, Zhou

2018-07-01

Due to sea water eutrophication and global warming, the harmful Phaeocystis blooms outbreak frequently in coastal waters, which cause a serious threat to marine ecosystem. The application of rotifer to control the harmful alga is a promising way. To investigate the influence of initial rotifer density and temperature on the ability of rotifer Brachionus plicatilis to eliminate Phaeocystis globosa population, we cultured P. globosa with different initial rotifer densities (1, 3, 5 inds mL -1 ) at 19, 22, 25, 28, and 31 °C for 9-16 d. Results showed that the population of rotifer feeding on Phaeocystis increased rapidly and higher temperatures favored the growth of P. globosa and B. plicatilis. With increased initial rotifer density and temperature, both the clearance rate of rotifer and the reduction rate of P. globosa increased, and thus P. globosa were eliminated earlier. Both temperature and initial rotifer density had significant effects on clearance rate of rotifer and the time to Phaeocystis extinction, and there was a significant interaction between the two factors on the two parameters, i.e., the effect of initial rotifer density on eliminating Phaeocystis decreased with increasing temperature. The rotifer in 5 inds mL -1 at 28 °C eliminated P. globosa in 4 d, whereas the rotifer in 1 ind mL -1 at 19 °C spent about 16 d on eliminating P. globosa. In conclusion, higher temperature and bigger initial rotifer density promote rotifer to eliminate the harmful P. globosa, and the optimal temperature for rotifer to clear P. globosa is 28 °C. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

PubMed

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

2007-06-01

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

Ocean warming increases threat of invasive species in a marine fouling community.

PubMed

Sorte, Cascade J B; Williams, Susan L; Zerebecki, Robyn A

2010-08-01

We addressed the potential for climate change to facilitate invasions and precipitate shifts in community composition by testing effects of ocean warming on species in a marine fouling community in Bodega Harbor, Bodega Bay, California, USA. First, we determined that introduced species tolerated significantly higher temperatures than natives, suggesting that climate change will have a disproportionately negative impact on native species. Second, we assessed the temperature dependence of survival and growth by exposing juveniles to an ambient control temperature and increased temperatures predicted by ocean warming scenarios (+3 degrees C and +4.5 degrees C) in laboratory mesocosms. We found that responses differed between species, species origins, and demographic processes. Based on the temperature tolerance, survival, and growth results, we predict that, as ocean temperatures increase, native species will decrease in abundance, whereas introduced species are likely to increase in this system. Facilitation of invasions by climate change may already be underway; locally, invasive dominance has increased concurrent with ocean warming over the past approximately 40 years. We suggest that the effects of climate change on communities can occur via both direct impacts on the diversity and abundance of native species and indirect effects due to increased dominance of introduced species.

Preliminary Study of a Hybrid Helicon-ECR Plasma Source

NASA Astrophysics Data System (ADS)

M. Hala, A.; Oksuz, L.; Ximing, Zhu

2016-08-01

A new type of hybrid discharge is experimentally investigated in this work. A helicon source and an electron cyclotron resonance (ECR) source were combined to produce plasma. As a preliminary study of this type of plasma, the optical emission spectroscopy (OES) method was used to obtain values of electron temperature and density under a series of typical conditions. Generally, it was observed that the electron temperature decreases and the electron density increases as the pressure increased. When increasing the applied power at a certain pressure, the average electron density at certain positions in the discharge does not increase significantly possibly due to the high degree of neutral depletion. Electron temperature increased with power in the hybrid mode. Possible mechanisms of these preliminary observations are discussed.

Plastic Responses Contribute to Explaining Altitudinal and Temporal Variation in Potential Flower Longevity in High Andean Rhodolirion montanum.

PubMed

Pacheco, Diego Andrés; Dudley, Leah S; Cabezas, Josefina; Cavieres, Lohengrin A; Arroyo, Mary T K

2016-01-01

The tendency for flower longevity to increase with altitude is believed by many alpine ecologists to play an important role in compensating for low pollination rates at high altitudes due to cold and variable weather conditions. However, current studies documenting an altitudinal increase in flower longevity in the alpine habitat derive principally from studies on open-pollinated flowers where lower pollinator visitation rates at higher altitudes will tend to lead to flower senescence later in the life-span of a flower in comparison with lower altitudes, and thus could confound the real altitudinal pattern in a species´ potential flower longevity. In a two-year study we tested the hypothesis that a plastic effect of temperature on flower longevity could contribute to an altitudinal increase in potential flower longevity measured in pollinator-excluded flowers in high Andean Rhodolirium montanum Phil. (Amaryllidaceae). Using supplemental warming we investigated whether temperature around flowers plastically affects potential flower longevity. We determined tightly temperature-controlled potential flower longevity and flower height for natural populations on three alpine sites spread over an altitudinal transect from 2350 and 3075 m a.s.l. An experimental increase of 3.1°C around flowers significantly decreased flower longevity indicating a plastic response of flowers to temperature. Flower height in natural populations decreased significantly with altitude. Although temperature negatively affects flower longevity under experimental conditions, we found no evidence that temperature around flowers explains site variation in flower longevity over the altitudinal gradient. In a wetter year, despite a 3.5°C temperature difference around flowers at the extremes of the altitudinal range, flower longevity showed no increase with altitude. However, in a drier year, flower longevity increased significantly with altitude. The emerging picture suggests an increase in flower longevity along the altitudinal gradient is less common for potential flower longevity than for open-pollination flower longevity. Independently of any selection that may occur on potential longevity, plastic responses of flowers to environmental conditions are likely to contribute to altitudinal variation in flower longevity, especially in dry alpine areas. Such plastic responses could push flowers of alpine species towards shorter life-lengths under climate change, with uncertain consequences for successful pollination and plant fitness in a warming world.

Plastic Responses Contribute to Explaining Altitudinal and Temporal Variation in Potential Flower Longevity in High Andean Rhodolirion montanum

PubMed Central

Cavieres, Lohengrin A.

2016-01-01

The tendency for flower longevity to increase with altitude is believed by many alpine ecologists to play an important role in compensating for low pollination rates at high altitudes due to cold and variable weather conditions. However, current studies documenting an altitudinal increase in flower longevity in the alpine habitat derive principally from studies on open-pollinated flowers where lower pollinator visitation rates at higher altitudes will tend to lead to flower senescence later in the life-span of a flower in comparison with lower altitudes, and thus could confound the real altitudinal pattern in a species´ potential flower longevity. In a two-year study we tested the hypothesis that a plastic effect of temperature on flower longevity could contribute to an altitudinal increase in potential flower longevity measured in pollinator-excluded flowers in high Andean Rhodolirium montanum Phil. (Amaryllidaceae). Using supplemental warming we investigated whether temperature around flowers plastically affects potential flower longevity. We determined tightly temperature-controlled potential flower longevity and flower height for natural populations on three alpine sites spread over an altitudinal transect from 2350 and 3075 m a.s.l. An experimental increase of 3.1°C around flowers significantly decreased flower longevity indicating a plastic response of flowers to temperature. Flower height in natural populations decreased significantly with altitude. Although temperature negatively affects flower longevity under experimental conditions, we found no evidence that temperature around flowers explains site variation in flower longevity over the altitudinal gradient. In a wetter year, despite a 3.5°C temperature difference around flowers at the extremes of the altitudinal range, flower longevity showed no increase with altitude. However, in a drier year, flower longevity increased significantly with altitude. The emerging picture suggests an increase in flower longevity along the altitudinal gradient is less common for potential flower longevity than for open-pollination flower longevity. Independently of any selection that may occur on potential longevity, plastic responses of flowers to environmental conditions are likely to contribute to altitudinal variation in flower longevity, especially in dry alpine areas. Such plastic responses could push flowers of alpine species towards shorter life-lengths under climate change, with uncertain consequences for successful pollination and plant fitness in a warming world. PMID:27861586

Plasmaspheric H+, He+, O+, He++, and O++ Densities and Temperatures

NASA Technical Reports Server (NTRS)

Gallagher, D. L.; Craven, P. D.; Comfort H.

2013-01-01

Thermal plasmaspheric densities and temperatures for five ion species have recently become available, even though these quantities were derived some time ago from the Retarding Ion Mass Spectrometer onboard the Dynamics Explorer 1 satellite over the years 1981-1984. The quantitative properties will be presented. Densities are found to have one behavior with lessor statistical variation below about L=2 and another with much greater variability above that Lshell. Temperatures also have a behavior difference between low and higher L-values. The density ratio He++/H+ is the best behaved with values of about 0.2% that slightly increase with increasing L. Unlike the He+/H+ density ratio that on average decreases with increasing Lvalue, the O+/H+ and O++/H+ density ratios have decreasing values below about L=2 and increasing average ratios at higher L-values. Hydrogen ion temperatures range from about 0.2 eV to several 10s of eV for a few measurements, although the bulk of the observations are of temperatures below 3 eV, again increasing with L-value. The temperature ratios of He+/H+ are tightly ordered around 1.0 except for the middle plasmasphere between L=3.5 and 4.5 where He+ temperatures can be significantly higher. The temperatures of He++, O+, and O++ are consistently higher than H+.

Plasmaspheric H+, He+, He++, O+, and O++ Densities and Temperatures

NASA Technical Reports Server (NTRS)

Gallagher, G. L.; Craven, P. D.; Comfort, R. H.

2013-01-01

Thermal plasmaspheric densities and temperatures for five ion species have recently become available, even though these quantities were derived some time ago from the Retarding Ion Mass Spectrometer onboard the Dynamics Explorer 1 satellite over the years 1981-1984. The quantitative properties will be presented. Densities are found to have one behavior with lessor statistical variation below about L=2 and another with much greater variability above that Lshell. Temperatures also have a behavior difference between low and higher L-values. The density ratio He++/H+ is the best behaved with values of about 0.2% that slightly increase with increasing L. Unlike the He+/H+ density ratio that on average decreases with increasing Lvalue, the O+/H+ and O++/H+ density ratios have decreasing values below about L=2 and increasing average ratios at higher L-values. Hydrogen ion temperatures range from about 0.2 eV to several 10s of eV for a few measurements, although the bulk of the observations are of temperatures below 3 eV, again increasing with L-value. The temperature ratios of He+/H+ are tightly ordered around 1.0 except for the middle plasmasphere between L=3.5 and 4.5 where He+ temperatures can be significantly higher. The temperatures of He++, O+, and O++ are consistently higher than H+.

Cathinone increases body temperature, enhances locomotor activity, and induces striatal c-fos expression in the Siberian hamster.

PubMed

Jones, S; Fileccia, E L; Murphy, M; Fowler, M J; King, M V; Shortall, S E; Wigmore, P M; Green, A R; Fone, K C F; Ebling, F J P

2014-01-24

Cathinone is a β-keto alkaloid that is the major active constituent of khat, the leaf of the Catha edulis plant that is chewed recreationally in East Africa and the Middle East. Related compounds, such as methcathinone and mephedrone have been increasing in popularity as recreational drugs, resulting in the recent proposal to classify khat as a Class C drug in the UK. There is still limited knowledge of the pharmacological effects of cathinone. This study examined the acute effects of cathinone on core body temperature, locomotor and other behaviors, and neuronal activity in Siberian hamsters. Adult male hamsters, previously implanted with radio telemetry devices, were treated with cathinone (2 or 5mg/kg i.p.), the behavioral profile scored and core body temperature and locomotor activity recorded by radio telemetry. At the end of the study, hamsters received vehicle or cathinone (5mg/kg) and neuronal activation in the brain was determined using immunohistochemical evaluation of c-fos expression. Cathinone dose-dependently induced significant (p<0.0001) increases in both temperature and locomotor activity lasting 60-90min. Cathinone (2mg/kg) increased rearing (p<0.02), and 5mg/kg increased both rearing (p<0.001) and lateral head twitches (p<0.02). Both cathinone doses decreased the time spent at rest (p<0.001). The number of c-fos immunopositive cells were significantly increased in the striatum (p<0.0001) and suprachiasmatic nucleus (p<0.05) following cathinone, indicating increased neuronal activity. There was no effect of cathinone on food intake or body weight. It is concluded that systemic administration of cathinone induces significant behavioral changes and CNS activation in the hamster. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Decadal increase in seagrass biomass and temperature at the CARICOMP site in Bocas del Toro, Panama.

PubMed

López-Calderón, Jorge M; Guzmán, Hector M; Jácome, Gabriel E; Barnes, Penélope A G

2013-12-01

The Caribbean Coastal Marine Productivity Program (CARICOMP) was launched in 1993 to study regional long-term interactions between land and sea, taking standardized measurements of productivity and biomass of mangroves, coral reefs and seagrasses. Since 1999 continuous measurements of seagrass (Thalassia testudinum) parameters as well as environmental data have been recorded in Caribbean Panama. Replicate stations were selected near the Smithsonian Tropical Research Institute in Bocas del Toro. Sediment cores and quadrants were placed there to estimate biomass and productivity, respectively. Mean values for productivity, standing crop, turnover rate, total dry biomass, and Leaf Area Index were 1.74 gDW/m2/d, 66.6 gDW/m2, 2.62%/d, 1481 gDW/m2, and 4.65, respectively. Total dry biomass (shoots, rhizomes and roots) and LAI of T. testudinum increased significantly during the study period. Mean values for total rainfall, Secchi disk depth, sea surface temperature, and salinity were 3498 mm, 8.24 m, 28.79 degrees C, and 32.26 psu, respectively. Sea surface temperature was the only environmental variable with a statistically significant change, increasing from 1999 to 2010. Correlation between sea surface temperature and 7 testudinum parameters (total biomass and LAI) were both positive and significant. Human population has increased dramatically over the last ten years in Bocas del Toro region, increasing pressure (deforestation, runoff, wastewater) over coastal ecosystems (seagrasses, mangroves, coral reefs). Change in the abundance of 7 testudinum may be linked to ocean warming, as a consequence to satisfy plant's metabolic requirements, although other local factors need to be analyzed (reduced grazing and increased eutrophication). A further warming of the ocean could have a negative effect on T. testudinum population, increasing respiratory demands and microbial metabolism.

Effect of pre-drilling on intraosseous temperature during self-drilling mini-implant placement in a porcine mandible model.

PubMed

Gurdán, Zsuzsanna; Vajta, László; Tóth, Ákos; Lempel, Edina; Joób-Fancsaly, Árpád; Szalma, József

2017-03-31

This in vitro study investigated intraos seous heat production during insertion, with and without pre-drilling, of a self-drilling orthodontic mini-implant. To measure temperature changes and drilling times in pig ribs, a special testing apparatus was used to examine new and worn pre-drills at different speeds. Temperatures were measured during mini-implant placement with and without pre-drilling. The average intraosseous temperature increase during manual mini-implant insertion was similar with and without pre-drilling (11.8 ± 2.1°C vs. 11.3 ± 2.4°C, respectively; P = 0.707). During pre-drilling the mean temperature increase for new drills was 2.1°C at 100 rpm, 2.3°C at 200 rpm, and 7.6°C at 1,200 rpm. Temperature increases were significantly higher for worn drills at the same speeds (2.98°C, 3.0°C, and 12.3°C, respectively), while bone temperatures at 100 and 200 rpm were similar for new and worn drills (P = 0.345 and 0.736, respectively). Baseline bone temperature was approximated within 30 s after drilling in most specimens. Drilling time at 100 rpm was 2.1 ± 0.9 s, but was significantly shorter at 200 rpm (1.1 ± 0.2 s) and 1,200 rpm (0.1 ± 0.03 s). Pre-drilling did not decrease intraosseous temperatures. In patients for whom pre-drilling is indicated, speeds of 100 or 200 rpm are recommended, at least 30 s after pilot drilling.

Phase field study of surface-induced melting and solidification from a nanovoid: Effect of dimensionless width of void surface and void size

NASA Astrophysics Data System (ADS)

Basak, Anup; Levitas, Valery I.

2018-05-01

The size effect and the effects of a finite-width surface on barrierless transformations between the solid (S), surface melt (SM), and melt (M) from a spherical nanovoid are studied using a phase field approach. Melting (SM → M and S → M) from the nanovoid occurs at temperatures which are significantly greater than the solid-melt equilibrium temperature θe but well below the critical temperature for solid instability. The relationships between the SM and M temperatures and the ratio of the void surface width and width of the solid-melt interface, Δ ¯ , are found for the nanovoids of different sizes. Below a critical ratio Δ¯ * , the melting occurs via SM and the melting temperature slightly reduces with an increase in Δ ¯ . Both S → SM and SM → M transformations have a jump-like character (excluding the case with the sharp void surface), causing small temperature hysteresis. However, the solid melts without SM for Δ ¯>Δ¯ * , and the melting temperature significantly increases with increasing Δ ¯ . The results for a nanovoid are compared with the melting/solidification of a nanoparticle, for which the melting temperatures, in contrast, are much lower than θe. A linear dependency of the melting temperatures with the inverse of the void radius is shown. The present study shows an unexplored way to control the melting from nanovoids by controlling the void size and the width and energy of the surface.

Risky Adaptation: The Effect of Temperature Extremes on HIV Prevalence

NASA Astrophysics Data System (ADS)

Baker, R.

2016-12-01

Previous work has linked rainfall shock to an increase in HIV prevalence in Sub-Saharan Africa. In this paper we take advantage of repeated waves of the Demographic and Health Survey (DHS) and a new high resolution climate dataset for the African continent to test the non-linear relationship between temperature and HIV. We find a strong and significant relationship between recent high temperatures and increases in HIV prevalence in a region. We then test the effect of temperature on risk factors that may contribute to this increase. High temperatures are linked to an increase in sexual violence, number of partners and a decrease in condom usage - all of which may contribute to the uptake in HIV rate. This paper contributes to the literature on adaptation from two standpoints. First, we suggest that some behavioral changes that are classed as adaptations, in the sense that they allow for consumption smoothing in the face of extreme temperatures, may carry unexpected risks to the individuals involved. Second, we find preliminary evidence that the relationship between temperature and these risky behaviors is diminished in regions prone to higher temperatures, suggesting some adaptation is possible in the long run.

Climate-driven changes in grassland vegetation, snow cover, and lake water of the Qinghai Lake basin

NASA Astrophysics Data System (ADS)

Wang, Xuelu; Liang, Tiangang; Xie, Hongjie; Huang, Xiaodong; Lin, Huilong

2016-07-01

Qinghai Lake basin and the lake have undergone significant changes in recent decades. We examine MODIS-derived grassland vegetation and snow cover of the Qinghai Lake basin and their relations with climate parameters during 2001 to 2010. Results show: (1) temperature and precipitation of the Qinghai Lake basin increased while evaporation decreased; (2) most of the grassland areas improved due to increased temperature and growing season precipitation; (3) weak relations between snow cover and precipitation/vegetation; (4) a significantly negative correlation between lake area and temperature (r=-0.9, p<0.05) and (5) a positive relation between lake level (lake-level difference) and temperature (precipitation). Compared with Namco Lake (located in the inner Tibetan Plateau) where the primary water source of lake level increases was the accelerated melt of glacier/perennial snow cover in the lake basin, for the Qinghai Lake, however, it was the increased precipitation. Increased precipitation explained the improvement of vegetation cover in the Qinghai Lake basin, while accelerated melt of glacier/perennial snow cover was responsible for the degradation of vegetation cover in Namco Lake basin. These results suggest different responses to the similar warming climate: improved (degraded) ecological condition and productive capacity of the Qinghai Lake basin (Namco Lake basin).

Simulation of the process kinetics and analysis of physicochemical properties in the freeze drying of kale

NASA Astrophysics Data System (ADS)

Dziki, Dariusz; Polak, Renata; Rudy, Stanisław; Krzykowski, Andrzej; Gawlik-Dziki, Urszula; Różyło, Renata; Miś, Antoni; Combrzyński, Maciej

2018-01-01

Investigations were performed to study the freeze-drying process of kale (Brassica oleracea L. var acephala). The process of freeze-drying was performed at temperatures of 20, 40, and 60°C for whole pieces of leaves and for pulped leaves. The kinetics of the freeze-drying of both kale leaves and kale pulp were best described by the Page model. The increasing freeze-drying temperature from 20 to 60°C induced an approximately two-fold decrease in the drying time. Freeze-drying significantly increased the value of the lightness, delta Chroma, and browning index of kale, and had little influence on the hue angle. The highest increase in the lightness and delta Chroma was observed for whole leaves freeze-dried at 20°C. An increase in the drying temperature brought about a slight decrease in the lightness, delta Chroma and the total colour difference. Pulping decreased the lightness and hue angle, and increased browning index. Freeze-drying engendered a slight decrease in the total phenolics content and antioxidant activity, in comparison to fresh leaves. The temperature of the process and pulping had little influence on the total phenolics content and antioxidant activity of dried kale, but significantly decreased the contents of chlorophyll a and chlorophyll b.

Direct spectroscopic evidence for competition between thermal molecular agitation and magnetic field in a tetrameric protein in aqueous solution

NASA Astrophysics Data System (ADS)

Calabrò, Emanuele; Magazù, Salvatore

2018-05-01

Samples of a typical tetrameric protein, the hemoglobin, at the concentration of 150 mg/ml in bidistilled water solution, were exposed to a uniform magnetic field at 200 mT at different temperatures of 15∘C, 40∘C and 65∘C. Fourier Transform Infrared Spectroscopy was used to analyze the response of the secondary structure of the protein to both stress agents, heating and static magnetic field. The most relevant result which was observed was the significant increasing in intensity of the Amide I band after exposure to the uniform magnetic field at the room temperature of 15∘C. This result can be explained assuming that protein's α-helices aligned along the direction of the applied magnetic field due to their large dipole moment, inducing the alignment of the entire protein. Increasing of temperature up to 40∘C and 65∘C induced a significant reduction of the increasing in intensity of the Amide I band. This effect may be easily explained assuming that Brownian motion of the protein in water solution caused by thermal molecular agitation increased with increasing of temperature, contrasting the effect of the torque of the magnetic field applied to the protein in water solution.

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

Multiple stress effects on marine planktonic organisms: Influence of temperature on the toxicity of polycyclic aromatic hydrocarbons to Tetraselmis chuii

NASA Astrophysics Data System (ADS)

Vieira, L. R.; Guilhermino, L.

2012-08-01

In the present context of global warming and increasing long-range transport of oil and goods by sea potentially resulting in oil spills, more knowledge on the toxicological interactions between temperature and oil components on marine organisms is urgently needed. Therefore, the effects of temperature increase on the toxicity of three polycyclic aromatic hydrocarbons (PAH; anthracene, phenanthrene and naphthalene) to the marine planktonic algae Tetraselmis chuii were investigated under laboratory conditions. T. chuii cultures were exposed for 96 h to different concentrations of each of the test substances at both 20 and 25 °C. Effect criterion was the inhibition of culture growth assessed at 24 h intervals. All the PAHs significantly reduced T. chuii growth after 96 h of exposure with 20% inhibition concentrations between 0.052 and 1.124 mg L- 1 at 20 °C, and between 0.048 and 0.831 mg L- 1 at 25 °C. At both temperatures, the ranking, in order of decreasing toxicity based on the 50% inhibition concentration, was phenanthrene > naphthalene > anthracene. The increase of temperature by 5 °C significantly increased the toxicity of all the PAHs tested. These findings highlight the importance of considering temperature variation in the ecological risk assessment of oil and other chemical spills in the marine environment, and the need of more research on the toxic effects of multiple stressors on marine organisms.

Miocene vegetation shift and climate change: Evidence from the Siwalik of Nepal

NASA Astrophysics Data System (ADS)

Srivastava, Gaurav; Paudayal, Khum N.; Utescher, Torsten; Mehrotra, R. C.

2018-02-01

We reconstruct climate and vegetation applying the Coexistence Approach (CA) methodology on two palaeofloras recovered from the Lower (middle Miocene; 13-11 Ma) and Middle Siwalik (late Miocene; 9.5-6.8 Ma) sediments of Surai Khola section, Nepal. The reconstructed mean annual temperature (MAT) and cold month mean temperature (CMT) show an increasing trend, while warm month mean temperature (WMT) remains nearly the same during the period. The reconstructed precipitation data indicates that the summer monsoon precipitation was nearly the same during the middle and late Miocene, while the winter season precipitation significantly decreased in the late Miocene. The overall precipitation infers increased rainfall seasonality during the late Miocene. The vegetation during the middle Miocene was dominated by wet evergreen taxa, whereas deciduous ones increased significantly during the late Miocene. The reconstructed climate data indicates that high temperature and significantly low precipitation during the winter season (dry season) in the late Miocene might have enhanced forest fire which favoured the expansion of C4 plants over C3 plants during the period. This idea gets further support not only from a recent forest fire in northern India that was caused by the weakening of winter precipitation, but also from the burnt wood recovered from the late Miocene Siwalik sediments of northern India.

Effects of season on sleep and skin temperature in the elderly

NASA Astrophysics Data System (ADS)

Okamoto-Mizuno, Kazue; Tsuzuki, Kazuyo

2010-07-01

The effects of season on sleep and skin temperature (Tsk) in 19 healthy, elderly volunteers were investigated. Measurements were obtained in summer, winter, and fall, and activity levels were monitored using a wrist actigraph system for five consecutive days. The temperature and humidity of the bedrooms of the subjects’ homes were measured continuously for five days. During actigraphic measurement, Tsk during sleep was measured for two nights. The bedroom temperature and humidity significantly increased in summer compared to winter and fall. In summer, the total sleep time decreased (mean ± SE min; summer, 350.8 ± 15.7; winter, 426.5 ± 14.2; fall, 403.2 ± 16.4) and wakefulness increased ( P < 0.003) compared to those in fall or winter. The sleep efficiency index that was derived from wrist actigraphy was significantly decreased ( P < 0.001) in summer (81.4 ± 2.9%) compared with winter (91.6 ± 1.3%) or fall (90.2 ± 1.2%). The forehead Tsk significantly increased, while the chest and thigh Tsks were decreased in summer compared to those in fall or winter. These results suggest that, in the elderly, sleep is disturbed in summer more than in other seasons, and that this disturbance is related to fluctuations in Tsk.

Physiological responses and manual performance in humans following repeated exposure to severe cold at night.

PubMed

Ozaki, H; Nagai, Y; Tochihara, Y

2001-04-01

We evaluated human physiological responses and the performance of manual tasks during exposure to severe cold (-25 degrees C) at night (0300-0500 hours) and in the afternoon (1500-1700 hours). Thirteen male students wearing standard cold protective clothing occupied a severely cold room (-25 degrees C) for 20 min, and were then transferred to a cool room (10 degrees C) for 20 min. This pattern of exposure was repeated three times, for a total time of exposure to extreme cold of 60 min. The experiments were started either at 1500 hours or 0300 hours and measurements of rectal temperature, skin temperature, blood pressure, performance in a counting task, hand tremor, and subjective responses were made in each condition. At the end of the experiment at night the mean decrease in rectal temperature [0.68 (SEM 0.04) degree C] was significantly greater than that at the end of the experiment in the afternoon [0.55 (SEM 0.08) degree C, P < 0.01]. After the second cold exposure at night the mean increase in diastolic blood pressure [90 (SEM 2.0) mmHg] was significantly greater than that at the end of the second cold exposure in the afternoon [82 (SEM 2.8) mmHg, P < 0.01]. At the end of the second cold exposure at night, mean finger skin temperature [11.8 (SEM 0.8) degrees C] was significantly higher than that at the comparable time in the afternoon [9.0 (SEM 0.7) degrees C, P < 0.01]. Similarly for the toe, mean skin temperature at the start of the second cold exposure at night [25.6 (SEM 1.5) degrees C] was significantly higher than in the afternoon [20.1 (SEM 0.8) degrees C, P < 0.01]. The increased skin temperatures in the periphery resulted in increased heat loss. Since peripheral skin temperatures were highest at night, the subjects noted diminished sensations of thermal cold and pain at that time. Manual dexterity at the end of the first cold exposure at night [mean 83.7 (SEM 3.6) times.min-1] had decreased significantly more than at the end of the first cold exposure in the afternoon [mean 89.4 (SEM 3.5) times.min-1, P < 0.01]. These findings of a lowered rectal temperature and diminished manual dexterity suggest that there is an increased risk of both hypothermia and accidents for those who work at night.

Effect of basic alkali-pickling conditions on the production of lysinoalanine in preserved eggs.

PubMed

Zhao, Yan; Luo, Xuying; Li, Jianke; Xu, Mingsheng; Tu, Yonggang

2015-09-01

During the pickling process, strong alkali causes significant lysinoalanine (LAL) formation in preserved eggs, which may reduce the nutritional value of the proteins and result in a potential hazard to human health. In this study, the impacts of the alkali treatment conditions on the production of LAL in preserved eggs were investigated. Preserved eggs were prepared using different times and temperatures, and alkali-pickling solutions with different types and concentrations of alkali and metal salts, and the corresponding LAL contents were measured. The results showed the following: during the pickling period of the preserved egg, the content of LAL in the egg white first rapidly increased and then slowly increased; the content of LAL in the egg yolk continued to increase significantly. During the aging period, the levels of LAL in both egg white and egg yolk slowly increased. The amounts of LAL in the preserved eggs were not significantly different at temperatures between 20 and 25ºC. At higher pickling temperatures, the LAL content in the preserved eggs increased. With the increase of alkali concentration in the alkali-pickling solution, the LAL content in the egg white and egg yolk showed an overall trend of an initial increase followed by a slight decrease. The content of LAL produced in preserved eggs treated with KOH was lower than in those treated with NaOH. NaCl and KCl produced no significant effects on the production of LAL in the preserved eggs. With increasing amounts of heavy metal salts, the LAL content in the preserved eggs first decreased and then increased. The LAL content generated in the CuSO4 group was lower than that in either the ZnSO4 or PbO groups. © 2015 Poultry Science Association Inc.

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

Ocean warming since 1982 has expanded the niche of toxic algal blooms in the North Atlantic and North Pacific oceans.

PubMed

Gobler, Christopher J; Doherty, Owen M; Hattenrath-Lehmann, Theresa K; Griffith, Andrew W; Kang, Yoonja; Litaker, R Wayne

2017-05-09

Global ocean temperatures are rising, yet the impacts of such changes on harmful algal blooms (HABs) are not fully understood. Here we used high-resolution sea-surface temperature records (1982 to 2016) and temperature-dependent growth rates of two algae that produce potent biotoxins, Alexandrium fundyense and Dinophysis acuminata , to evaluate recent changes in these HABs. For both species, potential mean annual growth rates and duration of bloom seasons significantly increased within many coastal Atlantic regions between 40°N and 60°N, where incidents of these HABs have emerged and expanded in recent decades. Widespread trends were less evident across the North Pacific, although regions were identified across the Salish Sea and along the Alaskan coastline where blooms have recently emerged, and there have been significant increases in the potential growth rates and duration of these HAB events. We conclude that increasing ocean temperature is an important factor facilitating the intensification of these, and likely other, HABs and thus contributes to an expanding human health threat.

Ocean warming since 1982 has expanded the niche of toxic algal blooms in the North Atlantic and North Pacific oceans

PubMed Central

Gobler, Christopher J.; Doherty, Owen M.; Hattenrath-Lehmann, Theresa K.; Griffith, Andrew W.; Kang, Yoonja; Litaker, R. Wayne

2017-01-01

Global ocean temperatures are rising, yet the impacts of such changes on harmful algal blooms (HABs) are not fully understood. Here we used high-resolution sea-surface temperature records (1982 to 2016) and temperature-dependent growth rates of two algae that produce potent biotoxins, Alexandrium fundyense and Dinophysis acuminata, to evaluate recent changes in these HABs. For both species, potential mean annual growth rates and duration of bloom seasons significantly increased within many coastal Atlantic regions between 40°N and 60°N, where incidents of these HABs have emerged and expanded in recent decades. Widespread trends were less evident across the North Pacific, although regions were identified across the Salish Sea and along the Alaskan coastline where blooms have recently emerged, and there have been significant increases in the potential growth rates and duration of these HAB events. We conclude that increasing ocean temperature is an important factor facilitating the intensification of these, and likely other, HABs and thus contributes to an expanding human health threat. PMID:28439007

40 CFR 86.004-28 - Compliance with emission standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... factor may not be appropriate in cases where testing variability is significantly greater than engine-to-engine variability. Multiplicative deterioration factors must be specified to one more significant figure... regenerations are increasing exhaust gas temperature to remove sulfur from an adsorber or increasing exhaust gas...

Evapotranspiration trends over the eastern United States during the 20th century

USGS Publications Warehouse

Kramer, Ryan J.; Bounoua, Lahouari; Zhang, Ping; Wolfe, Robert E.; Huntington, Thomas G.; Imhoff, Marc L.; Thome, Kurtis; Noyce, Genevieve L.

2015-01-01

Most models evaluated by the Intergovernmental Panel for Climate change estimate projected increases in temperature and precipitation with rising atmospheric CO2 levels. Researchers have suggested that increases in CO2 and associated increases in temperature and precipitation may stimulate vegetation growth and increase evapotranspiration (ET), which acts as a cooling mechanism, and on a global scale, may slow the climate-warming trend. This hypothesis has been modeled under increased CO2 conditions with models of different vegetation-climate dynamics. The significance of this vegetation negative feedback, however, has varied between models. Here we conduct a century-scale observational analysis of the Eastern US water balance to determine historical evapotranspiration trends and whether vegetation greening has affected these trends. We show that precipitation has increased significantly over the twentieth century while runoff has not. We also show that ET has increased and vegetation growth is partially responsible.

Color of hot soup modulates postprandial satiety, thermal sensation, and body temperature in young women.

PubMed

Suzuki, Maki; Kimura, Rie; Kido, Yasue; Inoue, Tomoko; Moritani, Toshio; Nagai, Narumi

2017-07-01

The color of food is known to modulate not only consumers' motivation to eat, but also thermal perception. Here we investigated whether the colors of hot soup can influence thermal sensations and body temperature, in addition to the food acceptability and appetite. Twelve young female participants consumed commercial white potage soup, modified to yellow or blue by adding food dyes, at 9 a.m. on 3 separated days. During the test, visual impression (willingness to eat, palatability, comfort, warmth, and anxiety) and thermal sensations were self-reported using visual analog scales. Core (intra-aural) and peripheral (toe) temperatures were continuously recorded 10 min before and 60 min after ingestion. Blue soup significantly decreased willingness to eat, palatability, comfort, and warmth ratings, and significantly increased anxiety feelings compared to the white and yellow soups. After ingestion, the blue soup showed significantly smaller satiety ratings and the tendency of lower thermal sensation scores of the whole body compared to the white and yellow soups. Moreover, a significantly greater increase in toe temperature was found with the yellow soup than the white or blue soup. In conclusion, this study provides new evidence that the colors of hot food may modulate postprandial satiety, thermal sensations and peripheral temperature. Such effects of color may be useful for dietary strategies for individuals who need to control their appetite. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Trends in extreme daily temperatures and humidex index in the United Arab Emirates over 1948-2014.

NASA Astrophysics Data System (ADS)

Yang, H. W.; Ouarda, T.

2015-12-01

This study deals with the analysis of the characteristics of extreme temperature events in the Middle East, using NCEP reanalysis gridded data, for the summer (May-October) and winter (November-April) seasons. Trends in the occurrences of three types of heat spells during 1948-2014 are studied by both Linear Regression (LR) and Mann-Kendall (MK) test. Changes in the diurnal temperature range (DTR) are also investigated. To better understand the effects of heat spells on public health, the Humidex, a combination index of ambient temperature and relative humidity, is also used. Using percentile threshold, temperature (Humidex) Type-A and Type-B heat spells are defined respectively by daily maximum and minimum temperature (Humidex). Type-C heat spells are defined as the joint occurrence of Type-A and Type-B heat spells at the same time. In the Middle East, it is found that no coherent trend in temperature Type-A heat spells is observed. However, the occurrences of temperature Type-B and C heat spells have consistently increased since 1948. For Humidex heat spells, coherently increased activities of all three types of heat spells are observed in the area. During the summer, the magnitude of the positive trends in Humidex heat spells are generally stronger than temperature heat spells. More than half of the locations in the area show significantly negative DTR trends in the summer, but the trends vary according to the region in the winter. Annual mean temperature has increased an average by 0.5°C, but it is mainly associated with the daily minimum temperature which has warmed up by 0.84°C.Daily maximum temperature showed no significant trends. The warming is hence stronger in minimum temperatures than in maximum temperatures resulting in a decrease in DTR by 0.16 °C per decade. This study indicates hence that the UAE has not become hotter, but it has become less cold during 1948 to 2014.

Ecophysiological responses of juvenile seabass (Dicentrarchus labrax) exposed to increased temperature and dietary methylmercury.

PubMed

Maulvault, Ana Luísa; Barbosa, Vera; Alves, Ricardo; Custódio, Ana; Anacleto, Patrícia; Repolho, Tiago; Pousão Ferreira, Pedro; Rosa, Rui; Marques, António; Diniz, Mário

2017-05-15

The ecotoxicological effects of methylmercury (MeHg) exposure have been intensively described in literature. Yet, it is still unclear how marine biota will respond to the presence of MeHg under climate change, namely ocean warming. The present study aimed to investigate, for the first time, fish condition [Fulton's K index (K), hepatosomatic index (HIS) and brain-to-body mass ratio (BB-ratio)] and several stress-related responses in an ecologically and commercially important fish species (Dicentrachus labrax) exposed for 28days to dietary MeHg (8.0mg kg-1 dw) and temperature increase (+4°C). Results showed significant impairments on fish condition, i.e. up to 34% decrease on K, >100% increase on HIS and 44% decrease on BB-ratio, compared to control conditions. Significant changes on tissue biochemical responses were observed in fish exposed to both stressors, acting alone or combined, evidencing the relevance of assessing possible interactions between different environmental stressors in ecotoxicological studies. For instance, muscle showed to be the least affected tissue, only revealing significant alterations in GST activity of MeHg-enriched fish. On the other hand, liver exhibited a significant induction of GST (>100%) and CAT (up to 74%) in MeHg-enriched fish, regardless of temperature exposure, as well as decreased SOD activity (19%) and increased HSP70/HSC70 content (87%) in fish exposed to warming alone. Brain showed to be affected by temperature (69% of GST inhibition and >100% of increased CAT activity), MeHg (>100% of increased CAT activity, 47% of SOD inhibition and 55% of AChE inhibition), as well as by the combination of both (GST, SOD and AChE inhibition, 17%, 48% and 53%, respectively). Hence, our data provides evidences that the toxicological aspects of MeHg ca be potentiated by warmer temperatures, thus, evidencing the need for further research combining contaminants exposure and climate change effects, to better forecast ecological impacts in the ocean of tomorrow. Copyright © 2017 Elsevier B.V. All rights reserved.

Resilience to temperature and pH changes in a future climate change scenario in six strains of the polar diatom Fragilariopsis cylindrus

NASA Astrophysics Data System (ADS)

Pančić, M.; Hansen, P. J.; Tammilehto, A.; Lundholm, N.

2015-07-01

The effects of ocean acidification and increased temperature on physiology of six strains of the polar diatom Fragilariopsis cylindrus from Greenland were investigated. Experiments were performed under manipulated pH levels (8.0, 7.7, 7.4, and 7.1) and different temperatures (1, 5, and 8 °C) to simulate changes from present to plausible future levels. Each of the 12 scenarios was run for 7 days, and a significant interaction between temperature and pH on growth was detected. By combining increased temperature and acidification, the two factors counterbalanced each other, and therefore no effect on the growth rates was found. However, the growth rates increased with elevated temperatures by ~ 20-50 % depending on the strain. In addition, a general negative effect of increasing acidification on growth was observed. At pH 7.7 and 7.4, the growth response varied considerably among strains. However, a more uniform response was detected at pH 7.1 with most of the strains exhibiting reduced growth rates by 20-37 % compared to pH 8.0. It should be emphasized that a significant interaction between temperature and pH was found, meaning that the combination of the two parameters affected growth differently than when considering one at a time. Based on these results, we anticipate that the polar diatom F. cylindrus will be unaffected by changes in temperature and pH within the range expected by the end of the century. In each simulated scenario, the variation in growth rates among the strains was larger than the variation observed due to the whole range of changes in either pH or temperature. Climate change may therefore not affect the species as such, but may lead to changes in the population structure of the species, with the strains exhibiting high phenotypic plasticity, in terms of temperature and pH tolerance towards future conditions, dominating the population.

Resilience to temperature and pH changes in a future climate change scenario in six strains of the polar diatom Fragilariopsis cylindrus

NASA Astrophysics Data System (ADS)

Pančić, M.; Hansen, P. J.; Tammilehto, A.; Lundholm, N.

2015-03-01

The effects of ocean acidification and increased temperature on physiology of six strains of the polar diatom Fragilariopsis cylindrus from Greenland were investigated. Experiments were performed under manipulated pH levels (8.0, 7.7, 7.4, and 7.1) and different temperatures (1, 5 and 8 °C) to simulate changes from present to plausible future levels. Each of the 12 scenarios was run for 7 days, and a significant interaction between temperature and pH on growth was detected. By combining increased temperature and acidification, the two factors counterbalanced each other, and therefore no effect on the growth rates was found. However, the growth rates increased with elevated temperatures by ∼20-50% depending on the strain. In addition, a general negative effect of increasing acidification on growth was observed. At pH 7.7 and 7.4, the growth response varied considerably among strains. However, a more uniform response was detected at pH 7.1 with most of the strains exhibiting reduced growth rates by 20-37% compared to pH 8.0. It should be emphasized that a significant interaction between temperature and pH was found, meaning that the combination of the two parameters affected growth differently than when considering one at a time. Based on these results, we anticipate that the polar diatom F. cylindrus will be unaffected by changes in temperature and pH within the range expected by the end of the century. In each simulated scenario, the variation in growth rates among the strains was larger than the variation observed due to the whole range of changes in either pH or temperature. Climate change may therefore not affect the species as such, but may lead to changes in the population structure of the species, with the strains exhibiting high phenotypic plasticity, in terms of temperature and pH tolerance towards future conditions, dominating the population.

Ambient temperature and added heat wave effects on hospitalizations in California from 1999 to 2009.

PubMed

Sherbakov, Toki; Malig, Brian; Guirguis, Kristen; Gershunov, Alexander; Basu, Rupa

2018-01-01

Investigators have examined how heat waves or incremental changes in temperature affect health outcomes, but few have examined both simultaneously. We utilized distributed lag nonlinear models (DLNM) to explore temperature associations and evaluate possible added heat wave effects on hospitalizations in 16 climate zones throughout California from May through October 1999-2009. We define heat waves as a period when daily mean temperatures were above the zone- and month-specific 95th percentile for at least two consecutive days. DLNMs were used to estimate climate zone-specific non-linear temperature and heat wave effects, which were then combined using random effects meta-analysis to produce an overall estimate for each. With higher temperatures, admissions for acute renal failure, appendicitis, dehydration, ischemic stroke, mental health, non-infectious enteritis, and primary diabetes were significantly increased, with added effects from heat waves observed for acute renal failure and dehydration. Higher temperatures also predicted statistically significant decreases in hypertension admissions, respiratory admissions, and respiratory diseases with secondary diagnoses of diabetes, though heat waves independently predicted an added increase in risk for both respiratory types. Our findings provide evidence that both heat wave and temperature exposures can exert effects independently. Copyright © 2017 Elsevier Inc. All rights reserved.

How pH, Temperature, and Time of Incubation Affect False-Positive Responses and Uncertainty of the LAL Gel-Clot Test.

PubMed

Lourenço, Felipe Rebello; Botelho, Túlia De Souza; Pinto, Terezinha De Jesus Andreoli

2012-01-01

The limulus amebocyte lysate (LAL) test is the simplest and most widely used procedure for detection of endotoxin in parenteral drugs. The LAL test demands optimal pH, ionic strength, temperature, and time of incubation. Slight changes in these parameters may increase the frequency of false-positive responses and the estimated uncertainty of the LAL test. The aim of this paper is to evaluate how changes in the pH, temperature, and time of incubation affect the occurrence of false-positive responses in the LAL test. LAL tests were performed in nominal conditions (37 °C, 60 min, and pH 7) and in different conditions of temperature (36 °C and 38 °C), time of incubation (58 and 62 min), and pH (6 and 8). Slight differences in pH increase the frequency of false-positive responses 5-fold (relative risk 5.0), resulting in an estimated of uncertainty 7.6%. Temperature and time of incubation affect the LAL test less, showing relative risks of 1.5 and 1.0, respectively. Estimated uncertainties in 36 °C or 38 °C temperatures and 58 or 62 min of incubation were found to be 2.0% and 1.0%, respectively. Simultaneous differences in these parameters significantly increase the frequency of false-positive responses. The limulus amebocyte lysate (LAL) gel-clot test is a simple test for detection of endotoxin from Gram-negative bacteria. The test is based on a gel formation when a certain amount of endotoxin is present; it is a pass/fail test. The LAL test requires optimal pH, ionic strength, temperature, and time of incubation. Slight difference in these parameters may increase the frequency of false-positive responses. The aim of this paper is to evaluate how changes in the pH, temperature, and time of incubation affect the occurrence of false-positive responses in the LAL test. We find that slight differences in pH increase the frequency of false-positive responses 5-fold. Temperature and time of incubation affect the LAL test less. Simultaneous differences in these parameters significantly increase the frequency of false-positive responses.

Numerical analysis of temperature field improvement with nanoparticles designed to achieve critical power dissipation in magnetic hyperthermia

NASA Astrophysics Data System (ADS)

Tang, Yundong; Flesch, Rodolfo C. C.; Jin, Tao

2017-07-01

Magnetic nanoparticle (MNP) hyperthermia is a promising emerging therapy for cancer treatment that is minimally invasive and has been successfully used to treat different types of tumors. The power dissipation of MNPs, which is one of the most important factors during a hyperthermia treatment, is determined by the properties of MNPs and characteristics of the magnetic field. This paper proposes a method based on the finite element analysis for determining the value of the power dissipation of particles (PDP) that can maximize the average temperature of the tumor during treatment and at the same time guarantee that the maximum temperature is within the therapeutic range. The application of the critical PDP value can improve the effectiveness of the treatment since it increases the average temperature in the tumor region while limiting the damage to the healthy tissue that surrounds it. After the critical PDP is determined for a specific model, it is shown how the properties of the MNPs can be chosen to achieve the desired PDP value. The transient behavior of the temperature distribution for two different models considering blood vessels is analyzed as a case study, showing that the presence of a blood vessel inside the tumor region can significantly decrease the uniformity of the temperature field and also increase the treatment duration given its cooling effects. To present a solution that does not depend upon a good model of the tumor region, an alternative method that uses MNPs with low Curie temperature is proposed, given the temperature self-regulating properties of such MNPs. The results demonstrate that the uniformity of the temperature field can be significantly increased by combining the optimization procedure proposed in this paper with the use of low-Curie-temperature MNPs.

The Effect of Temperature on Moisture Transport in Concrete.

PubMed

Wang, Yao; Xi, Yunping

2017-08-09

Most concrete structures and buildings are under temperature and moisture variations simultaneously. Thus, the moisture transport in concrete is driven by the moisture gradient as well as the temperature gradient. This paper presents an experimental approach for determining the effect of different temperature gradients on moisture distribution profiles in concrete. The effect of elevated temperatures under isothermal conditions on the moisture transport was also evaluated, and found not to be significant. The non-isothermal tests show that the temperature gradient accelerates the moisture transport in concrete. The part of increased moisture transfer due to the temperature gradient can be quantified by a coupling parameter D HT , which can be determined by the present test data. The test results indicated that D HT is not a constant but increases linearly with the temperature variation. A material model was developed for D HT based on the experimental results obtained in this study.

Hydraulic fracturing and permeability enhancement in granite from subcritical/brittle to supercritical/ductile conditions

NASA Astrophysics Data System (ADS)

Watanabe, Noriaki; Egawa, Motoki; Sakaguchi, Kiyotoshi; Ishibashi, Takuya; Tsuchiya, Noriyoshi

2017-06-01

Hydraulic fracturing experiments were conducted at 200-450°C by injecting water into cylindrical granite samples containing a borehole at an initial effective confining pressure of 40 MPa. Intensive fracturing was observed at all temperatures, but the fracturing characteristics varied with temperature, perhaps due to differences in the water viscosity. At the lowest considered temperature (200°C), fewer fractures propagated linearly from the borehole, and the breakdown pressure was twice the confining pressure. However, these characteristics disappeared with increasing temperature; the fracture pattern shifted toward the formation of a greater number of shorter fractures over the entire body of the sample, and the breakdown pressure decreased greatly. Hydraulic fracturing significantly increased the permeability at all temperatures, and this permeability enhancement was likely to form a productive geothermal reservoir even at the highest considered temperature, which exceeded both the brittle-ductile transition temperature of granite and the critical temperature of water.

The Effect of Temperature on Moisture Transport in Concrete

PubMed Central

Wang, Yao; Xi, Yunping

2017-01-01

Most concrete structures and buildings are under temperature and moisture variations simultaneously. Thus, the moisture transport in concrete is driven by the moisture gradient as well as the temperature gradient. This paper presents an experimental approach for determining the effect of different temperature gradients on moisture distribution profiles in concrete. The effect of elevated temperatures under isothermal conditions on the moisture transport was also evaluated, and found not to be significant. The non-isothermal tests show that the temperature gradient accelerates the moisture transport in concrete. The part of increased moisture transfer due to the temperature gradient can be quantified by a coupling parameter DHT, which can be determined by the present test data. The test results indicated that DHT is not a constant but increases linearly with the temperature variation. A material model was developed for DHT based on the experimental results obtained in this study. PMID:28792460

Waterfowl Conservation in the US Prairie Pothole Region: Confronting the Complexities of Climate Change

PubMed Central

Niemuth, Neal D.; Fleming, Kathleen K.; Reynolds, Ronald E.

2014-01-01

The Prairie Pothole Region (PPR) is the most important waterfowl production area in North America. However, waterfowl populations there are predicted to decline because of climate-related drying of wetlands. Consequently, changes in the geographic focus of PPR waterfowl conservation have been recommended, which could have long-lasting and costly impacts. We used a 40-year dataset of pond counts collected in the PPR to test hypotheses about climate-related drying. We assessed May (1974–2013) and July (1974–2003) pond numbers in 20 waterfowl survey strata to determine if trends in pond numbers were consistent with predictions of drying. We also assessed trends in precipitation and temperature for the 20 strata and developed models describing May pond numbers from 1974 through 2010 as a function of precipitation, temperature, the previous year’s pond numbers, and location. None of the 20 strata showed significant declines in May pond numbers, although seven strata showed increases over time. July pond numbers declined significantly in one stratum, and increased in seven strata. An index to hydroperiod showed significant increasing trends in three strata, and no strata had decreasing trends. Precipitation increased significantly in two strata and decreased in two from 1974 to 2010; no strata showed significant changes in temperature. The best linear model described pond numbers within all strata as a function of precipitation, temperature, the previous year’s pond numbers, and the latitude and longitude of the stratum, and explained 62% of annual variation in pond numbers. We hypothesize that direct effects of climate change on prairie pothole wetlands and waterfowl may be overshadowed by indirect effects such as intensified land use and increased pressure to drain wetlands. We recommend that an adaptive, data-driven approach be used to resolve uncertainties regarding direct and indirect effects of climate change on prairie wetlands and waterfowl, and guide future conservation efforts. PMID:24937641

Waterfowl conservation in the US Prairie Pothole Region: confronting the complexities of climate change.

PubMed

Niemuth, Neal D; Fleming, Kathleen K; Reynolds, Ronald E

2014-01-01

The Prairie Pothole Region (PPR) is the most important waterfowl production area in North America. However, waterfowl populations there are predicted to decline because of climate-related drying of wetlands. Consequently, changes in the geographic focus of PPR waterfowl conservation have been recommended, which could have long-lasting and costly impacts. We used a 40-year dataset of pond counts collected in the PPR to test hypotheses about climate-related drying. We assessed May (1974-2013) and July (1974-2003) pond numbers in 20 waterfowl survey strata to determine if trends in pond numbers were consistent with predictions of drying. We also assessed trends in precipitation and temperature for the 20 strata and developed models describing May pond numbers from 1974 through 2010 as a function of precipitation, temperature, the previous year's pond numbers, and location. None of the 20 strata showed significant declines in May pond numbers, although seven strata showed increases over time. July pond numbers declined significantly in one stratum, and increased in seven strata. An index to hydroperiod showed significant increasing trends in three strata, and no strata had decreasing trends. Precipitation increased significantly in two strata and decreased in two from 1974 to 2010; no strata showed significant changes in temperature. The best linear model described pond numbers within all strata as a function of precipitation, temperature, the previous year's pond numbers, and the latitude and longitude of the stratum, and explained 62% of annual variation in pond numbers. We hypothesize that direct effects of climate change on prairie pothole wetlands and waterfowl may be overshadowed by indirect effects such as intensified land use and increased pressure to drain wetlands. We recommend that an adaptive, data-driven approach be used to resolve uncertainties regarding direct and indirect effects of climate change on prairie wetlands and waterfowl, and guide future conservation efforts.

Elevating body temperature enhances hematopoiesis and neutrophil recovery after total body irradiation in an IL-1-, IL-17-, and G-CSF-dependent manner.

PubMed

Capitano, Maegan L; Nemeth, Michael J; Mace, Thomas A; Salisbury-Ruf, Christi; Segal, Brahm H; McCarthy, Philip L; Repasky, Elizabeth A

2012-09-27

Neutropenia is a common side effect of cytotoxic chemotherapy and radiation, increasing the risk of infection in these patients. Here we examined the impact of body temperature on neutrophil recovery in the blood and bone marrow after total body irradiation (TBI). Mice were exposed to either 3 or 6 Gy TBI followed by a mild heat treatment that temporarily raised core body temperature to approximately 39.5°C. Neutrophil recovery was then compared with control mice that received either TBI alone heat treatment alone. Mice that received both TBI and heat treatment exhibited a significant increase in the rate of neutrophil recovery in the blood and an increase in the number of marrow hematopoietic stem cells and neutrophil progenitors compared with that seen in mice that received either TBI or heat alone. The combination treatment also increased G-CSF concentrations in the serum, bone marrow, and intestinal tissue and IL-17, IL-1β, and IL-1α concentrations in the intestinal tissue after TBI. Neutralizing G-CSF or inhibiting IL-17 or IL-1 signaling significantly blocked the thermally mediated increase in neutrophil numbers. These findings suggest that a physiologically relevant increase in body temperature can accelerate recovery from neutropenia after TBI through a G-CSF-, IL-17-, and IL-1-dependent mechanism.

Elevating body temperature enhances hematopoiesis and neutrophil recovery after total body irradiation in an IL-1–, IL-17–, and G-CSF–dependent manner

PubMed Central

Capitano, Maegan L.; Nemeth, Michael J.; Mace, Thomas A.; Salisbury-Ruf, Christi; Segal, Brahm H.; McCarthy, Philip L.

2012-01-01

Neutropenia is a common side effect of cytotoxic chemotherapy and radiation, increasing the risk of infection in these patients. Here we examined the impact of body temperature on neutrophil recovery in the blood and bone marrow after total body irradiation (TBI). Mice were exposed to either 3 or 6 Gy TBI followed by a mild heat treatment that temporarily raised core body temperature to approximately 39.5°C. Neutrophil recovery was then compared with control mice that received either TBI alone heat treatment alone. Mice that received both TBI and heat treatment exhibited a significant increase in the rate of neutrophil recovery in the blood and an increase in the number of marrow hematopoietic stem cells and neutrophil progenitors compared with that seen in mice that received either TBI or heat alone. The combination treatment also increased G-CSF concentrations in the serum, bone marrow, and intestinal tissue and IL-17, IL-1β, and IL-1α concentrations in the intestinal tissue after TBI. Neutralizing G-CSF or inhibiting IL-17 or IL-1 signaling significantly blocked the thermally mediated increase in neutrophil numbers. These findings suggest that a physiologically relevant increase in body temperature can accelerate recovery from neutropenia after TBI through a G-CSF–, IL-17–, and IL-1–dependent mechanism. PMID:22806894

Physiological responses to the menstrual cycle: implications for the development of heat illness in female athletes.

PubMed

Marsh, Susan A; Jenkins, David G

2002-01-01

Fluctuations in estrogen and progesterone during the menstrual cycle can cause changes in body systems other than the reproductive system. For example, progesterone is involved in the regulation of fluid balance in the renal tubules and innervation of the diaphragm via the phrenic nerve. However, few significant changes in the responses of the cardiovascular and respiratory systems, blood lactate, bodyweight, performance and ratings of perceived exertion are evident across the cycle. Nevertheless, substantial evidence exists to suggest that increased progesterone levels during the luteal phase cause increases in both core and skin temperatures and alter the temperature at which sweating begins during exposure to both ambient and hot environments. As heat illness is characterised by a significant increase in body temperature, it is feasible that an additional increase in core temperature during the luteal phase could place females at an increased risk of developing heat illness during this time. In addition, it is often argued that physiological gender differences such as oxygen consumption, percentage body fat and surface area-to-mass ratio place females at a higher risk of heat illness than males. This review examines various physiological responses to heat exposure during the menstrual cycle at rest and during exercise, and considers whether such changes increase the risk of heat illness in female athletes during a particular phase of the menstrual cycle.

Biofeedback-assisted relaxation training to decrease test anxiety in nursing students.

PubMed

Prato, Catherine A; Yucha, Carolyn B

2013-01-01

Nursing students experiencing debilitating test anxiety may be unable to demonstrate their knowledge and have potential for poor academic performance. A biofeedback-assisted relaxation training program was created to reduce test anxiety. Anxiety was measured using Spielberger's Test Anxiety Inventory and monitoring peripheral skin temperature, pulse, and respiration rates during the training. Participants were introduced to diaphragmatic breathing, progressive muscle relaxation, and autogenic training. Statistically significant changes occurred in respiratory rates and skin temperatures during the diaphragmatic breathing session; respiratory rates and peripheral skin temperatures during progressive muscle relaxation session; respiratory and pulse rates, and peripheral skin temperatures during the autogenic sessions. No statistically significant difference was noted between the first and second TAI. Subjective test anxiety scores of the students did not decrease by the end of training. Autogenic training session was most effective in showing a statistically significant change in decreased respiratory and pulse rates and increased peripheral skin temperature.

Study on the Effect of Thermal and Magnetic Stimulation by Measuring of the Peripheral Blood Flow and Skin Temperature

NASA Astrophysics Data System (ADS)

Kubota, Kouhei; Nuruki, Atsuo; Tamari, Youzou; Yunokuchi, Kazutomo

Recently, the stiff shoulder accompanying the muscle fatigue becomes an issue of public concern. Therefore, we paid attention to the effect of the thermal and magnetic stimulation for the muscle fatigue. The maximum voluntary contraction has recovered significantly, and also peripheral blood flow has increased by stimulation. In order to evaluate if the thermal and magnetic stimulation has any effects, three parameters was measured, which are the maximum voluntary contraction, peripheral blood flow and skin temperature. The skin temperature, however, did not changed significantly.

Modern high powered led curing lights and their effect on pulp chamber temperature of bulk and incrementally cured composite resin.

PubMed

Oberholzer, T G; Makofane, M E; du Preez, I C; George, R

2012-06-01

Pulpal temperature changes induced by modern high powered light emitting diodes (LEDs) are of concern when used to cure composite resins. This study showed an increase in pulp chamber temperature with an increase in power density for all light cure units (LCU) when used to bulk cure composite resin. Amongst the three LEDs tested, the Elipar Freelight-2 recorded the highest temperature changes. Bulk curing recorded a significantly larger rise in pulp chamber temperature change than incrementally cured resin for all light types except for the Smartligh PS. Both the high powered LED and the conventional curing units can generate heat. Though this temperature rise may not be sufficient to cause irreversible pulpal damage, it would be safer to incrementally cure resins.

A component analysis of biofeedback induced self-control of peripheral (finger) temperature.

PubMed

King, N J; Montgomery, R B

1980-03-01

Most of the research on biofeedback induced peripheral temperature control is open to serious methodological and theoretical criticisms. In the present research investigation, increase in peripheral (finger) temperature was targeted because of the possible therapeutic implications for the treatment of migraine and Raynaud's disease. Two experiments are reported in which the pretest-posttest control group design was employed to test the power of the variables in biofeedback induced self-control of finger temperature, and the necessity for subjects to engage in somatic manoeuvres. Significant increases in within-session and absolute finger temperature occurred in a test for self-control only for those subjects who had undergoing contingent feedback-somatic activity training conditions. It is suggested that future research should examine the role of mediational strategies in biofeedback-temperature training.

Secondary pool boiling effects

NASA Astrophysics Data System (ADS)

Kruse, C.; Tsubaki, A.; Zuhlke, C.; Anderson, T.; Alexander, D.; Gogos, G.; Ndao, S.

2016-02-01

A pool boiling phenomenon referred to as secondary boiling effects is discussed. Based on the experimental trends, a mechanism is proposed that identifies the parameters that lead to this phenomenon. Secondary boiling effects refer to a distinct decrease in the wall superheat temperature near the critical heat flux due to a significant increase in the heat transfer coefficient. Recent pool boiling heat transfer experiments using femtosecond laser processed Inconel, stainless steel, and copper multiscale surfaces consistently displayed secondary boiling effects, which were found to be a result of both temperature drop along the microstructures and nucleation characteristic length scales. The temperature drop is a function of microstructure height and thermal conductivity. An increased microstructure height and a decreased thermal conductivity result in a significant temperature drop along the microstructures. This temperature drop becomes more pronounced at higher heat fluxes and along with the right nucleation characteristic length scales results in a change of the boiling dynamics. Nucleation spreads from the bottom of the microstructure valleys to the top of the microstructures, resulting in a decreased surface superheat with an increasing heat flux. This decrease in the wall superheat at higher heat fluxes is reflected by a "hook back" of the traditional boiling curve and is thus referred to as secondary boiling effects. In addition, a boiling hysteresis during increasing and decreasing heat flux develops due to the secondary boiling effects. This hysteresis further validates the existence of secondary boiling effects.

Intrapulpal Thermal Changes during Setting Reaction of Glass Carbomer® Using Thermocure Lamp.

PubMed

Kahvecioglu, Firdevs; Tosun, Gül; Ülker, Hayriye Esra

2016-01-01

Objectives . To measure the temperature increase induced during thermocure lamp setting reaction of glass carbomer and to compare it with those induced by visible light curing of a resin-modified glass ionomer and a polyacid-modified composite resin in primary and permanent teeth. Materials and Methods . Nonretentive class I cavities were prepared in extracted primary and permanent molars. Glass carbomer (GC) was placed in the cavity and set at 60°C for 60 sn using a special thermocure lamp. Resin-modified glass ionomer (RMGIC) and polyacid-modified composite resin (PMCR) were placed in the cavities and polymerized with an LED curing unit. Temperature increases during setting reactions were measured with a J-type thermocouple wire connected to a data logger. Data were examined using two-way analysis of variance and Tukey's honestly significant difference tests. Results . The use of GC resulted in temperature changes of 5.17 ± 0.92°C and 5.32 ± 0.90°C in primary and permanent teeth, respectively ( p > 0.05). Temperature increases were greatest in the GC group, differing significantly from those in the PMCR group ( p < 0.05). Conclusion . Temperature increases during polymerization and setting reactions of the materials were below the critical value in all groups. No difference was observed between primary and permanent teeth, regardless of the material used.

Structure of Laminar Permanently Blue, Opposed-Jet Ethylene-Fueled Diffusion Flames

NASA Technical Reports Server (NTRS)

Lin, K.-C.; Faeth, G. M.; Urban, D. L. (Technical Monitor)

2000-01-01

The structure and state relationships of laminar soot-free (permanently blue) ethylene-fueled diffusion flames at various strain rates were studied both experimentally and computationally using an opposed-jet configuration. Measurements of gas velocities, temperatures, and compositions were carried out along the stagnation stream line. Corresponding predictions of flame structure were obtained, based on numerical simulations using several contemporary reaction mechanisms for methane oxidation. Flame conditions studied included ethylene-fueled opposed-jet diffusion flames having stoichiometric mixture fractions of 0.7 with measurements involving strain rates of 60-240/s and predictions involving strain rates of 0-1140/s at normal temperature and pressure. It was found that measured major gas species concentrations and temperature distributions were in reasonably good agreement with predictions using mechanisms due to GRI-Mech and Peters and that effects of preferential diffusion significantly influence flame structure even when reactant mass diffusivities are similar. Oxygen leakage to fuel-rich conditions and carbon monoxide leakage to fuel-lean conditions both increased as strain rates increased. Furthermore, increased strain rates caused increased fuel concentrations near the flame sheet, decreased peak gas temperatures, and decreased concentrations of carbon dioxide and water vapor throughout the flames. State relationships for major gas species and gas temperatures were found to exist over a broad range of strain rates, providing potential for significant computational simplifications for modeling purposes in some instances.

Structure of Laminar Permanently Blue, Opposed-Jet Ethylene-Fueled Diffusion Flames. Appendix E

NASA Technical Reports Server (NTRS)

Lin, K.-C.; Faeth, G. M.; Urban, D. L. (Technical Monitor)

2000-01-01

The structure and state relationships of laminar soot-free (permanently blue) ethylene-fueled diffusion flames at various strain rates were studied both experimentally and computationally using an opposed-jet configuration. Measurements of gas velocities, temperatures, and compositions were carried out along the stagnation stream line. Corresponding predictions of flame structure were obtained, based on numerical simulations using several contemporary reaction mechanisms for methane oxidation. Flame conditions studied included ethylene-fueled opposed-jet diffusion flames having stoichiometric mixture fractions of 0.7 with measurements involving strain rates of 60-240/s and predictions involving strain rates of 0-1140/s at normal temperature and pressure. It was found that measured major gas species concentrations and temperature distributions were in reasonably good agreement with predictions using mechanisms due to GRI-Mech and Peters and that effects of preferential diffusion significantly influence flame structure even when reactant mass diffusivities are similar. Oxygen leakage to fuel-rich conditions and carbon monoxide leakage to fuel-lean conditions both increased as strain rates increased. Furthermore, increased strain rates caused increased fuel concentrations near the flame sheet, decreased peak gas temperatures, and decreased concentrations of carbon dioxide and water vapor throughout the flames. State relationships for major gas species and gas temperatures were found to exist over a broad range of strain rates, providing potential for significant computational simplifications for modeling purposes in some instances.

Coldest Temperature Extreme Monotonically Increased and Hottest Extreme Oscillated over Northern Hemisphere Land during Last 114 Years.

PubMed

Zhou, Chunlüe; Wang, Kaicun

2016-05-13

Most studies on global warming rely on global mean surface temperature, whose change is jointly determined by anthropogenic greenhouse gases (GHGs) and natural variability. This introduces a heated debate on whether there is a recent warming hiatus and what caused the hiatus. Here, we presented a novel method and applied it to a 5° × 5° grid of Northern Hemisphere land for the period 1900 to 2013. Our results show that the coldest 5% of minimum temperature anomalies (the coldest deviation) have increased monotonically by 0.22 °C/decade, which reflects well the elevated anthropogenic GHG effect. The warmest 5% of maximum temperature anomalies (the warmest deviation), however, display a significant oscillation following the Atlantic Multidecadal Oscillation (AMO), with a warming rate of 0.07 °C/decade from 1900 to 2013. The warmest (0.34 °C/decade) and coldest deviations (0.25 °C/decade) increased at much higher rates over the most recent decade than last century mean values, indicating the hiatus should not be interpreted as a general slowing of climate change. The significant oscillation of the warmest deviation provides an extension of previous study reporting no pause in the hottest temperature extremes since 1979, and first uncovers its increase from 1900 to 1939 and decrease from 1940 to 1969.

Influence of the Environment on Body Temperature of Racing Greyhounds.

PubMed

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

2016-01-01

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

Influence of the Environment on Body Temperature of Racing Greyhounds

PubMed Central

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

2016-01-01

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

The effect of different temperature profiles upon the length and crystallinity of vertically-aligned multi-walled carbon nanotubes.

PubMed

Yun, Jongju; Lee, Cheesung; Zheng, Qing; Baik, Seunghyun

2012-08-01

We synthesized vertically-aligned multi-walled carbon nanotubes with an inner diameter of 1.6-7.5 nm and stack height of 80-28600 microm by chemical vapor deposition. The effects of synthesis conditions such as substrate position in the tube furnace, maximum temperature, temperature increasing rate and synthesis duration on the structure of nanotubes were investigated. It was found that slightly faster temperature increase rate resulted in significantly longer length, larger diameter and more defects of nanotubes. Structural parameters such as inner, outer diameters, wall thickness and defects were investigated using transmission electron microscopy and Raman spectroscopy.

Effect of operating temperature on styrene mass transfer characteristics in a biotrickling filter.

PubMed

Parnian, Parham; Zamir, Seyed Morteza; Shojaosadati, Seyed Abbas

2017-05-01

To study the effect of operating temperature on styrene mass transfer from gas to liquid phase in biotrickling filters (BTFs), overall mass transfer coefficient (K L a) was calculated through fitting test data to a general mass balance model under abiotic conditions. Styrene was used as the volatile organic compound and the BTF was packed with a mixture of pall rings and pumice. Operating temperature was set at 30°C and 50°C for mesophilic and thermophilic conditions, respectively. K L a values increased from 54 to 70 h -1 at 30°C and from 60 to 90 h -1 at 50°C, respectively, depending on the countercurrent gas to liquid flow ratio that varied in the range of 7.5-32. Evaluation of styrene mass transfer capacity (MTC) showed that liquid-phase mass transfer resistance decreased as the flow ratio increased at constant temperature. MTC also decreased with an increase in operating temperature. Both gas-liquid partition coefficient and K L a increased with increasing temperature; however the effect on gas-liquid partition coefficient was more significant and served to increase mass transfer limitations. Thermophilic biofiltration on the one hand increases mass transfer limitations, but on the other hand may enhance the biodegradation rate in favor of enhancing BTFs' performance.

Effects of high temperature frying of Spinach leaves in sunflower oil on carotenoids, chlorophylls and tocopherol composition

NASA Astrophysics Data System (ADS)

Zeb, Alam; Nisar, Parveen

2017-03-01

Spinach is one of the highly consumed vegetable, with significant nutritional and beneficial properties. This study revealed for the first time, the effects of high temperature frying on the carotenoids, chlorophylls and tocopherol contents of spinach leaves. Spinach leaves were thermally processed in the sunflower oil for 15, 30, 45 and 60 min at 250 °C. HPLC-DAD results revealed a total of eight carotenoids, four chlorophylls and α-tocopherol in the spinach leaves. Lutein, neoxanthin, violaxanthin and β-carotene-5,6-epoxide were the major carotenoids, while chlorophyll a and b' were present in higher amounts. Frying of spinach leaves increased significantly the amount of α-tocopherol, β-carotene-5,6-epoxide, luteoxanthin, lutein and its Z-isomers and chlorophyll b' isomer. There was a dose dependent decrease in the amounts of neoxanthin, violaxanthin, chlorophyll b, b' and chlorophyll a with increase of frying time. The increase of frying time increased the total phenolic contents in spinach leaves and fried sunflower oil samples. Chemical characteristics such as peroxide values, free fatty acids, conjugated dienes, conjugated trienes and radical scavenging activity were significantly affected by frying, while spinach leaves increased the stability of the frying oil. This study can be used to improve the quality of fried vegetable leaves or their products at high temperature frying in food industries for increasing consumer acceptability.

The effect of substrate temperature on the microstructural, electrical and optical properties of Sn-doped indium oxide thin films

NASA Astrophysics Data System (ADS)

Raoufi, Davood; Taherniya, Atefeh

2015-06-01

In this work, Sn doping In2O3 (ITO) thin films with a thickness of 200 nm were deposited on glass substrates by electron beam evaporation (EBE) method at different substrate temperatures. The crystal structure of these films was studied by X-ray diffraction technique. The sheet resistance was measured by a four-point probe. Van der Pauw method was used to measure carrier density and mobility of ITO films. The optical transmittance spectra were recorded in the wavelength region of 300-800 nm. Scanning electron microscope (SEM) has been used for the surface morphology analysis. The prepared ITO films exhibited body-centered cubic (BCC) structure with preferred orientation of growth along the (2 2 2) crystalline plane. The grain size of the films increases by rising the substrate temperature. Transparency of the films, over the visible light region, is increased with increasing the substrate temperature. It is found that the electrical properties of ITO films are significantly affected by substrate temperature. The electrical resistivity decreases with increasing substrate temperature, whereas the carrier density and mobility are enhanced with an increase in substrate temperature. The evaluated values of energy band gap Eg for ITO films were increase from 3.84 eV to 3.91 eV with increasing the substrate temperatures from 200 °C to 500 °C. The SEM micrographs of the films revealed a homogeneous growth without perceptible cracks with particles which are well covered on the substrate.

Facing warm temperatures during migration: cardiac mRNA responses of two adult Oncorhynchus nerka populations to warming and swimming challenges.

PubMed

Anttila, K; Eliason, E J; Kaukinen, K H; Miller, K M; Farrell, A P

2014-05-01

The main findings of the current study were that exposing adult sockeye salmon Onchorhynchus nerka to a warm temperature that they regularly encounter during their river migration induced a heat shock response at an mRNA level, and this response was exacerbated with forced swimming. Similar to the heat shock response, increased immune defence-related responses were also observed after warm temperature treatment and with a swimming challenge in two different populations (Chilko and Nechako), but with some important differences. Microarray analyses revealed that 347 genes were differentially expressed between the cold (12-13° C) and warm (18-19° C) treated fish, with stress response (GO:0006950) and response to fungus (GO:0009620) elevated with warm treatment, while expression for genes involved in oxidative phosphorylation (GO:0006119) and electron transport chain (GO:0022900) elevated for cold-treated fish. Analysis of single genes with real-time quantitative PCR revealed that temperature had the most significant effect on mRNA expression levels, with swimming and population having secondary influences. Warm temperature treatment for the Chilko population induced expression of heat shock protein (hsp) 90α, hsp90β and hsp30 as well as interferon-inducible protein. The Nechako population, which is known to have a narrower thermal tolerance window than the Chilko population, showed even more pronounced stress responses to the warm treatment and there was significant interaction between population and temperature treatment for hsp90β expression. Moreover, significant interactions were noted between temperature treatment and swimming challenge for hsp90α and hsp30, and while swimming challenge alone increased expression of these hsps, the expression levels were significantly elevated in warm-treated fish swum to exhaustion. In conclusion, it seems that adult O. nerka currently encounter conditions that induce several cellular defence mechanisms during their once-in-the-lifetime migration. As river temperatures continue to increase, it remains to be seen whether or not these cellular defences provide sufficient protection for all O. nerka populations. © 2014 The Fisheries Society of the British Isles.

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.

Quality evaluation of onion bulbs during low temperature drying

NASA Astrophysics Data System (ADS)

Djaeni, M.; Asiah, N.; Wibowo, Y. P.; Yusron, D. A. A.

2016-06-01

A drying technology must be designed carefully by evaluating the foods' final quality properties as a dried material. Thermal processing should be operated with the minimum chance of substantial flavour, taste, color and nutrient loss. The main objective of this research was to evaluate the quality parameters of quercetin content, color, non-enzymatic browning and antioxidant activity. The experiments showed that heating at different temperatures for several drying times resulted in a percentage of quercetin being generally constant. The quercetin content maintained at the value of ±1.2 % (dry basis). The color of onion bulbs was measured by CIE standard illuminant C. The red color (a*) of the outer layer of onion bulbs changed significantly when the drying temperature was increased. However the value of L* and b* changed in a fluctuating way based on the temperature. The change of onion colors was influenced by temperature and moisture content during the drying process. The higher the temperature, the higher it affects the rate of non-enzymatic browning reaction. The correlation between temperature and reaction rate constant was described as Arrhenius equation. The rate of non-enzymatic browning increases along with the increase of drying temperature. The results showed that higher drying temperatures were followed by a lower IC10. This condition indicated the increase of antioxidant activity after the drying process.

Assessing vegetation response to climatic variations and human activities: spatiotemporal NDVI variations in the Hexi Corridor and surrounding areas from 2000 to 2010

NASA Astrophysics Data System (ADS)

Guan, Qingyu; Yang, Liqin; Guan, Wenqian; Wang, Feifei; Liu, Zeyu; Xu, Chuanqi

2018-03-01

Vegetation cover is a commonly used indicator for evaluating terrestrial environmental conditions, and for revealing environmental evolution and transitions. Spatiotemporal variations in the vegetation cover of the Hexi Corridor and surrounding areas from 2000 to 2010 were investigated using MODIS NDVI data, and the causes of vegetation cover changes were analyzed, considering both climatic variability and human activities. The vegetation cover of the study area increased during 2000-2010. The greenness of the vegetation showed a significant increase from the northwest to the southeast, which was similar to the spatial distribution of the annual precipitation. Variations in vegetation have a close relationship with those in precipitation within the Qilian Mountains region, but the NDVI is negatively correlated with precipitation in oasis areas. Increasing temperatures led to drought, inhibiting vegetation growth in summer; however, increasing temperatures may have also advanced and prolonged the growing periods in spring and autumn. The NDVI showed a slight degradation in March and July, primarily in the Qilian Mountains, and especially the Wushao Mountains. In March, due to low temperatures, the metabolism rate of vegetation was too slow to enable strong plant growth in high elevations of the Qilian Mountains. In July, increasing temperatures enhanced the intensity of transpiration and decreasing precipitation reduced the moisture available to plants, producing a slight degradation of vegetation in the Qilian Mountains. In May and August, the NDVI showed a significant improvement, primarily in the artificial oases and the Qilian Mountains. Abundant precipitation provided the necessary water for plant growth, and suitable temperatures increased the efficiency of photosynthesis, resulting in a significant improvement of vegetation in the Qilian Mountains. The improvement of production technologies, especially in irrigation, has been beneficial to the growth of vegetation in oasis areas. The implementation of large-scale vegetation management has led to several beneficial effects in the artificial oases and grasslands of the Qilian Mountains. [Figure not available: see fulltext.

Low Temperature Induced Changes in Citrate Metabolism in Ponkan (Citrus reticulata Blanco cv. Ponkan) Fruit during Maturation

PubMed Central

Lin, Qiong; Qian, Jing; Zhao, Chenning; Wang, Dengliang; Liu, Chunrong; Wang, Zhidong; Sun, Chongde; Chen, Kunsong

2016-01-01

Citrate is the most important organic acid in citrus fruit, and its concentration in fruit cells is regulated mainly by the balance between synthesis and degradation. Ponkan (Citrus reticulate Blanco cv. Ponkan) is one of the major citrus cultivars grew in China, and the fruit are picked before fully mature to avoid bad weather. Greenhouse production is widely used to prolong the maturation period and improve the quality of Ponkan fruit by maintaining adequate temperature and providing protection from adverse weather. In this research, Ponkan fruit cultivated in either a greenhouse or open field were used to investigate differences in the expression of genes related to citrate metabolism during maturation in the two environments. The citrate contents were higher in open field fruit, and were mainly correlated with expressions of CitPEPCs, CitCSs, CitAco3 and CitGAD4, which were significantly increased. In addition, the impacts of low temperature (LT) and water stress (WS) on citrate metabolism in Ponkan were investigated during fruit maturation. The citrate contents in LT fruit were significantly increased, by between 1.4–1.9 fold, compared to the control; it showed no significant difference in fruit with water stress treatment compared to the control fruit. Furthermore, the expressions of CitPEPCs, CitCSs, CitAco3 and CitGAD4 were significantly increased in response to LT treatment, but showed no significant difference in WS compared to the control fruit. Thus, it can be concluded that low temperature may be the main factor influencing citrate metabolism during maturation in Ponkan fruit. PMID:27249065

3D microenvironment as essential element for osteoinduction by biomaterials.

PubMed

Habibovic, Pamela; Yuan, Huipin; van der Valk, Chantal M; Meijer, Gert; van Blitterswijk, Clemens A; de Groot, Klaas

2005-06-01

In order to unravel the mechanism of osteoinduction by biomaterials, in this study we investigated the influence of the specific surface area on osteoinductive properties of two types of calcium phosphate ceramics. Different surface areas of the ceramics were obtained by varying their sintering temperatures. Hydroxyapatite (HA) ceramic was sintered at 1150 and 1250 degrees C. Biphasic calcium phosphate (BCP) ceramic, consisting of HA and beta-tricalcium phosphate (beta-TCP), was sintered at 1100, 1150 and 1200 degrees C. Changes in sintering temperature did not influence the chemistry of the ceramics; HA remained pure after sintering at different temperatures and the weight ratio of HA and beta-TCP in the BCP was independent of the temperature as well. Similarly, macroporosity of the ceramics was unaffected by the changes of the sintering temperature. However, microporosity (pore diameter <10 microm) significantly decreased with increasing sintering temperature. In addition to the decrease of the microporosity, the crystal size increased with increasing sintering temperature. These two effects resulted in a significant decrease of the specific surface area of the ceramics with increasing sintering temperatures. Samples of HA1150, HA1250, BCP1100, BCP1150 and BCP1200 were implanted in the back muscles of Dutch milk goats and harvested at 6 and 12 weeks post implantation. After explantation, histomorphometrical analysis was performed on all implants. All implanted materials except HA1250 induced bone. However, large variations in the amounts of induced bone were observed between different materials and between individual animals. Histomorphometrical results showed that the presence of micropores within macropore walls is necessary to make a material osteoinductive. We postulate that introduction of microporosity within macropores, and consequent increase of the specific surface area, affects the interface dynamics of the ceramic in such a way that relevant cells are triggered to differentiate into the osteogenic lineage.

The effect of ambient temperature on type-2-diabetes: case-crossover analysis of 4+ million GP consultations across England.

PubMed

Hajat, S; Haines, A; Sarran, C; Sharma, A; Bates, C; Fleming, L E

2017-07-12

Given the double jeopardy of global increases in rates of obesity and climate change, it is increasingly important to recognise the dangers posed to diabetic patients during periods of extreme weather. We aimed to characterise the associations between ambient temperature and general medical practitioner consultations made by a cohort of type-2 diabetic patients. Evidence on the effects of temperature variation in the primary care setting is currently limited. Case-crossover analysis of 4,474,943 consultations in England during 2012-2014, linked to localised temperature at place of residence for each patient. Conditional logistic regression was used to assess associations between each temperature-related consultation and control days matched on day-of-week. There was an increased odds of seeking medical consultation associated with high temperatures: Odds ratio (OR) = 1.097 (95% confidence interval = 1.041, 1.156) per 1 °C increase above 22 °C. Odds during low temperatures below 0 °C were also significantly raised: OR = 1.024 (1.019, 1.030). Heat-related consultations were particularly high among diabetics with cardiovascular comorbidities: OR = 1.171 (1.031, 1.331), but there was no heightened risk with renal failure or neuropathy comorbidities. Surprisingly, lower odds of heat-related consultation were associated with the use of diuretics, anticholinergics, antipsychotics or antidepressants compared to non-use, especially among those with cardiovascular comorbidities, although differences were not statistically significant. Type-2 diabetic patients are at increased odds of medical consultation during days of temperature extremes, especially during hot weather. The common assumption that certain medication use heightens the risk of heat illness was not borne-out by our study on diabetics in a primary care setting and such advice may need to be reconsidered in heat protection plans.

Photosynthetic temperature adaptation of Pinus cembra within the timberline ecotone of the Central Austrian Alps

PubMed Central

Wieser, Gerhard; Oberhuber, Walter; Walder, Lisa; Spieler, Daniela; Gruber, Andreas

2011-01-01

Temperature is suggested to determine the upper limit of tree life. Therefore, future climate warming may be of importance for tree distribution within the European Alps, where low temperatures limit carbon metabolism. We focused on the effects of air and soil temperature on net photosynthesis (Pn) of Pinus cembra an evergreen climax species of the timberline ecotone of the Central Austrian Alps. Light response and temperature response curves were estimated along an altitudinal gradient ranging from the forest limit up to the krummholz limit in both summer and fall. In general, Pn was significantly lower in fall as compared to summer. Nevertheless, independent from season mean Pn values tended to increase with elevation and were positively correlated with root zone temperatures. The specific leaf area by contrast declined with increasing elevation. Furthermore, the temperature optimum of net photosynthesis declined with increasing elevation and was positively correlated with the mean maximum air temperature of the 10 days prior the date of measurement. Thus, our findings appear to reflect a long-term adaptation of the photosynthetic apparatus of Pinus cembra to the general temperature conditions with respect to elevation combined with a short term acclimation to the prevailing temperature regime. PMID:21379394

Analysis of long-term changes in extreme climatic indices: a case study of the Mediterranean climate, Marmara Region, Turkey

NASA Astrophysics Data System (ADS)

Abbasnia, Mohsen; Toros, Hüseyin

2018-05-01

This study aimed to analyze extreme temperature and precipitation indices at seven stations in the Marmara Region of Turkey for the period 1961-2016. The trend of temperature indices showed that the warm-spell duration and the numbers of summer days, tropical nights, warm nights, and warm days have increased, while the cold-spell duration and number of ice days, cool nights, and cool days have decreased across the Marmara Region. Additionally, the diurnal temperature range has slightly increased at most of the stations. A majority of stations have shown significant warming trends for warm days and warm nights throughout the study area, whereas warm extremes and night-time based temperature indices have shown stronger trends compared to cold extremes and day-time indices. The analysis of precipitation indices has mostly shown increasing trends in consecutive dry days and increasing trends in annual rainfall, rainfall intensity for inland and urban stations, especially for stations in Sariyer and Edirne, which are affected by a fast rate of urbanization. Overall, a large proportion of study stations have experienced an increase in annual precipitation and heavy precipitation events, although there was a low percentage of results that was significant. Therefore, it is expected that the rainfall events will tend to become shorter and more intense, the occurrence of temperature extremes will become more pronounced in favor of hotter events, and there will be an increase in the atmospheric moisture content over the Marmara Region. This provides regional evidence for the importance of ongoing research on climate change.

The sensitivity of relative toxicity rankings by the USF/NASA test method to some test variables

NASA Technical Reports Server (NTRS)

Hilado, C. J.; Labossiere, L. A.; Leon, H. A.; Kourtides, D. A.; Parker, J. A.; Hsu, M.-T. S.

1976-01-01

Pyrolysis temperature and the distance between the source and sensor of effluents are two important variables in tests for relative toxicity. Modifications of the USF/NASA toxicity screening test method to increase the upper temperature limit of pyrolysis, reduce the distance between the sample and the test animals, and increase the chamber volume available for animal occupancy, did not significantly alter rankings of relative toxicity of four representative materials. The changes rendered some differences no longer significant, but did not reverse any rankings. The materials studied were cotton, wool, aromatic polyamide, and polybenzimidazole.

Clinical safety of 3-T brain magnetic resonance imaging in newborns.

PubMed

Fumagalli, Monica; Cinnante, Claudia Maria; Calloni, Sonia Francesca; Sorrentino, Gabriele; Gorla, Ilaria; Plevani, Laura; Pesenti, Nicola; Sirgiovanni, Ida; Mosca, Fabio; Triulzi, Fabio

2018-03-29

The effects and potential hazards of brain magnetic resonance imaging (MRI) at 3 T in newborns are debated. Assess the impact of 3-T MRI in newborns on body temperature and physiological parameters. Forty-nine newborns, born preterm and at term, underwent 3-T brain MRI at term-corrected age. Rectal and skin temperature, oxygen saturation and heart rate were recorded before, during and after the scan. A statistically significant increase in skin temperature of 0.6 °C was observed at the end of the MRI scan (P<0.01). There was no significant changes in rectal temperature, heart rate or oxygen saturation. Core temperature, heart rate and oxygen saturation in newborns were not affected by 3-T brain MR scanning.

Effect of cold compress application on tissue temperature in healthy dogs.

PubMed

Millard, Ralph P; Towle-Millard, Heather A; Rankin, David C; Roush, James K

2013-03-01

To measure the effect of cold compress application on tissue temperature in healthy dogs. 10 healthy mixed-breed dogs. Dogs were sedated with hydromorphone (0.1 mg/kg, IV) and diazepam (0.25 mg/kg, IV). Three 24-gauge thermocouple needles were inserted to a depth of 0.5 (superficial), 1.0 (middle), and 1.5 (deep) cm into a shaved, lumbar, epaxial region to measure tissue temperature. Cold (-16.8°C) compresses were applied with gravity dependence for periods of 5, 10, and 20 minutes. Tissue temperature was recorded before compress application and at intervals for up to 80 minutes after application. Control data were collected while dogs received identical sedation but with no cold compress. Mean temperature associated with 5 minutes of application at the superficial depth was significantly decreased, compared with control temperatures. Application for 10 and 20 minutes significantly reduced the temperature at all depths, compared with controls and 5 minutes of application. Twenty minutes of application significantly decreased temperature at only the middle depth, compared with 10 minutes of application. With this method of cold treatment, increasing application time from 10 to 20 minutes caused a further significant temperature change at only the middle tissue depth; however, for maximal cooling, the minimum time of application should be 20 minutes. Possible changes in tissue temperature and adverse effects of application > 20 minutes require further evaluation.

Seasonal variation in methane emission from stored slurry and solid manures

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

Husted, S.

1994-05-01

Methane (CH{sub 4}) is an important greenhouse gas and recent inventories have suggested that livestock manure makes a significant contribution to global CH{sub 4} emissions. The emission of CH{sub 4} from stored pig slurry, cattle slurry, pig solid manure, and cattle solid manure was followed during a 1-yr period. Methane emission was determined by dynamic chambers. Emission rates followed a ln-normal distribution for all four manures, Indicating large spatial and seasonal variation& Monthly geometric means for pig slurry, cattle slurry, pig solid manure, and cattle solid manure varied from 0.4 to 35.8, 0.0 to 34.5, 0.4 to 142.1, and 0.1more » to 42.7 g CH{sub 4} m{sup -3} d{sup -1}, respectively. For slurries CH{sub 4} emission rates increased significantly with storage temperatures, the Q{sub 10} value ranging from 14 to 5.7 depending on slurry type. The presence of a natural surface crust reduced CH{sub 4} emission from slurry by a factor of 11 to 12. Surface crust effects declined with increasing slurry temperature. Solid manures stored in dungheaps showed significant heat production. Pig solid manure temperatures were maintained at 30 to 60{degrees}C throughout most of the year, while cattle solid manure temperatures were close to ambient levels until late spring, when heat production was initiated. Methanogenesis in solid manure also increased with increasing temperatures. For pig solid manure, CH{sub 4} emission rates peaked at 35 to 45{degrees}C. No distinct temperature optimum could be detected for cattle solid manure, however, temperatures rarely exceeded 45{degrees}C. The Q{sub 10} values for dungheaps ranged from 2.7 to 10.3 depending on-manure type and Q{sub 10} temperature interval. Annual CH{sub 4} emissions from pig slurry, cattle slurry, pig solid manure, and cattle solid manure were estimated at 8.9, 15.5, 27.3, and 5.3 kg animal{sup -1} yr{sup -1}, respectively. 27 refs., 6 figs., 2 tabs.« less

Changes in Temperature Sensitivity and Activation Energy of Soil Organic Matter Decomposition in Different Qinghai-Tibet Plateau Grasslands

PubMed Central

Li, Jie; He, Nianpeng; Wei, Xuehong; Gao, Yang; Zuo, Yao

2015-01-01

Qinghai-Tibet Plateau grasslands are unique geographical regions and store substantial soil organic matter (SOM) in the soil surface, which make them very sensitive to global climate change. Here, we focused on three main grassland types (alpine meadow, steppe, and desert) and conducted a soil incubation experiment at five different temperatures (5, 10, 15, 20, and 25°C) to investigate SOM decomposition rates (R), temperature sensitivity (Q 10), and activation energy (E a). The results showed that grassland type and incubation temperature had significant impact on R (P < 0.001), and the values of R were exponential correlated with incubation temperature in three alpine grasslands. At the same temperature, R was in the following order: alpine meadow > alpinesteppe > alpine desert. The Q 10 values differed significantly among different grasslands, and the overall trends were as follows: alpine meadow (1.56 ± 0.09) < alpine steppe (1.88 ± 0.23) < alpine desert (2.39 ± 0.32). Moreover, the E a values differed significantly across different grassland types (P < 0.001) and increased with increasing incubation time. The exponential negative correlations between E a and R at 20°C across all grassland types (all Ps < 0.001) indicated that the substrate-quality temperature hypothesis is applicable to the alpine grasslands. Our findings provide new insights for understanding the responses of SOM decomposition and storage to warming scenarios in this Plateau. PMID:26176705

Temperature response of soil respiration largely unaltered with experimental warming.

PubMed

Carey, Joanna C; Tang, Jianwu; Templer, Pamela H; Kroeger, Kevin D; Crowther, Thomas W; Burton, Andrew J; Dukes, Jeffrey S; Emmett, Bridget; Frey, Serita D; Heskel, Mary A; Jiang, Lifen; Machmuller, Megan B; Mohan, Jacqueline; Panetta, Anne Marie; Reich, Peter B; Reinsch, Sabine; Wang, Xin; Allison, Steven D; Bamminger, Chris; Bridgham, Scott; Collins, Scott L; de Dato, Giovanbattista; Eddy, William C; Enquist, Brian J; Estiarte, Marc; Harte, John; Henderson, Amanda; Johnson, Bart R; Larsen, Klaus Steenberg; Luo, Yiqi; Marhan, Sven; Melillo, Jerry M; Peñuelas, Josep; Pfeifer-Meister, Laurel; Poll, Christian; Rastetter, Edward; Reinmann, Andrew B; Reynolds, Lorien L; Schmidt, Inger K; Shaver, Gaius R; Strong, Aaron L; Suseela, Vidya; Tietema, Albert

2016-11-29

The respiratory release of carbon dioxide (CO 2 ) from soil is a major yet poorly understood flux in the global carbon cycle. Climatic warming is hypothesized to increase rates of soil respiration, potentially fueling further increases in global temperatures. However, despite considerable scientific attention in recent decades, the overall response of soil respiration to anticipated climatic warming remains unclear. We synthesize the largest global dataset to date of soil respiration, moisture, and temperature measurements, totaling >3,800 observations representing 27 temperature manipulation studies, spanning nine biomes and over 2 decades of warming. Our analysis reveals no significant differences in the temperature sensitivity of soil respiration between control and warmed plots in all biomes, with the exception of deserts and boreal forests. Thus, our data provide limited evidence of acclimation of soil respiration to experimental warming in several major biome types, contrary to the results from multiple single-site studies. Moreover, across all nondesert biomes, respiration rates with and without experimental warming follow a Gaussian response, increasing with soil temperature up to a threshold of ∼25 °C, above which respiration rates decrease with further increases in temperature. This consistent decrease in temperature sensitivity at higher temperatures demonstrates that rising global temperatures may result in regionally variable responses in soil respiration, with colder climates being considerably more responsive to increased ambient temperatures compared with warmer regions. Our analysis adds a unique cross-biome perspective on the temperature response of soil respiration, information critical to improving our mechanistic understanding of how soil carbon dynamics change with climatic warming.